This is manual.info, produced by makeinfo version 4.8 from manual.texi. START-INFO-DIR-ENTRY * mysql: (mysql). MySQL documentation. END-INFO-DIR-ENTRY  File: manual.info, Node: Top, Next: preface, Prev: (dir), Up: (dir) Copyright (C) 1997, 2011, Oracle and/or its affiliates. All rights reserved. This software and related documentation are provided under a license agreement containing restrictions on use and disclosure and are protected by intellectual property laws. Except as expressly permitted in your license agreement or allowed by law, you may not use, copy, reproduce, translate, broadcast, modify, license, transmit, distribute, exhibit, perform, publish, or display any part, in any form, or by any means. Reverse engineering, disassembly, or decompilation of this software, unless required by law for interoperability, is prohibited. The information contained herein is subject to change without notice and is not warranted to be error-free. 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For additional documentation on MySQL products, including translations of the documentation into other languages, and downloadable versions in variety of formats, including HTML and PDF formats, see the MySQL Documentation Library (http://dev.mysql.com/doc). * Menu: * preface:: Preface and Notes * introduction:: General Information * installing:: Installing and Upgrading MySQL * tutorial:: Tutorial * programs:: MySQL Programs * server-administration:: MySQL Server Administration * backup-and-recovery:: Backup and Recovery * optimization:: Optimization * language-structure:: Language Structure * globalization:: Globalization * data-types:: Data Types * functions:: Functions and Operators * sql-syntax:: SQL Statement Syntax * storage-engines:: Storage Engines * ha-overview:: High Availability and Scalability * replication:: Replication * mysql-cluster:: MySQL Cluster NDB 6.X/7.X * partitioning:: Partitioning * stored-programs-views:: Stored Programs and Views * information-schema:: `INFORMATION_SCHEMA' Tables * connectors-apis:: Connectors and APIs * extending-mysql:: Extending MySQL * mysql-enterprise-monitor:: MySQL Enterprise Monitor * mysql-enterprise-backup:: MySQL Enterprise Backup * workbench:: MySQL Workbench * licenses-third-party:: Licenses for Third-Party Components * faqs:: MySQL 5.1 Frequently Asked Questions * error-handling:: Errors, Error Codes, and Common Problems * news:: MySQL Change History * restrictions:: Restrictions and Limits  File: manual.info, Node: preface, Next: introduction, Prev: Top, Up: Top 1 Preface and Notes ******************* This is the Reference Manual for the MySQL Database System, version 5.1, through release 5.1.59. Differences between minor versions of MySQL 5.1 are noted in the present text with reference to release numbers (5.1.X). For license information, see the legal notice. This product may contain third-party code. For license information on third-party code, see *Note licenses-third-party::. This manual is not intended for use with older versions of the MySQL software due to the many functional and other differences between MySQL 5.1 and previous versions. If you are using an earlier release of the MySQL software, please refer to the appropriate manual. For example, `MySQL 5.0 Reference Manual' (http://dev.mysql.com/doc/refman/5.0/en/), covers the 5.0 series of MySQL software releases. If you are using MySQL 5.5, please refer to the `MySQL 5.5 Reference Manual' (http://dev.mysql.com/doc/refman/5.5/en/).  File: manual.info, Node: introduction, Next: installing, Prev: preface, Up: Top 2 General Information ********************* * Menu: * manual-info:: About This Manual * manual-conventions:: Typographical and Syntax Conventions * what-is:: Overview of the MySQL Database Management System * development-history:: MySQL Development History * mysql-nutshell:: What Is New in MySQL 5.1 * information-sources:: MySQL Information Sources * bug-reports:: How to Report Bugs or Problems * compatibility:: MySQL Standards Compliance * credits:: Credits The MySQL(tm) software delivers a very fast, multi-threaded, multi-user, and robust SQL (Structured Query Language) database server. MySQL Server is intended for mission-critical, heavy-load production systems as well as for embedding into mass-deployed software. Oracle is a registered trademark of Oracle Corporation and/or its affiliates. MySQL is a trademark of Oracle Corporation and/or its affiliates, and shall not be used by Customer without Oracle's express written authorization. Other names may be trademarks of their respective owners. The MySQL software is Dual Licensed. Users can choose to use the MySQL software as an Open Source product under the terms of the GNU General Public License (`http://www.fsf.org/licenses/') or can purchase a standard commercial license from Oracle. See http://www.mysql.com/company/legal/licensing/ for more information on our licensing policies. The following list describes some sections of particular interest in this manual: * For a discussion about the capabilities of the MySQL Database Server, see *Note features::. * For development history, see *Note development-history::. * For installation instructions, see *Note installing::. For information about upgrading MySQL, see *Note upgrading::, and the change notes at *Note news::. * For a tutorial introduction to the MySQL Database Server, see *Note tutorial::. * For information about configuring and administering MySQL Server, see *Note server-administration::. * For information about setting up replication servers, see *Note replication::. * For answers to a number of questions that are often asked concerning the MySQL Database Server and its capabilities, see *Note faqs::. * For a list of currently known bugs and misfeatures, see *Note bugs::. * For a list of all the contributors to this project, see *Note credits::. * For a history of new features and bugfixes, see *Note news::. * For tips on porting the MySQL Database Software to new architectures or operating systems, see MySQL Internals: Porting (http://forge.mysql.com/wiki/MySQL_Internals_Porting). * For benchmarking information, see the `sql-bench' benchmarking directory in your MySQL distribution. *Important*: To report errors (often called `bugs'), please use the instructions at *Note bug-reports::. If you have found a sensitive security bug in MySQL Server, please let us know immediately by sending an email message to .  File: manual.info, Node: manual-info, Next: manual-conventions, Prev: introduction, Up: introduction 2.1 About This Manual ===================== This is the Reference Manual for the MySQL Database System, version 5.1, through release 5.1.59. Differences between minor versions of MySQL 5.1 are noted in the present text with reference to release numbers (5.1.X). This manual is not intended for use with older versions of the MySQL software due to the many functional and other differences between MySQL 5.1 and previous versions. If you are using an earlier release of the MySQL software, please refer to the appropriate manual. For example, `MySQL 5.0 Reference Manual' (http://dev.mysql.com/doc/refman/5.0/en/), covers the 5.0 series of MySQL software releases. If you are using MySQL 5.5, please refer to the `MySQL 5.5 Reference Manual' (http://dev.mysql.com/doc/refman/5.5/en/). Because this manual serves as a reference, it does not provide general instruction on SQL or relational database concepts. It also does not teach you how to use your operating system or command-line interpreter. The MySQL Database Software is under constant development, and the Reference Manual is updated frequently as well. The most recent version of the manual is available online in searchable form at `http://dev.mysql.com/doc/'. Other formats also are available there, including HTML, PDF, and Windows CHM versions. The Reference Manual source files are written in DocBook XML format. The HTML version and other formats are produced automatically, primarily using the DocBook XSL stylesheets. For information about DocBook, see `http://docbook.org/' If you have questions about using MySQL, you can ask them using our mailing lists or forums. See *Note mailing-lists::, and *Note forums::. If you have suggestions concerning additions or corrections to the manual itself, please send them to the http://www.mysql.com/company/contact/. This manual was originally written by David Axmark and Michael `Monty' Widenius. It is maintained by the MySQL Documentation Team, consisting of Paul DuBois, Stefan Hinz, Jon Stephens, Tony Bedford, and John Russell.  File: manual.info, Node: manual-conventions, Next: what-is, Prev: manual-info, Up: introduction 2.2 Typographical and Syntax Conventions ======================================== This manual uses certain typographical conventions: * `Text in this style' is used for SQL statements; database, table, and column names; program listings and source code; and environment variables. Example: `To reload the grant tables, use the *Note `FLUSH PRIVILEGES': flush. statement.' * Text in this style indicates input that you type in examples. * `Text in this style' indicates the names of executable programs and scripts, examples being *Note `mysql': mysql. (the MySQL command line client program) and *Note `mysqld': mysqld. (the MySQL server executable). * TEXT IN THIS STYLE is used for variable input for which you should substitute a value of your own choosing. * _Text in this style_ is used for emphasis. * *Text in this style* is used in table headings and to convey especially strong emphasis. * `Text in this style' is used to indicate a program option that affects how the program is executed, or that supplies information that is needed for the program to function in a certain way. _Example_: `The `--host' option (short form `-h') tells the *Note `mysql': mysql. client program the hostname or IP address of the MySQL server that it should connect to'. * File names and directory names are written like this: `The global `my.cnf' file is located in the `/etc' directory.' * Character sequences are written like this: `To specify a wildcard, use the ``%'' character.' When commands are shown that are meant to be executed from within a particular program, the prompt shown preceding the command indicates which command to use. For example, `shell>' indicates a command that you execute from your login shell, `root-shell>' is similar but should be executed as `root', and `mysql>' indicates a statement that you execute from the *Note `mysql': mysql. client program: shell> type a shell command here root-shell> type a shell command as ROOT here mysql> type a mysql statement here In some areas different systems may be distinguished from each other to show that commands should be executed in two different environments. For example, while working with replication the commands might be prefixed with `master' and `slave': master> type a mysql command on the replication master here slave> type a mysql command on the replication slave here The `shell' is your command interpreter. On Unix, this is typically a program such as `sh', `csh', or `bash'. On Windows, the equivalent program is `command.com' or `cmd.exe', typically run in a console window. When you enter a command or statement shown in an example, do not type the prompt shown in the example. Database, table, and column names must often be substituted into statements. To indicate that such substitution is necessary, this manual uses DB_NAME, TBL_NAME, and COL_NAME. For example, you might see a statement like this: mysql> SELECT COL_NAME FROM DB_NAME.TBL_NAME; This means that if you were to enter a similar statement, you would supply your own database, table, and column names, perhaps like this: mysql> SELECT author_name FROM biblio_db.author_list; SQL keywords are not case sensitive and may be written in any lettercase. This manual uses uppercase. In syntax descriptions, square brackets (``['' and ``]'') indicate optional words or clauses. For example, in the following statement, `IF EXISTS' is optional: DROP TABLE [IF EXISTS] TBL_NAME When a syntax element consists of a number of alternatives, the alternatives are separated by vertical bars (``|''). When one member from a set of choices _may_ be chosen, the alternatives are listed within square brackets (``['' and ``]''): TRIM([[BOTH | LEADING | TRAILING] [REMSTR] FROM] STR) When one member from a set of choices _must_ be chosen, the alternatives are listed within braces (``{'' and ``}''): {DESCRIBE | DESC} TBL_NAME [COL_NAME | WILD] An ellipsis (`...') indicates the omission of a section of a statement, typically to provide a shorter version of more complex syntax. For example, *Note `SELECT ... INTO OUTFILE': select. is shorthand for the form of *Note `SELECT': select. statement that has an `INTO OUTFILE' clause following other parts of the statement. An ellipsis can also indicate that the preceding syntax element of a statement may be repeated. In the following example, multiple RESET_OPTION values may be given, with each of those after the first preceded by commas: RESET RESET_OPTION [,RESET_OPTION] ... Commands for setting shell variables are shown using Bourne shell syntax. For example, the sequence to set the `CC' environment variable and run the `configure' command looks like this in Bourne shell syntax: shell> CC=gcc ./configure If you are using `csh' or `tcsh', you must issue commands somewhat differently: shell> setenv CC gcc shell> ./configure  File: manual.info, Node: what-is, Next: development-history, Prev: manual-conventions, Up: introduction 2.3 Overview of the MySQL Database Management System ==================================================== * Menu: * what-is-mysql:: What is MySQL? * history:: History of MySQL * features:: The Main Features of MySQL  File: manual.info, Node: what-is-mysql, Next: history, Prev: what-is, Up: what-is 2.3.1 What is MySQL? -------------------- MySQL, the most popular Open Source SQL database management system, is developed, distributed, and supported by Oracle Corporation. The MySQL Web site (http://www.mysql.com/) provides the latest information about MySQL software. * MySQL is a database management system. A database is a structured collection of data. It may be anything from a simple shopping list to a picture gallery or the vast amounts of information in a corporate network. To add, access, and process data stored in a computer database, you need a database management system such as MySQL Server. Since computers are very good at handling large amounts of data, database management systems play a central role in computing, as standalone utilities, or as parts of other applications. * MySQL is a relational database management system. A relational database stores data in separate tables rather than putting all the data in one big storeroom. This adds speed and flexibility. The SQL part of `MySQL' stands for `Structured Query Language.' SQL is the most common standardized language used to access databases and is defined by the ANSI/ISO SQL Standard. The SQL standard has been evolving since 1986 and several versions exist. In this manual, `SQL-92' refers to the standard released in 1992, `SQL:1999' refers to the standard released in 1999, and `SQL:2003' refers to the current version of the standard. We use the phrase `the SQL standard' to mean the current version of the SQL Standard at any time. * MySQL software is Open Source. Open Source means that it is possible for anyone to use and modify the software. Anybody can download the MySQL software from the Internet and use it without paying anything. If you wish, you may study the source code and change it to suit your needs. The MySQL software uses the GPL (GNU General Public License), `http://www.fsf.org/licenses/', to define what you may and may not do with the software in different situations. If you feel uncomfortable with the GPL or need to embed MySQL code into a commercial application, you can buy a commercially licensed version from us. See the MySQL Licensing Overview for more information (http://www.mysql.com/company/legal/licensing/). * The MySQL Database Server is very fast, reliable, and easy to use. If that is what you are looking for, you should give it a try. MySQL Server also has a practical set of features developed in close cooperation with our users. You can find a performance comparison of MySQL Server with other database managers on our benchmark page. See *Note mysql-benchmarks::. MySQL Server was originally developed to handle large databases much faster than existing solutions and has been successfully used in highly demanding production environments for several years. Although under constant development, MySQL Server today offers a rich and useful set of functions. Its connectivity, speed, and security make MySQL Server highly suited for accessing databases on the Internet. * MySQL Server works in client/server or embedded systems. The MySQL Database Software is a client/server system that consists of a multi-threaded SQL server that supports different backends, several different client programs and libraries, administrative tools, and a wide range of application programming interfaces (APIs). We also provide MySQL Server as an embedded multi-threaded library that you can link into your application to get a smaller, faster, easier-to-manage standalone product. * A large amount of contributed MySQL software is available. It is very likely that your favorite application or language supports the MySQL Database Server. The official way to pronounce `MySQL' is `My Ess Que Ell' (not `my sequel'), but we do not mind if you pronounce it as `my sequel' or in some other localized way.  File: manual.info, Node: history, Next: features, Prev: what-is-mysql, Up: what-is 2.3.2 History of MySQL ---------------------- We started out with the intention of using the `mSQL' database system to connect to our tables using our own fast low-level (ISAM) routines. However, after some testing, we came to the conclusion that `mSQL' was not fast enough or flexible enough for our needs. This resulted in a new SQL interface to our database but with almost the same API interface as `mSQL'. This API was designed to enable third-party code that was written for use with `mSQL' to be ported easily for use with MySQL. MySQL is named after co-founder Monty Widenius's daughter, My. The name of the MySQL Dolphin (our logo) is `Sakila,' which was chosen from a huge list of names suggested by users in our `Name the Dolphin' contest. The winning name was submitted by Ambrose Twebaze, an Open Source software developer from Swaziland, Africa. According to Ambrose, the feminine name Sakila has its roots in SiSwati, the local language of Swaziland. Sakila is also the name of a town in Arusha, Tanzania, near Ambrose's country of origin, Uganda.  File: manual.info, Node: features, Prev: history, Up: what-is 2.3.3 The Main Features of MySQL -------------------------------- This section describes some of the important characteristics of the MySQL Database Software. See also *Note development-history::. In most respects, the roadmap applies to all versions of MySQL. For information about features as they are introduced into MySQL on a series-specific basis, see the `In a Nutshell' section of the appropriate Manual: * MySQL 5.0: MySQL 5.0 in a Nutshell (http://dev.mysql.com/doc/refman/5.0/en/mysql-nutshell.html) * MySQL 5.1: *Note MySQL 5.1 in a Nutshell: mysql-nutshell. * MySQL 5.5: MySQL 5.5 in a Nutshell (http://dev.mysql.com/doc/refman/5.5/en/mysql-nutshell.html) Internals and Portability: * Written in C and C++. * Tested with a broad range of different compilers. * Works on many different platforms. See *Note supported-os::. * For portability, uses `CMake' in MySQL 5.5 and up. Previous series use GNU Automake, Autoconf, and Libtool. * Tested with Purify (a commercial memory leakage detector) as well as with Valgrind, a GPL tool (`http://developer.kde.org/~sewardj/'). * Uses multi-layered server design with independent modules. * Designed to be fully multi-threaded using kernel threads, to easily use multiple CPUs if they are available. * Provides transactional and nontransactional storage engines. * Uses very fast B-tree disk tables (`MyISAM') with index compression. * Designed to make it relatively easy to add other storage engines. This is useful if you want to provide an SQL interface for an in-house database. * Uses a very fast thread-based memory allocation system. * Executes very fast joins using an optimized nested-loop join. * Implements in-memory hash tables, which are used as temporary tables. * Implements SQL functions using a highly optimized class library that should be as fast as possible. Usually there is no memory allocation at all after query initialization. * Provides the server as a separate program for use in a client/server networked environment, and as a library that can be embedded (linked) into standalone applications. Such applications can be used in isolation or in environments where no network is available. Data Types: * Many data types: signed/unsigned integers 1, 2, 3, 4, and 8 bytes long, *Note `FLOAT': numeric-types, *Note `DOUBLE': numeric-types, *Note `CHAR': char, *Note `VARCHAR': char, *Note `BINARY': binary-varbinary, *Note `VARBINARY': binary-varbinary, *Note `TEXT': blob, *Note `BLOB': blob, *Note `DATE': datetime, *Note `TIME': time, *Note `DATETIME': datetime, *Note `TIMESTAMP': datetime, *Note `YEAR': year, *Note `SET': set, *Note `ENUM': enum, and OpenGIS spatial types. See *Note data-types::. * Fixed-length and variable-length string types. Statements and Functions: * Full operator and function support in the *Note `SELECT': select. list and `WHERE' clause of queries. For example: mysql> SELECT CONCAT(first_name, ' ', last_name) -> FROM citizen -> WHERE income/dependents > 10000 AND age > 30; * Full support for SQL `GROUP BY' and `ORDER BY' clauses. Support for group functions (`COUNT()', `AVG()', `STD()', `SUM()', `MAX()', `MIN()', and `GROUP_CONCAT()'). * Support for `LEFT OUTER JOIN' and `RIGHT OUTER JOIN' with both standard SQL and ODBC syntax. * Support for aliases on tables and columns as required by standard SQL. * Support for *Note `DELETE': delete, *Note `INSERT': insert, *Note `REPLACE': replace, and *Note `UPDATE': update. to return the number of rows that were changed (affected), or to return the number of rows matched instead by setting a flag when connecting to the server. * Support for MySQL-specific *Note `SHOW': show. statements that retrieve information about databases, storage engines, tables, and indexes. MySQL 5.0 adds support for the `INFORMATION_SCHEMA' database, implemented according to standard SQL. * An *Note `EXPLAIN': explain. statement to show how the optimizer resolves a query. * Independence of function names from table or column names. For example, `ABS' is a valid column name. The only restriction is that for a function call, no spaces are permitted between the function name and the ``('' that follows it. See *Note reserved-words::. * You can refer to tables from different databases in the same statement. Security: * A privilege and password system that is very flexible and secure, and that enables host-based verification. * Password security by encryption of all password traffic when you connect to a server. Scalability and Limits: * Support for large databases. We use MySQL Server with databases that contain 50 million records. We also know of users who use MySQL Server with 200,000 tables and about 5,000,000,000 rows. * Support for up to 64 indexes per table (32 before MySQL 4.1.2). Each index may consist of 1 to 16 columns or parts of columns. The maximum index width is 1000 bytes (767 for `InnoDB'); before MySQL 4.1.2, the limit is 500 bytes. An index may use a prefix of a column for *Note `CHAR': char, *Note `VARCHAR': char, *Note `BLOB': blob, or *Note `TEXT': blob. column types. Connectivity: * Clients can connect to MySQL Server using several protocols: * Clients can connect using TCP/IP sockets on any platform. * On Windows systems in the NT family (NT, 2000, XP, 2003, or Vista), clients can connect using named pipes if the server is started with the `--enable-named-pipe' option. In MySQL 4.1 and higher, Windows servers also support shared-memory connections if started with the `--shared-memory' option. Clients can connect through shared memory by using the `--protocol=memory' option. * On Unix systems, clients can connect using Unix domain socket files. * MySQL client programs can be written in many languages. A client library written in C is available for clients written in C or C++, or for any language that provides C bindings. * APIs for C, C++, Eiffel, Java, Perl, PHP, Python, Ruby, and Tcl are available, enabling MySQL clients to be written in many languages. See *Note connectors-apis::. * The Connector/ODBC (MyODBC) interface provides MySQL support for client programs that use ODBC (Open Database Connectivity) connections. For example, you can use MS Access to connect to your MySQL server. Clients can be run on Windows or Unix. MyODBC source is available. All ODBC 2.5 functions are supported, as are many others. See *Note connector-odbc::. * The Connector/J interface provides MySQL support for Java client programs that use JDBC connections. Clients can be run on Windows or Unix. Connector/J source is available. See *Note connector-j::. * MySQL Connector/NET enables developers to easily create .NET applications that require secure, high-performance data connectivity with MySQL. It implements the required ADO.NET interfaces and integrates into ADO.NET aware tools. Developers can build applications using their choice of .NET languages. MySQL Connector/NET is a fully managed ADO.NET driver written in 100% pure C#. See *Note connector-net::. Localization: * The server can provide error messages to clients in many languages. See *Note error-message-language::. * Full support for several different character sets, including `latin1' (cp1252), `german', `big5', `ujis', and more. For example, the Scandinavian characters ``aa'', ``a"'' and ``o"'' are permitted in table and column names. Unicode support is available as of MySQL 4.1. * All data is saved in the chosen character set. * Sorting and comparisons are done according to the chosen character set and collation (using `latin1' and Swedish collation by default). It is possible to change this when the MySQL server is started. To see an example of very advanced sorting, look at the Czech sorting code. MySQL Server supports many different character sets that can be specified at compile time and runtime. * As of MySQL 4.1, the server time zone can be changed dynamically, and individual clients can specify their own time zone. *Note time-zone-support::. Clients and Tools: * MySQL includes several client and utility programs. These include both command-line programs such as *Note `mysqldump': mysqldump. and *Note `mysqladmin': mysqladmin, and graphical programs such as MySQL Administrator and MySQL Query Browser. * MySQL Server has built-in support for SQL statements to check, optimize, and repair tables. These statements are available from the command line through the *Note `mysqlcheck': mysqlcheck. client. MySQL also includes *Note `myisamchk': myisamchk, a very fast command-line utility for performing these operations on `MyISAM' tables. See *Note programs::. * MySQL programs can be invoked with the `--help' or `-?' option to obtain online assistance.  File: manual.info, Node: development-history, Next: mysql-nutshell, Prev: what-is, Up: introduction 2.4 MySQL Development History ============================= This section describes the general MySQL development history, provides an overview about features that have been implemented in previous series and that are new in MySQL 5.1, the release series covered in this manual. The maturity level this release series is general availability. Information about maturity levels can be found in *Note choosing-version::. Before upgrading from one release series to the next, please see the notes in *Note upgrading::. The most requested features and the versions in which they were implemented are summarized in the following table. Feature MySQL Series Unions 4.0 Subqueries 4.1 R-trees 4.1 (for the `MyISAM' storage engine) Stored procedures and 5.0 functions Views 5.0 Cursors 5.0 XA transactions 5.0 Triggers 5.0 and 5.1 Event scheduler 5.1 Partitioning 5.1 Pluggable storage 5.1 engine API Plugin API 5.1 InnoDB Plugin 5.1 Row-based replication 5.1 Server log tables 5.1  File: manual.info, Node: mysql-nutshell, Next: information-sources, Prev: development-history, Up: introduction 2.5 What Is New in MySQL 5.1 ============================ This section summarizes what has been added to MySQL 5.1 and what has been deprecated for further use. The following features have been added to MySQL 5.1: * Partitioning This capability enables distributing portions of individual tables across a file system, according to rules which can be set when the table is created. In effect, different portions of a table are stored as separate tables in different locations, but from the user point of view, the partitioned table is still a single table. Syntactically, this implements a number of new extensions to the *Note `CREATE TABLE': create-table, *Note `ALTER TABLE': alter-table, and `EXPLAIN ... SELECT' statements. As of MySQL 5.1.6, queries against partitioned tables can take advantage of _partition pruning_. In some cases, this can result in query execution that is an order of magnitude faster than the same query against a nonpartitioned version of the same table. See *Note partitioning::, for further information on this functionality. (Author: Mikael Ronstro"m) * Row-based replication Replication capabilities in MySQL originally were based on propagation of SQL statements from master to slave. This is called _statement-based replication_. As of MySQL 5.1.5, another basis for replication is available. This is called _row-based replication_. Instead of sending SQL statements to the slave, the master writes events to its binary log that indicate how individual table rows are effected. As of MySQL 5.1.8, a third option is available: _mixed_. This will use statement-based replication by default, and only switch to row-based replication in particular cases. See *Note replication-formats::. (Authors: Lars Thalmann, Guilhem Bichot, Mats Kindahl) * Plugin API MySQL 5.1 adds support for a very flexible plugin API that enables loading and unloading of various components at runtime, without restarting the server. Although the work on this is not finished yet, _plugin full-text parsers_ are a first step in this direction. This permits users to implement their own input filter on the indexed text, enabling full-text search capability on arbitrary data such as PDF files or other document formats. A pre-parser full-text plugin performs the actual parsing and extraction of the text and hands it over to the built-in MySQL full-text search. See *Note plugin-api::. (Author: Sergey Vojtovich) * Event scheduler MySQL Events are tasks that run according to a schedule. When you create an event, you are creating a named database object containing one or more SQL statements to be executed at one or more regular intervals, beginning and ending at a specific date and time. Conceptually, this is similar to the idea of the Unix `crontab' (also known as a `cron job') or the Windows Task Scheduler. See *Note events::. (Author: Andrey Hristov) * Server log tables Before MySQL 5.1, the server writes general query log and slow query log entries to log files. As of MySQL 5.1, the server's logging capabilities for these logs are more flexible. Log entries can be written to log files (as before) or to the `general_log' and `slow_log' tables in the `mysql' database. If logging is enabled, either or both destinations can be selected. The `--log-output' option controls the destination or destinations of log output. See *Note log-destinations::. (Author: Petr Chardin) * Upgrade program The *Note `mysql_upgrade': mysql-upgrade. program (available as of MySQL 5.1.7) checks all existing tables for incompatibilities with the current version of MySQL Server and repairs them if necessary. This program should be run for each MySQL upgrade. See *Note mysql-upgrade::. (Authors: Alexey Botchkov, Mikael Widenius) * MySQL Cluster MySQL Cluster is now released as a separate product, based on MySQL 5.1 but with the addition of the *Note `NDBCLUSTER': mysql-cluster. storage engine. Clustering support is no longer available in mainline MySQL 5.1 releases. MySQL Cluster releases are identified by a 3-part NDB version number; currently, the MySQL Cluster NDB 6.3, MySQL Cluster NDB 7.0, and MySQL Cluster NDB 7.1 release series are available for production use. Some of the changes in MySQL Cluster since MySQL 5.0 are listed here: * MySQL Cluster replication Replication between MySQL Clusters is now supported. It is now also possible to replicate between a MySQL Cluster and a noncluster database. See *Note mysql-cluster-replication::. * MySQL Cluster disk data storage Formerly, the *Note `NDBCLUSTER': mysql-cluster. storage engine was strictly in-memory; now, it is possible to store Cluster data (but not indexes) on disk. This enables MySQL Cluster to scale upward with fewer hardware (RAM) requirements than previously. In addition, the Disk Data implementation includes a new `no-steal' restoration algorithm for fast node restarts when storing very large amounts of data (terabyte range). See *Note mysql-cluster-disk-data::, for more information. * Improved backups for MySQL Cluster A fault arising in a single data node during a Cluster backup no longer causes the entire backup to be aborted, as occurred in previous versions of MySQL Cluster. Many other new features and improvements have been made to the *Note `NDBCLUSTER': mysql-cluster. storage engine in MySQL Cluster NDB 7.0 and MySQL Cluster NDB 7.1; for more information about these, see *Note mysql-cluster-development::. * Backup of tablespaces The *Note `mysqldump': mysqldump. utility now supports an option for dumping tablespaces. Use `-Y' or `--all-tablespaces' to enable this functionality. * Improvements to `INFORMATION_SCHEMA' MySQL 5.1 provides much more information in its metadata database than was available in MySQL 5.0. New tables in the `INFORMATION_SCHEMA' database include *Note `FILES': files-table, *Note `EVENTS': events-table, *Note `PARTITIONS': partitions-table, *Note `PROCESSLIST': processlist-table, *Note `ENGINES': engines-table, and *Note `PLUGINS': plugins-table. * XML functions with XPath support `ExtractValue()' returns the content of a fragment of XML matching a given XPath expression. `UpdateXML()' replaces the element selected from a fragment of XML by an XPath expression supplied by the user with a second XML fragment (also user-supplied), and returns the modified XML. See *Note xml-functions::. (Author: Alexander Barkov) * Load emulator The *Note `mysqlslap': mysqlslap. program is designed to emulate client load for a MySQL server and report the timing of each stage. It works as if multiple clients were accessing the server. See *Note mysqlslap::. (Authors: Patrick Galbraith, Brian Aker) The following constructs are deprecated and are removed as of MySQL 5.5. Where alternatives are shown, applications should be updated to use them. * The `log_bin_trust_routine_creators' system variable (use `log_bin_trust_function_creators'). * The `table_type' system variable (use `storage_engine'). * The `TYPE' table option to specify the storage engine for *Note `CREATE TABLE': create-table. or *Note `ALTER TABLE': alter-table. (use `ENGINE'). * The `SHOW TABLE TYPES' SQL statement (use *Note `SHOW ENGINES': show-engines.). * The *Note `SHOW INNODB STATUS': show-innodb-status. and `SHOW MUTEX STATUS' SQL statements (use *Note `SHOW ENGINE INNODB STATUS': show-engine. *Note `SHOW ENGINE INNODB MUTEX': show-engine.). * The `SHOW PLUGIN' SQL statement (use *Note `SHOW PLUGINS': show-plugins.). * The `LOAD TABLE ... FROM MASTER' and `LOAD DATA FROM MASTER' SQL statements (use *Note `mysqldump': mysqldump. or *Note `mysqlhotcopy': mysqlhotcopy. to dump tables and *Note `mysql': mysql. to reload dump files). * The *Note `BACKUP TABLE': backup-table. and *Note `RESTORE TABLE': restore-table. SQL statements (use *Note `mysqldump': mysqldump. or *Note `mysqlhotcopy': mysqlhotcopy. to dump tables and *Note `mysql': mysql. to reload dump files). * *Note `TIMESTAMP(N)': datetime. data type: The ability to specify a display width of N (use without N). * The `--master-XXX' server options to set replication parameters (use the *Note `CHANGE MASTER TO': change-master-to. statement instead): `--master-host', `--master-user', `--master-password', `--master-port', `--master-connect-retry', `--master-ssl', `--master-ssl-ca', `--master-ssl-capath', `--master-ssl-cert', `--master-ssl-cipher', `--master-ssl-key'.  File: manual.info, Node: information-sources, Next: bug-reports, Prev: mysql-nutshell, Up: introduction 2.6 MySQL Information Sources ============================= * Menu: * mailing-lists:: MySQL Mailing Lists * forums:: MySQL Community Support at the MySQL Forums * irc:: MySQL Community Support on Internet Relay Chat (IRC) * mysql-enterprise-information:: MySQL Enterprise This section lists sources of additional information that you may find helpful, such as the MySQL mailing lists and user forums, and Internet Relay Chat.  File: manual.info, Node: mailing-lists, Next: forums, Prev: information-sources, Up: information-sources 2.6.1 MySQL Mailing Lists ------------------------- * Menu: * mailing-list-use:: Guidelines for Using the Mailing Lists This section introduces the MySQL mailing lists and provides guidelines as to how the lists should be used. When you subscribe to a mailing list, you receive all postings to the list as email messages. You can also send your own questions and answers to the list. To subscribe to or unsubscribe from any of the mailing lists described in this section, visit `http://lists.mysql.com/'. For most of them, you can select the regular version of the list where you get individual messages, or a digest version where you get one large message per day. Please _do not_ send messages about subscribing or unsubscribing to any of the mailing lists, because such messages are distributed automatically to thousands of other users. Your local site may have many subscribers to a MySQL mailing list. If so, the site may have a local mailing list, so that messages sent from `lists.mysql.com' to your site are propagated to the local list. In such cases, please contact your system administrator to be added to or dropped from the local MySQL list. If you wish to have traffic for a mailing list go to a separate mailbox in your mail program, set up a filter based on the message headers. You can use either the `List-ID:' or `Delivered-To:' headers to identify list messages. The MySQL mailing lists are as follows: * `announce' The list for announcements of new versions of MySQL and related programs. This is a low-volume list to which all MySQL users should subscribe. * `mysql' The main list for general MySQL discussion. Please note that some topics are better discussed on the more-specialized lists. If you post to the wrong list, you may not get an answer. * `bugs' The list for people who want to stay informed about issues reported since the last release of MySQL or who want to be actively involved in the process of bug hunting and fixing. See *Note bug-reports::. * `internals' The list for people who work on the MySQL code. This is also the forum for discussions on MySQL development and for posting patches. * `mysqldoc' The list for people who work on the MySQL documentation. * `benchmarks' The list for anyone interested in performance issues. Discussions concentrate on database performance (not limited to MySQL), but also include broader categories such as performance of the kernel, file system, disk system, and so on. * `packagers' The list for discussions on packaging and distributing MySQL. This is the forum used by distribution maintainers to exchange ideas on packaging MySQL and on ensuring that MySQL looks and feels as similar as possible on all supported platforms and operating systems. * `java' The list for discussions about the MySQL server and Java. It is mostly used to discuss JDBC drivers such as MySQL Connector/J. * `win32' The list for all topics concerning the MySQL software on Microsoft operating systems, such as Windows 9x, Me, NT, 2000, XP, and 2003. * `myodbc' The list for all topics concerning connecting to the MySQL server with ODBC. * `gui-tools' The list for all topics concerning MySQL graphical user interface tools such as `MySQL Administrator' and `MySQL Query Browser'. * `cluster' The list for discussion of MySQL Cluster. * `dotnet' The list for discussion of the MySQL server and the .NET platform. It is mostly related to MySQL Connector/Net. * `plusplus' The list for all topics concerning programming with the C++ API for MySQL. * `perl' The list for all topics concerning Perl support for MySQL with `DBD::mysql'. If you're unable to get an answer to your questions from a MySQL mailing list or forum, one option is to purchase support from Oracle. This puts you in direct contact with MySQL developers. The following MySQL mailing lists are in languages other than English. These lists are not operated by Oracle. * `' A French mailing list. * `' A Korean mailing list. To subscribe, email `subscribe mysql your@email.address' to this list. * `' A German mailing list. To subscribe, email `subscribe mysql-de your@email.address' to this list. You can find information about this mailing list at `http://www.4t2.com/mysql/'. * `' A Portuguese mailing list. To subscribe, email `subscribe mysql-br your@email.address' to this list. * `' A Spanish mailing list. To subscribe, email `subscribe mysql your@email.address' to this list.  File: manual.info, Node: mailing-list-use, Prev: mailing-lists, Up: mailing-lists 2.6.1.1 Guidelines for Using the Mailing Lists .............................................. Please do not post mail messages from your browser with HTML mode turned on. Many users do not read mail with a browser. When you answer a question sent to a mailing list, if you consider your answer to have broad interest, you may want to post it to the list instead of replying directly to the individual who asked. Try to make your answer general enough that people other than the original poster may benefit from it. When you post to the list, please make sure that your answer is not a duplication of a previous answer. Try to summarize the essential part of the question in your reply. Do not feel obliged to quote the entire original message. When answers are sent to you individually and not to the mailing list, it is considered good etiquette to summarize the answers and send the summary to the mailing list so that others may have the benefit of responses you received that helped you solve your problem.  File: manual.info, Node: forums, Next: irc, Prev: mailing-lists, Up: information-sources 2.6.2 MySQL Community Support at the MySQL Forums ------------------------------------------------- The forums at `http://forums.mysql.com' are an important community resource. Many forums are available, grouped into these general categories: * Migration * MySQL Usage * MySQL Connectors * Programming Languages * Tools * 3rd-Party Applications * Storage Engines * MySQL Technology * SQL Standards * Business  File: manual.info, Node: irc, Next: mysql-enterprise-information, Prev: forums, Up: information-sources 2.6.3 MySQL Community Support on Internet Relay Chat (IRC) ---------------------------------------------------------- In addition to the various MySQL mailing lists and forums, you can find experienced community people on Internet Relay Chat (IRC). These are the best networks/channels currently known to us: *freenode* (see `http://www.freenode.net/' for servers) * `#mysql' is primarily for MySQL questions, but other database and general SQL questions are welcome. Questions about PHP, Perl, or C in combination with MySQL are also common. If you are looking for IRC client software to connect to an IRC network, take a look at `xChat' (`http://www.xchat.org/'). X-Chat (GPL licensed) is available for Unix as well as for Windows platforms (a free Windows build of X-Chat is available at `http://www.silverex.org/download/').  File: manual.info, Node: mysql-enterprise-information, Prev: irc, Up: information-sources 2.6.4 MySQL Enterprise ---------------------- Oracle offers technical support in the form of MySQL Enterprise. For organizations that rely on the MySQL DBMS for business-critical production applications, MySQL Enterprise is a commercial subscription offering which includes: * MySQL Enterprise Server * MySQL Enterprise Monitor * Monthly Rapid Updates and Quarterly Service Packs * MySQL Knowledge Base * 24x7 Technical and Consultative Support MySQL Enterprise is available in multiple tiers, giving you the flexibility to choose the level of service that best matches your needs. For more information, see MySQL Enterprise (http://www.mysql.com/products/enterprise/).  File: manual.info, Node: bug-reports, Next: compatibility, Prev: information-sources, Up: introduction 2.7 How to Report Bugs or Problems ================================== Before posting a bug report about a problem, please try to verify that it is a bug and that it has not been reported already: * Start by searching the MySQL online manual at `http://dev.mysql.com/doc/'. We try to keep the manual up to date by updating it frequently with solutions to newly found problems. The change history (`http://dev.mysql.com/doc/mysql/en/news.html') can be particularly useful since it is quite possible that a newer version contains a solution to your problem. * If you get a parse error for an SQL statement, please check your syntax closely. If you cannot find something wrong with it, it is extremely likely that your current version of MySQL Server doesn't support the syntax you are using. If you are using the current version and the manual doesn't cover the syntax that you are using, MySQL Server doesn't support your statement. In this case, your options are to implement the syntax yourself or email and ask for an offer to implement it. If the manual covers the syntax you are using, but you have an older version of MySQL Server, you should check the MySQL change history to see when the syntax was implemented. In this case, you have the option of upgrading to a newer version of MySQL Server. * For solutions to some common problems, see *Note problems::. * Search the bugs database at `http://bugs.mysql.com/' to see whether the bug has been reported and fixed. * Search the MySQL mailing list archives at `http://lists.mysql.com/'. See *Note mailing-lists::. * You can also use http://www.mysql.com/search/ to search all the Web pages (including the manual) that are located at the MySQL Web site. If you cannot find an answer in the manual, the bugs database, or the mailing list archives, check with your local MySQL expert. If you still cannot find an answer to your question, please use the following guidelines for reporting the bug. The normal way to report bugs is to visit `http://bugs.mysql.com/', which is the address for our bugs database. This database is public and can be browsed and searched by anyone. If you log in to the system, you can enter new reports. Bugs posted in the bugs database at `http://bugs.mysql.com/' that are corrected for a given release are noted in the change history. If you have found a sensitive security bug in MySQL, you can send email to . To discuss problems with other users, you can use one of the MySQL mailing lists. *Note mailing-lists::. Writing a good bug report takes patience, but doing it right the first time saves time both for us and for yourself. A good bug report, containing a full test case for the bug, makes it very likely that we will fix the bug in the next release. This section helps you write your report correctly so that you do not waste your time doing things that may not help us much or at all. Please read this section carefully and make sure that all the information described here is included in your report. Preferably, you should test the problem using the latest production or development version of MySQL Server before posting. Anyone should be able to repeat the bug by just using `mysql test < script_file' on your test case or by running the shell or Perl script that you include in the bug report. Any bug that we are able to repeat has a high chance of being fixed in the next MySQL release. It is most helpful when a good description of the problem is included in the bug report. That is, give a good example of everything you did that led to the problem and describe, in exact detail, the problem itself. The best reports are those that include a full example showing how to reproduce the bug or problem. See MySQL Internals: Porting (http://forge.mysql.com/wiki/MySQL_Internals_Porting). Remember that it is possible for us to respond to a report containing too much information, but not to one containing too little. People often omit facts because they think they know the cause of a problem and assume that some details do not matter. A good principle to follow is that if you are in doubt about stating something, state it. It is faster and less troublesome to write a couple more lines in your report than to wait longer for the answer if we must ask you to provide information that was missing from the initial report. The most common errors made in bug reports are (a) not including the version number of the MySQL distribution that you use, and (b) not fully describing the platform on which the MySQL server is installed (including the platform type and version number). These are highly relevant pieces of information, and in 99 cases out of 100, the bug report is useless without them. Very often we get questions like, `Why doesn't this work for me?' Then we find that the feature requested wasn't implemented in that MySQL version, or that a bug described in a report has been fixed in newer MySQL versions. Errors often are platform-dependent. In such cases, it is next to impossible for us to fix anything without knowing the operating system and the version number of the platform. If you compiled MySQL from source, remember also to provide information about your compiler if it is related to the problem. Often people find bugs in compilers and think the problem is MySQL-related. Most compilers are under development all the time and become better version by version. To determine whether your problem depends on your compiler, we need to know what compiler you used. Note that every compiling problem should be regarded as a bug and reported accordingly. If a program produces an error message, it is very important to include the message in your report. If we try to search for something from the archives, it is better that the error message reported exactly matches the one that the program produces. (Even the lettercase should be observed.) It is best to copy and paste the entire error message into your report. You should never try to reproduce the message from memory. If you have a problem with Connector/ODBC (MyODBC), please try to generate a trace file and send it with your report. See the MyODBC section of *Note connectors-apis::. If your report includes long query output lines from test cases that you run with the *Note `mysql': mysql. command-line tool, you can make the output more readable by using the `--vertical' option or the `\G' statement terminator. The *Note `EXPLAIN SELECT': explain. example later in this section demonstrates the use of `\G'. Please include the following information in your report: * The version number of the MySQL distribution you are using (for example, MySQL 5.0.19). You can find out which version you are running by executing *Note `mysqladmin version': mysqladmin. The *Note `mysqladmin': mysqladmin. program can be found in the `bin' directory under your MySQL installation directory. * The manufacturer and model of the machine on which you experience the problem. * The operating system name and version. If you work with Windows, you can usually get the name and version number by double-clicking your My Computer icon and pulling down the `Help/About Windows' menu. For most Unix-like operating systems, you can get this information by executing the command `uname -a'. * Sometimes the amount of memory (real and virtual) is relevant. If in doubt, include these values. * If you are using a source distribution of the MySQL software, include the name and version number of the compiler that you used. If you have a binary distribution, include the distribution name. * If the problem occurs during compilation, include the exact error messages and also a few lines of context around the offending code in the file where the error occurs. * If *Note `mysqld': mysqld. died, you should also report the statement that crashed *Note `mysqld': mysqld. You can usually get this information by running *Note `mysqld': mysqld. with query logging enabled, and then looking in the log after *Note `mysqld': mysqld. crashes. See MySQL Internals: Porting (http://forge.mysql.com/wiki/MySQL_Internals_Porting). * If a database table is related to the problem, include the output from the `SHOW CREATE TABLE DB_NAME.TBL_NAME' statement in the bug report. This is a very easy way to get the definition of any table in a database. The information helps us create a situation matching the one that you have experienced. * The SQL mode in effect when the problem occurred can be significant, so please report the value of the `sql_mode' system variable. For stored procedure, stored function, and trigger objects, the relevant `sql_mode' value is the one in effect when the object was created. For a stored procedure or function, the *Note `SHOW CREATE PROCEDURE': show-create-procedure. or *Note `SHOW CREATE FUNCTION': show-create-function. statement shows the relevant SQL mode, or you can query `INFORMATION_SCHEMA' for the information: SELECT ROUTINE_SCHEMA, ROUTINE_NAME, SQL_MODE FROM INFORMATION_SCHEMA.ROUTINES; For triggers, you can use this statement: SELECT EVENT_OBJECT_SCHEMA, EVENT_OBJECT_TABLE, TRIGGER_NAME, SQL_MODE FROM INFORMATION_SCHEMA.TRIGGERS; * For performance-related bugs or problems with *Note `SELECT': select. statements, you should always include the output of `EXPLAIN SELECT ...', and at least the number of rows that the *Note `SELECT': select. statement produces. You should also include the output from `SHOW CREATE TABLE TBL_NAME' for each table that is involved. The more information you provide about your situation, the more likely it is that someone can help you. The following is an example of a very good bug report. The statements are run using the *Note `mysql': mysql. command-line tool. Note the use of the `\G' statement terminator for statements that would otherwise provide very long output lines that are difficult to read. mysql> SHOW VARIABLES; mysql> SHOW COLUMNS FROM ...\G mysql> EXPLAIN SELECT ...\G mysql> FLUSH STATUS; mysql> SELECT ...; mysql> SHOW STATUS; * If a bug or problem occurs while running *Note `mysqld': mysqld, try to provide an input script that reproduces the anomaly. This script should include any necessary source files. The more closely the script can reproduce your situation, the better. If you can make a reproducible test case, you should upload it to be attached to the bug report. If you cannot provide a script, you should at least include the output from *Note `mysqladmin variables extended-status processlist': mysqladmin. in your report to provide some information on how your system is performing. * If you cannot produce a test case with only a few rows, or if the test table is too big to be included in the bug report (more than 10 rows), you should dump your tables using *Note `mysqldump': mysqldump. and create a `README' file that describes your problem. Create a compressed archive of your files using `tar' and `gzip' or `zip', and use FTP to transfer the archive to `ftp://ftp.mysql.com/pub/mysql/upload/'. Then enter the problem into our bugs database at `http://bugs.mysql.com/'. * If you believe that the MySQL server produces a strange result from a statement, include not only the result, but also your opinion of what the result should be, and an explanation describing the basis for your opinion. * When you provide an example of the problem, it is better to use the table names, variable names, and so forth that exist in your actual situation than to come up with new names. The problem could be related to the name of a table or variable. These cases are rare, perhaps, but it is better to be safe than sorry. After all, it should be easier for you to provide an example that uses your actual situation, and it is by all means better for us. If you have data that you do not want to be visible to others in the bug report, you can use FTP to transfer it to `ftp://ftp.mysql.com/pub/mysql/upload/'. If the information is really top secret and you do not want to show it even to us, go ahead and provide an example using other names, but please regard this as the last choice. * Include all the options given to the relevant programs, if possible. For example, indicate the options that you use when you start the *Note `mysqld': mysqld. server, as well as the options that you use to run any MySQL client programs. The options to programs such as *Note `mysqld': mysqld. and *Note `mysql': mysql, and to the `configure' script, are often key to resolving problems and are very relevant. It is never a bad idea to include them. If your problem involves a program written in a language such as Perl or PHP, please include the language processor's version number, as well as the version for any modules that the program uses. For example, if you have a Perl script that uses the `DBI' and `DBD::mysql' modules, include the version numbers for Perl, `DBI', and `DBD::mysql'. * If your question is related to the privilege system, please include the output of *Note `mysqlaccess': mysqlaccess, the output of *Note `mysqladmin reload': mysqladmin, and all the error messages you get when trying to connect. When you test your privileges, you should first run *Note `mysqlaccess': mysqlaccess. After this, execute *Note `mysqladmin reload version': mysqladmin. and try to connect with the program that gives you trouble. *Note `mysqlaccess': mysqlaccess. can be found in the `bin' directory under your MySQL installation directory. * If you have a patch for a bug, do include it. But do not assume that the patch is all we need, or that we can use it, if you do not provide some necessary information such as test cases showing the bug that your patch fixes. We might find problems with your patch or we might not understand it at all. If so, we cannot use it. If we cannot verify the exact purpose of the patch, we will not use it. Test cases help us here. Show that the patch handles all the situations that may occur. If we find a borderline case (even a rare one) where the patch will not work, it may be useless. * Guesses about what the bug is, why it occurs, or what it depends on are usually wrong. Even the MySQL team cannot guess such things without first using a debugger to determine the real cause of a bug. * Indicate in your bug report that you have checked the reference manual and mail archive so that others know you have tried to solve the problem yourself. * If the problem is that your data appears corrupt or you get errors when you access a particular table, you should first check your tables and then try to repair them with *Note `CHECK TABLE': check-table. and *Note `REPAIR TABLE': repair-table. or with *Note `myisamchk': myisamchk. See *Note server-administration::. If you are running Windows, please verify the value of `lower_case_table_names' using the `SHOW VARIABLES LIKE 'lower_case_table_names'' statement. This variable affects how the server handles lettercase of database and table names. Its effect for a given value should be as described in *Note identifier-case-sensitivity::. * If you often get corrupted tables, you should try to find out when and why this happens. In this case, the error log in the MySQL data directory may contain some information about what happened. (This is the file with the `.err' suffix in the name.) See *Note error-log::. Please include any relevant information from this file in your bug report. Normally *Note `mysqld': mysqld. should _never_ crash a table if nothing killed it in the middle of an update. If you can find the cause of *Note `mysqld': mysqld. dying, it is much easier for us to provide you with a fix for the problem. See *Note what-is-crashing::. * If possible, download and install the most recent version of MySQL Server and check whether it solves your problem. All versions of the MySQL software thoroughly tested and should work without problems. We believe in making everything as backward-compatible as possible, and you should be able to switch MySQL versions without difficulty. See *Note which-version::.  File: manual.info, Node: compatibility, Next: credits, Prev: bug-reports, Up: introduction 2.8 MySQL Standards Compliance ============================== * Menu: * standards:: What Standards MySQL Follows * sql-mode:: Selecting SQL Modes * ansi-mode:: Running MySQL in ANSI Mode * extensions-to-ansi:: MySQL Extensions to Standard SQL * differences-from-ansi:: MySQL Differences from Standard SQL * constraints:: How MySQL Deals with Constraints This section describes how MySQL relates to the ANSI/ISO SQL standards. MySQL Server has many extensions to the SQL standard, and here you can find out what they are and how to use them. You can also find information about functionality missing from MySQL Server, and how to work around some of the differences. The SQL standard has been evolving since 1986 and several versions exist. In this manual, `SQL-92' refers to the standard released in 1992, `SQL:1999' refers to the standard released in 1999, `SQL:2003' refers to the standard released in 2003, and `SQL:2008' refers to the most recent version of the standard, released in 2008. We use the phrase `the SQL standard' or `standard SQL' to mean the current version of the SQL Standard at any time. One of our main goals with the product is to continue to work toward compliance with the SQL standard, but without sacrificing speed or reliability. We are not afraid to add extensions to SQL or support for non-SQL features if this greatly increases the usability of MySQL Server for a large segment of our user base. The *Note `HANDLER': handler. interface is an example of this strategy. See *Note handler::. We continue to support transactional and nontransactional databases to satisfy both mission-critical 24/7 usage and heavy Web or logging usage. MySQL Server was originally designed to work with medium-sized databases (10-100 million rows, or about 100MB per table) on small computer systems. Today MySQL Server handles terabyte-sized databases, but the code can also be compiled in a reduced version suitable for hand-held and embedded devices. The compact design of the MySQL server makes development in both directions possible without any conflicts in the source tree. Currently, we are not targeting real-time support, although MySQL replication capabilities offer significant functionality. MySQL supports high-availability database clustering using the *Note `NDBCLUSTER': mysql-cluster. storage engine. See *Note mysql-cluster::. We are implementing XML functionality beginning in MySQL 5.1, which supports most of the W3C XPath standard. We plan to increase support for XML as part of future MySQL development. See *Note xml-functions::.  File: manual.info, Node: standards, Next: sql-mode, Prev: compatibility, Up: compatibility 2.8.1 What Standards MySQL Follows ---------------------------------- Our aim is to support the full ANSI/ISO SQL standard, but without making concessions to speed and quality of the code. ODBC levels 0 to 3.51.  File: manual.info, Node: sql-mode, Next: ansi-mode, Prev: standards, Up: compatibility 2.8.2 Selecting SQL Modes ------------------------- The MySQL server can operate in different SQL modes, and can apply these modes differentially for different clients. This capability enables each application to tailor the server's operating mode to its own requirements. SQL modes control aspects of server operation such as what SQL syntax MySQL should support and what kind of data validation checks it should perform. This makes it easier to use MySQL in different environments and to use MySQL together with other database servers. You can set the default SQL mode by starting *Note `mysqld': mysqld. with the `--sql-mode="MODE_VALUE"' option. You can also change the mode at runtime by setting the `sql_mode' system variable with a *Note `SET [GLOBAL|SESSION] sql_mode='MODE_VALUE'': set-option. statement. For more information on setting the SQL mode, see *Note server-sql-mode::.  File: manual.info, Node: ansi-mode, Next: extensions-to-ansi, Prev: sql-mode, Up: compatibility 2.8.3 Running MySQL in ANSI Mode -------------------------------- You can tell *Note `mysqld': mysqld. to run in ANSI mode with the `--ansi' startup option. Running the server in ANSI mode is the same as starting it with the following options: --transaction-isolation=SERIALIZABLE --sql-mode=ANSI You can achieve the same effect at runtime by executing these two statements: SET GLOBAL TRANSACTION ISOLATION LEVEL SERIALIZABLE; SET GLOBAL sql_mode = 'ANSI'; You can see that setting the `sql_mode' system variable to `'ANSI'' enables all SQL mode options that are relevant for ANSI mode as follows: mysql> SET GLOBAL sql_mode='ANSI'; mysql> SELECT @@global.sql_mode; -> 'REAL_AS_FLOAT,PIPES_AS_CONCAT,ANSI_QUOTES,IGNORE_SPACE,ANSI' Running the server in ANSI mode with `--ansi' is not quite the same as setting the SQL mode to `'ANSI''. The `--ansi' option affects the SQL mode and also sets the transaction isolation level. Setting the SQL mode to `'ANSI'' has no effect on the isolation level. See *Note server-options::, and *Note sql-mode::.  File: manual.info, Node: extensions-to-ansi, Next: differences-from-ansi, Prev: ansi-mode, Up: compatibility 2.8.4 MySQL Extensions to Standard SQL -------------------------------------- MySQL Server supports some extensions that you probably won't find in other SQL DBMSs. Be warned that if you use them, your code won't be portable to other SQL servers. In some cases, you can write code that includes MySQL extensions, but is still portable, by using comments of the following form: /*! MYSQL-SPECIFIC CODE */ In this case, MySQL Server parses and executes the code within the comment as it would any other SQL statement, but other SQL servers will ignore the extensions. For example, MySQL Server recognizes the `STRAIGHT_JOIN' keyword in the following statement, but other servers will not: SELECT /*! STRAIGHT_JOIN */ col1 FROM table1,table2 WHERE ... If you add a version number after the ``!'' character, the syntax within the comment is executed only if the MySQL version is greater than or equal to the specified version number. The `TEMPORARY' keyword in the following comment is executed only by servers from MySQL 3.23.02 or higher: CREATE /*!32302 TEMPORARY */ TABLE t (a INT); The following descriptions list MySQL extensions, organized by category. * Organization of data on disk MySQL Server maps each database to a directory under the MySQL data directory, and maps tables within a database to file names in the database directory. This has a few implications: * Database and table names are case sensitive in MySQL Server on operating systems that have case-sensitive file names (such as most Unix systems). See *Note identifier-case-sensitivity::. * You can use standard system commands to back up, rename, move, delete, and copy tables that are managed by the `MyISAM' storage engine. For example, it is possible to rename a `MyISAM' table by renaming the `.MYD', `.MYI', and `.frm' files to which the table corresponds. (Nevertheless, it is preferable to use *Note `RENAME TABLE': rename-table. or `ALTER TABLE ... RENAME' and let the server rename the files.) Prior to MySQL 5.1.6, database and table names cannot contain path name separator characters (``/'', ``\''). * General language syntax * By default, strings can be enclosed by either ``"'' or ``''', not just by ``'''. (If the `ANSI_QUOTES' SQL mode is enabled, strings can be enclosed only by ``''' and the server interprets strings enclosed by ``"'' as identifiers.) * ``\'' is the escape character in strings. * In SQL statements, you can access tables from different databases with the DB_NAME.TBL_NAME syntax. Some SQL servers provide the same functionality but call this `User space'. MySQL Server doesn't support tablespaces such as used in statements like this: `CREATE TABLE ralph.my_table ... IN my_tablespace'. * SQL statement syntax * The *Note `ANALYZE TABLE': analyze-table, *Note `CHECK TABLE': check-table, *Note `OPTIMIZE TABLE': optimize-table, and *Note `REPAIR TABLE': repair-table. statements. * The *Note `CREATE DATABASE': create-database, *Note `DROP DATABASE': drop-database, and *Note `ALTER DATABASE': alter-database. statements. See *Note create-database::, *Note drop-database::, and *Note alter-database::. * The *Note `DO': do. statement. * *Note `EXPLAIN SELECT': explain. to obtain a description of how tables are processed by the query optimizer. * The *Note `FLUSH': flush. and *Note `RESET': reset. statements. * The *Note `SET': set-option. statement. See *Note set-option::. * The *Note `SHOW': show. statement. See *Note show::. The information produced by many of the MySQL-specific *Note `SHOW': show. statements can be obtained in more standard fashion by using *Note `SELECT': select. to query `INFORMATION_SCHEMA'. See *Note information-schema::. * Use of *Note `LOAD DATA INFILE': load-data. In many cases, this syntax is compatible with Oracle's *Note `LOAD DATA INFILE': load-data. See *Note load-data::. * Use of *Note `RENAME TABLE': rename-table. See *Note rename-table::. * Use of *Note `REPLACE': replace. instead of *Note `DELETE': delete. plus *Note `INSERT': insert. See *Note replace::. * Use of `CHANGE COL_NAME', `DROP COL_NAME', or *Note `DROP INDEX': drop-index, `IGNORE' or `RENAME' in *Note `ALTER TABLE': alter-table. statements. Use of multiple `ADD', `ALTER', `DROP', or `CHANGE' clauses in an *Note `ALTER TABLE': alter-table. statement. See *Note alter-table::. * Use of index names, indexes on a prefix of a column, and use of `INDEX' or `KEY' in *Note `CREATE TABLE': create-table. statements. See *Note create-table::. * Use of `TEMPORARY' or `IF NOT EXISTS' with *Note `CREATE TABLE': create-table. * Use of `IF EXISTS' with *Note `DROP TABLE': drop-table. and *Note `DROP DATABASE': drop-database. * The capability of dropping multiple tables with a single *Note `DROP TABLE': drop-table. statement. * The `ORDER BY' and `LIMIT' clauses of the *Note `UPDATE': update. and *Note `DELETE': delete. statements. * `INSERT INTO TBL_NAME SET COL_NAME = ...' syntax. * The `DELAYED' clause of the *Note `INSERT': insert. and *Note `REPLACE': replace. statements. * The `LOW_PRIORITY' clause of the *Note `INSERT': insert, *Note `REPLACE': replace, *Note `DELETE': delete, and *Note `UPDATE': update. statements. * Use of `INTO OUTFILE' or `INTO DUMPFILE' in *Note `SELECT': select. statements. See *Note select::. * Options such as `STRAIGHT_JOIN' or `SQL_SMALL_RESULT' in *Note `SELECT': select. statements. * You don't need to name all selected columns in the `GROUP BY' clause. This gives better performance for some very specific, but quite normal queries. See *Note group-by-functions-and-modifiers::. * You can specify `ASC' and `DESC' with `GROUP BY', not just with `ORDER BY'. * The ability to set variables in a statement with the `:=' assignment operator. See *Note user-variables::. * Data types * The *Note `MEDIUMINT': numeric-types, *Note `SET': set, and *Note `ENUM': enum. data types, and the various *Note `BLOB': blob. and *Note `TEXT': blob. data types. * The `AUTO_INCREMENT', `BINARY', `NULL', `UNSIGNED', and `ZEROFILL' data type attributes. * Functions and operators * To make it easier for users who migrate from other SQL environments, MySQL Server supports aliases for many functions. For example, all string functions support both standard SQL syntax and ODBC syntax. * MySQL Server understands the `||' and `&&' operators to mean logical OR and AND, as in the C programming language. In MySQL Server, `||' and `OR' are synonyms, as are `&&' and `AND'. Because of this nice syntax, MySQL Server doesn't support the standard SQL `||' operator for string concatenation; use `CONCAT()' instead. Because `CONCAT()' takes any number of arguments, it is easy to convert use of the `||' operator to MySQL Server. * Use of `COUNT(DISTINCT VALUE_LIST)' where VALUE_LIST has more than one element. * String comparisons are case-insensitive by default, with sort ordering determined by the collation of the current character set, which is `latin1' (cp1252 West European) by default. If you don't like this, you should declare your columns with the `BINARY' attribute or use the `BINARY' cast, which causes comparisons to be done using the underlying character code values rather then a lexical ordering. * The `%' operator is a synonym for `MOD()'. That is, `N % M' is equivalent to `MOD(N,M)'. `%' is supported for C programmers and for compatibility with PostgreSQL. * The `=', `<>', `<=', `<', `>=', `>', `<<', `>>', `<=>', `AND', `OR', or `LIKE' operators may be used in expressions in the output column list (to the left of the `FROM') in *Note `SELECT': select. statements. For example: mysql> SELECT col1=1 AND col2=2 FROM my_table; * The `LAST_INSERT_ID()' function returns the most recent `AUTO_INCREMENT' value. See *Note information-functions::. * `LIKE' is permitted on numeric values. * The `REGEXP' and `NOT REGEXP' extended regular expression operators. * `CONCAT()' or `CHAR()' with one argument or more than two arguments. (In MySQL Server, these functions can take a variable number of arguments.) * The `BIT_COUNT()', `CASE', `ELT()', `FROM_DAYS()', `FORMAT()', `IF()', `PASSWORD()', `ENCRYPT()', `MD5()', `ENCODE()', `DECODE()', `PERIOD_ADD()', `PERIOD_DIFF()', `TO_DAYS()', and `WEEKDAY()' functions. * Use of `TRIM()' to trim substrings. Standard SQL supports removal of single characters only. * The `GROUP BY' functions `STD()', `BIT_OR()', `BIT_AND()', `BIT_XOR()', and `GROUP_CONCAT()'. See *Note group-by-functions-and-modifiers::.  File: manual.info, Node: differences-from-ansi, Next: constraints, Prev: extensions-to-ansi, Up: compatibility 2.8.5 MySQL Differences from Standard SQL ----------------------------------------- * Menu: * ansi-diff-select-into-table:: `SELECT INTO TABLE' * ansi-diff-update:: `UPDATE' * ansi-diff-transactions:: Transactions and Atomic Operations * ansi-diff-foreign-keys:: Foreign Keys * ansi-diff-comments:: '`--'' as the Start of a Comment We try to make MySQL Server follow the ANSI SQL standard and the ODBC SQL standard, but MySQL Server performs operations differently in some cases: * There are several differences between the MySQL and standard SQL privilege systems. For example, in MySQL, privileges for a table are not automatically revoked when you delete a table. You must explicitly issue a *Note `REVOKE': revoke. statement to revoke privileges for a table. For more information, see *Note revoke::. * The `CAST()' function does not support cast to *Note `REAL': numeric-types. or *Note `BIGINT': numeric-types. See *Note cast-functions::.  File: manual.info, Node: ansi-diff-select-into-table, Next: ansi-diff-update, Prev: differences-from-ansi, Up: differences-from-ansi 2.8.5.1 `SELECT INTO TABLE' ........................... MySQL Server doesn't support the `SELECT ... INTO TABLE' Sybase SQL extension. Instead, MySQL Server supports the *Note `INSERT INTO ... SELECT': insert-select. standard SQL syntax, which is basically the same thing. See *Note insert-select::. For example: INSERT INTO tbl_temp2 (fld_id) SELECT tbl_temp1.fld_order_id FROM tbl_temp1 WHERE tbl_temp1.fld_order_id > 100; Alternatively, you can use *Note `SELECT ... INTO OUTFILE': select. or *Note `CREATE TABLE ... SELECT': create-table. You can use *Note `SELECT ... INTO': select. with user-defined variables. The same syntax can also be used inside stored routines using cursors and local variables. See *Note select-into-statement::.  File: manual.info, Node: ansi-diff-update, Next: ansi-diff-transactions, Prev: ansi-diff-select-into-table, Up: differences-from-ansi 2.8.5.2 `UPDATE' ................ If you access a column from the table to be updated in an expression, *Note `UPDATE': update. uses the current value of the column. The second assignment in the following statement sets `col2' to the current (updated) `col1' value, not the original `col1' value. The result is that `col1' and `col2' have the same value. This behavior differs from standard SQL. UPDATE t1 SET col1 = col1 + 1, col2 = col1;  File: manual.info, Node: ansi-diff-transactions, Next: ansi-diff-foreign-keys, Prev: ansi-diff-update, Up: differences-from-ansi 2.8.5.3 Transactions and Atomic Operations .......................................... MySQL Server (version 3.23-max and all versions 4.0 and above) supports transactions with the `InnoDB' transactional storage engine. `InnoDB' provides _full_ ACID compliance. See *Note storage-engines::. For information about `InnoDB' differences from standard SQL with regard to treatment of transaction errors, see *Note innodb-error-handling::. The other nontransactional storage engines in MySQL Server (such as `MyISAM') follow a different paradigm for data integrity called `atomic operations.' In transactional terms, `MyISAM' tables effectively always operate in `autocommit = 1' mode. Atomic operations often offer comparable integrity with higher performance. Because MySQL Server supports both paradigms, you can decide whether your applications are best served by the speed of atomic operations or the use of transactional features. This choice can be made on a per-table basis. As noted, the tradeoff for transactional versus nontransactional storage engines lies mostly in performance. Transactional tables have significantly higher memory and disk space requirements, and more CPU overhead. On the other hand, transactional storage engines such as `InnoDB' also offer many significant features. MySQL Server's modular design enables the concurrent use of different storage engines to suit different requirements and deliver optimum performance in all situations. But how do you use the features of MySQL Server to maintain rigorous integrity even with the nontransactional `MyISAM' tables, and how do these features compare with the transactional storage engines? * If your applications are written in a way that is dependent on being able to call *Note `ROLLBACK': commit. rather than *Note `COMMIT': commit. in critical situations, transactions are more convenient. Transactions also ensure that unfinished updates or corrupting activities are not committed to the database; the server is given the opportunity to do an automatic rollback and your database is saved. If you use nontransactional tables, MySQL Server in almost all cases enables you to resolve potential problems by including simple checks before updates and by running simple scripts that check the databases for inconsistencies and automatically repair or warn if such an inconsistency occurs. You can normally fix tables perfectly with no data integrity loss just by using the MySQL log or even adding one extra log. * More often than not, critical transactional updates can be rewritten to be atomic. Generally speaking, all integrity problems that transactions solve can be done with *Note `LOCK TABLES': lock-tables. or atomic updates, ensuring that there are no automatic aborts from the server, which is a common problem with transactional database systems. * To be safe with MySQL Server, regardless of whether you use transactional tables, you only need to have backups and have binary logging turned on. When that is true, you can recover from any situation that you could with any other transactional database system. It is always good to have backups, regardless of which database system you use. The transactional paradigm has its advantages and disadvantages. Many users and application developers depend on the ease with which they can code around problems where an abort appears to be necessary, or is necessary. However, even if you are new to the atomic operations paradigm, or more familiar with transactions, do consider the speed benefit that nontransactional tables can offer on the order of three to five times the speed of the fastest and most optimally tuned transactional tables. In situations where integrity is of highest importance, MySQL Server offers transaction-level reliability and integrity even for nontransactional tables. If you lock tables with *Note `LOCK TABLES': lock-tables, all updates stall until integrity checks are made. If you obtain a `READ LOCAL' lock (as opposed to a write lock) for a table that enables concurrent inserts at the end of the table, reads are permitted, as are inserts by other clients. The newly inserted records are not be seen by the client that has the read lock until it releases the lock. With *Note `INSERT DELAYED': insert-delayed, you can write inserts that go into a local queue until the locks are released, without having the client wait for the insert to complete. See *Note concurrent-inserts::, and *Note insert-delayed::. `Atomic,' in the sense that we mean it, is nothing magical. It only means that you can be sure that while each specific update is running, no other user can interfere with it, and there can never be an automatic rollback (which can happen with transactional tables if you are not very careful). MySQL Server also guarantees that there are no dirty reads. Following are some techniques for working with nontransactional tables: * Loops that need transactions normally can be coded with the help of *Note `LOCK TABLES': lock-tables, and you don't need cursors to update records on the fly. * To avoid using *Note `ROLLBACK': commit, you can employ the following strategy: 1. Use *Note `LOCK TABLES': lock-tables. to lock all the tables you want to access. 2. Test the conditions that must be true before performing the update. 3. Update if the conditions are satisfied. 4. Use *Note `UNLOCK TABLES': lock-tables. to release your locks. This is usually a much faster method than using transactions with possible rollbacks, although not always. The only situation this solution doesn't handle is when someone kills the threads in the middle of an update. In that case, all locks are released but some of the updates may not have been executed. * You can also use functions to update records in a single operation. You can get a very efficient application by using the following techniques: * Modify columns relative to their current value. * Update only those columns that actually have changed. For example, when we are updating customer information, we update only the customer data that has changed and test only that none of the changed data, or data that depends on the changed data, has changed compared to the original row. The test for changed data is done with the `WHERE' clause in the *Note `UPDATE': update. statement. If the record wasn't updated, we give the client a message: `Some of the data you have changed has been changed by another user.' Then we show the old row versus the new row in a window so that the user can decide which version of the customer record to use. This gives us something that is similar to column locking but is actually even better because we only update some of the columns, using values that are relative to their current values. This means that typical *Note `UPDATE': update. statements look something like these: UPDATE tablename SET pay_back=pay_back+125; UPDATE customer SET customer_date='current_date', address='new address', phone='new phone', money_owed_to_us=money_owed_to_us-125 WHERE customer_id=id AND address='old address' AND phone='old phone'; This is very efficient and works even if another client has changed the values in the `pay_back' or `money_owed_to_us' columns. * In many cases, users have wanted *Note `LOCK TABLES': lock-tables. or *Note `ROLLBACK': commit. for the purpose of managing unique identifiers. This can be handled much more efficiently without locking or rolling back by using an `AUTO_INCREMENT' column and either the `LAST_INSERT_ID()' SQL function or the *Note `mysql_insert_id()': mysql-insert-id. C API function. See *Note information-functions::, and *Note mysql-insert-id::. You can generally code around the need for row-level locking. Some situations really do need it, and `InnoDB' tables support row-level locking. Otherwise, with `MyISAM' tables, you can use a flag column in the table and do something like the following: UPDATE TBL_NAME SET row_flag=1 WHERE id=ID; MySQL returns `1' for the number of affected rows if the row was found and `row_flag' wasn't `1' in the original row. You can think of this as though MySQL Server changed the preceding statement to: UPDATE TBL_NAME SET row_flag=1 WHERE id=ID AND row_flag <> 1;  File: manual.info, Node: ansi-diff-foreign-keys, Next: ansi-diff-comments, Prev: ansi-diff-transactions, Up: differences-from-ansi 2.8.5.4 Foreign Keys .................... The `InnoDB' storage engine supports checking of foreign key constraints, including `CASCADE', `ON DELETE', and `ON UPDATE'. See *Note innodb-foreign-key-constraints::. For storage engines other than `InnoDB', MySQL Server parses the `FOREIGN KEY' syntax in *Note `CREATE TABLE': create-table. statements, but does not use or store it. In the future, the implementation will be extended to store this information in the table specification file so that it may be retrieved by *Note `mysqldump': mysqldump. and ODBC. At a later stage, foreign key constraints will be implemented for `MyISAM' tables as well. Foreign key enforcement offers several benefits to database developers: * Assuming proper design of the relationships, foreign key constraints make it more difficult for a programmer to introduce an inconsistency into the database. * Centralized checking of constraints by the database server makes it unnecessary to perform these checks on the application side. This eliminates the possibility that different applications may not all check the constraints in the same way. * Using cascading updates and deletes can simplify the application code. * Properly designed foreign key rules aid in documenting relationships between tables. Do keep in mind that these benefits come at the cost of additional overhead for the database server to perform the necessary checks. Additional checking by the server affects performance, which for some applications may be sufficiently undesirable as to be avoided if possible. (Some major commercial applications have coded the foreign key logic at the application level for this reason.) MySQL gives database developers the choice of which approach to use. If you don't need foreign keys and want to avoid the overhead associated with enforcing referential integrity, you can choose another storage engine instead, such as `MyISAM'. (For example, the `MyISAM' storage engine offers very fast performance for applications that perform only *Note `INSERT': insert. and *Note `SELECT': select. operations. In this case, the table has no holes in the middle and the inserts can be performed concurrently with retrievals. See *Note concurrent-inserts::.) If you choose not to take advantage of referential integrity checks, keep the following considerations in mind: * In the absence of server-side foreign key relationship checking, the application itself must handle relationship issues. For example, it must take care to insert rows into tables in the proper order, and to avoid creating orphaned child records. It must also be able to recover from errors that occur in the middle of multiple-record insert operations. * If `ON DELETE' is the only referential integrity capability an application needs, you can achieve a similar effect as of MySQL Server 4.0 by using multiple-table *Note `DELETE': delete. statements to delete rows from many tables with a single statement. See *Note delete::. * A workaround for the lack of `ON DELETE' is to add the appropriate *Note `DELETE': delete. statements to your application when you delete records from a table that has a foreign key. In practice, this is often as quick as using foreign keys and is more portable. Be aware that the use of foreign keys can sometimes lead to problems: * Foreign key support addresses many referential integrity issues, but it is still necessary to design key relationships carefully to avoid circular rules or incorrect combinations of cascading deletes. * It is not uncommon for a DBA to create a topology of relationships that makes it difficult to restore individual tables from a backup. (MySQL alleviates this difficulty by enabling you to temporarily disable foreign key checks when reloading a table that depends on other tables. See *Note innodb-foreign-key-constraints::. As of MySQL 4.1.1, *Note `mysqldump': mysqldump. generates dump files that take advantage of this capability automatically when they are reloaded.) Foreign keys in SQL are used to check and enforce referential integrity, not to join tables. If you want to get results from multiple tables from a *Note `SELECT': select. statement, you do this by performing a join between them: SELECT * FROM t1 INNER JOIN t2 ON t1.id = t2.id; See *Note join::, and *Note example-foreign-keys::. The `FOREIGN KEY' syntax without `ON DELETE ...' is often used by ODBC applications to produce automatic `WHERE' clauses.  File: manual.info, Node: ansi-diff-comments, Prev: ansi-diff-foreign-keys, Up: differences-from-ansi 2.8.5.5 '`--'' as the Start of a Comment ........................................ Standard SQL uses the C syntax `/* this is a comment */' for comments, and MySQL Server supports this syntax as well. MySQL also support extensions to this syntax that enable MySQL-specific SQL to be embedded in the comment, as described in *Note comments::. Standard SQL uses ``--'' as a start-comment sequence. MySQL Server uses ``#'' as the start comment character. MySQL Server 3.23.3 and up also supports a variant of the ``--'' comment style. That is, the ``--'' start-comment sequence must be followed by a space (or by a control character such as a newline). The space is required to prevent problems with automatically generated SQL queries that use constructs such as the following, where we automatically insert the value of the payment for `payment': UPDATE account SET credit=credit-payment Consider about what happens if `payment' has a negative value such as `-1': UPDATE account SET credit=credit--1 `credit--1' is a legal expression in SQL, but ``--'' is interpreted as the start of a comment, part of the expression is discarded. The result is a statement that has a completely different meaning than intended: UPDATE account SET credit=credit The statement produces no change in value at all. This illustrates that permitting comments to start with ``--'' can have serious consequences. Using our implementation requires a space following the ``--'' for it to be recognized as a start-comment sequence in MySQL Server 3.23.3 and newer. Therefore, `credit--1' is safe to use. Another safe feature is that the *Note `mysql': mysql. command-line client ignores lines that start with ``--''. The following information is relevant only if you are running a MySQL version earlier than 3.23.3: If you have an SQL script in a text file that contains ``--'' comments, you should use the *Note `replace': replace-utility. utility as follows to convert the comments to use ``#'' characters before executing the script: shell> replace " --" " #" < text-file-with-funny-comments.sql \ | mysql DB_NAME That is safer than executing the script in the usual way: shell> mysql DB_NAME < text-file-with-funny-comments.sql You can also edit the script file `in place' to change the ``--'' comments to ``#'' comments: shell> replace " --" " #" -- text-file-with-funny-comments.sql Change them back with this command: shell> replace " #" " --" -- text-file-with-funny-comments.sql See *Note replace-utility::.  File: manual.info, Node: constraints, Prev: differences-from-ansi, Up: compatibility 2.8.6 How MySQL Deals with Constraints -------------------------------------- * Menu: * constraint-primary-key:: `PRIMARY KEY' and `UNIQUE' Index Constraints * constraint-invalid-data:: Constraints on Invalid Data * constraint-enum:: `ENUM' and `SET' Constraints MySQL enables you to work both with transactional tables that permit rollback and with nontransactional tables that do not. Because of this, constraint handling is a bit different in MySQL than in other DBMSs. We must handle the case when you have inserted or updated a lot of rows in a nontransactional table for which changes cannot be rolled back when an error occurs. The basic philosophy is that MySQL Server tries to produce an error for anything that it can detect while parsing a statement to be executed, and tries to recover from any errors that occur while executing the statement. We do this in most cases, but not yet for all. The options MySQL has when an error occurs are to stop the statement in the middle or to recover as well as possible from the problem and continue. By default, the server follows the latter course. This means, for example, that the server may coerce illegal values to the closest legal values. Several SQL mode options are available to provide greater control over handling of bad data values and whether to continue statement execution or abort when errors occur. Using these options, you can configure MySQL Server to act in a more traditional fashion that is like other DBMSs that reject improper input. The SQL mode can be set globally at server startup to affect all clients. Individual clients can set the SQL mode at runtime, which enables each client to select the behavior most appropriate for its requirements. See *Note server-sql-mode::. The following sections describe how MySQL Server handles different types of constraints.  File: manual.info, Node: constraint-primary-key, Next: constraint-invalid-data, Prev: constraints, Up: constraints 2.8.6.1 `PRIMARY KEY' and `UNIQUE' Index Constraints .................................................... Normally, errors occurs for data-change statements (such as *Note `INSERT': insert. or *Note `UPDATE': update.) that would violate primary-key, unique-key, or foreign-key constraints. If you are using a transactional storage engine such as `InnoDB', MySQL automatically rolls back the statement. If you are using a nontransactional storage engine, MySQL stops processing the statement at the row for which the error occurred and leaves any remaining rows unprocessed. MySQL supports an `IGNORE' keyword for *Note `INSERT': insert, *Note `UPDATE': update, and so forth. If you use it, MySQL ignores primary-key or unique-key violations and continues processing with the next row. See the section for the statement that you are using (*Note insert::, *Note update::, and so forth). You can get information about the number of rows actually inserted or updated with the *Note `mysql_info()': mysql-info. C API function. You can also use the *Note `SHOW WARNINGS': show-warnings. statement. See *Note mysql-info::, and *Note show-warnings::. Currently, only `InnoDB' tables support foreign keys. See *Note innodb-foreign-key-constraints::.  File: manual.info, Node: constraint-invalid-data, Next: constraint-enum, Prev: constraint-primary-key, Up: constraints 2.8.6.2 Constraints on Invalid Data ................................... By default, MySQL is forgiving of illegal or improper data values and coerces them to legal values for data entry. However, you can change the server SQL mode to select more traditional treatment of bad values such that the server rejects them and aborts the statement in which they occur. See *Note server-sql-mode::. This section describes the default (forgiving) behavior of MySQL, as well as the strict SQL mode and how it differs. If you are not using strict mode, then whenever you insert an `incorrect' value into a column, such as a `NULL' into a `NOT NULL' column or a too-large numeric value into a numeric column, MySQL sets the column to the `best possible value' instead of producing an error: The following rules describe in more detail how this works: * If you try to store an out of range value into a numeric column, MySQL Server instead stores zero, the smallest possible value, or the largest possible value, whichever is closest to the invalid value. * For strings, MySQL stores either the empty string or as much of the string as can be stored in the column. * If you try to store a string that doesn't start with a number into a numeric column, MySQL Server stores 0. * Invalid values for *Note `ENUM': enum. and *Note `SET': set. columns are handled as described in *Note constraint-enum::. * MySQL enables you to store certain incorrect date values into *Note `DATE': datetime. and *Note `DATETIME': datetime. columns (such as `'2000-02-31'' or `'2000-02-00''). The idea is that it is not the job of the SQL server to validate dates. If MySQL can store a date value and retrieve exactly the same value, MySQL stores it as given. If the date is totally wrong (outside the server's ability to store it), the special `zero' date value `'0000-00-00'' is stored in the column instead. * If you try to store `NULL' into a column that doesn't take `NULL' values, an error occurs for single-row *Note `INSERT': insert. statements. For multiple-row *Note `INSERT': insert. statements or for *Note `INSERT INTO ... SELECT': insert-select. statements, MySQL Server stores the implicit default value for the column data type. In general, this is `0' for numeric types, the empty string (`''') for string types, and the `zero' value for date and time types. Implicit default values are discussed in *Note data-type-defaults::. * If an *Note `INSERT': insert. statement specifies no value for a column, MySQL inserts its default value if the column definition includes an explicit `DEFAULT' clause. If the definition has no such `DEFAULT' clause, MySQL inserts the implicit default value for the column data type. The reason for using the preceding rules in nonstrict mode is that we can't check these conditions until the statement has begun executing. We can't just roll back if we encounter a problem after updating a few rows, because the storage engine may not support rollback. The option of terminating the statement is not that good; in this case, the update would be `half done,' which is probably the worst possible scenario. In this case, it is better to `do the best you can' and then continue as if nothing happened. In MySQL 5.0.2 and up, you can select stricter treatment of input values by using the `STRICT_TRANS_TABLES' or `STRICT_ALL_TABLES' SQL modes: SET sql_mode = 'STRICT_TRANS_TABLES'; SET sql_mode = 'STRICT_ALL_TABLES'; `STRICT_TRANS_TABLES' enables strict mode for transactional storage engines, and also to some extent for nontransactional engines. It works like this: * For transactional storage engines, bad data values occurring anywhere in a statement cause the statement to abort and roll back. * For nontransactional storage engines, a statement aborts if the error occurs in the first row to be inserted or updated. (When the error occurs in the first row, the statement can be aborted to leave the table unchanged, just as for a transactional table.) Errors in rows after the first do not abort the statement, because the table has already been changed by the first row. Instead, bad data values are adjusted and result in warnings rather than errors. In other words, with `STRICT_TRANS_TABLES', a wrong value causes MySQL to roll back all updates done so far, if that can be done without changing the table. But once the table has been changed, further errors result in adjustments and warnings. For even stricter checking, enable `STRICT_ALL_TABLES'. This is the same as `STRICT_TRANS_TABLES' except that for nontransactional storage engines, errors abort the statement even for bad data in rows following the first row. This means that if an error occurs partway through a multiple-row insert or update for a nontransactional table, a partial update results. Earlier rows are inserted or updated, but those from the point of the error on are not. To avoid this for nontransactional tables, either use single-row statements or else use `STRICT_TRANS_TABLES' if conversion warnings rather than errors are acceptable. To avoid problems in the first place, do not use MySQL to check column content. It is safest (and often faster) to let the application ensure that it passes only legal values to the database. With either of the strict mode options, you can cause errors to be treated as warnings by using *Note `INSERT IGNORE': insert. or `UPDATE IGNORE' rather than *Note `INSERT': insert. or *Note `UPDATE': update. without `IGNORE'.  File: manual.info, Node: constraint-enum, Prev: constraint-invalid-data, Up: constraints 2.8.6.3 `ENUM' and `SET' Constraints .................................... *Note `ENUM': enum. and *Note `SET': set. columns provide an efficient way to define columns that can contain only a given set of values. See *Note enum::, and *Note set::. However, before MySQL 5.0.2, *Note `ENUM': enum. and *Note `SET': set. columns do not provide true constraints on entry of invalid data: * *Note `ENUM': enum. columns always have a default value. If you specify no default value, then it is `NULL' for columns that can have `NULL', otherwise it is the first enumeration value in the column definition. * If you insert an incorrect value into an *Note `ENUM': enum. column or if you force a value into an *Note `ENUM': enum. column with `IGNORE', it is set to the reserved enumeration value of `0', which is displayed as an empty string in string context. * If you insert an incorrect value into a *Note `SET': set. column, the incorrect value is ignored. For example, if the column can contain the values `'a'', `'b'', and `'c'', an attempt to assign `'a,x,b,y'' results in a value of `'a,b''. As of MySQL 5.0.2, you can configure the server to use strict SQL mode. See *Note server-sql-mode::. With strict mode enabled, the definition of a *Note `ENUM': enum. or *Note `SET': set. column does act as a constraint on values entered into the column. An error occurs for values that do not satisfy these conditions: * An *Note `ENUM': enum. value must be one of those listed in the column definition, or the internal numeric equivalent thereof. The value cannot be the error value (that is, 0 or the empty string). For a column defined as *Note `ENUM('a','b','c')': enum, values such as `''', `'d'', or `'ax'' are illegal and are rejected. * A *Note `SET': set. value must be the empty string or a value consisting only of the values listed in the column definition separated by commas. For a column defined as *Note `SET('a','b','c')': set, values such as `'d'' or `'a,b,c,d'' are illegal and are rejected. Errors for invalid values can be suppressed in strict mode if you use *Note `INSERT IGNORE': insert. or `UPDATE IGNORE'. In this case, a warning is generated rather than an error. For *Note `ENUM': enum, the value is inserted as the error member (`0'). For *Note `SET': set, the value is inserted as given except that any invalid substrings are deleted. For example, `'a,x,b,y'' results in a value of `'a,b''.  File: manual.info, Node: credits, Prev: compatibility, Up: introduction 2.9 Credits =========== * Menu: * contributors:: Contributors to MySQL * documenters-translators:: Documenters and translators * packages:: Packages that support MySQL * tools-used-to-create-mysql:: Tools that were used to create MySQL * supporters:: Supporters of MySQL The following sections list developers, contributors, and supporters that have helped to make MySQL what it is today.  File: manual.info, Node: contributors, Next: documenters-translators, Prev: credits, Up: credits 2.9.1 Contributors to MySQL --------------------------- Although Oracle Corporation and/or its affiliates own all copyrights in the `MySQL server' and the `MySQL manual', we wish to recognize those who have made contributions of one kind or another to the `MySQL distribution'. Contributors are listed here, in somewhat random order: * Gianmassimo Vigazzola or The initial port to Win32/NT. * Per Eric Olsson For constructive criticism and real testing of the dynamic record format. * Irena Pancirov Win32 port with Borland compiler. `mysqlshutdown.exe' and `mysqlwatch.exe'. * David J. Hughes For the effort to make a shareware SQL database. At TcX, the predecessor of MySQL AB, we started with `mSQL', but found that it couldn't satisfy our purposes so instead we wrote an SQL interface to our application builder Unireg. *Note `mysqladmin': mysqladmin. and *Note `mysql': mysql. client are programs that were largely influenced by their `mSQL' counterparts. We have put a lot of effort into making the MySQL syntax a superset of `mSQL'. Many of the API's ideas are borrowed from `mSQL' to make it easy to port free `mSQL' programs to the MySQL API. The MySQL software doesn't contain any code from `mSQL'. Two files in the distribution (`client/insert_test.c' and `client/select_test.c') are based on the corresponding (noncopyrighted) files in the `mSQL' distribution, but are modified as examples showing the changes necessary to convert code from `mSQL' to MySQL Server. (`mSQL' is copyrighted David J. Hughes.) * Patrick Lynch For helping us acquire http://www.mysql.com/. * Fred Lindberg For setting up qmail to handle the MySQL mailing list and for the incredible help we got in managing the MySQL mailing lists. * Igor Romanenko *Note `mysqldump': mysqldump. (previously `msqldump', but ported and enhanced by Monty). * Yuri Dario For keeping up and extending the MySQL OS/2 port. * Tim Bunce Author of *Note `mysqlhotcopy': mysqlhotcopy. * Zarko Mocnik Sorting for Slovenian language. * "TAMITO" The `_MB' character set macros and the ujis and sjis character sets. * Joshua Chamas Base for concurrent insert, extended date syntax, debugging on NT, and answering on the MySQL mailing list. * Yves Carlier *Note `mysqlaccess': mysqlaccess, a program to show the access rights for a user. * Rhys Jones (And GWE Technologies Limited) For one of the early JDBC drivers. * Dr Xiaokun Kelvin ZHU Further development of one of the early JDBC drivers and other MySQL-related Java tools. * James Cooper For setting up a searchable mailing list archive at his site. * Rick Mehalick For `xmysql', a graphical X client for MySQL Server. * Doug Sisk For providing RPM packages of MySQL for Red Hat Linux. * Diemand Alexander V. For providing RPM packages of MySQL for Red Hat Linux-Alpha. * Antoni Pamies Olive For providing RPM versions of a lot of MySQL clients for Intel and SPARC. * Jay Bloodworth For providing RPM versions for MySQL 3.21. * David Sacerdote Ideas for secure checking of DNS host names. * Wei-Jou Chen Some support for Chinese(BIG5) characters. * Wei He A lot of functionality for the Chinese(GBK) character set. * Jan Pazdziora Czech sorting order. * Zeev Suraski `FROM_UNIXTIME()' time formatting, `ENCRYPT()' functions, and `bison' advisor. Active mailing list member. * Luuk de Boer Ported (and extended) the benchmark suite to `DBI'/`DBD'. Have been of great help with `crash-me' and running benchmarks. Some new date functions. The *Note `mysql_setpermission': mysql-setpermission. script. * Alexis Mikhailov User-defined functions (UDFs); *Note `CREATE FUNCTION': create-function. and *Note `DROP FUNCTION': drop-function. * Andreas F. Bobak The `AGGREGATE' extension to user-defined functions. * Ross Wakelin Help to set up InstallShield for MySQL-Win32. * Jethro Wright III The `libmysql.dll' library. * James Pereria Mysqlmanager, a Win32 GUI tool for administering MySQL Servers. * Curt Sampson Porting of MIT-pthreads to NetBSD/Alpha and NetBSD 1.3/i386. * Martin Ramsch Examples in the MySQL Tutorial. * Steve Harvey For making *Note `mysqlaccess': mysqlaccess. more secure. * Konark IA-64 Centre of Persistent Systems Private Limited `http://www.pspl.co.in/konark/'. Help with the Win64 port of the MySQL server. * Albert Chin-A-Young. Configure updates for Tru64, large file support and better TCP wrappers support. * John Birrell Emulation of `pthread_mutex()' for OS/2. * Benjamin Pflugmann Extended `MERGE' tables to handle `INSERTS'. Active member on the MySQL mailing lists. * Jocelyn Fournier Excellent spotting and reporting innumerable bugs (especially in the MySQL 4.1 subquery code). * Marc Liyanage Maintaining the Mac OS X packages and providing invaluable feedback on how to create Mac OS X packages. * Robert Rutherford Providing invaluable information and feedback about the QNX port. * Previous developers of NDB Cluster Lots of people were involved in various ways summer students, master thesis students, employees. In total more than 100 people so too many to mention here. Notable name is Ataullah Dabaghi who up until 1999 contributed around a third of the code base. A special thanks also to developers of the AXE system which provided much of the architectural foundations for NDB Cluster with blocks, signals and crash tracing functionality. Also credit should be given to those who believed in the ideas enough to allocate of their budgets for its development from 1992 to present time. * Google Inc. We wish to recognize Google Inc. for contributions to the MySQL distribution: Mark Callaghan's SMP Performance patches and other patches. Other contributors, bugfinders, and testers: James H. Thompson, Maurizio Menghini, Wojciech Tryc, Luca Berra, Zarko Mocnik, Wim Bonis, Elmar Haneke, , , , Ted Deppner , Mike Simons, Jaakko Hyvatti. And lots of bug report/patches from the folks on the mailing list. A big tribute goes to those that help us answer questions on the MySQL mailing lists: * Daniel Koch Irix setup. * Luuk de Boer Benchmark questions. * Tim Sailer `DBD::mysql' questions. * Boyd Lynn Gerber SCO-related questions. * Richard Mehalick `xmysql'-related questions and basic installation questions. * Zeev Suraski Apache module configuration questions (log & auth), PHP-related questions, SQL syntax-related questions and other general questions. * Francesc Guasch General questions. * Jonathan J Smith Questions pertaining to OS-specifics with Linux, SQL syntax, and other things that might need some work. * David Sklar Using MySQL from PHP and Perl. * Alistair MacDonald Is flexible and can handle Linux and perhaps HP-UX. * John Lyon Questions about installing MySQL on Linux systems, using either `.rpm' files or compiling from source. * Lorvid Ltd. Simple billing/license/support/copyright issues. * Patrick Sherrill ODBC and VisualC++ interface questions. * Randy Harmon `DBD', Linux, some SQL syntax questions.  File: manual.info, Node: documenters-translators, Next: packages, Prev: contributors, Up: credits 2.9.2 Documenters and translators --------------------------------- The following people have helped us with writing the MySQL documentation and translating the documentation or error messages in MySQL. * Paul DuBois Ongoing help with making this manual correct and understandable. That includes rewriting Monty's and David's attempts at English into English as other people know it. * Kim Aldale Helped to rewrite Monty's and David's early attempts at English into English. * Michael J. Miller Jr. For the first MySQL manual. And a lot of spelling/language fixes for the FAQ (that turned into the MySQL manual a long time ago). * Yan Cailin First translator of the MySQL Reference Manual into simplified Chinese in early 2000 on which the Big5 and HK coded (`http://mysql.hitstar.com/') versions were based. Personal home page at linuxdb.yeah.net (http://linuxdb.yeah.net). * Jay Flaherty Big parts of the Perl `DBI'/`DBD' section in the manual. * Paul Southworth , Ray Loyzaga Proof-reading of the Reference Manual. * Therrien Gilbert , Jean-Marc Pouyot French error messages. * Petr Snajdr, Czech error messages. * Jaroslaw Lewandowski Polish error messages. * Miguel Angel Fernandez Roiz Spanish error messages. * Roy-Magne Mo Norwegian error messages and testing of MySQL 3.21.xx. * Timur I. Bakeyev Russian error messages. * & Filippo Grassilli Italian error messages. * Dirk Munzinger German error messages. * Billik Stefan Slovak error messages. * Stefan Saroiu Romanian error messages. * Peter Feher Hungarian error messages. * Roberto M. Serqueira Portuguese error messages. * Carsten H. Pedersen Danish error messages. * Arjen Lentz Dutch error messages, completing earlier partial translation (also work on consistency and spelling).  File: manual.info, Node: packages, Next: tools-used-to-create-mysql, Prev: documenters-translators, Up: credits 2.9.3 Packages that support MySQL --------------------------------- The following is a list of creators/maintainers of some of the most important API/packages/applications that a lot of people use with MySQL. We cannot list every possible package here because the list would then be way to hard to maintain. For other packages, please refer to the software portal at `http://solutions.mysql.com/software/'. * Tim Bunce, Alligator Descartes For the `DBD' (Perl) interface. * Andreas Koenig For the Perl interface for MySQL Server. * Jochen Wiedmann For maintaining the Perl `DBD::mysql' module. * Eugene Chan For porting PHP for MySQL Server. * Georg Richter MySQL 4.1 testing and bug hunting. New PHP 5.0 `mysqli' extension (API) for use with MySQL 4.1 and up. * Giovanni Maruzzelli For porting iODBC (Unix ODBC). * Xavier Leroy The author of LinuxThreads (used by the MySQL Server on Linux).  File: manual.info, Node: tools-used-to-create-mysql, Next: supporters, Prev: packages, Up: credits 2.9.4 Tools that were used to create MySQL ------------------------------------------ The following is a list of some of the tools we have used to create MySQL. We use this to express our thanks to those that has created them as without these we could not have made MySQL what it is today. * Free Software Foundation From whom we got an excellent compiler (`gcc'), an excellent debugger (`gdb' and the `libc' library (from which we have borrowed `strto.c' to get some code working in Linux). * Free Software Foundation & The XEmacs development team For a really great editor/environment. * Julian Seward Author of `valgrind', an excellent memory checker tool that has helped us find a lot of otherwise hard to find bugs in MySQL. * Dorothea Lu"tkehaus and Andreas Zeller For `DDD' (The Data Display Debugger) which is an excellent graphical front end to `gdb').  File: manual.info, Node: supporters, Prev: tools-used-to-create-mysql, Up: credits 2.9.5 Supporters of MySQL ------------------------- Although Oracle Corporation and/or its affiliates own all copyrights in the `MySQL server' and the `MySQL manual', we wish to recognize the following companies, which helped us finance the development of the `MySQL server', such as by paying us for developing a new feature or giving us hardware for development of the `MySQL server'. * VA Linux / Andover.net Funded replication. * NuSphere Editing of the MySQL manual. * Stork Design studio The MySQL Web site in use between 1998-2000. * Intel Contributed to development on Windows and Linux platforms. * Compaq Contributed to Development on Linux/Alpha. * SWSoft Development on the embedded *Note `mysqld': mysqld. version. * FutureQuest The `--skip-show-database' option.  File: manual.info, Node: installing, Next: tutorial, Prev: introduction, Up: Top 3 Installing and Upgrading MySQL ******************************** * Menu: * general-installation-issues:: General Installation Guidance * binary-installation:: Installing MySQL from Generic Binaries on Unix/Linux * windows-installation:: Installing MySQL on Microsoft Windows * macosx-installation:: Installing MySQL on Mac OS X * linux-installation:: Installing MySQL on Linux * solaris-installation:: Installing MySQL on Solaris and OpenSolaris * aix-installation:: Installing MySQL on IBM AIX * hpux-installation:: Installing MySQL on HP-UX * freebsd-installation:: Installing MySQL on FreeBSD * i5os-installation:: Installing MySQL on i5/OS * source-installation:: Installing MySQL from Source * postinstallation:: Postinstallation Setup and Testing * upgrading-downgrading:: Upgrading or Downgrading MySQL * environment-variables:: Environment Variables * perl-support:: Perl Installation Notes This chapter describes how to obtain and install MySQL. A summary of the procedure follows and later sections provide the details. If you plan to upgrade an existing version of MySQL to a newer version rather than install MySQL for the first time, see *Note upgrading::, for information about upgrade procedures and about issues that you should consider before upgrading. If you are interested in migrating to MySQL from another database system, you may wish to read *Note faqs-migration::, which contains answers to some common questions concerning migration issues. 1. *Determine whether MySQL runs and is supported on your platform.* Please note that not all platforms are equally suitable for running MySQL, and that not all platforms on which MySQL is known to run are officially supported by Oracle Corporation: 2. *Choose which distribution to install.* Several versions of MySQL are available, and most are available in several distribution formats. You can choose from pre-packaged distributions containing binary (precompiled) programs or source code. When in doubt, use a binary distribution. We also provide public access to our current source tree for those who want to see our most recent developments and help us test new code. To determine which version and type of distribution you should use, see *Note which-version::. 3. *Download the distribution that you want to install.* For instructions, see *Note getting-mysql::. To verify the integrity of the distribution, use the instructions in *Note verifying-package-integrity::. 4. *Install the distribution.* To install MySQL from a binary distribution, use the instructions in *Note binary-installation::. To install MySQL from a source distribution or from the current development source tree, use the instructions in *Note source-installation::. 5. *Perform any necessary postinstallation setup.* After installing MySQL, read *Note postinstallation::. This section contains important information about making sure the MySQL server is working properly. It also describes how to secure the initial MySQL user accounts, _which have no passwords_ until you assign passwords. The section applies whether you install MySQL using a binary or source distribution. 6. If you want to run the MySQL benchmark scripts, Perl support for MySQL must be available. See *Note perl-support::. Instructions for installing MySQL on different platforms and environments is available on a platform by platform basis: * *Unix, Linux, FreeBSD* For instructions on installing MySQL on most Linux and Unix platforms using a generic binary (for example, a `.tar.gz' package), see *Note binary-installation::. For information on building MySQL entirely from the source code distributions or the source code repositories, see *Note source-installation:: For specific platform help on installation, configuration, and building from source see the corresponding platform section: * Linux, including notes on distribution specific methods, see *Note linux-installation::. * Solaris and OpenSolaris, including PKG and IPS formats, see *Note solaris-installation::. * IBM AIX, see *Note solaris-installation::. * Hewlett-Packard HP-UX, including the DEPOT package format, see *Note hpux-installation::. * FreeBSD, see *Note freebsd-installation::. * *Microsoft Windows* For instructions on installing MySQL on Microsoft Windows, using either a Zipped binary or an MSI package, see *Note windows-installation::. For information on using the MySQL Server Instance Config Wizard, see *Note mysql-config-wizard::. For details and instructions on building MySQL from source code using Microsoft Visual Studio, see *Note windows-source-build::. * *Mac OS X* For installation on Mac OS X, including using both the binary package and native PKG formats, see *Note macosx-installation::. For information on making use of the MySQL Startup Item to automatically start and stop MySQL, see *Note macosx-installation-startupitem::. For information on the MySQL Preference Pane, see *Note macosx-installation-prefpane::. * *IBM i5/OS* For instructions on installing, starting, and stopping MySQL on i5/OS, see *Note i5os-installation::.  File: manual.info, Node: general-installation-issues, Next: binary-installation, Prev: installing, Up: installing 3.1 General Installation Guidance ================================= * Menu: * supported-os:: Operating Systems Supported by MySQL Community Server * which-version:: Choosing Which MySQL Distribution to Install * getting-mysql:: How to Get MySQL * verifying-package-integrity:: Verifying Package Integrity Using MD5 Checksums or `GnuPG' * installation-layouts:: Installation Layouts * compiler-characteristics:: Compiler-Specific Build Characteristics The immediately following sections contain the information necessary to choose, download, and verify your distribution. The instructions in later sections of the chapter describe how to install the distribution that you choose. For binary distributions, see the instructions at *Note binary-installation:: or the corresponding section for your platform if available. To build MySQL from source, use the instructions in *Note source-installation::.  File: manual.info, Node: supported-os, Next: which-version, Prev: general-installation-issues, Up: general-installation-issues 3.1.1 Operating Systems Supported by MySQL Community Server ----------------------------------------------------------- This section lists the operating systems on which MySQL Community Server is known to run. *Important*: Oracle Corporation does not necessarily provide official support for all the platforms listed in this section. For information about those platforms that are officially supported, see http://www.mysql.com/support/supportedplatforms.html on the MySQL Web site. We use GNU Autoconf, so it is possible to port MySQL to all modern systems that have a C++ compiler and a working implementation of POSIX threads. (Thread support is needed for the server. To compile only the client code, the only requirement is a C++ compiler.) MySQL has been reported to compile successfully on the following combinations of operating system and thread package. * AIX 4.x, 5.x with native threads. See *Note aix-installation::. AIX 5.3 should be upgraded to technology level 7 (5300-07). * FreeBSD 5.x and up with native threads. See *Note freebsd-installation::. * HP-UX 11.x with the native threads. See *Note hpux-installation::. * Linux. Builds on all recent Linux distributions based on the 2.6 kernel. See *Note linux-installation::. * Mac OS X. See *Note macosx-installation::. * Solaris 2.8 on SPARC and x86, including support for native threads. See *Note solaris-installation::. * Windows 2000, Windows XP, Windows Vista, Windows Server 2003, and Windows Server 2008. See *Note windows-installation::. MySQL has also been known to run on other systems in the past. See *Note general-installation-issues::. Some porting effort might be required for current versions of MySQL on these systems. Not all platforms are equally well-suited for running MySQL. How well a certain platform is suited for a high-load mission-critical MySQL server is determined by the following factors: * General stability of the thread library. A platform may have an excellent reputation otherwise, but MySQL is only as stable as the thread library it calls, even if everything else is perfect. * The capability of the kernel and the thread library to take advantage of symmetric multi-processor (SMP) systems. In other words, when a process creates a thread, it should be possible for that thread to run on a CPU different from the original process. * The capability of the kernel and the thread library to run many threads that acquire and release a mutex over a short critical region frequently without excessive context switches. If the implementation of `pthread_mutex_lock()' is too anxious to yield CPU time, this hurts MySQL tremendously. If this issue is not taken care of, adding extra CPUs actually makes MySQL slower. * General file system stability and performance. * Table size. If your tables are large, performance is affected by the ability of the file system to deal with large files and dealing with them efficiently. * Our level of expertise here at Oracle Corporation with the platform. If we know a platform well, we enable platform-specific optimizations and fixes at compile time. We can also provide advice on configuring your system optimally for MySQL. * The amount of testing we have done internally for similar configurations. * The number of users that have run MySQL successfully on the platform in similar configurations. If this number is high, the likelihood of encountering platform-specific surprises is much smaller.  File: manual.info, Node: which-version, Next: getting-mysql, Prev: supported-os, Up: general-installation-issues 3.1.2 Choosing Which MySQL Distribution to Install -------------------------------------------------- * Menu: * choosing-version:: Choosing Which Version of MySQL to Install * choosing-distribution-format:: Choosing a Distribution Format * many-versions:: How and When Updates Are Released When preparing to install MySQL, you should decide which version to use. MySQL development occurs in several release series, and you can pick the one that best fits your needs. After deciding which version to install, you can choose a distribution format. Releases are available in binary or source format.  File: manual.info, Node: choosing-version, Next: choosing-distribution-format, Prev: which-version, Up: which-version 3.1.2.1 Choosing Which Version of MySQL to Install .................................................. The first decision to make is whether you want to use a production (stable) release or a development release. In the MySQL development process, multiple release series co-exist, each at a different stage of maturity. * Production Releases * * MySQL 5.5: Latest General Availability (Production) release * MySQL 5.1: Previous stable (production-quality) release * MySQL 5.0: Older stable release nearing the end of the product lifecycle * Development Release * * MySQL 5.6: Current release under development (pre-Production) MySQL 4.1, 4.0, and 3.23 are old releases that are no longer supported. See http://www.mysql.com/about/legal/lifecycle/ for information about support policies and schedules. Normally, if you are beginning to use MySQL for the first time or trying to port it to some system for which there is no binary distribution, use the most recent General Availability series listed in the preceding descriptions. All MySQL releases, even those from development series, are checked with the MySQL benchmarks and an extensive test suite before being issued. If you are running an older system and want to upgrade, but do not want to take the chance of having a nonseamless upgrade, you should upgrade to the latest version in the same release series you are using (where only the last part of the version number is newer than yours). We have tried to fix only fatal bugs and make only small, relatively `safe' changes to that version. If you want to use new features not present in the production release series, you can use a version from a development series. Be aware that development releases are not as stable as production releases. We do not use a complete code freeze because this prevents us from making bugfixes and other fixes that must be done. We may add small things that should not affect anything that currently works in a production release. Naturally, relevant bugfixes from an earlier series propagate to later series. If you want to use the very latest sources containing all current patches and bugfixes, you can use one of our source code repositories (see *Note installing-development-tree::). These are not `releases' as such, but are available as previews of the code on which future releases are to be based. The naming scheme in MySQL 5.1 uses release names that consist of three numbers and a suffix; for example, *mysql-5.1.29-rc*. The numbers within the release name are interpreted as follows: * The first number (*5*) is the major version and describes the file format. All MySQL 5 releases have the same file format. * The second number (*1*) is the release level. Taken together, the major version and release level constitute the release series number. * The third number (*29*) is the version number within the release series. This is incremented for each new release. Usually you want the latest version for the series you have chosen. For each minor update, the last number in the version string is incremented. When there are major new features or minor incompatibilities with previous versions, the second number in the version string is incremented. When the file format changes, the first number is increased. Release names also include a suffix to indicates the stability level of the release. Releases within a series progress through a set of suffixes to indicate how the stability level improves. The possible suffixes are: * *alpha* indicates that the release is for preview purposes only. Known bugs should be documented in the News section (see *Note news::). Most alpha releases implement new commands and extensions. Active development that may involve major code changes can occur in an alpha release. However, we do conduct testing before issuing a release. * *beta* indicates that the release is appropriate for use with new development. Within beta releases, the features and compatibility should remain consistent. However, beta releases may contain numerous and major unaddressed bugs. All APIs, externally visible structures, and columns for SQL statements will not change during future beta, release candidate, or production releases. * *rc* indicates a Release Candidate. Release candidates are believed to be stable, having passed all of MySQL's internal testing, and with all known fatal runtime bugs fixed. However, the release has not been in widespread use long enough to know for sure that all bugs have been identified. Only minor fixes are added. (A release candidate is what formerly was known as a gamma release.) * If there is no suffix, it indicates that the release is a General Availability (GA) or Production release. GA releases are stable, having successfully passed through all earlier release stages and are believed to be reliable, free of serious bugs, and suitable for use in production systems. Only critical bugfixes are applied to the release. All releases of MySQL are run through our standard tests and benchmarks to ensure that they are relatively safe to use. Because the standard tests are extended over time to check for all previously found bugs, the test suite keeps getting better. All releases have been tested at least with these tools: * An internal test suite The `mysql-test' directory contains an extensive set of test cases. We run these tests for every server binary. See *Note mysql-test-suite::, for more information about this test suite. * The MySQL benchmark suite This suite runs a range of common queries. It is also a test to determine whether the latest batch of optimizations actually made the code faster. See *Note mysql-benchmarks::. We also perform additional integration and nonfunctional testing of the latest MySQL version in our internal production environment. Integration testing is done with different connectors, storage engines, replication modes, backup, partitioning, stored programs, and so forth in various combinations. Additional nonfunctional testing is done in areas of performance, concurrency, stress, high volume, upgrade and downgrade.  File: manual.info, Node: choosing-distribution-format, Next: many-versions, Prev: choosing-version, Up: which-version 3.1.2.2 Choosing a Distribution Format ...................................... After choosing which version of MySQL to install, you should decide whether to use a binary distribution or a source distribution. In most cases, you should probably use a binary distribution, if one exists for your platform. Binary distributions are available in native format for many platforms, such as RPM files for Linux or PKG package installers for Mac OS X or Solaris. Distributions also are available as Zip archives or compressed `tar' files. Reasons to choose a binary distribution include the following: * Binary distributions generally are easier to install than source distributions. * To satisfy different user requirements, we provide several servers in binary distributions. *Note `mysqld': mysqld. is an optimized server that is a smaller, faster binary. *Note `mysqld-debug': mysqld. is compiled with debugging support. Each of these servers is compiled from the same source distribution, though with different configuration options. All native MySQL clients can connect to servers from either MySQL version. Under some circumstances, you may be better off installing MySQL from a source distribution: * You want to install MySQL at some explicit location. The standard binary distributions are ready to run at any installation location, but you might require even more flexibility to place MySQL components where you want. * You want to configure *Note `mysqld': mysqld. to ensure that features are available that might not be included in the standard binary distributions. Here is a list of the most common extra options that you may want to use to ensure feature availability: * `--with-libwrap' * `--with-named-z-libs' (this is done for some of the binaries) * `--with-debug[=full]' * You want to configure *Note `mysqld': mysqld. without some features that are included in the standard binary distributions. For example, distributions normally are compiled with support for all character sets. If you want a smaller MySQL server, you can recompile it with support for only the character sets you need. * You want to use the latest sources from one of the Bazaar repositories to have access to all current bugfixes. For example, if you have found a bug and reported it to the MySQL development team, the bugfix is committed to the source repository and you can access it there. The bugfix does not appear in a release until a release actually is issued. * You want to read (or modify) the C and C++ code that makes up MySQL. For this purpose, you should get a source distribution, because the source code is always the ultimate manual. * Source distributions contain more tests and examples than binary distributions.  File: manual.info, Node: many-versions, Prev: choosing-distribution-format, Up: which-version 3.1.2.3 How and When Updates Are Released ......................................... MySQL is evolving quite rapidly and we want to share new developments with other MySQL users. We try to produce a new release whenever we have new and useful features that others also seem to have a need for. We also try to help users who request features that are easy to implement. We take note of what our licensed users want, and we especially take note of what our support customers want and try to help them in this regard. No one is _required_ to download a new release. The News section helps you determine whether the new release has something you really want. See *Note news::. We use the following policy when updating MySQL: * Enterprise Server releases are meant to appear every 18 months, supplemented by quarterly service packs and monthly rapid updates. Community Server releases are meant to appear 2 to 3 times per year. * Releases are issued within each series. For each release, the last number in the version is one more than the previous release within the same series. * Binary distributions for some platforms are made by us for major releases. Other people may make binary distributions for other systems, but probably less frequently. * We make fixes available as soon as we have identified and corrected small or noncritical but annoying bugs. The fixes are available in source form immediately from our public Bazaar repositories, and are included in the next release. * If by any chance a security vulnerability or critical bug is found in a release, our policy is to fix it in a new release as soon as possible. (We would like other companies to do this, too!)  File: manual.info, Node: getting-mysql, Next: verifying-package-integrity, Prev: which-version, Up: general-installation-issues 3.1.3 How to Get MySQL ---------------------- Check our downloads page at `http://dev.mysql.com/downloads/' for information about the current version of MySQL and for downloading instructions. For a complete up-to-date list of MySQL download mirror sites, see `http://dev.mysql.com/downloads/mirrors.html'. You can also find information there about becoming a MySQL mirror site and how to report a bad or out-of-date mirror. To obtain the latest development source, see *Note installing-development-tree::.  File: manual.info, Node: verifying-package-integrity, Next: installation-layouts, Prev: getting-mysql, Up: general-installation-issues 3.1.4 Verifying Package Integrity Using MD5 Checksums or `GnuPG' ---------------------------------------------------------------- * Menu: * verifying-md5-checksum:: Verifying the MD5 Checksum * checking-gpg-signature:: Signature Checking Using `GnuPG' * checking-rpm-signature:: Signature Checking Using `RPM' After you have downloaded the MySQL package that suits your needs and before you attempt to install it, you should make sure that it is intact and has not been tampered with. There are three means of integrity checking: * MD5 checksums * Cryptographic signatures using `GnuPG', the GNU Privacy Guard * For RPM packages, the built-in RPM integrity verification mechanism The following sections describe how to use these methods. If you notice that the MD5 checksum or GPG signatures do not match, first try to download the respective package one more time, perhaps from another mirror site. If you repeatedly cannot successfully verify the integrity of the package, please notify us about such incidents, including the full package name and the download site you have been using, at or . Do not report downloading problems using the bug-reporting system.  File: manual.info, Node: verifying-md5-checksum, Next: checking-gpg-signature, Prev: verifying-package-integrity, Up: verifying-package-integrity 3.1.4.1 Verifying the MD5 Checksum .................................. After you have downloaded a MySQL package, you should make sure that its MD5 checksum matches the one provided on the MySQL download pages. Each package has an individual checksum that you can verify with the following command, where PACKAGE_NAME is the name of the package you downloaded: shell> md5sum PACKAGE_NAME Example: shell> md5sum mysql-standard-5.1.59-linux-i686.tar.gz aaab65abbec64d5e907dcd41b8699945 mysql-standard-5.1.59-linux-i686.tar.gz You should verify that the resulting checksum (the string of hexadecimal digits) matches the one displayed on the download page immediately below the respective package. *Note*: Make sure to verify the checksum of the _archive file_ (for example, the `.zip' or `.tar.gz' file) and not of the files that are contained inside of the archive. Note that not all operating systems support the `md5sum' command. On some, it is simply called `md5', and others do not ship it at all. On Linux, it is part of the *GNU Text Utilities* package, which is available for a wide range of platforms. You can download the source code from `http://www.gnu.org/software/textutils/' as well. If you have OpenSSL installed, you can use the command `openssl md5 PACKAGE_NAME' instead. A Windows implementation of the `md5' command line utility is available from `http://www.fourmilab.ch/md5/'. `winMd5Sum' is a graphical MD5 checking tool that can be obtained from `http://www.nullriver.com/index/products/winmd5sum'.  File: manual.info, Node: checking-gpg-signature, Next: checking-rpm-signature, Prev: verifying-md5-checksum, Up: verifying-package-integrity 3.1.4.2 Signature Checking Using `GnuPG' ........................................ Another method of verifying the integrity and authenticity of a package is to use cryptographic signatures. This is more reliable than using MD5 checksums, but requires more work. We sign MySQL downloadable packages with `GnuPG' (GNU Privacy Guard). `GnuPG' is an Open Source alternative to the well-known Pretty Good Privacy (`PGP') by Phil Zimmermann. See `http://www.gnupg.org/' for more information about `GnuPG' and how to obtain and install it on your system. Most Linux distributions ship with `GnuPG' installed by default. For more information about `GnuPG', see `http://www.openpgp.org/'. To verify the signature for a specific package, you first need to obtain a copy of our public GPG build key, which you can download from `http://keyserver.pgp.com/'. The key that you want to obtain is named `build@mysql.com'. Alternatively, you can cut and paste the key directly from the following text: -----BEGIN PGP PUBLIC KEY BLOCK----- Version: GnuPG v1.4.5 (GNU/Linux) mQGiBD4+owwRBAC14GIfUfCyEDSIePvEW3SAFUdJBtoQHH/nJKZyQT7h9bPlUWC3 RODjQReyCITRrdwyrKUGku2FmeVGwn2u2WmDMNABLnpprWPkBdCk96+OmSLN9brZ fw2vOUgCmYv2hW0hyDHuvYlQA/BThQoADgj8AW6/0Lo7V1W9/8VuHP0gQwCgvzV3 BqOxRznNCRCRxAuAuVztHRcEAJooQK1+iSiunZMYD1WufeXfshc57S/+yeJkegNW hxwR9pRWVArNYJdDRT+rf2RUe3vpquKNQU/hnEIUHJRQqYHo8gTxvxXNQc7fJYLV K2HtkrPbP72vwsEKMYhhr0eKCbtLGfls9krjJ6sBgACyP/Vb7hiPwxh6rDZ7ITnE kYpXBACmWpP8NJTkamEnPCia2ZoOHODANwpUkP43I7jsDmgtobZX9qnrAXw+uNDI QJEXM6FSbi0LLtZciNlYsafwAPEOMDKpMqAK6IyisNtPvaLd8lH0bPAnWqcyefep rv0sxxqUEMcM3o7wwgfN83POkDasDbs3pjwPhxvhz6//62zQJ7Q7TXlTUUwgUGFj a2FnZSBzaWduaW5nIGtleSAod3d3Lm15c3FsLmNvbSkgPGJ1aWxkQG15c3FsLmNv bT6IXQQTEQIAHQULBwoDBAMVAwIDFgIBAheABQJLcC5lBQkQ8/JZAAoJEIxxjTtQ cuH1oD4AoIcOQ4EoGsZvy06D0Ei5vcsWEy8dAJ4g46i3WEcdSWxMhcBSsPz65sh5 lohMBBMRAgAMBQI+PqPRBYMJZgC7AAoJEElQ4SqycpHyJOEAn1mxHijft00bKXvu cSo/pECUmppiAJ41M9MRVj5VcdH/KN/KjRtW6tHFPYhMBBMRAgAMBQI+QoIDBYMJ YiKJAAoJELb1zU3GuiQ/lpEAoIhpp6BozKI8p6eaabzF5MlJH58pAKCu/ROofK8J Eg2aLos+5zEYrB/LsrkCDQQ+PqMdEAgA7+GJfxbMdY4wslPnjH9rF4N2qfWsEN/l xaZoJYc3a6M02WCnHl6ahT2/tBK2w1QI4YFteR47gCvtgb6O1JHffOo2HfLmRDRi Rjd1DTCHqeyX7CHhcghj/dNRlW2Z0l5QFEcmV9U0Vhp3aFfWC4Ujfs3LU+hkAWzE 7zaD5cH9J7yv/6xuZVw411x0h4UqsTcWMu0iM1BzELqX1DY7LwoPEb/O9Rkbf4fm Le11EzIaCa4PqARXQZc4dhSinMt6K3X4BrRsKTfozBu74F47D8Ilbf5vSYHbuE5p /1oIDznkg/p8kW+3FxuWrycciqFTcNz215yyX39LXFnlLzKUb/F5GwADBQf+Lwqq a8CGrRfsOAJxim63CHfty5mUc5rUSnTslGYEIOCR1BeQauyPZbPDsDD9MZ1ZaSaf anFvwFG6Llx9xkU7tzq+vKLoWkm4u5xf3vn55VjnSd1aQ9eQnUcXiL4cnBGoTbOW I39EcyzgslzBdC++MPjcQTcA7p6JUVsP6oAB3FQWg54tuUo0Ec8bsM8b3Ev42Lmu QT5NdKHGwHsXTPtl0klk4bQk4OajHsiy1BMahpT27jWjJlMiJc+IWJ0mghkKHt92 6s/ymfdf5HkdQ1cyvsz5tryVI3Fx78XeSYfQvuuwqp2H139pXGEkg0n6KdUOetdZ Whe70YGNPw1yjWJT1IhMBBgRAgAMBQI+PqMdBQkJZgGAAAoJEIxxjTtQcuH17p4A n3r1QpVC9yhnW2cSAjq+kr72GX0eAJ4295kl6NxYEuFApmr1+0uUq/SlsQ== =Mski -----END PGP PUBLIC KEY BLOCK----- To import the build key into your personal public GPG keyring, use `gpg --import'. For example, if you have saved the key in a file named `mysql_pubkey.asc', the import command looks like this: shell> gpg --import mysql_pubkey.asc gpg: key 5072E1F5: public key "MySQL Package signing key (www.mysql.com) " imported gpg: Total number processed: 1 gpg: imported: 1 gpg: no ultimately trusted keys found You can also download the key from the public keyserver using the public key id, `5072E1F5': shell> gpg --recv-keys 5072E1F5 gpg: requesting key 5072E1F5 from hkp server subkeys.pgp.net gpg: key 5072E1F5: "MySQL Package signing key (www.mysql.com) " 2 new signatures gpg: no ultimately trusted keys found gpg: Total number processed: 1 gpg: new signatures: 2 If you want to import the key into your RPM configuration to validate RPM install packages, you should be able to import the key directly: shell> rpm --import mysql_pubkey.asc If you experience problems, try exporting the key from `gpg' and importing: shell> gpg --export -a 5072e1f5 > 5072e1f5.asc shell> rpm --import 5072e1f5.asc Alternatively, `rpm' also supports loading the key directly from a URL, and you cas use this manual page: shell> rpm --import http://dev.mysql.com/doc/refman/5.1/en/checking-gpg-signature.html After you have downloaded and imported the public build key, download your desired MySQL package and the corresponding signature, which also is available from the download page. The signature file has the same name as the distribution file with an `.asc' extension, as shown by the examples in the following table. *MySQL Package and Signature Files* File Type File Name Distribution file `mysql-standard-5.1.59-linux-i686.tar.gz' Signature file `mysql-standard-5.1.59-linux-i686.tar.gz.asc' Make sure that both files are stored in the same directory and then run the following command to verify the signature for the distribution file: shell> gpg --verify PACKAGE_NAME.asc Example: shell> gpg --verify mysql-standard-5.1.59-linux-i686.tar.gz.asc gpg: Signature made Tue 12 Jul 2005 23:35:41 EST using DSA key ID 5072E1F5 gpg: Good signature from "MySQL Package signing key (www.mysql.com) " The `Good signature' message indicates that everything is all right. You can ignore any `insecure memory' warning you might obtain. See the GPG documentation for more information on how to work with public keys.  File: manual.info, Node: checking-rpm-signature, Prev: checking-gpg-signature, Up: verifying-package-integrity 3.1.4.3 Signature Checking Using `RPM' ...................................... For RPM packages, there is no separate signature. RPM packages have a built-in GPG signature and MD5 checksum. You can verify a package by running the following command: shell> rpm --checksig PACKAGE_NAME.rpm Example: shell> rpm --checksig MySQL-server-5.1.59-0.glibc23.i386.rpm MySQL-server-5.1.59-0.glibc23.i386.rpm: md5 gpg OK *Note*: If you are using RPM 4.1 and it complains about `(GPG) NOT OK (MISSING KEYS: GPG#5072e1f5)', even though you have imported the MySQL public build key into your own GPG keyring, you need to import the key into the RPM keyring first. RPM 4.1 no longer uses your personal GPG keyring (or GPG itself). Rather, RPM maintains a separate keyring because it is a system-wide application and a user's GPG public keyring is a user-specific file. To import the MySQL public key into the RPM keyring, first obtain the key as described in *Note checking-gpg-signature::. Then use `rpm --import' to import the key. For example, if you have saved the public key in a file named `mysql_pubkey.asc', import it using this command: shell> rpm --import mysql_pubkey.asc If you need to obtain the MySQL public key, see *Note checking-gpg-signature::.  File: manual.info, Node: installation-layouts, Next: compiler-characteristics, Prev: verifying-package-integrity, Up: general-installation-issues 3.1.5 Installation Layouts -------------------------- The installation layout differs for different installation types (for example, native packages, binary tarballs, and source tarballs), which can lead to confusion when managing different systems or using different installation sources. The individual layouts are given in the corresponding installation type or platform chapter, as described following. Note that the layout of installations from vendors other than Oracle may differ from these layouts. * *Note windows-installation-layout:: * *Note source-installation-layout:: * *Note binary-installation-layout:: * *Note mysql-installation-layout-linuxrpm:: * *Note mysql-installation-layout-macosx::  File: manual.info, Node: compiler-characteristics, Prev: installation-layouts, Up: general-installation-issues 3.1.6 Compiler-Specific Build Characteristics --------------------------------------------- In some cases, the compiler used to build MySQL affects the features available for use. The notes in this section apply for binary distributions provided by Oracle Corporation or that you compile yourself from source. *`icc' (Intel C++ Compiler) Builds* A server built with `icc' has these characteristics: * SSL support is not included. * `InnoDB Plugin' is not included.  File: manual.info, Node: binary-installation, Next: windows-installation, Prev: general-installation-issues, Up: installing 3.2 Installing MySQL from Generic Binaries on Unix/Linux ======================================================== Oracle provides a set of binary distributions of MySQL. These include binary distributions in the form of compressed `tar' files (files with a `.tar.gz' extension) for a number of platforms, as well as binaries in platform-specific package formats for selected platforms. This section covers the installation of MySQL from a compressed `tar' file binary distribution. For other platform-specific package formats, see the other platform-specific sections. For example, for Windows distributions, see *Note windows-installation::. To obtain MySQL, see *Note getting-mysql::. MySQL compressed `tar' file binary distributions have names of the form `mysql-VERSION-OS.tar.gz', where `VERSION' is a number (for example, `5.1.59'), and OS indicates the type of operating system for which the distribution is intended (for example, `pc-linux-i686' or `winx64'). To install MySQL from a compressed `tar' file binary distribution, your system must have GNU `gunzip' to uncompress the distribution and a reasonable `tar' to unpack it. If your `tar' program supports the `z' option, it can both uncompress and unpack the file. GNU `tar' is known to work. The standard `tar' provided with some operating systems is not able to unpack the long file names in the MySQL distribution. You should download and install GNU `tar', or if available, use a preinstalled version of GNU tar. Usually this is available as `gnutar', `gtar', or as `tar' within a GNU or Free Software directory, such as `/usr/sfw/bin' or `/usr/local/bin'. GNU `tar' is available from `http://www.gnu.org/software/tar/'. *Warning*: If you have previously installed MySQL using your operating system native package management system, such as `yum' or `apt-get', you may experience problems installing using a native binary. Make sure your previous MySQL previous installation has been removed entirely (using your package management system), and that any additional files, such as old versions of your data files, have also been removed. You should also check the existence of configuration files such as `/etc/my.cnf' or the `/etc/mysql' directory have been deleted. If you run into problems and need to file a bug report, please use the instructions in *Note bug-reports::. On Unix, to install a compressed `tar' file binary distribution, unpack it at the installation location you choose (typically `/usr/local/mysql'). This creates the directories shown in the following table. *MySQL Installation Layout for Generic Unix/Linux Binary Package* Directory Contents of Directory `bin' Client programs and the *Note `mysqld': mysqld. server `data' Log files, databases `docs' Manual in Info format `man' Unix manual pages `include' Include (header) files `lib' Libraries `scripts' *Note `mysql_install_db': mysql-install-db. `share' Miscellaneous support files, including error messages, sample configuration files, SQL for database installation `sql-bench' Benchmarks Debug versions of the *Note `mysqld': mysqld. binary are available as *Note `mysqld-debug': mysqld. To compile your own debug version of MySQL from a source distribution, use the appropriate configuration options to enable debugging support. For more information on compiling from source, see *Note source-installation::. To install and use a MySQL binary distribution, the basic command sequence looks like this: shell> groupadd mysql shell> useradd -r -g mysql mysql shell> cd /usr/local shell> tar zxvf /PATH/TO/MYSQL-VERSION-OS.tar.gz shell> ln -s FULL-PATH-TO-MYSQL-VERSION-OS mysql shell> cd mysql shell> chown -R mysql . shell> chgrp -R mysql . shell> scripts/mysql_install_db --user=mysql shell> chown -R root . shell> chown -R mysql data # Next command is optional shell> cp support-files/my-medium.cnf /etc/my.cnf shell> bin/mysqld_safe --user=mysql & # Next command is optional shell> cp support-files/mysql.server /etc/init.d/mysql.server A more detailed version of the preceding description for installing a binary distribution follows. *Note*: This procedure assumes that you have `root' (administrator) access to your system. Alternatively, you can prefix each command using the `sudo' (Linux) or `pfexec' (OpenSolaris) command. The procedure does not set up any passwords for MySQL accounts. After following the procedure, proceed to *Note postinstallation::. * Create a `mysql' User and Group * If your system does not already have a user and group for *Note `mysqld': mysqld. to run as, you may need to create one. The following commands add the `mysql' group and the `mysql' user. You might want to call the user and group something else instead of `mysql'. If so, substitute the appropriate name in the following instructions. The syntax for `useradd' and `groupadd' may differ slightly on different versions of Unix, or they may have different names such as `adduser' and `addgroup'. shell> groupadd mysql shell> useradd -r -g mysql mysql *Note*: Because the user is required only for ownership purposes, not login purposes, the `useradd' command uses the `-r' option to create a user that does not have login permissions to your server host. Omit this option to permit logins for the user (or if your `useradd' does not support the option). * Obtain and Unpack the Distribution * Pick the directory under which you want to unpack the distribution and change location into it. The example here unpacks the distribution under `/usr/local'. The instructions, therefore, assume that you have permission to create files and directories in `/usr/local'. If that directory is protected, you must perform the installation as `root'. shell> cd /usr/local Obtain a distribution file using the instructions in *Note getting-mysql::. For a given release, binary distributions for all platforms are built from the same MySQL source distribution. Unpack the distribution, which creates the installation directory. Then create a symbolic link to that directory. `tar' can uncompress and unpack the distribution if it has `z' option support: shell> tar zxvf /PATH/TO/MYSQL-VERSION-OS.tar.gz shell> ln -s FULL-PATH-TO-MYSQL-VERSION-OS mysql The `tar' command creates a directory named `mysql-VERSION-OS'. The `ln' command makes a symbolic link to that directory. This enables you to refer more easily to the installation directory as `/usr/local/mysql'. If your `tar' does not have `z' option support, use `gunzip' to unpack the distribution and `tar' to unpack it. Replace the preceding `tar' command with the following alternative command to uncompress and extract the distribution: shell> gunzip < /PATH/TO/MYSQL-VERSION-OS.tar.gz | tar xvf - * Perform Postinstallation Setup * The remainder of the installation process involves setting up the configuration file, creating the core databases, and starting the MySQL server. For instructions, see *Note postinstallation::. *Note*: The accounts that are listed in the MySQL grant tables initially have no passwords. After starting the server, you should set up passwords for them using the instructions in *Note postinstallation::.  File: manual.info, Node: windows-installation, Next: macosx-installation, Prev: binary-installation, Up: installing 3.3 Installing MySQL on Microsoft Windows ========================================= * Menu: * windows-installation-layout:: MySQL Installation Layout on Microsoft Windows * windows-choosing-package:: Choosing the Installation Package for Microsoft Windows * windows-using-installer:: Installing MySQL on Microsoft Windows Using an MSI Package * mysql-config-wizard:: Using the MySQL Server Instance Config Wizard * windows-install-archive:: Installing MySQL on Microsoft Windows Using a `noinstall' Zip Archive * windows-troubleshooting:: Troubleshooting a Microsoft Windows MySQL Server Installation * windows-upgrading:: Upgrading MySQL Server on Microsoft Windows * windows-postinstallation:: MySQL Server on Microsoft Windows Postinstallation Procedures MySQL for Microsoft Windows is available in a number of different forms. A Microsoft Windows operating system such as Windows 2000, Windows XP, Windows Vista, Windows 7, Windows Server 2003, or Windows Server 2008. Both 32-bit and 64-bit versions are supported. In addition to running MySQL as a standard application, you can also run the MySQL server as a Windows service. By using a service you can monitor and control the operation of the server through the standard Windows service management tools. For more information, see *Note windows-start-service::. Generally, you should install MySQL on Windows using an account that has administrator rights. Otherwise, you may encounter problems with certain operations such as editing the `PATH' environment variable or accessing the `Service Control Manager'. Once installed, MySQL does not need to be executed using a user with Administrator privileges. For a list of limitations within the Windows version of MySQL, see *Note limits-windows::. In addition to the MySQL Server package, you may need or want additional components to use MySQL with your application or development environment. These include, but are not limited to: * If you plan to connect to the MySQL server using ODBC, you need a Connector/ODBC driver. For more information, including installation and configuration instructions, see *Note connector-odbc::. * If you plan to use MySQL server with .NET applications, you need the Connector/NET driver. For more information, including installation and configuration instructions, see *Note connector-net::. MySQL distributions for Windows can be downloaded from `http://dev.mysql.com/downloads/'. See *Note getting-mysql::. MySQL for Windows is available in several distribution formats, detailed below. Generally speaking, you should use a binary distribution that includes an installer. It is simpler to use than the others, and you need no additional tools to get MySQL up and running. The installer for the Windows version of MySQL, combined with a GUI Config Wizard, automatically installs MySQL, creates an option file, starts the server, and secures the default user accounts. * Binary installer distribution. The installable distribution comes packaged as a Microsoft Windows Installer (MSI) package that you can install manually or automatically on your systems. Two formats are available, an essentials package that contains all the files you need to install and configure MySQL, but no additional components, and a complete package that includes MySQL, configuration tools, benchmarks and other components. For more information on the specific differences, see *Note windows-choosing-package:: For instructions on installing MySQL using one of the MSI installation packages, see *Note windows-using-installer::. * Standard binary distribution format packaged as a Zip file containing all of the necessary files that you unpack into your chosen location. This package contains all of the files in the full Windows MSI Installer package, but does not including an installation program. For instructions on installing MySQL using the Zip file, see *Note windows-install-archive::. * The source distribution contains all the code and support files for building the executables using the Visual Studio compiler system. For instructions on building MySQL from source on Windows, see *Note windows-source-build::. *MySQL on Windows considerations:* * *Large Table Support* If you need tables with a size larger than 4GB, install MySQL on an NTFS or newer file system. Do not forget to use `MAX_ROWS' and `AVG_ROW_LENGTH' when you create tables. See *Note create-table::. * *MySQL and Virus Checking Software* Using virus scanning software such as Norton/Symantec Anti-Virus on directories containing MySQL data and temporary tables can cause issues, both in terms of the performance of MySQL and the virus-scanning software mis-identifying the contents of the files as containing spam. This is because of the fingerprinting mechanism used by the virus scanning software, and the way in which MySQL rapidly updates different files, which may be identified as a potential security risk. After installing MySQL Server, it is recommended that you disable virus scanning on the main directory (`datadir') being used to store your MySQL table data. There is usually a system built into the virus scanning software to permit certain directories to be specifically ignored during virus scanning. In addition, by default, MySQL creates temporary files in the standard Windows temporary directory. To prevent the temporary files also being scanned, you should configure a separate temporary directory for MySQL temporary files and add this to the virus scanning exclusion list. To do this, add a configuration option for the `tmpdir' parameter to your `my.ini' configuration file. For more information, see *Note windows-create-option-file::.  File: manual.info, Node: windows-installation-layout, Next: windows-choosing-package, Prev: windows-installation, Up: windows-installation 3.3.1 MySQL Installation Layout on Microsoft Windows ---------------------------------------------------- For MySQL 5.1 on Windows, the default installation directory is `C:\Program Files\MySQL\MySQL Server 5.1'. Some Windows users prefer to install in `C:\mysql', the directory that formerly was used as the default. However, the layout of the subdirectories remains the same. For MySQL 5.1.23 and earlier, all of the files are located within the parent directory, using the structure shown in the following table. *Installation Layout for Windows Using MySQL 5.1.23 and Earlier* Directory Contents of Directory `bin' Client programs and the *Note `mysqld': mysqld. server `data' Log files, databases `examples' Example programs and scripts `include' Include (header) files `lib' Libraries `scripts' Utility scripts `share' Miscellaneous support files, including error messages, character set files, sample configuration files, SQL for database installation For MySQL 5.1.24 and later, the default location of data directory was changed. The remainder of the directory structure remains the same. *Installation Layout for Windows Using MySQL 5.1.24 and later* Directory Contents of Directory `bin' Client programs and the *Note `mysqld': mysqld. server `C:\Documents and Log files, databases (Windows XP, Windows Settings\All Server 2003) Users\Application Data\MySQL' `C:\ProgramData\MySQL' Log files, databases (Windows 7, Windows Server 2008) `Docs' Manual in CHM format `examples' Example programs and scripts `include' Include (header) files `lib' Libraries `scripts' Utility scripts `share' Miscellaneous support files, including error messages, character set files, sample configuration files, SQL for database installation  File: manual.info, Node: windows-choosing-package, Next: windows-using-installer, Prev: windows-installation-layout, Up: windows-installation 3.3.2 Choosing the Installation Package for Microsoft Windows ------------------------------------------------------------- For MySQL 5.1, there are three installation package formats to choose from when installing MySQL on Windows: *Microsoft Windows MySQL Installation package comparison* Packaging Feature Essentials Complete Zip (No-install) Installer Yes Yes No Directory-only MySQL Server Instance Config Yes Yes No Wizard Test Suite No Yes Yes MySQL Server Yes Yes Yes MySQL Client Programs Yes Yes Yes C Headers/Libraries Yes Yes Yes Embedded Server No Optional Yes Scripts and Examples No Optional Yes In the above table: * _Yes_ indiciates that the component is installed by default. * _No_ indicates that the component is not installed or included. * _Optional_ indicates that the component is included with the package, but not installed unless explicitly requested using the Custom installation mode. The workflow for installing using the MSI installer is shown below: FIGURE GOES HERE: Installation Workflow for Windows using MSI The workflow for installing using the MSI installer is shown below: FIGURE GOES HERE: Installation Workflow for Windows using Zip *Note*: For the Essentials and Complete packages in the MSI installer, you can select individual components to be installed by using the Custom mode, including disable the components confiurated for installation by default. Full details on the components are suggested uses are provided below for reference: * *Windows Essentials*: This package has a file name similar to `mysql-essential-5.1.59-win32.msi' and is supplied as a Microsoft Installer (MSI) package. The package includes the minimum set of files needed to install MySQL on Windows, including the MySQL Server Instance Config Wizard. This package does not include optional components such as the embedded server, developer headers and libraries or benchmark suite. To install using this package, see *Note windows-using-installer::. * *Windows MSI Installer (Complete)*: This package has a file name similar to `mysql-5.1.59-win32.msi' and contains all files needed for a complete Windows installation, including the MySQL Server Instance Config Wizard. This package includes optional components such as the embedded server and benchmark suite. To install using this package, see *Note windows-using-installer::. * *Without installer*: This package has a file name similar to `mysql-noinstall-5.1.59-win32.zip' and contains all the files found in the Complete install package, with the exception of the MySQL Server Instance Config Wizard. This package does not include an automated installer, and must be manually installed and configured. The Essentials package is recommended for most users. Both the Essentials and Complete distributions are available as an `.msi' file for use with the Windows Installer. The Noinstall distribution is packaged as a Zip archive. To use a Zip archive, you must have a tool that can unpack `.zip' files. When using the MSI installers you can automate the installation process. For more information, see *Note windows-installer-msi-quiet::. To automate the creation of a MySQL instance, see *Note mysql-config-wizard-cmdline::. Your choice of install package affects the installation process you must follow. If you choose to install either an Essentials or Complete install package, see *Note windows-using-installer::. If you choose to install a Noinstall archive, see *Note windows-install-archive::.  File: manual.info, Node: windows-using-installer, Next: mysql-config-wizard, Prev: windows-choosing-package, Up: windows-installation 3.3.3 Installing MySQL on Microsoft Windows Using an MSI Package ---------------------------------------------------------------- * Menu: * windows-install-wizard:: Using the MySQL Installation Wizard for Microsoft Windows * windows-installer-msi-quiet:: Automating MySQL Installation on Microsoft Windows using the MSI Package * windows-installer-uninstalling:: Removing MySQL When Installed from the MSI Package The MSI package is designed to install and configure MySQL in such a way that you can immediately get started using MySQL. The MySQL Installation Wizard and MySQL Configuration Wizard are available in the Essentials and Complete install packages. They are recommended for most standard MySQL installations. Exceptions include users who need to install multiple instances of MySQL on a single server host and advanced users who want complete control of server configuration. * For information on installing using the GUI MSI installer process, see *Note windows-install-wizard::. * For information on installing using the command line using the MSI package, see *Note windows-installer-msi-quiet::. * If you have previously installed MySQL using the MSI package and want to remove MySQL, see *Note windows-installer-uninstalling::. The workflow sequence for using the installer is shown in the figure below: FIGURE GOES HERE: Installation Workflow for Windows using MSI Installer *Note*: Microsoft Windows XP and later include a firewall which specifically blocks ports. If you plan on using MySQL through a network port then you should open and create an exception for this port before performing the installation. To check and if necessary add an exception to the firewall settings: 1. First ensure that you are logged in as an Administrator or a user with Administrator privileges. 2. Go to the `Control Panel', and double click the `Windows Firewall' icon. 3. Choose the `Allow a program through Windows Firewall' option and click the `Add port' button. 4. Enter `MySQL' into the `Name' text box and `3306' (or the port of your choice) into the `Port number' text box. 5. Also ensure that the `TCP' protocol radio button is selected. 6. If you wish, you can also limit access to the MySQL server by choosing the `Change scope' button. 7. Confirm your choices by clicking the `OK' button. Additionally, when running the MySQL Installation Wizard on Windows Vista or newer, ensure that you are logged in as a user with administrative rights. *Note*: When using Windows Vista or newer, you may want to disable User Account Control (UAC) before performing the installation. If you do not do so, then MySQL may be identified as a security risk, which will mean that you need to enable MySQL. You can disable the security checking by following these instructions: 1. Open `Control Panel'. 2. Under the `User Accounts and Family Safety', select `Add or remove user accounts.' 3. Click the `Got to the main User Accounts page' link. 4. Click on `Turn User Account Control on or off'. You may be prompted to provide permission to change this setting. Click `Continue'. 5. Deselect or uncheck the check box next to `Use User Account Control (UAC) to help protect your computer'. Click `OK' to save the setting. You will need to restart to complete the process. Click `Restart Now' to reboot the machine and apply the changes. You can then follow the instructions below for installing Windows.  File: manual.info, Node: windows-install-wizard, Next: windows-installer-msi-quiet, Prev: windows-using-installer, Up: windows-using-installer 3.3.3.1 Using the MySQL Installation Wizard for Microsoft Windows ................................................................. * Menu: * mysql-install-wizard-starting:: MySQL Installation Wizard: Downloading and Starting * mysql-install-wizard-install-type:: MySQL Installation Wizard: Choosing an Install Type * mysql-install-wizard-custom-install:: MySQL Installation Wizard: The Custom Install Dialog * mysql-install-wizard-confirmation-dialog:: MySQL Installation Wizard: The Confirmation Dialog * mysql-install-wizard-changes:: MySQL Installation Wizard: Changes Made * mysql-install-wizard-upgrading:: MySQL Installation Wizard: Upgrading MySQL MySQL Installation Wizard is an installer for the MySQL server that uses the latest installer technologies for Microsoft Windows. The MySQL Installation Wizard, in combination with the MySQL Config Wizard, enables a user to install and configure a MySQL server that is ready for use immediately after installation. The MySQL Installation Wizard uses the standard Microsoft Installer Engine (MSI) system is the standard installer for all MySQL server distributions. See *Note mysql-install-wizard-upgrading::, for more information on upgrading from a previous version. If you are upgrading an installation from MySQL 5.1.31 or earlier to MySQL 5.1.32 or later, read the notes provided in *Note mysql-install-wizard-upgrading::. The Microsoft Windows Installer Engine was updated with the release of Windows XP; those using a previous version of Windows can reference this Microsoft Knowledge Base article (http://support.microsoft.com/default.aspx?scid=kb;EN-US;292539) for information on upgrading to the latest version of the Windows Installer Engine. In addition, Microsoft has introduced the WiX (Windows Installer XML) toolkit. This is the first highly acknowledged Open Source project from Microsoft. We have switched to WiX because it is an Open Source project and it enables us to handle the complete Windows installation process in a flexible manner using scripts. Improving the MySQL Installation Wizard depends on the support and feedback of users like you. If you find that the MySQL Installation Wizard is lacking some feature important to you, or if you discover a bug, please report it in our bugs database using the instructions given in *Note bug-reports::.  File: manual.info, Node: mysql-install-wizard-starting, Next: mysql-install-wizard-install-type, Prev: windows-install-wizard, Up: windows-install-wizard 3.3.3.2 MySQL Installation Wizard: Downloading and Starting ........................................................... The MySQL installation packages can be downloaded from `http://dev.mysql.com/downloads/'. If the package you download is contained within a Zip archive, you need to extract the archive first. The process for starting the wizard depends on the contents of the installation package you download. If there is a `setup.exe' file present, double-click it to start the installation process. If there is an `.msi' file present, double-click it to start the installation process.  File: manual.info, Node: mysql-install-wizard-install-type, Next: mysql-install-wizard-custom-install, Prev: mysql-install-wizard-starting, Up: windows-install-wizard 3.3.3.3 MySQL Installation Wizard: Choosing an Install Type ........................................................... There are three installation types available: *Typical*, *Complete*, and *Custom*. The *Typical* installation type installs the MySQL server, the *Note `mysql': mysql. command-line client, and the command-line utilities. The command-line clients and utilities include *Note `mysqldump': mysqldump, *Note `myisamchk': myisamchk, and several other tools to help you manage the MySQL server. The *Complete* installation type installs all components included in the installation package. The full installation package includes components such as the embedded server library, the benchmark suite, support scripts, and documentation. The *Custom* installation type gives you complete control over which packages you wish to install and the installation path that is used. See *Note mysql-install-wizard-custom-install::, for more information on performing a custom install. If you choose the *Typical* or *Complete* installation types and click the `Next' button, you advance to the confirmation screen to verify your choices and begin the installation. If you choose the *Custom* installation type and click the `Next' button, you advance to the custom installation dialog, described in *Note mysql-install-wizard-custom-install::.  File: manual.info, Node: mysql-install-wizard-custom-install, Next: mysql-install-wizard-confirmation-dialog, Prev: mysql-install-wizard-install-type, Up: windows-install-wizard 3.3.3.4 MySQL Installation Wizard: The Custom Install Dialog ............................................................ If you wish to change the installation path or the specific components that are installed by the MySQL Installation Wizard, choose the *Custom* installation type. A tree view on the left side of the custom install dialog lists all available components. Components that are not installed have a red `X' icon; components that are installed have a gray icon. To change whether a component is installed, click that component's icon and choose a new option from the drop-down list that appears. You can change the default installation path by clicking the `Change...' button to the right of the displayed installation path. After choosing your installation components and installation path, click the `Next' button to advance to the confirmation dialog.  File: manual.info, Node: mysql-install-wizard-confirmation-dialog, Next: mysql-install-wizard-changes, Prev: mysql-install-wizard-custom-install, Up: windows-install-wizard 3.3.3.5 MySQL Installation Wizard: The Confirmation Dialog .......................................................... Once you choose an installation type and optionally choose your installation components, you advance to the confirmation dialog. Your installation type and installation path are displayed for you to review. To install MySQL if you are satisfied with your settings, click the `Install' button. To change your settings, click the `Back' button. To exit the MySQL Installation Wizard without installing MySQL, click the `Cancel' button. In MySQL 5.1.47 and earlier, after installation is complete, you have the option of registering with the MySQL web site. Registration gives you access to post in the MySQL forums at forums.mysql.com (http://forums.mysql.com), along with the ability to report bugs at bugs.mysql.com (http://bugs.mysql.com) and to subscribe to our newsletter. The final screen of the installer provides a summary of the installation and gives you the option to launch the MySQL Config Wizard, which you can use to create a configuration file, install the MySQL service, and configure security settings.  File: manual.info, Node: mysql-install-wizard-changes, Next: mysql-install-wizard-upgrading, Prev: mysql-install-wizard-confirmation-dialog, Up: windows-install-wizard 3.3.3.6 MySQL Installation Wizard: Changes Made ............................................... Once you click the `Install' button, the MySQL Installation Wizard begins the installation process and makes certain changes to your system which are described in the sections that follow. *Changes to the Registry* The MySQL Installation Wizard creates one Windows registry key in a typical install situation, located in `HKEY_LOCAL_MACHINE\SOFTWARE\MySQL AB'. For 64-bit Windows, the registry location is `HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\MYSQL AB'. A server version specific entry will be created for each major version of MySQL that you install. The MySQL Installation Wizard creates a key named after the major version of the server that is being installed, such as `MySQL Server 5.1'. It contains two string values, `Location' and `Version'. The `Location' string contains the path to the installation directory. In a default installation it contains `C:\Program Files\MySQL\MySQL Server 5.1\'. The `Version' string contains the release number. For example, for an installation of MySQL Server 5.1.59, the key contains a value of `5.1.59'. These registry keys are used to help external tools identify the installed location of the MySQL server, preventing a complete scan of the hard-disk to determine the installation path of the MySQL server. The registry keys are not required to run the server, and if you install MySQL using the `noinstall' Zip archive, the registry keys are not created. *Changes to the Start Menu* The MySQL Installation Wizard creates a new entry in the Windows `Start' menu under a common MySQL menu heading named after the major version of MySQL that you have installed. For example, if you install MySQL 5.1, the MySQL Installation Wizard creates a `MySQL Server 5.1' section in the `Start' menu. The following entries are created within the new `Start' menu section: * `MySQL Command Line Client': This is a shortcut to the *Note `mysql': mysql. command-line client and is configured to connect as the `root' user. The shortcut prompts for a `root' user password when you connect. * `MySQL Server Instance Config Wizard': This is a shortcut to the MySQL Config Wizard. Use this shortcut to configure a newly installed server, or to reconfigure an existing server. * `MySQL Documentation': This is a link to the MySQL server documentation that is stored locally in the MySQL server installation directory. This option is not available when the MySQL server is installed using the Essentials installation package. *Changes to the File System* The MySQL Installation Wizard by default installs the MySQL 5.1 server to `C:\PROGRAM FILES\MySQL\MySQL Server 5.1', where PROGRAM FILES is the default location for applications in your system, and 5.1 is the major version of your MySQL server. This is the recommended location for the MySQL server, replacing the former default location `C:\mysql'. By default, all MySQL applications are stored in a common directory at `C:\PROGRAM FILES\MySQL', where PROGRAM FILES is the default location for applications in your Windows installation. A typical MySQL installation on a developer machine might look like this: C:\Program Files\MySQL\MySQL Server 5.1 C:\Program Files\MySQL\MySQL Workbench 5.1 OSS This approach makes it easier to manage and maintain all MySQL applications installed on a particular system. In MySQL 5.1.23 and earlier, the default location for the data files used by MySQL is located within the corresponding MySQL Server installation directory. For MySQL 5.1.24 and later, the default location of the data directory is the `AppData' directory configured for the user that installed the MySQL application.  File: manual.info, Node: mysql-install-wizard-upgrading, Prev: mysql-install-wizard-changes, Up: windows-install-wizard 3.3.3.7 MySQL Installation Wizard: Upgrading MySQL .................................................. The MySQL Installation Wizard can perform server upgrades automatically using the upgrade capabilities of MSI. That means you do not need to remove a previous installation manually before installing a new release. The installer automatically shuts down and removes the previous MySQL service before installing the new version. Automatic upgrades are available only when upgrading between installations that have the same major and minor version numbers. For example, you can upgrade automatically from MySQL 5.1.5 to MySQL 5.1.6, but not from MySQL 5.0 to MySQL 5.1. In MySQL 5.1.32 and later, the `EXE' version of the MSI installer packages were removed. When upgrading an existing MySQL installation from the old EXE based installer to the MSI based installer, please keep the following notes in mind: * The MSI installer will not identify an existing installation that was installed using the old EXE installer. This means that the installer will not stop the existing server, or detect that the existing password is required before installing the new version. To work around this: 1. Stop the current server manually using `net stop' or `mysqladmin shutdown'. 2. Remove the existing installation manually by using the `Add/Remove Programs' control panel. This will keep the existing configuration and data files, as these are not removed automatically. 3. Install the new version of MySQL using the MSI installer. When running the installation, skip updating the security by deselecting the check box on the security screen. 4. Complete the installation, and then start the server again. You should be able to login with your existing user and password credentials. * You can only upgrade the version and release using the MSI installer. For example, you can upgrade an open source installation with an open source installer. You cannot upgrade an open source installation using the enterprise installer. See *Note windows-upgrading::.  File: manual.info, Node: windows-installer-msi-quiet, Next: windows-installer-uninstalling, Prev: windows-install-wizard, Up: windows-using-installer 3.3.3.8 Automating MySQL Installation on Microsoft Windows using the MSI Package ................................................................................ The Microsoft Installer (MSI) supports a both a _quiet_ and a _passive_ mode that can be used to install MySQL automatically without requiring intervention. You can use this either in scripts to automatically install MySQL or through a terminal connection such as Telnet where you do not have access to the standard Windows user interface. The MSI packages can also be used in combination with Microsoft's Group Policy system (part of Windows Server 2003 and Windows Server 2008) to install MySQL across multiple machines. To install MySQL from one of the MSI packages automatically from the command line (or within a script), you need to use the `msiexec.exe' tool. For example, to perform a quiet installation (which shows no dialog boxes or progress): shell> msiexec /i /quiet mysql-5.1.59.msi The `/i' indicates that you want to perform an installation. The `/quiet' option indicates that you want no interactive elements. To provide a dialog box showing the progress during installation, and the dialog boxes providing information on the installation and registration of MySQL, use `/passive' mode instead of `/quiet': shell> msiexec /i /passive mysql-5.1.59.msi Regardless of the mode of the installation, installing the package in this manner performs a 'Typical' installation, and installs the default components into the standard location. You can also use this method to uninstall MySQL by using the `/uninstall' or `/x' options: shell> msiexec /x /quiet mysql-5.1.59.msi To install MySQL and configure a MySQL instance from the command line, see *Note mysql-config-wizard-cmdline::. For information on using MSI packages to install software automatically using Group Policy, see How to use Group Policy to remotely install software in Windows Server 2003 (http://support.microsoft.com/kb/816102).  File: manual.info, Node: windows-installer-uninstalling, Prev: windows-installer-msi-quiet, Up: windows-using-installer 3.3.3.9 Removing MySQL When Installed from the MSI Package .......................................................... To uninstall a MySQL where you have used the MSI packages, you must use the `Add/Remove Programs' tool within `Control Panel'. To do this: 1. Right-click the `start' menu and choose `Control Panel'. 2. If the Control Panel is set to category mode (you will see `Pick a category' at the top of the `Control Panel' window), double-click `Add or Remove Programs'. If the Control is set to classic mode, double-click the `Add or Remove Programs' icon. 3. Find MySQL in the list of installed software. MySQL Server is installed against major version numbers (MySQL 5.0, MySQL 5.1, etc.). Select the version that you want to remove and click `Remove'. 4. You will be prompted to confirm the removal. Click `Yes' to remove MySQL. When MySQL is removed using this method, only the installed components are removed. Any database information (including the tables and data), import or export files, log files, and binary logs produced during execution are kept in their configured location. If you try to install MySQL again the information will be retained and you will be prompted to enter the password configured with the original installation. If you want to delete MySQL completely: * Delete the associated data directory. On Windows XP and Windows Server 2003, before MySQL 5.1.24, the default data directory would be located within the MySQL installation directory. On MySQL 5.1.24 and later, the default data directory is the configured AppData directory, which is `C:\Documents and Settings\All Users\Application Data\MySQL' by default. * On Windows 7 and Windows Server 2008, the default data directory location is `C:\ProgramData\Mysql'. *Note*: The `C:\ProgramData' directory is hidden by default. You must change your folder options to view the hidden file. Choose `Organize', `Folder and search options', `Show hidden folders'.  File: manual.info, Node: mysql-config-wizard, Next: windows-install-archive, Prev: windows-using-installer, Up: windows-installation 3.3.4 Using the MySQL Server Instance Config Wizard --------------------------------------------------- * Menu: * mysql-config-wizard-starting:: Starting the MySQL Server Instance Config Wizard * mysql-config-wizard-maintenance:: MySQL Server Instance Config Wizard: Choosing a Maintenance Option * mysql-config-wizard-configuration-type:: MySQL Server Instance Config Wizard: Choosing a Configuration Type * mysql-config-wizard-server-type:: MySQL Server Instance Config Wizard: The Server Type Dialog * mysql-config-wizard-database-usage:: MySQL Server Instance Config Wizard: The Database Usage Dialog * mysql-config-wizard-tablespace:: MySQL Server Instance Config Wizard: The InnoDB Tablespace Dialog * mysql-config-wizard-connections:: MySQL Server Instance Config Wizard: The Concurrent Connections Dialog * mysql-config-wizard-networking:: MySQL Server Instance Config Wizard: The Networking and Strict Mode Options Dialog * mysql-config-wizard-character-set:: MySQL Server Instance Config Wizard: The Character Set Dialog * mysql-config-wizard-service:: MySQL Server Instance Config Wizard: The Service Options Dialog * mysql-config-wizard-security:: MySQL Server Instance Config Wizard: The Security Options Dialog * mysql-config-wizard-confirmation:: MySQL Server Instance Config Wizard: The Confirmation Dialog * mysql-config-wizard-cmdline:: MySQL Server Instance Config Wizard: Creating an Instance from the Command Line The MySQL Server Instance Config Wizard helps automate the process of configuring your server. It creates a custom MySQL configuration file (`my.ini' or `my.cnf') by asking you a series of questions and then applying your responses to a template to generate the configuration file that is tuned to your installation. The complete and essential MSI installation packages include the MySQL Server Instance Config Wizard in the MySQL 5.1 server. The MySQL Server Instance Config Wizard is only available for Windows. The workflow sequence for using the MySQL Server Instance Config Wizard is shown in the figure below: FIGURE GOES HERE: MySQL Server Instance Config Wizard Workflow  File: manual.info, Node: mysql-config-wizard-starting, Next: mysql-config-wizard-maintenance, Prev: mysql-config-wizard, Up: mysql-config-wizard 3.3.4.1 Starting the MySQL Server Instance Config Wizard ........................................................ The MySQL Server Instance Config Wizard is normally started as part of the installation process. You should only need to run the MySQL Server Instance Config Wizard again when you need to change the configuration parameters of your server. If you chose not to open a port prior to installing MySQL on Windows Vista or newer, you can choose to use the MySQL Server Instance Config Wizard after installation. However, you must open a port in the Windows Firewall. To do this see the instructions given in *Note mysql-install-wizard-starting::. Rather than opening a port, you also have the option of adding MySQL as a program that bypasses the Windows Firewall. One or the other option is sufficient--you need not do both. Additionally, when running the MySQL Server Config Wizard on Windows Vista or newer, ensure that you are logged in as a user with administrative rights. MySQL Server Instance Config Wizard You can launch the MySQL Config Wizard by clicking the `MySQL Server Instance Config Wizard' entry in the `MySQL' section of the Windows `Start' menu. Alternatively, you can navigate to the `bin' directory of your MySQL installation and launch the `MySQLInstanceConfig.exe' file directly. The MySQL Server Instance Config Wizard places the `my.ini' file in the installation directory for the MySQL server. This helps associate configuration files with particular server instances. To ensure that the MySQL server knows where to look for the `my.ini' file, an argument similar to this is passed to the MySQL server as part of the service installation: --defaults-file="C:\PROGRAM FILES\MYSQL\MYSQL SERVER 5.1\my.ini" Here, C:\PROGRAM FILES\MYSQL\MYSQL SERVER 5.1 is replaced with the installation path to the MySQL Server. The `--defaults-file' option instructs the MySQL server to read the specified file for configuration options when it starts. Apart from making changes to the `my.ini' file by running the MySQL Server Instance Config Wizard again, you can modify it by opening it with a text editor and making any necessary changes. You can also modify the server configuration with the http://www.mysql.com/products/administrator/ utility. For more information about server configuration, see *Note server-options::. MySQL clients and utilities such as the *Note `mysql': mysql. and *Note `mysqldump': mysqldump. command-line clients are not able to locate the `my.ini' file located in the server installation directory. To configure the client and utility applications, create a new `my.ini' file in the Windows installation directory (for example, `C:\WINDOWS'). Under Windows Server 2003, Windows Server 2000, Windows XP, and Windows Vista, MySQL Server Instance Config Wizard will configure MySQL to work as a Windows service. To start and stop MySQL you use the `Services' application that is supplied as part of the Windows Administrator Tools.  File: manual.info, Node: mysql-config-wizard-maintenance, Next: mysql-config-wizard-configuration-type, Prev: mysql-config-wizard-starting, Up: mysql-config-wizard 3.3.4.2 MySQL Server Instance Config Wizard: Choosing a Maintenance Option .......................................................................... If the MySQL Server Instance Config Wizard detects an existing configuration file, you have the option of either reconfiguring your existing server, or removing the server instance by deleting the configuration file and stopping and removing the MySQL service. To reconfigure an existing server, choose the `Re-configure Instance' option and click the `Next' button. Any existing configuration file is not overwritten, but renamed (within the same directory) using a timestamp (Windows) or sequential number (Linux). To remove the existing server instance, choose the `Remove Instance' option and click the `Next' button. If you choose the `Remove Instance' option, you advance to a confirmation window. Click the `Execute' button. The MySQL Server Config Wizard stops and removes the MySQL service, and then deletes the configuration file. The server installation and its `data' folder are not removed. If you choose the `Re-configure Instance' option, you advance to the `Configuration Type' dialog where you can choose the type of installation that you wish to configure.  File: manual.info, Node: mysql-config-wizard-configuration-type, Next: mysql-config-wizard-server-type, Prev: mysql-config-wizard-maintenance, Up: mysql-config-wizard 3.3.4.3 MySQL Server Instance Config Wizard: Choosing a Configuration Type .......................................................................... When you start the MySQL Server Instance Config Wizard for a new MySQL installation, or choose the `Re-configure Instance' option for an existing installation, you advance to the `Configuration Type' dialog. MySQL Server Instance Config Wizard: Configuration Type There are two configuration types available: `Detailed Configuration' and `Standard Configuration'. The `Standard Configuration' option is intended for new users who want to get started with MySQL quickly without having to make many decisions about server configuration. The `Detailed Configuration' option is intended for advanced users who want more fine-grained control over server configuration. If you are new to MySQL and need a server configured as a single-user developer machine, the `Standard Configuration' should suit your needs. Choosing the `Standard Configuration' option causes the MySQL Config Wizard to set all configuration options automatically with the exception of `Service Options' and `Security Options'. The `Standard Configuration' sets options that may be incompatible with systems where there are existing MySQL installations. If you have an existing MySQL installation on your system in addition to the installation you wish to configure, the `Detailed Configuration' option is recommended. To complete the `Standard Configuration', please refer to the sections on `Service Options' and `Security Options' in *Note mysql-config-wizard-service::, and *Note mysql-config-wizard-security::, respectively.  File: manual.info, Node: mysql-config-wizard-server-type, Next: mysql-config-wizard-database-usage, Prev: mysql-config-wizard-configuration-type, Up: mysql-config-wizard 3.3.4.4 MySQL Server Instance Config Wizard: The Server Type Dialog ................................................................... There are three different server types available to choose from. The server type that you choose affects the decisions that the MySQL Server Instance Config Wizard makes with regard to memory, disk, and processor usage. MySQL Server Instance Config Wizard: Server Type * `Developer Machine': Choose this option for a typical desktop workstation where MySQL is intended only for personal use. It is assumed that many other desktop applications are running. The MySQL server is configured to use minimal system resources. * `Server Machine': Choose this option for a server machine where the MySQL server is running alongside other server applications such as FTP, email, and Web servers. The MySQL server is configured to use a moderate portion of the system resources. * `Dedicated MySQL Server Machine': Choose this option for a server machine that is intended to run only the MySQL server. It is assumed that no other applications are running. The MySQL server is configured to use all available system resources. *Note*: By selecting one of the preconfigured configurations, the values and settings of various options in your `my.cnf' or `my.ini' will be altered accordingly. The default values and options as described in the reference manual may therefore be different to the options and values that were created during the execution of the Config Wizard.  File: manual.info, Node: mysql-config-wizard-database-usage, Next: mysql-config-wizard-tablespace, Prev: mysql-config-wizard-server-type, Up: mysql-config-wizard 3.3.4.5 MySQL Server Instance Config Wizard: The Database Usage Dialog ...................................................................... The `Database Usage' dialog enables you to indicate the storage engines that you expect to use when creating MySQL tables. The option you choose determines whether the `InnoDB' storage engine is available and what percentage of the server resources are available to `InnoDB'. MySQL Server Instance Config Wizard: Usage Dialog * `Multifunctional Database': This option enables both the `InnoDB' and `MyISAM' storage engines and divides resources evenly between the two. This option is recommended for users who use both storage engines on a regular basis. * `Transactional Database Only': This option enables both the `InnoDB' and `MyISAM' storage engines, but dedicates most server resources to the `InnoDB' storage engine. This option is recommended for users who use `InnoDB' almost exclusively and make only minimal use of `MyISAM'. * `Non-Transactional Database Only': This option disables the `InnoDB' storage engine completely and dedicates all server resources to the `MyISAM' storage engine. This option is recommended for users who do not use `InnoDB'. The Config Wizard uses a template to generate the server configuration file. The `Database Usage' dialog sets one of the following option strings: Multifunctional Database: MIXED Transactional Database Only: INNODB Non-Transactional Database Only: MYISAM When these options are processed through the default template (my-template.ini) the result is: Multifunctional Database: default-storage-engine=InnoDB _myisam_pct=50 Transactional Database Only: default-storage-engine=InnoDB _myisam_pct=5 Non-Transactional Database Only: default-storage-engine=MyISAM _myisam_pct=100 skip-innodb The `_myisam_pct' value is used to calculate the percentage of resources dedicated to `MyISAM'. The remaining resources are allocated to `InnoDB'.  File: manual.info, Node: mysql-config-wizard-tablespace, Next: mysql-config-wizard-connections, Prev: mysql-config-wizard-database-usage, Up: mysql-config-wizard 3.3.4.6 MySQL Server Instance Config Wizard: The InnoDB Tablespace Dialog ......................................................................... Some users may want to locate the `InnoDB' tablespace files in a different location than the MySQL server data directory. Placing the tablespace files in a separate location can be desirable if your system has a higher capacity or higher performance storage device available, such as a RAID storage system. MySQL Server Instance Config Wizard: InnoDB Data Tablespace To change the default location for the `InnoDB' tablespace files, choose a new drive from the drop-down list of drive letters and choose a new path from the drop-down list of paths. To create a custom path, click the `...' button. If you are modifying the configuration of an existing server, you must click the `Modify' button before you change the path. In this situation you must move the existing tablespace files to the new location manually before starting the server.  File: manual.info, Node: mysql-config-wizard-connections, Next: mysql-config-wizard-networking, Prev: mysql-config-wizard-tablespace, Up: mysql-config-wizard 3.3.4.7 MySQL Server Instance Config Wizard: The Concurrent Connections Dialog .............................................................................. To prevent the server from running out of resources, it is important to limit the number of concurrent connections to the MySQL server that can be established. The `Concurrent Connections' dialog enables you to choose the expected usage of your server, and sets the limit for concurrent connections accordingly. It is also possible to set the concurrent connection limit manually. MySQL Server Instance Config Wizard: Connections * `Decision Support (DSS)/OLAP': Choose this option if your server does not require a large number of concurrent connections. The maximum number of connections is set at 100, with an average of 20 concurrent connections assumed. * `Online Transaction Processing (OLTP)': Choose this option if your server requires a large number of concurrent connections. The maximum number of connections is set at 500. * `Manual Setting': Choose this option to set the maximum number of concurrent connections to the server manually. Choose the number of concurrent connections from the drop-down box provided, or enter the maximum number of connections into the drop-down box if the number you desire is not listed.  File: manual.info, Node: mysql-config-wizard-networking, Next: mysql-config-wizard-character-set, Prev: mysql-config-wizard-connections, Up: mysql-config-wizard 3.3.4.8 MySQL Server Instance Config Wizard: The Networking and Strict Mode Options Dialog .......................................................................................... Use the `Networking Options' dialog to enable or disable TCP/IP networking and to configure the port number that is used to connect to the MySQL server. MySQL Server Instance Config Wizard: Network Configuration TCP/IP networking is enabled by default. To disable TCP/IP networking, uncheck the box next to the `Enable TCP/IP Networking' option. Port 3306 is used by default. To change the port used to access MySQL, choose a new port number from the drop-down box or type a new port number directly into the drop-down box. If the port number you choose is in use, you are prompted to confirm your choice of port number. Set the `Server SQL Mode' to either enable or disable strict mode. Enabling strict mode (default) makes MySQL behave more like other database management systems. _If you run applications that rely on MySQL's old `forgiving' behavior, make sure to either adapt those applications or to disable strict mode._ For more information about strict mode, see *Note server-sql-mode::.  File: manual.info, Node: mysql-config-wizard-character-set, Next: mysql-config-wizard-service, Prev: mysql-config-wizard-networking, Up: mysql-config-wizard 3.3.4.9 MySQL Server Instance Config Wizard: The Character Set Dialog ..................................................................... The MySQL server supports multiple character sets and it is possible to set a default server character set that is applied to all tables, columns, and databases unless overridden. Use the `Character Set' dialog to change the default character set of the MySQL server. MySQL Server Instance Config Wizard: Character Set * `Standard Character Set': Choose this option if you want to use `latin1' as the default server character set. `latin1' is used for English and many Western European languages. * `Best Support For Multilingualism': Choose this option if you want to use `utf8' as the default server character set. This is a Unicode character set that can store characters from many different languages. * `Manual Selected Default Character Set / Collation': Choose this option if you want to pick the server's default character set manually. Choose the desired character set from the provided drop-down list.  File: manual.info, Node: mysql-config-wizard-service, Next: mysql-config-wizard-security, Prev: mysql-config-wizard-character-set, Up: mysql-config-wizard 3.3.4.10 MySQL Server Instance Config Wizard: The Service Options Dialog ........................................................................ On Windows platforms, the MySQL server can be installed as a Windows service. When installed this way, the MySQL server can be started automatically during system startup, and even restarted automatically by Windows in the event of a service failure. The MySQL Server Instance Config Wizard installs the MySQL server as a service by default, using the service name `MySQL'. If you do not wish to install the service, uncheck the box next to the `Install As Windows Service' option. You can change the service name by picking a new service name from the drop-down box provided or by entering a new service name into the drop-down box. *Note*: Service names can include any legal character except forward (`/') or backward (`\') slashes, and must be less than 256 characters long. *Warning*: If you are installing multiple versions of MySQL onto the same machine, you _must_ choose a different service name for each version that you install. If you do not choose a different service for each installed version then the service manager information will be inconsistent and this will cause problems when you try to uninstall a previous version. If you have already installed multiple versions using the same service name, you must manually edit the contents of the `HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services' parameters within the Windows registry to update the association of the service name with the correct server version. Typically, when installing multiple versions you create a service name based on the version information. For example, you might install MySQL 5.x as `mysql5', or specific versions such as MySQL 5.1.30 as `mysql50130'. To install the MySQL server as a service but not have it started automatically at startup, uncheck the box next to the `Launch the MySQL Server Automatically' option.  File: manual.info, Node: mysql-config-wizard-security, Next: mysql-config-wizard-confirmation, Prev: mysql-config-wizard-service, Up: mysql-config-wizard 3.3.4.11 MySQL Server Instance Config Wizard: The Security Options Dialog ......................................................................... The content of the security options portion of the MySQL Server Instance Configuration Wizard will depend on whether this is a new installation, or modifying an existing installation. * *Setting the root password for a new installation* _It is strongly recommended that you set a `root' password for your MySQL server_, and the MySQL Server Instance Config Wizard requires by default that you do so. If you do not wish to set a `root' password, uncheck the box next to the `Modify Security Settings' option. *Note*: If you have previously installed MySQL, but not deleted the data directory associated with the previous installation, you may be prompted to provide the current root password. The password will be the one configured with your old data directory. If you do not want to use this data, or do not know the root password, you should cancel the installation, delete the previous installation data, and then restart the installation process. For more information on deleting MySQL data on Microsoft Windows, see *Note windows-installer-uninstalling::. MySQL Server Instance Config Wizard: Security * To set the `root' password, enter the desired password into both the `New root password' and `Confirm' boxes. *Setting the root password for an existing installation* If you are modifying the configuration of an existing configuration, or you are installing an upgrade and the MySQL Server Instance Configuration Wizard has detected an existing MySQL system, then you must enter the existing password for `root' before changing the configuration information. MySQL Server Instance Config Wizard: Security (Existing Installation) If you want to change the current `root' password, enter the desired new password into both the `New root password' and `Confirm' boxes. To permit `root' logins from across the network, check the box next to the `Enable root access from remote machines' option. This decreases the security of your `root' account. To create an anonymous user account, check the box next to the `Create An Anonymous Account' option. Creating an anonymous account can decrease server security and cause login and permission difficulties. For this reason, it is not recommended.  File: manual.info, Node: mysql-config-wizard-confirmation, Next: mysql-config-wizard-cmdline, Prev: mysql-config-wizard-security, Up: mysql-config-wizard 3.3.4.12 MySQL Server Instance Config Wizard: The Confirmation Dialog ..................................................................... The final dialog in the MySQL Server Instance Config Wizard is the `Confirmation Dialog'. To start the configuration process, click the `Execute' button. To return to a previous dialog, click the `Back' button. To exit the MySQL Server Instance Config Wizard without configuring the server, click the `Cancel' button. MySQL Server Instance Config Wizard: Confirmation After you click the `Execute' button, the MySQL Server Instance Config Wizard performs a series of tasks and displays the progress onscreen as the tasks are performed. The MySQL Server Instance Config Wizard first determines configuration file options based on your choices using a template prepared by MySQL developers and engineers. This template is named `my-template.ini' and is located in your server installation directory. The MySQL Config Wizard then writes these options to the corresponding configuration file. If you chose to create a service for the MySQL server, the MySQL Server Instance Config Wizard creates and starts the service. If you are reconfiguring an existing service, the MySQL Server Instance Config Wizard restarts the service to apply your configuration changes. If you chose to set a `root' password, the MySQL Config Wizard connects to the server, sets your new `root' password, and applies any other security settings you may have selected. After the MySQL Server Instance Config Wizard has completed its tasks, it displays a summary. Click the `Finish' button to exit the MySQL Server Config Wizard.  File: manual.info, Node: mysql-config-wizard-cmdline, Prev: mysql-config-wizard-confirmation, Up: mysql-config-wizard 3.3.4.13 MySQL Server Instance Config Wizard: Creating an Instance from the Command Line ........................................................................................ In addition to using the GUI interface to the MySQL Server Instance Config Wizard, you can also create instances automatically from the command line. To use the MySQL Server Instance Config Wizard on the command line, you need to use the `MySQLInstanceConfig.exe' command that is installed with MySQL in the `bin' directory within the installation directory. `MySQLInstanceConfig.exe' takes a number of command-line arguments the set the properties that would normally be selected through the GUI interface, and then creates a new configuration file (`my.ini') by combining these selections with a template configuration file to produce the working configuration file. The main command line options are provided in the table below. Some of the options are required, while some options are optional. *MySQL Server Instance Config Wizard Command Line Options* Option Description Required Parameters `-nPRODUCTNAME'The name of the instance when installed `-pPATH' Path of the base directory for installation. This is equivalent to the directory when using the `basedir' configuration parameter `-vVERSION' The version tag to use for this installation Action to Perform `-i' Install an instance `-r' Remove an instance `-s' Stop an existing instance `-q' Perform the operation quietly `-lFILENAME' Sae the installation progress in a logfile Config File to Use `-tFILENAME' Path to the template config file that will be used to generate the installed configuration file `-cFILENAME' Path to a config file to be generated The `-t' and `-c' options work together to set the configuration parameters for a new instance. The `-t' option specifies the template configuration file to use as the basic configuration, which are then merged with the configuration parameters generated by the MySQL Server Instance Config Wizard into the configuration file specified by the `-c' option. A sample template file, `my-template.ini' is provided in the toplevel MySQL installation directory. The file contains elements are replaced automatically by the MySQL Server Instance Config Wizard during configuration. If you specify a configuration file that already exists, the existing configuration file will be saved in the file with the original, with the date and time added. For example, the `mysql.ini' will be copied to `mysql 2009-10-27 1646.ini.bak'. The parameters that you can specify on the command line are listed in the table below. *MySQL Server Instance Config Wizard Parameters* Parameter Description `ServiceName=$'Specify the name of the service to be created `AddBinToPath={yesSpecifies whether to add the binary | no}' directory of MySQL to the standard `PATH' environment variable `ServerType={DEVELOPMENTSpecify the server type. For more | SERVER | information, see *Note DEDICATED}' mysql-config-wizard-server-type:: `DatabaseType={MIXEDSpecify the default database type. For | INNODB | more information, see *Note MYISAM}' mysql-config-wizard-database-usage:: `ConnectionUsage={DSSSpecify the type of connection support, | OLTP}' this automates the setting for the number of concurrent connections (see the `ConnectionCount' parameter). For more information, see *Note mysql-config-wizard-connections:: `ConnectionCount=#'Specify the number of concurrent connections to support. For more information, see *Note mysql-config-wizard-server-type:: `SkipNetworking={yesSpecify whether network support should be | no}' supported. Specifying `yes' disables network access altogether `Port=#' Specify the network port number to use for network connections. For more information, see *Note mysql-config-wizard-networking:: `StrictMode={yesSpecify whether to use the `strict' SQL | no}' mode. For more information, see *Note mysql-config-wizard-networking:: `Charset=$' Specify the default character set. For more information, see *Note mysql-config-wizard-character-set:: `RootPassword=$'Specify the root password `RootCurrentPassword=$'Specify the current root password then stopping or reconfiguring an existing service *Note*: When specifying options on the command line, you can enclose the entire command-line option and the value you are specifying using double quotation marks. This enables you to use spaces in the options. For example, `"-cC:\mysql.ini"'. The following command installs a MySQL Server 5.1 instance from the directory `C:\Program Files\MySQL\MySQL Server 5.1' using the service name `MySQL51' and setting the root password to 1234. shell> MySQLInstanceConfig.exe -i -q "-lC:\mysql_install_log.txt" » "-nMySQL Server 5.1" "-pC:\Program Files\MySQL\MySQL Server 5.1" -v5.1.59 » "-tmy-template.ini" "-cC:\mytest.ini" ServerType=DEVELOPMENT DatabaseType=MIXED » ConnectionUsage=DSS Port=3311 ServiceName=MySQL51 RootPassword=1234 In the above example, a log file will be generated in `mysql_install_log.txt' containing the information about the instance creation process. The log file generated by the above example is shown below: Welcome to the MySQL Server Instance Configuration Wizard 1.0.16.0 Date: 2009-10-27 17:07:21 Installing service ... Product Name: MySQL Server 5.1 Version: 5.1.59 Installation Path: C:\Program Files\MySQL\MySQL Server 5.1\ Creating configuration file C:\mytest.ini using template my-template.ini. Options: DEVELOPMENT MIXED DSS STRICTMODE Variables: port: 3311 default-character-set: latin1 basedir: "C:/Program Files/MySQL/MySQL Server 5.1/" datadir: "C:/Program Files/MySQL/MySQL Server 5.1/Data/" Creating Windows service entry. Service name: "MySQL51" Parameters: "C:\Program Files\MySQL\MySQL Server 5.1\bin\mysqld" --defaults-file="C:\mytest.ini" MySQL51. Windows service MySQL51 installed. When using the command line, the return values in the following table indicate an error performing the specified option. *Return Value from MySQL Server Instance Config Wizard* Value Description 2 Configuration template file cannot be found 3 The Windows service entry cannot be created 4 Could not connect to the Service Control Manager 5 The MySQL service cannot be started 6 The MySQL service cannot be stopped 7 The security settings cannot be applied 8 The configuration file cannot be written 9 The Windows service entry cannot be removed You can perform an installation of MySQL automatically using the MSI package. For more information, see *Note windows-installer-msi-quiet::.  File: manual.info, Node: windows-install-archive, Next: windows-troubleshooting, Prev: mysql-config-wizard, Up: windows-installation 3.3.5 Installing MySQL on Microsoft Windows Using a `noinstall' Zip Archive --------------------------------------------------------------------------- * Menu: * windows-extract-archive:: Extracting the Install Archive * windows-create-option-file:: Creating an Option File * windows-select-server:: Selecting a MySQL Server Type * windows-server-first-start:: Starting MySQL Server on Microsoft Windows for the First Time * windows-start-command-line:: Starting MySQL Server from the Windows Command Line * mysql-installation-windows-path:: Customizing the PATH for MySQL Tools * windows-start-service:: Starting MySQL Server as a Microsoft Windows Service * windows-testing:: Testing The MySQL Server Installation on Microsoft Windows Users who are installing from the `noinstall' package can use the instructions in this section to manually install MySQL. The process for installing MySQL from a Zip archive is as follows: 1. Extract the archive to the desired install directory 2. Create an option file 3. Choose a MySQL server type 4. Start the MySQL server 5. Secure the default user accounts This process is described in the sections that follow.  File: manual.info, Node: windows-extract-archive, Next: windows-create-option-file, Prev: windows-install-archive, Up: windows-install-archive 3.3.5.1 Extracting the Install Archive ...................................... To install MySQL manually, do the following: 1. If you are upgrading from a previous version please refer to *Note windows-upgrading::, before beginning the upgrade process. 2. Make sure that you are logged in as a user with administrator privileges. 3. Choose an installation location. Traditionally, the MySQL server is installed in `C:\mysql'. The MySQL Installation Wizard installs MySQL under `C:\Program Files\MySQL'. If you do not install MySQL at `C:\mysql', you must specify the path to the install directory during startup or in an option file. See *Note windows-create-option-file::. 4. Extract the install archive to the chosen installation location using your preferred Zip archive tool. Some tools may extract the archive to a folder within your chosen installation location. If this occurs, you can move the contents of the subfolder into the chosen installation location.  File: manual.info, Node: windows-create-option-file, Next: windows-select-server, Prev: windows-extract-archive, Up: windows-install-archive 3.3.5.2 Creating an Option File ............................... If you need to specify startup options when you run the server, you can indicate them on the command line or place them in an option file. For options that are used every time the server starts, you may find it most convenient to use an option file to specify your MySQL configuration. This is particularly true under the following circumstances: * The installation or data directory locations are different from the default locations (`C:\Program Files\MySQL\MySQL Server 5.1' and `C:\Program Files\MySQL\MySQL Server 5.1\data'). * You need to tune the server settings, such as memory, cache, or InnoDB configuration information. When the MySQL server starts on Windows, it looks for option files in several locations, such as the Windows directory, `C:\', and the MySQL installation directory (for the full list of locations, see *Note option-files::). The Windows directory typically is named something like `C:\WINDOWS'. You can determine its exact location from the value of the `WINDIR' environment variable using the following command: C:\> echo %WINDIR% MySQL looks for options in each location first in the `my.ini' file, and then in the `my.cnf' file. However, to avoid confusion, it is best if you use only one file. If your PC uses a boot loader where `C:' is not the boot drive, your only option is to use the `my.ini' file. Whichever option file you use, it must be a plain text file. You can also make use of the example option files included with your MySQL distribution; see *Note option-files-preconfigured::. An option file can be created and modified with any text editor, such as Notepad. For example, if MySQL is installed in `E:\mysql' and the data directory is in `E:\mydata\data', you can create an option file containing a `[mysqld]' section to specify values for the `basedir' and `datadir' options: [mysqld] # set basedir to your installation path basedir=E:/mysql # set datadir to the location of your data directory datadir=E:/mydata/data Note that Windows path names are specified in option files using (forward) slashes rather than backslashes. If you do use backslashes, double them: [mysqld] # set basedir to your installation path basedir=E:\\mysql # set datadir to the location of your data directory datadir=E:\\mydata\\data The rules for use of backslash in option file values are given in *Note option-files::. In MySQL 5.1.23 and earlier, the MySQL installer places the data directory directly under the directory where you install MySQL. On MySQL 5.1.24 and later, the data directory is located within the `AppData' directory for the user running MySQL. If you would like to use a data directory in a different location, you should copy the entire contents of the `data' directory to the new location. For example, if you want to use `E:\mydata' as the data directory instead, you must do two things: 1. Move the entire `data' directory and all of its contents from the default location (for example `C:\Program Files\MySQL\MySQL Server 5.1\data') to `E:\mydata'. 2. Use a `--datadir' option to specify the new data directory location each time you start the server.  File: manual.info, Node: windows-select-server, Next: windows-server-first-start, Prev: windows-create-option-file, Up: windows-install-archive 3.3.5.3 Selecting a MySQL Server Type ..................................... The following table shows the available servers for Windows in MySQL 5.1.20 and earlier. *`mysqld' binary types for Microsoft Windows up to MySQL 5.1.20* Binary Description *Note Optimized binary with named-pipe support `mysqld-nt': mysqld. *Note Optimized binary without named-pipe support `mysqld': mysqld. *Note Like *Note `mysqld-nt': mysqld, but compiled with full `mysqld-debug':debugging and automatic memory allocation checking mysqld. The following table shows the available servers for Windows in MySQL 5.1.21 and later. *`mysqld' binary types for Microsoft Windows MySQL 5.1.21 and later* Binary Description *Note Optimized binary with named-pipe support `mysqld': mysqld. *Note Like *Note `mysqld': mysqld, but compiled with full `mysqld-debug':debugging and automatic memory allocation checking mysqld. All of the preceding binaries are optimized for modern Intel processors, but should work on any Intel i386-class or higher processor. Each of the servers in a distribution support the same set of storage engines. The *Note `SHOW ENGINES': show-engines. statement displays which engines a given server supports. All Windows MySQL 5.1 servers have support for symbolic linking of database directories. MySQL supports TCP/IP on all Windows platforms. MySQL servers on Windows support named pipes as indicated in the following list. However, the default is to use TCP/IP regardless of platform. (Named pipes are slower than TCP/IP in many Windows configurations.) Use of named pipes is subject to these conditions: * Named pipes are enabled only if you start the server with the `--enable-named-pipe' option. It is necessary to use this option explicitly because some users have experienced problems with shutting down the MySQL server when named pipes were used. * For MySQL 5.1.20 and earlier, named-pipe connections are permitted only by the *Note `mysqld-nt': mysqld. and *Note `mysqld-debug': mysqld. servers. For MySQL 5.1.21 and later, the *Note `mysqld': mysqld. and *Note `mysqld-debug': mysqld. servers both contain support for named-pipe connections. *Note*: Most of the examples in this manual use *Note `mysqld': mysqld. as the server name. If you choose to use a different server, such as *Note `mysqld-nt': mysqld. or *Note `mysqld-debug': mysqld, make the appropriate substitutions in the commands that are shown in the examples.  File: manual.info, Node: windows-server-first-start, Next: windows-start-command-line, Prev: windows-select-server, Up: windows-install-archive 3.3.5.4 Starting MySQL Server on Microsoft Windows for the First Time ..................................................................... This section gives a general overview of starting the MySQL server. The following sections provide more specific information for starting the MySQL server from the command line or as a Windows service. The information here applies primarily if you installed MySQL using the `Noinstall' version, or if you wish to configure and test MySQL manually rather than with the GUI tools. The examples in these sections assume that MySQL is installed under the default location of `C:\Program Files\MySQL\MySQL Server 5.1'. Adjust the path names shown in the examples if you have MySQL installed in a different location. Clients have two options. They can use TCP/IP, or they can use a named pipe if the server supports named-pipe connections. MySQL for Windows also supports shared-memory connections if the server is started with the `--shared-memory' option. Clients can connect through shared memory by using the `--protocol=MEMORY' option. For information about which server binary to run, see *Note windows-select-server::. Testing is best done from a command prompt in a console window (or `DOS window'). In this way you can have the server display status messages in the window where they are easy to see. If something is wrong with your configuration, these messages make it easier for you to identify and fix any problems. To start the server, enter this command: C:\> "C:\Program Files\MySQL\MySQL Server 5.1\bin\mysqld" --console For a server that includes `InnoDB' support, you should see the messages similar to those following as it starts (the path names and sizes may differ): InnoDB: The first specified datafile c:\ibdata\ibdata1 did not exist: InnoDB: a new database to be created! InnoDB: Setting file c:\ibdata\ibdata1 size to 209715200 InnoDB: Database physically writes the file full: wait... InnoDB: Log file c:\iblogs\ib_logfile0 did not exist: new to be created InnoDB: Setting log file c:\iblogs\ib_logfile0 size to 31457280 InnoDB: Log file c:\iblogs\ib_logfile1 did not exist: new to be created InnoDB: Setting log file c:\iblogs\ib_logfile1 size to 31457280 InnoDB: Log file c:\iblogs\ib_logfile2 did not exist: new to be created InnoDB: Setting log file c:\iblogs\ib_logfile2 size to 31457280 InnoDB: Doublewrite buffer not found: creating new InnoDB: Doublewrite buffer created InnoDB: creating foreign key constraint system tables InnoDB: foreign key constraint system tables created 011024 10:58:25 InnoDB: Started When the server finishes its startup sequence, you should see something like this, which indicates that the server is ready to service client connections: mysqld: ready for connections Version: '5.1.59' socket: '' port: 3306 The server continues to write to the console any further diagnostic output it produces. You can open a new console window in which to run client programs. If you omit the `--console' option, the server writes diagnostic output to the error log in the data directory (`C:\Program Files\MySQL\MySQL Server 5.1\data' by default). The error log is the file with the `.err' extension. *Note*: The accounts that are listed in the MySQL grant tables initially have no passwords. After starting the server, you should set up passwords for them using the instructions in *Note postinstallation::.  File: manual.info, Node: windows-start-command-line, Next: mysql-installation-windows-path, Prev: windows-server-first-start, Up: windows-install-archive 3.3.5.5 Starting MySQL Server from the Windows Command Line ........................................................... The MySQL server can be started manually from the command line. This can be done on any version of Windows. To start the *Note `mysqld': mysqld. server from the command line, you should start a console window (or `DOS window') and enter this command: C:\> "C:\Program Files\MySQL\MySQL Server 5.1\bin\mysqld" The path to *Note `mysqld': mysqld. may vary depending on the install location of MySQL on your system. You can stop the MySQL server by executing this command: C:\> "C:\Program Files\MySQL\MySQL Server 5.1\bin\mysqladmin" -u root shutdown *Note*: If the MySQL `root' user account has a password, you need to invoke *Note `mysqladmin': mysqladmin. with the `-p' option and supply the password when prompted. This command invokes the MySQL administrative utility *Note `mysqladmin': mysqladmin. to connect to the server and tell it to shut down. The command connects as the MySQL `root' user, which is the default administrative account in the MySQL grant system. Note that users in the MySQL grant system are wholly independent from any login users under Windows. If *Note `mysqld': mysqld. doesn't start, check the error log to see whether the server wrote any messages there to indicate the cause of the problem. The error log is located in the `C:\Program Files\MySQL\MySQL Server 5.1\data' directory. It is the file with a suffix of `.err'. You can also try to start the server as *Note `mysqld --console': mysqld.; in this case, you may get some useful information on the screen that may help solve the problem. The last option is to start *Note `mysqld': mysqld. with the `--standalone' and `--debug' options. In this case, *Note `mysqld': mysqld. writes a log file `C:\mysqld.trace' that should contain the reason why *Note `mysqld': mysqld. doesn't start. See MySQL Internals: Porting (http://forge.mysql.com/wiki/MySQL_Internals_Porting). Use *Note `mysqld --verbose --help': mysqld. to display all the options that *Note `mysqld': mysqld. supports.  File: manual.info, Node: mysql-installation-windows-path, Next: windows-start-service, Prev: windows-start-command-line, Up: windows-install-archive 3.3.5.6 Customizing the PATH for MySQL Tools ............................................ To make it easier to invoke MySQL programs, you can add the path name of the MySQL `bin' directory to your Windows system `PATH' environment variable: * On the Windows desktop, right-click the `My Computer' icon, and select `Properties'. * Next select the `Advanced' tab from the `System Properties' menu that appears, and click the `Environment Variables' button. * Under `System Variables', select `Path', and then click the `Edit' button. The `Edit System Variable' dialogue should appear. * Place your cursor at the end of the text appearing in the space marked `Variable Value'. (Use the `End' key to ensure that your cursor is positioned at the very end of the text in this space.) Then enter the complete path name of your MySQL `bin' directory (for example, `C:\Program Files\MySQL\MySQL Server 5.1\bin') *Note*: There must be a semicolon separating this path from any values present in this field. Dismiss this dialogue, and each dialogue in turn, by clicking `OK' until all of the dialogues that were opened have been dismissed. You should now be able to invoke any MySQL executable program by typing its name at the DOS prompt from any directory on the system, without having to supply the path. This includes the servers, the *Note `mysql': mysql. client, and all MySQL command-line utilities such as *Note `mysqladmin': mysqladmin. and *Note `mysqldump': mysqldump. You should not add the MySQL `bin' directory to your Windows `PATH' if you are running multiple MySQL servers on the same machine. *Warning*: You must exercise great care when editing your system `PATH' by hand; accidental deletion or modification of any portion of the existing `PATH' value can leave you with a malfunctioning or even unusable system.  File: manual.info, Node: windows-start-service, Next: windows-testing, Prev: mysql-installation-windows-path, Up: windows-install-archive 3.3.5.7 Starting MySQL Server as a Microsoft Windows Service ............................................................ On Windows, the recommended way to run MySQL is to install it as a Windows service, whereby MySQL starts and stops automatically when Windows starts and stops, and can be managed using the service manager framework. A MySQL server installed as a service can also be controlled from the command line using `NET' commands, or with the graphical `Services' utility. Generally, to install MySQL as a Windows service you should be logged in using an account that has administrator rights. The `Services' utility (the Windows `Service Control Manager') can be found in the Windows Control Panel (under `Administrative Tools' on Windows 2000, XP, Vista, and Server 2003). To avoid conflicts, it is advisable to close the `Services' utility while performing server installation or removal operations from the command line. Before installing MySQL as a Windows service, you should first stop the current server if it is running by using the following command: C:\> "C:\Program Files\MySQL\MySQL Server 5.1\bin\mysqladmin" -u root shutdown *Note*: If the MySQL `root' user account has a password, you need to invoke *Note `mysqladmin': mysqladmin. with the `-p' option and supply the password when prompted. This command invokes the MySQL administrative utility *Note `mysqladmin': mysqladmin. to connect to the server and tell it to shut down. The command connects as the MySQL `root' user, which is the default administrative account in the MySQL grant system. Note that users in the MySQL grant system are wholly independent from any login users under Windows. Install the server as a service using this command: C:\> "C:\Program Files\MySQL\MySQL Server 5.1\bin\mysqld" --install *Note*: The service-installation command does not start the server. The following additional arguments can be used when installing the service: * You can specify a service name immediately following the `--install' option. The default service name is `MySQL'. * If a service name is given, it can be followed by a single option. By convention, this should be `--defaults-file=FILE_NAME' to specify the name of an option file from which the server should read options when it starts. The use of a single option other than `--defaults-file' is possible but discouraged. `--defaults-file' is more flexible because it enables you to specify multiple startup options for the server by placing them in the named option file. * You can also specify a `--local-service' option following the service name. This causes the server to run using the `LocalService' Windows account that has limited system privileges. This account is available only for Windows XP or newer. If both `--defaults-file' and `--local-service' are given following the service name, they can be in any order. For a MySQL server that is installed as a Windows service, the following rules determine the service name and option files that the server uses: * If the service-installation command specifies no service name or the default service name (`MySQL') following the `--install' option, the server uses the a service name of `MySQL' and reads options from the `[mysqld]' group in the standard option files. * If the service-installation command specifies a service name other than `MySQL' following the `--install' option, the server uses that service name. It reads options from the `[mysqld]' group and the group that has the same name as the service in the standard option files. This enables you to use the `[mysqld]' group for options that should be used by all MySQL services, and an option group with the service name for use by the server installed with that service name. * If the service-installation command specifies a `--defaults-file' option after the service name, the server reads options only from the `[mysqld]' group of the named file and ignores the standard option files. As a more complex example, consider the following command: C:\> "C:\Program Files\MySQL\MySQL Server 5.1\bin\mysqld" --install MySQL --defaults-file=C:\my-opts.cnf Here, the default service name (`MySQL') is given after the `--install' option. If no `--defaults-file' option had been given, this command would have the effect of causing the server to read the `[mysqld]' group from the standard option files. However, because the `--defaults-file' option is present, the server reads options from the `[mysqld]' option group, and only from the named file. You can also specify options as Start parameters in the Windows `Services' utility before you start the MySQL service. Once a MySQL server has been installed as a service, Windows starts the service automatically whenever Windows starts. The service also can be started immediately from the `Services' utility, or by using a `NET START MySQL' command. The `NET' command is not case sensitive. When run as a service, *Note `mysqld': mysqld. has no access to a console window, so no messages can be seen there. If *Note `mysqld': mysqld. does not start, check the error log to see whether the server wrote any messages there to indicate the cause of the problem. The error log is located in the MySQL data directory (for example, `C:\Program Files\MySQL\MySQL Server 5.1\data'). It is the file with a suffix of `.err'. When a MySQL server has been installed as a service, and the service is running, Windows stops the service automatically when Windows shuts down. The server also can be stopped manually by using the `Services' utility, the `NET STOP MySQL' command, or the *Note `mysqladmin shutdown': mysqladmin. command. You also have the choice of installing the server as a manual service if you do not wish for the service to be started automatically during the boot process. To do this, use the `--install-manual' option rather than the `--install' option: C:\> "C:\Program Files\MySQL\MySQL Server 5.1\bin\mysqld" --install-manual To remove a server that is installed as a service, first stop it if it is running by executing `NET STOP MySQL'. Then use the `--remove' option to remove it: C:\> "C:\Program Files\MySQL\MySQL Server 5.1\bin\mysqld" --remove If *Note `mysqld': mysqld. is not running as a service, you can start it from the command line. For instructions, see *Note windows-start-command-line::. Please see *Note windows-troubleshooting::, if you encounter difficulties during installation.  File: manual.info, Node: windows-testing, Prev: windows-start-service, Up: windows-install-archive 3.3.5.8 Testing The MySQL Server Installation on Microsoft Windows .................................................................. You can test whether the MySQL server is working by executing any of the following commands: C:\> "C:\Program Files\MySQL\MySQL Server 5.1\bin\mysqlshow" C:\> "C:\Program Files\MySQL\MySQL Server 5.1\bin\mysqlshow" -u root mysql C:\> "C:\Program Files\MySQL\MySQL Server 5.1\bin\mysqladmin" version status proc C:\> "C:\Program Files\MySQL\MySQL Server 5.1\bin\mysql" test *Note*: By default, *Note `mysqlshow': mysqlshow. will try to connect using the `ODBC' user. This user is not created by default. You should specify a valid user, or `root' with the right password to check the operation of the server. If *Note `mysqld': mysqld. is slow to respond to TCP/IP connections from client programs, there is probably a problem with your DNS. In this case, start *Note `mysqld': mysqld. with the `--skip-name-resolve' option and use only `localhost' and IP addresses in the `Host' column of the MySQL grant tables. You can force a MySQL client to use a named-pipe connection rather than TCP/IP by specifying the `--pipe' or `--protocol=PIPE' option, or by specifying `.' (period) as the host name. Use the `--socket' option to specify the name of the pipe if you do not want to use the default pipe name. Note that if you have set a password for the `root' account, deleted the anonymous account, or created a new user account, then you must use the appropriate `-u' and `-p' options with the commands shown above to connect with the MySQL Server. See *Note connecting::. For more information about *Note `mysqlshow': mysqlshow, see *Note mysqlshow::.  File: manual.info, Node: windows-troubleshooting, Next: windows-upgrading, Prev: windows-install-archive, Up: windows-installation 3.3.6 Troubleshooting a Microsoft Windows MySQL Server Installation ------------------------------------------------------------------- When installing and running MySQL for the first time, you may encounter certain errors that prevent the MySQL server from starting. The purpose of this section is to help you diagnose and correct some of these errors. Your first resource when troubleshooting server issues is the error log. The MySQL server uses the error log to record information relevant to the error that prevents the server from starting. The error log is located in the data directory specified in your `my.ini' file. The default data directory location is `C:\Program Files\MySQL\MySQL Server 5.1\data', or `C:\ProgramData\Mysql' on Windows 7 and Windows Server 2008. The `C:\ProgramData' diectory is hidden by default. You need to change your folder options to see the directory and contents. For more information on the error log and understanding the content, see *Note error-log::. Another source of information regarding possible errors is the console messages displayed when the MySQL service is starting. Use the `NET START MySQL' command from the command line after installing *Note `mysqld': mysqld. as a service to see any error messages regarding the starting of the MySQL server as a service. See *Note windows-start-service::. The following examples show other common error messages you may encounter when installing MySQL and starting the server for the first time: * If the MySQL server cannot find the `mysql' privileges database or other critical files, you may see these messages: System error 1067 has occurred. Fatal error: Can't open privilege tables: Table 'mysql.host' doesn't exist These messages often occur when the MySQL base or data directories are installed in different locations than the default locations (`C:\Program Files\MySQL\MySQL Server 5.1' and `C:\Program Files\MySQL\MySQL Server 5.1\data', respectively). This situation may occur when MySQL is upgraded and installed to a new location, but the configuration file is not updated to reflect the new location. In addition, there may be old and new configuration files that conflict. Be sure to delete or rename any old configuration files when upgrading MySQL. If you have installed MySQL to a directory other than `C:\Program Files\MySQL\MySQL Server 5.1', you need to ensure that the MySQL server is aware of this through the use of a configuration (`my.ini') file. The `my.ini' file needs to be located in your Windows directory, typically `C:\WINDOWS'. You can determine its exact location from the value of the `WINDIR' environment variable by issuing the following command from the command prompt: C:\> echo %WINDIR% An option file can be created and modified with any text editor, such as Notepad. For example, if MySQL is installed in `E:\mysql' and the data directory is `D:\MySQLdata', you can create the option file and set up a `[mysqld]' section to specify values for the `basedir' and `datadir' options: [mysqld] # set basedir to your installation path basedir=E:/mysql # set datadir to the location of your data directory datadir=D:/MySQLdata Note that Windows path names are specified in option files using (forward) slashes rather than backslashes. If you do use backslashes, double them: [mysqld] # set basedir to your installation path basedir=C:\\Program Files\\MySQL\\MySQL Server 5.1 # set datadir to the location of your data directory datadir=D:\\MySQLdata The rules for use of backslash in option file values are given in *Note option-files::. If you change the `datadir' value in your MySQL configuration file, you must move the contents of the existing MySQL data directory before restarting the MySQL server. See *Note windows-create-option-file::. * If you reinstall or upgrade MySQL without first stopping and removing the existing MySQL service and install MySQL using the MySQL Config Wizard, you may see this error: Error: Cannot create Windows service for MySql. Error: 0 This occurs when the Config Wizard tries to install the service and finds an existing service with the same name. One solution to this problem is to choose a service name other than `mysql' when using the configuration wizard. This enables the new service to be installed correctly, but leaves the outdated service in place. Although this is harmless, it is best to remove old services that are no longer in use. To permanently remove the old `mysql' service, execute the following command as a user with administrative privileges, on the command-line: C:\> sc delete mysql [SC] DeleteService SUCCESS If the `sc' utility is not available for your version of Windows, download the `delsrv' utility from `http://www.microsoft.com/windows2000/techinfo/reskit/tools/existing/delsrv-o.asp' and use the `delsrv mysql' syntax.  File: manual.info, Node: windows-upgrading, Next: windows-postinstallation, Prev: windows-troubleshooting, Up: windows-installation 3.3.7 Upgrading MySQL Server on Microsoft Windows ------------------------------------------------- This section lists some of the steps you should take when upgrading MySQL on Windows. 1. Review *Note upgrading::, for additional information on upgrading MySQL that is not specific to Windows. 2. You should always back up your current MySQL installation before performing an upgrade. See *Note backup-methods::. 3. Download the latest Windows distribution of MySQL from `http://dev.mysql.com/downloads/'. 4. Before upgrading MySQL, you must stop the server. If the server is installed as a service, stop the service with the following command from the command prompt: C:\> NET STOP MySQL If you are not running the MySQL server as a service, use *Note `mysqladmin': mysqladmin. to stop it. For example, before upgrading from MySQL 5.0 to 5.1, use *Note `mysqladmin': mysqladmin. from MySQL 5.0 as follows: C:\> "C:\Program Files\MySQL\MySQL Server 5.0\bin\mysqladmin" -u root shutdown *Note*: If the MySQL `root' user account has a password, you need to invoke *Note `mysqladmin': mysqladmin. with the `-p' option and supply the password when prompted. 5. Before upgrading to MySQL 5.1 from a version previous to 4.1.5, or from a version of MySQL installed from a Zip archive to a version of MySQL installed with the MySQL Installation Wizard, you must first manually remove the previous installation and MySQL service (if the server is installed as a service). To remove the MySQL service, use the following command: C:\> C:\mysql\bin\mysqld --remove *Important*: If you do not remove the existing service, the MySQL Installation Wizard may fail to properly install the new MySQL service. 6. When upgrading from MySQL 5.1.23 to MySQL 5.1.24, the change in the default location of the data directory from a directory within the MySQL installation to the `AppData' folder means that you must manually copy the data files from your old installation to the new location. 7. If you are using the MySQL Installation Wizard, start the wizard as described in *Note windows-install-wizard::. 8. If you are installing MySQL from a Zip archive, extract the archive. You may either overwrite your existing MySQL installation (usually located at `C:\mysql'), or install it into a different directory, such as `C:\mysql5'. Overwriting the existing installation is recommended. 9. If you were running MySQL as a Windows service and you had to remove the service earlier in this procedure, reinstall the service. (See *Note windows-start-service::.) 10. Restart the server. For example, use `NET START MySQL' if you run MySQL as a service, or invoke *Note `mysqld': mysqld. directly otherwise. 11. As Administrator, run *Note `mysql_upgrade': mysql-upgrade. to check your tables, attempt to repair them if necessary, and update your grant tables if they have changed so that you can take advantage of any new capabilities. See *Note mysql-upgrade::. 12. If you encounter errors, see *Note windows-troubleshooting::.  File: manual.info, Node: windows-postinstallation, Prev: windows-upgrading, Up: windows-installation 3.3.8 MySQL Server on Microsoft Windows Postinstallation Procedures ------------------------------------------------------------------- On Windows, you need not create the data directory and the grant tables. MySQL Windows distributions include the grant tables with a set of preinitialized accounts in the `mysql' database under the data directory. Regarding passwords, if you installed MySQL using the Windows Installation Wizard, you may have already assigned passwords to the accounts. (See *Note windows-install-wizard::.) Otherwise, use the password-assignment procedure given in *Note default-privileges::. Before setting up passwords, you might want to try running some client programs to make sure that you can connect to the server and that it is operating properly. Make sure that the server is running (see *Note windows-server-first-start::), and then issue the following commands to verify that you can retrieve information from the server. You may need to specify directory different from `C:\mysql\bin' on the command line. If you used the Windows Installation Wizard, the default directory is `C:\Program Files\MySQL\MySQL Server 5.1', and the *Note `mysql': mysql. and *Note `mysqlshow': mysqlshow. client programs are in `C:\Program Files\MySQL\MySQL Server 5.1\bin'. See *Note windows-install-wizard::, for more information. Use *Note `mysqlshow': mysqlshow. to see what databases exist: C:\> C:\mysql\bin\mysqlshow +--------------------+ | Databases | +--------------------+ | information_schema | | mysql | | test | +--------------------+ The list of installed databases may vary, but will always include the minimum of `mysql' and `information_schema'. In most cases, the `test' database will also be installed automatically. The preceding command (and commands for other MySQL programs such as *Note `mysql': mysql.) may not work if the correct MySQL account does not exist. For example, the program may fail with an error, or you may not be able to view all databases. If you installed using the MSI packages and used the MySQL Server Instance Config Wizard, then the `root' user will have been created automatically with the password you supplied. In this case, you should use the `-u root' and `-p' options. (You will also need to use the `-u root' and `-p' options if you have already secured the initial MySQL accounts.) With `-p', you will be prompted for the `root' password. For example: C:\> C:\mysql\bin\mysqlshow -u root -p Enter password: (ENTER ROOT PASSWORD HERE) +--------------------+ | Databases | +--------------------+ | information_schema | | mysql | | test | +--------------------+ If you specify a database name, *Note `mysqlshow': mysqlshow. displays a list of the tables within the database: C:\> C:\mysql\bin\mysqlshow mysql Database: mysql +---------------------------+ | Tables | +---------------------------+ | columns_priv | | db | | event | | func | | help_category | | help_keyword | | help_relation | | help_topic | | host | | plugin | | proc | | procs_priv | | servers | | tables_priv | | time_zone | | time_zone_leap_second | | time_zone_name | | time_zone_transition | | time_zone_transition_type | | user | +---------------------------+ Use the *Note `mysql': mysql. program to select information from a table in the `mysql' database: C:\> C:\mysql\bin\mysql -e "SELECT Host,Db,User FROM mysql.db" +------+--------+------+ | host | db | user | +------+--------+------+ | % | test | | | % | test_% | | +------+--------+------+ For more information about *Note `mysqlshow': mysqlshow. and *Note `mysql': mysql, see *Note mysqlshow::, and *Note mysql::. If you are running a version of Windows that supports services, you can set up the MySQL server to run automatically when Windows starts. See *Note windows-start-service::.  File: manual.info, Node: macosx-installation, Next: linux-installation, Prev: windows-installation, Up: installing 3.4 Installing MySQL on Mac OS X ================================ * Menu: * macosx-installation-notes:: General Notes on Installing MySQL on Mac OS X * macosx-installation-pkg:: Installing MySQL on Mac OS X Using Native Packages * macosx-installation-startupitem:: Installing the MySQL Startup Item * macosx-installation-prefpane:: Installing and Using the MySQL Preference Pane * macosx-installation-server:: Using the Bundled MySQL on Mac OS X Server MySQL for Mac OS X is available in a number of different forms: * Native Package Installer format, which uses the native Mac OS X installer to walk you through the installation of MySQL. For more information, see *Note macosx-installation-pkg::. You can use the package installer with Mac OS X 10.3 and later, and the package is available for both PowerPC and Intel architectures, and 32-bit and 64-bit architectures. There is no Universal Binary available using the package installation method. The user you use to perform the installation must have administrator privileges. * Tar package format, which uses a file packaged using the Unix `tar' and `gzip' commands. To use this method, you will need to open a `Terminal' window. You do not need administrator privileges using this method, as you can install the MySQL server anywhere using this method. For more information on using this method, you can use the generic instructions for using a tarball, *Note binary-installation::.You can use the package installer with Mac OS X 10.3 and later, and available for both PowerPC and Intel architectures, and both 32-bit and 64-bit architectures. A Universal Binary, incorporating both Power PC and Intel architectures and 32-bit and 64-bit binaries is available. In addition to the core installation, the Package Installer also includes *Note macosx-installation-startupitem:: and *Note macosx-installation-prefpane::, both of which simplify the management of your installation. * Mac OS X server includes a version of MySQL as standard. If you want to use a more recent version than that supplied with the Mac OS X server release, you can make use of the package or tar formats. For more information on using the MySQL bundled with Mac OS X, see *Note macosx-installation-server::. For additional information on using MySQL on Mac OS X, see *Note macosx-installation-notes::.  File: manual.info, Node: macosx-installation-notes, Next: macosx-installation-pkg, Prev: macosx-installation, Up: macosx-installation 3.4.1 General Notes on Installing MySQL on Mac OS X --------------------------------------------------- You should keep the following issues and notes in mind: * The default location for the MySQL Unix socket is different on Mac OS X and Mac OS X Server depending on the installation type you chose. The following table shows the default locations by installation type. *MySQL Unix Socket Locations on Mac OS X by Installation Type* Installation Type Socket Location Package Installer `/tmp/mysql.sock' from MySQL Tarball from MySQL `/tmp/mysql.sock' MySQL Bundled with `/var/mysql/mysql.sock' Mac OS X Server To prevent issues, you should either change the configuration of the socket used within your application (for example, changing `php.ini'), or you should configure the socket location using a MySQL configuration file and the `socket' option. For more information, see *Note server-options::. * You may need (or want) to create a specific `mysql' user to own the MySQL directory and data. On Mac OS X 10.4 and lower you can do this by using the `Netinfo Manager' application, located within the `Utilities' folder within the `Applications' folder. On Mac OS X 10.5 and later you can do this through the `Directory Utility'. From Mac OS X 10.5 and later (including Mac OS X Server 10.5) the `mysql' should already exist. For use in single user mode, an entry for `_mysql' (note the underscore prefix) should already exist within the system `/etc/passwd' file. * Due to a bug in the Mac OS X package installer, you may see this error message in the destination disk selection dialog: You cannot install this software on this disk. (null) If this error occurs, click the `Go Back' button once to return to the previous screen. Then click `Continue' to advance to the destination disk selection again, and you should be able to choose the destination disk correctly. We have reported this bug to Apple and it is investigating this problem. * Because the MySQL package installer installs the MySQL contents into a version and platform specific directory, you can use this to upgrade and migrate your database between versions. You will need to either copy the `data' directory from the old version to the new version, or alternatively specify an alternative `datadir' value to set location of the data directory. * You might want to add aliases to your shell's resource file to make it easier to access commonly used programs such as *Note `mysql': mysql. and *Note `mysqladmin': mysqladmin. from the command line. The syntax for `bash' is: alias mysql=/usr/local/mysql/bin/mysql alias mysqladmin=/usr/local/mysql/bin/mysqladmin For `tcsh', use: alias mysql /usr/local/mysql/bin/mysql alias mysqladmin /usr/local/mysql/bin/mysqladmin Even better, add `/usr/local/mysql/bin' to your `PATH' environment variable. You can do this by modifying the appropriate startup file for your shell. For more information, see *Note invoking-programs::. * After you have copied over the MySQL database files from the previous installation and have successfully started the new server, you should consider removing the old installation files to save disk space. Additionally, you should also remove older versions of the Package Receipt directories located in `/Library/Receipts/mysql-VERSION.pkg'.  File: manual.info, Node: macosx-installation-pkg, Next: macosx-installation-startupitem, Prev: macosx-installation-notes, Up: macosx-installation 3.4.2 Installing MySQL on Mac OS X Using Native Packages -------------------------------------------------------- You can install MySQL on Mac OS X 10.3.x (`Panther') or newer using a Mac OS X binary package in PKG format instead of the binary tarball distribution. Please note that older versions of Mac OS X (for example, 10.1.x or 10.2.x) are _not_ supported by this package. The package is located inside a disk image (`.dmg') file that you first need to mount by double-clicking its icon in the Finder. It should then mount the image and display its contents. *Note*: Before proceeding with the installation, be sure to stop all running MySQL server instances by using either the MySQL Manager Application (on Mac OS X Server) or *Note `mysqladmin shutdown': mysqladmin. on the command line. When installing from the package version, you should also install the MySQL Preference Pane, which will enable you to control the startup and execution of your MySQL server from System Preferences. For more information, see *Note macosx-installation-prefpane::. When installing using the package installer, the files are installed into a directory within `/usr/local' matching the name of the installation version and platform. For example, the installer file `mysql-5.1.39-osx10.5-x86_64.pkg' installs MySQL into `/usr/local/mysql-5.1.39-osx10.5-x86_64 '. The following table shows the layout of the installation directory. *MySQL Installation Layout on Mac OS X* Directory Contents of Directory `bin' Client programs and the *Note `mysqld': mysqld. server `data' Log files, databases `docs' Manual in Info format `include' Include (header) files `lib' Libraries `man' Unix manual pages `mysql-test' MySQL test suite `scripts' *Note `mysql_install_db': mysql-install-db. `share' Miscellaneous support files, including error messages, sample configuration files, SQL for database installation `sql-bench' Benchmarks `support-files' Scripts and sample configuration files `/tmp/mysql.sock' Location of the MySQL Unix socket During the package installer process, a symbolic link from `/usr/local/mysql' to the version/platform specific directory created during installation will be created automatically. 1. Download and open the MySQL package installer, which is provided on a disk image (`.dmg') that includes the main MySQL installation package, the `MySQLStartupItem.pkg' installation package, and the `MySQL.prefPane'. Double-click the disk image to open it. 2. Double-click the MySQL installer package. It will be named according to the version of MySQL you have downloaded. For example, if you have downloaded MySQL 5.1.39, double-click `mysql-5.1.39-osx10.5-x86.pkg'. 3. You will be presented with the opening installer dialog. Click `Continue' to begin installation. MySQL Package Installer: Step 1 4. A copy of the installation instructions and other important information relevant to this installation are displayed. Click `Continue' . 5. If you have downloaded the community version of MySQL, you will be shown a copy of the relevant GNU General Public License. Click `Continue' . 6. Select the drive you want to use to install the MySQL Startup Item. The drive must have a valid, bootable, Mac OS X operating system installed. Click `Continue'. MySQL Package Installer: Step 4 7. You will be asked to confirm the details of the installation, including the space required for the installation. To change the drive on which the startup item is installed, click either `Go Back' or `Change Install Location...'. To install the startup item, click `Install'. 8. Once the installation has been completed successfully, you will be shown an `Install Succeeded' message. For convenience, you may also want to install the startup item and preference pane. See *Note macosx-installation-startupitem::, and *Note macosx-installation-prefpane::.  File: manual.info, Node: macosx-installation-startupitem, Next: macosx-installation-prefpane, Prev: macosx-installation-pkg, Up: macosx-installation 3.4.3 Installing the MySQL Startup Item --------------------------------------- The MySQL Installation Package includes a startup item that can be used to automatically start and stop MySQL. To install the MySQL Startup Item: 1. Download and open the MySQL package installer, which is provided on a disk image (`.dmg') that includes the main MySQL installation package, the `MySQLStartupItem.pkg' installation package, and the `MySQL.prefPane'. Double-click the disk image to open it. 2. Double-click the `MySQLStartItem.pkg' file to start the installation process. 3. You will be presented with the `Install MySQL Startup Item' dialog. MySQL Startup Item Installer: Step 1 Click `Continue' to continue the installation process. 4. A copy of the installation instructions and other important information relevant to this installation are displayed. Click `Continue' . 5. Select the drive you want to use to install the MySQL Startup Item. The drive must have a valid, bootable, Mac OS X operating system installed. Click `Continue'. MySQL Startup Item Installer: Step 3 6. You will be asked to confirm the details of the installation. To change the drive on which the startup item is installed, click either `Go Back' or `Change Install Location...'. To install the startup item, click `Install'. 7. Once the installation has been completed successfully, you will be shown an `Install Succeeded' message. MySQL Startup Item Installer: Step 5 The Startup Item for MySQL is installed into `/Library/StartupItems/MySQLCOM'. The Startup Item installation adds a variable `MYSQLCOM=-YES-' to the system configuration file `/etc/hostconfig'. If you want to disable the automatic startup of MySQL, change this variable to `MYSQLCOM=-NO-'. After the installation, you can start and stop MySQL by running the following commands in a terminal window. You must have administrator privileges to perform these tasks, and you may be prompted for your password. If you have installed the Startup Item, use this command to start the server: shell> sudo /Library/StartupItems/MySQLCOM/MySQLCOM start If you have installed the Startup Item, use this command to stop the server: shell> sudo /Library/StartupItems/MySQLCOM/MySQLCOM stop  File: manual.info, Node: macosx-installation-prefpane, Next: macosx-installation-server, Prev: macosx-installation-startupitem, Up: macosx-installation 3.4.4 Installing and Using the MySQL Preference Pane ---------------------------------------------------- The MySQL Package installer disk image also includes a custom MySQL Preference Pane that enables you to start, stop, and control automated startup during boot of your MySQL installation. To install the MySQL Preference Pane: 1. Download and open the MySQL package installer package, which is provided on a disk image (`.dmg') that includes the main MySQL installation package, the `MySQLStartupItem.pkg' installation package, and the `MySQL.prefPane'. Double-click the disk image to open it. 2. Double-click the `MySQL.prefPane'. The MySQL System Preferences will open. 3. If this is the first time you have installed the preference pane, you will be asked to confirm installation and whether you want to install the preference pane for all users, or only the current user. To install the preference pane for all users you will need administrator privileges. If necessary, you will be prompted for the username and password for a user with administrator privileges. 4. If you already have the MySQL Preference Pane installed, you will be asked to confirm whether you want to overwrite the existing MySQL Preference Pane. *Note*: The MySQL Preference Pane only starts and stops MySQL installation installed from the MySQL package installation that have been installed in the default location. Once the MySQL Preference Pane has been installed, you can control your MySQL server instance using the preference pane. To use the preference pane, open the `System Preferences...' from the Apple menu. Select the MySQL preference pane by clicking the MySQL logo within the `Other' section of the preference panes list. MySQL Preference Pane The MySQL Preference Pane shows the current status of the MySQL server, showing `stopped' (in red) if the server is not running and `running' (in green) if the server has already been started. The preference pane also shows the current setting for whether the MySQL server has been set to start automatically. * *To start MySQL using the preference pane: * Click `Start MySQL Server'. You may be prompted for the username and password of a user with administrator privileges to start the MySQL server. * *To stop MySQL using the preference pane: * Click `Stop MySQL Server'. You may be prompted for the username and password of a user with administrator privileges to stop the MySQL server. * *To automatically start the MySQL server when the system boots:* Check the check box next to `Automatically Start MySQL Server on Startup'. * *To disable automatic MySQL server startup when the system boots:* Uncheck the check box next to `Automatically Start MySQL Server on Startup'. You can close the `System Preferences...' window once you have completed your settings.  File: manual.info, Node: macosx-installation-server, Prev: macosx-installation-prefpane, Up: macosx-installation 3.4.5 Using the Bundled MySQL on Mac OS X Server ------------------------------------------------ If you are running Mac OS X Server, a version of MySQL should already be installed. The following table shows the versions of MySQL that ship with Mac OS X Server versions. *MySQL Versions Preinstalled with Mac OS X Server* Mac OS X Server MySQL Version Version 10.2-10.2.2 3.23.51 10.2.3-10.2.6 3.23.53 10.3 4.0.14 10.3.2 4.0.16 10.4.0 4.1.10a 10.5.0 5.0.45 10.6.0 5.0.82 The following table shows the installation layout of MySQL on Mac OS X Server. *MySQL Directory Layout for Preinstalled MySQL installations on Mac OS X Server* Directory Contents of Directory `/usr/bin' Client programs `/var/mysql' Log files, databases `/usr/libexec' The *Note `mysqld': mysqld. server `/usr/share/man' Unix manual pages `/usr/share/mysql/mysql-test'MySQL test suite `/usr/share/mysql' Miscellaneous support files, including error messages, character set files, sample configuration files, SQL for database installation `/var/mysql/mysql.sock' Location of the MySQL Unix socket * Additional Resources * * For more information on managing the bundled MySQL instance in Mac OS X Server 10.5, see Mac OS X Server: Web Technologies Administration For Version 10.5 Leopard (http://images.apple.com/server/macosx/docs/Web_Technologies_Admin_v10.5.pdf). * For more information on managing the bundled MySQL instance in Mac OS X Server 10.6, see Mac OS X Server: Web Technologies Administration Version 10.6 Snow Leopard (http://manuals.info.apple.com/en_US/WebTech_v10.6.pdf). * The MySQL server bundled with Mac OS X Server does not include the MySQL client libraries and header files required to access and use MySQL from a third-party driver, such as Perl DBI or PHP. For more information on obtaining and installing MySQL libraries, see Mac OS X Server version 10.5: MySQL libraries available for download (http://support.apple.com/kb/TA25017). Alternatively, you can ignore the bundled MySQL server and install MySQL from the package or tarball installation.  File: manual.info, Node: linux-installation, Next: solaris-installation, Prev: macosx-installation, Up: installing 3.5 Installing MySQL on Linux ============================= * Menu: * linux-installation-rpm:: Installing MySQL from RPM Packages on Linux * linux-installation-native:: Installing MySQL on Linux using Native Package Manager Linux supports a number of different solutions for installing MySQL. The recommended method is to use one of the distributions from Oracle. If you choose this method, there are three options available: * Installing from a generic binary package in `.tar.gz' format. See *Note binary-installation:: for more information. * Extracting and compiling MySQL from a source distribution. For detailed instructions, see *Note source-installation::. * Installing using a pre-compiled RPM package. For more information on using the RPM solution, see *Note linux-installation-rpm::. As an alternative, you can use the native package manager within your Linux distribution to automatically download and install MySQL for you. Native package installations can take of the download and dependencies required to run MySQL, but the MySQL version will often be some way behind the currently available release. You will also normally be unable to install developmental releases, as these are not usually made available in the native repository. For more information on using the native package installers, see *Note linux-installation-native::. *Note*: For many Linux installations, you will want to set up MySQL to be started automatically when your machine starts. Many of the native package installations perform this operation for you, but for source, binary and RPM solutions you may need to set this up separately. The required script, *Note `mysql.server': mysql-server, can be found in the `support-files' directory under the MySQL installation directory or in a MySQL source tree. You can install it as `/etc/init.d/mysql' for automatic MySQL startup and shutdown. See *Note automatic-start::.  File: manual.info, Node: linux-installation-rpm, Next: linux-installation-native, Prev: linux-installation, Up: linux-installation 3.5.1 Installing MySQL from RPM Packages on Linux ------------------------------------------------- The recommended way to install MySQL on RPM-based Linux distributions is by using the RPM packages. The RPMs that we provide to the community should work on all versions of Linux that support RPM packages and use `glibc' 2.3. To obtain RPM packages, see *Note getting-mysql::. For non-RPM Linux distributions, you can install MySQL using a `.tar.gz' package. See *Note binary-installation::. Installations created from our Linux RPM distributions result in files under the following system directories. *MySQL Installation Layout for Linux RPM* Directory Contents of Directory `/usr/bin' Client programs and scripts `/usr/sbin' The *Note `mysqld': mysqld. server `/var/lib/mysql' Log files, databases `/usr/share/info' Manual in Info format `/usr/share/man' Unix manual pages `/usr/include/mysql' Include (header) files `/usr/lib/mysql' Libraries `/usr/share/mysql' Miscellaneous support files, including error messages, character set files, sample configuration files, SQL for database installation `/usr/share/sql-bench' Benchmarks *Note*: RPM distributions of MySQL often are provided by other vendors. Be aware that they may differ in features and capabilities from those built by us, and that the instructions in this manual do not necessarily apply to installing them. The vendor's instructions should be consulted instead. In most cases, you need to install only the `MySQL-server' and `MySQL-client' packages to get a functional MySQL installation. The other packages are not required for a standard installation. RPMs for MySQL Cluster Beginning with MySQL 5.1.24, standard MySQL server RPMs built by MySQL no longer provide support for the *Note `NDBCLUSTER': mysql-cluster. storage engine. MySQL Cluster users wanting to upgrade MySQL 5.1.23 or earlier installations from RPMs built by MySQL should upgrade to MySQL Cluster NDB 6.2 or MySQL Cluster NDB 6.3; RPMs that should work with most Linux distributions are available for both of these release series. *Important*: When upgrading a MySQL Cluster RPM installation, you must upgrade _all_ installed RPMs, including the `Server' and `Client' RPMs. For more information about installing MySQL Cluster from RPMs, see *Note mysql-cluster-install-linux-rpm::. For upgrades, if your installation was originally produced by installing multiple RPM packages, it is best to upgrade all the packages, not just some. For example, if you previously installed the server and client RPMs, do not upgrade just the server RPM. The RPM packages shown in the following list are available. The names shown here use a suffix of `.glibc23.i386.rpm', but particular packages can have different suffixes, described later. * `MySQL-server-VERSION.glibc23.i386.rpm' The MySQL server. You need this unless you only want to connect to a MySQL server running on another machine. * `MySQL-client-VERSION.glibc23.i386.rpm' The standard MySQL client programs. You probably always want to install this package. * `MySQL-devel-VERSION.glibc23.i386.rpm' The libraries and include files that are needed if you want to compile other MySQL clients, such as the Perl modules. * `MySQL-debuginfo-VERSION.glibc23.i386.rpm' This package contains debugging information. `debuginfo' RPMs are never needed to use MySQL software; this is true both for the server and for client programs. However, they contain additional information that might be needed by a debugger to analyze a crash. * `MySQL-shared-VERSION.glibc23.i386.rpm' This package contains the shared libraries (`libmysqlclient.so*') that certain languages and applications need to dynamically load and use MySQL. It contains single-threaded and thread-safe libraries. If you install this package, do not install the `MySQL-shared-compat' package. * `MySQL-shared-compat-VERSION.glibc23.i386.rpm' This package includes the shared libraries for MySQL 3.23, 4.0, and so on, up to the current release. It contains single-threaded and thread-safe libraries. Install this package instead of `MySQL-shared' if you have applications installed that are dynamically linked against older versions of MySQL but you want to upgrade to the current version without breaking the library dependencies. * `MySQL-shared-compat-advanced-gpl-VERSION.glibc23.i386.rpm', `MySQL-shared-compat-advanced-VERSION.glibc23.i386.rpm' These are like the `MySQL-shared-compat' package, but are for the `MySQL Enterprise Server - Advanced Edition' products. Install these packages rather than the normal `MySQL-shared-compat' package if you want to included shared client libraries for older MySQL versions. * `MySQL-embedded-VERSION.glibc23.i386.rpm' The embedded MySQL server library. * `MySQL-ndb-management-VERSION.glibc23.i386.rpm', `MySQL-ndb-storage-VERSION.glibc23.i386.rpm', `MySQL-ndb-tools-VERSION.glibc23.i386.rpm', `MySQL-ndb-extra-VERSION.glibc23.i386.rpm' Packages that contain additional files for MySQL Cluster installations. *Note*: The `MySQL-ndb-tools' RPM requires a working installation of perl. Prior to MySQL 5.1.18, the `DBI' and `HTML::Template' packages were also required. See *Note perl-support::, and *Note mysql-cluster-programs-ndb-size-pl::, for more information. * `MySQL-test-VERSION.glibc23.i386.rpm' This package includes the MySQL test suite. * `MySQL-VERSION.src.rpm' This contains the source code for all of the previous packages. It can also be used to rebuild the RPMs on other architectures (for example, Alpha or SPARC). The suffix of RPM package names (following the VERSION value) has the following syntax: .PLATFORM.CPU.rpm The PLATFORM and CPU values indicate the type of system for which the package is built. PLATFORM indicates the platform and CPU indicates the processor type or family. All packages are dynamically linked against `glibc' 2.3. The PLATFORM value indicates whether the package is platform independent or intended for a specific platform, as shown in the following table. *MySQL Linux Installation Packages* PLATFORM Value Intended Use `glibc23' Platform independent, should run on any Linux distribution that supports `glibc' 2.3 `rhel3', `rhel4' Red Hat Enterprise Linux 3 or 4 `sles9', `sles10' SuSE Linux Enterprise Server 9 or 10 In MySQL 5.1, only `glibc23' packages are available currently. The CPU value indicates the processor type or family for which the package is built. *MySQL Installation Packages for Linux CPU Identifier* CPU Value Intended Processor Type or Family `i386' x86 processor, 386 and up `i586' x86 processor, Pentium and up `x86_64' 64-bit x86 processor `ia64' Itanium (IA-64) processor To see all files in an RPM package (for example, a `MySQL-server' RPM), run a command like this: shell> rpm -qpl MySQL-server-VERSION.glibc23.i386.rpm To perform a standard minimal installation, install the server and client RPMs: shell> rpm -i MySQL-server-VERSION.glibc23.i386.rpm shell> rpm -i MySQL-client-VERSION.glibc23.i386.rpm To install only the client programs, install just the client RPM: shell> rpm -i MySQL-client-VERSION.glibc23.i386.rpm RPM provides a feature to verify the integrity and authenticity of packages before installing them. If you would like to learn more about this feature, see *Note verifying-package-integrity::. The server RPM places data under the `/var/lib/mysql' directory. The RPM also creates a login account for a user named `mysql' (if one does not exist) to use for running the MySQL server, and creates the appropriate entries in `/etc/init.d/' to start the server automatically at boot time. (This means that if you have performed a previous installation and have made changes to its startup script, you may want to make a copy of the script so that you do not lose it when you install a newer RPM.) See *Note automatic-start::, for more information on how MySQL can be started automatically on system startup. If you want to install the MySQL RPM on older Linux distributions that do not support initialization scripts in `/etc/init.d' (directly or through a symlink), you should create a symbolic link that points to the location where your initialization scripts actually are installed. For example, if that location is `/etc/rc.d/init.d', use these commands before installing the RPM to create `/etc/init.d' as a symbolic link that points there: shell> cd /etc shell> ln -s rc.d/init.d . However, all current major Linux distributions should support the new directory layout that uses `/etc/init.d', because it is required for LSB (Linux Standard Base) compliance. In MySQL 5.1.49 and later, during an upgrade installation using the RPM packages, if the MySQL server is running when the upgrade occurs, the MySQL server is stopped, the upgrade occurs, and the MySQL server is restarted. If the MySQL server is not already running when the RPM upgrade occurs, the MySQL server is not started at the end of the installation. If something goes wrong, you can find more information in the binary installation section. See *Note binary-installation::. *Note*: The accounts that are listed in the MySQL grant tables initially have no passwords. After starting the server, you should set up passwords for them using the instructions in *Note postinstallation::. During RPM installation, a user named `mysql' and a group named `mysql' are created on the system. This is done using the `useradd', `groupadd', and `usermod' commands. Those commands require appropriate administrative privileges, which is required for locally managed users and groups (as listed in the `/etc/passwd' and `/etc/group' files) by the RPM installation process being run by `root'. If you log in as the `mysql' user, you may find that MySQL displays `Invalid (old?) table or database name' errors that mention `.mysqlgui', `lost+found', `.mysqlgui', `.bash_history', `.fonts.cache-1', `.lesshst', `.mysql_history', `.profile', `.viminfo', and similar files created by MySQL or operating system utilities. You can safely ignore these error messages or remove the files or directories that cause them if you do not need them. For nonlocal user management (LDAP, NIS, and so forth), the administrative tools may require additional authentication (such as a password), and will fail if the installing user does not provide this authentication. Even if they fail, the RPM installation will not abort but succeed, and this is intentional. If they failed, some of the intended transfer of ownership may be missing, and it is recommended that the system administrator then manually ensures some appropriate user and group exists and manually transfers ownership following the actions in the RPM spec file.  File: manual.info, Node: linux-installation-native, Prev: linux-installation-rpm, Up: linux-installation 3.5.2 Installing MySQL on Linux using Native Package Manager ------------------------------------------------------------ Many Linux distributions include a version of the MySQL server, client tools, and development components into the standard package management system built into distributions such as Fedora, Debian, Ubuntu, and Gentoo. This section provides basic instructions for installing MySQL using these systems. *Important*: Native package installations can take care of the download and dependencies required to run MySQL, but the MySQL version will often be some way behind the currently available release. You will also normally be unable to install developmental releases, as these are not usually made available in the native repository. Distribution specific instructions are shown below: * *Red Hat Linux, Fedora, CentOS* For Red Hat and similar distributions, the MySQL distribution is divided into a number of separate packages, `mysql' for the client tools, `mysql-server' for the server and associated tools, and `mysql-libs' for the libraries. The libraries are required if you want to provide connectivity from different languages and environments such as Perl, Python and others. To install, use the `yum' command to specify the packages that you want to install. For example: root-shell> yum install mysql mysql-server mysql-libs mysql-server Loaded plugins: presto, refresh-packagekit Setting up Install Process Resolving Dependencies --> Running transaction check ---> Package mysql.x86_64 0:5.1.48-2.fc13 set to be updated ---> Package mysql-libs.x86_64 0:5.1.48-2.fc13 set to be updated ---> Package mysql-server.x86_64 0:5.1.48-2.fc13 set to be updated --> Processing Dependency: perl-DBD-MySQL for package: mysql-server-5.1.48-2.fc13.x86_64 --> Running transaction check ---> Package perl-DBD-MySQL.x86_64 0:4.017-1.fc13 set to be updated --> Finished Dependency Resolution Dependencies Resolved ================================================================================ Package Arch Version Repository Size ================================================================================ Installing: mysql x86_64 5.1.48-2.fc13 updates 889 k mysql-libs x86_64 5.1.48-2.fc13 updates 1.2 M mysql-server x86_64 5.1.48-2.fc13 updates 8.1 M Installing for dependencies: perl-DBD-MySQL x86_64 4.017-1.fc13 updates 136 k Transaction Summary ================================================================================ Install 4 Package(s) Upgrade 0 Package(s) Total download size: 10 M Installed size: 30 M Is this ok [y/N]: y Downloading Packages: Setting up and reading Presto delta metadata Processing delta metadata Package(s) data still to download: 10 M (1/4): mysql-5.1.48-2.fc13.x86_64.rpm | 889 kB 00:04 (2/4): mysql-libs-5.1.48-2.fc13.x86_64.rpm | 1.2 MB 00:06 (3/4): mysql-server-5.1.48-2.fc13.x86_64.rpm | 8.1 MB 00:40 (4/4): perl-DBD-MySQL-4.017-1.fc13.x86_64.rpm | 136 kB 00:00 -------------------------------------------------------------------------------- Total 201 kB/s | 10 MB 00:52 Running rpm_check_debug Running Transaction Test Transaction Test Succeeded Running Transaction Installing : mysql-libs-5.1.48-2.fc13.x86_64 1/4 Installing : mysql-5.1.48-2.fc13.x86_64 2/4 Installing : perl-DBD-MySQL-4.017-1.fc13.x86_64 3/4 Installing : mysql-server-5.1.48-2.fc13.x86_64 4/4 Installed: mysql.x86_64 0:5.1.48-2.fc13 mysql-libs.x86_64 0:5.1.48-2.fc13 mysql-server.x86_64 0:5.1.48-2.fc13 Dependency Installed: perl-DBD-MySQL.x86_64 0:4.017-1.fc13 Complete! MySQL and the MySQL server should now be installed. A sample configuration file is installed into `/etc/my.cnf'. An init script, to start and stop the server, will have been installed into `/etc/init.d/mysqld'. To start the MySQL server use `service': root-shell> service mysqld start To enable the server to be started and stopped automatically during boot, use `chkconfig': root-shell> chkconfig --levels 235 mysqld on Which enables the MySQL server to be started (and stopped) automatically at the specified the run levels. The database tables will have been automatically created for you, if they do not already exist. You should, however, run *Note `mysql_secure_installation': mysql-secure-installation. to set the root passwords on your server. * *Debian, Ubuntu, Kubuntu* On Debian and related distributions, there are two packages, `mysql-client' and `mysql-server', for the client and server components respectively. You should specify an explicit version, for example `mysql-client-5.1', to ensure that you install the version of MySQL that you want. To download and install, including any dependencies, use the `apt-get' command, specifying the packages that you want to install. *Note*: Before installing, make sure that you update your `apt-get' index files to ensure you are downloading the latest available version. A sample installation of the MySQL packages might look like this (some sections trimmed for clarity): root-shell> apt-get install mysql-client-5.1 mysql-server-5.1 Reading package lists... Done Building dependency tree Reading state information... Done The following packages were automatically installed and are no longer required: linux-headers-2.6.28-11 linux-headers-2.6.28-11-generic Use 'apt-get autoremove' to remove them. The following extra packages will be installed: bsd-mailx libdbd-mysql-perl libdbi-perl libhtml-template-perl libmysqlclient15off libmysqlclient16 libnet-daemon-perl libplrpc-perl mailx mysql-common postfix Suggested packages: dbishell libipc-sharedcache-perl tinyca procmail postfix-mysql postfix-pgsql postfix-ldap postfix-pcre sasl2-bin resolvconf postfix-cdb The following NEW packages will be installed bsd-mailx libdbd-mysql-perl libdbi-perl libhtml-template-perl libmysqlclient15off libmysqlclient16 libnet-daemon-perl libplrpc-perl mailx mysql-client-5.1 mysql-common mysql-server-5.1 postfix 0 upgraded, 13 newly installed, 0 to remove and 182 not upgraded. Need to get 1907kB/25.3MB of archives. After this operation, 59.5MB of additional disk space will be used. Do you want to continue [Y/n]? Y Get: 1 http://gb.archive.ubuntu.com jaunty-updates/main mysql-common 5.1.30really5.0.75-0ubuntu10.5 [63.6kB] Get: 2 http://gb.archive.ubuntu.com jaunty-updates/main libmysqlclient15off 5.1.30really5.0.75-0ubuntu10.5 [1843kB] Fetched 1907kB in 9s (205kB/s) Preconfiguring packages ... Selecting previously deselected package mysql-common. (Reading database ... 121260 files and directories currently installed.) ... Processing 1 added doc-base file(s)... Registering documents with scrollkeeper... Setting up libnet-daemon-perl (0.43-1) ... Setting up libplrpc-perl (0.2020-1) ... Setting up libdbi-perl (1.607-1) ... Setting up libmysqlclient15off (5.1.30really5.0.75-0ubuntu10.5) ... Setting up libdbd-mysql-perl (4.008-1) ... Setting up libmysqlclient16 (5.1.31-1ubuntu2) ... Setting up mysql-client-5.1 (5.1.31-1ubuntu2) ... Setting up mysql-server-5.1 (5.1.31-1ubuntu2) ... * Stopping MySQL database server mysqld ...done. 100825 11:46:15 InnoDB: Started; log sequence number 0 46409 100825 11:46:15 InnoDB: Starting shutdown... 100825 11:46:17 InnoDB: Shutdown completed; log sequence number 0 46409 100825 11:46:17 [Warning] Forcing shutdown of 1 plugins * Starting MySQL database server mysqld ...done. * Checking for corrupt, not cleanly closed and upgrade needing tables. ... Processing triggers for libc6 ... ldconfig deferred processing now taking place *Note*: The `apt-get' command will install a number of packages, including the MySQL server, in order to provide the typical tools and application environment. This can mean that you install a large number of packages in addition to the main MySQL package. During installation, the initial database will be created, and you will be prompted for the MySQL root password (and confirmation). A configuration file will have been created in `/etc/mysql/my.cnf'. An init script will have been created in `/etc/init.d/mysql'. The server will already be started. You can manually start and stop the server using: root-shell> service mysql [start|stop] The service will automatically be added to the 2, 3 and 4 run levels, with stop scripts in the single, shutdown and restart levels. * *Gentoo Linux* As a source-based distribution, installing MySQL on Gentoo involves downloading the source, patching the Gentoo specifics, and then compiling the MySQL server and installing it. This process is handled automatically by the `emerge' command. Depending on the version of MySQL that you want to install, you may need to unmask the specific version that you want for your chosen platform. The MySQL server and client tools are provided within a single package, `dev-db/mysql'. You can obtain a list of the versions available to install by looking at the portage directory for the package: root-shell> ls /usr/portage/dev-db/mysql/mysql-5.1* mysql-5.1.39-r1.ebuild mysql-5.1.44-r1.ebuild mysql-5.1.44-r2.ebuild mysql-5.1.44-r3.ebuild mysql-5.1.44.ebuild mysql-5.1.45-r1.ebuild mysql-5.1.45.ebuild mysql-5.1.46.ebuild To install a specific MySQL version, you must specify the entire atom. For example: root-shell> emerge =dev-db/mysql-5.1.46 A simpler alternative is to use the `virtual/mysql-5.1' package, which will install the latest version: root-shell> emerge =virtual/mysql-5.1 If the package is masked (because it is not tested or certified for the current platform), use the `ACCEPT_KEYWORDS' environment variable. For example: root-shell> ACCEPT_KEYWORDS="~x86" emerge =virtual/mysql-5.1 After installation, you should create a new database using *Note `mysql_install_db': mysql-install-db, and set the password for the root user on MySQL. You can use the configuration interface to set the password and create the initial database: root-shell> emerge --config =dev-db/mysql-5.1.46 A sample configuration file will have been created for you in `/etc/mysql/my.cnf', and an init script will have been created in `/etc/init.d/mysql'. To enable MySQL to start automatically at the normal (default) run levels, you can use: root-shell> rc-update add default mysql  File: manual.info, Node: solaris-installation, Next: aix-installation, Prev: linux-installation, Up: installing 3.6 Installing MySQL on Solaris and OpenSolaris =============================================== * Menu: * solaris-installation-pkg:: Installing MySQL on Solaris using a Solaris `PKG' * solaris-installation-opensolaris:: Installing MySQL on OpenSolaris using IPS MySQL on Solaris and OpenSolaris is available in a number of different formats. * For information on installing using the native Solaris `PKG' format, see *Note solaris-installation-pkg::. * On OpenSolaris, the standard package repositories include MySQL packages specially built for OpenSolaris that include entries for the Service Management Framework (SMF) to enable control of the installation using the SMF administration commands. For more information, see *Note solaris-installation-opensolaris::. * To use a standard `tar' binary installation, use the notes provided in *Note binary-installation::. Check the notes and hints at the end of this section for Solaris specific notes that you may need before or after installation. * For information on installing MySQL on Solaris or OpenSolaris using a source distribution, first check the Solaris advice, *Note solaris-installation-source::. For detailed instructions on installing from source, see *Note source-installation::. To obtain a binary MySQL distribution for Solaris in tarball or PKG format, `http://dev.mysql.com/downloads/mysql/5.1.html'. Additional notes to be aware of when installing and using MySQL on Solaris: * If you want to use MySQL with the `mysql' user and group, use the `groupadd' and `useradd' commands: groupadd mysql useradd -g mysql mysql * If you install MySQL using a binary tarball distribution on Solaris, you may run into trouble even before you get the MySQL distribution unpacked, as the Solaris `tar' cannot handle long file names. This means that you may see errors when you try to unpack MySQL. If this occurs, you must use GNU `tar' (`gtar') to unpack the distribution. In Solaris 10 and OpenSolaris `gtar' is normally located in `/usr/sfw/bin/gtar', but may not be included in the default path definition. * When using Solaris 10 for x86_64, you should mount any file systems on which you intend to store `InnoDB' files with the `forcedirectio' option. (By default mounting is done without this option.) Failing to do so will cause a significant drop in performance when using the `InnoDB' storage engine on this platform. * If you would like MySQL to start automatically, you can copy `support-files/mysql.server' to `/etc/init.d' and create a symbolic link to it named `/etc/rc3.d/S99mysql.server'. * If too many processes try to connect very rapidly to *Note `mysqld': mysqld, you should see this error in the MySQL log: Error in accept: Protocol error You might try starting the server with the `--back_log=50' option as a workaround for this. * To configure the generation of core files on Solaris you should use the `coreadm' command. Because of the security implications of generating a core on a `setuid()' application, by default, Solaris does not support core files on `setuid()' programs. However, you can modify this behavior using `coreadm'. If you enable `setuid()' core files for the current user, they will be generated using the mode 600 and owned by the superuser.  File: manual.info, Node: solaris-installation-pkg, Next: solaris-installation-opensolaris, Prev: solaris-installation, Up: solaris-installation 3.6.1 Installing MySQL on Solaris using a Solaris `PKG' ------------------------------------------------------- You can install MySQL on Solaris and OpenSolaris using a binary package using the native Solaris PKG format instead of the binary tarball distribution. To use this package, download the corresponding `mysql-VERSION-solaris10-PLATFORM.pkg.gz' file, then decompress it. For example: shell> gunzip mysql-5.1.59-solaris10-x86_64.pkg.gz To install a new package, use `pkgadd' and follow the onscreen prompts. You must have root privileges to perform this operation: shell> pkgadd -d mysql-5.1.59-solaris10-x86_64.pkg The following packages are available: 1 mysql MySQL Community Server (GPL) (i86pc) 5.1.59 Select package(s) you wish to process (or 'all' to process all packages). (default: all) [?,??,q]: The `PKG' installer installs all of the files and tools needed, and then initializes your database if one does not exist. To complete the installation, you should set the root password for MySQL as provided in the instructions at the end of the installation. Alternatively, you can run the *Note `mysql_secure_installation': mysql-secure-installation. script that comes with the installation. The default installation directory is `/opt/mysql'. You can only change the root path of the installation when using `pkgadd', which can be used to install MySQL in a different Solaris zone. If you need to install in a specific directory, use the binary `tar' file. The `pkg' installer copies a suitable startup script for MySQL into `/etc/init.d/mysql'. To enable MySQL to startup and shutdown automatically, you should create a link between this file and the init script directories. For example, to ensure safe startup and shutdown of MySQL you could use the following commands to add the right links: shell> ln /etc/init.d/mysql /etc/rc3.d/S91mysql shell> ln /etc/init.d/mysql /etc/rc0.d/K02mysql To remove MySQL, the installed package name is `mysql'. You can use this in combination with the `pkgrm' command to remove the installation. To upgrade when using the Solaris package file format, you must remove the existing installation before installing the updated package. Removal of the package does not delete the existing database information, only the server, binaries and support files. The typical upgrade sequence is therefore: shell> mysqladmin shutdown shell> pkgrm mysql shell> pkgadd -d mysql-5.1.59-solaris10-x86_64.pkg shell> mysql_upgrade shell> mysqld_safe & You should check the notes in *Note upgrading-downgrading:: before performing any upgrade.  File: manual.info, Node: solaris-installation-opensolaris, Prev: solaris-installation-pkg, Up: solaris-installation 3.6.2 Installing MySQL on OpenSolaris using IPS ----------------------------------------------- OpenSolaris includes standard packages for MySQL in the core repository. The MySQL packages are based on a specific release of MySQL and updated periodically. For the latest release you must use either the native Solaris `PKG', `tar', or source installations. The native OpenSolaris packages include SMF files so that you can easily control your MySQL installation, including automatic startup and recovery, using the native service management tools. To install MySQL on OpenSolaris, use the `pkg' command. You will need to be logged in as root, or use the `pfexec' tool, as shown in the example below: shell> pfexec pkg install SUNWmysql51 The package set installs three individual packages, `SUNWmysql51lib', which contains the MySQL client libraries; `SUNWmysql51r' which contains the root components, including SMF and configuration files; and `SUNWmysql51u' which contains the scripts, binary tools and other files. You can install these packages individually if you only need the corresponding components. The MySQL files are installed into `/usr/mysql' which symbolic links for the sub directories (`bin', `lib', etc.) to a version specific directory. For MySQL 5.1, the full installation is located in `/usr/mysql/5.1'. The default data directory is `/var/mysql/5.1/data'. The configuration file is installed in `/etc/mysql/5.1/my.cnf'. This layout permits multiple versions of MySQL to be installed, without overwriting the data and binaries from other versions. Once installed, you must run *Note `mysql_install_db': mysql-install-db. to initialize the database, and use the *Note `mysql_secure_installation': mysql-secure-installation. to secure your installation. * Using SMF to manage your MySQL installation * Once installed, you can start and stop your MySQL server using the installed SMF configuration. The service name is `mysql', or if you have multiple versions installed, you should use the full version name, for example `mysql:version_51'. To start and enable MySQL to be started at boot time: shell> svcadm enable mysql To disable MySQL from starting during boot time, and shut the MySQL server down if it is running, use: shell> svcadm disable mysql To restart MySQL, for example after a configuration file changes, use the `restart' option: shell> svcadm restart mysql You can also use SMF to configure the data directory and enable full 64-bit mode. For example, to set the data directory used by MySQL: shell> svccfg svc:> select mysql:version_51 svc:/application/database/mysql:version_51> setprop mysql/data=/data0/mysql By default, the 32-bit binaries are used. To enable the 64-bit server on 64-bit platforms, set the `enable_64bit' parameter. For example: svc:/application/database/mysql:version_51> setprop mysql/enable_64bit=1 You need to refresh the SMF after settings these options: shell> svcadm refresh mysql  File: manual.info, Node: aix-installation, Next: hpux-installation, Prev: solaris-installation, Up: installing 3.7 Installing MySQL on IBM AIX =============================== * Menu: * aix-installation-general:: General Notes on Installing MySQL on AIX MySQL for IBM AIX is available in a number of different forms: * Using a binary tarball distribution provided at `http://dev.mysql.com/downloads/'. Please read the *Note general notes on AIX installation: aix-installation-general. before continuing. For more information on binary installations, see *Note binary-installation::. * Using a source tarball and compiling MySQL. Please read the *Note general notes on AIX installation: aix-installation-general. before continuing. You should also check the instructions on *Note building on AIX from source: aix-installation-source. For general information on building from source, see *Note source-installation::.  File: manual.info, Node: aix-installation-general, Prev: aix-installation, Up: aix-installation 3.7.1 General Notes on Installing MySQL on AIX ---------------------------------------------- General notes on using MySQL on IBM AIX: * If you have problems with threads on AIX 5.3, you should upgrade AIX 5.3 to technology level 7 (5300-07).  File: manual.info, Node: hpux-installation, Next: freebsd-installation, Prev: aix-installation, Up: installing 3.8 Installing MySQL on HP-UX ============================= * Menu: * hpux-installation-general:: General Notes on Installing MySQL on HP-UX * hpux-installation-depot:: Installing MySQL on HP-UX using DEPOT MySQL for HP-UX is available in a number of different forms: * Using a DEPOT distribution provided at `http://dev.mysql.com/downloads/'. Please read the *Note general notes on HP-UX installation: hpux-installation-general. before continuing. For more information on DEPOT installations, see *Note hpux-installation-depot::. * Using a binary tarball distribution provided at `http://dev.mysql.com/downloads/'. Please read the *Note general notes on HP-UX installation: hpux-installation-general. before continuing. For more information on binary installations, see *Note binary-installation::. * Using a source tarball and compiling MySQL. Please read the *Note general notes on HP-UX installation: hpux-installation-general. before continuing. You should also check the instructions on *Note building on HP-UX from source: hpux-installation-source. For general information on building from source, see *Note source-installation::.  File: manual.info, Node: hpux-installation-general, Next: hpux-installation-depot, Prev: hpux-installation, Up: hpux-installation 3.8.1 General Notes on Installing MySQL on HP-UX ------------------------------------------------ Some additional notes on installing and using MySQL on HP-UX: * If you install MySQL using a binary tarball distribution on HP-UX, you may run into trouble even before you get the MySQL distribution unpacked, as the HP-UX `tar' cannot handle long file names. This means that you may see errors when you try to unpack MySQL. If this occurs, you must use GNU `tar' (`gtar') to unpack the distribution. * Because of some critical bugs in the standard HP-UX libraries, you should install the following patches before trying to run MySQL on HP-UX 11.0: PHKL_22840 Streams cumulative PHNE_22397 ARPA cumulative This solves the problem of getting `EWOULDBLOCK' from `recv()' and `EBADF' from `accept()' in threaded applications.  File: manual.info, Node: hpux-installation-depot, Prev: hpux-installation-general, Up: hpux-installation 3.8.2 Installing MySQL on HP-UX using DEPOT ------------------------------------------- The HP-UX DEPOT format packages can be installed using the `swinstall' command. You should install the `ncurses' and `zlib' libraries before installing the MySQL DEPOT package. You can use the free software `depothelper' tool to install these packages and any dependencies for you automatically. To install using the MySQL DEPOT packages, follow this guide: 1. Download the MySQL DEPOT package from `http://dev.mysql.com/downloads/'. You must decompress the package before installation: root-shell> gunzip mysql-5.1.48-hpux11.31-ia64-64bit.depot.gz 2. Install the DEPOT package using `swinstall': root-shell> swinstall -s MYSQL-5.1.49-HPUX11.31-IA64-64BIT.DEPOT MySQL will be installed into a directory matching the depot package name, within `/usr/local'. For convenience, you may want to create a symbolic link to the installed directory, for example: root-shell> ln -s mysql-5.1.49-hpux11.31-ia64-64bit mysql 3. Your package is now installed. You should complete the configuration of MySQL by creating a user and group: root-shell> /usr/sbin/groupadd mysql root-shell> /usr/sbin/useradd -g mysql -d /var/lib/mysql/ -s /bin/false mysql 4. Create the standard database using the new user/group you have created, and set the permissions: root-shell> cd /usr/local/ root-shell> scripts/mysql_install_db --user=mysql root-shell> chown -R root . root-shell> chown -R mysql data 5. Finally, secure your new installation by setting the root passwords, and then start your MySQL server using the `mysql' user: root-shell> mysql_secure_installation root-shell> mysqld_safe --user=mysql &  File: manual.info, Node: freebsd-installation, Next: i5os-installation, Prev: hpux-installation, Up: installing 3.9 Installing MySQL on FreeBSD =============================== This section provides information about installing MySQL on variants of FreeBSD Unix. You can install MySQL on FreeBSD by using the binary distribution provided by Oracle. For more information, see *Note binary-installation::. The easiest (and preferred) way to install MySQL is to use the *Note `mysql-server': mysql-server. and `mysql-client' ports available at `http://www.freebsd.org/'. Using these ports gives you the following benefits: * A working MySQL with all optimizations enabled that are known to work on your version of FreeBSD. * Automatic configuration and build. * Startup scripts installed in `/usr/local/etc/rc.d'. * The ability to use `pkg_info -L' to see which files are installed. * The ability to use `pkg_delete' to remove MySQL if you no longer want it on your machine. The MySQL build process requires GNU make (`gmake') to work. If GNU `make' is not available, you must install it first before compiling MySQL. To install using the ports system: # cd /usr/ports/databases/mysql51-server # make ... # cd /usr/ports/databases/mysql51-client # make ... The standard port installation places the server into `/usr/local/libexec/mysqld', with the startup script for the MySQL server placed in `/usr/local/etc/rc.d/mysql-server'. Some additional notes on the BSD implementation: * To remove MySQL after installation using the ports system: # cd /usr/ports/databases/mysql51-server # make deinstall ... # cd /usr/ports/databases/mysql51-client # make deinstall ... * If you get problems with the current date in MySQL, setting the `TZ' variable should help. See *Note environment-variables::.  File: manual.info, Node: i5os-installation, Next: source-installation, Prev: freebsd-installation, Up: installing 3.10 Installing MySQL on i5/OS ============================== The i5/OS POWER MySQL package was created in cooperation with IBM. MySQL works within the Portable Application Solution Environment (PASE) on the System i series of hardware and will also provide database services for the Zend Core for i5/OS. MySQL for i5/OS is provided both as a `tar' file and as a save file (`.savf') package that can be downloaded and installed directly without any additional installation steps required. To install MySQL using the `tar' file, see *Note binary-installation::. MySQL is only supported on i5/OS V5R4 or later releases. The i5/OS PASE must be installed for MySQL to operate. You must be able to login as a user in `*SECOFR' class. You should the installation notes and tips for i5/OS before starting installation. See i5/OS Installation Notes. *Before Installation:* *Note*: The installation package will use an existing configuration if you have previously installed MySQL (which is identified by looking for the file `/etc/my.cnf'). The values for the data directory (`DATADIR') and owner of the MySQL files (`USRPRF') specified during the installation will be ignored, and the values determined from the `/etc/my.cnf' will be used instead. If you want to change these parameters during a new install, you should temporarily rename `/etc/my.cnf', install MySQL using the new parameters you want to use, and then merge your previous `/etc/my.cnf' configuration settings with the new `/etc/my.cnf' file that is created during installation. * You must have a user profile with PASE with suitable privileges. The user should be within the `*SECOFR' class, such as the `QSECOFR' user ID. You can use the `WRKUSRPRF' command to check your user profile. * For network connections to MySQL, you must have TCP/IP enabled. You should also check the following: * Ensure that a name has defined for the system. Run the Configure TCP/IP (`CFGTCP') command and select option 12 (Change TCP/IP domain information) to display this setting. Make sure that a value is listed in the Host name field. * Make sure that the system has a loopback entry which represents the `localhost' or `127.0.0.1'. * Ensure that the IP address of the IBM i machine is mapped correctly to the host name. To install MySQL on i5/OS, follow these steps: 1. On the System i machine, create a save file that will be used to receive the downloaded installation save file. The file should be located within the General Purpose Library (`QGPL'): CRTSAVF FILE(QGPL/MYSQLINST) TESXT('MySQL Save file') 2. Download the MySQL installation save file in 32-bit (`mysql-5.1.59-i5os-power-32bit.savf') or 64-bit (`mysql-5.1.59-i5os-power-64bit.savf') from MySQL Downloads (http://dev.mysql.com/downloads). 3. You need to FTP the downloaded `.savf' file directly into the `QGPL/MYSQLINST' file on the System i server. You can do this through FTP using the following steps after logging in to the System i machine: ftp> bin ftp> cd qgpl ftp> put mysql-5.1.59-i5os-power.savf mysqlinst 4. Log into the System i server using a user in the `*SECOFR' class, such as the `QSECOFR' user ID. 5. You need to restore the installation library stored in the `.savf' save file: RSTLIB MYSQLINST DEV(*SAVF) SAVF(QGPL/MYSQLINST) MBROPT(*ALL) ALWOBJDIF(*ALL) *Note*: You can ignore the security changes-type message at the bottom of the installation panel. 6. Once you have finished restoring the `MYSQLINST' library, check that all the necessary objects for installation are on the system by using the Display Library (`DSPLIB') command: DSPLIB LIB(MYSQLINST) 7. You need to execute the installation command, `MYSQLINST/INSMYSQL'. You can specify three parameter settings during installation: * `DIR('/QOPENSYS/USR/LOCAL/MYSQL')' sets the installation location for the MySQL files. The directory will be created if it does not already exist. * `DATADIR('/QOPENSYS/USR/LOCAL/MYSQL/DATA')' sets the location of the directory that will be used to store the database files and binary logs. The default setting is `/QOpenSys/usr/local/mysql/data'. Note that if the installer detects an existing installation (due to the existence of `/etc/my.cnf'), then the existing setting will be used instead of the default. * `USRPRF(MYSQL)' sets the user profile that will own the files that are installed. The profile will be created if it does not already exist. *Note*: You should choose an appropriate user for using the MySQL server installation. The user will be used whenever you need to do any administration on the MySQL server. Once you have set the appropriate parameters, you can begin the installation. The installation copies all the necessary files into a directory matching the `DIR' configuration value; sets the ownership on those files, sets up the MySQL environment and creates the MySQL configuration file (in `/etc/my.cnf') completing all the steps in a typical binary installation process automatically. If this is a new installation of MySQL, or if the installer detects that this is a new version (because the `/etc/my.cnf' file does not exist), then the initial core MySQL databases will also be created during installation. Once the installation has been completed, you will get a notice advising you to set the password for the root user. For more information, *Note postinstallation::. 8. Once the installation has completed, you can delete the installation file: DLTLIB LIB(MYSQLINST) *Upgrading an existing MySQL instance* You need to execute the upgrade command, `MYSQLINST/UPGMYSQL'. *Note*: You cannot use `MYSQLINST/UPGMYSQL' to upgrade between major versions of MySQL (for example from 5.0 to 5.1). For information and advice on migrating between major versions you can use the advice provided in *Note upgrading-from-previous-series::. You must specify 6 parameters to perform an upgrade: * `DIR('/QOpenSys/usr/local/')': Sets the installation location for the MySQL files. The directory will be created if it does not already exist. This is the directory that the MySQL server will be installed into, inside a directory with a name matching the version and release. For example, if installing MySQL 5.1.59 with the `DIR' set to `/QOpenSys/usr/local/' would result in `/QOpenSys/usr/local/mysql-5.1.59-i5os-power64' and a symbolic link to this directory will be created in `/QOpenSys/usr/local/mysql'. * `DATADIR('/QOpenSys/mysql/data')': Sets the location of the directory that will be upgraded. * `USRPRF('MYSQL')': Sets the user profile that will own the files that are installed. The profile will be created if it does not already exist; if it is created as part of the upgrade process, it will be disabled initially. You may wish to enable this user profile so that it can be used to start the MySQL server later. It is best practice to use the one previously created during the first installation. * `MYSQLUSR('root user')': Any user account in the current MySQL server with `SUPER' privileges. * `PASSWORD('root user password')': The password for the above account. This is necessary as the upgrade starts the MySQL server to upgrade the tables and the password is need to be able to shutdown the MySQL server. * `CURINST('path to previous install')': The full path to the installation that is being upgraded. For example an installation in `/QOpenSys/usr/local/' will be `/QOpenSys/usr/local/mysql-5.1.59-i5os-power64'. Failure to specify this option may result in corruption of your existing data files. For example: MYSQLINST/UPGMYSQL DIR('/QOPENSYS/USR/LOCAL/') DATADIR('/QOPENSYS/MYSQL/DATA') » USERPRF(MYSQL) MYSQLUSR('ROOT') PASSWORD('ROOT') CURINST('/QOPENSYS/USR/LOCAL/MYSQL-5.1.59-I5OS-POWER64') You should receive a Program Message indicating `UPGRADE SUCCESSFUL!' upon completion or an error message if there is a problem.You can view the upgrade programs progression and the error in the text file `upgrade.log' in the installation directory. *To start MySQL*: 1. Log into the System i server using the user profile create or specified during installation. By default, this is `MYSQL'. *Note*: You should start *Note `mysqld_safe': mysqld-safe. using a user that in the PASE environment has the id=0 (the equivalent of the standard Unix `root' user). If you do not use a user with this ID then the system will be unable to change the user when executing *Note `mysqld': mysqld. as set using `--user' option. If this happens, *Note `mysqld': mysqld. may be unable to read the files located within the MySQL data directory and the execution will fail. 2. Enter the PASE environment using `call qp2term'. 3. Start the MySQL server by changing to the installation directory and running *Note `mysqld_safe': mysqld-safe, specifying the user name used to install the server. The installer conveniently installs a symbolic link to the installation directory (`mysql-5.0.42-i5os-power-32bit') as `/opt/mysql/mysql': > cd /opt/mysql/mysql > bin/mysqld_safe --user=mysql & You should see a message similar to the following: Starting mysqld daemon with databases » from /opt/mysql/mysql-enterprise-5.0.42-i5os-power-32bit/data If you are having problems starting MySQL server, see *Note starting-server::. *To stop MySQL*: 1. Log into the System i server using the user profile create or specified during installation. By default, this is `MYSQL'. 2. Enter the PASE environment using `call qp2term'. 3. Stop the MySQL server by changing into the installation directory and running *Note `mysqladmin': mysqladmin, specifying the user name used to install the server: > cd /opt/mysql/mysql > bin/mysqladmin -u root shutdown If the session that you started and stopped MySQL are the same, you may get the log output from `mysqld': STOPPING server from pid file » /opt/mysql/mysql-enterprise-5.0.42-i5os-power-32bit/data/I5DBX.RCHLAND.IBM.COM.pid 070718 10:34:20 mysqld ended If the sessions used to start and stop MySQL are different, you will not receive any confirmation of the shutdown. _Note and tips_ * A problem has been identified with the installation process on DBCS systems. If you are having problems install MySQL on a DBCS system, you need to change your job's coded character set identifier (`CSSID') to 37 (`EBCDIC') before executing the install command, `INSMYSQL'. To do this, determine your existing `CSSID' (using `DSPJOB' and selecting option 2), execute `CHGJOB CSSID(37)', run `INSMYSQL' to install MySQL and then execute `CHGJOB' again with your original `CSSID.' * If you want to use the Perl scripts that are included with MySQL, you need to download the iSeries Tools for Developers (5799-PTL). See `http://www-03.ibm.com/servers/enable/site/porting/tools/'.  File: manual.info, Node: source-installation, Next: postinstallation, Prev: i5os-installation, Up: installing 3.11 Installing MySQL from Source ================================= * Menu: * source-installation-layout:: MySQL Layout for Source Installation * installing-source-distribution:: Installing MySQL from a Standard Source Distribution * installing-development-tree:: Installing MySQL from a Development Source Tree * source-configuration-options:: MySQL Source-Configuration Options * compilation-problems:: Dealing with Problems Compiling MySQL * compile-and-link-options:: Compiling and Linking an Optimized `mysqld' Server * windows-source-build:: Installing MySQL from Source on Windows * solaris-installation-source:: Notes on Installing MySQL on Solaris from Source * aix-installation-source:: Notes on Installing MySQL on AIX from Source * hpux-installation-source:: Notes on Installing MySQL on HP-UX from Source Building MySQL from the source code enables you to customize build parameters, compiler optimizations, and installation location. For a list of systems on which MySQL is known to run, see *Note supported-os::. Before you proceed with an installation from source, check whether we produce a precompiled binary distribution for your platform and whether it works for you. We put a great deal of effort into ensuring that our binaries are built with the best possible options for optimal performance. Instructions for installing binary distributions are available in *Note binary-installation::. To obtain a source distribution for MySQL, see *Note getting-mysql::. MySQL source distributions are available as compressed `tar' files, Zip archives, or RPM packages. Distribution files have names of the form `mysql-VERSION.tar.gz', `mysql-VERSION.zip', or `mysql-VERSION.rpm', where VERSION is a number like `5.1.59'. To perform a MySQL installation using the source code: * To build MySQL from source on Unix-like systems, including Linux, commercial Unix, BSD, Mac OS X and others using a `.tar.gz' or RPM-based source code distribution, see *Note installing-source-distribution::. * To build MySQL from source on Windows (Windows XP or newer required), see *Note windows-source-build::. * For information on building from one of our development trees, see *Note installing-development-tree::. * For information on using the `configure' command to specify the source build parameters, including links to platform specific parameters that you might need, see *Note source-configuration-options::. To install MySQL from source, your system must have the following tools: * GNU `gunzip' to uncompress the distribution and a reasonable `tar' to unpack it (if you use a `.tar.gz' distribution), or `WinZip' or another tool that can read `.zip' files (if you use a `.zip' distribution). GNU `tar' is known to work. The standard `tar' provided with some operating systems is not able to unpack the long file names in the MySQL distribution. You should download and install GNU `tar', or if available, use a preinstalled version of GNU tar. Usually this is available as `gnutar', `gtar', or as `tar' within a GNU or Free Software directory, such as `/usr/sfw/bin' or `/usr/local/bin'. GNU `tar' is available from `http://www.gnu.org/software/tar/'. * A working ANSI C++ compiler. GCC 3.4.6 or later, Sun Studio 10 or later, Visual Studio 2005 or later, and many current vendor-supplied compilers are known to work. * A good `make' program. Although some platforms come with their own `make' implementations, it is highly recommended that you use GNU `make' 3.75 or newer. It may already be available on your system as `gmake'. GNU `make' is available from `http://www.gnu.org/software/make/'. * `libtool' 1.5, available from `http://www.gnu.org/software/libtool/'. 1.5.24 or later is recommended. If you run into problems and need to file a bug report, please use the instructions in *Note bug-reports::.  File: manual.info, Node: source-installation-layout, Next: installing-source-distribution, Prev: source-installation, Up: source-installation 3.11.1 MySQL Layout for Source Installation ------------------------------------------- By default, when you install MySQL after compiling it from a source distribution, the installation step installs files under `/usr/local'. Components are installed in the directories shown in the following table. To configure particular installation locations, use the options described at *Note source-configuration-options::. *MySQL Layout for Installation from Source* Directory Contents of Directory `bin' Client programs and scripts `include/mysql' Include (header) files `Docs' Manual in Info format `man' Unix manual pages `lib/mysql' Libraries `libexec' The *Note `mysqld': mysqld. server `share/mysql' Miscellaneous support files, including error messages, sample configuration files, SQL for database installation `sql-bench' Benchmarks `var' Log files, databases Within its installation directory, the layout of a source installation differs from that of a binary installation in the following ways: * The *Note `mysqld': mysqld. server is installed in the `libexec' directory rather than in the `bin' directory. * The data directory is `var' rather than `data'. * *Note `mysql_install_db': mysql-install-db. is installed in the `bin' directory rather than in the `scripts' directory. * The header file and library directories are `include/mysql' and `lib/mysql' rather than `include' and `lib'.  File: manual.info, Node: installing-source-distribution, Next: installing-development-tree, Prev: source-installation-layout, Up: source-installation 3.11.2 Installing MySQL from a Standard Source Distribution ----------------------------------------------------------- To install MySQL from source, first configure, build, and install from a source package. Then follow the same postinstallation setup sequence as for a binary installation. If you start from a source RPM, use the following command to make a binary RPM that you can install. If you do not have `rpmbuild', use `rpm' instead. shell> rpmbuild --rebuild --clean MySQL-VERSION.src.rpm The result is one or more binary RPM packages that you install as indicated in *Note linux-installation-rpm::. The sequence for installation from a compressed `tar' file source distribution is similar to the process for installing from a generic binary distribution that is detailed in *Note binary-installation::. For a MySQL `.tar.gz' source distribution, the basic installation command sequence looks like this: # Preconfiguration setup shell> groupadd mysql shell> useradd -g mysql mysql # Beginning of source-build specific instructions shell> tar zxvf mysql-VERSION.tar.gz shell> cd mysql-VERSION shell> ./configure --prefix=/usr/local/mysql shell> make shell> make install # End of source-build specific instructions # Postinstallation setup shell> cd /usr/local/mysql shell> chown -R mysql . shell> chgrp -R mysql . shell> bin/mysql_install_db --user=mysql shell> chown -R root . shell> chown -R mysql var # Next command is optional shell> cp support-files/my-medium.cnf /etc/my.cnf shell> bin/mysqld_safe --user=mysql & # Next command is optional shell> cp support-files/mysql.server /etc/init.d/mysql.server A more detailed version of the source-build specific instructions is shown following. Perform the following steps as the `mysql' user, except as noted. *Note*: The procedure shown here does not set up any passwords for MySQL accounts. After following the procedure, proceed to *Note postinstallation::, for postinstallation setup and testing. 1. Set up the `mysql' user and group that will be used to run and execute the MySQL server and own the database directory. For details, see Creating a `mysql' System User and Group, in *Note binary-installation::. 2. Pick the directory under which you want to unpack the distribution and change location into it. 3. Obtain a distribution file using the instructions in *Note getting-mysql::. 4. Unpack the distribution into the current directory. `tar' can uncompress and unpack the distribution if it has `z' option support: shell> tar zxvf /PATH/TO/MYSQL-VERSION.tar.gz This command creates a directory named `mysql-VERSION'. If your `tar' does not have `z' option support, use `gunzip' to unpack the distribution and `tar' to unpack it: shell> gunzip < /PATH/TO/MYSQL-VERSION.tar.gz | tar xvf - 5. Change location into the top-level directory of the unpacked distribution: shell> cd mysql-VERSION 6. Configure the source directory: shell> ./configure --prefix=/usr/local/mysql When you run `configure', you might want to specify other options. For example, if you need to debug *Note `mysqld': mysqld. or a MySQL client, run `configure' with the `--with-debug' option, and then recompile and link your clients with the new client library. See MySQL Internals: Porting (http://forge.mysql.com/wiki/MySQL_Internals_Porting). Run `./configure --help' for a list of options. *Note source-configuration-options::, discusses some of the more useful options. If `configure' fails and you are going to send mail to a MySQL mailing list to ask for assistance, please include any lines from `config.log' that you think can help solve the problem. Also include the last couple of lines of output from `configure'. To file a bug report, please use the instructions in *Note bug-reports::. 7. Compile the source distribution: shell> make Use `gmake' instead on systems where you are using GNU `make' and it has been installed as `gmake'. If the compile fails, see *Note compilation-problems::, for help. 8. Install the distribution: shell> make install You might need to run this command as `root'. The remainder of the installation process, including setting up the configuration file, creating the core databases, and starting the MySQL server, are identical to the remainder of the process as shown in Generic Binary Install. After everything has been installed, test the distribution. To start the MySQL server, use the following command: shell> /usr/local/mysql/bin/mysqld_safe --user=mysql & If you run the command as `root', you should use the `--user' option as shown. The option value is the name of the login account that you created in the first step to use for running the server. If you run the *Note `mysqld_safe': mysqld-safe. command while logged in as that user, you can omit the `--user' option. If the command fails immediately and prints `mysqld ended', look for information in the error log (which by default is the `HOST_NAME.err' file in the data directory). For more information about *Note `mysqld_safe': mysqld-safe, see *Note mysqld-safe::. To make it more convenient to invoke programs installed in `/usr/local/mysql/bin', you can add that directory to your `PATH' environment variable setting. That enables you to run a program by typing only its name, not its entire path name. See *Note setting-environment-variables::. *Note*: The accounts that are listed in the MySQL grant tables initially have no passwords. After starting the server, you should set up passwords for them using the instructions in *Note postinstallation::.  File: manual.info, Node: installing-development-tree, Next: source-configuration-options, Prev: installing-source-distribution, Up: source-installation 3.11.3 Installing MySQL from a Development Source Tree ------------------------------------------------------ This section discusses how to install MySQL from the latest development source code. Development trees have not necessarily received the same level of testing as standard release distributions, so this installation method is usually required only if you need the most recent code changes. Do not use a development tree for production systems. If your goal is simply to get MySQL up and running on your system, you should use a standard release distribution (either a binary or source distribution). See *Note getting-mysql::. To obtain the source tree, you must have Bazaar installed. The Bazaar VCS Web site (http://bazaar-vcs.org) has instructions for downloading and installing Bazaar on different platforms. Bazaar is supported on any platform that supports Python, and is therefore compatible with any Linux, Unix, Windows, or Mac OS X host. MySQL development projects are hosted on Launchpad (http://launchpad.net/). MySQL projects, including MySQL Server, MySQL Workbench, and others are available from the Oracle/MySQL Engineering (http://launchpad.net/~mysql) page. For the repositories related only to MySQL Server, see the MySQL Server (http://launchpad.net/mysql-server) page. For information about using Bazaar with MySQL, see `http://forge.mysql.com/wiki/MySQL_Bazaar_Howto'. To build under Unix/Linux, you must have the following tools installed: * A good `make' program. Although some platforms come with their own `make' implementations, it is highly recommended that you use GNU `make' 3.75 or newer. It may already be available on your system as `gmake'. GNU `make' is available from `http://www.gnu.org/software/make/'. * `autoconf' 2.58 (or newer), available from `http://www.gnu.org/software/autoconf/'. * `automake' 1.8.1, available from `http://www.gnu.org/software/automake/'. * `libtool' 1.5, available from `http://www.gnu.org/software/libtool/'. 1.5.24 or later is recommended. * `m4', available from `http://www.gnu.org/software/m4/'. * `bison', available from `http://www.gnu.org/software/bison/'. You should use the latest version of `bison' where possible. Versions 1.75 and 2.1 are known to work. There have been reported problems with `bison' 1.875. If you experience problems, upgrade to a later, rather than earlier, version. To build under Windows you must have Microsoft Visual C++ 2005 Express Edition, Visual Studio .Net 2003 (7.1), or Visual Studio 2005 (8.0) compiler system. Once the necessary tools are installed, create a local branch of the MySQL development tree on your machine using this procedure: 1. To obtain a copy of the MySQL source code, you must create a new Bazaar branch. If you do not already have a Bazaar repository directory set up, you must initialize a new directory: shell> mkdir mysql-server shell> bzr init-repo --trees mysql-server This is a one-time operation. 2. Assuming that you have an initialized repository directory, you can branch from the public MySQL server repositories to create a local source tree. To create a branch of a specific version: shell> cd mysql-server shell> bzr branch lp:mysql-server/5.1 mysql-5.1 This is a one-time operation per source tree. You can branch the source trees for several versions of MySQL under the `mysql-server' directory. 3. The initial download will take some time to complete, depending on the speed of your connection. Please be patient. Once you have downloaded the first tree, additional trees should take significantly less time to download. 4. When building from the Bazaar branch, you may want to create a copy of your active branch so that you can make configuration and other changes without affecting the original branch contents. You can achieve this by branching from the original branch: shell> bzr branch mysql-5.1 mysql-5.1-build 5. To obtain changes made after you have set up the branch initially, update it using the `pull' option periodically. Use this command in the top-level directory of the local copy: shell> bzr pull To examine the changeset comments for the tree, use the `log' option to `bzr': shell> bzr log You can also browse changesets, comments, and source code online at the Launchpad MySQL Server (http://launchpad.net/mysql-server) page. If you see diffs (changes) or code that you have a question about, do not hesitate to send email to the MySQL `internals' mailing list. See *Note mailing-lists::. If you think you have a better idea on how to do something, send an email message to the list with a patch. After you have the local branch, you can build MySQL server from the source code. On Windows, the build process is different from Unix/Linux: see *Note windows-source-build::. On Unix/Linux, use the `autoconf' system to create the `configure' script so that you can configure the build environment before building. The following example shows the typical commands required to build MySQL from a source tree. 1. Change location to the top-level directory of the source tree; replace `mysql-5.1' with the appropriate directory name. shell> cd mysql-5.1 2. Prepare the source tree for configuration. Prior to MySQL 5.1.12, you must separately configure the `InnoDB' storage engine. Run the following command from the main source directory: shell> (cd storage/innobase; autoreconf --force --install) You can omit the previous command for MySQL 5.1.12 and later, or if you do not require `InnoDB' support. Prepare the remainder of the source tree: shell> autoreconf --force --install As an alternative to the preceding `autoreconf' command, you can use `BUILD/autorun.sh', which acts as a shortcut for the following sequence of commands: shell> aclocal; autoheader shell> libtoolize --automake --force shell> automake --force --add-missing; autoconf If you get some strange errors during this stage, verify that you have the correct version of `libtool' installed. 3. Configure the source tree and compile MySQL: shell> ./configure # Add your favorite options here shell> make For a description of some `configure' options, see *Note source-configuration-options::. A collection of configuration scripts is located in the `BUILD/' subdirectory. For example, you may find it more convenient to use the `BUILD/compile-pentium-debug' script than the preceding set of shell commands. To compile on a different architecture, modify the script by removing flags that are Pentium-specific, or use another script that may be more appropriate. These scripts are provided on an `as-is' basis. They are not supported and their contents may change from release to release. 4. When the build is done, run `make install'. Be careful with this on a production machine; the installation command may overwrite your live release installation. If you already have MySQL installed and do not want to overwrite it, run `./configure' with values for the `--prefix', `--with-tcp-port', and `--with-unix-socket-path' options different from those used by your production server. For additional information about preventing multiple servers from interfering with each other, see *Note multiple-servers::. 5. Play hard with your new installation. For example, try to make new features crash. Start by running `make test'. See *Note mysql-test-suite::. 6. If you have gotten to the `make' stage, but the distribution does not compile, please enter the problem into our bugs database using the instructions given in *Note bug-reports::. If you have installed the latest versions of the required tools, and they crash trying to process our configuration files, please report that also. However, if you get a `command not found' error or a similar problem for required tools, do not report it. Instead, make sure that all the required tools are installed and that your `PATH' variable is set correctly so that your shell can find them.  File: manual.info, Node: source-configuration-options, Next: compilation-problems, Prev: installing-development-tree, Up: source-installation 3.11.4 MySQL Source-Configuration Options ----------------------------------------- The `configure' script provides a great deal of control over how you configure a MySQL source distribution. Typically, you do this using options on the `configure' command line. For a full list of options supported by `configure', run this command: shell> ./configure --help You can also affect `configure' using certain environment variables. See *Note environment-variables::. The following table shows the available `configure' options. *MySQL Source-Configuration Option Reference (`configure')* Formats Description Default IntroducedRemoved `--bindir=DIR' User executables `EPREFIX/bin' `--build=BUILD' Configure for `guessed' building on BUILD `--cache-file=FILE' Cache test results in `disabled' FILE `-C' Alias for `' `-cache-file=config.cache' `--config-cache' `--datadir=DIR' Read-only `PREFIX/share' architecture-independent data `--disable-FEATURE' Do not include FEATURE `' `--disable-community-features'Disable additional `' 5.1.28 features provided by the community `--disable-dependency-tracking'Disable dependency `' tracking `--disable-grant-options'Disable GRANT options `' `--disable-largefile' Omit support for `' large files `--disable-libtool-lock'Disable libtool lock `' `--disable-thread-safe-client'Compile the client `' 5.1.7 without threads `--enable-FEATURE' Enable FEATURE `' `--enable-assembler' Use assembler `' versions of some string functions if available `--enable-debug-sync' Compile in Debug Sync `' 5.1.41 facility `--enable-dependency-tracking'Do not reject slow `' dependency extractors `--enable-fast-install'Optimize for fast `yes' installation `--enable-local-infile'Enable LOCAL for LOAD `disabled' DATA INFILE `--enable-profiling' Build a version with `' 5.1.24 query profiling code `--enable-shared' Build shared libraries `yes' `--enable-static' Build static libraries `yes' `--enable-thread-safe-client'Compile the client `' 5.1.6 with threads `--exec-prefix=EPREFIX'Install `' architecture-dependent files in EPREFIX `-h' Display this help and `' exit `--help' `--help=short' Display options specific to this package `--help=recursive' Display the short help of all the included packages `--host=HOST' Cross-compile to `' build programs to run on HOST `--includedir=DIR' C header files `PREFIX/include' `--infodir=DIR' Info documentation `PREFIX/info' `--libdir=DIR' Object code libraries `EPREFIX/lib' `--libexecdir=DIR' Program executables `EPREFIX/libexec' `--localstatedir=DIR' Modifiable `PREFIX/var' single-machine data `--mandir=DIR' man documentation `PREFIX/man' `-n' Do not create output `' files `--no-create' `--oldincludedir=DIR' C header files for `/usr/include' non-gcc `--prefix=PREFIX' Install `' architecture-independent files in PREFIX `--program-prefix=PREFIX'Prepend PREFIX to `' installed program names `--program-suffix=SUFFIX'Append SUFFIX to `' installed program names `--program-transform-name=PROGRAM'run sed PROGRAM on `' installed program names `-q' Do not print `' `checking...' messages `--quiet' `--sbindir=DIR' System administrative `EPREFIX/sbin' executables `--sharedstatedir=DIR' Modifiable `PREFIX/com' architecture-independent data `--srcdir=DIR' Find the sources in `configure DIR directory or ..' `--sysconfdir=DIR' Read-only `PREFIX/etc' single-machine data `--target=TARGET' Configure for `' building compilers for TARGET `-V' Display version `' information and exit `--version' `--with-PACKAGE' Use PACKAGE `' `--with-archive-storage-engine'Enable the Archive `no' 5.1.9 Storage Engine `--with-atomic-ops' Implement atomic `' 5.1.12 operations using pthread rwlocks or atomic CPU instructions for multi-processor `--with-berkeley-db' Use BerkeleyDB `no' 5.1.11 located in DIR `--with-berkeley-db-includes'Find Berkeley DB `' 5.1.11 headers in DIR `--with-berkeley-db-libs'Find Berkeley DB `' 5.1.11 libraries in DIR `--with-big-tables' Support tables with `' more than 4 G rows even on 32 bit platforms `--with-blackhole-storage-engine'Enable the Blackhole `no' 5.1.9 Storage Engine `--with-charset' Default character set `' `--with-client-ldflags'Extra linking `' arguments for clients `--with-collation' Default collation `' `--with-comment' Comment about `' compilation environment `--with-csv-storage-engine'Enable the CSV `yes' 5.1.9 Storage Engine `--with-darwin-mwcc' Use Metrowerks `' CodeWarrior wrappers on OS X/Darwin `--with-debug' Add debug code `' 5.1.7 `--with-debug=full' Add debug code (adds memory checker, very slow) `--with-embedded-privilege-control'Build parts to check `' user's privileges (only affects embedded library) `--with-embedded-server'Build the embedded `' server `--with-error-inject' Enable error `' 5.1.11 injection in MySQL Server `--with-example-storage-engine'Enable the Example `no' 5.1.9 Storage Engine `--with-extra-charsets'Use charsets in `' addition to default `--with-fast-mutexes' Compile with fast `enabled' 5.1.5 mutexes `--with-federated-storage-engine'Enable federated `no' 5.1.3 5.1.9 storage engine `--with-gnu-ld' Assume the C compiler `no' uses GNU ld `--with-innodb' Enable innobase `no' 5.1.3 5.1.9 storage engine `--with-lib-ccflags' Extra CC options for `' libraries `--with-libwrap=DIR' Compile in libwrap `' (tcp_wrappers) support `--with-low-memory' Try to use less `' memory to compile to avoid memory limitations `--with-machine-type' Set the machine type, `' like "powerpc" `--with-max-indexes=N' Sets the maximum `64' number of indexes per table `--with-mysqld-ldflags'Extra linking `' arguments for mysqld `--with-mysqld-libs' Extra libraries to `' link with for mysqld `--with-mysqld-user' What user the mysqld `' daemon shall be run as `--with-mysqlmanager' Build the `Build if mysqlmanager binary server is built' `--with-named-curses-libs'Use specified curses `' libraries `--with-named-thread-libs'Use specified thread `' libraries `--with-ndb-ccflags' Extra CC options for `' ndb compile `--with-ndb-docs' Include the NDB `' Cluster ndbapi and mgmapi documentation `--with-ndb-port' Port for NDB Cluster `' management server `--with-ndb-port-base' Port for NDB Cluster `' management server `--with-ndb-sci=DIR' Provide MySQL with a `' custom location of sci library `--with-ndb-test' Include the NDB `' Cluster ndbapi test programs `--with-ndbcluster' Include the NDB `no' 5.1.9 Cluster table handler `--with-openssl=DIR' Include the OpenSSL `' 5.1.9 support `--with-openssl-includes'Find OpenSSL headers `' 5.1.9 in DIR `--with-openssl-libs' Find OpenSSL `' 5.1.9 libraries in DIR `--with-other-libc=DIR'Link against libc and `' other standard libraries installed in the specified nonstandard location `--with-pic' Try to use only `Use both' PIC/non-PIC objects `--with-plugin-PLUGIN' Forces the named `' 5.1.11 plugin to be linked into mysqld statically `--with-plugins' Plugins to include in `none' 5.1.11 mysqld `--with-pstack' Use the pstack `' 5.1.54 backtrace library `--with-pthread' Force use of pthread `' library `--with-row-based-replication'Include row-based `' 5.1.5 5.1.6 replication `--with-server-suffix' Append value to the `' version string `--with-ssl=DIR' Include SSL support `' 5.1.11 `--with-system-type' Set the system type, `' like "sun-solaris10" `--with-tags' Include additional `automatic' configurations `--with-tcp-port' Which port to use for `3306' MySQL services `--with-unix-socket-path'Where to put the `' unix-domain socket `--with-yassl' Include the yaSSL `' 5.1.9 support `--with-zlib-dir=no|bundled|DIR'Provide MySQL with a `' custom location of compression library `--without-PACKAGE' Do not use PACKAGE `' `--without-bench' Skip building of the `' 5.1.11 benchmark suite `--without-debug' Build a production `' 5.1.6 version without debugging code `--without-docs' Skip building of the `' documentation `--without-extra-tools'Skip building `' 5.1.9 utilities in the tools directory `--without-geometry' Do not build `' geometry-related parts `--without-libedit' Use system libedit `' instead of bundled copy `--without-man' Skip building of the `' man pages `--without-ndb-binlog' Disable ndb binlog `' 5.1.6 `--without-ndb-debug' Disable special ndb `' debug features `--without-plugin-PLUGIN'Exclude PLUGIN `' 5.1.11 `--without-query-cache'Do not build query `' cache `--without-readline' Use system readline `' instead of bundled copy `--without-row-based-replication'Don't include `' 5.1.7 5.1.14 row-based replication `--without-server' Only build the client `' `--without-uca' Skip building of the `' national Unicode collations If you are using a version of `gcc' recent enough to understand the `-fno-exceptions' option, it is _very important_ that you use this option. Otherwise, you may compile a binary that crashes randomly. Also use `-felide-constructors' and `-fno-rtti' along with `-fno-exceptions'. When in doubt, do the following: CFLAGS="-O3" CXX=gcc CXXFLAGS="-O3 -felide-constructors \ -fno-exceptions -fno-rtti" ./configure \ --prefix=/usr/local/mysql --enable-assembler \ --with-mysqld-ldflags=-all-static On most systems, this gives you a fast and stable binary. When compiling from source, you should also be aware of any platform specific considerations that may influence and impact the build process. Knowing and applying this information will help to ensure you get the best performance and most stable binary for your chosen platform. For more information, use the following sections: * *Note aix-installation-source:: * *Note hpux-installation-source:: * *Note solaris-installation-source:: Some of the `configure' options available are described here. For options that may be of use if you have difficulties building MySQL, see *Note compilation-problems::. Many options configure compile-time defaults that can be overridden at server startup. For example, the `--prefix', `--with-tcp-port', and `with-unix-socket-path' options that configure the default installation base directory location, TCP/IP port number, and Unix socket file can be changed at server startup with the `--basedir', `--port', and `--socket' options for *Note `mysqld': mysqld. * To compile just the MySQL client libraries and client programs and not the server, use the `--without-server' option: shell> ./configure --without-server If you have no C++ compiler, some client programs such as *Note `mysql': mysql. cannot be compiled because they require C++. In this case, you can remove the code in `configure' that tests for the C++ compiler and then run `./configure' with the `--without-server' option. The compile step should still try to build all clients, but you can ignore any warnings about files such as `mysql.cc'. (If `make' stops, try `make -k' to tell it to continue with the rest of the build even if errors occur.) * To build the embedded MySQL library (`libmysqld.a'), use the `--with-embedded-server' option. * To place your log files and database directories elsewhere than under `/usr/local/var', use a `configure' command something like one of these: shell> ./configure --prefix=/usr/local/mysql shell> ./configure --prefix=/usr/local \ --localstatedir=/usr/local/mysql/data The first command changes the installation prefix so that everything is installed under `/usr/local/mysql' rather than the default of `/usr/local'. The second command preserves the default installation prefix, but overrides the default location for database directories (normally `/usr/local/var') and changes it to `/usr/local/mysql/data'. You can also specify the installation directory and data directory locations at server startup time by using the `--basedir' and `--datadir' options. These can be given on the command line or in an MySQL option file, although it is more common to use an option file. See *Note option-files::. * The `--with-tcp-port' option specifies the port number on which the server listens for TCP/IP connections. The default is port 3306. To listen on a different port, use a `configure' command like this: shell> ./configure --with-tcp-port=3307 * On Unix, if you want the MySQL socket file location to be somewhere other than the default location (normally in the directory `/tmp' or `/var/run'), use a `configure' command like this: shell> ./configure \ --with-unix-socket-path=/usr/local/mysql/tmp/mysql.sock The socket file name must be an absolute path name. You can also change the location of `mysql.sock' at server startup by using a MySQL option file. See *Note problems-with-mysql-sock::. * To compile statically linked programs (for example, to make a binary distribution, to get better performance, or to work around problems with some Red Hat Linux distributions), run `configure' like this: shell> ./configure --with-client-ldflags=-all-static \ --with-mysqld-ldflags=-all-static * If you are using `gcc' and do not have `libg++' or `libstdc++' installed, you can tell `configure' to use `gcc' as your C++ compiler: shell> CC=gcc CXX=gcc ./configure When you use `gcc' as your C++ compiler, it does not attempt to link in `libg++' or `libstdc++'. This may be a good thing to do even if you have those libraries installed. Some versions of them have caused strange problems for MySQL users in the past. In most cases, you can get a reasonably optimized MySQL binary by using the following options on the `configure' line: --prefix=/usr/local/mysql --enable-assembler \ --with-mysqld-ldflags=-all-static The full `configure' line would, in other words, be something like the following for all recent `gcc' versions: CFLAGS="-O3 -mpentiumpro" CXX=gcc CXXFLAGS="-O3 -mpentiumpro \ -felide-constructors -fno-exceptions -fno-rtti" ./configure \ --prefix=/usr/local/mysql --enable-assembler \ --with-mysqld-ldflags=-all-static The binaries we provide on the MySQL Web site at `http://dev.mysql.com/downloads/' are all compiled with full optimization and should work well for most users. See *Note binary-installation::. * If the build fails and produces errors about your compiler or linker not being able to create the shared library `libmysqlclient.so.N' (where N is a version number), you can work around this problem by giving the `--disable-shared' option to `configure'. In this case, `configure' does not build a shared `libmysqlclient.so.N' library. * By default, MySQL uses the `latin1' (cp1252 West European) character set. To change the default set, use the `--with-charset' option: shell> ./configure --with-charset=CHARSET CHARSET may be one of `binary', `armscii8', `ascii', `big5', `cp1250', `cp1251', `cp1256', `cp1257', `cp850', `cp852', `cp866', `cp932', `dec8', `eucjpms', `euckr', `gb2312', `gbk', `geostd8', `greek', `hebrew', `hp8', `keybcs2', `koi8r', `koi8u', `latin1', `latin2', `latin5', `latin7', `macce', `macroman', `sjis', `swe7', `tis620', `ucs2', `ujis', `utf8'. (Additional character sets might be available. Check the output from `./configure --help' for the current list.) The default collation may also be specified. MySQL uses the `latin1_swedish_ci' collation by default. To change this, use the `--with-collation' option: shell> ./configure --with-collation=COLLATION To change both the character set and the collation, use both the `--with-charset' and `--with-collation' options. The collation must be a legal collation for the character set. (Use the *Note `SHOW COLLATION': show-collation. statement to determine which collations are available for each character set.) With the `configure' option `--with-extra-charsets=LIST', you can define which additional character sets should be compiled into the server. LIST is one of the following: * A list of character set names separated by spaces * `complex' to include all character sets that can't be dynamically loaded * `all' to include all character sets into the binaries Clients that want to convert characters between the server and the client should use the `SET NAMES' statement. See *Note charset-connection::. * To configure MySQL with debugging code, use the `--with-debug' option: shell> ./configure --with-debug This causes a safe memory allocator to be included that can find some errors and that provides output about what is happening. See MySQL Internals: Porting (http://forge.mysql.com/wiki/MySQL_Internals_Porting). As of MySQL 5.1.12, using `--with-debug' to configure MySQL with debugging support enables you to use the `--debug="d,parser_debug"' option when you start the server. This causes the Bison parser that is used to process SQL statements to dump a parser trace to the server's standard error output. Typically, this output is written to the error log. * To cause the Debug Sync facility to be compiled into the server, use the `--enable-debug-sync' option. This facility is used for testing and debugging. When compiled in, Debug Sync is disabled by default at runtime. To enable it, start *Note `mysqld': mysqld. with the `--debug-sync-timeout=N' option, where N is a timeout value greater than 0. (The default value is 0, which disables Debug Sync.) N becomes the default timeout for individual synchronization points. Debug Sync is also compiled in if you configure with the `--with-debug' option (which implies `--enable-debug-sync'), unless you also use the `--disable-debug-sync' option. For a description of the Debug Sync facility and how to use synchronization points, see MySQL Internals: Test Synchronization (http://forge.mysql.com/wiki/MySQL_Internals_Test_Synchronization). The `--enable-debug-sync' and `--disable-debug-sync' options were added in MySQL 5.1.41. * If your client programs are using threads, you must compile a thread-safe version of the MySQL client library with the `--enable-thread-safe-client' configure option. This creates a `libmysqlclient_r' library with which you should link your threaded applications. See *Note threaded-clients::. * Some features require that the server be built with compression library support, such as the `COMPRESS()' and `UNCOMPRESS()' functions, and compression of the client/server protocol. The `--with-zlib-dir=no|bundled|DIR' option provides control over compression library support. The value `no' explicitly disables compression support. `bundled' causes the `zlib' library bundled in the MySQL sources to be used. A DIR path name specifies the directory in which to find the compression library sources. * It is possible to build MySQL with large table support using the `--with-big-tables' option. This option causes the variables that store table row counts to be declared as `unsigned long long' rather than `unsigned long'. This enables tables to hold up to approximately 1.844E+19 ((2^32)^2) rows rather than 2^32 (~4.295E+09) rows. Previously it was necessary to pass `-DBIG_TABLES' to the compiler manually in order to enable this feature. * Run `configure' with the `--disable-grant-options' option to cause the `--bootstrap', `--skip-grant-tables', and `--init-file' options for *Note `mysqld': mysqld. to be disabled. For Windows, the `configure.js' script recognizes the `DISABLE_GRANT_OPTIONS' flag, which has the same effect. The capability is available as of MySQL 5.1.15. * This option allows MySQL Community Server features to be enabled. Additional options may be required for individual features, such as `--enable-profiling' to enable statement profiling. This option was added in MySQL 5.1.24. It is enabled by default as of MySQL 5.1.28; to disable it, use `--disable-community-features'. * When given with `--enable-community-features', the `--enable-profiling' option enables the statement profiling capability exposed by the *Note `SHOW PROFILE': show-profile. and *Note `SHOW PROFILES': show-profiles. statements. (See *Note show-profiles::.) This option was added in MySQL 5.1.24. It is enabled by default as of MySQL 5.1.28; to disable it, use `--disable-profiling'. * See *Note general-installation-issues::, for options that pertain to particular operating systems. * See *Note secure-using-ssl::, for options that pertain to configuring MySQL to support secure (encrypted) connections. * Several `configure' options apply to plugin selection and building: --with-plugins=PLUGIN[,PLUGIN]... --with-plugins=GROUP --with-plugin-PLUGIN --without-plugin-PLUGIN PLUGIN is an individual plugin name such as `csv' or `archive'. As shorthand, GROUP is a configuration group name such as `none' (select no plugins) or `all' (select all plugins). You can build a plugin as static (compiled into the server) or dynamic (built as a dynamic library that must be installed using the *Note `INSTALL PLUGIN': install-plugin. statement or the `--plugin-load' option before it can be used). Some plugins might not support static or dynamic build. `configure --help' shows the following information pertaining to plugins: * The plugin-related options * The names of all available plugins * For each plugin, a description of its purpose, which build types it supports (static or dynamic), and which plugin groups it is a part of. `--with-plugins' can take a list of one or more plugin names separated by commas, or a plugin group name. The named plugins are configured to be built as static plugins. `--with-plugin-PLUGIN' configures the given plugin to be built as a static plugin. `--without-plugin-PLUGIN' disables the given plugin from being built. If a plugin is named both with a `--with' and `--without' option, the result is undefined. For any plugin that is not explicitly selected or disabled, it is selected to be built dynamically if it supports dynamic build, and not built if it does not support dynamic build. (Thus, in the case that no plugin options are given, all plugins that support dynamic build are selected to be built as dynamic plugins. Plugins that do not support dynamic build are not built.)  File: manual.info, Node: compilation-problems, Next: compile-and-link-options, Prev: source-configuration-options, Up: source-installation 3.11.5 Dealing with Problems Compiling MySQL -------------------------------------------- All MySQL programs compile cleanly for us with no warnings on Solaris or Linux using `gcc'. On other systems, warnings may occur due to differences in system include files. For other problems, check the following list. The solution to many problems involves reconfiguring. If you do need to reconfigure, take note of the following: * If `configure' is run after it has previously been run, it may use information that was gathered during its previous invocation. This information is stored in `config.cache'. When `configure' starts up, it looks for that file and reads its contents if it exists, on the assumption that the information is still correct. That assumption is invalid when you reconfigure. * Each time you run `configure', you must run `make' again to recompile. However, you may want to remove old object files from previous builds first because they were compiled using different configuration options. To prevent old configuration information or object files from being used, run these commands before re-running `configure': shell> rm config.cache shell> make clean Alternatively, you can run `make distclean'. The following list describes some of the problems that have been found to occur most often when compiling MySQL: * If you get errors such as the ones shown here when compiling `sql_yacc.cc', you probably have run out of memory or swap space: Internal compiler error: program cc1plus got fatal signal 11 Out of virtual memory Virtual memory exhausted The problem is that `gcc' requires a huge amount of memory to compile `sql_yacc.cc' with inline functions. Try running `configure' with the `--with-low-memory' option: shell> ./configure --with-low-memory This option causes `-fno-inline' to be added to the compile line if you are using `gcc' and `-O0' if you are using something else. You should try the `--with-low-memory' option even if you have so much memory and swap space that you think you can't possibly have run out. This problem has been observed to occur even on systems with generous hardware configurations, and the `--with-low-memory' option usually fixes it. * By default, `configure' picks `c++' as the compiler name and GNU `c++' links with `-lg++'. If you are using `gcc', that behavior can cause problems during configuration such as this: configure: error: installation or configuration problem: C++ compiler cannot create executables. You might also observe problems during compilation related to `g++', `libg++', or `libstdc++'. One cause of these problems is that you may not have `g++', or you may have `g++' but not `libg++', or `libstdc++'. Take a look at the `config.log' file. It should contain the exact reason why your C++ compiler did not work. To work around these problems, you can use `gcc' as your C++ compiler. Try setting the environment variable `CXX' to `"gcc -O3"'. For example: shell> CXX="gcc -O3" ./configure This works because `gcc' compiles C++ source files as well as `g++' does, but does not link in `libg++' or `libstdc++' by default. Another way to fix these problems is to install `g++', `libg++', and `libstdc++'. However, do not use `libg++' or `libstdc++' with MySQL because this only increases the binary size of *Note `mysqld': mysqld. without providing any benefits. Some versions of these libraries have also caused strange problems for MySQL users in the past. * To define flags to be used by your C or C++ compilers, specify them using the `CFLAGS' and `CXXFLAGS' environment variables. You can also specify the compiler names this way using `CC' and `CXX'. For example: shell> CC=gcc shell> CFLAGS=-O3 shell> CXX=gcc shell> CXXFLAGS=-O3 shell> export CC CFLAGS CXX CXXFLAGS * If you get errors such as those shown here when compiling *Note `mysqld': mysqld, `configure' did not correctly detect the type of the last argument to `accept()', `getsockname()', or `getpeername()': cxx: Error: mysqld.cc, line 645: In this statement, the referenced type of the pointer value ''length'' is ''unsigned long'', which is not compatible with ''int''. new_sock = accept(sock, (struct sockaddr *)&cAddr, &length); To fix this, edit the `config.h' file (which is generated by `configure'). Look for these lines: /* Define as the base type of the last arg to accept */ #define SOCKET_SIZE_TYPE XXX Change `XXX' to `size_t' or `int', depending on your operating system. (You must do this each time you run `configure' because `configure' regenerates `config.h'.) * If your compile fails with errors such as any of the following, you must upgrade your version of `make' to GNU `make': make: Fatal error in reader: Makefile, line 18: Badly formed macro assignment Or: make: file `Makefile' line 18: Must be a separator (: Or: pthread.h: No such file or directory Solaris and FreeBSD are known to have troublesome `make' programs. GNU `make' 3.75 is known to work. * The `sql_yacc.cc' file is generated from `sql_yacc.yy'. Normally, the build process does not need to create `sql_yacc.cc' because MySQL comes with a pregenerated copy. However, if you do need to re-create it, you might encounter this error: "sql_yacc.yy", line XXX fatal: default action causes potential... This is a sign that your version of `yacc' is deficient. You probably need to install `bison' (the GNU version of `yacc') and use that instead. Versions of `bison' older than 1.75 may report this error: sql_yacc.yy:#####: fatal error: maximum table size (32767) exceeded The maximum table size is not actually exceeded; the error is caused by bugs in older versions of `bison'. * On Debian Linux 3.0, you need to install `gawk' instead of the default `mawk'. * If you get a compilation error on Linux (for example, SuSE Linux 8.1 or Red Hat Linux 7.3) similar to the following one, you probably do not have `g++' installed: libmysql.c:1329: warning: passing arg 5 of `gethostbyname_r' from incompatible pointer type libmysql.c:1329: too few arguments to function `gethostbyname_r' libmysql.c:1329: warning: assignment makes pointer from integer without a cast make[2]: *** [libmysql.lo] Error 1 By default, the `configure' script attempts to determine the correct number of arguments by using `g++' (the GNU C++ compiler). This test yields incorrect results if `g++' is not installed. There are two ways to work around this problem: * Make sure that the GNU C++ `g++' is installed. On some Linux distributions, the required package is called `gpp'; on others, it is named `gcc-c++'. * Use `gcc' as your C++ compiler by setting the `CXX' environment variable to `gcc': export CXX="gcc" You must run `configure' again after making either of those changes. For information about acquiring or updating tools, see the system requirements in *Note source-installation::.  File: manual.info, Node: compile-and-link-options, Next: windows-source-build, Prev: compilation-problems, Up: source-installation 3.11.6 Compiling and Linking an Optimized `mysqld' Server --------------------------------------------------------- Most of the following tests were performed on Linux with the MySQL benchmarks, but they should give some indication for other operating systems and workloads. You obtain the fastest executables when you link with `-static'. By using better compiler and compilation options, you can obtain a 10% to 30% speed increase in applications. This is particularly important if you compile the MySQL server yourself. When we tested both the Cygnus CodeFusion and Fujitsu compilers, neither was sufficiently bug-free to enable MySQL to be compiled with optimizations enabled. The standard MySQL binary distributions are compiled with support for all character sets. When you compile MySQL yourself, include support only for the character sets that you are going to use. This is controlled by the `--with-charset' option to `configure'. Here is a list of some measurements that we have made: * If you link dynamically (without `-static'), the result is 13% slower on Linux. Note that you still can use a dynamically linked MySQL library for your client applications. It is the server that is most critical for performance. * For a connection from a client to a server running on the same host, if you connect using TCP/IP rather than a Unix socket file, performance is 7.5% slower. (On Unix, if you connect to the host name `localhost', MySQL uses a socket file by default.) * For TCP/IP connections from a client to a server, connecting to a remote server on another host is 8% to 11% slower than connecting to a server on the same host, even for connections faster than 100Mb/s Ethernet. * When running our benchmark tests using secure connections (all data encrypted with internal SSL support) performance was 55% slower than with unencrypted connections. * On a Sun UltraSPARC-IIe, a server compiled with Forte 5.0 is 4% faster than one compiled with `gcc' 3.2. * On a Sun UltraSPARC-IIe, a server compiled with Forte 5.0 is 4% faster in 32-bit mode than in 64-bit mode. * Compiling on Linux-x86 using `gcc' without frame pointers (`-fomit-frame-pointer' or `-fomit-frame-pointer -ffixed-ebp') makes *Note `mysqld': mysqld. 1% to 4% faster.  File: manual.info, Node: windows-source-build, Next: solaris-installation-source, Prev: compile-and-link-options, Up: source-installation 3.11.7 Installing MySQL from Source on Windows ---------------------------------------------- These instructions describe how to build binaries from source for MySQL 5.1 on Windows. Instructions are provided for building binaries from a standard source distribution or from the Bazaar tree that contains the latest development source. *Note*: The instructions here are strictly for users who want to test MySQL on Microsoft Windows from the latest source distribution or from the Bazaar tree. For production use, we do not advise using a MySQL server built by yourself from source. Normally, it is best to use precompiled binary distributions of MySQL that are built specifically for optimal performance on Windows by Oracle Corporation. Instructions for installing binary distributions are available in *Note windows-installation::. To build MySQL on Windows from source, you must satisfy the following system, compiler, and resource requirements: * Windows 2000, Windows XP, or newer version. Windows Vista is supported when using Visual Studio 2005 provided you have installed the following updates: * Microsoft Visual Studio 2005 Professional Edition - ENU Service Pack 1 (KB926601) (http://support.microsoft.com/?kbid=926601) * Security Update for Microsoft Visual Studio 2005 Professional Edition - ENU (KB937061) (http://support.microsoft.com/?kbid=937061) * Update for Microsoft Visual Studio 2005 Professional Edition - ENU (KB932232) (http://support.microsoft.com/?kbid=932232) * `CMake', which can be downloaded from `http://www.cmake.org'. After installing, modify your `PATH' environment variable to include the directory where `cmake' is located. * Microsoft Visual C++ 2005 Express Edition, Visual Studio .Net 2003 (7.1), or Visual Studio 2005 (8.0) compiler system. * If you are using Visual C++ 2005 Express Edition, you must also install an appropriate Platform SDK. More information and links to downloads for various Windows platforms is available from `http://www.microsoft.com/downloads/details.aspx?familyid=0baf2b35-c656-4969-ace8-e4c0c0716adb'. * If you are compiling from a Bazaar tree or making changes to the parser, you need `bison' for Windows, which can be downloaded from `http://gnuwin32.sourceforge.net/packages/bison.htm'. Download the package labeled `Complete package, excluding sources'. After installing the package, modify your `PATH' environment variable to include the directory where `bison' is located. *Note*: On Windows, the default location for `bison' is the `C:\Program Files\GnuWin32' directory. Some utilities, including `m4', may fail to find `bison' because of the space in the directory name. You can resolve this by installing into a directory that does not contain a space; for example `C:\GnuWin32'. * Cygwin might be necessary if you want to run the test script or package the compiled binaries and support files into a Zip archive. (Cygwin is needed only to test or package the distribution, not to build it.) Cygwin is available from `http://cygwin.com'. * 3GB to 5GB of disk space. You also need a MySQL source distribution for Windows, which can be obtained two ways: * Obtain a source distribution packaged by Oracle Corporation. These are available from `http://dev.mysql.com/downloads/'. * Package a source distribution yourself from the latest Bazaar developer source tree. For instructions on pulling the latest source files, see *Note installing-development-tree::. If you find something not working as expected, or you have suggestions about ways to improve the current build process on Windows, please send a message to the `win32' mailing list. See *Note mailing-lists::. *Note*: To compile from the source code on Windows you must use the standard source distribution (for example, `mysql-5.1.59.zip') or `mysql-5.1.59.tar.gz'). You build from the same distribution as used to build MySQL on Unix, Linux and other platforms. Do _not_ use the Windows Source distributions as they do not contain the necessary configuration script and other files. Follow this procedure to build MySQL: 1. If you are installing from a packaged source distribution, create a work directory (for example, `C:\workdir'), and unpack the source distribution there using `WinZip' or another Windows tool that can read `.zip' files. This directory is the work directory in the following instructions. *Note*: Commands that are located in the `win' directory should be executed from the top-level source directory. Do not change location into the `win' directory, as the commands will not execute correctly. 2. Start a command shell. If you have not configured the `PATH' and other environment variables for all command shells, you may be able to start a command shell from the `Start Menu' within the Windows Visual Studio menu that contains the necessary environment changes. 3. Within the command shell, navigate to the work directory and run the following command: C:\workdir>win\configure.js OPTIONS If you have associated the `.js' file extension with an application such as a text editor, then you may need to use the following command to force `configure.js' to be executed as a script: C:\workdir>cscript win\configure.js OPTIONS These options are available for `configure.js': * `WITH_INNOBASE_STORAGE_ENGINE': Enable the *Note `InnoDB': innodb-storage-engine. storage engine. * `WITH_PARTITION_STORAGE_ENGINE': Enable user-defined partitioning. * `WITH_ARCHIVE_STORAGE_ENGINE': Enable the *Note `ARCHIVE': archive-storage-engine. storage engine. * `WITH_BLACKHOLE_STORAGE_ENGINE': Enable the *Note `BLACKHOLE': blackhole-storage-engine. storage engine. * `WITH_EXAMPLE_STORAGE_ENGINE': Enable the *Note `EXAMPLE': example-storage-engine. storage engine. * `WITH_FEDERATED_STORAGE_ENGINE': Enable the *Note `FEDERATED': federated-storage-engine. storage engine. * `WITH_NDBCLUSTER_STORAGE_ENGINE': Enable the *Note `NDBCLUSTER': mysql-cluster. storage engine in the MySQL server; cause binaries for the MySQL Cluster management and data node, management client, and other programs to be built. This option is supported only in MySQL Cluster NDB 7.0 and later (*Note `NDBCLUSTER': mysql-cluster. storage engine versions 6.4.0 and later) using the MySQL Cluster sources. It cannot be used to enable clustering support in other MySQL source trees or distributions. * `MYSQL_SERVER_SUFFIX=SUFFIX': Server suffix, default none. * `COMPILATION_COMMENT=COMMENT': Server comment, default "Source distribution". * `MYSQL_TCP_PORT=PORT': Server port, default 3306. * `DISABLE_GRANT_OPTIONS': Disables the `--bootstrap', `--skip-grant-tables', and `--init-file' options for *Note `mysqld': mysqld. This option is available as of MySQL 5.1.15. For example (type the command on one line): C:\workdir>win\configure.js WITH_INNOBASE_STORAGE_ENGINE WITH_PARTITION_STORAGE_ENGINE MYSQL_SERVER_SUFFIX=-pro 4. From the work directory, execute the `win\build-vs9.bat' (Windows Visual Studio 2008), `win\build-vs8.bat' (Windows Visual Studio 2005), or `win\build-vs71.bat' (Windows Visual Studio 2003) script, depending on the version of Visual Studio you have installed. The script invokes `CMake', which generates the `mysql.sln' solution file. You can also use the corresponding 64-bit file (for example `win\build-vs8_x64.bat' or `win\build-vs9_x64.bat') to build the 64-bit version of MySQL. However, you cannot build the 64-bit version with Visual Studio Express Edition. You must use Visual Studio 2005 (8.0) or higher. 5. From the work directory, open the generated `mysql.sln' file with Visual Studio and select the proper configuration using the `Configuration' menu. The menu provides `Debug', `Release', `RelwithDebInfo', `MinRelInfo' options. Then select `Solution' > `Build' to build the solution. Remember the configuration that you use in this step. It is important later when you run the test script because that script needs to know which configuration you used. 6. Test the server. The server built using the preceding instructions expects that the MySQL base directory and data directory are `C:\mysql' and `C:\mysql\data' by default. If you want to test your server using the source tree root directory and its data directory as the base directory and data directory, you need to tell the server their path names. You can either do this on the command line with the `--basedir' and `--datadir' options, or by placing appropriate options in an option file. (See *Note option-files::.) If you have an existing data directory elsewhere that you want to use, you can specify its path name instead. When the server is running in standalone fashion or as a service based on your configuration, try to connect to it from the *Note `mysql': mysql. interactive command-line utility. You can also run the standard test script, `mysql-test-run.pl'. This script is written in Perl, so you'll need either Cygwin or ActiveState Perl to run it. You may also need to install the modules required by the script. To run the test script, change location into the `mysql-test' directory under the work directory, set the `MTR_VS_CONFIG' environment variable to the configuration you selected earlier (or use the `--vs-config' option), and invoke `mysql-test-run.pl'. For example (using Cygwin and the `bash' shell): shell> `cd mysql-test' shell> `export MTR_VS_CONFIG=debug' shell> `./mysql-test-run.pl --force --timer' shell> `./mysql-test-run.pl --force --timer --ps-protocol' When you are satisfied that the programs you have built are working correctly, stop the server. Now you can install the distribution. One way to do this is to use the *Note `make_win_bin_dist': make-win-bin-dist. script in the `scripts' directory of the MySQL source distribution (see *Note make-win-bin-dist::). This is a shell script, so you must have Cygwin installed if you want to use it. It creates a Zip archive of the built executables and support files that you can unpack in the location at which you want to install MySQL. It is also possible to install MySQL by copying directories and files directly: 1. Create the directories where you want to install MySQL. For example, to install into `C:\mysql', use these commands: C:\> mkdir C:\mysql C:\> mkdir C:\mysql\bin C:\> mkdir C:\mysql\data C:\> mkdir C:\mysql\share C:\> mkdir C:\mysql\scripts If you want to compile other clients and link them to MySQL, you should also create several additional directories: C:\> mkdir C:\mysql\include C:\> mkdir C:\mysql\lib C:\> mkdir C:\mysql\lib\debug C:\> mkdir C:\mysql\lib\opt If you want to benchmark MySQL, create this directory: C:\> mkdir C:\mysql\sql-bench Benchmarking requires Perl support for MySQL. See *Note perl-support::. 2. From the work directory, copy into the `C:\mysql' directory the following files and directories: C:\> cd \workdir C:\workdir> mkdir C:\mysql C:\workdir> mkdir C:\mysql\bin C:\workdir> copy client\Release\*.exe C:\mysql\bin C:\workdir> copy sql\Release\mysqld.exe C:\mysql\bin\mysqld.exe C:\workdir> xcopy scripts\*.* C:\mysql\scripts /E C:\workdir> xcopy share\*.* C:\mysql\share /E If you want to compile other clients and link them to MySQL, you should also copy several libraries and header files: C:\workdir> copy lib\Release\mysqlclient.lib C:\mysql\lib\debug C:\workdir> copy lib\Release\libmysql.* C:\mysql\lib\debug C:\workdir> copy lib\Release\zlib.* C:\mysql\lib\debug C:\workdir> copy lib\Release\mysqlclient.lib C:\mysql\lib\opt C:\workdir> copy lib\Release\libmysql.* C:\mysql\lib\opt C:\workdir> copy lib\Release\zlib.* C:\mysql\lib\opt C:\workdir> copy include\*.h C:\mysql\include C:\workdir> copy libmysql\libmysql.def C:\mysql\include *Note*: If you have compiled a Debug solution, rather than a Release solution, install it by replacing `Release' with `Debug' in the source file names just shown. If you want to benchmark MySQL, you should also do this: C:\workdir> xcopy sql-bench\*.* C:\mysql\bench /E After installation, set up and start the server in the same way as for binary Windows distributions. This includes creating the system tables by running *Note `mysql_install_db': mysql-install-db. For more information, see *Note windows-installation::.  File: manual.info, Node: solaris-installation-source, Next: aix-installation-source, Prev: windows-source-build, Up: source-installation 3.11.8 Notes on Installing MySQL on Solaris from Source ------------------------------------------------------- When building MySQL on Solaris you can use either the Sun Studio or GNU cc compilers. For more information on specific notes and environments, use the following hints. * When building you should ensure that your `PATH' variable includes the necessary tools, including `ar' for building libraries. Some tools are located in `/usr/ccs/bin'. * When running `configure', you should specify the C and C++ compiler explicitly to ensure that the right C compiler combination is used: CC=gcc CXX=g++ ./configure * For detailed information on performance tuning your MySQL installation for Solaris, you can use the information from Krish Shankar (http://blogs.sun.com/krishs/entry/sun_studio_compiler_options_for) and the Sun Solaris MySQL Performance Tuning (http://developers.sun.com/solaris/articles/mysql_perf_tune.html) pages. * If you have an UltraSPARC system, you can get 4% better performance by adding `-mcpu=v8 -Wa,-xarch=v8plusa' to the `CFLAGS' and `CXXFLAGS' environment variables. * If you have Sun's Forte 5.00 (or newer) or Sun Studio compiler, you can run `configure' like this: CC=cc CFLAGS="-Xa -fast -native -xstrconst -mt" \ CXX=CC CXXFLAGS="-noex -mt" \ ./configure --prefix=/usr/local/mysql --enable-assembler * To create a 64-bit SPARC binary with Sun's Forte or Sun Studio compiler, use the following configuration options: CC=cc CFLAGS="-Xa -fast -native -xstrconst -mt -xarch=v9" \ CXX=CC CXXFLAGS="-noex -mt -xarch=v9" ASFLAGS="-xarch=v9" \ ./configure --prefix=/usr/local/mysql --enable-assembler To create a 64-bit Solaris binary using `gcc', add `-m64' to `CFLAGS' and `CXXFLAGS' and remove `--enable-assembler' from the `configure' line. In the MySQL benchmarks, we obtained a 4% speed increase on UltraSPARC when using Forte 5.0 in 32-bit mode, as compared to using `gcc' 3.2 with the `-mcpu' flag. If you create a 64-bit *Note `mysqld': mysqld. binary, it is 4% slower than the 32-bit binary, but can handle more threads and memory. * If you get a problem with `fdatasync' or `sched_yield', you can fix this by adding `LIBS=-lrt' to the `configure' line * Solaris does not provide static versions of all system libraries (`libpthreads' and `libdl'), so you cannot compile MySQL with `--static'. If you try to do so, you get one of the following errors: ld: fatal: library -ldl: not found undefined reference to `dlopen' cannot find -lrt * If you link your own MySQL client programs, you may see the following error at runtime: ld.so.1: fatal: libmysqlclient.so.#: open failed: No such file or directory To avoid this problem, use one of the following methods: * Use the `crle' tool to add the directory containing the `libmysqlclient' library file to the list of standard library directories. You need administrator privileges to do this. Make sure you update the library information, rather than replace it with the new path. For example, the following command adds the directory to the list of standard directories searched for libraries. crle -u -l /usr/local/mysql/lib For 64-bit libraries, add the `-64' option: crle -64 -u -l /usr/local/mysql/lib * Link clients with the `-Wl,r/full/path/to/libmysqlclient.so' flag rather than with `-Lpath'). * Copy `libmysqclient.so' to `/usr/lib'. * Add the path name of the directory where `libmysqlclient.so' is located to the `LD_RUN_PATH' environment variable before running your client. * If you have problems with `configure' trying to link with `-lz' when you do not have `zlib' installed, you have two options: * If you want to be able to use the compressed communication protocol, obtain and install `zlib' from `ftp.gnu.org'. * To build without `zlib', run `configure' with the `--with-named-z-libs=no' option when building MySQL. * If you are using `gcc' and have problems with loading user-defined functions (UDFs) into MySQL, try adding `-lgcc' to the link line for the UDF.  File: manual.info, Node: aix-installation-source, Next: hpux-installation-source, Prev: solaris-installation-source, Up: source-installation 3.11.9 Notes on Installing MySQL on AIX from Source --------------------------------------------------- General notes on building MySQL from source on IBM AIX: * Automatic `xlC' detection is missing from Autoconf, so a number of variables need to be set before running `configure'. The following example uses the IBM compiler: export CC="xlc_r -ma -O3 -qstrict -qoptimize=3 -qmaxmem=8192 " export CXX="xlC_r -ma -O3 -qstrict -qoptimize=3 -qmaxmem=8192" export CFLAGS="-I /usr/local/include" export LDFLAGS="-L /usr/local/lib" export CPPFLAGS=$CFLAGS export CXXFLAGS=$CFLAGS ./configure --prefix=/usr/local \ --localstatedir=/var/mysql \ --sbindir='/usr/local/bin' \ --libexecdir='/usr/local/bin' \ --enable-thread-safe-client \ --enable-large-files The preceding options are used to compile the MySQL distribution that can be found at `http://www-frec.bull.com/'. * If you change the `-O3' to `-O2' in the preceding `configure' line, you must also remove the `-qstrict' option. This is a limitation in the IBM C compiler. * If you compile MySQL with `gcc', you _must_ use the `-fno-exceptions' flag because the exception handling in `gcc' is not thread-safe. There are also some known problems with IBM's assembler that may cause it to generate bad code when used with `gcc'. * If you have problems with signals (MySQL dies unexpectedly under high load), you may have found an OS bug with threads and signals. In this case, you can tell MySQL not to use signals by configuring as follows: CFLAGS=-DDONT_USE_THR_ALARM CXX=gcc \ CXXFLAGS="-felide-constructors -fno-exceptions -fno-rtti \ -DDONT_USE_THR_ALARM" \ ./configure --prefix=/usr/local/mysql --with-debug \ --with-low-memory This does not affect the performance of MySQL, but has the side effect that you cannot kill clients that are `sleeping' on a connection with *Note `mysqladmin kill': mysqladmin. or *Note `mysqladmin shutdown': mysqladmin. Instead, the client dies when it issues its next command. * On some versions of AIX, linking with `libbind.a' makes `getservbyname()' dump core. This is an AIX bug and should be reported to IBM.  File: manual.info, Node: hpux-installation-source, Prev: aix-installation-source, Up: source-installation 3.11.10 Notes on Installing MySQL on HP-UX from Source ------------------------------------------------------ General notes on compiling MySQL on HP-UX. * If you are using HP-UX compiler, you can use the following command (which has been tested with `cc' B.11.11.04): CC=cc CXX=aCC CFLAGS=+DD64 CXXFLAGS=+DD64 ./configure \ --with-extra-character-set=complex You can ignore any errors of the following type: aCC: warning 901: unknown option: `-3': use +help for online documentation * If you get the following error from `configure', verify that you do not have the path to the K&R compiler before the path to the HP-UX C and C++ compiler: checking for cc option to accept ANSI C... no configure: error: MySQL requires an ANSI C compiler (and a C++ compiler). Try gcc. See the Installation chapter in the Reference Manual. * Another reason for compile failure is that you did not define the `+DD64' flags as just described.  File: manual.info, Node: postinstallation, Next: upgrading-downgrading, Prev: source-installation, Up: installing 3.12 Postinstallation Setup and Testing ======================================= * Menu: * unix-postinstallation:: Unix Postinstallation Procedures * default-privileges:: Securing the Initial MySQL Accounts After installing MySQL, there are some issues that you should address. For example, on Unix, you should initialize the data directory and create the MySQL grant tables. On all platforms, an important security concern is that the initial accounts in the grant tables have no passwords. You should assign passwords to prevent unauthorized access to the MySQL server. Optionally, you can create time zone tables to enable recognition of named time zones. The following sections include postinstallation procedures that are specific to Windows systems and to Unix systems. Another section, *Note starting-server::, applies to all platforms; it describes what to do if you have trouble getting the server to start. *Note default-privileges::, also applies to all platforms. You should follow its instructions to make sure that you have properly protected your MySQL accounts by assigning passwords to them. When you are ready to create additional user accounts, you can find information on the MySQL access control system and account management in *Note privilege-system::, and *Note user-account-management::.  File: manual.info, Node: unix-postinstallation, Next: default-privileges, Prev: postinstallation, Up: postinstallation 3.12.1 Unix Postinstallation Procedures --------------------------------------- * Menu: * mysql-install-db-problems:: Problems Running `mysql_install_db' * automatic-start:: Starting and Stopping MySQL Automatically * starting-server:: Starting and Troubleshooting the MySQL Server After installing MySQL on Unix, you must initialize the grant tables, start the server, and make sure that the server works satisfactorily. You may also wish to arrange for the server to be started and stopped automatically when your system starts and stops. You should also assign passwords to the accounts in the grant tables. On Unix, the grant tables are set up by the *Note `mysql_install_db': mysql-install-db. program. For some installation methods, this program is run for you automatically if an existing database cannot be found. * If you install MySQL on Linux using RPM distributions, the server RPM runs *Note `mysql_install_db': mysql-install-db. * Using the native packaging system on many platforms, including Debian Linux, Ubuntu Linux, Gentoo Linux and others, the *Note `mysql_install_db': mysql-install-db. command is run for you. * If you install MySQL on Mac OS X using a PKG distribution, the installer runs *Note `mysql_install_db': mysql-install-db. For other platforms and installation types, including generic binary and source installs, you will need to run *Note `mysql_install_db': mysql-install-db. yourself. The following procedure describes how to initialize the grant tables (if that has not previously been done) and start the server. It also suggests some commands that you can use to test whether the server is accessible and working properly. For information about starting and stopping the server automatically, see *Note automatic-start::. After you complete the procedure and have the server running, you should assign passwords to the accounts created by *Note `mysql_install_db': mysql-install-db. and perhaps restrict access to test databases. For instructions, see *Note default-privileges::. In the examples shown here, the server runs under the user ID of the `mysql' login account. This assumes that such an account exists. Either create the account if it does not exist, or substitute the name of a different existing login account that you plan to use for running the server. For information about creating the account, see Creating a `mysql' System User and Group, in *Note binary-installation::. 1. Change location into the top-level directory of your MySQL installation, represented here by BASEDIR: shell> cd BASEDIR BASEDIR is the installation directory for your MySQL instance. It is likely to be something like `/usr/local/mysql' or `/usr/local'. The following steps assume that you have changed location to this directory. You will find several files and subdirectories in the BASEDIR directory. The most important for installation purposes are the `bin' and `scripts' subdirectories: * The `bin' directory contains client programs and the server. You should add the full path name of this directory to your `PATH' environment variable so that your shell finds the MySQL programs properly. See *Note environment-variables::. For some distribution types, *Note `mysqld': mysqld. is installed in the `libexec' directory. * The `scripts' directory contains the *Note `mysql_install_db': mysql-install-db. script used to initialize the `mysql' database containing the grant tables that store the server access permissions. For some distribution types, *Note `mysql_install_db': mysql-install-db. is installed in the `bin' directory. 2. If necessary, ensure that the distribution contents are accessible to `mysql'. If you installed the distribution as `mysql', no further action is required. If you installed the distribution as `root', its contents will be owned by `root'. Change its ownership to `mysql' by executing the following commands as `root' in the installation directory. The first command changes the owner attribute of the files to the `mysql' user. The second changes the group attribute to the `mysql' group. shell> chown -R mysql . shell> chgrp -R mysql . 3. If necessary, run the *Note `mysql_install_db': mysql-install-db. program to set up the initial MySQL grant tables containing the privileges that determine how users are permitted to connect to the server. You will need to do this if you used a distribution type for which the installation procedure does not run the program for you. Typically, *Note `mysql_install_db': mysql-install-db. needs to be run only the first time you install MySQL, so you can skip this step if you are upgrading an existing installation, However, *Note `mysql_install_db': mysql-install-db. does not overwrite any existing privilege tables, so it should be safe to run in any circumstances. The exact location of *Note `mysql_install_db': mysql-install-db. depends on the layout for your given installation. To initialize the grant tables, use one of the following commands, depending on whether *Note `mysql_install_db': mysql-install-db. is located in the `bin' or `scripts' directory: shell> scripts/mysql_install_db --user=mysql shell> bin/mysql_install_db --user=mysql It might be necessary to specify other options such as `--basedir' or `--datadir' if *Note `mysql_install_db': mysql-install-db. does not identify the correct locations for the installation directory or data directory. For example: shell> scripts/mysql_install_db --user=mysql \ --basedir=/opt/mysql/mysql \ --datadir=/opt/mysql/mysql/data The *Note `mysql_install_db': mysql-install-db. script creates the server's data directory with `mysql' as the owner. Under the data directory, it creates directories for the `mysql' database that holds the grant tables and the `test' database that you can use to test MySQL. The script also creates privilege table entries for `root' and anonymous-user accounts. The accounts have no passwords initially. *Note default-privileges::, describes the initial privileges. Briefly, these privileges permit the MySQL `root' user to do anything, and permit anybody to create or use databases with a name of `test' or starting with `test_'. See *Note privilege-system::, for a complete listing and description of the grant tables. It is important to make sure that the database directories and files are owned by the `mysql' login account so that the server has read and write access to them when you run it later. To ensure this if you run *Note `mysql_install_db': mysql-install-db. as `root', include the `--user' option as shown. Otherwise, you should execute the script while logged in as `mysql', in which case you can omit the `--user' option from the command. If you do not want to have the `test' database, you can remove it after starting the server, using the instructions in *Note default-privileges::. If you have trouble with *Note `mysql_install_db': mysql-install-db. at this point, see *Note mysql-install-db-problems::. 4. Most of the MySQL installation can be owned by `root' if you like. The exception is that the data directory must be owned by `mysql'. To accomplish this, run the following commands as `root' in the installation directory. For some distribution types, the data directory might be named `var' rather than `data'; adjust the second command accordingly. shell> chown -R root . shell> chown -R mysql data 5. If the plugin directory (the directory named by the `plugin_dir' system variable) is writable by the server, it may be possible for a user to write executable code to a file in the directory using *Note `SELECT ... INTO DUMPFILE': select. This can be prevented by making `plugin_dir' read only to the server or by setting `--secure-file-priv' to a directory where *Note `SELECT': select. writes can be made safely. 6. If you installed MySQL using a source distribution, you may want to optionally copy one of the provided configuration files from the `support-files' directory into your `/etc' directory. There are different sample configuration files for different use cases, server types, and CPU and RAM configurations. If you want to use one of these standard files, you should copy it to `/etc/my.cnf', or `/etc/mysql/my.cnf' and edit and check the configuration before starting your MySQL server for the first time. If you do not copy one of the standard configuration files, the MySQL server will be started with the default settings. If you want MySQL to start automatically when you boot your machine, you can copy `support-files/mysql.server' to the location where your system has its startup files. More information can be found in the `mysql.server' script itself, and in *Note automatic-start::. 7. Start the MySQL server: shell> bin/mysqld_safe --user=mysql & It is important that the MySQL server be run using an unprivileged (non-`root') login account. To ensure this if you run *Note `mysqld_safe': mysqld-safe. as `root', include the `--user' option as shown. Otherwise, you should execute the script while logged in as `mysql', in which case you can omit the `--user' option from the command. For further instructions for running MySQL as an unprivileged user, see *Note changing-mysql-user::. If the command fails immediately and prints `mysqld ended', look for information in the error log (which by default is the `HOST_NAME.err' file in the data directory). If you neglected to create the grant tables by running *Note `mysql_install_db': mysql-install-db. before proceeding to this step, the following message appears in the error log file when you start the server: mysqld: Can't find file: 'host.frm' This error also occurs if you run *Note `mysql_install_db': mysql-install-db. as `root' without the `--user' option. Remove the `data' directory and run *Note `mysql_install_db': mysql-install-db. with the `--user' option as described previously. If you have other problems starting the server, see *Note starting-server::. For more information about *Note `mysqld_safe': mysqld-safe, see *Note mysqld-safe::. 8. Use *Note `mysqladmin': mysqladmin. to verify that the server is running. The following commands provide simple tests to check whether the server is up and responding to connections: shell> bin/mysqladmin version shell> bin/mysqladmin variables The output from *Note `mysqladmin version': mysqladmin. varies slightly depending on your platform and version of MySQL, but should be similar to that shown here: shell> bin/mysqladmin version mysqladmin Ver 14.12 Distrib 5.1.59, for pc-linux-gnu on i686 ... Server version 5.1.59 Protocol version 10 Connection Localhost via UNIX socket UNIX socket /var/lib/mysql/mysql.sock Uptime: 14 days 5 hours 5 min 21 sec Threads: 1 Questions: 366 Slow queries: 0 Opens: 0 Flush tables: 1 Open tables: 19 Queries per second avg: 0.000 To see what else you can do with *Note `mysqladmin': mysqladmin, invoke it with the `--help' option. 9. Verify that you can shut down the server: shell> bin/mysqladmin -u root shutdown 10. Verify that you can start the server again. Do this by using *Note `mysqld_safe': mysqld-safe. or by invoking *Note `mysqld': mysqld. directly. For example: shell> bin/mysqld_safe --user=mysql & If *Note `mysqld_safe': mysqld-safe. fails, see *Note starting-server::. 11. Run some simple tests to verify that you can retrieve information from the server. The output should be similar to what is shown here: shell> bin/mysqlshow +--------------------+ | Databases | +--------------------+ | information_schema | | mysql | | test | +--------------------+ shell> bin/mysqlshow mysql Database: mysql +---------------------------+ | Tables | +---------------------------+ | columns_priv | | db | | event | | func | | help_category | | help_keyword | | help_relation | | help_topic | | host | | plugin | | proc | | procs_priv | | servers | | tables_priv | | time_zone | | time_zone_leap_second | | time_zone_name | | time_zone_transition | | time_zone_transition_type | | user | +---------------------------+ shell> bin/mysql -e "SELECT Host,Db,User FROM db" mysql +------+--------+------+ | host | db | user | +------+--------+------+ | % | test | | | % | test_% | | +------+--------+------+ 12. There is a benchmark suite in the `sql-bench' directory (under the MySQL installation directory) that you can use to compare how MySQL performs on different platforms. The benchmark suite is written in Perl. It requires the Perl DBI module that provides a database-independent interface to the various databases, and some other additional Perl modules: DBI DBD::mysql Data::Dumper Data::ShowTable These modules can be obtained from CPAN (`http://www.cpan.org/'). See also *Note perl-installation::. The `sql-bench/Results' directory contains the results from many runs against different databases and platforms. To run all tests, execute these commands: shell> cd sql-bench shell> perl run-all-tests If you do not have the `sql-bench' directory, you probably installed MySQL using RPM files other than the source RPM. (The source RPM includes the `sql-bench' benchmark directory.) In this case, you must first install the benchmark suite before you can use it. There are separate benchmark RPM files named `mysql-bench-VERSION.i386.rpm' that contain benchmark code and data. If you have a source distribution, there are also tests in its `tests' subdirectory that you can run. For example, to run `auto_increment.tst', execute this command from the top-level directory of your source distribution: shell> mysql -vvf test < ./tests/auto_increment.tst The expected result of the test can be found in the `./tests/auto_increment.res' file. 13. At this point, you should have the server running. However, none of the initial MySQL accounts have a password, and the server permits permissive access to test databases. To tighten security, follow the instructions in *Note default-privileges::. The MySQL 5.1 installation procedure creates time zone tables in the `mysql' database but does not populate them. To do so, use the instructions in *Note time-zone-support::. To make it more convenient to invoke programs installed in the `bin' directory under the installation directory, you can add that directory to your `PATH' environment variable setting. That enables you to run a program by typing only its name, not its entire path name. See *Note setting-environment-variables::. You can set up new accounts using the `bin/mysql_setpermission' script if you install the `DBI' and `DBD::mysql' Perl modules. See *Note mysql-setpermission::. For Perl module installation instructions, see *Note perl-support::. If you would like to use *Note `mysqlaccess': mysqlaccess. and have the MySQL distribution in some nonstandard location, you must change the location where *Note `mysqlaccess': mysqlaccess. expects to find the *Note `mysql': mysql. client. Edit the `bin/mysqlaccess' script at approximately line 18. Search for a line that looks like this: $MYSQL = '/usr/local/bin/mysql'; # path to mysql executable Change the path to reflect the location where *Note `mysql': mysql. actually is stored on your system. If you do not do this, a `Broken pipe' error will occur when you run *Note `mysqlaccess': mysqlaccess.  File: manual.info, Node: mysql-install-db-problems, Next: automatic-start, Prev: unix-postinstallation, Up: unix-postinstallation 3.12.1.1 Problems Running `mysql_install_db' ............................................ The purpose of the *Note `mysql_install_db': mysql-install-db. script is to generate new MySQL privilege tables. It does not overwrite existing MySQL privilege tables, and it does not affect any other data. If you want to re-create your privilege tables, first stop the *Note `mysqld': mysqld. server if it is running. Then rename the `mysql' directory under the data directory to save it, and then run *Note `mysql_install_db': mysql-install-db. Suppose that your current directory is the MySQL installation directory and that *Note `mysql_install_db': mysql-install-db. is located in the `bin' directory and the data directory is named `data'. To rename the `mysql' database and re-run *Note `mysql_install_db': mysql-install-db, use these commands. shell> mv data/mysql data/mysql.old shell> scripts/mysql_install_db --user=mysql When you run *Note `mysql_install_db': mysql-install-db, you might encounter the following problems: * **Note `mysql_install_db': mysql-install-db. fails to install the grant tables* You may find that *Note `mysql_install_db': mysql-install-db. fails to install the grant tables and terminates after displaying the following messages: Starting mysqld daemon with databases from XXXXXX mysqld ended In this case, you should examine the error log file very carefully. The log should be located in the directory `XXXXXX' named by the error message and should indicate why *Note `mysqld': mysqld. did not start. If you do not understand what happened, include the log when you post a bug report. See *Note bug-reports::. * *There is a *Note `mysqld': mysqld. process running* This indicates that the server is running, in which case the grant tables have probably been created already. If so, there is no need to run *Note `mysql_install_db': mysql-install-db. at all because it needs to be run only once (when you install MySQL the first time). * *Installing a second *Note `mysqld': mysqld. server does not work when one server is running* This can happen when you have an existing MySQL installation, but want to put a new installation in a different location. For example, you might have a production installation, but you want to create a second installation for testing purposes. Generally the problem that occurs when you try to run a second server is that it tries to use a network interface that is in use by the first server. In this case, you should see one of the following error messages: Can't start server: Bind on TCP/IP port: Address already in use Can't start server: Bind on unix socket... For instructions on setting up multiple servers, see *Note multiple-servers::. * *You do not have write access to the `/tmp' directory* If you do not have write access to create temporary files or a Unix socket file in the default location (the `/tmp' directory) or the `TMP_DIR' environment variable, if it has been set, an error occurs when you run *Note `mysql_install_db': mysql-install-db. or the *Note `mysqld': mysqld. server. You can specify different locations for the temporary directory and Unix socket file by executing these commands prior to starting *Note `mysql_install_db': mysql-install-db. or *Note `mysqld': mysqld, where SOME_TMP_DIR is the full path name to some directory for which you have write permission: shell> TMPDIR=/SOME_TMP_DIR/ shell> MYSQL_UNIX_PORT=/SOME_TMP_DIR/mysql.sock shell> export TMPDIR MYSQL_UNIX_PORT Then you should be able to run *Note `mysql_install_db': mysql-install-db. and start the server with these commands: shell> scripts/mysql_install_db --user=mysql shell> bin/mysqld_safe --user=mysql & If *Note `mysql_install_db': mysql-install-db. is located in the `bin' directory, modify the first command to `bin/mysql_install_db'. See *Note problems-with-mysql-sock::, and *Note environment-variables::. There are some alternatives to running the *Note `mysql_install_db': mysql-install-db. script provided in the MySQL distribution: * If you want the initial privileges to be different from the standard defaults, you can modify *Note `mysql_install_db': mysql-install-db. before you run it. However, it is preferable to use *Note `GRANT': grant. and *Note `REVOKE': revoke. to change the privileges _after_ the grant tables have been set up. In other words, you can run *Note `mysql_install_db': mysql-install-db, and then use `mysql -u root mysql' to connect to the server as the MySQL `root' user so that you can issue the necessary *Note `GRANT': grant. and *Note `REVOKE': revoke. statements. If you want to install MySQL on several machines with the same privileges, you can put the *Note `GRANT': grant. and *Note `REVOKE': revoke. statements in a file and execute the file as a script using `mysql' after running *Note `mysql_install_db': mysql-install-db. For example: shell> scripts/mysql_install_db --user=mysql shell> bin/mysql -u root < your_script_file By doing this, you can avoid having to issue the statements manually on each machine. * It is possible to re-create the grant tables completely after they have previously been created. You might want to do this if you are just learning how to use *Note `GRANT': grant. and *Note `REVOKE': revoke. and have made so many modifications after running *Note `mysql_install_db': mysql-install-db. that you want to wipe out the tables and start over. To re-create the grant tables, remove all the `.frm', `.MYI', and `.MYD' files in the `mysql' database directory. Then run the *Note `mysql_install_db': mysql-install-db. script again. * You can start *Note `mysqld': mysqld. manually using the `--skip-grant-tables' option and add the privilege information yourself using *Note `mysql': mysql.: shell> bin/mysqld_safe --user=mysql --skip-grant-tables & shell> bin/mysql mysql From *Note `mysql': mysql, manually execute the SQL commands contained in *Note `mysql_install_db': mysql-install-db. Make sure that you run *Note `mysqladmin flush-privileges': mysqladmin. or *Note `mysqladmin reload': mysqladmin. afterward to tell the server to reload the grant tables. Note that by not using *Note `mysql_install_db': mysql-install-db, you not only have to populate the grant tables manually, you also have to create them first.  File: manual.info, Node: automatic-start, Next: starting-server, Prev: mysql-install-db-problems, Up: unix-postinstallation 3.12.1.2 Starting and Stopping MySQL Automatically .................................................. Generally, you start the *Note `mysqld': mysqld. server in one of these ways: * Invoke *Note `mysqld': mysqld. directly. This works on any platform. * Run the MySQL server as a Windows service. The service can be set to start the server automatically when Windows starts, or as a manual service that you start on request. For instructions, see *Note windows-start-service::. * Invoke *Note `mysqld_safe': mysqld-safe, which tries to determine the proper options for *Note `mysqld': mysqld. and then runs it with those options. This script is used on Unix and Unix-like systems. See *Note mysqld-safe::. * Invoke *Note `mysql.server': mysql-server. This script is used primarily at system startup and shutdown on systems that use System V-style run directories (that is, `/etc/init.d' and run-level specific directories), where it usually is installed under the name `mysql'. The *Note `mysql.server': mysql-server. script starts the server by invoking *Note `mysqld_safe': mysqld-safe. See *Note mysql-server::. * On Mac OS X, install a separate MySQL Startup Item package to enable the automatic startup of MySQL on system startup. The Startup Item starts the server by invoking *Note `mysql.server': mysql-server. See *Note macosx-installation-startupitem::, for details. A MySQL Preference Pane also provides control for starting and stopping MySQL through the System Preferences, see *Note macosx-installation-prefpane::. * Use the Solaris/OpenSolaris service management framework (SMF) system to initiate and control MySQL startup. For more information, see *Note solaris-installation-opensolaris::. The *Note `mysqld_safe': mysqld-safe. and *Note `mysql.server': mysql-server. scripts, Windows server, Solaris/OpenSolaris SMF, and the Mac OS X Startup Item (or MySQL Preference Pane) can be used to start the server manually, or automatically at system startup time. *Note `mysql.server': mysql-server. and the Startup Item also can be used to stop the server. To start or stop the server manually using the *Note `mysql.server': mysql-server. script, invoke it with `start' or `stop' arguments: shell> mysql.server start shell> mysql.server stop Before *Note `mysql.server': mysql-server. starts the server, it changes location to the MySQL installation directory, and then invokes *Note `mysqld_safe': mysqld-safe. If you want the server to run as some specific user, add an appropriate `user' option to the `[mysqld]' group of the `/etc/my.cnf' option file, as shown later in this section. (It is possible that you will need to edit *Note `mysql.server': mysql-server. if you've installed a binary distribution of MySQL in a nonstandard location. Modify it to change location into the proper directory before it runs *Note `mysqld_safe': mysqld-safe. If you do this, your modified version of *Note `mysql.server': mysql-server. may be overwritten if you upgrade MySQL in the future, so you should make a copy of your edited version that you can reinstall.) *Note `mysql.server stop': mysql-server. stops the server by sending a signal to it. You can also stop the server manually by executing *Note `mysqladmin shutdown': mysqladmin. To start and stop MySQL automatically on your server, you need to add start and stop commands to the appropriate places in your `/etc/rc*' files. If you use the Linux server RPM package (`MySQL-server-VERSION.rpm'), or a native Linux package installation, the *Note `mysql.server': mysql-server. script may be installed in the `/etc/init.d' directory with the name `mysql'. See *Note linux-installation-rpm::, for more information on the Linux RPM packages. Some vendors provide RPM packages that install a startup script under a different name such as *Note `mysqld': mysqld. If you install MySQL from a source distribution or using a binary distribution format that does not install *Note `mysql.server': mysql-server. automatically, you can install it manually. The script can be found in the `support-files' directory under the MySQL installation directory or in a MySQL source tree. To install *Note `mysql.server': mysql-server. manually, copy it to the `/etc/init.d' directory with the name *Note `mysql': mysql, and then make it executable. Do this by changing location into the appropriate directory where *Note `mysql.server': mysql-server. is located and executing these commands: shell> cp mysql.server /etc/init.d/mysql shell> chmod +x /etc/init.d/mysql *Note*: Older Red Hat systems use the `/etc/rc.d/init.d' directory rather than `/etc/init.d'. Adjust the preceding commands accordingly. Alternatively, first create `/etc/init.d' as a symbolic link that points to `/etc/rc.d/init.d': shell> cd /etc shell> ln -s rc.d/init.d . After installing the script, the commands needed to activate it to run at system startup depend on your operating system. On Linux, you can use `chkconfig': shell> chkconfig --add mysql On some Linux systems, the following command also seems to be necessary to fully enable the *Note `mysql': mysql. script: shell> chkconfig --level 345 mysql on On FreeBSD, startup scripts generally should go in `/usr/local/etc/rc.d/'. The `rc(8)' manual page states that scripts in this directory are executed only if their basename matches the `*.sh' shell file name pattern. Any other files or directories present within the directory are silently ignored. In other words, on FreeBSD, you should install the `mysql.server' script as `/usr/local/etc/rc.d/mysql.server.sh' to enable automatic startup. As an alternative to the preceding setup, some operating systems also use `/etc/rc.local' or `/etc/init.d/boot.local' to start additional services on startup. To start up MySQL using this method, you could append a command like the one following to the appropriate startup file: /bin/sh -c 'cd /usr/local/mysql; ./bin/mysqld_safe --user=mysql &' For other systems, consult your operating system documentation to see how to install startup scripts. You can add options for *Note `mysql.server': mysql-server. in a global `/etc/my.cnf' file. A typical `/etc/my.cnf' file might look like this: [mysqld] datadir=/usr/local/mysql/var socket=/var/tmp/mysql.sock port=3306 user=mysql [mysql.server] basedir=/usr/local/mysql The *Note `mysql.server': mysql-server. script supports the following options: `basedir', `datadir', and `pid-file'. If specified, they _must_ be placed in an option file, not on the command line. *Note `mysql.server': mysql-server. supports only `start' and `stop' as command-line arguments. The following table shows which option groups the server and each startup script read from option files. *MySQL Startup scripts and supported server option groups* Script Option Groups *Note `[mysqld]', `[server]', `[mysqld-MAJOR_VERSION]' `mysqld': mysqld. *Note `[mysqld]', `[server]', `[mysqld_safe]' `mysqld_safe': mysqld-safe. *Note `[mysqld]', `[mysql.server]', `[server]' `mysql.server': mysql-server. `[mysqld-MAJOR_VERSION]' means that groups with names like `[mysqld-5.0]' and `[mysqld-5.1]' are read by servers having versions 5.0.x, 5.1.x, and so forth. This feature can be used to specify options that can be read only by servers within a given release series. For backward compatibility, *Note `mysql.server': mysql-server. also reads the `[mysql_server]' group and *Note `mysqld_safe': mysqld-safe. also reads the `[safe_mysqld]' group. However, you should update your option files to use the `[mysql.server]' and `[mysqld_safe]' groups instead when using MySQL 5.1. For more information on MySQL configuration files and their structure and contents, see *Note option-files::.  File: manual.info, Node: starting-server, Prev: automatic-start, Up: unix-postinstallation 3.12.1.3 Starting and Troubleshooting the MySQL Server ...................................................... This section provides troubleshooting suggestions for problems starting the server on Unix. If you are using Windows, see *Note windows-troubleshooting::. If you have problems starting the server, here are some things to try: * Check the error log to see why the server does not start. * Specify any special options needed by the storage engines you are using. * Make sure that the server knows where to find the data directory. * Make sure that the server can access the data directory. The ownership and permissions of the data directory and its contents must be set such that the server can read and modify them. * Verify that the network interfaces the server wants to use are available. Some storage engines have options that control their behavior. You can create a `my.cnf' file and specify startup options for the engines that you plan to use. If you are going to use storage engines that support transactional tables (`InnoDB', *Note `NDB': mysql-cluster.), be sure that you have them configured the way you want before starting the server: If you are using `InnoDB' tables, see *Note innodb-configuration::. If you are using MySQL Cluster, see *Note mysql-cluster-configuration::. Storage engines will use default option values if you specify none, but it is recommended that you review the available options and specify explicit values for those for which the defaults are not appropriate for your installation. When the *Note `mysqld': mysqld. server starts, it changes location to the data directory. This is where it expects to find databases and where it expects to write log files. The server also writes the pid (process ID) file in the data directory. The data directory location is hardwired in when the server is compiled. This is where the server looks for the data directory by default. If the data directory is located somewhere else on your system, the server will not work properly. You can determine what the default path settings are by invoking *Note `mysqld': mysqld. with the `--verbose' and `--help' options. If the default locations do not match the MySQL installation layout on your system, you can override them by specifying options to *Note `mysqld': mysqld. or *Note `mysqld_safe': mysqld-safe. on the command line or in an option file. To specify the location of the data directory explicitly, use the `--datadir' option. However, normally you can tell *Note `mysqld': mysqld. the location of the base directory under which MySQL is installed and it looks for the data directory there. You can do this with the `--basedir' option. To check the effect of specifying path options, invoke *Note `mysqld': mysqld. with those options followed by the `--verbose' and `--help' options. For example, if you change location into the directory where *Note `mysqld': mysqld. is installed and then run the following command, it shows the effect of starting the server with a base directory of `/usr/local': shell> ./mysqld --basedir=/usr/local --verbose --help You can specify other options such as `--datadir' as well, but `--verbose' and `--help' must be the last options. Once you determine the path settings you want, start the server without `--verbose' and `--help'. If *Note `mysqld': mysqld. is currently running, you can find out what path settings it is using by executing this command: shell> mysqladmin variables Or: shell> mysqladmin -h HOST_NAME variables HOST_NAME is the name of the MySQL server host. If you get `Errcode 13' (which means `Permission denied') when starting *Note `mysqld': mysqld, this means that the privileges of the data directory or its contents do not permit server access. In this case, you change the permissions for the involved files and directories so that the server has the right to use them. You can also start the server as `root', but this raises security issues and should be avoided. On Unix, change location into the data directory and check the ownership of the data directory and its contents to make sure the server has access. For example, if the data directory is `/usr/local/mysql/var', use this command: shell> ls -la /usr/local/mysql/var If the data directory or its files or subdirectories are not owned by the login account that you use for running the server, change their ownership to that account. If the account is named `mysql', use these commands: shell> chown -R mysql /usr/local/mysql/var shell> chgrp -R mysql /usr/local/mysql/var If it possible that even with correct ownership, MySQL may fail to start up if there is other security software running on your system that manages application access to various parts of the file system. In this case, you may need to reconfigure that software to enable *Note `mysqld': mysqld. to access the directories it uses during normal operation. If the server fails to start up correctly, check the error log. Log files are located in the data directory (typically `C:\Program Files\MySQL\MySQL Server 5.1\data' on Windows, `/usr/local/mysql/data' for a Unix binary distribution, and `/usr/local/var' for a Unix source distribution). Look in the data directory for files with names of the form `HOST_NAME.err' and `HOST_NAME.log', where HOST_NAME is the name of your server host. Then examine the last few lines of these files. On Unix, you can use `tail' to display them: shell> tail HOST_NAME.err shell> tail HOST_NAME.log The error log should contain information that indicates why the server could not start. If either of the following errors occur, it means that some other program (perhaps another *Note `mysqld': mysqld. server) is using the TCP/IP port or Unix socket file that *Note `mysqld': mysqld. is trying to use: Can't start server: Bind on TCP/IP port: Address already in use Can't start server: Bind on unix socket... Use `ps' to determine whether you have another *Note `mysqld': mysqld. server running. If so, shut down the server before starting *Note `mysqld': mysqld. again. (If another server is running, and you really want to run multiple servers, you can find information about how to do so in *Note multiple-servers::.) If no other server is running, try to execute the command `telnet YOUR_HOST_NAME TCP_IP_PORT_NUMBER'. (The default MySQL port number is 3306.) Then press Enter a couple of times. If you do not get an error message like `telnet: Unable to connect to remote host: Connection refused', some other program is using the TCP/IP port that *Note `mysqld': mysqld. is trying to use. You will need to track down what program this is and disable it, or else tell *Note `mysqld': mysqld. to listen to a different port with the `--port' option. In this case, you will also need to specify the port number for client programs when connecting to the server using TCP/IP. Another reason the port might be inaccessible is that you have a firewall running that blocks connections to it. If so, modify the firewall settings to permit access to the port. If the server starts but you cannot connect to it, you should make sure that you have an entry in `/etc/hosts' that looks like this: 127.0.0.1 localhost If you cannot get *Note `mysqld': mysqld. to start, you can try to make a trace file to find the problem by using the `--debug' option. See MySQL Internals: Porting (http://forge.mysql.com/wiki/MySQL_Internals_Porting).  File: manual.info, Node: default-privileges, Prev: unix-postinstallation, Up: postinstallation 3.12.2 Securing the Initial MySQL Accounts ------------------------------------------ Part of the MySQL installation process is to set up the `mysql' database that contains the grant tables: * Windows distributions contain preinitialized grant tables. * On Unix, the *Note `mysql_install_db': mysql-install-db. program populates the grant tables. Some installation methods run this program for you. Others require that you execute it manually. For details, see *Note unix-postinstallation::. The `mysql.user' grant table defines the initial MySQL user accounts and their access privileges: * Some accounts have the user name `root'. These are superuser accounts that have all privileges and can do anything. The initial `root' account passwords are empty, so anyone can connect to the MySQL server as `root' _without a password_ and be granted all privileges. * On Windows, `root' accounts are created that permit connections from the local host only. Connections can be made by specifying the host name `localhost' or the IP address `127.0.0.1'. If the user selects the `Enable root access from remote machines' option during installation, the Windows installer creates another `root' account that permits connections from any host. * On Unix, each `root' account permits connections from the local host. Connections can be made by specifying the host name `localhost', the IP address `127.0.0.1', or the actual host name or IP address. An attempt to connect to the host `127.0.0.1' normally resolves to the `localhost' account. However, this fails if the server is run with the `--skip-name-resolve' option, so the `127.0.0.1' account is useful in that case. * Some accounts are for anonymous users. These have an empty user name. The anonymous accounts have no password, so anyone can use them to connect to the MySQL server. * On Windows, there is one anonymous account that permits connections from the local host. Connections can be made by specifying a host name of `localhost'. The account has no global privileges. (Before MySQL 5.1.16, it has all global privileges, just like the `root' accounts.) * On Unix, each anonymous account permits connections from the local host. Connections can be made by specifying a host name of `localhost' for one of the accounts, or the actual host name or IP address for the other. To display which accounts exist in the `mysql.user' table and check whether their passwords are empty, use the following statement: mysql> SELECT User, Host, Password FROM mysql.user; +------+--------------------+----------+ | User | Host | Password | +------+--------------------+----------+ | root | localhost | | | root | myhost.example.com | | | root | 127.0.0.1 | | | | localhost | | | | myhost.example.com | | +------+--------------------+----------+ This output indicates that there are several `root' and anonymous-user accounts, none of which have passwords. The output might differ on your system, but the presence of accounts with empty passwords means that your MySQL installation is unprotected until you do something about it: * You should assign a password to each MySQL `root' account. * If you want to prevent clients from connecting as anonymous users without a password, you should either assign a password to each anonymous account or else remove the accounts. In addition, the `mysql.db' table contains rows that permit all accounts to access the `test' database and other databases with names that start with `test_'. This is true even for accounts that otherwise have no special privileges such as the default anonymous accounts. This is convenient for testing but inadvisable on production servers. Administrators who want database access restricted only to accounts that have permissions granted explicitly for that purpose should remove these `mysql.db' table rows. The following instructions describe how to set up passwords for the initial MySQL accounts, first for the `root' accounts, then for the anonymous accounts. The instructions also cover how to remove the anonymous accounts, should you prefer not to permit anonymous access at all, and describe how to remove permissive access to test databases. Replace NEWPWD in the examples with the password that you want to use. Replace HOST_NAME with the name of the server host. You can determine this name from the output of the preceding *Note `SELECT': select. statement. For the output shown, HOST_NAME is `myhost.example.com'. *Note*: For additional information about setting passwords, see *Note assigning-passwords::. If you forget your `root' password after setting it, see *Note resetting-permissions::. You might want to defer setting the passwords until later, to avoid the need to specify them while you perform additional setup or testing. However, be sure to set them before using your installation for production purposes. To set up additional accounts, see *Note adding-users::. * Assigning `root' Account Passwords * The `root' account passwords can be set several ways. The following discussion demonstrates three methods: * Use the *Note `SET PASSWORD': set-password. statement * Use the *Note `UPDATE': update. statement * Use the *Note `mysqladmin': mysqladmin. command-line client program To assign passwords using *Note `SET PASSWORD': set-password, connect to the server as `root' and issue a *Note `SET PASSWORD': set-password. statement for each `root' account listed in the `mysql.user' table. Be sure to encrypt the password using the `PASSWORD()' function. For Windows, do this: shell> mysql -u root mysql> SET PASSWORD FOR 'root'@'localhost' = PASSWORD('NEWPWD'); mysql> SET PASSWORD FOR 'root'@'127.0.0.1' = PASSWORD('NEWPWD'); mysql> SET PASSWORD FOR 'root'@'%' = PASSWORD('NEWPWD'); The last statement is unnecessary if the `mysql.user' table has no `root' account with a host value of `%'. For Unix, do this: shell> mysql -u root mysql> SET PASSWORD FOR 'root'@'localhost' = PASSWORD('NEWPWD'); mysql> SET PASSWORD FOR 'root'@'127.0.0.1' = PASSWORD('NEWPWD'); mysql> SET PASSWORD FOR 'root'@'HOST_NAME' = PASSWORD('NEWPWD'); You can also use a single statement that assigns a password to all `root' accounts by using *Note `UPDATE': update. to modify the `mysql.user' table directly. This method works on any platform: shell> mysql -u root mysql> UPDATE mysql.user SET Password = PASSWORD('NEWPWD') -> WHERE User = 'root'; mysql> FLUSH PRIVILEGES; The *Note `FLUSH': flush. statement causes the server to reread the grant tables. Without it, the password change remains unnoticed by the server until you restart it. To assign passwords to the `root' accounts using *Note `mysqladmin': mysqladmin, execute the following commands: shell> mysqladmin -u root password "NEWPWD" shell> mysqladmin -u root -h HOST_NAME password "NEWPWD" Those commands apply both to Windows and to Unix. The double quotation marks around the password are not always necessary, but you should use them if the password contains spaces or other characters that are special to your command interpreter. The *Note `mysqladmin': mysqladmin. method of setting the `root' account passwords does not work for the `'root'@'127.0.0.1'' account. Use the *Note `SET PASSWORD': set-password. method shown earlier. After the `root' passwords have been set, you must supply the appropriate password whenever you connect as `root' to the server. For example, to shut down the server with *Note `mysqladmin': mysqladmin, use this command: shell> mysqladmin -u root -p shutdown Enter password: (ENTER ROOT PASSWORD HERE) * Assigning Anonymous Account Passwords * The *Note `mysql': mysql. commands in the following instructions include a `-p' option based on the assumption that you have set the `root' account passwords using the preceding instructions and must specify that password when connecting to the server. To assign passwords to the anonymous accounts, connect to the server as `root', then use either *Note `SET PASSWORD': set-password. or *Note `UPDATE': update. Be sure to encrypt the password using the `PASSWORD()' function. To use *Note `SET PASSWORD': set-password. on Windows, do this: shell> mysql -u root -p Enter password: (ENTER ROOT PASSWORD HERE) mysql> SET PASSWORD FOR ''@'localhost' = PASSWORD('NEWPWD'); To use *Note `SET PASSWORD': set-password. on Unix, do this: shell> mysql -u root -p Enter password: (ENTER ROOT PASSWORD HERE) mysql> SET PASSWORD FOR ''@'localhost' = PASSWORD('NEWPWD'); mysql> SET PASSWORD FOR ''@'HOST_NAME' = PASSWORD('NEWPWD'); To set the anonymous-user account passwords with a single *Note `UPDATE': update. statement, do this (on any platform): shell> mysql -u root -p Enter password: (ENTER ROOT PASSWORD HERE) mysql> UPDATE mysql.user SET Password = PASSWORD('NEWPWD') -> WHERE User = ''; mysql> FLUSH PRIVILEGES; The *Note `FLUSH': flush. statement causes the server to reread the grant tables. Without it, the password change remains unnoticed by the server until you restart it. * Removing Anonymous Accounts * If you prefer to remove any anonymous accounts rather than assigning them passwords, do so as follows on Windows: shell> mysql -u root -p Enter password: (ENTER ROOT PASSWORD HERE) mysql> DROP USER ''@'localhost'; On Unix, remove the anonymous accounts like this: shell> mysql -u root -p Enter password: (ENTER ROOT PASSWORD HERE) mysql> DROP USER ''@'localhost'; mysql> DROP USER ''@'HOST_NAME'; * Securing Test Databases * By default, the `mysql.db' table contains rows that permit access by any user to the `test' database and other databases with names that start with `test_'. (These rows have an empty `User' column value, which for access-checking purposes matches any user name.) This means that such databases can be used even by accounts that otherwise possess no privileges. If you want to remove any-user access to test databases, do so as follows: shell> mysql -u root -p Enter password: (ENTER ROOT PASSWORD HERE) mysql> DELETE FROM mysql.db WHERE Db LIKE 'test%'; mysql> FLUSH PRIVILEGES; The *Note `FLUSH': flush. statement causes the server to reread the grant tables. Without it, the privilege change remains unnoticed by the server until you restart it. With the preceding change, only users who have global database privileges or privileges granted explicitly for the `test' database can use it. However, if you do not want the database to exist at all, drop it: mysql> DROP DATABASE test; *Note*: On Windows, you can also perform the process described in this section using the Configuration Wizard (see *Note mysql-config-wizard-security::). On other platforms, the MySQL distribution includes *Note `mysql_secure_installation': mysql-secure-installation, a command-line utility that automates much of the process of securing a MySQL installation.  File: manual.info, Node: upgrading-downgrading, Next: environment-variables, Prev: postinstallation, Up: installing 3.13 Upgrading or Downgrading MySQL =================================== * Menu: * upgrading:: Upgrading MySQL * downgrading:: Downgrading MySQL * checking-table-incompatibilities:: Checking Whether Tables or Indexes Must Be Rebuilt * rebuilding-tables:: Rebuilding or Repairing Tables or Indexes * copying-databases:: Copying MySQL Databases to Another Machine  File: manual.info, Node: upgrading, Next: downgrading, Prev: upgrading-downgrading, Up: upgrading-downgrading 3.13.1 Upgrading MySQL ---------------------- * Menu: * upgrading-from-previous-series:: Upgrading from MySQL 5.0 to 5.1 As a general rule, to upgrade from one release series to another, you should go to the next series rather than skipping a series. To upgrade from a release series previous to MySQL 5.0, upgrade to each successive release series in turn until you have reached MySQL 5.0, and then proceed with the upgrade to MySQL 5.1. For example, if you currently are running MySQL 4.1 and wish to upgrade to a newer series, upgrade to MySQL 5.0 first before upgrading to 5.1, and so forth. For information on upgrading to MySQL 5.0, see the `MySQL 5.0 Reference Manual'; for earlier releases, see the `MySQL 3.23, 4.0, 4.1 Reference Manual'. If you perform a binary (in-place) upgrade without dumping and reloading tables, you cannot upgrade directly from MySQL 4.1 to 5.1. This occurs due to an incompatible change in the `MyISAM' table index format in MySQL 5.0. Upgrade from MySQL 4.1 to 5.0 and repair all `MyISAM' tables (see *Note rebuilding-tables::). Then upgrade from MySQL 5.0 to 5.1 and check and repair your tables. To upgrade from MySQL 5.0 to 5.1, use the items in the following checklist as a guide: * Before any upgrade, back up your databases, including the `mysql' database that contains the grant tables. See *Note backup-methods::. * Read _all_ the notes in *Note upgrading-from-previous-series::. These notes enable you to identify upgrade issues that apply to your current MySQL installation. Some incompatibilities discussed in that section require your attention _before_ upgrading. Others should be dealt with _after_ upgrading. * Read *Note news:: as well, which provides information about features that are new in MySQL 5.1 or differ from those found in MySQL 5.0. * After upgrading to a new version of MySQL, run *Note `mysql_upgrade': mysql-upgrade. (see *Note mysql-upgrade::). This program checks your tables, and attempts to repair them if necessary. It also updates your grant tables to make sure that they have the current structure so that you can take advantage of any new capabilities. (Some releases of MySQL introduce changes to the structure of the grant tables to add new privileges or features.) *Note `mysql_upgrade': mysql-upgrade. does not upgrade the contents of the help tables. For upgrade instructions, see *Note server-side-help-support::. * If you run MySQL Server on Windows, see *Note windows-upgrading::. * If you use replication, see *Note replication-upgrade::, for information on upgrading your replication setup. * If you upgrade an installation originally produced by installing multiple RPM packages, it is best to upgrade all the packages, not just some. For example, if you previously installed the server and client RPMs, do not upgrade just the server RPM. * As of MySQL 5.1.9, the `mysqld-max' server is included in binary distributions. There is no separate MySQL-Max distribution. As of MySQL 5.1.12, there is no `mysqld-max' server at all in binary distributions. They contain a server that includes the features previously included in `mysqld-max'. * If you have created a user-defined function (UDF) with a given name and upgrade MySQL to a version that implements a new built-in function with the same name, the UDF becomes inaccessible. To correct this, use *Note `DROP FUNCTION': drop-function. to drop the UDF, and then use *Note `CREATE FUNCTION': create-function. to re-create the UDF with a different nonconflicting name. The same is true if the new version of MySQL implements a built-in function with the same name as an existing stored function. See *Note function-resolution::, for the rules describing how the server interprets references to different kinds of functions. You can always move the MySQL format files and data files between different versions on systems with the same architecture as long as you stay within versions for the same release series of MySQL. If you are cautious about using new versions, you can always rename your old *Note `mysqld': mysqld. before installing a newer one. For example, if you are using MySQL 5.0.13 and want to upgrade to 5.1.10, rename your current server from *Note `mysqld': mysqld. to `mysqld-5.0.13'. If your new *Note `mysqld': mysqld. then does something unexpected, you can simply shut it down and restart with your old *Note `mysqld': mysqld. If, after an upgrade, you experience problems with compiled client programs, such as `Commands out of sync' or unexpected core dumps, you probably have used old header or library files when compiling your programs. In this case, you should check the date for your `mysql.h' file and `libmysqlclient.a' library to verify that they are from the new MySQL distribution. If not, recompile your programs with the new headers and libraries. Recompilation might also be necessary for programs compiled against the shared client library if the library major version number has changed (for example from `libmysqlclient.so.15' to `libmysqlclient.so.16'. If problems occur, such as that the new *Note `mysqld': mysqld. server does not start or that you cannot connect without a password, verify that you do not have an old `my.cnf' file from your previous installation. You can check this with the `--print-defaults' option (for example, *Note `mysqld --print-defaults': mysqld.). If this command displays anything other than the program name, you have an active `my.cnf' file that affects server or client operation. If your MySQL installation contains a large amount of data that might take a long time to convert after an in-place upgrade, you might find it useful to create a `dummy' database instance for assessing what conversions might be needed and the work involved to perform them. Make a copy of your MySQL instance that contains a full copy of the `mysql' database, plus all other databases without data. Run your upgrade procedure on this dummy instance to see what actions might be needed so that you can better evaluate the work involved when performing actual data conversion on your original database instance. It is a good idea to rebuild and reinstall the Perl `DBD::mysql' module whenever you install a new release of MySQL. The same applies to other MySQL interfaces as well, such as PHP `mysql' extensions and the Python `MySQLdb' module.  File: manual.info, Node: upgrading-from-previous-series, Prev: upgrading, Up: upgrading 3.13.1.1 Upgrading from MySQL 5.0 to 5.1 ........................................ *After upgrading a 5.0 installation to 5.0.10 or above*, it is _necessary_ to upgrade your grant tables. Otherwise, creating stored procedures and functions might not work. To perform this upgrade, run *Note `mysql_upgrade': mysql-upgrade. *Note*: It is good practice to back up your data before installing any new version of software. Although MySQL works very hard to ensure a high level of quality, you should protect your data by making a backup. To upgrade to 5.1 from any previous version, MySQL recommends that you dump your tables with *Note `mysqldump': mysqldump. before upgrading and reload the dump file after upgrading. If you perform a binary (in-place) upgrade without dumping and reloading tables, you cannot upgrade directly from MySQL 4.1 to 5.1. This occurs due to an incompatible change in the `MyISAM' table index format in MySQL 5.0. Upgrade from MySQL 4.1 to 5.0 and repair all `MyISAM' tables (see *Note rebuilding-tables::). Then upgrade from MySQL 5.0 to 5.1 and check and repair your tables. In general, you should do the following when upgrading from MySQL 5.0 to 5.1: * Read _all_ the items in the following sections to see whether any of them might affect your applications: * *Note upgrading::, has general update information. * The items in the change lists found later in this section enable you to identify upgrade issues that apply to your current MySQL installation. * The MySQL 5.1 change history describes significant new features you can use in 5.1 or that differ from those found in MySQL 5.0. Some of these changes may result in incompatibilities. See *Note news-5-1-x::. Note particularly any changes that are marked *Known issue* or *Incompatible change*. These incompatibilities with earlier versions of MySQL may require your attention _before you upgrade_. Our aim is to avoid these changes, but occasionally they are necessary to correct problems that would be worse than an incompatibility between releases. If any upgrade issue applicable to your installation involves an incompatibility that requires special handling, follow the instructions given in the incompatibility description. Often this will involve dumping and reloading tables, or use of a statement such as *Note `CHECK TABLE': check-table. or *Note `REPAIR TABLE': repair-table. For dump and reload instructions, see *Note rebuilding-tables::. Any procedure that involves *Note `REPAIR TABLE': repair-table. with the `USE_FRM' option _must_ be done before upgrading. Use of this statement with a version of MySQL different from the one used to create the table (that is, using it after upgrading) may damage the table. See *Note repair-table::. * Before upgrading to a new version of MySQL, *Note checking-table-incompatibilities::, to see whether changes to table formats or to character sets or collations were made between your current version of MySQL and the version to which you are upgrading. If so and these changes result in an incompatibility between MySQL versions, you will need to upgrade the affected tables using the instructions in *Note rebuilding-tables::. * After upgrading to a new version of MySQL, run *Note `mysql_upgrade': mysql-upgrade. (see *Note mysql-upgrade::). This program checks your tables, and attempts to repair them if necessary. It also updates your grant tables to make sure that they have the current structure so that you can take advantage of any new capabilities. (Some releases of MySQL introduce changes to the structure of the grant tables to add new privileges or features.) *Note `mysql_upgrade': mysql-upgrade. does not upgrade the contents of the help tables. For upgrade instructions, see *Note server-side-help-support::. * If you run MySQL Server on Windows, see *Note windows-upgrading::. * If you use replication, see *Note replication-upgrade::, for information on upgrading your replication setup. If your MySQL installation contains a large amount of data that might take a long time to convert after an in-place upgrade, you might find it useful to create a `dummy' database instance for assessing what conversions might be needed and the work involved to perform them. Make a copy of your MySQL instance that contains a full copy of the `mysql' database, plus all other databases without data. Run your upgrade procedure on this dummy instance to see what actions might be needed so that you can better evaluate the work involved when performing actual data conversion on your original database instance. The following lists describe changes that may affect applications and that you should watch out for when upgrading from MySQL 5.0 to 5.1. * Configuration Changes * * Before MySQL 5.1.11, to build MySQL from source with SSL support enabled, you would invoke `configure' with either the `--with-openssl' or `--with-yassl' option. In MySQL 5.1.11, those options both have been replaced by the `--with-ssl' option. By default, `--with-ssl' causes the bundled yaSSL library to be used. To select OpenSSL instead, give the option as `--with-ssl=PATH', where PATH is the directory where the OpenSSL header files and libraries are located. * Server Changes * * *Known issue*: *Note `mysql_upgrade': mysql-upgrade. attempts to to upgrade tables that are incompatible with the current version of MySQL. (It invokes *Note `mysqlcheck': mysqlcheck. to check tables and, if necessary, repair them.) However this can fail for storage engines that do not support REPAIR TABLE, such as *Note `InnoDB': innodb-storage-engine, and leave tables in a nonupgradable state. To work around this problem, use *Note `ALTER TABLE TBL_NAME ENGINE=InnoDB': alter-table. to perform a `null' alter operation that rebuilds the table. * *Known issue*: After a binary upgrade to MySQL 5.1 from a MySQL 5.0 installation that contains *Note `ARCHIVE': archive-storage-engine. tables: * Before MySQL 5.1.42, accessing those tables will cause the server to crash, even if you have run *Note `mysql_upgrade': mysql-upgrade. or *Note `CHECK TABLE ... FOR UPGRADE': check-table. * As of MySQL 5.1.42, the server will not open 5.0 *Note `ARCHIVE': archive-storage-engine. tables at all. In either case, the solution is to use *Note `mysqldump': mysqldump. to dump all 5.0 *Note `ARCHIVE': archive-storage-engine. tables before upgrading, and reload them into MySQL 5.1 after upgrading. * *Known issue*: The fix for Bug#23491 introduced a problem with *Note `SHOW CREATE VIEW': show-create-view, which is used by *Note `mysqldump': mysqldump. This causes an incompatibility when upgrading from versions affected by that bug fix (MySQL 5.0.40 through 5.0.43, MySQL 5.1.18 through 5.1.19): If you use *Note `mysqldump': mysqldump. before upgrading from an affected version and reload the data after upgrading to a higher version, you must drop and recreate your views. * *Known issue*: Dumps performed by using *Note `mysqldump': mysqldump. to generate a dump file before the upgrade and reloading the file after upgrading are subject to the following problem: Before MySQL 5.0.40, *Note `mysqldump': mysqldump. displays `SPATIAL' index definitions using prefix lengths for the indexed columns. These prefix lengths are accepted in MySQL 5.0, but not as of MySQL 5.1. If you use *Note `mysqldump': mysqldump. from versions of MySQL older than 5.0.40, any table containing `SPATIAL' indexes will cause an error when the dump file is reloaded into MySQL 5.1 or higher. For example, a table definition might look like this when dumped in MySQL 5.0: CREATE TABLE `t` ( `g` geometry NOT NULL, SPATIAL KEY `g` (`g`(32)) ) ENGINE=MyISAM DEFAULT CHARSET=latin1 The `SPATIAL' index definition will not be accepted in MySQL 5.1. To work around this, edit the dump file to remove the prefix: CREATE TABLE `t` ( `g` geometry NOT NULL, SPATIAL KEY `g` (`g`) ) ENGINE=MyISAM DEFAULT CHARSET=latin1 Dump files can be large, so it may be preferable to dump table definitions and data separately to make it easier to edit the definitions: shell> mysqldump --no-data OTHER_ARGS > definitions.sql shell> mysqldump --no-create-info OTHER_ARGS > data.sql Then edit `definitions.sql' before reloading `definitions.sql' and `data.sql', in that order. If you upgrade to a version of MySQL 5.0 higher than 5.0.40 before upgrading to MySQL 5.1, this problem does not occur. * *Known issue*: Before MySQL 5.1.30, the *Note `CHECK TABLE ... FOR UPGRADE': check-table. statement did not check for incompatible collation changes made in MySQL 5.1.24. (This also affects *Note `mysqlcheck': mysqlcheck. and *Note `mysql_upgrade': mysql-upgrade, which cause that statement to be executed.) Prior to the fix made in 5.1.30, a binary upgrade (performed without dumping tables with *Note `mysqldump': mysqldump. before the upgrade and reloading the dump file after the upgrade) would corrupt tables. After the fix, *Note `CHECK TABLE ... FOR UPGRADE': check-table. properly detects the problem and warns about tables that need repair. However, the fix is not backward compatible and can result in a downgrading problem under these circumstances: 1. Perform a binary upgrade to a version of MySQL that includes the fix. 2. Run *Note `CHECK TABLE ... FOR UPGRADE': check-table. (or *Note `mysqlcheck': mysqlcheck. or *Note `mysql_upgrade': mysql-upgrade.) to upgrade tables. 3. Perform a binary downgrade to a version of MySQL that does not include the fix. The solution is to dump tables with *Note `mysqldump': mysqldump. before the downgrade and reload the dump file after the downgrade. Alternatively, drop and recreate affected indexes. * *Known issue*: MySQL introduces encoding for table names that have non-ASCII characters (see *Note identifier-mapping::). After a binary upgrade from MySQL 5.0 to 5.1 or higher, the server recognizes names that have non-ASCII characters and adds a `#mysql50#' prefix to them. As of MySQL 5.1.31, *Note `mysql_upgrade': mysql-upgrade. encodes these names by executing the following command: mysqlcheck --all-databases --check-upgrade --fix-db-names --fix-table-names Prior to MySQL 5.1.31, *Note `mysql_upgrade': mysql-upgrade. does not execute this command, so you should execute it manually if you have database or table names that contain nonalphanumeric characters. Prior to MySQL 5.1.23, the *Note `mysqlcheck': mysqlcheck. command does not perform the name encoding for views. To work around this problem, drop each affected view and recreate it. *Note `mysqlcheck': mysqlcheck. cannot fix names that contain literal instances of the `@' character that is used for encoding special characters. If you have databases or tables that contain this character, use *Note `mysqldump': mysqldump. to dump them before upgrading to MySQL 5.1, and then reload the dump file after upgrading. * *Known issue*: When upgrading from MySQL 5.0 to versions of 5.1 prior to 5.1.23, running *Note `mysqlcheck': mysqlcheck. (or *Note `mysql_upgrade': mysql-upgrade, which runs *Note `mysqlcheck': mysqlcheck.) to upgrade tables fails for names that must be written as quoted identifiers. To work around this problem, rename each affected table to a name that does not require quoting: RENAME TABLE `tab``le_a` TO table_a; RENAME TABLE `table b` TO table_b; After renaming the tables, run the *Note `mysql_upgrade': mysql-upgrade. program. Then rename the tables back to their original names: RENAME TABLE table_a TO `tab``le_a`; RENAME TABLE table_b TO `table b`; * *Known issue*: In connection with view creation, the server created `arc' directories inside database directories and maintained useless copies of `.frm' files there. Creation and renaming procedures of those copies as well as creation of `arc' directories has been discontinued in MySQL 5.1.29. This change does cause a problem when downgrading to older server versions which manifests itself under these circumstances: 1. Create a view `v_orig' in MySQL 5.1.29 or higher. 2. Rename the view to `v_new' and then back to `v_orig'. 3. Downgrade to an older 5.1.x server and run *Note `mysql_upgrade': mysql-upgrade. 4. Try to rename `v_orig' to `v_new' again. This operation fails. As a workaround to avoid this problem, use either of these approaches: * Dump your data using *Note `mysqldump': mysqldump. before downgrading and reload the dump file after downgrading. * Instead of renaming a view after the downgrade, drop it and recreate it. * *Incompatible change*: As of MySQL 5.5.6, handling of *Note `CREATE TABLE IF NOT EXISTS ... SELECT': create-table-select. statements has been changed for the case that the destination table already exists: * Previously, for *Note `CREATE TABLE IF NOT EXISTS ... SELECT': create-table-select, MySQL produced a warning that the table exists, but inserted the rows and wrote the statement to the binary log anyway. By contrast, *Note `CREATE TABLE ... SELECT': create-table-select. (without `IF NOT EXISTS') failed with an error, but MySQL inserted no rows and did not write the statement to the binary log. * MySQL now handles both statements the same way when the destination table exists, in that neither statement inserts rows or is written to the binary log. The difference between them is that MySQL produces a warning when `IF NOT EXISTS' is present and an error when it is not. This change in handling of `IF NOT EXISTS' results in an incompatibility for statement-based replication from a MySQL 5.1 master with the original behavior and a MySQL 5.5 slave with the new behavior. Suppose that *Note `CREATE TABLE IF NOT EXISTS ... SELECT': create-table-select. is executed on the master and the destination table exists. The result is that rows are inserted on the master but not on the slave. (Row-based replication does not have this problem.) To address this issue, statement-based binary logging for *Note `CREATE TABLE IF NOT EXISTS ... SELECT': create-table-select. is changed in MySQL 5.1 as of 5.1.51: * If the destination table does not exist, there is no change: The statement is logged as is. * If the destination table does exist, the statement is logged as the equivalent pair of *Note `CREATE TABLE IF NOT EXISTS': create-table-select. and *Note `INSERT ... SELECT': insert-select. statements. (If the *Note `SELECT': select. in the original statement is preceded by `IGNORE' or *Note `REPLACE': replace, the *Note `INSERT': insert. becomes *Note `INSERT IGNORE': insert. or *Note `REPLACE': replace, respectively.) This change provides forward compatibility for statement-based replication from MySQL 5.1 to 5.5 because when the destination table exists, the rows will be inserted on both the master and slave. To take advantage of this compatibility measure, the 5.1 server must be at least 5.1.51 and the 5.5 server must be at least 5.5.6. To upgrade an existing 5.1-to-5.5 replication scenario, upgrade the master first to 5.1.51 or higher. Note that this differs from the usual replication upgrade advice of upgrading the slave first. A workaround for applications that wish to achieve the original effect (rows inserted regardless of whether the destination table exists) is to use *Note `CREATE TABLE IF NOT EXISTS': create-table-select. and *Note `INSERT ... SELECT': insert-select. statements rather than *Note `CREATE TABLE IF NOT EXISTS ... SELECT': create-table-select. statements. Along with the change just described, the following related change was made: Previously, if an existing view was named as the destination table for *Note `CREATE TABLE IF NOT EXISTS ... SELECT': create-table-select, rows were inserted into the underlying base table and the statement was written to the binary log. As of MySQL 5.1.51 and 5.5.6, nothing is inserted or logged. * *Incompatible change*: Prior to MySQL 5.1.51, if you flushed the logs using *Note `FLUSH LOGS': flush. or *Note `mysqladmin flush-logs': mysqladmin. and *Note `mysqld': mysqld. was writing the error log to a file (for example, if it was started with the `--log-error' option), it renames the current log file with the suffix `-old', then created a new empty log file. This had the problem that a second log-flushing operation thus caused the original error log file to be lost unless you saved it under a different name. For example, you could use the following commands to save the file: shell> mysqladmin flush-logs shell> mv HOST_NAME.err-old BACKUP-DIRECTORY To avoid the preceding file-loss problem, no renaming occurs as of MySQL 5.1.51; the server merely closes and reopens the log file. To rename the file, you can do so manually before flushing. Then flushing the logs reopens a new file with the original file name. For example, you can rename the file and create a new one using the following commands: shell> mv HOST_NAME.err HOST_NAME.err-old shell> mysqladmin flush-logs shell> mv HOST_NAME.err-old BACKUP-DIRECTORY * *Incompatible change*: Character set or collation changes were made in MySQL 5.1.21, 5.1.23, and 5.1.24 that may require table indexes to be rebuilt. For details, see *Note checking-table-incompatibilities::. * *Incompatible change*: MySQL 5.1 implements support for a plugin API that enables the loading and unloading of components at runtime, without restarting the server. *Note plugin-api::. The plugin API requires the `mysql.plugin' table. After upgrading from an older version of MySQL, you should run the *Note `mysql_upgrade': mysql-upgrade. command to create this table. See *Note mysql-upgrade::. Plugins are installed in the directory named by the `plugin_dir' system variable. This variable also controls the location from which the server loads user-defined functions (UDFs), which is a change from earlier versions of MySQL. That is, all UDF library files now must be installed in the plugin directory. When upgrading from an older version of MySQL, you must migrate your UDF files to the plugin directory. * *Incompatible change*: The `table_cache' system variable has been renamed to `table_open_cache'. Any scripts that refer to `table_cache' must be updated to use the new name. * *Incompatible change*: In MySQL 5.1.36, options for loading plugins such as pluggable storage engines were changed from boolean to tristate format. The implementations overlap, but if you previously used options of the form `--PLUGIN_NAME=0' or `--PLUGIN_NAME=1', you should instead use `--PLUGIN_NAME=OFF' or `--PLUGIN_NAME=ON', respectively. For details, see *Note server-plugin-loading::. * *Incompatible change*: From MySQL 5.1.24 to 5.1.31, the *Note `UPDATE': update. statement was changed such that assigning `NULL' to a `NOT NULL' column caused an error even when strict SQL mode was not enabled. The original behavior before MySQL 5.1.24 was that such assignments caused an error only in strict SQL mode, and otherwise set the column to the implicit default value for the column data type and generated a warning. (For information about implicit default values, see *Note data-type-defaults::.) The change caused compatibility problems for applications that relied on the original behavior. It also caused replication problems between servers that had the original behavior and those that did not, for applications that assigned `NULL' to `NOT NULL' columns in *Note `UPDATE': update. statements without strict SQL mode enabled. The change was reverted in MySQL 5.1.32 so that *Note `UPDATE': update. again had the original behavior. Problems can still occur if you replicate between servers that have the modified *Note `UPDATE': update. behavior and those that do not. * *Incompatible change*: As of MySQL 5.1.29, the default binary logging mode has been changed from `MIXED' to `STATEMENT' for compatibility with MySQL 5.0. * *Incompatible change*: In MySQL 5.1.25, a change was made to the way that the server handles prepared statements. This affects prepared statements processed at the SQL level (using the *Note `PREPARE': prepare. statement) and those processed using the binary client/server protocol (using the *Note `mysql_stmt_prepare()': mysql-stmt-prepare. C API function). Previously, changes to metadata of tables or views referred to in a prepared statement could cause a server crash when the statement was next executed, or perhaps an error at execute time with a crash occurring later. For example, this could happen after dropping a table and recreating it with a different definition. Now metadata changes to tables or views referred to by prepared statements are detected and cause automatic repreparation of the statement when it is next executed. Metadata changes occur for DDL statements such as those that create, drop, alter, rename, or truncate tables, or that analyze, optimize, or repair tables. Repreparation also occurs after referenced tables or views are flushed from the table definition cache, either implicitly to make room for new entries in the cache, or explicitly due to *Note `FLUSH TABLES': flush. Repreparation is automatic, but to the extent that it occurs, performance of prepared statements is diminished. Table content changes (for example, with *Note `INSERT': insert. or *Note `UPDATE': update.) do not cause repreparation, nor do *Note `SELECT': select. statements. An incompatibility with previous versions of MySQL is that a prepared statement may now return a different set of columns or different column types from one execution to the next. For example, if the prepared statement is `SELECT * FROM t1', altering `t1' to contain a different number of columns causes the next execution to return a number of columns different from the previous execution. Older versions of the client library cannot handle this change in behavior. For applications that use prepared statements with the new server, an upgrade to the new client library is strongly recommended. Along with this change to statement repreparation, the default value of the `table_definition_cache' system variable has been increased from 128 to 256. The purpose of this increase is to lessen the chance that prepared statements will need repreparation due to referred-to tables/views having been flushed from the cache to make room for new entries. A new status variable, `Com_stmt_reprepare', has been introduced to track the number of repreparations. * *Incompatible change*: The `-', `*', and `/' operators and the functions `POW()' and `EXP()' could misbehave when used with floating-point numbers. Previously they might return `+INF', `-INF', or `NaN' in cases of numeric overflow (including that caused by division by zero) or when invalid arguments were used. As of MySQL 5.1.24, `NULL' is returned in all such cases. * *Incompatible change*: As of MySQL 5.1.23, within a stored routine, it is no longer permissible to declare a cursor for a *Note `SHOW': show. or *Note `DESCRIBE': describe. statement. This happened to work in some instances, but is no longer supported. In many cases, a workaround for this change is to use the cursor with a *Note `SELECT': select. query to read from an `INFORMATION_SCHEMA' table that produces the same information as the *Note `SHOW': show. statement. * *Incompatible change*: *Note `SHOW CREATE VIEW': show-create-view. displays view definitions using an `AS ALIAS_NAME' clause for each column. If a column is created from an expression, the default alias is the expression text, which can be quite long. As of MySQL 5.1.23, aliases for column names in *Note `CREATE VIEW': create-view. statements are checked against the maximum column length of 64 characters (not the maximum alias length of 256 characters). As a result, views created from the output of *Note `SHOW CREATE VIEW': show-create-view. fail if any column alias exceeds 64 characters. This can cause problems for replication or loading dump files. For additional information and workarounds, see *Note view-restrictions::. * *Incompatible change*: Several issues were identified for stored programs (stored procedures and functions, triggers, and events) and views containing non-ASCII symbols. These issues involved conversion errors due to incomplete character set information when translating these objects to and from stored format. To address these problems, the representation for these objects was changed in MySQL 5.1.21. However, the fixes affect _all_ stored programs and views. (For example, you will see warnings about `no creation context.') To avoid warnings from the server about the use of old definitions from any release prior to 5.1.21, you should dump stored programs and views with *Note `mysqldump': mysqldump. after upgrading to 5.1.21 or higher, and then reload them to recreate them with new definitions. Invoke *Note `mysqldump': mysqldump. with a `--default-character-set' option that names the non-ASCII character set that was used for the definitions when the objects were originally created. Upgrading for triggers in particular must be handled carefully, for two reasons: * The output from *Note `mysqldump': mysqldump. does not contain a *Note `DROP TRIGGER': drop-trigger. statement preceding each *Note `CREATE TRIGGER': create-trigger. statement, so reloading the dump file will fail to re-create the triggers unless you manually drop them after generating the dump file and before reloading it. * If you are upgrading from a very old version of MySQL 5.0 (before 5.0.10), the trigger upgrade procedure is different because triggers for those versions were created using a different namespace (trigger names had to be unique per table, rather than per schema as is true now). For instructions on upgrading triggers from old 5.0 versions, see Upgrading from MySQL 4.1 to 5.0 (http://dev.mysql.com/doc/refman/5.0/en/upgrading-from-previous-series.html). Assuming that you are upgrading from MySQL 5.0.10 to 5.1.20 to MySQL 5.1.21 or later, use the following procedure to upgrade your triggers: * Use *Note `mysqldump': mysqldump. to generate a dump file that contains the trigger definitions: mysqldump --triggers--no-create-db --no-data --no-create-info --all-databases > triggers.sql You might need to add options to specify connection parameters, such as `--user' or `--password'. Also, if you are updating from a version of MySQL 5.1 older than 5.1.21, you may need to include a `--default-character-set' option that specifies the non-ASCII character set that was used for the definitions when the triggers were originally created. Otherwise, invoke *Note `mysqldump': mysqldump. with exactly the preceding options to avoid generating a dump file that will not have the intended effect when reloaded. For example, if you omit the `--no-create-db' option, your databases will be removed and recreated with no contents when you reload the dump file. * Drop existing triggers. To see which triggers exist, use this statement: SELECT TRIGGER_SCHEMA, EVENT_OBJECT_TABLE, TRIGGER_NAME FROM INFORMATION_SCHEMA.TRIGGERS; To generate `DROP TRIGGERS' statements for the triggers, use this statement: SELECT CONCAT('DROP TRIGGER ', TRIGGER_SCHEMA, '.', TRIGGER_NAME, ';') FROM INFORMATION_SCHEMA.TRIGGERS INTO OUTFILE '/tmp/drop_triggers.sql'; The statement uses `INTO OUTFILE', so you must have the `FILE' privilege. The file will be created on the server host. Use a different file name if you like. To be 100% safe, inspect the trigger definitions in the `drop_triggers.sql' file, and perhaps make a backup of the file. Then execute the statements in the file: mysql --force < /tmp/drop_triggers.sql * Recreate the triggers by reloading the dump file created earlier: mysql --force < triggers.sql * *Incompatible change*: As of MySQL 5.1.20, *Note `mysqld_safe': mysqld-safe. supports error logging to `syslog' on systems that support the `logger' command. The new `--syslog' and `--skip-syslog' options can be used instead of the `--log-error' option to control logging behavior, as described in *Note mysqld-safe::. In 5.1.21 and up, the default is `--skip-syslog', which is compatible with the default behavior of writing an error log file for releases prior to 5.1.20. *In 5.1.20 _only_, the following conditions apply*: 1) The default is to use `syslog', which is not compatible with releases prior to 5.1.20. 2) Logging to `syslog' may fail to operate correctly in some cases. For these reasons, avoid using MySQL 5.1.20. * *Incompatible change*: As of MySQL 5.1.18, the plugin interface and its handling of system variables was changed. Command-line options such as `--skip-innodb' now cause an error if `InnoDB' is not built-in or plugin-loaded. You should use `--loose-skip-innodb' if you do not want any error even if `InnoDB' is not available. The `--loose' prefix modifier should be used for all command-line options where you are uncertain whether the plugin exists and when you want the operation to proceed even if the option is necessarily ignored due to the absence of the plugin. (For a desecription of how `--loose' works, see *Note command-line-options::.) * *Incompatible change*: As of MySQL 5.1.15, `InnoDB' rolls back only the last statement on a transaction timeout. A new option, `--innodb_rollback_on_timeout', causes `InnoDB' to abort and roll back the entire transaction if a transaction timeout occurs (the same behavior as in MySQL 4.1). * *Incompatible change*: As of MySQL 5.1.15, the following conditions apply to enabling the `read_only' system variable: * If you attempt to enable `read_only' while you have any explicit locks (acquired with *Note `LOCK TABLES': lock-tables. or have a pending transaction, an error will occur. * If other clients hold explicit table locks or have pending transactions, the attempt to enable `read_only' blocks until the locks are released and the transactions end. While the attempt to enable `read_only' is pending, requests by other clients for table locks or to begin transactions also block until `read_only' has been set. * `read_only' can be enabled while you hold a global read lock (acquired with *Note `FLUSH TABLES WITH READ LOCK': flush.) because that does not involve table locks. Previously, the attempt to enable `read_only' would return immediately even if explicit locks or transactions were pending, so some data changes could occur for statements executing in the server at the same time. * *Incompatible change*: The number of function names affected by `IGNORE_SPACE' was reduced significantly in MySQL 5.1.13, from about 200 to about 30. (For details about `IGNORE_SPACE', see *Note function-resolution::.) This change improves the consistency of parser operation. However, it also introduces the possibility of incompatibility for old SQL code that relies on the following conditions: * `IGNORE_SPACE' is disabled. * The presence or absence of whitespace following a function name is used to distinguish between a built-in function and stored function that have the same name (for example, `PI()' versus `PI ()'). For functions that are no longer affected by `IGNORE_SPACE' as of MySQL 5.1.13, that strategy no longer works. Either of the following approaches can be used if you have code that is subject to the preceding incompatibility: * If a stored function has a name that conflicts with a built-in function, refer to the stored function with a schema name qualifier, regardless of whether whitespace is present. For example, write `SCHEMA_NAME.PI()' or `SCHEMA_NAME.PI ()'. * Alternatively, rename the stored function to use a nonconflicting name and change invocations of the function to use the new name. * *Incompatible change*: For `utf8' columns, the full-text parser incorrectly considered several nonword punctuation and whitespace characters as word characters, causing some searches to return incorrect results. The fix involves a change to the full-text parser in MySQL 5.1.12, so as of 5.1.12, any tables that have `FULLTEXT' indexes on `utf8' columns must be repaired with *Note `REPAIR TABLE': repair-table.: REPAIR TABLE TBL_NAME QUICK; * *Incompatible change*: Storage engines can be pluggable at runtime, so the distinction between disabled and invalid storage engines no longer applies. As of MySQL 5.1.12, this affects the `NO_ENGINE_SUBSTITUTION' SQL mode, as described in *Note server-sql-mode::. * *Incompatible change*: The structure of `FULLTEXT' indexes has been changed in MySQL 5.1.6. After upgrading to MySQL 5.1.6 or greater, any tables that have `FULLTEXT' indexes must be repaired with *Note `REPAIR TABLE': repair-table.: REPAIR TABLE TBL_NAME QUICK; * *Incompatible change*: In MySQL 5.1.6, when log tables were implemented, the default log destination for the general query and slow query log was `TABLE'. As of MySQL 5.1.21, this default has been changed to `FILE', which is compatible with MySQL 5.0, but incompatible with earlier releases of MySQL 5.1. If you are upgrading from MySQL 5.0 to 5.1.21 or higher, no logging option changes should be necessary. However, if you are upgrading from 5.1.6 through 5.1.20 to 5.1.21 or higher and were using `TABLE' logging, use the `--log-output=TABLE' option explicitly to preserve your server's table-logging behavior. * *Incompatible change*: In very old versions of MySQL (prior to 4.1), the *Note `TIMESTAMP': datetime. data type supported a display width, which was silenty ignored beginning with MySQL 4.1. This is deprecated in MySQL 5.1, and removed altogether in MySQL 5.5. These changes in behavior can lead to two problem scenarios when trying to use *Note `TIMESTAMP(N)': datetime. columns with a MySQL 5.5 or later server: * When importing a dump file (for example, one created using *Note `mysqldump': mysqldump.) created in a MySQL 5.0 or earlier server into a server from a newer release series, a *Note `CREATE TABLE': create-table. or *Note `ALTER TABLE': alter-table. statement containing *Note `TIMESTAMP(N)': datetime. causes the import to fail with a syntax error. To fix this problem, edit the dump file in a text editor to replace any instances of *Note `TIMESTAMP(N)': datetime. with *Note `TIMESTAMP': datetime. prior to importing the file. Be sure to use a plain text editor for this, and not a word processor; otherwise, the result is almost certain to be unusable for importing into the MySQL server. * When trying replicate any *Note `CREATE TABLE': create-table. or *Note `ALTER TABLE': alter-table. statement containing *Note `TIMESTAMP(N)': datetime. from a master MySQL server that supports the *Note `TIMESTAMP(N)': datetime. syntax to a MySQL 5.5.3 or newer slave, the statement causes replication to fail. Similarly, when you try to restore from a binary log written by a server that supports *Note `TIMESTAMP(N)': datetime. to a MySQL 5.5.3 or newer server, any *Note `CREATE TABLE': create-table. or *Note `ALTER TABLE': alter-table. statement containing *Note `TIMESTAMP(N)': datetime. causes the backup to fail. This holds true regardless of the logging format. It may be possible to fix such issues using a hex editor, by replacing any width arguments used with *Note `TIMESTAMP': datetime, and the parentheses containing them, with space characters (hexadecimal `20'). Be sure to use a programmer's binary hex editor and not a regular text editor or word processor for this; otherwise, the result is almost certain to be a corrupted binary log file. To guard against accidental corruption of the binary log, you should always work on a copy of the file rather than the original. You should try to handle potential issues of these types proactively by updating with *Note `ALTER TABLE': alter-table. any *Note `TIMESTAMP(N)': datetime. columns in your databases so that they use *Note `TIMESTAMP': datetime. instead, before performing any upgrades. * *Incompatible change*: For *Note `ENUM': enum. columns that had enumeration values containing commas, the commas were mapped to `0xff' internally. However, this rendered the commas indistinguishable from true `0xff' characters in the values. This no longer occurs. However, the fix requires that you dump and reload any tables that have *Note `ENUM': enum. columns containing true `0xff' in their values: Dump the tables using *Note `mysqldump': mysqldump. with the current server before upgrading from a version of MySQL 5.1 older than 5.1.15 to version 5.1.15 or newer. * As of MySQL 5.1.12, the `lc_time_names' system variable specifies the locale that controls the language used to display day and month names and abbreviations. This variable affects the output from the `DATE_FORMAT()', `DAYNAME()' and `MONTHNAME()' functions. See *Note locale-support::. * As of MySQL 5.1.9, *Note `mysqld_safe': mysqld-safe. no longer implicitly invokes `mysqld-max' if it exists. Instead, it invokes *Note `mysqld': mysqld. unless a `--mysqld' or `--mysqld-version' option is given to specify another server explicitly. If you previously relied on the implicit invocation of `mysqld-max', you should use an appropriate option now. As of MySQL 5.1.12, there is no longer any separate `mysqld-max' server, so no change should be necessary. * SQL Changes * * *Known issue*: Prior to MySQL 5.1.17, the parser accepted invalid code in SQL condition handlers, leading to server crashes or unexpected execution behavior in stored programs. Specifically, the parser permitted a condition handler to refer to labels for blocks that enclose the handler declaration. This was incorrect because block label scope does not include the code for handlers declared within the labeled block. As of 5.1.17, the parser rejects this invalid construct, but if you perform a binary upgrade (without dumping and reloading your databases), existing handlers that contain the construct still are invalid and should be rewritten _even if they appear to function as you expect._ To find affected handlers, use *Note `mysqldump': mysqldump. to dump all stored procedures and functions, triggers, and events. Then attempt to reload them into an upgraded server. Handlers that contain illegal label references will be rejected. For more information about condition handlers and writing them to avoid invalid jumps, see *Note declare-handler::. * *Incompatible change*: The parser accepted statements that contained `/* ... */' that were not properly closed with `*/', such as `SELECT 1 /* + 2'. As of MySQL 5.1.23, statements that contain unclosed `/*'-comments now are rejected with a syntax error. This fix has the potential to cause incompatibilities. Because of Bug#26302, which caused the trailing `*/' to be truncated from comments in views, stored routines, triggers, and events, it is possible that objects of those types may have been stored with definitions that now will be rejected as syntactically invalid. Such objects should be dropped and re-created so that their definitions do not contain truncated comments. * *Incompatible change*: Multiple-table *Note `DELETE': delete. statements containing ambiguous aliases could have unintended side effects such as deleting rows from the wrong table. Examples: DELETE FROM t1 AS a2 USING t1 AS a1 INNER JOIN t2 AS a2; DELETE t1 AS a2 FROM t1 AS a1 INNER JOIN t2 AS a2; To avoid ambiguity, declaration of aliases other than in the TABLE_REFERENCES part of the statement should be avoided: DELETE FROM t1 USING t1 AS a1 INNER JOIN t2 AS a2; DELETE t1 FROM t1 AS a1 INNER JOIN t2 AS a2; As of MySQL 5.1.23, alias declarations outside the TABLE_REFERENCES part of the statement are disallowed for the `USING' variant of multiple-table *Note `DELETE': delete. syntax. (In MySQL 5.5, alias declarations outside TABLE_REFERENCES are disallowed for all multiple-table *Note `DELETE': delete. statements.) Statements containing aliases that are no longer permitted must be rewritten. * *Incompatible change*: As of MySQL 5.1.8, `TYPE = ENGINE_NAME' is still accepted as a synonym for the `ENGINE = ENGINE_NAME' table option but generates a warning. You should note that this option is not available in MySQL 5.1.7, and *is removed altogether in MySQL 5.5 and produces a syntax error*. `TYPE' has been deprecated since MySQL 4.0. * *Incompatible change*: MySQL 5.1.6 introduces the `TRIGGER' privilege. Previously, the `SUPER' privilege was needed to create or drop triggers. Now those operations require the `TRIGGER' privilege. This is a security improvement because you no longer need to grant users the `SUPER' privilege to enable them to create triggers. However, the requirement that the account named in a trigger's `DEFINER' clause must have the `SUPER' privilege has changed to a requirement for the `TRIGGER' privilege. When upgrading from a previous version of MySQL 5.0 or 5.1 to MySQL 5.1.6 or newer, be sure to update your grant tables by running *Note `mysql_upgrade': mysql-upgrade. This will assign the `TRIGGER' privilege to all accounts that had the `SUPER' privilege. If you fail to update the grant tables, triggers may fail when activated. After updating the grant tables, you can revoke the `SUPER' privilege from those accounts that no longer otherwise require it. * Some keywords may be reserved in MySQL 5.1 that were not reserved in MySQL 5.0. See *Note reserved-words::. * The *Note `BACKUP TABLE': backup-table, and *Note `RESTORE TABLE': restore-table. statements are deprecated. *Note `mysqldump': mysqldump. or *Note `mysqlhotcopy': mysqlhotcopy. can be used as alternatives. * The *Note `LOAD DATA FROM MASTER': load-data-from-master. and *Note `LOAD TABLE FROM MASTER': load-table-from-master. statements are deprecated. See *Note load-data-from-master::, for recommended alternatives. * The *Note `INSTALL PLUGIN': install-plugin. and *Note `UNINSTALL PLUGIN': uninstall-plugin. statements that are used for the plugin API are new. So is the `WITH PARSER' clause for `FULLTEXT' index creation that associates a parser plugin with a full-text index. *Note plugin-api::. * C API Changes * * *Incompatible change*: As of MySQL 5.1.7, the *Note `mysql_stmt_attr_get()': mysql-stmt-attr-get. C API function returns a boolean rather than an unsigned int for `STMT_ATTR_UPDATE_MAX_LENGTH'. (Bug#16144)  File: manual.info, Node: downgrading, Next: checking-table-incompatibilities, Prev: upgrading, Up: upgrading-downgrading 3.13.2 Downgrading MySQL ------------------------ * Menu: * downgrading-to-previous-series:: Downgrading to MySQL 5.0 This section describes what you should do to downgrade to an older MySQL version in the unlikely case that the previous version worked better than the new one. If you are downgrading within the same release series (for example, from 5.0.13 to 5.0.12) the general rule is that you just have to install the new binaries on top of the old ones. There is no need to do anything with the databases. As always, however, it is always a good idea to make a backup. The following items form a checklist of things you should do whenever you perform a downgrade: * Read the upgrading section for the release series from which you are downgrading to be sure that it does not have any features you really need. See *Note upgrading::. * If there is a downgrading section for that version, you should read that as well. * To see which new features were added between the version to which you are downgrading and your current version, see the change logs (*Note news::). * Check *Note checking-table-incompatibilities::, to see whether changes to table formats or to character sets or collations were made between your current version of MySQL and the version to which you are downgrading. If so and these changes result in an incompatibility between MySQL versions, you will need to downgrade the affected tables using the instructions in *Note rebuilding-tables::. In most cases, you can move the MySQL format files and data files between different versions on the same architecture as long as you stay within versions for the same release series of MySQL. If you downgrade from one release series to another, there may be incompatibilities in table storage formats. In this case, use *Note `mysqldump': mysqldump. to dump your tables before downgrading. After downgrading, reload the dump file using *Note `mysql': mysql. or *Note `mysqlimport': mysqlimport. to re-create your tables. For examples, see *Note copying-databases::. A typical symptom of a downward-incompatible table format change when you downgrade is that you cannot open tables. In that case, use the following procedure: 1. Stop the older MySQL server that you are downgrading to. 2. Restart the newer MySQL server you are downgrading from. 3. Dump any tables that were inaccessible to the older server by using *Note `mysqldump': mysqldump. to create a dump file. 4. Stop the newer MySQL server and restart the older one. 5. Reload the dump file into the older server. Your tables should be accessible. It might also be the case that system tables in the `mysql' database have changed and that downgrading introduces some loss of functionality or requires some adjustments. Here are some examples: * Trigger creation requires the `TRIGGER' privilege as of MySQL 5.1. In MySQL 5.0, there is no `TRIGGER' privilege and `SUPER' is required instead. If you downgrade from MySQL 5.1 to 5.0, you will need to give the `SUPER' privilege to those accounts that had the `TRIGGER' privilege in 5.1. * Triggers were added in MySQL 5.0, so if you downgrade from 5.0 to 4.1, you cannot use triggers at all. * The `mysql.proc.comment' column definition changed between MySQL 5.1 and 5.5. After a downgrade from 5.5 to 5.1, this table is seen as corrupt and in need of repair. To workaround this problem, execute *Note `mysql_upgrade': mysql-upgrade. from the version of MySQL to which you downgraded.  File: manual.info, Node: downgrading-to-previous-series, Prev: downgrading, Up: downgrading 3.13.2.1 Downgrading to MySQL 5.0 ................................. When downgrading to MySQL 5.0 from MySQL 5.1, you should keep in mind the following issues relating to features found in MySQL 5.1, but not in MySQL 5.0: * Partitioning MySQL 5.0 does not support user-defined partitioning. If a table was created as a partitioned table in 5.1 (or if an table created in a previous version of MySQL was altered to include partitions after an upgrade to 5.1), the table is accessible after downgrade only if you do one of the following: * Export the table using *Note `mysqldump': mysqldump. and then drop it in MySQL 5.1; import the table again following the downgrade to MySQL 5.0. * Prior to the downgrade, remove the table's partitioning using `ALTER TABLE TABLE_NAME REMOVE PARTITIONING'. * Event Scheduler MySQL 5.0 does not support scheduled events. If your databases contain scheduled event definitions, you should prevent them from being dumped when you use *Note `mysqldump': mysqldump. by using the `--skip-events' option. (See *Note mysqldump::.) * Stored routines MySQL 5.1.21 added a number of new columns to the `mysql.proc' table in which stored routine definitions are stored. If you are downgrading from MySQL 5.1.21 or later to MySQL 5.0, you cannot import the MySQL 5.1 routine definitions into MySQL 5.0.46 or earlier using the dump of `mysql.proc' created by *Note `mysqldump': mysqldump. (such as when using the `--all-databases' option). Instead, you should run *Note `mysqldump `--routines'': mysqldump. prior to performing the downgrade and run the stored routines DDL statements following the downgrade. See Bug#11986, Bug#30029, and Bug#30660, for more information. * Triggers Trigger creation requires the `TRIGGER' privilege as of MySQL 5.1. In MySQL 5.0, there is no `TRIGGER' privilege and `SUPER' is required instead. If you downgrade from MySQL 5.1 to 5.0, you will need to give the `SUPER' privilege to those accounts that had the `TRIGGER' privilege in 5.1.  File: manual.info, Node: checking-table-incompatibilities, Next: rebuilding-tables, Prev: downgrading, Up: upgrading-downgrading 3.13.3 Checking Whether Tables or Indexes Must Be Rebuilt --------------------------------------------------------- A binary upgrade or downgrade is one that installs one version of MySQL `in place' over an existing version, without dumping and reloading tables: 1. Stop the server for the existing version if it is running. 2. Install a different version of MySQL. This is an upgrade if the new version is higher than the original version, a downgrade if the version is lower. 3. Start the server for the new version. In many cases, the tables from the previous version of MySQL can be used without problem by the new version. However, sometimes changes occur that require tables or table indexes to be rebuilt, as described in this section. If you have tables that are affected by any of the issues described here, rebuild the tables or indexes as necessary using the instructions given in *Note rebuilding-tables::. * Table Incompatibilities * After a binary upgrade to MySQL 5.1 from a MySQL 5.0 installation that contains *Note `ARCHIVE': archive-storage-engine. tables: * Before MySQL 5.1.42, accessing those tables will cause the server to crash, even if you have run *Note `mysql_upgrade': mysql-upgrade. or *Note `CHECK TABLE ... FOR UPGRADE': check-table. * As of MySQL 5.1.42, the server will not open 5.0 *Note `ARCHIVE': archive-storage-engine. tables at all. In either case, the solution is to use *Note `mysqldump': mysqldump. to dump all 5.0 *Note `ARCHIVE': archive-storage-engine. tables before upgrading, and reload them into MySQL 5.1 after upgrading. * Index Incompatibilities * If you perform a binary upgrade without dumping and reloading tables, you cannot upgrade directly from MySQL 4.1 to 5.1 or higher. This occurs due to an incompatible change in the `MyISAM' table index format in MySQL 5.0. Upgrade from MySQL 4.1 to 5.0 and repair all `MyISAM' tables. Then upgrade from MySQL 5.0 to 5.1 and check and repair your tables. Modifications to the handling of character sets or collations might change the character sort order, which causes the ordering of entries in any index that uses an affected character set or collation to be incorrect. Such changes result in several possible problems: * Comparison results that differ from previous results * Inability to find some index values due to misordered index entries * Misordered `ORDER BY' results * Tables that *Note `CHECK TABLE': check-table. reports as being in need of repair The solution to these problems is to rebuild any indexes that use an affected character set or collation, either by dropping and re-creating the indexes, or by dumping and reloading the entire table. For information about rebuilding indexes, see *Note rebuilding-tables::. To check whether a table has indexes that must be rebuilt, consult the following list. It indicates which versions of MySQL introduced character set or collation changes that require indexes to be rebuilt. Each entry indicates the version in which the change occurred and the character sets or collations that the change affects. If the change is associated with a particular bug report, the bug number is given. The list applies both for binary upgrades and downgrades. For example, Bug#27877 was fixed in MySQL 5.1.24 and 5.4.0, so it applies to upgrades from versions older than 5.1.24 to 5.1.24 or newer, and to downgrades from 5.1.24 or newer to versions older than 5.1.24. In many cases, you can use *Note `CHECK TABLE ... FOR UPGRADE': check-table. to identify tables for which index rebuilding is required. (It will report: `Table upgrade required. Please do "REPAIR TABLE `tbl_name`" or dump/reload to fix it!') In these cases, you can also use *Note `mysqlcheck --check-upgrade': mysqlcheck. or *Note `mysql_upgrade': mysql-upgrade, which execute *Note `CHECK TABLE': check-table. However, the use of *Note `CHECK TABLE': check-table. applies only after upgrades, not downgrades. Also, *Note `CHECK TABLE': check-table. is not applicable to all storage engines. For details about which storage engines *Note `CHECK TABLE': check-table. supports, see *Note check-table::. Changes that cause index rebuilding to be necessary: * MySQL 5.0.48, 5.1.21 (Bug#29461) Affects indexes for columns that use any of these character sets: `eucjpms', `euc_kr', `gb2312', `latin7', `macce', `ujis' Affected tables can be detected by *Note `CHECK TABLE ... FOR UPGRADE': check-table. as of MySQL 5.1.29, 5.4.0 (see Bug#39585). * MySQL 5.0.48, 5.1.23 (Bug#27562) Affects indexes that use the `ascii_general_ci' collation for columns that contain any of these characters: `'`'' GRAVE ACCENT, `'['' LEFT SQUARE BRACKET, `'\'' REVERSE SOLIDUS, `']'' RIGHT SQUARE BRACKET, `'~'' TILDE Affected tables can be detected by *Note `CHECK TABLE ... FOR UPGRADE': check-table. as of MySQL 5.1.29, 5.4.0 (see Bug#39585). * MySQL 5.1.24, 5.4.0 (Bug#27877) Affects indexes that use the `utf8_general_ci' or `ucs2_general_ci' collation for columns that contain `'ss'' LATIN SMALL LETTER SHARP S (German). Affected tables can be detected by *Note `CHECK TABLE ... FOR UPGRADE': check-table. as of MySQL 5.1.30, 5.4.0 (see Bug#40053).  File: manual.info, Node: rebuilding-tables, Next: copying-databases, Prev: checking-table-incompatibilities, Up: upgrading-downgrading 3.13.4 Rebuilding or Repairing Tables or Indexes ------------------------------------------------ This section describes how to rebuild a table. This can be necessitated by changes to MySQL such as how data types are handled or changes to character set handling. For example, an error in a collation might have been corrected, necessitating a table rebuild to update the indexes for character columns that use the collation. (For examples, see *Note checking-table-incompatibilities::.) It might also be that a table repair or upgrade should be done as indicated by a table check operation such as that performed by `CHECK TABLE', *Note `mysqlcheck': mysqlcheck, or *Note `mysql_upgrade': mysql-upgrade. Methods for rebuilding a table include dumping and reloading it, or using *Note `ALTER TABLE': alter-table. or *Note `REPAIR TABLE': repair-table. *Note*: If you are rebuilding tables because a different version of MySQL will not handle them after a binary (in-place) upgrade or downgrade, you must use the dump-and-reload method. Dump the tables _before_ upgrading or downgrading using your original version of MySQL. Then reload the tables _after_ upgrading or downgrading. If you use the dump-and-reload method of rebuilding tables only for the purpose of rebuilding indexes, you can perform the dump either before or after upgrading or downgrading. Reloading still must be done afterward. To rebuild a table by dumping and reloading it, use *Note `mysqldump': mysqldump. to create a dump file and *Note `mysql': mysql. to reload the file: shell> mysqldump DB_NAME t1 > dump.sql shell> mysql DB_NAME < dump.sql To rebuild all the tables in a single database, specify the database name without any following table name: shell> mysqldump DB_NAME > dump.sql shell> mysql DB_NAME < dump.sql To rebuild all tables in all databases, use the `--all-databases' option: shell> mysqldump --all-databases > dump.sql shell> mysql < dump.sql To rebuild a table with *Note `ALTER TABLE': alter-table, use a `null' alteration; that is, an *Note `ALTER TABLE': alter-table. statement that `changes' the table to use the storage engine that it already has. For example, if `t1' is a `MyISAM' table, use this statement: mysql> ALTER TABLE t1 ENGINE = MyISAM; If you are not sure which storage engine to specify in the *Note `ALTER TABLE': alter-table. statement, use *Note `SHOW CREATE TABLE': show-create-table. to display the table definition. If you must rebuild a table because a table checking operation indicates that the table is corrupt or needs an upgrade, you can use *Note `REPAIR TABLE': repair-table. if that statement supports the table's storage engine. For example, to repair a `MyISAM' table, use this statement: mysql> REPAIR TABLE t1; For storage engines such as `InnoDB' that *Note `REPAIR TABLE': repair-table. does not support, use *Note `mysqldump': mysqldump. to create a dump file and *Note `mysql': mysql. to reload the file, as described earlier. For specifics about which storage engines *Note `REPAIR TABLE': repair-table. supports, see *Note repair-table::. *Note `mysqlcheck --repair': mysqlcheck. provides command-line access to the *Note `REPAIR TABLE': repair-table. statement. This can be a more convenient means of repairing tables because you can use the `--databases' or `--all-databases' option to repair all tables in specific databases or all databases, respectively: shell> mysqlcheck --repair --databases DB_NAME ... shell> mysqlcheck --repair --all-databases  File: manual.info, Node: copying-databases, Prev: rebuilding-tables, Up: upgrading-downgrading 3.13.5 Copying MySQL Databases to Another Machine ------------------------------------------------- You can copy the `.frm', `.MYI', and `.MYD' files for `MyISAM' tables between different architectures that support the same floating-point format. (MySQL takes care of any byte-swapping issues.) See *Note myisam-storage-engine::. In cases where you need to transfer databases between different architectures, you can use *Note `mysqldump': mysqldump. to create a file containing SQL statements. You can then transfer the file to the other machine and feed it as input to the *Note `mysql': mysql. client. Use *Note `mysqldump --help': mysqldump. to see what options are available. The easiest (although not the fastest) way to move a database between two machines is to run the following commands on the machine on which the database is located: shell> mysqladmin -h 'OTHER_HOSTNAME' create DB_NAME shell> mysqldump DB_NAME | mysql -h 'OTHER_HOSTNAME' DB_NAME If you want to copy a database from a remote machine over a slow network, you can use these commands: shell> mysqladmin create DB_NAME shell> mysqldump -h 'OTHER_HOSTNAME' --compress DB_NAME | mysql DB_NAME You can also store the dump in a file, transfer the file to the target machine, and then load the file into the database there. For example, you can dump a database to a compressed file on the source machine like this: shell> mysqldump --quick DB_NAME | gzip > DB_NAME.gz Transfer the file containing the database contents to the target machine and run these commands there: shell> mysqladmin create DB_NAME shell> gunzip < DB_NAME.gz | mysql DB_NAME You can also use *Note `mysqldump': mysqldump. and *Note `mysqlimport': mysqlimport. to transfer the database. For large tables, this is much faster than simply using *Note `mysqldump': mysqldump. In the following commands, DUMPDIR represents the full path name of the directory you use to store the output from *Note `mysqldump': mysqldump. First, create the directory for the output files and dump the database: shell> mkdir DUMPDIR shell> mysqldump --tab=DUMPDIR DB_NAME Then transfer the files in the DUMPDIR directory to some corresponding directory on the target machine and load the files into MySQL there: shell> mysqladmin create DB_NAME # create database shell> cat DUMPDIR/*.sql | mysql DB_NAME # create tables in database shell> mysqlimport DB_NAME DUMPDIR/*.txt # load data into tables Do not forget to copy the `mysql' database because that is where the grant tables are stored. You might have to run commands as the MySQL `root' user on the new machine until you have the `mysql' database in place. After you import the `mysql' database on the new machine, execute *Note `mysqladmin flush-privileges': mysqladmin. so that the server reloads the grant table information.  File: manual.info, Node: environment-variables, Next: perl-support, Prev: upgrading-downgrading, Up: installing 3.14 Environment Variables ========================== This section lists all the environment variables that are used directly or indirectly by MySQL. Most of these can also be found in other places in this manual. Note that any options on the command line take precedence over values specified in option files and environment variables, and values in option files take precedence over values in environment variables. In many cases, it is preferable to use an option file instead of environment variables to modify the behavior of MySQL. See *Note option-files::. To set an environment variable within `sh', `ksh', `bash', or `zsh' shells you can use the following commands: shell> ENVVAR=VALUE shell> export ENVVAR The `export' is required if you want other sub-commands to inherit that value during execution. On more recent shells you can combine the export and setting processes, like this: shell> export set ENVVAR=VALUE For the `csh', or `tcsh' shells, use the `setenv' command: shell> setenv ENVVAR VALUE Within the Windows Command Prompt use the *Note `set': set. command to specify the value of a variable: shell> set ENVVAR=VALUE On Unix, Linux, Mac OS X, and Windows, the *Note `set': set. command without parameters will display the list of currently set variables. *MySQL Related Environment Variables* Variable Description `CXX' The name of your C++ compiler (for running `configure'). `CC' The name of your C compiler (for running `configure'). `CFLAGS' Flags for your C compiler (for running `configure'). `CXXFLAGS' Flags for your C++ compiler (for running `configure'). `DBI_USER' The default user name for Perl DBI. `DBI_TRACE' Trace options for Perl DBI. `HOME' The default path for the *Note `mysql': mysql. history file is `$HOME/.mysql_history'. `LD_RUN_PATH' Used to specify the location of `libmysqlclient.so'. `MYSQL_DEBUG' Debug trace options when debugging. `MYSQL_GROUP_SUFFIX'Option group suffix value (like specifying `--defaults-group-suffix'). `MYSQL_HISTFILE' The path to the *Note `mysql': mysql. history file. If this variable is set, its value overrides the default for `$HOME/.mysql_history'. `MYSQL_HOME' The path to the directory in which the server-specific `my.cnf' file resides (as of MySQL 5.0.3). `MYSQL_HOST' The default host name used by the *Note `mysql': mysql. command-line client. `MYSQL_PS1' The command prompt to use in the *Note `mysql': mysql. command-line client. `MYSQL_PWD' The default password when connecting to *Note `mysqld': mysqld. Note that using this is insecure. See *Note password-security-user::. `MYSQL_TCP_PORT' The default TCP/IP port number. `MYSQL_UNIX_PORT' The default Unix socket file name; used for connections to `localhost'. `PATH' Used by the shell to find MySQL programs. `TMPDIR' The directory where temporary files are created. `TZ' This should be set to your local time zone. See *Note timezone-problems::. `UMASK' The user-file creation mode when creating files. See note following table. `UMASK_DIR' The user-directory creation mode when creating directories. See note following table. `USER' The default user name on Windows and NetWare when connecting to *Note `mysqld': mysqld. For information about the *Note `mysql': mysql. history file, see *Note mysql-history-file::. The `UMASK' and `UMASK_DIR' variables, despite their names, are used as modes, not masks: * If `UMASK' is set, *Note `mysqld': mysqld. uses `($UMASK | 0600)' as the mode for file creation, so that newly created files have a mode in the range from 0600 to 0666 (all values octal). * If `UMASK_DIR' is set, *Note `mysqld': mysqld. uses `($UMASK_DIR | 0700)' as the base mode for directory creation, which then is AND-ed with `~(~$UMASK & 0666)', so that newly created directories have a mode in the range from 0700 to 0777 (all values octal). The AND operation may remove read and write permissions from the directory mode, but not execute permissions. MySQL assumes that the value for `UMASK' or `UMASK_DIR' is in octal if it starts with a zero.  File: manual.info, Node: perl-support, Prev: environment-variables, Up: installing 3.15 Perl Installation Notes ============================ * Menu: * perl-installation:: Installing Perl on Unix * activestate-perl:: Installing ActiveState Perl on Windows * perl-support-problems:: Problems Using the Perl `DBI'/`DBD' Interface The Perl `DBI' module provides a generic interface for database access. You can write a `DBI' script that works with many different database engines without change. To use `DBI', you must install the `DBI' module, as well as a DataBase Driver (DBD) module for each type of databas server you want to access. For MySQL, this driver is the `DBD::mysql' module. Perl, and the `DBD::MySQL' module for `DBI' must be installed if you want to run the MySQL benchmark scripts; see *Note mysql-benchmarks::. They are also required for the MySQL Cluster *Note `ndb_size.pl': mysql-cluster-programs-ndb-size-pl. utility; see *Note mysql-cluster-programs-ndb-size-pl::. *Note*: Perl support is not included with MySQL distributions. You can obtain the necessary modules from `http://search.cpan.org' for Unix, or by using the ActiveState `ppm' program on Windows. The following sections describe how to do this. The `DBI'/`DBD' interface requires Perl 5.6.0, and 5.6.1 or later is preferred. DBI _does not work_ if you have an older version of Perl. You should use `DBD::mysql' 4.009 or higher. Although earlier versions are available, they do not support the full functionality of MySQL 5.1.  File: manual.info, Node: perl-installation, Next: activestate-perl, Prev: perl-support, Up: perl-support 3.15.1 Installing Perl on Unix ------------------------------ MySQL Perl support requires that you have installed MySQL client programming support (libraries and header files). Most installation methods install the necessary files. If you install MySQL from RPM files on Linux, be sure to install the developer RPM as well. The client programs are in the client RPM, but client programming support is in the developer RPM. The files you need for Perl support can be obtained from the CPAN (Comprehensive Perl Archive Network) at `http://search.cpan.org'. The easiest way to install Perl modules on Unix is to use the `CPAN' module. For example: shell> perl -MCPAN -e shell cpan> install DBI cpan> install DBD::mysql The `DBD::mysql' installation runs a number of tests. These tests attempt to connect to the local MySQL server using the default user name and password. (The default user name is your login name on Unix, and `ODBC' on Windows. The default password is `no password.') If you cannot connect to the server with those values (for example, if your account has a password), the tests fail. You can use `force install DBD::mysql' to ignore the failed tests. `DBI' requires the `Data::Dumper' module. It may be installed; if not, you should install it before installing `DBI'. It is also possible to download the module distributions in the form of compressed `tar' archives and build the modules manually. For example, to unpack and build a DBI distribution, use a procedure such as this: 1. Unpack the distribution into the current directory: shell> gunzip < DBI-VERSION.tar.gz | tar xvf - This command creates a directory named `DBI-VERSION'. 2. Change location into the top-level directory of the unpacked distribution: shell> cd DBI-VERSION 3. Build the distribution and compile everything: shell> perl Makefile.PL shell> make shell> make test shell> make install The `make test' command is important because it verifies that the module is working. Note that when you run that command during the `DBD::mysql' installation to exercise the interface code, the MySQL server must be running or the test fails. It is a good idea to rebuild and reinstall the `DBD::mysql' distribution whenever you install a new release of MySQL. This ensures that the latest versions of the MySQL client libraries are installed correctly. If you do not have access rights to install Perl modules in the system directory or if you want to install local Perl modules, the following reference may be useful: `http://servers.digitaldaze.com/extensions/perl/modules.html#modules' Look under the heading `Installing New Modules that Require Locally Installed Modules.'  File: manual.info, Node: activestate-perl, Next: perl-support-problems, Prev: perl-installation, Up: perl-support 3.15.2 Installing ActiveState Perl on Windows --------------------------------------------- On Windows, you should do the following to install the MySQL `DBD' module with ActiveState Perl: 1. Get ActiveState Perl from `http://www.activestate.com/Products/ActivePerl/' and install it. 2. Open a console window. 3. If necessary, set the `HTTP_proxy' variable. For example, you might try a setting like this: C:\> set HTTP_proxy=my.proxy.com:3128 4. Start the PPM program: C:\> C:\perl\bin\ppm.pl 5. If you have not previously done so, install `DBI': ppm> install DBI 6. If this succeeds, run the following command: ppm> install DBD-mysql This procedure should work with ActiveState Perl 5.6 or newer. If you cannot get the procedure to work, you should install the MyODBC driver instead and connect to the MySQL server through ODBC: use DBI; $dbh= DBI->connect("DBI:ODBC:$dsn",$user,$password) || die "Got error $DBI::errstr when connecting to $dsn\n";  File: manual.info, Node: perl-support-problems, Prev: activestate-perl, Up: perl-support 3.15.3 Problems Using the Perl `DBI'/`DBD' Interface ---------------------------------------------------- If Perl reports that it cannot find the `../mysql/mysql.so' module, the problem is probably that Perl cannot locate the `libmysqlclient.so' shared library. You should be able to fix this problem by one of the following methods: * Copy `libmysqlclient.so' to the directory where your other shared libraries are located (probably `/usr/lib' or `/lib'). * Modify the `-L' options used to compile `DBD::mysql' to reflect the actual location of `libmysqlclient.so'. * On Linux, you can add the path name of the directory where `libmysqlclient.so' is located to the `/etc/ld.so.conf' file. * Add the path name of the directory where `libmysqlclient.so' is located to the `LD_RUN_PATH' environment variable. Some systems use `LD_LIBRARY_PATH' instead. Note that you may also need to modify the `-L' options if there are other libraries that the linker fails to find. For example, if the linker cannot find `libc' because it is in `/lib' and the link command specifies `-L/usr/lib', change the `-L' option to `-L/lib' or add `-L/lib' to the existing link command. If you get the following errors from `DBD::mysql', you are probably using `gcc' (or using an old binary compiled with `gcc'): /usr/bin/perl: can't resolve symbol '__moddi3' /usr/bin/perl: can't resolve symbol '__divdi3' Add `-L/usr/lib/gcc-lib/... -lgcc' to the link command when the `mysql.so' library gets built (check the output from `make' for `mysql.so' when you compile the Perl client). The `-L' option should specify the path name of the directory where `libgcc.a' is located on your system. Another cause of this problem may be that Perl and MySQL are not both compiled with `gcc'. In this case, you can solve the mismatch by compiling both with `gcc'. You may see the following error from `DBD::mysql' when you run the tests: t/00base............install_driver(mysql) failed: Can't load '../blib/arch/auto/DBD/mysql/mysql.so' for module DBD::mysql: ../blib/arch/auto/DBD/mysql/mysql.so: undefined symbol: uncompress at /usr/lib/perl5/5.00503/i586-linux/DynaLoader.pm line 169. This means that you need to include the `-lz' compression library on the link line. That can be done by changing the following line in the file `lib/DBD/mysql/Install.pm': $sysliblist .= " -lm"; Change that line to: $sysliblist .= " -lm -lz"; After this, you _must_ run `make realclean' and then proceed with the installation from the beginning.  File: manual.info, Node: tutorial, Next: programs, Prev: installing, Up: Top 4 Tutorial ********** * Menu: * connecting-disconnecting:: Connecting to and Disconnecting from the Server * entering-queries:: Entering Queries * database-use:: Creating and Using a Database * getting-information:: Getting Information About Databases and Tables * batch-mode:: Using `mysql' in Batch Mode * examples:: Examples of Common Queries * apache:: Using MySQL with Apache This chapter provides a tutorial introduction to MySQL by showing how to use the *Note `mysql': mysql. client program to create and use a simple database. *Note `mysql': mysql. (sometimes referred to as the `terminal monitor' or just `monitor') is an interactive program that enables you to connect to a MySQL server, run queries, and view the results. *Note `mysql': mysql. may also be used in batch mode: you place your queries in a file beforehand, then tell *Note `mysql': mysql. to execute the contents of the file. Both ways of using *Note `mysql': mysql. are covered here. To see a list of options provided by *Note `mysql': mysql, invoke it with the `--help' option: shell> mysql --help This chapter assumes that *Note `mysql': mysql. is installed on your machine and that a MySQL server is available to which you can connect. If this is not true, contact your MySQL administrator. (If _you_ are the administrator, you need to consult the relevant portions of this manual, such as *Note server-administration::.) This chapter describes the entire process of setting up and using a database. If you are interested only in accessing an existing database, you may want to skip over the sections that describe how to create the database and the tables it contains. Because this chapter is tutorial in nature, many details are necessarily omitted. Consult the relevant sections of the manual for more information on the topics covered here.  File: manual.info, Node: connecting-disconnecting, Next: entering-queries, Prev: tutorial, Up: tutorial 4.1 Connecting to and Disconnecting from the Server =================================================== To connect to the server, you will usually need to provide a MySQL user name when you invoke *Note `mysql': mysql. and, most likely, a password. If the server runs on a machine other than the one where you log in, you will also need to specify a host name. Contact your administrator to find out what connection parameters you should use to connect (that is, what host, user name, and password to use). Once you know the proper parameters, you should be able to connect like this: shell> mysql -h HOST -u USER -p Enter password: ******** `host' and `user' represent the host name where your MySQL server is running and the user name of your MySQL account. Substitute appropriate values for your setup. The `********' represents your password; enter it when *Note `mysql': mysql. displays the `Enter password:' prompt. If that works, you should see some introductory information followed by a `mysql>' prompt: shell> mysql -h HOST -u USER -p Enter password: ******** Welcome to the MySQL monitor. Commands end with ; or \g. Your MySQL connection id is 25338 to server version: 5.1.59-standard Type 'help;' or '\h' for help. Type '\c' to clear the buffer. mysql> The `mysql>' prompt tells you that *Note `mysql': mysql. is ready for you to enter commands. If you are logging in on the same machine that MySQL is running on, you can omit the host, and simply use the following: shell> mysql -u USER -p If, when you attempt to log in, you get an error message such as `ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/tmp/mysql.sock' (2)', it means that the MySQL server daemon (Unix) or service (Windows) is not running. Consult the administrator or see the section of *Note installing:: that is appropriate to your operating system. For help with other problems often encountered when trying to log in, see *Note common-errors::. Some MySQL installations permit users to connect as the anonymous (unnamed) user to the server running on the local host. If this is the case on your machine, you should be able to connect to that server by invoking *Note `mysql': mysql. without any options: shell> mysql After you have connected successfully, you can disconnect any time by typing `QUIT' (or `\q') at the `mysql>' prompt: mysql> QUIT Bye On Unix, you can also disconnect by pressing Control+D. Most examples in the following sections assume that you are connected to the server. They indicate this by the `mysql>' prompt.  File: manual.info, Node: entering-queries, Next: database-use, Prev: connecting-disconnecting, Up: tutorial 4.2 Entering Queries ==================== Make sure that you are connected to the server, as discussed in the previous section. Doing so does not in itself select any database to work with, but that is okay. At this point, it is more important to find out a little about how to issue queries than to jump right in creating tables, loading data into them, and retrieving data from them. This section describes the basic principles of entering commands, using several queries you can try out to familiarize yourself with how *Note `mysql': mysql. works. Here is a simple command that asks the server to tell you its version number and the current date. Type it in as shown here following the `mysql>' prompt and press Enter: mysql> SELECT VERSION(), CURRENT_DATE; +-----------------+--------------+ | VERSION() | CURRENT_DATE | +-----------------+--------------+ | 5.1.2-alpha-log | 2005-10-11 | +-----------------+--------------+ 1 row in set (0.01 sec) mysql> This query illustrates several things about *Note `mysql': mysql.: * A command normally consists of an SQL statement followed by a semicolon. (There are some exceptions where a semicolon may be omitted. `QUIT', mentioned earlier, is one of them. We'll get to others later.) * When you issue a command, *Note `mysql': mysql. sends it to the server for execution and displays the results, then prints another `mysql>' prompt to indicate that it is ready for another command. * *Note `mysql': mysql. displays query output in tabular form (rows and columns). The first row contains labels for the columns. The rows following are the query results. Normally, column labels are the names of the columns you fetch from database tables. If you're retrieving the value of an expression rather than a table column (as in the example just shown), *Note `mysql': mysql. labels the column using the expression itself. * *Note `mysql': mysql. shows how many rows were returned and how long the query took to execute, which gives you a rough idea of server performance. These values are imprecise because they represent wall clock time (not CPU or machine time), and because they are affected by factors such as server load and network latency. (For brevity, the `rows in set' line is sometimes not shown in the remaining examples in this chapter.) Keywords may be entered in any lettercase. The following queries are equivalent: mysql> SELECT VERSION(), CURRENT_DATE; mysql> select version(), current_date; mysql> SeLeCt vErSiOn(), current_DATE; Here is another query. It demonstrates that you can use *Note `mysql': mysql. as a simple calculator: mysql> SELECT SIN(PI()/4), (4+1)*5; +------------------+---------+ | SIN(PI()/4) | (4+1)*5 | +------------------+---------+ | 0.70710678118655 | 25 | +------------------+---------+ 1 row in set (0.02 sec) The queries shown thus far have been relatively short, single-line statements. You can even enter multiple statements on a single line. Just end each one with a semicolon: mysql> SELECT VERSION(); SELECT NOW(); +-----------------+ | VERSION() | +-----------------+ | 5.1.2-alpha-log | +-----------------+ 1 row in set (0.00 sec) +---------------------+ | NOW() | +---------------------+ | 2005-10-11 15:15:00 | +---------------------+ 1 row in set (0.00 sec) A command need not be given all on a single line, so lengthy commands that require several lines are not a problem. *Note `mysql': mysql. determines where your statement ends by looking for the terminating semicolon, not by looking for the end of the input line. (In other words, *Note `mysql': mysql. accepts free-format input: it collects input lines but does not execute them until it sees the semicolon.) Here is a simple multiple-line statement: mysql> SELECT -> USER() -> , -> CURRENT_DATE; +---------------+--------------+ | USER() | CURRENT_DATE | +---------------+--------------+ | jon@localhost | 2005-10-11 | +---------------+--------------+ In this example, notice how the prompt changes from `mysql>' to `->' after you enter the first line of a multiple-line query. This is how *Note `mysql': mysql. indicates that it has not yet seen a complete statement and is waiting for the rest. The prompt is your friend, because it provides valuable feedback. If you use that feedback, you can always be aware of what *Note `mysql': mysql. is waiting for. If you decide you do not want to execute a command that you are in the process of entering, cancel it by typing `\c': mysql> SELECT -> USER() -> \c mysql> Here, too, notice the prompt. It switches back to `mysql>' after you type `\c', providing feedback to indicate that *Note `mysql': mysql. is ready for a new command. The following table shows each of the prompts you may see and summarizes what they mean about the state that *Note `mysql': mysql. is in. Prompt Meaning `mysql>'Ready for new command. `->' Waiting for next line of multiple-line command. `'>' Waiting for next line, waiting for completion of a string that began with a single quote (``'''). `">' Waiting for next line, waiting for completion of a string that began with a double quote (``"''). ``>' Waiting for next line, waiting for completion of an identifier that began with a backtick (```''). `/*>' Waiting for next line, waiting for completion of a comment that began with `/*'. Multiple-line statements commonly occur by accident when you intend to issue a command on a single line, but forget the terminating semicolon. In this case, *Note `mysql': mysql. waits for more input: mysql> SELECT USER() -> If this happens to you (you think you've entered a statement but the only response is a `->' prompt), most likely *Note `mysql': mysql. is waiting for the semicolon. If you don't notice what the prompt is telling you, you might sit there for a while before realizing what you need to do. Enter a semicolon to complete the statement, and *Note `mysql': mysql. executes it: mysql> SELECT USER() -> ; +---------------+ | USER() | +---------------+ | jon@localhost | +---------------+ The `'>' and `">' prompts occur during string collection (another way of saying that MySQL is waiting for completion of a string). In MySQL, you can write strings surrounded by either ``''' or ``"'' characters (for example, `'hello'' or `"goodbye"'), and *Note `mysql': mysql. lets you enter strings that span multiple lines. When you see a `'>' or `">' prompt, it means that you have entered a line containing a string that begins with a ``''' or ``"'' quote character, but have not yet entered the matching quote that terminates the string. This often indicates that you have inadvertently left out a quote character. For example: mysql> SELECT * FROM my_table WHERE name = 'Smith AND age < 30; '> If you enter this *Note `SELECT': select. statement, then press `Enter' and wait for the result, nothing happens. Instead of wondering why this query takes so long, notice the clue provided by the `'>' prompt. It tells you that *Note `mysql': mysql. expects to see the rest of an unterminated string. (Do you see the error in the statement? The string `'Smith' is missing the second single quotation mark.) At this point, what do you do? The simplest thing is to cancel the command. However, you cannot just type `\c' in this case, because *Note `mysql': mysql. interprets it as part of the string that it is collecting. Instead, enter the closing quote character (so *Note `mysql': mysql. knows you've finished the string), then type `\c': mysql> SELECT * FROM my_table WHERE name = 'Smith AND age < 30; '> '\c mysql> The prompt changes back to `mysql>', indicating that *Note `mysql': mysql. is ready for a new command. The ``>' prompt is similar to the `'>' and `">' prompts, but indicates that you have begun but not completed a backtick-quoted identifier. It is important to know what the `'>', `">', and ``>' prompts signify, because if you mistakenly enter an unterminated string, any further lines you type appear to be ignored by *Note `mysql': mysql.--including a line containing `QUIT'. This can be quite confusing, especially if you do not know that you need to supply the terminating quote before you can cancel the current command.  File: manual.info, Node: database-use, Next: getting-information, Prev: entering-queries, Up: tutorial 4.3 Creating and Using a Database ================================= * Menu: * creating-database:: Creating and Selecting a Database * creating-tables:: Creating a Table * loading-tables:: Loading Data into a Table * retrieving-data:: Retrieving Information from a Table Once you know how to enter commands, you are ready to access a database. Suppose that you have several pets in your home (your menagerie) and you would like to keep track of various types of information about them. You can do so by creating tables to hold your data and loading them with the desired information. Then you can answer different sorts of questions about your animals by retrieving data from the tables. This section shows you how to perform the following operations: * Create a database * Create a table * Load data into the table * Retrieve data from the table in various ways * Use multiple tables The menagerie database is simple (deliberately), but it is not difficult to think of real-world situations in which a similar type of database might be used. For example, a database like this could be used by a farmer to keep track of livestock, or by a veterinarian to keep track of patient records. A menagerie distribution containing some of the queries and sample data used in the following sections can be obtained from the MySQL Web site. It is available in both compressed `tar' file and Zip formats at `http://dev.mysql.com/doc/'. Use the *Note `SHOW': show. statement to find out what databases currently exist on the server: mysql> SHOW DATABASES; +----------+ | Database | +----------+ | mysql | | test | | tmp | +----------+ The `mysql' database describes user access privileges. The `test' database often is available as a workspace for users to try things out. The list of databases displayed by the statement may be different on your machine; *Note `SHOW DATABASES': show-databases. does not show databases that you have no privileges for if you do not have the *Note `SHOW DATABASES': show-databases. privilege. See *Note show-databases::. If the `test' database exists, try to access it: mysql> USE test Database changed *Note `USE': use, like `QUIT', does not require a semicolon. (You can terminate such statements with a semicolon if you like; it does no harm.) The *Note `USE': use. statement is special in another way, too: it must be given on a single line. You can use the `test' database (if you have access to it) for the examples that follow, but anything you create in that database can be removed by anyone else with access to it. For this reason, you should probably ask your MySQL administrator for permission to use a database of your own. Suppose that you want to call yours `menagerie'. The administrator needs to execute a command like this: mysql> GRANT ALL ON menagerie.* TO 'your_mysql_name'@'your_client_host'; where `your_mysql_name' is the MySQL user name assigned to you and `your_client_host' is the host from which you connect to the server.  File: manual.info, Node: creating-database, Next: creating-tables, Prev: database-use, Up: database-use 4.3.1 Creating and Selecting a Database --------------------------------------- If the administrator creates your database for you when setting up your permissions, you can begin using it. Otherwise, you need to create it yourself: mysql> CREATE DATABASE menagerie; Under Unix, database names are case sensitive (unlike SQL keywords), so you must always refer to your database as `menagerie', not as `Menagerie', `MENAGERIE', or some other variant. This is also true for table names. (Under Windows, this restriction does not apply, although you must refer to databases and tables using the same lettercase throughout a given query. However, for a variety of reasons, the recommended best practice is always to use the same lettercase that was used when the database was created.) *Note*: If you get an error such as `ERROR 1044 (42000): Access denied for user 'monty'@'localhost' to database 'menagerie'' when attempting to create a database, this means that your user account does not have the necessary privileges to do so. Discuss this with the administrator or see *Note privilege-system::. Creating a database does not select it for use; you must do that explicitly. To make `menagerie' the current database, use this command: mysql> USE menagerie Database changed Your database needs to be created only once, but you must select it for use each time you begin a *Note `mysql': mysql. session. You can do this by issuing a *Note `USE': use. statement as shown in the example. Alternatively, you can select the database on the command line when you invoke *Note `mysql': mysql. Just specify its name after any connection parameters that you might need to provide. For example: shell> mysql -h HOST -u USER -p menagerie Enter password: ******** *Important*: `menagerie' in the command just shown is *not* your password. If you want to supply your password on the command line after the `-p' option, you must do so with no intervening space (for example, as `-pmypassword', not as `-p mypassword'). However, putting your password on the command line is not recommended, because doing so exposes it to snooping by other users logged in on your machine. *Note*: You can see at any time which database is currently selected using *Note `SELECT': select. `DATABASE()'.  File: manual.info, Node: creating-tables, Next: loading-tables, Prev: creating-database, Up: database-use 4.3.2 Creating a Table ---------------------- Creating the database is the easy part, but at this point it is empty, as *Note `SHOW TABLES': show-tables. tells you: mysql> SHOW TABLES; Empty set (0.00 sec) The harder part is deciding what the structure of your database should be: what tables you need and what columns should be in each of them. You want a table that contains a record for each of your pets. This can be called the `pet' table, and it should contain, as a bare minimum, each animal's name. Because the name by itself is not very interesting, the table should contain other information. For example, if more than one person in your family keeps pets, you might want to list each animal's owner. You might also want to record some basic descriptive information such as species and sex. How about age? That might be of interest, but it is not a good thing to store in a database. Age changes as time passes, which means you'd have to update your records often. Instead, it is better to store a fixed value such as date of birth. Then, whenever you need age, you can calculate it as the difference between the current date and the birth date. MySQL provides functions for doing date arithmetic, so this is not difficult. Storing birth date rather than age has other advantages, too: * You can use the database for tasks such as generating reminders for upcoming pet birthdays. (If you think this type of query is somewhat silly, note that it is the same question you might ask in the context of a business database to identify clients to whom you need to send out birthday greetings in the current week or month, for that computer-assisted personal touch.) * You can calculate age in relation to dates other than the current date. For example, if you store death date in the database, you can easily calculate how old a pet was when it died. You can probably think of other types of information that would be useful in the `pet' table, but the ones identified so far are sufficient: name, owner, species, sex, birth, and death. Use a *Note `CREATE TABLE': create-table. statement to specify the layout of your table: mysql> CREATE TABLE pet (name VARCHAR(20), owner VARCHAR(20), -> species VARCHAR(20), sex CHAR(1), birth DATE, death DATE); *Note `VARCHAR': char. is a good choice for the `name', `owner', and `species' columns because the column values vary in length. The lengths in those column definitions need not all be the same, and need not be `20'. You can normally pick any length from `1' to `65535', whatever seems most reasonable to you. If you make a poor choice and it turns out later that you need a longer field, MySQL provides an *Note `ALTER TABLE': alter-table. statement. Several types of values can be chosen to represent sex in animal records, such as `'m'' and `'f'', or perhaps `'male'' and `'female''. It is simplest to use the single characters `'m'' and `'f''. The use of the *Note `DATE': datetime. data type for the `birth' and `death' columns is a fairly obvious choice. Once you have created a table, *Note `SHOW TABLES': show-tables. should produce some output: mysql> SHOW TABLES; +---------------------+ | Tables in menagerie | +---------------------+ | pet | +---------------------+ To verify that your table was created the way you expected, use a *Note `DESCRIBE': describe. statement: mysql> DESCRIBE pet; +---------+-------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +---------+-------------+------+-----+---------+-------+ | name | varchar(20) | YES | | NULL | | | owner | varchar(20) | YES | | NULL | | | species | varchar(20) | YES | | NULL | | | sex | char(1) | YES | | NULL | | | birth | date | YES | | NULL | | | death | date | YES | | NULL | | +---------+-------------+------+-----+---------+-------+ You can use *Note `DESCRIBE': describe. any time, for example, if you forget the names of the columns in your table or what types they have. For more information about MySQL data types, see *Note data-types::.  File: manual.info, Node: loading-tables, Next: retrieving-data, Prev: creating-tables, Up: database-use 4.3.3 Loading Data into a Table ------------------------------- After creating your table, you need to populate it. The *Note `LOAD DATA': load-data. and *Note `INSERT': insert. statements are useful for this. Suppose that your pet records can be described as shown here. (Observe that MySQL expects dates in `'YYYY-MM-DD'' format; this may be different from what you are used to.) name owner species sex birth death Fluffy Harold cat f 1993-02-04 Claws Gwen cat m 1994-03-17 Buffy Harold dog f 1989-05-13 Fang Benny dog m 1990-08-27 Bowser Diane dog m 1979-08-31 1995-07-29 Chirpy Gwen bird f 1998-09-11 WhistlerGwen bird 1997-12-09 Slim Benny snake m 1996-04-29 Because you are beginning with an empty table, an easy way to populate it is to create a text file containing a row for each of your animals, then load the contents of the file into the table with a single statement. You could create a text file `pet.txt' containing one record per line, with values separated by tabs, and given in the order in which the columns were listed in the *Note `CREATE TABLE': create-table. statement. For missing values (such as unknown sexes or death dates for animals that are still living), you can use `NULL' values. To represent these in your text file, use `\N' (backslash, capital-N). For example, the record for Whistler the bird would look like this (where the whitespace between values is a single tab character): Whistler Gwen bird \N 1997-12-09 \N To load the text file `pet.txt' into the `pet' table, use this statement: mysql> LOAD DATA LOCAL INFILE '/path/pet.txt' INTO TABLE pet; If you created the file on Windows with an editor that uses `\r\n' as a line terminator, you should use this statement instead: mysql> LOAD DATA LOCAL INFILE '/path/pet.txt' INTO TABLE pet -> LINES TERMINATED BY '\r\n'; (On an Apple machine running OS X, you would likely want to use `LINES TERMINATED BY '\r''.) You can specify the column value separator and end of line marker explicitly in the *Note `LOAD DATA': load-data. statement if you wish, but the defaults are tab and linefeed. These are sufficient for the statement to read the file `pet.txt' properly. If the statement fails, it is likely that your MySQL installation does not have local file capability enabled by default. See *Note load-data-local::, for information on how to change this. When you want to add new records one at a time, the *Note `INSERT': insert. statement is useful. In its simplest form, you supply values for each column, in the order in which the columns were listed in the *Note `CREATE TABLE': create-table. statement. Suppose that Diane gets a new hamster named `Puffball.' You could add a new record using an *Note `INSERT': insert. statement like this: mysql> INSERT INTO pet -> VALUES ('Puffball','Diane','hamster','f','1999-03-30',NULL); String and date values are specified as quoted strings here. Also, with *Note `INSERT': insert, you can insert `NULL' directly to represent a missing value. You do not use `\N' like you do with *Note `LOAD DATA': load-data. From this example, you should be able to see that there would be a lot more typing involved to load your records initially using several *Note `INSERT': insert. statements rather than a single *Note `LOAD DATA': load-data. statement.  File: manual.info, Node: retrieving-data, Prev: loading-tables, Up: database-use 4.3.4 Retrieving Information from a Table ----------------------------------------- * Menu: * selecting-all:: Selecting All Data * selecting-rows:: Selecting Particular Rows * selecting-columns:: Selecting Particular Columns * sorting-rows:: Sorting Rows * date-calculations:: Date Calculations * working-with-null:: Working with `NULL' Values * pattern-matching:: Pattern Matching * counting-rows:: Counting Rows * multiple-tables:: Using More Than one Table The *Note `SELECT': select. statement is used to pull information from a table. The general form of the statement is: SELECT WHAT_TO_SELECT FROM WHICH_TABLE WHERE CONDITIONS_TO_SATISFY; WHAT_TO_SELECT indicates what you want to see. This can be a list of columns, or `*' to indicate `all columns.' WHICH_TABLE indicates the table from which you want to retrieve data. The `WHERE' clause is optional. If it is present, CONDITIONS_TO_SATISFY specifies one or more conditions that rows must satisfy to qualify for retrieval.  File: manual.info, Node: selecting-all, Next: selecting-rows, Prev: retrieving-data, Up: retrieving-data 4.3.4.1 Selecting All Data .......................... The simplest form of *Note `SELECT': select. retrieves everything from a table: mysql> SELECT * FROM pet; +----------+--------+---------+------+------------+------------+ | name | owner | species | sex | birth | death | +----------+--------+---------+------+------------+------------+ | Fluffy | Harold | cat | f | 1993-02-04 | NULL | | Claws | Gwen | cat | m | 1994-03-17 | NULL | | Buffy | Harold | dog | f | 1989-05-13 | NULL | | Fang | Benny | dog | m | 1990-08-27 | NULL | | Bowser | Diane | dog | m | 1979-08-31 | 1995-07-29 | | Chirpy | Gwen | bird | f | 1998-09-11 | NULL | | Whistler | Gwen | bird | NULL | 1997-12-09 | NULL | | Slim | Benny | snake | m | 1996-04-29 | NULL | | Puffball | Diane | hamster | f | 1999-03-30 | NULL | +----------+--------+---------+------+------------+------------+ This form of *Note `SELECT': select. is useful if you want to review your entire table, for example, after you've just loaded it with your initial data set. For example, you may happen to think that the birth date for Bowser doesn't seem quite right. Consulting your original pedigree papers, you find that the correct birth year should be 1989, not 1979. There are at least two ways to fix this: * Edit the file `pet.txt' to correct the error, then empty the table and reload it using *Note `DELETE': delete. and *Note `LOAD DATA': load-data.: mysql> DELETE FROM pet; mysql> LOAD DATA LOCAL INFILE 'pet.txt' INTO TABLE pet; However, if you do this, you must also re-enter the record for Puffball. * Fix only the erroneous record with an *Note `UPDATE': update. statement: mysql> UPDATE pet SET birth = '1989-08-31' WHERE name = 'Bowser'; The *Note `UPDATE': update. changes only the record in question and does not require you to reload the table.  File: manual.info, Node: selecting-rows, Next: selecting-columns, Prev: selecting-all, Up: retrieving-data 4.3.4.2 Selecting Particular Rows ................................. As shown in the preceding section, it is easy to retrieve an entire table. Just omit the `WHERE' clause from the *Note `SELECT': select. statement. But typically you don't want to see the entire table, particularly when it becomes large. Instead, you're usually more interested in answering a particular question, in which case you specify some constraints on the information you want. Let's look at some selection queries in terms of questions about your pets that they answer. You can select only particular rows from your table. For example, if you want to verify the change that you made to Bowser's birth date, select Bowser's record like this: mysql> SELECT * FROM pet WHERE name = 'Bowser'; +--------+-------+---------+------+------------+------------+ | name | owner | species | sex | birth | death | +--------+-------+---------+------+------------+------------+ | Bowser | Diane | dog | m | 1989-08-31 | 1995-07-29 | +--------+-------+---------+------+------------+------------+ The output confirms that the year is correctly recorded as 1989, not 1979. String comparisons normally are case-insensitive, so you can specify the name as `'bowser'', `'BOWSER'', and so forth. The query result is the same. You can specify conditions on any column, not just `name'. For example, if you want to know which animals were born during or after 1998, test the `birth' column: mysql> SELECT * FROM pet WHERE birth >= '1998-1-1'; +----------+-------+---------+------+------------+-------+ | name | owner | species | sex | birth | death | +----------+-------+---------+------+------------+-------+ | Chirpy | Gwen | bird | f | 1998-09-11 | NULL | | Puffball | Diane | hamster | f | 1999-03-30 | NULL | +----------+-------+---------+------+------------+-------+ You can combine conditions, for example, to locate female dogs: mysql> SELECT * FROM pet WHERE species = 'dog' AND sex = 'f'; +-------+--------+---------+------+------------+-------+ | name | owner | species | sex | birth | death | +-------+--------+---------+------+------------+-------+ | Buffy | Harold | dog | f | 1989-05-13 | NULL | +-------+--------+---------+------+------------+-------+ The preceding query uses the `AND' logical operator. There is also an `OR' operator: mysql> SELECT * FROM pet WHERE species = 'snake' OR species = 'bird'; +----------+-------+---------+------+------------+-------+ | name | owner | species | sex | birth | death | +----------+-------+---------+------+------------+-------+ | Chirpy | Gwen | bird | f | 1998-09-11 | NULL | | Whistler | Gwen | bird | NULL | 1997-12-09 | NULL | | Slim | Benny | snake | m | 1996-04-29 | NULL | +----------+-------+---------+------+------------+-------+ `AND' and `OR' may be intermixed, although `AND' has higher precedence than `OR'. If you use both operators, it is a good idea to use parentheses to indicate explicitly how conditions should be grouped: mysql> SELECT * FROM pet WHERE (species = 'cat' AND sex = 'm') -> OR (species = 'dog' AND sex = 'f'); +-------+--------+---------+------+------------+-------+ | name | owner | species | sex | birth | death | +-------+--------+---------+------+------------+-------+ | Claws | Gwen | cat | m | 1994-03-17 | NULL | | Buffy | Harold | dog | f | 1989-05-13 | NULL | +-------+--------+---------+------+------------+-------+  File: manual.info, Node: selecting-columns, Next: sorting-rows, Prev: selecting-rows, Up: retrieving-data 4.3.4.3 Selecting Particular Columns .................................... If you do not want to see entire rows from your table, just name the columns in which you are interested, separated by commas. For example, if you want to know when your animals were born, select the `name' and `birth' columns: mysql> SELECT name, birth FROM pet; +----------+------------+ | name | birth | +----------+------------+ | Fluffy | 1993-02-04 | | Claws | 1994-03-17 | | Buffy | 1989-05-13 | | Fang | 1990-08-27 | | Bowser | 1989-08-31 | | Chirpy | 1998-09-11 | | Whistler | 1997-12-09 | | Slim | 1996-04-29 | | Puffball | 1999-03-30 | +----------+------------+ To find out who owns pets, use this query: mysql> SELECT owner FROM pet; +--------+ | owner | +--------+ | Harold | | Gwen | | Harold | | Benny | | Diane | | Gwen | | Gwen | | Benny | | Diane | +--------+ Notice that the query simply retrieves the `owner' column from each record, and some of them appear more than once. To minimize the output, retrieve each unique output record just once by adding the keyword `DISTINCT': mysql> SELECT DISTINCT owner FROM pet; +--------+ | owner | +--------+ | Benny | | Diane | | Gwen | | Harold | +--------+ You can use a `WHERE' clause to combine row selection with column selection. For example, to get birth dates for dogs and cats only, use this query: mysql> SELECT name, species, birth FROM pet -> WHERE species = 'dog' OR species = 'cat'; +--------+---------+------------+ | name | species | birth | +--------+---------+------------+ | Fluffy | cat | 1993-02-04 | | Claws | cat | 1994-03-17 | | Buffy | dog | 1989-05-13 | | Fang | dog | 1990-08-27 | | Bowser | dog | 1989-08-31 | +--------+---------+------------+  File: manual.info, Node: sorting-rows, Next: date-calculations, Prev: selecting-columns, Up: retrieving-data 4.3.4.4 Sorting Rows .................... You may have noticed in the preceding examples that the result rows are displayed in no particular order. It is often easier to examine query output when the rows are sorted in some meaningful way. To sort a result, use an `ORDER BY' clause. Here are animal birthdays, sorted by date: mysql> SELECT name, birth FROM pet ORDER BY birth; +----------+------------+ | name | birth | +----------+------------+ | Buffy | 1989-05-13 | | Bowser | 1989-08-31 | | Fang | 1990-08-27 | | Fluffy | 1993-02-04 | | Claws | 1994-03-17 | | Slim | 1996-04-29 | | Whistler | 1997-12-09 | | Chirpy | 1998-09-11 | | Puffball | 1999-03-30 | +----------+------------+ On character type columns, sorting--like all other comparison operations--is normally performed in a case-insensitive fashion. This means that the order is undefined for columns that are identical except for their case. You can force a case-sensitive sort for a column by using `BINARY' like so: `ORDER BY BINARY COL_NAME'. The default sort order is ascending, with smallest values first. To sort in reverse (descending) order, add the `DESC' keyword to the name of the column you are sorting by: mysql> SELECT name, birth FROM pet ORDER BY birth DESC; +----------+------------+ | name | birth | +----------+------------+ | Puffball | 1999-03-30 | | Chirpy | 1998-09-11 | | Whistler | 1997-12-09 | | Slim | 1996-04-29 | | Claws | 1994-03-17 | | Fluffy | 1993-02-04 | | Fang | 1990-08-27 | | Bowser | 1989-08-31 | | Buffy | 1989-05-13 | +----------+------------+ You can sort on multiple columns, and you can sort different columns in different directions. For example, to sort by type of animal in ascending order, then by birth date within animal type in descending order (youngest animals first), use the following query: mysql> SELECT name, species, birth FROM pet -> ORDER BY species, birth DESC; +----------+---------+------------+ | name | species | birth | +----------+---------+------------+ | Chirpy | bird | 1998-09-11 | | Whistler | bird | 1997-12-09 | | Claws | cat | 1994-03-17 | | Fluffy | cat | 1993-02-04 | | Fang | dog | 1990-08-27 | | Bowser | dog | 1989-08-31 | | Buffy | dog | 1989-05-13 | | Puffball | hamster | 1999-03-30 | | Slim | snake | 1996-04-29 | +----------+---------+------------+ The `DESC' keyword applies only to the column name immediately preceding it (`birth'); it does not affect the `species' column sort order.  File: manual.info, Node: date-calculations, Next: working-with-null, Prev: sorting-rows, Up: retrieving-data 4.3.4.5 Date Calculations ......................... MySQL provides several functions that you can use to perform calculations on dates, for example, to calculate ages or extract parts of dates. To determine how many years old each of your pets is, compute the difference in the year part of the current date and the birth date, then subtract one if the current date occurs earlier in the calendar year than the birth date. The following query shows, for each pet, the birth date, the current date, and the age in years. mysql> SELECT name, birth, CURDATE(), -> (YEAR(CURDATE())-YEAR(birth)) -> - (RIGHT(CURDATE(),5) AS age -> FROM pet; +----------+------------+------------+------+ | name | birth | CURDATE() | age | +----------+------------+------------+------+ | Fluffy | 1993-02-04 | 2003-08-19 | 10 | | Claws | 1994-03-17 | 2003-08-19 | 9 | | Buffy | 1989-05-13 | 2003-08-19 | 14 | | Fang | 1990-08-27 | 2003-08-19 | 12 | | Bowser | 1989-08-31 | 2003-08-19 | 13 | | Chirpy | 1998-09-11 | 2003-08-19 | 4 | | Whistler | 1997-12-09 | 2003-08-19 | 5 | | Slim | 1996-04-29 | 2003-08-19 | 7 | | Puffball | 1999-03-30 | 2003-08-19 | 4 | +----------+------------+------------+------+ Here, `YEAR()' pulls out the year part of a date and `RIGHT()' pulls off the rightmost five characters that represent the `MM-DD' (calendar year) part of the date. The part of the expression that compares the `MM-DD' values evaluates to 1 or 0, which adjusts the year difference down a year if `CURDATE()' occurs earlier in the year than `birth'. The full expression is somewhat ungainly, so an _alias_ (`age') is used to make the output column label more meaningful. The query works, but the result could be scanned more easily if the rows were presented in some order. This can be done by adding an `ORDER BY name' clause to sort the output by name: mysql> SELECT name, birth, CURDATE(), -> (YEAR(CURDATE())-YEAR(birth)) -> - (RIGHT(CURDATE(),5) AS age -> FROM pet ORDER BY name; +----------+------------+------------+------+ | name | birth | CURDATE() | age | +----------+------------+------------+------+ | Bowser | 1989-08-31 | 2003-08-19 | 13 | | Buffy | 1989-05-13 | 2003-08-19 | 14 | | Chirpy | 1998-09-11 | 2003-08-19 | 4 | | Claws | 1994-03-17 | 2003-08-19 | 9 | | Fang | 1990-08-27 | 2003-08-19 | 12 | | Fluffy | 1993-02-04 | 2003-08-19 | 10 | | Puffball | 1999-03-30 | 2003-08-19 | 4 | | Slim | 1996-04-29 | 2003-08-19 | 7 | | Whistler | 1997-12-09 | 2003-08-19 | 5 | +----------+------------+------------+------+ To sort the output by `age' rather than `name', just use a different `ORDER BY' clause: mysql> SELECT name, birth, CURDATE(), -> (YEAR(CURDATE())-YEAR(birth)) -> - (RIGHT(CURDATE(),5) AS age -> FROM pet ORDER BY age; +----------+------------+------------+------+ | name | birth | CURDATE() | age | +----------+------------+------------+------+ | Chirpy | 1998-09-11 | 2003-08-19 | 4 | | Puffball | 1999-03-30 | 2003-08-19 | 4 | | Whistler | 1997-12-09 | 2003-08-19 | 5 | | Slim | 1996-04-29 | 2003-08-19 | 7 | | Claws | 1994-03-17 | 2003-08-19 | 9 | | Fluffy | 1993-02-04 | 2003-08-19 | 10 | | Fang | 1990-08-27 | 2003-08-19 | 12 | | Bowser | 1989-08-31 | 2003-08-19 | 13 | | Buffy | 1989-05-13 | 2003-08-19 | 14 | +----------+------------+------------+------+ A similar query can be used to determine age at death for animals that have died. You determine which animals these are by checking whether the `death' value is `NULL'. Then, for those with non-`NULL' values, compute the difference between the `death' and `birth' values: mysql> SELECT name, birth, death, -> (YEAR(death)-YEAR(birth)) - (RIGHT(death,5) AS age -> FROM pet WHERE death IS NOT NULL ORDER BY age; +--------+------------+------------+------+ | name | birth | death | age | +--------+------------+------------+------+ | Bowser | 1989-08-31 | 1995-07-29 | 5 | +--------+------------+------------+------+ The query uses `death IS NOT NULL' rather than `death <> NULL' because `NULL' is a special value that cannot be compared using the usual comparison operators. This is discussed later. See *Note working-with-null::. What if you want to know which animals have birthdays next month? For this type of calculation, year and day are irrelevant; you simply want to extract the month part of the `birth' column. MySQL provides several functions for extracting parts of dates, such as `YEAR()', `MONTH()', and `DAYOFMONTH()'. `MONTH()' is the appropriate function here. To see how it works, run a simple query that displays the value of both `birth' and `MONTH(birth)': mysql> SELECT name, birth, MONTH(birth) FROM pet; +----------+------------+--------------+ | name | birth | MONTH(birth) | +----------+------------+--------------+ | Fluffy | 1993-02-04 | 2 | | Claws | 1994-03-17 | 3 | | Buffy | 1989-05-13 | 5 | | Fang | 1990-08-27 | 8 | | Bowser | 1989-08-31 | 8 | | Chirpy | 1998-09-11 | 9 | | Whistler | 1997-12-09 | 12 | | Slim | 1996-04-29 | 4 | | Puffball | 1999-03-30 | 3 | +----------+------------+--------------+ Finding animals with birthdays in the upcoming month is also simple. Suppose that the current month is April. Then the month value is `4' and you can look for animals born in May (month `5') like this: mysql> SELECT name, birth FROM pet WHERE MONTH(birth) = 5; +-------+------------+ | name | birth | +-------+------------+ | Buffy | 1989-05-13 | +-------+------------+ There is a small complication if the current month is December. You cannot merely add one to the month number (`12') and look for animals born in month `13', because there is no such month. Instead, you look for animals born in January (month `1'). You can write the query so that it works no matter what the current month is, so that you do not have to use the number for a particular month. `DATE_ADD()' enables you to add a time interval to a given date. If you add a month to the value of `CURDATE()', then extract the month part with `MONTH()', the result produces the month in which to look for birthdays: mysql> SELECT name, birth FROM pet -> WHERE MONTH(birth) = MONTH(DATE_ADD(CURDATE(),INTERVAL 1 MONTH)); A different way to accomplish the same task is to add `1' to get the next month after the current one after using the modulo function (`MOD') to wrap the month value to `0' if it is currently `12': mysql> SELECT name, birth FROM pet -> WHERE MONTH(birth) = MOD(MONTH(CURDATE()), 12) + 1; `MONTH()' returns a number between `1' and `12'. And `MOD(something,12)' returns a number between `0' and `11'. So the addition has to be after the `MOD()', otherwise we would go from November (`11') to January (`1').  File: manual.info, Node: working-with-null, Next: pattern-matching, Prev: date-calculations, Up: retrieving-data 4.3.4.6 Working with `NULL' Values .................................. The `NULL' value can be surprising until you get used to it. Conceptually, `NULL' means `a missing unknown value' and it is treated somewhat differently from other values. To test for `NULL', you cannot use the arithmetic comparison operators such as `=', `<', or `<>'. To demonstrate this for yourself, try the following query: mysql> SELECT 1 = NULL, 1 <> NULL, 1 < NULL, 1 > NULL; +----------+-----------+----------+----------+ | 1 = NULL | 1 <> NULL | 1 < NULL | 1 > NULL | +----------+-----------+----------+----------+ | NULL | NULL | NULL | NULL | +----------+-----------+----------+----------+ Clearly you get no meaningful results from these comparisons. Use the `IS NULL' and `IS NOT NULL' operators instead: mysql> SELECT 1 IS NULL, 1 IS NOT NULL; +-----------+---------------+ | 1 IS NULL | 1 IS NOT NULL | +-----------+---------------+ | 0 | 1 | +-----------+---------------+ In MySQL, `0' or `NULL' means false and anything else means true. The default truth value from a boolean operation is `1'. This special treatment of `NULL' is why, in the previous section, it was necessary to determine which animals are no longer alive using `death IS NOT NULL' instead of `death <> NULL'. Two `NULL' values are regarded as equal in a `GROUP BY'. When doing an `ORDER BY', `NULL' values are presented first if you do `ORDER BY ... ASC' and last if you do `ORDER BY ... DESC'. A common error when working with `NULL' is to assume that it is not possible to insert a zero or an empty string into a column defined as `NOT NULL', but this is not the case. These are in fact values, whereas `NULL' means `not having a value.' You can test this easily enough by using `IS [NOT] NULL' as shown: mysql> SELECT 0 IS NULL, 0 IS NOT NULL, '' IS NULL, '' IS NOT NULL; +-----------+---------------+------------+----------------+ | 0 IS NULL | 0 IS NOT NULL | '' IS NULL | '' IS NOT NULL | +-----------+---------------+------------+----------------+ | 0 | 1 | 0 | 1 | +-----------+---------------+------------+----------------+ Thus it is entirely possible to insert a zero or empty string into a `NOT NULL' column, as these are in fact `NOT NULL'. See *Note problems-with-null::.  File: manual.info, Node: pattern-matching, Next: counting-rows, Prev: working-with-null, Up: retrieving-data 4.3.4.7 Pattern Matching ........................ MySQL provides standard SQL pattern matching as well as a form of pattern matching based on extended regular expressions similar to those used by Unix utilities such as `vi', `grep', and `sed'. SQL pattern matching enables you to use ``_'' to match any single character and ``%'' to match an arbitrary number of characters (including zero characters). In MySQL, SQL patterns are case-insensitive by default. Some examples are shown here. You do not use `=' or `<>' when you use SQL patterns; use the `LIKE' or `NOT LIKE' comparison operators instead. To find names beginning with ``b'': mysql> SELECT * FROM pet WHERE name LIKE 'b%'; +--------+--------+---------+------+------------+------------+ | name | owner | species | sex | birth | death | +--------+--------+---------+------+------------+------------+ | Buffy | Harold | dog | f | 1989-05-13 | NULL | | Bowser | Diane | dog | m | 1989-08-31 | 1995-07-29 | +--------+--------+---------+------+------------+------------+ To find names ending with ``fy'': mysql> SELECT * FROM pet WHERE name LIKE '%fy'; +--------+--------+---------+------+------------+-------+ | name | owner | species | sex | birth | death | +--------+--------+---------+------+------------+-------+ | Fluffy | Harold | cat | f | 1993-02-04 | NULL | | Buffy | Harold | dog | f | 1989-05-13 | NULL | +--------+--------+---------+------+------------+-------+ To find names containing a ``w'': mysql> SELECT * FROM pet WHERE name LIKE '%w%'; +----------+-------+---------+------+------------+------------+ | name | owner | species | sex | birth | death | +----------+-------+---------+------+------------+------------+ | Claws | Gwen | cat | m | 1994-03-17 | NULL | | Bowser | Diane | dog | m | 1989-08-31 | 1995-07-29 | | Whistler | Gwen | bird | NULL | 1997-12-09 | NULL | +----------+-------+---------+------+------------+------------+ To find names containing exactly five characters, use five instances of the ``_'' pattern character: mysql> SELECT * FROM pet WHERE name LIKE '_____'; +-------+--------+---------+------+------------+-------+ | name | owner | species | sex | birth | death | +-------+--------+---------+------+------------+-------+ | Claws | Gwen | cat | m | 1994-03-17 | NULL | | Buffy | Harold | dog | f | 1989-05-13 | NULL | +-------+--------+---------+------+------------+-------+ The other type of pattern matching provided by MySQL uses extended regular expressions. When you test for a match for this type of pattern, use the `REGEXP' and `NOT REGEXP' operators (or `RLIKE' and `NOT RLIKE', which are synonyms). The following list describes some characteristics of extended regular expressions: * ``.'' matches any single character. * A character class ``[...]'' matches any character within the brackets. For example, ``[abc]'' matches ``a'', ``b'', or ``c''. To name a range of characters, use a dash. ``[a-z]'' matches any letter, whereas ``[0-9]'' matches any digit. * ``*'' matches zero or more instances of the thing preceding it. For example, ``x*'' matches any number of ``x'' characters, ``[0-9]*'' matches any number of digits, and ``.*'' matches any number of anything. * A `REGEXP' pattern match succeeds if the pattern matches anywhere in the value being tested. (This differs from a `LIKE' pattern match, which succeeds only if the pattern matches the entire value.) * To anchor a pattern so that it must match the beginning or end of the value being tested, use ``^'' at the beginning or ``$'' at the end of the pattern. To demonstrate how extended regular expressions work, the `LIKE' queries shown previously are rewritten here to use `REGEXP'. To find names beginning with ``b'', use ``^'' to match the beginning of the name: mysql> SELECT * FROM pet WHERE name REGEXP '^b'; +--------+--------+---------+------+------------+------------+ | name | owner | species | sex | birth | death | +--------+--------+---------+------+------------+------------+ | Buffy | Harold | dog | f | 1989-05-13 | NULL | | Bowser | Diane | dog | m | 1989-08-31 | 1995-07-29 | +--------+--------+---------+------+------------+------------+ If you really want to force a `REGEXP' comparison to be case sensitive, use the `BINARY' keyword to make one of the strings a binary string. This query matches only lowercase ``b'' at the beginning of a name: mysql> SELECT * FROM pet WHERE name REGEXP BINARY '^b'; To find names ending with ``fy'', use ``$'' to match the end of the name: mysql> SELECT * FROM pet WHERE name REGEXP 'fy$'; +--------+--------+---------+------+------------+-------+ | name | owner | species | sex | birth | death | +--------+--------+---------+------+------------+-------+ | Fluffy | Harold | cat | f | 1993-02-04 | NULL | | Buffy | Harold | dog | f | 1989-05-13 | NULL | +--------+--------+---------+------+------------+-------+ To find names containing a ``w'', use this query: mysql> SELECT * FROM pet WHERE name REGEXP 'w'; +----------+-------+---------+------+------------+------------+ | name | owner | species | sex | birth | death | +----------+-------+---------+------+------------+------------+ | Claws | Gwen | cat | m | 1994-03-17 | NULL | | Bowser | Diane | dog | m | 1989-08-31 | 1995-07-29 | | Whistler | Gwen | bird | NULL | 1997-12-09 | NULL | +----------+-------+---------+------+------------+------------+ Because a regular expression pattern matches if it occurs anywhere in the value, it is not necessary in the previous query to put a wildcard on either side of the pattern to get it to match the entire value like it would be if you used an SQL pattern. To find names containing exactly five characters, use ``^'' and ``$'' to match the beginning and end of the name, and five instances of ``.'' in between: mysql> SELECT * FROM pet WHERE name REGEXP '^.....$'; +-------+--------+---------+------+------------+-------+ | name | owner | species | sex | birth | death | +-------+--------+---------+------+------------+-------+ | Claws | Gwen | cat | m | 1994-03-17 | NULL | | Buffy | Harold | dog | f | 1989-05-13 | NULL | +-------+--------+---------+------+------------+-------+ You could also write the previous query using the `{N}' (`repeat-N-times') operator: mysql> SELECT * FROM pet WHERE name REGEXP '^.{5}$'; +-------+--------+---------+------+------------+-------+ | name | owner | species | sex | birth | death | +-------+--------+---------+------+------------+-------+ | Claws | Gwen | cat | m | 1994-03-17 | NULL | | Buffy | Harold | dog | f | 1989-05-13 | NULL | +-------+--------+---------+------+------------+-------+ *Note regexp::, provides more information about the syntax for regular expressions.  File: manual.info, Node: counting-rows, Next: multiple-tables, Prev: pattern-matching, Up: retrieving-data 4.3.4.8 Counting Rows ..................... Databases are often used to answer the question, `How often does a certain type of data occur in a table?' For example, you might want to know how many pets you have, or how many pets each owner has, or you might want to perform various kinds of census operations on your animals. Counting the total number of animals you have is the same question as `How many rows are in the `pet' table?' because there is one record per pet. `COUNT(*)' counts the number of rows, so the query to count your animals looks like this: mysql> SELECT COUNT(*) FROM pet; +----------+ | COUNT(*) | +----------+ | 9 | +----------+ Earlier, you retrieved the names of the people who owned pets. You can use `COUNT()' if you want to find out how many pets each owner has: mysql> SELECT owner, COUNT(*) FROM pet GROUP BY owner; +--------+----------+ | owner | COUNT(*) | +--------+----------+ | Benny | 2 | | Diane | 2 | | Gwen | 3 | | Harold | 2 | +--------+----------+ The preceding query uses `GROUP BY' to group all records for each `owner'. The use of `COUNT()' in conjunction with `GROUP BY' is useful for characterizing your data under various groupings. The following examples show different ways to perform animal census operations. Number of animals per species: mysql> SELECT species, COUNT(*) FROM pet GROUP BY species; +---------+----------+ | species | COUNT(*) | +---------+----------+ | bird | 2 | | cat | 2 | | dog | 3 | | hamster | 1 | | snake | 1 | +---------+----------+ Number of animals per sex: mysql> SELECT sex, COUNT(*) FROM pet GROUP BY sex; +------+----------+ | sex | COUNT(*) | +------+----------+ | NULL | 1 | | f | 4 | | m | 4 | +------+----------+ (In this output, `NULL' indicates that the sex is unknown.) Number of animals per combination of species and sex: mysql> SELECT species, sex, COUNT(*) FROM pet GROUP BY species, sex; +---------+------+----------+ | species | sex | COUNT(*) | +---------+------+----------+ | bird | NULL | 1 | | bird | f | 1 | | cat | f | 1 | | cat | m | 1 | | dog | f | 1 | | dog | m | 2 | | hamster | f | 1 | | snake | m | 1 | +---------+------+----------+ You need not retrieve an entire table when you use `COUNT()'. For example, the previous query, when performed just on dogs and cats, looks like this: mysql> SELECT species, sex, COUNT(*) FROM pet -> WHERE species = 'dog' OR species = 'cat' -> GROUP BY species, sex; +---------+------+----------+ | species | sex | COUNT(*) | +---------+------+----------+ | cat | f | 1 | | cat | m | 1 | | dog | f | 1 | | dog | m | 2 | +---------+------+----------+ Or, if you wanted the number of animals per sex only for animals whose sex is known: mysql> SELECT species, sex, COUNT(*) FROM pet -> WHERE sex IS NOT NULL -> GROUP BY species, sex; +---------+------+----------+ | species | sex | COUNT(*) | +---------+------+----------+ | bird | f | 1 | | cat | f | 1 | | cat | m | 1 | | dog | f | 1 | | dog | m | 2 | | hamster | f | 1 | | snake | m | 1 | +---------+------+----------+ If you name columns to select in addition to the `COUNT()' value, a `GROUP BY' clause should be present that names those same columns. Otherwise, the following occurs: * If the `ONLY_FULL_GROUP_BY' SQL mode is enabled, an error occurs: mysql> SET sql_mode = 'ONLY_FULL_GROUP_BY'; Query OK, 0 rows affected (0.00 sec) mysql> SELECT owner, COUNT(*) FROM pet; ERROR 1140 (42000): Mixing of GROUP columns (MIN(),MAX(),COUNT()...) with no GROUP columns is illegal if there is no GROUP BY clause * If `ONLY_FULL_GROUP_BY' is not enabled, the query is processed by treating all rows as a single group, but the value selected for each named column is indeterminate. The server is free to select the value from any row: mysql> SET sql_mode = ''; Query OK, 0 rows affected (0.00 sec) mysql> SELECT owner, COUNT(*) FROM pet; +--------+----------+ | owner | COUNT(*) | +--------+----------+ | Harold | 8 | +--------+----------+ 1 row in set (0.00 sec) See also *Note group-by-hidden-columns::.  File: manual.info, Node: multiple-tables, Prev: counting-rows, Up: retrieving-data 4.3.4.9 Using More Than one Table ................................. The `pet' table keeps track of which pets you have. If you want to record other information about them, such as events in their lives like visits to the vet or when litters are born, you need another table. What should this table look like? It needs to contain the following information: * The pet name so that you know which animal each event pertains to. * A date so that you know when the event occurred. * A field to describe the event. * An event type field, if you want to be able to categorize events. Given these considerations, the *Note `CREATE TABLE': create-table. statement for the `event' table might look like this: mysql> CREATE TABLE event (name VARCHAR(20), date DATE, -> type VARCHAR(15), remark VARCHAR(255)); As with the `pet' table, it is easiest to load the initial records by creating a tab-delimited text file containing the following information. name date type remark Fluffy 1995-05-15 litter 4 kittens, 3 female, 1 male Buffy 1993-06-23 litter 5 puppies, 2 female, 3 male Buffy 1994-06-19 litter 3 puppies, 3 female Chirpy 1999-03-21 vet needed beak straightened Slim 1997-08-03 vet broken rib Bowser 1991-10-12 kennel Fang 1991-10-12 kennel Fang 1998-08-28 birthday Gave him a new chew toy Claws 1998-03-17 birthday Gave him a new flea collar Whistler 1998-12-09 birthday First birthday Load the records like this: mysql> LOAD DATA LOCAL INFILE 'event.txt' INTO TABLE event; Based on what you have learned from the queries that you have run on the `pet' table, you should be able to perform retrievals on the records in the `event' table; the principles are the same. But when is the `event' table by itself insufficient to answer questions you might ask? Suppose that you want to find out the ages at which each pet had its litters. We saw earlier how to calculate ages from two dates. The litter date of the mother is in the `event' table, but to calculate her age on that date you need her birth date, which is stored in the `pet' table. This means the query requires both tables: mysql> SELECT pet.name, -> (YEAR(date)-YEAR(birth)) - (RIGHT(date,5) remark -> FROM pet INNER JOIN event -> ON pet.name = event.name -> WHERE event.type = 'litter'; +--------+------+-----------------------------+ | name | age | remark | +--------+------+-----------------------------+ | Fluffy | 2 | 4 kittens, 3 female, 1 male | | Buffy | 4 | 5 puppies, 2 female, 3 male | | Buffy | 5 | 3 puppies, 3 female | +--------+------+-----------------------------+ There are several things to note about this query: * The `FROM' clause joins two tables because the query needs to pull information from both of them. * When combining (joining) information from multiple tables, you need to specify how records in one table can be matched to records in the other. This is easy because they both have a `name' column. The query uses an `ON' clause to match up records in the two tables based on the `name' values. The query uses an `INNER JOIN' to combine the tables. An `INNER JOIN' permits rows from either table to appear in the result if and only if both tables meet the conditions specified in the `ON' clause. In this example, the `ON' clause specifies that the `name' column in the `pet' table must match the `name' column in the `event' table. If a name appears in one table but not the other, the row will not appear in the result because the condition in the `ON' clause fails. * Because the `name' column occurs in both tables, you must be specific about which table you mean when referring to the column. This is done by prepending the table name to the column name. You need not have two different tables to perform a join. Sometimes it is useful to join a table to itself, if you want to compare records in a table to other records in that same table. For example, to find breeding pairs among your pets, you can join the `pet' table with itself to produce candidate pairs of males and females of like species: mysql> SELECT p1.name, p1.sex, p2.name, p2.sex, p1.species -> FROM pet AS p1 INNER JOIN pet AS p2 -> ON p1.species = p2.species AND p1.sex = 'f' AND p2.sex = 'm'; +--------+------+--------+------+---------+ | name | sex | name | sex | species | +--------+------+--------+------+---------+ | Fluffy | f | Claws | m | cat | | Buffy | f | Fang | m | dog | | Buffy | f | Bowser | m | dog | +--------+------+--------+------+---------+ In this query, we specify aliases for the table name to refer to the columns and keep straight which instance of the table each column reference is associated with.  File: manual.info, Node: getting-information, Next: batch-mode, Prev: database-use, Up: tutorial 4.4 Getting Information About Databases and Tables ================================================== What if you forget the name of a database or table, or what the structure of a given table is (for example, what its columns are called)? MySQL addresses this problem through several statements that provide information about the databases and tables it supports. You have previously seen *Note `SHOW DATABASES': show-databases, which lists the databases managed by the server. To find out which database is currently selected, use the `DATABASE()' function: mysql> SELECT DATABASE(); +------------+ | DATABASE() | +------------+ | menagerie | +------------+ If you have not yet selected any database, the result is `NULL'. To find out what tables the default database contains (for example, when you are not sure about the name of a table), use this command: mysql> SHOW TABLES; +---------------------+ | Tables_in_menagerie | +---------------------+ | event | | pet | +---------------------+ The name of the column in the output produced by this statement is always `Tables_in_DB_NAME', where DB_NAME is the name of the database. See *Note show-tables::, for more information. If you want to find out about the structure of a table, the *Note `DESCRIBE': describe. statement is useful; it displays information about each of a table's columns: mysql> DESCRIBE pet; +---------+-------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +---------+-------------+------+-----+---------+-------+ | name | varchar(20) | YES | | NULL | | | owner | varchar(20) | YES | | NULL | | | species | varchar(20) | YES | | NULL | | | sex | char(1) | YES | | NULL | | | birth | date | YES | | NULL | | | death | date | YES | | NULL | | +---------+-------------+------+-----+---------+-------+ `Field' indicates the column name, `Type' is the data type for the column, `NULL' indicates whether the column can contain `NULL' values, `Key' indicates whether the column is indexed, and `Default' specifies the column's default value. `Extra' displays special information about columns: If a column was created with the `AUTO_INCREMENT' option, the value will be `auto_increment' rather than empty. `DESC' is a short form of *Note `DESCRIBE': describe. See *Note describe::, for more information. You can obtain the *Note `CREATE TABLE': create-table. statement necessary to create an existing table using the *Note `SHOW CREATE TABLE': show-create-table. statement. See *Note show-create-table::. If you have indexes on a table, `SHOW INDEX FROM TBL_NAME' produces information about them. See *Note show-index::, for more about this statement.  File: manual.info, Node: batch-mode, Next: examples, Prev: getting-information, Up: tutorial 4.5 Using `mysql' in Batch Mode =============================== In the previous sections, you used *Note `mysql': mysql. interactively to enter queries and view the results. You can also run *Note `mysql': mysql. in batch mode. To do this, put the commands you want to run in a file, then tell *Note `mysql': mysql. to read its input from the file: shell> mysql < BATCH-FILE If you are running *Note `mysql': mysql. under Windows and have some special characters in the file that cause problems, you can do this: C:\> mysql -e "source BATCH-FILE" If you need to specify connection parameters on the command line, the command might look like this: shell> mysql -h HOST -u USER -p < BATCH-FILE Enter password: ******** When you use *Note `mysql': mysql. this way, you are creating a script file, then executing the script. If you want the script to continue even if some of the statements in it produce errors, you should use the `--force' command-line option. Why use a script? Here are a few reasons: * If you run a query repeatedly (say, every day or every week), making it a script enables you to avoid retyping it each time you execute it. * You can generate new queries from existing ones that are similar by copying and editing script files. * Batch mode can also be useful while you're developing a query, particularly for multiple-line commands or multiple-statement sequences of commands. If you make a mistake, you don't have to retype everything. Just edit your script to correct the error, then tell *Note `mysql': mysql. to execute it again. * If you have a query that produces a lot of output, you can run the output through a pager rather than watching it scroll off the top of your screen: shell> mysql < BATCH-FILE | more * You can catch the output in a file for further processing: shell> mysql < BATCH-FILE > mysql.out * You can distribute your script to other people so that they can also run the commands. * Some situations do not allow for interactive use, for example, when you run a query from a `cron' job. In this case, you must use batch mode. The default output format is different (more concise) when you run *Note `mysql': mysql. in batch mode than when you use it interactively. For example, the output of `SELECT DISTINCT species FROM pet' looks like this when *Note `mysql': mysql. is run interactively: +---------+ | species | +---------+ | bird | | cat | | dog | | hamster | | snake | +---------+ In batch mode, the output looks like this instead: species bird cat dog hamster snake If you want to get the interactive output format in batch mode, use `mysql -t'. To echo to the output the commands that are executed, use `mysql -vvv'. You can also use scripts from the *Note `mysql': mysql. prompt by using the `source' command or `\.' command: mysql> source FILENAME; mysql> \. FILENAME See *Note batch-commands::, for more information.  File: manual.info, Node: examples, Next: apache, Prev: batch-mode, Up: tutorial 4.6 Examples of Common Queries ============================== * Menu: * example-maximum-column:: The Maximum Value for a Column * example-maximum-row:: The Row Holding the Maximum of a Certain Column * example-maximum-column-group:: Maximum of Column per Group * example-maximum-column-group-row:: The Rows Holding the Group-wise Maximum of a Certain Column * example-user-variables:: Using User-Defined Variables * example-foreign-keys:: Using Foreign Keys * searching-on-two-keys:: Searching on Two Keys * calculating-days:: Calculating Visits Per Day * example-auto-increment:: Using `AUTO_INCREMENT' Here are examples of how to solve some common problems with MySQL. Some of the examples use the table `shop' to hold the price of each article (item number) for certain traders (dealers). Supposing that each trader has a single fixed price per article, then (`article', `dealer') is a primary key for the records. Start the command-line tool *Note `mysql': mysql. and select a database: shell> mysql YOUR-DATABASE-NAME (In most MySQL installations, you can use the database named `test'). You can create and populate the example table with these statements: CREATE TABLE shop ( article INT(4) UNSIGNED ZEROFILL DEFAULT '0000' NOT NULL, dealer CHAR(20) DEFAULT '' NOT NULL, price DOUBLE(16,2) DEFAULT '0.00' NOT NULL, PRIMARY KEY(article, dealer)); INSERT INTO shop VALUES (1,'A',3.45),(1,'B',3.99),(2,'A',10.99),(3,'B',1.45), (3,'C',1.69),(3,'D',1.25),(4,'D',19.95); After issuing the statements, the table should have the following contents: SELECT * FROM shop; +---------+--------+-------+ | article | dealer | price | +---------+--------+-------+ | 0001 | A | 3.45 | | 0001 | B | 3.99 | | 0002 | A | 10.99 | | 0003 | B | 1.45 | | 0003 | C | 1.69 | | 0003 | D | 1.25 | | 0004 | D | 19.95 | +---------+--------+-------+  File: manual.info, Node: example-maximum-column, Next: example-maximum-row, Prev: examples, Up: examples 4.6.1 The Maximum Value for a Column ------------------------------------ `What is the highest item number?' SELECT MAX(article) AS article FROM shop; +---------+ | article | +---------+ | 4 | +---------+  File: manual.info, Node: example-maximum-row, Next: example-maximum-column-group, Prev: example-maximum-column, Up: examples 4.6.2 The Row Holding the Maximum of a Certain Column ----------------------------------------------------- _Task: Find the number, dealer, and price of the most expensive article._ This is easily done with a subquery: SELECT article, dealer, price FROM shop WHERE price=(SELECT MAX(price) FROM shop); +---------+--------+-------+ | article | dealer | price | +---------+--------+-------+ | 0004 | D | 19.95 | +---------+--------+-------+ Other solutions are to use a `LEFT JOIN' or to sort all rows descending by price and get only the first row using the MySQL-specific `LIMIT' clause: SELECT s1.article, s1.dealer, s1.price FROM shop s1 LEFT JOIN shop s2 ON s1.price < s2.price WHERE s2.article IS NULL; SELECT article, dealer, price FROM shop ORDER BY price DESC LIMIT 1; *Note*: If there were several most expensive articles, each with a price of 19.95, the `LIMIT' solution would show only one of them.  File: manual.info, Node: example-maximum-column-group, Next: example-maximum-column-group-row, Prev: example-maximum-row, Up: examples 4.6.3 Maximum of Column per Group --------------------------------- _Task: Find the highest price per article._ SELECT article, MAX(price) AS price FROM shop GROUP BY article; +---------+-------+ | article | price | +---------+-------+ | 0001 | 3.99 | | 0002 | 10.99 | | 0003 | 1.69 | | 0004 | 19.95 | +---------+-------+  File: manual.info, Node: example-maximum-column-group-row, Next: example-user-variables, Prev: example-maximum-column-group, Up: examples 4.6.4 The Rows Holding the Group-wise Maximum of a Certain Column ----------------------------------------------------------------- _Task: For each article, find the dealer or dealers with the most expensive price._ This problem can be solved with a subquery like this one: SELECT article, dealer, price FROM shop s1 WHERE price=(SELECT MAX(s2.price) FROM shop s2 WHERE s1.article = s2.article); +---------+--------+-------+ | article | dealer | price | +---------+--------+-------+ | 0001 | B | 3.99 | | 0002 | A | 10.99 | | 0003 | C | 1.69 | | 0004 | D | 19.95 | +---------+--------+-------+ The preceding example uses a correlated subquery, which can be inefficient (see *Note correlated-subqueries::). Other possibilities for solving the problem are to use an uncorrelated subquery in the `FROM' clause or a `LEFT JOIN': SELECT s1.article, dealer, s1.price FROM shop s1 JOIN ( SELECT article, MAX(price) AS price FROM shop GROUP BY article) AS s2 ON s1.article = s2.article AND s1.price = s2.price; SELECT s1.article, s1.dealer, s1.price FROM shop s1 LEFT JOIN shop s2 ON s1.article = s2.article AND s1.price < s2.price WHERE s2.article IS NULL; The `LEFT JOIN' works on the basis that when `s1.price' is at its maximum value, there is no `s2.price' with a greater value and the `s2' rows values will be `NULL'. See *Note join::.  File: manual.info, Node: example-user-variables, Next: example-foreign-keys, Prev: example-maximum-column-group-row, Up: examples 4.6.5 Using User-Defined Variables ---------------------------------- You can employ MySQL user variables to remember results without having to store them in temporary variables in the client. (See *Note user-variables::.) For example, to find the articles with the highest and lowest price you can do this: mysql> SELECT @min_price:=MIN(price),@max_price:=MAX(price) FROM shop; mysql> SELECT * FROM shop WHERE price=@min_price OR price=@max_price; +---------+--------+-------+ | article | dealer | price | +---------+--------+-------+ | 0003 | D | 1.25 | | 0004 | D | 19.95 | +---------+--------+-------+ *Note*: It is also possible to store the name of a database object such as a table or a column in a user variable and then to use this variable in an SQL statement; however, this requires the use of a prepared statement. See *Note sql-syntax-prepared-statements::, for more information.  File: manual.info, Node: example-foreign-keys, Next: searching-on-two-keys, Prev: example-user-variables, Up: examples 4.6.6 Using Foreign Keys ------------------------ In MySQL, `InnoDB' tables support checking of foreign key constraints. See *Note innodb-storage-engine::, and *Note ansi-diff-foreign-keys::. A foreign key constraint is not required merely to join two tables. For storage engines other than `InnoDB', it is possible when defining a column to use a `REFERENCES TBL_NAME(COL_NAME)' clause, which has no actual effect, and _serves only as a memo or comment to you that the column which you are currently defining is intended to refer to a column in another table_. It is extremely important to realize when using this syntax that: * MySQL does not perform any sort of `CHECK' to make sure that COL_NAME actually exists in TBL_NAME (or even that TBL_NAME itself exists). * MySQL does not perform any sort of action on TBL_NAME such as deleting rows in response to actions taken on rows in the table which you are defining; in other words, this syntax induces no `ON DELETE' or `ON UPDATE' behavior whatsoever. (Although you can write an `ON DELETE' or `ON UPDATE' clause as part of the `REFERENCES' clause, it is also ignored.) * This syntax creates a _column_; it does *not* create any sort of index or key. You can use a column so created as a join column, as shown here: CREATE TABLE person ( id SMALLINT UNSIGNED NOT NULL AUTO_INCREMENT, name CHAR(60) NOT NULL, PRIMARY KEY (id) ); CREATE TABLE shirt ( id SMALLINT UNSIGNED NOT NULL AUTO_INCREMENT, style ENUM('t-shirt', 'polo', 'dress') NOT NULL, color ENUM('red', 'blue', 'orange', 'white', 'black') NOT NULL, owner SMALLINT UNSIGNED NOT NULL REFERENCES person(id), PRIMARY KEY (id) ); INSERT INTO person VALUES (NULL, 'Antonio Paz'); SELECT @last := LAST_INSERT_ID(); INSERT INTO shirt VALUES (NULL, 'polo', 'blue', @last), (NULL, 'dress', 'white', @last), (NULL, 't-shirt', 'blue', @last); INSERT INTO person VALUES (NULL, 'Lilliana Angelovska'); SELECT @last := LAST_INSERT_ID(); INSERT INTO shirt VALUES (NULL, 'dress', 'orange', @last), (NULL, 'polo', 'red', @last), (NULL, 'dress', 'blue', @last), (NULL, 't-shirt', 'white', @last); SELECT * FROM person; +----+---------------------+ | id | name | +----+---------------------+ | 1 | Antonio Paz | | 2 | Lilliana Angelovska | +----+---------------------+ SELECT * FROM shirt; +----+---------+--------+-------+ | id | style | color | owner | +----+---------+--------+-------+ | 1 | polo | blue | 1 | | 2 | dress | white | 1 | | 3 | t-shirt | blue | 1 | | 4 | dress | orange | 2 | | 5 | polo | red | 2 | | 6 | dress | blue | 2 | | 7 | t-shirt | white | 2 | +----+---------+--------+-------+ SELECT s.* FROM person p INNER JOIN shirt s ON s.owner = p.id WHERE p.name LIKE 'Lilliana%' AND s.color <> 'white'; +----+-------+--------+-------+ | id | style | color | owner | +----+-------+--------+-------+ | 4 | dress | orange | 2 | | 5 | polo | red | 2 | | 6 | dress | blue | 2 | +----+-------+--------+-------+ When used in this fashion, the `REFERENCES' clause is not displayed in the output of *Note `SHOW CREATE TABLE': show-create-table. or *Note `DESCRIBE': describe.: SHOW CREATE TABLE shirt\G *************************** 1. row *************************** Table: shirt Create Table: CREATE TABLE `shirt` ( `id` smallint(5) unsigned NOT NULL auto_increment, `style` enum('t-shirt','polo','dress') NOT NULL, `color` enum('red','blue','orange','white','black') NOT NULL, `owner` smallint(5) unsigned NOT NULL, PRIMARY KEY (`id`) ) ENGINE=MyISAM DEFAULT CHARSET=latin1 The use of `REFERENCES' in this way as a comment or `reminder' in a column definition works with `MyISAM' tables.  File: manual.info, Node: searching-on-two-keys, Next: calculating-days, Prev: example-foreign-keys, Up: examples 4.6.7 Searching on Two Keys --------------------------- An `OR' using a single key is well optimized, as is the handling of `AND'. The one tricky case is that of searching on two different keys combined with `OR': SELECT field1_index, field2_index FROM test_table WHERE field1_index = '1' OR field2_index = '1' This case is optimized. See *Note index-merge-optimization::. You can also solve the problem efficiently by using a *Note `UNION': union. that combines the output of two separate *Note `SELECT': select. statements. See *Note union::. Each *Note `SELECT': select. searches only one key and can be optimized: SELECT field1_index, field2_index FROM test_table WHERE field1_index = '1' UNION SELECT field1_index, field2_index FROM test_table WHERE field2_index = '1';  File: manual.info, Node: calculating-days, Next: example-auto-increment, Prev: searching-on-two-keys, Up: examples 4.6.8 Calculating Visits Per Day -------------------------------- The following example shows how you can use the bit group functions to calculate the number of days per month a user has visited a Web page. CREATE TABLE t1 (year YEAR(4), month INT(2) UNSIGNED ZEROFILL, day INT(2) UNSIGNED ZEROFILL); INSERT INTO t1 VALUES(2000,1,1),(2000,1,20),(2000,1,30),(2000,2,2), (2000,2,23),(2000,2,23); The example table contains year-month-day values representing visits by users to the page. To determine how many different days in each month these visits occur, use this query: SELECT year,month,BIT_COUNT(BIT_OR(1< ALTER TABLE tbl AUTO_INCREMENT = 100; More information about `AUTO_INCREMENT' is available here: * How to assign the `AUTO_INCREMENT' attribute to a column: *Note create-table::, and *Note alter-table::. * How `AUTO_INCREMENT' behaves depending on the `NO_AUTO_VALUE_ON_ZERO' SQL mode: *Note server-sql-mode::. * How to use the `LAST_INSERT_ID()' function to find the row that contains the most recent `AUTO_INCREMENT' value: *Note information-functions::. * Setting the `AUTO_INCREMENT' value to be used: *Note server-system-variables::. * `AUTO_INCREMENT' and replication: *Note replication-features-auto-increment::. * Server-system variables related to `AUTO_INCREMENT' (`auto_increment_increment' and `auto_increment_offset') that can be used for replication: *Note server-system-variables::.  File: manual.info, Node: apache, Prev: examples, Up: tutorial 4.7 Using MySQL with Apache =========================== There are programs that let you authenticate your users from a MySQL database and also let you write your log files into a MySQL table. You can change the Apache logging format to be easily readable by MySQL by putting the following into the Apache configuration file: LogFormat \ "\"%h\",%{%Y%m%d%H%M%S}t,%>s,\"%b\",\"%{Content-Type}o\", \ \"%U\",\"%{Referer}i\",\"%{User-Agent}i\"" To load a log file in that format into MySQL, you can use a statement something like this: LOAD DATA INFILE '/LOCAL/ACCESS_LOG' INTO TABLE TBL_NAME FIELDS TERMINATED BY ',' OPTIONALLY ENCLOSED BY '"' ESCAPED BY '\\' The named table should be created to have columns that correspond to those that the `LogFormat' line writes to the log file.  File: manual.info, Node: programs, Next: server-administration, Prev: tutorial, Up: Top 5 MySQL Programs **************** * Menu: * programs-overview:: Overview of MySQL Programs * programs-using:: Using MySQL Programs * programs-server:: MySQL Server and Server-Startup Programs * programs-installation:: MySQL Installation-Related Programs * programs-client:: MySQL Client Programs * programs-admin-utils:: MySQL Administrative and Utility Programs * programs-development:: MySQL Program Development Utilities * programs-miscellaneous:: Miscellaneous Programs This chapter provides a brief overview of the MySQL command-line programs provided by Oracle Corporation. It also discusses the general syntax for specifying options when you run these programs. Most programs have options that are specific to their own operation, but the option syntax is similar for all of them. Finally, the chapter provides more detailed descriptions of individual programs, including which options they recognize.  File: manual.info, Node: programs-overview, Next: programs-using, Prev: programs, Up: programs 5.1 Overview of MySQL Programs ============================== There are many different programs in a MySQL installation. This section provides a brief overview of them. Later sections provide a more detailed description of each one, with the exception of MySQL Cluster programs. Each program's description indicates its invocation syntax and the options that it supports. *Note mysql-cluster::, describes programs specific to MySQL Cluster. Most MySQL distributions include all of these programs, except for those programs that are platform-specific. (For example, the server startup scripts are not used on Windows.) The exception is that RPM distributions are more specialized. There is one RPM for the server, another for client programs, and so forth. If you appear to be missing one or more programs, see *Note installing::, for information on types of distributions and what they contain. It may be that you have a distribution that does not include all programs and you need to install an additional package. Each MySQL program takes many different options. Most programs provide a `--help' option that you can use to get a description of the program's different options. For example, try *Note `mysql --help': mysql. You can override default option values for MySQL programs by specifying options on the command line or in an option file. See *Note programs-using::, for general information on invoking programs and specifying program options. The MySQL server, *Note `mysqld': mysqld, is the main program that does most of the work in a MySQL installation. The server is accompanied by several related scripts that assist you in starting and stopping the server: * *Note `mysqld': mysqld. The SQL daemon (that is, the MySQL server). To use client programs, *Note `mysqld': mysqld. must be running, because clients gain access to databases by connecting to the server. See *Note mysqld::. * *Note `mysqld_safe': mysqld-safe. A server startup script. *Note `mysqld_safe': mysqld-safe. attempts to start *Note `mysqld': mysqld. See *Note mysqld-safe::. * *Note `mysql.server': mysql-server. A server startup script. This script is used on systems that use System V-style run directories containing scripts that start system services for particular run levels. It invokes *Note `mysqld_safe': mysqld-safe. to start the MySQL server. See *Note mysql-server::. * *Note `mysqld_multi': mysqld-multi. A server startup script that can start or stop multiple servers installed on the system. See *Note mysqld-multi::. An alternative to *Note `mysqld_multi': mysqld-multi. is `mysqlmanager', the MySQL Instance Manager. See *Note instance-manager::. There are several programs that perform setup operations during MySQL installation or upgrading: * *Note `comp_err': comp-err. This program is used during the MySQL build/installation process. It compiles error message files from the error source files. See *Note comp-err::. * `make_binary_distribution' This program makes a binary release of a compiled MySQL. This could be sent by FTP to `/pub/mysql/upload/' on `ftp.mysql.com' for the convenience of other MySQL users. * *Note `make_win_bin_dist': make-win-bin-dist. This program is used on Windows. It packages a MySQL distribution for installation after the source distribution has been built. See *Note make-win-bin-dist::. * *Note `mysql_fix_privilege_tables': mysql-fix-privilege-tables. This program is used after a MySQL upgrade operation. It updates the grant tables with any changes that have been made in newer versions of MySQL. See *Note mysql-fix-privilege-tables::. Note: As of MySQL 5.1.7, this program has been superseded by *Note `mysql_upgrade': mysql-upgrade. and should no longer be used. * *Note `mysql_install_db': mysql-install-db. This script creates the MySQL database and initializes the grant tables with default privileges. It is usually executed only once, when first installing MySQL on a system. See *Note mysql-install-db::, *Note unix-postinstallation::, and *Note mysql-install-db::. * *Note `mysql_secure_installation': mysql-secure-installation. This program enables you to improve the security of your MySQL installation. SQL. See *Note mysql-secure-installation::. * *Note `mysql_tzinfo_to_sql': mysql-tzinfo-to-sql. This program loads the time zone tables in the `mysql' database using the contents of the host system _zoneinfo_ database (the set of files describing time zones). SQL. See *Note mysql-tzinfo-to-sql::. * *Note `mysql_upgrade': mysql-upgrade. This program is used after a MySQL upgrade operation. It checks tables for incompatibilities and repairs them if necessary, and updates the grant tables with any changes that have been made in newer versions of MySQL. See *Note mysql-upgrade::. MySQL client programs: * *Note `mysql': mysql. The command-line tool for interactively entering SQL statements or executing them from a file in batch mode. See *Note mysql::. * *Note `mysqladmin': mysqladmin. A client that performs administrative operations, such as creating or dropping databases, reloading the grant tables, flushing tables to disk, and reopening log files. *Note `mysqladmin': mysqladmin. can also be used to retrieve version, process, and status information from the server. See *Note mysqladmin::. * *Note `mysqlcheck': mysqlcheck. A table-maintenance client that checks, repairs, analyzes, and optimizes tables. See *Note mysqlcheck::. * *Note `mysqldump': mysqldump. A client that dumps a MySQL database into a file as SQL, text, or XML. See *Note mysqldump::. * *Note `mysqlimport': mysqlimport. A client that imports text files into their respective tables using *Note `LOAD DATA INFILE': load-data. See *Note mysqlimport::. * *Note `mysqlshow': mysqlshow. A client that displays information about databases, tables, columns, and indexes. See *Note mysqlshow::. * *Note `mysqlslap': mysqlslap. A client that is designed to emulate client load for a MySQL server and report the timing of each stage. It works as if multiple clients are accessing the server. See *Note mysqlslap::. MySQL administrative and utility programs: * *Note `innochecksum': innochecksum. An offline `InnoDB' offline file checksum utility. See *Note innochecksum::. * *Note `myisam_ftdump': myisam-ftdump. A utility that displays information about full-text indexes in `MyISAM' tables. See *Note myisam-ftdump::. * *Note `myisamchk': myisamchk. A utility to describe, check, optimize, and repair `MyISAM' tables. See *Note myisamchk::. * *Note `myisamlog': myisamlog, `isamlog' A utility that processes the contents of a `MyISAM' log file. See *Note myisamlog::. * *Note `myisampack': myisampack. A utility that compresses `MyISAM' tables to produce smaller read-only tables. See *Note myisampack::. * *Note `mysqlaccess': mysqlaccess. A script that checks the access privileges for a host name, user name, and database combination. See *Note mysqlaccess::. * *Note `mysqlbinlog': mysqlbinlog. A utility for reading statements from a binary log. The log of executed statements contained in the binary log files can be used to help recover from a crash. See *Note mysqlbinlog::. * *Note `mysqldumpslow': mysqldumpslow. A utility to read and summarize the contents of a slow query log. See *Note mysqldumpslow::. * *Note `mysqlhotcopy': mysqlhotcopy. A utility that quickly makes backups of `MyISAM' tables while the server is running. See *Note mysqlhotcopy::. * `mysqlmanager' The MySQL Instance Manager, a program for monitoring and managing MySQL servers. See *Note instance-manager::. *Important*: MySQL Instance Manager has been deprecated and is removed in MySQL 5.5. * *Note `mysql_convert_table_format': mysql-convert-table-format. A utility that converts tables in a database to use a given storage engine. See *Note mysql-convert-table-format::. * *Note `mysql_find_rows': mysql-find-rows. A utility that reads files containing SQL statements (such as update logs) and extracts statements that match a given regular expression. See *Note mysql-find-rows::. * *Note `mysql_fix_extensions': mysql-fix-extensions. A utility that converts the extensions for `MyISAM' table files to lowercase. This can be useful after transferring the files from a system with case-insensitive file names to a system with case-sensitive file names. See *Note mysql-fix-extensions::. * *Note `mysql_setpermission': mysql-setpermission. A utility for interactively setting permissions in the MySQL grant tables. See *Note mysql-setpermission::. * *Note `mysql_waitpid': mysql-waitpid. A utility that kills the process with a given process ID. See *Note mysql-waitpid::. * *Note `mysql_zap': mysql-zap. A utility that kills processes that match a pattern. See *Note mysql-zap::. MySQL program-development utilities: * *Note `msql2mysql': msql2mysql. A shell script that converts `mSQL' programs to MySQL. It doesn't handle every case, but it gives a good start when converting. See *Note msql2mysql::. * *Note `mysql_config': mysql-config. A shell script that produces the option values needed when compiling MySQL programs. See *Note mysql-config::. * *Note `my_print_defaults': my-print-defaults. A utility that shows which options are present in option groups of option files. See *Note my-print-defaults::. * *Note `resolve_stack_dump': resolve-stack-dump. A utility program that resolves a numeric stack trace dump to symbols. See *Note resolve-stack-dump::. Miscellaneous utilities: * *Note `perror': perror. A utility that displays the meaning of system or MySQL error codes. See *Note perror::. * *Note `replace': replace-utility. A utility program that performs string replacement in the input text. See *Note replace-utility::. * *Note `resolveip': resolveip. A utility program that resolves a host name to an IP address or vice versa. See *Note resolveip::. Oracle Corporation also provides several GUI tools for administering and otherwise working with MySQL Server: * MySQL Workbench: This is the latest graphical tool for working with MySQL databases. * MySQL Administrator: This tool is used for administering MySQL servers, databases, tables, and user accounts. * MySQL Query Browser: This graphical tool is used for creating, executing, and optimizing queries on MySQL databases. * MySQL Migration Toolkit: This tool helps you migrate schemas and data from other relational database management systems for use with MySQL. These GUI programs are available at `http://dev.mysql.com/downloads/'. Each has its own manual that you can access at `http://dev.mysql.com/doc/'. MySQL client programs that communicate with the server using the MySQL client/server library use the following environment variables. Environment Meaning Variable `MYSQL_UNIX_PORT' The default Unix socket file; used for connections to `localhost' `MYSQL_TCP_PORT' The default port number; used for TCP/IP connections `MYSQL_PWD' The default password `MYSQL_DEBUG' Debug trace options when debugging `TMPDIR' The directory where temporary tables and files are created For a full list of environment variables used by MySQL programs, see *Note environment-variables::. Use of `MYSQL_PWD' is insecure. See *Note password-security-user::.  File: manual.info, Node: programs-using, Next: programs-server, Prev: programs-overview, Up: programs 5.2 Using MySQL Programs ======================== * Menu: * invoking-programs:: Invoking MySQL Programs * connecting:: Connecting to the MySQL Server * program-options:: Specifying Program Options * setting-environment-variables:: Setting Environment Variables  File: manual.info, Node: invoking-programs, Next: connecting, Prev: programs-using, Up: programs-using 5.2.1 Invoking MySQL Programs ----------------------------- To invoke a MySQL program from the command line (that is, from your shell or command prompt), enter the program name followed by any options or other arguments needed to instruct the program what you want it to do. The following commands show some sample program invocations. ``shell>'' represents the prompt for your command interpreter; it is not part of what you type. The particular prompt you see depends on your command interpreter. Typical prompts are `$' for `sh' or `bash', `%' for `csh' or `tcsh', and `C:\>' for the Windows `command.com' or `cmd.exe' command interpreters. shell> mysql --user=root test shell> mysqladmin extended-status variables shell> mysqlshow --help shell> mysqldump -u root personnel Arguments that begin with a single or double dash (``-'', ``--'') specify program options. Options typically indicate the type of connection a program should make to the server or affect its operational mode. Option syntax is described in *Note program-options::. Nonoption arguments (arguments with no leading dash) provide additional information to the program. For example, the *Note `mysql': mysql. program interprets the first nonoption argument as a database name, so the command `mysql --user=root test' indicates that you want to use the `test' database. Later sections that describe individual programs indicate which options a program supports and describe the meaning of any additional nonoption arguments. Some options are common to a number of programs. The most frequently used of these are the `--host' (or `-h'), `--user' (or `-u'), and `--password' (or `-p') options that specify connection parameters. They indicate the host where the MySQL server is running, and the user name and password of your MySQL account. All MySQL client programs understand these options; they enable you to specify which server to connect to and the account to use on that server. Other connection options are `--port' (or `-P') to specify a TCP/IP port number and `--socket' (or `-S') to specify a Unix socket file on Unix (or named pipe name on Windows). For more information on options that specify connection options, see *Note connecting::. You may find it necessary to invoke MySQL programs using the path name to the `bin' directory in which they are installed. This is likely to be the case if you get a `program not found' error whenever you attempt to run a MySQL program from any directory other than the `bin' directory. To make it more convenient to use MySQL, you can add the path name of the `bin' directory to your `PATH' environment variable setting. That enables you to run a program by typing only its name, not its entire path name. For example, if *Note `mysql': mysql. is installed in `/usr/local/mysql/bin', you can run the program by invoking it as *Note `mysql': mysql, and it is not necessary to invoke it as `/usr/local/mysql/bin/mysql'. Consult the documentation for your command interpreter for instructions on setting your `PATH' variable. The syntax for setting environment variables is interpreter-specific. (Some information is given in *Note setting-environment-variables::.) After modifying your `PATH' setting, open a new console window on Windows or log in again on Unix so that the setting goes into effect.  File: manual.info, Node: connecting, Next: program-options, Prev: invoking-programs, Up: programs-using 5.2.2 Connecting to the MySQL Server ------------------------------------ For a client program to be able to connect to the MySQL server, it must use the proper connection parameters, such as the name of the host where the server is running and the user name and password of your MySQL account. Each connection parameter has a default value, but you can override them as necessary using program options specified either on the command line or in an option file. The examples here use the *Note `mysql': mysql. client program, but the principles apply to other clients such as *Note `mysqldump': mysqldump, *Note `mysqladmin': mysqladmin, or *Note `mysqlshow': mysqlshow. This command invokes *Note `mysql': mysql. without specifying any connection parameters explicitly: shell> mysql Because there are no parameter options, the default values apply: * The default host name is `localhost'. On Unix, this has a special meaning, as described later. * The default user name is `ODBC' on Windows or your Unix login name on Unix. * No password is sent if neither `-p' nor `--password' is given. * For *Note `mysql': mysql, the first nonoption argument is taken as the name of the default database. If there is no such option, *Note `mysql': mysql. does not select a default database. To specify the host name and user name explicitly, as well as a password, supply appropriate options on the command line: shell> mysql --host=localhost --user=myname --password=mypass mydb shell> mysql -h localhost -u myname -pmypass mydb For password options, the password value is optional: * If you use a `-p' or `--password' option and specify the password value, there must be _no space_ between `-p' or `--password=' and the password following it. * If you use a `-p' or `--password' option but do not specify the password value, the client program prompts you to enter the password. The password is not displayed as you enter it. This is more secure than giving the password on the command line. Other users on your system may be able to see a password specified on the command line by executing a command such as `ps auxw'. See *Note password-security-user::. As just mentioned, including the password value on the command line can be a security risk. To avoid this problem, specify the `--password' or `-p' option without any following password value: shell> mysql --host=localhost --user=myname --password mydb shell> mysql -h localhost -u myname -p mydb When the password option has no password value, the client program prints a prompt and waits for you to enter the password. (In these examples, `mydb' is _not_ interpreted as a password because it is separated from the preceding password option by a space.) On some systems, the library routine that MySQL uses to prompt for a password automatically limits the password to eight characters. That is a problem with the system library, not with MySQL. Internally, MySQL does not have any limit for the length of the password. To work around the problem, change your MySQL password to a value that is eight or fewer characters long, or put your password in an option file. On Unix, MySQL programs treat the host name `localhost' specially, in a way that is likely different from what you expect compared to other network-based programs. For connections to `localhost', MySQL programs attempt to connect to the local server by using a Unix socket file. This occurs even if a `--port' or `-P' option is given to specify a port number. To ensure that the client makes a TCP/IP connection to the local server, use `--host' or `-h' to specify a host name value of `127.0.0.1', or the IP address or name of the local server. You can also specify the connection protocol explicitly, even for `localhost', by using the `--protocol=TCP' option. For example: shell> mysql --host=127.0.0.1 shell> mysql --protocol=TCP The `--protocol' option enables you to establish a particular type of connection even when the other options would normally default to some other protocol. On Windows, you can force a MySQL client to use a named-pipe connection by specifying the `--pipe' or `--protocol=PIPE' option, or by specifying `.' (period) as the host name. If named-pipe connections are not enabled, an error occurs. Use the `--socket' option to specify the name of the pipe if you do not want to use the default pipe name. Connections to remote servers always use TCP/IP. This command connects to the server running on `remote.example.com' using the default port number (3306): shell> mysql --host=remote.example.com To specify a port number explicitly, use the `--port' or `-P' option: shell> mysql --host=remote.example.com --port=13306 You can specify a port number for connections to a local server, too. However, as indicated previously, connections to `localhost' on Unix will use a socket file by default. You will need to force a TCP/IP connection as already described or any option that specifies a port number will be ignored. For this command, the program uses a socket file on Unix and the `--port' option is ignored: shell> mysql --port=13306 --host=localhost To cause the port number to be used, invoke the program in either of these ways: shell> mysql --port=13306 --host=127.0.0.1 shell> mysql --port=13306 --protocol=TCP The following list summarizes the options that can be used to control how client programs connect to the server: * `--host=HOST_NAME', `-h HOST_NAME' The host where the server is running. The default value is `localhost'. * `--password[=PASS_VAL]', `-p[PASS_VAL]' The password of the MySQL account. As described earlier, the password value is optional, but if given, there must be _no space_ between `-p' or `--password=' and the password following it. The default is to send no password. * `--pipe', `-W' On Windows, connect to the server using a named pipe. The server must be started with the `--enable-named-pipe' option to enable named-pipe connections. * `--port=PORT_NUM', `-P PORT_NUM' The port number to use for the connection, for connections made using TCP/IP. The default port number is 3306. * `--protocol={TCP|SOCKET|PIPE|MEMORY}' This option explicitly specifies a protocol to use for connecting to the server. It is useful when the other connection parameters normally would cause a protocol to be used other than the one you want. For example, connections on Unix to `localhost' are made using a Unix socket file by default: shell> mysql --host=localhost To force a TCP/IP connection to be used instead, specify a `--protocol' option: shell> mysql --host=localhost --protocol=TCP The following table shows the permissible `--protocol' option values and indicates the platforms on which each value may be used. The values are not case sensitive. `--protocol' Connection Protocol Permissible Value Operating Systems `TCP' TCP/IP connection to local or All remote server `SOCKET' Unix socket file connection to Unix only local server `PIPE' Named-pipe connection to local or Windows only remote server `MEMORY' Shared-memory connection to local Windows only server * `--shared-memory-base-name=NAME' On Windows, the shared-memory name to use, for connections made using shared memory to a local server. The default value is `MYSQL'. The shared-memory name is case sensitive. The server must be started with the `--shared-memory' option to enable shared-memory connections. * `--socket=FILE_NAME', `-S FILE_NAME' On Unix, the name of the Unix socket file to use, for connections made using a named pipe to a local server. The default Unix socket file name is `/tmp/mysql.sock'. On Windows, the name of the named pipe to use, for connections to a local server. The default Windows pipe name is `MySQL'. The pipe name is not case sensitive. The server must be started with the `--enable-named-pipe' option to enable named-pipe connections. * `--ssl*' Options that begin with `--ssl' are used for establishing a secure connection to the server using SSL, if the server is configured with SSL support. For details, see *Note ssl-options::. * `--user=USER_NAME', `-u USER_NAME' The user name of the MySQL account you want to use. The default user name is `ODBC' on Windows or your Unix login name on Unix. It is possible to specify different default values to be used when you make a connection so that you need not enter them on the command line each time you invoke a client program. This can be done in a couple of ways: * You can specify connection parameters in the `[client]' section of an option file. The relevant section of the file might look like this: [client] host=HOST_NAME user=USER_NAME password=YOUR_PASS *Note option-files::, discusses option files further. * You can specify some connection parameters using environment variables. The host can be specified for *Note `mysql': mysql. using `MYSQL_HOST'. The MySQL user name can be specified using `USER' (this is for Windows and NetWare only). The password can be specified using `MYSQL_PWD', although this is insecure; see *Note password-security-user::. For a list of variables, see *Note environment-variables::.  File: manual.info, Node: program-options, Next: setting-environment-variables, Prev: connecting, Up: programs-using 5.2.3 Specifying Program Options -------------------------------- * Menu: * command-line-options:: Using Options on the Command Line * option-modifiers:: Program Option Modifiers * option-files:: Using Option Files * program-variables:: Using Options to Set Program Variables * option-defaults-equals:: Option Defaults, Options Expecting Values, and the `=' Sign There are several ways to specify options for MySQL programs: * List the options on the command line following the program name. This is common for options that apply to a specific invocation of the program. * List the options in an option file that the program reads when it starts. This is common for options that you want the program to use each time it runs. * List the options in environment variables (see *Note setting-environment-variables::). This method is useful for options that you want to apply each time the program runs. In practice, option files are used more commonly for this purpose, but *Note multiple-unix-servers::, discusses one situation in which environment variables can be very helpful. It describes a handy technique that uses such variables to specify the TCP/IP port number and Unix socket file for the server and for client programs. Options are processed in order, so if an option is specified multiple times, the last occurrence takes precedence. The following command causes *Note `mysql': mysql. to connect to the server running on `localhost': shell> mysql -h example.com -h localhost If conflicting or related options are given, later options take precedence over earlier options. The following command runs *Note `mysql': mysql. in `no column names' mode: shell> mysql --column-names --skip-column-names MySQL programs determine which options are given first by examining environment variables, then by reading option files, and then by checking the command line. This means that environment variables have the lowest precedence and command-line options the highest. You can take advantage of the way that MySQL programs process options by specifying default option values for a program in an option file. That enables you to avoid typing them each time you run the program while enabling you to override the defaults if necessary by using command-line options. An option can be specified by writing it in full or as any unambiguous prefix. For example, the `--compress' option can be given to *Note `mysqldump': mysqldump. as `--compr', but not as `--comp' because the latter is ambiguous: shell> mysqldump --comp mysqldump: ambiguous option '--comp' (compatible, compress) Be aware that the use of option prefixes can cause problems in the event that new options are implemented for a program. A prefix that is unambiguous now might become ambiguous in the future.  File: manual.info, Node: command-line-options, Next: option-modifiers, Prev: program-options, Up: program-options 5.2.3.1 Using Options on the Command Line ......................................... Program options specified on the command line follow these rules: * Options are given after the command name. * An option argument begins with one dash or two dashes, depending on whether it is a short form or long form of the option name. Many options have both short and long forms. For example, `-?' and `--help' are the short and long forms of the option that instructs a MySQL program to display its help message. * Option names are case sensitive. `-v' and `-V' are both legal and have different meanings. (They are the corresponding short forms of the `--verbose' and `--version' options.) * Some options take a value following the option name. For example, `-h localhost' or `--host=localhost' indicate the MySQL server host to a client program. The option value tells the program the name of the host where the MySQL server is running. * For a long option that takes a value, separate the option name and the value by an ``='' sign. For a short option that takes a value, the option value can immediately follow the option letter, or there can be a space between: `-hlocalhost' and `-h localhost' are equivalent. An exception to this rule is the option for specifying your MySQL password. This option can be given in long form as `--password=PASS_VAL' or as `--password'. In the latter case (with no password value given), the program prompts you for the password. The password option also may be given in short form as `-pPASS_VAL' or as `-p'. However, for the short form, if the password value is given, it must follow the option letter with _no intervening space_. The reason for this is that if a space follows the option letter, the program has no way to tell whether a following argument is supposed to be the password value or some other kind of argument. Consequently, the following two commands have two completely different meanings: shell> mysql -ptest shell> mysql -p test The first command instructs *Note `mysql': mysql. to use a password value of `test', but specifies no default database. The second instructs *Note `mysql': mysql. to prompt for the password value and to use `test' as the default database. * Within option names, dash (``-'') and underscore (``_'') may be used interchangeably. For example, `--skip-grant-tables' and `--skip_grant_tables' are equivalent. (However, the leading dashes cannot be given as underscores.) * For options that take a numeric value, the value can be given with a suffix of `K', `M', or `G' (either uppercase or lowercase) to indicate a multiplier of 1024, 1024^2 or 1024^3. For example, the following command tells *Note `mysqladmin': mysqladmin. to ping the server 1024 times, sleeping 10 seconds between each ping: mysql> mysqladmin --count=1K --sleep=10 ping Option values that contain spaces must be quoted when given on the command line. For example, the `--execute' (or `-e') option can be used with *Note `mysql': mysql. to pass SQL statements to the server. When this option is used, *Note `mysql': mysql. executes the statements in the option value and exits. The statements must be enclosed by quotation marks. For example, you can use the following command to obtain a list of user accounts: mysql> mysql -u root -p --execute="SELECT User, Host FROM mysql.user" Enter password: ****** +------+-----------+ | User | Host | +------+-----------+ | | gigan | | root | gigan | | | localhost | | jon | localhost | | root | localhost | +------+-----------+ shell> Note that the long form (`--execute') is followed by an equal sign (`='). If you wish to use quoted values within a statement, you will either need to escape the inner quotation marks, or use a different type of quotation marks within the statement from those used to quote the statement itself. The capabilities of your command processor dictate your choices for whether you can use single or double quotation marks and the syntax for escaping quote characters. For example, if your command processor supports quoting with single or double quotation marks, you can use double quotation marks around the statement, and single quotation marks for any quoted values within the statement. Multiple SQL statements may be passed in the option value on the command line, separated by semicolons: shell> mysql -u root -p -e "SELECT VERSION();SELECT NOW()" Enter password: ****** +-----------------+ | VERSION() | +-----------------+ | 5.1.5-alpha-log | +-----------------+ +---------------------+ | NOW() | +---------------------+ | 2006-01-05 21:19:04 | +---------------------+ The `--execute' or `-e' option may also be used to pass commands in an analogous fashion to the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. management client for MySQL Cluster. See *Note mysql-cluster-install-shutdown-restart::, for an example.  File: manual.info, Node: option-modifiers, Next: option-files, Prev: command-line-options, Up: program-options 5.2.3.2 Program Option Modifiers ................................ Some options are `boolean' and control behavior that can be turned on or off. For example, the *Note `mysql': mysql. client supports a `--column-names' option that determines whether or not to display a row of column names at the beginning of query results. By default, this option is enabled. However, you may want to disable it in some instances, such as when sending the output of *Note `mysql': mysql. into another program that expects to see only data and not an initial header line. To disable column names, you can specify the option using any of these forms: --disable-column-names --skip-column-names --column-names=0 The `--disable' and `--skip' prefixes and the `=0' suffix all have the same effect: They turn the option off. The `enabled' form of the option may be specified in any of these ways: --column-names --enable-column-names --column-names=1 If an option is prefixed by `--loose', a program does not exit with an error if it does not recognize the option, but instead issues only a warning: shell> mysql --loose-no-such-option mysql: WARNING: unknown option '--no-such-option' The `--loose' prefix can be useful when you run programs from multiple installations of MySQL on the same machine and list options in an option file, An option that may not be recognized by all versions of a program can be given using the `--loose' prefix (or `loose' in an option file). Versions of the program that recognize the option process it normally, and versions that do not recognize it issue a warning and ignore it. *Note `mysqld': mysqld. enables a limit to be placed on how large client programs can set dynamic system variables. To do this, use a `--maximum' prefix with the variable name. For example, `--maximum-query_cache_size=4M' prevents any client from making the query cache size larger than 4MB.  File: manual.info, Node: option-files, Next: program-variables, Prev: option-modifiers, Up: program-options 5.2.3.3 Using Option Files .......................... * Menu: * option-file-options:: Command-Line Options that Affect Option-File Handling * option-files-preconfigured:: Preconfigured Option Files Most MySQL programs can read startup options from option files (also sometimes called configuration files). Option files provide a convenient way to specify commonly used options so that they need not be entered on the command line each time you run a program. For the MySQL server, MySQL provides a number of *Note preconfigured option files: option-files-preconfigured. To determine whether a program reads option files, invoke it with the `--help' option. (For *Note `mysqld': mysqld, use `--verbose' and `--help'.) If the program reads option files, the help message indicates which files it looks for and which option groups it recognizes. *Note*: Option files used with MySQL Cluster programs are covered in *Note mysql-cluster-configuration::. On Windows, MySQL programs read startup options from the following files, in the specified order (top items are used first). File Name Purpose `WINDIR\my.ini', Global options `WINDIR\my.cnf' `C:\my.ini', Global options `C:\my.cnf' `INSTALLDIR\my.ini', Global options `INSTALLDIR\my.cnf' `defaults-extra-file' The file specified with `--defaults-extra-file=PATH', if any WINDIR represents the location of your Windows directory. This is commonly `C:\WINDOWS'. You can determine its exact location from the value of the `WINDIR' environment variable using the following command: C:\> echo %WINDIR% INSTALLDIR represents the MySQL installation directory. This is typically `C:\PROGRAMDIR\MySQL\MySQL 5.1 Server' where PROGRAMDIR represents the programs directory (usually `Program Files' on English-language versions of Windows), when MySQL 5.1 has been installed using the installation and configuration wizards. See The Location of the my.ini File (http://dev.mysql.com/doc/refman/5.0/en/windows-config-wizard.html#mysql-config-wizard-file-location). On Unix, Linux and Mac OS X, MySQL programs read startup options from the following files, in the specified order (top items are used first). File Name Purpose `/etc/my.cnf' Global options `/etc/mysql/my.cnf' Global options (as of MySQL 5.1.15) `SYSCONFDIR/my.cnf' Global options `$MYSQL_HOME/my.cnf' Server-specific options `defaults-extra-file' The file specified with `--defaults-extra-file=PATH', if any `~/.my.cnf' User-specific options `~' represents the current user's home directory (the value of `$HOME'). SYSCONFDIR represents the directory specified with the `--sysconfdir' option to `configure' when MySQL was built. By default, this is the `etc' directory located under the compiled-in installation directory. This location is used as of MySQL 5.1.10. (From 5.1.10 to 5.1.22, it was read last, after `~/.my.cnf'.) `MYSQL_HOME' is an environment variable containing the path to the directory in which the server-specific `my.cnf' file resides. If `MYSQL_HOME' is not set and you start the server using the *Note `mysqld_safe': mysqld-safe. program, *Note `mysqld_safe': mysqld-safe. attempts to set `MYSQL_HOME' as follows: * Let BASEDIR and DATADIR represent the path names of the MySQL base directory and data directory, respectively. * If there is a `my.cnf' file in DATADIR but not in BASEDIR, *Note `mysqld_safe': mysqld-safe. sets `MYSQL_HOME' to DATADIR. * Otherwise, if `MYSQL_HOME' is not set and there is no `my.cnf' file in DATADIR, *Note `mysqld_safe': mysqld-safe. sets `MYSQL_HOME' to BASEDIR. In MySQL 5.1, use of DATADIR as the location for `my.cnf' is deprecated. Typically, DATADIR is `/usr/local/mysql/data' for a binary installation or `/usr/local/var' for a source installation. Note that this is the data directory location that was specified at configuration time, not the one specified with the `--datadir' option when *Note `mysqld': mysqld. starts. Use of `--datadir' at runtime has no effect on where the server looks for option files, because it looks for them before processing any options. MySQL looks for option files in the order just described and reads any that exist. If an option file that you want to use does not exist, create it with a plain text editor. If multiple instances of a given option are found, the last instance takes precedence. There is one exception: For *Note `mysqld': mysqld, the _first_ instance of the `--user' option is used as a security precaution, to prevent a user specified in an option file from being overridden on the command line. *Note*: On Unix platforms, MySQL ignores configuration files that are world-writable. This is intentional as a security measure. Any long option that may be given on the command line when running a MySQL program can be given in an option file as well. To get the list of available options for a program, run it with the `--help' option. The syntax for specifying options in an option file is similar to command-line syntax (see *Note command-line-options::). However, in an option file, you omit the leading two dashes from the option name and you specify only one option per line. For example, `--quick' and `--host=localhost' on the command line should be specified as `quick' and `host=localhost' on separate lines in an option file. To specify an option of the form `--loose-OPT_NAME' in an option file, write it as `loose-OPT_NAME'. Empty lines in option files are ignored. Nonempty lines can take any of the following forms: * `#COMMENT', `;COMMENT' Comment lines start with ``#'' or ``;''. A ``#'' comment can start in the middle of a line as well. * `[GROUP]' GROUP is the name of the program or group for which you want to set options. After a group line, any option-setting lines apply to the named group until the end of the option file or another group line is given. * `OPT_NAME' This is equivalent to `--OPT_NAME' on the command line. * `OPT_NAME=VALUE' This is equivalent to `--OPT_NAME=VALUE' on the command line. In an option file, you can have spaces around the ``='' character, something that is not true on the command line. You can optionally enclose the value within single quotation marks or double quotation marks, which is useful if the value contains a ``#'' comment character. Leading and trailing spaces are automatically deleted from option names and values. You can use the escape sequences ``\b'', ``\t'', ``\n'', ``\r'', ``\\'', and ``\s'' in option values to represent the backspace, tab, newline, carriage return, backslash, and space characters. The escaping rules in option files are: * If a backslash is followed by a valid escape sequence character, the sequence is converted to the character represented by the sequence. For example, ``\s'' is converted to a space. * If a backslash is not followed by a valid escape sequence character, it remains unchanged. For example, ``\S'' is retained as is. The preceding rules mean that a literal backslash can be given as ``\\'', or as ``\'' if it is not followed by a valid escape sequence character. The rules for escape sequences in option files differ slightly from the rules for escape sequences in string literals in SQL statements. In the latter context, if `X' is not a value escape sequence character, ``\X'' becomes `X' rather than ``\X''. See *Note string-syntax::. The escaping rules for option file values are especially pertinent for Windows path names, which use ``\'' as a path name separator. A separator in a Windows path name must be written as ``\\'' if it is followed by an escape sequence character. It can be written as ``\\'' or ``\'' if it is not. Alternatively, ``/'' may be used in Windows path names and will be treated as ``\''. Suppose that you want to specify a base directory of `C:\Program Files\MySQL\MySQL Server 5.1' in an option file. This can be done several ways. Some examples: basedir="C:\Program Files\MySQL\MySQL Server 5.1" basedir="C:\\Program Files\\MySQL\\MySQL Server 5.1" basedir="C:/Program Files/MySQL/MySQL Server 5.1" basedir=C:\\Program\sFiles\\MySQL\\MySQL\sServer\s5.1 If an option group name is the same as a program name, options in the group apply specifically to that program. For example, the `[mysqld]' and `[mysql]' groups apply to the *Note `mysqld': mysqld. server and the *Note `mysql': mysql. client program, respectively. The `[client]' option group is read by all client programs (but _not_ by *Note `mysqld': mysqld.). This enables you to specify options that apply to all clients. For example, `[client]' is the perfect group to use to specify the password that you use to connect to the server. (But make sure that the option file is readable and writable only by yourself, so that other people cannot find out your password.) Be sure not to put an option in the `[client]' group unless it is recognized by _all_ client programs that you use. Programs that do not understand the option quit after displaying an error message if you try to run them. Here is a typical global option file: [client] port=3306 socket=/tmp/mysql.sock [mysqld] port=3306 socket=/tmp/mysql.sock key_buffer_size=16M max_allowed_packet=8M [mysqldump] quick The preceding option file uses `VAR_NAME=VALUE' syntax for the lines that set the `key_buffer_size' and `max_allowed_packet' variables. Here is a typical user option file: [client] # The following password will be sent to all standard MySQL clients password="my_password" [mysql] no-auto-rehash connect_timeout=2 [mysqlhotcopy] interactive-timeout If you want to create option groups that should be read by *Note `mysqld': mysqld. servers from a specific MySQL release series only, you can do this by using groups with names of `[mysqld-5.0]', `[mysqld-5.1]', and so forth. The following group indicates that the `--new' option should be used only by MySQL servers with 5.1.x version numbers: [mysqld-5.1] new It is possible to use `!include' directives in option files to include other option files and `!includedir' to search specific directories for option files. For example, to include the `/home/mydir/myopt.cnf' file, use the following directive: !include /home/mydir/myopt.cnf To search the `/home/mydir' directory and read option files found there, use this directive: !includedir /home/mydir There is no guarantee about the order in which the option files in the directory will be read. *Note*: Currently, any files to be found and included using the `!includedir' directive on Unix operating systems _must_ have file names ending in `.cnf'. On Windows, this directive checks for files with the `.ini' or `.cnf' extension. Write the contents of an included option file like any other option file. That is, it should contain groups of options, each preceded by a `[GROUP]' line that indicates the program to which the options apply. While an included file is being processed, only those options in groups that the current program is looking for are used. Other groups are ignored. Suppose that a `my.cnf' file contains this line: !include /home/mydir/myopt.cnf And suppose that `/home/mydir/myopt.cnf' looks like this: [mysqladmin] force [mysqld] key_buffer_size=16M If `my.cnf' is processed by *Note `mysqld': mysqld, only the `[mysqld]' group in `/home/mydir/myopt.cnf' is used. If the file is processed by *Note `mysqladmin': mysqladmin, only the `[mysqladmin]' group is used. If the file is processed by any other program, no options in `/home/mydir/myopt.cnf' are used. The `!includedir' directive is processed similarly except that all option files in the named directory are read.  File: manual.info, Node: option-file-options, Next: option-files-preconfigured, Prev: option-files, Up: option-files 5.2.3.4 Command-Line Options that Affect Option-File Handling ............................................................. Most MySQL programs that support option files handle the following options. They affect option-file handling, so they must be given on the command line and not in an option file. To work properly, each of these options must immediately follow the command name, with these exceptions: * `--print-defaults' may be used immediately after `--defaults-file' or `--defaults-extra-file'. * On Windows, if the `--defaults-file' and `--install' options are given, `--install' option must be first. See *Note windows-start-service::. When specifying file names, you should avoid the use of the ``~'' shell metacharacter because it might not be interpreted as you expect. * `--defaults-extra-file=FILE_NAME' Read this option file after the global option file but (on Unix) before the user option file. If the file does not exist or is otherwise inaccessible, the program exits with an error. FILE_NAME is the full path name to the file. * `--defaults-file=FILE_NAME' Use only the given option file. If the file does not exist or is otherwise inaccessible, the program exits with an error. FILE_NAME is the full path name to the file. * `--defaults-group-suffix=STR' If this option is given, the program reads not only its usual option groups, but also groups with the usual names and a suffix of STR. For example, the *Note `mysql': mysql. client normally reads the `[client]' and `[mysql]' groups. If the `--defaults-group-suffix=_other' option is given, *Note `mysql': mysql. also reads the `[client_other]' and `[mysql_other]' groups. * `--no-defaults' Do not read any option files. If a program does not start because it is reading unknown options from an option file, `--no-defaults' can be used to prevent the program from reading them. * `--print-defaults' Print the program name and all options that it gets from option files.  File: manual.info, Node: option-files-preconfigured, Prev: option-file-options, Up: option-files 5.2.3.5 Preconfigured Option Files .................................. MySQL provides a number of preconfigured option files that can be used as a basis for tuning the MySQL server. Look for files such as `my-small.cnf', `my-medium.cnf', `my-large.cnf', and `my-huge.cnf', which are sample option files for small, medium, large, and very large systems. On Windows, the extension is `.ini' rather than `.cnf'. *Note*: On Windows, the `.ini' or `.cnf' option file extension might not be displayed. For a binary distribution, look for the files in or under your installation directory. If you have a source distribution, look in the `support-files' directory. You can rename a copy of a sample file and place it in the appropriate location for use as a base configuration file. Regarding names and appropriate location, see the general information provided in *Note option-files::.  File: manual.info, Node: program-variables, Next: option-defaults-equals, Prev: option-files, Up: program-options 5.2.3.6 Using Options to Set Program Variables .............................................. Many MySQL programs have internal variables that can be set at runtime using the *Note `SET': set-option. statement. See *Note set-option::, and *Note using-system-variables::. Most of these program variables also can be set at server startup by using the same syntax that applies to specifying program options. For example, *Note `mysql': mysql. has a `max_allowed_packet' variable that controls the maximum size of its communication buffer. To set the `max_allowed_packet' variable for *Note `mysql': mysql. to a value of 16MB, use either of the following commands: shell> mysql --max_allowed_packet=16777216 shell> mysql --max_allowed_packet=16M The first command specifies the value in bytes. The second specifies the value in megabytes. For variables that take a numeric value, the value can be given with a suffix of `K', `M', or `G' (either uppercase or lowercase) to indicate a multiplier of 1024, 1024^2 or 1024^3. (For example, when used to set `max_allowed_packet', the suffixes indicate units of kilobytes, megabytes, or gigabytes.) In an option file, variable settings are given without the leading dashes: [mysql] max_allowed_packet=16777216 Or: [mysql] max_allowed_packet=16M If you like, underscores in a variable name can be specified as dashes. The following option groups are equivalent. Both set the size of the server's key buffer to 512MB: [mysqld] key_buffer_size=512M [mysqld] key-buffer-size=512M A variable can be specified by writing it in full or as any unambiguous prefix. For example, the `max_allowed_packet' variable can be set for *Note `mysql': mysql. as `--max_a', but not as `--max' because the latter is ambiguous: shell> mysql --max=1000000 mysql: ambiguous option '--max=1000000' (max_allowed_packet, max_join_size) Be aware that the use of variable prefixes can cause problems in the event that new variables are implemented for a program. A prefix that is unambiguous now might become ambiguous in the future. Suffixes for specifying a value multiplier can be used when setting a variable at server startup, but not to set the value with *Note `SET': set-option. at runtime. On the other hand, with *Note `SET': set-option. you can assign a variable's value using an expression, which is not true when you set a variable at server startup. For example, the first of the following lines is legal at server startup, but the second is not: shell> mysql --max_allowed_packet=16M shell> mysql --max_allowed_packet=16*1024*1024 Conversely, the second of the following lines is legal at runtime, but the first is not: mysql> SET GLOBAL max_allowed_packet=16M; mysql> SET GLOBAL max_allowed_packet=16*1024*1024; *Note*: Before MySQL 4.0.2, the only syntax for setting program variables was `--set-variable=OPTION=VALUE' (or `set-variable=OPTION=VALUE' in option files). Underscores cannot be given as dashes, and the variable name must be specified in full. This syntax still is recognized, but is deprecated and is removed in MySQL 5.5.  File: manual.info, Node: option-defaults-equals, Prev: program-variables, Up: program-options 5.2.3.7 Option Defaults, Options Expecting Values, and the `=' Sign ................................................................... By convention, long forms of options that assign a value are written with an equals (`=') sign, like this: shell> mysql --host=tonfisk --user=jon For options that require a value (that is, not having a default value), the equal sign is not required, and so the following is also valid: shell> mysql --host tonfisk --user jon In both cases, the *Note `mysql': mysql. client attempts to connect to a MySQL server running on the host named `tonfisk' using an account with the user name `jon'. Due to this behavior, problems can occasionally arise when no value is provided for an option that expects one. Consider the following example, where a user connects to a MySQL server running on host `tonfisk' as user `jon': shell> mysql --host 85.224.35.45 --user jon Welcome to the MySQL monitor. Commands end with ; or \g. Your MySQL connection id is 3 Server version: 5.1.59 Source distribution Type 'help;' or '\h' for help. Type '\c' to clear the buffer. mysql> SELECT CURRENT_USER(); +----------------+ | CURRENT_USER() | +----------------+ | jon@% | +----------------+ 1 row in set (0.00 sec) Omitting the required value for one of these option yields an error, such as the one shown here: shell> mysql --host 85.224.35.45 --user `mysql: option '--user' requires an argument' In this case, *Note `mysql': mysql. was unable to find a value following the `--user' option because nothing came after it on the command line. However, if you omit the value for an option that is _not_ the last option to be used, you obtain a different error that you may not be expecting: shell> mysql --host --user jon `ERROR 2005 (HY000): Unknown MySQL server host '--user' (1)' Because *Note `mysql': mysql. assumes that any string following `--host' on the command line is a host name, `--host' `--user' is interpreted as `--host=--user', and the client attempts to connect to a MySQL server running on a host named `--user'. Options having default values always require an equal sign when assigning a value; failing to do so causes an error. For example, the MySQL server `--log-error' option has the default value `HOST_NAME.err', where HOST_NAME is the name of the host on which MySQL is running. Assume that you are running MySQL on a computer whose host name is `tonfisk', and consider the following invocation of *Note `mysqld_safe': mysqld-safe.: shell> mysqld_safe & [1] 11699 shell> 080112 12:53:40 mysqld_safe Logging to '/usr/local/mysql/var/tonfisk.err'. 080112 12:53:40 mysqld_safe Starting mysqld daemon with databases from /usr/local/mysql/var shell> After shutting down the server, restart it as follows: shell> mysqld_safe --log-error & [1] 11699 shell> 080112 12:53:40 mysqld_safe Logging to '/usr/local/mysql/var/tonfisk.err'. 080112 12:53:40 mysqld_safe Starting mysqld daemon with databases from /usr/local/mysql/var shell> The result is the same, since `--log-error' is not followed by anything else on the command line, and it supplies its own default value. (The `&' character tells the operating system to run MySQL in the background; it is ignored by MySQL itself.) Now suppose that you wish to log errors to a file named `my-errors.err'. You might try starting the server with `--log-error my-errors', but this does not have the intended effect, as shown here: shell> mysqld_safe --log-error my-errors & [1] 31357 shell> 080111 22:53:31 mysqld_safe Logging to '/usr/local/mysql/var/tonfisk.err'. 080111 22:53:32 mysqld_safe Starting mysqld daemon with databases from /usr/local/mysql/var 080111 22:53:34 mysqld_safe mysqld from pid file /usr/local/mysql/var/tonfisk.pid ended [1]+ Done ./mysqld_safe --log-error my-errors The server attempted to start using `/usr/local/mysql/var/tonfisk.err' as the error log, but then shut down. Examining the last few lines of this file shows the reason: shell> tail /usr/local/mysql/var/tonfisk.err 080111 22:53:32 InnoDB: Started; log sequence number 0 46409 `/usr/local/mysql/libexec/mysqld: Too many arguments (first extra is 'my-errors'). Use --verbose --help to get a list of available options' 080111 22:53:32 `[ERROR] Aborting' 080111 22:53:32 InnoDB: Starting shutdown... 080111 22:53:34 InnoDB: Shutdown completed; log sequence number 0 46409 080111 22:53:34 [Note] /usr/local/mysql/libexec/mysqld: Shutdown complete 080111 22:53:34 mysqld_safe mysqld from pid file /usr/local/mysql/var/tonfisk.pid ended Because the `--log-error' option supplies a default value, you must use an equal sign to assign a different value to it, as shown here: shell> mysqld_safe --log-error=my-errors & [1] 31437 shell> 080111 22:54:15 mysqld_safe Logging to '/usr/local/mysql/var/my-errors.err'. 080111 22:54:15 mysqld_safe Starting mysqld daemon with databases from /usr/local/mysql/var shell> Now the server has been started successfully, and is logging errors to the file `/usr/local/mysql/var/my-errors.err'. Similar issues can arise when specifying option values in option files. For example, consider a `my.cnf' file that contains the following: [mysql] host user When the *Note `mysql': mysql. client reads this file, these entries are parsed as `--host' `--user' or `--host=--user', with the result shown here: shell> mysql `ERROR 2005 (HY000): Unknown MySQL server host '--user' (1)' However, in option files, an equal sign is not assumed. Suppose the `my.cnf' file is as shown here: [mysql] user jon Trying to start *Note `mysql': mysql. in this case causes a different error: shell> mysql `mysql: unknown option '--user jon'' A similar error would occur if you were to write `host tonfisk' in the option file rather than `host=tonfisk'. Instead, you must use the equals sign: [mysql] user=jon Now the login attempt succeeds: shell> mysql Welcome to the MySQL monitor. Commands end with ; or \g. Your MySQL connection id is 5 Server version: 5.1.59 Source distribution Type 'help;' or '\h' for help. Type '\c' to clear the buffer. mysql> SELECT USER(); +---------------+ | USER() | +---------------+ | jon@localhost | +---------------+ 1 row in set (0.00 sec) This is not the same behavior as with the command line, where the equal sign is not required: shell> mysql --user jon --host tonfisk Welcome to the MySQL monitor. Commands end with ; or \g. Your MySQL connection id is 6 Server version: 5.1.59 Source distribution Type 'help;' or '\h' for help. Type '\c' to clear the buffer. mysql> SELECT USER(); +---------------+ | USER() | +---------------+ | jon@tonfisk | +---------------+ 1 row in set (0.00 sec)  File: manual.info, Node: setting-environment-variables, Prev: program-options, Up: programs-using 5.2.4 Setting Environment Variables ----------------------------------- Environment variables can be set at the command prompt to affect the current invocation of your command processor, or set permanently to affect future invocations. To set a variable permanently, you can set it in a startup file or by using the interface provided by your system for this purpose. Consult the documentation for your command interpreter for specific details. *Note environment-variables::, lists all environment variables that affect MySQL program operation. To specify a value for an environment variable, use the syntax appropriate for your command processor. For example, on Windows or NetWare, you can set the `USER' variable to specify your MySQL account name. To do so, use this syntax: SET USER=YOUR_NAME The syntax on Unix depends on your shell. Suppose that you want to specify the TCP/IP port number using the `MYSQL_TCP_PORT' variable. Typical syntax (such as for `sh', `bash', `zsh', and so on) is as follows: MYSQL_TCP_PORT=3306 export MYSQL_TCP_PORT The first command sets the variable, and the `export' command exports the variable to the shell environment so that its value becomes accessible to MySQL and other processes. For `csh' and `tcsh', use `setenv' to make the shell variable available to the environment: setenv MYSQL_TCP_PORT 3306 The commands to set environment variables can be executed at your command prompt to take effect immediately, but the settings persist only until you log out. To have the settings take effect each time you log in, use the interface provided by your system or place the appropriate command or commands in a startup file that your command interpreter reads each time it starts. On Windows, you can set environment variables using the System Control Panel (under Advanced). On Unix, typical shell startup files are `.bashrc' or `.bash_profile' for `bash', or `.tcshrc' for `tcsh'. Suppose that your MySQL programs are installed in `/usr/local/mysql/bin' and that you want to make it easy to invoke these programs. To do this, set the value of the `PATH' environment variable to include that directory. For example, if your shell is `bash', add the following line to your `.bashrc' file: PATH=${PATH}:/usr/local/mysql/bin `bash' uses different startup files for login and nonlogin shells, so you might want to add the setting to `.bashrc' for login shells and to `.bash_profile' for nonlogin shells to make sure that `PATH' is set regardless. If your shell is `tcsh', add the following line to your `.tcshrc' file: setenv PATH ${PATH}:/usr/local/mysql/bin If the appropriate startup file does not exist in your home directory, create it with a text editor. After modifying your `PATH' setting, open a new console window on Windows or log in again on Unix so that the setting goes into effect.  File: manual.info, Node: programs-server, Next: programs-installation, Prev: programs-using, Up: programs 5.3 MySQL Server and Server-Startup Programs ============================================ * Menu: * mysqld:: `mysqld' --- The MySQL Server * mysqld-safe:: `mysqld_safe' --- MySQL Server Startup Script * mysql-server:: `mysql.server' --- MySQL Server Startup Script * mysqld-multi:: `mysqld_multi' --- Manage Multiple MySQL Servers This section describes *Note `mysqld': mysqld, the MySQL server, and several programs that are used to start the server.  File: manual.info, Node: mysqld, Next: mysqld-safe, Prev: programs-server, Up: programs-server 5.3.1 `mysqld' -- The MySQL Server ---------------------------------- *Note `mysqld': mysqld, also known as MySQL Server, is the main program that does most of the work in a MySQL installation. MySQL Server manages access to the MySQL data directory that contains databases and tables. The data directory is also the default location for other information such as log files and status files. When MySQL server starts, it listens for network connections from client programs and manages access to databases on behalf of those clients. The *Note `mysqld': mysqld. program has many options that can be specified at startup. For a complete list of options, run this command: shell> mysqld --verbose --help MySQL Server also has a set of system variables that affect its operation as it runs. System variables can be set at server startup, and many of them can be changed at runtime to effect dynamic server reconfiguration. MySQL Server also has a set of status variables that provide information about its operation. You can monitor these status variables to access runtime performance characteristics. For a full description of MySQL Server command options, system variables, and status variables, see *Note mysqld-server::. For information about installing MySQL and setting up the initial configuration, see *Note installing::.  File: manual.info, Node: mysqld-safe, Next: mysql-server, Prev: mysqld, Up: programs-server 5.3.2 `mysqld_safe' -- MySQL Server Startup Script -------------------------------------------------- *Note `mysqld_safe': mysqld-safe. is the recommended way to start a *Note `mysqld': mysqld. server on Unix and NetWare. *Note `mysqld_safe': mysqld-safe. adds some safety features such as restarting the server when an error occurs and logging runtime information to an error log file. Descriptions of error logging and NetWare-specific behaviors are given later in this section. *Note*: In MySQL 5.1.20 (only), the default error logging behavior with *Note `mysqld_safe': mysqld-safe. is to write errors to `syslog' on systems that support the `logger' program. This differs from the default behavior of writing an error log file for other versions. *In 5.1.20, logging to `syslog' may fail to operate correctly in some cases; if so, use `--skip-syslog' to use the default log file or `--log-error=FILE_NAME' to specify a log file name explicitly.* *Note `mysqld_safe': mysqld-safe. tries to start an executable named *Note `mysqld': mysqld. To override the default behavior and specify explicitly the name of the server you want to run, specify a `--mysqld' or `--mysqld-version' option to *Note `mysqld_safe': mysqld-safe. You can also use `--ledir' to indicate the directory where *Note `mysqld_safe': mysqld-safe. should look for the server. Many of the options to *Note `mysqld_safe': mysqld-safe. are the same as the options to *Note `mysqld': mysqld. See *Note server-options::. Options unknown to *Note `mysqld_safe': mysqld-safe. are passed to *Note `mysqld': mysqld. if they are specified on the command line, but ignored if they are specified in the `[mysqld_safe]' group of an option file. See *Note option-files::. *Note `mysqld_safe': mysqld-safe. reads all options from the `[mysqld]', `[server]', and `[mysqld_safe]' sections in option files. For example, if you specify a `[mysqld]' section like this, *Note `mysqld_safe': mysqld-safe. will find and use the `--log-error' option: [mysqld] log-error=error.log For backward compatibility, *Note `mysqld_safe': mysqld-safe. also reads `[safe_mysqld]' sections, although you should rename such sections to `[mysqld_safe]' in MySQL 5.1 installations. *Note `mysqld_safe': mysqld-safe. supports the options in the following list. It also reads option files and supports the options for processing them described at *Note option-file-options::. *`mysqld_safe' Options* Format Option File Description IntroductionDeprecatedRemoved -autoclose autoclose On NetWare, mysqld_safe provides a screen presence -basedir=pathbasedir The path to the MySQL installation directory -core-file-size=sizecore-file-sizeThe size of the core file that mysqld should be able to create -datadir=pathdatadir The path to the data directory -defaults-extra-file=pathdefaults-extra-fileThe name of an option file to be read in addition to the usual option files -defaults-file=file_namedefaults-fileThe name of an option file to be read instead of the usual option files -help Display a help message and exit -ledir=path ledir Use this option to indicate the path name to the directory where the server is located -log-error=file_namelog-error Write the error log to the given file -mysqld=prog_namemysqld The name of the server program (in the ledir directory) that you want to start -mysqld-version=suffixmysqld-versionThis option is similar to the -mysqld option, but you specify only the suffix for the server program name -nice=prioritynice Use the nice program to set the server's scheduling priority to the given value -no-defaultsno-defaults Do not read any option files -open-files-limit=countopen-files-limitThe number of files that mysqld should be able to open -pid-file=file_namepid-file=file_nameThe path name of the process ID file -port=numberport The port number that the server should use when listening for TCP/IP connections -skip-kill-mysqldskip-kill-mysqldDo not try to kill stray mysqld processes -skip-syslogskip-syslog Do not write error messages 5.1.20 to syslog; use error log file -socket=pathsocket The Unix socket file that the server should use when listening for local connections -syslog syslog Write error messages to 5.1.20 syslog -timezone=timezonetimezone Set the TZ time zone environment variable to the given option value -user={user_name|user_id}user Run the mysqld server as the user having the name user_name or the numeric user ID user_id * `--help' Display a help message and exit. * `--autoclose' (NetWare only) On NetWare, *Note `mysqld_safe': mysqld-safe. provides a screen presence. When you unload (shut down) the *Note `mysqld_safe': mysqld-safe. NLM, the screen does not by default go away. Instead, it prompts for user input: ** If you want NetWare to close the screen automatically instead, use the `--autoclose' option to *Note `mysqld_safe': mysqld-safe. * `--basedir=PATH' The path to the MySQL installation directory. * `--core-file-size=SIZE' The size of the core file that *Note `mysqld': mysqld. should be able to create. The option value is passed to `ulimit -c'. * `--datadir=PATH' The path to the data directory. * `--defaults-extra-file=PATH' The name of an option file to be read in addition to the usual option files. This must be the first option on the command line if it is used. If the file does not exist or is otherwise inaccessible, the server will exit with an error. * `--defaults-file=FILE_NAME' The name of an option file to be read instead of the usual option files. This must be the first option on the command line if it is used. * `--ledir=PATH' If *Note `mysqld_safe': mysqld-safe. cannot find the server, use this option to indicate the path name to the directory where the server is located. * `--log-error=FILE_NAME' Write the error log to the given file. See *Note error-log::. * `--mysqld=PROG_NAME' The name of the server program (in the `ledir' directory) that you want to start. This option is needed if you use the MySQL binary distribution but have the data directory outside of the binary distribution. If *Note `mysqld_safe': mysqld-safe. cannot find the server, use the `--ledir' option to indicate the path name to the directory where the server is located. * `--mysqld-version=SUFFIX' This option is similar to the `--mysqld' option, but you specify only the suffix for the server program name. The basename is assumed to be *Note `mysqld': mysqld. For example, if you use `--mysqld-version=debug', *Note `mysqld_safe': mysqld-safe. starts the *Note `mysqld-debug': mysqld. program in the `ledir' directory. If the argument to `--mysqld-version' is empty, *Note `mysqld_safe': mysqld-safe. uses *Note `mysqld': mysqld. in the `ledir' directory. * `--nice=PRIORITY' Use the `nice' program to set the server's scheduling priority to the given value. * `--no-defaults' Do not read any option files. This must be the first option on the command line if it is used. * `--open-files-limit=COUNT' The number of files that *Note `mysqld': mysqld. should be able to open. The option value is passed to `ulimit -n'. Note that you need to start *Note `mysqld_safe': mysqld-safe. as `root' for this to work properly! * `--pid-file=FILE_NAME' The path name of the process ID file. * `--port=PORT_NUM' The port number that the server should use when listening for TCP/IP connections. The port number must be 1024 or higher unless the server is started by the `root' system user. * `--skip-kill-mysqld' Do not try to kill stray *Note `mysqld': mysqld. processes at startup. This option works only on Linux. * `--socket=PATH' The Unix socket file that the server should use when listening for local connections. * `--syslog', `--skip-syslog' `--syslog' causes error messages to be sent to `syslog' on systems that support the `logger' program. `--skip-syslog' suppresses the use of `syslog'; messages are written to an error log file. These options were added in MySQL 5.1.20. * `--syslog-tag=TAG' For logging to `syslog', messages from *Note `mysqld_safe': mysqld-safe. and *Note `mysqld': mysqld. are written with a tag of `mysqld_safe' and `mysqld', respectively. To specify a suffix for the tag, use `--syslog-tag=TAG', which modifies the tags to be `mysqld_safe-TAG' and `mysqld-TAG'. This option was added in MySQL 5.1.21. * `--timezone=TIMEZONE' Set the `TZ' time zone environment variable to the given option value. Consult your operating system documentation for legal time zone specification formats. * `--user={USER_NAME|USER_ID}' Run the *Note `mysqld': mysqld. server as the user having the name USER_NAME or the numeric user ID USER_ID. (`User' in this context refers to a system login account, not a MySQL user listed in the grant tables.) If you execute *Note `mysqld_safe': mysqld-safe. with the `--defaults-file' or `--defaults-extra-file' option to name an option file, the option must be the first one given on the command line or the option file will not be used. For example, this command will not use the named option file: mysql> mysqld_safe --port=PORT_NUM --defaults-file=FILE_NAME Instead, use the following command: mysql> mysqld_safe --defaults-file=FILE_NAME --port=PORT_NUM The *Note `mysqld_safe': mysqld-safe. script is written so that it normally can start a server that was installed from either a source or a binary distribution of MySQL, even though these types of distributions typically install the server in slightly different locations. (See *Note installation-layouts::.) *Note `mysqld_safe': mysqld-safe. expects one of the following conditions to be true: * The server and databases can be found relative to the working directory (the directory from which *Note `mysqld_safe': mysqld-safe. is invoked). For binary distributions, *Note `mysqld_safe': mysqld-safe. looks under its working directory for `bin' and `data' directories. For source distributions, it looks for `libexec' and `var' directories. This condition should be met if you execute *Note `mysqld_safe': mysqld-safe. from your MySQL installation directory (for example, `/usr/local/mysql' for a binary distribution). * If the server and databases cannot be found relative to the working directory, *Note `mysqld_safe': mysqld-safe. attempts to locate them by absolute path names. Typical locations are `/usr/local/libexec' and `/usr/local/var'. The actual locations are determined from the values configured into the distribution at the time it was built. They should be correct if MySQL is installed in the location specified at configuration time. Because *Note `mysqld_safe': mysqld-safe. tries to find the server and databases relative to its own working directory, you can install a binary distribution of MySQL anywhere, as long as you run *Note `mysqld_safe': mysqld-safe. from the MySQL installation directory: shell> cd MYSQL_INSTALLATION_DIRECTORY shell> bin/mysqld_safe & If *Note `mysqld_safe': mysqld-safe. fails, even when invoked from the MySQL installation directory, you can specify the `--ledir' and `--datadir' options to indicate the directories in which the server and databases are located on your system. When you use *Note `mysqld_safe': mysqld-safe. to start *Note `mysqld': mysqld, *Note `mysqld_safe': mysqld-safe. arranges for error (and notice) messages from itself and from *Note `mysqld': mysqld. to go to the same destination. As of MySQL 5.1.20, there are several *Note `mysqld_safe': mysqld-safe. options for controlling the destination of these messages: * `--syslog': Write error messages to `syslog' on systems that support the `logger' program. * `--skip-syslog': Do not write error messages to `syslog'. Messages are written to the default error log file (`HOST_NAME.err' in the data directory), or to a named file if the `--log-error' option is given. * `--log-error=FILE_NAME': Write error messages to the named error file. If none of these options is given, the default is `--skip-syslog'. *Note*: In MySQL 5.1.20 _only_, the default is `--syslog'. This differs from logging behavior for other versions of MySQL, for which the default is to write messages to the default error log file. If `--syslog' and `--log-error' are both given, a warning is issued and `--log-error' takes precedence. When *Note `mysqld_safe': mysqld-safe. writes a message, notices go to the logging destination (`syslog' or the error log file) and `stdout'. Errors go to the logging destination and `stderr'. Before MySQL 5.1.20, error logging is controlled only with the `--log-error' option. If it is given, messages go to the named error file. Otherwise, messages go to the default error file. Normally, you should not edit the *Note `mysqld_safe': mysqld-safe. script. Instead, configure *Note `mysqld_safe': mysqld-safe. by using command-line options or options in the `[mysqld_safe]' section of a `my.cnf' option file. In rare cases, it might be necessary to edit *Note `mysqld_safe': mysqld-safe. to get it to start the server properly. However, if you do this, your modified version of *Note `mysqld_safe': mysqld-safe. might be overwritten if you upgrade MySQL in the future, so you should make a copy of your edited version that you can reinstall. On NetWare, *Note `mysqld_safe': mysqld-safe. is a NetWare Loadable Module (NLM) that is ported from the original Unix shell script. It starts the server as follows: 1. Runs a number of system and option checks. 2. Runs a check on `MyISAM' tables. 3. Provides a screen presence for the MySQL server. 4. Starts *Note `mysqld': mysqld, monitors it, and restarts it if it terminates in error. 5. Sends error messages from *Note `mysqld': mysqld. to the `HOST_NAME.err' file in the data directory. 6. Sends *Note `mysqld_safe': mysqld-safe. screen output to the `HOST_NAME.safe' file in the data directory.  File: manual.info, Node: mysql-server, Next: mysqld-multi, Prev: mysqld-safe, Up: programs-server 5.3.3 `mysql.server' -- MySQL Server Startup Script --------------------------------------------------- MySQL distributions on Unix include a script named *Note `mysql.server': mysql-server. It can be used on systems such as Linux and Solaris that use System V-style run directories to start and stop system services. It is also used by the Mac OS X Startup Item for MySQL. *Note `mysql.server': mysql-server. can be found in the `support-files' directory under your MySQL installation directory or in a MySQL source distribution. If you use the Linux server RPM package (`MySQL-server-VERSION.rpm'), the *Note `mysql.server': mysql-server. script will be installed in the `/etc/init.d' directory with the name `mysql'. You need not install it manually. See *Note linux-installation-rpm::, for more information on the Linux RPM packages. Some vendors provide RPM packages that install a startup script under a different name such as *Note `mysqld': mysqld. If you install MySQL from a source distribution or using a binary distribution format that does not install *Note `mysql.server': mysql-server. automatically, you can install it manually. Instructions are provided in *Note automatic-start::. *Note `mysql.server': mysql-server. reads options from the `[mysql.server]' and `[mysqld]' sections of option files. For backward compatibility, it also reads `[mysql_server]' sections, although you should rename such sections to `[mysql.server]' when using MySQL 5.1. *Note `mysql.server': mysql-server. supports the following options. * `--basedir=PATH' The path to the MySQL installation directory. * `--datadir=PATH' The path to the MySQL data directory. * `--pid-file=FILE_NAME' The path name of the file in which the server should write its process ID. * `--service-startup-timeout=FILE_NAME' How long in seconds to wait for confirmation of server startup. If the server does not start within this time, *Note `mysql.server': mysql-server. exits with an error. The default value is 900. A value of 0 means not to wait at all for startup. Negative values mean to wait forever (no timeout). This option was added in MySQL 5.1.17. Before that, a value of 900 is always used. * `--use-mysqld_safe' Use *Note `mysqld_safe': mysqld-safe. to start the server. This is the default. * `--use-manager' Use Instance Manager to start the server. * `--user=USER_NAME' The login user name to use for running *Note `mysqld': mysqld.  File: manual.info, Node: mysqld-multi, Prev: mysql-server, Up: programs-server 5.3.4 `mysqld_multi' -- Manage Multiple MySQL Servers ----------------------------------------------------- *Note `mysqld_multi': mysqld-multi. is designed to manage several *Note `mysqld': mysqld. processes that listen for connections on different Unix socket files and TCP/IP ports. It can start or stop servers, or report their current status. The MySQL Instance Manager is an alternative means of managing multiple servers (see *Note instance-manager::). *Note `mysqld_multi': mysqld-multi. searches for groups named `[mysqldN]' in `my.cnf' (or in the file named by the `--config-file' option). N can be any positive integer. This number is referred to in the following discussion as the option group number, or GNR. Group numbers distinguish option groups from one another and are used as arguments to *Note `mysqld_multi': mysqld-multi. to specify which servers you want to start, stop, or obtain a status report for. Options listed in these groups are the same that you would use in the `[mysqld]' group used for starting *Note `mysqld': mysqld. (See, for example, *Note automatic-start::.) However, when using multiple servers, it is necessary that each one use its own value for options such as the Unix socket file and TCP/IP port number. For more information on which options must be unique per server in a multiple-server environment, see *Note multiple-servers::. To invoke *Note `mysqld_multi': mysqld-multi, use the following syntax: shell> mysqld_multi [OPTIONS] {start|stop|report} [GNR[,GNR] ...] `start', `stop', and `report' indicate which operation to perform. You can perform the designated operation for a single server or multiple servers, depending on the GNR list that follows the option name. If there is no list, *Note `mysqld_multi': mysqld-multi. performs the operation for all servers in the option file. Each GNR value represents an option group number or range of group numbers. The value should be the number at the end of the group name in the option file. For example, the GNR for a group named `[mysqld17]' is `17'. To specify a range of numbers, separate the first and last numbers by a dash. The GNR value `10-13' represents groups `[mysqld10]' through `[mysqld13]'. Multiple groups or group ranges can be specified on the command line, separated by commas. There must be no whitespace characters (spaces or tabs) in the GNR list; anything after a whitespace character is ignored. This command starts a single server using option group `[mysqld17]': shell> mysqld_multi start 17 This command stops several servers, using option groups `[mysqld8]' and `[mysqld10]' through `[mysqld13]': shell> mysqld_multi stop 8,10-13 For an example of how you might set up an option file, use this command: shell> mysqld_multi --example As of MySQL 5.1.18, *Note `mysqld_multi': mysqld-multi. searches for option files as follows: * With `--no-defaults', no option files are read. * With `--defaults-file=FILE_NAME', only the named file is read. * Otherwise, option files in the standard list of locations are read, including any file named by the `--defaults-extra-file=FILE_NAME' option, if one is given. (If the option is given multiple times, the last value is used.) Before MySQL 5.1.18, the preceding options are not recognized. Files in the standard locations are read, and any file named by the `--config-file=FILE_NAME' option, if one is given. A file named by `--config-file' is read only for `[mysqldN]' option groups, not the `[mysqld_multi]' group. Option files read are searched for `[mysqld_multi]' and `[mysqldN]' option groups. The `[mysqld_multi]' group can be used for options to *Note `mysqld_multi': mysqld-multi. itself. `[mysqldN]' groups can be used for options passed to specific *Note `mysqld': mysqld. instances. As of MySQL 5.1.35, the `[mysqld]' or `[mysqld_safe]' groups can be used for common options read by all instances of *Note `mysqld': mysqld. or *Note `mysqld_safe': mysqld-safe. You can specify a `--defaults-file=FILE_NAME' option to use a different configuration file for that instance, in which case the `[mysqld]' or `[mysqld_safe]' groups from that file will be used for that instance. Before MySQL 5.1.35, some versions of *Note `mysqld_multi': mysqld-multi. pass the `--no-defaults' options to instances, so these techniques are inapplicable. *Note `mysqld_multi': mysqld-multi. supports the following options. * `--help' Display a help message and exit. * `--config-file=FILE_NAME' As of MySQL 5.1.18, this option is deprecated. If given, it is treated the same way as `--defaults-extra-file', described earlier. `--config-file' is removed in MySQL 5.5. Before MySQL 5.1.18, this option specifies the name of an extra option file. It affects where *Note `mysqld_multi': mysqld-multi. looks for `[mysqldN]' option groups. Without this option, all options are read from the usual `my.cnf' file. The option does not affect where *Note `mysqld_multi': mysqld-multi. reads its own options, which are always taken from the `[mysqld_multi]' group in the usual `my.cnf' file. * `--example' Display a sample option file. * `--log=FILE_NAME' Specify the name of the log file. If the file exists, log output is appended to it. * `--mysqladmin=PROG_NAME' The *Note `mysqladmin': mysqladmin. binary to be used to stop servers. * `--mysqld=PROG_NAME' The *Note `mysqld': mysqld. binary to be used. Note that you can specify *Note `mysqld_safe': mysqld-safe. as the value for this option also. If you use *Note `mysqld_safe': mysqld-safe. to start the server, you can include the `mysqld' or `ledir' options in the corresponding `[mysqldN]' option group. These options indicate the name of the server that *Note `mysqld_safe': mysqld-safe. should start and the path name of the directory where the server is located. (See the descriptions for these options in *Note mysqld-safe::.) Example: [mysqld38] mysqld = mysqld-debug ledir = /opt/local/mysql/libexec * `--no-log' Print log information to `stdout' rather than to the log file. By default, output goes to the log file. * `--password=PASSWORD' The password of the MySQL account to use when invoking *Note `mysqladmin': mysqladmin. Note that the password value is not optional for this option, unlike for other MySQL programs. * `--silent' Silent mode; disable warnings. * `--tcp-ip' Connect to each MySQL server through the TCP/IP port instead of the Unix socket file. (If a socket file is missing, the server might still be running, but accessible only through the TCP/IP port.) By default, connections are made using the Unix socket file. This option affects `stop' and `report' operations. * `--user=USER_NAME' The user name of the MySQL account to use when invoking *Note `mysqladmin': mysqladmin. * `--verbose' Be more verbose. * `--version' Display version information and exit. Some notes about *Note `mysqld_multi': mysqld-multi.: * *Most important*: Before using *Note `mysqld_multi': mysqld-multi. be sure that you understand the meanings of the options that are passed to the *Note `mysqld': mysqld. servers and _why_ you would want to have separate *Note `mysqld': mysqld. processes. Beware of the dangers of using multiple *Note `mysqld': mysqld. servers with the same data directory. Use separate data directories, unless you _know_ what you are doing. Starting multiple servers with the same data directory does _not_ give you extra performance in a threaded system. See *Note multiple-servers::. * *Important*: Make sure that the data directory for each server is fully accessible to the Unix account that the specific *Note `mysqld': mysqld. process is started as. _Do not_ use the Unix ROOT account for this, unless you _know_ what you are doing. See *Note changing-mysql-user::. * Make sure that the MySQL account used for stopping the *Note `mysqld': mysqld. servers (with the *Note `mysqladmin': mysqladmin. program) has the same user name and password for each server. Also, make sure that the account has the `SHUTDOWN' privilege. If the servers that you want to manage have different user names or passwords for the administrative accounts, you might want to create an account on each server that has the same user name and password. For example, you might set up a common `multi_admin' account by executing the following commands for each server: shell> mysql -u root -S /tmp/mysql.sock -p Enter password: mysql> GRANT SHUTDOWN ON *.* -> TO 'multi_admin'@'localhost' IDENTIFIED BY 'multipass'; See *Note privilege-system::. You have to do this for each *Note `mysqld': mysqld. server. Change the connection parameters appropriately when connecting to each one. Note that the host name part of the account name must permit you to connect as `multi_admin' from the host where you want to run *Note `mysqld_multi': mysqld-multi. * The Unix socket file and the TCP/IP port number must be different for every *Note `mysqld': mysqld. (Alternatively, if the host has multiple network addresses, you can use `--bind-address' to cause different servers to listen to different interfaces.) * The `--pid-file' option is very important if you are using *Note `mysqld_safe': mysqld-safe. to start *Note `mysqld': mysqld. (for example, `--mysqld=mysqld_safe') Every *Note `mysqld': mysqld. should have its own process ID file. The advantage of using *Note `mysqld_safe': mysqld-safe. instead of *Note `mysqld': mysqld. is that *Note `mysqld_safe': mysqld-safe. monitors its *Note `mysqld': mysqld. process and restarts it if the process terminates due to a signal sent using `kill -9' or for other reasons, such as a segmentation fault. Please note that the *Note `mysqld_safe': mysqld-safe. script might require that you start it from a certain place. This means that you might have to change location to a certain directory before running *Note `mysqld_multi': mysqld-multi. If you have problems starting, please see the *Note `mysqld_safe': mysqld-safe. script. Check especially the lines: ---------------------------------------------------------------- MY_PWD=`pwd` # Check if we are starting this relative (for the binary release) if test -d $MY_PWD/data/mysql -a \ -f ./share/mysql/english/errmsg.sys -a \ -x ./bin/mysqld ---------------------------------------------------------------- The test performed by these lines should be successful, or you might encounter problems. See *Note mysqld-safe::. * You might want to use the `--user' option for *Note `mysqld': mysqld, but to do this you need to run the *Note `mysqld_multi': mysqld-multi. script as the Unix superuser (`root'). Having the option in the option file doesn't matter; you just get a warning if you are not the superuser and the *Note `mysqld': mysqld. processes are started under your own Unix account. The following example shows how you might set up an option file for use with *Note `mysqld_multi': mysqld-multi. The order in which the *Note `mysqld': mysqld. programs are started or stopped depends on the order in which they appear in the option file. Group numbers need not form an unbroken sequence. The first and fifth `[mysqldN]' groups were intentionally omitted from the example to illustrate that you can have `gaps' in the option file. This gives you more flexibility. # This file should probably be in your home dir (~/.my.cnf) # or /etc/my.cnf # Version 2.1 by Jani Tolonen [mysqld_multi] mysqld = /usr/local/bin/mysqld_safe mysqladmin = /usr/local/bin/mysqladmin user = multi_admin password = multipass [mysqld2] socket = /tmp/mysql.sock2 port = 3307 pid-file = /usr/local/mysql/var2/hostname.pid2 datadir = /usr/local/mysql/var2 language = /usr/local/share/mysql/english user = john [mysqld3] socket = /tmp/mysql.sock3 port = 3308 pid-file = /usr/local/mysql/var3/hostname.pid3 datadir = /usr/local/mysql/var3 language = /usr/local/share/mysql/swedish user = monty [mysqld4] socket = /tmp/mysql.sock4 port = 3309 pid-file = /usr/local/mysql/var4/hostname.pid4 datadir = /usr/local/mysql/var4 language = /usr/local/share/mysql/estonia user = tonu [mysqld6] socket = /tmp/mysql.sock6 port = 3311 pid-file = /usr/local/mysql/var6/hostname.pid6 datadir = /usr/local/mysql/var6 language = /usr/local/share/mysql/japanese user = jani See *Note option-files::.  File: manual.info, Node: programs-installation, Next: programs-client, Prev: programs-server, Up: programs 5.4 MySQL Installation-Related Programs ======================================= * Menu: * comp-err:: `comp_err' --- Compile MySQL Error Message File * make-win-bin-dist:: `make_win_bin_dist' --- Package MySQL Distribution as Zip Archive * mysqlbug:: `mysqlbug' --- Generate Bug Report * mysql-fix-privilege-tables:: `mysql_fix_privilege_tables' --- Upgrade MySQL System Tables * mysql-install-db:: `mysql_install_db' --- Initialize MySQL Data Directory * mysql-secure-installation:: `mysql_secure_installation' --- Improve MySQL Installation Security * mysql-tzinfo-to-sql:: `mysql_tzinfo_to_sql' --- Load the Time Zone Tables * mysql-upgrade:: `mysql_upgrade' --- Check Tables for MySQL Upgrade The programs in this section are used when installing or upgrading MySQL.  File: manual.info, Node: comp-err, Next: make-win-bin-dist, Prev: programs-installation, Up: programs-installation 5.4.1 `comp_err' -- Compile MySQL Error Message File ---------------------------------------------------- *Note `comp_err': comp-err. creates the `errmsg.sys' file that is used by *Note `mysqld': mysqld. to determine the error messages to display for different error codes. *Note `comp_err': comp-err. normally is run automatically when MySQL is built. It compiles the `errmsg.sys' file from the plaintext file located at `sql/share/errmsg.txt' in MySQL source distributions. *Note `comp_err': comp-err. also generates `mysqld_error.h', `mysqld_ername.h', and `sql_state.h' header files. For more information about how error messages are defined, see the MySQL Internals Manual, available at `http://forge.mysql.com/wiki/MySQL_Internals'. Invoke *Note `comp_err': comp-err. like this: shell> comp_err [OPTIONS] *Note `comp_err': comp-err. supports the following options. * `--help', `-?' Display a help message and exit. * `--charset=PATH', `-C PATH' The character set directory. The default is `../sql/share/charsets'. * `--debug=DEBUG_OPTIONS', `-# DEBUG_OPTIONS' Write a debugging log. A typical DEBUG_OPTIONS string is `'d:t:O,FILE_NAME''. The default is `'d:t:O,/tmp/comp_err.trace''. * `--debug-info', `-T' Print some debugging information when the program exits. * `--header_file=FILE_NAME', `-H FILE_NAME' The name of the error header file. The default is `mysqld_error.h'. * `--in_file=FILE_NAME', `-F FILE_NAME' The name of the input file. The default is `../sql/share/errmsg.txt'. * `--name_file=FILE_NAME', `-N FILE_NAME' The name of the error name file. The default is `mysqld_ername.h'. * `--out_dir=PATH', `-D PATH' The name of the output base directory. The default is `../sql/share/'. * `--out_file=FILE_NAME', `-O FILE_NAME' The name of the output file. The default is `errmsg.sys'. * `--statefile=FILE_NAME', `-S FILE_NAME' The name for the SQLSTATE header file. The default is `sql_state.h'. * `--version', `-V' Display version information and exit.  File: manual.info, Node: make-win-bin-dist, Next: mysqlbug, Prev: comp-err, Up: programs-installation 5.4.2 `make_win_bin_dist' -- Package MySQL Distribution as Zip Archive ---------------------------------------------------------------------- This script is used on Windows after building a MySQL distribution from source to create executable programs. It packages the binaries and support files into a Zip archive that can be unpacked at the location where you want to install MySQL. *Note `make_win_bin_dist': make-win-bin-dist. is a shell script, so you must have Cygwin installed to use it. This program's use is subject to change. Currently, you invoke it as follows from the root directory of your source distribution: shell> make_win_bin_dist [OPTIONS] PACKAGE_BASENAME [COPY_DEF ...] The PACKAGE_BASENAME argument provides the basename for the resulting Zip archive. This name will be the name of the directory that results from unpacking the archive. Because you might want to include files of directories from other builds, you can instruct this script to copy them in for you, using COPY_DEF arguments, which have the form RELATIVE_DEST_NAME=SOURCE_NAME. Example: bin/mysqld-max.exe=../my-max-build/sql/release/mysqld.exe If you specify a directory, the entire directory will be copied. *Note `make_win_bin_dist': make-win-bin-dist. supports the following options. * `--debug' Pack the debug binaries and produce an error if they were not built. * `--embedded' Pack the embedded server and produce an error if it was not built. The default is to pack it if it was built. * `--exe-suffix=SUFFIX' Add a suffix to the basename of the *Note `mysql': mysql. binary. For example, a suffix of `-abc' produces a binary named `mysqld-abc.exe'. * `--no-debug' Do not pack the debug binaries even if they were built. * `--no-embedded' Do not pack the embedded server even if it was built. * `--only-debug' Use this option when the target for this build was `Debug', and you just want to replace the normal binaries with debug versions (that is, do not use separate `debug' directories).  File: manual.info, Node: mysqlbug, Next: mysql-fix-privilege-tables, Prev: make-win-bin-dist, Up: programs-installation 5.4.3 `mysqlbug' -- Generate Bug Report --------------------------------------- This program enables you to generate a bug report and send it to Oracle Corporation. It is a shell script and runs on Unix. The normal way to report bugs is to visit `http://bugs.mysql.com/', which is the address for our bugs database. This database is public and can be browsed and searched by anyone. If you log in to the system, you can enter new reports. If you have no Web access, you can generate a bug report by using the *Note `mysqlbug': mysqlbug. script. *Note `mysqlbug': mysqlbug. helps you generate a report by determining much of the following information automatically, but if something important is missing, please include it with your message. *Note `mysqlbug': mysqlbug. can be found in the `scripts' directory (source distribution) and in the `bin' directory under your MySQL installation directory (binary distribution). Invoke *Note `mysqlbug': mysqlbug. without arguments: shell> mysqlbug The script will place you in an editor with a copy of the report to be sent. Edit the lines near the beginning that indicate the nature of the problem. Then write the file to save your changes, quit the editor, and *Note `mysqlbug': mysqlbug. will send the report by email.  File: manual.info, Node: mysql-fix-privilege-tables, Next: mysql-install-db, Prev: mysqlbug, Up: programs-installation 5.4.4 `mysql_fix_privilege_tables' -- Upgrade MySQL System Tables ----------------------------------------------------------------- *Note*: In MySQL 5.1.7, *Note `mysql_fix_privilege_tables': mysql-fix-privilege-tables. was superseded by *Note `mysql_upgrade': mysql-upgrade, which should be used instead. See *Note mysql-upgrade::. Some releases of MySQL introduce changes to the structure of the system tables in the `mysql' database to add new privileges or support new features. When you update to a new version of MySQL, you should update your system tables as well to make sure that their structure is up to date. Otherwise, there might be capabilities that you cannot take advantage of. *Note `mysql_fix_privilege_tables': mysql-fix-privilege-tables. is an older script that previously was used to uprade the system tables in the `mysql' database after a MySQL upgrade. Before running *Note `mysql_fix_privilege_tables': mysql-fix-privilege-tables, make a backup of your `mysql' database. On Unix or Unix-like systems, update the system tables by running the *Note `mysql_fix_privilege_tables': mysql-fix-privilege-tables. script: shell> mysql_fix_privilege_tables You must run this script while the server is running. It attempts to connect to the server running on the local host as `root'. If your `root' account requires a password, indicate the password on the command line like this: shell> mysql_fix_privilege_tables --password=ROOT_PASSWORD The *Note `mysql_fix_privilege_tables': mysql-fix-privilege-tables. script performs any actions necessary to convert your system tables to the current format. You might see some `Duplicate column name' warnings as it runs; you can ignore them. After running the script, stop the server and restart it so that any changes made to the system tables take effect. On Windows systems, MySQL distributions include a `mysql_fix_privilege_tables.sql' SQL script that you can run using the *Note `mysql': mysql. client. For example, if your MySQL installation is located at `C:\Program Files\MySQL\MySQL Server 5.1', the commands look like this: C:\> cd "C:\Program Files\MySQL\MySQL Server 5.1" C:\> bin\mysql -u root -p mysql mysql> SOURCE share/mysql_fix_privilege_tables.sql *Note*: Prior to version 5.1.17, the `mysql_fix_privilege_tables.sql' script is found in the `scripts' directory. The *Note `mysql': mysql. command will prompt you for the `root' password; enter it when prompted. If your installation is located in some other directory, adjust the path names appropriately. As with the Unix procedure, you might see some `Duplicate column name' warnings as *Note `mysql': mysql. processes the statements in the `mysql_fix_privilege_tables.sql' script; you can ignore them. After running the script, stop the server and restart it.  File: manual.info, Node: mysql-install-db, Next: mysql-secure-installation, Prev: mysql-fix-privilege-tables, Up: programs-installation 5.4.5 `mysql_install_db' -- Initialize MySQL Data Directory ----------------------------------------------------------- *Note `mysql_install_db': mysql-install-db. initializes the MySQL data directory and creates the system tables that it contains, if they do not exist. To invoke *Note `mysql_install_db': mysql-install-db, use the following syntax: shell> mysql_install_db [OPTIONS] Because the MySQL server, *Note `mysqld': mysqld, needs to access the data directory when it runs later, you should either run *Note `mysql_install_db': mysql-install-db. from the same account that will be used for running *Note `mysqld': mysqld. or run it as `root' and use the `--user' option to indicate the user name that *Note `mysqld': mysqld. will run as. It might be necessary to specify other options such as `--basedir' or `--datadir' if *Note `mysql_install_db': mysql-install-db. does not use the correct locations for the installation directory or data directory. For example: shell> bin/mysql_install_db --user=mysql \ --basedir=/opt/mysql/mysql \ --datadir=/opt/mysql/mysql/data *Note `mysql_install_db': mysql-install-db. needs to invoke *Note `mysqld': mysqld. with the `--bootstrap' and `--skip-grant-tables' options. If MySQL was configured with the `--disable-grant-options' option, `--bootstrap' and `--skip-grant-tables' will be disabled (see *Note source-configuration-options::). To handle this, set the `MYSQLD_BOOTSTRAP' environment variable to the full path name of a server that has all options enabled. *Note `mysql_install_db': mysql-install-db. will use that server. *Note*: If you have set a custom `TMPDIR' variable when performing the installation, and the specified directory is not accessible, the execution of *Note `mysql_install_db': mysql-install-db. may fail. You should unset `TMPDIR', or set `TMPDIR' to point to the system temporary directory (usually `/tmp'). *Note `mysql_install_db': mysql-install-db. supports the following options, which can be specified on the command line or in the `[mysql_install_db]' and (if they are common to *Note `mysqld': mysqld.) `[mysqld]' option file groups. * `--basedir=PATH' The path to the MySQL installation directory. * `--force' Cause *Note `mysql_install_db': mysql-install-db. to run even if DNS does not work. In that case, grant table entries that normally use host names will use IP addresses. * `--datadir=PATH', `--ldata=PATH' The path to the MySQL data directory. * `--rpm' For internal use. This option is used by RPM files during the MySQL installation process. * `--skip-name-resolve' Use IP addresses rather than host names when creating grant table entries. This option can be useful if your DNS does not work. * `--srcdir=PATH' For internal use. The directory under which *Note `mysql_install_db': mysql-install-db. looks for support files such as the error message file and the file for populating the help tables. This option was added in MySQL 5.1.14. * `--user=USER_NAME' The login user name to use for running *Note `mysqld': mysqld. Files and directories created by *Note `mysqld': mysqld. will be owned by this user. You must be `root' to use this option. By default, *Note `mysqld': mysqld. runs using your current login name and files and directories that it creates will be owned by you. * `--verbose' Verbose mode. Print more information about what the program does. * `--windows' For internal use. This option is used for creating Windows distributions.  File: manual.info, Node: mysql-secure-installation, Next: mysql-tzinfo-to-sql, Prev: mysql-install-db, Up: programs-installation 5.4.6 `mysql_secure_installation' -- Improve MySQL Installation Security ------------------------------------------------------------------------ This program enables you to improve the security of your MySQL installation in the following ways: * You can set a password for `root' accounts. * You can remove `root' accounts that are accessible from outside the local host. * You can remove anonymous-user accounts. * You can remove the `test' database (which by default can be accessed by all users, even anonymous users), and privileges that permit anyone to access databases with names that start with `test_'. *Note `mysql_secure_installation': mysql-secure-installation. helps you implement security recommendations similar to those described at *Note default-privileges::. Invoke *Note `mysql_secure_installation': mysql-secure-installation. without arguments: shell> mysql_secure_installation The script will prompt you to determine which actions to perform. *Note `mysql_secure_installation': mysql-secure-installation. is not available on Windows.  File: manual.info, Node: mysql-tzinfo-to-sql, Next: mysql-upgrade, Prev: mysql-secure-installation, Up: programs-installation 5.4.7 `mysql_tzinfo_to_sql' -- Load the Time Zone Tables -------------------------------------------------------- The *Note `mysql_tzinfo_to_sql': mysql-tzinfo-to-sql. program loads the time zone tables in the `mysql' database. It is used on systems that have a _zoneinfo_ database (the set of files describing time zones). Examples of such systems are Linux, FreeBSD, Solaris, and Mac OS X. One likely location for these files is the `/usr/share/zoneinfo' directory (`/usr/share/lib/zoneinfo' on Solaris). If your system does not have a zoneinfo database, you can use the downloadable package described in *Note time-zone-support::. *Note `mysql_tzinfo_to_sql': mysql-tzinfo-to-sql. can be invoked several ways: shell> mysql_tzinfo_to_sql TZ_DIR shell> mysql_tzinfo_to_sql TZ_FILE TZ_NAME shell> mysql_tzinfo_to_sql --leap TZ_FILE For the first invocation syntax, pass the zoneinfo directory path name to *Note `mysql_tzinfo_to_sql': mysql-tzinfo-to-sql. and send the output into the *Note `mysql': mysql. program. For example: shell> mysql_tzinfo_to_sql /usr/share/zoneinfo | mysql -u root mysql *Note `mysql_tzinfo_to_sql': mysql-tzinfo-to-sql. reads your system's time zone files and generates SQL statements from them. *Note `mysql': mysql. processes those statements to load the time zone tables. The second syntax causes *Note `mysql_tzinfo_to_sql': mysql-tzinfo-to-sql. to load a single time zone file TZ_FILE that corresponds to a time zone name TZ_NAME: shell> mysql_tzinfo_to_sql TZ_FILE TZ_NAME | mysql -u root mysql If your time zone needs to account for leap seconds, invoke *Note `mysql_tzinfo_to_sql': mysql-tzinfo-to-sql. using the third syntax, which initializes the leap second information. TZ_FILE is the name of your time zone file: shell> mysql_tzinfo_to_sql --leap TZ_FILE | mysql -u root mysql After running *Note `mysql_tzinfo_to_sql': mysql-tzinfo-to-sql, it is best to restart the server so that it does not continue to use any previously cached time zone data.  File: manual.info, Node: mysql-upgrade, Prev: mysql-tzinfo-to-sql, Up: programs-installation 5.4.8 `mysql_upgrade' -- Check Tables for MySQL Upgrade ------------------------------------------------------- *Note `mysql_upgrade': mysql-upgrade. examines all tables in all databases for incompatibilities with the current version of MySQL Server. *Note `mysql_upgrade': mysql-upgrade. also upgrades the system tables so that you can take advantage of new privileges or capabilities that might have been added. *Note `mysql_upgrade': mysql-upgrade. should be executed each time you upgrade MySQL. It supersedes the older *Note `mysql_fix_privilege_tables': mysql-fix-privilege-tables. script, which should no longer be used. If *Note `mysql_upgrade': mysql-upgrade. finds that a table has a possible incompatibility, it performs a table check and, if problems are found, attempts a table repair. If the table cannot be repaired, see *Note rebuilding-tables:: for manual table repair strategies. *Note*: On Windows Server 2008, Vista, and newer, you must run *Note `mysql_upgrade': mysql-upgrade. with administrator privileges. You can do this by running a Command Prompt as Administrator and running the command. Failure to do so may result in the upgrade failing to execute correctly. *Caution*: You should always back up your current MySQL installation _before_ performing an upgrade. See *Note backup-methods::. Some upgrade incompatibilities may require special handling before you upgrade your MySQL installation and run *Note `mysql_upgrade': mysql-upgrade. See *Note upgrading::, for instructions on determining whether any such incompatibilities apply to your installation and how to handle them. To use *Note `mysql_upgrade': mysql-upgrade, make sure that the server is running, and then invoke it like this: shell> mysql_upgrade [OPTIONS] After running *Note `mysql_upgrade': mysql-upgrade, stop the server and restart it so that any changes made to the system tables take effect. *Note `mysql_upgrade': mysql-upgrade. executes the following commands to check and repair tables and to upgrade the system tables: mysqlcheck --all-databases --check-upgrade --auto-repair mysql < FIX_PRIV_TABLES mysqlcheck --all-databases --check-upgrade --fix-db-names --fix-table-names Notes about the preceding commands: * Because *Note `mysql_upgrade': mysql-upgrade. invokes *Note `mysqlcheck': mysqlcheck. with the `--all-databases' option, it processes all tables in all databases, which might take a long time to complete. Each table is locked and therefore unavailable to other sessions while it is being processed. Check and repair operations can be time-consuming, particularly for large tables. * For details about what checks the `--check-upgrade' option entails, see the description of the `FOR UPGRADE' option of the *Note `CHECK TABLE': check-table. statement (see *Note check-table::). * FIX_PRIV_TABLES represents a script generated internally by *Note `mysql_upgrade': mysql-upgrade. that contains SQL statements to upgrade the tables in the `mysql' database. * Prior to MySQL 5.1.31, *Note `mysql_upgrade': mysql-upgrade. does not run the second *Note `mysqlcheck': mysqlcheck. command, which is necessary to re-encode database or table names that contain nonalphanumeric characters. (They still appear after the upgrade with the `#mysql50#' prefix described in *Note identifier-mapping::.) If you have such database or table names, execute the second *Note `mysqlcheck': mysqlcheck. command manually after executing *Note `mysql_upgrade': mysql-upgrade. All checked and repaired tables are marked with the current MySQL version number. This ensures that next time you run *Note `mysql_upgrade': mysql-upgrade. with the same version of the server, it can tell whether there is any need to check or repair the table again. *Note `mysql_upgrade': mysql-upgrade. also saves the MySQL version number in a file named `mysql_upgrade_info' in the data directory. This is used to quickly check whether all tables have been checked for this release so that table-checking can be skipped. To ignore this file and perform the check regardless, use the `--force' option. If you install MySQL from RPM packages on Linux, you must install the server and client RPMs. *Note `mysql_upgrade': mysql-upgrade. is included in the server RPM but requires the client RPM because the latter includes *Note `mysqlcheck': mysqlcheck. (See *Note linux-installation-rpm::.) In MySQL 5.1.7, `mysql_upgrade ' was added as a shell script and worked only for Unix systems. As of MySQL 5.1.10, *Note `mysql_upgrade': mysql-upgrade. is an executable binary and is available on all systems. *Note `mysql_upgrade': mysql-upgrade. does not upgrade the contents of the help tables. For upgrade instructions, see *Note server-side-help-support::. *Note `mysql_upgrade': mysql-upgrade. supports the following options, which can be specified on the command line or in the `[mysql_upgrade]' and `[client]' option file groups. Other options are passed to *Note `mysqlcheck': mysqlcheck. For example, it might be necessary to specify the `--password[=PASSWORD]' option. *Note `mysql_upgrade': mysql-upgrade. also supports the options for processing option files described at *Note option-file-options::. * `--help' Display a short help message and exit. * `--basedir=PATH' The path to the MySQL installation directory. This option is accepted for backward compatibility but ignored. * `--datadir=PATH' The path to the data directory. This option is accepted for backward compatibility but ignored. * `--debug-check' Print some debugging information when the program exits. This option was added in MySQL 5.1.21. * `--debug-info', `-T' Print debugging information and memory and CPU usage statistics when the program exits. This option was added in MySQL 5.1.21. * `--force' Ignore the `mysql_upgrade_info' file and force execution of *Note `mysqlcheck': mysqlcheck. even if *Note `mysql_upgrade': mysql-upgrade. has already been executed for the current version of MySQL. * `--tmpdir=PATH', `-t PATH' The path name of the directory to use for creating temporary files. This option was added in MySQL 5.1.25. * `--user=USER_NAME', `-u USER_NAME' The MySQL user name to use when connecting to the server. The default user name is `root'. * `--verbose' Verbose mode. Print more information about what the program does. * `--write-binlog' Cause binary logging to be enabled while *Note `mysql_upgrade': mysql-upgrade. runs. This is the default behavior; to disable binary logging during the upgrade, use the inverse of this option (that is, start the program with `--skip-write-binlog'). This option was introduced in MySQL 5.1.40.  File: manual.info, Node: programs-client, Next: programs-admin-utils, Prev: programs-installation, Up: programs 5.5 MySQL Client Programs ========================= * Menu: * mysql:: `mysql' --- The MySQL Command-Line Tool * mysqladmin:: `mysqladmin' --- Client for Administering a MySQL Server * mysqlcheck:: `mysqlcheck' --- A Table Maintenance Program * mysqldump:: `mysqldump' --- A Database Backup Program * mysqlimport:: `mysqlimport' --- A Data Import Program * mysqlshow:: `mysqlshow' --- Display Database, Table, and Column Information * mysqlslap:: `mysqlslap' --- Load Emulation Client This section describes client programs that connect to the MySQL server.  File: manual.info, Node: mysql, Next: mysqladmin, Prev: programs-client, Up: programs-client 5.5.1 `mysql' -- The MySQL Command-Line Tool -------------------------------------------- * Menu: * mysql-command-options:: `mysql' Options * mysql-commands:: `mysql' Commands * mysql-history-file:: `mysql' History File * mysql-server-side-help:: `mysql' Server-Side Help * batch-commands:: Executing SQL Statements from a Text File * mysql-tips:: `mysql' Tips *Note `mysql': mysql. is a simple SQL shell (with GNU `readline' capabilities). It supports interactive and noninteractive use. When used interactively, query results are presented in an ASCII-table format. When used noninteractively (for example, as a filter), the result is presented in tab-separated format. The output format can be changed using command options. If you have problems due to insufficient memory for large result sets, use the `--quick' option. This forces *Note `mysql': mysql. to retrieve results from the server a row at a time rather than retrieving the entire result set and buffering it in memory before displaying it. This is done by returning the result set using the *Note `mysql_use_result()': mysql-use-result. C API function in the client/server library rather than *Note `mysql_store_result()': mysql-store-result. Using *Note `mysql': mysql. is very easy. Invoke it from the prompt of your command interpreter as follows: shell> mysql DB_NAME Or: shell> mysql --user=USER_NAME --password=YOUR_PASSWORD DB_NAME Then type an SQL statement, end it with ``;'', `\g', or `\G' and press Enter. As of MySQL 5.1.10, typing Control+C causes *Note `mysql': mysql. to attempt to kill the current statement. If this cannot be done, or Control+C is typed again before the statement is killed, *Note `mysql': mysql. exits. Previously, Control+C caused *Note `mysql': mysql. to exit in all cases. You can execute SQL statements in a script file (batch file) like this: shell> mysql DB_NAME < SCRIPT.SQL > OUTPUT.TAB On Unix, the *Note `mysql': mysql. client writes a record of executed statements to a history file. See *Note mysql-history-file::.  File: manual.info, Node: mysql-command-options, Next: mysql-commands, Prev: mysql, Up: mysql 5.5.1.1 `mysql' Options ....................... *Note `mysql': mysql. supports the following options, which can be specified on the command line or in the `[mysql]' and `[client]' option file groups. *Note `mysql': mysql. also supports the options for processing option files described at *Note option-file-options::. *`mysql' Options* Format Option File Description IntroductionDeprecatedRemoved -auto-rehashauto-rehash Enable automatic rehashing -batch batch Don't use history file -bind-address=ip_addressbind-addressUse the specified network 5.1.22-ndb-6.3.4 interface to connect to the MySQL Server -character-sets-dir=pathcharacter-sets-dirSet the default character set -column-namescolumn-namesWrite column names in results -column-type-infocolumn-type-infoDisplay result set metadata 5.1.14 -comments comments Whether to retain or strip 5.1.23 comments in statements sent to the server -compress compress Compress all information sent between the client and the server -connect_timeout=valueconnect_timeoutThe number of seconds before connection timeout -database=dbnamedatabase The database to use -debug[=debug_options]debug Write a debugging log -debug-checkdebug-check Print debugging information 5.1.21 when the program exits -debug-info debug-info Print debugging information, memory and CPU statistics when the program exits -default-character-set=charset_namedefault-character-setUse charset_name as the default character set -delimiter=strdelimiter Set the statement delimiter -execute=statementexecute Execute the statement and quit -force force Continue even if an SQL error occurs -help Display help message and exit -host=host_namehost Connect to the MySQL server on the given host -html html Produce HTML output -ignore-spacesignore-spacesIgnore spaces after function names -line-numbersline-numbersWrite line numbers for errors -local-infile[={0|1}]local-infileEnable or disable for LOCAL capability for LOAD DATA INFILE -max_allowed_packet=valuemax_allowed_packetThe maximum packet length to send to or receive from the server -max_join_size=valuemax_join_sizeThe automatic limit for rows in a join when using -safe-updates -named-commandsnamed-commandsEnable named mysql commands -net_buffer_length=valuenet_buffer_lengthThe buffer size for TCP/IP and socket communication -no-auto-rehash Disable automatic rehashing -no-beep no-beep Do not beep when errors occur -no-named-commandsno-named-commandsDisable named mysql commands -no-pager no-pager Deprecated form of -skip-pager -no-tee no-tee Do not copy output to a file -one-databaseone-databaseIgnore statements except those for the default database named on the command line -pager[=command]pager Use the given command for paging query output -password[=password]password The password to use when connecting to the server -port=port_numport The TCP/IP port number to use for the connection -prompt=format_strprompt Set the prompt to the specified format -protocol=typeprotocol The connection protocol to use -quick quick Do not cache each query result -raw raw Write column values without escape conversion -reconnect reconnect If the connection to the server is lost, automatically try to reconnect -safe-updatessafe-updatesAllow only UPDATE and DELETE statements that specify key values -secure-authsecure-auth Do not send passwords to the server in old (pre-4.1.1) format -select_limit=valueselect_limitThe automatic limit for SELECT statements when using -safe-updates -show-warningsshow-warningsShow warnings after each statement if there are any -sigint-ignoresigint-ignoreIgnore SIGINT signals (typically the result of typing Control+C) -silent silent Silent mode -skip-auto-rehashskip-auto-rehashDisable automatic rehashing -skip-column-namesskip-column-namesDo not write column names in results -skip-line-numbersskip-line-numbersSkip line numbers for errors -skip-named-commandsskip-named-commandsDisable named mysql commands -skip-pager skip-pager Disable paging -skip-reconnectskip-reconnectDisable reconnecting -socket=pathsocket For connections to localhost -ssl-ca=file_namessl-ca The path to a file that contains a list of trusted SSL CAs -ssl-capath=directory_namessl-capath The path to a directory that contains trusted SSL CA certificates in PEM format -ssl-cert=file_namessl-cert The name of the SSL certificate file to use for establishing a secure connection -ssl-cipher=cipher_listssl-cipher A list of allowable ciphers to use for SSL encryption -ssl-key=file_namessl-key The name of the SSL key file to use for establishing a secure connection -ssl-verify-server-certssl-verify-server-certThe server's Common Name value in its certificate is verified against the host name used when connecting to the server -table table Display output in tabular format -tee=file_nametee Append a copy of output to the given file -unbuffered unbuffered Flush the buffer after each query -user=user_nameuser The MySQL user name to use when connecting to the server -verbose Verbose mode -version Display version information and exit -vertical vertical Print query output rows vertically (one line per column value) -wait wait If the connection cannot be established, wait and retry instead of aborting -xml xml Produce XML output * `--help', `-?' Display a help message and exit. * `--auto-rehash' Enable automatic rehashing. This option is on by default, which enables database, table, and column name completion. Use `--disable-auto-rehash' to disable rehashing. That causes *Note `mysql': mysql. to start faster, but you must issue the `rehash' command if you want to use name completion. To complete a name, enter the first part and press Tab. If the name is unambiguous, *Note `mysql': mysql. completes it. Otherwise, you can press Tab again to see the possible names that begin with what you have typed so far. Completion does not occur if there is no default database. * `--batch', `-B' Print results using tab as the column separator, with each row on a new line. With this option, *Note `mysql': mysql. does not use the history file. Batch mode results in nontabular output format and escaping of special characters. Escaping may be disabled by using raw mode; see the description for the `--raw' option. * `--bind-address=IP_ADDRESS' On a computer having multiple network interfaces, this option can be used to select which interface is employed when connecting to the MySQL server. This option is supported only in the version of the *Note `mysql': mysql. client that is supplied with MySQL Cluster, beginning with MySQL Cluster NDB 6.3.4. It is not available in standard MySQL 5.1 releases. * `--character-sets-dir=PATH' The directory where character sets are installed. See *Note charset-configuration::. * `--column-names' Write column names in results. * `--column-type-info', `-m' Display result set metadata. This option was added in MySQL 5.1.14. (Before that, use `--debug-info'.) The `-m' short option was added in MySQL 5.1.21. * `--comments', `-c' Whether to preserve comments in statements sent to the server. The default is -skip-comments (discard comments), enable with -comments (preserve comments). This option was added in MySQL 5.1.23. * `--compress', `-C' Compress all information sent between the client and the server if both support compression. * `--database=DB_NAME', `-D DB_NAME' The database to use. This is useful primarily in an option file. * `--debug[=DEBUG_OPTIONS]', `-# [DEBUG_OPTIONS]' Write a debugging log. A typical DEBUG_OPTIONS string is `'d:t:o,FILE_NAME''. The default is `'d:t:o,/tmp/mysql.trace''. * `--debug-check' Print some debugging information when the program exits. This option was added in MySQL 5.1.21. * `--debug-info', `-T' Before MySQL 5.1.14, this option prints debugging information and memory and CPU usage statistics when the program exits, and also causes display of result set metadata during execution. As of MySQL 5.1.14, use `--column-type-info' to display result set metadata. * `--default-character-set=CHARSET_NAME' Use CHARSET_NAME as the default character set for the client and connection. A common issue that can occur when the operating system uses `utf8' or another multi-byte character set is that output from the *Note `mysql': mysql. client is formatted incorrectly, due to the fact that the MySQL client uses the `latin1' character set by default. You can usually fix such issues by using this option to force the client to use the system character set instead. See *Note charset-configuration::, for more information. * `--delimiter=STR' Set the statement delimiter. The default is the semicolon character (``;''). * `--disable-named-commands' Disable named commands. Use the `\*' form only, or use named commands only at the beginning of a line ending with a semicolon (``;''). *Note `mysql': mysql. starts with this option _enabled_ by default. However, even with this option, long-format commands still work from the first line. See *Note mysql-commands::. * `--execute=STATEMENT', `-e STATEMENT' Execute the statement and quit. The default output format is like that produced with `--batch'. See *Note command-line-options::, for some examples. With this option, *Note `mysql': mysql. does not use the history file. * `--force', `-f' Continue even if an SQL error occurs. * `--host=HOST_NAME', `-h HOST_NAME' Connect to the MySQL server on the given host. * `--html', `-H' Produce HTML output. * `--ignore-spaces', `-i' Ignore spaces after function names. The effect of this is described in the discussion for the `IGNORE_SPACE' SQL mode (see *Note server-sql-mode::). * `--line-numbers' Write line numbers for errors. Disable this with `--skip-line-numbers'. * `--local-infile[={0|1}]' Enable or disable `LOCAL' capability for *Note `LOAD DATA INFILE': load-data. With no value, the option enables `LOCAL'. The option may be given as `--local-infile=0' or `--local-infile=1' to explicitly disable or enable `LOCAL'. Enabling `LOCAL' has no effect if the server does not also support it. * `--named-commands', `-G' Enable named *Note `mysql': mysql. commands. Long-format commands are permitted, not just short-format commands. For example, `quit' and `\q' both are recognized. Use `--skip-named-commands' to disable named commands. See *Note mysql-commands::. * `--no-auto-rehash', `-A' This has the same effect as `-skip-auto-rehash'. See the description for `--auto-rehash'. * `--no-beep', `-b' Do not beep when errors occur. * `--no-named-commands', `-g' Deprecated, use `--disable-named-commands' instead. `--no-named-commands' is removed in MySQL 5.5. * `--no-pager' Deprecated form of `--skip-pager'. See the `--pager' option. `--no-pager' is removed in MySQL 5.5. * `--no-tee' Deprecated form of `--skip-tee'. See the `--tee' option. `--no-tee' is removed in MySQL 5.5. * `--one-database', `-o' Ignore statements except those that occur while the default database is the one named on the command line. This option is rudimentary and should be used with care. Statement filtering is based only on *Note `USE': use. statements. Initially, *Note `mysql': mysql. executes statements in the input because specifying a database DB_NAME on the command line is equivalent to inserting *Note `USE DB_NAME': use. at the beginning of the input. Then, for each *Note `USE': use. statement encountered, *Note `mysql': mysql. accepts or rejects following statements depending on whether the database named is the one on the command line. The content of the statements is immaterial. Suppose that *Note `mysql': mysql. is invoked to process this set of statements: DELETE FROM db2.t2; USE db2; DROP TABLE db1.t1; CREATE TABLE db1.t1 (i INT); USE db1; INSERT INTO t1 (i) VALUES(1); CREATE TABLE db2.t1 (j INT); If the command line is *Note `mysql --force --one-database db1': mysql, *Note `mysql': mysql. handles the input as follows: * The *Note `DELETE': delete. statement is executed because the default database is `db1', even though the statement names a table in a different database. * The *Note `DROP TABLE': drop-table. and *Note `CREATE TABLE': create-table. statements are not executed because the default database is not `db1', even though the statements name a table in `db1'. * The *Note `INSERT': insert. and *Note `CREATE TABLE': create-table. statements are executed because the default database is `db1', even though the *Note `CREATE TABLE': create-table. statement names a table in a different database. * `--pager[=COMMAND]' Use the given command for paging query output. If the command is omitted, the default pager is the value of your `PAGER' environment variable. Valid pagers are `less', `more', `cat [> filename]', and so forth. This option works only on Unix and only in interactive mode. To disable paging, use `--skip-pager'. *Note mysql-commands::, discusses output paging further. * `--password[=PASSWORD]', `-p[PASSWORD]' The password to use when connecting to the server. If you use the short option form (`-p'), you _cannot_ have a space between the option and the password. If you omit the PASSWORD value following the `--password' or `-p' option on the command line, *Note `mysql': mysql. prompts for one. Specifying a password on the command line should be considered insecure. See *Note password-security-user::. You can use an option file to avoid giving the password on the command line. * `--pipe', `-W' On Windows, connect to the server using a named pipe. This option applies only if the server supports named-pipe connections. * `--port=PORT_NUM', `-P PORT_NUM' The TCP/IP port number to use for the connection. * `--prompt=FORMAT_STR' Set the prompt to the specified format. The default is `mysql>'. The special sequences that the prompt can contain are described in *Note mysql-commands::. * `--protocol={TCP|SOCKET|PIPE|MEMORY}' The connection protocol to use for connecting to the server. It is useful when the other connection parameters normally would cause a protocol to be used other than the one you want. For details on the permissible values, see *Note connecting::. * `--quick', `-q' Do not cache each query result, print each row as it is received. This may slow down the server if the output is suspended. With this option, *Note `mysql': mysql. does not use the history file. * `--raw', `-r' For tabular output, the `boxing' around columns enables one column value to be distinguished from another. For nontabular output (such as is produced in batch mode or when the `--batch' or `--silent' option is given), special characters are escaped in the output so they can be identified easily. Newline, tab, `NUL', and backslash are written as `\n', `\t', `\0', and `\\'. The `--raw' option disables this character escaping. The following example demonstrates tabular versus nontabular output and the use of raw mode to disable escaping: % mysql mysql> SELECT CHAR(92); +----------+ | CHAR(92) | +----------+ | \ | +----------+ % mysql -s mysql> SELECT CHAR(92); CHAR(92) \\ % mysql -s -r mysql> SELECT CHAR(92); CHAR(92) \ * `--reconnect' If the connection to the server is lost, automatically try to reconnect. A single reconnect attempt is made each time the connection is lost. To suppress reconnection behavior, use `--skip-reconnect'. * `--safe-updates', `--i-am-a-dummy', `-U' Permit only those *Note `UPDATE': update. and *Note `DELETE': delete. statements that specify which rows to modify by using key values. If you have set this option in an option file, you can override it by using `--safe-updates' on the command line. See *Note mysql-tips::, for more information about this option. * `--secure-auth' Do not send passwords to the server in old (pre-4.1.1) format. This prevents connections except for servers that use the newer password format. * `--show-warnings' Cause warnings to be shown after each statement if there are any. This option applies to interactive and batch mode. * `--sigint-ignore' Ignore `SIGINT' signals (typically the result of typing Control+C). * `--silent', `-s' Silent mode. Produce less output. This option can be given multiple times to produce less and less output. This option results in nontabular output format and escaping of special characters. Escaping may be disabled by using raw mode; see the description for the `--raw' option. * `--skip-column-names', `-N' Do not write column names in results. * `--skip-line-numbers', `-L' Do not write line numbers for errors. Useful when you want to compare result files that include error messages. * `--socket=PATH', `-S PATH' For connections to `localhost', the Unix socket file to use, or, on Windows, the name of the named pipe to use. * `--ssl*' Options that begin with `--ssl' specify whether to connect to the server using SSL and indicate where to find SSL keys and certificates. See *Note ssl-options::. * `--table', `-t' Display output in table format. This is the default for interactive use, but can be used to produce table output in batch mode. * `--tee=FILE_NAME' Append a copy of output to the given file. This option works only in interactive mode. *Note mysql-commands::, discusses tee files further. * `--unbuffered', `-n' Flush the buffer after each query. * `--user=USER_NAME', `-u USER_NAME' The MySQL user name to use when connecting to the server. * `--verbose', `-v' Verbose mode. Produce more output about what the program does. This option can be given multiple times to produce more and more output. (For example, `-v -v -v' produces table output format even in batch mode.) * `--version', `-V' Display version information and exit. * `--vertical', `-E' Print query output rows vertically (one line per column value). Without this option, you can specify vertical output for individual statements by terminating them with `\G'. * `--wait', `-w' If the connection cannot be established, wait and retry instead of aborting. * `--xml', `-X' Produce XML output. *Note*: Prior to MySQL 5.1.12, there was no differentiation in the output when using this option between columns containing the `NULL' value and columns containing the string literal `'NULL''; both were represented as NULL Beginning with MySQL 5.1.12, the output when `--xml' is used with *Note `mysql': mysql. matches that of *Note `mysqldump `--xml'': mysqldump. See *Note mysqldump:: for details. Beginning with MySQL 5.1.18, the XML output also uses an XML namespace, as shown here: shell> mysql --xml -uroot -e "SHOW VARIABLES LIKE 'version%'" version 5.0.40-debug version_comment Source distribution version_compile_machine i686 version_compile_os suse-linux-gnu (See Bug#25946.) You can also set the following variables by using `--VAR_NAME=VALUE'. The `--set-variable' format is deprecated and is removed in MySQL 5.5. * `connect_timeout' The number of seconds before connection timeout. (Default value is `0'.) * `max_allowed_packet' The maximum packet length to send to or receive from the server. (Default value is 16MB.) * `max_join_size' The automatic limit for rows in a join when using `--safe-updates'. (Default value is 1,000,000.) * `net_buffer_length' The buffer size for TCP/IP and socket communication. (Default value is 16KB.) * `select_limit' The automatic limit for *Note `SELECT': select. statements when using `--safe-updates'. (Default value is 1,000.)  File: manual.info, Node: mysql-commands, Next: mysql-history-file, Prev: mysql-command-options, Up: mysql 5.5.1.2 `mysql' Commands ........................ *Note `mysql': mysql. sends each SQL statement that you issue to the server to be executed. There is also a set of commands that *Note `mysql': mysql. itself interprets. For a list of these commands, type `help' or `\h' at the `mysql>' prompt: mysql> help List of all MySQL commands: Note that all text commands must be first on line and end with ';' ? (\?) Synonym for `help'. clear (\c) Clear command. connect (\r) Reconnect to the server. Optional arguments are db and host. delimiter (\d) Set statement delimiter. edit (\e) Edit command with $EDITOR. ego (\G) Send command to mysql server, display result vertically. exit (\q) Exit mysql. Same as quit. go (\g) Send command to mysql server. help (\h) Display this help. nopager (\n) Disable pager, print to stdout. notee (\t) Don't write into outfile. pager (\P) Set PAGER [to_pager]. Print the query results via PAGER. print (\p) Print current command. prompt (\R) Change your mysql prompt. quit (\q) Quit mysql. rehash (\#) Rebuild completion hash. source (\.) Execute an SQL script file. Takes a file name as an argument. status (\s) Get status information from the server. system (\!) Execute a system shell command. tee (\T) Set outfile [to_outfile]. Append everything into given outfile. use (\u) Use another database. Takes database name as argument. charset (\C) Switch to another charset. Might be needed for processing binlog with multi-byte charsets. warnings (\W) Show warnings after every statement. nowarning (\w) Don't show warnings after every statement. For server side help, type 'help contents' Each command has both a long and short form. The long form is not case sensitive; the short form is. The long form can be followed by an optional semicolon terminator, but the short form should not. The use of short-form commands within multi-line `/* ... */' comments is not supported. * `help [ARG]', `\h [ARG]', `\? [ARG]', `? [ARG]' Display a help message listing the available *Note `mysql': mysql. commands. If you provide an argument to the `help' command, *Note `mysql': mysql. uses it as a search string to access server-side help from the contents of the MySQL Reference Manual. For more information, see *Note mysql-server-side-help::. * `charset CHARSET_NAME', `\C CHARSET_NAME' Change the default character set and issue a `SET NAMES' statement. This enables the character set to remain synchronized on the client and server if *Note `mysql': mysql. is run with auto-reconnect enabled (which is not recommended), because the specified character set is used for reconnects. This command was added in MySQL 5.1.7. * `clear', `\c' Clear the current input. Use this if you change your mind about executing the statement that you are entering. * `connect [DB_NAME HOST_NAME]]', `\r [DB_NAME HOST_NAME]]' Reconnect to the server. The optional database name and host name arguments may be given to specify the default database or the host where the server is running. If omitted, the current values are used. * `delimiter STR', `\d STR' Change the string that *Note `mysql': mysql. interprets as the separator between SQL statements. The default is the semicolon character (``;''). The delimiter string can be specified as an unquoted or quoted argument on the `delimiter' command line. Quoting can be done with either single quote (`''), douple quote (`"'), or backtick (``') characters. To include a quote within a quoted string, either quote the string with a different quote character or escape the quote with a backslash (``\'') character. Backslash should be avoided outside of quoted strings because it is the escape character for MySQL. For an unquoted argument, the delimiter is read up to the first space or end of line. For a quoted argument, the delimiter is read up to the matching quote on the line. *Note `mysql': mysql. interprets instances of the delimiter string as a statement delimiter anywhere it occurs, except within quoted strings. Be careful about defining a delimiter that might occur within other words. For example, if you define the delimiter as `X', you will be unable to use the word `INDEX' in statements. *Note `mysql': mysql. interprets this as `INDE' followed by the delimiter `X'. When the delimiter recognized by *Note `mysql': mysql. is set to something other than the default of ``;'', instances of that character are sent to the server without interpretation. However, the server itself still interprets ``;'' as a statement delimiter and processes statements accordingly. This behavior on the server side comes into play for multiple-statement execution (see *Note c-api-multiple-queries::), and for parsing the body of stored procedures and functions, triggers, and events (see *Note stored-programs-defining::). * `edit', `\e' Edit the current input statement. *Note `mysql': mysql. checks the values of the `EDITOR' and `VISUAL' environment variables to determine which editor to use. The default editor is `vi' if neither variable is set. The `edit' command works only in Unix. * `ego', `\G' Send the current statement to the server to be executed and display the result using vertical format. * `exit', `\q' Exit *Note `mysql': mysql. * `go', `\g' Send the current statement to the server to be executed. * `nopager', `\n' Disable output paging. See the description for `pager'. The `nopager' command works only in Unix. * `notee', `\t' Disable output copying to the tee file. See the description for `tee'. * `nowarning', `\w' Enable display of warnings after each statement. * `pager [COMMAND]', `\P [COMMAND]' Enable output paging. By using the `--pager' option when you invoke *Note `mysql': mysql, it is possible to browse or search query results in interactive mode with Unix programs such as `less', `more', or any other similar program. If you specify no value for the option, *Note `mysql': mysql. checks the value of the `PAGER' environment variable and sets the pager to that. Pager functionality works only in interactive mode. Output paging can be enabled interactively with the `pager' command and disabled with `nopager'. The command takes an optional argument; if given, the paging program is set to that. With no argument, the pager is set to the pager that was set on the command line, or `stdout' if no pager was specified. Output paging works only in Unix because it uses the `popen()' function, which does not exist on Windows. For Windows, the `tee' option can be used instead to save query output, although it is not as convenient as `pager' for browsing output in some situations. * `print', `\p' Print the current input statement without executing it. * `prompt [STR]', `\R [STR]' Reconfigure the *Note `mysql': mysql. prompt to the given string. The special character sequences that can be used in the prompt are described later in this section. If you specify the `prompt' command with no argument, *Note `mysql': mysql. resets the prompt to the default of `mysql>'. * `quit', `\q' Exit *Note `mysql': mysql. * `rehash', `\#' Rebuild the completion hash that enables database, table, and column name completion while you are entering statements. (See the description for the `--auto-rehash' option.) * `source FILE_NAME', `\. FILE_NAME' Read the named file and executes the statements contained therein. On Windows, you can specify path name separators as `/' or `\\'. * `status', `\s' Provide status information about the connection and the server you are using. If you are running in `--safe-updates' mode, `status' also prints the values for the *Note `mysql': mysql. variables that affect your queries. * `system COMMAND', `\! COMMAND' Execute the given command using your default command interpreter. The `system' command works only in Unix. * `tee [FILE_NAME]', `\T [FILE_NAME]' By using the `--tee' option when you invoke *Note `mysql': mysql, you can log statements and their output. All the data displayed on the screen is appended into a given file. This can be very useful for debugging purposes also. *Note `mysql': mysql. flushes results to the file after each statement, just before it prints its next prompt. Tee functionality works only in interactive mode. You can enable this feature interactively with the `tee' command. Without a parameter, the previous file is used. The `tee' file can be disabled with the `notee' command. Executing `tee' again re-enables logging. * `use DB_NAME', `\u DB_NAME' Use DB_NAME as the default database. * `warnings', `\W' Enable display of warnings after each statement (if there are any). Here are a few tips about the `pager' command: * You can use it to write to a file and the results go only to the file: mysql> pager cat > /tmp/log.txt You can also pass any options for the program that you want to use as your pager: mysql> pager less -n -i -S * In the preceding example, note the `-S' option. You may find it very useful for browsing wide query results. Sometimes a very wide result set is difficult to read on the screen. The `-S' option to `less' can make the result set much more readable because you can scroll it horizontally using the left-arrow and right-arrow keys. You can also use `-S' interactively within `less' to switch the horizontal-browse mode on and off. For more information, read the `less' manual page: shell> man less * The `-F' and `-X' options may be used with `less' to cause it to exit if output fits on one screen, which is convenient when no scrolling is necessary: mysql> pager less -n -i -S -F -X * You can specify very complex pager commands for handling query output: mysql> pager cat | tee /dr1/tmp/res.txt \ | tee /dr2/tmp/res2.txt | less -n -i -S In this example, the command would send query results to two files in two different directories on two different file systems mounted on `/dr1' and `/dr2', yet still display the results onscreen using `less'. You can also combine the `tee' and `pager' functions. Have a `tee' file enabled and `pager' set to `less', and you are able to browse the results using the `less' program and still have everything appended into a file the same time. The difference between the Unix `tee' used with the `pager' command and the *Note `mysql': mysql. built-in `tee' command is that the built-in `tee' works even if you do not have the Unix `tee' available. The built-in `tee' also logs everything that is printed on the screen, whereas the Unix `tee' used with `pager' does not log quite that much. Additionally, `tee' file logging can be turned on and off interactively from within *Note `mysql': mysql. This is useful when you want to log some queries to a file, but not others. The `prompt' command reconfigures the default `mysql>' prompt. The string for defining the prompt can contain the following special sequences. Option Description `\c' A counter that increments for each statement you issue `\D' The full current date `\d' The default database `\h' The server host `\l' The current delimiter (new in 5.1.12) `\m' Minutes of the current time `\n' A newline character `\O' The current month in three-letter format (Jan, Feb, ...) `\o' The current month in numeric format `\P' am/pm `\p' The current TCP/IP port or socket file `\R' The current time, in 24-hour military time (0-23) `\r' The current time, standard 12-hour time (1-12) `\S' Semicolon `\s' Seconds of the current time `\t' A tab character `\U' Your full `USER_NAME@HOST_NAME' account name `\u' Your user name `\v' The server version `\w' The current day of the week in three-letter format (Mon, Tue, ...) `\Y' The current year, four digits `\y' The current year, two digits `\_' A space `\ ' A space (a space follows the backslash) `\'' Single quote `\"' Double quote `\\' A literal ``\'' backslash character `\X' X, for any `X' not listed above You can set the prompt in several ways: * _Use an environment variable._ You can set the `MYSQL_PS1' environment variable to a prompt string. For example: shell> export MYSQL_PS1="(\u@\h) [\d]> " * _Use a command-line option._ You can set the `--prompt' option on the command line to *Note `mysql': mysql. For example: shell> mysql --prompt="(\u@\h) [\d]> " (user@host) [database]> * _Use an option file._ You can set the `prompt' option in the `[mysql]' group of any MySQL option file, such as `/etc/my.cnf' or the `.my.cnf' file in your home directory. For example: [mysql] prompt=(\\u@\\h) [\\d]>\\_ In this example, note that the backslashes are doubled. If you set the prompt using the `prompt' option in an option file, it is advisable to double the backslashes when using the special prompt options. There is some overlap in the set of permissible prompt options and the set of special escape sequences that are recognized in option files. (The rules for escape sequences in option files are listed in *Note option-files::.) The overlap may cause you problems if you use single backslashes. For example, `\s' is interpreted as a space rather than as the current seconds value. The following example shows how to define a prompt within an option file to include the current time in `HH:MM:SS>' format: [mysql] prompt="\\r:\\m:\\s> " * _Set the prompt interactively._ You can change your prompt interactively by using the `prompt' (or `\R') command. For example: mysql> prompt (\u@\h) [\d]>\_ PROMPT set to '(\u@\h) [\d]>\_' (USER@HOST) [DATABASE]> (USER@HOST) [DATABASE]> prompt Returning to default PROMPT of mysql> mysql>  File: manual.info, Node: mysql-history-file, Next: mysql-server-side-help, Prev: mysql-commands, Up: mysql 5.5.1.3 `mysql' History File ............................ On Unix, the *Note `mysql': mysql. client writes a record of executed statements to a history file. By default, this file is named `.mysql_history' and is created in your home directory. To specify a different file, set the value of the `MYSQL_HISTFILE' environment variable. The `.mysql_history' should be protected with a restrictive access mode because sensitive information might be written to it, such as the text of SQL statements that contain passwords. See *Note password-security-user::. It is possible to suppress logging of statements to the history file by using the `--batch' or `--execute' option. If you do not want to maintain a history file, first remove `.mysql_history' if it exists, and then use either of the following techniques: * Set the `MYSQL_HISTFILE' variable to `/dev/null'. To cause this setting to take effect each time you log in, put the setting in one of your shell's startup files. * Create `.mysql_history' as a symbolic link to `/dev/null': shell> ln -s /dev/null $HOME/.mysql_history You need do this only once.  File: manual.info, Node: mysql-server-side-help, Next: batch-commands, Prev: mysql-history-file, Up: mysql 5.5.1.4 `mysql' Server-Side Help ................................ mysql> help SEARCH_STRING If you provide an argument to the `help' command, *Note `mysql': mysql. uses it as a search string to access server-side help from the contents of the MySQL Reference Manual. The proper operation of this command requires that the help tables in the `mysql' database be initialized with help topic information (see *Note server-side-help-support::). If there is no match for the search string, the search fails: mysql> help me Nothing found Please try to run 'help contents' for a list of all accessible topics Use *Note `help contents': help. to see a list of the help categories: mysql> help contents You asked for help about help category: "Contents" For more information, type 'help ', where is one of the following categories: Account Management Administration Data Definition Data Manipulation Data Types Functions Functions and Modifiers for Use with GROUP BY Geographic Features Language Structure Plugins Storage Engines Stored Routines Table Maintenance Transactions Triggers If the search string matches multiple items, *Note `mysql': mysql. shows a list of matching topics: mysql> help logs Many help items for your request exist. To make a more specific request, please type 'help ', where is one of the following topics: SHOW SHOW BINARY LOGS SHOW ENGINE SHOW LOGS Use a topic as the search string to see the help entry for that topic: mysql> help show binary logs Name: 'SHOW BINARY LOGS' Description: Syntax: SHOW BINARY LOGS SHOW MASTER LOGS Lists the binary log files on the server. This statement is used as part of the procedure described in [purge-binary-logs], that shows how to determine which logs can be purged. mysql> SHOW BINARY LOGS; +---------------+-----------+ | Log_name | File_size | +---------------+-----------+ | binlog.000015 | 724935 | | binlog.000016 | 733481 | +---------------+-----------+  File: manual.info, Node: batch-commands, Next: mysql-tips, Prev: mysql-server-side-help, Up: mysql 5.5.1.5 Executing SQL Statements from a Text File ................................................. The *Note `mysql': mysql. client typically is used interactively, like this: shell> mysql DB_NAME However, it is also possible to put your SQL statements in a file and then tell *Note `mysql': mysql. to read its input from that file. To do so, create a text file TEXT_FILE that contains the statements you wish to execute. Then invoke *Note `mysql': mysql. as shown here: shell> mysql DB_NAME < TEXT_FILE If you place a `USE DB_NAME' statement as the first statement in the file, it is unnecessary to specify the database name on the command line: shell> mysql < text_file If you are already running *Note `mysql': mysql, you can execute an SQL script file using the `source' command or `\.' command: mysql> source FILE_NAME mysql> \. FILE_NAME Sometimes you may want your script to display progress information to the user. For this you can insert statements like this: SELECT '' AS ' '; The statement shown outputs `'. You can also invoke *Note `mysql': mysql. with the `--verbose' option, which causes each statement to be displayed before the result that it produces. As of MySQL 5.1.23, *Note `mysql': mysql. ignores Unicode byte order mark (BOM) characters at the beginning of input files. Previously, it read them and sent them to the server, resulting in a syntax error. Presence of a BOM does not cause *Note `mysql': mysql. to change its default character set. To do that, invoke *Note `mysql': mysql. with an option such as `--default-character-set=utf8'. For more information about batch mode, see *Note batch-mode::.  File: manual.info, Node: mysql-tips, Prev: batch-commands, Up: mysql 5.5.1.6 `mysql' Tips .................... * Menu: * vertical-query-results:: Displaying Query Results Vertically * safe-updates:: Using the `--safe-updates' Option * mysql-reconnect:: Disabling `mysql' Auto-Reconnect This section describes some techniques that can help you use *Note `mysql': mysql. more effectively.  File: manual.info, Node: vertical-query-results, Next: safe-updates, Prev: mysql-tips, Up: mysql-tips 5.5.1.7 Displaying Query Results Vertically ........................................... Some query results are much more readable when displayed vertically, instead of in the usual horizontal table format. Queries can be displayed vertically by terminating the query with \G instead of a semicolon. For example, longer text values that include newlines often are much easier to read with vertical output: mysql> SELECT * FROM mails WHERE LENGTH(txt) < 300 LIMIT 300,1\G *************************** 1. row *************************** msg_nro: 3068 date: 2000-03-01 23:29:50 time_zone: +0200 mail_from: Monty reply: monty@no.spam.com mail_to: "Thimble Smith" sbj: UTF-8 txt: >>>>> "Thimble" == Thimble Smith writes: Thimble> Hi. I think this is a good idea. Is anyone familiar Thimble> with UTF-8 or Unicode? Otherwise, I'll put this on my Thimble> TODO list and see what happens. Yes, please do that. Regards, Monty file: inbox-jani-1 hash: 190402944 1 row in set (0.09 sec)  File: manual.info, Node: safe-updates, Next: mysql-reconnect, Prev: vertical-query-results, Up: mysql-tips 5.5.1.8 Using the `--safe-updates' Option ......................................... For beginners, a useful startup option is `--safe-updates' (or `--i-am-a-dummy', which has the same effect). It is helpful for cases when you might have issued a `DELETE FROM TBL_NAME' statement but forgotten the `WHERE' clause. Normally, such a statement deletes all rows from the table. With `--safe-updates', you can delete rows only by specifying the key values that identify them. This helps prevent accidents. When you use the `--safe-updates' option, *Note `mysql': mysql. issues the following statement when it connects to the MySQL server: SET sql_safe_updates=1, sql_select_limit=1000, sql_max_join_size=1000000; See *Note server-system-variables::. The *Note `SET': set-option. statement has the following effects: * You are not permitted to execute an *Note `UPDATE': update. or *Note `DELETE': delete. statement unless you specify a key constraint in the `WHERE' clause or provide a `LIMIT' clause (or both). For example: UPDATE TBL_NAME SET NOT_KEY_COLUMN=VAL WHERE KEY_COLUMN=VAL; UPDATE TBL_NAME SET NOT_KEY_COLUMN=VAL LIMIT 1; * The server limits all large *Note `SELECT': select. results to 1,000 rows unless the statement includes a `LIMIT' clause. * The server aborts multiple-table *Note `SELECT': select. statements that probably need to examine more than 1,000,000 row combinations. To specify limits different from 1,000 and 1,000,000, you can override the defaults by using the `--select_limit' and `--max_join_size' options: shell> mysql --safe-updates --select_limit=500 --max_join_size=10000  File: manual.info, Node: mysql-reconnect, Prev: safe-updates, Up: mysql-tips 5.5.1.9 Disabling `mysql' Auto-Reconnect ........................................ If the *Note `mysql': mysql. client loses its connection to the server while sending a statement, it immediately and automatically tries to reconnect once to the server and send the statement again. However, even if *Note `mysql': mysql. succeeds in reconnecting, your first connection has ended and all your previous session objects and settings are lost: temporary tables, the autocommit mode, and user-defined and session variables. Also, any current transaction rolls back. This behavior may be dangerous for you, as in the following example where the server was shut down and restarted between the first and second statements without you knowing it: mysql> SET @a=1; Query OK, 0 rows affected (0.05 sec) mysql> INSERT INTO t VALUES(@a); ERROR 2006: MySQL server has gone away No connection. Trying to reconnect... Connection id: 1 Current database: test Query OK, 1 row affected (1.30 sec) mysql> SELECT * FROM t; +------+ | a | +------+ | NULL | +------+ 1 row in set (0.05 sec) The `@a' user variable has been lost with the connection, and after the reconnection it is undefined. If it is important to have *Note `mysql': mysql. terminate with an error if the connection has been lost, you can start the *Note `mysql': mysql. client with the `--skip-reconnect' option. For more information about auto-reconnect and its effect on state information when a reconnection occurs, see *Note auto-reconnect::.  File: manual.info, Node: mysqladmin, Next: mysqlcheck, Prev: mysql, Up: programs-client 5.5.2 `mysqladmin' -- Client for Administering a MySQL Server ------------------------------------------------------------- *Note `mysqladmin': mysqladmin. is a client for performing administrative operations. You can use it to check the server's configuration and current status, to create and drop databases, and more. Invoke *Note `mysqladmin': mysqladmin. like this: shell> mysqladmin [OPTIONS] COMMAND [COMMAND-ARG] [COMMAND [COMMAND-ARG]] ... *Note `mysqladmin': mysqladmin. supports the following commands. Some of the commands take an argument following the command name. * `create DB_NAME' Create a new database named DB_NAME. * `debug' Tell the server to write debug information to the error log. Beginning with MySQL 5.1.12, this includes information about the Event Scheduler. See *Note events-status-info::. * `drop DB_NAME' Delete the database named DB_NAME and all its tables. * `extended-status' Display the server status variables and their values. * `flush-hosts' Flush all information in the host cache. * `flush-logs' Flush all logs. * `flush-privileges' Reload the grant tables (same as `reload'). * `flush-status' Clear status variables. * `flush-tables' Flush all tables. * `flush-threads' Flush the thread cache. * `kill ID,ID,...' Kill server threads. If multiple thread ID values are given, there must be no spaces in the list. * `old-password NEW-PASSWORD' This is like the `password' command but stores the password using the old (pre-4.1) password-hashing format. (See *Note password-hashing::.) * `password NEW-PASSWORD' Set a new password. This changes the password to NEW-PASSWORD for the account that you use with *Note `mysqladmin': mysqladmin. for connecting to the server. Thus, the next time you invoke *Note `mysqladmin': mysqladmin. (or any other client program) using the same account, you will need to specify the new password. If the NEW-PASSWORD value contains spaces or other characters that are special to your command interpreter, you need to enclose it within quotation marks. On Windows, be sure to use double quotation marks rather than single quotation marks; single quotation marks are not stripped from the password, but rather are interpreted as part of the password. For example: shell> mysqladmin password "my new password" *Caution*: Do not use this command used if the server was started with the `--skip-grant-tables' option. No password change will be applied. This is true even if you precede the `password' command with `flush-privileges' on the same command line to re-enable the grant tables because the flush operation occurs after you connect. However, you can use *Note `mysqladmin flush-privileges': mysqladmin. to re-enable the grant table and then use a separate *Note `mysqladmin password': mysqladmin. command to change the password. * `ping' Check whether the server is available. The return status from *Note `mysqladmin': mysqladmin. is 0 if the server is running, 1 if it is not. This is 0 even in case of an error such as `Access denied', because this means that the server is running but refused the connection, which is different from the server not running. * `processlist' Show a list of active server threads. This is like the output of the *Note `SHOW PROCESSLIST': show-processlist. statement. If the `--verbose' option is given, the output is like that of *Note `SHOW FULL PROCESSLIST': show-processlist. (See *Note show-processlist::.) * `reload' Reload the grant tables. * `refresh' Flush all tables and close and open log files. * `shutdown' Stop the server. * `start-slave' Start replication on a slave server. * `status' Display a short server status message. * `stop-slave' Stop replication on a slave server. * `variables' Display the server system variables and their values. * `version' Display version information from the server. All commands can be shortened to any unique prefix. For example: shell> mysqladmin proc stat +----+-------+-----------+----+---------+------+-------+------------------+ | Id | User | Host | db | Command | Time | State | Info | +----+-------+-----------+----+---------+------+-------+------------------+ | 51 | monty | localhost | | Query | 0 | | show processlist | +----+-------+-----------+----+---------+------+-------+------------------+ Uptime: 1473624 Threads: 1 Questions: 39487 Slow queries: 0 Opens: 541 Flush tables: 1 Open tables: 19 Queries per second avg: 0.0268 The *Note `mysqladmin status': mysqladmin. command result displays the following values: * `Uptime' The number of seconds the MySQL server has been running. * `Threads' The number of active threads (clients). * `Questions' The number of questions (queries) from clients since the server was started. * `Slow queries' The number of queries that have taken more than `long_query_time' seconds. See *Note slow-query-log::. * `Opens' The number of tables the server has opened. * `Flush tables' The number of `flush-*', `refresh', and `reload' commands the server has executed. * `Open tables' The number of tables that currently are open. * `Memory in use' The amount of memory allocated directly by *Note `mysqld': mysqld. This value is displayed only when MySQL has been compiled with `--with-debug=full'. * `Maximum memory used' The maximum amount of memory allocated directly by *Note `mysqld': mysqld. This value is displayed only when MySQL has been compiled with `--with-debug=full'. If you execute *Note `mysqladmin shutdown': mysqladmin. when connecting to a local server using a Unix socket file, *Note `mysqladmin': mysqladmin. waits until the server's process ID file has been removed, to ensure that the server has stopped properly. *Note `mysqladmin': mysqladmin. supports the following options, which can be specified on the command line or in the `[mysqladmin]' and `[client]' option file groups. *Note `mysqladmin': mysqladmin. also supports the options for processing option files described at *Note option-file-options::. *`mysqladmin' Options* Format Option File Description IntroductionDeprecatedRemoved -bind-address=ip_addressbind-addressUse the specified network 5.1.22-ndb-6.3.4 interface to connect to the MySQL Server -compress compress Compress all information sent between the client and the server -connect_timeout=secondsconnect_timeoutThe number of seconds before connection timeout -count=# count The number of iterations to make for repeated command execution -debug[=debug_options]debug Write a debugging log -debug-checkdebug-check Print debugging information 5.1.21 when the program exits -debug-info debug-info Print debugging information, 5.1.14 memory and CPU statistics when the program exits -default-character-set=charset_namedefault-character-setUse charset_name as the default character set -force force Continue even if an SQL error occurs -help Display help message and exit -host=host_namehost Connect to the MySQL server on the given host -no-beep no-beep Do not beep when errors occur 5.1.17 -password[=password]password The password to use when connecting to the server -pipe On Windows, connect to server using a named pipe -port=port_numport The TCP/IP port number to use for the connection -protocol=typeprotocol The connection protocol to use -relative relative Show the difference between the current and previous values when used with the -sleep option -shutdown_timeout=secondsshutdown_timeoutThe maximum number of seconds to wait for server shutdown -silent silent Silent mode -sleep=delaysleep Execute commands repeatedly, sleeping for delay seconds in between -socket=pathsocket For connections to localhost -ssl-ca=file_namessl-ca The path to a file that contains a list of trusted SSL CAs -ssl-capath=directory_namessl-capath The path to a directory that contains trusted SSL CA certificates in PEM format -ssl-cert=file_namessl-cert The name of the SSL certificate file to use for establishing a secure connection -ssl-cipher=cipher_listssl-cipher A list of allowable ciphers to use for SSL encryption -ssl-key=file_namessl-key The name of the SSL key file to use for establishing a secure connection -ssl-verify-server-certssl-verify-server-certThe server's Common Name value in its certificate is verified against the host name used when connecting to the server -user=user_name,user The MySQL user name to use when connecting to the server -verbose Verbose mode -version Display version information and exit -vertical vertical Print query output rows vertically (one line per column value) -wait wait If the connection cannot be established, wait and retry instead of aborting * `--help', `-?' Display a help message and exit. * `--bind-address=IP_ADDRESS' On a computer having multiple network interfaces, this option can be used to select which interface is employed when connecting to the MySQL server. This option is supported only in the version of *Note `mysqladmin': mysqladmin. that is supplied with MySQL Cluster, beginning with MySQL Cluster NDB 6.3.4. It is not available in standard MySQL 5.1 releases. * `--character-sets-dir=PATH' The directory where character sets are installed. See *Note charset-configuration::. * `--compress', `-C' Compress all information sent between the client and the server if both support compression. * `--count=N', `-c N' The number of iterations to make for repeated command execution if the `--sleep' option is given. * `--debug[=DEBUG_OPTIONS]', `-# [DEBUG_OPTIONS]' Write a debugging log. A typical DEBUG_OPTIONS string is `'d:t:o,FILE_NAME''. The default is `'d:t:o,/tmp/mysqladmin.trace''. * `--debug-check' Print some debugging information when the program exits. This option was added in MySQL 5.1.21. * `--debug-info' Print debugging information and memory and CPU usage statistics when the program exits. This option was added in MySQL 5.1.14. * `--default-character-set=CHARSET_NAME' Use CHARSET_NAME as the default character set. See *Note charset-configuration::. * `--force', `-f' Do not ask for confirmation for the `drop DB_NAME' command. With multiple commands, continue even if an error occurs. * `--host=HOST_NAME', `-h HOST_NAME' Connect to the MySQL server on the given host. * `--no-beep', `-b' Suppress the warning beep that is emitted by default for errors such as a failure to connect to the server. This option was added in MySQL 5.1.17. * `--password[=PASSWORD]', `-p[PASSWORD]' The password to use when connecting to the server. If you use the short option form (`-p'), you _cannot_ have a space between the option and the password. If you omit the PASSWORD value following the `--password' or `-p' option on the command line, *Note `mysqladmin': mysqladmin. prompts for one. Specifying a password on the command line should be considered insecure. See *Note password-security-user::. You can use an option file to avoid giving the password on the command line. * `--pipe', `-W' On Windows, connect to the server using a named pipe. This option applies only if the server supports named-pipe connections. * `--port=PORT_NUM', `-P PORT_NUM' The TCP/IP port number to use for the connection. * `--protocol={TCP|SOCKET|PIPE|MEMORY}' The connection protocol to use for connecting to the server. It is useful when the other connection parameters normally would cause a protocol to be used other than the one you want. For details on the permissible values, see *Note connecting::. * `--relative', `-r' Show the difference between the current and previous values when used with the `--sleep' option. This option works only with the `extended-status' command. * `--silent', `-s' Exit silently if a connection to the server cannot be established. * `--sleep=DELAY', `-i DELAY' Execute commands repeatedly, sleeping for DELAY seconds in between. The `--count' option determines the number of iterations. If `--count' is not given, *Note `mysqladmin': mysqladmin. executes commands indefinitely until interrupted. * `--socket=PATH', `-S PATH' For connections to `localhost', the Unix socket file to use, or, on Windows, the name of the named pipe to use. * `--ssl*' Options that begin with `--ssl' specify whether to connect to the server using SSL and indicate where to find SSL keys and certificates. See *Note ssl-options::. * `--user=USER_NAME', `-u USER_NAME' The MySQL user name to use when connecting to the server. * `--verbose', `-v' Verbose mode. Print more information about what the program does. * `--version', `-V' Display version information and exit. * `--vertical', `-E' Print output vertically. This is similar to `--relative', but prints output vertically. * `--wait[=COUNT]', `-w[COUNT]' If the connection cannot be established, wait and retry instead of aborting. If a COUNT value is given, it indicates the number of times to retry. The default is one time. You can also set the following variables by using `--VAR_NAME=VALUE' The `--set-variable' format is deprecated and is removed in MySQL 5.5. * `connect_timeout' The maximum number of seconds before connection timeout. The default value is 43200 (12 hours). * `shutdown_timeout' The maximum number of seconds to wait for server shutdown. The default value is 3600 (1 hour).  File: manual.info, Node: mysqlcheck, Next: mysqldump, Prev: mysqladmin, Up: programs-client 5.5.3 `mysqlcheck' -- A Table Maintenance Program ------------------------------------------------- The *Note `mysqlcheck': mysqlcheck. client performs table maintenance: It checks, repairs, optimizes, or analyzes tables. Each table is locked and therefore unavailable to other sessions while it is being processed, although for check operations, the table is locked with a `READ' lock only (see *Note lock-tables::, for more information about `READ' and `WRITE' locks). Table maintenance operations can be time-consuming, particularly for large tables. If you use the `--databases' or `--all-databases' option to process all tables in one or more databases, an invocation of *Note `mysqlcheck': mysqlcheck. might take a long time. (This is also true for *Note `mysql_upgrade': mysql-upgrade. because that program invokes *Note `mysqlcheck': mysqlcheck. to check all tables and repair them if necessary.) *Note `mysqlcheck': mysqlcheck. is similar in function to *Note `myisamchk': myisamchk, but works differently. The main operational difference is that *Note `mysqlcheck': mysqlcheck. must be used when the *Note `mysqld': mysqld. server is running, whereas *Note `myisamchk': myisamchk. should be used when it is not. The benefit of using *Note `mysqlcheck': mysqlcheck. is that you do not have to stop the server to perform table maintenance. *Note `mysqlcheck': mysqlcheck. uses the SQL statements *Note `CHECK TABLE': check-table, *Note `REPAIR TABLE': repair-table, *Note `ANALYZE TABLE': analyze-table, and *Note `OPTIMIZE TABLE': optimize-table. in a convenient way for the user. It determines which statements to use for the operation you want to perform, and then sends the statements to the server to be executed. For details about which storage engines each statement works with, see the descriptions for those statements in *Note table-maintenance-sql::. The `MyISAM' storage engine supports all four maintenance operations, so *Note `mysqlcheck': mysqlcheck. can be used to perform any of them on `MyISAM' tables. Other storage engines do not necessarily support all operations. In such cases, an error message is displayed. For example, if `test.t' is a `MEMORY' table, an attempt to check it produces this result: shell> mysqlcheck test t test.t note : The storage engine for the table doesn't support check If *Note `mysqlcheck': mysqlcheck. is unable to repair a table, see *Note rebuilding-tables:: for manual table repair strategies. This will be the case, for example, for `InnoDB' tables, which can be checked with *Note `CHECK TABLE': check-table, but not repaired with *Note `REPAIR TABLE': repair-table. The use of *Note `mysqlcheck': mysqlcheck. with partitioned tables is not supported before MySQL 5.1.27. *Caution*: It is best to make a backup of a table before performing a table repair operation; under some circumstances the operation might cause data loss. Possible causes include but are not limited to file system errors. There are three general ways to invoke *Note `mysqlcheck': mysqlcheck.: shell> mysqlcheck [OPTIONS] DB_NAME [TBL_NAME ...] shell> mysqlcheck [OPTIONS] --databases DB_NAME ... shell> mysqlcheck [OPTIONS] --all-databases If you do not name any tables following DB_NAME or if you use the `--databases' or `--all-databases' option, entire databases are checked. *Note `mysqlcheck': mysqlcheck. has a special feature compared to other client programs. The default behavior of checking tables (`--check') can be changed by renaming the binary. If you want to have a tool that repairs tables by default, you should just make a copy of *Note `mysqlcheck': mysqlcheck. named `mysqlrepair', or make a symbolic link to *Note `mysqlcheck': mysqlcheck. named `mysqlrepair'. If you invoke `mysqlrepair', it repairs tables. The names shown in the following table can be used to change *Note `mysqlcheck': mysqlcheck. default behavior. Command Meaning `mysqlrepair' The default option is `--repair' `mysqlanalyze' The default option is `--analyze' `mysqloptimize' The default option is `--optimize' *Note `mysqlcheck': mysqlcheck. supports the following options, which can be specified on the command line or in the `[mysqlcheck]' and `[client]' option file groups. *Note `mysqlcheck': mysqlcheck. also supports the options for processing option files described at *Note option-file-options::. *`mysqlcheck' Options* Format Option File Description IntroductionDeprecatedRemoved -all-databasesall-databasesCheck all tables in all databases -all-in-1 all-in-1 Execute a single statement for each database that names all the tables from that database -analyze analyze Analyze the tables -auto-repairauto-repair If a checked table is corrupted, automatically fix it -bind-address=ip_addressbind-addressUse the specified network 5.1.22-ndb-6.3.4 interface to connect to the MySQL Server -character-sets-dir=pathcharacter-sets-dirThe directory where character sets are installed -check check Check the tables for errors -check-only-changedcheck-only-changedCheck only tables that have changed since the last check -check-upgradecheck-upgradeInvoke CHECK TABLE with the 5.1.7 FOR UPGRADE option -compress compress Compress all information sent between the client and the server -databases databases Process all tables in the named databases -debug[=debug_options]debug Write a debugging log -debug-checkdebug-check Print debugging information 5.1.21 when the program exits -debug-info debug-info Print debugging information, 5.1.14 memory and CPU statistics when the program exits -default-character-set=charset_namedefault-character-setUse charset_name as the default character set -extended extended Check and repair tables -fast fast Check only tables that have not been closed properly -fix-db-namesfix-db-namesConvert database names to 5.1.7 5.1 format -fix-table-namesfix-table-namesConvert table names to 5.1 5.1.7 format -force force Continue even if an SQL error occurs -help Display help message and exit -host=host_namehost Connect to the MySQL server on the given host -medium-checkmedium-checkDo a check that is faster than an -extended operation -optimize optimize Optimize the tables -password[=password]password The password to use when connecting to the server -pipe On Windows, connect to server using a named pipe -port=port_numport The TCP/IP port number to use for the connection -protocol=typeprotocol The connection protocol to use -quick quick The fastest method of checking -repair repair Perform a repair that can fix almost anything except unique keys that are not unique -silent silent Silent mode -socket=pathsocket For connections to localhost -ssl-ca=file_namessl-ca The path to a file that contains a list of trusted SSL CAs -ssl-capath=directory_namessl-capath The path to a directory that contains trusted SSL CA certificates in PEM format -ssl-cert=file_namessl-cert The name of the SSL certificate file to use for establishing a secure connection -ssl-cipher=cipher_listssl-cipher A list of allowable ciphers to use for SSL encryption -ssl-key=file_namessl-key The name of the SSL key file to use for establishing a secure connection -ssl-verify-server-certssl-verify-server-certThe server's Common Name value in its certificate is verified against the host name used when connecting to the server -tables tables Overrides the -databases or -B option -use-frm use-frm For repair operations on MyISAM tables -user=user_name,user The MySQL user name to use when connecting to the server -verbose Verbose mode -version Display version information and exit -write-binlogwrite-binlogLog ANALYZE, OPTIMIZE, 5.1.18 REPAIR statements to binary log. -skip-write-binlog adds NO_WRITE_TO_BINLOG to these statements. * `--help', `-?' Display a help message and exit. * `--all-databases', `-A' Check all tables in all databases. This is the same as using the `--databases' option and naming all the databases on the command line. * `--all-in-1', `-1' Instead of issuing a statement for each table, execute a single statement for each database that names all the tables from that database to be processed. * `--analyze', `-a' Analyze the tables. * `--auto-repair' If a checked table is corrupted, automatically fix it. Any necessary repairs are done after all tables have been checked. * `--bind-address=IP_ADDRESS' On a computer having multiple network interfaces, this option can be used to select which interface is employed when connecting to the MySQL server. This option is supported only in the version of *Note `mysqlcheck': mysqlcheck. that is supplied with MySQL Cluster, beginning with MySQL Cluster NDB 6.3.4. It is not available in standard MySQL 5.1 releases. * `--character-sets-dir=PATH' The directory where character sets are installed. See *Note charset-configuration::. * `--check', `-c' Check the tables for errors. This is the default operation. * `--check-only-changed', `-C' Check only tables that have changed since the last check or that have not been closed properly. * `--check-upgrade', `-g' Invoke *Note `CHECK TABLE': check-table. with the `FOR UPGRADE' option to check tables for incompatibilities with the current version of the server. This option automatically enables the `--fix-db-names' and `--fix-table-names' options. `--check-upgrade' was added in MySQL 5.1.7. * `--compress' Compress all information sent between the client and the server if both support compression. * `--databases', `-B' Process all tables in the named databases. Normally, *Note `mysqlcheck': mysqlcheck. treats the first name argument on the command line as a database name and following names as table names. With this option, it treats all name arguments as database names. * `--debug[=DEBUG_OPTIONS]', `-# [DEBUG_OPTIONS]' Write a debugging log. A typical DEBUG_OPTIONS string is `'d:t:o,FILE_NAME''. The default is `'d:t:o''. * `--debug-check' Print some debugging information when the program exits. This option was added in MySQL 5.1.21. * `--debug-info' Print debugging information and memory and CPU usage statistics when the program exits. This option was added in MySQL 5.1.14. * `--default-character-set=CHARSET_NAME' Use CHARSET_NAME as the default character set. See *Note charset-configuration::. * `--extended', `-e' If you are using this option to check tables, it ensures that they are 100% consistent but takes a long time. If you are using this option to repair tables, it runs an extended repair that may not only take a long time to execute, but may produce a lot of garbage rows also! * `--fast', `-F' Check only tables that have not been closed properly. * `--fix-db-names' Convert database names to 5.1 format. Only database names that contain special characters are affected. This option was added in MySQL 5.1.7. * `--fix-table-names' Convert table names to 5.1 format. Only table names that contain special characters are affected. This option was added in MySQL 5.1.7. As of MySQL 5.1.23, this option also applies to views. * `--force', `-f' Continue even if an SQL error occurs. * `--host=HOST_NAME', `-h HOST_NAME' Connect to the MySQL server on the given host. * `--medium-check', `-m' Do a check that is faster than an `--extended' operation. This finds only 99.99% of all errors, which should be good enough in most cases. * `--optimize', `-o' Optimize the tables. * `--password[=PASSWORD]', `-p[PASSWORD]' The password to use when connecting to the server. If you use the short option form (`-p'), you _cannot_ have a space between the option and the password. If you omit the PASSWORD value following the `--password' or `-p' option on the command line, *Note `mysqlcheck': mysqlcheck. prompts for one. Specifying a password on the command line should be considered insecure. See *Note password-security-user::. You can use an option file to avoid giving the password on the command line. * `--pipe', `-W' On Windows, connect to the server using a named pipe. This option applies only if the server supports named-pipe connections. * `--port=PORT_NUM', `-P PORT_NUM' The TCP/IP port number to use for the connection. * `--protocol={TCP|SOCKET|PIPE|MEMORY}' The connection protocol to use for connecting to the server. It is useful when the other connection parameters normally would cause a protocol to be used other than the one you want. For details on the permissible values, see *Note connecting::. * `--quick', `-q' If you are using this option to check tables, it prevents the check from scanning the rows to check for incorrect links. This is the fastest check method. If you are using this option to repair tables, it tries to repair only the index tree. This is the fastest repair method. * `--repair', `-r' Perform a repair that can fix almost anything except unique keys that are not unique. * `--silent', `-s' Silent mode. Print only error messages. * `--socket=PATH', `-S PATH' For connections to `localhost', the Unix socket file to use, or, on Windows, the name of the named pipe to use. * `--ssl*' Options that begin with `--ssl' specify whether to connect to the server using SSL and indicate where to find SSL keys and certificates. See *Note ssl-options::. * `--tables' Override the `--databases' or `-B' option. All name arguments following the option are regarded as table names. * `--use-frm' For repair operations on `MyISAM' tables, get the table structure from the `.frm' file so that the table can be repaired even if the `.MYI' header is corrupted. * `--user=USER_NAME', `-u USER_NAME' The MySQL user name to use when connecting to the server. * `--verbose', `-v' Verbose mode. Print information about the various stages of program operation. * `--version', `-V' Display version information and exit. * `--write-binlog' This option is enabled by default, so that *Note `ANALYZE TABLE': analyze-table, *Note `OPTIMIZE TABLE': optimize-table, and *Note `REPAIR TABLE': repair-table. statements generated by *Note `mysqlcheck': mysqlcheck. are written to the binary log. Use `--skip-write-binlog' to cause `NO_WRITE_TO_BINLOG' to be added to the statements so that they are not logged. Use the `--skip-write-binlog' when these statements should not be sent to replication slaves or run when using the binary logs for recovery from backup. This option was added in MySQL 5.1.18.  File: manual.info, Node: mysqldump, Next: mysqlimport, Prev: mysqlcheck, Up: programs-client 5.5.4 `mysqldump' -- A Database Backup Program ---------------------------------------------- The *Note `mysqldump': mysqldump. client is a backup program originally written by Igor Romanenko. It can be used to dump a database or a collection of databases for backup or transfer to another SQL server (not necessarily a MySQL server). The dump typically contains SQL statements to create the table, populate it, or both. However, *Note `mysqldump': mysqldump. can also be used to generate files in CSV, other delimited text, or XML format. If you are doing a backup on the server and your tables all are `MyISAM' tables, consider using the *Note `mysqlhotcopy': mysqlhotcopy. instead because it can accomplish faster backups and faster restores. See *Note mysqlhotcopy::. There are three general ways to invoke *Note `mysqldump': mysqldump.: shell> mysqldump [OPTIONS] DB_NAME [TBL_NAME ...] shell> mysqldump [OPTIONS] --databases DB_NAME ... shell> mysqldump [OPTIONS] --all-databases If you do not name any tables following DB_NAME or if you use the `--databases' or `--all-databases' option, entire databases are dumped. *Note `mysqldump': mysqldump. does not dump the `INFORMATION_SCHEMA' database by default. As of MySQL 5.1.38, *Note `mysqldump': mysqldump. dumps `INFORMATION_SCHEMA' if you name it explicitly on the command line, although you must also use the `--skip-lock-tables' option. Before 5.1.38, *Note `mysqldump': mysqldump. silently ignores `INFORMATION_SCHEMA' even if you name it explicitly on the command line. In MySQL Cluster NDB 7.1.7 and later, the `ndbinfo' information database is ignored and not dumped by *Note `mysqldump': mysqldump. To see a list of the options your version of *Note `mysqldump': mysqldump. supports, execute *Note `mysqldump --help': mysqldump. Some *Note `mysqldump': mysqldump. options are shorthand for groups of other options: * Use of `--opt' is the same as specifying `--add-drop-table', `--add-locks', `--create-options', `--disable-keys', `--extended-insert', `--lock-tables', `--quick', and `--set-charset'. All of the options that `--opt' stands for also are on by default because `--opt' is on by default. * Use of `--compact' is the same as specifying `--skip-add-drop-table', `--skip-add-locks', `--skip-comments', `--skip-disable-keys', and `--skip-set-charset' options. To reverse the effect of a group option, uses its `--skip-XXX' form (`--skip-opt' or `--skip-compact'). It is also possible to select only part of the effect of a group option by following it with options that enable or disable specific features. Here are some examples: * To select the effect of `--opt' except for some features, use the `--skip' option for each feature. To disable extended inserts and memory buffering, use `--opt' `--skip-extended-insert' `--skip-quick'. (Actually, `--skip-extended-insert' `--skip-quick' is sufficient because `--opt' is on by default.) * To reverse `--opt' for all features except index disabling and table locking, use `--skip-opt' `--disable-keys' `--lock-tables'. When you selectively enable or disable the effect of a group option, order is important because options are processed first to last. For example, `--disable-keys' `--lock-tables' `--skip-opt' would not have the intended effect; it is the same as `--skip-opt' by itself. *Note `mysqldump': mysqldump. can retrieve and dump table contents row by row, or it can retrieve the entire content from a table and buffer it in memory before dumping it. Buffering in memory can be a problem if you are dumping large tables. To dump tables row by row, use the `--quick' option (or `--opt', which enables `--quick'). The `--opt' option (and hence `--quick') is enabled by default, so to enable memory buffering, use `--skip-quick'. If you are using a recent version of *Note `mysqldump': mysqldump. to generate a dump to be reloaded into a very old MySQL server, you should not use the `--opt' or `--extended-insert' option. Use `--skip-opt' instead. *Note*: *Note `mysqldump': mysqldump. from MySQL 5.1.21 cannot be used to create dumps from MySQL server 5.1.20 and older. This issue is fixed in MySQL 5.1.22. (Bug#30123) *Note `mysqldump': mysqldump. supports the following options, which can be specified on the command line or in the `[mysqldump]' and `[client]' option file groups. *Note `mysqldump': mysqldump. also supports the options for processing option files described at *Note option-file-options::. *`mysqldump' Options* Format Option File Description IntroductionDeprecatedRemoved -add-drop-databaseadd-drop-databaseAdd a DROP DATABASE statement before each CREATE DATABASE statement -add-drop-tableadd-drop-tableAdd a DROP TABLE statement before each CREATE TABLE statement -add-drop-triggeradd-drop-triggerAdd a DROP TRIGGER statement 5.1.47-ndb-7.1.8 before each CREATE TRIGGER statement -add-locks add-locks Surround each table dump with LOCK TABLES and UNLOCK TABLES statements -all-databasesall-databasesDump all tables in all databases -all-tablespacesall-tablespacesAdds to a table dump all SQL 5.1.6 statements needed to create any tablespaces used by an NDB Cluster table -allow-keywordsallow-keywordsAllow creation of column names that are keywords -bind-address=ip_addressbind-addressUse the specified network 5.1.22-ndb-6.3.4 interface to connect to the MySQL Server -comments comments Add comments to the dump file -compact compact Produce more compact output -compatible=name[,name,...]compatible Produce output that is more compatible with other database systems or with older MySQL servers -complete-insertcomplete-insertUse complete INSERT statements that include column names -create-optionscreate-optionsInclude all MySQL-specific table options in CREATE TABLE statements -databases databases Dump several databases -debug[=debug_options]debug Write a debugging log -debug-checkdebug-check Print debugging information 5.1.21 when the program exits -debug-info debug-info Print debugging information, 5.1.14 memory and CPU statistics when the program exits -default-character-set=charset_namedefault-character-setUse charset_name as the default character set -delayed-insertdelayed-insertWrite INSERT DELAYED statements rather than INSERT statements -delete-master-logsdelete-master-logsOn a master replication server, delete the binary logs after performing the dump operation -disable-keysdisable-keysFor each table, surround the INSERT statements with statements to disable and enable keys -dump-date dump-date Include dump date as "Dump 5.1.23 completed on" comment if -comments is given -events events Dump events from the dumped 5.1.8 databases -extended-insertextended-insertUse multiple-row INSERT syntax that include several VALUES lists -fields-enclosed-by=stringfields-enclosed-byThis option is used with the -tab option and has the same meaning as the corresponding clause for LOAD DATA INFILE -fields-escaped-byfields-escaped-byThis option is used with the -tab option and has the same meaning as the corresponding clause for LOAD DATA INFILE -fields-optionally-enclosed-by=stringfields-optionally-enclosed-byThis option is used with the -tab option and has the same meaning as the corresponding clause for LOAD DATA INFILE -fields-terminated-by=stringfields-terminated-byThis option is used with the -tab option and has the same meaning as the corresponding clause for LOAD DATA INFILE -first-slavefirst-slave Deprecated; use -lock-all-tables instead -flush-logs flush-logs Flush the MySQL server log files before starting the dump -flush-privilegesflush-privilegesEmit a FLUSH PRIVILEGES statement after dumping the mysql database -help Display help message and exit -hex-blob hex-blob Dump binary columns using hexadecimal notation (for example, 'abc' becomes 0x616263) -host host Host to connect to (IP address or hostname) -ignore-table=db_name.tbl_nameignore-tableDo not dump the given table -insert-ignoreinsert-ignoreWrite INSERT IGNORE statements rather than INSERT statements -lines-terminated-by=stringlines-terminated-byThis option is used with the -tab option and has the same meaning as the corresponding clause for LOAD DATA INFILE -lock-all-tableslock-all-tablesLock all tables across all databases -lock-tableslock-tables Lock all tables before dumping them -log-error=file_namelog-error Append warnings and errors 5.1.18 to the named file -master-data[=value]master-data Write the binary log file name and position to the output -max_allowed_packet=valuemax_allowed_packetThe maximum packet length to send to or receive from the server -net_buffer_length=valuenet_buffer_lengthThe buffer size for TCP/IP and socket communication -no-autocommitno-autocommitEnclose the INSERT statements for each dumped table within SET autocommit = 0 and COMMIT statements -no-create-dbno-create-dbThis option suppresses the CREATE DATABASE statements -no-create-infono-create-infoDo not write CREATE TABLE statements that re-create each dumped table -no-data no-data Do not dump table contents -no-set-namesno-set-namesSame as -skip-set-charset -no-tablespacesno-tablespacesDo not write any CREATE 5.1.14 LOGFILE GROUP or CREATE TABLESPACE statements in output -opt opt Shorthand for -add-drop-table -add-locks -create-options -disable-keys -extended-insert -lock-tables -quick -set-charset. -order-by-primaryorder-by-primaryDump each table's rows sorted by its primary key, or by its first unique index -password[=password]password The password to use when connecting to the server -pipe On Windows, connect to server using a named pipe -port=port_numport The TCP/IP port number to use for the connection -quick quick Retrieve rows for a table from the server a row at a time -quote-namesquote-names Quote identifiers within backtick characters -replace replace Write REPLACE statements 5.1.3 rather than INSERT statements -result-file=fileresult-file Direct output to a given file -routines routines Dump stored routines 5.1.2 (procedures and functions) from the dumped databases -set-charsetset-charset Add SET NAMES default_character_set to the output -single-transactionsingle-transactionThis option issues a BEGIN SQL statement before dumping data from the server -skip-add-drop-tableskip-add-drop-tableDo not add a DROP TABLE statement before each CREATE TABLE statement -skip-add-locksskip-add-locksDo not add locks -skip-commentsskip-commentsDo not add comments to the dump file -skip-compactskip-compactDo not produce more compact output -skip-disable-keysskip-disable-keysDo not disable keys -skip-extended-insertskip-extended-insertTurn off extended-insert -skip-opt skip-opt Turn off the options set by -opt -skip-quick skip-quick Do not retrieve rows for a table from the server a row at a time -skip-quote-namesskip-quote-namesDo not quote identifiers -skip-set-charsetskip-set-charsetSuppress the SET NAMES statement -skip-triggersskip-triggersDo not dump triggers -skip-tz-utcskip-tz-utc Turn off tz-utc 5.1.2 -ssl-ca=file_namessl-ca The path to a file that contains a list of trusted SSL CAs -ssl-capath=directory_namessl-capath The path to a directory that contains trusted SSL CA certificates in PEM format -ssl-cert=file_namessl-cert The name of the SSL certificate file to use for establishing a secure connection -ssl-cipher=cipher_listssl-cipher A list of allowable ciphers to use for SSL encryption -ssl-key=file_namessl-key The name of the SSL key file to use for establishing a secure connection -ssl-verify-server-certssl-verify-server-certThe server's Common Name value in its certificate is verified against the host name used when connecting to the server -tab=path tab Produce tab-separated data files -tables tables Override the -databases or -B option -triggers triggers Dump triggers for each dumped table -tz-utc tz-utc Add SET TIME_ZONE='+00:00' 5.1.2 to the dump file -user=user_nameuser The MySQL user name to use when connecting to the server -verbose Verbose mode -version Display version information and exit -where='where_condition'where Dump only rows selected by the given WHERE condition -xml xml Produce XML output * `--help', `-?' Display a help message and exit. * `--add-drop-database' Add a *Note `DROP DATABASE': drop-database. statement before each *Note `CREATE DATABASE': create-database. statement. This option is typically used in conjunction with the `--all-databases' or `--databases' option because no *Note `CREATE DATABASE': create-database. statements are written unless one of those options is specified. * `--add-drop-table' Add a *Note `DROP TABLE': drop-table. statement before each *Note `CREATE TABLE': create-table. statement. * `--add-drop-trigger' Add a *Note `DROP TRIGGER': drop-trigger. statement before each *Note `CREATE TRIGGER': create-trigger. statement. *Note*: This option is supported only by *Note `mysqldump': mysqldump. as supplied with MySQL Cluster NDB 6.3.38, MySQL Cluster NDB 7.0.19, MySQL Cluster NDB 7.1.8, and later MySQL Cluster releases. It is not available when using MySQL 5.1. * `--add-locks' Surround each table dump with *Note `LOCK TABLES': lock-tables. and *Note `UNLOCK TABLES': lock-tables. statements. This results in faster inserts when the dump file is reloaded. See *Note insert-speed::. * `--all-databases', `-A' Dump all tables in all databases. This is the same as using the `--databases' option and naming all the databases on the command line. * `--all-tablespaces', `-Y' Adds to a table dump all SQL statements needed to create any tablespaces used by an *Note `NDBCLUSTER': mysql-cluster. table. This information is not otherwise included in the output from *Note `mysqldump': mysqldump. This option is currently relevant only to MySQL Cluster tables. This option was added in MySQL 5.1.6. * `--allow-keywords' Permit creation of column names that are keywords. This works by prefixing each column name with the table name. * `--bind-address=IP_ADDRESS' On a computer having multiple network interfaces, this option can be used to select which interface is employed when connecting to the MySQL server. This option is supported only in the version of *Note `mysqldump': mysqldump. that is supplied with MySQL Cluster, beginning with MySQL Cluster NDB 6.3.4. It is not available in standard MySQL 5.1 releases. * `--character-sets-dir=PATH' The directory where character sets are installed. See *Note charset-configuration::. * `--comments', `-i' Write additional information in the dump file such as program version, server version, and host. This option is enabled by default. To suppress this additional information, use `--skip-comments'. * `--compact' Produce more compact output. This option enables the `--skip-add-drop-table', `--skip-add-locks', `--skip-comments', `--skip-disable-keys', and `--skip-set-charset' options. *Note*: Prior to MySQL 5.1.21, this option did not create valid SQL if the database dump contained views. The recreation of views requires the creation and removal of temporary tables and this option suppressed the removal of those temporary tables. As a workaround, use `--compact' with the `--add-drop-table' option and then manually adjust the dump file. * `--compatible=NAME' Produce output that is more compatible with other database systems or with older MySQL servers. The value of NAME can be `ansi', `mysql323', `mysql40', `postgresql', `oracle', `mssql', `db2', `maxdb', `no_key_options', `no_table_options', or `no_field_options'. To use several values, separate them by commas. These values have the same meaning as the corresponding options for setting the server SQL mode. See *Note server-sql-mode::. This option does not guarantee compatibility with other servers. It only enables those SQL mode values that are currently available for making dump output more compatible. For example, `--compatible=oracle' does not map data types to Oracle types or use Oracle comment syntax. _This option requires a server version of 4.1.0 or higher_. With older servers, it does nothing. * `--complete-insert', `-c' Use complete *Note `INSERT': insert. statements that include column names. * `--compress', `-C' Compress all information sent between the client and the server if both support compression. * `--create-options' Include all MySQL-specific table options in the *Note `CREATE TABLE': create-table. statements. * `--databases', `-B' Dump several databases. Normally, *Note `mysqldump': mysqldump. treats the first name argument on the command line as a database name and following names as table names. With this option, it treats all name arguments as database names. *Note `CREATE DATABASE': create-database. and *Note `USE': use. statements are included in the output before each new database. * `--debug[=DEBUG_OPTIONS]', `-# [DEBUG_OPTIONS]' Write a debugging log. A typical DEBUG_OPTIONS string is `'d:t:o,FILE_NAME''. The default value is `'d:t:o,/tmp/mysqldump.trace''. * `--debug-check' Print some debugging information when the program exits. This option was added in MySQL 5.1.21. * `--debug-info' Print debugging information and memory and CPU usage statistics when the program exits. This option was added in MySQL 5.1.14. * `--default-character-set=CHARSET_NAME' Use CHARSET_NAME as the default character set. See *Note charset-configuration::. If no character set is specified, *Note `mysqldump': mysqldump. uses `utf8', and earlier versions use `latin1'. Prior to MySQL 5.1.38, this option has no effect for output data files produced by using the `--tab' option. See the description for that option. * `--delayed-insert' Write *Note `INSERT DELAYED': insert-delayed. statements rather than *Note `INSERT': insert. statements. * `--delete-master-logs' On a master replication server, delete the binary logs by sending a *Note `PURGE BINARY LOGS': purge-binary-logs. statement to the server after performing the dump operation. This option automatically enables `--master-data'. * `--disable-keys', `-K' For each table, surround the *Note `INSERT': insert. statements with `/*!40000 ALTER TABLE TBL_NAME DISABLE KEYS */;' and `/*!40000 ALTER TABLE TBL_NAME ENABLE KEYS */;' statements. This makes loading the dump file faster because the indexes are created after all rows are inserted. This option is effective only for nonunique indexes of `MyISAM' tables. * `--dump-date' If the `--comments' option is given, *Note `mysqldump': mysqldump. produces a comment at the end of the dump of the following form: -- Dump completed on DATE However, the date causes dump files taken at different times to appear to be different, even if the data are otherwise identical. `--dump-date' and `--skip-dump-date' control whether the date is added to the comment. The default is `--dump-date' (include the date in the comment). `--skip-dump-date' suppresses date printing. This option was added in MySQL 5.1.23. * `--events', `-E' Include Event Scheduler events for the dumped databases in the output. This option was added in MySQL 5.1.8. * `--extended-insert', `-e' Use multiple-row *Note `INSERT': insert. syntax that include several `VALUES' lists. This results in a smaller dump file and speeds up inserts when the file is reloaded. * `--fields-terminated-by=...', `--fields-enclosed-by=...', `--fields-optionally-enclosed-by=...', `--fields-escaped-by=...' These options are used with the `--tab' option and have the same meaning as the corresponding `FIELDS' clauses for *Note `LOAD DATA INFILE': load-data. See *Note load-data::. * `--first-slave' Deprecated. Use `--lock-all-tables' instead. `--first-slave' is removed in MySQL 5.5. * `--flush-logs', `-F' Flush the MySQL server log files before starting the dump. This option requires the `RELOAD' privilege. If you use this option in combination with the `--all-databases' option, the logs are flushed _for each database dumped_. The exception is when using `--lock-all-tables' or `--master-data': In this case, the logs are flushed only once, corresponding to the moment that all tables are locked. If you want your dump and the log flush to happen at exactly the same moment, you should use `--flush-logs' together with either `--lock-all-tables' or `--master-data'. * `--flush-privileges' Send a *Note `FLUSH PRIVILEGES': flush. statement to the server after dumping the `mysql' database. This option should be used any time the dump contains the `mysql' database and any other database that depends on the data in the `mysql' database for proper restoration. This option was added in MySQL 5.1.12. * `--force', `-f' Continue even if an SQL error occurs during a table dump. One use for this option is to cause *Note `mysqldump': mysqldump. to continue executing even when it encounters a view that has become invalid because the definition refers to a table that has been dropped. Without `--force', *Note `mysqldump': mysqldump. exits with an error message. With `--force', *Note `mysqldump': mysqldump. prints the error message, but it also writes an SQL comment containing the view definition to the dump output and continues executing. * `--host=HOST_NAME', `-h HOST_NAME' Dump data from the MySQL server on the given host. The default host is `localhost'. * `--hex-blob' Dump binary columns using hexadecimal notation (for example, `'abc'' becomes `0x616263'). The affected data types are *Note `BINARY': binary-varbinary, *Note `VARBINARY': binary-varbinary, the *Note `BLOB': blob. types, and *Note `BIT': numeric-types. * `--ignore-table=DB_NAME.TBL_NAME' Do not dump the given table, which must be specified using both the database and table names. To ignore multiple tables, use this option multiple times. This option also can be used to ignore views. * `--insert-ignore' Write *Note `INSERT IGNORE': insert. statements rather than *Note `INSERT': insert. statements. * `--lines-terminated-by=...' This option is used with the `--tab' option and has the same meaning as the corresponding `LINES' clause for *Note `LOAD DATA INFILE': load-data. See *Note load-data::. * `--lock-all-tables', `-x' Lock all tables across all databases. This is achieved by acquiring a global read lock for the duration of the whole dump. This option automatically turns off `--single-transaction' and `--lock-tables'. * `--lock-tables', `-l' For each dumped database, lock all tables to be dumped before dumping them. The tables are locked with `READ LOCAL' to permit concurrent inserts in the case of `MyISAM' tables. For transactional tables such as `InnoDB', `--single-transaction' is a much better option than `--lock-tables' because it does not need to lock the tables at all. Because `--lock-tables' locks tables for each database separately, this option does not guarantee that the tables in the dump file are logically consistent between databases. Tables in different databases may be dumped in completely different states. * `--log-error=FILE_NAME' Log warnings and errors by appending them to the named file. The default is to do no logging. This option was added in MySQL 5.1.18. * `--master-data[=VALUE]' Use this option to dump a master replication server to produce a dump file that can be used to set up another server as a slave of the master. It causes the dump output to include a *Note `CHANGE MASTER TO': change-master-to. statement that indicates the binary log coordinates (file name and position) of the dumped server. These are the master server coordinates from which the slave should start replicating after you load the dump file into the slave. If the option value is 2, the *Note `CHANGE MASTER TO': change-master-to. statement is written as an SQL comment, and thus is informative only; it has no effect when the dump file is reloaded. If the option value is 1, the statement is not written as a comment and takes effect when the dump file is reloaded. If no option value is specified, the default value is 1. This option requires the `RELOAD' privilege and the binary log must be enabled. The `--master-data' option automatically turns off `--lock-tables'. It also turns on `--lock-all-tables', unless `--single-transaction' also is specified, in which case, a global read lock is acquired only for a short time at the beginning of the dump (see the description for `--single-transaction'). In all cases, any action on logs happens at the exact moment of the dump. It is also possible to set up a slave by dumping an existing slave of the master. To do this, use the following procedure on the existing slave: 1. Stop the slave's SQL thread and get its current status: mysql> STOP SLAVE SQL_THREAD; mysql> SHOW SLAVE STATUS; 2. From the output of the *Note `SHOW SLAVE STATUS': show-slave-status. statement, the binary log coordinates of the master server from which the new slave should start replicating are the values of the `Relay_Master_Log_File' and `Exec_Master_Log_Pos' fields. Denote those values as FILE_NAME and FILE_POS. 3. Dump the slave server: shell> mysqldump --master-data=2 --all-databases > dumpfile 4. Restart the slave: mysql> START SLAVE; 5. On the new slave, load the dump file: shell> mysql < dumpfile 6. On the new slave, set the replication coordinates to those of the master server obtained earlier: mysql> CHANGE MASTER TO -> MASTER_LOG_FILE = 'FILE_NAME', MASTER_LOG_POS = FILE_POS; The *Note `CHANGE MASTER TO': change-master-to. statement might also need other parameters, such as `MASTER_HOST' to point the slave to the correct master server host. Add any such parameters as necessary. * `--no-autocommit' Enclose the *Note `INSERT': insert. statements for each dumped table within `SET autocommit = 0' and *Note `COMMIT': commit. statements. * `--no-create-db', `-n' This option suppresses the *Note `CREATE DATABASE': create-database. statements that are otherwise included in the output if the `--databases' or `--all-databases' option is given. * `--no-create-info', `-t' Do not write *Note `CREATE TABLE': create-table. statements that re-create each dumped table. *Note*: This option does _not_ not exclude statements creating log file groups or tablespaces from *Note `mysqldump': mysqldump. output; in MySQL 5.1.14 and later, you can use the `--no-tablespaces' option for this purpose. * `--no-data', `-d' Do not write any table row information (that is, do not dump table contents). This is useful if you want to dump only the *Note `CREATE TABLE': create-table. statement for the table (for example, to create an empty copy of the table by loading the dump file). * `--no-set-names', `-N' This has the same effect as `--skip-set-charset'. * `--no-tablespaces', `-y' This option suppresses all *Note `CREATE LOGFILE GROUP': create-logfile-group. and *Note `CREATE TABLESPACE': create-tablespace. statements in the output of *Note `mysqldump': mysqldump. This option was added in MySQL 5.1.14. * `--opt' This option is shorthand. It is the same as specifying `--add-drop-table' `--add-locks' `--create-options' `--disable-keys' `--extended-insert' `--lock-tables' `--quick' `--set-charset'. It should give you a fast dump operation and produce a dump file that can be reloaded into a MySQL server quickly. _The `--opt' option is enabled by default. Use `--skip-opt' to disable it._ See the discussion at the beginning of this section for information about selectively enabling or disabling a subset of the options affected by `--opt'. * `--order-by-primary' Dump each table's rows sorted by its primary key, or by its first unique index, if such an index exists. This is useful when dumping a `MyISAM' table to be loaded into an `InnoDB' table, but will make the dump operation take considerably longer. * `--password[=PASSWORD]', `-p[PASSWORD]' The password to use when connecting to the server. If you use the short option form (`-p'), you _cannot_ have a space between the option and the password. If you omit the PASSWORD value following the `--password' or `-p' option on the command line, *Note `mysqldump': mysqldump. prompts for one. Specifying a password on the command line should be considered insecure. See *Note password-security-user::. You can use an option file to avoid giving the password on the command line. * `--pipe', `-W' On Windows, connect to the server using a named pipe. This option applies only if the server supports named-pipe connections. * `--port=PORT_NUM', `-P PORT_NUM' The TCP/IP port number to use for the connection. * `--protocol={TCP|SOCKET|PIPE|MEMORY}' The connection protocol to use for connecting to the server. It is useful when the other connection parameters normally would cause a protocol to be used other than the one you want. For details on the permissible values, see *Note connecting::. * `--quick', `-q' This option is useful for dumping large tables. It forces *Note `mysqldump': mysqldump. to retrieve rows for a table from the server a row at a time rather than retrieving the entire row set and buffering it in memory before writing it out. * `--quote-names', `-Q' Quote identifiers (such as database, table, and column names) within ```'' characters. If the `ANSI_QUOTES' SQL mode is enabled, identifiers are quoted within ``"'' characters. This option is enabled by default. It can be disabled with `--skip-quote-names', but this option should be given after any option such as `--compatible' that may enable `--quote-names'. * `--replace' Write *Note `REPLACE': replace. statements rather than *Note `INSERT': insert. statements. This option was added in MySQL 5.1.3. * `--result-file=FILE_NAME', `-r FILE_NAME' Direct output to a given file. This option should be used on Windows to prevent newline ``\n'' characters from being converted to ``\r\n'' carriage return/newline sequences. The result file is created and its previous contents overwritten, even if an error occurs while generating the dump. * `--routines', `-R' Included stored routines (procedures and functions) for the dumped databases in the output. Use of this option requires the `SELECT' privilege for the `mysql.proc' table. The output generated by using `--routines' contains *Note `CREATE PROCEDURE': create-procedure. and *Note `CREATE FUNCTION': create-function. statements to re-create the routines. However, these statements do not include attributes such as the routine creation and modification timestamps. This means that when the routines are reloaded, they will be created with the timestamps equal to the reload time. If you require routines to be re-created with their original timestamp attributes, do not use `--routines'. Instead, dump and reload the contents of the `mysql.proc' table directly, using a MySQL account that has appropriate privileges for the `mysql' database. This option was added in MySQL 5.1.2. Before that, stored routines are not dumped. Routine `DEFINER' values are not dumped until MySQL 5.1.8. This means that before 5.1.8, when routines are reloaded, they will be created with the definer set to the reloading user. If you require routines to be re-created with their original definer, dump and load the contents of the `mysql.proc' table directly as described earlier. * `--set-charset' Add `SET NAMES DEFAULT_CHARACTER_SET' to the output. This option is enabled by default. To suppress the `SET NAMES' statement, use `--skip-set-charset'. * `--single-transaction' This option sends a *Note `START TRANSACTION': commit. SQL statement to the server before dumping data. It is useful only with transactional tables such as `InnoDB', because then it dumps the consistent state of the database at the time when *Note `BEGIN': commit. was issued without blocking any applications. When using this option, you should keep in mind that only `InnoDB' tables are dumped in a consistent state. For example, any `MyISAM' or `MEMORY' tables dumped while using this option may still change state. While a `--single-transaction' dump is in process, to ensure a valid dump file (correct table contents and binary log coordinates), no other connection should use the following statements: *Note `ALTER TABLE': alter-table, *Note `CREATE TABLE': create-table, *Note `DROP TABLE': drop-table, *Note `RENAME TABLE': rename-table, *Note `TRUNCATE TABLE': truncate-table. A consistent read is not isolated from those statements, so use of them on a table to be dumped can cause the *Note `SELECT': select. that is performed by *Note `mysqldump': mysqldump. to retrieve the table contents to obtain incorrect contents or fail. The `--single-transaction' option and the `--lock-tables' option are mutually exclusive because *Note `LOCK TABLES': lock-tables. causes any pending transactions to be committed implicitly. This option is not supported for MySQL Cluster tables; the results cannot be guaranteed to be consistent due to the fact that the *Note `NDBCLUSTER': mysql-cluster. storage engine supports only the `READ_COMMITTED' transaction isolation level. You should always use *Note `NDB': mysql-cluster. backup and restore instead. To dump large tables, you should combine the `--single-transaction' option with `--quick'. * `--skip-comments' See the description for the `--comments' option. * `--skip-opt' See the description for the `--opt' option. * `--socket=PATH', `-S PATH' For connections to `localhost', the Unix socket file to use, or, on Windows, the name of the named pipe to use. * `--ssl*' Options that begin with `--ssl' specify whether to connect to the server using SSL and indicate where to find SSL keys and certificates. See *Note ssl-options::. * `--tab=PATH', `-T PATH' Produce tab-separated text-format data files. For each dumped table, *Note `mysqldump': mysqldump. creates a `TBL_NAME.sql' file that contains the *Note `CREATE TABLE': create-table. statement that creates the table, and the server writes a `TBL_NAME.txt' file that contains its data. The option value is the directory in which to write the files. *Note*: This option should be used only when *Note `mysqldump': mysqldump. is run on the same machine as the *Note `mysqld': mysqld. server. You must have the `FILE' privilege, and the server must have permission to write files in the directory that you specify. By default, the `.txt' data files are formatted using tab characters between column values and a newline at the end of each line. The format can be specified explicitly using the `--fields-XXX' and `--lines-terminated-by' options. As of MySQL 5.1.38, column values are converted to the character set specified by the `--default-character-set' option. Prior to 5.1.38 or if no such option is present, values are dumped using the `binary' character set. In effect, there is no character set conversion. If a table contains columns in several character sets, the output data file will as well and you may not be able to reload the file correctly. * `--tables' Override the `--databases' or `-B' option. *Note `mysqldump': mysqldump. regards all name arguments following the option as table names. * `--triggers' Include triggers for each dumped table in the output. This option is enabled by default; disable it with `--skip-triggers'. * `--tz-utc' This option enables *Note `TIMESTAMP': datetime. columns to be dumped and reloaded between servers in different time zones. *Note `mysqldump': mysqldump. sets its connection time zone to UTC and adds `SET TIME_ZONE='+00:00'' to the dump file. Without this option, *Note `TIMESTAMP': datetime. columns are dumped and reloaded in the time zones local to the source and destination servers, which can cause the values to change if the servers are in different time zones. `--tz-utc' also protects against changes due to daylight saving time. `--tz-utc' is enabled by default. To disable it, use `--skip-tz-utc'. This option was added in MySQL 5.1.2. * `--user=USER_NAME', `-u USER_NAME' The MySQL user name to use when connecting to the server. * `--verbose', `-v' Verbose mode. Print more information about what the program does. * `--version', `-V' Display version information and exit. * `--where='WHERE_CONDITION'', `-w 'WHERE_CONDITION'' Dump only rows selected by the given `WHERE' condition. Quotes around the condition are mandatory if it contains spaces or other characters that are special to your command interpreter. Examples: --where="user='jimf'" -w"userid>1" -w"userid<1" * `--xml', `-X' Write dump output as well-formed XML. *`NULL', `'NULL'', and Empty Values*: For a column named COLUMN_NAME, the `NULL' value, an empty string, and the string value `'NULL'' are distinguished from one another in the output generated by this option as follows. Value: XML Representation: `NULL' (_unknown value_) `' `''' (_empty string_) `' `'NULL'' (_string value_) `NULL' Beginning with MySQL 5.1.12, the output from the *Note `mysql': mysql. client when run using the `--xml' option also follows the preceding rules. (See *Note mysql-command-options::.) Beginning with MySQL 5.1.18, XML output from *Note `mysqldump': mysqldump. includes the XML namespace, as shown here: shell> mysqldump --xml -u root world City 1 Kabul AFG Kabol 1780000 ... 4079 Rafah PSE Rafah 92020 You can also set the following variables by using `--VAR_NAME=VALUE' syntax: * `max_allowed_packet' The maximum size of the buffer for client/server communication. The maximum is 1GB. * `net_buffer_length' The initial size of the buffer for client/server communication. When creating multiple-row *Note `INSERT': insert. statements (as with the `--extended-insert' or `--opt' option), *Note `mysqldump': mysqldump. creates rows up to `net_buffer_length' length. If you increase this variable, you should also ensure that the `net_buffer_length' variable in the MySQL server is at least this large. A common use of *Note `mysqldump': mysqldump. is for making a backup of an entire database: shell> mysqldump DB_NAME > BACKUP-FILE.SQL You can load the dump file back into the server like this: shell> mysql DB_NAME < BACKUP-FILE.SQL Or like this: shell> mysql -e "source /PATH-TO-BACKUP/BACKUP-FILE.SQL" DB_NAME *Note `mysqldump': mysqldump. is also very useful for populating databases by copying data from one MySQL server to another: shell> mysqldump --opt DB_NAME | mysql --host=REMOTE_HOST -C DB_NAME It is possible to dump several databases with one command: shell> mysqldump --databases DB_NAME1 [DB_NAME2 ...] > my_databases.sql To dump all databases, use the `--all-databases' option: shell> mysqldump --all-databases > all_databases.sql For `InnoDB' tables, *Note `mysqldump': mysqldump. provides a way of making an online backup: shell> mysqldump --all-databases --single-transaction > all_databases.sql This backup acquires a global read lock on all tables (using *Note `FLUSH TABLES WITH READ LOCK': flush.) at the beginning of the dump. As soon as this lock has been acquired, the binary log coordinates are read and the lock is released. If long updating statements are running when the *Note `FLUSH': flush. statement is issued, the MySQL server may get stalled until those statements finish. After that, the dump becomes lock free and does not disturb reads and writes on the tables. If the update statements that the MySQL server receives are short (in terms of execution time), the initial lock period should not be noticeable, even with many updates. For point-in-time recovery (also known as `roll-forward,' when you need to restore an old backup and replay the changes that happened since that backup), it is often useful to rotate the binary log (see *Note binary-log::) or at least know the binary log coordinates to which the dump corresponds: shell> mysqldump --all-databases --master-data=2 > all_databases.sql Or: shell> mysqldump --all-databases --flush-logs --master-data=2 > all_databases.sql The `--master-data' and `--single-transaction' options can be used simultaneously, which provides a convenient way to make an online backup suitable for use prior to point-in-time recovery if tables are stored using the `InnoDB' storage engine. For more information on making backups, see *Note backup-methods::, and *Note backup-strategy-example::. If you encounter problems backing up views, please read the section that covers restrictions on views which describes a workaround for backing up views when this fails due to insufficient privileges. See *Note view-restrictions::.  File: manual.info, Node: mysqlimport, Next: mysqlshow, Prev: mysqldump, Up: programs-client 5.5.5 `mysqlimport' -- A Data Import Program -------------------------------------------- The *Note `mysqlimport': mysqlimport. client provides a command-line interface to the *Note `LOAD DATA INFILE': load-data. SQL statement. Most options to *Note `mysqlimport': mysqlimport. correspond directly to clauses of *Note `LOAD DATA INFILE': load-data. syntax. See *Note load-data::. Invoke *Note `mysqlimport': mysqlimport. like this: shell> mysqlimport [OPTIONS] DB_NAME TEXTFILE1 [TEXTFILE2 ...] For each text file named on the command line, *Note `mysqlimport': mysqlimport. strips any extension from the file name and uses the result to determine the name of the table into which to import the file's contents. For example, files named `patient.txt', `patient.text', and `patient' all would be imported into a table named `patient'. For additional information about *Note `mysqldump': mysqldump, see *Note using-mysqldump::. *Note `mysqlimport': mysqlimport. supports the following options, which can be specified on the command line or in the `[mysqlimport]' and `[client]' option file groups. *Note `mysqlimport': mysqlimport. also supports the options for processing option files described at *Note option-file-options::. *`mysqlimport' Options* Format Option File Description IntroductionDeprecatedRemoved -bind-address=ip_addressbind-addressUse the specified network 5.1.22-ndb-6.3.4 interface to connect to the MySQL Server -columns=column_listcolumns This option takes a comma-separated list of column names as its value -compress compress Compress all information sent between the client and the server -debug[=debug_options]debug Write a debugging log -debug-checkdebug-check Print debugging information 5.1.21 when the program exits -debug-info debug-info Print debugging information, 5.1.14 memory and CPU statistics when the program exits -default-character-set=charset_namedefault-character-setUse charset_name as the default character set -delete delete Empty the table before importing the text file -fields-enclosed-by=stringfields-enclosed-byThis option has the same meaning as the corresponding clause for LOAD DATA INFILE -fields-escaped-byfields-escaped-byThis option has the same meaning as the corresponding clause for LOAD DATA INFILE -fields-optionally-enclosed-by=stringfields-optionally-enclosed-byThis option has the same meaning as the corresponding clause for LOAD DATA INFILE -fields-terminated-by=stringfields-terminated-by- This option has the same meaning as the corresponding clause for LOAD DATA INFILE -force force Continue even if an SQL error occurs -help Display help message and exit -host=host_namehost Connect to the MySQL server on the given host -ignore ignore See the description for the -replace option -ignore-lines=#ignore-linesIgnore the first N lines of the data file -lines-terminated-by=stringlines-terminated-byThis option has the same meaning as the corresponding clause for LOAD DATA INFILE -local local Read input files locally from the client host -lock-tableslock-tables Lock all tables for writing before processing any text files -low-prioritylow-priorityUse LOW_PRIORITY when loading the table. -password[=password]password The password to use when connecting to the server -pipe On Windows, connect to server using a named pipe -port=port_numport The TCP/IP port number to use for the connection -protocol=typeprotocol The connection protocol to use -replace replace The -replace and -ignore options control handling of input rows that duplicate existing rows on unique key values -silent silent Produce output only when errors occur -socket=pathsocket For connections to localhost -ssl-ca=file_namessl-ca The path to a file that contains a list of trusted SSL CAs -ssl-capath=directory_namessl-capath The path to a directory that contains trusted SSL CA certificates in PEM format -ssl-cert=file_namessl-cert The name of the SSL certificate file to use for establishing a secure connection -ssl-cipher=cipher_listssl-cipher A list of allowable ciphers to use for SSL encryption -ssl-key=file_namessl-key The name of the SSL key file to use for establishing a secure connection -ssl-verify-server-certssl-verify-server-certThe server's Common Name value in its certificate is verified against the host name used when connecting to the server -use-threads=#use-threads The number of threads for 5.1.7 parallel file-loading -user=user_name,user The MySQL user name to use when connecting to the server -verbose Verbose mode -version Display version information and exit * `--help', `-?' Display a help message and exit. * `--bind-address=IP_ADDRESS' On a computer having multiple network interfaces, this option can be used to select which interface is employed when connecting to the MySQL server. This option is supported only in the version of *Note `mysqlimport': mysqlimport. that is supplied with MySQL Cluster, beginning with MySQL Cluster NDB 6.3.4. It is not available in standard MySQL 5.1 releases. * `--character-sets-dir=PATH' The directory where character sets are installed. See *Note charset-configuration::. * `--columns=COLUMN_LIST', `-c COLUMN_LIST' This option takes a comma-separated list of column names as its value. The order of the column names indicates how to match data file columns with table columns. * `--compress', `-C' Compress all information sent between the client and the server if both support compression. * `--debug[=DEBUG_OPTIONS]', `-# [DEBUG_OPTIONS]' Write a debugging log. A typical DEBUG_OPTIONS string is `'d:t:o,FILE_NAME''. The default is `'d:t:o''. * `--debug-check' Print some debugging information when the program exits. This option was added in MySQL 5.1.21. * `--debug-info' Print debugging information and memory and CPU usage statistics when the program exits. This option was added in MySQL 5.1.14. * `--default-character-set=CHARSET_NAME' Use CHARSET_NAME as the default character set. See *Note charset-configuration::. * `--delete', `-D' Empty the table before importing the text file. * `--fields-terminated-by=...', `--fields-enclosed-by=...', `--fields-optionally-enclosed-by=...', `--fields-escaped-by=...' These options have the same meaning as the corresponding clauses for *Note `LOAD DATA INFILE': load-data. See *Note load-data::. * `--force', `-f' Ignore errors. For example, if a table for a text file does not exist, continue processing any remaining files. Without `--force', *Note `mysqlimport': mysqlimport. exits if a table does not exist. * `--host=HOST_NAME', `-h HOST_NAME' Import data to the MySQL server on the given host. The default host is `localhost'. * `--ignore', `-i' See the description for the `--replace' option. * `--ignore-lines=N' Ignore the first N lines of the data file. * `--lines-terminated-by=...' This option has the same meaning as the corresponding clause for *Note `LOAD DATA INFILE': load-data. For example, to import Windows files that have lines terminated with carriage return/linefeed pairs, use `--lines-terminated-by="\r\n"'. (You might have to double the backslashes, depending on the escaping conventions of your command interpreter.) See *Note load-data::. * `--local', `-L' Read input files locally from the client host. * `--lock-tables', `-l' Lock _all_ tables for writing before processing any text files. This ensures that all tables are synchronized on the server. * `--low-priority' Use `LOW_PRIORITY' when loading the table. This affects only storage engines that use only table-level locking (such as `MyISAM', `MEMORY', and `MERGE'). * `--password[=PASSWORD]', `-p[PASSWORD]' The password to use when connecting to the server. If you use the short option form (`-p'), you _cannot_ have a space between the option and the password. If you omit the PASSWORD value following the `--password' or `-p' option on the command line, *Note `mysqlimport': mysqlimport. prompts for one. Specifying a password on the command line should be considered insecure. See *Note password-security-user::. You can use an option file to avoid giving the password on the command line. * `--pipe', `-W' On Windows, connect to the server using a named pipe. This option applies only if the server supports named-pipe connections. * `--port=PORT_NUM', `-P PORT_NUM' The TCP/IP port number to use for the connection. * `--protocol={TCP|SOCKET|PIPE|MEMORY}' The connection protocol to use for connecting to the server. It is useful when the other connection parameters normally would cause a protocol to be used other than the one you want. For details on the permissible values, see *Note connecting::. * `--replace', `-r' The `--replace' and `--ignore' options control handling of input rows that duplicate existing rows on unique key values. If you specify `--replace', new rows replace existing rows that have the same unique key value. If you specify `--ignore', input rows that duplicate an existing row on a unique key value are skipped. If you do not specify either option, an error occurs when a duplicate key value is found, and the rest of the text file is ignored. * `--silent', `-s' Silent mode. Produce output only when errors occur. * `--socket=PATH', `-S PATH' For connections to `localhost', the Unix socket file to use, or, on Windows, the name of the named pipe to use. * `--ssl*' Options that begin with `--ssl' specify whether to connect to the server using SSL and indicate where to find SSL keys and certificates. See *Note ssl-options::. * `--user=USER_NAME', `-u USER_NAME' The MySQL user name to use when connecting to the server. * `--use-threads=N' Load files in parallel using N threads. This option was added in MySQL 5.1.7. * `--verbose', `-v' Verbose mode. Print more information about what the program does. * `--version', `-V' Display version information and exit. Here is a sample session that demonstrates use of *Note `mysqlimport': mysqlimport.: shell> mysql -e 'CREATE TABLE imptest(id INT, n VARCHAR(30))' test shell> ed a 100 Max Sydow 101 Count Dracula . w imptest.txt 32 q shell> od -c imptest.txt 0000000 1 0 0 \t M a x S y d o w \n 1 0 0000020 1 \t C o u n t D r a c u l a \n 0000040 shell> mysqlimport --local test imptest.txt test.imptest: Records: 2 Deleted: 0 Skipped: 0 Warnings: 0 shell> mysql -e 'SELECT * FROM imptest' test +------+---------------+ | id | n | +------+---------------+ | 100 | Max Sydow | | 101 | Count Dracula | +------+---------------+  File: manual.info, Node: mysqlshow, Next: mysqlslap, Prev: mysqlimport, Up: programs-client 5.5.6 `mysqlshow' -- Display Database, Table, and Column Information -------------------------------------------------------------------- The *Note `mysqlshow': mysqlshow. client can be used to quickly see which databases exist, their tables, or a table's columns or indexes. *Note `mysqlshow': mysqlshow. provides a command-line interface to several SQL *Note `SHOW': show. statements. See *Note show::. The same information can be obtained by using those statements directly. For example, you can issue them from the *Note `mysql': mysql. client program. Invoke *Note `mysqlshow': mysqlshow. like this: shell> mysqlshow [OPTIONS] [DB_NAME [TBL_NAME [COL_NAME]]] * If no database is given, a list of database names is shown. * If no table is given, all matching tables in the database are shown. * If no column is given, all matching columns and column types in the table are shown. The output displays only the names of those databases, tables, or columns for which you have some privileges. If the last argument contains shell or SQL wildcard characters (``*'', ``?'', ``%'', or ``_''), only those names that are matched by the wildcard are shown. If a database name contains any underscores, those should be escaped with a backslash (some Unix shells require two) to get a list of the proper tables or columns. ``*'' and ``?'' characters are converted into SQL ``%'' and ``_'' wildcard characters. This might cause some confusion when you try to display the columns for a table with a ``_'' in the name, because in this case, *Note `mysqlshow': mysqlshow. shows you only the table names that match the pattern. This is easily fixed by adding an extra ``%'' last on the command line as a separate argument. *Note `mysqlshow': mysqlshow. supports the following options, which can be specified on the command line or in the `[mysqlshow]' and `[client]' option file groups. *Note `mysqlshow': mysqlshow. also supports the options for processing option files described at *Note option-file-options::. *`mysqlshow' Options* Format Option File Description IntroductionDeprecatedRemoved -bind-address=ip_addressbind-addressUse the specified network 5.1.22-ndb-6.3.4 interface to connect to the MySQL Server -compress compress Compress all information sent between the client and the server -count count Show the number of rows per table -debug[=debug_options]debug Write a debugging log -debug-checkdebug-check Print debugging information 5.1.21 when the program exits -debug-info debug-info Print debugging information, 5.1.14 memory and CPU statistics when the program exits -default-character-set=charset_namedefault-character-setUse charset_name as the default character set -help Display help message and exit -host=host_namehost Connect to the MySQL server on the given host -keys keys Show table indexes -password[=password]password The password to use when connecting to the server -pipe On Windows, connect to server using a named pipe -port=port_numport The TCP/IP port number to use for the connection -protocol=typeprotocol The connection protocol to use -show-table-type Show a column indicating the table type -socket=pathsocket For connections to localhost -ssl-ca=file_namessl-ca The path to a file that contains a list of trusted SSL CAs -ssl-capath=directory_namessl-capath The path to a directory that contains trusted SSL CA certificates in PEM format -ssl-cert=file_namessl-cert The name of the SSL certificate file to use for establishing a secure connection -ssl-cipher=cipher_listssl-cipher A list of allowable ciphers to use for SSL encryption -ssl-key=file_namessl-key The name of the SSL key file to use for establishing a secure connection -ssl-verify-server-certssl-verify-server-certThe server's Common Name value in its certificate is verified against the host name used when connecting to the server -status status Display extra information about each table -user=user_name,user The MySQL user name to use when connecting to the server -verbose Verbose mode -version Display version information and exit * `--help', `-?' Display a help message and exit. * `--bind-address=IP_ADDRESS' On a computer having multiple network interfaces, this option can be used to select which interface is employed when connecting to the MySQL server. This option is supported only in the version of *Note `mysqlshow': mysqlshow. that is supplied with MySQL Cluster, beginning with MySQL Cluster NDB 6.3.4. It is not available in standard MySQL 5.1 releases. * `--character-sets-dir=PATH' The directory where character sets are installed. See *Note charset-configuration::. * `--compress', `-C' Compress all information sent between the client and the server if both support compression. * `--count' Show the number of rows per table. This can be slow for non-`MyISAM' tables. * `--debug[=DEBUG_OPTIONS]', `-# [DEBUG_OPTIONS]' Write a debugging log. A typical DEBUG_OPTIONS string is `'d:t:o,FILE_NAME''. The default is `'d:t:o''. * `--debug-check' Print some debugging information when the program exits. This option was added in MySQL 5.1.21. * `--debug-info' Print debugging information and memory and CPU usage statistics when the program exits. This option was added in MySQL 5.1.14. * `--default-character-set=CHARSET_NAME' Use CHARSET_NAME as the default character set. See *Note charset-configuration::. * `--host=HOST_NAME', `-h HOST_NAME' Connect to the MySQL server on the given host. * `--keys', `-k' Show table indexes. * `--password[=PASSWORD]', `-p[PASSWORD]' The password to use when connecting to the server. If you use the short option form (`-p'), you _cannot_ have a space between the option and the password. If you omit the PASSWORD value following the `--password' or `-p' option on the command line, *Note `mysqlshow': mysqlshow. prompts for one. Specifying a password on the command line should be considered insecure. See *Note password-security-user::. You can use an option file to avoid giving the password on the command line. * `--pipe', `-W' On Windows, connect to the server using a named pipe. This option applies only if the server supports named-pipe connections. * `--port=PORT_NUM', `-P PORT_NUM' The TCP/IP port number to use for the connection. * `--protocol={TCP|SOCKET|PIPE|MEMORY}' The connection protocol to use for connecting to the server. It is useful when the other connection parameters normally would cause a protocol to be used other than the one you want. For details on the permissible values, see *Note connecting::. * `--show-table-type', `-t' Show a column indicating the table type, as in `SHOW FULL TABLES'. The type is `BASE TABLE' or `VIEW'. * `--socket=PATH', `-S PATH' For connections to `localhost', the Unix socket file to use, or, on Windows, the name of the named pipe to use. * `--ssl*' Options that begin with `--ssl' specify whether to connect to the server using SSL and indicate where to find SSL keys and certificates. See *Note ssl-options::. * `--status', `-i' Display extra information about each table. * `--user=USER_NAME', `-u USER_NAME' The MySQL user name to use when connecting to the server. * `--verbose', `-v' Verbose mode. Print more information about what the program does. This option can be used multiple times to increase the amount of information. * `--version', `-V' Display version information and exit.  File: manual.info, Node: mysqlslap, Prev: mysqlshow, Up: programs-client 5.5.7 `mysqlslap' -- Load Emulation Client ------------------------------------------ *Note `mysqlslap': mysqlslap. is a diagnostic program designed to emulate client load for a MySQL server and to report the timing of each stage. It works as if multiple clients are accessing the server. *Note `mysqlslap': mysqlslap. is available as of MySQL 5.1.4. Invoke *Note `mysqlslap': mysqlslap. like this: shell> mysqlslap [OPTIONS] Some options such as `--create' or `--query' enable you to specify a string containing an SQL statement or a file containing statements. If you specify a file, by default it must contain one statement per line. (That is, the implicit statement delimiter is the newline character.) Use the `--delimiter' option to specify a different delimiter, which enables you to specify statements that span multiple lines or place multiple statements on a single line. You cannot include comments in a file; *Note `mysqlslap': mysqlslap. does not understand them. *Note `mysqlslap': mysqlslap. runs in three stages: 1. Create schema, table, and optionally any stored programs or data you want to using for the test. This stage uses a single client connection. 2. Run the load test. This stage can use many client connections. 3. Clean up (disconnect, drop table if specified). This stage uses a single client connection. Examples: Supply your own create and query SQL statements, with 50 clients querying and 200 selects for each: mysqlslap --delimiter=";" \ --create="CREATE TABLE a (b int);INSERT INTO a VALUES (23)" \ --query="SELECT * FROM a" --concurrency=50 --iterations=200 Let *Note `mysqlslap': mysqlslap. build the query SQL statement with a table of two *Note `INT': numeric-types. columns and three *Note `VARCHAR': char. columns. Use five clients querying 20 times each. Do not create the table or insert the data (that is, use the previous test's schema and data): mysqlslap --concurrency=5 --iterations=20 \ --number-int-cols=2 --number-char-cols=3 \ --auto-generate-sql Tell the program to load the create, insert, and query SQL statements from the specified files, where the `create.sql' file has multiple table creation statements delimited by `';'' and multiple insert statements delimited by `';''. The `--query' file will have multiple queries delimited by `';''. Run all the load statements, then run all the queries in the query file with five clients (five times each): mysqlslap --concurrency=5 \ --iterations=5 --query=query.sql --create=create.sql \ --delimiter=";" *Note `mysqlslap': mysqlslap. supports the following options, which can be specified on the command line or in the `[mysqlslap]' and `[client]' option file groups. *Note `mysqlslap': mysqlslap. also supports the options for processing option files described at *Note option-file-options::. *`mysqlslap' Options* Format Option File Description IntroductionDeprecatedRemoved -auto-generate-sqlauto-generate-sqlGenerate SQL statements automatically when they are not supplied in files or using command options -auto-generate-sql-add-autoincrementauto-generate-sql-add-autoincrementAdd AUTO_INCREMENT column to 5.1.18 automatically generated tables -auto-generate-sql-execute-number=#auto-generate-sql-execute-numberSpecify how many queries to 5.1.18 generate automatically -auto-generate-sql-guid-primaryauto-generate-sql-guid-primaryAdd a GUID-based primary key 5.1.18 to automatically generated tables -auto-generate-sql-load-type=typeauto-generate-sql-load-typeSpecify how many queries to 5.1.16 generate automatically -auto-generate-sql-secondary-indexes=#auto-generate-sql-secondary-indexesSpecify how many secondary 5.1.18 indexes to add to automatically generated tables -auto-generate-sql-unique-query-number=#auto-generate-sql-unique-query-numberHow many different queries 5.1.18 to generate for automatic tests. -auto-generate-sql-unique-write-number=#auto-generate-sql-unique-write-numberHow many different queries 5.1.18 to generate for -auto-generate-sql-write-number -auto-generate-sql-write-number=#auto-generate-sql-write-numberHow many row inserts to 5.1.16 perform on each thread -commit=# commit How many statements to 5.1.21 execute before committing. -compress compress Compress all information sent between the client and the server -concurrency=#concurrency The number of clients to simulate when issuing the SELECT statement -create=valuecreate The file or string containing the statement to use for creating the table -create-and-drop-schema=valuecreate-and-drop-schemaThe schema in which to run 5.1.57 the tests; dropped at the end of the test run -create-schema=valuecreate-schemaThe schema in which to run 5.1.5 the tests -csv=[file] csv Generate output in comma-separated values format -debug[=debug_options]debug Write a debugging log -debug-checkdebug-check Print debugging information 5.1.21 when the program exits -debug-info debug-info Print debugging information, 5.1.21 memory and CPU statistics when the program exits -delimiter=strdelimiter The delimiter to use in SQL statements -detach=# detach Detach (close and reopen) 5.1.21 each connection after each N statements -engine=engine_nameengine The storage engine to use for creating the table -help Display help message and exit -host=host_namehost Connect to the MySQL server on the given host -iterations=#iterations The number of times to run the tests -lock-directory=pathlock-directoryThe directory to use for 5.1.5 5.1.18 storing locks -number-char-cols=#number-char-colsThe number of VARCHAR columns to use if -auto-generate-sql is specified -number-int-cols=#number-int-colsThe number of INT columns to use if -auto-generate-sql is specified -number-of-queries=#number-of-queriesLimit each client to 5.1.5 approximately this number of queries -only-print only-print Do not connect to databases. 5.1.5 mysqlslap only prints what it would have done -password[=password]password The password to use when connecting to the server -pipe On Windows, connect to server using a named pipe -port=port_numport The TCP/IP port number to use for the connection -post-query=valuepost-query The file or string 5.1.18 containing the statement to execute after the tests have completed -post-system=strpost-system The string to execute using 5.1.21 system() after the tests have completed -pre-query=valuepre-query The file or string 5.1.18 containing the statement to execute before running the tests -pre-system=strpre-system The string to execute using 5.1.21 system() before running the tests -preserve-schemapreserve-schemaPreserve the schema from the 5.1.5 5.1.23 mysqlslap run -protocol=typeprotocol The connection protocol to use -query=valuequery The file or string containing the SELECT statement to use for retrieving data -silent silent Silent mode -slave slave Follow master locks for 5.1.5 5.1.18 other mysqlslap clients -socket=pathsocket For connections to localhost -ssl-ca=file_namessl-ca The path to a file that contains a list of trusted SSL CAs -ssl-capath=directory_namessl-capath The path to a directory that contains trusted SSL CA certificates in PEM format -ssl-cert=file_namessl-cert The name of the SSL certificate file to use for establishing a secure connection -ssl-cipher=cipher_listssl-cipher A list of allowable ciphers to use for SSL encryption -ssl-key=file_namessl-key The name of the SSL key file to use for establishing a secure connection -ssl-verify-server-certssl-verify-server-certThe server's Common Name value in its certificate is verified against the host name used when connecting to the server -use-threadsuse-threads On Unix, the default is to 5.1.6 5.1.18 use fork() calls -user=user_name,user The MySQL user name to use when connecting to the server -verbose Verbose mode -version Display version information and exit * `--help', `-?' Display a help message and exit. * `--auto-generate-sql', `-a' Generate SQL statements automatically when they are not supplied in files or using command options. * `--auto-generate-sql-add-autoincrement' Add an `AUTO_INCREMENT' column to automatically generated tables. This option was added in MySQL 5.1.18. * `--auto-generate-sql-execute-number=N' Specify how many queries to generate automatically. This option was added in MySQL 5.1.18. * `--auto-generate-sql-guid-primary' Add a GUID-based primary key to automatically generated tables. This option was added in MySQL 5.1.18. * `--auto-generate-sql-load-type=TYPE' Specify the test load type. The permissible values are `read' (scan tables), `write' (insert into tables), `key' (read primary keys), `update' (update primary keys), or `mixed' (half inserts, half scanning selects). The default is `mixed'. This option was added in MySQL 5.1.16. * `--auto-generate-sql-secondary-indexes=N' Specify how many secondary indexes to add to automatically generated tables. By default, none are added. This option was added in MySQL 5.1.18. * `--auto-generate-sql-unique-query-number=N' How many different queries to generate for automatic tests. For example, if you run a `key' test that performs 1000 selects, you can use this option with a value of 1000 to run 1000 unique queries, or with a value of 50 to perform 50 different selects. The default is 10. This option was added in MySQL 5.1.18. * `--auto-generate-sql-unique-write-number=N' How many different queries to generate for `--auto-generate-sql-write-number'. The default is 10. This option was added in MySQL 5.1.18. * `--auto-generate-sql-write-number=N' How many row inserts to perform on each thread. The default is 100. This option was added in MySQL 5.1.16. * `--commit=N' How many statements to execute before committing. The default is 0 (no commits are done). This option was added in MySQL 5.1.21. * `--compress', `-C' Compress all information sent between the client and the server if both support compression. * `--concurrency=N', `-c N' The number of clients to simulate when issuing the *Note `SELECT': select. statement. * `--create=VALUE' The file or string containing the statement to use for creating the table. * `--create-and-drop-schema=VALUE' The schema in which to run the tests. *Note `mysqlslap': mysqlslap. drops the schema at the end of the test run. This option was added in MySQL 5.1.57. * `--create-schema=VALUE' The schema in which to run the tests. This option was added in MySQL 5.1.5. *Note*: If the `--auto-generate-sql' option is also given, *Note `mysqlslap': mysqlslap. drops the schema at the end of the test run. To avoid this, use the `--create-and-drop-schema' option instead. * `--csv[=FILE_NAME]' Generate output in comma-separated values format. The output goes to the named file, or to the standard output if no file is given. This option was added in MySQL 5.1.5. * `--debug[=DEBUG_OPTIONS]', `-# [DEBUG_OPTIONS]' Write a debugging log. A typical DEBUG_OPTIONS string is `'d:t:o,FILE_NAME''. The default is `'d:t:o,/tmp/mysqlslap.trace''. * `--debug-check' Print some debugging information when the program exits. This option was added in MySQL 5.1.21. * `--debug-info', `-T' Print debugging information and memory and CPU usage statistics when the program exits. This option was added in MySQL 5.1.21. * `--delimiter=STR', `-F STR' The delimiter to use in SQL statements supplied in files or using command options. * `--detach=N' Detach (close and reopen) each connection after each N statements. The default is 0 (connections are not detached). This option was added in MySQL 5.1.21. * `--engine=ENGINE_NAME', `-e ENGINE_NAME' The storage engine to use for creating tables. * `--host=HOST_NAME', `-h HOST_NAME' Connect to the MySQL server on the given host. * `--iterations=N', `-i N' The number of times to run the tests. * `--lock-directory=PATH' The directory to use for storing locks. This option was added in MySQL 5.1.5 and removed in 5.1.18. * `--number-char-cols=N', `-x N' The number of *Note `VARCHAR': char. columns to use if `--auto-generate-sql' is specified. * `--number-int-cols=N', `-y N' The number of *Note `INT': numeric-types. columns to use if `--auto-generate-sql' is specified. * `--number-of-queries=N' Limit each client to approximately this many queries. Query counting takes into account the statement delimiter. For example, if you invoke *Note `mysqlslap': mysqlslap. as follows, the `;' delimiter is recognized so that each instance of the query string counts as two queries. As a result, 5 rows (not 10) are inserted. shell> mysqlslap --delimiter=";" --number-of-queries=10 --query="use test;insert into t values(null)" This option was added in MySQL 5.1.5. * `--only-print' Do not connect to databases. *Note `mysqlslap': mysqlslap. only prints what it would have done. This option was added in MySQL 5.1.5. * `--password[=PASSWORD]', `-p[PASSWORD]' The password to use when connecting to the server. If you use the short option form (`-p'), you _cannot_ have a space between the option and the password. If you omit the PASSWORD value following the `--password' or `-p' option on the command line, *Note `mysqlslap': mysqlslap. prompts for one. Specifying a password on the command line should be considered insecure. See *Note password-security-user::. You can use an option file to avoid giving the password on the command line. * `--pipe', `-W' On Windows, connect to the server using a named pipe. This option applies only if the server supports named-pipe connections. * `--port=PORT_NUM', `-P PORT_NUM' The TCP/IP port number to use for the connection. * `--post-query=VALUE' The file or string containing the statement to execute after the tests have completed. This execution is not counted for timing purposes. This option was added in MySQL 5.1.18. * `--shared-memory-base-name=NAME' On Windows, the shared-memory name to use, for connections made using shared memory to a local server. This option applies only if the server supports shared-memory connections. * `--post-system=STR' The string to execute using `system()' after the tests have completed. This execution is not counted for timing purposes. This option was added in MySQL 5.1.21. * `--pre-query=VALUE' The file or string containing the statement to execute before running the tests. This execution is not counted for timing purposes. This option was added in MySQL 5.1.18. * `--pre-system=STR' The string to execute using `system()' before running the tests. This execution is not counted for timing purposes. This option was added in MySQL 5.1.21. * `--preserve-schema' Preserve the schema from the *Note `mysqlslap': mysqlslap. run. The `--auto-generate-sql' and `--create' options disable this option. This option was added in MySQL 5.1.5 and removed in MySQL 5.1.23. * `--protocol={TCP|SOCKET|PIPE|MEMORY}' The connection protocol to use for connecting to the server. It is useful when the other connection parameters normally would cause a protocol to be used other than the one you want. For details on the permissible values, see *Note connecting::. * `--query=VALUE', `-q VALUE' The file or string containing the *Note `SELECT': select. statement to use for retrieving data. * `--silent', `-s' Silent mode. No output. * `--slave' Follow master locks for other *Note `mysqlslap': mysqlslap. clients. Use this option if you are trying to synchronize around one master server with `--lock-directory' plus NFS. This option was added in MySQL 5.1.5 and removed in 5.1.18. * `--socket=PATH', `-S PATH' For connections to `localhost', the Unix socket file to use, or, on Windows, the name of the named pipe to use. * `--ssl*' Options that begin with `--ssl' specify whether to connect to the server using SSL and indicate where to find SSL keys and certificates. See *Note ssl-options::. * `--use-threads' On Unix, the default is to use `fork()' calls and this option causes `pthread' calls to be used instead. (On Windows, the default is to use `pthread' calls and the option has no effect.) This option was added in MySQL 5.1.6 and removed in 5.1.18. * `--user=USER_NAME', `-u USER_NAME' The MySQL user name to use when connecting to the server. * `--verbose', `-v' Verbose mode. Print more information about what the program does. This option can be used multiple times to increase the amount of information. * `--version', `-V' Display version information and exit.  File: manual.info, Node: programs-admin-utils, Next: programs-development, Prev: programs-client, Up: programs 5.6 MySQL Administrative and Utility Programs ============================================= * Menu: * innochecksum:: `innochecksum' --- Offline InnoDB File Checksum Utility * myisam-ftdump:: `myisam_ftdump' --- Display Full-Text Index information * myisamchk:: `myisamchk' --- MyISAM Table-Maintenance Utility * myisamlog:: `myisamlog' --- Display MyISAM Log File Contents * myisampack:: `myisampack' --- Generate Compressed, Read-Only MyISAM Tables * mysqlaccess:: `mysqlaccess' --- Client for Checking Access Privileges * mysqlbinlog:: `mysqlbinlog' --- Utility for Processing Binary Log Files * mysqldumpslow:: `mysqldumpslow' --- Summarize Slow Query Log Files * mysqlhotcopy:: `mysqlhotcopy' --- A Database Backup Program * instance-manager:: `mysqlmanager' --- The MySQL Instance Manager * mysql-convert-table-format:: `mysql_convert_table_format' --- Convert Tables to Use a Given Storage Engine * mysql-find-rows:: `mysql_find_rows' --- Extract SQL Statements from Files * mysql-fix-extensions:: `mysql_fix_extensions' --- Normalize Table File Name Extensions * mysql-setpermission:: `mysql_setpermission' --- Interactively Set Permissions in Grant Tables * mysql-waitpid:: `mysql_waitpid' --- Kill Process and Wait for Its Termination * mysql-zap:: `mysql_zap' --- Kill Processes That Match a Pattern This section describes administrative programs and programs that perform miscellaneous utility operations.  File: manual.info, Node: innochecksum, Next: myisam-ftdump, Prev: programs-admin-utils, Up: programs-admin-utils 5.6.1 `innochecksum' -- Offline InnoDB File Checksum Utility ------------------------------------------------------------ *Note `innochecksum': innochecksum. prints checksums for `InnoDB' files. This tool reads an `InnoDB' tablespace file, calculates the checksum for each page, compares the calculated checksum to the stored checksum, and reports mismatches, which indicate damaged pages. It was originally developed to speed up verifying the integrity of tablespace files after power outages but can also be used after file copies. Because checksum mismatches will cause `InnoDB' to deliberately shut down a running server, it can be preferable to use this tool rather than waiting for a server in production usage to encounter the damaged pages. *Note `innochecksum': innochecksum. cannot be used on tablespace files that the server already has open. For such files, you should use *Note `CHECK TABLE': check-table. to check tables within the tablespace. If checksum mismatches are found, you would normally restore the tablespace from backup or start the server and attempt to use *Note `mysqldump': mysqldump. to make a backup of the tables within the tablespace. Invoke *Note `innochecksum': innochecksum. like this: shell> innochecksum [OPTIONS] FILE_NAME *Note `innochecksum': innochecksum. supports the following options. For options that refer to page numbers, the numbers are zero-based. * `-c' Print a count of the number of pages in the file. * `-d' Debug mode; prints checksums for each page. * `-e NUM' End at this page number. * `-p NUM' Check only this page number. * `-s NUM' Start at this page number. * `-v' Verbose mode; print a progress indicator every five seconds.  File: manual.info, Node: myisam-ftdump, Next: myisamchk, Prev: innochecksum, Up: programs-admin-utils 5.6.2 `myisam_ftdump' -- Display Full-Text Index information ------------------------------------------------------------ *Note `myisam_ftdump': myisam-ftdump. displays information about `FULLTEXT' indexes in `MyISAM' tables. It reads the `MyISAM' index file directly, so it must be run on the server host where the table is located. Before using *Note `myisam_ftdump': myisam-ftdump, be sure to issue a `FLUSH TABLES' statement first if the server is running. *Note `myisam_ftdump': myisam-ftdump. scans and dumps the entire index, which is not particularly fast. On the other hand, the distribution of words changes infrequently, so it need not be run often. Invoke *Note `myisam_ftdump': myisam-ftdump. like this: shell> myisam_ftdump [OPTIONS] TBL_NAME INDEX_NUM The TBL_NAME argument should be the name of a `MyISAM' table. You can also specify a table by naming its index file (the file with the `.MYI' suffix). If you do not invoke *Note `myisam_ftdump': myisam-ftdump. in the directory where the table files are located, the table or index file name must be preceded by the path name to the table's database directory. Index numbers begin with 0. Example: Suppose that the `test' database contains a table named `mytexttablel' that has the following definition: CREATE TABLE mytexttable ( id INT NOT NULL, txt TEXT NOT NULL, PRIMARY KEY (id), FULLTEXT (txt) ) ENGINE=MyISAM; The index on `id' is index 0 and the `FULLTEXT' index on `txt' is index 1. If your working directory is the `test' database directory, invoke *Note `myisam_ftdump': myisam-ftdump. as follows: shell> myisam_ftdump mytexttable 1 If the path name to the `test' database directory is `/usr/local/mysql/data/test', you can also specify the table name argument using that path name. This is useful if you do not invoke *Note `myisam_ftdump': myisam-ftdump. in the database directory: shell> myisam_ftdump /usr/local/mysql/data/test/mytexttable 1 You can use *Note `myisam_ftdump': myisam-ftdump. to generate a list of index entries in order of frequency of occurrence like this: shell> myisam_ftdump -c mytexttable 1 | sort -r *Note `myisam_ftdump': myisam-ftdump. supports the following options: * `--help', `-h' `-?' Display a help message and exit. * `--count', `-c' Calculate per-word statistics (counts and global weights). * `--dump', `-d' Dump the index, including data offsets and word weights. * `--length', `-l' Report the length distribution. * `--stats', `-s' Report global index statistics. This is the default operation if no other operation is specified. * `--verbose', `-v' Verbose mode. Print more output about what the program does.  File: manual.info, Node: myisamchk, Next: myisamlog, Prev: myisam-ftdump, Up: programs-admin-utils 5.6.3 `myisamchk' -- MyISAM Table-Maintenance Utility ----------------------------------------------------- * Menu: * myisamchk-general-options:: `myisamchk' General Options * myisamchk-check-options:: `myisamchk' Check Options * myisamchk-repair-options:: `myisamchk' Repair Options * myisamchk-other-options:: Other `myisamchk' Options * myisamchk-table-info:: Obtaining Table Information with `myisamchk' * myisamchk-memory:: `myisamchk' Memory Usage The *Note `myisamchk': myisamchk. utility gets information about your database tables or checks, repairs, or optimizes them. *Note `myisamchk': myisamchk. works with `MyISAM' tables (tables that have `.MYD' and `.MYI' files for storing data and indexes). You can also use the *Note `CHECK TABLE': check-table. and *Note `REPAIR TABLE': repair-table. statements to check and repair `MyISAM' tables. See *Note check-table::, and *Note repair-table::. The use of *Note `myisamchk': myisamchk. with partitioned tables is not supported. *Caution*: It is best to make a backup of a table before performing a table repair operation; under some circumstances the operation might cause data loss. Possible causes include but are not limited to file system errors. Invoke *Note `myisamchk': myisamchk. like this: shell> myisamchk [OPTIONS] TBL_NAME ... The OPTIONS specify what you want *Note `myisamchk': myisamchk. to do. They are described in the following sections. You can also get a list of options by invoking *Note `myisamchk --help': myisamchk. With no options, *Note `myisamchk': myisamchk. simply checks your table as the default operation. To get more information or to tell *Note `myisamchk': myisamchk. to take corrective action, specify options as described in the following discussion. TBL_NAME is the database table you want to check or repair. If you run *Note `myisamchk': myisamchk. somewhere other than in the database directory, you must specify the path to the database directory, because *Note `myisamchk': myisamchk. has no idea where the database is located. In fact, *Note `myisamchk': myisamchk. does not actually care whether the files you are working on are located in a database directory. You can copy the files that correspond to a database table into some other location and perform recovery operations on them there. You can name several tables on the *Note `myisamchk': myisamchk. command line if you wish. You can also specify a table by naming its index file (the file with the `.MYI' suffix). This enables you to specify all tables in a directory by using the pattern `*.MYI'. For example, if you are in a database directory, you can check all the `MyISAM' tables in that directory like this: shell> myisamchk *.MYI If you are not in the database directory, you can check all the tables there by specifying the path to the directory: shell> myisamchk /PATH/TO/DATABASE_DIR/*.MYI You can even check all tables in all databases by specifying a wildcard with the path to the MySQL data directory: shell> myisamchk /PATH/TO/DATADIR/*/*.MYI The recommended way to quickly check all `MyISAM' tables is: shell> myisamchk --silent --fast /PATH/TO/DATADIR/*/*.MYI If you want to check all `MyISAM' tables and repair any that are corrupted, you can use the following command: shell> myisamchk --silent --force --fast --update-state \ --key_buffer_size=64M --sort_buffer_size=64M \ --read_buffer_size=1M --write_buffer_size=1M \ /PATH/TO/DATADIR/*/*.MYI This command assumes that you have more than 64MB free. For more information about memory allocation with *Note `myisamchk': myisamchk, see *Note myisamchk-memory::. For additional information about using *Note `myisamchk': myisamchk, see *Note myisam-table-maintenance::. *Important*: _You must ensure that no other program is using the tables while you are running *Note `myisamchk': myisamchk._. The most effective means of doing so is to shut down the MySQL server while running *Note `myisamchk': myisamchk, or to lock all tables that *Note `myisamchk': myisamchk. is being used on. Otherwise, when you run *Note `myisamchk': myisamchk, it may display the following error message: warning: clients are using or haven't closed the table properly This means that you are trying to check a table that has been updated by another program (such as the *Note `mysqld': mysqld. server) that hasn't yet closed the file or that has died without closing the file properly, which can sometimes lead to the corruption of one or more `MyISAM' tables. If *Note `mysqld': mysqld. is running, you must force it to flush any table modifications that are still buffered in memory by using *Note `FLUSH TABLES': flush. You should then ensure that no one is using the tables while you are running *Note `myisamchk': myisamchk. However, the easiest way to avoid this problem is to use *Note `CHECK TABLE': check-table. instead of *Note `myisamchk': myisamchk. to check tables. See *Note check-table::. *Note `myisamchk': myisamchk. supports the following options, which can be specified on the command line or in the `[myisamchk]' option file group. *Note `myisamchk': myisamchk. also supports the options for processing option files described at *Note option-file-options::. *`myisamchk' Options* Format Option File Description IntroductionDeprecatedRemoved -analyze analyze Analyze the distribution of key values -backup backup Make a backup of the .MYD file as file_name-time.BAK -block-search=offsetblock-searchFind the record that a block at the given offset belongs to -check check Check the table for errors -check-only-changedcheck-only-changedCheck only tables that have changed since the last check -correct-checksumcorrect-checksumCorrect the checksum information for the table -data-file-length=lendata-file-lengthMaximum length of the data file (when re-creating data file when it is full) -debug[=debug_options]debug Write a debugging log decode_bits=#decode_bits Decode_bits -descriptiondescription Print some descriptive information about the table -extend-checkextend-checkDo a repair that tries to recover every possible row from the data file -extended-checkextended-checkCheck the table very thoroughly -fast fast Check only tables that haven't been closed properly -force force Do a repair operation automatically if myisamchk finds any errors in the table -force force-recoverOverwrite old temporary files. For use with the -r or -o option ft_max_word_len=#ft_max_word_lenMaximum word length for FULLTEXT indexes ft_min_word_len=#ft_min_word_lenMinimum word length for FULLTEXT indexes ft_stopword_file=valueft_stopword_fileUse stopwords from this file instead of built-in list -HELP Display help message and exit -help Display help message and exit -informationinformation Print informational statistics about the table that is checked key_buffer_size=#key_buffer_sizeThe size of the buffer used for index blocks for MyISAM tables -keys-used=valkeys-used A bit-value that indicates which indexes to update -max-record-length=lenmax-record-lengthSkip rows larger than the given length if myisamchk cannot allocate memory to hold them -medium-checkmedium-checkDo a check that is faster than an -extend-check operation myisam_block_size=#myisam_block_sizeBlock size to be used for MyISAM index pages -parallel-recoverparallel-recoverUses the same technique as -r and -n, but creates all the keys in parallel, using different threads (beta) -quick quick Achieve a faster repair by not modifying the data file. read_buffer_size=#read_buffer_sizeEach thread that does a sequential scan allocates a buffer of this size for each table it scans -read-only read-only Don't mark the table as checked -recover recover Do a repair that can fix almost any problem except unique keys that aren't unique -safe-recoversafe-recoverDo a repair using an old recovery method that reads through all rows in order and updates all index trees based on the rows found -set-auto-increment[=value]set-auto-incrementForce AUTO_INCREMENT numbering for new records to start at the given value -set-collation=nameset-collationSpecify the collation to use for sorting table indexes -silent silent Silent mode sort_buffer_size=#sort_buffer_sizeThe buffer that is allocated when sorting the index when doing a REPAIR or when creating indexes with CREATE INDEX or ALTER TABLE -sort-index sort-index Sort the index tree blocks in high-low order sort_key_blocks=#sort_key_blockssort_key_blocks -sort-records=#sort-recordsSort records according to a particular index -sort-recoversort-recoverForce myisamchk to use sorting to resolve the keys even if the temporary files would be very large stats_method=valuestats_methodSpecifies how MyISAM index statistics collection code should treat NULLs -tmpdir=pathtmpdir Path of the directory to be used for storing temporary files -unpack unpack Unpack a table that was packed with myisampack -update-stateupdate-stateStore information in the .MYI file to indicate when the table was checked and whether the table crashed -verbose Verbose mode -version Display version information and exit write_buffer_size=#write_buffer_sizeWrite buffer size  File: manual.info, Node: myisamchk-general-options, Next: myisamchk-check-options, Prev: myisamchk, Up: myisamchk 5.6.3.1 `myisamchk' General Options ................................... The options described in this section can be used for any type of table maintenance operation performed by *Note `myisamchk': myisamchk. The sections following this one describe options that pertain only to specific operations, such as table checking or repairing. * `--help', `-?' Display a help message and exit. Options are grouped by type of operation. * `--HELP', `-H' Display a help message and exit. Options are presented in a single list. * `--debug=DEBUG_OPTIONS', `-# DEBUG_OPTIONS' Write a debugging log. A typical DEBUG_OPTIONS string is `'d:t:o,FILE_NAME''. The default is `'d:t:o,/tmp/myisamchk.trace''. * `--silent', `-s' Silent mode. Write output only when errors occur. You can use `-s' twice (`-ss') to make *Note `myisamchk': myisamchk. very silent. * `--verbose', `-v' Verbose mode. Print more information about what the program does. This can be used with `-d' and `-e'. Use `-v' multiple times (`-vv', `-vvv') for even more output. * `--version', `-V' Display version information and exit. * `--wait', `-w' Instead of terminating with an error if the table is locked, wait until the table is unlocked before continuing. If you are running *Note `mysqld': mysqld. with external locking disabled, the table can be locked only by another *Note `myisamchk': myisamchk. command. You can also set the following variables by using `--VAR_NAME=VALUE' syntax: Variable Default Value `decode_bits' 9 `ft_max_word_len' version-dependent `ft_min_word_len' 4 `ft_stopword_file' built-in list `key_buffer_size' 523264 `myisam_block_size' 1024 `read_buffer_size' 262136 `sort_buffer_size' 2097144 `sort_key_blocks' 16 `stats_method' nulls_unequal `write_buffer_size' 262136 The possible *Note `myisamchk': myisamchk. variables and their default values can be examined with *Note `myisamchk --help': myisamchk.: `sort_buffer_size' is used when the keys are repaired by sorting keys, which is the normal case when you use `--recover'. `key_buffer_size' is used when you are checking the table with `--extend-check' or when the keys are repaired by inserting keys row by row into the table (like when doing normal inserts). Repairing through the key buffer is used in the following cases: * You use `--safe-recover'. * The temporary files needed to sort the keys would be more than twice as big as when creating the key file directly. This is often the case when you have large key values for *Note `CHAR': char, *Note `VARCHAR': char, or *Note `TEXT': blob. columns, because the sort operation needs to store the complete key values as it proceeds. If you have lots of temporary space and you can force *Note `myisamchk': myisamchk. to repair by sorting, you can use the `--sort-recover' option. Repairing through the key buffer takes much less disk space than using sorting, but is also much slower. If you want a faster repair, set the `key_buffer_size' and `sort_buffer_size' variables to about 25% of your available memory. You can set both variables to large values, because only one of them is used at a time. `myisam_block_size' is the size used for index blocks. `stats_method' influences how `NULL' values are treated for index statistics collection when the `--analyze' option is given. It acts like the `myisam_stats_method' system variable. For more information, see the description of `myisam_stats_method' in *Note server-system-variables::, and *Note myisam-index-statistics::. `ft_min_word_len' and `ft_max_word_len' indicate the minimum and maximum word length for `FULLTEXT' indexes. `ft_stopword_file' names the stopword file. These need to be set under the following circumstances. If you use *Note `myisamchk': myisamchk. to perform an operation that modifies table indexes (such as repair or analyze), the `FULLTEXT' indexes are rebuilt using the default full-text parameter values for minimum and maximum word length and the stopword file unless you specify otherwise. This can result in queries failing. The problem occurs because these parameters are known only by the server. They are not stored in `MyISAM' index files. To avoid the problem if you have modified the minimum or maximum word length or the stopword file in the server, specify the same `ft_min_word_len', `ft_max_word_len', and `ft_stopword_file' values to *Note `myisamchk': myisamchk. that you use for *Note `mysqld': mysqld. For example, if you have set the minimum word length to 3, you can repair a table with *Note `myisamchk': myisamchk. like this: shell> myisamchk --recover --ft_min_word_len=3 TBL_NAME.MYI To ensure that *Note `myisamchk': myisamchk. and the server use the same values for full-text parameters, you can place each one in both the `[mysqld]' and `[myisamchk]' sections of an option file: [mysqld] ft_min_word_len=3 [myisamchk] ft_min_word_len=3 An alternative to using *Note `myisamchk': myisamchk. is to use the *Note `REPAIR TABLE': repair-table, *Note `ANALYZE TABLE': analyze-table, *Note `OPTIMIZE TABLE': optimize-table, or *Note `ALTER TABLE': alter-table. These statements are performed by the server, which knows the proper full-text parameter values to use.  File: manual.info, Node: myisamchk-check-options, Next: myisamchk-repair-options, Prev: myisamchk-general-options, Up: myisamchk 5.6.3.2 `myisamchk' Check Options ................................. *Note `myisamchk': myisamchk. supports the following options for table checking operations: * `--check', `-c' Check the table for errors. This is the default operation if you specify no option that selects an operation type explicitly. * `--check-only-changed', `-C' Check only tables that have changed since the last check. * `--extend-check', `-e' Check the table very thoroughly. This is quite slow if the table has many indexes. This option should only be used in extreme cases. Normally, *Note `myisamchk': myisamchk. or *Note `myisamchk --medium-check': myisamchk. should be able to determine whether there are any errors in the table. If you are using `--extend-check' and have plenty of memory, setting the `key_buffer_size' variable to a large value helps the repair operation run faster. For a description of the output format, see *Note myisamchk-table-info::. * `--fast', `-F' Check only tables that haven't been closed properly. * `--force', `-f' Do a repair operation automatically if *Note `myisamchk': myisamchk. finds any errors in the table. The repair type is the same as that specified with the `--recover' or `-r' option. * `--information', `-i' Print informational statistics about the table that is checked. * `--medium-check', `-m' Do a check that is faster than an `--extend-check' operation. This finds only 99.99% of all errors, which should be good enough in most cases. * `--read-only', `-T' Do not mark the table as checked. This is useful if you use *Note `myisamchk': myisamchk. to check a table that is in use by some other application that does not use locking, such as *Note `mysqld': mysqld. when run with external locking disabled. * `--update-state', `-U' Store information in the `.MYI' file to indicate when the table was checked and whether the table crashed. This should be used to get full benefit of the `--check-only-changed' option, but you shouldn't use this option if the *Note `mysqld': mysqld. server is using the table and you are running it with external locking disabled.  File: manual.info, Node: myisamchk-repair-options, Next: myisamchk-other-options, Prev: myisamchk-check-options, Up: myisamchk 5.6.3.3 `myisamchk' Repair Options .................................. *Note `myisamchk': myisamchk. supports the following options for table repair operations (operations performed when an option such as `--recover' or `--safe-recover' is given): * `--backup', `-B' Make a backup of the `.MYD' file as `FILE_NAME-TIME.BAK' * `--character-sets-dir=PATH' The directory where character sets are installed. See *Note charset-configuration::. * `--correct-checksum' Correct the checksum information for the table. * `--data-file-length=LEN', `-D LEN' The maximum length of the data file (when re-creating data file when it is `full'). * `--extend-check', `-e' Do a repair that tries to recover every possible row from the data file. Normally, this also finds a lot of garbage rows. Do not use this option unless you are desperate. For a description of the output format, see *Note myisamchk-table-info::. * `--force', `-f' Overwrite old intermediate files (files with names like `TBL_NAME.TMD') instead of aborting. * `--keys-used=VAL', `-k VAL' For *Note `myisamchk': myisamchk, the option value is a bit-value that indicates which indexes to update. Each binary bit of the option value corresponds to a table index, where the first index is bit 0. An option value of 0 disables updates to all indexes, which can be used to get faster inserts. Deactivated indexes can be reactivated by using *Note `myisamchk -r': myisamchk. * `--no-symlinks', `-l' Do not follow symbolic links. Normally *Note `myisamchk': myisamchk. repairs the table that a symlink points to. This option does not exist as of MySQL 4.0 because versions from 4.0 on do not remove symlinks during repair operations. * `--max-record-length=LEN' Skip rows larger than the given length if *Note `myisamchk': myisamchk. cannot allocate memory to hold them. * `--parallel-recover', `-p' Use the same technique as `-r' and `-n', but create all the keys in parallel, using different threads. _This is beta-quality code. Use at your own risk!_ * `--quick', `-q' Achieve a faster repair by modifying only the index file, not the data file. You can specify this option twice to force *Note `myisamchk': myisamchk. to modify the original data file in case of duplicate keys. * `--recover', `-r' Do a repair that can fix almost any problem except unique keys that are not unique (which is an extremely unlikely error with `MyISAM' tables). If you want to recover a table, this is the option to try first. You should try `--safe-recover' only if *Note `myisamchk': myisamchk. reports that the table cannot be recovered using `--recover'. (In the unlikely case that `--recover' fails, the data file remains intact.) If you have lots of memory, you should increase the value of `sort_buffer_size'. * `--safe-recover', `-o' Do a repair using an old recovery method that reads through all rows in order and updates all index trees based on the rows found. This is an order of magnitude slower than `--recover', but can handle a couple of very unlikely cases that `--recover' cannot. This recovery method also uses much less disk space than `--recover'. Normally, you should repair first using `--recover', and then with `--safe-recover' only if `--recover' fails. If you have lots of memory, you should increase the value of `key_buffer_size'. * `--set-character-set=NAME' Change the character set used by the table indexes. This option was replaced by `--set-collation' in MySQL 5.0.3. * `--set-collation=NAME' Specify the collation to use for sorting table indexes. The character set name is implied by the first part of the collation name. * `--sort-recover', `-n' Force *Note `myisamchk': myisamchk. to use sorting to resolve the keys even if the temporary files would be very large. * `--tmpdir=PATH', `-t PATH' The path of the directory to be used for storing temporary files. If this is not set, *Note `myisamchk': myisamchk. uses the value of the `TMPDIR' environment variable. `--tmpdir' can be set to a list of directory paths that are used successively in round-robin fashion for creating temporary files. The separator character between directory names is the colon (``:'') on Unix and the semicolon (``;'') on Windows, NetWare, and OS/2. * `--unpack', `-u' Unpack a table that was packed with *Note `myisampack': myisampack.  File: manual.info, Node: myisamchk-other-options, Next: myisamchk-table-info, Prev: myisamchk-repair-options, Up: myisamchk 5.6.3.4 Other `myisamchk' Options ................................. *Note `myisamchk': myisamchk. supports the following options for actions other than table checks and repairs: * `--analyze', `-a' Analyze the distribution of key values. This improves join performance by enabling the join optimizer to better choose the order in which to join the tables and which indexes it should use. To obtain information about the key distribution, use a *Note `myisamchk --description --verbose TBL_NAME': myisamchk. command or the `SHOW INDEX FROM TBL_NAME' statement. * `--block-search=OFFSET', `-b OFFSET' Find the record that a block at the given offset belongs to. * `--description', `-d' Print some descriptive information about the table. Specifying the `--verbose' option once or twice produces additional information. See *Note myisamchk-table-info::. * `--set-auto-increment[=VALUE]', `-A[VALUE]' Force `AUTO_INCREMENT' numbering for new records to start at the given value (or higher, if there are existing records with `AUTO_INCREMENT' values this large). If VALUE is not specified, `AUTO_INCREMENT' numbers for new records begin with the largest value currently in the table, plus one. * `--sort-index', `-S' Sort the index tree blocks in high-low order. This optimizes seeks and makes table scans that use indexes faster. * `--sort-records=N', `-R N' Sort records according to a particular index. This makes your data much more localized and may speed up range-based *Note `SELECT': select. and `ORDER BY' operations that use this index. (The first time you use this option to sort a table, it may be very slow.) To determine a table's index numbers, use *Note `SHOW INDEX': show-index, which displays a table's indexes in the same order that *Note `myisamchk': myisamchk. sees them. Indexes are numbered beginning with 1. If keys are not packed (`PACK_KEYS=0'), they have the same length, so when *Note `myisamchk': myisamchk. sorts and moves records, it just overwrites record offsets in the index. If keys are packed (`PACK_KEYS=1'), *Note `myisamchk': myisamchk. must unpack key blocks first, then re-create indexes and pack the key blocks again. (In this case, re-creating indexes is faster than updating offsets for each index.)  File: manual.info, Node: myisamchk-table-info, Next: myisamchk-memory, Prev: myisamchk-other-options, Up: myisamchk 5.6.3.5 Obtaining Table Information with `myisamchk' .................................................... To obtain a description of a `MyISAM' table or statistics about it, use the commands shown here. The output from these commands is explained later in this section. * *Note `myisamchk -d TBL_NAME': myisamchk. Runs *Note `myisamchk': myisamchk. in `describe mode' to produce a description of your table. If you start the MySQL server with external locking disabled, *Note `myisamchk': myisamchk. may report an error for a table that is updated while it runs. However, because *Note `myisamchk': myisamchk. does not change the table in describe mode, there is no risk of destroying data. * *Note `myisamchk -dv TBL_NAME': myisamchk. Adding `-v' runs *Note `myisamchk': myisamchk. in verbose mode so that it produces more information about the table. Adding `-v' a second time produces even more information. * *Note `myisamchk -eis TBL_NAME': myisamchk. Shows only the most important information from a table. This operation is slow because it must read the entire table. * *Note `myisamchk -eiv TBL_NAME': myisamchk. This is like `-eis', but tells you what is being done. The TBL_NAME argument can be either the name of a `MyISAM' table or the name of its index file, as described in *Note myisamchk::. Multiple TBL_NAME arguments can be given. Suppose that a table named `person' has the following structure. (The `MAX_ROWS' table option is included so that in the example output from *Note `myisamchk': myisamchk. shown later, some values are smaller and fit the output format more easily.) CREATE TABLE person ( id INT NOT NULL AUTO_INCREMENT, last_name VARCHAR(20) NOT NULL, first_name VARCHAR(20) NOT NULL, birth DATE, death DATE, PRIMARY KEY (id), INDEX (last_name, first_name), INDEX (birth) ) MAX_ROWS = 1000000; Suppose also that the table has these data and index file sizes: -rw-rw---- 1 mysql mysql 9347072 Aug 19 11:47 person.MYD -rw-rw---- 1 mysql mysql 6066176 Aug 19 11:47 person.MYI Example of *Note `myisamchk -dvv': myisamchk. output: MyISAM file: person Record format: Packed Character set: latin1_swedish_ci (8) File-version: 1 Creation time: 2009-08-19 16:47:41 Recover time: 2009-08-19 16:47:56 Status: checked,analyzed,optimized keys Auto increment key: 1 Last value: 306688 Data records: 306688 Deleted blocks: 0 Datafile parts: 306688 Deleted data: 0 Datafile pointer (bytes): 4 Keyfile pointer (bytes): 3 Datafile length: 9347072 Keyfile length: 6066176 Max datafile length: 4294967294 Max keyfile length: 17179868159 Recordlength: 54 table description: Key Start Len Index Type Rec/key Root Blocksize 1 2 4 unique long 1 99328 1024 2 6 20 multip. varchar prefix 512 3563520 1024 27 20 varchar 512 3 48 3 multip. uint24 NULL 306688 6065152 1024 Field Start Length Nullpos Nullbit Type 1 1 1 2 2 4 no zeros 3 6 21 varchar 4 27 21 varchar 5 48 3 1 1 no zeros 6 51 3 1 2 no zeros Explanations for the types of information *Note `myisamchk': myisamchk. produces are given here. `Keyfile' refers to the index file. `Record' and `row' are synonymous, as are `field' and `column.' The initial part of the table description contains these values: * `MyISAM file' Name of the `MyISAM' (index) file. * `Record format' The format used to store table rows. The preceding examples use `Fixed length'. Other possible values are `Compressed' and `Packed'. (`Packed' corresponds to what `SHOW TABLE STATUS' reports as `Dynamic'.) * `Chararacter set' The table default character set. * `File-version' Version of `MyISAM' format. Currently always 1. * `Creation time' When the data file was created. * `Recover time' When the index/data file was last reconstructed. * `Status' Table status flags. Possible values are `crashed', `open', `changed', `analyzed', `optimized keys', and `sorted index pages'. * `Auto increment key', `Last value' The key number associated the table's `AUTO_INCREMENT' column, and the most recently generated value for this column. These fields do not appear if there is no such column. * `Data records' The number of rows in the table. * `Deleted blocks' How many deleted blocks still have reserved space. You can optimize your table to minimize this space. See *Note myisam-optimization::. * `Datafile parts' For dynamic-row format, this indicates how many data blocks there are. For an optimized table without fragmented rows, this is the same as `Data records'. * `Deleted data' How many bytes of unreclaimed deleted data there are. You can optimize your table to minimize this space. See *Note myisam-optimization::. * `Datafile pointer' The size of the data file pointer, in bytes. It is usually 2, 3, 4, or 5 bytes. Most tables manage with 2 bytes, but this cannot be controlled from MySQL yet. For fixed tables, this is a row address. For dynamic tables, this is a byte address. * `Keyfile pointer' The size of the index file pointer, in bytes. It is usually 1, 2, or 3 bytes. Most tables manage with 2 bytes, but this is calculated automatically by MySQL. It is always a block address. * `Max datafile length' How long the table data file can become, in bytes. * `Max keyfile length' How long the table index file can become, in bytes. * `Recordlength' How much space each row takes, in bytes. The `table description' part of the output includes a list of all keys in the table. For each key, *Note `myisamchk': myisamchk. displays some low-level information: * `Key' This key's number. This value is shown only for the first column of the key. If this value is missing, the line corresponds to the second or later column of a multiple-column key. For the table shown in the example, there are two `table description' lines for the second index. This indicates that it is a multiple-part index with two parts. * `Start' Where in the row this portion of the index starts. * `Len' How long this portion of the index is. For packed numbers, this should always be the full length of the column. For strings, it may be shorter than the full length of the indexed column, because you can index a prefix of a string column. The total length of a multiple-part key is the sum of the `Len' values for all key parts. * `Index' Whether a key value can exist multiple times in the index. Possible values are `unique' or `multip.' (multiple). * `Type' What data type this portion of the index has. This is a `MyISAM' data type with the possible values `packed', `stripped', or `empty'. * `Root' Address of the root index block. * `Blocksize' The size of each index block. By default this is 1024, but the value may be changed at compile time when MySQL is built from source. * `Rec/key' This is a statistical value used by the optimizer. It tells how many rows there are per value for this index. A unique index always has a value of 1. This may be updated after a table is loaded (or greatly changed) with *Note `myisamchk -a': myisamchk. If this is not updated at all, a default value of 30 is given. The last part of the output provides information about each column: * `Field' The column number. * `Start' The byte position of the column within table rows. * `Length' The length of the column in bytes. * `Nullpos', `Nullbit' For columns that can be `NULL', `MyISAM' stores `NULL' values as a flag in a byte. Depending on how many nullable columns there are, there can be one or more bytes used for this purpose. The `Nullpos' and `Nullbit' values, if nonempty, indicate which byte and bit contains that flag indicating whether the column is `NULL'. The position and number of bytes used to store `NULL' flags is shown in the line for field 1. This is why there are six `Field' lines for the `person' table even though it has only five columns. * `Type' The data type. The value may contain any of the following descriptors: * `constant' All rows have the same value. * `no endspace' Do not store endspace. * `no endspace, not_always' Do not store endspace and do not do endspace compression for all values. * `no endspace, no empty' Do not store endspace. Do not store empty values. * `table-lookup' The column was converted to an *Note `ENUM': enum. * `zerofill(N)' The most significant N bytes in the value are always 0 and are not stored. * `no zeros' Do not store zeros. * `always zero' Zero values are stored using one bit. * `Huff tree' The number of the Huffman tree associated with the column. * `Bits' The number of bits used in the Huffman tree. The `Huff tree' and `Bits' fields are displayed if the table has been compressed with *Note `myisampack': myisampack. See *Note myisampack::, for an example of this information. Example of *Note `myisamchk -eiv': myisamchk. output: Checking MyISAM file: person Data records: 306688 Deleted blocks: 0 - check file-size - check record delete-chain No recordlinks - check key delete-chain block_size 1024: - check index reference - check data record references index: 1 Key: 1: Keyblocks used: 98% Packed: 0% Max levels: 3 - check data record references index: 2 Key: 2: Keyblocks used: 99% Packed: 97% Max levels: 3 - check data record references index: 3 Key: 3: Keyblocks used: 98% Packed: -14% Max levels: 3 Total: Keyblocks used: 98% Packed: 89% - check records and index references *** LOTS OF ROW NUMBERS DELETED *** Records: 306688 M.recordlength: 25 Packed: 83% Recordspace used: 97% Empty space: 2% Blocks/Record: 1.00 Record blocks: 306688 Delete blocks: 0 Record data: 7934464 Deleted data: 0 Lost space: 256512 Linkdata: 1156096 User time 43.08, System time 1.68 Maximum resident set size 0, Integral resident set size 0 Non-physical pagefaults 0, Physical pagefaults 0, Swaps 0 Blocks in 0 out 7, Messages in 0 out 0, Signals 0 Voluntary context switches 0, Involuntary context switches 0 Maximum memory usage: 1046926 bytes (1023k) *Note `myisamchk -eiv': myisamchk. output includes the following information: * `Data records' The number of rows in the table. * `Deleted blocks' How many deleted blocks still have reserved space. You can optimize your table to minimize this space. See *Note myisam-optimization::. * `Key' The key number. * `Keyblocks used' What percentage of the keyblocks are used. When a table has just been reorganized with *Note `myisamchk': myisamchk, the values are very high (very near theoretical maximum). * `Packed' MySQL tries to pack key values that have a common suffix. This can only be used for indexes on *Note `CHAR': char. and *Note `VARCHAR': char. columns. For long indexed strings that have similar leftmost parts, this can significantly reduce the space used. In the preceding example, the second key is 40 bytes long and a 97% reduction in space is achieved. * `Max levels' How deep the B-tree for this key is. Large tables with long key values get high values. * `Records' How many rows are in the table. * `M.recordlength' The average row length. This is the exact row length for tables with fixed-length rows, because all rows have the same length. * `Packed' MySQL strips spaces from the end of strings. The `Packed' value indicates the percentage of savings achieved by doing this. * `Recordspace used' What percentage of the data file is used. * `Empty space' What percentage of the data file is unused. * `Blocks/Record' Average number of blocks per row (that is, how many links a fragmented row is composed of). This is always 1.0 for fixed-format tables. This value should stay as close to 1.0 as possible. If it gets too large, you can reorganize the table. See *Note myisam-optimization::. * `Recordblocks' How many blocks (links) are used. For fixed-format tables, this is the same as the number of rows. * `Deleteblocks' How many blocks (links) are deleted. * `Recorddata' How many bytes in the data file are used. * `Deleted data' How many bytes in the data file are deleted (unused). * `Lost space' If a row is updated to a shorter length, some space is lost. This is the sum of all such losses, in bytes. * `Linkdata' When the dynamic table format is used, row fragments are linked with pointers (4 to 7 bytes each). `Linkdata' is the sum of the amount of storage used by all such pointers.  File: manual.info, Node: myisamchk-memory, Prev: myisamchk-table-info, Up: myisamchk 5.6.3.6 `myisamchk' Memory Usage ................................ Memory allocation is important when you run *Note `myisamchk': myisamchk. *Note `myisamchk': myisamchk. uses no more memory than its memory-related variables are set to. If you are going to use *Note `myisamchk': myisamchk. on very large tables, you should first decide how much memory you want it to use. The default is to use only about 3MB to perform repairs. By using larger values, you can get *Note `myisamchk': myisamchk. to operate faster. For example, if you have more than 512MB RAM available, you could use options such as these (in addition to any other options you might specify): shell> myisamchk --sort_buffer_size=256M \ --key_buffer_size=512M \ --read_buffer_size=64M \ --write_buffer_size=64M ... Using `--sort_buffer_size=16M' is probably enough for most cases. Be aware that *Note `myisamchk': myisamchk. uses temporary files in `TMPDIR'. If `TMPDIR' points to a memory file system, out of memory errors can easily occur. If this happens, run *Note `myisamchk': myisamchk. with the `--tmpdir=PATH' option to specify a directory located on a file system that has more space. When performing repair operations, *Note `myisamchk': myisamchk. also needs a lot of disk space: * Twice the size of the data file (the original file and a copy). This space is not needed if you do a repair with `--quick'; in this case, only the index file is re-created. _This space must be available on the same file system as the original data file_, as the copy is created in the same directory as the original. * Space for the new index file that replaces the old one. The old index file is truncated at the start of the repair operation, so you usually ignore this space. This space must be available on the same file system as the original data file. * When using `--recover' or `--sort-recover' (but not when using `--safe-recover'), you need space on disk for sorting. This space is allocated in the temporary directory (specified by `TMPDIR' or `--tmpdir=PATH'). The following formula yields the amount of space required: (LARGEST_KEY + ROW_POINTER_LENGTH) * NUMBER_OF_ROWS * 2 You can check the length of the keys and the ROW_POINTER_LENGTH with *Note `myisamchk -dv TBL_NAME': myisamchk. (see *Note myisamchk-table-info::). The ROW_POINTER_LENGTH and NUMBER_OF_ROWS values are the `Datafile pointer' and `Data records' values in the table description. To determine the LARGEST_KEY value, check the `Key' lines in the table description. The `Len' column indicates the number of bytes for each key part. For a multiple-column index, the key size is the sum of the `Len' values for all key parts. If you have a problem with disk space during repair, you can try `--safe-recover' instead of `--recover'.  File: manual.info, Node: myisamlog, Next: myisampack, Prev: myisamchk, Up: programs-admin-utils 5.6.4 `myisamlog' -- Display MyISAM Log File Contents ----------------------------------------------------- *Note `myisamlog': myisamlog. processes the contents of a `MyISAM' log file. Invoke *Note `myisamlog': myisamlog. like this: shell> myisamlog [OPTIONS] [LOG_FILE [TBL_NAME] ...] shell> isamlog [OPTIONS] [LOG_FILE [TBL_NAME] ...] The default operation is update (`-u'). If a recovery is done (`-r'), all writes and possibly updates and deletes are done and errors are only counted. The default log file name is `myisam.log' for *Note `myisamlog': myisamlog. and `isam.log' for `isamlog' if no LOG_FILE argument is given. If tables are named on the command line, only those tables are updated. *Note `myisamlog': myisamlog. supports the following options: * `-?', `-I' Display a help message and exit. * `-c N' Execute only N commands. * `-f N' Specify the maximum number of open files. * `-i' Display extra information before exiting. * `-o OFFSET' Specify the starting offset. * `-p N' Remove N components from path. * `-r' Perform a recovery operation. * `-R RECORD_POS_FILE RECORD_POS' Specify record position file and record position. * `-u' Perform an update operation. * `-v' Verbose mode. Print more output about what the program does. This option can be given multiple times to produce more and more output. * `-w WRITE_FILE' Specify the write file. * `-V' Display version information.  File: manual.info, Node: myisampack, Next: mysqlaccess, Prev: myisamlog, Up: programs-admin-utils 5.6.5 `myisampack' -- Generate Compressed, Read-Only MyISAM Tables ------------------------------------------------------------------ The *Note `myisampack': myisampack. utility compresses `MyISAM' tables. *Note `myisampack': myisampack. works by compressing each column in the table separately. Usually, *Note `myisampack': myisampack. packs the data file 40% to 70%. When the table is used later, the server reads into memory the information needed to decompress columns. This results in much better performance when accessing individual rows, because you only have to uncompress exactly one row. MySQL uses `mmap()' when possible to perform memory mapping on compressed tables. If `mmap()' does not work, MySQL falls back to normal read/write file operations. Please note the following: * If the *Note `mysqld': mysqld. server was invoked with external locking disabled, it is not a good idea to invoke *Note `myisampack': myisampack. if the table might be updated by the server during the packing process. It is safest to compress tables with the server stopped. * After packing a table, it becomes read only. This is generally intended (such as when accessing packed tables on a CD). Invoke *Note `myisampack': myisampack. like this: shell> myisampack [OPTIONS] FILE_NAME ... Each file name argument should be the name of an index (`.MYI') file. If you are not in the database directory, you should specify the path name to the file. It is permissible to omit the `.MYI' extension. After you compress a table with *Note `myisampack': myisampack, you should use *Note `myisamchk -rq': myisamchk. to rebuild its indexes. *Note myisamchk::. *Note `myisampack': myisampack. supports the following options. It also reads option files and supports the options for processing them described at *Note option-file-options::. * `--help', `-?' Display a help message and exit. * `--backup', `-b' Make a backup of each table's data file using the name `TBL_NAME.OLD'. * `--character-sets-dir=PATH' The directory where character sets are installed. See *Note charset-configuration::. * `--debug[=DEBUG_OPTIONS]', `-# [DEBUG_OPTIONS]' Write a debugging log. A typical DEBUG_OPTIONS string is `'d:t:o,FILE_NAME''. The default is `'d:t:o''. * `--force', `-f' Produce a packed table even if it becomes larger than the original or if the intermediate file from an earlier invocation of *Note `myisampack': myisampack. exists. (*Note `myisampack': myisampack. creates an intermediate file named `TBL_NAME.TMD' in the database directory while it compresses the table. If you kill *Note `myisampack': myisampack, the `.TMD' file might not be deleted.) Normally, *Note `myisampack': myisampack. exits with an error if it finds that `TBL_NAME.TMD' exists. With `--force', *Note `myisampack': myisampack. packs the table anyway. * `--join=BIG_TBL_NAME', `-j BIG_TBL_NAME' Join all tables named on the command line into a single packed table BIG_TBL_NAME. All tables that are to be combined _must_ have identical structure (same column names and types, same indexes, and so forth). BIG_TBL_NAME must not exist prior to the join operation. All source tables named on the command line to be merged into BIG_TBL_NAME must exist. The source tables are read for the join operation but not modified. The join operation does not create a `.frm' file for BIG_TBL_NAME, so after the join operation finishes, copy the `.frm' file from one of the source tables and name it `BIG_TBL_NAME.frm'. * `--silent', `-s' Silent mode. Write output only when errors occur. * `--test', `-t' Do not actually pack the table, just test packing it. * `--tmpdir=PATH', `-T PATH' Use the named directory as the location where *Note `myisampack': myisampack. creates temporary files. * `--verbose', `-v' Verbose mode. Write information about the progress of the packing operation and its result. * `--version', `-V' Display version information and exit. * `--wait', `-w' Wait and retry if the table is in use. If the *Note `mysqld': mysqld. server was invoked with external locking disabled, it is not a good idea to invoke *Note `myisampack': myisampack. if the table might be updated by the server during the packing process. The following sequence of commands illustrates a typical table compression session: shell> ls -l station.* -rw-rw-r-- 1 monty my 994128 Apr 17 19:00 station.MYD -rw-rw-r-- 1 monty my 53248 Apr 17 19:00 station.MYI -rw-rw-r-- 1 monty my 5767 Apr 17 19:00 station.frm shell> myisamchk -dvv station MyISAM file: station Isam-version: 2 Creation time: 1996-03-13 10:08:58 Recover time: 1997-02-02 3:06:43 Data records: 1192 Deleted blocks: 0 Datafile parts: 1192 Deleted data: 0 Datafile pointer (bytes): 2 Keyfile pointer (bytes): 2 Max datafile length: 54657023 Max keyfile length: 33554431 Recordlength: 834 Record format: Fixed length table description: Key Start Len Index Type Root Blocksize Rec/key 1 2 4 unique unsigned long 1024 1024 1 2 32 30 multip. text 10240 1024 1 Field Start Length Type 1 1 1 2 2 4 3 6 4 4 10 1 5 11 20 6 31 1 7 32 30 8 62 35 9 97 35 10 132 35 11 167 4 12 171 16 13 187 35 14 222 4 15 226 16 16 242 20 17 262 20 18 282 20 19 302 30 20 332 4 21 336 4 22 340 1 23 341 8 24 349 8 25 357 8 26 365 2 27 367 2 28 369 4 29 373 4 30 377 1 31 378 2 32 380 8 33 388 4 34 392 4 35 396 4 36 400 4 37 404 1 38 405 4 39 409 4 40 413 4 41 417 4 42 421 4 43 425 4 44 429 20 45 449 30 46 479 1 47 480 1 48 481 79 49 560 79 50 639 79 51 718 79 52 797 8 53 805 1 54 806 1 55 807 20 56 827 4 57 831 4 shell> myisampack station.MYI Compressing station.MYI: (1192 records) - Calculating statistics normal: 20 empty-space: 16 empty-zero: 12 empty-fill: 11 pre-space: 0 end-space: 12 table-lookups: 5 zero: 7 Original trees: 57 After join: 17 - Compressing file 87.14% Remember to run myisamchk -rq on compressed tables shell> ls -l station.* -rw-rw-r-- 1 monty my 127874 Apr 17 19:00 station.MYD -rw-rw-r-- 1 monty my 55296 Apr 17 19:04 station.MYI -rw-rw-r-- 1 monty my 5767 Apr 17 19:00 station.frm shell> myisamchk -dvv station MyISAM file: station Isam-version: 2 Creation time: 1996-03-13 10:08:58 Recover time: 1997-04-17 19:04:26 Data records: 1192 Deleted blocks: 0 Datafile parts: 1192 Deleted data: 0 Datafile pointer (bytes): 3 Keyfile pointer (bytes): 1 Max datafile length: 16777215 Max keyfile length: 131071 Recordlength: 834 Record format: Compressed table description: Key Start Len Index Type Root Blocksize Rec/key 1 2 4 unique unsigned long 10240 1024 1 2 32 30 multip. text 54272 1024 1 Field Start Length Type Huff tree Bits 1 1 1 constant 1 0 2 2 4 zerofill(1) 2 9 3 6 4 no zeros, zerofill(1) 2 9 4 10 1 3 9 5 11 20 table-lookup 4 0 6 31 1 3 9 7 32 30 no endspace, not_always 5 9 8 62 35 no endspace, not_always, no empty 6 9 9 97 35 no empty 7 9 10 132 35 no endspace, not_always, no empty 6 9 11 167 4 zerofill(1) 2 9 12 171 16 no endspace, not_always, no empty 5 9 13 187 35 no endspace, not_always, no empty 6 9 14 222 4 zerofill(1) 2 9 15 226 16 no endspace, not_always, no empty 5 9 16 242 20 no endspace, not_always 8 9 17 262 20 no endspace, no empty 8 9 18 282 20 no endspace, no empty 5 9 19 302 30 no endspace, no empty 6 9 20 332 4 always zero 2 9 21 336 4 always zero 2 9 22 340 1 3 9 23 341 8 table-lookup 9 0 24 349 8 table-lookup 10 0 25 357 8 always zero 2 9 26 365 2 2 9 27 367 2 no zeros, zerofill(1) 2 9 28 369 4 no zeros, zerofill(1) 2 9 29 373 4 table-lookup 11 0 30 377 1 3 9 31 378 2 no zeros, zerofill(1) 2 9 32 380 8 no zeros 2 9 33 388 4 always zero 2 9 34 392 4 table-lookup 12 0 35 396 4 no zeros, zerofill(1) 13 9 36 400 4 no zeros, zerofill(1) 2 9 37 404 1 2 9 38 405 4 no zeros 2 9 39 409 4 always zero 2 9 40 413 4 no zeros 2 9 41 417 4 always zero 2 9 42 421 4 no zeros 2 9 43 425 4 always zero 2 9 44 429 20 no empty 3 9 45 449 30 no empty 3 9 46 479 1 14 4 47 480 1 14 4 48 481 79 no endspace, no empty 15 9 49 560 79 no empty 2 9 50 639 79 no empty 2 9 51 718 79 no endspace 16 9 52 797 8 no empty 2 9 53 805 1 17 1 54 806 1 3 9 55 807 20 no empty 3 9 56 827 4 no zeros, zerofill(2) 2 9 57 831 4 no zeros, zerofill(1) 2 9 *Note `myisampack': myisampack. displays the following kinds of information: * `normal' The number of columns for which no extra packing is used. * `empty-space' The number of columns containing values that are only spaces. These occupy one bit. * `empty-zero' The number of columns containing values that are only binary zeros. These occupy one bit. * `empty-fill' The number of integer columns that do not occupy the full byte range of their type. These are changed to a smaller type. For example, a *Note `BIGINT': numeric-types. column (eight bytes) can be stored as a *Note `TINYINT': numeric-types. column (one byte) if all its values are in the range from `-128' to `127'. * `pre-space' The number of decimal columns that are stored with leading spaces. In this case, each value contains a count for the number of leading spaces. * `end-space' The number of columns that have a lot of trailing spaces. In this case, each value contains a count for the number of trailing spaces. * `table-lookup' The column had only a small number of different values, which were converted to an *Note `ENUM': enum. before Huffman compression. * `zero' The number of columns for which all values are zero. * `Original trees' The initial number of Huffman trees. * `After join' The number of distinct Huffman trees left after joining trees to save some header space. After a table has been compressed, the `Field' lines displayed by *Note `myisamchk -dvv': myisamchk. include additional information about each column: * `Type' The data type. The value may contain any of the following descriptors: * `constant' All rows have the same value. * `no endspace' Do not store endspace. * `no endspace, not_always' Do not store endspace and do not do endspace compression for all values. * `no endspace, no empty' Do not store endspace. Do not store empty values. * `table-lookup' The column was converted to an *Note `ENUM': enum. * `zerofill(N)' The most significant N bytes in the value are always 0 and are not stored. * `no zeros' Do not store zeros. * `always zero' Zero values are stored using one bit. * `Huff tree' The number of the Huffman tree associated with the column. * `Bits' The number of bits used in the Huffman tree. After you run *Note `myisampack': myisampack, you must run *Note `myisamchk': myisamchk. to re-create any indexes. At this time, you can also sort the index blocks and create statistics needed for the MySQL optimizer to work more efficiently: shell> myisamchk -rq --sort-index --analyze TBL_NAME.MYI After you have installed the packed table into the MySQL database directory, you should execute *Note `mysqladmin flush-tables': mysqladmin. to force *Note `mysqld': mysqld. to start using the new table. To unpack a packed table, use the `--unpack' option to *Note `myisamchk': myisamchk.  File: manual.info, Node: mysqlaccess, Next: mysqlbinlog, Prev: myisampack, Up: programs-admin-utils 5.6.6 `mysqlaccess' -- Client for Checking Access Privileges ------------------------------------------------------------ *Note `mysqlaccess': mysqlaccess. is a diagnostic tool that Yves Carlier has provided for the MySQL distribution. It checks the access privileges for a host name, user name, and database combination. Note that *Note `mysqlaccess': mysqlaccess. checks access using only the `user', `db', and `host' tables. It does not check table, column, or routine privileges specified in the `tables_priv', `columns_priv', or `procs_priv' tables. Invoke *Note `mysqlaccess': mysqlaccess. like this: shell> mysqlaccess [HOST_NAME [USER_NAME [DB_NAME]]] [OPTIONS] *Note `mysqlaccess': mysqlaccess. supports the following options. *`mysqlaccess' Options* Format Option File Description IntroductionDeprecatedRemoved -brief brief Generate reports in single-line tabular format -commit commit Copy the new access privileges from the temporary tables to the original grant tables -copy copy Reload the temporary grant tables from original ones -db=db_name db Specify the database name -debug=# debug Specify the debug level -help Display help message and exit -host=host_namehost Connect to the MySQL server on the given host -howto howto Display some examples that show how to use mysqlaccess -old_server old_server Assume that the server is an old MySQL server (prior to MySQL 3.21) -password[=password]password The password to use when connecting to the server -plan plan Display suggestions and ideas for future releases -preview preview Show the privilege differences after making changes to the temporary grant tables -relnotes relnotes Display the release notes -rhost=host_namerhost Connect to the MySQL server on the given host -rollback rollback Undo the most recent changes to the temporary grant tables. -spassword[=password]spassword The password to use when connecting to the server as the superuser -superuser=user_namesuperuser Specify the user name for connecting as the superuser -table table Generate reports in table format -user=user_name,user The MySQL user name to use when connecting -version Display version information and exit * `--help', `-?' Display a help message and exit. * `--brief', `-b' Generate reports in single-line tabular format. * `--commit' Copy the new access privileges from the temporary tables to the original grant tables. The grant tables must be flushed for the new privileges to take effect. (For example, execute a *Note `mysqladmin reload': mysqladmin. command.) * `--copy' Reload the temporary grant tables from original ones. * `--db=DB_NAME', `-d DB_NAME' Specify the database name. * `--debug=N' Specify the debug level. N can be an integer from 0 to 3. * `--host=HOST_NAME', `-h HOST_NAME' The host name to use in the access privileges. * `--howto' Display some examples that show how to use *Note `mysqlaccess': mysqlaccess. * `--old_server' Assume that the server is an old MySQL server (before MySQL 3.21) that does not yet know how to handle full `WHERE' clauses. * `--password[=PASSWORD]', `-p[PASSWORD]' The password to use when connecting to the server. If you omit the PASSWORD value following the `--password' or `-p' option on the command line, *Note `mysqlaccess': mysqlaccess. prompts for one. Specifying a password on the command line should be considered insecure. See *Note password-security-user::. * `--plan' Display suggestions and ideas for future releases. * `--preview' Show the privilege differences after making changes to the temporary grant tables. * `--relnotes' Display the release notes. * `--rhost=HOST_NAME', `-H HOST_NAME' Connect to the MySQL server on the given host. * `--rollback' Undo the most recent changes to the temporary grant tables. * `--spassword[=PASSWORD]', `-P[PASSWORD]' The password to use when connecting to the server as the superuser. If you omit the PASSWORD value following the `--spassword' or `-p' option on the command line, *Note `mysqlaccess': mysqlaccess. prompts for one. Specifying a password on the command line should be considered insecure. See *Note password-security-user::. * `--superuser=USER_NAME', `-U USER_NAME' Specify the user name for connecting as the superuser. * `--table', `-t' Generate reports in table format. * `--user=USER_NAME', `-u USER_NAME' The user name to use in the access privileges. * `--version', `-v' Display version information and exit. If your MySQL distribution is installed in some nonstandard location, you must change the location where *Note `mysqlaccess': mysqlaccess. expects to find the *Note `mysql': mysql. client. Edit the `mysqlaccess' script at approximately line 18. Search for a line that looks like this: $MYSQL = '/usr/local/bin/mysql'; # path to mysql executable Change the path to reflect the location where *Note `mysql': mysql. actually is stored on your system. If you do not do this, a `Broken pipe' error will occur when you run *Note `mysqlaccess': mysqlaccess.  File: manual.info, Node: mysqlbinlog, Next: mysqldumpslow, Prev: mysqlaccess, Up: programs-admin-utils 5.6.7 `mysqlbinlog' -- Utility for Processing Binary Log Files -------------------------------------------------------------- * Menu: * mysqlbinlog-hexdump:: `mysqlbinlog' Hex Dump Format * mysqlbinlog-row-events:: `mysqlbinlog' Row Event Display The server's binary log consists of files containing `events' that describe modifications to database contents. The server writes these files in binary format. To display their contents in text format, use the *Note `mysqlbinlog': mysqlbinlog. utility. You can also use *Note `mysqlbinlog': mysqlbinlog. to display the contents of relay log files written by a slave server in a replication setup because relay logs have the same format as binary logs. The binary log and relay log are discussed further in *Note binary-log::, and *Note slave-logs::. Invoke *Note `mysqlbinlog': mysqlbinlog. like this: shell> mysqlbinlog [OPTIONS] LOG_FILE ... For example, to display the contents of the binary log file named `binlog.000003', use this command: shell> mysqlbinlog binlog.0000003 The output includes events contained in `binlog.000003'. For statement-based logging, event information includes the SQL statement, the ID of the server on which it was executed, the timestamp when the statement was executed, how much time it took, and so forth. For row-based logging, the event indicates a row change rather than an SQL statement. See *Note replication-formats::, for information about logging modes. Events are preceded by header comments that provide additional information. For example: # at 141 #100309 9:28:36 server id 123 end_log_pos 245 Query thread_id=3350 exec_time=11 error_code=0 In the first line, the number following `at' indicates the starting position of the event in the binary log file. The second line starts with a date and time indicating when the statement started on the server where the event originated. For replication, this timestamp is propagated to slave servers. `server id' is the `server_id' value of the server where the event originated. `end_log_pos' indicates where the next event starts (that is, it is the end position of the current event + 1). `thread_id' indicates which thread executed the event. `exec_time' is the time spent executing the event, on a master server. On a slave, it is the difference of the end execution time on the slave minus the beginning execution time on the master. The difference serves as an indicator of how much replication lags behind the master. `error_code' indicates the result from executing the event. Zero means that no error occurred. The output from *Note `mysqlbinlog': mysqlbinlog. can be re-executed (for example, by using it as input to *Note `mysql': mysql.) to redo the statements in the log. This is useful for recovery operations after a server crash. For other usage examples, see the discussion later in this section and in *Note point-in-time-recovery::. Normally, you use *Note `mysqlbinlog': mysqlbinlog. to read binary log files directly and apply them to the local MySQL server. It is also possible to read binary logs from a remote server by using the `--read-from-remote-server' option. To read remote binary logs, the connection parameter options can be given to indicate how to connect to the server. These options are `--host', `--password', `--port', `--protocol', `--socket', and `--user'; they are ignored except when you also use the `--read-from-remote-server' option. *Note `mysqlbinlog': mysqlbinlog. supports the following options, which can be specified on the command line or in the `[mysqlbinlog]' and `[client]' option file groups. *Note `mysqlbinlog': mysqlbinlog. also supports the options for processing option files described at *Note option-file-options::. *`mysqlbinlog' Options* Format Option File Description IntroductionDeprecatedRemoved -base64-output[=value]base64-outputPrint binary log entries 5.1.5 using base-64 encoding -bind-address=ip_addressbind-addressUse the specified network 5.1.22-ndb-6.3.4 interface to connect to the MySQL Server -character-sets-dir=pathcharacter-sets-dirThe directory where character sets are installed -database=db_namedatabase List entries for just this database -debug[=debug_options]debug Write a debugging log -debug-checkdebug-check Print debugging information 5.1.21 when the program exits -debug-info debug-info Print debugging information, 5.1.21 memory and CPU statistics when the program exits -disable-log-bindisable-log-binDisable binary logging -force-read force-read If mysqlbinlog reads a binary log event that it does not recognize, it prints a warning -help Display help message and exit -hexdump hexdump Display a hex dump of the 5.1.2 log in comments -host=host_namehost Connect to the MySQL server on the given host -local-load=pathlocal-load Prepare local temporary files for LOAD DATA INFILE in the specified directory -offset=# offset Skip the first N entries in the log -password[=password]password The password to use when connecting to the server -port=port_numport The TCP/IP port number to use for the connection -position=# position Deprecated. Use -start-position -protocol=typeprotocol The connection protocol to use -read-from-remote-serverread-from-remote-serverRead the binary log from a MySQL server rather than reading a local log file -result-file=nameresult-file Direct output to the given file -server-id=idserver-id Extract only those events 5.1.4 created by the server having the given server ID -server-id-bits=#server-id-bitsTell mysqlbinlog how to 5.1.47-ndb-7.1.6 interpret the server IDs in the binary log when the binary log was written by a mysqld having its server-id-bits set to less than the maximum. Supported only by the MySQL Cluster version of mysqlbinlog. -set-charset=charset_nameset-charset Add a SET NAMES charset_name 5.1.12 statement to the output -short-form short-form Display only the statements contained in the log -socket=pathsocket For connections to localhost -start-datetime=datetimestart-datetimeStart reading the binary log at the first event having a timestamp equal to or later than the datetime argument -start-position=#start-positionStart reading the binary log at the first event having a position equal to or greater than the argument -stop-datetime=datetimestop-datetimeStop reading the binary log at the first event having a timestamp equal to or greater than the datetime argument -stop-position=#stop-positionStop reading the binary log at the first event having a position equal to or greater than the argument -to-last-logto-last-log Do not stop at the end of the requested binary log from a MySQL server, but rather continue printing until the end of the last binary log -user=user_name,user The MySQL user name to use when connecting to the server -verbose Reconstruct row events as 5.1.28 SQL statements -version Display version information and exit * `--help', `-?' Display a help message and exit. * `--base64-output[=VALUE]' This option determines when events should be displayed encoded as base-64 strings using *Note `BINLOG': binlog. statements. The option has these permissible values (not case sensitive): * `AUTO' ("automatic") or `UNSPEC' ("unspecified") displays *Note `BINLOG': binlog. statements automatically when necessary (that is, for format description events and row events). If no `--base64-output' option is given, the effect is the same as `--base64-output=AUTO'. *Note*: Automatic *Note `BINLOG': binlog. display is the only safe behavior if you intend to use the output of *Note `mysqlbinlog': mysqlbinlog. to re-execute binary log file contents. The other option values are intended only for debugging or testing purposes because they may produce output that does not include all events in executable form. * `ALWAYS' displays *Note `BINLOG': binlog. statements whenever possible. If the `--base64-output' option is given without a value, the effect is the same as `--base64-output=ALWAYS'. * `NEVER' causes *Note `BINLOG': binlog. statements not to be displayed. *Note `mysqlbinlog': mysqlbinlog. exits with an error if a row event is found that must be displayed using *Note `BINLOG': binlog. * `DECODE-ROWS' specifies to *Note `mysqlbinlog': mysqlbinlog. that you intend for row events to be decoded and displayed as commented SQL statements by also specifying the `--verbose' option. Like `NEVER', `DECODE-ROWS' suppresses display of *Note `BINLOG': binlog. statements, but unlike `NEVER', it does not exit with an error if a row event is found. The `--base64-output' option was introduced in MySQL 5.1.5, to be given as `--base64-output' or `--skip-base64-output' (with the sense of `AUTO' or `NEVER'). The option values described in the preceding list may be used as of MySQL 5.1.24, with the exception of `UNSPEC' and `DECODE-ROWS', which are available as of MySQL 5.1.28. For examples that show the effect of `--base64-output' and `--verbose' on row event output, see *Note mysqlbinlog-row-events::. * `--bind-address=IP_ADDRESS' On a computer having multiple network interfaces, this option can be used to select which interface is employed when connecting to the MySQL server. This option is supported only in the version of *Note `mysqlbinlog': mysqlbinlog. that is supplied with MySQL Cluster, beginning with MySQL Cluster NDB 6.3.4. It is not available in standard MySQL 5.1 releases. * `--character-sets-dir=PATH' The directory where character sets are installed. See *Note charset-configuration::. * `--database=DB_NAME', `-d DB_NAME' This option causes *Note `mysqlbinlog': mysqlbinlog. to output entries from the binary log (local log only) that occur while DB_NAME is been selected as the default database by *Note `USE': use. The `--database' option for *Note `mysqlbinlog': mysqlbinlog. is similar to the `--binlog-do-db' option for *Note `mysqld': mysqld, but can be used to specify only one database. If `--database' is given multiple times, only the last instance is used. The effects of this option depend on whether the statement-based or row-based logging format is in use, in the same way that the effects of `--binlog-do-db' depend on whether statement-based or row-based logging is in use. Statement-based logging The `--database' option works as follows: * While DB_NAME is the default database, statements are output whether they modify tables in DB_NAME or a different database. * Unless DB_NAME is selected as the default database, statements are not output, even if they modify tables in DB_NAME. * There is an exception for *Note `CREATE DATABASE': create-database, *Note `ALTER DATABASE': alter-database, and *Note `DROP DATABASE': drop-database. The database being _created, altered, or dropped_ is considered to be the default database when determining whether to output the statement. Suppose that the binary log was created by executing these statements using statement-based-logging: INSERT INTO test.t1 (i) VALUES(100); INSERT INTO db2.t2 (j) VALUES(200); USE test; INSERT INTO test.t1 (i) VALUES(101); INSERT INTO t1 (i) VALUES(102); INSERT INTO db2.t2 (j) VALUES(201); USE db2; INSERT INTO test.t1 (i) VALUES(103); INSERT INTO db2.t2 (j) VALUES(202); INSERT INTO t2 (j) VALUES(203); *Note `mysqlbinlog --database=test': mysqlbinlog. does not output the first two *Note `INSERT': insert. statements because there is no default database. It outputs the three *Note `INSERT': insert. statements following *Note `USE test': use, but not the three *Note `INSERT': insert. statements following *Note `USE db2': use. *Note `mysqlbinlog --database=db2': mysqlbinlog. does not output the first two *Note `INSERT': insert. statements because there is no default database. It does not output the three *Note `INSERT': insert. statements following *Note `USE test': use, but does output the three *Note `INSERT': insert. statements following *Note `USE db2': use. Row-based logging *Note `mysqlbinlog': mysqlbinlog. outputs only entries that change tables belonging to DB_NAME. The default database has no effect on this. Suppose that the binary log just described was created using row-based logging rather than statement-based logging. *Note `mysqlbinlog --database=test': mysqlbinlog. outputs only those entries that modify `t1' in the test database, regardless of whether *Note `USE': use. was issued or what the default database is. If a server is running with `binlog_format' set to `MIXED' and you want it to be possible to use *Note `mysqlbinlog': mysqlbinlog. with the `--database' option, you must ensure that tables that are modified are in the database selected by *Note `USE': use. (In particular, no cross-database updates should be used.) *Note*: This option did not work correctly for *Note `mysqlbinlog': mysqlbinlog. with row-based logging prior to MySQL 5.1.37. (Bug#42941) * `--debug[=DEBUG_OPTIONS]', `-# [DEBUG_OPTIONS]' Write a debugging log. A typical DEBUG_OPTIONS string is `'d:t:o,FILE_NAME''. The default is `'d:t:o,/tmp/mysqlbinlog.trace''. * `--debug-check' Print some debugging information when the program exits. This option was added in MySQL 5.1.21. * `--debug-info' Print debugging information and memory and CPU usage statistics when the program exits. This option was added in MySQL 5.1.21. * `--disable-log-bin', `-D' Disable binary logging. This is useful for avoiding an endless loop if you use the `--to-last-log' option and are sending the output to the same MySQL server. This option also is useful when restoring after a crash to avoid duplication of the statements you have logged. This option requires that you have the `SUPER' privilege. It causes *Note `mysqlbinlog': mysqlbinlog. to include a `SET sql_log_bin = 0' statement in its output to disable binary logging of the remaining output. The *Note `SET': set-option. statement is ineffective unless you have the `SUPER' privilege. * `--force-read', `-f' With this option, if *Note `mysqlbinlog': mysqlbinlog. reads a binary log event that it does not recognize, it prints a warning, ignores the event, and continues. Without this option, *Note `mysqlbinlog': mysqlbinlog. stops if it reads such an event. * `--hexdump', `-H' Display a hex dump of the log in comments, as described in *Note mysqlbinlog-hexdump::. The hex output can be helpful for replication debugging. This option was added in MySQL 5.1.2. * `--host=HOST_NAME', `-h HOST_NAME' Get the binary log from the MySQL server on the given host. * `--local-load=PATH', `-l PATH' Prepare local temporary files for *Note `LOAD DATA INFILE': load-data. in the specified directory. *Important*: These temporary files are not automatically removed by *Note `mysqlbinlog': mysqlbinlog. or any other MySQL program. * `--offset=N', `-o N' Skip the first N entries in the log. * `--password[=PASSWORD]', `-p[PASSWORD]' The password to use when connecting to the server. If you use the short option form (`-p'), you _cannot_ have a space between the option and the password. If you omit the PASSWORD value following the `--password' or `-p' option on the command line, *Note `mysqlbinlog': mysqlbinlog. prompts for one. Specifying a password on the command line should be considered insecure. See *Note password-security-user::. You can use an option file to avoid giving the password on the command line. * `--port=PORT_NUM', `-P PORT_NUM' The TCP/IP port number to use for connecting to a remote server. * `--position=N' Deprecated. Use `--start-position' instead. `--position' is removed in MySQL 5.5. * `--protocol={TCP|SOCKET|PIPE|MEMORY}' The connection protocol to use for connecting to the server. It is useful when the other connection parameters normally would cause a protocol to be used other than the one you want. For details on the permissible values, see *Note connecting::. * `--read-from-remote-server', `-R' Read the binary log from a MySQL server rather than reading a local log file. Any connection parameter options are ignored unless this option is given as well. These options are `--host', `--password', `--port', `--protocol', `--socket', and `--user'. This option requires that the remote server be running. It works only for binary log files on the remote server, not relay log files. * `--result-file=NAME', `-r NAME' Direct output to the given file. * `--server-id=ID' Display only those events created by the server having the given server ID. This option is available as of MySQL 5.1.4. * `--server-id-bits=N' Use only the first N bits of the `server_id' to identify the server. If the binary log was written by a *Note `mysqld': mysqld. with server-id-bits set to less than 32 and user data stored in the most significant bit, running *Note `mysqlbinlog': mysqlbinlog. with `--server-id-bits' set to 32 enables this data to be seen. This option was added in MySQL Cluster NDB 7.0.17 and MySQL Cluster NDB 7.1.6, and is supported only by the versions of *Note `mysqlbinlog': mysqlbinlog. supplied with these and later releases of MySQL Cluster. * `--set-charset=CHARSET_NAME' Add a `SET NAMES CHARSET_NAME' statement to the output to specify the character set to be used for processing log files. This option was added in MySQL 5.1.12. * `--short-form', `-s' Display only the statements contained in the log, without any extra information or row-based events. This is for testing only, and should not be used in production systems. * `--socket=PATH', `-S PATH' For connections to `localhost', the Unix socket file to use, or, on Windows, the name of the named pipe to use. * `--start-datetime=DATETIME' Start reading the binary log at the first event having a timestamp equal to or later than the DATETIME argument. The DATETIME value is relative to the local time zone on the machine where you run *Note `mysqlbinlog': mysqlbinlog. The value should be in a format accepted for the *Note `DATETIME': datetime. or *Note `TIMESTAMP': datetime. data types. For example: shell> mysqlbinlog --start-datetime="2005-12-25 11:25:56" binlog.000003 This option is useful for point-in-time recovery. See *Note backup-strategy-example::. * `--start-position=N', `-j N' Start reading the binary log at the first event having a position equal to or greater than N. This option applies to the first log file named on the command line. This option is useful for point-in-time recovery. See *Note backup-strategy-example::. * `--stop-datetime=DATETIME' Stop reading the binary log at the first event having a timestamp equal to or later than the DATETIME argument. This option is useful for point-in-time recovery. See the description of the `--start-datetime' option for information about the DATETIME value. This option is useful for point-in-time recovery. See *Note backup-strategy-example::. * `--stop-position=N' Stop reading the binary log at the first event having a position equal to or greater than N. This option applies to the last log file named on the command line. This option is useful for point-in-time recovery. See *Note backup-strategy-example::. * `--to-last-log', `-t' Do not stop at the end of the requested binary log from a MySQL server, but rather continue printing until the end of the last binary log. If you send the output to the same MySQL server, this may lead to an endless loop. This option requires `--read-from-remote-server'. * `--user=USER_NAME', `-u USER_NAME' The MySQL user name to use when connecting to a remote server. * `--verbose', `-v' Reconstruct row events and display them as commented SQL statements. If this option is given twice, the output includes comments to indicate column data types and some metadata. This option was added in MySQL 5.1.28. For examples that show the effect of `--base64-output' and `--verbose' on row event output, see *Note mysqlbinlog-row-events::. * `--version', `-V' Display version information and exit. You can also set the following variable by using `--VAR_NAME=VALUE' syntax: * `open_files_limit' Specify the number of open file descriptors to reserve. You can pipe the output of *Note `mysqlbinlog': mysqlbinlog. into the *Note `mysql': mysql. client to execute the events contained in the binary log. This technique is used to recover from a crash when you have an old backup (see *Note point-in-time-recovery::). For example: shell> mysqlbinlog binlog.000001 | mysql -u root -p Or: shell> mysqlbinlog binlog.[0-9]* | mysql -u root -p You can also redirect the output of *Note `mysqlbinlog': mysqlbinlog. to a text file instead, if you need to modify the statement log first (for example, to remove statements that you do not want to execute for some reason). After editing the file, execute the statements that it contains by using it as input to the *Note `mysql': mysql. program: shell> mysqlbinlog binlog.000001 > tmpfile shell> ... EDIT TMPFILE ... shell> mysql -u root -p < tmpfile When *Note `mysqlbinlog': mysqlbinlog. is invoked with the `--start-position' option, it displays only those events with an offset in the binary log greater than or equal to a given position (the given position must match the start of one event). It also has options to stop and start when it sees an event with a given date and time. This enables you to perform point-in-time recovery using the `--stop-datetime' option (to be able to say, for example, `roll forward my databases to how they were today at 10:30 a.m.'). If you have more than one binary log to execute on the MySQL server, the safe method is to process them all using a single connection to the server. Here is an example that demonstrates what may be _unsafe_: shell> mysqlbinlog binlog.000001 | mysql -u root -p # DANGER!! shell> mysqlbinlog binlog.000002 | mysql -u root -p # DANGER!! Processing binary logs this way using multiple connections to the server causes problems if the first log file contains a *Note `CREATE TEMPORARY TABLE': create-table. statement and the second log contains a statement that uses the temporary table. When the first *Note `mysql': mysql. process terminates, the server drops the temporary table. When the second *Note `mysql': mysql. process attempts to use the table, the server reports `unknown table.' To avoid problems like this, use a _single_ *Note `mysql': mysql. process to execute the contents of all binary logs that you want to process. Here is one way to do so: shell> mysqlbinlog binlog.000001 binlog.000002 | mysql -u root -p Another approach is to write all the logs to a single file and then process the file: shell> mysqlbinlog binlog.000001 > /tmp/statements.sql shell> mysqlbinlog binlog.000002 >> /tmp/statements.sql shell> mysql -u root -p -e "source /tmp/statements.sql" *Note `mysqlbinlog': mysqlbinlog. can produce output that reproduces a *Note `LOAD DATA INFILE': load-data. operation without the original data file. *Note `mysqlbinlog': mysqlbinlog. copies the data to a temporary file and writes a *Note `LOAD DATA LOCAL INFILE': load-data. statement that refers to the file. The default location of the directory where these files are written is system-specific. To specify a directory explicitly, use the `--local-load' option. Because *Note `mysqlbinlog': mysqlbinlog. converts *Note `LOAD DATA INFILE': load-data. statements to *Note `LOAD DATA LOCAL INFILE': load-data. statements (that is, it adds `LOCAL'), both the client and the server that you use to process the statements must be configured with the `LOCAL' capability enabled. See *Note load-data-local::. *Warning*: The temporary files created for *Note `LOAD DATA LOCAL': load-data. statements are _not_ automatically deleted because they are needed until you actually execute those statements. You should delete the temporary files yourself after you no longer need the statement log. The files can be found in the temporary file directory and have names like ORIGINAL_FILE_NAME-#-#.  File: manual.info, Node: mysqlbinlog-hexdump, Next: mysqlbinlog-row-events, Prev: mysqlbinlog, Up: mysqlbinlog 5.6.7.1 `mysqlbinlog' Hex Dump Format ..................................... The `--hexdump' option causes *Note `mysqlbinlog': mysqlbinlog. to produce a hex dump of the binary log contents: shell> mysqlbinlog --hexdump master-bin.000001 The hex output consists of comment lines beginning with `#', so the output might look like this for the preceding command: /*!40019 SET @@session.max_insert_delayed_threads=0*/; /*!50003 SET @OLD_COMPLETION_TYPE=@@COMPLETION_TYPE,COMPLETION_TYPE=0*/; # at 4 #051024 17:24:13 server id 1 end_log_pos 98 # Position Timestamp Type Master ID Size Master Pos Flags # 00000004 9d fc 5c 43 0f 01 00 00 00 5e 00 00 00 62 00 00 00 00 00 # 00000017 04 00 35 2e 30 2e 31 35 2d 64 65 62 75 67 2d 6c |..5.0.15.debug.l| # 00000027 6f 67 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |og..............| # 00000037 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| # 00000047 00 00 00 00 9d fc 5c 43 13 38 0d 00 08 00 12 00 |.......C.8......| # 00000057 04 04 04 04 12 00 00 4b 00 04 1a |.......K...| # Start: binlog v 4, server v 5.0.15-debug-log created 051024 17:24:13 # at startup ROLLBACK; Hex dump output currently contains the elements in the following list. This format is subject to change. (For more information about binary log format, see `http://forge.mysql.com/wiki/MySQL_Internals_Binary_Log'.) * `Position': The byte position within the log file. * `Timestamp': The event timestamp. In the example shown, `'9d fc 5c 43'' is the representation of `'051024 17:24:13'' in hexadecimal. * `Type': The event type code. In the example shown, `'0f'' indicates a `FORMAT_DESCRIPTION_EVENT'. The following table lists the possible type codes. Type Name Meaning `00' `UNKNOWN_EVENT' This event should never be present in the log. `01' `START_EVENT_V3' This indicates the start of a log file written by MySQL 4 or earlier. `02' `QUERY_EVENT' The most common type of events. These contain statements executed on the master. `03' `STOP_EVENT' Indicates that master has stopped. `04' `ROTATE_EVENT' Written when the master switches to a new log file. `05' `INTVAR_EVENT' Used for `AUTO_INCREMENT' values or when the `LAST_INSERT_ID()' function is used in the statement. `06' `LOAD_EVENT' Used for *Note `LOAD DATA INFILE': load-data. in MySQL 3.23. `07' `SLAVE_EVENT' Reserved for future use. `08' `CREATE_FILE_EVENT' Used for *Note `LOAD DATA INFILE': load-data. statements. This indicates the start of execution of such a statement. A temporary file is created on the slave. Used in MySQL 4 only. `09' `APPEND_BLOCK_EVENT' Contains data for use in a *Note `LOAD DATA INFILE': load-data. statement. The data is stored in the temporary file on the slave. `0a' `EXEC_LOAD_EVENT' Used for *Note `LOAD DATA INFILE': load-data. statements. The contents of the temporary file is stored in the table on the slave. Used in MySQL 4 only. `0b' `DELETE_FILE_EVENT' Rollback of a *Note `LOAD DATA INFILE': load-data. statement. The temporary file should be deleted on the slave. `0c' `NEW_LOAD_EVENT' Used for *Note `LOAD DATA INFILE': load-data. in MySQL 4 and earlier. `0d' `RAND_EVENT' Used to send information about random values if the `RAND()' function is used in the statement. `0e' `USER_VAR_EVENT' Used to replicate user variables. `0f' `FORMAT_DESCRIPTION_EVENT'This indicates the start of a log file written by MySQL 5 or later. `10' `XID_EVENT' Event indicating commit of an XA transaction. `11' `BEGIN_LOAD_QUERY_EVENT'Used for *Note `LOAD DATA INFILE': load-data. statements in MySQL 5 and later. `12' `EXECUTE_LOAD_QUERY_EVENT'Used for *Note `LOAD DATA INFILE': load-data. statements in MySQL 5 and later. `13' `TABLE_MAP_EVENT' Information about a table definition. Used in MySQL 5.1.5 and later. `14' `PRE_GA_WRITE_ROWS_EVENT'Row data for a single table that should be created. Used in MySQL 5.1.5 to 5.1.17. `15' `PRE_GA_UPDATE_ROWS_EVENT'Row data for a single table that needs to be updated. Used in MySQL 5.1.5 to 5.1.17. `16' `PRE_GA_DELETE_ROWS_EVENT'Row data for a single table that should be deleted. Used in MySQL 5.1.5 to 5.1.17. `17' `WRITE_ROWS_EVENT' Row data for a single table that should be created. Used in MySQL 5.1.18 and later. `18' `UPDATE_ROWS_EVENT' Row data for a single table that needs to be updated. Used in MySQL 5.1.18 and later. `19' `DELETE_ROWS_EVENT' Row data for a single table that should be deleted. Used in MySQL 5.1.18 and later. `1a' `INCIDENT_EVENT' Something out of the ordinary happened. Added in MySQL 5.1.18. * `Master ID': The server ID of the master that created the event. * `Size': The size in bytes of the event. * `Master Pos': The position of the next event in the original master log file. * `Flags': 16 flags. Currently, the following flags are used. The others are reserved for future use. Flag Name Meaning `01' `LOG_EVENT_BINLOG_IN_USE_F'Log file correctly closed. (Used only in `FORMAT_DESCRIPTION_EVENT'.) If this flag is set (if the flags are, for example, `'01 00'') in a `FORMAT_DESCRIPTION_EVENT', the log file has not been properly closed. Most probably this is because of a master crash (for example, due to power failure). `02' Reserved for future use. `04' `LOG_EVENT_THREAD_SPECIFIC_F'Set if the event is dependent on the connection it was executed in (for example, `'04 00''), for example, if the event uses temporary tables. `08' `LOG_EVENT_SUPPRESS_USE_F'Set in some circumstances when the event is not dependent on the default database.  File: manual.info, Node: mysqlbinlog-row-events, Prev: mysqlbinlog-hexdump, Up: mysqlbinlog 5.6.7.2 `mysqlbinlog' Row Event Display ....................................... The following examples illustrate how *Note `mysqlbinlog': mysqlbinlog. displays row events that specify data modifications. These correspond to events with the `WRITE_ROWS_EVENT', `UPDATE_ROWS_EVENT', and `DELETE_ROWS_EVENT' type codes. The `--base64-output=DECODE-ROWS' and `--verbose' options may be used to affect row event output. These options are available as of MySQL 5.1.28. Suppose that the server is using row-based binary logging and that you execute the following sequence of statements: CREATE TABLE t ( id INT NOT NULL, name VARCHAR(20) NOT NULL, date DATE NULL ) ENGINE = InnoDB; START TRANSACTION; INSERT INTO t VALUES(1, 'apple', NULL); UPDATE t SET name = 'pear', date = '2009-01-01' WHERE id = 1; DELETE FROM t WHERE id = 1; COMMIT; By default, *Note `mysqlbinlog': mysqlbinlog. displays row events encoded as base-64 strings using *Note `BINLOG': binlog. statements. Omitting extraneous lines, the output for the row events produced by the preceding statement sequence looks like this: shell> mysqlbinlog LOG_FILE ... # at 218 #080828 15:03:08 server id 1 end_log_pos 258 Write_rows: table id 17 flags: STMT_END_F BINLOG ' fAS3SBMBAAAALAAAANoAAAAAABEAAAAAAAAABHRlc3QAAXQAAwMPCgIUAAQ= fAS3SBcBAAAAKAAAAAIBAAAQABEAAAAAAAEAA//8AQAAAAVhcHBsZQ== '/*!*/; ... # at 302 #080828 15:03:08 server id 1 end_log_pos 356 Update_rows: table id 17 flags: STMT_END_F BINLOG ' fAS3SBMBAAAALAAAAC4BAAAAABEAAAAAAAAABHRlc3QAAXQAAwMPCgIUAAQ= fAS3SBgBAAAANgAAAGQBAAAQABEAAAAAAAEAA////AEAAAAFYXBwbGX4AQAAAARwZWFyIbIP '/*!*/; ... # at 400 #080828 15:03:08 server id 1 end_log_pos 442 Delete_rows: table id 17 flags: STMT_END_F BINLOG ' fAS3SBMBAAAALAAAAJABAAAAABEAAAAAAAAABHRlc3QAAXQAAwMPCgIUAAQ= fAS3SBkBAAAAKgAAALoBAAAQABEAAAAAAAEAA//4AQAAAARwZWFyIbIP '/*!*/; To see the row events as comments in the form of `pseudo-SQL' statements, run *Note `mysqlbinlog': mysqlbinlog. with the `--verbose' or `-v' option. The output will contain lines beginning with `###': shell> mysqlbinlog -v LOG_FILE ... # at 218 #080828 15:03:08 server id 1 end_log_pos 258 Write_rows: table id 17 flags: STMT_END_F BINLOG ' fAS3SBMBAAAALAAAANoAAAAAABEAAAAAAAAABHRlc3QAAXQAAwMPCgIUAAQ= fAS3SBcBAAAAKAAAAAIBAAAQABEAAAAAAAEAA//8AQAAAAVhcHBsZQ== '/*!*/; ### INSERT INTO test.t ### SET ### @1=1 ### @2='apple' ### @3=NULL ... # at 302 #080828 15:03:08 server id 1 end_log_pos 356 Update_rows: table id 17 flags: STMT_END_F BINLOG ' fAS3SBMBAAAALAAAAC4BAAAAABEAAAAAAAAABHRlc3QAAXQAAwMPCgIUAAQ= fAS3SBgBAAAANgAAAGQBAAAQABEAAAAAAAEAA////AEAAAAFYXBwbGX4AQAAAARwZWFyIbIP '/*!*/; ### UPDATE test.t ### WHERE ### @1=1 ### @2='apple' ### @3=NULL ### SET ### @1=1 ### @2='pear' ### @3='2009:01:01' ... # at 400 #080828 15:03:08 server id 1 end_log_pos 442 Delete_rows: table id 17 flags: STMT_END_F BINLOG ' fAS3SBMBAAAALAAAAJABAAAAABEAAAAAAAAABHRlc3QAAXQAAwMPCgIUAAQ= fAS3SBkBAAAAKgAAALoBAAAQABEAAAAAAAEAA//4AQAAAARwZWFyIbIP '/*!*/; ### DELETE FROM test.t ### WHERE ### @1=1 ### @2='pear' ### @3='2009:01:01' Specify `--verbose' or `-v' twice to also display data types and some metadata for each column. The output will contain an additional comment following each column change: shell> mysqlbinlog -vv LOG_FILE ... # at 218 #080828 15:03:08 server id 1 end_log_pos 258 Write_rows: table id 17 flags: STMT_END_F BINLOG ' fAS3SBMBAAAALAAAANoAAAAAABEAAAAAAAAABHRlc3QAAXQAAwMPCgIUAAQ= fAS3SBcBAAAAKAAAAAIBAAAQABEAAAAAAAEAA//8AQAAAAVhcHBsZQ== '/*!*/; ### INSERT INTO test.t ### SET ### @1=1 /* INT meta=0 nullable=0 is_null=0 */ ### @2='apple' /* VARSTRING(20) meta=20 nullable=0 is_null=0 */ ### @3=NULL /* VARSTRING(20) meta=0 nullable=1 is_null=1 */ ... # at 302 #080828 15:03:08 server id 1 end_log_pos 356 Update_rows: table id 17 flags: STMT_END_F BINLOG ' fAS3SBMBAAAALAAAAC4BAAAAABEAAAAAAAAABHRlc3QAAXQAAwMPCgIUAAQ= fAS3SBgBAAAANgAAAGQBAAAQABEAAAAAAAEAA////AEAAAAFYXBwbGX4AQAAAARwZWFyIbIP '/*!*/; ### UPDATE test.t ### WHERE ### @1=1 /* INT meta=0 nullable=0 is_null=0 */ ### @2='apple' /* VARSTRING(20) meta=20 nullable=0 is_null=0 */ ### @3=NULL /* VARSTRING(20) meta=0 nullable=1 is_null=1 */ ### SET ### @1=1 /* INT meta=0 nullable=0 is_null=0 */ ### @2='pear' /* VARSTRING(20) meta=20 nullable=0 is_null=0 */ ### @3='2009:01:01' /* DATE meta=0 nullable=1 is_null=0 */ ... # at 400 #080828 15:03:08 server id 1 end_log_pos 442 Delete_rows: table id 17 flags: STMT_END_F BINLOG ' fAS3SBMBAAAALAAAAJABAAAAABEAAAAAAAAABHRlc3QAAXQAAwMPCgIUAAQ= fAS3SBkBAAAAKgAAALoBAAAQABEAAAAAAAEAA//4AQAAAARwZWFyIbIP '/*!*/; ### DELETE FROM test.t ### WHERE ### @1=1 /* INT meta=0 nullable=0 is_null=0 */ ### @2='pear' /* VARSTRING(20) meta=20 nullable=0 is_null=0 */ ### @3='2009:01:01' /* DATE meta=0 nullable=1 is_null=0 */ You can tell *Note `mysqlbinlog': mysqlbinlog. to suppress the *Note `BINLOG': binlog. statements for row events by using the `--base64-output=DECODE-ROWS' option. This is similar to `--base64-output=NEVER' but does not exit with an error if a row event is found. The combination of `--base64-output=DECODE-ROWS' and `--verbose' provides a convenient way to see row events only as SQL statements: shell> mysqlbinlog -v --base64-output=DECODE-ROWS LOG_FILE ... # at 218 #080828 15:03:08 server id 1 end_log_pos 258 Write_rows: table id 17 flags: STMT_END_F ### INSERT INTO test.t ### SET ### @1=1 ### @2='apple' ### @3=NULL ... # at 302 #080828 15:03:08 server id 1 end_log_pos 356 Update_rows: table id 17 flags: STMT_END_F ### UPDATE test.t ### WHERE ### @1=1 ### @2='apple' ### @3=NULL ### SET ### @1=1 ### @2='pear' ### @3='2009:01:01' ... # at 400 #080828 15:03:08 server id 1 end_log_pos 442 Delete_rows: table id 17 flags: STMT_END_F ### DELETE FROM test.t ### WHERE ### @1=1 ### @2='pear' ### @3='2009:01:01' *Note*: You should not suppress *Note `BINLOG': binlog. statements if you intend to re-execute *Note `mysqlbinlog': mysqlbinlog. output. The SQL statements produced by `--verbose' for row events are much more readable than the corresponding *Note `BINLOG': binlog. statements. However, they do not correspond exactly to the original SQL statements that generated the events. The following limitations apply: * The original column names are lost and replaced by `@N', where N is a column number. * Character set information is not available in the binary log, which affects string column display: * There is no distinction made between corresponding binary and nonbinary string types (*Note `BINARY': binary-varbinary. and *Note `CHAR': char, *Note `VARBINARY': binary-varbinary. and *Note `VARCHAR': char, *Note `BLOB': blob. and *Note `TEXT': blob.). The output uses a data type of `STRING' for fixed-length strings and `VARSTRING' for variable-length strings. * For multi-byte character sets, the maximum number of bytes per character is not present in the binary log, so the length for string types is displayed in bytes rather than in characters. For example, `STRING(4)' will be used as the data type for values from either of these column types: CHAR(4) CHARACTER SET latin1 CHAR(2) CHARACTER SET ucs2 * Due to the storage format for events of type `UPDATE_ROWS_EVENT', *Note `UPDATE': update. statements are displayed with the `WHERE' clause preceding the `SET' clause. Proper interpretation of row events requires the information from the format description event at the beginning of the binary log. Because *Note `mysqlbinlog': mysqlbinlog. does not know in advance whether the rest of the log contains row events, by default it displays the format description event using a *Note `BINLOG': binlog. statement in the initial part of the output. If the binary log is known not to contain any events requiring a *Note `BINLOG': binlog. statement (that is, no row events), the `--base64-output=NEVER' option can be used to prevent this header from being written.  File: manual.info, Node: mysqldumpslow, Next: mysqlhotcopy, Prev: mysqlbinlog, Up: programs-admin-utils 5.6.8 `mysqldumpslow' -- Summarize Slow Query Log Files ------------------------------------------------------- The MySQL slow query log contains information about queries that take a long time to execute (see *Note slow-query-log::). *Note `mysqldumpslow': mysqldumpslow. parses MySQL slow query log files and prints a summary of their contents. Normally, *Note `mysqldumpslow': mysqldumpslow. groups queries that are similar except for the particular values of number and string data values. It `abstracts' these values to `N' and `'S'' when displaying summary output. The `-a' and `-n' options can be used to modify value abstracting behavior. Invoke *Note `mysqldumpslow': mysqldumpslow. like this: shell> mysqldumpslow [OPTIONS] [LOG_FILE ...] *Note `mysqldumpslow': mysqldumpslow. supports the following options. *`mysqldumpslow' Options* Format Option File Description IntroductionDeprecatedRemoved -a Do not abstract all numbers to N and strings to S -n num Abstract numbers with at least the specified digits -debug debug Write debugging information -g pattern Only consider statements that match the pattern -help Display help message and exit -h name Host name of the server in the log file name -i name Name of the server instance -l Do not subtract lock time from total time -r Reverse the sort order -s value How to sort output -t num Display only first num queries -verbose verbose Verbose mode * `--help' Display a help message and exit. * `-a' Do not abstract all numbers to `N' and strings to `'S''. * `--debug', `-d' Run in debug mode. * `-g PATTERN' Consider only queries that match the (`grep'-style) pattern. * `-h HOST_NAME' Host name of MySQL server for `*-slow.log' file name. The value can contain a wildcard. The default is `*' (match all). * `-i NAME' Name of server instance (if using *Note `mysql.server': mysql-server. startup script). * `-l' Do not subtract lock time from total time. * `-n N' Abstract numbers with at least N digits within names. * `-r' Reverse the sort order. * `-s SORT_TYPE' How to sort the output. The value of SORT_TYPE should be chosen from the following list: * `t', `at': Sort by query time or average query time * `l', `al': Sort by lock time or average lock time * `r', `ar': Sort by rows sent or average rows sent * `c': Sort by count By default, *Note `mysqldumpslow': mysqldumpslow. sorts by average query time (equivalent to `-s at'). * `-t N' Display only the first N queries in the output. * `--verbose', `-v' Verbose mode. Print more information about what the program does. Example of usage: shell> mysqldumpslow Reading mysql slow query log from /usr/local/mysql/data/mysqld51-apple-slow.log Count: 1 Time=4.32s (4s) Lock=0.00s (0s) Rows=0.0 (0), root[root]@localhost insert into t2 select * from t1 Count: 3 Time=2.53s (7s) Lock=0.00s (0s) Rows=0.0 (0), root[root]@localhost insert into t2 select * from t1 limit N Count: 3 Time=2.13s (6s) Lock=0.00s (0s) Rows=0.0 (0), root[root]@localhost insert into t1 select * from t1  File: manual.info, Node: mysqlhotcopy, Next: instance-manager, Prev: mysqldumpslow, Up: programs-admin-utils 5.6.9 `mysqlhotcopy' -- A Database Backup Program ------------------------------------------------- *Note `mysqlhotcopy': mysqlhotcopy. is a Perl script that was originally written and contributed by Tim Bunce. It uses *Note `FLUSH TABLES': flush, *Note `LOCK TABLES': lock-tables, and `cp' or `scp' to make a database backup. It is a fast way to make a backup of the database or single tables, but it can be run only on the same machine where the database directories are located. *Note `mysqlhotcopy': mysqlhotcopy. works only for backing up `MyISAM' and `ARCHIVE' tables. It runs on Unix and NetWare. To use *Note `mysqlhotcopy': mysqlhotcopy, you must have read access to the files for the tables that you are backing up, the `SELECT' privilege for those tables, the `RELOAD' privilege (to be able to execute *Note `FLUSH TABLES': flush.), and the `LOCK TABLES' privilege (to be able to lock the tables). shell> mysqlhotcopy DB_NAME [/PATH/TO/NEW_DIRECTORY] shell> mysqlhotcopy DB_NAME_1 ... DB_NAME_N /PATH/TO/NEW_DIRECTORY Back up tables in the given database that match a regular expression: shell> mysqlhotcopy DB_NAME./REGEX/ The regular expression for the table name can be negated by prefixing it with a tilde (``~''): shell> mysqlhotcopy DB_NAME./~REGEX/ *Note `mysqlhotcopy': mysqlhotcopy. supports the following options, which can be specified on the command line or in the `[mysqlhotcopy]' and `[client]' option file groups. *`mysqlhotcopy' Options* Format Option File Description IntroductionDeprecatedRemoved -addtodest addtodest Do not rename target directory (if it exists); merely add files to it -allowold allowold Do not abort if a target exists; rename it by adding an _old suffix -checkpoint=db_name.tbl_namecheckpoint Insert checkpoint entries -chroot=pathchroot Base directory of the chroot jail in which mysqld operates -debug debug Write a debugging log -dryrun dryrun Report actions without performing them -flushlog flushlog Flush logs after all tables are locked -help Display help message and exit -host=host_namehost Connect to the MySQL server on the given host -keepold keepold Do not delete previous (renamed) target when done -noindices noindices Do not include full index files in the backup -password[=password]password The password to use when connecting to the server -port=port_numport The TCP/IP port number to use for the connection -quiet quiet Be silent except for errors -regexp regexp Copy all databases with names that match the given regular expression -resetmasterresetmaster Reset the binary log after locking all the tables -resetslave resetslave Reset the master.info file after locking all the tables -socket=pathsocket For connections to localhost -tmpdir=pathtmpdir The temporary directory -user=user_name,user The MySQL user name to use when connecting to the server * `--help', `-?' Display a help message and exit. * `--addtodest' Do not rename target directory (if it exists); merely add files to it. * `--allowold' Do not abort if a target exists; rename it by adding an `_old' suffix. * `--checkpoint=DB_NAME.TBL_NAME' Insert checkpoint entries into the specified database DB_NAME and table TBL_NAME. * `--chroot=PATH' Base directory of the `chroot' jail in which *Note `mysqld': mysqld. operates. The PATH value should match that of the `--chroot' option given to *Note `mysqld': mysqld. * `--debug' Enable debug output. * `--dryrun', `-n' Report actions without performing them. * `--flushlog' Flush logs after all tables are locked. * `--host=HOST_NAME', `-h HOST_NAME' The host name of the local host to use for making a TCP/IP connection to the local server. By default, the connection is made to `localhost' using a Unix socket file. * `--keepold' Do not delete previous (renamed) target when done. * `--method=COMMAND' The method for copying files (`cp' or `scp'). The default is `cp'. * `--noindices' Do not include full index files for *Note `MyISAM': myisam-storage-engine. tables in the backup. This makes the backup smaller and faster. The indexes for reloaded tables can be reconstructed later with *Note `myisamchk -rq': myisamchk. * `--password=PASSWORD', `-pPASSWORD' The password to use when connecting to the server. The password value is not optional for this option, unlike for other MySQL programs. Specifying a password on the command line should be considered insecure. See *Note password-security-user::. You can use an option file to avoid giving the password on the command line. * `--port=PORT_NUM', `-P PORT_NUM' The TCP/IP port number to use when connecting to the local server. * `--quiet', `-q' Be silent except for errors. * `--record_log_pos=DB_NAME.TBL_NAME' Record master and slave status in the specified database DB_NAME and table TBL_NAME. * `--regexp=EXPR' Copy all databases with names that match the given regular expression. * `--resetmaster' Reset the binary log after locking all the tables. * `--resetslave' Reset the `master.info' file after locking all the tables. * `--socket=PATH', `-S PATH' The Unix socket file to use for connections to `localhost'. * `--suffix=STR' The suffix to use for names of copied databases. * `--tmpdir=PATH' The temporary directory. The default is `/tmp'. * `--user=USER_NAME', `-u USER_NAME' The MySQL user name to use when connecting to the server. Use `perldoc' for additional *Note `mysqlhotcopy': mysqlhotcopy. documentation, including information about the structure of the tables needed for the `--checkpoint' and `--record_log_pos' options: shell> perldoc mysqlhotcopy  File: manual.info, Node: instance-manager, Next: mysql-convert-table-format, Prev: mysqlhotcopy, Up: programs-admin-utils 5.6.10 `mysqlmanager' -- The MySQL Instance Manager --------------------------------------------------- * Menu: * instance-manager-command-options:: MySQL Instance Manager Command Options * instance-manager-configuration-files:: MySQL Instance Manager Configuration Files * instance-manager-startup-process:: Starting the MySQL Server with MySQL Instance Manager * instance-manager-security-passwords:: Instance Manager User and Password Management * instance-manager-security-monitoring:: MySQL Server Instance Status Monitoring * instance-manager-security:: Connecting to MySQL Instance Manager * instance-manager-commands:: MySQL Instance Manager Commands *Important*: MySQL Instance Manager has been deprecated and is removed in MySQL 5.5. `mysqlmanager' is the MySQL Instance Manager (IM). This program monitors and manages MySQL Database Server instances. MySQL Instance Manager is available for Unix-like operating systems, as well as Windows. It runs as a daemon that listens on a TCP/IP port. On Unix, it also listens on a Unix socket file. MySQL Instance Manager can be used in place of the *Note `mysqld_safe': mysqld-safe. script to start and stop one or more instances of MySQL Server. Because Instance Manager can manage multiple server instances, it can also be used in place of the *Note `mysqld_multi': mysqld-multi. script. Instance Manager offers these capabilities: * Instance Manager can start and stop instances, and report on the status of instances. * Server instances can be treated as guarded or unguarded: * When Instance Manager starts, it starts each guarded instance. If the instance crashes, Instance Manager detects this and restarts it. When Instance Manager stops, it stops the instance. * A nonguarded instance is not started when Instance Manager starts or monitored by it. If the instance crashes after being started, Instance Manager does not restart it. When Instance Manager exits, it does not stop the instance if it is running. Instances are guarded by default. An instance can be designated as nonguarded by including the `nonguarded' option in the configuration file. * Instance Manager provides an interactive interface for configuring instances, so that the need to edit the configuration file manually is reduced or eliminated. * Instance Manager provides remote instance management. That is, it runs on the host where you want to control MySQL Server instances, but you can connect to it from a remote host to perform instance-management operations. The following sections describe MySQL Instance Manager operation in more detail.  File: manual.info, Node: instance-manager-command-options, Next: instance-manager-configuration-files, Prev: instance-manager, Up: instance-manager 5.6.10.1 MySQL Instance Manager Command Options ............................................... *Important*: MySQL Instance Manager has been deprecated and is removed in MySQL 5.5. The MySQL Instance Manager supports a number of command options. For a brief listing, invoke `mysqlmanager' with the `--help' option. Options may be given on the command line or in the Instance Manager configuration file. On Windows, the standard configuration file is `my.ini' in the directory where Instance Manager is installed. On Unix, the standard file is `/etc/my.cnf'. To specify a different configuration file, start Instance Manager with the `--defaults-file' option. `mysqlmanager' supports the following options. The options for managing entries in the password file are described further in *Note instance-manager-security-passwords::. * `--help', `-?' Display a help message and exit. * `--add-user' Add a new user (specified with the `--username' option) to the password file. This option was added in MySQL 5.1.12. * `--angel-pid-file=FILE_NAME' The file in which the angel process records its process ID when `mysqlmanager' runs in daemon mode (that is, when the `--run-as-service' option is given). The default file name is `mysqlmanager.angel.pid'. If the `--angel-pid-file' option is not given, the default angel PID file has the same name as the PID file except that any PID file extension is replaced with an extension of `.angel.pid'. (For example, `mysqlmanager.pid' becomes `mysqlmanager.angel.pid'.) This option was added in MySQL 5.1.11. * `--bind-address=IP' The IP address to bind to. * `--check-password-file' Check the validity and consistency of the password file. This option was added in MySQL 5.1.12. * `--clean-password-file' Drop all users from the password file. This option was added in MySQL 5.1.12. * `--debug=DEBUG_OPTIONS', `-# DEBUG_OPTIONS' Write a debugging log. A typical DEBUG_OPTIONS string is `'d:t:o,FILE_NAME''. This option was added in MySQL 5.1.10. * `--default-mysqld-path=PATH' The path name of the MySQL Server binary. This path name is used for all server instance sections in the configuration file for which no `mysqld-path' option is present. The default value of this option is the compiled-in path name, which depends on how the MySQL distribution was configured. Example: `--default-mysqld-path=/usr/sbin/mysqld' * `--defaults-file=FILE_NAME' Read Instance Manager and MySQL Server settings from the given file. All configuration changes made by the Instance Manager will be written to this file. This must be the first option on the command line if it is used, and the file must exist. If this option is not given, Instance Manager uses its standard configuration file. On Windows, the standard file is `my.ini' in the directory where Instance Manager is installed. On Unix, the standard file is `/etc/my.cnf'. * `--drop-user' Drop a user (specified with the `--username' option) from the password file. This option was added in MySQL 5.1.12. * `--edit-user' Change an entry for an existing user (specified with the `--username' option) in the password file. This option was added in MySQL 5.1.12. * `--install' On Windows, install Instance Manager as a Windows service. The service name is `MySQL Manager'. * `--list-users' List the users in the password file. This option was added in MySQL 5.1.12. * `--log=FILE_NAME' The path to the Instance Manager log file. This option has no effect unless the `--run-as-service' option is also given. If the file name specified for the option is a relative name, the log file is created under the directory from which Instance Manager is started. To ensure that the file is created in a specific directory, specify it as a full path name. If `--run-as-service' is given without `--log', the log file is `mysqlmanager.log' in the data directory. If `--run-as-service' is not given, log messages go to the standard output. To capture log output, you can redirect Instance Manager output to a file: mysqlmanager > im.log * `--monitoring-interval=SECONDS' The interval in seconds for monitoring server instances. The default value is 20 seconds. Instance Manager tries to connect to each monitored (guarded) instance using the nonexisting `MySQL_Instance_Manager' user account to check whether it is available/not hanging. If the result of the connection attempt indicates that the instance is unavailable, Instance Manager performs several attempts to restart the instance. Normally, the `MySQL_Instance_Manager' account does not exist, so the connection attempts by Instance Manager cause the monitored instance to produce messages in its general query log similar to the following: Access denied for user 'MySQL_Instance_M'@'localhost' » (using password: YES) The `nonguarded' option in the appropriate server instance section disables monitoring for a particular instance. If the instance dies after being started, Instance Manager will not restart it. Instance Manager tries to connect to a nonguarded instance only when you request the instance's status (for example, with the `SHOW INSTANCES' status. See *Note instance-manager-security-monitoring::, for more information. * `--mysqld-safe-compatible' Run in a *Note `mysqld_safe': mysqld-safe.-compatible manner. For details, see *Note instance-manager-startup-process::. This option was added in MySQL 5.1.12. * `--password=PASSWORD', `-p PASSWORD' Specify the password for an entry to be added to or modified in the password file. Unlike the `--password'/`-P' option for most MySQL programs, the password value is required, not optional. See also *Note instance-manager-security-passwords::. This option was added in MySQL 5.1.12. * `--password-file=FILE_NAME' The name of the file where the Instance Manager looks for users and passwords. On Windows, the default is `mysqlmanager.passwd' in the directory where Instance Manager is installed. On Unix, the default file is `/etc/mysqlmanager.passwd'. See also *Note instance-manager-security-passwords::. * `--pid-file=FILE_NAME' The process ID file to use. On Windows, the default file is `mysqlmanager.pid' in the directory where Instance Manager is installed. On Unix, the default is `mysqlmanager.pid' in the data directory. * `--port=PORT_NUM' The port number to use when listening for TCP/IP connections from clients. The default port number (assigned by IANA) is 2273. * `--print-defaults' Print the current defaults and exit. This must be the first option on the command line if it is used. * `--print-password-line' Prepare an entry for the password file, print it to the standard output, and exit. You can redirect the output from Instance Manager to a file to save the entry in the file. Prior to MySQL 5.1.12, this option was named `--passwd'. * `--remove' On Windows, removes Instance Manager as a Windows service. This assumes that Instance Manager has been run with `--install' previously. * `--run-as-service' On Unix, daemonize and start an angel process. The angel process monitors Instance Manager and restarts it if it crashes. (The angel process itself is simple and unlikely to crash.) * `--socket=PATH' On Unix, the socket file to use for incoming connections. The default file is named `/tmp/mysqlmanager.sock'. This option has no meaning on Windows. * `--standalone' This option is used on Windows to run Instance Manager in standalone mode. You should specify it when you start Instance Manager from the command line. * `--user=USER_NAME' On Unix, the user name of the system account to use for starting and running `mysqlmanager'. This option generates a warning and has no effect unless you start `mysqlmanager' as `root' (so that it can change its effective user ID), or as the named user. It is recommended that you configure `mysqlmanager' to run using the same account used to run the *Note `mysqld': mysqld. server. (`User' in this context refers to a system login account, not a MySQL user listed in the grant tables.) * `--username=USER_NAME', `-u USER_NAME' Specify the user name for an entry to be added to or modified in the password file. This option was added in MySQL 5.1.12. * `--version', `-V' Display version information and exit. * `--wait-timeout=N' The number of seconds to wait for activity on an incoming connection before closing it. The default is 28800 seconds (8 hours). This option was added in MySQL 5.1.7. Before that, the timeout is 30 seconds and cannot be changed.  File: manual.info, Node: instance-manager-configuration-files, Next: instance-manager-startup-process, Prev: instance-manager-command-options, Up: instance-manager 5.6.10.2 MySQL Instance Manager Configuration Files ................................................... *Important*: MySQL Instance Manager has been deprecated and is removed in MySQL 5.5. Instance Manager uses its standard configuration file unless it is started with a `--defaults-file' option that specifies a different file. On Windows, the standard file is `my.ini' in the directory where Instance Manager is installed. On Unix, the standard file is `/etc/my.cnf'. Instance Manager reads options for itself from the `[manager]' section of the configuration file, and options for server instances from `[mysqld]' or `[mysqldN]' sections. The `[manager]' section contains any of the options listed in *Note instance-manager-command-options::, except for those specified as having to be given as the first option on the command line. Here is a sample `[manager]' section: # MySQL Instance Manager options section [manager] default-mysqld-path = /usr/local/mysql/libexec/mysqld socket=/tmp/manager.sock pid-file=/tmp/manager.pid password-file = /home/cps/.mysqlmanager.passwd monitoring-interval = 2 port = 1999 bind-address = 192.168.1.5 Each `[mysqld]' or `[mysqldN]' instance section specifies options given by Instance Manager to a server instance at startup. These are mainly common MySQL Server options (see *Note server-options::). In addition, a `[mysqldN]' section can contain the options in the following list, which are specific to Instance Manager. These options are interpreted by Instance Manager itself; it does not pass them to the server when it attempts to start that server. *Warning*: The Instance Manager-specific options must not be used in a `[mysqld]' section. If a server is started without using Instance Manager, it will not recognize these options and will fail to start properly. * `mysqld-path = PATH' The path name of the *Note `mysqld': mysqld. server binary to use for the server instance. * `nonguarded' This option disables Instance Manager monitoring functionality for the server instance. By default, an instance is guarded: At Instance Manager start time, it starts the instance. It also monitors the instance status and attempts to restart it if it fails. At Instance Manager exit time, it stops the instance. None of these things happen for nonguarded instances. * `shutdown-delay = SECONDS' The number of seconds Instance Manager should wait for the server instance to shut down. The default value is 35 seconds. After the delay expires, Instance Manager assumes that the instance is hanging and attempts to terminate it. If you use `InnoDB' with large tables, you should increase this value. Here are some sample instance sections: [mysqld1] mysqld-path=/usr/local/mysql/libexec/mysqld socket=/tmp/mysql.sock port=3307 server_id=1 skip-stack-trace core-file log-bin log-error log=mylog log-slow-queries [mysqld2] nonguarded port=3308 server_id=2 mysqld-path= /home/cps/mysql/trees/mysql-5.1/sql/mysqld socket = /tmp/mysql.sock5 pid-file = /tmp/hostname.pid5 datadir= /home/cps/mysql_data/data_dir1 language=/home/cps/mysql/trees/mysql-5.1/sql/share/english log-bin log=/tmp/fordel.log  File: manual.info, Node: instance-manager-startup-process, Next: instance-manager-security-passwords, Prev: instance-manager-configuration-files, Up: instance-manager 5.6.10.3 Starting the MySQL Server with MySQL Instance Manager .............................................................. *Important*: MySQL Instance Manager has been deprecated and is removed in MySQL 5.5. This section discusses how Instance Manager starts server instances when it starts. However, before you start Instance Manager, you should set up a password file for it. Otherwise, you will not be able to connect to Instance Manager to control it after it starts. For details about creating Instance Manager accounts, see *Note instance-manager-security-passwords::. On Unix, the *Note `mysqld': mysqld. MySQL database server normally is started with the *Note `mysql.server': mysql-server. script, which usually resides in the `/etc/init.d/' folder. That script invokes the *Note `mysqld_safe': mysqld-safe. script by default. However, you can use Instance Manager instead if you modify the `/etc/my.cnf' configuration file by adding `use-manager' to the `[mysql.server]' section: [mysql.server] use-manager Before MySQL 5.1.12, Instance Manager always tries to start at least one server instance: When it starts, it reads its configuration file if it exists to find server instance sections and prepare a list of instances. Instance sections have names of the form `[mysqld]' or `[mysqldN]', where N is an unsigned integer (for example, `[mysqld1]', `[mysqld2]', and so forth). After preparing the list of instances, Instance Manager starts the guarded instances in the list. If there are no instances, Instance Manager creates an instance named `mysqld' and attempts to start it with default (compiled-in) configuration values. This means that the Instance Manager cannot find the *Note `mysqld': mysqld. program if it is not installed in the default location. (*Note installation-layouts::, describes default locations for components of MySQL distributions.) If you have installed the MySQL server in a nonstandard location, you should create the Instance Manager configuration file. The startup behavior just described is similar to that of *Note `mysqld_safe': mysqld-safe, which always attempts to start a server. However, it lacks the flexibility required for some operations because it is not possible to run Instance Manager in such a way that it refrains from starting any server instances. For example, you cannot invoke Instance Manager for the purpose of configuring an instance without also starting it (a task that a MySQL installer application might want to perform). Consequently, MySQL 5.1.12 introduces the following changes: * A new option, `--mysqld-safe-compatible', may be used to cause Instance Manager to run with startup behavior similar to that used before MySQL 5.1.12: If Instance Manager finds a `[mysqld]' instance section in the configuration file, it will start it. If Instance Manager finds no `[mysqld]' section, it creates one using default configuration values, writes a `[mysqld]' section to the configuration file if it is accessible, and starts the `mysqld' instance. Instance Manager also starts any other guarded instances listed in the configuration file. * Without `--mysqld-safe-compatible', Instance Manager reads its configuration file if it exists and starts instances for any guarded instance sections that it finds. If there are none, it starts no instances. Instance Manager also stops all guarded server instances when it shuts down. The permissible options for `[mysqldN]' server instance sections are described in *Note instance-manager-configuration-files::. In these sections, you can use a special `mysqld-path=PATH-TO-MYSQLD-BINARY' option that is recognized only by Instance Manager. Use this option to let Instance Manager know where the *Note `mysqld': mysqld. binary resides. If there are multiple instances, it may also be necessary to set other options such as `datadir' and `port', to ensure that each instance has a different data directory and TCP/IP port number. *Note multiple-servers::, discusses the configuration values that must differ for each instance when you run multiple instance on the same machine. *Warning*: The `[mysqld]' instance section, if it exists, must not contain any Instance Manager-specific options. The typical Unix startup/shutdown cycle for a MySQL server with the MySQL Instance Manager enabled is as follows: 1. The `/etc/init.d/mysql' script starts MySQL Instance Manager. 2. Instance Manager starts the guarded server instances and monitors them. 3. If a server instance fails, Instance Manager restarts it. 4. If Instance Manager is shut down (for example, with the `/etc/init.d/mysql stop' command), it shuts down all server instances.  File: manual.info, Node: instance-manager-security-passwords, Next: instance-manager-security-monitoring, Prev: instance-manager-startup-process, Up: instance-manager 5.6.10.4 Instance Manager User and Password Management ...................................................... *Important*: MySQL Instance Manager has been deprecated and is removed in MySQL 5.5. The Instance Manager stores its user information in a password file. On Windows, the default is `mysqlmanager.passwd' in the directory where Instance Manager is installed. On Unix, the default file is `/etc/mysqlmanager.passwd'. To specify a different location for the password file, use the `--password-file' option. If the password file does not exist or contains no password entries, you cannot connect to the Instance Manager. *Note*: Any Instance Manager process that is running to monitor server instances does not notice changes to the password file. You must stop it and restart it after making password entry changes. Entries in the password file have the following format, where the two fields are the account user name and encrypted password, separated by a colon: petr:*35110DC9B4D8140F5DE667E28C72DD2597B5C848 Instance Manager password encryption is the same as that used by MySQL Server. It is a one-way operation; no means are provided for decrypting encrypted passwords. Instance Manager accounts differ somewhat from MySQL Server accounts: * MySQL Server accounts are associated with a host name, user name, and password (see *Note user-names::). * Instance Manager accounts are associated with a user name and password only. This means that a client can connect to Instance Manager with a given user name from any host. To limit connections so that clients can connect only from the local host, start Instance Manager with the `--bind-address=127.0.0.1' option so that it listens only to the local network interface. Remote clients will not be able to connect. Local clients can connect like this: shell> mysql -h 127.0.0.1 -P 2273 Before MySQL 5.1.12, the only option for creating password file entries is `--passwd', which causes Instance Manager to prompt for user name and password values and display the resulting entry. You can save the output in the `/etc/mysqlmanager.passwd' password file to store it. Here is an example: shell> mysqlmanager --passwd >> /etc/mysqlmanager.passwd Creating record for new user. Enter user name: mike Enter password: mikepass Re-type password: mikepass At the prompts, enter the user name and password for the new Instance Manager user. You must enter the password twice. It does not echo to the screen, so double entry guards against entering a different password than you intend (if the two passwords do not match, no entry is generated). The preceding command causes the following line to be added to `/etc/mysqlmanager.passwd': mike:*BBF1F551DD9DD96A01E66EC7DDC073911BAD17BA Use of the `--password' option fails if `mysqlmanager' is invoked directly from an IBM 5250 terminal. To work around this, use a command like the following from the command line to generate the password entry: shell> mysql -B --skip-column-name \ -e 'SELECT CONCAT("USER_NAME",":",PASSWORD("PASS_VAL"));' The output from the command can be used an entry in the `/etc/mysqlmanager.passwd' file. Beginning with MySQL 5.1.12, the `--passwd' option is renamed to `--print-password-line' and there are several other options for managing user accounts from the command line. For example, the `--username' and `--password' options are available on the command line for specifying the user name and password for an account entry. You can use them to generate an entry with no prompting like this (type the command on a single line): shell> mysqlmanager --print-password-line --username=mike --password=mikepass >> /etc/mysqlmanager.passwd If you omit the `--username' or `--password' option, Instance Manager prompts for the required value. `--print-password-line' causes Instance Manager to send the resulting account entry to its output, which you can append to the password file. The following list describes other account-management options that cause Instance Manager to operate directly on the password file. (These options make Instance Manager scriptable for account-management purposes.) For operations on the password file to succeed, the file must exist and it must be accessible by Instance Manager. (The exception is `--clean-password-file', which creates the file if it does not exist. Alternatively, if there is no password file, manually create it as an empty file and ensure that its ownership and access modes permit it to be read and written by Instance Manager.) The default password file is used unless you specify a `--password-file' option. To ensure consistent treatment of the password file, it should be owned by the system account that you use for running Instance Manager to manage server instances, and you should invoke it from that account when you use it to manage accounts in the password file. * Create a new user: mysqlmanager --add-user --username=USER_NAME [--password=PASSWORD] This command adds a new entry with the given user name and password to the password file. The `--username' (or `-u') option is required. `mysqlmanager' prompts for the password if it is not given on the command line with the `--password' (or `-p') option. The command fails if the user already exists. * Drop an existing user: mysqlmanager --drop-user --username=USER_NAME This command removes the entry with the given user name from the password file. The user name is required. The command fails if the user does not exist. * Change the password for an existing user: mysqlmanager --edit-user --username=USER_NAME [--password=PASSWORD] This command changes the given user's password in the password file. The user name is required. `mysqlmanager' prompts for the password it is not given on the command line. The command fails if the user does not exist. * List existing users: mysqlmanager --list-users This command lists the user names of the accounts in the password file. * Check the password file: mysqlmanager --check-password-file This command performs a consistency and validity check of the password file. The command fails if there is something wrong with the file. * Empty the password file: mysqlmanager --clean-password-file This command empties the password file, which has the effect of dropping all users listed in it. The option creates the password file if it does not exist, so it can be used to initialize a new password file to be used for other account-management operations. Take care not to use this option to reinitialize a file containing accounts that you do not want to drop.  File: manual.info, Node: instance-manager-security-monitoring, Next: instance-manager-security, Prev: instance-manager-security-passwords, Up: instance-manager 5.6.10.5 MySQL Server Instance Status Monitoring ................................................ *Important*: MySQL Instance Manager has been deprecated and is removed in MySQL 5.5. To monitor the status of each guarded server instance, the MySQL Instance Manager attempts to connect to the instance at regular intervals using the `MySQL_Instance_Manager@localhost' user account with a password of `check_connection'. You are _not_ required to create this account for MySQL Server; in fact, it is expected that it will not exist. Instance Manager can tell that a server is operational if the server accepts the connection attempt but refuses access for the account by returning a login error. However, these failed connection attempts are logged by the server to its general query log (see *Note query-log::). Instance Manager also attempts a connection to nonguarded server instances when you use the `SHOW INSTANCES' or `SHOW INSTANCE STATUS' command. This is the only status monitoring done for nonguarded instances. Instance Manager knows if a server instance fails at startup because it receives a status from the attempt. For an instance that starts but later crashes, Instance Manager receives a signal because it is the parent process of the instance. Beginning with MySQL 5.1.12, Instance Manager tracks instance states so that it can determine which commands are permitted for each instance. For example, commands that modify an instance's configuration are permitted only while the instance is offline. Each instance is in one of the states described in the following table. Guarded instances can be in any of the states. Nonguarded instances can only be offline or online. Instance state information is displayed in the `status' column of the `SHOW INSTANCES' and `SHOW INSTANCE STATUS' commands. State Meaning `offline' The instance has not been started and is not running. `starting' The instance is starting (initializing). Nonguarded instances cannot be in this state. A nonguarded instance goes directly from offline to online. `stopping' The instance is stopping. Nonguarded instances cannot be in this state. A nonguarded instance goes directly from online to offline, or stays offline if startup fails. `online' The instance has started and is running. `failed' The instance was online but it crashed and is being restarted by Instance Manager, or else the instance failed to start at all and Instance Manager is again attempting to start it. Nonguarded instances cannot be in this state. `crashed' Instance Manager failed to start the instance after several attempts. (Instance Manager will try again later.) Nonguarded instances cannot be in this state. `abandoned' Instance Manager was not able to start the instance, has given up, and will make no further attempts until instructed otherwise. To tell Instance Manager to try again, you must first use `STOP INSTANCE' to put the instance in offline state, and then use `START INSTANCE' to start the instance. If it is necessary to make configuration changes for the instance, you must do so after putting the instance offline and before starting it. (Instance Manager accepts configuration-changing commands only for offline instances.) Nonguarded instances cannot be in this state.  File: manual.info, Node: instance-manager-security, Next: instance-manager-commands, Prev: instance-manager-security-monitoring, Up: instance-manager 5.6.10.6 Connecting to MySQL Instance Manager ............................................. *Important*: MySQL Instance Manager has been deprecated and is removed in MySQL 5.5. After you set up a password file for the MySQL Instance Manager and Instance Manager is running, you can connect to it. The MySQL client/server protocol is used to communicate with the Instance Manager. For example, you can connect to it using the standard *Note `mysql': mysql. client program: shell> mysql --port=2273 --host=im.example.org --user=mysql --password Instance Manager supports the version of the MySQL client/server protocol used by the client tools and libraries distributed with MySQL 4.1 or later, so other programs that use the MySQL C API also can connect to it.  File: manual.info, Node: instance-manager-commands, Prev: instance-manager-security, Up: instance-manager 5.6.10.7 MySQL Instance Manager Commands ........................................ *Important*: MySQL Instance Manager has been deprecated and is removed in MySQL 5.5. After you connect to MySQL Instance Manager, you can issue commands. The following general principles apply to Instance Manager command execution: * Commands that take an instance name fail if the name is not a valid instance name. * Commands that take an instance name (other than `CREATE INSTANCE') fail if the instance does not exist. * As of MySQL 5.1.12, commands for an instance require that the instance be in an appropriate state. You cannot configure or start an instance that is not offline. You cannot start an instance that is online. * Instance Manager maintains information about instance configuration in an internal (in-memory) cache. Initially, this information comes from the configuration file if it exists, but some commands change the configuration of an instance. Commands that modify the configuration file fail if the file does not exist or is not accessible to Instance Manager. As of MySQL 5.1.12, configuration-changing commands modify both the in-memory cache and the server instance section recorded in the configuration file to maintain consistency between them. For this to occur, the instance must be offline and the configuration file must be accessible and not malformed. If the configuration file cannot be updated, the command fails and the cache remains unchanged. * On Windows, the standard file is `my.ini' in the directory where Instance Manager is installed. On Unix, the standard configuration file is `/etc/my.cnf'. To specify a different configuration file, start Instance Manager with the `--defaults-file' option. * If a `[mysqld]' instance section exists in the configuration file, it must not contain any Instance Manager-specific options (see *Note instance-manager-configuration-files::). Therefore, you must not add any of these options if you change the configuration for an instance named `mysqld'. The following list describes the commands that Instance Manager accepts, with examples. * `CREATE INSTANCE INSTANCE_NAME [OPTION_NAME[=OPTION_VALUE], ...]' This command configures a new instance by creating an `[INSTANCE_NAME]' section in the configuration file. The command fails if INSTANCE_NAME is not a valid instance name or the instance already exists. The created section instance is empty if no options are given. Otherwise, the options are added to the section. Options should be given in the same format used when you write options in option files. (See *Note option-files:: for a description of the permissible syntax.) If you specify multiple options, separate them by commas. For example, to create an instance section named `[mysqld98]', you might write something like this were you to modify the configuration file directly: [mysqld98] basedir=/var/mysql98 To achieve the same effect using `CREATE INSTANCE', issue this command to Instance Manager: mysql> CREATE INSTANCE mysqld98 basedir="/var/mysql98"; Query OK, 0 rows affected (0,00 sec) `CREATE INSTANCE' creates the instance but does not start it. If the instance name is the (deprecated) name `mysqld', the option list cannot include any options that are specific to Instance Manager, such as `nonguarded' (see *Note instance-manager-configuration-files::). This command was added in MySQL 5.1.12. * `DROP INSTANCE INSTANCE_NAME' This command removes the configuration for INSTANCE_NAME from the configuration file. mysql> DROP INSTANCE mysqld98; Query OK, 0 rows affected (0,00 sec) The command fails if INSTANCE_NAME is not a valid instance name, the instance does not exist, or is not offline. This command was added in MySQL 5.1.12. * `START INSTANCE INSTANCE_NAME' This command attempts to start an offline instance. The command is asynchronous; it does not wait for the instance to start. mysql> START INSTANCE mysqld4; Query OK, 0 rows affected (0,00 sec) * `STOP INSTANCE INSTANCE_NAME' This command attempts to stop an instance. The command is synchronous; it waits for the instance to stop. mysql> STOP INSTANCE mysqld4; Query OK, 0 rows affected (0,00 sec) * `SHOW INSTANCES' Shows the names and status of all loaded instances. mysql> SHOW INSTANCES; +---------------+---------+ | instance_name | status | +---------------+---------+ | mysqld3 | offline | | mysqld4 | online | | mysqld2 | offline | +---------------+---------+ * `SHOW INSTANCE STATUS INSTANCE_NAME' Shows status and version information for an instance. mysql> SHOW INSTANCE STATUS mysqld3; +---------------+--------+---------+ | instance_name | status | version | +---------------+--------+---------+ | mysqld3 | online | unknown | +---------------+--------+---------+ * `SHOW INSTANCE OPTIONS INSTANCE_NAME' Shows the options used by an instance. mysql> SHOW INSTANCE OPTIONS mysqld3; +---------------+---------------------------------------------------+ | option_name | value | +---------------+---------------------------------------------------+ | instance_name | mysqld3 | | mysqld-path | /home/cps/mysql/trees/mysql-4.1/sql/mysqld | | port | 3309 | | socket | /tmp/mysql.sock3 | | pid-file | hostname.pid3 | | datadir | /home/cps/mysql_data/data_dir1/ | | language | /home/cps/mysql/trees/mysql-4.1/sql/share/english | +---------------+---------------------------------------------------+ * `SHOW INSTANCE_NAME LOG FILES' The command lists all log files used by the instance. The result set contains the path to the log file and the log file size. If no log file path is specified in the instance section of the configuration file (for example, `log=/var/mysql.log'), the Instance Manager tries to guess its placement. If Instance Manager is unable to guess the log file placement you should specify the log file location explicitly by using a log option in the appropriate instance section of the configuration file. mysql> SHOW mysqld LOG FILES; +-------------+------------------------------------+----------+ | Logfile | Path | Filesize | +-------------+------------------------------------+----------+ | ERROR LOG | /home/cps/var/mysql/owlet.err | 9186 | | GENERAL LOG | /home/cps/var/mysql/owlet.log | 471503 | | SLOW LOG | /home/cps/var/mysql/owlet-slow.log | 4463 | +-------------+------------------------------------+----------+ `SHOW ... LOG FILES' displays information only about log files. If a server instance uses log tables (see *Note log-destinations::), no information about those tables is shown. Log options are described in *Note server-options::. * `SHOW INSTANCE_NAME LOG {ERROR | SLOW | GENERAL} SIZE[,OFFSET_FROM_END]' This command retrieves a portion of the specified log file. Because most users are interested in the latest log messages, the SIZE parameter defines the number of bytes to retrieve from the end of the log. To retrieve data from the middle of the log file, specify the optional OFFSET_FROM_END parameter. The following example retrieves 21 bytes of data, starting 23 bytes before the end of the log file and ending 2 bytes before the end: mysql> SHOW mysqld LOG GENERAL 21, 2; +---------------------+ | Log | +---------------------+ | using password: YES | +---------------------+ * `SET INSTANCE_NAME.OPTION_NAME[=OPTION_VALUE]' This command edits the specified instance's configuration section to change or add instance options. The option is added to the section is it is not already present. Otherwise, the new setting replaces the existing one. mysql> SET mysqld2.port=3322; Query OK, 0 rows affected (0.00 sec) As of MySQL 5.1.12, you can specify multiple options (separated by commas), and `SET' can be used only for offline instances. Each option must indicate the instance name: mysql> SET mysqld2.port=3322, mysqld3.nonguarded; Query OK, 0 rows affected (0.00 sec) Before MySQL 5.1.12, only a single option can be specified. Also, changes made to the configuration file do not take effect until the MySQL server is restarted. In addition, these changes are not stored in the instance manager's local cache of instance settings until a `FLUSH INSTANCES' command is executed. * `UNSET INSTANCE_NAME.OPTION_NAME' This command removes an option from an instance's configuration section. mysql> UNSET mysqld2.port; Query OK, 0 rows affected (0.00 sec) As of MySQL 5.1.12, you can specify multiple options (separated by commas), and `UNSET' can be used only for offline instances. Each option must indicate the instance name: mysql> UNSET mysqld2.port, mysqld4.nonguarded; Query OK, 0 rows affected (0.00 sec) Before MySQL 5.1.12, only a single option can be specified. Also, changes made to the configuration file do not take effect until the MySQL server is restarted. In addition, these changes are not stored in the instance manager's local cache of instance settings until a `FLUSH INSTANCES' command is executed. * `FLUSH INSTANCES' As of MySQL 5.1.12, `FLUSH INSTANCES' cannot be used unless all instances are offline. The command causes Instance Manager to reread the configuration file, update its in-memory configuration cache, and start any guarded instances. Before MySQL 5.1.12, this command forces Instance Manager reread the configuration file and to refresh internal structures. This command should be performed after editing the configuration file. The command does not restart instances. mysql> FLUSH INSTANCES; Query OK, 0 rows affected (0.04 sec)  File: manual.info, Node: mysql-convert-table-format, Next: mysql-find-rows, Prev: instance-manager, Up: programs-admin-utils 5.6.11 `mysql_convert_table_format' -- Convert Tables to Use a Given Storage Engine ----------------------------------------------------------------------------------- *Note `mysql_convert_table_format': mysql-convert-table-format. converts the tables in a database to use a particular storage engine (`MyISAM' by default). *Note `mysql_convert_table_format': mysql-convert-table-format. is written in Perl and requires that the `DBI' and `DBD::mysql' Perl modules be installed (see *Note perl-support::). Invoke *Note `mysql_convert_table_format': mysql-convert-table-format. like this: shell> mysql_convert_table_format [OPTIONS]DB_NAME The DB_NAME argument indicates the database containing the tables to be converted. *Note `mysql_convert_table_format': mysql-convert-table-format. supports the options described in the following list. * `--help' Display a help message and exit. * `--force' Continue even if errors occur. * `--host=HOST_NAME' Connect to the MySQL server on the given host. * `--password=PASSWORD' The password to use when connecting to the server. Note that the password value is not optional for this option, unlike for other MySQL programs. Specifying a password on the command line should be considered insecure. See *Note password-security-user::. You can use an option file to avoid giving the password on the command line. * `--port=PORT_NUM' The TCP/IP port number to use for the connection. * `--socket=PATH' For connections to `localhost', the Unix socket file to use. * `--type=ENGINE_NAME' Specify the storage engine that the tables should be converted to use. The default is `MyISAM' if this option is not given. * `--user=USER_NAME' The MySQL user name to use when connecting to the server. * `--verbose' Verbose mode. Print more information about what the program does. * `--version' Display version information and exit.  File: manual.info, Node: mysql-find-rows, Next: mysql-fix-extensions, Prev: mysql-convert-table-format, Up: programs-admin-utils 5.6.12 `mysql_find_rows' -- Extract SQL Statements from Files ------------------------------------------------------------- *Note `mysql_find_rows': mysql-find-rows. reads files containing SQL statements and extracts statements that match a given regular expression or that contain `USE DB_NAME' or *Note `SET': set-option. statements. The utility was written for use with update log files (as used prior to MySQL 5.0) and as such expects statements to be terminated with semicolon (`;') characters. It may be useful with other files that contain SQL statements as long as statements are terminated with semicolons. Invoke *Note `mysql_find_rows': mysql-find-rows. like this: shell> mysql_find_rows [OPTIONS] [FILE_NAME ...] Each FILE_NAME argument should be the name of file containing SQL statements. If no file names are given, *Note `mysql_find_rows': mysql-find-rows. reads the standard input. Examples: mysql_find_rows --regexp=problem_table --rows=20 < update.log mysql_find_rows --regexp=problem_table update-log.1 update-log.2 *Note `mysql_find_rows': mysql-find-rows. supports the following options: * `--help', `--Information' Display a help message and exit. * `--regexp=PATTERN' Display queries that match the pattern. * `--rows=N' Quit after displaying N queries. * `--skip-use-db' Do not include `USE DB_NAME' statements in the output. * `--start_row=N' Start output from this row.  File: manual.info, Node: mysql-fix-extensions, Next: mysql-setpermission, Prev: mysql-find-rows, Up: programs-admin-utils 5.6.13 `mysql_fix_extensions' -- Normalize Table File Name Extensions --------------------------------------------------------------------- *Note `mysql_fix_extensions': mysql-fix-extensions. converts the extensions for `MyISAM' (or `ISAM') table files to their canonical forms. It looks for files with extensions matching any lettercase variant of `.frm', `.myd', `.myi', `.isd', and `.ism' and renames them to have extensions of `.frm', `.MYD', `.MYI', `.ISD', and `.ISM', respectively. This can be useful after transferring the files from a system with case-insensitive file names (such as Windows) to a system with case-sensitive file names. Invoke *Note `mysql_fix_extensions': mysql-fix-extensions. like this, where DATA_DIR is the path name to the MySQL data directory. shell> mysql_fix_extensions DATA_DIR  File: manual.info, Node: mysql-setpermission, Next: mysql-waitpid, Prev: mysql-fix-extensions, Up: programs-admin-utils 5.6.14 `mysql_setpermission' -- Interactively Set Permissions in Grant Tables ----------------------------------------------------------------------------- *Note `mysql_setpermission': mysql-setpermission. is a Perl script that was originally written and contributed by Luuk de Boer. It interactively sets permissions in the MySQL grant tables. *Note `mysql_setpermission': mysql-setpermission. is written in Perl and requires that the `DBI' and `DBD::mysql' Perl modules be installed (see *Note perl-support::). Invoke *Note `mysql_setpermission': mysql-setpermission. like this: shell> mysql_setpermission [OPTIONS] OPTIONS should be either `--help' to display the help message, or options that indicate how to connect to the MySQL server. The account used when you connect determines which permissions you have when attempting to modify existing permissions in the grant tables. `mysql_setpermissions' also reads options from the `[client]' and `[perl]' groups in the `.my.cnf' file in your home directory, if the file exists. *Note `mysql_setpermission': mysql-setpermission. supports the following options: * `--help' Display a help message and exit. * `--host=HOST_NAME' Connect to the MySQL server on the given host. * `--password=PASSWORD' The password to use when connecting to the server. Note that the password value is not optional for this option, unlike for other MySQL programs. Specifying a password on the command line should be considered insecure. See *Note password-security-user::. You can use an option file to avoid giving the password on the command line. * `--port=PORT_NUM' The TCP/IP port number to use for the connection. * `--socket=PATH' For connections to `localhost', the Unix socket file to use. * `--user=USER_NAME' The MySQL user name to use when connecting to the server.  File: manual.info, Node: mysql-waitpid, Next: mysql-zap, Prev: mysql-setpermission, Up: programs-admin-utils 5.6.15 `mysql_waitpid' -- Kill Process and Wait for Its Termination ------------------------------------------------------------------- *Note `mysql_waitpid': mysql-waitpid. signals a process to terminate and waits for the process to exit. It uses the `kill()' system call and Unix signals, so it runs on Unix and Unix-like systems. Invoke *Note `mysql_waitpid': mysql-waitpid. like this: shell> mysql_waitpid [OPTIONS] PID WAIT_TIME *Note `mysql_waitpid': mysql-waitpid. sends signal 0 to the process identified by PID and waits up to WAIT_TIME seconds for the process to terminate. PID and WAIT_TIME must be positive integers. If process termination occurs within the wait time or the process does not exist, *Note `mysql_waitpid': mysql-waitpid. returns 0. Otherwise, it returns 1. If the `kill()' system call cannot handle signal 0, `mysql_waitpid()' uses signal 1 instead. *Note `mysql_waitpid': mysql-waitpid. supports the following options: * `--help', `-?', `-I' Display a help message and exit. * `--verbose', `-v' Verbose mode. Display a warning if signal 0 could not be used and signal 1 is used instead. * `--version', `-V' Display version information and exit.  File: manual.info, Node: mysql-zap, Prev: mysql-waitpid, Up: programs-admin-utils 5.6.16 `mysql_zap' -- Kill Processes That Match a Pattern --------------------------------------------------------- *Note `mysql_zap': mysql-zap. kills processes that match a pattern. It uses the `ps' command and Unix signals, so it runs on Unix and Unix-like systems. Invoke *Note `mysql_zap': mysql-zap. like this: shell> mysql_zap [-SIGNAL] [-?Ift] PATTERN A process matches if its output line from the `ps' command contains the pattern. By default, *Note `mysql_zap': mysql-zap. asks for confirmation for each process. Respond `y' to kill the process, or `q' to exit *Note `mysql_zap': mysql-zap. For any other response, *Note `mysql_zap': mysql-zap. does not attempt to kill the process. If the `-SIGNAL' option is given, it specifies the name or number of the signal to send to each process. Otherwise, *Note `mysql_zap': mysql-zap. tries first with `TERM' (signal 15) and then with *Note `KILL': kill. (signal 9). *Note `mysql_zap': mysql-zap. supports the following additional options: * `--help', `-?', `-I' Display a help message and exit. * `-f' Force mode. *Note `mysql_zap': mysql-zap. attempts to kill each process without confirmation. * `-t' Test mode. Display information about each process but do not kill it.  File: manual.info, Node: programs-development, Next: programs-miscellaneous, Prev: programs-admin-utils, Up: programs 5.7 MySQL Program Development Utilities ======================================= * Menu: * msql2mysql:: `msql2mysql' --- Convert mSQL Programs for Use with MySQL * mysql-config:: `mysql_config' --- Get Compile Options for Compiling Clients * my-print-defaults:: `my_print_defaults' --- Display Options from Option Files * resolve-stack-dump:: `resolve_stack_dump' --- Resolve Numeric Stack Trace Dump to Symbols This section describes some utilities that you may find useful when developing MySQL programs. In shell scripts, you can use the *Note `my_print_defaults': my-print-defaults. program to parse option files and see what options would be used by a given program. The following example shows the output that *Note `my_print_defaults': my-print-defaults. might produce when asked to show the options found in the `[client]' and `[mysql]' groups: shell> my_print_defaults client mysql --port=3306 --socket=/tmp/mysql.sock --no-auto-rehash Note for developers: Option file handling is implemented in the C client library simply by processing all options in the appropriate group or groups before any command-line arguments. This works well for programs that use the last instance of an option that is specified multiple times. If you have a C or C++ program that handles multiply specified options this way but that doesn't read option files, you need add only two lines to give it that capability. Check the source code of any of the standard MySQL clients to see how to do this. Several other language interfaces to MySQL are based on the C client library, and some of them provide a way to access option file contents. These include Perl and Python. For details, see the documentation for your preferred interface.  File: manual.info, Node: msql2mysql, Next: mysql-config, Prev: programs-development, Up: programs-development 5.7.1 `msql2mysql' -- Convert mSQL Programs for Use with MySQL -------------------------------------------------------------- Initially, the MySQL C API was developed to be very similar to that for the mSQL database system. Because of this, mSQL programs often can be converted relatively easily for use with MySQL by changing the names of the C API functions. The *Note `msql2mysql': msql2mysql. utility performs the conversion of mSQL C API function calls to their MySQL equivalents. *Note `msql2mysql': msql2mysql. converts the input file in place, so make a copy of the original before converting it. For example, use *Note `msql2mysql': msql2mysql. like this: shell> cp client-prog.c client-prog.c.orig shell> msql2mysql client-prog.c client-prog.c converted Then examine `client-prog.c' and make any post-conversion revisions that may be necessary. *Note `msql2mysql': msql2mysql. uses the *Note `replace': replace-utility. utility to make the function name substitutions. See *Note replace-utility::.  File: manual.info, Node: mysql-config, Next: my-print-defaults, Prev: msql2mysql, Up: programs-development 5.7.2 `mysql_config' -- Get Compile Options for Compiling Clients ----------------------------------------------------------------- *Note `mysql_config': mysql-config. provides you with useful information for compiling your MySQL client and connecting it to MySQL. *Note `mysql_config': mysql-config. supports the following options. * `--cflags' Compiler flags to find include files and critical compiler flags and defines used when compiling the `libmysqlclient' library. The options returned are tied to the specific compiler that was used when the library was created and might clash with the settings for your own compiler. Use `--include' for more portable options that contain only include paths. * `--include' Compiler options to find MySQL include files. * `--libmysqld-libs', `--embedded' Libraries and options required to link with the MySQL embedded server. * `--libs' Libraries and options required to link with the MySQL client library. * `--libs_r' Libraries and options required to link with the thread-safe MySQL client library. * `--plugindir' The default plugin directory path name, defined when configuring MySQL. This option was added in MySQL 5.1.24. * `--port' The default TCP/IP port number, defined when configuring MySQL. * `--socket' The default Unix socket file, defined when configuring MySQL. * `--version' Version number for the MySQL distribution. If you invoke *Note `mysql_config': mysql-config. with no options, it displays a list of all options that it supports, and their values: shell> mysql_config Usage: /usr/local/mysql/bin/mysql_config [options] Options: --cflags [-I/usr/local/mysql/include/mysql -mcpu=pentiumpro] --include [-I/usr/local/mysql/include/mysql] --libs [-L/usr/local/mysql/lib/mysql -lmysqlclient -lz -lcrypt -lnsl -lm -L/usr/lib -lssl -lcrypto] --libs_r [-L/usr/local/mysql/lib/mysql -lmysqlclient_r -lpthread -lz -lcrypt -lnsl -lm -lpthread] --socket [/tmp/mysql.sock] --port [3306] --version [4.0.16] --libmysqld-libs [-L/usr/local/mysql/lib/mysql -lmysqld -lpthread -lz -lcrypt -lnsl -lm -lpthread -lrt] You can use *Note `mysql_config': mysql-config. within a command line to include the value that it displays for a particular option. For example, to compile a MySQL client program, use *Note `mysql_config': mysql-config. as follows: shell> CFG=/usr/local/mysql/bin/mysql_config shell> sh -c "gcc -o progname `$CFG --include` progname.c `$CFG --libs`" When you use *Note `mysql_config': mysql-config. this way, be sure to invoke it within backtick (```'') characters. That tells the shell to execute it and substitute its output into the surrounding command.  File: manual.info, Node: my-print-defaults, Next: resolve-stack-dump, Prev: mysql-config, Up: programs-development 5.7.3 `my_print_defaults' -- Display Options from Option Files -------------------------------------------------------------- *Note `my_print_defaults': my-print-defaults. displays the options that are present in option groups of option files. The output indicates what options will be used by programs that read the specified option groups. For example, the *Note `mysqlcheck': mysqlcheck. program reads the `[mysqlcheck]' and `[client]' option groups. To see what options are present in those groups in the standard option files, invoke *Note `my_print_defaults': my-print-defaults. like this: shell> my_print_defaults mysqlcheck client --user=myusername --password=secret --host=localhost The output consists of options, one per line, in the form that they would be specified on the command line. *Note `my_print_defaults': my-print-defaults. supports the following options. * `--help', `-?' Display a help message and exit. * `--config-file=FILE_NAME', `--defaults-file=FILE_NAME', `-c FILE_NAME' Read only the given option file. * `--debug=DEBUG_OPTIONS', `-# DEBUG_OPTIONS' Write a debugging log. A typical DEBUG_OPTIONS string is `'d:t:o,FILE_NAME''. The default is `'d:t:o,/tmp/my_print_defaults.trace''. * `--defaults-extra-file=FILE_NAME', `--extra-file=FILE_NAME', `-e FILE_NAME' Read this option file after the global option file but (on Unix) before the user option file. * `--defaults-group-suffix=SUFFIX', `-g SUFFIX' In addition to the groups named on the command line, read groups that have the given suffix. * `--no-defaults', `-n' Return an empty string. * `--verbose', `-v' Verbose mode. Print more information about what the program does. * `--version', `-V' Display version information and exit.  File: manual.info, Node: resolve-stack-dump, Prev: my-print-defaults, Up: programs-development 5.7.4 `resolve_stack_dump' -- Resolve Numeric Stack Trace Dump to Symbols ------------------------------------------------------------------------- *Note `resolve_stack_dump': resolve-stack-dump. resolves a numeric stack dump to symbols. Invoke *Note `resolve_stack_dump': resolve-stack-dump. like this: shell> resolve_stack_dump [OPTIONS] SYMBOLS_FILE [NUMERIC_DUMP_FILE] The symbols file should include the output from the `nm --numeric-sort mysqld' command. The numeric dump file should contain a numeric stack track from *Note `mysqld': mysqld. If no numeric dump file is named on the command line, the stack trace is read from the standard input. *Note `resolve_stack_dump': resolve-stack-dump. supports the following options. * `--help', `-h' Display a help message and exit. * `--numeric-dump-file=FILE_NAME', `-n FILE_NAME' Read the stack trace from the given file. * `--symbols-file=FILE_NAME', `-s FILE_NAME' Use the given symbols file. * `--version', `-V' Display version information and exit.  File: manual.info, Node: programs-miscellaneous, Prev: programs-development, Up: programs 5.8 Miscellaneous Programs ========================== * Menu: * perror:: `perror' --- Explain Error Codes * replace-utility:: `replace' --- A String-Replacement Utility * resolveip:: `resolveip' --- Resolve Host name to IP Address or Vice Versa  File: manual.info, Node: perror, Next: replace-utility, Prev: programs-miscellaneous, Up: programs-miscellaneous 5.8.1 `perror' -- Explain Error Codes ------------------------------------- For most system errors, MySQL displays, in addition to an internal text message, the system error code in one of the following styles: message ... (errno: #) message ... (Errcode: #) You can find out what the error code means by examining the documentation for your system or by using the *Note `perror': perror. utility. *Note `perror': perror. prints a description for a system error code or for a storage engine (table handler) error code. Invoke *Note `perror': perror. like this: shell> perror [OPTIONS] ERRORCODE ... Example: shell> perror 13 64 OS error code 13: Permission denied OS error code 64: Machine is not on the network To obtain the error message for a MySQL Cluster error code, invoke *Note `perror': perror. with the `--ndb' option: shell> perror --ndb ERRORCODE Note that the meaning of system error messages may be dependent on your operating system. A given error code may mean different things on different operating systems. *Note `perror': perror. supports the following options. * `--help', `--info', `-I', `-?' Display a help message and exit. * `--ndb' Print the error message for a MySQL Cluster error code. * `--silent', `-s' Silent mode. Print only the error message. * `--verbose', `-v' Verbose mode. Print error code and message. This is the default behavior. * `--version', `-V' Display version information and exit.  File: manual.info, Node: replace-utility, Next: resolveip, Prev: perror, Up: programs-miscellaneous 5.8.2 `replace' -- A String-Replacement Utility ----------------------------------------------- The *Note `replace': replace-utility. utility program changes strings in place in files or on the standard input. Invoke *Note `replace': replace-utility. in one of the following ways: shell> replace FROM TO [FROM TO] ... -- FILE_NAME [FILE_NAME] ... shell> replace FROM TO [FROM TO] ... < FILE_NAME FROM represents a string to look for and TO represents its replacement. There can be one or more pairs of strings. Use the `--' option to indicate where the string-replacement list ends and the file names begin. In this case, any file named on the command line is modified in place, so you may want to make a copy of the original before converting it. REPLACE prints a message indicating which of the input files it actually modifies. If the `--' option is not given, *Note `replace': replace-utility. reads the standard input and writes to the standard output. *Note `replace': replace-utility. uses a finite state machine to match longer strings first. It can be used to swap strings. For example, the following command swaps `a' and `b' in the given files, `file1' and `file2': shell> replace a b b a -- file1 file2 ... The *Note `replace': replace-utility. program is used by *Note `msql2mysql': msql2mysql. See *Note msql2mysql::. *Note `replace': replace-utility. supports the following options. * `-?', `-I' Display a help message and exit. * `-#DEBUG_OPTIONS' Enable debugging. * `-s' Silent mode. Print less information what the program does. * `-v' Verbose mode. Print more information about what the program does. * `-V' Display version information and exit.  File: manual.info, Node: resolveip, Prev: replace-utility, Up: programs-miscellaneous 5.8.3 `resolveip' -- Resolve Host name to IP Address or Vice Versa ------------------------------------------------------------------ The *Note `resolveip': resolveip. utility resolves host names to IP addresses and vice versa. Invoke *Note `resolveip': resolveip. like this: shell> resolveip [OPTIONS] {HOST_NAME|IP-ADDR} ... *Note `resolveip': resolveip. supports the following options. * `--help', `--info', `-?', `-I' Display a help message and exit. * `--silent', `-s' Silent mode. Produce less output. * `--version', `-V' Display version information and exit.  File: manual.info, Node: server-administration, Next: backup-and-recovery, Prev: programs, Up: Top 6 MySQL Server Administration ***************************** * Menu: * mysqld-server:: The MySQL Server * server-logs:: MySQL Server Logs * security:: General Security Issues * privilege-system:: The MySQL Access Privilege System * user-account-management:: MySQL User Account Management * multiple-servers:: Running Multiple MySQL Instances on One Machine MySQL Server (*Note `mysqld': mysqld.) is the main program that does most of the work in a MySQL installation. This section provides an overview of MySQL Server and covers topics that deal with administering a MySQL installation: * Server configuration * The server log files * Security issues and user-account management * Management of multiple servers on a single machine  File: manual.info, Node: mysqld-server, Next: server-logs, Prev: server-administration, Up: server-administration 6.1 The MySQL Server ==================== * Menu: * mysqld-option-tables:: Server Option and Variable Reference * server-options:: Server Command Options * server-system-variables:: Server System Variables * using-system-variables:: Using System Variables * server-status-variables:: Server Status Variables * server-sql-mode:: Server SQL Modes * server-plugins:: Server Plugins * server-side-help-support:: Server-Side Help * server-signal-response:: Server Response to Signals * server-shutdown:: The Shutdown Process *Note `mysqld': mysqld. is the MySQL server. The following discussion covers these MySQL server configuration topics: * Startup options that the server supports * Server system variables * Server status variables * How to set the server SQL mode * The server shutdown process *Note*: Not all storage engines are supported by all MySQL server binaries and configurations. To find out how to determine which storage engines your MySQL server installation supports, see *Note show-engines::.  File: manual.info, Node: mysqld-option-tables, Next: server-options, Prev: mysqld-server, Up: mysqld-server 6.1.1 Server Option and Variable Reference ------------------------------------------ The following table provides a list of all the command line options, server and status variables applicable within `mysqld'. The table lists command-line options (Cmd-line), options valid in configuration files (Option file), server system variables (System Var), and status variables (Status var) in one unified list, with notification of where each option/variable is valid. If a server option set on the command line or in an option file differs from the name of the corresponding server system or status variable, the variable name is noted immediately below the corresponding option. For status variables, the scope of the variable is shown (Scope) as either global, session, or both. Please see the corresponding sections for details on setting and using the options and variables. Where appropriate, a direct link to further information on the item as available. For a version of this table that is specific to MySQL Cluster, see *Note mysql-cluster-option-tables::. *Option/Variable Summary* Name Cmd-Line Option file System Var Status Var Var Scope Dynamic abort-slave-event-countYes Yes Aborted_clients Yes Global No Aborted_connects Yes Global No allow-suspicious-udfsYes Yes ansi Yes Yes auto_increment_incrementYes Yes Yes Both Yes auto_increment_offsetYes Yes Yes Both Yes autocommit Yes Yes Yes Session Yes automatic_sp_privileges Yes Global Yes back_log Yes Yes Yes Global No basedir Yes Yes Yes Global No big-tables Yes Yes Session Yes - _Variable_: Yes Session Yes big_tables bind-address Yes Yes Yes Global No Binlog_cache_disk_use Yes Global No binlog_cache_sizeYes Yes Yes Global Yes Binlog_cache_use Yes Global No binlog_direct_non_transactional_updatesYes Yes Yes Both Yes binlog-do-db Yes Yes binlog-format Yes Yes Both Yes - _Variable_: Yes Both Yes binlog_format binlog-ignore-dbYes Yes binlog-row-event-max-sizeYes Yes bootstrap Yes Yes bulk_insert_buffer_sizeYes Yes Yes Both Yes Bytes_received Yes Both No Bytes_sent Yes Both No character_set_client Yes Both Yes character-set-client-handshakeYes Yes character_set_connection Yes Both Yes character_set_database Yes Both Yes This option is dynamic, but only the server should set this information. You should not set the value of this variable manually. character-set-filesystemYes Yes Both Yes - _Variable_: Yes Both Yes character_set_filesystem character_set_results Yes Both Yes character-set-serverYes Yes Both Yes - _Variable_: Yes Both Yes character_set_server character_set_system Yes Global No character-sets-dirYes Yes Global No - _Variable_: Yes Global No character_sets_dir chroot Yes Yes collation_connection Yes Both Yes collation_database Yes Both Yes This option is dynamic, but only the server should set this information. You should not set the value of this variable manually. collation-serverYes Yes Both Yes - _Variable_: Yes Both Yes collation_server Com_admin_commands Yes Both No Com_alter_db Yes Both No Com_alter_db_upgrade Yes Both No Com_alter_event Yes Both No Com_alter_function Yes Both No Com_alter_procedure Yes Both No Com_alter_server Yes Both No Com_alter_table Yes Both No Com_alter_tablespace Yes Both No Com_analyze Yes Both No Com_assign_to_keycache Yes Both No Com_backup_table Yes Both No Com_begin Yes Both No Com_binlog Yes Both No Com_call_procedure Yes Both No Com_change_db Yes Both No Com_change_master Yes Both No Com_check Yes Both No Com_checksum Yes Both No Com_commit Yes Both No Com_create_db Yes Both No Com_create_event Yes Both No Com_create_function Yes Both No Com_create_index Yes Both No Com_create_procedure Yes Both No Com_create_server Yes Both No Com_create_table Yes Both No Com_create_trigger Yes Both No Com_create_udf Yes Both No Com_create_user Yes Both No Com_create_view Yes Both No Com_dealloc_sql Yes Both No Com_delete Yes Both No Com_delete_multi Yes Both No Com_do Yes Both No Com_drop_db Yes Both No Com_drop_event Yes Both No Com_drop_function Yes Both No Com_drop_index Yes Both No Com_drop_procedure Yes Both No Com_drop_server Yes Both No Com_drop_table Yes Both No Com_drop_trigger Yes Both No Com_drop_user Yes Both No Com_drop_view Yes Both No Com_empty_query Yes Both No Com_execute_sql Yes Both No Com_flush Yes Both No Com_grant Yes Both No Com_ha_close Yes Both No Com_ha_open Yes Both No Com_ha_read Yes Both No Com_help Yes Both No Com_insert Yes Both No Com_insert_select Yes Both No Com_install_plugin Yes Both No Com_kill Yes Both No Com_load Yes Both No Com_lock_tables Yes Both No Com_optimize Yes Both No Com_preload_keys Yes Both No Com_prepare_sql Yes Both No Com_purge Yes Both No Com_purge_before_date Yes Both No Com_release_savepoint Yes Both No Com_rename_table Yes Both No Com_rename_user Yes Both No Com_repair Yes Both No Com_replace Yes Both No Com_replace_select Yes Both No Com_reset Yes Both No Com_restore_table Yes Both No Com_revoke Yes Both No Com_revoke_all Yes Both No Com_rollback Yes Both No Com_rollback_to_savepoint Yes Both No Com_savepoint Yes Both No Com_select Yes Both No Com_set_option Yes Both No Com_show_authors Yes Both No Com_show_binlog_events Yes Both No Com_show_binlogs Yes Both No Com_show_charsets Yes Both No Com_show_collations Yes Both No Com_show_column_types Yes Both No Com_show_contributors Yes Both No Com_show_create_db Yes Both No Com_show_create_event Yes Both No Com_show_create_func Yes Both No Com_show_create_proc Yes Both No Com_show_create_table Yes Both No Com_show_create_trigger Yes Both No Com_show_databases Yes Both No Com_show_engine_logs Yes Both No Com_show_engine_mutex Yes Both No Com_show_engine_status Yes Both No Com_show_errors Yes Both No Com_show_events Yes Both No Com_show_fields Yes Both No Com_show_function_code Yes Both No Com_show_function_status Yes Both No Com_show_grants Yes Both No Com_show_keys Yes Both No Com_show_logs Yes Both No Com_show_master_status Yes Both No Com_show_ndb_status Yes Both No Com_show_new_master Yes Both No Com_show_open_tables Yes Both No Com_show_plugins Yes Both No Com_show_privileges Yes Both No Com_show_procedure_code Yes Both No Com_show_procedure_status Yes Both No Com_show_processlist Yes Both No Com_show_profile Yes Both No Com_show_profiles Yes Both No Com_show_slave_hosts Yes Both No Com_show_slave_status Yes Both No Com_show_status Yes Both No Com_show_storage_engines Yes Both No Com_show_table_status Yes Both No Com_show_tables Yes Both No Com_show_triggers Yes Both No Com_show_variables Yes Both No Com_show_warnings Yes Both No Com_slave_start Yes Both No Com_slave_stop Yes Both No Com_stmt_close Yes Both No Com_stmt_execute Yes Both No Com_stmt_fetch Yes Both No Com_stmt_prepare Yes Both No Com_stmt_reprepare Yes Both No Com_stmt_reset Yes Both No Com_stmt_send_long_data Yes Both No Com_truncate Yes Both No Com_uninstall_plugin Yes Both No Com_unlock_tables Yes Both No Com_update Yes Both No Com_update_multi Yes Both No Com_xa_commit Yes Both No Com_xa_end Yes Both No Com_xa_prepare Yes Both No Com_xa_recover Yes Both No Com_xa_rollback Yes Both No Com_xa_start Yes Both No completion_typeYes Yes Yes Both Yes Compression Yes Session No concurrent_insertYes Yes Yes Global Yes connect_timeoutYes Yes Yes Global Yes Connections Yes Global No console Yes Yes core-file Yes Yes Created_tmp_disk_tables Yes Both No Created_tmp_files Yes Global No Created_tmp_tables Yes Both No datadir Yes Yes Yes Global No date_format Yes Both No datetime_format Yes Both No debug Yes Yes Yes Both Yes debug_sync Yes Both Yes debug-sync-timeoutYes Yes default-storage-engineYes Yes Yes Both Yes default-table-typeYes Yes default-time-zoneYes Yes default_week_formatYes Yes Yes Both Yes defaults-extra-fileYes defaults-file Yes defaults-group-suffixYes delay-key-writeYes Yes Global Yes - _Variable_: Yes Global Yes delay_key_write Delayed_errors Yes Global No delayed_insert_limitYes Yes Yes Global Yes Delayed_insert_threads Yes Global No delayed_insert_timeoutYes Yes Yes Global Yes delayed_queue_sizeYes Yes Yes Global Yes Delayed_writes Yes Global No des-key-file Yes Yes disconnect-slave-event-countYes Yes div_precision_incrementYes Yes Yes Both Yes enable-locking Yes Yes enable-named-pipeYes Yes - _Variable_: named_pipe enable-pstack Yes Yes engine-condition-pushdownYes Yes Both Yes - _Variable_: Yes Both Yes engine_condition_pushdown error_count Yes Session No event-schedulerYes Yes Global Yes - _Variable_: Yes Global Yes event_scheduler exit-info Yes Yes expire_logs_daysYes Yes Yes Global Yes external-lockingYes Yes - _Variable_: skip_external_locking *Note Yes Yes federated: federated-storage-engine. flush Yes Yes Yes Global Yes Flush_commands Yes Global No flush_time Yes Yes Yes Global Yes foreign_key_checks Yes Session Yes ft_boolean_syntaxYes Yes Yes Global Yes ft_max_word_lenYes Yes Yes Global No ft_min_word_lenYes Yes Yes Global No ft_query_expansion_limitYes Yes Yes Global No ft_stopword_fileYes Yes Yes Global No gdb Yes Yes general-log Yes Yes Global Yes - _Variable_: Yes Global Yes general_log general_log_fileYes Yes Yes Global Yes group_concat_max_lenYes Yes Yes Both Yes Handler_commit Yes Both No Handler_delete Yes Both No Handler_discover Yes Both No Handler_prepare Yes Both No Handler_read_first Yes Both No Handler_read_key Yes Both No Handler_read_next Yes Both No Handler_read_prev Yes Both No Handler_read_rnd Yes Both No Handler_read_rnd_next Yes Both No Handler_rollback Yes Both No Handler_savepoint Yes Both No Handler_savepoint_rollback Yes Both No Handler_update Yes Both No Handler_write Yes Both No have_archive Yes Global No have_blackhole_engine Yes Global No have_community_features Yes Global No have_compress Yes Global No have_crypt Yes Global No have_csv Yes Global No have_dynamic_loading Yes Global No have_example_engine Yes Global No have_federated_engine Yes Global No have_geometry Yes Global No have_innodb Yes Global No have_isam Yes Global No have_merge_engine Yes Global No have_ndbcluster Yes Global No have_openssl Yes Global No have_partition_engine Yes Global No have_partitioning Yes Global No have_query_cache Yes Global No have_raid Yes Global No have_row_based_replication Yes Global No have_rtree_keys Yes Global No have_ssl Yes Global No have_symlink Yes Global No help Yes Yes hostname Yes Global No identity Yes Session Yes ignore-builtin-innodbYes Yes Global No - _Variable_: Yes Global No ignore_builtin_innodb init_connect Yes Yes Yes Global Yes init-file Yes Yes Global No - _Variable_: Yes Global No init_file init-rpl-role Yes Yes init_slave Yes Yes Yes Global Yes innodb Yes Yes innodb_adaptive_flushingYes Yes Yes Global Yes innodb_adaptive_hash_indexYes Yes Yes Global No innodb_additional_mem_pool_sizeYes Yes Yes Global No innodb_autoextend_incrementYes Yes Yes Global Yes innodb_autoinc_lock_modeYes Yes Yes Global No innodb_buffer_pool_awe_mem_mbYes Yes Yes Global No Innodb_buffer_pool_pages_data Yes Global No Innodb_buffer_pool_pages_dirty Yes Global No Innodb_buffer_pool_pages_flushed Yes Global No Innodb_buffer_pool_pages_free Yes Global No Innodb_buffer_pool_pages_latched Yes Global No Innodb_buffer_pool_pages_misc Yes Global No Innodb_buffer_pool_pages_total Yes Global No Innodb_buffer_pool_read_ahead Yes Global No Innodb_buffer_pool_read_ahead_evicted Yes Global No Innodb_buffer_pool_read_ahead_rnd Yes Global No Innodb_buffer_pool_read_ahead_seq Yes Global No Innodb_buffer_pool_read_requests Yes Global No Innodb_buffer_pool_reads Yes Global No innodb_buffer_pool_sizeYes Yes Yes Global No Innodb_buffer_pool_wait_free Yes Global No Innodb_buffer_pool_write_requests Yes Global No innodb_change_bufferingYes Yes Yes Global Yes innodb_checksumsYes Yes Yes Global No innodb_commit_concurrencyYes Yes Yes Global Yes innodb_concurrency_ticketsYes Yes Yes Global Yes innodb_data_file_pathYes Yes Yes Global No Innodb_data_fsyncs Yes Global No innodb_data_home_dirYes Yes Yes Global No Innodb_data_pending_fsyncs Yes Global No Innodb_data_pending_reads Yes Global No Innodb_data_pending_writes Yes Global No Innodb_data_read Yes Global No Innodb_data_reads Yes Global No Innodb_data_writes Yes Global No Innodb_data_written Yes Global No Innodb_dblwr_pages_written Yes Global No Innodb_dblwr_writes Yes Global No innodb_doublewriteYes Yes Yes Global No innodb_fast_shutdownYes Yes Yes Global Yes innodb_file_formatYes Yes Yes Global Yes innodb_file_format_checkYes Yes Yes Global Yes innodb_file_io_threadsYes Yes Yes Global No innodb_file_per_tableYes Yes Yes Global No innodb_flush_log_at_trx_commitYes Yes Yes Global Yes innodb_flush_methodYes Yes Yes Global No innodb_force_recoveryYes Yes Yes Global No Innodb_have_atomic_builtins Yes Global No innodb_io_capacityYes Yes Yes Global No innodb_lock_wait_timeoutYes Yes Yes Both Yes innodb_locks_unsafe_for_binlogYes Yes Yes Global No innodb_log_arch_dirYes Yes Yes Global No innodb_log_archiveYes Yes Yes Global No innodb_log_buffer_sizeYes Yes Yes Global No innodb_log_file_sizeYes Yes Yes Global No innodb_log_files_in_groupYes Yes Yes Global No innodb_log_group_home_dirYes Yes Yes Global No Innodb_log_waits Yes Global No Innodb_log_write_requests Yes Global No Innodb_log_writes Yes Global No innodb_max_dirty_pages_pctYes Yes Yes Global Yes innodb_max_purge_lagYes Yes Yes Global Yes innodb_mirrored_log_groupsYes Yes Yes Global No innodb_old_blocks_pctYes Yes Yes Global Yes innodb_old_blocks_timeYes Yes Yes Global Yes innodb_open_filesYes Yes Yes Global No Innodb_os_log_fsyncs Yes Global No Innodb_os_log_pending_fsyncs Yes Global No Innodb_os_log_pending_writes Yes Global No Innodb_os_log_written Yes Global No Innodb_page_size Yes Global No Innodb_pages_created Yes Global No Innodb_pages_read Yes Global No Innodb_pages_written Yes Global No innodb_read_ahead_thresholdYes Yes Yes Global Yes innodb_read_io_threadsYes Yes Yes Global No innodb_replication_delayYes Yes Yes Global Yes innodb_rollback_on_timeoutYes Yes Yes Global No Innodb_row_lock_current_waits Yes Global No Innodb_row_lock_time Yes Global No Innodb_row_lock_time_avg Yes Global No Innodb_row_lock_time_max Yes Global No Innodb_row_lock_waits Yes Global No Innodb_rows_deleted Yes Global No Innodb_rows_inserted Yes Global No Innodb_rows_read Yes Global No Innodb_rows_updated Yes Global No innodb_spin_wait_delayYes Yes Yes Global Yes innodb_stats_on_metadataYes Yes Yes Global Yes innodb_stats_sample_pagesYes Yes Yes Global Yes innodb-status-fileYes Yes innodb_strict_modeYes Yes Yes Both Yes innodb_support_xaYes Yes Yes Both Yes innodb_sync_spin_loopsYes Yes Yes Global Yes innodb_table_locksYes Yes Yes Both Yes innodb_thread_concurrencyYes Yes Yes Global Yes innodb_thread_sleep_delayYes Yes Yes Global Yes innodb_use_legacy_cardinality_algorithmYes Yes Yes Global Yes innodb_use_sys_mallocYes Yes Yes Global No innodb_version Yes Global No innodb_write_io_threadsYes Yes Yes Global No insert_id Yes Session Yes install Yes install-manual Yes interactive_timeoutYes Yes Yes Both Yes join_buffer_sizeYes Yes Yes Both Yes keep_files_on_createYes Yes Yes Both Yes Key_blocks_not_flushed Yes Global No Key_blocks_unused Yes Global No Key_blocks_used Yes Global No key_buffer_sizeYes Yes Yes Global Yes key_cache_age_thresholdYes Yes Yes Global Yes key_cache_block_sizeYes Yes Yes Global Yes key_cache_division_limitYes Yes Yes Global Yes Key_read_requests Yes Global No Key_reads Yes Global No Key_write_requests Yes Global No Key_writes Yes Global No language Yes Yes Yes Global No large_files_support Yes Global No large_page_size Yes Global No large-pages Yes Yes Global No - _Variable_: Yes Global No large_pages last_insert_id Yes Session Yes Last_query_cost Yes Session No lc_time_names Yes Both Yes license Yes Global No local_infile Yes Global Yes local-infile Yes Yes - _Variable_: local_infile locked_in_memory Yes Global No log Yes Yes Yes Global Yes log_bin Yes Global No log-bin Yes Yes Yes Global No log-bin-index Yes Yes log-bin-trust-function-creatorsYes Yes Global Yes - _Variable_: Yes Global Yes log_bin_trust_function_creators log-bin-trust-routine-creatorsYes Yes Global Yes - _Variable_: Yes Global Yes log_bin_trust_routine_creators log-error Yes Yes Global No - _Variable_: Yes Global No log_error log-isam Yes Yes log-output Yes Yes Global Yes - _Variable_: Yes Global Yes log_output log-queries-not-using-indexesYes Yes Global Yes - _Variable_: Yes Global Yes log_queries_not_using_indexes log-short-formatYes Yes log-slave-updatesYes Yes Global No - _Variable_: Yes Global No log_slave_updates log-slow-admin-statementsYes Yes log-slow-queriesYes Yes Global Yes - _Variable_: Yes Global Yes log_slow_queries log-slow-slave-statementsYes Yes log-tc Yes Yes log-tc-size Yes Yes log-warnings Yes Yes Both Yes - _Variable_: Yes Both Yes log_warnings long_query_timeYes Yes Yes Both Yes low-priority-updatesYes Yes Both Yes - _Variable_: Yes Both Yes low_priority_updates lower_case_file_systemYes Yes Yes Global No lower_case_table_namesYes Yes Yes Global No master-connect-retryYes Yes master-host Yes Yes master-info-fileYes Yes master-passwordYes Yes master-port Yes Yes master-retry-countYes Yes master-ssl Yes Yes master-ssl-ca Yes Yes master-ssl-capathYes Yes master-ssl-certYes Yes master-ssl-cipherYes Yes master-ssl-key Yes Yes master-user Yes Yes max_allowed_packetYes Yes Yes Global Yes max_binlog_cache_sizeYes Yes Yes Global Yes max-binlog-dump-eventsYes Yes max_binlog_sizeYes Yes Yes Global Yes max_connect_errorsYes Yes Yes Global Yes max_connectionsYes Yes Yes Global Yes max_delayed_threadsYes Yes Yes Both Yes max_error_countYes Yes Yes Both Yes max_heap_table_sizeYes Yes Yes Both Yes max_insert_delayed_threads Yes Both Yes max_join_size Yes Yes Yes Both Yes max_length_for_sort_dataYes Yes Yes Both Yes max_long_data_sizeYes Yes Yes Global No max_prepared_stmt_countYes Yes Yes Global Yes max_relay_log_sizeYes Yes Yes Global Yes max_seeks_for_keyYes Yes Yes Both Yes max_sort_lengthYes Yes Yes Both Yes max_sp_recursion_depthYes Yes Yes Both Yes max_tmp_tables Yes Yes Yes Both Yes Max_used_connections Yes Global No max_user_connectionsYes Yes Yes Both Yes max_write_lock_countYes Yes Yes Global Yes memlock Yes Yes Yes Global No merge Yes Yes min-examined-row-limitYes Yes Yes Both Yes multi_range_countYes Yes Yes Both Yes myisam-block-sizeYes Yes myisam_data_pointer_sizeYes Yes Yes Global Yes myisam_max_sort_file_sizeYes Yes Yes Global Yes myisam_mmap_sizeYes Yes Yes Global No myisam-recover Yes Yes - _Variable_: myisam_recover_options myisam_recover_options Yes Global No myisam_repair_threadsYes Yes Yes Both Yes myisam_sort_buffer_sizeYes Yes Yes Both Yes myisam_stats_methodYes Yes Yes Both Yes myisam_use_mmapYes Yes Yes Global Yes named_pipe Yes Global No ndb_autoincrement_prefetch_szYes Yes Yes Both Yes ndb-batch-size Yes Yes Yes Global No ndb-blob-read-batch-bytesYes Yes Yes Both Yes ndb-blob-write-batch-bytesYes Yes Yes Both Yes ndb_cache_check_timeYes Yes Yes Global Yes ndb-cluster-connection-poolYes Yes Yes Yes Global No Ndb_cluster_node_id Yes Both No Ndb_config_from_host Yes Both No Ndb_config_from_port Yes Both No Ndb_conflict_fn_max Yes Global No Ndb_conflict_fn_old Yes Global No ndb-connectstringYes Yes ndb_execute_count Yes Global No ndb_extra_loggingYes Yes Yes Global Yes ndb_force_send Yes Yes Yes Both Yes ndb_index_stat_cache_entriesYes Yes ndb_index_stat_enableYes Yes ndb_index_stat_update_freqYes Yes ndb_join_pushdown Yes Global No ndb-log-apply-statusYes Yes Global No - _Variable_: Yes Global No ndb_log_apply_status ndb_log_bin Yes Yes Both Yes ndb_log_binlog_indexYes Yes Global Yes ndb_log_empty_epochsYes Yes Yes Global Yes *Note Yes Global No ndb_log_orig: mysql-cluster-replication-schema. ndb-log-update-as-writeYes Yes Yes Global Yes ndb_log_updated_onlyYes Yes Yes Global Yes ndb-mgmd-host Yes Yes ndb-nodeid Yes Yes Yes Global No Ndb_number_of_data_nodes Yes Global No ndb_optimization_delay Yes Global Yes ndb_optimized_node_selectionYes Yes ndb_pruned_scan_count Yes Global No ndb_pushed_queries_defined Yes Global No ndb_pushed_queries_dropped Yes Global No ndb_pushed_queries_executed Yes Global No ndb_pushed_reads Yes Global No ndb_report_thresh_binlog_epoch_slipYes Yes ndb_report_thresh_binlog_mem_usageYes Yes ndb_scan_count Yes Global No ndb_table_no_logging Yes Session Yes ndb_table_temporary Yes Session Yes ndb_use_copying_alter_table Yes Both No ndb_use_exact_count Yes Both Yes ndb_use_transactionsYes Yes Yes Both Yes ndb-wait-connectedYes Yes Yes Global No ndb-wait-setup Yes Yes Yes Global No ndbcluster Yes Yes - _Variable_: have_ndbcluster ndbinfo_database Yes Global No ndbinfo_max_bytesYes Yes Both Yes ndbinfo_max_rowsYes Yes Both Yes ndbinfo_show_hiddenYes Yes Both Yes ndbinfo_table_prefixYes Yes Both Yes ndbinfo_version Yes Global No net_buffer_lengthYes Yes Yes Both Yes net_read_timeoutYes Yes Yes Both Yes net_retry_countYes Yes Yes Both Yes net_write_timeoutYes Yes Yes Both Yes new Yes Yes Yes Both Yes no-defaults Yes Not_flushed_delayed_rows Yes Global No old Yes Yes Yes Global No old-alter-tableYes Yes Both Yes - _Variable_: Yes Both Yes old_alter_table old-passwords Yes Yes Both Yes - _Variable_: Yes Both Yes old_passwords old-style-user-limitsYes Yes one-thread Yes Yes Open_files Yes Global No open-files-limitYes Yes Global No - _Variable_: Yes Global No open_files_limit Open_streams Yes Global No Open_table_definitions Yes Global No Open_tables Yes Both No Opened_files Yes Global No Opened_table_definitions Yes Both No Opened_tables Yes Both No optimizer_prune_levelYes Yes Yes Both Yes optimizer_search_depthYes Yes Yes Both Yes optimizer_switchYes Yes Yes Both Yes partition Yes Yes Global No - _Variable_: Yes Global No have_partitioning pid-file Yes Yes Global No - _Variable_: Yes Global No pid_file plugin Yes Yes plugin_dir Yes Yes Yes Global No plugin-load Yes Yes port Yes Yes Yes Global No port-open-timeoutYes Yes preload_buffer_sizeYes Yes Yes Both Yes Prepared_stmt_count Yes Global No prepared_stmt_count Yes Global No print-defaults Yes profiling Yes Session Yes profiling_history_size Yes Both Yes protocol_version Yes Global No pseudo_thread_id Yes Session Yes Qcache_free_blocks Yes Global No Qcache_free_memory Yes Global No Qcache_hits Yes Global No Qcache_inserts Yes Global No Qcache_lowmem_prunes Yes Global No Qcache_not_cached Yes Global No Qcache_queries_in_cache Yes Global No Qcache_total_blocks Yes Global No Queries Yes Both No query_alloc_block_sizeYes Yes Yes Both Yes query_cache_limitYes Yes Yes Global Yes query_cache_min_res_unitYes Yes Yes Global Yes query_cache_sizeYes Yes Yes Global Yes query_cache_typeYes Yes Yes Both Yes query_cache_wlock_invalidateYes Yes Yes Both Yes query_prealloc_sizeYes Yes Yes Both Yes Questions Yes Both No rand_seed1 Yes Session Yes rand_seed2 Yes Session Yes range_alloc_block_sizeYes Yes Yes Both Yes read_buffer_sizeYes Yes Yes Both Yes read_only Yes Yes Yes Global Yes read_rnd_buffer_sizeYes Yes Yes Both Yes relay-log Yes Yes relay-log-indexYes Yes Both No - _Variable_: Yes Both No relay_log_index relay_log_indexYes Yes Yes Global No relay-log-info-fileYes Yes - _Variable_: relay_log_info_file relay_log_info_fileYes Yes Yes Global No relay_log_purgeYes Yes Yes Global Yes relay_log_space_limitYes Yes Yes Global No remove Yes replicate-do-dbYes Yes replicate-do-tableYes Yes replicate-ignore-dbYes Yes replicate-ignore-tableYes Yes replicate-rewrite-dbYes Yes replicate-same-server-idYes Yes replicate-wild-do-tableYes Yes replicate-wild-ignore-tableYes Yes report-host Yes Yes Global No - _Variable_: Yes Global No report_host report-passwordYes Yes Global No - _Variable_: Yes Global No report_password report-port Yes Yes Global No - _Variable_: Yes Global No report_port report-user Yes Yes Global No - _Variable_: Yes Global No report_user rpl_recovery_rank Yes Global Yes Rpl_status Yes Global No safe-mode Yes Yes safe-show-databaseYes Yes Yes Global Yes safe-user-createYes Yes safemalloc-mem-limitYes Yes secure-auth Yes Yes Global Yes - _Variable_: Yes Global Yes secure_auth secure-file-privYes Yes Global No - _Variable_: Yes Global No secure_file_priv Select_full_join Yes Both No Select_full_range_join Yes Both No Select_range Yes Both No Select_range_check Yes Both No Select_scan Yes Both No server-id Yes Yes Global Yes - _Variable_: Yes Global Yes server_id server-id-bits Yes Yes Global No - _Variable_: Yes Global No server_id_bits shared_memory Yes Global No shared_memory_base_name Yes Global No show-slave-auth-infoYes Yes skip-character-set-client-handshakeYes Yes skip-concurrent-insertYes Yes - _Variable_: concurrent_insert skip-event-schedulerYes Yes skip-external-lockingYes Yes Global No - _Variable_: Yes Global No skip_external_locking skip-grant-tablesYes Yes skip-host-cacheYes Yes skip-locking Yes Yes skip-log-warningsYes skip-merge Yes Yes - _Variable_: skip-name-resolveYes Yes Global No - _Variable_: Yes Global No skip_name_resolve skip-ndbclusterYes Yes skip-networkingYes Yes Global No - _Variable_: Yes Global No skip_networking skip-new Yes Yes skip-partition Yes Yes skip-safemallocYes Yes skip-show-databaseYes Yes Global No - _Variable_: Yes Global No skip_show_database skip-slave-startYes Yes skip-ssl Yes Yes skip-stack-traceYes Yes skip-symbolic-linksYes skip-symlink Yes Yes skip-thread-priorityYes Yes slave_allow_batchingYes Yes Yes Global Yes slave_compressed_protocolYes Yes Yes Global Yes slave_exec_mode Yes Global Yes Slave_heartbeat_period Yes Global No slave-load-tmpdirYes Yes Global No - _Variable_: Yes Global No slave_load_tmpdir slave-net-timeoutYes Yes Global Yes - _Variable_: Yes Global Yes slave_net_timeout Slave_open_temp_tables Yes Global No Slave_received_heartbeats Yes Global No Slave_retried_transactions Yes Global No Slave_running Yes Global No slave-skip-errorsYes Yes Global No - _Variable_: Yes Global No slave_skip_errors slave_transaction_retriesYes Yes Yes Global Yes slave_type_conversionsYes Yes Yes Global No Slow_launch_threads Yes Both No slow_launch_timeYes Yes Yes Global Yes Slow_queries Yes Both No slow-query-log Yes Yes Global Yes - _Variable_: Yes Global Yes slow_query_log slow_query_log_fileYes Yes Yes Global Yes socket Yes Yes Yes Global No sort_buffer_sizeYes Yes Yes Both Yes Sort_merge_passes Yes Both No Sort_range Yes Both No Sort_rows Yes Both No Sort_scan Yes Both No sporadic-binlog-dump-failYes Yes sql_auto_is_null Yes Session Yes sql_big_selects Yes Session Yes sql_big_tables Yes Session Yes sql_buffer_result Yes Session Yes sql_log_bin Yes Session Yes sql_log_off Yes Session Yes sql_log_update Yes Session Yes sql_low_priority_updates Yes Both Yes sql_max_join_size Yes Both Yes sql-mode Yes Yes Both Yes - _Variable_: Yes Both Yes sql_mode sql_notes Yes Session Yes sql_quote_show_create Yes Session Yes sql_safe_updates Yes Session Yes sql_select_limit Yes Both Yes sql_slave_skip_counter Yes Global Yes sql_warnings Yes Session Yes ssl Yes Yes Ssl_accept_renegotiates Yes Global No Ssl_accepts Yes Global No ssl-ca Yes Yes Global No - _Variable_: Yes Global No ssl_ca Ssl_callback_cache_hits Yes Global No ssl-capath Yes Yes Global No - _Variable_: Yes Global No ssl_capath ssl-cert Yes Yes Global No - _Variable_: Yes Global No ssl_cert ssl-cipher Yes Yes Global No - _Variable_: Yes Global No ssl_cipher Ssl_cipher Yes Both No Ssl_cipher_list Yes Both No Ssl_client_connects Yes Global No Ssl_connect_renegotiates Yes Global No Ssl_ctx_verify_depth Yes Global No Ssl_ctx_verify_mode Yes Global No Ssl_default_timeout Yes Both No Ssl_finished_accepts Yes Global No Ssl_finished_connects Yes Global No ssl-key Yes Yes Global No - _Variable_: Yes Global No ssl_key Ssl_session_cache_hits Yes Global No Ssl_session_cache_misses Yes Global No Ssl_session_cache_mode Yes Global No Ssl_session_cache_overflows Yes Global No Ssl_session_cache_size Yes Global No Ssl_session_cache_timeouts Yes Global No Ssl_sessions_reused Yes Both No Ssl_used_session_cache_entries Yes Global No Ssl_verify_depth Yes Both No Ssl_verify_mode Yes Both No ssl-verify-server-certYes Yes Ssl_version Yes Both No standalone Yes Yes storage_engine Yes Both Yes symbolic-links Yes Yes sync_binlog Yes Yes Yes Global Yes sync_frm Yes Yes Yes Global Yes sysdate-is-now Yes Yes system_time_zone Yes Global No table_cache Yes Yes Yes Global Yes table_definition_cacheYes Yes Yes Global Yes table_lock_wait_timeoutYes Yes Yes Global Yes Table_locks_immediate Yes Global No Table_locks_waited Yes Global No table_open_cacheYes Yes Yes Global Yes table_type Yes Both Yes tc-heuristic-recoverYes Yes Tc_log_max_pages_used Yes Global No Tc_log_page_size Yes Global No Tc_log_page_waits Yes Global No temp-pool Yes Yes thread_cache_sizeYes Yes Yes Global Yes thread_concurrencyYes Yes Yes Global No thread_handlingYes Yes Yes Global No thread_stack Yes Yes Yes Global No Threads_cached Yes Global No Threads_connected Yes Global No Threads_created Yes Global No Threads_running Yes Global No time_format Yes Both No time_zone Yes Yes Yes Both Yes timed_mutexes Yes Yes Yes Global Yes timestamp Yes Session Yes tmp_table_size Yes Yes Yes Both Yes tmpdir Yes Yes Yes Global No transaction_alloc_block_sizeYes Yes Yes Both Yes transaction_allow_batching Yes Session Yes transaction-isolationYes Yes - _Variable_: tx_isolation transaction_prealloc_sizeYes Yes Yes Both Yes tx_isolation Yes Both Yes unique_checks Yes Session Yes updatable_views_with_limitYes Yes Yes Both Yes Uptime Yes Global No Uptime_since_flush_status Yes Global No use-symbolic-linksYes Yes user Yes Yes verbose Yes Yes version Yes Global No version_comment Yes Global No version_compile_machine Yes Global No version_compile_os Yes Global No wait_timeout Yes Yes Yes Both Yes warning_count Yes Session No  File: manual.info, Node: server-options, Next: server-system-variables, Prev: mysqld-option-tables, Up: mysqld-server 6.1.2 Server Command Options ---------------------------- When you start the *Note `mysqld': mysqld. server, you can specify program options using any of the methods described in *Note program-options::. The most common methods are to provide options in an option file or on the command line. However, in most cases it is desirable to make sure that the server uses the same options each time it runs. The best way to ensure this is to list them in an option file. See *Note option-files::. *Note `mysqld': mysqld. reads options from the `[mysqld]' and `[server]' groups. *Note `mysqld_safe': mysqld-safe. reads options from the `[mysqld]', `[server]', `[mysqld_safe]', and `[safe_mysqld]' groups. *Note `mysql.server': mysql-server. reads options from the `[mysqld]' and `[mysql.server]' groups. An embedded MySQL server usually reads options from the `[server]', `[embedded]', and `[XXXXX_SERVER]' groups, where XXXXX is the name of the application into which the server is embedded. *Note `mysqld': mysqld. accepts many command options. For a brief summary, execute *Note `mysqld --help': mysqld. To see the full list, use *Note `mysqld --verbose --help': mysqld. The following list shows some of the most common server options. Additional options are described in other sections: * Options that affect security: See *Note privileges-options::. * SSL-related options: See *Note ssl-options::. * Binary log control options: See *Note binary-log::. * Replication-related options: See *Note replication-options::. * Options for loading plugins such as pluggable storage engines: See *Note server-plugin-loading::. * Options specific to particular storage engines: See *Note myisam-start::, *Note innodb-parameters::, and *Note mysql-cluster-program-options-mysqld::. You can also set the values of server system variables by using variable names as options, as described at the end of this section. Some options control the size of buffers or caches. For a given buffer, the server might need to allocate internal data structures. These structures typically are allocated from the total memory allocated to the buffer, and the amount of space required might be platform dependent. This means that when you assign a value to an option that controls a buffer size, the amount of space actually available might differ from the value assigned. In some cases, the amount might be less than the value assigned. It is also possible that the server will adjust a value upward. For example, if you assign a value of 0 to an option for which the minimal value is 1024, the server will set the value to 1024. Values for buffer sizes, lengths, and stack sizes are given in bytes unless otherwise specified. Some options take file name values. Unless otherwise specified, the default file location is the data directory if the value is a relative path name. To specify the location explicitly, use an absolute path name. Suppose that the data directory is `/var/mysql/data'. If a file-valued option is given as a relative path name, it will be located under `/var/mysql/data'. If the value is an absolute path name, its location is as given by the path name. * `--help', `-?' Options for help *Command-Line `-?' Format* ** `--help' *Option-File Format* `help' Display a short help message and exit. Use both the `--verbose' and `--help' options to see the full message. * `--allow-suspicious-udfs' Options for allow-suspicious-udfs *Command-Line `--allow-suspicious-udfs' Format* *Option-File Format* `allow-suspicious-udfs' *Permitted Values * *Type* `boolean' *Default* `FALSE' This option controls whether user-defined functions that have only an `xxx' symbol for the main function can be loaded. By default, the option is off and only UDFs that have at least one auxiliary symbol can be loaded; this prevents attempts at loading functions from shared object files other than those containing legitimate UDFs. See *Note udf-security::. * `--ansi' Options for ansi *Command-Line `--ansi' Format* ** `-a' *Option-File Format* `ansi' Use standard (ANSI) SQL syntax instead of MySQL syntax. For more precise control over the server SQL mode, use the `--sql-mode' option instead. See *Note ansi-mode::, and *Note server-sql-mode::. * `--basedir=PATH', `-b PATH' Options for basedir *Command-Line `--basedir=path' Format* ** `-b' *Option-File Format* `basedir' *Option Sets Yes, Variable* `basedir' *Variable Name* `basedir' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `file name' The path to the MySQL installation directory. All paths are usually resolved relative to this directory. * `--big-tables' Options for big-tables *Command-Line `--big-tables' Format* *Option-File Format* `big-tables' *Option Sets Yes, Variable* `big_tables' *Variable Name* `big-tables' *Variable Scope* Session *Dynamic Variable* Yes *Permitted Values * *Type* `boolean' Enable large result sets by saving all temporary sets in files. This option prevents most `table full' errors, but also slows down queries for which in-memory tables would suffice. Since MySQL 3.23.2, the server is able to handle large result sets automatically by using memory for small temporary tables and switching to disk tables where necessary. * `--bind-address=IP' Options for bind-address *Command-Line `--bind-address=name' Format* *Option-File Format* `bind-address=name' *Variable Name* `bind-address' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `string' *Default* `0.0.0.0' *Range* `0.0.0.0-255.255.255.255' The IP address to bind to. Only one address can be selected. If this option is specified multiple times, the last address given is used. If no address or `0.0.0.0' is specified, the server listens on all interfaces. * `--binlog-format={ROW|STATEMENT|MIXED}' Options for binlog-format *Version Introduced* 5.1.5 *Command-Line `--binlog-format=format' Format* *Option-File Format* `binlog-format=format' *Option Sets Yes, Variable* `binlog_format' *Variable Name* `binlog_format' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values (>= 5.1.5, <= 5.1.7)* *Type* `enumeration' *Default* `STATEMENT' *Valid Values* `ROW' `STATEMENT' *Permitted Values (>= 5.1.8, <= 5.1.11)* *Type* `enumeration' *Default* `STATEMENT' *Valid Values* `ROW' `STATEMENT' `MIXED' *Permitted Values (>= 5.1.12, <= 5.1.28)* *Type* `enumeration' *Default* `MIXED' *Valid Values* `ROW' `STATEMENT' `MIXED' *Permitted Values (>= 5.1.29)* *Type* `enumeration' *Default* `STATEMENT' *Valid Values* `ROW' `STATEMENT' `MIXED' Specify whether to use row-based, statement-based, or mixed replication (statement-based was the default prior to MySQL 5.1.12; in 5.1.12, the default was changed to mixed replication; in 5.1.29, the default was changed back to statement-based). See *Note replication-formats::. This option was added in MySQL 5.1.5. *Important*: Setting the binary logging format without enabling binary logging prevents the MySQL server from starting. This is a known issue in MySQL 5.1 which is fixed in MySQL 5.5. (Bug#42928) MySQL Cluster The default value for this option in all MySQL Cluster NDB 6.1, 6.2, 6.3, and later 6.x releases is `MIXED'. See *Note mysql-cluster-replication-general::, for more information. * `--bootstrap' Options for bootstrap *Command-Line `--bootstrap' Format* *Option-File Format* `bootstrap' This option is used by the *Note `mysql_install_db': mysql-install-db. script to create the MySQL privilege tables without having to start a full MySQL server. This option is unavailable if MySQL was configured with the `--disable-grant-options' option. See *Note source-configuration-options::. * `--character-sets-dir=PATH' Options for character-sets-dir *Command-Line `--character-sets-dir=path' Format* *Option-File Format* `character-sets-dir=path' *Option Sets Yes, Variable* `character_sets_dir' *Variable Name* `character-sets-dir' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `directory name' The directory where character sets are installed. See *Note charset-configuration::. * `--character-set-client-handshake' Options for character-set-client-handshake *Command-Line `--character-set-client-handshake' Format* *Option-File Format* `character-set-client-handshake' *Permitted Values * *Type* `boolean' *Default* `TRUE' Do not ignore character set information sent by the client. To ignore client information and use the default server character set, use `--skip-character-set-client-handshake'; this makes MySQL behave like MySQL 4.0. * `--character-set-filesystem=CHARSET_NAME' Options for character-set-filesystem *Version Introduced* 5.1.6 *Command-Line `--character-set-filesystem=name' Format* *Option-File Format* `character-set-filesystem' *Option Sets Yes, Variable* `character_set_filesystem' *Variable Name* `character_set_filesystem' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `string' The file system character set. This option sets the `character_set_filesystem' system variable. It was added in MySQL 5.1.6. * `--character-set-server=CHARSET_NAME', `-C CHARSET_NAME' Options for character-set-server *Command-Line `--character-set-server' Format* *Option-File Format* `character-set-server' *Option Sets Yes, Variable* `character_set_server' *Variable Name* `character_set_server' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `string' Use CHARSET_NAME as the default server character set. See *Note charset-configuration::. If you use this option to specify a nondefault character set, you should also use `--collation-server' to specify the collation. * `--chroot=PATH', `-r PATH' Options for chroot *Command-Line `--chroot=name' Format* ** `-r name' *Option-File Format* `chroot' *Permitted Values * *Type* `file name' Put the *Note `mysqld': mysqld. server in a closed environment during startup by using the `chroot()' system call. This is a recommended security measure. Note that use of this option somewhat limits *Note `LOAD DATA INFILE': load-data. and *Note `SELECT ... INTO OUTFILE': select. * `--collation-server=COLLATION_NAME' Options for collation-server *Command-Line `--collation-server' Format* *Option-File Format* `collation-server' *Option Sets Yes, Variable* `collation_server' *Variable Name* `collation_server' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `string' Use COLLATION_NAME as the default server collation. See *Note charset-configuration::. * `--console' Options for console *Command-Line `--console' Format* *Option-File Format* `console' *Platform Specific* windows (Windows only.) Write error log messages to `stderr' and `stdout' even if `--log-error' is specified. *Note `mysqld': mysqld. does not close the console window if this option is used. * `--core-file' Options for core-file *Command-Line `--core-file' Format* *Option-File Format* `core-file' *Permitted Values * *Type* `boolean' *Default* `FALSE' Write a core file if *Note `mysqld': mysqld. dies. The name and location of the core file is system dependent. On Linux, a core file named `core.PID' is written to the current working directory of the process, which for *Note `mysqld': mysqld. is the data directory. PID represents the process ID of the server process. On Mac OS X, a core file named `core.PID' is written to the `/cores' directory. On Solaris, use the `coreadm' command to specify where to write the core file and how to name it. For some systems, to get a core file you must also specify the `--core-file-size' option to *Note `mysqld_safe': mysqld-safe. See *Note mysqld-safe::. On some systems, such as Solaris, you do not get a core file if you are also using the `--user' option. There might be additional restrictions or limitations. For example, it might be necessary to execute `ulimit -c unlimited' before starting the server. Consult your system documentation. * `--datadir=PATH', `-h PATH' Options for datadir *Command-Line `--datadir=path' Format* ** `-h' *Option-File Format* `datadir' *Option Sets Yes, Variable* `datadir' *Variable Name* `datadir' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `file name' The path to the data directory. * `--debug[=DEBUG_OPTIONS]', `-# [DEBUG_OPTIONS]' Options for debug *Command-Line `--debug[=debug_options]' Format* *Option-File Format* `debug' *Variable Name* `debug' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `string' *Default* `'d:t:o,/tmp/mysqld.trace'' If MySQL is configured with `--with-debug', you can use this option to get a trace file of what *Note `mysqld': mysqld. is doing. A typical DEBUG_OPTIONS string is `'d:t:o,FILE_NAME''. The default is `'d:t:i:o,mysqld.trace''. See MySQL Internals: Porting (http://forge.mysql.com/wiki/MySQL_Internals_Porting). As of MySQL 5.1.12, using `--with-debug' to configure MySQL with debugging support enables you to use the `--debug="d,parser_debug"' option when you start the server. This causes the Bison parser that is used to process SQL statements to dump a parser trace to the server's standard error output. Typically, this output is written to the error log. This option may be given multiple times. Values that begin with `+' or `-' are added to or subtracted from the previous value. For example, `--debug=T' `--debug=+P' sets the value to `P:T'. * `--debug-sync-timeout[=N]' Options for debug-sync-timeout *Version Introduced* 5.1.41 *Command-Line `--debug-sync-timeout[=#]' Format* *Option-File Format* `debug-sync-timeout' *Permitted Values * *Type* `numeric' Controls whether the Debug Sync facility for testing and debugging is enabled. Use of Debug Sync requires that MySQL be configured with the `--enable-debug-sync' option (see *Note source-configuration-options::). If Debug Sync is not compiled in, this option is not available. The option value is a timeout in seconds. The default value is 0, which disables Debug Sync. To enable it, specify a value greater than 0; this value also becomes the default timeout for individual synchronization points. If the option is given without a value, the timeout is set to 300 seconds. For a description of the Debug Sync facility and how to use synchronization points, see MySQL Internals: Test Synchronization (http://forge.mysql.com/wiki/MySQL_Internals_Test_Synchronization). This option was added in MySQL 5.1.41. * `--default-character-set=CHARSET_NAME' Options for default-character-set *Command-Line `--default-character-set=name' Format* ** `-C name' *Option-File Format* `default-character-set=name' *Deprecated* 5.0 *Permitted Values * *Type* `string' Use CHARSET_NAME as the default character set. This option is deprecated in favor of `--character-set-server'. See *Note charset-configuration::. `--default-character-set' is removed in MySQL 5.5. * `--default-collation=COLLATION_NAME' Options for default-collation *Command-Line `--default-collation=name' Format* *Option-File Format* `default-collation=name' *Deprecated* 4.1.3 *Permitted Values * *Type* `string' Use COLLATION_NAME as the default collation. This option is deprecated in favor of `--collation-server'. See *Note charset-configuration::. `--default-collation' is removed in MySQL 5.5. * `--default-storage-engine=TYPE' Options for default-storage-engine *Command-Line `--default-storage-engine=name' Format* *Option-File Format* `default-storage-engine' *Variable Name* `default-storage-engine' *Variable Scope* Global, Session *Dynamic Variable* Yes Set the default storage engine (table type) for tables. See *Note storage-engines::. * `--default-table-type=TYPE' Options for default-table-type *Command-Line `--default-table-type=name' Format* *Option-File Format* `default-table-type' *Deprecated* 5.0, by `default-storage-engine' *Permitted Values * *Type* `string' This option is a synonym for `--default-storage-engine'. It is deprecated and removed in MySQL 5.5. * `--default-time-zone=TIMEZONE' Options for default-time-zone *Command-Line `--default-time-zone=name' Format* *Option-File Format* `default-time-zone' *Permitted Values * *Type* `string' Set the default server time zone. This option sets the global `time_zone' system variable. If this option is not given, the default time zone is the same as the system time zone (given by the value of the `system_time_zone' system variable. * `--delay-key-write[={OFF|ON|ALL}]' Options for delay-key-write *Command-Line `--delay-key-write[=name]' Format* *Option-File Format* `delay-key-write' *Option Sets Yes, Variable* `delay_key_write' *Variable Name* `delay-key-write' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `enumeration' *Default* `ON' *Valid Values* `ON' `OFF' `ALL' Specify how to use delayed key writes. Delayed key writing causes key buffers not to be flushed between writes for `MyISAM' tables. `OFF' disables delayed key writes. `ON' enables delayed key writes for those tables that were created with the `DELAY_KEY_WRITE' option. `ALL' delays key writes for all `MyISAM' tables. See *Note server-parameters::, and *Note myisam-start::. *Note*: If you set this variable to `ALL', you should not use `MyISAM' tables from within another program (such as another MySQL server or *Note `myisamchk': myisamchk.) when the tables are in use. Doing so leads to index corruption. * `--des-key-file=FILE_NAME' Options for des-key-file *Command-Line `--des-key-file=file_name' Format* *Option-File Format* `des-key-file=file_name' Read the default DES keys from this file. These keys are used by the `DES_ENCRYPT()' and `DES_DECRYPT()' functions. * `--enable-named-pipe' Options for enable-named-pipe *Command-Line `--enable-named-pipe' Format* *Option-File Format* `enable-named-pipe' *Option Sets Yes, Variable* `named_pipe' *Platform Specific* windows Enable support for named pipes. This option applies only on Windows. For MySQL 5.1.20 and earlier, this option is available only when using the *Note `mysqld-nt': mysqld. and `mysqld-debug' servers that support named-pipe connections. For MySQL 5.1.21 and later, *Note `mysqld-nt': mysqld. is not available, but support is included in the standard *Note `mysqld': mysqld. and *Note `mysqld-debug': mysqld. servers. * `--enable-pstack' Options for enable-pstack *Version Deprecated* 5.1.54 *Command-Line `--enable-pstack' Format* *Option-File Format* `enable-pstack' *Deprecated* 5.1.54 *Permitted Values * *Type* `boolean' *Default* `FALSE' This option is nonfunctional. It is deprecated as of MySQL 5.1.54 and removed in MySQL 5.5. * `--engine-condition-pushdown={ON|OFF}' Options for engine-condition-pushdown *Command-Line `--engine-condition-pushdown' Format* *Option-File Format* `engine-condition-pushdown' *Option Sets Yes, Variable* `engine_condition_pushdown' *Variable Name* `engine_condition_pushdown' *Variable Scope* Global, Session *Dynamic Variable* Yes *Deprecated* 5.5.3, by `optimizer_switch' *Permitted Values (>= 5.1.0)* *Type* `boolean' *Default* `ON' Sets the `engine_condition_pushdown' system variable. For more information, see *Note condition-pushdown-optimization::. * `--event-scheduler[=VALUE]' Options for event-scheduler *Version Introduced* 5.1.6 *Command-Line `--event-scheduler[=value]' Format* *Option-File Format* `event-scheduler' *Option Sets Yes, Variable* `event_scheduler' *Variable Name* `event_scheduler' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `enumeration' *Default* `OFF' *Valid Values* `ON' `OFF' `DISABLED' Enable or disable, and start or stop, the event scheduler. This option was added in MySQL 5.1.6. Note that its permitted values and behavior changed in MySQL 5.1.11, and again in MySQL 5.1.12. For detailed information, see The `--event-scheduler' Option. * `--exit-info[=FLAGS]', `-T [FLAGS]' Options for exit-info *Command-Line `--exit-info[=flags]' Format* ** `-T [flags]' *Option-File Format* `exit-info' *Permitted Values * *Type* `numeric' This is a bit mask of different flags that you can use for debugging the *Note `mysqld': mysqld. server. Do not use this option unless you know _exactly_ what it does! * `--external-locking' Options for external-locking *Command-Line `--external-locking' Format* *Option-File Format* `external-locking' *Option Sets Yes, Variable* `skip_external_locking' *Disabled by* `skip-external-locking' *Permitted Values * *Type* `boolean' *Default* `FALSE' Enable external locking (system locking), which is disabled by default as of MySQL 4.0. Note that if you use this option on a system on which `lockd' does not fully work (such as Linux), it is easy for *Note `mysqld': mysqld. to deadlock. External locking affects only *Note `MyISAM': myisam-storage-engine. table access. For more information, including conditions under which it can and cannot be used, see *Note external-locking::. * `--flush' Options for flush *Command-Line `--flush' Format* *Option-File Format* `flush' *Variable Name* `flush' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `boolean' *Default* `OFF' Flush (synchronize) all changes to disk after each SQL statement. Normally, MySQL does a write of all changes to disk only after each SQL statement and lets the operating system handle the synchronizing to disk. See *Note crashing::. * `--gdb' Options for gdb *Command-Line `--gdb' Format* *Option-File Format* `gdb' *Permitted Values * *Type* `boolean' *Default* `FALSE' Install an interrupt handler for `SIGINT' (needed to stop *Note `mysqld': mysqld. with `^C' to set breakpoints) and disable stack tracing and core file handling. See MySQL Internals: Porting (http://forge.mysql.com/wiki/MySQL_Internals_Porting). * `--general-log[={0|1}]' Options for general-log *Version Introduced* 5.1.12 *Command-Line `--general-log' Format* *Option-File Format* `general-log' *Option Sets Yes, Variable* `general_log' *Variable Name* `general_log' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `boolean' *Default* `OFF' Specify the initial general query log state. With no argument or an argument of 1, the `--general-log' option enables the log. If omitted or given with an argument of 0, the option disables the log. This option was added in MySQL 5.1.12. * `--init-file=FILE_NAME' Options for init-file *Command-Line `--init-file=file_name' Format* *Option-File Format* `init-file=file_name' *Option Sets Yes, Variable* `init_file' *Variable Name* `init_file' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `file name' Read SQL statements from this file at startup. Each statement must be on a single line and should not include comments. This option is unavailable if MySQL was configured with the `--disable-grant-options' option. See *Note source-configuration-options::. * `--innodb-XXX' The `InnoDB' options are listed in *Note innodb-parameters::. * `--install [SERVICE_NAME]' Options for install *Command-Line `--install Format* [service_name]' (Windows only) Install the server as a Windows service that starts automatically during Windows startup. The default service name is `MySQL' if no SERVICE_NAME value is given. For more information, see *Note windows-start-service::. * `--install-manual [SERVICE_NAME]' Options for install-manual *Command-Line `--install-manual Format* [service_name]' (Windows only) Install the server as a Windows service that must be started manually. It does not start automatically during Windows startup. The default service name is `MySQL' if no SERVICE_NAME value is given. For more information, see *Note windows-start-service::. * `--language=LANG_NAME, -L LANG_NAME' Options for language *Command-Line `--language=name' Format* ** `-L' *Option-File Format* `language' *Option Sets Yes, Variable* `language' *Variable Name* `language' *Variable Scope* Global *Dynamic Variable* No *Deprecated* 5.5.0, by `lc-messages-dir' *Permitted Values * *Type* `directory name' *Default* `/usr/local/mysql/share/mysql/english/' The language to use for error messages. LANG_NAME can be given as the language name or as the full path name to the directory where the language files are installed. See *Note error-message-language::. * `--large-pages' Options for large-pages *Command-Line `--large-pages' Format* *Option-File Format* `large-pages' *Option Sets Yes, Variable* `large_pages' *Variable Name* `large_pages' *Variable Scope* Global *Dynamic Variable* No *Platform Specific* linux *Permitted Values * *Type* (linux) `boolean' *Default* `FALSE' Some hardware/operating system architectures support memory pages greater than the default (usually 4KB). The actual implementation of this support depends on the underlying hardware and operating system. Applications that perform a lot of memory accesses may obtain performance improvements by using large pages due to reduced Translation Lookaside Buffer (TLB) misses. Currently, MySQL supports only the Linux implementation of large page support (which is called HugeTLB in Linux). See *Note large-page-support::. `--large-pages' is disabled by default. * `--log[=FILE_NAME]', `-l [FILE_NAME]' Options for log *Version Deprecated* 5.1.29 *Command-Line `--log[=name]' Format* ** `-l' *Option-File Format* `log' *Option Sets Yes, Variable* `log' *Variable Name* `log' *Variable Scope* Global *Dynamic Variable* Yes *Deprecated* 5.1.29, by `general-log' *Permitted Values * *Type* `string' *Default* `OFF' This option enables logging to the general query log, which contains entries that record client connections and SQL statements received from clients. The log output destination can be selected with the `--log-output' option as of MySQL 5.1.6. Before 5.1.6, logging occurs to the general query log file. If you omit the file name, MySQL uses `HOST_NAME.log' as the file name. See *Note log-destinations::, and *Note query-log::. As of MySQL 5.1.29, the `--log' option is deprecated and is removed (along with the `log' system variable) in MySQL 5.6. Instead, use the `--general_log' option to enable the general query log and the `--general_log_file=FILE_NAME' option to set the general query log file name. * `--log-error[=FILE_NAME]' Options for log-error *Command-Line `--log-error[=name]' Format* *Option-File Format* `log-error' *Option Sets Yes, Variable* `log_error' *Variable Name* `log_error' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `file name' Log errors and startup messages to this file. See *Note error-log::. If you omit the file name, MySQL uses `HOST_NAME.err'. If the file name has no extension, the server adds an extension of `.err'. * `--log-isam[=FILE_NAME]' Options for log-isam *Command-Line `--log-isam[=name]' Format* *Option-File Format* `log-isam' *Permitted Values * *Type* `file name' Log all `MyISAM' changes to this file (used only when debugging `MyISAM'). * `--log-long-format' Options for log-long-format *Command-Line `--log-long-format' Format* ** `-0' *Option-File Format* `log-long-format' *Deprecated* 4.1 Log extra information to the binary log and slow query log, if they have been activated. For example, the user name and timestamp are logged for all queries. This option is deprecated, as it now represents the default logging behavior. (See the description for `--log-short-format'.) The `--log-queries-not-using-indexes' option is available for the purpose of logging queries that do not use indexes to the slow query log. `--log-long-format' is removed in MySQL 5.5. * `--log-output[=VALUE,...]' Options for log-output *Version Introduced* 5.1.6 *Command-Line `--log-output[=name]' Format* *Option-File Format* `log-output' *Option Sets Yes, Variable* `log_output' *Variable Name* `log_output' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `set' *Default* `FILE' *Valid Values* `TABLE' `FILE' `NONE' This option determines the destination for general query log and slow query log output. The option value can be given as one or more of the words `TABLE', `FILE', or `NONE'. If the option is given without a value, the default is `FILE'. (For MySQL 5.1.6 through 5.1.20, the default is `TABLE'.) `TABLE' select logging to the `general_log' and `slow_log' tables in the `mysql' database as a destination. `FILE' selects logging to log files as a destination. `NONE' disables logging. If `NONE' is present in the option value, it takes precedence over any other words that are present. `TABLE' and `FILE' can both be given to select to both log output destinations. This option selects log output destinations, but does not enable log output. To do that, use the `--general_log' and `--slow_query_log' options. For `FILE' logging, the `--general_log_file' and `-slow_query_log_file' options determine the log file location. (Before MySQL 5.1.29, enable the logs with the `--log' and `--log-slow-queries' options. The options take an optional file name argument to specify the log file name.) For more information, see *Note log-destinations::. The `--log-output' option was added in MySQL 5.1.6. * `--log-queries-not-using-indexes' Options for log-queries-not-using-indexes *Command-Line `--log-queries-not-using-indexes' Format* *Option-File Format* `log-queries-not-using-indexes' *Option Sets Yes, Variable* `log_queries_not_using_indexes' *Variable Name* `log_queries_not_using_indexes' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `boolean' If you are using this option with the slow query log enabled, queries that are expected to retrieve all rows are logged. See *Note slow-query-log::. This option does not necessarily mean that no index is used. For example, a query that uses a full index scan uses an index but would be logged because the index would not limit the number of rows. * `--log-short-format' Options for log-short-format *Command-Line `--log-short-format' Format* *Option-File Format* `log-short-format' *Permitted Values * *Type* `boolean' *Default* `FALSE' Originally intended to log less information to the binary log and slow query log, if they have been activated. However, this option is not operational. * `--log-slow-admin-statements' Options for log-slow-admin-statements *Command-Line `--log-slow-admin-statements' Format* *Option-File Format* `log-slow-admin-statements' *Permitted Values * *Type* `boolean' *Default* `FALSE' Log slow administrative statements such as *Note `OPTIMIZE TABLE': optimize-table, *Note `ANALYZE TABLE': analyze-table, and *Note `ALTER TABLE': alter-table. to the slow query log. * `--log-slow-queries[=FILE_NAME]' Options for log-slow-queries *Version Deprecated* 5.1.29 *Command-Line `--log-slow-queries[=name]' Format* *Option-File Format* `log-slow-queries' *Option Sets Yes, Variable* `log_slow_queries' *Variable Name* `log_slow_queries' *Variable Scope* Global *Dynamic Variable* Yes *Deprecated* 5.1.29, by `slow-query-log' *Permitted Values * *Type* `boolean' This option enables logging to the slow query log, which contains entries for all queries that have taken more than `long_query_time' seconds to execute. See the descriptions of the `--log-long-format' and `--log-short-format' options for details. The log output destination can be selected with the `--log-output' option as of MySQL 5.1.6. Before 5.1.6, logging occurs to the slow query log file. If you omit the file name, MySQL uses `HOST_NAME-slow.log' as the file name. See *Note log-destinations::, and *Note slow-query-log::. As of MySQL 5.1.29, the `--log-slow-queries' option is deprecated and is removed (along with the `log_slow_queries' system variable) in MySQL 5.6. Instead, use the `--slow_query_log' option to enable the slow query log and the `--slow_query_log_file=FILE_NAME' option to set the slow query log file name. * `--log-tc=FILE_NAME' Options for log-tc *Command-Line `--log-tc=name' Format* *Option-File Format* `log-tc' *Permitted Values * *Type* `file name' *Default* `tc.log' The name of the memory-mapped transaction coordinator log file (for XA transactions that affect multiple storage engines when the binary log is disabled). The default name is `tc.log'. The file is created under the data directory if not given as a full path name. Currently, this option is unused. * `--log-tc-size=SIZE' Options for log-tc-size *Command-Line `--log-tc-size=#' Format* *Option-File Format* `log-tc-size' *Permitted Values * *Platform Bit Size* `32' *Type* `numeric' *Default* `24576' *Max Value* `4294967295' *Permitted Values * *Platform Bit Size* `64' *Type* `numeric' *Default* `24576' *Max Value* `18446744073709547520' The size in bytes of the memory-mapped transaction coordinator log. The default size is 24KB. * `--log-warnings[=LEVEL]', `-W [LEVEL]' Options for log-warnings *Command-Line `--log-warnings[=#]' Format* ** `-W [#]' *Option-File Format* `log-warnings' *Option Sets Yes, Variable* `log_warnings' *Variable Name* `log_warnings' *Variable Scope* Global, Session *Dynamic Variable* Yes *Disabled by* `skip-log-warnings' *Permitted Values * *Platform Bit Size* `64' *Type* `numeric' *Default* `1' *Range* `0-18446744073709547520' Print out warnings such as `Aborted connection...' to the error log. Enabling this option is recommended, for example, if you use replication (you get more information about what is happening, such as messages about network failures and reconnections). This option is enabled (1) by default, and the default LEVEL value if omitted is 1. To disable this option, use `--log-warnings=0'. If the value is greater than 1, aborted connections are written to the error log. See *Note communication-errors::. If a slave server was started with `--log-warnings' enabled, the slave prints messages to the error log to provide information about its status, such as the binary log and relay log coordinates where it starts its job, when it is switching to another relay log, when it reconnects after a disconnect, and so forth. As of MySQL 5.1.38, the server logs messages about statements that are unsafe for statement-based logging only if `--log-warnings' is enabled. * `--low-priority-updates' Options for low-priority-updates *Command-Line `--low-priority-updates' Format* *Option-File Format* `low-priority-updates' *Option Sets Yes, Variable* `low_priority_updates' *Variable Name* `low_priority_updates' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `boolean' *Default* `FALSE' Give table-modifying operations (*Note `INSERT': insert, *Note `REPLACE': replace, *Note `DELETE': delete, *Note `UPDATE': update.) lower priority than selects. This can also be done using `{INSERT | REPLACE | DELETE | UPDATE} LOW_PRIORITY ...' to lower the priority of only one query, or by `SET LOW_PRIORITY_UPDATES=1' to change the priority in one thread. This affects only storage engines that use only table-level locking (`MyISAM', `MEMORY', `MERGE'). See *Note table-locking::. * `--min-examined-row-limit=NUMBER' Options for min-examined-row-limit *Version Introduced* 5.1.21 *Command-Line `--min-examined-row-limit=#' Format* *Option-File Format* `min-examined-row-limit' *Variable Name* `min_examined_row_limit' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Platform Bit Size* `32' *Type* `numeric' *Default* `0' *Range* `0-4294967295' *Permitted Values * *Platform Bit Size* `64' *Type* `numeric' *Default* `0' *Range* `0-18446744073709547520' When this option is set, queries which examine fewer than NUMBER rows are not written to the slow query log. The default is 0. This option was introduced in MySQL 5.1.21. * `--memlock' Options for memlock *Command-Line `--memlock' Format* *Option-File Format* `memlock' *Variable Name* `locked_in_memory' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `boolean' *Default* `FALSE' Lock the *Note `mysqld': mysqld. process in memory. This option might help if you have a problem where the operating system is causing *Note `mysqld': mysqld. to swap to disk. `--memlock' works on systems that support the `mlockall()' system call; this includes Solaris as well as most Linux distributions that use a 2.4 or newer kernel. On Linux systems, you can tell whether or not `mlockall()' (and thus this option) is supported by checking to see whether or not it is defined in the system `mman.h' file, like this: shell> grep mlockall /usr/include/sys/mman.h If `mlockall()' is supported, you should see in the output of the previous command something like the following: extern int mlockall (int __flags) __THROW; *Important*: Using this option requires that you run the server as `root', which, for reasons of security, is normally not a good idea. See *Note changing-mysql-user::. You must not try to use this option on a system that does not support the `mlockall()' system call; if you do so, *Note `mysqld': mysqld. will very likely crash as soon as you try to start it. * `--myisam-block-size=N' Options for myisam-block-size *Command-Line `--myisam-block-size=#' Format* *Option-File Format* `myisam-block-size' *Permitted Values * *Type* `numeric' *Default* `1024' *Range* `1024-16384' The block size to be used for `MyISAM' index pages. * `--myisam-recover[=OPTION[,OPTION]...]]' Options for myisam-recover *Command-Line `--myisam-recover[=name]' Format* *Option-File Format* `myisam-recover' *Option Sets Yes, Variable* `myisam_recover_options' *Permitted Values * *Type* `enumeration' *Default* `OFF' *Valid Values* `DEFAULT' `BACKUP' `FORCE' `QUICK' Set the `MyISAM' storage engine recovery mode. The option value is any combination of the values of `DEFAULT', `BACKUP', `FORCE', or `QUICK'. If you specify multiple values, separate them by commas. Specifying the option with no argument is the same as specifying `DEFAULT', and specifying with an explicit value of `""' disables recovery (same as not giving the option). If recovery is enabled, each time *Note `mysqld': mysqld. opens a `MyISAM' table, it checks whether the table is marked as crashed or was not closed properly. (The last option works only if you are running with external locking disabled.) If this is the case, *Note `mysqld': mysqld. runs a check on the table. If the table was corrupted, *Note `mysqld': mysqld. attempts to repair it. The following options affect how the repair works. Option Description `DEFAULT' Recovery without backup, forcing, or quick checking. `BACKUP' If the data file was changed during recovery, save a backup of the `TBL_NAME.MYD' file as `TBL_NAME-DATETIME.BAK'. `FORCE' Run recovery even if we would lose more than one row from the `.MYD' file. `QUICK' Do not check the rows in the table if there are not any delete blocks. Before the server automatically repairs a table, it writes a note about the repair to the error log. If you want to be able to recover from most problems without user intervention, you should use the options `BACKUP,FORCE'. This forces a repair of a table even if some rows would be deleted, but it keeps the old data file as a backup so that you can later examine what happened. See *Note myisam-start::. * `--old-alter-table' Options for old-alter-table *Command-Line `--old-alter-table' Format* *Option-File Format* `old-alter-table' *Option Sets Yes, Variable* `old_alter_table' *Variable Name* `old_alter_table' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `boolean' *Default* `OFF' When this option is given, the server does not use the optimized method of processing an *Note `ALTER TABLE': alter-table. operation. It reverts to using a temporary table, copying over the data, and then renaming the temporary table to the original, as used by MySQL 5.0 and earlier. For more information on the operation of *Note `ALTER TABLE': alter-table, see *Note alter-table::. * `--old-passwords' Options for old-passwords *Command-Line `--old_passwords' Format* *Option-File Format* `old-passwords' *Option Sets Yes, Variable* `old_passwords' *Variable Name* `old_passwords' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `boolean' *Default* `FALSE' Force the server to generate short (pre-4.1) password hashes for new passwords. This is useful for compatibility when the server must support older client programs. See *Note password-hashing::. * `--old-style-user-limits' Options for old-style-user-limits *Command-Line `--old-style-user-limits' Format* *Option-File Format* `old-style-user-limits' *Permitted Values * *Type* `boolean' *Default* `FALSE' Enable old-style user limits. (Before MySQL 5.0.3, account resource limits were counted separately for each host from which a user connected rather than per account row in the `user' table.) See *Note user-resources::. * `--one-thread' Options for one-thread *Command-Line `--one-thread' Format* *Option-File Format* `one-thread' Only use one thread (for debugging under Linux). This option is available only if the server is built with debugging enabled. See MySQL Internals: Porting (http://forge.mysql.com/wiki/MySQL_Internals_Porting). As of MySQL 5.1.17, this option is deprecated and is removed in MySQL 5.6. Use `--thread_handling=no-threads' instead. * `--open-files-limit=COUNT' Options for open-files-limit *Command-Line `--open-files-limit=#' Format* *Option-File Format* `open-files-limit' *Option Sets Yes, Variable* `open_files_limit' *Variable Name* `open_files_limit' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `numeric' *Default* `0' *Range* `0-65535' Changes the number of file descriptors available to *Note `mysqld': mysqld. You should try increasing the value of this option if *Note `mysqld': mysqld. gives you the error `Too many open files'. *Note `mysqld': mysqld. uses the option value to reserve descriptors with `setrlimit()'. If the requested number of file descriptors cannot be allocated, *Note `mysqld': mysqld. writes a warning to the error log. *Note `mysqld': mysqld. may attempt to allocate more than the requested number of descriptors (if they are available), using the values of `max_connections' and `table_open_cache' to estimate whether more descriptors will be needed. * `--partition[=VALUE]' Options for partition *Command-Line `--partition' Format* *Option-File Format* `partition' *Option Sets Yes, Variable* `have_partitioning' *Variable Name* `partition' *Variable Scope* Global *Dynamic Variable* No *Disabled by* `skip-partition' *Permitted Values * *Type* `boolean' *Default* `ON' Enables or disables user-defined partitioning support in the MySQL Server. * `--pid-file=PATH' Options for pid-file *Command-Line `--pid-file=file_name' Format* *Option-File Format* `pid-file=file_name' *Option Sets Yes, Variable* `pid_file' *Variable Name* `pid_file' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `file name' The path name of the process ID file. The server creates the file in the data directory unless an absolute path name is given to specify a different directory. This file is used by other programs such as *Note `mysqld_safe': mysqld-safe. to determine the server's process ID. * `--plugin-XXX' Specifies an option that pertains to a server plugin. For example, many storage engines can be built as plugins, and for such engines, options for them can be specified with a `--plugin' prefix. Thus, the `--innodb_file_per_table' option for `InnoDB' can be specified as `--plugin-innodb_file_per_table'. For boolean options that can be enabled or disabled, the `--skip' prefix and other alternative formats are supported as well (see *Note option-modifiers::). For example, `--skip-plugin-innodb_file_per_table' disables `innodb_file_per_table'. The rationale for the `--plugin' prefix is that it enables plugin options to be specified unambigously if there is a name conflict with a built-in server option. For example, were a plugin writer to name a plugin `sql' and implement a `mode' option, the option name might be `--sql-mode', which would conflict with the built-in option of the same name. In such cases, references to the conflicting name are resolved in favor of the built-in option. To avoid the ambiguity, users can specify the plugin option as `--plugin-sql-mode'. Use of the `--plugin' prefix for plugin options is recommended to avoid any question of ambiguity. * `--plugin-load=PLUGIN_LIST' Options for plugin-load *Version Introduced* 5.1.18 *Command-Line `--plugin-load=plugin_list' Format* *Option-File Format* `plugin-load' *Permitted Values * *Type* `string' This option tells the server to load the named plugins at startup. The option value is a semicolon-separated list of `NAME=PLUGIN_LIBRARY' pairs. Each NAME is the name of the plugin, and PLUGIN_LIBRARY is the name of the shared library that contains the plugin code. Each library file must be located in the directory named by the `plugin_dir' system variable. For example, if plugins named `myplug1' and `myplug2' have library files `myplug1.so' and `myplug2.so', use this option to load them at startup: shell> `mysqld --plugin-load=myplug1=myplug1.so;myplug2=myplug2.so' All plugins to load must be named in the same `--plugin-load' option. If multiple `--plugin-load' options are given, only the last one is used. If a plugin library is named without any preceding plugin name, the server loads all plugins in the library. Each plugin is loaded for a single invocation of *Note `mysqld': mysqld. only. After a restart, the plugin is not loaded unless `--plugin-load' is used again. This is in contrast to *Note `INSTALL PLUGIN': install-plugin, which adds an entry to the `mysql.plugins' table to cause the plugin to be loaded for every normal server startup. Under normal startup, the server determines which plugins to load by reading the `mysql.plugins' system table. If the server is started with the `--skip-grant-tables' option, it does not consult the `mysql.plugins' table and does not load plugins listed there. `--plugin-load' enables plugins to be loaded even when `--skip-grant-tables' is given. `--plugin-load' also enables plugins to be loaded at startup under configurations when plugins cannot be loaded at runtime. For additional information about plugin loading, see *Note server-plugin-loading::. This option was added in MySQL 5.1.18. * `--port=PORT_NUM', `-P PORT_NUM' Options for port *Command-Line `--port=#' Format* ** `-P' *Option-File Format* `port' *Option Sets Yes, Variable* `port' *Variable Name* `port' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `numeric' *Default* `3306' The port number to use when listening for TCP/IP connections. The port number must be 1024 or higher unless the server is started by the `root' system user. * `--port-open-timeout=NUM' Options for port-open-timeout *Version Introduced* 5.1.5 *Command-Line `--port-open-timeout=#' Format* *Option-File Format* `port-open-timeout' *Permitted Values * *Type* `numeric' *Default* `0' On some systems, when the server is stopped, the TCP/IP port might not become available immediately. If the server is restarted quickly afterward, its attempt to reopen the port can fail. This option indicates how many seconds the server should wait for the TCP/IP port to become free if it cannot be opened. The default is not to wait. This option was added in MySQL 5.1.5. * `--remove [SERVICE_NAME]' Options for remove *Command-Line `--remove Format* [service_name]' (Windows only) Remove a MySQL Windows service. The default service name is `MySQL' if no SERVICE_NAME value is given. For more information, see *Note windows-start-service::. * `--safe-mode' Options for safe-mode *Command-Line `--safe-mode' Format* *Option-File Format* `safe-mode' *Deprecated* 5.0 Skip some optimization stages. * `--safe-show-database' Options for safe-show-database *Command-Line `--safe-show-database'(until Format* 4.1.1) *Option-File Format* `safe-show-database' *Variable Name* `safe_show_database' *Variable Scope* Global *Dynamic Variable* Yes *Deprecated* 4.0.2 *Permitted Values * *Type* `boolean' This option is deprecated and does not do anything because there is a *Note `SHOW DATABASES': show-databases. privilege that can be used to control access to database names on a per-account basis. See *Note privileges-provided::. `--safe-show-database' is removed in MySQL 5.5. * `--safe-user-create' Options for safe-user-create *Command-Line `--safe-user-create' Format* *Option-File Format* `safe-user-create' *Permitted Values * *Type* `boolean' *Default* `FALSE' If this option is enabled, a user cannot create new MySQL users by using the *Note `GRANT': grant. statement unless the user has the `INSERT' privilege for the `mysql.user' table or any column in the table. If you want a user to have the ability to create new users that have those privileges that the user has the right to grant, you should grant the user the following privilege: GRANT INSERT(user) ON mysql.user TO 'USER_NAME'@'HOST_NAME'; This ensures that the user cannot change any privilege columns directly, but has to use the *Note `GRANT': grant. statement to give privileges to other users. * `--secure-auth' Options for secure-auth *Command-Line `--secure-auth' Format* *Option-File Format* `secure-auth' *Option Sets Yes, Variable* `secure_auth' *Variable Name* `secure_auth' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `boolean' *Default* `FALSE' Disallow authentication by clients that attempt to use accounts that have old (pre-4.1) passwords. * `--secure-file-priv=PATH' Options for secure-file-priv *Version Introduced* 5.1.17 *Command-Line `--secure-file-priv=path' Format* *Option-File Format* `secure-file-priv=path' *Option Sets Yes, Variable* `secure_file_priv' *Variable Name* `secure-file-priv' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `string' This option limits the effect of the `LOAD_FILE()' function and the *Note `LOAD DATA': load-data. and *Note `SELECT ... INTO OUTFILE': select. statements to work only with files in the specified directory. This option was added in MySQL 5.1.17. * `--shared-memory' Enable shared-memory connections by local clients. This option is available only on Windows. * `--shared-memory-base-name=NAME' The name of shared memory to use for shared-memory connections. This option is available only on Windows. The default name is `MYSQL'. The name is case sensitive. * `--skip-concurrent-insert' Turn off the ability to select and insert at the same time on `MyISAM' tables. (This is to be used only if you think you have found a bug in this feature.) See *Note concurrent-inserts::. * `--skip-external-locking' Do not use external locking (system locking). This affects only *Note `MyISAM': myisam-storage-engine. table access. For more information, including conditions under which it can and cannot be used, see *Note external-locking::. External locking has been disabled by default since MySQL 4.0. * `--skip-event-scheduler' Options for skip-event-scheduler *Command-Line `--skip-event-scheduler' Format* ** `--disable-event-scheduler' *Option-File Format* `skip-event-scheduler' Turns the Event Scheduler `OFF'. This is not the same as disabling the Event Scheduler, which requires setting `--event-scheduler=DISABLED'; see The `--event-scheduler' Option, for more information. * `--skip-grant-tables' This option causes the server to start without using the privilege system at all, which gives anyone with access to the server _unrestricted access to all databases_. You can cause a running server to start using the grant tables again by executing *Note `mysqladmin flush-privileges': mysqladmin. or *Note `mysqladmin reload': mysqladmin. command from a system shell, or by issuing a MySQL *Note `FLUSH PRIVILEGES': flush. statement after connecting to the server. This option also suppresses loading of plugins that were installed with the *Note `INSTALL PLUGIN': install-plugin. statement, user-defined functions (UDFs), and, beginning with MySQL 5.1.17, scheduled events. To cause plugins to be loaded anyway, use the `--plugin-load' option. `--skip-grant-tables' is unavailable if MySQL was configured with the `--disable-grant-options' option. See *Note source-configuration-options::. * `--skip-host-cache' Do not use the internal host name cache for faster name-to-IP resolution. Instead, query the DNS server every time a client connects. See *Note dns::. * `--skip-innodb' Disable the `InnoDB' storage engine. In this case, the server will not start if the default storage engine is set to *Note `InnoDB': innodb-storage-engine. Use `--default-storage-engine' to set the default to some other engine if necessary. * `--skip-name-resolve' Do not resolve host names when checking client connections. Use only IP addresses. If you use this option, all `Host' column values in the grant tables must be IP addresses or `localhost'. See *Note dns::. * `--skip-networking' Do not listen for TCP/IP connections at all. All interaction with *Note `mysqld': mysqld. must be made using named pipes or shared memory (on Windows) or Unix socket files (on Unix). This option is highly recommended for systems where only local clients are permitted. See *Note dns::. * `--skip-partition' Options for skip-partition *Command-Line `--skip-partition' Format* ** `--disable-partition' *Option-File Format* `skip-partition' Disables user-defined partitioning. Existing partitioned tables cannot be accessed when the server has been started with this option. * `--ssl*' Options that begin with `--ssl' specify whether to permit clients to connect using SSL and indicate where to find SSL keys and certificates. See *Note ssl-options::. * `--standalone' Options for standalone *Command-Line `--standalone' Format* *Option-File Format* `standalone' *Platform Specific* windows Available on Windows only; instructs the MySQL server not to run as a service. * `--symbolic-links', `--skip-symbolic-links' Options for symbolic-links *Command-Line `--symbolic-links' Format* *Option-File Format* `symbolic-links' Enable or disable symbolic link support. This option has different effects on Windows and Unix: * On Windows, enabling symbolic links enables you to establish a symbolic link to a database directory by creating a `DB_NAME.sym' file that contains the path to the real directory. See *Note windows-symbolic-links::. * On Unix, enabling symbolic links means that you can link a `MyISAM' index file or data file to another directory with the `INDEX DIRECTORY' or `DATA DIRECTORY' options of the *Note `CREATE TABLE': create-table. statement. If you delete or rename the table, the files that its symbolic links point to also are deleted or renamed. See *Note symbolic-links-to-tables::. * `--skip-safemalloc' Options for skip-safemalloc *Command-Line `--skip-safemalloc' Format* *Option-File Format* `skip-safemalloc' If MySQL is configured with `--with-debug=full', all MySQL programs check for memory overruns during each memory allocation and memory freeing operation. This checking is very slow, so for the server you can avoid it when you do not need it by using the `--skip-safemalloc' option. * `--skip-show-database' Options for skip-show-database *Command-Line `--skip-show-database' Format* *Option-File Format* `skip-show-database' *Option Sets Yes, Variable* `skip_show_database' *Variable Name* `skip_show_database' *Variable Scope* Global *Dynamic Variable* No With this option, the *Note `SHOW DATABASES': show-databases. statement is permitted only to users who have the `SHOW DATABASES' privilege, and the statement displays all database names. Without this option, *Note `SHOW DATABASES': show-databases. is permitted to all users, but displays each database name only if the user has the `SHOW DATABASES' privilege or some privilege for the database. Note that _any_ global privilege is considered a privilege for the database. * `--skip-stack-trace' Options for skip-stack-trace *Command-Line `--skip-stack-trace' Format* *Option-File Format* `skip-stack-trace' Do not write stack traces. This option is useful when you are running *Note `mysqld': mysqld. under a debugger. On some systems, you also must use this option to get a core file. See MySQL Internals: Porting (http://forge.mysql.com/wiki/MySQL_Internals_Porting). * `--skip-thread-priority' Options for skip-thread-priority *Version Deprecated* 5.1.29 *Command-Line `--skip-thread-priority' Format* *Option-File Format* `skip-thread-priority' *Deprecated* 5.1.29 Disable using thread priorities for faster response time. This option is deprecated as of MySQL 5.1.29 and is removed in MySQL 5.6. Prior to MySQL 5.1.29, *Note `mysqld': mysqld. makes a large number of invalid calls to thread scheduling routines on Linux. These calls do not affect performance noticeably but may be a source of `noise' for debugging tools. For example, they can overwhelm other information of more interest in kernel logs. To avoid these calls, start the server with the `--skip-thread-priority' option. * `--slow-query-log[={0|1}]' Options for slow-query-log *Version Introduced* 5.1.12 *Command-Line `--slow-query-log'5.1.29 Format* *Option-File Format* `slow-query-log'5.1.29 *Option Sets Yes, Variable* `slow_query_log' *Variable Name* `slow_query_log' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `boolean' *Default* `OFF' Specify the initial slow query log state. With no argument or an argument of 1, the `--slow-query-log' option enables the log. If omitted or given with an argument of 0, the option disables the log. This option was added in MySQL 5.1.12. * `--socket=PATH' Options for socket *Command-Line `--socket=name' Format* *Option-File Format* `socket' *Option Sets Yes, Variable* `socket' *Variable Name* `socket' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `file name' *Default* `/tmp/mysql.sock' On Unix, this option specifies the Unix socket file to use when listening for local connections. The default value is `/tmp/mysql.sock'. If this option is given, the server creates the file in the data directory unless an absolute path name is given to specify a different directory. On Windows, the option specifies the pipe name to use when listening for local connections that use a named pipe. The default value is `MySQL' (not case sensitive). * `--sql-mode=VALUE[,VALUE[,VALUE...]]' Options for sql-mode *Command-Line `--sql-mode=name' Format* *Option-File Format* `sql-mode' *Option Sets Yes, Variable* `sql_mode' *Variable Name* `sql_mode' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `set' *Default* `''' *Valid Values* `ALLOW_INVALID_DATES' `ANSI_QUOTES' `ERROR_FOR_DIVISION_BY_ZERO' `HIGH_NOT_PRECEDENCE' `IGNORE_SPACE' `NO_AUTO_CREATE_USER' `NO_AUTO_VALUE_ON_ZERO' `NO_BACKSLASH_ESCAPES' `NO_DIR_IN_CREATE' `NO_ENGINE_SUBSTITUTION' `NO_FIELD_OPTIONS' `NO_KEY_OPTIONS' `NO_TABLE_OPTIONS' `NO_UNSIGNED_SUBTRACTION' `NO_ZERO_DATE' `NO_ZERO_IN_DATE' `ONLY_FULL_GROUP_BY' `PAD_CHAR_TO_FULL_LENGTH' `PIPES_AS_CONCAT' `REAL_AS_FLOAT' `STRICT_ALL_TABLES' `STRICT_TRANS_TABLES' Set the SQL mode. See *Note server-sql-mode::. * `--sysdate-is-now' Options for sysdate-is-now *Version Introduced* 5.1.8 *Command-Line `--sysdate-is-now' Format* *Option-File Format* `sysdate-is-now' *Permitted Values * *Type* `boolean' *Default* `FALSE' `SYSDATE()' by default returns the time at which it executes, not the time at which the statement in which it occurs begins executing. This differs from the behavior of `NOW()'. This option causes `SYSDATE()' to be an alias for `NOW()'. For information about the implications for binary logging and replication, see the description for `SYSDATE()' in *Note date-and-time-functions:: and for `SET TIMESTAMP' in *Note server-system-variables::. This option was added in MySQL 5.1.8. * `--tc-heuristic-recover={COMMIT|ROLLBACK}' Options for tc-heuristic-recover *Command-Line `--tc-heuristic-recover=name' Format* *Option-File Format* `tc-heuristic-recover' *Permitted Values * *Type* `enumeration' *Valid Values* `COMMIT' `RECOVER' The type of decision to use in the heuristic recovery process. Currently, this option is unused. * `--temp-pool' Options for temp-pool *Command-Line `--temp-pool' Format* *Option-File Format* `temp-pool' *Permitted Values * *Type* `boolean' *Default* `TRUE' This option causes most temporary files created by the server to use a small set of names, rather than a unique name for each new file. This works around a problem in the Linux kernel dealing with creating many new files with different names. With the old behavior, Linux seems to `leak' memory, because it is being allocated to the directory entry cache rather than to the disk cache. As of MySQL 5.1.31, this option is ignored except on Linux. * `--transaction-isolation=LEVEL' Options for transaction-isolation *Command-Line `--transaction-isolation=name' Format* *Option-File Format* `transaction-isolation' *Option Sets Yes, Variable* `tx_isolation' *Permitted Values * *Type* `enumeration' *Valid Values* `READ-UNCOMMITTED' `READ-COMMITTED' `REPEATABLE-READ' `SERIALIZABLE' Sets the default transaction isolation level. The `level' value can be `READ-UNCOMMITTED', `READ-COMMITTED', `REPEATABLE-READ', or `SERIALIZABLE'. See *Note set-transaction::. The default transaction isolation level can also be set in the running server using *Note `SET TRANSACTION': set-transaction. or by setting the `tx_isolation' system variable. * `--tmpdir=PATH', `-t PATH' Options for tmpdir *Command-Line `--tmpdir=path' Format* ** `-t' *Option-File Format* `tmpdir' *Option Sets Yes, Variable* `tmpdir' *Variable Name* `tmpdir' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `file name' The path of the directory to use for creating temporary files. It might be useful if your default `/tmp' directory resides on a partition that is too small to hold temporary tables. This option accepts several paths that are used in round-robin fashion. Paths should be separated by colon characters (``:'') on Unix and semicolon characters (``;'') on Windows, NetWare, and OS/2. If the MySQL server is acting as a replication slave, you should not set `--tmpdir' to point to a directory on a memory-based file system or to a directory that is cleared when the server host restarts. For more information about the storage location of temporary files, see *Note temporary-files::. A replication slave needs some of its temporary files to survive a machine restart so that it can replicate temporary tables or *Note `LOAD DATA INFILE': load-data. operations. If files in the temporary file directory are lost when the server restarts, replication fails. * `--user={USER_NAME|USER_ID}', `-u {USER_NAME|USER_ID}' Options for user *Command-Line `--user=name' Format* ** `-u name' *Option-File Format* `user' *Permitted Values * *Type* `string' Run the *Note `mysqld': mysqld. server as the user having the name USER_NAME or the numeric user ID USER_ID. (`User' in this context refers to a system login account, not a MySQL user listed in the grant tables.) This option is _mandatory_ when starting *Note `mysqld': mysqld. as `root'. The server changes its user ID during its startup sequence, causing it to run as that particular user rather than as `root'. See *Note security-guidelines::. To avoid a possible security hole where a user adds a `--user=root' option to a `my.cnf' file (thus causing the server to run as `root'), *Note `mysqld': mysqld. uses only the first `--user' option specified and produces a warning if there are multiple `--user' options. Options in `/etc/my.cnf' and `$MYSQL_HOME/my.cnf' are processed before command-line options, so it is recommended that you put a `--user' option in `/etc/my.cnf' and specify a value other than `root'. The option in `/etc/my.cnf' is found before any other `--user' options, which ensures that the server runs as a user other than `root', and that a warning results if any other `--user' option is found. * `--verbose', `-v' Use this option with the `--help' option for detailed help. * `--version', `-V' Display version information and exit. You can assign a value to a server system variable by using an option of the form `--VAR_NAME=VALUE'. For example, `--key_buffer_size=32M' sets the `key_buffer_size' variable to a value of 32MB. Note that when you assign a value to a variable, MySQL might automatically correct the value to stay within a given range, or adjust the value to the closest permissible value if only certain values are permitted. If you want to restrict the maximum value to which a variable can be set at runtime with *Note `SET': set-option, you can define this by using the `--maximum-VAR_NAME=VALUE' command-line option. You can change the values of most system variables for a running server with the *Note `SET': set-option. statement. See *Note set-option::. *Note server-system-variables::, provides a full description for all variables, and additional information for setting them at server startup and runtime. *Note server-parameters::, includes information on optimizing the server by tuning system variables.  File: manual.info, Node: server-system-variables, Next: using-system-variables, Prev: server-options, Up: mysqld-server 6.1.3 Server System Variables ----------------------------- The MySQL server maintains many system variables that indicate how it is configured. Each system variable has a default value. System variables can be set at server startup using options on the command line or in an option file. Most of them can be changed dynamically while the server is running by means of the *Note `SET': set-option. statement, which enables you to modify operation of the server without having to stop and restart it. You can refer to system variable values in expressions. There are several ways to see the names and values of system variables: * To see the values that a server will use based on its compiled-in defaults and any option files that it reads, use this command: mysqld --verbose --help * To see the values that a server will use based on its compiled-in defaults, ignoring the settings in any option files, use this command: mysqld --no-defaults --verbose --help * To see the current values used by a running server, use the *Note `SHOW VARIABLES': show-variables. statement. This section provides a description of each system variable. Variables with no version indicated are present in all MySQL 5.1 releases. For historical information concerning their implementation, please see `http://dev.mysql.com/doc/refman/5.0/en/', and `http://dev.mysql.com/doc/refman/4.1/en/'. The following table lists all available system variables: *System Variable Summary* Name Cmd-Line Option file System Var Var Scope Dynamic auto_increment_incrementYes Yes Yes Both Yes auto_increment_offsetYes Yes Yes Both Yes autocommit Yes Yes Yes Session Yes automatic_sp_privileges Yes Global Yes back_log Yes Yes Yes Global No basedir Yes Yes Yes Global No big-tables Yes Yes Yes - _Variable_: Yes Session Yes big_tables bind-address Yes Yes Yes Global No binlog_cache_sizeYes Yes Yes Global Yes binlog_direct_non_transactional_updatesYes Yes Yes Both Yes binlog-format Yes Yes Yes - _Variable_: Yes Both Yes binlog_format bulk_insert_buffer_sizeYes Yes Yes Both Yes character_set_client Yes Both Yes character_set_connection Yes Both Yes character_set_database Yes Both Yes This option is dynamic, but only the server should set this information. You should not set the value of this variable manually. character-set-filesystemYes Yes Yes - _Variable_: Yes Both Yes character_set_filesystem character_set_results Yes Both Yes character-set-serverYes Yes Yes - _Variable_: Yes Both Yes character_set_server character_set_system Yes Global No character-sets-dirYes Yes No - _Variable_: Yes Global No character_sets_dir collation_connection Yes Both Yes collation_database Yes Both Yes This option is dynamic, but only the server should set this information. You should not set the value of this variable manually. collation-serverYes Yes Yes - _Variable_: Yes Both Yes collation_server completion_typeYes Yes Yes Both Yes concurrent_insertYes Yes Yes Global Yes connect_timeoutYes Yes Yes Global Yes datadir Yes Yes Yes Global No date_format Yes Both No datetime_format Yes Both No debug Yes Yes Yes Both Yes debug_sync Yes Both Yes default-storage-engineYes Yes Yes Both Yes default_week_formatYes Yes Yes Both Yes delay-key-writeYes Yes Yes - _Variable_: Yes Global Yes delay_key_write delayed_insert_limitYes Yes Yes Global Yes delayed_insert_timeoutYes Yes Yes Global Yes delayed_queue_sizeYes Yes Yes Global Yes div_precision_incrementYes Yes Yes Both Yes engine-condition-pushdownYes Yes Yes - _Variable_: Yes Both Yes engine_condition_pushdown error_count Yes Session No event-schedulerYes Yes Yes - _Variable_: Yes Global Yes event_scheduler expire_logs_daysYes Yes Yes Global Yes flush Yes Yes Yes Global Yes flush_time Yes Yes Yes Global Yes foreign_key_checks Yes Session Yes ft_boolean_syntaxYes Yes Yes Global Yes ft_max_word_lenYes Yes Yes Global No ft_min_word_lenYes Yes Yes Global No ft_query_expansion_limitYes Yes Yes Global No ft_stopword_fileYes Yes Yes Global No general-log Yes Yes Yes - _Variable_: Yes Global Yes general_log general_log_fileYes Yes Yes Global Yes group_concat_max_lenYes Yes Yes Both Yes have_archive Yes Global No have_blackhole_engine Yes Global No have_community_features Yes Global No have_compress Yes Global No have_crypt Yes Global No have_csv Yes Global No have_dynamic_loading Yes Global No have_example_engine Yes Global No have_federated_engine Yes Global No have_geometry Yes Global No have_innodb Yes Global No have_isam Yes Global No have_merge_engine Yes Global No have_ndbcluster Yes Global No have_openssl Yes Global No have_partition_engine Yes Global No have_partitioning Yes Global No have_query_cache Yes Global No have_raid Yes Global No have_row_based_replication Yes Global No have_rtree_keys Yes Global No have_ssl Yes Global No have_symlink Yes Global No hostname Yes Global No identity Yes Session Yes ignore-builtin-innodbYes Yes No - _Variable_: Yes Global No ignore_builtin_innodb init_connect Yes Yes Yes Global Yes init-file Yes Yes No - _Variable_: Yes Global No init_file init_slave Yes Yes Yes Global Yes innodb_adaptive_flushingYes Yes Yes Global Yes innodb_adaptive_hash_indexYes Yes Yes Global No innodb_additional_mem_pool_sizeYes Yes Yes Global No innodb_autoextend_incrementYes Yes Yes Global Yes innodb_autoinc_lock_modeYes Yes Yes Global No innodb_buffer_pool_awe_mem_mbYes Yes Yes Global No innodb_buffer_pool_sizeYes Yes Yes Global No innodb_change_bufferingYes Yes Yes Global Yes innodb_checksumsYes Yes Yes Global No innodb_commit_concurrencyYes Yes Yes Global Yes innodb_concurrency_ticketsYes Yes Yes Global Yes innodb_data_file_pathYes Yes Yes Global No innodb_data_home_dirYes Yes Yes Global No innodb_doublewriteYes Yes Yes Global No innodb_fast_shutdownYes Yes Yes Global Yes innodb_file_formatYes Yes Yes Global Yes innodb_file_format_checkYes Yes Yes Global Yes innodb_file_io_threadsYes Yes Yes Global No innodb_file_per_tableYes Yes Yes Global No innodb_flush_log_at_trx_commitYes Yes Yes Global Yes innodb_flush_methodYes Yes Yes Global No innodb_force_recoveryYes Yes Yes Global No innodb_io_capacityYes Yes Yes Global No innodb_lock_wait_timeoutYes Yes Yes Both Yes innodb_locks_unsafe_for_binlogYes Yes Yes Global No innodb_log_arch_dirYes Yes Yes Global No innodb_log_archiveYes Yes Yes Global No innodb_log_buffer_sizeYes Yes Yes Global No innodb_log_file_sizeYes Yes Yes Global No innodb_log_files_in_groupYes Yes Yes Global No innodb_log_group_home_dirYes Yes Yes Global No innodb_max_dirty_pages_pctYes Yes Yes Global Yes innodb_max_purge_lagYes Yes Yes Global Yes innodb_mirrored_log_groupsYes Yes Yes Global No innodb_old_blocks_pctYes Yes Yes Global Yes innodb_old_blocks_timeYes Yes Yes Global Yes innodb_open_filesYes Yes Yes Global No innodb_read_ahead_thresholdYes Yes Yes Global Yes innodb_read_io_threadsYes Yes Yes Global No innodb_replication_delayYes Yes Yes Global Yes innodb_rollback_on_timeoutYes Yes Yes Global No innodb_spin_wait_delayYes Yes Yes Global Yes innodb_stats_on_metadataYes Yes Yes Global Yes innodb_stats_sample_pagesYes Yes Yes Global Yes innodb_strict_modeYes Yes Yes Both Yes innodb_support_xaYes Yes Yes Both Yes innodb_sync_spin_loopsYes Yes Yes Global Yes innodb_table_locksYes Yes Yes Both Yes innodb_thread_concurrencyYes Yes Yes Global Yes innodb_thread_sleep_delayYes Yes Yes Global Yes innodb_use_legacy_cardinality_algorithmYes Yes Yes Global Yes innodb_use_sys_mallocYes Yes Yes Global No innodb_version Yes Global No innodb_write_io_threadsYes Yes Yes Global No insert_id Yes Session Yes interactive_timeoutYes Yes Yes Both Yes join_buffer_sizeYes Yes Yes Both Yes keep_files_on_createYes Yes Yes Both Yes key_buffer_sizeYes Yes Yes Global Yes key_cache_age_thresholdYes Yes Yes Global Yes key_cache_block_sizeYes Yes Yes Global Yes key_cache_division_limitYes Yes Yes Global Yes language Yes Yes Yes Global No large_files_support Yes Global No large_page_size Yes Global No large-pages Yes Yes No - _Variable_: Yes Global No large_pages last_insert_id Yes Session Yes lc_time_names Yes Both Yes license Yes Global No local_infile Yes Global Yes locked_in_memory Yes Global No log Yes Yes Yes Global Yes log_bin Yes Global No log-bin Yes Yes Yes Global No log-bin-trust-function-creatorsYes Yes Yes - _Variable_: Yes Global Yes log_bin_trust_function_creators log-bin-trust-routine-creatorsYes Yes Yes - _Variable_: Yes Global Yes log_bin_trust_routine_creators log-error Yes Yes No - _Variable_: Yes Global No log_error log-output Yes Yes Yes - _Variable_: Yes Global Yes log_output log-queries-not-using-indexesYes Yes Yes - _Variable_: Yes Global Yes log_queries_not_using_indexes log-slave-updatesYes Yes No - _Variable_: Yes Global No log_slave_updates log-slow-queriesYes Yes Yes - _Variable_: Yes Global Yes log_slow_queries log-warnings Yes Yes Yes - _Variable_: Yes Both Yes log_warnings long_query_timeYes Yes Yes Both Yes low-priority-updatesYes Yes Yes - _Variable_: Yes Both Yes low_priority_updates lower_case_file_systemYes Yes Yes Global No lower_case_table_namesYes Yes Yes Global No max_allowed_packetYes Yes Yes Global Yes max_binlog_cache_sizeYes Yes Yes Global Yes max_binlog_sizeYes Yes Yes Global Yes max_connect_errorsYes Yes Yes Global Yes max_connectionsYes Yes Yes Global Yes max_delayed_threadsYes Yes Yes Both Yes max_error_countYes Yes Yes Both Yes max_heap_table_sizeYes Yes Yes Both Yes max_insert_delayed_threads Yes Both Yes max_join_size Yes Yes Yes Both Yes max_length_for_sort_dataYes Yes Yes Both Yes max_long_data_sizeYes Yes Yes Global No max_prepared_stmt_countYes Yes Yes Global Yes max_relay_log_sizeYes Yes Yes Global Yes max_seeks_for_keyYes Yes Yes Both Yes max_sort_lengthYes Yes Yes Both Yes max_sp_recursion_depthYes Yes Yes Both Yes max_tmp_tables Yes Yes Yes Both Yes max_user_connectionsYes Yes Yes Both Yes max_write_lock_countYes Yes Yes Global Yes memlock Yes Yes Yes Global No min-examined-row-limitYes Yes Yes Both Yes multi_range_countYes Yes Yes Both Yes myisam_data_pointer_sizeYes Yes Yes Global Yes myisam_max_sort_file_sizeYes Yes Yes Global Yes myisam_mmap_sizeYes Yes Yes Global No myisam_recover_options Yes Global No myisam_repair_threadsYes Yes Yes Both Yes myisam_sort_buffer_sizeYes Yes Yes Both Yes myisam_stats_methodYes Yes Yes Both Yes myisam_use_mmapYes Yes Yes Global Yes named_pipe Yes Global No ndb_autoincrement_prefetch_szYes Yes Yes Both Yes ndb-batch-size Yes Yes Yes Global No ndb-blob-read-batch-bytesYes Yes Yes Both Yes ndb-blob-write-batch-bytesYes Yes Yes Both Yes ndb_cache_check_timeYes Yes Yes Global Yes ndb-cluster-connection-poolYes Yes Yes Global No ndb_extra_loggingYes Yes Yes Global Yes ndb_force_send Yes Yes Yes Both Yes ndb_join_pushdown Yes Global No ndb-log-apply-statusYes Yes No - _Variable_: Yes Global No ndb_log_apply_status ndb_log_bin Yes Yes Both Yes ndb_log_binlog_indexYes Yes Global Yes ndb_log_empty_epochsYes Yes Yes Global Yes *Note Yes Global No ndb_log_orig: mysql-cluster-replication-schema. ndb-log-update-as-writeYes Yes Yes Global Yes ndb_log_updated_onlyYes Yes Yes Global Yes ndb_optimization_delay Yes Global Yes ndb_table_no_logging Yes Session Yes ndb_table_temporary Yes Session Yes ndb_use_copying_alter_table Yes Both No ndb_use_exact_count Yes Both Yes ndb_use_transactionsYes Yes Yes Both Yes ndb-wait-connectedYes Yes Yes Global No ndb-wait-setup Yes Yes Yes Global No ndbinfo_database Yes Global No ndbinfo_max_bytesYes Yes Both Yes ndbinfo_max_rowsYes Yes Both Yes ndbinfo_show_hiddenYes Yes Both Yes ndbinfo_table_prefixYes Yes Both Yes ndbinfo_version Yes Global No net_buffer_lengthYes Yes Yes Both Yes net_read_timeoutYes Yes Yes Both Yes net_retry_countYes Yes Yes Both Yes net_write_timeoutYes Yes Yes Both Yes new Yes Yes Yes Both Yes old Yes Yes Yes Global No old-alter-tableYes Yes Yes - _Variable_: Yes Both Yes old_alter_table old-passwords Yes Yes Yes - _Variable_: Yes Both Yes old_passwords open-files-limitYes Yes No - _Variable_: Yes Global No open_files_limit optimizer_prune_levelYes Yes Yes Both Yes optimizer_search_depthYes Yes Yes Both Yes optimizer_switchYes Yes Yes Both Yes partition Yes Yes No - _Variable_: Yes Global No have_partitioning pid-file Yes Yes No - _Variable_: Yes Global No pid_file plugin_dir Yes Yes Yes Global No port Yes Yes Yes Global No preload_buffer_sizeYes Yes Yes Both Yes prepared_stmt_count Yes Global No profiling Yes Session Yes profiling_history_size Yes Both Yes protocol_version Yes Global No pseudo_thread_id Yes Session Yes query_alloc_block_sizeYes Yes Yes Both Yes query_cache_limitYes Yes Yes Global Yes query_cache_min_res_unitYes Yes Yes Global Yes query_cache_sizeYes Yes Yes Global Yes query_cache_typeYes Yes Yes Both Yes query_cache_wlock_invalidateYes Yes Yes Both Yes query_prealloc_sizeYes Yes Yes Both Yes rand_seed1 Yes Session Yes rand_seed2 Yes Session Yes range_alloc_block_sizeYes Yes Yes Both Yes read_buffer_sizeYes Yes Yes Both Yes read_only Yes Yes Yes Global Yes read_rnd_buffer_sizeYes Yes Yes Both Yes relay-log-indexYes Yes No - _Variable_: Yes Both No relay_log_index relay_log_indexYes Yes Yes Global No relay_log_info_fileYes Yes Yes Global No relay_log_purgeYes Yes Yes Global Yes relay_log_space_limitYes Yes Yes Global No report-host Yes Yes No - _Variable_: Yes Global No report_host report-passwordYes Yes No - _Variable_: Yes Global No report_password report-port Yes Yes No - _Variable_: Yes Global No report_port report-user Yes Yes No - _Variable_: Yes Global No report_user rpl_recovery_rank Yes Global Yes safe-show-databaseYes Yes Yes Global Yes secure-auth Yes Yes Yes - _Variable_: Yes Global Yes secure_auth secure-file-privYes Yes No - _Variable_: Yes Global No secure_file_priv server-id Yes Yes Yes - _Variable_: Yes Global Yes server_id server-id-bits Yes Yes No - _Variable_: Yes Global No server_id_bits shared_memory Yes Global No shared_memory_base_name Yes Global No skip-external-lockingYes Yes No - _Variable_: Yes Global No skip_external_locking skip-name-resolveYes Yes No - _Variable_: Yes Global No skip_name_resolve skip-networkingYes Yes No - _Variable_: Yes Global No skip_networking skip-show-databaseYes Yes No - _Variable_: Yes Global No skip_show_database slave_allow_batchingYes Yes Yes Global Yes slave_compressed_protocolYes Yes Yes Global Yes slave_exec_mode Yes Global Yes slave-load-tmpdirYes Yes No - _Variable_: Yes Global No slave_load_tmpdir slave-net-timeoutYes Yes Yes - _Variable_: Yes Global Yes slave_net_timeout slave-skip-errorsYes Yes No - _Variable_: Yes Global No slave_skip_errors slave_transaction_retriesYes Yes Yes Global Yes slave_type_conversionsYes Yes Yes Global No slow_launch_timeYes Yes Yes Global Yes slow-query-log Yes Yes Yes - _Variable_: Yes Global Yes slow_query_log slow_query_log_fileYes Yes Yes Global Yes socket Yes Yes Yes Global No sort_buffer_sizeYes Yes Yes Both Yes sql_auto_is_null Yes Session Yes sql_big_selects Yes Session Yes sql_big_tables Yes Session Yes sql_buffer_result Yes Session Yes sql_log_bin Yes Session Yes sql_log_off Yes Session Yes sql_log_update Yes Session Yes sql_low_priority_updates Yes Both Yes sql_max_join_size Yes Both Yes sql-mode Yes Yes Yes - _Variable_: Yes Both Yes sql_mode sql_notes Yes Session Yes sql_quote_show_create Yes Session Yes sql_safe_updates Yes Session Yes sql_select_limit Yes Both Yes sql_slave_skip_counter Yes Global Yes sql_warnings Yes Session Yes ssl-ca Yes Yes No - _Variable_: Yes Global No ssl_ca ssl-capath Yes Yes No - _Variable_: Yes Global No ssl_capath ssl-cert Yes Yes No - _Variable_: Yes Global No ssl_cert ssl-cipher Yes Yes No - _Variable_: Yes Global No ssl_cipher ssl-key Yes Yes No - _Variable_: Yes Global No ssl_key storage_engine Yes Both Yes sync_binlog Yes Yes Yes Global Yes sync_frm Yes Yes Yes Global Yes system_time_zone Yes Global No table_cache Yes Yes Yes Global Yes table_definition_cacheYes Yes Yes Global Yes table_lock_wait_timeoutYes Yes Yes Global Yes table_open_cacheYes Yes Yes Global Yes table_type Yes Both Yes thread_cache_sizeYes Yes Yes Global Yes thread_concurrencyYes Yes Yes Global No thread_handlingYes Yes Yes Global No thread_stack Yes Yes Yes Global No time_format Yes Both No time_zone Yes Yes Yes Both Yes timed_mutexes Yes Yes Yes Global Yes timestamp Yes Session Yes tmp_table_size Yes Yes Yes Both Yes tmpdir Yes Yes Yes Global No transaction_alloc_block_sizeYes Yes Yes Both Yes transaction_allow_batching Yes Session Yes transaction_prealloc_sizeYes Yes Yes Both Yes tx_isolation Yes Both Yes unique_checks Yes Session Yes updatable_views_with_limitYes Yes Yes Both Yes version Yes Global No version_comment Yes Global No version_compile_machine Yes Global No version_compile_os Yes Global No wait_timeout Yes Yes Yes Both Yes warning_count Yes Session No For additional system variable information, see these sections: * *Note using-system-variables::, discusses the syntax for setting and displaying system variable values. * *Note dynamic-system-variables::, lists the variables that can be set at runtime. * Information on tuning system variables can be found in *Note server-parameters::. * *Note innodb-parameters::, lists `InnoDB' system variables. * *Note mysql-cluster-system-variables::, lists system variables which are specific to MySQL Cluster. * For information on server system variables specific to replication, see *Note replication-options::. *Note*: Some of the following variable descriptions refer to `enabling' or `disabling' a variable. These variables can be enabled with the *Note `SET': set-option. statement by setting them to `ON' or `1', or disabled by setting them to `OFF' or `0'. However, to set such a variable on the command line or in an option file, you must set it to `1' or `0'; setting it to `ON' or `OFF' will not work. For example, on the command line, `--delay_key_write=1' works but `--delay_key_write=ON' does not. Some system variables control the size of buffers or caches. For a given buffer, the server might need to allocate internal data structures. These structures typically are allocated from the total memory allocated to the buffer, and the amount of space required might be platform dependent. This means that when you assign a value to a system variable that controls a buffer size, the amount of space actually available might differ from the value assigned. In some cases, the amount might be less than the value assigned. It is also possible that the server will adjust a value upward. For example, if you assign a value of 0 to a variable for which the minimal value is 1024, the server will set the value to 1024. Values for buffer sizes, lengths, and stack sizes are given in bytes unless otherwise specified. Some system variables take file name values. Unless otherwise specified, the default file location is the data directory if the value is a relative path name. To specify the location explicitly, use an absolute path name. Suppose that the data directory is `/var/mysql/data'. If a file-valued variable is given as a relative path name, it will be located under `/var/mysql/data'. If the value is an absolute path name, its location is as given by the path name. * `autocommit' Options for autocommit *Command-Line `--autocommit[=#]' Format* *Option-File Format* `autocommit' *Option Sets Yes, Variable* `autocommit' *Variable Name* `autocommit' *Variable Scope* Session *Dynamic Variable* Yes *Permitted Values * *Type* `boolean' The autocommit mode. If set to 1, all changes to a table take effect immediately. If set to 0, you must use *Note `COMMIT': commit. to accept a transaction or *Note `ROLLBACK': commit. to cancel it. If `autocommit' is 0 and you change it to 1, MySQL performs an automatic *Note `COMMIT': commit. of any open transaction. Another way to begin a transaction is to use a *Note `START TRANSACTION': commit. or *Note `BEGIN': commit. statement. See *Note commit::. By default, client connections begin with `autocommit' set to 1. To cause clients to begin with a default of 0, set the server's `init_connect' system variable: SET GLOBAL init_connect='SET autocommit=0'; The `init_connect' variable can also be set on the command line or in an option file. To set the variable as just shown using an option file, include these lines: [mysqld] init_connect='SET autocommit=0' The content of `init_connect' is not executed for users that have the `SUPER' privilege. * `automatic_sp_privileges' Options for automatic_sp_privileges *Variable Name* `automatic_sp_privileges' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `boolean' *Default* `TRUE' When this variable has a value of 1 (the default), the server automatically grants the `EXECUTE' and `ALTER ROUTINE' privileges to the creator of a stored routine, if the user cannot already execute and alter or drop the routine. (The `ALTER ROUTINE' privilege is required to drop the routine.) The server also automatically drops those privileges from the creator when the routine is dropped. If `automatic_sp_privileges' is 0, the server does not automatically add or drop these privileges. The creator of a routine is the account used to execute the `CREATE' statement for it. This might not be the same as the account named as the `DEFINER' in the routine definition. See also *Note stored-routines-privileges::. * `back_log' Options for back_log *Command-Line `--back_log=#' Format* *Option-File Format* `back_log' *Option Sets Yes, Variable* `back_log' *Variable Name* `back_log' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `numeric' *Default* `50' *Range* `1-65535' The number of outstanding connection requests MySQL can have. This comes into play when the main MySQL thread gets very many connection requests in a very short time. It then takes some time (although very little) for the main thread to check the connection and start a new thread. The `back_log' value indicates how many requests can be stacked during this short time before MySQL momentarily stops answering new requests. You need to increase this only if you expect a large number of connections in a short period of time. In other words, this value is the size of the listen queue for incoming TCP/IP connections. Your operating system has its own limit on the size of this queue. The manual page for the Unix `listen()' system call should have more details. Check your OS documentation for the maximum value for this variable. `back_log' cannot be set higher than your operating system limit. * `basedir' Options for basedir *Command-Line `--basedir=path' Format* ** `-b' *Option-File Format* `basedir' *Option Sets Yes, Variable* `basedir' *Variable Name* `basedir' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `file name' The MySQL installation base directory. This variable can be set with the `--basedir' option. Relative path names for other variables usually are resolved relative to the base directory. * `big_tables' If set to 1, all temporary tables are stored on disk rather than in memory. This is a little slower, but the error `The table TBL_NAME is full' does not occur for *Note `SELECT': select. operations that require a large temporary table. The default value for a new connection is 0 (use in-memory temporary tables). Normally, you should never need to set this variable, because in-memory tables are automatically converted to disk-based tables as required. *Note*: This variable was formerly named `sql_big_tables'. * `bulk_insert_buffer_size' Options for bulk_insert_buffer_size *Command-Line `--bulk_insert_buffer_size=#' Format* *Option-File Format* `bulk_insert_buffer_size' *Option Sets Yes, Variable* `bulk_insert_buffer_size' *Variable Name* `bulk_insert_buffer_size' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Platform Bit Size* `32' *Type* `numeric' *Default* `8388608' *Range* `0-4294967295' *Permitted Values * *Platform Bit Size* `64' *Type* `numeric' *Default* `8388608' *Range* `0-18446744073709547520' `MyISAM' uses a special tree-like cache to make bulk inserts faster for *Note `INSERT ... SELECT': insert-select, `INSERT ... VALUES (...), (...), ...', and *Note `LOAD DATA INFILE': load-data. when adding data to nonempty tables. This variable limits the size of the cache tree in bytes per thread. Setting it to 0 disables this optimization. The default value is 8MB. * `character_set_client' Options for character_set_client *Variable Name* `character_set_client' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `string' The character set for statements that arrive from the client. The session value of this variable is set using the character set requested by the client when the client connects to the server. (Many clients support a `--default-character-set' option to enable this character set to be specified explicitly. See also *Note charset-connection::.) The global value of the variable is used to set the session value in cases when the client-requested value is unknown or not available, or the server is configured to ignore client requests: * The client is from a version of MySQL older than MySQL 4.1, and thus does not request a character set. * The client requests a character set not known to the server. For example, a Japanese-enabled client requests `sjis' when connecting to a server not configured with `sjis' support. * *Note `mysqld': mysqld. was started with the `--skip-character-set-client-handshake' option, which causes it to ignore client character set configuration. This reproduces MySQL 4.0 behavior and is useful should you wish to upgrade the server without upgrading all the clients. `ucs2' cannot be used as a client character set, which means that it also does not work for `SET NAMES' or `SET CHARACTER SET'. * `character_set_connection' Options for character_set_connection *Variable Name* `character_set_connection' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `string' The character set for the current connection. Used for literals that do not have an explicit character set specification and for number-to-string conversion. * `character_set_database' Options for character_set_database *Variable Name* `character_set_database' *Variable Scope* Global, Session *Dynamic Variable* Yes *Footnote* This option is dynamic, but only the server should set this information. You should not set the value of this variable manually. *Permitted Values * *Type* `string' The character set used by the default database. The server sets this variable whenever the default database changes. If there is no default database, the variable has the same value as `character_set_server'. * `character_set_filesystem' Options for character-set-filesystem *Version Introduced* 5.1.6 *Command-Line `--character-set-filesystem=name' Format* *Option-File Format* `character-set-filesystem' *Option Sets Yes, Variable* `character_set_filesystem' *Variable Name* `character_set_filesystem' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `string' The file system character set. This variable is used to interpret string literals that refer to file names, such as in the *Note `LOAD DATA INFILE': load-data. and *Note `SELECT ... INTO OUTFILE': select. statements and the `LOAD_FILE()' function. Such file names are converted from `character_set_client' to `character_set_filesystem' before the file opening attempt occurs. The default value is `binary', which means that no conversion occurs. For systems on which multi-byte file names are permitted, a different value may be more appropriate. For example, if the system represents file names using UTF-8, set `character_set_filesystem' to `'utf8''. This variable was added in MySQL 5.1.6. * `character_set_results' Options for character_set_results *Variable Name* `character_set_results' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `string' The character set used for returning query results such as result sets or error messages to the client. * `character_set_server' Options for character-set-server *Command-Line `--character-set-server' Format* *Option-File Format* `character-set-server' *Option Sets Yes, Variable* `character_set_server' *Variable Name* `character_set_server' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `string' The server's default character set. * `character_set_system' Options for character_set_system *Variable Name* `character_set_system' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `string' The character set used by the server for storing identifiers. The value is always `utf8'. * `character_sets_dir' Options for character-sets-dir *Command-Line `--character-sets-dir=path' Format* *Option-File Format* `character-sets-dir=path' *Option Sets Yes, Variable* `character_sets_dir' *Variable Name* `character-sets-dir' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `directory name' The directory where character sets are installed. * `collation_connection' Options for collation_connection *Variable Name* `collation_connection' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `string' The collation of the connection character set. * `collation_database' Options for collation_database *Variable Name* `collation_database' *Variable Scope* Global, Session *Dynamic Variable* Yes *Footnote* This option is dynamic, but only the server should set this information. You should not set the value of this variable manually. *Permitted Values * *Type* `string' The collation used by the default database. The server sets this variable whenever the default database changes. If there is no default database, the variable has the same value as `collation_server'. * `collation_server' Options for collation-server *Command-Line `--collation-server' Format* *Option-File Format* `collation-server' *Option Sets Yes, Variable* `collation_server' *Variable Name* `collation_server' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `string' The server's default collation. * `completion_type' Options for completion_type *Command-Line `--completion_type=#' Format* *Option-File Format* `completion_type' *Option Sets Yes, Variable* `completion_type' *Variable Name* `completion_type' *Variable Scope* Global, Session *Dynamic Variable* Yes The transaction completion type. This variable can take the values shown in the following table. Value Description 0 *Note `COMMIT': commit. and *Note `ROLLBACK': commit. are unaffected. This is the default value. 1 *Note `COMMIT': commit. and *Note `ROLLBACK': commit. are equivalent to `COMMIT AND CHAIN' and `ROLLBACK AND CHAIN', respectively. (A new transaction starts immediately with the same isolation level as the just-terminated transaction.) 2 *Note `COMMIT': commit. and *Note `ROLLBACK': commit. are equivalent to `COMMIT RELEASE' and `ROLLBACK RELEASE', respectively. (The server disconnects after terminating the transaction.) `completion_type' affects transactions that begin with *Note `START TRANSACTION': commit. or *Note `BEGIN': commit. and end with *Note `COMMIT': commit. or *Note `ROLLBACK': commit. It does not apply to implicit commits resulting from execution of the statements listed in *Note implicit-commit::. It also does not apply for *Note `XA COMMIT': xa-statements, *Note `XA ROLLBACK': xa-statements, or when `autocommit=1'. * `concurrent_insert' Options for concurrent_insert *Command-Line `--concurrent_insert[=#]' Format* *Option-File Format* `concurrent_insert' *Option Sets Yes, Variable* `concurrent_insert' *Variable Name* `concurrent_insert' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `boolean' *Default* `TRUE' If 1 (the default), MySQL permits *Note `INSERT': insert. and *Note `SELECT': select. statements to run concurrently for `MyISAM' tables that have no free blocks in the middle of the data file. If you start *Note `mysqld': mysqld. with `--skip-new', this variable is set to 0. This variable can take three integer values. Value Description 0 Disables concurrent inserts 1 (Default) Enables concurrent insert for `MyISAM' tables that do not have holes 2 Enables concurrent inserts for all `MyISAM' tables, even those that have holes. For a table with a hole, new rows are inserted at the end of the table if it is in use by another thread. Otherwise, MySQL acquires a normal write lock and inserts the row into the hole. See also *Note concurrent-inserts::. * `connect_timeout' Options for connect_timeout *Command-Line `--connect_timeout=#' Format* *Option-File Format* `connect_timeout' *Option Sets Yes, Variable* `connect_timeout' *Variable Name* `connect_timeout' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values (<= 5.1.22)* *Type* `numeric' *Default* `5' *Permitted Values (>= 5.1.23)* *Type* `numeric' *Default* `10' The number of seconds that the *Note `mysqld': mysqld. server waits for a connect packet before responding with `Bad handshake'. The default value is 10 seconds as of MySQL 5.1.23 and 5 seconds before that. Increasing the `connect_timeout' value might help if clients frequently encounter errors of the form `Lost connection to MySQL server at 'XXX', system error: ERRNO'. * `datadir' Options for datadir *Command-Line `--datadir=path' Format* ** `-h' *Option-File Format* `datadir' *Option Sets Yes, Variable* `datadir' *Variable Name* `datadir' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `file name' The MySQL data directory. This variable can be set with the `--datadir' option. * `date_format' This variable is unused. * `datetime_format' This variable is unused. * `debug' Options for debug *Command-Line `--debug[=debug_options]' Format* *Option-File Format* `debug' *Variable Name* `debug' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `string' *Default* `'d:t:o,/tmp/mysqld.trace'' This variable indicates the current debugging settings. It is available only for servers built with debugging support. The initial value comes from the value of instances of the `--debug' option given at server startup. The global and session values may be set at runtime; the `SUPER' privilege is required, even for the session value. Assigning a value that begins with `+' or `-' cause the value to added to or subtracted from the current value: mysql> SET debug = 'T'; mysql> SELECT @@debug; +---------+ | @@debug | +---------+ | T | +---------+ mysql> SET debug = '+P'; mysql> SELECT @@debug; +---------+ | @@debug | +---------+ | P:T | +---------+ mysql> SET debug = '-P'; mysql> SELECT @@debug; +---------+ | @@debug | +---------+ | T | +---------+ This variable was added in MySQL 5.1.7. * `debug_sync' Options for debug_sync *Version Introduced* 5.1.41 *Variable Name* `debug_sync' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `string' This variable is the user interface to the Debug Sync facility. Use of Debug Sync requires that MySQL be configured with the `--enable-debug-sync' option (see *Note source-configuration-options::). If Debug Sync is not compiled in, this system variable is not available. The global variable value is read only and indicates whether the facility is enabled. By default, Debug Sync is disabled and the value of `debug_sync' is `OFF'. If the server is started with `--debug-sync-timeout=N', where N is a timeout value greater than 0, Debug Sync is enabled and the value of `debug_sync' is `ON - current signal' followed by the signal name. Also, N becomes the default timeout for individual synchronization points. The session value can be read by any user and will have the same value as the global variable. The session value can be set by users that have the `SUPER' privilege to control synchronization points. For a description of the Debug Sync facility and how to use synchronization points, see MySQL Internals: Test Synchronization (http://forge.mysql.com/wiki/MySQL_Internals_Test_Synchronization). This variable was added in MySQL 5.1.41. * `default_week_format' Options for default_week_format *Command-Line `--default_week_format=#' Format* *Option-File Format* `default_week_format' *Option Sets Yes, Variable* `default_week_format' *Variable Name* `default_week_format' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `numeric' *Default* `0' *Range* `0-7' The default mode value to use for the `WEEK()' function. See *Note date-and-time-functions::. * `delay_key_write' Options for delay-key-write *Command-Line `--delay-key-write[=name]' Format* *Option-File Format* `delay-key-write' *Option Sets Yes, Variable* `delay_key_write' *Variable Name* `delay-key-write' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `enumeration' *Default* `ON' *Valid Values* `ON' `OFF' `ALL' This option applies only to `MyISAM' tables. It can have one of the following values to affect handling of the `DELAY_KEY_WRITE' table option that can be used in *Note `CREATE TABLE': create-table. statements. Option Description `OFF' `DELAY_KEY_WRITE' is ignored. `ON' MySQL honors any `DELAY_KEY_WRITE' option specified in *Note `CREATE TABLE': create-table. statements. This is the default value. `ALL' All new opened tables are treated as if they were created with the `DELAY_KEY_WRITE' option enabled. If `DELAY_KEY_WRITE' is enabled for a table, the key buffer is not flushed for the table on every index update, but only when the table is closed. This speeds up writes on keys a lot, but if you use this feature, you should add automatic checking of all `MyISAM' tables by starting the server with the `--myisam-recover' option (for example, `--myisam-recover=BACKUP,FORCE'). See *Note server-options::, and *Note myisam-start::. *Warning*: If you enable external locking with `--external-locking', there is no protection against index corruption for tables that use delayed key writes. * `delayed_insert_limit' Options for delayed_insert_limit *Command-Line `--delayed_insert_limit=#' Format* *Option-File Format* `delayed_insert_limit' *Option Sets Yes, Variable* `delayed_insert_limit' *Variable Name* `delayed_insert_limit' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Platform Bit Size* `32' *Type* `numeric' *Default* `100' *Range* `1-4294967295' *Permitted Values * *Platform Bit Size* `64' *Type* `numeric' *Default* `100' *Range* `1-18446744073709547520' After inserting `delayed_insert_limit' delayed rows, the *Note `INSERT DELAYED': insert-delayed. handler thread checks whether there are any *Note `SELECT': select. statements pending. If so, it permits them to execute before continuing to insert delayed rows. * `delayed_insert_timeout' Options for delayed_insert_timeout *Command-Line `--delayed_insert_timeout=#' Format* *Option-File Format* `delayed_insert_timeout' *Option Sets Yes, Variable* `delayed_insert_timeout' *Variable Name* `delayed_insert_timeout' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `numeric' *Default* `300' How many seconds an *Note `INSERT DELAYED': insert-delayed. handler thread should wait for *Note `INSERT': insert. statements before terminating. * `delayed_queue_size' Options for delayed_queue_size *Command-Line `--delayed_queue_size=#' Format* *Option-File Format* `delayed_queue_size' *Option Sets Yes, Variable* `delayed_queue_size' *Variable Name* `delayed_queue_size' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Platform Bit Size* `32' *Type* `numeric' *Default* `1000' *Range* `1-4294967295' *Permitted Values * *Platform Bit Size* `64' *Type* `numeric' *Default* `1000' *Range* `1-18446744073709547520' This is a per-table limit on the number of rows to queue when handling *Note `INSERT DELAYED': insert-delayed. statements. If the queue becomes full, any client that issues an *Note `INSERT DELAYED': insert-delayed. statement waits until there is room in the queue again. * `div_precision_increment' Options for div_precision_increment *Command-Line `--div_precision_increment=#' Format* *Option-File Format* `div_precision_increment' *Option Sets Yes, Variable* `div_precision_increment' *Variable Name* `div_precision_increment' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `numeric' *Default* `4' *Range* `0-30' This variable indicates the number of digits by which to increase the scale of the result of division operations performed with the `/' operator. The default value is 4. The minimum and maximum values are 0 and 30, respectively. The following example illustrates the effect of increasing the default value. mysql> SELECT 1/7; +--------+ | 1/7 | +--------+ | 0.1429 | +--------+ mysql> SET div_precision_increment = 12; mysql> SELECT 1/7; +----------------+ | 1/7 | +----------------+ | 0.142857142857 | +----------------+ * `engine_condition_pushdown' Options for engine-condition-pushdown *Command-Line `--engine-condition-pushdown' Format* *Option-File Format* `engine-condition-pushdown' *Option Sets Yes, Variable* `engine_condition_pushdown' *Variable Name* `engine_condition_pushdown' *Variable Scope* Global, Session *Dynamic Variable* Yes *Deprecated* 5.5.3, by `optimizer_switch' *Permitted Values (>= 5.1.0)* *Type* `boolean' *Default* `ON' The engine condition pushdown optimization enables processing for certain comparisons to be `pushed down' to the storage engine level for more efficient execution. For more information, see *Note condition-pushdown-optimization::. Engine condition pushdown is used only by the *Note `NDBCLUSTER': mysql-cluster. storage engine. Enabling this optimization on a MySQL Server acting as a MySQL Cluster SQL node causes `WHERE' conditions on unindexed columns to be evaluated on the cluster's data nodes and only the rows that match to be sent back to the SQL node that issued the query. This greatly reduces the amount of cluster data that must be sent over the network, increasing the efficiency with which results are returned. The `engine_condition_pushdown' variable controls whether engine condition pushdown is enabled. By default, this variable is `ON' (1). Setting it to `OFF' (0) disables pushdown. * `error_count' The number of errors that resulted from the last statement that generated messages. This variable is read only. See *Note show-errors::. * `event_scheduler' Options for event-scheduler *Version Introduced* 5.1.6 *Command-Line `--event-scheduler[=value]' Format* *Option-File Format* `event-scheduler' *Option Sets Yes, Variable* `event_scheduler' *Variable Name* `event_scheduler' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `enumeration' *Default* `OFF' *Valid Values* `ON' `OFF' `DISABLED' This variable indicates the status of the Event Scheduler; as of MySQL 5.1.12, possible values are `ON', `OFF', and `DISABLED', with the default being `OFF'. This variable and its effects on the Event Scheduler's operation are discussed in greater detail in the Overview section of the Events chapter. This variable was added in MySQL 5.1.6. * `expire_logs_days' Options for expire_logs_days *Command-Line `--expire_logs_days=#' Format* *Option-File Format* `expire_logs_days' *Option Sets Yes, Variable* `expire_logs_days' *Variable Name* `expire_logs_days' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `numeric' *Default* `0' *Range* `0-99' The number of days for automatic binary log file removal. The default is 0, which means `no automatic removal.' Possible removals happen at startup and when the binary log is flushed. Log flushing occurs as indicated in *Note server-logs::. To remove binary log files manually, use the *Note `PURGE BINARY LOGS': purge-binary-logs. statement. See *Note purge-binary-logs::. * `flush' Options for flush *Command-Line `--flush' Format* *Option-File Format* `flush' *Variable Name* `flush' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `boolean' *Default* `OFF' If `ON', the server flushes (synchronizes) all changes to disk after each SQL statement. Normally, MySQL does a write of all changes to disk only after each SQL statement and lets the operating system handle the synchronizing to disk. See *Note crashing::. This variable is set to `ON' if you start *Note `mysqld': mysqld. with the `--flush' option. * `flush_time' Options for flush_time *Command-Line `--flush_time=#' Format* *Option-File Format* `flush_time' *Option Sets Yes, Variable* `flush_time' *Variable Name* `flush_time' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `numeric' *Default* `0' *Min Value* `0' *Permitted Values * *Type* (windows) `numeric' *Default* `1800' *Min Value* `0' If this is set to a nonzero value, all tables are closed every `flush_time' seconds to free up resources and synchronize unflushed data to disk. This option is best used only on Windows 9x or Me, or on systems with minimal resources. * `foreign_key_checks' If set to 1 (the default), foreign key constraints for `InnoDB' tables are checked. If set to 0, they are ignored. Disabling foreign key checking can be useful for reloading `InnoDB' tables in an order different from that required by their parent/child relationships. See *Note innodb-foreign-key-constraints::. Setting `foreign_key_checks' to 0 also affects data definition statements: *Note `DROP SCHEMA': drop-database. drops a schema even if it contains tables that have foreign keys that are referred to by tables outside the schema, and *Note `DROP TABLE': drop-table. drops tables that have foreign keys that are referred to by other tables. *Note*: Setting `foreign_key_checks' to 1 does not trigger a scan of the existing table data. Therefore, rows added to the table while `foreign_key_checks = 0' will not be verified for consistency. * `ft_boolean_syntax' Options for ft_boolean_syntax *Command-Line `--ft_boolean_syntax=name' Format* *Option-File Format* `ft_boolean_syntax' *Variable Name* `ft_boolean_syntax' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `string' *Default* `+-><()~*:""&' The list of operators supported by boolean full-text searches performed using `IN BOOLEAN MODE'. See *Note fulltext-boolean::. The default variable value is `'+ -><()~*:""&|''. The rules for changing the value are as follows: * Operator function is determined by position within the string. * The replacement value must be 14 characters. * Each character must be an ASCII nonalphanumeric character. * Either the first or second character must be a space. * No duplicates are permitted except the phrase quoting operators in positions 11 and 12. These two characters are not required to be the same, but they are the only two that may be. * Positions 10, 13, and 14 (which by default are set to ``:'', ``&'', and ``|'') are reserved for future extensions. * `ft_max_word_len' Options for ft_max_word_len *Command-Line `--ft_max_word_len=#' Format* *Option-File Format* `ft_max_word_len' *Option Sets Yes, Variable* `ft_max_word_len' *Variable Name* `ft_max_word_len' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `numeric' *Min Value* `10' The maximum length of the word to be included in a `FULLTEXT' index. *Note*: `FULLTEXT' indexes must be rebuilt after changing this variable. Use `REPAIR TABLE TBL_NAME QUICK'. * `ft_min_word_len' Options for ft_min_word_len *Command-Line `--ft_min_word_len=#' Format* *Option-File Format* `ft_min_word_len' *Option Sets Yes, Variable* `ft_min_word_len' *Variable Name* `ft_min_word_len' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `numeric' *Default* `4' *Min Value* `1' The minimum length of the word to be included in a `FULLTEXT' index. *Note*: `FULLTEXT' indexes must be rebuilt after changing this variable. Use `REPAIR TABLE TBL_NAME QUICK'. * `ft_query_expansion_limit' Options for ft_query_expansion_limit *Command-Line `--ft_query_expansion_limit=#' Format* *Option-File Format* `ft_query_expansion_limit' *Option Sets Yes, Variable* `ft_query_expansion_limit' *Variable Name* `ft_query_expansion_limit' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `numeric' *Default* `20' *Range* `0-1000' The number of top matches to use for full-text searches performed using `WITH QUERY EXPANSION'. * `ft_stopword_file' Options for ft_stopword_file *Command-Line `--ft_stopword_file=file_name' Format* *Option-File Format* `ft_stopword_file=file_name' *Option Sets Yes, Variable* `ft_stopword_file' *Variable Name* `ft_stopword_file' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `file name' The file from which to read the list of stopwords for full-text searches. The server looks for the file in the data directory unless an absolute path name is given to specify a different directory. All the words from the file are used; comments are _not_ honored. By default, a built-in list of stopwords is used (as defined in the `storage/myisam/ft_static.c' file). Setting this variable to the empty string (`''') disables stopword filtering. See also *Note fulltext-stopwords::. *Note*: `FULLTEXT' indexes must be rebuilt after changing this variable or the contents of the stopword file. Use `REPAIR TABLE TBL_NAME QUICK'. * `general_log' Options for general-log *Version Introduced* 5.1.12 *Command-Line `--general-log' Format* *Option-File Format* `general-log' *Option Sets Yes, Variable* `general_log' *Variable Name* `general_log' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `boolean' *Default* `OFF' Whether the general query log is enabled. The value can be 0 (or `OFF') to disable the log or 1 (or `ON') to enable the log. The default value depends on whether the `--general_log' option is given (`--log' before MySQL 5.1.29). The destination for log output is controlled by the `log_output' system variable; if that value is `NONE', no log entries are written even if the log is enabled. The `general_log' variable was added in MySQL 5.1.12. * `general_log_file' Options for general_log_file *Version Introduced* 5.1.12 *Command-Line `--general-log-file=file_name'5.1.29 Format* *Option-File Format* `general_log_file'5.1.29 *Option Sets Yes, Variable* `general_log_file' *Variable Name* `general_log_file' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `file name' *Default* `host_name.log' The name of the general query log file. The default value is `HOST_NAME.log', but the initial value can be changed with the `--general_log_file' option (`--log' before MySQL 5.1.29). This variable was added in MySQL 5.1.12. * `group_concat_max_len' Options for group_concat_max_len *Command-Line `--group_concat_max_len=#' Format* *Option-File Format* `group_concat_max_len' *Option Sets Yes, Variable* `group_concat_max_len' *Variable Name* `group_concat_max_len' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Platform Bit Size* `32' *Type* `numeric' *Default* `1024' *Range* `4-4294967295' *Permitted Values * *Platform Bit Size* `64' *Type* `numeric' *Default* `1024' *Range* `4-18446744073709547520' The maximum permitted result length in bytes for the `GROUP_CONCAT()' function. The default is 1024. * `have_archive' `YES' if *Note `mysqld': mysqld. supports `ARCHIVE' tables, `NO' if not. This variable was removed in MySQL 5.1.14. * `have_blackhole_engine' `YES' if *Note `mysqld': mysqld. supports `BLACKHOLE' tables, `NO' if not. This variable was removed in MySQL 5.1.14. * `have_compress' `YES' if the `zlib' compression library is available to the server, `NO' if not. If not, the `COMPRESS()' and `UNCOMPRESS()' functions cannot be used. * `have_community_features' `YES' if statement profiling is enabled, `NO' if not. See *Note show-profile::. This variable is renamed to `have_profiling' in MySQL 5.5. * `have_crypt' `YES' if the `crypt()' system call is available to the server, `NO' if not. If not, the `ENCRYPT()' function cannot be used. * `have_csv' `YES' if *Note `mysqld': mysqld. supports `CSV' tables, `NO' if not. This variable is deprecated and is removed in MySQL 5.6. Use *Note `SHOW ENGINES': show-engines. instead. * `have_dynamic_loading' `YES' if *Note `mysqld': mysqld. supports dynamic loading of plugins, `NO' if not. This variable was added in MySQL 5.1.10. * `have_example_engine' `YES' if *Note `mysqld': mysqld. supports `EXAMPLE' tables, `NO' if not. This variable was removed in MySQL 5.1.14. * `have_federated_engine' `YES' if *Note `mysqld': mysqld. supports `FEDERATED' tables, `NO' if not. This variable was removed in MySQL 5.1.14. * `have_geometry' `YES' if the server supports spatial data types, `NO' if not. * `have_innodb' `YES' if *Note `mysqld': mysqld. supports `InnoDB' tables. `DISABLED' if `--skip-innodb' is used. This variable is deprecated and is removed in MySQL 5.6. Use *Note `SHOW ENGINES': show-engines. instead. * `have_isam' In MySQL 5.1, this variable appears only for reasons of backward compatibility. It is always `NO' because `ISAM' tables are no longer supported. This variable was removed in MySQL 5.1.7. * `have_merge_engine' `YES' if *Note `mysqld': mysqld. supports `MERGE' tables. `DISABLED' if `--skip-merge' is used. This variable was removed in MySQL 5.1.3. * `have_openssl' `YES' if *Note `mysqld': mysqld. supports SSL connections, `NO' if not. As of MySQL 5.1.17, this variable is an alias for `have_ssl'. * `have_partitioning' `YES' if *Note `mysqld': mysqld. supports partitioning. Added in MySQL 5.1.1 as `have_partition_engine' and renamed to `have_partioning' in 5.1.6. This variable is deprecated and is removed in MySQL 5.6. Use *Note `SHOW ENGINES': show-engines. instead. * `have_query_cache' `YES' if *Note `mysqld': mysqld. supports the query cache, `NO' if not. * `have_row_based_replication' Options for have_row_based_replication *Version Introduced* 5.1.5 *Version Removed* 5.1.15 *Variable Name* `have_row_based_replication' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `boolean' `YES' if the server can perform replication using row-based binary logging. If the value is `NO', the server can use only statement-based logging. See *Note replication-formats::. This variable was added in MySQL 5.1.5 and removed in 5.1.15. * `have_raid' In MySQL 5.1, this variable appears only for reasons of backward compatibility. It is always `NO' because `RAID' tables are no longer supported. This variable was removed in MySQL 5.1.7. * `have_rtree_keys' `YES' if `RTREE' indexes are available, `NO' if not. (These are used for spatial indexes in `MyISAM' tables.) * `have_ssl' `YES' if *Note `mysqld': mysqld. supports SSL connections, `NO' if not. `DISABLED' indicates that the server was compiled with SSL support, but but was not started with the appropriate `--ssl-XXX' options. See *Note secure-using-ssl::, for more information. This variable was added in MySQL 5.1.17. Before that, use `have_openssl'. * `have_symlink' `YES' if symbolic link support is enabled, `NO' if not. This is required on Unix for support of the `DATA DIRECTORY' and `INDEX DIRECTORY' table options, and on Windows for support of data directory symlinks. * `hostname' Options for hostname *Version Introduced* 5.1.17 *Variable Name* `hostname' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `string' The server sets this variable to the server host name at startup. This variable was added in MySQL 5.1.17. * `identity' This variable is a synonym for the `last_insert_id' variable. It exists for compatibility with other database systems. You can read its value with `SELECT @@identity', and set it using `SET identity'. * `init_connect' Options for init_connect *Command-Line `--init-connect=name' Format* *Option-File Format* `init_connect' *Option Sets Yes, Variable* `init_connect' *Variable Name* `init_connect' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `string' A string to be executed by the server for each client that connects. The string consists of one or more SQL statements, separated by semicolon characters. For example, each client session begins by default with autocommit mode enabled. There is no global `autocommit' system variable to specify that autocommit should be disabled by default, but `init_connect' can be used to achieve the same effect: SET GLOBAL init_connect='SET autocommit=0'; The `init_connect' variable can also be set on the command line or in an option file. To set the variable as just shown using an option file, include these lines: [mysqld] init_connect='SET autocommit=0' The content of `init_connect' is not executed for users that have the `SUPER' privilege. This is done so that an erroneous value for `init_connect' does not prevent all clients from connecting. For example, the value might contain a statement that has a syntax error, thus causing client connections to fail. Not executing `init_connect' for users that have the `SUPER' privilege enables them to open a connection and fix the `init_connect' value. * `init_file' Options for init-file *Command-Line `--init-file=file_name' Format* *Option-File Format* `init-file=file_name' *Option Sets Yes, Variable* `init_file' *Variable Name* `init_file' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `file name' The name of the file specified with the `--init-file' option when you start the server. This should be a file containing SQL statements that you want the server to execute when it starts. Each statement must be on a single line and should not include comments. No statement terminator such as `;', `\g', or `\G' should be given at the end of each statement. Note that the `--init-file' option is unavailable if MySQL was configured with the `--disable-grant-options' option. See *Note source-configuration-options::. * `innodb_XXX' `InnoDB' system variables are listed in *Note innodb-parameters::. * `insert_id' The value to be used by the following *Note `INSERT': insert. or *Note `ALTER TABLE': alter-table. statement when inserting an `AUTO_INCREMENT' value. This is mainly used with the binary log. * `interactive_timeout' Options for interactive_timeout *Command-Line `--interactive_timeout=#' Format* *Option-File Format* `interactive_timeout' *Option Sets Yes, Variable* `interactive_timeout' *Variable Name* `interactive_timeout' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `numeric' *Default* `28800' *Min Value* `1' The number of seconds the server waits for activity on an interactive connection before closing it. An interactive client is defined as a client that uses the `CLIENT_INTERACTIVE' option to *Note `mysql_real_connect()': mysql-real-connect. See also `wait_timeout'. * `join_buffer_size' Options for join_buffer_size *Command-Line `--join_buffer_size=#' Format* *Option-File Format* `join_buffer_size' *Option Sets Yes, Variable* `join_buffer_size' *Variable Name* `join_buffer_size' *Variable Scope* Global, Session *Dynamic Variable* Yes The minimum size of the buffer that is used for plain index scans, range index scans, and joins that do not use indexes and thus perform full table scans. Normally, the best way to get fast joins is to add indexes. Increase the value of `join_buffer_size' to get a faster full join when adding indexes is not possible. One join buffer is allocated for each full join between two tables. For a complex join between several tables for which indexes are not used, multiple join buffers might be necessary. There is no gain from setting the buffer larger than required to hold each matching row, and all joins allocate at least the minimum size, so use caution in setting this variable to a large value globally. It is better to keep the global setting small and change to a larger setting only in sessions that are doing large joins. Memory allocation time can cause substantial performance drops if the global size is larger than needed by most queries that use it. The maximum permissible setting for `join_buffer_size' is 4GB. As of MySQL 5.1.23, values larger than 4GB are permitted for 64-bit platforms (except 64-bit Windows, for which large values are truncated to 4GB with a warning). * `keep_files_on_create' Options for keep_files_on_create *Version Introduced* 5.1.21 *Command-Line `--keep_files_on_create=#' Format* *Option-File Format* `keep_files_on_create' *Option Sets Yes, Variable* `keep_files_on_create' *Variable Name* `keep_files_on_create' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `boolean' *Default* `OFF' If a `MyISAM' table is created with no `DATA DIRECTORY' option, the `.MYD' file is created in the database directory. By default, if `MyISAM' finds an existing `.MYD' file in this case, it overwrites it. The same applies to `.MYI' files for tables created with no `INDEX DIRECTORY' option. To suppress this behavior, set the `keep_files_on_create' variable to `ON' (1), in which case `MyISAM' will not overwrite existing files and returns an error instead. The default value is `OFF' (0). If a `MyISAM' table is created with a `DATA DIRECTORY' or `INDEX DIRECTORY' option and an existing `.MYD' or `.MYI' file is found, MyISAM always returns an error. It will not overwrite a file in the specified directory. This variable was added in MySQL 5.1.23. * `key_buffer_size' Options for key_buffer_size *Command-Line `--key_buffer_size=#' Format* *Option-File Format* `key_buffer_size' *Option Sets Yes, Variable* `key_buffer_size' *Variable Name* `key_buffer_size' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values (<= 5.1.22)* *Type* `numeric' *Default* `8388608' *Range* `8-4294967295' *Permitted Values (>= 5.1.23)* *Platform Bit Size* `32' *Type* `numeric' *Default* `8388608' *Range* `8-4294967295' *Permitted Values (>= 5.1.23)* *Platform Bit Size* `64' *Type* `numeric' *Default* `8388608' *Range* `8-OS_PER_PROCESS_LIMIT' Index blocks for `MyISAM' tables are buffered and are shared by all threads. `key_buffer_size' is the size of the buffer used for index blocks. The key buffer is also known as the key cache. The maximum permissible setting for `key_buffer_size' is 4GB on 32-bit platforms. As of MySQL 5.1.23, values larger than 4GB are permitted for 64-bit platforms, except 64-bit Windows prior to MySQL 5.1.31, for which large values are truncated to 4GB with a warning. As of MySQL 5.1.31, values larger than 4GB are also permitted for 64-bit Windows. The effective maximum size might be less, depending on your available physical RAM and per-process RAM limits imposed by your operating system or hardware platform. The value of this variable indicates the amount of memory requested. Internally, the server allocates as much memory as possible up to this amount, but the actual allocation might be less. You can increase the value to get better index handling for all reads and multiple writes; on a system whose primary function is to run MySQL using the *Note `MyISAM': myisam-storage-engine. storage engine, 25% of the machine's total memory is an acceptable value for this variable. However, you should be aware that, if you make the value too large (for example, more than 50% of the machine's total memory), your system might start to page and become extremely slow. This is because MySQL relies on the operating system to perform file system caching for data reads, so you must leave some room for the file system cache. You should also consider the memory requirements of any other storage engines that you may be using in addition to *Note `MyISAM': myisam-storage-engine. For even more speed when writing many rows at the same time, use *Note `LOCK TABLES': lock-tables. See *Note insert-speed::. You can check the performance of the key buffer by issuing a *Note `SHOW STATUS': show-status. statement and examining the `Key_read_requests', `Key_reads', `Key_write_requests', and `Key_writes' status variables. (See *Note show::.) The `Key_reads/Key_read_requests' ratio should normally be less than 0.01. The `Key_writes/Key_write_requests' ratio is usually near 1 if you are using mostly updates and deletes, but might be much smaller if you tend to do updates that affect many rows at the same time or if you are using the `DELAY_KEY_WRITE' table option. The fraction of the key buffer in use can be determined using `key_buffer_size' in conjunction with the `Key_blocks_unused' status variable and the buffer block size, which is available from the `key_cache_block_size' system variable: 1 - ((Key_blocks_unused * key_cache_block_size) / key_buffer_size) This value is an approximation because some space in the key buffer is allocated internally for administrative structures. Factors that influence the amount of overhead for these structures include block size and pointer size. As block size increases, the percentage of the key buffer lost to overhead tends to decrease. Larger blocks results in a smaller number of read operations (because more keys are obtained per read), but conversely an increase in reads of keys that are not examined (if not all keys in a block are relevant to a query). It is possible to create multiple `MyISAM' key caches. The size limit of 4GB applies to each cache individually, not as a group. See *Note myisam-key-cache::. * `key_cache_age_threshold' Options for key_cache_age_threshold *Command-Line `--key_cache_age_threshold=#' Format* *Option-File Format* `key_cache_age_threshold' *Option Sets Yes, Variable* `key_cache_age_threshold' *Variable Name* `key_cache_age_threshold' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Platform Bit Size* `32' *Type* `numeric' *Default* `300' *Range* `100-4294967295' *Permitted Values * *Platform Bit Size* `64' *Type* `numeric' *Default* `300' *Range* `100-18446744073709547520' This value controls the demotion of buffers from the hot sublist of a key cache to the warm sublist. Lower values cause demotion to happen more quickly. The minimum value is 100. The default value is 300. See *Note myisam-key-cache::. * `key_cache_block_size' Options for key_cache_block_size *Command-Line `--key_cache_block_size=#' Format* *Option-File Format* `key_cache_block_size' *Option Sets Yes, Variable* `key_cache_block_size' *Variable Name* `key_cache_block_size' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `numeric' *Default* `1024' *Range* `512-16384' The size in bytes of blocks in the key cache. The default value is 1024. See *Note myisam-key-cache::. * `key_cache_division_limit' Options for key_cache_division_limit *Command-Line `--key_cache_division_limit=#' Format* *Option-File Format* `key_cache_division_limit' *Option Sets Yes, Variable* `key_cache_division_limit' *Variable Name* `key_cache_division_limit' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `numeric' *Default* `100' *Range* `1-100' The division point between the hot and warm sublists of the key cache buffer list. The value is the percentage of the buffer list to use for the warm sublist. Permissible values range from 1 to 100. The default value is 100. See *Note myisam-key-cache::. * `language' Options for language *Command-Line `--language=name' Format* ** `-L' *Option-File Format* `language' *Option Sets Yes, Variable* `language' *Variable Name* `language' *Variable Scope* Global *Dynamic Variable* No *Deprecated* 5.5.0, by `lc-messages-dir' *Permitted Values * *Type* `directory name' *Default* `/usr/local/mysql/share/mysql/english/' The directory where error messages are located. See *Note error-message-language::. * `large_files_support' Options for large_files_support *Variable Name* `large_files_support' *Variable Scope* Global *Dynamic Variable* No Whether *Note `mysqld': mysqld. was compiled with options for large file support. * `large_pages' Options for large-pages *Command-Line `--large-pages' Format* *Option-File Format* `large-pages' *Option Sets Yes, Variable* `large_pages' *Variable Name* `large_pages' *Variable Scope* Global *Dynamic Variable* No *Platform Specific* linux *Permitted Values * *Type* (linux) `boolean' *Default* `FALSE' Whether large page support is enabled (via the `--large-pages' option). See *Note large-page-support::. * `large_page_size' Options for large_page_size *Variable Name* `large_page_size' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* (linux) `numeric' *Default* `0' If large page support is enabled, this shows the size of memory pages. Currently, large memory pages are supported only on Linux; on other platforms, the value of this variable is always 0. See *Note large-page-support::. * `last_insert_id' The value to be returned from `LAST_INSERT_ID()'. This is stored in the binary log when you use `LAST_INSERT_ID()' in a statement that updates a table. Setting this variable does not update the value returned by the *Note `mysql_insert_id()': mysql-insert-id. C API function. * `lc_time_names' Options for lc_time_names *Version Introduced* 5.1.12 *Variable Name* `lc_time_names' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `string' This variable specifies the locale that controls the language used to display day and month names and abbreviations. This variable affects the output from the `DATE_FORMAT()', `DAYNAME()' and `MONTHNAME()' functions. Locale names are POSIX-style values such as `'ja_JP'' or `'pt_BR''. The default value is `'en_US'' regardless of your system's locale setting. For further information, see *Note locale-support::. This variable was added in MySQL 5.1.12. * `license' Options for license *Variable Name* `license' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `string' *Default* `GPL' The type of license the server has. * `local_infile' Options for local_infile *Variable Name* `local_infile' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `boolean' Whether `LOCAL' is supported for *Note `LOAD DATA INFILE': load-data. statements. See *Note load-data-local::. * `locked_in_memory' Options for locked_in_memory *Variable Name* `locked_in_memory' *Variable Scope* Global *Dynamic Variable* No Whether *Note `mysqld': mysqld. was locked in memory with `--memlock'. * `log' Whether logging of all statements to the general query log is enabled. See *Note query-log::. This variable is deprecated as of MySQL 5.1.29 and is removed in MySQL 5.6. Use `general_log' instead. * `log_bin' Options for log_bin *Variable Name* `log_bin' *Variable Scope* Global *Dynamic Variable* No Whether the binary log is enabled. If the `--log-bin' option is used, then the value of this variable is `ON'; otherwise it is `OFF'. This variable reports only on the status of binary logging (enabled or disabled); it does not actually report the value to which `--log-bin' is set. See *Note binary-log::. * `log_bin_trust_function_creators' Options for log-bin-trust-function-creators *Command-Line `--log-bin-trust-function-creators' Format* *Option-File Format* `log-bin-trust-function-creators' *Option Sets Yes, Variable* `log_bin_trust_function_creators' *Variable Name* `log_bin_trust_function_creators' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `boolean' *Default* `FALSE' This variable applies when binary logging is enabled. It controls whether stored function creators can be trusted not to create stored functions that will cause unsafe events to be written to the binary log. If set to 0 (the default), users are not permitted to create or alter stored functions unless they have the `SUPER' privilege in addition to the `CREATE ROUTINE' or `ALTER ROUTINE' privilege. A setting of 0 also enforces the restriction that a function must be declared with the `DETERMINISTIC' characteristic, or with the `READS SQL DATA' or `NO SQL' characteristic. If the variable is set to 1, MySQL does not enforce these restrictions on stored function creation. This variable also applies to trigger creation. See *Note stored-programs-logging::. * `log_error' Options for log-error *Command-Line `--log-error[=name]' Format* *Option-File Format* `log-error' *Option Sets Yes, Variable* `log_error' *Variable Name* `log_error' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `file name' The location of the error log. * `log_output' Options for log-output *Version Introduced* 5.1.6 *Command-Line `--log-output[=name]' Format* *Option-File Format* `log-output' *Option Sets Yes, Variable* `log_output' *Variable Name* `log_output' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `set' *Default* `FILE' *Valid Values* `TABLE' `FILE' `NONE' The destination for general query log and slow query log output. The value can be a comma-separated list of one or more of the words `TABLE' (log to tables), `FILE' (log to files), or `NONE' (do not log to tables or files). The default value is `TABLE'. `NONE', if present, takes precedence over any other specifiers. If the value is `NONE' log entries are not written even if the logs are enabled. If the logs are not enabled, no logging occurs even if the value of `log_output' is not `NONE'. For more information, see *Note log-destinations::. This variable was added in MySQL 5.1.6. * `log_queries_not_using_indexes' Options for log-queries-not-using-indexes *Command-Line `--log-queries-not-using-indexes' Format* *Option-File Format* `log-queries-not-using-indexes' *Option Sets Yes, Variable* `log_queries_not_using_indexes' *Variable Name* `log_queries_not_using_indexes' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `boolean' Whether queries that do not use indexes are logged to the slow query log. See *Note slow-query-log::. This variable was added in MySQL 5.1.11. * `log_slave_updates' Whether updates received by a slave server from a master server should be logged to the slave's own binary log. Binary logging must be enabled on the slave for this variable to have any effect. See *Note replication-options::. * `log_slow_queries' Options for log-slow-queries *Version Deprecated* 5.1.29 *Command-Line `--log-slow-queries[=name]' Format* *Option-File Format* `log-slow-queries' *Option Sets Yes, Variable* `log_slow_queries' *Variable Name* `log_slow_queries' *Variable Scope* Global *Dynamic Variable* Yes *Deprecated* 5.1.29, by `slow-query-log' *Permitted Values * *Type* `boolean' Whether slow queries should be logged. `Slow' is determined by the value of the `long_query_time' variable. See *Note slow-query-log::. This variable is deprecated as of MySQL 5.1.29 and is removed in MySQL 5.6. Use `slow_query_log' instead. * `log_warnings' Options for log-warnings *Command-Line `--log-warnings[=#]' Format* ** `-W [#]' *Option-File Format* `log-warnings' *Option Sets Yes, Variable* `log_warnings' *Variable Name* `log_warnings' *Variable Scope* Global, Session *Dynamic Variable* Yes *Disabled by* `skip-log-warnings' *Permitted Values * *Platform Bit Size* `64' *Type* `numeric' *Default* `1' *Range* `0-18446744073709547520' Whether to produce additional warning messages. It is enabled (1) by default and can be disabled by setting it to 0. Aborted connections are not logged to the error log unless the value is greater than 1. As of MySQL 5.1.38, the server logs messages about statements that are unsafe for statement-based logging only if the value is greater than 0. * `long_query_time' Options for long_query_time *Command-Line `--long_query_time=#' Format* *Option-File Format* `long_query_time' *Option Sets Yes, Variable* `long_query_time' *Variable Name* `long_query_time' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values (>= 5.1.21)* *Type* `numeric' *Default* `10' *Min Value* `0' If a query takes longer than this many seconds, the server increments the `Slow_queries' status variable. If the slow query log is enabled, the query is logged to the slow query log file. This value is measured in real time, not CPU time, so a query that is under the threshold on a lightly loaded system might be above the threshold on a heavily loaded one. Prior to MySQL 5.1.21, the minimum value is 1, and the value for this variable must be an integer. Beginning with MySQL 5.1.21, the minimum is 0, and a resolution of microseconds is supported when logging to a file. However, the microseconds part is ignored and only integer values are written when logging to tables. The default value is 10. See *Note slow-query-log::. * `low_priority_updates' Options for low-priority-updates *Command-Line `--low-priority-updates' Format* *Option-File Format* `low-priority-updates' *Option Sets Yes, Variable* `low_priority_updates' *Variable Name* `low_priority_updates' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `boolean' *Default* `FALSE' If set to `1', all *Note `INSERT': insert, *Note `UPDATE': update, *Note `DELETE': delete, and `LOCK TABLE WRITE' statements wait until there is no pending *Note `SELECT': select. or `LOCK TABLE READ' on the affected table. This affects only storage engines that use only table-level locking (such as `MyISAM', `MEMORY', and `MERGE'). This variable previously was named `sql_low_priority_updates'. * `lower_case_file_system' Options for lower_case_file_system *Command-Line `--lower_case_file_system[=#]' Format* *Option-File Format* `lower_case_file_system' *Option Sets Yes, Variable* `lower_case_file_system' *Variable Name* `lower_case_file_system' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `boolean' This variable describes the case sensitivity of file names on the file system where the data directory is located. `OFF' means file names are case sensitive, `ON' means they are not case sensitive. This variable is read only because it reflects a file system attribute and setting it would have no effect on the file system. * `lower_case_table_names' Options for lower_case_table_names *Command-Line `--lower_case_table_names[=#]' Format* *Option-File Format* `lower_case_table_names' *Option Sets Yes, Variable* `lower_case_table_names' *Variable Name* `lower_case_table_names' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `numeric' *Default* `0' *Range* `0-2' If set to 0, table names are stored as specified and comparisons are case sensitive. If set to 1, table names are stored in lowercase on disk and comparisons are not case sensitive. If set to 2, table names are stored as given but compared in lowercase. This option also applies to database names and table aliases. For additional information, see *Note identifier-case-sensitivity::. You should _not_ set this variable to 0 if you are running MySQL on a system that has case-insensitive file names (such as Windows or Mac OS X). If you set this variable to 0 on such a system and access `MyISAM' tablenames using different lettercases, index corruption may result. On Windows the default value is 1. On Mac OS X, the default value is 2. If you are using `InnoDB' tables, you should set this variable to 1 on all platforms to force names to be converted to lowercase. Prior to MySQL Cluster NDB 6.3.35, MySQL Cluster NDB 7.0.15, and MySQL Cluster NDB 7.1.4, this is also true for tables using the `NDB' storage engine. The setting of this variable has no effect on replication filtering options. See *Note replication-rules::, for more information. You should not use different settings for `lower_case_table_names' on replication masters and slaves. In particular, you should not do this when the slave uses a case-sensitive file system, as this can cause replication to fail. For more information, see *Note replication-features-variables::. * `max_allowed_packet' Options for max_allowed_packet *Command-Line `--max_allowed_packet=#' Format* *Option-File Format* `max_allowed_packet' *Option Sets Yes, Variable* `max_allowed_packet' *Variable Name* `max_allowed_packet' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `numeric' *Default* `1048576' *Range* `1024-1073741824' The maximum size of one packet or any generated/intermediate string. The packet message buffer is initialized to `net_buffer_length' bytes, but can grow up to `max_allowed_packet' bytes when needed. This value by default is small, to catch large (possibly incorrect) packets. You must increase this value if you are using large *Note `BLOB': blob. columns or long strings. It should be as big as the largest *Note `BLOB': blob. you want to use. The protocol limit for `max_allowed_packet' is 1GB. The value should be a multiple of 1024; nonmultiples are rounded down to the nearest multiple. When you change the message buffer size by changing the value of the `max_allowed_packet' variable, you should also change the buffer size on the client side if your client program permits it. On the client side, `max_allowed_packet' has a default of 1GB. Some programs such as *Note `mysql': mysql. and *Note `mysqldump': mysqldump. enable you to change the client-side value by setting `max_allowed_packet' on the command line or in an option file. As of MySQL 5.1.31, the session value of this variable is read only. Before 5.1.31, setting the session value is permitted but has no effect. * `max_connect_errors' Options for max_connect_errors *Command-Line `--max_connect_errors=#' Format* *Option-File Format* `max_connect_errors' *Option Sets Yes, Variable* `max_connect_errors' *Variable Name* `max_connect_errors' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Platform Bit Size* `32' *Type* `numeric' *Default* `10' *Range* `1-4294967295' *Permitted Values * *Platform Bit Size* `64' *Type* `numeric' *Default* `10' *Range* `1-18446744073709547520' If there are more than this number of interrupted connections from a host, that host is blocked from further connections. You can unblock blocked hosts with the *Note `FLUSH HOSTS': flush. statement. If a connection is established successfully within fewer than `max_connect_errors' attempts after a previous connection was interrupted, the error count for the host is cleared to zero. However, once a host is blocked, the *Note `FLUSH HOSTS': flush. statement is the only way to unblock it. * `max_connections' Options for max_connections *Command-Line `--max_connections=#' Format* *Option-File Format* `max_connections' *Option Sets Yes, Variable* `max_connections' *Variable Name* `max_connections' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values (<= 5.1.14)* *Type* `numeric' *Default* `100' *Permitted Values (>= 5.1.15)* *Type* `numeric' *Default* `151' *Range* `1-16384' *Permitted Values (>= 5.1.17)* *Type* `numeric' *Default* `151' *Range* `1-100000' The maximum permitted number of simultaneous client connections. By default, this is 151, beginning with MySQL 5.1.15. (Previously, the default was 100.) See *Note too-many-connections::, for more information. Increasing this value increases the number of file descriptors that *Note `mysqld': mysqld. requires. See *Note table-cache::, for comments on file descriptor limits. * `max_delayed_threads' Options for max_delayed_threads *Command-Line `--max_delayed_threads=#' Format* *Option-File Format* `max_delayed_threads' *Option Sets Yes, Variable* `max_delayed_threads' *Variable Name* `max_delayed_threads' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `numeric' *Default* `20' *Range* `0-16384' Do not start more than this number of threads to handle *Note `INSERT DELAYED': insert-delayed. statements. If you try to insert data into a new table after all *Note `INSERT DELAYED': insert-delayed. threads are in use, the row is inserted as if the `DELAYED' attribute was not specified. If you set this to 0, MySQL never creates a thread to handle `DELAYED' rows; in effect, this disables `DELAYED' entirely. For the `SESSION' value of this variable, the only valid values are 0 or the `GLOBAL' value. * `max_error_count' Options for max_error_count *Command-Line `--max_error_count=#' Format* *Option-File Format* `max_error_count' *Option Sets Yes, Variable* `max_error_count' *Variable Name* `max_error_count' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `numeric' *Default* `64' *Range* `0-65535' The maximum number of error, warning, and note messages to be stored for display by the *Note `SHOW ERRORS': show-errors. and *Note `SHOW WARNINGS': show-warnings. statements. * `max_heap_table_size' Options for max_heap_table_size *Command-Line `--max_heap_table_size=#' Format* *Option-File Format* `max_heap_table_size' *Option Sets Yes, Variable* `max_heap_table_size' *Variable Name* `max_heap_table_size' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Platform Bit Size* `32' *Type* `numeric' *Default* `16777216' *Range* `16384-4294967295' *Permitted Values * *Platform Bit Size* `64' *Type* `numeric' *Default* `16777216' *Range* `16384-1844674407370954752' This variable sets the maximum size to which user-created `MEMORY' tables are permitted to grow. The value of the variable is used to calculate `MEMORY' table `MAX_ROWS' values. Setting this variable has no effect on any existing `MEMORY' table, unless the table is re-created with a statement such as *Note `CREATE TABLE': create-table. or altered with *Note `ALTER TABLE': alter-table. or *Note `TRUNCATE TABLE': truncate-table. A server restart also sets the maximum size of existing `MEMORY' tables to the global `max_heap_table_size' value. This variable is also used in conjunction with `tmp_table_size' to limit the size of internal in-memory tables. See *Note internal-temporary-tables::. * `max_insert_delayed_threads' Options for max_insert_delayed_threads *Variable Name* `max_insert_delayed_threads' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `numeric' This variable is a synonym for `max_delayed_threads'. * `max_join_size' Options for max_join_size *Command-Line `--max_join_size=#' Format* *Option-File Format* `max_join_size' *Option Sets Yes, Variable* `max_join_size' *Variable Name* `max_join_size' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `numeric' *Default* `4294967295' *Range* `1-4294967295' Do not permit *Note `SELECT': select. statements that probably need to examine more than `max_join_size' rows (for single-table statements) or row combinations (for multiple-table statements) or that are likely to do more than `max_join_size' disk seeks. By setting this value, you can catch *Note `SELECT': select. statements where keys are not used properly and that would probably take a long time. Set it if your users tend to perform joins that lack a `WHERE' clause, that take a long time, or that return millions of rows. Setting this variable to a value other than `DEFAULT' resets the value of `sql_big_selects' to `0'. If you set the `sql_big_selects' value again, the `max_join_size' variable is ignored. If a query result is in the query cache, no result size check is performed, because the result has previously been computed and it does not burden the server to send it to the client. This variable previously was named `sql_max_join_size'. * `max_length_for_sort_data' Options for max_length_for_sort_data *Command-Line `--max_length_for_sort_data=#' Format* *Option-File Format* `max_length_for_sort_data' *Option Sets Yes, Variable* `max_length_for_sort_data' *Variable Name* `max_length_for_sort_data' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `numeric' *Default* `1024' *Range* `4-8388608' The cutoff on the size of index values that determines which `filesort' algorithm to use. See *Note order-by-optimization::. * `max_long_data_size' Options for max_long_data_size *Version Introduced* 5.1.57 *Command-Line `--max_long_data_size=#' Format* *Option-File Format* `max_long_data_size' *Option Sets Yes, Variable* `max_long_data_size' *Variable Name* `max_long_data_size' *Variable Scope* Global *Dynamic Variable* No *Deprecated* 5.5.11 *Permitted Values * *Type* `numeric' *Default* `1048576' *Range* `1024-4294967295' The maximum size of parameter values that can be sent with the `mysql_stmt_send_long_data()' C API function. If not set at server startup, the default is the value of the `max_allowed_packet' system variable. This variable is deprecated. In MySQL 5.6, it is removed and the maximum parameter size is controlled by `max_allowed_packet'. * `max_prepared_stmt_count' Options for max_prepared_stmt_count *Version Introduced* 5.1.10 *Command-Line `--max_prepared_stmt_count=#'5.0.21 Format* *Option-File Format* `max_prepared_stmt_count'5.0.21 *Option Sets Yes, Variable* `max_prepared_stmt_count' *Variable Name* `max_prepared_stmt_count' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `numeric' *Default* `16382' *Range* `0-1048576' This variable limits the total number of prepared statements in the server. It can be used in environments where there is the potential for denial-of-service attacks based on running the server out of memory by preparing huge numbers of statements. If the value is set lower than the current number of prepared statements, existing statements are not affected and can be used, but no new statements can be prepared until the current number drops below the limit. The default value is 16,382. The permissible range of values is from 0 to 1 million. Setting the value to 0 disables prepared statements. This variable was added in MySQL 5.1.10. * `max_relay_log_size' Options for max_relay_log_size *Command-Line `--max_relay_log_size=#' Format* *Option-File Format* `max_relay_log_size' *Option Sets Yes, Variable* `max_relay_log_size' *Variable Name* `max_relay_log_size' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `numeric' *Default* `0' *Range* `0-1073741824' If a write by a replication slave to its relay log causes the current log file size to exceed the value of this variable, the slave rotates the relay logs (closes the current file and opens the next one). If `max_relay_log_size' is 0, the server uses `max_binlog_size' for both the binary log and the relay log. If `max_relay_log_size' is greater than 0, it constrains the size of the relay log, which enables you to have different sizes for the two logs. You must set `max_relay_log_size' to between 4096 bytes and 1GB (inclusive), or to 0. The default value is 0. See *Note replication-implementation-details::. * `max_seeks_for_key' Options for max_seeks_for_key *Command-Line `--max_seeks_for_key=#' Format* *Option-File Format* `max_seeks_for_key' *Option Sets Yes, Variable* `max_seeks_for_key' *Variable Name* `max_seeks_for_key' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Platform Bit Size* `32' *Type* `numeric' *Default* `4294967295' *Range* `1-4294967295' *Permitted Values * *Platform Bit Size* `64' *Type* `numeric' *Default* `18446744073709547520' *Range* `1-18446744073709547520' Limit the assumed maximum number of seeks when looking up rows based on a key. The MySQL optimizer assumes that no more than this number of key seeks are required when searching for matching rows in a table by scanning an index, regardless of the actual cardinality of the index (see *Note show-index::). By setting this to a low value (say, 100), you can force MySQL to prefer indexes instead of table scans. * `max_sort_length' Options for max_sort_length *Command-Line `--max_sort_length=#' Format* *Option-File Format* `max_sort_length' *Option Sets Yes, Variable* `max_sort_length' *Variable Name* `max_sort_length' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `numeric' *Default* `1024' *Range* `4-8388608' The number of bytes to use when sorting *Note `BLOB': blob. or *Note `TEXT': blob. values. Only the first `max_sort_length' bytes of each value are used; the rest are ignored. * `max_sp_recursion_depth' Options for max_sp_recursion_depth *Command-Line `--max_sp_recursion_depth[=#]' Format* *Option-File Format* `max_sp_recursion_depth' *Option Sets Yes, Variable* `max_sp_recursion_depth' *Variable Name* `max_sp_recursion_depth' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `numeric' *Default* `0' *Max Value* `255' The number of times that any given stored procedure may be called recursively. The default value for this option is 0, which completely disables recursion in stored procedures. The maximum value is 255. Stored procedure recursion increases the demand on thread stack space. If you increase the value of `max_sp_recursion_depth', it may be necessary to increase thread stack size by increasing the value of `thread_stack' at server startup. * `max_tmp_tables' Options for max_tmp_tables *Command-Line `--max_tmp_tables=#' Format* *Option-File Format* `max_tmp_tables' *Option Sets Yes, Variable* `max_tmp_tables' *Variable Name* `max_tmp_tables' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Platform Bit Size* `32' *Type* `numeric' *Default* `32' *Range* `1-4294967295' *Permitted Values * *Platform Bit Size* `64' *Type* `numeric' *Default* `32' *Range* `1-18446744073709547520' The maximum number of temporary tables a client can keep open at the same time. (This variable does not yet do anything.) * `max_user_connections' Options for max_user_connections *Command-Line `--max_user_connections=#' Format* *Option-File Format* `max_user_connections' *Option Sets Yes, Variable* `max_user_connections' *Variable Name* `max_user_connections' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `numeric' *Default* `0' *Range* `0-4294967295' The maximum number of simultaneous connections permitted to any given MySQL user account. A value of 0 (the default) means `no limit.' This variable has a global value that can be set at server startup or runtime. It also has a read-only session value that indicates the effective simultaneous-connection limit that applies to the account associated with the current session. The session value is initialized as follows: * If the user account has a nonzero `MAX_USER_CONNECTIONS' resource limit, the session `max_user_connections' value is set to that limit. * Otherwise, the session `max_user_connections' value is set to the global value. Account resource limits are specified using the *Note `GRANT': grant. statement. See *Note user-resources::, and *Note grant::. * `max_write_lock_count' Options for max_write_lock_count *Command-Line `--max_write_lock_count=#' Format* *Option-File Format* `max_write_lock_count' *Option Sets Yes, Variable* `max_write_lock_count' *Variable Name* `max_write_lock_count' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Platform Bit Size* `32' *Type* `numeric' *Default* `4294967295' *Range* `1-4294967295' *Permitted Values * *Platform Bit Size* `64' *Type* `numeric' *Default* `18446744073709547520' *Range* `1-18446744073709547520' After this many write locks, permit some pending read lock requests to be processed in between. * `min_examined_row_limit' Options for min-examined-row-limit *Version Introduced* 5.1.21 *Command-Line `--min-examined-row-limit=#' Format* *Option-File Format* `min-examined-row-limit' *Variable Name* `min_examined_row_limit' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Platform Bit Size* `32' *Type* `numeric' *Default* `0' *Range* `0-4294967295' *Permitted Values * *Platform Bit Size* `64' *Type* `numeric' *Default* `0' *Range* `0-18446744073709547520' Queries that examine fewer than this number of rows are not logged to the slow query log. This variable was added in MySQL 5.1.21. * `myisam_data_pointer_size' Options for myisam_data_pointer_size *Command-Line `--myisam_data_pointer_size=#' Format* *Option-File Format* `myisam_data_pointer_size' *Option Sets Yes, Variable* `myisam_data_pointer_size' *Variable Name* `myisam_data_pointer_size' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `numeric' *Default* `6' *Range* `2-7' The default pointer size in bytes, to be used by *Note `CREATE TABLE': create-table. for `MyISAM' tables when no `MAX_ROWS' option is specified. This variable cannot be less than 2 or larger than 7. The default value is 6. See *Note full-table::. * `myisam_max_sort_file_size' Options for myisam_max_sort_file_size *Command-Line `--myisam_max_sort_file_size=#' Format* *Option-File Format* `myisam_max_sort_file_size' *Option Sets Yes, Variable* `myisam_max_sort_file_size' *Variable Name* `myisam_max_sort_file_size' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `numeric' *Default* `2147483648' The maximum size of the temporary file that MySQL is permitted to use while re-creating a `MyISAM' index (during *Note `REPAIR TABLE': repair-table, *Note `ALTER TABLE': alter-table, or *Note `LOAD DATA INFILE': load-data.). If the file size would be larger than this value, the index is created using the key cache instead, which is slower. The value is given in bytes. The default value is 2GB. If `MyISAM' index files exceed this size and disk space is available, increasing the value may help performance. The space must be available in the file system containing the directory where the original index file is located. * `myisam_mmap_size' Options for myisam_mmap_size *Version Introduced* 5.1.43 *Command-Line `--myisam_mmap_size=#' Format* *Option-File Format* `myisam_mmap_size' *Option Sets Yes, Variable* `myisam_mmap_size' *Variable Name* `myisam_mmap_size' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Platform Bit Size* `32' *Type* `numeric' *Default* `4294967295' *Range* `7-4294967295' *Permitted Values * *Platform Bit Size* `64' *Type* `numeric' *Default* `18446744073709547520' *Range* `7-18446744073709547520' The maximum amount of memory to use for memory mapping compressed *Note `MyISAM': myisam-storage-engine. files. If many compressed `MyISAM' tables are used, the value can be decreased to reduce the likelihood of memory-swapping problems. This variable was added in MySQL 5.1.43. * `myisam_recover_options' Options for myisam_recover_options *Variable Name* `myisam_recover_options' *Variable Scope* Global *Dynamic Variable* No The value of the `--myisam-recover' option. See *Note server-options::. * `myisam_repair_threads' Options for myisam_repair_threads *Command-Line `--myisam_repair_threads=#' Format* *Option-File Format* `myisam_repair_threads' *Option Sets Yes, Variable* `myisam_repair_threads' *Variable Name* `myisam_repair_threads' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Platform Bit Size* `32' *Type* `numeric' *Default* `1' *Range* `1-4294967295' *Permitted Values * *Platform Bit Size* `64' *Type* `numeric' *Default* `1' *Range* `1-18446744073709547520' If this value is greater than 1, `MyISAM' table indexes are created in parallel (each index in its own thread) during the `Repair by sorting' process. The default value is 1. *Note*: Multi-threaded repair is still _beta-quality_ code. * `myisam_sort_buffer_size' Options for myisam_sort_buffer_size *Command-Line `--myisam_sort_buffer_size=#' Format* *Option-File Format* `myisam_sort_buffer_size' *Option Sets Yes, Variable* `myisam_sort_buffer_size' *Variable Name* `myisam_sort_buffer_size' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Platform Bit Size* `32' *Type* `numeric' *Default* `8388608' *Range* `4-4294967295' *Permitted Values * *Platform Bit Size* `64' *Type* `numeric' *Default* `8388608' *Range* `4-18446744073709547520' The size of the buffer that is allocated when sorting `MyISAM' indexes during a *Note `REPAIR TABLE': repair-table. or when creating indexes with *Note `CREATE INDEX': create-index. or *Note `ALTER TABLE': alter-table. The maximum permissible setting for `myisam_sort_buffer_size' is 4GB. As of MySQL 5.1.23, values larger than 4GB are permitted for 64-bit platforms (except 64-bit Windows, for which large values are truncated to 4GB with a warning). * `myisam_stats_method' Options for myisam_stats_method *Command-Line `--myisam_stats_method=name' Format* *Option-File Format* `myisam_stats_method' *Option Sets Yes, Variable* `myisam_stats_method' *Variable Name* `myisam_stats_method' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `enumeration' *Valid Values* `nulls_equal' `nulls_unequal' `nulls_ignored' How the server treats `NULL' values when collecting statistics about the distribution of index values for `MyISAM' tables. This variable has three possible values, `nulls_equal', `nulls_unequal', and `nulls_ignored'. For `nulls_equal', all `NULL' index values are considered equal and form a single value group that has a size equal to the number of `NULL' values. For `nulls_unequal', `NULL' values are considered unequal, and each `NULL' forms a distinct value group of size 1. For `nulls_ignored', `NULL' values are ignored. The method that is used for generating table statistics influences how the optimizer chooses indexes for query execution, as described in *Note myisam-index-statistics::. Any unique prefix of a valid value may be used to set the value of this variable. * `myisam_use_mmap' Options for myisam_use_mmap *Version Introduced* 5.1.4 *Command-Line `--myisam_use_mmap' Format* *Option-File Format* `myisam_use_mmap' *Option Sets Yes, Variable* `myisam_use_mmap' *Variable Name* `myisam_use_mmap' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `boolean' *Default* `OFF' Use memory mapping for reading and writing `MyISAM' tables. This variable was added in MySQL 5.1.4. * `named_pipe' Options for named_pipe *Variable Name* `named_pipe' *Variable Scope* Global *Dynamic Variable* No *Platform Specific* windows *Permitted Values * *Type* (windows) `boolean' *Default* `OFF' (Windows only.) Indicates whether the server supports connections over named pipes. * `net_buffer_length' Options for net_buffer_length *Command-Line `--net_buffer_length=#' Format* *Option-File Format* `net_buffer_length' *Option Sets Yes, Variable* `net_buffer_length' *Variable Name* `net_buffer_length' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `numeric' *Default* `16384' *Range* `1024-1048576' Each client thread is associated with a connection buffer and result buffer. Both begin with a size given by `net_buffer_length' but are dynamically enlarged up to `max_allowed_packet' bytes as needed. The result buffer shrinks to `net_buffer_length' after each SQL statement. This variable should not normally be changed, but if you have very little memory, you can set it to the expected length of statements sent by clients. If statements exceed this length, the connection buffer is automatically enlarged. The maximum value to which `net_buffer_length' can be set is 1MB. As of MySQL 5.1.31, the session value of this variable is read only. Before 5.1.31, setting the session value is permitted but has no effect. * `net_read_timeout' Options for net_read_timeout *Command-Line `--net_read_timeout=#' Format* *Option-File Format* `net_read_timeout' *Option Sets Yes, Variable* `net_read_timeout' *Variable Name* `net_read_timeout' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `numeric' *Default* `30' *Min Value* `1' The number of seconds to wait for more data from a connection before aborting the read. Before MySQL 5.1.41, this timeout applies only to TCP/IP connections, not to connections made through Unix socket files, named pipes, or shared memory. When the server is reading from the client, `net_read_timeout' is the timeout value controlling when to abort. When the server is writing to the client, `net_write_timeout' is the timeout value controlling when to abort. See also `slave_net_timeout'. On Linux, the `NO_ALARM' build flag affects timeout behavior as indicated in the description of the `net_retry_count' system variable. * `net_retry_count' Options for net_retry_count *Command-Line `--net_retry_count=#' Format* *Option-File Format* `net_retry_count' *Option Sets Yes, Variable* `net_retry_count' *Variable Name* `net_retry_count' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Platform Bit Size* `32' *Type* `numeric' *Default* `10' *Range* `1-4294967295' *Permitted Values * *Platform Bit Size* `64' *Type* `numeric' *Default* `10' *Range* `1-18446744073709547520' If a read or write on a communication port is interrupted, retry this many times before giving up. This value should be set quite high on FreeBSD because internal interrupts are sent to all threads. On Linux, the `NO_ALARM' build flag (`-DNO_ALARM') modifies how the binary treats both `net_read_timeout' and `net_write_timeout'. With this flag enabled, neither timer cancels the current statement until after the failing connection has been waited on an additional `net_retry_count' times. This means that the effective timeout value becomes `(timeout setting) x (net_retry_count+1)'. * `net_write_timeout' Options for net_write_timeout *Command-Line `--net_write_timeout=#' Format* *Option-File Format* `net_write_timeout' *Option Sets Yes, Variable* `net_write_timeout' *Variable Name* `net_write_timeout' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `numeric' *Default* `60' *Min Value* `1' The number of seconds to wait for a block to be written to a connection before aborting the write. Before MySQL 5.1.41, this timeout applies only to TCP/IP connections, not to connections made using Unix socket files, named pipes, or shared memory. See also `net_read_timeout'. On Linux, the `NO_ALARM' build flag affects timeout behavior as indicated in the description of the `net_retry_count' system variable. * `new' Options for new *Command-Line `--new' Format* ** `-n' *Option-File Format* `new' *Option Sets Yes, Variable* `new' *Variable Name* `new' *Variable Scope* Global, Session *Dynamic Variable* Yes *Disabled by* `skip-new' *Permitted Values * *Type* `boolean' *Default* `FALSE' This variable was used in MySQL 4.0 to turn on some 4.1 behaviors, and is retained for backward compatibility. In MySQL 5.1, its value is always `OFF'. * `old' Options for old *Version Introduced* 5.1.18 *Command-Line `--old' Format* *Option-File Format* `old' *Variable Name* `old' *Variable Scope* Global *Dynamic Variable* No `old' is a compatibility variable. It is disabled by default, but can be enabled at startup to revert the server to behaviors present in older versions. Currently, when `old' is enabled, it changes the default scope of index hints to that used prior to MySQL 5.1.17. That is, index hints with no `FOR' clause apply only to how indexes are used for row retrieval and not to resolution of `ORDER BY' or `GROUP BY' clauses. (See *Note index-hints::.) Take care about enabling this in a replication setup. With statement-based binary logging, having different modes for the master and slaves might lead to replication errors. This variable was added as `old_mode' in MySQL 5.1.17 and renamed to `old' in MySQL 5.1.18. * `old_alter_table' Options for old-alter-table *Command-Line `--old-alter-table' Format* *Option-File Format* `old-alter-table' *Option Sets Yes, Variable* `old_alter_table' *Variable Name* `old_alter_table' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `boolean' *Default* `OFF' When this variable is enabled, the server does not use the optimized method of processing an *Note `ALTER TABLE': alter-table. operation. It reverts to using a temporary table, copying over the data, and then renaming the temporary table to the original, as used by MySQL 5.0 and earlier. For more information on the operation of *Note `ALTER TABLE': alter-table, see *Note alter-table::. * `old_passwords' Options for old-passwords *Command-Line `--old_passwords' Format* *Option-File Format* `old-passwords' *Option Sets Yes, Variable* `old_passwords' *Variable Name* `old_passwords' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `boolean' *Default* `FALSE' Whether the server should use pre-4.1-style passwords for MySQL user accounts. See *Note old-client::. * `one_shot' This is not a variable, but it can be used when setting some variables. It is described in *Note set-option::. * `open_files_limit' Options for open-files-limit *Command-Line `--open-files-limit=#' Format* *Option-File Format* `open-files-limit' *Option Sets Yes, Variable* `open_files_limit' *Variable Name* `open_files_limit' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `numeric' *Default* `0' *Range* `0-65535' The number of files that the operating system permits *Note `mysqld': mysqld. to open. This is the real value permitted by the system and might be different from the value you gave using the `--open-files-limit' option to *Note `mysqld': mysqld. or *Note `mysqld_safe': mysqld-safe. The value is 0 on systems where MySQL cannot change the number of open files. * `optimizer_prune_level' Options for optimizer_prune_level *Command-Line `--optimizer_prune_level[=#]' Format* *Option-File Format* `optimizer_prune_level' *Option Sets Yes, Variable* `optimizer_prune_level' *Variable Name* `optimizer_prune_level' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `boolean' *Default* `1' Controls the heuristics applied during query optimization to prune less-promising partial plans from the optimizer search space. A value of 0 disables heuristics so that the optimizer performs an exhaustive search. A value of 1 causes the optimizer to prune plans based on the number of rows retrieved by intermediate plans. * `optimizer_search_depth' Options for optimizer_search_depth *Command-Line `--optimizer_search_depth[=#]' Format* *Option-File Format* `optimizer_search_depth' *Option Sets Yes, Variable* `optimizer_search_depth' *Variable Name* `optimizer_search_depth' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `numeric' *Default* `62' The maximum depth of search performed by the query optimizer. Values larger than the number of relations in a query result in better query plans, but take longer to generate an execution plan for a query. Values smaller than the number of relations in a query return an execution plan quicker, but the resulting plan may be far from being optimal. If set to 0, the system automatically picks a reasonable value. If set to 63, the optimizer switches to the algorithm used in MySQL 5.0.0 (and previous versions) for performing searches. The value of 63 is deprecated and will be treated as invalid in a future MySQL release. * `optimizer_switch' Options for optimizer_switch *Version Introduced* 5.1.34 *Command-Line `--optimizer_switch=value' Format* *Option-File Format* `optimizer_switch' ** `optimizer_switch'5.4.2 ** `optimizer_switch'6.0.11 *Option Sets Yes, Variable* `optimizer_switch' *Variable Name* `optimizer_switch' *Variable Scope* Global, Session *Dynamic Variable* Yes The `optimizer_switch' system variable enables control over optimizer behaviors. The value of this variable is a set of flags, each of which has a value of `on' or `off' to indicate whether the corresponding optimizer behavior is enabled or disabled. This variable has global and session values and can be changed at runtime. The global default can be set at server startup. To see the current set of optimizer flags, select the variable value: mysql> SELECT @@optimizer_switch\G *************************** 1. row *************************** @@optimizer_switch: index_merge=on,index_merge_union=on, index_merge_sort_union=on,index_merge_intersection=on For more information about the syntax of this variable and the optimizer behaviors that it controls, see *Note switchable-optimizations::. * `pid_file' Options for pid-file *Command-Line `--pid-file=file_name' Format* *Option-File Format* `pid-file=file_name' *Option Sets Yes, Variable* `pid_file' *Variable Name* `pid_file' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `file name' The path name of the process ID (PID) file. This variable can be set with the `--pid-file' option. * `plugin_dir' Options for plugin_dir *Version Introduced* 5.1.2 *Command-Line `--plugin_dir=path' Format* *Option-File Format* `plugin_dir' *Option Sets Yes, Variable* `plugin_dir' *Variable Name* `plugin_dir' *Variable Scope* Global *Dynamic Variable* No *Permitted Values (>= 5.1.2)* *Type* (other) `directory name' *Default* `BASEDIR/lib/mysql/plugin' *Permitted Values (>= 5.1.2)* *Type* (windows) `directory name' *Default* `BASEDIR/lib/plugin' The path name of the plugin directory. This variable was added in MySQL 5.1.2. If the plugin directory is writable by the server, it may be possible for a user to write executable code to a file in the directory using *Note `SELECT ... INTO DUMPFILE': select. This can be prevented by making `plugin_dir' read only to the server or by setting `--secure-file-priv' to a directory where *Note `SELECT': select. writes can be made safely. * `port' Options for port *Command-Line `--port=#' Format* ** `-P' *Option-File Format* `port' *Option Sets Yes, Variable* `port' *Variable Name* `port' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `numeric' *Default* `3306' The number of the port on which the server listens for TCP/IP connections. This variable can be set with the `--port' option. * `preload_buffer_size' Options for preload_buffer_size *Command-Line `--preload_buffer_size=#' Format* *Option-File Format* `preload_buffer_size' *Option Sets Yes, Variable* `preload_buffer_size' *Variable Name* `preload_buffer_size' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `numeric' *Default* `32768' *Range* `1024-1073741824' The size of the buffer that is allocated when preloading indexes. * `prepared_stmt_count' The current number of prepared statements. (The maximum number of statements is given by the `max_prepared_stmt_count' system variable.) This variable was added in MySQL 5.1.10. In MySQL 5.1.14, it was converted to the global `Prepared_stmt_count' status variable. * `profiling' If set to 0 (the default), statement profiling is disabled. If set to 1, statement profiling is enabled and the *Note `SHOW PROFILES': show-profiles. and *Note `SHOW PROFILE': show-profile. statements provide access to profiling information. See *Note show-profiles::. This variable was added in MySQL 5.1.24. * `profiling_history_size' The number of statements for which to maintain profiling information if `profiling' is enabled. The default value is 15. The maximum value is 100. Setting the value to 0 effectively disables profiling. See *Note show-profiles::. This variable was added in MySQL 5.1.24. * `protocol_version' Options for protocol_version *Variable Name* `protocol_version' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `numeric' The version of the client/server protocol used by the MySQL server. * `pseudo_thread_id' Options for pseudo_thread_id *Variable Name* `pseudo_thread_id' *Variable Scope* Session *Dynamic Variable* Yes *Permitted Values * *Type* `numeric' This variable is for internal server use. * `query_alloc_block_size' Options for query_alloc_block_size *Command-Line `--query_alloc_block_size=#' Format* *Option-File Format* `query_alloc_block_size' *Option Sets Yes, Variable* `query_alloc_block_size' *Variable Name* `query_alloc_block_size' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Platform Bit Size* `32' *Type* `numeric' *Default* `8192' *Range* `1024-4294967295' *Block Size* `1024' *Permitted Values * *Platform Bit Size* `64' *Type* `numeric' *Default* `8192' *Range* `1024-18446744073709547520' *Block Size* `1024' The allocation size of memory blocks that are allocated for objects created during statement parsing and execution. If you have problems with memory fragmentation, it might help to increase this parameter. * `query_cache_limit' Options for query_cache_limit *Command-Line `--query_cache_limit=#' Format* *Option-File Format* `query_cache_limit' *Option Sets Yes, Variable* `query_cache_limit' *Variable Name* `query_cache_limit' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Platform Bit Size* `32' *Type* `numeric' *Default* `1048576' *Range* `0-4294967295' *Permitted Values * *Platform Bit Size* `64' *Type* `numeric' *Default* `1048576' *Range* `0-18446744073709547520' Do not cache results that are larger than this number of bytes. The default value is 1MB. * `query_cache_min_res_unit' Options for query_cache_min_res_unit *Command-Line `--query_cache_min_res_unit=#' Format* *Option-File Format* `query_cache_min_res_unit' *Option Sets Yes, Variable* `query_cache_min_res_unit' *Variable Name* `query_cache_min_res_unit' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Platform Bit Size* `32' *Type* `numeric' *Default* `4096' *Range* `512-4294967295' *Permitted Values * *Platform Bit Size* `64' *Type* `numeric' *Default* `4096' *Range* `512-18446744073709547520' The minimum size (in bytes) for blocks allocated by the query cache. The default value is 4096 (4KB). Tuning information for this variable is given in *Note query-cache-configuration::. * `query_cache_size' Options for query_cache_size *Command-Line `--query_cache_size=#' Format* *Option-File Format* `query_cache_size' *Option Sets Yes, Variable* `query_cache_size' *Variable Name* `query_cache_size' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Platform Bit Size* `32' *Type* `numeric' *Default* `0' *Range* `0-4294967295' *Permitted Values * *Platform Bit Size* `64' *Type* `numeric' *Default* `0' *Range* `0-18446744073709547520' The amount of memory allocated for caching query results. The default value is 0, which disables the query cache. The permissible values are multiples of 1024; other values are rounded down to the nearest multiple. Note that `query_cache_size' bytes of memory are allocated even if `query_cache_type' is set to 0. See *Note query-cache-configuration::, for more information. The query cache needs a minimum size of about 40KB to allocate its structures. (The exact size depends on system architecture.) If you set the value of `query_cache_size' too small, a warning will occur, as described in *Note query-cache-configuration::. * `query_cache_type' Options for query_cache_type *Command-Line `--query_cache_type=#' Format* *Option-File Format* `query_cache_type' *Option Sets Yes, Variable* `query_cache_type' *Variable Name* `query_cache_type' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `enumeration' *Default* `1' *Valid Values* `0' `1' `2' Set the query cache type. Setting the `GLOBAL' value sets the type for all clients that connect thereafter. Individual clients can set the `SESSION' value to affect their own use of the query cache. Possible values are shown in the following table. Option Description `0' or Do not cache results in or retrieve results `OFF' from the query cache. Note that this does not deallocate the query cache buffer. To do that, you should set `query_cache_size' to 0. `1' or Cache all cacheable query results except for `ON' those that begin with `SELECT SQL_NO_CACHE'. `2' or Cache results only for cacheable queries that `DEMAND' begin with `SELECT SQL_CACHE'. This variable defaults to `ON'. Any unique prefix of a valid value may be used to set the value of this variable. * `query_cache_wlock_invalidate' Options for query_cache_wlock_invalidate *Command-Line `--query_cache_wlock_invalidate' Format* *Option-File Format* `query_cache_wlock_invalidate' *Option Sets Yes, Variable* `query_cache_wlock_invalidate' *Variable Name* `query_cache_wlock_invalidate' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `boolean' *Default* `FALSE' Normally, when one client acquires a `WRITE' lock on a `MyISAM' table, other clients are not blocked from issuing statements that read from the table if the query results are present in the query cache. Setting this variable to 1 causes acquisition of a `WRITE' lock for a table to invalidate any queries in the query cache that refer to the table. This forces other clients that attempt to access the table to wait while the lock is in effect. * `query_prealloc_size' Options for query_prealloc_size *Command-Line `--query_prealloc_size=#' Format* *Option-File Format* `query_prealloc_size' *Option Sets Yes, Variable* `query_prealloc_size' *Variable Name* `query_prealloc_size' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Platform Bit Size* `32' *Type* `numeric' *Default* `8192' *Range* `8192-4294967295' *Block Size* `1024' *Permitted Values * *Platform Bit Size* `64' *Type* `numeric' *Default* `8192' *Range* `8192-18446744073709547520' *Block Size* `1024' The size of the persistent buffer used for statement parsing and execution. This buffer is not freed between statements. If you are running complex queries, a larger `query_prealloc_size' value might be helpful in improving performance, because it can reduce the need for the server to perform memory allocation during query execution operations. * `rand_seed1' The `rand_seed1' and `rand_seed2' variables exist as session variables only, and can be set but not read. Beginning with MySQL 5.1.18, the variables--but not their values--are shown in the output of *Note `SHOW VARIABLES': show-variables. The purpose of these variables is to support replication of the `RAND()' function. For statements that invoke `RAND()', the master passes two values to the slave, where they are used to seed the random number generator. The slave uses these values to set the session variables `rand_seed1' and `rand_seed2' so that `RAND()' on the slave generates the same value as on the master. * `rand_seed2' See the description for `rand_seed1'. * `range_alloc_block_size' Options for range_alloc_block_size *Command-Line `--range_alloc_block_size=#' Format* *Option-File Format* `range_alloc_block_size' *Option Sets Yes, Variable* `range_alloc_block_size' *Variable Name* `range_alloc_block_size' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Platform Bit Size* `32' *Type* `numeric' *Default* `4096' *Range* `4096-4294967295' *Block Size* `1024' The size of blocks that are allocated when doing range optimization. * `read_buffer_size' Options for read_buffer_size *Command-Line `--read_buffer_size=#' Format* *Option-File Format* `read_buffer_size' *Option Sets Yes, Variable* `read_buffer_size' *Variable Name* `read_buffer_size' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `numeric' *Default* `131072' *Range* `8200-2147479552' Each thread that does a sequential scan allocates a buffer of this size (in bytes) for each table it scans. If you do many sequential scans, you might want to increase this value, which defaults to 131072. The value of this variable should be a multiple of 4KB. If it is set to a value that is not a multiple of 4KB, its value will be rounded down to the nearest multiple of 4KB. The maximum permissible setting for `read_buffer_size' is 2GB. `read_buffer_size' and `read_rnd_buffer_size' are not specific to any storage engine and apply in a general manner for optimization. See *Note memory-use::, for example. * `read_only' Options for read_only *Command-Line `--read-only' Format* *Option-File Format* `read_only' *Option Sets Yes, Variable* `read_only' *Variable Name* `read_only' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `numeric' *Default* `0' This variable is off by default. When it is enabled, the server permits no updates except from users that have the `SUPER' privilege or (on a slave server) from updates performed by slave threads. In replication setups, it can be useful to enable `read_only' on slave servers to ensure that slaves accept updates only from the master server and not from clients. `read_only' does not apply to `TEMPORARY' tables, nor does it prevent the server from inserting rows into the log tables (see *Note log-destinations::). This variable does not prevent the use of *Note `ANALYZE TABLE': analyze-table. or *Note `OPTIMIZE TABLE': optimize-table. statements because its purpose is to prevent changes to table structure or contents. Analysis and optimization do not qualify as such changes. This means, for example, that consistency checks on read-only slaves can be performed with *Note `mysqlcheck --all-databases --analyze': mysqlcheck. `read_only' exists only as a `GLOBAL' variable, so changes to its value require the `SUPER' privilege. Changes to `read_only' on a master server are not replicated to slave servers. The value can be set on a slave server independent of the setting on the master. *Important*: In MySQL 5.1, enabling `read_only' prevents the use of the *Note `SET PASSWORD': set-password. statement by any user not having the `SUPER' privilege. This is not necessarily the case for all MySQL release series. When replicating from one MySQL release series to another (for example, from a MySQL 5.0 master to a MySQL 5.1 or later slave), you should check the documentation for the versions running on both master and slave to determine whether the behavior of `read_only' in this regard is or is not the same, and, if it is different, whether this has an impact on your applications. As of MySQL 5.1.15, the following conditions apply: * If you attempt to enable `read_only' while you have any explicit locks (acquired with *Note `LOCK TABLES': lock-tables.) or have a pending transaction, an error occurs. * If you attempt to enable `read_only' while other clients hold explicit table locks or have pending transactions, the attempt blocks until the locks are released and the transactions end. While the attempt to enable `read_only' is pending, requests by other clients for table locks or to begin transactions also block until `read_only' has been set. * `read_only' can be enabled while you hold a global read lock (acquired with *Note `FLUSH TABLES WITH READ LOCK': flush.) because that does not involve table locks. * `read_rnd_buffer_size' Options for read_rnd_buffer_size *Command-Line `--read_rnd_buffer_size=#' Format* *Option-File Format* `read_rnd_buffer_size' *Option Sets Yes, Variable* `read_rnd_buffer_size' *Variable Name* `read_rnd_buffer_size' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `numeric' *Default* `262144' *Range* `8200-4294967295' When reading rows in sorted order following a key-sorting operation, the rows are read through this buffer to avoid disk seeks. See *Note order-by-optimization::. Setting the variable to a large value can improve `ORDER BY' performance by a lot. However, this is a buffer allocated for each client, so you should not set the global variable to a large value. Instead, change the session variable only from within those clients that need to run large queries. The maximum permissible setting for `read_rnd_buffer_size' is 2GB. `read_buffer_size' and `read_rnd_buffer_size' are not specific to any storage engine and apply in a general manner for optimization. See *Note memory-use::, for example. * `relay_log_purge' Options for relay_log_purge *Command-Line `--relay_log_purge' Format* *Option-File Format* `relay_log_purge' *Option Sets Yes, Variable* `relay_log_purge' *Variable Name* `relay_log_purge' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `boolean' *Default* `TRUE' Disables or enables automatic purging of relay log files as soon as they are not needed any more. The default value is 1 (`ON'). * `relay_log_space_limit' Options for relay_log_space_limit *Command-Line `--relay_log_space_limit=#' Format* *Option-File Format* `relay_log_space_limit' *Option Sets Yes, Variable* `relay_log_space_limit' *Variable Name* `relay_log_space_limit' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Platform Bit Size* `32' *Type* `numeric' *Default* `0' *Range* `0-4294967295' *Permitted Values * *Platform Bit Size* `64' *Type* `numeric' *Default* `0' *Range* `0-18446744073709547520' The maximum amount of space to use for all relay logs. * `report_host' Options for report-host *Command-Line `--report-host=host_name' Format* *Option-File Format* `report-host' *Option Sets Yes, Variable* `report_host' *Variable Name* `report-host' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `string' The value of the `--report-host' option. This variable was added in MySQL 5.1.24. * `report_password' Options for report-password *Command-Line `--report-password=name' Format* *Option-File Format* `report-password' *Option Sets Yes, Variable* `report_password' *Variable Name* `report-password' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `string' The value of the `--report-password' option. Not the same as the password for the MySQL replication user account. This variable was added in MySQL 5.1.24. * `report_port' Options for report-port *Command-Line `--report-port=#' Format* *Option-File Format* `report-port' *Option Sets Yes, Variable* `report_port' *Variable Name* `report-port' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `numeric' *Default* `3306' The value of the `--report-port' option. This variable was added in MySQL 5.1.24. * `report_user' Options for report-user *Command-Line `--report-user=name' Format* *Option-File Format* `report-user' *Option Sets Yes, Variable* `report_user' *Variable Name* `report-user' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `string' The value of the `--report-user' option. This variable was added in MySQL 5.1.24. * `secure_auth' Options for secure-auth *Command-Line `--secure-auth' Format* *Option-File Format* `secure-auth' *Option Sets Yes, Variable* `secure_auth' *Variable Name* `secure_auth' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `boolean' *Default* `FALSE' If the MySQL server has been started with the `--secure-auth' option, it blocks connections from all accounts that have passwords stored in the old (pre-4.1) format. In that case, the value of this variable is `ON', otherwise it is `OFF'. You should enable this option if you want to prevent all use of passwords employing the old format (and hence insecure communication over the network). Server startup fails with an error if this option is enabled and the privilege tables are in pre-4.1 format. See *Note old-client::. * `secure_file_priv' Options for secure-file-priv *Version Introduced* 5.1.17 *Command-Line `--secure-file-priv=path' Format* *Option-File Format* `secure-file-priv=path' *Option Sets Yes, Variable* `secure_file_priv' *Variable Name* `secure-file-priv' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `string' By default, this variable is empty. If set to the name of a directory, it limits the effect of the `LOAD_FILE()' function and the *Note `LOAD DATA': load-data. and *Note `SELECT ... INTO OUTFILE': select. statements to work only with files in that directory. This variable was added in MySQL 5.1.17. * `server_id' Options for server-id *Command-Line `--server-id=#' Format* *Option-File Format* `server-id' *Option Sets Yes, Variable* `server_id' *Variable Name* `server_id' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `numeric' *Default* `0' *Range* `0-4294967295' The server ID, used in replication to give each master and slave a unique identity. This variable is set by the `--server-id' option. For each server participating in replication, you should pick a positive integer in the range from 1 to 2^32 - 1 to act as that server's ID. * `shared_memory' Options for shared_memory *Variable Name* `shared_memory' *Variable Scope* Global *Dynamic Variable* No *Platform Specific* windows (Windows only.) Whether the server permits shared-memory connections. * `shared_memory_base_name' Options for shared_memory_base_name *Variable Name* `shared_memory_base_name' *Variable Scope* Global *Dynamic Variable* No *Platform Specific* windows (Windows only.) The name of shared memory to use for shared-memory connections. This is useful when running multiple MySQL instances on a single physical machine. The default name is `MYSQL'. The name is case sensitive. * `skip_external_locking' This is `OFF' if *Note `mysqld': mysqld. uses external locking, `ON' if external locking is disabled. This affects only *Note `MyISAM': myisam-storage-engine. table access. * `skip_name_resolve' This variable is set from the value of the `--skip-name-resolve' option. If it is `ON', *Note `mysqld': mysqld. resolves host names when checking client connections. If `OFF', *Note `mysqld': mysqld. uses only IP numbers and all `Host' column values in the grant tables must be IP addresses or `localhost'. See *Note dns::. This variable was added in MySQL 5.1.46. * `skip_networking' This is `ON' if the server permits only local (non-TCP/IP) connections. On Unix, local connections use a Unix socket file. On Windows, local connections use a named pipe or shared memory. On NetWare, only TCP/IP connections are supported, so do not set this variable to `ON'. This variable can be set to `ON' with the `--skip-networking' option. * `skip_show_database' This prevents people from using the *Note `SHOW DATABASES': show-databases. statement if they do not have the `SHOW DATABASES' privilege. This can improve security if you have concerns about users being able to see databases belonging to other users. Its effect depends on the `SHOW DATABASES' privilege: If the variable value is `ON', the *Note `SHOW DATABASES': show-databases. statement is permitted only to users who have the `SHOW DATABASES' privilege, and the statement displays all database names. If the value is `OFF', *Note `SHOW DATABASES': show-databases. is permitted to all users, but displays the names of only those databases for which the user has the `SHOW DATABASES' or other privilege. * `slow_launch_time' Options for slow_launch_time *Command-Line `--slow_launch_time=#' Format* *Option-File Format* `slow_launch_time' *Option Sets Yes, Variable* `slow_launch_time' *Variable Name* `slow_launch_time' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `numeric' *Default* `2' If creating a thread takes longer than this many seconds, the server increments the `Slow_launch_threads' status variable. * `slow_query_log' Whether the slow query log is enabled. The value can be 0 (or `OFF') to disable the log or 1 (or `ON') to enable the log. The default value depends on whether the `--slow_query_log' option is given (`--log-slow-queries' before MySQL 5.1.29). The destination for log output is controlled by the `log_output' system variable; if that value is `NONE', no log entries are written even if the log is enabled. The `slow_query_log' variable was added in MySQL 5.1.12. * `slow_query_log_file' Options for slow_query_log_file *Version Introduced* 5.1.12 *Command-Line `--slow-query-log-file=file_name' Format* *Option-File Format* `slow_query_log_file' *Option Sets Yes, Variable* `slow_query_log_file' *Variable Name* `slow_query_log_file' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `file name' The name of the slow query log file. The default value is `HOST_NAME-slow.log', but the initial value can be changed with the `--slow_query_log_file' option (`--log-slow-queries' before MySQL 5.1.29). This variable was added in MySQL 5.1.12. * `socket' Options for socket *Command-Line `--socket=name' Format* *Option-File Format* `socket' *Option Sets Yes, Variable* `socket' *Variable Name* `socket' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `file name' *Default* `/tmp/mysql.sock' On Unix platforms, this variable is the name of the socket file that is used for local client connections. The default is `/tmp/mysql.sock'. (For some distribution formats, the directory might be different, such as `/var/lib/mysql' for RPMs.) On Windows, this variable is the name of the named pipe that is used for local client connections. The default value is `MySQL' (not case sensitive). * `sort_buffer_size' Options for sort_buffer_size *Command-Line `--sort_buffer_size=#' Format* *Option-File Format* `sort_buffer_size' *Option Sets Yes, Variable* `sort_buffer_size' *Variable Name* `sort_buffer_size' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Platform Bit Size* `32' *Type* `numeric' *Default* `2097144' *Max Value* `4294967295' *Permitted Values * *Platform Bit Size* `64' *Type* `numeric' *Default* `2097144' *Max Value* `18446744073709547520' Each session that needs to do a sort allocates a buffer of this size. `sort_buffer_size' is not specific to any storage engine and applies in a general manner for optimization. See *Note order-by-optimization::, for example. If you see many `Sort_merge_passes' per second in *Note `SHOW GLOBAL STATUS': show-status. output, you can consider increasing the `sort_buffer_size' value to speed up `ORDER BY' or `GROUP BY' operations that cannot be improved with query optimization or improved indexing. The entire buffer is allocated even if it is not all needed, so setting it larger than required globally will slow down most queries that sort. It is best to increase it as a session setting, and only for the sessions that need a larger size. On Linux, there are thresholds of 256KB and 2MB where larger values may significantly slow down memory allocation, so you should consider staying below one of those values. Experiment to find the best value for your workload. See *Note temporary-files::. The maximum permissible setting for `sort_buffer_size' is 4GB. As of MySQL 5.1.23, values larger than 4GB are permitted for 64-bit platforms (except 64-bit Windows, for which large values are truncated to 4GB with a warning). * `sql_auto_is_null' Options for sql_auto_is_null *Variable Name* `sql_auto_is_null' *Variable Scope* Session *Dynamic Variable* Yes If this variable is set to 1 (the default), then after a statement that successfully inserts an automatically generated `AUTO_INCREMENT' value, you can find that value by issuing a statement of the following form: SELECT * FROM TBL_NAME WHERE AUTO_COL IS NULL If the statement returns a row, the value returned is the same as if you invoked the `LAST_INSERT_ID()' function. For details, including the return value after a multiple-row insert, see *Note information-functions::. If no `AUTO_INCREMENT' value was successfully inserted, the *Note `SELECT': select. statement returns no row. The behavior of retrieving an `AUTO_INCREMENT' value by using an `IS NULL' comparison is used by some ODBC programs, such as Access. See *Note connector-odbc-usagenotes-functionality-last-insert-id::. This behavior can be disabled by setting `sql_auto_is_null' to 0. * `sql_big_selects' Options for sql_big_selects *Variable Name* `sql_big_selects' *Variable Scope* Session *Dynamic Variable* Yes *Permitted Values * *Type* `boolean' *Default* `1' If set to 0, MySQL aborts *Note `SELECT': select. statements that are likely to take a very long time to execute (that is, statements for which the optimizer estimates that the number of examined rows exceeds the value of `max_join_size'). This is useful when an inadvisable `WHERE' statement has been issued. The default value for a new connection is 1, which permits all *Note `SELECT': select. statements. If you set the `max_join_size' system variable to a value other than `DEFAULT', `sql_big_selects' is set to 0. * `sql_buffer_result' Options for sql_buffer_result *Variable Name* `sql_buffer_result' *Variable Scope* Session *Dynamic Variable* Yes *Permitted Values * *Type* `boolean' *Default* `0' If set to 1, `sql_buffer_result' forces results from *Note `SELECT': select. statements to be put into temporary tables. This helps MySQL free the table locks early and can be beneficial in cases where it takes a long time to send results to the client. The default value is 0. * `sql_log_bin' Options for sql_log_bin *Variable Name* `sql_log_bin' *Variable Scope* Session *Dynamic Variable* Yes *Permitted Values * *Type* `boolean' If set to 0, no logging is done to the binary log for the client. The client must have the `SUPER' privilege to set this option. The default value is 1. * `sql_log_off' Options for sql_log_off *Variable Name* `sql_log_off' *Variable Scope* Session *Dynamic Variable* Yes *Permitted Values * *Type* `boolean' *Default* `0' If set to 1, no logging is done to the general query log for this client. The client must have the `SUPER' privilege to set this option. The default value is 0. * `sql_log_update' Options for sql_log_update *Variable Name* `sql_log_update' *Variable Scope* Session *Dynamic Variable* Yes *Deprecated* 5.0, by `sql_log_bin' *Permitted Values * *Type* `boolean' This variable is deprecated, and is mapped to `sql_log_bin'. It is removed in MySQL 5.5. * `sql_mode' Options for sql-mode *Command-Line `--sql-mode=name' Format* *Option-File Format* `sql-mode' *Option Sets Yes, Variable* `sql_mode' *Variable Name* `sql_mode' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `set' *Default* `''' *Valid Values* `ALLOW_INVALID_DATES' `ANSI_QUOTES' `ERROR_FOR_DIVISION_BY_ZERO' `HIGH_NOT_PRECEDENCE' `IGNORE_SPACE' `NO_AUTO_CREATE_USER' `NO_AUTO_VALUE_ON_ZERO' `NO_BACKSLASH_ESCAPES' `NO_DIR_IN_CREATE' `NO_ENGINE_SUBSTITUTION' `NO_FIELD_OPTIONS' `NO_KEY_OPTIONS' `NO_TABLE_OPTIONS' `NO_UNSIGNED_SUBTRACTION' `NO_ZERO_DATE' `NO_ZERO_IN_DATE' `ONLY_FULL_GROUP_BY' `PAD_CHAR_TO_FULL_LENGTH' `PIPES_AS_CONCAT' `REAL_AS_FLOAT' `STRICT_ALL_TABLES' `STRICT_TRANS_TABLES' The current server SQL mode, which can be set dynamically. See *Note server-sql-mode::. * `sql_notes' If set to 1 (the default), warnings of `Note' level are recorded. If set to 0, `Note' warnings are suppressed. *Note `mysqldump': mysqldump. includes output to set this variable to 0 so that reloading the dump file does not produce warnings for events that do not affect the integrity of the reload operation. * `sql_quote_show_create' If set to 1 (the default), the server quotes identifiers for *Note `SHOW CREATE TABLE': show-create-table. and *Note `SHOW CREATE DATABASE': show-create-database. statements. If set to 0, quoting is disabled. This option is enabled by default so that replication works for identifiers that require quoting. See *Note show-create-table::, and *Note show-create-database::. * `sql_safe_updates' If set to 1, MySQL aborts *Note `UPDATE': update. or *Note `DELETE': delete. statements that do not use a key in the `WHERE' clause or a `LIMIT' clause. This makes it possible to catch *Note `UPDATE': update. or *Note `DELETE': delete. statements where keys are not used properly and that would probably change or delete a large number of rows. The default value is 0. * `sql_select_limit' Options for sql_select_limit *Variable Name* `sql_select_limit' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `numeric' The maximum number of rows to return from *Note `SELECT': select. statements. The default value for a new connection is the maximum number of rows that the server permits per table, which depends on the server configuration and may be affected if the server build was configured with `--with-big-tables'. Typical default values are (2^32)-1 or (2^64)-1. If you have changed the limit, the default value can be restored by assigning a value of `DEFAULT'. If a *Note `SELECT': select. has a `LIMIT' clause, the `LIMIT' takes precedence over the value of `sql_select_limit'. `sql_select_limit' does not apply to *Note `SELECT': select. statements executed within stored routines. It also does not apply to *Note `SELECT': select. statements that do not produce a result set to be returned to the client. These include *Note `SELECT': select. statements in subqueries, *Note `CREATE TABLE ... SELECT': create-table, and *Note `INSERT INTO ... SELECT': insert-select. * `sql_warnings' This variable controls whether single-row *Note `INSERT': insert. statements produce an information string if warnings occur. The default is 0. Set the value to 1 to produce an information string. * `ssl_ca' Options for ssl-ca *Version Introduced* 5.1.11 *Command-Line `--ssl-ca=name' Format* *Option-File Format* `ssl-ca' *Option Sets Yes, Variable* `ssl_ca' *Variable Name* `ssl_ca' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `file name' The path to a file with a list of trusted SSL CAs. This variable was added in MySQL 5.1.11. * `ssl_capath' Options for ssl-capath *Version Introduced* 5.1.11 *Command-Line `--ssl-capath=name' Format* *Option-File Format* `ssl-capath' *Option Sets Yes, Variable* `ssl_capath' *Variable Name* `ssl_capath' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `file name' The path to a directory that contains trusted SSL CA certificates in PEM format. This variable was added in MySQL 5.1.11. * `ssl_cert' Options for ssl-cert *Version Introduced* 5.1.11 *Command-Line `--ssl-cert=name' Format* *Option-File Format* `ssl-cert' *Option Sets Yes, Variable* `ssl_cert' *Variable Name* `ssl_cert' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `file name' The name of the SSL certificate file to use for establishing a secure connection. This variable was added in MySQL 5.1.11. * `ssl_cipher' Options for ssl-cipher *Version Introduced* 5.1.11 *Command-Line `--ssl-cipher=name' Format* *Option-File Format* `ssl-cipher' *Option Sets Yes, Variable* `ssl_cipher' *Variable Name* `ssl_cipher' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `file name' A list of permissible ciphers to use for SSL encryption. This variable was added in MySQL 5.1.11. * `ssl_key' Options for ssl-key *Version Introduced* 5.1.11 *Command-Line `--ssl-key=name' Format* *Option-File Format* `ssl-key' *Option Sets Yes, Variable* `ssl_key' *Variable Name* `ssl_key' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `string' The name of the SSL key file to use for establishing a secure connection. This variable was added in MySQL 5.1.11. * `storage_engine' Options for storage_engine *Variable Name* `storage_engine' *Variable Scope* Global, Session *Dynamic Variable* Yes The default storage engine (table type). To set the storage engine at server startup, use the `--default-storage-engine' option. See *Note server-options::. * `sync_frm' Options for sync_frm *Command-Line `--sync-frm' Format* *Option-File Format* `sync_frm' *Option Sets Yes, Variable* `sync_frm' *Variable Name* `sync_frm' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `boolean' *Default* `TRUE' If this variable is set to 1, when any nontemporary table is created its `.frm' file is synchronized to disk (using `fdatasync()'). This is slower but safer in case of a crash. The default is 1. * `system_time_zone' Options for system_time_zone *Variable Name* `system_time_zone' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `string' The server system time zone. When the server begins executing, it inherits a time zone setting from the machine defaults, possibly modified by the environment of the account used for running the server or the startup script. The value is used to set `system_time_zone'. Typically the time zone is specified by the `TZ' environment variable. It also can be specified using the `--timezone' option of the *Note `mysqld_safe': mysqld-safe. script. The `system_time_zone' variable differs from `time_zone'. Although they might have the same value, the latter variable is used to initialize the time zone for each client that connects. See *Note time-zone-support::. * `table_cache' Options for table_cache *Version Removed* 5.1.3 *Version Deprecated* 5.1.3 *Command-Line `--table_cache=#' Format* *Option-File Format* `table_cache' *Option Sets Yes, Variable* `table_cache' *Variable Name* `table_cache' *Variable Scope* Global *Dynamic Variable* Yes *Deprecated* 5.1.3, by `table_open_cache' *Permitted Values * *Type* `numeric' *Default* `64' *Range* `1-524288' This is the old name of `table_open_cache' before MySQL 5.1.3. From 5.1.3 on, use `table_open_cache' instead. * `table_definition_cache' Options for table_definition_cache *Version Introduced* 5.1.3 *Command-Line `--table_definition_cache=#' Format* *Option-File Format* `table_definition_cache' *Option Sets Yes, Variable* `table_definition_cache' *Variable Name* `table_definition_cache' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values (<= 5.1.24)* *Type* `numeric' *Default* `128' *Range* `1-524288' *Permitted Values (>= 5.1.25)* *Type* `numeric' *Default* `256' *Range* `256-524288' The number of table definitions that can be stored in the definition cache. If you use a large number of tables, you can create a large table definition cache to speed up opening of tables. The table definition cache takes less space and does not use file descriptors, unlike the normal table cache. This variable was added in MySQL 5.1.3. The minimum and default values are 1 and 128 before MySQL 5.1.25. The minimum and default are both 256 as of MySQL 5.1.25. * `table_lock_wait_timeout' Options for table_lock_wait_timeout *Command-Line `--table_lock_wait_timeout=#' Format* *Option-File Format* `table_lock_wait_timeout' *Option Sets Yes, Variable* `table_lock_wait_timeout' *Variable Name* `table_lock_wait_timeout' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `numeric' *Default* `50' *Range* `1-1073741824' This variable is unused. * `table_open_cache' Options for table_open_cache *Version Introduced* 5.1.3 *Command-Line `--table-open-cache=#' Format* *Option-File Format* `table_open_cache' *Variable Name* `table_open_cache' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `numeric' *Default* `64' *Range* `64-524288' The number of open tables for all threads. Increasing this value increases the number of file descriptors that *Note `mysqld': mysqld. requires. You can check whether you need to increase the table cache by checking the `Opened_tables' status variable. See *Note server-status-variables::. If the value of `Opened_tables' is large and you do not use *Note `FLUSH TABLES': flush. often (which just forces all tables to be closed and reopened), then you should increase the value of the `table_open_cache' variable. For more information about the table cache, see *Note table-cache::. Before MySQL 5.1.3, this variable is called `table_cache'. * `table_type' Options for table_type *Variable Name* `table_type' *Variable Scope* Global, Session *Dynamic Variable* Yes *Deprecated* 5.2.5, by `storage_engine' *Permitted Values * *Type* `enumeration' This variable is a synonym for `storage_engine'. In MySQL 5.1, `storage_engine' is the preferred name; `table_type' is deprecated and is removed in MySQL 5.5. * `thread_cache_size' Options for thread_cache_size *Command-Line `--thread_cache_size=#' Format* *Option-File Format* `thread_cache_size' *Option Sets Yes, Variable* `thread_cache_size' *Variable Name* `thread_cache_size' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `numeric' *Default* `0' *Range* `0-16384' How many threads the server should cache for reuse. When a client disconnects, the client's threads are put in the cache if there are fewer than `thread_cache_size' threads there. Requests for threads are satisfied by reusing threads taken from the cache if possible, and only when the cache is empty is a new thread created. This variable can be increased to improve performance if you have a lot of new connections. Normally, this does not provide a notable performance improvement if you have a good thread implementation. However, if your server sees hundreds of connections per second you should normally set `thread_cache_size' high enough so that most new connections use cached threads. By examining the difference between the `Connections' and `Threads_created' status variables, you can see how efficient the thread cache is. For details, see *Note server-status-variables::. * `thread_concurrency' Options for thread_concurrency *Command-Line `--thread_concurrency=#' Format* *Option-File Format* `thread_concurrency' *Option Sets Yes, Variable* `thread_concurrency' *Variable Name* `thread_concurrency' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `numeric' *Default* `10' *Range* `1-512' This variable is specific to Solaris systems, for which *Note `mysqld': mysqld. invokes the `thr_setconcurrency()' with the variable value. This function enables applications to give the threads system a hint about the desired number of threads that should be run at the same time. * `thread_handling' Options for thread_handling *Version Introduced* 5.1.17 *Command-Line `--thread_handling=name' Format* *Option-File Format* `thread_handling' *Option Sets Yes, Variable* `thread_handling' *Variable Name* `thread_handling' *Variable Scope* Global *Dynamic Variable* No The thread-handling model used by the server for connection threads. The permissible values are `no-threads' (the server uses a single thread) and `one-thread-per-connection' (the server uses one thread to handle each client connection). `no-threads' is useful for debugging under Linux; see MySQL Internals: Porting (http://forge.mysql.com/wiki/MySQL_Internals_Porting). This variable was added in MySQL 5.1.17 * `thread_stack' Options for thread_stack *Command-Line `--thread_stack=#' Format* *Option-File Format* `thread_stack' *Option Sets Yes, Variable* `thread_stack' *Variable Name* `thread_stack' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Platform Bit Size* `32' *Type* `numeric' *Default* `196608' *Range* `131072-4294967295' *Block Size* `1024' *Permitted Values * *Platform Bit Size* `64' *Type* `numeric' *Default* `262144' *Range* `131072-18446744073709547520' *Block Size* `1024' The stack size for each thread. Many of the limits detected by the `crash-me' test are dependent on this value. See *Note mysql-benchmarks::. The default of 192KB (256KB for 64-bit systems) is large enough for normal operation. If the thread stack size is too small, it limits the complexity of the SQL statements that the server can handle, the recursion depth of stored procedures, and other memory-consuming actions. * `time_format' This variable is unused. * `time_zone' Options for time_zone *Command-Line `--default_time_zone=string' Format* *Option-File Format* `default_time_zone' *Variable Name* `time_zone' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `string' The current time zone. This variable is used to initialize the time zone for each client that connects. By default, the initial value of this is `'SYSTEM'' (which means, `use the value of `system_time_zone''). The value can be specified explicitly at server startup with the `--default-time-zone' option. See *Note time-zone-support::. * `timed_mutexes' Options for timed_mutexes *Command-Line `--timed_mutexes' Format* *Option-File Format* `timed_mutexes' *Option Sets Yes, Variable* `timed_mutexes' *Variable Name* `timed_mutexes' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `boolean' *Default* `OFF' This variable controls whether `InnoDB' mutexes are timed. If this variable is set to 0 or `OFF' (the default), mutex timing is disabled. If the variable is set to 1 or `ON', mutex timing is enabled. With timing enabled, the `os_wait_times' value in the output from *Note `SHOW ENGINE INNODB MUTEX': show-engine. indicates the amount of time (in ms) spent in operating system waits. Otherwise, the value is 0. * `timestamp = {TIMESTAMP_VALUE | DEFAULT}' Set the time for this client. This is used to get the original timestamp if you use the binary log to restore rows. TIMESTAMP_VALUE should be a Unix epoch timestamp, not a MySQL timestamp. `SET timestamp' affects the value returned by `NOW()' but not by `SYSDATE()'. This means that timestamp settings in the binary log have no effect on invocations of `SYSDATE()'. The server can be started with the `--sysdate-is-now' option to cause `SYSDATE()' to be an alias for `NOW()', in which case `SET timestamp' affects both functions. * `tmp_table_size' Options for tmp_table_size *Command-Line `--tmp_table_size=#' Format* *Option-File Format* `tmp_table_size' *Option Sets Yes, Variable* `tmp_table_size' *Variable Name* `tmp_table_size' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `numeric' *Default* `system dependent' *Range* `1024-4294967295' The maximum size of internal in-memory temporary tables. (The actual limit is determined as the minimum of `tmp_table_size' and `max_heap_table_size'.) If an in-memory temporary table exceeds the limit, MySQL automatically converts it to an on-disk `MyISAM' table. Increase the value of `tmp_table_size' (and `max_heap_table_size' if necessary) if you do many advanced `GROUP BY' queries and you have lots of memory. This variable does not apply to user-created `MEMORY' tables. You can compare the number of internal on-disk temporary tables created to the total number of internal temporary tables created by comparing the values of the `Created_tmp_disk_tables' and `Created_tmp_tables' variables. See also *Note internal-temporary-tables::. * `tmpdir' Options for tmpdir *Command-Line `--tmpdir=path' Format* ** `-t' *Option-File Format* `tmpdir' *Option Sets Yes, Variable* `tmpdir' *Variable Name* `tmpdir' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `file name' The directory used for temporary files and temporary tables. This variable can be set to a list of several paths that are used in round-robin fashion. Paths should be separated by colon characters (``:'') on Unix and semicolon characters (``;'') on Windows, NetWare, and OS/2. The multiple-directory feature can be used to spread the load between several physical disks. If the MySQL server is acting as a replication slave, you should not set `tmpdir' to point to a directory on a memory-based file system or to a directory that is cleared when the server host restarts. A replication slave needs some of its temporary files to survive a machine restart so that it can replicate temporary tables or *Note `LOAD DATA INFILE': load-data. operations. If files in the temporary file directory are lost when the server restarts, replication fails. You can set the slave's temporary directory using the `slave_load_tmpdir' variable. In that case, the slave will not use the general `tmpdir' value and you can set `tmpdir' to a nonpermanent location. * `transaction_alloc_block_size' Options for transaction_alloc_block_size *Command-Line `--transaction_alloc_block_size=#' Format* *Option-File Format* `transaction_alloc_block_size' *Option Sets Yes, Variable* `transaction_alloc_block_size' *Variable Name* `transaction_alloc_block_size' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Platform Bit Size* `32' *Type* `numeric' *Default* `8192' *Range* `1024-4294967295' *Block Size* `1024' *Permitted Values * *Platform Bit Size* `64' *Type* `numeric' *Default* `8192' *Range* `1024-18446744073709547520' *Block Size* `1024' The amount in bytes by which to increase a per-transaction memory pool which needs memory. See the description of `transaction_prealloc_size'. * `transaction_allow_batching' Options for transaction_allow_batching *Version Introduced* 5.1.23-ndb-6.3.7 *Variable Name* `transaction_allow_batching' *Variable Scope* Session *Dynamic Variable* Yes *Permitted Values * *Type* `boolean' *Default* `FALSE' When set to `1' or `ON', this variable enables batching of statements within the same transaction. To use this variable, `autocommit' must first be disabled by setting it to `0' or `OFF'; otherwise, setting `transaction_allow_batching' has no effect. This variable was added in MySQL Cluster NDB 6.3.7, and is currently supported for MySQL Cluster _only_. * `transaction_prealloc_size' Options for transaction_prealloc_size *Command-Line `--transaction_prealloc_size=#' Format* *Option-File Format* `transaction_prealloc_size' *Option Sets Yes, Variable* `transaction_prealloc_size' *Variable Name* `transaction_prealloc_size' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Platform Bit Size* `32' *Type* `numeric' *Default* `4096' *Range* `1024-4294967295' *Block Size* `1024' *Permitted Values * *Platform Bit Size* `64' *Type* `numeric' *Default* `4096' *Range* `1024-18446744073709547520' *Block Size* `1024' There is a per-transaction memory pool from which various transaction-related allocations take memory. The initial size of the pool in bytes is `transaction_prealloc_size'. For every allocation that cannot be satisfied from the pool because it has insufficient memory available, the pool is increased by `transaction_alloc_block_size' bytes. When the transaction ends, the pool is truncated to `transaction_prealloc_size' bytes. By making `transaction_prealloc_size' sufficiently large to contain all statements within a single transaction, you can avoid many `malloc()' calls. * `tx_isolation' Options for tx_isolation *Variable Name* `tx_isolation' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `enumeration' *Default* `REPEATABLE-READ' *Valid Values* `READ-UNCOMMITTED' `READ-COMMITTED' `REPEATABLE-READ' ` SERIALIZABLE ' The default transaction isolation level. Defaults to `REPEATABLE-READ'. This variable is set by the *Note `SET TRANSACTION ISOLATION LEVEL': set-transaction. statement. See *Note set-transaction::. If you set `tx_isolation' directly to an isolation level name that contains a space, the name should be enclosed within quotation marks, with the space replaced by a dash. For example: SET tx_isolation = 'READ-COMMITTED'; Any unique prefix of a valid value may be used to set the value of this variable. The default transactional isolation level can also be set at startup using the `--transaction-isolation' server option. * `unique_checks' Options for unique_checks *Variable Name* `unique_checks' *Variable Scope* Session *Dynamic Variable* Yes *Permitted Values * *Type* `boolean' *Default* `1' If set to 1 (the default), uniqueness checks for secondary indexes in `InnoDB' tables are performed. If set to 0, storage engines are permitted to assume that duplicate keys are not present in input data. If you know for certain that your data does not contain uniqueness violations, you can set this to 0 to speed up large table imports to `InnoDB'. Note that setting this variable to 0 does not _require_ storage engines to ignore duplicate keys. An engine is still permitted to check for them and issue duplicate-key errors if it detects them. * `updatable_views_with_limit' Options for updatable_views_with_limit *Command-Line `--updatable_views_with_limit=#' Format* *Option-File Format* `updatable_views_with_limit' *Option Sets Yes, Variable* `updatable_views_with_limit' *Variable Name* `updatable_views_with_limit' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `boolean' *Default* `1' This variable controls whether updates to a view can be made when the view does not contain all columns of the primary key defined in the underlying table, if the update statement contains a `LIMIT' clause. (Such updates often are generated by GUI tools.) An update is an *Note `UPDATE': update. or *Note `DELETE': delete. statement. Primary key here means a `PRIMARY KEY', or a `UNIQUE' index in which no column can contain `NULL'. The variable can have two values: * `1' or `YES': Issue a warning only (not an error message). This is the default value. * `0' or `NO': Prohibit the update. * `version' The version number for the server. The value might also include a suffix indicating server build or configuration information. `-log' indicates that one or more of the general log, slow query log, or binary log are enabled. `-debug' indicates that the server was built with debugging support enabled. * `version_comment' Options for version_comment *Variable Name* `version_comment' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `string' The `configure' script has a `--with-comment' option that permits a comment to be specified when building MySQL. This variable contains the value of that comment. * `version_compile_machine' Options for version_compile_machine *Variable Name* `version_compile_machine' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `string' The type of machine or architecture on which MySQL was built. * `version_compile_os' Options for version_compile_os *Variable Name* `version_compile_os' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `string' The type of operating system on which MySQL was built. * `wait_timeout' Options for wait_timeout *Command-Line `--wait_timeout=#' Format* *Option-File Format* `wait_timeout' *Option Sets Yes, Variable* `wait_timeout' *Variable Name* `wait_timeout' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `numeric' *Default* `28800' *Range* `1-31536000' *Permitted Values * *Type* (windows) `numeric' *Default* `28800' *Range* `1-2147483' The number of seconds the server waits for activity on a noninteractive connection before closing it. This timeout applies only to TCP/IP and Unix socket file connections, not to connections made using named pipes, or shared memory. On thread startup, the session `wait_timeout' value is initialized from the global `wait_timeout' value or from the global `interactive_timeout' value, depending on the type of client (as defined by the `CLIENT_INTERACTIVE' connect option to *Note `mysql_real_connect()': mysql-real-connect.). See also `interactive_timeout'. * `warning_count' The number of errors, warnings, and notes that resulted from the last statement that generated messages. This variable is read only. See *Note show-warnings::.  File: manual.info, Node: using-system-variables, Next: server-status-variables, Prev: server-system-variables, Up: mysqld-server 6.1.4 Using System Variables ---------------------------- * Menu: * structured-system-variables:: Structured System Variables * dynamic-system-variables:: Dynamic System Variables The MySQL server maintains many system variables that indicate how it is configured. *Note server-system-variables::, describes the meaning of these variables. Each system variable has a default value. System variables can be set at server startup using options on the command line or in an option file. Most of them can be changed dynamically while the server is running by means of the *Note `SET': set-option. statement, which enables you to modify operation of the server without having to stop and restart it. You can refer to system variable values in expressions. The server maintains two kinds of system variables. Global variables affect the overall operation of the server. Session variables affect its operation for individual client connections. A given system variable can have both a global and a session value. Global and session system variables are related as follows: * When the server starts, it initializes all global variables to their default values. These defaults can be changed by options specified on the command line or in an option file. (See *Note program-options::.) * The server also maintains a set of session variables for each client that connects. The client's session variables are initialized at connect time using the current values of the corresponding global variables. For example, the client's SQL mode is controlled by the session `sql_mode' value, which is initialized when the client connects to the value of the global `sql_mode' value. System variable values can be set globally at server startup by using options on the command line or in an option file. When you use a startup option to set a variable that takes a numeric value, the value can be given with a suffix of `K', `M', or `G' (either uppercase or lowercase) to indicate a multiplier of 1024, 1024^2 or 1024^3; that is, units of kilobytes, megabytes, or gigabytes, respectively. Thus, the following command starts the server with a query cache size of 16 megabytes and a maximum packet size of one gigabyte: mysqld --query_cache_size=16M --max_allowed_packet=1G Within an option file, those variables are set like this: [mysqld] query_cache_size=16M max_allowed_packet=1G The lettercase of suffix letters does not matter; `16M' and `16m' are equivalent, as are `1G' and `1g'. If you want to restrict the maximum value to which a system variable can be set at runtime with the *Note `SET': set-option. statement, you can specify this maximum by using an option of the form `--maximum-VAR_NAME=VALUE' at server startup. For example, to prevent the value of `query_cache_size' from being increased to more than 32MB at runtime, use the option `--maximum-query_cache_size=32M'. Many system variables are dynamic and can be changed while the server runs by using the *Note `SET': set-option. statement. For a list, see *Note dynamic-system-variables::. To change a system variable with *Note `SET': set-option, refer to it as VAR_NAME, optionally preceded by a modifier: * To indicate explicitly that a variable is a global variable, precede its name by `GLOBAL' or `@@global.'. The `SUPER' privilege is required to set global variables. * To indicate explicitly that a variable is a session variable, precede its name by `SESSION', `@@session.', or `@@'. Setting a session variable requires no special privilege, but a client can change only its own session variables, not those of any other client. * `LOCAL' and `@@local.' are synonyms for `SESSION' and `@@session.'. * If no modifier is present, *Note `SET': set-option. changes the session variable. A *Note `SET': set-option. statement can contain multiple variable assignments, separated by commas. If you set several system variables, the most recent `GLOBAL' or `SESSION' modifier in the statement is used for following variables that have no modifier specified. Examples: SET sort_buffer_size=10000; SET @@local.sort_buffer_size=10000; SET GLOBAL sort_buffer_size=1000000, SESSION sort_buffer_size=1000000; SET @@sort_buffer_size=1000000; SET @@global.sort_buffer_size=1000000, @@local.sort_buffer_size=1000000; The `@@VAR_NAME' syntax for system variables is supported for compatibility with some other database systems. If you change a session system variable, the value remains in effect until your session ends or until you change the variable to a different value. The change is not visible to other clients. If you change a global system variable, the value is remembered and used for new connections until the server restarts. (To make a global system variable setting permanent, you should set it in an option file.) The change is visible to any client that accesses that global variable. However, the change affects the corresponding session variable only for clients that connect after the change. The global variable change does not affect the session variable for any client that is currently connected (not even that of the client that issues the *Note `SET GLOBAL': set-option. statement). To prevent incorrect usage, MySQL produces an error if you use *Note `SET GLOBAL': set-option. with a variable that can only be used with *Note `SET SESSION': set-option. or if you do not specify `GLOBAL' (or `@@global.') when setting a global variable. To set a `SESSION' variable to the `GLOBAL' value or a `GLOBAL' value to the compiled-in MySQL default value, use the `DEFAULT' keyword. For example, the following two statements are identical in setting the session value of `max_join_size' to the global value: SET max_join_size=DEFAULT; SET @@session.max_join_size=@@global.max_join_size; Not all system variables can be set to `DEFAULT'. In such cases, use of `DEFAULT' results in an error. You can refer to the values of specific global or session system variables in expressions by using one of the `@@'-modifiers. For example, you can retrieve values in a *Note `SELECT': select. statement like this: SELECT @@global.sql_mode, @@session.sql_mode, @@sql_mode; When you refer to a system variable in an expression as `@@VAR_NAME' (that is, when you do not specify `@@global.' or `@@session.'), MySQL returns the session value if it exists and the global value otherwise. (This differs from `SET @@VAR_NAME = VALUE', which always refers to the session value.) *Note*: Some variables displayed by `SHOW VARIABLES' may not be available using `SELECT @@VAR_NAME' syntax; an `Unknown system variable' occurs. As a workaround in such cases, you can use `SHOW VARIABLES LIKE 'VAR_NAME''. Suffixes for specifying a value multiplier can be used when setting a variable at server startup, but not to set the value with *Note `SET': set-option. at runtime. On the other hand, with *Note `SET': set-option. you can assign a variable's value using an expression, which is not true when you set a variable at server startup. For example, the first of the following lines is legal at server startup, but the second is not: shell> mysql --max_allowed_packet=16M shell> mysql --max_allowed_packet=16*1024*1024 Conversely, the second of the following lines is legal at runtime, but the first is not: mysql> SET GLOBAL max_allowed_packet=16M; mysql> SET GLOBAL max_allowed_packet=16*1024*1024; *Note*: Some system variables can be enabled with the *Note `SET': set-option. statement by setting them to `ON' or `1', or disabled by setting them to `OFF' or `0'. However, to set such a variable on the command line or in an option file, you must set it to `1' or `0'; setting it to `ON' or `OFF' will not work. For example, on the command line, `--delay_key_write=1' works but `--delay_key_write=ON' does not. To display system variable names and values, use the *Note `SHOW VARIABLES': show-variables. statement: mysql> SHOW VARIABLES; +---------------------------------+-----------------------------------+ | Variable_name | Value | +---------------------------------+-----------------------------------+ | auto_increment_increment | 1 | | auto_increment_offset | 1 | | automatic_sp_privileges | ON | | back_log | 50 | | basedir | /home/mysql/ | | binlog_cache_size | 32768 | | bulk_insert_buffer_size | 8388608 | | character_set_client | latin1 | | character_set_connection | latin1 | | character_set_database | latin1 | | character_set_results | latin1 | | character_set_server | latin1 | | character_set_system | utf8 | | character_sets_dir | /home/mysql/share/mysql/charsets/ | | collation_connection | latin1_swedish_ci | | collation_database | latin1_swedish_ci | | collation_server | latin1_swedish_ci | ... | innodb_additional_mem_pool_size | 1048576 | | innodb_autoextend_increment | 8 | | innodb_buffer_pool_size | 8388608 | | innodb_checksums | ON | | innodb_commit_concurrency | 0 | | innodb_concurrency_tickets | 500 | | innodb_data_file_path | ibdata1:10M:autoextend | | innodb_data_home_dir | | ... | version | 5.1.6-alpha-log | | version_comment | Source distribution | | version_compile_machine | i686 | | version_compile_os | suse-linux | | wait_timeout | 28800 | +---------------------------------+-----------------------------------+ With a `LIKE' clause, the statement displays only those variables that match the pattern. To obtain a specific variable name, use a `LIKE' clause as shown: SHOW VARIABLES LIKE 'max_join_size'; SHOW SESSION VARIABLES LIKE 'max_join_size'; To get a list of variables whose name match a pattern, use the ``%'' wildcard character in a `LIKE' clause: SHOW VARIABLES LIKE '%size%'; SHOW GLOBAL VARIABLES LIKE '%size%'; Wildcard characters can be used in any position within the pattern to be matched. Strictly speaking, because ``_'' is a wildcard that matches any single character, you should escape it as ``\_'' to match it literally. In practice, this is rarely necessary. For *Note `SHOW VARIABLES': show-variables, if you specify neither `GLOBAL' nor `SESSION', MySQL returns `SESSION' values. The reason for requiring the `GLOBAL' keyword when setting `GLOBAL'-only variables but not when retrieving them is to prevent problems in the future. If we were to remove a `SESSION' variable that has the same name as a `GLOBAL' variable, a client with the `SUPER' privilege might accidentally change the `GLOBAL' variable rather than just the `SESSION' variable for its own connection. If we add a `SESSION' variable with the same name as a `GLOBAL' variable, a client that intends to change the `GLOBAL' variable might find only its own `SESSION' variable changed.  File: manual.info, Node: structured-system-variables, Next: dynamic-system-variables, Prev: using-system-variables, Up: using-system-variables 6.1.4.1 Structured System Variables ................................... A structured variable differs from a regular system variable in two respects: * Its value is a structure with components that specify server parameters considered to be closely related. * There might be several instances of a given type of structured variable. Each one has a different name and refers to a different resource maintained by the server. MySQL 5.1 supports one structured variable type, which specifies parameters governing the operation of key caches. A key cache structured variable has these components: * `key_buffer_size' * `key_cache_block_size' * `key_cache_division_limit' * `key_cache_age_threshold' This section describes the syntax for referring to structured variables. Key cache variables are used for syntax examples, but specific details about how key caches operate are found elsewhere, in *Note myisam-key-cache::. To refer to a component of a structured variable instance, you can use a compound name in INSTANCE_NAME.COMPONENT_NAME format. Examples: hot_cache.key_buffer_size hot_cache.key_cache_block_size cold_cache.key_cache_block_size For each structured system variable, an instance with the name of `default' is always predefined. If you refer to a component of a structured variable without any instance name, the `default' instance is used. Thus, `default.key_buffer_size' and `key_buffer_size' both refer to the same system variable. Structured variable instances and components follow these naming rules: * For a given type of structured variable, each instance must have a name that is unique _within_ variables of that type. However, instance names need not be unique _across_ structured variable types. For example, each structured variable has an instance named `default', so `default' is not unique across variable types. * The names of the components of each structured variable type must be unique across all system variable names. If this were not true (that is, if two different types of structured variables could share component member names), it would not be clear which default structured variable to use for references to member names that are not qualified by an instance name. * If a structured variable instance name is not legal as an unquoted identifier, refer to it as a quoted identifier using backticks. For example, `hot-cache' is not legal, but ``hot-cache`' is. * `global', `session', and `local' are not legal instance names. This avoids a conflict with notation such as `@@global.VAR_NAME' for referring to nonstructured system variables. Currently, the first two rules have no possibility of being violated because the only structured variable type is the one for key caches. These rules will assume greater significance if some other type of structured variable is created in the future. With one exception, you can refer to structured variable components using compound names in any context where simple variable names can occur. For example, you can assign a value to a structured variable using a command-line option: shell> mysqld --hot_cache.key_buffer_size=64K In an option file, use this syntax: [mysqld] hot_cache.key_buffer_size=64K If you start the server with this option, it creates a key cache named `hot_cache' with a size of 64KB in addition to the default key cache that has a default size of 8MB. Suppose that you start the server as follows: shell> mysqld --key_buffer_size=256K \ --extra_cache.key_buffer_size=128K \ --extra_cache.key_cache_block_size=2048 In this case, the server sets the size of the default key cache to 256KB. (You could also have written `--default.key_buffer_size=256K'.) In addition, the server creates a second key cache named `extra_cache' that has a size of 128KB, with the size of block buffers for caching table index blocks set to 2048 bytes. The following example starts the server with three different key caches having sizes in a 3:1:1 ratio: shell> mysqld --key_buffer_size=6M \ --hot_cache.key_buffer_size=2M \ --cold_cache.key_buffer_size=2M Structured variable values may be set and retrieved at runtime as well. For example, to set a key cache named `hot_cache' to a size of 10MB, use either of these statements: mysql> SET GLOBAL hot_cache.key_buffer_size = 10*1024*1024; mysql> SET @@global.hot_cache.key_buffer_size = 10*1024*1024; To retrieve the cache size, do this: mysql> SELECT @@global.hot_cache.key_buffer_size; However, the following statement does not work. The variable is not interpreted as a compound name, but as a simple string for a `LIKE' pattern-matching operation: mysql> SHOW GLOBAL VARIABLES LIKE 'hot_cache.key_buffer_size'; This is the exception to being able to use structured variable names anywhere a simple variable name may occur.  File: manual.info, Node: dynamic-system-variables, Prev: structured-system-variables, Up: using-system-variables 6.1.4.2 Dynamic System Variables ................................ Many server system variables are dynamic and can be set at runtime using *Note `SET GLOBAL': set-option. or *Note `SET SESSION': set-option. You can also obtain their values using *Note `SELECT': select. See *Note using-system-variables::. The following table shows the full list of all dynamic system variables. The last column indicates for each variable whether `GLOBAL' or `SESSION' (or both) apply. The table also lists session options that can be set with the *Note `SET': set-option. statement. *Note server-system-variables::, discusses these options. Variables that have a type of `string' take a string value. Variables that have a type of `numeric' take a numeric value. Variables that have a type of `boolean' can be set to 0, 1, `ON' or `OFF'. (If you set them on the command line or in an option file, use the numeric values.) Variables that are marked as `enumeration' normally should be set to one of the available values for the variable, but can also be set to the number that corresponds to the desired enumeration value. For enumerated system variables, the first enumeration value corresponds to 0. This differs from *Note `ENUM': enum. columns, for which the first enumeration value corresponds to 1. *Dynamic Variable Summary* Variable Name Variable Type Variable Scope `auto_increment_increment' numeric `GLOBAL' | `SESSION' `auto_increment_offset' numeric `GLOBAL' | `SESSION' `autocommit' boolean `SESSION' `automatic_sp_privileges' boolean `GLOBAL' `big_tables' boolean `SESSION' `binlog_cache_size' numeric `GLOBAL' `binlog_direct_non_transactional_updates'boolean `GLOBAL' | `SESSION' `binlog_format' enumeration `GLOBAL' | `SESSION' `bulk_insert_buffer_size' numeric `GLOBAL' | `SESSION' `character_set_client' string `GLOBAL' | `SESSION' `character_set_connection' string `GLOBAL' | `SESSION' `character_set_database' string `GLOBAL' | `SESSION' `character_set_filesystem' string `GLOBAL' | `SESSION' `character_set_results' string `GLOBAL' | `SESSION' `character_set_server' string `GLOBAL' | `SESSION' `collation_connection' string `GLOBAL' | `SESSION' `collation_database' string `GLOBAL' | `SESSION' `collation_server' string `GLOBAL' | `SESSION' `completion_type' numeric `GLOBAL' | `SESSION' `concurrent_insert' boolean `GLOBAL' `connect_timeout' numeric `GLOBAL' `debug' string `GLOBAL' | `SESSION' `debug_sync' string `GLOBAL' | `SESSION' `default-storage-engine' enumeration `GLOBAL' | `SESSION' `default_week_format' numeric `GLOBAL' | `SESSION' `delay_key_write' enumeration `GLOBAL' `delayed_insert_limit' numeric `GLOBAL' `delayed_insert_timeout' numeric `GLOBAL' `delayed_queue_size' numeric `GLOBAL' `div_precision_increment' numeric `GLOBAL' | `SESSION' `engine_condition_pushdown' boolean `GLOBAL' | `SESSION' `event_scheduler' enumeration `GLOBAL' `expire_logs_days' numeric `GLOBAL' `flush' boolean `GLOBAL' `flush_time' numeric `GLOBAL' `foreign_key_checks' boolean `SESSION' `ft_boolean_syntax' string `GLOBAL' `general_log' boolean `GLOBAL' `general_log_file' filename `GLOBAL' `group_concat_max_len' numeric `GLOBAL' | `SESSION' `identity' numeric `SESSION' `init_connect' string `GLOBAL' `init_slave' string `GLOBAL' `innodb_adaptive_flushing' boolean `GLOBAL' `innodb_autoextend_increment' numeric `GLOBAL' `innodb_change_buffering' enumeration `GLOBAL' `innodb_commit_concurrency' numeric `GLOBAL' `innodb_concurrency_tickets' numeric `GLOBAL' `innodb_fast_shutdown' numeric `GLOBAL' `innodb_file_format' string `GLOBAL' `innodb_file_format_check' string `GLOBAL' `innodb_flush_log_at_trx_commit'numeric `GLOBAL' `innodb_lock_wait_timeout' numeric `GLOBAL' | `SESSION' `innodb_max_dirty_pages_pct' numeric `GLOBAL' `innodb_max_purge_lag' numeric `GLOBAL' `innodb_old_blocks_pct' numeric `GLOBAL' `innodb_old_blocks_time' numeric `GLOBAL' `innodb_read_ahead_threshold' numeric `GLOBAL' `innodb_replication_delay' numeric `GLOBAL' `innodb_spin_wait_delay' numeric `GLOBAL' `innodb_stats_on_metadata' boolean `GLOBAL' `innodb_stats_sample_pages' numeric `GLOBAL' `innodb_strict_mode' boolean `GLOBAL' | `SESSION' `innodb_support_xa' boolean `GLOBAL' | `SESSION' `innodb_sync_spin_loops' numeric `GLOBAL' `innodb_table_locks' boolean `GLOBAL' | `SESSION' `innodb_thread_concurrency' numeric `GLOBAL' `innodb_thread_sleep_delay' numeric `GLOBAL' `innodb_use_legacy_cardinality_algorithm'boolean `GLOBAL' `insert_id' numeric `SESSION' `interactive_timeout' numeric `GLOBAL' | `SESSION' `join_buffer_size' numeric `GLOBAL' | `SESSION' `keep_files_on_create' boolean `GLOBAL' | `SESSION' `key_buffer_size' numeric `GLOBAL' `key_cache_age_threshold' numeric `GLOBAL' `key_cache_block_size' numeric `GLOBAL' `key_cache_division_limit' numeric `GLOBAL' `last_insert_id' numeric `SESSION' `lc_time_names' string `GLOBAL' | `SESSION' `local_infile' boolean `GLOBAL' `log' string `GLOBAL' `log_bin_trust_function_creators'boolean `GLOBAL' `log_bin_trust_routine_creators'boolean `GLOBAL' `log_output' set `GLOBAL' `log_queries_not_using_indexes'boolean `GLOBAL' `log_slow_queries' boolean `GLOBAL' `log_warnings' numeric `GLOBAL' | `SESSION' `long_query_time' numeric `GLOBAL' | `SESSION' `low_priority_updates' boolean `GLOBAL' | `SESSION' `max_allowed_packet' numeric `GLOBAL' `max_binlog_cache_size' numeric `GLOBAL' `max_binlog_size' numeric `GLOBAL' `max_connect_errors' numeric `GLOBAL' `max_connections' numeric `GLOBAL' `max_delayed_threads' numeric `GLOBAL' | `SESSION' `max_error_count' numeric `GLOBAL' | `SESSION' `max_heap_table_size' numeric `GLOBAL' | `SESSION' `max_insert_delayed_threads' numeric `GLOBAL' | `SESSION' `max_join_size' numeric `GLOBAL' | `SESSION' `max_length_for_sort_data' numeric `GLOBAL' | `SESSION' `max_prepared_stmt_count' numeric `GLOBAL' `max_relay_log_size' numeric `GLOBAL' `max_seeks_for_key' numeric `GLOBAL' | `SESSION' `max_sort_length' numeric `GLOBAL' | `SESSION' `max_sp_recursion_depth' numeric `GLOBAL' | `SESSION' `max_tmp_tables' numeric `GLOBAL' | `SESSION' `max_user_connections' numeric `GLOBAL' | `SESSION' `max_write_lock_count' numeric `GLOBAL' `min_examined_row_limit' numeric `GLOBAL' | `SESSION' `multi_range_count' numeric `GLOBAL' | `SESSION' `myisam_data_pointer_size' numeric `GLOBAL' `myisam_max_sort_file_size' numeric `GLOBAL' `myisam_repair_threads' numeric `GLOBAL' | `SESSION' `myisam_sort_buffer_size' numeric `GLOBAL' | `SESSION' `myisam_stats_method' enumeration `GLOBAL' | `SESSION' `myisam_use_mmap' boolean `GLOBAL' `ndb_autoincrement_prefetch_sz'numeric `GLOBAL' | `SESSION' `ndb_blob_read_batch_bytes' numeric `GLOBAL' | `SESSION' `ndb_blob_write_batch_bytes' numeric `GLOBAL' | `SESSION' `ndb_cache_check_time' numeric `GLOBAL' `ndb_extra_logging' numeric `GLOBAL' `ndb_force_send' boolean `GLOBAL' | `SESSION' `ndb_log_bin' boolean `GLOBAL' | `SESSION' `ndb_log_binlog_index' boolean `GLOBAL' `ndb_log_empty_epochs' boolean `GLOBAL' `ndb_log_update_as_write' boolean `GLOBAL' `ndb_log_updated_only' boolean `GLOBAL' `ndb_optimization_delay' numeric `GLOBAL' `ndb_table_no_logging' boolean `SESSION' `ndb_table_temporary' boolean `SESSION' `ndb_use_exact_count' boolean `GLOBAL' | `SESSION' `ndb_use_transactions' boolean `GLOBAL' | `SESSION' `ndbinfo_max_bytes' numeric `GLOBAL' | `SESSION' `ndbinfo_max_rows' numeric `GLOBAL' | `SESSION' `ndbinfo_show_hidden' boolean `GLOBAL' | `SESSION' `ndbinfo_table_prefix' string `GLOBAL' | `SESSION' `net_buffer_length' numeric `GLOBAL' | `SESSION' `net_read_timeout' numeric `GLOBAL' | `SESSION' `net_retry_count' numeric `GLOBAL' | `SESSION' `net_write_timeout' numeric `GLOBAL' | `SESSION' `new' boolean `GLOBAL' | `SESSION' `old_alter_table' boolean `GLOBAL' | `SESSION' `old_passwords' boolean `GLOBAL' | `SESSION' `optimizer_prune_level' boolean `GLOBAL' | `SESSION' `optimizer_search_depth' numeric `GLOBAL' | `SESSION' `optimizer_switch' set `GLOBAL' | `SESSION' `preload_buffer_size' numeric `GLOBAL' | `SESSION' `profiling' boolean `SESSION' `profiling_history_size' numeric `GLOBAL' | `SESSION' `pseudo_thread_id' numeric `SESSION' `query_alloc_block_size' numeric `GLOBAL' | `SESSION' `query_cache_limit' numeric `GLOBAL' `query_cache_min_res_unit' numeric `GLOBAL' `query_cache_size' numeric `GLOBAL' `query_cache_type' enumeration `GLOBAL' | `SESSION' `query_cache_wlock_invalidate'boolean `GLOBAL' | `SESSION' `query_prealloc_size' numeric `GLOBAL' | `SESSION' `rand_seed1' numeric `SESSION' `rand_seed2' numeric `SESSION' `range_alloc_block_size' numeric `GLOBAL' | `SESSION' `read_buffer_size' numeric `GLOBAL' | `SESSION' `read_only' numeric `GLOBAL' `read_rnd_buffer_size' numeric `GLOBAL' | `SESSION' `relay_log_purge' boolean `GLOBAL' `rpl_recovery_rank' numeric `GLOBAL' `safe_show_database' boolean `GLOBAL' `secure_auth' boolean `GLOBAL' `server_id' numeric `GLOBAL' `slave_allow_batching' boolean `GLOBAL' `slave_compressed_protocol' boolean `GLOBAL' `slave_exec_mode' enumeration `GLOBAL' `slave_net_timeout' numeric `GLOBAL' `slave_transaction_retries' numeric `GLOBAL' `slow_launch_time' numeric `GLOBAL' `slow_query_log' boolean `GLOBAL' `slow_query_log_file' filename `GLOBAL' `sort_buffer_size' numeric `GLOBAL' | `SESSION' `sql_auto_is_null' boolean `SESSION' `sql_big_selects' boolean `SESSION' `sql_big_tables' boolean `SESSION' `sql_buffer_result' boolean `SESSION' `sql_log_bin' boolean `SESSION' `sql_log_off' boolean `SESSION' `sql_log_update' boolean `SESSION' `sql_low_priority_updates' boolean `GLOBAL' | `SESSION' `sql_max_join_size' numeric `GLOBAL' | `SESSION' `sql_mode' set `GLOBAL' | `SESSION' `sql_notes' boolean `SESSION' `sql_quote_show_create' boolean `SESSION' `sql_safe_updates' boolean `SESSION' `sql_select_limit' numeric `GLOBAL' | `SESSION' `sql_slave_skip_counter' numeric `GLOBAL' `sql_warnings' boolean `SESSION' `storage_engine' enumeration `GLOBAL' | `SESSION' `sync_binlog' numeric `GLOBAL' `sync_frm' boolean `GLOBAL' `table_cache' numeric `GLOBAL' `table_definition_cache' numeric `GLOBAL' `table_lock_wait_timeout' numeric `GLOBAL' `table_open_cache' numeric `GLOBAL' `table_type' enumeration `GLOBAL' | `SESSION' `thread_cache_size' numeric `GLOBAL' `time_zone' string `GLOBAL' | `SESSION' `timed_mutexes' boolean `GLOBAL' `timestamp' numeric `SESSION' `tmp_table_size' numeric `GLOBAL' | `SESSION' `transaction_alloc_block_size'numeric `GLOBAL' | `SESSION' `transaction_allow_batching' boolean `SESSION' `transaction_prealloc_size' numeric `GLOBAL' | `SESSION' `tx_isolation' enumeration `GLOBAL' | `SESSION' `unique_checks' boolean `SESSION' `updatable_views_with_limit' boolean `GLOBAL' | `SESSION' `wait_timeout' numeric `GLOBAL' | `SESSION'  File: manual.info, Node: server-status-variables, Next: server-sql-mode, Prev: using-system-variables, Up: mysqld-server 6.1.5 Server Status Variables ----------------------------- The server maintains many status variables that provide information about its operation. You can view these variables and their values by using the `SHOW [GLOBAL | SESSION] STATUS' statement (see *Note show-status::). The optional `GLOBAL' keyword aggregates the values over all connections, and `SESSION' shows the values for the current connection. mysql> SHOW GLOBAL STATUS; +-----------------------------------+------------+ | Variable_name | Value | +-----------------------------------+------------+ | Aborted_clients | 0 | | Aborted_connects | 0 | | Bytes_received | 155372598 | | Bytes_sent | 1176560426 | ... | Connections | 30023 | | Created_tmp_disk_tables | 0 | | Created_tmp_files | 3 | | Created_tmp_tables | 2 | ... | Threads_created | 217 | | Threads_running | 88 | | Uptime | 1389872 | +-----------------------------------+------------+ The following table lists all available server status variables: *Status Variable Summary* Variable Name Variable Type Variable Scope `Aborted_clients' numeric `GLOBAL' `Aborted_connects' numeric `GLOBAL' `Binlog_cache_disk_use' numeric `GLOBAL' `Binlog_cache_use' numeric `GLOBAL' `Bytes_received' numeric `GLOBAL' | `SESSION' `Bytes_sent' numeric `GLOBAL' | `SESSION' `Com_admin_commands' numeric `GLOBAL' | `SESSION' `Com_alter_db' numeric `GLOBAL' | `SESSION' `Com_alter_db_upgrade' numeric `GLOBAL' | `SESSION' `Com_alter_event' numeric `GLOBAL' | `SESSION' `Com_alter_function' numeric `GLOBAL' | `SESSION' `Com_alter_procedure' numeric `GLOBAL' | `SESSION' `Com_alter_server' numeric `GLOBAL' | `SESSION' `Com_alter_table' numeric `GLOBAL' | `SESSION' `Com_alter_tablespace' numeric `GLOBAL' | `SESSION' `Com_analyze' numeric `GLOBAL' | `SESSION' `Com_assign_to_keycache' numeric `GLOBAL' | `SESSION' `Com_backup_table' numeric `GLOBAL' | `SESSION' `Com_begin' numeric `GLOBAL' | `SESSION' `Com_binlog' numeric `GLOBAL' | `SESSION' `Com_call_procedure' numeric `GLOBAL' | `SESSION' `Com_change_db' numeric `GLOBAL' | `SESSION' `Com_change_master' numeric `GLOBAL' | `SESSION' `Com_check' numeric `GLOBAL' | `SESSION' `Com_checksum' numeric `GLOBAL' | `SESSION' `Com_commit' numeric `GLOBAL' | `SESSION' `Com_create_db' numeric `GLOBAL' | `SESSION' `Com_create_event' numeric `GLOBAL' | `SESSION' `Com_create_function' numeric `GLOBAL' | `SESSION' `Com_create_index' numeric `GLOBAL' | `SESSION' `Com_create_procedure' numeric `GLOBAL' | `SESSION' `Com_create_server' numeric `GLOBAL' | `SESSION' `Com_create_table' numeric `GLOBAL' | `SESSION' `Com_create_trigger' numeric `GLOBAL' | `SESSION' `Com_create_udf' numeric `GLOBAL' | `SESSION' `Com_create_user' numeric `GLOBAL' | `SESSION' `Com_create_view' numeric `GLOBAL' | `SESSION' `Com_dealloc_sql' numeric `GLOBAL' | `SESSION' `Com_delete' numeric `GLOBAL' | `SESSION' `Com_delete_multi' numeric `GLOBAL' | `SESSION' `Com_do' numeric `GLOBAL' | `SESSION' `Com_drop_db' numeric `GLOBAL' | `SESSION' `Com_drop_event' numeric `GLOBAL' | `SESSION' `Com_drop_function' numeric `GLOBAL' | `SESSION' `Com_drop_index' numeric `GLOBAL' | `SESSION' `Com_drop_procedure' numeric `GLOBAL' | `SESSION' `Com_drop_server' numeric `GLOBAL' | `SESSION' `Com_drop_table' numeric `GLOBAL' | `SESSION' `Com_drop_trigger' numeric `GLOBAL' | `SESSION' `Com_drop_user' numeric `GLOBAL' | `SESSION' `Com_drop_view' numeric `GLOBAL' | `SESSION' `Com_empty_query' numeric `GLOBAL' | `SESSION' `Com_execute_sql' numeric `GLOBAL' | `SESSION' `Com_flush' numeric `GLOBAL' | `SESSION' `Com_grant' numeric `GLOBAL' | `SESSION' `Com_ha_close' numeric `GLOBAL' | `SESSION' `Com_ha_open' numeric `GLOBAL' | `SESSION' `Com_ha_read' numeric `GLOBAL' | `SESSION' `Com_help' numeric `GLOBAL' | `SESSION' `Com_insert' numeric `GLOBAL' | `SESSION' `Com_insert_select' numeric `GLOBAL' | `SESSION' `Com_install_plugin' numeric `GLOBAL' | `SESSION' `Com_kill' numeric `GLOBAL' | `SESSION' `Com_load' numeric `GLOBAL' | `SESSION' `Com_lock_tables' numeric `GLOBAL' | `SESSION' `Com_optimize' numeric `GLOBAL' | `SESSION' `Com_preload_keys' numeric `GLOBAL' | `SESSION' `Com_prepare_sql' numeric `GLOBAL' | `SESSION' `Com_purge' numeric `GLOBAL' | `SESSION' `Com_purge_before_date' numeric `GLOBAL' | `SESSION' `Com_release_savepoint' numeric `GLOBAL' | `SESSION' `Com_rename_table' numeric `GLOBAL' | `SESSION' `Com_rename_user' numeric `GLOBAL' | `SESSION' `Com_repair' numeric `GLOBAL' | `SESSION' `Com_replace' numeric `GLOBAL' | `SESSION' `Com_replace_select' numeric `GLOBAL' | `SESSION' `Com_reset' numeric `GLOBAL' | `SESSION' `Com_restore_table' numeric `GLOBAL' | `SESSION' `Com_revoke' numeric `GLOBAL' | `SESSION' `Com_revoke_all' numeric `GLOBAL' | `SESSION' `Com_rollback' numeric `GLOBAL' | `SESSION' `Com_rollback_to_savepoint' numeric `GLOBAL' | `SESSION' `Com_savepoint' numeric `GLOBAL' | `SESSION' `Com_select' numeric `GLOBAL' | `SESSION' `Com_set_option' numeric `GLOBAL' | `SESSION' `Com_show_authors' numeric `GLOBAL' | `SESSION' `Com_show_binlog_events' numeric `GLOBAL' | `SESSION' `Com_show_binlogs' numeric `GLOBAL' | `SESSION' `Com_show_charsets' numeric `GLOBAL' | `SESSION' `Com_show_collations' numeric `GLOBAL' | `SESSION' `Com_show_column_types' numeric `GLOBAL' | `SESSION' `Com_show_contributors' numeric `GLOBAL' | `SESSION' `Com_show_create_db' numeric `GLOBAL' | `SESSION' `Com_show_create_event' numeric `GLOBAL' | `SESSION' `Com_show_create_func' numeric `GLOBAL' | `SESSION' `Com_show_create_proc' numeric `GLOBAL' | `SESSION' `Com_show_create_table' numeric `GLOBAL' | `SESSION' `Com_show_create_trigger' numeric `GLOBAL' | `SESSION' `Com_show_databases' numeric `GLOBAL' | `SESSION' `Com_show_engine_logs' numeric `GLOBAL' | `SESSION' `Com_show_engine_mutex' numeric `GLOBAL' | `SESSION' `Com_show_engine_status' numeric `GLOBAL' | `SESSION' `Com_show_errors' numeric `GLOBAL' | `SESSION' `Com_show_events' numeric `GLOBAL' | `SESSION' `Com_show_fields' numeric `GLOBAL' | `SESSION' `Com_show_function_code' numeric `GLOBAL' | `SESSION' `Com_show_function_status' numeric `GLOBAL' | `SESSION' `Com_show_grants' numeric `GLOBAL' | `SESSION' `Com_show_keys' numeric `GLOBAL' | `SESSION' `Com_show_logs' numeric `GLOBAL' | `SESSION' `Com_show_master_status' numeric `GLOBAL' | `SESSION' `Com_show_ndb_status' numeric `GLOBAL' | `SESSION' `Com_show_new_master' numeric `GLOBAL' | `SESSION' `Com_show_open_tables' numeric `GLOBAL' | `SESSION' `Com_show_plugins' numeric `GLOBAL' | `SESSION' `Com_show_privileges' numeric `GLOBAL' | `SESSION' `Com_show_procedure_code' numeric `GLOBAL' | `SESSION' `Com_show_procedure_status' numeric `GLOBAL' | `SESSION' `Com_show_processlist' numeric `GLOBAL' | `SESSION' `Com_show_profile' numeric `GLOBAL' | `SESSION' `Com_show_profiles' numeric `GLOBAL' | `SESSION' `Com_show_slave_hosts' numeric `GLOBAL' | `SESSION' `Com_show_slave_status' numeric `GLOBAL' | `SESSION' `Com_show_status' numeric `GLOBAL' | `SESSION' `Com_show_storage_engines' numeric `GLOBAL' | `SESSION' `Com_show_table_status' numeric `GLOBAL' | `SESSION' `Com_show_tables' numeric `GLOBAL' | `SESSION' `Com_show_triggers' numeric `GLOBAL' | `SESSION' `Com_show_variables' numeric `GLOBAL' | `SESSION' `Com_show_warnings' numeric `GLOBAL' | `SESSION' `Com_slave_start' numeric `GLOBAL' | `SESSION' `Com_slave_stop' numeric `GLOBAL' | `SESSION' `Com_stmt_close' numeric `GLOBAL' | `SESSION' `Com_stmt_execute' numeric `GLOBAL' | `SESSION' `Com_stmt_fetch' numeric `GLOBAL' | `SESSION' `Com_stmt_prepare' numeric `GLOBAL' | `SESSION' `Com_stmt_reprepare' numeric `GLOBAL' | `SESSION' `Com_stmt_reset' numeric `GLOBAL' | `SESSION' `Com_stmt_send_long_data' numeric `GLOBAL' | `SESSION' `Com_truncate' numeric `GLOBAL' | `SESSION' `Com_uninstall_plugin' numeric `GLOBAL' | `SESSION' `Com_unlock_tables' numeric `GLOBAL' | `SESSION' `Com_update' numeric `GLOBAL' | `SESSION' `Com_update_multi' numeric `GLOBAL' | `SESSION' `Com_xa_commit' numeric `GLOBAL' | `SESSION' `Com_xa_end' numeric `GLOBAL' | `SESSION' `Com_xa_prepare' numeric `GLOBAL' | `SESSION' `Com_xa_recover' numeric `GLOBAL' | `SESSION' `Com_xa_rollback' numeric `GLOBAL' | `SESSION' `Com_xa_start' numeric `GLOBAL' | `SESSION' `Compression' numeric `SESSION' `Connections' numeric `GLOBAL' `Created_tmp_disk_tables' numeric `GLOBAL' | `SESSION' `Created_tmp_files' numeric `GLOBAL' `Created_tmp_tables' numeric `GLOBAL' | `SESSION' `Delayed_errors' numeric `GLOBAL' `Delayed_insert_threads' numeric `GLOBAL' `Delayed_writes' numeric `GLOBAL' `Flush_commands' numeric `GLOBAL' `Handler_commit' numeric `GLOBAL' | `SESSION' `Handler_delete' numeric `GLOBAL' | `SESSION' `Handler_discover' numeric `GLOBAL' | `SESSION' `Handler_prepare' numeric `GLOBAL' | `SESSION' `Handler_read_first' numeric `GLOBAL' | `SESSION' `Handler_read_key' numeric `GLOBAL' | `SESSION' `Handler_read_next' numeric `GLOBAL' | `SESSION' `Handler_read_prev' numeric `GLOBAL' | `SESSION' `Handler_read_rnd' numeric `GLOBAL' | `SESSION' `Handler_read_rnd_next' numeric `GLOBAL' | `SESSION' `Handler_rollback' numeric `GLOBAL' | `SESSION' `Handler_savepoint' numeric `GLOBAL' | `SESSION' `Handler_savepoint_rollback' numeric `GLOBAL' | `SESSION' `Handler_update' numeric `GLOBAL' | `SESSION' `Handler_write' numeric `GLOBAL' | `SESSION' `Innodb_buffer_pool_pages_data'numeric `GLOBAL' `Innodb_buffer_pool_pages_dirty'numeric `GLOBAL' `Innodb_buffer_pool_pages_flushed'numeric `GLOBAL' `Innodb_buffer_pool_pages_free'numeric `GLOBAL' `Innodb_buffer_pool_pages_latched'numeric `GLOBAL' `Innodb_buffer_pool_pages_misc'numeric `GLOBAL' `Innodb_buffer_pool_pages_total'numeric `GLOBAL' `Innodb_buffer_pool_read_ahead'numeric `GLOBAL' `Innodb_buffer_pool_read_ahead_evicted'numeric `GLOBAL' `Innodb_buffer_pool_read_ahead_rnd'numeric `GLOBAL' `Innodb_buffer_pool_read_ahead_seq'numeric `GLOBAL' `Innodb_buffer_pool_read_requests'numeric `GLOBAL' `Innodb_buffer_pool_reads' numeric `GLOBAL' `Innodb_buffer_pool_wait_free'numeric `GLOBAL' `Innodb_buffer_pool_write_requests'numeric `GLOBAL' `Innodb_data_fsyncs' numeric `GLOBAL' `Innodb_data_pending_fsyncs' numeric `GLOBAL' `Innodb_data_pending_reads' numeric `GLOBAL' `Innodb_data_pending_writes' numeric `GLOBAL' `Innodb_data_read' numeric `GLOBAL' `Innodb_data_reads' numeric `GLOBAL' `Innodb_data_writes' numeric `GLOBAL' `Innodb_data_written' numeric `GLOBAL' `Innodb_dblwr_pages_written' numeric `GLOBAL' `Innodb_dblwr_writes' numeric `GLOBAL' `Innodb_have_atomic_builtins' numeric `GLOBAL' `Innodb_log_waits' numeric `GLOBAL' `Innodb_log_write_requests' numeric `GLOBAL' `Innodb_log_writes' numeric `GLOBAL' `Innodb_os_log_fsyncs' numeric `GLOBAL' `Innodb_os_log_pending_fsyncs'numeric `GLOBAL' `Innodb_os_log_pending_writes'numeric `GLOBAL' `Innodb_os_log_written' numeric `GLOBAL' `Innodb_page_size' numeric `GLOBAL' `Innodb_pages_created' numeric `GLOBAL' `Innodb_pages_read' numeric `GLOBAL' `Innodb_pages_written' numeric `GLOBAL' `Innodb_row_lock_current_waits'numeric `GLOBAL' `Innodb_row_lock_time' numeric `GLOBAL' `Innodb_row_lock_time_avg' numeric `GLOBAL' `Innodb_row_lock_time_max' numeric `GLOBAL' `Innodb_row_lock_waits' numeric `GLOBAL' `Innodb_rows_deleted' numeric `GLOBAL' `Innodb_rows_inserted' numeric `GLOBAL' `Innodb_rows_read' numeric `GLOBAL' `Innodb_rows_updated' numeric `GLOBAL' `Key_blocks_not_flushed' numeric `GLOBAL' `Key_blocks_unused' numeric `GLOBAL' `Key_blocks_used' numeric `GLOBAL' `Key_read_requests' numeric `GLOBAL' `Key_reads' numeric `GLOBAL' `Key_write_requests' numeric `GLOBAL' `Key_writes' numeric `GLOBAL' `Last_query_cost' numeric `SESSION' `Max_used_connections' numeric `GLOBAL' `ndb_cluster_connection_pool' numeric `GLOBAL' `Ndb_cluster_node_id' numeric `GLOBAL' | `SESSION' `Ndb_config_from_host' numeric `GLOBAL' | `SESSION' `Ndb_config_from_port' numeric `GLOBAL' | `SESSION' `Ndb_conflict_fn_max' numeric `GLOBAL' `Ndb_conflict_fn_old' numeric `GLOBAL' `ndb_execute_count' numeric `GLOBAL' `ndb-nodeid' numeric `GLOBAL' `Ndb_number_of_data_nodes' numeric `GLOBAL' `ndb_pruned_scan_count' numeric `GLOBAL' `ndb_pushed_queries_defined' numeric `GLOBAL' `ndb_pushed_queries_dropped' numeric `GLOBAL' `ndb_pushed_queries_executed' numeric `GLOBAL' `ndb_pushed_reads' numeric `GLOBAL' `ndb_scan_count' numeric `GLOBAL' `Not_flushed_delayed_rows' numeric `GLOBAL' `Open_files' numeric `GLOBAL' `Open_streams' numeric `GLOBAL' `Open_table_definitions' numeric `GLOBAL' `Open_tables' numeric `GLOBAL' | `SESSION' `Opened_files' numeric `GLOBAL' `Opened_table_definitions' numeric `GLOBAL' | `SESSION' `Opened_tables' numeric `GLOBAL' | `SESSION' `Prepared_stmt_count' numeric `GLOBAL' `Qcache_free_blocks' numeric `GLOBAL' `Qcache_free_memory' numeric `GLOBAL' `Qcache_hits' numeric `GLOBAL' `Qcache_inserts' numeric `GLOBAL' `Qcache_lowmem_prunes' numeric `GLOBAL' `Qcache_not_cached' numeric `GLOBAL' `Qcache_queries_in_cache' numeric `GLOBAL' `Qcache_total_blocks' numeric `GLOBAL' `Queries' numeric `GLOBAL' | `SESSION' `Questions' numeric `GLOBAL' | `SESSION' `Rpl_status' string `GLOBAL' `Select_full_join' numeric `GLOBAL' | `SESSION' `Select_full_range_join' numeric `GLOBAL' | `SESSION' `Select_range' numeric `GLOBAL' | `SESSION' `Select_range_check' numeric `GLOBAL' | `SESSION' `Select_scan' numeric `GLOBAL' | `SESSION' `Slave_heartbeat_period' `GLOBAL' `Slave_open_temp_tables' numeric `GLOBAL' `Slave_received_heartbeats' `GLOBAL' `Slave_retried_transactions' numeric `GLOBAL' `Slave_running' boolean `GLOBAL' `Slow_launch_threads' numeric `GLOBAL' | `SESSION' `Slow_queries' numeric `GLOBAL' | `SESSION' `Sort_merge_passes' numeric `GLOBAL' | `SESSION' `Sort_range' numeric `GLOBAL' | `SESSION' `Sort_rows' numeric `GLOBAL' | `SESSION' `Sort_scan' numeric `GLOBAL' | `SESSION' `Ssl_accept_renegotiates' numeric `GLOBAL' `Ssl_accepts' numeric `GLOBAL' `Ssl_callback_cache_hits' numeric `GLOBAL' `Ssl_cipher' string `GLOBAL' | `SESSION' `Ssl_cipher_list' string `GLOBAL' | `SESSION' `Ssl_client_connects' numeric `GLOBAL' `Ssl_connect_renegotiates' numeric `GLOBAL' `Ssl_ctx_verify_depth' numeric `GLOBAL' `Ssl_ctx_verify_mode' numeric `GLOBAL' `Ssl_default_timeout' numeric `GLOBAL' | `SESSION' `Ssl_finished_accepts' numeric `GLOBAL' `Ssl_finished_connects' numeric `GLOBAL' `Ssl_session_cache_hits' numeric `GLOBAL' `Ssl_session_cache_misses' numeric `GLOBAL' `Ssl_session_cache_mode' string `GLOBAL' `Ssl_session_cache_overflows' numeric `GLOBAL' `Ssl_session_cache_size' numeric `GLOBAL' `Ssl_session_cache_timeouts' numeric `GLOBAL' `Ssl_sessions_reused' numeric `GLOBAL' | `SESSION' `Ssl_used_session_cache_entries'numeric `GLOBAL' `Ssl_verify_depth' numeric `GLOBAL' | `SESSION' `Ssl_verify_mode' numeric `GLOBAL' | `SESSION' `Ssl_version' string `GLOBAL' | `SESSION' `Table_locks_immediate' numeric `GLOBAL' `Table_locks_waited' numeric `GLOBAL' `Tc_log_max_pages_used' numeric `GLOBAL' `Tc_log_page_size' numeric `GLOBAL' `Tc_log_page_waits' numeric `GLOBAL' `Threads_cached' numeric `GLOBAL' `Threads_connected' numeric `GLOBAL' `Threads_created' numeric `GLOBAL' `Threads_running' numeric `GLOBAL' `Uptime' numeric `GLOBAL' `Uptime_since_flush_status' numeric `GLOBAL' Many status variables are reset to 0 by the `FLUSH STATUS' statement. The status variables have the following meanings. Variables with no version indicated were already present prior to MySQL 5.1. For information regarding their implementation history, see `MySQL 5.0 Reference Manual'. * `Aborted_clients' The number of connections that were aborted because the client died without closing the connection properly. See *Note communication-errors::. * `Aborted_connects' The number of failed attempts to connect to the MySQL server. See *Note communication-errors::. * `Binlog_cache_disk_use' The number of transactions that used the temporary binary log cache but that exceeded the value of `binlog_cache_size' and used a temporary file to store statements from the transaction. * `Binlog_cache_use' The number of transactions that used the temporary binary log cache. * `Bytes_received' The number of bytes received from all clients. * `Bytes_sent' The number of bytes sent to all clients. * `Com_XXX' The `Com_XXX' statement counter variables indicate the number of times each XXX statement has been executed. There is one status variable for each type of statement. For example, `Com_delete' and `Com_insert' count *Note `DELETE': delete. and *Note `INSERT': insert. statements, respectively. However, if a query result is returned from query cache, the server increments the `Qcache_hits' status variable, not `Com_select'. See *Note query-cache-status-and-maintenance::. All of the `Com_stmt_XXX' variables are increased even if a prepared statement argument is unknown or an error occurred during execution. In other words, their values correspond to the number of requests issued, not to the number of requests successfully completed. The `Com_stmt_XXX' status variables are as follows: * `Com_stmt_prepare' * `Com_stmt_execute' * `Com_stmt_fetch' * `Com_stmt_send_long_data' * `Com_stmt_reset' * `Com_stmt_close' Those variables stand for prepared statement commands. Their names refer to the `COM_XXX' command set used in the network layer. In other words, their values increase whenever prepared statement API calls such as `mysql_stmt_prepare()', `mysql_stmt_execute()', and so forth are executed. However, `Com_stmt_prepare', `Com_stmt_execute' and `Com_stmt_close' also increase for *Note `PREPARE': prepare, *Note `EXECUTE': execute, or *Note `DEALLOCATE PREPARE': deallocate-prepare, respectively. Additionally, the values of the older statement counter variables `Com_prepare_sql', `Com_execute_sql', and `Com_dealloc_sql' increase for the *Note `PREPARE': prepare, *Note `EXECUTE': execute, and *Note `DEALLOCATE PREPARE': deallocate-prepare. statements. `Com_stmt_fetch' stands for the total number of network round-trips issued when fetching from cursors. `Com_stmt_reprepare' indicated the number of times statements were automatically reprepared by the server after metadata changes to tables or views referred to by the statement. This variable was added in MySQL 5.1.25. A reprepare operation increments `Com_stmt_reprepare' is incremented, and also `Com_stmt_prepare'. * `Compression' Whether the client connection uses compression in the client/server protocol. Added in MySQL 5.1.2. * `Connections' The number of connection attempts (successful or not) to the MySQL server. * `Created_tmp_disk_tables' The number of internal on-disk temporary tables created by the server while executing statements. If an internal temporary table is created initially as an in-memory table but becomes too large, MySQL automatically converts it to an on-disk table. The maximum size for in-memory temporary tables is the minimum of the `tmp_table_size' and `max_heap_table_size' values. If `Created_tmp_disk_tables' is large, you may want to increase the `tmp_table_size' or `max_heap_table_size' values. value to lessen the likelihood that internal temporary tables in memory will be converted to on-disk tables. You can compare the number of internal on-disk temporary tables created to the total number of internal temporary tables created by comparing the values of the `Created_tmp_disk_tables' and `Created_tmp_tables' variables. See also *Note internal-temporary-tables::. * `Created_tmp_files' How many temporary files *Note `mysqld': mysqld. has created. * `Created_tmp_tables' The number of internal temporary tables created by the server while executing statements. You can compare the number of internal on-disk temporary tables created to the total number of internal temporary tables created by comparing the values of the `Created_tmp_disk_tables' and `Created_tmp_tables' variables. See also *Note internal-temporary-tables::. Each invocation of the *Note `SHOW STATUS': show-status. statement uses an internal temporary table and increments the global `Created_tmp_tables' value. * `Delayed_errors' The number of rows written with *Note `INSERT DELAYED': insert-delayed. for which some error occurred (probably `duplicate key'). * `Delayed_insert_threads' The number of *Note `INSERT DELAYED': insert-delayed. handler threads in use. * `Delayed_writes' The number of *Note `INSERT DELAYED': insert-delayed. rows written. * `Flush_commands' The number of executed *Note `FLUSH': flush. statements. * `Handler_commit' The number of internal *Note `COMMIT': commit. statements. * `Handler_delete' The number of times that rows have been deleted from tables. * `Handler_prepare' A counter for the prepare phase of two-phase commit operations. * `Handler_read_first' The number of times the first entry in an index was read. If this value is high, it suggests that the server is doing a lot of full index scans; for example, `SELECT col1 FROM foo', assuming that `col1' is indexed. * `Handler_read_key' The number of requests to read a row based on a key. If this value is high, it is a good indication that your tables are properly indexed for your queries. * `Handler_read_next' The number of requests to read the next row in key order. This value is incremented if you are querying an index column with a range constraint or if you are doing an index scan. * `Handler_read_prev' The number of requests to read the previous row in key order. This read method is mainly used to optimize `ORDER BY ... DESC'. * `Handler_read_rnd' The number of requests to read a row based on a fixed position. This value is high if you are doing a lot of queries that require sorting of the result. You probably have a lot of queries that require MySQL to scan entire tables or you have joins that do not use keys properly. * `Handler_read_rnd_next' The number of requests to read the next row in the data file. This value is high if you are doing a lot of table scans. Generally this suggests that your tables are not properly indexed or that your queries are not written to take advantage of the indexes you have. * `Handler_rollback' The number of requests for a storage engine to perform a rollback operation. * `Handler_savepoint' The number of requests for a storage engine to place a savepoint. * `Handler_savepoint_rollback' The number of requests for a storage engine to roll back to a savepoint. * `Handler_update' The number of requests to update a row in a table. * `Handler_write' The number of requests to insert a row in a table. * `Innodb_buffer_pool_pages_data' The number of pages containing data (dirty or clean). * `Innodb_buffer_pool_pages_dirty' The number of pages currently dirty. * `Innodb_buffer_pool_pages_flushed' The number of buffer pool page-flush requests. * `Innodb_buffer_pool_pages_free' The number of free pages. * `Innodb_buffer_pool_pages_latched' The number of latched pages in `InnoDB' buffer pool. These are pages currently being read or written or that cannot be flushed or removed for some other reason. Calculation of this variable is expensive, so as of MySQL 5.1.28, it is available only when the `UNIV_DEBUG' system is defined at server build time. * `Innodb_buffer_pool_pages_misc' The number of pages that are busy because they have been allocated for administrative overhead such as row locks or the adaptive hash index. This value can also be calculated as `Innodb_buffer_pool_pages_total' - `Innodb_buffer_pool_pages_free' - `Innodb_buffer_pool_pages_data'. * `Innodb_buffer_pool_pages_total' The total size of the buffer pool, in pages. * `Innodb_buffer_pool_read_ahead' (`InnoDB Plugin' only) The number of pages read into the `InnoDB' buffer pool by the read-ahead background thread. This variable was added in MySQL 5.1.41. * `Innodb_buffer_pool_read_ahead_evicted' (`InnoDB Plugin' only) The number of pages read into the `InnoDB' buffer pool by the read-ahead background thread that were subsequently evicted without having been accessed by queries. This variable was added in MySQL 5.1.41. * `Innodb_buffer_pool_read_ahead_rnd' The number of `random' read-aheads initiated by `InnoDB'. This happens when a query scans a large portion of a table but in random order. For `InnoDB Plugin', this variable was removed in MySQL 5.1.41. * `Innodb_buffer_pool_read_ahead_seq' The number of sequential read-aheads initiated by `InnoDB'. This happens when `InnoDB' does a sequential full table scan. For `InnoDB Plugin', this variable was removed in MySQL 5.1.41. * `Innodb_buffer_pool_read_requests' The number of logical read requests `InnoDB' has done. * `Innodb_buffer_pool_reads' The number of logical reads that `InnoDB' could not satisfy from the buffer pool, and had to read directly from the disk. * `Innodb_buffer_pool_wait_free' Normally, writes to the `InnoDB' buffer pool happen in the background. However, if it is necessary to read or create a page and no clean pages are available, it is also necessary to wait for pages to be flushed first. This counter counts instances of these waits. If the buffer pool size has been set properly, this value should be small. * `Innodb_buffer_pool_write_requests' The number writes done to the `InnoDB' buffer pool. * `Innodb_data_fsyncs' The number of `fsync()' operations so far. * `Innodb_data_pending_fsyncs' The current number of pending `fsync()' operations. * `Innodb_data_pending_reads' The current number of pending reads. * `Innodb_data_pending_writes' The current number of pending writes. * `Innodb_data_read' The amount of data read since the server was started. * `Innodb_data_reads' The total number of data reads. * `Innodb_data_writes' The total number of data writes. * `Innodb_data_written' The amount of data written so far, in bytes. * `Innodb_dblwr_pages_written' The number of pages that have been written for doublewrite operations. See *Note innodb-disk-io::. * `Innodb_dblwr_writes' The number of doublewrite operations that have been performed. See *Note innodb-disk-io::. * `Innodb_have_atomic_builtins' (`InnoDB Plugin' only) Indicates whether the server was built with atomic instructions. This variable was added in in MySQL 5.1.38. * `Innodb_log_waits' The number of times that the log buffer was too small and a wait was required for it to be flushed before continuing. * `Innodb_log_write_requests' The number of log write requests. * `Innodb_log_writes' The number of physical writes to the log file. * `Innodb_os_log_fsyncs' The number of `fsync()' writes done to the log file. * `Innodb_os_log_pending_fsyncs' The number of pending log file `fsync()' operations. * `Innodb_os_log_pending_writes' The number of pending log file writes. * `Innodb_os_log_written' The number of bytes written to the log file. * `Innodb_page_size' The compiled-in `InnoDB' page size (default 16KB). Many values are counted in pages; the page size enables them to be easily converted to bytes. * `Innodb_pages_created' The number of pages created. * `Innodb_pages_read' The number of pages read. * `Innodb_pages_written' The number of pages written. * `Innodb_row_lock_current_waits' The number of row locks currently being waited for. * `Innodb_row_lock_time' The total time spent in acquiring row locks, in milliseconds. * `Innodb_row_lock_time_avg' The average time to acquire a row lock, in milliseconds. * `Innodb_row_lock_time_max' The maximum time to acquire a row lock, in milliseconds. * `Innodb_row_lock_waits' The number of times a row lock had to be waited for. * `Innodb_rows_deleted' The number of rows deleted from `InnoDB' tables. * `Innodb_rows_inserted' The number of rows inserted into `InnoDB' tables. * `Innodb_rows_read' The number of rows read from `InnoDB' tables. * `Innodb_rows_updated' The number of rows updated in `InnoDB' tables. * `Key_blocks_not_flushed' The number of key blocks in the key cache that have changed but have not yet been flushed to disk. * `Key_blocks_unused' The number of unused blocks in the key cache. You can use this value to determine how much of the key cache is in use; see the discussion of `key_buffer_size' in *Note server-system-variables::. * `Key_blocks_used' The number of used blocks in the key cache. This value is a high-water mark that indicates the maximum number of blocks that have ever been in use at one time. * `Key_read_requests' The number of requests to read a key block from the cache. * `Key_reads' The number of physical reads of a key block from disk. If `Key_reads' is large, then your `key_buffer_size' value is probably too small. The cache miss rate can be calculated as `Key_reads'/`Key_read_requests'. * `Key_write_requests' The number of requests to write a key block to the cache. * `Key_writes' The number of physical writes of a key block to disk. * `Last_query_cost' The total cost of the last compiled query as computed by the query optimizer. This is useful for comparing the cost of different query plans for the same query. The default value of 0 means that no query has been compiled yet. The default value is 0. `Last_query_cost' has session scope. The `Last_query_cost' value can be computed accurately only for simple `flat' queries, not complex queries such as those with subqueries or *Note `UNION': union. For the latter, the value is set to 0. * `Max_used_connections' The maximum number of connections that have been in use simultaneously since the server started. * `Not_flushed_delayed_rows' The number of rows waiting to be written in *Note `INSERT DELAYED': insert-delayed. queues. * `Open_files' The number of files that are open. This count includes regular files opened by the server. It does not include other types of files such as sockets or pipes. Also, the count does not include files that storage engines open using their own internal functions rather than asking the server level to do so. * `Open_streams' The number of streams that are open (used mainly for logging). * `Open_table_definitions' The number of cached `.frm' files. This variable was added in MySQL 5.1.3. * `Open_tables' The number of tables that are open. * `Opened_files' The number of files that have been opened with `my_open()' (a `mysys' library function). Parts of the server that open files without using this function do not increment the count. This variable was added in MySQL 5.1.21. * `Opened_table_definitions' The number of `.frm' files that have been cached. This variable was added in MySQL 5.1.24. * `Opened_tables' The number of tables that have been opened. If `Opened_tables' is big, your `table_open_cache' value is probably too small. * `Prepared_stmt_count' The current number of prepared statements. (The maximum number of statements is given by the `max_prepared_stmt_count' system variable.) This variable was added in MySQL 5.1.14. * `Qcache_free_blocks' The number of free memory blocks in the query cache. * `Qcache_free_memory' The amount of free memory for the query cache. * `Qcache_hits' The number of query cache hits. * `Qcache_inserts' The number of queries added to the query cache. * `Qcache_lowmem_prunes' The number of queries that were deleted from the query cache because of low memory. * `Qcache_not_cached' The number of noncached queries (not cacheable, or not cached due to the `query_cache_type' setting). * `Qcache_queries_in_cache' The number of queries registered in the query cache. * `Qcache_total_blocks' The total number of blocks in the query cache. * `Queries' The number of statements executed by the server. This variable includes statements executed within stored programs, unlike the `Questions' variable. It does not count `COM_PING' or `COM_STATISTICS' commands. This variable was added in MySQL 5.1.31. * `Questions' The number of statements executed by the server. As of MySQL 5.1.31, this includes only statements sent to the server by clients and no longer includes statements executed within stored programs, unlike the `Queries' variable. This variable does not count `COM_PING', `COM_STATISTICS', `COM_STMT_PREPARE', `COM_STMT_CLOSE', or `COM_STMT_RESET' commands. * `Rpl_status' The status of fail-safe replication (not implemented). This variable is unused and is removed in MySQL 5.6. * `Select_full_join' The number of joins that perform table scans because they do not use indexes. If this value is not 0, you should carefully check the indexes of your tables. * `Select_full_range_join' The number of joins that used a range search on a reference table. * `Select_range' The number of joins that used ranges on the first table. This is normally not a critical issue even if the value is quite large. * `Select_range_check' The number of joins without keys that check for key usage after each row. If this is not 0, you should carefully check the indexes of your tables. * `Select_scan' The number of joins that did a full scan of the first table. * `Slave_open_temp_tables' The number of temporary tables that the slave SQL thread currently has open. If the value is greater than zero, it is not safe to shut down the slave; see *Note replication-features-temptables::. * `Slave_retried_transactions' The total number of times since startup that the replication slave SQL thread has retried transactions. * `Slave_running' This is `ON' if this server is a replication slave that is connected to a replication master, and both the I/O and SQL threads are running; otherwise, it is `OFF'. * `Slow_launch_threads' The number of threads that have taken more than `slow_launch_time' seconds to create. * `Slow_queries' The number of queries that have taken more than `long_query_time' seconds. See *Note slow-query-log::. * `Sort_merge_passes' The number of merge passes that the sort algorithm has had to do. If this value is large, you should consider increasing the value of the `sort_buffer_size' system variable. * `Sort_range' The number of sorts that were done using ranges. * `Sort_rows' The number of sorted rows. * `Sort_scan' The number of sorts that were done by scanning the table. * `Ssl_accept_renegotiates' The number of negotiates needed to establish the connection. * `Ssl_accepts' The number of accepted SSL connections. * `Ssl_callback_cache_hits' The number of callback cache hits. * `Ssl_cipher' The current SSL cipher (empty for non-SSL connections). * `Ssl_cipher_list' The list of possible SSL ciphers. * `Ssl_client_connects' The number of SSL connection attempts to an SSL-enabled master. * `Ssl_connect_renegotiates' The number of negotiates needed to establish the connection to an SSL-enabled master. * `Ssl_ctx_verify_depth' The SSL context verification depth (how many certificates in the chain are tested). * `Ssl_ctx_verify_mode' The SSL context verification mode. * `Ssl_default_timeout' The default SSL timeout. * `Ssl_finished_accepts' The number of successful SSL connections to the server. * `Ssl_finished_connects' The number of successful slave connections to an SSL-enabled master. * `Ssl_session_cache_hits' The number of SSL session cache hits. * `Ssl_session_cache_misses' The number of SSL session cache misses. * `Ssl_session_cache_mode' The SSL session cache mode. * `Ssl_session_cache_overflows' The number of SSL session cache overflows. * `Ssl_session_cache_size' The SSL session cache size. * `Ssl_session_cache_timeouts' The number of SSL session cache timeouts. * `Ssl_sessions_reused' How many SSL connections were reused from the cache. * `Ssl_used_session_cache_entries' How many SSL session cache entries were used. * `Ssl_verify_depth' The verification depth for replication SSL connections. * `Ssl_verify_mode' The verification mode for replication SSL connections. * `Ssl_version' The SSL protocol version of the connection. * `Table_locks_immediate' The number of times that a request for a table lock could be granted immediately. * `Table_locks_waited' The number of times that a request for a table lock could not be granted immediately and a wait was needed. If this is high and you have performance problems, you should first optimize your queries, and then either split your table or tables or use replication. * `Tc_log_max_pages_used' For the memory-mapped implementation of the log that is used by *Note `mysqld': mysqld. when it acts as the transaction coordinator for recovery of internal XA transactions, this variable indicates the largest number of pages used for the log since the server started. If the product of `Tc_log_max_pages_used' and `Tc_log_page_size' is always significantly less than the log size, the size is larger than necessary and can be reduced. (The size is set by the `--log-tc-size' option. Currently, this variable is unused: It is unneeded for binary log-based recovery, and the memory-mapped recovery log method is not used unless the number of storage engines capable of two-phase commit is greater than one. (`InnoDB' is the only applicable engine.) * `Tc_log_page_size' The page size used for the memory-mapped implementation of the XA recovery log. The default value is determined using `getpagesize()'. Currently, this variable is unused for the same reasons as described for `Tc_log_max_pages_used'. * `Tc_log_page_waits' For the memory-mapped implementation of the recovery log, this variable increments each time the server was not able to commit a transaction and had to wait for a free page in the log. If this value is large, you might want to increase the log size (with the `--log-tc-size' option). For binary log-based recovery, this variable increments each time the binary log cannot be closed because there are two-phase commits in progress. (The close operation waits until all such transactions are finished.) * `Threads_cached' The number of threads in the thread cache. * `Threads_connected' The number of currently open connections. * `Threads_created' The number of threads created to handle connections. If `Threads_created' is big, you may want to increase the `thread_cache_size' value. The cache miss rate can be calculated as `Threads_created'/`Connections'. * `Threads_running' The number of threads that are not sleeping. * `Uptime' The number of seconds that the server has been up. * `Uptime_since_flush_status' The number of seconds since the most recent `FLUSH STATUS' statement. This variable was added in 5.1.24.  File: manual.info, Node: server-sql-mode, Next: server-plugins, Prev: server-status-variables, Up: mysqld-server 6.1.6 Server SQL Modes ---------------------- The MySQL server can operate in different SQL modes, and can apply these modes differently for different clients. This capability enables each application to tailor the server's operating mode to its own requirements. For answers to some questions that are often asked about server SQL modes in MySQL, see *Note faqs-sql-modes::. Modes define what SQL syntax MySQL should support and what kind of data validation checks it should perform. This makes it easier to use MySQL in different environments and to use MySQL together with other database servers. You can set the default SQL mode by starting *Note `mysqld': mysqld. with the `--sql-mode="MODES"' option, or by using `sql-mode="MODES"' in `my.cnf' (Unix operating systems) or `my.ini' (Windows). MODES is a list of different modes separated by comma (``,'') characters. The default value is empty (no modes set). The MODES value also can be empty (`--sql-mode=""' on the command line, or `sql-mode=""' in `my.cnf' on Unix systems or in `my.ini' on Windows) if you want to clear it explicitly. You can change the SQL mode at runtime by using a `SET [GLOBAL|SESSION] sql_mode='MODES'' statement to set the `sql_mode' system value. Setting the `GLOBAL' variable requires the `SUPER' privilege and affects the operation of all clients that connect from that time on. Setting the `SESSION' variable affects only the current client. Any client can change its own session `sql_mode' value at any time. *Important*: SQL mode and user-defined partitioning Changing the server SQL mode after creating and inserting data into partitioned tables can cause major changes in the behavior of such tables, and could lead to loss or corruption of data. It is strongly recommended that you never change the SQL mode once you have created tables employing user-defined partitioning. When replicating partitioned tables, differing SQL modes on master and slave can also lead to problems. For best results, you should always use the same server SQL mode on the master and on the slave. See *Note partitioning-limitations::, for more information. You can retrieve the current global or session `sql_mode' value with the following statements: SELECT @@GLOBAL.sql_mode; SELECT @@SESSION.sql_mode; The most important `sql_mode' values are probably these: * `ANSI' This mode changes syntax and behavior to conform more closely to standard SQL. * `STRICT_TRANS_TABLES' If a value could not be inserted as given into a transactional table, abort the statement. For a nontransactional table, abort the statement if the value occurs in a single-row statement or the first row of a multiple-row statement. More detail is given later in this section. * `TRADITIONAL' Make MySQL behave like a `traditional' SQL database system. A simple description of this mode is `give an error instead of a warning' when inserting an incorrect value into a column. *Note*: The *Note `INSERT': insert./*Note `UPDATE': update. aborts as soon as the error is noticed. This may not be what you want if you are using a nontransactional storage engine, because data changes made prior to the error may not be rolled back, resulting in a `partially done' update. When this manual refers to `strict mode,' it means a mode where at least one of `STRICT_TRANS_TABLES' or `STRICT_ALL_TABLES' is enabled. The following list describes all supported modes: * `ALLOW_INVALID_DATES' Do not perform full checking of dates. Check only that the month is in the range from 1 to 12 and the day is in the range from 1 to 31. This is very convenient for Web applications where you obtain year, month, and day in three different fields and you want to store exactly what the user inserted (without date validation). This mode applies to *Note `DATE': datetime. and *Note `DATETIME': datetime. columns. It does not apply *Note `TIMESTAMP': datetime. columns, which always require a valid date. The server requires that month and day values be legal, and not merely in the range 1 to 12 and 1 to 31, respectively. With strict mode disabled, invalid dates such as `'2004-04-31'' are converted to `'0000-00-00'' and a warning is generated. With strict mode enabled, invalid dates generate an error. To permit such dates, enable `ALLOW_INVALID_DATES'. * `ANSI_QUOTES' Treat ``"'' as an identifier quote character (like the ```'' quote character) and not as a string quote character. You can still use ```'' to quote identifiers with this mode enabled. With `ANSI_QUOTES' enabled, you cannot use double quotation marks to quote literal strings, because it is interpreted as an identifier. * `ERROR_FOR_DIVISION_BY_ZERO' Produce an error in strict mode (otherwise a warning) when a division by zero (or `MOD(X,0)') occurs during an *Note `INSERT': insert. or *Note `UPDATE': update. If this mode is not enabled, MySQL instead returns `NULL' for divisions by zero. For *Note `INSERT IGNORE': insert. or `UPDATE IGNORE', MySQL generates a warning for divisions by zero, but the result of the operation is `NULL'. * `HIGH_NOT_PRECEDENCE' The precedence of the `NOT' operator is such that expressions such as `NOT a BETWEEN b AND c' are parsed as `NOT (a BETWEEN b AND c)'. In some older versions of MySQL, the expression was parsed as `(NOT a) BETWEEN b AND c'. The old higher-precedence behavior can be obtained by enabling the `HIGH_NOT_PRECEDENCE' SQL mode. mysql> SET sql_mode = ''; mysql> SELECT NOT 1 BETWEEN -5 AND 5; -> 0 mysql> SET sql_mode = 'HIGH_NOT_PRECEDENCE'; mysql> SELECT NOT 1 BETWEEN -5 AND 5; -> 1 * `IGNORE_SPACE' Permit spaces between a function name and the ``('' character. This causes built-in function names to be treated as reserved words. As a result, identifiers that are the same as function names must be quoted as described in *Note identifiers::. For example, because there is a `COUNT()' function, the use of `count' as a table name in the following statement causes an error: mysql> CREATE TABLE count (i INT); ERROR 1064 (42000): You have an error in your SQL syntax The table name should be quoted: mysql> CREATE TABLE `count` (i INT); Query OK, 0 rows affected (0.00 sec) The `IGNORE_SPACE' SQL mode applies to built-in functions, not to user-defined functions or stored functions. It is always permissible to have spaces after a UDF or stored function name, regardless of whether `IGNORE_SPACE' is enabled. For further discussion of `IGNORE_SPACE', see *Note function-resolution::. * `NO_AUTO_CREATE_USER' Prevent the *Note `GRANT': grant. statement from automatically creating new users if it would otherwise do so, unless a nonempty password also is specified. * `NO_AUTO_VALUE_ON_ZERO' `NO_AUTO_VALUE_ON_ZERO' affects handling of `AUTO_INCREMENT' columns. Normally, you generate the next sequence number for the column by inserting either `NULL' or `0' into it. `NO_AUTO_VALUE_ON_ZERO' suppresses this behavior for `0' so that only `NULL' generates the next sequence number. This mode can be useful if `0' has been stored in a table's `AUTO_INCREMENT' column. (Storing `0' is not a recommended practice, by the way.) For example, if you dump the table with *Note `mysqldump': mysqldump. and then reload it, MySQL normally generates new sequence numbers when it encounters the `0' values, resulting in a table with contents different from the one that was dumped. Enabling `NO_AUTO_VALUE_ON_ZERO' before reloading the dump file solves this problem. *Note `mysqldump': mysqldump. now automatically includes in its output a statement that enables `NO_AUTO_VALUE_ON_ZERO', to avoid this problem. * `NO_BACKSLASH_ESCAPES' Disable the use of the backslash character (``\'') as an escape character within strings. With this mode enabled, backslash becomes an ordinary character like any other. * `NO_DIR_IN_CREATE' When creating a table, ignore all `INDEX DIRECTORY' and `DATA DIRECTORY' directives. This option is useful on slave replication servers. * `NO_ENGINE_SUBSTITUTION' Control automatic substitution of the default storage engine when a statement such as *Note `CREATE TABLE': create-table. or *Note `ALTER TABLE': alter-table. specifies a storage engine that is disabled or not compiled in. Up through MySQL 5.1.11, with `NO_ENGINE_SUBSTITUTION' disabled, the default engine is used and a warning occurs if the desired engine is known but disabled or not compiled in. If the desired engine is invalid (not a known engine name), an error occurs and the table is not created or altered. With `NO_ENGINE_SUBSTITUTION' enabled, an error occurs and the table is not created or altered if the desired engine is unavailable for any reason (whether disabled or invalid). As of MySQL 5.1.12, storage engines can be pluggable at runtime, so the distinction between disabled and invalid no longer applies. All unavailable engines are treated the same way: With `NO_ENGINE_SUBSTITUTION' disabled, for *Note `CREATE TABLE': create-table. the default engine is used and a warning occurs if the desired engine is unavailable. For *Note `ALTER TABLE': alter-table, a warning occurs and the table is not altered. With `NO_ENGINE_SUBSTITUTION' enabled, an error occurs and the table is not created or altered if the desired engine is unavailable. * `NO_FIELD_OPTIONS' Do not print MySQL-specific column options in the output of *Note `SHOW CREATE TABLE': show-create-table. This mode is used by *Note `mysqldump': mysqldump. in portability mode. * `NO_KEY_OPTIONS' Do not print MySQL-specific index options in the output of *Note `SHOW CREATE TABLE': show-create-table. This mode is used by *Note `mysqldump': mysqldump. in portability mode. * `NO_TABLE_OPTIONS' Do not print MySQL-specific table options (such as `ENGINE') in the output of *Note `SHOW CREATE TABLE': show-create-table. This mode is used by *Note `mysqldump': mysqldump. in portability mode. * `NO_UNSIGNED_SUBTRACTION' By default, subtraction between integer operands produces an `UNSIGNED' result if any operand is`UNSIGNED'. When `NO_UNSIGNED_SUBTRACTION' is enabled, the subtraction result is signed, _even if any operand is unsigned_. For example, compare the type of column `c2' in table `t1' with that of column `c2' in table `t2': mysql> SET sql_mode=''; mysql> CREATE TABLE test (c1 BIGINT UNSIGNED NOT NULL); mysql> CREATE TABLE t1 SELECT c1 - 1 AS c2 FROM test; mysql> DESCRIBE t1; +-------+---------------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +-------+---------------------+------+-----+---------+-------+ | c2 | bigint(21) unsigned | | | 0 | | +-------+---------------------+------+-----+---------+-------+ mysql> SET sql_mode='NO_UNSIGNED_SUBTRACTION'; mysql> CREATE TABLE t2 SELECT c1 - 1 AS c2 FROM test; mysql> DESCRIBE t2; +-------+------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +-------+------------+------+-----+---------+-------+ | c2 | bigint(21) | | | 0 | | +-------+------------+------+-----+---------+-------+ Note that this means that `BIGINT UNSIGNED' is not 100% usable in all contexts. See *Note cast-functions::. mysql> SET sql_mode = ''; mysql> SELECT CAST(0 AS UNSIGNED) - 1; +-------------------------+ | CAST(0 AS UNSIGNED) - 1 | +-------------------------+ | 18446744073709551615 | +-------------------------+ mysql> SET sql_mode = 'NO_UNSIGNED_SUBTRACTION'; mysql> SELECT CAST(0 AS UNSIGNED) - 1; +-------------------------+ | CAST(0 AS UNSIGNED) - 1 | +-------------------------+ | -1 | +-------------------------+ * `NO_ZERO_DATE' In strict mode, do not permit `'0000-00-00'' as a valid date. You can still insert zero dates with the `IGNORE' option. When not in strict mode, the date is accepted but a warning is generated. * `NO_ZERO_IN_DATE' In strict mode, do not accept dates where the year part is nonzero but the month or day part is 0 (for example, `'0000-00-00'' is legal but `'2010-00-01'' and `'2010-01-00'' are not). If used with the `IGNORE' option, MySQL inserts a `'0000-00-00'' date for any such date. When not in strict mode, the date is accepted but a warning is generated. * `ONLY_FULL_GROUP_BY' Do not permit queries for which the select list refers to nonaggregated columns that are not named in the `GROUP BY' clause. The following query is invalid with this mode enabled because `address' is not named in the `GROUP BY' clause: SELECT name, address, MAX(age) FROM t GROUP BY name; As of MySQL 5.1.11, this mode also restricts references to nonaggregated columns in the `HAVING' clause that are not named in the `GROUP BY' clause. * `PAD_CHAR_TO_FULL_LENGTH' By default, trailing spaces are trimmed from *Note `CHAR': char. column values on retrieval. If `PAD_CHAR_TO_FULL_LENGTH' is enabled, trimming does not occur and retrieved *Note `CHAR': char. values are padded to their full length. This mode does not apply to *Note `VARCHAR': char. columns, for which trailing spaces are retained on retrieval. This mode was added in MySQL 5.1.20. mysql> CREATE TABLE t1 (c1 CHAR(10)); Query OK, 0 rows affected (0.37 sec) mysql> INSERT INTO t1 (c1) VALUES('xy'); Query OK, 1 row affected (0.01 sec) mysql> SET sql_mode = ''; Query OK, 0 rows affected (0.00 sec) mysql> SELECT c1, CHAR_LENGTH(c1) FROM t1; +------+-----------------+ | c1 | CHAR_LENGTH(c1) | +------+-----------------+ | xy | 2 | +------+-----------------+ 1 row in set (0.00 sec) mysql> SET sql_mode = 'PAD_CHAR_TO_FULL_LENGTH'; Query OK, 0 rows affected (0.00 sec) mysql> SELECT c1, CHAR_LENGTH(c1) FROM t1; +------------+-----------------+ | c1 | CHAR_LENGTH(c1) | +------------+-----------------+ | xy | 10 | +------------+-----------------+ 1 row in set (0.00 sec) * `PIPES_AS_CONCAT' Treat `||' as a string concatenation operator (same as `CONCAT()') rather than as a synonym for `OR'. * `REAL_AS_FLOAT' Treat *Note `REAL': numeric-types. as a synonym for *Note `FLOAT': numeric-types. By default, MySQL treats *Note `REAL': numeric-types. as a synonym for *Note `DOUBLE': numeric-types. * `STRICT_ALL_TABLES' Enable strict mode for all storage engines. Invalid data values are rejected. Additional detail follows. * `STRICT_TRANS_TABLES' Enable strict mode for transactional storage engines, and when possible for nontransactional storage engines. Additional details follow. Strict mode controls how MySQL handles input values that are invalid or missing. A value can be invalid for several reasons. For example, it might have the wrong data type for the column, or it might be out of range. A value is missing when a new row to be inserted does not contain a value for a non-`NULL' column that has no explicit `DEFAULT' clause in its definition. (For a `NULL' column, `NULL' is inserted if the value is missing.) For transactional tables, an error occurs for invalid or missing values in a statement when either of the `STRICT_ALL_TABLES' or `STRICT_TRANS_TABLES' modes are enabled. The statement is aborted and rolled back. For nontransactional tables, the behavior is the same for either mode, if the bad value occurs in the first row to be inserted or updated. The statement is aborted and the table remains unchanged. If the statement inserts or modifies multiple rows and the bad value occurs in the second or later row, the result depends on which strict option is enabled: * For `STRICT_ALL_TABLES', MySQL returns an error and ignores the rest of the rows. However, in this case, the earlier rows still have been inserted or updated. This means that you might get a partial update, which might not be what you want. To avoid this, it is best to use single-row statements because these can be aborted without changing the table. * For `STRICT_TRANS_TABLES', MySQL converts an invalid value to the closest valid value for the column and insert the adjusted value. If a value is missing, MySQL inserts the implicit default value for the column data type. In either case, MySQL generates a warning rather than an error and continues processing the statement. Implicit defaults are described in *Note data-type-defaults::. Strict mode disallows invalid date values such as `'2004-04-31''. It does not disallow dates with zero month or day parts such as `'2004-04-00'' or `zero' dates. To disallow these as well, enable the `NO_ZERO_IN_DATE' and `NO_ZERO_DATE' SQL modes in addition to strict mode. If you are not using strict mode (that is, neither `STRICT_TRANS_TABLES' nor `STRICT_ALL_TABLES' is enabled), MySQL inserts adjusted values for invalid or missing values and produces warnings. In strict mode, you can produce this behavior by using *Note `INSERT IGNORE': insert. or `UPDATE IGNORE'. See *Note show-warnings::. Strict mode does not affect whether foreign key constraints are checked. `foreign_key_checks' can be used for that. (See *Note server-system-variables::.) The following special modes are provided as shorthand for combinations of mode values from the preceding list. The descriptions include all mode values that are available in the most recent version of MySQL. For older versions, a combination mode does not include individual mode values that are not available except in newer versions. * `ANSI' Equivalent to `REAL_AS_FLOAT', `PIPES_AS_CONCAT', `ANSI_QUOTES', `IGNORE_SPACE'. As of MySQL 5.1.18, `ANSI' mode also causes the server to return an error for queries where a set function S with an outer reference `S(OUTER_REF)' cannot be aggregated in the outer query against which the outer reference has been resolved. This is such a query: SELECT * FROM t1 WHERE t1.a IN (SELECT MAX(t1.b) FROM t2 WHERE ...); Here, `MAX(t1.b)' cannot aggregated in the outer query because it appears in the `WHERE' clause of that query. Standard SQL requires an error in this situation. If `ANSI' mode is not enabled, the server treats `S(OUTER_REF)' in such queries the same way that it would interpret `S(CONST)', as was always done prior to 5.1.18. See *Note ansi-mode::. * `DB2' Equivalent to `PIPES_AS_CONCAT', `ANSI_QUOTES', `IGNORE_SPACE', `NO_KEY_OPTIONS', `NO_TABLE_OPTIONS', `NO_FIELD_OPTIONS'. * `MAXDB' Equivalent to `PIPES_AS_CONCAT', `ANSI_QUOTES', `IGNORE_SPACE', `NO_KEY_OPTIONS', `NO_TABLE_OPTIONS', `NO_FIELD_OPTIONS', `NO_AUTO_CREATE_USER'. * `MSSQL' Equivalent to `PIPES_AS_CONCAT', `ANSI_QUOTES', `IGNORE_SPACE', `NO_KEY_OPTIONS', `NO_TABLE_OPTIONS', `NO_FIELD_OPTIONS'. * `MYSQL323' Equivalent to `NO_FIELD_OPTIONS', `HIGH_NOT_PRECEDENCE'. * `MYSQL40' Equivalent to `NO_FIELD_OPTIONS', `HIGH_NOT_PRECEDENCE'. * `ORACLE' Equivalent to `PIPES_AS_CONCAT', `ANSI_QUOTES', `IGNORE_SPACE', `NO_KEY_OPTIONS', `NO_TABLE_OPTIONS', `NO_FIELD_OPTIONS', `NO_AUTO_CREATE_USER'. * `POSTGRESQL' Equivalent to `PIPES_AS_CONCAT', `ANSI_QUOTES', `IGNORE_SPACE', `NO_KEY_OPTIONS', `NO_TABLE_OPTIONS', `NO_FIELD_OPTIONS'. * `TRADITIONAL' Equivalent to `STRICT_TRANS_TABLES', `STRICT_ALL_TABLES', `NO_ZERO_IN_DATE', `NO_ZERO_DATE', `ERROR_FOR_DIVISION_BY_ZERO', `NO_AUTO_CREATE_USER'.  File: manual.info, Node: server-plugins, Next: server-side-help-support, Prev: server-sql-mode, Up: mysqld-server 6.1.7 Server Plugins -------------------- * Menu: * server-plugin-loading:: Installing and Uninstalling Plugins * obtaining-plugin-information:: Obtaining Server Plugin Information MySQL 5.1 and up supports a plugin API that enables creation of server components. Plugins can be loaded at server startup, or loaded and unloaded at runtime without restarting the server. The components supported by this interface include, but are not limited to, storage engines, full-text parser plugins, partitioning support, and server extensions.  File: manual.info, Node: server-plugin-loading, Next: obtaining-plugin-information, Prev: server-plugins, Up: server-plugins 6.1.7.1 Installing and Uninstalling Plugins ........................................... Server plugins must be loaded in to the server before they can be used. MySQL enables you to load a plugin at server startup or at runtime. It is also possible to control the activation of loaded plugins at startup, and to unload them at runtime. * Installing plugins * Controlling plugin activation * Uninstalling plugins * Installing Plugins * Server plugins must be known to the server before they can be used. A plugin can be made known several ways, as described here. In the following descriptions, PLUGIN_NAME stands for a plugin name such as `innodb' or `csv'. *Built-in plugins:* A plugin that is built in to the server is known by the server automatically. Normally, the server enables the plugin at startup, although this can be changed with the `--PLUGIN_NAME' option. *Plugins registered in the `mysql.plugin' table:* The `mysql.plugin' table serves as a registry of plugins. The server normally enables each plugin listed in the table at startup, although whether a given plugin is enabled can be changed with the `--PLUGIN_NAME' option. If the server is started with the `--skip-grant-tables' option, it does not consult this table and does not load the plugins listed there. *Plugins named with the `--plugin-load' option:* A plugin that is located in a plugin library file can be loaded at server startup with the `--plugin-load' option. Normally, the server enables the plugin at startup, although this can be changed with the `--PLUGIN_NAME' option. The option value is a semicolon-separated list of `NAME=PLUGIN_LIBRARY' pairs. Each NAME is the name of the plugin, and PLUGIN_LIBRARY is the name of the shared library that contains the plugin code. If a plugin library is named without any preceding plugin name, the server loads all plugins in the library. Each library file must be located in the directory named by the `plugin_dir' system variable. This option does not register any plugin in the `mysql.plugin' table. For subsequent restarts, the server loads the plugin again only if `--plugin-load' is given again. That is, this option effects a one-time installation that persists only for one server invocation. `--plugin-load' enables plugins to be loaded even when `--skip-grant-tables' is given (which causes the server to ignore the `mysql.plugin' table). `--plugin-load' also enables plugins to be loaded at startup under configurations when plugins cannot be loaded at runtime. *Plugins installed with the *Note `INSTALL PLUGIN': install-plugin. statement:* A plugin that is located in a plugin library file can be loaded at runtime with the `INSTALL PLUGIN' statement. The statement also registers the plugin in the `mysql.plugin' table to cause the server to load it on subsequent restarts. For this reason, `INSTALL PLUGIN' requires the `INSERT' privilege for the `mysql.plugin' table. If a plugin is named both using a `--plugin-load' option and in the `mysql.plugin' table, the server starts but writes these messages to the error log: 100310 19:15:44 [ERROR] Function 'PLUGIN_NAME' already exists 100310 19:15:44 [Warning] Couldn't load plugin named 'PLUGIN_NAME' with soname 'PLUGIN_OBJECT_FILE'. Example: The `--plugin-load' option installs a plugin at server startup. To install a plugin named `myplugin' in a plugin library file named `somepluglib.so', use these lines in a `my.cnf' file: [mysqld] plugin-load=myplugin=somepluglib.so In this case, the plugin is not registered in `mysql.plugin'. Restarting the server without the `--plugin-load' option causes the plugin not to be loaded at startup. Alternatively, the *Note `INSTALL PLUGIN': install-plugin. statement causes the server to load the plugin code from the library file at runtime: mysql> INSTALL PLUGIN myplugin SONAME 'somepluglib.so'; *Note `INSTALL PLUGIN': install-plugin. also causes `permanent' plugin registration: The server lists the plugin in the `mysql.plugin' table to ensure that it is loaded on subsequent server restarts. Many plugins can be loaded either at server startup or at runtime. However, if a plugin is designed such that it must be loaded and initialized during server startup, use `--plugin-load' rather than *Note `INSTALL PLUGIN': install-plugin. While a plugin is loaded, information about it is available at runtime from several sources, such as the *Note `INFORMATION_SCHEMA.PLUGINS': plugins-table. table and the *Note `SHOW PLUGINS': show-plugins. statement. For more information, see *Note obtaining-plugin-information::. * Controlling Plugin Activation * If the server knows about a plugin when it starts (for example, because the plugin is named using a `--plugin-load' option or registered in the `mysql.plugin' table), the server loads and enables the plugin by default. It is possible to control activation for such a plugin using a `--PLUGIN_NAME[=VALUE]' startup option named after the plugin. In the following descriptions, PLUGIN_NAME stands for a plugin name such as `innodb' or `csv'. As with other options, dashes and underscores are interchangeable in option names. For example, `--my_plugin=ON' and `--my-plugin=ON' are equivalent. As of MySQL 5.1.36, these options control plugin loading: * `--PLUGIN_NAME=OFF' Tells the server to disable the plugin. * `--PLUGIN_NAME[=ON]' Tells the server to enable the plugin. (Specifying the option as `--PLUGIN_NAME' without a value has the same effect.) If the plugin fails to initialize, the server runs with the plugin disabled. * `--PLUGIN_NAME=FORCE' Tells the server to enable the plugin, but if plugin initialization fails, the server does not start. In other words, this option forces the server to run with the plugin enabled or not at all. The values `OFF', `ON', and `FORCE' are not case sensitive. Suppose that `CSV', `BLACKHOLE', and `ARCHIVE' are built-in pluggable storage engines and that you want the server to load them at startup, subject to these conditions: The server is permitted to run if `CSV' initialization fails, but must require that `BLACKHOLE' initialization succeeds, and `ARCHIVE' should be disabled. To accomplish that, use these lines in an option file: [mysqld] csv=ON blackhole=FORCE archive=OFF The `--enable-PLUGIN_NAME' option format is supported as a synonym for `--PLUGIN_NAME=ON'. The `--disable-PLUGIN_NAME' and `--skip-PLUGIN_NAME' option formats are supported as synonyms for `--PLUGIN_NAME=OFF'. Before MySQL 5.1.36, plugin options are boolean options (see *Note option-modifiers::). That is, any of these options enable the plugin: --PLUGIN_NAME --PLUGIN_NAME=1 --enable-PLUGIN_NAME And these options disable the plugin: --PLUGIN_NAME=0 --disable-PLUGIN_NAME --skip-PLUGIN_NAME If you upgrade to MySQL 5.1.36 or later from an older version and previously used options of the form `--PLUGIN_NAME=0' or `--PLUGIN_NAME=1', the equivalent options are now `--PLUGIN_NAME=OFF' and `--PLUGIN_NAME=ON', respectively. You also have the choice of requiring plugins to start successfully by using `--PLUGIN_NAME=FORCE'. If a plugin is disabled, either explicitly with `OFF' or implicitly because it was enabled with `ON' but failed to initialize, aspects of server operation that require the plugin will change. For example, if the plugin implements a storage engine, existing tables for the storage engine become inaccessible, and attempts to create new tables for the storage engine result in tables that use the default storage engine unless the `NO_ENGINE_SUBSTITUTION' SQL mode has been enabled to cause an error to occur instead. Disabling a plugin may require adjustment to other options. For example, if *Note `InnoDB': innodb-storage-engine. is disabled, other `innodb_XXX' options likely will need to be omitted from the startup command. In addition, if the server is configured to use *Note `InnoDB': innodb-storage-engine. as the default storage engine, it will not start unless you specify another available storage engine with `--default-storage-engine'. * Uninstalling Plugins * A plugin known to the server can be uninstalled to disable it at runtime with the *Note `UNINSTALL PLUGIN': uninstall-plugin. statement. The statement unloads the plugin and removes it from the `mysql.plugin' table if it is registered there. For this reason, *Note `UNINSTALL PLUGIN': uninstall-plugin. statement requires the `DELETE' privilege for the `mysql.plugin' table. With the plugin no longer registered in the table, the server will not load the plugin automatically for subsequent restarts. *Note `UNINSTALL PLUGIN': uninstall-plugin. can unload plugins regardless of whether they were loaded with *Note `INSTALL PLUGIN': install-plugin. or `--plugin-load'. *Note `UNINSTALL PLUGIN': uninstall-plugin. cannot unload plugins that are built in to the server. These can be identified as those that have a library name of `NULL' in the output from *Note `INFORMATION_SCHEMA.PLUGINS': plugins-table. or *Note `SHOW PLUGINS': show-plugins.  File: manual.info, Node: obtaining-plugin-information, Prev: server-plugin-loading, Up: server-plugins 6.1.7.2 Obtaining Server Plugin Information ........................................... There are several ways to determine which plugins are installed in the server: * The *Note `INFORMATION_SCHEMA.PLUGINS': plugins-table. table contains a row for each loaded plugin. Any that have a `PLUGIN_LIBRARY' value of `NULL' are built in and cannot be unloaded. mysql> SELECT * FROM information_schema.PLUGINS\G *************************** 1. row *************************** PLUGIN_NAME: binlog PLUGIN_VERSION: 1.0 PLUGIN_STATUS: ACTIVE PLUGIN_TYPE: STORAGE ENGINE PLUGIN_TYPE_VERSION: 50158.0 PLUGIN_LIBRARY: NULL PLUGIN_LIBRARY_VERSION: NULL PLUGIN_AUTHOR: MySQL AB PLUGIN_DESCRIPTION: This is a pseudo storage engine to represent the binlog in a transaction PLUGIN_LICENSE: GPL ... *************************** 10. row *************************** PLUGIN_NAME: InnoDB PLUGIN_VERSION: 1.0 PLUGIN_STATUS: ACTIVE PLUGIN_TYPE: STORAGE ENGINE PLUGIN_TYPE_VERSION: 50158.0 PLUGIN_LIBRARY: ha_innodb_plugin.so PLUGIN_LIBRARY_VERSION: 1.0 PLUGIN_AUTHOR: Innobase Oy PLUGIN_DESCRIPTION: Supports transactions, row-level locking, and foreign keys PLUGIN_LICENSE: GPL ... * The *Note `SHOW PLUGINS': show-plugins. statement displays a row for each loaded plugin. Any that have a `Library' value of `NULL' are built in and cannot be unloaded. mysql> SHOW PLUGINS\G *************************** 1. row *************************** Name: binlog Status: ACTIVE Type: STORAGE ENGINE Library: NULL License: GPL ... *************************** 10. row *************************** Name: InnoDB Status: ACTIVE Type: STORAGE ENGINE Library: ha_innodb_plugin.so License: GPL ... * The `mysql.plugin' table shows which plugins have been registered with *Note `INSTALL PLUGIN': install-plugin. The table contains only plugin names and library file names, so it does not provide as much information as the *Note `PLUGINS': plugins-table. table or the *Note `SHOW PLUGINS': show-plugins. statement.  File: manual.info, Node: server-side-help-support, Next: server-signal-response, Prev: server-plugins, Up: mysqld-server 6.1.8 Server-Side Help ---------------------- MySQL Server supports a *Note `HELP': help. statement that returns online information from the MySQL Reference manual (see *Note help::). The proper operation of this statement requires that the help tables in the `mysql' database be initialized with help topic information, which is done by processing the contents of the `fill_help_tables.sql' script. If you install MySQL using a binary or source distribution on Unix, help table setup occurs when you run *Note `mysql_install_db': mysql-install-db. For an RPM distribution on Linux or binary distribution on Windows, help table setup occurs as part of the MySQL installation process. If you upgrade MySQL using a binary distribution, the help tables are not upgraded automatically, but you can upgrade them manually. Locate the `fill_help_tables.sql' file in the `share' or `share/mysql' directory. Change location into that directory and process the file with the *Note `mysql': mysql. client as follows: shell> mysql -u root mysql < fill_help_tables.sql You can also obtain the latest `fill_help_tables.sql' at any time to upgrade your help tables. Download the proper file for your version of MySQL from `http://dev.mysql.com/doc/index-other.html'. After downloading and uncompressing the file, process it with *Note `mysql': mysql. as described previously. If you are working with Bazaar and a MySQL development source tree, you will need to download the `fill_help_tables.sql' file because the tree contains only a `stub' version.  File: manual.info, Node: server-signal-response, Next: server-shutdown, Prev: server-side-help-support, Up: mysqld-server 6.1.9 Server Response to Signals -------------------------------- On Unix, signals can be sent to processes. *Note `mysqld': mysqld. responds to signals sent to it as follows: * `SIGTERM' causes the server to shut down. * `SIGHUP' causes the server to reload the grant tables and flush the logs (like *Note `FLUSH PRIVILEGES': flush. and *Note `FLUSH LOGS': flush.). It also writes a status report to the error log that has this format: Status information: Current dir: /var/mysql/data/ Running threads: 0 Stack size: 196608 Current locks: Key caches: default Buffer_size: 8388600 Block_size: 1024 Division_limit: 100 Age_limit: 300 blocks used: 0 not flushed: 0 w_requests: 0 writes: 0 r_requests: 0 reads: 0 handler status: read_key: 0 read_next: 0 read_rnd 0 read_first: 1 write: 0 delete 0 update: 0 Table status: Opened tables: 5 Open tables: 0 Open files: 7 Open streams: 0 Alarm status: Active alarms: 1 Max used alarms: 2 Next alarm time: 67 On some Mac OS X 10.3 versions, *Note `mysqld': mysqld. ignores `SIGHUP' and `SIGQUIT'.  File: manual.info, Node: server-shutdown, Prev: server-signal-response, Up: mysqld-server 6.1.10 The Shutdown Process --------------------------- The server shutdown process takes place as follows: 1. The shutdown process is initiated. This can occur initiated several ways. For example, a user with the `SHUTDOWN' privilege can execute a *Note `mysqladmin shutdown': mysqladmin. command. *Note `mysqladmin': mysqladmin. can be used on any platform supported by MySQL. Other operating system-specific shutdown initiation methods are possible as well: The server shuts down on Unix when it receives a `SIGTERM' signal. A server running as a service on Windows shuts down when the services manager tells it to. 2. The server creates a shutdown thread if necessary. Depending on how shutdown was initiated, the server might create a thread to handle the shutdown process. If shutdown was requested by a client, a shutdown thread is created. If shutdown is the result of receiving a `SIGTERM' signal, the signal thread might handle shutdown itself, or it might create a separate thread to do so. If the server tries to create a shutdown thread and cannot (for example, if memory is exhausted), it issues a diagnostic message that appears in the error log: Error: Can't create thread to kill server 3. The server stops accepting new connections. To prevent new activity from being initiated during shutdown, the server stops accepting new client connections by closing the handlers for the network interfaces to which it normally listens for connections: the TCP/IP port, the Unix socket file, the Windows named pipe, and shared memory on Windows. 4. The server terminates current activity. For each thread associated with a client connection, the server breaks the connection to the client and marks the thread as killed. Threads die when they notice that they are so marked. Threads for idle connections die quickly. Threads that currently are processing statements check their state periodically and take longer to die. For additional information about thread termination, see *Note kill::, in particular for the instructions about killed *Note `REPAIR TABLE': repair-table. or *Note `OPTIMIZE TABLE': optimize-table. operations on `MyISAM' tables. For threads that have an open transaction, the transaction is rolled back. Note that if a thread is updating a nontransactional table, an operation such as a multiple-row *Note `UPDATE': update. or *Note `INSERT': insert. may leave the table partially updated because the operation can terminate before completion. If the server is a master replication server, it treats threads associated with currently connected slaves like other client threads. That is, each one is marked as killed and exits when it next checks its state. If the server is a slave replication server, it stops the the I/O and SQL threads, if they are active, before marking client threads as killed. The SQL thread is permitted to finish its current statement (to avoid causing replication problems), and then stops. If the SQL thread was in the middle of a transaction at this point, the transaction is rolled back. If the slave is updating a non-transactional table when it is forcibly killed, the slave's data may become inconsistent with the master. 5. The server shuts down or closes storage engines. At this stage, the server flushes the table cache and closes all open tables. Each storage engine performs any actions necessary for tables that it manages. For example, `MyISAM' flushes any pending index writes for a table. `InnoDB' flushes its buffer pool to disk (unless `innodb_fast_shutdown' is 2), writes the current LSN to the tablespace, and terminates its own internal threads. 6. The server exits.  File: manual.info, Node: server-logs, Next: security, Prev: mysqld-server, Up: server-administration 6.2 MySQL Server Logs ===================== * Menu: * log-destinations:: Selecting General Query and Slow Query Log Output Destinations * error-log:: The Error Log * query-log:: The General Query Log * binary-log:: The Binary Log * slow-query-log:: The Slow Query Log * log-file-maintenance:: Server Log Maintenance MySQL Server has several different logs that can help you find out what activity is taking place. Log Type Information Written to Log Error log Problems encountered starting, running, or stopping *Note `mysqld': mysqld. General query log Established client connections and statements received from clients Binary log All statements that change data (also used for replication) Relay log Data changes received from a replication master server Slow query log All queries that took more than `long_query_time' seconds to execute or did not use indexes By default, all log files are created in the data directory. You can force the server to close and reopen the log files (or in some cases switch to a new log file) by flushing the logs. Log flushing occurs when you issue a *Note `FLUSH LOGS': flush. statement or execute a *Note `mysqladmin flush-logs': mysqladmin, *Note `mysqladmin refresh': mysqladmin, *Note `mysqldump --flush-logs': mysqldump, or *Note `mysqldump --master-data': mysqldump. command. See *Note flush::, *Note mysqladmin::, and *Note mysqldump::. In addition, the binary log is flushed when its size reaches the value of the `max_binlog_size' system variable. The relay log is used only on slave replication servers, to hold data changes from the master server that must also be made on the slave. For discussion of relay log contents and configuration, see *Note slave-logs-relaylog::. As of MySQL 5.1.6, the server can write general query and slow query entries to log tables, log files, or both. For details, see *Note log-destinations::. As of MySQL 5.1.12, additional runtime control of the general query and slow query logs is available: You can enable or disable logging, or change the name of the log file. See *Note query-log::, and *Note slow-query-log::. For information about log maintenance operations such as expiration of old log files, see *Note log-file-maintenance::. For information about keeping logs secure, see *Note password-security-admin::.  File: manual.info, Node: log-destinations, Next: error-log, Prev: server-logs, Up: server-logs 6.2.1 Selecting General Query and Slow Query Log Output Destinations -------------------------------------------------------------------- As of MySQL 5.1.6, MySQL Server provides flexible control over the destination of output to the general query log and the slow query log. Possible destinations for log entries are log files or the the `general_log' and `slow_log' tables in the `mysql' database. If logging is enabled, either or both destinations can be selected. (Before MySQL 5.1.6, the server uses only log files as the destination for general query log and slow query log entries, if those logs are enabled.) *Note*: For new installations of MySQL 5.1.6 or higher, the log tables are created during the installation procedure along with the other system tables. If you upgrade MySQL from a release older than 5.1.6 to MySQL 5.1.6 or higher, you must upgrade the system tables after upgrading to make sure that the log tables exist. See *Note mysql-upgrade::. Currently, logging to tables incurs significantly more server overhead than logging to files. If you enable the general log or slow query log and require highest performance, you should use file logging, not table logging. *Log control at server startup.* The `--log-output' option specifies the destination for log output, if logging is enabled. This option does not in itself enable the logs. Its syntax is `--log-output[=VALUE,...]': * If `--log-output' is given with a value, the value should be a comma-separated list of one or more of the words `TABLE' (log to tables), `FILE' (log to files), or `NONE' (do not log to tables or files). `NONE', if present, takes precedence over any other specifiers. * If `--log-output' is omitted or given without a value, the default is `FILE'. (For MySQL 5.1.6 through 5.1.20, the default logging destination is `TABLE'.) The `general_log' system variable, if given, enables logging to the general query log for the selected log destinations. If specified at server startup, `general_log' takes an optional argument of 1 or 0 to enable or disable the log. To specify a file name other than the default for file logging, set the `general_log_file' variable. Similarly, the `slow_query_log' variable, if given, enables logging to the slow query log for the selected destinations and setting `slow_query_log_file' specifies a file name for file logging. If either log is enabled, the server opens the corresponding log file and writes startup messages to it. However, further logging of queries to the file does not occur unless the `FILE' log destination is selected. Prior to MySQL 5.1.29, the `--log' and `--log-slow-queries' options enable the general query log and slow query log. Either option may be given with a file name argument to specify a log file name to override the default. Examples: * To write general query log entries to the log table and the log file, use `--log-output=TABLE,FILE' to select both log destinations and the `--general_log' option to enable the general query log. * To write general and slow query log entries only to the log tables, use `--log-output=TABLE' to select tables as the log destination and the `--general_log' and `--slow_query_log' options to enable both logs. * To write slow query log entries only to the log file, use `--log-output=FILE' to select files as the log destination and the `--slow_query_log' option to enable the slow query log. (In this case, because the default log destination is `FILE', you could omit the `--log-output' option.) *Log control at runtime.* Several system variables are associated with log tables and files and enable runtime control over logging: * The global `log_output' system variable indicates the current logging destination. It can be modified at runtime to change the destination. * The global `general_log' and `slow_query_log' variables indicate whether the general query log and slow query log are enabled (`ON') or disabled (`OFF'). You can set these variables at runtime to control whether the logs are enabled. * The global `general_log_file' and `slow_query_log_file' variables indicate the names of the general query log and slow query log files. As of MySQL 5.1.29, you can set these variables at server startup or at runtime to change the names of the log files. Before MySQL 5.1.29, you can set these variables only at runtime, but the `--log' and `--log-slow-queries' options can be given with a file name argument at startup to change the log file names from their default values. * The session `sql_log_off' variable can be set to `ON' or `OFF' to disable or enable general query logging for the current connection. The use of tables for log output offers the following benefits: * Log entries have a standard format. To display the current structure of the log tables, use these statements: SHOW CREATE TABLE mysql.general_log; SHOW CREATE TABLE mysql.slow_log; * Log contents are accessible through SQL statements. This enables the use of queries that select only those log entries that satisfy specific criteria. For example, to select log contents associated with a particular client (which can be useful for identifying problematic queries from that client), it is easier to do this using a log table than a log file. * Logs are accessible remotely through any client that can connect to the server and issue queries (if the client has the appropriate log table privileges). It is not necessary to log in to the server host and directly access the file system. The log table implementation has the following characteristics: * In general, the primary purpose of log tables is to provide an interface for users to observe the runtime execution of the server, not to interfere with its runtime execution. * *Note `CREATE TABLE': create-table, *Note `ALTER TABLE': alter-table, and *Note `DROP TABLE': drop-table. are valid operations on a log table. For *Note `ALTER TABLE': alter-table. and *Note `DROP TABLE': drop-table, the log table cannot be in use and must be disabled, as described later. * By default, the log tables use the `CSV' storage engine that writes data in comma-separated values format. For users who have access to the `.CSV' files that contain log table data, the files are easy to import into other programs such as spreadsheets that can process CSV input. Beginning with MySQL 5.1.12, the log tables can be altered to use the `MyISAM' storage engine. You cannot use *Note `ALTER TABLE': alter-table. to alter a log table that is in use. The log must be disabled first. No engines other than `CSV' or `MyISAM' are legal for the log tables. * To disable logging so that you can alter (or drop) a log table, you can use the following strategy. The example uses the general query log; the procedure for the slow query log is similar but uses the `slow_log' table and `slow_query_log' system variable. SET @old_log_state = @@global.general_log; SET GLOBAL general_log = 'OFF'; ALTER TABLE mysql.general_log ENGINE = MyISAM; SET GLOBAL general_log = @old_log_state; * *Note `TRUNCATE TABLE': truncate-table. is a valid operation on a log table. It can be used to expire log entries. * As of MySQL 5.1.13, *Note `RENAME TABLE': rename-table. is a valid operation on a log table. You can atomically rename a log table (to perform log rotation, for example) using the following strategy: USE mysql; CREATE TABLE IF NOT EXISTS general_log2 LIKE general_log; RENAME TABLE general_log TO general_log_backup, general_log2 TO general_log; * *Note `LOCK TABLES': lock-tables. cannot be used on a log table. * *Note `INSERT': insert, *Note `DELETE': delete, and *Note `UPDATE': update. cannot be used on a log table. These operations are permitted only internally to the server itself. * *Note `FLUSH TABLES WITH READ LOCK': flush. and the state of the global `read_only' system variable have no effect on log tables. The server can always write to the log tables. * Entries written to the log tables are not written to the binary log and thus are not replicated to slave servers. * To flush the log tables or log files, use *Note `FLUSH TABLES': flush. or *Note `FLUSH LOGS': flush, respectively. (From MySQL 5.1.12 to 5.1.20, *Note `FLUSH TABLES': flush. ignores log tables and *Note `FLUSH LOGS': flush. flushes both the log tables and files.) * Partitioning of log tables is not permitted beginning with MySQL 5.1.20, and not recommended before that.  File: manual.info, Node: error-log, Next: query-log, Prev: log-destinations, Up: server-logs 6.2.2 The Error Log ------------------- The error log contains information indicating when *Note `mysqld': mysqld. was started and stopped and also any critical errors that occur while the server is running. If *Note `mysqld': mysqld. notices a table that needs to be automatically checked or repaired, it writes a message to the error log. On some operating systems, the error log contains a stack trace if *Note `mysqld': mysqld. dies. The trace can be used to determine where *Note `mysqld': mysqld. died. See MySQL Internals: Porting (http://forge.mysql.com/wiki/MySQL_Internals_Porting). You can specify where *Note `mysqld': mysqld. writes the error log with the `--log-error[=FILE_NAME]' option. If the option is given with no FILE_NAME value, *Note `mysqld': mysqld. uses the name `HOST_NAME.err' by default. The server creates the file in the data directory unless an absolute path name is given to specify a different directory. If you do not specify `--log-error', or (on Windows) if you use the `--console' option, errors are written to `stderr', the standard error output. Usually this is your terminal. On Windows, error output is always written to the `.err' file if `--console' is not given. In addition, on Windows, events and error messages are written to the Windows Event Log within the Application log. Entries marked as `Warning' and `Note' are written to the Event Log, but informational messages (such as information statements from individual storage engines) are not copied to the Event Log. The log entries have a source of `MySQL'. You cannot disable writing information to the Windows Event Log. If you flush the logs using *Note `FLUSH LOGS': flush. or *Note `mysqladmin flush-logs': mysqladmin. and *Note `mysqld': mysqld. is writing the error log to a file (for example, if it was started with the `--log-error' option), the effect is version dependent: * As of MySQL 5.1.51, the server closes and reopens the log file. To rename the file, you can do so manually before flushing. Then flushing the logs reopens a new file with the original file name. For example, you can rename the file and create a new one using the following commands: shell> mv HOST_NAME.err HOST_NAME.err-old shell> mysqladmin flush-logs shell> mv HOST_NAME.err-old BACKUP-DIRECTORY On Windows, use `rename' rather than `mv'. * Prior to MySQL 5.1.51, the server renames the current log file with the suffix `-old', then creates a new empty log file. Be aware that a second log-flushing operation thus causes the original error log file to be lost unless you save it under a different name. On Windows, you cannot rename the error log while the server has it open before MySQL 5.1.51. To avoid a restart, flush the logs first to cause the server to rename the original file and create a new one, then save the renamed file. That also works on Unix, or you can use the commands shown earlier. No error log renaming occurs when the logs are flushed in any case if the server is not writing to a named file. The `--log-warnings' option or `log_warnings' system variable can be used to control warning logging to the error log. The default value is enabled (1). Warning logging can be disabled using a value of 0. If the value is greater than 1, aborted connections are written to the error log. See *Note communication-errors::. If you use *Note `mysqld_safe': mysqld-safe. to start *Note `mysqld': mysqld, *Note `mysqld_safe': mysqld-safe. arranges for *Note `mysqld': mysqld. to write error messages to a log file or (as of MySQL 5.1.20) to `syslog': * Before 5.1.20, *Note `mysqld_safe': mysqld-safe. behavior is to log to a file, using the default error log file if the `--log-error' option is not given to *Note `mysqld_safe': mysqld-safe. Otherwise, *Note `mysqld_safe': mysqld-safe. uses the file name specified using `--log-error=FILE_NAME'. * From 5.1.20 on, *Note `mysqld_safe': mysqld-safe. has two additional error-logging options, `--syslog' and `--skip-syslog'. In 5.1.21 and up, the default with no logging options is `--skip-syslog', which is compatible with the default behavior of writing an error log file for releases prior to 5.1.20. To explicitly specify use of an error log file, specify `--log-error=FILE_NAME' to *Note `mysqld_safe': mysqld-safe, and *Note `mysqld_safe': mysqld-safe. will arrange for *Note `mysqld': mysqld. to write messages to a log file. To use `syslog' instead, specify the `--syslog' option. *In 5.1.20 _only_, the following conditions apply*: 1) The default is to use `syslog', which is not compatible with releases prior to 5.1.20. 2) Logging to `syslog' may fail to operate correctly in some cases; if so, use `--skip-syslog' or `--log-error'. For logging to `syslog', messages from *Note `mysqld_safe': mysqld-safe. and *Note `mysqld': mysqld. are written with a tag of `mysqld_safe' and `mysqld', respectively. As of MySQL 5.1.21, to specify a suffix for the tag, use `--syslog-tag=TAG', which modifies the tags to be `mysqld_safe-TAG' and `mysqld-TAG'. If you specify `--log-error' in an option file in a section that *Note `mysqld': mysqld. reads, *Note `mysqld_safe': mysqld-safe. also will find and use the option. If *Note `mysqld_safe': mysqld-safe. is used to start *Note `mysqld': mysqld. and *Note `mysqld': mysqld. dies unexpectedly, *Note `mysqld_safe': mysqld-safe. notices that it needs to restart *Note `mysqld': mysqld. and writes a `restarted mysqld' message to the error log.  File: manual.info, Node: query-log, Next: binary-log, Prev: error-log, Up: server-logs 6.2.3 The General Query Log --------------------------- The general query log is a general record of what *Note `mysqld': mysqld. is doing. The server writes information to this log when clients connect or disconnect, and it logs each SQL statement received from clients. The general query log can be very useful when you suspect an error in a client and want to know exactly what the client sent to *Note `mysqld': mysqld. *Note `mysqld': mysqld. writes statements to the query log in the order that it receives them, which might differ from the order in which they are executed. This logging order contrasts to the binary log, for which statements are written after they are executed but before any locks are released. (Also, the query log contains all statements, whereas the binary log does not contain statements that only select data.) Control the general query log at server startup as follows: * Before 5.1.6, the general query log destination is always a file. To enable the log, start *Note `mysqld': mysqld. with the `--log[=FILE_NAME]' or `-l [FILE_NAME]' option. * As of MySQL 5.1.6, the destination can be a file or a table, or both. Start *Note `mysqld': mysqld. with the `--log[=FILE_NAME]' or `-l [FILE_NAME]' option to enable the general query log, and optionally use `--log-output' to specify the log destination (as described in *Note log-destinations::). * As of MySQL 5.1.12, as an alternative to `--log' or `-l', use `--general_log[={0|1}]' to specify the initial general query log state. In this case, the default general query log file name is used. With no argument or an argument of 1, `--general_log' enables the log. With an argument of 0, this option disables the log. * As of MySQL 5.1.29, use `--general_log[={0|1}]' to enable or disable the general query log, and optionally `--general_log_file=FILE_NAME' to specify a log file name. The `--log' and `-l' options are deprecated. If you specify no name for the general query log file, the default name is `HOST_NAME.log'. The server creates the file in the data directory unless an absolute path name is given to specify a different directory. To control the general query log at runtime, use the global `general_log' and `general_log_file' system variables. Set `general_log' to 0 (or `OFF') to disable the log or to 1 (or `ON') to enable it. Set `general_log_file' to specify the name of the log file. If a log file already is open, it is closed and the new file is opened. When the general query log is enabled, the server writes output to any destinations specified by the `--log-output' option or `log_output' system variable. If you enable the log, the server opens the log file and writes startup messages to it. However, further logging of queries to the file does not occur unless the `FILE' log destination is selected. If the destination is `NONE', no queries are written even if the general log is enabled. Setting the log file name has no effect on logging if the log destination value does not contain `FILE'. Server restarts and log flushing do not cause a new general query log file to be generated (although flushing closes and reopens it). On Unix, you can rename the file and create a new one by using the following commands: shell> mv HOST_NAME.log HOST_NAME-old.log shell> mysqladmin flush-logs shell> mv HOST_NAME-old.log BACKUP-DIRECTORY On Windows, you cannot rename the general query log file while the server has it open before MySQL 5.1.3. You must stop the server, rename the file, and then restart the server to create a new log file. As of MySQL 5.1.12, you can rename the general query log file at runtime by disabling the log: SET GLOBAL general_log = 'OFF'; With the log disabled, rename the log file externally; for example, from the command line. Then enable the log again: SET GLOBAL general_log = 'ON'; This method works on any platform and does not require a server restart. The session `sql_log_off' variable can be set to `ON' or `OFF' to disable or enable general query logging for the current connection. The general query log should be protected because logged statements might contain passwords. See *Note password-security-admin::.  File: manual.info, Node: binary-log, Next: slow-query-log, Prev: query-log, Up: server-logs 6.2.4 The Binary Log -------------------- * Menu: * binary-log-formats:: Binary Logging Formats * binary-log-setting:: Setting The Binary Log Format * binary-log-mixed:: Mixed Binary Logging Format * binary-log-mysql-database:: Logging Format for Changes to `mysql' Database Tables The binary log contains `events' that describe database changes such as table creation operations or changes to table data. It also contains events for statements that potentially could have made changes (for example, a *Note `DELETE': delete. which matched no rows), unless row-based logging is used. The binary log also contains information about how long each statement took that updated data. The binary log has two important purposes: * For replication, the binary log is used on master replication servers as a record of the statements to be sent to slave servers. The master server sends the events contained in its binary log to its slaves, which execute those events to make the same data changes that were made on the master. See *Note replication-implementation::. * Certain data recovery operations require use of the binary log. After a backup has been restored, the events in the binary log that were recorded after the backup was made are re-executed. These events bring databases up to date from the point of the backup. See *Note point-in-time-recovery::. Running a server with binary logging enabled makes performance slightly slower. However, the benefits of the binary log in enabling you to set up replication and for restore operations generally outweigh this minor performance decrement. For information about server options and variables affecting the operation of binary logging, see *Note replication-options-binary-log::. The binary log is not used for statements such as *Note `SELECT': select. or *Note `SHOW': show. that do not modify data. If you want to log all statements (for example, to identify a problem query), use the general query log. See *Note query-log::. The binary log should be protected because logged statements might contain passwords. See *Note password-security-admin::. The format of the events recorded in the binary log is dependent on the binary logging format. Three format types are supported, row-based logging, statement-based logging and mixed-base logging. The binary logging format used depends on the MySQL version. For more information on logging formats, see *Note binary-log-formats::. For information about the format of the binary log itself, see `http://forge.mysql.com/wiki/MySQL_Internals_Binary_Log'. To enable the binary log, start the server with the `--log-bin[=BASE_NAME]' option. If no BASE_NAME value is given, the default name is the value of the `pid-file' option (which by default is the name of host machine) followed by `-bin'. If the basename is given, the server writes the file in the data directory unless the basename is given with a leading absolute path name to specify a different directory. It is recommended that you specify a basename; see *Note bugs::, for the reason. *Note*: From MySQL 5.1.18 through 5.1.22, `mysql' was used when no BASE_NAME was specified. Also in these versions, a path given as part of the `--log-bin' options was treated as absolute rather than relative. The previous behaviors were restored in MySQL 5.1.23. (See Bug#28603 and Bug#28597.) If you supply an extension in the log name (for example, `--log-bin=BASE_NAME.EXTENSION'), the extension is silently removed and ignored. *Note `mysqld': mysqld. appends a numeric extension to the binary log basename to generate binary log file names. The number increases each time the server creates a new log file, thus creating an ordered series of files. The server creates a new file in the series each time it starts or flushes the logs. The server also creates a new binary log file automatically after the current log's size reaches `max_binlog_size'. A binary log file may become larger than `max_binlog_size' if you are using large transactions because a transaction is written to the file in one piece, never split between files. To keep track of which binary log files have been used, *Note `mysqld': mysqld. also creates a binary log index file that contains the names of all used binary log files. By default, this has the same basename as the binary log file, with the extension `'.index''. You can change the name of the binary log index file with the `--log-bin-index[=FILE_NAME]' option. You should not manually edit this file while *Note `mysqld': mysqld. is running; doing so would confuse *Note `mysqld': mysqld. The term `binary log file' generally denotes an individual numbered file containing database events. The term `binary log' collectively denotes the set of numbered binary log files plus the index file. The server evaluates the `--binlog-do-db' and `--binlog-ignore-db' options in the same way as it does the `--replicate-do-db' and `--replicate-ignore-db' options. For information about how this is done, see *Note replication-rules-db-options::. A replication slave server by default does not write to its own binary log any data modifications that are received from the replication master. To log these modifications, start the slave with the `--log-slave-updates' option in addition to the `--log-bin' option (see *Note replication-options-slave::). This is done when a slave is also to act as a master to other slaves in chained replication. You can delete all binary log files with the *Note `RESET MASTER': reset-master. statement, or a subset of them with *Note `PURGE BINARY LOGS': purge-binary-logs. See *Note reset::, and *Note purge-binary-logs::. If you are using replication, you should not delete old binary log files on the master until you are sure that no slave still needs to use them. For example, if your slaves never run more than three days behind, once a day you can execute *Note `mysqladmin flush-logs': mysqladmin. on the master and then remove any logs that are more than three days old. You can remove the files manually, but it is preferable to use *Note `PURGE BINARY LOGS': purge-binary-logs, which also safely updates the binary log index file for you (and which can take a date argument). See *Note purge-binary-logs::. A client that has the `SUPER' privilege can disable binary logging of its own statements by using a `SET sql_log_bin=0' statement. See *Note server-system-variables::. You can display the contents of binary log files with the *Note `mysqlbinlog': mysqlbinlog. utility. This can be useful when you want to reprocess statements in the log for a recovery operation. For example, you can update a MySQL server from the binary log as follows: shell> mysqlbinlog LOG_FILE | mysql -h SERVER_NAME *Note `mysqlbinlog': mysqlbinlog. also can be used to display replication slave relay log file contents because they are written using the same format as binary log files. For more information on the *Note `mysqlbinlog': mysqlbinlog. utility and how to use it, see *Note mysqlbinlog::. For more information about the binary log and recovery operations, see *Note point-in-time-recovery::. Binary logging is done immediately after a statement completes but before any locks are released or any commit is done. This ensures that the log is logged in execution order. Updates to nontransactional tables are stored in the binary log immediately after execution. In MySQL 5.1.22 and earlier versions of MySQL 5.1, an *Note `UPDATE': update. statement using a stored function that modified a nontransactional table was not logged if it failed, and an *Note `INSERT ... ON DUPLICATE KEY UPDATE': insert-on-duplicate. statement that encountered a duplicate key constraint--but did not actually change any data--was not logged. Beginning with MySQL 5.1.23, both of these statements are written to the binary log. (Bug#23333) Within an uncommitted transaction, all updates (*Note `UPDATE': update, *Note `DELETE': delete, or *Note `INSERT': insert.) that change transactional tables such as `InnoDB' tables are cached until a *Note `COMMIT': commit. statement is received by the server. At that point, *Note `mysqld': mysqld. writes the entire transaction to the binary log before the *Note `COMMIT': commit. is executed. Modifications to nontransactional tables cannot be rolled back. If a transaction that is rolled back includes modifications to nontransactional tables, the entire transaction is logged with a *Note `ROLLBACK': commit. statement at the end to ensure that the modifications to those tables are replicated. When a thread that handles the transaction starts, it allocates a buffer of `binlog_cache_size' to buffer statements. If a statement is bigger than this, the thread opens a temporary file to store the transaction. The temporary file is deleted when the thread ends. The `Binlog_cache_use' status variable shows the number of transactions that used this buffer (and possibly a temporary file) for storing statements. The `Binlog_cache_disk_use' status variable shows how many of those transactions actually had to use a temporary file. These two variables can be used for tuning `binlog_cache_size' to a large enough value that avoids the use of temporary files. The `max_binlog_cache_size' system variable (default 4GB, which is also the maximum) can be used to restrict the total size used to cache a multiple-statement transaction. If a transaction is larger than this many bytes, it fails and rolls back. The minimum value is 4096. If you are using the binary log and row based logging, concurrent inserts are converted to normal inserts for `CREATE ... SELECT' or *Note `INSERT ... SELECT': insert-select. statement. This is done to ensure that you can re-create an exact copy of your tables by applying the log during a backup operation. If you are using statement-based logging, the original statement is written to the log. The binary log format has some known limitations that can affect recovery from backups. See *Note replication-features::. Binary logging for stored programs is done as described in *Note stored-programs-logging::. Note that the binary log format differs in MySQL 5.1 from previous versions of MySQL, due to enhancements in replication. See *Note replication-compatibility::. Writes to the binary log file and binary log index file are handled in the same way as writes to `MyISAM' tables. See *Note full-disk::. By default, the binary log is not synchronized to disk at each write. So if the operating system or machine (not only the MySQL server) crashes, there is a chance that the last statements of the binary log are lost. To prevent this, you can make the binary log be synchronized to disk after every N writes to the binary log, with the `sync_binlog' system variable. See *Note server-system-variables::. 1 is the safest value for `sync_binlog', but also the slowest. Even with `sync_binlog' set to 1, there is still the chance of an inconsistency between the table content and binary log content in case of a crash. For example, if you are using `InnoDB' tables and the MySQL server processes a *Note `COMMIT': commit. statement, it writes the whole transaction to the binary log and then commits this transaction into `InnoDB'. If the server crashes between those two operations, the transaction is rolled back by `InnoDB' at restart but still exists in the binary log. To resolve this, you should set `--innodb_support_xa' to 1. Although this option is related to the support of XA transactions in InnoDB, it also ensures that the binary log and InnoDB data files are synchronized. For this option to provide a greater degree of safety, the MySQL server should also be configured to synchronize the binary log and the `InnoDB' logs to disk at every transaction. The `InnoDB' logs are synchronized by default, and `sync_binlog=1' can be used to synchronize the binary log. The effect of this option is that at restart after a crash, after doing a rollback of transactions, the MySQL server cuts rolled back `InnoDB' transactions from the binary log. This ensures that the binary log reflects the exact data of `InnoDB' tables, and so, that the slave remains in synchrony with the master (not receiving a statement which has been rolled back). If the MySQL server discovers at crash recovery that the binary log is shorter than it should have been, it lacks at least one successfully committed `InnoDB' transaction. This should not happen if `sync_binlog=1' and the disk/file system do an actual sync when they are requested to (some do not), so the server prints an error message `The binary log FILE_NAME is shorter than its expected size'. In this case, this binary log is not correct and replication should be restarted from a fresh snapshot of the master's data. For MySQL 5.1.20 and later (and MySQL 5.0.46 and later for backward compatibility), the session values of the following system variables are written to the binary log and honored by the replication slave when parsing the binary log: * `sql_mode' (except that the `NO_DIR_IN_CREATE' mode is not replicated; see *Note replication-features-variables::) * `foreign_key_checks' * `unique_checks' * `character_set_client' * `collation_connection' * `collation_database' * `collation_server' * `sql_auto_is_null'  File: manual.info, Node: binary-log-formats, Next: binary-log-setting, Prev: binary-log, Up: binary-log 6.2.4.1 Binary Logging Formats .............................. A number of different logging formats are used to record information in the binary log. The exact format employed depends on the version of MySQL being used. There are three logging formats: * Replication capabilities in MySQL originally were based on propagation of SQL statements from master to slave. This is called _statement-based logging_. You can cause this format to be used by starting the server with `--binlog-format=STATEMENT'. * In _row-based logging_, the master writes events to the binary log that indicate how individual table rows are affected. You can cause the server to use row-based logging by starting it with `--binlog-format=ROW'. * A third option is also available: _mixed logging_. With mixed logging, statement-based logging is used by default, but the logging mode switches automatically to row-based in certain cases as described below. You can cause MySQL to use mixed logging explicitly by starting *Note `mysqld': mysqld. with the option `--binlog-format=MIXED'. Support for row-based logging was added in MySQL 5.1.5. Mixed logging is available beginning with MySQL 5.1.8. In MySQL 5.1.12, it become the default logging mode; in 5.1.29, the default was changed back to `STATEMENT' for compatibility with MySQL 5.0. Starting with MySQL 5.1.20, the logging format can also be set or limited by the storage engine being used. This helps to eliminate issues when replicating certain statements between a master and slave that are using different storage engines. With statement-based replication, there may be issues with replicating nondeterministic statements. In deciding whether or not a given statement is safe for statement-based replication, MySQL determines whether it can guarantee that the statement can be replicated using statement-based logging. If MySQL cannot make this guarantee, it marks the statement as potentially unreliable and issues the warning, `Statement may not be safe to log in statement format'. Prior to MySQL 5.1.36, this warning read, `Statement is not safe to log in statement format'. (Bug#42415) You can avoid these issues by using MySQL's row-based replication instead.  File: manual.info, Node: binary-log-setting, Next: binary-log-mixed, Prev: binary-log-formats, Up: binary-log 6.2.4.2 Setting The Binary Log Format ..................................... You can select the binary logging format explicitly by starting the MySQL server with `--binlog-format=TYPE'. The supported values for TYPE are: * `STATEMENT' causes logging to be statement-based. * `ROW' causes logging to be row-based. * `MIXED' causes logging to use mixed format. The default binary logging format depends on the version of MySQL you are using: * For MySQL 5.1.11 and earlier, and for MySQL 5.1.29 and later, statement-based logging is used by default. * For MySQL 5.1.12 through MySQL 5.1.28, mixed logging is used by default. Exception For all MySQL Cluster releases using version 6.1 or later of the *Note `NDBCLUSTER': mysql-cluster. storage engine (even those releases based on MySQL 5.1.29 and later), the default binary log format is `MIXED'. See *Note mysql-cluster-replication::. The logging format also can be switched at runtime. To specify the format globally for all clients, set the global value of the `binlog_format' system variable: mysql> SET GLOBAL binlog_format = 'STATEMENT'; mysql> SET GLOBAL binlog_format = 'ROW'; mysql> SET GLOBAL binlog_format = 'MIXED'; An individual client can control the logging format for its own statements by setting the session value of `binlog_format': mysql> SET SESSION binlog_format = 'STATEMENT'; mysql> SET SESSION binlog_format = 'ROW'; mysql> SET SESSION binlog_format = 'MIXED'; To change the global `binlog_format' value, you must have the `SUPER' privilege. This is also true for the session value as of MySQL 5.1.29. In addition to switching the logging format manually, a slave server may switch the format _automatically_. This happens when the server is running in either `STATEMENT' or `MIXED' format and encounters an event in the binary log that is written in `ROW' logging format. In that case, the slave switches to row-based replication temporarily for that event, and switches back to the previous format afterward. There are several reasons why a client might want to set binary logging on a per-session basis: * A session that makes many small changes to the database might want to use row-based logging. * A session that performs updates that match many rows in the `WHERE' clause might want to use statement-based logging because it will be more efficient to log a few statements than many rows. * Some statements require a lot of execution time on the master, but result in just a few rows being modified. It might therefore be beneficial to replicate them using row-based logging. There are exceptions when you cannot switch the replication format at runtime: * From within a stored function or a trigger * If the *Note `NDBCLUSTER': mysql-cluster. storage engine is enabled * If the session is currently in row-based replication mode and has open temporary tables Trying to switch the format in any of these cases results in an error. Switching the replication format at runtime is not recommended when any temporary tables exist, because temporary tables are logged only when using statement-based replication, whereas with row-based replication they are not logged. With mixed replication, temporary tables are usually logged; exceptions happen with user-defined functions (UDFs) and with the `UUID()' function. With the binary log format set to `ROW', many changes are written to the binary log using the row-based format. Some changes, however, still use the statement-based format. Examples include all DDL (data definition language) statements such as *Note `CREATE TABLE': create-table, *Note `ALTER TABLE': alter-table, or *Note `DROP TABLE': drop-table. The `--binlog-row-event-max-size' option is available for servers that are capable of row-based replication. Rows are stored into the binary log in chunks having a size in bytes not exceeding the value of this option. The value must be a multiple of 256. The default value is 1024. *Warning*: When using _statement-based logging_ for replication, it is possible for the data on the master and slave to become different if a statement is designed in such a way that the data modification is _nondeterministic_; that is, it is left to the will of the query optimizer. In general, this is not a good practice even outside of replication. For a detailed explanation of this issue, see *Note bugs::.  File: manual.info, Node: binary-log-mixed, Next: binary-log-mysql-database, Prev: binary-log-setting, Up: binary-log 6.2.4.3 Mixed Binary Logging Format ................................... When running in `MIXED' logging format, automatic switching from statement-based to row-based logging takes place under the following conditions: * When a DML statement updates an *Note `NDBCLUSTER': mysql-cluster. table. * When a function contains `UUID()'. * Prior to MySQL 5.1.40, when two or more tables with `AUTO_INCREMENT' columns are updated. As of 5.1.40, when one or more tables with `AUTO_INCREMENT' columns are updated and a trigger or stored function is invoked. Unlike other unsafe statements, this does not generate a warning if `binlog_format = STATEMENT'. For more information, see *Note replication-features-auto-increment::. * When any *Note `INSERT DELAYED': insert-delayed. is executed. * When the body of a view requires row-based replication, the statement creating the view also uses it. For example, this occurs when the statement creating a view uses the `UUID()' function. * When a call to a UDF is involved. * If a statement is logged by row and the session that executed the statement has any temporary tables, logging by row is used for all subsequent statements (except for those accessing temporary tables) until all temporary tables in use by that session are dropped. This is true whether or not any temporary tables are actually logged. Temporary tables cannot be logged using row-based format; thus, once row-based logging is used, all subsequent statements using that table are unsafe. The server approximates this condition by treating all statements executed during the session as unsafe until the session no longer holds any temporary tables. * Beginning with MySQL 5.1.23: * When `FOUND_ROWS()' or `ROW_COUNT()' is used. (Bug#12092, Bug#30244) * When `USER()', `CURRENT_USER()', or `CURRENT_USER' is used. (Bug#28086) * Beginning with MySQL 5.1.24, when a statement refers to one or more system variables. (Bug#31168) Exception The following system variables, when used with session scope (only), do not cause the logging format to switch: * `auto_increment_increment' * `auto_increment_offset' * `character_set_client' * `character_set_connection' * `character_set_database' * `character_set_server' * `collation_connection' * `collation_database' * `collation_server' * `foreign_key_checks' * `identity' * `last_insert_id' * `lc_time_names' * `pseudo_thread_id' * `sql_auto_is_null' * `time_zone' * `timestamp' * `unique_checks' For information about determining system variable scope, see *Note using-system-variables::. For information about how replication treats `sql_mode', see *Note replication-features-variables::. * Beginning with MySQL 5.1.30, when one of the tables involved is a log table in the `mysql' database. * Beginning with MySQL 5.1.34, when the `LOAD_FILE()' function is used. (Bug#39701) *Note*: Starting with MySQL 5.1.20, a warning is generated if you try to execute a statement using statement-based logging that should be written using row-based logging. The warning is shown both in the client (in the output of *Note `SHOW WARNINGS': show-warnings.) and through the *Note `mysqld': mysqld. error log. A warning is added to the *Note `SHOW WARNINGS': show-warnings. table each time such a statement is executed. However, only the first statement that generated the warning for each client session is written to the error log to prevent flooding the log. Starting with MySQL 5.1.20, in addition to the decisions above, individual engines can also determine the logging format used when information in a table is updated. The logging capabilities of an individual engine can be defined as follows: * If an engine supports row-based logging, the engine is said to be _row-logging capable_. * If an engine supports statement-based logging, the engine is said to be _statement-logging capable_. A given storage engine can support either or both logging formats. The following table lists the logging formats supported by each storage engine. Storage Engine Row Logging Statement Logging Supported Supported `ARCHIVE' Yes Yes `BLACKHOLE' Yes Yes `CSV' Yes Yes `EXAMPLE' Yes No `FEDERATED' Yes Yes `HEAP' Yes Yes `InnoDB' Yes Yes when the transaction isolation level is `REPEATABLE READ' or `SERIALIZABLE'; No otherwise. `MyISAM' Yes Yes `MERGE' Yes Yes *Note `NDBCLUSTER': mysql-cluster. Yes No When determining the logging mode to be used, the capabilities of all the tables affected by the event are combined. The set of affected tables is then marked according to these rules: * A set of tables is defined as _row-logging restricted_ if the tables are row-logging capable but not statement-logging capable. * A set of tables is defined as _statement-logging restricted_ if the tables are statement-logging capable but not row-logging capable. Once the determination of the possible logging formats required by the statement is complete it is compared to the current `binlog_format' setting. The following table is used to decide how the information is recorded in the binary log or, if appropriate, whether an error is raised. In the table, a safe operation is defined as one that is deterministic. Several rules decide whether the statement is deterministic, as shown in the following table, where *SLR* stands for `statement-logging restricted' and *RLR* stands for `row-logging restricted'. A statement is _statement-logging restricted_ if one or more of the tables it accesses is not row-logging capable. Similarly, a statement is _row-logging restricted_ if any table accessed by the statement is not statement-logging capable. ConditionAction Safe/unsafe`binlog_format' SLR RLR Error/Warning Logged as Safe `STATEMENT' Yes Yes `Error: not loggable' Safe `STATEMENT' Yes No `STATEMENT' Safe `STATEMENT' No Yes `Error: not loggable' Safe `STATEMENT' No No `STATEMENT' Safe `MIXED' Yes Yes `Error: not loggable' Safe `MIXED' Yes No `STATEMENT' Safe `MIXED' No Yes `ROW' Safe `MIXED' No No `STATEMENT' Safe `ROW' Yes Yes `Error: not loggable' Safe `ROW' Yes No `Error: not loggable' Safe `ROW' No Yes `ROW' Safe `ROW' No No `ROW' Unsafe `STATEMENT' Yes Yes `Error: not loggable' Unsafe `STATEMENT' Yes No `Warning: `STATEMENT' unsafe' Unsafe `STATEMENT' No Yes `Error: not loggable' Unsafe `STATEMENT' No No `Warning: `STATEMENT' unsafe' Unsafe `MIXED' Yes Yes `Error: not loggable' Unsafe `MIXED' Yes No `Error: not loggable' Unsafe `MIXED' No Yes `ROW' Unsafe `MIXED' No No `ROW' Unsafe `ROW' Yes Yes `Error: not loggable' Unsafe `ROW' Yes No `Error: not loggable' Unsafe `ROW' No Yes `ROW' Unsafe `ROW' No No `ROW' When a warning is produced by the determination, a standard MySQL warning is produced (and is available using *Note `SHOW WARNINGS': show-warnings.). The information is also written to the *Note `mysqld': mysqld. error log. Only one error for each error instance per client connection is logged to prevent flooding the log. The log message includes the SQL statement that was attempted. If a slave server was started with `--log-warnings' enabled, the slave prints messages to the error log to provide information about its status, such as the binary log and relay log coordinates where it starts its job, when it is switching to another relay log, when it reconnects after a disconnect, and so forth.  File: manual.info, Node: binary-log-mysql-database, Prev: binary-log-mixed, Up: binary-log 6.2.4.4 Logging Format for Changes to `mysql' Database Tables ............................................................. The contents of the grant tables in the `mysql' database can be modified directly (for example, with *Note `INSERT': insert. or *Note `DELETE': delete.) or indirectly (for example, with *Note `GRANT': grant. or *Note `CREATE USER': create-user.). As of MySQL 5.1.17, statements that affect `mysql' database tables are written to the binary log using the following rules: * Data manipulation statements that change data in `mysql' database tables directly are logged according to the setting of the `binlog_format' system variable. This pertains to statements such as *Note `INSERT': insert, *Note `UPDATE': update, *Note `DELETE': delete, *Note `REPLACE': replace, *Note `DO': do, *Note `LOAD DATA INFILE': load-data, *Note `SELECT': select, and *Note `TRUNCATE TABLE': truncate-table. * Statements that change the `mysql' database indirectly are logged as statements regardless of the value of `binlog_format'. This pertains to statements such as *Note `GRANT': grant, *Note `REVOKE': revoke, *Note `SET PASSWORD': set-password, *Note `RENAME USER': rename-user, `CREATE' (all forms except *Note `CREATE TABLE ... SELECT': create-table.), `ALTER' (all forms), and `DROP' (all forms). *Note `CREATE TABLE ... SELECT': create-table. is a combination of data definition and data manipulation. The *Note `CREATE TABLE': create-table. part is logged using statement format and the *Note `SELECT': select. part is logged according to the value of `binlog_format'.  File: manual.info, Node: slow-query-log, Next: log-file-maintenance, Prev: binary-log, Up: server-logs 6.2.5 The Slow Query Log ------------------------ The slow query log consists of all SQL statements that took more than `long_query_time' seconds to execute and (as of MySQL 5.1.21) required at least `min_examined_row_limit' rows to be examined. The time to acquire the initial table locks is not counted as execution time. *Note `mysqld': mysqld. writes a statement to the slow query log after it has been executed and after all locks have been released, so log order might be different from execution order. The default value of `long_query_time' is 10. As of MySQL 5.1.21, the minimum value is 0, and a resolution of microseconds is supported when logging to a file. However, the microseconds part is ignored and only integer values are written when logging to tables. Prior to MySQL 5.1.21, the minimum value is 1, and the value for this variable must be an integer. Control the slow query log at server startup as follows: * Before 5.1.6, the slow query log destination is always a file. To enable the log, start *Note `mysqld': mysqld. with the `--log-slow-queries[=FILE_NAME]' option. * As of MySQL 5.1.6, the destination can be a file or a table, or both. Start *Note `mysqld': mysqld. with the `--log-slow-queries[=FILE_NAME]' option to enable the slow query log, and optionally use `--log-output' to specify the log destination (as described in *Note log-destinations::). * As of MySQL 5.1.12, as an alternative to `--log-slow-queries', use `--slow_query_log[={0|1}]' to specify the initial slow query log state. In this case, the default slow query log file name is used. With no argument or an argument of 1, `--slow_query_log' enables the log. With an argument of 0, this option disables the log. * As of MySQL 5.1.29, use `--slow_query_log[={0|1}]' to enable or disable the slow query log, and optionally `--slow_query_log_file=FILE_NAME' to specify a log file name. The `--log-slow-queries' option is deprecated. If you specify no name for the slow query log file, the default name is `HOST_NAME-slow.log'. The server creates the file in the data directory unless an absolute path name is given to specify a different directory. To control the slow log at runtime, use the global `slow_query_log' and `slow_query_log_file' system variables. Set `slow_query_log' to 0 (or `OFF') to disable the log or to 1 (or `ON') to enable it. Set `slow_query_log_file' to specify the name of the log file. If a log file already is open, it is closed and the new file is opened. When the slow query log is enabled, the server writes output to any destinations specified by the `--log-output' option or `log_output' system variable. If you enable the log, the server opens the log file and writes startup messages to it. However, further logging of queries to the file does not occur unless the `FILE' log destination is selected. If the destination is `NONE', no queries are written even if the slow query log is enabled. Setting the log file name has no effect on logging if the log destination value does not contain `FILE'. The slow query log can be used to find queries that take a long time to execute and are therefore candidates for optimization. However, examining a long slow query log can become a difficult task. To make this easier, you can process a slow query log file using the *Note `mysqldumpslow': mysqldumpslow. command to summarize the queries that appear in the log. See *Note mysqldumpslow::. In MySQL 5.1, queries that do not use indexes are logged in the slow query log if the `--log-queries-not-using-indexes' option is specified. See *Note server-options::. In MySQL 5.1, the `--log-slow-admin-statements' server option enables you to request logging of slow administrative statements such as *Note `OPTIMIZE TABLE': optimize-table, *Note `ANALYZE TABLE': analyze-table, and *Note `ALTER TABLE': alter-table. to the slow query log. Queries handled by the query cache are not added to the slow query log, nor are queries that would not benefit from the presence of an index because the table has zero rows or one row. Prior to MySQL 5.1.45, replication slaves did not write replicated queries to the slow query log, even if the same queries were written to the slow query log on the master. (Bug#23300) In MySQL 5.1.45 and later, this behavior can be overridden using the `--log-slow-slave-statements' option. The slow query log should be protected because logged statements might contain passwords. See *Note password-security-admin::.  File: manual.info, Node: log-file-maintenance, Prev: slow-query-log, Up: server-logs 6.2.6 Server Log Maintenance ---------------------------- MySQL Server can create a number of different log files to help you see what activity is taking place. See *Note server-logs::. However, you must clean up these files regularly to ensure that the logs do not take up too much disk space. When using MySQL with logging enabled, you may want to back up and remove old log files from time to time and tell MySQL to start logging to new files. See *Note backup-methods::. On a Linux (Red Hat) installation, you can use the `mysql-log-rotate' script for this. If you installed MySQL from an RPM distribution, this script should have been installed automatically. You should be careful with this script if you are using the binary log for replication. You should not remove binary logs until you are certain that their contents have been processed by all slaves. On other systems, you must install a short script yourself that you start from `cron' (or its equivalent) for handling log files. For the binary log, you can set the `expire_logs_days' system variable to expire binary log files automatically after a given number of days (see *Note server-system-variables::). If you are using replication, you should set the variable no lower than the maximum number of days your slaves might lag behind the master. To remove binary logs on demand, use the *Note `PURGE BINARY LOGS': purge-binary-logs. statement (see *Note purge-binary-logs::). You can force MySQL to start using new log files by flushing the logs. Log flushing occurs when you issue a *Note `FLUSH LOGS': flush. statement or execute a *Note `mysqladmin flush-logs': mysqladmin, *Note `mysqladmin refresh': mysqladmin, *Note `mysqldump --flush-logs': mysqldump, or *Note `mysqldump --master-data': mysqldump. command. See *Note flush::, *Note mysqladmin::, and *Note mysqldump::. In addition, the binary log is flushed when its size reaches the value of the `max_binlog_size' system variable. A log-flushing operation does the following: * If general query logging or slow query logging to a log file is enabled, the server closes and reopens the general query log file or slow query log file. * If binary logging is enabled, the server closes the current binary log file and opens a new log file with the next sequence number. * If the server was started with the `--log-error' option to cause the error log to be written to a file, the result of a log-flushing operation is version dependent: * As of MySQL 5.1.51, the server closes and reopens the log file. * Prior to MySQL 5.1.51, the server renames the current log file with the suffix `-old', then creates a new empty log file. The server creates a new binary log file when you flush the logs. However, it just closes and reopens the general and slow query log files. To cause new files to be created on Unix, rename the current logs before flushing them. At flush time, the server opens new logs with the original names. For example, if the general and slow query logs are named `mysql.log' and `mysql-slow.log', you can use a series of commands like this: shell> cd MYSQL-DATA-DIRECTORY shell> mv mysql.log mysql.old shell> mv mysql-slow.log mysql-slow.old shell> mysqladmin flush-logs On Windows, use `rename' rather than `mv'. At this point, you can make a backup of `mysql.old' and `mysql-slow.old' and then remove them from disk. As of MySQL 5.1.12, you can rename the general query log or slow query log at runtime by disabling the log: SET GLOBAL general_log = 'OFF'; SET GLOBAL slow_query_log = 'OFF'; With the logs disabled, rename the log files externally; for example, from the command line. Then enable the logs again: SET GLOBAL general_log = 'ON'; SET GLOBAL slow_query_log = 'ON'; This method works on any platform and does not require a server restart. For older versions of MySQL, you cannot rename certain log files on Windows while the server has them open. Before MySQL 5.1.3, this restriction applies to all log files. You must stop the server, rename the file, then restart the server to create a new log file. From 5.1.4 to 5.1.50, the restriction applies only to the error log file. To rename the error log file, a stop and restart can be avoided by flushing the logs to cause the server to rename the current log file with the suffix `-old' and create a new empty error log file. For further information, see *Note error-log::.  File: manual.info, Node: security, Next: privilege-system, Prev: server-logs, Up: server-administration 6.3 General Security Issues =========================== * Menu: * security-guidelines:: General Security Guidelines * password-security:: Password Security in MySQL * security-against-attack:: Making MySQL Secure Against Attackers * privileges-options:: Security-Related `mysqld' Options * load-data-local:: Security Issues with `LOAD DATA LOCAL' * changing-mysql-user:: How to Run MySQL as a Normal User This section describes some general security issues to be aware of and what you can do to make your MySQL installation more secure against attack or misuse. For information specifically about the access control system that MySQL uses for setting up user accounts and checking database access, see *Note privilege-system::. For answers to some questions that are often asked about MySQL Server security issues, see *Note faqs-security::.  File: manual.info, Node: security-guidelines, Next: password-security, Prev: security, Up: security 6.3.1 General Security Guidelines --------------------------------- Anyone using MySQL on a computer connected to the Internet should read this section to avoid the most common security mistakes. In discussing security, we emphasize the necessity of fully protecting the entire server host (not just the MySQL server) against all types of applicable attacks: eavesdropping, altering, playback, and denial of service. We do not cover all aspects of availability and fault tolerance here. MySQL uses security based on Access Control Lists (ACLs) for all connections, queries, and other operations that users can attempt to perform. There is also support for SSL-encrypted connections between MySQL clients and servers. Many of the concepts discussed here are not specific to MySQL at all; the same general ideas apply to almost all applications. When running MySQL, follow these guidelines whenever possible: * *Do not ever give anyone (except MySQL `root' accounts) access to the `user' table in the `mysql' database!* This is critical. * Learn the MySQL access privilege system. The *Note `GRANT': grant. and *Note `REVOKE': revoke. statements are used for controlling access to MySQL. Do not grant more privileges than necessary. Never grant privileges to all hosts. Checklist: * Try `mysql -u root'. If you are able to connect successfully to the server without being asked for a password, anyone can connect to your MySQL server as the MySQL `root' user with full privileges! Review the MySQL installation instructions, paying particular attention to the information about setting a `root' password. See *Note default-privileges::. * Use the *Note `SHOW GRANTS': show-grants. statement to check which accounts have access to what. Then use the *Note `REVOKE': revoke. statement to remove those privileges that are not necessary. * Do not store any plaintext passwords in your database. If your computer becomes compromised, the intruder can take the full list of passwords and use them. Instead, use `MD5()', `SHA1()', or some other one-way hashing function and store the hash value. * Do not choose passwords from dictionaries. Special programs exist to break passwords. Even passwords like `xfish98' are very bad. Much better is `duag98' which contains the same word `fish' but typed one key to the left on a standard QWERTY keyboard. Another method is to use a password that is taken from the first characters of each word in a sentence (for example, `Mary had a little lamb' results in a password of `Mhall'). The password is easy to remember and type, but difficult to guess for someone who does not know the sentence. * Invest in a firewall. This protects you from at least 50% of all types of exploits in any software. Put MySQL behind the firewall or in a demilitarized zone (DMZ). Checklist: * Try to scan your ports from the Internet using a tool such as `nmap'. MySQL uses port 3306 by default. This port should not be accessible from untrusted hosts. Another simple way to check whether or not your MySQL port is open is to try the following command from some remote machine, where SERVER_HOST is the host name or IP address of the host on which your MySQL server runs: shell> telnet SERVER_HOST 3306 If you get a connection and some garbage characters, the port is open, and should be closed on your firewall or router, unless you really have a good reason to keep it open. If `telnet' hangs or the connection is refused, the port is blocked, which is how you want it to be. * Do not trust any data entered by users of your applications. They can try to trick your code by entering special or escaped character sequences in Web forms, URLs, or whatever application you have built. Be sure that your application remains secure if a user enters something like ``; DROP DATABASE mysql;''. This is an extreme example, but large security leaks and data loss might occur as a result of hackers using similar techniques, if you do not prepare for them. A common mistake is to protect only string data values. Remember to check numeric data as well. If an application generates a query such as `SELECT * FROM table WHERE ID=234' when a user enters the value `234', the user can enter the value `234 OR 1=1' to cause the application to generate the query `SELECT * FROM table WHERE ID=234 OR 1=1'. As a result, the server retrieves every row in the table. This exposes every row and causes excessive server load. The simplest way to protect from this type of attack is to use single quotation marks around the numeric constants: `SELECT * FROM table WHERE ID='234''. If the user enters extra information, it all becomes part of the string. In a numeric context, MySQL automatically converts this string to a number and strips any trailing nonnumeric characters from it. Sometimes people think that if a database contains only publicly available data, it need not be protected. This is incorrect. Even if it is permissible to display any row in the database, you should still protect against denial of service attacks (for example, those that are based on the technique in the preceding paragraph that causes the server to waste resources). Otherwise, your server becomes unresponsive to legitimate users. Checklist: * Try to enter single and double quotation marks (``''' and ``"'') in all of your Web forms. If you get any kind of MySQL error, investigate the problem right away. * Try to modify dynamic URLs by adding `%22' (``"''), `%23' (``#''), and `%27' (``''') to them. * Try to modify data types in dynamic URLs from numeric to character types using the characters shown in the previous examples. Your application should be safe against these and similar attacks. * Try to enter characters, spaces, and special symbols rather than numbers in numeric fields. Your application should remove them before passing them to MySQL or else generate an error. Passing unchecked values to MySQL is very dangerous! * Check the size of data before passing it to MySQL. * Have your application connect to the database using a user name different from the one you use for administrative purposes. Do not give your applications any access privileges they do not need. * Many application programming interfaces provide a means of escaping special characters in data values. Properly used, this prevents application users from entering values that cause the application to generate statements that have a different effect than you intend: * MySQL C API: Use the *Note `mysql_real_escape_string()': mysql-real-escape-string. API call. * MySQL++: Use the `escape' and `quote' modifiers for query streams. * PHP: Use the `mysql_real_escape_string()' function (available as of PHP 4.3.0, prior to that PHP version use `mysql_escape_string()', and prior to PHP 4.0.3, use `addslashes()' ). Note that only `mysql_real_escape_string()' is character set-aware; the other functions can be `bypassed' when using (invalid) multi-byte character sets. In PHP 5, you can use the `mysqli' extension, which supports the improved MySQL authentication protocol and passwords, as well as prepared statements with placeholders. * Perl DBI: Use placeholders or the `quote()' method. * Ruby DBI: Use placeholders or the `quote()' method. * Java JDBC: Use a `PreparedStatement' object and placeholders. Other programming interfaces might have similar capabilities. * Do not transmit plain (unencrypted) data over the Internet. This information is accessible to everyone who has the time and ability to intercept it and use it for their own purposes. Instead, use an encrypted protocol such as SSL or SSH. MySQL supports internal SSL connections as of version 4.0. Another technique is to use SSH port-forwarding to create an encrypted (and compressed) tunnel for the communication. * Learn to use the `tcpdump' and `strings' utilities. In most cases, you can check whether MySQL data streams are unencrypted by issuing a command like the following: shell> tcpdump -l -i eth0 -w - src or dst port 3306 | strings This works under Linux and should work with small modifications under other systems. *Warning*: If you do not see plaintext data, this does not always mean that the information actually is encrypted. If you need high security, you should consult with a security expert.  File: manual.info, Node: password-security, Next: security-against-attack, Prev: security-guidelines, Up: security 6.3.2 Password Security in MySQL -------------------------------- * Menu: * password-security-admin:: Administrator Guidelines for Password Security * password-security-user:: End-User Guidelines for Password Security * password-hashing:: Password Hashing in MySQL * application-password-use:: Implications of Password Hashing Changes in MySQL 4.1 for Application Programs Passwords occur in several contexts within MySQL. The following sections provide guidelines that enable administrators and end users to keep these passwords secure and avoid exposing them. There is also a discussion of how MySQL uses password hashing internally.  File: manual.info, Node: password-security-admin, Next: password-security-user, Prev: password-security, Up: password-security 6.3.2.1 Administrator Guidelines for Password Security ...................................................... Database administrators should use the following guidelines to keep passwords secure. MySQL stores passwords for user accounts in the `mysql.user' table. Access to this table should never be granted to any nonadministrative accounts. A user who has access to modify the plugin directory (the value of the `plugin_dir' system variable) or the `my.cnf' file that specifies the location of the plugin directory can replace plugins and modify the capabilities provided by plugins. Passwords can appear as plain text in SQL statements such as *Note `CREATE USER': create-user, *Note `GRANT': grant, and *Note `SET PASSWORD': set-password, or statements that invoke the `PASSWORD()' function. If these statements are logged by the MySQL server, the passwords become available to anyone with access to the logs. This applies to the general query log, the slow query log, and the binary log (see *Note server-logs::). To guard against unwarranted exposure to log files, they should be located in a directory that restricts access to only the server and the database administrator. If you log to tables in the `mysql' database, access to the tables should never be granted to any nonadministrative accounts. Replication slaves store the password for the replication master in the `master.info' file. Access to this file should be restricted to the database administrator. Database backups that include tables or log files containing passwords should be protected using a restricted access mode.  File: manual.info, Node: password-security-user, Next: password-hashing, Prev: password-security-admin, Up: password-security 6.3.2.2 End-User Guidelines for Password Security ................................................. MySQL users should use the following guidelines to keep passwords secure. When you run a client program to connect to the MySQL server, it is inadvisable to specify your password in a way that exposes it to discovery by other users. The methods you can use to specify your password when you run client programs are listed here, along with an assessment of the risks of each method. In short, the safest methods are to have the client program prompt for the password or to specify the password in a properly protected option file. * Use a `-pYOUR_PASS' or `--password=YOUR_PASS' option on the command line. For example: shell> mysql -u francis -pfrank DB_NAME This is convenient _but insecure_, because your password becomes visible to system status programs such as `ps' that may be invoked by other users to display command lines. MySQL clients typically overwrite the command-line password argument with zeros during their initialization sequence. However, there is still a brief interval during which the value is visible. Also, on some systems this overwriting strategy is ineffective and the password remains visible to `ps'. (SystemV Unix systems and perhaps others are subject to this problem.) If your operating environment is set up to display your current command in the title bar of your terminal window, the password remains visible as long as the command is running, even if the command has scrolled out of view in the window content area. * Use the `-p' or `--password' option on the command line with no password value specified. In this case, the client program solicits the password interactively: shell> mysql -u francis -p DB_NAME Enter password: ******** The ``*'' characters indicate where you enter your password. The password is not displayed as you enter it. It is more secure to enter your password this way than to specify it on the command line because it is not visible to other users. However, this method of entering a password is suitable only for programs that you run interactively. If you want to invoke a client from a script that runs noninteractively, there is no opportunity to enter the password from the keyboard. On some systems, you may even find that the first line of your script is read and interpreted (incorrectly) as your password. * Store your password in an option file. For example, on Unix you can list your password in the `[client]' section of the `.my.cnf' file in your home directory: [client] password=your_pass To keep the password safe, the file should not be accessible to anyone but yourself. To ensure this, set the file access mode to `400' or `600'. For example: shell> chmod 600 .my.cnf To name from the command line a specific option file containing the password, use the `--defaults-file=FILE_NAME' option, where `file_name' is the full path name to the file. For example: shell> mysql --defaults-file=/home/francis/mysql-opts *Note option-files::, discusses option files in more detail. * Store your password in the `MYSQL_PWD' environment variable. See *Note environment-variables::. This method of specifying your MySQL password must be considered _extremely insecure_ and should not be used. Some versions of `ps' include an option to display the environment of running processes. If you set `MYSQL_PWD', your password is exposed to any other user who runs `ps'. Even on systems without such a version of `ps', it is unwise to assume that there are no other methods by which users can examine process environments. On Unix, the *Note `mysql': mysql. client writes a record of executed statements to a history file (see *Note mysql-history-file::). By default, this file is named `.mysql_history' and is created in your home directory. Passwords can appear as plain text in SQL statements such as *Note `CREATE USER': create-user, *Note `GRANT': grant, and *Note `SET PASSWORD': set-password, so if you use these statements, they are logged in the history file. To keep this file safe, use a restrictive access mode, the same way as described earlier for the `.my.cnf' file. If your command interpreter is configured to maintain a history, any file in which the commands are saved will contain MySQL passwords entered on the command line. For example, `bash' uses `~/.bash_history'. Any such file should have a restrictive access mode.  File: manual.info, Node: password-hashing, Next: application-password-use, Prev: password-security-user, Up: password-security 6.3.2.3 Password Hashing in MySQL ................................. MySQL user accounts are listed in the `user' table of the `mysql' database. Each MySQL account is assigned a password, although what is stored in the `Password' column of the `user' table is not the plaintext version of the password, but a hash value computed from it. Password hash values are computed by the `PASSWORD()' function. MySQL uses passwords in two phases of client/server communication: * When a client attempts to connect to the server, there is an initial authentication step in which the client must present a password that has a hash value matching the hash value stored in the `user' table for the account that the client wants to use. * After the client connects, it can (if it has sufficient privileges) set or change the password hashes for accounts listed in the `user' table. The client can do this by using the `PASSWORD()' function to generate a password hash, or by using the *Note `GRANT': grant. or *Note `SET PASSWORD': set-password. statements. In other words, the server _uses_ hash values during authentication when a client first attempts to connect. The server _generates_ hash values if a connected client invokes the `PASSWORD()' function or uses a *Note `GRANT': grant. or *Note `SET PASSWORD': set-password. statement to set or change a password. The password hashing mechanism was updated in MySQL 4.1 to provide better security and to reduce the risk of passwords being intercepted. However, this new mechanism is understood only by MySQL 4.1 (and newer) servers and clients, which can result in some compatibility problems. A 4.1 or newer client can connect to a pre-4.1 server, because the client understands both the old and new password hashing mechanisms. However, a pre-4.1 client that attempts to connect to a 4.1 or newer server may run into difficulties. For example, a 3.23 *Note `mysql': mysql. client that attempts to connect to a 5.1 server may fail with the following error message: shell> mysql -h localhost -u root Client does not support authentication protocol requested by server; consider upgrading MySQL client Another common example of this phenomenon occurs for attempts to use the older PHP `mysql' extension after upgrading to MySQL 4.1 or newer. (See *Note apis-php-problems::.) The following discussion describes the differences between the old and new password mechanisms, and what you should do if you upgrade your server but need to maintain backward compatibility with pre-4.1 clients. Additional information can be found in *Note old-client::. This information is of particular importance to PHP programmers migrating MySQL databases from version 4.0 or lower to version 4.1 or higher. *Note*: This discussion contrasts 4.1 behavior with pre-4.1 behavior, but the 4.1 behavior described here actually begins with 4.1.1. MySQL 4.1.0 is an `odd' release because it has a slightly different mechanism than that implemented in 4.1.1 and up. Differences between 4.1.0 and more recent versions are described further in MySQL 5.0 Reference Manual. Prior to MySQL 4.1, password hashes computed by the `PASSWORD()' function are 16 bytes long. Such hashes look like this: mysql> SELECT PASSWORD('mypass'); +--------------------+ | PASSWORD('mypass') | +--------------------+ | 6f8c114b58f2ce9e | +--------------------+ The `Password' column of the `user' table (in which these hashes are stored) also is 16 bytes long before MySQL 4.1. As of MySQL 4.1, the `PASSWORD()' function has been modified to produce a longer 41-byte hash value: mysql> SELECT PASSWORD('mypass'); +-------------------------------------------+ | PASSWORD('mypass') | +-------------------------------------------+ | *6C8989366EAF75BB670AD8EA7A7FC1176A95CEF4 | +-------------------------------------------+ Accordingly, the `Password' column in the `user' table also must be 41 bytes long to store these values: * If you perform a new installation of MySQL 5.1, the `Password' column is made 41 bytes long automatically. * Upgrading from MySQL 4.1 (4.1.1 or later in the 4.1 series) to MySQL 5.1 should not give rise to any issues in this regard because both versions use the same password hashing mechanism. If you wish to upgrade an older release of MySQL to version 5.1, you should upgrade to version 4.1 first, then upgrade the 4.1 installation to 5.1. A widened `Password' column can store password hashes in both the old and new formats. The format of any given password hash value can be determined two ways: * The obvious difference is the length (16 bytes versus 41 bytes). * A second difference is that password hashes in the new format always begin with a ``*'' character, whereas passwords in the old format never do. The longer password hash format has better cryptographic properties, and client authentication based on long hashes is more secure than that based on the older short hashes. The differences between short and long password hashes are relevant both for how the server uses passwords during authentication and for how it generates password hashes for connected clients that perform password-changing operations. The way in which the server uses password hashes during authentication is affected by the width of the `Password' column: * If the column is short, only short-hash authentication is used. * If the column is long, it can hold either short or long hashes, and the server can use either format: * Pre-4.1 clients can connect, although because they know only about the old hashing mechanism, they can authenticate only using accounts that have short hashes. * 4.1 and later clients can authenticate using accounts that have short or long hashes. Even for short-hash accounts, the authentication process is actually a bit more secure for 4.1 and later clients than for older clients. In terms of security, the gradient from least to most secure is: * Pre-4.1 client authenticating with short password hash * 4.1 or later client authenticating with short password hash * 4.1 or later client authenticating with long password hash The way in which the server generates password hashes for connected clients is affected by the width of the `Password' column and by the `--old-passwords' option. A 4.1 or later server generates long hashes only if certain conditions are met: The `Password' column must be wide enough to hold long values and the `--old-passwords' option must not be given. These conditions apply as follows: * The `Password' column must be wide enough to hold long hashes (41 bytes). If the column has not been updated and still has the pre-4.1 width of 16 bytes, the server notices that long hashes cannot fit into it and generates only short hashes when a client performs password-changing operations using `PASSWORD()', *Note `GRANT': grant, or *Note `SET PASSWORD': set-password. This is the behavior that occurs if you have upgraded to 4.1 but have not yet run the *Note `mysql_upgrade': mysql-upgrade. program to widen the `Password' column. * If the `Password' column is wide, it can store either short or long password hashes. In this case, `PASSWORD()', *Note `GRANT': grant, and *Note `SET PASSWORD': set-password. generate long hashes unless the server was started with the `--old-passwords' option. That option forces the server to generate short password hashes instead. The purpose of the `--old-passwords' option is to enable you to maintain backward compatibility with pre-4.1 clients under circumstances where the server would otherwise generate long password hashes. The option does not affect authentication (4.1 and later clients can still use accounts that have long password hashes), but it does prevent creation of a long password hash in the `user' table as the result of a password-changing operation. Were that to occur, the account no longer could be used by pre-4.1 clients. Without the `--old-passwords' option, the following undesirable scenario is possible: * An old client connects to an account that has a short password hash. * The client changes its own password. Without `--old-passwords', this results in the account having a long password hash. * The next time the old client attempts to connect to the account, it cannot, because the account has a long password hash that requires the new hashing mechanism during authentication. (Once an account has a long password hash in the user table, only 4.1 and later clients can authenticate for it, because pre-4.1 clients do not understand long hashes.) This scenario illustrates that, if you must support older pre-4.1 clients, it is dangerous to run a 4.1 or newer server without using the `--old-passwords' option. By running the server with `--old-passwords', password-changing operations do not generate long password hashes and thus do not cause accounts to become inaccessible to older clients. (Those clients cannot inadvertently lock themselves out by changing their password and ending up with a long password hash.) The downside of the `--old-passwords' option is that any passwords you create or change use short hashes, even for 4.1 clients. Thus, you lose the additional security provided by long password hashes. If you want to create an account that has a long hash (for example, for use by 4.1 clients), you must do so while running the server without `--old-passwords'. The following scenarios are possible for running a 4.1 or later server: *Scenario 1:* Short `Password' column in user table: * Only short hashes can be stored in the `Password' column. * The server uses only short hashes during client authentication. * For connected clients, password hash-generating operations involving `PASSWORD()', *Note `GRANT': grant, or *Note `SET PASSWORD': set-password. use short hashes exclusively. Any change to an account's password results in that account having a short password hash. * The `--old-passwords' option can be used but is superfluous because with a short `Password' column, the server generates only short password hashes anyway. *Scenario 2:* Long `Password' column; server not started with `--old-passwords' option: * Short or long hashes can be stored in the `Password' column. * 4.1 and later clients can authenticate using accounts that have short or long hashes. * Pre-4.1 clients can authenticate only using accounts that have short hashes. * For connected clients, password hash-generating operations involving `PASSWORD()', *Note `GRANT': grant, or *Note `SET PASSWORD': set-password. use long hashes exclusively. A change to an account's password results in that account having a long password hash. As indicated earlier, a danger in this scenario is that it is possible for accounts that have a short password hash to become inaccessible to pre-4.1 clients. A change to such an account's password made using *Note `GRANT': grant, `PASSWORD()', or *Note `SET PASSWORD': set-password. results in the account being given a long password hash. From that point on, no pre-4.1 client can authenticate to that account until the client upgrades to 4.1. To deal with this problem, you can change a password in a special way. For example, normally you use *Note `SET PASSWORD': set-password. as follows to change an account password: SET PASSWORD FOR 'SOME_USER'@'SOME_HOST' = PASSWORD('mypass'); To change the password but create a short hash, use the `OLD_PASSWORD()' function instead: SET PASSWORD FOR 'SOME_USER'@'SOME_HOST' = OLD_PASSWORD('mypass'); `OLD_PASSWORD()' is useful for situations in which you explicitly want to generate a short hash. *Scenario 3:* Long `Password' column; 4.1 or newer server started with `--old-passwords' option: * Short or long hashes can be stored in the `Password' column. * 4.1 and later clients can authenticate for accounts that have short or long hashes (but note that it is possible to create long hashes only when the server is started without `--old-passwords'). * Pre-4.1 clients can authenticate only for accounts that have short hashes. * For connected clients, password hash-generating operations involving `PASSWORD()', *Note `GRANT': grant, or *Note `SET PASSWORD': set-password. use short hashes exclusively. Any change to an account's password results in that account having a short password hash. In this scenario, you cannot create accounts that have long password hashes, because the `--old-passwords' option prevents generation of long hashes. Also, if you create an account with a long hash before using the `--old-passwords' option, changing the account's password while `--old-passwords' is in effect results in the account being given a short password, causing it to lose the security benefits of a longer hash. The disadvantages for these scenarios may be summarized as follows: In scenario 1, you cannot take advantage of longer hashes that provide more secure authentication. In scenario 2, accounts with short hashes become inaccessible to pre-4.1 clients if you change their passwords without explicitly using `OLD_PASSWORD()'. In scenario 3, `--old-passwords' prevents accounts with short hashes from becoming inaccessible, but password-changing operations cause accounts with long hashes to revert to short hashes, and you cannot change them back to long hashes while `--old-passwords' is in effect.  File: manual.info, Node: application-password-use, Prev: password-hashing, Up: password-security 6.3.2.4 Implications of Password Hashing Changes in MySQL 4.1 for Application Programs ...................................................................................... An upgrade to MySQL version 4.1 or later can cause compatibility issues for applications that use `PASSWORD()' to generate passwords for their own purposes. Applications really should not do this, because `PASSWORD()' should be used only to manage passwords for MySQL accounts. But some applications use `PASSWORD()' for their own purposes anyway. If you upgrade to 4.1 or later from a pre-4.1 version of MySQL and run the server under conditions where it generates long password hashes, an application using `PASSWORD()' for its own passwords breaks. The recommended course of action in such cases is to modify the application to use another function, such as `SHA1()' or `MD5()', to produce hashed values. If that is not possible, you can use the `OLD_PASSWORD()' function, which is provided for generate short hashes in the old format. However, you should note that `OLD_PASSWORD()' may one day no longer be supported. If the server is running under circumstances where it generates short hashes, `OLD_PASSWORD()' is available but is equivalent to `PASSWORD()'. PHP programmers migrating their MySQL databases from version 4.0 or lower to version 4.1 or higher should see *Note apis-php::.  File: manual.info, Node: security-against-attack, Next: privileges-options, Prev: password-security, Up: security 6.3.3 Making MySQL Secure Against Attackers ------------------------------------------- When you connect to a MySQL server, you should use a password. The password is not transmitted in clear text over the connection. Password handling during the client connection sequence was upgraded in MySQL 4.1.1 to be very secure. If you are still using pre-4.1.1-style passwords, the encryption algorithm is not as strong as the newer algorithm. With some effort, a clever attacker who can sniff the traffic between the client and the server can crack the password. (See *Note password-hashing::, for a discussion of the different password handling methods.) All other information is transferred as text, and can be read by anyone who is able to watch the connection. If the connection between the client and the server goes through an untrusted network, and you are concerned about this, you can use the compressed protocol to make traffic much more difficult to decipher. You can also use MySQL's internal SSL support to make the connection even more secure. See *Note secure-connections::. Alternatively, use SSH to get an encrypted TCP/IP connection between a MySQL server and a MySQL client. You can find an Open Source SSH client at `http://www.openssh.org/', and a commercial SSH client at `http://www.ssh.com/'. To make a MySQL system secure, you should strongly consider the following suggestions: * Require all MySQL accounts to have a password. A client program does not necessarily know the identity of the person running it. It is common for client/server applications that the user can specify any user name to the client program. For example, anyone can use the *Note `mysql': mysql. program to connect as any other person simply by invoking it as `mysql -u OTHER_USER DB_NAME' if OTHER_USER has no password. If all accounts have a password, connecting using another user's account becomes much more difficult. For a discussion of methods for setting passwords, see *Note assigning-passwords::. * Never run the MySQL server as the Unix `root' user. This is extremely dangerous, because any user with the `FILE' privilege is able to cause the server to create files as `root' (for example, `~root/.bashrc'). To prevent this, *Note `mysqld': mysqld. refuses to run as `root' unless that is specified explicitly using the `--user=root' option. *Note `mysqld': mysqld. can (and should) be run as an ordinary, unprivileged user instead. You can create a separate Unix account named `mysql' to make everything even more secure. Use this account only for administering MySQL. To start *Note `mysqld': mysqld. as a different Unix user, add a `user' option that specifies the user name in the `[mysqld]' group of the `my.cnf' option file where you specify server options. For example: [mysqld] user=mysql This causes the server to start as the designated user whether you start it manually or by using *Note `mysqld_safe': mysqld-safe. or *Note `mysql.server': mysql-server. For more details, see *Note changing-mysql-user::. Running *Note `mysqld': mysqld. as a Unix user other than `root' does not mean that you need to change the `root' user name in the `user' table. _User names for MySQL accounts have nothing to do with user names for Unix accounts_. * Do not permit the use of symlinks to tables. (This capability can be disabled with the `--skip-symbolic-links' option.) This is especially important if you run *Note `mysqld': mysqld. as `root', because anyone that has write access to the server's data directory then could delete any file in the system! See *Note symbolic-links-to-tables::. * Make sure that the only Unix user account with read or write privileges in the database directories is the account that is used for running *Note `mysqld': mysqld. * Do not grant the `PROCESS' or `SUPER' privilege to nonadministrative users. The output of *Note `mysqladmin processlist': mysqladmin. and *Note `SHOW PROCESSLIST': show-processlist. shows the text of any statements currently being executed, so any user who is permitted to see the server process list might be able to see statements issued by other users such as `UPDATE user SET password=PASSWORD('not_secure')'. *Note `mysqld': mysqld. reserves an extra connection for users who have the `SUPER' privilege, so that a MySQL `root' user can log in and check server activity even if all normal connections are in use. The `SUPER' privilege can be used to terminate client connections, change server operation by changing the value of system variables, and control replication servers. * Do not grant the `FILE' privilege to nonadministrative users. Any user that has this privilege can write a file anywhere in the file system with the privileges of the *Note `mysqld': mysqld. daemon. To make this a bit safer, files generated with *Note `SELECT ... INTO OUTFILE': select. do not overwrite existing files and are writable by everyone. The `FILE' privilege may also be used to read any file that is world-readable or accessible to the Unix user that the server runs as. With this privilege, you can read any file into a database table. This could be abused, for example, by using *Note `LOAD DATA': load-data. to load `/etc/passwd' into a table, which then can be displayed with *Note `SELECT': select. * Stored programs and views should be written using the security guidelines discussed in *Note stored-programs-security::. * If you do not trust your DNS, you should use IP addresses rather than host names in the grant tables. In any case, you should be very careful about creating grant table entries using host name values that contain wildcards. * If you want to restrict the number of connections permitted to a single account, you can do so by setting the `max_user_connections' variable in *Note `mysqld': mysqld. The *Note `GRANT': grant. statement also supports resource control options for limiting the extent of server use permitted to an account. See *Note grant::. * If the plugin directory is writable by the server, it may be possible for a user to write executable code to a file in the directory using *Note `SELECT ... INTO DUMPFILE': select. This can be prevented by making `plugin_dir' read only to the server or by setting `--secure-file-priv' to a directory where *Note `SELECT': select. writes can be made safely.  File: manual.info, Node: privileges-options, Next: load-data-local, Prev: security-against-attack, Up: security 6.3.4 Security-Related `mysqld' Options --------------------------------------- The following *Note `mysqld': mysqld. options affect security: *Security Option/Variable Summary* Name Cmd-Line Option file System Var Status Var Var Scope Dynamic allow-suspicious-udfsYes Yes automatic_sp_privileges Yes Global Yes chroot Yes Yes des-key-file Yes Yes local_infile Yes Global Yes local-infile Yes Yes - _Variable_: local_infile old-passwords Yes Yes Both Yes - _Variable_: Yes Both Yes old_passwords safe-show-databaseYes Yes Yes Global Yes safe-user-createYes Yes secure-auth Yes Yes Global Yes - _Variable_: Yes Global Yes secure_auth secure-file-privYes Yes Global No - _Variable_: Yes Global No secure_file_priv skip-grant-tablesYes Yes skip-name-resolveYes Yes Global No - _Variable_: Yes Global No skip_name_resolve skip-networkingYes Yes Global No - _Variable_: Yes Global No skip_networking skip-show-databaseYes Yes Global No - _Variable_: Yes Global No skip_show_database * `--allow-suspicious-udfs' This option controls whether user-defined functions that have only an `xxx' symbol for the main function can be loaded. By default, the option is off and only UDFs that have at least one auxiliary symbol can be loaded; this prevents attempts at loading functions from shared object files other than those containing legitimate UDFs. See *Note udf-security::. * `--local-infile[={0|1}]' If you start the server with `--local-infile=0', clients cannot use `LOCAL' in *Note `LOAD DATA': load-data. statements. See *Note load-data-local::. * `--old-passwords' Force the server to generate short (pre-4.1) password hashes for new passwords. This is useful for compatibility when the server must support older client programs. See *Note password-hashing::. * `--safe-user-create' If this option is enabled, a user cannot create new MySQL users by using the *Note `GRANT': grant. statement unless the user has the `INSERT' privilege for the `mysql.user' table or any column in the table. If you want a user to have the ability to create new users that have those privileges that the user has the right to grant, you should grant the user the following privilege: GRANT INSERT(user) ON mysql.user TO 'USER_NAME'@'HOST_NAME'; This ensures that the user cannot change any privilege columns directly, but has to use the *Note `GRANT': grant. statement to give privileges to other users. * `--secure-auth' Disallow authentication for accounts that have old (pre-4.1) passwords. The *Note `mysql': mysql. client also has a `--secure-auth' option, which prevents connections to a server if the server requires a password in old format for the client account. * `--secure-file-priv=PATH' This option limits the effect of the `LOAD_FILE()' function and the *Note `LOAD DATA': load-data. and *Note `SELECT ... INTO OUTFILE': select. statements to work only with files in the specified directory. This option was added in MySQL 5.1.17. * `--skip-grant-tables' This option causes the server to start without using the privilege system at all, which gives anyone with access to the server _unrestricted access to all databases_. You can cause a running server to start using the grant tables again by executing *Note `mysqladmin flush-privileges': mysqladmin. or *Note `mysqladmin reload': mysqladmin. command from a system shell, or by issuing a MySQL *Note `FLUSH PRIVILEGES': flush. statement after connecting to the server. This option also suppresses loading of plugins that were installed with the *Note `INSTALL PLUGIN': install-plugin. statement, user-defined functions (UDFs), and, beginning with MySQL 5.1.17, scheduled events. To cause plugins to be loaded anyway, use the `--plugin-load' option. `--skip-grant-tables' is unavailable if MySQL was configured with the `--disable-grant-options' option. See *Note source-configuration-options::. * `--skip-merge' Disable the `MERGE' storage engine. This option was added in MySQL 5.1.12 and removed in 5.1.14. * `--skip-name-resolve' Host names are not resolved. All `Host' column values in the grant tables must be IP addresses or `localhost'. * `--skip-networking' Do not permit TCP/IP connections over the network. All connections to *Note `mysqld': mysqld. must be made using Unix socket files. * `--skip-show-database' With this option, the *Note `SHOW DATABASES': show-databases. statement is permitted only to users who have the `SHOW DATABASES' privilege, and the statement displays all database names. Without this option, *Note `SHOW DATABASES': show-databases. is permitted to all users, but displays each database name only if the user has the `SHOW DATABASES' privilege or some privilege for the database. Note that any global privilege is a privilege for the database. * `--ssl*' Options that begin with `--ssl' specify whether to permit clients to connect using SSL and indicate where to find SSL keys and certificates. See *Note ssl-options::.  File: manual.info, Node: load-data-local, Next: changing-mysql-user, Prev: privileges-options, Up: security 6.3.5 Security Issues with `LOAD DATA LOCAL' -------------------------------------------- The *Note `LOAD DATA': load-data. statement can load a file that is located on the server host, or it can load a file that is located on the client host when the `LOCAL' keyword is specified. There are two potential security issues with supporting the `LOCAL' version of *Note `LOAD DATA': load-data. statements: * The transfer of the file from the client host to the server host is initiated by the MySQL server. In theory, a patched server could be built that would tell the client program to transfer a file of the server's choosing rather than the file named by the client in the *Note `LOAD DATA': load-data. statement. Such a server could access any file on the client host to which the client user has read access. * In a Web environment where the clients are connecting from a Web server, a user could use *Note `LOAD DATA LOCAL': load-data. to read any files that the Web server process has read access to (assuming that a user could run any command against the SQL server). In this environment, the client with respect to the MySQL server actually is the Web server, not the remote program being run by the user who connects to the Web server. To deal with these problems, we changed how *Note `LOAD DATA LOCAL': load-data. is handled as of MySQL 3.23.49 and MySQL 4.0.2 (4.0.13 on Windows): * By default, all MySQL clients and libraries in binary distributions are compiled with the `--enable-local-infile' option, to be compatible with MySQL 3.23.48 and before. * If you build MySQL from source but do not invoke `configure' with the `--enable-local-infile' option, *Note `LOAD DATA LOCAL': load-data. cannot be used by any client unless it is written explicitly to invoke *Note `mysql_options(... MYSQL_OPT_LOCAL_INFILE, 0)': mysql-options. See *Note mysql-options::. * You can disable all *Note `LOAD DATA LOCAL': load-data. statements from the server side by starting *Note `mysqld': mysqld. with the `--local-infile=0' option. * For the *Note `mysql': mysql. command-line client, enable *Note `LOAD DATA LOCAL': load-data. by specifying the `--local-infile[=1]' option, or disable it with the `--local-infile=0' option. For *Note `mysqlimport': mysqlimport, local data file loading is off by default; enable it with the `--local' or `-L' option. In any case, successful use of a local load operation requires that the server permits it. * If you use *Note `LOAD DATA LOCAL': load-data. in Perl scripts or other programs that read the `[client]' group from option files, you can add the `local-infile=1' option to that group. However, to keep this from causing problems for programs that do not understand `local-infile', specify it using the `loose-' prefix: [client] loose-local-infile=1 * If *Note `LOAD DATA LOCAL': load-data. is disabled, either in the server or the client, a client that attempts to issue such a statement receives the following error message: ERROR 1148: The used command is not allowed with this MySQL version  File: manual.info, Node: changing-mysql-user, Prev: load-data-local, Up: security 6.3.6 How to Run MySQL as a Normal User --------------------------------------- On Windows, you can run the server as a Windows service using a normal user account. On Unix, the MySQL server *Note `mysqld': mysqld. can be started and run by any user. However, you should avoid running the server as the Unix `root' user for security reasons. To change *Note `mysqld': mysqld. to run as a normal unprivileged Unix user USER_NAME, you must do the following: 1. Stop the server if it is running (use *Note `mysqladmin shutdown': mysqladmin.). 2. Change the database directories and files so that USER_NAME has privileges to read and write files in them (you might need to do this as the Unix `root' user): shell> chown -R USER_NAME /PATH/TO/MYSQL/DATADIR If you do not do this, the server will not be able to access databases or tables when it runs as USER_NAME. If directories or files within the MySQL data directory are symbolic links, `chown -R' might not follow symbolic links for you. If it does not, you will also need to follow those links and change the directories and files they point to. 3. Start the server as user USER_NAME. Another alternative is to start *Note `mysqld': mysqld. as the Unix `root' user and use the `--user=USER_NAME' option. *Note `mysqld': mysqld. starts up, then switches to run as the Unix user USER_NAME before accepting any connections. 4. To start the server as the given user automatically at system startup time, specify the user name by adding a `user' option to the `[mysqld]' group of the `/etc/my.cnf' option file or the `my.cnf' option file in the server's data directory. For example: [mysqld] user=USER_NAME If your Unix machine itself is not secured, you should assign passwords to the MySQL `root' accounts in the grant tables. Otherwise, any user with a login account on that machine can run the *Note `mysql': mysql. client with a `--user=root' option and perform any operation. (It is a good idea to assign passwords to MySQL accounts in any case, but especially so when other login accounts exist on the server host.) See *Note postinstallation::.  File: manual.info, Node: privilege-system, Next: user-account-management, Prev: security, Up: server-administration 6.4 The MySQL Access Privilege System ===================================== * Menu: * privileges-provided:: Privileges Provided by MySQL * grant-table-structure:: Privilege System Grant Tables * account-names:: Specifying Account Names * connection-access:: Access Control, Stage 1: Connection Verification * request-access:: Access Control, Stage 2: Request Verification * privilege-changes:: When Privilege Changes Take Effect * access-denied:: Causes of Access-Denied Errors The primary function of the MySQL privilege system is to authenticate a user who connects from a given host and to associate that user with privileges on a database such as *Note `SELECT': select, *Note `INSERT': insert, *Note `UPDATE': update, and *Note `DELETE': delete. Additional functionality includes the ability to have anonymous users and to grant privileges for MySQL-specific functions such as *Note `LOAD DATA INFILE': load-data. and administrative operations. There are some things that you cannot do with the MySQL privilege system: * You cannot explicitly specify that a given user should be denied access. That is, you cannot explicitly match a user and then refuse the connection. * You cannot specify that a user has privileges to create or drop tables in a database but not to create or drop the database itself. * A password applies globally to an account. You cannot associate a password with a specific object such as a database, table, or routine. The user interface to the MySQL privilege system consists of SQL statements such as *Note `CREATE USER': create-user, *Note `GRANT': grant, and *Note `REVOKE': revoke. See *Note account-management-sql::. Internally, the server stores privilege information in the grant tables of the `mysql' database (that is, in the database named `mysql'). The MySQL server reads the contents of these tables into memory when it starts and bases access-control decisions on the in-memory copies of the grant tables. The MySQL privilege system ensures that all users may perform only the operations permitted to them. As a user, when you connect to a MySQL server, your identity is determined by _the host from which you connect_ and _the user name you specify_. When you issue requests after connecting, the system grants privileges according to your identity and _what you want to do_. MySQL considers both your host name and user name in identifying you because there is no reason to assume that a given user name belongs to the same person on all hosts. For example, the user `joe' who connects from `office.example.com' need not be the same person as the user `joe' who connects from `home.example.com'. MySQL handles this by enabling you to distinguish users on different hosts that happen to have the same name: You can grant one set of privileges for connections by `joe' from `office.example.com', and a different set of privileges for connections by `joe' from `home.example.com'. To see what privileges a given account has, use the *Note `SHOW GRANTS': show-grants. statement. For example: SHOW GRANTS FOR 'joe'@'office.example.com'; SHOW GRANTS FOR 'joe'@'home.example.com'; MySQL access control involves two stages when you run a client program that connects to the server: *Stage 1:* The server accepts or rejects the connection based on your identity and whether you can verify your identity by supplying the correct password. *Stage 2:* Assuming that you can connect, the server checks each statement you issue to determine whether you have sufficient privileges to perform it. For example, if you try to select rows from a table in a database or drop a table from the database, the server verifies that you have the `SELECT' privilege for the table or the `DROP' privilege for the database. For a more detailed description of what happens during each stage, see *Note connection-access::, and *Note request-access::. If your privileges are changed (either by yourself or someone else) while you are connected, those changes do not necessarily take effect immediately for the next statement that you issue. For details about the conditions under which the server reloads the grant tables, see *Note privilege-changes::. For general security-related advice, see *Note security::. For help in diagnosing privilege-related problems, see *Note access-denied::.  File: manual.info, Node: privileges-provided, Next: grant-table-structure, Prev: privilege-system, Up: privilege-system 6.4.1 Privileges Provided by MySQL ---------------------------------- MySQL provides privileges that apply in different contexts and at different levels of operation: * Administrative privileges enable users to manage operation of the MySQL server. These privileges are global because they are not specific to a particular database. * Database privileges apply to a database and to all objects within it. These privileges can be granted for specific databases, or globally so that they apply to all databases. * Privileges for database objects such as tables, indexes, views, and stored routines can be granted for specific objects within a database, for all objects of a given type within a database (for example, all tables in a database), or globally for all objects of a given type in all databases). Information about account privileges is stored in the `user', `db', `host', `tables_priv', `columns_priv', and `procs_priv' tables in the `mysql' database (see *Note grant-table-structure::). The MySQL server reads the contents of these tables into memory when it starts and reloads them under the circumstances indicated in *Note privilege-changes::. Access-control decisions are based on the in-memory copies of the grant tables. Some releases of MySQL introduce changes to the structure of the grant tables to add new access privileges or features. Whenever you update to a new version of MySQL, you should update your grant tables to make sure that they have the current structure so that you can take advantage of any new capabilities. See *Note mysql-upgrade::. The following table shows the privilege names used at the SQL level in the *Note `GRANT': grant. and *Note `REVOKE': revoke. statements, along with the column name associated with each privilege in the grant tables and the context in which the privilege applies. *Permissible Privileges for `GRANT' and `REVOKE'* Privilege Column Context `CREATE' `Create_priv' databases, tables, or indexes `DROP' `Drop_priv' databases, tables, or views `GRANT OPTION' `Grant_priv' databases, tables, or stored routines `REFERENCES' `References_priv' databases or tables `EVENT' `Event_priv' databases `ALTER' `Alter_priv' tables `DELETE' `Delete_priv' tables `INDEX' `Index_priv' tables `INSERT' `Insert_priv' tables or columns `SELECT' `Select_priv' tables or columns `UPDATE' `Update_priv' tables or columns `CREATE TEMPORARY `Create_tmp_table_priv' tables TABLES' `LOCK TABLES' `Lock_tables_priv' tables `TRIGGER' `Trigger_priv' tables `CREATE VIEW' `Create_view_priv' views `SHOW VIEW' `Show_view_priv' views `ALTER ROUTINE' `Alter_routine_priv' stored routines `CREATE ROUTINE' `Create_routine_priv' stored routines `EXECUTE' `Execute_priv' stored routines `FILE' `File_priv' file access on server host `CREATE USER' `Create_user_priv' server administration `PROCESS' `Process_priv' server administration `RELOAD' `Reload_priv' server administration `REPLICATION CLIENT' `Repl_client_priv' server administration `REPLICATION SLAVE' `Repl_slave_priv' server administration `SHOW DATABASES' `Show_db_priv' server administration `SHUTDOWN' `Shutdown_priv' server administration `SUPER' `Super_priv' server administration `ALL [PRIVILEGES]' server administration `USAGE' server administration The following list provides a general description of each privilege available in MySQL. Particular SQL statements might have more specific privilege requirements than indicated here. If so, the description for the statement in question provides the details. * The `ALL' or `ALL PRIVILEGES' privilege specifier is shorthand. It stands for `all privileges available at a given privilege level' (except `GRANT OPTION'). For example, granting `ALL' at the global or table level grants all global privileges or all table-level privileges. * The `ALTER' privilege enables use of *Note `ALTER TABLE': alter-table. to change the structure of tables. *Note `ALTER TABLE': alter-table. also requires the `CREATE' and `INSERT' privileges. Renaming a table requires `ALTER' and `DROP' on the old table, `ALTER', `CREATE', and `INSERT' on the new table. * The `ALTER ROUTINE' privilege is needed to alter or drop stored routines (procedures and functions). * The `CREATE' privilege enables creation of new databases and tables. * The `CREATE ROUTINE' privilege is needed to create stored routines (procedures and functions). * The `CREATE TEMPORARY TABLES' privilege enables the creation of temporary tables using the *Note `CREATE TEMPORARY TABLE': create-table. statement. However, other operations on a temporary table, such as *Note `INSERT': insert, *Note `UPDATE': update, or *Note `SELECT': select, require additional privileges for those operations for the database containing the temporary table, or for the nontemporary table of the same name. To keep privileges for temporary and nontemporary tables separate, a common workaround for this situation is to create a database dedicated to the use of temporary tables. Then for that database, a user can be granted the `CREATE TEMPORARY TABLES' privilege, along with any other privileges required for temporary table operations done by that user. * The `CREATE USER' privilege enables use of *Note `CREATE USER': create-user, *Note `DROP USER': drop-user, *Note `RENAME USER': rename-user, and *Note `REVOKE ALL PRIVILEGES': revoke. * The `CREATE VIEW' privilege enables use of *Note `CREATE VIEW': create-view. * The `DELETE' privilege enables rows to be deleted from tables in a database. * The `DROP' privilege enables you to drop (remove) existing databases, tables, and views. Beginning with MySQL 5.1.10, the `DROP' privilege is also required to use the statement `ALTER TABLE ... DROP PARTITION' on a partitioned table. Beginning with MySQL 5.1.16, the `DROP' privilege is required for *Note `TRUNCATE TABLE': truncate-table. (before that, *Note `TRUNCATE TABLE': truncate-table. requires the `DELETE' privilege). _If you grant the `DROP' privilege for the `mysql' database to a user, that user can drop the database in which the MySQL access privileges are stored._ * The `EVENT' privilege is required to create, alter, or drop events for the Event Scheduler. This privilege was added in MySQL 5.1.6. * The `EXECUTE' privilege is required to execute stored routines (procedures and functions). * The `FILE' privilege gives you permission to read and write files on the server host using the *Note `LOAD DATA INFILE': load-data. and *Note `SELECT ... INTO OUTFILE': select. statements and the `LOAD_FILE()' function. A user who has the `FILE' privilege can read any file on the server host that is either world-readable or readable by the MySQL server. (This implies the user can read any file in any database directory, because the server can access any of those files.) The `FILE' privilege also enables the user to create new files in any directory where the MySQL server has write access. As a security measure, the server will not overwrite existing files. * The `GRANT OPTION' privilege enables you to give to other users or remove from other users those privileges that you yourself possess. * The `INDEX' privilege enables you to create or drop (remove) indexes. `INDEX' applies to existing tables. If you have the `CREATE' privilege for a table, you can include index definitions in the *Note `CREATE TABLE': create-table. statement. * The `INSERT' privilege enables rows to be inserted into tables in a database. `INSERT' is also required for the *Note `ANALYZE TABLE': analyze-table, *Note `OPTIMIZE TABLE': optimize-table, and *Note `REPAIR TABLE': repair-table. table-maintenance statements. * The `LOCK TABLES' privilege enables the use of explicit *Note `LOCK TABLES': lock-tables. statements to lock tables for which you have the `SELECT' privilege. This includes the use of write locks, which prevents other sessions from reading the locked table. * The `PROCESS' privilege pertains to display of information about the threads executing within the server (that is, information about the statements being executed by sessions). The privilege enables use of *Note `SHOW PROCESSLIST': show-processlist. or *Note `mysqladmin processlist': mysqladmin. to see threads belonging to other accounts; you can always see your own threads. * The `REFERENCES' privilege currently is unused. * The `RELOAD' privilege enables use of the *Note `FLUSH': flush. statement. It also enables *Note `mysqladmin': mysqladmin. commands that are equivalent to *Note `FLUSH': flush. operations: `flush-hosts', `flush-logs', `flush-privileges', `flush-status', `flush-tables', `flush-threads', `refresh', and `reload'. The `reload' command tells the server to reload the grant tables into memory. `flush-privileges' is a synonym for `reload'. The `refresh' command closes and reopens the log files and flushes all tables. The other `flush-XXX' commands perform functions similar to `refresh', but are more specific and may be preferable in some instances. For example, if you want to flush just the log files, `flush-logs' is a better choice than `refresh'. * The `REPLICATION CLIENT' privilege enables the use of *Note `SHOW MASTER STATUS': show-master-status. and *Note `SHOW SLAVE STATUS': show-slave-status. * The `REPLICATION SLAVE' privilege should be granted to accounts that are used by slave servers to connect to the current server as their master. Without this privilege, the slave cannot request updates that have been made to databases on the master server. * The `SELECT' privilege enables you to select rows from tables in a database. *Note `SELECT': select. statements require the `SELECT' privilege only if they actually retrieve rows from a table. Some *Note `SELECT': select. statements do not access tables and can be executed without permission for any database. For example, you can use *Note `SELECT': select. as a simple calculator to evaluate expressions that make no reference to tables: SELECT 1+1; SELECT PI()*2; The `SELECT' privilege is also needed for other statements that read column values. For example, `SELECT' is needed for columns referenced on the right hand side of COL_NAME=EXPR assignment in *Note `UPDATE': update. statements or for columns named in the `WHERE' clause of *Note `DELETE': delete. or *Note `UPDATE': update. statements. * The `SHOW DATABASES' privilege enables the account to see database names by issuing the `SHOW DATABASE' statement. Accounts that do not have this privilege see only databases for which they have some privileges, and cannot use the statement at all if the server was started with the `--skip-show-database' option. Note that _any_ global privilege is a privilege for the database. * The `SHOW VIEW' privilege enables use of *Note `SHOW CREATE VIEW': show-create-view. * The `SHUTDOWN' privilege enables use of the *Note `mysqladmin shutdown': mysqladmin. command. There is no corresponding SQL statement. * The `SUPER' privilege enables an account to use *Note `CHANGE MASTER TO': change-master-to, *Note `KILL': kill. or *Note `mysqladmin kill': mysqladmin. to kill threads belonging to other accounts (you can always kill your own threads), *Note `PURGE BINARY LOGS': purge-binary-logs, configuration changes using *Note `SET GLOBAL': set-option. to modify global system variables, the *Note `mysqladmin debug': mysqladmin. command, enabling or disabling logging, performing updates even if the `read_only' system variable is enabled, starting and stopping replication on slave servers, specification of any account in the `DEFINER' attribute of stored programs and views, and enables you to connect (once) even if the connection limit controlled by the `max_connections' system variable is reached. To create or alter stored functions if binary logging is enabled, you may also need the `SUPER' privilege, as described in *Note stored-programs-logging::. * The `TRIGGER' privilege enables trigger operations. You must have this privilege for a table to create, drop, or execute triggers for that table. This privilege was added in MySQL 5.1.6. (Prior to MySQL 5.1.6, trigger operations required the `SUPER' privilege.) * The `UPDATE' privilege enables rows to be updated in tables in a database. * The `USAGE' privilege specifier stands for `no privileges.' It is used at the global level with *Note `GRANT': grant. to modify account attributes such as resource limits or SSL characteristics without affecting existing account privileges. It is a good idea to grant to an account only those privileges that it needs. You should exercise particular caution in granting the `FILE' and administrative privileges: * The `FILE' privilege can be abused to read into a database table any files that the MySQL server can read on the server host. This includes all world-readable files and files in the server's data directory. The table can then be accessed using *Note `SELECT': select. to transfer its contents to the client host. * The `GRANT OPTION' privilege enables users to give their privileges to other users. Two users that have different privileges and with the `GRANT OPTION' privilege are able to combine privileges. * The `ALTER' privilege may be used to subvert the privilege system by renaming tables. * The `SHUTDOWN' privilege can be abused to deny service to other users entirely by terminating the server. * The `PROCESS' privilege can be used to view the plain text of currently executing statements, including statements that set or change passwords. * The `SUPER' privilege can be used to terminate other sessions or change how the server operates. * Privileges granted for the `mysql' database itself can be used to change passwords and other access privilege information. Passwords are stored encrypted, so a malicious user cannot simply read them to know the plain text password. However, a user with write access to the `user' table `Password' column can change an account's password, and then connect to the MySQL server using that account.  File: manual.info, Node: grant-table-structure, Next: account-names, Prev: privileges-provided, Up: privilege-system 6.4.2 Privilege System Grant Tables ----------------------------------- Normally, you manipulate the contents of the grant tables in the `mysql' database indirectly by using statements such as *Note `GRANT': grant. and *Note `REVOKE': revoke. to set up accounts and control the privileges available to each one. See *Note account-management-sql::. The discussion here describes the underlying structure of the grant tables and how the server uses their contents when interacting with clients. These `mysql' database tables contain grant information: * `user': Contains user accounts, global privileges, and other non-privilege columns. * `db': Contains database-level privileges. * `host': Obsolete. * `tables_priv': Contains table-level privileges. * `columns_priv': Contains column-level privileges. * `procs_priv': Contains stored procedure and function privileges. Other tables in the `mysql' database do not hold grant information and are discussed elsewhere: * `event': Contains information about Event Scheduler events: See *Note events::. * `func': Contains information about user-defined functions: See *Note adding-functions::. * `help_XXX': These tables are used for server-side help: See *Note server-side-help-support::. * `plugin': Contains information about server plugins: See *Note server-plugin-loading::, and *Note plugin-api::. * `proc': Contains information about stored procedures and functions: See *Note stored-routines::. * `servers': Used by the `FEDERATED' storage engine: See *Note federated-create-server::. * `time_zone_XXX': These tables contain time zone information: See *Note time-zone-support::. * Tables with `_log' in their name are used for logging: See *Note server-logs::. Each grant table contains scope columns and privilege columns: * Scope columns determine the scope of each row (entry) in the tables; that is, the context in which the row applies. For example, a `user' table row with `Host' and `User' values of `'thomas.loc.gov'' and `'bob'' would be used for authenticating connections made to the server from the host `thomas.loc.gov' by a client that specifies a user name of `bob'. Similarly, a `db' table row with `Host', `User', and `Db' column values of `'thomas.loc.gov'', `'bob'' and `'reports'' would be used when `bob' connects from the host `thomas.loc.gov' to access the `reports' database. The `tables_priv' and `columns_priv' tables contain scope columns indicating tables or table/column combinations to which each row applies. The `procs_priv' scope columns indicate the stored routine to which each row applies. * Privilege columns indicate which privileges are granted by a table row; that is, what operations can be performed. The server combines the information in the various grant tables to form a complete description of a user's privileges. *Note request-access::, describes the rules that are used to do this. The server uses the grant tables in the following manner: * The `user' table scope columns determine whether to reject or permit incoming connections. For permitted connections, any privileges granted in the `user' table indicate the user's global privileges. Any privilege granted in this table applies to _all_ databases on the server. *Note*: Because any global privilege is considered a privilege for all databases, any global privilege enables a user to see all database names with *Note `SHOW DATABASES': show-databases. or by examining the *Note `SCHEMATA': schemata-table. table of `INFORMATION_SCHEMA'. * The `db' table scope columns determine which users can access which databases from which hosts. The privilege columns determine which operations are permitted. A privilege granted at the database level applies to the database and to all objects in the database, such as tables and stored programs. * The `host' table is used in conjunction with the `db' table when you want a given `db' table row to apply to several hosts. For example, if you want a user to be able to use a database from several hosts in your network, leave the `Host' value empty in the user's `db' table row, then populate the `host' table with a row for each of those hosts. This mechanism is described more detail in *Note request-access::. *Note*: The `host' table must be modified directly with statements such as *Note `INSERT': insert, *Note `UPDATE': update, and *Note `DELETE': delete. It is not affected by statements such as *Note `GRANT': grant. and *Note `REVOKE': revoke. that modify the grant tables indirectly. Most MySQL installations need not use this table at all. * The `tables_priv' and `columns_priv' tables are similar to the `db' table, but are more fine-grained: They apply at the table and column levels rather than at the database level. A privilege granted at the table level applies to the table and to all its columns. A privilege granted at the column level applies only to a specific column. * The `procs_priv' table applies to stored routines. A privilege granted at the routine level applies only to a single routine. The server uses the `user', `db', and `host' tables in the `mysql' database at both the first and second stages of access control (see *Note privilege-system::). The columns in the `user' and `db' tables are shown here. The `host' table is similar to the `db' table but has a specialized use as described in *Note request-access::. *`user' and `db' Table Columns* Table Name `user' `db' *Scope columns* `Host' `Host' `User' `Db' `Password' `User' *Privilege columns* `Select_priv' `Select_priv' `Insert_priv' `Insert_priv' `Update_priv' `Update_priv' `Delete_priv' `Delete_priv' `Index_priv' `Index_priv' `Alter_priv' `Alter_priv' `Create_priv' `Create_priv' `Drop_priv' `Drop_priv' `Grant_priv' `Grant_priv' `Create_view_priv' `Create_view_priv' `Show_view_priv' `Show_view_priv' `Create_routine_priv' `Create_routine_priv' `Alter_routine_priv' `Alter_routine_priv' `Execute_priv' `Execute_priv' `Trigger_priv' `Trigger_priv' `Event_priv' `Event_priv' `Create_tmp_table_priv'`Create_tmp_table_priv' `Lock_tables_priv' `Lock_tables_priv' `References_priv' `References_priv' `Reload_priv' `Shutdown_priv' `Process_priv' `File_priv' `Show_db_priv' `Super_priv' `Repl_slave_priv' `Repl_client_priv' `Create_user_priv' *Security columns* `ssl_type' `ssl_cipher' `x509_issuer' `x509_subject' *Resource control columns* `max_questions' `max_updates' `max_connections' `max_user_connections' The `Event_priv' and `Trigger_priv' columns were added in MySQL 5.1.6. During the second stage of access control, the server performs request verification to make sure that each client has sufficient privileges for each request that it issues. In addition to the `user', `db', and `host' grant tables, the server may also consult the `tables_priv' and `columns_priv' tables for requests that involve tables. The latter tables provide finer privilege control at the table and column levels. They have the columns shown in the following table. *`tables_priv' and `columns_priv' Table Columns* Table Name `tables_priv' `columns_priv' *Scope `Host' `Host' columns* `Db' `Db' `User' `User' `Table_name' `Table_name' `Column_name' *Privilege `Table_priv' `Column_priv' columns* `Column_priv' *Other `Timestamp' `Timestamp' columns* `Grantor' The `Timestamp' and `Grantor' columns currently are unused and are discussed no further here. For verification of requests that involve stored routines, the server may consult the `procs_priv' table, which has the columns shown in the following table. *`procs_priv' Table Columns* Table Name `procs_priv' *Scope `Host' columns* `Db' `User' `Routine_name' `Routine_type' *Privilege `Proc_priv' columns* *Other `Timestamp' columns* `Grantor' The `Routine_type' column is an *Note `ENUM': enum. column with values of `'FUNCTION'' or `'PROCEDURE'' to indicate the type of routine the row refers to. This column enables privileges to be granted separately for a function and a procedure with the same name. The `Timestamp' and `Grantor' columns currently are unused and are discussed no further here. Scope columns in the grant tables contain strings. They are declared as shown here; the default value for each is the empty string. *Grant Table Scope Column Types* Column Name Type `Host' `CHAR(60)' `User' `CHAR(16)' `Password' `CHAR(41)' `Db' `CHAR(64)' `Table_name' `CHAR(64)' `Column_name' `CHAR(64)' `Routine_name' `CHAR(64)' For access-checking purposes, comparisons of `User', `Password', `Db', and `Table_name' values are case sensitive. Comparisons of `Host', `Column_name', and `Routine_name' values are not case sensitive. In the `user', `db', and `host' tables, each privilege is listed in a separate column that is declared as `ENUM('N','Y') DEFAULT 'N''. In other words, each privilege can be disabled or enabled, with the default being disabled. In the `tables_priv', `columns_priv', and `procs_priv' tables, the privilege columns are declared as *Note `SET': set. columns. Values in these columns can contain any combination of the privileges controlled by the table. Only those privileges listed in the column value are enabled. *Set-Type Privilege Column Values* Table Name Column Name Possible Set Elements `tables_priv' `Table_priv' `'Select', 'Insert', 'Update', 'Delete', 'Create', 'Drop', 'Grant', 'References', 'Index', 'Alter', 'Create View', 'Show view', 'Trigger'' `tables_priv' `Column_priv' `'Select', 'Insert', 'Update', 'References'' `columns_priv' `Column_priv' `'Select', 'Insert', 'Update', 'References'' `procs_priv' `Proc_priv' `'Execute', 'Alter Routine', 'Grant'' Administrative privileges (such as `RELOAD' or `SHUTDOWN') are specified only in the `user' table. Administrative operations are operations on the server itself and are not database-specific, so there is no reason to list these privileges in the other grant tables. Consequently, to determine whether you can perform an administrative operation, the server need consult only the `user' table. The `FILE' privilege also is specified only in the `user' table. It is not an administrative privilege as such, but your ability to read or write files on the server host is independent of the database you are accessing. The *Note `mysqld': mysqld. server reads the contents of the grant tables into memory when it starts. You can tell it to reload the tables by issuing a *Note `FLUSH PRIVILEGES': flush. statement or executing a *Note `mysqladmin flush-privileges': mysqladmin. or *Note `mysqladmin reload': mysqladmin. command. Changes to the grant tables take effect as indicated in *Note privilege-changes::. When you modify an account's privileges, it is a good idea to verify that the changes set up privileges the way you want. To check the privileges for a given account, use the *Note `SHOW GRANTS': show-grants. statement (see *Note show-grants::). For example, to determine the privileges that are granted to an account with user name and host name values of `bob' and `pc84.example.com', use this statement: SHOW GRANTS FOR 'bob'@'pc84.example.com';  File: manual.info, Node: account-names, Next: connection-access, Prev: grant-table-structure, Up: privilege-system 6.4.3 Specifying Account Names ------------------------------ MySQL account names consist of a user name and a host name. This enables creation of accounts for users with the same name who can connect from different hosts. This section describes how to write account names, including special values and wildcard rules. In SQL statements such as *Note `CREATE USER': create-user, *Note `GRANT': grant, and *Note `SET PASSWORD': set-password, write account names using the following rules: * Syntax for account names is `'USER_NAME'@'HOST_NAME''. * An account name consisting only of a user name is equivalent to `'USER_NAME'@'%''. For example, `'me'' is equivalent to `'me'@'%''. * The user name and host name need not be quoted if they are legal as unquoted identifiers. Quotes are necessary to specify a USER_NAME string containing special characters (such as ``-''), or a HOST_NAME string containing special characters or wildcard characters (such as ``%''); for example, `'test-user'@'%.com''. * Quote user names and host names as identifiers or as strings, using either backticks (```''), single quotation marks (``'''), or double quotation marks (``"''). * The user name and host name parts, if quoted, must be quoted separately. That is, write `'me'@'localhost'', not `'me@localhost''; the latter is interpreted as `'me@localhost'@'%''. * A reference to the `CURRENT_USER()' (or `CURRENT_USER') function is equivalent to specifying the current user's name and host name literally. MySQL stores account names in grant tables in the `mysql' database using separate columns for the user name and host name parts: * The `user' table contains one row for each account. The `User' and `Host' columns store the user name and host name. This table also indicates which global privileges the account has. * Other grant tables indicate privileges an account has for databases and objects within databases. These tables have `User' and `Host' columns to store the account name. Each row in these tables associates with the account in the `user' table that has the same `User' and `Host' values. For additional detail about grant table structure, see *Note grant-table-structure::. User names and host names have certain special values or wildcard conventions, as described following. A user name is either a nonblank value that literally matches the user name for incoming connection attempts, or a blank value (empty string) that matches any user name. An account with a blank user name is an anonymous user. To specify an anonymous user in SQL statements, use a quoted empty user name part, such as `''@'localhost''. The host name part of an account name can take many forms, and wildcards are permitted: * A host value can be a host name or an IP address. The name `'localhost'' indicates the local host. The IP address `'127.0.0.1'' indicates the loopback interface. * You can use the wildcard characters ``%'' and ``_'' in host values. These have the same meaning as for pattern-matching operations performed with the `LIKE' operator. For example, a host value of `'%'' matches any host name, whereas a value of `'%.mysql.com'' matches any host in the `mysql.com' domain. `'192.168.1.%'' matches any host in the 192.168.1 class C network. Because you can use IP wildcard values in host values (for example, `'192.168.1.%'' to match every host on a subnet), someone could try to exploit this capability by naming a host `192.168.1.somewhere.com'. To foil such attempts, MySQL disallows matching on host names that start with digits and a dot. Thus, if you have a host named something like `1.2.example.com', its name never matches the host part of account names. An IP wildcard value can match only IP addresses, not host names. * For a host value specified as an IP address, you can specify a netmask indicating how many address bits to use for the network number. The syntax is `HOST_IP/NETMASK'. For example: CREATE USER 'david'@'192.58.197.0/255.255.255.0'; This enables `david' to connect from any client host having an IP address CLIENT_IP for which the following condition is true: CLIENT_IP & NETMASK = HOST_IP That is, for the *Note `CREATE USER': create-user. statement just shown: CLIENT_IP & 255.255.255.0 = 192.58.197.0 IP addresses that satisfy this condition and can connect to the MySQL server are those in the range from `192.58.197.0' to `192.58.197.255'. The netmask can only be used to tell the server to use 8, 16, 24, or 32 bits of the address. Examples: * `192.0.0.0/255.0.0.0': Any host on the 192 class A network * `192.168.0.0/255.255.0.0': Any host on the 192.168 class B network * `192.168.1.0/255.255.255.0': Any host on the 192.168.1 class C network * `192.168.1.1': Only the host with this specific IP address The following netmask will not work because it masks 28 bits, and 28 is not a multiple of 8: 192.168.0.1/255.255.255.240  File: manual.info, Node: connection-access, Next: request-access, Prev: account-names, Up: privilege-system 6.4.4 Access Control, Stage 1: Connection Verification ------------------------------------------------------ When you attempt to connect to a MySQL server, the server accepts or rejects the connection based on your identity and whether you can verify your identity by supplying the correct password. If not, the server denies access to you completely. Otherwise, the server accepts the connection, and then enters Stage 2 and waits for requests. Your identity is based on two pieces of information: * The client host from which you connect * Your MySQL user name Identity checking is performed using the three `user' table scope columns (`Host', `User', and `Password'). The server accepts the connection only if the `Host' and `User' columns in some `user' table row match the client host name and user name and the client supplies the password specified in that row. The rules for permissible `Host' and `User' values are given in *Note account-names::. If the `User' column value is nonblank, the user name in an incoming connection must match exactly. If the `User' value is blank, it matches any user name. If the `user' table row that matches an incoming connection has a blank user name, the user is considered to be an anonymous user with no name, not a user with the name that the client actually specified. This means that a blank user name is used for all further access checking for the duration of the connection (that is, during Stage 2). The `Password' column can be blank. This is not a wildcard and does not mean that any password matches. It means that the user must connect without specifying a password. Nonblank `Password' values in the `user' table represent encrypted passwords. MySQL does not store passwords in plaintext form for anyone to see. Rather, the password supplied by a user who is attempting to connect is encrypted (using the `PASSWORD()' function). The encrypted password then is used during the connection process when checking whether the password is correct. (This is done without the encrypted password ever traveling over the connection.) See *Note user-names::. From MySQL's point of view, the encrypted password is the _real_ password, so you should never give anyone access to it. In particular, _do not give nonadministrative users read access to tables in the `mysql' database_. The following table shows how various combinations of `Host' and `User' values in the `user' table apply to incoming connections. `Host' Value `User' Permissible Connections Value `'thomas.loc.gov'' `'fred'' `fred', connecting from `thomas.loc.gov' `'thomas.loc.gov'' `''' Any user, connecting from `thomas.loc.gov' `'%'' `'fred'' `fred', connecting from any host `'%'' `''' Any user, connecting from any host `'%.loc.gov'' `'fred'' `fred', connecting from any host in the `loc.gov' domain `'x.y.%'' `'fred'' `fred', connecting from `x.y.net', `x.y.com', `x.y.edu', and so on; this is probably not useful `'144.155.166.177'' `'fred'' `fred', connecting from the host with IP address `144.155.166.177' `'144.155.166.%'' `'fred'' `fred', connecting from any host in the `144.155.166' class C subnet `'144.155.166.0/255.255.255.0''`'fred'' Same as previous example It is possible for the client host name and user name of an incoming connection to match more than one row in the `user' table. The preceding set of examples demonstrates this: Several of the entries shown match a connection from `thomas.loc.gov' by `fred'. When multiple matches are possible, the server must determine which of them to use. It resolves this issue as follows: * Whenever the server reads the `user' table into memory, it sorts the rows. * When a client attempts to connect, the server looks through the rows in sorted order. * The server uses the first row that matches the client host name and user name. To see how this works, suppose that the `user' table looks like this: +-----------+----------+- | Host | User | ... +-----------+----------+- | % | root | ... | % | jeffrey | ... | localhost | root | ... | localhost | | ... +-----------+----------+- When the server reads the table into memory, it orders the rows with the most-specific `Host' values first. Literal host names and IP addresses are the most specific. (The specificity of a literal IP address is not affected by whether it has a netmask, so `192.168.1.13' and `192.168.1.0/255.255.255.0' are considered equally specific.) The pattern `'%'' means `any host' and is least specific. Rows with the same `Host' value are ordered with the most-specific `User' values first (a blank `User' value means `any user' and is least specific). For the `user' table just shown, the result after sorting looks like this: +-----------+----------+- | Host | User | ... +-----------+----------+- | localhost | root | ... | localhost | | ... | % | jeffrey | ... | % | root | ... +-----------+----------+- When a client attempts to connect, the server looks through the sorted rows and uses the first match found. For a connection from `localhost' by `jeffrey', two of the rows from the table match: the one with `Host' and `User' values of `'localhost'' and `''', and the one with values of `'%'' and `'jeffrey''. The `'localhost'' row appears first in sorted order, so that is the one the server uses. Here is another example. Suppose that the `user' table looks like this: +----------------+----------+- | Host | User | ... +----------------+----------+- | % | jeffrey | ... | thomas.loc.gov | | ... +----------------+----------+- The sorted table looks like this: +----------------+----------+- | Host | User | ... +----------------+----------+- | thomas.loc.gov | | ... | % | jeffrey | ... +----------------+----------+- A connection by `jeffrey' from `thomas.loc.gov' is matched by the first row, whereas a connection by `jeffrey' from any host is matched by the second. *Note*: It is a common misconception to think that, for a given user name, all rows that explicitly name that user are used first when the server attempts to find a match for the connection. This is not true. The preceding example illustrates this, where a connection from `thomas.loc.gov' by `jeffrey' is first matched not by the row containing `'jeffrey'' as the `User' column value, but by the row with no user name. As a result, `jeffrey' is authenticated as an anonymous user, even though he specified a user name when connecting. If you are able to connect to the server, but your privileges are not what you expect, you probably are being authenticated as some other account. To find out what account the server used to authenticate you, use the `CURRENT_USER()' function. (See *Note information-functions::.) It returns a value in `USER_NAME@HOST_NAME' format that indicates the `User' and `Host' values from the matching `user' table row. Suppose that `jeffrey' connects and issues the following query: mysql> SELECT CURRENT_USER(); +----------------+ | CURRENT_USER() | +----------------+ | @localhost | +----------------+ The result shown here indicates that the matching `user' table row had a blank `User' column value. In other words, the server is treating `jeffrey' as an anonymous user. Another way to diagnose authentication problems is to print out the `user' table and sort it by hand to see where the first match is being made.  File: manual.info, Node: request-access, Next: privilege-changes, Prev: connection-access, Up: privilege-system 6.4.5 Access Control, Stage 2: Request Verification --------------------------------------------------- After you establish a connection, the server enters Stage 2 of access control. For each request that you issue through that connection, the server determines what operation you want to perform, then checks whether you have sufficient privileges to do so. This is where the privilege columns in the grant tables come into play. These privileges can come from any of the `user', `db', `host', `tables_priv', `columns_priv', or `procs_priv' tables. (You may find it helpful to refer to *Note grant-table-structure::, which lists the columns present in each of the grant tables.) The `user' table grants privileges that are assigned to you on a global basis and that apply no matter what the default database is. For example, if the `user' table grants you the `DELETE' privilege, you can delete rows from any table in any database on the server host! It is wise to grant privileges in the `user' table only to people who need them, such as database administrators. For other users, you should leave all privileges in the `user' table set to `'N'' and grant privileges at more specific levels only. You can grant privileges for particular databases, tables, columns, or routines. The `db' and `host' tables grant database-specific privileges. Values in the scope columns of these tables can take the following forms: * A blank `User' value in the `db' table matches the anonymous user. A nonblank value matches literally; there are no wildcards in user names. * The wildcard characters ``%'' and ``_'' can be used in the `Host' and `Db' columns of either table. These have the same meaning as for pattern-matching operations performed with the `LIKE' operator. If you want to use either character literally when granting privileges, you must escape it with a backslash. For example, to include the underscore character (``_'') as part of a database name, specify it as ``\_'' in the *Note `GRANT': grant. statement. * A `'%'' `Host' value in the `db' table means `any host.' A blank `Host' value in the `db' table means `consult the `host' table for further information' (a process that is described later in this section). * A `'%'' or blank `Host' value in the `host' table means `any host.' * A `'%'' or blank `Db' value in either table means `any database.' The server reads the `db' and `host' tables into memory and sorts them at the same time that it reads the `user' table. The server sorts the `db' table based on the `Host', `Db', and `User' scope columns, and sorts the `host' table based on the `Host' and `Db' scope columns. As with the `user' table, sorting puts the most-specific values first and least-specific values last, and when the server looks for matching entries, it uses the first match that it finds. The `tables_priv', `columns_priv', and `procs_priv' tables grant table-specific, column-specific, and routine-specific privileges. Values in the scope columns of these tables can take the following forms: * The wildcard characters ``%'' and ``_'' can be used in the `Host' column. These have the same meaning as for pattern-matching operations performed with the `LIKE' operator. * A `'%'' or blank `Host' value means `any host.' * The `Db', `Table_name', `Column_name', and `Routine_name' columns cannot contain wildcards or be blank. The server sorts the `tables_priv', `columns_priv', and `procs_priv' tables based on the `Host', `Db', and `User' columns. This is similar to `db' table sorting, but simpler because only the `Host' column can contain wildcards. The server uses the sorted tables to verify each request that it receives. For requests that require administrative privileges such as `SHUTDOWN' or `RELOAD', the server checks only the `user' table row because that is the only table that specifies administrative privileges. The server grants access if the row permits the requested operation and denies access otherwise. For example, if you want to execute *Note `mysqladmin shutdown': mysqladmin. but your `user' table row does not grant the `SHUTDOWN' privilege to you, the server denies access without even checking the `db' or `host' tables. (They contain no `Shutdown_priv' column, so there is no need to do so.) For database-related requests (*Note `INSERT': insert, *Note `UPDATE': update, and so on), the server first checks the user's global privileges by looking in the `user' table row. If the row permits the requested operation, access is granted. If the global privileges in the `user' table are insufficient, the server determines the user's database-specific privileges by checking the `db' and `host' tables: 1. The server looks in the `db' table for a match on the `Host', `Db', and `User' columns. The `Host' and `User' columns are matched to the connecting user's host name and MySQL user name. The `Db' column is matched to the database that the user wants to access. If there is no row for the `Host' and `User', access is denied. 2. If there is a matching `db' table row and its `Host' column is not blank, that row defines the user's database-specific privileges. 3. If the matching `db' table row's `Host' column is blank, it signifies that the `host' table enumerates which hosts should be permitted access to the database. In this case, a further lookup is done in the `host' table to find a match on the `Host' and `Db' columns. If no `host' table row matches, access is denied. If there is a match, the user's database-specific privileges are computed as the intersection (_not_ the union!) of the privileges in the `db' and `host' table entries; that is, the privileges that are `'Y'' in both entries. (This way you can grant general privileges in the `db' table row and then selectively restrict them on a host-by-host basis using the `host' table entries.) After determining the database-specific privileges granted by the `db' and `host' table entries, the server adds them to the global privileges granted by the `user' table. If the result permits the requested operation, access is granted. Otherwise, the server successively checks the user's table and column privileges in the `tables_priv' and `columns_priv' tables, adds those to the user's privileges, and permits or denies access based on the result. For stored-routine operations, the server uses the `procs_priv' table rather than `tables_priv' and `columns_priv'. Expressed in boolean terms, the preceding description of how a user's privileges are calculated may be summarized like this: global privileges OR (database privileges AND host privileges) OR table privileges OR column privileges OR routine privileges It may not be apparent why, if the global `user' row privileges are initially found to be insufficient for the requested operation, the server adds those privileges to the database, table, and column privileges later. The reason is that a request might require more than one type of privilege. For example, if you execute an *Note `INSERT INTO ... SELECT': insert-select. statement, you need both the `INSERT' and the `SELECT' privileges. Your privileges might be such that the `user' table row grants one privilege and the `db' table row grants the other. In this case, you have the necessary privileges to perform the request, but the server cannot tell that from either table by itself; the privileges granted by the entries in both tables must be combined. The `host' table is not affected by the *Note `GRANT': grant. or *Note `REVOKE': revoke. statements, so it is unused in most MySQL installations. If you modify it directly, you can use it for some specialized purposes, such as to maintain a list of secure servers on the local network that are granted all privileges. You can also use the `host' table to indicate hosts that are _not_ secure. Suppose that you have a machine `public.your.domain' that is located in a public area that you do not consider secure. You can enable access to all hosts on your network except that machine by using `host' table entries like this: +--------------------+----+- | Host | Db | ... +--------------------+----+- | public.your.domain | % | ... (all privileges set to 'N') | %.your.domain | % | ... (all privileges set to 'Y') +--------------------+----+-  File: manual.info, Node: privilege-changes, Next: access-denied, Prev: request-access, Up: privilege-system 6.4.6 When Privilege Changes Take Effect ---------------------------------------- When *Note `mysqld': mysqld. starts, it reads all grant table contents into memory. The in-memory tables become effective for access control at that point. If you modify the grant tables indirectly using account-management statements such as *Note `GRANT': grant, *Note `REVOKE': revoke, *Note `SET PASSWORD': set-password, or *Note `RENAME USER': rename-user, the server notices these changes and loads the grant tables into memory again immediately. If you modify the grant tables directly using statements such as *Note `INSERT': insert, *Note `UPDATE': update, or *Note `DELETE': delete, your changes have no effect on privilege checking until you either restart the server or tell it to reload the tables. If you change the grant tables directly but forget to reload them, your changes have _no effect_ until you restart the server. This may leave you wondering why your changes seem to make no difference! To tell the server to reload the grant tables, perform a flush-privileges operation. This can be done by issuing a *Note `FLUSH PRIVILEGES': flush. statement or by executing a *Note `mysqladmin flush-privileges': mysqladmin. or *Note `mysqladmin reload': mysqladmin. command. A grant table reload affects privileges for each existing client connection as follows: * Table and column privilege changes take effect with the client's next request. * Database privilege changes take effect the next time the client executes a `USE DB_NAME' statement. *Note*: Client applications may cache the database name; thus, this effect may not be visible to them without actually changing to a different database or flushing the privileges. * Global privileges and passwords are unaffected for a connected client. These changes take effect only for subsequent connections. If the server is started with the `--skip-grant-tables' option, it does not read the grant tables or implement any access control. Anyone can connect and do anything, _which is insecure._ To cause a server thus started to read the tables and enable access checking, flush the privileges.  File: manual.info, Node: access-denied, Prev: privilege-changes, Up: privilege-system 6.4.7 Causes of Access-Denied Errors ------------------------------------ If you encounter problems when you try to connect to the MySQL server, the following items describe some courses of action you can take to correct the problem. * Make sure that the server is running. If it is not, clients cannot connect to it. For example, if an attempt to connect to the server fails with a message such as one of those following, one cause might be that the server is not running: shell> mysql ERROR 2003: Can't connect to MySQL server on 'HOST_NAME' (111) shell> mysql ERROR 2002: Can't connect to local MySQL server through socket '/tmp/mysql.sock' (111) * It might be that the server is running, but you are trying to connect using a TCP/IP port, named pipe, or Unix socket file different from the one on which the server is listening. To correct this when you invoke a client program, specify a `--port' option to indicate the proper port number, or a `--socket' option to indicate the proper named pipe or Unix socket file. To find out where the socket file is, you can use this command: shell> netstat -ln | grep mysql * Make sure that the server has not been configured to ignore network connections or (if you are attempting to connect remotely) that it has not been configured to listen only locally on its network interfaces. If the server was started with `--skip-networking', it will not accept TCP/IP connections at all. If the server was started with `--bind-address=127.0.0.1', it will listen for TCP/IP connections only locally on the loopback interface and will not accept remote connections. * Check to make sure that there is no firewall blocking access to MySQL. Your firewall may be configured on the basis of the application being executed, or the port number used by MySQL for communication (3306 by default). Under Linux or Unix, check your IP tables (or similar) configuration to ensure that the port has not been blocked. Under Windows, applications such as ZoneAlarm or the Windows XP personal firewall may need to be configured not to block the MySQL port. * The grant tables must be properly set up so that the server can use them for access control. For some distribution types (such as binary distributions on Windows, or RPM distributions on Linux), the installation process initializes the `mysql' database containing the grant tables. For distributions that do not do this, you must initialize the grant tables manually by running the *Note `mysql_install_db': mysql-install-db. script. For details, see *Note unix-postinstallation::. To determine whether you need to initialize the grant tables, look for a `mysql' directory under the data directory. (The data directory normally is named `data' or `var' and is located under your MySQL installation directory.) Make sure that you have a file named `user.MYD' in the `mysql' database directory. If not, execute the *Note `mysql_install_db': mysql-install-db. script. After running this script and starting the server, test the initial privileges by executing this command: shell> mysql -u root test The server should let you connect without error. * After a fresh installation, you should connect to the server and set up your users and their access permissions: shell> mysql -u root mysql The server should let you connect because the MySQL `root' user has no password initially. That is also a security risk, so setting the password for the `root' accounts is something you should do while you're setting up your other MySQL accounts. For instructions on setting the initial passwords, see *Note default-privileges::. * If you have updated an existing MySQL installation to a newer version, did you run the *Note `mysql_upgrade': mysql-upgrade. script? If not, do so. The structure of the grant tables changes occasionally when new capabilities are added, so after an upgrade you should always make sure that your tables have the current structure. For instructions, see *Note mysql-upgrade::. * If a client program receives the following error message when it tries to connect, it means that the server expects passwords in a newer format than the client is capable of generating: shell> mysql Client does not support authentication protocol requested by server; consider upgrading MySQL client For information on how to deal with this, see *Note password-hashing::, and *Note old-client::. * Remember that client programs use connection parameters specified in option files or environment variables. If a client program seems to be sending incorrect default connection parameters when you have not specified them on the command line, check any applicable option files and your environment. For example, if you get `Access denied' when you run a client without any options, make sure that you have not specified an old password in any of your option files! You can suppress the use of option files by a client program by invoking it with the `--no-defaults' option. For example: shell> mysqladmin --no-defaults -u root version The option files that clients use are listed in *Note option-files::. Environment variables are listed in *Note environment-variables::. * If you get the following error, it means that you are using an incorrect `root' password: shell> mysqladmin -u root -pXXXX ver Access denied for user 'root'@'localhost' (using password: YES) If the preceding error occurs even when you have not specified a password, it means that you have an incorrect password listed in some option file. Try the `--no-defaults' option as described in the previous item. For information on changing passwords, see *Note assigning-passwords::. If you have lost or forgotten the `root' password, see *Note resetting-permissions::. * If you change a password by using *Note `SET PASSWORD': set-password, *Note `INSERT': insert, or *Note `UPDATE': update, you must encrypt the password using the `PASSWORD()' function. If you do not use `PASSWORD()' for these statements, the password will not work. For example, the following statement assigns a password, but fails to encrypt it, so the user is not able to connect afterward: SET PASSWORD FOR 'abe'@'HOST_NAME' = 'eagle'; Instead, set the password like this: SET PASSWORD FOR 'abe'@'HOST_NAME' = PASSWORD('eagle'); The `PASSWORD()' function is unnecessary when you specify a password using the *Note `CREATE USER': create-user. or *Note `GRANT': grant. statements or the *Note `mysqladmin password': mysqladmin. command. Each of those automatically uses `PASSWORD()' to encrypt the password. See *Note assigning-passwords::, and *Note create-user::. * `localhost' is a synonym for your local host name, and is also the default host to which clients try to connect if you specify no host explicitly. To avoid this problem on such systems, you can use a `--host=127.0.0.1' option to name the server host explicitly. This will make a TCP/IP connection to the local *Note `mysqld': mysqld. server. You can also use TCP/IP by specifying a `--host' option that uses the actual host name of the local host. In this case, the host name must be specified in a `user' table row on the server host, even though you are running the client program on the same host as the server. * The `Access denied' error message tells you who you are trying to log in as, the client host from which you are trying to connect, and whether you were using a password. Normally, you should have one row in the `user' table that exactly matches the host name and user name that were given in the error message. For example, if you get an error message that contains `using password: NO', it means that you tried to log in without a password. * If you get an `Access denied' error when trying to connect to the database with `mysql -u USER_NAME', you may have a problem with the `user' table. Check this by executing `mysql -u root mysql' and issuing this SQL statement: SELECT * FROM user; The result should include a row with the `Host' and `User' columns matching your client's host name and your MySQL user name. * If the following error occurs when you try to connect from a host other than the one on which the MySQL server is running, it means that there is no row in the `user' table with a `Host' value that matches the client host: Host ... is not allowed to connect to this MySQL server You can fix this by setting up an account for the combination of client host name and user name that you are using when trying to connect. If you do not know the IP address or host name of the machine from which you are connecting, you should put a row with `'%'' as the `Host' column value in the `user' table. After trying to connect from the client machine, use a `SELECT USER()' query to see how you really did connect. Then change the `'%'' in the `user' table row to the actual host name that shows up in the log. Otherwise, your system is left insecure because it permits connections from any host for the given user name. On Linux, another reason that this error might occur is that you are using a binary MySQL version that is compiled with a different version of the `glibc' library than the one you are using. In this case, you should either upgrade your operating system or `glibc', or download a source distribution of MySQL version and compile it yourself. A source RPM is normally trivial to compile and install, so this is not a big problem. * If you specify a host name when trying to connect, but get an error message where the host name is not shown or is an IP address, it means that the MySQL server got an error when trying to resolve the IP address of the client host to a name: shell> mysqladmin -u root -pXXXX -h SOME_HOSTNAME ver Access denied for user 'root'@'' (using password: YES) If you try to connect as `root' and get the following error, it means that you do not have a row in the `user' table with a `User' column value of `'root'' and that *Note `mysqld': mysqld. cannot resolve the host name for your client: Access denied for user ''@'unknown' These errors indicate a DNS problem. To fix it, execute *Note `mysqladmin flush-hosts': mysqladmin. to reset the internal DNS host name cache. See *Note dns::. Some permanent solutions are: * Determine what is wrong with your DNS server and fix it. * Specify IP addresses rather than host names in the MySQL grant tables. * Put an entry for the client machine name in `/etc/hosts' on Unix or `\windows\hosts' on Windows. * Start *Note `mysqld': mysqld. with the `--skip-name-resolve' option. * Start *Note `mysqld': mysqld. with the `--skip-host-cache' option. * On Unix, if you are running the server and the client on the same machine, connect to `localhost'. Unix connections to `localhost' use a Unix socket file rather than TCP/IP. * On Windows, if you are running the server and the client on the same machine and the server supports named pipe connections, connect to the host name `.' (period). Connections to `.' use a named pipe rather than TCP/IP. * If `mysql -u root test' works but `mysql -h YOUR_HOSTNAME -u root test' results in `Access denied' (where YOUR_HOSTNAME is the actual host name of the local host), you may not have the correct name for your host in the `user' table. A common problem here is that the `Host' value in the `user' table row specifies an unqualified host name, but your system's name resolution routines return a fully qualified domain name (or vice versa). For example, if you have an entry with host `'pluto'' in the `user' table, but your DNS tells MySQL that your host name is `'pluto.example.com'', the entry does not work. Try adding an entry to the `user' table that contains the IP address of your host as the `Host' column value. (Alternatively, you could add an entry to the `user' table with a `Host' value that contains a wildcard; for example, `'pluto.%''. However, use of `Host' values ending with ``%'' is _insecure_ and is _not_ recommended!) * If `mysql -u USER_NAME test' works but `mysql -u USER_NAME OTHER_DB' does not, you have not granted access to the given user for the database named OTHER_DB. * If `mysql -u USER_NAME' works when executed on the server host, but `mysql -h HOST_NAME -u USER_NAME' does not work when executed on a remote client host, you have not enabled access to the server for the given user name from the remote host. * If you cannot figure out why you get `Access denied', remove from the `user' table all entries that have `Host' values containing wildcards (entries that contain `'%'' or `'_'' characters). A very common error is to insert a new entry with `Host'=`'%'' and `User'=`'SOME_USER'', thinking that this enables you to specify `localhost' to connect from the same machine. The reason that this does not work is that the default privileges include an entry with `Host'=`'localhost'' and `User'=`'''. Because that entry has a `Host' value `'localhost'' that is more specific than `'%'', it is used in preference to the new entry when connecting from `localhost'! The correct procedure is to insert a second entry with `Host'=`'localhost'' and `User'=`'SOME_USER'', or to delete the entry with `Host'=`'localhost'' and `User'=`'''. After deleting the entry, remember to issue a *Note `FLUSH PRIVILEGES': flush. statement to reload the grant tables. See also *Note connection-access::. * If you are able to connect to the MySQL server, but get an `Access denied' message whenever you issue a *Note `SELECT ... INTO OUTFILE': select. or *Note `LOAD DATA INFILE': load-data. statement, your entry in the `user' table does not have the `FILE' privilege enabled. * If you change the grant tables directly (for example, by using *Note `INSERT': insert, *Note `UPDATE': update, or *Note `DELETE': delete. statements) and your changes seem to be ignored, remember that you must execute a *Note `FLUSH PRIVILEGES': flush. statement or a *Note `mysqladmin flush-privileges': mysqladmin. command to cause the server to reload the privilege tables. Otherwise, your changes have no effect until the next time the server is restarted. Remember that after you change the `root' password with an *Note `UPDATE': update. statement, you will not need to specify the new password until after you flush the privileges, because the server will not know you've changed the password yet! * If your privileges seem to have changed in the middle of a session, it may be that a MySQL administrator has changed them. Reloading the grant tables affects new client connections, but it also affects existing connections as indicated in *Note privilege-changes::. * If you have access problems with a Perl, PHP, Python, or ODBC program, try to connect to the server with `mysql -u USER_NAME DB_NAME' or `mysql -u USER_NAME -pYOUR_PASS DB_NAME'. If you are able to connect using the *Note `mysql': mysql. client, the problem lies with your program, not with the access privileges. (There is no space between `-p' and the password; you can also use the `--password=YOUR_PASS' syntax to specify the password. If you use the `-p' or `--password' option with no password value, MySQL prompts you for the password.) * For testing purposes, start the *Note `mysqld': mysqld. server with the `--skip-grant-tables' option. Then you can change the MySQL grant tables and use the *Note `mysqlaccess': mysqlaccess. script to check whether your modifications have the desired effect. When you are satisfied with your changes, execute *Note `mysqladmin flush-privileges': mysqladmin. to tell the *Note `mysqld': mysqld. server to reload the privileges. This enables you to begin using the new grant table contents without stopping and restarting the server. * If you get the following error, you may have a problem with the `db' or `host' table: Access to database denied If the entry selected from the `db' table has an empty value in the `Host' column, make sure that there are one or more corresponding entries in the `host' table specifying which hosts the `db' table entry applies to. This problem occurs infrequently because the `host' table is rarely used. * If everything else fails, start the *Note `mysqld': mysqld. server with a debugging option (for example, `--debug=d,general,query'). This prints host and user information about attempted connections, as well as information about each command issued. See MySQL Internals: Porting (http://forge.mysql.com/wiki/MySQL_Internals_Porting). * If you have any other problems with the MySQL grant tables and feel you must post the problem to the mailing list, always provide a dump of the MySQL grant tables. You can dump the tables with the *Note `mysqldump mysql': mysqldump. command. To file a bug report, see the instructions at *Note bug-reports::. In some cases, you may need to restart *Note `mysqld': mysqld. with `--skip-grant-tables' to run *Note `mysqldump': mysqldump.  File: manual.info, Node: user-account-management, Next: multiple-servers, Prev: privilege-system, Up: server-administration 6.5 MySQL User Account Management ================================= * Menu: * user-names:: User Names and Passwords * adding-users:: Adding User Accounts * removing-users:: Removing User Accounts * user-resources:: Setting Account Resource Limits * assigning-passwords:: Assigning Account Passwords * secure-connections:: Using SSL for Secure Connections * windows-and-ssh:: Connecting to MySQL Remotely from Windows with SSH * account-activity-auditing:: Auditing MySQL Account Activity This section describes how to set up accounts for clients of your MySQL server. It discusses the following topics: * The meaning of account names and passwords as used in MySQL and how that compares to names and passwords used by your operating system * How to set up new accounts and remove existing accounts * How to change passwords * Guidelines for using passwords securely * How to use secure connections with SSL See also *Note account-management-sql::, which describes the syntax and use for all user-management SQL statements.  File: manual.info, Node: user-names, Next: adding-users, Prev: user-account-management, Up: user-account-management 6.5.1 User Names and Passwords ------------------------------ MySQL stores accounts in the `user' table of the `mysql' database. An account is defined in terms of a user name and the client host or hosts from which the user can connect to the server. The account may also have a password. For information about account representation in the `user' table, see *Note grant-table-structure::. There are several distinctions between the way user names and passwords are used by MySQL and the way they are used by your operating system: * User names, as used by MySQL for authentication purposes, have nothing to do with user names (login names) as used by Windows or Unix. On Unix, most MySQL clients by default try to log in using the current Unix user name as the MySQL user name, but that is for convenience only. The default can be overridden easily, because client programs permit any user name to be specified with a `-u' or `--user' option. Because this means that anyone can attempt to connect to the server using any user name, you cannot make a database secure in any way unless all MySQL accounts have passwords. Anyone who specifies a user name for an account that has no password is able to connect successfully to the server. * MySQL user names can be up to 16 characters long. Operating system user names, because they are completely unrelated to MySQL user names, may be of a different maximum length. For example, Unix user names typically are limited to eight characters. *Warning*: The limit on MySQL user name length is hard-coded in the MySQL servers and clients, and trying to circumvent it by modifying the definitions of the tables in the `mysql' database _does not work_. You should never alter any of the tables in the `mysql' database in any manner whatsoever except by means of the procedure that is described in *Note mysql-upgrade::. Attempting to redefine MySQL's system tables in any other fashion results in undefined (and unsupported!) behavior. * It is best to use only ASCII characters for user names and passwords. * The server uses MySQL passwords stored in the `user' table to authenticate client connections using MySQL built-in authentication. These passwords have nothing to do with passwords for logging in to your operating system. There is no necessary connection between the `external' password you use to log in to a Windows or Unix machine and the password you use to access the MySQL server on that machine. * MySQL encrypts passwords stored in the `user' table using its own algorithm. This encryption is the same as that implemented by the `PASSWORD()' SQL function but differs from that used during the Unix login process. Unix password encryption is the same as that implemented by the `ENCRYPT()' SQL function. See the descriptions of the `PASSWORD()' and `ENCRYPT()' functions in *Note encryption-functions::. From version 4.1 on, MySQL employs a stronger authentication method that has better password protection during the connection process than in earlier versions. It is secure even if TCP/IP packets are sniffed or the `mysql' database is captured. (In earlier versions, even though passwords are stored in encrypted form in the `user' table, knowledge of the encrypted password value could be used to connect to the MySQL server.) *Note password-hashing::, discusses password encryption further. When you install MySQL, the grant tables are populated with an initial set of accounts. The names and access privileges for these accounts are described in *Note default-privileges::, which also discusses how to assign passwords to them. Thereafter, you normally set up, modify, and remove MySQL accounts using statements such as *Note `CREATE USER': create-user, *Note `GRANT': grant, and *Note `REVOKE': revoke. See *Note account-management-sql::. When you connect to a MySQL server with a command-line client, specify the user name and password as necessary for the account that you want to use: shell> mysql --user=monty --password=PASSWORD DB_NAME If you prefer short options, the command looks like this: shell> mysql -u monty -pPASSWORD DB_NAME There must be _no space_ between the `-p' option and the following password value. If you omit the PASSWORD value following the `--password' or `-p' option on the command line, the client prompts for one. Specifying a password on the command line should be considered insecure. See *Note password-security-user::. You can use an option file to avoid giving the password on the command line. For additional information about specifying user names, passwords, and other connection parameters, see *Note connecting::.  File: manual.info, Node: adding-users, Next: removing-users, Prev: user-names, Up: user-account-management 6.5.2 Adding User Accounts -------------------------- You can create MySQL accounts in two ways: * By using statements intended for creating accounts, such as *Note `CREATE USER': create-user. or *Note `GRANT': grant. These statements cause the server to make appropriate modifications to the grant tables. * By manipulating the MySQL grant tables directly with statements such as *Note `INSERT': insert, *Note `UPDATE': update, or *Note `DELETE': delete. The preferred method is to use account-creation statements because they are more concise and less error-prone than manipulating the grant tables directly. *Note `CREATE USER': create-user. and *Note `GRANT': grant. are described in *Note account-management-sql::. Another option for creating accounts is to use one of several available third-party programs that offer capabilities for MySQL account administration. `phpMyAdmin' is one such program. The following examples show how to use the *Note `mysql': mysql. client program to set up new accounts. These examples assume that privileges have been set up according to the defaults described in *Note default-privileges::. This means that to make changes, you must connect to the MySQL server as the MySQL `root' user, and the `root' account must have the `INSERT' privilege for the `mysql' database and the `RELOAD' administrative privilege. As noted in the examples where appropriate, some of the statements will fail if the server's SQL mode has been set to enable certain restrictions. In particular, strict mode (`STRICT_TRANS_TABLES', `STRICT_ALL_TABLES') and `NO_AUTO_CREATE_USER' will prevent the server from accepting some of the statements. Workarounds are indicated for these cases. For more information about SQL modes and their effect on grant table manipulation, see *Note server-sql-mode::, and *Note grant::. First, use the *Note `mysql': mysql. program to connect to the server as the MySQL `root' user: shell> mysql --user=root mysql If you have assigned a password to the `root' account, you will also need to supply a `--password' or `-p' option, both for this *Note `mysql': mysql. command and for those later in this section. After connecting to the server as `root', you can add new accounts. The following statements use *Note `GRANT': grant. to set up four new accounts: mysql> CREATE USER 'monty'@'localhost' IDENTIFIED BY 'some_pass'; mysql> GRANT ALL PRIVILEGES ON *.* TO 'monty'@'localhost' -> WITH GRANT OPTION; mysql> CREATE USER 'monty'@'%' IDENTIFIED BY 'some_pass'; mysql> GRANT ALL PRIVILEGES ON *.* TO 'monty'@'%' -> WITH GRANT OPTION; mysql> CREATE USER 'admin'@'localhost'; mysql> GRANT RELOAD,PROCESS ON *.* TO 'admin'@'localhost'; mysql> CREATE USER 'dummy'@'localhost'; The accounts created by these statements have the following properties: * Two of the accounts have a user name of `monty' and a password of `some_pass'. Both accounts are superuser accounts with full privileges to do anything. The `'monty'@'localhost'' account can be used only when connecting from the local host. The `'monty'@'%'' account uses the `'%'' wildcard for the host part, so it can be used to connect from any host. It is necessary to have both accounts for `monty' to be able to connect from anywhere as `monty'. Without the `localhost' account, the anonymous-user account for `localhost' that is created by *Note `mysql_install_db': mysql-install-db. would take precedence when `monty' connects from the local host. As a result, `monty' would be treated as an anonymous user. The reason for this is that the anonymous-user account has a more specific `Host' column value than the `'monty'@'%'' account and thus comes earlier in the `user' table sort order. (`user' table sorting is discussed in *Note connection-access::.) * The `'admin'@'localhost'' account has no password. This account can be used only by `admin' to connect from the local host. It is granted the `RELOAD' and `PROCESS' administrative privileges. These privileges enable the `admin' user to execute the *Note `mysqladmin reload': mysqladmin, *Note `mysqladmin refresh': mysqladmin, and *Note `mysqladmin flush-XXX': mysqladmin. commands, as well as *Note `mysqladmin processlist': mysqladmin . No privileges are granted for accessing any databases. You could add such privileges later by issuing other *Note `GRANT': grant. statements. * The `'dummy'@'localhost'' account has no password. This account can be used only to connect from the local host. No privileges are granted. It is assumed that you will grant specific privileges to the account later. The statements that create accounts with no password will fail if the `NO_AUTO_CREATE_USER' SQL mode is enabled. To deal with this, use an `IDENTIFIED BY' clause that specifies a nonempty password. To check the privileges for an account, use *Note `SHOW GRANTS': show-grants.: mysql> SHOW GRANTS FOR 'admin'@'localhost'; +-----------------------------------------------------+ | Grants for admin@localhost | +-----------------------------------------------------+ | GRANT RELOAD, PROCESS ON *.* TO 'admin'@'localhost' | +-----------------------------------------------------+ As an alternative to *Note `CREATE USER': create-user. and *Note `GRANT': grant, you can create the same accounts directly by issuing *Note `INSERT': insert. statements and then telling the server to reload the grant tables using *Note `FLUSH PRIVILEGES': flush.: shell> mysql --user=root mysql mysql> INSERT INTO user -> VALUES('localhost','monty',PASSWORD('some_pass'), -> 'Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y'); mysql> INSERT INTO user -> VALUES('%','monty',PASSWORD('some_pass'), -> 'Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y', -> 'Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y', -> '','','','',0,0,0,0); mysql> INSERT INTO user SET Host='localhost',User='admin', -> Reload_priv='Y', Process_priv='Y'; mysql> INSERT INTO user (Host,User,Password) -> VALUES('localhost','dummy',''); mysql> FLUSH PRIVILEGES; When you create accounts with *Note `INSERT': insert, it is necessary to use *Note `FLUSH PRIVILEGES': flush. to tell the server to reload the grant tables. Otherwise, the changes go unnoticed until you restart the server. With *Note `CREATE USER': create-user, *Note `FLUSH PRIVILEGES': flush. is unnecessary. The reason for using the `PASSWORD()' function with *Note `INSERT': insert. is to encrypt the password. The *Note `CREATE USER': create-user. statement encrypts the password for you, so `PASSWORD()' is unnecessary. The `'Y'' values enable privileges for the accounts. Depending on your MySQL version, you may have to use a different number of `'Y'' values in the first two *Note `INSERT': insert. statements. The *Note `INSERT': insert. statement for the `admin' account employs the more readable extended *Note `INSERT': insert. syntax using `SET'. In the *Note `INSERT': insert. statement for the `dummy' account, only the `Host', `User', and `Password' columns in the `user' table row are assigned values. None of the privilege columns are set explicitly, so MySQL assigns them all the default value of `'N''. This is equivalent to what *Note `CREATE USER': create-user. does. If strict SQL mode is enabled, all columns that have no default value must have a value specified. In this case, *Note `INSERT': insert. statements must explicitly specify values for the `ssl_cipher', `x509_issuer', and `x509_subject' columns. To set up a superuser account, it is necessary only to insert a `user' table row with all privilege columns set to `'Y''. The `user' table privileges are global, so no entries in any of the other grant tables are needed. The next examples create three accounts and give them access to specific databases. Each of them has a user name of `custom' and password of `obscure'. To create the accounts with *Note `CREATE USER': create-user. and *Note `GRANT': grant, use the following statements: shell> mysql --user=root mysql mysql> CREATE USER 'custom'@'localhost' IDENTIFIED BY 'obscure'; mysql> GRANT SELECT,INSERT,UPDATE,DELETE,CREATE,DROP -> ON bankaccount.* -> TO 'custom'@'localhost'; mysql> CREATE USER 'custom'@'host47.example.com' IDENTIFIED BY 'obscure'; mysql> GRANT SELECT,INSERT,UPDATE,DELETE,CREATE,DROP -> ON expenses.* -> TO 'custom'@'host47.example.com'; mysql> CREATE USER 'custom'@'server.domain' IDENTIFIED BY 'obscure'; mysql> GRANT SELECT,INSERT,UPDATE,DELETE,CREATE,DROP -> ON customer.* -> TO 'custom'@'server.domain'; The three accounts can be used as follows: * The first account can access the `bankaccount' database, but only from the local host. * The second account can access the `expenses' database, but only from the host `host47.example.com'. * The third account can access the `customer' database, but only from the host `server.domain'. To set up the `custom' accounts without *Note `GRANT': grant, use *Note `INSERT': insert. statements as follows to modify the grant tables directly: shell> mysql --user=root mysql mysql> INSERT INTO user (Host,User,Password) -> VALUES('localhost','custom',PASSWORD('obscure')); mysql> INSERT INTO user (Host,User,Password) -> VALUES('host47.example.com','custom',PASSWORD('obscure')); mysql> INSERT INTO user (Host,User,Password) -> VALUES('server.domain','custom',PASSWORD('obscure')); mysql> INSERT INTO db -> (Host,Db,User,Select_priv,Insert_priv, -> Update_priv,Delete_priv,Create_priv,Drop_priv) -> VALUES('localhost','bankaccount','custom', -> 'Y','Y','Y','Y','Y','Y'); mysql> INSERT INTO db -> (Host,Db,User,Select_priv,Insert_priv, -> Update_priv,Delete_priv,Create_priv,Drop_priv) -> VALUES('host47.example.com','expenses','custom', -> 'Y','Y','Y','Y','Y','Y'); mysql> INSERT INTO db -> (Host,Db,User,Select_priv,Insert_priv, -> Update_priv,Delete_priv,Create_priv,Drop_priv) -> VALUES('server.domain','customer','custom', -> 'Y','Y','Y','Y','Y','Y'); mysql> FLUSH PRIVILEGES; The first three *Note `INSERT': insert. statements add `user' table entries that permit the user `custom' to connect from the various hosts with the given password, but grant no global privileges (all privileges are set to the default value of `'N''). The next three *Note `INSERT': insert. statements add `db' table entries that grant privileges to `custom' for the `bankaccount', `expenses', and `customer' databases, but only when accessed from the proper hosts. As usual when you modify the grant tables directly, you must tell the server to reload them with *Note `FLUSH PRIVILEGES': flush. so that the privilege changes take effect. To create a user who has access from all machines in a given domain (for example, `mydomain.com'), you can use the ``%'' wildcard character in the host part of the account name: mysql> CREATE USER 'myname'@'%.mydomain.com' IDENTIFIED BY 'mypass'; To do the same thing by modifying the grant tables directly, do this: mysql> INSERT INTO user (Host,User,Password,...) -> VALUES('%.mydomain.com','myname',PASSWORD('mypass'),...); mysql> FLUSH PRIVILEGES;  File: manual.info, Node: removing-users, Next: user-resources, Prev: adding-users, Up: user-account-management 6.5.3 Removing User Accounts ---------------------------- To remove an account, use the *Note `DROP USER': drop-user. statement, which is described in *Note drop-user::.  File: manual.info, Node: user-resources, Next: assigning-passwords, Prev: removing-users, Up: user-account-management 6.5.4 Setting Account Resource Limits ------------------------------------- One means of limiting use of MySQL server resources is to set the global `max_user_connections' system variable to a nonzero value. This limits the number of simultaneous connections that can be made by any given account, but places no limits on what a client can do once connected. In addition, setting `max_user_connections' does not enable management of individual accounts. Both types of control are of interest to many MySQL administrators, particularly those working for Internet Service Providers. In MySQL 5.1, you can limit use of the following server resources for individual accounts: * The number of queries that an account can issue per hour * The number of updates that an account can issue per hour * The number of times an account can connect to the server per hour * The number of simultaneous connections to the server by an account Any statement that a client can issue counts against the query limit (unless its results are served from the query cache). Only statements that modify databases or tables count against the update limit. An `account' in this context corresponds to a row in the `mysql.user' table. That is, a connection is assessed against the `User' and `Host' values in the `user' table row that applies to the connection. For example, an account `'usera'@'%.example.com'' corresponds to a row in the `user' table that has `User' and `Host' values of `usera' and `%.example.com', to permit `usera' to connect from any host in the `example.com' domain. In this case, the server applies resource limits in this row collectively to all connections by `usera' from any host in the `example.com' domain because all such connections use the same account. Before MySQL 5.0.3, an `account' was assessed against the actual host from which a user connects. This older method accounting may be selected by starting the server with the `--old-style-user-limits' option. In this case, if `usera' connects simultaneously from `host1.example.com' and `host2.example.com', the server applies the account resource limits separately to each connection. If `usera' connects again from `host1.example.com', the server applies the limits for that connection together with the existing connection from that host. To set resource limits for an account, use the *Note `GRANT': grant. statement (see *Note grant::). Provide a `WITH' clause that names each resource to be limited. The default value for each limit is zero (no limit). For example, to create a new account that can access the `customer' database, but only in a limited fashion, issue these statements: mysql> CREATE USER 'francis'@'localhost' IDENTIFIED BY 'frank'; mysql> GRANT ALL ON customer.* TO 'francis'@'localhost' -> WITH MAX_QUERIES_PER_HOUR 20 -> MAX_UPDATES_PER_HOUR 10 -> MAX_CONNECTIONS_PER_HOUR 5 -> MAX_USER_CONNECTIONS 2; The limit types need not all be named in the `WITH' clause, but those named can be present in any order. The value for each per-hour limit should be an integer representing a count per hour. For `MAX_USER_CONNECTIONS', the limit is an integer representing the maximum number of simultaneous connections by the account. If this limit is set to zero, the global `max_user_connections' system variable value determines the number of simultaneous connections. If `max_user_connections' is also zero, there is no limit for the account. To modify existing limits for an account, use a *Note `GRANT USAGE': grant. statement at the global level (`ON *.*'). The following statement changes the query limit for `francis' to 100: mysql> GRANT USAGE ON *.* TO 'francis'@'localhost' -> WITH MAX_QUERIES_PER_HOUR 100; The statement modifies only the limit value specified and leaves the account otherwise unchanged. To remove a limit, set its value to zero. For example, to remove the limit on how many times per hour `francis' can connect, use this statement: mysql> GRANT USAGE ON *.* TO 'francis'@'localhost' -> WITH MAX_CONNECTIONS_PER_HOUR 0; As mentioned previously, the simultaneous-connection limit for an account is determined from the `MAX_USER_CONNECTIONS' limit and the `max_user_connections' system variable. Suppose that the global `max_user_connections' value is 10 and three accounts have resource limits specified with *Note `GRANT': grant.: GRANT ... TO 'user1'@'localhost' WITH MAX_USER_CONNECTIONS 0; GRANT ... TO 'user2'@'localhost' WITH MAX_USER_CONNECTIONS 5; GRANT ... TO 'user3'@'localhost' WITH MAX_USER_CONNECTIONS 20; `user1' has a connection limit of 10 (the global `max_user_connections' value) because it has a zero `MAX_USER_CONNECTIONS' limit). `user2' and `user3' have connection limits of 5 and 20, respectively, because they have nonzero `MAX_USER_CONNECTIONS' limits. The server stores resource limits for an account in the `user' table row corresponding to the account. The `max_questions', `max_updates', and `max_connections' columns store the per-hour limits, and the `max_user_connections' column stores the `MAX_USER_CONNECTIONS' limit. (See *Note grant-table-structure::.) If your `user' table does not have these columns, it must be upgraded; see *Note mysql-upgrade::. Resource-use counting takes place when any account has a nonzero limit placed on its use of any of the resources. As the server runs, it counts the number of times each account uses resources. If an account reaches its limit on number of connections within the last hour, further connections for the account are rejected until that hour is up. Similarly, if the account reaches its limit on the number of queries or updates, further queries or updates are rejected until the hour is up. In all such cases, an appropriate error message is issued. Resource counting is done per account, not per client. For example, if your account has a query limit of 50, you cannot increase your limit to 100 by making two simultaneous client connections to the server. Queries issued on both connections are counted together. The current per-hour resource-use counts can be reset globally for all accounts, or individually for a given account: * To reset the current counts to zero for all accounts, issue a *Note `FLUSH USER_RESOURCES': flush. statement. The counts also can be reset by reloading the grant tables (for example, with a *Note `FLUSH PRIVILEGES': flush. statement or a *Note `mysqladmin reload': mysqladmin. command). * The counts for an individual account can be set to zero by re-granting it any of its limits. To do this, use *Note `GRANT USAGE': grant. as described earlier and specify a limit value equal to the value that the account currently has. Counter resets do not affect the `MAX_USER_CONNECTIONS' limit. All counts begin at zero when the server starts; counts are not carried over through a restart. For the `MAX_USER_CONNECTIONS' limit, an edge case can occur if the account currently has open the maximum number of connections permitted to it: A disconnect followed quickly by a connect can result in an error (`ER_TOO_MANY_USER_CONNECTIONS' or `ER_USER_LIMIT_REACHED') if the server has not fully processed the disconnect by the time the connect occurs. When the server finishes disconnect processing, another connection will once more be permitted.  File: manual.info, Node: assigning-passwords, Next: secure-connections, Prev: user-resources, Up: user-account-management 6.5.5 Assigning Account Passwords --------------------------------- Required credentials for clients that connect to the MySQL server can include a password. This section describes how to assign passwords for MySQL accounts. To assign a password when you create a new account with *Note `CREATE USER': create-user, include an `IDENTIFIED BY' clause: mysql> CREATE USER 'jeffrey'@'localhost' -> IDENTIFIED BY 'mypass'; To assign or change a password for an existing account, one way is to issue a *Note `SET PASSWORD': set-password. statement: mysql> SET PASSWORD FOR -> 'jeffrey'@'localhost' = PASSWORD('mypass'); MySQL stores passwords in the `user' table in the `mysql' database. Only users such as `root' that have update access to the `mysql' database can change the password for other users. If you are not connected as an anonymous user, you can change your own password by omitting the `FOR' clause: mysql> SET PASSWORD = PASSWORD('mypass'); You can also use a *Note `GRANT USAGE': grant. statement at the global level (`ON *.*') to assign a password to an account without affecting the account's current privileges: mysql> GRANT USAGE ON *.* TO 'jeffrey'@'localhost' -> IDENTIFIED BY 'mypass'; To assign a password from the command line, use the *Note `mysqladmin': mysqladmin. command: shell> mysqladmin -u USER_NAME -h HOST_NAME password "NEWPWD" The account for which this command sets the password is the one with a `user' table row that matches USER_NAME in the `User' column and the client host _from which you connect_ in the `Host' column. It is preferable to assign passwords using one of the preceding methods, but it is also possible to modify the `user' table directly. In this case, you must also use *Note `FLUSH PRIVILEGES': flush. to cause the server to reread the grant tables. Otherwise, the change remains unnoticed by the server until you restart it. * To establish a password for a new account, provide a value for the `Password' column: mysql> INSERT INTO mysql.user (Host,User,Password) -> VALUES('localhost','jeffrey',PASSWORD('mypass')); mysql> FLUSH PRIVILEGES; * To change the password for an existing account, use *Note `UPDATE': update. to set the `Password' column value: mysql> UPDATE mysql.user SET Password = PASSWORD('bagel') -> WHERE Host = 'localhost' AND User = 'francis'; mysql> FLUSH PRIVILEGES; During authentication when a client connects to the server, MySQL treats the password in the `user' table as an encrypted hash value (the value that `PASSWORD()' would return for the password). When assigning a password to an account, it is important to store an encrypted value, not the plaintext password. Use the following guidelines: * When you assign a password using *Note `CREATE USER': create-user, *Note `GRANT': grant. with an `IDENTIFIED BY' clause, or the *Note `mysqladmin password': mysqladmin. command, they encrypt the password for you. Specify the literal plaintext password: mysql> CREATE USER 'jeffrey'@'localhost' -> IDENTIFIED BY 'mypass'; * For *Note `CREATE USER': create-user. or *Note `GRANT': grant, you can avoid sending the plaintext password if you know the hash value that `PASSWORD()' would return for the password. Specify the hash value preceded by the keyword `PASSWORD': mysql> CREATE USER 'jeffrey'@'localhost' -> IDENTIFIED BY PASSWORD '*90E462C37378CED12064BB3388827D2BA3A9B689'; * When you assign an account a nonempty password using *Note `SET PASSWORD': set-password, *Note `INSERT': insert, or *Note `UPDATE': update, you must use the `PASSWORD()' function to encrypt the password, otherwise the password is stored as plaintext. Suppose that you assign a password like this: mysql> SET PASSWORD FOR -> 'jeffrey'@'localhost' = 'mypass'; The result is that the literal value `'mypass'' is stored as the password in the `user' table, not the encrypted value. When `jeffrey' attempts to connect to the server using this password, the value is encrypted and compared to the value stored in the `user' table. However, the stored value is the literal string `'mypass'', so the comparison fails and the server rejects the connection with an `Access denied' error. In MySQL 5.1, enabling the `read_only' system variable prevents the use of the *Note `SET PASSWORD': set-password. statement by any user not having the `SUPER' privilege. *Note*: `PASSWORD()' encryption differs from Unix password encryption. See *Note user-names::.  File: manual.info, Node: secure-connections, Next: windows-and-ssh, Prev: assigning-passwords, Up: user-account-management 6.5.6 Using SSL for Secure Connections -------------------------------------- * Menu: * secure-basics:: Basic SSL Concepts * secure-using-ssl:: Using SSL Connections * ssl-options:: SSL Command Options * secure-create-certs:: Setting Up SSL Certificates for MySQL MySQL supports secure (encrypted) connections between MySQL clients and the server using the Secure Sockets Layer (SSL) protocol. This section discusses how to use SSL connections. For information on how to require users to use SSL connections, see the discussion of the `REQUIRE' clause of the *Note `GRANT': grant. statement in *Note grant::. The standard configuration of MySQL is intended to be as fast as possible, so encrypted connections are not used by default. Doing so would make the client/server protocol much slower. Encrypting data is a CPU-intensive operation that requires the computer to do additional work and can delay other MySQL tasks. For applications that require the security provided by encrypted connections, the extra computation is warranted. MySQL enables encryption on a per-connection basis. You can choose a normal unencrypted connection or a secure encrypted SSL connection according the requirements of individual applications. Secure connections are based on the OpenSSL API and are available through the MySQL C API. Replication uses the C API, so secure connections can be used between master and slave servers. Another way to connect securely is from within an SSH connection to the MySQL server host. For an example, see *Note windows-and-ssh::.  File: manual.info, Node: secure-basics, Next: secure-using-ssl, Prev: secure-connections, Up: secure-connections 6.5.6.1 Basic SSL Concepts .......................... To understand how MySQL uses SSL, it is necessary to explain some basic SSL and X509 concepts. People who are familiar with these can skip this part of the discussion. By default, MySQL uses unencrypted connections between the client and the server. This means that someone with access to the network could watch all your traffic and look at the data being sent or received. They could even change the data while it is in transit between client and server. To improve security a little, you can compress client/server traffic by using the `--compress' option when invoking client programs. However, this does not foil a determined attacker. When you need to move information over a network in a secure fashion, an unencrypted connection is unacceptable. Encryption is the way to make any kind of data unreadable. In fact, today's practice requires many additional security elements from encryption algorithms. They should resist many kind of known attacks such as changing the order of encrypted messages or replaying data twice. SSL is a protocol that uses different encryption algorithms to ensure that data received over a public network can be trusted. It has mechanisms to detect any data change, loss, or replay. SSL also incorporates algorithms that provide identity verification using the X509 standard. X509 makes it possible to identify someone on the Internet. It is most commonly used in e-commerce applications. In basic terms, there should be some company called a `Certificate Authority' (or CA) that assigns electronic certificates to anyone who needs them. Certificates rely on asymmetric encryption algorithms that have two encryption keys (a public key and a secret key). A certificate owner can show the certificate to another party as proof of identity. A certificate consists of its owner's public key. Any data encrypted with this public key can be decrypted only using the corresponding secret key, which is held by the owner of the certificate. If you need more information about SSL, X509, or encryption, use your favorite Internet search engine to search for the keywords in which you are interested.  File: manual.info, Node: secure-using-ssl, Next: ssl-options, Prev: secure-basics, Up: secure-connections 6.5.6.2 Using SSL Connections ............................. To use SSL connections between the MySQL server and client programs, your system must support either OpenSSL or yaSSL and your version of MySQL must be built with SSL support. To make it easier to use secure connections, MySQL is bundled with yaSSL. (MySQL and yaSSL employ the same licensing model, whereas OpenSSL uses an Apache-style license.) yaSSL support initially was available only for a few platforms, but now it is available on all MySQL platforms supported by Oracle Corporation. To get secure connections to work with MySQL and SSL, you must do the following: 1. If you are not using a binary (precompiled) version of MySQL that has been built with SSL support, and you are going to use OpenSSL rather than the bundled yaSSL library, install OpenSSL if it has not already been installed. We have tested MySQL with OpenSSL 0.9.6. To obtain OpenSSL, visit `http://www.openssl.org'. Building MySQL using OpenSSL requires a shared OpenSSL library, otherwise linker errors occur. Alternatively, build MySQL using yaSSL. 2. If you are not using a binary (precompiled) version of MySQL that has been built with SSL support, configure a MySQL source distribution to use SSL. When you configure MySQL, invoke the `configure' script like this: shell> ./configure --with-ssl That configures the distribution to use the bundled yaSSL library. To use OpenSSL instead, specify the `--with-ssl' option with the path to the directory where the OpenSSL header files and libraries are located: shell> ./configure --with-ssl=PATH *Note*: On some platforms the full determination of the You may also need to explicitly add the SSL library and header directories. You can do this by setting the `LDFLAGS', `CFLAGS', `CPPFLAGS' and `CXXFLAGS' with the full directories. For example: shell> LDFLAGS="-L/usr/local/ssl/lib" CFLAGS="-I/usr/local/ssl/include" \ CPPFLAGS="-I/usr/local/ssl/include" CXXFLAGS="-I/usr/local/ssl/include" \ configure --with-ssl=/usr/local/ssl Before MySQL 5.1.11, you must use the appropriate option to select the SSL library that you want to use. For yaSSL: shell> ./configure --with-yassl For OpenSSL: shell> ./configure --with-openssl Note that yaSSL support on Unix platforms requires that either `/dev/urandom' or `/dev/random' be available to retrieve true random numbers. For additional information (especially regarding yaSSL on Solaris versions prior to 2.8 and HP-UX), see Bug#13164. 3. Make sure that the `user' in the `mysql' database includes the SSL-related columns (beginning with `ssl_' and `x509_'). If your `user' table does not have these columns, it must be upgraded; see *Note mysql-upgrade::. 4. To check whether a server binary is compiled with SSL support, invoke it with the `--ssl' option. An error will occur if the server does not support SSL: shell> mysqld --ssl --help 060525 14:18:52 [ERROR] mysqld: unknown option '--ssl' To check whether a running *Note `mysqld': mysqld. server supports SSL, examine the value of the `have_ssl' system variable (if you have no `have_ssl' variable, check for `have_openssl'): mysql> SHOW VARIABLES LIKE 'have_ssl'; +---------------+-------+ | Variable_name | Value | +---------------+-------+ | have_ssl | YES | +---------------+-------+ If the value is `YES', the server supports SSL connections. If the value is `DISABLED', the server supports SSL connections but was not started with the appropriate `--ssl-XXX' options (described later in this section). To enable SSL connections, the proper SSL-related options must be used (see *Note ssl-options::). To start the MySQL server so that it permits clients to connect using SSL, use the options that identify the key and certificate files the server needs when establishing a secure connection: shell> mysqld --ssl-ca=CA-CERT.PEM \ --ssl-cert=SERVER-CERT.PEM \ --ssl-key=SERVER-KEY.PEM * `--ssl-ca' identifies the Certificate Authority (CA) certificate. * `--ssl-cert' identifies the server public key. This can be sent to the client and authenticated against the CA certificate that it has. * `--ssl-key' identifies the server private key. To establish a secure connection to a MySQL server with SSL support, the options that a client must specify depend on the SSL requirements of the user account that the client uses. (See the discussion of the `REQUIRE' clause in *Note grant::.) If the account has no special SSL requirements or was created using a *Note `GRANT': grant. statement that includes the `REQUIRE SSL' option, a client can connect securely by using just the `--ssl-ca' option: shell> mysql --ssl-ca=CA-CERT.PEM To require that a client certificate also be specified, create the account using the `REQUIRE X509' option. Then the client must also specify the proper client key and certificate files or the server will reject the connection: shell> mysql --ssl-ca=CA-CERT.PEM \ --ssl-cert=CLIENT-CERT.PEM \ --ssl-key=CLIENT-KEY.PEM In other words, the options are similar to those used for the server. Note that the Certificate Authority certificate has to be the same. A client can determine whether the current connection with the server uses SSL by checking the value of the `Ssl_cipher' status variable. The value of `Ssl_cipher' is nonempty if SSL is used, and empty otherwise. For example: mysql> SHOW STATUS LIKE 'Ssl_cipher'; +---------------+--------------------+ | Variable_name | Value | +---------------+--------------------+ | Ssl_cipher | DHE-RSA-AES256-SHA | +---------------+--------------------+ For the *Note `mysql': mysql. client, you can use the `STATUS' or `\s' command and check the `SSL' line: mysql> \s ... SSL: Not in use ... Or: mysql> \s ... SSL: Cipher in use is DHE-RSA-AES256-SHA ... To establish a secure connection from within an application program, use the *Note `mysql_ssl_set()': mysql-ssl-set. C API function to set the appropriate certificate options before calling *Note `mysql_real_connect()': mysql-real-connect. See *Note mysql-ssl-set::. After the connection is established, you can use *Note `mysql_get_ssl_cipher()': mysql-get-ssl-cipher. to determine whether SSL is in use. A non-`NULL' return value indicates a secure connection and names the SSL cipher used for encryption. A `NULL' return value indicates that SSL is not being used. See *Note mysql-get-ssl-cipher::.  File: manual.info, Node: ssl-options, Next: secure-create-certs, Prev: secure-using-ssl, Up: secure-connections 6.5.6.3 SSL Command Options ........................... The following list describes options that are used for specifying the use of SSL, certificate files, and key files. They can be given on the command line or in an option file. These options are not available unless MySQL has been built with SSL support. See *Note secure-using-ssl::. (There are also `--master-ssl*' options that can be used for setting up a secure connection from a slave replication server to a master server; see *Note replication-options::.) *SSL Option/Variable Summary* Name Cmd-Line Option file System Var Status Var Var Scope Dynamic have_openssl Yes Global No have_ssl Yes Global No skip-ssl Yes Yes ssl Yes Yes ssl-ca Yes Yes Global No - _Variable_: Yes Global No ssl_ca ssl-capath Yes Yes Global No - _Variable_: Yes Global No ssl_capath ssl-cert Yes Yes Global No - _Variable_: Yes Global No ssl_cert ssl-cipher Yes Yes Global No - _Variable_: Yes Global No ssl_cipher ssl-key Yes Yes Global No - _Variable_: Yes Global No ssl_key ssl-verify-server-certYes Yes * `--ssl' For the server, this option specifies that the server permits SSL connections. For a client program, it permits the client to connect to the server using SSL. This option is not sufficient in itself to cause an SSL connection to be used. You must also specify the `--ssl-ca' option, and possibly the `--ssl-cert' and `--ssl-key' options. This option is more often used in its opposite form to override any other SSL options and indicate that SSL should _not_ be used. To do this, specify the option as `--skip-ssl' or `--ssl=0'. Note that use of `--ssl' does not _require_ an SSL connection. For example, if the server or client is compiled without SSL support, a normal unencrypted connection is used. The secure way to require use of an SSL connection is to create an account on the server that includes a `REQUIRE SSL' clause in the *Note `GRANT': grant. statement. Then use that account to connect to the server, where both the server and the client have SSL support enabled. The `REQUIRE' clause permits other SSL-related restrictions as well. The description of `REQUIRE' in *Note grant::, provides additional detail about which SSL command options may or must be specified by clients that connect using accounts that are created using the various `REQUIRE' options. * `--ssl-ca=FILE_NAME' The path to a file that contains a list of trusted SSL CAs. * `--ssl-capath=DIRECTORY_NAME' The path to a directory that contains trusted SSL CA certificates in PEM format. * `--ssl-cert=FILE_NAME' The name of the SSL certificate file to use for establishing a secure connection. * `--ssl-cipher=CIPHER_LIST' A list of permissible ciphers to use for SSL encryption. For greatest portability, CIPHER_LIST should be a list of one or more cipher names, separated by colons. Examples: --ssl-cipher=AES128-SHA --ssl-cipher=DHE-RSA-AES256-SHA:AES128-SHA This format is understood both by OpenSSL and yaSSL. OpenSSL supports a more flexible syntax for specifying ciphers, as described in the OpenSSL documentation at `http://www.openssl.org/docs/apps/ciphers.html'. However, this extended syntax will fail if used with a MySQL installation compiled against yaSSL. If no cipher in the list is supported, SSL connections will not work. * `--ssl-key=FILE_NAME' The name of the SSL key file to use for establishing a secure connection. * `--ssl-verify-server-cert' This option is available for client programs only, not the server. It causes the server's Common Name value in the certificate that the server sends to the client to be verified against the host name that the client uses for connecting to the server, and the connection is rejected if there is a mismatch. This feature can be used to prevent man-in-the-middle attacks. Verification is disabled by default. This option was added in MySQL 5.1.11. As of MySQL 5.1.18, if you use SSL when establishing a client connection, you can tell the client not to authenticate the server certificate by specifying neither `--ssl-ca' nor `--ssl-capath'. The server still verifies the client according to any applicable requirements established using *Note `GRANT': grant. statements for the client, and it still uses any `--ssl-ca'/`--ssl-capath' values that were passed to server at startup time.  File: manual.info, Node: secure-create-certs, Prev: ssl-options, Up: secure-connections 6.5.6.4 Setting Up SSL Certificates for MySQL ............................................. This section demonstrates how to set up SSL certificate and key files for use by MySQL servers and clients. The first example shows a simplified procedure such as you might use from the command line. The second shows a script that contains more detail. The first two examples are intended for use on Unix and both use the `openssl' command that is part of OpenSSL. The third example describes how to set up SSL files on Windows. Following the third example, instructions are given for using the files to test SSL connections. You can also use the files as described in *Note secure-using-ssl::. * Example 1: Creating SSL Files from the Command Line on Unix * The following example shows a set of commands to create MySQL server and client certificate and key files. You will need to respond to several prompts by the `openssl' commands. To generate test files, you can press Enter to all prompts. To generate files for production use, you should provide nonempty responses. # Create clean environment shell> rm -rf newcerts shell> mkdir newcerts && cd newcerts # Create CA certificate shell> openssl genrsa 2048 > ca-key.pem shell> openssl req -new -x509 -nodes -days 1000 \ -key ca-key.pem -out ca-cert.pem # Create server certificate shell> openssl req -newkey rsa:2048 -days 1000 \ -nodes -keyout server-key.pem -out server-req.pem shell> openssl x509 -req -in server-req.pem -days 1000 \ -CA ca-cert.pem -CAkey ca-key.pem -set_serial 01 -out server-cert.pem # Create client certificate shell> openssl req -newkey rsa:2048 -days 1000 \ -nodes -keyout client-key.pem -out client-req.pem shell> openssl x509 -req -in client-req.pem -days 1000 \ -CA ca-cert.pem -CAkey ca-key.pem -set_serial 01 -out client-cert.pem * Example 2: Creating SSL Files Using a Script on Unix * Here is an example script that shows how to set up SSL certificates for MySQL: DIR=`pwd`/openssl PRIV=$DIR/private mkdir $DIR $PRIV $DIR/newcerts cp /usr/share/ssl/openssl.cnf $DIR replace ./demoCA $DIR -- $DIR/openssl.cnf # Create necessary files: $database, $serial and $new_certs_dir # directory (optional) touch $DIR/index.txt echo "01" > $DIR/serial # # Generation of Certificate Authority(CA) # openssl req -new -x509 -keyout $PRIV/cakey.pem -out $DIR/ca-cert.pem \ -days 3600 -config $DIR/openssl.cnf # Sample output: # Using configuration from /home/monty/openssl/openssl.cnf # Generating a 1024 bit RSA private key # ................++++++ # .........++++++ # writing new private key to '/home/monty/openssl/private/cakey.pem' # Enter PEM pass phrase: # Verifying password - Enter PEM pass phrase: # ----- # You are about to be asked to enter information that will be # incorporated into your certificate request. # What you are about to enter is what is called a Distinguished Name # or a DN. # There are quite a few fields but you can leave some blank # For some fields there will be a default value, # If you enter '.', the field will be left blank. # ----- # Country Name (2 letter code) [AU]:FI # State or Province Name (full name) [Some-State]:. # Locality Name (eg, city) []: # Organization Name (eg, company) [Internet Widgits Pty Ltd]:MySQL AB # Organizational Unit Name (eg, section) []: # Common Name (eg, YOUR name) []:MySQL admin # Email Address []: # # Create server request and key # openssl req -new -keyout $DIR/server-key.pem -out \ $DIR/server-req.pem -days 3600 -config $DIR/openssl.cnf # Sample output: # Using configuration from /home/monty/openssl/openssl.cnf # Generating a 1024 bit RSA private key # ..++++++ # ..........++++++ # writing new private key to '/home/monty/openssl/server-key.pem' # Enter PEM pass phrase: # Verifying password - Enter PEM pass phrase: # ----- # You are about to be asked to enter information that will be # incorporated into your certificate request. # What you are about to enter is what is called a Distinguished Name # or a DN. # There are quite a few fields but you can leave some blank # For some fields there will be a default value, # If you enter '.', the field will be left blank. # ----- # Country Name (2 letter code) [AU]:FI # State or Province Name (full name) [Some-State]:. # Locality Name (eg, city) []: # Organization Name (eg, company) [Internet Widgits Pty Ltd]:MySQL AB # Organizational Unit Name (eg, section) []: # Common Name (eg, YOUR name) []:MySQL server # Email Address []: # # Please enter the following 'extra' attributes # to be sent with your certificate request # A challenge password []: # An optional company name []: # # Remove the passphrase from the key # openssl rsa -in $DIR/server-key.pem -out $DIR/server-key.pem # # Sign server cert # openssl ca -policy policy_anything -out $DIR/server-cert.pem \ -config $DIR/openssl.cnf -infiles $DIR/server-req.pem # Sample output: # Using configuration from /home/monty/openssl/openssl.cnf # Enter PEM pass phrase: # Check that the request matches the signature # Signature ok # The Subjects Distinguished Name is as follows # countryName :PRINTABLE:'FI' # organizationName :PRINTABLE:'MySQL AB' # commonName :PRINTABLE:'MySQL admin' # Certificate is to be certified until Sep 13 14:22:46 2003 GMT # (365 days) # Sign the certificate? [y/n]:y # # # 1 out of 1 certificate requests certified, commit? [y/n]y # Write out database with 1 new entries # Data Base Updated # # Create client request and key # openssl req -new -keyout $DIR/client-key.pem -out \ $DIR/client-req.pem -days 3600 -config $DIR/openssl.cnf # Sample output: # Using configuration from /home/monty/openssl/openssl.cnf # Generating a 1024 bit RSA private key # .....................................++++++ # .............................................++++++ # writing new private key to '/home/monty/openssl/client-key.pem' # Enter PEM pass phrase: # Verifying password - Enter PEM pass phrase: # ----- # You are about to be asked to enter information that will be # incorporated into your certificate request. # What you are about to enter is what is called a Distinguished Name # or a DN. # There are quite a few fields but you can leave some blank # For some fields there will be a default value, # If you enter '.', the field will be left blank. # ----- # Country Name (2 letter code) [AU]:FI # State or Province Name (full name) [Some-State]:. # Locality Name (eg, city) []: # Organization Name (eg, company) [Internet Widgits Pty Ltd]:MySQL AB # Organizational Unit Name (eg, section) []: # Common Name (eg, YOUR name) []:MySQL user # Email Address []: # # Please enter the following 'extra' attributes # to be sent with your certificate request # A challenge password []: # An optional company name []: # # Remove the passphrase from the key # openssl rsa -in $DIR/client-key.pem -out $DIR/client-key.pem # # Sign client cert # openssl ca -policy policy_anything -out $DIR/client-cert.pem \ -config $DIR/openssl.cnf -infiles $DIR/client-req.pem # Sample output: # Using configuration from /home/monty/openssl/openssl.cnf # Enter PEM pass phrase: # Check that the request matches the signature # Signature ok # The Subjects Distinguished Name is as follows # countryName :PRINTABLE:'FI' # organizationName :PRINTABLE:'MySQL AB' # commonName :PRINTABLE:'MySQL user' # Certificate is to be certified until Sep 13 16:45:17 2003 GMT # (365 days) # Sign the certificate? [y/n]:y # # # 1 out of 1 certificate requests certified, commit? [y/n]y # Write out database with 1 new entries # Data Base Updated # # Create a my.cnf file that you can use to test the certificates # cnf="" cnf="$cnf [client]" cnf="$cnf ssl-ca=$DIR/ca-cert.pem" cnf="$cnf ssl-cert=$DIR/client-cert.pem" cnf="$cnf ssl-key=$DIR/client-key.pem" cnf="$cnf [mysqld]" cnf="$cnf ssl-ca=$DIR/ca-cert.pem" cnf="$cnf ssl-cert=$DIR/server-cert.pem" cnf="$cnf ssl-key=$DIR/server-key.pem" echo $cnf | replace " " ' ' > $DIR/my.cnf * Example 3: Creating SSL Files on Windows * Download OpenSSL for Windows. An overview of available packages can be seen here: `http://www.slproweb.com/products/Win32OpenSSL.html' Choose the Win32 OpenSSL Light or Win64 OpenSSL Light package, depending on your architecture (32-bit or 64-bit). The default installation location will be `C:\OpenSSL-Win32' or `C:\OpenSSL-Win64', depending on which package you downloaded. The following instructions assume a default location of `C:\OpenSSL-Win32'. Modify this as necessary if you are using the 64-bit package. if a message occurs during setup indicating `'...critical component is missing: Microsoft Visual C++ 2008 Redistributables'', cancel the setup and download one of the following packages as well, again depending on your architecture (32-bit or 64-bit): * Visual C++ 2008 Redistributables (x86), available at: `http://www.microsoft.com/downloads/details.aspx?FamilyID=9b2da534-3e03-4391-8a4d-074b9f2bc1bf' * Visual C++ 2008 Redistributables (x64), available at: `http://www.microsoft.com/downloads/details.aspx?familyid=BD2A6171-E2D6-4230-B809-9A8D7548C1B6' After installing the additional package, restart the OpenSSL setup. During installation, leave the default `C:\OpenSSL-Win32' as the install path, and also leave the default option `'Copy OpenSSL DLL files to the Windows system directory'' selected. When the installation has finished, add `C:\OpenSSL-Win32\bin' to the Windows System Path variable of your server: 1. On the Windows desktop, right-click the `My Computer' icon, and select `Properties'. 2. Select the `Advanced' tab from the `System Properties' menu that appears, and click the `Environment Variables' button. 3. Under `System Variables', select `Path', then click the `Edit' button. The `Edit System Variable' dialogue should appear. 4. Add `';C:\OpenSSL-Win32\bin'' to the end (notice the semicolon). 5. Press OK 3 times. 6. Check that OpenSSL was correctly integrated into the Path variable by opening a new command console (`Start>Run>cmd.exe') and verifying that OpenSSL is available: Microsoft Windows [Version ...] Copyright (c) 2006 Microsoft Corporation. All rights reserved. C:\Windows\system32>cd \ C:\>openssl OpenSSL> exit <<< If you see the OpenSSL prompt, installation was successful. C:\> Depending on your version of Windows, the preceding instructions might be slightly different. After OpenSSL has been installed, use instructions similar to those from from Example 1 (shown earlier in this section), with the following changes: * Change the following Unix commands: # Create clean environment shell> rm -rf newcerts shell> mkdir newcerts && cd newcerts On Windows, use these commands instead: # Create clean environment shell> md c:\newcerts shell> cd c:\newcerts * When a `'\'' character is shown at the end of a command line, this `'\'' character must be removed and the command lines entered all on a single line. * Testing SSL Connections * To test SSL connections, start the server as follows, where `$DIR' is the path name to the directory where the sample `my.cnf' option file (or `my.ini' on Windows) is located: shell> mysqld --defaults-file=$DIR/my.cnf & Then invoke a client program using the same option file: shell> mysql --defaults-file=$DIR/my.cnf If you have a MySQL source distribution, you can also test your setup by modifying the preceding `my.cnf' file to refer to the demonstration certificate and key files in the `mysql-test/std_data' directory of the distribution.  File: manual.info, Node: windows-and-ssh, Next: account-activity-auditing, Prev: secure-connections, Up: user-account-management 6.5.7 Connecting to MySQL Remotely from Windows with SSH -------------------------------------------------------- This section describes how to get a secure connection to a remote MySQL server with SSH. The information was provided by David Carlson . 1. Install an SSH client on your Windows machine. As a user, the best nonfree one I have found is from `SecureCRT' from `http://www.vandyke.com/'. Another option is `f-secure' from `http://www.f-secure.com/'. You can also find some free ones on `Google' at `http://directory.google.com/Top/Computers/Internet/Protocols/SSH/Clients/Windows/'. 2. Start your Windows SSH client. Set `Host_Name = YOURMYSQLSERVER_URL_OR_IP'. Set `userid=YOUR_USERID' to log in to your server. This `userid' value might not be the same as the user name of your MySQL account. 3. Set up port forwarding. Either do a remote forward (Set `local_port: 3306', `remote_host: YOURMYSQLSERVERNAME_OR_IP', `remote_port: 3306' ) or a local forward (Set `port: 3306', `host: localhost', `remote port: 3306'). 4. Save everything, otherwise you will have to redo it the next time. 5. Log in to your server with the SSH session you just created. 6. On your Windows machine, start some ODBC application (such as Access). 7. Create a new file in Windows and link to MySQL using the ODBC driver the same way you normally do, except type in `localhost' for the MySQL host server, not YOURMYSQLSERVERNAME. At this point, you should have an ODBC connection to MySQL, encrypted using SSH.  File: manual.info, Node: account-activity-auditing, Prev: windows-and-ssh, Up: user-account-management 6.5.8 Auditing MySQL Account Activity ------------------------------------- Applications can use the following guidelines to perform auditing that ties database activity to MySQL accounts. MySQL accounts correspond to rows in the `mysql.user' table. When a client connects successfully, the server authenticates the client to a particular row in this table. The `User' and `Host' column values in this row uniquely identify the account and correspond to the `'USER_NAME'@'HOST_NAME'' format in which account names are written in SQL statements. The account used to authenticate a client determines which privileges the client has. Normally, the `CURRENT_USER()' function can be invoked to determine which account this is for the client user. Its value is constructed from the `User' and `Host' columns of the `user' table row for the account. However, there are circumstances under which the `CURRENT_USER()' value corresponds not to the client user but to a different account. This occurs in contexts when privilege checking is not based the client's account: * Stored routines (procedures and functions) defined with the `SQL SECURITY DEFINER' characteristic * Views defined with the `SQL SECURITY DEFINER' characteristic (as of MySQL 5.1.12) * Triggers and events In those contexts, privilege checking is done against the `DEFINER' account and `CURRENT_USER()' refers to that account, not to the account for the client who invoked the stored routine or view or who caused the trigger to activate. To determine the invoking user, you can call the `USER()' function, which returns a value indicating the actual user name provided by the client and the host from which the client connected. However, this value does not necessarily correspond directly to an account in the `user' table, because the `USER()' value never contains wildcards, whereas account values (as returned by `CURRENT_USER()') may contain user name and host name wildcards. For example, a blank user name matches any user, so an account of `''@'localhost'' enables clients to connect as an anonymous user from the local host with any user name. If this case, if a client connects as `user1' from the local host, `USER()' and `CURRENT_USER()' return different values: mysql> SELECT USER(), CURRENT_USER(); +-----------------+----------------+ | USER() | CURRENT_USER() | +-----------------+----------------+ | user1@localhost | @localhost | +-----------------+----------------+ The host name part of an account can contain wildcards, too. If the host name contains a `'%'' or `'_'' pattern character or uses netmask notation, the account can be used for clients connecting from multiple hosts and the `CURRENT_USER()' value will not indicate which one. For example, the account `'user2'@'%.example.com'' can be used by `user2' to connect from any host in the `example.com' domain. If `user2' connects from `remote.example.com', `USER()' and `CURRENT_USER()' return different values: mysql> SELECT USER(), CURRENT_USER(); +--------------------------+---------------------+ | USER() | CURRENT_USER() | +--------------------------+---------------------+ | user2@remote.example.com | user2@%.example.com | +--------------------------+---------------------+ If an application must invoke `USER()' for user auditing (for example, if it does auditing from within triggers) but must also be able to associate the `USER()' value with an account in the `user' table, it is necessary to avoid accounts that contain wildcards in the `User' or `Host' column. Specifically, do not permit `User' to be empty (which creates an anonymous-user account), and do not permit pattern characters or netmask notation in `Host' values. All accounts must have a nonempty `User' value and literal `Host' value. With respect to the previous examples, the `''@'localhost'' and `'user2'@'%.example.com'' accounts should be changed not to use wildcards: RENAME USER ''@'localhost' TO 'user1'@'localhost'; RENAME USER 'user2'@'%.example.com' TO 'user2'@'remote.example.com'; If `user2' must be able to connect from several hosts in the `example.com' domain, there should be a separate account for each host. To extract the user name or host name part from a `CURRENT_USER()' or `USER()' value, use the `SUBSTRING()' function: mysql> SELECT SUBSTRING_INDEX(CURRENT_USER(),'@',1); +---------------------------------------+ | SUBSTRING_INDEX(CURRENT_USER(),'@',1) | +---------------------------------------+ | user1 | +---------------------------------------+ mysql> SELECT SUBSTRING_INDEX(CURRENT_USER(),'@',-1); +----------------------------------------+ | SUBSTRING_INDEX(CURRENT_USER(),'@',-1) | +----------------------------------------+ | localhost | +----------------------------------------+  File: manual.info, Node: multiple-servers, Prev: user-account-management, Up: server-administration 6.6 Running Multiple MySQL Instances on One Machine =================================================== * Menu: * multiple-data-directories:: Setting Up Multiple Data Directories * multiple-windows-servers:: Running Multiple MySQL Instances on Windows * multiple-unix-servers:: Running Multiple MySQL Instances on Unix * multiple-server-clients:: Using Client Programs in a Multiple-Server Environment In some cases, you might want to run multiple instances of MySQL on a single machine. You might want to test a new MySQL release while leaving an existing production setup undisturbed. Or you might want to give different users access to different *Note `mysqld': mysqld. servers that they manage themselves. (For example, you might be an Internet Service Provider that wants to provide independent MySQL installations for different customers.) It is possible to use a different MySQL server binary per instance, or use the same binary for multiple instances, or any combination of the two approaches. For example, you might run a server from MySQL 5.0 and one from MySQL 5.1, to see how different versions handle a given workload. Or you might run multiple instances of the current production version, each managing a different set of databases. Whether or not you use distinct server binaries, each instance that you run must be configured with unique values for several operating parameters. This eliminates the potential for conflict between instances. Parameters can be set on the command line, in option files, or by setting environment variables. See *Note program-options::. To see the values used by a given instance, connect to it and execute a *Note `SHOW VARIABLES': show-variables. statement. The primary resource managed by a MySQL instance is the data directory. Each instance should use a different data directory, the location of which is specified using the `--datadir=PATH' option. For methods of configuring each instance with its own data directory, and warnings about the dangers of failing to do so, see *Note multiple-data-directories::. In addition to using different data directories, several other options must have different values for each server instance: * `--port=PORT_NUM' `--port' controls the port number for TCP/IP connections. Alternatively, if the host has multiple network addresses, you can use `--bind-address' to cause each server to listen to a different address. * `--socket=PATH' `--socket' controls the Unix socket file path on Unix or the named pipe name on Windows. On Windows, it is necessary to specify distinct pipe names only for those servers configured to permit named-pipe connections. * `--shared-memory-base-name=NAME' This option is used only on Windows. It designates the shared-memory name used by a Windows server to permit clients to connect using shared memory. It is necessary to specify distinct shared-memory names only for those servers configured to permit shared-memory connections. * `--pid-file=FILE_NAME' This option indicates the path name of the file in which the server writes its process ID. If you use the following log file options, their values must differ for each server: * `--general_log_file=FILE_NAME' * `--log-bin[=FILE_NAME]' * `--slow_query_log_file=FILE_NAME' * `--log-error[=FILE_NAME]' For further discussion of log file options, see *Note server-logs::. To achieve better performance, you can specify the following option differently for each server, to spread the load between several physical disks: * `--tmpdir=PATH' Having different temporary directories also makes it easier to determine which MySQL server created any given temporary file. If you have multiple MySQL installations in different locations, you can specify the base directory for each installation with the `--basedir=PATH' option. This causes each instance to automatically use a different data directory, log files, and PID file because the default for each of those parameters is relative to the base directory. In that case, the only other options you need to specify are the `--socket' and `--port' options. Suppose that you install different versions of MySQL using `tar' file binary distributions. These install in different locations, so you can start the server for each installation using the command `bin/mysqld_safe' under its corresponding base directory. *Note `mysqld_safe': mysqld-safe. determines the proper `--basedir' option to pass to *Note `mysqld': mysqld, and you need specify only the `--socket' and `--port' options to *Note `mysqld_safe': mysqld-safe. As discussed in the following sections, it is possible to start additional servers by specifying appropriate command options or by setting environment variables. However, if you need to run multiple servers on a more permanent basis, it is more convenient to use option files to specify for each server those option values that must be unique to it. The `--defaults-file' option is useful for this purpose.  File: manual.info, Node: multiple-data-directories, Next: multiple-windows-servers, Prev: multiple-servers, Up: multiple-servers 6.6.1 Setting Up Multiple Data Directories ------------------------------------------ Each MySQL Instance on a machine should have its own data directory. The location is specified using the `--datadir=PATH' option. There are different methods of setting up a data directory for a new instance: * Create a new data directory * Copy an existing data directory The following discussion provides more detail about each method. *Warning*: Normally, you should never have two servers that update data in the same databases. This may lead to unpleasant surprises if your operating system does not support fault-free system locking. If (despite this warning) you run multiple servers using the same data directory and they have logging enabled, you must use the appropriate options to specify log file names that are unique to each server. Otherwise, the servers try to log to the same files. Even when the preceding precautions are observed, this kind of setup works only with `MyISAM' and `MERGE' tables, and not with any of the other storage engines. Also, this warning against sharing a data directory among servers always applies in an NFS environment. Permitting multiple MySQL servers to access a common data directory over NFS is a _very bad idea_. The primary problem is that NFS is the speed bottleneck. It is not meant for such use. Another risk with NFS is that you must devise a way to ensure that two or more servers do not interfere with each other. Usually NFS file locking is handled by the `lockd' daemon, but at the moment there is no platform that performs locking 100% reliably in every situation. * Create a New Data Directory * With this method, the data directory will be in the same state as when you first install MySQL. It will have the default set of MySQL accounts and no user data. On Unix, initialize the data directory by running *Note `mysql_install_db': mysql-install-db. See *Note unix-postinstallation::. On Windows, the data directory is included in MySQL distributions. If you obtain a distribution in Windows Zip archive format, you can unpack it into a temporary location, then copy the `data' directory from this location to where you are setting up the new instance. * Copy an Existing Data Directory * With this method, any MySQL accounts or user data present in the data directory are carried over to the new data directory. 1. Stop the existing MySQL instance using the data directory. This must be a clean shutdown so that the instance flushes any pending changes to disk. 2. Copy the data directory to the location where the new data directory should be. 3. Copy the `my.cnf' or `my.ini' option file used by the existing instance. This serves as a basis for the new instance. 4. Modify the new option file so that any pathnames referring to the original data directory refer to the new data directory. Also, modify any other options that must be unique per instance, such as the TCP/IP port number and the log files. For a list of parameters that must be unique per instance, see *Note multiple-servers::. 5. Start the new instance, telling it to use the new option file.  File: manual.info, Node: multiple-windows-servers, Next: multiple-unix-servers, Prev: multiple-data-directories, Up: multiple-servers 6.6.2 Running Multiple MySQL Instances on Windows ------------------------------------------------- * Menu: * multiple-windows-command-line-servers:: Starting Multiple MySQL Instances at the Windows Command Line * multiple-windows-services:: Starting Multiple MySQL Instances as Windows Services You can run multiple servers on Windows by starting them manually from the command line, each with appropriate operating parameters, or by installing several servers as Windows services and running them that way. General instructions for running MySQL from the command line or as a service are given in *Note windows-installation::. The following sections describe how to start each server with different values for those options that must be unique per server, such as the data directory. These options are listed in *Note multiple-servers::.  File: manual.info, Node: multiple-windows-command-line-servers, Next: multiple-windows-services, Prev: multiple-windows-servers, Up: multiple-windows-servers 6.6.2.1 Starting Multiple MySQL Instances at the Windows Command Line ..................................................................... The procedure for starting a single MySQL server manually from the command line is described in *Note windows-start-command-line::. To start multiple servers this way, you can specify the appropriate options on the command line or in an option file. It is more convenient to place the options in an option file, but it is necessary to make sure that each server gets its own set of options. To do this, create an option file for each server and tell the server the file name with a `--defaults-file' option when you run it. Suppose that you want to run *Note `mysqld': mysqld. on port 3307 with a data directory of `C:\mydata1', and *Note `mysqld-debug': mysqld. on port 3308 with a data directory of `C:\mydata2'. Use this procedure: 1. Make sure that each data directory exists, including its own copy of the `mysql' database that contains the grant tables. 2. Create two option files. For example, create one file named `C:\my-opts1.cnf' that looks like this: [mysqld] datadir = C:/mydata1 port = 3307 Create a second file named `C:\my-opts2.cnf' that looks like this: [mysqld] datadir = C:/mydata2 port = 3308 3. Use the `--defaults-file' option to start each server with its own option file: C:\> C:\mysql\bin\mysqld --defaults-file=C:\my-opts1.cnf C:\> C:\mysql\bin\mysqld-debug --defaults-file=C:\my-opts2.cnf Each server starts in the foreground (no new prompt appears until the server exits later), so you will need to issue those two commands in separate console windows. To shut down the servers, connect to each using the appropriate port number: C:\> C:\mysql\bin\mysqladmin --port=3307 shutdown C:\> C:\mysql\bin\mysqladmin --port=3308 shutdown Servers configured as just described permit clients to connect over TCP/IP. If your version of Windows supports named pipes and you also want to permit named-pipe connections, use the *Note `mysqld-nt': mysqld. (MySQL 5.1.20 and earlier), *Note `mysqld': mysqld. (MySQL 5.1.21 and later) or *Note `mysqld-debug': mysqld. server and specify options that enable the named pipe and specify its name. Each server that supports named-pipe connections must use a unique pipe name. For example, the `C:\my-opts1.cnf' file might be written like this: [mysqld] datadir = C:/mydata1 port = 3307 enable-named-pipe socket = mypipe1 Modify `C:\my-opts2.cnf' similarly for use by the second server. Then start the servers as described previously. A similar procedure applies for servers that you want to permit shared-memory connections. Enable such connections with the `--shared-memory' option and specify a unique shared-memory name for each server with the `--shared-memory-base-name' option.  File: manual.info, Node: multiple-windows-services, Prev: multiple-windows-command-line-servers, Up: multiple-windows-servers 6.6.2.2 Starting Multiple MySQL Instances as Windows Services ............................................................. On Windows, a MySQL server can run as a Windows service. The procedures for installing, controlling, and removing a single MySQL service are described in *Note windows-start-service::. To set up multiple MySQL services, you must make sure that each instance uses a different service name in addition to the other parameters that must be unique per instance. For the following instructions, suppose that you want to run the *Note `mysqld': mysqld. server from two different versions of MySQL that are installed at `C:\mysql-5.0.92' and `C:\mysql-5.1.59', respectively. (This might be the case if you are running 5.0.92 as your production server, but also want to conduct tests using 5.1.59.) To install MySQL as a Windows service, use the `--install' or `--install-manual' option. For information about these options, see *Note windows-start-service::. Based on the preceding information, you have several ways to set up multiple services. The following instructions describe some examples. Before trying any of them, shut down and remove any existing MySQL services. * *Approach 1:* Specify the options for all services in one of the standard option files. To do this, use a different service name for each server. Suppose that you want to run the 5.0.92 *Note `mysqld': mysqld. using the service name of `mysqld1' and the 5.1.59 *Note `mysqld': mysqld. using the service name `mysqld2'. In this case, you can use the `[mysqld1]' group for 5.0.92 and the `[mysqld2]' group for 5.1.59. For example, you can set up `C:\my.cnf' like this: # options for mysqld1 service [mysqld1] basedir = C:/mysql-5.0.92 port = 3307 enable-named-pipe socket = mypipe1 # options for mysqld2 service [mysqld2] basedir = C:/mysql-5.1.59 port = 3308 enable-named-pipe socket = mypipe2 Install the services as follows, using the full server path names to ensure that Windows registers the correct executable program for each service: C:\> C:\mysql-5.0.92\bin\mysqld --install mysqld1 C:\> C:\mysql-5.1.59\bin\mysqld --install mysqld2 To start the services, use the services manager, or use `NET START' with the appropriate service names: C:\> NET START mysqld1 C:\> NET START mysqld2 To stop the services, use the services manager, or use `NET STOP' with the appropriate service names: C:\> NET STOP mysqld1 C:\> NET STOP mysqld2 * *Approach 2:* Specify options for each server in separate files and use `--defaults-file' when you install the services to tell each server what file to use. In this case, each file should list options using a `[mysqld]' group. With this approach, to specify options for the 5.0.92 *Note `mysqld-nt': mysqld, create a file `C:\my-opts1.cnf' that looks like this: [mysqld] basedir = C:/mysql-5.0.92 port = 3307 enable-named-pipe socket = mypipe1 For the 5.1.59 *Note `mysqld': mysqld, create a file `C:\my-opts2.cnf' that looks like this: [mysqld] basedir = C:/mysql-5.1.59 port = 3308 enable-named-pipe socket = mypipe2 Install the services as follows (enter each command on a single line): C:\> C:\mysql-5.0.92\bin\mysqld --install mysqld1 --defaults-file=C:\my-opts1.cnf C:\> C:\mysql-5.1.59\bin\mysqld --install mysqld2 --defaults-file=C:\my-opts2.cnf When you install a MySQL server as a service and use a `--defaults-file' option, the service name must precede the option. After installing the services, start and stop them the same way as in the preceding example. To remove multiple services, use *Note `mysqld --remove': mysqld. for each one, specifying a service name following the `--remove' option. If the service name is the default (`MySQL'), you can omit it.  File: manual.info, Node: multiple-unix-servers, Next: multiple-server-clients, Prev: multiple-windows-servers, Up: multiple-servers 6.6.3 Running Multiple MySQL Instances on Unix ---------------------------------------------- One way is to run multiple MySQL instances on Unix is to compile different servers with different default TCP/IP ports and Unix socket files so that each one listens on different network interfaces. Compiling in different base directories for each installation also results automatically in a separate, compiled-in data directory, log file, and PID file location for each server. Assume that an existing 5.0 server is configured for the default TCP/IP port number (3306) and Unix socket file (`/tmp/mysql.sock'). To configure a new 5.1.59 server to have different operating parameters, use a `configure' command something like this: shell> ./configure --with-tcp-port=PORT_NUMBER \ --with-unix-socket-path=FILE_NAME \ --prefix=/usr/local/mysql-5.1.59 Here, PORT_NUMBER and FILE_NAME must be different from the default TCP/IP port number and Unix socket file path name, and the `--prefix' value should specify an installation directory different from the one under which the existing MySQL installation is located. If you have a MySQL server listening on a given port number, you can use the following command to find out what operating parameters it is using for several important configurable variables, including the base directory and Unix socket file name: shell> mysqladmin --host=HOST_NAME --port=PORT_NUMBER variables With the information displayed by that command, you can tell what option values _not_ to use when configuring an additional server. If you specify `localhost' as the host name, *Note `mysqladmin': mysqladmin. defaults to using a Unix socket file connection rather than TCP/IP. To explicitly specify the connection protocol, use the `--protocol={TCP|SOCKET|PIPE|MEMORY}' option. You need not compile a new MySQL server just to start with a different Unix socket file and TCP/IP port number. It is also possible to use the same server binary and start each invocation of it with different parameter values at runtime. One way to do so is by using command-line options: shell> mysqld_safe --socket=FILE_NAME --port=PORT_NUMBER To start a second server, provide different `--socket' and `--port' option values, and pass a `--datadir=PATH' option to *Note `mysqld_safe': mysqld-safe. so that the server uses a different data directory. Alternatively, put the options for each server in a different option file, then start each server using a `--defaults-file' option that specifies the path to the appropriate option file. For example, if the option files for two server instances are named `/usr/local/mysql/my.cnf' and `/usr/local/mysql/my.cnf2', start the servers like this: command: shell> mysqld_safe --defaults-file=/usr/local/mysql/my.cnf shell> mysqld_safe --defaults-file=/usr/local/mysql/my.cnf2 Another way to achieve a similar effect is to use environment variables to set the Unix socket file name and TCP/IP port number: shell> MYSQL_UNIX_PORT=/tmp/mysqld-new.sock shell> MYSQL_TCP_PORT=3307 shell> export MYSQL_UNIX_PORT MYSQL_TCP_PORT shell> mysql_install_db --user=mysql shell> mysqld_safe --datadir=/path/to/datadir & This is a quick way of starting a second server to use for testing. The nice thing about this method is that the environment variable settings apply to any client programs that you invoke from the same shell. Thus, connections for those clients are automatically directed to the second server. *Note environment-variables::, includes a list of other environment variables you can use to affect MySQL programs. On Unix, the *Note `mysqld_multi': mysqld-multi. script provides another way to start multiple servers. See *Note mysqld-multi::.  File: manual.info, Node: multiple-server-clients, Prev: multiple-unix-servers, Up: multiple-servers 6.6.4 Using Client Programs in a Multiple-Server Environment ------------------------------------------------------------ To connect with a client program to a MySQL server that is listening to different network interfaces from those compiled into your client, you can use one of the following methods: * Start the client with `--host=HOST_NAME' `--port=PORT_NUMBER' to connect using TCP/IP to a remote server, with `--host=127.0.0.1' `--port=PORT_NUMBER' to connect using TCP/IP to a local server, or with `--host=localhost' `--socket=FILE_NAME' to connect to a local server using a Unix socket file or a Windows named pipe. * Start the client with `--protocol=TCP' to connect using TCP/IP, `--protocol=SOCKET' to connect using a Unix socket file, `--protocol=PIPE' to connect using a named pipe, or `--protocol=MEMORY' to connect using shared memory. For TCP/IP connections, you may also need to specify `--host' and `--port' options. For the other types of connections, you may need to specify a `--socket' option to specify a Unix socket file or Windows named-pipe name, or a `--shared-memory-base-name' option to specify the shared-memory name. Shared-memory connections are supported only on Windows. * On Unix, set the `MYSQL_UNIX_PORT' and `MYSQL_TCP_PORT' environment variables to point to the Unix socket file and TCP/IP port number before you start your clients. If you normally use a specific socket file or port number, you can place commands to set these environment variables in your `.login' file so that they apply each time you log in. See *Note environment-variables::. * Specify the default Unix socket file and TCP/IP port number in the `[client]' group of an option file. For example, you can use `C:\my.cnf' on Windows, or the `.my.cnf' file in your home directory on Unix. See *Note option-files::. * In a C program, you can specify the socket file or port number arguments in the *Note `mysql_real_connect()': mysql-real-connect. call. You can also have the program read option files by calling *Note `mysql_options()': mysql-options. See *Note c-api-functions::. * If you are using the Perl `DBD::mysql' module, you can read options from MySQL option files. For example: $dsn = "DBI:mysql:test;mysql_read_default_group=client;" . "mysql_read_default_file=/usr/local/mysql/data/my.cnf"; $dbh = DBI->connect($dsn, $user, $password); See *Note apis-perl::. Other programming interfaces may provide similar capabilities for reading option files.  File: manual.info, Node: backup-and-recovery, Next: optimization, Prev: server-administration, Up: Top 7 Backup and Recovery ********************* * Menu: * backup-types:: Backup and Recovery Types * backup-methods:: Database Backup Methods * backup-strategy-example:: Example Backup and Recovery Strategy * using-mysqldump:: Using `mysqldump' for Backups * point-in-time-recovery:: Point-in-Time (Incremental) Recovery Using the Binary Log * myisam-table-maintenance:: `MyISAM' Table Maintenance and Crash Recovery It is important to back up your databases so that you can recover your data and be up and running again in case problems occur, such as system crashes, hardware failures, or users deleting data by mistake. Backups are also essential as a safeguard before upgrading a MySQL installation, and they can be used to transfer a MySQL installation to another system or to set up replication slave servers. MySQL offers a variety of backup strategies from which you can choose the methods that best suit the requirements for your installation. This chapter discusses several backup and recovery topics with which you should be familiar: * Types of backups: Logical versus physical, full versus incremental, and so forth. * Methods for creating backups. * Recovery methods, including point-in-time recovery. * Backup scheduling, compression, and encryption. * Table maintenance, to enable recovery of corrupt tables. * Additional Resources * Resources related to backup or to maintaining data availability include the following: * Customers of MySQL Enterprise Edition can use the MySQL Enterprise Backup product for backups. For an overview of the MySQL Enterprise Backup product, see *Note mysql-enterprise-backup::. * A forum dedicated to backup issues is available at `http://forums.mysql.com/list.php?93'. * Details for *Note `mysqldump': mysqldump, *Note `mysqlhotcopy': mysqlhotcopy, and other MySQL backup programs can be found in *Note programs::. * The syntax of the SQL statements described here is given in *Note sql-syntax::. * For additional information about `InnoDB' backup procedures, see *Note innodb-backup::. * Replication enables you to maintain identical data on multiple servers. This has several benefits, such as enabling client query load to be distributed over servers, availability of data even if a given server is taken offline or fails, and the ability to make backups with no impact on the master by using a slave server. See *Note replication::. * MySQL Cluster provides a high-availability, high-redundancy version of MySQL adapted for the distributed computing environment. See *Note mysql-cluster::. For information specifically about MySQL Cluster backup, see *Note mysql-cluster-backup::. * Distributed Replicated Block Device (DRBD) is another high-availability solution. It works by replicating a block device from a primary server to a secondary server at the block level. See *Note ha-overview::  File: manual.info, Node: backup-types, Next: backup-methods, Prev: backup-and-recovery, Up: backup-and-recovery 7.1 Backup and Recovery Types ============================= This section describes the characteristics of different types of backups. * Physical (Raw) Versus Logical Backups * Physical backups consist of raw copies of the directories and files that store database contents. This type of backup is suitable for large, important databases that need to be recovered quickly when problems occur. Logical backups save information represented as logical database structure (*Note `CREATE DATABASE': create-database, *Note `CREATE TABLE': create-table. statements) and content (*Note `INSERT': insert. statements or delimited-text files). This type of backup is suitable for smaller amounts of data where you might edit the data values or table structure, or recreate the data on a different machine architecture. Logical backup methods have these characteristics: * The backup is done by querying the MySQL server to obtain database structure and content information. * Backup is slower than physical methods because the server must access database information and convert it to logical format. If the output is written on the client side, the server must also send it to the backup program. * Output is larger than for physical backup, particularly when saved in text format. * Backup and restore granularity is available at the server level (all databases), database level (all tables in a particular database), or table level. This is true regardless of storage engine. * The backup does not include log or configuration files, or other database-related files that are not part of databases. * Backups stored in logical format are machine independent and highly portable. * Logical backups are performed with the MySQL server running. The server is not taken offline. * Logical backup tools include the *Note `mysqldump': mysqldump. program and the *Note `SELECT ... INTO OUTFILE': select. statement. These work for any storage engine, even `MEMORY'. * To restore logical backups, SQL-format dump files can be processed using the *Note `mysql': mysql. client. To load delimited-text files, use the *Note `LOAD DATA INFILE': load-data. statement or the *Note `mysqlimport': mysqlimport. client. Physical backup methods have these characteristics: * The backup consists of exact copies of database directories and files. Typically this is a copy of all or part of the MySQL data directory. Data from `MEMORY' tables cannot be backed up this way because their contents are not stored on disk. * Physical backup methods are faster than logical because they involve only file copying without conversion. * Output is more compact than for logical backup. * Backup and restore granularity ranges from the level of the entire data directory down to the level of individual files. This may or may not provide for table-level granularity, depending on storage engine. (Each `MyISAM' table corresponds uniquely to a set of files, but an `InnoDB' table shares file storage with other `InnoDB' tables.) * In addition to databases, the backup can include any related files such as log or configuration files. * Backups are portable only to other machines that have identical or similar hardware characteristics. * Backups can be performed while the MySQL server is not running. If the server is running, it is necessary to perform appropriate locking so that the server does not change database contents during the backup. * Physical backup tools include file system-level commands (such as `cp', `scp', `tar', `rsync'), *Note `mysqlhotcopy': mysqlhotcopy. for `MyISAM' tables, `ibbackup' for `InnoDB' tables, or `START BACKUP' for *Note `NDB': mysql-cluster. tables. * For restore, files copied at the file system level or with *Note `mysqlhotcopy': mysqlhotcopy. can be copied back to their original locations with file system commands; `ibbackup' restores `InnoDB' tables, and *Note `ndb_restore': mysql-cluster-programs-ndb-restore. restores *Note `NDB': mysql-cluster. tables. *Online Versus Offline Backups* Online backups take place while the MySQL server is running so that the database information can be obtained from the server. Offline backups take place while the server is stopped. This distinction can also be described as `hot' versus `cold' backups; a `warm' backup is one where the server remains running but locked against modifying data while you access database files externally. Online backup methods have these characteristics: * The backup is less intrusive to other clients, which can connect to the MySQL server during the backup and may be able to access data depending on what operations they need to perform. * Care must be taken to impose appropriate locking so that data modifications do not take place that would compromise backup integrity. The MySQL Enterprise Backup product does such locking automatically. Offline backup methods have these characteristics: * Clients can be affected adversely because the server is unavailable during backup. For that reason, such backups are often taken from a replication slave server that can be taken offline without harming availability. * The backup procedure is simpler because there is no possibility of interference from client activity. A similar distinction between online and offline applies for recovery operations, and similar characteristics apply. However, it is more likely that clients will be affected for online recovery than for online backup because recovery requires stronger locking. During backup, clients might be able to read data while it is being backed up. Recovery modifies data and does not just read it, so clients must be prevented from accessing data while it is being restored. * Local Versus Remote Backups * A local backup is performed on the same host where the MySQL server runs, whereas a remote backup is done from a different host. For some types of backups, the backup can be initiated from a remote host even if the output is written locally on the server. host. * *Note `mysqldump': mysqldump. can connect to local or remote servers. For SQL output (`CREATE' and *Note `INSERT': insert. statements), local or remote dumps can be done and generate output on the client. For delimited-text output (with the `--tab' option), data files are created on the server host. * *Note `mysqlhotcopy': mysqlhotcopy. performs only local backups: It connects to the server to lock it against data modifications and then copies local table files. * *Note `SELECT ... INTO OUTFILE': select. can be initiated from a local or remote client host, but the output file is created on the server host. * Physical backup methods typically are initiated locally on the MySQL server host so that the server can be taken offline, although the destination for copied files might be remote. * Snapshot Backups * Some file system implementations enable `snapshots' to be taken. These provide logical copies of the file system at a given point in time, without requiring a physical copy of the entire file system. (For example, the implementation may use copy-on-write techniques so that only parts of the file system modified after the snapshot time need be copied.) MySQL itself does not provide the capability for taking file system snapshots. It is available through third-party solutions such as Veritas, LVM, or ZFS. * Full Versus Incremental Backups * A full backup includes all data managed by a MySQL server at a given point in time. An incremental backup consists of the changes made to the data during a given time span (from one point in time to another). MySQL has different ways to perform full backups, such as those described earlier in this section. Incremental backups are made possible by enabling the server's binary log, which the server uses to record data changes. * Full Versus Point-in-Time (Incremental) Recovery * A full recovery restores all data from a full backup. This restores the server instance to the state that it had when the backup was made. If that state is not sufficiently current, a full recovery can be followed by recovery of incremental backups made since the full backup, to bring the server to a more up-to-date state. Incremental recovery is recovery of changes made during a given time span. This is also called point-in-time recovery because it makes a server's state current up to a given time. Point-in-time recovery is based on the binary log and typically follows a full recovery from the backup files that restores the server to its state when the backup was made. Then the data changes written in the binary log files are applied as incremental recovery to redo data modifications and bring the server up to the desired point in time. * Table Maintenance * Data integrity can be compromised if tables become corrupt. For *Note `InnoDB': innodb-storage-engine. tables, this is not a typical issue. For programs to check *Note `MyISAM': myisam-storage-engine. tables and repair them if problems are found, see *Note myisam-table-maintenance::. * Backup Scheduling, Compression, and Encryption * Backup scheduling is valuable for automating backup procedures. Compression of backup output reduces space requirements, and encryption of the output provides better security against unauthorized access of backed-up data. MySQL itself does not provide these capabilities. The MySQL Enterprise Backup product can compress `InnoDB' backups, and compression or encryption of backup output can be achieved using file system utilities. Other third-party solutions may be available.  File: manual.info, Node: backup-methods, Next: backup-strategy-example, Prev: backup-types, Up: backup-and-recovery 7.2 Database Backup Methods =========================== This section summarizes some general methods for making backups. * Making a Hot Backup with MySQL Enterprise Backup * Customers of MySQL Enterprise Edition can use the MySQL Enterprise Backup (http://dev.mysql.com/doc/innodb-plugin/1.0/en/glossary.html#glos_mysql_enterprise_backup) product to do physical (http://dev.mysql.com/doc/innodb-plugin/1.0/en/glossary.html#glos_physical) backups of entire instances or selected databases, tables, or both. This product includes features for incremental (http://dev.mysql.com/doc/innodb-plugin/1.0/en/glossary.html#glos_incremental_backup) and compressed (http://dev.mysql.com/doc/innodb-plugin/1.0/en/glossary.html#glos_compressed_backup) backups. Backing up the physical database files makes restore much faster than logical techniques such as the `mysqldump' command. `InnoDB' tables are copied using a hot backup (http://dev.mysql.com/doc/innodb-plugin/1.0/en/glossary.html#glos_hot_backup) mechanism. (Ideally, the `InnoDB' tables should represent a substantial majority of the data.) Tables from other storage engines are copied using a warm backup (http://dev.mysql.com/doc/innodb-plugin/1.0/en/glossary.html#glos_warm_backup) mechanism. For an overview of the MySQL Enterprise Backup product, see *Note mysql-enterprise-backup::. * Making Backups by Copying Table Files * For storage engines that represent each table using its own files, tables can be backed up by copying those files. For example, `MyISAM' tables are stored as files, so it is easy to do a backup by copying files (`*.frm', `*.MYD', and `*.MYI' files). To get a consistent backup, stop the server or lock and flush the relevant tables: LOCK TABLES TBL_LIST READ; FLUSH TABLES TBL_LIST; You need only a read lock; this enables other clients to continue to query the tables while you are making a copy of the files in the database directory. The *Note `FLUSH TABLES': flush. statement is needed to ensure that the all active index pages are written to disk before you start the backup. See *Note lock-tables::, and *Note flush::. You can also create a binary backup simply by copying all table files, as long as the server isn't updating anything. The *Note `mysqlhotcopy': mysqlhotcopy. script uses this method. (But note that table file copying methods do not work if your database contains `InnoDB' tables. *Note `mysqlhotcopy': mysqlhotcopy. does not work for `InnoDB' tables because `InnoDB' does not necessarily store table contents in database directories. Also, even if the server is not actively updating data, `InnoDB' may still have modified data cached in memory and not flushed to disk. * Making Delimited-Text File Backups * To create a text file containing a table's data, you can use `SELECT * INTO OUTFILE 'FILE_NAME' FROM TBL_NAME'. The file is created on the MySQL server host, not the client host. For this statement, the output file cannot already exist because permitting files to be overwritten constitutes a security risk. See *Note select::. This method works for any kind of data file, but saves only table data, not the table structure. Another way to create text data files (along with files containing *Note `CREATE TABLE': create-table. statements for the backed up tables) is to use *Note `mysqldump': mysqldump. with the `--tab' option. See *Note mysqldump-delimited-text::. To reload a delimited-text data file, use *Note `LOAD DATA INFILE': load-data. or *Note `mysqlimport': mysqlimport. * Making Backups with *Note `mysqldump': mysqldump. or *Note `mysqlhotcopy': mysqlhotcopy. * The *Note `mysqldump': mysqldump. program and the *Note `mysqlhotcopy': mysqlhotcopy. script can make backups. *Note `mysqldump': mysqldump. is more general because it can back up all kinds of tables. *Note `mysqlhotcopy': mysqlhotcopy. works only with some storage engines. (See *Note using-mysqldump::, and *Note mysqlhotcopy::.) For `InnoDB' tables, it is possible to perform an online backup that takes no locks on tables using the `--single-transaction' option to *Note `mysqldump': mysqldump. See *Note backup-policy::. * Making Incremental Backups by Enabling the Binary Log * MySQL supports incremental backups: You must start the server with the `--log-bin' option to enable binary logging; see *Note binary-log::. The binary log files provide you with the information you need to replicate changes to the database that are made subsequent to the point at which you performed a backup. At the moment you want to make an incremental backup (containing all changes that happened since the last full or incremental backup), you should rotate the binary log by using *Note `FLUSH LOGS': flush. This done, you need to copy to the backup location all binary logs which range from the one of the moment of the last full or incremental backup to the last but one. These binary logs are the incremental backup; at restore time, you apply them as explained in *Note point-in-time-recovery::. The next time you do a full backup, you should also rotate the binary log using *Note `FLUSH LOGS': flush, *Note `mysqldump --flush-logs': mysqldump, or *Note `mysqlhotcopy --flushlog': mysqlhotcopy. See *Note mysqldump::, and *Note mysqlhotcopy::. * Making Backups Using Replication Slaves * If you have performance problems with your master server while making backups, one strategy that can help is to set up replication and perform backups on the slave rather than on the master. See *Note replication-solutions-backups::. If you are backing up a slave replication server, you should back up its `master.info' and `relay-log.info' files when you back up the slave's databases, regardless of the backup method you choose. These information files are always needed to resume replication after you restore the slave's data. If your slave is replicating *Note `LOAD DATA INFILE': load-data. statements, you should also back up any `SQL_LOAD-*' files that exist in the directory that the slave uses for this purpose. The slave needs these files to resume replication of any interrupted *Note `LOAD DATA INFILE': load-data. operations. The location of this directory is the value of the `--slave-load-tmpdir' option. If the server was not started with that option, the directory location is the value of the `tmpdir' system variable. * Recovering Corrupt Tables * If you have to restore `MyISAM' tables that have become corrupt, try to recover them using *Note `REPAIR TABLE': repair-table. or *Note `myisamchk -r': myisamchk. first. That should work in 99.9% of all cases. If *Note `myisamchk': myisamchk. fails, see *Note myisam-table-maintenance::. * Making Backups Using a File System Snapshot * If you are using a Veritas file system, you can make a backup like this: 1. From a client program, execute *Note `FLUSH TABLES WITH READ LOCK': flush. 2. From another shell, execute `mount vxfs snapshot'. 3. From the first client, execute *Note `UNLOCK TABLES': lock-tables. 4. Copy files from the snapshot. 5. Unmount the snapshot. Similar snapshot capabilities may be available in other file systems, such as LVM or ZFS.  File: manual.info, Node: backup-strategy-example, Next: using-mysqldump, Prev: backup-methods, Up: backup-and-recovery 7.3 Example Backup and Recovery Strategy ======================================== * Menu: * backup-policy:: Establishing a Backup Policy * recovery-from-backups:: Using Backups for Recovery * backup-strategy-summary:: Backup Strategy Summary This section discusses a procedure for performing backups that enables you to recover data after several types of crashes: * Operating system crash * Power failure * File system crash * Hardware problem (hard drive, motherboard, and so forth) The example commands do not include options such as `--user' and `--password' for the *Note `mysqldump': mysqldump. and *Note `mysql': mysql. client programs. You should include such options as necessary to enable client programs to connect to the MySQL server. Assume that data is stored in the `InnoDB' storage engine, which has support for transactions and automatic crash recovery. Assume also that the MySQL server is under load at the time of the crash. If it were not, no recovery would ever be needed. For cases of operating system crashes or power failures, we can assume that MySQL's disk data is available after a restart. The `InnoDB' data files might not contain consistent data due to the crash, but `InnoDB' reads its logs and finds in them the list of pending committed and noncommitted transactions that have not been flushed to the data files. `InnoDB' automatically rolls back those transactions that were not committed, and flushes to its data files those that were committed. Information about this recovery process is conveyed to the user through the MySQL error log. The following is an example log excerpt: InnoDB: Database was not shut down normally. InnoDB: Starting recovery from log files... InnoDB: Starting log scan based on checkpoint at InnoDB: log sequence number 0 13674004 InnoDB: Doing recovery: scanned up to log sequence number 0 13739520 InnoDB: Doing recovery: scanned up to log sequence number 0 13805056 InnoDB: Doing recovery: scanned up to log sequence number 0 13870592 InnoDB: Doing recovery: scanned up to log sequence number 0 13936128 ... InnoDB: Doing recovery: scanned up to log sequence number 0 20555264 InnoDB: Doing recovery: scanned up to log sequence number 0 20620800 InnoDB: Doing recovery: scanned up to log sequence number 0 20664692 InnoDB: 1 uncommitted transaction(s) which must be rolled back InnoDB: Starting rollback of uncommitted transactions InnoDB: Rolling back trx no 16745 InnoDB: Rolling back of trx no 16745 completed InnoDB: Rollback of uncommitted transactions completed InnoDB: Starting an apply batch of log records to the database... InnoDB: Apply batch completed InnoDB: Started mysqld: ready for connections For the cases of file system crashes or hardware problems, we can assume that the MySQL disk data is _not_ available after a restart. This means that MySQL fails to start successfully because some blocks of disk data are no longer readable. In this case, it is necessary to reformat the disk, install a new one, or otherwise correct the underlying problem. Then it is necessary to recover our MySQL data from backups, which means that backups must already have been made. To make sure that is the case, design and implement a backup policy.  File: manual.info, Node: backup-policy, Next: recovery-from-backups, Prev: backup-strategy-example, Up: backup-strategy-example 7.3.1 Establishing a Backup Policy ---------------------------------- To be useful, backups must be scheduled regularly. A full backup (a snapshot of the data at a point in time) can be done in MySQL with several tools. For example, `InnoDB Hot Backup' provides online nonblocking physical backup of the `InnoDB' data files, and *Note `mysqldump': mysqldump. provides online logical backup. This discussion uses *Note `mysqldump': mysqldump. Assume that we make a full backup of all our `InnoDB' tables in all databases using the following command on Sunday at 1 p.m., when load is low: shell> mysqldump --single-transaction --all-databases > backup_sunday_1_PM.sql The resulting `.sql' file produced by *Note `mysqldump': mysqldump. contains a set of SQL *Note `INSERT': insert. statements that can be used to reload the dumped tables at a later time. This backup operation acquires a global read lock on all tables at the beginning of the dump (using *Note `FLUSH TABLES WITH READ LOCK': flush.). As soon as this lock has been acquired, the binary log coordinates are read and the lock is released. If long updating statements are running when the *Note `FLUSH': flush. statement is issued, the backup operation may stall until those statements finish. After that, the dump becomes lock-free and does not disturb reads and writes on the tables. It was assumed earlier that the tables to back up are `InnoDB' tables, so `--single-transaction' uses a consistent read and guarantees that data seen by *Note `mysqldump': mysqldump. does not change. (Changes made by other clients to `InnoDB' tables are not seen by the *Note `mysqldump': mysqldump. process.) If the backup operation includes nontransactional tables, consistency requires that they do not change during the backup. For example, for the `MyISAM' tables in the `mysql' database, there must be no administrative changes to MySQL accounts during the backup. Full backups are necessary, but it is not always convenient to create them. They produce large backup files and take time to generate. They are not optimal in the sense that each successive full backup includes all data, even that part that has not changed since the previous full backup. It is more efficient to make an initial full backup, and then to make incremental backups. The incremental backups are smaller and take less time to produce. The tradeoff is that, at recovery time, you cannot restore your data just by reloading the full backup. You must also process the incremental backups to recover the incremental changes. To make incremental backups, we need to save the incremental changes. In MySQL, these changes are represented in the binary log, so the MySQL server should always be started with the `--log-bin' option to enable that log. With binary logging enabled, the server writes each data change into a file while it updates data. Looking at the data directory of a MySQL server that was started with the `--log-bin' option and that has been running for some days, we find these MySQL binary log files: -rw-rw---- 1 guilhem guilhem 1277324 Nov 10 23:59 gbichot2-bin.000001 -rw-rw---- 1 guilhem guilhem 4 Nov 10 23:59 gbichot2-bin.000002 -rw-rw---- 1 guilhem guilhem 79 Nov 11 11:06 gbichot2-bin.000003 -rw-rw---- 1 guilhem guilhem 508 Nov 11 11:08 gbichot2-bin.000004 -rw-rw---- 1 guilhem guilhem 220047446 Nov 12 16:47 gbichot2-bin.000005 -rw-rw---- 1 guilhem guilhem 998412 Nov 14 10:08 gbichot2-bin.000006 -rw-rw---- 1 guilhem guilhem 361 Nov 14 10:07 gbichot2-bin.index Each time it restarts, the MySQL server creates a new binary log file using the next number in the sequence. While the server is running, you can also tell it to close the current binary log file and begin a new one manually by issuing a *Note `FLUSH LOGS': flush. SQL statement or with a *Note `mysqladmin flush-logs': mysqladmin. command. *Note `mysqldump': mysqldump. also has an option to flush the logs. The `.index' file in the data directory contains the list of all MySQL binary logs in the directory. The MySQL binary logs are important for recovery because they form the set of incremental backups. If you make sure to flush the logs when you make your full backup, the binary log files created afterward contain all the data changes made since the backup. Let's modify the previous *Note `mysqldump': mysqldump. command a bit so that it flushes the MySQL binary logs at the moment of the full backup, and so that the dump file contains the name of the new current binary log: shell> mysqldump --single-transaction --flush-logs --master-data=2 \ --all-databases > backup_sunday_1_PM.sql After executing this command, the data directory contains a new binary log file, `gbichot2-bin.000007', because the `--flush-logs' option causes the server to flush its logs. The `--master-data' option causes *Note `mysqldump': mysqldump. to write binary log information to its output, so the resulting `.sql' dump file includes these lines: -- Position to start replication or point-in-time recovery from -- CHANGE MASTER TO MASTER_LOG_FILE='gbichot2-bin.000007',MASTER_LOG_POS=4; Because the *Note `mysqldump': mysqldump. command made a full backup, those lines mean two things: * The dump file contains all changes made before any changes written to the `gbichot2-bin.000007' binary log file or newer. * All data changes logged after the backup are not present in the dump file, but are present in the `gbichot2-bin.000007' binary log file or newer. On Monday at 1 p.m., we can create an incremental backup by flushing the logs to begin a new binary log file. For example, executing a *Note `mysqladmin flush-logs': mysqladmin. command creates `gbichot2-bin.000008'. All changes between the Sunday 1 p.m. full backup and Monday 1 p.m. will be in the `gbichot2-bin.000007' file. This incremental backup is important, so it is a good idea to copy it to a safe place. (For example, back it up on tape or DVD, or copy it to another machine.) On Tuesday at 1 p.m., execute another *Note `mysqladmin flush-logs': mysqladmin. command. All changes between Monday 1 p.m. and Tuesday 1 p.m. will be in the `gbichot2-bin.000008' file (which also should be copied somewhere safe). The MySQL binary logs take up disk space. To free up space, purge them from time to time. One way to do this is by deleting the binary logs that are no longer needed, such as when we make a full backup: shell> mysqldump --single-transaction --flush-logs --master-data=2 \ --all-databases --delete-master-logs > backup_sunday_1_PM.sql *Note*: Deleting the MySQL binary logs with *Note `mysqldump --delete-master-logs': mysqldump. can be dangerous if your server is a replication master server, because slave servers might not yet fully have processed the contents of the binary log. The description for the *Note `PURGE BINARY LOGS': purge-binary-logs. statement explains what should be verified before deleting the MySQL binary logs. See *Note purge-binary-logs::.  File: manual.info, Node: recovery-from-backups, Next: backup-strategy-summary, Prev: backup-policy, Up: backup-strategy-example 7.3.2 Using Backups for Recovery -------------------------------- Now, suppose that we have a catastrophic crash on Wednesday at 8 a.m. that requires recovery from backups. To recover, first we restore the last full backup we have (the one from Sunday 1 p.m.). The full backup file is just a set of SQL statements, so restoring it is very easy: shell> mysql < backup_sunday_1_PM.sql At this point, the data is restored to its state as of Sunday 1 p.m.. To restore the changes made since then, we must use the incremental backups; that is, the `gbichot2-bin.000007' and `gbichot2-bin.000008' binary log files. Fetch the files if necessary from where they were backed up, and then process their contents like this: shell> mysqlbinlog gbichot2-bin.000007 gbichot2-bin.000008 | mysql We now have recovered the data to its state as of Tuesday 1 p.m., but still are missing the changes from that date to the date of the crash. To not lose them, we would have needed to have the MySQL server store its MySQL binary logs into a safe location (RAID disks, SAN, ...) different from the place where it stores its data files, so that these logs were not on the destroyed disk. (That is, we can start the server with a `--log-bin' option that specifies a location on a different physical device from the one on which the data directory resides. That way, the logs are safe even if the device containing the directory is lost.) If we had done this, we would have the `gbichot2-bin.000009' file (and any subsequent files) at hand, and we could apply them using *Note `mysqlbinlog': mysqlbinlog. and *Note `mysql': mysql. to restore the most recent data changes with no loss up to the moment of the crash: shell> mysqlbinlog gbichot2-bin.000009 ... | mysql For more information about using *Note `mysqlbinlog': mysqlbinlog. to process binary log files, see *Note point-in-time-recovery::.  File: manual.info, Node: backup-strategy-summary, Prev: recovery-from-backups, Up: backup-strategy-example 7.3.3 Backup Strategy Summary ----------------------------- In case of an operating system crash or power failure, `InnoDB' itself does all the job of recovering data. But to make sure that you can sleep well, observe the following guidelines: * Always run the MySQL server with the `--log-bin' option, or even `--log-bin=LOG_NAME', where the log file name is located on some safe media different from the drive on which the data directory is located. If you have such safe media, this technique can also be good for disk load balancing (which results in a performance improvement). * Make periodic full backups, using the *Note `mysqldump': mysqldump. command shown earlier in *Note backup-policy::, that makes an online, nonblocking backup. * Make periodic incremental backups by flushing the logs with *Note `FLUSH LOGS': flush. or *Note `mysqladmin flush-logs': mysqladmin.  File: manual.info, Node: using-mysqldump, Next: point-in-time-recovery, Prev: backup-strategy-example, Up: backup-and-recovery 7.4 Using `mysqldump' for Backups ================================= * Menu: * mysqldump-sql-format:: Dumping Data in SQL Format with `mysqldump' * reloading-sql-format-dumps:: Reloading SQL-Format Backups * mysqldump-delimited-text:: Dumping Data in Delimited-Text Format with `mysqldump' * reloading-delimited-text-dumps:: Reloading Delimited-Text Format Backups * mysqldump-tips:: `mysqldump' Tips This section describes how to use *Note `mysqldump': mysqldump. to produce dump files, and how to reload dump files. A dump file can be used in several ways: * As a backup to enable data recovery in case of data loss. * As a source of data for setting up replication slaves. * As a source of data for experimentation: * To make a copy of a database that you can use without changing the original data. * To test potential upgrade incompatibilities. *Note `mysqldump': mysqldump. produces two types of output, depending on whether the `--tab' option is given: * Without `--tab', *Note `mysqldump': mysqldump. writes SQL statements to the standard output. This output consists of `CREATE' statements to create dumped objects (databases, tables, stored routines, and so forth), and `INSERT' statements to load data into tables. The output can be saved in a file and reloaded later using *Note `mysql': mysql. to recreate the dumped objects. Options are available to modify the format of the SQL statements, and to control which objects are dumped. * With `--tab', *Note `mysqldump': mysqldump. produces two output files for each dumped table. The server writes one file as tab-delimited text, one line per table row. This file is named `TBL_NAME.txt' in the output directory. The server also sends a *Note `CREATE TABLE': create-table. statement for the table to *Note `mysqldump': mysqldump, which writes it as a file named `TBL_NAME.sql' in the output directory.  File: manual.info, Node: mysqldump-sql-format, Next: reloading-sql-format-dumps, Prev: using-mysqldump, Up: using-mysqldump 7.4.1 Dumping Data in SQL Format with `mysqldump' ------------------------------------------------- This section describes how to use *Note `mysqldump': mysqldump. to create SQL-format dump files. For information about reloading such dump files, see *Note reloading-sql-format-dumps::. By default, *Note `mysqldump': mysqldump. writes information as SQL statements to the standard output. You can save the output in a file: shell> mysqldump [ARGUMENTS] > FILE_NAME To dump all databases, invoke *Note `mysqldump': mysqldump. with the `--all-databases' option: shell> mysqldump --all-databases > dump.sql To dump only specific databases, name them on the command line and use the `--databases' option: shell> mysqldump --databases db1 db2 db3 > dump.sql The `--databases' option causes all names on the command line to be treated as database names. Without this option, *Note `mysqldump': mysqldump. treats the first name as a database name and those following as table names. With `--all-databases' or `--databases', *Note `mysqldump': mysqldump. writes *Note `CREATE DATABASE': create-database. and *Note `USE': use. statements prior to the dump output for each database. This ensures that when the dump file is reloaded, it creates each database if it does not exist and makes it the default database so database contents are loaded into the same database from which they came. If you want to cause the dump file to force a drop of each database before recreating it, use the `--add-drop-database' option as well. In this case, *Note `mysqldump': mysqldump. writes a *Note `DROP DATABASE': drop-database. statement preceding each *Note `CREATE DATABASE': create-database. statement. To dump a single database, name it on the command line: shell> mysqldump --databases test > dump.sql In the single-database case, it is permissible to omit the `--databases' option: shell> mysqldump test > dump.sql The difference between the two preceding commands is that without `--databases', the dump output contains no *Note `CREATE DATABASE': create-database. or *Note `USE': use. statements. This has several implications: * When you reload the dump file, you must specify a default database name so that the server knows which database to reload. * For reloading, you can specify a database name different from the original name, which enables you to reload the data into a different database. * If the database to be reloaded does not exist, you must create it first. * Because the output will contain no *Note `CREATE DATABASE': create-database. statement, the `--add-drop-database' option has no effect. If you use it, it produces no *Note `DROP DATABASE': drop-database. statement. To dump only specific tables from a database, name them on the command line following the database name: shell> mysqldump test t1 t3 t7 > dump.sql  File: manual.info, Node: reloading-sql-format-dumps, Next: mysqldump-delimited-text, Prev: mysqldump-sql-format, Up: using-mysqldump 7.4.2 Reloading SQL-Format Backups ---------------------------------- To reload a dump file written by *Note `mysqldump': mysqldump. that consists of SQL statements, use it as input to the *Note `mysql': mysql. client. If the dump file was created by *Note `mysqldump': mysqldump. with the `--all-databases' or `--databases' option, it contains *Note `CREATE DATABASE': create-database. and *Note `USE': use. statements and it is not necessary to specify a default database into which to load the data: shell> mysql < dump.sql Alternatively, from within *Note `mysql': mysql, use a `source' command: mysql> source dump.sql If the file is a single-database dump not containing *Note `CREATE DATABASE': create-database. and *Note `USE': use. statements, create the database first (if necessary): shell> mysqladmin create db1 Then specify the database name when you load the dump file: shell> mysql db1 < dump.sql Alternatively, from within *Note `mysql': mysql, create the database, select it as the default database, and load the dump file: mysql> CREATE DATABASE IF NOT EXISTS db1; mysql> USE db1; mysql> source dump.sql  File: manual.info, Node: mysqldump-delimited-text, Next: reloading-delimited-text-dumps, Prev: reloading-sql-format-dumps, Up: using-mysqldump 7.4.3 Dumping Data in Delimited-Text Format with `mysqldump' ------------------------------------------------------------ This section describes how to use *Note `mysqldump': mysqldump. to create delimited-text dump files. For information about reloading such dump files, see *Note reloading-delimited-text-dumps::. If you invoke *Note `mysqldump': mysqldump. with the `--tab=DIR_NAME' option, it uses DIR_NAME as the output directory and dumps tables individually in that directory using two files for each table. The table name is the basename for these files. For a table named `t1', the files are named `t1.sql' and `t1.txt'. The `.sql' file contains a *Note `CREATE TABLE': create-table. statement for the table. The `.txt' file contains the table data, one line per table row. The following command dumps the contents of the `db1' database to files in the `/tmp' database: shell> mysqldump --tab=/tmp db1 The `.txt' files containing table data are written by the server, so they are owned by the system account used for running the server. The server uses *Note `SELECT ... INTO OUTFILE': select. to write the files, so you must have the `FILE' privilege to perform this operation, and an error occurs if a given `.txt' file already exists. The server sends the `CREATE' definitions for dumped tables to *Note `mysqldump': mysqldump, which writes them to `.sql' files. These files therefore are owned by the user who executes *Note `mysqldump': mysqldump. It is best that `--tab' be used only for dumping a local server. If you use it with a remote server, the `--tab' directory must exist on both the local and remote hosts, and the `.txt' files will be written by the server in the remote directory (on the server host), whereas the `.sql' files will be written by *Note `mysqldump': mysqldump. in the local directory (on the client host). For *Note `mysqldump --tab': mysqldump, the server by default writes table data to `.txt' files one line per row with tabs between column values, no quotation marks around column values, and newline as the line terminator. (These are the same defaults as for *Note `SELECT ... INTO OUTFILE': select.) To enable data files to be written using a different format, *Note `mysqldump': mysqldump. supports these options: * `--fields-terminated-by=STR' The string for separating column values (default: tab). * `--fields-enclosed-by=CHAR' The character within which to enclose column values (default: no character). * `--fields-optionally-enclosed-by=CHAR' The character within which to enclose non-numeric column values (default: no character). * `--fields-escaped-by=CHAR' The character for escaping special characters (default: no escaping). * `--lines-terminated-by=STR' The line-termination string (default: newline). Depending on the value you specify for any of these options, it might be necessary on the command line to quote or escape the value appropriately for your command interpreter. Alternatively, specify the value using hex notation. Suppose that you want *Note `mysqldump': mysqldump. to quote column values within double quotation marks. To do so, specify double quote as the value for the `--fields-enclosed-by' option. But this character is often special to command interpreters and must be treated specially. For example, on Unix, you can quote the double quote like this: --fields-enclosed-by='"' On any platform, you can specify the value in hex: --fields-enclosed-by=0x22 It is common to use several of the data-formatting options together. For example, to dump tables in comma-separated values format with lines terminated by carriage-return/newline pairs (`\r\n'), use this command (enter it on a single line): shell> mysqldump --tab=/tmp --fields-terminated-by=, --fields-enclosed-by='"' --lines-terminated-by=0x0d0a db1 Should you use any of the data-formatting options to dump table data, you will need to specify the same format when you reload data files later, to ensure proper interpretation of the file contents.  File: manual.info, Node: reloading-delimited-text-dumps, Next: mysqldump-tips, Prev: mysqldump-delimited-text, Up: using-mysqldump 7.4.4 Reloading Delimited-Text Format Backups --------------------------------------------- For backups produced with *Note `mysqldump --tab': mysqldump, each table is represented in the output directory by an `.sql' file containing the *Note `CREATE TABLE': create-table. statement for the table, and a `.txt' file containing the table data. To reload a table, first change location into the output directory. Then process the `.sql' file with *Note `mysql': mysql. to create an empty table and process the `.txt' file to load the data into the table: shell> mysql db1 < t1.sql shell> mysqlimport db1 t1.txt An alternative to using *Note `mysqlimport': mysqlimport. to load the data file is to use the *Note `LOAD DATA INFILE': load-data. statement from within the *Note `mysql': mysql. client: mysql> USE db1; mysql> LOAD DATA INFILE 't1.txt' INTO TABLE t1; If you used any data-formatting options with *Note `mysqldump': mysqldump. when you initially dumped the table, you must use the same options with *Note `mysqlimport': mysqlimport. or *Note `LOAD DATA INFILE': load-data. to ensure proper interpretation of the data file contents: shell> mysqlimport --fields-terminated-by=, --fields-enclosed-by='"' --lines-terminated-by=0x0d0a db1 t1.txt Or: mysql> USE db1; mysql> LOAD DATA INFILE 't1.txt' INTO TABLE t1 -> FIELDS TERMINATED BY ',' FIELDS ENCLOSED BY '"' -> LINES TERMINATED BY '\r\n';  File: manual.info, Node: mysqldump-tips, Prev: reloading-delimited-text-dumps, Up: using-mysqldump 7.4.5 `mysqldump' Tips ---------------------- * Menu: * mysqldump-copying-database:: Making a Copy of a Database * mysqldump-copying-to-other-server:: Copy a Database from one Server to Another * mysqldump-stored-programs:: Dumping Stored Programs * mysqldump-definition-data-dumps:: Dumping Table Definitions and Content Separately * mysqldump-upgrade-testing:: Using `mysqldump' to Test for Upgrade Incompatibilities This section surveys techniques that enable you to use *Note `mysqldump': mysqldump. to solve specific problems: * How to make a copy a database * How to copy a database from one server to another * How to dump stored programs (stored procedures and functions, triggers, and events) * How to dump definitions and data separately  File: manual.info, Node: mysqldump-copying-database, Next: mysqldump-copying-to-other-server, Prev: mysqldump-tips, Up: mysqldump-tips 7.4.5.1 Making a Copy of a Database ................................... shell> mysqldump db1 > dump.sql shell> mysqladmin create db2 shell> mysql db2 < dump.sql Do not use `--databases' on the *Note `mysqldump': mysqldump. command line because that causes `USE db1' to be included in the dump file, which overrides the effect of naming `db2' on the *Note `mysql': mysql. command line.  File: manual.info, Node: mysqldump-copying-to-other-server, Next: mysqldump-stored-programs, Prev: mysqldump-copying-database, Up: mysqldump-tips 7.4.5.2 Copy a Database from one Server to Another .................................................. On Server 1: shell> mysqldump --databases db1 > dump.sql Copy the dump file from Server 1 to Server 2. On Server 2: shell> mysql < dump.sql Use of `--databases' with the *Note `mysqldump': mysqldump. command line causes the dump file to include *Note `CREATE DATABASE': create-database. and *Note `USE': use. statements that create the database if it does exist and make it the default database for the reloaded data. Alternatively, you can omit `--databases' from the *Note `mysqldump': mysqldump. command. Then you will need to create the database on Server 2 (if necessary) and specify it as the default database when you reload the dump file. On Server 1: shell> mysqldump db1 > dump.sql On Server 2: shell> mysqladmin create db1 shell> mysql db1 < dump.sql You can specify a different database name in this case, so omitting `--databases' from the *Note `mysqldump': mysqldump. command enables you to dump data from one database and load it into another.  File: manual.info, Node: mysqldump-stored-programs, Next: mysqldump-definition-data-dumps, Prev: mysqldump-copying-to-other-server, Up: mysqldump-tips 7.4.5.3 Dumping Stored Programs ............................... Several options control how *Note `mysqldump': mysqldump. handles stored programs (stored procedures and functions, triggers, and events): * `--events': Dump Event Scheduler events * `--routines': Dump stored procedures and functions * `--triggers': Dump triggers for tables The `--triggers' option is enabled by default so that when tables are dumped, they are accompanied by any triggers they have. The other options are disabled by default and must be specified explicitly to dump the corresponding objects. To disable any of these options explicitly, use its skip form: `--skip-events', `--skip-routines', or `--skip-triggers'.  File: manual.info, Node: mysqldump-definition-data-dumps, Next: mysqldump-upgrade-testing, Prev: mysqldump-stored-programs, Up: mysqldump-tips 7.4.5.4 Dumping Table Definitions and Content Separately ........................................................ The `--no-data' option tells *Note `mysqldump': mysqldump. not to dump table data, resulting in the dump file containing only statements to create the tables. Conversely, the `--no-create-info' option tells *Note `mysqldump': mysqldump. to suppress `CREATE' statements from the output, so that the dump file contains only table data. For example, to dump table definitions and data separately for the `test' database, use these commands: shell> mysqldump --no-data test > dump-defs.sql shell> mysqldump --no-create-info test > dump-data.sql For a definition-only dump, add the `--routines' and `--events' options to also include stored routine and event definitions: shell> mysqldump --no-data --routines --events test > dump-defs.sql  File: manual.info, Node: mysqldump-upgrade-testing, Prev: mysqldump-definition-data-dumps, Up: mysqldump-tips 7.4.5.5 Using `mysqldump' to Test for Upgrade Incompatibilities ............................................................... When contemplating a MySQL upgrade, it is prudent to install the newer version separately from your current production version. Then you can dump the database and database object definitions from the production server and load them into the new server to verify that they are handled properly. (This is also useful for testing downgrades.) On the production server: shell> mysqldump --all-databases --no-data --routines --events > dump-defs.sql On the upgraded server: shell> mysql < dump-defs.sql Because the dump file does not contain table data, it can be processed quickly. This enables you to spot potential incompatibilities without waiting for lengthy data-loading operations. Look for warnings or errors while the dump file is being processed. After you have verified that the definitions are handled properly, dump the data and try to load it into the upgraded server. On the production server: shell> mysqldump --all-databases --no-create-info > dump-data.sql On the upgraded server: shell> mysql < dump-data.sql Now check the table contents and run some test queries.  File: manual.info, Node: point-in-time-recovery, Next: myisam-table-maintenance, Prev: using-mysqldump, Up: backup-and-recovery 7.5 Point-in-Time (Incremental) Recovery Using the Binary Log ============================================================= * Menu: * point-in-time-recovery-times:: Point-in-Time Recovery Using Event Times * point-in-time-recovery-positions:: Point-in-Time Recovery Using Event Positions Point-in-time recovery refers to recovery of data changes made since a given point in time. Typically, this type of recovery is performed after restoring a full backup that brings the server to its state as of the time the backup was made. (The full backup can be made in several ways, such as those listed in *Note backup-methods::.) Point-in-time recovery then brings the server up to date incrementally from the time of the full backup to a more recent time. Point-in-time recovery is based on these principles: * The source of information for point-in-time recovery is the set of incremental backups represented by the binary log files generated subsequent to the full backup operation. Therefore, the server must be started with the `--log-bin' option to enable binary logging (see *Note binary-log::). To restore data from the binary log, you must know the name and location of the current binary log files. By default, the server creates binary log files in the data directory, but a path name can be specified with the `--log-bin' option to place the files in a different location. *Note binary-log::. To see a listing of all binary log files, use this statement: mysql> SHOW BINARY LOGS; To determine the name of the current binary log file, issue the following statement: mysql> SHOW MASTER STATUS; * The *Note `mysqlbinlog': mysqlbinlog. utility converts the events in the binary log files from binary format to text so that they can be executed or viewed. *Note `mysqlbinlog': mysqlbinlog. has options for selecting sections of the binary log based on event times or position of events within the log. See *Note mysqlbinlog::. * Executing events from the binary log causes the data modifications they represent to be redone. This enables recovery of data changes for a given span of time. To execute events from the binary log, process *Note `mysqlbinlog': mysqlbinlog. output using the *Note `mysql': mysql. client: shell> mysqlbinlog BINLOG_FILES | mysql -u root -p * Viewing log contents can be useful when you need to determine event times or positions to select partial log contents prior to executing events. To view events from the log, send *Note `mysqlbinlog': mysqlbinlog. output into a paging program: shell> mysqlbinlog BINLOG_FILES | more Alternatively, save the output in a file and view the file in a text editor: shell> mysqlbinlog BINLOG_FILES > tmpfile shell> ... EDIT TMPFILE ... * Saving the output in a file is useful as a preliminary to executing the log contents with certain events removed, such as an accidental *Note `DROP DATABASE': drop-database. You can delete from the file any statements not to be executed before executing its contents. After editing the file, execute the contents as follows: shell> mysql -u root -p < tmpfile If you have more than one binary log to execute on the MySQL server, the safe method is to process them all using a single connection to the server. Here is an example that demonstrates what may be _unsafe_: shell> mysqlbinlog binlog.000001 | mysql -u root -p # DANGER!! shell> mysqlbinlog binlog.000002 | mysql -u root -p # DANGER!! Processing binary logs this way using different connections to the server causes problems if the first log file contains a *Note `CREATE TEMPORARY TABLE': create-table. statement and the second log contains a statement that uses the temporary table. When the first *Note `mysql': mysql. process terminates, the server drops the temporary table. When the second *Note `mysql': mysql. process attempts to use the table, the server reports `unknown table.' To avoid problems like this, use a _single_ connection to execute the contents of all binary logs that you want to process. Here is one way to do so: shell> mysqlbinlog binlog.000001 binlog.000002 | mysql -u root -p Another approach is to write all the logs to a single file and then process the file: shell> mysqlbinlog binlog.000001 > /tmp/statements.sql shell> mysqlbinlog binlog.000002 >> /tmp/statements.sql shell> mysql -u root -p -e "source /tmp/statements.sql"  File: manual.info, Node: point-in-time-recovery-times, Next: point-in-time-recovery-positions, Prev: point-in-time-recovery, Up: point-in-time-recovery 7.5.1 Point-in-Time Recovery Using Event Times ---------------------------------------------- To indicate the start and end times for recovery, specify the `--start-datetime' and `--stop-datetime' options for *Note `mysqlbinlog': mysqlbinlog, in *Note `DATETIME': datetime. format. As an example, suppose that exactly at 10:00 a.m. on April 20, 2005 an SQL statement was executed that deleted a large table. To restore the table and data, you could restore the previous night's backup, and then execute the following command: shell> mysqlbinlog --stop-datetime="2005-04-20 9:59:59" \ /var/log/mysql/bin.123456 | mysql -u root -p This command recovers all of the data up until the date and time given by the `--stop-datetime' option. If you did not detect the erroneous SQL statement that was entered until hours later, you will probably also want to recover the activity that occurred afterward. Based on this, you could run *Note `mysqlbinlog': mysqlbinlog. again with a start date and time, like so: shell> mysqlbinlog --start-datetime="2005-04-20 10:01:00" \ /var/log/mysql/bin.123456 | mysql -u root -p In this command, the SQL statements logged from 10:01 a.m. on will be re-executed. The combination of restoring of the previous night's dump file and the two *Note `mysqlbinlog': mysqlbinlog. commands restores everything up until one second before 10:00 a.m. and everything from 10:01 a.m. on. To use this method of point-in-time recovery, you should examine the log to be sure of the exact times to specify for the commands. To display the log file contents without executing them, use this command: shell> mysqlbinlog /var/log/mysql/bin.123456 > /tmp/mysql_restore.sql Then open the `/tmp/mysql_restore.sql' file with a text editor to examine it. Excluding specific changes by specifying times for *Note `mysqlbinlog': mysqlbinlog. does not work well if multiple statements executed at the same time as the one to be excluded.  File: manual.info, Node: point-in-time-recovery-positions, Prev: point-in-time-recovery-times, Up: point-in-time-recovery 7.5.2 Point-in-Time Recovery Using Event Positions -------------------------------------------------- Instead of specifying dates and times, the `--start-position' and `--stop-position' options for *Note `mysqlbinlog': mysqlbinlog. can be used for specifying log positions. They work the same as the start and stop date options, except that you specify log position numbers rather than dates. Using positions may enable you to be more precise about which part of the log to recover, especially if many transactions occurred around the same time as a damaging SQL statement. To determine the position numbers, run *Note `mysqlbinlog': mysqlbinlog. for a range of times near the time when the unwanted transaction was executed, but redirect the results to a text file for examination. This can be done like so: shell> mysqlbinlog --start-datetime="2005-04-20 9:55:00" \ --stop-datetime="2005-04-20 10:05:00" \ /var/log/mysql/bin.123456 > /tmp/mysql_restore.sql This command creates a small text file in the `/tmp' directory that contains the SQL statements around the time that the deleterious SQL statement was executed. Open this file with a text editor and look for the statement that you do not want to repeat. Determine the positions in the binary log for stopping and resuming the recovery and make note of them. Positions are labeled as `log_pos' followed by a number. After restoring the previous backup file, use the position numbers to process the binary log file. For example, you would use commands something like these: shell> mysqlbinlog --stop-position=368312 /var/log/mysql/bin.123456 \ | mysql -u root -p shell> mysqlbinlog --start-position=368315 /var/log/mysql/bin.123456 \ | mysql -u root -p The first command recovers all the transactions up until the stop position given. The second command recovers all transactions from the starting position given until the end of the binary log. Because the output of *Note `mysqlbinlog': mysqlbinlog. includes `SET TIMESTAMP' statements before each SQL statement recorded, the recovered data and related MySQL logs will reflect the original times at which the transactions were executed.  File: manual.info, Node: myisam-table-maintenance, Prev: point-in-time-recovery, Up: backup-and-recovery 7.6 `MyISAM' Table Maintenance and Crash Recovery ================================================= * Menu: * myisam-crash-recovery:: Using `myisamchk' for Crash Recovery * myisam-check:: How to Check `MyISAM' Tables for Errors * myisam-repair:: How to Repair `MyISAM' Tables * myisam-optimization:: `MyISAM' Table Optimization * myisam-maintenance-schedule:: Setting Up a `MyISAM' Table Maintenance Schedule This section discusses how to use *Note `myisamchk': myisamchk. to check or repair `MyISAM' tables (tables that have `.MYD' and `.MYI' files for storing data and indexes). For general *Note `myisamchk': myisamchk. background, see *Note myisamchk::. Other table-repair information can be found at *Note rebuilding-tables::. You can use *Note `myisamchk': myisamchk. to check, repair, or optimize database tables. The following sections describe how to perform these operations and how to set up a table maintenance schedule. For information about using *Note `myisamchk': myisamchk. to get information about your tables, see *Note myisamchk-table-info::. Even though table repair with *Note `myisamchk': myisamchk. is quite secure, it is always a good idea to make a backup _before_ doing a repair or any maintenance operation that could make a lot of changes to a table. *Note `myisamchk': myisamchk. operations that affect indexes can cause `FULLTEXT' indexes to be rebuilt with full-text parameters that are incompatible with the values used by the MySQL server. To avoid this problem, follow the guidelines in *Note myisamchk-general-options::. `MyISAM' table maintenance can also be done using the SQL statements that perform operations similar to what *Note `myisamchk': myisamchk. can do: * To check `MyISAM' tables, use *Note `CHECK TABLE': check-table. * To repair `MyISAM' tables, use *Note `REPAIR TABLE': repair-table. * To optimize `MyISAM' tables, use *Note `OPTIMIZE TABLE': optimize-table. * To analyze `MyISAM' tables, use *Note `ANALYZE TABLE': analyze-table. For additional information about these statements, see *Note table-maintenance-sql::. These statements can be used directly or by means of the *Note `mysqlcheck': mysqlcheck. client program. One advantage of these statements over *Note `myisamchk': myisamchk. is that the server does all the work. With *Note `myisamchk': myisamchk, you must make sure that the server does not use the tables at the same time so that there is no unwanted interaction between *Note `myisamchk': myisamchk. and the server.  File: manual.info, Node: myisam-crash-recovery, Next: myisam-check, Prev: myisam-table-maintenance, Up: myisam-table-maintenance 7.6.1 Using `myisamchk' for Crash Recovery ------------------------------------------ This section describes how to check for and deal with data corruption in MySQL databases. If your tables become corrupted frequently, you should try to find the reason why. See *Note crashing::. For an explanation of how `MyISAM' tables can become corrupted, see *Note myisam-table-problems::. If you run *Note `mysqld': mysqld. with external locking disabled (which is the default), you cannot reliably use *Note `myisamchk': myisamchk. to check a table when *Note `mysqld': mysqld. is using the same table. If you can be certain that no one will access the tables through *Note `mysqld': mysqld. while you run *Note `myisamchk': myisamchk, you only have to execute *Note `mysqladmin flush-tables': mysqladmin. before you start checking the tables. If you cannot guarantee this, you must stop *Note `mysqld': mysqld. while you check the tables. If you run *Note `myisamchk': myisamchk. to check tables that *Note `mysqld': mysqld. is updating at the same time, you may get a warning that a table is corrupt even when it is not. If the server is run with external locking enabled, you can use *Note `myisamchk': myisamchk. to check tables at any time. In this case, if the server tries to update a table that *Note `myisamchk': myisamchk. is using, the server will wait for *Note `myisamchk': myisamchk. to finish before it continues. If you use *Note `myisamchk': myisamchk. to repair or optimize tables, you _must_ always ensure that the *Note `mysqld': mysqld. server is not using the table (this also applies if external locking is disabled). If you do not stop *Note `mysqld': mysqld, you should at least do a *Note `mysqladmin flush-tables': mysqladmin. before you run *Note `myisamchk': myisamchk. Your tables _may become corrupted_ if the server and *Note `myisamchk': myisamchk. access the tables simultaneously. When performing crash recovery, it is important to understand that each `MyISAM' table TBL_NAME in a database corresponds to the three files in the database directory shown in the following table. File Purpose `TBL_NAME.frm' Definition (format) file `TBL_NAME.MYD' Data file `TBL_NAME.MYI' Index file Each of these three file types is subject to corruption in various ways, but problems occur most often in data files and index files. *Note `myisamchk': myisamchk. works by creating a copy of the `.MYD' data file row by row. It ends the repair stage by removing the old `.MYD' file and renaming the new file to the original file name. If you use `--quick', *Note `myisamchk': myisamchk. does not create a temporary `.MYD' file, but instead assumes that the `.MYD' file is correct and generates only a new index file without touching the `.MYD' file. This is safe, because *Note `myisamchk': myisamchk. automatically detects whether the `.MYD' file is corrupt and aborts the repair if it is. You can also specify the `--quick' option twice to *Note `myisamchk': myisamchk. In this case, *Note `myisamchk': myisamchk. does not abort on some errors (such as duplicate-key errors) but instead tries to resolve them by modifying the `.MYD' file. Normally the use of two `--quick' options is useful only if you have too little free disk space to perform a normal repair. In this case, you should at least make a backup of the table before running *Note `myisamchk': myisamchk.  File: manual.info, Node: myisam-check, Next: myisam-repair, Prev: myisam-crash-recovery, Up: myisam-table-maintenance 7.6.2 How to Check `MyISAM' Tables for Errors --------------------------------------------- To check a `MyISAM' table, use the following commands: * *Note `myisamchk TBL_NAME': myisamchk. This finds 99.99% of all errors. What it cannot find is corruption that involves _only_ the data file (which is very unusual). If you want to check a table, you should normally run *Note `myisamchk': myisamchk. without options or with the `-s' (silent) option. * *Note `myisamchk -m TBL_NAME': myisamchk. This finds 99.999% of all errors. It first checks all index entries for errors and then reads through all rows. It calculates a checksum for all key values in the rows and verifies that the checksum matches the checksum for the keys in the index tree. * *Note `myisamchk -e TBL_NAME': myisamchk. This does a complete and thorough check of all data (`-e' means `extended check'). It does a check-read of every key for each row to verify that they indeed point to the correct row. This may take a long time for a large table that has many indexes. Normally, *Note `myisamchk': myisamchk. stops after the first error it finds. If you want to obtain more information, you can add the `-v' (verbose) option. This causes *Note `myisamchk': myisamchk. to keep going, up through a maximum of 20 errors. * *Note `myisamchk -e -i TBL_NAME': myisamchk. This is like the previous command, but the `-i' option tells *Note `myisamchk': myisamchk. to print additional statistical information. In most cases, a simple *Note `myisamchk': myisamchk. command with no arguments other than the table name is sufficient to check a table.  File: manual.info, Node: myisam-repair, Next: myisam-optimization, Prev: myisam-check, Up: myisam-table-maintenance 7.6.3 How to Repair `MyISAM' Tables ----------------------------------- The discussion in this section describes how to use *Note `myisamchk': myisamchk. on `MyISAM' tables (extensions `.MYI' and `.MYD'). You can also use the *Note `CHECK TABLE': check-table. and *Note `REPAIR TABLE': repair-table. statements to check and repair `MyISAM' tables. See *Note check-table::, and *Note repair-table::. Symptoms of corrupted tables include queries that abort unexpectedly and observable errors such as these: * `TBL_NAME.frm' is locked against change * Can't find file `TBL_NAME.MYI' (Errcode: NNN) * Unexpected end of file * Record file is crashed * Got error NNN from table handler To get more information about the error, run *Note `perror': perror. NNN, where NNN is the error number. The following example shows how to use *Note `perror': perror. to find the meanings for the most common error numbers that indicate a problem with a table: shell> perror 126 127 132 134 135 136 141 144 145 MySQL error code 126 = Index file is crashed MySQL error code 127 = Record-file is crashed MySQL error code 132 = Old database file MySQL error code 134 = Record was already deleted (or record file crashed) MySQL error code 135 = No more room in record file MySQL error code 136 = No more room in index file MySQL error code 141 = Duplicate unique key or constraint on write or update MySQL error code 144 = Table is crashed and last repair failed MySQL error code 145 = Table was marked as crashed and should be repaired Note that error 135 (no more room in record file) and error 136 (no more room in index file) are not errors that can be fixed by a simple repair. In this case, you must use *Note `ALTER TABLE': alter-table. to increase the `MAX_ROWS' and `AVG_ROW_LENGTH' table option values: ALTER TABLE TBL_NAME MAX_ROWS=XXX AVG_ROW_LENGTH=YYY; If you do not know the current table option values, use *Note `SHOW CREATE TABLE': show-create-table. For the other errors, you must repair your tables. *Note `myisamchk': myisamchk. can usually detect and fix most problems that occur. The repair process involves up to four stages, described here. Before you begin, you should change location to the database directory and check the permissions of the table files. On Unix, make sure that they are readable by the user that *Note `mysqld': mysqld. runs as (and to you, because you need to access the files you are checking). If it turns out you need to modify files, they must also be writable by you. This section is for the cases where a table check fails (such as those described in *Note myisam-check::), or you want to use the extended features that *Note `myisamchk': myisamchk. provides. The *Note `myisamchk': myisamchk. options used for table maintenance with are described in *Note myisamchk::. *Note `myisamchk': myisamchk. also has variables that you can set to control memory allocation that may improve performance. See *Note myisamchk-memory::. If you are going to repair a table from the command line, you must first stop the *Note `mysqld': mysqld. server. Note that when you do *Note `mysqladmin shutdown': mysqladmin. on a remote server, the *Note `mysqld': mysqld. server is still available for a while after *Note `mysqladmin': mysqladmin. returns, until all statement-processing has stopped and all index changes have been flushed to disk. *Stage 1: Checking your tables* Run *Note `myisamchk *.MYI': myisamchk. or *Note `myisamchk -e *.MYI': myisamchk. if you have more time. Use the `-s' (silent) option to suppress unnecessary information. If the *Note `mysqld': mysqld. server is stopped, you should use the `--update-state' option to tell *Note `myisamchk': myisamchk. to mark the table as `checked.' You have to repair only those tables for which *Note `myisamchk': myisamchk. announces an error. For such tables, proceed to Stage 2. If you get unexpected errors when checking (such as `out of memory' errors), or if *Note `myisamchk': myisamchk. crashes, go to Stage 3. *Stage 2: Easy safe repair* First, try *Note `myisamchk -r -q TBL_NAME': myisamchk. (`-r -q' means `quick recovery mode'). This attempts to repair the index file without touching the data file. If the data file contains everything that it should and the delete links point at the correct locations within the data file, this should work, and the table is fixed. Start repairing the next table. Otherwise, use the following procedure: 1. Make a backup of the data file before continuing. 2. Use *Note `myisamchk -r TBL_NAME': myisamchk. (`-r' means `recovery mode'). This removes incorrect rows and deleted rows from the data file and reconstructs the index file. 3. If the preceding step fails, use *Note `myisamchk --safe-recover TBL_NAME': myisamchk. Safe recovery mode uses an old recovery method that handles a few cases that regular recovery mode does not (but is slower). *Note*: If you want a repair operation to go much faster, you should set the values of the `sort_buffer_size' and `key_buffer_size' variables each to about 25% of your available memory when running *Note `myisamchk': myisamchk. If you get unexpected errors when repairing (such as `out of memory' errors), or if *Note `myisamchk': myisamchk. crashes, go to Stage 3. *Stage 3: Difficult repair* You should reach this stage only if the first 16KB block in the index file is destroyed or contains incorrect information, or if the index file is missing. In this case, it is necessary to create a new index file. Do so as follows: 1. Move the data file to a safe place. 2. Use the table description file to create new (empty) data and index files: shell> mysql DB_NAME mysql> SET autocommit=1; mysql> TRUNCATE TABLE TBL_NAME; mysql> quit 3. Copy the old data file back onto the newly created data file. (Do not just move the old file back onto the new file. You want to retain a copy in case something goes wrong.) *Important*: If you are using replication, you should stop it prior to performing the above procedure, since it involves file system operations, and these are not logged by MySQL. Go back to Stage 2. *Note `myisamchk -r -q': myisamchk. should work. (This should not be an endless loop.) You can also use the `REPAIR TABLE TBL_NAME USE_FRM' SQL statement, which performs the whole procedure automatically. There is also no possibility of unwanted interaction between a utility and the server, because the server does all the work when you use *Note `REPAIR TABLE': repair-table. See *Note repair-table::. *Stage 4: Very difficult repair* You should reach this stage only if the `.frm' description file has also crashed. That should never happen, because the description file is not changed after the table is created: 1. Restore the description file from a backup and go back to Stage 3. You can also restore the index file and go back to Stage 2. In the latter case, you should start with *Note `myisamchk -r': myisamchk. 2. If you do not have a backup but know exactly how the table was created, create a copy of the table in another database. Remove the new data file, and then move the `.frm' description and `.MYI' index files from the other database to your crashed database. This gives you new description and index files, but leaves the `.MYD' data file alone. Go back to Stage 2 and attempt to reconstruct the index file.  File: manual.info, Node: myisam-optimization, Next: myisam-maintenance-schedule, Prev: myisam-repair, Up: myisam-table-maintenance 7.6.4 `MyISAM' Table Optimization --------------------------------- To coalesce fragmented rows and eliminate wasted space that results from deleting or updating rows, run *Note `myisamchk': myisamchk. in recovery mode: shell> myisamchk -r TBL_NAME You can optimize a table in the same way by using the *Note `OPTIMIZE TABLE': optimize-table. SQL statement. *Note `OPTIMIZE TABLE': optimize-table. does a table repair and a key analysis, and also sorts the index tree so that key lookups are faster. There is also no possibility of unwanted interaction between a utility and the server, because the server does all the work when you use *Note `OPTIMIZE TABLE': optimize-table. See *Note optimize-table::. *Note `myisamchk': myisamchk. has a number of other options that you can use to improve the performance of a table: * `--analyze' or `-a': Perform key distribution analysis. This improves join performance by enabling the join optimizer to better choose the order in which to join the tables and which indexes it should use. * `--sort-index' or `-S': Sort the index blocks. This optimizes seeks and makes table scans that use indexes faster. * `--sort-records=INDEX_NUM' or `-R INDEX_NUM': Sort data rows according to a given index. This makes your data much more localized and may speed up range-based *Note `SELECT': select. and `ORDER BY' operations that use this index. For a full description of all available options, see *Note myisamchk::.  File: manual.info, Node: myisam-maintenance-schedule, Prev: myisam-optimization, Up: myisam-table-maintenance 7.6.5 Setting Up a `MyISAM' Table Maintenance Schedule ------------------------------------------------------ It is a good idea to perform table checks on a regular basis rather than waiting for problems to occur. One way to check and repair `MyISAM' tables is with the *Note `CHECK TABLE': check-table. and *Note `REPAIR TABLE': repair-table. statements. See *Note table-maintenance-sql::. Another way to check tables is to use *Note `myisamchk': myisamchk. For maintenance purposes, you can use *Note `myisamchk -s': myisamchk. The `-s' option (short for `--silent') causes *Note `myisamchk': myisamchk. to run in silent mode, printing messages only when errors occur. It is also a good idea to enable automatic `MyISAM' table checking. For example, whenever the machine has done a restart in the middle of an update, you usually need to check each table that could have been affected before it is used further. (These are `expected crashed tables.') To cause the server to check `MyISAM' tables automatically, start it with the `--myisam-recover' option. See *Note server-options::. You should also check your tables regularly during normal system operation. For example, you can run a `cron' job to check important tables once a week, using a line like this in a `crontab' file: 35 0 * * 0 /PATH/TO/MYISAMCHK --fast --silent /PATH/TO/DATADIR/*/*.MYI This prints out information about crashed tables so that you can examine and repair them as necessary. To start with, execute *Note `myisamchk -s': myisamchk. each night on all tables that have been updated during the last 24 hours. As you see that problems occur infrequently, you can back off the checking frequency to once a week or so. Normally, MySQL tables need little maintenance. If you are performing many updates to `MyISAM' tables with dynamic-sized rows (tables with *Note `VARCHAR': char, *Note `BLOB': blob, or *Note `TEXT': blob. columns) or have tables with many deleted rows you may want to defragment/reclaim space from the tables from time to time. You can do this by using *Note `OPTIMIZE TABLE': optimize-table. on the tables in question. Alternatively, if you can stop the *Note `mysqld': mysqld. server for a while, change location into the data directory and use this command while the server is stopped: shell> myisamchk -r -s --sort-index --sort_buffer_size=16M */*.MYI  File: manual.info, Node: optimization, Next: language-structure, Prev: backup-and-recovery, Up: Top 8 Optimization ************** * Menu: * optimize-overview:: Optimization Overview * execution-plan-information:: Obtaining Query Execution Plan Information * statement-optimization:: Optimizing SQL Statements * controlling-optimizer:: Controlling the Query Optimizer * optimization-indexes:: Optimization and Indexes * buffering-caching:: Buffering and Caching * locking-issues:: Locking Issues * optimizing-database-structure:: Optimizing Database Structure * optimizing-the-server:: Optimizing the MySQL Server * thread-information:: Examining Thread Information This chapter explains different ways to optimize MySQL and provides examples. Optimization is a complex task because ultimately it requires understanding of the entire system to be optimized. Although it may be possible to perform some local optimizations with little knowledge of your system or application, the more optimal you want your system to become, the more you must know about it.  File: manual.info, Node: optimize-overview, Next: execution-plan-information, Prev: optimization, Up: optimization 8.1 Optimization Overview ========================= * Menu: * design-limitations:: MySQL Design Limitations and Tradeoffs * portability:: Designing Applications for Portability * mysql-benchmarks:: The MySQL Benchmark Suite * custom-benchmarks:: Using Your Own Benchmarks The most important factor in making a system fast is its basic design. You must also know what kinds of processing your system is doing, and what its bottlenecks are. In most cases, system bottlenecks arise from these sources: * Disk seeks. It takes time for the disk to find a piece of data. With modern disks, the mean time for this is usually lower than 10ms, so we can in theory do about 100 seeks a second. This time improves slowly with new disks and is very hard to optimize for a single table. The way to optimize seek time is to distribute the data onto more than one disk. * Disk reading and writing. When the disk is at the correct position, we need to read the data. With modern disks, one disk delivers at least 10-20MB/s throughput. This is easier to optimize than seeks because you can read in parallel from multiple disks. * CPU cycles. When we have the data in main memory, we need to process it to get our result. Having small tables compared to the amount of memory is the most common limiting factor. But with small tables, speed is usually not the problem. * Memory bandwidth. When the CPU needs more data than can fit in the CPU cache, main memory bandwidth becomes a bottleneck. This is an uncommon bottleneck for most systems, but one to be aware of.  File: manual.info, Node: design-limitations, Next: portability, Prev: optimize-overview, Up: optimize-overview 8.1.1 MySQL Design Limitations and Tradeoffs -------------------------------------------- When using the `MyISAM' storage engine, MySQL uses extremely fast table locking that permits multiple readers or a single writer. The biggest problem with this storage engine occurs when you have a steady stream of mixed updates and slow selects on a single table. If this is a problem for certain tables, you can use another storage engine for them. See *Note storage-engines::. MySQL can work with both transactional and nontransactional tables. To make it easier to work smoothly with nontransactional tables (which cannot roll back if something goes wrong), MySQL has the following rules. Note that these rules apply _only_ when not running in strict SQL mode or if you use the `IGNORE' specifier for *Note `INSERT': insert. or *Note `UPDATE': update. * All columns have default values. * If you insert an inappropriate or out-of-range value into a column, MySQL sets the column to the `best possible value' instead of reporting an error. For numeric values, this is 0, the smallest possible value or the largest possible value. For strings, this is either the empty string or as much of the string as can be stored in the column. * All calculated expressions return a value that can be used instead of signaling an error condition. For example, 1/0 returns `NULL'. To change the preceding behaviors, you can enable stricter data handling by setting the server SQL mode appropriately. For more information about data handling, see *Note constraints::, *Note server-sql-mode::, and *Note insert::.  File: manual.info, Node: portability, Next: mysql-benchmarks, Prev: design-limitations, Up: optimize-overview 8.1.2 Designing Applications for Portability -------------------------------------------- Because all SQL servers implement different parts of standard SQL, it takes work to write portable database applications. It is very easy to achieve portability for very simple selects and inserts, but becomes more difficult the more capabilities you require. If you want an application that is fast with many database systems, it becomes even more difficult. All database systems have some weak points. That is, they have different design compromises that lead to different behavior. To make a complex application portable, you need to determine which SQL servers it must work with, and then determine what features those servers support. You can use the MySQL `crash-me' program to find functions, types, and limits that you can use with a selection of database servers. `crash-me' does not check for every possible feature, but it is still reasonably comprehensive, performing about 450 tests. An example of the type of information `crash-me' can provide is that you should not use column names that are longer than 18 characters if you want to be able to use Informix or DB2. The `crash-me' program and the MySQL benchmarks are all very database independent. By taking a look at how they are written, you can get a feeling for what you must do to make your own applications database independent. The programs can be found in the `sql-bench' directory of MySQL source distributions. They are written in Perl and use the DBI database interface. Use of DBI in itself solves part of the portability problem because it provides database-independent access methods. See *Note mysql-benchmarks::. If you strive for database independence, you need to get a good feeling for each SQL server's bottlenecks. For example, MySQL is very fast in retrieving and updating rows for `MyISAM' tables, but has a problem in mixing slow readers and writers on the same table. Transactional database systems in general are not very good at generating summary tables from log tables, because in this case row locking is almost useless. To make your application _really_ database independent, you should define an easily extendable interface through which you manipulate your data. For example, C++ is available on most systems, so it makes sense to use a C++ class-based interface to the databases. If you use some feature that is specific to a given database system (such as the *Note `REPLACE': replace. statement, which is specific to MySQL), you should implement the same feature for other SQL servers by coding an alternative method. Although the alternative might be slower, it enables the other servers to perform the same tasks. With MySQL, you can use the `/*! */' syntax to add MySQL-specific keywords to a statement. The code inside `/* */' is treated as a comment (and ignored) by most other SQL servers. For information about writing comments, see *Note comments::. If high performance is more important than exactness, as for some Web applications, it is possible to create an application layer that caches all results to give you even higher performance. By letting old results expire after a while, you can keep the cache reasonably fresh. This provides a method to handle high load spikes, in which case you can dynamically increase the cache size and set the expiration timeout higher until things get back to normal. In this case, the table creation information should contain information about the initial cache size and how often the table should normally be refreshed. An attractive alternative to implementing an application cache is to use the MySQL query cache. By enabling the query cache, the server handles the details of determining whether a query result can be reused. This simplifies your application. See *Note query-cache::.  File: manual.info, Node: mysql-benchmarks, Next: custom-benchmarks, Prev: portability, Up: optimize-overview 8.1.3 The MySQL Benchmark Suite ------------------------------- This benchmark suite is meant to tell any user what operations a given SQL implementation performs well or poorly. You can get a good idea for how the benchmarks work by looking at the code and results in the `sql-bench' directory in any MySQL source distribution. Note that this benchmark is single-threaded, so it measures the minimum time for the operations performed. We plan to add multi-threaded tests to the benchmark suite in the future. To use the benchmark suite, the following requirements must be satisfied: * The benchmark suite is provided with MySQL source distributions. You can either download a released distribution from `http://dev.mysql.com/downloads/', or use the current development source tree. (See *Note installing-development-tree::.) * The benchmark scripts are written in Perl and use the Perl DBI module to access database servers, so DBI must be installed. You also need the server-specific DBD drivers for each of the servers you want to test. For example, to test MySQL, PostgreSQL, and DB2, you must have the `DBD::mysql', `DBD::Pg', and `DBD::DB2' modules installed. See *Note perl-support::. After you obtain a MySQL source distribution, you can find the benchmark suite located in its `sql-bench' directory. To run the benchmark tests, build MySQL, and then change location into the `sql-bench' directory and execute the `run-all-tests' script: shell> cd sql-bench shell> perl run-all-tests --server=SERVER_NAME SERVER_NAME should be the name of one of the supported servers. To get a list of all options and supported servers, invoke this command: shell> perl run-all-tests --help The `crash-me' script also is located in the `sql-bench' directory. `crash-me' tries to determine what features a database system supports and what its capabilities and limitations are by actually running queries. For example, it determines: * What data types are supported * How many indexes are supported * What functions are supported * How big a query can be * How big a *Note `VARCHAR': char. column can be For more information about benchmark results, visit http://www.mysql.com/why-mysql/benchmarks/.  File: manual.info, Node: custom-benchmarks, Prev: mysql-benchmarks, Up: optimize-overview 8.1.4 Using Your Own Benchmarks ------------------------------- You should definitely benchmark your application and database to find out where the bottlenecks are. After fixing one bottleneck (or by replacing it with a `dummy' module), you can proceed to identify the next bottleneck. Even if the overall performance for your application currently is acceptable, you should at least make a plan for each bottleneck and decide how to solve it if someday you really need the extra performance. For examples of portable benchmark programs, look at those in the MySQL benchmark suite. See *Note mysql-benchmarks::. You can take any program from this suite and modify it for your own needs. By doing this, you can try different solutions to your problem and test which really is fastest for you. Another free benchmark suite is the Open Source Database Benchmark, available at `http://osdb.sourceforge.net/'. It is very common for a problem to occur only when the system is very heavily loaded. We have had many customers who contact us when they have a (tested) system in production and have encountered load problems. In most cases, performance problems turn out to be due to issues of basic database design (for example, table scans are not good under high load) or problems with the operating system or libraries. Most of the time, these problems would be much easier to fix if the systems were not already in production. To avoid problems like this, you should put some effort into benchmarking your whole application under the worst possible load: * The *Note `mysqlslap': mysqlslap. program can be helpful for simulating a high load produced by multiple clients issuing queries simultaneously. See *Note mysqlslap::. * You can also try benchmarking packages such as SysBench and DBT2, available at `http://sourceforge.net/projects/sysbench/', and `http://osdldbt.sourceforge.net/#dbt2'. These programs or packages can bring a system to its knees, so be sure to use them only on your development systems.  File: manual.info, Node: execution-plan-information, Next: statement-optimization, Prev: optimize-overview, Up: optimization 8.2 Obtaining Query Execution Plan Information ============================================== * Menu: * using-explain:: Optimizing Queries with `EXPLAIN' * explain-output:: `EXPLAIN' Output Format * estimating-performance:: Estimating Query Performance  File: manual.info, Node: using-explain, Next: explain-output, Prev: execution-plan-information, Up: execution-plan-information 8.2.1 Optimizing Queries with `EXPLAIN' --------------------------------------- The *Note `EXPLAIN': explain. statement can be used either as a way to obtain information about how MySQL executes a *Note `SELECT': select. statement or as a synonym for *Note `DESCRIBE': describe.: * When you precede a *Note `SELECT': select. statement with the keyword *Note `EXPLAIN': explain, MySQL displays information from the optimizer about the query execution plan. That is, MySQL explains how it would process the *Note `SELECT': select, including information about how tables are joined and in which order. *Note `EXPLAIN EXTENDED': explain. can be used to provide additional information. The following sections describe how to use *Note `EXPLAIN': explain. and *Note `EXPLAIN EXTENDED': explain. to obtain query execution plan information. * *Note `EXPLAIN PARTITIONS': explain. is available beginning with MySQL 5.1.5. It is useful only when examining queries involving partitioned tables. For details, see *Note partitioning-info::. * *Note `EXPLAIN TBL_NAME': explain. is synonymous with `DESCRIBE TBL_NAME' or `SHOW COLUMNS FROM TBL_NAME'. For a description of the *Note `DESCRIBE': describe. and *Note `SHOW COLUMNS': show-columns. statements, see *Note describe::, and *Note show-columns::. With the help of *Note `EXPLAIN': explain, you can see where you should add indexes to tables to get a faster *Note `SELECT': select. that uses indexes to find rows. You can also use *Note `EXPLAIN': explain. to check whether the optimizer joins the tables in an optimal order. To give a hint to the optimizer to use a join order corresponding to the order in which the tables are named in the *Note `SELECT': select. statement, begin the statement with `SELECT STRAIGHT_JOIN' rather than just *Note `SELECT': select. (See *Note select::.) If you have a problem with indexes not being used when you believe that they should be, you should run *Note `ANALYZE TABLE': analyze-table. to update table statistics such as cardinality of keys, that can affect the choices the optimizer makes. See *Note analyze-table::.  File: manual.info, Node: explain-output, Next: estimating-performance, Prev: using-explain, Up: execution-plan-information 8.2.2 `EXPLAIN' Output Format ----------------------------- *Note `EXPLAIN': explain. returns a row of information for each table used in the *Note `SELECT': select. statement. The tables are listed in the output in the order that MySQL would read them while processing the query. MySQL resolves all joins using a nested-loop join method. This means that MySQL reads a row from the first table, and then finds a matching row in the second table, the third table, and so on. When all tables are processed, MySQL outputs the selected columns and backtracks through the table list until a table is found for which there are more matching rows. The next row is read from this table and the process continues with the next table. When the `EXTENDED' keyword is used, *Note `EXPLAIN': explain. produces extra information that can be viewed by issuing a *Note `SHOW WARNINGS': show-warnings. statement following the *Note `EXPLAIN': explain. statement. This information displays how the optimizer qualifies table and column names in the *Note `SELECT': select. statement, what the *Note `SELECT': select. looks like after the application of rewriting and optimization rules, and possibly other notes about the optimization process. *Note `EXPLAIN EXTENDED': explain. also displays the `filtered' column as of MySQL 5.1.12. *Note*: You cannot use the `EXTENDED' and `PARTITIONS' keywords together in the same *Note `EXPLAIN': explain. statement. Each output row from *Note `EXPLAIN': explain. provides information about one table, and each row contains the following columns: * `id' The *Note `SELECT': select. identifier. This is the sequential number of the *Note `SELECT': select. within the query. * `select_type' The type of *Note `SELECT': select, which can be any of those shown in the following table. `select_type' Meaning Value `SIMPLE' Simple *Note `SELECT': select. (not using *Note `UNION': union. or subqueries) `PRIMARY' Outermost *Note `SELECT': select. *Note `UNION': Second or later *Note `SELECT': select. statement union. in a *Note `UNION': union. `DEPENDENT UNION' Second or later *Note `SELECT': select. statement in a *Note `UNION': union, dependent on outer query `UNION RESULT' Result of a *Note `UNION': union. `SUBQUERY' First *Note `SELECT': select. in subquery `DEPENDENT First *Note `SELECT': select. in subquery, SUBQUERY' dependent on outer query `DERIVED' Derived table *Note `SELECT': select. (subquery in `FROM' clause) `UNCACHEABLE A subquery for which the result cannot be cached SUBQUERY' and must be re-evaluated for each row of the outer query `UNCACHEABLE The second or later select in a *Note `UNION': UNION' union. that belongs to an uncacheable subquery (see `UNCACHEABLE SUBQUERY') `DEPENDENT' typically signifies the use of a correlated subquery. See *Note correlated-subqueries::. `DEPENDENT SUBQUERY' evaluation differs from `UNCACHEABLE SUBQUERY' evaluation. For `DEPENDENT SUBQUERY', the subquery is re-evaluated only once for each set of different values of the variables from its outer context. For `UNCACHEABLE SUBQUERY', the subquery is re-evaluated for each row of the outer context. Cacheability of subqueries is subject to the restrictions detailed in *Note query-cache-operation::. For example, referring to user variables makes a subquery uncacheable. * `table' The table to which the row of output refers. * `type' The join type. The different join types are listed here, ordered from the best type to the worst: * `system' The table has only one row (= system table). This is a special case of the `const' join type. * `const' The table has at most one matching row, which is read at the start of the query. Because there is only one row, values from the column in this row can be regarded as constants by the rest of the optimizer. `const' tables are very fast because they are read only once. `const' is used when you compare all parts of a `PRIMARY KEY' or `UNIQUE' index to constant values. In the following queries, TBL_NAME can be used as a `const' table: SELECT * FROM TBL_NAME WHERE PRIMARY_KEY=1; SELECT * FROM TBL_NAME WHERE PRIMARY_KEY_PART1=1 AND PRIMARY_KEY_PART2=2; * `eq_ref' One row is read from this table for each combination of rows from the previous tables. Other than the `system' and `const' types, this is the best possible join type. It is used when all parts of an index are used by the join and the index is a `PRIMARY KEY' or `UNIQUE NOT NULL' index. `eq_ref' can be used for indexed columns that are compared using the `=' operator. The comparison value can be a constant or an expression that uses columns from tables that are read before this table. In the following examples, MySQL can use an `eq_ref' join to process REF_TABLE: SELECT * FROM REF_TABLE,OTHER_TABLE WHERE REF_TABLE.KEY_COLUMN=OTHER_TABLE.COLUMN; SELECT * FROM REF_TABLE,OTHER_TABLE WHERE REF_TABLE.KEY_COLUMN_PART1=OTHER_TABLE.COLUMN AND REF_TABLE.KEY_COLUMN_PART2=1; * `ref' All rows with matching index values are read from this table for each combination of rows from the previous tables. `ref' is used if the join uses only a leftmost prefix of the key or if the key is not a `PRIMARY KEY' or `UNIQUE' index (in other words, if the join cannot select a single row based on the key value). If the key that is used matches only a few rows, this is a good join type. `ref' can be used for indexed columns that are compared using the `=' or `<=>' operator. In the following examples, MySQL can use a `ref' join to process REF_TABLE: SELECT * FROM REF_TABLE WHERE KEY_COLUMN=EXPR; SELECT * FROM REF_TABLE,OTHER_TABLE WHERE REF_TABLE.KEY_COLUMN=OTHER_TABLE.COLUMN; SELECT * FROM REF_TABLE,OTHER_TABLE WHERE REF_TABLE.KEY_COLUMN_PART1=OTHER_TABLE.COLUMN AND REF_TABLE.KEY_COLUMN_PART2=1; * `fulltext' The join is performed using a `FULLTEXT' index. * `ref_or_null' This join type is like `ref', but with the addition that MySQL does an extra search for rows that contain `NULL' values. This join type optimization is used most often in resolving subqueries. In the following examples, MySQL can use a `ref_or_null' join to process REF_TABLE: SELECT * FROM REF_TABLE WHERE KEY_COLUMN=EXPR OR KEY_COLUMN IS NULL; See *Note is-null-optimization::. * `index_merge' This join type indicates that the Index Merge optimization is used. In this case, the `key' column in the output row contains a list of indexes used, and `key_len' contains a list of the longest key parts for the indexes used. For more information, see *Note index-merge-optimization::. * `unique_subquery' This type replaces `ref' for some `IN' subqueries of the following form: VALUE IN (SELECT PRIMARY_KEY FROM SINGLE_TABLE WHERE SOME_EXPR) `unique_subquery' is just an index lookup function that replaces the subquery completely for better efficiency. * `index_subquery' This join type is similar to `unique_subquery'. It replaces `IN' subqueries, but it works for nonunique indexes in subqueries of the following form: VALUE IN (SELECT KEY_COLUMN FROM SINGLE_TABLE WHERE SOME_EXPR) * `range' Only rows that are in a given range are retrieved, using an index to select the rows. The `key' column in the output row indicates which index is used. The `key_len' contains the longest key part that was used. The `ref' column is `NULL' for this type. `range' can be used when a key column is compared to a constant using any of the `=', `<>', `>', `>=', `<', `<=', `IS NULL', `<=>', `BETWEEN', or `IN()' operators: SELECT * FROM TBL_NAME WHERE KEY_COLUMN = 10; SELECT * FROM TBL_NAME WHERE KEY_COLUMN BETWEEN 10 and 20; SELECT * FROM TBL_NAME WHERE KEY_COLUMN IN (10,20,30); SELECT * FROM TBL_NAME WHERE KEY_PART1= 10 AND KEY_PART2 IN (10,20,30); * `index' This join type is the same as `ALL', except that only the index tree is scanned. This usually is faster than `ALL' because the index file usually is smaller than the data file. MySQL can use this join type when the query uses only columns that are part of a single index. * `ALL' A full table scan is done for each combination of rows from the previous tables. This is normally not good if the table is the first table not marked `const', and usually _very_ bad in all other cases. Normally, you can avoid `ALL' by adding indexes that enable row retrieval from the table based on constant values or column values from earlier tables. * `possible_keys' The `possible_keys' column indicates which indexes MySQL can choose from use to find the rows in this table. Note that this column is totally independent of the order of the tables as displayed in the output from *Note `EXPLAIN': explain. That means that some of the keys in `possible_keys' might not be usable in practice with the generated table order. If this column is `NULL', there are no relevant indexes. In this case, you may be able to improve the performance of your query by examining the `WHERE' clause to check whether it refers to some column or columns that would be suitable for indexing. If so, create an appropriate index and check the query with *Note `EXPLAIN': explain. again. See *Note alter-table::. To see what indexes a table has, use `SHOW INDEX FROM TBL_NAME'. * `key' The `key' column indicates the key (index) that MySQL actually decided to use. If MySQL decides to use one of the `possible_keys' indexes to look up rows, that index is listed as the key value. It is possible that `key' will name an index that is not present in the `possible_keys' value. This can happen if none of the `possible_keys' indexes are suitable for looking up rows, but all the columns selected by the query are columns of some other index. That is, the named index covers the selected columns, so although it is not used to determine which rows to retrieve, an index scan is more efficient than a data row scan. For `InnoDB', a secondary index might cover the selected columns even if the query also selects the primary key because `InnoDB' stores the primary key value with each secondary index. If `key' is `NULL', MySQL found no index to use for executing the query more efficiently. To force MySQL to use or ignore an index listed in the `possible_keys' column, use `FORCE INDEX', `USE INDEX', or `IGNORE INDEX' in your query. See *Note index-hints::. For `MyISAM' tables, running *Note `ANALYZE TABLE': analyze-table. helps the optimizer choose better indexes. For `MyISAM' tables, *Note `myisamchk --analyze': myisamchk. does the same. See *Note analyze-table::, and *Note myisam-table-maintenance::. * `key_len' The `key_len' column indicates the length of the key that MySQL decided to use. The length is `NULL' if the `key' column says `NULL'. Note that the value of `key_len' enables you to determine how many parts of a multiple-part key MySQL actually uses. * `ref' The `ref' column shows which columns or constants are compared to the index named in the `key' column to select rows from the table. * `rows' The `rows' column indicates the number of rows MySQL believes it must examine to execute the query. For *Note `InnoDB': innodb-storage-engine. tables, this number is an estimate, and may not always be exact. * `filtered' The `filtered' column indicates an estimated percentage of table rows that will be filtered by the table condition. That is, `rows' shows the estimated number of rows examined and `rows' x `filtered' / `100' shows the number of rows that will be joined with previous tables. This column is displayed if you use *Note `EXPLAIN EXTENDED': explain. (New in MySQL 5.1.12) * `Extra' This column contains additional information about how MySQL resolves the query. The following list explains the values that can appear in this column. If you want to make your queries as fast as possible, you should look out for `Extra' values of `Using filesort' and `Using temporary'. * `Child of 'TABLE' pushed join@1' This table is referenced as the child of TABLE in a join that can be pushed down to the NDB kernel. Applies only in MySQL Cluster NDB 7.2.0 and later, when pushed-down joins are enabled. See the description of the `ndb_join_pushdown' server system variable for more information and examples. * `const row not found' For a query such as `SELECT ... FROM TBL_NAME', the table was empty. * `Distinct' MySQL is looking for distinct values, so it stops searching for more rows for the current row combination after it has found the first matching row. * `Full scan on NULL key' This occurs for subquery optimization as a fallback strategy when the optimizer cannot use an index-lookup access method. * `Impossible HAVING' The `HAVING' clause is always false and cannot select any rows. * `Impossible WHERE' The `WHERE' clause is always false and cannot select any rows. * `Impossible WHERE noticed after reading const tables' MySQL has read all `const' (and `system') tables and notice that the `WHERE' clause is always false. * `No matching min/max row' No row satisfies the condition for a query such as `SELECT MIN(...) FROM ... WHERE CONDITION'. * `no matching row in const table' For a query with a join, there was an empty table or a table with no rows satisfying a unique index condition. * `No tables used' The query has no `FROM' clause, or has a `FROM DUAL' clause. * `Not exists' MySQL was able to do a `LEFT JOIN' optimization on the query and does not examine more rows in this table for the previous row combination after it finds one row that matches the `LEFT JOIN' criteria. Here is an example of the type of query that can be optimized this way: SELECT * FROM t1 LEFT JOIN t2 ON t1.id=t2.id WHERE t2.id IS NULL; Assume that `t2.id' is defined as `NOT NULL'. In this case, MySQL scans `t1' and looks up the rows in `t2' using the values of `t1.id'. If MySQL finds a matching row in `t2', it knows that `t2.id' can never be `NULL', and does not scan through the rest of the rows in `t2' that have the same `id' value. In other words, for each row in `t1', MySQL needs to do only a single lookup in `t2', regardless of how many rows actually match in `t2'. * `Parent of N pushed join@1' This table is referenced as the parent of the table in row N of the current *Note `EXPLAIN': explain. output in a join that can be pushed down to the NDB kernel. Applies only in MySQL Cluster NDB 7.2.0 and later when pushed-down joins are enabled. See the description of the `ndb_join_pushdown' server system variable for more information and examples. * `Range checked for each record (index map: N)' MySQL found no good index to use, but found that some of indexes might be used after column values from preceding tables are known. For each row combination in the preceding tables, MySQL checks whether it is possible to use a `range' or `index_merge' access method to retrieve rows. This is not very fast, but is faster than performing a join with no index at all. The applicability criteria are as described in *Note range-optimization::, and *Note index-merge-optimization::, with the exception that all column values for the preceding table are known and considered to be constants. Indexes are numbered beginning with 1, in the same order as shown by *Note `SHOW INDEX': show-index. for the table. The index map value N is a bitmask value that indicates which indexes are candidates. For example, a value of `0x19' (binary 11001) means that indexes 1, 4, and 5 will be considered. * `Scanned N databases' This indicates how many directory scans the server performs when processing a query for `INFORMATION_SCHEMA' tables, as described in *Note information-schema-optimization::. The value of N can be 0, 1, or `all'. * `Select tables optimized away' The query contained only aggregate functions (`MIN()', `MAX()') that were all resolved using an index, or `COUNT(*)' for `MyISAM', and no `GROUP BY' clause. The optimizer determined that only one row should be returned. * `Skip_open_table', `Open_frm_only', `Open_trigger_only', `Open_full_table' These values indicate file-opening optimizations that apply to queries for `INFORMATION_SCHEMA' tables, as described in *Note information-schema-optimization::. * `Skip_open_table': Table files do not need to be opened. The information has already become available within the query by scanning the database directory. * `Open_frm_only': Only the table's `.frm' file need be opened. * `Open_trigger_only': Only the table's `.TRG' file need be opened. * `Open_full_table': The unoptimized information lookup. The `.frm', `.MYD', and `.MYI' files must be opened. * `unique row not found' For a query such as `SELECT ... FROM TBL_NAME', no rows satisfy the condition for a `UNIQUE' index or `PRIMARY KEY' on the table. * `Using filesort' MySQL must do an extra pass to find out how to retrieve the rows in sorted order. The sort is done by going through all rows according to the join type and storing the sort key and pointer to the row for all rows that match the `WHERE' clause. The keys then are sorted and the rows are retrieved in sorted order. See *Note order-by-optimization::. * `Using index' The column information is retrieved from the table using only information in the index tree without having to do an additional seek to read the actual row. This strategy can be used when the query uses only columns that are part of a single index. For `InnoDB' tables that have a user-defined clustered index, that index can be used even when `Using index' is absent from the `Extra' column. This is the case if `type' is `index' and `key' is `PRIMARY'. * `Using index for group-by' Similar to the `Using index' table access method, `Using index for group-by' indicates that MySQL found an index that can be used to retrieve all columns of a `GROUP BY' or `DISTINCT' query without any extra disk access to the actual table. Additionally, the index is used in the most efficient way so that for each group, only a few index entries are read. For details, see *Note group-by-optimization::. * `Using join buffer' Tables from earlier joins are read in portions into the join buffer, and then their rows are used from the buffer to perform the join with the current table. * `Using sort_union(...)', `Using union(...)', `Using intersect(...)' These indicate how index scans are merged for the `index_merge' join type. See *Note index-merge-optimization::. * `Using temporary' To resolve the query, MySQL needs to create a temporary table to hold the result. This typically happens if the query contains `GROUP BY' and `ORDER BY' clauses that list columns differently. * `Using where' A `WHERE' clause is used to restrict which rows to match against the next table or send to the client. Unless you specifically intend to fetch or examine all rows from the table, you may have something wrong in your query if the `Extra' value is not `Using where' and the table join type is `ALL' or `index'. Even if you are using an index for all parts of a `WHERE' clause, you may see `Using where' if the column can be `NULL'. * `Using where with pushed condition' This item applies to *Note `NDBCLUSTER': mysql-cluster. tables _only_. It means that MySQL Cluster is using the Condition Pushdown optimization to improve the efficiency of a direct comparison between a nonindexed column and a constant. In such cases, the condition is `pushed down' to the cluster's data nodes and is evaluated on all data nodes simultaneously. This eliminates the need to send nonmatching rows over the network, and can speed up such queries by a factor of 5 to 10 times over cases where Condition Pushdown could be but is not used. For more information, see *Note condition-pushdown-optimization::. You can get a good indication of how good a join is by taking the product of the values in the `rows' column of the *Note `EXPLAIN': explain. output. This should tell you roughly how many rows MySQL must examine to execute the query. If you restrict queries with the `max_join_size' system variable, this row product also is used to determine which multiple-table *Note `SELECT': select. statements to execute and which to abort. See *Note server-parameters::. The following example shows how a multiple-table join can be optimized progressively based on the information provided by *Note `EXPLAIN': explain. Suppose that you have the *Note `SELECT': select. statement shown here and that you plan to examine it using *Note `EXPLAIN': explain.: EXPLAIN SELECT tt.TicketNumber, tt.TimeIn, tt.ProjectReference, tt.EstimatedShipDate, tt.ActualShipDate, tt.ClientID, tt.ServiceCodes, tt.RepetitiveID, tt.CurrentProcess, tt.CurrentDPPerson, tt.RecordVolume, tt.DPPrinted, et.COUNTRY, et_1.COUNTRY, do.CUSTNAME FROM tt, et, et AS et_1, do WHERE tt.SubmitTime IS NULL AND tt.ActualPC = et.EMPLOYID AND tt.AssignedPC = et_1.EMPLOYID AND tt.ClientID = do.CUSTNMBR; For this example, make the following assumptions: * The columns being compared have been declared as follows. Table Column Data Type `tt' `ActualPC' `CHAR(10)' `tt' `AssignedPC' `CHAR(10)' `tt' `ClientID' `CHAR(10)' `et' `EMPLOYID' `CHAR(15)' `do' `CUSTNMBR' `CHAR(15)' * The tables have the following indexes. Table Index `tt' `ActualPC' `tt' `AssignedPC' `tt' `ClientID' `et' `EMPLOYID' (primary key) `do' `CUSTNMBR' (primary key) * The `tt.ActualPC' values are not evenly distributed. Initially, before any optimizations have been performed, the *Note `EXPLAIN': explain. statement produces the following information: table type possible_keys key key_len ref rows Extra et ALL PRIMARY NULL NULL NULL 74 do ALL PRIMARY NULL NULL NULL 2135 et_1 ALL PRIMARY NULL NULL NULL 74 tt ALL AssignedPC, NULL NULL NULL 3872 ClientID, ActualPC Range checked for each record (index map: 0x23) Because `type' is `ALL' for each table, this output indicates that MySQL is generating a Cartesian product of all the tables; that is, every combination of rows. This takes quite a long time, because the product of the number of rows in each table must be examined. For the case at hand, this product is 74 x 2135 x 74 x 3872 = 45,268,558,720 rows. If the tables were bigger, you can only imagine how long it would take. One problem here is that MySQL can use indexes on columns more efficiently if they are declared as the same type and size. In this context, *Note `VARCHAR': char. and *Note `CHAR': char. are considered the same if they are declared as the same size. `tt.ActualPC' is declared as `CHAR(10)' and `et.EMPLOYID' is `CHAR(15)', so there is a length mismatch. To fix this disparity between column lengths, use *Note `ALTER TABLE': alter-table. to lengthen `ActualPC' from 10 characters to 15 characters: mysql> ALTER TABLE tt MODIFY ActualPC VARCHAR(15); Now `tt.ActualPC' and `et.EMPLOYID' are both `VARCHAR(15)'. Executing the *Note `EXPLAIN': explain. statement again produces this result: table type possible_keys key key_len ref rows Extra tt ALL AssignedPC, NULL NULL NULL 3872 Using ClientID, where ActualPC do ALL PRIMARY NULL NULL NULL 2135 Range checked for each record (index map: 0x1) et_1 ALL PRIMARY NULL NULL NULL 74 Range checked for each record (index map: 0x1) et eq_ref PRIMARY PRIMARY 15 tt.ActualPC 1 This is not perfect, but is much better: The product of the `rows' values is less by a factor of 74. This version executes in a couple of seconds. A second alteration can be made to eliminate the column length mismatches for the `tt.AssignedPC = et_1.EMPLOYID' and `tt.ClientID = do.CUSTNMBR' comparisons: mysql> ALTER TABLE tt MODIFY AssignedPC VARCHAR(15), -> MODIFY ClientID VARCHAR(15); After that modification, *Note `EXPLAIN': explain. produces the output shown here: table type possible_keys key key_len ref rows Extra et ALL PRIMARY NULL NULL NULL 74 tt ref AssignedPC, ActualPC 15 et.EMPLOYID 52 Using ClientID, where ActualPC et_1 eq_ref PRIMARY PRIMARY 15 tt.AssignedPC 1 do eq_ref PRIMARY PRIMARY 15 tt.ClientID 1 At this point, the query is optimized almost as well as possible. The remaining problem is that, by default, MySQL assumes that values in the `tt.ActualPC' column are evenly distributed, and that is not the case for the `tt' table. Fortunately, it is easy to tell MySQL to analyze the key distribution: mysql> ANALYZE TABLE tt; With the additional index information, the join is perfect and *Note `EXPLAIN': explain. produces this result: table type possible_keys key key_len ref rows Extra tt ALL AssignedPC NULL NULL NULL 3872 Using ClientID, where ActualPC et eq_ref PRIMARY PRIMARY 15 tt.ActualPC 1 et_1 eq_ref PRIMARY PRIMARY 15 tt.AssignedPC 1 do eq_ref PRIMARY PRIMARY 15 tt.ClientID 1 Note that the `rows' column in the output from *Note `EXPLAIN': explain. is an educated guess from the MySQL join optimizer. You should check whether the numbers are even close to the truth by comparing the `rows' product with the actual number of rows that the query returns. If the numbers are quite different, you might get better performance by using `STRAIGHT_JOIN' in your *Note `SELECT': select. statement and trying to list the tables in a different order in the `FROM' clause. It is possible in some cases to execute statements that modify data when *Note `EXPLAIN SELECT': explain. is used with a subquery; for more information, see *Note from-clause-subqueries::.  File: manual.info, Node: estimating-performance, Prev: explain-output, Up: execution-plan-information 8.2.3 Estimating Query Performance ---------------------------------- In most cases, you can estimate query performance by counting disk seeks. For small tables, you can usually find a row in one disk seek (because the index is probably cached). For bigger tables, you can estimate that, using B-tree indexes, you need this many seeks to find a row: `log(ROW_COUNT) / log(INDEX_BLOCK_LENGTH / 3 * 2 / (INDEX_LENGTH + DATA_POINTER_LENGTH)) + 1'. In MySQL, an index block is usually 1,024 bytes and the data pointer is usually four bytes. For a 500,000-row table with a key value length of three bytes (the size of *Note `MEDIUMINT': numeric-types.), the formula indicates `log(500,000)/log(1024/3*2/(3+4)) + 1' = `4' seeks. This index would require storage of about 500,000 * 7 * 3/2 = 5.2MB (assuming a typical index buffer fill ratio of 2/3), so you probably have much of the index in memory and so need only one or two calls to read data to find the row. For writes, however, you need four seek requests to find where to place a new index value and normally two seeks to update the index and write the row. Note that the preceding discussion does not mean that your application performance slowly degenerates by log N. As long as everything is cached by the OS or the MySQL server, things become only marginally slower as the table gets bigger. After the data gets too big to be cached, things start to go much slower until your applications are bound only by disk seeks (which increase by log N). To avoid this, increase the key cache size as the data grows. For `MyISAM' tables, the key cache size is controlled by the `key_buffer_size' system variable. See *Note server-parameters::.  File: manual.info, Node: statement-optimization, Next: controlling-optimizer, Prev: execution-plan-information, Up: optimization 8.3 Optimizing SQL Statements ============================= * Menu: * select-optimization:: Optimizing `SELECT' Statements * non-select-optimization:: Optimizing Non-`SELECT' Statements * information-schema-optimization:: `INFORMATION_SCHEMA' Optimization * miscellaneous-optimization-tips:: Other Optimization Tips  File: manual.info, Node: select-optimization, Next: non-select-optimization, Prev: statement-optimization, Up: statement-optimization 8.3.1 Optimizing `SELECT' Statements ------------------------------------ * Menu: * select-speed:: Speed of `SELECT' Statements * where-optimizations:: `WHERE' Clause Optimization * range-optimization:: Range Optimization * index-merge-optimization:: Index Merge Optimization * condition-pushdown-optimization:: Engine Condition Pushdown Optimization * is-null-optimization:: `IS NULL' Optimization * left-join-optimization:: `LEFT JOIN' and `RIGHT JOIN' Optimization * nested-loop-joins:: Nested-Loop Join Algorithms * nested-join-optimization:: Nested Join Optimization * outer-join-simplification:: Outer Join Simplification * order-by-optimization:: `ORDER BY' Optimization * group-by-optimization:: `GROUP BY' Optimization * distinct-optimization:: `DISTINCT' Optimization * in-subquery-optimization:: Optimizing `IN'/`=ANY' Subqueries * limit-optimization:: `LIMIT' Optimization * how-to-avoid-table-scan:: How to Avoid Table Scans First, one factor affects all statements: The more complex your permissions setup, the more overhead you have. Using simpler permissions when you issue *Note `GRANT': grant. statements enables MySQL to reduce permission-checking overhead when clients execute statements. For example, if you do not grant any table-level or column-level privileges, the server need not ever check the contents of the `tables_priv' and `columns_priv' tables. Similarly, if you place no resource limits on any accounts, the server does not have to perform resource counting. If you have a very high statement-processing load, it may be worth the time to use a simplified grant structure to reduce permission-checking overhead. If your problem is with a specific MySQL expression or function, you can perform a timing test by invoking the `BENCHMARK()' function using the *Note `mysql': mysql. client program. Its syntax is `BENCHMARK(LOOP_COUNT,EXPRESSION)'. The return value is always zero, but *Note `mysql': mysql. prints a line displaying approximately how long the statement took to execute. For example: mysql> SELECT BENCHMARK(1000000,1+1); +------------------------+ | BENCHMARK(1000000,1+1) | +------------------------+ | 0 | +------------------------+ 1 row in set (0.32 sec) This result was obtained on a Pentium II 400MHz system. It shows that MySQL can execute 1,000,000 simple addition expressions in 0.32 seconds on that system. All MySQL functions should be highly optimized, but there may be some exceptions. `BENCHMARK()' is an excellent tool for finding out if some function is a problem for your queries.  File: manual.info, Node: select-speed, Next: where-optimizations, Prev: select-optimization, Up: select-optimization 8.3.1.1 Speed of `SELECT' Statements .................................... In general, when you want to make a slow `SELECT ... WHERE' query faster, the first thing to check is whether you can add an index. All references between different tables should usually be done with indexes. You can use the *Note `EXPLAIN': explain. statement to determine which indexes are used for a *Note `SELECT': select. See *Note using-explain::, and *Note mysql-indexes::. Some general tips for speeding up queries on `MyISAM' tables: * To help MySQL better optimize queries, use *Note `ANALYZE TABLE': analyze-table. or run *Note `myisamchk --analyze': myisamchk. on a table after it has been loaded with data. This updates a value for each index part that indicates the average number of rows that have the same value. (For unique indexes, this is always 1.) MySQL uses this to decide which index to choose when you join two tables based on a nonconstant expression. You can check the result from the table analysis by using `SHOW INDEX FROM TBL_NAME' and examining the `Cardinality' value. *Note `myisamchk --description --verbose': myisamchk. shows index distribution information. * To sort an index and data according to an index, use *Note `myisamchk --sort-index --sort-records=1': myisamchk. (assuming that you want to sort on index 1). This is a good way to make queries faster if you have a unique index from which you want to read all rows in order according to the index. The first time you sort a large table this way, it may take a long time.  File: manual.info, Node: where-optimizations, Next: range-optimization, Prev: select-speed, Up: select-optimization 8.3.1.2 `WHERE' Clause Optimization ................................... This section discusses optimizations that can be made for processing `WHERE' clauses. The examples use *Note `SELECT': select. statements, but the same optimizations apply for `WHERE' clauses in *Note `DELETE': delete. and *Note `UPDATE': update. statements. Work on the MySQL optimizer is ongoing, so this section is incomplete. MySQL performs a great many optimizations, not all of which are documented here. Some of the optimizations performed by MySQL follow: * Removal of unnecessary parentheses: ((a AND b) AND c OR (((a AND b) AND (c AND d)))) -> (a AND b AND c) OR (a AND b AND c AND d) * Constant folding: (a b>5 AND b=c AND a=5 * Constant condition removal (needed because of constant folding): (B>=5 AND B=5) OR (B=6 AND 5=5) OR (B=7 AND 5=6) -> B=5 OR B=6 * Constant expressions used by indexes are evaluated only once. * `COUNT(*)' on a single table without a `WHERE' is retrieved directly from the table information for `MyISAM' and `MEMORY' tables. This is also done for any `NOT NULL' expression when used with only one table. * Early detection of invalid constant expressions. MySQL quickly detects that some *Note `SELECT': select. statements are impossible and returns no rows. * `HAVING' is merged with `WHERE' if you do not use `GROUP BY' or aggregate functions (`COUNT()', `MIN()', and so on). * For each table in a join, a simpler `WHERE' is constructed to get a fast `WHERE' evaluation for the table and also to skip rows as soon as possible. * All constant tables are read first before any other tables in the query. A constant table is any of the following: * An empty table or a table with one row. * A table that is used with a `WHERE' clause on a `PRIMARY KEY' or a `UNIQUE' index, where all index parts are compared to constant expressions and are defined as `NOT NULL'. All of the following tables are used as constant tables: SELECT * FROM t WHERE PRIMARY_KEY=1; SELECT * FROM t1,t2 WHERE t1.PRIMARY_KEY=1 AND t2.PRIMARY_KEY=t1.id; * The best join combination for joining the tables is found by trying all possibilities. If all columns in `ORDER BY' and `GROUP BY' clauses come from the same table, that table is preferred first when joining. * If there is an `ORDER BY' clause and a different `GROUP BY' clause, or if the `ORDER BY' or `GROUP BY' contains columns from tables other than the first table in the join queue, a temporary table is created. * If you use the `SQL_SMALL_RESULT' option, MySQL uses an in-memory temporary table. * Each table index is queried, and the best index is used unless the optimizer believes that it is more efficient to use a table scan. At one time, a scan was used based on whether the best index spanned more than 30% of the table, but a fixed percentage no longer determines the choice between using an index or a scan. The optimizer now is more complex and bases its estimate on additional factors such as table size, number of rows, and I/O block size. * In some cases, MySQL can read rows from the index without even consulting the data file. If all columns used from the index are numeric, only the index tree is used to resolve the query. * Before each row is output, those that do not match the `HAVING' clause are skipped. Some examples of queries that are very fast: SELECT COUNT(*) FROM TBL_NAME; SELECT MIN(KEY_PART1),MAX(KEY_PART1) FROM TBL_NAME; SELECT MAX(KEY_PART2) FROM TBL_NAME WHERE KEY_PART1=CONSTANT; SELECT ... FROM TBL_NAME ORDER BY KEY_PART1,KEY_PART2,... LIMIT 10; SELECT ... FROM TBL_NAME ORDER BY KEY_PART1 DESC, KEY_PART2 DESC, ... LIMIT 10; MySQL resolves the following queries using only the index tree, assuming that the indexed columns are numeric: SELECT KEY_PART1,KEY_PART2 FROM TBL_NAME WHERE KEY_PART1=VAL; SELECT COUNT(*) FROM TBL_NAME WHERE KEY_PART1=VAL1 AND KEY_PART2=VAL2; SELECT KEY_PART2 FROM TBL_NAME GROUP BY KEY_PART1; The following queries use indexing to retrieve the rows in sorted order without a separate sorting pass: SELECT ... FROM TBL_NAME ORDER BY KEY_PART1,KEY_PART2,... ; SELECT ... FROM TBL_NAME ORDER BY KEY_PART1 DESC, KEY_PART2 DESC, ... ;  File: manual.info, Node: range-optimization, Next: index-merge-optimization, Prev: where-optimizations, Up: select-optimization 8.3.1.3 Range Optimization .......................... * Menu: * range-access-single-part:: The Range Access Method for Single-Part Indexes * range-access-multi-part:: The Range Access Method for Multiple-Part Indexes The `range' access method uses a single index to retrieve a subset of table rows that are contained within one or several index value intervals. It can be used for a single-part or multiple-part index. The following sections give a detailed description of how intervals are extracted from the `WHERE' clause.  File: manual.info, Node: range-access-single-part, Next: range-access-multi-part, Prev: range-optimization, Up: range-optimization 8.3.1.4 The Range Access Method for Single-Part Indexes ....................................................... For a single-part index, index value intervals can be conveniently represented by corresponding conditions in the `WHERE' clause, so we speak of _range conditions_ rather than `intervals.' The definition of a range condition for a single-part index is as follows: * For both `BTREE' and `HASH' indexes, comparison of a key part with a constant value is a range condition when using the `=', `<=>', `IN()', `IS NULL', or `IS NOT NULL' operators. * Additionally, for `BTREE' indexes, comparison of a key part with a constant value is a range condition when using the `>', `<', `>=', `<=', `BETWEEN', `!=', or `<>' operators, or `LIKE' comparisons if the argument to `LIKE' is a constant string that does not start with a wildcard character. * For all types of indexes, multiple range conditions combined with `OR' or `AND' form a range condition. `Constant value' in the preceding descriptions means one of the following: * A constant from the query string * A column of a `const' or `system' table from the same join * The result of an uncorrelated subquery * Any expression composed entirely from subexpressions of the preceding types Here are some examples of queries with range conditions in the `WHERE' clause: SELECT * FROM t1 WHERE KEY_COL > 1 AND KEY_COL < 10; SELECT * FROM t1 WHERE KEY_COL = 1 OR KEY_COL IN (15,18,20); SELECT * FROM t1 WHERE KEY_COL LIKE 'ab%' OR KEY_COL BETWEEN 'bar' AND 'foo'; Note that some nonconstant values may be converted to constants during the constant propagation phase. MySQL tries to extract range conditions from the `WHERE' clause for each of the possible indexes. During the extraction process, conditions that cannot be used for constructing the range condition are dropped, conditions that produce overlapping ranges are combined, and conditions that produce empty ranges are removed. Consider the following statement, where `key1' is an indexed column and `nonkey' is not indexed: SELECT * FROM t1 WHERE (key1 < 'abc' AND (key1 LIKE 'abcde%' OR key1 LIKE '%b')) OR (key1 < 'bar' AND nonkey = 4) OR (key1 < 'uux' AND key1 > 'z'); The extraction process for key `key1' is as follows: 1. Start with original `WHERE' clause: (key1 < 'abc' AND (key1 LIKE 'abcde%' OR key1 LIKE '%b')) OR (key1 < 'bar' AND nonkey = 4) OR (key1 < 'uux' AND key1 > 'z') 2. Remove `nonkey = 4' and `key1 LIKE '%b'' because they cannot be used for a range scan. The correct way to remove them is to replace them with `TRUE', so that we do not miss any matching rows when doing the range scan. Having replaced them with `TRUE', we get: (key1 < 'abc' AND (key1 LIKE 'abcde%' OR TRUE)) OR (key1 < 'bar' AND TRUE) OR (key1 < 'uux' AND key1 > 'z') 3. Collapse conditions that are always true or false: * `(key1 LIKE 'abcde%' OR TRUE)' is always true * `(key1 < 'uux' AND key1 > 'z')' is always false Replacing these conditions with constants, we get: (key1 < 'abc' AND TRUE) OR (key1 < 'bar' AND TRUE) OR (FALSE) Removing unnecessary `TRUE' and `FALSE' constants, we obtain: (key1 < 'abc') OR (key1 < 'bar') 4. Combining overlapping intervals into one yields the final condition to be used for the range scan: (key1 < 'bar') In general (and as demonstrated by the preceding example), the condition used for a range scan is less restrictive than the `WHERE' clause. MySQL performs an additional check to filter out rows that satisfy the range condition but not the full `WHERE' clause. The range condition extraction algorithm can handle nested `AND'/`OR' constructs of arbitrary depth, and its output does not depend on the order in which conditions appear in `WHERE' clause. Currently, MySQL does not support merging multiple ranges for the `range' access method for spatial indexes. To work around this limitation, you can use a *Note `UNION': union. with identical *Note `SELECT': select. statements, except that you put each spatial predicate in a different *Note `SELECT': select.  File: manual.info, Node: range-access-multi-part, Prev: range-access-single-part, Up: range-optimization 8.3.1.5 The Range Access Method for Multiple-Part Indexes ......................................................... Range conditions on a multiple-part index are an extension of range conditions for a single-part index. A range condition on a multiple-part index restricts index rows to lie within one or several key tuple intervals. Key tuple intervals are defined over a set of key tuples, using ordering from the index. For example, consider a multiple-part index defined as `key1(KEY_PART1, KEY_PART2, KEY_PART3)', and the following set of key tuples listed in key order: KEY_PART1 KEY_PART2 KEY_PART3 NULL 1 'abc' NULL 1 'xyz' NULL 2 'foo' 1 1 'abc' 1 1 'xyz' 1 2 'abc' 2 1 'aaa' The condition `KEY_PART1 = 1' defines this interval: (1,-inf,-inf) <= (KEY_PART1,KEY_PART2,KEY_PART3) < (1,+inf,+inf) The interval covers the 4th, 5th, and 6th tuples in the preceding data set and can be used by the range access method. By contrast, the condition `KEY_PART3 = 'abc'' does not define a single interval and cannot be used by the range access method. The following descriptions indicate how range conditions work for multiple-part indexes in greater detail. * For `HASH' indexes, each interval containing identical values can be used. This means that the interval can be produced only for conditions in the following form: KEY_PART1 CMP CONST1 AND KEY_PART2 CMP CONST2 AND ... AND KEY_PARTN CMP CONSTN; Here, CONST1, CONST2, ... are constants, CMP is one of the `=', `<=>', or `IS NULL' comparison operators, and the conditions cover all index parts. (That is, there are N conditions, one for each part of an N-part index.) For example, the following is a range condition for a three-part `HASH' index: KEY_PART1 = 1 AND KEY_PART2 IS NULL AND KEY_PART3 = 'foo' For the definition of what is considered to be a constant, see *Note range-access-single-part::. * For a `BTREE' index, an interval might be usable for conditions combined with `AND', where each condition compares a key part with a constant value using `=', `<=>', `IS NULL', `>', `<', `>=', `<=', `!=', `<>', `BETWEEN', or `LIKE 'PATTERN'' (where `'PATTERN'' does not start with a wildcard). An interval can be used as long as it is possible to determine a single key tuple containing all rows that match the condition (or two intervals if `<>' or `!=' is used). The optimizer attempts to use additional key parts to determine the interval as long as the comparison operator is `=', `<=>', or `IS NULL'. If the operator is `>', `<', `>=', `<=', `!=', `<>', `BETWEEN', or `LIKE', the optimizer uses it but considers no more key parts. For the following expression, the optimizer uses `=' from the first comparison. It also uses `>=' from the second comparison but considers no further key parts and does not use the third comparison for interval construction: KEY_PART1 = 'foo' AND KEY_PART2 >= 10 AND KEY_PART3 > 10 The single interval is: ('foo',10,-inf) < (KEY_PART1,KEY_PART2,KEY_PART3) < ('foo',+inf,+inf) It is possible that the created interval contains more rows than the initial condition. For example, the preceding interval includes the value `('foo', 11, 0)', which does not satisfy the original condition. * If conditions that cover sets of rows contained within intervals are combined with `OR', they form a condition that covers a set of rows contained within the union of their intervals. If the conditions are combined with `AND', they form a condition that covers a set of rows contained within the intersection of their intervals. For example, for this condition on a two-part index: (KEY_PART1 = 1 AND KEY_PART2 < 2) OR (KEY_PART1 > 5) The intervals are: (1,-inf) < (KEY_PART1,KEY_PART2) < (1,2) (5,-inf) < (KEY_PART1,KEY_PART2) In this example, the interval on the first line uses one key part for the left bound and two key parts for the right bound. The interval on the second line uses only one key part. The `key_len' column in the *Note `EXPLAIN': explain. output indicates the maximum length of the key prefix used. In some cases, `key_len' may indicate that a key part was used, but that might be not what you would expect. Suppose that KEY_PART1 and KEY_PART2 can be `NULL'. Then the `key_len' column displays two key part lengths for the following condition: KEY_PART1 >= 1 AND KEY_PART2 < 2 But, in fact, the condition is converted to this: KEY_PART1 >= 1 AND KEY_PART2 IS NOT NULL *Note range-access-single-part::, describes how optimizations are performed to combine or eliminate intervals for range conditions on a single-part index. Analogous steps are performed for range conditions on multiple-part indexes.  File: manual.info, Node: index-merge-optimization, Next: condition-pushdown-optimization, Prev: range-optimization, Up: select-optimization 8.3.1.6 Index Merge Optimization ................................ * Menu: * index-merge-intersection:: The Index Merge Intersection Access Algorithm * index-merge-union:: The Index Merge Union Access Algorithm * index-merge-sort-union:: The Index Merge Sort-Union Access Algorithm The _Index Merge_ method is used to retrieve rows with several `range' scans and to merge their results into one. The merge can produce unions, intersections, or unions-of-intersections of its underlying scans. This access method merges index scans from a single table; it does not merge scans across multiple tables. In *Note `EXPLAIN': explain. output, the Index Merge method appears as `index_merge' in the `type' column. In this case, the `key' column contains a list of indexes used, and `key_len' contains a list of the longest key parts for those indexes. Examples: SELECT * FROM TBL_NAME WHERE KEY1 = 10 OR KEY2 = 20; SELECT * FROM TBL_NAME WHERE (KEY1 = 10 OR KEY2 = 20) AND NON_KEY=30; SELECT * FROM t1, t2 WHERE (t1.KEY1 IN (1,2) OR t1.KEY2 LIKE 'VALUE%') AND t2.KEY1=t1.SOME_COL; SELECT * FROM t1, t2 WHERE t1.KEY1=1 AND (t2.KEY1=t1.SOME_COL OR t2.KEY2=t1.SOME_COL2); The Index Merge method has several access algorithms (seen in the `Extra' field of *Note `EXPLAIN': explain. output): * `Using intersect(...)' * `Using union(...)' * `Using sort_union(...)' The following sections describe these methods in greater detail. *Note*: The Index Merge optimization algorithm has the following known deficiencies: * If a range scan is possible on some key, the optimizer will not consider using Index Merge Union or Index Merge Sort-Union algorithms. For example, consider this query: SELECT * FROM t1 WHERE (goodkey1 < 10 OR goodkey2 < 20) AND badkey < 30; For this query, two plans are possible: * An Index Merge scan using the `(goodkey1 < 10 OR goodkey2 < 20)' condition. * A range scan using the `badkey < 30' condition. However, the optimizer considers only the second plan. * If your query has a complex `WHERE' clause with deep `AND'/`OR' nesting and MySQL doesn't choose the optimal plan, try distributing terms using the following identity laws: (X AND Y) OR Z = (X OR Z) AND (Y OR Z) (X OR Y) AND Z = (X AND Z) OR (Y AND Z) * Index Merge is not applicable to full-text indexes. We plan to extend it to cover these in a future MySQL release. The choice between different possible variants of the Index Merge access method and other access methods is based on cost estimates of various available options.  File: manual.info, Node: index-merge-intersection, Next: index-merge-union, Prev: index-merge-optimization, Up: index-merge-optimization 8.3.1.7 The Index Merge Intersection Access Algorithm ..................................................... This access algorithm can be employed when a `WHERE' clause was converted to several range conditions on different keys combined with `AND', and each condition is one of the following: * In this form, where the index has exactly N parts (that is, all index parts are covered): KEY_PART1=CONST1 AND KEY_PART2=CONST2 ... AND KEY_PARTN=CONSTN * Any range condition over a primary key of an `InnoDB' table. Examples: SELECT * FROM INNODB_TABLE WHERE PRIMARY_KEY < 10 AND KEY_COL1=20; SELECT * FROM TBL_NAME WHERE (KEY1_PART1=1 AND KEY1_PART2=2) AND KEY2=2; The Index Merge intersection algorithm performs simultaneous scans on all used indexes and produces the intersection of row sequences that it receives from the merged index scans. If all columns used in the query are covered by the used indexes, full table rows are not retrieved (*Note `EXPLAIN': explain. output contains `Using index' in `Extra' field in this case). Here is an example of such a query: SELECT COUNT(*) FROM t1 WHERE key1=1 AND key2=1; If the used indexes don't cover all columns used in the query, full rows are retrieved only when the range conditions for all used keys are satisfied. If one of the merged conditions is a condition over a primary key of an `InnoDB' table, it is not used for row retrieval, but is used to filter out rows retrieved using other conditions.  File: manual.info, Node: index-merge-union, Next: index-merge-sort-union, Prev: index-merge-intersection, Up: index-merge-optimization 8.3.1.8 The Index Merge Union Access Algorithm .............................................. The applicability criteria for this algorithm are similar to those for the Index Merge method intersection algorithm. The algorithm can be employed when the table's `WHERE' clause was converted to several range conditions on different keys combined with `OR', and each condition is one of the following: * In this form, where the index has exactly N parts (that is, all index parts are covered): KEY_PART1=CONST1 AND KEY_PART2=CONST2 ... AND KEY_PARTN=CONSTN * Any range condition over a primary key of an `InnoDB' table. * A condition for which the Index Merge method intersection algorithm is applicable. Examples: SELECT * FROM t1 WHERE KEY1=1 OR KEY2=2 OR KEY3=3; SELECT * FROM INNODB_TABLE WHERE (KEY1=1 AND KEY2=2) OR (KEY3='foo' AND KEY4='bar') AND KEY5=5;  File: manual.info, Node: index-merge-sort-union, Prev: index-merge-union, Up: index-merge-optimization 8.3.1.9 The Index Merge Sort-Union Access Algorithm ................................................... This access algorithm is employed when the `WHERE' clause was converted to several range conditions combined by `OR', but for which the Index Merge method union algorithm is not applicable. Examples: SELECT * FROM TBL_NAME WHERE KEY_COL1 < 10 OR KEY_COL2 < 20; SELECT * FROM TBL_NAME WHERE (KEY_COL1 > 10 OR KEY_COL2 = 20) AND NONKEY_COL=30; The difference between the sort-union algorithm and the union algorithm is that the sort-union algorithm must first fetch row IDs for all rows and sort them before returning any rows.  File: manual.info, Node: condition-pushdown-optimization, Next: is-null-optimization, Prev: index-merge-optimization, Up: select-optimization 8.3.1.10 Engine Condition Pushdown Optimization ............................................... This optimization improves the efficiency of direct comparisons between a nonindexed column and a constant. In such cases, the condition is `pushed down' to the storage engine for evaluation. This optimization can be used only by the *Note `NDBCLUSTER': mysql-cluster. storage engine. For MySQL Cluster, this optimization can eliminate the need to send nonmatching rows over the network between the cluster's data nodes and the MySQL Server that issued the query, and can speed up queries where it is used by a factor of 5 to 10 times over cases where condition pushdown could be but is not used. Suppose that a MySQL Cluster table is defined as follows: CREATE TABLE t1 ( a INT, b INT, KEY(a) ) ENGINE=NDBCLUSTER; Condition pushdown can be used with queries such as the one shown here, which includes a comparison between a nonindexed column and a constant: SELECT a, b FROM t1 WHERE b = 10; The use of condition pushdown can be seen in the output of *Note `EXPLAIN': explain.: mysql> EXPLAIN SELECT a,b FROM t1 WHERE b = 10\G *************************** 1. row *************************** id: 1 select_type: SIMPLE table: t1 type: ALL possible_keys: NULL key: NULL key_len: NULL ref: NULL rows: 10 Extra: Using where with pushed condition However, condition pushdown _cannot_ be used with either of these two queries: SELECT a,b FROM t1 WHERE a = 10; SELECT a,b FROM t1 WHERE b + 1 = 10; Condition pushdown is not applicable to the first query because an index exists on column `a'. (An index access method would be more efficient and so would be chosen in preference to condition pushdown.) Condition pushdown cannot be employed for the second query because the comparison involving the nonindexed column `b' is indirect. (However, condition pushdown could be applied if you were to reduce `b + 1 = 10' to `b = 9' in the `WHERE' clause.) Condition pushdown may also be employed when an indexed column is compared with a constant using a `>' or `<' operator: mysql> EXPLAIN SELECT a, b FROM t1 WHERE a < 2\G *************************** 1. row *************************** id: 1 select_type: SIMPLE table: t1 type: range possible_keys: a key: a key_len: 5 ref: NULL rows: 2 Extra: Using where with pushed condition Other supported comparisons for condition pushdown include the following: * `COLUMN [NOT] LIKE PATTERN' PATTERN must be a string literal containing the pattern to be matched; for syntax, see *Note string-comparison-functions::. * `COLUMN IS [NOT] NULL' * `COLUMN IN (VALUE_LIST)' Each item in the VALUE_LIST must be a constant, literal value. * `COLUMN BETWEEN CONSTANT1 AND CONSTANT2' CONSTANT1 and CONSTANT2 must each be a constant, literal value. In all of the cases in the preceding list, it is possible for the condition to be converted into the form of one or more direct comparisons between a column and a constant. Engine condition pushdown is enabled by default. To disable it at server startup, set the `engine_condition_pushdown' system variable. For example, in a `my.cnf' file, use these lines: [mysqld] engine_condition_pushdown=0 At runtime, disable condition pushdown with either of the following statements: SET engine_condition_pushdown=OFF; SET engine_condition_pushdown=0; Limitations Engine condition pushdown is subject to the following limitations: * Condition pushdown is supported only by the *Note `NDBCLUSTER': mysql-cluster. storage engine. * Columns may be compared with constants only; however, this includes expressions which evaluate to constant values. * Columns used in comparisons cannot be of any of the *Note `BLOB': blob. or *Note `TEXT': blob. types. * A string value to be compared with a column must use the same collation as the column. * Joins are not directly supported; conditions involving multiple tables are pushed separately where possible. Use *Note `EXPLAIN EXTENDED': explain. to determine which conditions are actually pushed down.  File: manual.info, Node: is-null-optimization, Next: left-join-optimization, Prev: condition-pushdown-optimization, Up: select-optimization 8.3.1.11 `IS NULL' Optimization ............................... MySQL can perform the same optimization on COL_NAME `IS NULL' that it can use for COL_NAME `=' CONSTANT_VALUE. For example, MySQL can use indexes and ranges to search for `NULL' with `IS NULL'. Examples: SELECT * FROM TBL_NAME WHERE KEY_COL IS NULL; SELECT * FROM TBL_NAME WHERE KEY_COL <=> NULL; SELECT * FROM TBL_NAME WHERE KEY_COL=CONST1 OR KEY_COL=CONST2 OR KEY_COL IS NULL; If a `WHERE' clause includes a COL_NAME `IS NULL' condition for a column that is declared as `NOT NULL', that expression is optimized away. This optimization does not occur in cases when the column might produce `NULL' anyway; for example, if it comes from a table on the right side of a `LEFT JOIN'. MySQL can also optimize the combination `COL_NAME = EXPR OR COL_NAME IS NULL', a form that is common in resolved subqueries. *Note `EXPLAIN': explain. shows `ref_or_null' when this optimization is used. This optimization can handle one `IS NULL' for any key part. Some examples of queries that are optimized, assuming that there is an index on columns `a' and `b' of table `t2': SELECT * FROM t1 WHERE t1.a=EXPR OR t1.a IS NULL; SELECT * FROM t1, t2 WHERE t1.a=t2.a OR t2.a IS NULL; SELECT * FROM t1, t2 WHERE (t1.a=t2.a OR t2.a IS NULL) AND t2.b=t1.b; SELECT * FROM t1, t2 WHERE t1.a=t2.a AND (t2.b=t1.b OR t2.b IS NULL); SELECT * FROM t1, t2 WHERE (t1.a=t2.a AND t2.a IS NULL AND ...) OR (t1.a=t2.a AND t2.a IS NULL AND ...); `ref_or_null' works by first doing a read on the reference key, and then a separate search for rows with a `NULL' key value. Note that the optimization can handle only one `IS NULL' level. In the following query, MySQL uses key lookups only on the expression `(t1.a=t2.a AND t2.a IS NULL)' and is not able to use the key part on `b': SELECT * FROM t1, t2 WHERE (t1.a=t2.a AND t2.a IS NULL) OR (t1.b=t2.b AND t2.b IS NULL);  File: manual.info, Node: left-join-optimization, Next: nested-loop-joins, Prev: is-null-optimization, Up: select-optimization 8.3.1.12 `LEFT JOIN' and `RIGHT JOIN' Optimization .................................................. MySQL implements an `A LEFT JOIN B join_condition' as follows: * Table B is set to depend on table A and all tables on which A depends. * Table A is set to depend on all tables (except B) that are used in the `LEFT JOIN' condition. * The `LEFT JOIN' condition is used to decide how to retrieve rows from table B. (In other words, any condition in the `WHERE' clause is not used.) * All standard join optimizations are performed, with the exception that a table is always read after all tables on which it depends. If there is a circular dependence, MySQL issues an error. * All standard `WHERE' optimizations are performed. * If there is a row in A that matches the `WHERE' clause, but there is no row in B that matches the `ON' condition, an extra B row is generated with all columns set to `NULL'. * If you use `LEFT JOIN' to find rows that do not exist in some table and you have the following test: `COL_NAME IS NULL' in the `WHERE' part, where COL_NAME is a column that is declared as `NOT NULL', MySQL stops searching for more rows (for a particular key combination) after it has found one row that matches the `LEFT JOIN' condition. The implementation of `RIGHT JOIN' is analogous to that of `LEFT JOIN' with the roles of the tables reversed. The join optimizer calculates the order in which tables should be joined. The table read order forced by `LEFT JOIN' or `STRAIGHT_JOIN' helps the join optimizer do its work much more quickly, because there are fewer table permutations to check. Note that this means that if you do a query of the following type, MySQL does a full scan on `b' because the `LEFT JOIN' forces it to be read before `d': SELECT * FROM a JOIN b LEFT JOIN c ON (c.key=a.key) LEFT JOIN d ON (d.key=a.key) WHERE b.key=d.key; The fix in this case is reverse the order in which `a' and `b' are listed in the `FROM' clause: SELECT * FROM b JOIN a LEFT JOIN c ON (c.key=a.key) LEFT JOIN d ON (d.key=a.key) WHERE b.key=d.key; For a `LEFT JOIN', if the `WHERE' condition is always false for the generated `NULL' row, the `LEFT JOIN' is changed to a normal join. For example, the `WHERE' clause would be false in the following query if `t2.column1' were `NULL': SELECT * FROM t1 LEFT JOIN t2 ON (column1) WHERE t2.column2=5; Therefore, it is safe to convert the query to a normal join: SELECT * FROM t1, t2 WHERE t2.column2=5 AND t1.column1=t2.column1; This can be made faster because MySQL can use table `t2' before table `t1' if doing so would result in a better query plan. To provide a hint about the table join order, use `STRAIGHT_JOIN'. (See *Note select::.)  File: manual.info, Node: nested-loop-joins, Next: nested-join-optimization, Prev: left-join-optimization, Up: select-optimization 8.3.1.13 Nested-Loop Join Algorithms .................................... MySQL executes joins between tables using a nested-loop algorithm or variations on it. *Nested-Loop Join Algorithm* A simple nested-loop join (NLJ) algorithm reads rows from the first table in a loop one at a time, passing each row to a nested loop that processes the next table in the join. This process is repeated as many times as there remain tables to be joined. Assume that a join between three tables `t1', `t2', and `t3' is to be executed using the following join types: Table Join Type t1 range t2 ref t3 ALL If a simple NLJ algorithm is used, the join is processed like this: for each row in t1 matching range { for each row in t2 matching reference key { for each row in t3 { if row satisfies join conditions, send to client } } } Because the NLJ algorithm passes rows one at a time from outer loops to inner loops, it typically reads tables processed in the inner loops many times. *Block Nested-Loop Join Algorithm* A Block Nested-Loop (BNL) Join algorithm uses buffering of rows read in outer loops to reduce the number of times that tables in inner loops must be read. For example, if 10 rows are read into a buffer and the buffer is passed to the next inner loop, each row read in the inner loop can be compared against all 10 rows in the buffer. The reduces the number of times the inner table must be read by an order of magnitude. MySQL uses join buffering under these conditions: * The `join_buffer_size' system variable determines the size of each join buffer. * Join buffering can be used when the join is of type `ALL' or `index' (in other words, when no possible keys can be used, and a full scan is done, of either the data or index rows, respectively), or `range'. * One buffer is allocated for each join that can be buffered, so a given query might be processed using multiple join buffers. * A join buffer is never allocated for the first nonconst table, even if it would be of type `ALL' or `index'. * A join buffer is allocated prior to executing the join and freed after the query is done. * Only columns of interest to the join are stored in the join buffer, not whole rows. For the example join described previously for the NLJ algorithm (without buffering), the join is done as follow using join buffering: for each row in t1 matching range { for each row in t2 matching reference key { store used columns from t1, t2 in join buffer if buffer is full { for each row in t3 { for each t1, t2 combination in join buffer { if row satisfies join conditions, send to client } } empty buffer } } } if buffer is not empty { for each row in t3 { for each t1, t2 combination in join buffer { if row satisfies join conditions, send to client } } } If S is the size of each stored `t1', `t2' combination is the join buffer and C is the number of combinations in the buffer, the number of times table `t3' is scanned is: (S * C)/join_buffer_size + 1 The number of `t3' scans decreases as the value of `join_buffer_size' increases, up to the point when `join_buffer_size' is large enough to hold all previous row combinations. At that point, there is no speed to be gained by making it larger.  File: manual.info, Node: nested-join-optimization, Next: outer-join-simplification, Prev: nested-loop-joins, Up: select-optimization 8.3.1.14 Nested Join Optimization ................................. The syntax for expressing joins permits nested joins. The following discussion refers to the join syntax described in *Note join::. The syntax of TABLE_FACTOR is extended in comparison with the SQL Standard. The latter accepts only TABLE_REFERENCE, not a list of them inside a pair of parentheses. This is a conservative extension if we consider each comma in a list of TABLE_REFERENCE items as equivalent to an inner join. For example: SELECT * FROM t1 LEFT JOIN (t2, t3, t4) ON (t2.a=t1.a AND t3.b=t1.b AND t4.c=t1.c) is equivalent to: SELECT * FROM t1 LEFT JOIN (t2 CROSS JOIN t3 CROSS JOIN t4) ON (t2.a=t1.a AND t3.b=t1.b AND t4.c=t1.c) In MySQL, `CROSS JOIN' is a syntactic equivalent to `INNER JOIN' (they can replace each other). In standard SQL, they are not equivalent. `INNER JOIN' is used with an `ON' clause; `CROSS JOIN' is used otherwise. In general, parentheses can be ignored in join expressions containing only inner join operations. After removing parentheses and grouping operations to the left, the join expression: t1 LEFT JOIN (t2 LEFT JOIN t3 ON t2.b=t3.b OR t2.b IS NULL) ON t1.a=t2.a transforms into the expression: (t1 LEFT JOIN t2 ON t1.a=t2.a) LEFT JOIN t3 ON t2.b=t3.b OR t2.b IS NULL Yet, the two expressions are not equivalent. To see this, suppose that the tables `t1', `t2', and `t3' have the following state: * Table `t1' contains rows `(1)', `(2)' * Table `t2' contains row `(1,101)' * Table `t3' contains row `(101)' In this case, the first expression returns a result set including the rows `(1,1,101,101)', `(2,NULL,NULL,NULL)', whereas the second expression returns the rows `(1,1,101,101)', `(2,NULL,NULL,101)': mysql> SELECT * -> FROM t1 -> LEFT JOIN -> (t2 LEFT JOIN t3 ON t2.b=t3.b OR t2.b IS NULL) -> ON t1.a=t2.a; +------+------+------+------+ | a | a | b | b | +------+------+------+------+ | 1 | 1 | 101 | 101 | | 2 | NULL | NULL | NULL | +------+------+------+------+ mysql> SELECT * -> FROM (t1 LEFT JOIN t2 ON t1.a=t2.a) -> LEFT JOIN t3 -> ON t2.b=t3.b OR t2.b IS NULL; +------+------+------+------+ | a | a | b | b | +------+------+------+------+ | 1 | 1 | 101 | 101 | | 2 | NULL | NULL | 101 | +------+------+------+------+ In the following example, an outer join operation is used together with an inner join operation: t1 LEFT JOIN (t2, t3) ON t1.a=t2.a That expression cannot be transformed into the following expression: t1 LEFT JOIN t2 ON t1.a=t2.a, t3. For the given table states, the two expressions return different sets of rows: mysql> SELECT * -> FROM t1 LEFT JOIN (t2, t3) ON t1.a=t2.a; +------+------+------+------+ | a | a | b | b | +------+------+------+------+ | 1 | 1 | 101 | 101 | | 2 | NULL | NULL | NULL | +------+------+------+------+ mysql> SELECT * -> FROM t1 LEFT JOIN t2 ON t1.a=t2.a, t3; +------+------+------+------+ | a | a | b | b | +------+------+------+------+ | 1 | 1 | 101 | 101 | | 2 | NULL | NULL | 101 | +------+------+------+------+ Therefore, if we omit parentheses in a join expression with outer join operators, we might change the result set for the original expression. More exactly, we cannot ignore parentheses in the right operand of the left outer join operation and in the left operand of a right join operation. In other words, we cannot ignore parentheses for the inner table expressions of outer join operations. Parentheses for the other operand (operand for the outer table) can be ignored. The following expression: (t1,t2) LEFT JOIN t3 ON P(t2.b,t3.b) is equivalent to this expression: t1, t2 LEFT JOIN t3 ON P(t2.b,t3.b) for any tables `t1,t2,t3' and any condition `P' over attributes `t2.b' and `t3.b'. Whenever the order of execution of the join operations in a join expression (JOIN_TABLE) is not from left to right, we talk about nested joins. Consider the following queries: SELECT * FROM t1 LEFT JOIN (t2 LEFT JOIN t3 ON t2.b=t3.b) ON t1.a=t2.a WHERE t1.a > 1 SELECT * FROM t1 LEFT JOIN (t2, t3) ON t1.a=t2.a WHERE (t2.b=t3.b OR t2.b IS NULL) AND t1.a > 1 Those queries are considered to contain these nested joins: t2 LEFT JOIN t3 ON t2.b=t3.b t2, t3 The nested join is formed in the first query with a left join operation, whereas in the second query it is formed with an inner join operation. In the first query, the parentheses can be omitted: The grammatical structure of the join expression will dictate the same order of execution for join operations. For the second query, the parentheses cannot be omitted, although the join expression here can be interpreted unambiguously without them. (In our extended syntax the parentheses in `(t2, t3)' of the second query are required, although theoretically the query could be parsed without them: We still would have unambiguous syntactical structure for the query because `LEFT JOIN' and `ON' would play the role of the left and right delimiters for the expression `(t2,t3)'.) The preceding examples demonstrate these points: * For join expressions involving only inner joins (and not outer joins), parentheses can be removed. You can remove parentheses and evaluate left to right (or, in fact, you can evaluate the tables in any order). * The same is not true, in general, for outer joins or for outer joins mixed with inner joins. Removal of parentheses may change the result. Queries with nested outer joins are executed in the same pipeline manner as queries with inner joins. More exactly, a variation of the nested-loop join algorithm is exploited. Recall by what algorithmic schema the nested-loop join executes a query. Suppose that we have a join query over 3 tables `T1,T2,T3' of the form: SELECT * FROM T1 INNER JOIN T2 ON P1(T1,T2) INNER JOIN T3 ON P2(T2,T3) WHERE P(T1,T2,T3). Here, `P1(T1,T2)' and `P2(T3,T3)' are some join conditions (on expressions), whereas `P(t1,t2,t3)' is a condition over columns of tables `T1,T2,T3'. The nested-loop join algorithm would execute this query in the following manner: FOR each row t1 in T1 { FOR each row t2 in T2 such that P1(t1,t2) { FOR each row t3 in T3 such that P2(t2,t3) { IF P(t1,t2,t3) { t:=t1||t2||t3; OUTPUT t; } } } } The notation `t1||t2||t3' means `a row constructed by concatenating the columns of rows `t1', `t2', and `t3'.' In some of the following examples, `NULL' where a row name appears means that `NULL' is used for each column of that row. For example, `t1||t2||NULL' means `a row constructed by concatenating the columns of rows `t1' and `t2', and `NULL' for each column of `t3'.' Now let's consider a query with nested outer joins: SELECT * FROM T1 LEFT JOIN (T2 LEFT JOIN T3 ON P2(T2,T3)) ON P1(T1,T2) WHERE P(T1,T2,T3). For this query, we modify the nested-loop pattern to get: FOR each row t1 in T1 { BOOL f1:=FALSE; FOR each row t2 in T2 such that P1(t1,t2) { BOOL f2:=FALSE; FOR each row t3 in T3 such that P2(t2,t3) { IF P(t1,t2,t3) { t:=t1||t2||t3; OUTPUT t; } f2=TRUE; f1=TRUE; } IF (!f2) { IF P(t1,t2,NULL) { t:=t1||t2||NULL; OUTPUT t; } f1=TRUE; } } IF (!f1) { IF P(t1,NULL,NULL) { t:=t1||NULL||NULL; OUTPUT t; } } } In general, for any nested loop for the first inner table in an outer join operation, a flag is introduced that is turned off before the loop and is checked after the loop. The flag is turned on when for the current row from the outer table a match from the table representing the inner operand is found. If at the end of the loop cycle the flag is still off, no match has been found for the current row of the outer table. In this case, the row is complemented by `NULL' values for the columns of the inner tables. The result row is passed to the final check for the output or into the next nested loop, but only if the row satisfies the join condition of all embedded outer joins. In our example, the outer join table expressed by the following expression is embedded: (T2 LEFT JOIN T3 ON P2(T2,T3)) Note that for the query with inner joins, the optimizer could choose a different order of nested loops, such as this one: FOR each row t3 in T3 { FOR each row t2 in T2 such that P2(t2,t3) { FOR each row t1 in T1 such that P1(t1,t2) { IF P(t1,t2,t3) { t:=t1||t2||t3; OUTPUT t; } } } } For the queries with outer joins, the optimizer can choose only such an order where loops for outer tables precede loops for inner tables. Thus, for our query with outer joins, only one nesting order is possible. For the following query, the optimizer will evaluate two different nestings: SELECT * T1 LEFT JOIN (T2,T3) ON P1(T1,T2) AND P2(T1,T3) WHERE P(T1,T2,T3) The nestings are these: FOR each row t1 in T1 { BOOL f1:=FALSE; FOR each row t2 in T2 such that P1(t1,t2) { FOR each row t3 in T3 such that P2(t1,t3) { IF P(t1,t2,t3) { t:=t1||t2||t3; OUTPUT t; } f1:=TRUE } } IF (!f1) { IF P(t1,NULL,NULL) { t:=t1||NULL||NULL; OUTPUT t; } } } and: FOR each row t1 in T1 { BOOL f1:=FALSE; FOR each row t3 in T3 such that P2(t1,t3) { FOR each row t2 in T2 such that P1(t1,t2) { IF P(t1,t2,t3) { t:=t1||t2||t3; OUTPUT t; } f1:=TRUE } } IF (!f1) { IF P(t1,NULL,NULL) { t:=t1||NULL||NULL; OUTPUT t; } } } In both nestings, `T1' must be processed in the outer loop because it is used in an outer join. `T2' and `T3' are used in an inner join, so that join must be processed in the inner loop. However, because the join is an inner join, `T2' and `T3' can be processed in either order. When discussing the nested-loop algorithm for inner joins, we omitted some details whose impact on the performance of query execution may be huge. We did not mention so-called `pushed-down' conditions. Suppose that our `WHERE' condition `P(T1,T2,T3)' can be represented by a conjunctive formula: P(T1,T2,T2) = C1(T1) AND C2(T2) AND C3(T3). In this case, MySQL actually uses the following nested-loop schema for the execution of the query with inner joins: FOR each row t1 in T1 such that C1(t1) { FOR each row t2 in T2 such that P1(t1,t2) AND C2(t2) { FOR each row t3 in T3 such that P2(t2,t3) AND C3(t3) { IF P(t1,t2,t3) { t:=t1||t2||t3; OUTPUT t; } } } } You see that each of the conjuncts `C1(T1)', `C2(T2)', `C3(T3)' are pushed out of the most inner loop to the most outer loop where it can be evaluated. If `C1(T1)' is a very restrictive condition, this condition pushdown may greatly reduce the number of rows from table `T1' passed to the inner loops. As a result, the execution time for the query may improve immensely. For a query with outer joins, the `WHERE' condition is to be checked only after it has been found that the current row from the outer table has a match in the inner tables. Thus, the optimization of pushing conditions out of the inner nested loops cannot be applied directly to queries with outer joins. Here we have to introduce conditional pushed-down predicates guarded by the flags that are turned on when a match has been encountered. For our example with outer joins with: P(T1,T2,T3)=C1(T1) AND C(T2) AND C3(T3) the nested-loop schema using guarded pushed-down conditions looks like this: FOR each row t1 in T1 such that C1(t1) { BOOL f1:=FALSE; FOR each row t2 in T2 such that P1(t1,t2) AND (f1?C2(t2):TRUE) { BOOL f2:=FALSE; FOR each row t3 in T3 such that P2(t2,t3) AND (f1&&f2?C3(t3):TRUE) { IF (f1&&f2?TRUE:(C2(t2) AND C3(t3))) { t:=t1||t2||t3; OUTPUT t; } f2=TRUE; f1=TRUE; } IF (!f2) { IF (f1?TRUE:C2(t2) && P(t1,t2,NULL)) { t:=t1||t2||NULL; OUTPUT t; } f1=TRUE; } } IF (!f1 && P(t1,NULL,NULL)) { t:=t1||NULL||NULL; OUTPUT t; } } In general, pushed-down predicates can be extracted from join conditions such as `P1(T1,T2)' and `P(T2,T3)'. In this case, a pushed-down predicate is guarded also by a flag that prevents checking the predicate for the `NULL'-complemented row generated by the corresponding outer join operation. Note that access by key from one inner table to another in the same nested join is prohibited if it is induced by a predicate from the `WHERE' condition. (We could use conditional key access in this case, but this technique is not employed yet in MySQL 5.1.)  File: manual.info, Node: outer-join-simplification, Next: order-by-optimization, Prev: nested-join-optimization, Up: select-optimization 8.3.1.15 Outer Join Simplification .................................. Table expressions in the `FROM' clause of a query are simplified in many cases. At the parser stage, queries with right outer joins operations are converted to equivalent queries containing only left join operations. In the general case, the conversion is performed according to the following rule: (T1, ...) RIGHT JOIN (T2,...) ON P(T1,...,T2,...) = (T2, ...) LEFT JOIN (T1,...) ON P(T1,...,T2,...) All inner join expressions of the form `T1 INNER JOIN T2 ON P(T1,T2)' are replaced by the list `T1,T2', `P(T1,T2)' being joined as a conjunct to the `WHERE' condition (or to the join condition of the embedding join, if there is any). When the optimizer evaluates plans for join queries with outer join operation, it takes into consideration only the plans where, for each such operation, the outer tables are accessed before the inner tables. The optimizer options are limited because only such plans enables us to execute queries with outer joins operations by the nested loop schema. Suppose that we have a query of the form: SELECT * T1 LEFT JOIN T2 ON P1(T1,T2) WHERE P(T1,T2) AND R(T2) with `R(T2)' narrowing greatly the number of matching rows from table `T2'. If we executed the query as it is, the optimizer would have no other choice besides to access table `T1' before table `T2' that may lead to a very inefficient execution plan. Fortunately, MySQL converts such a query into a query without an outer join operation if the `WHERE' condition is null-rejected. A condition is called null-rejected for an outer join operation if it evaluates to `FALSE' or to `UNKNOWN' for any `NULL'-complemented row built for the operation. Thus, for this outer join: T1 LEFT JOIN T2 ON T1.A=T2.A Conditions such as these are null-rejected: T2.B IS NOT NULL, T2.B > 3, T2.C <= T1.C, T2.B < 2 OR T2.C > 1 Conditions such as these are not null-rejected: T2.B IS NULL, T1.B < 3 OR T2.B IS NOT NULL, T1.B < 3 OR T2.B > 3 The general rules for checking whether a condition is null-rejected for an outer join operation are simple. A condition is null-rejected in the following cases: * If it is of the form `A IS NOT NULL', where `A' is an attribute of any of the inner tables * If it is a predicate containing a reference to an inner table that evaluates to `UNKNOWN' when one of its arguments is `NULL' * If it is a conjunction containing a null-rejected condition as a conjunct * If it is a disjunction of null-rejected conditions A condition can be null-rejected for one outer join operation in a query and not null-rejected for another. In the query: SELECT * FROM T1 LEFT JOIN T2 ON T2.A=T1.A LEFT JOIN T3 ON T3.B=T1.B WHERE T3.C > 0 the `WHERE' condition is null-rejected for the second outer join operation but is not null-rejected for the first one. If the `WHERE' condition is null-rejected for an outer join operation in a query, the outer join operation is replaced by an inner join operation. For example, the preceding query is replaced with the query: SELECT * FROM T1 LEFT JOIN T2 ON T2.A=T1.A INNER JOIN T3 ON T3.B=T1.B WHERE T3.C > 0 For the original query, the optimizer would evaluate plans compatible with only one access order `T1,T2,T3'. For the replacing query, it additionally considers the access sequence `T3,T1,T2'. A conversion of one outer join operation may trigger a conversion of another. Thus, the query: SELECT * FROM T1 LEFT JOIN T2 ON T2.A=T1.A LEFT JOIN T3 ON T3.B=T2.B WHERE T3.C > 0 will be first converted to the query: SELECT * FROM T1 LEFT JOIN T2 ON T2.A=T1.A INNER JOIN T3 ON T3.B=T2.B WHERE T3.C > 0 which is equivalent to the query: SELECT * FROM (T1 LEFT JOIN T2 ON T2.A=T1.A), T3 WHERE T3.C > 0 AND T3.B=T2.B Now the remaining outer join operation can be replaced by an inner join, too, because the condition `T3.B=T2.B' is null-rejected and we get a query without outer joins at all: SELECT * FROM (T1 INNER JOIN T2 ON T2.A=T1.A), T3 WHERE T3.C > 0 AND T3.B=T2.B Sometimes we succeed in replacing an embedded outer join operation, but cannot convert the embedding outer join. The following query: SELECT * FROM T1 LEFT JOIN (T2 LEFT JOIN T3 ON T3.B=T2.B) ON T2.A=T1.A WHERE T3.C > 0 is converted to: SELECT * FROM T1 LEFT JOIN (T2 INNER JOIN T3 ON T3.B=T2.B) ON T2.A=T1.A WHERE T3.C > 0, That can be rewritten only to the form still containing the embedding outer join operation: SELECT * FROM T1 LEFT JOIN (T2,T3) ON (T2.A=T1.A AND T3.B=T2.B) WHERE T3.C > 0. When trying to convert an embedded outer join operation in a query, we must take into account the join condition for the embedding outer join together with the `WHERE' condition. In the query: SELECT * FROM T1 LEFT JOIN (T2 LEFT JOIN T3 ON T3.B=T2.B) ON T2.A=T1.A AND T3.C=T1.C WHERE T3.D > 0 OR T1.D > 0 the `WHERE' condition is not null-rejected for the embedded outer join, but the join condition of the embedding outer join `T2.A=T1.A AND T3.C=T1.C' is null-rejected. So the query can be converted to: SELECT * FROM T1 LEFT JOIN (T2, T3) ON T2.A=T1.A AND T3.C=T1.C AND T3.B=T2.B WHERE T3.D > 0 OR T1.D > 0  File: manual.info, Node: order-by-optimization, Next: group-by-optimization, Prev: outer-join-simplification, Up: select-optimization 8.3.1.16 `ORDER BY' Optimization ................................ In some cases, MySQL can use an index to satisfy an `ORDER BY' clause without doing any extra sorting. The index can also be used even if the `ORDER BY' does not match the index exactly, as long as all of the unused portions of the index and all the extra `ORDER BY' columns are constants in the `WHERE' clause. The following queries use the index to resolve the `ORDER BY' part: SELECT * FROM t1 ORDER BY KEY_PART1,KEY_PART2,... ; SELECT * FROM t1 WHERE KEY_PART1=CONSTANT ORDER BY KEY_PART2; SELECT * FROM t1 ORDER BY KEY_PART1 DESC, KEY_PART2 DESC; SELECT * FROM t1 WHERE KEY_PART1=1 ORDER BY KEY_PART1 DESC, KEY_PART2 DESC; In some cases, MySQL _cannot_ use indexes to resolve the `ORDER BY', although it still uses indexes to find the rows that match the `WHERE' clause. These cases include the following: * You use `ORDER BY' on different keys: SELECT * FROM t1 ORDER BY KEY1, KEY2; * You use `ORDER BY' on nonconsecutive parts of a key: SELECT * FROM t1 WHERE KEY2=CONSTANT ORDER BY KEY_PART2; * You mix `ASC' and `DESC': SELECT * FROM t1 ORDER BY KEY_PART1 DESC, KEY_PART2 ASC; * The key used to fetch the rows is not the same as the one used in the `ORDER BY': SELECT * FROM t1 WHERE KEY2=CONSTANT ORDER BY KEY1; * You use `ORDER BY' with an expression that includes terms other than the key column name: SELECT * FROM t1 ORDER BY ABS(KEY); SELECT * FROM t1 ORDER BY -KEY; * You are joining many tables, and the columns in the `ORDER BY' are not all from the first nonconstant table that is used to retrieve rows. (This is the first table in the *Note `EXPLAIN': explain. output that does not have a `const' join type.) * You have different `ORDER BY' and `GROUP BY' expressions. * You index only a prefix of a column named in the `ORDER BY' clause. In this case, the index cannot be used to fully resolve the sort order. For example, if you have a *Note `CHAR(20)': char. column, but index only the first 10 bytes, the index cannot distinguish values past the 10th byte and a `filesort' will be needed. * The type of table index used does not store rows in order. For example, this is true for a `HASH' index in a `MEMORY' table. Availability of an index for sorting may be affected by the use of column aliases. Suppose that the column `t1.a' is indexed. In this statement, the name of the column in the select list is `a'. It refers to `t1.a', so for the reference to `a' in the `ORDER BY', the index can be used: SELECT a FROM t1 ORDER BY a; In this statement, the name of the column in the select list is also `a', but it is the alias name. It refers to `ABS(a)', so for the reference to `a' in the `ORDER BY', the index cannot be used: SELECT ABS(a) AS a FROM t1 ORDER BY a; In the following statement, the `ORDER BY' refers to a name that is not the name of a column in the select list. But there is a column in `t1' named `a', so the `ORDER BY' uses that, and the index can be used. (The resulting sort order may be completely different from the order for `ABS(a)', of course.) SELECT ABS(a) AS b FROM t1 ORDER BY a; By default, MySQL sorts all `GROUP BY COL1, COL2, ...' queries as if you specified `ORDER BY COL1, COL2, ...' in the query as well. If you include an `ORDER BY' clause explicitly that contains the same column list, MySQL optimizes it away without any speed penalty, although the sorting still occurs. If a query includes `GROUP BY' but you want to avoid the overhead of sorting the result, you can suppress sorting by specifying `ORDER BY NULL'. For example: INSERT INTO foo SELECT a, COUNT(*) FROM bar GROUP BY a ORDER BY NULL; With *Note `EXPLAIN SELECT ... ORDER BY': explain, you can check whether MySQL can use indexes to resolve the query. It cannot if you see `Using filesort' in the `Extra' column. See *Note using-explain::. Filesort uses a fixed-length row-storage format similar to that used by the *Note `MEMORY': memory-storage-engine. storage engine. Variable-length types such as *Note `VARCHAR': char. are stored using a fixed length. MySQL has two `filesort' algorithms for sorting and retrieving results. The original method uses only the `ORDER BY' columns. The modified method uses not just the `ORDER BY' columns, but all the columns used in the query. The optimizer selects which `filesort' algorithm to use. It normally uses the modified algorithm except when *Note `BLOB': blob. or *Note `TEXT': blob. columns are involved, in which case it uses the original algorithm. The original `filesort' algorithm works as follows: 1. Read all rows according to key or by table scanning. Rows that do not match the `WHERE' clause are skipped. 2. For each row, store a pair of values in a buffer (the sort key and the row pointer). The size of the buffer is the value of the `sort_buffer_size' system variable. 3. When the buffer gets full, run a qsort (quicksort) on it and store the result in a temporary file. Save a pointer to the sorted block. (If all pairs fit into the sort buffer, no temporary file is created.) 4. Repeat the preceding steps until all rows have been read. 5. Do a multi-merge of up to `MERGEBUFF' (7) regions to one block in another temporary file. Repeat until all blocks from the first file are in the second file. 6. Repeat the following until there are fewer than `MERGEBUFF2' (15) blocks left. 7. On the last multi-merge, only the pointer to the row (the last part of the sort key) is written to a result file. 8. Read the rows in sorted order by using the row pointers in the result file. To optimize this, we read in a big block of row pointers, sort them, and use them to read the rows in sorted order into a row buffer. The size of the buffer is the value of the `read_rnd_buffer_size' system variable. The code for this step is in the `sql/records.cc' source file. One problem with this approach is that it reads rows twice: One time when evaluating the `WHERE' clause, and again after sorting the pair values. And even if the rows were accessed successively the first time (for example, if a table scan is done), the second time they are accessed randomly. (The sort keys are ordered, but the row positions are not.) The modified `filesort' algorithm incorporates an optimization such that it records not only the sort key value and row position, but also the columns required for the query. This avoids reading the rows twice. The modified `filesort' algorithm works like this: 1. Read the rows that match the `WHERE' clause. 2. For each row, record a tuple of values consisting of the sort key value and row position, and also the columns required for the query. 3. Sort the tuples by sort key value 4. Retrieve the rows in sorted order, but read the required columns directly from the sorted tuples rather than by accessing the table a second time. Using the modified `filesort' algorithm, the tuples are longer than the pairs used in the original method, and fewer of them fit in the sort buffer (the size of which is given by `sort_buffer_size'). As a result, it is possible for the extra I/O to make the modified approach slower, not faster. To avoid a slowdown, the optimization is used only if the total size of the extra columns in the sort tuple does not exceed the value of the `max_length_for_sort_data' system variable. (A symptom of setting the value of this variable too high is that you should see high disk activity and low CPU activity.) For slow queries for which `filesort' is not used, you might try lowering `max_length_for_sort_data' to a value that is appropriate to trigger a `filesort'. If you want to increase `ORDER BY' speed, check whether you can get MySQL to use indexes rather than an extra sorting phase. If this is not possible, you can try the following strategies: * Increase the size of the `sort_buffer_size' variable. * Increase the size of the `read_rnd_buffer_size' variable. * Use less RAM per row by declaring columns only as large as they need to be to hold the values stored in them. For example, `CHAR(16)' is better than `CHAR(200)' if values never exceed 16 characters. * Change `tmpdir' to point to a dedicated file system with large amounts of free space. Also, this option accepts several paths that are used in round-robin fashion, so you can use this feature to spread the load across several directories. Paths should be separated by colon characters (``:'') on Unix and semicolon characters (``;'') on Windows, NetWare, and OS/2. The paths should be for directories in file systems that are located on different _physical_ disks, not different partitions on the same disk.  File: manual.info, Node: group-by-optimization, Next: distinct-optimization, Prev: order-by-optimization, Up: select-optimization 8.3.1.17 `GROUP BY' Optimization ................................ * Menu: * loose-index-scan:: Loose Index Scan * tight-index-scan:: Tight Index Scan The most general way to satisfy a `GROUP BY' clause is to scan the whole table and create a new temporary table where all rows from each group are consecutive, and then use this temporary table to discover groups and apply aggregate functions (if any). In some cases, MySQL is able to do much better than that and to avoid creation of temporary tables by using index access. The most important preconditions for using indexes for `GROUP BY' are that all `GROUP BY' columns reference attributes from the same index, and that the index stores its keys in order (for example, this is a `BTREE' index and not a `HASH' index). Whether use of temporary tables can be replaced by index access also depends on which parts of an index are used in a query, the conditions specified for these parts, and the selected aggregate functions. There are two ways to execute a `GROUP BY' query through index access, as detailed in the following sections. In the first method, the grouping operation is applied together with all range predicates (if any). The second method first performs a range scan, and then groups the resulting tuples. In MySQL, `GROUP BY' is used for sorting, so the server may also apply `ORDER BY' optimizations to grouping. See *Note order-by-optimization::.  File: manual.info, Node: loose-index-scan, Next: tight-index-scan, Prev: group-by-optimization, Up: group-by-optimization 8.3.1.18 Loose Index Scan ......................... The most efficient way to process `GROUP BY' is when an index is used to directly retrieve the grouping columns. With this access method, MySQL uses the property of some index types that the keys are ordered (for example, `BTREE'). This property enables use of lookup groups in an index without having to consider all keys in the index that satisfy all `WHERE' conditions. This access method considers only a fraction of the keys in an index, so it is called a _loose index scan_. When there is no `WHERE' clause, a loose index scan reads as many keys as the number of groups, which may be a much smaller number than that of all keys. If the `WHERE' clause contains range predicates (see the discussion of the `range' join type in *Note using-explain::), a loose index scan looks up the first key of each group that satisfies the range conditions, and again reads the least possible number of keys. This is possible under the following conditions: * The query is over a single table. * The `GROUP BY' names only columns that form a leftmost prefix of the index and no other columns. (If, instead of `GROUP BY', the query has a `DISTINCT' clause, all distinct attributes refer to columns that form a leftmost prefix of the index.) For example, if a table `t1' has an index on `(c1,c2,c3)', loose index scan is applicable if the query has `GROUP BY c1, c2,'. It is not applicable if the query has `GROUP BY c2, c3' (the columns are not a leftmost prefix) or `GROUP BY c1, c2, c4' (`c4' is not in the index). * The only aggregate functions used in the select list (if any) are `MIN()' and `MAX()', and all of them refer to the same column. The column must be in the index and must follow the columns in the `GROUP BY'. * Any other parts of the index than those from the `GROUP BY' referenced in the query must be constants (that is, they must be referenced in equalities with constants), except for the argument of `MIN()' or `MAX()' functions. * For columns in the index, full column values must be indexed, not just a prefix. For example, with `c1 VARCHAR(20), INDEX (c1(10))', the index cannot be used for loose index scan. If loose index scan is applicable to a query, the *Note `EXPLAIN': explain. output shows `Using index for group-by' in the `Extra' column. Assume that there is an index `idx(c1,c2,c3)' on table `t1(c1,c2,c3,c4)'. The loose index scan access method can be used for the following queries: SELECT c1, c2 FROM t1 GROUP BY c1, c2; SELECT DISTINCT c1, c2 FROM t1; SELECT c1, MIN(c2) FROM t1 GROUP BY c1; SELECT c1, c2 FROM t1 WHERE c1 < CONST GROUP BY c1, c2; SELECT MAX(c3), MIN(c3), c1, c2 FROM t1 WHERE c2 > CONST GROUP BY c1, c2; SELECT c2 FROM t1 WHERE c1 < CONST GROUP BY c1, c2; SELECT c1, c2 FROM t1 WHERE c3 = CONST GROUP BY c1, c2; The following queries cannot be executed with this quick select method, for the reasons given: * There are aggregate functions other than `MIN()' or `MAX()': SELECT c1, SUM(c2) FROM t1 GROUP BY c1; * The columns in the `GROUP BY' clause do not form a leftmost prefix of the index: SELECT c1, c2 FROM t1 GROUP BY c2, c3; * The query refers to a part of a key that comes after the `GROUP BY' part, and for which there is no equality with a constant: SELECT c1, c3 FROM t1 GROUP BY c1, c2; Were the query to include `WHERE c3 = CONST', loose index scan could be used.  File: manual.info, Node: tight-index-scan, Prev: loose-index-scan, Up: group-by-optimization 8.3.1.19 Tight Index Scan ......................... A tight index scan may be either a full index scan or a range index scan, depending on the query conditions. When the conditions for a loose index scan are not met, it still may be possible to avoid creation of temporary tables for `GROUP BY' queries. If there are range conditions in the `WHERE' clause, this method reads only the keys that satisfy these conditions. Otherwise, it performs an index scan. Because this method reads all keys in each range defined by the `WHERE' clause, or scans the whole index if there are no range conditions, we term it a _tight index scan_. With a tight index scan, the grouping operation is performed only after all keys that satisfy the range conditions have been found. For this method to work, it is sufficient that there is a constant equality condition for all columns in a query referring to parts of the key coming before or in between parts of the `GROUP BY' key. The constants from the equality conditions fill in any `gaps' in the search keys so that it is possible to form complete prefixes of the index. These index prefixes then can be used for index lookups. If we require sorting of the `GROUP BY' result, and it is possible to form search keys that are prefixes of the index, MySQL also avoids extra sorting operations because searching with prefixes in an ordered index already retrieves all the keys in order. Assume that there is an index `idx(c1,c2,c3)' on table `t1(c1,c2,c3,c4)'. The following queries do not work with the loose index scan access method described earlier, but still work with the tight index scan access method. * There is a gap in the `GROUP BY', but it is covered by the condition `c2 = 'a'': SELECT c1, c2, c3 FROM t1 WHERE c2 = 'a' GROUP BY c1, c3; * The `GROUP BY' does not begin with the first part of the key, but there is a condition that provides a constant for that part: SELECT c1, c2, c3 FROM t1 WHERE c1 = 'a' GROUP BY c2, c3;  File: manual.info, Node: distinct-optimization, Next: in-subquery-optimization, Prev: group-by-optimization, Up: select-optimization 8.3.1.20 `DISTINCT' Optimization ................................ `DISTINCT' combined with `ORDER BY' needs a temporary table in many cases. Because `DISTINCT' may use `GROUP BY', you should be aware of how MySQL works with columns in `ORDER BY' or `HAVING' clauses that are not part of the selected columns. See *Note group-by-hidden-columns::. In most cases, a `DISTINCT' clause can be considered as a special case of `GROUP BY'. For example, the following two queries are equivalent: SELECT DISTINCT c1, c2, c3 FROM t1 WHERE c1 > CONST; SELECT c1, c2, c3 FROM t1 WHERE c1 > CONST GROUP BY c1, c2, c3; Due to this equivalence, the optimizations applicable to `GROUP BY' queries can be also applied to queries with a `DISTINCT' clause. Thus, for more details on the optimization possibilities for `DISTINCT' queries, see *Note group-by-optimization::. When combining `LIMIT ROW_COUNT' with `DISTINCT', MySQL stops as soon as it finds ROW_COUNT unique rows. If you do not use columns from all tables named in a query, MySQL stops scanning any unused tables as soon as it finds the first match. In the following case, assuming that `t1' is used before `t2' (which you can check with *Note `EXPLAIN': explain.), MySQL stops reading from `t2' (for any particular row in `t1') when it finds the first row in `t2': SELECT DISTINCT t1.a FROM t1, t2 where t1.a=t2.a;  File: manual.info, Node: in-subquery-optimization, Next: limit-optimization, Prev: distinct-optimization, Up: select-optimization 8.3.1.21 Optimizing `IN'/`=ANY' Subqueries .......................................... Certain optimizations are applicable to comparisons that use the `IN' operator to test subquery results (or that use `=ANY', which is equivalent). This section discusses these optimizations, particularly with regard to the challenges that `NULL' values present. Suggestions on what you can do to help the optimizer are given at the end of the discussion. Consider the following subquery comparison: OUTER_EXPR IN (SELECT INNER_EXPR FROM ... WHERE SUBQUERY_WHERE) MySQL evaluates queries `from outside to inside.' That is, it first obtains the value of the outer expression OUTER_EXPR, and then runs the subquery and captures the rows that it produces. A very useful optimization is to `inform' the subquery that the only rows of interest are those where the inner expression INNER_EXPR is equal to OUTER_EXPR. This is done by pushing down an appropriate equality into the subquery's `WHERE' clause. That is, the comparison is converted to this: EXISTS (SELECT 1 FROM ... WHERE SUBQUERY_WHERE AND OUTER_EXPR=INNER_EXPR) After the conversion, MySQL can use the pushed-down equality to limit the number of rows that it must examine when evaluating the subquery. More generally, a comparison of N values to a subquery that returns N-value rows is subject to the same conversion. If OE_I and IE_I represent corresponding outer and inner expression values, this subquery comparison: (OE_1, ..., OE_N) IN (SELECT IE_1, ..., IE_N FROM ... WHERE SUBQUERY_WHERE) Becomes: EXISTS (SELECT 1 FROM ... WHERE SUBQUERY_WHERE AND OE_1 = IE_1 AND ... AND OE_N = IE_N) The following discussion assumes a single pair of outer and inner expression values for simplicity. The conversion just described has its limitations. It is valid only if we ignore possible `NULL' values. That is, the `pushdown' strategy works as long as both of these two conditions are true: * OUTER_EXPR and INNER_EXPR cannot be `NULL'. * You do not need to distinguish `NULL' from `FALSE' subquery results. (If the subquery is a part of an `OR' or `AND' expression in the `WHERE' clause, MySQL assumes that you don't care.) When either or both of those conditions do not hold, optimization is more complex. Suppose that OUTER_EXPR is known to be a non-`NULL' value but the subquery does not produce a row such that OUTER_EXPR = INNER_EXPR. Then `OUTER_EXPR IN (SELECT ...)' evaluates as follows: * `NULL', if the *Note `SELECT': select. produces any row where INNER_EXPR is `NULL' * `FALSE', if the *Note `SELECT': select. produces only non-`NULL' values or produces nothing In this situation, the approach of looking for rows with `OUTER_EXPR = INNER_EXPR' is no longer valid. It is necessary to look for such rows, but if none are found, also look for rows where INNER_EXPR is `NULL'. Roughly speaking, the subquery can be converted to: EXISTS (SELECT 1 FROM ... WHERE SUBQUERY_WHERE AND (OUTER_EXPR=INNER_EXPR OR INNER_EXPR IS NULL)) The need to evaluate the extra `IS NULL' condition is why MySQL has the `ref_or_null' access method: mysql> EXPLAIN -> SELECT OUTER_EXPR IN (SELECT t2.maybe_null_key -> FROM t2, t3 WHERE ...) -> FROM t1; *************************** 1. row *************************** id: 1 select_type: PRIMARY table: t1 ... *************************** 2. row *************************** id: 2 select_type: DEPENDENT SUBQUERY table: t2 type: ref_or_null possible_keys: maybe_null_key key: maybe_null_key key_len: 5 ref: func rows: 2 Extra: Using where; Using index ... The `unique_subquery' and `index_subquery' subquery-specific access methods also have or-null variants. However, they are not visible in *Note `EXPLAIN': explain. output, so you must use *Note `EXPLAIN EXTENDED': explain. followed by *Note `SHOW WARNINGS': show-warnings. (note the `checking NULL' in the warning message): mysql> EXPLAIN EXTENDED -> SELECT OUTER_EXPR IN (SELECT maybe_null_key FROM t2) FROM t1\G *************************** 1. row *************************** id: 1 select_type: PRIMARY table: t1 ... *************************** 2. row *************************** id: 2 select_type: DEPENDENT SUBQUERY table: t2 type: index_subquery possible_keys: maybe_null_key key: maybe_null_key key_len: 5 ref: func rows: 2 Extra: Using index mysql> SHOW WARNINGS\G *************************** 1. row *************************** Level: Note Code: 1003 Message: select (`test`.`t1`.`outer_expr`, (((`test`.`t1`.`outer_expr`) in t2 on maybe_null_key checking NULL))) AS `outer_expr IN (SELECT maybe_null_key FROM t2)` from `test`.`t1` The additional `OR ... IS NULL' condition makes query execution slightly more complicated (and some optimizations within the subquery become inapplicable), but generally this is tolerable. The situation is much worse when OUTER_EXPR can be `NULL'. According to the SQL interpretation of `NULL' as `unknown value,' `NULL IN (SELECT INNER_EXPR ...)' should evaluate to: * `NULL', if the *Note `SELECT': select. produces any rows * `FALSE', if the *Note `SELECT': select. produces no rows For proper evaluation, it is necessary to be able to check whether the *Note `SELECT': select. has produced any rows at all, so `OUTER_EXPR = INNER_EXPR' cannot be pushed down into the subquery. This is a problem, because many real world subqueries become very slow unless the equality can be pushed down. Essentially, there must be different ways to execute the subquery depending on the value of OUTER_EXPR. In MySQL 5.1 before 5.1.16, the optimizer chose speed over distinguishing a `NULL' from `FALSE' result, so for some queries, you might get a `FALSE' result rather than `NULL'. As of MySQL 5.1.16, the optimizer chooses SQL compliance over speed, so it accounts for the possibility that OUTER_EXPR might be `NULL'. If OUTER_EXPR is `NULL', to evaluate the following expression, it is necessary to run the *Note `SELECT': select. to determine whether it produces any rows: NULL IN (SELECT INNER_EXPR FROM ... WHERE SUBQUERY_WHERE) It is necessary to run the original *Note `SELECT': select. here, without any pushed-down equalities of the kind mentioned earlier. On the other hand, when OUTER_EXPR is not `NULL', it is absolutely essential that this comparison: OUTER_EXPR IN (SELECT INNER_EXPR FROM ... WHERE SUBQUERY_WHERE) be converted to this expression that uses a pushed-down condition: EXISTS (SELECT 1 FROM ... WHERE SUBQUERY_WHERE AND OUTER_EXPR=INNER_EXPR) Without this conversion, subqueries will be slow. To solve the dilemma of whether to push down or not push down conditions into the subquery, the conditions are wrapped in `trigger' functions. Thus, an expression of the following form: OUTER_EXPR IN (SELECT INNER_EXPR FROM ... WHERE SUBQUERY_WHERE) is converted into: EXISTS (SELECT 1 FROM ... WHERE SUBQUERY_WHERE AND trigcond(OUTER_EXPR=INNER_EXPR)) More generally, if the subquery comparison is based on several pairs of outer and inner expressions, the conversion takes this comparison: (OE_1, ..., OE_N) IN (SELECT IE_1, ..., IE_N FROM ... WHERE SUBQUERY_WHERE) and converts it to this expression: EXISTS (SELECT 1 FROM ... WHERE SUBQUERY_WHERE AND trigcond(OE_1=IE_1) AND ... AND trigcond(OE_N=IE_N) ) Each `trigcond(X)' is a special function that evaluates to the following values: * X when the `linked' outer expression OE_I is not `NULL' * `TRUE' when the `linked' outer expression OE_I is `NULL' Note that trigger functions are _not_ triggers of the kind that you create with *Note `CREATE TRIGGER': create-trigger. Equalities that are wrapped into `trigcond()' functions are not first class predicates for the query optimizer. Most optimizations cannot deal with predicates that may be turned on and off at query execution time, so they assume any `trigcond(X)' to be an unknown function and ignore it. At the moment, triggered equalities can be used by those optimizations: * Reference optimizations: `trigcond(X=Y [OR Y IS NULL])' can be used to construct `ref', `eq_ref', or `ref_or_null' table accesses. * Index lookup-based subquery execution engines: `trigcond(X=Y)' can be used to construct `unique_subquery' or `index_subquery' accesses. * Table-condition generator: If the subquery is a join of several tables, the triggered condition will be checked as soon as possible. When the optimizer uses a triggered condition to create some kind of index lookup-based access (as for the first two items of the preceding list), it must have a fallback strategy for the case when the condition is turned off. This fallback strategy is always the same: Do a full table scan. In *Note `EXPLAIN': explain. output, the fallback shows up as `Full scan on NULL key' in the `Extra' column: mysql> EXPLAIN SELECT t1.col1, -> t1.col1 IN (SELECT t2.key1 FROM t2 WHERE t2.col2=t1.col2) FROM t1\G *************************** 1. row *************************** id: 1 select_type: PRIMARY table: t1 ... *************************** 2. row *************************** id: 2 select_type: DEPENDENT SUBQUERY table: t2 type: index_subquery possible_keys: key1 key: key1 key_len: 5 ref: func rows: 2 Extra: Using where; Full scan on NULL key If you run *Note `EXPLAIN EXTENDED': explain. followed by *Note `SHOW WARNINGS': show-warnings, you can see the triggered condition: *************************** 1. row *************************** Level: Note Code: 1003 Message: select `test`.`t1`.`col1` AS `col1`, (`test`.`t1`.`col1`, (((`test`.`t1`.`col1`) in t2 on key1 checking NULL where (`test`.`t2`.`col2` = `test`.`t1`.`col2`) having trigcond((`test`.`t2`.`key1`))))) AS `t1.col1 IN (select t2.key1 from t2 where t2.col2=t1.col2)` from `test`.`t1` The use of triggered conditions has some performance implications. A `NULL IN (SELECT ...)' expression now may cause a full table scan (which is slow) when it previously did not. This is the price paid for correct results (the goal of the trigger-condition strategy was to improve compliance and not speed). For multiple-table subqueries, execution of `NULL IN (SELECT ...)' will be particularly slow because the join optimizer doesn't optimize for the case where the outer expression is `NULL'. It assumes that subquery evaluations with `NULL' on the left side are very rare, even if there are statistics that indicate otherwise. On the other hand, if the outer expression might be `NULL' but never actually is, there is no performance penalty. To help the query optimizer better execute your queries, use these tips: * A column must be declared as `NOT NULL' if it really is. (This also helps other aspects of the optimizer.) * If you don't need to distinguish a `NULL' from `FALSE' subquery result, you can easily avoid the slow execution path. Replace a comparison that looks like this: OUTER_EXPR IN (SELECT INNER_EXPR FROM ...) with this expression: (OUTER_EXPR IS NOT NULL) AND (OUTER_EXPR IN (SELECT INNER_EXPR FROM ...)) Then `NULL IN (SELECT ...)' will never be evaluated because MySQL stops evaluating `AND' parts as soon as the expression result is clear.  File: manual.info, Node: limit-optimization, Next: how-to-avoid-table-scan, Prev: in-subquery-optimization, Up: select-optimization 8.3.1.22 `LIMIT' Optimization ............................. In some cases, MySQL handles a query differently when you are using `LIMIT ROW_COUNT' and not using `HAVING': * If you are selecting only a few rows with `LIMIT', MySQL uses indexes in some cases when normally it would prefer to do a full table scan. * If you use `LIMIT ROW_COUNT' with `ORDER BY', MySQL ends the sorting as soon as it has found the first ROW_COUNT rows of the sorted result, rather than sorting the entire result. If ordering is done by using an index, this is very fast. If a filesort must be done, all rows that match the query without the `LIMIT' clause must be selected, and most or all of them must be sorted, before it can be ascertained that the first ROW_COUNT rows have been found. In either case, after the initial rows have been found, there is no need to sort any remainder of the result set, and MySQL does not do so. * When combining `LIMIT ROW_COUNT' with `DISTINCT', MySQL stops as soon as it finds ROW_COUNT unique rows. * In some cases, a `GROUP BY' can be resolved by reading the key in order (or doing a sort on the key) and then calculating summaries until the key value changes. In this case, `LIMIT ROW_COUNT' does not calculate any unnecessary `GROUP BY' values. * As soon as MySQL has sent the required number of rows to the client, it aborts the query unless you are using `SQL_CALC_FOUND_ROWS'. * `LIMIT 0' quickly returns an empty set. This can be useful for checking the validity of a query. When using one of the MySQL APIs, it can also be employed for obtaining the types of the result columns. (This trick does not work in the MySQL Monitor (the *Note `mysql': mysql. program), which merely displays `Empty set' in such cases; you should instead use *Note `SHOW COLUMNS': show-columns. or *Note `DESCRIBE': describe. for this purpose.) * When the server uses temporary tables to resolve the query, it uses the `LIMIT ROW_COUNT' clause to calculate how much space is required.  File: manual.info, Node: how-to-avoid-table-scan, Prev: limit-optimization, Up: select-optimization 8.3.1.23 How to Avoid Table Scans ................................. The output from *Note `EXPLAIN': explain. shows `ALL' in the `type' column when MySQL uses a table scan to resolve a query. This usually happens under the following conditions: * The table is so small that it is faster to perform a table scan than to bother with a key lookup. This is common for tables with fewer than 10 rows and a short row length. * There are no usable restrictions in the `ON' or `WHERE' clause for indexed columns. * You are comparing indexed columns with constant values and MySQL has calculated (based on the index tree) that the constants cover too large a part of the table and that a table scan would be faster. See *Note where-optimizations::. * You are using a key with low cardinality (many rows match the key value) through another column. In this case, MySQL assumes that by using the key it probably will do many key lookups and that a table scan would be faster. For small tables, a table scan often is appropriate and the performance impact is negligible. For large tables, try the following techniques to avoid having the optimizer incorrectly choose a table scan: * Use `ANALYZE TABLE TBL_NAME' to update the key distributions for the scanned table. See *Note analyze-table::. * Use `FORCE INDEX' for the scanned table to tell MySQL that table scans are very expensive compared to using the given index: SELECT * FROM t1, t2 FORCE INDEX (INDEX_FOR_COLUMN) WHERE t1.COL_NAME=t2.COL_NAME; See *Note index-hints::. * Start *Note `mysqld': mysqld. with the `--max-seeks-for-key=1000' option or use `SET max_seeks_for_key=1000' to tell the optimizer to assume that no key scan causes more than 1,000 key seeks. See *Note server-system-variables::.  File: manual.info, Node: non-select-optimization, Next: information-schema-optimization, Prev: select-optimization, Up: statement-optimization 8.3.2 Optimizing Non-`SELECT' Statements ---------------------------------------- * Menu: * insert-speed:: Speed of `INSERT' Statements * update-speed:: Speed of `UPDATE' Statements * delete-speed:: Speed of `DELETE' Statements * repair-table-speed:: Speed of `REPAIR TABLE' Statements  File: manual.info, Node: insert-speed, Next: update-speed, Prev: non-select-optimization, Up: non-select-optimization 8.3.2.1 Speed of `INSERT' Statements .................................... The time required for inserting a row is determined by the following factors, where the numbers indicate approximate proportions: * Connecting: (3) * Sending query to server: (2) * Parsing query: (2) * Inserting row: (1 x size of row) * Inserting indexes: (1 x number of indexes) * Closing: (1) This does not take into consideration the initial overhead to open tables, which is done once for each concurrently running query. The size of the table slows down the insertion of indexes by log N, assuming B-tree indexes. You can use the following methods to speed up inserts: * If you are inserting many rows from the same client at the same time, use *Note `INSERT': insert. statements with multiple `VALUES' lists to insert several rows at a time. This is considerably faster (many times faster in some cases) than using separate single-row *Note `INSERT': insert. statements. If you are adding data to a nonempty table, you can tune the `bulk_insert_buffer_size' variable to make data insertion even faster. See *Note server-system-variables::. * If multiple clients are inserting a lot of rows, you can get higher speed by using the *Note `INSERT DELAYED': insert-delayed. statement. See *Note insert-delayed::. * For a `MyISAM' table, you can use concurrent inserts to add rows at the same time that *Note `SELECT': select. statements are running, if there are no deleted rows in middle of the data file. See *Note concurrent-inserts::. * When loading a table from a text file, use *Note `LOAD DATA INFILE': load-data. This is usually 20 times faster than using *Note `INSERT': insert. statements. See *Note load-data::. * With some extra work, it is possible to make *Note `LOAD DATA INFILE': load-data. run even faster for a `MyISAM' table when the table has many indexes. Use the following procedure: 1. Optionally create the table with *Note `CREATE TABLE': create-table. 2. Execute a *Note `FLUSH TABLES': flush. statement or a *Note `mysqladmin flush-tables': mysqladmin. command. 3. Use *Note `myisamchk --keys-used=0 -rq /PATH/TO/DB/TBL_NAME.': myisamchk. This removes all use of indexes for the table. 4. Insert data into the table with *Note `LOAD DATA INFILE': load-data. This does not update any indexes and therefore is very fast. 5. If you intend only to read from the table in the future, use *Note `myisampack': myisampack. to compress it. See *Note compressed-format::. 6. Re-create the indexes with *Note `myisamchk -rq /PATH/TO/DB/TBL_NAME': myisamchk. This creates the index tree in memory before writing it to disk, which is much faster that updating the index during *Note `LOAD DATA INFILE': load-data. because it avoids lots of disk seeks. The resulting index tree is also perfectly balanced. 7. Execute a *Note `FLUSH TABLES': flush. statement or a *Note `mysqladmin flush-tables': mysqladmin. command. *Note `LOAD DATA INFILE': load-data. performs the preceding optimization automatically if the `MyISAM' table into which you insert data is empty. The main difference between automatic optimization and using the procedure explicitly is that you can let *Note `myisamchk': myisamchk. allocate much more temporary memory for the index creation than you might want the server to allocate for index re-creation when it executes the *Note `LOAD DATA INFILE': load-data. statement. You can also disable or enable the nonunique indexes for a `MyISAM' table by using the following statements rather than *Note `myisamchk': myisamchk. If you use these statements, you can skip the *Note `FLUSH TABLE': flush. operations: ALTER TABLE TBL_NAME DISABLE KEYS; ALTER TABLE TBL_NAME ENABLE KEYS; * To speed up *Note `INSERT': insert. operations that are performed with multiple statements for nontransactional tables, lock your tables: LOCK TABLES a WRITE; INSERT INTO a VALUES (1,23),(2,34),(4,33); INSERT INTO a VALUES (8,26),(6,29); ... UNLOCK TABLES; This benefits performance because the index buffer is flushed to disk only once, after all *Note `INSERT': insert. statements have completed. Normally, there would be as many index buffer flushes as there are *Note `INSERT': insert. statements. Explicit locking statements are not needed if you can insert all rows with a single *Note `INSERT': insert. To obtain faster insertions for transactional tables, you should use *Note `START TRANSACTION': commit. and *Note `COMMIT': commit. instead of *Note `LOCK TABLES': lock-tables. Locking also lowers the total time for multiple-connection tests, although the maximum wait time for individual connections might go up because they wait for locks. Suppose that five clients attempt to perform inserts simultaneously as follows: * Connection 1 does 1000 inserts * Connections 2, 3, and 4 do 1 insert * Connection 5 does 1000 inserts If you do not use locking, connections 2, 3, and 4 finish before 1 and 5. If you use locking, connections 2, 3, and 4 probably do not finish before 1 or 5, but the total time should be about 40% faster. *Note `INSERT': insert, *Note `UPDATE': update, and *Note `DELETE': delete. operations are very fast in MySQL, but you can obtain better overall performance by adding locks around everything that does more than about five successive inserts or updates. If you do very many successive inserts, you could do a *Note `LOCK TABLES': lock-tables. followed by an *Note `UNLOCK TABLES': lock-tables. once in a while (each 1,000 rows or so) to permit other threads to access table. This would still result in a nice performance gain. *Note `INSERT': insert. is still much slower for loading data than *Note `LOAD DATA INFILE': load-data, even when using the strategies just outlined. * To increase performance for `MyISAM' tables, for both *Note `LOAD DATA INFILE': load-data. and *Note `INSERT': insert, enlarge the key cache by increasing the `key_buffer_size' system variable. See *Note server-parameters::.  File: manual.info, Node: update-speed, Next: delete-speed, Prev: insert-speed, Up: non-select-optimization 8.3.2.2 Speed of `UPDATE' Statements .................................... An update statement is optimized like a *Note `SELECT': select. query with the additional overhead of a write. The speed of the write depends on the amount of data being updated and the number of indexes that are updated. Indexes that are not changed do not get updated. Another way to get fast updates is to delay updates and then do many updates in a row later. Performing multiple updates together is much quicker than doing one at a time if you lock the table. For a `MyISAM' table that uses dynamic row format, updating a row to a longer total length may split the row. If you do this often, it is very important to use *Note `OPTIMIZE TABLE': optimize-table. occasionally. See *Note optimize-table::.  File: manual.info, Node: delete-speed, Next: repair-table-speed, Prev: update-speed, Up: non-select-optimization 8.3.2.3 Speed of `DELETE' Statements .................................... The time required to delete individual rows is exactly proportional to the number of indexes. To delete rows more quickly, you can increase the size of the key cache by increasing the `key_buffer_size' system variable. See *Note server-parameters::. To delete all rows from a table, `TRUNCATE TABLE TBL_NAME' is faster than than `DELETE FROM TBL_NAME'. Truncate operations are not transaction-safe; an error occurs when attempting one in the course of an active transaction or active table lock. See *Note truncate-table::.  File: manual.info, Node: repair-table-speed, Prev: delete-speed, Up: non-select-optimization 8.3.2.4 Speed of `REPAIR TABLE' Statements .......................................... *Note `REPAIR TABLE': repair-table. for `MyISAM' tables is similar to using *Note `myisamchk': myisamchk. for repair operations, and some of the same performance optimizations apply: * *Note `myisamchk': myisamchk. has variables that control memory allocation. You may be able to its improve performance by setting these variables, as described in *Note myisamchk-memory::. * For *Note `REPAIR TABLE': repair-table, the same principle applies, but because the repair is done by the server, you set server system variables instead of *Note `myisamchk': myisamchk. variables. Also, In addition to setting memory-allocation variables, increasing the `myisam_max_sort_file_size' system variable increases the likelihood that the repair will use the faster filesort method and avoid the slower repair by key cache method. Set the variable to the maximum file size for your system, after checking to be sure that there is enough free space to hold a copy of the table files. The free space must be available in the file system containing the original table files. Suppose that a *Note `myisamchk': myisamchk. table-repair operation is done using the following options to set its memory-allocation variables: --key_buffer_size=128M --sort_buffer_size=256M --read_buffer_size=64M --write_buffer_size=64M Some of those *Note `myisamchk': myisamchk. variables correspond to server system variables: *Note `myisamchk': myisamchk. System Variable Variable `key_buffer_size' `key_buffer_size' `sort_buffer_size' `myisam_sort_buffer_size' `read_buffer_size' `read_buffer_size' `write_buffer_size' none Each of the server system variables can be set at runtime, and some of them (`myisam_sort_buffer_size', `read_buffer_size') have a session value in addition to a global value. Setting a session value limits the effect of the change to your current session and does not affect other users. Changing a global-only variable (`key_buffer_size', `myisam_max_sort_file_size') affects other users as well. For `key_buffer_size', you must take into account that the buffer is shared with those users. For example, if you set the *Note `myisamchk': myisamchk. `key_buffer_size' variable to 128MB, you could set the corresponding `key_buffer_size' system variable larger than that (if it is not already set larger), to permit key buffer use by activity in other sessions. However, changing the global key buffer size invalidates the buffer, causing increased disk I/O and slowdown for other sessions. An alternative that avoids this problem is to use a separate key cache, assign to it the indexes from the table to be repaired, and deallocate it when the repair is complete. See *Note multiple-key-caches::. Based on the preceding remarks, a *Note `REPAIR TABLE': repair-table. operation can be done as follows to use settings similar to the *Note `myisamchk': myisamchk. command. Here a separate 128MB key buffer is allocated and the file system is assumed to permit a file size of at least 100GB. SET SESSION myisam_sort_buffer_size = 256*1024*1024; SET SESSION read_buffer_size = 64*1024*1024; SET GLOBAL myisam_max_sort_file_size = 100*1024*1024*1024; SET GLOBAL repair_cache.key_buffer_size = 128*1024*1024; CACHE INDEX TBL_NAME IN repair_cache; LOAD INDEX INTO CACHE TBL_NAME; REPAIR TABLE TBL_NAME ; SET GLOBAL repair_cache.key_buffer_size = 0; If you intend to change a global variable but want to do so only for the duration of a *Note `REPAIR TABLE': repair-table. operation to minimally affect other users, save its value in a user variable and restore it afterward. For example: SET @old_myisam_sort_buffer_size = @@global.myisam_max_sort_file_size; SET GLOBAL myisam_max_sort_file_size = 100*1024*1024*1024; REPAIR TABLE tbl_name ; SET GLOBAL myisam_max_sort_file_size = @old_myisam_max_sort_file_size; The system variables that affect *Note `REPAIR TABLE': repair-table. can be set globally at server startup if you want the values to be in effect by default. For example, add these lines to the server `my.cnf' file: [mysqld] myisam_sort_buffer_size=256M key_buffer_size=1G myisam_max_sort_file_size=100G These settings do not include `read_buffer_size'. Setting `read_buffer_size' globally to a large value does so for all sessions and can cause performance to suffer due to excessive memory allocation for a server with many simultaneous sessions.  File: manual.info, Node: information-schema-optimization, Next: miscellaneous-optimization-tips, Prev: non-select-optimization, Up: statement-optimization 8.3.3 `INFORMATION_SCHEMA' Optimization --------------------------------------- As of MySQL 5.1.21, the implementation of `INFORMATION_SCHEMA' is such that certain types of queries for `INFORMATION_SCHEMA' tables can be optimized to execute more quickly. This section provides guidelines on writing queries that take advantage of these optimizations. In general, the strategies outlined here minimize the need for the server to access the file system to obtain the information that makes up the contents of `INFORMATION_SCHEMA' tables. By writing queries that enable the server to avoid directory scans or opening table files, you will obtain better performance. These optimizations do have an effect on how collations are used for searches in `INFORMATION_SCHEMA' tables. For more information, see *Note charset-collation-information-schema::. *1) Try to use constant lookup values for database and table names in the `WHERE' clause* You can take advantage of this principle as follows: * To look up databases or tables, use expressions that evaluate to a constant, such as literal values, functions that return a constant, or scalar subqueries. * Avoid queries that use a nonconstant database name lookup value (or no lookup value) because they require a scan of the data directory to find matching database directory names. * Within a database, avoid queries that use a nonconstant table name lookup value (or no lookup value) because they require a scan of the database directory to find matching table files. This principle applies to the `INFORMATION_SCHEMA' tables shown in the following table, which shows the columns for which a constant lookup value enables the server to avoid a directory scan. For example, if you are selecting from *Note `TABLES': tables-table, using a constant lookup value for `TABLE_SCHEMA' in the `WHERE' clause enables a data directory scan to be avoided. Table Column to specify to Column to specify to avoid data directory avoid database scan directory scan *Note `COLUMNS': `TABLE_SCHEMA' `TABLE_NAME' columns-table. *Note `TABLE_SCHEMA' `TABLE_NAME' `KEY_COLUMN_USAGE': key-column-usage-table. *Note `PARTITIONS': `TABLE_SCHEMA' `TABLE_NAME' partitions-table. *Note `CONSTRAINT_SCHEMA' `TABLE_NAME' `REFERENTIAL_CONSTRAINTS': referential-constraints-table. *Note `STATISTICS': `TABLE_SCHEMA' `TABLE_NAME' statistics-table. *Note `TABLES': `TABLE_SCHEMA' `TABLE_NAME' tables-table. *Note `TABLE_SCHEMA' `TABLE_NAME' `TABLE_CONSTRAINTS': table-constraints-table. *Note `TRIGGERS': `EVENT_OBJECT_SCHEMA' `EVENT_OBJECT_TABLE' triggers-table. *Note `VIEWS': `TABLE_SCHEMA' `TABLE_NAME' views-table. The benefit of a query that is limited to a specific constant database name is that checks need be made only for the named database directory. Example: SELECT TABLE_NAME FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_SCHEMA = 'test'; Use of the literal database name `test' enables the server to check only the `test' database directory, regardless of how many databases there might be. By contrast, the following query is less efficient because it requires a scan of the data directory to determine which database names match the pattern `'test%'': SELECT TABLE_NAME FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_SCHEMA LIKE 'test%'; For a query that is limited to a specific constant table name, checks need be made only for the named table within the corresponding database directory. Example: SELECT TABLE_NAME FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_SCHEMA = 'test' AND TABLE_NAME = 't1'; Use of the literal table name `t1' enables the server to check only the files for the `t1' table, regardless of how many tables there might be in the `test' database. By contrast, the following query requires a scan of the `test' database directory to determine which table names match the pattern `'t%'': SELECT TABLE_NAME FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_SCHEMA = 'test' AND TABLE_NAME LIKE 't%'; The following query requires a scan of the database directory to determine matching database names for the pattern `'test%'', and for each matching database, it requires a scan of the database directory to determine matching table names for the pattern `'t%'': SELECT TABLE_NAME FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_SCHEMA = 'test%' AND TABLE_NAME LIKE 't%'; *2) Write queries that minimize the number of table files that must be opened* For queries that refer to certain `INFORMATION_SCHEMA' table columns, several optimizations are available that minimize the number of table files that must be opened. Example: SELECT TABLE_NAME, ENGINE FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_SCHEMA = 'test'; In this case, after the server has scanned the database directory to determine the names of the tables in the database, those names become available with no further file system lookups. Thus, `TABLE_NAME' requires no files to be opened. The `ENGINE' (storage engine) value can be determined by opening the table's `.frm' file, without touching other table files such as the `.MYD' or `.MYI' file. Some values, such as `INDEX_LENGTH' for `MyISAM' tables, require opening the `.MYD' or `.MYI' file as well. The file-opening optimization types are denoted thus: * `SKIP_OPEN_TABLE': Table files do not need to be opened. The information has already become available within the query by scanning the database directory. * `OPEN_FRM_ONLY': Only the table's `.frm' file need be opened. * `OPEN_TRIGGER_ONLY': Only the table's `.TRG' file need be opened. * `OPEN_FULL_TABLE': The unoptimized information lookup. The `.frm', `.MYD', and `.MYI' files must be opened. The following list indicates how the preceding optimization types apply to `INFORMATION_SCHEMA' table columns. For tables and columns not named, none of the optimizations apply. * *Note `COLUMNS': columns-table.: `OPEN_FRM_ONLY' applies to all columns * *Note `KEY_COLUMN_USAGE': key-column-usage-table.: `OPEN_FULL_TABLE' applies to all columns * *Note `PARTITIONS': partitions-table.: `OPEN_FULL_TABLE' applies to all columns * *Note `REFERENTIAL_CONSTRAINTS': referential-constraints-table.: `OPEN_FULL_TABLE' applies to all columns * *Note `STATISTICS': statistics-table.: Column Optimization type `TABLE_CATALOG' `OPEN_FRM_ONLY' `TABLE_SCHEMA' `OPEN_FRM_ONLY' `TABLE_NAME' `OPEN_FRM_ONLY' `NON_UNIQUE' `OPEN_FRM_ONLY' `INDEX_SCHEMA' `OPEN_FRM_ONLY' `INDEX_NAME' `OPEN_FRM_ONLY' `SEQ_IN_INDEX' `OPEN_FRM_ONLY' `COLUMN_NAME' `OPEN_FRM_ONLY' `COLLATION' `OPEN_FRM_ONLY' `CARDINALITY' `OPEN_FULL_TABLE' `SUB_PART' `OPEN_FRM_ONLY' `PACKED' `OPEN_FRM_ONLY' `NULLABLE' `OPEN_FRM_ONLY' `INDEX_TYPE' `OPEN_FULL_TABLE' `COMMENT' `OPEN_FRM_ONLY' * *Note `TABLES': tables-table.: Column Optimization type `TABLE_CATALOG' `SKIP_OPEN_TABLE' `TABLE_SCHEMA' `SKIP_OPEN_TABLE' `TABLE_NAME' `SKIP_OPEN_TABLE' `TABLE_TYPE' `OPEN_FRM_ONLY' `ENGINE' `OPEN_FRM_ONLY' `VERSION' `OPEN_FRM_ONLY' `ROW_FORMAT' `OPEN_FULL_TABLE' `TABLE_ROWS' `OPEN_FULL_TABLE' `AVG_ROW_LENGTH' `OPEN_FULL_TABLE' `DATA_LENGTH' `OPEN_FULL_TABLE' `MAX_DATA_LENGTH' `OPEN_FULL_TABLE' `INDEX_LENGTH' `OPEN_FULL_TABLE' `DATA_FREE' `OPEN_FULL_TABLE' `AUTO_INCREMENT' `OPEN_FULL_TABLE' `CREATE_TIME' `OPEN_FULL_TABLE' `UPDATE_TIME' `OPEN_FULL_TABLE' `CHECK_TIME' `OPEN_FULL_TABLE' `TABLE_COLLATION' `OPEN_FRM_ONLY' `CHECKSUM' `OPEN_FULL_TABLE' `CREATE_OPTIONS' `OPEN_FRM_ONLY' `TABLE_COMMENT' `OPEN_FRM_ONLY' * *Note `TABLE_CONSTRAINTS': table-constraints-table.: `OPEN_FULL_TABLE' applies to all columns * *Note `TRIGGERS': triggers-table.: `OPEN_FULL_TABLE' applies to all columns * *Note `VIEWS': views-table.: Column Optimization type `TABLE_CATALOG' `OPEN_FRM_ONLY' `TABLE_SCHEMA' `OPEN_FRM_ONLY' `TABLE_NAME' `OPEN_FRM_ONLY' `VIEW_DEFINITION' `OPEN_FULL_TABLE' `CHECK_OPTION' `OPEN_FULL_TABLE' `IS_UPDATABLE' `OPEN_FULL_TABLE' `DEFINER' `OPEN_FULL_TABLE' `SECURITY_TYPE' `OPEN_FULL_TABLE' `CHARACTER_SET_CLIENT' `OPEN_FULL_TABLE' `COLLATION_CONNECTION' `OPEN_FULL_TABLE' *3) Use *Note `EXPLAIN': explain. to determine whether the server can use `INFORMATION_SCHEMA' optimizations for a query* This applies particularly for `INFORMATION_SCHEMA' queries that search for information from more than one database, which might take a long time and impact performance. The `Extra' value in *Note `EXPLAIN': explain. output indicates which, if any, of the optimizations described earlier the server can use to evaluate `INFORMATION_SCHEMA' queries. The following examples demonstrate the kinds of information you can expect to see in the `Extra' value. mysql> EXPLAIN SELECT TABLE_NAME FROM INFORMATION_SCHEMA.VIEWS WHERE -> TABLE_SCHEMA = 'test' AND TABLE_NAME = 'v1'\G *************************** 1. row *************************** id: 1 select_type: SIMPLE table: VIEWS type: ALL possible_keys: NULL key: TABLE_SCHEMA,TABLE_NAME key_len: NULL ref: NULL rows: NULL Extra: Using where; Open_frm_only; Scanned 0 databases Use of constant database and table lookup values enables the server to avoid directory scans. For references to `VIEWS.TABLE_NAME', only the `.frm' file need be opened. mysql> EXPLAIN SELECT TABLE_NAME, ROW_FORMAT FROM INFORMATION_SCHEMA.TABLES\G *************************** 1. row *************************** id: 1 select_type: SIMPLE table: TABLES type: ALL possible_keys: NULL key: NULL key_len: NULL ref: NULL rows: NULL Extra: Open_full_table; Scanned all databases No lookup values are provided (there is no `WHERE' clause), so the server must scan the data directory and each database directory. For each table thus identified, the table name and row format are selected. `TABLE_NAME' requires no further table files to be opened (the `SKIP_OPEN_TABLE' optimization applies). `ROW_FORMAT' requires all table files to be opened (`OPEN_FULL_TABLE' applies). *Note `EXPLAIN': explain. reports `OPEN_FULL_TABLE' because it is more expensive than `SKIP_OPEN_TABLE'. mysql> EXPLAIN SELECT TABLE_NAME, TABLE_TYPE FROM INFORMATION_SCHEMA.TABLES -> WHERE TABLE_SCHEMA = 'test'\G *************************** 1. row *************************** id: 1 select_type: SIMPLE table: TABLES type: ALL possible_keys: NULL key: TABLE_SCHEMA key_len: NULL ref: NULL rows: NULL Extra: Using where; Open_frm_only; Scanned 1 database No table name lookup value is provided, so the server must scan the `test' database directory. For the `TABLE_NAME' and `TABLE_TYPE' columns, the `SKIP_OPEN_TABLE' and `OPEN_FRM_ONLY' optimizations apply, respectively. *Note `EXPLAIN': explain. reports `OPEN_FRM_ONLY' because it is more expensive. mysql> EXPLAIN SELECT B.TABLE_NAME -> FROM INFORMATION_SCHEMA.TABLES AS A, INFORMATION_SCHEMA.COLUMNS AS B -> WHERE A.TABLE_SCHEMA = 'test' -> AND A.TABLE_NAME = 't1' -> AND B.TABLE_NAME = A.TABLE_NAME\G *************************** 1. row *************************** id: 1 select_type: SIMPLE table: A type: ALL possible_keys: NULL key: TABLE_SCHEMA,TABLE_NAME key_len: NULL ref: NULL rows: NULL Extra: Using where; Skip_open_table; Scanned 0 databases *************************** 2. row *************************** id: 1 select_type: SIMPLE table: B type: ALL possible_keys: NULL key: NULL key_len: NULL ref: NULL rows: NULL Extra: Using where; Open_frm_only; Scanned all databases; Using join buffer For the first *Note `EXPLAIN': explain. output row: Constant database and table lookup values enable the server to avoid directory scans for `TABLES' values. References to `TABLES.TABLE_NAME' require no further table files. For the second *Note `EXPLAIN': explain. output row: All *Note `COLUMNS': columns-table. table values are `OPEN_FRM_ONLY' lookups, so `COLUMNS.TABLE_NAME' requires the `.frm' file to be opened. mysql> EXPLAIN SELECT * FROM INFORMATION_SCHEMA.COLLATIONS\G *************************** 1. row *************************** id: 1 select_type: SIMPLE table: COLLATIONS type: ALL possible_keys: NULL key: NULL key_len: NULL ref: NULL rows: NULL Extra: In this case, no optimizations apply because *Note `COLLATIONS': collations-table. is not one of the `INFORMATION_SCHEMA' tables for which optimizations are available.  File: manual.info, Node: miscellaneous-optimization-tips, Prev: information-schema-optimization, Up: statement-optimization 8.3.4 Other Optimization Tips ----------------------------- This section lists a number of miscellaneous tips for improving query processing speed: * Use persistent connections to the database to avoid connection overhead. If you cannot use persistent connections and you are initiating many new connections to the database, you may want to change the value of the `thread_cache_size' variable. See *Note server-parameters::. * Always check whether all your queries really use the indexes that you have created in the tables. In MySQL, you can do this with the *Note `EXPLAIN': explain. statement. See *Note using-explain::. * Try to avoid complex *Note `SELECT': select. queries on `MyISAM' tables that are updated frequently, to avoid problems with table locking that occur due to contention between readers and writers. * `MyISAM' supports concurrent inserts: If a table has no free blocks in the middle of the data file, you can *Note `INSERT': insert. new rows into it at the same time that other threads are reading from the table. If it is important to be able to do this, you should consider using the table in ways that avoid deleting rows. Another possibility is to run *Note `OPTIMIZE TABLE': optimize-table. to defragment the table after you have deleted a lot of rows from it. This behavior is altered by setting the `concurrent_insert' variable. You can force new rows to be appended (and therefore permit concurrent inserts), even in tables that have deleted rows. See *Note concurrent-inserts::. * To fix any compression issues that may have occurred with `ARCHIVE' tables, you can use *Note `OPTIMIZE TABLE': optimize-table. See *Note archive-storage-engine::. * Use `ALTER TABLE ... ORDER BY EXPR1, EXPR2, ...' if you usually retrieve rows in `EXPR1, EXPR2, ...' order. By using this option after extensive changes to the table, you may be able to get higher performance. * In some cases, it may make sense to introduce a column that is `hashed' based on information from other columns. If this column is short, reasonably unique, and indexed, it may be much faster than a `wide' index on many columns. In MySQL, it is very easy to use this extra column: SELECT * FROM TBL_NAME WHERE HASH_COL=MD5(CONCAT(COL1,COL2)) AND COL1='CONSTANT' AND COL2='CONSTANT'; * For `MyISAM' tables that change frequently, you should try to avoid all variable-length columns (*Note `VARCHAR': char, *Note `BLOB': blob, and *Note `TEXT': blob.). The table uses dynamic row format if it includes even a single variable-length column. See *Note storage-engines::. * It is normally not useful to split a table into different tables just because the rows become large. In accessing a row, the biggest performance hit is the disk seek needed to find the first byte of the row. After finding the data, most modern disks can read the entire row fast enough for most applications. The only cases where splitting up a table makes an appreciable difference is if it is a `MyISAM' table using dynamic row format that you can change to a fixed row size, or if you very often need to scan the table but do not need most of the columns. See *Note storage-engines::. * If you often need to calculate results such as counts based on information from a lot of rows, it may be preferable to introduce a new table and update the counter in real time. An update of the following form is very fast: UPDATE TBL_NAME SET COUNT_COL=COUNT_COL+1 WHERE KEY_COL=CONSTANT; This is very important when you use MySQL storage engines such as `MyISAM' that has only table-level locking (multiple readers with single writers). This also gives better performance with most database systems, because the row locking manager in this case has less to do. * If you need to collect statistics from large log tables, use summary tables instead of scanning the entire log table. Maintaining the summaries should be much faster than trying to calculate statistics `live.' Regenerating new summary tables from the logs when things change (depending on business decisions) is faster than changing the running application. * If possible, you should classify reports as `live' or as `statistical,' where data needed for statistical reports is created only from summary tables that are generated periodically from the live data. * Take advantage of the fact that columns have default values. Insert values explicitly only when the value to be inserted differs from the default. This reduces the parsing that MySQL must do and improves the insert speed. * In some cases, it is convenient to pack and store data into a *Note `BLOB': blob. column. In this case, you must provide code in your application to pack and unpack information, but this may save a lot of accesses at some stage. This is practical when you have data that does not conform well to a rows-and-columns table structure. * Normally, you should try to keep all data nonredundant (observing what is referred to in database theory as _third normal form_). However, there may be situations in which it can be advantageous to duplicate information or create summary tables to gain more speed. * Stored routines or UDFs (user-defined functions) may be a good way to gain performance for some tasks. See *Note stored-routines::, and *Note adding-functions::, for more information. * You can increase performance by caching queries or answers in your application and then executing many inserts or updates together. If your database system supports table locks, this should help to ensure that the index cache is only flushed once after all updates. You can also take advantage of MySQL's query cache to achieve similar results; see *Note query-cache::. * Use *Note `INSERT DELAYED': insert-delayed. when you do not need to know when your data is written. This reduces the overall insertion impact because many rows can be written with a single disk write. * Use `INSERT LOW_PRIORITY' when you want to give *Note `SELECT': select. statements higher priority than your inserts. Use `SELECT HIGH_PRIORITY' to get retrievals that jump the queue. That is, the *Note `SELECT': select. is executed even if there is another client waiting to do a write. `LOW_PRIORITY' and `HIGH_PRIORITY' have an effect only for storage engines that use only table-level locking (such as `MyISAM', `MEMORY', and `MERGE'). * Use multiple-row *Note `INSERT': insert. statements to store many rows with one SQL statement. Many SQL servers support this, including MySQL. * Use *Note `LOAD DATA INFILE': load-data. to load large amounts of data. This is faster than using *Note `INSERT': insert. statements. * Use `AUTO_INCREMENT' columns so that each row in a table can be identified by a single unique value. unique values. * Use *Note `OPTIMIZE TABLE': optimize-table. once in a while to avoid fragmentation with dynamic-format `MyISAM' tables. See *Note myisam-table-formats::. * Use `MEMORY' tables when possible to get more speed. See *Note memory-storage-engine::. `MEMORY' tables are useful for noncritical data that is accessed often, such as information about the last displayed banner for users who don't have cookies enabled in their Web browser. User sessions are another alternative available in many Web application environments for handling volatile state data. * With Web servers, images and other binary assets should normally be stored as files. That is, store only a reference to the file rather than the file itself in the database. Most Web servers are better at caching files than database contents, so using files is generally faster. * Columns with identical information in different tables should be declared to have identical data types so that joins based on the corresponding columns will be faster. * Try to keep column names simple. For example, in a table named `customer', use a column name of `name' instead of `customer_name'. To make your names portable to other SQL servers, you should keep them shorter than 18 characters. * If you need really high speed, you should take a look at the low-level interfaces for data storage that the different SQL servers support. For example, by accessing the MySQL `MyISAM' storage engine directly, you could get a speed increase of two to five times compared to using the SQL interface. To be able to do this, the data must be on the same server as the application, and usually it should only be accessed by one process (because external file locking is really slow). One could eliminate these problems by introducing low-level `MyISAM' commands in the MySQL server (this could be one easy way to get more performance if needed). By carefully designing the database interface, it should be quite easy to support this type of optimization. * If you are using numeric data, it is faster in many cases to access information from a database (using a live connection) than to access a text file. Information in the database is likely to be stored in a more compact format than in the text file, so accessing it involves fewer disk accesses. You also save code in your application because you need not parse your text files to find line and column boundaries. * Replication can provide a performance benefit for some operations. You can distribute client retrievals among replication servers to split up the load. To avoid slowing down the master while making backups, you can make backups using a slave server. See *Note replication::. * Declaring a `MyISAM' table with the `DELAY_KEY_WRITE=1' table option makes index updates faster because they are not flushed to disk until the table is closed. The downside is that if something kills the server while such a table is open, you should ensure that the table is okay by running the server with the `--myisam-recover' option, or by running *Note `myisamchk': myisamchk. before restarting the server. (However, even in this case, you should not lose anything by using `DELAY_KEY_WRITE', because the key information can always be generated from the data rows.)  File: manual.info, Node: controlling-optimizer, Next: optimization-indexes, Prev: statement-optimization, Up: optimization 8.4 Controlling the Query Optimizer =================================== * Menu: * controlling-query-plan-evaluation:: Controlling Query Plan Evaluation * switchable-optimizations:: Controlling Switchable Optimizations MySQL provides optimizer control through system variables that affect how query plans are evaluated and which switchable optimizations are enabled.  File: manual.info, Node: controlling-query-plan-evaluation, Next: switchable-optimizations, Prev: controlling-optimizer, Up: controlling-optimizer 8.4.1 Controlling Query Plan Evaluation --------------------------------------- The task of the query optimizer is to find an optimal plan for executing an SQL query. Because the difference in performance between `good' and `bad' plans can be orders of magnitude (that is, seconds versus hours or even days), most query optimizers, including that of MySQL, perform a more or less exhaustive search for an optimal plan among all possible query evaluation plans. For join queries, the number of possible plans investigated by the MySQL optimizer grows exponentially with the number of tables referenced in a query. For small numbers of tables (typically less than 7 to 10) this is not a problem. However, when larger queries are submitted, the time spent in query optimization may easily become the major bottleneck in the server's performance. A more flexible method for query optimization enables the user to control how exhaustive the optimizer is in its search for an optimal query evaluation plan. The general idea is that the fewer plans that are investigated by the optimizer, the less time it spends in compiling a query. On the other hand, because the optimizer skips some plans, it may miss finding an optimal plan. The behavior of the optimizer with respect to the number of plans it evaluates can be controlled using two system variables: * The `optimizer_prune_level' variable tells the optimizer to skip certain plans based on estimates of the number of rows accessed for each table. Our experience shows that this kind of `educated guess' rarely misses optimal plans, and may dramatically reduce query compilation times. That is why this option is on (`optimizer_prune_level=1') by default. However, if you believe that the optimizer missed a better query plan, this option can be switched off (`optimizer_prune_level=0') with the risk that query compilation may take much longer. Note that, even with the use of this heuristic, the optimizer still explores a roughly exponential number of plans. * The `optimizer_search_depth' variable tells how far into the `future' of each incomplete plan the optimizer should look to evaluate whether it should be expanded further. Smaller values of `optimizer_search_depth' may result in orders of magnitude smaller query compilation times. For example, queries with 12, 13, or more tables may easily require hours and even days to compile if `optimizer_search_depth' is close to the number of tables in the query. At the same time, if compiled with `optimizer_search_depth' equal to 3 or 4, the optimizer may compile in less than a minute for the same query. If you are unsure of what a reasonable value is for `optimizer_search_depth', this variable can be set to 0 to tell the optimizer to determine the value automatically.  File: manual.info, Node: switchable-optimizations, Prev: controlling-query-plan-evaluation, Up: controlling-optimizer 8.4.2 Controlling Switchable Optimizations ------------------------------------------ The `optimizer_switch' system variable enables control over optimizer behavior. Its value is a set of flags, each of which has a value of `on' or `off' to indicate whether the corresponding optimizer behavior is enabled or disabled. This variable has global and session values and can be changed at runtime. The global default can be set at server startup. To see the current set of optimizer flags, select the variable value: mysql> SELECT @@optimizer_switch\G *************************** 1. row *************************** @@optimizer_switch: index_merge=on,index_merge_union=on, index_merge_sort_union=on, index_merge_intersection=on To change the value of `optimizer_switch', assign a value consisting of a comma-separated list of one or more commands: SET [GLOBAL|SESSION] optimizer_switch='COMMAND[,COMMAND]...'; Each COMMAND value should have one of the forms shown in the following table. Command Syntax Meaning `default' Reset every optimization to its default value `OPT_NAME=default' Set the named optimization to its default value `OPT_NAME=off' Disable the named optimization `OPT_NAME=on' Enable the named optimization The order of the commands in the value does not matter, although the `default' command is executed first if present. Setting an OPT_NAME flag to `default' sets it to whichever of `on' or `off' is its default value. Specifying any given OPT_NAME more than once in the value is not permitted and causes an error. Any errors in the value cause the assignment to fail with an error and the value of `optimizer_switch' remains unchanged. The following table lists the permissible OPT_NAME flag names. Flag Name Meaning `index_merge' Controls all Index Merge optimizations `index_merge_intersection'Controls the Index Merge Intersection Access optimization `index_merge_sort_union' Controls the Index Merge Sort-Union Access optimization `index_merge_union' Controls the Index Merge Union Access optimization For information about Index Merge, see *Note index-merge-optimization::. When you assign a value to `optimizer_switch', flags that are not mentioned keep their current values. This makes it possible to enable or disable specific optimizer behaviors in a single statement without affecting other behaviors. The statement does not depend on what other optimizer flags exist and what their values are. Suppose that all Index Merge optimizations are enabled: mysql> SELECT @@optimizer_switch\G *************************** 1. row *************************** @@optimizer_switch: index_merge=on,index_merge_union=on, index_merge_sort_union=on, index_merge_intersection=on If the server is using the Index Merge Union or Index Merge Sort-Union access methods for certain queries and you want to check whether the optimizer will perform better without them, set the variable value like this: mysql> SET optimizer_switch='index_merge_union=off,index_merge_sort_union=off'; mysql> SELECT @@optimizer_switch\G *************************** 1. row *************************** @@optimizer_switch: index_merge=on,index_merge_union=off, index_merge_sort_union=off, index_merge_intersection=on  File: manual.info, Node: optimization-indexes, Next: buffering-caching, Prev: controlling-optimizer, Up: optimization 8.5 Optimization and Indexes ============================ * Menu: * column-indexes:: Column Indexes * multiple-column-indexes:: Multiple-Column Indexes * mysql-indexes:: How MySQL Uses Indexes * myisam-index-statistics:: `MyISAM' Index Statistics Collection  File: manual.info, Node: column-indexes, Next: multiple-column-indexes, Prev: optimization-indexes, Up: optimization-indexes 8.5.1 Column Indexes -------------------- All MySQL data types can be indexed. Use of indexes on the relevant columns is the best way to improve the performance of *Note `SELECT': select. operations. The maximum number of indexes per table and the maximum index length is defined per storage engine. See *Note storage-engines::. All storage engines support at least 16 indexes per table and a total index length of at least 256 bytes. Most storage engines have higher limits. With `COL_NAME(N)' syntax in an index specification, you can create an index that uses only the first N characters of a string column. Indexing only a prefix of column values in this way can make the index file much smaller. When you index a *Note `BLOB': blob. or *Note `TEXT': blob. column, you _must_ specify a prefix length for the index. For example: CREATE TABLE test (blob_col BLOB, INDEX(blob_col(10))); Prefixes can be up to 1000 bytes long (767 bytes for `InnoDB' tables). Note that prefix limits are measured in bytes, whereas the prefix length in *Note `CREATE TABLE': create-table. statements is interpreted as number of characters. _Be sure to take this into account when specifying a prefix length for a column that uses a multi-byte character set_. You can also create `FULLTEXT' indexes. These are used for full-text searches. Only the `MyISAM' storage engine supports `FULLTEXT' indexes and only for *Note `CHAR': char, *Note `VARCHAR': char, and *Note `TEXT': blob. columns. Indexing always takes place over the entire column and column prefix indexing is not supported. For details, see *Note fulltext-search::. You can also create indexes on spatial data types. Currently, only `MyISAM' supports R-tree indexes on spatial types. Other storage engines use B-trees for indexing spatial types (except for `ARCHIVE' and *Note `NDBCLUSTER': mysql-cluster, which do not support spatial type indexing). The `MEMORY' storage engine uses `HASH' indexes by default, but also supports `BTREE' indexes.  File: manual.info, Node: multiple-column-indexes, Next: mysql-indexes, Prev: column-indexes, Up: optimization-indexes 8.5.2 Multiple-Column Indexes ----------------------------- MySQL can create composite indexes (that is, indexes on multiple columns). An index may consist of up to 16 columns. For certain data types, you can index a prefix of the column (see *Note column-indexes::). A multiple-column index can be considered a sorted array containing values that are created by concatenating the values of the indexed columns. MySQL uses multiple-column indexes in such a way that queries are fast when you specify a known quantity for the first column of the index in a `WHERE' clause, even if you do not specify values for the other columns. Suppose that a table has the following specification: CREATE TABLE test ( id INT NOT NULL, last_name CHAR(30) NOT NULL, first_name CHAR(30) NOT NULL, PRIMARY KEY (id), INDEX name (last_name,first_name) ); The `name' index is an index over the `last_name' and `first_name' columns. The index can be used for queries that specify values in a known range for `last_name', or for both `last_name' and `first_name'. Therefore, the `name' index is used in the following queries: SELECT * FROM test WHERE last_name='Widenius'; SELECT * FROM test WHERE last_name='Widenius' AND first_name='Michael'; SELECT * FROM test WHERE last_name='Widenius' AND (first_name='Michael' OR first_name='Monty'); SELECT * FROM test WHERE last_name='Widenius' AND first_name >='M' AND first_name < 'N'; However, the `name' index is _not_ used in the following queries: SELECT * FROM test WHERE first_name='Michael'; SELECT * FROM test WHERE last_name='Widenius' OR first_name='Michael'; The manner in which MySQL uses indexes to improve query performance is discussed further in *Note mysql-indexes::.  File: manual.info, Node: mysql-indexes, Next: myisam-index-statistics, Prev: multiple-column-indexes, Up: optimization-indexes 8.5.3 How MySQL Uses Indexes ---------------------------- Indexes are used to find rows with specific column values quickly. Without an index, MySQL must begin with the first row and then read through the entire table to find the relevant rows. The larger the table, the more this costs. If the table has an index for the columns in question, MySQL can quickly determine the position to seek to in the middle of the data file without having to look at all the data. If a table has 1,000 rows, this is at least 100 times faster than reading sequentially. If you need to access most of the rows, it is faster to read sequentially, because this minimizes disk seeks. Most MySQL indexes (`PRIMARY KEY', `UNIQUE', `INDEX', and `FULLTEXT') are stored in B-trees. Exceptions are that indexes on spatial data types use R-trees, and that `MEMORY' tables also support hash indexes. Strings are automatically prefix- and end-space compressed. See *Note create-index::. In general, indexes are used as described in the following discussion. Characteristics specific to hash indexes (as used in `MEMORY' tables) are described at the end of this section. MySQL uses indexes for these operations: * To find the rows matching a `WHERE' clause quickly. * To eliminate rows from consideration. If there is a choice between multiple indexes, MySQL normally uses the index that finds the smallest number of rows. * To retrieve rows from other tables when performing joins. MySQL can use indexes on columns more efficiently if they are declared as the same type and size. In this context, *Note `VARCHAR': char. and *Note `CHAR': char. are considered the same if they are declared as the same size. For example, `VARCHAR(10)' and `CHAR(10)' are the same size, but `VARCHAR(10)' and `CHAR(15)' are not. Comparison of dissimilar columns may prevent use of indexes if values cannot be compared directly without conversion. Suppose that a numeric column is compared to a string column. For a given value such as `1' in the numeric column, it might compare equal to any number of values in the string column such as `'1'', `' 1'', `'00001'', or `'01.e1''. This rules out use of any indexes for the string column. * To find the `MIN()' or `MAX()' value for a specific indexed column KEY_COL. This is optimized by a preprocessor that checks whether you are using `WHERE KEY_PART_N = CONSTANT' on all key parts that occur before KEY_COL in the index. In this case, MySQL does a single key lookup for each `MIN()' or `MAX()' expression and replaces it with a constant. If all expressions are replaced with constants, the query returns at once. For example: SELECT MIN(KEY_PART2),MAX(KEY_PART2) FROM TBL_NAME WHERE KEY_PART1=10; * To sort or group a table if the sorting or grouping is done on a leftmost prefix of a usable key (for example, `ORDER BY KEY_PART1, KEY_PART2'). If all key parts are followed by `DESC', the key is read in reverse order. See *Note order-by-optimization::, and *Note group-by-optimization::. * In some cases, a query can be optimized to retrieve values without consulting the data rows. If a query uses only columns from a table that are numeric and that form a leftmost prefix for some key, the selected values may be retrieved from the index tree for greater speed: SELECT KEY_PART3 FROM TBL_NAME WHERE KEY_PART1=1 Suppose that you issue the following *Note `SELECT': select. statement: mysql> SELECT * FROM TBL_NAME WHERE col1=VAL1 AND col2=VAL2; If a multiple-column index exists on `col1' and `col2', the appropriate rows can be fetched directly. If separate single-column indexes exist on `col1' and `col2', the optimizer will attempt to use the Index Merge optimization (see *Note index-merge-optimization::), or attempt to find the most restrictive index by deciding which index finds fewer rows and using that index to fetch the rows. If the table has a multiple-column index, any leftmost prefix of the index can be used by the optimizer to find rows. For example, if you have a three-column index on `(col1, col2, col3)', you have indexed search capabilities on `(col1)', `(col1, col2)', and `(col1, col2, col3)'. MySQL cannot use an index if the columns do not form a leftmost prefix of the index. Suppose that you have the *Note `SELECT': select. statements shown here: SELECT * FROM TBL_NAME WHERE col1=VAL1; SELECT * FROM TBL_NAME WHERE col1=VAL1 AND col2=VAL2; SELECT * FROM TBL_NAME WHERE col2=VAL2; SELECT * FROM TBL_NAME WHERE col2=VAL2 AND col3=VAL3; If an index exists on `(col1, col2, col3)', only the first two queries use the index. The third and fourth queries do involve indexed columns, but `(col2)' and `(col2, col3)' are not leftmost prefixes of `(col1, col2, col3)'. * B-Tree Index Characteristics * A B-tree index can be used for column comparisons in expressions that use the `=', `>', `>=', `<', `<=', or `BETWEEN' operators. The index also can be used for `LIKE' comparisons if the argument to `LIKE' is a constant string that does not start with a wildcard character. For example, the following *Note `SELECT': select. statements use indexes: SELECT * FROM TBL_NAME WHERE KEY_COL LIKE 'Patrick%'; SELECT * FROM TBL_NAME WHERE KEY_COL LIKE 'Pat%_ck%'; In the first statement, only rows with `'Patrick' <= KEY_COL < 'Patricl'' are considered. In the second statement, only rows with `'Pat' <= KEY_COL < 'Pau'' are considered. The following *Note `SELECT': select. statements do not use indexes: SELECT * FROM TBL_NAME WHERE KEY_COL LIKE '%Patrick%'; SELECT * FROM TBL_NAME WHERE KEY_COL LIKE OTHER_COL; In the first statement, the `LIKE' value begins with a wildcard character. In the second statement, the `LIKE' value is not a constant. If you use `... LIKE '%STRING%'' and STRING is longer than three characters, MySQL uses the _Turbo Boyer-Moore algorithm_ to initialize the pattern for the string and then uses this pattern to perform the search more quickly. A search using `COL_NAME IS NULL' employs indexes if COL_NAME is indexed. Any index that does not span all `AND' levels in the `WHERE' clause is not used to optimize the query. In other words, to be able to use an index, a prefix of the index must be used in every `AND' group. The following `WHERE' clauses use indexes: ... WHERE INDEX_PART1=1 AND INDEX_PART2=2 AND OTHER_COLUMN=3 /* INDEX = 1 OR INDEX = 2 */ ... WHERE INDEX=1 OR A=10 AND INDEX=2 /* optimized like "INDEX_PART1='hello'" */ ... WHERE INDEX_PART1='hello' AND INDEX_PART3=5 /* Can use index on INDEX1 but not on INDEX2 or INDEX3 */ ... WHERE INDEX1=1 AND INDEX2=2 OR INDEX1=3 AND INDEX3=3; These `WHERE' clauses do _not_ use indexes: /* INDEX_PART1 is not used */ ... WHERE INDEX_PART2=1 AND INDEX_PART3=2 /* Index is not used in both parts of the WHERE clause */ ... WHERE INDEX=1 OR A=10 /* No index spans all rows */ ... WHERE INDEX_PART1=1 OR INDEX_PART2=10 Sometimes MySQL does not use an index, even if one is available. One circumstance under which this occurs is when the optimizer estimates that using the index would require MySQL to access a very large percentage of the rows in the table. (In this case, a table scan is likely to be much faster because it requires fewer seeks.) However, if such a query uses `LIMIT' to retrieve only some of the rows, MySQL uses an index anyway, because it can much more quickly find the few rows to return in the result. * Hash Index Characteristics * Hash indexes have somewhat different characteristics from those just discussed: * They are used only for equality comparisons that use the `=' or `<=>' operators (but are _very_ fast). They are not used for comparison operators such as `<' that find a range of values. * The optimizer cannot use a hash index to speed up `ORDER BY' operations. (This type of index cannot be used to search for the next entry in order.) * MySQL cannot determine approximately how many rows there are between two values (this is used by the range optimizer to decide which index to use). This may affect some queries if you change a `MyISAM' table to a hash-indexed `MEMORY' table. * Only whole keys can be used to search for a row. (With a B-tree index, any leftmost prefix of the key can be used to find rows.)  File: manual.info, Node: myisam-index-statistics, Prev: mysql-indexes, Up: optimization-indexes 8.5.4 `MyISAM' Index Statistics Collection ------------------------------------------ Storage engines collect statistics about tables for use by the optimizer. Table statistics are based on value groups, where a value group is a set of rows with the same key prefix value. For optimizer purposes, an important statistic is the average value group size. MySQL uses the average value group size in the following ways: * To estimate how may rows must be read for each `ref' access * To estimate how many row a partial join will produce; that is, the number of rows that an operation of this form will produce: (...) JOIN TBL_NAME ON TBL_NAME.KEY = EXPR As the average value group size for an index increases, the index is less useful for those two purposes because the average number of rows per lookup increases: For the index to be good for optimization purposes, it is best that each index value target a small number of rows in the table. When a given index value yields a large number of rows, the index is less useful and MySQL is less likely to use it. The average value group size is related to table cardinality, which is the number of value groups. The *Note `SHOW INDEX': show-index. statement displays a cardinality value based on N/S, where N is the number of rows in the table and S is the average value group size. That ratio yields an approximate number of value groups in the table. For a join based on the `<=>' comparison operator, `NULL' is not treated differently from any other value: `NULL <=> NULL', just as `N <=> N' for any other N. However, for a join based on the `=' operator, `NULL' is different from non-`NULL' values: `EXPR1 = EXPR2' is not true when EXPR1 or EXPR2 (or both) are `NULL'. This affects `ref' accesses for comparisons of the form `TBL_NAME.KEY = EXPR': MySQL will not access the table if the current value of EXPR is `NULL', because the comparison cannot be true. For `=' comparisons, it does not matter how many `NULL' values are in the table. For optimization purposes, the relevant value is the average size of the non-`NULL' value groups. However, MySQL does not currently enable that average size to be collected or used. For `MyISAM' tables, you have some control over collection of table statistics by means of the `myisam_stats_method' system variable. This variable has three possible values, which differ as follows: * When `myisam_stats_method' is `nulls_equal', all `NULL' values are treated as identical (that is, they all form a single value group). If the `NULL' value group size is much higher than the average non-`NULL' value group size, this method skews the average value group size upward. This makes index appear to the optimizer to be less useful than it really is for joins that look for non-`NULL' values. Consequently, the `nulls_equal' method may cause the optimizer not to use the index for `ref' accesses when it should. * When `myisam_stats_method' is `nulls_unequal', `NULL' values are not considered the same. Instead, each `NULL' value forms a separate value group of size 1. If you have many `NULL' values, this method skews the average value group size downward. If the average non-`NULL' value group size is large, counting `NULL' values each as a group of size 1 causes the optimizer to overestimate the value of the index for joins that look for non-`NULL' values. Consequently, the `nulls_unequal' method may cause the optimizer to use this index for `ref' lookups when other methods may be better. * When `myisam_stats_method' is `nulls_ignored', `NULL' values are ignored. If you tend to use many joins that use `<=>' rather than `=', `NULL' values are not special in comparisons and one `NULL' is equal to another. In this case, `nulls_equal' is the appropriate statistics method. The `myisam_stats_method' system variable has global and session values. Setting the global value affects `MyISAM' statistics collection for all `MyISAM' tables. Setting the session value affects statistics collection only for the current client connection. This means that you can force a table's statistics to be regenerated with a given method without affecting other clients by setting the session value of `myisam_stats_method'. To regenerate table statistics, you can use any of the following methods: * Execute *Note `myisamchk --stats_method=METHOD_NAME --analyze': myisamchk. * Change the table to cause its statistics to go out of date (for example, insert a row and then delete it), and then set `myisam_stats_method' and issue an *Note `ANALYZE TABLE': analyze-table. statement Some caveats regarding the use of `myisam_stats_method': * You can force table statistics to be collected explicitly, as just described. However, MySQL may also collect statistics automatically. For example, if during the course of executing statements for a table, some of those statements modify the table, MySQL may collect statistics. (This may occur for bulk inserts or deletes, or some *Note `ALTER TABLE': alter-table. statements, for example.) If this happens, the statistics are collected using whatever value `myisam_stats_method' has at the time. Thus, if you collect statistics using one method, but `myisam_stats_method' is set to the other method when a table's statistics are collected automatically later, the other method will be used. * There is no way to tell which method was used to generate statistics for a given `MyISAM' table. * `myisam_stats_method' applies only to `MyISAM' tables. Other storage engines have only one method for collecting table statistics. Usually it is closer to the `nulls_equal' method.  File: manual.info, Node: buffering-caching, Next: locking-issues, Prev: optimization-indexes, Up: optimization 8.6 Buffering and Caching ========================= * Menu: * myisam-key-cache:: The `MyISAM' Key Cache * innodb-buffer-pool:: The `InnoDB' Buffer Pool * query-cache:: The MySQL Query Cache MySQL uses several strategies that cache information in memory buffers to increase performance.  File: manual.info, Node: myisam-key-cache, Next: innodb-buffer-pool, Prev: buffering-caching, Up: buffering-caching 8.6.1 The `MyISAM' Key Cache ---------------------------- * Menu: * shared-key-cache:: Shared Key Cache Access * multiple-key-caches:: Multiple Key Caches * midpoint-insertion:: Midpoint Insertion Strategy * index-preloading:: Index Preloading * key-cache-block-size:: Key Cache Block Size * key-cache-restructuring:: Restructuring a Key Cache To minimize disk I/O, the `MyISAM' storage engine exploits a strategy that is used by many database management systems. It employs a cache mechanism to keep the most frequently accessed table blocks in memory: * For index blocks, a special structure called the _key cache_ (or _key buffer_) is maintained. The structure contains a number of block buffers where the most-used index blocks are placed. * For data blocks, MySQL uses no special cache. Instead it relies on the native operating system file system cache. This section first describes the basic operation of the `MyISAM' key cache. Then it discusses features that improve key cache performance and that enable you to better control cache operation: * Multiple sessions can access the cache concurrently. * You can set up multiple key caches and assign table indexes to specific caches. To control the size of the key cache, use the `key_buffer_size' system variable. If this variable is set equal to zero, no key cache is used. The key cache also is not used if the `key_buffer_size' value is too small to allocate the minimal number of block buffers (8). When the key cache is not operational, index files are accessed using only the native file system buffering provided by the operating system. (In other words, table index blocks are accessed using the same strategy as that employed for table data blocks.) An index block is a contiguous unit of access to the `MyISAM' index files. Usually the size of an index block is equal to the size of nodes of the index B-tree. (Indexes are represented on disk using a B-tree data structure. Nodes at the bottom of the tree are leaf nodes. Nodes above the leaf nodes are nonleaf nodes.) All block buffers in a key cache structure are the same size. This size can be equal to, greater than, or less than the size of a table index block. Usually one these two values is a multiple of the other. When data from any table index block must be accessed, the server first checks whether it is available in some block buffer of the key cache. If it is, the server accesses data in the key cache rather than on disk. That is, it reads from the cache or writes into it rather than reading from or writing to disk. Otherwise, the server chooses a cache block buffer containing a different table index block (or blocks) and replaces the data there by a copy of required table index block. As soon as the new index block is in the cache, the index data can be accessed. If it happens that a block selected for replacement has been modified, the block is considered `dirty.' In this case, prior to being replaced, its contents are flushed to the table index from which it came. Usually the server follows an _LRU (Least Recently Used)_ strategy: When choosing a block for replacement, it selects the least recently used index block. To make this choice easier, the key cache module maintains all used blocks in a special list (_LRU chain_) ordered by time of use. When a block is accessed, it is the most recently used and is placed at the end of the list. When blocks need to be replaced, blocks at the beginning of the list are the least recently used and become the first candidates for eviction. The `InnoDB' storage engine also uses an LRU algorithm, to manage its buffer pool. See *Note innodb-buffer-pool::.  File: manual.info, Node: shared-key-cache, Next: multiple-key-caches, Prev: myisam-key-cache, Up: myisam-key-cache 8.6.1.1 Shared Key Cache Access ............................... Threads can access key cache buffers simultaneously, subject to the following conditions: * A buffer that is not being updated can be accessed by multiple sessions. * A buffer that is being updated causes sessions that need to use it to wait until the update is complete. * Multiple sessions can initiate requests that result in cache block replacements, as long as they do not interfere with each other (that is, as long as they need different index blocks, and thus cause different cache blocks to be replaced). Shared access to the key cache enables the server to improve throughput significantly.  File: manual.info, Node: multiple-key-caches, Next: midpoint-insertion, Prev: shared-key-cache, Up: myisam-key-cache 8.6.1.2 Multiple Key Caches ........................... Shared access to the key cache improves performance but does not eliminate contention among sessions entirely. They still compete for control structures that manage access to the key cache buffers. To reduce key cache access contention further, MySQL also provides multiple key caches. This feature enables you to assign different table indexes to different key caches. Where there are multiple key caches, the server must know which cache to use when processing queries for a given `MyISAM' table. By default, all `MyISAM' table indexes are cached in the default key cache. To assign table indexes to a specific key cache, use the *Note `CACHE INDEX': cache-index. statement (see *Note cache-index::). For example, the following statement assigns indexes from the tables `t1', `t2', and `t3' to the key cache named `hot_cache': mysql> CACHE INDEX t1, t2, t3 IN hot_cache; +---------+--------------------+----------+----------+ | Table | Op | Msg_type | Msg_text | +---------+--------------------+----------+----------+ | test.t1 | assign_to_keycache | status | OK | | test.t2 | assign_to_keycache | status | OK | | test.t3 | assign_to_keycache | status | OK | +---------+--------------------+----------+----------+ The key cache referred to in a *Note `CACHE INDEX': cache-index. statement can be created by setting its size with a *Note `SET GLOBAL': set-option. parameter setting statement or by using server startup options. For example: mysql> SET GLOBAL keycache1.key_buffer_size=128*1024; To destroy a key cache, set its size to zero: mysql> SET GLOBAL keycache1.key_buffer_size=0; Note that you cannot destroy the default key cache. Any attempt to do this will be ignored: mysql> SET GLOBAL key_buffer_size = 0; mysql> SHOW VARIABLES LIKE 'key_buffer_size'; +-----------------+---------+ | Variable_name | Value | +-----------------+---------+ | key_buffer_size | 8384512 | +-----------------+---------+ Key cache variables are structured system variables that have a name and components. For `keycache1.key_buffer_size', `keycache1' is the cache variable name and `key_buffer_size' is the cache component. See *Note structured-system-variables::, for a description of the syntax used for referring to structured key cache system variables. By default, table indexes are assigned to the main (default) key cache created at the server startup. When a key cache is destroyed, all indexes assigned to it are reassigned to the default key cache. For a busy server, you can use a strategy that involves three key caches: * A `hot' key cache that takes up 20% of the space allocated for all key caches. Use this for tables that are heavily used for searches but that are not updated. * A `cold' key cache that takes up 20% of the space allocated for all key caches. Use this cache for medium-sized, intensively modified tables, such as temporary tables. * A `warm' key cache that takes up 60% of the key cache space. Employ this as the default key cache, to be used by default for all other tables. One reason the use of three key caches is beneficial is that access to one key cache structure does not block access to the others. Statements that access tables assigned to one cache do not compete with statements that access tables assigned to another cache. Performance gains occur for other reasons as well: * The hot cache is used only for retrieval queries, so its contents are never modified. Consequently, whenever an index block needs to be pulled in from disk, the contents of the cache block chosen for replacement need not be flushed first. * For an index assigned to the hot cache, if there are no queries requiring an index scan, there is a high probability that the index blocks corresponding to nonleaf nodes of the index B-tree remain in the cache. * An update operation most frequently executed for temporary tables is performed much faster when the updated node is in the cache and need not be read in from disk first. If the size of the indexes of the temporary tables are comparable with the size of cold key cache, the probability is very high that the updated node is in the cache. The *Note `CACHE INDEX': cache-index. statement sets up an association between a table and a key cache, but the association is lost each time the server restarts. If you want the association to take effect each time the server starts, one way to accomplish this is to use an option file: Include variable settings that configure your key caches, and an `init-file' option that names a file containing *Note `CACHE INDEX': cache-index. statements to be executed. For example: key_buffer_size = 4G hot_cache.key_buffer_size = 2G cold_cache.key_buffer_size = 2G init_file=/PATH/TO/DATA-DIRECTORY/mysqld_init.sql The statements in `mysqld_init.sql' are executed each time the server starts. The file should contain one SQL statement per line. The following example assigns several tables each to `hot_cache' and `cold_cache': CACHE INDEX db1.t1, db1.t2, db2.t3 IN hot_cache CACHE INDEX db1.t4, db2.t5, db2.t6 IN cold_cache  File: manual.info, Node: midpoint-insertion, Next: index-preloading, Prev: multiple-key-caches, Up: myisam-key-cache 8.6.1.3 Midpoint Insertion Strategy ................................... By default, the key cache management system uses a simple LRU strategy for choosing key cache blocks to be evicted, but it also supports a more sophisticated method called the _midpoint insertion strategy._ When using the midpoint insertion strategy, the LRU chain is divided into two parts: a hot sublist and a warm sublist. The division point between two parts is not fixed, but the key cache management system takes care that the warm part is not `too short,' always containing at least `key_cache_division_limit' percent of the key cache blocks. `key_cache_division_limit' is a component of structured key cache variables, so its value is a parameter that can be set per cache. When an index block is read from a table into the key cache, it is placed at the end of the warm sublist. After a certain number of hits (accesses of the block), it is promoted to the hot sublist. At present, the number of hits required to promote a block (3) is the same for all index blocks. A block promoted into the hot sublist is placed at the end of the list. The block then circulates within this sublist. If the block stays at the beginning of the sublist for a long enough time, it is demoted to the warm sublist. This time is determined by the value of the `key_cache_age_threshold' component of the key cache. The threshold value prescribes that, for a key cache containing N blocks, the block at the beginning of the hot sublist not accessed within the last `N * key_cache_age_threshold / 100' hits is to be moved to the beginning of the warm sublist. It then becomes the first candidate for eviction, because blocks for replacement always are taken from the beginning of the warm sublist. The midpoint insertion strategy enables you to keep more-valued blocks always in the cache. If you prefer to use the plain LRU strategy, leave the `key_cache_division_limit' value set to its default of 100. The midpoint insertion strategy helps to improve performance when execution of a query that requires an index scan effectively pushes out of the cache all the index blocks corresponding to valuable high-level B-tree nodes. To avoid this, you must use a midpoint insertion strategy with the `key_cache_division_limit' set to much less than 100. Then valuable frequently hit nodes are preserved in the hot sublist during an index scan operation as well.  File: manual.info, Node: index-preloading, Next: key-cache-block-size, Prev: midpoint-insertion, Up: myisam-key-cache 8.6.1.4 Index Preloading ........................ If there are enough blocks in a key cache to hold blocks of an entire index, or at least the blocks corresponding to its nonleaf nodes, it makes sense to preload the key cache with index blocks before starting to use it. Preloading enables you to put the table index blocks into a key cache buffer in the most efficient way: by reading the index blocks from disk sequentially. Without preloading, the blocks are still placed into the key cache as needed by queries. Although the blocks will stay in the cache, because there are enough buffers for all of them, they are fetched from disk in random order, and not sequentially. To preload an index into a cache, use the *Note `LOAD INDEX INTO CACHE': load-index. statement. For example, the following statement preloads nodes (index blocks) of indexes of the tables `t1' and `t2': mysql> LOAD INDEX INTO CACHE t1, t2 IGNORE LEAVES; +---------+--------------+----------+----------+ | Table | Op | Msg_type | Msg_text | +---------+--------------+----------+----------+ | test.t1 | preload_keys | status | OK | | test.t2 | preload_keys | status | OK | +---------+--------------+----------+----------+ The `IGNORE LEAVES' modifier causes only blocks for the nonleaf nodes of the index to be preloaded. Thus, the statement shown preloads all index blocks from `t1', but only blocks for the nonleaf nodes from `t2'. If an index has been assigned to a key cache using a *Note `CACHE INDEX': cache-index. statement, preloading places index blocks into that cache. Otherwise, the index is loaded into the default key cache.  File: manual.info, Node: key-cache-block-size, Next: key-cache-restructuring, Prev: index-preloading, Up: myisam-key-cache 8.6.1.5 Key Cache Block Size ............................ It is possible to specify the size of the block buffers for an individual key cache using the `key_cache_block_size' variable. This permits tuning of the performance of I/O operations for index files. The best performance for I/O operations is achieved when the size of read buffers is equal to the size of the native operating system I/O buffers. But setting the size of key nodes equal to the size of the I/O buffer does not always ensure the best overall performance. When reading the big leaf nodes, the server pulls in a lot of unnecessary data, effectively preventing reading other leaf nodes. To control the size of blocks in the `.MYI' index file of `MyISAM' tables, use the `--myisam-block-size' option at server startup.  File: manual.info, Node: key-cache-restructuring, Prev: key-cache-block-size, Up: myisam-key-cache 8.6.1.6 Restructuring a Key Cache ................................. A key cache can be restructured at any time by updating its parameter values. For example: mysql> SET GLOBAL cold_cache.key_buffer_size=4*1024*1024; If you assign to either the `key_buffer_size' or `key_cache_block_size' key cache component a value that differs from the component's current value, the server destroys the cache's old structure and creates a new one based on the new values. If the cache contains any dirty blocks, the server saves them to disk before destroying and re-creating the cache. Restructuring does not occur if you change other key cache parameters. When restructuring a key cache, the server first flushes the contents of any dirty buffers to disk. After that, the cache contents become unavailable. However, restructuring does not block queries that need to use indexes assigned to the cache. Instead, the server directly accesses the table indexes using native file system caching. File system caching is not as efficient as using a key cache, so although queries execute, a slowdown can be anticipated. After the cache has been restructured, it becomes available again for caching indexes assigned to it, and the use of file system caching for the indexes ceases.  File: manual.info, Node: innodb-buffer-pool, Next: query-cache, Prev: myisam-key-cache, Up: buffering-caching 8.6.2 The `InnoDB' Buffer Pool ------------------------------ *Note `InnoDB': innodb-storage-engine. maintains a buffer pool for caching data and indexes in memory. *Note `InnoDB': innodb-storage-engine. manages the pool as a list, using a least recently used (LRU) algorithm incorporating a midpoint insertion strategy. When room is needed to add a new block to the pool, *Note `InnoDB': innodb-storage-engine. evicts the least recently used block and adds the new block to the middle of the list. The midpoint insertion strategy in effect causes the list to be treated as two sublists: * At the head, a sublist of `new' (or `young') blocks that have been recently used. * At the tail, a sublist of `old' blocks that are less recently used. As a result of the algorithm, the new sublist contains blocks that are heavily used by queries. The old sublist contains less-used blocks, and candidates for eviction are taken from this sublist. The LRU algorithm operates as follows by default: * 3/8 of the buffer pool is devoted to the old sublist. * The midpoint of the list is the boundary where the tail of the new sublist meets the head of the old sublist. * When *Note `InnoDB': innodb-storage-engine. reads a block into the buffer pool, it initially inserts it at the midpoint (the head of the old sublist). A block can be read in as a result of two types of read requests: Because it is required (for example, to satisfy query execution), or as part of read-ahead performed in anticipation that it will be required. * The first access to a block in the old sublist makes it `young', causing it to move to the head of the buffer pool (the head of the new sublist). If the block was read in because it was required, the first access occurs immediately and the block is made young. If the block was read in due to read-ahead, the first access does not occur immediately (and might not occur at all before the block is evicted). * As long as no accesses occur for a block in the pool, it `ages' by moving toward the tail of the list. Blocks in both the new and old sublists age as other blocks are made new. Blocks in the old sublist also age as blocks are inserted at the midpoint. Eventually, a block that remains unused for long enough reaches the tail of the old sublist and is evicted. In the default operation of the buffer pool, a block when read in is loaded at the midpoint and then moved immediately to the head of the new sublist as soon as an access occurs. In the case of a table scan (such as performed for a *Note `mysqldump': mysqldump. operation), each block read by the scan ends up moving to the head of the new sublist because multiple rows are accessed from each block. This occurs even for a one-time scan, where the blocks are not otherwise used by other queries. Blocks may also be loaded by the read-ahead background thread and then moved to the head of the new sublist by a single access. These effects can be disadvantageous because they push blocks that are in heavy use by other queries out of the new sublist to the old sublist where they become subject to eviction. *Note `InnoDB': innodb-storage-engine. has several system variables that control the size of the buffer pool or enable LRU algorithm tuning: * `innodb_buffer_pool_size' Specifies the size of the buffer pool. If your buffer pool is small and you have sufficient memory, making the pool larger can improve performance by reducing the amount of disk I/O needed as queries access *Note `InnoDB': innodb-storage-engine. tables. * `innodb_old_blocks_pct' Specifies the approximate percentage of the buffer pool that *Note `InnoDB': innodb-storage-engine. uses for the old block sublist. The range of values is 5 to 95. The default value is 37 (that is, 3/8 of the pool). * `innodb_old_blocks_time' Specifies how long in milliseconds (ms) a block inserted into the old sublist must stay there after its first access before it can be moved to the new sublist. The default value is 0: A block inserted into the old sublist moves immediately to the new sublist the first time it is accessed, no matter how soon after insertion the access occurs. If the value is greater than 0, blocks remain in the old sublist until an access occurs at least that many ms after the first access. For example, a value of 1000 causes blocks to stay in the old sublist for 1 second after the first access before they become eligible to move to the new sublist. `innodb_old_blocks_pct' and `innodb_old_blocks_time' are available as of MySQL 5.1.41, but only for `InnoDB Plugin', not the built-in version of *Note `InnoDB': innodb-storage-engine. By setting `innodb_old_blocks_time' greater than 0, you can prevent one-time table scans from flooding the new sublist with blocks used only for the scan. Rows in a block read in for a scan are accessed rapidly many times in succession, but the block is unused after that. If `innodb_old_blocks_time' is set to a value greater than the block scan time, the block is not moved to the new sublist during the table scan. Instead, it remains in the old sublist and ages to the tail of the list to be evicted quickly. This way, blocks used only for a one-time scan do not act to the detriment of heavily used blocks in the new sublist. `innodb_old_blocks_time' can be set at runtime, so you can change it temporarily while performing operations such as table scans and dumps to prevent them from flooding the new sublist: SET GLOBAL innodb_old_blocks_time = 1000; ... PERFORM QUERIES THAT SCAN TABLES ... SET GLOBAL innodb_old_blocks_time = 0; This strategy does not apply if your intent is to fill the buffer pool with a table's content. For example, you might perform a table or index scan at server startup or during benchmarking or testing specifically to `warm up' the buffer pool. In this case, leaving `innodb_old_blocks_time' set to 0 accomplishes the goal of loading the scanned blocks into the new sublist. The output from the InnoDB Standard Monitor contains several new fields in the `BUFFER POOL AND MEMORY' section that pertain to operation of the buffer pool LRU algorithm: * `Old database pages': The number of pages in the old sublist of the buffer pool. * `Pages made young, not young': The number of old pages that were moved to the head of the buffer pool (the new sublist), and the number of pages that have remained in the old sublist without being made new. * `youngs/s non-youngs/s': The number of accesses to old pages that have resulted in making them young or not. This metric differs from that of the previous item in two ways. First, it relates only to old pages. Second, it is based on number of accesses to pages and not the number of pages. (There can be multiple accesses to a given page, all of which are counted.) * `young-making rate': Hits that cause blocks to move to the head of the buffer pool. * `not': Hits that do not cause blocks to move to the head of the buffer pool (due to the delay not being met). The `young-making' rate and `not' rate will not normally add up to the overall buffer pool hit rate. Hits for blocks in the old sublist cause them to move to the new sublist, but hits to blocks in the new sublist cause them to move to the head of the list only if they are a certain distance from the head. The preceding information from the Monitor can help you make LRU tuning decisions: * If you see very low `youngs/s' values when you do not have large scans going on, that indicates that you might need to either reduce the delay time, or increase the percentage of the buffer pool used for the old sublist. Increasing the percentage makes the old sublist larger, so blocks in that sublist take longer to move to the tail and be evicted. This increases the likelihood that they will be accessed again and be made young. * If you do not see a lot of `non-youngs/s' when you are doing large table scans (and lots of `youngs/s'), you will want to tune your delay value to be larger. For more information about InnoDB Monitors, see *Note innodb-monitors::. The `MyISAM' storage engine also uses an LRU algorithm, to manage its key cache. See *Note myisam-key-cache::.  File: manual.info, Node: query-cache, Prev: innodb-buffer-pool, Up: buffering-caching 8.6.3 The MySQL Query Cache --------------------------- * Menu: * query-cache-operation:: How the Query Cache Operates * query-cache-in-select:: Query Cache `SELECT' Options * query-cache-configuration:: Query Cache Configuration * query-cache-status-and-maintenance:: Query Cache Status and Maintenance The query cache stores the text of a *Note `SELECT': select. statement together with the corresponding result that was sent to the client. If an identical statement is received later, the server retrieves the results from the query cache rather than parsing and executing the statement again. The query cache is shared among sessions, so a result set generated by one client can be sent in response to the same query issued by another client. The query cache can be useful in an environment where you have tables that do not change very often and for which the server receives many identical queries. This is a typical situation for many Web servers that generate many dynamic pages based on database content. The query cache does not return stale data. When tables are modified, any relevant entries in the query cache are flushed. *Note*: The query cache does not work in an environment where you have multiple *Note `mysqld': mysqld. servers updating the same `MyISAM' tables. *Note*: As of MySQL 5.1.17, the query cache is used for prepared statements under the conditions described in *Note query-cache-operation::. Before 5.1.17, the query cache is not used for prepared statements. Some performance data for the query cache follows. These results were generated by running the MySQL benchmark suite on a Linux Alpha 2x500MHz system with 2GB RAM and a 64MB query cache. * If all the queries you are performing are simple (such as selecting a row from a table with one row), but still differ so that the queries cannot be cached, the overhead for having the query cache active is 13%. This could be regarded as the worst case scenario. In real life, queries tend to be much more complicated, so the overhead normally is significantly lower. * Searches for a single row in a single-row table are 238% faster with the query cache than without it. This can be regarded as close to the minimum speedup to be expected for a query that is cached. To disable the query cache at server startup, set the `query_cache_size' system variable to 0. By disabling the query cache code, there is no noticeable overhead. If you build MySQL from source, query cache capabilities can be excluded from the server entirely by invoking `configure' with the `--without-query-cache' option. The query cache offers the potential for substantial performance improvement, but you should not assume that it will do so under all circumstances. With some query cache configurations or server workloads, you might actually see a performance decrease: * Be cautious about sizing the query cache excessively large, which increases the overhead required to maintain the cache, possibly beyond the benefit of enabling it. Sizes in tens of megabytes are usually beneficial. Sizes in the hundreds of megabytes might not be. * Server workload has a significant effect on query cache efficiency. A query mix consisting almost entirely of a fixed set of *Note `SELECT': select. statements is much more likely to benefit from enabling the cache than a mix in which frequent *Note `INSERT': insert. statements cause continual invalidation of results in the cache. In some cases, a workaround is to use the `SQL_NO_CACHE' option to prevent results from even entering the cache for *Note `SELECT': select. statements that use frequently modified tables. (See *Note query-cache-in-select::.) To verify that enabling the query cache is beneficial, test the operation of your MySQL server with the cache enabled and disabled. Then retest periodically because query cache efficiency may change as server workload changes.  File: manual.info, Node: query-cache-operation, Next: query-cache-in-select, Prev: query-cache, Up: query-cache 8.6.3.1 How the Query Cache Operates .................................... This section describes how the query cache works when it is operational. *Note query-cache-configuration::, describes how to control whether it is operational. Incoming queries are compared to those in the query cache before parsing, so the following two queries are regarded as different by the query cache: SELECT * FROM TBL_NAME Select * from TBL_NAME Queries must be _exactly_ the same (byte for byte) to be seen as identical. In addition, query strings that are identical may be treated as different for other reasons. Queries that use different databases, different protocol versions, or different default character sets are considered different queries and are cached separately. The cache is not used for queries of the following types: * Queries that are a subquery of an outer query * Queries executed within the body of a stored function, trigger, or event Before a query result is fetched from the query cache, MySQL checks whether the user has *Note `SELECT': select. privilege for all databases and tables involved. If this is not the case, the cached result is not used. If a query result is returned from query cache, the server increments the `Qcache_hits' status variable, not `Com_select'. See *Note query-cache-status-and-maintenance::. If a table changes, all cached queries that use the table become invalid and are removed from the cache. This includes queries that use `MERGE' tables that map to the changed table. A table can be changed by many types of statements, such as *Note `INSERT': insert, *Note `UPDATE': update, *Note `DELETE': delete, *Note `TRUNCATE TABLE': truncate-table, *Note `ALTER TABLE': alter-table, *Note `DROP TABLE': drop-table, or *Note `DROP DATABASE': drop-database. The query cache also works within transactions when using `InnoDB' tables. In MySQL 5.1, the result from a *Note `SELECT': select. query on a view is cached. The query cache works for `SELECT SQL_CALC_FOUND_ROWS ...' queries and stores a value that is returned by a following `SELECT FOUND_ROWS()' query. `FOUND_ROWS()' returns the correct value even if the preceding query was fetched from the cache because the number of found rows is also stored in the cache. The `SELECT FOUND_ROWS()' query itself cannot be cached. Before MySQL 5.1.17, prepared statements do not use the query cache. Beginning with 5.1.17, prepared statements use the query cache under certain conditions, which differ depending on the preparation method: * Statements that are issued using the binary protocol using *Note `mysql_stmt_prepare()': mysql-stmt-prepare. and *Note `mysql_stmt_execute()': mysql-stmt-execute. See *Note c-api-prepared-statements::. For a prepared statement executed using the binary protocol, comparison with statements in the query cache is based on the text of the statement after expansion of `?' parameter markers. The statement is compared only with other cached statements that were executed using the binary protocol. That is, for query cache purposes, statements issued using the binary protocol are distinct from statements issued using the text protocol. * Statements that are issued using the text (nonbinary) protocol using *Note `PREPARE': prepare. and *Note `EXECUTE': execute. See *Note sql-syntax-prepared-statements::. These are denoted SQL PS statements here. Before MySQL 5.1.21, for a prepared statement executed using *Note `PREPARE': prepare. and *Note `EXECUTE': execute, it is not cached if it contains any `?' parameter markers. In that case, the statement after parameter expansion contains references to user variables, which prevents caching, even for nonprepared statements. If the statement contains no parameter markers, the statement is compared with statements in the query cache that were executed using the text protocol (that is, it is compared with other SQL PS statements and nonprepared statements). As of MySQL 5.1.21, this limitation is lifted and prepared statements that contain parameter markers can be cached because expansion directly substitutes the user variable values. A query cannot be cached if it contains any of the functions shown in the following table. `BENCHMARK()' `CONNECTION_ID()' `CONVERT_TZ()' `CURDATE()' `CURRENT_DATE()' `CURRENT_TIME()' `CURRENT_TIMESTAMP()' `CURTIME()' `DATABASE()' `ENCRYPT()' with one `FOUND_ROWS()' `GET_LOCK()' parameter `LAST_INSERT_ID()' `LOAD_FILE()' `MASTER_POS_WAIT()' `NOW()' `RAND()' `RELEASE_LOCK()' `SLEEP()' `SYSDATE()' `UNIX_TIMESTAMP()' with no parameters `USER()' `UUID()' `UUID_SHORT()' A query also is not cached under these conditions: * It refers to user-defined functions (UDFs) or stored functions. * It refers to user variables or local stored program variables. * It refers to tables in the `mysql' or `INFORMATION_SCHEMA' system database. * It is of any of the following forms: SELECT ... LOCK IN SHARE MODE SELECT ... FOR UPDATE SELECT ... INTO OUTFILE ... SELECT ... INTO DUMPFILE ... SELECT * FROM ... WHERE autoincrement_col IS NULL The last form is not cached because it is used as the ODBC workaround for obtaining the last insert ID value. See the MyODBC section of *Note connectors-apis::. Statements within transactions that use `SERIALIZABLE' isolation level also cannot be cached because they use `LOCK IN SHARE MODE' locking. * It uses `TEMPORARY' tables. * It does not use any tables. * It generates warnings. * The user has a column-level privilege for any of the involved tables.  File: manual.info, Node: query-cache-in-select, Next: query-cache-configuration, Prev: query-cache-operation, Up: query-cache 8.6.3.2 Query Cache `SELECT' Options .................................... Two query cache-related options may be specified in *Note `SELECT': select. statements: * `SQL_CACHE' The query result is cached if it is cacheable and the value of the `query_cache_type' system variable is `ON' or `DEMAND'. * `SQL_NO_CACHE' The query result is not cached. Examples: SELECT SQL_CACHE id, name FROM customer; SELECT SQL_NO_CACHE id, name FROM customer;  File: manual.info, Node: query-cache-configuration, Next: query-cache-status-and-maintenance, Prev: query-cache-in-select, Up: query-cache 8.6.3.3 Query Cache Configuration ................................. The `have_query_cache' server system variable indicates whether the query cache is available: mysql> SHOW VARIABLES LIKE 'have_query_cache'; +------------------+-------+ | Variable_name | Value | +------------------+-------+ | have_query_cache | YES | +------------------+-------+ When using a standard MySQL binary, this value is always `YES', even if query caching is disabled. Several other system variables control query cache operation. These can be set in an option file or on the command line when starting *Note `mysqld': mysqld. The query cache system variables all have names that begin with `query_cache_'. They are described briefly in *Note server-system-variables::, with additional configuration information given here. To set the size of the query cache, set the `query_cache_size' system variable. Setting it to 0 disables the query cache. The default size is 0, so the query cache is disabled by default. *Note*: When using the Windows Configuration Wizard to install or configure MySQL, the default value for `query_cache_size' will be configured automatically for you based on the different configuration types available. When using the Windows Configuration Wizard, the query cache may be enabled (that is, set to a nonzero value) due to the selected configuration. The query cache is also controlled by the setting of the `query_cache_type' variable. You should check the values of these variables as set in your `my.ini' file after configuration has taken place. When you set `query_cache_size' to a nonzero value, keep in mind that the query cache needs a minimum size of about 40KB to allocate its structures. (The exact size depends on system architecture.) If you set the value too small, you'll get a warning, as in this example: mysql> SET GLOBAL query_cache_size = 40000; Query OK, 0 rows affected, 1 warning (0.00 sec) mysql> SHOW WARNINGS\G *************************** 1. row *************************** Level: Warning Code: 1282 Message: Query cache failed to set size 39936; new query cache size is 0 mysql> SET GLOBAL query_cache_size = 41984; Query OK, 0 rows affected (0.00 sec) mysql> SHOW VARIABLES LIKE 'query_cache_size'; +------------------+-------+ | Variable_name | Value | +------------------+-------+ | query_cache_size | 41984 | +------------------+-------+ For the query cache to actually be able to hold any query results, its size must be set larger: mysql> SET GLOBAL query_cache_size = 1000000; Query OK, 0 rows affected (0.04 sec) mysql> SHOW VARIABLES LIKE 'query_cache_size'; +------------------+--------+ | Variable_name | Value | +------------------+--------+ | query_cache_size | 999424 | +------------------+--------+ 1 row in set (0.00 sec) The `query_cache_size' value is aligned to the nearest 1024 byte block. The value reported may therefore be different from the value that you assign. If the query cache size is greater than 0, the `query_cache_type' variable influences how it works. This variable can be set to the following values: * A value of `0' or `OFF' prevents caching or retrieval of cached results. * A value of `1' or `ON' enables caching except of those statements that begin with `SELECT SQL_NO_CACHE'. * A value of `2' or `DEMAND' causes caching of only those statements that begin with `SELECT SQL_CACHE'. Setting the `GLOBAL' `query_cache_type' value determines query cache behavior for all clients that connect after the change is made. Individual clients can control cache behavior for their own connection by setting the `SESSION' `query_cache_type' value. For example, a client can disable use of the query cache for its own queries like this: mysql> SET SESSION query_cache_type = OFF; If you set `query_cache_type' at server startup (rather than at runtime with a *Note `SET': set-option. statement), only the numeric values are permitted. To control the maximum size of individual query results that can be cached, set the `query_cache_limit' system variable. The default value is 1MB. *Note*: You can set the maximum size that can be specified for the query cache at run time with the *Note `SET': set-option. statement by using the `--maximum-query_cache_size=32M' option on the command line or in the configuration file. When a query is to be cached, its result (the data sent to the client) is stored in the query cache during result retrieval. Therefore the data usually is not handled in one big chunk. The query cache allocates blocks for storing this data on demand, so when one block is filled, a new block is allocated. Because memory allocation operation is costly (timewise), the query cache allocates blocks with a minimum size given by the `query_cache_min_res_unit' system variable. When a query is executed, the last result block is trimmed to the actual data size so that unused memory is freed. Depending on the types of queries your server executes, you might find it helpful to tune the value of `query_cache_min_res_unit': * The default value of `query_cache_min_res_unit' is 4KB. This should be adequate for most cases. * If you have a lot of queries with small results, the default block size may lead to memory fragmentation, as indicated by a large number of free blocks. Fragmentation can force the query cache to prune (delete) queries from the cache due to lack of memory. In this case, you should decrease the value of `query_cache_min_res_unit'. The number of free blocks and queries removed due to pruning are given by the values of the `Qcache_free_blocks' and `Qcache_lowmem_prunes' status variables. * If most of your queries have large results (check the `Qcache_total_blocks' and `Qcache_queries_in_cache' status variables), you can increase performance by increasing `query_cache_min_res_unit'. However, be careful to not make it too large (see the previous item).  File: manual.info, Node: query-cache-status-and-maintenance, Prev: query-cache-configuration, Up: query-cache 8.6.3.4 Query Cache Status and Maintenance .......................................... To check whether the query cache is present in your MySQL server, use the following statement: mysql> SHOW VARIABLES LIKE 'have_query_cache'; +------------------+-------+ | Variable_name | Value | +------------------+-------+ | have_query_cache | YES | +------------------+-------+ You can defragment the query cache to better utilize its memory with the *Note `FLUSH QUERY CACHE': flush. statement. The statement does not remove any queries from the cache. The `RESET QUERY CACHE' statement removes all query results from the query cache. The *Note `FLUSH TABLES': flush. statement also does this. To monitor query cache performance, use *Note `SHOW STATUS': show-status. to view the cache status variables: mysql> SHOW STATUS LIKE 'Qcache%'; +-------------------------+--------+ | Variable_name | Value | +-------------------------+--------+ | Qcache_free_blocks | 36 | | Qcache_free_memory | 138488 | | Qcache_hits | 79570 | | Qcache_inserts | 27087 | | Qcache_lowmem_prunes | 3114 | | Qcache_not_cached | 22989 | | Qcache_queries_in_cache | 415 | | Qcache_total_blocks | 912 | +-------------------------+--------+ Descriptions of each of these variables are given in *Note server-status-variables::. Some uses for them are described here. The total number of *Note `SELECT': select. queries is given by this formula: Com_select + Qcache_hits + queries with errors found by parser The `Com_select' value is given by this formula: Qcache_inserts + Qcache_not_cached + queries with errors found during the column-privileges check The query cache uses variable-length blocks, so `Qcache_total_blocks' and `Qcache_free_blocks' may indicate query cache memory fragmentation. After *Note `FLUSH QUERY CACHE': flush, only a single free block remains. Every cached query requires a minimum of two blocks (one for the query text and one or more for the query results). Also, every table that is used by a query requires one block. However, if two or more queries use the same table, only one table block needs to be allocated. The information provided by the `Qcache_lowmem_prunes' status variable can help you tune the query cache size. It counts the number of queries that have been removed from the cache to free up memory for caching new queries. The query cache uses a least recently used (LRU) strategy to decide which queries to remove from the cache. Tuning information is given in *Note query-cache-configuration::.  File: manual.info, Node: locking-issues, Next: optimizing-database-structure, Prev: buffering-caching, Up: optimization 8.7 Locking Issues ================== * Menu: * internal-locking:: Internal Locking Methods * table-locking:: Table Locking Issues * concurrent-inserts:: Concurrent Inserts * external-locking:: External Locking MySQL manages contention for table contents using locking: * Internal locking is performed within the MySQL server itself to manage contention for table contents by multiple threads. This type of locking is internal because it is performed entirely by the server and involves no other programs. See *Note internal-locking::. * External locking occurs when the server and other programs lock *Note `MyISAM': myisam-storage-engine. table files to coordinate among themselves which program can access the tables at which time. See *Note external-locking::.  File: manual.info, Node: internal-locking, Next: table-locking, Prev: locking-issues, Up: locking-issues 8.7.1 Internal Locking Methods ------------------------------ This section discusses internal locking; that is, locking performed within the MySQL server itself to manage contention for table contents by multiple sessions. This type of locking is internal because it is performed entirely by the server and involves no other programs. External locking occurs when the server and other programs lock *Note `MyISAM': myisam-storage-engine. table files to coordinate among themselves which program can access the tables at which time. See *Note external-locking::. MySQL uses row-level locking for `InnoDB' tables, and table-level locking for `MyISAM', `MEMORY', and `MERGE' tables. Which lock type works better for your application depends on the application and its workload, especially whether the data is modified frequently and how many concurrent sessions need to read or write the same tables. Different parts of an application may require different lock types. To decide whether you want to use a storage engine with row-level locking, look at what your application does and what mix of select and update statements it uses. For example, the `InnoDB' storage engine is targeted towards a wide variety of application workloads, especially those with heavy write activity or high concurrent usage. The `MyISAM' storage engine is targeted towards Web applications that perform many selects, relatively few deletes, updates based mainly on key values, and inserts into a few specific tables. * Considerations for Table Locking * Table locking in MySQL is deadlock-free for storage engines that use table-level locking. Deadlock avoidance is managed by always requesting all needed locks at once at the beginning of a query and always locking the tables in the same order. MySQL grants table write locks as follows: 1. If there are no locks on the table, put a write lock on it. 2. Otherwise, put the lock request in the write lock queue. MySQL grants table read locks as follows: 1. If there are no write locks on the table, put a read lock on it. 2. Otherwise, put the lock request in the read lock queue. Table updates are given higher priority than table retrievals. Therefore, when a lock is released, the lock is made available to the requests in the write lock queue and then to the requests in the read lock queue. This ensures that updates to a table are not `starved' even if there is heavy *Note `SELECT': select. activity for the table. However, if you have many updates for a table, *Note `SELECT': select. statements wait until there are no more updates. For information on altering the priority of reads and writes, see *Note table-locking::. You can analyze the table lock contention on your system by checking the `Table_locks_immediate' and `Table_locks_waited' status variables, which indicate the number of times that requests for table locks could be granted immediately and the number that had to wait, respectively: mysql> SHOW STATUS LIKE 'Table%'; +-----------------------+---------+ | Variable_name | Value | +-----------------------+---------+ | Table_locks_immediate | 1151552 | | Table_locks_waited | 15324 | +-----------------------+---------+ The `MyISAM' storage engine supports concurrent inserts to reduce contention between readers and writers for a given table: If a `MyISAM' table has no free blocks in the middle of the data file, rows are always inserted at the end of the data file. In this case, you can freely mix concurrent *Note `INSERT': insert. and *Note `SELECT': select. statements for a `MyISAM' table without locks. That is, you can insert rows into a `MyISAM' table at the same time other clients are reading from it. Holes can result from rows having been deleted from or updated in the middle of the table. If there are holes, concurrent inserts are disabled but are enabled again automatically when all holes have been filled with new data. This behavior is altered by the `concurrent_insert' system variable. See *Note concurrent-inserts::. If you acquire a table lock explicitly with *Note `LOCK TABLES': lock-tables, you can request a `READ LOCAL' lock rather than a `READ' lock to enable other sessions to perform concurrent inserts while you have the table locked. To perform many *Note `INSERT': insert. and *Note `SELECT': select. operations on a table `real_table' when concurrent inserts are not possible, you can insert rows into a temporary table `temp_table' and update the real table with the rows from the temporary table periodically. This can be done with the following code: mysql> LOCK TABLES real_table WRITE, temp_table WRITE; mysql> INSERT INTO real_table SELECT * FROM temp_table; mysql> DELETE FROM temp_table; mysql> UNLOCK TABLES; `InnoDB' uses row locks. Deadlocks are possible for `InnoDB' because it automatically acquires locks during the processing of SQL statements, not at the start of the transaction. * Considerations for Row Locking * Advantages of row-level locking: * Fewer lock conflicts when different sessions access different rows * Fewer changes for rollbacks * Possible to lock a single row for a long time Disadvantages of row-level locking: * Requires more memory than table-level locks * Slower than table-level locks when used on a large part of the table because you must acquire many more locks * Slower than other locks if you often do `GROUP BY' operations on a large part of the data or if you must scan the entire table frequently * Choosing the Type of Locking * Generally, table locks are superior to row-level locks in the following cases: * Most statements for the table are reads * Statements for the table are a mix of reads and writes, where writes are updates or deletes for a single row that can be fetched with one key read: UPDATE TBL_NAME SET COLUMN=VALUE WHERE UNIQUE_KEY_COL=KEY_VALUE; DELETE FROM TBL_NAME WHERE UNIQUE_KEY_COL=KEY_VALUE; * *Note `SELECT': select. combined with concurrent *Note `INSERT': insert. statements, and very few *Note `UPDATE': update. or *Note `DELETE': delete. statements * Many scans or `GROUP BY' operations on the entire table without any writers With higher-level locks, you can more easily tune applications by supporting locks of different types, because the lock overhead is less than for row-level locks. Options other than row-level locking: * Versioning (such as that used in MySQL for concurrent inserts) where it is possible to have one writer at the same time as many readers. This means that the database or table supports different views for the data depending on when access begins. Other common terms for this are `time travel,' `copy on write,' or `copy on demand.' * Copy on demand is in many cases superior to row-level locking. However, in the worst case, it can use much more memory than using normal locks. * Instead of using row-level locks, you can employ application-level locks, such as those provided by `GET_LOCK()' and `RELEASE_LOCK()' in MySQL. These are advisory locks, so they work only with applications that cooperate with each other. See *Note miscellaneous-functions::.  File: manual.info, Node: table-locking, Next: concurrent-inserts, Prev: internal-locking, Up: locking-issues 8.7.2 Table Locking Issues -------------------------- To achieve a very high lock speed, MySQL uses table locking (instead of page, row, or column locking) for all storage engines except `InnoDB' and *Note `NDBCLUSTER': mysql-cluster. For `InnoDB' tables, MySQL uses table locking only if you explicitly lock the table with *Note `LOCK TABLES': lock-tables. For this storage engine, avoid using *Note `LOCK TABLES': lock-tables. at all, because `InnoDB' uses automatic row-level locking to ensure transaction isolation. For large tables, table locking is often better than row locking, but there are some disadvantages: * Table locking enables many sessions to read from a table at the same time, but if a session wants to write to a table, it must first get exclusive access. During the update, all other sessions that want to access this particular table must wait until the update is done. * Table locking causes problems in cases such as when a session is waiting because the disk is full and free space needs to become available before the session can proceed. In this case, all sessions that want to access the problem table are also put in a waiting state until more disk space is made available. Table locking is also disadvantageous under the following scenario: * A session issues a *Note `SELECT': select. that takes a long time to run. * Another session then issues an *Note `UPDATE': update. on the same table. This session waits until the *Note `SELECT': select. is finished. * Another session issues another *Note `SELECT': select. statement on the same table. Because *Note `UPDATE': update. has higher priority than *Note `SELECT': select, this *Note `SELECT': select. waits for the *Note `UPDATE': update. to finish, _after_ waiting for the first *Note `SELECT': select. to finish. The following items describe some ways to avoid or reduce contention caused by table locking: * Try to get the *Note `SELECT': select. statements to run faster so that they lock tables for a shorter time. You might have to create some summary tables to do this. * Start *Note `mysqld': mysqld. with `--low-priority-updates'. For storage engines that use only table-level locking (such as `MyISAM', `MEMORY', and `MERGE'), this gives all statements that update (modify) a table lower priority than *Note `SELECT': select. statements. In this case, the second *Note `SELECT': select. statement in the preceding scenario would execute before the *Note `UPDATE': update. statement, and would not need to wait for the first *Note `SELECT': select. to finish. * To specify that all updates issued in a specific connection should be done with low priority, set the `low_priority_updates' server system variable equal to 1. * To give a specific *Note `INSERT': insert, *Note `UPDATE': update, or *Note `DELETE': delete. statement lower priority, use the `LOW_PRIORITY' attribute. * To give a specific *Note `SELECT': select. statement higher priority, use the `HIGH_PRIORITY' attribute. See *Note select::. * Start *Note `mysqld': mysqld. with a low value for the `max_write_lock_count' system variable to force MySQL to temporarily elevate the priority of all *Note `SELECT': select. statements that are waiting for a table after a specific number of inserts to the table occur. This permits `READ' locks after a certain number of `WRITE' locks. * If you have problems with *Note `INSERT': insert. combined with *Note `SELECT': select, consider switching to `MyISAM' tables, which support concurrent *Note `SELECT': select. and *Note `INSERT': insert. statements. (See *Note concurrent-inserts::.) * If you mix inserts and deletes on the same table, *Note `INSERT DELAYED': insert-delayed. may be of great help. See *Note insert-delayed::. * If you have problems with mixed *Note `SELECT': select. and *Note `DELETE': delete. statements, the `LIMIT' option to *Note `DELETE': delete. may help. See *Note delete::. * Using `SQL_BUFFER_RESULT' with *Note `SELECT': select. statements can help to make the duration of table locks shorter. See *Note select::. * You could change the locking code in `mysys/thr_lock.c' to use a single queue. In this case, write locks and read locks would have the same priority, which might help some applications. Here are some tips concerning table locks in MySQL: * Concurrent users are not a problem if you do not mix updates with selects that need to examine many rows in the same table. * You can use *Note `LOCK TABLES': lock-tables. to increase speed, because many updates within a single lock is much faster than updating without locks. Splitting table contents into separate tables may also help. * If you encounter speed problems with table locks in MySQL, you may be able to improve performance by converting some of your tables to `InnoDB'. See *Note innodb-storage-engine::.  File: manual.info, Node: concurrent-inserts, Next: external-locking, Prev: table-locking, Up: locking-issues 8.7.3 Concurrent Inserts ------------------------ The `MyISAM' storage engine supports concurrent inserts to reduce contention between readers and writers for a given table: If a `MyISAM' table has no holes in the data file (deleted rows in the middle), an *Note `INSERT': insert. statement can be executed to add rows to the end of the table at the same time that *Note `SELECT': select. statements are reading rows from the table. If there are multiple *Note `INSERT': insert. statements, they are queued and performed in sequence, concurrently with the *Note `SELECT': select. statements. The results of a concurrent *Note `INSERT': insert. may not be visible immediately. The `concurrent_insert' system variable can be set to modify the concurrent-insert processing. By default, the variable is set to 1 and concurrent inserts are handled as just described. If `concurrent_insert' is set to 0, concurrent inserts are disabled. If the variable is set to 2, concurrent inserts at the end of the table are permitted even for tables that have deleted rows. See also the description of the `concurrent_insert' system variable. Under circumstances where concurrent inserts can be used, there is seldom any need to use the `DELAYED' modifier for *Note `INSERT': insert. statements. See *Note insert-delayed::. If you are using the binary log, concurrent inserts are converted to normal inserts for `CREATE ... SELECT' or *Note `INSERT ... SELECT': insert-select. statements. This is done to ensure that you can re-create an exact copy of your tables by applying the log during a backup operation. See *Note binary-log::. In addition, for those statements a read lock is placed on the selected-from table such that inserts into that table are blocked. The effect is that concurrent inserts for that table must wait as well. With *Note `LOAD DATA INFILE': load-data, if you specify `CONCURRENT' with a `MyISAM' table that satisfies the condition for concurrent inserts (that is, it contains no free blocks in the middle), other sessions can retrieve data from the table while *Note `LOAD DATA': load-data. is executing. Use of the `CONCURRENT' option affects the performance of *Note `LOAD DATA': load-data. a bit, even if no other session is using the table at the same time. If you specify `HIGH_PRIORITY', it overrides the effect of the `--low-priority-updates' option if the server was started with that option. It also causes concurrent inserts not to be used. For *Note `LOCK TABLE': lock-tables, the difference between `READ LOCAL' and `READ' is that `READ LOCAL' permits nonconflicting *Note `INSERT': insert. statements (concurrent inserts) to execute while the lock is held. However, this cannot be used if you are going to manipulate the database using processes external to the server while you hold the lock.  File: manual.info, Node: external-locking, Prev: concurrent-inserts, Up: locking-issues 8.7.4 External Locking ---------------------- External locking is the use of file system locking to manage contention for *Note `MyISAM': myisam-storage-engine. database tables by multiple processes. External locking is used in situations where a single process such as the MySQL server cannot be assumed to be the only process that requires access to tables. Here are some examples: * If you run multiple servers that use the same database directory (not recommended), each server must have external locking enabled. * If you use *Note `myisamchk': myisamchk. to perform table maintenance operations on *Note `MyISAM': myisam-storage-engine. tables, you must either ensure that the server is not running, or that the server has external locking enabled so that it locks table files as necessary to coordinate with *Note `myisamchk': myisamchk. for access to the tables. The same is true for use of *Note `myisampack': myisampack. to pack *Note `MyISAM': myisam-storage-engine. tables. If the server is run with external locking enabled, you can use *Note `myisamchk': myisamchk. at any time for read operations such a checking tables. In this case, if the server tries to update a table that *Note `myisamchk': myisamchk. is using, the server will wait for *Note `myisamchk': myisamchk. to finish before it continues. If you use *Note `myisamchk': myisamchk. for write operations such as repairing or optimizing tables, or if you use *Note `myisampack': myisampack. to pack tables, you _must_ always ensure that the *Note `mysqld': mysqld. server is not using the table. If you don't stop *Note `mysqld': mysqld, you should at least do a *Note `mysqladmin flush-tables': mysqladmin. before you run *Note `myisamchk': myisamchk. Your tables _may become corrupted_ if the server and *Note `myisamchk': myisamchk. access the tables simultaneously. With external locking in effect, each process that requires access to a table acquires a file system lock for the table files before proceeding to access the table. If all necessary locks cannot be acquired, the process is blocked from accessing the table until the locks can be obtained (after the process that currently holds the locks releases them). External locking affects server performance because the server must sometimes wait for other processes before it can access tables. External locking is unnecessary if you run a single server to access a given data directory (which is the usual case) and if no other programs such as *Note `myisamchk': myisamchk. need to modify tables while the server is running. If you only _read_ tables with other programs, external locking is not required, although *Note `myisamchk': myisamchk. might report warnings if the server changes tables while *Note `myisamchk': myisamchk. is reading them. With external locking disabled, to use *Note `myisamchk': myisamchk, you must either stop the server while *Note `myisamchk': myisamchk. executes or else lock and flush the tables before running *Note `myisamchk': myisamchk. (See *Note system-optimization::.) To avoid this requirement, use the *Note `CHECK TABLE': check-table. and *Note `REPAIR TABLE': repair-table. statements to check and repair *Note `MyISAM': myisam-storage-engine. tables. For *Note `mysqld': mysqld, external locking is controlled by the value of the `skip_external_locking' system variable. When this variable is enabled, external locking is disabled, and vice versa. From MySQL 4.0 on, external locking is disabled by default. Use of external locking can be controlled at server startup by using the `--external-locking' or `--skip-external-locking' option. If you do use external locking option to enable updates to *Note `MyISAM': myisam-storage-engine. tables from many MySQL processes, you must ensure that the following conditions are satisfied: * You should not use the query cache for queries that use tables that are updated by another process. * You should not start the server with the `--delay-key-write=ALL' option or use the `DELAY_KEY_WRITE=1' table option for any shared tables. Otherwise, index corruption can occur. The easiest way to satisfy these conditions is to always use `--external-locking' together with `--delay-key-write=OFF' and `--query-cache-size=0'. (This is not done by default because in many setups it is useful to have a mixture of the preceding options.)  File: manual.info, Node: optimizing-database-structure, Next: optimizing-the-server, Prev: locking-issues, Up: optimization 8.8 Optimizing Database Structure ================================= * Menu: * data-size:: Make Your Data as Small as Possible * table-cache:: How MySQL Opens and Closes Tables * creating-many-tables:: Disadvantages of Creating Many Tables in the Same Database * internal-temporary-tables:: How MySQL Uses Internal Temporary Tables  File: manual.info, Node: data-size, Next: table-cache, Prev: optimizing-database-structure, Up: optimizing-database-structure 8.8.1 Make Your Data as Small as Possible ----------------------------------------- Design your tables to minimize their space on the disk. This can result in huge improvements by reducing the amount of data written to and read from disk. Smaller tables normally require less main memory while their contents are being actively processed during query execution. Any space reduction for table data also results in smaller indexes that can be processed faster. MySQL supports many different storage engines (table types) and row formats. For each table, you can decide which storage and indexing method to use. Choosing the proper table format for your application may give you a big performance gain. See *Note storage-engines::. You can get better performance for a table and minimize storage space by using the techniques listed here: * Use the most efficient (smallest) data types possible. MySQL has many specialized types that save disk space and memory. For example, use the smaller integer types if possible to get smaller tables. *Note `MEDIUMINT': numeric-types. is often a better choice than *Note `INT': numeric-types. because a *Note `MEDIUMINT': numeric-types. column uses 25% less space. * Declare columns to be `NOT NULL' if possible. It makes everything faster and you save one bit per column. If you really need `NULL' in your application, you should definitely use it. Just avoid having it on all columns by default. * For `MyISAM' tables, if you do not have any variable-length columns (*Note `VARCHAR': char, *Note `TEXT': blob, or *Note `BLOB': blob. columns), a fixed-size row format is used. This is faster but may waste some space. See *Note myisam-table-formats::. You can hint that you want to have fixed length rows even if you have *Note `VARCHAR': char. columns with the *Note `CREATE TABLE': create-table. option `ROW_FORMAT=FIXED'. * `InnoDB' tables use a compact storage format. In versions of MySQL earlier than 5.0.3, `InnoDB' rows contain some redundant information, such as the number of columns and the length of each column, even for fixed-size columns. By default, tables are created in the compact format (`ROW_FORMAT=COMPACT'). If you wish to downgrade to older versions of MySQL, you can request the old format with `ROW_FORMAT=REDUNDANT'. The presence of the compact row format decreases row storage space by about 20% at the cost of increasing CPU use for some operations. If your workload is a typical one that is limited by cache hit rates and disk speed it is likely to be faster. If it is a rare case that is limited by CPU speed, it might be slower. The compact `InnoDB' format also changes how *Note `CHAR': char. columns containing UTF-8 data are stored. With `ROW_FORMAT=REDUNDANT', a UTF-8 `CHAR(N)' occupies 3 x N bytes, given that the maximum length of a UTF-8 encoded character is three bytes. Many languages can be written primarily using single-byte UTF-8 characters, so a fixed storage length often wastes space. With `ROW_FORMAT=COMPACT' format, `InnoDB' allocates a variable amount of storage in the range from N to 3 x N bytes for these columns by stripping trailing spaces if necessary. The minimum storage length is kept as N bytes to facilitate in-place updates in typical cases. * The primary index of a table should be as short as possible. This makes identification of each row easy and efficient. * Create only the indexes that you really need. Indexes are good for retrieval but bad when you need to store data quickly. If you access a table mostly by searching on a combination of columns, create an index on them. The first part of the index should be the column most used. If you _always_ use many columns when selecting from the table, the first column in the index should be the one with the most duplicates to obtain better compression of the index. * If it is very likely that a string column has a unique prefix on the first number of characters, it is better to index only this prefix, using MySQL's support for creating an index on the leftmost part of the column (see *Note create-index::). Shorter indexes are faster, not only because they require less disk space, but because they also give you more hits in the index cache, and thus fewer disk seeks. See *Note server-parameters::. * In some circumstances, it can be beneficial to split into two a table that is scanned very often. This is especially true if it is a dynamic-format table and it is possible to use a smaller static format table that can be used to find the relevant rows when scanning the table.  File: manual.info, Node: table-cache, Next: creating-many-tables, Prev: data-size, Up: optimizing-database-structure 8.8.2 How MySQL Opens and Closes Tables --------------------------------------- When you execute a *Note `mysqladmin status': mysqladmin. command, you should see something like this: Uptime: 426 Running threads: 1 Questions: 11082 Reloads: 1 Open tables: 12 The `Open tables' value of 12 can be somewhat puzzling if you have only six tables. MySQL is multi-threaded, so there may be many clients issuing queries for a given table simultaneously. To minimize the problem with multiple client sessions having different states on the same table, the table is opened independently by each concurrent session. This uses additional memory but normally increases performance. With `MyISAM' tables, one extra file descriptor is required for the data file for each client that has the table open. (By contrast, the index file descriptor is shared between all sessions.) *Note*: `table_open_cache' was known as `table_cache' in MySQL 5.1.2 and earlier. The `table_open_cache' and `max_connections' system variables affect the maximum number of files the server keeps open. If you increase one or both of these values, you may run up against a limit imposed by your operating system on the per-process number of open file descriptors. Many operating systems permit you to increase the open-files limit, although the method varies widely from system to system. Consult your operating system documentation to determine whether it is possible to increase the limit and how to do so. `table_open_cache' is related to `max_connections'. For example, for 200 concurrent running connections, you should have a table cache size of at least `200 * N', where N is the maximum number of tables per join in any of the queries which you execute. You must also reserve some extra file descriptors for temporary tables and files. Make sure that your operating system can handle the number of open file descriptors implied by the `table_open_cache' setting. If `table_open_cache' is set too high, MySQL may run out of file descriptors and refuse connections, fail to perform queries, and be very unreliable. You also have to take into account that the `MyISAM' storage engine needs two file descriptors for each unique open table. You can increase the number of file descriptors available to MySQL using the `--open-files-limit' startup option to *Note `mysqld': mysqld. See *Note not-enough-file-handles::. The cache of open tables is kept at a level of `table_open_cache' entries. The default value is 64; this can be changed with the `--table_open_cache' option to *Note `mysqld': mysqld. Note that MySQL may temporarily open more tables than this to execute queries. MySQL closes an unused table and removes it from the table cache under the following circumstances: * When the cache is full and a thread tries to open a table that is not in the cache. * When the cache contains more than `table_open_cache' entries and a table in the cache is no longer being used by any threads. * When a table flushing operation occurs. This happens when someone issues a *Note `FLUSH TABLES': flush. statement or executes a *Note `mysqladmin flush-tables': mysqladmin. or *Note `mysqladmin refresh': mysqladmin. command. When the table cache fills up, the server uses the following procedure to locate a cache entry to use: * Tables that are not currently in use are released, beginning with the table least recently used. * If a new table needs to be opened, but the cache is full and no tables can be released, the cache is temporarily extended as necessary. When the cache is in a temporarily extended state and a table goes from a used to unused state, the table is closed and released from the cache. A `MyISAM' table is opened for each concurrent access. This means the table needs to be opened twice if two threads access the same table or if a thread accesses the table twice in the same query (for example, by joining the table to itself). Each concurrent open requires an entry in the table cache. The first open of any `MyISAM' table takes two file descriptors: one for the data file and one for the index file. Each additional use of the table takes only one file descriptor for the data file. The index file descriptor is shared among all threads. If you are opening a table with the `HANDLER TBL_NAME OPEN' statement, a dedicated table object is allocated for the thread. This table object is not shared by other threads and is not closed until the thread calls `HANDLER TBL_NAME CLOSE' or the thread terminates. When this happens, the table is put back in the table cache (if the cache is not full). See *Note handler::. You can determine whether your table cache is too small by checking the *Note `mysqld': mysqld. status variable `Opened_tables', which indicates the number of table-opening operations since the server started: mysql> SHOW GLOBAL STATUS LIKE 'Opened_tables'; +---------------+-------+ | Variable_name | Value | +---------------+-------+ | Opened_tables | 2741 | +---------------+-------+ If the value is very large or increases rapidly, even when you have not issued many *Note `FLUSH TABLES': flush. statements, you should increase the table cache size. See *Note server-system-variables::, and *Note server-status-variables::.  File: manual.info, Node: creating-many-tables, Next: internal-temporary-tables, Prev: table-cache, Up: optimizing-database-structure 8.8.3 Disadvantages of Creating Many Tables in the Same Database ---------------------------------------------------------------- If you have many `MyISAM' tables in the same database directory, open, close, and create operations are slow. If you execute *Note `SELECT': select. statements on many different tables, there is a little overhead when the table cache is full, because for every table that has to be opened, another must be closed. You can reduce this overhead by increasing the number of entries permitted in the table cache.  File: manual.info, Node: internal-temporary-tables, Prev: creating-many-tables, Up: optimizing-database-structure 8.8.4 How MySQL Uses Internal Temporary Tables ---------------------------------------------- In some cases, the server creates internal temporary tables while processing queries. Such a table can be held in memory and processed by the `MEMORY' storage engine, or stored on disk and processed by the `MyISAM' storage engine. The server may create a temporary table initially as an in-memory table, then convert it to an on-disk table if it becomes too large. Users have no direct control over when the server creates an internal temporary table or which storage engine the server uses to manage it. Temporary tables can be created under conditions such as these: * If there is an `ORDER BY' clause and a different `GROUP BY' clause, or if the `ORDER BY' or `GROUP BY' contains columns from tables other than the first table in the join queue, a temporary table is created. * `DISTINCT' combined with `ORDER BY' may require a temporary table. * If you use the `SQL_SMALL_RESULT' option, MySQL uses an in-memory temporary table, unless the query also contains elements (described later) that require on-disk storage. To determine whether a query requires a temporary table, use *Note `EXPLAIN': explain. and check the `Extra' column to see whether it says `Using temporary'. See *Note using-explain::. Some conditions prevent the use of an in-memory temporary table, in which case the server uses an on-disk table instead: * Presence of a *Note `BLOB': blob. or *Note `TEXT': blob. column in the table * Presence of any column in a `GROUP BY' or `DISTINCT' clause larger than 512 bytes * Presence of any column larger than 512 bytes in the *Note `SELECT': select. list, if *Note `UNION': union. or *Note `UNION ALL': union. is used The *Note `SHOW COLUMNS': show-columns. and The *Note `DESCRIBE': describe. statements use `BLOB' as the type for some columns, thus the temporary table used for the results is an on-disk table. If an internal temporary table is created initially as an in-memory table but becomes too large, MySQL automatically converts it to an on-disk table. The maximum size for in-memory temporary tables is the minimum of the `tmp_table_size' and `max_heap_table_size' values. This differs from `MEMORY' tables explicitly created with *Note `CREATE TABLE': create-table.: For such tables, the `max_heap_table_size' system variable determines how large the table is permitted to grow and there is no conversion to on-disk format. When the server creates an internal temporary table (either in memory or on disk), it increments the `Created_tmp_tables' status variable. If the server creates the table on disk (either initially or by converting an in-memory table) it increments the `Created_tmp_disk_tables' status variable.  File: manual.info, Node: optimizing-the-server, Next: thread-information, Prev: optimizing-database-structure, Up: optimization 8.9 Optimizing the MySQL Server =============================== * Menu: * system-optimization:: System Factors and Startup Parameter Tuning * server-parameters:: Tuning Server Parameters * connection-threads:: How MySQL Uses Threads for Client Connections * memory-use:: How MySQL Uses Memory * disk-issues:: Disk Issues * symbolic-links:: Using Symbolic Links * large-page-support:: Enabling Large Page Support * dns:: How MySQL Uses DNS  File: manual.info, Node: system-optimization, Next: server-parameters, Prev: optimizing-the-server, Up: optimizing-the-server 8.9.1 System Factors and Startup Parameter Tuning ------------------------------------------------- We start with system-level factors, because some of these decisions must be made very early to achieve large performance gains. In other cases, a quick look at this section may suffice. However, it is always nice to have a sense of how much can be gained by changing factors that apply at this level. The operating system to use is very important. To get the best use of multiple-CPU machines, you should use Solaris (because its threads implementation works well) or Linux (because the 2.4 and later kernels have good SMP support). Note that older Linux kernels have a 2GB filesize limit by default. If you have such a kernel and a need for files larger than 2GB, you should get the Large File Support (LFS) patch for the ext2 file system. Other file systems such as ReiserFS and XFS do not have this 2GB limitation. Before using MySQL in production, we advise you to test it on your intended platform. Other tips: * If you have enough RAM, you could remove all swap devices. Some operating systems use a swap device in some contexts even if you have free memory. * Avoid external locking for *Note `MyISAM': myisam-storage-engine. tables. Since MySQL 4.0, the default has been for external locking to be disabled on all systems. The `--external-locking' and `--skip-external-locking' options explicitly enable and disable external locking. Note that disabling external locking does not affect MySQL's functionality as long as you run only one server. Just remember to take down the server (or lock and flush the relevant tables) before you run *Note `myisamchk': myisamchk. On some systems it is mandatory to disable external locking because it does not work, anyway. The only case in which you cannot disable external locking is when you run multiple MySQL _servers_ (not clients) on the same data, or if you run *Note `myisamchk': myisamchk. to check (not repair) a table without telling the server to flush and lock the tables first. Note that using multiple MySQL servers to access the same data concurrently is generally _not_ recommended, except when using MySQL Cluster. The *Note `LOCK TABLES': lock-tables. and *Note `UNLOCK TABLES': lock-tables. statements use internal locking, so you can use them even if external locking is disabled.  File: manual.info, Node: server-parameters, Next: connection-threads, Prev: system-optimization, Up: optimizing-the-server 8.9.2 Tuning Server Parameters ------------------------------ You can determine the default buffer sizes used by the *Note `mysqld': mysqld. server using this command: shell> mysqld --verbose --help This command produces a list of all *Note `mysqld': mysqld. options and configurable system variables. The output includes the default variable values and looks something like this: abort-slave-event-count 0 allow-suspicious-udfs FALSE auto-increment-increment 1 auto-increment-offset 1 automatic-sp-privileges TRUE back_log 50 basedir /home/jon/bin/mysql-5.1/ bind-address (No default value) binlog-row-event-max-size 1024 binlog_cache_size 32768 binlog_format (No default value) bulk_insert_buffer_size 8388608 character-set-client-handshake TRUE character-set-filesystem binary character-set-server latin1 character-sets-dir /home/jon/bin/mysql-5.1/share/mysql/charsets/ chroot (No default value) collation-server latin1_swedish_ci completion-type 0 concurrent-insert 1 connect_timeout 10 console FALSE datadir . datetime_format %Y-%m-%d %H:%i:%s date_format %Y-%m-%d default-character-set latin1 default-collation latin1_swedish_ci default-storage-engine MyISAM default-table-type MyISAM default-time-zone (No default value) default_week_format 0 delayed_insert_limit 100 delayed_insert_timeout 300 delayed_queue_size 1000 disconnect-slave-event-count 0 div_precision_increment 4 enable-locking FALSE engine-condition-pushdown TRUE expire_logs_days 0 external-locking FALSE flush_time 0 ft_max_word_len 84 ft_min_word_len 4 ft_query_expansion_limit 20 ft_stopword_file (No default value) gdb FALSE general_log FALSE general_log_file (No default value) group_concat_max_len 1024 help TRUE init-connect (No default value) init-file (No default value) init-slave (No default value) innodb TRUE innodb-adaptive-hash-index TRUE innodb-additional-mem-pool-size 1048576 innodb-autoextend-increment 8 innodb-autoinc-lock-mode 1 innodb-buffer-pool-size 8388608 innodb-checksums TRUE innodb-commit-concurrency 0 innodb-concurrency-tickets 500 innodb-data-file-path (No default value) innodb-data-home-dir (No default value) innodb-doublewrite TRUE innodb-fast-shutdown 1 innodb-file-io-threads 4 innodb-file-per-table FALSE innodb-flush-log-at-trx-commit 1 innodb-flush-method (No default value) innodb-force-recovery 0 innodb-lock-wait-timeout 50 innodb-locks-unsafe-for-binlog FALSE innodb-log-buffer-size 1048576 innodb-log-file-size 5242880 innodb-log-files-in-group 2 innodb-log-group-home-dir (No default value) innodb-max-dirty-pages-pct 90 innodb-max-purge-lag 0 innodb-mirrored-log-groups 1 innodb-open-files 300 innodb-rollback-on-timeout FALSE innodb-stats-on-metadata TRUE innodb-status-file FALSE innodb-support-xa TRUE innodb-sync-spin-loops 20 innodb-table-locks TRUE innodb-thread-concurrency 8 innodb-thread-sleep-delay 10000 interactive_timeout 28800 join_buffer_size 131072 keep_files_on_create FALSE key_buffer_size 8384512 key_cache_age_threshold 300 key_cache_block_size 1024 key_cache_division_limit 100 language /home/jon/bin/mysql-5.1/share/mysql/english/ large-pages FALSE lc-time-names en_US local-infile TRUE log (No default value) log-bin (No default value) log-bin-index (No default value) log-bin-trust-function-creators FALSE log-bin-trust-routine-creators FALSE log-error log-isam myisam.log log-output FILE log-queries-not-using-indexes FALSE log-short-format FALSE log-slave-updates FALSE log-slow-admin-statements FALSE log-slow-slave-statements FALSE log-tc tc.log log-tc-size 24576 log-update (No default value) log-warnings 1 log_slow_queries (No default value) long_query_time 10 low-priority-updates FALSE lower_case_table_names 0 master-connect-retry 60 master-host (No default value) master-info-file master.info master-password (No default value) master-port 3306 master-retry-count 86400 master-ssl FALSE master-ssl-ca (No default value) master-ssl-capath (No default value) master-ssl-cert (No default value) master-ssl-cipher (No default value) master-ssl-key (No default value) master-user test max-binlog-dump-events 0 max_allowed_packet 1048576 max_binlog_cache_size 18446744073709547520 max_binlog_size 1073741824 max_connections 151 max_connect_errors 10 max_delayed_threads 20 max_error_count 64 max_heap_table_size 16777216 max_join_size 18446744073709551615 max_length_for_sort_data 1024 max_prepared_stmt_count 16382 max_relay_log_size 0 max_seeks_for_key 18446744073709551615 max_sort_length 1024 max_sp_recursion_depth 0 max_tmp_tables 32 max_user_connections 0 max_write_lock_count 18446744073709551615 memlock FALSE min_examined_row_limit 0 multi_range_count 256 myisam-recover OFF myisam_block_size 1024 myisam_data_pointer_size 6 myisam_max_extra_sort_file_size 2147483648 myisam_max_sort_file_size 9223372036853727232 myisam_repair_threads 1 myisam_sort_buffer_size 8388608 myisam_stats_method nulls_unequal myisam_use_mmap FALSE ndb-autoincrement-prefetch-sz 1 ndb-cache-check-time 0 ndb-connectstring (No default value) ndb-extra-logging 0 ndb-force-send TRUE ndb-index-stat-enable FALSE ndb-mgmd-host (No default value) ndb-nodeid 0 ndb-optimized-node-selection TRUE ndb-report-thresh-binlog-epoch-slip 3 ndb-report-thresh-binlog-mem-usage 10 ndb-shm FALSE ndb-use-copying-alter-table FALSE ndb-use-exact-count TRUE ndb-use-transactions TRUE ndb_force_send TRUE ndb_use_exact_count TRUE ndb_use_transactions TRUE net_buffer_length 16384 net_read_timeout 30 net_retry_count 10 net_write_timeout 60 new FALSE old FALSE old-alter-table FALSE old-passwords FALSE old-style-user-limits FALSE open_files_limit 1024 optimizer_prune_level 1 optimizer_search_depth 62 pid-file /home/jon/bin/mysql-5.1/var/tonfisk.pid plugin-load (No default value) plugin_dir /home/jon/bin/mysql-5.1/lib/mysql/plugin port 3306 port-open-timeout 0 preload_buffer_size 32768 profiling_history_size 15 query_alloc_block_size 8192 query_cache_limit 1048576 query_cache_min_res_unit 4096 query_cache_size 0 query_cache_type 1 query_cache_wlock_invalidate FALSE query_prealloc_size 8192 range_alloc_block_size 4096 read_buffer_size 131072 read_only FALSE read_rnd_buffer_size 262144 record_buffer 131072 relay-log (No default value) relay-log-index (No default value) relay-log-info-file relay-log.info relay_log_purge TRUE relay_log_space_limit 0 replicate-same-server-id FALSE report-host (No default value) report-password (No default value) report-port 3306 report-user (No default value) rpl-recovery-rank 0 safe-user-create FALSE secure-auth FALSE secure-file-priv (No default value) server-id 0 show-slave-auth-info FALSE skip-grant-tables FALSE skip-slave-start FALSE slave-exec-mode STRICT slave-load-tmpdir /tmp slave_compressed_protocol FALSE slave_net_timeout 3600 slave_transaction_retries 10 slow-query-log FALSE slow_launch_time 2 slow_query_log_file (No default value) socket /tmp/mysql.sock sort_buffer_size 2097144 sporadic-binlog-dump-fail FALSE sql-mode OFF symbolic-links TRUE sync-binlog 0 sync-frm TRUE sysdate-is-now FALSE table_definition_cache 256 table_lock_wait_timeout 50 table_open_cache 64 tc-heuristic-recover (No default value) temp-pool TRUE thread_cache_size 0 thread_concurrency 10 thread_stack 262144 timed_mutexes FALSE time_format %H:%i:%s tmpdir (No default value) tmp_table_size 16777216 transaction_alloc_block_size 8192 transaction_prealloc_size 4096 updatable_views_with_limit 1 use-symbolic-links TRUE verbose TRUE wait_timeout 28800 warnings 1 For a *Note `mysqld': mysqld. server that is currently running, you can see the current values of its system variables by connecting to it and issuing this statement: mysql> SHOW VARIABLES; You can also see some statistical and status indicators for a running server by issuing this statement: mysql> SHOW STATUS; System variable and status information also can be obtained using *Note `mysqladmin': mysqladmin.: shell> mysqladmin variables shell> mysqladmin extended-status For a full description of all system and status variables, see *Note server-system-variables::, and *Note server-status-variables::. MySQL uses algorithms that are very scalable, so you can usually run with very little memory. However, normally you get better performance by giving MySQL more memory. When tuning a MySQL server, the two most important variables to configure are `key_buffer_size' and `table_open_cache'. You should first feel confident that you have these set appropriately before trying to change any other variables. The following examples indicate some typical variable values for different runtime configurations. * If you have at least 256MB of memory and many tables and want maximum performance with a moderate number of clients, you should use something like this: shell> mysqld_safe --key_buffer_size=64M --table_open_cache=256 \ --sort_buffer_size=4M --read_buffer_size=1M & * If you have only 128MB of memory and only a few tables, but you still do a lot of sorting, you can use something like this: shell> mysqld_safe --key_buffer_size=16M --sort_buffer_size=1M If there are very many simultaneous connections, swapping problems may occur unless *Note `mysqld': mysqld. has been configured to use very little memory for each connection. *Note `mysqld': mysqld. performs better if you have enough memory for all connections. * With little memory and lots of connections, use something like this: shell> mysqld_safe --key_buffer_size=512K --sort_buffer_size=100K \ --read_buffer_size=100K & Or even this: shell> mysqld_safe --key_buffer_size=512K --sort_buffer_size=16K \ --table_open_cache=32 --read_buffer_size=8K \ --net_buffer_length=1K & If you are performing `GROUP BY' or `ORDER BY' operations on tables that are much larger than your available memory, you should increase the value of `read_rnd_buffer_size' to speed up the reading of rows following sorting operations. You can make use of the example option files included with your MySQL distribution; see *Note option-files-preconfigured::. If you specify an option on the command line for *Note `mysqld': mysqld. or *Note `mysqld_safe': mysqld-safe, it remains in effect only for that invocation of the server. To use the option every time the server runs, put it in an option file. To see the effects of a parameter change, do something like this: shell> mysqld --key_buffer_size=32M --verbose --help The variable values are listed near the end of the output. Make sure that the `--verbose' and `--help' options are last. Otherwise, the effect of any options listed after them on the command line are not reflected in the output. For information on tuning the `InnoDB' storage engine, see *Note innodb-tuning::.  File: manual.info, Node: connection-threads, Next: memory-use, Prev: server-parameters, Up: optimizing-the-server 8.9.3 How MySQL Uses Threads for Client Connections --------------------------------------------------- Connection manager threads handle client connection requests on the network interfaces that the server listens to. On all platforms, one manager thread handles TCP/IP connection requests. On Unix, this manager thread also handles Unix socket file connection requests. On Windows, a manager thread handles shared-memory connection requests, and another handles named-pipe connection requests. The server does not create threads to handle interfaces that it does not listen to. For example, a Windows server that does not have support for named-pipe connections enabled does not create a thread to handle them. Connection manager threads associate each client connection with a thread dedicated to it that handles authentication and request processing for that connection. Manager threads create a new thread when necessary but try to avoid doing so by consulting the thread cache first to see whether it contains a thread that can be used for the connection. When a connection ends, its thread is returned to the thread cache if the cache is not full. In this connection thread model, there are as many threads as there are clients currently connected, which has some disadvantages when server workload must scale to handle large numbers of connections. For example, thread creation and disposal becomes expensive. Also, each thread requires server and kernel resources, such as stack space. To accommodate a large number of simultaneous connections, the stack size per thread must be kept small, leading to a situation where it is either too small or the server consumes large amounts of memory. Exhaustion of other resources can occur as well, and scheduling overhead can become significant. To control and monitor how the server manages threads that handle client connections, several system and status variables are relevant. (See *Note server-system-variables::, and *Note server-status-variables::.) The thread cache has a size determined by the `thread_cache_size' system variable. The default value is 0 (no caching), which causes a thread to be set up for each new connection and disposed of when the connection terminates. Set `thread_cache_size' to N to enable N inactive connection threads to be cached. `thread_cache_size' can be set at server startup or changed while the server runs. A connection thread becomes inactive when the client connection with which it was associated terminates. To monitor the number of threads in the cache and how many threads have been created because a thread could not be taken from the cache, monitor the `Threads_cached' and `Threads_created' status variables. You can set `max_connections' at server startup or at runtime to control the maximum number of clients that can connect simultaneously. When the thread stack is too small, this limits the complexity of the SQL statements which the server can handle, the recursion depth of stored procedures, and other memory-consuming actions. To set a stack size of N bytes for each thread, start the server with `--thread_stack=N'.  File: manual.info, Node: memory-use, Next: disk-issues, Prev: connection-threads, Up: optimizing-the-server 8.9.4 How MySQL Uses Memory --------------------------- The following list indicates some of the ways that the *Note `mysqld': mysqld. server uses memory. Where applicable, the name of the system variable relevant to the memory use is given: * All threads share the *Note `MyISAM': myisam-storage-engine. key buffer; its size is determined by the `key_buffer_size' variable. Other buffers used by the server are allocated as needed. See *Note server-parameters::. * Each thread that is used to manage client connections uses some thread-specific space. The following list indicates these and which variables control their size: * A stack (variable `thread_stack') * A connection buffer (variable `net_buffer_length') * A result buffer (variable `net_buffer_length') The connection buffer and result buffer each begin with a size equal to `net_buffer_length' bytes, but are dynamically enlarged up to `max_allowed_packet' bytes as needed. The result buffer shrinks to `net_buffer_length' bytes after each SQL statement. While a statement is running, a copy of the current statement string is also allocated. * All threads share the same base memory. * When a thread is no longer needed, the memory allocated to it is released and returned to the system unless the thread goes back into the thread cache. In that case, the memory remains allocated. * Before MySQL 5.1.4, only compressed `MyISAM' tables are memory mapped. As of MySQL 5.1.4, the `myisam_use_mmap' system variable can be set to 1 to enable memory-mapping for all `MyISAM' tables. * Each request that performs a sequential scan of a table allocates a _read buffer_ (variable `read_buffer_size'). * When reading rows in an arbitrary sequence (for example, following a sort), a _random-read buffer_ (variable `read_rnd_buffer_size') may be allocated to avoid disk seeks. * All joins are executed in a single pass, and most joins can be done without even using a temporary table. Most temporary tables are memory-based hash tables. Temporary tables with a large row length (calculated as the sum of all column lengths) or that contain *Note `BLOB': blob. columns are stored on disk. If an internal in-memory temporary table becomes too large, MySQL handles this automatically by changing the table from in-memory to on-disk format, to be handled by the `MyISAM' storage engine. You can increase the permissible temporary table size as described in *Note internal-temporary-tables::. * Most requests that perform a sort allocate a sort buffer and zero to two temporary files depending on the result set size. See *Note temporary-files::. * Almost all parsing and calculating is done in thread-local and reusable memory pools. No memory overhead is needed for small items, so the normal slow memory allocation and freeing is avoided. Memory is allocated only for unexpectedly large strings. * For each `MyISAM' table that is opened, the index file is opened once; the data file is opened once for each concurrently running thread. For each concurrent thread, a table structure, column structures for each column, and a buffer of size `3 * N' are allocated (where N is the maximum row length, not counting *Note `BLOB': blob. columns). A *Note `BLOB': blob. column requires five to eight bytes plus the length of the *Note `BLOB': blob. data. The `MyISAM' storage engine maintains one extra row buffer for internal use. * For each table having *Note `BLOB': blob. columns, a buffer is enlarged dynamically to read in larger *Note `BLOB': blob. values. If you scan a table, a buffer as large as the largest *Note `BLOB': blob. value is allocated. * Handler structures for all in-use tables are saved in a cache and managed as a FIFO. The initial cache size is taken from the value of the `table_open_cache' system variable. If a table has been used by two running threads at the same time, the cache contains two entries for the table. See *Note table-cache::. * A *Note `FLUSH TABLES': flush. statement or *Note `mysqladmin flush-tables': mysqladmin. command closes all tables that are not in use at once and marks all in-use tables to be closed when the currently executing thread finishes. This effectively frees most in-use memory. *Note `FLUSH TABLES': flush. does not return until all tables have been closed. * The server caches information in memory as a result of *Note `GRANT': grant, *Note `CREATE USER': create-user, *Note `CREATE SERVER': create-server, and *Note `INSTALL PLUGIN': install-plugin. statements. This memory is not released by the corresponding *Note `REVOKE': revoke, *Note `DROP USER': drop-user, *Note `DROP SERVER': drop-server, and *Note `UNINSTALL PLUGIN': uninstall-plugin. statements, so for a server that executes many instances of the statements that cause caching, there will be an increase in memory use. This cached memory can be freed with *Note `FLUSH PRIVILEGES': flush. `ps' and other system status programs may report that *Note `mysqld': mysqld. uses a lot of memory. This may be caused by thread stacks on different memory addresses. For example, the Solaris version of `ps' counts the unused memory between stacks as used memory. To verify this, check available swap with `swap -s'. We test *Note `mysqld': mysqld. with several memory-leakage detectors (both commercial and Open Source), so there should be no memory leaks.  File: manual.info, Node: disk-issues, Next: symbolic-links, Prev: memory-use, Up: optimizing-the-server 8.9.5 Disk Issues ----------------- * Disk seeks are a huge performance bottleneck. This problem becomes more apparent when the amount of data starts to grow so large that effective caching becomes impossible. For large databases where you access data more or less randomly, you can be sure that you need at least one disk seek to read and a couple of disk seeks to write things. To minimize this problem, use disks with low seek times. * Increase the number of available disk spindles (and thereby reduce the seek overhead) by either symlinking files to different disks or striping the disks: * Using symbolic links This means that, for `MyISAM' tables, you symlink the index file and data files from their usual location in the data directory to another disk (that may also be striped). This makes both the seek and read times better, assuming that the disk is not used for other purposes as well. See *Note symbolic-links::. * Striping Striping means that you have many disks and put the first block on the first disk, the second block on the second disk, and the N-th block on the (`N MOD NUMBER_OF_DISKS') disk, and so on. This means if your normal data size is less than the stripe size (or perfectly aligned), you get much better performance. Striping is very dependent on the operating system and the stripe size, so benchmark your application with different stripe sizes. See *Note custom-benchmarks::. The speed difference for striping is _very_ dependent on the parameters. Depending on how you set the striping parameters and number of disks, you may get differences measured in orders of magnitude. You have to choose to optimize for random or sequential access. * For reliability, you may want to use RAID 0+1 (striping plus mirroring), but in this case, you need 2 x N drives to hold N drives of data. This is probably the best option if you have the money for it. However, you may also have to invest in some volume-management software to handle it efficiently. * A good option is to vary the RAID level according to how critical a type of data is. For example, store semi-important data that can be regenerated on a RAID 0 disk, but store really important data such as host information and logs on a RAID 0+1 or RAID N disk. RAID N can be a problem if you have many writes, due to the time required to update the parity bits. * On Linux, you can get much better performance by using `hdparm' to configure your disk's interface. (Up to 100% under load is not uncommon.) The following `hdparm' options should be quite good for MySQL, and probably for many other applications: hdparm -m 16 -d 1 Note that performance and reliability when using this command depend on your hardware, so we strongly suggest that you test your system thoroughly after using `hdparm'. Please consult the `hdparm' manual page for more information. If `hdparm' is not used wisely, file system corruption may result, so back up everything before experimenting! * You can also set the parameters for the file system that the database uses: If you do not need to know when files were last accessed (which is not really useful on a database server), you can mount your file systems with the `-o noatime' option. That skips updates to the last access time in inodes on the file system, which avoids some disk seeks. On many operating systems, you can set a file system to be updated asynchronously by mounting it with the `-o async' option. If your computer is reasonably stable, this should give you better performance without sacrificing too much reliability. (This flag is on by default on Linux.)  File: manual.info, Node: symbolic-links, Next: large-page-support, Prev: disk-issues, Up: optimizing-the-server 8.9.6 Using Symbolic Links -------------------------- * Menu: * symbolic-links-to-databases:: Using Symbolic Links for Databases on Unix * symbolic-links-to-tables:: Using Symbolic Links for Tables on Unix * windows-symbolic-links:: Using Symbolic Links for Databases on Windows You can move tables and databases from the database directory to other locations and replace them with symbolic links to the new locations. You might want to do this, for example, to move a database to a file system with more free space or increase the speed of your system by spreading your tables to different disk. The recommended way to do this is simply to symlink databases to a different disk. Symlink tables only as a last resort.  File: manual.info, Node: symbolic-links-to-databases, Next: symbolic-links-to-tables, Prev: symbolic-links, Up: symbolic-links 8.9.6.1 Using Symbolic Links for Databases on Unix .................................................. On Unix, the way to symlink a database is first to create a directory on some disk where you have free space and then to create a symlink to it from the MySQL data directory. shell> mkdir /dr1/databases/test shell> ln -s /dr1/databases/test /PATH/TO/DATADIR MySQL does not support linking one directory to multiple databases. Replacing a database directory with a symbolic link works as long as you do not make a symbolic link between databases. Suppose that you have a database `db1' under the MySQL data directory, and then make a symlink `db2' that points to `db1': shell> cd /PATH/TO/DATADIR shell> ln -s db1 db2 The result is that, or any table `tbl_a' in `db1', there also appears to be a table `tbl_a' in `db2'. If one client updates `db1.tbl_a' and another client updates `db2.tbl_a', problems are likely to occur. However, if you really need to do this, it is possible by altering the source file `mysys/my_symlink.c', in which you should look for the following statement: if (!(MyFlags & MY_RESOLVE_LINK) || (!lstat(filename,&stat_buff) && S_ISLNK(stat_buff.st_mode))) Change the statement to this: if (1)  File: manual.info, Node: symbolic-links-to-tables, Next: windows-symbolic-links, Prev: symbolic-links-to-databases, Up: symbolic-links 8.9.6.2 Using Symbolic Links for Tables on Unix ............................................... You should not symlink tables on systems that do not have a fully operational `realpath()' call. (Linux and Solaris support `realpath()'). You can check whether your system supports symbolic links by issuing a `SHOW VARIABLES LIKE 'have_symlink'' statement. Symlinks are fully supported only for `MyISAM' tables. For files used by tables for other storage engines, you may get strange problems if you try to use symbolic links. The handling of symbolic links for `MyISAM' tables works as follows: * In the data directory, you always have the table format (`.frm') file, the data (`.MYD') file, and the index (`.MYI') file. The data file and index file can be moved elsewhere and replaced in the data directory by symlinks. The format file cannot. * You can symlink the data file and the index file independently to different directories. * You can instruct a running MySQL server to perform the symlinking by using the `DATA DIRECTORY' and `INDEX DIRECTORY' options to *Note `CREATE TABLE': create-table. See *Note create-table::. Alternatively, symlinking can be accomplished manually from the command line using `ln -s' if *Note `mysqld': mysqld. is not running. *Note*: Beginning with MySQL 5.1.24, the path used with either or both of the `DATA DIRECTORY' and `INDEX DIRECTORY' options may not include the MySQL `data' directory. (Bug#32167) * *Note `myisamchk': myisamchk. does not replace a symlink with the data file or index file. It works directly on the file to which the symlink points. Any temporary files are created in the directory where the data file or index file is located. The same is true for the *Note `ALTER TABLE': alter-table, *Note `OPTIMIZE TABLE': optimize-table, and *Note `REPAIR TABLE': repair-table. statements. * *Note*: When you drop a table that is using symlinks, _both the symlink and the file to which the symlink points are dropped_. This is an extremely good reason why you should _not_ run *Note `mysqld': mysqld. as the system `root' or permit system users to have write access to MySQL database directories. * If you rename a table with `ALTER TABLE ... RENAME' or *Note `RENAME TABLE': rename-table. and you do not move the table to another database, the symlinks in the database directory are renamed to the new names and the data file and index file are renamed accordingly. * If you use `ALTER TABLE ... RENAME' or *Note `RENAME TABLE': rename-table. to move a table to another database, the table is moved to the other database directory. If the table name changed, the symlinks in the new database directory are renamed to the new names and the data file and index file are renamed accordingly. * If you are not using symlinks, you should use the `--skip-symbolic-links' option to *Note `mysqld': mysqld. to ensure that no one can use *Note `mysqld': mysqld. to drop or rename a file outside of the data directory. Table symlink operations that are not yet supported: * *Note `ALTER TABLE': alter-table. ignores the `DATA DIRECTORY' and `INDEX DIRECTORY' table options. * *Note `BACKUP TABLE': backup-table. and *Note `RESTORE TABLE': restore-table. do not respect symbolic links. * The `.frm' file must _never_ be a symbolic link (as indicated previously, only the data and index files can be symbolic links). Attempting to do this (for example, to make synonyms) produces incorrect results. Suppose that you have a database `db1' under the MySQL data directory, a table `tbl1' in this database, and in the `db1' directory you make a symlink `tbl2' that points to `tbl1': shell> cd /PATH/TO/DATADIR/db1 shell> ln -s tbl1.frm tbl2.frm shell> ln -s tbl1.MYD tbl2.MYD shell> ln -s tbl1.MYI tbl2.MYI Problems result if one thread reads `db1.tbl1' and another thread updates `db1.tbl2': * The query cache is `fooled' (it has no way of knowing that `tbl1' has not been updated, so it returns outdated results). * `ALTER' statements on `tbl2' fail.  File: manual.info, Node: windows-symbolic-links, Prev: symbolic-links-to-tables, Up: symbolic-links 8.9.6.3 Using Symbolic Links for Databases on Windows ..................................................... Symbolic links are enabled by default for all Windows servers. This enables you to put a database directory on a different disk by setting up a symbolic link to it. This is similar to the way that database symbolic links work on Unix, although the procedure for setting up the link is different. If you do not need symbolic links, you can disable them using the `--skip-symbolic-links' option. On Windows, create a symbolic link to a MySQL database by creating a file in the data directory that contains the path to the destination directory. The file should be named `DB_NAME.sym', where DB_NAME is the database name. Suppose that the MySQL data directory is `C:\mysql\data' and you want to have database `foo' located at `D:\data\foo'. Set up a symlink using this procedure 1. Make sure that the `D:\data\foo' directory exists by creating it if necessary. If you already have a database directory named `foo' in the data directory, you should move it to `D:\data'. Otherwise, the symbolic link will be ineffective. To avoid problems, make sure that the server is not running when you move the database directory. 2. Create a text file `C:\mysql\data\foo.sym' that contains the path name `D:\data\foo\'. *Note*: The path name to the new database and tables should be absolute. If you specify a relative path, the location will be relative to the `foo.sym' file. After this, all tables created in the database `foo' are created in `D:\data\foo'. The following limitations apply to the use of `.sym' files for database symbolic linking on Windows: * The symbolic link is not used if a directory with the same name as the database exists in the MySQL data directory. * The `--innodb_file_per_table' option cannot be used. * If you run *Note `mysqld': mysqld. as a service, you cannot use a mapped drive to a remote server as the destination of the symbolic link. As a workaround, you can use the full path (`\\servername\path\').  File: manual.info, Node: large-page-support, Next: dns, Prev: symbolic-links, Up: optimizing-the-server 8.9.7 Enabling Large Page Support --------------------------------- Some hardware/operating system architectures support memory pages greater than the default (usually 4KB). The actual implementation of this support depends on the underlying hardware and operating system. Applications that perform a lot of memory accesses may obtain performance improvements by using large pages due to reduced Translation Lookaside Buffer (TLB) misses. In MySQL, large pages can be used by InnoDB, to allocate memory for its buffer pool and additional memory pool. Currently, MySQL supports only the Linux implementation of large page support (which is called HugeTLB in Linux). Before large pages can be used on Linux, the kernel must be enabled to support them and it is necessary to configure the HugeTLB memory pool. For reference, the HugeTBL API is documented in the `Documentation/vm/hugetlbpage.txt' file of your Linux sources. The kernel for some recent systems such as Red Hat Enterprise Linux appear to have the large pages feature enabled by default. To check whether this is true for your kernel, use the following command and look for output lines containing `huge': shell> cat /proc/meminfo | grep -i huge HugePages_Total: 0 HugePages_Free: 0 HugePages_Rsvd: 0 HugePages_Surp: 0 Hugepagesize: 4096 kB The nonempty command output indicates that large page support is present, but the zero values indicate that no pages are configured for use. If your kernel needs to be reconfigured to support large pages, consult the `hugetlbpage.txt' file for instructions. Assuming that your Linux kernel has large page support enabled, configure it for use by MySQL using the following commands. Normally, you put these in an `rc' file or equivalent startup file that is executed during the system boot sequence, so that the commands execute each time the system starts. The commands should execute early in the boot sequence, before the MySQL server starts. Be sure to change the allocation numbers and the group number as appropriate for your system. # Set the number of pages to be used. # Each page is normally 2MB, so a value of 20 = 40MB. # This command actually allocates memory, so this much # memory must be available. echo 20 > /proc/sys/vm/nr_hugepages # Set the group number that is permitted to access this # memory (102 in this case). The mysql user must be a # member of this group. echo 102 > /proc/sys/vm/hugetlb_shm_group # Increase the amount of shmem permitted per segment # (12G in this case). echo 1560281088 > /proc/sys/kernel/shmmax # Increase total amount of shared memory. The value # is the number of pages. At 4KB/page, 4194304 = 16GB. echo 4194304 > /proc/sys/kernel/shmall For MySQL usage, you normally want the value of `shmmax' to be close to the value of `shmall'. To verify the large page configuration, check `/proc/meminfo' again as described previously. Now you should see some nonzero values: shell> cat /proc/meminfo | grep -i huge HugePages_Total: 20 HugePages_Free: 20 HugePages_Rsvd: 0 HugePages_Surp: 0 Hugepagesize: 4096 kB The final step to make use of the `hugetlb_shm_group' is to give the `mysql' user an `unlimited' value for the memlock limit. This can by done either by editing `/etc/security/limits.conf' or by adding the following command to your *Note `mysqld_safe': mysqld-safe. script: ulimit -l unlimited Adding the `ulimit' command to *Note `mysqld_safe': mysqld-safe. causes the `root' user to set the memlock limit to `unlimited' before switching to the `mysql' user. (This assumes that *Note `mysqld_safe': mysqld-safe. is started by `root'.) Large page support in MySQL is disabled by default. To enable it, start the server with the `--large-pages' option. For example, you can use the following lines in your server's `my.cnf' file: [mysqld] large-pages With this option, `InnoDB' uses large pages automatically for its buffer pool and additional memory pool. If `InnoDB' cannot do this, it falls back to use of traditional memory and writes a warning to the error log: `Warning: Using conventional memory pool' To verify that large pages are being used, check `/proc/meminfo' again: shell> cat /proc/meminfo | grep -i huge HugePages_Total: 20 HugePages_Free: 20 HugePages_Rsvd: 2 HugePages_Surp: 0 Hugepagesize: 4096 kB  File: manual.info, Node: dns, Prev: large-page-support, Up: optimizing-the-server 8.9.8 How MySQL Uses DNS ------------------------ When a new client connects to *Note `mysqld': mysqld, *Note `mysqld': mysqld. spawns a new thread to handle the request. This thread first checks whether the host name is in the host name cache. If not, the thread attempts to resolve the host name: * The thread takes the IP address and resolves it to a host name (using `gethostbyaddr()'). It then takes that host name and resolves it back to the IP address (using `gethostbyname()') and compares to ensure it is the original IP address. * If the operating system supports the thread-safe `gethostbyaddr_r()' and `gethostbyname_r()' calls, the thread uses them to perform host name resolution. * If the operating system does not support the thread-safe calls, the thread locks a mutex and calls `gethostbyaddr()' and `gethostbyname()' instead. In this case, no other thread can resolve host names that are not in the host name cache until the first thread unlocks the mutex. You can disable DNS host name lookups by starting *Note `mysqld': mysqld. with the `--skip-name-resolve' option. However, in this case, you can use only IP addresses in the MySQL grant tables. If you have a very slow DNS and many hosts, you can get more performance by either disabling DNS lookups with `--skip-name-resolve' or by increasing the `HOST_CACHE_SIZE' define (default value: 128) and recompiling *Note `mysqld': mysqld. You can disable the host name cache by starting the server with the `--skip-host-cache' option. To clear the host name cache, issue a *Note `FLUSH HOSTS': flush. statement or execute the *Note `mysqladmin flush-hosts': mysqladmin. command. To disallow TCP/IP connections entirely, start *Note `mysqld': mysqld. with the `--skip-networking' option.  File: manual.info, Node: thread-information, Prev: optimizing-the-server, Up: optimization 8.10 Examining Thread Information ================================= * Menu: * thread-commands:: Thread Command Values * general-thread-states:: General Thread States * delayed-insert-thread-states:: Delayed-Insert Thread States * query-cache-thread-states:: Query Cache Thread States * master-thread-states:: Replication Master Thread States * slave-io-thread-states:: Replication Slave I/O Thread States * slave-sql-thread-states:: Replication Slave SQL Thread States * slave-connection-thread-states:: Replication Slave Connection Thread States * mysql-cluster-thread-states:: MySQL Cluster Thread States * event-scheduler-thread-states:: Event Scheduler Thread States When you are attempting to ascertain what your MySQL server is doing, it can be helpful to examine the process list, which is the set of threads currently executing within the server. Process list information is available from these sources: * The `SHOW [FULL] PROCESSLIST' statement: *Note show-processlist:: * The *Note `SHOW PROFILE': show-profile. statement: *Note show-profiles:: * The `INFORMATION_SCHEMA' *Note `PROCESSLIST': processlist-table. table: *Note processlist-table:: * The *Note `mysqladmin processlist': mysqladmin. command: *Note mysqladmin:: You can always view information about your own threads. To view information about threads being executed for other accounts, you must have the `PROCESS' privilege. Each process list entry contains several pieces of information: * `Id' is the connection identifier for the client associated with the thread. * `User' and `Host' indicate the account associated with the thread. * `db' is the default database for the thread, or `NULL' if none is selected. * `Command' and `State' indicate what the thread is doing. Most states correspond to very quick operations. If a thread stays in a given state for many seconds, there might be a problem that needs to be investigated. * `Time' indicates how long the thread has been in its current state. The thread's notion of the current time may be altered in some cases: The thread can change the time with *Note `SET TIMESTAMP = VALUE': set-option. For a thread running on a slave that is processing events from the master, the thread time is set to the time found in the events and thus reflects current time on the master and not the slave. * `Info' contains the text of the statement being executed by the thread, or `NULL' if it is not executing one. By default, this value contains only the first 100 characters of the statement. To see the complete statements, use *Note `SHOW FULL PROCESSLIST': show-processlist. The following sections list the possible `Command' values, and `State' values grouped by category. The meaning for some of these values is self-evident. For others, additional description is provided.  File: manual.info, Node: thread-commands, Next: general-thread-states, Prev: thread-information, Up: thread-information 8.10.1 Thread Command Values ---------------------------- A thread can have any of the following `Command' values: * `Binlog Dump' This is a thread on a master server for sending binary log contents to a slave server. * `Change user' The thread is executing a change-user operation. * `Close stmt' The thread is closing a prepared statement. * `Connect' A replication slave is connected to its master. * `Connect Out' A replication slave is connecting to its master. * `Create DB' The thread is executing a create-database operation. * `Daemon' This thread is internal to the server, not a thread that services a client connection. * `Debug' The thread is generating debugging information. * `Delayed insert' The thread is a delayed-insert handler. * `Drop DB' The thread is executing a drop-database operation. * `Error' * `Execute' The thread is executing a prepared statement. * `Fetch' The thread is fetching the results from executing a prepared statement. * `Field List' The thread is retrieving information for table columns. * `Init DB' The thread is selecting a default database. * `Kill' The thread is killing another thread. * `Long Data' The thread is retrieving long data in the result of executing a prepared statement. * `Ping' The thread is handling a server-ping request. * `Prepare' The thread is preparing a prepared statement. * `Processlist' The thread is producing information about server threads. * `Query' The thread is executing a statement. * `Quit' The thread is terminating. * `Refresh' The thread is flushing table, logs, or caches, or resetting status variable or replication server information. * `Register Slave' The thread is registering a slave server. * `Reset stmt' The thread is resetting a prepared statement. * `Set option' The thread is setting or resetting a client statement-execution option. * `Shutdown' The thread is shutting down the server. * `Sleep' The thread is waiting for the client to send a new statement to it. * `Statistics' The thread is producing server-status information. * `Table Dump' The thread is sending table contents to a slave server. * `Time' Unused.  File: manual.info, Node: general-thread-states, Next: delayed-insert-thread-states, Prev: thread-commands, Up: thread-information 8.10.2 General Thread States ---------------------------- The following list describes thread `State' values that are associated with general query processing and not more specialized activities such as replication. Many of these are useful only for finding bugs in the server. * `After create' This occurs when the thread creates a table (including internal temporary tables), at the end of the function that creates the table. This state is used even if the table could not be created due to some error. * `Analyzing' The thread is calculating a `MyISAM' table key distributions (for example, for *Note `ANALYZE TABLE': analyze-table.). * `checking permissions' The thread is checking whether the server has the required privileges to execute the statement. * `Checking table' The thread is performing a table check operation. * `cleaning up' The thread has processed one command and is preparing to free memory and reset certain state variables. * `closing tables' The thread is flushing the changed table data to disk and closing the used tables. This should be a fast operation. If not, you should verify that you do not have a full disk and that the disk is not in very heavy use. * `converting HEAP to MyISAM' The thread is converting an internal temporary table from a `MEMORY' table to an on-disk `MyISAM' table. * `copy to tmp table' The thread is processing an *Note `ALTER TABLE': alter-table. statement. This state occurs after the table with the new structure has been created but before rows are copied into it. * `Copying to group table' If a statement has different `ORDER BY' and `GROUP BY' criteria, the rows are sorted by group and copied to a temporary table. * `Copying to tmp table' The server is copying to a temporary table in memory. * `Copying to tmp table on disk' The server is copying to a temporary table on disk. The temporary result set has become too large (see *Note internal-temporary-tables::). Consequently, the thread is changing the temporary table from in-memory to disk-based format to save memory. * `Creating index' The thread is processing `ALTER TABLE ... ENABLE KEYS' for a `MyISAM' table. * `Creating sort index' The thread is processing a *Note `SELECT': select. that is resolved using an internal temporary table. * `creating table' The thread is creating a table. This includes creation of temporary tables. * `Creating tmp table' The thread is creating a temporary table in memory or on disk. If the table is created in memory but later is converted to an on-disk table, the state during that operation will be `Copying to tmp table on disk'. * `deleting from main table' The server is executing the first part of a multiple-table delete. It is deleting only from the first table, and saving columns and offsets to be used for deleting from the other (reference) tables. * `deleting from reference tables' The server is executing the second part of a multiple-table delete and deleting the matched rows from the other tables. * `discard_or_import_tablespace' The thread is processing an `ALTER TABLE ... DISCARD TABLESPACE' or `ALTER TABLE ... IMPORT TABLESPACE' statement. * `end' This occurs at the end but before the cleanup of *Note `ALTER TABLE': alter-table, *Note `CREATE VIEW': create-view, *Note `DELETE': delete, *Note `INSERT': insert, *Note `SELECT': select, or *Note `UPDATE': update. statements. * `executing' The thread has begun executing a statement. * `Execution of init_command' The thread is executing statements in the value of the `init_command' system variable. * `freeing items' The thread has executed a command. Some freeing of items done during this state involves the query cache. This state is usually followed by `cleaning up'. * `Flushing tables' The thread is executing *Note `FLUSH TABLES': flush. and is waiting for all threads to close their tables. * `FULLTEXT initialization' The server is preparing to perform a natural-language full-text search. * `init' This occurs before the initialization of *Note `ALTER TABLE': alter-table, *Note `DELETE': delete, *Note `INSERT': insert, *Note `SELECT': select, or *Note `UPDATE': update. statements. Actions taken by the server in this state include flushing the binary log, the `InnoDB' log, and some query cache cleanup operations. For the `end' state, the following operations could be happening: * Removing query cache entries after data in a table is changed * Writing an event to the binary log * Freeing memory buffers, including for blobs * `Killed' Someone has sent a *Note `KILL': kill. statement to the thread and it should abort next time it checks the kill flag. The flag is checked in each major loop in MySQL, but in some cases it might still take a short time for the thread to die. If the thread is locked by some other thread, the kill takes effect as soon as the other thread releases its lock. * `Locked' The query is locked by another query. * `logging slow query' The thread is writing a statement to the slow-query log. * `NULL' This state is used for the *Note `SHOW PROCESSLIST': show-processlist. state. * `login' The initial state for a connection thread until the client has been authenticated successfully. * `manage keys' The server is enabling or disabling a table index. * `Opening tables', `Opening table' The thread is trying to open a table. This is should be very fast procedure, unless something prevents opening. For example, an *Note `ALTER TABLE': alter-table. or a *Note `LOCK TABLE': lock-tables. statement can prevent opening a table until the statement is finished. It is also worth checking that your `table_open_cache' value is large enough. * `optimizing' The server is performing initial optimizations for a query. * `preparing' This state occurs during query optimization. * `Purging old relay logs' The thread is removing unneeded relay log files. * `query end' This state occurs after processing a query but before the `freeing items' state. * `Reading from net' The server is reading a packet from the network. * `Removing duplicates' The query was using *Note `SELECT DISTINCT': select. in such a way that MySQL could not optimize away the distinct operation at an early stage. Because of this, MySQL requires an extra stage to remove all duplicated rows before sending the result to the client. * `removing tmp table' The thread is removing an internal temporary table after processing a *Note `SELECT': select. statement. This state is not used if no temporary table was created. * `rename' The thread is renaming a table. * `rename result table' The thread is processing an *Note `ALTER TABLE': alter-table. statement, has created the new table, and is renaming it to replace the original table. * `Reopen tables' The thread got a lock for the table, but noticed after getting the lock that the underlying table structure changed. It has freed the lock, closed the table, and is trying to reopen it. * `Repair by sorting' The repair code is using a sort to create indexes. * `Repair done' The thread has completed a multi-threaded repair for a `MyISAM' table. * `Repair with keycache' The repair code is using creating keys one by one through the key cache. This is much slower than `Repair by sorting'. * `Rolling back' The thread is rolling back a transaction. * `Saving state' For `MyISAM' table operations such as repair or analysis, the thread is saving the new table state to the `.MYI' file header. State includes information such as number of rows, the `AUTO_INCREMENT' counter, and key distributions. * `Searching rows for update' The thread is doing a first phase to find all matching rows before updating them. This has to be done if the *Note `UPDATE': update. is changing the index that is used to find the involved rows. * `Sending data' The thread is reading and processing rows for a *Note `SELECT': select. statement, and sending data to the client. Because operations occurring during this this state tend to perform large amounts of disk access (reads), it is often the longest-running state over the lifetime of a given query. * `setup' The thread is beginning an *Note `ALTER TABLE': alter-table. operation. * `Sorting for group' The thread is doing a sort to satisfy a `GROUP BY'. * `Sorting for order' The thread is doing a sort to satisfy a `ORDER BY'. * `Sorting index' The thread is sorting index pages for more efficient access during a `MyISAM' table optimization operation. * `Sorting result' For a *Note `SELECT': select. statement, this is similar to `Creating sort index', but for nontemporary tables. * `statistics' The server is calculating statistics to develop a query execution plan. If a thread is in this state for a long time, the server is probably disk-bound performing other work. * `System lock' The thread is going to request or is waiting for an internal or external system lock for the table. If this state is being caused by requests for external locks and you are not using multiple *Note `mysqld': mysqld. servers that are accessing the same *Note `MyISAM': myisam-storage-engine. tables, you can disable external system locks with the `--skip-external-locking' option. However, external locking is disabled by default, so it is likely that this option will have no effect. * `Table lock' The next thread state after `System lock'. The thread has acquired an external lock and is going to request an internal table lock. * `Updating' The thread is searching for rows to update and is updating them. * `updating main table' The server is executing the first part of a multiple-table update. It is updating only the first table, and saving columns and offsets to be used for updating the other (reference) tables. * `updating reference tables' The server is executing the second part of a multiple-table update and updating the matched rows from the other tables. * `User lock' The thread is going to request or is waiting for an advisory lock requested with a `GET_LOCK()' call. For *Note `SHOW PROFILE': show-profile, this state means the thread is requesting the lock (not waiting for it). * `User sleep' The thread has invoked a `SLEEP()' call. * `Waiting for release of readlock' The thread is waiting for a global read lock obtained by another thread (with *Note `FLUSH TABLES WITH READ LOCK': flush.) to be released. * `Waiting for tables', `Waiting for table' The thread got a notification that the underlying structure for a table has changed and it needs to reopen the table to get the new structure. However, to reopen the table, it must wait until all other threads have closed the table in question. This notification takes place if another thread has used *Note `FLUSH TABLES': flush. or one of the following statements on the table in question: `FLUSH TABLES TBL_NAME', *Note `ALTER TABLE': alter-table, *Note `RENAME TABLE': rename-table, *Note `REPAIR TABLE': repair-table, *Note `ANALYZE TABLE': analyze-table, or *Note `OPTIMIZE TABLE': optimize-table. * `Waiting on cond' A generic state in which the thread is waiting for a condition to become true. No specific state information is available. * `Waiting to get readlock' The thread has issued a *Note `FLUSH TABLES WITH READ LOCK': flush. statement to obtain a global read lock and is waiting to obtain the lock. * `Writing to net' The server is writing a packet to the network.  File: manual.info, Node: delayed-insert-thread-states, Next: query-cache-thread-states, Prev: general-thread-states, Up: thread-information 8.10.3 Delayed-Insert Thread States ----------------------------------- These thread states are associated with processing for `DELAYED' inserts (see *Note insert-delayed::). Some states are associated with connection threads that process *Note `INSERT DELAYED': insert-delayed. statements from clients. Other states are associated with delayed-insert handler threads that insert the rows. There is a delayed-insert handler thread for each table for which *Note `INSERT DELAYED': insert-delayed. statements are issued. States associated with a connection thread that processes an *Note `INSERT DELAYED': insert-delayed. statement from the client: * `allocating local table' The thread is preparing to feed rows to the delayed-insert handler thread. * `Creating delayed handler' The thread is creating a handler for `DELAYED' inserts. * `got handler lock' This occurs before the `allocating local table' state and after the `waiting for handler lock' state, when the connection thread gets access to the delayed-insert handler thread. * `got old table' This occurs after the `waiting for handler open' state. The delayed-insert handler thread has signaled that it has ended its initialization phase, which includes opening the table for delayed inserts. * `storing row into queue' The thread is adding a new row to the list of rows that the delayed-insert handler thread must insert. * `update' The thread is getting ready to start updating the table. * `waiting for delay_list' This occurs during the initialization phase when the thread is trying to find the delayed-insert handler thread for the table, and before attempting to gain access to the list of delayed-insert threads. * `waiting for handler insert' An *Note `INSERT DELAYED': insert-delayed. handler has processed all pending inserts and is waiting for new ones. * `waiting for handler lock' This occurs before the `allocating local table' state when the connection thread waits for access to the delayed-insert handler thread. * `waiting for handler open' This occurs after the `Creating delayed handler' state and before the `got old table' state. The delayed-insert handler thread has just been started, and the connection thread is waiting for it to initialize. States associated with a delayed-insert handler thread that inserts the rows: * `insert' The state that occurs just before inserting rows into the table. * `reschedule' After inserting a number of rows, the delayed-insert thread sleeps to let other threads do work. * `upgrading lock' A delayed-insert handler is trying to get a lock for the table to insert rows. * `Waiting for INSERT' A delayed-insert handler is waiting for a connection thread to add rows to the queue (see `storing row into queue').  File: manual.info, Node: query-cache-thread-states, Next: master-thread-states, Prev: delayed-insert-thread-states, Up: thread-information 8.10.4 Query Cache Thread States -------------------------------- These thread states are associated with the query cache (see *Note query-cache::). * `checking privileges on cached query' The server is checking whether the user has privileges to access a cached query result. * `checking query cache for query' The server is checking whether the current query is present in the query cache. * `invalidating query cache entries' Query cache entries are being marked invalid because the underlying tables have changed. * `sending cached result to client' The server is taking the result of a query from the query cache and sending it to the client. * `storing result in query cache' The server is storing the result of a query in the query cache.  File: manual.info, Node: master-thread-states, Next: slave-io-thread-states, Prev: query-cache-thread-states, Up: thread-information 8.10.5 Replication Master Thread States --------------------------------------- The following list shows the most common states you may see in the `State' column for the master's `Binlog Dump' thread. If you see no `Binlog Dump' threads on a master server, this means that replication is not running--that is, that no slaves are currently connected. * `Sending binlog event to slave' Binary logs consist of _events_, where an event is usually an update plus some other information. The thread has read an event from the binary log and is now sending it to the slave. * `Finished reading one binlog; switching to next binlog' The thread has finished reading a binary log file and is opening the next one to send to the slave. * `Has sent all binlog to slave; waiting for binlog to be updated' The thread has read all outstanding updates from the binary logs and sent them to the slave. The thread is now idle, waiting for new events to appear in the binary log resulting from new updates occurring on the master. * `Waiting to finalize termination' A very brief state that occurs as the thread is stopping.  File: manual.info, Node: slave-io-thread-states, Next: slave-sql-thread-states, Prev: master-thread-states, Up: thread-information 8.10.6 Replication Slave I/O Thread States ------------------------------------------ The following list shows the most common states you see in the `State' column for a slave server I/O thread. This state also appears in the `Slave_IO_State' column displayed by *Note `SHOW SLAVE STATUS': show-slave-status, so you can get a good view of what is happening by using that statement. * `Waiting for master update' The initial state before `Connecting to master'. * `Connecting to master' The thread is attempting to connect to the master. * `Checking master version' A state that occurs very briefly, after the connection to the master is established. * `Registering slave on master' A state that occurs very briefly after the connection to the master is established. * `Requesting binlog dump' A state that occurs very briefly, after the connection to the master is established. The thread sends to the master a request for the contents of its binary logs, starting from the requested binary log file name and position. * `Waiting to reconnect after a failed binlog dump request' If the binary log dump request failed (due to disconnection), the thread goes into this state while it sleeps, then tries to reconnect periodically. The interval between retries can be specified using the *Note `CHANGE MASTER TO': change-master-to. statement or the `--master-connect-retry' option. * `Reconnecting after a failed binlog dump request' The thread is trying to reconnect to the master. * `Waiting for master to send event' The thread has connected to the master and is waiting for binary log events to arrive. This can last for a long time if the master is idle. If the wait lasts for `slave_net_timeout' seconds, a timeout occurs. At that point, the thread considers the connection to be broken and makes an attempt to reconnect. * `Queueing master event to the relay log' The thread has read an event and is copying it to the relay log so that the SQL thread can process it. * `Waiting to reconnect after a failed master event read' An error occurred while reading (due to disconnection). The thread is sleeping for the number of seconds set by the *Note `CHANGE MASTER TO': change-master-to. statement or `--master-connect-retry' option (default 60) before attempting to reconnect. * `Reconnecting after a failed master event read' The thread is trying to reconnect to the master. When connection is established again, the state becomes `Waiting for master to send event'. * `Waiting for the slave SQL thread to free enough relay log space' You are using a nonzero `relay_log_space_limit' value, and the relay logs have grown large enough that their combined size exceeds this value. The I/O thread is waiting until the SQL thread frees enough space by processing relay log contents so that it can delete some relay log files. * `Waiting for slave mutex on exit' A state that occurs briefly as the thread is stopping.  File: manual.info, Node: slave-sql-thread-states, Next: slave-connection-thread-states, Prev: slave-io-thread-states, Up: thread-information 8.10.7 Replication Slave SQL Thread States ------------------------------------------ The following list shows the most common states you may see in the `State' column for a slave server SQL thread: * `Waiting for the next event in relay log' The initial state before `Reading event from the relay log'. * `Reading event from the relay log' The thread has read an event from the relay log so that the event can be processed. * `Has read all relay log; waiting for the slave I/O thread to update it' The thread has processed all events in the relay log files, and is now waiting for the I/O thread to write new events to the relay log. * `Making temp file' The thread is executing a *Note `LOAD DATA INFILE': load-data. statement and is creating a temporary file containing the data from which the slave will read rows. * `Waiting for slave mutex on exit' A very brief state that occurs as the thread is stopping. The `State' column for the I/O thread may also show the text of a statement. This indicates that the thread has read an event from the relay log, extracted the statement from it, and is executing it.  File: manual.info, Node: slave-connection-thread-states, Next: mysql-cluster-thread-states, Prev: slave-sql-thread-states, Up: thread-information 8.10.8 Replication Slave Connection Thread States ------------------------------------------------- These thread states occur on a replication slave but are associated with connection threads, not with the I/O or SQL threads. * `Changing master' The thread is processing a *Note `CHANGE MASTER TO': change-master-to. statement. * `Creating table from master dump' The slave is creating a table using the *Note `CREATE TABLE': create-table. statement contained in the dump from the master. Used for *Note `LOAD TABLE FROM MASTER': load-table-from-master. and *Note `LOAD DATA FROM MASTER': load-data-from-master. * `Killing slave' The thread is processing a `STOP SLAVE' statement. * `Opening master dump table' This state occurs after `Creating table from master dump'. * `Reading master dump table data' This state occurs after `Opening master dump table'. * `Rebuilding the index on master dump table' This state occurs after `Reading master dump table data'. * `starting slave' The thread is starting the slave threads after processing a successful *Note `LOAD DATA FROM MASTER': load-data-from-master. load operation.  File: manual.info, Node: mysql-cluster-thread-states, Next: event-scheduler-thread-states, Prev: slave-connection-thread-states, Up: thread-information 8.10.9 MySQL Cluster Thread States ---------------------------------- * `Committing events to binlog' * `Opening mysql.ndb_apply_status' * `Processing events' The thread is processing events for binary logging. * `Processing events from schema table' The thread is doing the work of schema replication. * `Shutting down' * `Syncing ndb table schema operation and binlog' This is used to have a correct binary log of schema operations for NDB. * `Waiting for event from ndbcluster' The server is acting as an SQL node in a MySQL Cluster, and is connected to a cluster management node. * `Waiting for first event from ndbcluster' * `Waiting for ndbcluster binlog update to reach current position' * `Waiting for ndbcluster to start' * `Waiting for schema epoch' The thread is waiting for a schema epoch (that is, a global checkpoint).  File: manual.info, Node: event-scheduler-thread-states, Prev: mysql-cluster-thread-states, Up: thread-information 8.10.10 Event Scheduler Thread States ------------------------------------- These states occur for the Event Scheduler thread, threads that are created to execute scheduled events, or threads that terminate the scheduler. * `Clearing' The scheduler thread or a thread that was executing an event is terminating and is about to end. * `Initialized' The scheduler thread or a thread that will execute an event has been initialized. * `Waiting for next activation' The scheduler has a nonempty event queue but the next activation is in the future. * `Waiting for scheduler to stop' The thread issued `SET GLOBAL event_scheduler=OFF' and is waiting for the scheduler to stop. * `Waiting on empty queue' The scheduler's event queue is empty and it is sleeping.  File: manual.info, Node: language-structure, Next: globalization, Prev: optimization, Up: Top 9 Language Structure ******************** * Menu: * literals:: Literal Values * identifiers:: Schema Object Names * reserved-words:: Reserved Words * user-variables:: User-Defined Variables * expressions:: Expression Syntax * comments:: Comment Syntax This chapter discusses the rules for writing the following elements of SQL statements when using MySQL: * Literal values such as strings and numbers * Identifiers such as database, table, and column names * Reserved words * User-defined and system variables * Comments  File: manual.info, Node: literals, Next: identifiers, Prev: language-structure, Up: language-structure 9.1 Literal Values ================== * Menu: * string-syntax:: Strings * number-syntax:: Numbers * date-and-time-values:: Date and Time Values * hexadecimal-values:: Hexadecimal Values * boolean-values:: Boolean Values * bit-field-values:: Bit-Field Values * null-values:: `NULL' Values This section describes how to write literal values in MySQL. These include strings, numbers, hexadecimal values, boolean values, and `NULL'. The section also covers the various nuances and `gotchas' that you may run into when dealing with these basic types in MySQL.  File: manual.info, Node: string-syntax, Next: number-syntax, Prev: literals, Up: literals 9.1.1 Strings ------------- A string is a sequence of bytes or characters, enclosed within either single quote (``''') or double quote (``"'') characters. Examples: 'a string' "another string" Quoted strings placed next to each other are concatenated to a single string. The following lines are equivalent: 'a string' 'a' ' ' 'string' If the `ANSI_QUOTES' SQL mode is enabled, string literals can be quoted only within single quotation marks because a string quoted within double quotation marks is interpreted as an identifier. A _binary string_ is a string of bytes that has no character set or collation. A _nonbinary string_ is a string of characters that has a character set and collation. For both types of strings, comparisons are based on the numeric values of the string unit. For binary strings, the unit is the byte. For nonbinary strings the unit is the character and some character sets support multi-byte characters. Character value ordering is a function of the string collation. String literals may have an optional character set introducer and `COLLATE' clause: [_CHARSET_NAME]'STRING' [COLLATE COLLATION_NAME] Examples: SELECT _latin1'STRING'; SELECT _latin1'STRING' COLLATE latin1_danish_ci; You can use `N'LITERAL'' (or `n'LITERAL'') to create a string in the national character set. These statements are equivalent: SELECT N'some text'; SELECT n'some text'; SELECT _utf8'some text'; For more information about these forms of string syntax, see *Note charset-literal::, and *Note charset-national::. Within a string, certain sequences have special meaning unless the `NO_BACKSLASH_ESCAPES' SQL mode is enabled. Each of these sequences begins with a backslash (``\''), known as the _escape character_. MySQL recognizes the following escape sequences. Character Escape Sequence `\0' An ASCII NUL (`0x00') character. `\'' A single quote (``''') character. `\"' A double quote (``"'') character. `\b' A backspace character. `\n' A newline (linefeed) character. `\r' A carriage return character. `\t' A tab character. `\Z' ASCII 26 (Control+Z). See note following the table. `\\' A backslash (``\'') character. `\%' A ``%'' character. See note following the table. `\_' A ``_'' character. See note following the table. For all other escape sequences, backslash is ignored. That is, the escaped character is interpreted as if it was not escaped. For example, ``\x'' is just ``x''. These sequences are case sensitive. For example, ``\b'' is interpreted as a backspace, but ``\B'' is interpreted as ``B''. The ASCII 26 character can be encoded as ``\Z'' to enable you to work around the problem that ASCII 26 stands for END-OF-FILE on Windows. ASCII 26 within a file causes problems if you try to use `mysql DB_NAME < FILE_NAME'. Escape processing is done according to the character set indicated by the `character_set_connection' system variable. This is true even for strings that are preceded by an introducer that indicates a different character set, as discussed in *Note charset-literal::. The ``\%'' and ``\_'' sequences are used to search for literal instances of ``%'' and ``_'' in pattern-matching contexts where they would otherwise be interpreted as wildcard characters. See the description of the `LIKE' operator in *Note string-comparison-functions::. If you use ``\%'' or ``\_'' outside of pattern-matching contexts, they evaluate to the strings ``\%'' and ``\_'', not to ``%'' and ``_''. There are several ways to include quote characters within a string: * A ``''' inside a string quoted with ``''' may be written as ``''''. * A ``"'' inside a string quoted with ``"'' may be written as ``""''. * Precede the quote character by an escape character (``\''). * A ``''' inside a string quoted with ``"'' needs no special treatment and need not be doubled or escaped. In the same way, ``"'' inside a string quoted with ``''' needs no special treatment. The following *Note `SELECT': select. statements demonstrate how quoting and escaping work: mysql> SELECT 'hello', '"hello"', '""hello""', 'hel''lo', '\'hello'; +-------+---------+-----------+--------+--------+ | hello | "hello" | ""hello"" | hel'lo | 'hello | +-------+---------+-----------+--------+--------+ mysql> SELECT "hello", "'hello'", "''hello''", "hel""lo", "\"hello"; +-------+---------+-----------+--------+--------+ | hello | 'hello' | ''hello'' | hel"lo | "hello | +-------+---------+-----------+--------+--------+ mysql> SELECT 'This\nIs\nFour\nLines'; +--------------------+ | This Is Four Lines | +--------------------+ mysql> SELECT 'disappearing\ backslash'; +------------------------+ | disappearing backslash | +------------------------+ If you want to insert binary data into a string column (such as a *Note `BLOB': blob. column), the following characters must be represented by escape sequences. Character Escape Sequence `NUL' `NUL' byte (`0x00'). Represent this character by ``\0'' (a backslash followed by an ASCII ``0'' character). `\' Backslash (ASCII 92). Represent this character by ``\\''. `'' Single quote (ASCII 39). Represent this character by ``\'''. `"' Double quote (ASCII 34). Represent this character by ``\"''. When writing application programs, any string that might contain any of these special characters must be properly escaped before the string is used as a data value in an SQL statement that is sent to the MySQL server. You can do this in two ways: * Process the string with a function that escapes the special characters. In a C program, you can use the *Note `mysql_real_escape_string()': mysql-real-escape-string. C API function to escape characters. See *Note mysql-real-escape-string::. The Perl DBI interface provides a `quote' method to convert special characters to the proper escape sequences. See *Note apis-perl::. Other language interfaces may provide a similar capability. * As an alternative to explicitly escaping special characters, many MySQL APIs provide a placeholder capability that enables you to insert special markers into a statement string, and then bind data values to them when you issue the statement. In this case, the API takes care of escaping special characters in the values for you.  File: manual.info, Node: number-syntax, Next: date-and-time-values, Prev: string-syntax, Up: literals 9.1.2 Numbers ------------- Integers are represented as a sequence of digits. Floats use ``.'' as a decimal separator. Either type of number may be preceded by ``-'' or ``+'' to indicate a negative or positive value, respectively Examples of valid integers: 1221 0 -32 Examples of valid floating-point numbers: 294.42 -32032.6809e+10 148.00 An integer may be used in a floating-point context; it is interpreted as the equivalent floating-point number.  File: manual.info, Node: date-and-time-values, Next: hexadecimal-values, Prev: number-syntax, Up: literals 9.1.3 Date and Time Values -------------------------- Date and time values can be represented as quoted strings or as numbers, depending on the exact type of the value and other factors. For specific information about the formats used to represent *Note `DATE': datetime, *Note `DATETIME': datetime, and *Note `TIMESTAMP': datetime. values, see *Note datetime::. For specific information about the formats used to represent *Note `TIME': time. values, see *Note time::. For specific information about the formats used to represent *Note `YEAR': year. values, see *Note year::.  File: manual.info, Node: hexadecimal-values, Next: boolean-values, Prev: date-and-time-values, Up: literals 9.1.4 Hexadecimal Values ------------------------ MySQL supports hexadecimal values, written using `X'VAL'', `x'VAL'', or `0xVAL' format, where VAL contains hexadecimal digits (`0..9', `A..F'). Lettercase of the digits does not matter. For values written using `X'VAL'' or `x'VAL'' format, VAL must contain an even number of digits. For values written using `0xVAL syntax', values that contain an odd number of digits are treated as having an extra leading `0'. For example, `0x0a' and `0xaaa' are interpreted as `0x0a' and `0x0aaa'. In numeric contexts, hexadecimal values act like integers (64-bit precision). In string contexts, they act like binary strings, where each pair of hex digits is converted to a character: mysql> SELECT X'4D7953514C'; -> 'MySQL' mysql> SELECT 0x0a+0; -> 10 mysql> SELECT 0x5061756c; -> 'Paul' The default type of a hexadecimal value is a string. If you want to ensure that the value is treated as a number, you can use `CAST(... AS UNSIGNED)': mysql> SELECT 0x41, CAST(0x41 AS UNSIGNED); -> 'A', 65 The `X'HEXSTRING'' syntax is based on standard SQL. The `0x' syntax is based on ODBC. Hexadecimal strings are often used by ODBC to supply values for *Note `BLOB': blob. columns. You can convert a string or a number to a string in hexadecimal format with the `HEX()' function: mysql> SELECT HEX('cat'); -> '636174' mysql> SELECT 0x636174; -> 'cat'  File: manual.info, Node: boolean-values, Next: bit-field-values, Prev: hexadecimal-values, Up: literals 9.1.5 Boolean Values -------------------- The constants `TRUE' and `FALSE' evaluate to `1' and `0', respectively. The constant names can be written in any lettercase. mysql> SELECT TRUE, true, FALSE, false; -> 1, 1, 0, 0  File: manual.info, Node: bit-field-values, Next: null-values, Prev: boolean-values, Up: literals 9.1.6 Bit-Field Values ---------------------- Bit-field values can be written using `b'VALUE'' or `0bVALUE' notation. VALUE is a binary value written using zeros and ones. Bit-field notation is convenient for specifying values to be assigned to *Note `BIT': numeric-types. columns: mysql> CREATE TABLE t (b BIT(8)); mysql> INSERT INTO t SET b = b'11111111'; mysql> INSERT INTO t SET b = b'1010'; mysql> INSERT INTO t SET b = b'0101'; Bit values are returned as binary values. To display them in printable form, add 0 or use a conversion function such as `BIN()'. High-order 0 bits are not displayed in the converted value. mysql> SELECT b+0, BIN(b+0), OCT(b+0), HEX(b+0) FROM t; +------+----------+----------+----------+ | b+0 | BIN(b+0) | OCT(b+0) | HEX(b+0) | +------+----------+----------+----------+ | 255 | 11111111 | 377 | FF | | 10 | 1010 | 12 | A | | 5 | 101 | 5 | 5 | +------+----------+----------+----------+ Bit values assigned to user variables are treated as binary strings. To assign a bit value as a number to a user variable, use `CAST()' or `+0': mysql> SET @v1 = 0b1000001; mysql> SET @v2 = CAST(0b1000001 AS UNSIGNED), @v3 = 0b1000001+0; mysql> SELECT @v1, @v2, @v3; +------+------+------+ | @v1 | @v2 | @v3 | +------+------+------+ | A | 65 | 65 | +------+------+------+  File: manual.info, Node: null-values, Prev: bit-field-values, Up: literals 9.1.7 `NULL' Values ------------------- The `NULL' value means `no data.' `NULL' can be written in any lettercase. A synonym is `\N' (case sensitive). For text file import or export operations performed with *Note `LOAD DATA INFILE': load-data. or *Note `SELECT ... INTO OUTFILE': select, `NULL' is represented by the `\N' sequence. See *Note load-data::. Be aware that the `NULL' value is different from values such as `0' for numeric types or the empty string for string types. For more information, see *Note problems-with-null::.  File: manual.info, Node: identifiers, Next: reserved-words, Prev: literals, Up: language-structure 9.2 Schema Object Names ======================= * Menu: * identifier-qualifiers:: Identifier Qualifiers * identifier-case-sensitivity:: Identifier Case Sensitivity * identifier-mapping:: Mapping of Identifiers to File Names * function-resolution:: Function Name Parsing and Resolution Certain objects within MySQL, including database, table, index, column, alias, view, stored procedure, partition, tablespace, and other object names are known as identifiers. This section describes the permissible syntax for identifiers in MySQL. *Note identifier-case-sensitivity::, describes which types of identifiers are case sensitive and under what conditions. An identifier may be quoted or unquoted. If an identifier contains special characters or is a reserved word, you _must_ quote it whenever you refer to it. (Exception: A reserved word that follows a period in a qualified name must be an identifier, so it need not be quoted.) Reserved words are listed at *Note reserved-words::. Identifiers are converted to Unicode internally. They may contain these characters: * Permitted characters in unquoted identifiers: * ASCII: [0-9,a-z,A-Z$_] (basic Latin letters, digits 0-9, dollar, underscore) * Extended: U+0080 .. U+FFFF * Permitted characters in quoted identifiers include the full Unicode Basic Multilingual Plane (BMP), except U+0000: * ASCII: U+0001 .. U+007F * Extended: U+0080 .. U+FFFF * ASCII NUL (U+0000) and supplementary characters (U+10000 and higher) are not permitted in quoted or unquoted identifiers. * Identifiers may begin with a digit but unless quoted may not consist solely of digits. * Database, table, and column names cannot end with space characters. * Before MySQL 5.1.6, database and table names cannot contain ``/'', ``\'', ``.'', or characters that are not permitted in file names. The identifier quote character is the backtick (```''): mysql> SELECT * FROM `select` WHERE `select`.id > 100; If the `ANSI_QUOTES' SQL mode is enabled, it is also permissible to quote identifiers within double quotation marks: mysql> CREATE TABLE "test" (col INT); ERROR 1064: You have an error in your SQL syntax... mysql> SET sql_mode='ANSI_QUOTES'; mysql> CREATE TABLE "test" (col INT); Query OK, 0 rows affected (0.00 sec) The `ANSI_QUOTES' mode causes the server to interpret double-quoted strings as identifiers. Consequently, when this mode is enabled, string literals must be enclosed within single quotation marks. They cannot be enclosed within double quotation marks. The server SQL mode is controlled as described in *Note server-sql-mode::. Identifier quote characters can be included within an identifier if you quote the identifier. If the character to be included within the identifier is the same as that used to quote the identifier itself, then you need to double the character. The following statement creates a table named `a`b' that contains a column named `c"d': mysql> CREATE TABLE `a``b` (`c"d` INT); In the select list of a query, a quoted column alias can be specified using identifier or string quoting characters: mysql> SELECT 1 AS `one`, 2 AS 'two'; +-----+-----+ | one | two | +-----+-----+ | 1 | 2 | +-----+-----+ Elsewhere in the statement, quoted references to the alias must use identifier quoting or the reference is treated as a string literal. It is recommended that you do not use names that begin with `Me' or `MeN', where M and N are integers. For example, avoid using `1e' as an identifier, because an expression such as `1e+3' is ambiguous. Depending on context, it might be interpreted as the expression `1e + 3' or as the number `1e+3'. Be careful when using `MD5()' to produce table names because it can produce names in illegal or ambiguous formats such as those just described. A user variable cannot be used directly in an SQL statement as an identifier or as part of an identifier. See *Note user-variables::, for more information and examples of workarounds. As of MySQL 5.1.6, special characters in database and table names are encoded in the corresponding file system names as described in *Note identifier-mapping::. If you have databases or tables from an older version of MySQL that contain special characters and for which the underlying directory names or file names have not been updated to use the new encoding, the server displays their names with a prefix of `#mysql50#'. For information about referring to such names or converting them to the newer encoding, see that section. The following table describes the maximum length for each type of identifier. Identifier Maximum Length (characters) Database 64 Table 64 Column 64 Index 64 Constraint 64 Stored 64 Procedure or Function Trigger 64 View 64 Event 64 Tablespace 64 Server 64 Log File 64 Group Alias 256 (see exception following table) Compound 16 Statement Label As of MySQL 5.1.23, aliases for column names in *Note `CREATE VIEW': create-view. statements are checked against the maximum column length of 64 characters (not the maximum alias length of 256 characters). Identifiers are stored using Unicode (UTF-8). This applies to identifiers in table definitions that are stored in `.frm' files and to identifiers stored in the grant tables in the `mysql' database. The sizes of the identifier string columns in the grant tables are measured in characters. You can use multi-byte characters without reducing the number of characters permitted for values stored in these columns, something not true prior to MySQL 4.1. As indicated earlier, the permissible Unicode characters are those in the Basic Multilingual Plane (BMP). Supplementary characters are not permitted.  File: manual.info, Node: identifier-qualifiers, Next: identifier-case-sensitivity, Prev: identifiers, Up: identifiers 9.2.1 Identifier Qualifiers --------------------------- MySQL permits names that consist of a single identifier or multiple identifiers. The components of a multiple-part name must be separated by period (``.'') characters. The initial parts of a multiple-part name act as qualifiers that affect the context within which the final identifier is interpreted. In MySQL, you can refer to a table column using any of the following forms. Column Reference Meaning COL_NAME The column COL_NAME from whichever table used in the statement contains a column of that name. TBL_NAME.COL_NAME The column COL_NAME from table TBL_NAME of the default database. DB_NAME.TBL_NAME.COL_NAMEThe column COL_NAME from table TBL_NAME of the database DB_NAME. If any components of a multiple-part name require quoting, quote them individually rather than quoting the name as a whole. For example, write ``my-table`.`my-column`', not ``my-table.my-column`'. A reserved word that follows a period in a qualified name must be an identifier, so in that context it need not be quoted. You need not specify a TBL_NAME or DB_NAME.TBL_NAME prefix for a column reference in a statement unless the reference would be ambiguous. Suppose that tables `t1' and `t2' each contain a column `c', and you retrieve `c' in a *Note `SELECT': select. statement that uses both `t1' and `t2'. In this case, `c' is ambiguous because it is not unique among the tables used in the statement. You must qualify it with a table name as `t1.c' or `t2.c' to indicate which table you mean. Similarly, to retrieve from a table `t' in database `db1' and from a table `t' in database `db2' in the same statement, you must refer to columns in those tables as `db1.t.COL_NAME' and `db2.t.COL_NAME'. The syntax `.TBL_NAME' means the table TBL_NAME in the default database. This syntax is accepted for ODBC compatibility because some ODBC programs prefix table names with a ``.'' character.  File: manual.info, Node: identifier-case-sensitivity, Next: identifier-mapping, Prev: identifier-qualifiers, Up: identifiers 9.2.2 Identifier Case Sensitivity --------------------------------- In MySQL, databases correspond to directories within the data directory. Each table within a database corresponds to at least one file within the database directory (and possibly more, depending on the storage engine). Triggers also correspond to files. Consequently, the case sensitivity of the underlying operating system plays a part in the case sensitivity of database, table, and trigger names. This means such names are not case sensitive in Windows, but are case sensitive in most varieties of Unix. One notable exception is Mac OS X, which is Unix-based but uses a default file system type (HFS+) that is not case sensitive. However, Mac OS X also supports UFS volumes, which are case sensitive just as on any Unix. See *Note extensions-to-ansi::. The `lower_case_table_names' system variable also affects how the server handles identifier case sensitivity, as described later in this section. *Note*: Although database, table, and trigger names are not case sensitive on some platforms, you should not refer to one of these using different cases within the same statement. The following statement would not work because it refers to a table both as `my_table' and as `MY_TABLE': mysql> SELECT * FROM my_table WHERE MY_TABLE.col=1; Column, index, stored routine, and event names are not case sensitive on any platform, nor are column aliases. However, names of logfile groups are case sensitive. This differs from standard SQL. By default, table aliases are case sensitive on Unix, but not so on Windows or Mac OS X. The following statement would not work on Unix, because it refers to the alias both as `a' and as `A': mysql> SELECT COL_NAME FROM TBL_NAME AS a -> WHERE a.COL_NAME = 1 OR A.COL_NAME = 2; However, this same statement is permitted on Windows. To avoid problems caused by such differences, it is best to adopt a consistent convention, such as always creating and referring to databases and tables using lowercase names. This convention is recommended for maximum portability and ease of use. How table and database names are stored on disk and used in MySQL is affected by the `lower_case_table_names' system variable, which you can set when starting *Note `mysqld': mysqld. `lower_case_table_names' can take the values shown in the following table. This variable does _not_ affect case sensitivity of trigger identifiers. On Unix, the default value of `lower_case_table_names' is 0. On Windows the default value is 1. On Mac OS X, the default value is 2. Value Meaning `0' Table and database names are stored on disk using the lettercase specified in the *Note `CREATE TABLE': create-table. or *Note `CREATE DATABASE': create-database. statement. Name comparisons are case sensitive. You should _not_ set this variable to 0 if you are running MySQL on a system that has case-insensitive file names (such as Windows or Mac OS X). If you force this variable to 0 with `--lower-case-table-names=0' on a case-insensitive file system and access `MyISAM' tablenames using different lettercases, index corruption may result. `1' Table names are stored in lowercase on disk and name comparisons are not case sensitive. MySQL converts all table names to lowercase on storage and lookup. This behavior also applies to database names and table aliases. `2' Table and database names are stored on disk using the lettercase specified in the *Note `CREATE TABLE': create-table. or *Note `CREATE DATABASE': create-database. statement, but MySQL converts them to lowercase on lookup. Name comparisons are not case sensitive. This works _only_ on file systems that are not case sensitive! `InnoDB' table names are stored in lowercase, as for `lower_case_table_names=1'. If you are using MySQL on only one platform, you do not normally have to change the `lower_case_table_names' variable from its default value. However, you may encounter difficulties if you want to transfer tables between platforms that differ in file system case sensitivity. For example, on Unix, you can have two different tables named `my_table' and `MY_TABLE', but on Windows these two names are considered identical. To avoid data transfer problems arising from lettercase of database or table names, you have two options: * Use `lower_case_table_names=1' on all systems. The main disadvantage with this is that when you use *Note `SHOW TABLES': show-tables. or *Note `SHOW DATABASES': show-databases, you do not see the names in their original lettercase. * Use `lower_case_table_names=0' on Unix and `lower_case_table_names=2' on Windows. This preserves the lettercase of database and table names. The disadvantage of this is that you must ensure that your statements always refer to your database and table names with the correct lettercase on Windows. If you transfer your statements to Unix, where lettercase is significant, they do not work if the lettercase is incorrect. *Exception*: If you are using `InnoDB' tables and you are trying to avoid these data transfer problems, you should set `lower_case_table_names' to 1 on all platforms to force names to be converted to lowercase. If you plan to set the `lower_case_table_names' system variable to 1 on Unix, you must first convert your old database and table names to lowercase before stopping *Note `mysqld': mysqld. and restarting it with the new variable setting. Object names may be considered duplicates if their uppercase forms are equal according to a binary collation. That is true for names of cursors, conditions, procedures, functions, savepoints, stored routine parameters, stored program local variables, and plugins. It is not true for names of columns, constraints, databases, partitions, statements prepared with *Note `PREPARE': prepare, tables, triggers, users, and user-defined variables. File system case sensitivity can affect searches in string columns of `INFORMATION_SCHEMA' tables. For more information, see *Note charset-collation-information-schema::.  File: manual.info, Node: identifier-mapping, Next: function-resolution, Prev: identifier-case-sensitivity, Up: identifiers 9.2.3 Mapping of Identifiers to File Names ------------------------------------------ There is a correspondence between database and table identifiers and names in the file system. For the basic structure, MySQL represents each database as a directory in the data directory, and each table by one or more files in the appropriate database directory. For the table format files (`.FRM'), the data is always stored in this structure and location. For the data and index files, the exact representation on disk is storage engine specific. These files may be stored in the same location as the `FRM' files, or the information may be stored separate file. `InnoDB' data is stored in the InnoDB data files. If you are using tablespaces with `InnoDB', then the specific tablespace files you create are used instead. Before MySQL 5.1.6, there are some limitations on the characters that can be used in identifiers for database objects that correspond to file system objects. For example, path name separator characters are not permitted, and ``.'' is not permitted because it begins the extension for table files. As of MySQL 5.1.6, any character is legal in database or table identifiers except ASCII NUL (`0x00'). MySQL encodes any characters that are problematic in the corresponding file system objects when it creates database directories or table files: * Basic Latin letters (`a..zA..Z') and digits (`0..9') are encoded as is. Consequently, their case sensitivity directly depends on file system features. * All other national letters from alphabets that have uppercase/lowercase mapping are encoded as follows: Code range Pattern Number Used Unused Blocks ----------------------------------------------------------------------------- 00C0..017F [@][0..4][g..z] 5*20= 100 97 3 Latin1 Supplement + Ext A 0370..03FF [@][5..9][g..z] 5*20= 100 88 12 Greek + Coptic 0400..052F [@][g..z][0..6] 20*7= 140 137 3 Cyrillic 0530..058F [@][g..z][7..8] 20*2= 40 38 2 Armenian 2160..217F [@][g..z][9] 20*1= 20 16 4 Number Forms 0180..02AF [@][g..z][a..k] 28*11=220 203 17 Latin Ext B + IPA 1E00..1EFF [@][g..z][l..r] 20*7= 140 136 4 Latin Additional Extended 1F00..1FFF [@][g..z][s..z] 20*8= 160 144 16 Greek Extended .... .... [@][a..f][g..z] 6*20= 120 0 120 RESERVED 24B6..24E9 [@][@][a..z] 26 26 0 Enclosed Alphanumerics FF21..FF5A [@][a..z][@] 26 26 0 Full Width forms One of the bytes in the sequence encodes lettercase. For example: `LATIN CAPITAL LETTER A WITH GRAVE' is encoded as `@0G', whereas `LATIN SMALL LETTER A WITH GRAVE' is encoded as `@0g'. Here the third byte (`G' or `g') indicates lettercase. (On a case-insensitive file system, both letters will be treated as the same.) For some blocks, such as Cyrillic, the second byte determines lettercase. For other blocks, such as Latin1 Supplement, the third byte determines lettercase. If two bytes in the sequence are letters (as in Greek Extended), the leftmost letter character stands for lettercase. All other letter bytes must be in lowercase. * All nonletter characters, as well as letters from alphabets that do not have uppercase/lowercase mapping (such as Hebrew) are encoded using hexadecimal representation using lowercase letters for hex digits `a..f': 0x003F -> @003f 0xFFFF -> @ffff The hexadecimal values correspond to character values in the `ucs2' double-byte character set. On Windows, some names such as `nul', `prn', and `aux' cannot be used as file names because they are reserved as device names. As of MySQL 5.1.10, these are permissible names in MySQL. They are encoded by appending `@@@' to the name when the server creates the corresponding file or directory. This occurs on all platforms for portability of the corresponding database object between platforms. If you have databases or tables from a version of MySQL older than 5.1.6 that contain special characters and for which the underlying directory names or file names have not been updated to use the new encoding, the server displays their names with a prefix of `#mysql50#' in the output from `INFORMATION_SCHEMA' tables or *Note `SHOW': show. statements. For example, if you have a table named `a@b' and its name encoding has not been updated, *Note `SHOW TABLES': show-tables. displays it like this: mysql> SHOW TABLES; +----------------+ | Tables_in_test | +----------------+ | #mysql50#a@b | +----------------+ To refer to such a name for which the encoding has not been updated, you must supply the `#mysql50#' prefix: mysql> SHOW COLUMNS FROM `a@b`; ERROR 1146 (42S02): Table 'test.a@b' doesn't exist mysql> SHOW COLUMNS FROM `#mysql50#a@b`; +-------+---------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +-------+---------+------+-----+---------+-------+ | i | int(11) | YES | | NULL | | +-------+---------+------+-----+---------+-------+ To update old names to eliminate the need to use the special prefix to refer to them, re-encode them with *Note `mysqlcheck': mysqlcheck. The following command updates all names to the new encoding: shell> mysqlcheck --check-upgrade --fix-db-names --fix-table-names --all-databases To check only specific databases or tables, omit `--all-databases' and provide the appropriate database or table arguments. For information about *Note `mysqlcheck': mysqlcheck. invocation syntax, see *Note mysqlcheck::. *Note*: The `#mysql50#' prefix is intended only to be used internally by the server. You should not create databases or tables with names that use this prefix. Also, *Note `mysqlcheck': mysqlcheck. cannot fix names that contain literal instances of the `@' character that is used for encoding special characters. If you have databases or tables that contain this character, use *Note `mysqldump': mysqldump. to dump them before upgrading to MySQL 5.1.6 or later, and then reload the dump file after upgrading.  File: manual.info, Node: function-resolution, Prev: identifier-mapping, Up: identifiers 9.2.4 Function Name Parsing and Resolution ------------------------------------------ MySQL 5.1 supports built-in (native) functions, user-defined functions (UDFs), and stored functions. This section describes how the server recognizes whether the name of a built-in function is used as a function call or as an identifier, and how the server determines which function to use in cases when functions of different types exist with a given name. *Built-In Function Name Parsing* The parser uses default rules for parsing names of built-in functions. These rules can be changed by enabling the `IGNORE_SPACE' SQL mode. When the parser encounters a word that is the name of a built-in function, it must determine whether the name signifies a function call or is instead a nonexpression reference to an identifier such as a table or column name. For example, in the following statements, the first reference to `count' is a function call, whereas the second reference is a table name: SELECT COUNT(*) FROM mytable; CREATE TABLE count (i INT); The parser should recognize the name of a built-in function as indicating a function call only when parsing what is expected to be an expression. That is, in nonexpression context, function names are permitted as identifiers. However, some built-in functions have special parsing or implementation considerations, so the parser uses the following rules by default to distinguish whether their names are being used as function calls or as identifiers in nonexpression context: * To use the name as a function call in an expression, there must be no whitespace between the name and the following ``('' parenthesis character. * Conversely, to use the function name as an identifier, it must not be followed immediately by a parenthesis. The requirement that function calls be written with no whitespace between the name and the parenthesis applies only to the built-in functions that have special considerations. `COUNT' is one such name. The exact list of function names for which following whitespace determines their interpretation are those listed in the `sql_functions[]' array of the `sql/lex.h' source file. Before MySQL 5.1, these are rather numerous (about 200), so you may find it easiest to treat the no-whitespace requirement as applying to all function calls. In MySQL 5.1, parser improvements reduce to about 30 the number of affected function names. For functions not listed in the `sql_functions[]') array, whitespace does not matter. They are interpreted as function calls only when used in expression context and may be used freely as identifiers otherwise. `ASCII' is one such name. However, for these nonaffected function names, interpretation may vary in expression context: `FUNC_NAME ()' is interpreted as a built-in function if there is one with the given name; if not, `FUNC_NAME ()' is interpreted as a user-defined function or stored function if one exists with that name. The `IGNORE_SPACE' SQL mode can be used to modify how the parser treats function names that are whitespace-sensitive: * With `IGNORE_SPACE' disabled, the parser interprets the name as a function call when there is no whitespace between the name and the following parenthesis. This occurs even when the function name is used in nonexpression context: mysql> CREATE TABLE count(i INT); ERROR 1064 (42000): You have an error in your SQL syntax ... near 'count(i INT)' To eliminate the error and cause the name to be treated as an identifier, either use whitespace following the name or write it as a quoted identifier (or both): CREATE TABLE count (i INT); CREATE TABLE `count`(i INT); CREATE TABLE `count` (i INT); * With `IGNORE_SPACE' enabled, the parser loosens the requirement that there be no whitespace between the function name and the following parenthesis. This provides more flexibility in writing function calls. For example, either of the following function calls are legal: SELECT COUNT(*) FROM mytable; SELECT COUNT (*) FROM mytable; However, enabling `IGNORE_SPACE' also has the side effect that the parser treats the affected function names as reserved words (see *Note reserved-words::). This means that a space following the name no longer signifies its use as an identifier. The name can be used in function calls with or without following whitespace, but causes a syntax error in nonexpression context unless it is quoted. For example, with `IGNORE_SPACE' enabled, both of the following statements fail with a syntax error because the parser interprets `count' as a reserved word: CREATE TABLE count(i INT); CREATE TABLE count (i INT); To use the function name in nonexpression context, write it as a quoted identifier: CREATE TABLE `count`(i INT); CREATE TABLE `count` (i INT); To enable the `IGNORE_SPACE' SQL mode, use this statement: SET sql_mode = 'IGNORE_SPACE'; `IGNORE_SPACE' is also enabled by certain other composite modes such as `ANSI' that include it in their value: SET sql_mode = 'ANSI'; Check *Note server-sql-mode::, to see which composite modes enable `IGNORE_SPACE'. To minimize the dependency of SQL code on the `IGNORE_SPACE' setting, use these guidelines: * Avoid creating UDFs or stored functions that have the same name as a built-in function. * Avoid using function names in nonexpression context. For example, these statements use `count' (one of the affected function names affected by `IGNORE_SPACE'), so they fail with or without whitespace following the name if `IGNORE_SPACE' is enabled: CREATE TABLE count(i INT); CREATE TABLE count (i INT); If you must use a function name in nonexpression context, write it as a quoted identifier: CREATE TABLE `count`(i INT); CREATE TABLE `count` (i INT); The number of function names affected by `IGNORE_SPACE' was reduced significantly in MySQL 5.1.13, from about 200 to about 30. As of MySQL 5.1.13, only the following functions are still affected by the `IGNORE_SPACE' setting. `ADDDATE' `BIT_AND' `BIT_OR' `BIT_XOR' `CAST' `COUNT' `CURDATE' `CURTIME' `DATE_ADD' `DATE_SUB' `EXTRACT' `GROUP_CONCAT' `MAX' `MID' `MIN' `NOW' `POSITION' `SESSION_USER' `STD' `STDDEV' `STDDEV_POP' `STDDEV_SAMP' `SUBDATE' `SUBSTR' `SUBSTRING' `SUM' `SYSDATE' `SYSTEM_USER' `TRIM' `VARIANCE' `VAR_POP' `VAR_SAMP' For earlier versions of MySQL, check the contents of the `sql_functions[]' array in the `sql/lex.h' source file to see which functions are affected by `IGNORE_SPACE'. *Incompatibility warning*: The change in MySQL 5.1.13 that reduces the number of function names affected by `IGNORE_SPACE' improves the consistency of parser operation. However, it also introduces the possibility of incompatibility for old SQL code that relies on the following conditions: * `IGNORE_SPACE' is disabled. * The presence or absence of whitespace following a function name is used to distinguish between a built-in function and stored function that have the same name, such as `PI()' versus `PI ()'. For functions that are no longer affected by `IGNORE_SPACE' as of MySQL 5.1.13, that strategy no longer works. Either of the following approaches can be used if you have code that is subject to the preceding incompatibility: * If a stored function has a name that conflicts with a built-in function, refer to the stored function with a schema name qualifier, regardless of whether whitespace is present. For example, write `SCHEMA_NAME.PI()' or `SCHEMA_NAME.PI ()'. * Alternatively, rename the stored function to use a nonconflicting name and change invocations of the function to use the new name. *Function Name Resolution* The following rules describe how the server resolves references to function names for function creation and invocation: * Built-in functions and user-defined functions As of MySQL 5.1.14, an error occurs if you try to create a UDF with the same name as a built-in function. Before 5.1.14, a UDF can be created with the same name as a built-in function but the UDF cannot be invoked because the parser resolves invocations of the function to refer to the built-in function. For example, if you create a UDF named `ABS', references to `ABS()' invoke the built-in function. * Built-in functions and stored functions It is possible to create a stored function with the same name as a built-in function, but to invoke the stored function it is necessary to qualify it with a schema name. For example, if you create a stored function named `PI' in the `test' schema, you invoke it as `test.PI()' because the server resolves `PI()' as a reference to the built-in function. As of 5.1.14, the server creates a warning if the stored function name collides with a built-in function name. The warning can be displayed with *Note `SHOW WARNINGS': show-warnings. * User-defined functions and stored functions User-defined functions and stored functions share the same namespace, so you cannot create a UDF and a stored function with the same name. The preceding function name resolution rules have implications for upgrading to versions of MySQL that implement new built-in functions: * If you have already created a user-defined function with a given name and upgrade MySQL to a version that implements a new built-in function with the same name, the UDF becomes inaccessible. To correct this, use *Note `DROP FUNCTION': drop-function. to drop the UDF, and then use *Note `CREATE FUNCTION': create-function. to re-create the UDF with a different nonconflicting name. * If a new version of MySQL implements a built-in function with the same name as an existing stored function, you have two choices: Rename the stored function to use a nonconflicting name, or change calls to the function so that they use a schema qualifier (that is, use `SCHEMA_NAME.FUNC_NAME()' syntax).  File: manual.info, Node: reserved-words, Next: user-variables, Prev: identifiers, Up: language-structure 9.3 Reserved Words ================== Certain words such as *Note `SELECT': select, *Note `DELETE': delete, or *Note `BIGINT': numeric-types. are reserved and require special treatment for use as identifiers such as table and column names. This may also be true for the names of built-in functions. Reserved words are permitted as identifiers if you quote them as described in *Note identifiers::: mysql> CREATE TABLE interval (begin INT, end INT); ERROR 1064 (42000): You have an error in your SQL syntax ... near 'interval (begin INT, end INT)' mysql> CREATE TABLE `interval` (begin INT, end INT); Query OK, 0 rows affected (0.01 sec) Exception: A word that follows a period in a qualified name must be an identifier, so it need not be quoted even if it is reserved: mysql> CREATE TABLE mydb.interval (begin INT, end INT); Query OK, 0 rows affected (0.01 sec) Names of built-in functions are permitted as identifiers but may require care to be used as such. For example, `COUNT' is acceptable as a column name. However, by default, no whitespace is permitted in function invocations between the function name and the following ``('' character. This requirement enables the parser to distinguish whether the name is used in a function call or in nonfunction context. For further detail on recognition of function names, see *Note function-resolution::. The words in the following table are explicitly reserved in MySQL 5.1. In addition, `_FILENAME' is reserved. At some point, you might upgrade to a higher version, so it is a good idea to have a look at future reserved words, too. You can find these in the manuals that cover higher versions of MySQL. Most of the words in the table are forbidden by standard SQL as column or table names (for example, `GROUP'). A few are reserved because MySQL needs them and uses a `yacc' parser. A reserved word can be used as an identifier if you quote it. For a more detailed list of reserved words, including differences between versions, see Reserved Words in MySQL 5.1 (http://dev.mysql.com/doc/mysqld-version-reference/en/mysqld-version-reference-reservedwords.html#mysqld-version-reference-reservedwords-5-1). `ACCESSIBLE' `ADD' `ALL' `ALTER' `ANALYZE' `AND' `AS' `ASC' `ASENSITIVE' `BEFORE' `BETWEEN' `BIGINT' `BINARY' `BLOB' `BOTH' `BY' `CALL' `CASCADE' `CASE' `CHANGE' `CHAR' `CHARACTER' `CHECK' `COLLATE' `COLUMN' `CONDITION' `CONSTRAINT' `CONTINUE' `CONVERT' `CREATE' `CROSS' `CURRENT_DATE' `CURRENT_TIME' `CURRENT_TIMESTAMP' `CURRENT_USER' `CURSOR' `DATABASE' `DATABASES' `DAY_HOUR' `DAY_MICROSECOND' `DAY_MINUTE' `DAY_SECOND' `DEC' `DECIMAL' `DECLARE' `DEFAULT' `DELAYED' `DELETE' `DESC' `DESCRIBE' `DETERMINISTIC' `DISTINCT' `DISTINCTROW' `DIV' `DOUBLE' `DROP' `DUAL' `EACH' `ELSE' `ELSEIF' `ENCLOSED' `ESCAPED' `EXISTS' `EXIT' `EXPLAIN' `FALSE' `FETCH' `FLOAT' `FLOAT4' `FLOAT8' `FOR' `FORCE' `FOREIGN' `FROM' `FULLTEXT' `GRANT' `GROUP' `HAVING' `HIGH_PRIORITY' `HOUR_MICROSECOND' `HOUR_MINUTE' `HOUR_SECOND' `IF' `IGNORE' `IN' `INDEX' `INFILE' `INNER' `INOUT' `INSENSITIVE' `INSERT' `INT' `INT1' `INT2' `INT3' `INT4' `INT8' `INTEGER' `INTERVAL' `INTO' `IS' `ITERATE' `JOIN' `KEY' `KEYS' `KILL' `LEADING' `LEAVE' `LEFT' `LIKE' `LIMIT' `LINEAR' `LINES' `LOAD' `LOCALTIME' `LOCALTIMESTAMP' `LOCK' `LONG' `LONGBLOB' `LONGTEXT' `LOOP' `LOW_PRIORITY' `MASTER_SSL_VERIFY_SERVER_CERT' `MATCH' `MEDIUMBLOB' `MEDIUMINT' `MEDIUMTEXT' `MIDDLEINT' `MINUTE_MICROSECOND' `MINUTE_SECOND' `MOD' `MODIFIES' `NATURAL' `NOT' `NO_WRITE_TO_BINLOG' `NULL' `NUMERIC' `ON' `OPTIMIZE' `OPTION' `OPTIONALLY' `OR' `ORDER' `OUT' `OUTER' `OUTFILE' `PRECISION' `PRIMARY' `PROCEDURE' `PURGE' `RANGE' `READ' `READS' `READ_WRITE' `REAL' `REFERENCES' `REGEXP' `RELEASE' `RENAME' `REPEAT' `REPLACE' `REQUIRE' `RESTRICT' `RETURN' `REVOKE' `RIGHT' `RLIKE' `SCHEMA' `SCHEMAS' `SECOND_MICROSECOND' `SELECT' `SENSITIVE' `SEPARATOR' `SET' `SHOW' `SMALLINT' `SPATIAL' `SPECIFIC' `SQL' `SQLEXCEPTION' `SQLSTATE' `SQLWARNING' `SQL_BIG_RESULT' `SQL_CALC_FOUND_ROWS' `SQL_SMALL_RESULT' `SSL' `STARTING' `STRAIGHT_JOIN' `TABLE' `TERMINATED' `THEN' `TINYBLOB' `TINYINT' `TINYTEXT' `TO' `TRAILING' `TRIGGER' `TRUE' `UNDO' `UNION' `UNIQUE' `UNLOCK' `UNSIGNED' `UPDATE' `USAGE' `USE' `USING' `UTC_DATE' `UTC_TIME' `UTC_TIMESTAMP' `VALUES' `VARBINARY' `VARCHAR' `VARCHARACTER' `VARYING' `WHEN' `WHERE' `WHILE' `WITH' `WRITE' `XOR' `YEAR_MONTH' `ZEROFILL' The following are new reserved words in MySQL 5.1: `ACCESSIBLE' `LINEAR' `MASTER_SSL_VERIFY_SERVER_CERT' `RANGE' `READ_ONLY' `READ_WRITE' MySQL permits some keywords to be used as unquoted identifiers because many people previously used them. Examples are those in the following list: * `ACTION' * *Note `BIT': numeric-types. * *Note `DATE': datetime. * *Note `ENUM': enum. * `NO' * *Note `TEXT': blob. * *Note `TIME': time. * *Note `TIMESTAMP': datetime.  File: manual.info, Node: user-variables, Next: expressions, Prev: reserved-words, Up: language-structure 9.4 User-Defined Variables ========================== You can store a value in a user-defined variable in one statement and then refer to it later in another statement. This enables you to pass values from one statement to another. _User-defined variables are connection-specific_. That is, a user variable defined by one client cannot be seen or used by other clients. All variables for a given client connection are automatically freed when that client exits. User variables are written as `@VAR_NAME', where the variable name VAR_NAME consists of alphanumeric characters, ``.'', ``_'', and ``$''. A user variable name can contain other characters if you quote it as a string or identifier (for example, `@'my-var'', `@"my-var"', or `@`my-var`'). User variable names are not case sensitive in MySQL 5.0 and up. One way to set a user-defined variable is by issuing a *Note `SET': set-option. statement: SET @VAR_NAME = EXPR [, @VAR_NAME = EXPR] ... For *Note `SET': set-option, either `=' or `:=' can be used as the assignment operator. You can also assign a value to a user variable in statements other than *Note `SET': set-option. In this case, the assignment operator must be `:=' and not `=' because the latter is treated as the comparison operator `=' in non-*Note `SET': set-option. statements: mysql> SET @t1=1, @t2=2, @t3:=4; mysql> SELECT @t1, @t2, @t3, @t4 := @t1+@t2+@t3; +------+------+------+--------------------+ | @t1 | @t2 | @t3 | @t4 := @t1+@t2+@t3 | +------+------+------+--------------------+ | 1 | 2 | 4 | 7 | +------+------+------+--------------------+ User variables can be assigned a value from a limited set of data types: integer, decimal, floating-point, binary or nonbinary string, or `NULL' value. Assignment of decimal and real values does not preserve the precision or scale of the value. A value of a type other than one of the permissible types is converted to a permissible type. For example, a value having a temporal or spatial data type is converted to a binary string. If a user variable is assigned a nonbinary (character) string value, it has the same character set and collation as the string. The coercibility of user variables is implicit. (This is the same coercibility as for table column values.) Bit values assigned to user variables are treated as binary strings. To assign a bit value as a number to a user variable, use `CAST()' or `+0': mysql> SET @v1 = b'1000001'; mysql> SET @v2 = CAST(b'1000001' AS UNSIGNED), @v3 = b'1000001'+0; mysql> SELECT @v1, @v2, @v3; +------+------+------+ | @v1 | @v2 | @v3 | +------+------+------+ | A | 65 | 65 | +------+------+------+ If the value of a user variable is selected in a result set, it is returned to the client as a string. If you refer to a variable that has not been initialized, it has a value of `NULL' and a type of string. User variables may be used in most contexts where expressions are permitted. This does not currently include contexts that explicitly require a literal value, such as in the `LIMIT' clause of a *Note `SELECT': select. statement, or the `IGNORE N LINES' clause of a *Note `LOAD DATA': load-data. statement. As a general rule, you should never assign a value to a user variable and read the value within the same statement. You might get the results you expect, but this is not guaranteed. The order of evaluation for expressions involving user variables is undefined and may change based on the elements contained within a given statement. In `SELECT @a, @a:=@a+1, ...', you might think that MySQL will evaluate `@a' first and then do an assignment second. However, changing the statement (for example, by adding a `GROUP BY', `HAVING', or `ORDER BY' clause) may cause MySQL to select an execution plan with a different order of evaluation. Another issue with assigning a value to a variable and reading the value within the same statement is that the default result type of a variable is based on its type at the start of the statement. The following example illustrates this: mysql> SET @a='test'; mysql> SELECT @a,(@a:=20) FROM TBL_NAME; For this *Note `SELECT': select. statement, MySQL reports to the client that column one is a string and converts all accesses of `@a' to strings, even though @a is set to a number for the second row. After the *Note `SELECT': select. statement executes, `@a' is regarded as a number for the next statement. To avoid problems with this behavior, either do not assign a value to and read the value of the same variable within a single statement, or else set the variable to `0', `0.0', or `''' to define its type before you use it. In a *Note `SELECT': select. statement, each select expression is evaluated only when sent to the client. This means that in a `HAVING', `GROUP BY', or `ORDER BY' clause, referring to a variable that is assigned a value in the select expression list does _not_ work as expected: mysql> SELECT (@aa:=id) AS a, (@aa+3) AS b FROM TBL_NAME HAVING b=5; The reference to `b' in the `HAVING' clause refers to an alias for an expression in the select list that uses `@aa'. This does not work as expected: `@aa' contains the value of `id' from the previous selected row, not from the current row. User variables are intended to provide data values. They cannot be used directly in an SQL statement as an identifier or as part of an identifier, such as in contexts where a table or database name is expected, or as a reserved word such as *Note `SELECT': select. This is true even if the variable is quoted, as shown in the following example: mysql> SELECT c1 FROM t; +----+ | c1 | +----+ | 0 | +----+ | 1 | +----+ 2 rows in set (0.00 sec) mysql> SET @col = "c1"; Query OK, 0 rows affected (0.00 sec) mysql> SELECT @col FROM t; +------+ | @col | +------+ | c1 | +------+ 1 row in set (0.00 sec) mysql> SELECT `@col` FROM t; `ERROR 1054 (42S22): Unknown column '@col' in 'field list'' mysql> SET @col = "`c1`"; Query OK, 0 rows affected (0.00 sec) mysql> SELECT @col FROM t; +------+ | @col | +------+ | `c1` | +------+ 1 row in set (0.00 sec) An exception to this principle that user variables cannot be used to provide identifiers is that if you are constructing a string for use as a prepared statement to be executed later. In this case, user variables can be used to provide any part of the statement. The following example illustrates how this can be done: mysql> SET @c = "c1"; Query OK, 0 rows affected (0.00 sec) mysql> SET @s = CONCAT("SELECT ", @c, " FROM t"); Query OK, 0 rows affected (0.00 sec) mysql> PREPARE stmt FROM @s; Query OK, 0 rows affected (0.04 sec) Statement prepared mysql> EXECUTE stmt; +----+ | c1 | +----+ | 0 | +----+ | 1 | +----+ 2 rows in set (0.00 sec) mysql> DEALLOCATE PREPARE stmt; Query OK, 0 rows affected (0.00 sec) See *Note sql-syntax-prepared-statements::, for more information. A similar technique can be used in application programs to construct SQL statements using program variables, as shown here using PHP 5: query($query); while($row = $result->fetch_assoc()) { echo "

" . $row["$col"] . "

\n"; } $result->close(); $mysqli->close(); ?> Assembling an SQL statement in this fashion is sometimes known as `Dynamic SQL'.  File: manual.info, Node: expressions, Next: comments, Prev: user-variables, Up: language-structure 9.5 Expression Syntax ===================== The following rules define expression syntax in MySQL. The grammar shown here is based on that given in the `sql/sql_yacc.yy' file of MySQL source distributions. See the notes after the grammar for additional information about some of the terms. Operator precedence is given in *Note operator-precedence::. EXPR: EXPR OR EXPR | EXPR || EXPR | EXPR XOR EXPR | EXPR AND EXPR | EXPR && EXPR | NOT EXPR | ! EXPR | BOOLEAN_PRIMARY IS [NOT] {TRUE | FALSE | UNKNOWN} | BOOLEAN_PRIMARY BOOLEAN_PRIMARY: BOOLEAN_PRIMARY IS [NOT] NULL | BOOLEAN_PRIMARY <=> PREDICATE | BOOLEAN_PRIMARY COMPARISON_OPERATOR PREDICATE | BOOLEAN_PRIMARY COMPARISON_OPERATOR {ALL | ANY} (SUBQUERY) | PREDICATE COMPARISON_OPERATOR: = | >= | > | <= | < | <> | != PREDICATE: BIT_EXPR [NOT] IN (SUBQUERY) | BIT_EXPR [NOT] IN (EXPR [, EXPR] ...) | BIT_EXPR [NOT] BETWEEN BIT_EXPR AND PREDICATE | BIT_EXPR SOUNDS LIKE BIT_EXPR | BIT_EXPR [NOT] LIKE SIMPLE_EXPR [ESCAPE SIMPLE_EXPR] | BIT_EXPR [NOT] REGEXP BIT_EXPR | BIT_EXPR BIT_EXPR: BIT_EXPR | BIT_EXPR | BIT_EXPR & BIT_EXPR | BIT_EXPR << BIT_EXPR | BIT_EXPR >> BIT_EXPR | BIT_EXPR + BIT_EXPR | BIT_EXPR - BIT_EXPR | BIT_EXPR * BIT_EXPR | BIT_EXPR / BIT_EXPR | BIT_EXPR DIV BIT_EXPR | BIT_EXPR MOD BIT_EXPR | BIT_EXPR % BIT_EXPR | BIT_EXPR ^ BIT_EXPR | BIT_EXPR + INTERVAL_EXPR | BIT_EXPR - INTERVAL_EXPR | SIMPLE_EXPR SIMPLE_EXPR: LITERAL | IDENTIFIER | FUNCTION_CALL | SIMPLE_EXPR COLLATE COLLATION_NAME | PARAM_MARKER | VARIABLE | SIMPLE_EXPR || SIMPLE_EXPR | + SIMPLE_EXPR | - SIMPLE_EXPR | ~ SIMPLE_EXPR | ! SIMPLE_EXPR | BINARY SIMPLE_EXPR | (EXPR [, EXPR] ...) | ROW (EXPR, EXPR [, EXPR] ...) | (SUBQUERY) | EXISTS (SUBQUERY) | {IDENTIFIER EXPR} | MATCH_EXPR | CASE_EXPR | INTERVAL_EXPR Notes: For literal value syntax, see *Note literals::. For identifier syntax, see *Note identifiers::. Variables can be user variables, system variables, or stored program local variables or parameters: * User variables: *Note user-variables:: * System variables: *Note using-system-variables:: * Local variables: *Note declare-local-variable:: * Parameters: *Note create-procedure:: PARAM_MARKER is `'?'' as used in prepared statements for placeholders. See *Note prepare::. `(SUBQUERY)' indicates a subquery that returns a single value; that is, a scalar subquery. See *Note scalar-subqueries::. `{IDENTIFIER EXPR}' is ODBC escape syntax and is accepted for ODBC compatibility. The value is EXPR. The curly braces in the syntax should be written literally; they are not metasyntax as used elsewhere in syntax descriptions. MATCH_EXPR indicates a `MATCH' expression. See *Note fulltext-search::. CASE_EXPR indicates a `CASE' expression. See *Note control-flow-functions::. INTERVAL_EXPR represents a time interval. The syntax is `INTERVAL EXPR UNIT', where UNIT is a specifier such as `HOUR', `DAY', or `WEEK'. For the full list of UNIT specifiers, see the description of the `DATE_ADD()' function in *Note date-and-time-functions::. The meaning of some operators depends on the SQL mode: * By default, `||' is a logical `OR' operator. With `PIPES_AS_CONCAT' enabled, `||' is string concatenation, with a precedence between `^' and the unary operators. * By default, `!' has a higher precedence than `NOT'. With `HIGH_NOT_PRECEDENCE' enabled, `!' and `NOT' have the same precedence. See *Note server-sql-mode::.  File: manual.info, Node: comments, Prev: expressions, Up: language-structure 9.6 Comment Syntax ================== MySQL Server supports three comment styles: * From a ``#'' character to the end of the line. * From a ``-- '' sequence to the end of the line. In MySQL, the ``-- '' (double-dash) comment style requires the second dash to be followed by at least one whitespace or control character (such as a space, tab, newline, and so on). This syntax differs slightly from standard SQL comment syntax, as discussed in *Note ansi-diff-comments::. * From a `/*' sequence to the following `*/' sequence, as in the C programming language. This syntax enables a comment to extend over multiple lines because the beginning and closing sequences need not be on the same line. The following example demonstrates all three comment styles: mysql> SELECT 1+1; # This comment continues to the end of line mysql> SELECT 1+1; -- This comment continues to the end of line mysql> SELECT 1 /* this is an in-line comment */ + 1; mysql> SELECT 1+ /* this is a multiple-line comment */ 1; Nested comments are not supported. (Under some conditions, nested comments might be permitted, but usually are not, and users should avoid them.) MySQL Server supports some variants of C-style comments. These enable you to write code that includes MySQL extensions, but is still portable, by using comments of the following form: /*! MYSQL-SPECIFIC CODE */ In this case, MySQL Server parses and executes the code within the comment as it would any other SQL statement, but other SQL servers will ignore the extensions. For example, MySQL Server recognizes the `STRAIGHT_JOIN' keyword in the following statement, but other servers will not: SELECT /*! STRAIGHT_JOIN */ col1 FROM table1,table2 WHERE ... If you add a version number after the ``!'' character, the syntax within the comment is executed only if the MySQL version is greater than or equal to the specified version number. The `TEMPORARY' keyword in the following comment is executed only by servers from MySQL 3.23.02 or higher: CREATE /*!32302 TEMPORARY */ TABLE t (a INT); The comment syntax just described applies to how the *Note `mysqld': mysqld. server parses SQL statements. The *Note `mysql': mysql. client program also performs some parsing of statements before sending them to the server. (It does this to determine statement boundaries within a multiple-statement input line.) Comments in this format, `/*!12345 ... */', are not stored on the server. If this format is used to comment stored routines, the comments will not be retained on the server. The use of short-form *Note `mysql': mysql. commands such as `\C' within multi-line `/* ... */' comments is not supported.  File: manual.info, Node: globalization, Next: data-types, Prev: language-structure, Up: Top 10 Globalization **************** * Menu: * charset:: Character Set Support * error-message-language:: Setting the Error Message Language * adding-character-set:: Adding a Character Set * adding-collation:: Adding a Collation to a Character Set * charset-configuration:: Character Set Configuration * time-zone-support:: MySQL Server Time Zone Support * locale-support:: MySQL Server Locale Support This chapter covers issues of globalization, which includes internationalization (MySQL's capabilities for adapting to local use) and localization (selecting particular local conventions): * MySQL support for character sets in SQL statements. * How to configure the server to support different character sets. * Selecting the language for error messages. * How to set the server's time zone and enable per-connection time zone support. * Selecting the locale for day and month names.  File: manual.info, Node: charset, Next: error-message-language, Prev: globalization, Up: globalization 10.1 Character Set Support ========================== * Menu: * charset-general:: Character Sets and Collations in General * charset-mysql:: Character Sets and Collations in MySQL * charset-syntax:: Specifying Character Sets and Collations * charset-connection:: Connection Character Sets and Collations * charset-applications:: Configuring the Character Set and Collation for Applications * charset-errors:: Character Set for Error Messages * charset-collations:: Collation Issues * charset-repertoire:: String Repertoire * charset-operations:: Operations Affected by Character Set Support * charset-unicode:: Unicode Support * charset-metadata:: UTF-8 for Metadata * charset-conversion:: Column Character Set Conversion * charset-charsets:: Character Sets and Collations That MySQL Supports MySQL includes character set support that enables you to store data using a variety of character sets and perform comparisons according to a variety of collations. You can specify character sets at the server, database, table, and column level. MySQL supports the use of character sets for the `MyISAM', `MEMORY', *Note `NDBCLUSTER': mysql-cluster, and `InnoDB' storage engines. This chapter discusses the following topics: * What are character sets and collations? * The multiple-level default system for character set assignment * Syntax for specifying character sets and collations * Affected functions and operations * Unicode support * The character sets and collations that are available, with notes Character set issues affect not only data storage, but also communication between client programs and the MySQL server. If you want the client program to communicate with the server using a character set different from the default, you'll need to indicate which one. For example, to use the `utf8' Unicode character set, issue this statement after connecting to the server: SET NAMES 'utf8'; For more information about configuring character sets for application use and character set-related issues in client/server communication, see *Note charset-applications::, and *Note charset-connection::.  File: manual.info, Node: charset-general, Next: charset-mysql, Prev: charset, Up: charset 10.1.1 Character Sets and Collations in General ----------------------------------------------- A _character set_ is a set of symbols and encodings. A _collation_ is a set of rules for comparing characters in a character set. Let's make the distinction clear with an example of an imaginary character set. Suppose that we have an alphabet with four letters: ``A'', ``B'', ``a'', ``b''. We give each letter a number: ``A'' = 0, ``B'' = 1, ``a'' = 2, ``b'' = 3. The letter ``A'' is a symbol, the number 0 is the *encoding* for ``A'', and the combination of all four letters and their encodings is a *character set*. Suppose that we want to compare two string values, ``A'' and ``B''. The simplest way to do this is to look at the encodings: 0 for ``A'' and 1 for ``B''. Because 0 is less than 1, we say ``A'' is less than ``B''. What we've just done is apply a collation to our character set. The collation is a set of rules (only one rule in this case): `compare the encodings.' We call this simplest of all possible collations a _binary_ collation. But what if we want to say that the lowercase and uppercase letters are equivalent? Then we would have at least two rules: (1) treat the lowercase letters ``a'' and ``b'' as equivalent to ``A'' and ``B''; (2) then compare the encodings. We call this a _case-insensitive_ collation. It is a little more complex than a binary collation. In real life, most character sets have many characters: not just ``A'' and ``B'' but whole alphabets, sometimes multiple alphabets or eastern writing systems with thousands of characters, along with many special symbols and punctuation marks. Also in real life, most collations have many rules, not just for whether to distinguish lettercase, but also for whether to distinguish accents (an `accent' is a mark attached to a character as in German ``O"''), and for multiple-character mappings (such as the rule that ``O"'' = ``OE'' in one of the two German collations). MySQL can do these things for you: * Store strings using a variety of character sets * Compare strings using a variety of collations * Mix strings with different character sets or collations in the same server, the same database, or even the same table * Enable specification of character set and collation at any level In these respects, MySQL is far ahead of most other database management systems. However, to use these features effectively, you need to know what character sets and collations are available, how to change the defaults, and how they affect the behavior of string operators and functions.  File: manual.info, Node: charset-mysql, Next: charset-syntax, Prev: charset-general, Up: charset 10.1.2 Character Sets and Collations in MySQL --------------------------------------------- The MySQL server can support multiple character sets. To list the available character sets, use the *Note `SHOW CHARACTER SET': show-character-set. statement. A partial listing follows. For more complete information, see *Note charset-charsets::. mysql> SHOW CHARACTER SET; +----------+-----------------------------+---------------------+--------+ | Charset | Description | Default collation | Maxlen | +----------+-----------------------------+---------------------+--------+ | big5 | Big5 Traditional Chinese | big5_chinese_ci | 2 | | dec8 | DEC West European | dec8_swedish_ci | 1 | | cp850 | DOS West European | cp850_general_ci | 1 | | hp8 | HP West European | hp8_english_ci | 1 | | koi8r | KOI8-R Relcom Russian | koi8r_general_ci | 1 | | latin1 | cp1252 West European | latin1_swedish_ci | 1 | | latin2 | ISO 8859-2 Central European | latin2_general_ci | 1 | | swe7 | 7bit Swedish | swe7_swedish_ci | 1 | | ascii | US ASCII | ascii_general_ci | 1 | | ujis | EUC-JP Japanese | ujis_japanese_ci | 3 | | sjis | Shift-JIS Japanese | sjis_japanese_ci | 2 | | hebrew | ISO 8859-8 Hebrew | hebrew_general_ci | 1 | | tis620 | TIS620 Thai | tis620_thai_ci | 1 | | euckr | EUC-KR Korean | euckr_korean_ci | 2 | | koi8u | KOI8-U Ukrainian | koi8u_general_ci | 1 | | gb2312 | GB2312 Simplified Chinese | gb2312_chinese_ci | 2 | | greek | ISO 8859-7 Greek | greek_general_ci | 1 | | cp1250 | Windows Central European | cp1250_general_ci | 1 | | gbk | GBK Simplified Chinese | gbk_chinese_ci | 2 | | latin5 | ISO 8859-9 Turkish | latin5_turkish_ci | 1 | ... Any given character set always has at least one collation. It may have several collations. To list the collations for a character set, use the *Note `SHOW COLLATION': show-collation. statement. For example, to see the collations for the `latin1' (cp1252 West European) character set, use this statement to find those collation names that begin with `latin1': mysql> SHOW COLLATION LIKE 'latin1%'; +---------------------+---------+----+---------+----------+---------+ | Collation | Charset | Id | Default | Compiled | Sortlen | +---------------------+---------+----+---------+----------+---------+ | latin1_german1_ci | latin1 | 5 | | | 0 | | latin1_swedish_ci | latin1 | 8 | Yes | Yes | 1 | | latin1_danish_ci | latin1 | 15 | | | 0 | | latin1_german2_ci | latin1 | 31 | | Yes | 2 | | latin1_bin | latin1 | 47 | | Yes | 1 | | latin1_general_ci | latin1 | 48 | | | 0 | | latin1_general_cs | latin1 | 49 | | | 0 | | latin1_spanish_ci | latin1 | 94 | | | 0 | +---------------------+---------+----+---------+----------+---------+ The `latin1' collations have the following meanings. Collation Meaning `latin1_german1_ci' German DIN-1 `latin1_swedish_ci' Swedish/Finnish `latin1_danish_ci' Danish/Norwegian `latin1_german2_ci' German DIN-2 `latin1_bin' Binary according to `latin1' encoding `latin1_general_ci' Multilingual (Western European) `latin1_general_cs' Multilingual (ISO Western European), case sensitive `latin1_spanish_ci' Modern Spanish Collations have these general characteristics: * Two different character sets cannot have the same collation. * Each character set has one collation that is the _default collation_. For example, the default collation for `latin1' is `latin1_swedish_ci'. The output for *Note `SHOW CHARACTER SET': show-character-set. indicates which collation is the default for each displayed character set. * There is a convention for collation names: They start with the name of the character set with which they are associated, they usually include a language name, and they end with `_ci' (case insensitive), `_cs' (case sensitive), or `_bin' (binary). In cases where a character set has multiple collations, it might not be clear which collation is most suitable for a given application. To avoid choosing the wrong collation, it can be helpful to perform some comparisons with representative data values to make sure that a given collation sorts values the way you expect. Collation-Charts.Org (http://www.collation-charts.org/) is a useful site for information that shows how one collation compares to another.  File: manual.info, Node: charset-syntax, Next: charset-connection, Prev: charset-mysql, Up: charset 10.1.3 Specifying Character Sets and Collations ----------------------------------------------- * Menu: * charset-server:: Server Character Set and Collation * charset-database:: Database Character Set and Collation * charset-table:: Table Character Set and Collation * charset-column:: Column Character Set and Collation * charset-literal:: Character String Literal Character Set and Collation * charset-national:: National Character Set * charset-examples:: Examples of Character Set and Collation Assignment * charset-compatibility:: Compatibility with Other DBMSs There are default settings for character sets and collations at four levels: server, database, table, and column. The description in the following sections may appear complex, but it has been found in practice that multiple-level defaulting leads to natural and obvious results. `CHARACTER SET' is used in clauses that specify a character set. `CHARSET' can be used as a synonym for `CHARACTER SET'. Character set issues affect not only data storage, but also communication between client programs and the MySQL server. If you want the client program to communicate with the server using a character set different from the default, you'll need to indicate which one. For example, to use the `utf8' Unicode character set, issue this statement after connecting to the server: SET NAMES 'utf8'; For more information about character set-related issues in client/server communication, see *Note charset-connection::.  File: manual.info, Node: charset-server, Next: charset-database, Prev: charset-syntax, Up: charset-syntax 10.1.3.1 Server Character Set and Collation ........................................... MySQL Server has a server character set and a server collation. These can be set at server startup on the command line or in an option file and changed at runtime. Initially, the server character set and collation depend on the options that you use when you start *Note `mysqld': mysqld. You can use `--character-set-server' for the character set. Along with it, you can add `--collation-server' for the collation. If you don't specify a character set, that is the same as saying `--character-set-server=latin1'. If you specify only a character set (for example, `latin1') but not a collation, that is the same as saying `--character-set-server=latin1' `--collation-server=latin1_swedish_ci' because `latin1_swedish_ci' is the default collation for `latin1'. Therefore, the following three commands all have the same effect: shell> mysqld shell> mysqld --character-set-server=latin1 shell> mysqld --character-set-server=latin1 \ --collation-server=latin1_swedish_ci One way to change the settings is by recompiling. If you want to change the default server character set and collation when building from sources, use: `--with-charset' and `--with-collation' as arguments for `configure'. For example: shell> ./configure --with-charset=latin1 Or: shell> ./configure --with-charset=latin1 \ --with-collation=latin1_german1_ci Both *Note `mysqld': mysqld. and `configure' verify that the character set/collation combination is valid. If not, each program displays an error message and terminates. The server character set and collation are used as default values if the database character set and collation are not specified in *Note `CREATE DATABASE': create-database. statements. They have no other purpose. The current server character set and collation can be determined from the values of the `character_set_server' and `collation_server' system variables. These variables can be changed at runtime.  File: manual.info, Node: charset-database, Next: charset-table, Prev: charset-server, Up: charset-syntax 10.1.3.2 Database Character Set and Collation ............................................. Every database has a database character set and a database collation. The *Note `CREATE DATABASE': create-database. and *Note `ALTER DATABASE': alter-database. statements have optional clauses for specifying the database character set and collation: CREATE DATABASE DB_NAME [[DEFAULT] CHARACTER SET CHARSET_NAME] [[DEFAULT] COLLATE COLLATION_NAME] ALTER DATABASE DB_NAME [[DEFAULT] CHARACTER SET CHARSET_NAME] [[DEFAULT] COLLATE COLLATION_NAME] The keyword `SCHEMA' can be used instead of `DATABASE'. All database options are stored in a text file named `db.opt' that can be found in the database directory. The `CHARACTER SET' and `COLLATE' clauses make it possible to create databases with different character sets and collations on the same MySQL server. Example: CREATE DATABASE DB_NAME CHARACTER SET latin1 COLLATE latin1_swedish_ci; MySQL chooses the database character set and database collation in the following manner: * If both `CHARACTER SET X' and `COLLATE Y' are specified, character set X and collation Y are used. * If `CHARACTER SET X' is specified without `COLLATE', character set X and its default collation are used. To see the default collation for each character set, use the *Note `SHOW COLLATION': show-collation. statement. * If `COLLATE Y' is specified without `CHARACTER SET', the character set associated with Y and collation Y are used. * Otherwise, the server character set and server collation are used. The database character set and collation are used as default values for table definitions if the table character set and collation are not specified in *Note `CREATE TABLE': create-table. statements. The database character set also is used by *Note `LOAD DATA INFILE': load-data. The character set and collation have no other purposes. The character set and collation for the default database can be determined from the values of the `character_set_database' and `collation_database' system variables. The server sets these variables whenever the default database changes. If there is no default database, the variables have the same value as the corresponding server-level system variables, `character_set_server' and `collation_server'.  File: manual.info, Node: charset-table, Next: charset-column, Prev: charset-database, Up: charset-syntax 10.1.3.3 Table Character Set and Collation .......................................... Every table has a table character set and a table collation. The *Note `CREATE TABLE': create-table. and *Note `ALTER TABLE': alter-table. statements have optional clauses for specifying the table character set and collation: CREATE TABLE TBL_NAME (COLUMN_LIST) [[DEFAULT] CHARACTER SET CHARSET_NAME] [COLLATE COLLATION_NAME]] ALTER TABLE TBL_NAME [[DEFAULT] CHARACTER SET CHARSET_NAME] [COLLATE COLLATION_NAME] Example: CREATE TABLE t1 ( ... ) CHARACTER SET latin1 COLLATE latin1_danish_ci; MySQL chooses the table character set and collation in the following manner: * If both `CHARACTER SET X' and `COLLATE Y' are specified, character set X and collation Y are used. * If `CHARACTER SET X' is specified without `COLLATE', character set X and its default collation are used. To see the default collation for each character set, use the *Note `SHOW COLLATION': show-collation. statement. * If `COLLATE Y' is specified without `CHARACTER SET', the character set associated with Y and collation Y are used. * Otherwise, the database character set and collation are used. The table character set and collation are used as default values for column definitions if the column character set and collation are not specified in individual column definitions. The table character set and collation are MySQL extensions; there are no such things in standard SQL.  File: manual.info, Node: charset-column, Next: charset-literal, Prev: charset-table, Up: charset-syntax 10.1.3.4 Column Character Set and Collation ........................................... Every `character' column (that is, a column of type *Note `CHAR': char, *Note `VARCHAR': char, or *Note `TEXT': blob.) has a column character set and a column collation. Column definition syntax for *Note `CREATE TABLE': create-table. and *Note `ALTER TABLE': alter-table. has optional clauses for specifying the column character set and collation: COL_NAME {CHAR | VARCHAR | TEXT} (COL_LENGTH) [CHARACTER SET CHARSET_NAME] [COLLATE COLLATION_NAME] These clauses can also be used for *Note `ENUM': enum. and *Note `SET': set. columns: COL_NAME {ENUM | SET} (VAL_LIST) [CHARACTER SET CHARSET_NAME] [COLLATE COLLATION_NAME] Examples: CREATE TABLE t1 ( col1 VARCHAR(5) CHARACTER SET latin1 COLLATE latin1_german1_ci ); ALTER TABLE t1 MODIFY col1 VARCHAR(5) CHARACTER SET latin1 COLLATE latin1_swedish_ci; MySQL chooses the column character set and collation in the following manner: * If both `CHARACTER SET X' and `COLLATE Y' are specified, character set X and collation Y are used. CREATE TABLE t1 ( col1 CHAR(10) CHARACTER SET utf8 COLLATE utf8_unicode_ci ) CHARACTER SET latin1 COLLATE latin1_bin; The character set and collation are specified for the column, so they are used. The column has character set `utf8' and collation `utf8_unicode_ci'. * If `CHARACTER SET X' is specified without `COLLATE', character set X and its default collation are used. CREATE TABLE t1 ( col1 CHAR(10) CHARACTER SET utf8 ) CHARACTER SET latin1 COLLATE latin1_bin; The character set is specified for the column, but the collation is not. The column has character set `utf8' and the default collation for `utf8', which is `utf8_general_ci'. To see the default collation for each character set, use the *Note `SHOW COLLATION': show-collation. statement. * If `COLLATE Y' is specified without `CHARACTER SET', the character set associated with Y and collation Y are used. CREATE TABLE t1 ( col1 CHAR(10) COLLATE utf8_polish_ci ) CHARACTER SET latin1 COLLATE latin1_bin; The collation is specified for the column, but the character set is not. The column has collation `utf8_polish_ci' and the character set is the one associated with the collation, which is `utf8'. * Otherwise, the table character set and collation are used. CREATE TABLE t1 ( col1 CHAR(10) ) CHARACTER SET latin1 COLLATE latin1_bin; Neither the character set nor collation are specified for the column, so the table defaults are used. The column has character set `latin1' and collation `latin1_bin'. The `CHARACTER SET' and `COLLATE' clauses are standard SQL. If you use *Note `ALTER TABLE': alter-table. to convert a column from one character set to another, MySQL attempts to map the data values, but if the character sets are incompatible, there may be data loss.  File: manual.info, Node: charset-literal, Next: charset-national, Prev: charset-column, Up: charset-syntax 10.1.3.5 Character String Literal Character Set and Collation ............................................................. Every character string literal has a character set and a collation. A character string literal may have an optional character set introducer and `COLLATE' clause: [_CHARSET_NAME]'STRING' [COLLATE COLLATION_NAME] Examples: SELECT 'STRING'; SELECT _latin1'STRING'; SELECT _latin1'STRING' COLLATE latin1_danish_ci; For the simple statement `SELECT 'STRING'', the string has the character set and collation defined by the `character_set_connection' and `collation_connection' system variables. The `_CHARSET_NAME' expression is formally called an _introducer_. It tells the parser, `the string that is about to follow uses character set X.' Because this has confused people in the past, we emphasize that an introducer does not change the string to the introducer character set like `CONVERT()' would do. It does not change the string's value, although padding may occur. The introducer is just a signal. An introducer is also legal before standard hex literal and numeric hex literal notation (`x'LITERAL'' and `0xNNNN'), or before bit-field literal notation (`b'LITERAL'' and `0bNNNN'). Examples: SELECT _latin1 x'AABBCC'; SELECT _latin1 0xAABBCC; SELECT _latin1 b'1100011'; SELECT _latin1 0b1100011; MySQL determines a literal's character set and collation in the following manner: * If both _X and `COLLATE Y' are specified, character set X and collation Y are used. * If _X is specified but `COLLATE' is not specified, character set X and its default collation are used. To see the default collation for each character set, use the *Note `SHOW COLLATION': show-collation. statement. * Otherwise, the character set and collation given by the `character_set_connection' and `collation_connection' system variables are used. Examples: * A string with `latin1' character set and `latin1_german1_ci' collation: SELECT _latin1'Mu"ller' COLLATE latin1_german1_ci; * A string with `latin1' character set and its default collation (that is, `latin1_swedish_ci'): SELECT _latin1'Mu"ller'; * A string with the connection default character set and collation: SELECT 'Mu"ller'; Character set introducers and the `COLLATE' clause are implemented according to standard SQL specifications. An introducer indicates the character set for the following string, but does not change now how the parser performs escape processing within the string. Escapes are always interpreted by the parser according to the character set given by `character_set_connection'. The following examples show that escape processing occurs using `character_set_connection' even in the presence of an introducer. The examples use `SET NAMES' (which changes `character_set_connection', as discussed in *Note charset-connection::), and display the resulting strings using the `HEX()' function so that the exact string contents can be seen. Example 1: mysql> SET NAMES latin1; Query OK, 0 rows affected (0.01 sec) mysql> SELECT HEX('a`\n'), HEX(_sjis'a`\n'); +------------+-----------------+ | HEX('a`\n') | HEX(_sjis'a`\n') | +------------+-----------------+ | E00A | E00A | +------------+-----------------+ 1 row in set (0.00 sec) Here, ``a`'' (hex value `E0') is followed by ``\n'', the escape sequence for newline. The escape sequence is interpreted using the `character_set_connection' value of `latin1' to produce a literal newline (hex value `0A'). This happens even for the second string. That is, the introducer of `_sjis' does not affect the parser's escape processing. Example 2: mysql> SET NAMES sjis; Query OK, 0 rows affected (0.00 sec) mysql> SELECT HEX('a`\n'), HEX(_latin1'a`\n'); +------------+-------------------+ | HEX('a`\n') | HEX(_latin1'a`\n') | +------------+-------------------+ | E05C6E | E05C6E | +------------+-------------------+ 1 row in set (0.04 sec) Here, `character_set_connection' is `sjis', a character set in which the sequence of ``a`'' followed by ``\'' (hex values `05' and `5C') is a valid multi-byte character. Hence, the first two bytes of the string are interpreted as a single `sjis' character, and the ``\'' is not interpreted as an escape character. The following ``n'' (hex value `6E') is not interpreted as part of an escape sequence. This is true even for the second string; the introducer of `_latin1' does not affect escape processing.  File: manual.info, Node: charset-national, Next: charset-examples, Prev: charset-literal, Up: charset-syntax 10.1.3.6 National Character Set ............................... Standard SQL defines *Note `NCHAR': char. or *Note `NATIONAL CHAR': char. as a way to indicate that a *Note `CHAR': char. column should use some predefined character set. MySQL 5.1 uses `utf8' as this predefined character set. For example, these data type declarations are equivalent: CHAR(10) CHARACTER SET utf8 NATIONAL CHARACTER(10) NCHAR(10) As are these: VARCHAR(10) CHARACTER SET utf8 NATIONAL VARCHAR(10) NCHAR VARCHAR(10) NATIONAL CHARACTER VARYING(10) NATIONAL CHAR VARYING(10) You can use `N'LITERAL'' (or `n'LITERAL'') to create a string in the national character set. These statements are equivalent: SELECT N'some text'; SELECT n'some text'; SELECT _utf8'some text'; For information on upgrading character sets to MySQL 5.1 from versions prior to 4.1, see the `MySQL 3.23, 4.0, 4.1 Reference Manual'.  File: manual.info, Node: charset-examples, Next: charset-compatibility, Prev: charset-national, Up: charset-syntax 10.1.3.7 Examples of Character Set and Collation Assignment ........................................................... The following examples show how MySQL determines default character set and collation values. *Example 1: Table and Column Definition* CREATE TABLE t1 ( c1 CHAR(10) CHARACTER SET latin1 COLLATE latin1_german1_ci ) DEFAULT CHARACTER SET latin2 COLLATE latin2_bin; Here we have a column with a `latin1' character set and a `latin1_german1_ci' collation. The definition is explicit, so that is straightforward. Notice that there is no problem with storing a `latin1' column in a `latin2' table. *Example 2: Table and Column Definition* CREATE TABLE t1 ( c1 CHAR(10) CHARACTER SET latin1 ) DEFAULT CHARACTER SET latin1 COLLATE latin1_danish_ci; This time we have a column with a `latin1' character set and a default collation. Although it might seem natural, the default collation is not taken from the table level. Instead, because the default collation for `latin1' is always `latin1_swedish_ci', column `c1' has a collation of `latin1_swedish_ci' (not `latin1_danish_ci'). *Example 3: Table and Column Definition* CREATE TABLE t1 ( c1 CHAR(10) ) DEFAULT CHARACTER SET latin1 COLLATE latin1_danish_ci; We have a column with a default character set and a default collation. In this circumstance, MySQL checks the table level to determine the column character set and collation. Consequently, the character set for column `c1' is `latin1' and its collation is `latin1_danish_ci'. *Example 4: Database, Table, and Column Definition* CREATE DATABASE d1 DEFAULT CHARACTER SET latin2 COLLATE latin2_czech_ci; USE d1; CREATE TABLE t1 ( c1 CHAR(10) ); We create a column without specifying its character set and collation. We're also not specifying a character set and a collation at the table level. In this circumstance, MySQL checks the database level to determine the table settings, which thereafter become the column settings.) Consequently, the character set for column `c1' is `latin2' and its collation is `latin2_czech_ci'.  File: manual.info, Node: charset-compatibility, Prev: charset-examples, Up: charset-syntax 10.1.3.8 Compatibility with Other DBMSs ....................................... For MaxDB compatibility these two statements are the same: CREATE TABLE t1 (f1 CHAR(N) UNICODE); CREATE TABLE t1 (f1 CHAR(N) CHARACTER SET ucs2);  File: manual.info, Node: charset-connection, Next: charset-applications, Prev: charset-syntax, Up: charset 10.1.4 Connection Character Sets and Collations ----------------------------------------------- Several character set and collation system variables relate to a client's interaction with the server. Some of these have been mentioned in earlier sections: * The server character set and collation are the values of the `character_set_server' and `collation_server' system variables. * The character set and collation of the default database are the values of the `character_set_database' and `collation_database' system variables. Additional character set and collation system variables are involved in handling traffic for the connection between a client and the server. Every client has connection-related character set and collation system variables. A `connection' is what you make when you connect to the server. The client sends SQL statements, such as queries, over the connection to the server. The server sends responses, such as result sets or error messages, over the connection back to the client. This leads to several questions about character set and collation handling for client connections, each of which can be answered in terms of system variables: * What character set is the statement in when it leaves the client? The server takes the `character_set_client' system variable to be the character set in which statements are sent by the client. * What character set should the server translate a statement to after receiving it? For this, the server uses the `character_set_connection' and `collation_connection' system variables. It converts statements sent by the client from `character_set_client' to `character_set_connection' (except for string literals that have an introducer such as `_latin1' or `_utf8'). `collation_connection' is important for comparisons of literal strings. For comparisons of strings with column values, `collation_connection' does not matter because columns have their own collation, which has a higher collation precedence. * What character set should the server translate to before shipping result sets back to the client? The `character_set_results' system variable indicates the character set in which the server returns query results to the client. This includes result data such as column values, and result metadata such as column names. Clients can fine-tune the settings for these variables, or depend on the defaults (in which case, you can skip the rest of this section). If you do not use the defaults, you must change the character settings _for each connection to the server._ Two statements affect the connection-related character set variables as a group: * `SET NAMES 'CHARSET_NAME' [COLLATE 'COLLATION_NAME']' `SET NAMES' indicates what character set the client will use to send SQL statements to the server. Thus, `SET NAMES 'cp1251'' tells the server, `future incoming messages from this client are in character set `cp1251'.' It also specifies the character set that the server should use for sending results back to the client. (For example, it indicates what character set to use for column values if you use a *Note `SELECT': select. statement.) A `SET NAMES 'X'' statement is equivalent to these three statements: SET character_set_client = X; SET character_set_results = X; SET character_set_connection = X; Setting `character_set_connection' to X also implicitly sets `collation_connection' to the default collation for X. It is unnecessary to set that collation explicitly. To specify a particular collation, use the optional `COLLATE' clause: SET NAMES 'CHARSET_NAME' COLLATE 'COLLATION_NAME' * `SET CHARACTER SET CHARSET_NAME' `SET CHARACTER SET' is similar to `SET NAMES' but sets `character_set_connection' and `collation_connection' to `character_set_database' and `collation_database'. A `SET CHARACTER SET X' statement is equivalent to these three statements: SET character_set_client = X; SET character_set_results = X; SET collation_connection = @@collation_database; Setting `collation_connection' also implicitly sets `character_set_connection' to the character set associated with the collation (equivalent to executing `SET character_set_connection = @@character_set_database'). It is unnecessary to set `character_set_connection' explicitly. *Note*: `ucs2' cannot be used as a client character set, which means that it does not work for `SET NAMES' or `SET CHARACTER SET'. The MySQL client programs `mysql', `mysqladmin', `mysqlcheck', `mysqlimport', and `mysqlshow' determine the default character set to use as follows: * In the absence of other information, the programs use the compiled-in default character set, usually `latin1'. * The programs support a `--default-character-set' option, which enables users to specify the character set explicitly to override whatever default the client otherwise determines. When a client connects to the server, it sends the name of the character set that it wants to use. The server uses the name to set the `character_set_client', `character_set_results', and `character_set_connection' system variables. In effect, the server performs a `SET NAMES' operation using the character set name. With the *Note `mysql': mysql. client, if you want to use a character set different from the default, you could explicitly execute `SET NAMES' every time you start up. However, to accomplish the same result more easily, you can add the `--default-character-set' option setting to your *Note `mysql': mysql. command line or in your option file. For example, the following option file setting changes the three connection-related character set variables set to `koi8r' each time you invoke *Note `mysql': mysql.: [mysql] default-character-set=koi8r If you are using the *Note `mysql': mysql. client with auto-reconnect enabled (which is not recommended), it is preferable to use the `charset' command rather than `SET NAMES'. For example: mysql> charset utf8 Charset changed The `charset' command issues a `SET NAMES' statement, and also changes the default character set that *Note `mysql': mysql. uses when it reconnects after the connection has dropped. Example: Suppose that `column1' is defined as `CHAR(5) CHARACTER SET latin2'. If you do not say `SET NAMES' or `SET CHARACTER SET', then for `SELECT column1 FROM t', the server sends back all the values for `column1' using the character set that the client specified when it connected. On the other hand, if you say `SET NAMES 'latin1'' or `SET CHARACTER SET latin1' before issuing the *Note `SELECT': select. statement, the server converts the `latin2' values to `latin1' just before sending results back. Conversion may be lossy if there are characters that are not in both character sets. If you do not want the server to perform any conversion of result sets or error messages, set `character_set_results' to `NULL' or `binary': SET character_set_results = NULL; To see the values of the character set and collation system variables that apply to your connection, use these statements: SHOW VARIABLES LIKE 'character_set%'; SHOW VARIABLES LIKE 'collation%'; You must also consider the environment within which your MySQL applications execute. See *Note charset-applications::. For more information about character sets and error messages, see *Note charset-errors::.  File: manual.info, Node: charset-applications, Next: charset-errors, Prev: charset-connection, Up: charset 10.1.5 Configuring the Character Set and Collation for Applications ------------------------------------------------------------------- For applications that store data using the default MySQL character set and collation (`latin1', `latin1_swedish_ci'), no special configuration should be needed. If applications require data storage using a different character set or collation, you can configure character set information several ways: * Specify character settings per database. For example, applications that use one database might require `utf8', whereas applications that use another database might require `sjis'. * Specify character settings at server startup. This causes the server to use the given settings for all applications that do not make other arrangements. * Specify character settings at configuration time, if you build MySQL from source. This causes the server to use the given settings for all applications, without having to specify them at server startup. When different applications require different character settings, the per-database technique provides a good deal of flexibility. If most or all applications use the same character set, specifying character settings at server startup or configuration time may be most convenient. For the per-database or server-startup techniques, the settings control the character set for data storage. Applications must also tell the server which character set to use for client/server communications, as described in the following instructions. The examples shown here assume use of the `utf8' character set and `utf8_general_ci' collation. *Specify character settings per database.* To create a database such that its tables will use a given default character set and collation for data storage, use a *Note `CREATE DATABASE': create-database. statement like this: CREATE DATABASE mydb DEFAULT CHARACTER SET utf8 DEFAULT COLLATE utf8_general_ci; Tables created in the database will use `utf8' and `utf8_general_ci' by default for any character columns. Applications that use the database should also configure their connection to the server each time they connect. This can be done by executing a `SET NAMES 'utf8'' statement after connecting. The statement can be used regardless of connection method: The *Note `mysql': mysql. client, PHP scripts, and so forth. In some cases, it may be possible to configure the connection to use the desired character set some other way. For example, for connections made using *Note `mysql': mysql, you can specify the `--default-character-set=utf8' command-line option to achieve the same effect as `SET NAMES 'utf8''. For more information about configuring client connections, see *Note charset-connection::. *Specify character settings at server startup.* To select a character set and collation at server startup, use the `--character-set-server' and `--collation-server' options. For example, to specify the options in an option file, include these lines: [mysqld] character-set-server=utf8 collation-server=utf8_general_ci These settings apply server-wide and apply as the defaults for databases created by any application, and for tables created in those databases. It is still necessary for applications to configure their connection using `SET NAMES' or equivalent after they connect, as described previously. You might be tempted to start the server with the `--init_connect="SET NAMES 'utf8'"' option to cause `SET NAMES' to be executed automatically for each client that connects. However, this will yield inconsistent results because the `init_connect' value is not executed for users who have the `SUPER' privilege. *Specify character settings at MySQL configuration time.* To select a character set and collation when you configure and build MySQL from source, use the `--with-charset' and `--with-collation' options: shell> ./configure --with-charset=utf8 --with-collation=utf8_general_ci The resulting server uses `utf8' and `utf8_general_ci' as the default for databases and tables and for client connections. It is unnecessary to use `--character-set-server' and `--collation-server' to specify those defaults at server startup. It is also unnecessary for applications to configure their connection using `SET NAMES' or equivalent after they connect to the server. Regardless of how you configure the MySQL character set for application use, you must also consider the environment within which those applications execute. If you will send statements using UTF-8 text taken from a file that you create in an editor, you should edit the file with the locale of your environment set to UTF-8 so that the file encoding is correct and so that the operating system handles it correctly. If you use the *Note `mysql': mysql. client from within a terminal window, the window must be configured to use UTF-8 or characters may not display properly. For a script that executes in a Web environment, the script must handle character encoding properly for its interaction with the MySQL server, and it must generate pages that correctly indicate the encoding so that browsers know how to display the content of the pages. For example, you can include this `' tag within your `' element:  File: manual.info, Node: charset-errors, Next: charset-collations, Prev: charset-applications, Up: charset 10.1.6 Character Set for Error Messages --------------------------------------- This section describes how the server uses character sets for constructing error messages and returning them to clients. For information about the language of error messages (rather than the character set), see *Note error-message-language::. In MySQL 5.1, the server constructs error messages and returns them to clients as follows: * The message template has the character set associated with the error message language. For example, English, Korean, and Russian messages use `latin1', `euckr', and `koi8r', respectively. * Parameters in the message template are replaced with values that apply to a specific error occurrence. These parameters use their own character set. Identifiers such as table or column names use UTF-8. Data values retain their character set. For example, in the following duplicate-key message, `'XXX'' has the character set of the table column associated with key 1: Duplicate entry 'XXX' for key1 The preceding method of error-message construction can result in messages that contain a mix of character sets unless all items involved contain only ASCII characters. This issue is resolved in MySQL 5.5, in which error messages are constructed internally within the server using UTF-8 and returned to the client in the character set specified by the `character_set_results' system variable.  File: manual.info, Node: charset-collations, Next: charset-repertoire, Prev: charset-errors, Up: charset 10.1.7 Collation Issues ----------------------- * Menu: * charset-collation-names:: Collation Names * charset-collate:: Using `COLLATE' in SQL Statements * charset-collate-precedence:: `COLLATE' Clause Precedence * charset-collation-charset:: Collations Must Be for the Right Character Set * charset-collation-expressions:: Collation of Expressions * charset-binary-collations:: The `_bin' and `binary' Collations * charset-binary-op:: The `BINARY' Operator * charset-collation-effect:: Examples of the Effect of Collation * charset-collation-information-schema:: Collation and `INFORMATION_SCHEMA' Searches The following sections discuss various aspects of character set collations.  File: manual.info, Node: charset-collation-names, Next: charset-collate, Prev: charset-collations, Up: charset-collations 10.1.7.1 Collation Names ........................ MySQL collation names follow these rules: * A name ending in `_ci' indicates a case-insensitive collation. * A name ending in `_cs' indicates a case-sensitive collation. * A name ending in `_bin' indicates a binary collation. Character comparisons are based on character binary code values.  File: manual.info, Node: charset-collate, Next: charset-collate-precedence, Prev: charset-collation-names, Up: charset-collations 10.1.7.2 Using `COLLATE' in SQL Statements .......................................... With the `COLLATE' clause, you can override whatever the default collation is for a comparison. `COLLATE' may be used in various parts of SQL statements. Here are some examples: * With `ORDER BY': SELECT k FROM t1 ORDER BY k COLLATE latin1_german2_ci; * With `AS': SELECT k COLLATE latin1_german2_ci AS k1 FROM t1 ORDER BY k1; * With `GROUP BY': SELECT k FROM t1 GROUP BY k COLLATE latin1_german2_ci; * With aggregate functions: SELECT MAX(k COLLATE latin1_german2_ci) FROM t1; * With `DISTINCT': SELECT DISTINCT k COLLATE latin1_german2_ci FROM t1; * With `WHERE': SELECT * FROM t1 WHERE _latin1 'Mu"ller' COLLATE latin1_german2_ci = k; SELECT * FROM t1 WHERE k LIKE _latin1 'Mu"ller' COLLATE latin1_german2_ci; * With `HAVING': SELECT k FROM t1 GROUP BY k HAVING k = _latin1 'Mu"ller' COLLATE latin1_german2_ci;  File: manual.info, Node: charset-collate-precedence, Next: charset-collation-charset, Prev: charset-collate, Up: charset-collations 10.1.7.3 `COLLATE' Clause Precedence .................................... The `COLLATE' clause has high precedence (higher than `||'), so the following two expressions are equivalent: x || y COLLATE z x || (y COLLATE z)  File: manual.info, Node: charset-collation-charset, Next: charset-collation-expressions, Prev: charset-collate-precedence, Up: charset-collations 10.1.7.4 Collations Must Be for the Right Character Set ....................................................... Each character set has one or more collations, but each collation is associated with one and only one character set. Therefore, the following statement causes an error message because the `latin2_bin' collation is not legal with the `latin1' character set: mysql> SELECT _latin1 'x' COLLATE latin2_bin; ERROR 1253 (42000): COLLATION 'latin2_bin' is not valid for CHARACTER SET 'latin1'  File: manual.info, Node: charset-collation-expressions, Next: charset-binary-collations, Prev: charset-collation-charset, Up: charset-collations 10.1.7.5 Collation of Expressions ................................. In the great majority of statements, it is obvious what collation MySQL uses to resolve a comparison operation. For example, in the following cases, it should be clear that the collation is the collation of column `x': SELECT x FROM T ORDER BY x; SELECT x FROM T WHERE x = x; SELECT DISTINCT x FROM T; However, with multiple operands, there can be ambiguity. For example: SELECT x FROM T WHERE x = 'Y'; Should the comparison use the collation of the column `x', or of the string literal `'Y''? Both `x' and `'Y'' have collations, so which collation takes precedence? Standard SQL resolves such questions using what used to be called `coercibility' rules. MySQL assigns coercibility values as follows: * An explicit `COLLATE' clause has a coercibility of 0. (Not coercible at all.) * The concatenation of two strings with different collations has a coercibility of 1. * The collation of a column or a stored routine parameter or local variable has a coercibility of 2. * A `system constant' (the string returned by functions such as `USER()' or `VERSION()') has a coercibility of 3. * The collation of a literal has a coercibility of 4. * `NULL' or an expression that is derived from `NULL' has a coercibility of 5. MySQL uses coercibility values with the following rules to resolve ambiguities: * Use the collation with the lowest coercibility value. * If both sides have the same coercibility, then: * If both sides are Unicode, or both sides are not Unicode, it is an error. * If one of the sides has a Unicode character set, and another side has a non-Unicode character set, the side with Unicode character set wins, and automatic character set conversion is applied to the non-Unicode side. For example, the following statement does not return an error: SELECT CONCAT(utf8_column, latin1_column) FROM t1; It returns a result that has a character set of `utf8' and the same collation as `utf8_column'. Values of `latin1_column' are automatically converted to `utf8' before concatenating. * For an operation with operands from the same character set but that mix a `_bin' collation and a `_ci' or `_cs' collation, the `_bin' collation is used. This is similar to how operations that mix nonbinary and binary strings evaluate the operands as binary strings, except that it is for collations rather than data types. Although automatic conversion is not in the SQL standard, the SQL standard document does say that every character set is (in terms of supported characters) a `subset' of Unicode. Because it is a well-known principle that `what applies to a superset can apply to a subset,' we believe that a collation for Unicode can apply for comparisons with non-Unicode strings. Examples: Comparison Collation Used `column1 = 'A'' Use collation of `column1' `column1 = 'A' COLLATE x' Use collation of `'A' COLLATE x' `column1 COLLATE x = 'A' COLLATE y' Error The `COERCIBILITY()' function can be used to determine the coercibility of a string expression: mysql> SELECT COERCIBILITY('A' COLLATE latin1_swedish_ci); -> 0 mysql> SELECT COERCIBILITY(VERSION()); -> 3 mysql> SELECT COERCIBILITY('A'); -> 4 See *Note information-functions::. For implicit conversion of a numeric or temporal value to a string, such as occurs for the argument `1' in the expression `CONCAT(1, 'abc')', the result is a binary string for which the character set and collation are `binary'. See *Note type-conversion::.  File: manual.info, Node: charset-binary-collations, Next: charset-binary-op, Prev: charset-collation-expressions, Up: charset-collations 10.1.7.6 The `_bin' and `binary' Collations ........................................... This section describes how `_bin' collations for nonbinary strings differ from the `binary' `collation' for binary strings. Nonbinary strings (as stored in the *Note `CHAR': char, *Note `VARCHAR': char, and *Note `TEXT': blob. data types) have a character set and collation. A given character set can have several collations, each of which defines a particular sorting and comparison order for the characters in the set. One of these is the binary collation for the character set, indicated by a `_bin' suffix in the collation name. For example, `latin1' and `utf8' have binary collations named `latin1_bin' and `utf8_bin'. Binary strings (as stored in the *Note `BINARY': binary-varbinary, *Note `VARBINARY': binary-varbinary, and *Note `BLOB': blob. data types) have no character set or collation in the sense that nonbinary strings do. (Applied to a binary string, the `CHARSET()' and `COLLATION()' functions both return a value of `binary'.) Binary strings are sequences of bytes and the numeric values of those bytes determine sort order. The `_bin' collations differ from the `binary' collation in several respects. *The unit for sorting and comparison.* Binary strings are sequences of bytes. Sorting and comparison is always based on numeric byte values. Nonbinary strings are sequences of characters, which might be multi-byte. Collations for nonbinary strings define an ordering of the character values for sorting and comparison. For the `_bin' collation, this ordering is based solely on binary code values of the characters (which is similar to ordering for binary strings except that a `_bin' collation must take into account that a character might contain multiple bytes). For other collations, character ordering might take additional factors such as lettercase into account. *Character set conversion.* A nonbinary string has a character set and is converted to another character set in many cases, even when the string has a `_bin' collation: * When assigning column values from another column that has a different character set: UPDATE t1 SET utf8_bin_column=latin1_column; INSERT INTO t1 (latin1_column) SELECT utf8_bin_column FROM t2; * When assigning column values for *Note `INSERT': insert. or *Note `UPDATE': update. using a string literal: SET NAMES latin1; INSERT INTO t1 (utf8_bin_column) VALUES ('string-in-latin1'); * When sending results from the server to a client: SET NAMES latin1; SELECT utf8_bin_column FROM t2; For binary string columns, no conversion occurs. For the preceding cases, the string value is copied byte-wise. *Lettercase conversion.* Collations provide information about lettercase of characters, so characters in a nonbinary string can be converted from one lettercase to another, even for `_bin' collations that ignore lettercase for ordering: mysql> SET NAMES latin1 COLLATE latin1_bin; Query OK, 0 rows affected (0.02 sec) mysql> SELECT LOWER('aA'), UPPER('zZ'); +-------------+-------------+ | LOWER('aA') | UPPER('zZ') | +-------------+-------------+ | aa | ZZ | +-------------+-------------+ 1 row in set (0.13 sec) The concept of lettercase does not apply to bytes in a binary string. To perform lettercase conversion, the string must be converted to a nonbinary string: mysql> SET NAMES binary; Query OK, 0 rows affected (0.00 sec) mysql> SELECT LOWER('aA'), LOWER(CONVERT('aA' USING latin1)); +-------------+-----------------------------------+ | LOWER('aA') | LOWER(CONVERT('aA' USING latin1)) | +-------------+-----------------------------------+ | aA | aa | +-------------+-----------------------------------+ 1 row in set (0.00 sec) *Trailing space handling in comparisons.* Nonbinary strings have `PADSPACE' behavior for all collations, including `_bin' collations. Trailing spaces are insignificant in comparisons: mysql> SET NAMES utf8 COLLATE utf8_bin; Query OK, 0 rows affected (0.00 sec) mysql> SELECT 'a ' = 'a'; +------------+ | 'a ' = 'a' | +------------+ | 1 | +------------+ 1 row in set (0.00 sec) For binary strings, all characters are significant in comparisons, including trailing spaces: mysql> SET NAMES binary; Query OK, 0 rows affected (0.00 sec) mysql> SELECT 'a ' = 'a'; +------------+ | 'a ' = 'a' | +------------+ | 0 | +------------+ 1 row in set (0.00 sec) *Trailing space handling for inserts and retrievals.* `CHAR(N)' columns store nonbinary strings. Values shorter than N characters are extended with spaces on insertion. For retrieval, trailing spaces are removed. `BINARY(N)' columns store binary strings. Values shorter than N bytes are extended with `0x00' bytes on insertion. For retrieval, nothing is removed; a value of the declared length is always returned. mysql> CREATE TABLE t1 ( -> a CHAR(10) CHARACTER SET utf8 COLLATE utf8_bin, -> b BINARY(10) -> ); Query OK, 0 rows affected (0.09 sec) mysql> INSERT INTO t1 VALUES ('a','a'); Query OK, 1 row affected (0.01 sec) mysql> SELECT HEX(a), HEX(b) FROM t1; +--------+----------------------+ | HEX(a) | HEX(b) | +--------+----------------------+ | 61 | 61000000000000000000 | +--------+----------------------+ 1 row in set (0.04 sec)  File: manual.info, Node: charset-binary-op, Next: charset-collation-effect, Prev: charset-binary-collations, Up: charset-collations 10.1.7.7 The `BINARY' Operator .............................. The `BINARY' operator casts the string following it to a binary string. This is an easy way to force a comparison to be done byte by byte rather than character by character. `BINARY' also causes trailing spaces to be significant. mysql> SELECT 'a' = 'A'; -> 1 mysql> SELECT BINARY 'a' = 'A'; -> 0 mysql> SELECT 'a' = 'a '; -> 1 mysql> SELECT BINARY 'a' = 'a '; -> 0 `BINARY STR' is shorthand for `CAST(STR AS BINARY)'. The `BINARY' attribute in character column definitions has a different effect. A character column defined with the `BINARY' attribute is assigned the binary collation of the column character set. Every character set has a binary collation. For example, the binary collation for the `latin1' character set is `latin1_bin', so if the table default character set is `latin1', these two column definitions are equivalent: CHAR(10) BINARY CHAR(10) CHARACTER SET latin1 COLLATE latin1_bin The effect of `BINARY' as a column attribute differs from its effect prior to MySQL 4.1. Formerly, `BINARY' resulted in a column that was treated as a binary string. A binary string is a string of bytes that has no character set or collation, which differs from a nonbinary character string that has a binary collation. For both types of strings, comparisons are based on the numeric values of the string unit, but for nonbinary strings the unit is the character and some character sets support multi-byte characters. *Note binary-varbinary::. The use of `CHARACTER SET binary' in the definition of a *Note `CHAR': char, *Note `VARCHAR': char, or *Note `TEXT': blob. column causes the column to be treated as a binary data type. For example, the following pairs of definitions are equivalent: CHAR(10) CHARACTER SET binary BINARY(10) VARCHAR(10) CHARACTER SET binary VARBINARY(10) TEXT CHARACTER SET binary BLOB  File: manual.info, Node: charset-collation-effect, Next: charset-collation-information-schema, Prev: charset-binary-op, Up: charset-collations 10.1.7.8 Examples of the Effect of Collation ............................................ *Example 1: Sorting German Umlauts* Suppose that column `X' in table `T' has these `latin1' column values: Muffler Mu"ller MX Systems MySQL Suppose also that the column values are retrieved using the following statement: SELECT X FROM T ORDER BY X COLLATE COLLATION_NAME; The following table shows the resulting order of the values if we use `ORDER BY' with different collations. `latin1_swedish_ci' `latin1_german1_ci' `latin1_german2_ci' Muffler Muffler Mu"ller MX Systems Mu"ller Muffler Mu"ller MX Systems MX Systems MySQL MySQL MySQL The character that causes the different sort orders in this example is the U with two dots over it (`u"'), which the Germans call `U-umlaut.' * The first column shows the result of the *Note `SELECT': select. using the Swedish/Finnish collating rule, which says that U-umlaut sorts with Y. * The second column shows the result of the *Note `SELECT': select. using the German DIN-1 rule, which says that U-umlaut sorts with U. * The third column shows the result of the *Note `SELECT': select. using the German DIN-2 rule, which says that U-umlaut sorts with UE. *Example 2: Searching for German Umlauts* Suppose that you have three tables that differ only by the character set and collation used: mysql> SET NAMES utf8; mysql> CREATE TABLE german1 ( -> c CHAR(10) -> ) CHARACTER SET latin1 COLLATE latin1_german1_ci; mysql> CREATE TABLE german2 ( -> c CHAR(10) -> ) CHARACTER SET latin1 COLLATE latin1_german2_ci; mysql> CREATE TABLE germanutf8 ( -> c CHAR(10) -> ) CHARACTER SET utf8 COLLATE utf8_unicode_ci; Each table contains two records: mysql> INSERT INTO german1 VALUES ('Bar'), ('Ba"r'); mysql> INSERT INTO german2 VALUES ('Bar'), ('Ba"r'); mysql> INSERT INTO germanutf8 VALUES ('Bar'), ('Ba"r'); Two of the above collations have an `A = A"' equality, and one has no such equality (`latin1_german2_ci'). For that reason, you'll get these results in comparisons: mysql> SELECT * FROM german1 WHERE c = 'Ba"r'; +------+ | c | +------+ | Bar | | Ba"r | +------+ mysql> SELECT * FROM german2 WHERE c = 'Ba"r'; +------+ | c | +------+ | Ba"r | +------+ mysql> SELECT * FROM germanutf8 WHERE c = 'Ba"r'; +------+ | c | +------+ | Bar | | Ba"r | +------+ This is not a bug but rather a consequence of the sorting properties of `latin1_german1_ci' and `utf8_unicode_ci' (the sorting shown is done according to the German DIN 5007 standard).  File: manual.info, Node: charset-collation-information-schema, Prev: charset-collation-effect, Up: charset-collations 10.1.7.9 Collation and `INFORMATION_SCHEMA' Searches .................................................... String columns in `INFORMATION_SCHEMA' tables have a collation of `utf8_general_ci', which is case insensitive. However, searches in `INFORMATION_SCHEMA' string columns are also affected by file system case sensitivity. For values that correspond to objects that are represented in the file system, such as names of databases and tables, searches may be case sensitive if the file system is case sensitive. This section describes how to work around this issue if necessary; see also Bug#34921. Suppose that a query searches the `SCHEMATA.SCHEMA_NAME' column for the `test' database. On Linux, file systems are case sensitive, so comparisons of `SCHEMATA.SCHEMA_NAME' with `'test'' match, but comparisons with `'TEST'' do not: mysql> SELECT SCHEMA_NAME FROM INFORMATION_SCHEMA.SCHEMATA -> WHERE SCHEMA_NAME = 'test'; +-------------+ | SCHEMA_NAME | +-------------+ | test | +-------------+ 1 row in set (0.01 sec) mysql> SELECT SCHEMA_NAME FROM INFORMATION_SCHEMA.SCHEMATA -> WHERE SCHEMA_NAME = 'TEST'; Empty set (0.00 sec) On Windows or Mac OS X where file systems are not case sensitive, comparisons match both `'test'' and `'TEST'': mysql> SELECT SCHEMA_NAME FROM INFORMATION_SCHEMA.SCHEMATA -> WHERE SCHEMA_NAME = 'test'; +-------------+ | SCHEMA_NAME | +-------------+ | test | +-------------+ 1 row in set (0.00 sec) mysql> SELECT SCHEMA_NAME FROM INFORMATION_SCHEMA.SCHEMATA -> WHERE SCHEMA_NAME = 'TEST'; +-------------+ | SCHEMA_NAME | +-------------+ | TEST | +-------------+ 1 row in set (0.00 sec) The value of the `lower_case_table_names' system variable makes no difference in this context. This behavior occurs because the `utf8_general_ci' collation is not used for `INFORMATION_SCHEMA' queries when searching the file system for database objects. It is a result of optimizations implemented for `INFORMATION_SCHEMA' searches in MySQL 5.1.21 and thus does not occur prior to 5.1.21. For information about these optimizations, see *Note information-schema-optimization::. Searches in `INFORMATION_SCHEMA' string columns for values that refer to `INFORMATION_SCHEMA' itself do use the `utf8_general_ci' collation because `INFORMATION_SCHEMA' is a `virtual' database and is not represented in the file system. For example, comparisons with `SCHEMATA.SCHEMA_NAME' match `'information_schema'' or `'INFORMATION_SCHEMA'' regardless of platform: mysql> SELECT SCHEMA_NAME FROM INFORMATION_SCHEMA.SCHEMATA -> WHERE SCHEMA_NAME = 'information_schema'; +--------------------+ | SCHEMA_NAME | +--------------------+ | information_schema | +--------------------+ 1 row in set (0.00 sec) mysql> SELECT SCHEMA_NAME FROM INFORMATION_SCHEMA.SCHEMATA -> WHERE SCHEMA_NAME = 'INFORMATION_SCHEMA'; +--------------------+ | SCHEMA_NAME | +--------------------+ | information_schema | +--------------------+ 1 row in set (0.00 sec) If the result of a string operation on an `INFORMATION_SCHEMA' column differs from expectations, a workaround is to use an explicit `COLLATE' clause to force a suitable collation (*Note charset-collate::). For example, to perform a case-insensitive search, use `COLLATE' with the `INFORMATION_SCHEMA' column name: mysql> SELECT SCHEMA_NAME FROM INFORMATION_SCHEMA.SCHEMATA -> WHERE SCHEMA_NAME COLLATE utf8_general_ci = 'test'; +-------------+ | SCHEMA_NAME | +-------------+ | test | +-------------+ 1 row in set (0.00 sec) mysql> SELECT SCHEMA_NAME FROM INFORMATION_SCHEMA.SCHEMATA -> WHERE SCHEMA_NAME COLLATE utf8_general_ci = 'TEST'; | SCHEMA_NAME | +-------------+ | test | +-------------+ 1 row in set (0.00 sec) You can also use the `UPPER()' or `LOWER()' function: WHERE UPPER(SCHEMA_NAME) = 'TEST' WHERE LOWER(SCHEMA_NAME) = 'test' Although a case-insensitive comparison can be performed even on platforms with case-sensitive file systems, as just shown, it is not necessarily always the right thing to do. On such platforms, it is possible to have multiple objects with names that differ only in lettercase. For example, tables named `city', `CITY', and `City' can all exist simultaneously. Consider whether a search should match all such names or just one and write queries accordingly: WHERE TABLE_NAME COLLATE utf8_bin = 'City' WHERE TABLE_NAME COLLATE utf8_general_ci = 'city' WHERE UPPER(TABLE_NAME) = 'CITY' WHERE LOWER(TABLE_NAME) = 'city' The first of those comparisons (with `utf8_bin') is case sensitive; the others are not.  File: manual.info, Node: charset-repertoire, Next: charset-operations, Prev: charset-collations, Up: charset 10.1.8 String Repertoire ------------------------ The _repertoire_ of a character set is the collection of characters in the set. As of MySQL 5.1.21, string expressions have a repertoire attribute, which can have two values: * `ASCII': The expression can contain only characters in the Unicode range `U+0000' to `U+007F'. * `UNICODE': The expression can contain characters in the Unicode range `U+0000' to `U+FFFF'. The `ASCII' range is a subset of `UNICODE' range, so a string with `ASCII' repertoire can be converted safely without loss of information to the character set of any string with `UNICODE' repertoire or to a character set that is a superset of `ASCII'. (All MySQL character sets are supersets of `ASCII' with the exception of `swe7', which reuses some punctuation characters for Swedish accented characters.) The use of repertoire enables character set conversion in expressions for many cases where MySQL would otherwise return an `illegal mix of collations' error. The following discussion provides examples of expressions and their repertoires, and describes how the use of repertoire changes string expression evaluation: * The repertoire for string constants depends on string content: SET NAMES utf8; SELECT 'abc'; SELECT _utf8'def'; SELECT N'MySQL'; Although the character set is `utf8' in each of the preceding cases, the strings do not actually contain any characters outside the ASCII range, so their repertoire is `ASCII' rather than `UNICODE'. * Columns having the `ascii' character set have `ASCII' repertoire because of their character set. In the following table, `c1' has `ASCII' repertoire: CREATE TABLE t1 (c1 CHAR(1) CHARACTER SET ascii); The following example illustrates how repertoire enables a result to be determined in a case where an error occurs without repertoire: CREATE TABLE t1 ( c1 CHAR(1) CHARACTER SET latin1, c2 CHAR(1) CHARACTER SET ascii ); INSERT INTO t1 VALUES ('a','b'); SELECT CONCAT(c1,c2) FROM t1; Without repertoire, this error occurs: ERROR 1267 (HY000): Illegal mix of collations (latin1_swedish_ci,IMPLICIT) and (ascii_general_ci,IMPLICIT) for operation 'concat' Using repertoire, subset to superset (`ascii' to `latin1') conversion can occur and a result is returned: +---------------+ | CONCAT(c1,c2) | +---------------+ | ab | +---------------+ * Functions with one string argument inherit the repertoire of their argument. The result of `UPPER(_utf8'ABC')' has `ASCII' repertoire, because its argument has `ASCII' repertoire. * For functions that return a string but do not have string arguments and use `character_set_connection' as the result character set, the result repertoire is `ASCII' if `character_set_connection' is `ascii', and `UNICODE' otherwise: FORMAT(NUMERIC_COLUMN, 4); Use of repertoire changes how MySQL evaluates the following example: SET NAMES ascii; CREATE TABLE t1 (a INT, b VARCHAR(10) CHARACTER SET latin1); INSERT INTO t1 VALUES (1,'b'); SELECT CONCAT(FORMAT(a, 4), b) FROM t1; Without repertoire, this error occurs: ERROR 1267 (HY000): Illegal mix of collations (ascii_general_ci,COERCIBLE) and (latin1_swedish_ci,IMPLICIT) for operation 'concat' With repertoire, a result is returned: +-------------------------+ | CONCAT(FORMAT(a, 4), b) | +-------------------------+ | 1.0000b | +-------------------------+ * Functions with two or more string arguments use the `widest' argument repertoire for the result repertoire (`UNICODE' is wider than `ASCII'). Consider the following `CONCAT()' calls: CONCAT(_ucs2 0x0041, _ucs2 0x0042) CONCAT(_ucs2 0x0041, _ucs2 0x00C2) For the first call, the repertoire is `ASCII' because both arguments are within the range of the `ascii' character set. For the second call, the repertoire is `UNICODE' because the second argument is outside the `ascii' character set range. * The repertoire for function return values is determined based only on the repertoire of the arguments that affect the result's character set and collation. IF(column1 < column2, 'smaller', 'greater') The result repertoire is `ASCII' because the two string arguments (the second argument and the third argument) both have `ASCII' repertoire. The first argument does not matter for the result repertoire, even if the expression uses string values.  File: manual.info, Node: charset-operations, Next: charset-unicode, Prev: charset-repertoire, Up: charset 10.1.9 Operations Affected by Character Set Support --------------------------------------------------- * Menu: * charset-result:: Result Strings * charset-convert:: `CONVERT()' and `CAST()' * charset-show:: `SHOW' Statements and `INFORMATION_SCHEMA' This section describes operations that take character set information into account.  File: manual.info, Node: charset-result, Next: charset-convert, Prev: charset-operations, Up: charset-operations 10.1.9.1 Result Strings ....................... MySQL has many operators and functions that return a string. This section answers the question: What is the character set and collation of such a string? For simple functions that take string input and return a string result as output, the output's character set and collation are the same as those of the principal input value. For example, `UPPER(X)' returns a string whose character string and collation are the same as that of X. The same applies for `INSTR()', `LCASE()', `LOWER()', `LTRIM()', `MID()', `REPEAT()', `REPLACE()', `REVERSE()', `RIGHT()', `RPAD()', `RTRIM()', `SOUNDEX()', `SUBSTRING()', `TRIM()', `UCASE()', and `UPPER()'. Note: The `REPLACE()' function, unlike all other functions, always ignores the collation of the string input and performs a case-sensitive comparison. If a string input or function result is a binary string, the string has no character set or collation. This can be checked by using the `CHARSET()' and `COLLATION()' functions, both of which return `binary' to indicate that their argument is a binary string: mysql> SELECT CHARSET(BINARY 'a'), COLLATION(BINARY 'a'); +---------------------+-----------------------+ | CHARSET(BINARY 'a') | COLLATION(BINARY 'a') | +---------------------+-----------------------+ | binary | binary | +---------------------+-----------------------+ For operations that combine multiple string inputs and return a single string output, the `aggregation rules' of standard SQL apply for determining the collation of the result: * If an explicit `COLLATE X' occurs, use X. * If explicit `COLLATE X' and `COLLATE Y' occur, raise an error. * Otherwise, if all collations are X, use X. * Otherwise, the result has no collation. For example, with `CASE ... WHEN a THEN b WHEN b THEN c COLLATE X END', the resulting collation is X. The same applies for *Note `UNION': union, `||', `CONCAT()', `ELT()', `GREATEST()', `IF()', and `LEAST()'. For operations that convert to character data, the character set and collation of the strings that result from the operations are defined by the `character_set_connection' and `collation_connection' system variables. This applies only to `CAST()', `CONV()', `FORMAT()', `HEX()', and `SPACE()'. If you are uncertain about the character set or collation of the result returned by a string function, you can use the `CHARSET()' or `COLLATION()' function to find out: mysql> SELECT USER(), CHARSET(USER()), COLLATION(USER()); +----------------+-----------------+-------------------+ | USER() | CHARSET(USER()) | COLLATION(USER()) | +----------------+-----------------+-------------------+ | test@localhost | utf8 | utf8_general_ci | +----------------+-----------------+-------------------+  File: manual.info, Node: charset-convert, Next: charset-show, Prev: charset-result, Up: charset-operations 10.1.9.2 `CONVERT()' and `CAST()' ................................. `CONVERT()' provides a way to convert data between different character sets. The syntax is: CONVERT(EXPR USING TRANSCODING_NAME) In MySQL, transcoding names are the same as the corresponding character set names. Examples: SELECT CONVERT(_latin1'Mu"ller' USING utf8); INSERT INTO utf8table (utf8column) SELECT CONVERT(latin1field USING utf8) FROM latin1table; `CONVERT(... USING ...)' is implemented according to the standard SQL specification. You may also use `CAST()' to convert a string to a different character set. The syntax is: CAST(CHARACTER_STRING AS CHARACTER_DATA_TYPE CHARACTER SET CHARSET_NAME) Example: SELECT CAST(_latin1'test' AS CHAR CHARACTER SET utf8); If you use `CAST()' without specifying `CHARACTER SET', the resulting character set and collation are defined by the `character_set_connection' and `collation_connection' system variables. If you use `CAST()' with `CHARACTER SET X', the resulting character set and collation are `X' and the default collation of `X'. You may not use a `COLLATE' clause inside a `CONVERT()' or `CAST()' call, but you may use it outside. For example, `CAST(... COLLATE ...)' is illegal, but `CAST(...) COLLATE ...' is legal: SELECT CAST(_latin1'test' AS CHAR CHARACTER SET utf8) COLLATE utf8_bin;  File: manual.info, Node: charset-show, Prev: charset-convert, Up: charset-operations 10.1.9.3 `SHOW' Statements and `INFORMATION_SCHEMA' ................................................... Several *Note `SHOW': show. statements provide additional character set information. These include *Note `SHOW CHARACTER SET': show-character-set, *Note `SHOW COLLATION': show-collation, *Note `SHOW CREATE DATABASE': show-create-database, *Note `SHOW CREATE TABLE': show-create-table. and *Note `SHOW COLUMNS': show-columns. These statements are described here briefly. For more information, see *Note show::. `INFORMATION_SCHEMA' has several tables that contain information similar to that displayed by the *Note `SHOW': show. statements. For example, the *Note `CHARACTER_SETS': character-sets-table. and *Note `COLLATIONS': collations-table. tables contain the information displayed by *Note `SHOW CHARACTER SET': show-character-set. and *Note `SHOW COLLATION': show-collation. See *Note information-schema::. The *Note `SHOW CHARACTER SET': show-character-set. statement shows all available character sets. It takes an optional `LIKE' clause that indicates which character set names to match. For example: mysql> SHOW CHARACTER SET LIKE 'latin%'; +---------+-----------------------------+-------------------+--------+ | Charset | Description | Default collation | Maxlen | +---------+-----------------------------+-------------------+--------+ | latin1 | cp1252 West European | latin1_swedish_ci | 1 | | latin2 | ISO 8859-2 Central European | latin2_general_ci | 1 | | latin5 | ISO 8859-9 Turkish | latin5_turkish_ci | 1 | | latin7 | ISO 8859-13 Baltic | latin7_general_ci | 1 | +---------+-----------------------------+-------------------+--------+ The output from *Note `SHOW COLLATION': show-collation. includes all available character sets. It takes an optional `LIKE' clause that indicates which collation names to match. For example: mysql> SHOW COLLATION LIKE 'latin1%'; +-------------------+---------+----+---------+----------+---------+ | Collation | Charset | Id | Default | Compiled | Sortlen | +-------------------+---------+----+---------+----------+---------+ | latin1_german1_ci | latin1 | 5 | | | 0 | | latin1_swedish_ci | latin1 | 8 | Yes | Yes | 0 | | latin1_danish_ci | latin1 | 15 | | | 0 | | latin1_german2_ci | latin1 | 31 | | Yes | 2 | | latin1_bin | latin1 | 47 | | Yes | 0 | | latin1_general_ci | latin1 | 48 | | | 0 | | latin1_general_cs | latin1 | 49 | | | 0 | | latin1_spanish_ci | latin1 | 94 | | | 0 | +-------------------+---------+----+---------+----------+---------+ *Note `SHOW CREATE DATABASE': show-create-database. displays the *Note `CREATE DATABASE': create-database. statement that creates a given database: mysql> SHOW CREATE DATABASE test; +----------+-----------------------------------------------------------------+ | Database | Create Database | +----------+-----------------------------------------------------------------+ | test | CREATE DATABASE `test` /*!40100 DEFAULT CHARACTER SET latin1 */ | +----------+-----------------------------------------------------------------+ If no `COLLATE' clause is shown, the default collation for the character set applies. *Note `SHOW CREATE TABLE': show-create-table. is similar, but displays the *Note `CREATE TABLE': create-table. statement to create a given table. The column definitions indicate any character set specifications, and the table options include character set information. The *Note `SHOW COLUMNS': show-columns. statement displays the collations of a table's columns when invoked as *Note `SHOW FULL COLUMNS': show-columns. Columns with *Note `CHAR': char, *Note `VARCHAR': char, or *Note `TEXT': blob. data types have collations. Numeric and other noncharacter types have no collation (indicated by `NULL' as the `Collation' value). For example: mysql> SHOW FULL COLUMNS FROM person\G *************************** 1. row *************************** Field: id Type: smallint(5) unsigned Collation: NULL Null: NO Key: PRI Default: NULL Extra: auto_increment Privileges: select,insert,update,references Comment: *************************** 2. row *************************** Field: name Type: char(60) Collation: latin1_swedish_ci Null: NO Key: Default: Extra: Privileges: select,insert,update,references Comment: The character set is not part of the display but is implied by the collation name.  File: manual.info, Node: charset-unicode, Next: charset-metadata, Prev: charset-operations, Up: charset 10.1.10 Unicode Support ----------------------- * Menu: * charset-unicode-ucs2:: The `ucs2' Character Set (UCS-2 Unicode Encoding) * charset-unicode-utf8:: The `utf8' Character Set (Three-Byte UTF-8 Unicode Encoding) MySQL 5.1 supports two character sets for storing Unicode data: * `ucs2', the UCS-2 encoding of the Unicode character set using 16 bits per character * `utf8', a UTF-8 encoding of the Unicode character set using one to three bytes per character These two character sets support the characters from the Basic Multilingual Plane (BMP) of Unicode Version 3.0. BMP characters have these characteristics: * Their code values are between 0 and 65535 (or `U+0000' .. `U+FFFF') * They can be encoded with a fixed 16-bit word, as in `ucs2' * They can be encoded with 8, 16, or 24 bits, as in `utf8' * They are sufficient for almost all characters in major languages The `ucs2' and `utf8' character sets do not support supplementary characters that lie outside the BMP. Characters outside the BMP compare as REPLACEMENT CHARACTER and convert to `'?'' when converted to a Unicode character set. A similar set of collations is available for each Unicode character set. For example, each has a Danish collation, the names of which are `ucs2_danish_ci' and `utf8_danish_ci'. All Unicode collations are listed at *Note charset-unicode-sets::. The MySQL implementation of UCS-2 stores characters in big-endian byte order and does not use a byte order mark (BOM) at the beginning of values. Other database systems might use little-endian byte order or a BOM. In such cases, conversion of values will need to be performed when transferring data between those systems and MySQL. MySQL uses no BOM for UTF-8 values. Client applications that need to communicate with the server using Unicode should set the client character set accordingly; for example, by issuing a `SET NAMES 'utf8'' statement. `ucs2' cannot be used as a client character set, which means that it does not work for `SET NAMES' or `SET CHARACTER SET'. (See *Note charset-connection::.) The following sections provide additional detail on the Unicode character sets in MySQL.  File: manual.info, Node: charset-unicode-ucs2, Next: charset-unicode-utf8, Prev: charset-unicode, Up: charset-unicode 10.1.10.1 The `ucs2' Character Set (UCS-2 Unicode Encoding) ........................................................... In UCS-2, every character is represented by a two-byte Unicode code with the most significant byte first. For example: `LATIN CAPITAL LETTER A' has the code `0x0041' and it is stored as a two-byte sequence: `0x00 0x41'. `CYRILLIC SMALL LETTER YERU' (Unicode `0x044B') is stored as a two-byte sequence: `0x04 0x4B'. For Unicode characters and their codes, please refer to the Unicode Home Page (http://www.unicode.org/). In MySQL, the `ucs2' character set is a fixed-length 16-bit encoding for Unicode BMP characters.  File: manual.info, Node: charset-unicode-utf8, Prev: charset-unicode-ucs2, Up: charset-unicode 10.1.10.2 The `utf8' Character Set (Three-Byte UTF-8 Unicode Encoding) ...................................................................... UTF-8 (Unicode Transformation Format with 8-bit units) is an alternative way to store Unicode data. It is implemented according to RFC 3629, which describes encoding sequences that take from one to four bytes. Currently, MySQL support for UTF-8 does not include four-byte sequences. (An older standard for UTF-8 encoding, RFC 2279, describes UTF-8 sequences that take from one to six bytes. RFC 3629 renders RFC 2279 obsolete; for this reason, sequences with five and six bytes are no longer used.) The idea of UTF-8 is that various Unicode characters are encoded using byte sequences of different lengths: * Basic Latin letters, digits, and punctuation signs use one byte. * Most European and Middle East script letters fit into a two-byte sequence: extended Latin letters (with tilde, macron, acute, grave and other accents), Cyrillic, Greek, Armenian, Hebrew, Arabic, Syriac, and others. * Korean, Chinese, and Japanese ideographs use three-byte sequences. *Tip*: To save space with UTF-8, use *Note `VARCHAR': char. instead of *Note `CHAR': char. Otherwise, MySQL must reserve three bytes for each character in a `CHAR CHARACTER SET utf8' column because that is the maximum possible length. For example, MySQL must reserve 30 bytes for a `CHAR(10) CHARACTER SET utf8' column.  File: manual.info, Node: charset-metadata, Next: charset-conversion, Prev: charset-unicode, Up: charset 10.1.11 UTF-8 for Metadata -------------------------- _Metadata_ is `the data about the data.' Anything that _describes_ the database--as opposed to being the _contents_ of the database--is metadata. Thus column names, database names, user names, version names, and most of the string results from *Note `SHOW': show. are metadata. This is also true of the contents of tables in `INFORMATION_SCHEMA' because those tables by definition contain information about database objects. Representation of metadata must satisfy these requirements: * All metadata must be in the same character set. Otherwise, neither the *Note `SHOW': show. statements nor *Note `SELECT': select. statements for tables in `INFORMATION_SCHEMA' would work properly because different rows in the same column of the results of these operations would be in different character sets. * Metadata must include all characters in all languages. Otherwise, users would not be able to name columns and tables using their own languages. To satisfy both requirements, MySQL stores metadata in a Unicode character set, namely UTF-8. This does not cause any disruption if you never use accented or non-Latin characters. But if you do, you should be aware that metadata is in UTF-8. The metadata requirements mean that the return values of the `USER()', `CURRENT_USER()', `SESSION_USER()', `SYSTEM_USER()', `DATABASE()', and `VERSION()' functions have the UTF-8 character set by default. The server sets the `character_set_system' system variable to the name of the metadata character set: mysql> SHOW VARIABLES LIKE 'character_set_system'; +----------------------+-------+ | Variable_name | Value | +----------------------+-------+ | character_set_system | utf8 | +----------------------+-------+ Storage of metadata using Unicode does _not_ mean that the server returns headers of columns and the results of *Note `DESCRIBE': describe. functions in the `character_set_system' character set by default. When you use `SELECT column1 FROM t', the name `column1' itself is returned from the server to the client in the character set determined by the value of the `character_set_results' system variable, which has a default value of `latin1'. If you want the server to pass metadata results back in a different character set, use the `SET NAMES' statement to force the server to perform character set conversion. `SET NAMES' sets the `character_set_results' and other related system variables. (See *Note charset-connection::.) Alternatively, a client program can perform the conversion after receiving the result from the server. It is more efficient for the client perform the conversion, but this option is not always available for all clients. If `character_set_results' is set to `NULL', no conversion is performed and the server returns metadata using its original character set (the set indicated by `character_set_system'). Error messages returned from the server to the client are converted to the client character set automatically, as with metadata. If you are using (for example) the `USER()' function for comparison or assignment within a single statement, don't worry. MySQL performs some automatic conversion for you. SELECT * FROM t1 WHERE USER() = latin1_column; This works because the contents of `latin1_column' are automatically converted to UTF-8 before the comparison. INSERT INTO t1 (latin1_column) SELECT USER(); This works because the contents of `USER()' are automatically converted to `latin1' before the assignment. Although automatic conversion is not in the SQL standard, the SQL standard document does say that every character set is (in terms of supported characters) a `subset' of Unicode. Because it is a well-known principle that `what applies to a superset can apply to a subset,' we believe that a collation for Unicode can apply for comparisons with non-Unicode strings. For more information about coercion of strings, see *Note charset-collation-expressions::.  File: manual.info, Node: charset-conversion, Next: charset-charsets, Prev: charset-metadata, Up: charset 10.1.12 Column Character Set Conversion --------------------------------------- To convert a binary or nonbinary string column to use a particular character set, use *Note `ALTER TABLE': alter-table. For successful conversion to occur, one of the following conditions must apply: * If the column has a binary data type (*Note `BINARY': binary-varbinary, *Note `VARBINARY': binary-varbinary, *Note `BLOB': blob.), all the values that it contains must be encoded using a single character set (the character set you're converting the column to). If you use a binary column to store information in multiple character sets, MySQL has no way to know which values use which character set and cannot convert the data properly. * If the column has a nonbinary data type (*Note `CHAR': char, *Note `VARCHAR': char, *Note `TEXT': blob.), its contents should be encoded in the column character set, not some other character set. If the contents are encoded in a different character set, you can convert the column to use a binary data type first, and then to a nonbinary column with the desired character set. Suppose that a table `t' has a binary column named `col1' defined as `VARBINARY(50)'. Assuming that the information in the column is encoded using a single character set, you can convert it to a nonbinary column that has that character set. For example, if `col1' contains binary data representing characters in the `greek' character set, you can convert it as follows: ALTER TABLE t MODIFY col1 VARCHAR(50) CHARACTER SET greek; If your original column has a type of `BINARY(50)', you could convert it to `CHAR(50)', but the resulting values will be padded with `0x00' bytes at the end, which may be undesirable. To remove these bytes, use the `TRIM()' function: UPDATE t SET col1 = TRIM(TRAILING 0x00 FROM col1); Suppose that table `t' has a nonbinary column named `col1' defined as `CHAR(50) CHARACTER SET latin1' but you want to convert it to use `utf8' so that you can store values from many languages. The following statement accomplishes this: ALTER TABLE t MODIFY col1 CHAR(50) CHARACTER SET utf8; Conversion may be lossy if the column contains characters that are not in both character sets. A special case occurs if you have old tables from before MySQL 4.1 where a nonbinary column contains values that actually are encoded in a character set different from the server's default character set. For example, an application might have stored `sjis' values in a column, even though MySQL's default character set was `latin1'. It is possible to convert the column to use the proper character set but an additional step is required. Suppose that the server's default character set was `latin1' and `col1' is defined as `CHAR(50)' but its contents are `sjis' values. The first step is to convert the column to a binary data type, which removes the existing character set information without performing any character conversion: ALTER TABLE t MODIFY col1 BLOB; The next step is to convert the column to a nonbinary data type with the proper character set: ALTER TABLE t MODIFY col1 CHAR(50) CHARACTER SET sjis; This procedure requires that the table not have been modified already with statements such as *Note `INSERT': insert. or *Note `UPDATE': update. after an upgrade to MySQL 4.1 or later. In that case, MySQL would store new values in the column using `latin1', and the column will contain a mix of `sjis' and `latin1' values and cannot be converted properly. If you specified attributes when creating a column initially, you should also specify them when altering the table with *Note `ALTER TABLE': alter-table. For example, if you specified `NOT NULL' and an explicit `DEFAULT' value, you should also provide them in the *Note `ALTER TABLE': alter-table. statement. Otherwise, the resulting column definition will not include those attributes.  File: manual.info, Node: charset-charsets, Prev: charset-conversion, Up: charset 10.1.13 Character Sets and Collations That MySQL Supports --------------------------------------------------------- * Menu: * charset-unicode-sets:: Unicode Character Sets * charset-we-sets:: West European Character Sets * charset-ce-sets:: Central European Character Sets * charset-se-me-sets:: South European and Middle East Character Sets * charset-baltic-sets:: Baltic Character Sets * charset-cyrillic-sets:: Cyrillic Character Sets * charset-asian-sets:: Asian Character Sets MySQL supports 70+ collations for 30+ character sets. This section indicates which character sets MySQL supports. There is one subsection for each group of related character sets. For each character set, the permissible collations are listed. You can always list the available character sets and their default collations with the *Note `SHOW CHARACTER SET': show-character-set. statement: mysql> SHOW CHARACTER SET; +----------+-----------------------------+---------------------+ | Charset | Description | Default collation | +----------+-----------------------------+---------------------+ | big5 | Big5 Traditional Chinese | big5_chinese_ci | | dec8 | DEC West European | dec8_swedish_ci | | cp850 | DOS West European | cp850_general_ci | | hp8 | HP West European | hp8_english_ci | | koi8r | KOI8-R Relcom Russian | koi8r_general_ci | | latin1 | cp1252 West European | latin1_swedish_ci | | latin2 | ISO 8859-2 Central European | latin2_general_ci | | swe7 | 7bit Swedish | swe7_swedish_ci | | ascii | US ASCII | ascii_general_ci | | ujis | EUC-JP Japanese | ujis_japanese_ci | | sjis | Shift-JIS Japanese | sjis_japanese_ci | | hebrew | ISO 8859-8 Hebrew | hebrew_general_ci | | tis620 | TIS620 Thai | tis620_thai_ci | | euckr | EUC-KR Korean | euckr_korean_ci | | koi8u | KOI8-U Ukrainian | koi8u_general_ci | | gb2312 | GB2312 Simplified Chinese | gb2312_chinese_ci | | greek | ISO 8859-7 Greek | greek_general_ci | | cp1250 | Windows Central European | cp1250_general_ci | | gbk | GBK Simplified Chinese | gbk_chinese_ci | | latin5 | ISO 8859-9 Turkish | latin5_turkish_ci | | armscii8 | ARMSCII-8 Armenian | armscii8_general_ci | | utf8 | UTF-8 Unicode | utf8_general_ci | | ucs2 | UCS-2 Unicode | ucs2_general_ci | | cp866 | DOS Russian | cp866_general_ci | | keybcs2 | DOS Kamenicky Czech-Slovak | keybcs2_general_ci | | macce | Mac Central European | macce_general_ci | | macroman | Mac West European | macroman_general_ci | | cp852 | DOS Central European | cp852_general_ci | | latin7 | ISO 8859-13 Baltic | latin7_general_ci | | cp1251 | Windows Cyrillic | cp1251_general_ci | | cp1256 | Windows Arabic | cp1256_general_ci | | cp1257 | Windows Baltic | cp1257_general_ci | | binary | Binary pseudo charset | binary | | geostd8 | GEOSTD8 Georgian | geostd8_general_ci | | cp932 | SJIS for Windows Japanese | cp932_japanese_ci | | eucjpms | UJIS for Windows Japanese | eucjpms_japanese_ci | +----------+-----------------------------+---------------------+ In cases where a character set has multiple collations, it might not be clear which collation is most suitable for a given application. To avoid choosing the wrong collation, it can be helpful to perform some comparisons with representative data values to make sure that a given collation sorts values the way you expect. Collation-Charts.Org (http://www.collation-charts.org/) is a useful site for information that shows how one collation compares to another.  File: manual.info, Node: charset-unicode-sets, Next: charset-we-sets, Prev: charset-charsets, Up: charset-charsets 10.1.13.1 Unicode Character Sets ................................ MySQL 5.1 has two Unicode character sets: * `ucs2', the UCS-2 encoding of the Unicode character set using 16 bits per character * `utf8', a UTF-8 encoding of the Unicode character set using one to three bytes per character You can store text in about 650 languages using these character sets. This section lists the collations available for each Unicode character set and describes their differentiating properties. For general information about the character sets, see *Note charset-unicode::. A similar set of collations is available for each Unicode character set. These are shown in the following list, where XXX represents the character set name. For example, `XXX_danish_ci' represents the Danish collations, the specific names of which are `ucs2_danish_ci' and `utf8_danish_ci'. * `XXX_bin' * `XXX_czech_ci' * `XXX_danish_ci' * `XXX_esperanto_ci' * `XXX_estonian_ci' * `XXX_general_ci' (default) * `XXX_hungarian_ci' * `XXX_icelandic_ci' * `XXX_latvian_ci' * `XXX_lithuanian_ci' * `XXX_persian_ci' * `XXX_polish_ci' * `XXX_roman_ci' * `XXX_romanian_ci' * `XXX_slovak_ci' * `XXX_slovenian_ci' * `XXX_spanish_ci' * `XXX_spanish2_ci' * `XXX_swedish_ci' * `XXX_turkish_ci' * `XXX_unicode_ci' The `XXX_hungarian_ci' collations were added in MySQL 5.1.5. MySQL implements the `XXX_unicode_ci' collations according to the Unicode Collation Algorithm (UCA) described at `http://www.unicode.org/reports/tr10/'. The collation uses the version-4.0.0 UCA weight keys: `http://www.unicode.org/Public/UCA/4.0.0/allkeys-4.0.0.txt'. Currently, the `XXX_unicode_ci' collations have only partial support for the Unicode Collation Algorithm. Some characters are not supported yet. Also, combining marks are not fully supported. This affects primarily Vietnamese, Yoruba, and some smaller languages such as Navajo. MySQL implements language-specific Unicode collations only if the ordering with `XXX_unicode_ci' does not work well for a language. Language-specific collations are UCA-based. They are derived from `XXX_unicode_ci' with additional language tailoring rules. For any Unicode character set, operations performed using the `XXX_general_ci' collation are faster than those for the `XXX_unicode_ci' collation. For example, comparisons for the `utf8_general_ci' collation are faster, but slightly less correct, than comparisons for `utf8_unicode_ci'. The reason for this is that `utf8_unicode_ci' supports mappings such as expansions; that is, when one character compares as equal to combinations of other characters. For example, in German and some other languages ``ss'' is equal to ``ss''. `utf8_unicode_ci' also supports contractions and ignorable characters. `utf8_general_ci' is a legacy collation that does not support expansions, contractions, or ignorable characters. It can make only one-to-one comparisons between characters. To further illustrate, the following equalities hold in both `utf8_general_ci' and `utf8_unicode_ci' (for the effect this has in comparisons or when doing searches, see *Note charset-collation-effect::): A" = A O" = O U" = U A difference between the collations is that this is true for `utf8_general_ci': ss = s Whereas this is true for `utf8_unicode_ci', which supports the German DIN-1 ordering (also known as dictionary order): ss = ss MySQL implements language-specific collations for the `utf8' character set only if the ordering with `utf8_unicode_ci' does not work well for a language. For example, `utf8_unicode_ci' works fine for German dictionary order and French, so there is no need to create special `utf8' collations. `utf8_general_ci' also is satisfactory for both German and French, except that ``ss'' is equal to ``s'', and not to ``ss''. If this is acceptable for your application, you should use `utf8_general_ci' because it is faster. Otherwise, use `utf8_unicode_ci' because it is more accurate. `XXX_swedish_ci' includes Swedish rules. For example, in Swedish, the following relationship holds, which is not something expected by a German or French speaker: U" = Y < O" The `XXX_spanish_ci' and `XXX_spanish2_ci' collations correspond to modern Spanish and traditional Spanish, respectively. In both collations, ``ñ'' (n-tilde) is a separate letter between ``n'' and ``o''. In addition, for traditional Spanish, ``ch'' is a separate letter between ``c'' and ``d'', and ``ll'' is a separate letter between ``l'' and ``m'' In the `XXX_roman_ci' collations, `I' and `J' compare as equal, and `U' and `V' compare as equal. For additional information about Unicode collations in MySQL, see Collation-Charts.Org (utf8 (http://www.collation-charts.org/mysql60/by-charset.html#utf8)).  File: manual.info, Node: charset-we-sets, Next: charset-ce-sets, Prev: charset-unicode-sets, Up: charset-charsets 10.1.13.2 West European Character Sets ...................................... Western European character sets cover most West European languages, such as French, Spanish, Catalan, Basque, Portuguese, Italian, Albanian, Dutch, German, Danish, Swedish, Norwegian, Finnish, Faroese, Icelandic, Irish, Scottish, and English. * `ascii' (US ASCII) collations: * `ascii_bin' * `ascii_general_ci' (default) * `cp850' (DOS West European) collations: * `cp850_bin' * `cp850_general_ci' (default) * `dec8' (DEC Western European) collations: * `dec8_bin' * `dec8_swedish_ci' (default) * `hp8' (HP Western European) collations: * `hp8_bin' * `hp8_english_ci' (default) * `latin1' (cp1252 West European) collations: * `latin1_bin' * `latin1_danish_ci' * `latin1_general_ci' * `latin1_general_cs' * `latin1_german1_ci' * `latin1_german2_ci' * `latin1_spanish_ci' * `latin1_swedish_ci' (default) `latin1' is the default character set. MySQL's `latin1' is the same as the Windows `cp1252' character set. This means it is the same as the official `ISO 8859-1' or IANA (Internet Assigned Numbers Authority) `latin1', except that IANA `latin1' treats the code points between `0x80' and `0x9f' as `undefined,' whereas `cp1252', and therefore MySQL's `latin1', assign characters for those positions. For example, `0x80' is the Euro sign. For the `undefined' entries in `cp1252', MySQL translates `0x81' to Unicode `0x0081', `0x8d' to `0x008d', `0x8f' to `0x008f', `0x90' to `0x0090', and `0x9d' to `0x009d'. The `latin1_swedish_ci' collation is the default that probably is used by the majority of MySQL customers. Although it is frequently said that it is based on the Swedish/Finnish collation rules, there are Swedes and Finns who disagree with this statement. The `latin1_german1_ci' and `latin1_german2_ci' collations are based on the DIN-1 and DIN-2 standards, where DIN stands for _Deutsches Institut fu"r Normung_ (the German equivalent of ANSI). DIN-1 is called the `dictionary collation' and DIN-2 is called the `phone book collation.' For an example of the effect this has in comparisons or when doing searches, see *Note charset-collation-effect::. * `latin1_german1_ci' (dictionary) rules: A" = A O" = O U" = U ss = s * `latin1_german2_ci' (phone-book) rules: A" = AE O" = OE U" = UE ss = ss In the `latin1_spanish_ci' collation, ``ñ'' (n-tilde) is a separate letter between ``n'' and ``o''. * `macroman' (Mac West European) collations: * `macroman_bin' * `macroman_general_ci' (default) * `swe7' (7bit Swedish) collations: * `swe7_bin' * `swe7_swedish_ci' (default) For additional information about Western European collations in MySQL, see Collation-Charts.Org (ascii (http://www.collation-charts.org/mysql60/by-charset.html#ascii), cp850 (http://www.collation-charts.org/mysql60/by-charset.html#cp850), dec8 (http://www.collation-charts.org/mysql60/by-charset.html#dec8), hp8 (http://www.collation-charts.org/mysql60/by-charset.html#hp8), latin1 (http://www.collation-charts.org/mysql60/by-charset.html#latin1), macroman (http://www.collation-charts.org/mysql60/by-charset.html#macroman), swe7 (http://www.collation-charts.org/mysql60/by-charset.html#swe7)).  File: manual.info, Node: charset-ce-sets, Next: charset-se-me-sets, Prev: charset-we-sets, Up: charset-charsets 10.1.13.3 Central European Character Sets ......................................... MySQL provides some support for character sets used in the Czech Republic, Slovakia, Hungary, Romania, Slovenia, Croatia, Poland, and Serbia (Latin). * `cp1250' (Windows Central European) collations: * `cp1250_bin' * `cp1250_croatian_ci' * `cp1250_czech_cs' * `cp1250_general_ci' (default) * `cp1250_polish_ci' * `cp852' (DOS Central European) collations: * `cp852_bin' * `cp852_general_ci' (default) * `keybcs2' (DOS Kamenicky Czech-Slovak) collations: * `keybcs2_bin' * `keybcs2_general_ci' (default) * `latin2' (ISO 8859-2 Central European) collations: * `latin2_bin' * `latin2_croatian_ci' * `latin2_czech_cs' * `latin2_general_ci' (default) * `latin2_hungarian_ci' * `macce' (Mac Central European) collations: * `macce_bin' * `macce_general_ci' (default) For additional information about Central European collations in MySQL, see Collation-Charts.Org (cp1250 (http://www.collation-charts.org/mysql60/by-charset.html#cp1250), cp852 (http://www.collation-charts.org/mysql60/by-charset.html#cp852), keybcs2 (http://www.collation-charts.org/mysql60/by-charset.html#keybcs2), latin2 (http://www.collation-charts.org/mysql60/by-charset.html#latin2), macce (http://www.collation-charts.org/mysql60/by-charset.html#macce)).  File: manual.info, Node: charset-se-me-sets, Next: charset-baltic-sets, Prev: charset-ce-sets, Up: charset-charsets 10.1.13.4 South European and Middle East Character Sets ....................................................... South European and Middle Eastern character sets supported by MySQL include Armenian, Arabic, Georgian, Greek, Hebrew, and Turkish. * `armscii8' (ARMSCII-8 Armenian) collations: * `armscii8_bin' * `armscii8_general_ci' (default) * `cp1256' (Windows Arabic) collations: * `cp1256_bin' * `cp1256_general_ci' (default) * `geostd8' (GEOSTD8 Georgian) collations: * `geostd8_bin' * `geostd8_general_ci' (default) * `greek' (ISO 8859-7 Greek) collations: * `greek_bin' * `greek_general_ci' (default) * `hebrew' (ISO 8859-8 Hebrew) collations: * `hebrew_bin' * `hebrew_general_ci' (default) * `latin5' (ISO 8859-9 Turkish) collations: * `latin5_bin' * `latin5_turkish_ci' (default) For additional information about South European and Middle Eastern collations in MySQL, see Collation-Charts.Org (armscii8 (http://www.collation-charts.org/mysql60/by-charset.html#armscii8), cp1256 (http://www.collation-charts.org/mysql60/by-charset.html#cp1256), geostd8 (http://www.collation-charts.org/mysql60/by-charset.html#geostd8), greek (http://www.collation-charts.org/mysql60/by-charset.html#greek), hebrew (http://www.collation-charts.org/mysql60/by-charset.html#hebrew), latin5 (http://www.collation-charts.org/mysql60/by-charset.html#latin5)).  File: manual.info, Node: charset-baltic-sets, Next: charset-cyrillic-sets, Prev: charset-se-me-sets, Up: charset-charsets 10.1.13.5 Baltic Character Sets ............................... The Baltic character sets cover Estonian, Latvian, and Lithuanian languages. * `cp1257' (Windows Baltic) collations: * `cp1257_bin' * `cp1257_general_ci' (default) * `cp1257_lithuanian_ci' * `latin7' (ISO 8859-13 Baltic) collations: * `latin7_bin' * `latin7_estonian_cs' * `latin7_general_ci' (default) * `latin7_general_cs' For additional information about Baltic collations in MySQL, see Collation-Charts.Org (cp1257 (http://www.collation-charts.org/mysql60/by-charset.html#cp1257), latin7 (http://www.collation-charts.org/mysql60/by-charset.html#latin7)).  File: manual.info, Node: charset-cyrillic-sets, Next: charset-asian-sets, Prev: charset-baltic-sets, Up: charset-charsets 10.1.13.6 Cyrillic Character Sets ................................. The Cyrillic character sets and collations are for use with Belarusian, Bulgarian, Russian, Ukrainian, and Serbian (Cyrillic) languages. * `cp1251' (Windows Cyrillic) collations: * `cp1251_bin' * `cp1251_bulgarian_ci' * `cp1251_general_ci' (default) * `cp1251_general_cs' * `cp1251_ukrainian_ci' * `cp866' (DOS Russian) collations: * `cp866_bin' * `cp866_general_ci' (default) * `koi8r' (KOI8-R Relcom Russian) collations: * `koi8r_bin' * `koi8r_general_ci' (default) * `koi8u' (KOI8-U Ukrainian) collations: * `koi8u_bin' * `koi8u_general_ci' (default) For additional information about Cyrillic collations in MySQL, see Collation-Charts.Org (cp1251 (http://www.collation-charts.org/mysql60/by-charset.html#cp1251), cp866 (http://www.collation-charts.org/mysql60/by-charset.html#cp866), koi8r (http://www.collation-charts.org/mysql60/by-charset.html#koi8r), koi8u (http://www.collation-charts.org/mysql60/by-charset.html#koi8u)). ).  File: manual.info, Node: charset-asian-sets, Prev: charset-cyrillic-sets, Up: charset-charsets 10.1.13.7 Asian Character Sets .............................. * Menu: * charset-cp932:: The `cp932' Character Set The Asian character sets that we support include Chinese, Japanese, Korean, and Thai. These can be complicated. For example, the Chinese sets must allow for thousands of different characters. See *Note charset-cp932::, for additional information about the `cp932' and `sjis' character sets. For answers to some common questions and problems relating support for Asian character sets in MySQL, see *Note faqs-cjk::. * `big5' (Big5 Traditional Chinese) collations: * `big5_bin' * `big5_chinese_ci' (default) * `cp932' (SJIS for Windows Japanese) collations: * `cp932_bin' * `cp932_japanese_ci' (default) * `eucjpms' (UJIS for Windows Japanese) collations: * `eucjpms_bin' * `eucjpms_japanese_ci' (default) * `euckr' (EUC-KR Korean) collations: * `euckr_bin' * `euckr_korean_ci' (default) * `gb2312' (GB2312 Simplified Chinese) collations: * `gb2312_bin' * `gb2312_chinese_ci' (default) * `gbk' (GBK Simplified Chinese) collations: * `gbk_bin' * `gbk_chinese_ci' (default) * `sjis' (Shift-JIS Japanese) collations: * `sjis_bin' * `sjis_japanese_ci' (default) * `tis620' (TIS620 Thai) collations: * `tis620_bin' * `tis620_thai_ci' (default) * `ujis' (EUC-JP Japanese) collations: * `ujis_bin' * `ujis_japanese_ci' (default) The `big5_chinese_ci' collation sorts on number of strokes. For additional information about Asian collations in MySQL, see Collation-Charts.Org (big5 (http://www.collation-charts.org/mysql60/by-charset.html#big5), cp932 (http://www.collation-charts.org/mysql60/by-charset.html#cp932), eucjpms (http://www.collation-charts.org/mysql60/by-charset.html#eucjpms), euckr (http://www.collation-charts.org/mysql60/by-charset.html#euckr), gb2312 (http://www.collation-charts.org/mysql60/by-charset.html#gb2312), gbk (http://www.collation-charts.org/mysql60/by-charset.html#gbk), sjis (http://www.collation-charts.org/mysql60/by-charset.html#sjis), tis620 (http://www.collation-charts.org/mysql60/by-charset.html#tis620), ujis (http://www.collation-charts.org/mysql60/by-charset.html#ujis)).  File: manual.info, Node: charset-cp932, Prev: charset-asian-sets, Up: charset-asian-sets 10.1.13.8 The `cp932' Character Set ................................... *Why is `cp932' needed?* In MySQL, the `sjis' character set corresponds to the `Shift_JIS' character set defined by IANA, which supports JIS X0201 and JIS X0208 characters. (See `http://www.iana.org/assignments/character-sets'.) However, the meaning of `SHIFT JIS' as a descriptive term has become very vague and it often includes the extensions to `Shift_JIS' that are defined by various vendors. For example, `SHIFT JIS' used in Japanese Windows environments is a Microsoft extension of `Shift_JIS' and its exact name is `Microsoft Windows Codepage : 932' or `cp932'. In addition to the characters supported by `Shift_JIS', `cp932' supports extension characters such as NEC special characters, NEC selected--IBM extended characters, and IBM extended characters. Many Japanese users have experienced problems using these extension characters. These problems stem from the following factors: * MySQL automatically converts character sets. * Character sets are converted using Unicode (`ucs2'). * The `sjis' character set does not support the conversion of these extension characters. * There are several conversion rules from so-called `SHIFT JIS' to Unicode, and some characters are converted to Unicode differently depending on the conversion rule. MySQL supports only one of these rules (described later). The MySQL `cp932' character set is designed to solve these problems. Because MySQL supports character set conversion, it is important to separate IANA `Shift_JIS' and `cp932' into two different character sets because they provide different conversion rules. *How does `cp932' differ from `sjis'?* The `cp932' character set differs from `sjis' in the following ways: * `cp932' supports NEC special characters, NEC selected--IBM extended characters, and IBM selected characters. * Some `cp932' characters have two different code points, both of which convert to the same Unicode code point. When converting from Unicode back to `cp932', one of the code points must be selected. For this `round trip conversion,' the rule recommended by Microsoft is used. (See `http://support.microsoft.com/kb/170559/EN-US/'.) The conversion rule works like this: * If the character is in both JIS X 0208 and NEC special characters, use the code point of JIS X 0208. * If the character is in both NEC special characters and IBM selected characters, use the code point of NEC special characters. * If the character is in both IBM selected characters and NEC selected--IBM extended characters, use the code point of IBM extended characters. The table shown at `http://www.microsoft.com/globaldev/reference/dbcs/932.htm' provides information about the Unicode values of `cp932' characters. For `cp932' table entries with characters under which a four-digit number appears, the number represents the corresponding Unicode (`ucs2') encoding. For table entries with an underlined two-digit value appears, there is a range of `cp932' character values that begin with those two digits. Clicking such a table entry takes you to a page that displays the Unicode value for each of the `cp932' characters that begin with those digits. The following links are of special interest. They correspond to the encodings for the following sets of characters: * NEC special characters: `http://www.microsoft.com/globaldev/reference/dbcs/932/932_87.htm' * NEC selected--IBM extended characters: `http://www.microsoft.com/globaldev/reference/dbcs/932/932_ED.htm' `http://www.microsoft.com/globaldev/reference/dbcs/932/932_EE.htm' * IBM selected characters: `http://www.microsoft.com/globaldev/reference/dbcs/932/932_FA.htm' `http://www.microsoft.com/globaldev/reference/dbcs/932/932_FB.htm' `http://www.microsoft.com/globaldev/reference/dbcs/932/932_FC.htm' * `cp932' supports conversion of user-defined characters in combination with `eucjpms', and solves the problems with `sjis'/`ujis' conversion. For details, please refer to `http://www.opengroup.or.jp/jvc/cde/sjis-euc-e.html'. For some characters, conversion to and from `ucs2' is different for `sjis' and `cp932'. The following tables illustrate these differences. Conversion to `ucs2': `sjis'/`cp932' Value `sjis' -> `ucs2' `cp932' -> `ucs2' Conversion Conversion 5C 005C 005C 7E 007E 007E 815C 2015 2015 815F 005C FF3C 8160 301C FF5E 8161 2016 2225 817C 2212 FF0D 8191 00A2 FFE0 8192 00A3 FFE1 81CA 00AC FFE2 Conversion from `ucs2': `ucs2' value `ucs2' -> `sjis' `ucs2' -> `cp932' Conversion Conversion 005C 815F 5C 007E 7E 7E 00A2 8191 3F 00A3 8192 3F 00AC 81CA 3F 2015 815C 815C 2016 8161 3F 2212 817C 3F 2225 3F 8161 301C 8160 3F FF0D 3F 817C FF3C 3F 815F FF5E 3F 8160 FFE0 3F 8191 FFE1 3F 8192 FFE2 3F 81CA Users of any Japanese character sets should be aware that using `--character-set-client-handshake' (or `--skip-character-set-client-handshake') has an important effect. See *Note server-options::.  File: manual.info, Node: error-message-language, Next: adding-character-set, Prev: charset, Up: globalization 10.2 Setting the Error Message Language ======================================= By default, *Note `mysqld': mysqld. produces error messages in English, but they can also be displayed in any of several other languages: Czech, Danish, Dutch, Estonian, French, German, Greek, Hungarian, Italian, Japanese, Korean, Norwegian, Norwegian-ny, Polish, Portuguese, Romanian, Russian, Slovak, Spanish, or Swedish. You can select which language the server uses for error messages using the instructions in this section. To start *Note `mysqld': mysqld. with a particular language for error messages, use the `--language' or `-L' option. The option value can be a language name or the full path to the error message file. For example: shell> mysqld --language=swedish Or: shell> mysqld --language=/usr/local/share/swedish The language name should be specified in lowercase. By default, the language files are located in the `share/mysql/LANGUAGE' directory under the MySQL base directory. For information about changing the character set for error messages (rather than the language), see *Note charset-errors::. You can change the content of the error messages produced by the server using the instructions in the MySQL Internals manual, available at `http://forge.mysql.com/wiki/MySQL_Internals_Error_Messages'. If you do change the content of error messages, remember to repeat your changes after each upgrade to a newer version of MySQL.  File: manual.info, Node: adding-character-set, Next: adding-collation, Prev: error-message-language, Up: globalization 10.3 Adding a Character Set =========================== * Menu: * character-arrays:: Character Definition Arrays * string-collating:: String Collating Support for Complex Character Sets * multi-byte-characters:: Multi-Byte Character Support for Complex Character Sets This section discusses the procedure for adding a character set to MySQL. The proper procedure depends on whether the character set is simple or complex: * If the character set does not need special string collating routines for sorting and does not need multi-byte character support, it is simple. * If the character set needs either of those features, it is complex. For example, `greek' and `swe7' are simple character sets, whereas `big5' and `czech' are complex character sets. To use the following instructions, you must have a MySQL source distribution. In the instructions, MYSET represents the name of the character set that you want to add. 1. Add a `' element for MYSET to the `sql/share/charsets/Index.xml' file. Use the existing contents in the file as a guide to adding new contents. A partial listing for the `latin1' `' element follows: Western cp1252 West European ... primary compiled ... binary compiled ... The `' element must list all the collations for the character set. These must include at least a binary collation and a default (primary) collation. The default collation is often named using a suffix of `general_ci' (general, case insensitive). It is possible for the binary collation to be the default collation, but usually they are different. The default collation should have a `primary' flag. The binary collation should have a `binary' flag. You must assign a unique ID number to each collation, chosen from the range 1 to 254. To find the maximum of the currently used collation IDs, use this query: SELECT MAX(ID) FROM INFORMATION_SCHEMA.COLLATIONS; 2. This step depends on whether you are adding a simple or complex character set. A simple character set requires only a configuration file, whereas a complex character set requires C source file that defines collation functions, multi-byte functions, or both. For a simple character set, create a configuration file, `MYSET.xml', that describes the character set properties. Create this file in the `sql/share/charsets' directory. You can use a copy of `latin1.xml' as the basis for this file. The syntax for the file is very simple: * Comments are written as ordinary XML comments (`'). * Words within `' array elements are separated by arbitrary amounts of whitespace. * Each word within `' array elements must be a number in hexadecimal format. * The `' array element for the `' element has 257 words. The other `' array elements after that have 256 words. See *Note character-arrays::. * For each collation listed in the `' element for the character set in `Index.xml', `MYSET.xml' must contain a `' element that defines the character ordering. For a complex character set, create a C source file that describes the character set properties and defines the support routines necessary to properly perform operations on the character set: * Create the file `ctype-MYSET.c' in the `strings' directory. Look at one of the existing `ctype-*.c' files (such as `ctype-big5.c') to see what needs to be defined. The arrays in your file must have names like `ctype_MYSET', `to_lower_MYSET', and so on. These correspond to the arrays for a simple character set. See *Note character-arrays::. * For each `' element listed in the `' element for the character set in `Index.xml', the `ctype-MYSET.c' file must provide an implementation of the collation. * If the character set requires string collating functions, see *Note string-collating::. * If the character set requires multi-byte character support, see *Note multi-byte-characters::. 3. Modify the configuration information. Use the existing configuration information as a guide to adding information for MYSYS. The example here assumes that the character set has default and binary collations, but more lines are needed if MYSET has additional collations. 1. Edit `mysys/charset-def.c', and `register' the collations for the new character set. Add these lines to the `declaration' section: #ifdef HAVE_CHARSET_MYSET extern CHARSET_INFO my_charset_MYSET_general_ci; extern CHARSET_INFO my_charset_MYSET_bin; #endif Add these lines to the `registration' section: #ifdef HAVE_CHARSET_MYSET add_compiled_collation(&my_charset_MYSET_general_ci); add_compiled_collation(&my_charset_MYSET_bin); #endif 2. If the character set uses `ctype-MYSET.c', edit `strings/Makefile.am' and add `ctype-MYSET.c' to each definition of the `CSRCS' variable, and to the `EXTRA_DIST' variable. 3. If the character set uses `ctype-MYSET.c', edit `libmysql/Makefile.shared' and add `ctype-MYSET.lo' to the `mystringsobjects' definition. 4. Edit `config/ac-macros/character_sets.m4': 1. Add MYSET to one of the `define(CHARSETS_AVAILABLE...)' lines in alphabetic order. 2. Add MYSET to `CHARSETS_COMPLEX'. This is needed even for simple character sets, or `configure' will not recognize `--with-charset=MYSET'. 3. Add MYSET to the first `case' control structure. Omit the `USE_MB' and `USE_MB_IDENT' lines for 8-bit character sets. MYSET) AC_DEFINE(HAVE_CHARSET_MYSET, 1, [Define to enable charset MYSET]) AC_DEFINE([USE_MB], 1, [Use multi-byte character routines]) AC_DEFINE(USE_MB_IDENT, 1) ;; 4. Add MYSET to the second `case' control structure: MYSET) default_charset_default_collation="MYSET_general_ci" default_charset_collations="MYSET_general_ci MYSET_bin" ;; 4. Reconfigure, recompile, and test.  File: manual.info, Node: character-arrays, Next: string-collating, Prev: adding-character-set, Up: adding-character-set 10.3.1 Character Definition Arrays ---------------------------------- Each simple character set has a configuration file located in the `sql/share/charsets' directory. For a character set named MYSYS, the file is named `MYSET.xml'. It uses `' array elements to list character set properties. `' elements appear within these elements: * `' defines attributes for each character. * `' and `' list the lowercase and uppercase characters. * `' maps 8-bit character values to Unicode values. * `' elements indicate character ordering for comparisons and sorts, one element per collation. Binary collations need no `' element because the character codes themselves provide the ordering. For a complex character set as implemented in a `ctype-MYSET.c' file in the `strings' directory, there are corresponding arrays: `ctype_MYSET[]', `to_lower_MYSET[]', and so forth. Not every complex character set has all of the arrays. See also the existing `ctype-*.c' files for examples. See the `CHARSET_INFO.txt' file in the `strings' directory for additional information. Most of the arrays are indexed by character value and have 256 elements. The `' array is indexed by character value + 1 and has 257 elements. This is a legacy convention for handling `EOF'. `' array elements are bit values. Each element describes the attributes of a single character in the character set. Each attribute is associated with a bitmask, as defined in `include/m_ctype.h': #define _MY_U 01 /* Upper case */ #define _MY_L 02 /* Lower case */ #define _MY_NMR 04 /* Numeral (digit) */ #define _MY_SPC 010 /* Spacing character */ #define _MY_PNT 020 /* Punctuation */ #define _MY_CTR 040 /* Control character */ #define _MY_B 0100 /* Blank */ #define _MY_X 0200 /* heXadecimal digit */ The `' value for a given character should be the union of the applicable bitmask values that describe the character. For example, `'A'' is an uppercase character (`_MY_U') as well as a hexadecimal digit (`_MY_X'), so its `ctype' value should be defined like this: ctype['A'+1] = _MY_U | _MY_X = 01 | 0200 = 0201 The bitmask values in `m_ctype.h' are octal values, but the elements of the `' array in `MYSET.xml' should be written as hexadecimal values. The `' and `' arrays hold the lowercase and uppercase characters corresponding to each member of the character set. For example: lower['A'] should contain 'a' upper['a'] should contain 'A' Each `' array indicates how characters should be ordered for comparison and sorting purposes. MySQL sorts characters based on the values of this information. In some cases, this is the same as the `' array, which means that sorting is case-insensitive. For more complicated sorting rules (for complex character sets), see the discussion of string collating in *Note string-collating::.  File: manual.info, Node: string-collating, Next: multi-byte-characters, Prev: character-arrays, Up: adding-character-set 10.3.2 String Collating Support for Complex Character Sets ---------------------------------------------------------- For a simple character set named MYSET, sorting rules are specified in the `MYSET.xml' configuration file using `' array elements within `' elements. If the sorting rules for your language are too complex to be handled with simple arrays, you must define string collating functions in the `ctype-MYSET.c' source file in the `strings' directory. The existing character sets provide the best documentation and examples to show how these functions are implemented. Look at the `ctype-*.c' files in the `strings' directory, such as the files for the `big5', `czech', `gbk', `sjis', and `tis160' character sets. Take a look at the `MY_COLLATION_HANDLER' structures to see how they are used. See also the `CHARSET_INFO.txt' file in the `strings' directory for additional information.  File: manual.info, Node: multi-byte-characters, Prev: string-collating, Up: adding-character-set 10.3.3 Multi-Byte Character Support for Complex Character Sets -------------------------------------------------------------- If you want to add support for a new character set named MYSET that includes multi-byte characters, you must use multi-byte character functions in the `ctype-MYSET.c' source file in the `strings' directory. The existing character sets provide the best documentation and examples to show how these functions are implemented. Look at the `ctype-*.c' files in the `strings' directory, such as the files for the `euc_kr', `gb2312', `gbk', `sjis', and `ujis' character sets. Take a look at the `MY_CHARSET_HANDLER' structures to see how they are used. See also the `CHARSET_INFO.txt' file in the `strings' directory for additional information.  File: manual.info, Node: adding-collation, Next: charset-configuration, Prev: adding-character-set, Up: globalization 10.4 Adding a Collation to a Character Set ========================================== * Menu: * charset-collation-implementations:: Collation Implementation Types * adding-collation-choosing-id:: Choosing a Collation ID * adding-collation-simple-8bit:: Adding a Simple Collation to an 8-Bit Character Set * adding-collation-unicode-uca:: Adding a UCA Collation to a Unicode Character Set A collation is a set of rules that defines how to compare and sort character strings. Each collation in MySQL belongs to a single character set. Every character set has at least one collation, and most have two or more collations. A collation orders characters based on weights. Each character in a character set maps to a weight. Characters with equal weights compare as equal, and characters with unequal weights compare according to the relative magnitude of their weights. MySQL supports several collation implementations, as discussed in *Note charset-collation-implementations::. Some of these can be added to MySQL without recompiling: * Simple collations for 8-bit character sets * UCA-based collations for Unicode character sets * Binary (`XXX_bin') collations The following sections describe how to add collations of the first two types to existing character sets. All existing character sets already have a binary collation, so there is no need here to describe how to add one. Summary of the procedure for adding a new collation: 1. Choose a collation ID 2. Add configuration information that names the collation and describes the character-ordering rules 3. Restart the server 4. Verify that the collation is present The instructions here cover only collations that can be added without recompiling MySQL. To add a collation that does require recompiling (as implemented by means of functions in a C source file), use the instructions in *Note adding-character-set::. However, instead of adding all the information required for a complete character set, just modify the appropriate files for an existing character set. That is, based on what is already present for the character set's current collations, add data structures, functions, and configuration information for the new collation. *Note*: If you modify an existing collation, that may affect the ordering of rows for indexes on columns that use the collation. In this case, rebuild any such indexes to avoid problems such as incorrect query results. For further information, see *Note checking-table-incompatibilities::. * Additional Resources * * The Unicode Collation Algorithm (UCA) specification: `http://www.unicode.org/reports/tr10/' * The Locale Data Markup Language (LDML) specification: `http://www.unicode.org/reports/tr35/' * MySQL University session `How to Add a Collation': `http://forge.mysql.com/wiki/How_to_Add_a_Collation' * MySQL Blog article `Instructions for adding a new Unicode collation': `http://blogs.mysql.com/peterg/2008/05/19/instructions-for-adding-a-new-unicode-collation/'  File: manual.info, Node: charset-collation-implementations, Next: adding-collation-choosing-id, Prev: adding-collation, Up: adding-collation 10.4.1 Collation Implementation Types ------------------------------------- MySQL implements several types of collations: *Simple collations for 8-bit character sets* This kind of collation is implemented using an array of 256 weights that defines a one-to-one mapping from character codes to weights. `latin1_swedish_ci' is an example. It is a case-insensitive collation, so the uppercase and lowercase versions of a character have the same weights and they compare as equal. mysql> SET NAMES 'latin1' COLLATE 'latin1_swedish_ci'; Query OK, 0 rows affected (0.00 sec) mysql> SELECT 'a' = 'A'; +-----------+ | 'a' = 'A' | +-----------+ | 1 | +-----------+ 1 row in set (0.00 sec) For implementation instructions, see *Note adding-collation-simple-8bit::. *Complex collations for 8-bit character sets* This kind of collation is implemented using functions in a C source file that define how to order characters, as described in *Note adding-character-set::. *Collations for non-Unicode multi-byte character sets* For this type of collation, 8-bit (single-byte) and multi-byte characters are handled differently. For 8-bit characters, character codes map to weights in case-insensitive fashion. (For example, the single-byte characters `'a'' and `'A'' both have a weight of `0x41'.) For multi-byte characters, there are two types of relationship between character codes and weights: * Weights equal character codes. `sjis_japanese_ci' is an example of this kind of collation. The multi-byte character `'ぢ'' has a character code of `0x82C0', and the weight is also `0x82C0'. * Character codes map one-to-one to weights, but a code is not necessarily equal to the weight. `gbk_chinese_ci' is an example of this kind of collation. The multi-byte character `'膰'' has a character code of `0x81B0' but a weight of `0xC286'. For implementation instructions, see *Note adding-character-set::. *Collations for Unicode multi-byte character sets* Some of these collations are based on the Unicode Collation Algorithm (UCA), others are not. Non-UCA collations have a one-to-one mapping from character code to weight. In MySQL, such collations are case insensitive and accent insensitive. `utf8_general_ci' is an example: `'a'', `'A'', `'A`'', and `'a''' each have different character codes but all have a weight of `0x0041' and compare as equal. mysql> SET NAMES 'utf8' COLLATE 'utf8_general_ci'; Query OK, 0 rows affected (0.00 sec) mysql> SELECT 'a' = 'A', 'a' = 'A`', 'a' = 'a''; +-----------+-----------+-----------+ | 'a' = 'A' | 'a' = 'A`' | 'a' = 'a'' | +-----------+-----------+-----------+ | 1 | 1 | 1 | +-----------+-----------+-----------+ 1 row in set (0.06 sec) UCA-based collations in MySQL have these properties: * If a character has weights, each weight uses 2 bytes (16 bits) * A character may have zero weights (or an empty weight). In this case, the character is ignorable. Example: "U+0000 NULL" does not have a weight and is ignorable. * A character may have one weight. Example: `'a'' has a weight of `0x0E33'. * A character may have many weights. This is an expansion. Example: The German letter `'ss'' (SZ ligature, or SHARP S) has a weight of `0x0FEA0FEA'. * Many characters may have one weight. This is a contraction. Example: `'ch'' is a single letter in Czech and has a weight of `0x0EE2'. A many-characters-to-many-weights mapping is also possible (this is contraction with expansion), but is not supported by MySQL. For implementation instructions, for a non-UCA colluation, see *Note adding-character-set::. For a UCA collation, see *Note adding-collation-unicode-uca::. *Miscellaneous collations* There are also a few collations that do not fall into any of the previous categories.  File: manual.info, Node: adding-collation-choosing-id, Next: adding-collation-simple-8bit, Prev: charset-collation-implementations, Up: adding-collation 10.4.2 Choosing a Collation ID ------------------------------ Each collation must have a unique ID. To add a collation, you must choose an ID value that is not currently used. The value must be in the range from 1 to 254. The collation ID that you choose will appear in these contexts: * The `ID' column of the *Note `INFORMATION_SCHEMA.COLLATIONS': collations-table. table * The `Id' column of *Note `SHOW COLLATION': show-collation. output * The `charsetnr' member of the `MYSQL_FIELD' C API data structure * The `number' member of the `MY_CHARSET_INFO' data structure returned by the *Note `mysql_get_character_set_info()': mysql-get-character-set-info. C API function To determine the largest currently used ID, issue the following statement: mysql> SELECT MAX(ID) FROM INFORMATION_SCHEMA.COLLATIONS; +---------+ | MAX(ID) | +---------+ | 210 | +---------+ For the output just shown, you could choose an ID higher than 210 for the new collation. To display a list of all currently used IDs, issue this statement: mysql> SELECT ID FROM INFORMATION_SCHEMA.COLLATIONS ORDER BY ID; +-----+ | ID | +-----+ | 1 | | 2 | | ... | | 52 | | 53 | | 57 | | 58 | | ... | | 98 | | 99 | | 128 | | 129 | | ... | | 210 | +-----+ In this case, you can either choose an unused ID from within the current range of IDs, or choose an ID that is higher than the current maximum ID. For example, in the output just shown, there are unused IDs between 53 and 57, and between 99 and 128. Or you could choose an ID higher than 210. *Warning*: If you upgrade MySQL, you may find that the collation ID you choose has been assigned to a collation included in the new MySQL distribution. In this case, you will need to choose a new value for your own collation. In addition, before upgrading, you should save the configuration files that you change. If you upgrade in place, the process will replace the your modified files.  File: manual.info, Node: adding-collation-simple-8bit, Next: adding-collation-unicode-uca, Prev: adding-collation-choosing-id, Up: adding-collation 10.4.3 Adding a Simple Collation to an 8-Bit Character Set ---------------------------------------------------------- This section describes how to add a simple collation for an 8-bit character set by writing the `' elements associated with a `' character set description in the MySQL `Index.xml' file. The procedure described here does not require recompiling MySQL. The example adds a collation named `latin1_test_ci' to the `latin1' character set. 1. Choose a collation ID, as shown in *Note adding-collation-choosing-id::. The following steps use an ID of 56. 2. Modify the `Index.xml' and `latin1.xml' configuration files. These files will be located in the directory named by the `character_sets_dir' system variable. You can check the variable value as follows, although the path name might be different on your system: mysql> SHOW VARIABLES LIKE 'character_sets_dir'; +--------------------+-----------------------------------------+ | Variable_name | Value | +--------------------+-----------------------------------------+ | character_sets_dir | /user/local/mysql/share/mysql/charsets/ | +--------------------+-----------------------------------------+ 3. Choose a name for the collation and list it in the `Index.xml' file. Find the `' element for the character set to which the collation is being added, and add a `' element that indicates the collation name and ID, to associate the name with the ID. For example: ... ... 4. In the `latin1.xml' configuration file, add a `' element that names the collation and that contains a `' element that defines a character code-to-weight mapping table for character codes 0 to 255. Each value within the `' element must be a number in hexadecimal format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estart the server and use this statement to verify that the collation is present: mysql> SHOW COLLATION LIKE 'latin1_test_ci'; +----------------+---------+----+---------+----------+---------+ | Collation | Charset | Id | Default | Compiled | Sortlen | +----------------+---------+----+---------+----------+---------+ | latin1_test_ci | latin1 | 56 | | | 1 | +----------------+---------+----+---------+----------+---------+  File: manual.info, Node: adding-collation-unicode-uca, Prev: adding-collation-simple-8bit, Up: adding-collation 10.4.4 Adding a UCA Collation to a Unicode Character Set -------------------------------------------------------- * Menu: * ldml-collation-example:: Defining a UCA Collation using LDML Syntax * ldml-rules:: LDML Syntax Supported in MySQL This section describes how to add a UCA collation for a Unicode character set by writing the `' element within a `' character set description in the MySQL `Index.xml' file. The procedure described here does not require recompiling MySQL. It uses a subset of the Locale Data Markup Language (LDML) specification, which is available at `http://www.unicode.org/reports/tr35/'. In 5.1, this method of adding collations is supported as of MySQL 5.1.20. With this method, you need not define the entire collation. Instead, you begin with an existing `base' collation and describe the new collation in terms of how it differs from the base collation. The following table lists the base collations of the Unicode character sets for which UCA collations can be defined. *MySQL Character Sets Available for User-Defined UCA Collations* Character Set Base Collation `utf8' `utf8_unicode_ci' `ucs2' `ucs2_unicode_ci' The following sections show how to add a collation that is defined using LDML syntax, and provide a summary of LDML rules supported in MySQL.  File: manual.info, Node: ldml-collation-example, Next: ldml-rules, Prev: adding-collation-unicode-uca, Up: adding-collation-unicode-uca 10.4.4.1 Defining a UCA Collation using LDML Syntax ................................................... To add a UCA collation for a Unicode character set without recompiling MySQL, use the following procedure. If you are unfamiliar with the LDML rules used to describe the collation's sort characteristics, see *Note ldml-rules::. The example adds a collation named `utf8_phone_ci' to the `utf8' character set. The collation is designed for a scenario involving a Web application for which users post their names and phone numbers. Phone numbers can be given in very different formats: +7-12345-67 +7-12-345-67 +7 12 345 67 +7 (12) 345 67 +71234567 The problem raised by dealing with these kinds of values is that the varying permissible formats make searching for a specific phone number very difficult. The solution is to define a new collation that reorders punctuation characters, making them ignorable. 1. Choose a collation ID, as shown in *Note adding-collation-choosing-id::. The following steps use an ID of 252. 2. To modify the `Index.xml' configuration file. This file will be located in the directory named by the `character_sets_dir' system variable. You can check the variable value as follows, although the path name might be different on your system: mysql> SHOW VARIABLES LIKE 'character_sets_dir'; +--------------------+-----------------------------------------+ | Variable_name | Value | +--------------------+-----------------------------------------+ | character_sets_dir | /user/local/mysql/share/mysql/charsets/ | +--------------------+-----------------------------------------+ 3. Choose a name for the collation and list it in the `Index.xml' file. In addition, you'll need to provide the collation ordering rules. Find the `' element for the character set to which the collation is being added, and add a `' element that indicates the collation name and ID, to associate the name with the ID. Within the `' element, provide a `' element containing the ordering rules: ... \u0000 \u0020 \u0028 \u0029 \u002B \u002D ... 4. If you want a similar collation for other Unicode character sets, add other `' elements. For example, to define `ucs2_phone_ci', add a `' element to the `' element. Remember that each collation must have its own unique ID. 5. Restart the server and use this statement to verify that the collation is present: mysql> SHOW COLLATION LIKE 'utf8_phone_ci'; +---------------+---------+-----+---------+----------+---------+ | Collation | Charset | Id | Default | Compiled | Sortlen | +---------------+---------+-----+---------+----------+---------+ | utf8_phone_ci | utf8 | 252 | | | 8 | +---------------+---------+-----+---------+----------+---------+ Now test the collation to make sure that it has the desired properties. Create a table containing some sample phone numbers using the new collation: mysql> CREATE TABLE phonebook ( -> name VARCHAR(64), -> phone VARCHAR(64) CHARACTER SET utf8 COLLATE utf8_phone_ci -> ); Query OK, 0 rows affected (0.09 sec) mysql> INSERT INTO phonebook VALUES ('Svoj','+7 912 800 80 02'); Query OK, 1 row affected (0.00 sec) mysql> INSERT INTO phonebook VALUES ('Hf','+7 (912) 800 80 04'); Query OK, 1 row affected (0.00 sec) mysql> INSERT INTO phonebook VALUES ('Bar','+7-912-800-80-01'); Query OK, 1 row affected (0.00 sec) mysql> INSERT INTO phonebook VALUES ('Ramil','(7912) 800 80 03'); Query OK, 1 row affected (0.00 sec) mysql> INSERT INTO phonebook VALUES ('Sanja','+380 (912) 8008005'); Query OK, 1 row affected (0.00 sec) Run some queries to see whether the ignored punctuation characters are in fact ignored for sorting and comparisons: mysql> SELECT * FROM phonebook ORDER BY phone; +-------+--------------------+ | name | phone | +-------+--------------------+ | Sanja | +380 (912) 8008005 | | Bar | +7-912-800-80-01 | | Svoj | +7 912 800 80 02 | | Ramil | (7912) 800 80 03 | | Hf | +7 (912) 800 80 04 | +-------+--------------------+ 5 rows in set (0.00 sec) mysql> SELECT * FROM phonebook WHERE phone='+7(912)800-80-01'; +------+------------------+ | name | phone | +------+------------------+ | Bar | +7-912-800-80-01 | +------+------------------+ 1 row in set (0.00 sec) mysql> SELECT * FROM phonebook WHERE phone='79128008001'; +------+------------------+ | name | phone | +------+------------------+ | Bar | +7-912-800-80-01 | +------+------------------+ 1 row in set (0.00 sec) mysql> SELECT * FROM phonebook WHERE phone='7 9 1 2 8 0 0 8 0 0 1'; +------+------------------+ | name | phone | +------+------------------+ | Bar | +7-912-800-80-01 | +------+------------------+ 1 row in set (0.00 sec)  File: manual.info, Node: ldml-rules, Prev: ldml-collation-example, Up: adding-collation-unicode-uca 10.4.4.2 LDML Syntax Supported in MySQL ....................................... This section describes the LDML syntax that MySQL recognizes. This is a subset of the syntax described in the LDML specification available at `http://www.unicode.org/reports/tr35/', which should be consulted for further information. The rules described here are all supported except that character sorting occurs only at the primary level. Rules that specify differences at secondary or higher sort levels are recognized (and thus can be included in collation definitions) but are treated as equality at the primary level. *Character Representation* Characters named in LDML rules can be written in `\uNNNN' format, where NNNN is the hexadecimal Unicode code point value. Within hexadecimal values, the digits `A' through `F' are not case sensitive; `\u00E1' and `\u00e1' are equivalent. Basic Latin letters `A-Z' and `a-z' can also be written literally (this is a MySQL limitation; the LDML specification permits literal non-Latin1 characters in the rules). Only characters in the Basic Multilingual Plane can be specified. This notation does not apply to characters outside the BMP range of `0000' to `FFFF'. The `Index.xml' file itself should be written using ASCII encoding. *Syntax Rules* LDML has reset rules and shift rules to specify character ordering. Orderings are given as a set of rules that begin with a reset rule that establishes an anchor point, followed by shift rules that indicate how characters sort relative to the anchor point. * A `' rule does not specify any ordering in and of itself. Instead, it `resets' the ordering for subsequent shift rules to cause them to be taken in relation to a given character. Either of the following rules resets subsequent shift rules to be taken in relation to the letter `'A'': A \u0041 * The `

', `', and `' shift rules define primary, secondary, and tertiary differences of a character from another character: * Use primary differences to distinguish separate letters. * Use secondary differences to distinguish accent variations. * Use tertiary differences to distinguish lettercase variations. Either of these rules specifies a primary shift rule for the `'G'' character:

G

\u0047

 File: manual.info, Node: charset-configuration, Next: time-zone-support, Prev: adding-collation, Up: globalization 10.5 Character Set Configuration ================================ You can change the default server character set and collation with the `--character-set-server' and `--collation-server' options when you start the server. The collation must be a legal collation for the default character set. (Use the *Note `SHOW COLLATION': show-collation. statement to determine which collations are available for each character set.) See *Note server-options::. If you try to use a character set that is not compiled into your binary, you might run into the following problems: * Your program uses an incorrect path to determine where the character sets are stored (which is typically the `share/mysql/charsets' or `share/charsets' directory under the MySQL installation directory). This can be fixed by using the `--character-sets-dir' option when you run the program in question. For example, to specify a directory to be used by MySQL client programs, list it in the `[client]' group of your option file. The examples given here show what the setting might look like for Unix or Windows, respectively: [client] character-sets-dir=/usr/local/mysql/share/mysql/charsets [client] character-sets-dir="C:/Program Files/MySQL/MySQL Server 5.1/share/charsets" * The character set is a complex character set that cannot be loaded dynamically. In this case, you must recompile the program with support for the character set. For Unicode character sets, you can define collations without recompiling by using LDML notation. See *Note adding-collation-unicode-uca::. * The character set is a dynamic character set, but you do not have a configuration file for it. In this case, you should install the configuration file for the character set from a new MySQL distribution. * If your character set index file does not contain the name for the character set, your program displays an error message. The file is named `Index.xml' and the message is: Character set 'CHARSET_NAME' is not a compiled character set and is not specified in the '/usr/share/mysql/charsets/Index.xml' file To solve this problem, you should either get a new index file or manually add the name of any missing character sets to the current file. You can force client programs to use specific character set as follows: [client] default-character-set=CHARSET_NAME This is normally unnecessary. However, when `character_set_system' differs from `character_set_server' or `character_set_client', and you input characters manually (as database object identifiers, column values, or both), these may be displayed incorrectly in output from the client or the output itself may be formatted incorrectly. In such cases, starting the mysql client with `--default-character-set=SYSTEM_CHARACTER_SET'--that is, setting the client character set to match the system character set--should fix the problem. For `MyISAM' tables, you can check the character set name and number for a table with *Note `myisamchk -dvv TBL_NAME': myisamchk.  File: manual.info, Node: time-zone-support, Next: locale-support, Prev: charset-configuration, Up: globalization 10.6 MySQL Server Time Zone Support =================================== * Menu: * time-zone-upgrades:: Staying Current with Time Zone Changes * time-zone-leap-seconds:: Time Zone Leap Second Support The MySQL server maintains several time zone settings: * The system time zone. When the server starts, it attempts to determine the time zone of the host machine and uses it to set the `system_time_zone' system variable. The value does not change thereafter. You can set the system time zone for MySQL Server at startup with the `--timezone=TIMEZONE_NAME' option to *Note `mysqld_safe': mysqld-safe. You can also set it by setting the `TZ' environment variable before you start *Note `mysqld': mysqld. The permissible values for `--timezone' or `TZ' are system dependent. Consult your operating system documentation to see what values are acceptable. * The server's current time zone. The global `time_zone' system variable indicates the time zone the server currently is operating in. The initial value for `time_zone' is `'SYSTEM'', which indicates that the server time zone is the same as the system time zone. The initial global server time zone value can be specified explicitly at startup with the `--default-time-zone=TIMEZONE' option on the command line, or you can use the following line in an option file: default-time-zone='TIMEZONE' If you have the `SUPER' privilege, you can set the global server time zone value at runtime with this statement: mysql> SET GLOBAL time_zone = TIMEZONE; * Per-connection time zones. Each client that connects has its own time zone setting, given by the session `time_zone' variable. Initially, the session variable takes its value from the global `time_zone' variable, but the client can change its own time zone with this statement: mysql> SET time_zone = TIMEZONE; The current session time zone setting affects display and storage of time values that are zone-sensitive. This includes the values displayed by functions such as `NOW()' or `CURTIME()', and values stored in and retrieved from *Note `TIMESTAMP': datetime. columns. Values for *Note `TIMESTAMP': datetime. columns are converted from the current time zone to UTC for storage, and from UTC to the current time zone for retrieval. The current time zone setting does not affect values displayed by functions such as `UTC_TIMESTAMP()' or values in *Note `DATE': datetime, *Note `TIME': time, or *Note `DATETIME': datetime. columns. Nor are values in those data types stored in UTC; the time zone applies for them only when converting from `TIMESTAMP' values. If you want locale-specific arithmetic for *Note `DATE': datetime, *Note `TIME': time, or *Note `DATETIME': datetime. values, convert them to UTC, perform the arithmetic, and then convert back. The current values of the global and client-specific time zones can be retrieved like this: mysql> SELECT @@global.time_zone, @@session.time_zone; TIMEZONE values can be given in several formats, none of which are case sensitive: * The value `'SYSTEM'' indicates that the time zone should be the same as the system time zone. * The value can be given as a string indicating an offset from UTC, such as `'+10:00'' or `'-6:00''. * The value can be given as a named time zone, such as `'Europe/Helsinki'', `'US/Eastern'', or `'MET''. Named time zones can be used only if the time zone information tables in the `mysql' database have been created and populated. The MySQL installation procedure creates the time zone tables in the `mysql' database, but does not load them. You must do so manually using the following instructions. (If you are upgrading to MySQL 4.1.3 or later from an earlier version, you can create the tables by upgrading your `mysql' database. Use the instructions in *Note mysql-upgrade::. After creating the tables, you can load them.) *Note*: Loading the time zone information is not necessarily a one-time operation because the information changes occasionally. For example, the rules for Daylight Saving Time in the United States, Mexico, and parts of Canada changed in 2007. When such changes occur, applications that use the old rules become out of date and you may find it necessary to reload the time zone tables to keep the information used by your MySQL server current. See the notes at the end of this section. If your system has its own _zoneinfo_ database (the set of files describing time zones), you should use the *Note `mysql_tzinfo_to_sql': mysql-tzinfo-to-sql. program for filling the time zone tables. Examples of such systems are Linux, FreeBSD, Solaris, and Mac OS X. One likely location for these files is the `/usr/share/zoneinfo' directory. If your system does not have a zoneinfo database, you can use the downloadable package described later in this section. The *Note `mysql_tzinfo_to_sql': mysql-tzinfo-to-sql. program is used to load the time zone tables. On the command line, pass the zoneinfo directory path name to *Note `mysql_tzinfo_to_sql': mysql-tzinfo-to-sql. and send the output into the *Note `mysql': mysql. program. For example: shell> mysql_tzinfo_to_sql /usr/share/zoneinfo | mysql -u root mysql *Note `mysql_tzinfo_to_sql': mysql-tzinfo-to-sql. reads your system's time zone files and generates SQL statements from them. *Note `mysql': mysql. processes those statements to load the time zone tables. *Note `mysql_tzinfo_to_sql': mysql-tzinfo-to-sql. also can be used to load a single time zone file or to generate leap second information: * To load a single time zone file TZ_FILE that corresponds to a time zone name TZ_NAME, invoke *Note `mysql_tzinfo_to_sql': mysql-tzinfo-to-sql. like this: shell> mysql_tzinfo_to_sql TZ_FILE TZ_NAME | mysql -u root mysql With this approach, you must execute a separate command to load the time zone file for each named zone that the server needs to know about. * If your time zone needs to account for leap seconds, initialize the leap second information like this, where TZ_FILE is the name of your time zone file: shell> mysql_tzinfo_to_sql --leap TZ_FILE | mysql -u root mysql * After running *Note `mysql_tzinfo_to_sql': mysql-tzinfo-to-sql, it is best to restart the server so that it does not continue to use any previously cached time zone data. If your system is one that has no zoneinfo database (for example, Windows or HP-UX), you can use the package of pre-built time zone tables that is available for download at the MySQL Developer Zone: `http://dev.mysql.com/downloads/timezones.html' This time zone package contains `.frm', `.MYD', and `.MYI' files for the `MyISAM' time zone tables. These tables should be part of the `mysql' database, so you should place the files in the `mysql' subdirectory of your MySQL server's data directory. The server should be stopped while you do this and restarted afterward. *Warning*: Do not use the downloadable package if your system has a zoneinfo database. Use the *Note `mysql_tzinfo_to_sql': mysql-tzinfo-to-sql. utility instead. Otherwise, you may cause a difference in datetime handling between MySQL and other applications on your system. For information about time zone settings in replication setup, please see *Note replication-features::.  File: manual.info, Node: time-zone-upgrades, Next: time-zone-leap-seconds, Prev: time-zone-support, Up: time-zone-support 10.6.1 Staying Current with Time Zone Changes --------------------------------------------- As mentioned earlier, when the time zone rules change, applications that use the old rules become out of date. To stay current, it is necessary to make sure that your system uses current time zone information is used. For MySQL, there are two factors to consider in staying current: * The operating system time affects the value that the MySQL server uses for times if its time zone is set to `SYSTEM'. Make sure that your operating system is using the latest time zone information. For most operating systems, the latest update or service pack prepares your system for the time changes. Check the Web site for your operating system vendor for an update that addresses the time changes. * If you replace the system's `/etc/localtime' timezone file with a version that uses rules differing from those in effect at *Note `mysqld': mysqld. startup, you should restart *Note `mysqld': mysqld. so that it uses the updated rules. Otherwise, *Note `mysqld': mysqld. might not notice when the system changes its time. * If you use named time zones with MySQL, make sure that the time zone tables in the `mysql' database are up to date. If your system has its own zoneinfo database, you should reload the MySQL time zone tables whenever the zoneinfo database is updated, using the instructions given earlier in this section. For systems that do not have their own zoneinfo database, check the MySQL Developer Zone for updates. When a new update is available, download it and use it to replace your current time zone tables. *Note `mysqld': mysqld. caches time zone information that it looks up, so after replacing the time zone tables, you should restart *Note `mysqld': mysqld. to make sure that it does not continue to serve outdated time zone data. If you are uncertain whether named time zones are available, for use either as the server's time zone setting or by clients that set their own time zone, check whether your time zone tables are empty. The following query determines whether the table that contains time zone names has any rows: mysql> SELECT COUNT(*) FROM mysql.time_zone_name; +----------+ | COUNT(*) | +----------+ | 0 | +----------+ A count of zero indicates that the table is empty. In this case, no one can be using named time zones, and you don't need to update the tables. A count greater than zero indicates that the table is not empty and that its contents are available to be used for named time zone support. In this case, you should be sure to reload your time zone tables so that anyone who uses named time zones will get correct query results. To check whether your MySQL installation is updated properly for a change in Daylight Saving Time rules, use a test like the one following. The example uses values that are appropriate for the 2007 DST 1-hour change that occurs in the United States on March 11 at 2 a.m. The test uses these two queries: SELECT CONVERT_TZ('2007-03-11 2:00:00','US/Eastern','US/Central'); SELECT CONVERT_TZ('2007-03-11 3:00:00','US/Eastern','US/Central'); The two time values indicate the times at which the DST change occurs, and the use of named time zones requires that the time zone tables be used. The desired result is that both queries return the same result (the input time, converted to the equivalent value in the 'US/Central' time zone). Before updating the time zone tables, you would see an incorrect result like this: mysql> SELECT CONVERT_TZ('2007-03-11 2:00:00','US/Eastern','US/Central'); +------------------------------------------------------------+ | CONVERT_TZ('2007-03-11 2:00:00','US/Eastern','US/Central') | +------------------------------------------------------------+ | 2007-03-11 01:00:00 | +------------------------------------------------------------+ mysql> SELECT CONVERT_TZ('2007-03-11 3:00:00','US/Eastern','US/Central'); +------------------------------------------------------------+ | CONVERT_TZ('2007-03-11 3:00:00','US/Eastern','US/Central') | +------------------------------------------------------------+ | 2007-03-11 02:00:00 | +------------------------------------------------------------+ After updating the tables, you should see the correct result: mysql> SELECT CONVERT_TZ('2007-03-11 2:00:00','US/Eastern','US/Central'); +------------------------------------------------------------+ | CONVERT_TZ('2007-03-11 2:00:00','US/Eastern','US/Central') | +------------------------------------------------------------+ | 2007-03-11 01:00:00 | +------------------------------------------------------------+ mysql> SELECT CONVERT_TZ('2007-03-11 3:00:00','US/Eastern','US/Central'); +------------------------------------------------------------+ | CONVERT_TZ('2007-03-11 3:00:00','US/Eastern','US/Central') | +------------------------------------------------------------+ | 2007-03-11 01:00:00 | +------------------------------------------------------------+  File: manual.info, Node: time-zone-leap-seconds, Prev: time-zone-upgrades, Up: time-zone-support 10.6.2 Time Zone Leap Second Support ------------------------------------ Before MySQL 5.1.31, if the operating system is configured to return leap seconds from OS time calls or if the MySQL server uses a time zone definition that has leap seconds, functions such as `NOW()' could return a value having a time part that ends with `:59:60' or `:59:61'. If such values are inserted into a table, they would be dumped as is by *Note `mysqldump': mysqldump. but considered invalid when reloaded, leading to backup/restore problems. As of MySQL 5.1.31, leap second values are returned with a time part that ends with `:59:59'. This means that a function such as `NOW()' can return the same value for two or three consecutive seconds during the leap second. It remains true that literal temporal values having a time part that ends with `:59:60' or `:59:61' are considered invalid. If it is necessary to search for *Note `TIMESTAMP': datetime. values one second before the leap second, anomalous results may be obtained if you use a comparison with `'YYYY-MM-DD hh:mm:ss'' values: mysql> CREATE TABLE t1 (a INT, ts TIMESTAMP DEFAULT NOW(), PRIMARY KEY (ts)); Query OK, 0 rows affected (0.11 sec) mysql> # Simulate NOW() = '2009-01-01 02:59:59' mysql> SET timestamp = 1230768022; Query OK, 0 rows affected (0.00 sec) mysql> INSERT INTO t1 (a) VALUES (1); Query OK, 1 row affected (0.07 sec) mysql> # Simulate NOW() = '2009-01-01 02:59:60' mysql> SET timestamp = 1230768023; Query OK, 0 rows affected (0.00 sec) mysql> INSERT INTO t1 (a) VALUES (2); Query OK, 1 row affected (0.02 sec) mysql> SELECT * FROM t1; +------+---------------------+ | a | ts | +------+---------------------+ | 1 | 2008-12-31 18:00:22 | | 2 | 2008-12-31 18:00:23 | +------+---------------------+ 2 rows in set (0.02 sec) mysql> SELECT * FROM t1 WHERE ts = '2009-01-01 02:59:59'; Empty set (0.03 sec) To work around this, you can use a comparison based on the UTC value actually stored in column, which has the leap second correction applied: mysql> SELECT * FROM t1 WHERE UNIX_TIMESTAMP(ts) = 1230768023; +------+---------------------+ | a | ts | +------+---------------------+ | 2 | 2008-12-31 18:00:23 | +------+---------------------+ 1 row in set (0.02 sec)  File: manual.info, Node: locale-support, Prev: time-zone-support, Up: globalization 10.7 MySQL Server Locale Support ================================ Beginning with MySQL 5.1.12, the locale indicated by the `lc_time_names' system variable controls the language used to display day and month names and abbreviations. This variable affects the output from the `DATE_FORMAT()', `DAYNAME()', and `MONTHNAME()' functions. Locale names have language and region subtags listed by IANA (`http://www.iana.org/assignments/language-subtag-registry') such as `'ja_JP'' or `'pt_BR''. The default value is `'en_US'' regardless of your system's locale setting, but you can set the value at server startup or set the `GLOBAL' value if you have the `SUPER' privilege. Any client can examine the value of `lc_time_names' or set its `SESSION' value to affect the locale for its own connection. mysql> SET NAMES 'utf8'; Query OK, 0 rows affected (0.09 sec) mysql> SELECT @@lc_time_names; +-----------------+ | @@lc_time_names | +-----------------+ | en_US | +-----------------+ 1 row in set (0.00 sec) mysql> SELECT DAYNAME('2010-01-01'), MONTHNAME('2010-01-01'); +-----------------------+-------------------------+ | DAYNAME('2010-01-01') | MONTHNAME('2010-01-01') | +-----------------------+-------------------------+ | Friday | January | +-----------------------+-------------------------+ 1 row in set (0.00 sec) mysql> SELECT DATE_FORMAT('2010-01-01','%W %a %M %b'); +-----------------------------------------+ | DATE_FORMAT('2010-01-01','%W %a %M %b') | +-----------------------------------------+ | Friday Fri January Jan | +-----------------------------------------+ 1 row in set (0.00 sec) mysql> SET lc_time_names = 'es_MX'; Query OK, 0 rows affected (0.00 sec) mysql> SELECT @@lc_time_names; +-----------------+ | @@lc_time_names | +-----------------+ | es_MX | +-----------------+ 1 row in set (0.00 sec) mysql> SELECT DAYNAME('2010-01-01'), MONTHNAME('2010-01-01'); +-----------------------+-------------------------+ | DAYNAME('2010-01-01') | MONTHNAME('2010-01-01') | +-----------------------+-------------------------+ | viernes | enero | +-----------------------+-------------------------+ 1 row in set (0.00 sec) mysql> SELECT DATE_FORMAT('2010-01-01','%W %a %M %b'); +-----------------------------------------+ | DATE_FORMAT('2010-01-01','%W %a %M %b') | +-----------------------------------------+ | viernes vie enero ene | +-----------------------------------------+ 1 row in set (0.00 sec) The day or month name for each of the affected functions is converted from `utf8' to the character set indicated by the `character_set_connection' system variable. `lc_time_names' may be set to any of the following locale values. `ar_AE': Arabic - United Arab `ar_BH': Arabic - Bahrain Emirates `ar_DZ': Arabic - Algeria `ar_EG': Arabic - Egypt `ar_IN': Arabic - India `ar_IQ': Arabic - Iraq `ar_JO': Arabic - Jordan `ar_KW': Arabic - Kuwait `ar_LB': Arabic - Lebanon `ar_LY': Arabic - Libya `ar_MA': Arabic - Morocco `ar_OM': Arabic - Oman `ar_QA': Arabic - Qatar `ar_SA': Arabic - Saudi Arabia `ar_SD': Arabic - Sudan `ar_SY': Arabic - Syria `ar_TN': Arabic - Tunisia `ar_YE': Arabic - Yemen `be_BY': Belarusian - Belarus `bg_BG': Bulgarian - Bulgaria `ca_ES': Catalan - Spain `cs_CZ': Czech - Czech Republic `da_DK': Danish - Denmark `de_AT': German - Austria `de_BE': German - Belgium `de_CH': German - Switzerland `de_DE': German - Germany `de_LU': German - Luxembourg `EE': Estonian - Estonia `en_AU': English - Australia `en_CA': English - Canada `en_GB': English - United Kingdom `en_IN': English - India `en_NZ': English - New Zealand `en_PH': English - Philippines `en_US': English - United States `en_ZA': English - South Africa `en_ZW': English - Zimbabwe `es_AR': Spanish - Argentina `es_BO': Spanish - Bolivia `es_CL': Spanish - Chile `es_CO': Spanish - Columbia `es_CR': Spanish - Costa Rica `es_DO': Spanish - Dominican Republic `es_EC': Spanish - Ecuador `es_ES': Spanish - Spain `es_GT': Spanish - Guatemala `es_HN': Spanish - Honduras `es_MX': Spanish - Mexico `es_NI': Spanish - Nicaragua `es_PA': Spanish - Panama `es_PE': Spanish - Peru `es_PR': Spanish - Puerto Rico `es_PY': Spanish - Paraguay `es_SV': Spanish - El Salvador `es_US': Spanish - United States `es_UY': Spanish - Uruguay `es_VE': Spanish - Venezuela `eu_ES': Basque - Basque `fi_FI': Finnish - Finland `fo_FO': Faroese - Faroe Islands `fr_BE': French - Belgium `fr_CA': French - Canada `fr_CH': French - Switzerland `fr_FR': French - France `fr_LU': French - Luxembourg `gl_ES': Galician - Spain `gu_IN': Gujarati - India `he_IL': Hebrew - Israel `hi_IN': Hindi - India `hr_HR': Croatian - Croatia `hu_HU': Hungarian - Hungary `id_ID': Indonesian - Indonesia `is_IS': Icelandic - Iceland `it_CH': Italian - Switzerland `it_IT': Italian - Italy `ja_JP': Japanese - Japan `ko_KR': Korean - Republic of Korea `lt_LT': Lithuanian - Lithuania `lv_LV': Latvian - Latvia `mk_MK': Macedonian - FYROM `mn_MN': Mongolia - Mongolian `ms_MY': Malay - Malaysia `nb_NO': Norwegian(Bokmaal) - Norway `nl_BE': Dutch - Belgium `nl_NL': Dutch - The Netherlands `no_NO': Norwegian - Norway `pl_PL': Polish - Poland `pt_BR': Portugese - Brazil `pt_PT': Portugese - Portugal `ro_RO': Romanian - Romania `ru_RU': Russian - Russia `ru_UA': Russian - Ukraine `sk_SK': Slovak - Slovakia `sl_SI': Slovenian - Slovenia `sq_AL': Albanian - Albania `sr_YU': Serbian - Yugoslavia `sv_FI': Swedish - Finland `sv_SE': Swedish - Sweden `ta_IN': Tamil - India `te_IN': Telugu - India `th_TH': Thai - Thailand `tr_TR': Turkish - Turkey `uk_UA': Ukrainian - Ukraine `ur_PK': Urdu - Pakistan `vi_VN': Vietnamese - Viet Nam `zh_CN': Chinese - China `zh_HK': Chinese - Hong Kong `zh_TW': Chinese - Taiwan Province of China `lc_time_names' currently does not affect the `STR_TO_DATE()' or `GET_FORMAT()' function.  File: manual.info, Node: data-types, Next: functions, Prev: globalization, Up: Top 11 Data Types ************* * Menu: * data-type-overview:: Data Type Overview * numeric-types:: Numeric Types * date-and-time-types:: Date and Time Types * string-types:: String Types * storage-requirements:: Data Type Storage Requirements * out-of-range-and-overflow:: Out-of-Range and Overflow Handling * choosing-types:: Choosing the Right Type for a Column * other-vendor-data-types:: Using Data Types from Other Database Engines MySQL supports a number of data types in several categories: numeric types, date and time types, and string (character) types. This chapter first gives an overview of these data types, and then provides a more detailed description of the properties of the types in each category, and a summary of the data type storage requirements. The initial overview is intentionally brief. The more detailed descriptions later in the chapter should be consulted for additional information about particular data types, such as the permissible formats in which you can specify values. MySQL also supports extensions for handing spatial data. *Note spatial-extensions::, provides information about these data types. Data type descriptions use these conventions: * M indicates the maximum display width for integer types. For floating-point and fixed-point types, M is the total number of digits that can be stored. For string types, M is the maximum length. The maximum permissible value of M depends on the data type. * D applies to floating-point and fixed-point types and indicates the number of digits following the decimal point. The maximum possible value is 30, but should be no greater than M-2. * Square brackets (``['' and ``]'') indicate optional parts of type definitions.  File: manual.info, Node: data-type-overview, Next: numeric-types, Prev: data-types, Up: data-types 11.1 Data Type Overview ======================= * Menu: * numeric-type-overview:: Overview of Numeric Types * date-and-time-type-overview:: Overview of Date and Time Types * string-type-overview:: Overview of String Types * data-type-defaults:: Data Type Default Values  File: manual.info, Node: numeric-type-overview, Next: date-and-time-type-overview, Prev: data-type-overview, Up: data-type-overview 11.1.1 Overview of Numeric Types -------------------------------- A summary of the numeric data types follows. For additional information about properties of the numeric types, see *Note numeric-types::. Storage requirements are given in *Note storage-requirements::. M indicates the maximum display width for integer types. The maximum legal display width is 255. Display width is unrelated to the range of values a type can contain, as described in *Note numeric-types::. For floating-point and fixed-point types, M is the total number of digits that can be stored. If you specify `ZEROFILL' for a numeric column, MySQL automatically adds the `UNSIGNED' attribute to the column. Numeric data types that permit the `UNSIGNED' attribute also permit `SIGNED'. However, these data types are signed by default, so the `SIGNED' attribute has no effect. `SERIAL' is an alias for `BIGINT UNSIGNED NOT NULL AUTO_INCREMENT UNIQUE'. `SERIAL DEFAULT VALUE' in the definition of an integer column is an alias for `NOT NULL AUTO_INCREMENT UNIQUE'. *Warning*: When you use subtraction between integer values where one is of type `UNSIGNED', the result is unsigned unless the `NO_UNSIGNED_SUBTRACTION' SQL mode is enabled. See *Note cast-functions::. * `BIT[(M)]' A bit-field type. M indicates the number of bits per value, from 1 to 64. The default is 1 if M is omitted. * `TINYINT[(M)] [UNSIGNED] [ZEROFILL]' A very small integer. The signed range is `-128' to `127'. The unsigned range is `0' to `255'. * *Note `BOOL': numeric-types, *Note `BOOLEAN': numeric-types. These types are synonyms for *Note `TINYINT(1)': numeric-types. A value of zero is considered false. Nonzero values are considered true: mysql> SELECT IF(0, 'true', 'false'); +------------------------+ | IF(0, 'true', 'false') | +------------------------+ | false | +------------------------+ mysql> SELECT IF(1, 'true', 'false'); +------------------------+ | IF(1, 'true', 'false') | +------------------------+ | true | +------------------------+ mysql> SELECT IF(2, 'true', 'false'); +------------------------+ | IF(2, 'true', 'false') | +------------------------+ | true | +------------------------+ However, the values `TRUE' and `FALSE' are merely aliases for `1' and `0', respectively, as shown here: mysql> SELECT IF(0 = FALSE, 'true', 'false'); +--------------------------------+ | IF(0 = FALSE, 'true', 'false') | +--------------------------------+ | true | +--------------------------------+ mysql> SELECT IF(1 = TRUE, 'true', 'false'); +-------------------------------+ | IF(1 = TRUE, 'true', 'false') | +-------------------------------+ | true | +-------------------------------+ mysql> SELECT IF(2 = TRUE, 'true', 'false'); +-------------------------------+ | IF(2 = TRUE, 'true', 'false') | +-------------------------------+ | false | +-------------------------------+ mysql> SELECT IF(2 = FALSE, 'true', 'false'); +--------------------------------+ | IF(2 = FALSE, 'true', 'false') | +--------------------------------+ | false | +--------------------------------+ The last two statements display the results shown because `2' is equal to neither `1' nor `0'. * `SMALLINT[(M)] [UNSIGNED] [ZEROFILL]' A small integer. The signed range is `-32768' to `32767'. The unsigned range is `0' to `65535'. * `MEDIUMINT[(M)] [UNSIGNED] [ZEROFILL]' A medium-sized integer. The signed range is `-8388608' to `8388607'. The unsigned range is `0' to `16777215'. * `INT[(M)] [UNSIGNED] [ZEROFILL]' A normal-size integer. The signed range is `-2147483648' to `2147483647'. The unsigned range is `0' to `4294967295'. * `INTEGER[(M)] [UNSIGNED] [ZEROFILL]' This type is a synonym for *Note `INT': numeric-types. * `BIGINT[(M)] [UNSIGNED] [ZEROFILL]' A large integer. The signed range is `-9223372036854775808' to `9223372036854775807'. The unsigned range is `0' to `18446744073709551615'. `SERIAL' is an alias for `BIGINT UNSIGNED NOT NULL AUTO_INCREMENT UNIQUE'. Some things you should be aware of with respect to *Note `BIGINT': numeric-types. columns: * All arithmetic is done using signed *Note `BIGINT': numeric-types. or *Note `DOUBLE': numeric-types. values, so you should not use unsigned big integers larger than `9223372036854775807' (63 bits) except with bit functions! If you do that, some of the last digits in the result may be wrong because of rounding errors when converting a *Note `BIGINT': numeric-types. value to a *Note `DOUBLE': numeric-types. MySQL can handle *Note `BIGINT': numeric-types. in the following cases: * When using integers to store large unsigned values in a *Note `BIGINT': numeric-types. column. * In `MIN(COL_NAME)' or `MAX(COL_NAME)', where COL_NAME refers to a *Note `BIGINT': numeric-types. column. * When using operators (`+', `-', `*', and so on) where both operands are integers. * You can always store an exact integer value in a *Note `BIGINT': numeric-types. column by storing it using a string. In this case, MySQL performs a string-to-number conversion that involves no intermediate double-precision representation. * The `-', `+', and `*' operators use *Note `BIGINT': numeric-types. arithmetic when both operands are integer values. This means that if you multiply two big integers (or results from functions that return integers), you may get unexpected results when the result is larger than `9223372036854775807'. * `FLOAT[(M,D)] [UNSIGNED] [ZEROFILL]' A small (single-precision) floating-point number. Permissible values are `-3.402823466E+38' to `-1.175494351E-38', `0', and `1.175494351E-38' to `3.402823466E+38'. These are the theoretical limits, based on the IEEE standard. The actual range might be slightly smaller depending on your hardware or operating system. M is the total number of digits and D is the number of digits following the decimal point. If M and D are omitted, values are stored to the limits permitted by the hardware. A single-precision floating-point number is accurate to approximately 7 decimal places. `UNSIGNED', if specified, disallows negative values. Using *Note `FLOAT': numeric-types. might give you some unexpected problems because all calculations in MySQL are done with double precision. See *Note no-matching-rows::. * `DOUBLE[(M,D)] [UNSIGNED] [ZEROFILL]' A normal-size (double-precision) floating-point number. Permissible values are `-1.7976931348623157E+308' to `-2.2250738585072014E-308', `0', and `2.2250738585072014E-308' to `1.7976931348623157E+308'. These are the theoretical limits, based on the IEEE standard. The actual range might be slightly smaller depending on your hardware or operating system. M is the total number of digits and D is the number of digits following the decimal point. If M and D are omitted, values are stored to the limits permitted by the hardware. A double-precision floating-point number is accurate to approximately 15 decimal places. `UNSIGNED', if specified, disallows negative values. * `DOUBLE PRECISION[(M,D)] [UNSIGNED] [ZEROFILL]', `REAL[(M,D)] [UNSIGNED] [ZEROFILL]' These types are synonyms for *Note `DOUBLE': numeric-types. Exception: If the `REAL_AS_FLOAT' SQL mode is enabled, *Note `REAL': numeric-types. is a synonym for *Note `FLOAT': numeric-types. rather than *Note `DOUBLE': numeric-types. * `FLOAT(P) [UNSIGNED] [ZEROFILL]' A floating-point number. P represents the precision in bits, but MySQL uses this value only to determine whether to use *Note `FLOAT': numeric-types. or *Note `DOUBLE': numeric-types. for the resulting data type. If P is from 0 to 24, the data type becomes *Note `FLOAT': numeric-types. with no M or D values. If P is from 25 to 53, the data type becomes *Note `DOUBLE': numeric-types. with no M or D values. The range of the resulting column is the same as for the single-precision *Note `FLOAT': numeric-types. or double-precision *Note `DOUBLE': numeric-types. data types described earlier in this section. `FLOAT(P)' syntax is provided for ODBC compatibility. * `DECIMAL[(M[,D])] [UNSIGNED] [ZEROFILL]' A packed `exact' fixed-point number. M is the total number of digits (the precision) and D is the number of digits after the decimal point (the scale). The decimal point and (for negative numbers) the ``-'' sign are not counted in M. If D is 0, values have no decimal point or fractional part. The maximum number of digits (M) for *Note `DECIMAL': numeric-types. is 65. The maximum number of supported decimals (D) is 30. If D is omitted, the default is 0. If M is omitted, the default is 10. `UNSIGNED', if specified, disallows negative values. All basic calculations (`+, -, *, /') with *Note `DECIMAL': numeric-types. columns are done with a precision of 65 digits. * `DEC[(M[,D])] [UNSIGNED] [ZEROFILL]', `NUMERIC[(M[,D])] [UNSIGNED] [ZEROFILL]', `FIXED[(M[,D])] [UNSIGNED] [ZEROFILL]' These types are synonyms for *Note `DECIMAL': numeric-types. The *Note `FIXED': numeric-types. synonym is available for compatibility with other database systems.  File: manual.info, Node: date-and-time-type-overview, Next: string-type-overview, Prev: numeric-type-overview, Up: data-type-overview 11.1.2 Overview of Date and Time Types -------------------------------------- A summary of the temporal data types follows. For additional information about properties of the temporal types, see *Note date-and-time-types::. Storage requirements are given in *Note storage-requirements::. Functions that operate on temporal values are described at *Note date-and-time-functions::. For the *Note `DATETIME': datetime. and *Note `DATE': datetime. range descriptions, `supported' means that although earlier values might work, there is no guarantee. * *Note `DATE': datetime. A date. The supported range is `'1000-01-01'' to `'9999-12-31''. MySQL displays *Note `DATE': datetime. values in `'YYYY-MM-DD'' format, but permits assignment of values to *Note `DATE': datetime. columns using either strings or numbers. * *Note `DATETIME': datetime. A date and time combination. The supported range is `'1000-01-01 00:00:00'' to `'9999-12-31 23:59:59''. MySQL displays *Note `DATETIME': datetime. values in `'YYYY-MM-DD HH:MM:SS'' format, but permits assignment of values to *Note `DATETIME': datetime. columns using either strings or numbers. * *Note `TIMESTAMP': datetime. A timestamp. The range is `'1970-01-01 00:00:01'' UTC to `'2038-01-19 03:14:07'' UTC. *Note `TIMESTAMP': datetime. values are stored as the number of seconds since the epoch (`'1970-01-01 00:00:00'' UTC). A *Note `TIMESTAMP': datetime. cannot represent the value `'1970-01-01 00:00:00'' because that is equivalent to 0 seconds from the epoch and the value 0 is reserved for representing `'0000-00-00 00:00:00'', the `zero' *Note `TIMESTAMP': datetime. value. A *Note `TIMESTAMP': datetime. column is useful for recording the date and time of an *Note `INSERT': insert. or *Note `UPDATE': update. operation. By default, the first *Note `TIMESTAMP': datetime. column in a table is automatically set to the date and time of the most recent operation if you do not assign it a value yourself. You can also set any *Note `TIMESTAMP': datetime. column to the current date and time by assigning it a `NULL' value. Variations on automatic initialization and update properties are described in *Note timestamp::. A *Note `TIMESTAMP': datetime. value is returned as a string in the format `'YYYY-MM-DD HH:MM:SS'' with a display width fixed at 19 characters. To obtain the value as a number, you should add `+0' to the timestamp column. *Note*: The *Note `TIMESTAMP': datetime. format that was used prior to MySQL 4.1 is not supported in MySQL 5.1; see `MySQL 3.23, 4.0, 4.1 Reference Manual' for information regarding the old format. * *Note `TIME': time. A time. The range is `'-838:59:59'' to `'838:59:59''. MySQL displays *Note `TIME': time. values in `'HH:MM:SS'' format, but permits assignment of values to *Note `TIME': time. columns using either strings or numbers. * `YEAR[(2|4)]' A year in two-digit or four-digit format. The default is four-digit format. In four-digit format, the permissible values are `1901' to `2155', and `0000'. In two-digit format, the permissible values are `70' to `69', representing years from 1970 to 2069. MySQL displays *Note `YEAR': year. values in `YYYY' format, but permits assignment of values to *Note `YEAR': year. columns using either strings or numbers. The `SUM()' and `AVG()' aggregate functions do not work with temporal values. (They convert the values to numbers, which loses the part after the first nonnumeric character.) To work around this problem, you can convert to numeric units, perform the aggregate operation, and convert back to a temporal value. Examples: SELECT SEC_TO_TIME(SUM(TIME_TO_SEC(TIME_COL))) FROM TBL_NAME; SELECT FROM_DAYS(SUM(TO_DAYS(DATE_COL))) FROM TBL_NAME;  File: manual.info, Node: string-type-overview, Next: data-type-defaults, Prev: date-and-time-type-overview, Up: data-type-overview 11.1.3 Overview of String Types ------------------------------- A summary of the string data types follows. For additional information about properties of the string types, see *Note string-types::. Storage requirements are given in *Note storage-requirements::. In some cases, MySQL may change a string column to a type different from that given in a *Note `CREATE TABLE': create-table. or *Note `ALTER TABLE': alter-table. statement. See *Note silent-column-changes::. MySQL interprets length specifications in character column definitions in character units. This applies to *Note `CHAR': char, *Note `VARCHAR': char, and the *Note `TEXT': blob. types. Column definitions for many string data types can include attributes that specify the character set or collation of the column. These attributes apply to the *Note `CHAR': char, *Note `VARCHAR': char, the *Note `TEXT': blob. types, *Note `ENUM': enum, and *Note `SET': set. data types: * The `CHARACTER SET' attribute specifies the character set, and the `COLLATE' attribute specifies a collation for the character set. For example: CREATE TABLE t ( c1 VARCHAR(20) CHARACTER SET utf8, c2 TEXT CHARACTER SET latin1 COLLATE latin1_general_cs ); This table definition creates a column named `c1' that has a character set of `utf8' with the default collation for that character set, and a column named `c2' that has a character set of `latin1' and a case-sensitive collation. The rules for assigning the character set and collation when either or both of the `CHARACTER SET' and `COLLATE' attributes are missing are described in *Note charset-column::. `CHARSET' is a synonym for `CHARACTER SET'. * Specifying the `CHARACTER SET binary' attribute for a character data type causes the column to be created as the corresponding binary data type: *Note `CHAR': char. becomes *Note `BINARY': binary-varbinary, *Note `VARCHAR': char. becomes *Note `VARBINARY': binary-varbinary, and *Note `TEXT': blob. becomes *Note `BLOB': blob. For the *Note `ENUM': enum. and *Note `SET': set. data types, this does not occur; they are created as declared. Suppose that you specify a table using this definition: CREATE TABLE t ( c1 VARCHAR(10) CHARACTER SET binary, c2 TEXT CHARACTER SET binary, c3 ENUM('a','b','c') CHARACTER SET binary ); The resulting table has this definition: CREATE TABLE t ( c1 VARBINARY(10), c2 BLOB, c3 ENUM('a','b','c') CHARACTER SET binary ); * The `ASCII' attribute is shorthand for `CHARACTER SET latin1'. * The `UNICODE' attribute is shorthand for `CHARACTER SET ucs2'. * The `BINARY' attribute is shorthand for specifying the binary collation of the column character set. In this case, sorting and comparison are based on numeric character values. Character column sorting and comparison are based on the character set assigned to the column. For the *Note `CHAR': char, *Note `VARCHAR': char, *Note `TEXT': blob, *Note `ENUM': enum, and *Note `SET': set. data types, you can declare a column with a binary collation or the `BINARY' attribute to cause sorting and comparison to use the underlying character code values rather than a lexical ordering. *Note charset::, provides additional information about use of character sets in MySQL. * `[NATIONAL] CHAR[(M)] [CHARACTER SET CHARSET_NAME] [COLLATE COLLATION_NAME]' A fixed-length string that is always right-padded with spaces to the specified length when stored. M represents the column length in characters. The range of M is 0 to 255. If M is omitted, the length is 1. *Note*: Trailing spaces are removed when *Note `CHAR': char. values are retrieved unless the `PAD_CHAR_TO_FULL_LENGTH' SQL mode is enabled. *Note `CHAR': char. is shorthand for *Note `CHARACTER': char. *Note `NATIONAL CHAR': char. (or its equivalent short form, *Note `NCHAR': char.) is the standard SQL way to define that a *Note `CHAR': char. column should use some predefined character set. MySQL 4.1 and up uses `utf8' as this predefined character set. *Note charset-national::. The *Note `CHAR BYTE': binary-varbinary. data type is an alias for the *Note `BINARY': binary-varbinary. data type. This is a compatibility feature. MySQL permits you to create a column of type `CHAR(0)'. This is useful primarily when you have to be compliant with old applications that depend on the existence of a column but that do not actually use its value. `CHAR(0)' is also quite nice when you need a column that can take only two values: A column that is defined as `CHAR(0) NULL' occupies only one bit and can take only the values `NULL' and `''' (the empty string). * `[NATIONAL] VARCHAR(M) [CHARACTER SET CHARSET_NAME] [COLLATE COLLATION_NAME]' A variable-length string. M represents the maximum column length in characters. The range of M is 0 to 65,535. The effective maximum length of a *Note `VARCHAR': char. is subject to the maximum row size (65,535 bytes, which is shared among all columns) and the character set used. For example, `utf8' characters can require up to three bytes per character, so a *Note `VARCHAR': char. column that uses the `utf8' character set can be declared to be a maximum of 21,844 characters. See *Note column-count-limit::. MySQL stores *Note `VARCHAR': char. values as a one-byte or two-byte length prefix plus data. The length prefix indicates the number of bytes in the value. A *Note `VARCHAR': char. column uses one length byte if values require no more than 255 bytes, two length bytes if values may require more than 255 bytes. *Note*: MySQL 5.1 follows the standard SQL specification, and does _not_ remove trailing spaces from *Note `VARCHAR': char. values. *Note `VARCHAR': char. is shorthand for *Note `CHARACTER VARYING': char. *Note `NATIONAL VARCHAR': char. is the standard SQL way to define that a *Note `VARCHAR': char. column should use some predefined character set. MySQL 4.1 and up uses `utf8' as this predefined character set. *Note charset-national::. *Note `NVARCHAR': char. is shorthand for *Note `NATIONAL VARCHAR': char. * `BINARY(M)' The *Note `BINARY': binary-varbinary. type is similar to the *Note `CHAR': char. type, but stores binary byte strings rather than nonbinary character strings. M represents the column length in bytes. * `VARBINARY(M)' The *Note `VARBINARY': binary-varbinary. type is similar to the *Note `VARCHAR': char. type, but stores binary byte strings rather than nonbinary character strings. M represents the maximum column length in bytes. * *Note `TINYBLOB': blob. A *Note `BLOB': blob. column with a maximum length of 255 (2^8 - 1) bytes. Each *Note `TINYBLOB': blob. value is stored using a one-byte length prefix that indicates the number of bytes in the value. * `TINYTEXT [CHARACTER SET CHARSET_NAME] [COLLATE COLLATION_NAME]' A *Note `TEXT': blob. column with a maximum length of 255 (2^8 - 1) characters. The effective maximum length is less if the value contains multi-byte characters. Each *Note `TINYTEXT': blob. value is stored using a one-byte length prefix that indicates the number of bytes in the value. * `BLOB[(M)]' A *Note `BLOB': blob. column with a maximum length of 65,535 (2^16 - 1) bytes. Each *Note `BLOB': blob. value is stored using a two-byte length prefix that indicates the number of bytes in the value. An optional length M can be given for this type. If this is done, MySQL creates the column as the smallest *Note `BLOB': blob. type large enough to hold values M bytes long. * `TEXT[(M)] [CHARACTER SET CHARSET_NAME] [COLLATE COLLATION_NAME]' A *Note `TEXT': blob. column with a maximum length of 65,535 (2^16 - 1) characters. The effective maximum length is less if the value contains multi-byte characters. Each *Note `TEXT': blob. value is stored using a two-byte length prefix that indicates the number of bytes in the value. An optional length M can be given for this type. If this is done, MySQL creates the column as the smallest *Note `TEXT': blob. type large enough to hold values M characters long. * *Note `MEDIUMBLOB': blob. A *Note `BLOB': blob. column with a maximum length of 16,777,215 (2^24 - 1) bytes. Each *Note `MEDIUMBLOB': blob. value is stored using a three-byte length prefix that indicates the number of bytes in the value. * `MEDIUMTEXT [CHARACTER SET CHARSET_NAME] [COLLATE COLLATION_NAME]' A *Note `TEXT': blob. column with a maximum length of 16,777,215 (2^24 - 1) characters. The effective maximum length is less if the value contains multi-byte characters. Each *Note `MEDIUMTEXT': blob. value is stored using a three-byte length prefix that indicates the number of bytes in the value. * *Note `LONGBLOB': blob. A *Note `BLOB': blob. column with a maximum length of 4,294,967,295 or 4GB (2^32 - 1) bytes. The effective maximum length of *Note `LONGBLOB': blob. columns depends on the configured maximum packet size in the client/server protocol and available memory. Each *Note `LONGBLOB': blob. value is stored using a four-byte length prefix that indicates the number of bytes in the value. * `LONGTEXT [CHARACTER SET CHARSET_NAME] [COLLATE COLLATION_NAME]' A *Note `TEXT': blob. column with a maximum length of 4,294,967,295 or 4GB (2^32 - 1) characters. The effective maximum length is less if the value contains multi-byte characters. The effective maximum length of *Note `LONGTEXT': blob. columns also depends on the configured maximum packet size in the client/server protocol and available memory. Each *Note `LONGTEXT': blob. value is stored using a four-byte length prefix that indicates the number of bytes in the value. * `ENUM('VALUE1','VALUE2',...) [CHARACTER SET CHARSET_NAME] [COLLATE COLLATION_NAME]' An enumeration. A string object that can have only one value, chosen from the list of values `'VALUE1'', `'VALUE2'', `...', `NULL' or the special `''' error value. An *Note `ENUM': enum. column can have a maximum of 65,535 distinct values. *Note `ENUM': enum. values are represented internally as integers. * `SET('VALUE1','VALUE2',...) [CHARACTER SET CHARSET_NAME] [COLLATE COLLATION_NAME]' A set. A string object that can have zero or more values, each of which must be chosen from the list of values `'VALUE1'', `'VALUE2'', `...' A *Note `SET': set. column can have a maximum of 64 members. *Note `SET': set. values are represented internally as integers.  File: manual.info, Node: data-type-defaults, Prev: string-type-overview, Up: data-type-overview 11.1.4 Data Type Default Values ------------------------------- The `DEFAULT VALUE' clause in a data type specification indicates a default value for a column. With one exception, the default value must be a constant; it cannot be a function or an expression. This means, for example, that you cannot set the default for a date column to be the value of a function such as `NOW()' or `CURRENT_DATE'. The exception is that you can specify `CURRENT_TIMESTAMP' as the default for a *Note `TIMESTAMP': datetime. column. See *Note timestamp::. *Note `BLOB': blob. and *Note `TEXT': blob. columns cannot be assigned a default value. If a column definition includes no explicit `DEFAULT' value, MySQL determines the default value as follows: If the column can take `NULL' as a value, the column is defined with an explicit `DEFAULT NULL' clause. If the column cannot take `NULL' as the value, MySQL defines the column with no explicit `DEFAULT' clause. Exception: If the column is defined as part of a `PRIMARY KEY' but not explicitly as `NOT NULL', MySQL creates it as a `NOT NULL' column (because `PRIMARY KEY' columns must be `NOT NULL'), but also assigns it a `DEFAULT' clause using the implicit default value. To prevent this, include an explicit `NOT NULL' in the definition of any `PRIMARY KEY' column. For data entry for a `NOT NULL' column that has no explicit `DEFAULT' clause, if an *Note `INSERT': insert. or *Note `REPLACE': replace. statement includes no value for the column, or an *Note `UPDATE': update. statement sets the column to `NULL', MySQL handles the column according to the SQL mode in effect at the time: * If strict SQL mode is not enabled, MySQL sets the column to the implicit default value for the column data type. * If strict mode is enabled, an error occurs for transactional tables and the statement is rolled back. For nontransactional tables, an error occurs, but if this happens for the second or subsequent row of a multiple-row statement, the preceding rows will have been inserted. Suppose that a table `t' is defined as follows: CREATE TABLE t (i INT NOT NULL); In this case, `i' has no explicit default, so in strict mode each of the following statements produce an error and no row is inserted. When not using strict mode, only the third statement produces an error; the implicit default is inserted for the first two statements, but the third fails because `DEFAULT(i)' cannot produce a value: INSERT INTO t VALUES(); INSERT INTO t VALUES(DEFAULT); INSERT INTO t VALUES(DEFAULT(i)); See *Note server-sql-mode::. For a given table, you can use the *Note `SHOW CREATE TABLE': show-create-table. statement to see which columns have an explicit `DEFAULT' clause. Implicit defaults are defined as follows: * For numeric types, the default is `0', with the exception that for integer or floating-point types declared with the `AUTO_INCREMENT' attribute, the default is the next value in the sequence. * For date and time types other than *Note `TIMESTAMP': datetime, the default is the appropriate `zero' value for the type. For the first *Note `TIMESTAMP': datetime. column in a table, the default value is the current date and time. See *Note date-and-time-types::. * For string types other than *Note `ENUM': enum, the default value is the empty string. For *Note `ENUM': enum, the default is the first enumeration value. `SERIAL DEFAULT VALUE' in the definition of an integer column is an alias for `NOT NULL AUTO_INCREMENT UNIQUE'.  File: manual.info, Node: numeric-types, Next: date-and-time-types, Prev: data-type-overview, Up: data-types 11.2 Numeric Types ================== MySQL supports all the standard SQL numeric data types. These types include the exact numeric data types (*Note `INTEGER': numeric-types, *Note `SMALLINT': numeric-types, *Note `DECIMAL': numeric-types, and *Note `NUMERIC': numeric-types.), as well as the approximate numeric data types (*Note `FLOAT': numeric-types, *Note `REAL': numeric-types, and *Note `DOUBLE PRECISION': numeric-types.). The keyword *Note `INT': numeric-types. is a synonym for *Note `INTEGER': numeric-types, and the keywords *Note `DEC': numeric-types. and `FIXED' are synonyms for *Note `DECIMAL': numeric-types. MySQL treats *Note `DOUBLE': numeric-types. as a synonym for *Note `DOUBLE PRECISION': numeric-types. (a nonstandard extension). MySQL also treats *Note `REAL': numeric-types. as a synonym for *Note `DOUBLE PRECISION': numeric-types. (a nonstandard variation), unless the `REAL_AS_FLOAT' SQL mode is enabled. The *Note `BIT': numeric-types. data type stores bit-field values and is supported for `MyISAM', `MEMORY', `InnoDB', and *Note `NDBCLUSTER': mysql-cluster. tables. For information about numeric type storage requirements, see *Note storage-requirements::. The data type used for the result of a calculation on numeric operands depends on the types of the operands and the operations performed on them. For more information, see *Note arithmetic-functions::. For information about how MySQL handles assignment of out-of-range values to columns and overflow during expression evaluation, see *Note out-of-range-and-overflow::. * Integer Types * MySQL supports the SQL standard integer types *Note `INTEGER': numeric-types. (or *Note `INT': numeric-types.) and *Note `SMALLINT': numeric-types. As an extension to the standard, MySQL also supports the integer types *Note `TINYINT': numeric-types, *Note `MEDIUMINT': numeric-types, and *Note `BIGINT': numeric-types. The following table shows the required storage and range for each integer type. Type Storage Minimum Value Maximum Value (Bytes) (Signed/Unsigned) Signed/Unsigned) *Note 1 `-128' `127' `TINYINT': numeric-types. `0' `255' *Note 2 `-32768' `32767' `SMALLINT': numeric-types. `0' `65535' *Note 3 `-8388608' `8388607' `MEDIUMINT': numeric-types. `0' `16777215' *Note 4 `-2147483648' `2147483647' `INT': numeric-types. `0' `4294967295' *Note 8 `-9223372036854775808' `9223372036854775807' `BIGINT': numeric-types. `0' `18446744073709551615' * Floating-Point (Approximate-Value) Types * The *Note `FLOAT': numeric-types. and *Note `DOUBLE': numeric-types. types represent approximate numeric data values. MySQL uses four bytes for single-precision values and eight bytes for double-precision values. For *Note `FLOAT': numeric-types, the SQL standard permits an optional specification of the precision (but not the range of the exponent) in bits following the keyword *Note `FLOAT': numeric-types. in parentheses. MySQL also supports this optional precision specification, but the precision value is used only to determine storage size. A precision from 0 to 23 results in a four-byte single-precision *Note `FLOAT': numeric-types. column. A precision from 24 to 53 results in an eight-byte double-precision *Note `DOUBLE': numeric-types. column. MySQL permits a nonstandard syntax: `FLOAT(M,D)' or `REAL(M,D)' or `DOUBLE PRECISION(M,D)'. Here, ``(M,D)'' means than values can be stored with up to M digits in total, of which D digits may be after the decimal point. For example, a column defined as `FLOAT(7,4)' will look like `-999.9999' when displayed. MySQL performs rounding when storing values, so if you insert `999.00009' into a `FLOAT(7,4)' column, the approximate result is `999.0001'. Because floating-point values are approximate and not stored as exact values, attempts to treat them as exact in comparisons may lead to problems. They are also subject to platform or implementation dependencies. For more information, see *Note problems-with-float:: For maximum portability, code requiring storage of approximate numeric data values should use *Note `FLOAT': numeric-types. or *Note `DOUBLE PRECISION': numeric-types. with no specification of precision or number of digits. * Fixed-Point (Exact-Value) Types * The *Note `DECIMAL': numeric-types. and *Note `NUMERIC': numeric-types. types store exact numeric data values. These types are used when it is important to preserve exact precision, for example with monetary data. In MySQL, *Note `NUMERIC': numeric-types. is implemented as *Note `DECIMAL': numeric-types, so the following remarks about *Note `DECIMAL': numeric-types. apply equally to *Note `NUMERIC': numeric-types. MySQL 5.1 stores *Note `DECIMAL': numeric-types. values in binary format. Before MySQL 5.0.3, they were stored as strings. See *Note precision-math::. In a *Note `DECIMAL': numeric-types. column declaration, the precision and scale can be (and usually is) specified; for example: salary DECIMAL(5,2) In this example, `5' is the precision and `2' is the scale. The precision represents the number of significant digits that are stored for values, and the scale represents the number of digits that can be stored following the decimal point. Standard SQL requires that `DECIMAL(5,2)' be able to store any value with five digits and two decimals, so values that can be stored in the `salary' column range from `-999.99' to `999.99'. In standard SQL, the syntax `DECIMAL(M)' is equivalent to `DECIMAL(M,0)'. Similarly, the syntax *Note `DECIMAL': numeric-types. is equivalent to `DECIMAL(M,0)', where the implementation is permitted to decide the value of M. MySQL supports both of these variant forms of *Note `DECIMAL': numeric-types. syntax. The default value of M is 10. If the scale is 0, *Note `DECIMAL': numeric-types. values contain no decimal point or fractional part. The maximum number of digits for *Note `DECIMAL': numeric-types. is 65, but the actual range for a given *Note `DECIMAL': numeric-types. column can be constrained by the precision or scale for a given column. When such a column is assigned a value with more digits following the decimal point than are permitted by the specified scale, the value is converted to that scale. (The precise behavior is operating system-specific, but generally the effect is truncation to the permissible number of digits.) * Bit-Value Type * The *Note `BIT': numeric-types. data type is used to store bit-field values. A type of `BIT(M)' enables storage of M-bit values. M can range from 1 to 64. To specify bit values, `b'VALUE'' notation can be used. VALUE is a binary value written using zeros and ones. For example, `b'111'' and `b'10000000'' represent 7 and 128, respectively. See *Note bit-field-values::. If you assign a value to a `BIT(M)' column that is less than M bits long, the value is padded on the left with zeros. For example, assigning a value of `b'101'' to a `BIT(6)' column is, in effect, the same as assigning `b'000101''. * Numeric Type Attributes * MySQL supports an extension for optionally specifying the display width of integer data types in parentheses following the base keyword for the type. For example, *Note `INT(4)': numeric-types. specifies an *Note `INT': numeric-types. with a display width of four digits. This optional display width may be used by applications to display integer values having a width less than the width specified for the column by left-padding them with spaces. (That is, this width is present in the metadata returned with result sets. Whether it is used or not is up to the application.) The display width does _not_ constrain the range of values that can be stored in the column. Nor does it prevent values wider than the column display width from being displayed correctly. For example, a column specified as *Note `SMALLINT(3)': numeric-types. has the usual *Note `SMALLINT': numeric-types. range of `-32768' to `32767', and values outside the range permitted by three digits are displayed in full using more than three digits. When used in conjunction with the optional (nonstandard) attribute `ZEROFILL', the default padding of spaces is replaced with zeros. For example, for a column declared as *Note `INT(4) ZEROFILL': numeric-types, a value of `5' is retrieved as `0005'. *Note*: The `ZEROFILL' attribute is ignored when a column is involved in expressions or *Note `UNION': union. queries. If you store values larger than the display width in an integer column that has the `ZEROFILL' attribute, you may experience problems when MySQL generates temporary tables for some complicated joins. In these cases, MySQL assumes that the data values fit within the column display width. All integer types can have an optional (nonstandard) attribute `UNSIGNED'. Unsigned type can be used to permit only nonnegative numbers in a column or when you need a larger upper numeric range for the column. For example, if an *Note `INT': numeric-types. column is `UNSIGNED', the size of the column's range is the same but its endpoints shift from `-2147483648' and `2147483647' up to `0' and `4294967295'. Floating-point and fixed-point types also can be `UNSIGNED'. As with integer types, this attribute prevents negative values from being stored in the column. Unlike the integer types, the upper range of column values remains the same. If you specify `ZEROFILL' for a numeric column, MySQL automatically adds the `UNSIGNED' attribute to the column. Integer or floating-point data types can have the additional attribute `AUTO_INCREMENT'. When you insert a value of `NULL' (recommended) or `0' into an indexed `AUTO_INCREMENT' column, the column is set to the next sequence value. Typically this is `VALUE+1', where VALUE is the largest value for the column currently in the table. `AUTO_INCREMENT' sequences begin with `1'.  File: manual.info, Node: date-and-time-types, Next: string-types, Prev: numeric-types, Up: data-types 11.3 Date and Time Types ======================== * Menu: * datetime:: The `DATETIME', `DATE', and `TIMESTAMP' Types * time:: The `TIME' Type * year:: The `YEAR' Type * y2k-issues:: Year 2000 Issues and Date Types The date and time types for representing temporal values are *Note `DATETIME': datetime, *Note `DATE': datetime, *Note `TIMESTAMP': datetime, *Note `TIME': time, and *Note `YEAR': year. Each temporal type has a range of legal values, as well as a `zero' value that may be used when you specify an illegal value that MySQL cannot represent. The *Note `TIMESTAMP': datetime. type has special automatic updating behavior, described later on. For temporal type storage requirements, see *Note storage-requirements::. MySQL gives warnings or errors if you try to insert an illegal date. By setting the SQL mode to the appropriate value, you can specify more exactly what kind of dates you want MySQL to support. (See *Note server-sql-mode::.) You can get MySQL to accept certain dates, such as `'2009-11-31'', by using the `ALLOW_INVALID_DATES' SQL mode. This is useful when you want to store a `possibly wrong' value which the user has specified (for example, in a web form) in the database for future processing. Under this mode, MySQL verifies only that the month is in the range from 0 to 12 and that the day is in the range from 0 to 31. These ranges are defined to include zero because MySQL permits you to store dates where the day or month and day are zero in a *Note `DATE': datetime. or *Note `DATETIME': datetime. column. This is extremely useful for applications that need to store a birthdate for which you do not know the exact date. In this case, you simply store the date as `'2009-00-00'' or `'2009-01-00''. If you store dates such as these, you should not expect to get correct results for functions such as `DATE_SUB()' or `DATE_ADD()' that require complete dates. (If you do _not_ want to permit zero in dates, you can use the `NO_ZERO_IN_DATE' SQL mode). Prior to MySQL 5.1.18, when *Note `DATE': datetime. values are compared with *Note `DATETIME': datetime. values, the time portion of the *Note `DATETIME': datetime. value is ignored, or the comparison could be performed as a string compare. Starting from MySQL 5.1.18, a *Note `DATE': datetime. value is coerced to the *Note `DATETIME': datetime. type by adding the time portion as `'00:00:00''. To mimic the old behavior, use the `CAST()' function to cause the comparison operands to be treated as previously. For example: DATE_COL = CAST(NOW() AS DATE) MySQL also permits you to store `'0000-00-00'' as a `dummy date' (if you are not using the `NO_ZERO_DATE' SQL mode). This is in some cases more convenient (and uses less data and index space) than using `NULL' values. Here are some general considerations to keep in mind when working with date and time types: * MySQL retrieves values for a given date or time type in a standard output format, but it attempts to interpret a variety of formats for input values that you supply (for example, when you specify a value to be assigned to or compared to a date or time type). Only the formats described in the following sections are supported. It is expected that you supply legal values. Unpredictable results may occur if you use values in other formats. * Dates containing two-digit year values are ambiguous because the century is unknown. MySQL interprets two-digit year values using the following rules: * Year values in the range `70-99' are converted to `1970-1999'. * Year values in the range `00-69' are converted to `2000-2069'. * Although MySQL tries to interpret values in several formats, dates always must be given in year-month-day order (for example, `'98-09-04''), rather than in the month-day-year or day-month-year orders commonly used elsewhere (for example, `'09-04-98'', `'04-09-98''). * MySQL automatically converts a date or time type value to a number if the value is used in a numeric context and vice versa. * By default, when MySQL encounters a value for a date or time type that is out of range or otherwise illegal for the type (as described at the beginning of this section), it converts the value to the `zero' value for that type. The exception is that out-of-range *Note `TIME': time. values are clipped to the appropriate endpoint of the *Note `TIME': time. range. The following table shows the format of the `zero' value for each type. Note that the use of these values produces warnings if the `NO_ZERO_DATE' SQL mode is enabled. Data Type `Zero' Value *Note `DATETIME': `'0000-00-00 00:00:00'' datetime. *Note `DATE': `'0000-00-00'' datetime. *Note `TIMESTAMP': `'0000-00-00 00:00:00'' datetime. *Note `TIME': time. `'00:00:00'' *Note `YEAR': year. `0000' * The `zero' values are special, but you can store or refer to them explicitly using the values shown in the table. You can also do this using the values `'0'' or `0', which are easier to write. * `Zero' date or time values used through MyODBC are converted automatically to `NULL' in MyODBC 2.50.12 and above, because ODBC cannot handle such values.  File: manual.info, Node: datetime, Next: time, Prev: date-and-time-types, Up: date-and-time-types 11.3.1 The `DATETIME', `DATE', and `TIMESTAMP' Types ---------------------------------------------------- * Menu: * timestamp:: `TIMESTAMP' Properties The *Note `DATETIME': datetime, *Note `DATE': datetime, and *Note `TIMESTAMP': datetime. types are related. This section describes their characteristics, how they are similar, and how they differ. The *Note `DATETIME': datetime. type is used when you need values that contain both date and time information. MySQL retrieves and displays *Note `DATETIME': datetime. values in `'YYYY-MM-DD HH:MM:SS'' format. The supported range is `'1000-01-01 00:00:00'' to `'9999-12-31 23:59:59''. The *Note `DATE': datetime. type is used when you need only a date value, without a time part. MySQL retrieves and displays *Note `DATE': datetime. values in `'YYYY-MM-DD'' format. The supported range is `'1000-01-01'' to `'9999-12-31''. For the *Note `DATETIME': datetime. and *Note `DATE': datetime. range descriptions, `supported' means that although earlier values might work, there is no guarantee. The *Note `TIMESTAMP': datetime. data type has a range of `'1970-01-01 00:00:01'' UTC to `'2038-01-19 03:14:07'' UTC. It has varying properties, depending on the MySQL version and the SQL mode the server is running in. These properties are described later in this section. You can specify *Note `DATETIME': datetime, *Note `DATE': datetime, and *Note `TIMESTAMP': datetime. values using any of a common set of formats: * As a string in either `'YYYY-MM-DD HH:MM:SS'' or `'YY-MM-DD HH:MM:SS'' format. A `relaxed' syntax is permitted: Any punctuation character may be used as the delimiter between date parts or time parts. For example, `'98-12-31 11:30:45'', `'98.12.31 11+30+45'', `'98/12/31 11*30*45'', and `'98@12@31 11^30^45'' are equivalent. * As a string in either `'YYYY-MM-DD'' or `'YY-MM-DD'' format. A `relaxed' syntax is permitted here, too. For example, `'98-12-31'', `'98.12.31'', `'98/12/31'', and `'98@12@31'' are equivalent. * As a string with no delimiters in either `'YYYYMMDDHHMMSS'' or `'YYMMDDHHMMSS'' format, provided that the string makes sense as a date. For example, `'20070523091528'' and `'070523091528'' are interpreted as `'2007-05-23 09:15:28'', but `'071122129015'' is illegal (it has a nonsensical minute part) and becomes `'0000-00-00 00:00:00''. * As a string with no delimiters in either `'YYYYMMDD'' or `'YYMMDD'' format, provided that the string makes sense as a date. For example, `'20070523'' and `'070523'' are interpreted as `'2007-05-23'', but `'071332'' is illegal (it has nonsensical month and day parts) and becomes `'0000-00-00''. * As a number in either `YYYYMMDDHHMMSS' or `YYMMDDHHMMSS' format, provided that the number makes sense as a date. For example, `19830905132800' and `830905132800' are interpreted as `'1983-09-05 13:28:00''. * As a number in either `YYYYMMDD' or `YYMMDD' format, provided that the number makes sense as a date. For example, `19830905' and `830905' are interpreted as `'1983-09-05''. * As the result of a function that returns a value that is acceptable in a *Note `DATETIME': datetime, *Note `DATE': datetime, or *Note `TIMESTAMP': datetime. context, such as `NOW()' or `CURRENT_DATE'. A microseconds part is permissible in temporal values in some contexts, such as in literal values, and in the arguments to or return values from some temporal functions. Microseconds are specified as a trailing `.uuuuuu' part in the value. Example: mysql> SELECT MICROSECOND('2010-12-10 14:12:09.019473'); +-------------------------------------------+ | MICROSECOND('2010-12-10 14:12:09.019473') | +-------------------------------------------+ | 19473 | +-------------------------------------------+ However, microseconds cannot be stored into a column of any temporal data type. Any microseconds part is discarded. Conversion of *Note `TIME': time. or *Note `DATETIME': datetime. values to numeric form (for example, by adding `+0') results in a double value with a microseconds part of `.000000': mysql> SELECT CURTIME(), CURTIME()+0; +-----------+---------------+ | CURTIME() | CURTIME()+0 | +-----------+---------------+ | 10:41:36 | 104136.000000 | +-----------+---------------+ mysql> SELECT NOW(), NOW()+0; +---------------------+-----------------------+ | NOW() | NOW()+0 | +---------------------+-----------------------+ | 2007-11-30 10:41:47 | 20071130104147.000000 | +---------------------+-----------------------+ Illegal *Note `DATETIME': datetime, *Note `DATE': datetime, or *Note `TIMESTAMP': datetime. values are converted to the `zero' value of the appropriate type (`'0000-00-00 00:00:00'' or `'0000-00-00''). For values specified as strings that include date part delimiters, it is not necessary to specify two digits for month or day values that are less than `10'. `'1979-6-9'' is the same as `'1979-06-09''. Similarly, for values specified as strings that include time part delimiters, it is not necessary to specify two digits for hour, minute, or second values that are less than `10'. `'1979-10-30 1:2:3'' is the same as `'1979-10-30 01:02:03''. Values specified as numbers should be 6, 8, 12, or 14 digits long. If a number is 8 or 14 digits long, it is assumed to be in `YYYYMMDD' or `YYYYMMDDHHMMSS' format and that the year is given by the first 4 digits. If the number is 6 or 12 digits long, it is assumed to be in `YYMMDD' or `YYMMDDHHMMSS' format and that the year is given by the first 2 digits. Numbers that are not one of these lengths are interpreted as though padded with leading zeros to the closest length. Values specified as nondelimited strings are interpreted using their length as given. If the string is 8 or 14 characters long, the year is assumed to be given by the first 4 characters. Otherwise, the year is assumed to be given by the first 2 characters. The string is interpreted from left to right to find year, month, day, hour, minute, and second values, for as many parts as are present in the string. This means you should not use strings that have fewer than 6 characters. For example, if you specify `'9903'', thinking that represents March, 1999, MySQL inserts a `zero' date value into your table. This occurs because the year and month values are `99' and `03', but the day part is completely missing, so the value is not a legal date. However, you can explicitly specify a value of zero to represent missing month or day parts. For example, you can use `'990300'' to insert the value `'1999-03-00''. You can to some extent assign values of one date type to an object of a different date type. However, there may be some alteration of the value or loss of information: * If you assign a *Note `DATE': datetime. value to a *Note `DATETIME': datetime. or *Note `TIMESTAMP': datetime. object, the time part of the resulting value is set to `'00:00:00'' because the *Note `DATE': datetime. value contains no time information. * If you assign a *Note `DATETIME': datetime. or *Note `TIMESTAMP': datetime. value to a *Note `DATE': datetime. object, the time part of the resulting value is deleted because the *Note `DATE': datetime. type stores no time information. * Remember that although *Note `DATETIME': datetime, *Note `DATE': datetime, and *Note `TIMESTAMP': datetime. values all can be specified using the same set of formats, the types do not all have the same range of values. For example, *Note `TIMESTAMP': datetime. values cannot be earlier than `1970' UTC or later than `'2038-01-19 03:14:07'' UTC. This means that a date such as `'1968-01-01'', while legal as a *Note `DATETIME': datetime. or *Note `DATE': datetime. value, is not valid as a *Note `TIMESTAMP': datetime. value and is converted to `0'. Be aware of certain problems when specifying date values: * The relaxed format permitted for values specified as strings can be deceiving. For example, a value such as `'10:11:12'' might look like a time value because of the ``:'' delimiter, but if used in a date context is interpreted as the year `'2010-11-12''. The value `'10:45:15'' is converted to `'0000-00-00'' because `'45'' is not a legal month. * The server requires that month and day values be legal, and not merely in the range 1 to 12 and 1 to 31, respectively. With strict mode disabled, invalid dates such as `'2004-04-31'' are converted to `'0000-00-00'' and a warning is generated. With strict mode enabled, invalid dates generate an error. To permit such dates, enable `ALLOW_INVALID_DATES'. See *Note server-sql-mode::, for more information. * MySQL does not accept timestamp values that include a zero in the day or month column or values that are not a valid date. The sole exception to this rule is the special value `'0000-00-00 00:00:00''. * Dates containing two-digit year values are ambiguous because the century is unknown. MySQL interprets two-digit year values using the following rules: * Year values in the range `00-69' are converted to `2000-2069'. * Year values in the range `70-99' are converted to `1970-1999'.  File: manual.info, Node: timestamp, Prev: datetime, Up: datetime 11.3.1.1 `TIMESTAMP' Properties ............................... *Note `TIMESTAMP': datetime. columns are displayed in the same format as *Note `DATETIME': datetime. columns. In other words, the display width is fixed at 19 characters, and the format is `'YYYY-MM-DD HH:MM:SS''. *Note*: In older versions of MySQL (prior to 4.1), the properties of the *Note `TIMESTAMP': datetime. data type differed significantly in several ways from what is described in this section (see the `MySQL 3.23, 4.0, 4.1 Reference Manual' for details); these include syntax extensions which are deprecated in MySQL 5.1, and no longer supported in MySQL 5.5. This has implications for performing a dump and restore or replicating between MySQL Server versions. If you are using columns that are defined using the old *Note `TIMESTAMP(N)': datetime. syntax, see *Note upgrading-from-previous-series::, prior to upgrading to MySQL 5.1 or later. *Note `TIMESTAMP': datetime. values are converted from the current time zone to UTC for storage, and converted back from UTC to the current time zone for retrieval. (This occurs only for the *Note `TIMESTAMP': datetime. data type, not for other types such as *Note `DATETIME': datetime.) By default, the current time zone for each connection is the server's time. The time zone can be set on a per-connection basis, as described in *Note time-zone-support::. As long as the time zone setting remains constant, you get back the same value you store. If you store a *Note `TIMESTAMP': datetime. value, and then change the time zone and retrieve the value, the retrieved value is different from the value you stored. This occurs because the same time zone was not used for conversion in both directions. The current time zone is available as the value of the `time_zone' system variable. The *Note `TIMESTAMP': datetime. data type offers automatic initialization and updating. You can choose whether to use these properties and which column should have them: * For one *Note `TIMESTAMP': datetime. column in a table, you can assign the current timestamp as the default value and the auto-update value. It is possible to have the current timestamp be the default value for initializing the column, for the auto-update value, or both. It is not possible to have the current timestamp be the default value for one column and the auto-update value for another column. * Any single *Note `TIMESTAMP': datetime. column in a table can be used as the one that is initialized to the current date and time, or updated automatically. This need not be the first *Note `TIMESTAMP': datetime. column. * The auto-update *Note `TIMESTAMP': datetime. column, if there is one, is automatically updated to the current timestamp when the value of any other column in the row is changed from its current value. If all other columns are set to their current values, the *Note `TIMESTAMP': datetime. column does not change. Automatic updating does not apply if the *Note `TIMESTAMP': datetime. column is explicitly assigned a value other than `NULL'. * If a `DEFAULT' value is specified for the first *Note `TIMESTAMP': datetime. column in a table, it is not ignored. The default can be `CURRENT_TIMESTAMP' or a constant date and time value. * In a *Note `CREATE TABLE': create-table. statement, the first *Note `TIMESTAMP': datetime. column can be declared in any of the following ways: * With both `DEFAULT CURRENT_TIMESTAMP' and `ON UPDATE CURRENT_TIMESTAMP' clauses, the column has the current timestamp for its default value, and is automatically updated. * With neither `DEFAULT' nor `ON UPDATE' clauses, it is the same as `DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP'. * With a `DEFAULT CURRENT_TIMESTAMP' clause and no `ON UPDATE' clause, the column has the current timestamp for its default value but is not automatically updated. * With no `DEFAULT' clause and with an `ON UPDATE CURRENT_TIMESTAMP' clause, the column has a default of 0 and is automatically updated. * With a constant `DEFAULT' value, the column has the given default and is not automatically initialized to the current timestamp. If the column also has an `ON UPDATE CURRENT_TIMESTAMP' clause, it is automatically updated; otherwise, it has a constant default and is not automatically updated. In other words, you can use the current timestamp for both the initial value and the auto-update value, or either one, or neither. (For example, you can specify `ON UPDATE' to enable auto-update without also having the column auto-initialized.) The following column definitions demonstrate each possibility: * Auto-initialization and auto-update: ts TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP * Auto-initialization only: ts TIMESTAMP DEFAULT CURRENT_TIMESTAMP * Auto-update only: ts TIMESTAMP DEFAULT 0 ON UPDATE CURRENT_TIMESTAMP * Neither: ts TIMESTAMP DEFAULT 0 * To specify automatic default or updating for a *Note `TIMESTAMP': datetime. column other than the first one, you must suppress the automatic initialization and update behaviors for the first *Note `TIMESTAMP': datetime. column by explicitly assigning it a constant `DEFAULT' value (for example, `DEFAULT 0' or `DEFAULT '2003-01-01 00:00:00''). Then, for the other *Note `TIMESTAMP': datetime. column, the rules are the same as for the first *Note `TIMESTAMP': datetime. column, except that if you omit both of the `DEFAULT' and `ON UPDATE' clauses, no automatic initialization or updating occurs. Example: CREATE TABLE t ( ts1 TIMESTAMP DEFAULT 0, ts2 TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP); * `CURRENT_TIMESTAMP' or any of its synonyms (`CURRENT_TIMESTAMP()', `NOW()', `LOCALTIME', `LOCALTIME()', `LOCALTIMESTAMP', or `LOCALTIMESTAMP()') can be used in the `DEFAULT' and `ON UPDATE' clauses. They all mean `the current timestamp.' (`UTC_TIMESTAMP' is not permitted. Its range of values does not align with those of the *Note `TIMESTAMP': datetime. column anyway unless the current time zone is `UTC'.) * The order of the `DEFAULT' and `ON UPDATE' attributes does not matter. If both `DEFAULT' and `ON UPDATE' are specified for a *Note `TIMESTAMP': datetime. column, either can precede the other. For example, these statements are equivalent: CREATE TABLE t (ts TIMESTAMP); CREATE TABLE t (ts TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP); CREATE TABLE t (ts TIMESTAMP ON UPDATE CURRENT_TIMESTAMP DEFAULT CURRENT_TIMESTAMP); *Note*: The examples that use `DEFAULT 0' will not work if the `NO_ZERO_DATE' SQL mode is enabled because that mode causes `zero' date values (specified as `0', `'0000-00-00', or `'0000-00-00 00:00:00'') to be rejected. Be aware that the `TRADITIONAL' SQL mode includes `NO_ZERO_DATE'. *Note `TIMESTAMP': datetime. columns are `NOT NULL' by default, cannot contain `NULL' values, and assigning `NULL' assigns the current timestamp. However, a *Note `TIMESTAMP': datetime. column can be permitted to contain `NULL' by declaring it with the `NULL' attribute. In this case, the default value also becomes `NULL' unless overridden with a `DEFAULT' clause that specifies a different default value. `DEFAULT NULL' can be used to explicitly specify `NULL' as the default value. (For a *Note `TIMESTAMP': datetime. column not declared with the `NULL' attribute, `DEFAULT NULL' is illegal.) If a *Note `TIMESTAMP': datetime. column permits `NULL' values, assigning `NULL' sets it to `NULL', not to the current timestamp. The following table contains several *Note `TIMESTAMP': datetime. columns that permit `NULL' values: CREATE TABLE t ( ts1 TIMESTAMP NULL DEFAULT NULL, ts2 TIMESTAMP NULL DEFAULT 0, ts3 TIMESTAMP NULL DEFAULT CURRENT_TIMESTAMP ); Note that a *Note `TIMESTAMP': datetime. column that permits `NULL' values will _not_ take on the current timestamp except under one of the following conditions: * Its default value is defined as `CURRENT_TIMESTAMP' * `NOW()' or `CURRENT_TIMESTAMP' is inserted into the column In other words, a *Note `TIMESTAMP': datetime. column defined as `NULL' will auto-initialize only if it is created using a definition such as the following: CREATE TABLE t (ts TIMESTAMP NULL DEFAULT CURRENT_TIMESTAMP); Otherwise--that is, if the *Note `TIMESTAMP': datetime. column is defined to permit `NULL' values but not using `DEFAULT CURRENT_TIMESTAMP', as shown here... CREATE TABLE t1 (ts TIMESTAMP NULL DEFAULT NULL); CREATE TABLE t2 (ts TIMESTAMP NULL DEFAULT '0000-00-00 00:00:00'); ...then you must explicitly insert a value corresponding to the current date and time. For example: INSERT INTO t1 VALUES (NOW()); INSERT INTO t2 VALUES (CURRENT_TIMESTAMP); *Note*: The MySQL server can be run with the `MAXDB' SQL mode enabled. When the server runs with this mode enabled, *Note `TIMESTAMP': datetime. is identical with *Note `DATETIME': datetime. That is, if this mode is enabled at the time that a table is created, *Note `TIMESTAMP': datetime. columns are created as *Note `DATETIME': datetime. columns. As a result, such columns use *Note `DATETIME': datetime. display format, have the same range of values, and there is no automatic initialization or updating to the current date and time. To enable `MAXDB' mode, set the server SQL mode to `MAXDB' at startup using the `--sql-mode=MAXDB' server option or by setting the global `sql_mode' variable at runtime: mysql> SET GLOBAL sql_mode=MAXDB; A client can cause the server to run in `MAXDB' mode for its own connection as follows: mysql> SET SESSION sql_mode=MAXDB;  File: manual.info, Node: time, Next: year, Prev: datetime, Up: date-and-time-types 11.3.2 The `TIME' Type ---------------------- MySQL retrieves and displays *Note `TIME': time. values in `'HH:MM:SS'' format (or `'HHH:MM:SS'' format for large hours values). *Note `TIME': time. values may range from `'-838:59:59'' to `'838:59:59''. The hours part may be so large because the *Note `TIME': time. type can be used not only to represent a time of day (which must be less than 24 hours), but also elapsed time or a time interval between two events (which may be much greater than 24 hours, or even negative). You can specify *Note `TIME': time. values in a variety of formats: * As a string in `'D HH:MM:SS.fraction'' format. You can also use one of the following `relaxed' syntaxes: `'HH:MM:SS.fraction'', `'HH:MM:SS'', `'HH:MM'', `'D HH:MM:SS'', `'D HH:MM'', `'D HH'', or `'SS''. Here `D' represents days and can have a value from 0 to 34. Note that MySQL does not store the fraction part. * As a string with no delimiters in `'HHMMSS'' format, provided that it makes sense as a time. For example, `'101112'' is understood as `'10:11:12'', but `'109712'' is illegal (it has a nonsensical minute part) and becomes `'00:00:00''. * As a number in `HHMMSS' format, provided that it makes sense as a time. For example, `101112' is understood as `'10:11:12''. The following alternative formats are also understood: `SS', `MMSS', `HHMMSS', `HHMMSS.fraction'. Note that MySQL does not store the fraction part. * As the result of a function that returns a value that is acceptable in a *Note `TIME': time. context, such as `CURRENT_TIME'. A trailing `.uuuuuu' microseconds part of *Note `TIME': time. values is permitted under the same conditions as for other temporal values, as described in *Note datetime::. This includes the property that any microseconds part is discarded from values stored into *Note `TIME': time. columns. For *Note `TIME': time. values specified as strings that include a time part delimiter, it is not necessary to specify two digits for hours, minutes, or seconds values that are less than `10'. `'8:3:2'' is the same as `'08:03:02''. Be careful about assigning abbreviated values to a *Note `TIME': time. column. Without colons, MySQL interprets values using the assumption that the two rightmost digits represent seconds. (MySQL interprets *Note `TIME': time. values as elapsed time rather than as time of day.) For example, you might think of `'1112'' and `1112' as meaning `'11:12:00'' (12 minutes after 11 o'clock), but MySQL interprets them as `'00:11:12'' (11 minutes, 12 seconds). Similarly, `'12'' and `12' are interpreted as `'00:00:12''. *Note `TIME': time. values with colons, by contrast, are always treated as time of the day. That is, `'11:12'' mean `'11:12:00'', not `'00:11:12''. By default, values that lie outside the *Note `TIME': time. range but are otherwise legal are clipped to the closest endpoint of the range. For example, `'-850:00:00'' and `'850:00:00'' are converted to `'-838:59:59'' and `'838:59:59''. Illegal *Note `TIME': time. values are converted to `'00:00:00''. Note that because `'00:00:00'' is itself a legal *Note `TIME': time. value, there is no way to tell, from a value of `'00:00:00'' stored in a table, whether the original value was specified as `'00:00:00'' or whether it was illegal. For more restrictive treatment of invalid *Note `TIME': time. values, enable strict SQL mode to cause errors to occur. See *Note server-sql-mode::.  File: manual.info, Node: year, Next: y2k-issues, Prev: time, Up: date-and-time-types 11.3.3 The `YEAR' Type ---------------------- The *Note `YEAR': year. type is a one-byte type used for representing years. It can be declared as `YEAR(2)' or `YEAR(4)' to specify a display width of two or four characters. The default is four characters if no width is given. For four-digit format, MySQL displays *Note `YEAR': year. values in `YYYY' format, with a range of `1901' to `2155', or `0000'. For two-digit format, MySQL displays only the last two (least significant) digits; for example, `70' (1970 or 2070) or `69' (2069). You can specify input *Note `YEAR': year. values in a variety of formats: * As a four-digit string in the range `'1901'' to `'2155''. * As a four-digit number in the range `1901' to `2155'. * As a two-digit string in the range `'00'' to `'99''. Values in the ranges `'00'' to `'69'' and `'70'' to `'99'' are converted to *Note `YEAR': year. values in the ranges `2000' to `2069' and `1970' to `1999'. * As a two-digit number in the range `1' to `99'. Values in the ranges `1' to `69' and `70' to `99' are converted to *Note `YEAR': year. values in the ranges `2001' to `2069' and `1970' to `1999'. Note that the range for two-digit numbers is slightly different from the range for two-digit strings, because you cannot specify zero directly as a number and have it be interpreted as `2000'. You must specify it as a string `'0'' or `'00'' or it is interpreted as `0000'. * As the result of a function that returns a value that is acceptable in a *Note `YEAR': year. context, such as `NOW()'. Illegal *Note `YEAR': year. values are converted to `0000'.  File: manual.info, Node: y2k-issues, Prev: year, Up: date-and-time-types 11.3.4 Year 2000 Issues and Date Types -------------------------------------- MySQL Server itself has no problems with Year 2000 (Y2K) compliance: * MySQL Server uses Unix time functions that handle dates into the year `2038' for *Note `TIMESTAMP': datetime. values. For *Note `DATE': datetime. and *Note `DATETIME': datetime. values, dates through the year `9999' are accepted. * All MySQL date functions are implemented in one source file, `sql/time.cc', and are coded very carefully to be year 2000-safe. * In MySQL, the *Note `YEAR': year. data type can store the years `0' and `1901' to `2155' in one byte and display them using two or four digits. All two-digit years are considered to be in the range `1970' to `2069', which means that if you store `01' in a *Note `YEAR': year. column, MySQL Server treats it as `2001'. Although MySQL Server itself is Y2K-safe, you may run into problems if you use it with applications that are not Y2K-safe. For example, many old applications store or manipulate years using two-digit values (which are ambiguous) rather than four-digit values. This problem may be compounded by applications that use values such as `00' or `99' as `missing' value indicators. Unfortunately, these problems may be difficult to fix because different applications may be written by different programmers, each of whom may use a different set of conventions and date-handling functions. Thus, even though MySQL Server has no Y2K problems, _it is the application's responsibility to provide unambiguous input_. Any value containing a two-digit year is ambiguous, because the century is unknown. Such values must be interpreted into four-digit form because MySQL stores years internally using four digits. For *Note `DATETIME': datetime, *Note `DATE': datetime, *Note `TIMESTAMP': datetime, and *Note `YEAR': year. types, MySQL interprets dates with ambiguous year values using the following rules: * Year values in the range `00-69' are converted to `2000-2069'. * Year values in the range `70-99' are converted to `1970-1999'. Remember that these rules are only heuristics that provide reasonable guesses as to what your data values mean. If the rules used by MySQL do not produce the correct values, you should provide unambiguous input containing four-digit year values. `ORDER BY' properly sorts *Note `YEAR': year. values that have two-digit years. Some functions like `MIN()' and `MAX()' convert a *Note `YEAR': year. to a number. This means that a value with a two-digit year does not work properly with these functions. The fix in this case is to convert the *Note `TIMESTAMP': datetime. or *Note `YEAR': year. to four-digit year format.  File: manual.info, Node: string-types, Next: storage-requirements, Prev: date-and-time-types, Up: data-types 11.4 String Types ================= * Menu: * char:: The `CHAR' and `VARCHAR' Types * binary-varbinary:: The `BINARY' and `VARBINARY' Types * blob:: The `BLOB' and `TEXT' Types * enum:: The `ENUM' Type * set:: The `SET' Type The string types are *Note `CHAR': char, *Note `VARCHAR': char, *Note `BINARY': binary-varbinary, *Note `VARBINARY': binary-varbinary, *Note `BLOB': blob, *Note `TEXT': blob, *Note `ENUM': enum, and *Note `SET': set. This section describes how these types work and how to use them in your queries. For string type storage requirements, see *Note storage-requirements::.  File: manual.info, Node: char, Next: binary-varbinary, Prev: string-types, Up: string-types 11.4.1 The `CHAR' and `VARCHAR' Types ------------------------------------- The *Note `CHAR': char. and *Note `VARCHAR': char. types are similar, but differ in the way they are stored and retrieved. They also differ in maximum length and in whether trailing spaces are retained. The *Note `CHAR': char. and *Note `VARCHAR': char. types are declared with a length that indicates the maximum number of characters you want to store. For example, `CHAR(30)' can hold up to 30 characters. The length of a *Note `CHAR': char. column is fixed to the length that you declare when you create the table. The length can be any value from 0 to 255. When *Note `CHAR': char. values are stored, they are right-padded with spaces to the specified length. When *Note `CHAR': char. values are retrieved, trailing spaces are removed unless the `PAD_CHAR_TO_FULL_LENGTH' SQL mode is enabled. Values in *Note `VARCHAR': char. columns are variable-length strings. The length can be specified as a value from 0 to 65,535. The effective maximum length of a *Note `VARCHAR': char. is subject to the maximum row size (65,535 bytes, which is shared among all columns) and the character set used. See *Note column-count-limit::. In contrast to *Note `CHAR': char, *Note `VARCHAR': char. values are stored as a one-byte or two-byte length prefix plus data. The length prefix indicates the number of bytes in the value. A column uses one length byte if values require no more than 255 bytes, two length bytes if values may require more than 255 bytes. If strict SQL mode is not enabled and you assign a value to a *Note `CHAR': char. or *Note `VARCHAR': char. column that exceeds the column's maximum length, the value is truncated to fit and a warning is generated. For truncation of nonspace characters, you can cause an error to occur (rather than a warning) and suppress insertion of the value by using strict SQL mode. See *Note server-sql-mode::. For *Note `VARCHAR': char. columns, trailing spaces in excess of the column length are truncated prior to insertion and a warning is generated, regardless of the SQL mode in use. For *Note `CHAR': char. columns, truncation of excess trailing spaces from inserted values is performed silently regardless of the SQL mode. *Note `VARCHAR': char. values are not padded when they are stored. Trailing spaces are retained when values are stored and retrieved, in conformance with standard SQL. The following table illustrates the differences between *Note `CHAR': char. and *Note `VARCHAR': char. by showing the result of storing various string values into `CHAR(4)' and `VARCHAR(4)' columns (assuming that the column uses a single-byte character set such as `latin1'). Value `CHAR(4)' Storage `VARCHAR(4)'Storage Required Required `''' `' '' 4 bytes `''' 1 byte `'ab'' `'ab '' 4 bytes `'ab'' 3 bytes `'abcd'' `'abcd'' 4 bytes `'abcd'' 5 bytes `'abcdefgh''`'abcd'' 4 bytes `'abcd'' 5 bytes The values shown as stored in the last row of the table apply _only when not using strict mode_; if MySQL is running in strict mode, values that exceed the column length are _not stored_, and an error results. If a given value is stored into the `CHAR(4)' and `VARCHAR(4)' columns, the values retrieved from the columns are not always the same because trailing spaces are removed from *Note `CHAR': char. columns upon retrieval. The following example illustrates this difference: mysql> CREATE TABLE vc (v VARCHAR(4), c CHAR(4)); Query OK, 0 rows affected (0.01 sec) mysql> INSERT INTO vc VALUES ('ab ', 'ab '); Query OK, 1 row affected (0.00 sec) mysql> SELECT CONCAT('(', v, ')'), CONCAT('(', c, ')') FROM vc; +---------------------+---------------------+ | CONCAT('(', v, ')') | CONCAT('(', c, ')') | +---------------------+---------------------+ | (ab ) | (ab) | +---------------------+---------------------+ 1 row in set (0.06 sec) Values in *Note `CHAR': char. and *Note `VARCHAR': char. columns are sorted and compared according to the character set collation assigned to the column. All MySQL collations are of type `PADSPACE'. This means that all *Note `CHAR': char. and *Note `VARCHAR': char. values in MySQL are compared without regard to any trailing spaces. For example: mysql> CREATE TABLE names (myname CHAR(10), yourname VARCHAR(10)); Query OK, 0 rows affected (0.09 sec) mysql> INSERT INTO names VALUES ('Monty ', 'Monty '); Query OK, 1 row affected (0.00 sec) mysql> SELECT myname = 'Monty ', yourname = 'Monty ' FROM names; +--------------------+----------------------+ | myname = 'Monty ' | yourname = 'Monty ' | +--------------------+----------------------+ | 1 | 1 | +--------------------+----------------------+ 1 row in set (0.00 sec) This is true for all MySQL versions, and is not affected by the server SQL mode. *Note*: For more information about MySQL character sets and collations, see *Note charset::. For those cases where trailing pad characters are stripped or comparisons ignore them, if a column has an index that requires unique values, inserting into the column values that differ only in number of trailing pad characters will result in a duplicate-key error. For example, if a table contains `'a'', an attempt to store `'a '' causes a duplicate-key error.  File: manual.info, Node: binary-varbinary, Next: blob, Prev: char, Up: string-types 11.4.2 The `BINARY' and `VARBINARY' Types ----------------------------------------- The *Note `BINARY': binary-varbinary. and *Note `VARBINARY': binary-varbinary. types are similar to *Note `CHAR': char. and *Note `VARCHAR': char, except that they contain binary strings rather than nonbinary strings. That is, they contain byte strings rather than character strings. This means that they have no character set, and sorting and comparison are based on the numeric values of the bytes in the values. The permissible maximum length is the same for *Note `BINARY': binary-varbinary. and *Note `VARBINARY': binary-varbinary. as it is for *Note `CHAR': char. and *Note `VARCHAR': char, except that the length for *Note `BINARY': binary-varbinary. and *Note `VARBINARY': binary-varbinary. is a length in bytes rather than in characters. The *Note `BINARY': binary-varbinary. and *Note `VARBINARY': binary-varbinary. data types are distinct from the `CHAR BINARY' and `VARCHAR BINARY' data types. For the latter types, the `BINARY' attribute does not cause the column to be treated as a binary string column. Instead, it causes the binary collation for the column character set to be used, and the column itself contains nonbinary character strings rather than binary byte strings. For example, `CHAR(5) BINARY' is treated as `CHAR(5) CHARACTER SET latin1 COLLATE latin1_bin', assuming that the default character set is `latin1'. This differs from `BINARY(5)', which stores 5-bytes binary strings that have no character set or collation. For information about differences between nonbinary string binary collations and binary strings, see *Note charset-binary-collations::. If strict SQL mode is not enabled and you assign a value to a *Note `BINARY': binary-varbinary. or *Note `VARBINARY': binary-varbinary. column that exceeds the column's maximum length, the value is truncated to fit and a warning is generated. For cases of truncation, you can cause an error to occur (rather than a warning) and suppress insertion of the value by using strict SQL mode. See *Note server-sql-mode::. When *Note `BINARY': binary-varbinary. values are stored, they are right-padded with the pad value to the specified length. The pad value is `0x00' (the zero byte). Values are right-padded with `0x00' on insert, and no trailing bytes are removed on select. All bytes are significant in comparisons, including `ORDER BY' and `DISTINCT' operations. `0x00' bytes and spaces are different in comparisons, with `0x00' < space. Example: For a `BINARY(3)' column, `'a '' becomes `'a \0'' when inserted. `'a\0'' becomes `'a\0\0'' when inserted. Both inserted values remain unchanged when selected. For *Note `VARBINARY': binary-varbinary, there is no padding on insert and no bytes are stripped on select. All bytes are significant in comparisons, including `ORDER BY' and `DISTINCT' operations. `0x00' bytes and spaces are different in comparisons, with `0x00' < space. For those cases where trailing pad bytes are stripped or comparisons ignore them, if a column has an index that requires unique values, inserting into the column values that differ only in number of trailing pad bytes will result in a duplicate-key error. For example, if a table contains `'a'', an attempt to store `'a\0'' causes a duplicate-key error. You should consider the preceding padding and stripping characteristics carefully if you plan to use the *Note `BINARY': binary-varbinary. data type for storing binary data and you require that the value retrieved be exactly the same as the value stored. The following example illustrates how `0x00'-padding of *Note `BINARY': binary-varbinary. values affects column value comparisons: mysql> CREATE TABLE t (c BINARY(3)); Query OK, 0 rows affected (0.01 sec) mysql> INSERT INTO t SET c = 'a'; Query OK, 1 row affected (0.01 sec) mysql> SELECT HEX(c), c = 'a', c = 'a\0\0' from t; +--------+---------+-------------+ | HEX(c) | c = 'a' | c = 'a\0\0' | +--------+---------+-------------+ | 610000 | 0 | 1 | +--------+---------+-------------+ 1 row in set (0.09 sec) If the value retrieved must be the same as the value specified for storage with no padding, it might be preferable to use *Note `VARBINARY': binary-varbinary. or one of the *Note `BLOB': blob. data types instead.  File: manual.info, Node: blob, Next: enum, Prev: binary-varbinary, Up: string-types 11.4.3 The `BLOB' and `TEXT' Types ---------------------------------- A *Note `BLOB': blob. is a binary large object that can hold a variable amount of data. The four *Note `BLOB': blob. types are *Note `TINYBLOB': blob, *Note `BLOB': blob, *Note `MEDIUMBLOB': blob, and *Note `LONGBLOB': blob. These differ only in the maximum length of the values they can hold. The four *Note `TEXT': blob. types are *Note `TINYTEXT': blob, *Note `TEXT': blob, *Note `MEDIUMTEXT': blob, and *Note `LONGTEXT': blob. These correspond to the four *Note `BLOB': blob. types and have the same maximum lengths and storage requirements. See *Note storage-requirements::. *Note `BLOB': blob. values are treated as binary strings (byte strings). They have no character set, and sorting and comparison are based on the numeric values of the bytes in column values. *Note `TEXT': blob. values are treated as nonbinary strings (character strings). They have a character set, and values are sorted and compared based on the collation of the character set. If strict SQL mode is not enabled and you assign a value to a *Note `BLOB': blob. or *Note `TEXT': blob. column that exceeds the column's maximum length, the value is truncated to fit and a warning is generated. For truncation of nonspace characters, you can cause an error to occur (rather than a warning) and suppress insertion of the value by using strict SQL mode. See *Note server-sql-mode::. Beginning with MySQL 5.1.24, truncation of excess trailing spaces from values to be inserted into *Note `TEXT': blob. columns always generates a warning, regardless of the SQL mode. If a *Note `TEXT': blob. column is indexed, index entry comparisons are space-padded at the end. This means that, if the index requires unique values, duplicate-key errors will occur for values that differ only in the number of trailing spaces. For example, if a table contains `'a'', an attempt to store `'a '' causes a duplicate-key error. This is not true for *Note `BLOB': blob. columns. In most respects, you can regard a *Note `BLOB': blob. column as a *Note `VARBINARY': binary-varbinary. column that can be as large as you like. Similarly, you can regard a *Note `TEXT': blob. column as a *Note `VARCHAR': char. column. *Note `BLOB': blob. and *Note `TEXT': blob. differ from *Note `VARBINARY': binary-varbinary. and *Note `VARCHAR': char. in the following ways: * For indexes on *Note `BLOB': blob. and *Note `TEXT': blob. columns, you must specify an index prefix length. For *Note `CHAR': char. and *Note `VARCHAR': char, a prefix length is optional. See *Note column-indexes::. * *Note `BLOB': blob. and *Note `TEXT': blob. columns cannot have `DEFAULT' values. If you use the `BINARY' attribute with a *Note `TEXT': blob. data type, the column is assigned the binary collation of the column character set. `LONG' and `LONG VARCHAR' map to the *Note `MEDIUMTEXT': blob. data type. This is a compatibility feature. MySQL Connector/ODBC defines *Note `BLOB': blob. values as `LONGVARBINARY' and *Note `TEXT': blob. values as `LONGVARCHAR'. Because *Note `BLOB': blob. and *Note `TEXT': blob. values can be extremely long, you might encounter some constraints in using them: * Only the first `max_sort_length' bytes of the column are used when sorting. The default value of `max_sort_length' is 1024. You can make more bytes significant in sorting or grouping by increasing the value of `max_sort_length' at server startup or runtime. Any client can change the value of its session `max_sort_length' variable: mysql> SET max_sort_length = 2000; mysql> SELECT id, comment FROM t -> ORDER BY comment; Another way to use `GROUP BY' or `ORDER BY' on a *Note `BLOB': blob. or *Note `TEXT': blob. column containing long values when you want more than `max_sort_length' bytes to be significant is to convert the column value into a fixed-length object. The standard way to do this is with the `SUBSTRING()' function. For example, the following statement causes 2000 bytes of the `comment' column to be taken into account for sorting: mysql> SELECT id, SUBSTRING(comment,1,2000) FROM t -> ORDER BY SUBSTRING(comment,1,2000); * Instances of *Note `BLOB': blob. or *Note `TEXT': blob. columns in the result of a query that is processed using a temporary table causes the server to use a table on disk rather than in memory because the `MEMORY' storage engine does not support those data types (see *Note internal-temporary-tables::). Use of disk incurs a performance penalty, so include *Note `BLOB': blob. or *Note `TEXT': blob. columns in the query result only if they are really needed. For example, avoid using *Note `SELECT *': select, which selects all columns. * The maximum size of a *Note `BLOB': blob. or *Note `TEXT': blob. object is determined by its type, but the largest value you actually can transmit between the client and server is determined by the amount of available memory and the size of the communications buffers. You can change the message buffer size by changing the value of the `max_allowed_packet' variable, but you must do so for both the server and your client program. For example, both *Note `mysql': mysql. and *Note `mysqldump': mysqldump. enable you to change the client-side `max_allowed_packet' value. See *Note server-parameters::, *Note mysql::, and *Note mysqldump::. You may also want to compare the packet sizes and the size of the data objects you are storing with the storage requirements, see *Note storage-requirements:: Each *Note `BLOB': blob. or *Note `TEXT': blob. value is represented internally by a separately allocated object. This is in contrast to all other data types, for which storage is allocated once per column when the table is opened. In some cases, it may be desirable to store binary data such as media files in *Note `BLOB': blob. or *Note `TEXT': blob. columns. You may find MySQL's string handling functions useful for working with such data. See *Note string-functions::. For security and other reasons, it is usually preferable to do so using application code rather than giving application users the `FILE' privilege. You can discuss specifics for various languages and platforms in the MySQL Forums (`http://forums.mysql.com/').  File: manual.info, Node: enum, Next: set, Prev: blob, Up: string-types 11.4.4 The `ENUM' Type ---------------------- An *Note `ENUM': enum. is a string object with a value chosen from a list of permitted values that are enumerated explicitly in the column specification at table creation time. An enumeration value must be a quoted string literal; it may not be an expression, even one that evaluates to a string value. For example, you can create a table with an *Note `ENUM': enum. column like this: CREATE TABLE sizes ( name ENUM('small', 'medium', 'large') ); However, this version of the previous *Note `CREATE TABLE': create-table. statement does _not_ work: CREATE TABLE sizes ( c1 ENUM('small', CONCAT('med','ium'), 'large') ); You also may not employ a user variable as an enumeration value. This pair of statements do _not_ work: SET @mysize = 'medium'; CREATE TABLE sizes ( name ENUM('small', @mysize, 'large') ); If you wish to use a number as an enumeration value, you must enclose it in quotation marks. If the quotation marks are omitted, the number is regarded as an index. For this and other reasons--as explained later in this section--we strongly recommend that you do _not_ use numbers as enumeration values. Duplicate values in the definition cause a warning, or an error if strict SQL mode is enabled. The value may also be the empty string (`''') or `NULL' under certain circumstances: * If you insert an invalid value into an *Note `ENUM': enum. (that is, a string not present in the list of permitted values), the empty string is inserted instead as a special error value. This string can be distinguished from a `normal' empty string by the fact that this string has the numeric value 0. More about this later. If strict SQL mode is enabled, attempts to insert invalid *Note `ENUM': enum. values result in an error. * If an *Note `ENUM': enum. column is declared to permit `NULL', the `NULL' value is a legal value for the column, and the default value is `NULL'. If an *Note `ENUM': enum. column is declared `NOT NULL', its default value is the first element of the list of permitted values. Each enumeration value has an index: * Values from the list of permissible elements in the column specification are numbered beginning with 1. * The index value of the empty string error value is 0. This means that you can use the following *Note `SELECT': select. statement to find rows into which invalid *Note `ENUM': enum. values were assigned: mysql> SELECT * FROM TBL_NAME WHERE ENUM_COL=0; * The index of the `NULL' value is `NULL'. * The term `index' here refers only to position within the list of enumeration values. It has nothing to do with table indexes. For example, a column specified as `ENUM('one', 'two', 'three')' can have any of the values shown here. The index of each value is also shown. Value Index `NULL' `NULL' `''' 0 `'one'' 1 `'two'' 2 `'three'' 3 An enumeration can have a maximum of 65,535 elements. Trailing spaces are automatically deleted from *Note `ENUM': enum. member values in the table definition when a table is created. When retrieved, values stored into an *Note `ENUM': enum. column are displayed using the lettercase that was used in the column definition. Note that *Note `ENUM': enum. columns can be assigned a character set and collation. For binary or case-sensitive collations, lettercase is taken into account when assigning values to the column. If you retrieve an *Note `ENUM': enum. value in a numeric context, the column value's index is returned. For example, you can retrieve numeric values from an *Note `ENUM': enum. column like this: mysql> SELECT ENUM_COL+0 FROM TBL_NAME; If you store a number into an *Note `ENUM': enum. column, the number is treated as the index into the possible values, and the value stored is the enumeration member with that index. (However, this does _not_ work with *Note `LOAD DATA': load-data, which treats all input as strings.) If the numeric value is quoted, it is still interpreted as an index if there is no matching string in the list of enumeration values. For these reasons, it is not advisable to define an *Note `ENUM': enum. column with enumeration values that look like numbers, because this can easily become confusing. For example, the following column has enumeration members with string values of `'0'', `'1'', and `'2'', but numeric index values of `1', `2', and `3': numbers ENUM('0','1','2') If you store `2', it is interpreted as an index value, and becomes `'1'' (the value with index 2). If you store `'2'', it matches an enumeration value, so it is stored as `'2''. If you store `'3'', it does not match any enumeration value, so it is treated as an index and becomes `'2'' (the value with index 3). mysql> INSERT INTO t (numbers) VALUES(2),('2'),('3'); mysql> SELECT * FROM t; +---------+ | numbers | +---------+ | 1 | | 2 | | 2 | +---------+ *Note `ENUM': enum. values are sorted according to the order in which the enumeration members were listed in the column specification. (In other words, *Note `ENUM': enum. values are sorted according to their index numbers.) For example, `'a'' sorts before `'b'' for `ENUM('a', 'b')', but `'b'' sorts before `'a'' for `ENUM('b', 'a')'. The empty string sorts before nonempty strings, and `NULL' values sort before all other enumeration values. To prevent unexpected results, specify the *Note `ENUM': enum. list in alphabetic order. You can also use `ORDER BY CAST(COL AS CHAR)' or `ORDER BY CONCAT(COL)' to make sure that the column is sorted lexically rather than by index number. Functions such as `SUM()' or `AVG()' that expect a numeric argument cast the argument to a number if necessary. For *Note `ENUM': enum. values, the cast operation causes the index number to be used. To determine all possible values for an *Note `ENUM': enum. column, use *Note `SHOW COLUMNS FROM TBL_NAME LIKE 'ENUM_COL'': show-columns. and parse the *Note `ENUM': enum. definition in the `Type' column of the output. In the C API, *Note `ENUM': enum. values are returned as strings. For information about using result set metadata to distinguish them from other strings, see *Note c-api-data-structures::.  File: manual.info, Node: set, Prev: enum, Up: string-types 11.4.5 The `SET' Type --------------------- A *Note `SET': set. is a string object that can have zero or more values, each of which must be chosen from a list of permitted values specified when the table is created. *Note `SET': set. column values that consist of multiple set members are specified with members separated by commas (``,''). A consequence of this is that *Note `SET': set. member values should not themselves contain commas. For example, a column specified as `SET('one', 'two') NOT NULL' can have any of these values: '' 'one' 'two' 'one,two' A *Note `SET': set. can have a maximum of 64 different members. Duplicate values in the definition cause a warning, or an error if strict SQL mode is enabled. Trailing spaces are automatically deleted from *Note `SET': set. member values in the table definition when a table is created. When retrieved, values stored in a *Note `SET': set. column are displayed using the lettercase that was used in the column definition. Note that *Note `SET': set. columns can be assigned a character set and collation. For binary or case-sensitive collations, lettercase is taken into account when assigning values to the column. MySQL stores *Note `SET': set. values numerically, with the low-order bit of the stored value corresponding to the first set member. If you retrieve a *Note `SET': set. value in a numeric context, the value retrieved has bits set corresponding to the set members that make up the column value. For example, you can retrieve numeric values from a *Note `SET': set. column like this: mysql> SELECT SET_COL+0 FROM TBL_NAME; If a number is stored into a *Note `SET': set. column, the bits that are set in the binary representation of the number determine the set members in the column value. For a column specified as `SET('a','b','c','d')', the members have the following decimal and binary values. *Note Decimal Value Binary Value `SET': set. Member `'a'' `1' `0001' `'b'' `2' `0010' `'c'' `4' `0100' `'d'' `8' `1000' If you assign a value of `9' to this column, that is `1001' in binary, so the first and fourth *Note `SET': set. value members `'a'' and `'d'' are selected and the resulting value is `'a,d''. For a value containing more than one *Note `SET': set. element, it does not matter what order the elements are listed in when you insert the value. It also does not matter how many times a given element is listed in the value. When the value is retrieved later, each element in the value appears once, with elements listed according to the order in which they were specified at table creation time. For example, suppose that a column is specified as `SET('a','b','c','d')': mysql> CREATE TABLE myset (col SET('a', 'b', 'c', 'd')); If you insert the values `'a,d'', `'d,a'', `'a,d,d'', `'a,d,a'', and `'d,a,d'': mysql> INSERT INTO myset (col) VALUES -> ('a,d'), ('d,a'), ('a,d,a'), ('a,d,d'), ('d,a,d'); Query OK, 5 rows affected (0.01 sec) Records: 5 Duplicates: 0 Warnings: 0 Then all these values appear as `'a,d'' when retrieved: mysql> SELECT col FROM myset; +------+ | col | +------+ | a,d | | a,d | | a,d | | a,d | | a,d | +------+ 5 rows in set (0.04 sec) If you set a *Note `SET': set. column to an unsupported value, the value is ignored and a warning is issued: mysql> INSERT INTO myset (col) VALUES ('a,d,d,s'); Query OK, 1 row affected, 1 warning (0.03 sec) mysql> SHOW WARNINGS; +---------+------+------------------------------------------+ | Level | Code | Message | +---------+------+------------------------------------------+ | Warning | 1265 | Data truncated for column 'col' at row 1 | +---------+------+------------------------------------------+ 1 row in set (0.04 sec) mysql> SELECT col FROM myset; +------+ | col | +------+ | a,d | | a,d | | a,d | | a,d | | a,d | | a,d | +------+ 6 rows in set (0.01 sec) If strict SQL mode is enabled, attempts to insert invalid *Note `SET': set. values result in an error. *Note `SET': set. values are sorted numerically. `NULL' values sort before non-`NULL' *Note `SET': set. values. Functions such as `SUM()' or `AVG()' that expect a numeric argument cast the argument to a number if necessary. For *Note `SET': set. values, the cast operation causes the numeric value to be used. Normally, you search for *Note `SET': set. values using the `FIND_IN_SET()' function or the `LIKE' operator: mysql> SELECT * FROM TBL_NAME WHERE FIND_IN_SET('VALUE',SET_COL)>0; mysql> SELECT * FROM TBL_NAME WHERE SET_COL LIKE '%VALUE%'; The first statement finds rows where SET_COL contains the VALUE set member. The second is similar, but not the same: It finds rows where SET_COL contains VALUE anywhere, even as a substring of another set member. The following statements also are legal: mysql> SELECT * FROM TBL_NAME WHERE SET_COL & 1; mysql> SELECT * FROM TBL_NAME WHERE SET_COL = 'VAL1,VAL2'; The first of these statements looks for values containing the first set member. The second looks for an exact match. Be careful with comparisons of the second type. Comparing set values to `'VAL1,VAL2'' returns different results than comparing values to `'VAL2,VAL1''. You should specify the values in the same order they are listed in the column definition. To determine all possible values for a *Note `SET': set. column, use `SHOW COLUMNS FROM TBL_NAME LIKE SET_COL' and parse the *Note `SET': set. definition in the `Type' column of the output. In the C API, *Note `SET': set. values are returned as strings. For information about using result set metadata to distinguish them from other strings, see *Note c-api-data-structures::.  File: manual.info, Node: storage-requirements, Next: out-of-range-and-overflow, Prev: string-types, Up: data-types 11.5 Data Type Storage Requirements =================================== The storage requirements for data vary, according to the storage engine being used for the table in question. Different storage engines use different methods for recording the raw data and different data types. In addition, some engines may compress the information in a given row, either on a column or entire row basis, making calculation of the storage requirements for a given table or column structure. However, all storage engines must communicate and exchange information on a given row within a table using the same structure, and this information is consistent, irrespective of the storage engine used to write the information to disk. This sections includes some guideliness and information for the storage requirements for each data type supported by MySQL, including details for the internal format and the sizes used by storage engines that used a fixed size representation for different types. Information is listed by category or storage engine. The internal representation of a table has a maximum row size of 65,535 bytes, even if the storage engine is capable of supporting larger rows. This figure excludes *Note `BLOB': blob. or *Note `TEXT': blob. columns, which contribute only 9 to 12 bytes toward this size. For *Note `BLOB': blob. and `TEXT' data, the information is stored internally in a different area of memory than the row buffer. Different storage engines handle the allocation and storage of this data in different ways, according to the method they use for handling the corresponding types. For more information, see *Note storage-engines::, and *Note column-count-limit::. *Important*: For tables using the *Note `NDBCLUSTER': mysql-cluster. storage engine, there is the factor of _4-byte alignment_ to be taken into account when calculating storage requirements. This means that all *Note `NDB': mysql-cluster. data storage is done in multiples of 4 bytes. Thus, a column value that would take 15 bytes in a table using a storage engine other than *Note `NDB': mysql-cluster. requires 16 bytes in an *Note `NDB': mysql-cluster. table. This requirement applies in addition to any other considerations that are discussed in this section. For example, in *Note `NDBCLUSTER': mysql-cluster. tables, the *Note `TINYINT': numeric-types, *Note `SMALLINT': numeric-types, *Note `MEDIUMINT': numeric-types, and *Note `INTEGER': numeric-types. (*Note `INT': numeric-types.) column types each require 4 bytes storage per record due to the alignment factor. An exception to this rule is the *Note `BIT': numeric-types. type, which is _not_ 4-byte aligned. In MySQL Cluster tables, a `BIT(M)' column takes M bits of storage space. However, if a table definition contains 1 or more *Note `BIT': numeric-types. columns (up to 32 *Note `BIT': numeric-types. columns), then *Note `NDBCLUSTER': mysql-cluster. reserves 4 bytes (32 bits) per row for these. If a table definition contains more than 32 *Note `BIT': numeric-types. columns (up to 64 such columns), then *Note `NDBCLUSTER': mysql-cluster. reserves 8 bytes (that is, 64 bits) per row. In addition, while a `NULL' itself does not require any storage space, *Note `NDBCLUSTER': mysql-cluster. reserves 4 bytes per row if the table definition contains any columns defined as `NULL', up to 32 `NULL' columns. (If a MySQL Cluster table is defined with more than 32 `NULL' columns up to 64 `NULL' columns, then 8 bytes per row is reserved.) When calculating storage requirements for MySQL Cluster tables, you must also remember that every table using the *Note `NDBCLUSTER': mysql-cluster. storage engine requires a primary key; if no primary key is defined by the user, then a `hidden' primary key will be created by *Note `NDB': mysql-cluster. This hidden primary key consumes 31-35 bytes per table record. You may find the `ndb_size.pl' utility to be useful for estimating *Note `NDB': mysql-cluster. storage requirements. This Perl script connects to a current MySQL (non-Cluster) database and creates a report on how much space that database would require if it used the *Note `NDBCLUSTER': mysql-cluster. storage engine. See *Note mysql-cluster-programs-ndb-size-pl::, for more information. * Storage Requirements for Numeric Types * Data Type Storage Required *Note `TINYINT': 1 byte numeric-types. *Note `SMALLINT': 2 bytes numeric-types. *Note `MEDIUMINT': 3 bytes numeric-types. *Note `INT': numeric-types, 4 bytes *Note `INTEGER': numeric-types. *Note `BIGINT': 8 bytes numeric-types. `FLOAT(P)' 4 bytes if 0 <= P <= 24, 8 bytes if 25 <= P <= 53 *Note `FLOAT': numeric-types. 4 bytes `DOUBLE [PRECISION]', *Note 8 bytes `REAL': numeric-types. `DECIMAL(M,D)', Varies; see following discussion `NUMERIC(M,D)' `BIT(M)' approximately (M+7)/8 bytes Values for *Note `DECIMAL': numeric-types. (and *Note `NUMERIC': numeric-types.) columns are represented using a binary format that packs nine decimal (base 10) digits into four bytes. Storage for the integer and fractional parts of each value are determined separately. Each multiple of nine digits requires four bytes, and the `leftover' digits require some fraction of four bytes. The storage required for excess digits is given by the following table. Leftover Digits Number of Bytes 0 0 1 1 2 1 3 2 4 2 5 3 6 3 7 4 8 4 * Storage Requirements for Date and Time Types * Data Type Storage Required *Note `DATE': datetime. 3 bytes *Note `TIME': time. 3 bytes *Note `DATETIME': datetime. 8 bytes *Note `TIMESTAMP': datetime. 4 bytes *Note `YEAR': year. 1 byte The storage requirements shown in the table arise from the way that MySQL represents temporal values: * *Note `DATE': datetime.: A three-byte integer packed as `DD' + `MM'x32 + `YYYY'x16x32 * *Note `TIME': time.: A three-byte integer packed as `DD'x24x3600 + `HH'x3600 + `MM'x60 + `SS' * *Note `DATETIME': datetime.: Eight bytes: * A four-byte integer packed as `YYYY'x10000 + `MM'x100 + `DD' * A four-byte integer packed as `HH'x10000 + `MM'x100 + `SS' * *Note `TIMESTAMP': datetime.: A four-byte integer representing seconds UTC since the epoch (`'1970-01-01 00:00:00'' UTC) * *Note `YEAR': year.: A one-byte integer * Storage Requirements for String Types * In the following table, M represents the declared column length in characters for nonbinary string types and bytes for binary string types. L represents the actual length in bytes of a given string value. Data Type Storage Required `CHAR(M)' M x W bytes, 0 `<= M <=' 255, where W is the number of bytes required for the maximum-length character in the character set `BINARY(M)' M bytes, 0 `<= M <=' 255 `VARCHAR(M)', `VARBINARY(M)' L + 1 bytes if column values require 0 - 255 bytes, L + 2 bytes if values may require more than 255 bytes *Note `TINYBLOB': blob, L + 1 bytes, where L < 2^8 *Note `TINYTEXT': blob. *Note `BLOB': blob, *Note L + 2 bytes, where L < 2^16 `TEXT': blob. *Note `MEDIUMBLOB': blob, L + 3 bytes, where L < 2^24 *Note `MEDIUMTEXT': blob. *Note `LONGBLOB': blob, L + 4 bytes, where L < 2^32 *Note `LONGTEXT': blob. `ENUM('VALUE1','VALUE2',...)' 1 or 2 bytes, depending on the number of enumeration values (65,535 values maximum) `SET('VALUE1','VALUE2',...)' 1, 2, 3, 4, or 8 bytes, depending on the number of set members (64 members maximum) Variable-length string types are stored using a length prefix plus data. The length prefix requires from one to four bytes depending on the data type, and the value of the prefix is L (the byte length of the string). For example, storage for a *Note `MEDIUMTEXT': blob. value requires L bytes to store the value plus three bytes to store the length of the value. To calculate the number of bytes used to store a particular *Note `CHAR': char, *Note `VARCHAR': char, or *Note `TEXT': blob. column value, you must take into account the character set used for that column and whether the value contains multi-byte characters. In particular, when using the `utf8' Unicode character set, you must keep in mind that not all characters use the same number of bytes and can require up to three bytes per character. For a breakdown of the storage used for different categories of `utf8' characters, see *Note charset-unicode::. *Note `VARCHAR': char, *Note `VARBINARY': binary-varbinary, and the *Note `BLOB': blob. and *Note `TEXT': blob. types are variable-length types. For each, the storage requirements depend on these factors: * The actual length of the column value * The column's maximum possible length * The character set used for the column, because some character sets contain multi-byte characters For example, a `VARCHAR(255)' column can hold a string with a maximum length of 255 characters. Assuming that the column uses the `latin1' character set (one byte per character), the actual storage required is the length of the string (L), plus one byte to record the length of the string. For the string `'abcd'', L is 4 and the storage requirement is five bytes. If the same column is instead declared to use the `ucs2' double-byte character set, the storage requirement is 10 bytes: The length of `'abcd'' is eight bytes and the column requires two bytes to store lengths because the maximum length is greater than 255 (up to 510 bytes). The effective maximum number of _bytes_ that can be stored in a *Note `VARCHAR': char. or *Note `VARBINARY': binary-varbinary. column is subject to the maximum row size of 65,535 bytes, which is shared among all columns. For a *Note `VARCHAR': char. column that stores multi-byte characters, the effective maximum number of _characters_ is less. For example, `utf8' characters can require up to three bytes per character, so a *Note `VARCHAR': char. column that uses the `utf8' character set can be declared to be a maximum of 21,844 characters. See *Note column-count-limit::. The *Note `NDBCLUSTER': mysql-cluster. storage engine in MySQL 5.1 supports variable-width columns. This means that a *Note `VARCHAR': char. column in a MySQL Cluster table requires the same amount of storage as it would using any other storage engine, with the exception that such values are 4-byte aligned. Thus, the string `'abcd'' stored in a `VARCHAR(50)' column using the `latin1' character set requires 8 bytes (rather than 6 bytes for the same column value in a `MyISAM' table). This represents a change in behavior from earlier versions of *Note `NDBCLUSTER': mysql-cluster, where a `VARCHAR(50)' column would require 52 bytes storage per record regardless of the length of the string being stored. *Note `TEXT': blob. and *Note `BLOB': blob. columns are implemented differently in the NDB Cluster storage engine, wherein each row in a *Note `TEXT': blob. column is made up of two separate parts. One of these is of fixed size (256 bytes), and is actually stored in the original table. The other consists of any data in excess of 256 bytes, which is stored in a hidden table. The rows in this second table are always 2,000 bytes long. This means that the size of a *Note `TEXT': blob. column is 256 if SIZE <= 256 (where SIZE represents the size of the row); otherwise, the size is 256 + SIZE + (2000 - (SIZE - 256) % 2000). The size of an *Note `ENUM': enum. object is determined by the number of different enumeration values. One byte is used for enumerations with up to 255 possible values. Two bytes are used for enumerations having between 256 and 65,535 possible values. See *Note enum::. The size of a *Note `SET': set. object is determined by the number of different set members. If the set size is N, the object occupies `(N+7)/8' bytes, rounded up to 1, 2, 3, 4, or 8 bytes. A *Note `SET': set. can have a maximum of 64 members. See *Note set::.  File: manual.info, Node: out-of-range-and-overflow, Next: choosing-types, Prev: storage-requirements, Up: data-types 11.6 Out-of-Range and Overflow Handling ======================================= When MySQL stores a value in a numeric column that is outside the permissible range of the column data type, the result depends on the SQL mode in effect at the time: * If strict SQL mode is enabled, MySQL rejects the out-of-range value with an error, and the insert fails, in accordance with the SQL standard. * If no restrictive modes are enabled, MySQL clips the value to the appropriate endpoint of the range and stores the resulting value instead. When an out-of-range value is assigned to an integer column, MySQL stores the value representing the corresponding endpoint of the column data type range. If you store 256 into a *Note `TINYINT': numeric-types. or `TINYINT UNSIGNED' column, MySQL stores 127 or 255, respectively. When a floating-point or fixed-point column is assigned a value that exceeds the range implied by the specified (or default) precision and scale, MySQL stores the value representing the corresponding endpoint of that range. Column-assignment conversions that occur due to clipping when MySQL is not operating in strict mode are reported as warnings for *Note `ALTER TABLE': alter-table, *Note `LOAD DATA INFILE': load-data, *Note `UPDATE': update, and multiple-row *Note `INSERT': insert. statements. In strict mode, these statements fail, and some or all the values will not be inserted or changed, depending on whether the table is a transactional table and other factors. For details, see *Note server-sql-mode::. In MySQL 5.1, overflow handling during numeric expression evaluation depends on the types of the operands: * Integer overflow results in silent wraparound. * `DECIMAL' overflow results in a truncated result and a warning. * Floating-point overflow produces a `NULL' result. Before MySQL 5.1.24, overflow for some operations results in `+INF', `-INF', or `NaN'. For example, the largest signed *Note `BIGINT': numeric-types. value is 9223372036854775807, so the following expression wraps around to the minimum *Note `BIGINT': numeric-types. value: mysql> SELECT 9223372036854775807 + 1; +-------------------------+ | 9223372036854775807 + 1 | +-------------------------+ | -9223372036854775808 | +-------------------------+ To enable the operation to succeed in this case, convert the value to unsigned; mysql> SELECT CAST(9223372036854775807 AS UNSIGNED) + 1; +-------------------------------------------+ | CAST(9223372036854775807 AS UNSIGNED) + 1 | +-------------------------------------------+ | 9223372036854775808 | +-------------------------------------------+ Whether overflow occurs depends on the range of the operands, so another way to handle the preceding expression is to use exact-value arithmetic because *Note `DECIMAL': numeric-types. values have a larger range than integers: mysql> SELECT 9223372036854775807.0 + 1; +---------------------------+ | 9223372036854775807.0 + 1 | +---------------------------+ | 9223372036854775808.0 | +---------------------------+ Subtraction between integer values, where one is of type `UNSIGNED', produces an unsigned result by default. If the result would otherwise have been negative, it becomes the maximum integer value. If the `NO_UNSIGNED_SUBTRACTION' SQL mode is enabled, the result is negative. mysql> SET sql_mode = ''; mysql> SELECT CAST(0 AS UNSIGNED) - 1; +-------------------------+ | CAST(0 AS UNSIGNED) - 1 | +-------------------------+ | 18446744073709551615 | +-------------------------+ mysql> SET sql_mode = 'NO_UNSIGNED_SUBTRACTION'; mysql> SELECT CAST(0 AS UNSIGNED) - 1; +-------------------------+ | CAST(0 AS UNSIGNED) - 1 | +-------------------------+ | -1 | +-------------------------+ If the result of such an operation is used to update an `UNSIGNED' integer column, the result is clipped to the maximum value for the column type, or clipped to 0 if `NO_UNSIGNED_SUBTRACTION' is enabled. If strict SQL mode is enabled, an error occurs and the column remains unchanged.  File: manual.info, Node: choosing-types, Next: other-vendor-data-types, Prev: out-of-range-and-overflow, Up: data-types 11.7 Choosing the Right Type for a Column ========================================= For optimum storage, you should try to use the most precise type in all cases. For example, if an integer column is used for values in the range from `1' to `99999', `MEDIUMINT UNSIGNED' is the best type. Of the types that represent all the required values, this type uses the least amount of storage. All basic calculations (`+', `-', `*', and `/') with *Note `DECIMAL': numeric-types. columns are done with precision of 65 decimal (base 10) digits. See *Note numeric-type-overview::. If accuracy is not too important or if speed is the highest priority, the *Note `DOUBLE': numeric-types. type may be good enough. For high precision, you can always convert to a fixed-point type stored in a *Note `BIGINT': numeric-types. This enables you to do all calculations with 64-bit integers and then convert results back to floating-point values as necessary. `PROCEDURE ANALYSE' can be used to obtain suggestions for optimal column data types. For more information, see *Note procedure-analyse::.  File: manual.info, Node: other-vendor-data-types, Prev: choosing-types, Up: data-types 11.8 Using Data Types from Other Database Engines ================================================= To facilitate the use of code written for SQL implementations from other vendors, MySQL maps data types as shown in the following table. These mappings make it easier to import table definitions from other database systems into MySQL. Other Vendor Type MySQL Type *Note `BOOL': *Note `TINYINT': numeric-types. numeric-types. *Note `BOOLEAN': *Note `TINYINT': numeric-types. numeric-types. `CHARACTER VARYING(M)' `VARCHAR(M)' *Note `FIXED': *Note `DECIMAL': numeric-types. numeric-types. *Note `FLOAT4': *Note `FLOAT': numeric-types. numeric-types. *Note `FLOAT8': *Note `DOUBLE': numeric-types. numeric-types. *Note `INT1': *Note `TINYINT': numeric-types. numeric-types. *Note `INT2': *Note `SMALLINT': numeric-types. numeric-types. *Note `INT3': *Note `MEDIUMINT': numeric-types. numeric-types. *Note `INT4': *Note `INT': numeric-types. numeric-types. `INT8' *Note `BIGINT': numeric-types. `LONG VARBINARY' *Note `MEDIUMBLOB': blob. `LONG VARCHAR' *Note `MEDIUMTEXT': blob. `LONG' *Note `MEDIUMTEXT': blob. *Note `MIDDLEINT': *Note `MEDIUMINT': numeric-types. numeric-types. *Note `NUMERIC': *Note `DECIMAL': numeric-types. numeric-types. Data type mapping occurs at table creation time, after which the original type specifications are discarded. If you create a table with types used by other vendors and then issue a `DESCRIBE TBL_NAME' statement, MySQL reports the table structure using the equivalent MySQL types. For example: mysql> CREATE TABLE t (a BOOL, b FLOAT8, c LONG VARCHAR, d NUMERIC); Query OK, 0 rows affected (0.00 sec) mysql> DESCRIBE t; +-------+---------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +-------+---------------+------+-----+---------+-------+ | a | tinyint(1) | YES | | NULL | | | b | double | YES | | NULL | | | c | mediumtext | YES | | NULL | | | d | decimal(10,0) | YES | | NULL | | +-------+---------------+------+-----+---------+-------+ 4 rows in set (0.01 sec)  File: manual.info, Node: functions, Next: sql-syntax, Prev: data-types, Up: Top 12 Functions and Operators ************************** * Menu: * func-op-summary-ref:: Function and Operator Reference * type-conversion:: Type Conversion in Expression Evaluation * non-typed-operators:: Operators * control-flow-functions:: Control Flow Functions * string-functions:: String Functions * numeric-functions:: Numeric Functions and Operators * date-and-time-functions:: Date and Time Functions * mysql-calendar:: What Calendar Is Used By MySQL? * fulltext-search:: Full-Text Search Functions * cast-functions:: Cast Functions and Operators * xml-functions:: XML Functions * bit-functions:: Bit Functions * encryption-functions:: Encryption and Compression Functions * information-functions:: Information Functions * miscellaneous-functions:: Miscellaneous Functions * group-by-functions-and-modifiers:: Functions and Modifiers for Use with `GROUP BY' Clauses * spatial-extensions:: Spatial Extensions * precision-math:: Precision Math Expressions can be used at several points in SQL statements, such as in the `ORDER BY' or `HAVING' clauses of *Note `SELECT': select. statements, in the `WHERE' clause of a *Note `SELECT': select, *Note `DELETE': delete, or *Note `UPDATE': update. statement, or in *Note `SET': set-option. statements. Expressions can be written using literal values, column values, `NULL', built-in functions, stored functions, user-defined functions, and operators. This chapter describes the functions and operators that are permitted for writing expressions in MySQL. Instructions for writing stored functions and user-defined functions are given in *Note stored-routines::, and *Note adding-functions::. See *Note function-resolution::, for the rules describing how the server interprets references to different kinds of functions. An expression that contains `NULL' always produces a `NULL' value unless otherwise indicated in the documentation for a particular function or operator. *Note*: By default, there must be no whitespace between a function name and the parenthesis following it. This helps the MySQL parser distinguish between function calls and references to tables or columns that happen to have the same name as a function. However, spaces around function arguments are permitted. You can tell the MySQL server to accept spaces after function names by starting it with the `--sql-mode=IGNORE_SPACE' option. (See *Note server-sql-mode::.) Individual client programs can request this behavior by using the `CLIENT_IGNORE_SPACE' option for *Note `mysql_real_connect()': mysql-real-connect. In either case, all function names become reserved words. For the sake of brevity, most examples in this chapter display the output from the *Note `mysql': mysql. program in abbreviated form. Rather than showing examples in this format: mysql> SELECT MOD(29,9); +-----------+ | mod(29,9) | +-----------+ | 2 | +-----------+ 1 rows in set (0.00 sec) This format is used instead: mysql> SELECT MOD(29,9); -> 2  File: manual.info, Node: func-op-summary-ref, Next: type-conversion, Prev: functions, Up: functions 12.1 Function and Operator Reference ==================================== *Note*: This table is part of an ongoing process to expand and simplify the information provided on these elements. Further improvements to the table, and corresponding descriptions will be applied over the coming months. *Functions/Operators* Name Description `ABS()' Return the absolute value `ACOS()' Return the arc cosine `ADDDATE()' Add time values (intervals) to a date value `ADDTIME()' Add time `AES_DECRYPT()' Decrypt using AES `AES_ENCRYPT()' Encrypt using AES `AND', `&&' Logical AND `ASCII()' Return numeric value of left-most character `ASIN()' Return the arc sine `=' Assign a value (as part of a *Note `SET': set-option. statement, or as part of the `SET' clause in an *Note `UPDATE': update. statement) `:=' Assign a value `ATAN2()', `ATAN()' Return the arc tangent of the two arguments `ATAN()' Return the arc tangent `AVG()' Return the average value of the argument `BENCHMARK()' Repeatedly execute an expression `BETWEEN ... AND ... ' Check whether a value is within a range of values `BIN()' Return a string representation of the argument `BINARY' Cast a string to a binary string `BIT_AND()' Return bitwise and `BIT_COUNT()' Return the number of bits that are set `BIT_LENGTH()' Return length of argument in bits `BIT_OR()' Return bitwise or `BIT_XOR()' Return bitwise xor `&' Bitwise AND `~' Invert bits `|' Bitwise OR `^' Bitwise XOR `CASE' Case operator `CAST()' Cast a value as a certain type `CEIL()' Return the smallest integer value not less than the argument `CEILING()' Return the smallest integer value not less than the argument `CHAR_LENGTH()' Return number of characters in argument `CHAR()' Return the character for each integer passed `CHARACTER_LENGTH()' A synonym for CHAR_LENGTH() `CHARSET()' Return the character set of the argument `COALESCE()' Return the first non-NULL argument `COERCIBILITY()' Return the collation coercibility value of the string argument `COLLATION()' Return the collation of the string argument `COMPRESS()' Return result as a binary string `CONCAT_WS()' Return concatenate with separator `CONCAT()' Return concatenated string `CONNECTION_ID()' Return the connection ID (thread ID) for the connection `CONV()' Convert numbers between different number bases `CONVERT_TZ()' Convert from one timezone to another `Convert()' Cast a value as a certain type `COS()' Return the cosine `COT()' Return the cotangent `COUNT(DISTINCT)' Return the count of a number of different values `COUNT()' Return a count of the number of rows returned `CRC32()' Compute a cyclic redundancy check value `CURDATE()' Return the current date `CURRENT_DATE()', Synonyms for CURDATE() `CURRENT_DATE' `CURRENT_TIME()', Synonyms for CURTIME() `CURRENT_TIME' `CURRENT_TIMESTAMP()', Synonyms for NOW() `CURRENT_TIMESTAMP' `CURRENT_USER()', The authenticated user name and host name `CURRENT_USER' `CURTIME()' Return the current time `DATABASE()' Return the default (current) database name `DATE_ADD()' Add time values (intervals) to a date value `DATE_FORMAT()' Format date as specified `DATE_SUB()' Subtract a time value (interval) from a date `DATE()' Extract the date part of a date or datetime expression `DATEDIFF()' Subtract two dates `DAY()' Synonym for DAYOFMONTH() `DAYNAME()' Return the name of the weekday `DAYOFMONTH()' Return the day of the month (0-31) `DAYOFWEEK()' Return the weekday index of the argument `DAYOFYEAR()' Return the day of the year (1-366) `DECODE()' Decodes a string encrypted using ENCODE() `DEFAULT()' Return the default value for a table column `DEGREES()' Convert radians to degrees `DES_DECRYPT()' Decrypt a string `DES_ENCRYPT()' Encrypt a string `DIV' Integer division `/' Division operator `ELT()' Return string at index number `ENCODE()' Encode a string `ENCRYPT()' Encrypt a string `<=>' NULL-safe equal to operator `=' Equal operator `EXP()' Raise to the power of `EXPORT_SET()' Return a string such that for every bit set in the value bits, you get an on string and for every unset bit, you get an off string `EXTRACT()' Extract part of a date `ExtractValue()' Extracts a value from an XML string using XPath notation `FIELD()' Return the index (position) of the first argument in the subsequent arguments `FIND_IN_SET()' Return the index position of the first argument within the second argument `FLOOR()' Return the largest integer value not greater than the argument `FORMAT()' Return a number formatted to specified number of decimal places `FOUND_ROWS()' For a SELECT with a LIMIT clause, the number of rows that would be returned were there no LIMIT clause `FROM_DAYS()' Convert a day number to a date `FROM_UNIXTIME()' Format UNIX timestamp as a date `GET_FORMAT()' Return a date format string `GET_LOCK()' Get a named lock `>=' Greater than or equal operator `>' Greater than operator `GREATEST()' Return the largest argument `GROUP_CONCAT()' Return a concatenated string `HEX()' Return a hexadecimal representation of a decimal or string value `HOUR()' Extract the hour `IF()' If/else construct `IFNULL()' Null if/else construct `IN()' Check whether a value is within a set of values `INET_ATON()' Return the numeric value of an IP address `INET_NTOA()' Return the IP address from a numeric value `INSERT()' Insert a substring at the specified position up to the specified number of characters `INSTR()' Return the index of the first occurrence of substring `INTERVAL()' Return the index of the argument that is less than the first argument `IS_FREE_LOCK()' Checks whether the named lock is free `IS NOT NULL' NOT NULL value test `IS NOT' Test a value against a boolean `IS NULL' NULL value test `IS_USED_LOCK()' Checks whether the named lock is in use. Return connection identifier if true. `IS' Test a value against a boolean `ISNULL()' Test whether the argument is NULL `LAST_DAY' Return the last day of the month for the argument `LAST_INSERT_ID()' Value of the AUTOINCREMENT column for the last INSERT `LCASE()' Synonym for LOWER() `LEAST()' Return the smallest argument `<<' Left shift `LEFT()' Return the leftmost number of characters as specified `LENGTH()' Return the length of a string in bytes `<=' Less than or equal operator `<' Less than operator `LIKE' Simple pattern matching `LN()' Return the natural logarithm of the argument `LOAD_FILE()' Load the named file `LOCALTIME()', `LOCALTIME' Synonym for NOW() `LOCALTIMESTAMP', Synonym for NOW() `LOCALTIMESTAMP()' `LOCATE()' Return the position of the first occurrence of substring `LOG10()' Return the base-10 logarithm of the argument `LOG2()' Return the base-2 logarithm of the argument `LOG()' Return the natural logarithm of the first argument `LOWER()' Return the argument in lowercase `LPAD()' Return the string argument, left-padded with the specified string `LTRIM()' Remove leading spaces `MAKE_SET()' Return a set of comma-separated strings that have the corresponding bit in bits set `MAKEDATE()' Create a date from the year and day of year `MAKETIME' MAKETIME() `MASTER_POS_WAIT()' Block until the slave has read and applied all updates up to the specified position `MATCH' Perform full-text search `MAX()' Return the maximum value `MD5()' Calculate MD5 checksum `MICROSECOND()' Return the microseconds from argument `MID()' Return a substring starting from the specified position `MIN()' Return the minimum value `-' Minus operator `MINUTE()' Return the minute from the argument `MOD()' Return the remainder `%' Modulo operator `MONTH()' Return the month from the date passed `MONTHNAME()' Return the name of the month `NAME_CONST()' Causes the column to have the given name `NOT BETWEEN ... AND ...' Check whether a value is not within a range of values `!=', `<>' Not equal operator `NOT IN()' Check whether a value is not within a set of values `NOT LIKE' Negation of simple pattern matching `NOT REGEXP' Negation of REGEXP `NOT', `!' Negates value `NOW()' Return the current date and time `NULLIF()' Return NULL if expr1 = expr2 `OCT()' Return an octal representation of a decimal number `OCTET_LENGTH()' A synonym for LENGTH() `OLD_PASSWORD()' Return the value of the pre-4.1 implementation of PASSWORD `||', `OR' Logical OR `ORD()' Return character code for leftmost character of the argument `PASSWORD()' Calculate and return a password string `PERIOD_ADD()' Add a period to a year-month `PERIOD_DIFF()' Return the number of months between periods `PI()' Return the value of pi `+' Addition operator `POSITION()' A synonym for LOCATE() `POW()' Return the argument raised to the specified power `POWER()' Return the argument raised to the specified power *Note `PROCEDURE ANALYSE()': Analyze the results of a query procedure-analyse. `QUARTER()' Return the quarter from a date argument `QUOTE()' Escape the argument for use in an SQL statement `RADIANS()' Return argument converted to radians `RAND()' Return a random floating-point value `REGEXP' Pattern matching using regular expressions `RELEASE_LOCK()' Releases the named lock `REPEAT()' Repeat a string the specified number of times `REPLACE()' Replace occurrences of a specified string `REVERSE()' Reverse the characters in a string `>>' Right shift `RIGHT()' Return the specified rightmost number of characters `RLIKE' Synonym for REGEXP `ROUND()' Round the argument `ROW_COUNT()' The number of rows updated `RPAD()' Append string the specified number of times `RTRIM()' Remove trailing spaces `SCHEMA()' A synonym for DATABASE() `SEC_TO_TIME()' Converts seconds to 'HH:MM:SS' format `SECOND()' Return the second (0-59) `SESSION_USER()' Synonym for USER() `SHA1()', `SHA()' Calculate an SHA-1 160-bit checksum `SIGN()' Return the sign of the argument `SIN()' Return the sine of the argument `SLEEP()' Sleep for a number of seconds `SOUNDEX()' Return a soundex string `SOUNDS LIKE' Compare sounds `SPACE()' Return a string of the specified number of spaces `SQRT()' Return the square root of the argument `STD()' Return the population standard deviation `STDDEV_POP()' Return the population standard deviation `STDDEV_SAMP()' Return the sample standard deviation `STDDEV()' Return the population standard deviation `STR_TO_DATE()' Convert a string to a date `STRCMP()' Compare two strings `SUBDATE()' A synonym for DATE_SUB() when invoked with three arguments `SUBSTR()' Return the substring as specified `SUBSTRING_INDEX()' Return a substring from a string before the specified number of occurrences of the delimiter `SUBSTRING()' Return the substring as specified `SUBTIME()' Subtract times `SUM()' Return the sum `SYSDATE()' Return the time at which the function executes `SYSTEM_USER()' Synonym for USER() `TAN()' Return the tangent of the argument `TIME_FORMAT()' Format as time `TIME_TO_SEC()' Return the argument converted to seconds `TIME()' Extract the time portion of the expression passed `TIMEDIFF()' Subtract time `*' Multiplication operator `TIMESTAMP()' With a single argument, this function returns the date or datetime expression; with two arguments, the sum of the arguments `TIMESTAMPADD()' Add an interval to a datetime expression `TIMESTAMPDIFF()' Subtract an interval from a datetime expression `TO_DAYS()' Return the date argument converted to days `TRIM()' Remove leading and trailing spaces `TRUNCATE()' Truncate to specified number of decimal places `UCASE()' Synonym for UPPER() `-' Change the sign of the argument `UNCOMPRESS()' Uncompress a string compressed `UNCOMPRESSED_LENGTH()' Return the length of a string before compression `UNHEX()' Convert each pair of hexadecimal digits to a character `UNIX_TIMESTAMP()' Return a UNIX timestamp `UpdateXML()' Return replaced XML fragment `UPPER()' Convert to uppercase `USER()' The user name and host name provided by the client `UTC_DATE()' Return the current UTC date `UTC_TIME()' Return the current UTC time `UTC_TIMESTAMP()' Return the current UTC date and time `UUID_SHORT()' Return an integer-valued universal identifier `UUID()' Return a Universal Unique Identifier (UUID) `VALUES()' Defines the values to be used during an INSERT `VAR_POP()' Return the population standard variance `VAR_SAMP()' Return the sample variance `VARIANCE()' Return the population standard variance `VERSION()' Returns a string that indicates the MySQL server version `WEEK()' Return the week number `WEEKDAY()' Return the weekday index `WEEKOFYEAR()' Return the calendar week of the date (0-53) `XOR' Logical XOR `YEAR()' Return the year `YEARWEEK()' Return the year and week  File: manual.info, Node: type-conversion, Next: non-typed-operators, Prev: func-op-summary-ref, Up: functions 12.2 Type Conversion in Expression Evaluation ============================================= When an operator is used with operands of different types, type conversion occurs to make the operands compatible. Some conversions occur implicitly. For example, MySQL automatically converts numbers to strings as necessary, and vice versa. mysql> SELECT 1+'1'; -> 2 mysql> SELECT CONCAT(2,' test'); -> '2 test' It is also possible to convert a number to a string explicitly using the `CAST()' function. Conversion occurs implicitly with the `CONCAT()' function because it expects string arguments. mysql> SELECT 38.8, CAST(38.8 AS CHAR); -> 38.8, '38.8' mysql> SELECT 38.8, CONCAT(38.8); -> 38.8, '38.8' See later in this section for information about the character set of implicit number-to-string conversions. The following rules describe how conversion occurs for comparison operations: * If one or both arguments are `NULL', the result of the comparison is `NULL', except for the `NULL'-safe `<=>' equality comparison operator. For `NULL <=> NULL', the result is true. No conversion is needed. * If both arguments in a comparison operation are strings, they are compared as strings. * If both arguments are integers, they are compared as integers. * Hexadecimal values are treated as binary strings if not compared to a number. * If one of the arguments is a *Note `TIMESTAMP': datetime. or *Note `DATETIME': datetime. column and the other argument is a constant, the constant is converted to a timestamp before the comparison is performed. This is done to be more ODBC-friendly. Note that this is not done for the arguments to `IN()'! To be safe, always use complete datetime, date, or time strings when doing comparisons. For example, to achieve best results when using `BETWEEN' with date or time values, use `CAST()' to explicitly convert the values to the desired data type. * In all other cases, the arguments are compared as floating-point (real) numbers. The following examples illustrate conversion of strings to numbers for comparison operations: mysql> SELECT 1 > '6x'; -> 0 mysql> SELECT 7 > '6x'; -> 1 mysql> SELECT 0 > 'x6'; -> 0 mysql> SELECT 0 = 'x6'; -> 1 For comparisons of a string column with a number, MySQL cannot use an index on the column to look up the value quickly. If STR_COL is an indexed string column, the index cannot be used when performing the lookup in the following statement: SELECT * FROM TBL_NAME WHERE STR_COL=1; The reason for this is that there are many different strings that may convert to the value `1', such as `'1'', `' 1'', or `'1a''. Comparisons that use floating-point numbers (or values that are converted to floating-point numbers) are approximate because such numbers are inexact. This might lead to results that appear inconsistent: mysql> SELECT '18015376320243458' = 18015376320243458; -> 1 mysql> SELECT '18015376320243459' = 18015376320243459; -> 0 Such results can occur because the values are converted to floating-point numbers, which have only 53 bits of precision and are subject to rounding: mysql> SELECT '18015376320243459'+0.0; -> 1.8015376320243e+16 Furthermore, the conversion from string to floating-point and from integer to floating-point do not necessarily occur the same way. The integer may be converted to floating-point by the CPU, whereas the string is converted digit by digit in an operation that involves floating-point multiplications. The results shown will vary on different systems, and can be affected by factors such as computer architecture or the compiler version or optimization level. One way to avoid such problems is to use `CAST()' so that a value will not be converted implicitly to a float-point number: mysql> SELECT CAST('18015376320243459' AS UNSIGNED) = 18015376320243459; -> 1 For more information about floating-point comparisons, see *Note problems-with-float::. Implicit conversion of a numeric or temporal value to a string produces a binary string (a *Note `BINARY': binary-varbinary, *Note `VARBINARY': binary-varbinary, or *Note `BLOB': blob. value). Such implicit conversions to string typically occur for functions that are passed numeric or temporal values when string values are more usual, and thus can have effects beyond the type of the converted value. Consider the expression `CONCAT(1, 'abc')'. The numeric argument `1' is converted to the binary string `'1'' and the concatenation of that value with the nonbinary string `'abc'' produces the binary string `'1abc''.  File: manual.info, Node: non-typed-operators, Next: control-flow-functions, Prev: type-conversion, Up: functions 12.3 Operators ============== * Menu: * operator-precedence:: Operator Precedence * comparison-operators:: Comparison Functions and Operators * logical-operators:: Logical Operators * assignment-operators:: Assignment Operators *Operators* Name Description `AND', `&&' Logical AND `=' Assign a value (as part of a *Note `SET': set-option. statement, or as part of the `SET' clause in an *Note `UPDATE': update. statement) `:=' Assign a value `BETWEEN ... AND ... ' Check whether a value is within a range of values `BINARY' Cast a string to a binary string `&' Bitwise AND `~' Invert bits `|' Bitwise OR `^' Bitwise XOR `CASE' Case operator `DIV' Integer division `/' Division operator `<=>' NULL-safe equal to operator `=' Equal operator `>=' Greater than or equal operator `>' Greater than operator `IS NOT NULL' NOT NULL value test `IS NOT' Test a value against a boolean `IS NULL' NULL value test `IS' Test a value against a boolean `<<' Left shift `<=' Less than or equal operator `<' Less than operator `LIKE' Simple pattern matching `-' Minus operator `%' Modulo operator `NOT BETWEEN ... AND ...' Check whether a value is not within a range of values `!=', `<>' Not equal operator `NOT LIKE' Negation of simple pattern matching `NOT REGEXP' Negation of REGEXP `NOT', `!' Negates value `||', `OR' Logical OR `+' Addition operator `REGEXP' Pattern matching using regular expressions `>>' Right shift `RLIKE' Synonym for REGEXP `SOUNDS LIKE' Compare sounds `*' Multiplication operator `-' Change the sign of the argument `XOR' Logical XOR  File: manual.info, Node: operator-precedence, Next: comparison-operators, Prev: non-typed-operators, Up: non-typed-operators 12.3.1 Operator Precedence -------------------------- Operator precedences are shown in the following list, from highest precedence to the lowest. Operators that are shown together on a line have the same precedence. INTERVAL BINARY, COLLATE ! - (unary minus), ~ (unary bit inversion) ^ *, /, DIV, %, MOD -, + <<, >> & | = (comparison), <=>, >=, >, <=, <, <>, !=, IS, LIKE, REGEXP, IN BETWEEN, CASE, WHEN, THEN, ELSE NOT &&, AND XOR ||, OR = (assignment), := The precedence of `=' depends on whether it is used as a comparison operator (`=') or as an assignment operator (`='). When used as a comparison operator, it has the same precedence as `<=>', `>=', `>', `<=', `<', `<>', `!=', `IS', `LIKE', `REGEXP', and `IN'. When used as an assignment operator, it has the same precedence as `:='. *Note set-option::, and *Note user-variables::, explain how MySQL determines which interpretation of `=' should apply. The meaning of some operators depends on the SQL mode: * By default, `||' is a logical `OR' operator. With `PIPES_AS_CONCAT' enabled, `||' is string concatenation, with a precedence between `^' and the unary operators. * By default, `!' has a higher precedence than `NOT'. With `HIGH_NOT_PRECEDENCE' enabled, `!' and `NOT' have the same precedence. See *Note server-sql-mode::. The precedence of operators determines the order of evaluation of terms in an expression. To override this order and group terms explicitly, use parentheses. For example: mysql> SELECT 1+2*3; -> 7 mysql> SELECT (1+2)*3; -> 9  File: manual.info, Node: comparison-operators, Next: logical-operators, Prev: operator-precedence, Up: non-typed-operators 12.3.2 Comparison Functions and Operators ----------------------------------------- *Comparison Operators* Name Description `BETWEEN ... AND ... ' Check whether a value is within a range of values `COALESCE()' Return the first non-NULL argument `<=>' NULL-safe equal to operator `=' Equal operator `>=' Greater than or equal operator `>' Greater than operator `GREATEST()' Return the largest argument `IN()' Check whether a value is within a set of values `INTERVAL()' Return the index of the argument that is less than the first argument `IS NOT NULL' NOT NULL value test `IS NOT' Test a value against a boolean `IS NULL' NULL value test `IS' Test a value against a boolean `ISNULL()' Test whether the argument is NULL `LEAST()' Return the smallest argument `<=' Less than or equal operator `<' Less than operator `LIKE' Simple pattern matching `NOT BETWEEN ... AND ...' Check whether a value is not within a range of values `!=', `<>' Not equal operator `NOT IN()' Check whether a value is not within a set of values `NOT LIKE' Negation of simple pattern matching `STRCMP()' Compare two strings Comparison operations result in a value of `1' (`TRUE'), `0' (`FALSE'), or `NULL'. These operations work for both numbers and strings. Strings are automatically converted to numbers and numbers to strings as necessary. The following relational comparison operators can be used to compare not only scalar operands, but row operands: = > < >= <= <> != For examples of row comparisons, see *Note row-subqueries::. Some of the functions in this section return values other than `1' (`TRUE'), `0' (`FALSE'), or `NULL'. For example, `LEAST()' and `GREATEST()'. However, the value they return is based on comparison operations performed according to the rules described in *Note type-conversion::. To convert a value to a specific type for comparison purposes, you can use the `CAST()' function. String values can be converted to a different character set using `CONVERT()'. See *Note cast-functions::. By default, string comparisons are not case sensitive and use the current character set. The default is `latin1' (cp1252 West European), which also works well for English. * `=' Equal: mysql> SELECT 1 = 0; -> 0 mysql> SELECT '0' = 0; -> 1 mysql> SELECT '0.0' = 0; -> 1 mysql> SELECT '0.01' = 0; -> 0 mysql> SELECT '.01' = 0.01; -> 1 * `<=>' `NULL'-safe equal. This operator performs an equality comparison like the `=' operator, but returns `1' rather than `NULL' if both operands are `NULL', and `0' rather than `NULL' if one operand is `NULL'. mysql> SELECT 1 <=> 1, NULL <=> NULL, 1 <=> NULL; -> 1, 1, 0 mysql> SELECT 1 = 1, NULL = NULL, 1 = NULL; -> 1, NULL, NULL * `<>', `!=' Not equal: mysql> SELECT '.01' <> '0.01'; -> 1 mysql> SELECT .01 <> '0.01'; -> 0 mysql> SELECT 'zapp' <> 'zappp'; -> 1 * `<=' Less than or equal: mysql> SELECT 0.1 <= 2; -> 1 * `<' Less than: mysql> SELECT 2 < 2; -> 0 * `>=' Greater than or equal: mysql> SELECT 2 >= 2; -> 1 * `>' Greater than: mysql> SELECT 2 > 2; -> 0 * `IS BOOLEAN_VALUE' Tests a value against a boolean value, where BOOLEAN_VALUE can be `TRUE', `FALSE', or `UNKNOWN'. mysql> SELECT 1 IS TRUE, 0 IS FALSE, NULL IS UNKNOWN; -> 1, 1, 1 * `IS NOT BOOLEAN_VALUE' Tests a value against a boolean value, where BOOLEAN_VALUE can be `TRUE', `FALSE', or `UNKNOWN'. mysql> SELECT 1 IS NOT UNKNOWN, 0 IS NOT UNKNOWN, NULL IS NOT UNKNOWN; -> 1, 1, 0 * `IS NULL' Tests whether a value is `NULL'. mysql> SELECT 1 IS NULL, 0 IS NULL, NULL IS NULL; -> 0, 0, 1 To work well with ODBC programs, MySQL supports the following extra features when using `IS NULL': * If `sql_auto_is_null' variable is set to 1 (the default), then after a statement that successfully inserts an automatically generated `AUTO_INCREMENT' value, you can find that value by issuing a statement of the following form: SELECT * FROM TBL_NAME WHERE AUTO_COL IS NULL If the statement returns a row, the value returned is the same as if you invoked the `LAST_INSERT_ID()' function. For details, including the return value after a multiple-row insert, see *Note information-functions::. If no `AUTO_INCREMENT' value was successfully inserted, the *Note `SELECT': select. statement returns no row. The behavior of retrieving an `AUTO_INCREMENT' value by using an `IS NULL' comparison can be disabled by setting `sql_auto_is_null = 0'. See *Note server-system-variables::. * For *Note `DATE': datetime. and *Note `DATETIME': datetime. columns that are declared as `NOT NULL', you can find the special date `'0000-00-00'' by using a statement like this: SELECT * FROM TBL_NAME WHERE DATE_COLUMN IS NULL This is needed to get some ODBC applications to work because ODBC does not support a `'0000-00-00'' date value. See *Note connector-odbc-usagenotes-functionality-last-insert-id::, and the description for the `FLAG_AUTO_IS_NULL' option at *Note connector-odbc-configuration-connection-parameters::. * `IS NOT NULL' Tests whether a value is not `NULL'. mysql> SELECT 1 IS NOT NULL, 0 IS NOT NULL, NULL IS NOT NULL; -> 1, 1, 0 * `EXPR BETWEEN MIN AND MAX' If EXPR is greater than or equal to MIN and EXPR is less than or equal to MAX, `BETWEEN' returns `1', otherwise it returns `0'. This is equivalent to the expression `(MIN <= EXPR AND EXPR <= MAX)' if all the arguments are of the same type. Otherwise type conversion takes place according to the rules described in *Note type-conversion::, but applied to all the three arguments. mysql> SELECT 2 BETWEEN 1 AND 3, 2 BETWEEN 3 and 1; -> 1, 0 mysql> SELECT 1 BETWEEN 2 AND 3; -> 0 mysql> SELECT 'b' BETWEEN 'a' AND 'c'; -> 1 mysql> SELECT 2 BETWEEN 2 AND '3'; -> 1 mysql> SELECT 2 BETWEEN 2 AND 'x-3'; -> 0 For best results when using `BETWEEN' with date or time values, use `CAST()' to explicitly convert the values to the desired data type. Examples: If you compare a *Note `DATETIME': datetime. to two *Note `DATE': datetime. values, convert the *Note `DATE': datetime. values to *Note `DATETIME': datetime. values. If you use a string constant such as `'2001-1-1'' in a comparison to a *Note `DATE': datetime, cast the string to a *Note `DATE': datetime. * `EXPR NOT BETWEEN MIN AND MAX' This is the same as `NOT (EXPR BETWEEN MIN AND MAX)'. * `COALESCE(VALUE,...)' Returns the first non-`NULL' value in the list, or `NULL' if there are no non-`NULL' values. mysql> SELECT COALESCE(NULL,1); -> 1 mysql> SELECT COALESCE(NULL,NULL,NULL); -> NULL * `GREATEST(VALUE1,VALUE2,...)' With two or more arguments, returns the largest (maximum-valued) argument. The arguments are compared using the same rules as for `LEAST()'. mysql> SELECT GREATEST(2,0); -> 2 mysql> SELECT GREATEST(34.0,3.0,5.0,767.0); -> 767.0 mysql> SELECT GREATEST('B','A','C'); -> 'C' `GREATEST()' returns `NULL' if any argument is `NULL'. * `EXPR IN (VALUE,...)' Returns `1' if EXPR is equal to any of the values in the `IN' list, else returns `0'. If all values are constants, they are evaluated according to the type of EXPR and sorted. The search for the item then is done using a binary search. This means `IN' is very quick if the `IN' value list consists entirely of constants. Otherwise, type conversion takes place according to the rules described in *Note type-conversion::, but applied to all the arguments. mysql> SELECT 2 IN (0,3,5,7); -> 0 mysql> SELECT 'wefwf' IN ('wee','wefwf','weg'); -> 1 You should never mix quoted and unquoted values in an `IN' list because the comparison rules for quoted values (such as strings) and unquoted values (such as numbers) differ. Mixing types may therefore lead to inconsistent results. For example, do not write an `IN' expression like this: SELECT val1 FROM tbl1 WHERE val1 IN (1,2,'a'); Instead, write it like this: SELECT val1 FROM tbl1 WHERE val1 IN ('1','2','a'); The number of values in the `IN' list is only limited by the `max_allowed_packet' value. To comply with the SQL standard, `IN' returns `NULL' not only if the expression on the left hand side is `NULL', but also if no match is found in the list and one of the expressions in the list is `NULL'. `IN()' syntax can also be used to write certain types of subqueries. See *Note any-in-some-subqueries::. * `EXPR NOT IN (VALUE,...)' This is the same as `NOT (EXPR IN (VALUE,...))'. * `ISNULL(EXPR)' If EXPR is `NULL', `ISNULL()' returns `1', otherwise it returns `0'. mysql> SELECT ISNULL(1+1); -> 0 mysql> SELECT ISNULL(1/0); -> 1 `ISNULL()' can be used instead of `=' to test whether a value is `NULL'. (Comparing a value to `NULL' using `=' always yields false.) The `ISNULL()' function shares some special behaviors with the `IS NULL' comparison operator. See the description of `IS NULL'. * `INTERVAL(N,N1,N2,N3,...)' Returns `0' if N < N1, `1' if N < N2 and so on or `-1' if N is `NULL'. All arguments are treated as integers. It is required that N1 < N2 < N3 < `...' < NN for this function to work correctly. This is because a binary search is used (very fast). mysql> SELECT INTERVAL(23, 1, 15, 17, 30, 44, 200); -> 3 mysql> SELECT INTERVAL(10, 1, 10, 100, 1000); -> 2 mysql> SELECT INTERVAL(22, 23, 30, 44, 200); -> 0 * `LEAST(VALUE1,VALUE2,...)' With two or more arguments, returns the smallest (minimum-valued) argument. The arguments are compared using the following rules: * If any argument is `NULL', the result is `NULL'. No comparison is needed. * If the return value is used in an *Note `INTEGER': numeric-types. context or all arguments are integer-valued, they are compared as integers. * If the return value is used in a *Note `REAL': numeric-types. context or all arguments are real-valued, they are compared as reals. * If the arguments comprise a mix of numbers and strings, they are compared as numbers. * If any argument is a nonbinary (character) string, the arguments are compared as nonbinary strings. * In all other cases, the arguments are compared as binary strings. mysql> SELECT LEAST(2,0); -> 0 mysql> SELECT LEAST(34.0,3.0,5.0,767.0); -> 3.0 mysql> SELECT LEAST('B','A','C'); -> 'A' Note that the preceding conversion rules can produce strange results in some borderline cases: mysql> SELECT CAST(LEAST(3600, 9223372036854775808.0) as SIGNED); -> -9223372036854775808 This happens because MySQL reads `9223372036854775808.0' in an integer context. The integer representation is not good enough to hold the value, so it wraps to a signed integer.  File: manual.info, Node: logical-operators, Next: assignment-operators, Prev: comparison-operators, Up: non-typed-operators 12.3.3 Logical Operators ------------------------ *Logical Operators* Name Description `AND', `&&' Logical AND `NOT', `!' Negates value `||', `OR' Logical OR `XOR' Logical XOR In SQL, all logical operators evaluate to `TRUE', `FALSE', or `NULL' (`UNKNOWN'). In MySQL, these are implemented as 1 (`TRUE'), 0 (`FALSE'), and `NULL'. Most of this is common to different SQL database servers, although some servers may return any nonzero value for `TRUE'. MySQL evaluates any nonzero, non-`NULL' value to `TRUE'. For example, the following statements all assess to `TRUE': mysql> SELECT 10 IS TRUE; -> 1 mysql> SELECT -10 IS TRUE; -> 1 mysql> SELECT 'string' IS NOT NULL; -> 1 * `NOT', `!' Logical NOT. Evaluates to `1' if the operand is `0', to `0' if the operand is nonzero, and `NOT NULL' returns `NULL'. mysql> SELECT NOT 10; -> 0 mysql> SELECT NOT 0; -> 1 mysql> SELECT NOT NULL; -> NULL mysql> SELECT ! (1+1); -> 0 mysql> SELECT ! 1+1; -> 1 The last example produces `1' because the expression evaluates the same way as `(!1)+1'. * `AND', `&&' Logical AND. Evaluates to `1' if all operands are nonzero and not `NULL', to `0' if one or more operands are `0', otherwise `NULL' is returned. mysql> SELECT 1 && 1; -> 1 mysql> SELECT 1 && 0; -> 0 mysql> SELECT 1 && NULL; -> NULL mysql> SELECT 0 && NULL; -> 0 mysql> SELECT NULL && 0; -> 0 * `OR', `||' Logical OR. When both operands are non-`NULL', the result is `1' if any operand is nonzero, and `0' otherwise. With a `NULL' operand, the result is `1' if the other operand is nonzero, and `NULL' otherwise. If both operands are `NULL', the result is `NULL'. mysql> SELECT 1 || 1; -> 1 mysql> SELECT 1 || 0; -> 1 mysql> SELECT 0 || 0; -> 0 mysql> SELECT 0 || NULL; -> NULL mysql> SELECT 1 || NULL; -> 1 * `XOR' Logical XOR. Returns `NULL' if either operand is `NULL'. For non-`NULL' operands, evaluates to `1' if an odd number of operands is nonzero, otherwise `0' is returned. mysql> SELECT 1 XOR 1; -> 0 mysql> SELECT 1 XOR 0; -> 1 mysql> SELECT 1 XOR NULL; -> NULL mysql> SELECT 1 XOR 1 XOR 1; -> 1 `a XOR b' is mathematically equal to `(a AND (NOT b)) OR ((NOT a) and b)'.  File: manual.info, Node: assignment-operators, Prev: logical-operators, Up: non-typed-operators 12.3.4 Assignment Operators --------------------------- *Assignment Operators* Name Description `=' Assign a value (as part of a *Note `SET': set-option. statement, or as part of the `SET' clause in an *Note `UPDATE': update. statement) `:=' Assign a value * `:=' Assignment operator. Causes the user variable on the left hand side of the operator to take on the value to its right. The value on the right hand side may be a literal value, another variable storing a value, or any legal expression that yields a scalar value, including the result of a query (provided that this value is a scalar value). You can perform multiple assignments in the same *Note `SET': set-option. statement. You can perform multiple assignments in the same statement- Unlike `=', the `:=' operator is never interpreted as a comparison operator. This means you can use `:=' in any valid SQL statement (not just in *Note `SET': set-option. statements) to assign a value to a variable. mysql> SELECT @var1, @var2; -> NULL, NULL mysql> SELECT @var1 := 1, @var2; -> 1, NULL mysql> SELECT @var1, @var2; -> 1, NULL mysql> SELECT @var1, @var2 := @var1; -> 1, 1 mysql> SELECT @var1, @var2; -> 1, 1 mysql> SELECT @var1:=COUNT(*) FROM t1; -> 4 mysql> SELECT @var1; -> 4 You can make value assignments using `:=' in other statements besides *Note `SELECT': select, such as *Note `UPDATE': update, as shown here: mysql> SELECT @var1; -> 4 mysql> SELECT * FROM t1; -> 1, 3, 5, 7 mysql> UPDATE t1 SET c1 = 2 WHERE c1 = @var1:= 1; Query OK, 1 row affected (0.00 sec) Rows matched: 1 Changed: 1 Warnings: 0 mysql> SELECT @var1; -> 1 mysql> SELECT * FROM t1; -> 2, 3, 5, 7 While it is also possible both to set and to read the value of the same variable in a single SQL statement using the `:=' operator, this is not recommended. *Note user-variables::, explains why you should avoid doing this. * `=' This operator is used to perform value assignments in two cases, described in the next two paragraphs. Within a *Note `SET': set-option. statement, `=' is treated as an assignment operator that causes the user variable on the left hand side of the operator to take on the value to its right. (In other words, when used in a *Note `SET': set-option. statement, `=' is treated identically to `:='.) The value on the right hand side may be a literal value, another variable storing a value, or any legal expression that yields a scalar value, including the result of a query (provided that this value is a scalar value). You can perform multiple assignments in the same *Note `SET': set-option. statement. In the `SET' clause of an *Note `UPDATE': update. statement, `=' also acts as an assignment operator; in this case, however, it causes the column named on the left hand side of the operator to assume the value given to the right, provided any `WHERE' conditions that are part of the *Note `UPDATE': update. are met. You can make multiple assignments in the same `SET' clause of an *Note `UPDATE': update. statement. In any other context, `=' is treated as a comparison operator. mysql> SELECT @var1, @var2; -> NULL, NULL mysql> SELECT @var1 := 1, @var2; -> 1, NULL mysql> SELECT @var1, @var2; -> 1, NULL mysql> SELECT @var1, @var2 := @var1; -> 1, 1 mysql> SELECT @var1, @var2; -> 1, 1 For more information, see *Note set-option::, *Note update::, and *Note subqueries::.  File: manual.info, Node: control-flow-functions, Next: string-functions, Prev: non-typed-operators, Up: functions 12.4 Control Flow Functions =========================== *Flow Control Operators* Name Description `CASE' Case operator `IF()' If/else construct `IFNULL()' Null if/else construct `NULLIF()' Return NULL if expr1 = expr2 * `CASE VALUE WHEN [COMPARE_VALUE] THEN RESULT [WHEN [COMPARE_VALUE] THEN RESULT ...] [ELSE RESULT] END' `CASE WHEN [CONDITION] THEN RESULT [WHEN [CONDITION] THEN RESULT ...] [ELSE RESULT] END' The first version returns the RESULT where `VALUE=COMPARE_VALUE'. The second version returns the result for the first condition that is true. If there was no matching result value, the result after `ELSE' is returned, or `NULL' if there is no `ELSE' part. mysql> SELECT CASE 1 WHEN 1 THEN 'one' -> WHEN 2 THEN 'two' ELSE 'more' END; -> 'one' mysql> SELECT CASE WHEN 1>0 THEN 'true' ELSE 'false' END; -> 'true' mysql> SELECT CASE BINARY 'B' -> WHEN 'a' THEN 1 WHEN 'b' THEN 2 END; -> NULL The return type of a `CASE' expression is the compatible aggregated type of all return values, but also depends on the context in which it is used. If used in a string context, the result is returned as a string. If used in a numeric context, the result is returned as a decimal, real, or integer value. *Note*: The syntax of the `CASE' _expression_ shown here differs slightly from that of the SQL *Note `CASE': case-statement. _statement_ described in *Note case-statement::, for use inside stored programs. The *Note `CASE': case-statement. statement cannot have an `ELSE NULL' clause, and it is terminated with `END CASE' instead of `END'. * `IF(EXPR1,EXPR2,EXPR3)' If EXPR1 is `TRUE' (`EXPR1 <> 0' and `EXPR1 <> NULL') then `IF()' returns EXPR2; otherwise it returns EXPR3. `IF()' returns a numeric or string value, depending on the context in which it is used. mysql> SELECT IF(1>2,2,3); -> 3 mysql> SELECT IF(1<2,'yes','no'); -> 'yes' mysql> SELECT IF(STRCMP('test','test1'),'no','yes'); -> 'no' If only one of EXPR2 or EXPR3 is explicitly `NULL', the result type of the `IF()' function is the type of the non-`NULL' expression. The default return type of `IF()' (which may matter when it is stored into a temporary table) is calculated as follows. Expression Return Value EXPR2 or EXPR3 returns a string string EXPR2 or EXPR3 returns a floating-point floating-point value EXPR2 or EXPR3 returns an integer integer If EXPR2 and EXPR3 are both strings, the result is case sensitive if either string is case sensitive. *Note*: There is also an *Note `IF': if-statement. _statement_, which differs from the `IF()' _function_ described here. See *Note if-statement::. * `IFNULL(EXPR1,EXPR2)' If EXPR1 is not `NULL', `IFNULL()' returns EXPR1; otherwise it returns EXPR2. `IFNULL()' returns a numeric or string value, depending on the context in which it is used. mysql> SELECT IFNULL(1,0); -> 1 mysql> SELECT IFNULL(NULL,10); -> 10 mysql> SELECT IFNULL(1/0,10); -> 10 mysql> SELECT IFNULL(1/0,'yes'); -> 'yes' The default result value of `IFNULL(EXPR1,EXPR2)' is the more `general' of the two expressions, in the order `STRING', *Note `REAL': numeric-types, or *Note `INTEGER': numeric-types. Consider the case of a table based on expressions or where MySQL must internally store a value returned by `IFNULL()' in a temporary table: mysql> CREATE TABLE tmp SELECT IFNULL(1,'test') AS test; mysql> DESCRIBE tmp; +-------+--------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +-------+--------------+------+-----+---------+-------+ | test | varbinary(4) | NO | | | | +-------+--------------+------+-----+---------+-------+ In this example, the type of the `test' column is *Note `VARBINARY(4)': binary-varbinary. * `NULLIF(EXPR1,EXPR2)' Returns `NULL' if `EXPR1 = EXPR2' is true, otherwise returns EXPR1. This is the same as `CASE WHEN EXPR1 = EXPR2 THEN NULL ELSE EXPR1 END'. mysql> SELECT NULLIF(1,1); -> NULL mysql> SELECT NULLIF(1,2); -> 1 Note that MySQL evaluates EXPR1 twice if the arguments are not equal.  File: manual.info, Node: string-functions, Next: numeric-functions, Prev: control-flow-functions, Up: functions 12.5 String Functions ===================== * Menu: * string-comparison-functions:: String Comparison Functions * regexp:: Regular Expressions *String Operators* Name Description `ASCII()' Return numeric value of left-most character `BIN()' Return a string representation of the argument `BIT_LENGTH()' Return length of argument in bits `CHAR_LENGTH()' Return number of characters in argument `CHAR()' Return the character for each integer passed `CHARACTER_LENGTH()' A synonym for CHAR_LENGTH() `CONCAT_WS()' Return concatenate with separator `CONCAT()' Return concatenated string `ELT()' Return string at index number `EXPORT_SET()' Return a string such that for every bit set in the value bits, you get an on string and for every unset bit, you get an off string `FIELD()' Return the index (position) of the first argument in the subsequent arguments `FIND_IN_SET()' Return the index position of the first argument within the second argument `FORMAT()' Return a number formatted to specified number of decimal places `HEX()' Return a hexadecimal representation of a decimal or string value `INSERT()' Insert a substring at the specified position up to the specified number of characters `INSTR()' Return the index of the first occurrence of substring `LCASE()' Synonym for LOWER() `LEFT()' Return the leftmost number of characters as specified `LENGTH()' Return the length of a string in bytes `LIKE' Simple pattern matching `LOAD_FILE()' Load the named file `LOCATE()' Return the position of the first occurrence of substring `LOWER()' Return the argument in lowercase `LPAD()' Return the string argument, left-padded with the specified string `LTRIM()' Remove leading spaces `MAKE_SET()' Return a set of comma-separated strings that have the corresponding bit in bits set `MATCH' Perform full-text search `MID()' Return a substring starting from the specified position `NOT LIKE' Negation of simple pattern matching `NOT REGEXP' Negation of REGEXP `OCTET_LENGTH()' A synonym for LENGTH() `ORD()' Return character code for leftmost character of the argument `POSITION()' A synonym for LOCATE() `QUOTE()' Escape the argument for use in an SQL statement `REGEXP' Pattern matching using regular expressions `REPEAT()' Repeat a string the specified number of times `REPLACE()' Replace occurrences of a specified string `REVERSE()' Reverse the characters in a string `RIGHT()' Return the specified rightmost number of characters `RLIKE' Synonym for REGEXP `RPAD()' Append string the specified number of times `RTRIM()' Remove trailing spaces `SOUNDEX()' Return a soundex string `SOUNDS LIKE' Compare sounds `SPACE()' Return a string of the specified number of spaces `STRCMP()' Compare two strings `SUBSTR()' Return the substring as specified `SUBSTRING_INDEX()' Return a substring from a string before the specified number of occurrences of the delimiter `SUBSTRING()' Return the substring as specified `TRIM()' Remove leading and trailing spaces `UCASE()' Synonym for UPPER() `UNHEX()' Convert each pair of hexadecimal digits to a character `UPPER()' Convert to uppercase String-valued functions return `NULL' if the length of the result would be greater than the value of the `max_allowed_packet' system variable. See *Note server-parameters::. For functions that operate on string positions, the first position is numbered 1. For functions that take length arguments, noninteger arguments are rounded to the nearest integer. * `ASCII(STR)' Returns the numeric value of the leftmost character of the string STR. Returns `0' if STR is the empty string. Returns `NULL' if STR is `NULL'. `ASCII()' works for 8-bit characters. mysql> SELECT ASCII('2'); -> 50 mysql> SELECT ASCII(2); -> 50 mysql> SELECT ASCII('dx'); -> 100 See also the `ORD()' function. * `BIN(N)' Returns a string representation of the binary value of N, where N is a longlong (*Note `BIGINT': numeric-types.) number. This is equivalent to `CONV(N,10,2)'. Returns `NULL' if N is `NULL'. mysql> SELECT BIN(12); -> '1100' * `BIT_LENGTH(STR)' Returns the length of the string STR in bits. mysql> SELECT BIT_LENGTH('text'); -> 32 * `CHAR(N,... [USING CHARSET_NAME])' `CHAR()' interprets each argument N as an integer and returns a string consisting of the characters given by the code values of those integers. `NULL' values are skipped. mysql> SELECT CHAR(77,121,83,81,'76'); -> 'MySQL' mysql> SELECT CHAR(77,77.3,'77.3'); -> 'MMM' `CHAR()' arguments larger than 255 are converted into multiple result bytes. For example, `CHAR(256)' is equivalent to `CHAR(1,0)', and `CHAR(256*256)' is equivalent to `CHAR(1,0,0)': mysql> SELECT HEX(CHAR(1,0)), HEX(CHAR(256)); +----------------+----------------+ | HEX(CHAR(1,0)) | HEX(CHAR(256)) | +----------------+----------------+ | 0100 | 0100 | +----------------+----------------+ mysql> SELECT HEX(CHAR(1,0,0)), HEX(CHAR(256*256)); +------------------+--------------------+ | HEX(CHAR(1,0,0)) | HEX(CHAR(256*256)) | +------------------+--------------------+ | 010000 | 010000 | +------------------+--------------------+ By default, `CHAR()' returns a binary string. To produce a string in a given character set, use the optional `USING' clause: mysql> SELECT CHARSET(CHAR(0x65)), CHARSET(CHAR(0x65 USING utf8)); +---------------------+--------------------------------+ | CHARSET(CHAR(0x65)) | CHARSET(CHAR(0x65 USING utf8)) | +---------------------+--------------------------------+ | binary | utf8 | +---------------------+--------------------------------+ If `USING' is given and the result string is illegal for the given character set, a warning is issued. Also, if strict SQL mode is enabled, the result from `CHAR()' becomes `NULL'. * `CHAR_LENGTH(STR)' Returns the length of the string STR, measured in characters. A multi-byte character counts as a single character. This means that for a string containing five two-byte characters, `LENGTH()' returns `10', whereas `CHAR_LENGTH()' returns `5'. * `CHARACTER_LENGTH(STR)' `CHARACTER_LENGTH()' is a synonym for `CHAR_LENGTH()'. * `CONCAT(STR1,STR2,...)' Returns the string that results from concatenating the arguments. May have one or more arguments. If all arguments are nonbinary strings, the result is a nonbinary string. If the arguments include any binary strings, the result is a binary string. A numeric argument is converted to its equivalent binary string form; if you want to avoid that, you can use an explicit type cast, as in this example: SELECT CONCAT(CAST(INT_COL AS CHAR), CHAR_COL); `CONCAT()' returns `NULL' if any argument is `NULL'. mysql> SELECT CONCAT('My', 'S', 'QL'); -> 'MySQL' mysql> SELECT CONCAT('My', NULL, 'QL'); -> NULL mysql> SELECT CONCAT(14.3); -> '14.3' For quoted strings, concatenation can be performed by placing the strings next to each other: mysql> SELECT 'My' 'S' 'QL'; -> 'MySQL' * `CONCAT_WS(SEPARATOR,STR1,STR2,...)' `CONCAT_WS()' stands for Concatenate With Separator and is a special form of `CONCAT()'. The first argument is the separator for the rest of the arguments. The separator is added between the strings to be concatenated. The separator can be a string, as can the rest of the arguments. If the separator is `NULL', the result is `NULL'. mysql> SELECT CONCAT_WS(',','First name','Second name','Last Name'); -> 'First name,Second name,Last Name' mysql> SELECT CONCAT_WS(',','First name',NULL,'Last Name'); -> 'First name,Last Name' `CONCAT_WS()' does not skip empty strings. However, it does skip any `NULL' values after the separator argument. * `ELT(N,STR1,STR2,STR3,...)' Returns STR1 if N = `1', STR2 if N = `2', and so on. Returns `NULL' if N is less than `1' or greater than the number of arguments. `ELT()' is the complement of `FIELD()'. mysql> SELECT ELT(1, 'ej', 'Heja', 'hej', 'foo'); -> 'ej' mysql> SELECT ELT(4, 'ej', 'Heja', 'hej', 'foo'); -> 'foo' * `EXPORT_SET(BITS,ON,OFF[,SEPARATOR[,NUMBER_OF_BITS]])' Returns a string such that for every bit set in the value BITS, you get an ON string and for every bit not set in the value, you get an OFF string. Bits in BITS are examined from right to left (from low-order to high-order bits). Strings are added to the result from left to right, separated by the SEPARATOR string (the default being the comma character ``,''). The number of bits examined is given by NUMBER_OF_BITS, which has a default of 64 if not specified. NUMBER_OF_BITS is silently clipped to 64 if larger than 64. It is treated as an unsigned integer, so a value of -1 is effectively the same as 64. mysql> SELECT EXPORT_SET(5,'Y','N',',',4); -> 'Y,N,Y,N' mysql> SELECT EXPORT_SET(6,'1','0',',',10); -> '0,1,1,0,0,0,0,0,0,0' * `FIELD(STR,STR1,STR2,STR3,...)' Returns the index (position) of STR in the STR1, STR2, STR3, `...' list. Returns `0' if STR is not found. If all arguments to `FIELD()' are strings, all arguments are compared as strings. If all arguments are numbers, they are compared as numbers. Otherwise, the arguments are compared as double. If STR is `NULL', the return value is `0' because `NULL' fails equality comparison with any value. `FIELD()' is the complement of `ELT()'. mysql> SELECT FIELD('ej', 'Hej', 'ej', 'Heja', 'hej', 'foo'); -> 2 mysql> SELECT FIELD('fo', 'Hej', 'ej', 'Heja', 'hej', 'foo'); -> 0 * `FIND_IN_SET(STR,STRLIST)' Returns a value in the range of 1 to N if the string STR is in the string list STRLIST consisting of N substrings. A string list is a string composed of substrings separated by ``,'' characters. If the first argument is a constant string and the second is a column of type *Note `SET': set, the `FIND_IN_SET()' function is optimized to use bit arithmetic. Returns `0' if STR is not in STRLIST or if STRLIST is the empty string. Returns `NULL' if either argument is `NULL'. This function does not work properly if the first argument contains a comma (``,'') character. mysql> SELECT FIND_IN_SET('b','a,b,c,d'); -> 2 * `FORMAT(X,D)' Formats the number X to a format like `'#,###,###.##'', rounded to D decimal places, and returns the result as a string. If D is `0', the result has no decimal point or fractional part. mysql> SELECT FORMAT(12332.123456, 4); -> '12,332.1235' mysql> SELECT FORMAT(12332.1,4); -> '12,332.1000' mysql> SELECT FORMAT(12332.2,0); -> '12,332' * `HEX(STR)', `HEX(N)' For a string argument STR, `HEX()' returns a hexadecimal string representation of STR where each character in STR is converted to two hexadecimal digits. The inverse of this operation is performed by the `UNHEX()' function. For a numeric argument N, `HEX()' returns a hexadecimal string representation of the value of N treated as a longlong (*Note `BIGINT': numeric-types.) number. This is equivalent to `CONV(N,10,16)'. The inverse of this operation is performed by `CONV(HEX(N),16,10)'. mysql> SELECT 0x616263, HEX('abc'), UNHEX(HEX('abc')); -> 'abc', 616263, 'abc' mysql> SELECT HEX(255), CONV(HEX(255),16,10); -> 'FF', 255 * `INSERT(STR,POS,LEN,NEWSTR)' Returns the string STR, with the substring beginning at position POS and LEN characters long replaced by the string NEWSTR. Returns the original string if POS is not within the length of the string. Replaces the rest of the string from position POS if LEN is not within the length of the rest of the string. Returns `NULL' if any argument is `NULL'. mysql> SELECT INSERT('Quadratic', 3, 4, 'What'); -> 'QuWhattic' mysql> SELECT INSERT('Quadratic', -1, 4, 'What'); -> 'Quadratic' mysql> SELECT INSERT('Quadratic', 3, 100, 'What'); -> 'QuWhat' This function is multi-byte safe. * `INSTR(STR,SUBSTR)' Returns the position of the first occurrence of substring SUBSTR in string STR. This is the same as the two-argument form of `LOCATE()', except that the order of the arguments is reversed. mysql> SELECT INSTR('foobarbar', 'bar'); -> 4 mysql> SELECT INSTR('xbar', 'foobar'); -> 0 This function is multi-byte safe, and is case sensitive only if at least one argument is a binary string. * `LCASE(STR)' `LCASE()' is a synonym for `LOWER()'. * `LEFT(STR,LEN)' Returns the leftmost LEN characters from the string STR, or `NULL' if any argument is `NULL'. mysql> SELECT LEFT('foobarbar', 5); -> 'fooba' * `LENGTH(STR)' Returns the length of the string STR, measured in bytes. A multi-byte character counts as multiple bytes. This means that for a string containing five two-byte characters, `LENGTH()' returns `10', whereas `CHAR_LENGTH()' returns `5'. mysql> SELECT LENGTH('text'); -> 4 * `LOAD_FILE(FILE_NAME)' Reads the file and returns the file contents as a string. To use this function, the file must be located on the server host, you must specify the full path name to the file, and you must have the `FILE' privilege. The file must be readable by all and its size less than `max_allowed_packet' bytes. If the `secure_file_priv' system variable is set to a nonempty directory name, the file to be loaded must be located in that directory. If the file does not exist or cannot be read because one of the preceding conditions is not satisfied, the function returns `NULL'. As of MySQL 5.1.6, the `character_set_filesystem' system variable controls interpretation of file names that are given as literal strings. mysql> UPDATE t SET blob_col=LOAD_FILE('/tmp/picture') WHERE id=1; * `LOCATE(SUBSTR,STR)', `LOCATE(SUBSTR,STR,POS)' The first syntax returns the position of the first occurrence of substring SUBSTR in string STR. The second syntax returns the position of the first occurrence of substring SUBSTR in string STR, starting at position POS. Returns `0' if SUBSTR is not in STR. mysql> SELECT LOCATE('bar', 'foobarbar'); -> 4 mysql> SELECT LOCATE('xbar', 'foobar'); -> 0 mysql> SELECT LOCATE('bar', 'foobarbar', 5); -> 7 This function is multi-byte safe, and is case-sensitive only if at least one argument is a binary string. * `LOWER(STR)' Returns the string STR with all characters changed to lowercase according to the current character set mapping. The default is `latin1' (cp1252 West European). mysql> SELECT LOWER('QUADRATICALLY'); -> 'quadratically' `LOWER()' (and `UPPER()') are ineffective when applied to binary strings (*Note `BINARY': binary-varbinary, *Note `VARBINARY': binary-varbinary, *Note `BLOB': blob.). To perform lettercase conversion, convert the string to a nonbinary string: mysql> SET @str = BINARY 'New York'; mysql> SELECT LOWER(@str), LOWER(CONVERT(@str USING latin1)); +-------------+-----------------------------------+ | LOWER(@str) | LOWER(CONVERT(@str USING latin1)) | +-------------+-----------------------------------+ | New York | new york | +-------------+-----------------------------------+ This function is multi-byte safe. * `LPAD(STR,LEN,PADSTR)' Returns the string STR, left-padded with the string PADSTR to a length of LEN characters. If STR is longer than LEN, the return value is shortened to LEN characters. mysql> SELECT LPAD('hi',4,'??'); -> '??hi' mysql> SELECT LPAD('hi',1,'??'); -> 'h' * `LTRIM(STR)' Returns the string STR with leading space characters removed. mysql> SELECT LTRIM(' barbar'); -> 'barbar' This function is multi-byte safe. * `MAKE_SET(BITS,STR1,STR2,...)' Returns a set value (a string containing substrings separated by ``,'' characters) consisting of the strings that have the corresponding bit in BITS set. STR1 corresponds to bit 0, STR2 to bit 1, and so on. `NULL' values in STR1, STR2, `...' are not appended to the result. mysql> SELECT MAKE_SET(1,'a','b','c'); -> 'a' mysql> SELECT MAKE_SET(1 | 4,'hello','nice','world'); -> 'hello,world' mysql> SELECT MAKE_SET(1 | 4,'hello','nice',NULL,'world'); -> 'hello' mysql> SELECT MAKE_SET(0,'a','b','c'); -> '' * `MID(STR,POS,LEN)' `MID(STR,POS,LEN)' is a synonym for `SUBSTRING(STR,POS,LEN)'. * `OCTET_LENGTH(STR)' `OCTET_LENGTH()' is a synonym for `LENGTH()'. * `ORD(STR)' If the leftmost character of the string STR is a multi-byte character, returns the code for that character, calculated from the numeric values of its constituent bytes using this formula: (1st byte code) + (2nd byte code * 256) + (3rd byte code * 256^2) ... If the leftmost character is not a multi-byte character, `ORD()' returns the same value as the `ASCII()' function. mysql> SELECT ORD('2'); -> 50 * `POSITION(SUBSTR IN STR)' `POSITION(SUBSTR IN STR)' is a synonym for `LOCATE(SUBSTR,STR)'. * `QUOTE(STR)' Quotes a string to produce a result that can be used as a properly escaped data value in an SQL statement. The string is returned enclosed by single quotation marks and with each instance of single quote (``'''), backslash (``\''), ASCII `NUL', and Control+Z preceded by a backslash. If the argument is `NULL', the return value is the word `NULL' without enclosing single quotation marks. mysql> SELECT QUOTE('Don\'t!'); -> 'Don\'t!' mysql> SELECT QUOTE(NULL); -> NULL * `REPEAT(STR,COUNT)' Returns a string consisting of the string STR repeated COUNT times. If COUNT is less than 1, returns an empty string. Returns `NULL' if STR or COUNT are `NULL'. mysql> SELECT REPEAT('MySQL', 3); -> 'MySQLMySQLMySQL' * `REPLACE(STR,FROM_STR,TO_STR)' Returns the string STR with all occurrences of the string FROM_STR replaced by the string TO_STR. `REPLACE()' performs a case-sensitive match when searching for FROM_STR. mysql> SELECT REPLACE('www.mysql.com', 'w', 'Ww'); -> 'WwWwWw.mysql.com' This function is multi-byte safe. * `REVERSE(STR)' Returns the string STR with the order of the characters reversed. mysql> SELECT REVERSE('abc'); -> 'cba' This function is multi-byte safe. * `RIGHT(STR,LEN)' Returns the rightmost LEN characters from the string STR, or `NULL' if any argument is `NULL'. mysql> SELECT RIGHT('foobarbar', 4); -> 'rbar' This function is multi-byte safe. * `RPAD(STR,LEN,PADSTR)' Returns the string STR, right-padded with the string PADSTR to a length of LEN characters. If STR is longer than LEN, the return value is shortened to LEN characters. mysql> SELECT RPAD('hi',5,'?'); -> 'hi???' mysql> SELECT RPAD('hi',1,'?'); -> 'h' This function is multi-byte safe. * `RTRIM(STR)' Returns the string STR with trailing space characters removed. mysql> SELECT RTRIM('barbar '); -> 'barbar' This function is multi-byte safe. * `SOUNDEX(STR)' Returns a soundex string from STR. Two strings that sound almost the same should have identical soundex strings. A standard soundex string is four characters long, but the `SOUNDEX()' function returns an arbitrarily long string. You can use `SUBSTRING()' on the result to get a standard soundex string. All nonalphabetic characters in STR are ignored. All international alphabetic characters outside the A-Z range are treated as vowels. *Important*: When using `SOUNDEX()', you should be aware of the following limitations: * This function, as currently implemented, is intended to work well with strings that are in the English language only. Strings in other languages may not produce reliable results. * This function is not guaranteed to provide consistent results with strings that use multi-byte character sets, including `utf-8'. We hope to remove these limitations in a future release. See Bug#22638 for more information. mysql> SELECT SOUNDEX('Hello'); -> 'H400' mysql> SELECT SOUNDEX('Quadratically'); -> 'Q36324' *Note*: This function implements the original Soundex algorithm, not the more popular enhanced version (also described by D. Knuth). The difference is that original version discards vowels first and duplicates second, whereas the enhanced version discards duplicates first and vowels second. * `EXPR1 SOUNDS LIKE EXPR2' This is the same as `SOUNDEX(EXPR1) = SOUNDEX(EXPR2)'. * `SPACE(N)' Returns a string consisting of N space characters. mysql> SELECT SPACE(6); -> ' ' * `SUBSTR(STR,POS)', `SUBSTR(STR FROM POS)', `SUBSTR(STR,POS,LEN)', `SUBSTR(STR FROM POS FOR LEN)' `SUBSTR()' is a synonym for `SUBSTRING()'. * `SUBSTRING(STR,POS)', `SUBSTRING(STR FROM POS)', `SUBSTRING(STR,POS,LEN)', `SUBSTRING(STR FROM POS FOR LEN)' The forms without a LEN argument return a substring from string STR starting at position POS. The forms with a LEN argument return a substring LEN characters long from string STR, starting at position POS. The forms that use `FROM' are standard SQL syntax. It is also possible to use a negative value for POS. In this case, the beginning of the substring is POS characters from the end of the string, rather than the beginning. A negative value may be used for POS in any of the forms of this function. For all forms of `SUBSTRING()', the position of the first character in the string from which the substring is to be extracted is reckoned as `1'. mysql> SELECT SUBSTRING('Quadratically',5); -> 'ratically' mysql> SELECT SUBSTRING('foobarbar' FROM 4); -> 'barbar' mysql> SELECT SUBSTRING('Quadratically',5,6); -> 'ratica' mysql> SELECT SUBSTRING('Sakila', -3); -> 'ila' mysql> SELECT SUBSTRING('Sakila', -5, 3); -> 'aki' mysql> SELECT SUBSTRING('Sakila' FROM -4 FOR 2); -> 'ki' This function is multi-byte safe. If LEN is less than 1, the result is the empty string. * `SUBSTRING_INDEX(STR,DELIM,COUNT)' Returns the substring from string STR before COUNT occurrences of the delimiter DELIM. If COUNT is positive, everything to the left of the final delimiter (counting from the left) is returned. If COUNT is negative, everything to the right of the final delimiter (counting from the right) is returned. `SUBSTRING_INDEX()' performs a case-sensitive match when searching for DELIM. mysql> SELECT SUBSTRING_INDEX('www.mysql.com', '.', 2); -> 'www.mysql' mysql> SELECT SUBSTRING_INDEX('www.mysql.com', '.', -2); -> 'mysql.com' This function is multi-byte safe. * `TRIM([{BOTH | LEADING | TRAILING} [REMSTR] FROM] STR)', `TRIM([REMSTR FROM] STR)' Returns the string STR with all REMSTR prefixes or suffixes removed. If none of the specifiers `BOTH', `LEADING', or `TRAILING' is given, `BOTH' is assumed. REMSTR is optional and, if not specified, spaces are removed. mysql> SELECT TRIM(' bar '); -> 'bar' mysql> SELECT TRIM(LEADING 'x' FROM 'xxxbarxxx'); -> 'barxxx' mysql> SELECT TRIM(BOTH 'x' FROM 'xxxbarxxx'); -> 'bar' mysql> SELECT TRIM(TRAILING 'xyz' FROM 'barxxyz'); -> 'barx' This function is multi-byte safe. * `UCASE(STR)' `UCASE()' is a synonym for `UPPER()'. * `UNHEX(STR)' For a string argument STR, `UNHEX(STR)' performs the inverse operation of `HEX(STR)'. That is, it interprets each pair of characters in the argument as a hexadecimal number and converts it to the character represented by the number. The return value is a binary string. mysql> SELECT UNHEX('4D7953514C'); -> 'MySQL' mysql> SELECT 0x4D7953514C; -> 'MySQL' mysql> SELECT UNHEX(HEX('string')); -> 'string' mysql> SELECT HEX(UNHEX('1267')); -> '1267' The characters in the argument string must be legal hexadecimal digits: `'0'' .. `'9'', `'A'' .. `'F'', `'a'' .. `'f''. If the argument contains any nonhexadecimal digits, the result is `NULL': mysql> SELECT UNHEX('GG'); +-------------+ | UNHEX('GG') | +-------------+ | NULL | +-------------+ A `NULL' result can occur if the argument to `UNHEX()' is a *Note `BINARY': binary-varbinary. column, because values are padded with 0x00 bytes when stored but those bytes are not stripped on retrieval. For example, `'41'' is stored into a `CHAR(3)' column as `'41 '' and retrieved as `'41'' (with the trailing pad space stripped), so `UNHEX()' for the column value returns `'A''. By contrast `'41'' is stored into a `BINARY(3)' column as `'41\0'' and retrieved as `'41\0'' (with the trailing pad `0x00' byte not stripped). `'\0'' is not a legal hexadecimal digit, so `UNHEX()' for the column value returns `NULL'. For a numeric argument N, the inverse of `HEX(N)' is not performed by `UNHEX()'. Use `CONV(HEX(N),16,10)' instead. See the description of `HEX()'. * `UPPER(STR)' Returns the string STR with all characters changed to uppercase according to the current character set mapping. The default is `latin1' (cp1252 West European). mysql> SELECT UPPER('Hej'); -> 'HEJ' See the description of `LOWER()' for information that also applies to `UPPER()', such as information about how to perform lettercase conversion of binary strings (*Note `BINARY': binary-varbinary, *Note `VARBINARY': binary-varbinary, *Note `BLOB': blob.) for which these functions are ineffective. This function is multi-byte safe.  File: manual.info, Node: string-comparison-functions, Next: regexp, Prev: string-functions, Up: string-functions 12.5.1 String Comparison Functions ---------------------------------- *String Comparison Operators* Name Description `LIKE' Simple pattern matching `NOT LIKE' Negation of simple pattern matching `STRCMP()' Compare two strings If a string function is given a binary string as an argument, the resulting string is also a binary string. A number converted to a string is treated as a binary string. This affects only comparisons. Normally, if any expression in a string comparison is case sensitive, the comparison is performed in case-sensitive fashion. * `EXPR LIKE PAT [ESCAPE 'ESCAPE_CHAR']' Pattern matching using SQL simple regular expression comparison. Returns `1' (`TRUE') or `0' (`FALSE'). If either EXPR or PAT is `NULL', the result is `NULL'. The pattern need not be a literal string. For example, it can be specified as a string expression or table column. Per the SQL standard, `LIKE' performs matching on a per-character basis, thus it can produce results different from the `=' comparison operator: mysql> SELECT 'a"' LIKE 'ae' COLLATE latin1_german2_ci; +-----------------------------------------+ | 'a"' LIKE 'ae' COLLATE latin1_german2_ci | +-----------------------------------------+ | 0 | +-----------------------------------------+ mysql> SELECT 'a"' = 'ae' COLLATE latin1_german2_ci; +--------------------------------------+ | 'a"' = 'ae' COLLATE latin1_german2_ci | +--------------------------------------+ | 1 | +--------------------------------------+ In particular, trailing spaces are significant, which is not true for *Note `CHAR': char. or *Note `VARCHAR': char. comparisons performed with the `=' operator: mysql> SELECT 'a' = 'a ', 'a' LIKE 'a '; +------------+---------------+ | 'a' = 'a ' | 'a' LIKE 'a ' | +------------+---------------+ | 1 | 0 | +------------+---------------+ 1 row in set (0.00 sec) With `LIKE' you can use the following two wildcard characters in the pattern. Character Description `%' Matches any number of characters, even zero characters `_' Matches exactly one character mysql> SELECT 'David!' LIKE 'David_'; -> 1 mysql> SELECT 'David!' LIKE '%D%v%'; -> 1 To test for literal instances of a wildcard character, precede it by the escape character. If you do not specify the `ESCAPE' character, ``\'' is assumed. String Description `\%' Matches one ``%'' character `\_' Matches one ``_'' character mysql> SELECT 'David!' LIKE 'David\_'; -> 0 mysql> SELECT 'David_' LIKE 'David\_'; -> 1 To specify a different escape character, use the `ESCAPE' clause: mysql> SELECT 'David_' LIKE 'David|_' ESCAPE '|'; -> 1 The escape sequence should be empty or one character long. The expression must evaluate as a constant at execution time. As of MySQL 5.1.2, if the `NO_BACKSLASH_ESCAPES' SQL mode is enabled, the sequence cannot be empty. The following two statements illustrate that string comparisons are not case sensitive unless one of the operands is a binary string: mysql> SELECT 'abc' LIKE 'ABC'; -> 1 mysql> SELECT 'abc' LIKE BINARY 'ABC'; -> 0 In MySQL, `LIKE' is permitted on numeric expressions. (This is an extension to the standard SQL `LIKE'.) mysql> SELECT 10 LIKE '1%'; -> 1 *Note*: Because MySQL uses C escape syntax in strings (for example, ``\n'' to represent a newline character), you must double any ``\'' that you use in `LIKE' strings. For example, to search for ``\n'', specify it as ``\\n''. To search for ``\'', specify it as ``\\\\''; this is because the backslashes are stripped once by the parser and again when the pattern match is made, leaving a single backslash to be matched against. Exception: At the end of the pattern string, backslash can be specified as ``\\''. At the end of the string, backslash stands for itself because there is nothing following to escape. Suppose that a table contains the following values: mysql> SELECT filename FROM t1; +--------------+ | filename | +--------------+ | C: | | C:\ | | C:\Programs | | C:\Programs\ | +--------------+ To test for values that end with backslash, you can match the values using either of the following patterns: mysql> SELECT filename, filename LIKE '%\\' FROM t1; +--------------+---------------------+ | filename | filename LIKE '%\\' | +--------------+---------------------+ | C: | 0 | | C:\ | 1 | | C:\Programs | 0 | | C:\Programs\ | 1 | +--------------+---------------------+ mysql> SELECT filename, filename LIKE '%\\\\' FROM t1; +--------------+-----------------------+ | filename | filename LIKE '%\\\\' | +--------------+-----------------------+ | C: | 0 | | C:\ | 1 | | C:\Programs | 0 | | C:\Programs\ | 1 | +--------------+-----------------------+ * `EXPR NOT LIKE PAT [ESCAPE 'ESCAPE_CHAR']' This is the same as `NOT (EXPR LIKE PAT [ESCAPE 'ESCAPE_CHAR'])'. *Note*: Aggregate queries involving `NOT LIKE' comparisons with columns containing `NULL' may yield unexpected results. For example, consider the following table and data: CREATE TABLE foo (bar VARCHAR(10)); INSERT INTO foo VALUES (NULL), (NULL); The query `SELECT COUNT(*) FROM foo WHERE bar LIKE '%baz%';' returns `0'. You might assume that `SELECT COUNT(*) FROM foo WHERE bar NOT LIKE '%baz%';' would return `2'. However, this is not the case: The second query returns `0'. This is because `NULL NOT LIKE EXPR' always returns `NULL', regardless of the value of EXPR. The same is true for aggregate queries involving `NULL' and comparisons using `NOT RLIKE' or `NOT REGEXP'. In such cases, you must test explicitly for `NOT NULL' using `OR' (and not `AND'), as shown here: SELECT COUNT(*) FROM foo WHERE bar NOT LIKE '%baz%' OR bar IS NULL; * `STRCMP(EXPR1,EXPR2)' `STRCMP()' returns `0' if the strings are the same, `-1' if the first argument is smaller than the second according to the current sort order, and `1' otherwise. mysql> SELECT STRCMP('text', 'text2'); -> -1 mysql> SELECT STRCMP('text2', 'text'); -> 1 mysql> SELECT STRCMP('text', 'text'); -> 0 `STRCMP()' performs the comparison using the collation of the arguments. mysql> SET @s1 = _latin1 'x' COLLATE latin1_general_ci; mysql> SET @s2 = _latin1 'X' COLLATE latin1_general_ci; mysql> SET @s3 = _latin1 'x' COLLATE latin1_general_cs; mysql> SET @s4 = _latin1 'X' COLLATE latin1_general_cs; mysql> SELECT STRCMP(@s1, @s2), STRCMP(@s3, @s4); +------------------+------------------+ | STRCMP(@s1, @s2) | STRCMP(@s3, @s4) | +------------------+------------------+ | 0 | 1 | +------------------+------------------+ If the collations are incompatible, one of the arguments must be converted to be compatible with the other. See *Note charset-collation-expressions::. mysql> SELECT STRCMP(@s1, @s3); ERROR 1267 (HY000) at line 10: Illegal mix of collations (latin1_general_ci,IMPLICIT) and (latin1_general_cs,IMPLICIT) for operation 'strcmp' mysql> SELECT STRCMP(@s1, @s3 COLLATE latin1_general_ci); +--------------------------------------------+ | STRCMP(@s1, @s3 COLLATE latin1_general_ci) | +--------------------------------------------+ | 0 | +--------------------------------------------+  File: manual.info, Node: regexp, Prev: string-comparison-functions, Up: string-functions 12.5.2 Regular Expressions -------------------------- *String Regular Expression Operators* Name Description `NOT REGEXP' Negation of REGEXP `REGEXP' Pattern matching using regular expressions `RLIKE' Synonym for REGEXP A regular expression is a powerful way of specifying a pattern for a complex search. MySQL uses Henry Spencer's implementation of regular expressions, which is aimed at conformance with POSIX 1003.2. MySQL uses the extended version to support pattern-matching operations performed with the `REGEXP' operator in SQL statements. This section summarizes, with examples, the special characters and constructs that can be used in MySQL for `REGEXP' operations. It does not contain all the details that can be found in Henry Spencer's `regex(7)' manual page. That manual page is included in MySQL source distributions, in the `regex.7' file under the `regex' directory. See also *Note pattern-matching::. * `EXPR NOT REGEXP PAT', `EXPR NOT RLIKE PAT' This is the same as `NOT (EXPR REGEXP PAT)'. * `EXPR REGEXP PAT', `EXPR RLIKE PAT' Performs a pattern match of a string expression EXPR against a pattern PAT. The pattern can be an extended regular expression. The syntax for regular expressions is discussed in *Note regexp::. Returns `1' if EXPR matches PAT; otherwise it returns `0'. If either EXPR or PAT is `NULL', the result is `NULL'. `RLIKE' is a synonym for `REGEXP', provided for `mSQL' compatibility. The pattern need not be a literal string. For example, it can be specified as a string expression or table column. *Note*: Because MySQL uses the C escape syntax in strings (for example, ``\n'' to represent the newline character), you must double any ``\'' that you use in your `REGEXP' strings. `REGEXP' is not case sensitive, except when used with binary strings. mysql> SELECT 'Monty!' REGEXP '.*'; -> 1 mysql> SELECT 'new*\n*line' REGEXP 'new\\*.\\*line'; -> 1 mysql> SELECT 'a' REGEXP 'A', 'a' REGEXP BINARY 'A'; -> 1 0 mysql> SELECT 'a' REGEXP '^[a-d]'; -> 1 `REGEXP' and `RLIKE' use the current character set when deciding the type of a character. The default is `latin1' (cp1252 West European). *Warning*: The `REGEXP' and `RLIKE' operators work in byte-wise fashion, so they are not multi-byte safe and may produce unexpected results with multi-byte character sets. In addition, these operators compare characters by their byte values and accented characters may not compare as equal even if a given collation treats them as equal. A regular expression describes a set of strings. The simplest regular expression is one that has no special characters in it. For example, the regular expression `hello' matches `hello' and nothing else. Nontrivial regular expressions use certain special constructs so that they can match more than one string. For example, the regular expression `hello|word' matches either the string `hello' or the string `word'. As a more complex example, the regular expression `B[an]*s' matches any of the strings `Bananas', `Baaaaas', `Bs', and any other string starting with a `B', ending with an `s', and containing any number of `a' or `n' characters in between. A regular expression for the `REGEXP' operator may use any of the following special characters and constructs: * `^' Match the beginning of a string. mysql> SELECT 'fo\nfo' REGEXP '^fo$'; -> 0 mysql> SELECT 'fofo' REGEXP '^fo'; -> 1 * `$' Match the end of a string. mysql> SELECT 'fo\no' REGEXP '^fo\no$'; -> 1 mysql> SELECT 'fo\no' REGEXP '^fo$'; -> 0 * `.' Match any character (including carriage return and newline). mysql> SELECT 'fofo' REGEXP '^f.*$'; -> 1 mysql> SELECT 'fo\r\nfo' REGEXP '^f.*$'; -> 1 * `a*' Match any sequence of zero or more `a' characters. mysql> SELECT 'Ban' REGEXP '^Ba*n'; -> 1 mysql> SELECT 'Baaan' REGEXP '^Ba*n'; -> 1 mysql> SELECT 'Bn' REGEXP '^Ba*n'; -> 1 * `a+' Match any sequence of one or more `a' characters. mysql> SELECT 'Ban' REGEXP '^Ba+n'; -> 1 mysql> SELECT 'Bn' REGEXP '^Ba+n'; -> 0 * `a?' Match either zero or one `a' character. mysql> SELECT 'Bn' REGEXP '^Ba?n'; -> 1 mysql> SELECT 'Ban' REGEXP '^Ba?n'; -> 1 mysql> SELECT 'Baan' REGEXP '^Ba?n'; -> 0 * `de|abc' Match either of the sequences `de' or `abc'. mysql> SELECT 'pi' REGEXP 'pi|apa'; -> 1 mysql> SELECT 'axe' REGEXP 'pi|apa'; -> 0 mysql> SELECT 'apa' REGEXP 'pi|apa'; -> 1 mysql> SELECT 'apa' REGEXP '^(pi|apa)$'; -> 1 mysql> SELECT 'pi' REGEXP '^(pi|apa)$'; -> 1 mysql> SELECT 'pix' REGEXP '^(pi|apa)$'; -> 0 * `(abc)*' Match zero or more instances of the sequence `abc'. mysql> SELECT 'pi' REGEXP '^(pi)*$'; -> 1 mysql> SELECT 'pip' REGEXP '^(pi)*$'; -> 0 mysql> SELECT 'pipi' REGEXP '^(pi)*$'; -> 1 * `{1}', `{2,3}' `{n}' or `{m,n}' notation provides a more general way of writing regular expressions that match many occurrences of the previous atom (or `piece') of the pattern. `m' and `n' are integers. * `a*' Can be written as `a{0,}'. * `a+' Can be written as `a{1,}'. * `a?' Can be written as `a{0,1}'. To be more precise, `a{n}' matches exactly `n' instances of `a'. `a{n,}' matches `n' or more instances of `a'. `a{m,n}' matches `m' through `n' instances of `a', inclusive. `m' and `n' must be in the range from `0' to `RE_DUP_MAX' (default 255), inclusive. If both `m' and `n' are given, `m' must be less than or equal to `n'. mysql> SELECT 'abcde' REGEXP 'a[bcd]{2}e'; -> 0 mysql> SELECT 'abcde' REGEXP 'a[bcd]{3}e'; -> 1 mysql> SELECT 'abcde' REGEXP 'a[bcd]{1,10}e'; -> 1 * `[a-dX]', `[^a-dX]' Matches any character that is (or is not, if ^ is used) either `a', `b', `c', `d' or `X'. A `-' character between two other characters forms a range that matches all characters from the first character to the second. For example, `[0-9]' matches any decimal digit. To include a literal `]' character, it must immediately follow the opening bracket `['. To include a literal `-' character, it must be written first or last. Any character that does not have a defined special meaning inside a `[]' pair matches only itself. mysql> SELECT 'aXbc' REGEXP '[a-dXYZ]'; -> 1 mysql> SELECT 'aXbc' REGEXP '^[a-dXYZ]$'; -> 0 mysql> SELECT 'aXbc' REGEXP '^[a-dXYZ]+$'; -> 1 mysql> SELECT 'aXbc' REGEXP '^[^a-dXYZ]+$'; -> 0 mysql> SELECT 'gheis' REGEXP '^[^a-dXYZ]+$'; -> 1 mysql> SELECT 'gheisa' REGEXP '^[^a-dXYZ]+$'; -> 0 * `[.characters.]' Within a bracket expression (written using `[' and `]'), matches the sequence of characters of that collating element. `characters' is either a single character or a character name like `newline'. The following table lists the permissible character names. The following table shows the permissible character names and the characters that they match. For characters given as numeric values, the values are represented in octal. Name Character Name Character `NUL' `0' `SOH' `001' `STX' `002' `ETX' `003' `EOT' `004' `ENQ' `005' `ACK' `006' `BEL' `007' `alert' `007' `BS' `010' `backspace' `'\b'' `HT' `011' `tab' `'\t'' `LF' `012' `newline' `'\n'' `VT' `013' `vertical-tab' `'\v'' `FF' `014' `form-feed' `'\f'' `CR' `015' `carriage-return' `'\r'' `SO' `016' `SI' `017' `DLE' `020' `DC1' `021' `DC2' `022' `DC3' `023' `DC4' `024' `NAK' `025' `SYN' `026' `ETB' `027' `CAN' `030' `EM' `031' `SUB' `032' `ESC' `033' `IS4' `034' `FS' `034' `IS3' `035' `GS' `035' `IS2' `036' `RS' `036' `IS1' `037' `US' `037' `space' `' '' `exclamation-mark'`'!'' `quotation-mark' `'"'' `number-sign' `'#'' `dollar-sign' `'$'' `percent-sign' `'%'' `ampersand' `'&'' `apostrophe' `'\''' `left-parenthesis'`'('' `right-parenthesis'`')'' `asterisk' `'*'' `plus-sign' `'+'' `comma' `','' `hyphen' `'-'' `hyphen-minus' `'-'' `period' `'.'' `full-stop' `'.'' `slash' `'/'' `solidus' `'/'' `zero' `'0'' `one' `'1'' `two' `'2'' `three' `'3'' `four' `'4'' `five' `'5'' `six' `'6'' `seven' `'7'' `eight' `'8'' `nine' `'9'' `colon' `':'' `semicolon' `';'' `less-than-sign' `'<'' `equals-sign' `'='' `greater-than-sign'`'>'' `question-mark' `'?'' `commercial-at' `'@'' `left-square-bracket'`'['' `backslash' `'\\'' `reverse-solidus' `'\\'' `right-square-bracket'`']'' `circumflex' `'^'' `circumflex-accent'`'^'' `underscore' `'_'' `low-line' `'_'' `grave-accent' `'`'' `left-brace' `'{'' `left-curly-bracket'`'{'' `vertical-line' `'|'' `right-brace' `'}'' `right-curly-bracket'`'}'' `tilde' `'~'' `DEL' `177' mysql> SELECT '~' REGEXP '[[.~.]]'; -> 1 mysql> SELECT '~' REGEXP '[[.tilde.]]'; -> 1 * `[=character_class=]' Within a bracket expression (written using `[' and `]'), `[=character_class=]' represents an equivalence class. It matches all characters with the same collation value, including itself. For example, if `o' and `(+)' are the members of an equivalence class, `[[=o=]]', `[[=(+)=]]', and `[o(+)]' are all synonymous. An equivalence class may not be used as an endpoint of a range. * `[:character_class:]' Within a bracket expression (written using `[' and `]'), `[:character_class:]' represents a character class that matches all characters belonging to that class. The following table lists the standard class names. These names stand for the character classes defined in the `ctype(3)' manual page. A particular locale may provide other class names. A character class may not be used as an endpoint of a range. Character Meaning Class Name `alnum' Alphanumeric characters `alpha' Alphabetic characters `blank' Whitespace characters `cntrl' Control characters `digit' Digit characters `graph' Graphic characters `lower' Lowercase alphabetic characters `print' Graphic or space characters `punct' Punctuation characters `space' Space, tab, newline, and carriage return `upper' Uppercase alphabetic characters `xdigit' Hexadecimal digit characters mysql> SELECT 'justalnums' REGEXP '[[:alnum:]]+'; -> 1 mysql> SELECT '!!' REGEXP '[[:alnum:]]+'; -> 0 * `[[:<:]]', `[[:>:]]' These markers stand for word boundaries. They match the beginning and end of words, respectively. A word is a sequence of word characters that is not preceded by or followed by word characters. A word character is an alphanumeric character in the `alnum' class or an underscore (`_'). mysql> SELECT 'a word a' REGEXP '[[:<:]]word[[:>:]]'; -> 1 mysql> SELECT 'a xword a' REGEXP '[[:<:]]word[[:>:]]'; -> 0 To use a literal instance of a special character in a regular expression, precede it by two backslash (\) characters. The MySQL parser interprets one of the backslashes, and the regular expression library interprets the other. For example, to match the string `1+2' that contains the special `+' character, only the last of the following regular expressions is the correct one: mysql> SELECT '1+2' REGEXP '1+2'; -> 0 mysql> SELECT '1+2' REGEXP '1\+2'; -> 0 mysql> SELECT '1+2' REGEXP '1\\+2'; -> 1  File: manual.info, Node: numeric-functions, Next: date-and-time-functions, Prev: string-functions, Up: functions 12.6 Numeric Functions and Operators ==================================== * Menu: * arithmetic-functions:: Arithmetic Operators * mathematical-functions:: Mathematical Functions *Numeric Functions and Operators* Name Description `ABS()' Return the absolute value `ACOS()' Return the arc cosine `ASIN()' Return the arc sine `ATAN2()', `ATAN()' Return the arc tangent of the two arguments `ATAN()' Return the arc tangent `CEIL()' Return the smallest integer value not less than the argument `CEILING()' Return the smallest integer value not less than the argument `CONV()' Convert numbers between different number bases `COS()' Return the cosine `COT()' Return the cotangent `CRC32()' Compute a cyclic redundancy check value `DEGREES()' Convert radians to degrees `DIV' Integer division `/' Division operator `EXP()' Raise to the power of `FLOOR()' Return the largest integer value not greater than the argument `LN()' Return the natural logarithm of the argument `LOG10()' Return the base-10 logarithm of the argument `LOG2()' Return the base-2 logarithm of the argument `LOG()' Return the natural logarithm of the first argument `-' Minus operator `MOD()' Return the remainder `%' Modulo operator `OCT()' Return an octal representation of a decimal number `PI()' Return the value of pi `+' Addition operator `POW()' Return the argument raised to the specified power `POWER()' Return the argument raised to the specified power `RADIANS()' Return argument converted to radians `RAND()' Return a random floating-point value `ROUND()' Round the argument `SIGN()' Return the sign of the argument `SIN()' Return the sine of the argument `SQRT()' Return the square root of the argument `TAN()' Return the tangent of the argument `*' Multiplication operator `TRUNCATE()' Truncate to specified number of decimal places `-' Change the sign of the argument  File: manual.info, Node: arithmetic-functions, Next: mathematical-functions, Prev: numeric-functions, Up: numeric-functions 12.6.1 Arithmetic Operators --------------------------- *Arithmetic Operators* Name Description `DIV' Integer division `/' Division operator `-' Minus operator `%' Modulo operator `+' Addition operator `*' Multiplication operator `-' Change the sign of the argument The usual arithmetic operators are available. The result is determined according to the following rules: * In the case of `-', `+', and `*', the result is calculated with *Note `BIGINT': numeric-types. (64-bit) precision if both operands are integers. * If both operands are integers and any of them are unsigned, the result is an unsigned integer. For subtraction, if the `NO_UNSIGNED_SUBTRACTION' SQL mode is enabled, the result is signed even if any operand is unsigned. * If any of the operands of a `+', `-', `/', `*', `%' is a real or string value, the precision of the result is the precision of the operand with the maximum precision. * In division performed with `/', the scale of the result when using two exact-value operands is the scale of the first operand plus the value of the `div_precision_increment' system variable (which is 4 by default). For example, the result of the expression `5.05 / 0.014' has a scale of six decimal places (`360.714286'). These rules are applied for each operation, such that nested calculations imply the precision of each component. Hence, `(14620 / 9432456) / (24250 / 9432456)', resolves first to `(0.0014) / (0.0026)', with the final result having 8 decimal places (`0.60288653'). Because of these rules and the way they are applied, care should be taken to ensure that components and subcomponents of a calculation use the appropriate level of precision. See *Note cast-functions::. For information about handling of overflow in numeric expression evaluation, see *Note out-of-range-and-overflow::. Arithmetic operators apply to numbers. For other types of values, alternative operations may be available. For example, to add date values, use `DATE_ADD()'; see *Note date-and-time-functions::. * `+' Addition: mysql> SELECT 3+5; -> 8 * `-' Subtraction: mysql> SELECT 3-5; -> -2 * `-' Unary minus. This operator changes the sign of the operand. mysql> SELECT - 2; -> -2 *Note*: If this operator is used with a *Note `BIGINT': numeric-types, the return value is also a *Note `BIGINT': numeric-types. This means that you should avoid using `-' on integers that may have the value of -2^63. * `*' Multiplication: mysql> SELECT 3*5; -> 15 mysql> SELECT 18014398509481984*18014398509481984.0; -> 324518553658426726783156020576256.0 * `/' Division: mysql> SELECT 3/5; -> 0.60 Division by zero produces a `NULL' result: mysql> SELECT 102/(1-1); -> NULL A division is calculated with *Note `BIGINT': numeric-types. arithmetic only if performed in a context where its result is converted to an integer. * `DIV' Integer division. Similar to `FLOOR()', but is safe with *Note `BIGINT': numeric-types. values. Incorrect results may occur for noninteger operands that exceed *Note `BIGINT': numeric-types. range. mysql> SELECT 5 DIV 2; -> 2 * `N % M' Modulo operation. Returns the remainder of N divided by M. For more information, see the description for the `MOD()' function in *Note mathematical-functions::.  File: manual.info, Node: mathematical-functions, Prev: arithmetic-functions, Up: numeric-functions 12.6.2 Mathematical Functions ----------------------------- *Mathematical Functions* Name Description `ABS()' Return the absolute value `ACOS()' Return the arc cosine `ASIN()' Return the arc sine `ATAN2()', `ATAN()' Return the arc tangent of the two arguments `ATAN()' Return the arc tangent `CEIL()' Return the smallest integer value not less than the argument `CEILING()' Return the smallest integer value not less than the argument `CONV()' Convert numbers between different number bases `COS()' Return the cosine `COT()' Return the cotangent `CRC32()' Compute a cyclic redundancy check value `DEGREES()' Convert radians to degrees `EXP()' Raise to the power of `FLOOR()' Return the largest integer value not greater than the argument `LN()' Return the natural logarithm of the argument `LOG10()' Return the base-10 logarithm of the argument `LOG2()' Return the base-2 logarithm of the argument `LOG()' Return the natural logarithm of the first argument `MOD()' Return the remainder `OCT()' Return an octal representation of a decimal number `PI()' Return the value of pi `POW()' Return the argument raised to the specified power `POWER()' Return the argument raised to the specified power `RADIANS()' Return argument converted to radians `RAND()' Return a random floating-point value `ROUND()' Round the argument `SIGN()' Return the sign of the argument `SIN()' Return the sine of the argument `SQRT()' Return the square root of the argument `TAN()' Return the tangent of the argument `TRUNCATE()' Truncate to specified number of decimal places All mathematical functions return `NULL' in the event of an error. * `ABS(X)' Returns the absolute value of X. mysql> SELECT ABS(2); -> 2 mysql> SELECT ABS(-32); -> 32 This function is safe to use with *Note `BIGINT': numeric-types. values. * `ACOS(X)' Returns the arc cosine of X, that is, the value whose cosine is X. Returns `NULL' if X is not in the range `-1' to `1'. mysql> SELECT ACOS(1); -> 0 mysql> SELECT ACOS(1.0001); -> NULL mysql> SELECT ACOS(0); -> 1.5707963267949 * `ASIN(X)' Returns the arc sine of X, that is, the value whose sine is X. Returns `NULL' if X is not in the range `-1' to `1'. mysql> SELECT ASIN(0.2); -> 0.20135792079033 mysql> SELECT ASIN('foo'); +-------------+ | ASIN('foo') | +-------------+ | 0 | +-------------+ 1 row in set, 1 warning (0.00 sec) mysql> SHOW WARNINGS; +---------+------+-----------------------------------------+ | Level | Code | Message | +---------+------+-----------------------------------------+ | Warning | 1292 | Truncated incorrect DOUBLE value: 'foo' | +---------+------+-----------------------------------------+ * `ATAN(X)' Returns the arc tangent of X, that is, the value whose tangent is X. mysql> SELECT ATAN(2); -> 1.1071487177941 mysql> SELECT ATAN(-2); -> -1.1071487177941 * `ATAN(Y,X)', `ATAN2(Y,X)' Returns the arc tangent of the two variables X and Y. It is similar to calculating the arc tangent of `Y / X', except that the signs of both arguments are used to determine the quadrant of the result. mysql> SELECT ATAN(-2,2); -> -0.78539816339745 mysql> SELECT ATAN2(PI(),0); -> 1.5707963267949 * `CEIL(X)' `CEIL()' is a synonym for `CEILING()'. * `CEILING(X)' Returns the smallest integer value not less than X. mysql> SELECT CEILING(1.23); -> 2 mysql> SELECT CEILING(-1.23); -> -1 For exact-value numeric arguments, the return value has an exact-value numeric type. For string or floating-point arguments, the return value has a floating-point type. * `CONV(N,FROM_BASE,TO_BASE)' Converts numbers between different number bases. Returns a string representation of the number N, converted from base FROM_BASE to base TO_BASE. Returns `NULL' if any argument is `NULL'. The argument N is interpreted as an integer, but may be specified as an integer or a string. The minimum base is `2' and the maximum base is `36'. If TO_BASE is a negative number, N is regarded as a signed number. Otherwise, N is treated as unsigned. `CONV()' works with 64-bit precision. mysql> SELECT CONV('a',16,2); -> '1010' mysql> SELECT CONV('6E',18,8); -> '172' mysql> SELECT CONV(-17,10,-18); -> '-H' mysql> SELECT CONV(10+'10'+'10'+0xa,10,10); -> '40' * `COS(X)' Returns the cosine of X, where X is given in radians. mysql> SELECT COS(PI()); -> -1 * `COT(X)' Returns the cotangent of X. mysql> SELECT COT(12); -> -1.5726734063977 mysql> SELECT COT(0); -> NULL * `CRC32(EXPR)' Computes a cyclic redundancy check value and returns a 32-bit unsigned value. The result is `NULL' if the argument is `NULL'. The argument is expected to be a string and (if possible) is treated as one if it is not. mysql> SELECT CRC32('MySQL'); -> 3259397556 mysql> SELECT CRC32('mysql'); -> 2501908538 * `DEGREES(X)' Returns the argument X, converted from radians to degrees. mysql> SELECT DEGREES(PI()); -> 180 mysql> SELECT DEGREES(PI() / 2); -> 90 * `EXP(X)' Returns the value of _e_ (the base of natural logarithms) raised to the power of X. The inverse of this function is `LOG()' (using a single argument only) or `LN()'. mysql> SELECT EXP(2); -> 7.3890560989307 mysql> SELECT EXP(-2); -> 0.13533528323661 mysql> SELECT EXP(0); -> 1 * `FLOOR(X)' Returns the largest integer value not greater than X. mysql> SELECT FLOOR(1.23); -> 1 mysql> SELECT FLOOR(-1.23); -> -2 For exact-value numeric arguments, the return value has an exact-value numeric type. For string or floating-point arguments, the return value has a floating-point type. * `FORMAT(X,D)' Formats the number X to a format like `'#,###,###.##'', rounded to D decimal places, and returns the result as a string. For details, see *Note string-functions::. * `HEX(N_or_S)' This function can be used to obtain a hexadecimal representation of a decimal number or a string; the manner in which it does so varies according to the argument's type. See this function's description in *Note string-functions::, for details. * `LN(X)' Returns the natural logarithm of X; that is, the base-_e_ logarithm of X. If X is less than or equal to 0, then `NULL' is returned. mysql> SELECT LN(2); -> 0.69314718055995 mysql> SELECT LN(-2); -> NULL This function is synonymous with `LOG(X)'. The inverse of this function is the `EXP()' function. * `LOG(X)', `LOG(B,X)' If called with one parameter, this function returns the natural logarithm of X. If X is less than or equal to 0, then `NULL' is returned. The inverse of this function (when called with a single argument) is the `EXP()' function. mysql> SELECT LOG(2); -> 0.69314718055995 mysql> SELECT LOG(-2); -> NULL If called with two parameters, this function returns the logarithm of X to the base B. If X is less than or equal to 0, or if B is less than or equal to 1, then `NULL' is returned. mysql> SELECT LOG(2,65536); -> 16 mysql> SELECT LOG(10,100); -> 2 mysql> SELECT LOG(1,100); -> NULL `LOG(B,X)' is equivalent to `LOG(X) / LOG(B)'. * `LOG2(X)' Returns the base-2 logarithm of `X'. mysql> SELECT LOG2(65536); -> 16 mysql> SELECT LOG2(-100); -> NULL `LOG2()' is useful for finding out how many bits a number requires for storage. This function is equivalent to the expression `LOG(X) / LOG(2)'. * `LOG10(X)' Returns the base-10 logarithm of X. mysql> SELECT LOG10(2); -> 0.30102999566398 mysql> SELECT LOG10(100); -> 2 mysql> SELECT LOG10(-100); -> NULL `LOG10(X)' is equivalent to `LOG(10,X)'. * `MOD(N,M)', `N % M', `N MOD M' Modulo operation. Returns the remainder of N divided by M. mysql> SELECT MOD(234, 10); -> 4 mysql> SELECT 253 % 7; -> 1 mysql> SELECT MOD(29,9); -> 2 mysql> SELECT 29 MOD 9; -> 2 This function is safe to use with *Note `BIGINT': numeric-types. values. `MOD()' also works on values that have a fractional part and returns the exact remainder after division: mysql> SELECT MOD(34.5,3); -> 1.5 `MOD(N,0)' returns `NULL'. * `OCT(N)' Returns a string representation of the octal value of N, where N is a longlong (*Note `BIGINT': numeric-types.) number. This is equivalent to `CONV(N,10,8)'. Returns `NULL' if N is `NULL'. mysql> SELECT OCT(12); -> '14' * `PI()' Returns the value of π (pi). The default number of decimal places displayed is seven, but MySQL uses the full double-precision value internally. mysql> SELECT PI(); -> 3.141593 mysql> SELECT PI()+0.000000000000000000; -> 3.141592653589793116 * `POW(X,Y)' Returns the value of X raised to the power of Y. mysql> SELECT POW(2,2); -> 4 mysql> SELECT POW(2,-2); -> 0.25 * `POWER(X,Y)' This is a synonym for `POW()'. * `RADIANS(X)' Returns the argument X, converted from degrees to radians. (Note that π radians equals 180 degrees.) mysql> SELECT RADIANS(90); -> 1.5707963267949 * `RAND()', `RAND(N)' Returns a random floating-point value V in the range `0' <= V < `1.0'. If a constant integer argument N is specified, it is used as the seed value, which produces a repeatable sequence of column values. In the following example, note that the sequences of values produced by `RAND(3)' is the same both places where it occurs. mysql> CREATE TABLE t (i INT); Query OK, 0 rows affected (0.42 sec) mysql> INSERT INTO t VALUES(1),(2),(3); Query OK, 3 rows affected (0.00 sec) Records: 3 Duplicates: 0 Warnings: 0 mysql> SELECT i, RAND() FROM t; +------+------------------+ | i | RAND() | +------+------------------+ | 1 | 0.61914388706828 | | 2 | 0.93845168309142 | | 3 | 0.83482678498591 | +------+------------------+ 3 rows in set (0.00 sec) mysql> SELECT i, RAND(3) FROM t; +------+------------------+ | i | RAND(3) | +------+------------------+ | 1 | 0.90576975597606 | | 2 | 0.37307905813035 | | 3 | 0.14808605345719 | +------+------------------+ 3 rows in set (0.00 sec) mysql> SELECT i, RAND() FROM t; +------+------------------+ | i | RAND() | +------+------------------+ | 1 | 0.35877890638893 | | 2 | 0.28941420772058 | | 3 | 0.37073435016976 | +------+------------------+ 3 rows in set (0.00 sec) mysql> SELECT i, RAND(3) FROM t; +------+------------------+ | i | RAND(3) | +------+------------------+ | 1 | 0.90576975597606 | | 2 | 0.37307905813035 | | 3 | 0.14808605345719 | +------+------------------+ 3 rows in set (0.01 sec) With a constant initializer, the seed is initialized once when the statement is compiled, prior to execution. As of MySQL 5.1.16, if a nonconstant initializer (such as a column name) is used as the argument, the seed is initialized with the value for each invocation of `RAND()'. (One implication of this is that for equal argument values, `RAND()' will return the same value each time.) From MySQL 5.1.3 to 5.1.15, nonconstant arguments are not permitted. Before that, the effect of using a nonconstant argument is undefined. To obtain a random integer R in the range I <= R < J, use the expression `FLOOR(I + RAND() * (J' - `I))'. For example, to obtain a random integer in the range the range `7' <= R < `12', you could use the following statement: SELECT FLOOR(7 + (RAND() * 5)); `RAND()' in a `WHERE' clause is re-evaluated every time the `WHERE' is executed. You cannot use a column with `RAND()' values in an `ORDER BY' clause, because `ORDER BY' would evaluate the column multiple times. However, you can retrieve rows in random order like this: mysql> SELECT * FROM TBL_NAME ORDER BY RAND(); `ORDER BY RAND()' combined with `LIMIT' is useful for selecting a random sample from a set of rows: mysql> SELECT * FROM table1, table2 WHERE a=b AND c ORDER BY RAND() LIMIT 1000; `RAND()' is not meant to be a perfect random generator. It is a fast way to generate random numbers on demand that is portable between platforms for the same MySQL version. Beginning with MySQL 5.1.43, this function is flagged as unsafe for statement-based replication; use of this function causes a warning when using statement-based replication, and the statement is logged using the binary format when `binlog_format' is `MIXED'. (Bug#49222) * `ROUND(X)', `ROUND(X,D)' Rounds the argument X to D decimal places. The rounding algorithm depends on the data type of X. D defaults to 0 if not specified. D can be negative to cause D digits left of the decimal point of the value X to become zero. mysql> SELECT ROUND(-1.23); -> -1 mysql> SELECT ROUND(-1.58); -> -2 mysql> SELECT ROUND(1.58); -> 2 mysql> SELECT ROUND(1.298, 1); -> 1.3 mysql> SELECT ROUND(1.298, 0); -> 1 mysql> SELECT ROUND(23.298, -1); -> 20 The return type is the same type as that of the first argument (assuming that it is integer, double, or decimal). This means that for an integer argument, the result is an integer (no decimal places): mysql> SELECT ROUND(150.000,2), ROUND(150,2); +------------------+--------------+ | ROUND(150.000,2) | ROUND(150,2) | +------------------+--------------+ | 150.00 | 150 | +------------------+--------------+ `ROUND()' uses the following rules depending on the type of the first argument: * For exact-value numbers, `ROUND()' uses the `round half up' or `round toward nearest' rule: A value with a fractional part of .5 or greater is rounded up to the next integer if positive or down to the next integer if negative. (In other words, it is rounded away from zero.) A value with a fractional part less than .5 is rounded down to the next integer if positive or up to the next integer if negative. * For approximate-value numbers, the result depends on the C library. On many systems, this means that `ROUND()' uses the "round to nearest even" rule: A value with any fractional part is rounded to the nearest even integer. The following example shows how rounding differs for exact and approximate values: mysql> SELECT ROUND(2.5), ROUND(25E-1); +------------+--------------+ | ROUND(2.5) | ROUND(25E-1) | +------------+--------------+ | 3 | 2 | +------------+--------------+ For more information, see *Note precision-math::. * `SIGN(X)' Returns the sign of the argument as `-1', `0', or `1', depending on whether X is negative, zero, or positive. mysql> SELECT SIGN(-32); -> -1 mysql> SELECT SIGN(0); -> 0 mysql> SELECT SIGN(234); -> 1 * `SIN(X)' Returns the sine of X, where X is given in radians. mysql> SELECT SIN(PI()); -> 1.2246063538224e-16 mysql> SELECT ROUND(SIN(PI())); -> 0 * `SQRT(X)' Returns the square root of a nonnegative number X. mysql> SELECT SQRT(4); -> 2 mysql> SELECT SQRT(20); -> 4.4721359549996 mysql> SELECT SQRT(-16); -> NULL * `TAN(X)' Returns the tangent of X, where X is given in radians. mysql> SELECT TAN(PI()); -> -1.2246063538224e-16 mysql> SELECT TAN(PI()+1); -> 1.5574077246549 * `TRUNCATE(X,D)' Returns the number X, truncated to D decimal places. If D is `0', the result has no decimal point or fractional part. D can be negative to cause D digits left of the decimal point of the value X to become zero. mysql> SELECT TRUNCATE(1.223,1); -> 1.2 mysql> SELECT TRUNCATE(1.999,1); -> 1.9 mysql> SELECT TRUNCATE(1.999,0); -> 1 mysql> SELECT TRUNCATE(-1.999,1); -> -1.9 mysql> SELECT TRUNCATE(122,-2); -> 100 mysql> SELECT TRUNCATE(10.28*100,0); -> 1028 All numbers are rounded toward zero.  File: manual.info, Node: date-and-time-functions, Next: mysql-calendar, Prev: numeric-functions, Up: functions 12.7 Date and Time Functions ============================ This section describes the functions that can be used to manipulate temporal values. See *Note date-and-time-types::, for a description of the range of values each date and time type has and the valid formats in which values may be specified. *Date/Time Functions* Name Description `ADDDATE()' Add time values (intervals) to a date value `ADDTIME()' Add time `CONVERT_TZ()' Convert from one timezone to another `CURDATE()' Return the current date `CURRENT_DATE()', Synonyms for CURDATE() `CURRENT_DATE' `CURRENT_TIME()', Synonyms for CURTIME() `CURRENT_TIME' `CURRENT_TIMESTAMP()', Synonyms for NOW() `CURRENT_TIMESTAMP' `CURTIME()' Return the current time `DATE_ADD()' Add time values (intervals) to a date value `DATE_FORMAT()' Format date as specified `DATE_SUB()' Subtract a time value (interval) from a date `DATE()' Extract the date part of a date or datetime expression `DATEDIFF()' Subtract two dates `DAY()' Synonym for DAYOFMONTH() `DAYNAME()' Return the name of the weekday `DAYOFMONTH()' Return the day of the month (0-31) `DAYOFWEEK()' Return the weekday index of the argument `DAYOFYEAR()' Return the day of the year (1-366) `EXTRACT()' Extract part of a date `FROM_DAYS()' Convert a day number to a date `FROM_UNIXTIME()' Format UNIX timestamp as a date `GET_FORMAT()' Return a date format string `HOUR()' Extract the hour `LAST_DAY' Return the last day of the month for the argument `LOCALTIME()', `LOCALTIME' Synonym for NOW() `LOCALTIMESTAMP', Synonym for NOW() `LOCALTIMESTAMP()' `MAKEDATE()' Create a date from the year and day of year `MAKETIME' MAKETIME() `MICROSECOND()' Return the microseconds from argument `MINUTE()' Return the minute from the argument `MONTH()' Return the month from the date passed `MONTHNAME()' Return the name of the month `NOW()' Return the current date and time `PERIOD_ADD()' Add a period to a year-month `PERIOD_DIFF()' Return the number of months between periods `QUARTER()' Return the quarter from a date argument `SEC_TO_TIME()' Converts seconds to 'HH:MM:SS' format `SECOND()' Return the second (0-59) `STR_TO_DATE()' Convert a string to a date `SUBDATE()' A synonym for DATE_SUB() when invoked with three arguments `SUBTIME()' Subtract times `SYSDATE()' Return the time at which the function executes `TIME_FORMAT()' Format as time `TIME_TO_SEC()' Return the argument converted to seconds `TIME()' Extract the time portion of the expression passed `TIMEDIFF()' Subtract time `TIMESTAMP()' With a single argument, this function returns the date or datetime expression; with two arguments, the sum of the arguments `TIMESTAMPADD()' Add an interval to a datetime expression `TIMESTAMPDIFF()' Subtract an interval from a datetime expression `TO_DAYS()' Return the date argument converted to days `UNIX_TIMESTAMP()' Return a UNIX timestamp `UTC_DATE()' Return the current UTC date `UTC_TIME()' Return the current UTC time `UTC_TIMESTAMP()' Return the current UTC date and time `WEEK()' Return the week number `WEEKDAY()' Return the weekday index `WEEKOFYEAR()' Return the calendar week of the date (0-53) `YEAR()' Return the year `YEARWEEK()' Return the year and week Here is an example that uses date functions. The following query selects all rows with a DATE_COL value from within the last 30 days: mysql> SELECT SOMETHING FROM TBL_NAME -> WHERE DATE_SUB(CURDATE(),INTERVAL 30 DAY) <= DATE_COL; The query also selects rows with dates that lie in the future. Functions that expect date values usually accept datetime values and ignore the time part. Functions that expect time values usually accept datetime values and ignore the date part. Functions that return the current date or time each are evaluated only once per query at the start of query execution. This means that multiple references to a function such as `NOW()' within a single query always produce the same result. (For our purposes, a single query also includes a call to a stored program (stored routine, trigger, or event) and all subprograms called by that program.) This principle also applies to `CURDATE()', `CURTIME()', `UTC_DATE()', `UTC_TIME()', `UTC_TIMESTAMP()', and to any of their synonyms. The `CURRENT_TIMESTAMP()', `CURRENT_TIME()', `CURRENT_DATE()', and `FROM_UNIXTIME()' functions return values in the connection's current time zone, which is available as the value of the `time_zone' system variable. In addition, `UNIX_TIMESTAMP()' assumes that its argument is a datetime value in the current time zone. See *Note time-zone-support::. Some date functions can be used with `zero' dates or incomplete dates such as `'2001-11-00'', whereas others cannot. Functions that extract parts of dates typically work with incomplete dates and thus can return 0 when you might otherwise expect a nonzero value. For example: mysql> SELECT DAYOFMONTH('2001-11-00'), MONTH('2005-00-00'); -> 0, 0 Other functions expect complete dates and return `NULL' for incomplete dates. These include functions that perform date arithmetic or that map parts of dates to names. For example: mysql> SELECT DATE_ADD('2006-05-00',INTERVAL 1 DAY); -> NULL mysql> SELECT DAYNAME('2006-05-00'); -> NULL * `ADDDATE(DATE,INTERVAL EXPR UNIT)', `ADDDATE(EXPR,DAYS)' When invoked with the `INTERVAL' form of the second argument, `ADDDATE()' is a synonym for `DATE_ADD()'. The related function `SUBDATE()' is a synonym for `DATE_SUB()'. For information on the `INTERVAL' UNIT argument, see the discussion for `DATE_ADD()'. mysql> SELECT DATE_ADD('2008-01-02', INTERVAL 31 DAY); -> '2008-02-02' mysql> SELECT ADDDATE('2008-01-02', INTERVAL 31 DAY); -> '2008-02-02' When invoked with the DAYS form of the second argument, MySQL treats it as an integer number of days to be added to EXPR. mysql> SELECT ADDDATE('2008-01-02', 31); -> '2008-02-02' * `ADDTIME(EXPR1,EXPR2)' `ADDTIME()' adds EXPR2 to EXPR1 and returns the result. EXPR1 is a time or datetime expression, and EXPR2 is a time expression. mysql> SELECT ADDTIME('2007-12-31 23:59:59.999999', '1 1:1:1.000002'); -> '2008-01-02 01:01:01.000001' mysql> SELECT ADDTIME('01:00:00.999999', '02:00:00.999998'); -> '03:00:01.999997' * `CONVERT_TZ(DT,FROM_TZ,TO_TZ)' `CONVERT_TZ()' converts a datetime value DT from the time zone given by FROM_TZ to the time zone given by TO_TZ and returns the resulting value. Time zones are specified as described in *Note time-zone-support::. This function returns `NULL' if the arguments are invalid. If the value falls out of the supported range of the *Note `TIMESTAMP': datetime. type when converted from FROM_TZ to UTC, no conversion occurs. The *Note `TIMESTAMP': datetime. range is described in *Note date-and-time-type-overview::. mysql> SELECT CONVERT_TZ('2004-01-01 12:00:00','GMT','MET'); -> '2004-01-01 13:00:00' mysql> SELECT CONVERT_TZ('2004-01-01 12:00:00','+00:00','+10:00'); -> '2004-01-01 22:00:00' *Note*: To use named time zones such as `'MET'' or `'Europe/Moscow'', the time zone tables must be properly set up. See *Note time-zone-support::, for instructions. Before MySQL 5.1.17, if you intend to use `CONVERT_TZ()' while other tables are locked with *Note `LOCK TABLES': lock-tables, you must also lock the `mysql.time_zone_name' table. See *Note lock-tables::. * `CURDATE()' Returns the current date as a value in `'YYYY-MM-DD'' or `YYYYMMDD' format, depending on whether the function is used in a string or numeric context. mysql> SELECT CURDATE(); -> '2008-06-13' mysql> SELECT CURDATE() + 0; -> 20080613 * `CURRENT_DATE', `CURRENT_DATE()' `CURRENT_DATE' and `CURRENT_DATE()' are synonyms for `CURDATE()'. * `CURTIME()' Returns the current time as a value in `'HH:MM:SS'' or `HHMMSS.uuuuuu' format, depending on whether the function is used in a string or numeric context. The value is expressed in the current time zone. mysql> SELECT CURTIME(); -> '23:50:26' mysql> SELECT CURTIME() + 0; -> 235026.000000 * `CURRENT_TIME', `CURRENT_TIME()' `CURRENT_TIME' and `CURRENT_TIME()' are synonyms for `CURTIME()'. * `CURRENT_TIMESTAMP', `CURRENT_TIMESTAMP()' `CURRENT_TIMESTAMP' and `CURRENT_TIMESTAMP()' are synonyms for `NOW()'. * `DATE(EXPR)' Extracts the date part of the date or datetime expression EXPR. mysql> SELECT DATE('2003-12-31 01:02:03'); -> '2003-12-31' * `DATEDIFF(EXPR1,EXPR2)' `DATEDIFF()' returns EXPR1 - EXPR2 expressed as a value in days from one date to the other. EXPR1 and EXPR2 are date or date-and-time expressions. Only the date parts of the values are used in the calculation. mysql> SELECT DATEDIFF('2007-12-31 23:59:59','2007-12-30'); -> 1 mysql> SELECT DATEDIFF('2010-11-30 23:59:59','2010-12-31'); -> -31 * `DATE_ADD(DATE,INTERVAL EXPR UNIT)', `DATE_SUB(DATE,INTERVAL EXPR UNIT)' These functions perform date arithmetic. The DATE argument specifies the starting date or datetime value. EXPR is an expression specifying the interval value to be added or subtracted from the starting date. EXPR is a string; it may start with a ``-'' for negative intervals. UNIT is a keyword indicating the units in which the expression should be interpreted. The `INTERVAL' keyword and the UNIT specifier are not case sensitive. The following table shows the expected form of the EXPR argument for each UNIT value. UNIT Value Expected EXPR Format `MICROSECOND' `MICROSECONDS' `SECOND' `SECONDS' `MINUTE' `MINUTES' `HOUR' `HOURS' `DAY' `DAYS' `WEEK' `WEEKS' `MONTH' `MONTHS' `QUARTER' `QUARTERS' `YEAR' `YEARS' `SECOND_MICROSECOND' `'SECONDS.MICROSECONDS'' `MINUTE_MICROSECOND' `'MINUTES:SECONDS.MICROSECONDS'' `MINUTE_SECOND' `'MINUTES:SECONDS'' `HOUR_MICROSECOND' `'HOURS:MINUTES:SECONDS.MICROSECONDS'' `HOUR_SECOND' `'HOURS:MINUTES:SECONDS'' `HOUR_MINUTE' `'HOURS:MINUTES'' `DAY_MICROSECOND' `'DAYS HOURS:MINUTES:SECONDS.MICROSECONDS'' `DAY_SECOND' `'DAYS HOURS:MINUTES:SECONDS'' `DAY_MINUTE' `'DAYS HOURS:MINUTES'' `DAY_HOUR' `'DAYS HOURS'' `YEAR_MONTH' `'YEARS-MONTHS'' The return value depends on the arguments: * *Note `DATETIME': datetime. if the first argument is a *Note `DATETIME': datetime. (or *Note `TIMESTAMP': datetime.) value, or if the first argument is a *Note `DATE': datetime. and the UNIT value uses `HOURS', `MINUTES', or `SECONDS'. * String otherwise. To ensure that the result is *Note `DATETIME': datetime, you can use `CAST()' to convert the first argument to *Note `DATETIME': datetime. MySQL permits any punctuation delimiter in the EXPR format. Those shown in the table are the suggested delimiters. If the DATE argument is a *Note `DATE': datetime. value and your calculations involve only `YEAR', `MONTH', and `DAY' parts (that is, no time parts), the result is a *Note `DATE': datetime. value. Otherwise, the result is a *Note `DATETIME': datetime. value. Date arithmetic also can be performed using `INTERVAL' together with the `+' or `-' operator: `date' + INTERVAL EXPR UNIT `date' - INTERVAL EXPR UNIT `INTERVAL EXPR UNIT' is permitted on either side of the `+' operator if the expression on the other side is a date or datetime value. For the `-' operator, `INTERVAL EXPR UNIT' is permitted only on the right side, because it makes no sense to subtract a date or datetime value from an interval. mysql> SELECT '2008-12-31 23:59:59' + INTERVAL 1 SECOND; -> '2009-01-01 00:00:00' mysql> SELECT INTERVAL 1 DAY + '2008-12-31'; -> '2009-01-01' mysql> SELECT '2005-01-01' - INTERVAL 1 SECOND; -> '2004-12-31 23:59:59' mysql> SELECT DATE_ADD('2000-12-31 23:59:59', -> INTERVAL 1 SECOND); -> '2001-01-01 00:00:00' mysql> SELECT DATE_ADD('2010-12-31 23:59:59', -> INTERVAL 1 DAY); -> '2011-01-01 23:59:59' mysql> SELECT DATE_ADD('2100-12-31 23:59:59', -> INTERVAL '1:1' MINUTE_SECOND); -> '2101-01-01 00:01:00' mysql> SELECT DATE_SUB('2005-01-01 00:00:00', -> INTERVAL '1 1:1:1' DAY_SECOND); -> '2004-12-30 22:58:59' mysql> SELECT DATE_ADD('1900-01-01 00:00:00', -> INTERVAL '-1 10' DAY_HOUR); -> '1899-12-30 14:00:00' mysql> SELECT DATE_SUB('1998-01-02', INTERVAL 31 DAY); -> '1997-12-02' mysql> SELECT DATE_ADD('1992-12-31 23:59:59.000002', -> INTERVAL '1.999999' SECOND_MICROSECOND); -> '1993-01-01 00:00:01.000001' If you specify an interval value that is too short (does not include all the interval parts that would be expected from the UNIT keyword), MySQL assumes that you have left out the leftmost parts of the interval value. For example, if you specify a UNIT of `DAY_SECOND', the value of EXPR is expected to have days, hours, minutes, and seconds parts. If you specify a value like `'1:10'', MySQL assumes that the days and hours parts are missing and the value represents minutes and seconds. In other words, `'1:10' DAY_SECOND' is interpreted in such a way that it is equivalent to `'1:10' MINUTE_SECOND'. This is analogous to the way that MySQL interprets *Note `TIME': time. values as representing elapsed time rather than as a time of day. Because EXPR is treated as a string, be careful if you specify a nonstring value with `INTERVAL'. For example, with an interval specifier of `HOUR_MINUTE', `6/4' evaluates to `1.5000' and is treated as 1 hour, 5000 minutes: mysql> SELECT 6/4; -> 1.5000 mysql> SELECT DATE_ADD('2009-01-01', INTERVAL 6/4 HOUR_MINUTE); -> '2009-01-04 12:20:00' To ensure interpretation of the interval value as you expect, a `CAST()' operation may be used. To treat `6/4' as 1 hour, 5 minutes, cast it to a *Note `DECIMAL': numeric-types. value with a single fractional digit: mysql> SELECT CAST(6/4 AS DECIMAL(3,1)); -> 1.5 mysql> SELECT DATE_ADD('1970-01-01 12:00:00', -> INTERVAL CAST(6/4 AS DECIMAL(3,1)) HOUR_MINUTE); -> '1970-01-01 13:05:00' If you add to or subtract from a date value something that contains a time part, the result is automatically converted to a datetime value: mysql> SELECT DATE_ADD('2013-01-01', INTERVAL 1 DAY); -> '2013-01-02' mysql> SELECT DATE_ADD('2013-01-01', INTERVAL 1 HOUR); -> '2013-01-01 01:00:00' If you add `MONTH', `YEAR_MONTH', or `YEAR' and the resulting date has a day that is larger than the maximum day for the new month, the day is adjusted to the maximum days in the new month: mysql> SELECT DATE_ADD('2009-01-30', INTERVAL 1 MONTH); -> '2009-02-28' Date arithmetic operations require complete dates and do not work with incomplete dates such as `'2006-07-00'' or badly malformed dates: mysql> SELECT DATE_ADD('2006-07-00', INTERVAL 1 DAY); -> NULL mysql> SELECT '2005-03-32' + INTERVAL 1 MONTH; -> NULL * `DATE_FORMAT(DATE,FORMAT)' Formats the DATE value according to the FORMAT string. The following specifiers may be used in the FORMAT string. The ``%'' character is required before format specifier characters. Specifier Description `%a' Abbreviated weekday name (`Sun'..`Sat') `%b' Abbreviated month name (`Jan'..`Dec') `%c' Month, numeric (`0'..`12') `%D' Day of the month with English suffix (`0th', `1st', `2nd', `3rd', ...) `%d' Day of the month, numeric (`00'..`31') `%e' Day of the month, numeric (`0'..`31') `%f' Microseconds (`000000'..`999999') `%H' Hour (`00'..`23') `%h' Hour (`01'..`12') `%I' Hour (`01'..`12') `%i' Minutes, numeric (`00'..`59') `%j' Day of year (`001'..`366') `%k' Hour (`0'..`23') `%l' Hour (`1'..`12') `%M' Month name (`January'..`December') `%m' Month, numeric (`00'..`12') `%p' `AM' or `PM' `%r' Time, 12-hour (`hh:mm:ss' followed by `AM' or `PM') `%S' Seconds (`00'..`59') `%s' Seconds (`00'..`59') `%T' Time, 24-hour (`hh:mm:ss') `%U' Week (`00'..`53'), where Sunday is the first day of the week `%u' Week (`00'..`53'), where Monday is the first day of the week `%V' Week (`01'..`53'), where Sunday is the first day of the week; used with `%X' `%v' Week (`01'..`53'), where Monday is the first day of the week; used with `%x' `%W' Weekday name (`Sunday'..`Saturday') `%w' Day of the week (`0'=Sunday..`6'=Saturday) `%X' Year for the week where Sunday is the first day of the week, numeric, four digits; used with `%V' `%x' Year for the week, where Monday is the first day of the week, numeric, four digits; used with `%v' `%Y' Year, numeric, four digits `%y' Year, numeric (two digits) `%%' A literal ``%'' character `%X' X, for any `X' not listed above Ranges for the month and day specifiers begin with zero due to the fact that MySQL permits the storing of incomplete dates such as `'2014-00-00''. As of MySQL 5.1.12, the language used for day and month names and abbreviations is controlled by the value of the `lc_time_names' system variable (*Note locale-support::). As of MySQL 5.1.15, `DATE_FORMAT()' returns a string with a character set and collation given by `character_set_connection' and `collation_connection' so that it can return month and weekday names containing non-ASCII characters. Before 5.1.15, the return value is a binary string. mysql> SELECT DATE_FORMAT('2009-10-04 22:23:00', '%W %M %Y'); -> 'Sunday October 2009' mysql> SELECT DATE_FORMAT('2007-10-04 22:23:00', '%H:%i:%s'); -> '22:23:00' mysql> SELECT DATE_FORMAT('1900-10-04 22:23:00', -> '%D %y %a %d %m %b %j'); -> '4th 00 Thu 04 10 Oct 277' mysql> SELECT DATE_FORMAT('1997-10-04 22:23:00', -> '%H %k %I %r %T %S %w'); -> '22 22 10 10:23:00 PM 22:23:00 00 6' mysql> SELECT DATE_FORMAT('1999-01-01', '%X %V'); -> '1998 52' mysql> SELECT DATE_FORMAT('2006-06-00', '%d'); -> '00' * `DATE_SUB(DATE,INTERVAL EXPR UNIT)' See the description for `DATE_ADD()'. * `DAY(DATE)' `DAY()' is a synonym for `DAYOFMONTH()'. * `DAYNAME(DATE)' Returns the name of the weekday for DATE. As of MySQL 5.1.12, the language used for the name is controlled by the value of the `lc_time_names' system variable (*Note locale-support::). mysql> SELECT DAYNAME('2007-02-03'); -> 'Saturday' * `DAYOFMONTH(DATE)' Returns the day of the month for DATE, in the range `1' to `31', or `0' for dates such as `'0000-00-00'' or `'2008-00-00'' that have a zero day part. mysql> SELECT DAYOFMONTH('2007-02-03'); -> 3 * `DAYOFWEEK(DATE)' Returns the weekday index for DATE (`1' = Sunday, `2' = Monday, ..., `7' = Saturday). These index values correspond to the ODBC standard. mysql> SELECT DAYOFWEEK('2007-02-03'); -> 7 * `DAYOFYEAR(DATE)' Returns the day of the year for DATE, in the range `1' to `366'. mysql> SELECT DAYOFYEAR('2007-02-03'); -> 34 * `EXTRACT(UNIT FROM DATE)' The `EXTRACT()' function uses the same kinds of unit specifiers as `DATE_ADD()' or `DATE_SUB()', but extracts parts from the date rather than performing date arithmetic. mysql> SELECT EXTRACT(YEAR FROM '2009-07-02'); -> 2009 mysql> SELECT EXTRACT(YEAR_MONTH FROM '2009-07-02 01:02:03'); -> 200907 mysql> SELECT EXTRACT(DAY_MINUTE FROM '2009-07-02 01:02:03'); -> 20102 mysql> SELECT EXTRACT(MICROSECOND -> FROM '2003-01-02 10:30:00.000123'); -> 123 * `FROM_DAYS(N)' Given a day number N, returns a *Note `DATE': datetime. value. mysql> SELECT FROM_DAYS(730669); -> '2007-07-03' Use `FROM_DAYS()' with caution on old dates. It is not intended for use with values that precede the advent of the Gregorian calendar (1582). See *Note mysql-calendar::. * `FROM_UNIXTIME(UNIX_TIMESTAMP)', `FROM_UNIXTIME(UNIX_TIMESTAMP,FORMAT)' Returns a representation of the UNIX_TIMESTAMP argument as a value in `'YYYY-MM-DD HH:MM:SS'' or `YYYYMMDDHHMMSS.uuuuuu' format, depending on whether the function is used in a string or numeric context. The value is expressed in the current time zone. UNIX_TIMESTAMP is an internal timestamp value such as is produced by the `UNIX_TIMESTAMP()' function. If FORMAT is given, the result is formatted according to the FORMAT string, which is used the same way as listed in the entry for the `DATE_FORMAT()' function. mysql> SELECT FROM_UNIXTIME(1196440219); -> '2007-11-30 10:30:19' mysql> SELECT FROM_UNIXTIME(1196440219) + 0; -> 20071130103019.000000 mysql> SELECT FROM_UNIXTIME(UNIX_TIMESTAMP(), -> '%Y %D %M %h:%i:%s %x'); -> '2007 30th November 10:30:59 2007' Note: If you use `UNIX_TIMESTAMP()' and `FROM_UNIXTIME()' to convert between *Note `TIMESTAMP': datetime. values and Unix timestamp values, the conversion is lossy because the mapping is not one-to-one in both directions. For details, see the description of the `UNIX_TIMESTAMP()' function. * `GET_FORMAT({DATE|TIME|DATETIME}, {'EUR'|'USA'|'JIS'|'ISO'|'INTERNAL'})' Returns a format string. This function is useful in combination with the `DATE_FORMAT()' and the `STR_TO_DATE()' functions. The possible values for the first and second arguments result in several possible format strings (for the specifiers used, see the table in the `DATE_FORMAT()' function description). ISO format refers to ISO 9075, not ISO 8601. Function Call Result `GET_FORMAT(DATE,'USA')' `'%m.%d.%Y'' `GET_FORMAT(DATE,'JIS')' `'%Y-%m-%d'' `GET_FORMAT(DATE,'ISO')' `'%Y-%m-%d'' `GET_FORMAT(DATE,'EUR')' `'%d.%m.%Y'' `GET_FORMAT(DATE,'INTERNAL')' `'%Y%m%d'' `GET_FORMAT(DATETIME,'USA')' `'%Y-%m-%d %H.%i.%s'' `GET_FORMAT(DATETIME,'JIS')' `'%Y-%m-%d %H:%i:%s'' `GET_FORMAT(DATETIME,'ISO')' `'%Y-%m-%d %H:%i:%s'' `GET_FORMAT(DATETIME,'EUR')' `'%Y-%m-%d %H.%i.%s'' `GET_FORMAT(DATETIME,'INTERNAL')' `'%Y%m%d%H%i%s'' `GET_FORMAT(TIME,'USA')' `'%h:%i:%s %p'' `GET_FORMAT(TIME,'JIS')' `'%H:%i:%s'' `GET_FORMAT(TIME,'ISO')' `'%H:%i:%s'' `GET_FORMAT(TIME,'EUR')' `'%H.%i.%s'' `GET_FORMAT(TIME,'INTERNAL')' `'%H%i%s'' *Note `TIMESTAMP': datetime. can also be used as the first argument to `GET_FORMAT()', in which case the function returns the same values as for *Note `DATETIME': datetime. mysql> SELECT DATE_FORMAT('2003-10-03',GET_FORMAT(DATE,'EUR')); -> '03.10.2003' mysql> SELECT STR_TO_DATE('10.31.2003',GET_FORMAT(DATE,'USA')); -> '2003-10-31' * `HOUR(TIME)' Returns the hour for TIME. The range of the return value is `0' to `23' for time-of-day values. However, the range of *Note `TIME': time. values actually is much larger, so `HOUR' can return values greater than `23'. mysql> SELECT HOUR('10:05:03'); -> 10 mysql> SELECT HOUR('272:59:59'); -> 272 * `LAST_DAY(DATE)' Takes a date or datetime value and returns the corresponding value for the last day of the month. Returns `NULL' if the argument is invalid. mysql> SELECT LAST_DAY('2003-02-05'); -> '2003-02-28' mysql> SELECT LAST_DAY('2004-02-05'); -> '2004-02-29' mysql> SELECT LAST_DAY('2004-01-01 01:01:01'); -> '2004-01-31' mysql> SELECT LAST_DAY('2003-03-32'); -> NULL * `LOCALTIME', `LOCALTIME()' `LOCALTIME' and `LOCALTIME()' are synonyms for `NOW()'. * `LOCALTIMESTAMP', `LOCALTIMESTAMP()' `LOCALTIMESTAMP' and `LOCALTIMESTAMP()' are synonyms for `NOW()'. * `MAKEDATE(YEAR,DAYOFYEAR)' Returns a date, given year and day-of-year values. DAYOFYEAR must be greater than 0 or the result is `NULL'. mysql> SELECT MAKEDATE(2011,31), MAKEDATE(2011,32); -> '2011-01-31', '2011-02-01' mysql> SELECT MAKEDATE(2011,365), MAKEDATE(2014,365); -> '2011-12-31', '2014-12-31' mysql> SELECT MAKEDATE(2011,0); -> NULL * `MAKETIME(HOUR,MINUTE,SECOND)' Returns a time value calculated from the HOUR, MINUTE, and SECOND arguments. mysql> SELECT MAKETIME(12,15,30); -> '12:15:30' * `MICROSECOND(EXPR)' Returns the microseconds from the time or datetime expression EXPR as a number in the range from `0' to `999999'. mysql> SELECT MICROSECOND('12:00:00.123456'); -> 123456 mysql> SELECT MICROSECOND('2009-12-31 23:59:59.000010'); -> 10 * `MINUTE(TIME)' Returns the minute for TIME, in the range `0' to `59'. mysql> SELECT MINUTE('2008-02-03 10:05:03'); -> 5 * `MONTH(DATE)' Returns the month for DATE, in the range `1' to `12' for January to December, or `0' for dates such as `'0000-00-00'' or `'2008-00-00'' that have a zero month part. mysql> SELECT MONTH('2008-02-03'); -> 2 * `MONTHNAME(DATE)' Returns the full name of the month for DATE. As of MySQL 5.1.12, the language used for the name is controlled by the value of the `lc_time_names' system variable (*Note locale-support::). mysql> SELECT MONTHNAME('2008-02-03'); -> 'February' * `NOW()' Returns the current date and time as a value in `'YYYY-MM-DD HH:MM:SS'' or `YYYYMMDDHHMMSS.uuuuuu' format, depending on whether the function is used in a string or numeric context. The value is expressed in the current time zone. mysql> SELECT NOW(); -> '2007-12-15 23:50:26' mysql> SELECT NOW() + 0; -> 20071215235026.000000 `NOW()' returns a constant time that indicates the time at which the statement began to execute. (Within a stored function or trigger, `NOW()' returns the time at which the function or triggering statement began to execute.) This differs from the behavior for `SYSDATE()', which returns the exact time at which it executes. mysql> SELECT NOW(), SLEEP(2), NOW(); +---------------------+----------+---------------------+ | NOW() | SLEEP(2) | NOW() | +---------------------+----------+---------------------+ | 2006-04-12 13:47:36 | 0 | 2006-04-12 13:47:36 | +---------------------+----------+---------------------+ mysql> SELECT SYSDATE(), SLEEP(2), SYSDATE(); +---------------------+----------+---------------------+ | SYSDATE() | SLEEP(2) | SYSDATE() | +---------------------+----------+---------------------+ | 2006-04-12 13:47:44 | 0 | 2006-04-12 13:47:46 | +---------------------+----------+---------------------+ In addition, the `SET TIMESTAMP' statement affects the value returned by `NOW()' but not by `SYSDATE()'. This means that timestamp settings in the binary log have no effect on invocations of `SYSDATE()'. See the description for `SYSDATE()' for additional information about the differences between the two functions. * `PERIOD_ADD(P,N)' Adds N months to period P (in the format `YYMM' or `YYYYMM'). Returns a value in the format `YYYYMM'. Note that the period argument P is _not_ a date value. mysql> SELECT PERIOD_ADD(200801,2); -> 200803 * `PERIOD_DIFF(P1,P2)' Returns the number of months between periods P1 and P2. P1 and P2 should be in the format `YYMM' or `YYYYMM'. Note that the period arguments P1 and P2 are _not_ date values. mysql> SELECT PERIOD_DIFF(200802,200703); -> 11 * `QUARTER(DATE)' Returns the quarter of the year for DATE, in the range `1' to `4'. mysql> SELECT QUARTER('2008-04-01'); -> 2 * `SECOND(TIME)' Returns the second for TIME, in the range `0' to `59'. mysql> SELECT SECOND('10:05:03'); -> 3 * `SEC_TO_TIME(SECONDS)' Returns the SECONDS argument, converted to hours, minutes, and seconds, as a *Note `TIME': time. value. The range of the result is constrained to that of the *Note `TIME': time. data type. A warning occurs if the argument corresponds to a value outside that range. mysql> SELECT SEC_TO_TIME(2378); -> '00:39:38' mysql> SELECT SEC_TO_TIME(2378) + 0; -> 3938 * `STR_TO_DATE(STR,FORMAT)' This is the inverse of the `DATE_FORMAT()' function. It takes a string STR and a format string FORMAT. `STR_TO_DATE()' returns a *Note `DATETIME': datetime. value if the format string contains both date and time parts, or a *Note `DATE': datetime. or *Note `TIME': time. value if the string contains only date or time parts. If the date, time, or datetime value extracted from STR is illegal, `STR_TO_DATE()' returns `NULL' and produces a warning. The server scans STR attempting to match FORMAT to it. The format string can contain literal characters and format specifiers beginning with `%'. Literal characters in FORMAT must match literally in STR. Format specifiers in FORMAT must match a date or time part in STR. For the specifiers that can be used in FORMAT, see the `DATE_FORMAT()' function description. mysql> SELECT STR_TO_DATE('01,5,2013','%d,%m,%Y'); -> '2013-05-01' mysql> SELECT STR_TO_DATE('May 1, 2013','%M %d,%Y'); -> '2013-05-01' Scanning starts at the beginning of STR and fails if FORMAT is found not to match. Extra characters at the end of STR are ignored. mysql> SELECT STR_TO_DATE('a09:30:17','a%h:%i:%s'); -> '09:30:17' mysql> SELECT STR_TO_DATE('a09:30:17','%h:%i:%s'); -> NULL mysql> SELECT STR_TO_DATE('09:30:17a','%h:%i:%s'); -> '09:30:17' Unspecified date or time parts have a value of 0, so incompletely specified values in STR produce a result with some or all parts set to 0: mysql> SELECT STR_TO_DATE('abc','abc'); -> '0000-00-00' mysql> SELECT STR_TO_DATE('9','%m'); -> '0000-09-00' mysql> SELECT STR_TO_DATE('9','%s'); -> '00:00:09' Range checking on the parts of date values is as described in *Note datetime::. This means, for example, that `zero' dates or dates with part values of 0 are permitted unless the SQL mode is set to disallow such values. mysql> SELECT STR_TO_DATE('00/00/0000', '%m/%d/%Y'); -> '0000-00-00' mysql> SELECT STR_TO_DATE('04/31/2004', '%m/%d/%Y'); -> '2004-04-31' *Note*: You cannot use format `"%X%V"' to convert a year-week string to a date because the combination of a year and week does not uniquely identify a year and month if the week crosses a month boundary. To convert a year-week to a date, you should also specify the weekday: mysql> SELECT STR_TO_DATE('200442 Monday', '%X%V %W'); -> '2004-10-18' * `SUBDATE(DATE,INTERVAL EXPR UNIT)', `SUBDATE(EXPR,DAYS)' When invoked with the `INTERVAL' form of the second argument, `SUBDATE()' is a synonym for `DATE_SUB()'. For information on the `INTERVAL' UNIT argument, see the discussion for `DATE_ADD()'. mysql> SELECT DATE_SUB('2008-01-02', INTERVAL 31 DAY); -> '2007-12-02' mysql> SELECT SUBDATE('2008-01-02', INTERVAL 31 DAY); -> '2007-12-02' The second form enables the use of an integer value for DAYS. In such cases, it is interpreted as the number of days to be subtracted from the date or datetime expression EXPR. mysql> SELECT SUBDATE('2008-01-02 12:00:00', 31); -> '2007-12-02 12:00:00' * `SUBTIME(EXPR1,EXPR2)' `SUBTIME()' returns EXPR1 - EXPR2 expressed as a value in the same format as EXPR1. EXPR1 is a time or datetime expression, and EXPR2 is a time expression. mysql> SELECT SUBTIME('2007-12-31 23:59:59.999999','1 1:1:1.000002'); -> '2007-12-30 22:58:58.999997' mysql> SELECT SUBTIME('01:00:00.999999', '02:00:00.999998'); -> '-00:59:59.999999' * `SYSDATE()' Returns the current date and time as a value in `'YYYY-MM-DD HH:MM:SS'' or `YYYYMMDDHHMMSS.uuuuuu' format, depending on whether the function is used in a string or numeric context. `SYSDATE()' returns the time at which it executes. This differs from the behavior for `NOW()', which returns a constant time that indicates the time at which the statement began to execute. (Within a stored function or trigger, `NOW()' returns the time at which the function or triggering statement began to execute.) mysql> SELECT NOW(), SLEEP(2), NOW(); +---------------------+----------+---------------------+ | NOW() | SLEEP(2) | NOW() | +---------------------+----------+---------------------+ | 2006-04-12 13:47:36 | 0 | 2006-04-12 13:47:36 | +---------------------+----------+---------------------+ mysql> SELECT SYSDATE(), SLEEP(2), SYSDATE(); +---------------------+----------+---------------------+ | SYSDATE() | SLEEP(2) | SYSDATE() | +---------------------+----------+---------------------+ | 2006-04-12 13:47:44 | 0 | 2006-04-12 13:47:46 | +---------------------+----------+---------------------+ In addition, the `SET TIMESTAMP' statement affects the value returned by `NOW()' but not by `SYSDATE()'. This means that timestamp settings in the binary log have no effect on invocations of `SYSDATE()'. Because `SYSDATE()' can return different values even within the same statement, and is not affected by `SET TIMESTAMP', it is nondeterministic and therefore unsafe for replication if statement-based binary logging is used. If that is a problem, you can use row-based logging. Alternatively, you can use the `--sysdate-is-now' option to cause `SYSDATE()' to be an alias for `NOW()'. This works if the option is used on both the master and the slave. The nondeterministic nature of `SYSDATE()' also means that indexes cannot be used for evaluating expressions that refer to it. Beginning with MySQL 5.1.42, a warning is logged if you use this function when `binlog_format' is set to `STATEMENT'. (Bug#47995) * `TIME(EXPR)' Extracts the time part of the time or datetime expression EXPR and returns it as a string. This function is unsafe for statement-based replication. Beginning with MySQL 5.1.42, a warning is logged if you use this function when `binlog_format' is set to `STATEMENT'. (Bug#47995) mysql> SELECT TIME('2003-12-31 01:02:03'); -> '01:02:03' mysql> SELECT TIME('2003-12-31 01:02:03.000123'); -> '01:02:03.000123' * `TIMEDIFF(EXPR1,EXPR2)' `TIMEDIFF()' returns EXPR1 - EXPR2 expressed as a time value. EXPR1 and EXPR2 are time or date-and-time expressions, but both must be of the same type. mysql> SELECT TIMEDIFF('2000:01:01 00:00:00', -> '2000:01:01 00:00:00.000001'); -> '-00:00:00.000001' mysql> SELECT TIMEDIFF('2008-12-31 23:59:59.000001', -> '2008-12-30 01:01:01.000002'); -> '46:58:57.999999' * `TIMESTAMP(EXPR)', `TIMESTAMP(EXPR1,EXPR2)' With a single argument, this function returns the date or datetime expression EXPR as a datetime value. With two arguments, it adds the time expression EXPR2 to the date or datetime expression EXPR1 and returns the result as a datetime value. mysql> SELECT TIMESTAMP('2003-12-31'); -> '2003-12-31 00:00:00' mysql> SELECT TIMESTAMP('2003-12-31 12:00:00','12:00:00'); -> '2004-01-01 00:00:00' * `TIMESTAMPADD(UNIT,INTERVAL,DATETIME_EXPR)' Adds the integer expression INTERVAL to the date or datetime expression DATETIME_EXPR. The unit for INTERVAL is given by the UNIT argument, which should be one of the following values: `FRAC_SECOND' (microseconds), `SECOND', `MINUTE', `HOUR', `DAY', `WEEK', `MONTH', `QUARTER', or `YEAR'. Beginning with MySQL 5.1.24, it is possible to use `MICROSECOND' in place of `FRAC_SECOND' with this function, and `FRAC_SECOND' is deprecated. `FRAC_SECOND' is removed in MySQL 5.5. The UNIT value may be specified using one of keywords as shown, or with a prefix of `SQL_TSI_'. For example, `DAY' and `SQL_TSI_DAY' both are legal. mysql> SELECT TIMESTAMPADD(MINUTE,1,'2003-01-02'); -> '2003-01-02 00:01:00' mysql> SELECT TIMESTAMPADD(WEEK,1,'2003-01-02'); -> '2003-01-09' * `TIMESTAMPDIFF(UNIT,DATETIME_EXPR1,DATETIME_EXPR2)' Returns DATETIME_EXPR2 - DATETIME_EXPR1, where DATETIME_EXPR1 and DATETIME_EXPR2 are date or datetime expressions. One expression may be a date and the other a datetime; a date value is treated as a datetime having the time part `'00:00:00'' where necessary. The unit for the result (an integer) is given by the UNIT argument. The legal values for UNIT are the same as those listed in the description of the `TIMESTAMPADD()' function. mysql> SELECT TIMESTAMPDIFF(MONTH,'2003-02-01','2003-05-01'); -> 3 mysql> SELECT TIMESTAMPDIFF(YEAR,'2002-05-01','2001-01-01'); -> -1 mysql> SELECT TIMESTAMPDIFF(MINUTE,'2003-02-01','2003-05-01 12:05:55'); -> 128885 *Note*: The order of the date or datetime arguments for this function is the opposite of that used with the `TIMESTAMP()' function when invoked with 2 arguments. * `TIME_FORMAT(TIME,FORMAT)' This is used like the `DATE_FORMAT()' function, but the FORMAT string may contain format specifiers only for hours, minutes, seconds, and microseconds. Other specifiers produce a `NULL' value or `0'. If the TIME value contains an hour part that is greater than `23', the `%H' and `%k' hour format specifiers produce a value larger than the usual range of `0..23'. The other hour format specifiers produce the hour value modulo 12. mysql> SELECT TIME_FORMAT('100:00:00', '%H %k %h %I %l'); -> '100 100 04 04 4' * `TIME_TO_SEC(TIME)' Returns the TIME argument, converted to seconds. mysql> SELECT TIME_TO_SEC('22:23:00'); -> 80580 mysql> SELECT TIME_TO_SEC('00:39:38'); -> 2378 * `TO_DAYS(DATE)' Given a date DATE, returns a day number (the number of days since year 0). mysql> SELECT TO_DAYS(950501); -> 728779 mysql> SELECT TO_DAYS('2007-10-07'); -> 733321 `TO_DAYS()' is not intended for use with values that precede the advent of the Gregorian calendar (1582), because it does not take into account the days that were lost when the calendar was changed. For dates before 1582 (and possibly a later year in other locales), results from this function are not reliable. See *Note mysql-calendar::, for details. Remember that MySQL converts two-digit year values in dates to four-digit form using the rules in *Note date-and-time-types::. For example, `'2008-10-07'' and `'08-10-07'' are seen as identical dates: mysql> SELECT TO_DAYS('2008-10-07'), TO_DAYS('08-10-07'); -> 733687, 733687 In MySQL, the zero date is defined as `'0000-00-00'', even though this date is itself considered invalid. This means that, for `'0000-00-00'' and `'0000-01-01'', `TO_DAYS()' returns the values shown here: mysql> SELECT TO_DAYS('0000-00-00'); +-----------------------+ | to_days('0000-00-00') | +-----------------------+ | NULL | +-----------------------+ 1 row in set, 1 warning (0.00 sec) mysql> SHOW WARNINGS; +---------+------+----------------------------------------+ | Level | Code | Message | +---------+------+----------------------------------------+ | Warning | 1292 | Incorrect datetime value: '0000-00-00' | +---------+------+----------------------------------------+ 1 row in set (0.00 sec) mysql> SELECT TO_DAYS('0000-01-01'); +-----------------------+ | to_days('0000-01-01') | +-----------------------+ | 1 | +-----------------------+ 1 row in set (0.00 sec) This is true whether or not the `ALLOW_INVALID_DATES' SQL server mode is enabled. * `UNIX_TIMESTAMP()', `UNIX_TIMESTAMP(DATE)' If called with no argument, returns a Unix timestamp (seconds since `'1970-01-01 00:00:00'' UTC) as an unsigned integer. If `UNIX_TIMESTAMP()' is called with a DATE argument, it returns the value of the argument as seconds since `'1970-01-01 00:00:00'' UTC. DATE may be a *Note `DATE': datetime. string, a *Note `DATETIME': datetime. string, a *Note `TIMESTAMP': datetime, or a number in the format `YYMMDD' or `YYYYMMDD'. The server interprets DATE as a value in the current time zone and converts it to an internal value in UTC. Clients can set their time zone as described in *Note time-zone-support::. mysql> SELECT UNIX_TIMESTAMP(); -> 1196440210 mysql> SELECT UNIX_TIMESTAMP('2007-11-30 10:30:19'); -> 1196440219 When `UNIX_TIMESTAMP()' is used on a *Note `TIMESTAMP': datetime. column, the function returns the internal timestamp value directly, with no implicit `string-to-Unix-timestamp' conversion. If you pass an out-of-range date to `UNIX_TIMESTAMP()', it returns `0'. Note: If you use `UNIX_TIMESTAMP()' and `FROM_UNIXTIME()' to convert between *Note `TIMESTAMP': datetime. values and Unix timestamp values, the conversion is lossy because the mapping is not one-to-one in both directions. For example, due to conventions for local time zone changes, it is possible for two `UNIX_TIMESTAMP()' to map two *Note `TIMESTAMP': datetime. values to the same Unix timestamp value. `FROM_UNIXTIME()' will map that value back to only one of the original *Note `TIMESTAMP': datetime. values. Here is an example, using *Note `TIMESTAMP': datetime. values in the `CET' time zone: mysql> SELECT UNIX_TIMESTAMP('2005-03-27 03:00:00'); +---------------------------------------+ | UNIX_TIMESTAMP('2005-03-27 03:00:00') | +---------------------------------------+ | 1111885200 | +---------------------------------------+ mysql> SELECT UNIX_TIMESTAMP('2005-03-27 02:00:00'); +---------------------------------------+ | UNIX_TIMESTAMP('2005-03-27 02:00:00') | +---------------------------------------+ | 1111885200 | +---------------------------------------+ mysql> SELECT FROM_UNIXTIME(1111885200); +---------------------------+ | FROM_UNIXTIME(1111885200) | +---------------------------+ | 2005-03-27 03:00:00 | +---------------------------+ If you want to subtract `UNIX_TIMESTAMP()' columns, you might want to cast the result to signed integers. See *Note cast-functions::. * `UTC_DATE', `UTC_DATE()' Returns the current UTC date as a value in `'YYYY-MM-DD'' or `YYYYMMDD' format, depending on whether the function is used in a string or numeric context. mysql> SELECT UTC_DATE(), UTC_DATE() + 0; -> '2003-08-14', 20030814 * `UTC_TIME', `UTC_TIME()' Returns the current UTC time as a value in `'HH:MM:SS'' or `HHMMSS.uuuuuu' format, depending on whether the function is used in a string or numeric context. mysql> SELECT UTC_TIME(), UTC_TIME() + 0; -> '18:07:53', 180753.000000 * `UTC_TIMESTAMP', `UTC_TIMESTAMP()' Returns the current UTC date and time as a value in `'YYYY-MM-DD HH:MM:SS'' or `YYYYMMDDHHMMSS.uuuuuu' format, depending on whether the function is used in a string or numeric context. mysql> SELECT UTC_TIMESTAMP(), UTC_TIMESTAMP() + 0; -> '2003-08-14 18:08:04', 20030814180804.000000 * `WEEK(DATE[,MODE])' This function returns the week number for DATE. The two-argument form of `WEEK()' enables you to specify whether the week starts on Sunday or Monday and whether the return value should be in the range from `0' to `53' or from `1' to `53'. If the MODE argument is omitted, the value of the `default_week_format' system variable is used. See *Note server-system-variables::. The following table describes how the MODE argument works. Mode First day of Range Week 1 is the first week ... week 0 Sunday 0-53 with a Sunday in this year 1 Monday 0-53 with more than 3 days this year 2 Sunday 1-53 with a Sunday in this year 3 Monday 1-53 with more than 3 days this year 4 Sunday 0-53 with more than 3 days this year 5 Monday 0-53 with a Monday in this year 6 Sunday 1-53 with more than 3 days this year 7 Monday 1-53 with a Monday in this year mysql> SELECT WEEK('2008-02-20'); -> 7 mysql> SELECT WEEK('2008-02-20',0); -> 7 mysql> SELECT WEEK('2008-02-20',1); -> 8 mysql> SELECT WEEK('2008-12-31',1); -> 53 Note that if a date falls in the last week of the previous year, MySQL returns `0' if you do not use `2', `3', `6', or `7' as the optional MODE argument: mysql> SELECT YEAR('2000-01-01'), WEEK('2000-01-01',0); -> 2000, 0 One might argue that MySQL should return `52' for the `WEEK()' function, because the given date actually occurs in the 52nd week of 1999. We decided to return `0' instead because we want the function to return `the week number in the given year.' This makes use of the `WEEK()' function reliable when combined with other functions that extract a date part from a date. If you would prefer the result to be evaluated with respect to the year that contains the first day of the week for the given date, use `0', `2', `5', or `7' as the optional MODE argument. mysql> SELECT WEEK('2000-01-01',2); -> 52 Alternatively, use the `YEARWEEK()' function: mysql> SELECT YEARWEEK('2000-01-01'); -> 199952 mysql> SELECT MID(YEARWEEK('2000-01-01'),5,2); -> '52' * `WEEKDAY(DATE)' Returns the weekday index for DATE (`0' = Monday, `1' = Tuesday, ... `6' = Sunday). mysql> SELECT WEEKDAY('2008-02-03 22:23:00'); -> 6 mysql> SELECT WEEKDAY('2007-11-06'); -> 1 * `WEEKOFYEAR(DATE)' Returns the calendar week of the date as a number in the range from `1' to `53'. `WEEKOFYEAR()' is a compatibility function that is equivalent to `WEEK(DATE,3)'. mysql> SELECT WEEKOFYEAR('2008-02-20'); -> 8 * `YEAR(DATE)' Returns the year for DATE, in the range `1000' to `9999', or `0' for the `zero' date. mysql> SELECT YEAR('1987-01-01'); -> 1987 * `YEARWEEK(DATE)', `YEARWEEK(DATE,MODE)' Returns year and week for a date. The MODE argument works exactly like the MODE argument to `WEEK()'. The year in the result may be different from the year in the date argument for the first and the last week of the year. mysql> SELECT YEARWEEK('1987-01-01'); -> 198653 Note that the week number is different from what the `WEEK()' function would return (`0') for optional arguments `0' or `1', as `WEEK()' then returns the week in the context of the given year.  File: manual.info, Node: mysql-calendar, Next: fulltext-search, Prev: date-and-time-functions, Up: functions 12.8 What Calendar Is Used By MySQL? ==================================== MySQL uses what is known as a _proleptic Gregorian calendar_. Every country that has switched from the Julian to the Gregorian calendar has had to discard at least ten days during the switch. To see how this works, consider the month of October 1582, when the first Julian-to-Gregorian switch occurred. Monday Tuesday Wednesday Thursday Friday Saturday Sunday 1 2 3 4 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 There are no dates between October 4 and October 15. This discontinuity is called the _cutover_. Any dates before the cutover are Julian, and any dates following the cutover are Gregorian. Dates during a cutover are nonexistent. A calendar applied to dates when it was not actually in use is called _proleptic_. Thus, if we assume there was never a cutover and Gregorian rules always rule, we have a proleptic Gregorian calendar. This is what is used by MySQL, as is required by standard SQL. For this reason, dates prior to the cutover stored as MySQL *Note `DATE': datetime. or *Note `DATETIME': datetime. values must be adjusted to compensate for the difference. It is important to realize that the cutover did not occur at the same time in all countries, and that the later it happened, the more days were lost. For example, in Great Britain, it took place in 1752, when Wednesday September 2 was followed by Thursday September 14. Russia remained on the Julian calendar until 1918, losing 13 days in the process, and what is popularly referred to as its `October Revolution' occurred in November according to the Gregorian calendar.  File: manual.info, Node: fulltext-search, Next: cast-functions, Prev: mysql-calendar, Up: functions 12.9 Full-Text Search Functions =============================== * Menu: * fulltext-natural-language:: Natural Language Full-Text Searches * fulltext-boolean:: Boolean Full-Text Searches * fulltext-query-expansion:: Full-Text Searches with Query Expansion * fulltext-stopwords:: Full-Text Stopwords * fulltext-restrictions:: Full-Text Restrictions * fulltext-fine-tuning:: Fine-Tuning MySQL Full-Text Search * full-text-adding-collation:: Adding a Collation for Full-Text Indexing `MATCH (COL1,COL2,...) AGAINST (EXPR [SEARCH_MODIFIER])' SEARCH_MODIFIER: { IN NATURAL LANGUAGE MODE | IN NATURAL LANGUAGE MODE WITH QUERY EXPANSION | IN BOOLEAN MODE | WITH QUERY EXPANSION } MySQL has support for full-text indexing and searching: * A full-text index in MySQL is an index of type `FULLTEXT'. * Full-text indexes can be used only with `MyISAM' tables, and can be created only for *Note `CHAR': char, *Note `VARCHAR': char, or *Note `TEXT': blob. columns. * A `FULLTEXT' index definition can be given in the *Note `CREATE TABLE': create-table. statement when a table is created, or added later using *Note `ALTER TABLE': alter-table. or *Note `CREATE INDEX': create-index. * For large data sets, it is much faster to load your data into a table that has no `FULLTEXT' index and then create the index after that, than to load data into a table that has an existing `FULLTEXT' index. Full-text searching is performed using `MATCH() ... AGAINST' syntax. `MATCH()' takes a comma-separated list that names the columns to be searched. `AGAINST' takes a string to search for, and an optional modifier that indicates what type of search to perform. The search string must be a literal string, not a variable or a column name. There are three types of full-text searches: * A natural language search interprets the search string as a phrase in natural human language (a phrase in free text). There are no special operators. The stopword list applies. In addition, words that are present in 50% or more of the rows are considered common and do not match. Full-text searches are natural language searches if the `IN NATURAL LANGUAGE MODE' modifier is given or if no modifier is given. For more information, see *Note fulltext-natural-language::. * A boolean search interprets the search string using the rules of a special query language. The string contains the words to search for. It can also contain operators that specify requirements such that a word must be present or absent in matching rows, or that it should be weighted higher or lower than usual. Common words such as `some' or `then' are stopwords and do not match if present in the search string. The `IN BOOLEAN MODE' modifier specifies a boolean search. For more information, see *Note fulltext-boolean::. * A query expansion search is a modification of a natural language search. The search string is used to perform a natural language search. Then words from the most relevant rows returned by the search are added to the search string and the search is done again. The query returns the rows from the second search. The `IN NATURAL LANGUAGE MODE WITH QUERY EXPANSION' or `WITH QUERY EXPANSION' modifier specifies a query expansion search. For more information, see *Note fulltext-query-expansion::. The `IN NATURAL LANGUAGE MODE' and `IN NATURAL LANGUAGE MODE WITH QUERY EXPANSION' modifiers were added in MySQL 5.1.7. Constraints on full-text searching are listed in *Note fulltext-restrictions::. The *Note `myisam_ftdump': myisam-ftdump. utility can be used to dump the contents of a full-text index. This may be helpful for debugging full-text queries. See *Note myisam-ftdump::.  File: manual.info, Node: fulltext-natural-language, Next: fulltext-boolean, Prev: fulltext-search, Up: fulltext-search 12.9.1 Natural Language Full-Text Searches ------------------------------------------ By default or with the `IN NATURAL LANGUAGE MODE' modifier, the `MATCH()' function performs a natural language search for a string against a _text collection_. A collection is a set of one or more columns included in a `FULLTEXT' index. The search string is given as the argument to `AGAINST()'. For each row in the table, `MATCH()' returns a relevance value; that is, a similarity measure between the search string and the text in that row in the columns named in the `MATCH()' list. mysql> CREATE TABLE articles ( -> id INT UNSIGNED AUTO_INCREMENT NOT NULL PRIMARY KEY, -> title VARCHAR(200), -> body TEXT, -> FULLTEXT (title,body) -> ) ENGINE=MyISAM; Query OK, 0 rows affected (0.00 sec) mysql> INSERT INTO articles (title,body) VALUES -> ('MySQL Tutorial','DBMS stands for DataBase ...'), -> ('How To Use MySQL Well','After you went through a ...'), -> ('Optimizing MySQL','In this tutorial we will show ...'), -> ('1001 MySQL Tricks','1. Never run mysqld as root. 2. ...'), -> ('MySQL vs. YourSQL','In the following database comparison ...'), -> ('MySQL Security','When configured properly, MySQL ...'); Query OK, 6 rows affected (0.00 sec) Records: 6 Duplicates: 0 Warnings: 0 mysql> SELECT * FROM articles -> WHERE MATCH (title,body) -> AGAINST ('database' IN NATURAL LANGUAGE MODE); +----+-------------------+------------------------------------------+ | id | title | body | +----+-------------------+------------------------------------------+ | 5 | MySQL vs. YourSQL | In the following database comparison ... | | 1 | MySQL Tutorial | DBMS stands for DataBase ... | +----+-------------------+------------------------------------------+ 2 rows in set (0.00 sec) By default, the search is performed in case-insensitive fashion. However, you can perform a case-sensitive full-text search by using a binary collation for the indexed columns. For example, a column that uses the `latin1' character set of can be assigned a collation of `latin1_bin' to make it case sensitive for full-text searches. When `MATCH()' is used in a `WHERE' clause, as in the example shown earlier, the rows returned are automatically sorted with the highest relevance first. Relevance values are nonnegative floating-point numbers. Zero relevance means no similarity. Relevance is computed based on the number of words in the row, the number of unique words in that row, the total number of words in the collection, and the number of documents (rows) that contain a particular word. To simply count matches, you could use a query like this: mysql> SELECT COUNT(*) FROM articles -> WHERE MATCH (title,body) -> AGAINST ('database' IN NATURAL LANGUAGE MODE); +----------+ | COUNT(*) | +----------+ | 2 | +----------+ 1 row in set (0.00 sec) However, you might find it quicker to rewrite the query as follows: mysql> SELECT -> COUNT(IF(MATCH (title,body) AGAINST ('database' IN NATURAL LANGUAGE MODE), 1, NULL)) -> AS count -> FROM articles; +-------+ | count | +-------+ | 2 | +-------+ 1 row in set (0.03 sec) The first query sorts the results by relevance whereas the second does not. However, the second query performs a full table scan and the first does not. The first may be faster if the search matches few rows; otherwise, the second may be faster because it would read many rows anyway. For natural-language full-text searches, it is a requirement that the columns named in the `MATCH()' function be the same columns included in some `FULLTEXT' index in your table. For the preceding query, note that the columns named in the `MATCH()' function (`title' and `body') are the same as those named in the definition of the `article' table's `FULLTEXT' index. If you wanted to search the `title' or `body' separately, you would need to create separate `FULLTEXT' indexes for each column. It is also possible to perform a boolean search or a search with query expansion. These search types are described in *Note fulltext-boolean::, and *Note fulltext-query-expansion::. A full-text search that uses an index can name columns only from a single table in the `MATCH()' clause because an index cannot span multiple tables. A boolean search can be done in the absence of an index (albeit more slowly), in which case it is possible to name columns from multiple tables. The preceding example is a basic illustration that shows how to use the `MATCH()' function where rows are returned in order of decreasing relevance. The next example shows how to retrieve the relevance values explicitly. Returned rows are not ordered because the *Note `SELECT': select. statement includes neither `WHERE' nor `ORDER BY' clauses: mysql> SELECT id, MATCH (title,body) -> AGAINST ('Tutorial' IN NATURAL LANGUAGE MODE) AS score -> FROM articles; +----+------------------+ | id | score | +----+------------------+ | 1 | 0.65545833110809 | | 2 | 0 | | 3 | 0.66266459226608 | | 4 | 0 | | 5 | 0 | | 6 | 0 | +----+------------------+ 6 rows in set (0.00 sec) The following example is more complex. The query returns the relevance values and it also sorts the rows in order of decreasing relevance. To achieve this result, you should specify `MATCH()' twice: once in the *Note `SELECT': select. list and once in the `WHERE' clause. This causes no additional overhead, because the MySQL optimizer notices that the two `MATCH()' calls are identical and invokes the full-text search code only once. mysql> SELECT id, body, MATCH (title,body) AGAINST -> ('Security implications of running MySQL as root' -> IN NATURAL LANGUAGE MODE) AS score -> FROM articles WHERE MATCH (title,body) AGAINST -> ('Security implications of running MySQL as root' -> IN NATURAL LANGUAGE MODE); +----+-------------------------------------+-----------------+ | id | body | score | +----+-------------------------------------+-----------------+ | 4 | 1. Never run mysqld as root. 2. ... | 1.5219271183014 | | 6 | When configured properly, MySQL ... | 1.3114095926285 | +----+-------------------------------------+-----------------+ 2 rows in set (0.00 sec) The MySQL `FULLTEXT' implementation regards any sequence of true word characters (letters, digits, and underscores) as a word. That sequence may also contain apostrophes (``'''), but not more than one in a row. This means that `aaa'bbb' is regarded as one word, but `aaa''bbb' is regarded as two words. Apostrophes at the beginning or the end of a word are stripped by the `FULLTEXT' parser; `'aaa'bbb'' would be parsed as `aaa'bbb'. The `FULLTEXT' parser determines where words start and end by looking for certain delimiter characters; for example, `` '' (space), ``,'' (comma), and ``.'' (period). If words are not separated by delimiters (as in, for example, Chinese), the `FULLTEXT' parser cannot determine where a word begins or ends. To be able to add words or other indexed terms in such languages to a `FULLTEXT' index, you must preprocess them so that they are separated by some arbitrary delimiter such as ``"''. In MySQL 5.1, it is possible to write a plugin that replaces the built-in full-text parser. For details, see *Note plugin-api::. For example parser plugin source code, see the `plugin/fulltext' directory of a MySQL source distribution. Some words are ignored in full-text searches: * Any word that is too short is ignored. The default minimum length of words that are found by full-text searches is four characters. * Words in the stopword list are ignored. A stopword is a word such as `the' or `some' that is so common that it is considered to have zero semantic value. There is a built-in stopword list, but it can be overwritten by a user-defined list. The default stopword list is given in *Note fulltext-stopwords::. The default minimum word length and stopword list can be changed as described in *Note fulltext-fine-tuning::. Every correct word in the collection and in the query is weighted according to its significance in the collection or query. Consequently, a word that is present in many documents has a lower weight (and may even have a zero weight), because it has lower semantic value in this particular collection. Conversely, if the word is rare, it receives a higher weight. The weights of the words are combined to compute the relevance of the row. Such a technique works best with large collections (in fact, it was carefully tuned this way). For very small tables, word distribution does not adequately reflect their semantic value, and this model may sometimes produce bizarre results. For example, although the word `MySQL' is present in every row of the `articles' table shown earlier, a search for the word produces no results: mysql> SELECT * FROM articles -> WHERE MATCH (title,body) -> AGAINST ('MySQL' IN NATURAL LANGUAGE MODE); Empty set (0.00 sec) The search result is empty because the word `MySQL' is present in at least 50% of the rows. As such, it is effectively treated as a stopword. For large data sets, this is the most desirable behavior: A natural language query should not return every second row from a 1GB table. For small data sets, it may be less desirable. A word that matches half of the rows in a table is less likely to locate relevant documents. In fact, it most likely finds plenty of irrelevant documents. We all know this happens far too often when we are trying to find something on the Internet with a search engine. It is with this reasoning that rows containing the word are assigned a low semantic value for _the particular data set in which they occur_. A given word may reach the 50% threshold in one data set but not another. The 50% threshold has a significant implication when you first try full-text searching to see how it works: If you create a table and insert only one or two rows of text into it, every word in the text occurs in at least 50% of the rows. As a result, no search returns any results. Be sure to insert at least three rows, and preferably many more. Users who need to bypass the 50% limitation can use the boolean search mode; see *Note fulltext-boolean::.  File: manual.info, Node: fulltext-boolean, Next: fulltext-query-expansion, Prev: fulltext-natural-language, Up: fulltext-search 12.9.2 Boolean Full-Text Searches --------------------------------- MySQL can perform boolean full-text searches using the `IN BOOLEAN MODE' modifier. With this modifier, certain characters have special meaning at the beginning or end of words in the search string. In the following query, the `+' and `-' operators indicate that a word is required to be present or absent, respectively, for a match to occur. Thus, the query retrieves all the rows that contain the word `MySQL' but that do _not_ contain the word `YourSQL': mysql> SELECT * FROM articles WHERE MATCH (title,body) -> AGAINST ('+MySQL -YourSQL' IN BOOLEAN MODE); +----+-----------------------+-------------------------------------+ | id | title | body | +----+-----------------------+-------------------------------------+ | 1 | MySQL Tutorial | DBMS stands for DataBase ... | | 2 | How To Use MySQL Well | After you went through a ... | | 3 | Optimizing MySQL | In this tutorial we will show ... | | 4 | 1001 MySQL Tricks | 1. Never run mysqld as root. 2. ... | | 6 | MySQL Security | When configured properly, MySQL ... | +----+-----------------------+-------------------------------------+ *Note*: In implementing this feature, MySQL uses what is sometimes referred to as _implied Boolean logic_, in which * `+' stands for `AND' * `-' stands for `NOT' * [_no operator_] implies `OR' Boolean full-text searches have these characteristics: * They do not use the 50% threshold. * They do not automatically sort rows in order of decreasing relevance. You can see this from the preceding query result: The row with the highest relevance is the one that contains `MySQL' twice, but it is listed last, not first. * They can work even without a `FULLTEXT' index, although a search executed in this fashion would be quite slow. * The minimum and maximum word length full-text parameters apply. * The stopword list applies. The boolean full-text search capability supports the following operators: * `+' A leading plus sign indicates that this word _must_ be present in each row that is returned. * `-' A leading minus sign indicates that this word must _not_ be present in any of the rows that are returned. Note: The `-' operator acts only to exclude rows that are otherwise matched by other search terms. Thus, a boolean-mode search that contains only terms preceded by `-' returns an empty result. It does not return `all rows except those containing any of the excluded terms.' * (no operator) By default (when neither `+' nor `-' is specified) the word is optional, but the rows that contain it are rated higher. This mimics the behavior of `MATCH() ... AGAINST()' without the `IN BOOLEAN MODE' modifier. * `> <' These two operators are used to change a word's contribution to the relevance value that is assigned to a row. The `>' operator increases the contribution and the `<' operator decreases it. See the example following this list. * `( )' Parentheses group words into subexpressions. Parenthesized groups can be nested. * `~' A leading tilde acts as a negation operator, causing the word's contribution to the row's relevance to be negative. This is useful for marking `noise' words. A row containing such a word is rated lower than others, but is not excluded altogether, as it would be with the `-' operator. * `*' The asterisk serves as the truncation (or wildcard) operator. Unlike the other operators, it should be _appended_ to the word to be affected. Words match if they begin with the word preceding the `*' operator. If a word is specified with the truncation operator, it is not stripped from a boolean query, even if it is too short (as determined from the `ft_min_word_len' setting) or a stopword. This occurs because the word is not seen as too short or a stopword, but as a prefix that must be present in the document in the form of a word that begins with the prefix. Suppose that `ft_min_word_len=4'. Then a search for `'+WORD +the*'' will likely return fewer rows than a search for `'+WORD +the'': * The former query remains as is and requires both WORD and `the*' (a word starting with `the') to be present in the document. * The latter query is transformed to `+WORD' (requiring only WORD to be present). `the' is both too short and a stopword, and either condition is enough to cause it to be ignored. * `"' A phrase that is enclosed within double quote (``"'') characters matches only rows that contain the phrase _literally, as it was typed_. The full-text engine splits the phrase into words and performs a search in the `FULLTEXT' index for the words. Nonword characters need not be matched exactly: Phrase searching requires only that matches contain exactly the same words as the phrase and in the same order. For example, `"test phrase"' matches `"test, phrase"'. If the phrase contains no words that are in the index, the result is empty. For example, if all words are either stopwords or shorter than the minimum length of indexed words, the result is empty. The following examples demonstrate some search strings that use boolean full-text operators: * `'apple banana'' Find rows that contain at least one of the two words. * `'+apple +juice'' Find rows that contain both words. * `'+apple macintosh'' Find rows that contain the word `apple', but rank rows higher if they also contain `macintosh'. * `'+apple -macintosh'' Find rows that contain the word `apple' but not `macintosh'. * `'+apple ~macintosh'' Find rows that contain the word `apple', but if the row also contains the word `macintosh', rate it lower than if row does not. This is `softer' than a search for `'+apple -macintosh'', for which the presence of `macintosh' causes the row not to be returned at all. * `'+apple +(>turnover SELECT * FROM articles -> WHERE MATCH (title,body) -> AGAINST ('database' IN NATURAL LANGUAGE MODE); +----+-------------------+------------------------------------------+ | id | title | body | +----+-------------------+------------------------------------------+ | 5 | MySQL vs. YourSQL | In the following database comparison ... | | 1 | MySQL Tutorial | DBMS stands for DataBase ... | +----+-------------------+------------------------------------------+ 2 rows in set (0.00 sec) mysql> SELECT * FROM articles -> WHERE MATCH (title,body) -> AGAINST ('database' WITH QUERY EXPANSION); +----+-------------------+------------------------------------------+ | id | title | body | +----+-------------------+------------------------------------------+ | 1 | MySQL Tutorial | DBMS stands for DataBase ... | | 5 | MySQL vs. YourSQL | In the following database comparison ... | | 3 | Optimizing MySQL | In this tutorial we will show ... | +----+-------------------+------------------------------------------+ 3 rows in set (0.00 sec) Another example could be searching for books by Georges Simenon about Maigret, when a user is not sure how to spell `Maigret'. A search for `Megre and the reluctant witnesses' finds only `Maigret and the Reluctant Witnesses' without query expansion. A search with query expansion finds all books with the word `Maigret' on the second pass. *Note*: Because blind query expansion tends to increase noise significantly by returning nonrelevant documents, it is meaningful to use only when a search phrase is rather short.  File: manual.info, Node: fulltext-stopwords, Next: fulltext-restrictions, Prev: fulltext-query-expansion, Up: fulltext-search 12.9.4 Full-Text Stopwords -------------------------- The stopword list is loaded and searched for full-text queries using the server character set and collation (the values of the `character_set_server' and `collation_server' system variables). False hits or misses may occur for stopword lookups if the stopword file or columns used for full-text indexing or searches have a character set or collation different from `character_set_server' or `collation_server'. Case sensitivity of stopword lookups depends on the server collation. For example, lookups are case insensitive if the collation is `latin1_swedish_ci', whereas lookups are case sensitive if the collation is `latin1_general_cs' or `latin1_bin'. The following table shows the default list of full-text stopwords. In a MySQL source distribution, you can find this list in the `storage/myisam/ft_static.c' file. a's able about above according accordingly across actually after afterwards again against ain't all allow allows almost alone along already also although always am among amongst an and another any anybody anyhow anyone anything anyway anyways anywhere apart appear appreciate appropriate are aren't around as aside ask asking associated at available away awfully be became because become becomes becoming been before beforehand behind being believe below beside besides best better between beyond both brief but by c'mon c's came can can't cannot cant cause causes certain certainly changes clearly co com come comes concerning consequently consider considering contain containing contains corresponding could couldn't course currently definitely described despite did didn't different do does doesn't doing don't done down downwards during each edu eg eight either else elsewhere enough entirely especially et etc even ever every everybody everyone everything everywhere ex exactly example except far few fifth first five followed following follows for former formerly forth four from further furthermore get gets getting given gives go goes going gone got gotten greetings had hadn't happens hardly has hasn't have haven't having he he's hello help hence her here here's hereafter hereby herein hereupon hers herself hi him himself his hither hopefully how howbeit however i'd i'll i'm i've ie if ignored immediate in inasmuch inc indeed indicate indicated indicates inner insofar instead into inward is isn't it it'd it'll it's its itself just keep keeps kept know known knows last lately later latter latterly least less lest let let's like liked likely little look looking looks ltd mainly many may maybe me mean meanwhile merely might more moreover most mostly much must my myself name namely nd near nearly necessary need needs neither never nevertheless new next nine no nobody non none noone nor normally not nothing novel now nowhere obviously of off often oh ok okay old on once one ones only onto or other others otherwise ought our ours ourselves out outside over overall own particular particularly per perhaps placed please plus possible presumably probably provides que quite qv rather rd re really reasonably regarding regardless regards relatively respectively right said same saw say saying says second secondly see seeing seem seemed seeming seems seen self selves sensible sent serious seriously seven several shall she should shouldn't since six so some somebody somehow someone something sometime sometimes somewhat somewhere soon sorry specified specify specifying still sub such sup sure t's take taken tell tends th than thank thanks thanx that that's thats the their theirs them themselves then thence there there's thereafter thereby therefore therein theres thereupon these they they'd they'll they're they've think third this thorough thoroughly those though three through throughout thru thus to together too took toward towards tried tries truly try trying twice two un under unfortunately unless unlikely until unto up upon us use used useful uses using usually value various very via viz vs want wants was wasn't way we we'd we'll we're we've welcome well went were weren't what what's whatever when whence whenever where where's whereafter whereas whereby wherein whereupon wherever whether which while whither who who's whoever whole whom whose why will willing wish with within without won't wonder would wouldn't yes yet you you'd you'll you're you've your yours yourself yourselves zero  File: manual.info, Node: fulltext-restrictions, Next: fulltext-fine-tuning, Prev: fulltext-stopwords, Up: fulltext-search 12.9.5 Full-Text Restrictions ----------------------------- * Full-text searches are supported for `MyISAM' tables only. * Full-text searches can be used with most multi-byte character sets. The exception is that for Unicode, the `utf8' character set can be used, but not the `ucs2' character set. However, although `FULLTEXT' indexes on `ucs2' columns cannot be used, you can perform `IN BOOLEAN MODE' searches on a `ucs2' column that has no such index. * Ideographic languages such as Chinese and Japanese do not have word delimiters. Therefore, the `FULLTEXT' parser _cannot determine where words begin and end in these and other such languages_. The implications of this and some workarounds for the problem are described in *Note fulltext-search::. * Although the use of multiple character sets within a single table is supported, all columns in a `FULLTEXT' index must use the same character set and collation. * The `MATCH()' column list must match exactly the column list in some `FULLTEXT' index definition for the table, unless this `MATCH()' is `IN BOOLEAN MODE'. Boolean-mode searches can be done on nonindexed columns, although they are likely to be slow. * The argument to `AGAINST()' must be a constant string. * Index hints are more limited for `FULLTEXT' searches than for non-`FULLTEXT' searches. See *Note index-hints::.  File: manual.info, Node: fulltext-fine-tuning, Next: full-text-adding-collation, Prev: fulltext-restrictions, Up: fulltext-search 12.9.6 Fine-Tuning MySQL Full-Text Search ----------------------------------------- MySQL's full-text search capability has few user-tunable parameters. You can exert more control over full-text searching behavior if you have a MySQL source distribution because some changes require source code modifications. See *Note source-installation::. Note that full-text search is carefully tuned for the most effectiveness. Modifying the default behavior in most cases can actually decrease effectiveness. _Do not alter the MySQL sources unless you know what you are doing_. Most full-text variables described in this section must be set at server startup time. A server restart is required to change them; they cannot be modified while the server is running. Some variable changes require that you rebuild the `FULLTEXT' indexes in your tables. Instructions for doing so are given later in this section. * The minimum and maximum lengths of words to be indexed are defined by the `ft_min_word_len' and `ft_max_word_len' system variables. (See *Note server-system-variables::.) The default minimum value is four characters; the default maximum is version dependent. If you change either value, you must rebuild your `FULLTEXT' indexes. For example, if you want three-character words to be searchable, you can set the `ft_min_word_len' variable by putting the following lines in an option file: [mysqld] ft_min_word_len=3 Then restart the server and rebuild your `FULLTEXT' indexes. Note particularly the remarks regarding *Note `myisamchk': myisamchk. in the instructions following this list. * To override the default stopword list, set the `ft_stopword_file' system variable. (See *Note server-system-variables::.) The variable value should be the path name of the file containing the stopword list, or the empty string to disable stopword filtering. The server looks for the file in the data directory unless an absolute path name is given to specify a different directory. After changing the value of this variable or the contents of the stopword file, restart the server and rebuild your `FULLTEXT' indexes. The stopword list is free-form. That is, you may use any nonalphanumeric character such as newline, space, or comma to separate stopwords. Exceptions are the underscore character (``_'') and a single apostrophe (``''') which are treated as part of a word. The character set of the stopword list is the server's default character set; see *Note charset-server::. * The 50% threshold for natural language searches is determined by the particular weighting scheme chosen. To disable it, look for the following line in `storage/myisam/ftdefs.h': #define GWS_IN_USE GWS_PROB Change that line to this: #define GWS_IN_USE GWS_FREQ Then recompile MySQL. There is no need to rebuild the indexes in this case. *Note*: By making this change, you _severely_ decrease MySQL's ability to provide adequate relevance values for the `MATCH()' function. If you really need to search for such common words, it would be better to search using `IN BOOLEAN MODE' instead, which does not observe the 50% threshold. * To change the operators used for boolean full-text searches, set the `ft_boolean_syntax' system variable. This variable can be changed while the server is running, but you must have the `SUPER' privilege to do so. No rebuilding of indexes is necessary in this case. See *Note server-system-variables::, which describes the rules governing how to set this variable. * If you want to change the set of characters that are considered word characters, you can do so in several ways, as described in the following list. After making the modification, you must rebuild the indexes for each table that contains any `FULLTEXT' indexes. Suppose that you want to treat the hyphen character ('-') as a word character. Use one of these methods: * Modify the MySQL source: In `storage/myisam/ftdefs.h', see the `true_word_char()' and `misc_word_char()' macros. Add `'-'' to one of those macros and recompile MySQL. * Modify a character set file: This requires no recompilation. The `true_word_char()' macro uses a `character type' table to distinguish letters and numbers from other characters. . You can edit the contents of the `' array in one of the character set XML files to specify that `'-'' is a `letter.' Then use the given character set for your `FULLTEXT' indexes. For information about the `' array format, see *Note character-arrays::. * Add a new collation for the character set used by the indexed columns, and alter the columns to use that collation. For general information about adding collations, see *Note adding-collation::. For an example specific to full-text indexing, see *Note full-text-adding-collation::. If you modify full-text variables that affect indexing (`ft_min_word_len', `ft_max_word_len', or `ft_stopword_file'), or if you change the stopword file itself, you must rebuild your `FULLTEXT' indexes after making the changes and restarting the server. To rebuild the indexes in this case, it is sufficient to do a `QUICK' repair operation: mysql> REPAIR TABLE TBL_NAME QUICK; Alternatively, use *Note `ALTER TABLE': alter-table. with the `DROP INDEX' and `ADD INDEX' options to drop and re-create each `FULLTEXT' index. In some cases, this may be faster than a repair operation. Each table that contains any `FULLTEXT' index must be repaired as just shown. Otherwise, queries for the table may yield incorrect results, and modifications to the table will cause the server to see the table as corrupt and in need of repair. Note that if you use *Note `myisamchk': myisamchk. to perform an operation that modifies table indexes (such as repair or analyze), the `FULLTEXT' indexes are rebuilt using the _default_ full-text parameter values for minimum word length, maximum word length, and stopword file unless you specify otherwise. This can result in queries failing. The problem occurs because these parameters are known only by the server. They are not stored in `MyISAM' index files. To avoid the problem if you have modified the minimum or maximum word length or stopword file values used by the server, specify the same `ft_min_word_len', `ft_max_word_len', and `ft_stopword_file' values for *Note `myisamchk': myisamchk. that you use for *Note `mysqld': mysqld. For example, if you have set the minimum word length to 3, you can repair a table with *Note `myisamchk': myisamchk. like this: shell> myisamchk --recover --ft_min_word_len=3 TBL_NAME.MYI To ensure that *Note `myisamchk': myisamchk. and the server use the same values for full-text parameters, place each one in both the `[mysqld]' and `[myisamchk]' sections of an option file: [mysqld] ft_min_word_len=3 [myisamchk] ft_min_word_len=3 An alternative to using *Note `myisamchk': myisamchk. for index modification is to use the *Note `REPAIR TABLE': repair-table, *Note `ANALYZE TABLE': analyze-table, *Note `OPTIMIZE TABLE': optimize-table, or *Note `ALTER TABLE': alter-table. statements. These statements are performed by the server, which knows the proper full-text parameter values to use.  File: manual.info, Node: full-text-adding-collation, Prev: fulltext-fine-tuning, Up: fulltext-search 12.9.7 Adding a Collation for Full-Text Indexing ------------------------------------------------ This section describes how to add a new collation for full-text searches. The sample collation is like `latin1_swedish_ci' but treats the `'-'' character as a letter rather than as a punctuation character so that it can be indexed as a word character. General information about adding collations is given in *Note adding-collation::; it is assumed that you have read it and are familiar with the files involved. To add a collation for full-text indexing, use this procedure: 1. Add a collation to the `Index.xml' file. The collation ID must be unused, so choose a value different from 62 if that ID is already taken on your system. ... 2. Declare the sort order for the collation in the `latin1.xml' file. In this case, the order can be copied from `latin1_swedish_ci': 00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F 10 11 12 13 14 15 16 17 18 19 1A 1B 1C 1D 1E 1F 20 21 22 23 24 25 26 27 28 29 2A 2B 2C 2D 2E 2F 30 31 32 33 34 35 36 37 38 39 3A 3B 3C 3D 3E 3F 40 41 42 43 44 45 46 47 48 49 4A 4B 4C 4D 4E 4F 50 51 52 53 54 55 56 57 58 59 5A 5B 5C 5D 5E 5F 60 41 42 43 44 45 46 47 48 49 4A 4B 4C 4D 4E 4F 50 51 52 53 54 55 56 57 58 59 5A 7B 7C 7D 7E 7F 80 81 82 83 84 85 86 87 88 89 8A 8B 8C 8D 8E 8F 90 91 92 93 94 95 96 97 98 99 9A 9B 9C 9D 9E 9F A0 A1 A2 A3 A4 A5 A6 A7 A8 A9 AA AB AC AD AE AF B0 B1 B2 B3 B4 B5 B6 B7 B8 B9 BA BB BC BD BE BF 41 41 41 41 5C 5B 5C 43 45 45 45 45 49 49 49 49 44 4E 4F 4F 4F 4F 5D D7 D8 55 55 55 59 59 DE DF 41 41 41 41 5C 5B 5C 43 45 45 45 45 49 49 49 49 44 4E 4F 4F 4F 4F 5D F7 D8 55 55 55 59 59 DE FF 3. Modify the `ctype' array in `latin1.xml'. Change the value corresponding to 0x2D (which is the code for the `'-'' character) from 10 (punctuation) to 01 (small letter). In the following array, this is the element in the fourth row down, third value from the end. 00 20 20 20 20 20 20 20 20 20 28 28 28 28 28 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 48 10 10 10 10 10 10 10 10 10 10 10 10 *01* 10 10 84 84 84 84 84 84 84 84 84 84 10 10 10 10 10 10 10 81 81 81 81 81 81 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01 10 10 10 10 10 10 82 82 82 82 82 82 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 10 10 10 10 20 10 00 10 02 10 10 10 10 10 10 01 10 01 00 01 00 00 10 10 10 10 10 10 10 10 10 02 10 02 00 02 01 48 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01 10 01 01 01 01 01 01 01 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 10 02 02 02 02 02 02 02 02 4. Restart the server. 5. To employ the new collation, include it in the definition of columns that are to use it: mysql> DROP TABLE IF EXISTS t1; Query OK, 0 rows affected (0.13 sec) mysql> CREATE TABLE t1 ( -> a TEXT CHARACTER SET latin1 COLLATE latin1_fulltext_ci, -> FULLTEXT INDEX(a) -> ) ENGINE=MyISAM; Query OK, 0 rows affected (0.47 sec) 6. Test the collation to verify that hyphen is considered as a word character: mysql> INSERT INTO t1 VALUEs ('----'),('....'),('abcd'); Query OK, 3 rows affected (0.22 sec) Records: 3 Duplicates: 0 Warnings: 0 mysql> SELECT * FROM t1 WHERE MATCH a AGAINST ('----' IN BOOLEAN MODE); +------+ | a | +------+ | ---- | +------+ 1 row in set (0.00 sec)  File: manual.info, Node: cast-functions, Next: xml-functions, Prev: fulltext-search, Up: functions 12.10 Cast Functions and Operators ================================== *Cast Functions* Name Description `BINARY' Cast a string to a binary string `CAST()' Cast a value as a certain type `Convert()' Cast a value as a certain type * `BINARY' The `BINARY' operator casts the string following it to a binary string. This is an easy way to force a column comparison to be done byte by byte rather than character by character. This causes the comparison to be case sensitive even if the column is not defined as *Note `BINARY': binary-varbinary. or *Note `BLOB': blob. `BINARY' also causes trailing spaces to be significant. mysql> SELECT 'a' = 'A'; -> 1 mysql> SELECT BINARY 'a' = 'A'; -> 0 mysql> SELECT 'a' = 'a '; -> 1 mysql> SELECT BINARY 'a' = 'a '; -> 0 In a comparison, `BINARY' affects the entire operation; it can be given before either operand with the same result. `BINARY STR' is shorthand for `CAST(STR AS BINARY)'. Note that in some contexts, if you cast an indexed column to `BINARY', MySQL is not able to use the index efficiently. * `CAST(EXPR AS TYPE)' The `CAST()' function takes a value of one type and produce a value of another type, similar to `CONVERT()'. See the description of `CONVERT()' for more information. * `CONVERT(EXPR,TYPE)', `CONVERT(EXPR USING TRANSCODING_NAME)' The `CONVERT()' and `CAST()' functions take a value of one type and produce a value of another type. The TYPE can be one of the following values: * `BINARY[(N)]' * `CHAR[(N)]' * *Note `DATE': datetime. * *Note `DATETIME': datetime. * `DECIMAL[(M[,D])]' * `SIGNED [INTEGER]' * *Note `TIME': time. * `UNSIGNED [INTEGER]' *Note `BINARY': binary-varbinary. produces a string with the *Note `BINARY': binary-varbinary. data type. See *Note binary-varbinary:: for a description of how this affects comparisons. If the optional length N is given, `BINARY(N)' causes the cast to use no more than N bytes of the argument. Values shorter than N bytes are padded with `0x00' bytes to a length of N. `CHAR(N)' causes the cast to use no more than N characters of the argument. `CAST()' and `CONVERT(... USING ...)' are standard SQL syntax. The non-`USING' form of `CONVERT()' is ODBC syntax. `CONVERT()' with `USING' is used to convert data between different character sets. In MySQL, transcoding names are the same as the corresponding character set names. For example, this statement converts the string `'abc'' in the default character set to the corresponding string in the `utf8' character set: SELECT CONVERT('abc' USING utf8); Normally, you cannot compare a *Note `BLOB': blob. value or other binary string in case-insensitive fashion because binary strings have no character set, and thus no concept of lettercase. To perform a case-insensitive comparison, use the `CONVERT()' function to convert the value to a nonbinary string. Comparisons of the result use the string collation. For example, if the character set of the result has a case-insensitive collation, a `LIKE' operation is not case sensitive: SELECT 'A' LIKE CONVERT(BLOB_COL USING latin1) FROM TBL_NAME; To use a different character set, substitute its name for `latin1' in the preceding statement. To specify a particular collation for the converted string, use a `COLLATE' clause following the `CONVERT()' call, as described in *Note charset-convert::. For example, to use `latin1_german1_ci': SELECT 'A' LIKE CONVERT(BLOB_COL USING latin1) COLLATE latin1_german1_ci FROM TBL_NAME; `CONVERT()' can be used more generally for comparing strings that are represented in different character sets. `LOWER()' (and `UPPER()') are ineffective when applied to binary strings (*Note `BINARY': binary-varbinary, *Note `VARBINARY': binary-varbinary, *Note `BLOB': blob.). To perform lettercase conversion, convert the string to a nonbinary string: mysql> SET @str = BINARY 'New York'; mysql> SELECT LOWER(@str), LOWER(CONVERT(@str USING latin1)); +-------------+-----------------------------------+ | LOWER(@str) | LOWER(CONVERT(@str USING latin1)) | +-------------+-----------------------------------+ | New York | new york | +-------------+-----------------------------------+ The cast functions are useful when you want to create a column with a specific type in a *Note `CREATE TABLE ... SELECT': create-table. statement: CREATE TABLE new_table SELECT CAST('2000-01-01' AS DATE); The functions also can be useful for sorting *Note `ENUM': enum. columns in lexical order. Normally, sorting of *Note `ENUM': enum. columns occurs using the internal numeric values. Casting the values to *Note `CHAR': char. results in a lexical sort: SELECT ENUM_COL FROM TBL_NAME ORDER BY CAST(ENUM_COL AS CHAR); `CAST(STR AS BINARY)' is the same thing as `BINARY STR'. `CAST(EXPR AS CHAR)' treats the expression as a string with the default character set. `CAST()' also changes the result if you use it as part of a more complex expression such as `CONCAT('Date: ',CAST(NOW() AS DATE))'. You should not use `CAST()' to extract data in different formats but instead use string functions like `LEFT()' or `EXTRACT()'. See *Note date-and-time-functions::. To cast a string to a numeric value in numeric context, you normally do not have to do anything other than to use the string value as though it were a number: mysql> SELECT 1+'1'; -> 2 If you use a string in an arithmetic operation, it is converted to a floating-point number during expression evaluation. If you use a number in string context, the number automatically is converted to a string: mysql> SELECT CONCAT('hello you ',2); -> 'hello you 2' For information about implicit conversion of numbers to strings, see *Note type-conversion::. MySQL supports arithmetic with both signed and unsigned 64-bit values. If you are using numeric operators (such as `+' or `-') and one of the operands is an unsigned integer, the result is unsigned by default (see *Note arithmetic-functions::). You can override this by using the `SIGNED' or `UNSIGNED' cast operator to cast a value to a signed or unsigned 64-bit integer, respectively. mysql> SELECT CAST(1-2 AS UNSIGNED) -> 18446744073709551615 mysql> SELECT CAST(CAST(1-2 AS UNSIGNED) AS SIGNED); -> -1 If either operand is a floating-point value, the result is a floating-point value and is not affected by the preceding rule. (In this context, *Note `DECIMAL': numeric-types. column values are regarded as floating-point values.) mysql> SELECT CAST(1 AS UNSIGNED) - 2.0; -> -1.0 The SQL mode affects the result of conversion operations. Examples: * If you convert a `zero' date string to a date, `CONVERT()' and `CAST()' return `NULL' and produce a warning when the `NO_ZERO_DATE' SQL mode is enabled. * For integer subtraction, if the `NO_UNSIGNED_SUBTRACTION' SQL mode is enabled, the subtraction result is signed even if any operand is unsigned. For more information, see *Note server-sql-mode::.  File: manual.info, Node: xml-functions, Next: bit-functions, Prev: cast-functions, Up: functions 12.11 XML Functions =================== *XML Functions* Name Description `ExtractValue()' Extracts a value from an XML string using XPath notation `UpdateXML()' Return replaced XML fragment This section discusses XML and related functionality in MySQL. *Note*: It is possible to obtain XML-formatted output from MySQL in the *Note `mysql': mysql. and *Note `mysqldump': mysqldump. clients by invoking them with the `--xml' option. See *Note mysql::, and *Note mysqldump::. Beginning with MySQL 5.1.5, two functions providing basic XPath 1.0 (XML Path Language, version 1.0) capabilities are available. Some basic information about XPath syntax and usage is provided later in this section; however, an in-depth discussion of these topics is beyond the scope of this Manual, and you should refer to the XML Path Language (XPath) 1.0 standard (http://www.w3.org/TR/xpath) for definitive information. A useful resource for those new to XPath or who desire a refresher in the basics is the Zvon.org XPath Tutorial (http://www.zvon.org/xxl/XPathTutorial/), which is available in several languages. *Note*: These functions remain under development. We continue to improve these and other aspects of XML and XPath functionality in MySQL 5.1 and onwards. You may discuss these, ask questions about them, and obtain help from other users with them in the MySQL XML User Forum (http://forums.mysql.com/list.php?44). Beginning with MySQL 5.1.20, XPath expressions used with these functions support user variables and local stored program variables. User variables are weakly checked; variables local to stored programs are strongly checked (see also Bug#26518): * User variables (weak checking) Variables using the syntax `$@VARIABLE_NAME' (that is, user variables) are not checked. No warnings or errors are issued by the server if a variable has the wrong type or has previously not been assigned a value. This also means the user is fully responsible for any typographical errors, since no warnings will be given if (for example) `$@myvairable' is used where `$@myvariable' was intended. Example: mysql> SET @xml = 'XY'; Query OK, 0 rows affected (0.00 sec) mysql> SET @i =1, @j = 2; Query OK, 0 rows affected (0.00 sec) mysql> SELECT @i, ExtractValue(@xml, '//b[$@i]'); +------+--------------------------------+ | @i | ExtractValue(@xml, '//b[$@i]') | +------+--------------------------------+ | 1 | X | +------+--------------------------------+ 1 row in set (0.00 sec) mysql> SELECT @j, ExtractValue(@xml, '//b[$@j]'); +------+--------------------------------+ | @j | ExtractValue(@xml, '//b[$@j]') | +------+--------------------------------+ | 2 | Y | +------+--------------------------------+ 1 row in set (0.00 sec) mysql> SELECT @k, ExtractValue(@xml, '//b[$@k]'); +------+--------------------------------+ | @k | ExtractValue(@xml, '//b[$@k]') | +------+--------------------------------+ | NULL | | +------+--------------------------------+ 1 row in set (0.00 sec) * Variables in stored programs (strong checking) Variables using the syntax `$VARIABLE_NAME' can be declared and used with these functions when they are called inside stored programs. Such variables are local to the stored program in which they are defined, and are strongly checked for type and value. Example: mysql> DELIMITER | mysql> CREATE PROCEDURE myproc () -> BEGIN -> DECLARE i INT DEFAULT 1; -> DECLARE xml VARCHAR(25) DEFAULT 'XYZ'; -> -> WHILE i < 4 DO -> SELECT xml, i, ExtractValue(xml, '//a[$i]'); -> SET i = i+1; -> END WHILE; -> END | Query OK, 0 rows affected (0.01 sec) mysql> DELIMITER ; mysql> CALL myproc; +--------------------------+---+------------------------------+ | xml | i | ExtractValue(xml, '//a[$i]') | +--------------------------+---+------------------------------+ | XYZ | 1 | X | +--------------------------+---+------------------------------+ 1 row in set (0.00 sec) +--------------------------+---+------------------------------+ | xml | i | ExtractValue(xml, '//a[$i]') | +--------------------------+---+------------------------------+ | XYZ | 2 | Y | +--------------------------+---+------------------------------+ 1 row in set (0.01 sec) +--------------------------+---+------------------------------+ | xml | i | ExtractValue(xml, '//a[$i]') | +--------------------------+---+------------------------------+ | XYZ | 3 | Z | +--------------------------+---+------------------------------+ 1 row in set (0.01 sec) Parameters Variables used in XPath expressions inside stored routines that are passed in as parameters are also subject to strong checking. Expressions containing user variables or variables local to stored programs must otherwise (except for notation) conform to the rules for XPath expressions containing variables as given in the XPath 1.0 specification. *Note*: Currently, a user variable used to store an XPath expression is treated as an empty string. Because of this, it is not possible to store an XPath expression as a user variable. (Bug#32911) * `ExtractValue(XML_FRAG, XPATH_EXPR)' `ExtractValue()' takes two string arguments, a fragment of XML markup XML_FRAG and an XPath expression XPATH_EXPR (also known as a _locator_); it returns the text (`CDATA') of the first text node which is a child of the element(s) matched by the XPath expression. It is the equivalent of performing a match using the XPATH_EXPR after appending `/text()'. In other words, `ExtractValue('Sakila', '/a/b')' and `ExtractValue('Sakila', '/a/b/text()')' produce the same result. If multiple matches are found, the content of the first child text node of each matching element is returned (in the order matched) as a single, space-delimited string. If no matching text node is found for the expression (including the implicit `/text()')--for whatever reason, as long as XPATH_EXPR is valid, and XML_FRAG consists of elements which are properly nested and closed--an empty string is returned. No distinction is made between a match on an empty element and no match at all. This is by design. If you need to determine whether no matching element was found in XML_FRAG or such an element was found but contained no child text nodes, you should test the result of an expression that uses the XPath `count()' function. For example, both of these statements return an empty string, as shown here: mysql> SELECT ExtractValue('', '/a/b'); +-------------------------------------+ | ExtractValue('', '/a/b') | +-------------------------------------+ | | +-------------------------------------+ 1 row in set (0.00 sec) mysql> SELECT ExtractValue('', '/a/b'); +-------------------------------------+ | ExtractValue('', '/a/b') | +-------------------------------------+ | | +-------------------------------------+ 1 row in set (0.00 sec) However, you can determine whether there was actually a matching element using the following: mysql> SELECT ExtractValue('', 'count(/a/b)'); +-------------------------------------+ | ExtractValue('', 'count(/a/b)') | +-------------------------------------+ | 1 | +-------------------------------------+ 1 row in set (0.00 sec) mysql> SELECT ExtractValue('', 'count(/a/b)'); +-------------------------------------+ | ExtractValue('', 'count(/a/b)') | +-------------------------------------+ | 0 | +-------------------------------------+ 1 row in set (0.01 sec) *Important*: `ExtractValue()' returns only `CDATA', and does not return any tags that might be contained within a matching tag, nor any of their content (see the result returned as `val1' in the following example). mysql> SELECT -> ExtractValue('cccddd', '/a') AS val1, -> ExtractValue('cccddd', '/a/b') AS val2, -> ExtractValue('cccddd', '//b') AS val3, -> ExtractValue('cccddd', '/b') AS val4, -> ExtractValue('cccdddeee', '//b') AS val5; +------+------+------+------+---------+ | val1 | val2 | val3 | val4 | val5 | +------+------+------+------+---------+ | ccc | ddd | ddd | | ddd eee | +------+------+------+------+---------+ Beginning with MySQL 5.1.8, this function uses the current SQL collation for making comparisons with `contains()', performing the same collation aggregation as other string functions (such as `CONCAT()'), in taking into account the collation coercibility of their arguments; see *Note charset-collation-expressions::, for an explanation of the rules governing this behavior. (Previously, binary--that is, case-sensitive--comparison was always used.) Beginning with MySQL 5.1.12, `NULL' is returned if XML_FRAG contains elements which are not properly nested or closed, and a warning is generated, as shown in this example: mysql> SELECT ExtractValue('cc SHOW WARNINGS; +---------+------+-------------------------------------------------------------------------------------------+ | Level | Code | Message | +---------+------+-------------------------------------------------------------------------------------------+ | Warning | 1523 | Incorrect XML value: 'parse error at line 1 pos 11: END-OF-INPUT unexpected ('>' wanted)' | +---------+------+-------------------------------------------------------------------------------------------+ 1 row in set (0.00 sec) mysql> SELECT ExtractValue('c', '//a'); +-------------------------------------+ | ExtractValue('c', '//a') | +-------------------------------------+ | c | +-------------------------------------+ 1 row in set (0.00 sec) Prior to MySQL 5.1.12, an empty string was returned in such cases. (Bug#18201) * `UpdateXML(XML_TARGET, XPATH_EXPR, NEW_XML)' This function replaces a single portion of a given fragment of XML markup XML_TARGET with a new XML fragment NEW_XML, and then returns the changed XML. The portion of XML_TARGET that is replaced matches an XPath expression XPATH_EXPR supplied by the user. If no expression matching XPATH_EXPR is found, or if multiple matches are found, the function returns the original XML_TARGET XML fragment. All three arguments should be strings. mysql> SELECT -> UpdateXML('ccc', '/a', 'fff') AS val1, -> UpdateXML('ccc', '/b', 'fff') AS val2, -> UpdateXML('ccc', '//b', 'fff') AS val3, -> UpdateXML('ccc', '/a/d', 'fff') AS val4, -> UpdateXML('ccc', '/a/d', 'fff') AS val5 -> \G *************************** 1. row *************************** val1: fff val2: ccc val3: fff val4: cccfff val5: ccc *Note*: A discussion in depth of XPath syntax and usage are beyond the scope of this Manual. Please see the XML Path Language (XPath) 1.0 specification (http://www.w3.org/TR/xpath) for definitive information. A useful resource for those new to XPath or who are wishing a refresher in the basics is the Zvon.org XPath Tutorial (http://www.zvon.org/xxl/XPathTutorial/), which is available in several languages. Descriptions and examples of some basic XPath expressions follow: * `/TAG' Matches `' if and only if `' is the root element. Example: `/a' has a match in `' because it matches the outermost (root) tag. It does not match the inner A element in `' because in this instance it is the child of another element. * `/TAG1/TAG2' Matches `' if and only if it is a child of `', and `' is the root element. Example: `/a/b' matches the B element in the XML fragment `' because it is a child of the root element A. It does not have a match in `' because in this case, B is the root element (and hence the child of no other element). Nor does the XPath expression have a match in `'; here, B is a descendant of A, but not actually a child of A. This construct is extendable to three or more elements. For example, the XPath expression `/a/b/c' matches the C element in the fragment `'. * `//TAG' Matches any instance of `'. Example: `//a' matches the A element in any of the following: `'; `'; `'. `//' can be combined with `/'. For example, `//a/b' matches the B element in either of the fragments `' or `' *Note*: `//TAG' is the equivalent of `/descendant-or-self::*/TAG'. A common error is to confuse this with `/descendant-or-self::TAG', although the latter expression can actually lead to very different results, as can be seen here: mysql> SET @xml = 'wxyz'; Query OK, 0 rows affected (0.00 sec) mysql> SELECT @xml; +-----------------------------------------+ | @xml | +-----------------------------------------+ | wxyz | +-----------------------------------------+ 1 row in set (0.00 sec) mysql> SELECT ExtractValue(@xml, '//b[1]'); +------------------------------+ | ExtractValue(@xml, '//b[1]') | +------------------------------+ | x z | +------------------------------+ 1 row in set (0.00 sec) mysql> SELECT ExtractValue(@xml, '//b[2]'); +------------------------------+ | ExtractValue(@xml, '//b[2]') | +------------------------------+ | | +------------------------------+ 1 row in set (0.01 sec) mysql> SELECT ExtractValue(@xml, '/descendant-or-self::*/b[1]'); +---------------------------------------------------+ | ExtractValue(@xml, '/descendant-or-self::*/b[1]') | +---------------------------------------------------+ | x z | +---------------------------------------------------+ 1 row in set (0.06 sec) mysql> SELECT ExtractValue(@xml, '/descendant-or-self::*/b[2]'); +---------------------------------------------------+ | ExtractValue(@xml, '/descendant-or-self::*/b[2]') | +---------------------------------------------------+ | | +---------------------------------------------------+ 1 row in set (0.00 sec) mysql> SELECT ExtractValue(@xml, '/descendant-or-self::b[1]'); +-------------------------------------------------+ | ExtractValue(@xml, '/descendant-or-self::b[1]') | +-------------------------------------------------+ | z | +-------------------------------------------------+ 1 row in set (0.00 sec) mysql> SELECT ExtractValue(@xml, '/descendant-or-self::b[2]'); +-------------------------------------------------+ | ExtractValue(@xml, '/descendant-or-self::b[2]') | +-------------------------------------------------+ | x | +-------------------------------------------------+ 1 row in set (0.00 sec) * The `*' operator acts as a `wildcard' that matches any element. For example, the expression `/*/b' matches the B element in either of the XML fragments `' or `'. However, the expression does not produce a match in the fragment `' because B must be a child of some other element. The wildcard may be used in any position: The expression `/*/b/*' will match any child of a B element that is itself not the root element. * You can match any of several locators using the `|' (*Note `UNION': union.) operator. For example, the expression `//b|//c' matches all B and C elements in the XML target. * It is also possible to match an element based on the value of one or more of its attributes. This done using the syntax `TAG[@ATTRIBUTE="VALUE"]'. For example, the expression `//b[@id="idB"]' matches the second B element in the fragment `'. To match against _any_ element having `ATTRIBUTE="VALUE"', use the XPath expression `//*[ATTRIBUTE="VALUE"]'. To filter multiple attribute values, simply use multiple attribute-comparison clauses in succession. For example, the expression `//b[@c="x"][@d="y"]' matches the element `' occurring anywhere in a given XML fragment. To find elements for which the same attribute matches any of several values, you can use multiple locators joined by the `|' operator. For example, to match all B elements whose C attributes have either of the values 23 or 17, use the expression `//b[@c="23"]|//b[@c="17"]'. You can also use the logical `or' operator for this purpose: `//b[@c="23" or @c="17"]'. *Note*: The difference between `or' and `|' is that `or' joins conditions, while `|' joins result sets. XPath Limitations The XPath syntax supported by these functions is currently subject to the following limitations: * Nodeset-to-nodeset comparison (such as `'/a/b[@c=@d]'') is not supported. * Prior to MySQL 5.1.14, equality and inequality (`=' and `!=') were the only supported comparison operators. Beginning with MySQL 5.1.14, all of the standard XPath comparison operators are supported. (Bug#22823) * Relative locator expressions are resolved in the context of the root node. For example, consider the following query and result: mysql> SELECT ExtractValue( -> 'XY', -> 'a/b' -> ) AS result; +--------+ | result | +--------+ | X Y | +--------+ 1 row in set (0.03 sec) In this case, the locator `a/b' resolves to `/a/b'. Relative locators are also supported within predicates. In the following example, `d[../@c="1"]' is resolved as `/a/b[@c="1"]/d': mysql> SELECT ExtractValue( -> ' -> X -> X -> ', -> 'a/b/d[../@c="1"]') -> AS result; +--------+ | result | +--------+ | X | +--------+ 1 row in set (0.00 sec) * Locators prefixed with expressions that evaluate as scalar values--including variable references, literals, numbers, and scalar function calls--are not supported. Beginning with MySQL 5.1.32, they are not permitted, and their use results in an error. (Bug#42495) * The `::' operator is not supported in combination with node types such as the following: * `AXIS::comment()' * `AXIS::text()' * `AXIS::processing-instructions()' * `AXIS::node()' However, name tests (such as `AXIS::NAME' and `AXIS::*') are supported, as shown in these examples: mysql> SELECT ExtractValue('xy','/a/child::b'); +-------------------------------------------------------+ | ExtractValue('xy','/a/child::b') | +-------------------------------------------------------+ | x | +-------------------------------------------------------+ 1 row in set (0.02 sec) mysql> SELECT ExtractValue('xy','/a/child::*'); +-------------------------------------------------------+ | ExtractValue('xy','/a/child::*') | +-------------------------------------------------------+ | x y | +-------------------------------------------------------+ 1 row in set (0.01 sec) * `Up-and-down' navigation is not supported in cases where the path would lead `above' the root element. That is, you cannot use expressions which match on descendants of ancestors of a given element, where one or more of the ancestors of the current element is also an ancestor of the root element (see Bug#16321). * The following XPath functions are not supported, or have known issues as indicated: * Prior to MySQL 5.1.24, the `boolean()' function did not produce correct results for some string and nodeset values, including the `NULL' string (see Bug#26051). * `id()' * `lang()' * Prior to MySQL 5.1.8, the `last()' function was not supported (see Bug#16318). * `local-name()' * `name()' * `namespace-uri()' * `normalize-space()' * `starts-with()' * `string()' * `substring-after()' * `substring-before()' * `translate()' * The following axes are not supported: * `following-sibling' * `following' * `preceding-sibling' * `preceding' Beginning with MySQL 5.1.10, XPath expressions passed as arguments to `ExtractValue()' and `UpdateXML()' may contain the colon character (``:'') in element selectors, which enables their use with markup employing XML namespaces notation. For example: mysql> SET @xml = '111222333444'; Query OK, 0 rows affected (0.00 sec) mysql> SELECT ExtractValue(@xml, '//e:f'); +-----------------------------+ | ExtractValue(@xml, '//e:f') | +-----------------------------+ | 444 | +-----------------------------+ 1 row in set (0.00 sec) mysql> SELECT UpdateXML(@xml, '//b:c', '555'); +--------------------------------------------+ | UpdateXML(@xml, '//b:c', '555') | +--------------------------------------------+ | 111555 | +--------------------------------------------+ 1 row in set (0.00 sec) This is similar in some respects to what is permitted by Apache Xalan (http://xalan.apache.org/) and some other parsers, and is much simpler than requiring namespace declarations or the use of the `namespace-uri()' and `local-name()' functions. Error handling For both `ExtractValue()' and `UpdateXML()', the XPath locator used must be valid and the XML to be searched must consist of elements which are properly nested and closed. If the locator is invalid, an error is generated: mysql> SELECT ExtractValue('c', '/&a'); `ERROR 1105 (HY000): XPATH syntax error: '&a'' If XML_FRAG does not consist of elements which are properly nested and closed, `NULL' is returned and a warning is generated, as shown in this example: mysql> SELECT ExtractValue('cc SHOW WARNINGS; +---------+------+-------------------------------------------------------------------------------------------+ | Level | Code | Message | +---------+------+-------------------------------------------------------------------------------------------+ | Warning | 1523 | Incorrect XML value: 'parse error at line 1 pos 11: END-OF-INPUT unexpected ('>' wanted)' | +---------+------+-------------------------------------------------------------------------------------------+ 1 row in set (0.00 sec) mysql> SELECT ExtractValue('c', '//a'); +-------------------------------------+ | ExtractValue('c', '//a') | +-------------------------------------+ | c | +-------------------------------------+ 1 row in set (0.00 sec) Prior to MySQL 5.1.12, an empty string was returned in such cases. (Bug#18201) *Important*: The replacement XML used as the third argument to `UpdateXML()' is _not_ checked to determine whether it consists solely of elements which are properly nested and closed. XPath Injection _code injection_ occurs when malicious code is introduced into the system to gain unauthorized access to privileges and data. It is based on exploiting assumptions made by developers about the type and content of data input from users. XPath is no exception in this regard. A common scenario in which this can happen is the case of application which handles authorization by matching the combination of a login name and password with those found in an XML file, using an XPath expression like this one: //user[login/text()='neapolitan' and password/text()='1c3cr34m']/attribute::id This is the XPath equivalent of an SQL statement like this one: SELECT id FROM users WHERE login='neapolitan' AND password='1c3cr34m'; A PHP application employing XPath might handle the login process like this: xpath($xpath)) echo "You are now logged in as user $result[0]."; else echo "Invalid login name or password."; } else exit("Failed to open $file."); ?> No checks are performed on the input. This means that a malevolent user can `short-circuit' the test by entering `' or 1=1' for both the login name and password, resulting in $xpath being evaluated as shown here: //user[login/text()='' or 1=1 and password/text()='' or 1=1]/attribute::id Since the expression inside the square brackets always evaluates as `true', it is effectively the same as this one, which matches the `id' attribute of every `user' element in the XML document: //user/attribute::id One way in which this particular attack can be circumvented is simply by quoting the variable names to be interpolated in the definition of `$xpath', forcing the values passed from a Web form to be converted to strings: $xpath = "//user[login/text()='$login' and password/text()='$password']/attribute::id"; This is the same strategy that is often recommended for preventing SQL injection attacks. In general, the practices you should follow for preventing XPath injection attacks are the same as for preventing SQL injection: * Never accepted untested data from users in your application. * Check all user-submitted data for type; reject or convert data that is of the wrong type * Test numeric data for out of range values; truncate, round, or reject values that are out of range. Test strings for illegal characters and either strip them out or reject input containing them. * Do not output explicit error messages that might provide an unauthorized user with clues that could be used to compromise the system; log these to a file or database table instead. Just as SQL injection attacks can be used to obtain information about database schemas, so can XPath injection be used to traverse XML files to uncover their structure, as discussed in Amit Klein's paper Blind XPath Injection (http://www.packetstormsecurity.org/papers/bypass/Blind_XPath_Injection_20040518.pdf) (PDF file, 46KB). It is also important to check the output being sent back to the client. Consider what can happen when we use the MySQL `ExtractValue()' function: mysql> SELECT ExtractValue( -> LOAD_FILE('users.xml'), -> '//user[login/text()="" or 1=1 and password/text()="" or 1=1]/attribute::id' -> ) AS id; +-------------------------------+ | id | +-------------------------------+ | 00327 13579 02403 42354 28570 | +-------------------------------+ 1 row in set (0.01 sec) Because `ExtractValue()' returns multiple matches as a single space-delimited string, this injection attack provides every valid ID contained within `users.xml' to the user as a single row of output. As an extra safeguard, you should also test output before returning it to the user. Here is a simple example: mysql> SELECT @id = ExtractValue( -> LOAD_FILE('users.xml'), -> '//user[login/text()="" or 1=1 and password/text()="" or 1=1]/attribute::id' -> ); Query OK, 0 rows affected (0.00 sec) mysql> SELECT IF( -> INSTR(@id, ' ') = 0, -> @id, -> 'Unable to retrieve user ID') -> AS singleID; +----------------------------+ | singleID | +----------------------------+ | Unable to retrieve user ID | +----------------------------+ 1 row in set (0.00 sec) In general, the guidelines for returning data to users securely are the same as for accepting user input. These can be summed up as: * Always test outgoing data for type and permissible values. * Never permit unauthorized users to view error messages that might provide information about the application that could be used to exploit it.  File: manual.info, Node: bit-functions, Next: encryption-functions, Prev: xml-functions, Up: functions 12.12 Bit Functions =================== *Bitwise Functions* Name Description `BIT_COUNT()' Return the number of bits that are set `&' Bitwise AND `~' Invert bits `|' Bitwise OR `^' Bitwise XOR `<<' Left shift `>>' Right shift MySQL uses *Note `BIGINT': numeric-types. (64-bit) arithmetic for bit operations, so these operators have a maximum range of 64 bits. * `|' Bitwise OR: mysql> SELECT 29 | 15; -> 31 The result is an unsigned 64-bit integer. * `&' Bitwise AND: mysql> SELECT 29 & 15; -> 13 The result is an unsigned 64-bit integer. * `^' Bitwise XOR: mysql> SELECT 1 ^ 1; -> 0 mysql> SELECT 1 ^ 0; -> 1 mysql> SELECT 11 ^ 3; -> 8 The result is an unsigned 64-bit integer. * `<<' Shifts a longlong (*Note `BIGINT': numeric-types.) number to the left. mysql> SELECT 1 << 2; -> 4 The result is an unsigned 64-bit integer. The value is truncated to 64 bits. In particular, if the shift count is greater or equal to the width of an unsigned 64-bit number, the result is zero. * `>>' Shifts a longlong (*Note `BIGINT': numeric-types.) number to the right. mysql> SELECT 4 >> 2; -> 1 The result is an unsigned 64-bit integer. The value is truncated to 64 bits. In particular, if the shift count is greater or equal to the width of an unsigned 64-bit number, the result is zero. * `~' Invert all bits. mysql> SELECT 5 & ~1; -> 4 The result is an unsigned 64-bit integer. * `BIT_COUNT(N)' Returns the number of bits that are set in the argument N. mysql> SELECT BIT_COUNT(29), BIT_COUNT(b'101010'); -> 4, 3  File: manual.info, Node: encryption-functions, Next: information-functions, Prev: bit-functions, Up: functions 12.13 Encryption and Compression Functions ========================================== *Encryption Functions* Name Description `AES_DECRYPT()' Decrypt using AES `AES_ENCRYPT()' Encrypt using AES `COMPRESS()' Return result as a binary string `DECODE()' Decodes a string encrypted using ENCODE() `DES_DECRYPT()' Decrypt a string `DES_ENCRYPT()' Encrypt a string `ENCODE()' Encode a string `ENCRYPT()' Encrypt a string `MD5()' Calculate MD5 checksum `OLD_PASSWORD()' Return the value of the pre-4.1 implementation of PASSWORD `PASSWORD()' Calculate and return a password string `SHA1()', `SHA()' Calculate an SHA-1 160-bit checksum `UNCOMPRESS()' Uncompress a string compressed `UNCOMPRESSED_LENGTH()' Return the length of a string before compression Many encryption and compression functions return strings for which the result might contain arbitrary byte values. If you want to store these results, use a column with a *Note `VARBINARY': binary-varbinary. or *Note `BLOB': blob. binary string data type. This will avoid potential problems with trailing space removal or character set conversion that would change data values, such as may occur if you use a nonbinary string data type (*Note `CHAR': char, *Note `VARCHAR': char, *Note `TEXT': blob.). For functions such as `MD5()' or `SHA1()' that return a string of hex digits, the return value cannot be converted to uppercase or compared in case-insensitive fashion as is. You must convert the value to a nonbinary string. See the discussion of binary string conversion in *Note cast-functions::. If an application stores values from a function such as `MD5()' or `SHA1()' that returns a string of hex digits, more efficient storage and comparisons can be obtained by converting the hex representation to binary using `UNHEX()' and storing the result in a *Note `BINARY(N)': binary-varbinary. column. Each pair of hex digits requires one byte in binary form, so the value of N depends on the length of the hex string. N is 16 for an `MD5()' value and 20 for a `SHA1()' value. The size penalty for storing the hex string in a *Note `CHAR': char. column is at least two times, up to six times if the value is stored in a column that uses the `utf8' character set (where each character uses 3 bytes). Storing the string also results in slower comparisons because of the larger values and the need to take character set collation rules into account. Suppose that an application stores `MD5()' string values in a *Note `CHAR(32)': char. column: CREATE TABLE md5_tbl (md5_val CHAR(32), ...); INSERT INTO md5_tbl (md5_val, ...) VALUES(MD5('abcdef'), ...); To convert hex strings to more compact form, modify the application to use `UNHEX()' and *Note `BINARY(16)': binary-varbinary. instead as follows: CREATE TABLE md5_tbl (md5_val BINARY(16), ...); INSERT INTO md5_tbl (md5_val, ...) VALUES(UNHEX(MD5('abcdef')), ...); Applications should be prepared to handle the very rare case that a hashing function produces the same value for two different input values. One way to make collisions detectable is to make the hash column a primary key. *Note*: Exploits for the MD5 and SHA-1 algorithms have become known. You may wish to consider using one of the other encryption functions described in this section instead. *Caution*: Passwords or other sensitive values supplied as arguments to encryption functions are sent in plaintext to the MySQL server unless an SSL connection is used. Also, such values will appear in any MySQL logs to which they are written. To avoid these types of exposure, applications can encrypt sensitive values on the client side before sending them to the server. The same considerations apply to encryption keys. To avoid exposing these, applications can use stored procedures to encrypt and decrypt values on the server side. * `AES_DECRYPT(CRYPT_STR,KEY_STR)' This function decrypts data using the official AES (Advanced Encryption Standard) algorithm. For more information, see the description of `AES_ENCRYPT()'. * `AES_ENCRYPT(STR,KEY_STR)' `AES_ENCRYPT()' and `AES_DECRYPT()' enable encryption and decryption of data using the official AES (Advanced Encryption Standard) algorithm, previously known as `Rijndael.' Encoding with a 128-bit key length is used, but you can extend it up to 256 bits by modifying the source. We chose 128 bits because it is much faster and it is secure enough for most purposes. `AES_ENCRYPT()' encrypts a string and returns a binary string. `AES_DECRYPT()' decrypts the encrypted string and returns the original string. The input arguments may be any length. If either argument is `NULL', the result of this function is also `NULL'. Because AES is a block-level algorithm, padding is used to encode uneven length strings and so the result string length may be calculated using this formula: 16 * (trunc(STRING_LENGTH / 16) + 1) If `AES_DECRYPT()' detects invalid data or incorrect padding, it returns `NULL'. However, it is possible for `AES_DECRYPT()' to return a non-`NULL' value (possibly garbage) if the input data or the key is invalid. You can use the AES functions to store data in an encrypted form by modifying your queries: INSERT INTO t VALUES (1,AES_ENCRYPT('text','password')); `AES_ENCRYPT()' and `AES_DECRYPT()' can be considered the most cryptographically secure encryption functions currently available in MySQL. * `COMPRESS(STRING_TO_COMPRESS)' Compresses a string and returns the result as a binary string. This function requires MySQL to have been compiled with a compression library such as `zlib'. Otherwise, the return value is always `NULL'. The compressed string can be uncompressed with `UNCOMPRESS()'. mysql> SELECT LENGTH(COMPRESS(REPEAT('a',1000))); -> 21 mysql> SELECT LENGTH(COMPRESS('')); -> 0 mysql> SELECT LENGTH(COMPRESS('a')); -> 13 mysql> SELECT LENGTH(COMPRESS(REPEAT('a',16))); -> 15 The compressed string contents are stored the following way: * Empty strings are stored as empty strings. * Nonempty strings are stored as a four-byte length of the uncompressed string (low byte first), followed by the compressed string. If the string ends with space, an extra ``.'' character is added to avoid problems with endspace trimming should the result be stored in a *Note `CHAR': char. or *Note `VARCHAR': char. column. (However, use of nonbinary string data types such as *Note `CHAR': char. or *Note `VARCHAR': char. to store compressed strings is not recommended anyway because character set conversion may occur. Use a *Note `VARBINARY': binary-varbinary. or *Note `BLOB': blob. binary string column instead.) * `DECODE(CRYPT_STR,PASS_STR)' Decrypts the encrypted string CRYPT_STR using PASS_STR as the password. CRYPT_STR should be a string returned from `ENCODE()'. * `DES_DECRYPT(CRYPT_STR[,KEY_STR])' Decrypts a string encrypted with `DES_ENCRYPT()'. If an error occurs, this function returns `NULL'. This function works only if MySQL has been configured with SSL support. See *Note secure-connections::. If no KEY_STR argument is given, `DES_DECRYPT()' examines the first byte of the encrypted string to determine the DES key number that was used to encrypt the original string, and then reads the key from the DES key file to decrypt the message. For this to work, the user must have the `SUPER' privilege. The key file can be specified with the `--des-key-file' server option. If you pass this function a KEY_STR argument, that string is used as the key for decrypting the message. If the CRYPT_STR argument does not appear to be an encrypted string, MySQL returns the given CRYPT_STR. * `DES_ENCRYPT(STR[,{KEY_NUM|KEY_STR}])' Encrypts the string with the given key using the Triple-DES algorithm. This function works only if MySQL has been configured with SSL support. See *Note secure-connections::. The encryption key to use is chosen based on the second argument to `DES_ENCRYPT()', if one was given. With no argument, the first key from the DES key file is used. With a KEY_NUM argument, the given key number (0 to 9) from the DES key file is used. With a KEY_STR argument, the given key string is used to encrypt STR. The key file can be specified with the `--des-key-file' server option. The return string is a binary string where the first character is `CHAR(128 | KEY_NUM)'. If an error occurs, `DES_ENCRYPT()' returns `NULL'. The 128 is added to make it easier to recognize an encrypted key. If you use a string key, KEY_NUM is 127. The string length for the result is given by this formula: NEW_LEN = ORIG_LEN + (8 - (ORIG_LEN % 8)) + 1 Each line in the DES key file has the following format: KEY_NUM DES_KEY_STR Each KEY_NUM value must be a number in the range from `0' to `9'. Lines in the file may be in any order. DES_KEY_STR is the string that is used to encrypt the message. There should be at least one space between the number and the key. The first key is the default key that is used if you do not specify any key argument to `DES_ENCRYPT()'. You can tell MySQL to read new key values from the key file with the *Note `FLUSH DES_KEY_FILE': flush. statement. This requires the `RELOAD' privilege. One benefit of having a set of default keys is that it gives applications a way to check for the existence of encrypted column values, without giving the end user the right to decrypt those values. mysql> SELECT customer_address FROM customer_table > WHERE crypted_credit_card = DES_ENCRYPT('credit_card_number'); * `ENCODE(STR,PASS_STR)' Encrypt STR using PASS_STR as the password. To decrypt the result, use `DECODE()'. The result is a binary string of the same length as STR. The strength of the encryption is based on how good the random generator is. It should suffice for short strings. * `ENCRYPT(STR[,SALT])' Encrypts STR using the Unix `crypt()' system call and returns a binary string. The SALT argument must be a string with at least two characters or the result will be `NULL'. If no SALT argument is given, a random value is used. mysql> SELECT ENCRYPT('hello'); -> 'VxuFAJXVARROc' `ENCRYPT()' ignores all but the first eight characters of STR, at least on some systems. This behavior is determined by the implementation of the underlying `crypt()' system call. The use of `ENCRYPT()' with the `ucs2' multi-byte character set is not recommended because the system call expects a string terminated by a zero byte. If `crypt()' is not available on your system (as is the case with Windows), `ENCRYPT()' always returns `NULL'. * `MD5(STR)' Calculates an MD5 128-bit checksum for the string. The value is returned as a binary string of 32 hex digits, or `NULL' if the argument was `NULL'. The return value can, for example, be used as a hash key. See the notes at the beginning of this section about storing hash values efficiently. mysql> SELECT MD5('testing'); -> 'ae2b1fca515949e5d54fb22b8ed95575' This is the `RSA Data Security, Inc. MD5 Message-Digest Algorithm.' See the note regarding the MD5 algorithm at the beginning this section. * `OLD_PASSWORD(STR)' `OLD_PASSWORD()' was added when the implementation of `PASSWORD()' was changed in MySQL 4.1 to improve security. `OLD_PASSWORD()' returns the value of the pre-4.1 implementation of `PASSWORD()' as a binary string, and is intended to permit you to reset passwords for any pre-4.1 clients that need to connect to your version 5.1 MySQL server without locking them out. See *Note password-hashing::. * `PASSWORD(STR)' Calculates and returns a password string from the plaintext password STR and returns a binary string, or `NULL' if the argument was `NULL'. This is the function that is used for encrypting MySQL passwords for storage in the `Password' column of the `user' grant table. mysql> SELECT PASSWORD('badpwd'); -> '*AAB3E285149C0135D51A520E1940DD3263DC008C' `PASSWORD()' encryption is one-way (not reversible). `PASSWORD()' does not perform password encryption in the same way that Unix passwords are encrypted. See `ENCRYPT()'. *Note*: The `PASSWORD()' function is used by the authentication system in MySQL Server; you should _not_ use it in your own applications. For that purpose, consider `MD5()' or `SHA1()' instead. Also see section 2 (Challenge-Response Authentication Mechanism (CRAM)), for more information about handling passwords and authentication securely in your applications. *Important*: Statements that invoke `PASSWORD()' may be recorded in server logs or in a history file such as `~/.mysql_history', which means that plaintext passwords may be read by anyone having read access to that information. See *Note password-security::. * `SHA1(STR)', `SHA(STR)' Calculates an SHA-1 160-bit checksum for the string, as described in RFC 3174 (Secure Hash Algorithm). The value is returned as a binary string of 40 hex digits, or `NULL' if the argument was `NULL'. One of the possible uses for this function is as a hash key. See the notes at the beginning of this section about storing hash values efficiently. You can also use `SHA1()' as a cryptographic function for storing passwords. `SHA()' is synonymous with `SHA1()'. mysql> SELECT SHA1('abc'); -> 'a9993e364706816aba3e25717850c26c9cd0d89d' `SHA1()' can be considered a cryptographically more secure equivalent of `MD5()'. However, see the note regarding the MD5 and SHA-1 algorithms at the beginning this section. * `UNCOMPRESS(STRING_TO_UNCOMPRESS)' Uncompresses a string compressed by the `COMPRESS()' function. If the argument is not a compressed value, the result is `NULL'. This function requires MySQL to have been compiled with a compression library such as `zlib'. Otherwise, the return value is always `NULL'. mysql> SELECT UNCOMPRESS(COMPRESS('any string')); -> 'any string' mysql> SELECT UNCOMPRESS('any string'); -> NULL * `UNCOMPRESSED_LENGTH(COMPRESSED_STRING)' Returns the length that the compressed string had before being compressed. mysql> SELECT UNCOMPRESSED_LENGTH(COMPRESS(REPEAT('a',30))); -> 30  File: manual.info, Node: information-functions, Next: miscellaneous-functions, Prev: encryption-functions, Up: functions 12.14 Information Functions =========================== *Information Functions* Name Description `BENCHMARK()' Repeatedly execute an expression `CHARSET()' Return the character set of the argument `COERCIBILITY()' Return the collation coercibility value of the string argument `COLLATION()' Return the collation of the string argument `CONNECTION_ID()' Return the connection ID (thread ID) for the connection `CURRENT_USER()', The authenticated user name and host name `CURRENT_USER' `DATABASE()' Return the default (current) database name `FOUND_ROWS()' For a SELECT with a LIMIT clause, the number of rows that would be returned were there no LIMIT clause `LAST_INSERT_ID()' Value of the AUTOINCREMENT column for the last INSERT `ROW_COUNT()' The number of rows updated `SCHEMA()' A synonym for DATABASE() `SESSION_USER()' Synonym for USER() `SYSTEM_USER()' Synonym for USER() `USER()' The user name and host name provided by the client `VERSION()' Returns a string that indicates the MySQL server version * `BENCHMARK(COUNT,EXPR)' The `BENCHMARK()' function executes the expression EXPR repeatedly COUNT times. It may be used to time how quickly MySQL processes the expression. The result value is always `0'. The intended use is from within the *Note `mysql': mysql. client, which reports query execution times: mysql> SELECT BENCHMARK(1000000,ENCODE('hello','goodbye')); +----------------------------------------------+ | BENCHMARK(1000000,ENCODE('hello','goodbye')) | +----------------------------------------------+ | 0 | +----------------------------------------------+ 1 row in set (4.74 sec) The time reported is elapsed time on the client end, not CPU time on the server end. It is advisable to execute `BENCHMARK()' several times, and to interpret the result with regard to how heavily loaded the server machine is. `BENCHMARK()' is intended for measuring the runtime performance of scalar expressions, which has some significant implications for the way that you use it and interpret the results: * Only scalar expressions can be used. Although the expression can be a subquery, it must return a single column and at most a single row. For example, `BENCHMARK(10, (SELECT * FROM t))' will fail if the table `t' has more than one column or more than one row. * Executing a `SELECT EXPR' statement N times differs from executing `SELECT BENCHMARK(N, EXPR)' in terms of the amount of overhead involved. The two have very different execution profiles and you should not expect them to take the same amount of time. The former involves the parser, optimizer, table locking, and runtime evaluation N times each. The latter involves only runtime evaluation N times, and all the other components just once. Memory structures already allocated are reused, and runtime optimizations such as local caching of results already evaluated for aggregate functions can alter the results. Use of `BENCHMARK()' thus measures performance of the runtime component by giving more weight to that component and removing the `noise' introduced by the network, parser, optimizer, and so forth. * `CHARSET(STR)' Returns the character set of the string argument. mysql> SELECT CHARSET('abc'); -> 'latin1' mysql> SELECT CHARSET(CONVERT('abc' USING utf8)); -> 'utf8' mysql> SELECT CHARSET(USER()); -> 'utf8' * `COERCIBILITY(STR)' Returns the collation coercibility value of the string argument. mysql> SELECT COERCIBILITY('abc' COLLATE latin1_swedish_ci); -> 0 mysql> SELECT COERCIBILITY(USER()); -> 3 mysql> SELECT COERCIBILITY('abc'); -> 4 The return values have the meanings shown in the following table. Lower values have higher precedence. CoercibilityMeaning Example `0' Explicit Value with `COLLATE' clause collation `1' No Concatenation of strings with different collation collations `2' Implicit Column value, stored routine parameter or collation local variable `3' System `USER()' return value constant `4' Coercible Literal string `5' Ignorable `NULL' or an expression derived from `NULL' * `COLLATION(STR)' Returns the collation of the string argument. mysql> SELECT COLLATION('abc'); -> 'latin1_swedish_ci' mysql> SELECT COLLATION(_utf8'abc'); -> 'utf8_general_ci' * `CONNECTION_ID()' Returns the connection ID (thread ID) for the connection. Every connection has an ID that is unique among the set of currently connected clients. mysql> SELECT CONNECTION_ID(); -> 23786 * `CURRENT_USER', `CURRENT_USER()' Returns the user name and host name combination for the MySQL account that the server used to authenticate the current client. This account determines your access privileges. The return value is a string in the `utf8' character set. The value of `CURRENT_USER()' can differ from the value of `USER()'. mysql> SELECT USER(); -> 'davida@localhost' mysql> SELECT * FROM mysql.user; ERROR 1044: Access denied for user ''@'localhost' to database 'mysql' mysql> SELECT CURRENT_USER(); -> '@localhost' The example illustrates that although the client specified a user name of `davida' (as indicated by the value of the `USER()' function), the server authenticated the client using an anonymous user account (as seen by the empty user name part of the `CURRENT_USER()' value). One way this might occur is that there is no account listed in the grant tables for `davida'. Within a stored program or view, `CURRENT_USER()' returns the account for the user who defined the object (as given by its `DEFINER' value). For stored procedures and functions and views defined with the `SQL SECURITY INVOKER' characteristic, `CURRENT_USER()' returns the object's invoker. The following statements support use of the `CURRENT_USER()' function to take the place of the name of (and, possibly, a host for) an affected user or a definer; in such cases, `CURRENT_USER()' is expanded where and as needed: * *Note `DROP USER': drop-user. * *Note `RENAME USER': rename-user. * *Note `GRANT': grant. * *Note `REVOKE': revoke. * *Note `CREATE FUNCTION': create-function. * *Note `CREATE PROCEDURE': create-procedure. * *Note `CREATE TRIGGER': create-trigger. * *Note `CREATE EVENT': create-event. * *Note `CREATE VIEW': create-view. * *Note `ALTER EVENT': alter-event. * *Note `ALTER VIEW': alter-view. * *Note `SET PASSWORD': set-password. For information about the implications that this expansion of `CURRENT_USER()' has for replication in different releases of MySQL 5.1, see *Note replication-features-current-user::. * `DATABASE()' Returns the default (current) database name as a string in the `utf8' character set. If there is no default database, `DATABASE()' returns `NULL'. Within a stored routine, the default database is the database that the routine is associated with, which is not necessarily the same as the database that is the default in the calling context. mysql> SELECT DATABASE(); -> 'test' If there is no default database, `DATABASE()' returns `NULL'. * `FOUND_ROWS()' A *Note `SELECT': select. statement may include a `LIMIT' clause to restrict the number of rows the server returns to the client. In some cases, it is desirable to know how many rows the statement would have returned without the `LIMIT', but without running the statement again. To obtain this row count, include a `SQL_CALC_FOUND_ROWS' option in the *Note `SELECT': select. statement, and then invoke `FOUND_ROWS()' afterward: mysql> SELECT SQL_CALC_FOUND_ROWS * FROM TBL_NAME -> WHERE id > 100 LIMIT 10; mysql> SELECT FOUND_ROWS(); The second *Note `SELECT': select. returns a number indicating how many rows the first *Note `SELECT': select. would have returned had it been written without the `LIMIT' clause. In the absence of the `SQL_CALC_FOUND_ROWS' option in the most recent successful *Note `SELECT': select. statement, `FOUND_ROWS()' returns the number of rows in the result set returned by that statement. If the statement includes a `LIMIT' clause, `FOUND_ROWS()' returns the number of rows up to the limit. For example, `FOUND_ROWS()' returns 10 or 60, respectively, if the statement includes `LIMIT 10' or `LIMIT 50, 10'. The row count available through `FOUND_ROWS()' is transient and not intended to be available past the statement following the `SELECT SQL_CALC_FOUND_ROWS' statement. If you need to refer to the value later, save it: mysql> SELECT SQL_CALC_FOUND_ROWS * FROM ... ; mysql> SET @rows = FOUND_ROWS(); If you are using `SELECT SQL_CALC_FOUND_ROWS', MySQL must calculate how many rows are in the full result set. However, this is faster than running the query again without `LIMIT', because the result set need not be sent to the client. `SQL_CALC_FOUND_ROWS' and `FOUND_ROWS()' can be useful in situations when you want to restrict the number of rows that a query returns, but also determine the number of rows in the full result set without running the query again. An example is a Web script that presents a paged display containing links to the pages that show other sections of a search result. Using `FOUND_ROWS()' enables you to determine how many other pages are needed for the rest of the result. The use of `SQL_CALC_FOUND_ROWS' and `FOUND_ROWS()' is more complex for *Note `UNION': union. statements than for simple *Note `SELECT': select. statements, because `LIMIT' may occur at multiple places in a *Note `UNION': union. It may be applied to individual *Note `SELECT': select. statements in the *Note `UNION': union, or global to the *Note `UNION': union. result as a whole. The intent of `SQL_CALC_FOUND_ROWS' for *Note `UNION': union. is that it should return the row count that would be returned without a global `LIMIT'. The conditions for use of `SQL_CALC_FOUND_ROWS' with *Note `UNION': union. are: * The `SQL_CALC_FOUND_ROWS' keyword must appear in the first *Note `SELECT': select. of the *Note `UNION': union. * The value of `FOUND_ROWS()' is exact only if *Note `UNION ALL': union. is used. If *Note `UNION': union. without `ALL' is used, duplicate removal occurs and the value of `FOUND_ROWS()' is only approximate. * If no `LIMIT' is present in the *Note `UNION': union, `SQL_CALC_FOUND_ROWS' is ignored and returns the number of rows in the temporary table that is created to process the *Note `UNION': union. Beyond the cases described here, the behavior of `FOUND_ROWS()' is undefined (for example, its value following a *Note `SELECT': select. statement that fails with an error). *Important*: `FOUND_ROWS()' is not replicated reliably using statement-based replication. Starting with MySQL 5.1.23, this function is automatically replicated using row-based replication. * `LAST_INSERT_ID()', `LAST_INSERT_ID(EXPR)' For MySQL 5.1.12 and later, `LAST_INSERT_ID()' (with no argument) returns the _first_ automatically generated value _successfully_ inserted for an `AUTO_INCREMENT' column as a result of the most recently executed *Note `INSERT': insert. statement. The value of `LAST_INSERT_ID()' remains unchanged if no rows are successfully inserted. For example, after inserting a row that generates an `AUTO_INCREMENT' value, you can get the value like this: mysql> SELECT LAST_INSERT_ID(); -> 195 In MySQL 5.1.11 and earlier, `LAST_INSERT_ID()' (with no argument) returns the _first_ automatically generated value if any rows were successfully inserted or updated. This means that the returned value could be a value that was not successfully inserted into the table. If no rows were successfully inserted, `LAST_INSERT_ID()' returns 0. The value of `LAST_INSERT_ID()' will be consistent across all MySQL versions if all rows in the *Note `INSERT': insert. or *Note `UPDATE': update. statement were successful. if a table contains an `AUTO_INCREMENT' column and *Note `INSERT ... ON DUPLICATE KEY UPDATE': insert-on-duplicate. updates (rather than inserts) a row, the value of `LAST_INSERT_ID()' is not meaningful prior to MySQL 5.1.12. For a workaround, see *Note insert-on-duplicate::. The currently executing statement does not affect the value of `LAST_INSERT_ID()'. Suppose that you generate an `AUTO_INCREMENT' value with one statement, and then refer to `LAST_INSERT_ID()' in a multiple-row *Note `INSERT': insert. statement that inserts rows into a table with its own `AUTO_INCREMENT' column. The value of `LAST_INSERT_ID()' will remain stable in the second statement; its value for the second and later rows is not affected by the earlier row insertions. (However, if you mix references to `LAST_INSERT_ID()' and `LAST_INSERT_ID(EXPR)', the effect is undefined.) If the previous statement returned an error, the value of `LAST_INSERT_ID()' is undefined. For transactional tables, if the statement is rolled back due to an error, the value of `LAST_INSERT_ID()' is left undefined. For manual *Note `ROLLBACK': commit, the value of `LAST_INSERT_ID()' is not restored to that before the transaction; it remains as it was at the point of the *Note `ROLLBACK': commit. Within the body of a stored routine (procedure or function) or a trigger, the value of `LAST_INSERT_ID()' changes the same way as for statements executed outside the body of these kinds of objects. The effect of a stored routine or trigger upon the value of `LAST_INSERT_ID()' that is seen by following statements depends on the kind of routine: * If a stored procedure executes statements that change the value of `LAST_INSERT_ID()', the changed value is seen by statements that follow the procedure call. * For stored functions and triggers that change the value, the value is restored when the function or trigger ends, so following statements will not see a changed value. The ID that was generated is maintained in the server on a _per-connection basis_. This means that the value returned by the function to a given client is the first `AUTO_INCREMENT' value generated for most recent statement affecting an `AUTO_INCREMENT' column _by that client_. This value cannot be affected by other clients, even if they generate `AUTO_INCREMENT' values of their own. This behavior ensures that each client can retrieve its own ID without concern for the activity of other clients, and without the need for locks or transactions. The value of `LAST_INSERT_ID()' is not changed if you set the `AUTO_INCREMENT' column of a row to a non-`magic' value (that is, a value that is not `NULL' and not `0'). *Important*: If you insert multiple rows using a single *Note `INSERT': insert. statement, `LAST_INSERT_ID()' returns the value generated for the _first_ inserted row _only_. The reason for this is to make it possible to reproduce easily the same *Note `INSERT': insert. statement against some other server. For example: mysql> USE test; Database changed mysql> CREATE TABLE t ( -> id INT AUTO_INCREMENT NOT NULL PRIMARY KEY, -> name VARCHAR(10) NOT NULL -> ); Query OK, 0 rows affected (0.09 sec) mysql> INSERT INTO t VALUES (NULL, 'Bob'); Query OK, 1 row affected (0.01 sec) mysql> SELECT * FROM t; +----+------+ | id | name | +----+------+ | 1 | Bob | +----+------+ 1 row in set (0.01 sec) mysql> SELECT LAST_INSERT_ID(); +------------------+ | LAST_INSERT_ID() | +------------------+ | 1 | +------------------+ 1 row in set (0.00 sec) mysql> INSERT INTO t VALUES -> (NULL, 'Mary'), (NULL, 'Jane'), (NULL, 'Lisa'); Query OK, 3 rows affected (0.00 sec) Records: 3 Duplicates: 0 Warnings: 0 mysql> SELECT * FROM t; +----+------+ | id | name | +----+------+ | 1 | Bob | | 2 | Mary | | 3 | Jane | | 4 | Lisa | +----+------+ 4 rows in set (0.01 sec) mysql> SELECT LAST_INSERT_ID(); +------------------+ | LAST_INSERT_ID() | +------------------+ | 2 | +------------------+ 1 row in set (0.00 sec) Although the second *Note `INSERT': insert. statement inserted three new rows into `t', the ID generated for the first of these rows was `2', and it is this value that is returned by `LAST_INSERT_ID()' for the following *Note `SELECT': select. statement. If you use *Note `INSERT IGNORE': insert. and the row is ignored, the `AUTO_INCREMENT' counter is not incremented and `LAST_INSERT_ID()' returns `0', which reflects that no row was inserted. If EXPR is given as an argument to `LAST_INSERT_ID()', the value of the argument is returned by the function and is remembered as the next value to be returned by `LAST_INSERT_ID()'. This can be used to simulate sequences: 1. Create a table to hold the sequence counter and initialize it: mysql> CREATE TABLE sequence (id INT NOT NULL); mysql> INSERT INTO sequence VALUES (0); 2. Use the table to generate sequence numbers like this: mysql> UPDATE sequence SET id=LAST_INSERT_ID(id+1); mysql> SELECT LAST_INSERT_ID(); The *Note `UPDATE': update. statement increments the sequence counter and causes the next call to `LAST_INSERT_ID()' to return the updated value. The *Note `SELECT': select. statement retrieves that value. The *Note `mysql_insert_id()': mysql-insert-id. C API function can also be used to get the value. See *Note mysql-insert-id::. You can generate sequences without calling `LAST_INSERT_ID()', but the utility of using the function this way is that the ID value is maintained in the server as the last automatically generated value. It is multi-user safe because multiple clients can issue the *Note `UPDATE': update. statement and get their own sequence value with the *Note `SELECT': select. statement (or *Note `mysql_insert_id()': mysql-insert-id.), without affecting or being affected by other clients that generate their own sequence values. Note that *Note `mysql_insert_id()': mysql-insert-id. is only updated after *Note `INSERT': insert. and *Note `UPDATE': update. statements, so you cannot use the C API function to retrieve the value for `LAST_INSERT_ID(EXPR)' after executing other SQL statements like *Note `SELECT': select. or *Note `SET': set-option. * `ROW_COUNT()' `ROW_COUNT()' returns the number of rows changed, deleted, or inserted by the last statement if it was an *Note `UPDATE': update, *Note `DELETE': delete, or *Note `INSERT': insert. For other statements, the value may not be meaningful. For *Note `UPDATE': update. statements, the affected-rows value by default is the number of rows actually changed. If you specify the `CLIENT_FOUND_ROWS' flag to *Note `mysql_real_connect()': mysql-real-connect. when connecting to *Note `mysqld': mysqld, the affected-rows value is the number of rows `found'; that is, matched by the `WHERE' clause. For *Note `REPLACE': replace. statements, the affected-rows value is 2 if the new row replaced an old row, because in this case, one row was inserted after the duplicate was deleted. For *Note `INSERT ... ON DUPLICATE KEY UPDATE': insert-on-duplicate. statements, the affected-rows value is 1 if the row is inserted as a new row and 2 if an existing row is updated. The `ROW_COUNT()' value is the same as the value from the *Note `mysql_affected_rows()': mysql-affected-rows. C API function and the row count that the *Note `mysql': mysql. client displays following statement execution. mysql> INSERT INTO t VALUES(1),(2),(3); Query OK, 3 rows affected (0.00 sec) Records: 3 Duplicates: 0 Warnings: 0 mysql> SELECT ROW_COUNT(); +-------------+ | ROW_COUNT() | +-------------+ | 3 | +-------------+ 1 row in set (0.00 sec) mysql> DELETE FROM t WHERE i IN(1,2); Query OK, 2 rows affected (0.00 sec) mysql> SELECT ROW_COUNT(); +-------------+ | ROW_COUNT() | +-------------+ | 2 | +-------------+ 1 row in set (0.00 sec) *Important*: `ROW_COUNT()' is not replicated reliably using statement-based replication. Beginning with MySQL 5.1.23, this function is automatically replicated using row-based replication. (Bug#30244) * `SCHEMA()' This function is a synonym for `DATABASE()'. * `SESSION_USER()' `SESSION_USER()' is a synonym for `USER()'. * `SYSTEM_USER()' `SYSTEM_USER()' is a synonym for `USER()'. * `USER()' Returns the current MySQL user name and host name as a string in the `utf8' character set. mysql> SELECT USER(); -> 'davida@localhost' The value indicates the user name you specified when connecting to the server, and the client host from which you connected. The value can be different from that of `CURRENT_USER()'. You can extract only the user name part like this: mysql> SELECT SUBSTRING_INDEX(USER(),'@',1); -> 'davida' * `VERSION()' Returns a string that indicates the MySQL server version. The string uses the `utf8' character set. The value might have a suffix in addition to the version number. See the description of the `version' system variable in *Note server-system-variables::. This function is unsafe for statement-based replication. Beginning with MySQL 5.1.42, a warning is logged if you use this function when `binlog_format' is set to `STATEMENT'. (Bug#47995) mysql> SELECT VERSION(); -> '5.1.59-standard'  File: manual.info, Node: miscellaneous-functions, Next: group-by-functions-and-modifiers, Prev: information-functions, Up: functions 12.15 Miscellaneous Functions ============================= *Miscellaneous Functions* Name Description `DEFAULT()' Return the default value for a table column `GET_LOCK()' Get a named lock `INET_ATON()' Return the numeric value of an IP address `INET_NTOA()' Return the IP address from a numeric value `IS_FREE_LOCK()' Checks whether the named lock is free `IS_USED_LOCK()' Checks whether the named lock is in use. Return connection identifier if true. `MASTER_POS_WAIT()' Block until the slave has read and applied all updates up to the specified position `NAME_CONST()' Causes the column to have the given name `RAND()' Return a random floating-point value `RELEASE_LOCK()' Releases the named lock `SLEEP()' Sleep for a number of seconds `UUID_SHORT()' Return an integer-valued universal identifier `UUID()' Return a Universal Unique Identifier (UUID) `VALUES()' Defines the values to be used during an INSERT * `DEFAULT(COL_NAME)' Returns the default value for a table column. An error results if the column has no default value. mysql> UPDATE t SET i = DEFAULT(i)+1 WHERE id < 100; * `FORMAT(X,D)' Formats the number X to a format like `'#,###,###.##'', rounded to D decimal places, and returns the result as a string. For details, see *Note string-functions::. * `GET_LOCK(STR,TIMEOUT)' Tries to obtain a lock with a name given by the string STR, using a timeout of TIMEOUT seconds. Returns `1' if the lock was obtained successfully, `0' if the attempt timed out (for example, because another client has previously locked the name), or `NULL' if an error occurred (such as running out of memory or the thread was killed with *Note `mysqladmin kill': mysqladmin.). If you have a lock obtained with `GET_LOCK()', it is released when you execute `RELEASE_LOCK()', execute a new `GET_LOCK()', or your connection terminates (either normally or abnormally). Locks obtained with `GET_LOCK()' do not interact with transactions. That is, committing a transaction does not release any such locks obtained during the transaction. This function can be used to implement application locks or to simulate record locks. Names are locked on a server-wide basis. If a name has been locked by one client, `GET_LOCK()' blocks any request by another client for a lock with the same name. This enables clients that agree on a given lock name to use the name to perform cooperative advisory locking. But be aware that it also enables a client that is not among the set of cooperating clients to lock a name, either inadvertently or deliberately, and thus prevent any of the cooperating clients from locking that name. One way to reduce the likelihood of this is to use lock names that are database-specific or application-specific. For example, use lock names of the form DB_NAME.STR or APP_NAME.STR. mysql> SELECT GET_LOCK('lock1',10); -> 1 mysql> SELECT IS_FREE_LOCK('lock2'); -> 1 mysql> SELECT GET_LOCK('lock2',10); -> 1 mysql> SELECT RELEASE_LOCK('lock2'); -> 1 mysql> SELECT RELEASE_LOCK('lock1'); -> NULL The second `RELEASE_LOCK()' call returns `NULL' because the lock `'lock1'' was automatically released by the second `GET_LOCK()' call. If multiple clients are waiting for a lock, the order in which they will acquire it is undefined and depends on factors such as the thread library in use. In particular, applications should not assume that clients will acquire the lock in the same order that they issued the lock requests. *Note*: If a client attempts to acquire a lock that is already held by another client, it blocks according to the TIMEOUT argument. If the blocked client terminates, its thread does not die until the lock request times out. This is a known bug (fixed in MySQL 5.5). This function is unsafe for statement-based replication. Beginning with MySQL 5.1.42, a warning is logged if you use this function when `binlog_format' is set to `STATEMENT'. (Bug#47995) * `INET_ATON(EXPR)' Given the dotted-quad representation of an IPv4 network address as a string, returns an integer that represents the numeric value of the address in network byte order (big endian). `INET_ATON()' returns `NULL' if it does not understand its argument. mysql> SELECT INET_ATON('10.0.5.9'); -> 167773449 For this example, the return value is calculated as 10x256^3 + 0x256^2 + 5x256 + 9. `INET_ATON()' may or may not return a non-`NULL' result for short-form IP addresses (such as `'127.1'' as a representation of `'127.0.0.1''). Because of this, `INET_ATON()'a should not be used for such addresses. *Note*: To store values generated by `INET_ATON()', use an `INT UNSIGNED' column rather than *Note `INT': numeric-types, which is signed. If you use a signed column, values corresponding to IP addresses for which the first octet is greater than 127 cannot be stored correctly. See *Note out-of-range-and-overflow::. * `INET_NTOA(EXPR)' Given a numeric IPv4 network address in network byte order, returns the dotted-quad representation of the address as a binary string. `INET_NTOA()' returns `NULL' if it does not understand its argument. mysql> SELECT INET_NTOA(167773449); -> '10.0.5.9' * `IS_FREE_LOCK(STR)' Checks whether the lock named STR is free to use (that is, not locked). Returns `1' if the lock is free (no one is using the lock), `0' if the lock is in use, and `NULL' if an error occurs (such as an incorrect argument). This function is unsafe for statement-based replication. Beginning with MySQL 5.1.42, a warning is logged if you use this function when `binlog_format' is set to `STATEMENT'. (Bug#47995) * `IS_USED_LOCK(STR)' Checks whether the lock named STR is in use (that is, locked). If so, it returns the connection identifier of the client that holds the lock. Otherwise, it returns `NULL'. This function is unsafe for statement-based replication. Beginning with MySQL 5.1.42, a warning is logged if you use this function when `binlog_format' is set to `STATEMENT'. (Bug#47995) * `MASTER_POS_WAIT(LOG_NAME,LOG_POS[,TIMEOUT])' This function is useful for control of master/slave synchronization. It blocks until the slave has read and applied all updates up to the specified position in the master log. The return value is the number of log events the slave had to wait for to advance to the specified position. The function returns `NULL' if the slave SQL thread is not started, the slave's master information is not initialized, the arguments are incorrect, or an error occurs. It returns `-1' if the timeout has been exceeded. If the slave SQL thread stops while `MASTER_POS_WAIT()' is waiting, the function returns `NULL'. If the slave is past the specified position, the function returns immediately. If a TIMEOUT value is specified, `MASTER_POS_WAIT()' stops waiting when TIMEOUT seconds have elapsed. TIMEOUT must be greater than 0; a zero or negative TIMEOUT means no timeout. This function is unsafe for statement-based replication. Beginning with MySQL 5.1.42, a warning is logged if you use this function when `binlog_format' is set to `STATEMENT'. (Bug#47995) * `NAME_CONST(NAME,VALUE)' Returns the given value. When used to produce a result set column, `NAME_CONST()' causes the column to have the given name. The arguments should be constants. mysql> SELECT NAME_CONST('myname', 14); +--------+ | myname | +--------+ | 14 | +--------+ This function is for internal use only. The server uses it when writing statements from stored programs that contain references to local program variables, as described in *Note stored-programs-logging::, You might see this function in the output from *Note `mysqlbinlog': mysqlbinlog. * `RELEASE_LOCK(STR)' Releases the lock named by the string STR that was obtained with `GET_LOCK()'. Returns `1' if the lock was released, `0' if the lock was not established by this thread (in which case the lock is not released), and `NULL' if the named lock did not exist. The lock does not exist if it was never obtained by a call to `GET_LOCK()' or if it has previously been released. The *Note `DO': do. statement is convenient to use with `RELEASE_LOCK()'. See *Note do::. This function is unsafe for statement-based replication. Beginning with MySQL 5.1.42, a warning is logged if you use this function when `binlog_format' is set to `STATEMENT'. (Bug#47995) * `SLEEP(DURATION)' Sleeps (pauses) for the number of seconds given by the DURATION argument, then returns 0. If `SLEEP()' is interrupted, it returns 1. The duration may have a fractional part given in microseconds. This function is unsafe for statement-based replication. Beginning with MySQL 5.1.42, a warning is logged if you use this function when `binlog_format' is set to `STATEMENT'. (Bug#47995) * `UUID()' Returns a Universal Unique Identifier (UUID) generated according to `DCE 1.1: Remote Procedure Call' (Appendix A) CAE (Common Applications Environment) Specifications published by The Open Group in October 1997 (Document Number C706, `http://www.opengroup.org/public/pubs/catalog/c706.htm'). A UUID is designed as a number that is globally unique in space and time. Two calls to `UUID()' are expected to generate two different values, even if these calls are performed on two separate computers that are not connected to each other. A UUID is a 128-bit number represented by a `utf8' string of five hexadecimal numbers in `aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee' format: * The first three numbers are generated from a timestamp. * The fourth number preserves temporal uniqueness in case the timestamp value loses monotonicity (for example, due to daylight saving time). * The fifth number is an IEEE 802 node number that provides spatial uniqueness. A random number is substituted if the latter is not available (for example, because the host computer has no Ethernet card, or we do not know how to find the hardware address of an interface on your operating system). In this case, spatial uniqueness cannot be guaranteed. Nevertheless, a collision should have _very_ low probability. Currently, the MAC address of an interface is taken into account only on FreeBSD and Linux. On other operating systems, MySQL uses a randomly generated 48-bit number. mysql> SELECT UUID(); -> '6ccd780c-baba-1026-9564-0040f4311e29' *Warning*: Although `UUID()' values are intended to be unique, they are not necessarily unguessable or unpredictable. If unpredictability is required, UUID values should be generated some other way. *Note*: `UUID()' does not work with statement-based replication. * `UUID_SHORT()' Returns a `short' universal identifier as a 64-bit unsigned integer (rather than a string-form 128-bit identifier as returned by the `UUID()' function). The value of `UUID_SHORT()' is guaranteed to be unique if the following conditions hold: * The `server_id' of the current host is unique among your set of master and slave servers * `server_id' is between 0 and 255 * You do not set back your system time for your server between *Note `mysqld': mysqld. restarts * You do not invoke `UUID_SHORT()' on average more than 16 million times per second between *Note `mysqld': mysqld. restarts The `UUID_SHORT()' return value is constructed this way: (server_id & 255) << 56 + (server_startup_time_in_seconds << 24) + incremented_variable++; mysql> SELECT UUID_SHORT(); -> 92395783831158784 Note that `UUID_SHORT()' does not work with statement-based replication. This function was added in MySQL 5.1.20. * `VALUES(COL_NAME)' In an *Note `INSERT ... ON DUPLICATE KEY UPDATE': insert-on-duplicate. statement, you can use the `VALUES(COL_NAME)' function in the *Note `UPDATE': update. clause to refer to column values from the *Note `INSERT': insert. portion of the statement. In other words, `VALUES(COL_NAME)' in the *Note `UPDATE': update. clause refers to the value of COL_NAME that would be inserted, had no duplicate-key conflict occurred. This function is especially useful in multiple-row inserts. The `VALUES()' function is meaningful only in the `ON DUPLICATE KEY UPDATE' clause of *Note `INSERT': insert. statements and returns `NULL' otherwise. See *Note insert-on-duplicate::. mysql> INSERT INTO table (a,b,c) VALUES (1,2,3),(4,5,6) -> ON DUPLICATE KEY UPDATE c=VALUES(a)+VALUES(b);  File: manual.info, Node: group-by-functions-and-modifiers, Next: spatial-extensions, Prev: miscellaneous-functions, Up: functions 12.16 Functions and Modifiers for Use with `GROUP BY' Clauses ============================================================= * Menu: * group-by-functions:: `GROUP BY' (Aggregate) Functions * group-by-modifiers:: `GROUP BY' Modifiers * group-by-hidden-columns:: `GROUP BY' and `HAVING' with Hidden Columns  File: manual.info, Node: group-by-functions, Next: group-by-modifiers, Prev: group-by-functions-and-modifiers, Up: group-by-functions-and-modifiers 12.16.1 `GROUP BY' (Aggregate) Functions ---------------------------------------- *Aggregate (`GROUP BY') Functions* Name Description `AVG()' Return the average value of the argument `BIT_AND()' Return bitwise and `BIT_OR()' Return bitwise or `BIT_XOR()' Return bitwise xor `COUNT(DISTINCT)' Return the count of a number of different values `COUNT()' Return a count of the number of rows returned `GROUP_CONCAT()' Return a concatenated string `MAX()' Return the maximum value `MIN()' Return the minimum value `STD()' Return the population standard deviation `STDDEV_POP()' Return the population standard deviation `STDDEV_SAMP()' Return the sample standard deviation `STDDEV()' Return the population standard deviation `SUM()' Return the sum `VAR_POP()' Return the population standard variance `VAR_SAMP()' Return the sample variance `VARIANCE()' Return the population standard variance This section describes group (aggregate) functions that operate on sets of values. Unless otherwise stated, group functions ignore `NULL' values. If you use a group function in a statement containing no `GROUP BY' clause, it is equivalent to grouping on all rows. For more information, see *Note group-by-hidden-columns::. For numeric arguments, the variance and standard deviation functions return a *Note `DOUBLE': numeric-types. value. The `SUM()' and `AVG()' functions return a *Note `DECIMAL': numeric-types. value for exact-value arguments (integer or *Note `DECIMAL': numeric-types.), and a *Note `DOUBLE': numeric-types. value for approximate-value arguments (*Note `FLOAT': numeric-types. or *Note `DOUBLE': numeric-types.). The `SUM()' and `AVG()' aggregate functions do not work with temporal values. (They convert the values to numbers, losing everything after the first nonnumeric character.) To work around this problem, you can convert to numeric units, perform the aggregate operation, and convert back to a temporal value. Examples: SELECT SEC_TO_TIME(SUM(TIME_TO_SEC(TIME_COL))) FROM TBL_NAME; SELECT FROM_DAYS(SUM(TO_DAYS(DATE_COL))) FROM TBL_NAME; Functions such as `SUM()' or `AVG()' that expect a numeric argument cast the argument to a number if necessary. For *Note `SET': set. or *Note `ENUM': enum. values, the cast operation causes the underlying numeric value to be used. * `AVG([DISTINCT] EXPR)' Returns the average value of `EXPR'. The `DISTINCT' option can be used to return the average of the distinct values of EXPR. `AVG()' returns `NULL' if there were no matching rows. mysql> SELECT student_name, AVG(test_score) -> FROM student -> GROUP BY student_name; * `BIT_AND(EXPR)' Returns the bitwise `AND' of all bits in EXPR. The calculation is performed with 64-bit (*Note `BIGINT': numeric-types.) precision. This function returns `18446744073709551615' if there were no matching rows. (This is the value of an unsigned *Note `BIGINT': numeric-types. value with all bits set to 1.) * `BIT_OR(EXPR)' Returns the bitwise `OR' of all bits in EXPR. The calculation is performed with 64-bit (*Note `BIGINT': numeric-types.) precision. This function returns `0' if there were no matching rows. * `BIT_XOR(EXPR)' Returns the bitwise `XOR' of all bits in EXPR. The calculation is performed with 64-bit (*Note `BIGINT': numeric-types.) precision. This function returns `0' if there were no matching rows. * `COUNT(EXPR)' Returns a count of the number of non-`NULL' values of EXPR in the rows retrieved by a *Note `SELECT': select. statement. The result is a *Note `BIGINT': numeric-types. value. `COUNT()' returns `0' if there were no matching rows. mysql> SELECT student.student_name,COUNT(*) -> FROM student,course -> WHERE student.student_id=course.student_id -> GROUP BY student_name; `COUNT(*)' is somewhat different in that it returns a count of the number of rows retrieved, whether or not they contain `NULL' values. `COUNT(*)' is optimized to return very quickly if the *Note `SELECT': select. retrieves from one table, no other columns are retrieved, and there is no `WHERE' clause. For example: mysql> SELECT COUNT(*) FROM student; This optimization applies only to `MyISAM' tables only, because an exact row count is stored for this storage engine and can be accessed very quickly. For transactional storage engines such as `InnoDB', storing an exact row count is more problematic because multiple transactions may be occurring, each of which may affect the count. * `COUNT(DISTINCT EXPR,[EXPR...])' Returns a count of the number of rows with different non-`NULL' EXPR values. `COUNT(DISTINCT)' returns `0' if there were no matching rows. mysql> SELECT COUNT(DISTINCT results) FROM student; In MySQL, you can obtain the number of distinct expression combinations that do not contain `NULL' by giving a list of expressions. In standard SQL, you would have to do a concatenation of all expressions inside `COUNT(DISTINCT ...)'. * `GROUP_CONCAT(EXPR)' This function returns a string result with the concatenated non-`NULL' values from a group. It returns `NULL' if there are no non-`NULL' values. The full syntax is as follows: GROUP_CONCAT([DISTINCT] EXPR [,EXPR ...] [ORDER BY {UNSIGNED_INTEGER | COL_NAME | EXPR} [ASC | DESC] [,COL_NAME ...]] [SEPARATOR STR_VAL]) mysql> SELECT student_name, -> GROUP_CONCAT(test_score) -> FROM student -> GROUP BY student_name; Or: mysql> SELECT student_name, -> GROUP_CONCAT(DISTINCT test_score -> ORDER BY test_score DESC SEPARATOR ' ') -> FROM student -> GROUP BY student_name; In MySQL, you can get the concatenated values of expression combinations. To eliminate duplicate values, use the `DISTINCT' clause. To sort values in the result, use the `ORDER BY' clause. To sort in reverse order, add the `DESC' (descending) keyword to the name of the column you are sorting by in the `ORDER BY' clause. The default is ascending order; this may be specified explicitly using the `ASC' keyword. The default separator between values in a group is comma (``,''). To specify a separator explicitly, use `SEPARATOR' followed by the string value that should be inserted between group values. To eliminate the separator altogether, specify `SEPARATOR '''. The result is truncated to the maximum length that is given by the `group_concat_max_len' system variable, which has a default value of 1024. The value can be set higher, although the effective maximum length of the return value is constrained by the value of `max_allowed_packet'. The syntax to change the value of `group_concat_max_len' at runtime is as follows, where VAL is an unsigned integer: SET [GLOBAL | SESSION] group_concat_max_len = VAL; The return value is a nonbinary or binary string, depending on whether the arguments are nonbinary or binary strings. The result type is *Note `TEXT': blob. or *Note `BLOB': blob. unless `group_concat_max_len' is less than or equal to 512, in which case the result type is *Note `VARCHAR': char. or *Note `VARBINARY': binary-varbinary. See also `CONCAT()' and `CONCAT_WS()': *Note string-functions::. * `MAX([DISTINCT] EXPR)' Returns the maximum value of EXPR. `MAX()' may take a string argument; in such cases, it returns the maximum string value. See *Note mysql-indexes::. The `DISTINCT' keyword can be used to find the maximum of the distinct values of EXPR, however, this produces the same result as omitting `DISTINCT'. `MAX()' returns `NULL' if there were no matching rows. mysql> SELECT student_name, MIN(test_score), MAX(test_score) -> FROM student -> GROUP BY student_name; For `MAX()', MySQL currently compares *Note `ENUM': enum. and *Note `SET': set. columns by their string value rather than by the string's relative position in the set. This differs from how `ORDER BY' compares them. This is expected to be rectified in a future MySQL release. * `MIN([DISTINCT] EXPR)' Returns the minimum value of EXPR. `MIN()' may take a string argument; in such cases, it returns the minimum string value. See *Note mysql-indexes::. The `DISTINCT' keyword can be used to find the minimum of the distinct values of EXPR, however, this produces the same result as omitting `DISTINCT'. `MIN()' returns `NULL' if there were no matching rows. mysql> SELECT student_name, MIN(test_score), MAX(test_score) -> FROM student -> GROUP BY student_name; For `MIN()', MySQL currently compares *Note `ENUM': enum. and *Note `SET': set. columns by their string value rather than by the string's relative position in the set. This differs from how `ORDER BY' compares them. This is expected to be rectified in a future MySQL release. * `STD(EXPR)' Returns the population standard deviation of EXPR. This is an extension to standard SQL. The standard SQL function `STDDEV_POP()' can be used instead. This function returns `NULL' if there were no matching rows. * `STDDEV(EXPR)' Returns the population standard deviation of EXPR. This function is provided for compatibility with Oracle. The standard SQL function `STDDEV_POP()' can be used instead. This function returns `NULL' if there were no matching rows. * `STDDEV_POP(EXPR)' Returns the population standard deviation of EXPR (the square root of `VAR_POP()'). You can also use `STD()' or `STDDEV()', which are equivalent but not standard SQL. `STDDEV_POP()' returns `NULL' if there were no matching rows. * `STDDEV_SAMP(EXPR)' Returns the sample standard deviation of EXPR (the square root of `VAR_SAMP()'. `STDDEV_SAMP()' returns `NULL' if there were no matching rows. * `SUM([DISTINCT] EXPR)' Returns the sum of EXPR. If the return set has no rows, `SUM()' returns `NULL'. The `DISTINCT' keyword can be used in MySQL 5.1 to sum only the distinct values of EXPR. `SUM()' returns `NULL' if there were no matching rows. * `VAR_POP(EXPR)' Returns the population standard variance of EXPR. It considers rows as the whole population, not as a sample, so it has the number of rows as the denominator. You can also use `VARIANCE()', which is equivalent but is not standard SQL. `VAR_POP()' returns `NULL' if there were no matching rows. * `VAR_SAMP(EXPR)' Returns the sample variance of EXPR. That is, the denominator is the number of rows minus one. `VAR_SAMP()' returns `NULL' if there were no matching rows. * `VARIANCE(EXPR)' Returns the population standard variance of EXPR. This is an extension to standard SQL. The standard SQL function `VAR_POP()' can be used instead. `VARIANCE()' returns `NULL' if there were no matching rows.  File: manual.info, Node: group-by-modifiers, Next: group-by-hidden-columns, Prev: group-by-functions, Up: group-by-functions-and-modifiers 12.16.2 `GROUP BY' Modifiers ---------------------------- The `GROUP BY' clause permits a `WITH ROLLUP' modifier that causes extra rows to be added to the summary output. These rows represent higher-level (or super-aggregate) summary operations. `ROLLUP' thus enables you to answer questions at multiple levels of analysis with a single query. It can be used, for example, to provide support for OLAP (Online Analytical Processing) operations. Suppose that a table named `sales' has `year', `country', `product', and `profit' columns for recording sales profitability: CREATE TABLE sales ( year INT NOT NULL, country VARCHAR(20) NOT NULL, product VARCHAR(32) NOT NULL, profit INT ); The table's contents can be summarized per year with a simple `GROUP BY' like this: mysql> SELECT year, SUM(profit) FROM sales GROUP BY year; +------+-------------+ | year | SUM(profit) | +------+-------------+ | 2000 | 4525 | | 2001 | 3010 | +------+-------------+ This output shows the total profit for each year, but if you also want to determine the total profit summed over all years, you must add up the individual values yourself or run an additional query. Or you can use `ROLLUP', which provides both levels of analysis with a single query. Adding a `WITH ROLLUP' modifier to the `GROUP BY' clause causes the query to produce another row that shows the grand total over all year values: mysql> SELECT year, SUM(profit) FROM sales GROUP BY year WITH ROLLUP; +------+-------------+ | year | SUM(profit) | +------+-------------+ | 2000 | 4525 | | 2001 | 3010 | | NULL | 7535 | +------+-------------+ The grand total super-aggregate line is identified by the value `NULL' in the `year' column. `ROLLUP' has a more complex effect when there are multiple `GROUP BY' columns. In this case, each time there is a `break' (change in value) in any but the last grouping column, the query produces an extra super-aggregate summary row. For example, without `ROLLUP', a summary on the `sales' table based on `year', `country', and `product' might look like this: mysql> SELECT year, country, product, SUM(profit) -> FROM sales -> GROUP BY year, country, product; +------+---------+------------+-------------+ | year | country | product | SUM(profit) | +------+---------+------------+-------------+ | 2000 | Finland | Computer | 1500 | | 2000 | Finland | Phone | 100 | | 2000 | India | Calculator | 150 | | 2000 | India | Computer | 1200 | | 2000 | USA | Calculator | 75 | | 2000 | USA | Computer | 1500 | | 2001 | Finland | Phone | 10 | | 2001 | USA | Calculator | 50 | | 2001 | USA | Computer | 2700 | | 2001 | USA | TV | 250 | +------+---------+------------+-------------+ The output indicates summary values only at the year/country/product level of analysis. When `ROLLUP' is added, the query produces several extra rows: mysql> SELECT year, country, product, SUM(profit) -> FROM sales -> GROUP BY year, country, product WITH ROLLUP; +------+---------+------------+-------------+ | year | country | product | SUM(profit) | +------+---------+------------+-------------+ | 2000 | Finland | Computer | 1500 | | 2000 | Finland | Phone | 100 | | 2000 | Finland | NULL | 1600 | | 2000 | India | Calculator | 150 | | 2000 | India | Computer | 1200 | | 2000 | India | NULL | 1350 | | 2000 | USA | Calculator | 75 | | 2000 | USA | Computer | 1500 | | 2000 | USA | NULL | 1575 | | 2000 | NULL | NULL | 4525 | | 2001 | Finland | Phone | 10 | | 2001 | Finland | NULL | 10 | | 2001 | USA | Calculator | 50 | | 2001 | USA | Computer | 2700 | | 2001 | USA | TV | 250 | | 2001 | USA | NULL | 3000 | | 2001 | NULL | NULL | 3010 | | NULL | NULL | NULL | 7535 | +------+---------+------------+-------------+ For this query, adding `ROLLUP' causes the output to include summary information at four levels of analysis, not just one. Here is how to interpret the `ROLLUP' output: * Following each set of product rows for a given year and country, an extra summary row is produced showing the total for all products. These rows have the `product' column set to `NULL'. * Following each set of rows for a given year, an extra summary row is produced showing the total for all countries and products. These rows have the `country' and `products' columns set to `NULL'. * Finally, following all other rows, an extra summary row is produced showing the grand total for all years, countries, and products. This row has the `year', `country', and `products' columns set to `NULL'. *Other Considerations When using `ROLLUP'* The following items list some behaviors specific to the MySQL implementation of `ROLLUP': When you use `ROLLUP', you cannot also use an `ORDER BY' clause to sort the results. In other words, `ROLLUP' and `ORDER BY' are mutually exclusive. However, you still have some control over sort order. `GROUP BY' in MySQL sorts results, and you can use explicit `ASC' and `DESC' keywords with columns named in the `GROUP BY' list to specify sort order for individual columns. (The higher-level summary rows added by `ROLLUP' still appear after the rows from which they are calculated, regardless of the sort order.) `LIMIT' can be used to restrict the number of rows returned to the client. `LIMIT' is applied after `ROLLUP', so the limit applies against the extra rows added by `ROLLUP'. For example: mysql> SELECT year, country, product, SUM(profit) -> FROM sales -> GROUP BY year, country, product WITH ROLLUP -> LIMIT 5; +------+---------+------------+-------------+ | year | country | product | SUM(profit) | +------+---------+------------+-------------+ | 2000 | Finland | Computer | 1500 | | 2000 | Finland | Phone | 100 | | 2000 | Finland | NULL | 1600 | | 2000 | India | Calculator | 150 | | 2000 | India | Computer | 1200 | +------+---------+------------+-------------+ Using `LIMIT' with `ROLLUP' may produce results that are more difficult to interpret, because you have less context for understanding the super-aggregate rows. The `NULL' indicators in each super-aggregate row are produced when the row is sent to the client. The server looks at the columns named in the `GROUP BY' clause following the leftmost one that has changed value. For any column in the result set with a name that is a lexical match to any of those names, its value is set to `NULL'. (If you specify grouping columns by column number, the server identifies which columns to set to `NULL' by number.) Because the `NULL' values in the super-aggregate rows are placed into the result set at such a late stage in query processing, you cannot test them as `NULL' values within the query itself. For example, you cannot add `HAVING product IS NULL' to the query to eliminate from the output all but the super-aggregate rows. On the other hand, the `NULL' values do appear as `NULL' on the client side and can be tested as such using any MySQL client programming interface.  File: manual.info, Node: group-by-hidden-columns, Prev: group-by-modifiers, Up: group-by-functions-and-modifiers 12.16.3 `GROUP BY' and `HAVING' with Hidden Columns --------------------------------------------------- In standard SQL, a query that includes a `GROUP BY' clause cannot refer to nonaggregated columns in the select list that are not named in the `GROUP BY' clause. For example, this query is illegal in standard SQL because the `name' column in the select list does not appear in the `GROUP BY': SELECT o.custid, c.name, MAX(o.payment) FROM orders AS o, customers AS c WHERE o.custid = c.custid GROUP BY o.custid; For the query to be legal, the `name' column must be omitted from the select list or named in the `GROUP BY' clause. MySQL extends the use of `GROUP BY' so that the select list can refer to nonaggregated columns not named in the `GROUP BY' clause. This means that the preceding query is legal in MySQL. You can use this feature to get better performance by avoiding unnecessary column sorting and grouping. However, this is useful primarily when all values in each nonaggregated column not named in the `GROUP BY' are the same for each group. The server is free to choose any value from each group, so unless they are the same, the values chosen are indeterminate. Furthermore, the selection of values from each group cannot be influenced by adding an `ORDER BY' clause. Sorting of the result set occurs after values have been chosen, and `ORDER BY' does not affect which values the server chooses. A similar MySQL extension applies to the `HAVING' clause. Standard SQL does not permit the `HAVING' clause to name any column not found in the `GROUP BY' clause unless it is enclosed in an aggregate function. MySQL permits the use of such columns to simplify calculations. This extension assumes that the nongrouped columns will have the same group-wise values. Otherwise, the result is indeterminate. To disable the MySQL `GROUP BY' extension, enable the `ONLY_FULL_GROUP_BY' SQL mode. This enables standard SQL behavior: Columns not named in the `GROUP BY' clause cannot be used in the select list or `HAVING' clause unless enclosed in an aggregate function. For example, the following query returns `name' values that occur only once in table `orders': SELECT name, COUNT(name) FROM orders GROUP BY name HAVING COUNT(name) = 1; However, the result of the following similar query that uses an alias for the aggregated column depends on the SQL mode: SELECT name, COUNT(name) AS c FROM orders GROUP BY name HAVING c = 1; In this case, a `non-grouping field 'c' is used in HAVING clause' error occurs if `ONLY_FULL_GROUP_BY' is enabled because the extension does not apply. The column `c' in the `HAVING' clause is not enclosed in an aggregate function (instead, it _is_ an aggregate function). The select list extension also applies to `ORDER BY'. That is, you can use nonaggregated columns in the `ORDER BY' clause that do not appear in the `GROUP BY' clause. (However, as mentioned previously, `ORDER BY' does not affect which values are chosen from nonaggregated columns; it only sorts them after they have been chosen.) This extension does not apply if the `ONLY_FULL_GROUP_BY' SQL mode is enabled. In some cases, you can use `MIN()' and `MAX()' to obtain a specific column value even if it is not unique. If the `sort' column contains integers no larger than 6 digits, the following query gives the value of `column' from the row containing the smallest `sort' value: SUBSTR(MIN(CONCAT(LPAD(sort,6,'0'),column)),7) See *Note example-maximum-column-group-row::. If you are trying to follow standard SQL, you cannot use expressions in `GROUP BY' clauses. As a workaround, use an alias for the expression: SELECT id, FLOOR(value/100) AS val FROM TBL_NAME GROUP BY id, val; MySQL permits expressions in `GROUP BY' clauses, so the alias is unnecessary: SELECT id, FLOOR(value/100) FROM TBL_NAME GROUP BY id, FLOOR(value/100);  File: manual.info, Node: spatial-extensions, Next: precision-math, Prev: group-by-functions-and-modifiers, Up: functions 12.17 Spatial Extensions ======================== * Menu: * gis-introduction:: Introduction to MySQL Spatial Support * opengis-geometry-model:: The OpenGIS Geometry Model * supported-spatial-data-formats:: Supported Spatial Data Formats * creating-a-spatially-enabled-mysql-database:: Creating a Spatially Enabled MySQL Database * spatial-analysis-functions:: Spatial Analysis Functions * optimizing-spatial-analysis:: Optimizing Spatial Analysis * mysql-gis-conformance-and-compatibility:: MySQL Conformance and Compatibility MySQL supports spatial extensions to enable the generation, storage, and analysis of geographic features. These features are available for `MyISAM', `InnoDB', *Note `NDB': mysql-cluster, and `ARCHIVE' tables. For spatial columns, `MyISAM' supports both `SPATIAL' and non-`SPATIAL' indexes. Other storage engines support non-`SPATIAL' indexes, as described in *Note create-index::. This chapter covers the following topics: * The basis of these spatial extensions in the OpenGIS geometry model * Data formats for representing spatial data * How to use spatial data in MySQL * Use of indexing for spatial data * MySQL differences from the OpenGIS specification * Additional Resources * * The Open Geospatial Consortium publishes the `OpenGIS(R) Simple Features Specifications For SQL', a document that proposes several conceptual ways for extending an SQL RDBMS to support spatial data. This specification is available from the OGC Web site at `http://www.opengis.org/docs/99-049.pdf'. * If you have questions or concerns about the use of the spatial extensions to MySQL, you can discuss them in the GIS forum: `http://forums.mysql.com/list.php?23'.  File: manual.info, Node: gis-introduction, Next: opengis-geometry-model, Prev: spatial-extensions, Up: spatial-extensions 12.17.1 Introduction to MySQL Spatial Support --------------------------------------------- MySQL implements spatial extensions following the specification of the Open Geospatial Consortium (OGC). This is an international consortium of more than 250 companies, agencies, and universities participating in the development of publicly available conceptual solutions that can be useful with all kinds of applications that manage spatial data. The OGC maintains a Web site at `http://www.opengis.org/'. In 1997, the Open Geospatial Consortium published the `OpenGIS(R) Simple Features Specifications For SQL', a document that proposes several conceptual ways for extending an SQL RDBMS to support spatial data. This specification is available from the OGC Web site at `http://www.opengis.org/docs/99-049.pdf'. It contains additional information relevant to this chapter. MySQL implements a subset of the *SQL with Geometry Types* environment proposed by OGC. This term refers to an SQL environment that has been extended with a set of geometry types. A geometry-valued SQL column is implemented as a column that has a geometry type. The specification describe a set of SQL geometry types, as well as functions on those types to create and analyze geometry values. A *geographic feature* is anything in the world that has a location. A feature can be: * An entity. For example, a mountain, a pond, a city. * A space. For example, town district, the tropics. * A definable location. For example, a crossroad, as a particular place where two streets intersect. Some documents use the term *geospatial feature* to refer to geographic features. *Geometry* is another word that denotes a geographic feature. Originally the word *geometry* meant measurement of the earth. Another meaning comes from cartography, referring to the geometric features that cartographers use to map the world. This chapter uses all of these terms synonymously: *geographic feature*, *geospatial feature*, *feature*, or *geometry*. Here, the term most commonly used is *geometry*, defined as _a point or an aggregate of points representing anything in the world that has a location_.  File: manual.info, Node: opengis-geometry-model, Next: supported-spatial-data-formats, Prev: gis-introduction, Up: spatial-extensions 12.17.2 The OpenGIS Geometry Model ---------------------------------- * Menu: * gis-geometry-class-hierarchy:: The Geometry Class Hierarchy * gis-class-geometry:: Class `Geometry' * gis-class-point:: Class `Point' * gis-class-curve:: Class `Curve' * gis-class-linestring:: Class `LineString' * gis-class-surface:: Class `Surface' * gis-class-polygon:: Class `Polygon' * gis-class-geometrycollection:: Class `GeometryCollection' * gis-class-multipoint:: Class `MultiPoint' * gis-class-multicurve:: Class `MultiCurve' * gis-class-multilinestring:: Class `MultiLineString' * gis-class-multisurface:: Class `MultiSurface' * gis-class-multipolygon:: Class `MultiPolygon' The set of geometry types proposed by OGC's *SQL with Geometry Types* environment is based on the *OpenGIS Geometry Model*. In this model, each geometric object has the following general properties: * It is associated with a Spatial Reference System, which describes the coordinate space in which the object is defined. * It belongs to some geometry class.  File: manual.info, Node: gis-geometry-class-hierarchy, Next: gis-class-geometry, Prev: opengis-geometry-model, Up: opengis-geometry-model 12.17.2.1 The Geometry Class Hierarchy ...................................... The geometry classes define a hierarchy as follows: * `Geometry' (noninstantiable) * `Point' (instantiable) * `Curve' (noninstantiable) * `LineString' (instantiable) * `Line' * `LinearRing' * `Surface' (noninstantiable) * `Polygon' (instantiable) * `GeometryCollection' (instantiable) * `MultiPoint' (instantiable) * `MultiCurve' (noninstantiable) * `MultiLineString' (instantiable) * `MultiSurface' (noninstantiable) * `MultiPolygon' (instantiable) It is not possible to create objects in noninstantiable classes. It is possible to create objects in instantiable classes. All classes have properties, and instantiable classes may also have assertions (rules that define valid class instances). `Geometry' is the base class. It is an abstract class. The instantiable subclasses of `Geometry' are restricted to zero-, one-, and two-dimensional geometric objects that exist in two-dimensional coordinate space. All instantiable geometry classes are defined so that valid instances of a geometry class are topologically closed (that is, all defined geometries include their boundary). The base `Geometry' class has subclasses for `Point', `Curve', `Surface', and `GeometryCollection': * `Point' represents zero-dimensional objects. * `Curve' represents one-dimensional objects, and has subclass `LineString', with sub-subclasses `Line' and `LinearRing'. * `Surface' is designed for two-dimensional objects and has subclass `Polygon'. * `GeometryCollection' has specialized zero-, one-, and two-dimensional collection classes named `MultiPoint', `MultiLineString', and `MultiPolygon' for modeling geometries corresponding to collections of `Points', `LineStrings', and `Polygons', respectively. `MultiCurve' and `MultiSurface' are introduced as abstract superclasses that generalize the collection interfaces to handle `Curves' and `Surfaces'. `Geometry', `Curve', `Surface', `MultiCurve', and `MultiSurface' are defined as noninstantiable classes. They define a common set of methods for their subclasses and are included for extensibility. `Point', `LineString', `Polygon', `GeometryCollection', `MultiPoint', `MultiLineString', and `MultiPolygon' are instantiable classes.  File: manual.info, Node: gis-class-geometry, Next: gis-class-point, Prev: gis-geometry-class-hierarchy, Up: opengis-geometry-model 12.17.2.2 Class `Geometry' .......................... `Geometry' is the root class of the hierarchy. It is a noninstantiable class but has a number of properties that are common to all geometry values created from any of the `Geometry' subclasses. These properties are described in the following list. Particular subclasses have their own specific properties, described later. *Geometry Properties* A geometry value has the following properties: * Its *type*. Each geometry belongs to one of the instantiable classes in the hierarchy. * Its *SRID*, or Spatial Reference Identifier. This value identifies the geometry's associated Spatial Reference System that describes the coordinate space in which the geometry object is defined. In MySQL, the SRID value is just an integer associated with the geometry value. All calculations are done assuming Euclidean (planar) geometry. * Its *coordinates* in its Spatial Reference System, represented as double-precision (eight-byte) numbers. All nonempty geometries include at least one pair of (X,Y) coordinates. Empty geometries contain no coordinates. Coordinates are related to the SRID. For example, in different coordinate systems, the distance between two objects may differ even when objects have the same coordinates, because the distance on the *planar* coordinate system and the distance on the *geocentric* system (coordinates on the Earth's surface) are different things. * Its *interior*, *boundary*, and *exterior*. Every geometry occupies some position in space. The exterior of a geometry is all space not occupied by the geometry. The interior is the space occupied by the geometry. The boundary is the interface between the geometry's interior and exterior. * Its *MBR* (Minimum Bounding Rectangle), or Envelope. This is the bounding geometry, formed by the minimum and maximum (X,Y) coordinates: ((MINX MINY, MAXX MINY, MAXX MAXY, MINX MAXY, MINX MINY)) * Whether the value is *simple* or *nonsimple*. Geometry values of types (`LineString', `MultiPoint', `MultiLineString') are either simple or nonsimple. Each type determines its own assertions for being simple or nonsimple. * Whether the value is *closed* or *not closed*. Geometry values of types (`LineString', `MultiString') are either closed or not closed. Each type determines its own assertions for being closed or not closed. * Whether the value is *empty* or *nonempty* A geometry is empty if it does not have any points. Exterior, interior, and boundary of an empty geometry are not defined (that is, they are represented by a `NULL' value). An empty geometry is defined to be always simple and has an area of 0. * Its *dimension*. A geometry can have a dimension of -1, 0, 1, or 2: * -1 for an empty geometry. * 0 for a geometry with no length and no area. * 1 for a geometry with nonzero length and zero area. * 2 for a geometry with nonzero area. `Point' objects have a dimension of zero. `LineString' objects have a dimension of 1. `Polygon' objects have a dimension of 2. The dimensions of `MultiPoint', `MultiLineString', and `MultiPolygon' objects are the same as the dimensions of the elements they consist of.  File: manual.info, Node: gis-class-point, Next: gis-class-curve, Prev: gis-class-geometry, Up: opengis-geometry-model 12.17.2.3 Class `Point' ....................... A `Point' is a geometry that represents a single location in coordinate space. *`Point' Examples* * Imagine a large-scale map of the world with many cities. A `Point' object could represent each city. * On a city map, a `Point' object could represent a bus stop. *`Point' Properties* * X-coordinate value. * Y-coordinate value. * `Point' is defined as a zero-dimensional geometry. * The boundary of a `Point' is the empty set.  File: manual.info, Node: gis-class-curve, Next: gis-class-linestring, Prev: gis-class-point, Up: opengis-geometry-model 12.17.2.4 Class `Curve' ....................... A `Curve' is a one-dimensional geometry, usually represented by a sequence of points. Particular subclasses of `Curve' define the type of interpolation between points. `Curve' is a noninstantiable class. *`Curve' Properties* * A `Curve' has the coordinates of its points. * A `Curve' is defined as a one-dimensional geometry. * A `Curve' is simple if it does not pass through the same point twice. * A `Curve' is closed if its start point is equal to its endpoint. * The boundary of a closed `Curve' is empty. * The boundary of a nonclosed `Curve' consists of its two endpoints. * A `Curve' that is simple and closed is a `LinearRing'.  File: manual.info, Node: gis-class-linestring, Next: gis-class-surface, Prev: gis-class-curve, Up: opengis-geometry-model 12.17.2.5 Class `LineString' ............................ A `LineString' is a `Curve' with linear interpolation between points. *`LineString' Examples* * On a world map, `LineString' objects could represent rivers. * In a city map, `LineString' objects could represent streets. *`LineString' Properties* * A `LineString' has coordinates of segments, defined by each consecutive pair of points. * A `LineString' is a `Line' if it consists of exactly two points. * A `LineString' is a `LinearRing' if it is both closed and simple.  File: manual.info, Node: gis-class-surface, Next: gis-class-polygon, Prev: gis-class-linestring, Up: opengis-geometry-model 12.17.2.6 Class `Surface' ......................... A `Surface' is a two-dimensional geometry. It is a noninstantiable class. Its only instantiable subclass is `Polygon'. *`Surface' Properties* * A `Surface' is defined as a two-dimensional geometry. * The OpenGIS specification defines a simple `Surface' as a geometry that consists of a single `patch' that is associated with a single exterior boundary and zero or more interior boundaries. * The boundary of a simple `Surface' is the set of closed curves corresponding to its exterior and interior boundaries.  File: manual.info, Node: gis-class-polygon, Next: gis-class-geometrycollection, Prev: gis-class-surface, Up: opengis-geometry-model 12.17.2.7 Class `Polygon' ......................... A `Polygon' is a planar `Surface' representing a multisided geometry. It is defined by a single exterior boundary and zero or more interior boundaries, where each interior boundary defines a hole in the `Polygon'. *`Polygon' Examples* * On a region map, `Polygon' objects could represent forests, districts, and so on. *`Polygon' Assertions* * The boundary of a `Polygon' consists of a set of `LinearRing' objects (that is, `LineString' objects that are both simple and closed) that make up its exterior and interior boundaries. * A `Polygon' has no rings that cross. The rings in the boundary of a `Polygon' may intersect at a `Point', but only as a tangent. * A `Polygon' has no lines, spikes, or punctures. * A `Polygon' has an interior that is a connected point set. * A `Polygon' may have holes. The exterior of a `Polygon' with holes is not connected. Each hole defines a connected component of the exterior. The preceding assertions make a `Polygon' a simple geometry.  File: manual.info, Node: gis-class-geometrycollection, Next: gis-class-multipoint, Prev: gis-class-polygon, Up: opengis-geometry-model 12.17.2.8 Class `GeometryCollection' .................................... A `GeometryCollection' is a geometry that is a collection of one or more geometries of any class. All the elements in a `GeometryCollection' must be in the same Spatial Reference System (that is, in the same coordinate system). There are no other constraints on the elements of a `GeometryCollection', although the subclasses of `GeometryCollection' described in the following sections may restrict membership. Restrictions may be based on: * Element type (for example, a `MultiPoint' may contain only `Point' elements) * Dimension * Constraints on the degree of spatial overlap between elements  File: manual.info, Node: gis-class-multipoint, Next: gis-class-multicurve, Prev: gis-class-geometrycollection, Up: opengis-geometry-model 12.17.2.9 Class `MultiPoint' ............................ A `MultiPoint' is a geometry collection composed of `Point' elements. The points are not connected or ordered in any way. *`MultiPoint' Examples* * On a world map, a `MultiPoint' could represent a chain of small islands. * On a city map, a `MultiPoint' could represent the outlets for a ticket office. *`MultiPoint' Properties* * A `MultiPoint' is a zero-dimensional geometry. * A `MultiPoint' is simple if no two of its `Point' values are equal (have identical coordinate values). * The boundary of a `MultiPoint' is the empty set.  File: manual.info, Node: gis-class-multicurve, Next: gis-class-multilinestring, Prev: gis-class-multipoint, Up: opengis-geometry-model 12.17.2.10 Class `MultiCurve' ............................. A `MultiCurve' is a geometry collection composed of `Curve' elements. `MultiCurve' is a noninstantiable class. *`MultiCurve' Properties* * A `MultiCurve' is a one-dimensional geometry. * A `MultiCurve' is simple if and only if all of its elements are simple; the only intersections between any two elements occur at points that are on the boundaries of both elements. * A `MultiCurve' boundary is obtained by applying the `mod 2 union rule' (also known as the `odd-even rule'): A point is in the boundary of a `MultiCurve' if it is in the boundaries of an odd number of `MultiCurve' elements. * A `MultiCurve' is closed if all of its elements are closed. * The boundary of a closed `MultiCurve' is always empty.  File: manual.info, Node: gis-class-multilinestring, Next: gis-class-multisurface, Prev: gis-class-multicurve, Up: opengis-geometry-model 12.17.2.11 Class `MultiLineString' .................................. A `MultiLineString' is a `MultiCurve' geometry collection composed of `LineString' elements. *`MultiLineString' Examples* * On a region map, a `MultiLineString' could represent a river system or a highway system.  File: manual.info, Node: gis-class-multisurface, Next: gis-class-multipolygon, Prev: gis-class-multilinestring, Up: opengis-geometry-model 12.17.2.12 Class `MultiSurface' ............................... A `MultiSurface' is a geometry collection composed of surface elements. `MultiSurface' is a noninstantiable class. Its only instantiable subclass is `MultiPolygon'. *`MultiSurface' Assertions* * Two `MultiSurface' surfaces have no interiors that intersect. * Two `MultiSurface' elements have boundaries that intersect at most at a finite number of points.  File: manual.info, Node: gis-class-multipolygon, Prev: gis-class-multisurface, Up: opengis-geometry-model 12.17.2.13 Class `MultiPolygon' ............................... A `MultiPolygon' is a `MultiSurface' object composed of `Polygon' elements. *`MultiPolygon' Examples* * On a region map, a `MultiPolygon' could represent a system of lakes. *`MultiPolygon' Assertions* * A `MultiPolygon' has no two `Polygon' elements with interiors that intersect. * A `MultiPolygon' has no two `Polygon' elements that cross (crossing is also forbidden by the previous assertion), or that touch at an infinite number of points. * A `MultiPolygon' may not have cut lines, spikes, or punctures. A `MultiPolygon' is a regular, closed point set. * A `MultiPolygon' that has more than one `Polygon' has an interior that is not connected. The number of connected components of the interior of a `MultiPolygon' is equal to the number of `Polygon' values in the `MultiPolygon'. *`MultiPolygon' Properties* * A `MultiPolygon' is a two-dimensional geometry. * A `MultiPolygon' boundary is a set of closed curves (`LineString' values) corresponding to the boundaries of its `Polygon' elements. * Each `Curve' in the boundary of the `MultiPolygon' is in the boundary of exactly one `Polygon' element. * Every `Curve' in the boundary of an `Polygon' element is in the boundary of the `MultiPolygon'.  File: manual.info, Node: supported-spatial-data-formats, Next: creating-a-spatially-enabled-mysql-database, Prev: opengis-geometry-model, Up: spatial-extensions 12.17.3 Supported Spatial Data Formats -------------------------------------- * Menu: * gis-wkt-format:: Well-Known Text (WKT) Format * gis-wkb-format:: Well-Known Binary (WKB) Format This section describes the standard spatial data formats that are used to represent geometry objects in queries. They are: * Well-Known Text (WKT) format * Well-Known Binary (WKB) format Internally, MySQL stores geometry values in a format that is not identical to either WKT or WKB format.  File: manual.info, Node: gis-wkt-format, Next: gis-wkb-format, Prev: supported-spatial-data-formats, Up: supported-spatial-data-formats 12.17.3.1 Well-Known Text (WKT) Format ...................................... The Well-Known Text (WKT) representation of Geometry is designed to exchange geometry data in ASCII form. For a Backus-Naur grammar that specifies the formal production rules for writing WKT values, see the OpenGIS specification document referenced in *Note spatial-extensions::. Examples of WKT representations of geometry objects: * A `Point': POINT(15 20) Note that point coordinates are specified with no separating comma. This differs from the syntax for the SQL `POINT()' function, which requires a comma between the coordinates. Take care to use the syntax appropriate to the context of a given spatial operation. For example, the following statements both extract the X-coordinate from a `Point' object. The first produces the object directly using the `POINT()' function. The second uses a WKT representation converted to a `Point' with `GeomFromText()'. mysql> SELECT X(POINT(15, 20)); +------------------+ | X(POINT(15, 20)) | +------------------+ | 15 | +------------------+ mysql> SELECT X(GeomFromText('POINT(15 20)')); +---------------------------------+ | X(GeomFromText('POINT(15 20)')) | +---------------------------------+ | 15 | +---------------------------------+ * A `LineString' with four points: LINESTRING(0 0, 10 10, 20 25, 50 60) Note that point coordinate pairs are separated by commas. * A `Polygon' with one exterior ring and one interior ring: POLYGON((0 0,10 0,10 10,0 10,0 0),(5 5,7 5,7 7,5 7, 5 5)) * A `MultiPoint' with three `Point' values: MULTIPOINT(0 0, 20 20, 60 60) * A `MultiLineString' with two `LineString' values: MULTILINESTRING((10 10, 20 20), (15 15, 30 15)) * A `MultiPolygon' with two `Polygon' values: MULTIPOLYGON(((0 0,10 0,10 10,0 10,0 0)),((5 5,7 5,7 7,5 7, 5 5))) * A `GeometryCollection' consisting of two `Point' values and one `LineString': GEOMETRYCOLLECTION(POINT(10 10), POINT(30 30), LINESTRING(15 15, 20 20))  File: manual.info, Node: gis-wkb-format, Prev: gis-wkt-format, Up: supported-spatial-data-formats 12.17.3.2 Well-Known Binary (WKB) Format ........................................ The Well-Known Binary (WKB) representation for geometric values is defined by the OpenGIS specification. It is also defined in the ISO `SQL/MM Part 3: Spatial' standard. WKB is used to exchange geometry data as binary streams represented by *Note `BLOB': blob. values containing geometric WKB information. WKB uses one-byte unsigned integers, four-byte unsigned integers, and eight-byte double-precision numbers (IEEE 754 format). A byte is eight bits. For example, a WKB value that corresponds to `POINT(1 1)' consists of this sequence of 21 bytes (each represented here by two hex digits): 0101000000000000000000F03F000000000000F03F The sequence may be broken down into these components: Byte order : 01 WKB type : 01000000 X : 000000000000F03F Y : 000000000000F03F Component representation is as follows: * The byte order may be either 1 or 0 to indicate little-endian or big-endian storage. The little-endian and big-endian byte orders are also known as Network Data Representation (NDR) and External Data Representation (XDR), respectively. * The WKB type is a code that indicates the geometry type. Values from 1 through 7 indicate `Point', `LineString', `Polygon', `MultiPoint', `MultiLineString', `MultiPolygon', and `GeometryCollection'. * A `Point' value has X and Y coordinates, each represented as a double-precision value. WKB values for more complex geometry values are represented by more complex data structures, as detailed in the OpenGIS specification.  File: manual.info, Node: creating-a-spatially-enabled-mysql-database, Next: spatial-analysis-functions, Prev: supported-spatial-data-formats, Up: spatial-extensions 12.17.4 Creating a Spatially Enabled MySQL Database --------------------------------------------------- * Menu: * mysql-spatial-datatypes:: MySQL Spatial Data Types * creating-spatial-values:: Creating Spatial Values * creating-spatial-columns:: Creating Spatial Columns * populating-spatial-columns:: Populating Spatial Columns * fetching-spatial-data:: Fetching Spatial Data This section describes the data types you can use for representing spatial data in MySQL, and the functions available for creating and retrieving spatial values.  File: manual.info, Node: mysql-spatial-datatypes, Next: creating-spatial-values, Prev: creating-a-spatially-enabled-mysql-database, Up: creating-a-spatially-enabled-mysql-database 12.17.4.1 MySQL Spatial Data Types .................................. MySQL has data types that correspond to OpenGIS classes. Some of these types hold single geometry values: * `GEOMETRY' * `POINT' * `LINESTRING' * `POLYGON' `GEOMETRY' can store geometry values of any type. The other single-value types (`POINT', `LINESTRING', and `POLYGON') restrict their values to a particular geometry type. The other data types hold collections of values: * `MULTIPOINT' * `MULTILINESTRING' * `MULTIPOLYGON' * `GEOMETRYCOLLECTION' `GEOMETRYCOLLECTION' can store a collection of objects of any type. The other collection types (`MULTIPOINT', `MULTILINESTRING', `MULTIPOLYGON', and `GEOMETRYCOLLECTION') restrict collection members to those having a particular geometry type.  File: manual.info, Node: creating-spatial-values, Next: creating-spatial-columns, Prev: mysql-spatial-datatypes, Up: creating-a-spatially-enabled-mysql-database 12.17.4.2 Creating Spatial Values ................................. * Menu: * gis-wkt-functions:: Creating Geometry Values Using WKT Functions * gis-wkb-functions:: Creating Geometry Values Using WKB Functions * gis-mysql-specific-functions:: Creating Geometry Values Using MySQL-Specific Functions This section describes how to create spatial values using Well-Known Text and Well-Known Binary functions that are defined in the OpenGIS standard, and using MySQL-specific functions.  File: manual.info, Node: gis-wkt-functions, Next: gis-wkb-functions, Prev: creating-spatial-values, Up: creating-spatial-values 12.17.4.3 Creating Geometry Values Using WKT Functions ...................................................... MySQL provides a number of functions that take as arguments a Well-Known Text representation and, optionally, a spatial reference system identifier (SRID). They return the corresponding geometry. `GeomFromText()' accepts a WKT of any geometry type as its first argument. An implementation also provides type-specific construction functions for construction of geometry values of each geometry type. * `GeomCollFromText(WKT[,SRID])', `GeometryCollectionFromText(WKT[,SRID])' Constructs a `GEOMETRYCOLLECTION' value using its WKT representation and SRID. * `GeomFromText(WKT[,SRID])', `GeometryFromText(WKT[,SRID])' Constructs a geometry value of any type using its WKT representation and SRID. * `LineFromText(WKT[,SRID])', `LineStringFromText(WKT[,SRID])' Constructs a `LINESTRING' value using its WKT representation and SRID. * `MLineFromText(WKT[,SRID])', `MultiLineStringFromText(WKT[,SRID])' Constructs a `MULTILINESTRING' value using its WKT representation and SRID. * `MPointFromText(WKT[,SRID])', `MultiPointFromText(WKT[,SRID])' Constructs a `MULTIPOINT' value using its WKT representation and SRID. * `MPolyFromText(WKT[,SRID])', `MultiPolygonFromText(WKT[,SRID])' Constructs a `MULTIPOLYGON' value using its WKT representation and SRID. * `PointFromText(WKT[,SRID])' Constructs a `POINT' value using its WKT representation and SRID. * `PolyFromText(WKT[,SRID])', `PolygonFromText(WKT[,SRID])' Constructs a `POLYGON' value using its WKT representation and SRID. The OpenGIS specification also defines the following optional functions, which MySQL does not implement. These functions construct `Polygon' or `MultiPolygon' values based on the WKT representation of a collection of rings or closed `LineString' values. These values may intersect. * `BdMPolyFromText(WKT,SRID)' Constructs a `MultiPolygon' value from a `MultiLineString' value in WKT format containing an arbitrary collection of closed `LineString' values. * `BdPolyFromText(WKT,SRID)' Constructs a `Polygon' value from a `MultiLineString' value in WKT format containing an arbitrary collection of closed `LineString' values.  File: manual.info, Node: gis-wkb-functions, Next: gis-mysql-specific-functions, Prev: gis-wkt-functions, Up: creating-spatial-values 12.17.4.4 Creating Geometry Values Using WKB Functions ...................................................... MySQL provides a number of functions that take as arguments a *Note `BLOB': blob. containing a Well-Known Binary representation and, optionally, a spatial reference system identifier (SRID). They return the corresponding geometry. As of MySQL 5.1.35, these functions also accept geometry objects for compatibility with the changes made in MySQL 5.1.35 to the return value of the functions in *Note gis-mysql-specific-functions::. Thus, those functions may continue to be used to provide the first argument to the functions in this section. * `GeomCollFromWKB(WKB[,SRID])', `GeometryCollectionFromWKB(WKB[,SRID])' Constructs a `GEOMETRYCOLLECTION' value using its WKB representation and SRID. * `GeomFromWKB(WKB[,SRID])', `GeometryFromWKB(WKB[,SRID])' Constructs a geometry value of any type using its WKB representation and SRID. * `LineFromWKB(WKB[,SRID])', `LineStringFromWKB(WKB[,SRID])' Constructs a `LINESTRING' value using its WKB representation and SRID. * `MLineFromWKB(WKB[,SRID])', `MultiLineStringFromWKB(WKB[,SRID])' Constructs a `MULTILINESTRING' value using its WKB representation and SRID. * `MPointFromWKB(WKB[,SRID])', `MultiPointFromWKB(WKB[,SRID])' Constructs a `MULTIPOINT' value using its WKB representation and SRID. * `MPolyFromWKB(WKB[,SRID])', `MultiPolygonFromWKB(WKB[,SRID])' Constructs a `MULTIPOLYGON' value using its WKB representation and SRID. * `PointFromWKB(WKB[,SRID])' Constructs a `POINT' value using its WKB representation and SRID. * `PolyFromWKB(WKB[,SRID])', `PolygonFromWKB(WKB[,SRID])' Constructs a `POLYGON' value using its WKB representation and SRID. The OpenGIS specification also describes optional functions for constructing `Polygon' or `MultiPolygon' values based on the WKB representation of a collection of rings or closed `LineString' values. These values may intersect. MySQL does not implement these functions: * `BdMPolyFromWKB(WKB,SRID)' Constructs a `MultiPolygon' value from a `MultiLineString' value in WKB format containing an arbitrary collection of closed `LineString' values. * `BdPolyFromWKB(WKB,SRID)' Constructs a `Polygon' value from a `MultiLineString' value in WKB format containing an arbitrary collection of closed `LineString' values.  File: manual.info, Node: gis-mysql-specific-functions, Prev: gis-wkb-functions, Up: creating-spatial-values 12.17.4.5 Creating Geometry Values Using MySQL-Specific Functions ................................................................. MySQL provides a set of useful nonstandard functions for creating geometry values. The functions described in this section are MySQL extensions to the OpenGIS specification. As of MySQL 5.1.35, these functions produce geometry objects from either WKB values or geometry objects as arguments. If any argument is not a proper WKB or geometry representation of the proper object type, the return value is `NULL'. Before MySQL 5.1.35, these functions produce *Note `BLOB': blob. values containing WKB representations of geometry values with no SRID from WKB arguments. The WKB value returned from these functions can be converted to geometry arguments by using them as the first argument to functions in the `GeomFromWKB()' function family. For example, as of MySQL 5.1.35, you can insert the geometry return value from `Point()' directly into a `Point' column: INSERT INTO t1 (pt_col) VALUES(Point(1,2)); Prior to MySQL 5.1.35, convert the WKB return value to a `Point' before inserting it: INSERT INTO t1 (pt_col) VALUES(GeomFromWKB(Point(1,2))); * `GeometryCollection(G1,G2,...)' Constructs a `GeometryCollection'. * `LineString(PT1,PT2,...)' Constructs a `LineString' value from a number of `Point' or WKB `Point' arguments. If the number of arguments is less than two, the return value is `NULL'. * `MultiLineString(LS1,LS2,...)' Constructs a `MultiLineString' value using `LineString' or WKB `LineString' arguments. * `MultiPoint(PT1,PT2,...)' Constructs a `MultiPoint' value using `Point' or WKB `Point' arguments. * `MultiPolygon(POLY1,POLY2,...)' Constructs a `MultiPolygon' value from a set of `Polygon' or WKB `Polygon' arguments. * `Point(X,Y)' Constructs a `Point' using its coordinates. * `Polygon(LS1,LS2,...)' Constructs a `Polygon' value from a number of `LineString' or WKB `LineString' arguments. If any argument does not represent a `LinearRing' (that is, not a closed and simple `LineString'), the return value is `NULL'.  File: manual.info, Node: creating-spatial-columns, Next: populating-spatial-columns, Prev: creating-spatial-values, Up: creating-a-spatially-enabled-mysql-database 12.17.4.6 Creating Spatial Columns .................................. MySQL provides a standard way of creating spatial columns for geometry types, for example, with *Note `CREATE TABLE': create-table. or *Note `ALTER TABLE': alter-table. Currently, spatial columns are supported for `MyISAM', `InnoDB', *Note `NDB': mysql-cluster, and `ARCHIVE' tables. See also the annotations about spatial indexes under *Note creating-spatial-indexes::. * Use the *Note `CREATE TABLE': create-table. statement to create a table with a spatial column: CREATE TABLE geom (g GEOMETRY); * Use the *Note `ALTER TABLE': alter-table. statement to add or drop a spatial column to or from an existing table: ALTER TABLE geom ADD pt POINT; ALTER TABLE geom DROP pt;  File: manual.info, Node: populating-spatial-columns, Next: fetching-spatial-data, Prev: creating-spatial-columns, Up: creating-a-spatially-enabled-mysql-database 12.17.4.7 Populating Spatial Columns .................................... After you have created spatial columns, you can populate them with spatial data. Values should be stored in internal geometry format, but you can convert them to that format from either Well-Known Text (WKT) or Well-Known Binary (WKB) format. The following examples demonstrate how to insert geometry values into a table by converting WKT values into internal geometry format: * Perform the conversion directly in the *Note `INSERT': insert. statement: INSERT INTO geom VALUES (GeomFromText('POINT(1 1)')); SET @g = 'POINT(1 1)'; INSERT INTO geom VALUES (GeomFromText(@g)); * Perform the conversion prior to the *Note `INSERT': insert.: SET @g = GeomFromText('POINT(1 1)'); INSERT INTO geom VALUES (@g); The following examples insert more complex geometries into the table: SET @g = 'LINESTRING(0 0,1 1,2 2)'; INSERT INTO geom VALUES (GeomFromText(@g)); SET @g = 'POLYGON((0 0,10 0,10 10,0 10,0 0),(5 5,7 5,7 7,5 7, 5 5))'; INSERT INTO geom VALUES (GeomFromText(@g)); SET @g = 'GEOMETRYCOLLECTION(POINT(1 1),LINESTRING(0 0,1 1,2 2,3 3,4 4))'; INSERT INTO geom VALUES (GeomFromText(@g)); The preceding examples all use `GeomFromText()' to create geometry values. You can also use type-specific functions: SET @g = 'POINT(1 1)'; INSERT INTO geom VALUES (PointFromText(@g)); SET @g = 'LINESTRING(0 0,1 1,2 2)'; INSERT INTO geom VALUES (LineStringFromText(@g)); SET @g = 'POLYGON((0 0,10 0,10 10,0 10,0 0),(5 5,7 5,7 7,5 7, 5 5))'; INSERT INTO geom VALUES (PolygonFromText(@g)); SET @g = 'GEOMETRYCOLLECTION(POINT(1 1),LINESTRING(0 0,1 1,2 2,3 3,4 4))'; INSERT INTO geom VALUES (GeomCollFromText(@g)); Note that if a client application program wants to use WKB representations of geometry values, it is responsible for sending correctly formed WKB in queries to the server. However, there are several ways of satisfying this requirement. For example: * Inserting a `POINT(1 1)' value with hex literal syntax: mysql> INSERT INTO geom VALUES -> (GeomFromWKB(0x0101000000000000000000F03F000000000000F03F)); * An ODBC application can send a WKB representation, binding it to a placeholder using an argument of *Note `BLOB': blob. type: INSERT INTO geom VALUES (GeomFromWKB(?)) Other programming interfaces may support a similar placeholder mechanism. * In a C program, you can escape a binary value using *Note `mysql_real_escape_string()': mysql-real-escape-string. and include the result in a query string that is sent to the server. See *Note mysql-real-escape-string::.  File: manual.info, Node: fetching-spatial-data, Prev: populating-spatial-columns, Up: creating-a-spatially-enabled-mysql-database 12.17.4.8 Fetching Spatial Data ............................... Geometry values stored in a table can be fetched in internal format. You can also convert them into WKT or WKB format. * Fetching spatial data in internal format: Fetching geometry values using internal format can be useful in table-to-table transfers: CREATE TABLE geom2 (g GEOMETRY) SELECT g FROM geom; * Fetching spatial data in WKT format: The `AsText()' function converts a geometry from internal format into a WKT string. SELECT AsText(g) FROM geom; * Fetching spatial data in WKB format: The `AsBinary()' function converts a geometry from internal format into a *Note `BLOB': blob. containing the WKB value. SELECT AsBinary(g) FROM geom;  File: manual.info, Node: spatial-analysis-functions, Next: optimizing-spatial-analysis, Prev: creating-a-spatially-enabled-mysql-database, Up: spatial-extensions 12.17.5 Spatial Analysis Functions ---------------------------------- * Menu: * functions-to-convert-geometries-between-formats:: Geometry Format Conversion Functions * geometry-property-functions:: `Geometry' Functions * functions-that-create-new-geometries-from-existing-ones:: Functions That Create New Geometries from Existing Ones * functions-for-testing-spatial-relations-between-geometric-objects:: Functions for Testing Spatial Relations Between Geometric Objects After populating spatial columns with values, you are ready to query and analyze them. MySQL provides a set of functions to perform various operations on spatial data. These functions can be grouped into four major categories according to the type of operation they perform: * Functions that convert geometries between various formats * Functions that provide access to qualitative or quantitative properties of a geometry * Functions that describe relations between two geometries * Functions that create new geometries from existing ones Spatial analysis functions can be used in many contexts, such as: * Any interactive SQL program, such as *Note `mysql': mysql. * Application programs written in any language that supports a MySQL client API  File: manual.info, Node: functions-to-convert-geometries-between-formats, Next: geometry-property-functions, Prev: spatial-analysis-functions, Up: spatial-analysis-functions 12.17.5.1 Geometry Format Conversion Functions .............................................. MySQL supports the following functions for converting geometry values between internal format and either WKT or WKB format: * `AsBinary(G)', `AsWKB(G)' Converts a value in internal geometry format to its WKB representation and returns the binary result. SELECT AsBinary(g) FROM geom; * `AsText(G)', `AsWKT(G)' Converts a value in internal geometry format to its WKT representation and returns the string result. mysql> SET @g = 'LineString(1 1,2 2,3 3)'; mysql> SELECT AsText(GeomFromText(@g)); +--------------------------+ | AsText(GeomFromText(@g)) | +--------------------------+ | LINESTRING(1 1,2 2,3 3) | +--------------------------+ * `GeomFromText(WKT[,SRID])' Converts a string value from its WKT representation into internal geometry format and returns the result. A number of type-specific functions are also supported, such as `PointFromText()' and `LineFromText()'. See *Note gis-wkt-functions::. * `GeomFromWKB(WKB[,SRID])' Converts a binary value from its WKB representation into internal geometry format and returns the result. A number of type-specific functions are also supported, such as `PointFromWKB()' and `LineFromWKB()'. See *Note gis-wkb-functions::.  File: manual.info, Node: geometry-property-functions, Next: functions-that-create-new-geometries-from-existing-ones, Prev: functions-to-convert-geometries-between-formats, Up: spatial-analysis-functions 12.17.5.2 `Geometry' Functions .............................. * Menu: * general-geometry-property-functions:: General Geometry Functions * point-property-functions:: `Point' Functions * linestring-property-functions:: `LineString' Functions * multilinestring-property-functions:: `MultiLineString' Functions * polygon-property-functions:: `Polygon' Functions * multipolygon-property-functions:: `MultiPolygon' Functions * geometrycollection-property-functions:: `GeometryCollection' Functions Each function that belongs to this group takes a geometry value as its argument and returns some quantitative or qualitative property of the geometry. Some functions restrict their argument type. Such functions return `NULL' if the argument is of an incorrect geometry type. For example, `Area()' returns `NULL' if the object type is neither `Polygon' nor `MultiPolygon'.  File: manual.info, Node: general-geometry-property-functions, Next: point-property-functions, Prev: geometry-property-functions, Up: geometry-property-functions 12.17.5.3 General Geometry Functions .................................... The functions listed in this section do not restrict their argument and accept a geometry value of any type. * `Dimension(G)' Returns the inherent dimension of the geometry value G. The result can be -1, 0, 1, or 2. The meaning of these values is given in *Note gis-class-geometry::. mysql> SELECT Dimension(GeomFromText('LineString(1 1,2 2)')); +------------------------------------------------+ | Dimension(GeomFromText('LineString(1 1,2 2)')) | +------------------------------------------------+ | 1 | +------------------------------------------------+ * `Envelope(G)' Returns the Minimum Bounding Rectangle (MBR) for the geometry value G. The result is returned as a `Polygon' value. The polygon is defined by the corner points of the bounding box: POLYGON((MINX MINY, MAXX MINY, MAXX MAXY, MINX MAXY, MINX MINY)) mysql> SELECT AsText(Envelope(GeomFromText('LineString(1 1,2 2)'))); +-------------------------------------------------------+ | AsText(Envelope(GeomFromText('LineString(1 1,2 2)'))) | +-------------------------------------------------------+ | POLYGON((1 1,2 1,2 2,1 2,1 1)) | +-------------------------------------------------------+ * `GeometryType(G)' Returns as a string the name of the geometry type of which the geometry instance G is a member. The name corresponds to one of the instantiable `Geometry' subclasses. mysql> SELECT GeometryType(GeomFromText('POINT(1 1)')); +------------------------------------------+ | GeometryType(GeomFromText('POINT(1 1)')) | +------------------------------------------+ | POINT | +------------------------------------------+ * `SRID(G)' Returns an integer indicating the Spatial Reference System ID for the geometry value G. In MySQL, the SRID value is just an integer associated with the geometry value. All calculations are done assuming Euclidean (planar) geometry. mysql> SELECT SRID(GeomFromText('LineString(1 1,2 2)',101)); +-----------------------------------------------+ | SRID(GeomFromText('LineString(1 1,2 2)',101)) | +-----------------------------------------------+ | 101 | +-----------------------------------------------+ The OpenGIS specification also defines the following functions, which MySQL does not implement: * `Boundary(G)' Returns a geometry that is the closure of the combinatorial boundary of the geometry value G. * `IsEmpty(G)' Returns 1 if the geometry value G is the empty geometry, 0 if it is not empty, and -1 if the argument is `NULL'. If the geometry is empty, it represents the empty point set. * `IsSimple(G)' Currently, this function is a placeholder and should not be used. If implemented, its behavior will be as described in the next paragraph. Returns 1 if the geometry value G has no anomalous geometric points, such as self-intersection or self-tangency. `IsSimple()' returns 0 if the argument is not simple, and -1 if it is `NULL'. The description of each instantiable geometric class given earlier in the chapter includes the specific conditions that cause an instance of that class to be classified as not simple. (See *Note gis-geometry-class-hierarchy::.)  File: manual.info, Node: point-property-functions, Next: linestring-property-functions, Prev: general-geometry-property-functions, Up: geometry-property-functions 12.17.5.4 `Point' Functions ........................... A `Point' consists of X and Y coordinates, which may be obtained using the following functions: * `X(P)' Returns the X-coordinate value for the `Point' object P as a double-precision number. mysql> SELECT X(POINT(56.7, 53.34)); +-----------------------+ | X(POINT(56.7, 53.34)) | +-----------------------+ | 56.7 | +-----------------------+ * `Y(P)' Returns the Y-coordinate value for the `Point' object P as a double-precision number. mysql> SELECT Y(POINT(56.7, 53.34)); +-----------------------+ | Y(POINT(56.7, 53.34)) | +-----------------------+ | 53.34 | +-----------------------+  File: manual.info, Node: linestring-property-functions, Next: multilinestring-property-functions, Prev: point-property-functions, Up: geometry-property-functions 12.17.5.5 `LineString' Functions ................................ A `LineString' consists of `Point' values. You can extract particular points of a `LineString', count the number of points that it contains, or obtain its length. * `EndPoint(LS)' Returns the `Point' that is the endpoint of the `LineString' value LS. mysql> SET @ls = 'LineString(1 1,2 2,3 3)'; mysql> SELECT AsText(EndPoint(GeomFromText(@ls))); +-------------------------------------+ | AsText(EndPoint(GeomFromText(@ls))) | +-------------------------------------+ | POINT(3 3) | +-------------------------------------+ * `GLength(LS)' Returns as a double-precision number the length of the `LineString' value LS in its associated spatial reference. mysql> SET @ls = 'LineString(1 1,2 2,3 3)'; mysql> SELECT GLength(GeomFromText(@ls)); +----------------------------+ | GLength(GeomFromText(@ls)) | +----------------------------+ | 2.8284271247462 | +----------------------------+ `GLength()' is a nonstandard name. It corresponds to the OpenGIS `Length()' function. * `NumPoints(LS)' Returns the number of `Point' objects in the `LineString' value LS. mysql> SET @ls = 'LineString(1 1,2 2,3 3)'; mysql> SELECT NumPoints(GeomFromText(@ls)); +------------------------------+ | NumPoints(GeomFromText(@ls)) | +------------------------------+ | 3 | +------------------------------+ * `PointN(LS,N)' Returns the N-th `Point' in the `Linestring' value LS. Points are numbered beginning with 1. mysql> SET @ls = 'LineString(1 1,2 2,3 3)'; mysql> SELECT AsText(PointN(GeomFromText(@ls),2)); +-------------------------------------+ | AsText(PointN(GeomFromText(@ls),2)) | +-------------------------------------+ | POINT(2 2) | +-------------------------------------+ * `StartPoint(LS)' Returns the `Point' that is the start point of the `LineString' value LS. mysql> SET @ls = 'LineString(1 1,2 2,3 3)'; mysql> SELECT AsText(StartPoint(GeomFromText(@ls))); +---------------------------------------+ | AsText(StartPoint(GeomFromText(@ls))) | +---------------------------------------+ | POINT(1 1) | +---------------------------------------+ The OpenGIS specification also defines the following function, which MySQL does not implement: * `IsRing(LS)' Returns 1 if the `LineString' value LS is closed (that is, its `StartPoint()' and `EndPoint()' values are the same) and is simple (does not pass through the same point more than once). Returns 0 if LS is not a ring, and -1 if it is `NULL'.  File: manual.info, Node: multilinestring-property-functions, Next: polygon-property-functions, Prev: linestring-property-functions, Up: geometry-property-functions 12.17.5.6 `MultiLineString' Functions ..................................... These functions return properties of `MultiLineString' values. * `GLength(MLS)' Returns as a double-precision number the length of the `MultiLineString' value MLS. The length of MLS is equal to the sum of the lengths of its elements. mysql> SET @mls = 'MultiLineString((1 1,2 2,3 3),(4 4,5 5))'; mysql> SELECT GLength(GeomFromText(@mls)); +-----------------------------+ | GLength(GeomFromText(@mls)) | +-----------------------------+ | 4.2426406871193 | +-----------------------------+ `GLength()' is a nonstandard name. It corresponds to the OpenGIS `Length()' function. * `IsClosed(MLS)' Returns 1 if the `MultiLineString' value MLS is closed (that is, the `StartPoint()' and `EndPoint()' values are the same for each `LineString' in MLS). Returns 0 if MLS is not closed, and -1 if it is `NULL'. mysql> SET @mls = 'MultiLineString((1 1,2 2,3 3),(4 4,5 5))'; mysql> SELECT IsClosed(GeomFromText(@mls)); +------------------------------+ | IsClosed(GeomFromText(@mls)) | +------------------------------+ | 0 | +------------------------------+  File: manual.info, Node: polygon-property-functions, Next: multipolygon-property-functions, Prev: multilinestring-property-functions, Up: geometry-property-functions 12.17.5.7 `Polygon' Functions ............................. These functions return properties of `Polygon' values. * `Area(POLY)' Returns as a double-precision number the area of the `Polygon' value POLY, as measured in its spatial reference system. mysql> SET @poly = 'Polygon((0 0,0 3,3 0,0 0),(1 1,1 2,2 1,1 1))'; mysql> SELECT Area(GeomFromText(@poly)); +---------------------------+ | Area(GeomFromText(@poly)) | +---------------------------+ | 4 | +---------------------------+ * `ExteriorRing(POLY)' Returns the exterior ring of the `Polygon' value POLY as a `LineString'. mysql> SET @poly = -> 'Polygon((0 0,0 3,3 3,3 0,0 0),(1 1,1 2,2 2,2 1,1 1))'; mysql> SELECT AsText(ExteriorRing(GeomFromText(@poly))); +-------------------------------------------+ | AsText(ExteriorRing(GeomFromText(@poly))) | +-------------------------------------------+ | LINESTRING(0 0,0 3,3 3,3 0,0 0) | +-------------------------------------------+ * `InteriorRingN(POLY,N)' Returns the N-th interior ring for the `Polygon' value POLY as a `LineString'. Rings are numbered beginning with 1. mysql> SET @poly = -> 'Polygon((0 0,0 3,3 3,3 0,0 0),(1 1,1 2,2 2,2 1,1 1))'; mysql> SELECT AsText(InteriorRingN(GeomFromText(@poly),1)); +----------------------------------------------+ | AsText(InteriorRingN(GeomFromText(@poly),1)) | +----------------------------------------------+ | LINESTRING(1 1,1 2,2 2,2 1,1 1) | +----------------------------------------------+ * `NumInteriorRings(POLY)' Returns the number of interior rings in the `Polygon' value POLY. mysql> SET @poly = -> 'Polygon((0 0,0 3,3 3,3 0,0 0),(1 1,1 2,2 2,2 1,1 1))'; mysql> SELECT NumInteriorRings(GeomFromText(@poly)); +---------------------------------------+ | NumInteriorRings(GeomFromText(@poly)) | +---------------------------------------+ | 1 | +---------------------------------------+  File: manual.info, Node: multipolygon-property-functions, Next: geometrycollection-property-functions, Prev: polygon-property-functions, Up: geometry-property-functions 12.17.5.8 `MultiPolygon' Functions .................................. These functions return properties of `MultiPolygon' values. * `Area(MPOLY)' Returns as a double-precision number the area of the `MultiPolygon' value MPOLY, as measured in its spatial reference system. mysql> SET @mpoly = -> 'MultiPolygon(((0 0,0 3,3 3,3 0,0 0),(1 1,1 2,2 2,2 1,1 1)))'; mysql> SELECT Area(GeomFromText(@mpoly)); +----------------------------+ | Area(GeomFromText(@mpoly)) | +----------------------------+ | 8 | +----------------------------+ The OpenGIS specification also defines the following functions, which MySQL does not implement: * `Centroid(MPOLY)' Returns the mathematical centroid for the `MultiPolygon' value MPOLY as a `Point'. The result is not guaranteed to be on the `MultiPolygon'. * `PointOnSurface(MPOLY)' Returns a `Point' value that is guaranteed to be on the `MultiPolygon' value MPOLY.  File: manual.info, Node: geometrycollection-property-functions, Prev: multipolygon-property-functions, Up: geometry-property-functions 12.17.5.9 `GeometryCollection' Functions ........................................ These functions return properties of `GeometryCollection' values. * `GeometryN(GC,N)' Returns the N-th geometry in the `GeometryCollection' value GC. Geometries are numbered beginning with 1. mysql> SET @gc = 'GeometryCollection(Point(1 1),LineString(2 2, 3 3))'; mysql> SELECT AsText(GeometryN(GeomFromText(@gc),1)); +----------------------------------------+ | AsText(GeometryN(GeomFromText(@gc),1)) | +----------------------------------------+ | POINT(1 1) | +----------------------------------------+ * `NumGeometries(GC)' Returns the number of geometries in the `GeometryCollection' value GC. mysql> SET @gc = 'GeometryCollection(Point(1 1),LineString(2 2, 3 3))'; mysql> SELECT NumGeometries(GeomFromText(@gc)); +----------------------------------+ | NumGeometries(GeomFromText(@gc)) | +----------------------------------+ | 2 | +----------------------------------+  File: manual.info, Node: functions-that-create-new-geometries-from-existing-ones, Next: functions-for-testing-spatial-relations-between-geometric-objects, Prev: geometry-property-functions, Up: spatial-analysis-functions 12.17.5.10 Functions That Create New Geometries from Existing Ones .................................................................. * Menu: * functions-that-produce-new-geometries:: Geometry Functions That Produce New Geometries * spatial-operators:: Spatial Operators The following sections describe functions that take geometry values as arguments and return new geometry values.  File: manual.info, Node: functions-that-produce-new-geometries, Next: spatial-operators, Prev: functions-that-create-new-geometries-from-existing-ones, Up: functions-that-create-new-geometries-from-existing-ones 12.17.5.11 Geometry Functions That Produce New Geometries ......................................................... *Note geometry-property-functions::, discusses several functions that construct new geometries from existing ones. See that section for descriptions of these functions: * `Envelope(G)' * `StartPoint(LS)' * `EndPoint(LS)' * `PointN(LS,N)' * `ExteriorRing(POLY)' * `InteriorRingN(POLY,N)' * `GeometryN(GC,N)'  File: manual.info, Node: spatial-operators, Prev: functions-that-produce-new-geometries, Up: functions-that-create-new-geometries-from-existing-ones 12.17.5.12 Spatial Operators ............................ OpenGIS proposes a number of other functions that can produce geometries. They are designed to implement spatial operators. These functions are not implemented in MySQL. * `Buffer(G,D)' Returns a geometry that represents all points whose distance from the geometry value G is less than or equal to a distance of D. * `ConvexHull(G)' Returns a geometry that represents the convex hull of the geometry value G. * `Difference(G1,G2)' Returns a geometry that represents the point set difference of the geometry value G1 with G2. * `Intersection(G1,G2)' Returns a geometry that represents the point set intersection of the geometry values G1 with G2. * `SymDifference(G1,G2)' Returns a geometry that represents the point set symmetric difference of the geometry value G1 with G2. * `Union(G1,G2)' Returns a geometry that represents the point set union of the geometry values G1 and G2.  File: manual.info, Node: functions-for-testing-spatial-relations-between-geometric-objects, Prev: functions-that-create-new-geometries-from-existing-ones, Up: spatial-analysis-functions 12.17.5.13 Functions for Testing Spatial Relations Between Geometric Objects ............................................................................ * Menu: * relations-on-geometry-mbr:: Relations on Geometry Minimal Bounding Rectangles (MBRs) * functions-that-test-spatial-relationships-between-geometries:: Functions That Test Spatial Relationships Between Geometries The functions described in these sections take two geometries as input parameters and return a qualitative or quantitative relation between them.  File: manual.info, Node: relations-on-geometry-mbr, Next: functions-that-test-spatial-relationships-between-geometries, Prev: functions-for-testing-spatial-relations-between-geometric-objects, Up: functions-for-testing-spatial-relations-between-geometric-objects 12.17.5.14 Relations on Geometry Minimal Bounding Rectangles (MBRs) ................................................................... MySQL provides several functions that test relations between minimal bounding rectangles of two geometries `g1' and `g2'. The return values 1 and 0 indicate true and false, respectively. * `MBRContains(G1,G2)' Returns 1 or 0 to indicate whether the Minimum Bounding Rectangle of G1 contains the Minimum Bounding Rectangle of G2. This tests the opposite relationship as `MBRWithin()'. mysql> SET @g1 = GeomFromText('Polygon((0 0,0 3,3 3,3 0,0 0))'); mysql> SET @g2 = GeomFromText('Point(1 1)'); mysql> SELECT MBRContains(@g1,@g2), MBRContains(@g2,@g1); ----------------------+----------------------+ | MBRContains(@g1,@g2) | MBRContains(@g2,@g1) | +----------------------+----------------------+ | 1 | 0 | +----------------------+----------------------+ * `MBRDisjoint(G1,G2)' Returns 1 or 0 to indicate whether the Minimum Bounding Rectangles of the two geometries G1 and G2 are disjoint (do not intersect). * `MBREqual(G1,G2)' Returns 1 or 0 to indicate whether the Minimum Bounding Rectangles of the two geometries G1 and G2 are the same. * `MBRIntersects(G1,G2)' Returns 1 or 0 to indicate whether the Minimum Bounding Rectangles of the two geometries G1 and G2 intersect. * `MBROverlaps(G1,G2)' Returns 1 or 0 to indicate whether the Minimum Bounding Rectangles of the two geometries G1 and G2 overlap. The term _spatially overlaps_ is used if two geometries intersect and their intersection results in a geometry of the same dimension but not equal to either of the given geometries. * `MBRTouches(G1,G2)' Returns 1 or 0 to indicate whether the Minimum Bounding Rectangles of the two geometries G1 and G2 touch. Two geometries _spatially touch_ if the interiors of the geometries do not intersect, but the boundary of one of the geometries intersects either the boundary or the interior of the other. * `MBRWithin(G1,G2)' Returns 1 or 0 to indicate whether the Minimum Bounding Rectangle of G1 is within the Minimum Bounding Rectangle of G2. This tests the opposite relationship as `MBRContains()'. mysql> SET @g1 = GeomFromText('Polygon((0 0,0 3,3 3,3 0,0 0))'); mysql> SET @g2 = GeomFromText('Polygon((0 0,0 5,5 5,5 0,0 0))'); mysql> SELECT MBRWithin(@g1,@g2), MBRWithin(@g2,@g1); +--------------------+--------------------+ | MBRWithin(@g1,@g2) | MBRWithin(@g2,@g1) | +--------------------+--------------------+ | 1 | 0 | +--------------------+--------------------+  File: manual.info, Node: functions-that-test-spatial-relationships-between-geometries, Prev: relations-on-geometry-mbr, Up: functions-for-testing-spatial-relations-between-geometric-objects 12.17.5.15 Functions That Test Spatial Relationships Between Geometries ....................................................................... The OpenGIS specification defines the following functions. They test the relationship between two geometry values `g1' and `g2'. The return values 1 and 0 indicate true and false, respectively. *Note*: Currently, MySQL does not implement these functions according to the specification. Those that are implemented return the same result as the corresponding MBR-based functions. * `Contains(G1,G2)' Returns 1 or 0 to indicate whether G1 completely contains G2. This tests the opposite relationship as `Within()'. * `Crosses(G1,G2)' Returns 1 if G1 spatially crosses G2. Returns `NULL' if `g1' is a `Polygon' or a `MultiPolygon', or if G2 is a `Point' or a `MultiPoint'. Otherwise, returns 0. The term _spatially crosses_ denotes a spatial relation between two given geometries that has the following properties: * The two geometries intersect * Their intersection results in a geometry that has a dimension that is one less than the maximum dimension of the two given geometries * Their intersection is not equal to either of the two given geometries * `Disjoint(G1,G2)' Returns 1 or 0 to indicate whether G1 is spatially disjoint from (does not intersect) G2. * `Equals(G1,G2)' Returns 1 or 0 to indicate whether G1 is spatially equal to G2. * `Intersects(G1,G2)' Returns 1 or 0 to indicate whether G1 spatially intersects G2. * `Overlaps(G1,G2)' Returns 1 or 0 to indicate whether G1 spatially overlaps G2. The term _spatially overlaps_ is used if two geometries intersect and their intersection results in a geometry of the same dimension but not equal to either of the given geometries. * `Touches(G1,G2)' Returns 1 or 0 to indicate whether G1 spatially touches G2. Two geometries _spatially touch_ if the interiors of the geometries do not intersect, but the boundary of one of the geometries intersects either the boundary or the interior of the other. * `Within(G1,G2)' Returns 1 or 0 to indicate whether G1 is spatially within G2. This tests the opposite relationship as `Contains()'.  File: manual.info, Node: optimizing-spatial-analysis, Next: mysql-gis-conformance-and-compatibility, Prev: spatial-analysis-functions, Up: spatial-extensions 12.17.6 Optimizing Spatial Analysis ----------------------------------- * Menu: * creating-spatial-indexes:: Creating Spatial Indexes * using-a-spatial-index:: Using a Spatial Index For *Note `MyISAM': myisam-storage-engine. tables, Search operations in nonspatial databases can be optimized using `SPATIAL' indexes. This is true for spatial databases as well. With the help of a great variety of multi-dimensional indexing methods that have previously been designed, it is possible to optimize spatial searches. The most typical of these are: * Point queries that search for all objects that contain a given point * Region queries that search for all objects that overlap a given region MySQL uses *R-Trees with quadratic splitting* for `SPATIAL' indexes on spatial columns. A `SPATIAL' index is built using the MBR of a geometry. For most geometries, the MBR is a minimum rectangle that surrounds the geometries. For a horizontal or a vertical linestring, the MBR is a rectangle degenerated into the linestring. For a point, the MBR is a rectangle degenerated into the point. It is also possible to create normal indexes on spatial columns. In a non-`SPATIAL' index, you must declare a prefix for any spatial column except for `POINT' columns. `MyISAM' supports both `SPATIAL' and non-`SPATIAL' indexes. Other storage engines support non-`SPATIAL' indexes, as described in *Note create-index::.  File: manual.info, Node: creating-spatial-indexes, Next: using-a-spatial-index, Prev: optimizing-spatial-analysis, Up: optimizing-spatial-analysis 12.17.6.1 Creating Spatial Indexes .................................. For *Note `MyISAM': myisam-storage-engine. tables, MySQL can create spatial indexes using syntax similar to that for creating regular indexes, but extended with the `SPATIAL' keyword. Currently, columns in spatial indexes must be declared `NOT NULL'. The following examples demonstrate how to create spatial indexes: * With *Note `CREATE TABLE': create-table.: CREATE TABLE geom (g GEOMETRY NOT NULL, SPATIAL INDEX(g)) ENGINE=MyISAM; * With *Note `ALTER TABLE': alter-table.: ALTER TABLE geom ADD SPATIAL INDEX(g); * With *Note `CREATE INDEX': create-index.: CREATE SPATIAL INDEX sp_index ON geom (g); For `MyISAM' tables, `SPATIAL INDEX' creates an R-tree index. For storage engines that support nonspatial indexing of spatial columns, the engine creates a B-tree index. A B-tree index on spatial values will be useful for exact-value lookups, but not for range scans. For more information on indexing spatial columns, see *Note create-index::. To drop spatial indexes, use *Note `ALTER TABLE': alter-table. or *Note `DROP INDEX': drop-index.: * With *Note `ALTER TABLE': alter-table.: ALTER TABLE geom DROP INDEX g; * With *Note `DROP INDEX': drop-index.: DROP INDEX sp_index ON geom; Example: Suppose that a table `geom' contains more than 32,000 geometries, which are stored in the column `g' of type `GEOMETRY'. The table also has an `AUTO_INCREMENT' column `fid' for storing object ID values. mysql> DESCRIBE geom; +-------+----------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +-------+----------+------+-----+---------+----------------+ | fid | int(11) | | PRI | NULL | auto_increment | | g | geometry | | | | | +-------+----------+------+-----+---------+----------------+ 2 rows in set (0.00 sec) mysql> SELECT COUNT(*) FROM geom; +----------+ | count(*) | +----------+ | 32376 | +----------+ 1 row in set (0.00 sec) To add a spatial index on the column `g', use this statement: mysql> ALTER TABLE geom ADD SPATIAL INDEX(g); Query OK, 32376 rows affected (4.05 sec) Records: 32376 Duplicates: 0 Warnings: 0  File: manual.info, Node: using-a-spatial-index, Prev: creating-spatial-indexes, Up: optimizing-spatial-analysis 12.17.6.2 Using a Spatial Index ............................... The optimizer investigates whether available spatial indexes can be involved in the search for queries that use a function such as `MBRContains()' or `MBRWithin()' in the `WHERE' clause. The following query finds all objects that are in the given rectangle: mysql> SET @poly = -> 'Polygon((30000 15000, 31000 15000, 31000 16000, 30000 16000, 30000 15000))'; mysql> SELECT fid,AsText(g) FROM geom WHERE -> MBRContains(GeomFromText(@poly),g); +-----+---------------------------------------------------------------+ | fid | AsText(g) | +-----+---------------------------------------------------------------+ | 21 | LINESTRING(30350.4 15828.8,30350.6 15845,30333.8 15845,30 ... | | 22 | LINESTRING(30350.6 15871.4,30350.6 15887.8,30334 15887.8, ... | | 23 | LINESTRING(30350.6 15914.2,30350.6 15930.4,30334 15930.4, ... | | 24 | LINESTRING(30290.2 15823,30290.2 15839.4,30273.4 15839.4, ... | | 25 | LINESTRING(30291.4 15866.2,30291.6 15882.4,30274.8 15882. ... | | 26 | LINESTRING(30291.6 15918.2,30291.6 15934.4,30275 15934.4, ... | | 249 | LINESTRING(30337.8 15938.6,30337.8 15946.8,30320.4 15946. ... | | 1 | LINESTRING(30250.4 15129.2,30248.8 15138.4,30238.2 15136. ... | | 2 | LINESTRING(30220.2 15122.8,30217.2 15137.8,30207.6 15136, ... | | 3 | LINESTRING(30179 15114.4,30176.6 15129.4,30167 15128,3016 ... | | 4 | LINESTRING(30155.2 15121.4,30140.4 15118.6,30142 15109,30 ... | | 5 | LINESTRING(30192.4 15085,30177.6 15082.2,30179.2 15072.4, ... | | 6 | LINESTRING(30244 15087,30229 15086.2,30229.4 15076.4,3024 ... | | 7 | LINESTRING(30200.6 15059.4,30185.6 15058.6,30186 15048.8, ... | | 10 | LINESTRING(30179.6 15017.8,30181 15002.8,30190.8 15003.6, ... | | 11 | LINESTRING(30154.2 15000.4,30168.6 15004.8,30166 15014.2, ... | | 13 | LINESTRING(30105 15065.8,30108.4 15050.8,30118 15053,3011 ... | | 154 | LINESTRING(30276.2 15143.8,30261.4 15141,30263 15131.4,30 ... | | 155 | LINESTRING(30269.8 15084,30269.4 15093.4,30258.6 15093,30 ... | | 157 | LINESTRING(30128.2 15011,30113.2 15010.2,30113.6 15000.4, ... | +-----+---------------------------------------------------------------+ 20 rows in set (0.00 sec) Use *Note `EXPLAIN': explain. to check the way this query is executed: mysql> SET @poly = -> 'Polygon((30000 15000, 31000 15000, 31000 16000, 30000 16000, 30000 15000))'; mysql> EXPLAIN SELECT fid,AsText(g) FROM geom WHERE -> MBRContains(GeomFromText(@poly),g)\G *************************** 1. row *************************** id: 1 select_type: SIMPLE table: geom type: range possible_keys: g key: g key_len: 32 ref: NULL rows: 50 Extra: Using where 1 row in set (0.00 sec) Check what would happen without a spatial index: mysql> SET @poly = -> 'Polygon((30000 15000, 31000 15000, 31000 16000, 30000 16000, 30000 15000))'; mysql> EXPLAIN SELECT fid,AsText(g) FROM g IGNORE INDEX (g) WHERE -> MBRContains(GeomFromText(@poly),g)\G *************************** 1. row *************************** id: 1 select_type: SIMPLE table: geom type: ALL possible_keys: NULL key: NULL key_len: NULL ref: NULL rows: 32376 Extra: Using where 1 row in set (0.00 sec) Executing the *Note `SELECT': select. statement without the spatial index yields the same result but causes the execution time to rise from 0.00 seconds to 0.46 seconds: mysql> SET @poly = -> 'Polygon((30000 15000, 31000 15000, 31000 16000, 30000 16000, 30000 15000))'; mysql> SELECT fid,AsText(g) FROM geom IGNORE INDEX (g) WHERE -> MBRContains(GeomFromText(@poly),g); +-----+---------------------------------------------------------------+ | fid | AsText(g) | +-----+---------------------------------------------------------------+ | 1 | LINESTRING(30250.4 15129.2,30248.8 15138.4,30238.2 15136. ... | | 2 | LINESTRING(30220.2 15122.8,30217.2 15137.8,30207.6 15136, ... | | 3 | LINESTRING(30179 15114.4,30176.6 15129.4,30167 15128,3016 ... | | 4 | LINESTRING(30155.2 15121.4,30140.4 15118.6,30142 15109,30 ... | | 5 | LINESTRING(30192.4 15085,30177.6 15082.2,30179.2 15072.4, ... | | 6 | LINESTRING(30244 15087,30229 15086.2,30229.4 15076.4,3024 ... | | 7 | LINESTRING(30200.6 15059.4,30185.6 15058.6,30186 15048.8, ... | | 10 | LINESTRING(30179.6 15017.8,30181 15002.8,30190.8 15003.6, ... | | 11 | LINESTRING(30154.2 15000.4,30168.6 15004.8,30166 15014.2, ... | | 13 | LINESTRING(30105 15065.8,30108.4 15050.8,30118 15053,3011 ... | | 21 | LINESTRING(30350.4 15828.8,30350.6 15845,30333.8 15845,30 ... | | 22 | LINESTRING(30350.6 15871.4,30350.6 15887.8,30334 15887.8, ... | | 23 | LINESTRING(30350.6 15914.2,30350.6 15930.4,30334 15930.4, ... | | 24 | LINESTRING(30290.2 15823,30290.2 15839.4,30273.4 15839.4, ... | | 25 | LINESTRING(30291.4 15866.2,30291.6 15882.4,30274.8 15882. ... | | 26 | LINESTRING(30291.6 15918.2,30291.6 15934.4,30275 15934.4, ... | | 154 | LINESTRING(30276.2 15143.8,30261.4 15141,30263 15131.4,30 ... | | 155 | LINESTRING(30269.8 15084,30269.4 15093.4,30258.6 15093,30 ... | | 157 | LINESTRING(30128.2 15011,30113.2 15010.2,30113.6 15000.4, ... | | 249 | LINESTRING(30337.8 15938.6,30337.8 15946.8,30320.4 15946. ... | +-----+---------------------------------------------------------------+ 20 rows in set (0.46 sec)  File: manual.info, Node: mysql-gis-conformance-and-compatibility, Prev: optimizing-spatial-analysis, Up: spatial-extensions 12.17.7 MySQL Conformance and Compatibility ------------------------------------------- MySQL does not yet implement the following GIS features: * Additional Metadata Views OpenGIS specifications propose several additional metadata views. For example, a system view named `GEOMETRY_COLUMNS' contains a description of geometry columns, one row for each geometry column in the database. * The OpenGIS function `Length()' on `LineString' and `MultiLineString' currently should be called in MySQL as `GLength()' The problem is that there is an existing SQL function `Length()' that calculates the length of string values, and sometimes it is not possible to distinguish whether the function is called in a textual or spatial context. We need either to solve this somehow, or decide on another function name.  File: manual.info, Node: precision-math, Prev: spatial-extensions, Up: functions 12.18 Precision Math ==================== * Menu: * precision-math-numbers:: Types of Numeric Values * precision-math-decimal-changes:: `DECIMAL' Data Type Changes * precision-math-expressions:: Expression Handling * precision-math-rounding:: Rounding Behavior * precision-math-examples:: Precision Math Examples MySQL 5.1 provides support for precision math: numeric value handling that results in extremely accurate results and a high degree control over invalid values. Precision math is based on these two features: * SQL modes that control how strict the server is about accepting or rejecting invalid data. * The MySQL library for fixed-point arithmetic. These features have several implications for numeric operations and provide a high degree of compliance with standard SQL: * *Precise calculations*: For exact-value numbers, calculations do not introduce floating-point errors. Instead, exact precision is used. For example, MySQL treats a number such as `.0001' as an exact value rather than as an approximation, and summing it 10,000 times produces a result of exactly `1', not a value that is merely `close' to 1. * *Well-defined rounding behavior*: For exact-value numbers, the result of `ROUND()' depends on its argument, not on environmental factors such as how the underlying C library works. * *Platform independence*: Operations on exact numeric values are the same across different platforms such as Windows and Unix. * *Control over handling of invalid values*: Overflow and division by zero are detectable and can be treated as errors. For example, you can treat a value that is too large for a column as an error rather than having the value truncated to lie within the range of the column's data type. Similarly, you can treat division by zero as an error rather than as an operation that produces a result of `NULL'. The choice of which approach to take is determined by the setting of the server SQL mode. The following discussion covers several aspects of how precision math works, including possible incompatibilities with older applications. At the end, some examples are given that demonstrate how MySQL 5.1 handles numeric operations precisely. For information about controlling the SQL mode, see *Note server-sql-mode::.  File: manual.info, Node: precision-math-numbers, Next: precision-math-decimal-changes, Prev: precision-math, Up: precision-math 12.18.1 Types of Numeric Values ------------------------------- The scope of precision math for exact-value operations includes the exact-value data types (*Note `DECIMAL': numeric-types. and integer types) and exact-value numeric literals. Approximate-value data types and numeric literals are handled as floating-point numbers. Exact-value numeric literals have an integer part or fractional part, or both. They may be signed. Examples: `1', `.2', `3.4', `-5', `-6.78', `+9.10'. Approximate-value numeric literals are represented in scientific notation with a mantissa and exponent. Either or both parts may be signed. Examples: `1.2E3', `1.2E-3', `-1.2E3', `-1.2E-3'. Two numbers that look similar may be treated differently. For example, `2.34' is an exact-value (fixed-point) number, whereas `2.34E0' is an approximate-value (floating-point) number. The *Note `DECIMAL': numeric-types. data type is a fixed-point type and calculations are exact. In MySQL, the *Note `DECIMAL': numeric-types. type has several synonyms: *Note `NUMERIC': numeric-types, *Note `DEC': numeric-types, *Note `FIXED': numeric-types. The integer types also are exact-value types. The *Note `FLOAT': numeric-types. and *Note `DOUBLE': numeric-types. data types are floating-point types and calculations are approximate. In MySQL, types that are synonymous with *Note `FLOAT': numeric-types. or *Note `DOUBLE': numeric-types. are *Note `DOUBLE PRECISION': numeric-types. and *Note `REAL': numeric-types.  File: manual.info, Node: precision-math-decimal-changes, Next: precision-math-expressions, Prev: precision-math-numbers, Up: precision-math 12.18.2 `DECIMAL' Data Type Changes ----------------------------------- This section discusses the characteristics of the *Note `DECIMAL': numeric-types. data type (and its synonyms) in MySQL 5.1, with particular regard to the following topics: * Maximum number of digits * Storage format * Storage requirements * The nonstandard MySQL extension to the upper range of *Note `DECIMAL': numeric-types. columns Possible incompatibilities with applications that are written for older versions of MySQL (prior to 5.0.3) are noted throughout this section. The declaration syntax for a *Note `DECIMAL': numeric-types. column is `DECIMAL(M,D)'. The ranges of values for the arguments in MySQL 5.1 are as follows: * M is the maximum number of digits (the precision). It has a range of 1 to 65. (Older versions of MySQL permitted a range of 1 to 254.) * D is the number of digits to the right of the decimal point (the scale). It has a range of 0 to 30 and must be no larger than M. The maximum value of 65 for M means that calculations on *Note `DECIMAL': numeric-types. values are accurate up to 65 digits. This limit of 65 digits of precision also applies to exact-value numeric literals, so the maximum range of such literals differs from before. (In older versions of MySQL, decimal values could have up to 254 digits. However, calculations were done using floating-point and thus were approximate, not exact.) Values for *Note `DECIMAL': numeric-types. columns in MySQL 5.1 are stored using a binary format that packs nine decimal digits into 4 bytes. The storage requirements for the integer and fractional parts of each value are determined separately. Each multiple of nine digits requires 4 bytes, and any remaining digits left over require some fraction of 4 bytes. The storage required for remaining digits is given by the following table. Leftover Digits Number of Bytes 0 0 1-2 1 3-4 2 5-6 3 7-9 4 For example, a `DECIMAL(18,9)' column has nine digits on either side of the decimal point, so the integer part and the fractional part each require 4 bytes. A `DECIMAL(20,6)' column has fourteen integer digits and six fractional digits. The integer digits require four bytes for nine of the digits and 3 bytes for the remaining five digits. The six fractional digits require 3 bytes. Unlike some older versions of MySQL, *Note `DECIMAL': numeric-types. columns in MySQL 5.1 do not store a leading `+' character or `-' character or leading `0' digits. If you insert `+0003.1' into a `DECIMAL(5,1)' column, it is stored as `3.1'. For negative numbers, a literal `-' character is not stored. Applications that rely on the older behavior must be modified to account for this change. *Note `DECIMAL': numeric-types. columns in MySQL 5.1 do not permit values larger than the range implied by the column definition. For example, a `DECIMAL(3,0)' column supports a range of `-999' to `999'. A `DECIMAL(M,D)' column permits at most M - D digits to the left of the decimal point. This is not compatible with applications relying on older versions of MySQL that permitted storing an extra digit in lieu of a `+' sign. The SQL standard requires that the precision of `NUMERIC(M,D)' be _exactly_ M digits. For `DECIMAL(M,D)', the standard requires a precision of at least M digits but permits more. In MySQL, `DECIMAL(M,D)' and `NUMERIC(M,D)' are the same, and both have a precision of exactly M digits. For more detailed information about porting applications that rely on the old treatment of the *Note `DECIMAL': numeric-types. data type, see the `MySQL 5.0 Reference Manual'.  File: manual.info, Node: precision-math-expressions, Next: precision-math-rounding, Prev: precision-math-decimal-changes, Up: precision-math 12.18.3 Expression Handling --------------------------- With precision math, exact-value numbers are used as given whenever possible. For example, numbers in comparisons are used exactly as given without a change in value. In strict SQL mode, for *Note `INSERT': insert. into a column with an exact data type (*Note `DECIMAL': numeric-types. or integer), a number is inserted with its exact value if it is within the column range. When retrieved, the value should be the same as what was inserted. (Without strict mode, truncation for *Note `INSERT': insert. is permissible.) Handling of a numeric expression depends on what kind of values the expression contains: * If any approximate values are present, the expression is approximate and is evaluated using floating-point arithmetic. * If no approximate values are present, the expression contains only exact values. If any exact value contains a fractional part (a value following the decimal point), the expression is evaluated using *Note `DECIMAL': numeric-types. exact arithmetic and has a precision of 65 digits. The term `exact' is subject to the limits of what can be represented in binary. For example, `1.0/3.0' can be approximated in decimal notation as `.333...', but not written as an exact number, so `(1.0/3.0)*3.0' does not evaluate to exactly `1.0'. * Otherwise, the expression contains only integer values. The expression is exact and is evaluated using integer arithmetic and has a precision the same as *Note `BIGINT': numeric-types. (64 bits). If a numeric expression contains any strings, they are converted to double-precision floating-point values and the expression is approximate. Inserts into numeric columns are affected by the SQL mode, which is controlled by the `sql_mode' system variable. (See *Note server-sql-mode::.) The following discussion mentions strict mode (selected by the `STRICT_ALL_TABLES' or `STRICT_TRANS_TABLES' mode values) and `ERROR_FOR_DIVISION_BY_ZERO'. To turn on all restrictions, you can simply use `TRADITIONAL' mode, which includes both strict mode values and `ERROR_FOR_DIVISION_BY_ZERO': mysql> SET sql_mode='TRADITIONAL'; If a number is inserted into an exact type column (*Note `DECIMAL': numeric-types. or integer), it is inserted with its exact value if it is within the column range. If the value has too many digits in the fractional part, rounding occurs and a warning is generated. Rounding is done as described in *Note precision-math-rounding::. If the value has too many digits in the integer part, it is too large and is handled as follows: * If strict mode is not enabled, the value is truncated to the nearest legal value and a warning is generated. * If strict mode is enabled, an overflow error occurs. Underflow is not detected, so underflow handing is undefined. By default, division by zero produces a result of `NULL' and no warning. With the `ERROR_FOR_DIVISION_BY_ZERO' SQL mode enabled, MySQL handles division by zero differently: * If strict mode is not enabled, a warning occurs. * If strict mode is enabled, inserts and updates involving division by zero are prohibited, and an error occurs. In other words, inserts and updates involving expressions that perform division by zero can be treated as errors, but this requires `ERROR_FOR_DIVISION_BY_ZERO' in addition to strict mode. Suppose that we have this statement: INSERT INTO t SET i = 1/0; This is what happens for combinations of strict and `ERROR_FOR_DIVISION_BY_ZERO' modes. `sql_mode' Value Result `''' (Default) No warning, no error; `i' is set to `NULL'. strict No warning, no error; `i' is set to `NULL'. `ERROR_FOR_DIVISION_BY_ZERO' Warning, no error; `i' is set to `NULL'. strict,`ERROR_FOR_DIVISION_BY_ZERO' Error condition; no row is inserted. For inserts of strings into numeric columns, conversion from string to number is handled as follows if the string has nonnumeric contents: * A string that does not begin with a number cannot be used as a number and produces an error in strict mode, or a warning otherwise. This includes the empty string. * A string that begins with a number can be converted, but the trailing nonnumeric portion is truncated. If the truncated portion contains anything other than spaces, this produces an error in strict mode, or a warning otherwise.  File: manual.info, Node: precision-math-rounding, Next: precision-math-examples, Prev: precision-math-expressions, Up: precision-math 12.18.4 Rounding Behavior ------------------------- This section discusses precision math rounding for the `ROUND()' function and for inserts into columns with exact-value types (*Note `DECIMAL': numeric-types. and integer). The `ROUND()' function rounds differently depending on whether its argument is exact or approximate: * For exact-value numbers, `ROUND()' uses the `round half up' rule: A value with a fractional part of .5 or greater is rounded up to the next integer if positive or down to the next integer if negative. (In other words, it is rounded away from zero.) A value with a fractional part less than .5 is rounded down to the next integer if positive or up to the next integer if negative. * For approximate-value numbers, the result depends on the C library. On many systems, this means that `ROUND()' uses the `round to nearest even' rule: A value with any fractional part is rounded to the nearest even integer. The following example shows how rounding differs for exact and approximate values: mysql> SELECT ROUND(2.5), ROUND(25E-1); +------------+--------------+ | ROUND(2.5) | ROUND(25E-1) | +------------+--------------+ | 3 | 2 | +------------+--------------+ For inserts into a *Note `DECIMAL': numeric-types. or integer column, the target is an exact data type, so rounding uses `round half up,' regardless of whether the value to be inserted is exact or approximate: mysql> CREATE TABLE t (d DECIMAL(10,0)); Query OK, 0 rows affected (0.00 sec) mysql> INSERT INTO t VALUES(2.5),(2.5E0); Query OK, 2 rows affected, 2 warnings (0.00 sec) Records: 2 Duplicates: 0 Warnings: 2 mysql> SELECT d FROM t; +------+ | d | +------+ | 3 | | 3 | +------+  File: manual.info, Node: precision-math-examples, Prev: precision-math-rounding, Up: precision-math 12.18.5 Precision Math Examples ------------------------------- This section provides some examples that show precision math query results in MySQL 5.1. These examples demonstrate the principles described in *Note precision-math-expressions::, and *Note precision-math-rounding::. *Example 1*. Numbers are used with their exact value as given when possible: mysql> SELECT (.1 + .2) = .3; +----------------+ | (.1 + .2) = .3 | +----------------+ | 1 | +----------------+ For floating-point values, results are inexact: mysql> SELECT (.1E0 + .2E0) = .3E0; +----------------------+ | (.1E0 + .2E0) = .3E0 | +----------------------+ | 0 | +----------------------+ Another way to see the difference in exact and approximate value handling is to add a small number to a sum many times. Consider the following stored procedure, which adds `.0001' to a variable 1,000 times. CREATE PROCEDURE p () BEGIN DECLARE i INT DEFAULT 0; DECLARE d DECIMAL(10,4) DEFAULT 0; DECLARE f FLOAT DEFAULT 0; WHILE i < 10000 DO SET d = d + .0001; SET f = f + .0001E0; SET i = i + 1; END WHILE; SELECT d, f; END; The sum for both `d' and `f' logically should be 1, but that is true only for the decimal calculation. The floating-point calculation introduces small errors: +--------+------------------+ | d | f | +--------+------------------+ | 1.0000 | 0.99999999999991 | +--------+------------------+ *Example 2*. Multiplication is performed with the scale required by standard SQL. That is, for two numbers X1 and X2 that have scale S1 and S2, the scale of the result is `S1 + S2': mysql> SELECT .01 * .01; +-----------+ | .01 * .01 | +-----------+ | 0.0001 | +-----------+ *Example 3*. Rounding behavior for exact-value numbers is well-defined: Rounding behavior (for example, with the `ROUND()' function) is independent of the implementation of the underlying C library, which means that results are consistent from platform to platform. * Rounding for exact-value columns (*Note `DECIMAL': numeric-types. and integer) and exact-valued numbers uses the `round half up' rule. Values with a fractional part of .5 or greater are rounded away from zero to the nearest integer, as shown here: mysql> SELECT ROUND(2.5), ROUND(-2.5); +------------+-------------+ | ROUND(2.5) | ROUND(-2.5) | +------------+-------------+ | 3 | -3 | +------------+-------------+ * Rounding for floating-point values uses the C library, which on many systems uses the `round to nearest even' rule. Values with any fractional part on such systems are rounded to the nearest even integer: mysql> SELECT ROUND(2.5E0), ROUND(-2.5E0); +--------------+---------------+ | ROUND(2.5E0) | ROUND(-2.5E0) | +--------------+---------------+ | 2 | -2 | +--------------+---------------+ *Example 4*. In strict mode, inserting a value that is out of range for a column causes an error, rather than truncation to a legal value. When MySQL is not running in strict mode, truncation to a legal value occurs: mysql> SET sql_mode=''; Query OK, 0 rows affected (0.00 sec) mysql> CREATE TABLE t (i TINYINT); Query OK, 0 rows affected (0.01 sec) mysql> INSERT INTO t SET i = 128; Query OK, 1 row affected, 1 warning (0.00 sec) mysql> SELECT i FROM t; +------+ | i | +------+ | 127 | +------+ 1 row in set (0.00 sec) However, an error occurs if strict mode is in effect: mysql> SET sql_mode='STRICT_ALL_TABLES'; Query OK, 0 rows affected (0.00 sec) mysql> CREATE TABLE t (i TINYINT); Query OK, 0 rows affected (0.00 sec) mysql> INSERT INTO t SET i = 128; ERROR 1264 (22003): Out of range value adjusted for column 'i' at row 1 mysql> SELECT i FROM t; Empty set (0.00 sec) *Example 5*: In strict mode and with `ERROR_FOR_DIVISION_BY_ZERO' set, division by zero causes an error, not a result of `NULL'. In nonstrict mode, division by zero has a result of `NULL': mysql> SET sql_mode=''; Query OK, 0 rows affected (0.01 sec) mysql> CREATE TABLE t (i TINYINT); Query OK, 0 rows affected (0.00 sec) mysql> INSERT INTO t SET i = 1 / 0; Query OK, 1 row affected (0.00 sec) mysql> SELECT i FROM t; +------+ | i | +------+ | NULL | +------+ 1 row in set (0.03 sec) However, division by zero is an error if the proper SQL modes are in effect: mysql> SET sql_mode='STRICT_ALL_TABLES,ERROR_FOR_DIVISION_BY_ZERO'; Query OK, 0 rows affected (0.00 sec) mysql> CREATE TABLE t (i TINYINT); Query OK, 0 rows affected (0.00 sec) mysql> INSERT INTO t SET i = 1 / 0; ERROR 1365 (22012): Division by 0 mysql> SELECT i FROM t; Empty set (0.01 sec) *Example 6*. Exact-value literals are evaluated as exact values. Prior to MySQL 5.0.3, exact-value and approximate-value literals both are evaluated as double-precision floating-point values: mysql> SELECT VERSION(); +------------+ | VERSION() | +------------+ | 4.1.18-log | +------------+ 1 row in set (0.01 sec) mysql> CREATE TABLE t SELECT 2.5 AS a, 25E-1 AS b; Query OK, 1 row affected (0.07 sec) Records: 1 Duplicates: 0 Warnings: 0 mysql> DESCRIBE t; +-------+-------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +-------+-------------+------+-----+---------+-------+ | a | double(3,1) | | | 0.0 | | | b | double | | | 0 | | +-------+-------------+------+-----+---------+-------+ 2 rows in set (0.04 sec) As of MySQL 5.0.3, the approximate-value literal is evaluated using floating point, but the exact-value literal is handled as *Note `DECIMAL': numeric-types.: mysql> SELECT VERSION(); +-----------------+ | VERSION() | +-----------------+ | 5.1.6-alpha-log | +-----------------+ 1 row in set (0.11 sec) mysql> CREATE TABLE t SELECT 2.5 AS a, 25E-1 AS b; Query OK, 1 row affected (0.01 sec) Records: 1 Duplicates: 0 Warnings: 0 mysql> DESCRIBE t; +-------+-----------------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +-------+-----------------------+------+-----+---------+-------+ | a | decimal(2,1) unsigned | NO | | 0.0 | | | b | double | NO | | 0 | | +-------+-----------------------+------+-----+---------+-------+ 2 rows in set (0.01 sec) *Example 7*. If the argument to an aggregate function is an exact numeric type, the result is also an exact numeric type, with a scale at least that of the argument. Consider these statements: mysql> CREATE TABLE t (i INT, d DECIMAL, f FLOAT); mysql> INSERT INTO t VALUES(1,1,1); mysql> CREATE TABLE y SELECT AVG(i), AVG(d), AVG(f) FROM t; Before MySQL 5.0.3, the result is a double no matter the argument type: mysql> DESCRIBE y; +--------+--------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +--------+--------------+------+-----+---------+-------+ | AVG(i) | double(17,4) | YES | | NULL | | | AVG(d) | double(17,4) | YES | | NULL | | | AVG(f) | double | YES | | NULL | | +--------+--------------+------+-----+---------+-------+ As of MySQL 5.0.3, the result is a double only for the floating-point argument. For exact type arguments, the result is also an exact type: mysql> DESCRIBE y; +--------+---------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +--------+---------------+------+-----+---------+-------+ | AVG(i) | decimal(14,4) | YES | | NULL | | | AVG(d) | decimal(14,4) | YES | | NULL | | | AVG(f) | double | YES | | NULL | | +--------+---------------+------+-----+---------+-------+ The result is a double only for the floating-point argument. For exact type arguments, the result is also an exact type.  File: manual.info, Node: sql-syntax, Next: storage-engines, Prev: functions, Up: Top 13 SQL Statement Syntax *********************** * Menu: * sql-syntax-data-definition:: Data Definition Statements * sql-syntax-data-manipulation:: Data Manipulation Statements * sql-syntax-transactions:: MySQL Transactional and Locking Statements * sql-syntax-server-administration:: Database Administration Statements * sql-syntax-replication:: Replication Statements * sql-syntax-prepared-statements:: SQL Syntax for Prepared Statements * sql-syntax-compound-statements:: MySQL Compound-Statement Syntax * sql-syntax-utility:: MySQL Utility Statements This chapter describes the syntax for the SQL statements supported by MySQL.  File: manual.info, Node: sql-syntax-data-definition, Next: sql-syntax-data-manipulation, Prev: sql-syntax, Up: sql-syntax 13.1 Data Definition Statements =============================== * Menu: * alter-database:: `ALTER DATABASE' Syntax * alter-event:: `ALTER EVENT' Syntax * alter-logfile-group:: `ALTER LOGFILE GROUP' Syntax * alter-function:: `ALTER FUNCTION' Syntax * alter-procedure:: `ALTER PROCEDURE' Syntax * alter-server:: `ALTER SERVER' Syntax * alter-table:: `ALTER TABLE' Syntax * alter-tablespace:: `ALTER TABLESPACE' Syntax * alter-view:: `ALTER VIEW' Syntax * create-database:: `CREATE DATABASE' Syntax * create-event:: `CREATE EVENT' Syntax * create-function:: The `CREATE FUNCTION' Statement * create-index:: `CREATE INDEX' Syntax * create-logfile-group:: `CREATE LOGFILE GROUP' Syntax * create-procedure:: `CREATE PROCEDURE' and `CREATE FUNCTION' Syntax * create-server:: `CREATE SERVER' Syntax * create-table:: `CREATE TABLE' Syntax * create-tablespace:: `CREATE TABLESPACE' Syntax * create-trigger:: `CREATE TRIGGER' Syntax * create-view:: `CREATE VIEW' Syntax * drop-database:: `DROP DATABASE' Syntax * drop-event:: `DROP EVENT' Syntax * drop-function:: `DROP FUNCTION' Syntax * drop-index:: `DROP INDEX' Syntax * drop-logfile-group:: `DROP LOGFILE GROUP' Syntax * drop-procedure:: `DROP PROCEDURE' and `DROP FUNCTION' Syntax * drop-server:: `DROP SERVER' Syntax * drop-table:: `DROP TABLE' Syntax * drop-tablespace:: `DROP TABLESPACE' Syntax * drop-trigger:: `DROP TRIGGER' Syntax * drop-view:: `DROP VIEW' Syntax * rename-database:: `RENAME DATABASE' Syntax * rename-table:: `RENAME TABLE' Syntax * truncate-table:: `TRUNCATE TABLE' Syntax  File: manual.info, Node: alter-database, Next: alter-event, Prev: sql-syntax-data-definition, Up: sql-syntax-data-definition 13.1.1 `ALTER DATABASE' Syntax ------------------------------ ALTER {DATABASE | SCHEMA} [DB_NAME] ALTER_SPECIFICATION ... ALTER {DATABASE | SCHEMA} DB_NAME UPGRADE DATA DIRECTORY NAME ALTER_SPECIFICATION: [DEFAULT] CHARACTER SET [=] CHARSET_NAME | [DEFAULT] COLLATE [=] COLLATION_NAME *Note `ALTER DATABASE': alter-database. enables you to change the overall characteristics of a database. These characteristics are stored in the `db.opt' file in the database directory. To use *Note `ALTER DATABASE': alter-database, you need the `ALTER' privilege on the database. *Note `ALTER SCHEMA': alter-database. is a synonym for *Note `ALTER DATABASE': alter-database. The `CHARACTER SET' clause changes the default database character set. The `COLLATE' clause changes the default database collation. *Note charset::, discusses character set and collation names. You can see what character sets and collations are available using, respectively, the *Note `SHOW CHARACTER SET': show-character-set. and *Note `SHOW COLLATION': show-collation. statements. See *Note show-character-set::, and *Note show-collation::, for more information. The database name can be omitted from the first syntax, in which case the statement applies to the default database. The syntax that includes the `UPGRADE DATA DIRECTORY NAME' clause was added in MySQL 5.1.23. It updates the name of the directory associated with the database to use the encoding implemented in MySQL 5.1 for mapping database names to database directory names (see *Note identifier-mapping::). This clause is for use under these conditions: * It is intended when upgrading MySQL to 5.1 or later from older versions. * It is intended to update a database directory name to the current encoding format if the name contains special characters that need encoding. * The statement is used by *Note `mysqlcheck': mysqlcheck. (as invoked by *Note `mysql_upgrade': mysql-upgrade.). For example, if a database in MySQL 5.0 has the name `a-b-c', the name contains instances of the `-' (dash) character. In MySQL 5.0, the database directory is also named `a-b-c', which is not necessarily safe for all file systems. In MySQL 5.1 and later, the same database name is encoded as `a@002db@002dc' to produce a file system-neutral directory name. When a MySQL installation is upgraded to MySQL 5.1 or later from an older version,the server displays a name such as `a-b-c' (which is in the old format) as `#mysql50#a-b-c', and you must refer to the name using the `#mysql50#' prefix. Use `UPGRADE DATA DIRECTORY NAME' in this case to explicitly tell the server to re-encode the database directory name to the current encoding format: ALTER DATABASE `#mysql50#a-b-c` UPGRADE DATA DIRECTORY NAME; After executing this statement, you can refer to the database as `a-b-c' without the special `#mysql50#' prefix.  File: manual.info, Node: alter-event, Next: alter-logfile-group, Prev: alter-database, Up: sql-syntax-data-definition 13.1.2 `ALTER EVENT' Syntax --------------------------- ALTER [DEFINER = { USER | CURRENT_USER }] EVENT EVENT_NAME [ON SCHEDULE SCHEDULE] [ON COMPLETION [NOT] PRESERVE] [RENAME TO NEW_EVENT_NAME] [ENABLE | DISABLE | DISABLE ON SLAVE] [COMMENT 'COMMENT'] [DO EVENT_BODY] The *Note `ALTER EVENT': alter-event. statement is used to change one or more of the characteristics of an existing event without the need to drop and recreate it. The syntax for each of the `DEFINER', `ON SCHEDULE', `ON COMPLETION', `COMMENT', `ENABLE' / `DISABLE', and *Note `DO': do. clauses is exactly the same as when used with *Note `CREATE EVENT': create-event. (See *Note create-event::.) Support for the `DEFINER' clause was added in MySQL 5.1.17. Beginning with MySQL 5.1.12, this statement requires the `EVENT' privilege. When a user executes a successful *Note `ALTER EVENT': alter-event. statement, that user becomes the definer for the affected event. (In MySQL 5.1.11 and earlier, an event could be altered only by its definer, or by a user having the `SUPER' privilege.) *Note `ALTER EVENT': alter-event. works only with an existing event: mysql> ALTER EVENT no_such_event > ON SCHEDULE > EVERY '2:3' DAY_HOUR; `ERROR 1517 (HY000): Unknown event 'no_such_event'' In each of the following examples, assume that the event named `myevent' is defined as shown here: CREATE EVENT myevent ON SCHEDULE EVERY 6 HOUR COMMENT 'A sample comment.' DO UPDATE myschema.mytable SET mycol = mycol + 1; The following statement changes the schedule for `myevent' from once every six hours starting immediately to once every twelve hours, starting four hours from the time the statement is run: ALTER EVENT myevent ON SCHEDULE EVERY 12 HOUR STARTS CURRENT_TIMESTAMP + INTERVAL 4 HOUR; It is possible to change multiple characteristics of an event in a single statement. This example changes the SQL statement executed by `myevent' to one that deletes all records from `mytable'; it also changes the schedule for the event such that it executes once, one day after this *Note `ALTER EVENT': alter-event. statement is run. ALTER TABLE myevent ON SCHEDULE AT CURRENT_TIMESTAMP + INTERVAL 1 DAY DO TRUNCATE TABLE myschema.mytable; It is necessary to include only those options in an *Note `ALTER EVENT': alter-event. statement which correspond to characteristics that you actually wish to change; options which are omitted retain their existing values. This includes any default values for *Note `CREATE EVENT': create-event. such as `ENABLE'. To disable `myevent', use this *Note `ALTER EVENT': alter-event. statement: ALTER EVENT myevent DISABLE; The `ON SCHEDULE' clause may use expressions involving built-in MySQL functions and user variables to obtain any of the TIMESTAMP or INTERVAL values which it contains. You may not use stored routines or user-defined functions in such expressions, nor may you use any table references; however, you may use `SELECT FROM DUAL'. This is true for both *Note `ALTER EVENT': alter-event. and *Note `CREATE EVENT': create-event. statements. Beginning with MySQL 5.1.13, references to stored routines, user-defined functions, and tables in such cases are specifically not permitted, and fail with an error (see Bug#22830). An *Note `ALTER EVENT': alter-event. statement that contains another *Note `ALTER EVENT': alter-event. statement in its *Note `DO': do. clause appears to succeed; however, when the server attempts to execute the resulting scheduled event, the execution fails with an error. To rename an event, use the *Note `ALTER EVENT': alter-event. statement's `RENAME TO' clause. This statement renames the event `myevent' to `yourevent': ALTER EVENT myevent RENAME TO yourevent; You can also move an event to a different database using `ALTER EVENT ... RENAME TO ...' and `DB_NAME.EVENT_NAME' notation, as shown here: ALTER EVENT olddb.myevent RENAME TO newdb.myevent; To execute the previous statement, the user executing it must have the `EVENT' privilege on both the `olddb' and `newdb' databases. *Note*: There is no `RENAME EVENT' statement. Beginning with MySQL 5.1.18, a third value may also appear in place of `ENABLED' or `DISABLED'; `DISABLE ON SLAVE' is used on a replication slave to indicate an event which was created on the master and replicated to the slave, but which is not executed on the slave. Normally, `DISABLE ON SLAVE' is set automatically as required; however, there are some circumstances under which you may want or need to change it manually. See *Note replication-features-invoked::, for more information.  File: manual.info, Node: alter-logfile-group, Next: alter-function, Prev: alter-event, Up: sql-syntax-data-definition 13.1.3 `ALTER LOGFILE GROUP' Syntax ----------------------------------- ALTER LOGFILE GROUP LOGFILE_GROUP ADD UNDOFILE 'FILE_NAME' [INITIAL_SIZE [=] SIZE] [WAIT] ENGINE [=] ENGINE_NAME This statement adds an `UNDO' file named 'FILE_NAME' to an existing log file group LOGFILE_GROUP. An *Note `ALTER LOGFILE GROUP': alter-logfile-group. statement has one and only one `ADD UNDOFILE' clause. No `DROP UNDOFILE' clause is currently supported. *Note*: All MySQL Cluster Disk Data objects share the same namespace. This means that _each Disk Data object_ must be uniquely named (and not merely each Disk Data object of a given type). For example, you cannot have a tablespace and an undo log file with the same name, or an undo log file and a data file with the same name. Prior to MySQL Cluster NDB 6.2.17, 6.3.23, and 6.4.3, path and file names for undo log files could not be longer than 128 characters. (Bug#31769) The optional `INITIAL_SIZE' parameter sets the `UNDO' file's initial size in bytes; if not specified, the initial size default to `128M' (128 megabytes). You may optionally follow SIZE with a one-letter abbreviation for an order of magnitude, similar to those used in `my.cnf'. Generally, this is one of the letters `M' (for megabytes) or `G' (for gigabytes). On 32-bit systems, the maximum supported value for `INITIAL_SIZE' is `4G'. (Bug#29186) Beginning with MySQL Cluster NDB 6.2.18, 6.3.24, and 7.0.4, the minimum permitted value for `INITIAL_SIZE' is `1M'. (Bug#29574) *Note*: `WAIT' is parsed but otherwise ignored. This keyword has no effect in MySQL 5.1, MySQL Cluster NDB 6.x, or MySQL Cluster NDB 7.x, and is intended for future expansion. The `ENGINE' parameter (required) determines the storage engine which is used by this log file group, with ENGINE_NAME being the name of the storage engine. In MySQL 5.1, MySQL Cluster NDB 6.x, and MySQL Cluster NDB 7.x, the only accepted values for ENGINE_NAME are `*Note `NDBCLUSTER': mysql-cluster.' and `*Note `NDB': mysql-cluster.'. The two values are equivalent. Here is an example, which assumes that the log file group `lg_3' has already been created using *Note `CREATE LOGFILE GROUP': create-logfile-group. (see *Note create-logfile-group::): ALTER LOGFILE GROUP lg_3 ADD UNDOFILE 'undo_10.dat' INITIAL_SIZE=32M ENGINE=NDBCLUSTER; When *Note `ALTER LOGFILE GROUP': alter-logfile-group. is used with `ENGINE = NDBCLUSTER' (alternatively, `ENGINE = NDB'), an `UNDO' log file is created on each MySQL Cluster data node. You can verify that the `UNDO' files were created and obtain information about them by querying the *Note `INFORMATION_SCHEMA.FILES': files-table. table. For example: mysql> SELECT FILE_NAME, LOGFILE_GROUP_NUMBER, EXTRA -> FROM INFORMATION_SCHEMA.FILES -> WHERE LOGFILE_GROUP_NAME = 'lg_3'; +-------------+----------------------+----------------+ | FILE_NAME | LOGFILE_GROUP_NUMBER | EXTRA | +-------------+----------------------+----------------+ | newdata.dat | 0 | CLUSTER_NODE=3 | | newdata.dat | 0 | CLUSTER_NODE=4 | | undo_10.dat | 11 | CLUSTER_NODE=3 | | undo_10.dat | 11 | CLUSTER_NODE=4 | +-------------+----------------------+----------------+ 4 rows in set (0.01 sec) (See *Note files-table::.) Memory used for `UNDO_BUFFER_SIZE' comes from the global pool whose size is determined by the value of the `SharedGlobalMemory' data node configuration parameter. This includes any default value implied for this option by the setting of the `InitialLogFileGroup' data node configuration parameter. *Note `ALTER LOGFILE GROUP': alter-logfile-group. was added in MySQL 5.1.6. It is useful only with Disk Data storage for MySQL Cluster. For more information, see *Note mysql-cluster-disk-data::.  File: manual.info, Node: alter-function, Next: alter-procedure, Prev: alter-logfile-group, Up: sql-syntax-data-definition 13.1.4 `ALTER FUNCTION' Syntax ------------------------------ ALTER FUNCTION FUNC_NAME [CHARACTERISTIC ...] CHARACTERISTIC: { CONTAINS SQL | NO SQL | READS SQL DATA | MODIFIES SQL DATA } | SQL SECURITY { DEFINER | INVOKER } | COMMENT 'STRING' This statement can be used to change the characteristics of a stored function. More than one change may be specified in an *Note `ALTER FUNCTION': alter-function. statement. However, you cannot change the parameters or body of a stored function using this statement; to make such changes, you must drop and re-create the function using *Note `DROP FUNCTION': drop-function. and *Note `CREATE FUNCTION': create-function. You must have the `ALTER ROUTINE' privilege for the function. (That privilege is granted automatically to the function creator.) If binary logging is enabled, the *Note `ALTER FUNCTION': alter-function. statement might also require the `SUPER' privilege, as described in *Note stored-programs-logging::.  File: manual.info, Node: alter-procedure, Next: alter-server, Prev: alter-function, Up: sql-syntax-data-definition 13.1.5 `ALTER PROCEDURE' Syntax ------------------------------- ALTER PROCEDURE PROC_NAME [CHARACTERISTIC ...] CHARACTERISTIC: COMMENT 'STRING' | { CONTAINS SQL | NO SQL | READS SQL DATA | MODIFIES SQL DATA } | SQL SECURITY { DEFINER | INVOKER } This statement can be used to change the characteristics of a stored procedure. More than one change may be specified in an *Note `ALTER PROCEDURE': alter-procedure. statement. However, you cannot change the parameters or body of a stored procedure using this statement; to make such changes, you must drop and re-create the procedure using *Note `DROP PROCEDURE': drop-procedure. and *Note `CREATE PROCEDURE': create-procedure. You must have the `ALTER ROUTINE' privilege for the procedure. By default, that privilege is granted automatically to the procedure creator. This behavior can be changed by disabling the `automatic_sp_privileges' system variable. See *Note stored-routines-privileges::.  File: manual.info, Node: alter-server, Next: alter-table, Prev: alter-procedure, Up: sql-syntax-data-definition 13.1.6 `ALTER SERVER' Syntax ---------------------------- ALTER SERVER SERVER_NAME OPTIONS (OPTION [, OPTION] ...) Alters the server information for `SERVER_NAME', adjusting the specified options as per the *Note `CREATE SERVER': create-server. statement. See *Note create-server::. The corresponding fields in the `mysql.servers' table are updated accordingly. This statement requires the `SUPER' privilege. For example, to update the `USER' option: ALTER SERVER s OPTIONS (USER 'sally'); *Note `ALTER SERVER': alter-server. does not cause an automatic commit. *Note `ALTER SERVER': alter-server. was added in MySQL 5.1.15.  File: manual.info, Node: alter-table, Next: alter-tablespace, Prev: alter-server, Up: sql-syntax-data-definition 13.1.7 `ALTER TABLE' Syntax --------------------------- * Menu: * alter-table-partition-operations:: `ALTER TABLE' Partition Operations * alter-table-online-operations:: `ALTER TABLE' Online Operations * alter-table-examples:: `ALTER TABLE' Examples ALTER [ONLINE | OFFLINE] [IGNORE] TABLE TBL_NAME ALTER_SPECIFICATION [, ALTER_SPECIFICATION] ... [PARTITION_OPTIONS] ALTER [ONLINE | OFFLINE] [IGNORE] TABLE TBL_NAME PARTITION_OPTIONS ALTER_SPECIFICATION: TABLE_OPTIONS | ADD [COLUMN] COL_NAME COLUMN_DEFINITION [FIRST | AFTER COL_NAME ] | ADD [COLUMN] (COL_NAME COLUMN_DEFINITION,...) | ADD {INDEX|KEY} [INDEX_NAME] [INDEX_TYPE] (INDEX_COL_NAME,...) [INDEX_OPTION] ... | ADD [CONSTRAINT [SYMBOL]] PRIMARY KEY [INDEX_TYPE] (INDEX_COL_NAME,...) [INDEX_OPTION] ... | ADD [CONSTRAINT [SYMBOL]] UNIQUE [INDEX|KEY] [INDEX_NAME] [INDEX_TYPE] (INDEX_COL_NAME,...) [INDEX_OPTION] ... | ADD FULLTEXT [INDEX|KEY] [INDEX_NAME] (INDEX_COL_NAME,...) [INDEX_OPTION] ... | ADD SPATIAL [INDEX|KEY] [INDEX_NAME] (INDEX_COL_NAME,...) [INDEX_OPTION] ... | ADD [CONSTRAINT [SYMBOL]] FOREIGN KEY [INDEX_NAME] (INDEX_COL_NAME,...) REFERENCE_DEFINITION | ALTER [COLUMN] COL_NAME {SET DEFAULT LITERAL | DROP DEFAULT} | CHANGE [COLUMN] OLD_COL_NAME NEW_COL_NAME COLUMN_DEFINITION [FIRST|AFTER COL_NAME] | MODIFY [COLUMN] COL_NAME COLUMN_DEFINITION [FIRST | AFTER COL_NAME] | DROP [COLUMN] COL_NAME | DROP PRIMARY KEY | DROP {INDEX|KEY} INDEX_NAME | DROP FOREIGN KEY FK_SYMBOL | DISABLE KEYS | ENABLE KEYS | RENAME [TO] NEW_TBL_NAME | ORDER BY COL_NAME [, COL_NAME] ... | CONVERT TO CHARACTER SET CHARSET_NAME [COLLATE COLLATION_NAME] | [DEFAULT] CHARACTER SET [=] CHARSET_NAME [COLLATE [=] COLLATION_NAME] | DISCARD TABLESPACE | IMPORT TABLESPACE | ADD PARTITION (PARTITION_DEFINITION) | DROP PARTITION PARTITION_NAMES | COALESCE PARTITION NUMBER | REORGANIZE PARTITION [PARTITION_NAMES INTO (PARTITION_DEFINITIONS)] | ANALYZE PARTITION {PARTITION_NAMES | ALL } | CHECK PARTITION {PARTITION_NAMES | ALL } | OPTIMIZE PARTITION {PARTITION_NAMES | ALL } | REBUILD PARTITION {PARTITION_NAMES | ALL } | REPAIR PARTITION {PARTITION_NAMES | ALL } | PARTITION BY PARTITIONING_EXPRESSION | REMOVE PARTITIONING INDEX_COL_NAME: COL_NAME [(LENGTH)] [ASC | DESC] INDEX_TYPE: USING {BTREE | HASH} INDEX_OPTION: KEY_BLOCK_SIZE [=] VALUE | INDEX_TYPE | WITH PARSER PARSER_NAME TABLE_OPTIONS: TABLE_OPTION [[,] TABLE_OPTION] ... (see *Note `CREATE TABLE': create-table. options) PARTITION_OPTIONS: (see *Note `CREATE TABLE': create-table. options) *Note `ALTER TABLE': alter-table. enables you to change the structure of a table. For example, you can add or delete columns, create or destroy indexes, change the type of existing columns, or rename columns or the table itself. You can also change the comment for the table and type of the table. A number of partitioning-related extensions to *Note `ALTER TABLE': alter-table. were added in MySQL 5.1.5. These can be used with partitioned tables for repartitioning, for adding, dropping, merging, and splitting partitions, and for performing partitioning maintenance. For more information, see *Note alter-table-partition-operations::. The syntax for many of the permissible alterations is similar to clauses of the *Note `CREATE TABLE': create-table. statement. See *Note create-table::, for more information. Some operations may result in warnings if attempted on a table for which the storage engine does not support the operation. These warnings can be displayed with *Note `SHOW WARNINGS': show-warnings. See *Note show-warnings::. For information on troubleshooting *Note `ALTER TABLE': alter-table, see *Note alter-table-problems::. In most cases, *Note `ALTER TABLE': alter-table. makes a temporary copy of the original table. MySQL waits for other operations that are modifying the table, then proceeds. It incorporates the alteration into the copy, deletes the original table, and renames the new one. While *Note `ALTER TABLE': alter-table. is executing, the original table is readable by other sessions. Updates and writes to the table that begin after the *Note `ALTER TABLE': alter-table. operation begins are stalled until the new table is ready, then are automatically redirected to the new table without any failed updates. The temporary table is created in the database directory of the new table. This can differ from the database directory of the original table for *Note `ALTER TABLE': alter-table. operations that rename the table to a different database. For `MyISAM' tables, you can speed up index re-creation (the slowest part of the alteration process) by setting the `myisam_sort_buffer_size' system variable to a high value. For some operations, an in-place *Note `ALTER TABLE': alter-table. is possible that does not require a temporary table: * For `ALTER TABLE TBL_NAME RENAME TO NEW_TBL_NAME' without any other options, MySQL simply renames any files that correspond to the table TBL_NAME without making a copy. (You can also use the *Note `RENAME TABLE': rename-table. statement to rename tables. See *Note rename-table::.) Any privileges granted specifically for the renamed table are not migrated to the new name. They must be changed manually. * Alterations that modify only table metadata and not table data can be made immediately by altering the table's `.frm' file and not touching table contents. The following changes are fast alterations that can be made this way: * Renaming a column, except for the *Note `InnoDB': innodb-storage-engine. storage engine. * Changing the default value of a column (except for *Note `NDB': mysql-cluster. tables; see Limitations of *Note `NDBCLUSTER': mysql-cluster. online operations). * Changing the definition of an *Note `ENUM': enum. or *Note `SET': set. column by adding new enumeration or set members to the _end_ of the list of valid member values, as long as the storage side of the data type does not change. For example, adding a member to a *Note `SET': set. column that has 8 members changes the required storage per value from 1 byte to 2 bytes; this will require a table copy. Adding members in the middle of the list causes renumbering of existing members, which requires a table copy. * `ALTER TABLE ... ADD PARTITION' creates no temporary table except except when used with *Note `NDB': mysql-cluster. tables. `ADD' or `DROP' operations for `RANGE' or `LIST' partitions are immediate operations or nearly so. `ADD' or `COALESCE' operations for `HASH' or `KEY' partitions copy data between changed partitions; unless `LINEAR HASH' or `LINEAR KEY' was used, this is much the same as creating a new table (although the operation is done partition by partition). `REORGANIZE' operations copy only changed partitions and do not touch unchanged ones. * Renaming an index, except for *Note `InnoDB': innodb-storage-engine. * Adding or dropping an index, for *Note `InnoDB': innodb-storage-engine. (if `InnoDB Plugin' is used) and *Note `NDB': mysql-cluster. You can force an `ALTER TABLE' operation that would otherwise not require a table copy to use the temporary table method (as supported in MySQL 5.0) by setting the `old_alter_table' system variable to `ON'. Operations that add and drop indexes on variable-width columns of *Note `NDBCLUSTER': mysql-cluster. tables occur online, without any table copying and without blocking concurrent DML actions for most of their duration. For more information, see *Note alter-table-online-operations::. * To use *Note `ALTER TABLE': alter-table, you need `ALTER', `CREATE', and `INSERT' privileges for the table. Renaming a table requires `ALTER' and `DROP' on the old table, `ALTER', `CREATE', and `INSERT' on the new table. * `IGNORE' is a MySQL extension to standard SQL. It controls how *Note `ALTER TABLE': alter-table. works if there are duplicates on unique keys in the new table or if warnings occur when strict mode is enabled. If `IGNORE' is not specified, the copy is aborted and rolled back if duplicate-key errors occur. If `IGNORE' is specified, only the first row is used of rows with duplicates on a unique key. The other conflicting rows are deleted. Incorrect values are truncated to the closest matching acceptable value. * TABLE_OPTION signifies a table option of the kind that can be used in the *Note `CREATE TABLE': create-table. statement, such as `ENGINE', `AUTO_INCREMENT', or `AVG_ROW_LENGTH'. (*Note create-table::, lists all table options.) However, *Note `ALTER TABLE': alter-table. ignores the `DATA DIRECTORY' and `INDEX DIRECTORY' table options. For example, to convert a table to be an `InnoDB' table, use this statement: ALTER TABLE t1 ENGINE = InnoDB; The outcome of attempting to change a table's storage engine is affected by whether the desired storage engine is available and the setting of the `NO_ENGINE_SUBSTITUTION' SQL mode, as described in *Note server-sql-mode::. As of MySQL 5.1.11, to prevent inadvertent loss of data, *Note `ALTER TABLE': alter-table. cannot be used to change the storage engine of a table to `MERGE' or `BLACKHOLE'. To change the value of the `AUTO_INCREMENT' counter to be used for new rows, do this: ALTER TABLE t2 AUTO_INCREMENT = VALUE; You cannot reset the counter to a value less than or equal to any that have already been used. For `MyISAM', if the value is less than or equal to the maximum value currently in the `AUTO_INCREMENT' column, the value is reset to the current maximum plus one. For `InnoDB', _if the value is less than the current maximum value in the column, no error occurs and the current sequence value is not changed._ * You can issue multiple `ADD', `ALTER', `DROP', and `CHANGE' clauses in a single *Note `ALTER TABLE': alter-table. statement, separated by commas. This is a MySQL extension to standard SQL, which permits only one of each clause per *Note `ALTER TABLE': alter-table. statement. For example, to drop multiple columns in a single statement, do this: ALTER TABLE t2 DROP COLUMN c, DROP COLUMN d; * `CHANGE COL_NAME', `DROP COL_NAME', and `DROP INDEX' are MySQL extensions to standard SQL. * `MODIFY' is an Oracle extension to *Note `ALTER TABLE': alter-table. * The word `COLUMN' is optional and can be omitted. * COLUMN_DEFINITION clauses use the same syntax for `ADD' and `CHANGE' as for *Note `CREATE TABLE': create-table. See *Note create-table::. * You can rename a column using a `CHANGE OLD_COL_NAME NEW_COL_NAME COLUMN_DEFINITION' clause. To do so, specify the old and new column names and the definition that the column currently has. For example, to rename an *Note `INTEGER': numeric-types. column from `a' to `b', you can do this: ALTER TABLE t1 CHANGE a b INTEGER; If you want to change a column's type but not the name, `CHANGE' syntax still requires an old and new column name, even if they are the same. For example: ALTER TABLE t1 CHANGE b b BIGINT NOT NULL; You can also use `MODIFY' to change a column's type without renaming it: ALTER TABLE t1 MODIFY b BIGINT NOT NULL; When you use `CHANGE' or `MODIFY', COLUMN_DEFINITION must include the data type and all attributes that should apply to the new column, other than index attributes such as `PRIMARY KEY' or `UNIQUE'. Attributes present in the original definition but not specified for the new definition are not carried forward. Suppose that a column `col1' is defined as `INT UNSIGNED DEFAULT 1 COMMENT 'my column'' and you modify the column as follows: ALTER TABLE t1 MODIFY col1 BIGINT; The resulting column will be defined as `BIGINT', but will not include the attributes `UNSIGNED DEFAULT 1 COMMENT 'my column''. To retain them, the statement should be: ALTER TABLE t1 MODIFY col1 BIGINT UNSIGNED DEFAULT 1 COMMENT 'my column'; * When you change a data type using `CHANGE' or `MODIFY', MySQL tries to convert existing column values to the new type as well as possible. *Warning*: This conversion may result in alteration of data. For example, if you shorten a string column, values may be truncated. To prevent the operation from succeeding if conversions to the new data type would result in loss of data, enable strict SQL mode before using *Note `ALTER TABLE': alter-table. (see *Note server-sql-mode::). * To add a column at a specific position within a table row, use `FIRST' or `AFTER COL_NAME'. The default is to add the column last. You can also use `FIRST' and `AFTER' in `CHANGE' or `MODIFY' operations to reorder columns within a table. * `ALTER ... SET DEFAULT' or `ALTER ... DROP DEFAULT' specify a new default value for a column or remove the old default value, respectively. If the old default is removed and the column can be `NULL', the new default is `NULL'. If the column cannot be `NULL', MySQL assigns a default value as described in *Note data-type-defaults::. * *Note `DROP INDEX': drop-index. removes an index. This is a MySQL extension to standard SQL. See *Note drop-index::. If you are unsure of the index name, use `SHOW INDEX FROM TBL_NAME'. * If columns are dropped from a table, the columns are also removed from any index of which they are a part. If all columns that make up an index are dropped, the index is dropped as well. If you use `CHANGE' or `MODIFY' to shorten a column for which an index exists on the column, and the resulting column length is less than the index length, MySQL shortens the index automatically. * If a table contains only one column, the column cannot be dropped. If what you intend is to remove the table, use *Note `DROP TABLE': drop-table. instead. * `DROP PRIMARY KEY' drops the primary key. If there is no primary key, an error occurs. If you add a `UNIQUE INDEX' or `PRIMARY KEY' to a table, it is stored before any nonunique index so that MySQL can detect duplicate keys as early as possible. * Some storage engines permit you to specify an index type when creating an index. The syntax for the INDEX_TYPE specifier is `USING TYPE_NAME'. For details about `USING', see *Note create-index::. Before MySQL 5.1.10, `USING' can be given only before the index column list. As of 5.1.10, the preferred position is after the column list. Support for use of the option before the column list will be removed in a future MySQL release. INDEX_OPTION values specify additional options for an index. `USING' is one such option. For details about permissible INDEX_OPTION values, see *Note create-index::. * After an *Note `ALTER TABLE': alter-table. statement, it may be necessary to run *Note `ANALYZE TABLE': analyze-table. to update index cardinality information. See *Note show-index::. * `ORDER BY' enables you to create the new table with the rows in a specific order. Note that the table does not remain in this order after inserts and deletes. This option is useful primarily when you know that you are mostly to query the rows in a certain order most of the time. By using this option after major changes to the table, you might be able to get higher performance. In some cases, it might make sorting easier for MySQL if the table is in order by the column that you want to order it by later. `ORDER BY' syntax permits one or more column names to be specified for sorting, each of which optionally can be followed by `ASC' or `DESC' to indicate ascending or descending sort order, respectively. The default is ascending order. Only column names are permitted as sort criteria; arbitrary expressions are not permitted. `ORDER BY' does not make sense for `InnoDB' tables that contain a user-defined clustered index (`PRIMARY KEY' or `NOT NULL UNIQUE' index). `InnoDB' always orders table rows according to such an index if one is present. *Note*: When used on a partitioned table, `ALTER TABLE ... ORDER BY' orders rows within each partition only. * If you use *Note `ALTER TABLE': alter-table. on a `MyISAM' table, all nonunique indexes are created in a separate batch (as for *Note `REPAIR TABLE': repair-table.). This should make *Note `ALTER TABLE': alter-table. much faster when you have many indexes. This feature can be activated explicitly for a `MyISAM' table. `ALTER TABLE ... DISABLE KEYS' tells MySQL to stop updating nonunique indexes. `ALTER TABLE ... ENABLE KEYS' then should be used to re-create missing indexes. MySQL does this with a special algorithm that is much faster than inserting keys one by one, so disabling keys before performing bulk insert operations should give a considerable speedup. Using `ALTER TABLE ... DISABLE KEYS' requires the `INDEX' privilege in addition to the privileges mentioned earlier. While the nonunique indexes are disabled, they are ignored for statements such as *Note `SELECT': select. and *Note `EXPLAIN': explain. that otherwise would use them. `ENABLE KEYS' and `DISABLE KEYS' were not supported for partitioned tables prior to MySQL 5.1.11. * If *Note `ALTER TABLE': alter-table. for an `InnoDB' table results in changes to column values (for example, because a column is truncated), `InnoDB''s `FOREIGN KEY' constraint checks do not notice possible violations caused by changing the values. * The `FOREIGN KEY' and `REFERENCES' clauses are supported by the `InnoDB' storage engine, which implements `ADD [CONSTRAINT [SYMBOL]] FOREIGN KEY (...) REFERENCES ... (...)'. See *Note innodb-foreign-key-constraints::. For other storage engines, the clauses are parsed but ignored. The `CHECK' clause is parsed but ignored by all storage engines. See *Note create-table::. The reason for accepting but ignoring syntax clauses is for compatibility, to make it easier to port code from other SQL servers, and to run applications that create tables with references. See *Note differences-from-ansi::. *Important*: The inline `REFERENCES' specifications where the references are defined as part of the column specification are silently ignored by `InnoDB'. InnoDB only accepts `REFERENCES' clauses defined as part of a separate `FOREIGN KEY' specification. *Note*: Partitioned tables do not support foreign keys. See *Note partitioning-limitations::, for more information. * `InnoDB' supports the use of *Note `ALTER TABLE': alter-table. to drop foreign keys: ALTER TABLE TBL_NAME DROP FOREIGN KEY FK_SYMBOL; For more information, see *Note innodb-foreign-key-constraints::. * You cannot add a foreign key and drop a foreign key in separate clauses of a single *Note `ALTER TABLE': alter-table. statement. You must use separate statements. * For an `InnoDB' table that is created with its own tablespace in an `.ibd' file, that file can be discarded and imported. To discard the `.ibd' file, use this statement: ALTER TABLE TBL_NAME DISCARD TABLESPACE; This deletes the current `.ibd' file, so be sure that you have a backup first. Attempting to access the table while the tablespace file is discarded results in an error. To import the backup `.ibd' file back into the table, copy it into the database directory, and then issue this statement: ALTER TABLE TBL_NAME IMPORT TABLESPACE; The tablespace file must have been created on the server into which it is imported later. See *Note innodb-multiple-tablespaces::. * Pending *Note `INSERT DELAYED': insert-delayed. statements are lost if a table is write locked and *Note `ALTER TABLE': alter-table. is used to modify the table structure. * If you want to change the table default character set and all character columns (*Note `CHAR': char, *Note `VARCHAR': char, *Note `TEXT': blob.) to a new character set, use a statement like this: ALTER TABLE TBL_NAME CONVERT TO CHARACTER SET CHARSET_NAME; For a column that has a data type of *Note `VARCHAR': char. or one of the *Note `TEXT': blob. types, `CONVERT TO CHARACTER SET' will change the data type as necessary to ensure that the new column is long enough to store as many characters as the original column. For example, a *Note `TEXT': blob. column has two length bytes, which store the byte-length of values in the column, up to a maximum of 65,535. For a `latin1' *Note `TEXT': blob. column, each character requires a single byte, so the column can store up to 65,535 characters. If the column is converted to `utf8', each character might require up to three bytes, for a maximum possible length of 3 x 65,535 = 196,605 bytes. That length will not fit in a *Note `TEXT': blob. column's length bytes, so MySQL will convert the data type to *Note `MEDIUMTEXT': blob, which is the smallest string type for which the length bytes can record a value of 196,605. Similarly, a *Note `VARCHAR': char. column might be converted to *Note `MEDIUMTEXT': blob. To avoid data type changes of the type just described, do not use `CONVERT TO CHARACTER SET'. Instead, use `MODIFY' to change individual columns. For example: ALTER TABLE t MODIFY latin1_text_col TEXT CHARACTER SET utf8; ALTER TABLE t MODIFY latin1_varchar_col VARCHAR(M) CHARACTER SET utf8; If you specify `CONVERT TO CHARACTER SET binary', the *Note `CHAR': char, *Note `VARCHAR': char, and *Note `TEXT': blob. columns are converted to their corresponding binary string types (*Note `BINARY': binary-varbinary, *Note `VARBINARY': binary-varbinary, *Note `BLOB': blob.). This means that the columns no longer will have a character set and a subsequent `CONVERT TO' operation will not apply to them. If CHARSET_NAME is `DEFAULT', the database character set is used. *Warning*: The `CONVERT TO' operation converts column values between the character sets. This is _not_ what you want if you have a column in one character set (like `latin1') but the stored values actually use some other, incompatible character set (like `utf8'). In this case, you have to do the following for each such column: ALTER TABLE t1 CHANGE c1 c1 BLOB; ALTER TABLE t1 CHANGE c1 c1 TEXT CHARACTER SET utf8; The reason this works is that there is no conversion when you convert to or from *Note `BLOB': blob. columns. To change only the _default_ character set for a table, use this statement: ALTER TABLE TBL_NAME DEFAULT CHARACTER SET CHARSET_NAME; The word `DEFAULT' is optional. The default character set is the character set that is used if you do not specify the character set for columns that you add to a table later (for example, with `ALTER TABLE ... ADD column'). With the *Note `mysql_info()': mysql-info. C API function, you can find out how many rows were copied, and (when `IGNORE' is used) how many rows were deleted due to duplication of unique key values. See *Note mysql-info::.  File: manual.info, Node: alter-table-partition-operations, Next: alter-table-online-operations, Prev: alter-table, Up: alter-table 13.1.7.1 `ALTER TABLE' Partition Operations ........................................... A number of partitioning-related extensions to *Note `ALTER TABLE': alter-table. were added in MySQL 5.1.5. These can be used with partitioned tables for repartitioning, for adding, dropping, merging, and splitting partitions, and for performing partitioning maintenance. * Simply using a PARTITION_OPTIONS clause with *Note `ALTER TABLE': alter-table. on a partitioned table repartitions the table according to the partitioning scheme defined by the PARTITION_OPTIONS. This clause always begins with `PARTITION BY', and follows the same syntax and other rules as apply to the PARTITION_OPTIONS clause for *Note `CREATE TABLE': create-table. (see *Note create-table::, for more detailed information), and can also be used to partition an existing table that is not already partitioned. For example, consider a (nonpartitioned) table defined as shown here: CREATE TABLE t1 ( id INT, year_col INT ); This table can be partitioned by `HASH', using the `id' column as the partitioning key, into 8 partitions by means of this statement: ALTER TABLE t1 PARTITION BY HASH(id) PARTITIONS 8; The table that results from using an `ALTER TABLE ... PARTITION BY' statement must follow the same rules as one created using `CREATE TABLE ... PARTITION BY'. This includes the rules governing the relationship between any unique keys (including any primary key) that the table might have, and the column or columns used in the partitioning expression, as discussed in *Note partitioning-limitations-partitioning-keys-unique-keys::. The `CREATE TABLE ... PARTITION BY' rules for specifying the number of partitions also apply to `ALTER TABLE ... PARTITION BY'. `ALTER TABLE ... PARTITION BY' became available in MySQL 5.1.6. The PARTITION_DEFINITION clause for `ALTER TABLE ADD PARTITION' supports the same options as the clause of the same name for the *Note `CREATE TABLE': create-table. statement. (See *Note create-table::, for the syntax and description.) Suppose that you have the partitioned table created as shown here: CREATE TABLE t1 ( id INT, year_col INT ) PARTITION BY RANGE (year_col) ( PARTITION p0 VALUES LESS THAN (1991), PARTITION p1 VALUES LESS THAN (1995), PARTITION p2 VALUES LESS THAN (1999) ); You can add a new partition `p3' to this table for storing values less than `2002' as follows: ALTER TABLE t1 ADD PARTITION (PARTITION p3 VALUES LESS THAN (2002)); `DROP PARTITION' can be used to drop one or more `RANGE' or `LIST' partitions. This statement cannot be used with `HASH' or `KEY' partitions; instead, use `COALESCE PARTITION' (see below). Any data that was stored in the dropped partitions named in the PARTITION_NAMES list is discarded. For example, given the table `t1' defined previously, you can drop the partitions named `p0' and `p1' as shown here: ALTER TABLE t1 DROP PARTITION p0, p1; *Note*: `DROP PARTITION' does not work with tables that use the *Note `NDBCLUSTER': mysql-cluster. storage engine. See *Note partitioning-management-range-list::, and *Note mysql-cluster-limitations::. `ADD PARTITION' and `DROP PARTITION' do not currently support `IF [NOT] EXISTS'. It is also not possible to rename a partition or a partitioned table. Instead, if you wish to rename a partition, you must drop and re-create the partition; if you wish to rename a partitioned table, you must instead drop all partitions, rename the table, and then add back the partitions that were dropped. `COALESCE PARTITION' can be used with a table that is partitioned by `HASH' or `KEY' to reduce the number of partitions by NUMBER. Suppose that you have created table `t2' using the following definition: CREATE TABLE t2 ( name VARCHAR (30), started DATE ) PARTITION BY HASH( YEAR(started) ) PARTITIONS 6; You can reduce the number of partitions used by `t2' from 6 to 4 using the following statement: ALTER TABLE t2 COALESCE PARTITION 2; The data contained in the last NUMBER partitions will be merged into the remaining partitions. In this case, partitions 4 and 5 will be merged into the first 4 partitions (the partitions numbered 0, 1, 2, and 3). To change some but not all the partitions used by a partitioned table, you can use `REORGANIZE PARTITION'. This statement can be used in several ways: * To merge a set of partitions into a single partition. This can be done by naming several partitions in the PARTITION_NAMES list and supplying a single definition for PARTITION_DEFINITION. * To split an existing partition into several partitions. You can accomplish this by naming a single partition for PARTITION_NAMES and providing multiple PARTITION_DEFINITIONS. * To change the ranges for a subset of partitions defined using `VALUES LESS THAN' or the value lists for a subset of partitions defined using `VALUES IN'. * This statement may also be used without the `PARTITION_NAMES INTO (PARTITION_DEFINITIONS)' option on tables that are automatically partitioned using `HASH' partitioning to force redistribution of data. (Currently, only *Note `NDBCLUSTER': mysql-cluster. tables are automatically partitioned in this way.) This is useful in MySQL Cluster NDB 6.4.0 and later where, after you have added new MySQL Cluster data nodes online to an existing MySQL Cluster, you wish to redistribute existing MySQL Cluster table data to the new data nodes. In such cases, you should invoke the satement with the `ONLINE' option; in words words, as shown here: ALTER ONLINE TABLE TABLE REORGANIZE PARTITION; You cannot perform other DDL concurrently with online table reorganization--that is, no other DDL statements can be issued while an `ALTER ONLINE TABLE ... REORGANIZE PARTITION' statement is executing. For more information about adding MySQL Cluster data nodes online, see *Note mysql-cluster-online-add-node::. Attempting to use `REORGANIZE PARTITION' without the `PARTITION_NAMES INTO (PARTITION_DEFINITIONS)' option on explicitly partitioned tables results in the error `REORGANIZE PARTITION without parameters can only be used on auto-partitioned tables using HASH partitioning'. *Note*: For partitions that have not been explicitly named, MySQL automatically provides the default names `p0', `p1', `p2', and so on. As of MySQL 5.1.7, the same is true with regard to subpartitions. For more detailed information about and examples of `ALTER TABLE ... REORGANIZE PARTITION' statements, see *Note partitioning-management-range-list::. * Several additional options were introduced in MySQL 5.1.5 for providing partition maintenance and repair functionality analogous to that implemented for nonpartitioned tables by statements such as *Note `CHECK TABLE': check-table. and *Note `REPAIR TABLE': repair-table. (which are also supported for partitioned tables, beginning with MySQL 5.1.27--see note at the end of this item). These include `ANALYZE PARTITION', `CHECK PARTITION', `OPTIMIZE PARTITION', `REBUILD PARTITION', and `REPAIR PARTITION'. Each of these options takes a PARTITION_NAMES clause consisting of one or more names of partitions, separated by commas. The partitions must already exist in the table to be altered. You can also use the `ALL' keyword in place of PARTITION_NAMES, in which case the statement acts on all partitions in the table. For more information and examples, see *Note partitioning-maintenance::. The `ANALYZE PARTITION', `CHECK PARTITION', `OPTIMIZE PARTITION', and `REPAIR PARTITION' options were disabled in MySQL 5.1.24, and re-enabled in MySQL 5.1.27. (Bug#20129) They are not supported for tables which are not partitioned; beginning with MySQL 5.1.31, they are not permitted for such tables. *Note*: Beginning with MySQL 5.1.27, you can use the statements *Note `ANALYZE TABLE': analyze-table, *Note `CHECK TABLE': check-table, *Note `OPTIMIZE TABLE': optimize-table, and *Note `REPAIR TABLE': repair-table. on partitioned tables. See *Note table-maintenance-sql::, for more information. * `REMOVE PARTITIONING' was introduced in MySQL 5.1.8 for the purpose of removing a table's partitioning without otherwise affecting the table or its data. (Previously, this was done using the `ENGINE' option.) This option can be combined with other *Note `ALTER TABLE': alter-table. options such as those used to add, drop, or rename drop columns or indexes. * In MySQL 5.1.7 and earlier, using the `ENGINE' option with *Note `ALTER TABLE': alter-table. caused any partitioning that a table might have had to be removed. Beginning with MySQL 5.1.8, this option merely changes the storage engine used by the table and no longer affects partitioning in any way. Only a single instance of any one of the following options can be used in a given *Note `ALTER TABLE': alter-table. statement: `PARTITION BY', `ADD PARTITION', `DROP PARTITION', `TRUNCATE PARTITION', `REORGANIZE PARTITION', or `COALESCE PARTITION', `ANALYZE PARTITION', `CHECK PARTITION', `OPTIMIZE PARTITION', `REBUILD PARTITION', `REMOVE PARTITIONING'. For example, the following two statements are invalid: ALTER TABLE t1 ANALYZE PARTITION p1, ANALYZE PARTITION p2; ALTER TABLE t1 ANALYZE PARTITION p1, CHECK PARTITION p2; In the first case, you can analyze partitions `p1' and `p2' of table `t1' concurrently using a single statement with a single `ANALYZE PARTITION' option that lists both of the partitions to be analyzed, like this: ALTER TABLE t1 ANALYZE PARTITION p1, p2; In the second case, it is not possible to perform `ANALYZE' and `CHECK' operations on different partitions of the same table concurrently. Instead, you must issue two separate statements, like this: ALTER TABLE t1 ANALYZE PARTITION p1; ALTER TABLE t1 CHECK PARTITION p2;  File: manual.info, Node: alter-table-online-operations, Next: alter-table-examples, Prev: alter-table-partition-operations, Up: alter-table 13.1.7.2 `ALTER TABLE' Online Operations ........................................ Beginning with MySQL 5.1.17, operations that add and drop indexes on variable-width columns of *Note `NDBCLUSTER': mysql-cluster. tables occur online, without any table copying and without blocking concurrent DML actions for most of their duration. The `ONLINE' keyword can be used to perform online `ADD COLUMN', `ADD INDEX' (including `CREATE INDEX' statements), and `DROP INDEX' operations on *Note `NDBCLUSTER': mysql-cluster. tables beginning with MySQL Cluster NDB 6.2.5 and MySQL Cluster NDB 6.3.3. Online renaming of *Note `NDBCLUSTER': mysql-cluster. tables is also supported. Currently you cannot add disk-based columns to *Note `NDBCLUSTER': mysql-cluster. tables online. This means that, if you wish to add an in-memory column to an *Note `NDBCLUSTER': mysql-cluster. table that uses a table-level `STORAGE DISK' option, you must declare the new column as using memory-based storage explicitly. For example--assuming that you have already created tablespace `ts1'--suppose that you create table `t1' as follows: mysql> CREATE TABLE t1 ( > c1 INT NOT NULL PRIMARY KEY, > c2 VARCHAR(30) > ) > TABLESPACE ts1 STORAGE DISK > ENGINE NDBCLUSTER; Query OK, 0 rows affected (1.73 sec) Records: 0 Duplicates: 0 Warnings: 0 You can add a new in-memory column to this table online as shown here: mysql> ALTER ONLINE TABLE t1 ADD COLUMN c3 INT COLUMN_FORMAT DYNAMIC STORAGE MEMORY; Query OK, 0 rows affected (1.25 sec) Records: 0 Duplicates: 0 Warnings: 0 This statement fails if the `STORAGE MEMORY' option is omitted: mysql> ALTER ONLINE TABLE t1 ADD COLUMN c3 INT COLUMN_FORMAT DYNAMIC; `ERROR 1235 (42000): This version of MySQL doesn't yet support 'ALTER ONLINE TABLE t1 ADD COLUMN c3 INT COLUMN_FORMAT DYNAMIC'' If you omit the `COLUMN_FORMAT DYNAMIC' option, the dynamic column format is employed automatically, but a warning is issued, as shown here: mysql> ALTER ONLINE TABLE t1 ADD COLUMN c3 INT STORAGE MEMORY; Query OK, 0 rows affected, 1 warning (1.17 sec) Records: 0 Duplicates: 0 Warnings: 0 mysql> SHOW WARNINGS; +---------+------+---------------------------------------------------------------+ | Level | Code | Message | +---------+------+---------------------------------------------------------------+ | Warning | 1478 | Converted FIXED field to DYNAMIC to enable on-line ADD COLUMN | +---------+------+---------------------------------------------------------------+ 1 row in set (0.00 sec) mysql> SHOW CREATE TABLE t1\G *************************** 1. row *************************** Table: t1 Create Table: CREATE TABLE `t1` ( `c1` int(11) NOT NULL, `c2` varchar(30) DEFAULT NULL, `c3` int(11) /*!50120 STORAGE MEMORY */ /*!50120 COLUMN_FORMAT DYNAMIC */ DEFAULT NULL, `t4` int(11) /*!50120 STORAGE MEMORY */ DEFAULT NULL, PRIMARY KEY (`c1`) ) /*!50100 TABLESPACE ts_1 STORAGE DISK */ ENGINE=ndbcluster DEFAULT CHARSET=latin1 1 row in set (0.03 sec) Prior to MySQL Cluster NDB 6.2.17, 6.3.23, and 6.4.3, adding in-memory columns to tables that were created using a table-level or column-level `STORAGE DISK' option did not work correctly. (Bug#42549) *Note*: The `STORAGE' and `COLUMN_FORMAT' keywords are supported only in MySQL Cluster; in any other version of MySQL, attempting to use either of these keywords in a *Note `CREATE TABLE': create-table. or `ALTER TABLE' statement results in an error. Online operations are noncopying; that is, they do not require that indexes be re-created. They do not lock the table being altered from access my other API nodes in a MySQL Cluster (but see `Limitations' later in this section). Such operations do not require single user mode for *Note `NDBCLUSTER': mysql-cluster. table alterations made in a cluster with multiple API nodes; transactions can continue uninterrupted during online DDL operations. In MySQL Cluster NDB 7.0 and later, it is also possible to use the statement `ALTER ONLINE TABLE ... REORGANIZE PARTITION' with no `PARTITION_NAMES INTO (PARTITION_DEFINITIONS)' option on *Note `NDBCLUSTER': mysql-cluster. tables. This can be used to redistribute MySQL Cluster data among new data nodes that have been added to the cluster online. More information about this statement is given later in this section. For more information about adding data nodes online to a MySQL Cluster, see *Note mysql-cluster-online-add-node::. Prior to MySQL Cluster NDB 6.4.3, `ALTER ONLINE TABLE ... REORGANIZE PARTITION' with no `PARTITION_NAMES INTO (PARTITION_DEFINITIONS)' option did not work correctly with Disk Data tables or with in-memory *Note `NDBCLUSTER': mysql-cluster. tables having one or more disk-based columns. (Bug#42549) The `ONLINE' and `OFFLINE' keywords are supported only in MySQL Cluster NDB 6.2, 6.3, 7.0 (beginning with versions 6.2.5, 6.3.3, and 6.4.0), and later MySQL Cluster release series. In other versions of MySQL (5.1.17 and later): 1. The server determines automatically whether an `ADD INDEX' or `DROP INDEX' operation can be (and is) performed online or offline; if the column is of a variable-width data type, then the operation is performed online. It is not possible to override the server behavior in this regard. 2. Attempting to use the `ONLINE' or `OFFLINE' keyword in an *Note `ALTER TABLE': alter-table. statement results in an error. * Limitations of *Note `NDBCLUSTER': mysql-cluster. online operations * Online *Note `ALTER TABLE': alter-table. operations that add columns are subject to the following limitations: * The table being altered is not locked with respect to API nodes other than the one on which an online *Note `ALTER TABLE': alter-table, `ADD COLUMN', `CREATE INDEX', or `DROP INDEX' statement is run. However, the table is locked against any other operations originating on the _same_ API node while the online operation is being executed. * The table to be altered must have an explicit primary key; the hidden primary key created by the *Note `NDBCLUSTER': mysql-cluster. storage engine is not sufficient for this purpose. Columns to be added online must meet the following criteria: * The columns must be dynamic; that is, it must be possible to create them using `COLUMN_FORMAT DYNAMIC'. * The columns must permit `NULL' values and not have any explicit default value other than `NULL'. Columns added online are automatically created as `DEFAULT NULL', as can be seen here: mysql> CREATE TABLE t1 ( > c1 INT NOT NULL AUTO_INCREMENT PRIMARY KEY > ) ENGINE=NDBCLUSTER; Query OK, 0 rows affected (1.44 sec) mysql> ALTER ONLINE TABLE t1 > ADD COLUMN c2 INT, > ADD COLUMN c3 INT; Query OK, 0 rows affected, 2 warnings (0.93 sec) mysql> SHOW CREATE TABLE t2\G *************************** 1. row *************************** Table: t2 Create Table: CREATE TABLE `t2` ( `c1` int(11) NOT NULL AUTO_INCREMENT, `c2` int(11) DEFAULT NULL, `c3` int(11) DEFAULT NULL, PRIMARY KEY (`c1`) ) ENGINE=ndbcluster DEFAULT CHARSET=latin1 1 row in set (0.00 sec) * The columns must be added following any existing columns. If you attempt to add a column online before any existing columns or using the `FIRST' keyword, the statement fails with an error. In addition, existing table columns cannot be reordered online. * The storage engine used by the table cannot be changed online. The preceding limitations do not apply to operations that merely rename tables or columns. If the storage engine supports online *Note `ALTER TABLE': alter-table, then fixed-format columns will be converted to dynamic when columns are added online, or when indexes are created or dropped online, as shown here: mysql> CREATE TABLE t1 ( > c1 INT NOT NULL AUTO_INCREMENT PRIMARY KEY > ) ENGINE=NDBCLUSTER; Query OK, 0 rows affected (1.44 sec) mysql> ALTER ONLINE TABLE t1 ADD COLUMN c2 INT, ADD COLUMN c3 INT; Query OK, 0 rows affected, 2 warnings (0.93 sec) Records: 0 Duplicates: 0 Warnings: 0 mysql> SHOW WARNINGS; +---------+------+---------------------------------------------------------------+ | Level | Code | Message | +---------+------+---------------------------------------------------------------+ | Warning | 1475 | Converted FIXED field to DYNAMIC to enable on-line ADD COLUMN | | Warning | 1475 | Converted FIXED field to DYNAMIC to enable on-line ADD COLUMN | +---------+------+---------------------------------------------------------------+ 2 rows in set (0.00 sec) *Note*: Existing columns, including the table's primary key, need not be dynamic; only the column or columns to be added online must be dynamic. mysql> CREATE TABLE t2 ( > c1 INT NOT NULL AUTO_INCREMENT PRIMARY KEY COLUMN_FORMAT FIXED > ) ENGINE=NDBCLUSTER; Query OK, 0 rows affected (2.10 sec) mysql> ALTER ONLINE TABLE t2 ADD COLUMN c2 INT; Query OK, 0 rows affected, 1 warning (0.78 sec) Records: 0 Duplicates: 0 Warnings: 0 mysql> SHOW WARNINGS; +---------+------+---------------------------------------------------------------+ | Level | Code | Message | +---------+------+---------------------------------------------------------------+ | Warning | 1475 | Converted FIXED field to DYNAMIC to enable on-line ADD COLUMN | +---------+------+---------------------------------------------------------------+ 1 row in set (0.00 sec) Columns are not converted from `FIXED' to `DYNAMIC' column format by renaming operations. For more information about `COLUMN_FORMAT', see *Note create-table::. * When used with MySQL Cluster Disk Data tables, it is not possible to change the storage type (`DISK' or `MEMORY') of a column online. This means, that when you add or drop an index in such a way that the operation would be performed online, and you want the storage type of the column or columns to be changed, you must use the `OFFLINE' keyword in the statement that adds or drops the index. * Online `DROP COLUMN' operations are not supported. * A given online *Note `ALTER TABLE': alter-table. can use only one of `ADD COLUMN', `ADD INDEX', or `DROP INDEX'. One or more columns can be added online in a single statement; only one index may be created or dropped online in a single statement. The `KEY', `CONSTRAINT', and `IGNORE' keywords are supported in *Note `ALTER TABLE': alter-table. statements using the `ONLINE' keyword.  File: manual.info, Node: alter-table-examples, Prev: alter-table-online-operations, Up: alter-table 13.1.7.3 `ALTER TABLE' Examples ............................... Begin with a table `t1' that is created as shown here: CREATE TABLE t1 (a INTEGER,b CHAR(10)); To rename the table from `t1' to `t2': ALTER TABLE t1 RENAME t2; To change column `a' from *Note `INTEGER': numeric-types. to `TINYINT NOT NULL' (leaving the name the same), and to change column `b' from `CHAR(10)' to `CHAR(20)' as well as renaming it from `b' to `c': ALTER TABLE t2 MODIFY a TINYINT NOT NULL, CHANGE b c CHAR(20); To add a new *Note `TIMESTAMP': datetime. column named `d': ALTER TABLE t2 ADD d TIMESTAMP; To add an index on column `d' and a `UNIQUE' index on column `a': ALTER TABLE t2 ADD INDEX (d), ADD UNIQUE (a); To remove column `c': ALTER TABLE t2 DROP COLUMN c; To add a new `AUTO_INCREMENT' integer column named `c': ALTER TABLE t2 ADD c INT UNSIGNED NOT NULL AUTO_INCREMENT, ADD PRIMARY KEY (c); We indexed `c' (as a `PRIMARY KEY') because `AUTO_INCREMENT' columns must be indexed, and we declare `c' as `NOT NULL' because primary key columns cannot be `NULL'. For *Note `NDB': mysql-cluster. tables, it is also possible to change the storage type used for a table or column. For example, consider an *Note `NDB': mysql-cluster. table created as shown here: mysql> CREATE TABLE t1 (c1 INT) TABLESPACE ts_1 ENGINE NDB; Query OK, 0 rows affected (1.27 sec) To convert this table to disk-based storage, you can use the following *Note `ALTER TABLE': alter-table. statement: mysql> ALTER TABLE t1 TABLESPACE ts_1 STORAGE DISK; Query OK, 0 rows affected (2.99 sec) Records: 0 Duplicates: 0 Warnings: 0 mysql> SHOW CREATE TABLE t1\G *************************** 1. row *************************** Table: t1 Create Table: CREATE TABLE `t1` ( `c1` int(11) DEFAULT NULL ) /*!50100 TABLESPACE ts_1 STORAGE DISK */ ENGINE=ndbcluster DEFAULT CHARSET=latin1 1 row in set (0.01 sec) It is not necessary that the tablespace was referenced when the table was originally created; however, the tablespace must be referenced by the *Note `ALTER TABLE': alter-table.: mysql> CREATE TABLE t2 (c1 INT) ts_1 ENGINE NDB; Query OK, 0 rows affected (1.00 sec) mysql> ALTER TABLE t2 STORAGE DISK; `ERROR 1005 (HY000): Can't create table 'c.#sql-1750_3' (errno: 140)' mysql> ALTER TABLE t2 TABLESPACE ts_1 STORAGE DISK; Query OK, 0 rows affected (3.42 sec) Records: 0 Duplicates: 0 Warnings: 0 mysql> SHOW CREATE TABLE t2\G *************************** 1. row *************************** Table: t1 Create Table: CREATE TABLE `t2` ( `c1` int(11) DEFAULT NULL ) /*!50100 TABLESPACE ts_1 STORAGE DISK */ ENGINE=ndbcluster DEFAULT CHARSET=latin1 1 row in set (0.01 sec) To change the storage type of an individual column, you can use `ALTER TABLE ... MODIFY [COLUMN]'. For example, suppose you create a MySQL Cluster Disk Data table with two columns, using this *Note `CREATE TABLE': create-table. statement: mysql> CREATE TABLE t3 (c1 INT, c2 INT) -> TABLESPACE ts_1 STORAGE DISK ENGINE NDB; Query OK, 0 rows affected (1.34 sec) To change column `c2' from disk-based to in-memory storage, include a STORAGE MEMORY clause in the column definition used by the ALTER TABLE statement, as shown here: mysql> ALTER TABLE t3 MODIFY c2 INT STORAGE MEMORY; Query OK, 0 rows affected (3.14 sec) Records: 0 Duplicates: 0 Warnings: 0 You can make an in-memory column into a disk-based column by using `STORAGE DISK' in a similar fashion. Column `c1' uses disk-based storage, since this is the default for the table (determined by the table-level `STORAGE DISK' clause in the *Note `CREATE TABLE': create-table. statement). However, column `c2' uses in-memory storage, as can be seen here in the output of SHOW *Note `CREATE TABLE': create-table.: mysql> SHOW CREATE TABLE t3\G *************************** 1. row *************************** Table: t3 Create Table: CREATE TABLE `t3` ( `c1` int(11) DEFAULT NULL, `c2` int(11) /*!50120 STORAGE MEMORY */ DEFAULT NULL ) /*!50100 TABLESPACE ts_1 STORAGE DISK */ ENGINE=ndbcluster DEFAULT CHARSET=latin1 1 row in set (0.02 sec) When you add an `AUTO_INCREMENT' column, column values are filled in with sequence numbers automatically. For `MyISAM' tables, you can set the first sequence number by executing `SET INSERT_ID=VALUE' before *Note `ALTER TABLE': alter-table. or by using the `AUTO_INCREMENT=VALUE' table option. See *Note server-system-variables::. With `MyISAM' tables, if you do not change the `AUTO_INCREMENT' column, the sequence number is not affected. If you drop an `AUTO_INCREMENT' column and then add another `AUTO_INCREMENT' column, the numbers are resequenced beginning with 1. When replication is used, adding an `AUTO_INCREMENT' column to a table might not produce the same ordering of the rows on the slave and the master. This occurs because the order in which the rows are numbered depends on the specific storage engine used for the table and the order in which the rows were inserted. If it is important to have the same order on the master and slave, the rows must be ordered before assigning an `AUTO_INCREMENT' number. Assuming that you want to add an `AUTO_INCREMENT' column to the table `t1', the following statements produce a new table `t2' identical to `t1' but with an `AUTO_INCREMENT' column: CREATE TABLE t2 (id INT AUTO_INCREMENT PRIMARY KEY) SELECT * FROM t1 ORDER BY col1, col2; This assumes that the table `t1' has columns `col1' and `col2'. This set of statements will also produce a new table `t2' identical to `t1', with the addition of an `AUTO_INCREMENT' column: CREATE TABLE t2 LIKE t1; ALTER TABLE t2 ADD id INT AUTO_INCREMENT PRIMARY KEY; INSERT INTO t2 SELECT * FROM t1 ORDER BY col1, col2; *Important*: To guarantee the same ordering on both master and slave, _all_ columns of `t1' must be referenced in the `ORDER BY' clause. Regardless of the method used to create and populate the copy having the `AUTO_INCREMENT' column, the final step is to drop the original table and then rename the copy: DROP t1; ALTER TABLE t2 RENAME t1;  File: manual.info, Node: alter-tablespace, Next: alter-view, Prev: alter-table, Up: sql-syntax-data-definition 13.1.8 `ALTER TABLESPACE' Syntax -------------------------------- ALTER TABLESPACE TABLESPACE_NAME {ADD|DROP} DATAFILE 'FILE_NAME' [INITIAL_SIZE [=] SIZE] [WAIT] ENGINE [=] ENGINE_NAME This statement can be used either to add a new data file, or to drop a data file from a tablespace. The `ADD DATAFILE' variant enables you to specify an initial size using an `INITIAL_SIZE' clause, where SIZE is measured in bytes; the default value is `128M' (128 megabytes). You may optionally follow this integer value with a one-letter abbreviation for an order of magnitude, similar to those used in `my.cnf'. Generally, this is one of the letters `M' (for megabytes) or `G' (for gigabytes). *Note*: All MySQL Cluster Disk Data objects share the same namespace. This means that _each Disk Data object_ must be uniquely named (and not merely each Disk Data object of a given type). For example, you cannot have a tablespace and an data file with the same name, or an undo log file and a with the same name. Prior to MySQL Cluster NDB 6.2.17, 6.3.23, and 6.4.3, path and file names for data files could not be longer than 128 characters. (Bug#31770) On 32-bit systems, the maximum supported value for `INITIAL_SIZE' is `4G'. (Bug#29186) `INITIAL_SIZE' is rounded as for *Note `CREATE TABLESPACE': create-tablespace. Beginning with MySQL Cluster NDB 6.2.19, MySQL Cluster NDB 6.3.32, MySQL Cluster NDB 7.0.13, and MySQL Cluster NDB 7.1.2, this rounding is done explicitly (also as with *Note `CREATE TABLESPACE': create-tablespace.). Once a data file has been created, its size cannot be changed; however, you can add more data files to the tablespace using additional `ALTER TABLESPACE ... ADD DATAFILE' statements. Using `DROP DATAFILE' with *Note `ALTER TABLESPACE': alter-tablespace. drops the data file 'FILE_NAME' from the tablespace. This file must already have been added to the tablespace using *Note `CREATE TABLESPACE': create-tablespace. or *Note `ALTER TABLESPACE': alter-tablespace.; otherwise an error will result. Both `ALTER TABLESPACE ... ADD DATAFILE' and `ALTER TABLESPACE ... DROP DATAFILE' require an `ENGINE' clause which specifies the storage engine used by the tablespace. In MySQL 5.1, the only accepted values for ENGINE_NAME are *Note `NDB': mysql-cluster. and *Note `NDBCLUSTER': mysql-cluster. `WAIT' is parsed but otherwise ignored, and so has no effect in MySQL 5.1. It is intended for future expansion. When `ALTER TABLESPACE ... ADD DATAFILE' is used with `ENGINE = NDB', a data file is created on each Cluster data node. You can verify that the data files were created and obtain information about them by querying the *Note `INFORMATION_SCHEMA.FILES': files-table. table. For example, the following query shows all data files belonging to the tablespace named `newts': mysql> SELECT LOGFILE_GROUP_NAME, FILE_NAME, EXTRA -> FROM INFORMATION_SCHEMA.FILES -> WHERE TABLESPACE_NAME = 'newts' AND FILE_TYPE = 'DATAFILE'; +--------------------+--------------+----------------+ | LOGFILE_GROUP_NAME | FILE_NAME | EXTRA | +--------------------+--------------+----------------+ | lg_3 | newdata.dat | CLUSTER_NODE=3 | | lg_3 | newdata.dat | CLUSTER_NODE=4 | | lg_3 | newdata2.dat | CLUSTER_NODE=3 | | lg_3 | newdata2.dat | CLUSTER_NODE=4 | +--------------------+--------------+----------------+ 2 rows in set (0.03 sec) See *Note files-table::. *Note `ALTER TABLESPACE': alter-tablespace. was added in MySQL 5.1.6. In MySQL 5.1, it is useful only with Disk Data storage for MySQL Cluster. See *Note mysql-cluster-disk-data::.  File: manual.info, Node: alter-view, Next: create-database, Prev: alter-tablespace, Up: sql-syntax-data-definition 13.1.9 `ALTER VIEW' Syntax -------------------------- ALTER [ALGORITHM = {UNDEFINED | MERGE | TEMPTABLE}] [DEFINER = { USER | CURRENT_USER }] [SQL SECURITY { DEFINER | INVOKER }] VIEW VIEW_NAME [(COLUMN_LIST)] AS SELECT_STATEMENT [WITH [CASCADED | LOCAL] CHECK OPTION] This statement changes the definition of a view, which must exist. The syntax is similar to that for *Note `CREATE VIEW': create-view. and the effect is the same as for *Note `CREATE OR REPLACE VIEW': create-view. See *Note create-view::. This statement requires the `CREATE VIEW' and `DROP' privileges for the view, and some privilege for each column referred to in the *Note `SELECT': select. statement. As of MySQL 5.1.23, *Note `ALTER VIEW': alter-view. is permitted only to the definer or users with the `SUPER' privilege.  File: manual.info, Node: create-database, Next: create-event, Prev: alter-view, Up: sql-syntax-data-definition 13.1.10 `CREATE DATABASE' Syntax -------------------------------- CREATE {DATABASE | SCHEMA} [IF NOT EXISTS] DB_NAME [CREATE_SPECIFICATION] ... CREATE_SPECIFICATION: [DEFAULT] CHARACTER SET [=] CHARSET_NAME | [DEFAULT] COLLATE [=] COLLATION_NAME *Note `CREATE DATABASE': create-database. creates a database with the given name. To use this statement, you need the `CREATE' privilege for the database. *Note `CREATE SCHEMA': create-database. is a synonym for *Note `CREATE DATABASE': create-database. An error occurs if the database exists and you did not specify `IF NOT EXISTS'. CREATE_SPECIFICATION options specify database characteristics. Database characteristics are stored in the `db.opt' file in the database directory. The `CHARACTER SET' clause specifies the default database character set. The `COLLATE' clause specifies the default database collation. *Note charset::, discusses character set and collation names. A database in MySQL is implemented as a directory containing files that correspond to tables in the database. Because there are no tables in a database when it is initially created, the *Note `CREATE DATABASE': create-database. statement creates only a directory under the MySQL data directory and the `db.opt' file. Rules for permissible database names are given in *Note identifiers::. If a database name contains special characters, the name for the database directory contains encoded versions of those characters as described in *Note identifier-mapping::. If you manually create a directory under the data directory (for example, with `mkdir'), the server considers it a database directory and it shows up in the output of *Note `SHOW DATABASES': show-databases. You can also use the *Note `mysqladmin': mysqladmin. program to create databases. See *Note mysqladmin::.  File: manual.info, Node: create-event, Next: create-function, Prev: create-database, Up: sql-syntax-data-definition 13.1.11 `CREATE EVENT' Syntax ----------------------------- CREATE [DEFINER = { USER | CURRENT_USER }] EVENT [IF NOT EXISTS] EVENT_NAME ON SCHEDULE SCHEDULE [ON COMPLETION [NOT] PRESERVE] [ENABLE | DISABLE | DISABLE ON SLAVE] [COMMENT 'COMMENT'] DO EVENT_BODY; SCHEDULE: AT TIMESTAMP [+ INTERVAL INTERVAL] ... | EVERY INTERVAL [STARTS TIMESTAMP [+ INTERVAL interval] ...] [ENDS TIMESTAMP [+ INTERVAL interval] ...] INTERVAL: QUANTITY {YEAR | QUARTER | MONTH | DAY | HOUR | MINUTE | WEEK | SECOND | YEAR_MONTH | DAY_HOUR | DAY_MINUTE | DAY_SECOND | HOUR_MINUTE | HOUR_SECOND | MINUTE_SECOND} This statement creates and schedules a new event. The event will not run unless the Event Scheduler is enabled. For information about checking Event Scheduler status and enabling it if necessary, see *Note events-configuration::. *Note `CREATE EVENT': create-event. requires the `EVENT' privilege for the schema in which the event is to be created. It might also require the `SUPER' privilege, depending on the `DEFINER' value, as described later in this section. The minimum requirements for a valid *Note `CREATE EVENT': create-event. statement are as follows: * The keywords *Note `CREATE EVENT': create-event. plus an event name, which uniquely identifies the event within a database schema. (Prior to MySQL 5.1.12, the event name needed to be unique only among events created by the same user within a schema.) * An `ON SCHEDULE' clause, which determines when and how often the event executes. * A *Note `DO': do. clause, which contains the SQL statement to be executed by an event. This is an example of a minimal *Note `CREATE EVENT': create-event. statement: CREATE EVENT myevent ON SCHEDULE AT CURRENT_TIMESTAMP + INTERVAL 1 HOUR DO UPDATE myschema.mytable SET mycol = mycol + 1; The previous statement creates an event named `myevent'. This event executes once--one hour following its creation--by running an SQL statement that increments the value of the `myschema.mytable' table's `mycol' column by 1. The EVENT_NAME must be a valid MySQL identifier with a maximum length of 64 characters. Event names are not case sensitive, so you cannot have two events named `myevent' and `MyEvent' in the same schema. In general, the rules governing event names are the same as those for names of stored routines. See *Note identifiers::. An event is associated with a schema. If no schema is indicated as part of EVENT_NAME, the default (current) schema is assumed. To create an event in a specific schema, qualify the event name with a schema using `SCHEMA_NAME.EVENT_NAME' syntax. The `DEFINER' clause specifies the MySQL account to be used when checking access privileges at event execution time. If a USER value is given, it should be a MySQL account specified as `'USER_NAME'@'HOST_NAME'' (the same format used in the *Note `GRANT': grant. statement), `CURRENT_USER', or `CURRENT_USER()'. The default `DEFINER' value is the user who executes the *Note `CREATE EVENT': create-event. statement. This is the same as specifying `DEFINER = CURRENT_USER' explicitly. If you specify the `DEFINER' clause, these rules determine the legal `DEFINER' user values: * If you do not have the `SUPER' privilege, the only legal USER value is your own account, either specified literally or by using `CURRENT_USER'. You cannot set the definer to some other account. * If you have the `SUPER' privilege, you can specify any syntactically legal account name. If the account does not actually exist, a warning is generated. * Although it is possible to create an event with a nonexistent `DEFINER' account, an error occurs at event execution time if the account does not exist. For more information about event security, see *Note stored-programs-security::. The `DEFINER' clause was added in MySQL 5.1.17. (Prior to MySQL 5.1.12, it was possible for two different users to create different events having the same name on the same database schema.) Within an event, the `CURRENT_USER()' function returns the account used to check privileges at event execution time, which is the `DEFINER' user. For information about user auditing within events, see *Note account-activity-auditing::. `IF NOT EXISTS' has the same meaning for *Note `CREATE EVENT': create-event. as for *Note `CREATE TABLE': create-table.: If an event named EVENT_NAME already exists in the same schema, no action is taken, and no error results. (However, a warning is generated in such cases.) The `ON SCHEDULE' clause determines when, how often, and for how long the EVENT_BODY defined for the event repeats. This clause takes one of two forms: * `AT TIMESTAMP' is used for a one-time event. It specifies that the event executes one time only at the date and time given by TIMESTAMP, which must include both the date and time, or must be an expression that resolves to a datetime value. You may use a value of either the *Note `DATETIME': datetime. or *Note `TIMESTAMP': datetime. type for this purpose. If the date is in the past, a warning occurs, as shown here: mysql> SELECT NOW(); +---------------------+ | NOW() | +---------------------+ | 2006-02-10 23:59:01 | +---------------------+ 1 row in set (0.04 sec) mysql> CREATE EVENT e_totals -> ON SCHEDULE AT '2006-02-10 23:59:00' -> DO INSERT INTO test.totals VALUES (NOW()); Query OK, 0 rows affected, 1 warning (0.00 sec) mysql> SHOW WARNINGS\G *************************** 1. row *************************** Level: Note Code: 1588 Message: Event execution time is in the past and ON COMPLETION NOT PRESERVE is set. The event was dropped immediately after creation. *Note `CREATE EVENT': create-event. statements which are themselves invalid--for whatever reason--fail with an error. You may use `CURRENT_TIMESTAMP' to specify the current date and time. In such a case, the event acts as soon as it is created. To create an event which occurs at some point in the future relative to the current date and time--such as that expressed by the phrase `three weeks from now'--you can use the optional clause `+ INTERVAL INTERVAL'. The INTERVAL portion consists of two parts, a quantity and a unit of time, and follows the same syntax rules that govern intervals used in the `DATE_ADD()' function (see *Note date-and-time-functions::. The units keywords are also the same, except that you cannot use any units involving microseconds when defining an event. With some interval types, complex time units may be used. For example, `two minutes and ten seconds' can be expressed as `+ INTERVAL '2:10' MINUTE_SECOND'. You can also combine intervals. For example, `AT CURRENT_TIMESTAMP + INTERVAL 3 WEEK + INTERVAL 2 DAY' is equivalent to `three weeks and two days from now'. Each portion of such a clause must begin with `+ INTERVAL'. * To repeat actions at a regular interval, use an `EVERY' clause. The `EVERY' keyword is followed by an INTERVAL as described in the previous discussion of the `AT' keyword. (`+ INTERVAL' is _not_ used with `EVERY'.) For example, `EVERY 6 WEEK' means `every six weeks'. Although `+ INTERVAL' clauses are not permitted in an `EVERY' clause, you can use the same complex time units permitted in a `+ INTERVAL'. An `EVERY' clause may contain an optional `STARTS' clause. `STARTS' is followed by a TIMESTAMP value that indicates when the action should begin repeating, and may also use `+ INTERVAL INTERVAL' to specify an amount of time `from now'. For example, `EVERY 3 MONTH STARTS CURRENT_TIMESTAMP + INTERVAL 1 WEEK' means `every three months, beginning one week from now'. Similarly, you can express `every two weeks, beginning six hours and fifteen minutes from now' as `EVERY 2 WEEK STARTS CURRENT_TIMESTAMP + INTERVAL '6:15' HOUR_MINUTE'. Not specifying `STARTS' is the same as using `STARTS CURRENT_TIMESTAMP'--that is, the action specified for the event begins repeating immediately upon creation of the event. An `EVERY' clause may contain an optional `ENDS' clause. The `ENDS' keyword is followed by a TIMESTAMP value that tells MySQL when the event should stop repeating. You may also use `+ INTERVAL INTERVAL' with `ENDS'; for instance, `EVERY 12 HOUR STARTS CURRENT_TIMESTAMP + INTERVAL 30 MINUTE ENDS CURRENT_TIMESTAMP + INTERVAL 4 WEEK' is equivalent to `every twelve hours, beginning thirty minutes from now, and ending four weeks from now'. Not using `ENDS' means that the event continues executing indefinitely. `ENDS' supports the same syntax for complex time units as `STARTS' does. You may use `STARTS', `ENDS', both, or neither in an `EVERY' clause. If a repeating event does not terminate within its scheduling interval, the result may be multiple instances of the event executing simultaneously. If this is undesirable, you should institute a mechanism to prevent simultaneous instances. For example, you could use the `GET_LOCK()' function, or row or table locking. The `ON SCHEDULE' clause may use expressions involving built-in MySQL functions and user variables to obtain any of the TIMESTAMP or INTERVAL values which it contains. You may not use stored functions or user-defined functions in such expressions, nor may you use any table references; however, you may use `SELECT FROM DUAL'. This is true for both *Note `CREATE EVENT': create-event. and *Note `ALTER EVENT': alter-event. statements. Beginning with MySQL 5.1.13, references to stored functions, user-defined functions, and tables in such cases are specifically not permitted, and fail with an error (see Bug#22830). Times in the `ON SCHEDULE' clause are interpreted using the current session `time_zone' value. This becomes the event time zone; that is, the time zone that is used for event scheduling and is in effect within the event as it executes. These times are converted to UTC and stored along with the event time zone in the `mysql.event' table. This enables event execution to proceed as defined regardless of any subsequent changes to the server time zone or daylight saving time effects. For additional information about representation of event times, see *Note events-metadata::. See also *Note show-events::, and *Note events-table::. *Note*: Prior to MySQL 5.1.17, the event time zone is not stored. The `mysql.event' table must be updated before events created in earlier releases can be created, altered, viewed, or used in MySQL 5.1.17 or later. You can use *Note `mysql_upgrade': mysql-upgrade. for this (see *Note mysql-upgrade::). Normally, once an event has expired, it is immediately dropped. You can override this behavior by specifying `ON COMPLETION PRESERVE'. Using `ON COMPLETION NOT PRESERVE' merely makes the default nonpersistent behavior explicit. You can create an event but prevent it from being active using the `DISABLE' keyword. Alternatively, you can use `ENABLE' to make explicit the default status, which is active. This is most useful in conjunction with *Note `ALTER EVENT': alter-event. (see *Note alter-event::). Beginning with MySQL 5.1.18, a third value may also appear in place of `ENABLED' or `DISABLED'; `DISABLE ON SLAVE' is set for the status of an event on a replication slave to indicate that the event was created on the master and replicated to the slave, but is not executed on the slave. See *Note replication-features-invoked::. You may supply a comment for an event using a `COMMENT' clause. COMMENT may be any string of up to 64 characters that you wish to use for describing the event. The comment text, being a string literal, must be surrounded by quotation marks. The *Note `DO': do. clause specifies an action carried by the event, and consists of an SQL statement. Nearly any valid MySQL statement that can be used in a stored routine can also be used as the action statement for a scheduled event. (See *Note stored-program-restrictions::.) For example, the following event `e_hourly' deletes all rows from the `sessions' table once per hour, where this table is part of the `site_activity' schema: CREATE EVENT e_hourly ON SCHEDULE EVERY 1 HOUR COMMENT 'Clears out sessions table each hour.' DO DELETE FROM site_activity.sessions; MySQL stores the `sql_mode' system variable setting that is in effect at the time an event is created, and always executes the event with this setting in force, _regardless of the current server SQL mode_. A *Note `CREATE EVENT': create-event. statement that contains an *Note `ALTER EVENT': alter-event. statement in its *Note `DO': do. clause appears to succeed; however, when the server attempts to execute the resulting scheduled event, the execution fails with an error. *Note*: Statements such as *Note `SELECT': select. or *Note `SHOW': show. that merely return a result set have no effect when used in an event; the output from these is not sent to the MySQL Monitor, nor is it stored anywhere. However, you can use statements such as *Note `SELECT ... INTO': select. and *Note `INSERT INTO ... SELECT': insert-select. that store a result. (See the next example in this section for an instance of the latter.) The schema to which an event belongs is the default schema for table references in the *Note `DO': do. clause. Any references to tables in other schemas must be qualified with the proper schema name. (In MySQL 5.1.6, all tables referenced in event *Note `DO': do. clauses had to include a reference to the schema.) As with stored routines, you can use compound-statement syntax in the *Note `DO': do. clause by using the `BEGIN' and `END' keywords, as shown here: delimiter | CREATE EVENT e_daily ON SCHEDULE EVERY 1 DAY COMMENT 'Saves total number of sessions then clears the table each day' DO BEGIN INSERT INTO site_activity.totals (time, total) SELECT CURRENT_TIMESTAMP, COUNT(*) FROM site_activity.sessions; DELETE FROM site_activity.sessions; END | delimiter ; This example uses the `delimiter' command to change the statement delimiter. See *Note stored-programs-defining::. More complex compound statements, such as those used in stored routines, are possible in an event. This example uses local variables, an error handler, and a flow control construct: delimiter | CREATE EVENT e ON SCHEDULE EVERY 5 SECOND DO BEGIN DECLARE v INTEGER; DECLARE CONTINUE HANDLER FOR SQLEXCEPTION BEGIN END; SET v = 0; WHILE v < 5 DO INSERT INTO t1 VALUES (0); UPDATE t2 SET s1 = s1 + 1; SET v = v + 1; END WHILE; END | delimiter ; There is no way to pass parameters directly to or from events; however, it is possible to invoke a stored routine with parameters within an event: CREATE EVENT e_call_myproc ON SCHEDULE AT CURRENT_TIMESTAMP + INTERVAL 1 DAY DO CALL myproc(5, 27); If an event's definer has the `SUPER' privilege, the event can read and write global variables. As granting this privilege entails a potential for abuse, extreme care must be taken in doing so. Generally, any statements that are valid in stored routines may be used for action statements executed by events. For more information about statements permissible within stored routines, see *Note stored-routines-syntax::. You can create an event as part of a stored routine, but an event cannot be created by another event.  File: manual.info, Node: create-function, Next: create-index, Prev: create-event, Up: sql-syntax-data-definition 13.1.12 The `CREATE FUNCTION' Statement --------------------------------------- The *Note `CREATE FUNCTION': create-function. statement is used to create stored functions and user-defined functions (UDFs): * For information about creating stored functions, see *Note create-procedure::. * For information about creating user-defined functions, see *Note create-function-udf::.  File: manual.info, Node: create-index, Next: create-logfile-group, Prev: create-function, Up: sql-syntax-data-definition 13.1.13 `CREATE INDEX' Syntax ----------------------------- CREATE [ONLINE|OFFLINE] [UNIQUE|FULLTEXT|SPATIAL] INDEX INDEX_NAME [INDEX_TYPE] ON TBL_NAME (INDEX_COL_NAME,...) [INDEX_OPTION] ... INDEX_COL_NAME: COL_NAME [(LENGTH)] [ASC | DESC] INDEX_TYPE: USING {BTREE | HASH} INDEX_OPTION: KEY_BLOCK_SIZE [=] VALUE | INDEX_TYPE | WITH PARSER PARSER_NAME *Note `CREATE INDEX': create-index. is mapped to an *Note `ALTER TABLE': alter-table. statement to create indexes. See *Note alter-table::. *Note `CREATE INDEX': create-index. cannot be used to create a `PRIMARY KEY'; use *Note `ALTER TABLE': alter-table. instead. For more information about indexes, see *Note mysql-indexes::. Normally, you create all indexes on a table at the time the table itself is created with *Note `CREATE TABLE': create-table. See *Note create-table::. *Note `CREATE INDEX': create-index. enables you to add indexes to existing tables. A column list of the form `(col1,col2,...)' creates a multiple-column index. Index values are formed by concatenating the values of the given columns. Indexes can be created that use only the leading part of column values, using `COL_NAME(LENGTH)' syntax to specify an index prefix length: * Prefixes can be specified for *Note `CHAR': char, *Note `VARCHAR': char, *Note `BINARY': binary-varbinary, and *Note `VARBINARY': binary-varbinary. columns. * *Note `BLOB': blob. and *Note `TEXT': blob. columns also can be indexed, but a prefix length _must_ be given. * Prefix lengths are given in characters for nonbinary string types and in bytes for binary string types. That is, index entries consist of the first LENGTH characters of each column value for *Note `CHAR': char, *Note `VARCHAR': char, and *Note `TEXT': blob. columns, and the first LENGTH bytes of each column value for *Note `BINARY': binary-varbinary, *Note `VARBINARY': binary-varbinary, and *Note `BLOB': blob. columns. * For spatial columns, prefix values cannot be given, as described later in this section. The statement shown here creates an index using the first 10 characters of the `name' column: CREATE INDEX part_of_name ON customer (name(10)); If names in the column usually differ in the first 10 characters, this index should not be much slower than an index created from the entire `name' column. Also, using column prefixes for indexes can make the index file much smaller, which could save a lot of disk space and might also speed up *Note `INSERT': insert. operations. Prefix support and lengths of prefixes (where supported) are storage engine dependent. For example, a prefix can be up to 1000 bytes long for `MyISAM' tables, and 767 bytes for `InnoDB' tables. The `NDBCLUSTER' storage engine does not support prefixes (see *Note mysql-cluster-limitations-unsupported::). *Note*: Prefix limits are measured in bytes, whereas the prefix length in *Note `CREATE INDEX': create-index. statements is interpreted as number of characters for nonbinary data types (*Note `CHAR': char, *Note `VARCHAR': char, *Note `TEXT': blob.). Take this into account when specifying a prefix length for a column that uses a multi-byte character set. Beginning with MySQL 5.1.17, indexes on variable-width columns of *Note `NDBCLUSTER': mysql-cluster. tables are created without any table copying. The table is not locked against access from other MySQL Cluster API nodes, although it is locked against other operations on the _same_ API node for the duration of the operation. This is done automatically by the server whenever it determines that it is possible to do so; you do not have to use any special SQL syntax or server options to cause it to happen. In standard MySQL 5.1 releases, it is not possible to override the server when it determines that an index is to be created without table copying. In MySQL Cluster, beginning with MySQL Cluster NDB 6.2.5 and MySQL Cluster NDB 6.3.3, you can create indexes offline (which causes the table to be locked to all API nodes in the cluster) using the `OFFLINE' keyword. The rules and limitations governing `CREATE OFFLINE INDEX' and `CREATE ONLINE INDEX' are the same as for `ALTER OFFLINE TABLE ... ADD INDEX' and `ALTER ONLINE TABLE ... ADD INDEX'. You cannot cause the noncopying creation of an index that would normally be created offline by using the `ONLINE' keyword (if it is not possible to perform the *Note `CREATE INDEX': create-index. operation without table copying, the `ONLINE' keyword is ignored). For more information, see *Note alter-table-online-operations::. *Note*: The `ONLINE' and `OFFLINE' keywords are available only in MySQL Cluster NDB 6.2.5, 6.3.3, and later MySQL Cluster releases; attempting to use these keywords in earlier MySQL Cluster releases or standard MySQL 5.1 releases results in a syntax error. A `UNIQUE' index creates a constraint such that all values in the index must be distinct. An error occurs if you try to add a new row with a key value that matches an existing row. For all engines, a `UNIQUE' index permits multiple `NULL' values for columns that can contain `NULL'. If you specify a prefix value for a column in a `UNIQUE' index, the column values must be unique within the prefix. `FULLTEXT' indexes are supported only for `MyISAM' tables and can include only *Note `CHAR': char, *Note `VARCHAR': char, and *Note `TEXT': blob. columns. Indexing always happens over the entire column; column prefix indexing is not supported and any prefix length is ignored if specified. See *Note fulltext-search::, for details of operation. The `MyISAM', `InnoDB', *Note `NDB': mysql-cluster, and `ARCHIVE' storage engines support spatial columns such as (`POINT' and `GEOMETRY'. (*Note spatial-extensions::, describes the spatial data types.) However, support for spatial column indexing varies among engines. Spatial and nonspatial indexes are available according to the following rules. Characteristics of spatial indexes (created using `SPATIAL INDEX'): * Available only for `MyISAM' tables. Specifying `SPATIAL INDEX' for other storage engines results in an error. * Indexed columns must be `NOT NULL'. * In MySQL 5.1, column prefix lengths are prohibited. The full width of each column is indexed. Characteristics of nonspatial indexes (created with `INDEX', `UNIQUE', or `PRIMARY KEY'): * Permitted for any storage engine that supports spatial columns except `ARCHIVE'. * Columns can be `NULL' unless the index is a primary key. * For each spatial column in a non-`SPATIAL' index except `POINT' columns, a column prefix length must be specified. (This is the same requirement as for indexed *Note `BLOB': blob. columns.) The prefix length is given in bytes. * The index type for a non-`SPATIAL' index depends on the storage engine. Currently, B-tree is used. In MySQL 5.1: * You can add an index on a column that can have `NULL' values only if you are using the `MyISAM', `InnoDB', or `MEMORY' storage engine. * You can add an index on a *Note `BLOB': blob. or *Note `TEXT': blob. column only if you are using the `MyISAM', or `InnoDB' storage engine. An INDEX_COL_NAME specification can end with `ASC' or `DESC'. These keywords are permitted for future extensions for specifying ascending or descending index value storage. Currently, they are parsed but ignored; index values are always stored in ascending order. As of MySQL 5.1.10, index options can be given following the index column list. An INDEX_OPTION value can be any of the following: * `KEY_BLOCK_SIZE [=] VALUE' This option provides a hint to the storage engine about the size in bytes to use for index key blocks. The engine is permitted to change the value if necessary. A value of 0 indicates that the default value should be used. * INDEX_TYPE Some storage engines permit you to specify an index type when creating an index. The permissible index type values supported by different storage engines are shown in the following table. Where multiple index types are listed, the first one is the default when no index type specifier is given. Storage Permissible Index Types Engine `MyISAM' `BTREE' `InnoDB' `BTREE' `MEMORY'/`HEAP'`HASH', `BTREE' *Note `NDB': `HASH', `BTREE' (see note in text) mysql-cluster. Example: CREATE TABLE lookup (id INT) ENGINE = MEMORY; CREATE INDEX id_index ON lookup (id) USING BTREE; `BTREE' indexes are implemented by the *Note `NDBCLUSTER': mysql-cluster. storage engine as T-tree indexes. *Note*: For indexes on *Note `NDB': mysql-cluster. table columns, the `USING' option can be specified only for a unique index or primary key. `USING HASH' prevents the creation of an implicit ordered index; otherwise, creating a unique index or primary key on an *Note `NDB': mysql-cluster. table automatically results in the creation of both an ordered index and a hash index, each of which indexes the same set of columns. This means that a query using a unique index or primary key on a `NULL' column is always handled by *Note `NDB': mysql-cluster. with a full scan of the table. In particular, if you plan to use an `IS NULL' or `IS NOT NULL' condition involving a unique index or primary key column of an *Note `NDB': mysql-cluster. table, you should create any such index without `USING HASH'. The INDEX_TYPE clause cannot be used together with `SPATIAL INDEX'. If you specify an index type that is not legal for a given storage engine, but there is another index type available that the engine can use without affecting query results, the engine uses the available type. The parser recognizes `RTREE' as a type name, but currently this cannot be specified for any storage engine. Before MySQL 5.1.10, this option can be given only before the `ON TBL_NAME' clause. Use of the option in this position is deprecated as of 5.1.10 and support for it there will be removed in a future MySQL release. If an INDEX_TYPE option is given in both the earlier and later positions, the final option applies. `TYPE TYPE_NAME' is recognized as a synonym for `USING TYPE_NAME'. However, `USING' is the preferred form. * `WITH PARSER PARSER_NAME' This option can be used only with `FULLTEXT' indexes. It associates a parser plugin with the index if full-text indexing and searching operations need special handling. See *Note plugin-api::, for details on creating plugins.  File: manual.info, Node: create-logfile-group, Next: create-procedure, Prev: create-index, Up: sql-syntax-data-definition 13.1.14 `CREATE LOGFILE GROUP' Syntax ------------------------------------- CREATE LOGFILE GROUP LOGFILE_GROUP ADD UNDOFILE 'UNDO_FILE' [INITIAL_SIZE [=] INITIAL_SIZE] [UNDO_BUFFER_SIZE [=] UNDO_BUFFER_SIZE] [REDO_BUFFER_SIZE [=] REDO_BUFFER_SIZE] [NODEGROUP [=] NODEGROUP_ID] [WAIT] [COMMENT [=] COMMENT_TEXT] ENGINE [=] ENGINE_NAME This statement creates a new log file group named LOGFILE_GROUP having a single `UNDO' file named 'UNDO_FILE'. A *Note `CREATE LOGFILE GROUP': create-logfile-group. statement has one and only one `ADD UNDOFILE' clause. For rules covering the naming of log file groups, see *Note identifiers::. *Note*: All MySQL Cluster Disk Data objects share the same namespace. This means that _each Disk Data object_ must be uniquely named (and not merely each Disk Data object of a given type). For example, you cannot have a tablespace and a log file group with the same name, or a tablespace and a data file with the same name. Beginning with MySQL 5.1.8, you can have only one log file group per Cluster at any given time. (See Bug#16386) Prior to MySQL Cluster NDB 6.2.17, 6.3.23, and 6.4.3, path and file names for undo log files could not be longer than 128 characters. (Bug#31769) The optional `INITIAL_SIZE' parameter sets the `UNDO' file's initial size; if not specified, it defaults to `128M' (128 megabytes). The optional `UNDO_BUFFER_SIZE' parameter sets the size used by the `UNDO' buffer for the log file group; The default value for `UNDO_BUFFER_SIZE' is `8M' (eight megabytes); this value cannot exceed the amount of system memory available. Both of these parameters are specified in bytes. You may optionally follow either or both of these with a one-letter abbreviation for an order of magnitude, similar to those used in `my.cnf'. Generally, this is one of the letters `M' (for megabytes) or `G' (for gigabytes). The memory used for both `INITIAL_SIZE' and `UNDO_BUFFER_SIZE' comes from the global pool whose size is determined by the value of the `SharedGlobalMemory' data node configuration parameter. This includes any default value implied for these options by the setting of the `InitialLogFileGroup' data node configuration parameter. Beginning with MySQL Cluster NDB 6.2.17, 6.3.23, and 6.4.3, the maximum permitted for `UNDO_BUFFER_SIZE' is `600M'; previously, it was `150M'. (Bug#34102) On 32-bit systems, the maximum supported value for `INITIAL_SIZE' is `4G'. (Bug#29186) Beginning with MySQL Cluster NDB 2.1.18, 6.3.24, and 7.0.4, the minimum permitted value for `INITIAL_SIZE' is `1M'. (Bug#29574) The `ENGINE' parameter determines the storage engine to be used by this log file group, with ENGINE_NAME being the name of the storage engine. In MySQL 5.1. ENGINE_NAME must be one of the values *Note `NDB': mysql-cluster. or *Note `NDBCLUSTER': mysql-cluster. REDO_BUFFER_SIZE, `NODEGROUP', `WAIT', and `COMMENT' are parsed but ignored, and so have no effect in MySQL 5.1. These options are intended for future expansion. When used with `ENGINE [=] NDB', a log file group and associated `UNDO' log file are created on each Cluster data node. You can verify that the `UNDO' files were created and obtain information about them by querying the *Note `INFORMATION_SCHEMA.FILES': files-table. table. For example: mysql> SELECT LOGFILE_GROUP_NAME, LOGFILE_GROUP_NUMBER, EXTRA -> FROM INFORMATION_SCHEMA.FILES -> WHERE FILE_NAME = 'undo_10.dat'; +--------------------+----------------------+----------------+ | LOGFILE_GROUP_NAME | LOGFILE_GROUP_NUMBER | EXTRA | +--------------------+----------------------+----------------+ | lg_3 | 11 | CLUSTER_NODE=3 | | lg_3 | 11 | CLUSTER_NODE=4 | +--------------------+----------------------+----------------+ 2 rows in set (0.06 sec) *Note `CREATE LOGFILE GROUP': create-logfile-group. was added in MySQL 5.1.6. In MySQL 5.1, it is useful only with Disk Data storage for MySQL Cluster. See *Note mysql-cluster-disk-data::.  File: manual.info, Node: create-procedure, Next: create-server, Prev: create-logfile-group, Up: sql-syntax-data-definition 13.1.15 `CREATE PROCEDURE' and `CREATE FUNCTION' Syntax ------------------------------------------------------- CREATE [DEFINER = { USER | CURRENT_USER }] PROCEDURE SP_NAME ([PROC_PARAMETER[,...]]) [CHARACTERISTIC ...] ROUTINE_BODY CREATE [DEFINER = { USER | CURRENT_USER }] FUNCTION SP_NAME ([FUNC_PARAMETER[,...]]) RETURNS TYPE [CHARACTERISTIC ...] ROUTINE_BODY PROC_PARAMETER: [ IN | OUT | INOUT ] PARAM_NAME TYPE FUNC_PARAMETER: PARAM_NAME TYPE TYPE: ANY VALID MYSQL DATA TYPE CHARACTERISTIC: COMMENT 'STRING' | LANGUAGE SQL | [NOT] DETERMINISTIC | { CONTAINS SQL | NO SQL | READS SQL DATA | MODIFIES SQL DATA } | SQL SECURITY { DEFINER | INVOKER } ROUTINE_BODY: VALID SQL ROUTINE STATEMENT These statements create stored routines. By default, a routine is associated with the default database. To associate the routine explicitly with a given database, specify the name as DB_NAME.SP_NAME when you create it. The *Note `CREATE FUNCTION': create-function. statement is also used in MySQL to support UDFs (user-defined functions). See *Note adding-functions::. A UDF can be regarded as an external stored function. Stored functions share their namespace with UDFs. See *Note function-resolution::, for the rules describing how the server interprets references to different kinds of functions. To invoke a stored procedure, use the *Note `CALL': call. statement (see *Note call::). To invoke a stored function, refer to it in an expression. The function returns a value during expression evaluation. *Note `CREATE PROCEDURE': create-procedure. and *Note `CREATE FUNCTION': create-function. require the `CREATE ROUTINE' privilege. They might also require the `SUPER' privilege, depending on the `DEFINER' value, as described later in this section. If binary logging is enabled, *Note `CREATE FUNCTION': create-function. might require the `SUPER' privilege, as described in *Note stored-programs-logging::. By default, MySQL automatically grants the `ALTER ROUTINE' and `EXECUTE' privileges to the routine creator. This behavior can be changed by disabling the `automatic_sp_privileges' system variable. See *Note stored-routines-privileges::. The `DEFINER' and `SQL SECURITY' clauses specify the security context to be used when checking access privileges at routine execution time, as described later in this section. If the routine name is the same as the name of a built-in SQL function, a syntax error occurs unless you use a space between the name and the following parenthesis when defining the routine or invoking it later. For this reason, avoid using the names of existing SQL functions for your own stored routines. The `IGNORE_SPACE' SQL mode applies to built-in functions, not to stored routines. It is always permissible to have spaces after a stored routine name, regardless of whether `IGNORE_SPACE' is enabled. The parameter list enclosed within parentheses must always be present. If there are no parameters, an empty parameter list of `()' should be used. Parameter names are not case sensitive. Each parameter is an `IN' parameter by default. To specify otherwise for a parameter, use the keyword `OUT' or `INOUT' before the parameter name. *Note*: Specifying a parameter as `IN', `OUT', or `INOUT' is valid only for a `PROCEDURE'. For a `FUNCTION', parameters are always regarded as `IN' parameters. An `IN' parameter passes a value into a procedure. The procedure might modify the value, but the modification is not visible to the caller when the procedure returns. An `OUT' parameter passes a value from the procedure back to the caller. Its initial value is `NULL' within the procedure, and its value is visible to the caller when the procedure returns. An `INOUT' parameter is initialized by the caller, can be modified by the procedure, and any change made by the procedure is visible to the caller when the procedure returns. For each `OUT' or `INOUT' parameter, pass a user-defined variable in the *Note `CALL': call. statement that invokes the procedure so that you can obtain its value when the procedure returns. If you are calling the procedure from within another stored procedure or function, you can also pass a routine parameter or local routine variable as an `IN' or `INOUT' parameter. The following example shows a simple stored procedure that uses an `OUT' parameter: mysql> delimiter // mysql> CREATE PROCEDURE simpleproc (OUT param1 INT) -> BEGIN -> SELECT COUNT(*) INTO param1 FROM t; -> END// Query OK, 0 rows affected (0.00 sec) mysql> delimiter ; mysql> CALL simpleproc(@a); Query OK, 0 rows affected (0.00 sec) mysql> SELECT @a; +------+ | @a | +------+ | 3 | +------+ 1 row in set (0.00 sec) The example uses the *Note `mysql': mysql. client `delimiter' command to change the statement delimiter from `;' to `//' while the procedure is being defined. This enables the `;' delimiter used in the procedure body to be passed through to the server rather than being interpreted by *Note `mysql': mysql. itself. See *Note stored-programs-defining::. The `RETURNS' clause may be specified only for a `FUNCTION', for which it is mandatory. It indicates the return type of the function, and the function body must contain a `RETURN VALUE' statement. If the *Note `RETURN': return. statement returns a value of a different type, the value is coerced to the proper type. For example, if a function specifies an *Note `ENUM': enum. or *Note `SET': set. value in the `RETURNS' clause, but the *Note `RETURN': return. statement returns an integer, the value returned from the function is the string for the corresponding *Note `ENUM': enum. member of set of *Note `SET': set. members. The following example function takes a parameter, performs an operation using an SQL function, and returns the result. In this case, it is unnecessary to use `delimiter' because the function definition contains no internal `;' statement delimiters: mysql> CREATE FUNCTION hello (s CHAR(20)) mysql> RETURNS CHAR(50) DETERMINISTIC -> RETURN CONCAT('Hello, ',s,'!'); Query OK, 0 rows affected (0.00 sec) mysql> SELECT hello('world'); +----------------+ | hello('world') | +----------------+ | Hello, world! | +----------------+ 1 row in set (0.00 sec) Parameter types and function return types can be declared to use any valid data type, except that the `COLLATE' attribute cannot be used. The ROUTINE_BODY consists of a valid SQL routine statement. This can be a simple statement such as *Note `SELECT': select. or *Note `INSERT': insert, or a compound statement written using `BEGIN' and `END'. Compound statements can contain declarations, loops, and other control structure statements. The syntax for these statements is described in *Note sql-syntax-compound-statements::. MySQL permits routines to contain DDL statements, such as `CREATE' and `DROP'. MySQL also permits stored procedures (but not stored functions) to contain SQL transaction statements such as *Note `COMMIT': commit. Stored functions may not contain statements that perform explicit or implicit commit or rollback. Support for these statements is not required by the SQL standard, which states that each DBMS vendor may decide whether to permit them. Statements that return a result set can be used within a stored procedure but not within a stored function. This prohibition includes *Note `SELECT': select. statements that do not have an `INTO VAR_LIST' clause and other statements such as *Note `SHOW': show, *Note `EXPLAIN': explain, and *Note `CHECK TABLE': check-table. For statements that can be determined at function definition time to return a result set, a `Not allowed to return a result set from a function' error occurs (`ER_SP_NO_RETSET'). For statements that can be determined only at runtime to return a result set, a `PROCEDURE %s can't return a result set in the given context' error occurs (`ER_SP_BADSELECT'). *Note `USE': use. statements within stored routines are not permitted. When a routine is invoked, an implicit `USE DB_NAME' is performed (and undone when the routine terminates). This causes the routine to have the given default database while it executes. References to objects in databases other than the routine default database should be qualified with the appropriate database name. For additional information about statements that are not permitted in stored routines, see *Note stored-program-restrictions::. For information about invoking stored procedures from within programs written in a language that has a MySQL interface, see *Note call::. MySQL stores the `sql_mode' system variable setting that is in effect at the time a routine is created, and always executes the routine with this setting in force, _regardless of the server SQL mode in effect when the routine is invoked_. The switch from the SQL mode of the invoker to that of the routine occurs after evaluation of arguments and assignment of the resulting values to routine parameters. If you define a routine in strict SQL mode but invoke it in nonstrict mode, assignment of arguments to routine parameters does not take place in strict mode. If you require that expressions passed to a routine be assigned in strict SQL mode, you should invoke the routine with strict mode in effect. The `COMMENT' characteristic is a MySQL extension, and may be used to describe the stored routine. This information is displayed by the *Note `SHOW CREATE PROCEDURE': show-create-procedure. and *Note `SHOW CREATE FUNCTION': show-create-function. statements. The `LANGUAGE' characteristic indicates the language in which the routine is written. The server ignores this characteristic; only SQL routines are supported. A routine is considered `deterministic' if it always produces the same result for the same input parameters, and `not deterministic' otherwise. If neither `DETERMINISTIC' nor `NOT DETERMINISTIC' is given in the routine definition, the default is `NOT DETERMINISTIC'. To declare that a function is deterministic, you must specify `DETERMINISTIC' explicitly. Assessment of the nature of a routine is based on the `honesty' of the creator: MySQL does not check that a routine declared `DETERMINISTIC' is free of statements that produce nondeterministic results. However, misdeclaring a routine might affect results or affect performance. Declaring a nondeterministic routine as `DETERMINISTIC' might lead to unexpected results by causing the optimizer to make incorrect execution plan choices. Declaring a deterministic routine as `NONDETERMINISTIC' might diminish performance by causing available optimizations not to be used. Prior to MySQL 5.1.21, the `DETERMINISTIC' characteristic is accepted, but not used by the optimizer. If binary logging is enabled, the `DETERMINISTIC' characteristic affects which routine definitions MySQL accepts. See *Note stored-programs-logging::. A routine that contains the `NOW()' function (or its synonyms) or `RAND()' is nondeterministic, but it might still be replication-safe. For `NOW()', the binary log includes the timestamp and replicates correctly. `RAND()' also replicates correctly as long as it is called only a single time during the execution of a routine. (You can consider the routine execution timestamp and random number seed as implicit inputs that are identical on the master and slave.) Several characteristics provide information about the nature of data use by the routine. In MySQL, these characteristics are advisory only. The server does not use them to constrain what kinds of statements a routine will be permitted to execute. * `CONTAINS SQL' indicates that the routine does not contain statements that read or write data. This is the default if none of these characteristics is given explicitly. Examples of such statements are `SET @x = 1' or `DO RELEASE_LOCK('abc')', which execute but neither read nor write data. * `NO SQL' indicates that the routine contains no SQL statements. * `READS SQL DATA' indicates that the routine contains statements that read data (for example, *Note `SELECT': select.), but not statements that write data. * `MODIFIES SQL DATA' indicates that the routine contains statements that may write data (for example, *Note `INSERT': insert. or *Note `DELETE': delete.). The `SQL SECURITY' characteristic can be `DEFINER' or `INVOKER' to specify the security context; that is, whether the routine executes using the privileges of the account named in the routine `DEFINER' clause or the user who invokes it. This account must have permission to access the database with which the routine is associated. The default value is `DEFINER'. The user who invokes the routine must have the `EXECUTE' privilege for it, as must the `DEFINER' account if the routine executes in definer security context. The `DEFINER' clause specifies the MySQL account to be used when checking access privileges at routine execution time for routines that have the `SQL SECURITY DEFINER' characteristic. The `DEFINER' clause was added in MySQL 5.1.8. If a USER value is given for the `DEFINER' clause, it should be a MySQL account specified as `'USER_NAME'@'HOST_NAME'' (the same format used in the *Note `GRANT': grant. statement), `CURRENT_USER', or `CURRENT_USER()'. The default `DEFINER' value is the user who executes the *Note `CREATE PROCEDURE': create-procedure. or *Note `CREATE FUNCTION': create-function. or statement. This is the same as specifying `DEFINER = CURRENT_USER' explicitly. If you specify the `DEFINER' clause, these rules determine the legal `DEFINER' user values: * If you do not have the `SUPER' privilege, the only legal USER value is your own account, either specified literally or by using `CURRENT_USER'. You cannot set the definer to some other account. * If you have the `SUPER' privilege, you can specify any syntactically legal account name. If the account does not actually exist, a warning is generated. * Although it is possible to create a routine with a nonexistent `DEFINER' account, an error occurs at routine execution time if the `SQL SECURITY' value is `DEFINER' but the definer account does not exist. For more information about stored routine security, see *Note stored-programs-security::. Within a stored routine that is defined with the `SQL SECURITY DEFINER' characteristic, `CURRENT_USER' returns the routine's `DEFINER' value. For information about user auditing within stored routines, see *Note account-activity-auditing::. Consider the following procedure, which displays a count of the number of MySQL accounts listed in the `mysql.user' table: CREATE DEFINER = 'admin'@'localhost' PROCEDURE account_count() BEGIN SELECT 'Number of accounts:', COUNT(*) FROM mysql.user; END; The procedure is assigned a `DEFINER' account of `'admin'@'localhost'' no matter which user defines it. It executes with the privileges of that account no matter which user invokes it (because the default security characteristic is `DEFINER'). The procedure succeeds or fails depending on whether invoker has the `EXECUTE' privilege for it and `'admin'@'localhost'' has the `SELECT' privilege for the `mysql.user' table. Now suppose that the procedure is defined with the `SQL SECURITY INVOKER' characteristic: CREATE DEFINER = 'admin'@'localhost' PROCEDURE account_count() SQL SECURITY INVOKER BEGIN SELECT 'Number of accounts:', COUNT(*) FROM mysql.user; END; The procedure still has a `DEFINER' of `'admin'@'localhost'', but in this case, it executes with the privileges of the invoking user. Thus, the procedure succeeds or fails depending on whether the invoker has the `EXECUTE' privilege for it and the `SELECT' privilege for the `mysql.user' table. The server handles the data type of a routine parameter, local routine variable created with *Note `DECLARE': declare, or function return value as follows: * Assignments are checked for data type mismatches and overflow. Conversion and overflow problems result in warnings, or errors in strict SQL mode. * Only scalar values can be assigned. For example, a statement such as `SET x = (SELECT 1, 2)' is invalid. * For character data types, if there is a `CHARACTER SET' attribute in the declaration, the specified character set and its default collation are used. If there is no such attribute, the database character set in effect at routine creation time and its default collation are used. (The database character set is given by the value of the `character_set_database' system variable.) The `COLLATE' attribute is not supported. (This includes use of `BINARY', which in this context specifies the binary collation of the character set.)  File: manual.info, Node: create-server, Next: create-table, Prev: create-procedure, Up: sql-syntax-data-definition 13.1.16 `CREATE SERVER' Syntax ------------------------------ CREATE SERVER SERVER_NAME FOREIGN DATA WRAPPER WRAPPER_NAME OPTIONS (OPTION [, OPTION] ...) OPTION: { HOST CHARACTER-LITERAL | DATABASE CHARACTER-LITERAL | USER CHARACTER-LITERAL | PASSWORD CHARACTER-LITERAL | SOCKET CHARACTER-LITERAL | OWNER CHARACTER-LITERAL | PORT NUMERIC-LITERAL } This statement creates the definition of a server for use with the `FEDERATED' storage engine. The *Note `CREATE SERVER': create-server. statement creates a new row within the `servers' table within the `mysql' database. This statement requires the `SUPER' privilege. The `SERVER_NAME' should be a unique reference to the server. Server definitions are global within the scope of the server, it is not possible to qualify the server definition to a specific database. `SERVER_NAME' has a maximum length of 64 characters (names longer than 64 characters are silently truncated), and is case insensitive. You may specify the name as a quoted string. The `WRAPPER_NAME' should be `mysql', and may be quoted with single quotation marks. Other values for `WRAPPER_NAME' are not currently supported. For each `OPTION' you must specify either a character literal or numeric literal. Character literals are UTF-8, support a maximum length of 64 characters and default to a blank (empty) string. String literals are silently truncated to 64 characters. Numeric literals must be a number between 0 and 9999, default value is 0. *Note*: Note that the `OWNER' option is currently not applied, and has no effect on the ownership or operation of the server connection that is created. The *Note `CREATE SERVER': create-server. statement creates an entry in the `mysql.servers' table that can later be used with the *Note `CREATE TABLE': create-table. statement when creating a `FEDERATED' table. The options that you specify will be used to populate the columns in the `mysql.servers' table. The table columns are `Server_name', `Host', `Db', `Username', `Password', `Port' and `Socket'. For example: CREATE SERVER s FOREIGN DATA WRAPPER mysql OPTIONS (USER 'Remote', HOST '192.168.1.106', DATABASE 'test'); The data stored in the table can be used when creating a connection to a `FEDERATED' table: CREATE TABLE t (s1 INT) ENGINE=FEDERATED CONNECTION='s'; For more information, see *Note federated-storage-engine::. *Note `CREATE SERVER': create-server. does not cause an automatic commit. *Note `CREATE SERVER': create-server. was added in MySQL 5.1.15.  File: manual.info, Node: create-table, Next: create-tablespace, Prev: create-server, Up: sql-syntax-data-definition 13.1.17 `CREATE TABLE' Syntax ----------------------------- * Menu: * create-table-select:: `CREATE TABLE ... SELECT' Syntax * silent-column-changes:: Silent Column Specification Changes CREATE [TEMPORARY] TABLE [IF NOT EXISTS] TBL_NAME (CREATE_DEFINITION,...) [TABLE_OPTIONS] [PARTITION_OPTIONS] Or: CREATE [TEMPORARY] TABLE [IF NOT EXISTS] TBL_NAME [(CREATE_DEFINITION,...)] [TABLE_OPTIONS] [PARTITION_OPTIONS] SELECT_STATEMENT Or: CREATE [TEMPORARY] TABLE [IF NOT EXISTS] TBL_NAME { LIKE OLD_TBL_NAME | (LIKE OLD_TBL_NAME) } CREATE_DEFINITION: COL_NAME COLUMN_DEFINITION | [CONSTRAINT [SYMBOL]] PRIMARY KEY [INDEX_TYPE] (INDEX_COL_NAME,...) [INDEX_OPTION] ... | {INDEX|KEY} [INDEX_NAME] [INDEX_TYPE] (INDEX_COL_NAME,...) [INDEX_OPTION] ... | [CONSTRAINT [SYMBOL]] UNIQUE [INDEX|KEY] [INDEX_NAME] [INDEX_TYPE] (INDEX_COL_NAME,...) [INDEX_OPTION] ... | {FULLTEXT|SPATIAL} [INDEX|KEY] [INDEX_NAME] (INDEX_COL_NAME,...) [INDEX_OPTION] ... | [CONSTRAINT [SYMBOL]] FOREIGN KEY [INDEX_NAME] (INDEX_COL_NAME,...) REFERENCE_DEFINITION | CHECK (EXPR) COLUMN_DEFINITION: DATA_TYPE [NOT NULL | NULL] [DEFAULT DEFAULT_VALUE] [AUTO_INCREMENT] [UNIQUE [KEY] | [PRIMARY] KEY] [COMMENT 'STRING'] [COLUMN_FORMAT {FIXED|DYNAMIC|DEFAULT}] [STORAGE {DISK|MEMORY|DEFAULT}] [REFERENCE_DEFINITION] DATA_TYPE: BIT[(LENGTH)] | TINYINT[(LENGTH)] [UNSIGNED] [ZEROFILL] | SMALLINT[(LENGTH)] [UNSIGNED] [ZEROFILL] | MEDIUMINT[(LENGTH)] [UNSIGNED] [ZEROFILL] | INT[(LENGTH)] [UNSIGNED] [ZEROFILL] | INTEGER[(LENGTH)] [UNSIGNED] [ZEROFILL] | BIGINT[(LENGTH)] [UNSIGNED] [ZEROFILL] | REAL[(LENGTH,DECIMALS)] [UNSIGNED] [ZEROFILL] | DOUBLE[(LENGTH,DECIMALS)] [UNSIGNED] [ZEROFILL] | FLOAT[(LENGTH,DECIMALS)] [UNSIGNED] [ZEROFILL] | DECIMAL[(LENGTH[,DECIMALS])] [UNSIGNED] [ZEROFILL] | NUMERIC[(LENGTH[,DECIMALS])] [UNSIGNED] [ZEROFILL] | DATE | TIME | TIMESTAMP | DATETIME | YEAR | CHAR[(LENGTH)] [CHARACTER SET CHARSET_NAME] [COLLATE COLLATION_NAME] | VARCHAR(LENGTH) [CHARACTER SET CHARSET_NAME] [COLLATE COLLATION_NAME] | BINARY[(LENGTH)] | VARBINARY(LENGTH) | TINYBLOB | BLOB | MEDIUMBLOB | LONGBLOB | TINYTEXT [BINARY] [CHARACTER SET CHARSET_NAME] [COLLATE COLLATION_NAME] | TEXT [BINARY] [CHARACTER SET CHARSET_NAME] [COLLATE COLLATION_NAME] | MEDIUMTEXT [BINARY] [CHARACTER SET CHARSET_NAME] [COLLATE COLLATION_NAME] | LONGTEXT [BINARY] [CHARACTER SET CHARSET_NAME] [COLLATE COLLATION_NAME] | ENUM(VALUE1,VALUE2,VALUE3,...) [CHARACTER SET CHARSET_NAME] [COLLATE COLLATION_NAME] | SET(VALUE1,VALUE2,VALUE3,...) [CHARACTER SET CHARSET_NAME] [COLLATE COLLATION_NAME] | SPATIAL_TYPE INDEX_COL_NAME: COL_NAME [(LENGTH)] [ASC | DESC] INDEX_TYPE: USING {BTREE | HASH} INDEX_OPTION: KEY_BLOCK_SIZE [=] VALUE | INDEX_TYPE | WITH PARSER PARSER_NAME REFERENCE_DEFINITION: REFERENCES TBL_NAME (INDEX_COL_NAME,...) [MATCH FULL | MATCH PARTIAL | MATCH SIMPLE] [ON DELETE REFERENCE_OPTION] [ON UPDATE REFERENCE_OPTION] REFERENCE_OPTION: RESTRICT | CASCADE | SET NULL | NO ACTION TABLE_OPTIONS: TABLE_OPTION [[,] TABLE_OPTION] ... TABLE_OPTION: ENGINE [=] ENGINE_NAME | AUTO_INCREMENT [=] VALUE | AVG_ROW_LENGTH [=] VALUE | [DEFAULT] CHARACTER SET [=] CHARSET_NAME | CHECKSUM [=] {0 | 1} | [DEFAULT] COLLATE [=] COLLATION_NAME | COMMENT [=] 'STRING' | CONNECTION [=] 'CONNECT_STRING' | DATA DIRECTORY [=] 'ABSOLUTE PATH TO DIRECTORY' | DELAY_KEY_WRITE [=] {0 | 1} | INDEX DIRECTORY [=] 'ABSOLUTE PATH TO DIRECTORY' | INSERT_METHOD [=] { NO | FIRST | LAST } | KEY_BLOCK_SIZE [=] VALUE | MAX_ROWS [=] VALUE | MIN_ROWS [=] VALUE | PACK_KEYS [=] {0 | 1 | DEFAULT} | PASSWORD [=] 'STRING' | ROW_FORMAT [=] {DEFAULT|DYNAMIC|FIXED|COMPRESSED|REDUNDANT|COMPACT} | TABLESPACE TABLESPACE_NAME [STORAGE {DISK|MEMORY|DEFAULT}] | UNION [=] (TBL_NAME[,TBL_NAME]...) PARTITION_OPTIONS: PARTITION BY { [LINEAR] HASH(EXPR) | [LINEAR] KEY(COLUMN_LIST) | RANGE(EXPR) | LIST(EXPR) } [PARTITIONS NUM] [SUBPARTITION BY { [LINEAR] HASH(EXPR) | [LINEAR] KEY(COLUMN_LIST) } [SUBPARTITIONS NUM] ] [(PARTITION_DEFINITION [, PARTITION_DEFINITION] ...)] PARTITION_DEFINITION: PARTITION PARTITION_NAME [VALUES {LESS THAN {(EXPR) | `MAXVALUE'} | IN (VALUE_LIST)}] [[STORAGE] ENGINE [=] ENGINE_NAME] [COMMENT [=] 'COMMENT_TEXT' ] [DATA DIRECTORY [=] '`DATA_DIR''] [INDEX DIRECTORY [=] '`INDEX_DIR''] [MAX_ROWS [=] MAX_NUMBER_OF_ROWS] [MIN_ROWS [=] MIN_NUMBER_OF_ROWS] [TABLESPACE [=] TABLESPACE_NAME] [NODEGROUP [=] NODE_GROUP_ID] [(SUBPARTITION_DEFINITION [, SUBPARTITION_DEFINITION] ...)] SUBPARTITION_DEFINITION: SUBPARTITION LOGICAL_NAME [[STORAGE] ENGINE [=] ENGINE_NAME] [COMMENT [=] 'COMMENT_TEXT' ] [DATA DIRECTORY [=] '`DATA_DIR''] [INDEX DIRECTORY [=] '`INDEX_DIR''] [MAX_ROWS [=] MAX_NUMBER_OF_ROWS] [MIN_ROWS [=] MIN_NUMBER_OF_ROWS] [TABLESPACE [=] TABLESPACE_NAME] [NODEGROUP [=] NODE_GROUP_ID] SELECT_STATEMENT: [IGNORE | REPLACE] [AS] SELECT ... (SOME LEGAL SELECT STATEMENT) *Note `CREATE TABLE': create-table. creates a table with the given name. You must have the `CREATE' privilege for the table. Rules for permissible table names are given in *Note identifiers::. By default, the table is created in the default database. An error occurs if the table exists, if there is no default database, or if the database does not exist. The table name can be specified as DB_NAME.TBL_NAME to create the table in a specific database. This works regardless of whether there is a default database, assuming that the database exists. If you use quoted identifiers, quote the database and table names separately. For example, write ``mydb`.`mytbl`', not ``mydb.mytbl`'. You can use the `TEMPORARY' keyword when creating a table. A `TEMPORARY' table is visible only to the current connection, and is dropped automatically when the connection is closed. This means that two different connections can use the same temporary table name without conflicting with each other or with an existing non-`TEMPORARY' table of the same name. (The existing table is hidden until the temporary table is dropped.) To create temporary tables, you must have the `CREATE TEMPORARY TABLES' privilege. *Note*: *Note `CREATE TABLE': create-table. does not automatically commit the current active transaction if you use the `TEMPORARY' keyword. The keywords `IF NOT EXISTS' prevent an error from occurring if the table exists. However, there is no verification that the existing table has a structure identical to that indicated by the *Note `CREATE TABLE': create-table. statement. MySQL represents each table by an `.frm' table format (definition) file in the database directory. The storage engine for the table might create other files as well. In the case of `MyISAM' tables, the storage engine creates data and index files. Thus, for each `MyISAM' table TBL_NAME, there are three disk files. File Purpose `TBL_NAME.frm' Table format (definition) file `TBL_NAME.MYD' Data file `TBL_NAME.MYI' Index file *Note storage-engines::, describes what files each storage engine creates to represent tables. If a table name contains special characters, the names for the table files contain encoded versions of those characters as described in *Note identifier-mapping::. DATA_TYPE represents the data type in a column definition. SPATIAL_TYPE represents a spatial data type. The data type syntax shown is representative only. For a full description of the syntax available for specifying column data types, as well as information about the properties of each type, see *Note data-types::, and *Note spatial-extensions::. Some attributes do not apply to all data types. `AUTO_INCREMENT' applies only to integer and floating-point types. `DEFAULT' does not apply to the *Note `BLOB': blob. or *Note `TEXT': blob. types. * If neither `NULL' nor `NOT NULL' is specified, the column is treated as though `NULL' had been specified. * An integer or floating-point column can have the additional attribute `AUTO_INCREMENT'. When you insert a value of `NULL' (recommended) or `0' into an indexed `AUTO_INCREMENT' column, the column is set to the next sequence value. Typically this is `VALUE+1', where VALUE is the largest value for the column currently in the table. `AUTO_INCREMENT' sequences begin with `1'. To retrieve an `AUTO_INCREMENT' value after inserting a row, use the `LAST_INSERT_ID()' SQL function or the *Note `mysql_insert_id()': mysql-insert-id. C API function. See *Note information-functions::, and *Note mysql-insert-id::. If the `NO_AUTO_VALUE_ON_ZERO' SQL mode is enabled, you can store `0' in `AUTO_INCREMENT' columns as `0' without generating a new sequence value. See *Note server-sql-mode::. *Note*: There can be only one `AUTO_INCREMENT' column per table, it must be indexed, and it cannot have a `DEFAULT' value. An `AUTO_INCREMENT' column works properly only if it contains only positive values. Inserting a negative number is regarded as inserting a very large positive number. This is done to avoid precision problems when numbers `wrap' over from positive to negative and also to ensure that you do not accidentally get an `AUTO_INCREMENT' column that contains `0'. For `MyISAM' tables, you can specify an `AUTO_INCREMENT' secondary column in a multiple-column key. See *Note example-auto-increment::. To make MySQL compatible with some ODBC applications, you can find the `AUTO_INCREMENT' value for the last inserted row with the following query: SELECT * FROM TBL_NAME WHERE AUTO_COL IS NULL For information about `InnoDB' and `AUTO_INCREMENT', see *Note innodb-auto-increment-handling::. For information about `AUTO_INCREMENT' and MySQL Replication, see *Note replication-features-auto-increment::. * Character data types (*Note `CHAR': char, *Note `VARCHAR': char, *Note `TEXT': blob.) can include `CHARACTER SET' and `COLLATE' attributes to specify the character set and collation for the column. For details, see *Note charset::. `CHARSET' is a synonym for `CHARACTER SET'. Example: CREATE TABLE t (c CHAR(20) CHARACTER SET utf8 COLLATE utf8_bin); MySQL 5.1 interprets length specifications in character column definitions in characters. (Versions before MySQL 4.1 interpreted them in bytes.) Lengths for *Note `BINARY': binary-varbinary. and *Note `VARBINARY': binary-varbinary. are in bytes. * The `DEFAULT' clause specifies a default value for a column. With one exception, the default value must be a constant; it cannot be a function or an expression. This means, for example, that you cannot set the default for a date column to be the value of a function such as `NOW()' or `CURRENT_DATE'. The exception is that you can specify `CURRENT_TIMESTAMP' as the default for a *Note `TIMESTAMP': datetime. column. See *Note timestamp::. If a column definition includes no explicit `DEFAULT' value, MySQL determines the default value as described in *Note data-type-defaults::. *Note `BLOB': blob. and *Note `TEXT': blob. columns cannot be assigned a default value. *Note `CREATE TABLE': create-table. fails if a date-valued default is not correct according to the `NO_ZERO_IN_DATE' SQL mode, even if strict SQL mode is not enabled. For example, `c1 DATE DEFAULT '2010-00-00'' causes *Note `CREATE TABLE': create-table. to fail with `Invalid default value for 'c1''. Native default value handling in MySQL Cluster NDB 7.0.15, MySQL Cluster NDB 7.1.4, and later Starting with MySQL Cluster NDB 7.0.15 and MySQL Cluster NDB 7.1.4, default values for table columns are stored by *Note `NDBCLUSTER': mysql-cluster, rather than by the MySQL server as was previously the case. Because less data must be sent from an SQL node to the data nodes, inserts on tables having column value defaults can be performed more efficiently than before. Tables created using MySQL Cluster releases previous to the introduction of native default value support can still be used in MySQL Cluster NDB 7.0.15 and later, as well as well as MySQL Cluster NDB 7.1.4 and later. However, such tables continue to use defaults supplied by the MySQL server until they are upgraded. This upgrade can be done by means of an offline *Note `ALTER TABLE': alter-table. statement. *Important*: You cannot set or change a table column's default value using a noncopying *Note `ALTER TABLE': alter-table. operation. Tables created in versions of MySQL Cluster that support native default values cannot be used with versions of MySQL Cluster that lack this support. *Note `NDBCLUSTER': mysql-cluster. tables supporting native default values are still subject to the restrictions on default values imposed by the MySQL server. For more information, see *Note data-type-defaults::. * A comment for a column can be specified with the `COMMENT' option, up to 255 characters long. The comment is displayed by the *Note `SHOW CREATE TABLE': show-create-table. and *Note `SHOW FULL COLUMNS': show-columns. statements. * In MySQL Cluster--beginning with MySQL Cluster NDB 6.2.5 and MySQL Cluster NDB 6.3.2--it is also possible to specify a data storage format for individual columns of *Note `NDB': mysql-cluster. tables using `COLUMN_FORMAT'. Permissible column formats are `FIXED', `DYNAMIC', and `DEFAULT'. `FIXED' is used to specify fixed-width storage, `DYNAMIC' permits the column to be variable-width, and `DEFAULT' causes the column to use fixed-width or variable-width storage as determined by the column's data type (possibly overridden by a `ROW_FORMAT' specifier). For *Note `NDB': mysql-cluster. tables, the default value for `COLUMN_FORMAT' is `DEFAULT'. `COLUMN_FORMAT' currently has no effect on columns of tables using storage engines other than *Note `NDB': mysql-cluster. The `COLUMN_FORMAT' keyword is supported only in the build of *Note `mysqld': mysqld. that is supplied with MySQL Cluster; it is not recognized in any other version of MySQL, where attempting to use `COLUMN_FORMAT' causes a syntax error. * For *Note `NDB': mysql-cluster. tables, beginning with MySQL Cluster NDB 6.2.5 and MySQL Cluster NDB 6.3.2, it is also possible to specify whether the column is stored on disk or in memory by using a `STORAGE' clause. `STORAGE DISK' causes the column to be stored on disk, and `STORAGE MEMORY' causes in-memory storage to be used. The *Note `CREATE TABLE': create-table. statement used must still include a `TABLESPACE' clause: mysql> CREATE TABLE t1 ( -> c1 INT STORAGE DISK, -> c2 INT STORAGE MEMORY -> ) ENGINE NDB; `ERROR 1005 (HY000): Can't create table 'c.t1' (errno: 140)' mysql> CREATE TABLE t1 ( -> c1 INT STORAGE DISK, -> c2 INT STORAGE MEMORY -> ) TABLESPACE ts_1 ENGINE NDB; Query OK, 0 rows affected (1.06 sec) For *Note `NDB': mysql-cluster. tables, `STORAGE DEFAULT' is equivalent to `STORAGE MEMORY'. The `STORAGE' clause has no effect on tables using storage engines other than *Note `NDB': mysql-cluster. The `STORAGE' keyword is supported only in the build of *Note `mysqld': mysqld. that is supplied with MySQL Cluster; it is not recognized in any other version of MySQL, where any attempt to use the `STORAGE' keyword causes a syntax error. * `KEY' is normally a synonym for `INDEX'. The key attribute `PRIMARY KEY' can also be specified as just `KEY' when given in a column definition. This was implemented for compatibility with other database systems. * A `UNIQUE' index creates a constraint such that all values in the index must be distinct. An error occurs if you try to add a new row with a key value that matches an existing row. For all engines, a `UNIQUE' index permits multiple `NULL' values for columns that can contain `NULL'. * A `PRIMARY KEY' is a unique index where all key columns must be defined as `NOT NULL'. If they are not explicitly declared as `NOT NULL', MySQL declares them so implicitly (and silently). A table can have only one `PRIMARY KEY'. If you do not have a `PRIMARY KEY' and an application asks for the `PRIMARY KEY' in your tables, MySQL returns the first `UNIQUE' index that has no `NULL' columns as the `PRIMARY KEY'. In `InnoDB' tables, having a long `PRIMARY KEY' wastes a lot of space. (See *Note innodb-table-and-index::.) * In the created table, a `PRIMARY KEY' is placed first, followed by all `UNIQUE' indexes, and then the nonunique indexes. This helps the MySQL optimizer to prioritize which index to use and also more quickly to detect duplicated `UNIQUE' keys. * A `PRIMARY KEY' can be a multiple-column index. However, you cannot create a multiple-column index using the `PRIMARY KEY' key attribute in a column specification. Doing so only marks that single column as primary. You must use a separate `PRIMARY KEY(INDEX_COL_NAME, ...)' clause. * If a `PRIMARY KEY' or `UNIQUE' index consists of only one column that has an integer type, you can also refer to the column as `_rowid' in *Note `SELECT': select. statements. * In MySQL, the name of a `PRIMARY KEY' is `PRIMARY'. For other indexes, if you do not assign a name, the index is assigned the same name as the first indexed column, with an optional suffix (`_2', `_3', `...') to make it unique. You can see index names for a table using `SHOW INDEX FROM TBL_NAME'. See *Note show-index::. * Some storage engines permit you to specify an index type when creating an index. The syntax for the INDEX_TYPE specifier is `USING TYPE_NAME'. Example: CREATE TABLE lookup (id INT, INDEX USING BTREE (id)) ENGINE = MEMORY; Before MySQL 5.1.10, `USING' can be given only before the index column list. As of 5.1.10, the preferred position is after the column list. Support for use of the option before the column list will be removed in a future MySQL release. INDEX_OPTION values specify additional options for an index. `USING' is one such option. For details about permissible INDEX_OPTION values, see *Note create-index::. For more information about indexes, see *Note mysql-indexes::. * In MySQL 5.1, only the `MyISAM', `InnoDB', and `MEMORY' storage engines support indexes on columns that can have `NULL' values. In other cases, you must declare indexed columns as `NOT NULL' or an error results. * For *Note `CHAR': char, *Note `VARCHAR': char, *Note `BINARY': binary-varbinary, and *Note `VARBINARY': binary-varbinary. columns, indexes can be created that use only the leading part of column values, using `COL_NAME(LENGTH)' syntax to specify an index prefix length. *Note `BLOB': blob. and *Note `TEXT': blob. columns also can be indexed, but a prefix length _must_ be given. Prefix lengths are given in characters for nonbinary string types and in bytes for binary string types. That is, index entries consist of the first LENGTH characters of each column value for *Note `CHAR': char, *Note `VARCHAR': char, and *Note `TEXT': blob. columns, and the first LENGTH bytes of each column value for *Note `BINARY': binary-varbinary, *Note `VARBINARY': binary-varbinary, and *Note `BLOB': blob. columns. Indexing only a prefix of column values like this can make the index file much smaller. See *Note column-indexes::. Only the `MyISAM' and `InnoDB' storage engines support indexing on *Note `BLOB': blob. and *Note `TEXT': blob. columns. For example: CREATE TABLE test (blob_col BLOB, INDEX(blob_col(10))); Prefixes can be up to 1000 bytes long (767 bytes for `InnoDB' tables). Note that prefix limits are measured in bytes, whereas the prefix length in *Note `CREATE TABLE': create-table. statements is interpreted as number of characters for nonbinary data types (*Note `CHAR': char, *Note `VARCHAR': char, *Note `TEXT': blob.). Take this into account when specifying a prefix length for a column that uses a multi-byte character set. * An INDEX_COL_NAME specification can end with `ASC' or `DESC'. These keywords are permitted for future extensions for specifying ascending or descending index value storage. Currently, they are parsed but ignored; index values are always stored in ascending order. * When you use `ORDER BY' or `GROUP BY' on a *Note `TEXT': blob. or *Note `BLOB': blob. column in a *Note `SELECT': select, the server sorts values using only the initial number of bytes indicated by the `max_sort_length' system variable. See *Note blob::. * You can create special `FULLTEXT' indexes, which are used for full-text searches. Only the `MyISAM' storage engine supports `FULLTEXT' indexes. They can be created only from *Note `CHAR': char, *Note `VARCHAR': char, and *Note `TEXT': blob. columns. Indexing always happens over the entire column; column prefix indexing is not supported and any prefix length is ignored if specified. See *Note fulltext-search::, for details of operation. A `WITH PARSER' clause can be specified as an INDEX_OPTION value to associate a parser plugin with the index if full-text indexing and searching operations need special handling. This clause is legal only for `FULLTEXT' indexes. See *Note plugin-api::, for details on creating plugins. * You can create `SPATIAL' indexes on spatial data types. Spatial types are supported only for `MyISAM' tables and indexed columns must be declared as `NOT NULL'. See *Note spatial-extensions::. * `InnoDB' tables support checking of foreign key constraints. See *Note innodb-storage-engine::. Note that the `FOREIGN KEY' syntax in `InnoDB' is more restrictive than the syntax presented for the *Note `CREATE TABLE': create-table. statement at the beginning of this section: The columns of the referenced table must always be explicitly named. `InnoDB' supports both `ON DELETE' and `ON UPDATE' actions on foreign keys. For the precise syntax, see *Note innodb-foreign-key-constraints::. For other storage engines, MySQL Server parses and ignores the `FOREIGN KEY' and `REFERENCES' syntax in *Note `CREATE TABLE': create-table. statements. The `CHECK' clause is parsed but ignored by all storage engines. See *Note ansi-diff-foreign-keys::. *Important*: For users familiar with the ANSI/ISO SQL Standard, please note that no storage engine, including `InnoDB', recognizes or enforces the `MATCH' clause used in referential integrity constraint definitions. Use of an explicit `MATCH' clause will not have the specified effect, and also causes `ON DELETE' and `ON UPDATE' clauses to be ignored. For these reasons, specifying `MATCH' should be avoided. The `MATCH' clause in the SQL standard controls how `NULL' values in a composite (multiple-column) foreign key are handled when comparing to a primary key. `InnoDB' essentially implements the semantics defined by `MATCH SIMPLE', which permit a foreign key to be all or partially `NULL'. In that case, the (child table) row containing such a foreign key is permitted to be inserted, and does not match any row in the referenced (parent) table. It is possible to implement other semantics using triggers. Additionally, MySQL and `InnoDB' require that the referenced columns be indexed for performance. However, the system does not enforce a requirement that the referenced columns be `UNIQUE' or be declared `NOT NULL'. The handling of foreign key references to nonunique keys or keys that contain `NULL' values is not well defined for operations such as *Note `UPDATE': update. or `DELETE CASCADE'. You are advised to use foreign keys that reference only `UNIQUE' and `NOT NULL' keys. Furthermore, `InnoDB' does not recognize or support `inline `REFERENCES' specifications' (as defined in the SQL standard) where the references are defined as part of the column specification. `InnoDB' accepts `REFERENCES' clauses only when specified as part of a separate `FOREIGN KEY' specification. For other storage engines, MySQL Server parses and ignores foreign key specifications. *Note*: Partitioned tables do not support foreign keys. See *Note partitioning-limitations::, for more information. * There is a hard limit of 4096 columns per table, but the effective maximum may be less for a given table and depends on the factors discussed in *Note column-count-limit::. The `TABLESPACE' and `STORAGE' table options were both introduced in MySQL 5.1.6. In MySQL 5.1, they are employed only with *Note `NDBCLUSTER': mysql-cluster. tables. The tablespace named TABLESPACE_NAME must already have been created using *Note `CREATE TABLESPACE': create-tablespace. `STORAGE' determines the type of storage used (disk or memory), and can be one of `DISK', `MEMORY', or `DEFAULT'. `TABLESPACE ... STORAGE DISK' assigns a table to a MySQL Cluster Disk Data tablespace. See *Note mysql-cluster-disk-data::, for more information. *Important*: A `STORAGE' clause cannot be used in a *Note `CREATE TABLE': create-table. statement without a `TABLESPACE' clause. The `ENGINE' table option specifies the storage engine for the table. The `ENGINE' table option takes the storage engine names shown in the following table. Storage Engine Description `ARCHIVE' The archiving storage engine. See *Note archive-storage-engine::. `CSV' Tables that store rows in comma-separated values format. See *Note csv-storage-engine::. `EXAMPLE' An example engine. See *Note example-storage-engine::. `FEDERATED' Storage engine that accesses remote tables. See *Note federated-storage-engine::. `HEAP' This is a synonym for `MEMORY'. `ISAM' Not available in MySQL 5.1. If you are upgrading (_OBSOLETE_) to MySQL 5.1 from a previous version, you should convert any existing `ISAM' tables to `MyISAM' _before_ performing the upgrade. `InnoDB' Transaction-safe tables with row locking and foreign keys. See *Note innodb-storage-engine::. `MEMORY' The data for this storage engine is stored only in memory. See *Note memory-storage-engine::. `MERGE' A collection of `MyISAM' tables used as one table. Also known as `MRG_MyISAM'. See *Note merge-storage-engine::. `MyISAM' The binary portable storage engine that is the default storage engine used by MySQL. See *Note myisam-storage-engine::. *Note Clustered, fault-tolerant, memory-based tables. `NDBCLUSTER': Also known as *Note `NDB': mysql-cluster. See mysql-cluster. *Note mysql-cluster::. If a storage engine is specified that is not available, MySQL uses the default engine instead. Normally, this is `MyISAM'. For example, if a table definition includes the `ENGINE=INNODB' option but the MySQL server does not support `INNODB' tables, the table is created as a `MyISAM' table. This makes it possible to have a replication setup where you have transactional tables on the master but tables created on the slave are nontransactional (to get more speed). In MySQL 5.1, a warning occurs if the storage engine specification is not honored. Engine substitution can be controlled by the setting of the `NO_ENGINE_SUBSTITUTION' SQL mode, as described in *Note server-sql-mode::. *Note*: The older `TYPE' option was synonymous with `ENGINE'. `TYPE' has been deprecated since MySQL 4.0 but is still supported for backward compatibility in MySQL 5.1 (excepting MySQL 5.1.7). Since MySQL 5.1.8, it produces a warning. It is removed in MySQL 5.5. _You should not use `TYPE' in any new applications, and you should immediately begin conversion of existing applications to use `ENGINE' instead_. (See *Note news-5-1-8::.) The other table options are used to optimize the behavior of the table. In most cases, you do not have to specify any of them. These options apply to all storage engines unless otherwise indicated. Options that do not apply to a given storage engine may be accepted and remembered as part of the table definition. Such options then apply if you later use *Note `ALTER TABLE': alter-table. to convert the table to use a different storage engine. * `AUTO_INCREMENT' The initial `AUTO_INCREMENT' value for the table. In MySQL 5.1, this works for `MyISAM', `MEMORY', and `InnoDB' tables. It also works for `ARCHIVE' tables as of MySQL 5.1.6. To set the first auto-increment value for engines that do not support the `AUTO_INCREMENT' table option, insert a `dummy' row with a value one less than the desired value after creating the table, and then delete the dummy row. For engines that support the `AUTO_INCREMENT' table option in *Note `CREATE TABLE': create-table. statements, you can also use `ALTER TABLE TBL_NAME AUTO_INCREMENT = N' to reset the `AUTO_INCREMENT' value. The value cannot be set lower than the maximum value currently in the column. * `AVG_ROW_LENGTH' An approximation of the average row length for your table. You need to set this only for large tables with variable-size rows. When you create a `MyISAM' table, MySQL uses the product of the `MAX_ROWS' and `AVG_ROW_LENGTH' options to decide how big the resulting table is. If you don't specify either option, the maximum size for `MyISAM' data and index files is 256TB by default. (If your operating system does not support files that large, table sizes are constrained by the file size limit.) If you want to keep down the pointer sizes to make the index smaller and faster and you don't really need big files, you can decrease the default pointer size by setting the `myisam_data_pointer_size' system variable. (See *Note server-system-variables::.) If you want all your tables to be able to grow above the default limit and are willing to have your tables slightly slower and larger than necessary, you can increase the default pointer size by setting this variable. Setting the value to 7 permits table sizes up to 65,536TB. * `[DEFAULT] CHARACTER SET' Specify a default character set for the table. `CHARSET' is a synonym for `CHARACTER SET'. If the character set name is `DEFAULT', the database character set is used. * `CHECKSUM' Set this to 1 if you want MySQL to maintain a live checksum for all rows (that is, a checksum that MySQL updates automatically as the table changes). This makes the table a little slower to update, but also makes it easier to find corrupted tables. The *Note `CHECKSUM TABLE': checksum-table. statement reports the checksum. (`MyISAM' only.) * `[DEFAULT] COLLATE' Specify a default collation for the table. * `COMMENT' A comment for the table, up to 60 characters long. * `CONNECTION' The connection string for a `FEDERATED' table. *Note*: Older versions of MySQL used a `COMMENT' option for the connection string. * `DATA DIRECTORY', `INDEX DIRECTORY' By using `DATA DIRECTORY='DIRECTORY'' or `INDEX DIRECTORY='DIRECTORY'' you can specify where the `MyISAM' storage engine should put a table's data file and index file. The directory must be the full path name to the directory, not a relative path. *Important*: Beginning with MySQL 5.1.23, table-level `DATA DIRECTORY' and `INDEX DIRECTORY' options are ignored for partitioned tables. (Bug#32091) These options work only when you are not using the `--skip-symbolic-links' option. Your operating system must also have a working, thread-safe `realpath()' call. See *Note symbolic-links-to-tables::, for more complete information. If a `MyISAM' table is created with no `DATA DIRECTORY' option, the `.MYD' file is created in the database directory. By default, if `MyISAM' finds an existing `.MYD' file in this case, it overwrites it. The same applies to `.MYI' files for tables created with no `INDEX DIRECTORY' option. As of MySQL 5.1.23, to suppress this behavior, start the server with the `--keep_files_on_create' option, in which case `MyISAM' will not overwrite existing files and returns an error instead. If a `MyISAM' table is created with a `DATA DIRECTORY' or `INDEX DIRECTORY' option and an existing `.MYD' or `.MYI' file is found, MyISAM always returns an error. It will not overwrite a file in the specified directory. *Important*: Beginning with MySQL 5.1.24, you cannot use path names that contain the MySQL data directory with `DATA DIRECTORY' or `INDEX DIRECTORY'. This includes partitioned tables and individual table partitions. (See Bug#32167.) * `DELAY_KEY_WRITE' Set this to 1 if you want to delay key updates for the table until the table is closed. See the description of the `delay_key_write' system variable in *Note server-system-variables::. (`MyISAM' only.) * `INSERT_METHOD' If you want to insert data into a `MERGE' table, you must specify with `INSERT_METHOD' the table into which the row should be inserted. `INSERT_METHOD' is an option useful for `MERGE' tables only. Use a value of `FIRST' or `LAST' to have inserts go to the first or last table, or a value of `NO' to prevent inserts. See *Note merge-storage-engine::. * `KEY_BLOCK_SIZE' This option provides a hint to the storage engine about the size in bytes to use for index key blocks. The engine is permitted to change the value if necessary. A value of 0 indicates that the default value should be used. Individual index definitions can specify a `KEY_BLOCK_SIZE' value of their own to override the table value. `KEY_BLOCK_SIZE' was added in MySQL 5.1.10. * `MAX_ROWS' The maximum number of rows you plan to store in the table. This is not a hard limit, but rather a hint to the storage engine that the table must be able to store at least this many rows. The *Note `NDB': mysql-cluster. storage engine treats this value as a maxmimum. If you plan to create very large MySQL Cluster tables (containing millions of rows), you should use this option to insure that *Note `NDB': mysql-cluster. allocates sufficient number of index slots in the hash table used for storing hashes of the table's primary keys by setting `MAX_ROWS = 2 * ROWS', where ROWS is the number of rows that you expect to insert into the table. *Note*: This option was incorrectly ignored by MySQL Cluster NDB 7.0 prior to version 7.0.20 and MySQL Cluster NDB 7.1 prior to version 7.1.9 (see Bug#57360). The maximum `MAX_ROWS' value is 4294967295; larger values are truncated to this limit. * `MIN_ROWS' The minimum number of rows you plan to store in the table. The *Note `MEMORY': memory-storage-engine. storage engine uses this option as a hint about memory use. * `PACK_KEYS' `PACK_KEYS' takes effect only with `MyISAM' tables. Set this option to 1 if you want to have smaller indexes. This usually makes updates slower and reads faster. Setting the option to 0 disables all packing of keys. Setting it to `DEFAULT' tells the storage engine to pack only long *Note `CHAR': char, *Note `VARCHAR': char, *Note `BINARY': binary-varbinary, or *Note `VARBINARY': binary-varbinary. columns. If you do not use `PACK_KEYS', the default is to pack strings, but not numbers. If you use `PACK_KEYS=1', numbers are packed as well. When packing binary number keys, MySQL uses prefix compression: * Every key needs one extra byte to indicate how many bytes of the previous key are the same for the next key. * The pointer to the row is stored in high-byte-first order directly after the key, to improve compression. This means that if you have many equal keys on two consecutive rows, all following `same' keys usually only take two bytes (including the pointer to the row). Compare this to the ordinary case where the following keys takes `storage_size_for_key + pointer_size' (where the pointer size is usually 4). Conversely, you get a significant benefit from prefix compression only if you have many numbers that are the same. If all keys are totally different, you use one byte more per key, if the key is not a key that can have `NULL' values. (In this case, the packed key length is stored in the same byte that is used to mark if a key is `NULL'.) * `PASSWORD' This option is unused. If you have a need to scramble your `.frm' files and make them unusable to any other MySQL server, please contact our sales department. * `RAID_TYPE' `RAID' support has been removed as of MySQL 5.0. * `ROW_FORMAT' Defines how the rows should be stored. For `MyISAM' tables, the option value can be `FIXED' or `DYNAMIC' for static or variable-length row format. *Note `myisampack': myisampack. sets the type to `COMPRESSED'. See *Note myisam-table-formats::. For `InnoDB' tables, rows are stored in compact format (`ROW_FORMAT=COMPACT') by default. The noncompact format used in older versions of MySQL can still be requested by specifying `ROW_FORMAT=REDUNDANT'. *Note*: When executing a *Note `CREATE TABLE': create-table. statement, if you specify a row format which is not supported by the storage engine that is used for the table, the table is created using that storage engine's default row format. The information reported in this column in response to *Note `SHOW TABLE STATUS': show-table-status. is the actual row format used. This may differ from the value in the `Create_options' column because the original *Note `CREATE TABLE': create-table. definition is retained during creation. * *Note `UNION': union. *Note `UNION': union. is used when you want to access a collection of identical `MyISAM' tables as one. This works only with `MERGE' tables. See *Note merge-storage-engine::. You must have `SELECT', `UPDATE', and `DELETE' privileges for the tables you map to a `MERGE' table. *Note*: Formerly, all tables used had to be in the same database as the `MERGE' table itself. This restriction no longer applies. PARTITION_OPTIONS can be used to control partitioning of the table created with *Note `CREATE TABLE': create-table. *Important*: Not all options shown in the syntax for PARTITION_OPTIONS at the beginning of this section are available for all partitioning types. Please see the listings for the following individual types for information specific to each type, and see *Note partitioning::, for more complete information about the workings of and uses for partitioning in MySQL, as well as additional examples of table creation and other statements relating to MySQL partitioning. If used, a PARTITION_OPTIONS clause begins with `PARTITION BY'. This clause contains the function that is used to determine the partition; the function returns an integer value ranging from 1 to NUM, where NUM is the number of partitions. (The maximum number of user-defined partitions which a table may contain is 1024; the number of subpartitions--discussed later in this section--is included in this maximum.) The choices that are available for this function in MySQL 5.1 are shown in the following list: * `HASH(EXPR)': Hashes one or more columns to create a key for placing and locating rows. EXPR is an expression using one or more table columns. This can be any legal MySQL expression (including MySQL functions) that yields a single integer value. For example, these are both valid *Note `CREATE TABLE': create-table. statements using `PARTITION BY HASH': CREATE TABLE t1 (col1 INT, col2 CHAR(5)) PARTITION BY HASH(col1); CREATE TABLE t1 (col1 INT, col2 CHAR(5), col3 DATETIME) PARTITION BY HASH ( YEAR(col3) ); You may not use either `VALUES LESS THAN' or `VALUES IN' clauses with `PARTITION BY HASH'. `PARTITION BY HASH' uses the remainder of EXPR divided by the number of partitions (that is, the modulus). For examples and additional information, see *Note partitioning-hash::. The `LINEAR' keyword entails a somewhat different algorithm. In this case, the number of the partition in which a row is stored is calculated as the result of one or more logical `AND' operations. For discussion and examples of linear hashing, see *Note partitioning-linear-hash::. * `KEY(COLUMN_LIST)': This is similar to `HASH', except that MySQL supplies the hashing function so as to guarantee an even data distribution. The COLUMN_LIST argument is simply a list of table columns. This example shows a simple table partitioned by key, with 4 partitions: CREATE TABLE tk (col1 INT, col2 CHAR(5), col3 DATE) PARTITION BY KEY(col3) PARTITIONS 4; For tables that are partitioned by key, you can employ linear partitioning by using the `LINEAR' keyword. This has the same effect as with tables that are partitioned by `HASH'. That is, the partition number is found using the `&' operator rather than the modulus (see *Note partitioning-linear-hash::, and *Note partitioning-key::, for details). This example uses linear partitioning by key to distribute data between 5 partitions: CREATE TABLE tk (col1 INT, col2 CHAR(5), col3 DATE) PARTITION BY LINEAR KEY(col3) PARTITIONS 5; You may not use either `VALUES LESS THAN' or `VALUES IN' clauses with `PARTITION BY KEY'. * `RANGE': In this case, EXPR shows a range of values using a set of `VALUES LESS THAN' operators. When using range partitioning, you must define at least one partition using `VALUES LESS THAN'. You cannot use `VALUES IN' with range partitioning. `VALUES LESS THAN' can be used with either a literal value or an expression that evaluates to a single value. Suppose that you have a table that you wish to partition on a column containing year values, according to the following scheme. Partition Number: Years Range: 0 1990 and earlier 1 1991 to 1994 2 1995 to 1998 3 1999 to 2002 4 2003 to 2005 5 2006 and later A table implementing such a partitioning scheme can be realized by the *Note `CREATE TABLE': create-table. statement shown here: CREATE TABLE t1 ( year_col INT, some_data INT ) PARTITION BY RANGE (year_col) ( PARTITION p0 VALUES LESS THAN (1991), PARTITION p1 VALUES LESS THAN (1995), PARTITION p2 VALUES LESS THAN (1999), PARTITION p3 VALUES LESS THAN (2002), PARTITION p4 VALUES LESS THAN (2006), PARTITION p5 VALUES LESS THAN MAXVALUE ); `PARTITION ... VALUES LESS THAN ...' statements work in a consecutive fashion. `VALUES LESS THAN MAXVALUE' works to specify `leftover' values that are greater than the maximum value otherwise specified. Note that `VALUES LESS THAN' clauses work sequentially in a manner similar to that of the `case' portions of a `switch ... case' block (as found in many programming languages such as C, Java, and PHP). That is, the clauses must be arranged in such a way that the upper limit specified in each successive `VALUES LESS THAN' is greater than that of the previous one, with the one referencing `MAXVALUE' coming last of all in the list. * `LIST(EXPR)': This is useful when assigning partitions based on a table column with a restricted set of possible values, such as a state or country code. In such a case, all rows pertaining to a certain state or country can be assigned to a single partition, or a partition can be reserved for a certain set of states or countries. It is similar to `RANGE', except that only `VALUES IN' may be used to specify permissible values for each partition. `VALUES IN' is used with a list of values to be matched. For instance, you could create a partitioning scheme such as the following: CREATE TABLE client_firms ( id INT, name VARCHAR(35) ) PARTITION BY LIST (id) ( PARTITION r0 VALUES IN (1, 5, 9, 13, 17, 21), PARTITION r1 VALUES IN (2, 6, 10, 14, 18, 22), PARTITION r2 VALUES IN (3, 7, 11, 15, 19, 23), PARTITION r3 VALUES IN (4, 8, 12, 16, 20, 24) ); When using list partitioning, you must define at least one partition using `VALUES IN'. You cannot use `VALUES LESS THAN' with `PARTITION BY LIST'. *Note*: Currently, the value list used with `VALUES IN' must consist of integer values only. * The number of partitions may optionally be specified with a `PARTITIONS NUM' clause, where NUM is the number of partitions. If both this clause _and_ any `PARTITION' clauses are used, NUM must be equal to the total number of any partitions that are declared using `PARTITION' clauses. *Note*: Whether or not you use a `PARTITIONS' clause in creating a table that is partitioned by `RANGE' or `LIST', you must still include at least one `PARTITION VALUES' clause in the table definition (see below). * A partition may optionally be divided into a number of subpartitions. This can be indicated by using the optional `SUBPARTITION BY' clause. Subpartitioning may be done by `HASH' or `KEY'. Either of these may be `LINEAR'. These work in the same way as previously described for the equivalent partitioning types. (It is not possible to subpartition by `LIST' or `RANGE'.) The number of subpartitions can be indicated using the `SUBPARTITIONS' keyword followed by an integer value. * MySQL 5.1.12 introduces rigorous checking of the value used in a `PARTITIONS' or `SUBPARTITIONS' clause. Beginning with this version, this value must adhere to the following rules: * The value must be a positive, nonzero integer. * No leading zeros are permitted. * The value must be an integer literal, and cannot not be an expression. For example, `PARTITIONS 0.2E+01' is not permitted, even though `0.2E+01' evaluates to `2'. (Bug#15890) *Note*: The expression (EXPR) used in a `PARTITION BY' clause cannot refer to any columns not in the table being created; beginning with MySQL 5.1.23, such references are specifically not permitted and cause the statement to fail with an error. (Bug#29444) Each partition may be individually defined using a PARTITION_DEFINITION clause. The individual parts making up this clause are as follows: * `PARTITION PARTITION_NAME': This specifies a logical name for the partition. * A `VALUES' clause: For range partitioning, each partition must include a `VALUES LESS THAN' clause; for list partitioning, you must specify a `VALUES IN' clause for each partition. This is used to determine which rows are to be stored in this partition. See the discussions of partitioning types in *Note partitioning::, for syntax examples. * An optional `COMMENT' clause may be used to specify a string that describes the partition. Example: COMMENT = 'Data for the years previous to 1999' * `DATA DIRECTORY' and `INDEX DIRECTORY' may be used to indicate the directory where, respectively, the data and indexes for this partition are to be stored. Both the `DATA_DIR' and the `INDEX_DIR' must be absolute system path names. Example: CREATE TABLE th (id INT, name VARCHAR(30), adate DATE) PARTITION BY LIST(YEAR(adate)) ( PARTITION p1999 VALUES IN (1995, 1999, 2003) DATA DIRECTORY = '`/var/appdata/95/data'' INDEX DIRECTORY = '`/var/appdata/95/idx'', PARTITION p2000 VALUES IN (1996, 2000, 2004) DATA DIRECTORY = '`/var/appdata/96/data'' INDEX DIRECTORY = '`/var/appdata/96/idx'', PARTITION p2001 VALUES IN (1997, 2001, 2005) DATA DIRECTORY = '`/var/appdata/97/data'' INDEX DIRECTORY = '`/var/appdata/97/idx'', PARTITION p2000 VALUES IN (1998, 2002, 2006) DATA DIRECTORY = '`/var/appdata/98/data'' INDEX DIRECTORY = '`/var/appdata/98/idx'' ); `DATA DIRECTORY' and `INDEX DIRECTORY' behave in the same way as in the *Note `CREATE TABLE': create-table. statement's TABLE_OPTION clause as used for `MyISAM' tables. One data directory and one index directory may be specified per partition. If left unspecified, the data and indexes are stored by default in the table's database directory. On Windows, the `DATA DIRECTORY' and `INDEX DIRECTORY' options are not supported for individual partitions or subpartitions. Beginning with MySQL 5.1.24, these options are ignored on Windows, except that a warning is generated. (Bug#30459) *Note*: Prior to MySQL 5.1.18, `DATA DIRECTORY' and `INDEX DIRECTORY' were permitted even if the `NO_DIR_IN_CREATE' server SQL mode was in effect at the time that a partitioned table was created. Beginning with MySQL 5.1.18, these options are ignored for creating partitioned tables if `NO_DIR_IN_CREATE' is in effect. (Bug#24633) * `MAX_ROWS' and `MIN_ROWS' may be used to specify, respectively, the maximum and minimum number of rows to be stored in the partition. The values for MAX_NUMBER_OF_ROWS and MIN_NUMBER_OF_ROWS must be positive integers. As with the table-level options with the same names, these act only as `suggestions' to the server and are not hard limits. * The optional `TABLESPACE' clause may be used to designate a tablespace for the partition. Used for MySQL Cluster only. * The partitioning handler accepts a `[STORAGE] ENGINE' option for both `PARTITION' and `SUBPARTITION'. Currently, the only way in which this can be used is to set all partitions or all subpartitions to the same storage engine, and an attempt to set different storage engines for partitions or subpartitions in the same table will give rise to the error `ERROR 1469 (HY000): The mix of handlers in the partitions is not permitted in this version of MySQL'. We expect to lift this restriction on partitioning in a future MySQL release. * The `NODEGROUP' option can be used to make this partition act as part of the node group identified by NODE_GROUP_ID. This option is applicable only to MySQL Cluster. * The partition definition may optionally contain one or more SUBPARTITION_DEFINITION clauses. Each of these consists at a minimum of the `SUBPARTITION NAME', where NAME is an identifier for the subpartition. Except for the replacement of the `PARTITION' keyword with `SUBPARTITION', the syntax for a subpartition definition is identical to that for a partition definition. Subpartitioning must be done by `HASH' or `KEY', and can be done only on `RANGE' or `LIST' partitions. See *Note partitioning-subpartitions::. Partitions can be modified, merged, added to tables, and dropped from tables. For basic information about the MySQL statements to accomplish these tasks, see *Note alter-table::. For more detailed descriptions and examples, see *Note partitioning-management::. *Important*: The original *Note `CREATE TABLE': create-table. statement, including all specifications and table options are stored by MySQL when the table is created. The information is retained so that if you change storage engines, collations or other settings using an *Note `ALTER TABLE': alter-table. statement, the original table options specified are retained. This enables you to change between `InnoDB' and `MyISAM' table types even though the row formats supported by the two engines are different. Because the text of the original statement is retained, but due to the way that certain values and options may be silently reconfigured (such as the `ROW_FORMAT'), the active table definition (accessible through *Note `DESCRIBE': describe. or with *Note `SHOW TABLE STATUS': show-table-status.) and the table creation string (accessible through *Note `SHOW CREATE TABLE': show-create-table.) will report different values. You can create one table from another by adding a *Note `SELECT': select. statement at the end of the *Note `CREATE TABLE': create-table. statement: CREATE TABLE NEW_TBL SELECT * FROM ORIG_TBL; For more information, see *Note create-table-select::. Use `LIKE' to create an empty table based on the definition of another table, including any column attributes and indexes defined in the original table: CREATE TABLE NEW_TBL LIKE ORIG_TBL; The copy is created using the same version of the table storage format as the original table. The `SELECT' privilege is required on the original table. `LIKE' works only for base tables, not for views. `CREATE TABLE ... LIKE' does not preserve any `DATA DIRECTORY' or `INDEX DIRECTORY' table options that were specified for the original table, or any foreign key definitions. If the original table is a `TEMPORARY' table, `CREATE TABLE ... LIKE' does not preserve `TEMPORARY'. To create a `TEMPORARY' destination table, use `CREATE TEMPORARY TABLE ... LIKE'. In MySQL 5.1, changes to the SQL mode do not affect *Note `CREATE TABLE ... LIKE': create-table. If the current SQL mode is different from the mode in effect when the original table was created, the statement succeeds even if the table definition is invalid for the new mode.  File: manual.info, Node: create-table-select, Next: silent-column-changes, Prev: create-table, Up: create-table 13.1.17.1 `CREATE TABLE ... SELECT' Syntax .......................................... You can create one table from another by adding a *Note `SELECT': select. statement at the end of the *Note `CREATE TABLE': create-table. statement: CREATE TABLE NEW_TBL SELECT * FROM ORIG_TBL; MySQL creates new columns for all elements in the *Note `SELECT': select. For example: mysql> CREATE TABLE test (a INT NOT NULL AUTO_INCREMENT, -> PRIMARY KEY (a), KEY(b)) -> ENGINE=MyISAM SELECT b,c FROM test2; This creates a `MyISAM' table with three columns, `a', `b', and `c'. Notice that the columns from the *Note `SELECT': select. statement are appended to the right side of the table, not overlapped onto it. Take the following example: mysql> SELECT * FROM foo; +---+ | n | +---+ | 1 | +---+ mysql> CREATE TABLE bar (m INT) SELECT n FROM foo; Query OK, 1 row affected (0.02 sec) Records: 1 Duplicates: 0 Warnings: 0 mysql> SELECT * FROM bar; +------+---+ | m | n | +------+---+ | NULL | 1 | +------+---+ 1 row in set (0.00 sec) For each row in table `foo', a row is inserted in `bar' with the values from `foo' and default values for the new columns. In a table resulting from *Note `CREATE TABLE ... SELECT': create-table, columns named only in the *Note `CREATE TABLE': create-table. part come first. Columns named in both parts or only in the *Note `SELECT': select. part come after that. The data type of *Note `SELECT': select. columns can be overridden by also specifying the column in the *Note `CREATE TABLE': create-table. part. If any errors occur while copying the data to the table, it is automatically dropped and not created. You can precede the *Note `SELECT': select. by `IGNORE' or *Note `REPLACE': replace. to indicate how to handle rows that duplicate unique key values. With `IGNORE', new rows that duplicate an existing row on a unique key value are discarded. With *Note `REPLACE': replace, new rows replace rows that have the same unique key value. If neither `IGNORE' nor *Note `REPLACE': replace. is specified, duplicate unique key values result in an error. *Note `CREATE TABLE ... SELECT': create-table. does not automatically create any indexes for you. This is done intentionally to make the statement as flexible as possible. If you want to have indexes in the created table, you should specify these before the *Note `SELECT': select. statement: mysql> CREATE TABLE bar (UNIQUE (n)) SELECT n FROM foo; Some conversion of data types might occur. For example, the `AUTO_INCREMENT' attribute is not preserved, and *Note `VARCHAR': char. columns can become *Note `CHAR': char. columns. Retrained attributes are `NULL' (or `NOT NULL') and, for those columns that have them, `CHARACTER SET', `COLLATION', `COMMENT', and the `DEFAULT' clause. When creating a table with *Note `CREATE TABLE ... SELECT': create-table-select, make sure to alias any function calls or expressions in the query. If you do not, the `CREATE' statement might fail or result in undesirable column names. CREATE TABLE artists_and_works SELECT artist.name, COUNT(work.artist_id) AS number_of_works FROM artist LEFT JOIN work ON artist.id = work.artist_id GROUP BY artist.id; You can also explicitly specify the data type for a generated column: CREATE TABLE foo (a TINYINT NOT NULL) SELECT b+1 AS a FROM bar; For *Note `CREATE TABLE ... SELECT': create-table, if `IF NOT EXISTS' is given and the destination table already exists, the result is version dependent. Before MySQL 5.5.6, MySQL handles the statement as follows: * The table definition given in the *Note `CREATE TABLE': create-table. part is ignored. No error occurs, even if the definition does not match that of the existing table. MySQL attempts to insert the rows from the *Note `SELECT': select. part anyway. * If there is a mismatch between the number of columns in the table and the number of columns produced by the *Note `SELECT': select. part, the selected values are assigned to the rightmost columns. For example, if the table contains N columns and the *Note `SELECT': select. produces M columns, where M < N, the selected values are assigned to the M rightmost columns in the table. Each of the initial N - M columns is assigned its default value, either that specified explicitly in the column definition or the implicit column data type default if the definition contains no default. If the *Note `SELECT': select. part produces too many columns (M > N), an error occurs. * If strict SQL mode is enabled and any of these initial columns do not have an explicit default value, the statement fails with an error. The following example illustrates `IF NOT EXISTS' handling: mysql> CREATE TABLE t1 (i1 INT DEFAULT 0, i2 INT, i3 INT, i4 INT); Query OK, 0 rows affected (0.05 sec) mysql> CREATE TABLE IF NOT EXISTS t1 (c1 CHAR(10)) SELECT 1, 2; Query OK, 1 row affected, 1 warning (0.01 sec) Records: 1 Duplicates: 0 Warnings: 0 mysql> SELECT * FROM t1; +------+------+------+------+ | i1 | i2 | i3 | i4 | +------+------+------+------+ | 0 | NULL | 1 | 2 | +------+------+------+------+ 1 row in set (0.00 sec) As of MySQL 5.5.6, handling of *Note `CREATE TABLE IF NOT EXISTS ... SELECT': create-table-select. statements was changed for the case that the destination table already exists. This change also involves a change in MySQL 5.1 beginning with 5.1.51. * Previously, for *Note `CREATE TABLE IF NOT EXISTS ... SELECT': create-table-select, MySQL produced a warning that the table exists, but inserted the rows and wrote the statement to the binary log anyway. By contrast, *Note `CREATE TABLE ... SELECT': create-table-select. (without `IF NOT EXISTS') failed with an error, but MySQL inserted no rows and did not write the statement to the binary log. * MySQL now handles both statements the same way when the destination table exists, in that neither statement inserts rows or is written to the binary log. The difference between them is that MySQL produces a warning when `IF NOT EXISTS' is present and an error when it is not. This change means that, for the preceding example, the *Note `CREATE TABLE IF NOT EXISTS ... SELECT': create-table-select. statement inserts nothing into the destination table as of MySQL 5.5.6. This change in handling of `IF NOT EXISTS' results in an incompatibility for statement-based replication from a MySQL 5.1 master with the original behavior and a MySQL 5.5 slave with the new behavior. Suppose that *Note `CREATE TABLE IF NOT EXISTS ... SELECT': create-table-select. is executed on the master and the destination table exists. The result is that rows are inserted on the master but not on the slave. (Row-based replication does not have this problem.) To address this issue, statement-based binary logging for *Note `CREATE TABLE IF NOT EXISTS ... SELECT': create-table-select. is changed in MySQL 5.1 as of 5.1.51: * If the destination table does not exist, there is no change: The statement is logged as is. * If the destination table does exist, the statement is logged as the equivalent pair of *Note `CREATE TABLE IF NOT EXISTS': create-table-select. and *Note `INSERT ... SELECT': insert-select. statements. (If the *Note `SELECT': select. in the original statement is preceded by `IGNORE' or *Note `REPLACE': replace, the *Note `INSERT': insert. becomes *Note `INSERT IGNORE': insert. or *Note `REPLACE': replace, respectively.) This change provides forward compatibility for statement-based replication from MySQL 5.1 to 5.5 because when the destination table exists, the rows will be inserted on both the master and slave. To take advantage of this compatibility measure, the 5.1 server must be at least 5.1.51 and the 5.5 server must be at least 5.5.6. To upgrade an existing 5.1-to-5.5 replication scenario, upgrade the master first to 5.1.51 or higher. Note that this differs from the usual replication upgrade advice of upgrading the slave first. A workaround for applications that wish to achieve the original effect (rows inserted regardless of whether the destination table exists) is to use *Note `CREATE TABLE IF NOT EXISTS': create-table-select. and *Note `INSERT ... SELECT': insert-select. statements rather than *Note `CREATE TABLE IF NOT EXISTS ... SELECT': create-table-select. statements. Along with the change just described, the following related change was made: Previously, if an existing view was named as the destination table for *Note `CREATE TABLE IF NOT EXISTS ... SELECT': create-table-select, rows were inserted into the underlying base table and the statement was written to the binary log. As of MySQL 5.1.51 and 5.5.6, nothing is inserted or logged. To ensure that the binary log can be used to re-create the original tables, MySQL does not permit concurrent inserts during *Note `CREATE TABLE ... SELECT': create-table.  File: manual.info, Node: silent-column-changes, Prev: create-table-select, Up: create-table 13.1.17.2 Silent Column Specification Changes ............................................. In some cases, MySQL silently changes column specifications from those given in a *Note `CREATE TABLE': create-table. or *Note `ALTER TABLE': alter-table. statement. These might be changes to a data type, to attributes associated with a data type, or to an index specification. All changes are subject to the internal row-size limit of 65,535 bytes, which may cause some attempts at data type changes to fail. See *Note column-count-limit::. * *Note `TIMESTAMP': datetime. display sizes are discarded. Also note that *Note `TIMESTAMP': datetime. columns are `NOT NULL' by default. * Columns that are part of a `PRIMARY KEY' are made `NOT NULL' even if not declared that way. * Trailing spaces are automatically deleted from *Note `ENUM': enum. and *Note `SET': set. member values when the table is created. * MySQL maps certain data types used by other SQL database vendors to MySQL types. See *Note other-vendor-data-types::. * If you include a `USING' clause to specify an index type that is not legal for a given storage engine, but there is another index type available that the engine can use without affecting query results, the engine uses the available type. * If strict SQL mode is not enabled, a *Note `VARCHAR': char. column with a length specification greater than 65535 is converted to *Note `TEXT': blob, and a *Note `VARBINARY': binary-varbinary. column with a length specification greater than 65535 is converted to *Note `BLOB': blob. Otherwise, an error occurs in either of these cases. * Specifying the `CHARACTER SET binary' attribute for a character data type causes the column to be created as the corresponding binary data type: *Note `CHAR': char. becomes *Note `BINARY': binary-varbinary, *Note `VARCHAR': char. becomes *Note `VARBINARY': binary-varbinary, and *Note `TEXT': blob. becomes *Note `BLOB': blob. For the *Note `ENUM': enum. and *Note `SET': set. data types, this does not occur; they are created as declared. Suppose that you specify a table using this definition: CREATE TABLE t ( c1 VARCHAR(10) CHARACTER SET binary, c2 TEXT CHARACTER SET binary, c3 ENUM('a','b','c') CHARACTER SET binary ); The resulting table has this definition: CREATE TABLE t ( c1 VARBINARY(10), c2 BLOB, c3 ENUM('a','b','c') CHARACTER SET binary ); To see whether MySQL used a data type other than the one you specified, issue a *Note `DESCRIBE': describe. or *Note `SHOW CREATE TABLE': show-create-table. statement after creating or altering the table. Certain other data type changes can occur if you compress a table using *Note `myisampack': myisampack. See *Note compressed-format::.  File: manual.info, Node: create-tablespace, Next: create-trigger, Prev: create-table, Up: sql-syntax-data-definition 13.1.18 `CREATE TABLESPACE' Syntax ---------------------------------- CREATE TABLESPACE TABLESPACE_NAME ADD DATAFILE 'FILE_NAME' USE LOGFILE GROUP LOGFILE_GROUP [EXTENT_SIZE [=] EXTENT_SIZE] [INITIAL_SIZE [=] INITIAL_SIZE] [AUTOEXTEND_SIZE [=] AUTOEXTEND_SIZE] [MAX_SIZE [=] MAX_SIZE] [NODEGROUP [=] NODEGROUP_ID] [WAIT] [COMMENT [=] COMMENT_TEXT] ENGINE [=] ENGINE_NAME This statement is used to create a tablespace, which can contain one or more data files, providing storage space for tables. One data file is created and added to the tablespace using this statement. Additional data files may be added to the tablespace by using the *Note `ALTER TABLESPACE': alter-tablespace. statement (see *Note alter-tablespace::). For rules covering the naming of tablespaces, see *Note identifiers::. *Note*: All MySQL Cluster Disk Data objects share the same namespace. This means that _each Disk Data object_ must be uniquely named (and not merely each Disk Data object of a given type). For example, you cannot have a tablespace and a log file group with the same name, or a tablespace and a data file with the same name. Prior to MySQL Cluster NDB 6.2.17, 6.3.23, and 6.4.3, path and file names for data files could not be longer than 128 characters. (Bug#31770) A log file group of one or more `UNDO' log files must be assigned to the tablespace to be created with the `USE LOGFILE GROUP' clause. LOGFILE_GROUP must be an existing log file group created with *Note `CREATE LOGFILE GROUP': create-logfile-group. (see *Note create-logfile-group::). Multiple tablespaces may use the same log file group for `UNDO' logging. The `EXTENT_SIZE' sets the size, in bytes, of the extents used by any files belonging to the tablespace. The default value is 1M. The minimum size is 32K, and theoretical maximum is 2G, although the practical maximum size depends on a number of factors. In most cases, changing the extent size does not have any measurable effect on performance, and the default value is recommended for all but the most unusual situations. An _extent_ is a unit of disk space allocation. One extent is filled with as much data as that extent can contain before another extent is used. In theory, up to 65,535 (64K) extents may used per data file; however, the recommended maximum is 32,768 (32K). The recommended maximum size for a single data file is 32G--that is, 32K extents x 1 MB per extent. In addition, once an extent is allocated to a given partition, it cannot be used to store data from a different partition; an extent cannot store data from more than one partition. This means, for example that a tablespace having a single datafile whose `INITIAL_SIZE' is 256 MB and whose `EXTENT_SIZE' is 128M has just two extents, and so can be used to store data from at most two different disk data table partitions. You can see how many extents remain free in a given data file by querying the *Note `INFORMATION_SCHEMA.FILES': files-table. table, and so derive an estimate for how much space remains free in the file. For further discussion and examples, see *Note files-table::. The `INITIAL_SIZE' parameter sets the data file's total size in bytes. Once the file has been created, its size cannot be changed; however, you can add more data files to the tablespace using `ALTER TABLESPACE ... ADD DATAFILE'. See *Note alter-tablespace::. `INITIAL_SIZE' is optional; its default value is `128M'. On 32-bit systems, the maximum supported value for `INITIAL_SIZE' is `4G'. (Bug#29186) When setting `EXTENT_SIZE' or `INITIAL_SIZE' (either or both), you may optionally follow the number with a one-letter abbreviation for an order of magnitude, similar to those used in `my.cnf'. Generally, this is one of the letters `M' (for megabytes) or `G' (for gigabytes). `INITIAL_SIZE', `EXTENT_SIZE', and `UNDO_BUFFER_SIZE' are subject to rounding as follows: * `EXTENT_SIZE' and `UNDO_BUFFER_SIZE' are each rounded up to the nearest whole multiple of 32K. * `INITIAL_SIZE' is rounded _down_ to the nearest whole multiple of 32K. For data files, _INITIAL_SIZE_ is subject to further rounding; the result just obtained is rounded up to the nearest whole multiple of `EXTENT_SIZE' (after any rounding). The rounding just described has always (since Disk Data tablespaces were introduced in MySQL 5.1.6) been performed implicitly, but beginning with MySQL Cluster NDB 6.2.19, MySQL Cluster NDB 6.3.32, MySQL Cluster NDB 7.0.13, and MySQL Cluster NDB 7.1.2, this rounding is done explicitly, and a warning is issued by the MySQL Server when any such rounding is performed. The rounded values are also used by the NDB kernel for calculating *Note `INFORMATION_SCHEMA.FILES': files-table. column values and other purposes. However, to avoid an unexpected result, we suggest that you always use whole multiples of 32K in specifying these options. `AUTOEXTEND_SIZE', `MAX_SIZE', `NODEGROUP', `WAIT', and `COMMENT' are parsed but ignored, and so currently have no effect. These options are intended for future expansion. The `ENGINE' parameter determines the storage engine which uses this tablespace, with ENGINE_NAME being the name of the storage engine. In MySQL 5.1, ENGINE_NAME must be one of the values *Note `NDB': mysql-cluster. or *Note `NDBCLUSTER': mysql-cluster. When *Note `CREATE TABLESPACE': create-tablespace. is used with `ENGINE = NDB', a tablespace and associated data file are created on each Cluster data node. You can verify that the data files were created and obtain information about them by querying the *Note `INFORMATION_SCHEMA.FILES': files-table. table. For example: mysql> SELECT LOGFILE_GROUP_NAME, FILE_NAME, EXTRA -> FROM INFORMATION_SCHEMA.FILES -> WHERE TABLESPACE_NAME = 'newts' AND FILE_TYPE = 'DATAFILE'; +--------------------+-------------+----------------+ | LOGFILE_GROUP_NAME | FILE_NAME | EXTRA | +--------------------+-------------+----------------+ | lg_3 | newdata.dat | CLUSTER_NODE=3 | | lg_3 | newdata.dat | CLUSTER_NODE=4 | +--------------------+-------------+----------------+ 2 rows in set (0.01 sec) (See *Note files-table::.) *Note `CREATE TABLESPACE': create-tablespace. was added in MySQL 5.1.6. In MySQL 5.1, it is useful only with Disk Data storage for MySQL Cluster. See *Note mysql-cluster-disk-data::.  File: manual.info, Node: create-trigger, Next: create-view, Prev: create-tablespace, Up: sql-syntax-data-definition 13.1.19 `CREATE TRIGGER' Syntax ------------------------------- CREATE [DEFINER = { USER | CURRENT_USER }] TRIGGER TRIGGER_NAME TRIGGER_TIME TRIGGER_EVENT ON TBL_NAME FOR EACH ROW TRIGGER_BODY This statement creates a new trigger. A trigger is a named database object that is associated with a table, and that activates when a particular event occurs for the table. The trigger becomes associated with the table named TBL_NAME, which must refer to a permanent table. You cannot associate a trigger with a `TEMPORARY' table or a view. *Note `CREATE TRIGGER': create-trigger. requires the `TRIGGER' privilege for the table associated with the trigger. The statement might also require the `SUPER' privilege, depending on the `DEFINER' value, as described later in this section. If binary logging is enabled, *Note `CREATE TRIGGER': create-trigger. might require the `SUPER' privilege, as described in *Note stored-programs-logging::. (Before MySQL 5.1.6, there is no `TRIGGER' privilege and this statement requires the `SUPER' privilege in all cases.) The `DEFINER' clause determines the security context to be used when checking access privileges at trigger activation time. See later in this section for more information. TRIGGER_TIME is the trigger action time. It can be `BEFORE' or `AFTER' to indicate that the trigger activates before or after each row to be modified. TRIGGER_EVENT indicates the kind of statement that activates the trigger. The TRIGGER_EVENT can be one of the following: * *Note `INSERT': insert.: The trigger is activated whenever a new row is inserted into the table; for example, through *Note `INSERT': insert, *Note `LOAD DATA': load-data, and *Note `REPLACE': replace. statements. * *Note `UPDATE': update.: The trigger is activated whenever a row is modified; for example, through *Note `UPDATE': update. statements. * *Note `DELETE': delete.: The trigger is activated whenever a row is deleted from the table; for example, through *Note `DELETE': delete. and *Note `REPLACE': replace. statements. However, *Note `DROP TABLE': drop-table. and *Note `TRUNCATE TABLE': truncate-table. statements on the table do _not_ activate this trigger, because they do not use *Note `DELETE': delete. Dropping a partition does not activate *Note `DELETE': delete. triggers, either. See *Note truncate-table::. It is important to understand that the TRIGGER_EVENT does not represent a literal type of SQL statement that activates the trigger so much as it represents a type of table operation. For example, an *Note `INSERT': insert. trigger is activated by not only *Note `INSERT': insert. statements but also *Note `LOAD DATA': load-data. statements because both statements insert rows into a table. A potentially confusing example of this is the `INSERT INTO ... ON DUPLICATE KEY UPDATE ...' syntax: a `BEFORE INSERT' trigger will activate for every row, followed by either an `AFTER INSERT' trigger or both the `BEFORE UPDATE' and `AFTER UPDATE' triggers, depending on whether there was a duplicate key for the row. There cannot be two triggers for a given table that have the same trigger action time and event. For example, you cannot have two `BEFORE UPDATE' triggers for a table. But you can have a `BEFORE UPDATE' and a `BEFORE INSERT' trigger, or a `BEFORE UPDATE' and an `AFTER UPDATE' trigger. TRIGGER_BODY is the statement to execute when the trigger activates. If you want to execute multiple statements, use the *Note `BEGIN ... END': begin-end. compound statement construct. This also enables you to use the same statements that are permissible within stored routines. See *Note begin-end::. Some statements are not permitted in triggers; see *Note stored-program-restrictions::. You can refer to columns in the subject table (the table associated with the trigger) by using the aliases `OLD' and `NEW'. `OLD.COL_NAME' refers to a column of an existing row before it is updated or deleted. `NEW.COL_NAME' refers to the column of a new row to be inserted or an existing row after it is updated. MySQL stores the `sql_mode' system variable setting that is in effect at the time a trigger is created, and always executes the trigger with this setting in force, _regardless of the server SQL mode in effect when the event begins executing_. *Note*: Currently, cascaded foreign key actions do not activate triggers. The `DEFINER' clause specifies the MySQL account to be used when checking access privileges at trigger activation time. If a USER value is given, it should be a MySQL account specified as `'USER_NAME'@'HOST_NAME'' (the same format used in the *Note `GRANT': grant. statement), `CURRENT_USER', or `CURRENT_USER()'. The default `DEFINER' value is the user who executes the *Note `CREATE TRIGGER': create-trigger. statement. This is the same as specifying `DEFINER = CURRENT_USER' explicitly. If you specify the `DEFINER' clause, these rules determine the legal `DEFINER' user values: * If you do not have the `SUPER' privilege, the only legal USER value is your own account, either specified literally or by using `CURRENT_USER'. You cannot set the definer to some other account. * If you have the `SUPER' privilege, you can specify any syntactically legal account name. If the account does not actually exist, a warning is generated. * Although it is possible to create a trigger with a nonexistent `DEFINER' account, it is not a good idea for such triggers to be activated until the account actually does exist. Otherwise, the behavior with respect to privilege checking is undefined. Note: Prior to MySQL 5.1.6, *Note `CREATE TRIGGER': create-trigger. always requires the `SUPER' privilege, so only the second of the preceding rules applies. MySQL takes the `DEFINER' user into account when checking trigger privileges as follows: * At *Note `CREATE TRIGGER': create-trigger. time, the user who issues the statement must have the `TRIGGER' privilege. (`SUPER' prior to MySQL 5.1.6.) * At trigger activation time, privileges are checked against the `DEFINER' user. This user must have these privileges: * The `TRIGGER' privilege. (`SUPER' prior to MySQL 5.1.6.) * The `SELECT' privilege for the subject table if references to table columns occur using `OLD.COL_NAME' or `NEW.COL_NAME' in the trigger definition. * The `UPDATE' privilege for the subject table if table columns are targets of `SET NEW.COL_NAME = VALUE' assignments in the trigger definition. * Whatever other privileges normally are required for the statements executed by the trigger. For more information about trigger security, see *Note stored-programs-security::. Within a trigger, the `CURRENT_USER()' function returns the account used to check privileges at trigger activation time. This is the `DEFINER' user, not the user whose actions caused the trigger to be activated. For information about user auditing within triggers, see *Note account-activity-auditing::. If you use *Note `LOCK TABLES': lock-tables. to lock a table that has triggers, the tables used within the trigger are also locked, as described in *Note lock-tables-and-triggers::. In MySQL 5.1, you can write triggers containing direct references to tables by name, such as the trigger named `testref' shown in this example: CREATE TABLE test1(a1 INT); CREATE TABLE test2(a2 INT); CREATE TABLE test3(a3 INT NOT NULL AUTO_INCREMENT PRIMARY KEY); CREATE TABLE test4( a4 INT NOT NULL AUTO_INCREMENT PRIMARY KEY, b4 INT DEFAULT 0 ); delimiter | CREATE TRIGGER testref BEFORE INSERT ON test1 FOR EACH ROW BEGIN INSERT INTO test2 SET a2 = NEW.a1; DELETE FROM test3 WHERE a3 = NEW.a1; UPDATE test4 SET b4 = b4 + 1 WHERE a4 = NEW.a1; END; | delimiter ; INSERT INTO test3 (a3) VALUES (NULL), (NULL), (NULL), (NULL), (NULL), (NULL), (NULL), (NULL), (NULL), (NULL); INSERT INTO test4 (a4) VALUES (0), (0), (0), (0), (0), (0), (0), (0), (0), (0); Suppose that you insert the following values into table `test1' as shown here: mysql> INSERT INTO test1 VALUES -> (1), (3), (1), (7), (1), (8), (4), (4); Query OK, 8 rows affected (0.01 sec) Records: 8 Duplicates: 0 Warnings: 0 As a result, the data in the four tables will be as follows: mysql> SELECT * FROM test1; +------+ | a1 | +------+ | 1 | | 3 | | 1 | | 7 | | 1 | | 8 | | 4 | | 4 | +------+ 8 rows in set (0.00 sec) mysql> SELECT * FROM test2; +------+ | a2 | +------+ | 1 | | 3 | | 1 | | 7 | | 1 | | 8 | | 4 | | 4 | +------+ 8 rows in set (0.00 sec) mysql> SELECT * FROM test3; +----+ | a3 | +----+ | 2 | | 5 | | 6 | | 9 | | 10 | +----+ 5 rows in set (0.00 sec) mysql> SELECT * FROM test4; +----+------+ | a4 | b4 | +----+------+ | 1 | 3 | | 2 | 0 | | 3 | 1 | | 4 | 2 | | 5 | 0 | | 6 | 0 | | 7 | 1 | | 8 | 1 | | 9 | 0 | | 10 | 0 | +----+------+ 10 rows in set (0.00 sec)  File: manual.info, Node: create-view, Next: drop-database, Prev: create-trigger, Up: sql-syntax-data-definition 13.1.20 `CREATE VIEW' Syntax ---------------------------- CREATE [OR REPLACE] [ALGORITHM = {UNDEFINED | MERGE | TEMPTABLE}] [DEFINER = { USER | CURRENT_USER }] [SQL SECURITY { DEFINER | INVOKER }] VIEW VIEW_NAME [(COLUMN_LIST)] AS SELECT_STATEMENT [WITH [CASCADED | LOCAL] CHECK OPTION] The *Note `CREATE VIEW': create-view. statement creates a new view, or replaces an existing one if the `OR REPLACE' clause is given. If the view does not exist, *Note `CREATE OR REPLACE VIEW': create-view. is the same as *Note `CREATE VIEW': create-view. If the view does exist, *Note `CREATE OR REPLACE VIEW': create-view. is the same as *Note `ALTER VIEW': alter-view. The SELECT_STATEMENT is a *Note `SELECT': select. statement that provides the definition of the view. (When you select from the view, you select in effect using the *Note `SELECT': select. statement.) SELECT_STATEMENT can select from base tables or other views. The view definition is `frozen' at creation time, so changes to the underlying tables afterward do not affect the view definition. For example, if a view is defined as `SELECT *' on a table, new columns added to the table later do not become part of the view. The `ALGORITHM' clause affects how MySQL processes the view. The `DEFINER' and `SQL SECURITY' clauses specify the security context to be used when checking access privileges at view invocation time. The `WITH CHECK OPTION' clause can be given to constrain inserts or updates to rows in tables referenced by the view. These clauses are described later in this section. The *Note `CREATE VIEW': create-view. statement requires the `CREATE VIEW' privilege for the view, and some privilege for each column selected by the *Note `SELECT': select. statement. For columns used elsewhere in the *Note `SELECT': select. statement you must have the `SELECT' privilege. If the `OR REPLACE' clause is present, you must also have the `DROP' privilege for the view. *Note `CREATE VIEW': create-view. might also require the `SUPER' privilege, depending on the `DEFINER' value, as described later in this section. When a view is referenced, privilege checking occurs as described later in this section. A view belongs to a database. By default, a new view is created in the default database. To create the view explicitly in a given database, specify the name as DB_NAME.VIEW_NAME when you create it: mysql> CREATE VIEW test.v AS SELECT * FROM t; Within a database, base tables and views share the same namespace, so a base table and a view cannot have the same name. Columns retrieved by the *Note `SELECT': select. statement can be simple references to table columns. They can also be expressions that use functions, constant values, operators, and so forth. Views must have unique column names with no duplicates, just like base tables. By default, the names of the columns retrieved by the *Note `SELECT': select. statement are used for the view column names. To define explicit names for the view columns, the optional COLUMN_LIST clause can be given as a list of comma-separated identifiers. The number of names in COLUMN_LIST must be the same as the number of columns retrieved by the *Note `SELECT': select. statement. *Note*: Prior to MySQL 5.1.29, when you modify an existing view, the server saves a backup of the current view definition under the view database directory, in a subdirectory named `arc'. The backup file for a view `v' is named `v.frm-00001'. If you alter the view again, the next backup is named `v.frm-00002'. The three latest view backup definitions are stored. Backed up view definitions are not preserved by *Note `mysqldump': mysqldump, or any other such programs, but you can retain them using a file copy operation. However, they are not needed for anything but to provide you with a backup of your previous view definition. It is safe to remove these backup definitions, but only while *Note `mysqld': mysqld. is not running. If you delete the `arc' subdirectory or its files while *Note `mysqld': mysqld. is running, an error occurs the next time you try to alter the view: mysql> ALTER VIEW v AS SELECT * FROM t; ERROR 6 (HY000): Error on delete of '.\test\arc/v.frm-0004' (Errcode: 2) Unqualified table or view names in the *Note `SELECT': select. statement are interpreted with respect to the default database. A view can refer to tables or views in other databases by qualifying the table or view name with the proper database name. A view can be created from many kinds of *Note `SELECT': select. statements. It can refer to base tables or other views. It can use joins, *Note `UNION': union, and subqueries. The *Note `SELECT': select. need not even refer to any tables. The following example defines a view that selects two columns from another table, as well as an expression calculated from those columns: mysql> CREATE TABLE t (qty INT, price INT); mysql> INSERT INTO t VALUES(3, 50); mysql> CREATE VIEW v AS SELECT qty, price, qty*price AS value FROM t; mysql> SELECT * FROM v; +------+-------+-------+ | qty | price | value | +------+-------+-------+ | 3 | 50 | 150 | +------+-------+-------+ A view definition is subject to the following restrictions: * The *Note `SELECT': select. statement cannot contain a subquery in the `FROM' clause. * The *Note `SELECT': select. statement cannot refer to system or user variables. * Within a stored program, the definition cannot refer to program parameters or local variables. * The *Note `SELECT': select. statement cannot refer to prepared statement parameters. * Any table or view referred to in the definition must exist. However, after a view has been created, it is possible to drop a table or view that the definition refers to. In this case, use of the view results in an error. To check a view definition for problems of this kind, use the *Note `CHECK TABLE': check-table. statement. * The definition cannot refer to a `TEMPORARY' table, and you cannot create a `TEMPORARY' view. * Any tables named in the view definition must exist at definition time. * You cannot associate a trigger with a view. * As of MySQL 5.1.23, aliases for column names in the *Note `SELECT': select. statement are checked against the maximum column length of 64 characters (not the maximum alias length of 256 characters). `ORDER BY' is permitted in a view definition, but it is ignored if you select from a view using a statement that has its own `ORDER BY'. For other options or clauses in the definition, they are added to the options or clauses of the statement that references the view, but the effect is undefined. For example, if a view definition includes a `LIMIT' clause, and you select from the view using a statement that has its own `LIMIT' clause, it is undefined which limit applies. This same principle applies to options such as `ALL', `DISTINCT', or `SQL_SMALL_RESULT' that follow the *Note `SELECT': select. keyword, and to clauses such as `INTO', `FOR UPDATE', `LOCK IN SHARE MODE', and `PROCEDURE'. If you create a view and then change the query processing environment by changing system variables, that may affect the results that you get from the view: mysql> CREATE VIEW v (mycol) AS SELECT 'abc'; Query OK, 0 rows affected (0.01 sec) mysql> SET sql_mode = ''; Query OK, 0 rows affected (0.00 sec) mysql> SELECT "mycol" FROM v; +-------+ | mycol | +-------+ | mycol | +-------+ 1 row in set (0.01 sec) mysql> SET sql_mode = 'ANSI_QUOTES'; Query OK, 0 rows affected (0.00 sec) mysql> SELECT "mycol" FROM v; +-------+ | mycol | +-------+ | abc | +-------+ 1 row in set (0.00 sec) The `DEFINER' and `SQL SECURITY' clauses determine which MySQL account to use when checking access privileges for the view when a statement is executed that references the view. These clauses were addded in MySQL 5.1.2. The legal `SQL SECURITY' characteristic values are `DEFINER' and `INVOKER'. These indicate that the required privileges must be held by the user who defined or invoked the view, respectively. The default `SQL SECURITY' value is `DEFINER'. If a USER value is given for the `DEFINER' clause, it should be a MySQL account specified as `'USER_NAME'@'HOST_NAME'' (the same format used in the *Note `GRANT': grant. statement), `CURRENT_USER', or `CURRENT_USER()'. The default `DEFINER' value is the user who executes the *Note `CREATE VIEW': create-view. statement. This is the same as specifying `DEFINER = CURRENT_USER' explicitly. If you specify the `DEFINER' clause, these rules determine the legal `DEFINER' user values: * If you do not have the `SUPER' privilege, the only legal USER value is your own account, either specified literally or by using `CURRENT_USER'. You cannot set the definer to some other account. * If you have the `SUPER' privilege, you can specify any syntactically legal account name. If the account does not actually exist, a warning is generated. * Although it is possible to create a view with a nonexistent `DEFINER' account, an error occurs when the view is referenced if the `SQL SECURITY' value is `DEFINER' but the definer account does not exist. For more information about view security, see *Note stored-programs-security::. Within a view definition, `CURRENT_USER' returns the view's `DEFINER' value by default as of MySQL 5.1.12. For older versions, and for views defined with the `SQL SECURITY INVOKER' characteristic, `CURRENT_USER' returns the account for the view's invoker. For information about user auditing within views, see *Note account-activity-auditing::. Within a stored routine that is defined with the `SQL SECURITY DEFINER' characteristic, `CURRENT_USER' returns the routine's `DEFINER' value. This also affects a view defined within such a routine, if the view definition contains a `DEFINER' value of `CURRENT_USER'. As of MySQL 5.1.2 (when the `DEFINER' and `SQL SECURITY' clauses were implemented), view privileges are checked like this: * At view definition time, the view creator must have the privileges needed to use the top-level objects accessed by the view. For example, if the view definition refers to table columns, the creator must have some privilege for each column in the select list of the definition, and the `SELECT' privilege for each column used elsewhere in the definition. If the definition refers to a stored function, only the privileges needed to invoke the function can be checked. The privileges required at function invocation time can be checked only as it executes: For different invocations, different execution paths within the function might be taken. * The user who references a view must have appropriate privileges to access it (`SELECT' to select from it, `INSERT' to insert into it, and so forth.) * When a view has been referenced, privileges for objects accessed by the view are checked against the privileges held by the view `DEFINER' account or invoker, depending on whether the `SQL SECURITY' characteristic is `DEFINER' or `INVOKER', respectively. * If reference to a view causes execution of a stored function, privilege checking for statements executed within the function depend on whether the function `SQL SECURITY' characteristic is `DEFINER' or `INVOKER'. If the security characteristic is `DEFINER', the function runs with the privileges of the `DEFINER' account. If the characteristic is `INVOKER', the function runs with the privileges determined by the view's `SQL SECURITY' characteristic. Prior to MySQL 5.1.2 (before the `DEFINER' and `SQL SECURITY' clauses were implemented), privileges required for objects used in a view are checked at view creation time. Example: A view might depend on a stored function, and that function might invoke other stored routines. For example, the following view invokes a stored function `f()': CREATE VIEW v AS SELECT * FROM t WHERE t.id = f(t.name); Suppose that `f()' contains a statement such as this: IF name IS NULL then CALL p1(); ELSE CALL p2(); END IF; The privileges required for executing statements within `f()' need to be checked when `f()' executes. This might mean that privileges are needed for `p1()' or `p2()', depending on the execution path within `f()'. Those privileges must be checked at runtime, and the user who must possess the privileges is determined by the `SQL SECURITY' values of the view `v' and the function `f()'. The `DEFINER' and `SQL SECURITY' clauses for views are extensions to standard SQL. In standard SQL, views are handled using the rules for `SQL SECURITY DEFINER'. The standard says that the definer of the view, which is the same as the owner of the view's schema, gets applicable privileges on the view (for example, `SELECT') and may grant them. MySQL has no concept of a schema `owner', so MySQL adds a clause to identify the definer. The `DEFINER' clause is an extension where the intent is to have what the standard has; that is, a permanent record of who defined the view. This is why the default `DEFINER' value is the account of the view creator. If you invoke a view that was created before MySQL 5.1.2, it is treated as though it was created with a `SQL SECURITY DEFINER' characteristic and with a `DEFINER' value that is the same as your account. However, because the actual definer is unknown, MySQL issues a warning. To eliminate the warning, it is sufficient to re-create the view so that the view definition includes a `DEFINER' clause. The optional `ALGORITHM' clause is a MySQL extension to standard SQL. It affects how MySQL processes the view. `ALGORITHM' takes three values: `MERGE', `TEMPTABLE', or `UNDEFINED'. The default algorithm is `UNDEFINED' if no `ALGORITHM' clause is present. For more information, see *Note view-algorithms::. Some views are updatable. That is, you can use them in statements such as *Note `UPDATE': update, *Note `DELETE': delete, or *Note `INSERT': insert. to update the contents of the underlying table. For a view to be updatable, there must be a one-to-one relationship between the rows in the view and the rows in the underlying table. There are also certain other constructs that make a view nonupdatable. The `WITH CHECK OPTION' clause can be given for an updatable view to prevent inserts or updates to rows except those for which the `WHERE' clause in the SELECT_STATEMENT is true. In a `WITH CHECK OPTION' clause for an updatable view, the `LOCAL' and `CASCADED' keywords determine the scope of check testing when the view is defined in terms of another view. The `LOCAL' keyword restricts the `CHECK OPTION' only to the view being defined. `CASCADED' causes the checks for underlying views to be evaluated as well. When neither keyword is given, the default is `CASCADED'. For more information about updatable views and the `WITH CHECK OPTION' clause, see *Note view-updatability::.  File: manual.info, Node: drop-database, Next: drop-event, Prev: create-view, Up: sql-syntax-data-definition 13.1.21 `DROP DATABASE' Syntax ------------------------------ DROP {DATABASE | SCHEMA} [IF EXISTS] DB_NAME *Note `DROP DATABASE': drop-database. drops all tables in the database and deletes the database. Be _very_ careful with this statement! To use *Note `DROP DATABASE': drop-database, you need the `DROP' privilege on the database. *Note `DROP SCHEMA': drop-database. is a synonym for *Note `DROP DATABASE': drop-database. *Important*: When a database is dropped, user privileges on the database are _not_ automatically dropped. See *Note grant::. `IF EXISTS' is used to prevent an error from occurring if the database does not exist. If the default database is dropped, the default database is unset (the `DATABASE()' function returns `NULL'). If you use *Note `DROP DATABASE': drop-database. on a symbolically linked database, both the link and the original database are deleted. *Note `DROP DATABASE': drop-database. returns the number of tables that were removed. This corresponds to the number of `.frm' files removed. The *Note `DROP DATABASE': drop-database. statement removes from the given database directory those files and directories that MySQL itself may create during normal operation: * All files with the following extensions. `.BAK' `.DAT' `.HSH' `.MRG' `.MYD' `.MYI' `.TRG' `.TRN' `.db' `.frm' `.ibd' `.ndb' `.par' * The `db.opt' file, if it exists. If other files or directories remain in the database directory after MySQL removes those just listed, the database directory cannot be removed. In this case, you must remove any remaining files or directories manually and issue the *Note `DROP DATABASE': drop-database. statement again. You can also drop databases with *Note `mysqladmin': mysqladmin. See *Note mysqladmin::.  File: manual.info, Node: drop-event, Next: drop-function, Prev: drop-database, Up: sql-syntax-data-definition 13.1.22 `DROP EVENT' Syntax --------------------------- DROP EVENT [IF EXISTS] EVENT_NAME This statement drops the event named EVENT_NAME. The event immediately ceases being active, and is deleted completely from the server. If the event does not exist, the error `ERROR 1517 (HY000): Unknown event 'EVENT_NAME'' results. You can override this and cause the statement to generate a warning for nonexistent events instead using `IF EXISTS'. Beginning with MySQL 5.1.12, this statement requires the `EVENT' privilege for the schema to which the event to be dropped belongs. (In MySQL 5.1.11 and earlier, an event could be dropped only by its definer, or by a user having the `SUPER' privilege.)  File: manual.info, Node: drop-function, Next: drop-index, Prev: drop-event, Up: sql-syntax-data-definition 13.1.23 `DROP FUNCTION' Syntax ------------------------------ The *Note `DROP FUNCTION': drop-function. statement is used to drop stored functions and user-defined functions (UDFs): * For information about dropping stored functions, see *Note drop-procedure::. * For information about dropping user-defined functions, see *Note drop-function-udf::.  File: manual.info, Node: drop-index, Next: drop-logfile-group, Prev: drop-function, Up: sql-syntax-data-definition 13.1.24 `DROP INDEX' Syntax --------------------------- DROP [ONLINE|OFFLINE] INDEX INDEX_NAME ON TBL_NAME *Note `DROP INDEX': drop-index. drops the index named INDEX_NAME from the table TBL_NAME. This statement is mapped to an *Note `ALTER TABLE': alter-table. statement to drop the index. See *Note alter-table::. Beginning with MySQL 5.1.17, indexes on variable-width columns of *Note `NDBCLUSTER': mysql-cluster. tables are dropped without any table copying. The table is not locked against access from other MySQL Cluster API nodes, although it is locked against other operations on the _same_ API node for the duration of the operation. This is done automatically by the server whenever it determines that it is possible to do so; you do not have to use any special SQL syntax or server options to cause it to happen. In standard MySQL 5.1 releases, it is not possible to override the server when it determines that an index is to be dropped without table copying. In MySQL Cluster, beginning with MySQL Cluster NDB 6.2.5 and MySQL Cluster NDB 6.3.3, you can drop indexes offline (which causes the table to be locked for all API nodes in the cluster) using the `OFFLINE' keyword. The rules and limitations governing `DROP OFFLINE INDEX' and `DROP ONLINE INDEX' are the same as for `ALTER OFFLINE TABLE ... DROP INDEX' and `ALTER ONLINE TABLE ... DROP INDEX'. You cannot cause the noncopying dropping of an index that would normally be dropped offline by using the `ONLINE' keyword (if it is not possible to perform the `DROP' operation without table copying, the `ONLINE' keyword is ignored). For more information, see *Note alter-table-online-operations::. *Note*: The `ONLINE' and `OFFLINE' keywords are available only in MySQL Cluster NDB 6.2.5, 6.3.3, and later MySQL Cluster releases; attempting to use these keywords in earlier MySQL Cluster releases or standard MySQL 5.1 releases results in a syntax error.  File: manual.info, Node: drop-logfile-group, Next: drop-procedure, Prev: drop-index, Up: sql-syntax-data-definition 13.1.25 `DROP LOGFILE GROUP' Syntax ----------------------------------- DROP LOGFILE GROUP LOGFILE_GROUP ENGINE [=] ENGINE_NAME This statement drops the log file group named LOGFILE_GROUP. The log file group must already exist or an error results. (For information on creating log file groups, see *Note create-logfile-group::.) *Important*: Before dropping a log file group, you must drop all tablespaces that use that log file group for `UNDO' logging. The required `ENGINE' clause provides the name of the storage engine used by the log file group to be dropped. In MySQL 5.1, the only permitted values for ENGINE_NAME are *Note `NDB': mysql-cluster. and *Note `NDBCLUSTER': mysql-cluster. *Note `DROP LOGFILE GROUP': drop-logfile-group. was added in MySQL 5.1.6. In MySQL 5.1, it is useful only with Disk Data storage for MySQL Cluster. See *Note mysql-cluster-disk-data::.  File: manual.info, Node: drop-procedure, Next: drop-server, Prev: drop-logfile-group, Up: sql-syntax-data-definition 13.1.26 `DROP PROCEDURE' and `DROP FUNCTION' Syntax --------------------------------------------------- DROP {PROCEDURE | FUNCTION} [IF EXISTS] SP_NAME This statement is used to drop a stored procedure or function. That is, the specified routine is removed from the server. You must have the `ALTER ROUTINE' privilege for the routine. (If the `automatic_sp_privileges' system variable is enabled, that privilege and `EXECUTE' are granted automatically to the routine creator when the routine is created and dropped from the creator when the routine is dropped. See *Note stored-routines-privileges::.) The `IF EXISTS' clause is a MySQL extension. It prevents an error from occurring if the procedure or function does not exist. A warning is produced that can be viewed with *Note `SHOW WARNINGS': show-warnings. *Note `DROP FUNCTION': drop-function. is also used to drop user-defined functions (see *Note drop-function-udf::).  File: manual.info, Node: drop-server, Next: drop-table, Prev: drop-procedure, Up: sql-syntax-data-definition 13.1.27 `DROP SERVER' Syntax ---------------------------- DROP SERVER [ IF EXISTS ] SERVER_NAME Drops the server definition for the server named `SERVER_NAME'. The corresponding row within the `mysql.servers' table will be deleted. This statement requires the `SUPER' privilege. Dropping a server for a table does not affect any `FEDERATED' tables that used this connection information when they were created. See *Note create-server::. *Note `DROP SERVER': drop-server. does not cause an automatic commit. *Note `DROP SERVER': drop-server. was added in MySQL 5.1.15.  File: manual.info, Node: drop-table, Next: drop-tablespace, Prev: drop-server, Up: sql-syntax-data-definition 13.1.28 `DROP TABLE' Syntax --------------------------- DROP [TEMPORARY] TABLE [IF EXISTS] TBL_NAME [, TBL_NAME] ... [RESTRICT | CASCADE] *Note `DROP TABLE': drop-table. removes one or more tables. You must have the `DROP' privilege for each table. All table data and the table definition are _removed_, so _be careful_ with this statement! If any of the tables named in the argument list do not exist, MySQL returns an error indicating by name which nonexisting tables it was unable to drop, but it also drops all of the tables in the list that do exist. *Important*: When a table is dropped, user privileges on the table are _not_ automatically dropped. See *Note grant::. Note that for a partitioned table, *Note `DROP TABLE': drop-table. permanently removes the table definition, all of its partitions, and all of the data which was stored in those partitions. It also removes the partitioning definition (`.par') file associated with the dropped table. Use `IF EXISTS' to prevent an error from occurring for tables that do not exist. A `NOTE' is generated for each nonexistent table when using `IF EXISTS'. See *Note show-warnings::. `RESTRICT' and `CASCADE' are permitted to make porting easier. In MySQL 5.1, they do nothing. *Note*: *Note `DROP TABLE': drop-table. automatically commits the current active transaction, unless you use the `TEMPORARY' keyword. The `TEMPORARY' keyword has the following effects: * The statement drops only `TEMPORARY' tables. * The statement does not end an ongoing transaction. * No access rights are checked. (A `TEMPORARY' table is visible only to the session that created it, so no check is necessary.) Using `TEMPORARY' is a good way to ensure that you do not accidentally drop a non-`TEMPORARY' table.  File: manual.info, Node: drop-tablespace, Next: drop-trigger, Prev: drop-table, Up: sql-syntax-data-definition 13.1.29 `DROP TABLESPACE' Syntax -------------------------------- DROP TABLESPACE TABLESPACE_NAME ENGINE [=] ENGINE_NAME This statement drops a tablespace that was previously created using *Note `CREATE TABLESPACE': create-tablespace. (see *Note create-tablespace::). *Important*: The tablespace to be dropped must not contain any data files; in other words, before you can drop a tablespace, you must first drop each of its data files using `ALTER TABLESPACE ... DROP DATAFILE' (see *Note alter-tablespace::). The `ENGINE' clause (required) specifies the storage engine used by the tablespace. In MySQL 5.1, the only accepted values for ENGINE_NAME are *Note `NDB': mysql-cluster. and *Note `NDBCLUSTER': mysql-cluster. *Note `DROP TABLESPACE': drop-tablespace. was added in MySQL 5.1.6. In MySQL 5.1, it is useful only with Disk Data storage for MySQL Cluster. See *Note mysql-cluster-disk-data::.  File: manual.info, Node: drop-trigger, Next: drop-view, Prev: drop-tablespace, Up: sql-syntax-data-definition 13.1.30 `DROP TRIGGER' Syntax ----------------------------- DROP TRIGGER [IF EXISTS] [SCHEMA_NAME.]TRIGGER_NAME This statement drops a trigger. The schema (database) name is optional. If the schema is omitted, the trigger is dropped from the default schema. *Note `DROP TRIGGER': drop-trigger. requires the `TRIGGER' privilege for the table associated with the trigger. (This statement requires the `SUPER' privilege prior to MySQL 5.1.6.) Use `IF EXISTS' to prevent an error from occurring for a trigger that does not exist. A `NOTE' is generated for a nonexistent trigger when using `IF EXISTS'. See *Note show-warnings::. The `IF EXISTS' clause was added in MySQL 5.1.14. Triggers for a table are also dropped if you drop the table. *Note*: When upgrading from a version of MySQL older than MySQL 5.0.10 to 5.0.10 or newer--including all MySQL 5.1 releases--you must drop all triggers and re-create them. Otherwise, *Note `DROP TRIGGER': drop-trigger. does not work for older triggers after the upgrade. See *Note upgrading-from-previous-series::, for a suggested upgrade procedure.  File: manual.info, Node: drop-view, Next: rename-database, Prev: drop-trigger, Up: sql-syntax-data-definition 13.1.31 `DROP VIEW' Syntax -------------------------- DROP VIEW [IF EXISTS] VIEW_NAME [, VIEW_NAME] ... [RESTRICT | CASCADE] *Note `DROP VIEW': drop-view. removes one or more views. You must have the `DROP' privilege for each view. If any of the views named in the argument list do not exist, MySQL returns an error indicating by name which nonexisting views it was unable to drop, but it also drops all of the views in the list that do exist. The `IF EXISTS' clause prevents an error from occurring for views that don't exist. When this clause is given, a `NOTE' is generated for each nonexistent view. See *Note show-warnings::. `RESTRICT' and `CASCADE', if given, are parsed and ignored.  File: manual.info, Node: rename-database, Next: rename-table, Prev: drop-view, Up: sql-syntax-data-definition 13.1.32 `RENAME DATABASE' Syntax -------------------------------- RENAME {DATABASE | SCHEMA} DB_NAME TO NEW_DB_NAME; This statement was added in MySQL 5.1.7 but was found to be dangerous and was removed in MySQL 5.1.23. It was intended to enable upgrading pre-5.1 databases to use the encoding implemented in 5.1 for mapping database names to database directory names (see *Note identifier-mapping::). However, use of this statement could result in loss of database contents, which is why it was removed. Do not use `RENAME DATABASE' in earlier versions in which it is present. To perform the task of upgrading database names with the new encoding, use `ALTER DATABASE DB_NAME UPGRADE DATA DIRECTORY NAME' instead (see *Note alter-database::).  File: manual.info, Node: rename-table, Next: truncate-table, Prev: rename-database, Up: sql-syntax-data-definition 13.1.33 `RENAME TABLE' Syntax ----------------------------- RENAME TABLE TBL_NAME TO NEW_TBL_NAME [, TBL_NAME2 TO NEW_TBL_NAME2] ... This statement renames one or more tables. The rename operation is done atomically, which means that no other session can access any of the tables while the rename is running. For example, if you have an existing table `old_table', you can create another table `new_table' that has the same structure but is empty, and then replace the existing table with the empty one as follows (assuming that `backup_table' does not already exist): CREATE TABLE new_table (...); RENAME TABLE old_table TO backup_table, new_table TO old_table; If the statement renames more than one table, renaming operations are done from left to right. If you want to swap two table names, you can do so like this (assuming that `tmp_table' does not already exist): RENAME TABLE old_table TO tmp_table, new_table TO old_table, tmp_table TO new_table; As long as two databases are on the same file system, you can use *Note `RENAME TABLE': rename-table. to move a table from one database to another: RENAME TABLE CURRENT_DB.TBL_NAME TO OTHER_DB.TBL_NAME; If there are any triggers associated with a table which is moved to a different database using *Note `RENAME TABLE': rename-table, then the statement fails with the error `Trigger in wrong schema'. *Note `RENAME TABLE': rename-table. also works for views, as long as you do not try to rename a view into a different database. Any privileges granted specifically for the renamed table or view are not migrated to the new name. They must be changed manually. When you execute `RENAME', you cannot have any locked tables or active transactions. You must also have the `ALTER' and `DROP' privileges on the original table, and the `CREATE' and `INSERT' privileges on the new table. If MySQL encounters any errors in a multiple-table rename, it does a reverse rename for all renamed tables to return everything to its original state. You cannot use `RENAME' to rename a `TEMPORARY' table. However, you can use *Note `ALTER TABLE': alter-table. instead: mysql> ALTER TABLE orig_name RENAME new_name;  File: manual.info, Node: truncate-table, Prev: rename-table, Up: sql-syntax-data-definition 13.1.34 `TRUNCATE TABLE' Syntax ------------------------------- TRUNCATE [TABLE] TBL_NAME *Note `TRUNCATE TABLE': truncate-table. empties a table completely. It requires the `DROP' privilege as of MySQL 5.1.16. (Before 5.1.16, it requires the `DELETE' privilege). Logically, *Note `TRUNCATE TABLE': truncate-table. is equivalent to a *Note `DELETE': delete. statement that deletes all rows, but there are practical differences under some circumstances. For an `InnoDB' table: * If there are no `FOREIGN KEY' constraints, `InnoDB' performs fast truncation by dropping the original table and creating an empty one with the same definition, which is much faster than deleting rows one by one. * When you use this fast truncation technique with the `innodb_file_per_table' option enabled, the operating system can reuse the freed disk space. For users of the InnoDB Plugin, the space is reclaimed automatically, as decribed in TRUNCATE TABLE Reclaims Space (http://dev.mysql.com/doc/innodb-plugin/1.0/en/innodb-other-changes-truncate.html). If you do not have the InnoDB Plugin installed, issue the *Note `OPTIMIZE TABLE': optimize-table. statement to free the disk space for the table. * If there are any `FOREIGN KEY' constraints that reference the table, `InnoDB' processes *Note `TRUNCATE TABLE': truncate-table. by deleting rows one by one, processing the constraints as it proceeds. If the `FOREIGN KEY' constraint specifies `DELETE CASCADE', rows from the child (referenced) table are deleted, and the truncated table becomes empty. If the `FOREIGN KEY' constraint does _not_ specify `CASCADE', the *Note `TRUNCATE TABLE': truncate-table. statement deletes rows one by one and stops if it encounters a parent row that is referenced by the child, returning this error: ERROR 1451 (23000): Cannot delete or update a parent row: a foreign key constraint fails (`test`.`child`, CONSTRAINT `child_ibfk_1` FOREIGN KEY (`parent_id`) REFERENCES `parent` (`id`)) *Note*: In MySQL 5.5 and higher, *Note `TRUNCATE TABLE': truncate-table. is not allowed for `InnoDB' tables referenced by foreign keys. For ease of upgrading, rewrite such statements to use `DELETE' instead. * The `AUTO_INCREMENT' counter is reset to zero by *Note `TRUNCATE TABLE': truncate-table, regardless of whether there is a `FOREIGN KEY' constraint. This is the same as a *Note `DELETE': delete. statement with no `WHERE' clause. The count of rows affected by *Note `TRUNCATE TABLE': truncate-table. is accurate only when it is mapped to a *Note `DELETE': delete. statement. For other storage engines, *Note `TRUNCATE TABLE': truncate-table. differs from *Note `DELETE': delete. in the following ways in MySQL 5.1: * Truncate operations drop and re-create the table, which is much faster than deleting rows one by one, particularly for large tables. * Truncate operations cause an implicit commit. * Truncation operations cannot be performed if the session holds an active table lock. * Truncation operations do not return a meaningful value for the number of deleted rows. The usual result is `0 rows affected,' which should be interpreted as `no information.' * As long as the table format file `TBL_NAME.frm' is valid, the table can be re-created as an empty table with *Note `TRUNCATE TABLE': truncate-table, even if the data or index files have become corrupted. * The table handler does not remember the last used `AUTO_INCREMENT' value, but starts counting from the beginning. This is true even for `MyISAM' and `InnoDB', which normally do not reuse sequence values. * When used with partitioned tables, *Note `TRUNCATE TABLE': truncate-table. preserves the partitioning; that is, the data and index files are dropped and re-created, while the partition definitions (`.par') file is unaffected. * Since truncation of a table does not make any use of *Note `DELETE': delete, the *Note `TRUNCATE TABLE': truncate-table. statement does not invoke `ON DELETE' triggers. As of MySQL 5.1.39, *Note `TRUNCATE TABLE': truncate-table. for a table closes all handlers for the table that were opened with *Note `HANDLER OPEN': handler. Beginning with MySQL 5.1.32, *Note `TRUNCATE TABLE': truncate-table. is treated for purposes of binary logging and replication as *Note `DROP TABLE': drop-table. followed by *Note `CREATE TABLE': create-table.--that is, as DDL rather than DML. This is due to the fact that, when using *Note `InnoDB': innodb-storage-engine. and other transactional storage engines where the transaction isolation level does not permit statement-based logging (`READ COMMITTED' or `READ UNCOMMITTED'), the statement was not logged and replicated when using `STATEMENT' or `MIXED' logging mode. (Bug#36763) However, it is still applied on replication slaves using *Note `InnoDB': innodb-storage-engine. in the manner described previously.  File: manual.info, Node: sql-syntax-data-manipulation, Next: sql-syntax-transactions, Prev: sql-syntax-data-definition, Up: sql-syntax 13.2 Data Manipulation Statements ================================= * Menu: * call:: `CALL' Syntax * delete:: `DELETE' Syntax * do:: `DO' Syntax * handler:: `HANDLER' Syntax * insert:: `INSERT' Syntax * load-data:: `LOAD DATA INFILE' Syntax * replace:: `REPLACE' Syntax * select:: `SELECT' Syntax * subqueries:: Subquery Syntax * update:: `UPDATE' Syntax  File: manual.info, Node: call, Next: delete, Prev: sql-syntax-data-manipulation, Up: sql-syntax-data-manipulation 13.2.1 `CALL' Syntax -------------------- CALL SP_NAME([PARAMETER[,...]]) CALL SP_NAME[()] The *Note `CALL': call. statement invokes a stored procedure that was defined previously with *Note `CREATE PROCEDURE': create-procedure. As of MySQL 5.1.13, stored procedures that take no arguments can be invoked without parentheses. That is, `CALL p()' and `CALL p' are equivalent. *Note `CALL': call. can pass back values to its caller using parameters that are declared as `OUT' or `INOUT' parameters. When the procedure returns, a client program can also obtain the number of rows affected for the final statement executed within the routine: At the SQL level, call the `ROW_COUNT()' function; from the C API, call the *Note `mysql_affected_rows()': mysql-affected-rows. function. To get back a value from a procedure using an `OUT' or `INOUT' parameter, pass the parameter by means of a user variable, and then check the value of the variable after the procedure returns. (If you are calling the procedure from within another stored procedure or function, you can also pass a routine parameter or local routine variable as an `IN' or `INOUT' parameter.) For an `INOUT' parameter, initialize its value before passing it to the procedure. The following procedure has an `OUT' parameter that the procedure sets to the current server version, and an `INOUT' value that the procedure increments by one from its current value: CREATE PROCEDURE p (OUT ver_param VARCHAR(25), INOUT incr_param INT) BEGIN # Set value of OUT parameter SELECT VERSION() INTO ver_param; # Increment value of INOUT parameter SET incr_param = incr_param + 1; END; Before calling the procedure, initialize the variable to be passed as the `INOUT' parameter. After calling the procedure, the values of the two variables will have been set or modified: mysql> SET @increment = 10; mysql> CALL p(@version, @increment); mysql> SELECT @version, @increment; +------------+------------+ | @version | @increment | +------------+------------+ | 5.1.32-log | 11 | +------------+------------+ In prepared *Note `CALL': call. statements used with *Note `PREPARE': prepare. and *Note `EXECUTE': execute, placeholder support is available in MySQL 5.1 for `IN' parameters, but not for `OUT' or `INOUT' parameters. To work around this limitation for `OUT' and `INOUT' parameters, forego the use of placeholders; instead, refer to user variables in the *Note `CALL': call. statement itself and do not specify them in the *Note `EXECUTE': execute. statement: mysql> SET @increment = 10; mysql> PREPARE s FROM 'CALL p(@version, @increment)'; mysql> EXECUTE s; mysql> SELECT @version, @increment; +------------+------------+ | @version | @increment | +------------+------------+ | 5.1.32-log | 11 | +------------+------------+ To write C programs that use the *Note `CALL': call. SQL statement to execute stored procedures that produce result sets, the `CLIENT_MULTI_RESULTS' flag must be enabled. This is because each *Note `CALL': call. returns a result to indicate the call status, in addition to any result sets that might be returned by statements executed within the procedure. `CLIENT_MULTI_RESULTS' must also be enabled if *Note `CALL': call. is used to execute any stored procedure that contains prepared statements. It cannot be determined when such a procedure is loaded whether those statements will produce result sets, so it is necessary to assume that they will. `CLIENT_MULTI_RESULTS' can be enabled when you call *Note `mysql_real_connect()': mysql-real-connect, either explicitly by passing the `CLIENT_MULTI_RESULTS' flag itself, or implicitly by passing `CLIENT_MULTI_STATEMENTS' (which also enables `CLIENT_MULTI_RESULTS'). To process the result of a *Note `CALL': call. statement executed using *Note `mysql_query()': mysql-query. or *Note `mysql_real_query()': mysql-real-query, use a loop that calls *Note `mysql_next_result()': mysql-next-result. to determine whether there are more results. For an example, see *Note c-api-multiple-queries::. For programs written in a language that provides a MySQL interface, there is no native method for directly retrieving the results of `OUT' or `INOUT' parameters from *Note `CALL': call. statements. To get the parameter values, pass user-defined variables to the procedure in the *Note `CALL': call. statement and then execute a *Note `SELECT': select. statement to produce a result set containing the variable values. To handle an `INOUT' parameter, execute a statement prior to the *Note `CALL': call. that sets the corresponding user variable to the value to be passed to the procedure. The following example illustrates the technique (without error checking) for the stored procedure `p' described earlier that has an `OUT' parameter and an `INOUT' parameter: mysql_query(mysql, "SET @increment = 10"); mysql_query(mysql, "CALL p(@version, @increment)"); mysql_query(mysql, "SELECT @version, @increment"); result = mysql_store_result(mysql); row = mysql_fetch_row(result); mysql_free_result(result); After the preceding code executes, `row[0]' and `row[1]' contain the values of `@version' and `@increment', respectively.  File: manual.info, Node: delete, Next: do, Prev: call, Up: sql-syntax-data-manipulation 13.2.2 `DELETE' Syntax ---------------------- Single-table syntax: DELETE [LOW_PRIORITY] [QUICK] [IGNORE] FROM TBL_NAME [WHERE WHERE_CONDITION] [ORDER BY ...] [LIMIT ROW_COUNT] Multiple-table syntax: DELETE [LOW_PRIORITY] [QUICK] [IGNORE] TBL_NAME[.*] [, TBL_NAME[.*]] ... FROM TABLE_REFERENCES [WHERE WHERE_CONDITION] Or: DELETE [LOW_PRIORITY] [QUICK] [IGNORE] FROM TBL_NAME[.*] [, TBL_NAME[.*]] ... USING TABLE_REFERENCES [WHERE WHERE_CONDITION] For the single-table syntax, the *Note `DELETE': delete. statement deletes rows from TBL_NAME and returns a count of the number of deleted rows. This count can be obtained by calling the `ROW_COUNT()' function (see *Note information-functions::). The `WHERE' clause, if given, specifies the conditions that identify which rows to delete. With no `WHERE' clause, all rows are deleted. If the `ORDER BY' clause is specified, the rows are deleted in the order that is specified. The `LIMIT' clause places a limit on the number of rows that can be deleted. For the multiple-table syntax, *Note `DELETE': delete. deletes from each TBL_NAME the rows that satisfy the conditions. In this case, `ORDER BY' and `LIMIT' cannot be used. WHERE_CONDITION is an expression that evaluates to true for each row to be deleted. It is specified as described in *Note select::. Currently, you cannot delete from a table and select from the same table in a subquery. You need the `DELETE' privilege on a table to delete rows from it. You need only the `SELECT' privilege for any columns that are only read, such as those named in the `WHERE' clause. As stated, a *Note `DELETE': delete. statement with no `WHERE' clause deletes all rows. A faster way to do this, when you do not need to know the number of deleted rows, is to use *Note `TRUNCATE TABLE': truncate-table. However, within a transaction or if you have a lock on the table, *Note `TRUNCATE TABLE': truncate-table. cannot be used whereas *Note `DELETE': delete. can. See *Note truncate-table::, and *Note lock-tables::. If you delete the row containing the maximum value for an `AUTO_INCREMENT' column, the value is not reused for a `MyISAM' or `InnoDB' table. If you delete all rows in the table with `DELETE FROM TBL_NAME' (without a `WHERE' clause) in `autocommit' mode, the sequence starts over for all storage engines except `InnoDB' and `MyISAM'. There are some exceptions to this behavior for `InnoDB' tables, as discussed in *Note innodb-auto-increment-handling::. For `MyISAM' tables, you can specify an `AUTO_INCREMENT' secondary column in a multiple-column key. In this case, reuse of values deleted from the top of the sequence occurs even for `MyISAM' tables. See *Note example-auto-increment::. The *Note `DELETE': delete. statement supports the following modifiers: * If you specify `LOW_PRIORITY', the server delays execution of the *Note `DELETE': delete. until no other clients are reading from the table. This affects only storage engines that use only table-level locking (such as `MyISAM', `MEMORY', and `MERGE'). * For `MyISAM' tables, if you use the `QUICK' keyword, the storage engine does not merge index leaves during delete, which may speed up some kinds of delete operations. * The `IGNORE' keyword causes MySQL to ignore all errors during the process of deleting rows. (Errors encountered during the parsing stage are processed in the usual manner.) Errors that are ignored due to the use of `IGNORE' are returned as warnings. The speed of delete operations may also be affected by factors discussed in *Note delete-speed::. In `MyISAM' tables, deleted rows are maintained in a linked list and subsequent *Note `INSERT': insert. operations reuse old row positions. To reclaim unused space and reduce file sizes, use the *Note `OPTIMIZE TABLE': optimize-table. statement or the *Note `myisamchk': myisamchk. utility to reorganize tables. *Note `OPTIMIZE TABLE': optimize-table. is easier to use, but *Note `myisamchk': myisamchk. is faster. See *Note optimize-table::, and *Note myisamchk::. The `QUICK' modifier affects whether index leaves are merged for delete operations. `DELETE QUICK' is most useful for applications where index values for deleted rows are replaced by similar index values from rows inserted later. In this case, the holes left by deleted values are reused. `DELETE QUICK' is not useful when deleted values lead to underfilled index blocks spanning a range of index values for which new inserts occur again. In this case, use of `QUICK' can lead to wasted space in the index that remains unreclaimed. Here is an example of such a scenario: 1. Create a table that contains an indexed `AUTO_INCREMENT' column. 2. Insert many rows into the table. Each insert results in an index value that is added to the high end of the index. 3. Delete a block of rows at the low end of the column range using `DELETE QUICK'. In this scenario, the index blocks associated with the deleted index values become underfilled but are not merged with other index blocks due to the use of `QUICK'. They remain underfilled when new inserts occur, because new rows do not have index values in the deleted range. Furthermore, they remain underfilled even if you later use *Note `DELETE': delete. without `QUICK', unless some of the deleted index values happen to lie in index blocks within or adjacent to the underfilled blocks. To reclaim unused index space under these circumstances, use *Note `OPTIMIZE TABLE': optimize-table. If you are going to delete many rows from a table, it might be faster to use `DELETE QUICK' followed by *Note `OPTIMIZE TABLE': optimize-table. This rebuilds the index rather than performing many index block merge operations. The MySQL-specific `LIMIT ROW_COUNT' option to *Note `DELETE': delete. tells the server the maximum number of rows to be deleted before control is returned to the client. This can be used to ensure that a given *Note `DELETE': delete. statement does not take too much time. You can simply repeat the *Note `DELETE': delete. statement until the number of affected rows is less than the `LIMIT' value. If the *Note `DELETE': delete. statement includes an `ORDER BY' clause, rows are deleted in the order specified by the clause. This is useful primarily in conjunction with `LIMIT'. For example, the following statement finds rows matching the `WHERE' clause, sorts them by `timestamp_column', and deletes the first (oldest) one: DELETE FROM somelog WHERE user = 'jcole' ORDER BY timestamp_column LIMIT 1; `ORDER BY' may also be useful in some cases to delete rows in an order required to avoid referential integrity violations. If you are deleting many rows from a large table, you may exceed the lock table size for an `InnoDB' table. To avoid this problem, or simply to minimize the time that the table remains locked, the following strategy (which does not use *Note `DELETE': delete. at all) might be helpful: 1. Select the rows _not_ to be deleted into an empty table that has the same structure as the original table: INSERT INTO t_copy SELECT * FROM t WHERE ... ; 2. Use *Note `RENAME TABLE': rename-table. to atomically move the original table out of the way and rename the copy to the original name: RENAME TABLE t TO t_old, t_copy TO t; 3. Drop the original table: DROP TABLE t_old; No other sessions can access the tables involved while *Note `RENAME TABLE': rename-table. executes, so the rename operation is not subject to concurrency problems. See *Note rename-table::. You can specify multiple tables in a *Note `DELETE': delete. statement to delete rows from one or more tables depending on the particular condition in the `WHERE' clause. However, you cannot use `ORDER BY' or `LIMIT' in a multiple-table *Note `DELETE': delete. The TABLE_REFERENCES clause lists the tables involved in the join. Its syntax is described in *Note join::. For the first multiple-table syntax, only matching rows from the tables listed before the `FROM' clause are deleted. For the second multiple-table syntax, only matching rows from the tables listed in the `FROM' clause (before the `USING' clause) are deleted. The effect is that you can delete rows from many tables at the same time and have additional tables that are used only for searching: DELETE t1, t2 FROM t1 INNER JOIN t2 INNER JOIN t3 WHERE t1.id=t2.id AND t2.id=t3.id; Or: DELETE FROM t1, t2 USING t1 INNER JOIN t2 INNER JOIN t3 WHERE t1.id=t2.id AND t2.id=t3.id; These statements use all three tables when searching for rows to delete, but delete matching rows only from tables `t1' and `t2'. The preceding examples use `INNER JOIN', but multiple-table *Note `DELETE': delete. statements can use other types of join permitted in *Note `SELECT': select. statements, such as `LEFT JOIN'. For example, to delete rows that exist in `t1' that have no match in `t2', use a `LEFT JOIN': DELETE t1 FROM t1 LEFT JOIN t2 ON t1.id=t2.id WHERE t2.id IS NULL; The syntax permits `.*' after each TBL_NAME for compatibility with `Access'. If you use a multiple-table *Note `DELETE': delete. statement involving `InnoDB' tables for which there are foreign key constraints, the MySQL optimizer might process tables in an order that differs from that of their parent/child relationship. In this case, the statement fails and rolls back. Instead, you should delete from a single table and rely on the `ON DELETE' capabilities that `InnoDB' provides to cause the other tables to be modified accordingly. *Note*: If you declare an alias for a table, you must use the alias when referring to the table: DELETE t1 FROM test AS t1, test2 WHERE ... Table aliases in a multiple-table *Note `DELETE': delete. should be declared only in the TABLE_REFERENCES part of the statement. Correct: DELETE a1, a2 FROM t1 AS a1 INNER JOIN t2 AS a2 WHERE a1.id=a2.id; DELETE FROM a1, a2 USING t1 AS a1 INNER JOIN t2 AS a2 WHERE a1.id=a2.id; Incorrect: DELETE t1 AS a1, t2 AS a2 FROM t1 INNER JOIN t2 WHERE a1.id=a2.id; DELETE FROM t1 AS a1, t2 AS a2 USING t1 INNER JOIN t2 WHERE a1.id=a2.id; Declaration of aliases other than in the TABLE_REFERENCES part of the statement should be avoided because that can lead to ambiguous statements that have unexpected results such as deleting rows from the wrong table. This is such a statement: DELETE t1 AS a2 FROM t1 AS a1 INNER JOIN t2 AS a2; As of MySQL 5.1.23, alias declarations outside the TABLE_REFERENCES part of the statement are disallowed for the `USING' variant of multiple-table *Note `DELETE': delete. syntax. (In MySQL 5.5, alias declarations outside TABLE_REFERENCES are disallowed for all multiple-table *Note `DELETE': delete. statements.) For alias references in the list of tables from which to delete rows in a multiple-table delete, the default database is used unless one is specified explicitly. For example, if the default database is `db1', the following statement does not work because the unqualified alias reference `a2' is interpreted as having a database of `db1': DELETE a1, a2 FROM db1.t1 AS a1 INNER JOIN db2.t2 AS a2 WHERE a1.id=a2.id; To correctly match an alias that refers to a table outside the default database, you must explicitly qualify the reference with the name of the proper database: DELETE a1, db2.a2 FROM db1.t1 AS a1 INNER JOIN db2.t2 AS a2 WHERE a1.id=a2.id;  File: manual.info, Node: do, Next: handler, Prev: delete, Up: sql-syntax-data-manipulation 13.2.3 `DO' Syntax ------------------ DO EXPR [, EXPR] ... *Note `DO': do. executes the expressions but does not return any results. In most respects, *Note `DO': do. is shorthand for `SELECT EXPR, ...', but has the advantage that it is slightly faster when you do not care about the result. *Note `DO': do. is useful primarily with functions that have side effects, such as `RELEASE_LOCK()'.  File: manual.info, Node: handler, Next: insert, Prev: do, Up: sql-syntax-data-manipulation 13.2.4 `HANDLER' Syntax ----------------------- HANDLER TBL_NAME OPEN [ [AS] ALIAS] HANDLER TBL_NAME READ INDEX_NAME { = | <= | >= | < | > } (VALUE1,VALUE2,...) [ WHERE WHERE_CONDITION ] [LIMIT ... ] HANDLER TBL_NAME READ INDEX_NAME { FIRST | NEXT | PREV | LAST } [ WHERE WHERE_CONDITION ] [LIMIT ... ] HANDLER TBL_NAME READ { FIRST | NEXT } [ WHERE WHERE_CONDITION ] [LIMIT ... ] HANDLER TBL_NAME CLOSE The *Note `HANDLER': handler. statement provides direct access to table storage engine interfaces. It is available for `MyISAM' and `InnoDB' tables. The `HANDLER ... OPEN' statement opens a table, making it accessible using subsequent `HANDLER ... READ' statements. This table object is not shared by other sessions and is not closed until the session calls `HANDLER ... CLOSE' or the session terminates. If you open the table using an alias, further references to the open table with other *Note `HANDLER': handler. statements must use the alias rather than the table name. The first `HANDLER ... READ' syntax fetches a row where the index specified satisfies the given values and the `WHERE' condition is met. If you have a multiple-column index, specify the index column values as a comma-separated list. Either specify values for all the columns in the index, or specify values for a leftmost prefix of the index columns. Suppose that an index `my_idx' includes three columns named `col_a', `col_b', and `col_c', in that order. The *Note `HANDLER': handler. statement can specify values for all three columns in the index, or for the columns in a leftmost prefix. For example: HANDLER ... READ my_idx = (col_a_val,col_b_val,col_c_val) ... HANDLER ... READ my_idx = (col_a_val,col_b_val) ... HANDLER ... READ my_idx = (col_a_val) ... To employ the *Note `HANDLER': handler. interface to refer to a table's `PRIMARY KEY', use the quoted identifier ``PRIMARY`': HANDLER TBL_NAME READ `PRIMARY` ... The second `HANDLER ... READ' syntax fetches a row from the table in index order that matches the `WHERE' condition. The third `HANDLER ... READ' syntax fetches a row from the table in natural row order that matches the `WHERE' condition. It is faster than `HANDLER TBL_NAME READ INDEX_NAME' when a full table scan is desired. Natural row order is the order in which rows are stored in a `MyISAM' table data file. This statement works for `InnoDB' tables as well, but there is no such concept because there is no separate data file. Without a `LIMIT' clause, all forms of `HANDLER ... READ' fetch a single row if one is available. To return a specific number of rows, include a `LIMIT' clause. It has the same syntax as for the *Note `SELECT': select. statement. See *Note select::. `HANDLER ... CLOSE' closes a table that was opened with `HANDLER ... OPEN'. There are several reasons to use the *Note `HANDLER': handler. interface instead of normal *Note `SELECT': select. statements: * *Note `HANDLER': handler. is faster than *Note `SELECT': select.: * A designated storage engine handler object is allocated for the `HANDLER ... OPEN'. The object is reused for subsequent *Note `HANDLER': handler. statements for that table; it need not be reinitialized for each one. * There is less parsing involved. * There is no optimizer or query-checking overhead. * The table does not have to be locked between two handler requests. * The handler interface does not have to provide a consistent look of the data (for example, dirty reads are permitted), so the storage engine can use optimizations that *Note `SELECT': select. does not normally permit. * For applications that use a low-level `ISAM'-like interface, *Note `HANDLER': handler. makes it much easier to port them to MySQL. * *Note `HANDLER': handler. enables you to traverse a database in a manner that is difficult (or even impossible) to accomplish with *Note `SELECT': select. The *Note `HANDLER': handler. interface is a more natural way to look at data when working with applications that provide an interactive user interface to the database. *Note `HANDLER': handler. is a somewhat low-level statement. For example, it does not provide consistency. That is, `HANDLER ... OPEN' does _not_ take a snapshot of the table, and does _not_ lock the table. This means that after a `HANDLER ... OPEN' statement is issued, table data can be modified (by the current session or other sessions) and these modifications might be only partially visible to `HANDLER ... NEXT' or `HANDLER ... PREV' scans. An open handler can be closed and marked for reopen, in which case the handler loses its position in the table. This occurs when both of the following circumstances are true: * Any session executes *Note `FLUSH TABLES': flush. or DDL statements on the handler's table. * The session in which the handler is open executes non-*Note `HANDLER': handler. statements that use tables. As of MySQL 5.1.39, *Note `TRUNCATE TABLE': truncate-table. for a table closes all handlers for the table that were opened with *Note `HANDLER OPEN': handler.  File: manual.info, Node: insert, Next: load-data, Prev: handler, Up: sql-syntax-data-manipulation 13.2.5 `INSERT' Syntax ---------------------- * Menu: * insert-select:: `INSERT ... SELECT' Syntax * insert-delayed:: `INSERT DELAYED' Syntax * insert-on-duplicate:: `INSERT ... ON DUPLICATE KEY UPDATE' Syntax INSERT [LOW_PRIORITY | DELAYED | HIGH_PRIORITY] [IGNORE] [INTO] TBL_NAME [(COL_NAME,...)] {VALUES | VALUE} ({EXPR | DEFAULT},...),(...),... [ ON DUPLICATE KEY UPDATE COL_NAME=EXPR [, COL_NAME=EXPR] ... ] Or: INSERT [LOW_PRIORITY | DELAYED | HIGH_PRIORITY] [IGNORE] [INTO] TBL_NAME SET COL_NAME={EXPR | DEFAULT}, ... [ ON DUPLICATE KEY UPDATE COL_NAME=EXPR [, COL_NAME=EXPR] ... ] Or: INSERT [LOW_PRIORITY | HIGH_PRIORITY] [IGNORE] [INTO] TBL_NAME [(COL_NAME,...)] SELECT ... [ ON DUPLICATE KEY UPDATE COL_NAME=EXPR [, COL_NAME=EXPR] ... ] *Note `INSERT': insert. inserts new rows into an existing table. The *Note `INSERT ... VALUES': insert. and *Note `INSERT ... SET': insert. forms of the statement insert rows based on explicitly specified values. The *Note `INSERT ... SELECT': insert-select. form inserts rows selected from another table or tables. *Note `INSERT ... SELECT': insert-select. is discussed further in *Note insert-select::. You can use *Note `REPLACE': replace. instead of *Note `INSERT': insert. to overwrite old rows. *Note `REPLACE': replace. is the counterpart to *Note `INSERT IGNORE': insert. in the treatment of new rows that contain unique key values that duplicate old rows: The new rows are used to replace the old rows rather than being discarded. See *Note replace::. TBL_NAME is the table into which rows should be inserted. The columns for which the statement provides values can be specified as follows: * You can provide a comma-separated list of column names following the table name. In this case, a value for each named column must be provided by the `VALUES' list or the *Note `SELECT': select. statement. * If you do not specify a list of column names for *Note `INSERT ... VALUES': insert. or *Note `INSERT ... SELECT': insert-select, values for every column in the table must be provided by the `VALUES' list or the *Note `SELECT': select. statement. If you do not know the order of the columns in the table, use `DESCRIBE TBL_NAME' to find out. * The `SET' clause indicates the column names explicitly. Column values can be given in several ways: * If you are not running in strict SQL mode, any column not explicitly given a value is set to its default (explicit or implicit) value. For example, if you specify a column list that does not name all the columns in the table, unnamed columns are set to their default values. Default value assignment is described in *Note data-type-defaults::. See also *Note constraint-invalid-data::. If you want an *Note `INSERT': insert. statement to generate an error unless you explicitly specify values for all columns that do not have a default value, you should use strict mode. See *Note server-sql-mode::. * Use the keyword `DEFAULT' to set a column explicitly to its default value. This makes it easier to write *Note `INSERT': insert. statements that assign values to all but a few columns, because it enables you to avoid writing an incomplete `VALUES' list that does not include a value for each column in the table. Otherwise, you would have to write out the list of column names corresponding to each value in the `VALUES' list. You can also use `DEFAULT(COL_NAME)' as a more general form that can be used in expressions to produce a given column's default value. * If both the column list and the `VALUES' list are empty, *Note `INSERT': insert. creates a row with each column set to its default value: INSERT INTO TBL_NAME () VALUES(); In strict mode, an error occurs if any column doesn't have a default value. Otherwise, MySQL uses the implicit default value for any column that does not have an explicitly defined default. * You can specify an expression EXPR to provide a column value. This might involve type conversion if the type of the expression does not match the type of the column, and conversion of a given value can result in different inserted values depending on the data type. For example, inserting the string `'1999.0e-2'' into an *Note `INT': numeric-types, *Note `FLOAT': numeric-types, `DECIMAL(10,6)', or *Note `YEAR': year. column results in the values `1999', `19.9921', `19.992100', and `1999' being inserted, respectively. The reason the value stored in the *Note `INT': numeric-types. and *Note `YEAR': year. columns is `1999' is that the string-to-integer conversion looks only at as much of the initial part of the string as may be considered a valid integer or year. For the floating-point and fixed-point columns, the string-to-floating-point conversion considers the entire string a valid floating-point value. An expression EXPR can refer to any column that was set earlier in a value list. For example, you can do this because the value for `col2' refers to `col1', which has previously been assigned: INSERT INTO TBL_NAME (col1,col2) VALUES(15,col1*2); But the following is not legal, because the value for `col1' refers to `col2', which is assigned after `col1': INSERT INTO TBL_NAME (col1,col2) VALUES(col2*2,15); One exception involves columns that contain `AUTO_INCREMENT' values. Because the `AUTO_INCREMENT' value is generated after other value assignments, any reference to an `AUTO_INCREMENT' column in the assignment returns a `0'. *Note `INSERT': insert. statements that use `VALUES' syntax can insert multiple rows. To do this, include multiple lists of column values, each enclosed within parentheses and separated by commas. Example: INSERT INTO TBL_NAME (a,b,c) VALUES(1,2,3),(4,5,6),(7,8,9); The values list for each row must be enclosed within parentheses. The following statement is illegal because the number of values in the list does not match the number of column names: INSERT INTO TBL_NAME (a,b,c) VALUES(1,2,3,4,5,6,7,8,9); `VALUE' is a synonym for `VALUES' in this context. Neither implies anything about the number of values lists, and either may be used whether there is a single values list or multiple lists. The affected-rows value for an *Note `INSERT': insert. can be obtained using the `ROW_COUNT()' function (see *Note information-functions::), or the *Note `mysql_affected_rows()': mysql-affected-rows. C API function (see *Note mysql-affected-rows::). If you use an *Note `INSERT ... VALUES': insert. statement with multiple value lists or *Note `INSERT ... SELECT': insert-select, the statement returns an information string in this format: Records: 100 Duplicates: 0 Warnings: 0 `Records' indicates the number of rows processed by the statement. (This is not necessarily the number of rows actually inserted because `Duplicates' can be nonzero.) `Duplicates' indicates the number of rows that could not be inserted because they would duplicate some existing unique index value. `Warnings' indicates the number of attempts to insert column values that were problematic in some way. Warnings can occur under any of the following conditions: * Inserting `NULL' into a column that has been declared `NOT NULL'. For multiple-row *Note `INSERT': insert. statements or *Note `INSERT INTO ... SELECT': insert-select. statements, the column is set to the implicit default value for the column data type. This is `0' for numeric types, the empty string (`''') for string types, and the `zero' value for date and time types. *Note `INSERT INTO ... SELECT': insert-select. statements are handled the same way as multiple-row inserts because the server does not examine the result set from the *Note `SELECT': select. to see whether it returns a single row. (For a single-row *Note `INSERT': insert, no warning occurs when `NULL' is inserted into a `NOT NULL' column. Instead, the statement fails with an error.) * Setting a numeric column to a value that lies outside the column's range. The value is clipped to the closest endpoint of the range. * Assigning a value such as `'10.34 a'' to a numeric column. The trailing nonnumeric text is stripped off and the remaining numeric part is inserted. If the string value has no leading numeric part, the column is set to `0'. * Inserting a string into a string column (*Note `CHAR': char, *Note `VARCHAR': char, *Note `TEXT': blob, or *Note `BLOB': blob.) that exceeds the column's maximum length. The value is truncated to the column's maximum length. * Inserting a value into a date or time column that is illegal for the data type. The column is set to the appropriate zero value for the type. If you are using the C API, the information string can be obtained by invoking the *Note `mysql_info()': mysql-info. function. See *Note mysql-info::. If *Note `INSERT': insert. inserts a row into a table that has an `AUTO_INCREMENT' column, you can find the value used for that column by using the SQL `LAST_INSERT_ID()' function. From within the C API, use the *Note `mysql_insert_id()': mysql-insert-id. function. However, you should note that the two functions do not always behave identically. The behavior of *Note `INSERT': insert. statements with respect to `AUTO_INCREMENT' columns is discussed further in *Note information-functions::, and *Note mysql-insert-id::. The *Note `INSERT': insert. statement supports the following modifiers: * If you use the `DELAYED' keyword, the server puts the row or rows to be inserted into a buffer, and the client issuing the *Note `INSERT DELAYED': insert-delayed. statement can then continue immediately. If the table is in use, the server holds the rows. When the table is free, the server begins inserting rows, checking periodically to see whether there are any new read requests for the table. If there are, the delayed row queue is suspended until the table becomes free again. See *Note insert-delayed::. `DELAYED' is ignored with *Note `INSERT ... SELECT': insert-select. or *Note `INSERT ... ON DUPLICATE KEY UPDATE': insert-on-duplicate. Beginning with MySQL 5.1.19, `DELAYED' is also disregarded for an *Note `INSERT': insert. that uses functions accessing tables or triggers, or that is called from a function or a trigger. * If you use the `LOW_PRIORITY' keyword, execution of the *Note `INSERT': insert. is delayed until no other clients are reading from the table. This includes other clients that began reading while existing clients are reading, and while the `INSERT LOW_PRIORITY' statement is waiting. It is possible, therefore, for a client that issues an `INSERT LOW_PRIORITY' statement to wait for a very long time (or even forever) in a read-heavy environment. (This is in contrast to *Note `INSERT DELAYED': insert-delayed, which lets the client continue at once. Note that `LOW_PRIORITY' should normally not be used with `MyISAM' tables because doing so disables concurrent inserts. See *Note concurrent-inserts::. If you specify `HIGH_PRIORITY', it overrides the effect of the `--low-priority-updates' option if the server was started with that option. It also causes concurrent inserts not to be used. See *Note concurrent-inserts::. `LOW_PRIORITY' and `HIGH_PRIORITY' affect only storage engines that use only table-level locking (such as `MyISAM', `MEMORY', and `MERGE'). * If you use the `IGNORE' keyword, errors that occur while executing the *Note `INSERT': insert. statement are treated as warnings instead. For example, without `IGNORE', a row that duplicates an existing `UNIQUE' index or `PRIMARY KEY' value in the table causes a duplicate-key error and the statement is aborted. With `IGNORE', the row still is not inserted, but no error is issued. `IGNORE' has a similar effect on inserts into partitioned tables where no partition matching a given value is found. Without `IGNORE', such *Note `INSERT': insert. statements are aborted with an error; however, when *Note `INSERT IGNORE': insert. is used, the insert operation fails silently for the row containing the unmatched value, but any rows that are matched are inserted. For an example, see *Note partitioning-list::. Data conversions that would trigger errors abort the statement if `IGNORE' is not specified. With `IGNORE', invalid values are adjusted to the closest values and inserted; warnings are produced but the statement does not abort. You can determine with the *Note `mysql_info()': mysql-info. C API function how many rows were actually inserted into the table. * If you specify `ON DUPLICATE KEY UPDATE', and a row is inserted that would cause a duplicate value in a `UNIQUE' index or `PRIMARY KEY', an *Note `UPDATE': update. of the old row is performed. The affected-rows value per row is 1 if the row is inserted as a new row and 2 if an existing row is updated. See *Note insert-on-duplicate::. Inserting into a table requires the `INSERT' privilege for the table. If the `ON DUPLICATE KEY UPDATE' clause is used and a duplicate key causes an *Note `UPDATE': update. to be performed instead, the statement requires the `UPDATE' privilege for the columns to be updated. For columns that are read but not modified you need only the `SELECT' privilege (such as for a column referenced only on the right hand side of an COL_NAME=EXPR assignment in an `ON DUPLICATE KEY UPDATE' clause).  File: manual.info, Node: insert-select, Next: insert-delayed, Prev: insert, Up: insert 13.2.5.1 `INSERT ... SELECT' Syntax ................................... INSERT [LOW_PRIORITY | HIGH_PRIORITY] [IGNORE] [INTO] TBL_NAME [(COL_NAME,...)] SELECT ... [ ON DUPLICATE KEY UPDATE COL_NAME=EXPR, ... ] With *Note `INSERT ... SELECT': insert-select, you can quickly insert many rows into a table from one or many tables. For example: INSERT INTO tbl_temp2 (fld_id) SELECT tbl_temp1.fld_order_id FROM tbl_temp1 WHERE tbl_temp1.fld_order_id > 100; The following conditions hold for a *Note `INSERT ... SELECT': insert-select. statements: * Specify `IGNORE' to ignore rows that would cause duplicate-key violations. * `DELAYED' is ignored with *Note `INSERT ... SELECT': insert-select. * The target table of the *Note `INSERT': insert. statement may appear in the `FROM' clause of the *Note `SELECT': select. part of the query. (This was not possible in some older versions of MySQL.) However, you cannot insert into a table and select from the same table in a subquery. When selecting from and inserting into a table at the same time, MySQL creates a temporary table to hold the rows from the *Note `SELECT': select. and then inserts those rows into the target table. However, it remains true that you cannot use `INSERT INTO t ... SELECT ... FROM t' when `t' is a `TEMPORARY' table, because `TEMPORARY' tables cannot be referred to twice in the same statement (see *Note temporary-table-problems::). * `AUTO_INCREMENT' columns work as usual. * To ensure that the binary log can be used to re-create the original tables, MySQL does not permit concurrent inserts for *Note `INSERT ... SELECT': insert-select. statements. * To avoid ambiguous column reference problems when the *Note `SELECT': select. and the *Note `INSERT': insert. refer to the same table, provide a unique alias for each table used in the *Note `SELECT': select. part, and qualify column names in that part with the appropriate alias. In the values part of `ON DUPLICATE KEY UPDATE', you can refer to columns in other tables, as long as you do not use `GROUP BY' in the *Note `SELECT': select. part. One side effect is that you must qualify nonunique column names in the values part. The order in which rows are returned by a *Note `SELECT': select. statement with no `ORDER BY' clause is not determined. This means that, when using replication, there is no guarantee that such a `SELECT' returns rows in the same order on the master and the slave; this can lead to inconsistencies between them. To prevent this from occurring, you should always write `INSERT ... SELECT' statements that are to be replicated as `INSERT ... SELECT ... ORDER BY COLUMN'. The choice of COLUMN does not matter as long as the same order for returning the rows is enforced on both the master and the slave. See also *Note replication-features-limit::.  File: manual.info, Node: insert-delayed, Next: insert-on-duplicate, Prev: insert-select, Up: insert 13.2.5.2 `INSERT DELAYED' Syntax ................................ INSERT DELAYED ... The `DELAYED' option for the *Note `INSERT': insert. statement is a MySQL extension to standard SQL that is very useful if you have clients that cannot or need not wait for the *Note `INSERT': insert. to complete. This is a common situation when you use MySQL for logging and you also periodically run *Note `SELECT': select. and *Note `UPDATE': update. statements that take a long time to complete. When a client uses *Note `INSERT DELAYED': insert-delayed, it gets an okay from the server at once, and the row is queued to be inserted when the table is not in use by any other thread. Another major benefit of using *Note `INSERT DELAYED': insert-delayed. is that inserts from many clients are bundled together and written in one block. This is much faster than performing many separate inserts. Note that *Note `INSERT DELAYED': insert-delayed. is slower than a normal *Note `INSERT': insert. if the table is not otherwise in use. There is also the additional overhead for the server to handle a separate thread for each table for which there are delayed rows. This means that you should use *Note `INSERT DELAYED': insert-delayed. only when you are really sure that you need it. The queued rows are held only in memory until they are inserted into the table. This means that if you terminate *Note `mysqld': mysqld. forcibly (for example, with `kill -9') or if *Note `mysqld': mysqld. dies unexpectedly, _any queued rows that have not been written to disk are lost_. There are some constraints on the use of `DELAYED': * *Note `INSERT DELAYED': insert-delayed. works only with `MyISAM', `MEMORY', `ARCHIVE', and (as of MySQL 5.1.19) `BLACKHOLE' tables. For engines that do not support `DELAYED', an error occurs. * An error occurs for *Note `INSERT DELAYED': insert-delayed. if used with a table that has been locked with `LOCK TABLES' because the insert must be handled by a separate thread, not by the session that holds the lock. * For `MyISAM' tables, if there are no free blocks in the middle of the data file, concurrent *Note `SELECT': select. and *Note `INSERT': insert. statements are supported. Under these circumstances, you very seldom need to use *Note `INSERT DELAYED': insert-delayed. with `MyISAM'. * *Note `INSERT DELAYED': insert-delayed. should be used only for *Note `INSERT': insert. statements that specify value lists. The server ignores `DELAYED' for *Note `INSERT ... SELECT': insert-select. or *Note `INSERT ... ON DUPLICATE KEY UPDATE': insert-on-duplicate. statements. * Because the *Note `INSERT DELAYED': insert-delayed. statement returns immediately, before the rows are inserted, you cannot use `LAST_INSERT_ID()' to get the `AUTO_INCREMENT' value that the statement might generate. * `DELAYED' rows are not visible to *Note `SELECT': select. statements until they actually have been inserted. * *Note `INSERT DELAYED': insert-delayed. is treated as a normal *Note `INSERT': insert. if the statement inserts multiple rows and binary logging is enabled and the global logging format is to use statement-based logging (`binlog_format' is set to `STATEMENT'). This restriction does not apply to row-based binary logging. * `DELAYED' is ignored on slave replication servers, so that *Note `INSERT DELAYED': insert-delayed. is treated as a normal *Note `INSERT': insert. on slaves. This is because `DELAYED' could cause the slave to have different data than the master. * Pending *Note `INSERT DELAYED': insert-delayed. statements are lost if a table is write locked and *Note `ALTER TABLE': alter-table. is used to modify the table structure. * *Note `INSERT DELAYED': insert-delayed. is not supported for views. * *Note `INSERT DELAYED': insert-delayed. is not supported for partitioned tables. The following describes in detail what happens when you use the `DELAYED' option to *Note `INSERT': insert. or *Note `REPLACE': replace. In this description, the `thread' is the thread that received an *Note `INSERT DELAYED': insert-delayed. statement and `handler' is the thread that handles all *Note `INSERT DELAYED': insert-delayed. statements for a particular table. * When a thread executes a `DELAYED' statement for a table, a handler thread is created to process all `DELAYED' statements for the table, if no such handler already exists. * The thread checks whether the handler has previously acquired a `DELAYED' lock; if not, it tells the handler thread to do so. The `DELAYED' lock can be obtained even if other threads have a `READ' or `WRITE' lock on the table. However, the handler waits for all *Note `ALTER TABLE': alter-table. locks or *Note `FLUSH TABLES': flush. statements to finish, to ensure that the table structure is up to date. * The thread executes the *Note `INSERT': insert. statement, but instead of writing the row to the table, it puts a copy of the final row into a queue that is managed by the handler thread. Any syntax errors are noticed by the thread and reported to the client program. * The client cannot obtain from the server the number of duplicate rows or the `AUTO_INCREMENT' value for the resulting row, because the *Note `INSERT': insert. returns before the insert operation has been completed. (If you use the C API, the *Note `mysql_info()': mysql-info. function does not return anything meaningful, for the same reason.) * The binary log is updated by the handler thread when the row is inserted into the table. In case of multiple-row inserts, the binary log is updated when the first row is inserted. * Each time that `delayed_insert_limit' rows are written, the handler checks whether any *Note `SELECT': select. statements are still pending. If so, it permits these to execute before continuing. * When the handler has no more rows in its queue, the table is unlocked. If no new *Note `INSERT DELAYED': insert-delayed. statements are received within `delayed_insert_timeout' seconds, the handler terminates. * If more than `delayed_queue_size' rows are pending in a specific handler queue, the thread requesting *Note `INSERT DELAYED': insert-delayed. waits until there is room in the queue. This is done to ensure that *Note `mysqld': mysqld. does not use all memory for the delayed memory queue. * The handler thread shows up in the MySQL process list with `delayed_insert' in the `Command' column. It is killed if you execute a *Note `FLUSH TABLES': flush. statement or kill it with `KILL THREAD_ID'. However, before exiting, it first stores all queued rows into the table. During this time it does not accept any new *Note `INSERT': insert. statements from other threads. If you execute an *Note `INSERT DELAYED': insert-delayed. statement after this, a new handler thread is created. Note that this means that *Note `INSERT DELAYED': insert-delayed. statements have higher priority than normal *Note `INSERT': insert. statements if there is an *Note `INSERT DELAYED': insert-delayed. handler running. Other update statements have to wait until the *Note `INSERT DELAYED': insert-delayed. queue is empty, someone terminates the handler thread (with `KILL THREAD_ID'), or someone executes a *Note `FLUSH TABLES': flush. * The following status variables provide information about *Note `INSERT DELAYED': insert-delayed. statements. Status Variable Meaning `Delayed_insert_threads' Number of handler threads `Delayed_writes' Number of rows written with *Note `INSERT DELAYED': insert-delayed. `Not_flushed_delayed_rows' Number of rows waiting to be written You can view these variables by issuing a *Note `SHOW STATUS': show-status. statement or by executing a *Note `mysqladmin extended-status': mysqladmin. command.  File: manual.info, Node: insert-on-duplicate, Prev: insert-delayed, Up: insert 13.2.5.3 `INSERT ... ON DUPLICATE KEY UPDATE' Syntax .................................................... If you specify `ON DUPLICATE KEY UPDATE', and a row is inserted that would cause a duplicate value in a `UNIQUE' index or `PRIMARY KEY', an *Note `UPDATE': update. of the old row is performed. For example, if column `a' is declared as `UNIQUE' and contains the value `1', the following two statements have identical effect: INSERT INTO table (a,b,c) VALUES (1,2,3) ON DUPLICATE KEY UPDATE c=c+1; UPDATE table SET c=c+1 WHERE a=1; With `ON DUPLICATE KEY UPDATE', the affected-rows value per row is 1 if the row is inserted as a new row and 2 if an existing row is updated. If column `b' is also unique, the *Note `INSERT': insert. is equivalent to this *Note `UPDATE': update. statement instead: UPDATE table SET c=c+1 WHERE a=1 OR b=2 LIMIT 1; If `a=1 OR b=2' matches several rows, only _one_ row is updated. In general, you should try to avoid using an `ON DUPLICATE KEY UPDATE' clause on tables with multiple unique indexes. The `ON DUPLICATE KEY UPDATE' clause can contain multiple column assignments, separated by commas. You can use the `VALUES(COL_NAME)' function in the *Note `UPDATE': update. clause to refer to column values from the *Note `INSERT': insert. portion of the *Note `INSERT ... ON DUPLICATE KEY UPDATE': insert-on-duplicate. statement. In other words, `VALUES(COL_NAME)' in the `ON DUPLICATE KEY UPDATE' clause refers to the value of COL_NAME that would be inserted, had no duplicate-key conflict occurred. This function is especially useful in multiple-row inserts. The `VALUES()' function is meaningful only in `INSERT ... UPDATE' statements and returns `NULL' otherwise. Example: INSERT INTO table (a,b,c) VALUES (1,2,3),(4,5,6) ON DUPLICATE KEY UPDATE c=VALUES(a)+VALUES(b); That statement is identical to the following two statements: INSERT INTO table (a,b,c) VALUES (1,2,3) ON DUPLICATE KEY UPDATE c=3; INSERT INTO table (a,b,c) VALUES (4,5,6) ON DUPLICATE KEY UPDATE c=9; If a table contains an `AUTO_INCREMENT' column and *Note `INSERT ... ON DUPLICATE KEY UPDATE': insert-on-duplicate. inserts a row, the `LAST_INSERT_ID()' function returns the `AUTO_INCREMENT' value. If the statement updates a row instead, `LAST_INSERT_ID()' is not meaningful prior to MySQL 5.1.12. However, you can work around this by using `LAST_INSERT_ID(EXPR)'. Suppose that `id' is the `AUTO_INCREMENT' column. To make `LAST_INSERT_ID()' meaningful for updates, insert rows as follows: INSERT INTO table (a,b,c) VALUES (1,2,3) ON DUPLICATE KEY UPDATE id=LAST_INSERT_ID(id), c=3; The `DELAYED' option is ignored when you use `ON DUPLICATE KEY UPDATE'.  File: manual.info, Node: load-data, Next: replace, Prev: insert, Up: sql-syntax-data-manipulation 13.2.6 `LOAD DATA INFILE' Syntax -------------------------------- LOAD DATA [LOW_PRIORITY | CONCURRENT] [LOCAL] INFILE 'FILE_NAME' [REPLACE | IGNORE] INTO TABLE TBL_NAME [CHARACTER SET CHARSET_NAME] [{FIELDS | COLUMNS} [TERMINATED BY 'STRING'] [[OPTIONALLY] ENCLOSED BY 'CHAR'] [ESCAPED BY 'CHAR'] ] [LINES [STARTING BY 'STRING'] [TERMINATED BY 'STRING'] ] [IGNORE NUMBER LINES] [(COL_NAME_OR_USER_VAR,...)] [SET COL_NAME = EXPR,...] The *Note `LOAD DATA INFILE': load-data. statement reads rows from a text file into a table at a very high speed. The file name must be given as a literal string. *Note `LOAD DATA INFILE': load-data. is the complement of *Note `SELECT ... INTO OUTFILE': select. (See *Note select::.) To write data from a table to a file, use *Note `SELECT ... INTO OUTFILE': select. To read the file back into a table, use *Note `LOAD DATA INFILE': load-data. The syntax of the `FIELDS' and `LINES' clauses is the same for both statements. Both clauses are optional, but `FIELDS' must precede `LINES' if both are specified. For more information about the efficiency of *Note `INSERT': insert. versus *Note `LOAD DATA INFILE': load-data. and speeding up *Note `LOAD DATA INFILE': load-data, see *Note insert-speed::. The character set indicated by the `character_set_database' system variable is used to interpret the information in the file. `SET NAMES' and the setting of `character_set_client' do not affect interpretation of input. If the contents of the input file use a character set that differs from the default, it is usually preferable to specify the character set of the file by using the `CHARACTER SET' clause, which is available as of MySQL 5.1.17. A character set of `binary' specifies `no conversion.' *Note `LOAD DATA INFILE': load-data. interprets all fields in the file as having the same character set, regardless of the data types of the columns into which field values are loaded. For proper interpretation of file contents, you must ensure that it was written with the correct character set. For example, if you write a data file with *Note `mysqldump -T': mysqldump. or by issuing a *Note `SELECT ... INTO OUTFILE': select. statement in *Note `mysql': mysql, be sure to use a `--default-character-set' option with *Note `mysqldump': mysqldump. or *Note `mysql': mysql. so that output is written in the character set to be used when the file is loaded with *Note `LOAD DATA INFILE': load-data. *Note*: It is not possible to load data files that use the `ucs2' character set. As of MySQL 5.1.6, the `character_set_filesystem' system variable controls the interpretation of the file name. You can also load data files by using the *Note `mysqlimport': mysqlimport. utility; it operates by sending a *Note `LOAD DATA INFILE': load-data. statement to the server. The `--local' option causes *Note `mysqlimport': mysqlimport. to read data files from the client host. You can specify the `--compress' option to get better performance over slow networks if the client and server support the compressed protocol. See *Note mysqlimport::. If you use `LOW_PRIORITY', execution of the *Note `LOAD DATA': load-data. statement is delayed until no other clients are reading from the table. This affects only storage engines that use only table-level locking (such as `MyISAM', `MEMORY', and `MERGE'). If you specify `CONCURRENT' with a `MyISAM' table that satisfies the condition for concurrent inserts (that is, it contains no free blocks in the middle), other threads can retrieve data from the table while *Note `LOAD DATA': load-data. is executing. Using this option affects the performance of *Note `LOAD DATA': load-data. a bit, even if no other thread is using the table at the same time. Prior to MySQL 5.1.43, `CONCURRENT' was not replicated when using statement-based replication (see Bug#34628). However, it is replicated when using row-based replication, regardless of the version. See *Note replication-features-load-data::, for more information. *Note*: Prior to MySQL 5.1.23, *Note `LOAD DATA': load-data. performed very poorly when importing into partitioned tables. The statement now uses buffering to improve performance; however, the buffer uses 130KB memory per partition to achieve this. (Bug#26527) The `LOCAL' keyword, if specified, is interpreted with respect to the client end of the connection: * If `LOCAL' is specified, the file is read by the client program on the client host and sent to the server. The file can be given as a full path name to specify its exact location. If given as a relative path name, the name is interpreted relative to the directory in which the client program was started. * If `LOCAL' is not specified, the file must be located on the server host and is read directly by the server. The server uses the following rules to locate the file: * If the file name is an absolute path name, the server uses it as given. * If the file name is a relative path name with one or more leading components, the server searches for the file relative to the server's data directory. * If a file name with no leading components is given, the server looks for the file in the database directory of the default database. Note that, in the non-`LOCAL' case, these rules mean that a file named as `./myfile.txt' is read from the server's data directory, whereas the file named as `myfile.txt' is read from the database directory of the default database. For example, if `db1' is the default database, the following *Note `LOAD DATA': load-data. statement reads the file `data.txt' from the database directory for `db1', even though the statement explicitly loads the file into a table in the `db2' database: LOAD DATA INFILE 'data.txt' INTO TABLE db2.my_table; Windows path names are specified using forward slashes rather than backslashes. If you do use backslashes, you must double them. *Note*: A regression in MySQL 5.1.40 caused the database referenced in a fully qualified table name to be ignored by *Note `LOAD DATA': load-data. when using replication with either `STATEMENT' or `MIXED' as the binary logging format; this could lead to problems if the table was not in the current database. As a workaround, you can specify the correct database with the *Note `USE': use. statement prior to executing *Note `LOAD DATA': load-data. If necessary, you can reset the default database with a second *Note `USE': use. statement following the *Note `LOAD DATA': load-data. statement. This issue was fixed in MySQL 5.1.41. (Bug#48297) For security reasons, when reading text files located on the server, the files must either reside in the database directory or be readable by all. Also, to use *Note `LOAD DATA INFILE': load-data. on server files, you must have the `FILE' privilege. See *Note privileges-provided::. For non-`LOCAL' load operations, if the `secure_file_priv' system variable is set to a nonempty directory name, the file to be loaded must be located in that directory. Using `LOCAL' is a bit slower than letting the server access the files directly, because the contents of the file must be sent over the connection by the client to the server. On the other hand, you do not need the `FILE' privilege to load local files. With `LOCAL', the default duplicate-key handling behavior is the same as if `IGNORE' is specified; this is because the server has no way to stop transmission of the file in the middle of the operation. `IGNORE' is explained further later in this section. `LOCAL' works only if your server and your client both have been configured to permit it. For example, if *Note `mysqld': mysqld. was started with `--local-infile=0', `LOCAL' does not work. See *Note load-data-local::. On Unix, if you need *Note `LOAD DATA': load-data. to read from a pipe, you can use the following technique (the example loads a listing of the `/' directory into the table `db1.t1'): mkfifo /mysql/data/db1/ls.dat chmod 666 /mysql/data/db1/ls.dat find / -ls > /mysql/data/db1/ls.dat & mysql -e "LOAD DATA INFILE 'ls.dat' INTO TABLE t1" db1 Note that you must run the command that generates the data to be loaded and the *Note `mysql': mysql. commands either on separate terminals, or run the data generation process in the background (as shown in the preceding example). If you do not do this, the pipe will block until data is read by the *Note `mysql': mysql. process. The *Note `REPLACE': replace. and `IGNORE' keywords control handling of input rows that duplicate existing rows on unique key values: * If you specify *Note `REPLACE': replace, input rows replace existing rows. In other words, rows that have the same value for a primary key or unique index as an existing row. See *Note replace::. * If you specify `IGNORE', input rows that duplicate an existing row on a unique key value are skipped. If you do not specify either option, the behavior depends on whether the `LOCAL' keyword is specified. Without `LOCAL', an error occurs when a duplicate key value is found, and the rest of the text file is ignored. With `LOCAL', the default behavior is the same as if `IGNORE' is specified; this is because the server has no way to stop transmission of the file in the middle of the operation. If you want to ignore foreign key constraints during the load operation, you can issue a `SET foreign_key_checks = 0' statement before executing *Note `LOAD DATA': load-data. If you use *Note `LOAD DATA INFILE': load-data. on an empty `MyISAM' table, all nonunique indexes are created in a separate batch (as for *Note `REPAIR TABLE': repair-table.). Normally, this makes *Note `LOAD DATA INFILE': load-data. much faster when you have many indexes. In some extreme cases, you can create the indexes even faster by turning them off with `ALTER TABLE ... DISABLE KEYS' before loading the file into the table and using `ALTER TABLE ... ENABLE KEYS' to re-create the indexes after loading the file. See *Note insert-speed::. For both the *Note `LOAD DATA INFILE': load-data. and *Note `SELECT ... INTO OUTFILE': select. statements, the syntax of the `FIELDS' and `LINES' clauses is the same. Both clauses are optional, but `FIELDS' must precede `LINES' if both are specified. If you specify a `FIELDS' clause, each of its subclauses (`TERMINATED BY', `[OPTIONALLY] ENCLOSED BY', and `ESCAPED BY') is also optional, except that you must specify at least one of them. If you specify no `FIELDS' or `LINES' clause, the defaults are the same as if you had written this: FIELDS TERMINATED BY '\t' ENCLOSED BY '' ESCAPED BY '\\' LINES TERMINATED BY '\n' STARTING BY '' (Backslash is the MySQL escape character within strings in SQL statements, so to specify a literal backslash, you must specify two backslashes for the value to be interpreted as a single backslash. The escape sequences `'\t'' and `'\n'' specify tab and newline characters, respectively.) In other words, the defaults cause *Note `LOAD DATA INFILE': load-data. to act as follows when reading input: * Look for line boundaries at newlines. * Do not skip over any line prefix. * Break lines into fields at tabs. * Do not expect fields to be enclosed within any quoting characters. * Interpret characters preceded by the escape character ``\'' as escape sequences. For example, ``\t'', ``\n'', and ``\\'' signify tab, newline, and backslash, respectively. See the discussion of `FIELDS ESCAPED BY' later for the full list of escape sequences. Conversely, the defaults cause *Note `SELECT ... INTO OUTFILE': select. to act as follows when writing output: * Write tabs between fields. * Do not enclose fields within any quoting characters. * Use ``\'' to escape instances of tab, newline, or ``\'' that occur within field values. * Write newlines at the ends of lines. *Note*: If you have generated the text file on a Windows system, you might have to use `LINES TERMINATED BY '\r\n'' to read the file properly, because Windows programs typically use two characters as a line terminator. Some programs, such as `WordPad', might use `\r' as a line terminator when writing files. To read such files, use `LINES TERMINATED BY '\r''. If all the lines you want to read in have a common prefix that you want to ignore, you can use `LINES STARTING BY 'PREFIX_STRING'' to skip over the prefix, _and anything before it_. If a line does not include the prefix, the entire line is skipped. Suppose that you issue the following statement: LOAD DATA INFILE '/tmp/test.txt' INTO TABLE test FIELDS TERMINATED BY ',' LINES STARTING BY 'xxx'; If the data file looks like this: xxx"abc",1 something xxx"def",2 "ghi",3 The resulting rows will be `("abc",1)' and `("def",2)'. The third row in the file is skipped because it does not contain the prefix. The `IGNORE NUMBER LINES' option can be used to ignore lines at the start of the file. For example, you can use `IGNORE 1 LINES' to skip over an initial header line containing column names: LOAD DATA INFILE '/tmp/test.txt' INTO TABLE test IGNORE 1 LINES; When you use *Note `SELECT ... INTO OUTFILE': select. in tandem with *Note `LOAD DATA INFILE': load-data. to write data from a database into a file and then read the file back into the database later, the field- and line-handling options for both statements must match. Otherwise, *Note `LOAD DATA INFILE': load-data. will not interpret the contents of the file properly. Suppose that you use *Note `SELECT ... INTO OUTFILE': select. to write a file with fields delimited by commas: SELECT * INTO OUTFILE 'data.txt' FIELDS TERMINATED BY ',' FROM table2; To read the comma-delimited file back in, the correct statement would be: LOAD DATA INFILE 'data.txt' INTO TABLE table2 FIELDS TERMINATED BY ','; If instead you tried to read in the file with the statement shown following, it wouldn't work because it instructs *Note `LOAD DATA INFILE': load-data. to look for tabs between fields: LOAD DATA INFILE 'data.txt' INTO TABLE table2 FIELDS TERMINATED BY '\t'; The likely result is that each input line would be interpreted as a single field. *Note `LOAD DATA INFILE': load-data. can be used to read files obtained from external sources. For example, many programs can export data in comma-separated values (CSV) format, such that lines have fields separated by commas and enclosed within double quotation marks, with an initial line of column names. If the lines in such a file are terminated by carriage return/newline pairs, the statement shown here illustrates the field- and line-handling options you would use to load the file: LOAD DATA INFILE 'data.txt' INTO TABLE TBL_NAME FIELDS TERMINATED BY ',' ENCLOSED BY '"' LINES TERMINATED BY '\r\n' IGNORE 1 LINES; If the input values are not necessarily enclosed within quotation marks, use `OPTIONALLY' before the `ENCLOSED BY' keywords. Any of the field- or line-handling options can specify an empty string (`'''). If not empty, the `FIELDS [OPTIONALLY] ENCLOSED BY' and `FIELDS ESCAPED BY' values must be a single character. The `FIELDS TERMINATED BY', `LINES STARTING BY', and `LINES TERMINATED BY' values can be more than one character. For example, to write lines that are terminated by carriage return/linefeed pairs, or to read a file containing such lines, specify a `LINES TERMINATED BY '\r\n'' clause. To read a file containing jokes that are separated by lines consisting of `%%', you can do this CREATE TABLE jokes (a INT NOT NULL AUTO_INCREMENT PRIMARY KEY, joke TEXT NOT NULL); LOAD DATA INFILE '/tmp/jokes.txt' INTO TABLE jokes FIELDS TERMINATED BY '' LINES TERMINATED BY '\n%%\n' (joke); `FIELDS [OPTIONALLY] ENCLOSED BY' controls quoting of fields. For output (*Note `SELECT ... INTO OUTFILE': select.), if you omit the word `OPTIONALLY', all fields are enclosed by the `ENCLOSED BY' character. An example of such output (using a comma as the field delimiter) is shown here: "1","a string","100.20" "2","a string containing a , comma","102.20" "3","a string containing a \" quote","102.20" "4","a string containing a \", quote and comma","102.20" If you specify `OPTIONALLY', the `ENCLOSED BY' character is used only to enclose values from columns that have a string data type (such as *Note `CHAR': char, *Note `BINARY': binary-varbinary, *Note `TEXT': blob, or *Note `ENUM': enum.): 1,"a string",100.20 2,"a string containing a , comma",102.20 3,"a string containing a \" quote",102.20 4,"a string containing a \", quote and comma",102.20 Note that occurrences of the `ENCLOSED BY' character within a field value are escaped by prefixing them with the `ESCAPED BY' character. Also note that if you specify an empty `ESCAPED BY' value, it is possible to inadvertently generate output that cannot be read properly by *Note `LOAD DATA INFILE': load-data. For example, the preceding output just shown would appear as follows if the escape character is empty. Observe that the second field in the fourth line contains a comma following the quote, which (erroneously) appears to terminate the field: 1,"a string",100.20 2,"a string containing a , comma",102.20 3,"a string containing a " quote",102.20 4,"a string containing a ", quote and comma",102.20 For input, the `ENCLOSED BY' character, if present, is stripped from the ends of field values. (This is true regardless of whether `OPTIONALLY' is specified; `OPTIONALLY' has no effect on input interpretation.) Occurrences of the `ENCLOSED BY' character preceded by the `ESCAPED BY' character are interpreted as part of the current field value. If the field begins with the `ENCLOSED BY' character, instances of that character are recognized as terminating a field value only if followed by the field or line `TERMINATED BY' sequence. To avoid ambiguity, occurrences of the `ENCLOSED BY' character within a field value can be doubled and are interpreted as a single instance of the character. For example, if `ENCLOSED BY '"'' is specified, quotation marks are handled as shown here: "The ""BIG"" boss" -> The "BIG" boss The "BIG" boss -> The "BIG" boss The ""BIG"" boss -> The ""BIG"" boss `FIELDS ESCAPED BY' controls how to read or write special characters: * For input, if the `FIELDS ESCAPED BY' character is not empty, occurrences of that character are stripped and the following character is taken literally as part of a field value. Some two-character sequences that are exceptions, where the first character is the escape character. These sequences are shown in the following table (using ``\'' for the escape character). The rules for `NULL' handling are described later in this section. Character Escape Sequence `\0' An ASCII NUL (`0x00') character `\b' A backspace character `\n' A newline (linefeed) character `\r' A carriage return character `\t' A tab character. `\Z' ASCII 26 (Control+Z) `\N' NULL For more information about ``\''-escape syntax, see *Note string-syntax::. If the `FIELDS ESCAPED BY' character is empty, escape-sequence interpretation does not occur. * For output, if the `FIELDS ESCAPED BY' character is not empty, it is used to prefix the following characters on output: * The `FIELDS ESCAPED BY' character * The `FIELDS [OPTIONALLY] ENCLOSED BY' character * The first character of the `FIELDS TERMINATED BY' and `LINES TERMINATED BY' values * ASCII `0' (what is actually written following the escape character is ASCII ``0'', not a zero-valued byte) If the `FIELDS ESCAPED BY' character is empty, no characters are escaped and `NULL' is output as `NULL', not `\N'. It is probably not a good idea to specify an empty escape character, particularly if field values in your data contain any of the characters in the list just given. In certain cases, field- and line-handling options interact: * If `LINES TERMINATED BY' is an empty string and `FIELDS TERMINATED BY' is nonempty, lines are also terminated with `FIELDS TERMINATED BY'. * If the `FIELDS TERMINATED BY' and `FIELDS ENCLOSED BY' values are both empty (`'''), a fixed-row (nondelimited) format is used. With fixed-row format, no delimiters are used between fields (but you can still have a line terminator). Instead, column values are read and written using a field width wide enough to hold all values in the field. For *Note `TINYINT': numeric-types, *Note `SMALLINT': numeric-types, *Note `MEDIUMINT': numeric-types, *Note `INT': numeric-types, and *Note `BIGINT': numeric-types, the field widths are 4, 6, 8, 11, and 20, respectively, no matter what the declared display width is. `LINES TERMINATED BY' is still used to separate lines. If a line does not contain all fields, the rest of the columns are set to their default values. If you do not have a line terminator, you should set this to `'''. In this case, the text file must contain all fields for each row. Fixed-row format also affects handling of `NULL' values, as described later. Note that fixed-size format does not work if you are using a multi-byte character set. Handling of `NULL' values varies according to the `FIELDS' and `LINES' options in use: * For the default `FIELDS' and `LINES' values, `NULL' is written as a field value of `\N' for output, and a field value of `\N' is read as `NULL' for input (assuming that the `ESCAPED BY' character is ``\''). * If `FIELDS ENCLOSED BY' is not empty, a field containing the literal word `NULL' as its value is read as a `NULL' value. This differs from the word `NULL' enclosed within `FIELDS ENCLOSED BY' characters, which is read as the string `'NULL''. * If `FIELDS ESCAPED BY' is empty, `NULL' is written as the word `NULL'. * With fixed-row format (which is used when `FIELDS TERMINATED BY' and `FIELDS ENCLOSED BY' are both empty), `NULL' is written as an empty string. Note that this causes both `NULL' values and empty strings in the table to be indistinguishable when written to the file because both are written as empty strings. If you need to be able to tell the two apart when reading the file back in, you should not use fixed-row format. An attempt to load `NULL' into a `NOT NULL' column causes assignment of the implicit default value for the column's data type and a warning, or an error in strict SQL mode. Implicit default values are discussed in *Note data-type-defaults::. Some cases are not supported by *Note `LOAD DATA INFILE': load-data.: * Fixed-size rows (`FIELDS TERMINATED BY' and `FIELDS ENCLOSED BY' both empty) and *Note `BLOB': blob. or *Note `TEXT': blob. columns. * If you specify one separator that is the same as or a prefix of another, *Note `LOAD DATA INFILE': load-data. cannot interpret the input properly. For example, the following `FIELDS' clause would cause problems: FIELDS TERMINATED BY '"' ENCLOSED BY '"' * If `FIELDS ESCAPED BY' is empty, a field value that contains an occurrence of `FIELDS ENCLOSED BY' or `LINES TERMINATED BY' followed by the `FIELDS TERMINATED BY' value causes *Note `LOAD DATA INFILE': load-data. to stop reading a field or line too early. This happens because *Note `LOAD DATA INFILE': load-data. cannot properly determine where the field or line value ends. The following example loads all columns of the `persondata' table: LOAD DATA INFILE 'persondata.txt' INTO TABLE persondata; By default, when no column list is provided at the end of the *Note `LOAD DATA INFILE': load-data. statement, input lines are expected to contain a field for each table column. If you want to load only some of a table's columns, specify a column list: LOAD DATA INFILE 'persondata.txt' INTO TABLE persondata (col1,col2,...); You must also specify a column list if the order of the fields in the input file differs from the order of the columns in the table. Otherwise, MySQL cannot tell how to match input fields with table columns. The column list can contain either column names or user variables. With user variables, the `SET' clause enables you to perform transformations on their values before assigning the result to columns. User variables in the `SET' clause can be used in several ways. The following example uses the first input column directly for the value of `t1.column1', and assigns the second input column to a user variable that is subjected to a division operation before being used for the value of `t1.column2': LOAD DATA INFILE 'file.txt' INTO TABLE t1 (column1, @var1) SET column2 = @var1/100; The `SET' clause can be used to supply values not derived from the input file. The following statement sets `column3' to the current date and time: LOAD DATA INFILE 'file.txt' INTO TABLE t1 (column1, column2) SET column3 = CURRENT_TIMESTAMP; You can also discard an input value by assigning it to a user variable and not assigning the variable to a table column: LOAD DATA INFILE 'file.txt' INTO TABLE t1 (column1, @dummy, column2, @dummy, column3); Use of the column/variable list and `SET' clause is subject to the following restrictions: * Assignments in the `SET' clause should have only column names on the left hand side of assignment operators. * You can use subqueries in the right hand side of `SET' assignments. A subquery that returns a value to be assigned to a column may be a scalar subquery only. Also, you cannot use a subquery to select from the table that is being loaded. * Lines ignored by an `IGNORE' clause are not processed for the column/variable list or `SET' clause. * User variables cannot be used when loading data with fixed-row format because user variables do not have a display width. When processing an input line, *Note `LOAD DATA': load-data. splits it into fields and uses the values according to the column/variable list and the `SET' clause, if they are present. Then the resulting row is inserted into the table. If there are `BEFORE INSERT' or `AFTER INSERT' triggers for the table, they are activated before or after inserting the row, respectively. If an input line has too many fields, the extra fields are ignored and the number of warnings is incremented. If an input line has too few fields, the table columns for which input fields are missing are set to their default values. Default value assignment is described in *Note data-type-defaults::. An empty field value is interpreted differently than if the field value is missing: * For string types, the column is set to the empty string. * For numeric types, the column is set to `0'. * For date and time types, the column is set to the appropriate `zero' value for the type. See *Note date-and-time-types::. These are the same values that result if you assign an empty string explicitly to a string, numeric, or date or time type explicitly in an *Note `INSERT': insert. or *Note `UPDATE': update. statement. *Note `TIMESTAMP': datetime. columns are set to the current date and time only if there is a `NULL' value for the column (that is, `\N') and the column is not declared to permit `NULL' values, or if the *Note `TIMESTAMP': datetime. column's default value is the current timestamp and it is omitted from the field list when a field list is specified. *Note `LOAD DATA INFILE': load-data. regards all input as strings, so you cannot use numeric values for *Note `ENUM': enum. or *Note `SET': set. columns the way you can with *Note `INSERT': insert. statements. All *Note `ENUM': enum. and *Note `SET': set. values must be specified as strings. *Note `BIT': numeric-types. values cannot be loaded using binary notation (for example, `b'011010''). To work around this, specify the values as regular integers and use the `SET' clause to convert them so that MySQL performs a numeric type conversion and loads them into the *Note `BIT': numeric-types. column properly: shell> cat /tmp/bit_test.txt 2 127 shell> mysql test mysql> LOAD DATA INFILE '/tmp/bit_test.txt' -> INTO TABLE bit_test (@var1) SET b= CAST(@var1 AS UNSIGNED); Query OK, 2 rows affected (0.00 sec) Records: 2 Deleted: 0 Skipped: 0 Warnings: 0 mysql> SELECT BIN(b+0) FROM bit_test; +----------+ | bin(b+0) | +----------+ | 10 | | 1111111 | +----------+ 2 rows in set (0.00 sec) When the *Note `LOAD DATA INFILE': load-data. statement finishes, it returns an information string in the following format: Records: 1 Deleted: 0 Skipped: 0 Warnings: 0 If you are using the C API, you can get information about the statement by calling the *Note `mysql_info()': mysql-info. function. See *Note mysql-info::. Warnings occur under the same circumstances as when values are inserted using the *Note `INSERT': insert. statement (see *Note insert::), except that *Note `LOAD DATA INFILE': load-data. also generates warnings when there are too few or too many fields in the input row. The warnings are not stored anywhere; the number of warnings can be used only as an indication of whether everything went well. You can use *Note `SHOW WARNINGS': show-warnings. to get a list of the first `max_error_count' warnings as information about what went wrong. See *Note show-warnings::.  File: manual.info, Node: replace, Next: select, Prev: load-data, Up: sql-syntax-data-manipulation 13.2.7 `REPLACE' Syntax ----------------------- REPLACE [LOW_PRIORITY | DELAYED] [INTO] TBL_NAME [(COL_NAME,...)] {VALUES | VALUE} ({EXPR | DEFAULT},...),(...),... Or: REPLACE [LOW_PRIORITY | DELAYED] [INTO] TBL_NAME SET COL_NAME={EXPR | DEFAULT}, ... Or: REPLACE [LOW_PRIORITY | DELAYED] [INTO] TBL_NAME [(COL_NAME,...)] SELECT ... *Note `REPLACE': replace. works exactly like *Note `INSERT': insert, except that if an old row in the table has the same value as a new row for a `PRIMARY KEY' or a `UNIQUE' index, the old row is deleted before the new row is inserted. See *Note insert::. *Note `REPLACE': replace. is a MySQL extension to the SQL standard. It either inserts, or _deletes_ and inserts. For another MySQL extension to standard SQL--that either inserts or _updates_--see *Note insert-on-duplicate::. Note that unless the table has a `PRIMARY KEY' or `UNIQUE' index, using a *Note `REPLACE': replace. statement makes no sense. It becomes equivalent to *Note `INSERT': insert, because there is no index to be used to determine whether a new row duplicates another. Values for all columns are taken from the values specified in the *Note `REPLACE': replace. statement. Any missing columns are set to their default values, just as happens for *Note `INSERT': insert. You cannot refer to values from the current row and use them in the new row. If you use an assignment such as `SET COL_NAME = COL_NAME + 1', the reference to the column name on the right hand side is treated as `DEFAULT(COL_NAME)', so the assignment is equivalent to `SET COL_NAME = DEFAULT(COL_NAME) + 1'. To use *Note `REPLACE': replace, you must have both the `INSERT' and `DELETE' privileges for the table. The *Note `REPLACE': replace. statement returns a count to indicate the number of rows affected. This is the sum of the rows deleted and inserted. If the count is 1 for a single-row *Note `REPLACE': replace, a row was inserted and no rows were deleted. If the count is greater than 1, one or more old rows were deleted before the new row was inserted. It is possible for a single row to replace more than one old row if the table contains multiple unique indexes and the new row duplicates values for different old rows in different unique indexes. The affected-rows count makes it easy to determine whether *Note `REPLACE': replace. only added a row or whether it also replaced any rows: Check whether the count is 1 (added) or greater (replaced). If you are using the C API, the affected-rows count can be obtained using the *Note `mysql_affected_rows()': mysql-affected-rows. function. Currently, you cannot replace into a table and select from the same table in a subquery. MySQL uses the following algorithm for *Note `REPLACE': replace. (and `LOAD DATA ... REPLACE'): 1. Try to insert the new row into the table 2. While the insertion fails because a duplicate-key error occurs for a primary key or unique index: 1. Delete from the table the conflicting row that has the duplicate key value 2. Try again to insert the new row into the table It is possible that in the case of a duplicate-key error, a storage engine may perform the `REPLACE' as an update rather than a delete plus insert, but the semantics are the same. There are no user-visible effects other than a possible difference in how the storage engine increments `Handler_XXX' status variables.  File: manual.info, Node: select, Next: subqueries, Prev: replace, Up: sql-syntax-data-manipulation 13.2.8 `SELECT' Syntax ---------------------- * Menu: * join:: `JOIN' Syntax * index-hints:: Index Hint Syntax * union:: `UNION' Syntax SELECT [ALL | DISTINCT | DISTINCTROW ] [HIGH_PRIORITY] [STRAIGHT_JOIN] [SQL_SMALL_RESULT] [SQL_BIG_RESULT] [SQL_BUFFER_RESULT] [SQL_CACHE | SQL_NO_CACHE] [SQL_CALC_FOUND_ROWS] SELECT_EXPR [, SELECT_EXPR ...] [FROM TABLE_REFERENCES [WHERE WHERE_CONDITION] [GROUP BY {COL_NAME | EXPR | POSITION} [ASC | DESC], ... [WITH ROLLUP]] [HAVING WHERE_CONDITION] [ORDER BY {COL_NAME | EXPR | POSITION} [ASC | DESC], ...] [LIMIT {[OFFSET,] ROW_COUNT | ROW_COUNT OFFSET OFFSET}] [PROCEDURE PROCEDURE_NAME(ARGUMENT_LIST)] [INTO OUTFILE 'FILE_NAME' [CHARACTER SET CHARSET_NAME] EXPORT_OPTIONS | INTO DUMPFILE 'FILE_NAME' | INTO VAR_NAME [, VAR_NAME]] [FOR UPDATE | LOCK IN SHARE MODE]] *Note `SELECT': select. is used to retrieve rows selected from one or more tables, and can include *Note `UNION': union. statements and subqueries. See *Note union::, and *Note subqueries::. The most commonly used clauses of *Note `SELECT': select. statements are these: * Each SELECT_EXPR indicates a column that you want to retrieve. There must be at least one SELECT_EXPR. * TABLE_REFERENCES indicates the table or tables from which to retrieve rows. Its syntax is described in *Note join::. * The `WHERE' clause, if given, indicates the condition or conditions that rows must satisfy to be selected. WHERE_CONDITION is an expression that evaluates to true for each row to be selected. The statement selects all rows if there is no `WHERE' clause. In the `WHERE' expression, you can use any of the functions and operators that MySQL supports, except for aggregate (summary) functions. See *Note expressions::, and *Note functions::. *Note `SELECT': select. can also be used to retrieve rows computed without reference to any table. For example: mysql> SELECT 1 + 1; -> 2 You are permitted to specify `DUAL' as a dummy table name in situations where no tables are referenced: mysql> SELECT 1 + 1 FROM DUAL; -> 2 `DUAL' is purely for the convenience of people who require that all *Note `SELECT': select. statements should have `FROM' and possibly other clauses. MySQL may ignore the clauses. MySQL does not require `FROM DUAL' if no tables are referenced. In general, clauses used must be given in exactly the order shown in the syntax description. For example, a `HAVING' clause must come after any `GROUP BY' clause and before any `ORDER BY' clause. The exception is that the `INTO' clause can appear either as shown in the syntax description or immediately following the SELECT_EXPR list. The list of SELECT_EXPR terms comprises the select list that indicates which columns to retrieve. Terms specify a column or expression or can use `*'-shorthand: * A select list consisting only of a single unqualified `*' can be used as shorthand to select all columns from all tables: SELECT * FROM t1 INNER JOIN t2 ... * `TBL_NAME.*' can be used as a qualified shorthand to select all columns from the named table: SELECT t1.*, t2.* FROM t1 INNER JOIN t2 ... * Use of an unqualified `*' with other items in the select list may produce a parse error. To avoid this problem, use a qualified `TBL_NAME.*' reference SELECT AVG(score), t1.* FROM t1 ... The following list provides additional information about other `SELECT' clauses: * A SELECT_EXPR can be given an alias using `AS ALIAS_NAME'. The alias is used as the expression's column name and can be used in `GROUP BY', `ORDER BY', or `HAVING' clauses. For example: SELECT CONCAT(last_name,', ',first_name) AS full_name FROM mytable ORDER BY full_name; The `AS' keyword is optional when aliasing a SELECT_EXPR with an identifier. The preceding example could have been written like this: SELECT CONCAT(last_name,', ',first_name) full_name FROM mytable ORDER BY full_name; However, because the `AS' is optional, a subtle problem can occur if you forget the comma between two SELECT_EXPR expressions: MySQL interprets the second as an alias name. For example, in the following statement, `columnb' is treated as an alias name: SELECT columna columnb FROM mytable; For this reason, it is good practice to be in the habit of using `AS' explicitly when specifying column aliases. It is not permissible to refer to a column alias in a `WHERE' clause, because the column value might not yet be determined when the `WHERE' clause is executed. See *Note problems-with-alias::. * The `FROM TABLE_REFERENCES' clause indicates the table or tables from which to retrieve rows. If you name more than one table, you are performing a join. For information on join syntax, see *Note join::. For each table specified, you can optionally specify an alias. TBL_NAME [[AS] ALIAS] [INDEX_HINT] The use of index hints provides the optimizer with information about how to choose indexes during query processing. For a description of the syntax for specifying these hints, see *Note index-hints::. You can use `SET max_seeks_for_key=VALUE' as an alternative way to force MySQL to prefer key scans instead of table scans. See *Note server-system-variables::. * You can refer to a table within the default database as TBL_NAME, or as DB_NAME.TBL_NAME to specify a database explicitly. You can refer to a column as COL_NAME, TBL_NAME.COL_NAME, or DB_NAME.TBL_NAME.COL_NAME. You need not specify a TBL_NAME or DB_NAME.TBL_NAME prefix for a column reference unless the reference would be ambiguous. See *Note identifier-qualifiers::, for examples of ambiguity that require the more explicit column reference forms. * A table reference can be aliased using `TBL_NAME AS ALIAS_NAME' or TBL_NAME ALIAS_NAME: SELECT t1.name, t2.salary FROM employee AS t1, info AS t2 WHERE t1.name = t2.name; SELECT t1.name, t2.salary FROM employee t1, info t2 WHERE t1.name = t2.name; * Columns selected for output can be referred to in `ORDER BY' and `GROUP BY' clauses using column names, column aliases, or column positions. Column positions are integers and begin with 1: SELECT college, region, seed FROM tournament ORDER BY region, seed; SELECT college, region AS r, seed AS s FROM tournament ORDER BY r, s; SELECT college, region, seed FROM tournament ORDER BY 2, 3; To sort in reverse order, add the `DESC' (descending) keyword to the name of the column in the `ORDER BY' clause that you are sorting by. The default is ascending order; this can be specified explicitly using the `ASC' keyword. If `ORDER BY' occurs within a subquery and also is applied in the outer query, the outermost `ORDER BY' takes precedence. For example, results for the following statement are sorted in descending order, not ascending order: (SELECT ... ORDER BY a) ORDER BY a DESC; Use of column positions is deprecated because the syntax has been removed from the SQL standard. * If you use `GROUP BY', output rows are sorted according to the `GROUP BY' columns as if you had an `ORDER BY' for the same columns. To avoid the overhead of sorting that `GROUP BY' produces, add `ORDER BY NULL': SELECT a, COUNT(b) FROM test_table GROUP BY a ORDER BY NULL; * MySQL extends the `GROUP BY' clause so that you can also specify `ASC' and `DESC' after columns named in the clause: SELECT a, COUNT(b) FROM test_table GROUP BY a DESC; * MySQL extends the use of `GROUP BY' to permit selecting fields that are not mentioned in the `GROUP BY' clause. If you are not getting the results that you expect from your query, please read the description of `GROUP BY' found in *Note group-by-functions-and-modifiers::. * `GROUP BY' permits a `WITH ROLLUP' modifier. See *Note group-by-modifiers::. * The `HAVING' clause is applied nearly last, just before items are sent to the client, with no optimization. (`LIMIT' is applied after `HAVING'.) The SQL standard requires that `HAVING' must reference only columns in the `GROUP BY' clause or columns used in aggregate functions. However, MySQL supports an extension to this behavior, and permits `HAVING' to refer to columns in the *Note `SELECT': select. list and columns in outer subqueries as well. If the `HAVING' clause refers to a column that is ambiguous, a warning occurs. In the following statement, `col2' is ambiguous because it is used as both an alias and a column name: SELECT COUNT(col1) AS col2 FROM t GROUP BY col2 HAVING col2 = 2; Preference is given to standard SQL behavior, so if a `HAVING' column name is used both in `GROUP BY' and as an aliased column in the output column list, preference is given to the column in the `GROUP BY' column. * Do not use `HAVING' for items that should be in the `WHERE' clause. For example, do not write the following: SELECT COL_NAME FROM TBL_NAME HAVING COL_NAME > 0; Write this instead: SELECT COL_NAME FROM TBL_NAME WHERE COL_NAME > 0; * The `HAVING' clause can refer to aggregate functions, which the `WHERE' clause cannot: SELECT user, MAX(salary) FROM users GROUP BY user HAVING MAX(salary) > 10; (This did not work in some older versions of MySQL.) * MySQL permits duplicate column names. That is, there can be more than one SELECT_EXPR with the same name. This is an extension to standard SQL. Because MySQL also permits `GROUP BY' and `HAVING' to refer to SELECT_EXPR values, this can result in an ambiguity: SELECT 12 AS a, a FROM t GROUP BY a; In that statement, both columns have the name `a'. To ensure that the correct column is used for grouping, use different names for each SELECT_EXPR. * MySQL resolves unqualified column or alias references in `ORDER BY' clauses by searching in the SELECT_EXPR values, then in the columns of the tables in the `FROM' clause. For `GROUP BY' or `HAVING' clauses, it searches the `FROM' clause before searching in the SELECT_EXPR values. (For `GROUP BY' and `HAVING', this differs from the pre-MySQL 5.0 behavior that used the same rules as for `ORDER BY'.) * The `LIMIT' clause can be used to constrain the number of rows returned by the *Note `SELECT': select. statement. `LIMIT' takes one or two numeric arguments, which must both be nonnegative integer constants (except when using prepared statements). With two arguments, the first argument specifies the offset of the first row to return, and the second specifies the maximum number of rows to return. The offset of the initial row is 0 (not 1): SELECT * FROM tbl LIMIT 5,10; # Retrieve rows 6-15 To retrieve all rows from a certain offset up to the end of the result set, you can use some large number for the second parameter. This statement retrieves all rows from the 96th row to the last: SELECT * FROM tbl LIMIT 95,18446744073709551615; With one argument, the value specifies the number of rows to return from the beginning of the result set: SELECT * FROM tbl LIMIT 5; # Retrieve first 5 rows In other words, `LIMIT ROW_COUNT' is equivalent to `LIMIT 0, ROW_COUNT'. For prepared statements, you can use placeholders. The following statements will return one row from the `tbl' table: SET @a=1; PREPARE STMT FROM 'SELECT * FROM tbl LIMIT ?'; EXECUTE STMT USING @a; The following statements will return the second to sixth row from the `tbl' table: SET @skip=1; SET @numrows=5; PREPARE STMT FROM 'SELECT * FROM tbl LIMIT ?, ?'; EXECUTE STMT USING @skip, @numrows; For compatibility with PostgreSQL, MySQL also supports the `LIMIT ROW_COUNT OFFSET OFFSET' syntax. If `LIMIT' occurs within a subquery and also is applied in the outer query, the outermost `LIMIT' takes precedence. For example, the following statement produces two rows, not one: (SELECT ... LIMIT 1) LIMIT 2; * A `PROCEDURE' clause names a procedure that should process the data in the result set. For an example, see *Note procedure-analyse::, which describes `ANALYSE', a procedure that can be used to obtain suggestions for optimal column data types that may help reduce table sizes. * The `SELECT ... INTO OUTFILE 'FILE_NAME'' form of *Note `SELECT': select. writes the selected rows to a file. The file is created on the server host, so you must have the `FILE' privilege to use this syntax. FILE_NAME cannot be an existing file, which among other things prevents files such as `/etc/passwd' and database tables from being destroyed. As of MySQL 5.1.6, the `character_set_filesystem' system variable controls the interpretation of the file name. The *Note `SELECT ... INTO OUTFILE': select. statement is intended primarily to let you very quickly dump a table to a text file on the server machine. If you want to create the resulting file on some other host than the server host, you normally cannot use *Note `SELECT ... INTO OUTFILE': select. since there is no way to write a path to the file relative to the server host's file system. However, if the MySQL client software is installed on the remote machine, you can instead use a client command such as `mysql -e "SELECT ..." > FILE_NAME' to generate the file on the client host. It is also possible to create the resulting file on a different host other than the server host, if the location of the file on the remote host can be accessed using a network-mapped path on the server's file system. In this case, the presence of *Note `mysql': mysql. (or some other MySQL client program) is not required on the target host. *Note `SELECT ... INTO OUTFILE': select. is the complement of *Note `LOAD DATA INFILE': load-data. Column values are written converted to the character set specified in the `CHARACTER SET' clause, which is available as of MySQL 5.1.38. Prior to 5.1.38 or if no such clause is present, values are dumped using the `binary' character set. In effect, there is no character set conversion. If a table contains columns in several character sets, the output data file will as well and you may not be able to reload the file correctly. The syntax for the EXPORT_OPTIONS part of the statement consists of the same `FIELDS' and `LINES' clauses that are used with the *Note `LOAD DATA INFILE': load-data. statement. See *Note load-data::, for information about the `FIELDS' and `LINES' clauses, including their default values and permissible values. `FIELDS ESCAPED BY' controls how to write special characters. If the `FIELDS ESCAPED BY' character is not empty, it is used as a prefix that precedes following characters on output: * The `FIELDS ESCAPED BY' character * The `FIELDS [OPTIONALLY] ENCLOSED BY' character * The first character of the `FIELDS TERMINATED BY' and `LINES TERMINATED BY' values * ASCII `NUL' (the zero-valued byte; what is actually written following the escape character is ASCII ``0'', not a zero-valued byte) The `FIELDS TERMINATED BY', `ENCLOSED BY', `ESCAPED BY', or `LINES TERMINATED BY' characters _must_ be escaped so that you can read the file back in reliably. ASCII `NUL' is escaped to make it easier to view with some pagers. The resulting file does not have to conform to SQL syntax, so nothing else need be escaped. If the `FIELDS ESCAPED BY' character is empty, no characters are escaped and `NULL' is output as `NULL', not `\N'. It is probably not a good idea to specify an empty escape character, particularly if field values in your data contain any of the characters in the list just given. Here is an example that produces a file in the comma-separated values (CSV) format used by many programs: SELECT a,b,a+b INTO OUTFILE '/tmp/result.txt' FIELDS TERMINATED BY ',' OPTIONALLY ENCLOSED BY '"' LINES TERMINATED BY '\n' FROM test_table; * If you use `INTO DUMPFILE' instead of `INTO OUTFILE', MySQL writes only one row into the file, without any column or line termination and without performing any escape processing. This is useful if you want to store a *Note `BLOB': blob. value in a file. * *Note*: Any file created by `INTO OUTFILE' or `INTO DUMPFILE' is writable by all users on the server host. The reason for this is that the MySQL server cannot create a file that is owned by anyone other than the user under whose account it is running. (You should _never_ run *Note `mysqld': mysqld. as `root' for this and other reasons.) The file thus must be world-writable so that you can manipulate its contents. If the `secure_file_priv' system variable is set to a nonempty directory name, the file to be written must be located in that directory. * The `INTO' clause can name a list of one or more variables, which can be user-defined variables, or parameters or local variables within a stored function or procedure body (see *Note select-into-statement::). The selected values are assigned to the variables. The number of variables must match the number of columns. The query should return a single row. If the query returns no rows, a warning with error code 1329 occurs (`No data'), and the variable values remain unchanged. If the query returns multiple rows, error 1172 occurs (`Result consisted of more than one row'). If it is possible that the statement may retrieve multiple rows, you can use `LIMIT 1' to limit the result set to a single row. In the context of such statements that occur as part of events executed by the Event Scheduler, diagnostics messages (not only errors, but also warnings) are written to the error log, and, on Windows, to the application event log. For additional information, see *Note events-status-info::. * The *Note `SELECT': select. syntax description at the beginning this section shows the `INTO' clause near the end of the statement. It is also possible to use `INTO' immediately following the SELECT_EXPR list. * An `INTO' clause should not be used in a nested *Note `SELECT': select. because such a *Note `SELECT': select. must return its result to the outer context. * If you use `FOR UPDATE' with a storage engine that uses page or row locks, rows examined by the query are write-locked until the end of the current transaction. Using `LOCK IN SHARE MODE' sets a shared lock that permits other transactions to read the examined rows but not to update or delete them. See *Note innodb-locking-reads::. Following the *Note `SELECT': select. keyword, you can use a number of options that affect the operation of the statement. `HIGH_PRIORITY', `STRAIGHT_JOIN', and options beginning with `SQL_' are MySQL extensions to standard SQL. * The `ALL' and `DISTINCT' options specify whether duplicate rows should be returned. `ALL' (the default) specifies that all matching rows should be returned, including duplicates. `DISTINCT' specifies removal of duplicate rows from the result set. It is an error to specify both options. `DISTINCTROW' is a synonym for `DISTINCT'. * `HIGH_PRIORITY' gives the *Note `SELECT': select. higher priority than a statement that updates a table. You should use this only for queries that are very fast and must be done at once. A `SELECT HIGH_PRIORITY' query that is issued while the table is locked for reading runs even if there is an update statement waiting for the table to be free. This affects only storage engines that use only table-level locking (such as `MyISAM', `MEMORY', and `MERGE'). `HIGH_PRIORITY' cannot be used with *Note `SELECT': select. statements that are part of a *Note `UNION': union. * `STRAIGHT_JOIN' forces the optimizer to join the tables in the order in which they are listed in the `FROM' clause. You can use this to speed up a query if the optimizer joins the tables in nonoptimal order. `STRAIGHT_JOIN' also can be used in the TABLE_REFERENCES list. See *Note join::. `STRAIGHT_JOIN' does not apply to any table that the optimizer treats as a `const' or `system' table. Such a table produces a single row, is read during the optimization phase of query execution, and references to its columns are replaced with the appropriate column values before query execution proceeds. These tables will appear first in the query plan displayed by *Note `EXPLAIN': explain. See *Note using-explain::. This exception may not apply to `const' or `system' tables that are used on the `NULL'-complemented side of an outer join (that is, the right-side table of a `LEFT JOIN' or the left-side table of a `RIGHT JOIN'. * `SQL_BIG_RESULT' or `SQL_SMALL_RESULT' can be used with `GROUP BY' or `DISTINCT' to tell the optimizer that the result set has many rows or is small, respectively. For `SQL_BIG_RESULT', MySQL directly uses disk-based temporary tables if needed, and prefers sorting to using a temporary table with a key on the `GROUP BY' elements. For `SQL_SMALL_RESULT', MySQL uses fast temporary tables to store the resulting table instead of using sorting. This should not normally be needed. * `SQL_BUFFER_RESULT' forces the result to be put into a temporary table. This helps MySQL free the table locks early and helps in cases where it takes a long time to send the result set to the client. This option can be used only for top-level *Note `SELECT': select. statements, not for subqueries or following *Note `UNION': union. * `SQL_CALC_FOUND_ROWS' tells MySQL to calculate how many rows there would be in the result set, disregarding any `LIMIT' clause. The number of rows can then be retrieved with `SELECT FOUND_ROWS()'. See *Note information-functions::. * The `SQL_CACHE' and `SQL_NO_CACHE' options affect caching of query results in the query cache (see *Note query-cache::). `SQL_CACHE' tells MySQL to store the result in the query cache if it is cacheable and the value of the `query_cache_type' system variable is `2' or `DEMAND'. `SQL_NO_CACHE' tells MySQL not to store the result in the query cache. For a query that uses *Note `UNION': union, subqueries, or views, the following rules apply: * `SQL_NO_CACHE' applies if it appears in any *Note `SELECT': select. in the query. * For a cacheable query, `SQL_CACHE' applies if it appears in the first *Note `SELECT': select. of the query, or in the first *Note `SELECT': select. of a view referred to by the query.  File: manual.info, Node: join, Next: index-hints, Prev: select, Up: select 13.2.8.1 `JOIN' Syntax ...................... MySQL supports the following `JOIN' syntaxes for the TABLE_REFERENCES part of *Note `SELECT': select. statements and multiple-table *Note `DELETE': delete. and *Note `UPDATE': update. statements: TABLE_REFERENCES: TABLE_REFERENCE [, TABLE_REFERENCE] ... TABLE_REFERENCE: TABLE_FACTOR | JOIN_TABLE TABLE_FACTOR: TBL_NAME [[AS] ALIAS] [INDEX_HINT_LIST] | TABLE_SUBQUERY [AS] ALIAS | ( TABLE_REFERENCES ) | { OJ TABLE_REFERENCE LEFT OUTER JOIN TABLE_REFERENCE ON CONDITIONAL_EXPR } JOIN_TABLE: TABLE_REFERENCE [INNER | CROSS] JOIN TABLE_FACTOR [JOIN_CONDITION] | TABLE_REFERENCE STRAIGHT_JOIN TABLE_FACTOR | TABLE_REFERENCE STRAIGHT_JOIN TABLE_FACTOR ON CONDITIONAL_EXPR | TABLE_REFERENCE {LEFT|RIGHT} [OUTER] JOIN TABLE_REFERENCE JOIN_CONDITION | TABLE_REFERENCE NATURAL [{LEFT|RIGHT} [OUTER]] JOIN TABLE_FACTOR JOIN_CONDITION: ON CONDITIONAL_EXPR | USING (COLUMN_LIST) INDEX_HINT_LIST: INDEX_HINT [, INDEX_HINT] ... INDEX_HINT: USE {INDEX|KEY} [{FOR {JOIN|ORDER BY|GROUP BY}] ([INDEX_LIST]) | IGNORE {INDEX|KEY} [{FOR {JOIN|ORDER BY|GROUP BY}] (INDEX_LIST) | FORCE {INDEX|KEY} [{FOR {JOIN|ORDER BY|GROUP BY}] (INDEX_LIST) INDEX_LIST: INDEX_NAME [, INDEX_NAME] ... A table reference is also known as a join expression. The syntax of TABLE_FACTOR is extended in comparison with the SQL Standard. The latter accepts only TABLE_REFERENCE, not a list of them inside a pair of parentheses. This is a conservative extension if we consider each comma in a list of TABLE_REFERENCE items as equivalent to an inner join. For example: SELECT * FROM t1 LEFT JOIN (t2, t3, t4) ON (t2.a=t1.a AND t3.b=t1.b AND t4.c=t1.c) is equivalent to: SELECT * FROM t1 LEFT JOIN (t2 CROSS JOIN t3 CROSS JOIN t4) ON (t2.a=t1.a AND t3.b=t1.b AND t4.c=t1.c) In MySQL, `CROSS JOIN' is a syntactic equivalent to `INNER JOIN' (they can replace each other). In standard SQL, they are not equivalent. `INNER JOIN' is used with an `ON' clause, `CROSS JOIN' is used otherwise. In general, parentheses can be ignored in join expressions containing only inner join operations. MySQL also supports nested joins (see *Note nested-join-optimization::). Index hints can be specified to affect how the MySQL optimizer makes use of indexes. For more information, see *Note index-hints::. The following list describes general factors to take into account when writing joins. * A table reference can be aliased using `TBL_NAME AS ALIAS_NAME' or TBL_NAME ALIAS_NAME: SELECT t1.name, t2.salary FROM employee AS t1 INNER JOIN info AS t2 ON t1.name = t2.name; SELECT t1.name, t2.salary FROM employee t1 INNER JOIN info t2 ON t1.name = t2.name; * A TABLE_SUBQUERY is also known as a subquery in the `FROM' clause. Such subqueries _must_ include an alias to give the subquery result a table name. A trivial example follows; see also *Note from-clause-subqueries::. SELECT * FROM (SELECT 1, 2, 3) AS t1; * `INNER JOIN' and `,' (comma) are semantically equivalent in the absence of a join condition: both produce a Cartesian product between the specified tables (that is, each and every row in the first table is joined to each and every row in the second table). However, the precedence of the comma operator is less than of `INNER JOIN', `CROSS JOIN', `LEFT JOIN', and so on. If you mix comma joins with the other join types when there is a join condition, an error of the form `Unknown column 'COL_NAME' in 'on clause'' may occur. Information about dealing with this problem is given later in this section. * The CONDITIONAL_EXPR used with `ON' is any conditional expression of the form that can be used in a `WHERE' clause. Generally, you should use the `ON' clause for conditions that specify how to join tables, and the `WHERE' clause to restrict which rows you want in the result set. * If there is no matching row for the right table in the `ON' or `USING' part in a `LEFT JOIN', a row with all columns set to `NULL' is used for the right table. You can use this fact to find rows in a table that have no counterpart in another table: SELECT left_tbl.* FROM left_tbl LEFT JOIN right_tbl ON left_tbl.id = right_tbl.id WHERE right_tbl.id IS NULL; This example finds all rows in `left_tbl' with an `id' value that is not present in `right_tbl' (that is, all rows in `left_tbl' with no corresponding row in `right_tbl'). This assumes that `right_tbl.id' is declared `NOT NULL'. See *Note left-join-optimization::. * The `USING(COLUMN_LIST)' clause names a list of columns that must exist in both tables. If tables `a' and `b' both contain columns `c1', `c2', and `c3', the following join compares corresponding columns from the two tables: a LEFT JOIN b USING (c1,c2,c3) * The `NATURAL [LEFT] JOIN' of two tables is defined to be semantically equivalent to an `INNER JOIN' or a `LEFT JOIN' with a `USING' clause that names all columns that exist in both tables. * `RIGHT JOIN' works analogously to `LEFT JOIN'. To keep code portable across databases, it is recommended that you use `LEFT JOIN' instead of `RIGHT JOIN'. * The `{ OJ ... LEFT OUTER JOIN ...}' syntax shown in the join syntax description exists only for compatibility with ODBC. The curly braces in the syntax should be written literally; they are not metasyntax as used elsewhere in syntax descriptions. SELECT left_tbl.* FROM { OJ left_tbl LEFT OUTER JOIN right_tbl ON left_tbl.id = right_tbl.id } WHERE right_tbl.id IS NULL; As of MySQL 5.1.24, you can use other types of joins within `{ OJ ... }', such as `INNER JOIN' or `RIGHT OUTER JOIN'. This helps with compatibility with some third-party applications, but is not official ODBC syntax. * `STRAIGHT_JOIN' is similar to `JOIN', except that the left table is always read before the right table. This can be used for those (few) cases for which the join optimizer puts the tables in the wrong order. Some join examples: SELECT * FROM table1, table2; SELECT * FROM table1 INNER JOIN table2 ON table1.id=table2.id; SELECT * FROM table1 LEFT JOIN table2 ON table1.id=table2.id; SELECT * FROM table1 LEFT JOIN table2 USING (id); SELECT * FROM table1 LEFT JOIN table2 ON table1.id=table2.id LEFT JOIN table3 ON table2.id=table3.id; *Join Processing Changes in MySQL 5.0.12* *Note*: Natural joins and joins with `USING', including outer join variants, are processed according to the SQL:2003 standard. The goal was to align the syntax and semantics of MySQL with respect to `NATURAL JOIN' and `JOIN ... USING' according to SQL:2003. However, these changes in join processing can result in different output columns for some joins. Also, some queries that appeared to work correctly in older versions (prior to 5.0.12) must be rewritten to comply with the standard. These changes have five main aspects: * The way that MySQL determines the result columns of `NATURAL' or `USING' join operations (and thus the result of the entire `FROM' clause). * Expansion of `SELECT *' and `SELECT TBL_NAME.*' into a list of selected columns. * Resolution of column names in `NATURAL' or `USING' joins. * Transformation of `NATURAL' or `USING' joins into `JOIN ... ON'. * Resolution of column names in the `ON' condition of a `JOIN ... ON'. The following list provides more detail about several effects of current join processing versus join processing in older versions. The term `previously' means `prior to MySQL 5.0.12.' * The columns of a `NATURAL' join or a `USING' join may be different from previously. Specifically, redundant output columns no longer appear, and the order of columns for `SELECT *' expansion may be different from before. Consider this set of statements: CREATE TABLE t1 (i INT, j INT); CREATE TABLE t2 (k INT, j INT); INSERT INTO t1 VALUES(1,1); INSERT INTO t2 VALUES(1,1); SELECT * FROM t1 NATURAL JOIN t2; SELECT * FROM t1 JOIN t2 USING (j); Previously, the statements produced this output: +------+------+------+------+ | i | j | k | j | +------+------+------+------+ | 1 | 1 | 1 | 1 | +------+------+------+------+ +------+------+------+------+ | i | j | k | j | +------+------+------+------+ | 1 | 1 | 1 | 1 | +------+------+------+------+ In the first *Note `SELECT': select. statement, column `j' appears in both tables and thus becomes a join column, so, according to standard SQL, it should appear only once in the output, not twice. Similarly, in the second SELECT statement, column `j' is named in the `USING' clause and should appear only once in the output, not twice. But in both cases, the redundant column is not eliminated. Also, the order of the columns is not correct according to standard SQL. Now the statements produce this output: +------+------+------+ | j | i | k | +------+------+------+ | 1 | 1 | 1 | +------+------+------+ +------+------+------+ | j | i | k | +------+------+------+ | 1 | 1 | 1 | +------+------+------+ The redundant column is eliminated and the column order is correct according to standard SQL: * First, coalesced common columns of the two joined tables, in the order in which they occur in the first table * Second, columns unique to the first table, in order in which they occur in that table * Third, columns unique to the second table, in order in which they occur in that table The single result column that replaces two common columns is defined using the coalesce operation. That is, for two `t1.a' and `t2.a' the resulting single join column `a' is defined as `a = COALESCE(t1.a, t2.a)', where: COALESCE(x, y) = (CASE WHEN V1 IS NOT NULL THEN V1 ELSE V2 END) If the join operation is any other join, the result columns of the join consists of the concatenation of all columns of the joined tables. This is the same as previously. A consequence of the definition of coalesced columns is that, for outer joins, the coalesced column contains the value of the non-`NULL' column if one of the two columns is always `NULL'. If neither or both columns are `NULL', both common columns have the same value, so it doesn't matter which one is chosen as the value of the coalesced column. A simple way to interpret this is to consider that a coalesced column of an outer join is represented by the common column of the inner table of a `JOIN'. Suppose that the tables `t1(a,b)' and `t2(a,c)' have the following contents: t1 t2 ---- ---- 1 x 2 z 2 y 3 w Then: mysql> SELECT * FROM t1 NATURAL LEFT JOIN t2; +------+------+------+ | a | b | c | +------+------+------+ | 1 | x | NULL | | 2 | y | z | +------+------+------+ Here column `a' contains the values of `t1.a'. mysql> SELECT * FROM t1 NATURAL RIGHT JOIN t2; +------+------+------+ | a | c | b | +------+------+------+ | 2 | z | y | | 3 | w | NULL | +------+------+------+ Here column `a' contains the values of `t2.a'. Compare these results to the otherwise equivalent queries with `JOIN ... ON': mysql> SELECT * FROM t1 LEFT JOIN t2 ON (t1.a = t2.a); +------+------+------+------+ | a | b | a | c | +------+------+------+------+ | 1 | x | NULL | NULL | | 2 | y | 2 | z | +------+------+------+------+ mysql> SELECT * FROM t1 RIGHT JOIN t2 ON (t1.a = t2.a); +------+------+------+------+ | a | b | a | c | +------+------+------+------+ | 2 | y | 2 | z | | NULL | NULL | 3 | w | +------+------+------+------+ * Previously, a `USING' clause could be rewritten as an `ON' clause that compares corresponding columns. For example, the following two clauses were semantically identical: a LEFT JOIN b USING (c1,c2,c3) a LEFT JOIN b ON a.c1=b.c1 AND a.c2=b.c2 AND a.c3=b.c3 Now the two clauses no longer are quite the same: * With respect to determining which rows satisfy the join condition, both joins remain semantically identical. * With respect to determining which columns to display for `SELECT *' expansion, the two joins are not semantically identical. The `USING' join selects the coalesced value of corresponding columns, whereas the `ON' join selects all columns from all tables. For the preceding `USING' join, `SELECT *' selects these values: COALESCE(a.c1,b.c1), COALESCE(a.c2,b.c2), COALESCE(a.c3,b.c3) For the `ON' join, `SELECT *' selects these values: a.c1, a.c2, a.c3, b.c1, b.c2, b.c3 With an inner join, `COALESCE(a.c1,b.c1)' is the same as either `a.c1' or `b.c1' because both columns will have the same value. With an outer join (such as `LEFT JOIN'), one of the two columns can be `NULL'. That column will be omitted from the result. * The evaluation of multi-way natural joins differs in a very important way that affects the result of `NATURAL' or `USING' joins and that can require query rewriting. Suppose that you have three tables `t1(a,b)', `t2(c,b)', and `t3(a,c)' that each have one row: `t1(1,2)', `t2(10,2)', and `t3(7,10)'. Suppose also that you have this `NATURAL JOIN' on the three tables: SELECT ... FROM t1 NATURAL JOIN t2 NATURAL JOIN t3; Previously, the left operand of the second join was considered to be `t2', whereas it should be the nested join `(t1 NATURAL JOIN t2)'. As a result, the columns of `t3' are checked for common columns only in `t2', and, if `t3' has common columns with `t1', these columns are not used as equi-join columns. Thus, previously, the preceding query was transformed to the following equi-join: SELECT ... FROM t1, t2, t3 WHERE t1.b = t2.b AND t2.c = t3.c; That join is missing one more equi-join predicate `(t1.a = t3.a)'. As a result, it produces one row, not the empty result that it should. The correct equivalent query is this: SELECT ... FROM t1, t2, t3 WHERE t1.b = t2.b AND t2.c = t3.c AND t1.a = t3.a; If you require the same query result in current versions of MySQL as in older versions, rewrite the natural join as the first equi-join. * Previously, the comma operator (`,') and `JOIN' both had the same precedence, so the join expression `t1, t2 JOIN t3' was interpreted as `((t1, t2) JOIN t3)'. Now `JOIN' has higher precedence, so the expression is interpreted as `(t1, (t2 JOIN t3))'. This change affects statements that use an `ON' clause, because that clause can refer only to columns in the operands of the join, and the change in precedence changes interpretation of what those operands are. Example: CREATE TABLE t1 (i1 INT, j1 INT); CREATE TABLE t2 (i2 INT, j2 INT); CREATE TABLE t3 (i3 INT, j3 INT); INSERT INTO t1 VALUES(1,1); INSERT INTO t2 VALUES(1,1); INSERT INTO t3 VALUES(1,1); SELECT * FROM t1, t2 JOIN t3 ON (t1.i1 = t3.i3); Previously, the *Note `SELECT': select. was legal due to the implicit grouping of `t1,t2' as `(t1,t2)'. Now the `JOIN' takes precedence, so the operands for the `ON' clause are `t2' and `t3'. Because `t1.i1' is not a column in either of the operands, the result is an `Unknown column 't1.i1' in 'on clause'' error. To allow the join to be processed, group the first two tables explicitly with parentheses so that the operands for the `ON' clause are `(t1,t2)' and `t3': SELECT * FROM (t1, t2) JOIN t3 ON (t1.i1 = t3.i3); Alternatively, avoid the use of the comma operator and use `JOIN' instead: SELECT * FROM t1 JOIN t2 JOIN t3 ON (t1.i1 = t3.i3); This change also applies to statements that mix the comma operator with `INNER JOIN', `CROSS JOIN', `LEFT JOIN', and `RIGHT JOIN', all of which now have higher precedence than the comma operator. * Previously, the `ON' clause could refer to columns in tables named to its right. Now an `ON' clause can refer only to its operands. Example: CREATE TABLE t1 (i1 INT); CREATE TABLE t2 (i2 INT); CREATE TABLE t3 (i3 INT); SELECT * FROM t1 JOIN t2 ON (i1 = i3) JOIN t3; Previously, the *Note `SELECT': select. statement was legal. Now the statement fails with an `Unknown column 'i3' in 'on clause'' error because `i3' is a column in `t3', which is not an operand of the `ON' clause. The statement should be rewritten as follows: SELECT * FROM t1 JOIN t2 JOIN t3 ON (i1 = i3); * Resolution of column names in `NATURAL' or `USING' joins is different than previously. For column names that are outside the `FROM' clause, MySQL now handles a superset of the queries compared to previously. That is, in cases when MySQL formerly issued an error that some column is ambiguous, the query now is handled correctly. This is due to the fact that MySQL now treats the common columns of `NATURAL' or `USING' joins as a single column, so when a query refers to such columns, the query compiler does not consider them as ambiguous. Example: SELECT * FROM t1 NATURAL JOIN t2 WHERE b > 1; Previously, this query would produce an error `ERROR 1052 (23000): Column 'b' in where clause is ambiguous'. Now the query produces the correct result: +------+------+------+ | b | c | y | +------+------+------+ | 4 | 2 | 3 | +------+------+------+ One extension of MySQL compared to the SQL:2003 standard is that MySQL enables you to qualify the common (coalesced) columns of `NATURAL' or `USING' joins (just as previously), while the standard disallows that.  File: manual.info, Node: index-hints, Next: union, Prev: join, Up: select 13.2.8.2 Index Hint Syntax .......................... You can provide hints to give the optimizer information about how to choose indexes during query processing. *Note join::, describes the general syntax for specifying tables in a *Note `SELECT': select. statement. The syntax for an individual table, including that for index hints, looks like this: TBL_NAME [[AS] ALIAS] [INDEX_HINT_LIST] INDEX_HINT_LIST: INDEX_HINT [, INDEX_HINT] ... INDEX_HINT: USE {INDEX|KEY} [{FOR {JOIN|ORDER BY|GROUP BY}] ([INDEX_LIST]) | IGNORE {INDEX|KEY} [{FOR {JOIN|ORDER BY|GROUP BY}] (INDEX_LIST) | FORCE {INDEX|KEY} [{FOR {JOIN|ORDER BY|GROUP BY}] (INDEX_LIST) INDEX_LIST: INDEX_NAME [, INDEX_NAME] ... By specifying `USE INDEX (INDEX_LIST)', you can tell MySQL to use only one of the named indexes to find rows in the table. The alternative syntax `IGNORE INDEX (INDEX_LIST)' can be used to tell MySQL to not use some particular index or indexes. These hints are useful if *Note `EXPLAIN': explain. shows that MySQL is using the wrong index from the list of possible indexes. You can also use `FORCE INDEX', which acts like `USE INDEX (INDEX_LIST)' but with the addition that a table scan is assumed to be _very_ expensive. In other words, a table scan is used only if there is no way to use one of the given indexes to find rows in the table. Each hint requires the names of _indexes_, not the names of columns. The name of a `PRIMARY KEY' is `PRIMARY'. To see the index names for a table, use *Note `SHOW INDEX': show-index. An INDEX_NAME value need not be a full index name. It can be an unambiguous prefix of an index name. If a prefix is ambiguous, an error occurs. Prior to MySQL 5.1.17, `USE INDEX', `IGNORE INDEX', and `FORCE INDEX' affect only which indexes are used when MySQL decides how to find rows in the table and how to process joins. They do not affect whether an index is used when resolving an `ORDER BY' or `GROUP BY' clause. Examples: SELECT * FROM table1 USE INDEX (col1_index,col2_index) WHERE col1=1 AND col2=2 AND col3=3; SELECT * FROM table1 IGNORE INDEX (col3_index) WHERE col1=1 AND col2=2 AND col3=3; As of MySQL 5.1.17, the syntax for index hints is extended in the following ways: * It is syntactically valid to specify an empty INDEX_LIST for `USE INDEX', which means `use no indexes.' Specifying an empty INDEX_LIST for `FORCE INDEX' or `IGNORE INDEX' is a syntax error. * You can specify the scope of a index hint by adding a `FOR' clause to the hint. This provides more fine-grained control over the optimizer's selection of an execution plan for various phases of query processing. To affect only the indexes used when MySQL decides how to find rows in the table and how to process joins, use `FOR JOIN'. To influence index usage for sorting or grouping rows, use `FOR ORDER BY' or `FOR GROUP BY'. (However, if there is a covering index for the table and it is used to access the table, the optimizer will ignore `IGNORE INDEX FOR {ORDER BY|GROUP BY}' hints that disable that index.) * You can specify multiple index hints: SELECT * FROM t1 USE INDEX (i1) IGNORE INDEX FOR ORDER BY (i2) ORDER BY a; It is not a error to name the same index in several hints (even within the same hint): SELECT * FROM t1 USE INDEX (i1) USE INDEX (i1,i1); However, it is an error to mix `USE INDEX' and `FORCE INDEX' for the same table: SELECT * FROM t1 USE INDEX FOR JOIN (i1) FORCE INDEX FOR JOIN (i2); The default scope of index hints also is changed as of MySQL 5.1.17. Formerly, index hints applied only to how indexes are used for retrieval of records and not during resolution of `ORDER BY' or `GROUP BY' clauses. As of 5.1.17, if you specify no `FOR' clause for an index hint, the hint by default applies to all parts of the statement. For example, this hint: IGNORE INDEX (i1) is equivalent to this combination of hints: IGNORE INDEX FOR JOIN (i1) IGNORE INDEX FOR ORDER BY (i1) IGNORE INDEX FOR GROUP BY (i1) To cause the server to use the older behavior for hint scope when no `FOR' clause is present (so that hints apply only to row retrieval), enable the `old' system variable at server startup. Take care about enabling this variable in a replication setup. With statement-based binary logging, having different modes for the master and slaves might lead to replication errors. When index hints are processed, they are collected in a single list by type (*Note `USE': use, `FORCE', `IGNORE') and by scope (`FOR JOIN', `FOR ORDER BY', `FOR GROUP BY'). For example: SELECT * FROM t1 USE INDEX () IGNORE INDEX (i2) USE INDEX (i1) USE INDEX (i2); is equivalent to: SELECT * FROM t1 USE INDEX (i1,i2) IGNORE INDEX (i2); The index hints then are applied for each scope in the following order: 1. `{USE|FORCE} INDEX' is applied if present. (If not, the optimizer-determined set of indexes is used.) 2. `IGNORE INDEX' is applied over the result of the previous step. For example, the following two queries are equivalent: SELECT * FROM t1 USE INDEX (i1) IGNORE INDEX (i2) USE INDEX (i2); SELECT * FROM t1 USE INDEX (i1); For `FULLTEXT' searches, index hints do not work before MySQL 5.1.31. As of 5.1.31, index hints work as follows: * For natural language mode searches, index hints are silently ignored. For example, `IGNORE INDEX(i)' is ignored with no warning and the index is still used. For boolean mode searches, index hints with `FOR ORDER BY' or `FOR GROUP BY' are silently ignored. Index hints with `FOR JOIN' or no `FOR' modifier are honored. In contrast to how hints apply for non-`FULLTEXT' searches, the hint is used for all phases of query execution (finding rows and retrieval, grouping, and ordering). This is true even if the hint is given for a non-`FULLTEXT' index. For example, the following two queries are equivalent: SELECT * FROM t USE INDEX (index1) IGNORE INDEX (index1) FOR ORDER BY IGNORE INDEX (index1) FOR GROUP BY WHERE ... IN BOOLEAN MODE ... ; SELECT * FROM t USE INDEX (index1) WHERE ... IN BOOLEAN MODE ... ; Index hints are accepted but ignored for *Note `UPDATE': update. statements.  File: manual.info, Node: union, Prev: index-hints, Up: select 13.2.8.3 `UNION' Syntax ....................... SELECT ... UNION [ALL | DISTINCT] SELECT ... [UNION [ALL | DISTINCT] SELECT ...] *Note `UNION': union. is used to combine the result from multiple *Note `SELECT': select. statements into a single result set. The column names from the first *Note `SELECT': select. statement are used as the column names for the results returned. Selected columns listed in corresponding positions of each *Note `SELECT': select. statement should have the same data type. (For example, the first column selected by the first statement should have the same type as the first column selected by the other statements.) If the data types of corresponding *Note `SELECT': select. columns do not match, the types and lengths of the columns in the *Note `UNION': union. result take into account the values retrieved by all of the *Note `SELECT': select. statements. For example, consider the following: mysql> SELECT REPEAT('a',1) UNION SELECT REPEAT('b',10); +---------------+ | REPEAT('a',1) | +---------------+ | a | | bbbbbbbbbb | +---------------+ (In some earlier versions of MySQL, only the type and length from the first *Note `SELECT': select. would have been used and the second row would have been truncated to a length of 1.) The *Note `SELECT': select. statements are normal select statements, but with the following restrictions: * Only the last *Note `SELECT': select. statement can use `INTO OUTFILE'. (However, the entire *Note `UNION': union. result is written to the file.) * `HIGH_PRIORITY' cannot be used with *Note `SELECT': select. statements that are part of a *Note `UNION': union. If you specify it for the first *Note `SELECT': select, it has no effect. If you specify it for any subsequent *Note `SELECT': select. statements, a syntax error results. The default behavior for *Note `UNION': union. is that duplicate rows are removed from the result. The optional `DISTINCT' keyword has no effect other than the default because it also specifies duplicate-row removal. With the optional `ALL' keyword, duplicate-row removal does not occur and the result includes all matching rows from all the *Note `SELECT': select. statements. You can mix *Note `UNION ALL': union. and *Note `UNION DISTINCT': union. in the same query. Mixed *Note `UNION': union. types are treated such that a `DISTINCT' union overrides any `ALL' union to its left. A `DISTINCT' union can be produced explicitly by using *Note `UNION DISTINCT': union. or implicitly by using *Note `UNION': union. with no following `DISTINCT' or `ALL' keyword. To apply `ORDER BY' or `LIMIT' to an individual *Note `SELECT': select, place the clause inside the parentheses that enclose the *Note `SELECT': select.: (SELECT a FROM t1 WHERE a=10 AND B=1 ORDER BY a LIMIT 10) UNION (SELECT a FROM t2 WHERE a=11 AND B=2 ORDER BY a LIMIT 10); However, use of `ORDER BY' for individual *Note `SELECT': select. statements implies nothing about the order in which the rows appear in the final result because *Note `UNION': union. by default produces an unordered set of rows. Therefore, the use of `ORDER BY' in this context is typically in conjunction with `LIMIT', so that it is used to determine the subset of the selected rows to retrieve for the *Note `SELECT': select, even though it does not necessarily affect the order of those rows in the final *Note `UNION': union. result. If `ORDER BY' appears without `LIMIT' in a *Note `SELECT': select, it is optimized away because it will have no effect anyway. To use an `ORDER BY' or `LIMIT' clause to sort or limit the entire *Note `UNION': union. result, parenthesize the individual *Note `SELECT': select. statements and place the `ORDER BY' or `LIMIT' after the last one. The following example uses both clauses: (SELECT a FROM t1 WHERE a=10 AND B=1) UNION (SELECT a FROM t2 WHERE a=11 AND B=2) ORDER BY a LIMIT 10; A statement without parentheses is equivalent to one parenthesized as just shown. This kind of `ORDER BY' cannot use column references that include a table name (that is, names in TBL_NAME.COL_NAME format). Instead, provide a column alias in the first *Note `SELECT': select. statement and refer to the alias in the `ORDER BY'. (Alternatively, refer to the column in the `ORDER BY' using its column position. However, use of column positions is deprecated.) Also, if a column to be sorted is aliased, the `ORDER BY' clause _must_ refer to the alias, not the column name. The first of the following statements will work, but the second will fail with an `Unknown column 'a' in 'order clause'' error: (SELECT a AS b FROM t) UNION (SELECT ...) ORDER BY b; (SELECT a AS b FROM t) UNION (SELECT ...) ORDER BY a; To cause rows in a *Note `UNION': union. result to consist of the sets of rows retrieved by each *Note `SELECT': select. one after the other, select an additional column in each *Note `SELECT': select. to use as a sort column and add an `ORDER BY' following the last *Note `SELECT': select.: (SELECT 1 AS sort_col, col1a, col1b, ... FROM t1) UNION (SELECT 2, col2a, col2b, ... FROM t2) ORDER BY sort_col; To additionally maintain sort order within individual *Note `SELECT': select. results, add a secondary column to the `ORDER BY' clause: (SELECT 1 AS sort_col, col1a, col1b, ... FROM t1) UNION (SELECT 2, col2a, col2b, ... FROM t2) ORDER BY sort_col, col1a; Use of an additional column also enables you to determine which *Note `SELECT': select. each row comes from. Extra columns can provide other identifying information as well, such as a string that indicates a table name.  File: manual.info, Node: subqueries, Next: update, Prev: select, Up: sql-syntax-data-manipulation 13.2.9 Subquery Syntax ---------------------- * Menu: * scalar-subqueries:: The Subquery as Scalar Operand * comparisons-using-subqueries:: Comparisons Using Subqueries * any-in-some-subqueries:: Subqueries with `ANY', `IN', or `SOME' * all-subqueries:: Subqueries with `ALL' * row-subqueries:: Row Subqueries * exists-and-not-exists-subqueries:: Subqueries with `EXISTS' or `NOT EXISTS' * correlated-subqueries:: Correlated Subqueries * from-clause-subqueries:: Subqueries in the `FROM' Clause * subquery-errors:: Subquery Errors * optimizing-subqueries:: Optimizing Subqueries * rewriting-subqueries:: Rewriting Subqueries as Joins A subquery is a *Note `SELECT': select. statement within another statement. Starting with MySQL 4.1, all subquery forms and operations that the SQL standard requires are supported, as well as a few features that are MySQL-specific. Here is an example of a subquery: SELECT * FROM t1 WHERE column1 = (SELECT column1 FROM t2); In this example, `SELECT * FROM t1 ...' is the _outer query_ (or _outer statement_), and `(SELECT column1 FROM t2)' is the _subquery_. We say that the subquery is _nested_ within the outer query, and in fact it is possible to nest subqueries within other subqueries, to a considerable depth. A subquery must always appear within parentheses. The main advantages of subqueries are: * They allow queries that are _structured_ so that it is possible to isolate each part of a statement. * They provide alternative ways to perform operations that would otherwise require complex joins and unions. * Many people find subqueries more readable than complex joins or unions. Indeed, it was the innovation of subqueries that gave people the original idea of calling the early SQL `Structured Query Language.' Here is an example statement that shows the major points about subquery syntax as specified by the SQL standard and supported in MySQL: DELETE FROM t1 WHERE s11 > ANY (SELECT COUNT(*) /* no hint */ FROM t2 WHERE NOT EXISTS (SELECT * FROM t3 WHERE ROW(5*t2.s1,77)= (SELECT 50,11*s1 FROM t4 UNION SELECT 50,77 FROM (SELECT * FROM t5) AS t5))); A subquery can return a scalar (a single value), a single row, a single column, or a table (one or more rows of one or more columns). These are called scalar, column, row, and table subqueries. Subqueries that return a particular kind of result often can be used only in certain contexts, as described in the following sections. There are few restrictions on the type of statements in which subqueries can be used. A subquery can contain many of the keywords or clauses that an ordinary *Note `SELECT': select. can contain: `DISTINCT', `GROUP BY', `ORDER BY', `LIMIT', joins, index hints, *Note `UNION': union. constructs, comments, functions, and so on. One restriction is that a subquery's outer statement must be one of: *Note `SELECT': select, *Note `INSERT': insert, *Note `UPDATE': update, *Note `DELETE': delete, *Note `SET': set-option, or *Note `DO': do. Another restriction is that currently you cannot modify a table and select from the same table in a subquery. This applies to statements such as *Note `DELETE': delete, *Note `INSERT': insert, *Note `REPLACE': replace, *Note `UPDATE': update, and (because subqueries can be used in the `SET' clause) *Note `LOAD DATA INFILE': load-data. A more comprehensive discussion of restrictions on subquery use, including performance issues for certain forms of subquery syntax, is given in *Note subquery-restrictions::.  File: manual.info, Node: scalar-subqueries, Next: comparisons-using-subqueries, Prev: subqueries, Up: subqueries 13.2.9.1 The Subquery as Scalar Operand ....................................... In its simplest form, a subquery is a scalar subquery that returns a single value. A scalar subquery is a simple operand, and you can use it almost anywhere a single column value or literal is legal, and you can expect it to have those characteristics that all operands have: a data type, a length, an indication that it can be `NULL', and so on. For example: CREATE TABLE t1 (s1 INT, s2 CHAR(5) NOT NULL); INSERT INTO t1 VALUES(100, 'abcde'); SELECT (SELECT s2 FROM t1); The subquery in this *Note `SELECT': select. returns a single value (`'abcde'') that has a data type of *Note `CHAR': char, a length of 5, a character set and collation equal to the defaults in effect at *Note `CREATE TABLE': create-table. time, and an indication that the value in the column can be `NULL'. Nullability of the value selected by a scalar subquery is not copied because if the subquery result is empty, the result is `NULL'. For the subquery just shown, if `t1' were empty, the result would be `NULL' even though `s2' is `NOT NULL'. There are a few contexts in which a scalar subquery cannot be used. If a statement permits only a literal value, you cannot use a subquery. For example, `LIMIT' requires literal integer arguments, and *Note `LOAD DATA INFILE': load-data. requires a literal string file name. You cannot use subqueries to supply these values. When you see examples in the following sections that contain the rather spartan construct `(SELECT column1 FROM t1)', imagine that your own code contains much more diverse and complex constructions. Suppose that we make two tables: CREATE TABLE t1 (s1 INT); INSERT INTO t1 VALUES (1); CREATE TABLE t2 (s1 INT); INSERT INTO t2 VALUES (2); Then perform a *Note `SELECT': select.: SELECT (SELECT s1 FROM t2) FROM t1; The result is `2' because there is a row in `t2' containing a column `s1' that has a value of `2'. A scalar subquery can be part of an expression, but remember the parentheses, even if the subquery is an operand that provides an argument for a function. For example: SELECT UPPER((SELECT s1 FROM t1)) FROM t2;  File: manual.info, Node: comparisons-using-subqueries, Next: any-in-some-subqueries, Prev: scalar-subqueries, Up: subqueries 13.2.9.2 Comparisons Using Subqueries ..................................... The most common use of a subquery is in the form: NON_SUBQUERY_OPERAND COMPARISON_OPERATOR (SUBQUERY) Where COMPARISON_OPERATOR is one of these operators: = > < >= <= <> != <=> For example: ... WHERE 'a' = (SELECT column1 FROM t1) MySQL also permits this construct: NON_SUBQUERY_OPERAND LIKE (SUBQUERY) At one time the only legal place for a subquery was on the right side of a comparison, and you might still find some old DBMSs that insist on this. Here is an example of a common-form subquery comparison that you cannot do with a join. It finds all the rows in table `t1' for which the `column1' value is equal to a maximum value in table `t2': SELECT * FROM t1 WHERE column1 = (SELECT MAX(column2) FROM t2); Here is another example, which again is impossible with a join because it involves aggregating for one of the tables. It finds all rows in table `t1' containing a value that occurs twice in a given column: SELECT * FROM t1 AS t WHERE 2 = (SELECT COUNT(*) FROM t1 WHERE t1.id = t.id); For a comparison of the subquery to a scalar, the subquery must return a scalar. For a comparison of the subquery to a row constructor, the subquery must be a row subquery that returns a row with the same number of values as the row constructor. See *Note row-subqueries::.  File: manual.info, Node: any-in-some-subqueries, Next: all-subqueries, Prev: comparisons-using-subqueries, Up: subqueries 13.2.9.3 Subqueries with `ANY', `IN', or `SOME' ............................................... Syntax: OPERAND COMPARISON_OPERATOR ANY (SUBQUERY) OPERAND IN (SUBQUERY) OPERAND COMPARISON_OPERATOR SOME (SUBQUERY) Where COMPARISON_OPERATOR is one of these operators: = > < >= <= <> != The `ANY' keyword, which must follow a comparison operator, means `return `TRUE' if the comparison is `TRUE' for `ANY' of the values in the column that the subquery returns.' For example: SELECT s1 FROM t1 WHERE s1 > ANY (SELECT s1 FROM t2); Suppose that there is a row in table `t1' containing `(10)'. The expression is `TRUE' if table `t2' contains `(21,14,7)' because there is a value `7' in `t2' that is less than `10'. The expression is `FALSE' if table `t2' contains `(20,10)', or if table `t2' is empty. The expression is _unknown_ (that is, `NULL') if table `t2' contains `(NULL,NULL,NULL)'. When used with a subquery, the word `IN' is an alias for `= ANY'. Thus, these two statements are the same: SELECT s1 FROM t1 WHERE s1 = ANY (SELECT s1 FROM t2); SELECT s1 FROM t1 WHERE s1 IN (SELECT s1 FROM t2); `IN' and `= ANY' are not synonyms when used with an expression list. `IN' can take an expression list, but `= ANY' cannot. See *Note comparison-operators::. `NOT IN' is not an alias for `<> ANY', but for `<> ALL'. See *Note all-subqueries::. The word `SOME' is an alias for `ANY'. Thus, these two statements are the same: SELECT s1 FROM t1 WHERE s1 <> ANY (SELECT s1 FROM t2); SELECT s1 FROM t1 WHERE s1 <> SOME (SELECT s1 FROM t2); Use of the word `SOME' is rare, but this example shows why it might be useful. To most people, the English phrase `a is not equal to any b' means `there is no b which is equal to a,' but that is not what is meant by the SQL syntax. The syntax means `there is some b to which a is not equal.' Using `<> SOME' instead helps ensure that everyone understands the true meaning of the query.  File: manual.info, Node: all-subqueries, Next: row-subqueries, Prev: any-in-some-subqueries, Up: subqueries 13.2.9.4 Subqueries with `ALL' .............................. Syntax: OPERAND COMPARISON_OPERATOR ALL (SUBQUERY) The word `ALL', which must follow a comparison operator, means `return `TRUE' if the comparison is `TRUE' for `ALL' of the values in the column that the subquery returns.' For example: SELECT s1 FROM t1 WHERE s1 > ALL (SELECT s1 FROM t2); Suppose that there is a row in table `t1' containing `(10)'. The expression is `TRUE' if table `t2' contains `(-5,0,+5)' because `10' is greater than all three values in `t2'. The expression is `FALSE' if table `t2' contains `(12,6,NULL,-100)' because there is a single value `12' in table `t2' that is greater than `10'. The expression is _unknown_ (that is, `NULL') if table `t2' contains `(0,NULL,1)'. Finally, the expression is `TRUE' if table `t2' is empty. So, the following expression is `TRUE' when table `t2' is empty: SELECT * FROM t1 WHERE 1 > ALL (SELECT s1 FROM t2); But this expression is `NULL' when table `t2' is empty: SELECT * FROM t1 WHERE 1 > (SELECT s1 FROM t2); In addition, the following expression is `NULL' when table `t2' is empty: SELECT * FROM t1 WHERE 1 > ALL (SELECT MAX(s1) FROM t2); In general, _tables containing `NULL' values_ and _empty tables_ are `edge cases.' When writing subqueries, always consider whether you have taken those two possibilities into account. `NOT IN' is an alias for `<> ALL'. Thus, these two statements are the same: SELECT s1 FROM t1 WHERE s1 <> ALL (SELECT s1 FROM t2); SELECT s1 FROM t1 WHERE s1 NOT IN (SELECT s1 FROM t2);  File: manual.info, Node: row-subqueries, Next: exists-and-not-exists-subqueries, Prev: all-subqueries, Up: subqueries 13.2.9.5 Row Subqueries ....................... The discussion to this point has been of scalar or column subqueries; that is, subqueries that return a single value or a column of values. A _row subquery_ is a subquery variant that returns a single row and can thus return more than one column value. Legal operators for row subquery comparisons are: = > < >= <= <> != <=> Here are two examples: SELECT * FROM t1 WHERE (col1,col2) = (SELECT col3, col4 FROM t2 WHERE id = 10); SELECT * FROM t1 WHERE ROW(col1,col2) = (SELECT col3, col4 FROM t2 WHERE id = 10); For both queries, if the table `t2' contains a single row with `id = 10', the subquery returns a single row. If this row has `col3' and `col4' values equal to the `col1' and `col2' values of any rows in `t1', the `WHERE' expression is `TRUE' and each query returns those `t1' rows. If the `t2' row `col3' and `col4' values are not equal the `col1' and `col2' values of any `t1' row, the expression is `FALSE' and the query returns an empty result set. The expression is _unknown_ (that is, `NULL') if the subquery produces no rows. An error occurs if the subquery produces multiple rows because a row subquery can return at most one row. The expressions `(1,2)' and `ROW(1,2)' are sometimes called _row constructors_. The two are equivalent. The row constructor and the row returned by the subquery must contain the same number of values. A row constructor is used for comparisons with subqueries that return two or more columns. When a subquery returns a single column, this is regarded as a scalar value and not as a row, so a row constructor cannot be used with a subquery that does not return at least two columns. Thus, the following query fails with a syntax error: SELECT * FROM t1 WHERE ROW(1) = (SELECT column1 FROM t2) Row constructors are legal in other contexts. For example, the following two statements are semantically equivalent: SELECT * FROM t1 WHERE (column1,column2) = (1,1); SELECT * FROM t1 WHERE column1 = 1 AND column2 = 1; Prior to MySQL 5.1.12, only the second of the preceding two expressions could be optimized. The following query answers the request, `find all rows in table `t1' that also exist in table `t2'': SELECT column1,column2,column3 FROM t1 WHERE (column1,column2,column3) IN (SELECT column1,column2,column3 FROM t2);  File: manual.info, Node: exists-and-not-exists-subqueries, Next: correlated-subqueries, Prev: row-subqueries, Up: subqueries 13.2.9.6 Subqueries with `EXISTS' or `NOT EXISTS' ................................................. If a subquery returns any rows at all, `EXISTS SUBQUERY' is `TRUE', and `NOT EXISTS SUBQUERY' is `FALSE'. For example: SELECT column1 FROM t1 WHERE EXISTS (SELECT * FROM t2); Traditionally, an `EXISTS' subquery starts with `SELECT *', but it could begin with `SELECT 5' or `SELECT column1' or anything at all. MySQL ignores the *Note `SELECT': select. list in such a subquery, so it makes no difference. For the preceding example, if `t2' contains any rows, even rows with nothing but `NULL' values, the `EXISTS' condition is `TRUE'. This is actually an unlikely example because a `[NOT] EXISTS' subquery almost always contains correlations. Here are some more realistic examples: * What kind of store is present in one or more cities? SELECT DISTINCT store_type FROM stores WHERE EXISTS (SELECT * FROM cities_stores WHERE cities_stores.store_type = stores.store_type); * What kind of store is present in no cities? SELECT DISTINCT store_type FROM stores WHERE NOT EXISTS (SELECT * FROM cities_stores WHERE cities_stores.store_type = stores.store_type); * What kind of store is present in all cities? SELECT DISTINCT store_type FROM stores s1 WHERE NOT EXISTS ( SELECT * FROM cities WHERE NOT EXISTS ( SELECT * FROM cities_stores WHERE cities_stores.city = cities.city AND cities_stores.store_type = stores.store_type)); The last example is a double-nested `NOT EXISTS' query. That is, it has a `NOT EXISTS' clause within a `NOT EXISTS' clause. Formally, it answers the question `does a city exist with a store that is not in `Stores''? But it is easier to say that a nested `NOT EXISTS' answers the question `is X `TRUE' for all Y?'  File: manual.info, Node: correlated-subqueries, Next: from-clause-subqueries, Prev: exists-and-not-exists-subqueries, Up: subqueries 13.2.9.7 Correlated Subqueries .............................. A _correlated subquery_ is a subquery that contains a reference to a table that also appears in the outer query. For example: SELECT * FROM t1 WHERE column1 = ANY (SELECT column1 FROM t2 WHERE t2.column2 = t1.column2); Notice that the subquery contains a reference to a column of `t1', even though the subquery's `FROM' clause does not mention a table `t1'. So, MySQL looks outside the subquery, and finds `t1' in the outer query. Suppose that table `t1' contains a row where `column1 = 5' and `column2 = 6'; meanwhile, table `t2' contains a row where `column1 = 5' and `column2 = 7'. The simple expression `... WHERE column1 = ANY (SELECT column1 FROM t2)' would be `TRUE', but in this example, the `WHERE' clause within the subquery is `FALSE' (because `(5,6)' is not equal to `(5,7)'), so the expression as a whole is `FALSE'. *Scoping rule:* MySQL evaluates from inside to outside. For example: SELECT column1 FROM t1 AS x WHERE x.column1 = (SELECT column1 FROM t2 AS x WHERE x.column1 = (SELECT column1 FROM t3 WHERE x.column2 = t3.column1)); In this statement, `x.column2' must be a column in table `t2' because `SELECT column1 FROM t2 AS x ...' renames `t2'. It is not a column in table `t1' because `SELECT column1 FROM t1 ...' is an outer query that is _farther out_. For subqueries in `HAVING' or `ORDER BY' clauses, MySQL also looks for column names in the outer select list. For certain cases, a correlated subquery is optimized. For example: VAL IN (SELECT KEY_VAL FROM TBL_NAME WHERE CORRELATED_CONDITION) Otherwise, they are inefficient and likely to be slow. Rewriting the query as a join might improve performance. Aggregate functions in correlated subqueries may contain outer references, provided the function contains nothing but outer references, and provided the function is not contained in another function or expression.  File: manual.info, Node: from-clause-subqueries, Next: subquery-errors, Prev: correlated-subqueries, Up: subqueries 13.2.9.8 Subqueries in the `FROM' Clause ........................................ Subqueries are legal in a *Note `SELECT': select. statement's `FROM' clause. The actual syntax is: SELECT ... FROM (SUBQUERY) [AS] NAME ... The `[AS] NAME' clause is mandatory, because every table in a `FROM' clause must have a name. Any columns in the SUBQUERY select list must have unique names. For the sake of illustration, assume that you have this table: CREATE TABLE t1 (s1 INT, s2 CHAR(5), s3 FLOAT); Here is how to use a subquery in the `FROM' clause, using the example table: INSERT INTO t1 VALUES (1,'1',1.0); INSERT INTO t1 VALUES (2,'2',2.0); SELECT sb1,sb2,sb3 FROM (SELECT s1 AS sb1, s2 AS sb2, s3*2 AS sb3 FROM t1) AS sb WHERE sb1 > 1; Result: `2, '2', 4.0'. Here is another example: Suppose that you want to know the average of a set of sums for a grouped table. This does not work: SELECT AVG(SUM(column1)) FROM t1 GROUP BY column1; However, this query provides the desired information: SELECT AVG(sum_column1) FROM (SELECT SUM(column1) AS sum_column1 FROM t1 GROUP BY column1) AS t1; Notice that the column name used within the subquery (`sum_column1') is recognized in the outer query. Subqueries in the `FROM' clause can return a scalar, column, row, or table. Subqueries in the `FROM' clause cannot be correlated subqueries, unless used within the `ON' clause of a `JOIN' operation. Subqueries in the `FROM' clause are executed even for the *Note `EXPLAIN': explain. statement (that is, derived temporary tables are built). This occurs because upper-level queries need information about all tables during the optimization phase, and the table represented by a subquery in the `FROM' clause is unavailable unless the subquery is executed. It is possible under certain circumstances to modify table data using *Note `EXPLAIN SELECT': explain. This can occur if the outer query accesses any tables and an inner query invokes a stored function that changes one or more rows of a table. Suppose that there are two tables `t1' and `t2' in database `d1', created as shown here: mysql> CREATE DATABASE d1; Query OK, 1 row affected (0.00 sec) mysql> USE d1; Database changed mysql> CREATE TABLE t1 (c1 INT); Query OK, 0 rows affected (0.15 sec) mysql> CREATE TABLE t2 (c1 INT); Query OK, 0 rows affected (0.08 sec) Now we create a stored function `f1' which modifies `t2': mysql> DELIMITER // mysql> CREATE FUNCTION f1(p1 INT) RETURNS INT mysql> BEGIN mysql> INSERT INTO t2 VALUES (p1); mysql> RETURN p1; mysql> END // Query OK, 0 rows affected (0.01 sec) mysql> DELIMITER ; Referencing the function directly in an *Note `EXPLAIN SELECT': explain. does not have any effect on `t2', as shown here: mysql> SELECT * FROM t2; Empty set (0.00 sec) mysql> EXPLAIN SELECT f1(5); +----+-------------+-------+------+---------------+------+---------+------+------+----------------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra | +----+-------------+-------+------+---------------+------+---------+------+------+----------------+ | 1 | SIMPLE | NULL | NULL | NULL | NULL | NULL | NULL | NULL | No tables used | +----+-------------+-------+------+---------------+------+---------+------+------+----------------+ 1 row in set (0.00 sec) mysql> SELECT * FROM t2; Empty set (0.00 sec) This is because the *Note `SELECT': select. statement did not reference any tables, as can be seen in the `table' and `Extra' columns of the output. This is also true of the following nested *Note `SELECT': select.: mysql> EXPLAIN SELECT NOW() AS a1, (SELECT f1(5)) AS a2; +----+-------------+-------+------+---------------+------+---------+------+------+----------------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra | +----+-------------+-------+------+---------------+------+---------+------+------+----------------+ | 1 | PRIMARY | NULL | NULL | NULL | NULL | NULL | NULL | NULL | No tables used | +----+-------------+-------+------+---------------+------+---------+------+------+----------------+ 1 row in set, 1 warning (0.00 sec) mysql> SHOW WARNINGS; +-------+------+------------------------------------------+ | Level | Code | Message | +-------+------+------------------------------------------+ | Note | 1249 | Select 2 was reduced during optimization | +-------+------+------------------------------------------+ 1 row in set (0.00 sec) mysql> SELECT * FROM t2; Empty set (0.00 sec) However, if the outer *Note `SELECT': select. references any tables, the optimizer executes the statement in the subquery as well: mysql> EXPLAIN SELECT * FROM t1 AS a1, (SELECT f1(5)) AS a2; +----+-------------+------------+--------+---------------+------+---------+------+------+---------------------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra | +----+-------------+------------+--------+---------------+------+---------+------+------+---------------------+ | 1 | PRIMARY | a1 | system | NULL | NULL | NULL | NULL | 0 | const row not found | | 1 | PRIMARY | | system | NULL | NULL | NULL | NULL | 1 | | | 2 | DERIVED | NULL | NULL | NULL | NULL | NULL | NULL | NULL | No tables used | +----+-------------+------------+--------+---------------+------+---------+------+------+---------------------+ 3 rows in set (0.00 sec) mysql> SELECT * FROM t2; +------+ | c1 | +------+ | 5 | +------+ 1 row in set (0.00 sec) This also means that an *Note `EXPLAIN SELECT': explain. statement such as the one shown here may take a long time to execute because the `BENCHMARK()' function is executed once for each row in `t1': EXPLAIN SELECT * FROM t1 AS a1, (SELECT BENCHMARK(1000000, MD5(NOW())));  File: manual.info, Node: subquery-errors, Next: optimizing-subqueries, Prev: from-clause-subqueries, Up: subqueries 13.2.9.9 Subquery Errors ........................ There are some errors that apply only to subqueries. This section describes them. * Unsupported subquery syntax: ERROR 1235 (ER_NOT_SUPPORTED_YET) SQLSTATE = 42000 Message = "This version of MySQL doesn't yet support 'LIMIT & IN/ALL/ANY/SOME subquery'" This means that MySQL does not support statements of the following form: SELECT * FROM t1 WHERE s1 IN (SELECT s2 FROM t2 ORDER BY s1 LIMIT 1) * Incorrect number of columns from subquery: ERROR 1241 (ER_OPERAND_COL) SQLSTATE = 21000 Message = "Operand should contain 1 column(s)" This error occurs in cases like this: SELECT (SELECT column1, column2 FROM t2) FROM t1; You may use a subquery that returns multiple columns, if the purpose is row comparison. In other contexts, the subquery must be a scalar operand. See *Note row-subqueries::. * Incorrect number of rows from subquery: ERROR 1242 (ER_SUBSELECT_NO_1_ROW) SQLSTATE = 21000 Message = "Subquery returns more than 1 row" This error occurs for statements where the subquery must return at most one row but returns multiple rows. Consider the following example: SELECT * FROM t1 WHERE column1 = (SELECT column1 FROM t2); If `SELECT column1 FROM t2' returns just one row, the previous query will work. If the subquery returns more than one row, error 1242 will occur. In that case, the query should be rewritten as: SELECT * FROM t1 WHERE column1 = ANY (SELECT column1 FROM t2); * Incorrectly used table in subquery: Error 1093 (ER_UPDATE_TABLE_USED) SQLSTATE = HY000 Message = "You can't specify target table 'x' for update in FROM clause" This error occurs in cases such as the following, which attempts to modify a table and select from the same table in the subquery: UPDATE t1 SET column2 = (SELECT MAX(column1) FROM t1); You can use a subquery for assignment within an *Note `UPDATE': update. statement because subqueries are legal in *Note `UPDATE': update. and *Note `DELETE': delete. statements as well as in *Note `SELECT': select. statements. However, you cannot use the same table (in this case, table `t1') for both the subquery `FROM' clause and the update target. For transactional storage engines, the failure of a subquery causes the entire statement to fail. For nontransactional storage engines, data modifications made before the error was encountered are preserved.  File: manual.info, Node: optimizing-subqueries, Next: rewriting-subqueries, Prev: subquery-errors, Up: subqueries 13.2.9.10 Optimizing Subqueries ............................... Development is ongoing, so no optimization tip is reliable for the long term. The following list provides some interesting tricks that you might want to play with: * Use subquery clauses that affect the number or order of the rows in the subquery. For example: SELECT * FROM t1 WHERE t1.column1 IN (SELECT column1 FROM t2 ORDER BY column1); SELECT * FROM t1 WHERE t1.column1 IN (SELECT DISTINCT column1 FROM t2); SELECT * FROM t1 WHERE EXISTS (SELECT * FROM t2 LIMIT 1); * Replace a join with a subquery. For example, try this: SELECT DISTINCT column1 FROM t1 WHERE t1.column1 IN ( SELECT column1 FROM t2); Instead of this: SELECT DISTINCT t1.column1 FROM t1, t2 WHERE t1.column1 = t2.column1; * Some subqueries can be transformed to joins for compatibility with older versions of MySQL that do not support subqueries. However, in some cases, converting a subquery to a join may improve performance. See *Note rewriting-subqueries::. * Move clauses from outside to inside the subquery. For example, use this query: SELECT * FROM t1 WHERE s1 IN (SELECT s1 FROM t1 UNION ALL SELECT s1 FROM t2); Instead of this query: SELECT * FROM t1 WHERE s1 IN (SELECT s1 FROM t1) OR s1 IN (SELECT s1 FROM t2); For another example, use this query: SELECT (SELECT column1 + 5 FROM t1) FROM t2; Instead of this query: SELECT (SELECT column1 FROM t1) + 5 FROM t2; * Use a row subquery instead of a correlated subquery. For example, use this query: SELECT * FROM t1 WHERE (column1,column2) IN (SELECT column1,column2 FROM t2); Instead of this query: SELECT * FROM t1 WHERE EXISTS (SELECT * FROM t2 WHERE t2.column1=t1.column1 AND t2.column2=t1.column2); * Use `NOT (a = ANY (...))' rather than `a <> ALL (...)'. * Use `x = ANY (TABLE CONTAINING (1,2))' rather than `x=1 OR x=2'. * Use `= ANY' rather than `EXISTS'. * For uncorrelated subqueries that always return one row, `IN' is always slower than `='. For example, use this query: SELECT * FROM t1 WHERE t1.COL_NAME = (SELECT a FROM t2 WHERE b = SOME_CONST); Instead of this query: SELECT * FROM t1 WHERE t1.COL_NAME IN (SELECT a FROM t2 WHERE b = SOME_CONST); These tricks might cause programs to go faster or slower. Using MySQL facilities like the `BENCHMARK()' function, you can get an idea about what helps in your own situation. See *Note information-functions::. Some optimizations that MySQL itself makes are: * MySQL executes uncorrelated subqueries only once. Use *Note `EXPLAIN': explain. to make sure that a given subquery really is uncorrelated. * MySQL rewrites `IN', `ALL', `ANY', and `SOME' subqueries in an attempt to take advantage of the possibility that the select-list columns in the subquery are indexed. * MySQL replaces subqueries of the following form with an index-lookup function, which *Note `EXPLAIN': explain. describes as a special join type (`unique_subquery' or `index_subquery'): ... IN (SELECT INDEXED_COLUMN FROM SINGLE_TABLE ...) * MySQL enhances expressions of the following form with an expression involving `MIN()' or `MAX()', unless `NULL' values or empty sets are involved: VALUE {ALL|ANY|SOME} {> | < | >= | <=} (UNCORRELATED SUBQUERY) For example, this `WHERE' clause: WHERE 5 > ALL (SELECT x FROM t) might be treated by the optimizer like this: WHERE 5 > (SELECT MAX(x) FROM t) See also the MySQL Internals Manual chapter How MySQL Transforms Subqueries (http://forge.mysql.com/wiki/MySQL_Internals_Transformations).  File: manual.info, Node: rewriting-subqueries, Prev: optimizing-subqueries, Up: subqueries 13.2.9.11 Rewriting Subqueries as Joins ....................................... Sometimes there are other ways to test membership in a set of values than by using a subquery. Also, on some occasions, it is not only possible to rewrite a query without a subquery, but it can be more efficient to make use of some of these techniques rather than to use subqueries. One of these is the `IN()' construct: For example, this query: SELECT * FROM t1 WHERE id IN (SELECT id FROM t2); Can be rewritten as: SELECT DISTINCT t1.* FROM t1, t2 WHERE t1.id=t2.id; The queries: SELECT * FROM t1 WHERE id NOT IN (SELECT id FROM t2); SELECT * FROM t1 WHERE NOT EXISTS (SELECT id FROM t2 WHERE t1.id=t2.id); Can be rewritten as: SELECT table1.* FROM table1 LEFT JOIN table2 ON table1.id=table2.id WHERE table2.id IS NULL; A `LEFT [OUTER] JOIN' can be faster than an equivalent subquery because the server might be able to optimize it better--a fact that is not specific to MySQL Server alone. Prior to SQL-92, outer joins did not exist, so subqueries were the only way to do certain things. Today, MySQL Server and many other modern database systems offer a wide range of outer join types. MySQL Server supports multiple-table *Note `DELETE': delete. statements that can be used to efficiently delete rows based on information from one table or even from many tables at the same time. Multiple-table *Note `UPDATE': update. statements are also supported. See *Note delete::, and *Note update::.  File: manual.info, Node: update, Prev: subqueries, Up: sql-syntax-data-manipulation 13.2.10 `UPDATE' Syntax ----------------------- Single-table syntax: UPDATE [LOW_PRIORITY] [IGNORE] TABLE_REFERENCE SET COL_NAME1={EXPR1|DEFAULT} [, COL_NAME2={EXPR2|DEFAULT}] ... [WHERE WHERE_CONDITION] [ORDER BY ...] [LIMIT ROW_COUNT] Multiple-table syntax: UPDATE [LOW_PRIORITY] [IGNORE] TABLE_REFERENCES SET COL_NAME1={EXPR1|DEFAULT} [, COL_NAME2={EXPR2|DEFAULT}] ... [WHERE WHERE_CONDITION] For the single-table syntax, the *Note `UPDATE': update. statement updates columns of existing rows in the named table with new values. The `SET' clause indicates which columns to modify and the values they should be given. Each value can be given as an expression, or the keyword `DEFAULT' to set a column explicitly to its default value. The `WHERE' clause, if given, specifies the conditions that identify which rows to update. With no `WHERE' clause, all rows are updated. If the `ORDER BY' clause is specified, the rows are updated in the order that is specified. The `LIMIT' clause places a limit on the number of rows that can be updated. For the multiple-table syntax, *Note `UPDATE': update. updates rows in each table named in TABLE_REFERENCES that satisfy the conditions. In this case, `ORDER BY' and `LIMIT' cannot be used. WHERE_CONDITION is an expression that evaluates to true for each row to be updated. For expression syntax, see *Note expressions::. TABLE_REFERENCES and WHERE_CONDITION are is specified as described in *Note select::. You need the `UPDATE' privilege only for columns referenced in an *Note `UPDATE': update. that are actually updated. You need only the `SELECT' privilege for any columns that are read but not modified. The *Note `UPDATE': update. statement supports the following modifiers: * With the `LOW_PRIORITY' keyword, execution of the *Note `UPDATE': update. is delayed until no other clients are reading from the table. This affects only storage engines that use only table-level locking (such as `MyISAM', `MEMORY', and `MERGE'). * With the `IGNORE' keyword, the update statement does not abort even if errors occur during the update. Rows for which duplicate-key conflicts occur are not updated. Rows for which columns are updated to values that would cause data conversion errors are updated to the closest valid values instead. If you access a column from the table to be updated in an expression, *Note `UPDATE': update. uses the current value of the column. For example, the following statement sets `col1' to one more than its current value: UPDATE t1 SET col1 = col1 + 1; The second assignment in the following statement sets `col2' to the current (updated) `col1' value, not the original `col1' value. The result is that `col1' and `col2' have the same value. This behavior differs from standard SQL. UPDATE t1 SET col1 = col1 + 1, col2 = col1; Single-table *Note `UPDATE': update. assignments are generally evaluated from left to right. For multiple-table updates, there is no guarantee that assignments are carried out in any particular order. If you set a column to the value it currently has, MySQL notices this and does not update it. If you update a column that has been declared `NOT NULL' by setting to `NULL', an error occurs if strict SQL mode is enabled; otherwise, the column is set to the implicit default value for the column data type and the warning count is incremented. The implicit default value is `0' for numeric types, the empty string (`''') for string types, and the `zero' value for date and time types. See *Note data-type-defaults::. *Note `UPDATE': update. returns the number of rows that were actually changed. The *Note `mysql_info()': mysql-info. C API function returns the number of rows that were matched and updated and the number of warnings that occurred during the *Note `UPDATE': update. You can use `LIMIT ROW_COUNT' to restrict the scope of the *Note `UPDATE': update. A `LIMIT' clause is a rows-matched restriction. The statement stops as soon as it has found ROW_COUNT rows that satisfy the `WHERE' clause, whether or not they actually were changed. If an *Note `UPDATE': update. statement includes an `ORDER BY' clause, the rows are updated in the order specified by the clause. This can be useful in certain situations that might otherwise result in an error. Suppose that a table `t' contains a column `id' that has a unique index. The following statement could fail with a duplicate-key error, depending on the order in which rows are updated: UPDATE t SET id = id + 1; For example, if the table contains 1 and 2 in the `id' column and 1 is updated to 2 before 2 is updated to 3, an error occurs. To avoid this problem, add an `ORDER BY' clause to cause the rows with larger `id' values to be updated before those with smaller values: UPDATE t SET id = id + 1 ORDER BY id DESC; You can also perform *Note `UPDATE': update. operations covering multiple tables. However, you cannot use `ORDER BY' or `LIMIT' with a multiple-table *Note `UPDATE': update. The TABLE_REFERENCES clause lists the tables involved in the join. Its syntax is described in *Note join::. Here is an example: UPDATE items,month SET items.price=month.price WHERE items.id=month.id; The preceding example shows an inner join that uses the comma operator, but multiple-table *Note `UPDATE': update. statements can use any type of join permitted in *Note `SELECT': select. statements, such as `LEFT JOIN'. If you use a multiple-table *Note `UPDATE': update. statement involving `InnoDB' tables for which there are foreign key constraints, the MySQL optimizer might process tables in an order that differs from that of their parent/child relationship. In this case, the statement fails and rolls back. Instead, update a single table and rely on the `ON UPDATE' capabilities that `InnoDB' provides to cause the other tables to be modified accordingly. See *Note innodb-foreign-key-constraints::. Currently, you cannot update a table and select from the same table in a subquery. Index hints (see *Note index-hints::) are accepted but ignored for *Note `UPDATE': update. statements.  File: manual.info, Node: sql-syntax-transactions, Next: sql-syntax-server-administration, Prev: sql-syntax-data-manipulation, Up: sql-syntax 13.3 MySQL Transactional and Locking Statements =============================================== * Menu: * commit:: `START TRANSACTION', `COMMIT', and `ROLLBACK' Syntax * cannot-roll-back:: Statements That Cannot Be Rolled Back * implicit-commit:: Statements That Cause an Implicit Commit * savepoint:: `SAVEPOINT' and `ROLLBACK TO SAVEPOINT' Syntax * lock-tables:: `LOCK TABLES' and `UNLOCK TABLES' Syntax * set-transaction:: `SET TRANSACTION' Syntax * xa:: XA Transactions MySQL supports local transactions (within a given client session) through statements such as *Note `SET autocommit': commit, *Note `START TRANSACTION': commit, *Note `COMMIT': commit, and *Note `ROLLBACK': commit. See *Note commit::. XA transaction support enables MySQL to participate in distributed transactions as well. See *Note xa::.  File: manual.info, Node: commit, Next: cannot-roll-back, Prev: sql-syntax-transactions, Up: sql-syntax-transactions 13.3.1 `START TRANSACTION', `COMMIT', and `ROLLBACK' Syntax ----------------------------------------------------------- START TRANSACTION [WITH CONSISTENT SNAPSHOT] | BEGIN [WORK] COMMIT [WORK] [AND [NO] CHAIN] [[NO] RELEASE] ROLLBACK [WORK] [AND [NO] CHAIN] [[NO] RELEASE] SET autocommit = {0 | 1} The *Note `START TRANSACTION': commit. or *Note `BEGIN': commit. statement begins a new transaction. *Note `COMMIT': commit. commits the current transaction, making its changes permanent. *Note `ROLLBACK': commit. rolls back the current transaction, canceling its changes. The *Note `SET autocommit': commit. statement disables or enables the default autocommit mode for the current session. The optional `WORK' keyword is supported for *Note `COMMIT': commit. and *Note `ROLLBACK': commit, as are the `CHAIN' and `RELEASE' clauses. `CHAIN' and `RELEASE' can be used for additional control over transaction completion. The value of the `completion_type' system variable determines the default completion behavior. See *Note server-system-variables::. *Note*: Within all stored programs (stored procedures and functions, triggers, and events), the parser treats *Note `BEGIN [WORK]': commit. as the beginning of a *Note `BEGIN ... END': begin-end. block. Begin a transaction in this context with *Note `START TRANSACTION': commit. instead. The `AND CHAIN' clause causes a new transaction to begin as soon as the current one ends, and the new transaction has the same isolation level as the just-terminated transaction. The `RELEASE' clause causes the server to disconnect the current client session after terminating the current transaction. Including the `NO' keyword suppresses `CHAIN' or `RELEASE' completion, which can be useful if the `completion_type' system variable is set to cause chaining or release completion by default. By default, MySQL runs with autocommit mode enabled. This means that as soon as you execute a statement that updates (modifies) a table, MySQL stores the update on disk to make it permanent. To disable autocommit mode, use the following statement: SET autocommit=0; After disabling autocommit mode by setting the `autocommit' variable to zero, changes to transaction-safe tables (such as those for `InnoDB' or *Note `NDBCLUSTER': mysql-cluster.) are not made permanent immediately. You must use *Note `COMMIT': commit. to store your changes to disk or *Note `ROLLBACK': commit. to ignore the changes. `autocommit' is a session variable and must be set for each session. If you want to disable autocommit mode for each new connection, see the description of the `autocommit' system variable at *Note server-system-variables::. To disable autocommit mode for a single series of statements, use the *Note `START TRANSACTION': commit. statement: START TRANSACTION; SELECT @A:=SUM(salary) FROM table1 WHERE type=1; UPDATE table2 SET summary=@A WHERE type=1; COMMIT; With *Note `START TRANSACTION': commit, autocommit remains disabled until you end the transaction with *Note `COMMIT': commit. or *Note `ROLLBACK': commit. The autocommit mode then reverts to its previous state. *Note `BEGIN': commit. and *Note `BEGIN WORK': commit. are supported as aliases of *Note `START TRANSACTION': commit. for initiating a transaction. *Note `START TRANSACTION': commit. is standard SQL syntax and is the recommended way to start an ad-hoc transaction. *Important*: Many APIs used for writing MySQL client applications (such as JDBC) provide their own methods for starting transactions that can (and sometimes should) be used instead of sending a *Note `START TRANSACTION': commit. statement from the client. See *Note connectors-apis::, or the documentation for your API, for more information. The *Note `BEGIN': commit. statement differs from the use of the `BEGIN' keyword that starts a *Note `BEGIN ... END': begin-end. compound statement. The latter does not begin a transaction. See *Note begin-end::. You can also begin a transaction like this: START TRANSACTION WITH CONSISTENT SNAPSHOT; The `WITH CONSISTENT SNAPSHOT' clause starts a consistent read for storage engines that are capable of it. This applies only to `InnoDB'. The effect is the same as issuing a *Note `START TRANSACTION': commit. followed by a *Note `SELECT': select. from any `InnoDB' table. See *Note innodb-consistent-read::. The `WITH CONSISTENT SNAPSHOT' clause does not change the current transaction isolation level, so it provides a consistent snapshot only if the current isolation level is one that permits consistent read (`REPEATABLE READ' or `SERIALIZABLE'). Beginning a transaction causes any pending transaction to be committed. See *Note implicit-commit::, for more information. Beginning a transaction also causes table locks acquired with *Note `LOCK TABLES': lock-tables. to be released, as though you had executed *Note `UNLOCK TABLES': lock-tables. Beginning a transaction does not release a global read lock acquired with *Note `FLUSH TABLES WITH READ LOCK': flush. For best results, transactions should be performed using only tables managed by a single transaction-safe storage engine. Otherwise, the following problems can occur: * If you use tables from more than one transaction-safe storage engine (such as `InnoDB' and `Falcon'), and the transaction isolation level is not `SERIALIZABLE', it is possible that when one transaction commits, another ongoing transaction that uses the same tables will see only some of the changes made by the first transaction. That is, the atomicity of transactions is not guaranteed with mixed engines and inconsistencies can result. (If mixed-engine transactions are infrequent, you can use *Note `SET TRANSACTION ISOLATION LEVEL': set-transaction. to set the isolation level to `SERIALIZABLE' on a per-transaction basis as necessary.) * If you use tables that are not transaction-safe within a transaction, changes to those tables are stored at once, regardless of the status of autocommit mode. * If you issue a *Note `ROLLBACK': commit. statement after updating a nontransactional table within a transaction, an `ER_WARNING_NOT_COMPLETE_ROLLBACK' warning occurs. Changes to transaction-safe tables are rolled back, but not changes to nontransaction-safe tables. Each transaction is stored in the binary log in one chunk, upon *Note `COMMIT': commit. Transactions that are rolled back are not logged. (*Exception*: Modifications to nontransactional tables cannot be rolled back. If a transaction that is rolled back includes modifications to nontransactional tables, the entire transaction is logged with a *Note `ROLLBACK': commit. statement at the end to ensure that modifications to the nontransactional tables are replicated.) See *Note binary-log::. You can change the isolation level for transactions with *Note `SET TRANSACTION ISOLATION LEVEL': set-transaction. See *Note set-transaction::. Rolling back can be a slow operation that may occur implicitly without the user having explicitly asked for it (for example, when an error occurs). Because of this, *Note `SHOW PROCESSLIST': show-processlist. displays `Rolling back' in the `State' column for the session, not only for explicit rollbacks performed with the *Note `ROLLBACK': commit. statement but also for implicit rollbacks. *Note*: Beginning with MySQL 5.1.36, `BEGIN', `COMMIT', and `ROLLBACK' are no longer affected by `--replicate-do-db' or `--replicate-ignore-db' rules. (Bug#43263)  File: manual.info, Node: cannot-roll-back, Next: implicit-commit, Prev: commit, Up: sql-syntax-transactions 13.3.2 Statements That Cannot Be Rolled Back -------------------------------------------- Some statements cannot be rolled back. In general, these include data definition language (DDL) statements, such as those that create or drop databases, those that create, drop, or alter tables or stored routines. You should design your transactions not to include such statements. If you issue a statement early in a transaction that cannot be rolled back, and then another statement later fails, the full effect of the transaction cannot be rolled back in such cases by issuing a *Note `ROLLBACK': commit. statement.  File: manual.info, Node: implicit-commit, Next: savepoint, Prev: cannot-roll-back, Up: sql-syntax-transactions 13.3.3 Statements That Cause an Implicit Commit ----------------------------------------------- The statements listed in this section (and any synonyms for them) implicitly end a transaction, as if you had done a *Note `COMMIT': commit. before executing the statement. * *Data definition language (DDL) statements that define or modify database objects.* `ALTER DATABASE ... UPGRADE DATA DIRECTORY NAME', *Note `ALTER EVENT': alter-event, *Note `ALTER PROCEDURE': alter-procedure, *Note `ALTER TABLE': alter-table, *Note `CREATE DATABASE': create-database, *Note `CREATE EVENT': create-event, *Note `CREATE INDEX': create-index, *Note `CREATE PROCEDURE': create-procedure, *Note `CREATE TABLE': create-table, *Note `DROP DATABASE': drop-database, *Note `DROP EVENT': drop-event, *Note `DROP INDEX': drop-index, *Note `DROP PROCEDURE': drop-procedure, *Note `DROP TABLE': drop-table, *Note `RENAME TABLE': rename-table, *Note `TRUNCATE TABLE': truncate-table. *Note `ALTER FUNCTION': alter-function, *Note `CREATE FUNCTION': create-function. and *Note `DROP FUNCTION': drop-function. also cause an implicit commit when used with stored functions, but not with UDFs. (*Note `ALTER FUNCTION': alter-function. can only be used with stored functions.) *Note `ALTER TABLE': alter-table, *Note `CREATE TABLE': create-table, and *Note `DROP TABLE': drop-table. do not commit a transaction if the `TEMPORARY' keyword is used. (This does not apply to other operations on temporary tables such as *Note `CREATE INDEX': create-index, which do cause a commit.) However, although no implicit commit occurs, neither can the statement be rolled back. Therefore, use of such statements will violate transaction atomicity: For example, if you use *Note `CREATE TEMPORARY TABLE': create-table. and then roll back the transaction, the table remains in existence. The *Note `CREATE TABLE': create-table. statement in `InnoDB' is processed as a single transaction. This means that a *Note `ROLLBACK': commit. from the user does not undo *Note `CREATE TABLE': create-table. statements the user made during that transaction. Beginning with MySQL 5.1.3, *Note `ALTER VIEW': alter-view, *Note `CREATE TRIGGER': create-trigger, *Note `CREATE VIEW': create-view, *Note `DROP TRIGGER': drop-trigger, and *Note `DROP VIEW': drop-view. cause an implicit commit. Beginning with MySQL 5.1.15, *Note `CREATE TABLE ... SELECT': create-table. causes an implicit commit before and after the statement is executed when you are creating nontemporary tables. (No commit occurs for `CREATE TEMPORARY TABLE ... SELECT'.) This is to prevent an issue during replication where the table could be created on the master after a rollback, but fail to be recorded in the binary log, and therefore not replicated to the slave. For more information, see Bug#22865. * *Statements that implicitly use or modify tables in the `mysql' database.* Beginning with MySQL 5.1.3, *Note `CREATE USER': create-user, *Note `DROP USER': drop-user, and *Note `RENAME USER': rename-user. cause an implicit commit. Beginning with MySQL 5.1.23, *Note `GRANT': grant, *Note `REVOKE': revoke, and *Note `SET PASSWORD': set-password. statements cause an implicit commit. * *Transaction-control and locking statements.* *Note `BEGIN': commit, *Note `LOCK TABLES': lock-tables, `SET autocommit = 1' (if the value is not already 1), *Note `START TRANSACTION': commit, *Note `UNLOCK TABLES': lock-tables. *Note `UNLOCK TABLES': lock-tables. commits a transaction only if any tables currently have been locked with *Note `LOCK TABLES': lock-tables. This does not occur for *Note `UNLOCK TABLES': lock-tables. following *Note `FLUSH TABLES WITH READ LOCK': flush. because the latter statement does not acquire table-level locks. Transactions cannot be nested. This is a consequence of the implicit commit performed for any current transaction when you issue a *Note `START TRANSACTION': commit. statement or one of its synonyms. Statements that cause an implicit commit cannot be used in an XA transaction while the transaction is in an `ACTIVE' state. The *Note `BEGIN': commit. statement differs from the use of the `BEGIN' keyword that starts a *Note `BEGIN ... END': begin-end. compound statement. The latter does not cause an implicit commit. See *Note begin-end::. * *Data loading statements.* *Note `LOAD DATA INFILE': load-data. Before MySQL 5.1.12, *Note `LOAD DATA INFILE': load-data. caused an implicit commit for all storage engines. As of MySQL 5.1.12, it causes an implicit commit only for tables using the *Note `NDB': mysql-cluster. storage engine. For more information, see Bug#11151. * *Administrative statements.* *Note `CACHE INDEX': cache-index, *Note `LOAD INDEX INTO CACHE': load-index. Beginning with MySQL 5.1.10, *Note `ANALYZE TABLE': analyze-table, *Note `CHECK TABLE': check-table, *Note `OPTIMIZE TABLE': optimize-table, and *Note `REPAIR TABLE': repair-table. cause an implicit commit.  File: manual.info, Node: savepoint, Next: lock-tables, Prev: implicit-commit, Up: sql-syntax-transactions 13.3.4 `SAVEPOINT' and `ROLLBACK TO SAVEPOINT' Syntax ----------------------------------------------------- SAVEPOINT IDENTIFIER ROLLBACK [WORK] TO [SAVEPOINT] IDENTIFIER RELEASE SAVEPOINT IDENTIFIER `InnoDB' supports the SQL statements *Note `SAVEPOINT': savepoint, *Note `ROLLBACK TO SAVEPOINT': commit, *Note `RELEASE SAVEPOINT': commit. and the optional `WORK' keyword for *Note `ROLLBACK': commit. The *Note `SAVEPOINT': savepoint. statement sets a named transaction savepoint with a name of IDENTIFIER. If the current transaction has a savepoint with the same name, the old savepoint is deleted and a new one is set. The *Note `ROLLBACK TO SAVEPOINT': commit. statement rolls back a transaction to the named savepoint without terminating the transaction. Modifications that the current transaction made to rows after the savepoint was set are undone in the rollback, but `InnoDB' does _not_ release the row locks that were stored in memory after the savepoint. (For a new inserted row, the lock information is carried by the transaction ID stored in the row; the lock is not separately stored in memory. In this case, the row lock is released in the undo.) Savepoints that were set at a later time than the named savepoint are deleted. If the *Note `ROLLBACK TO SAVEPOINT': commit. statement returns the following error, it means that no savepoint with the specified name exists: ERROR 1305 (42000): SAVEPOINT IDENTIFIER does not exist The *Note `RELEASE SAVEPOINT': commit. statement removes the named savepoint from the set of savepoints of the current transaction. No commit or rollback occurs. It is an error if the savepoint does not exist. All savepoints of the current transaction are deleted if you execute a *Note `COMMIT': commit, or a *Note `ROLLBACK': commit. that does not name a savepoint. A new savepoint level is created when a stored function is invoked or a trigger is activated. The savepoints on previous levels become unavailable and thus do not conflict with savepoints on the new level. When the function or trigger terminates, any savepoints it created are released and the previous savepoint level is restored.  File: manual.info, Node: lock-tables, Next: set-transaction, Prev: savepoint, Up: sql-syntax-transactions 13.3.5 `LOCK TABLES' and `UNLOCK TABLES' Syntax ----------------------------------------------- * Menu: * lock-tables-and-transactions:: Interaction of Table Locking and Transactions * lock-tables-and-triggers:: `LOCK TABLES' and Triggers * lock-tables-restrictions:: Table-Locking Restrictions and Conditions LOCK TABLES TBL_NAME [[AS] ALIAS] LOCK_TYPE [, TBL_NAME [[AS] ALIAS] LOCK_TYPE] ... LOCK_TYPE: READ [LOCAL] | [LOW_PRIORITY] WRITE UNLOCK TABLES MySQL enables client sessions to acquire table locks explicitly for the purpose of cooperating with other sessions for access to tables, or to prevent other sessions from modifying tables during periods when a session requires exclusive access to them. A session can acquire or release locks only for itself. One session cannot acquire locks for another session or release locks held by another session. Locks may be used to emulate transactions or to get more speed when updating tables. This is explained in more detail later in this section. *Note `LOCK TABLES': lock-tables. explicitly acquires table locks for the current client session. Table locks can be acquired for base tables or views. You must have the `LOCK TABLES' privilege, and the `SELECT' privilege for each object to be locked. For view locking, *Note `LOCK TABLES': lock-tables. adds all base tables used in the view to the set of tables to be locked and locks them automatically. If you lock a table explicitly with *Note `LOCK TABLES': lock-tables, any tables used in triggers are also locked implicitly, as described in *Note lock-tables-and-triggers::. *Note `UNLOCK TABLES': lock-tables. explicitly releases any table locks held by the current session. Another use for *Note `UNLOCK TABLES': lock-tables. is to release the global read lock acquired with the *Note `FLUSH TABLES WITH READ LOCK': flush. statement, which enables you to lock all tables in all databases. See *Note flush::. (This is a very convenient way to get backups if you have a file system such as Veritas that can take snapshots in time.) A table lock protects only against inappropriate reads or writes by other sessions. The session holding the lock, even a read lock, can perform table-level operations such as *Note `DROP TABLE': drop-table. Truncate operations are not transaction-safe, so an error occurs if the session attempts one during an active transaction or while holding a table lock. The following discussion applies only to non-`TEMPORARY' tables. *Note `LOCK TABLES': lock-tables. is permitted (but ignored) for a `TEMPORARY' table. The table can be accessed freely by the session within which it was created, regardless of what other locking may be in effect. No lock is necessary because no other session can see the table. For information about other conditions on the use of *Note `LOCK TABLES': lock-tables. and statements that cannot be used while *Note `LOCK TABLES': lock-tables. is in effect, see *Note lock-tables-restrictions:: *Rules for Lock Acquisition* To acquire table locks within the current session, use the *Note `LOCK TABLES': lock-tables. statement. The following lock types are available: `READ [LOCAL]' lock: * The session that holds the lock can read the table (but not write it). * Multiple sessions can acquire a `READ' lock for the table at the same time. * Other sessions can read the table without explicitly acquiring a `READ' lock. * The `LOCAL' modifier enables nonconflicting *Note `INSERT': insert. statements (concurrent inserts) by other sessions to execute while the lock is held. (See *Note concurrent-inserts::.) However, `READ LOCAL' cannot be used if you are going to manipulate the database using processes external to the server while you hold the lock. For `InnoDB' tables, `READ LOCAL' is the same as `READ'. `[LOW_PRIORITY] WRITE' lock: * The session that holds the lock can read and write the table. * Only the session that holds the lock can access the table. No other session can access it until the lock is released. * Lock requests for the table by other sessions block while the `WRITE' lock is held. * The `LOW_PRIORITY' modifier affects lock scheduling if the `WRITE' lock request must wait, as described later. If the *Note `LOCK TABLES': lock-tables. statement must wait due to locks held by other sessions on any of the tables, it blocks until all locks can be acquired. A session that requires locks must acquire all the locks that it needs in a single *Note `LOCK TABLES': lock-tables. statement. While the locks thus obtained are held, the session can access only the locked tables. For example, in the following sequence of statements, an error occurs for the attempt to access `t2' because it was not locked in the *Note `LOCK TABLES': lock-tables. statement: mysql> LOCK TABLES t1 READ; mysql> SELECT COUNT(*) FROM t1; +----------+ | COUNT(*) | +----------+ | 3 | +----------+ mysql> SELECT COUNT(*) FROM t2; ERROR 1100 (HY000): Table 't2' was not locked with LOCK TABLES Tables in the `INFORMATION_SCHEMA' database are an exception. They can be accessed without being locked explicitly even while a session holds table locks obtained with *Note `LOCK TABLES': lock-tables. You cannot refer to a locked table multiple times in a single query using the same name. Use aliases instead, and obtain a separate lock for the table and each alias: mysql> LOCK TABLE t WRITE, t AS t1 READ; mysql> INSERT INTO t SELECT * FROM t; ERROR 1100: Table 't' was not locked with LOCK TABLES mysql> INSERT INTO t SELECT * FROM t AS t1; The error occurs for the first *Note `INSERT': insert. because there are two references to the same name for a locked table. The second *Note `INSERT': insert. succeeds because the references to the table use different names. If your statements refer to a table by means of an alias, you must lock the table using that same alias. It does not work to lock the table without specifying the alias: mysql> LOCK TABLE t READ; mysql> SELECT * FROM t AS myalias; ERROR 1100: Table 'myalias' was not locked with LOCK TABLES Conversely, if you lock a table using an alias, you must refer to it in your statements using that alias: mysql> LOCK TABLE t AS myalias READ; mysql> SELECT * FROM t; ERROR 1100: Table 't' was not locked with LOCK TABLES mysql> SELECT * FROM t AS myalias; `WRITE' locks normally have higher priority than `READ' locks to ensure that updates are processed as soon as possible. This means that if one session obtains a `READ' lock and then another session requests a `WRITE' lock, subsequent `READ' lock requests wait until the session that requested the `WRITE' lock has obtained the lock and released it. A request for a `LOW_PRIORITY WRITE' lock, by contrast, permits subsequent `READ' lock requests by other sessions to be satisfied first if they occur while the `LOW_PRIORITY WRITE' request is waiting. You should use `LOW_PRIORITY WRITE' locks only if you are sure that eventually there will be a time when no sessions have a `READ' lock. For `InnoDB' tables in transactional mode (autocommit = 0), a waiting `LOW_PRIORITY WRITE' lock acts like a regular `WRITE' lock and causes subsequent `READ' lock requests to wait. *Note `LOCK TABLES': lock-tables. acquires locks as follows: 1. Sort all tables to be locked in an internally defined order. From the user standpoint, this order is undefined. 2. If a table is to be locked with a read and a write lock, put the write lock request before the read lock request. 3. Lock one table at a time until the session gets all locks. This policy ensures that table locking is deadlock free. There are, however, other things you need to be aware of about this policy: If you are using a `LOW_PRIORITY WRITE' lock for a table, it means only that MySQL waits for this particular lock until there are no other sessions that want a `READ' lock. When the session has gotten the `WRITE' lock and is waiting to get the lock for the next table in the lock table list, all other sessions wait for the `WRITE' lock to be released. If this becomes a serious problem with your application, you should consider converting some of your tables to transaction-safe tables. *Rules for Lock Release* When the table locks held by a session are released, they are all released at the same time. A session can release its locks explicitly, or locks may be released implicitly under certain conditions. * A session can release its locks explicitly with *Note `UNLOCK TABLES': lock-tables. * If a session issues a *Note `LOCK TABLES': lock-tables. statement to acquire a lock while already holding locks, its existing locks are released implicitly before the new locks are granted. * If a session begins a transaction (for example, with *Note `START TRANSACTION': commit.), an implicit *Note `UNLOCK TABLES': lock-tables. is performed, which causes existing locks to be released. (For additional information about the interaction between table locking and transactions, see *Note lock-tables-and-transactions::.) If the connection for a client session terminates, whether normally or abnormally, the server implicitly releases all table locks held by the session (transactional and nontransactional). If the client reconnects, the locks will no longer be in effect. In addition, if the client had an active transaction, the server rolls back the transaction upon disconnect, and if reconnect occurs, the new session begins with autocommit enabled. For this reason, clients may wish to disable auto-reconnect. With auto-reconnect in effect, the client is not notified if reconnect occurs but any table locks or current transaction will have been lost. With auto-reconnect disabled, if the connection drops, an error occurs for the next statement issued. The client can detect the error and take appropriate action such as reacquiring the locks or redoing the transaction. See *Note auto-reconnect::. *Note*: If you use *Note `ALTER TABLE': alter-table. on a locked table, it may become unlocked. For example, if you attempt a second *Note `ALTER TABLE': alter-table. operation, the result may be an error `Table 'TBL_NAME' was not locked with LOCK TABLES'. To handle this, lock the table again prior to the second alteration. See also *Note alter-table-problems::.  File: manual.info, Node: lock-tables-and-transactions, Next: lock-tables-and-triggers, Prev: lock-tables, Up: lock-tables 13.3.5.1 Interaction of Table Locking and Transactions ...................................................... *Note `LOCK TABLES': lock-tables. and *Note `UNLOCK TABLES': lock-tables. interact with the use of transactions as follows: * *Note `LOCK TABLES': lock-tables. is not transaction-safe and implicitly commits any active transaction before attempting to lock the tables. * *Note `UNLOCK TABLES': lock-tables. implicitly commits any active transaction, but only if *Note `LOCK TABLES': lock-tables. has been used to acquire table locks. For example, in the following set of statements, *Note `UNLOCK TABLES': lock-tables. releases the global read lock but does not commit the transaction because no table locks are in effect: FLUSH TABLES WITH READ LOCK; START TRANSACTION; SELECT ... ; UNLOCK TABLES; * Beginning a transaction (for example, with *Note `START TRANSACTION': commit.) implicitly commits any current transaction and releases existing locks. * Other statements that implicitly cause transactions to be committed do not release existing locks. For a list of such statements, see *Note implicit-commit::. * The correct way to use *Note `LOCK TABLES': lock-tables. and *Note `UNLOCK TABLES': lock-tables. with transactional tables, such as `InnoDB' tables, is to begin a transaction with `SET autocommit = 0' (not *Note `START TRANSACTION': commit.) followed by *Note `LOCK TABLES': lock-tables, and to not call *Note `UNLOCK TABLES': lock-tables. until you commit the transaction explicitly. For example, if you need to write to table `t1' and read from table `t2', you can do this: SET autocommit=0; LOCK TABLES t1 WRITE, t2 READ, ...; ... DO SOMETHING WITH TABLES T1 AND T2 HERE ... COMMIT; UNLOCK TABLES; When you call *Note `LOCK TABLES': lock-tables, `InnoDB' internally takes its own table lock, and MySQL takes its own table lock. `InnoDB' releases its internal table lock at the next commit, but for MySQL to release its table lock, you have to call *Note `UNLOCK TABLES': lock-tables. You should not have `autocommit = 1', because then `InnoDB' releases its internal table lock immediately after the call of *Note `LOCK TABLES': lock-tables, and deadlocks can very easily happen. `InnoDB' does not acquire the internal table lock at all if `autocommit = 1', to help old applications avoid unnecessary deadlocks. * *Note `ROLLBACK': commit. does not release table locks. * *Note `FLUSH TABLES WITH READ LOCK': flush. acquires a global read lock and not table locks, so it is not subject to the same behavior as *Note `LOCK TABLES': lock-tables. and *Note `UNLOCK TABLES': lock-tables. with respect to table locking and implicit commits. See *Note flush::.  File: manual.info, Node: lock-tables-and-triggers, Next: lock-tables-restrictions, Prev: lock-tables-and-transactions, Up: lock-tables 13.3.5.2 `LOCK TABLES' and Triggers ................................... If you lock a table explicitly with *Note `LOCK TABLES': lock-tables, any tables used in triggers are also locked implicitly: * The locks are taken as the same time as those acquired explicitly with the *Note `LOCK TABLES': lock-tables. statement. * The lock on a table used in a trigger depends on whether the table is used only for reading. If so, a read lock suffices. Otherwise, a write lock is used. * If a table is locked explicitly for reading with *Note `LOCK TABLES': lock-tables, but needs to be locked for writing because it might be modified within a trigger, a write lock is taken rather than a read lock. (That is, an implicit write lock needed due to the table's appearance within a trigger causes an explicit read lock request for the table to be converted to a write lock request.) Suppose that you lock two tables, `t1' and `t2', using this statement: LOCK TABLES t1 WRITE, t2 READ; If `t1' or `t2' have any triggers, tables used within the triggers will also be locked. Suppose that `t1' has a trigger defined like this: CREATE TRIGGER t1_a_ins AFTER INSERT ON t1 FOR EACH ROW BEGIN UPDATE t4 SET count = count+1 WHERE id = NEW.id AND EXISTS (SELECT a FROM t3); INSERT INTO t2 VALUES(1, 2); END; The result of the *Note `LOCK TABLES': lock-tables. statement is that `t1' and `t2' are locked because they appear in the statement, and `t3' and `t4' are locked because they are used within the trigger: * `t1' is locked for writing per the `WRITE' lock request. * `t2' is locked for writing, even though the request is for a `READ' lock. This occurs because `t2' is inserted into within the trigger, so the `READ' request is converted to a `WRITE' request. * `t3' is locked for reading because it is only read from within the trigger. * `t4' is locked for writing because it might be updated within the trigger.  File: manual.info, Node: lock-tables-restrictions, Prev: lock-tables-and-triggers, Up: lock-tables 13.3.5.3 Table-Locking Restrictions and Conditions .................................................. You can safely use *Note `KILL': kill. to terminate a session that is waiting for a table lock. See *Note kill::. You should _not_ lock any tables that you are using with *Note `INSERT DELAYED': insert-delayed. An *Note `INSERT DELAYED': insert-delayed. in this case results in an error because the insert must be handled by a separate thread, not by the session which holds the lock. *Note `LOCK TABLES': lock-tables. and *Note `UNLOCK TABLES': lock-tables. cannot be used within stored programs. For some operations, system tables in the `mysql' database must be accessed. For example, the *Note `HELP': help. statement requires the contents of the server-side help tables, and `CONVERT_TZ()' might need to read the time zone tables. Before MySQL 5.1.17, to perform such operations while a *Note `LOCK TABLES': lock-tables. statement is in effect, you must also lock the requisite system tables explicitly or a lock error occurs. As of 5.1.17, the server implicitly locks the system tables for reading as necessary so that you need not lock them explicitly. These tables are treated as just described: mysql.help_category mysql.help_keyword mysql.help_relation mysql.help_topic mysql.proc mysql.time_zone mysql.time_zone_leap_second mysql.time_zone_name mysql.time_zone_transition mysql.time_zone_transition_type If you want to explicitly place a `WRITE' lock on any of those tables with a *Note `LOCK TABLES': lock-tables. statement, the table must be the only one locked; no other table can be locked with the same statement. Normally, you do not need to lock tables, because all single *Note `UPDATE': update. statements are atomic; no other session can interfere with any other currently executing SQL statement. However, there are a few cases when locking tables may provide an advantage: * If you are going to run many operations on a set of `MyISAM' tables, it is much faster to lock the tables you are going to use. Locking `MyISAM' tables speeds up inserting, updating, or deleting on them because MySQL does not flush the key cache for the locked tables until *Note `UNLOCK TABLES': lock-tables. is called. Normally, the key cache is flushed after each SQL statement. The downside to locking the tables is that no session can update a `READ'-locked table (including the one holding the lock) and no session can access a `WRITE'-locked table other than the one holding the lock. * If you are using tables for a nontransactional storage engine, you must use *Note `LOCK TABLES': lock-tables. if you want to ensure that no other session modifies the tables between a *Note `SELECT': select. and an *Note `UPDATE': update. The example shown here requires *Note `LOCK TABLES': lock-tables. to execute safely: LOCK TABLES trans READ, customer WRITE; SELECT SUM(value) FROM trans WHERE customer_id=SOME_ID; UPDATE customer SET total_value=SUM_FROM_PREVIOUS_STATEMENT WHERE customer_id=SOME_ID; UNLOCK TABLES; Without *Note `LOCK TABLES': lock-tables, it is possible that another session might insert a new row in the `trans' table between execution of the *Note `SELECT': select. and *Note `UPDATE': update. statements. You can avoid using *Note `LOCK TABLES': lock-tables. in many cases by using relative updates (`UPDATE customer SET VALUE=VALUE+NEW_VALUE') or the `LAST_INSERT_ID()' function. See *Note ansi-diff-transactions::. You can also avoid locking tables in some cases by using the user-level advisory lock functions `GET_LOCK()' and `RELEASE_LOCK()'. These locks are saved in a hash table in the server and implemented with `pthread_mutex_lock()' and `pthread_mutex_unlock()' for high speed. See *Note miscellaneous-functions::. See *Note internal-locking::, for more information on locking policy.  File: manual.info, Node: set-transaction, Next: xa, Prev: lock-tables, Up: sql-syntax-transactions 13.3.6 `SET TRANSACTION' Syntax ------------------------------- SET [GLOBAL | SESSION] TRANSACTION ISOLATION LEVEL { READ UNCOMMITTED | READ COMMITTED | REPEATABLE READ | SERIALIZABLE } This statement sets the transaction isolation level globally, for the current session, or for the next transaction: * With the `GLOBAL' keyword, the statement sets the default transaction level globally for all subsequent sessions. Existing sessions are unaffected. * With the `SESSION' keyword, the statement sets the default transaction level for all subsequent transactions performed within the current session. * Without any `SESSION' or `GLOBAL' keyword, the statement sets the isolation level for the next (not started) transaction performed within the current session. A change to the global default isolation level requires the `SUPER' privilege. Any session is free to change its session isolation level (even in the middle of a transaction), or the isolation level for its next transaction. *Note `SET TRANSACTION ISOLATION LEVEL': set-transaction. without `GLOBAL' or `SESSION' is not permitted while there is an active transaction: mysql> START TRANSACTION; Query OK, 0 rows affected (0.02 sec) mysql> SET TRANSACTION ISOLATION LEVEL SERIALIZABLE; ERROR 1568 (25001): Transaction isolation level can't be changed while a transaction is in progress To set the global default isolation level at server startup, use the `--transaction-isolation=LEVEL' option to *Note `mysqld': mysqld. on the command line or in an option file. Values of LEVEL for this option use dashes rather than spaces, so the permissible values are `READ-UNCOMMITTED', `READ-COMMITTED', `REPEATABLE-READ', or `SERIALIZABLE'. For example, to set the default isolation level to `REPEATABLE READ', use these lines in the `[mysqld]' section of an option file: [mysqld] transaction-isolation = REPEATABLE-READ To determine the global and session transaction isolation levels at runtime, check the value of the `tx_isolation' system variable: SELECT @@GLOBAL.tx_isolation, @@tx_isolation; `InnoDB' supports each of the transaction isolation levels described here using different locking strategies. The default level is `REPEATABLE READ'. For additional information about `InnoDB' record-level locks and how it uses them to execute various types of statements, see *Note innodb-record-level-locks::, and *Note innodb-locks-set::. The following list describes how MySQL supports the different transaction levels: * `READ UNCOMMITTED' *Note `SELECT': select. statements are performed in a nonlocking fashion, but a possible earlier version of a row might be used. Thus, using this isolation level, such reads are not consistent. This is also called a `dirty read.' Otherwise, this isolation level works like `READ COMMITTED'. * `READ COMMITTED' A somewhat Oracle-like isolation level with respect to consistent (nonlocking) reads: Each consistent read, even within the same transaction, sets and reads its own fresh snapshot. See *Note innodb-consistent-read::. For locking reads (*Note `SELECT': select. with `FOR UPDATE' or `LOCK IN SHARE MODE'), `InnoDB' locks only index records, not the gaps before them, and thus permits the free insertion of new records next to locked records. For *Note `UPDATE': update. and *Note `DELETE': delete. statements, locking depends on whether the statement uses a unique index with a unique search condition (such as `WHERE id = 100'), or a range-type search condition (such as `WHERE id > 100'). For a unique index with a unique search condition, `InnoDB' locks only the index record found, not the gap before it. For range-type searches, `InnoDB' locks the index range scanned, using gap locks or next-key (gap plus index-record) locks to block insertions by other sessions into the gaps covered by the range. This is necessary because `phantom rows' must be blocked for MySQL replication and recovery to work. *Note*: In MySQL 5.1, if the `READ COMMITTED' isolation level is used or the `innodb_locks_unsafe_for_binlog' system variable is enabled, there is no `InnoDB' gap locking except for foreign-key constraint checking and duplicate-key checking. Also, record locks for nonmatching rows are released after MySQL has evaluated the `WHERE' condition. As of MySQL 5.1, if you use `READ COMMITTED' or enable `innodb_locks_unsafe_for_binlog', you _must_ use row-based binary logging. * `REPEATABLE READ' This is the default isolation level for `InnoDB'. For consistent reads, there is an important difference from the `READ COMMITTED' isolation level: All consistent reads within the same transaction read the snapshot established by the first read. This convention means that if you issue several plain (nonlocking) *Note `SELECT': select. statements within the same transaction, these *Note `SELECT': select. statements are consistent also with respect to each other. See *Note innodb-consistent-read::. For locking reads (*Note `SELECT': select. with `FOR UPDATE' or `LOCK IN SHARE MODE'), *Note `UPDATE': update, and *Note `DELETE': delete. statements, locking depends on whether the statement uses a unique index with a unique search condition, or a range-type search condition. For a unique index with a unique search condition, `InnoDB' locks only the index record found, not the gap before it. For other search conditions, `InnoDB' locks the index range scanned, using gap locks or next-key (gap plus index-record) locks to block insertions by other sessions into the gaps covered by the range. * `SERIALIZABLE' This level is like `REPEATABLE READ', but `InnoDB' implicitly converts all plain *Note `SELECT': select. statements to *Note `SELECT ... LOCK IN SHARE MODE': select. if autocommit is disabled. If autocommit is enabled, the *Note `SELECT': select. is its own transaction. It therefore is known to be read only and can be serialized if performed as a consistent (nonlocking) read and need not block for other transactions. (This means that to force a plain *Note `SELECT': select. to block if other transactions have modified the selected rows, you should disable autocommit.)  File: manual.info, Node: xa, Prev: set-transaction, Up: sql-syntax-transactions 13.3.7 XA Transactions ---------------------- * Menu: * xa-statements:: XA Transaction SQL Syntax * xa-states:: XA Transaction States Support for XA transactions is available for the `InnoDB' storage engine. The MySQL XA implementation is based on the X/Open CAE document `Distributed Transaction Processing: The XA Specification'. This document is published by The Open Group and available at `http://www.opengroup.org/public/pubs/catalog/c193.htm'. Limitations of the current XA implementation are described in *Note xa-restrictions::. On the client side, there are no special requirements. The XA interface to a MySQL server consists of SQL statements that begin with the `XA' keyword. MySQL client programs must be able to send SQL statements and to understand the semantics of the XA statement interface. They do not need be linked against a recent client library. Older client libraries also will work. Currently, among the MySQL Connectors, MySQL Connector/J 5.0.0 supports XA directly (by means of a class interface that handles the Xan SQL statement interface for you). XA supports distributed transactions; that is, the ability to permit multiple separate transactional resources to participate in a global transaction. Transactional resources often are RDBMSs but may be other kinds of resources. A global transaction involves several actions that are transactional in themselves, but that all must either complete successfully as a group, or all be rolled back as a group. In essence, this extends ACID properties `up a level' so that multiple ACID transactions can be executed in concert as components of a global operation that also has ACID properties. (However, for a distributed transaction, you must use the `SERIALIZABLE' isolation level to achieve ACID properties. It is enough to use `REPEATABLE READ' for a nondistributed transaction, but not for a distributed transaction.) Some examples of distributed transactions: * An application may act as an integration tool that combines a messaging service with an RDBMS. The application makes sure that transactions dealing with message sending, retrieval, and processing that also involve a transactional database all happen in a global transaction. You can think of this as `transactional email.' * An application performs actions that involve different database servers, such as a MySQL server and an Oracle server (or multiple MySQL servers), where actions that involve multiple servers must happen as part of a global transaction, rather than as separate transactions local to each server. * A bank keeps account information in an RDBMS and distributes and receives money through automated teller machines (ATMs). It is necessary to ensure that ATM actions are correctly reflected in the accounts, but this cannot be done with the RDBMS alone. A global transaction manager integrates the ATM and database resources to ensure overall consistency of financial transactions. Applications that use global transactions involve one or more Resource Managers and a Transaction Manager: * A Resource Manager (RM) provides access to transactional resources. A database server is one kind of resource manager. It must be possible to either commit or roll back transactions managed by the RM. * A Transaction Manager (TM) coordinates the transactions that are part of a global transaction. It communicates with the RMs that handle each of these transactions. The individual transactions within a global transaction are `branches' of the global transaction. Global transactions and their branches are identified by a naming scheme described later. The MySQL implementation of XA MySQL enables a MySQL server to act as a Resource Manager that handles XA transactions within a global transaction. A client program that connects to the MySQL server acts as the Transaction Manager. To carry out a global transaction, it is necessary to know which components are involved, and bring each component to a point when it can be committed or rolled back. Depending on what each component reports about its ability to succeed, they must all commit or roll back as an atomic group. That is, either all components must commit, or all components musts roll back. To manage a global transaction, it is necessary to take into account that any component or the connecting network might fail. The process for executing a global transaction uses two-phase commit (2PC). This takes place after the actions performed by the branches of the global transaction have been executed. 1. In the first phase, all branches are prepared. That is, they are told by the TM to get ready to commit. Typically, this means each RM that manages a branch records the actions for the branch in stable storage. The branches indicate whether they are able to do this, and these results are used for the second phase. 2. In the second phase, the TM tells the RMs whether to commit or roll back. If all branches indicated when they were prepared that they will be able to commit, all branches are told to commit. If any branch indicated when it was prepared that it will not be able to commit, all branches are told to roll back. In some cases, a global transaction might use one-phase commit (1PC). For example, when a Transaction Manager finds that a global transaction consists of only one transactional resource (that is, a single branch), that resource can be told to prepare and commit at the same time.  File: manual.info, Node: xa-statements, Next: xa-states, Prev: xa, Up: xa 13.3.7.1 XA Transaction SQL Syntax .................................. To perform XA transactions in MySQL, use the following statements: XA {START|BEGIN} XID [JOIN|RESUME] XA END XID [SUSPEND [FOR MIGRATE]] XA PREPARE XID XA COMMIT XID [ONE PHASE] XA ROLLBACK XID XA RECOVER For *Note `XA START': xa-statements, the `JOIN' and `RESUME' clauses are not supported. For *Note `XA END': xa-statements. the `SUSPEND [FOR MIGRATE]' clause is not supported. Each XA statement begins with the `XA' keyword, and most of them require an XID value. An XID is an XA transaction identifier. It indicates which transaction the statement applies to. XID values are supplied by the client, or generated by the MySQL server. An XID value has from one to three parts: XID: GTRID [, BQUAL [, FORMATID ]] GTRID is a global transaction identifier, BQUAL is a branch qualifier, and FORMATID is a number that identifies the format used by the GTRID and BQUAL values. As indicated by the syntax, BQUAL and FORMATID are optional. The default BQUAL value is `''' if not given. The default FORMATID value is 1 if not given. GTRID and BQUAL must be string literals, each up to 64 bytes (not characters) long. GTRID and BQUAL can be specified in several ways. You can use a quoted string (`'ab''), hex string (`0x6162', `X'ab''), or bit value (`b'NNNN''). FORMATID is an unsigned integer. The GTRID and BQUAL values are interpreted in bytes by the MySQL server's underlying XA support routines. However, while an SQL statement containing an XA statement is being parsed, the server works with some specific character set. To be safe, write GTRID and BQUAL as hex strings. XID values typically are generated by the Transaction Manager. Values generated by one TM must be different from values generated by other TMs. A given TM must be able to recognize its own XID values in a list of values returned by the *Note `XA RECOVER': xa-statements. statement. `XA START XID' starts an XA transaction with the given XID value. Each XA transaction must have a unique XID value, so the value must not currently be used by another XA transaction. Uniqueness is assessed using the GTRID and BQUAL values. All following XA statements for the XA transaction must be specified using the same XID value as that given in the *Note `XA START': xa-statements. statement. If you use any of those statements but specify an XID value that does not correspond to some existing XA transaction, an error occurs. One or more XA transactions can be part of the same global transaction. All XA transactions within a given global transaction must use the same GTRID value in the XID value. For this reason, GTRID values must be globally unique so that there is no ambiguity about which global transaction a given XA transaction is part of. The BQUAL part of the XID value must be different for each XA transaction within a global transaction. (The requirement that BQUAL values be different is a limitation of the current MySQL XA implementation. It is not part of the XA specification.) The *Note `XA RECOVER': xa-statements. statement returns information for those XA transactions on the MySQL server that are in the `PREPARED' state. (See *Note xa-states::.) The output includes a row for each such XA transaction on the server, regardless of which client started it. *Note `XA RECOVER': xa-statements. output rows look like this (for an example XID value consisting of the parts `'abc'', `'def'', and `7'): mysql> XA RECOVER; +----------+--------------+--------------+--------+ | formatID | gtrid_length | bqual_length | data | +----------+--------------+--------------+--------+ | 7 | 3 | 3 | abcdef | +----------+--------------+--------------+--------+ The output columns have the following meanings: * `formatID' is the FORMATID part of the transaction XID * `gtrid_length' is the length in bytes of the GTRID part of the XID * `bqual_length' is the length in bytes of the BQUAL part of the XID * `data' is the concatenation of the GTRID and BQUAL parts of the XID  File: manual.info, Node: xa-states, Prev: xa-statements, Up: xa 13.3.7.2 XA Transaction States .............................. An XA transaction progresses through the following states: 1. Use *Note `XA START': xa-statements. to start an XA transaction and put it in the `ACTIVE' state. 2. For an `ACTIVE' XA transaction, issue the SQL statements that make up the transaction, and then issue an *Note `XA END': xa-statements. statement. *Note `XA END': xa-statements. puts the transaction in the `IDLE' state. 3. For an `IDLE' XA transaction, you can issue either an *Note `XA PREPARE': xa-statements. statement or an `XA COMMIT ... ONE PHASE' statement: * *Note `XA PREPARE': xa-statements. puts the transaction in the `PREPARED' state. An *Note `XA RECOVER': xa-statements. statement at this point will include the transaction's XID value in its output, because *Note `XA RECOVER': xa-statements. lists all XA transactions that are in the `PREPARED' state. * `XA COMMIT ... ONE PHASE' prepares and commits the transaction. The XID value will not be listed by *Note `XA RECOVER': xa-statements. because the transaction terminates. 4. For a `PREPARED' XA transaction, you can issue an *Note `XA COMMIT': xa-statements. statement to commit and terminate the transaction, or *Note `XA ROLLBACK': xa-statements. to roll back and terminate the transaction. Here is a simple XA transaction that inserts a row into a table as part of a global transaction: mysql> XA START 'xatest'; Query OK, 0 rows affected (0.00 sec) mysql> INSERT INTO mytable (i) VALUES(10); Query OK, 1 row affected (0.04 sec) mysql> XA END 'xatest'; Query OK, 0 rows affected (0.00 sec) mysql> XA PREPARE 'xatest'; Query OK, 0 rows affected (0.00 sec) mysql> XA COMMIT 'xatest'; Query OK, 0 rows affected (0.00 sec) Within the context of a given client connection, XA transactions and local (non-XA) transactions are mutually exclusive. For example, if *Note `XA START': xa-statements. has been issued to begin an XA transaction, a local transaction cannot be started until the XA transaction has been committed or rolled back. Conversely, if a local transaction has been started with *Note `START TRANSACTION': commit, no XA statements can be used until the transaction has been committed or rolled back. Note that if an XA transaction is in the `ACTIVE' state, you cannot issue any statements that cause an implicit commit. That would violate the XA contract because you could not roll back the XA transaction. You will receive the following error if you try to execute such a statement: ERROR 1399 (XAE07): XAER_RMFAIL: The command cannot be executed when global transaction is in the ACTIVE state Statements to which the preceding remark applies are listed at *Note implicit-commit::.  File: manual.info, Node: sql-syntax-server-administration, Next: sql-syntax-replication, Prev: sql-syntax-transactions, Up: sql-syntax 13.4 Database Administration Statements ======================================= * Menu: * account-management-sql:: Account Management Statements * table-maintenance-sql:: Table Maintenance Statements * plugin-sql:: Plugin and User-Defined Function Statements * set-option:: `SET' Syntax * show:: `SHOW' Syntax * other-administrative-sql:: Other Administrative Statements  File: manual.info, Node: account-management-sql, Next: table-maintenance-sql, Prev: sql-syntax-server-administration, Up: sql-syntax-server-administration 13.4.1 Account Management Statements ------------------------------------ * Menu: * create-user:: `CREATE USER' Syntax * drop-user:: `DROP USER' Syntax * grant:: `GRANT' Syntax * rename-user:: `RENAME USER' Syntax * revoke:: `REVOKE' Syntax * set-password:: `SET PASSWORD' Syntax MySQL account information is stored in the tables of the `mysql' database. This database and the access control system are discussed extensively in *Note server-administration::, which you should consult for additional details. *Important*: Some releases of MySQL introduce changes to the structure of the grant tables to add new privileges or features. Whenever you update to a new version of MySQL, you should update your grant tables to make sure that they have the current structure so that you can take advantage of any new capabilities. See *Note mysql-upgrade::.  File: manual.info, Node: create-user, Next: drop-user, Prev: account-management-sql, Up: account-management-sql 13.4.1.1 `CREATE USER' Syntax ............................. CREATE USER USER_SPECIFICATION [, USER_SPECIFICATION] ... USER_SPECIFICATION: USER [IDENTIFIED BY [PASSWORD] 'PASSWORD'] The *Note `CREATE USER': create-user. statement creates new MySQL accounts. To use it, you must have the global `CREATE USER' privilege or the `INSERT' privilege for the `mysql' database. For each account, *Note `CREATE USER': create-user. creates a new row in the `mysql.user' table and assigns the account no privileges. An error occurs if the account already exists. Each account name uses the format described in *Note account-names::. For example: CREATE USER 'jeffrey'@'localhost' IDENTIFIED BY 'mypass'; If you specify only the user name part of the account name, a host name part of `'%'' is used. The user specification may indicate how the user should authenticate when connecting to the server: * To enable the user to connect with no password (which is _insecure_), include no `IDENTIFIED BY' clause: CREATE USER 'jeffrey'@'localhost'; * To assign a password, use `IDENTIFIED BY' with the literal plaintext password value: CREATE USER 'jeffrey'@'localhost' IDENTIFIED BY 'mypass'; * To avoid specifying the plaintext password if you know its hash value (the value that `PASSWORD()' would return for the password), specify the hash value preceded by the keyword `PASSWORD': CREATE USER 'jeffrey'@'localhost' IDENTIFIED BY PASSWORD '*90E462C37378CED12064BB3388827D2BA3A9B689'; For additional information about setting passwords, see *Note assigning-passwords::. *Important*: *Note `CREATE USER': create-user. may be recorded in server logs or in a history file such as `~/.mysql_history', which means that plaintext passwords may be read by anyone having read access to that information. See *Note password-security::. *Important*: Some releases of MySQL introduce changes to the structure of the grant tables to add new privileges or features. Whenever you update to a new version of MySQL, you should update your grant tables to make sure that they have the current structure so that you can take advantage of any new capabilities. See *Note mysql-upgrade::.  File: manual.info, Node: drop-user, Next: grant, Prev: create-user, Up: account-management-sql 13.4.1.2 `DROP USER' Syntax ........................... DROP USER USER [, USER] ... The *Note `DROP USER': drop-user. statement removes one or more MySQL accounts and their privileges. It removes privilege rows for the account from all grant tables. To use this statement, you must have the global `CREATE USER' privilege or the `DELETE' privilege for the `mysql' database. Each account name uses the format described in *Note account-names::. For example: DROP USER 'jeffrey'@'localhost'; If you specify only the user name part of the account name, a host name part of `'%'' is used. *Important*: *Note `DROP USER': drop-user. does not automatically close any open user sessions. Rather, in the event that a user with an open session is dropped, the statement does not take effect until that user's session is closed. Once the session is closed, the user is dropped, and that user's next attempt to log in will fail. _This is by design_. *Note `DROP USER': drop-user. does not automatically drop or invalidate databases or objects within them that the old user created. This includes stored programs or views for which the `DEFINER' attribute names the dropped user. Attempts to access such objects may produce an error if they execute in definer security context. (For information about security context, see *Note stored-programs-security::.)  File: manual.info, Node: grant, Next: rename-user, Prev: drop-user, Up: account-management-sql 13.4.1.3 `GRANT' Syntax ....................... GRANT PRIV_TYPE [(COLUMN_LIST)] [, PRIV_TYPE [(COLUMN_LIST)]] ... ON [OBJECT_TYPE] PRIV_LEVEL TO USER_SPECIFICATION [, USER_SPECIFICATION] ... [REQUIRE {NONE | SSL_OPTION [[AND] SSL_OPTION] ...}] [WITH WITH_OPTION ...] OBJECT_TYPE: TABLE | FUNCTION | PROCEDURE PRIV_LEVEL: * | *.* | DB_NAME.* | DB_NAME.TBL_NAME | TBL_NAME | DB_NAME.ROUTINE_NAME USER_SPECIFICATION: USER [IDENTIFIED BY [PASSWORD] 'PASSWORD'] SSL_OPTION: SSL | X509 | CIPHER 'CIPHER' | ISSUER 'ISSUER' | SUBJECT 'SUBJECT' WITH_OPTION: GRANT OPTION | MAX_QUERIES_PER_HOUR COUNT | MAX_UPDATES_PER_HOUR COUNT | MAX_CONNECTIONS_PER_HOUR COUNT | MAX_USER_CONNECTIONS COUNT The *Note `GRANT': grant. statement grants privileges to MySQL user accounts. *Note `GRANT': grant. also serves to specify other account characteristics such as use of secure connections and limits on access to server resources. To use *Note `GRANT': grant, you must have the `GRANT OPTION' privilege, and you must have the privileges that you are granting. Normally, a database administrator first uses *Note `CREATE USER': create-user. to create an account, then *Note `GRANT': grant. to define its privileges and characteristics. For example: CREATE USER 'jeffrey'@'localhost' IDENTIFIED BY 'mypass'; GRANT ALL ON db1.* TO 'jeffrey'@'localhost'; GRANT SELECT ON db2.invoice TO 'jeffrey'@'localhost'; GRANT USAGE ON *.* TO 'jeffrey'@'localhost' WITH MAX_QUERIES_PER_HOUR 90; However, if an account named in a *Note `GRANT': grant. statement does not already exist, *Note `GRANT': grant. may create it under the conditions described later in the discussion of the `NO_AUTO_CREATE_USER' SQL mode. The *Note `REVOKE': revoke. statement is related to *Note `GRANT': grant. and enables administrators to remove account privileges. See *Note revoke::. To determine what privileges an account has, use *Note `SHOW GRANTS': show-grants. See *Note show-grants::. There are several aspects to the `GRANT' statement, described under the following topics in this section: * Privileges Supported by MySQL * Global Privileges * Database Privileges * Table Privileges * Column Privileges * Stored Routine Privileges * Account Names and Passwords * Other Account Characteristics * MySQL and Standard SQL Versions of *Note `GRANT': grant. *Important*: Some releases of MySQL introduce changes to the structure of the grant tables to add new privileges or features. Whenever you update to a new version of MySQL, you should update your grant tables to make sure that they have the current structure so that you can take advantage of any new capabilities. See *Note mysql-upgrade::. * Privileges Supported by MySQL * The following table summarizes the permissible PRIV_TYPE privilege types that can be specified for the *Note `GRANT': grant. and *Note `REVOKE': revoke. statements. For additional information about these privileges, see *Note privileges-provided::. *Permissible Privileges for `GRANT' and `REVOKE'* Privilege Meaning `ALL [PRIVILEGES]' Grant all privileges at specified access level except `GRANT OPTION' `ALTER' Enable use of *Note `ALTER TABLE': alter-table. `ALTER ROUTINE' Enable stored routines to be altered or dropped `CREATE' Enable database and table creation `CREATE ROUTINE' Enable stored routine creation `CREATE TEMPORARY Enable use of *Note `CREATE TEMPORARY TABLE': TABLES' create-table. `CREATE USER' Enable use of *Note `CREATE USER': create-user, *Note `DROP USER': drop-user, *Note `RENAME USER': rename-user, and *Note `REVOKE ALL PRIVILEGES': revoke. `CREATE VIEW' Enable views to be created or altered `DELETE' Enable use of *Note `DELETE': delete. `DROP' Enable databases, tables, and views to be dropped `EVENT' Enable use of events for the Event Scheduler `EXECUTE' Enable the user to execute stored routines `FILE' Enable the user to cause the server to read or write files `GRANT OPTION' Enable privileges to be granted to or removed from other accounts `INDEX' Enable indexes to be created or dropped `INSERT' Enable use of *Note `INSERT': insert. `LOCK TABLES' Enable use of *Note `LOCK TABLES': lock-tables. on tables for which you have the *Note `SELECT': select. privilege `PROCESS' Enable the user to see all processes with *Note `SHOW PROCESSLIST': show-processlist. `REFERENCES' Not implemented `RELOAD' Enable use of *Note `FLUSH': flush. operations `REPLICATION CLIENT' Enable the user to ask where master or slave servers are `REPLICATION SLAVE' Enable replication slaves to read binary log events from the master `SELECT' Enable use of *Note `SELECT': select. `SHOW DATABASES' Enable *Note `SHOW DATABASES': show-databases. to show all databases `SHOW VIEW' Enable use of *Note `SHOW CREATE VIEW': show-create-view. `SHUTDOWN' Enable use of *Note `mysqladmin shutdown': mysqladmin. `SUPER' Enable use of other administrative operations such as *Note `CHANGE MASTER TO': change-master-to, *Note `KILL': kill, *Note `PURGE BINARY LOGS': purge-binary-logs, *Note `SET GLOBAL': set-option, and *Note `mysqladmin debug': mysqladmin. command `TRIGGER' Enable trigger operations `UPDATE' Enable use of *Note `UPDATE': update. `USAGE' Synonym for `no privileges' The `EVENT' and `TRIGGER' privileges were added in MySQL 5.1.6. A trigger is associated with a table, so to create or drop a trigger, you must have the `TRIGGER' privilege for the table, not the trigger. (Before MySQL 5.1.6, the `SUPER' privilege was required to create or drop triggers.) In *Note `GRANT': grant. statements, the `ALL [PRIVILEGES]' privilege is named by itself and cannot be specified along with other privileges. It stands for all privileges available for the level at which privileges are to be granted except for the `GRANT OPTION' privilege. `USAGE' can be specified to create a user that has no privileges, or to specify the `REQUIRE' or `WITH' clauses for an account without changing its existing privileges. MySQL account information is stored in the tables of the `mysql' database. This database and the access control system are discussed extensively in *Note privilege-system::, which you should consult for additional details. If the grant tables hold privilege rows that contain mixed-case database or table names and the `lower_case_table_names' system variable is set to a nonzero value, *Note `REVOKE': revoke. cannot be used to revoke these privileges. It will be necessary to manipulate the grant tables directly. (*Note `GRANT': grant. will not create such rows when `lower_case_table_names' is set, but such rows might have been created prior to setting that variable.) Privileges can be granted at several levels, depending on the syntax used for the `ON' clause. For *Note `REVOKE': revoke, the same `ON' syntax specifies which privileges to take away. The examples shown here include no `IDENTIFIED BY 'PASSWORD'' clause for brevity, but you should include one if the account does not already exist, to avoid creating an insecure account that has no password. * Global Privileges * Global privileges are administrative or apply to all databases on a given server. To assign global privileges, use `ON *.*' syntax: GRANT ALL ON *.* TO 'someuser'@'somehost'; GRANT SELECT, INSERT ON *.* TO 'someuser'@'somehost'; Before MySQL 5.1.12, privileges also are assigned at the global level if you use `ON *' syntax and you have _not_ selected a default database. As of 5.1.12, `ON *' requires a default database and produces an error is there is none. The `CREATE USER', `FILE', `PROCESS', `RELOAD', `REPLICATION CLIENT', `REPLICATION SLAVE', `SHOW DATABASES', `SHUTDOWN', and `SUPER' privileges are administrative and can only be granted globally. Other privileges can be granted globally or at more specific levels. MySQL stores global privileges in the `mysql.user' table. * Database Privileges * Database privileges apply to all objects in a given database. To assign database-level privileges, use `ON DB_NAME.*' syntax: GRANT ALL ON mydb.* TO 'someuser'@'somehost'; GRANT SELECT, INSERT ON mydb.* TO 'someuser'@'somehost'; If you use `ON *' syntax (rather than `ON *.*' and you have selected a default database, privileges are assigned at the database level for the default database. An error occurs if there is no default database. The `CREATE', `DROP', `EVENT', and `GRANT OPTION' privileges can be specified at the database level. Table or routine privileges also can be specified at the database level, in which case they apply to all tables or routines in the database. MySQL stores database privileges in the `mysql.db' table. * Table Privileges * Table privileges apply to all columns in a given table. To assign table-level privileges, use `ON DB_NAME.TBL_NAME' syntax: GRANT ALL ON mydb.mytbl TO 'someuser'@'somehost'; GRANT SELECT, INSERT ON mydb.mytbl TO 'someuser'@'somehost'; If you specify TBL_NAME rather than DB_NAME.TBL_NAME, the statement applies to TBL_NAME in the default database. An error occurs if there is no default database. The permissible column-level PRIV_TYPE values are `ALTER', `CREATE VIEW', `CREATE', `DELETE', `DROP', `GRANT OPTION', `INDEX', `INSERT', `SELECT', `SHOW VIEW', `TRIGGER', and `UPDATE'. MySQL stores table privileges in the `mysql.tables_priv' table. * Column Privileges * Column privileges apply to single columns in a given table. Each privilege to be granted at the column level must be followed by the column or columns, enclosed within parentheses. GRANT SELECT (col1), INSERT (col1,col2) ON mydb.mytbl TO 'someuser'@'somehost'; The permissible PRIV_TYPE values for a column (that is, when you use a COLUMN_LIST clause) are `INSERT', `SELECT', and `UPDATE'. MySQL stores column privileges in the `mysql.columns_priv' table. * Stored Routine Privileges * The `ALTER ROUTINE', `CREATE ROUTINE', `EXECUTE', and `GRANT OPTION' privileges apply to stored routines (procedures and functions). They can be granted at the global and database levels. Except for `CREATE ROUTINE', these privileges can be granted at the routine level for individual routines. GRANT CREATE ROUTINE ON mydb.* TO 'someuser'@'somehost'; GRANT EXECUTE ON PROCEDURE mydb.myproc TO 'someuser'@'somehost'; The permissible PRIV_TYPE values at the routine level are `ALTER ROUTINE', `EXECUTE', and `GRANT OPTION'. `CREATE ROUTINE' is not a routine-level privilege because you must have this privilege to create a routine in the first place. MySQL stores routine-level privileges in the `mysql.procs_priv' table. For the global, database, table, and routine levels, *Note `GRANT ALL': grant. assigns only the privileges that exist at the level you are granting. For example, `GRANT ALL ON DB_NAME.*' is a database-level statement, so it does not grant any global-only privileges such as `FILE'. The OBJECT_TYPE clause, if present, should be specified as `TABLE', `FUNCTION', or `PROCEDURE' when the following object is a table, a stored function, or a stored procedure. The privileges for a database, table, column, or routine are formed additively as the logical `OR' of the privileges at each of the privilege levels. For example, if a user has a global `SELECT' privilege, the privilege cannot be denied by an absence of the privilege at the database, table, or column level. Details of the privilege-checking procedure are presented in *Note request-access::. MySQL enables you to grant privileges on databases or tables that do not exist. For tables, the privileges to be granted must include the `CREATE' privilege. _This behavior is by design_, and is intended to enable the database administrator to prepare user accounts and privileges for databases or tables that are to be created at a later time. *Important*: _MySQL does not automatically revoke any privileges when you drop a database or table_. However, if you drop a routine, any routine-level privileges granted for that routine are revoked. * Account Names and Passwords * The USER value indicates the MySQL account to which the *Note `GRANT': grant. statement applies. To accommodate granting rights to users from arbitrary hosts, MySQL supports specifying the USER value in the form `USER_NAME@HOST_NAME'. If a USER_NAME or HOST_NAME value is legal as an unquoted identifier, you need not quote it. However, quotation marks are necessary to specify a USER_NAME string containing special characters (such as ``-''), or a HOST_NAME string containing special characters or wildcard characters (such as ``%''); for example, `'test-user'@'%.com''. Quote the user name and host name separately. You can specify wildcards in the host name. For example, `USER_NAME@'%.example.com'' applies to USER_NAME for any host in the `example.com' domain, and `USER_NAME@'192.168.1.%'' applies to USER_NAME for any host in the `192.168.1' class C subnet. The simple form USER_NAME is a synonym for `USER_NAME@'%''. _MySQL does not support wildcards in user names_. To refer to an anonymous user, specify an account with an empty user name with the *Note `GRANT': grant. statement: GRANT ALL ON test.* TO ''@'localhost' ... In this case, any user who connects from the local host with the correct password for the anonymous user will be permitted access, with the privileges associated with the anonymous-user account. For additional information about user name and host name values in account names, see *Note account-names::. To specify quoted values, quote database, table, column, and routine names as identifiers. Quote user names and host names as identifiers or as strings. Quote passwords as strings. For string-quoting and identifier-quoting guidelines, see *Note string-syntax::, and *Note identifiers::. The ``_'' and ``%'' wildcards are permitted when specifying database names in *Note `GRANT': grant. statements that grant privileges at the global or database levels. This means, for example, that if you want to use a ``_'' character as part of a database name, you should specify it as ``\_'' in the *Note `GRANT': grant. statement, to prevent the user from being able to access additional databases matching the wildcard pattern; for example, `GRANT ... ON `foo\_bar`.* TO ...'. *Warning*: If you permit anonymous users to connect to the MySQL server, you should also grant privileges to all local users as `USER_NAME@localhost'. Otherwise, the anonymous user account for `localhost' in the `mysql.user' table (created during MySQL installation) is used when named users try to log in to the MySQL server from the local machine. For details, see *Note connection-access::. To determine whether the preceding warning applies to you, execute the following query, which lists any anonymous users: SELECT Host, User FROM mysql.user WHERE User=''; To avoid the problem just described, delete the local anonymous user account using this statement: DROP USER ''@'localhost'; *Note `GRANT': grant. supports host names up to 60 characters long. Database, table, column, and routine names can be up to 64 characters. User names can be up to 16 characters. *Warning*: _The permissible length for user names cannot be changed by altering the `mysql.user' table. Attempting to do so results in unpredictable behavior which may even make it impossible for users to log in to the MySQL server_. You should never alter any of the tables in the `mysql' database in any manner whatsoever except by means of the procedure described in *Note mysql-upgrade::. The user specification may indicate how the user should authenticate when connecting to the server, through inclusion of an `IDENTIFIED BY' clause. The syntax is the same as for the *Note `CREATE USER': create-user. statement. See *Note create-user::. When the `IDENTIFIED BY' clause is present and you have global grant privileges, the password becomes the new password for the account, even if the account exists and already has a password. With no `IDENTIFIED BY' clause, the account password remains unchanged. If the `NO_AUTO_CREATE_USER' SQL mode is not enabled and the account named in a *Note `GRANT': grant. statement does not exist in the `mysql.user' table, *Note `GRANT': grant. creates it. If you specify no `IDENTIFIED BY' clause or provide an empty password, the user has no password. _This is very insecure._ If `NO_AUTO_CREATE_USER' is enabled and the account does not exist, *Note `GRANT': grant. fails and does not create the account unless the `IDENTIFIED BY' clause is given to provide a nonempty password. *Important*: *Note `GRANT': grant. may be recorded in server logs or in a history file such as `~/.mysql_history', which means that plaintext passwords may be read by anyone having read access to that information. See *Note password-security::. * Other Account Characteristics * The `WITH' clause is used for several purposes: * To enable a user to grant privileges to other users * To specify resource limits for a user * To specify whether and how a user must use secure connections to the server The `WITH GRANT OPTION' clause gives the user the ability to give to other users any privileges the user has at the specified privilege level. You should be careful to whom you give the `GRANT OPTION' privilege because two users with different privileges may be able to combine privileges! You cannot grant another user a privilege which you yourself do not have; the `GRANT OPTION' privilege enables you to assign only those privileges which you yourself possess. Be aware that when you grant a user the `GRANT OPTION' privilege at a particular privilege level, any privileges the user possesses (or may be given in the future) at that level can also be granted by that user to other users. Suppose that you grant a user the `INSERT' privilege on a database. If you then grant the `SELECT' privilege on the database and specify `WITH GRANT OPTION', that user can give to other users not only the `SELECT' privilege, but also `INSERT'. If you then grant the `UPDATE' privilege to the user on the database, the user can grant `INSERT', `SELECT', and `UPDATE'. For a nonadministrative user, you should not grant the `ALTER' privilege globally or for the `mysql' database. If you do that, the user can try to subvert the privilege system by renaming tables! For additional information about security risks associated with particular privileges, see *Note privileges-provided::. Several `WITH' clause options specify limits on use of server resources by an account: * The `MAX_QUERIES_PER_HOUR COUNT', `MAX_UPDATES_PER_HOUR COUNT', and `MAX_CONNECTIONS_PER_HOUR COUNT' limits restrict the number of queries, updates, and connections to the server permitted to this account during any given one-hour period. (Queries for which results are served from the query cache do not count against the `MAX_QUERIES_PER_HOUR' limit.) If COUNT is `0' (the default), this means that there is no limitation for the account. * The `MAX_USER_CONNECTIONS COUNT' limit restricts the maximum number of simultaneous connections to the server by the account. A nonzero COUNT specifies the limit for the account explicitly. If COUNT is `0' (the default), the server determines the number of simultaneous connections for the account from the global value of the `max_user_connections' system variable. If `max_user_connections' is also zero, there is no limit for the account. To specify resource limits for an existing user without affecting existing privileges, use *Note `GRANT USAGE': grant. at the global level (`ON *.*') and name the limits to be changed. For example: GRANT USAGE ON *.* TO ... WITH MAX_QUERIES_PER_HOUR 500 MAX_UPDATES_PER_HOUR 100; Limits not specified retain their current values. For more information on restricting access to server resources, see *Note user-resources::. MySQL can check X509 certificate attributes in addition to the usual authentication that is based on the user name and password. To specify SSL-related options for a MySQL account, use the `REQUIRE' clause of the *Note `GRANT': grant. statement. (For background information on the use of SSL with MySQL, see *Note secure-connections::.) There are a number of different possibilities for limiting connection types for a given account: * `REQUIRE NONE' indicates that the account has no SSL or X509 requirements. This is the default if no SSL-related `REQUIRE' options are specified. Unencrypted connections are permitted if the user name and password are valid. However, encrypted connections can also be used, at the client's option, if the client has the proper certificate and key files. That is, the client need not specify any SSL command options, in which case the connection will be unencrypted. To use an encrypted connection, the client must specify either the `--ssl-ca' option, or all three of the `--ssl-ca', `--ssl-key', and `--ssl-cert' options. * The `REQUIRE SSL' option tells the server to permit only SSL-encrypted connections for the account. GRANT ALL PRIVILEGES ON test.* TO 'root'@'localhost' IDENTIFIED BY 'goodsecret' REQUIRE SSL; To connect, the client must specify the `--ssl-ca' option, and may additionally specify the `--ssl-key' and `--ssl-cert' options. * `REQUIRE X509' means that the client must have a valid certificate but that the exact certificate, issuer, and subject do not matter. The only requirement is that it should be possible to verify its signature with one of the CA certificates. GRANT ALL PRIVILEGES ON test.* TO 'root'@'localhost' IDENTIFIED BY 'goodsecret' REQUIRE X509; To connect, the client must specify the `--ssl-ca', `--ssl-key', and `--ssl-cert' options. This is also true for `ISSUER' and `SUBJECT' because those `REQUIRE' options imply `X509'. * `REQUIRE ISSUER 'ISSUER'' places the restriction on connection attempts that the client must present a valid X509 certificate issued by CA `'ISSUER''. If the client presents a certificate that is valid but has a different issuer, the server rejects the connection. Use of X509 certificates always implies encryption, so the `SSL' option is unnecessary in this case. GRANT ALL PRIVILEGES ON test.* TO 'root'@'localhost' IDENTIFIED BY 'goodsecret' REQUIRE ISSUER '/C=FI/ST=Some-State/L=Helsinki/ O=MySQL Finland AB/CN=Tonu Samuel/emailAddress=tonu@example.com'; The `'ISSUER'' value should be entered as a single string. *Note*: If MySQL is linked against a version of OpenSSL older than 0.9.6h, use `Email' rather than `emailAddress' in the `'ISSUER'' value. * `REQUIRE SUBJECT 'SUBJECT'' places the restriction on connection attempts that the client must present a valid X509 certificate containing the subject SUBJECT. If the client presents a certificate that is valid but has a different subject, the server rejects the connection. GRANT ALL PRIVILEGES ON test.* TO 'root'@'localhost' IDENTIFIED BY 'goodsecret' REQUIRE SUBJECT '/C=EE/ST=Some-State/L=Tallinn/ O=MySQL demo client certificate/ CN=Tonu Samuel/emailAddress=tonu@example.com'; The `'SUBJECT'' value should be entered as a single string. *Note*: Regarding `emailAddress', see the note in the description of `REQUIRE ISSUER'. * `REQUIRE CIPHER 'CIPHER'' is needed to ensure that ciphers and key lengths of sufficient strength are used. SSL itself can be weak if old algorithms using short encryption keys are used. Using this option, you can ask that a specific cipher method is used for a connection. GRANT ALL PRIVILEGES ON test.* TO 'root'@'localhost' IDENTIFIED BY 'goodsecret' REQUIRE CIPHER 'EDH-RSA-DES-CBC3-SHA'; The `SUBJECT', `ISSUER', and `CIPHER' options can be combined in the `REQUIRE' clause like this: GRANT ALL PRIVILEGES ON test.* TO 'root'@'localhost' IDENTIFIED BY 'goodsecret' REQUIRE SUBJECT '/C=EE/ST=Some-State/L=Tallinn/ O=MySQL demo client certificate/ CN=Tonu Samuel/emailAddress=tonu@example.com' AND ISSUER '/C=FI/ST=Some-State/L=Helsinki/ O=MySQL Finland AB/CN=Tonu Samuel/emailAddress=tonu@example.com' AND CIPHER 'EDH-RSA-DES-CBC3-SHA'; The order of the options does not matter, but no option can be specified twice. The `AND' keyword is optional between `REQUIRE' options. If you are using table, column, or routine privileges for even one user, the server examines table, column, and routine privileges for all users and this slows down MySQL a bit. Similarly, if you limit the number of queries, updates, or connections for any users, the server must monitor these values. * MySQL and Standard SQL Versions of *Note `GRANT': grant. * The biggest differences between the MySQL and standard SQL versions of *Note `GRANT': grant. are: * MySQL associates privileges with the combination of a host name and user name and not with only a user name. * Standard SQL does not have global or database-level privileges, nor does it support all the privilege types that MySQL supports. * MySQL does not support the standard SQL `UNDER' privilege. * Standard SQL privileges are structured in a hierarchical manner. If you remove a user, all privileges the user has been granted are revoked. This is also true in MySQL if you use *Note `DROP USER': drop-user. See *Note drop-user::. * In standard SQL, when you drop a table, all privileges for the table are revoked. In standard SQL, when you revoke a privilege, all privileges that were granted based on that privilege are also revoked. In MySQL, privileges can be dropped only with explicit *Note `DROP USER': drop-user. or *Note `REVOKE': revoke. statements or by manipulating the MySQL grant tables directly. * In MySQL, it is possible to have the `INSERT' privilege for only some of the columns in a table. In this case, you can still execute *Note `INSERT': insert. statements on the table, provided that you insert values only for those columns for which you have the `INSERT' privilege. The omitted columns are set to their implicit default values if strict SQL mode is not enabled. In strict mode, the statement is rejected if any of the omitted columns have no default value. (Standard SQL requires you to have the `INSERT' privilege on all columns.) *Note server-sql-mode::, discusses strict mode. *Note data-type-defaults::, discusses implicit default values.  File: manual.info, Node: rename-user, Next: revoke, Prev: grant, Up: account-management-sql 13.4.1.4 `RENAME USER' Syntax ............................. RENAME USER OLD_USER TO NEW_USER [, OLD_USER TO NEW_USER] ... The *Note `RENAME USER': rename-user. statement renames existing MySQL accounts. To use it, you must have the global `CREATE USER' privilege or the `UPDATE' privilege for the `mysql' database. An error occurs if any old account does not exist or any new account exists. Each account name uses the format described in *Note account-names::. For example: RENAME USER 'jeffrey'@'localhost' TO 'jeff'@'127.0.0.1'; If you specify only the user name part of the account name, a host name part of `'%'' is used. *Note `RENAME USER': rename-user. causes the privileges held by the old user to be those held by the new user. However, *Note `RENAME USER': rename-user. does not automatically drop or invalidate databases or objects within them that the old user created. This includes stored programs or views for which the `DEFINER' attribute names the old user. Attempts to access such objects may produce an error if they execute in definer security context. (For information about security context, see *Note stored-programs-security::.) The privilege changes take effect as indicated in *Note privilege-changes::.  File: manual.info, Node: revoke, Next: set-password, Prev: rename-user, Up: account-management-sql 13.4.1.5 `REVOKE' Syntax ........................ REVOKE PRIV_TYPE [(COLUMN_LIST)] [, PRIV_TYPE [(COLUMN_LIST)]] ... ON [OBJECT_TYPE] PRIV_LEVEL FROM USER [, USER] ... REVOKE ALL PRIVILEGES, GRANT OPTION FROM USER [, USER] ... The *Note `REVOKE': revoke. statement enables system administrators to revoke privileges from MySQL accounts. Each account name uses the format described in *Note account-names::. For example: REVOKE INSERT ON *.* FROM 'jeffrey'@'localhost'; If you specify only the user name part of the account name, a host name part of `'%'' is used. For details on the levels at which privileges exist, the permissible PRIV_TYPE and PRIV_LEVEL values, and the syntax for specifying users and passwords, see *Note grant:: To use the first *Note `REVOKE': revoke. syntax, you must have the `GRANT OPTION' privilege, and you must have the privileges that you are revoking. To revoke all privileges, use the second syntax, which drops all global, database, table, column, and routine privileges for the named user or users: REVOKE ALL PRIVILEGES, GRANT OPTION FROM USER [, USER] ... To use this *Note `REVOKE': revoke. syntax, you must have the global `CREATE USER' privilege or the `UPDATE' privilege for the `mysql' database. *Note `REVOKE': revoke. removes privileges, but does not drop `mysql.user' table entries. To remove a user account entirely, use *Note `DROP USER': drop-user. (see *Note drop-user::) or *Note `DELETE': delete. If the grant tables hold privilege rows that contain mixed-case database or table names and the `lower_case_table_names' system variable is set to a nonzero value, *Note `REVOKE': revoke. cannot be used to revoke these privileges. It will be necessary to manipulate the grant tables directly. (*Note `GRANT': grant. will not create such rows when `lower_case_table_names' is set, but such rows might have been created prior to setting the variable.) To verify an account's privileges after a *Note `REVOKE': revoke. operation, use *Note `SHOW GRANTS': show-grants. See *Note show-grants::.  File: manual.info, Node: set-password, Prev: revoke, Up: account-management-sql 13.4.1.6 `SET PASSWORD' Syntax .............................. SET PASSWORD [FOR USER] = { PASSWORD('SOME PASSWORD') | OLD_PASSWORD('SOME PASSWORD') | 'ENCRYPTED PASSWORD' } The *Note `SET PASSWORD': set-password. statement assigns a password to an existing MySQL user account. If the password is specified using the `PASSWORD()' or `OLD_PASSWORD()' function, the literal text of the password should be given. If the password is specified without using either function, the password should be the already-encrypted password value as returned by `PASSWORD()'. With no `FOR' clause, this statement sets the password for the current user. Any client that has connected to the server using a nonanonymous account can change the password for that account. In MySQL 5.1 and later, when the `read_only' system variable is enabled, the `SUPER' privilege is required to use *Note `SET PASSWORD': set-password. With a `FOR' clause, this statement sets the password for a specific account on the current server host. Only clients that have the *Note `UPDATE': update. privilege for the `mysql' database can do this. The USER value should be given in `USER_NAME@HOST_NAME' format, where USER_NAME and HOST_NAME are exactly as they are listed in the `User' and `Host' columns of the `mysql.user' table entry. For example, if you had an entry with `User' and `Host' column values of `'bob'' and `'%.loc.gov'', you would write the statement like this: SET PASSWORD FOR 'bob'@'%.loc.gov' = PASSWORD('NEWPASS'); That is equivalent to the following statements: UPDATE mysql.user SET Password=PASSWORD('NEWPASS') WHERE User='bob' AND Host='%.loc.gov'; FLUSH PRIVILEGES; Another way to set the password is to use *Note `GRANT': grant.: GRANT USAGE ON *.* TO 'bob'@'%.loc.gov' IDENTIFIED BY 'NEWPASS'; *Important*: *Note `SET PASSWORD': set-password. may be recorded in server logs or in a history file such as `~/.mysql_history', which means that plaintext passwords may be read by anyone having read access to that information. See *Note password-security::. *Note*: If you are connecting to a MySQL 4.1 or later server using a pre-4.1 client program, do not use the preceding *Note `SET PASSWORD': set-password. or *Note `UPDATE': update. statement without reading *Note password-hashing::, first. The password format changed in MySQL 4.1, and under certain circumstances it is possible that if you change your password, you might not be able to connect to the server afterward. To see which account the server authenticated you as, invoke the `CURRENT_USER()' function. For more information about setting passwords, see *Note assigning-passwords::  File: manual.info, Node: table-maintenance-sql, Next: plugin-sql, Prev: account-management-sql, Up: sql-syntax-server-administration 13.4.2 Table Maintenance Statements ----------------------------------- * Menu: * analyze-table:: `ANALYZE TABLE' Syntax * backup-table:: `BACKUP TABLE' Syntax * check-table:: `CHECK TABLE' Syntax * checksum-table:: `CHECKSUM TABLE' Syntax * optimize-table:: `OPTIMIZE TABLE' Syntax * repair-table:: `REPAIR TABLE' Syntax * restore-table:: `RESTORE TABLE' Syntax  File: manual.info, Node: analyze-table, Next: backup-table, Prev: table-maintenance-sql, Up: table-maintenance-sql 13.4.2.1 `ANALYZE TABLE' Syntax ............................... ANALYZE [NO_WRITE_TO_BINLOG | LOCAL] TABLE TBL_NAME [, TBL_NAME] ... *Note `ANALYZE TABLE': analyze-table. analyzes and stores the key distribution for a table. During the analysis, the table is locked with a read lock for `MyISAM' and `InnoDB'. This statement works with `MyISAM', `InnoDB', and `NDB' tables. For `MyISAM' tables, this statement is equivalent to using *Note `myisamchk --analyze': myisamchk. For more information on how the analysis works within `InnoDB', see *Note innodb-restrictions::. MySQL uses the stored key distribution to decide the order in which tables should be joined when you perform a join on something other than a constant. In addition, key distributions can be used when deciding which indexes to use for a specific table within a query. This statement requires `SELECT' and `INSERT' privileges for the table. Beginning with MySQL 5.1.27, *Note `ANALYZE TABLE': analyze-table. is also supported for partitioned tables. Also beginning with MySQL 5.1.27, you can use `ALTER TABLE ... ANALYZE PARTITION' to analyze one or more partitions; for more information, see *Note alter-table::, and *Note partitioning-maintenance::. *Note `ANALYZE TABLE': analyze-table. returns a result set with the following columns. Column Value `Table' The table name `Op' Always `analyze' `Msg_type' `status', `error', `info', `note', or `warning' `Msg_text' An informational message You can check the stored key distribution with the *Note `SHOW INDEX': show-index. statement. See *Note show-index::. If the table has not changed since the last *Note `ANALYZE TABLE': analyze-table. statement, the table is not analyzed again. By default, *Note `ANALYZE TABLE': analyze-table. statements are written to the binary log so that they will be replicated to replication slaves. Logging can be suppressed with the optional `NO_WRITE_TO_BINLOG' keyword or its alias `LOCAL'.  File: manual.info, Node: backup-table, Next: check-table, Prev: analyze-table, Up: table-maintenance-sql 13.4.2.2 `BACKUP TABLE' Syntax .............................. BACKUP TABLE TBL_NAME [, TBL_NAME] ... TO '/PATH/TO/BACKUP/DIRECTORY' *Note*: This statement is deprecated and is removed in MySQL 5.5. As an alternative, *Note `mysqldump': mysqldump. or *Note `mysqlhotcopy': mysqlhotcopy. can be used instead. *Note `BACKUP TABLE': backup-table. copies to the backup directory the minimum number of table files needed to restore the table, after flushing any buffered changes to disk. The statement works only for `MyISAM' tables. It copies the `.frm' definition and `.MYD' data files. The `.MYI' index file can be rebuilt from those two files. The directory should be specified as a full path name. To restore the table, use *Note `RESTORE TABLE': restore-table. During the backup, a read lock is held for each table, one at time, as they are being backed up. If you want to back up several tables as a snapshot (preventing any of them from being changed during the backup operation), issue a *Note `LOCK TABLES': lock-tables. statement first, to obtain a read lock for all tables in the group. *Note `BACKUP TABLE': backup-table. returns a result set with the following columns. Column Value `Table' The table name `Op' Always `backup' `Msg_type' `status', `error', `info', `note', or `warning' `Msg_text' An informational message  File: manual.info, Node: check-table, Next: checksum-table, Prev: backup-table, Up: table-maintenance-sql 13.4.2.3 `CHECK TABLE' Syntax ............................. CHECK TABLE TBL_NAME [, TBL_NAME] ... [OPTION] ... OPTION = {FOR UPGRADE | QUICK | FAST | MEDIUM | EXTENDED | CHANGED} *Note `CHECK TABLE': check-table. checks a table or tables for errors. *Note `CHECK TABLE': check-table. works for `MyISAM', `InnoDB', and `ARCHIVE' tables. Starting with MySQL 5.1.9, *Note `CHECK TABLE': check-table. is also valid for `CSV' tables, see *Note csv-storage-engine::. For `MyISAM' tables, the key statistics are updated as well. *Note `CHECK TABLE': check-table. can also check views for problems, such as tables that are referenced in the view definition that no longer exist. Beginning with MySQL 5.1.27, *Note `CHECK TABLE': check-table. is also supported for partitioned tables. Also beginning with MySQL 5.1.27, you can use `ALTER TABLE ... CHECK PARTITION' to check one or more partitions; for more information, see *Note alter-table::, and *Note partitioning-maintenance::. *Note `CHECK TABLE': check-table. returns a result set with the following columns. Column Value `Table' The table name `Op' Always `check' `Msg_type' `status', `error', `info', or `warning' `Msg_text' An informational message Note that the statement might produce many rows of information for each checked table. The last row has a `Msg_type' value of `status' and the `Msg_text' normally should be `OK'. If you don't get `OK', or `Table is already up to date' you should normally run a repair of the table. See *Note myisam-table-maintenance::. `Table is already up to date' means that the storage engine for the table indicated that there was no need to check the table. The `FOR UPGRADE' option checks whether the named tables are compatible with the current version of MySQL. This option was added in MySQL 5.1.7. With `FOR UPGRADE', the server checks each table to determine whether there have been any incompatible changes in any of the table's data types or indexes since the table was created. If not, the check succeeds. Otherwise, if there is a possible incompatibility, the server runs a full check on the table (which might take some time). If the full check succeeds, the server marks the table's `.frm' file with the current MySQL version number. Marking the `.frm' file ensures that further checks for the table with the same version of the server will be fast. Incompatibilities might occur because the storage format for a data type has changed or because its sort order has changed. Our aim is to avoid these changes, but occasionally they are necessary to correct problems that would be worse than an incompatibility between releases. Currently, `FOR UPGRADE' discovers these incompatibilities: * The indexing order for end-space in *Note `TEXT': blob. columns for `InnoDB' and `MyISAM' tables changed between MySQL 4.1 and 5.0. * The storage method of the new *Note `DECIMAL': numeric-types. data type changed between MySQL 5.0.3 and 5.0.5. * As of MySQL 5.1.25, if your table was created by a different version of the MySQL server than the one you are currently running, `FOR UPGRADE' indicates that the table has an `.frm' file with an incompatible version. In this case, the result set returned by *Note `CHECK TABLE': check-table. contains a line with a `Msg_type' value of `error' and a `Msg_text' value of `Table upgrade required. Please do "REPAIR TABLE `TBL_NAME`" to fix it!' * Changes are sometimes made to character sets or collations that require table indexes to be rebuilt. For details about these changes and when `FOR UPGRADE' detects them, see *Note checking-table-incompatibilities::. The other check options that can be given are shown in the following table. These options are passed to the storage engine, which may use them or not. `MyISAM' uses them; they are ignored for `InnoDB' tables and views. Type Meaning `QUICK' Do not scan the rows to check for incorrect links. `FAST' Check only tables that have not been closed properly. `CHANGED' Check only tables that have been changed since the last check or that have not been closed properly. `MEDIUM' Scan rows to verify that deleted links are valid. This also calculates a key checksum for the rows and verifies this with a calculated checksum for the keys. `EXTENDED' Do a full key lookup for all keys for each row. This ensures that the table is 100% consistent, but takes a long time. If none of the options `QUICK', `MEDIUM', or `EXTENDED' are specified, the default check type for dynamic-format `MyISAM' tables is `MEDIUM'. This has the same result as running *Note `myisamchk --medium-check TBL_NAME': myisamchk. on the table. The default check type also is `MEDIUM' for static-format `MyISAM' tables, unless `CHANGED' or `FAST' is specified. In that case, the default is `QUICK'. The row scan is skipped for `CHANGED' and `FAST' because the rows are very seldom corrupted. You can combine check options, as in the following example that does a quick check on the table to determine whether it was closed properly: CHECK TABLE test_table FAST QUICK; *Note*: In some cases, *Note `CHECK TABLE': check-table. changes the table. This happens if the table is marked as `corrupted' or `not closed properly' but *Note `CHECK TABLE': check-table. does not find any problems in the table. In this case, *Note `CHECK TABLE': check-table. marks the table as okay. If a table is corrupted, it is most likely that the problem is in the indexes and not in the data part. All of the preceding check types check the indexes thoroughly and should thus find most errors. If you just want to check a table that you assume is okay, you should use no check options or the `QUICK' option. The latter should be used when you are in a hurry and can take the very small risk that `QUICK' does not find an error in the data file. (In most cases, under normal usage, MySQL should find any error in the data file. If this happens, the table is marked as `corrupted' and cannot be used until it is repaired.) `FAST' and `CHANGED' are mostly intended to be used from a script (for example, to be executed from `cron') if you want to check tables from time to time. In most cases, `FAST' is to be preferred over `CHANGED'. (The only case when it is not preferred is when you suspect that you have found a bug in the `MyISAM' code.) `EXTENDED' is to be used only after you have run a normal check but still get strange errors from a table when MySQL tries to update a row or find a row by key. This is very unlikely if a normal check has succeeded. Use of *Note `CHECK TABLE ... EXTENDED': check-table. might influence the execution plan generated by the query optimizer. Some problems reported by *Note `CHECK TABLE': check-table. cannot be corrected automatically: * `Found row where the auto_increment column has the value 0'. This means that you have a row in the table where the `AUTO_INCREMENT' index column contains the value 0. (It is possible to create a row where the `AUTO_INCREMENT' column is 0 by explicitly setting the column to 0 with an *Note `UPDATE': update. statement.) This is not an error in itself, but could cause trouble if you decide to dump the table and restore it or do an *Note `ALTER TABLE': alter-table. on the table. In this case, the `AUTO_INCREMENT' column changes value according to the rules of `AUTO_INCREMENT' columns, which could cause problems such as a duplicate-key error. To get rid of the warning, simply execute an *Note `UPDATE': update. statement to set the column to some value other than 0. * If *Note `CHECK TABLE': check-table. finds a problem for an `InnoDB' table, the server shuts down to prevent error propagation. Details of the error will be written to the error log.  File: manual.info, Node: checksum-table, Next: optimize-table, Prev: check-table, Up: table-maintenance-sql 13.4.2.4 `CHECKSUM TABLE' Syntax ................................ CHECKSUM TABLE TBL_NAME [, TBL_NAME] ... [ QUICK | EXTENDED ] *Note `CHECKSUM TABLE': checksum-table. reports a table checksum. With `QUICK', the live table checksum is reported if it is available, or `NULL' otherwise. This is very fast. A live checksum is enabled by specifying the `CHECKSUM=1' table option when you create the table; currently, this is supported only for `MyISAM' tables. See *Note create-table::. With `EXTENDED', the entire table is read row by row and the checksum is calculated. This can be very slow for large tables. If neither `QUICK' nor `EXTENDED' is specified, MySQL returns a live checksum if the table storage engine supports it and scans the table otherwise. For a nonexistent table, *Note `CHECKSUM TABLE': checksum-table. returns `NULL' and generates a warning. The checksum value depends on the table row format. If the row format changes, the checksum also changes. For example, the storage format for *Note `VARCHAR': char. changed between MySQL 4.1 and 5.0, so if a 4.1 table is upgraded to MySQL 5.0, the checksum value may change. *Important*: If the checksums for two tables are different, then it is almost certain that the tables are different in some way. However, because the hashing function used by *Note `CHECKSUM TABLE': checksum-table. is not guaranteed to be collision-free, there is a slight chance that two tables which are not identical can produce the same checksum.  File: manual.info, Node: optimize-table, Next: repair-table, Prev: checksum-table, Up: table-maintenance-sql 13.4.2.5 `OPTIMIZE TABLE' Syntax ................................ OPTIMIZE [NO_WRITE_TO_BINLOG | LOCAL] TABLE TBL_NAME [, TBL_NAME] ... *Note `OPTIMIZE TABLE': optimize-table. should be used if you have deleted a large part of a table or if you have made many changes to a table with variable-length rows (tables that have *Note `VARCHAR': char, *Note `VARBINARY': binary-varbinary, *Note `BLOB': blob, or *Note `TEXT': blob. columns). Deleted rows are maintained in a linked list and subsequent *Note `INSERT': insert. operations reuse old row positions. You can use *Note `OPTIMIZE TABLE': optimize-table. to reclaim the unused space and to defragment the data file. After extensive changes to a table, this statement may also improve performance of statements that use the table, sometimes significantly. This statement requires `SELECT' and `INSERT' privileges for the table. Beginning with MySQL 5.1.27, *Note `OPTIMIZE TABLE': optimize-table. is also supported for partitioned tables. Also beginning with MySQL 5.1.27, you can use `ALTER TABLE ... OPTIMIZE PARTITION' to optimize one or more partitions; for more information, see *Note alter-table::, and *Note partitioning-maintenance::. *Note `OPTIMIZE TABLE': optimize-table. works for `MyISAM', `InnoDB', and `ARCHIVE' tables. Beginning with MySQL Cluster NDB 6.3.7, *Note `OPTIMIZE TABLE': optimize-table. is also supported for dynamic columns of in-memory *Note `NDBCLUSTER': mysql-cluster. tables. It does not work for Disk Data tables. The performance of `OPTIMIZE' on Cluster tables can be tuned by adjusting the value of the `ndb_optimization_delay' system variable, which controls the number of milliseconds to wait between processing batches of rows by *Note `OPTIMIZE TABLE': optimize-table. See *Note mysql-cluster-limitations-resolved::, for more information. *Note `OPTIMIZE TABLE': optimize-table. is not supported for tables using other storage engines except as noted previously. Beginning with MySQL Cluster NDB 6.3.8, *Note `OPTIMIZE TABLE': optimize-table. can be interrupted by (for example) killing the SQL thread performing the `OPTIMIZE' operation. For `MyISAM' tables, *Note `OPTIMIZE TABLE': optimize-table. works as follows: 1. If the table has deleted or split rows, repair the table. 2. If the index pages are not sorted, sort them. 3. If the table's statistics are not up to date (and the repair could not be accomplished by sorting the index), update them. For `InnoDB' tables, *Note `OPTIMIZE TABLE': optimize-table. is mapped to *Note `ALTER TABLE': alter-table, which rebuilds the table to update index statistics and free unused space in the clustered index. Beginning with MySQL 5.1.27, this is displayed in the output of *Note `OPTIMIZE TABLE': optimize-table. when you run it on an `InnoDB' table, as shown here: mysql> OPTIMIZE TABLE foo; +----------+----------+----------+-------------------------------------------------------------------+ | Table | Op | Msg_type | Msg_text | +----------+----------+----------+-------------------------------------------------------------------+ | test.foo | optimize | note | Table does not support optimize, doing recreate + analyze instead | | test.foo | optimize | status | OK | +----------+----------+----------+-------------------------------------------------------------------+ You can make *Note `OPTIMIZE TABLE': optimize-table. work on other storage engines by starting *Note `mysqld': mysqld. with the `--skip-new' or `--safe-mode' option. In this case, *Note `OPTIMIZE TABLE': optimize-table. is just mapped to *Note `ALTER TABLE': alter-table. *Note `OPTIMIZE TABLE': optimize-table. returns a result set with the following columns. Column Value `Table' The table name `Op' Always `optimize' `Msg_type' `status', `error', `info', `note', or `warning' `Msg_text' An informational message Note that MySQL locks the table during the time *Note `OPTIMIZE TABLE': optimize-table. is running. By default, *Note `OPTIMIZE TABLE': optimize-table. statements are written to the binary log so that they will be replicated to replication slaves. Logging can be suppressed with the optional `NO_WRITE_TO_BINLOG' keyword or its alias `LOCAL'. *Note `OPTIMIZE TABLE': optimize-table. does not sort R-tree indexes, such as spatial indexes on `POINT' columns. (Bug#23578)  File: manual.info, Node: repair-table, Next: restore-table, Prev: optimize-table, Up: table-maintenance-sql 13.4.2.6 `REPAIR TABLE' Syntax .............................. REPAIR [NO_WRITE_TO_BINLOG | LOCAL] TABLE TBL_NAME [, TBL_NAME] ... [QUICK] [EXTENDED] [USE_FRM] *Note `REPAIR TABLE': repair-table. repairs a possibly corrupted table. By default, it has the same effect as *Note `myisamchk --recover TBL_NAME': myisamchk. *Note `REPAIR TABLE': repair-table. works for `MyISAM' and for `ARCHIVE' tables. Starting with MySQL 5.1.9, `REPAIR' is also valid for `CSV' tables. See *Note myisam-storage-engine::, and *Note archive-storage-engine::, and *Note csv-storage-engine:: This statement requires `SELECT' and `INSERT' privileges for the table. Beginning with MySQL 5.1.27, *Note `REPAIR TABLE': repair-table. is also supported for partitioned tables. However, the `USE_FRM' option cannot be used with this statement on a partitioned table. Also beginning with MySQL 5.1.27, you can use `ALTER TABLE ... REPAIR PARTITION' to repair one or more partitions; for more information, see *Note alter-table::, and *Note partitioning-maintenance::. Normally, you should never have to run *Note `REPAIR TABLE': repair-table. However, if disaster strikes, this statement is very likely to get back all your data from a `MyISAM' table. If your tables become corrupted often, you should try to find the reason for it, to eliminate the need to use *Note `REPAIR TABLE': repair-table. See *Note crashing::, and *Note myisam-table-problems::. *Caution*: It is best to make a backup of a table before performing a table repair operation; under some circumstances the operation might cause data loss. Possible causes include but are not limited to file system errors. See *Note backup-and-recovery::. *Warning*: If the server crashes during a *Note `REPAIR TABLE': repair-table. operation, it is essential after restarting it that you immediately execute another *Note `REPAIR TABLE': repair-table. statement for the table before performing any other operations on it. In the worst case, you might have a new clean index file without information about the data file, and then the next operation you perform could overwrite the data file. This is an unlikely but possible scenario that underscores the value of making a backup first. *Note `REPAIR TABLE': repair-table. returns a result set with the following columns. Column Value `Table' The table name `Op' Always `repair' `Msg_type' `status', `error', `info', `note', or `warning' `Msg_text' An informational message The *Note `REPAIR TABLE': repair-table. statement might produce many rows of information for each repaired table. The last row has a `Msg_type' value of `status' and `Msg_test' normally should be `OK'. If you do not get `OK' for a `MyISAM' table, you should try repairing it with *Note `myisamchk --safe-recover': myisamchk. (*Note `REPAIR TABLE': repair-table. does not implement all the options of *Note `myisamchk': myisamchk.) With *Note `myisamchk --safe-recover': myisamchk, you can also use options that *Note `REPAIR TABLE': repair-table. does not support, such as `--max-record-length'. If you use the `QUICK' option, *Note `REPAIR TABLE': repair-table. tries to repair only the index file, and not the data file. This type of repair is like that done by *Note `myisamchk --recover --quick': myisamchk. If you use the `EXTENDED' option, MySQL creates the index row by row instead of creating one index at a time with sorting. This type of repair is like that done by *Note `myisamchk --safe-recover': myisamchk. The `USE_FRM' option is available for use if the `.MYI' index file is missing or if its header is corrupted. This option tells MySQL not to trust the information in the `.MYI' file header and to re-create it using information from the `.frm' file. This kind of repair cannot be done with *Note `myisamchk': myisamchk. *Note*: Use the `USE_FRM' option _only_ if you cannot use regular `REPAIR' modes! Telling the server to ignore the `.MYI' file makes important table metadata stored in the `.MYI' unavailable to the repair process, which can have deleterious consequences: * The current `AUTO_INCREMENT' value is lost. * The link to deleted records in the table is lost, which means that free space for deleted records will remain unoccupied thereafter. * The `.MYI' header indicates whether the table is compressed. If the server ignores this information, it cannot tell that a table is compressed and repair can cause change or loss of table contents. This means that `USE_FRM' should not be used with compressed tables. That should not be necessary, anyway: Compressed tables are read only, so they should not become corrupt. *Caution*: As of MySQL 5.1.25, if you use `USE_FRM' for a table that was created by a different version of the MySQL server than the one you are currently running, *Note `REPAIR TABLE': repair-table. will not attempt to repair the table. In this case, the result set returned by *Note `REPAIR TABLE': repair-table. contains a line with a `Msg_type' value of `error' and a `Msg_text' value of `Failed repairing incompatible .FRM file'. Prior to MySQL 5.1.25, _do not use_ `USE_FRM' if your table was created by a different version of the MySQL server. Doing so risks the loss of all rows in the table. It is particularly dangerous to use `USE_FRM' after the server returns this message: Table upgrade required. Please do "REPAIR TABLE `TBL_NAME`" or dump/reload to fix it! If `USE_FRM' is _not_ used, *Note `REPAIR TABLE': repair-table. checks the table to see whether an upgrade is required. If so, it performs the upgrade, following the same rules as *Note `CHECK TABLE ... FOR UPGRADE': check-table. See *Note check-table::, for more information. As of MySQL 5.1.25, *Note `REPAIR TABLE': repair-table. without `USE_FRM' upgrades the `.frm' file to the current version. By default, *Note `REPAIR TABLE': repair-table. statements are written to the binary log so that they will be replicated to replication slaves. Logging can be suppressed with the optional `NO_WRITE_TO_BINLOG' keyword or its alias `LOCAL'. *Important*: In the event that a table on the master becomes corrupted and you run *Note `REPAIR TABLE': repair-table. on it, any resulting changes to the original table are _not_ propagated to slaves. You may be able to increase *Note `REPAIR TABLE': repair-table. performance by setting certain system variables. See *Note repair-table-speed::.  File: manual.info, Node: restore-table, Prev: repair-table, Up: table-maintenance-sql 13.4.2.7 `RESTORE TABLE' Syntax ............................... RESTORE TABLE TBL_NAME [, TBL_NAME] ... FROM '/PATH/TO/BACKUP/DIRECTORY' *Note*: This statement is deprecated and is removed in MySQL 5.5. *Note `RESTORE TABLE': restore-table. restores the table or tables from a backup that was made with *Note `BACKUP TABLE': backup-table. The directory should be specified as a full path name. Existing tables are not overwritten; if you try to restore over an existing table, an error occurs. Just as for *Note `BACKUP TABLE': backup-table, *Note `RESTORE TABLE': restore-table. currently works only for `MyISAM' tables. Restored tables are not replicated from master to slave. The backup for each table consists of its `.frm' format file and `.MYD' data file. The restore operation restores those files, and then uses them to rebuild the `.MYI' index file. Restoring takes longer than backing up due to the need to rebuild the indexes. The more indexes the table has, the longer it takes. *Note `RESTORE TABLE': restore-table. returns a result set with the following columns. Column Value `Table' The table name `Op' Always `restore' `Msg_type' `status', `error', `info', or `warning' `Msg_text' An informational message  File: manual.info, Node: plugin-sql, Next: set-option, Prev: table-maintenance-sql, Up: sql-syntax-server-administration 13.4.3 Plugin and User-Defined Function Statements -------------------------------------------------- * Menu: * create-function-udf:: `CREATE FUNCTION' Syntax for User-Defined Functions * drop-function-udf:: `DROP FUNCTION' Syntax * install-plugin:: `INSTALL PLUGIN' Syntax * uninstall-plugin:: `UNINSTALL PLUGIN' Syntax  File: manual.info, Node: create-function-udf, Next: drop-function-udf, Prev: plugin-sql, Up: plugin-sql 13.4.3.1 `CREATE FUNCTION' Syntax for User-Defined Functions ............................................................ CREATE [AGGREGATE] FUNCTION FUNCTION_NAME RETURNS {STRING|INTEGER|REAL|DECIMAL} SONAME SHARED_LIBRARY_NAME A user-defined function (UDF) is a way to extend MySQL with a new function that works like a native (built-in) MySQL function such as `ABS()' or `CONCAT()'. FUNCTION_NAME is the name that should be used in SQL statements to invoke the function. The `RETURNS' clause indicates the type of the function's return value. *Note `DECIMAL': numeric-types. is a legal value after `RETURNS', but currently *Note `DECIMAL': numeric-types. functions return string values and should be written like `STRING' functions. SHARED_LIBRARY_NAME is the basename of the shared object file that contains the code that implements the function. The file must be located in the plugin directory. This directory is given by the value of the `plugin_dir' system variable. *Note*: This is a change in MySQL 5.1. For earlier versions of MySQL, the shared object can be located in any directory that is searched by your system's dynamic linker. For more information, see *Note udf-compiling::. To create a function, you must have the `INSERT' privilege for the `mysql' database. This is necessary because *Note `CREATE FUNCTION': create-function. adds a row to the `mysql.func' system table that records the function's name, type, and shared library name. If you do not have this table, you should run the *Note `mysql_upgrade': mysql-upgrade. command to create it. See *Note mysql-upgrade::. An active function is one that has been loaded with *Note `CREATE FUNCTION': create-function. and not removed with *Note `DROP FUNCTION': drop-function. All active functions are reloaded each time the server starts, unless you start *Note `mysqld': mysqld. with the `--skip-grant-tables' option. In this case, UDF initialization is skipped and UDFs are unavailable. For instructions on writing user-defined functions, see *Note adding-udf::. For the UDF mechanism to work, functions must be written in C or C++ (or another language that can use C calling conventions), your operating system must support dynamic loading and you must have compiled *Note `mysqld': mysqld. dynamically (not statically). An `AGGREGATE' function works exactly like a native MySQL aggregate (summary) function such as `SUM' or `COUNT()'. For `AGGREGATE' to work, your `mysql.func' table must contain a `type' column. If your `mysql.func' table does not have this column, you should run the *Note `mysql_upgrade': mysql-upgrade. program to create it (see *Note mysql-upgrade::). *Note*: To upgrade the shared library associated with a UDF, issue a *Note `DROP FUNCTION': drop-function. statement, upgrade the shared library, and then issue a *Note `CREATE FUNCTION': create-function. statement. If you upgrade the shared library first and then use *Note `DROP FUNCTION': drop-function, the server may crash.  File: manual.info, Node: drop-function-udf, Next: install-plugin, Prev: create-function-udf, Up: plugin-sql 13.4.3.2 `DROP FUNCTION' Syntax ............................... DROP FUNCTION FUNCTION_NAME This statement drops the user-defined function (UDF) named FUNCTION_NAME. To drop a function, you must have the `DELETE' privilege for the `mysql' database. This is because *Note `DROP FUNCTION': drop-function. removes a row from the `mysql.func' system table that records the function's name, type, and shared library name. *Note*: To upgrade the shared library associated with a UDF, issue a *Note `DROP FUNCTION': drop-function. statement, upgrade the shared library, and then issue a *Note `CREATE FUNCTION': create-function. statement. If you upgrade the shared library first and then use *Note `DROP FUNCTION': drop-function, the server may crash. *Note `DROP FUNCTION': drop-function. is also used to drop stored functions (see *Note drop-procedure::).  File: manual.info, Node: install-plugin, Next: uninstall-plugin, Prev: drop-function-udf, Up: plugin-sql 13.4.3.3 `INSTALL PLUGIN' Syntax ................................ INSTALL PLUGIN PLUGIN_NAME SONAME 'SHARED_LIBRARY_NAME' This statement installs a server plugin. It requires the `INSERT privilege' for the `mysql.plugin' table. PLUGIN_NAME is the name of the plugin as defined in the plugin descriptor structure contained in the library file (see *Note plugin-data-structures::). Plugin names are not case sensitive. For maximal compatibility, plugin names should be limited to ASCII letters, digits, and underscore because they are used in C source files, shell command lines, M4 and Bourne shell scripts, and SQL environments. SHARED_LIBRARY_NAME is the name of the shared library that contains the plugin code. The name includes the file name extension (for example, `libmyplugin.so', `libmyplugin.dll', or `libmyplugin.dylib'). The shared library must be located in the plugin directory (the directory named by the `plugin_dir' system variable). The library must be in the plugin directory itself, not in a subdirectory. By default, `plugin_dir' is the `plugin' directory under the directory named by the `pkglibdir' configuration variable, but it can be changed by setting the value of `plugin_dir' at server startup. For example, set its value in a `my.cnf' file: [mysqld] plugin_dir=/PATH/TO/PLUGIN/DIRECTORY If the value of `plugin_dir' is a relative path name, it is taken to be relative to the MySQL base directory (the value of the `basedir' system variable). *Note `INSTALL PLUGIN': install-plugin. loads and initializes the plugin code to make the plugin available for use. A plugin is initialized by executing its initialization function, which handles any setup that the plugin must perform before it can be used. When the server shuts down, it executes the deinitialization function for each plugin that is loaded so that the plugin has a change to perform any final cleanup. *Note `INSTALL PLUGIN': install-plugin. also registers the plugin by adding a line that indicates the plugin name and library file name to the `mysql.plugin' table. At server startup, the server loads and initializes any plugin that is listed in the `mysql.plugin' table. This means that a plugin is installed with *Note `INSTALL PLUGIN': install-plugin. only once, not every time the server starts. Plugin loading at startup does not occur if the server is started with the `--skip-grant-tables' option. A plugin library can contain multiple plugins. For each of them to be installed, use a separate *Note `INSTALL PLUGIN': install-plugin. statement. Each statement names a different plugin, but all of them specify the same library name. As of MySQL 5.1.33, *Note `INSTALL PLUGIN': install-plugin. causes the server to read option (`my.cnf') files just as during server startup. This enables the plugin to pick up any relevant options from those files. It is possible to add plugin options to an option file even before loading a plugin (if the `loose' prefix is used). It is also possible to uninstall a plugin, edit `my.cnf', and install the plugin again. Restarting the plugin this way enables it to the new option values without a server restart. Before MySQL 5.1.33, a plugin is started with each option set to its default value. For options that control individual plugin loading at server startup, see *Note server-plugin-loading::. If you need to load plugins for a single server startup when the `--skip-grant-tables' option is given (which tells the server not to read system tables), use the `--plugin-load' option. See *Note server-options::. To remove a plugin, use the *Note `UNINSTALL PLUGIN': uninstall-plugin. statement. For additional information about plugin loading, see *Note server-plugin-loading::. To see what plugins are installed, use the *Note `SHOW PLUGINS': show-plugins. statement or query the *Note `INFORMATION_SCHEMA.PLUGINS': plugins-table. table. If you recompile a plugin library and need to reinstall it, you can use either of the following methods: * Use *Note `UNINSTALL PLUGIN': uninstall-plugin. to uninstall all plugins in the library, install the new plugin library file in the plugin directory, and then use *Note `INSTALL PLUGIN': install-plugin. to install all plugins in the library. This procedure has the advantage that it can be used without stopping the server. However, if the plugin library contains many plugins, you must issue many *Note `INSTALL PLUGIN': install-plugin. and *Note `UNINSTALL PLUGIN': uninstall-plugin. statements. * Stop the server, install the new plugin library file in the plugin directory, and restart the server.  File: manual.info, Node: uninstall-plugin, Prev: install-plugin, Up: plugin-sql 13.4.3.4 `UNINSTALL PLUGIN' Syntax .................................. UNINSTALL PLUGIN PLUGIN_NAME This statement removes an installed server plugin. It requires the `DELETE' privilege for the `mysql.plugin' table. PLUGIN_NAME must be the name of some plugin that is listed in the `mysql.plugin' table. The server executes the plugin's deinitialization function and removes the row for the plugin from the `mysql.plugin' table, so that subsequent server restarts will not load and initialize the plugin. *Note `UNINSTALL PLUGIN': uninstall-plugin. does not remove the plugin's shared library file. You cannot uninstall a plugin if any table that uses it is open. Plugin removal has implications for the use of associated tables. For example, if a full-text parser plugin is associated with a `FULLTEXT' index on the table, uninstalling the plugin makes the table unusable. Any attempt to access the table results in an error. The table cannot even be opened, so you cannot drop an index for which the plugin is used. This means that uninstalling a plugin is something to do with care unless you do not care about the table contents. If you are uninstalling a plugin with no intention of reinstalling it later and you care about the table contents, you should dump the table with *Note `mysqldump': mysqldump. and remove the `WITH PARSER' clause from the dumped *Note `CREATE TABLE': create-table. statement so that you can reload the table later. If you do not care about the table, *Note `DROP TABLE': drop-table. can be used even if any plugins associated with the table are missing. For additional information about plugin loading, see *Note server-plugin-loading::.  File: manual.info, Node: set-option, Next: show, Prev: plugin-sql, Up: sql-syntax-server-administration 13.4.4 `SET' Syntax ------------------- SET VARIABLE_ASSIGNMENT [, VARIABLE_ASSIGNMENT] ... VARIABLE_ASSIGNMENT: USER_VAR_NAME = EXPR | [GLOBAL | SESSION] SYSTEM_VAR_NAME = EXPR | [@@global. | @@session. | @@]SYSTEM_VAR_NAME = EXPR The *Note `SET': set-option. statement assigns values to different types of variables that affect the operation of the server or your client. Older versions of MySQL employed `SET OPTION', but this syntax is deprecated in favor of *Note `SET': set-option. without `OPTION'. This section describes use of *Note `SET': set-option. for assigning values to system variables or user variables. For general information about these types of variables, see *Note server-system-variables::, and *Note user-variables::. System variables also can be set at server startup, as described in *Note using-system-variables::. Some variants of *Note `SET': set-option. syntax are used in other contexts: * `SET CHARACTER SET' and `SET NAMES' assign values to character set and collation variables associated with the connection to the server. `SET ONESHOT' is used for replication. These variants are described later in this section. * *Note `SET PASSWORD': set-password. assigns account passwords. See *Note set-password::. * *Note `SET TRANSACTION ISOLATION LEVEL': set-transaction. sets the isolation level for transaction processing. See *Note set-transaction::. * `SET' is used within stored routines to assign values to local routine variables. See *Note set-statement::. The following discussion shows the different *Note `SET': set-option. syntaxes that you can use to set variables. The examples use the `=' assignment operator, but you can also use the `:=' assignment operator for this purpose. A user variable is written as `@VAR_NAME' and can be set as follows: SET @VAR_NAME = EXPR; Many system variables are dynamic and can be changed while the server runs by using the *Note `SET': set-option. statement. For a list, see *Note dynamic-system-variables::. To change a system variable with *Note `SET': set-option, refer to it as VAR_NAME, optionally preceded by a modifier: * To indicate explicitly that a variable is a global variable, precede its name by `GLOBAL' or `@@global.'. The `SUPER' privilege is required to set global variables. * To indicate explicitly that a variable is a session variable, precede its name by `SESSION', `@@session.', or `@@'. Setting a session variable requires no special privilege, but a client can change only its own session variables, not those of any other client. * `LOCAL' and `@@local.' are synonyms for `SESSION' and `@@session.'. * If no modifier is present, *Note `SET': set-option. changes the session variable. A *Note `SET': set-option. statement can contain multiple variable assignments, separated by commas. If you set several system variables, the most recent `GLOBAL' or `SESSION' modifier in the statement is used for following variables that have no modifier specified. Examples: SET sort_buffer_size=10000; SET @@local.sort_buffer_size=10000; SET GLOBAL sort_buffer_size=1000000, SESSION sort_buffer_size=1000000; SET @@sort_buffer_size=1000000; SET @@global.sort_buffer_size=1000000, @@local.sort_buffer_size=1000000; The `@@VAR_NAME' syntax for system variables is supported for compatibility with some other database systems. If you change a session system variable, the value remains in effect until your session ends or until you change the variable to a different value. The change is not visible to other clients. If you change a global system variable, the value is remembered and used for new connections until the server restarts. (To make a global system variable setting permanent, you should set it in an option file.) The change is visible to any client that accesses that global variable. However, the change affects the corresponding session variable only for clients that connect after the change. The global variable change does not affect the session variable for any client that is currently connected (not even that of the client that issues the *Note `SET GLOBAL': set-option. statement). To prevent incorrect usage, MySQL produces an error if you use *Note `SET GLOBAL': set-option. with a variable that can only be used with *Note `SET SESSION': set-option. or if you do not specify `GLOBAL' (or `@@global.') when setting a global variable. To set a `SESSION' variable to the `GLOBAL' value or a `GLOBAL' value to the compiled-in MySQL default value, use the `DEFAULT' keyword. For example, the following two statements are identical in setting the session value of `max_join_size' to the global value: SET max_join_size=DEFAULT; SET @@session.max_join_size=@@global.max_join_size; Not all system variables can be set to `DEFAULT'. In such cases, use of `DEFAULT' results in an error. You can refer to the values of specific global or session system variables in expressions by using one of the `@@'-modifiers. For example, you can retrieve values in a *Note `SELECT': select. statement like this: SELECT @@global.sql_mode, @@session.sql_mode, @@sql_mode; When you refer to a system variable in an expression as `@@VAR_NAME' (that is, when you do not specify `@@global.' or `@@session.'), MySQL returns the session value if it exists and the global value otherwise. (This differs from `SET @@VAR_NAME = VALUE', which always refers to the session value.) *Note*: Some variables displayed by `SHOW VARIABLES' may not be available using `SELECT @@VAR_NAME' syntax; an `Unknown system variable' occurs. As a workaround in such cases, you can use `SHOW VARIABLES LIKE 'VAR_NAME''. Suffixes for specifying a value multiplier can be used when setting a variable at server startup, but not to set the value with *Note `SET': set-option. at runtime. On the other hand, with *Note `SET': set-option. you can assign a variable's value using an expression, which is not true when you set a variable at server startup. For example, the first of the following lines is legal at server startup, but the second is not: shell> mysql --max_allowed_packet=16M shell> mysql --max_allowed_packet=16*1024*1024 Conversely, the second of the following lines is legal at runtime, but the first is not: mysql> SET GLOBAL max_allowed_packet=16M; mysql> SET GLOBAL max_allowed_packet=16*1024*1024; To display system variables names and values, use the *Note `SHOW VARIABLES': show-variables. statement. (See *Note show-variables::.) The following list describes *Note `SET': set-option. options that have nonstandard syntax (that is, options that are not set with `NAME = VALUE' syntax). * `CHARACTER SET {CHARSET_NAME | DEFAULT}' This maps all strings from and to the client with the given mapping. You can add new mappings by editing `sql/convert.cc' in the MySQL source distribution. `SET CHARACTER SET' sets three session system variables: `character_set_client' and `character_set_results' are set to the given character set, and `character_set_connection' to the value of `character_set_database'. See *Note charset-connection::. The default mapping can be restored by using the value `DEFAULT'. The default depends on the server configuration. `ucs2' cannot be used as a client character set, which means that it does not work for `SET CHARACTER SET'. * `NAMES {'CHARSET_NAME' [COLLATE 'COLLATION_NAME'] | DEFAULT}' `SET NAMES' sets the three session system variables `character_set_client', `character_set_connection', and `character_set_results' to the given character set. Setting `character_set_connection' to `charset_name' also sets `collation_connection' to the default collation for `charset_name'. The optional `COLLATE' clause may be used to specify a collation explicitly. See *Note charset-connection::. The default mapping can be restored by using a value of `DEFAULT'. The default depends on the server configuration. `ucs2' cannot be used as a client character set, which means that it does not work for `SET NAMES'. * `ONE_SHOT' This option is a modifier, not a variable. It is _only_ for internal use for replication: *Note `mysqlbinlog': mysqlbinlog. uses `SET ONE_SHOT' to modify temporarily the values of character set, collation, and time zone variables to reflect at rollforward what they were originally. `ONE_SHOT' is for internal use only and is deprecated for MySQL 5.0 and up. `ONE_SHOT' is intended for use only with the permitted set of variables. With other variables, an error occurs: mysql> SET ONE_SHOT max_allowed_packet = 1; ERROR 1382 (HY000): The 'SET ONE_SHOT' syntax is reserved for purposes internal to the MySQL server If `ONE_SHOT' is used with the permitted variables, it changes the variables as requested, but only for the next non-*Note `SET': set-option. statement. After that, the server resets all character set, collation, and time zone-related system variables to their previous values. Example: mysql> SET ONE_SHOT character_set_connection = latin5; mysql> SET ONE_SHOT collation_connection = latin5_turkish_ci; mysql> SHOW VARIABLES LIKE '%_connection'; +--------------------------+-------------------+ | Variable_name | Value | +--------------------------+-------------------+ | character_set_connection | latin5 | | collation_connection | latin5_turkish_ci | +--------------------------+-------------------+ mysql> SHOW VARIABLES LIKE '%_connection'; +--------------------------+-------------------+ | Variable_name | Value | +--------------------------+-------------------+ | character_set_connection | latin1 | | collation_connection | latin1_swedish_ci | +--------------------------+-------------------+  File: manual.info, Node: show, Next: other-administrative-sql, Prev: set-option, Up: sql-syntax-server-administration 13.4.5 `SHOW' Syntax -------------------- * Menu: * show-authors:: `SHOW AUTHORS' Syntax * show-binary-logs:: `SHOW BINARY LOGS' Syntax * show-binlog-events:: `SHOW BINLOG EVENTS' Syntax * show-character-set:: `SHOW CHARACTER SET' Syntax * show-collation:: `SHOW COLLATION' Syntax * show-columns:: `SHOW COLUMNS' Syntax * show-contributors:: `SHOW CONTRIBUTORS' Syntax * show-create-database:: `SHOW CREATE DATABASE' Syntax * show-create-event:: `SHOW CREATE EVENT' Syntax * show-create-function:: `SHOW CREATE FUNCTION' Syntax * show-create-procedure:: `SHOW CREATE PROCEDURE' Syntax * show-create-table:: `SHOW CREATE TABLE' Syntax * show-create-trigger:: `SHOW CREATE TRIGGER' Syntax * show-create-view:: `SHOW CREATE VIEW' Syntax * show-databases:: `SHOW DATABASES' Syntax * show-engine:: `SHOW ENGINE' Syntax * show-engines:: `SHOW ENGINES' Syntax * show-errors:: `SHOW ERRORS' Syntax * show-events:: `SHOW EVENTS' Syntax * show-function-code:: `SHOW FUNCTION CODE' Syntax * show-function-status:: `SHOW FUNCTION STATUS' Syntax * show-grants:: `SHOW GRANTS' Syntax * show-index:: `SHOW INDEX' Syntax * show-innodb-status:: `SHOW INNODB STATUS' Syntax * show-master-status:: `SHOW MASTER STATUS' Syntax * show-open-tables:: `SHOW OPEN TABLES' Syntax * show-plugins:: `SHOW PLUGINS' Syntax * show-privileges:: `SHOW PRIVILEGES' Syntax * show-procedure-code:: `SHOW PROCEDURE CODE' Syntax * show-procedure-status:: `SHOW PROCEDURE STATUS' Syntax * show-processlist:: `SHOW PROCESSLIST' Syntax * show-profile:: `SHOW PROFILE' Syntax * show-profiles:: `SHOW PROFILES' Syntax * show-scheduler-status:: `SHOW SCHEDULER STATUS' Syntax * show-slave-hosts:: `SHOW SLAVE HOSTS' Syntax * show-slave-status:: `SHOW SLAVE STATUS' Syntax * show-status:: `SHOW STATUS' Syntax * show-table-status:: `SHOW TABLE STATUS' Syntax * show-tables:: `SHOW TABLES' Syntax * show-triggers:: `SHOW TRIGGERS' Syntax * show-variables:: `SHOW VARIABLES' Syntax * show-warnings:: `SHOW WARNINGS' Syntax *Note `SHOW': show. has many forms that provide information about databases, tables, columns, or status information about the server. This section describes those following: SHOW AUTHORS SHOW {BINARY | MASTER} LOGS SHOW BINLOG EVENTS [IN 'LOG_NAME'] [FROM POS] [LIMIT [OFFSET,] ROW_COUNT] SHOW CHARACTER SET [LIKE_OR_WHERE] SHOW COLLATION [LIKE_OR_WHERE] SHOW [FULL] COLUMNS FROM TBL_NAME [FROM DB_NAME] [LIKE_OR_WHERE] SHOW CONTRIBUTORS SHOW CREATE DATABASE DB_NAME SHOW CREATE EVENT EVENT_NAME SHOW CREATE FUNCTION FUNC_NAME SHOW CREATE PROCEDURE PROC_NAME SHOW CREATE TABLE TBL_NAME SHOW CREATE TRIGGER TRIGGER_NAME SHOW CREATE VIEW VIEW_NAME SHOW DATABASES [LIKE_OR_WHERE] SHOW ENGINE ENGINE_NAME {STATUS | MUTEX} SHOW [STORAGE] ENGINES SHOW ERRORS [LIMIT [OFFSET,] ROW_COUNT] SHOW EVENTS SHOW FUNCTION CODE FUNC_NAME SHOW FUNCTION STATUS [LIKE_OR_WHERE] SHOW GRANTS FOR USER SHOW INDEX FROM TBL_NAME [FROM DB_NAME] SHOW INNODB STATUS SHOW MASTER STATUS SHOW OPEN TABLES [FROM DB_NAME] [LIKE_OR_WHERE] SHOW PLUGINS SHOW PROCEDURE CODE PROC_NAME SHOW PROCEDURE STATUS [LIKE_OR_WHERE] SHOW PRIVILEGES SHOW [FULL] PROCESSLIST SHOW PROFILE [TYPES] [FOR QUERY N] [OFFSET N] [LIMIT N] SHOW PROFILES SHOW SCHEDULER STATUS SHOW SLAVE HOSTS SHOW SLAVE STATUS SHOW [GLOBAL | SESSION] STATUS [LIKE_OR_WHERE] SHOW TABLE STATUS [FROM DB_NAME] [LIKE_OR_WHERE] SHOW [FULL] TABLES [FROM DB_NAME] [LIKE_OR_WHERE] SHOW TRIGGERS [FROM DB_NAME] [LIKE_OR_WHERE] SHOW [GLOBAL | SESSION] VARIABLES [LIKE_OR_WHERE] SHOW WARNINGS [LIMIT [OFFSET,] ROW_COUNT] LIKE_OR_WHERE: LIKE 'PATTERN' | WHERE EXPR If the syntax for a given *Note `SHOW': show. statement includes a `LIKE 'PATTERN'' part, `'PATTERN'' is a string that can contain the SQL ``%'' and ``_'' wildcard characters. The pattern is useful for restricting statement output to matching values. Several *Note `SHOW': show. statements also accept a `WHERE' clause that provides more flexibility in specifying which rows to display. See *Note extended-show::. Many MySQL APIs (such as PHP) enable you to treat the result returned from a *Note `SHOW': show. statement as you would a result set from a *Note `SELECT': select.; see *Note connectors-apis::, or your API documentation for more information. In addition, you can work in SQL with results from queries on tables in the `INFORMATION_SCHEMA' database, which you cannot easily do with results from *Note `SHOW': show. statements. See *Note information-schema::.  File: manual.info, Node: show-authors, Next: show-binary-logs, Prev: show, Up: show 13.4.5.1 `SHOW AUTHORS' Syntax .............................. SHOW AUTHORS The *Note `SHOW AUTHORS': show-authors. statement displays information about the people who work on MySQL. For each author, it displays `Name', `Location', and `Comment' values. This statement was added in MySQL 5.1.3.  File: manual.info, Node: show-binary-logs, Next: show-binlog-events, Prev: show-authors, Up: show 13.4.5.2 `SHOW BINARY LOGS' Syntax .................................. SHOW BINARY LOGS SHOW MASTER LOGS Lists the binary log files on the server. This statement is used as part of the procedure described in *Note purge-binary-logs::, that shows how to determine which logs can be purged. mysql> SHOW BINARY LOGS; +---------------+-----------+ | Log_name | File_size | +---------------+-----------+ | binlog.000015 | 724935 | | binlog.000016 | 733481 | +---------------+-----------+ *Note `SHOW MASTER LOGS': show-binary-logs. is equivalent to *Note `SHOW BINARY LOGS': show-binary-logs.  File: manual.info, Node: show-binlog-events, Next: show-character-set, Prev: show-binary-logs, Up: show 13.4.5.3 `SHOW BINLOG EVENTS' Syntax .................................... SHOW BINLOG EVENTS [IN 'LOG_NAME'] [FROM POS] [LIMIT [OFFSET,] ROW_COUNT] Shows the events in the binary log. If you do not specify `'LOG_NAME'', the first binary log is displayed. The `LIMIT' clause has the same syntax as for the *Note `SELECT': select. statement. See *Note select::. *Note*: Issuing a *Note `SHOW BINLOG EVENTS': show-binlog-events. with no `LIMIT' clause could start a very time- and resource-consuming process because the server returns to the client the complete contents of the binary log (which includes all statements executed by the server that modify data). As an alternative to *Note `SHOW BINLOG EVENTS': show-binlog-events, use the *Note `mysqlbinlog': mysqlbinlog. utility to save the binary log to a text file for later examination and analysis. See *Note mysqlbinlog::. *Note*: Some events relating to the setting of user and system variables are not included in the output from *Note `SHOW BINLOG EVENTS': show-binlog-events. To get complete coverage of events within a binary log, use *Note `mysqlbinlog': mysqlbinlog.  File: manual.info, Node: show-character-set, Next: show-collation, Prev: show-binlog-events, Up: show 13.4.5.4 `SHOW CHARACTER SET' Syntax .................................... SHOW CHARACTER SET [LIKE 'PATTERN' | WHERE EXPR] The *Note `SHOW CHARACTER SET': show-character-set. statement shows all available character sets. The `LIKE' clause, if present, indicates which character set names to match. The `WHERE' clause can be given to select rows using more general conditions, as discussed in *Note extended-show::. For example: mysql> SHOW CHARACTER SET LIKE 'latin%'; +---------+-----------------------------+-------------------+--------+ | Charset | Description | Default collation | Maxlen | +---------+-----------------------------+-------------------+--------+ | latin1 | cp1252 West European | latin1_swedish_ci | 1 | | latin2 | ISO 8859-2 Central European | latin2_general_ci | 1 | | latin5 | ISO 8859-9 Turkish | latin5_turkish_ci | 1 | | latin7 | ISO 8859-13 Baltic | latin7_general_ci | 1 | +---------+-----------------------------+-------------------+--------+ The `Maxlen' column shows the maximum number of bytes required to store one character.  File: manual.info, Node: show-collation, Next: show-columns, Prev: show-character-set, Up: show 13.4.5.5 `SHOW COLLATION' Syntax ................................ SHOW COLLATION [LIKE 'PATTERN' | WHERE EXPR] This statement lists collations supported by the server. By default, the output from *Note `SHOW COLLATION': show-collation. includes all available collations. The `LIKE' clause, if present, indicates which collation names to match. The `WHERE' clause can be given to select rows using more general conditions, as discussed in *Note extended-show::. For example: mysql> SHOW COLLATION LIKE 'latin1%'; +-------------------+---------+----+---------+----------+---------+ | Collation | Charset | Id | Default | Compiled | Sortlen | +-------------------+---------+----+---------+----------+---------+ | latin1_german1_ci | latin1 | 5 | | | 0 | | latin1_swedish_ci | latin1 | 8 | Yes | Yes | 0 | | latin1_danish_ci | latin1 | 15 | | | 0 | | latin1_german2_ci | latin1 | 31 | | Yes | 2 | | latin1_bin | latin1 | 47 | | Yes | 0 | | latin1_general_ci | latin1 | 48 | | | 0 | | latin1_general_cs | latin1 | 49 | | | 0 | | latin1_spanish_ci | latin1 | 94 | | | 0 | +-------------------+---------+----+---------+----------+---------+ The `Collation' and `Charset' columns indicate the names of the collation and the character set with which it is associated. `Id' is the collation ID. `Default' indicates whether the collation is the default for its character set. `Compiled' indicates whether the character set is compiled into the server. `Sortlen' is related to the amount of memory required to sort strings expressed in the character set. To see the default collation for each character set, use the following statement. `Default' is a reserved word, so to use it as an identifier, it must be quoted as such: mysql> SHOW COLLATION WHERE `Default` = 'Yes'; +---------------------+----------+----+---------+----------+---------+ | Collation | Charset | Id | Default | Compiled | Sortlen | +---------------------+----------+----+---------+----------+---------+ | big5_chinese_ci | big5 | 1 | Yes | Yes | 1 | | dec8_swedish_ci | dec8 | 3 | Yes | Yes | 1 | | cp850_general_ci | cp850 | 4 | Yes | Yes | 1 | | hp8_english_ci | hp8 | 6 | Yes | Yes | 1 | | koi8r_general_ci | koi8r | 7 | Yes | Yes | 1 | | latin1_swedish_ci | latin1 | 8 | Yes | Yes | 1 | ...  File: manual.info, Node: show-columns, Next: show-contributors, Prev: show-collation, Up: show 13.4.5.6 `SHOW COLUMNS' Syntax .............................. SHOW [FULL] COLUMNS {FROM | IN} TBL_NAME [{FROM | IN} DB_NAME] [LIKE 'PATTERN' | WHERE EXPR] *Note `SHOW COLUMNS': show-columns. displays information about the columns in a given table. It also works for views. The `LIKE' clause, if present, indicates which column names to match. The `WHERE' clause can be given to select rows using more general conditions, as discussed in *Note extended-show::. mysql> SHOW COLUMNS FROM City; +------------+----------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +------------+----------+------+-----+---------+----------------+ | Id | int(11) | NO | PRI | NULL | auto_increment | | Name | char(35) | NO | | | | | Country | char(3) | NO | UNI | | | | District | char(20) | YES | MUL | | | | Population | int(11) | NO | | 0 | | +------------+----------+------+-----+---------+----------------+ 5 rows in set (0.00 sec) If the data types differ from what you expect them to be based on a *Note `CREATE TABLE': create-table. statement, note that MySQL sometimes changes data types when you create or alter a table. The conditions under which this occurs are described in *Note silent-column-changes::. The `FULL' keyword causes the output to include the column collation and comments, as well as the privileges you have for each column. You can use DB_NAME.TBL_NAME as an alternative to the `TBL_NAME FROM DB_NAME' syntax. In other words, these two statements are equivalent: mysql> SHOW COLUMNS FROM mytable FROM mydb; mysql> SHOW COLUMNS FROM mydb.mytable; *Note `SHOW COLUMNS': show-columns. displays the following values for each table column: `Field' indicates the column name. `Type' indicates the column data type. `Collation' indicates the collation for nonbinary string columns, or `NULL' for other columns. This value is displayed only if you use the `FULL' keyword. The `Null' field contains `YES' if `NULL' values can be stored in the column, `NO' if not. The `Key' field indicates whether the column is indexed: * If `Key' is empty, the column either is not indexed or is indexed only as a secondary column in a multiple-column, nonunique index. * If `Key' is `PRI', the column is a `PRIMARY KEY' or is one of the columns in a multiple-column `PRIMARY KEY'. * If `Key' is `UNI', the column is the first column of a `UNIQUE' index. (A `UNIQUE' index permits multiple `NULL' values, but you can tell whether the column permits `NULL' by checking the `Null' field.) * If `Key' is `MUL', the column is the first column of a nonunique index in which multiple occurrences of a given value are permitted within the column. If more than one of the `Key' values applies to a given column of a table, `Key' displays the one with the highest priority, in the order `PRI', `UNI', `MUL'. A `UNIQUE' index may be displayed as `PRI' if it cannot contain `NULL' values and there is no `PRIMARY KEY' in the table. A `UNIQUE' index may display as `MUL' if several columns form a composite `UNIQUE' index; although the combination of the columns is unique, each column can still hold multiple occurrences of a given value. The `Default' field indicates the default value that is assigned to the column. The `Extra' field contains any additional information that is available about a given column. The value is nonempty in these cases: `auto_increment' for columns that have the `AUTO_INCREMENT' attribute; as of MySQL 5.1.23, `on update CURRENT_TIMESTAMP' for *Note `TIMESTAMP': datetime. columns that have the `ON UPDATE CURRENT_TIMESTAMP' attribute. `Privileges' indicates the privileges you have for the column. This value is displayed only if you use the `FULL' keyword. `Comment' indicates any comment the column has. This value is displayed only if you use the `FULL' keyword. `SHOW FIELDS' is a synonym for *Note `SHOW COLUMNS': show-columns. You can also list a table's columns with the *Note `mysqlshow DB_NAME TBL_NAME': mysqlshow. command. The *Note `DESCRIBE': describe. statement provides information similar to *Note `SHOW COLUMNS': show-columns. See *Note describe::. The *Note `SHOW CREATE TABLE': show-create-table, *Note `SHOW TABLE STATUS': show-table-status, and *Note `SHOW INDEX': show-index. statements also provide information about tables. See *Note show::.  File: manual.info, Node: show-contributors, Next: show-create-database, Prev: show-columns, Up: show 13.4.5.7 `SHOW CONTRIBUTORS' Syntax ................................... SHOW CONTRIBUTORS The *Note `SHOW CONTRIBUTORS': show-contributors. statement displays information about the people who contribute to MySQL source or to causes that we support. For each contributor, it displays `Name', `Location', and `Comment' values. This statement was added in MySQL 5.1.12.  File: manual.info, Node: show-create-database, Next: show-create-event, Prev: show-contributors, Up: show 13.4.5.8 `SHOW CREATE DATABASE' Syntax ...................................... SHOW CREATE {DATABASE | SCHEMA} DB_NAME Shows the *Note `CREATE DATABASE': create-database. statement that creates the given database. *Note `SHOW CREATE SCHEMA': show-create-database. is a synonym for *Note `SHOW CREATE DATABASE': show-create-database. mysql> SHOW CREATE DATABASE test\G *************************** 1. row *************************** Database: test Create Database: CREATE DATABASE `test` /*!40100 DEFAULT CHARACTER SET latin1 */ mysql> SHOW CREATE SCHEMA test\G *************************** 1. row *************************** Database: test Create Database: CREATE DATABASE `test` /*!40100 DEFAULT CHARACTER SET latin1 */ *Note `SHOW CREATE DATABASE': show-create-database. quotes table and column names according to the value of the `sql_quote_show_create' option. See *Note server-system-variables::.  File: manual.info, Node: show-create-event, Next: show-create-function, Prev: show-create-database, Up: show 13.4.5.9 `SHOW CREATE EVENT' Syntax ................................... SHOW CREATE EVENT EVENT_NAME This statement displays the *Note `CREATE EVENT': create-event. statement needed to re-create a given event. For example (using the same event `e_daily' defined and then altered in *Note show-events::): mysql> SHOW CREATE EVENT test.e_daily\G *************************** 1. row *************************** Event: e_daily sql_mode: time_zone: SYSTEM Create Event: CREATE EVENT `e_daily` ON SCHEDULE EVERY 1 DAY STARTS CURRENT_TIMESTAMP + INTERVAL 6 HOUR ON COMPLETION NOT PRESERVE ENABLE COMMENT 'Saves total number of sessions then clears the table each day' DO BEGIN INSERT INTO site_activity.totals (time, total) SELECT CURRENT_TIMESTAMP, COUNT(*) FROM site_activity.sessions; DELETE FROM site_activity.sessions; END character_set_client: latin1 collation_connection: latin1_swedish_ci Database Collation: latin1_swedish_ci `character_set_client' is the session value of the `character_set_client' system variable when the event was created. `collation_connection' is the session value of the `collation_connection' system variable when the event was created. `Database Collation' is the collation of the database with which the event is associated. These columns were added in MySQL 5.1.21. Note that the output reflects the current status of the event (`ENABLE') rather than the status with which it was created. This statement was implemented in MySQL 5.1.6.  File: manual.info, Node: show-create-function, Next: show-create-procedure, Prev: show-create-event, Up: show 13.4.5.10 `SHOW CREATE FUNCTION' Syntax ....................................... SHOW CREATE FUNCTION FUNC_NAME This statement is similar to *Note `SHOW CREATE PROCEDURE': show-create-procedure. but for stored functions. See *Note show-create-procedure::.  File: manual.info, Node: show-create-procedure, Next: show-create-table, Prev: show-create-function, Up: show 13.4.5.11 `SHOW CREATE PROCEDURE' Syntax ........................................ SHOW CREATE PROCEDURE PROC_NAME This statement is a MySQL extension. It returns the exact string that can be used to re-create the named stored procedure. A similar statement, *Note `SHOW CREATE FUNCTION': show-create-function, displays information about stored functions (see *Note show-create-function::). Both statements require that you be the owner of the routine or have *Note `SELECT': select. access to the `mysql.proc' table. If you do not have privileges for the routine itself, the value displayed for the `Create Procedure' or `Create Function' field will be `NULL'. mysql> SHOW CREATE PROCEDURE test.simpleproc\G *************************** 1. row *************************** Procedure: simpleproc sql_mode: Create Procedure: CREATE PROCEDURE `simpleproc`(OUT param1 INT) BEGIN SELECT COUNT(*) INTO param1 FROM t; END character_set_client: latin1 collation_connection: latin1_swedish_ci Database Collation: latin1_swedish_ci mysql> SHOW CREATE FUNCTION test.hello\G *************************** 1. row *************************** Function: hello sql_mode: Create Function: CREATE FUNCTION `hello`(s CHAR(20)) RETURNS CHAR(50) RETURN CONCAT('Hello, ',s,'!') character_set_client: latin1 collation_connection: latin1_swedish_ci Database Collation: latin1_swedish_ci `character_set_client' is the session value of the `character_set_client' system variable when the routine was created. `collation_connection' is the session value of the `collation_connection' system variable when the routine was created. `Database Collation' is the collation of the database with which the routine is associated. These columns were added in MySQL 5.1.21.  File: manual.info, Node: show-create-table, Next: show-create-trigger, Prev: show-create-procedure, Up: show 13.4.5.12 `SHOW CREATE TABLE' Syntax .................................... SHOW CREATE TABLE TBL_NAME Shows the *Note `CREATE TABLE': create-table. statement that creates the given table. The statement requires the `SELECT' privilege for the table. This statement also works with views. mysql> SHOW CREATE TABLE t\G *************************** 1. row *************************** Table: t Create Table: CREATE TABLE t ( id INT(11) default NULL auto_increment, s char(60) default NULL, PRIMARY KEY (id) ) ENGINE=MyISAM *Note `SHOW CREATE TABLE': show-create-table. quotes table and column names according to the value of the `sql_quote_show_create' option. See *Note server-system-variables::.  File: manual.info, Node: show-create-trigger, Next: show-create-view, Prev: show-create-table, Up: show 13.4.5.13 `SHOW CREATE TRIGGER' Syntax ...................................... SHOW CREATE TRIGGER TRIGGER_NAME This statement shows a *Note `CREATE TRIGGER': create-trigger. statement that creates the given trigger. mysql> SHOW CREATE TRIGGER ins_sum\G *************************** 1. row *************************** Trigger: ins_sum sql_mode: SQL Original Statement: CREATE DEFINER=`bob`@`localhost` TRIGGER ins_sum BEFORE INSERT ON account FOR EACH ROW SET @sum = @sum + NEW.amount character_set_client: latin1 collation_connection: latin1_swedish_ci Database Collation: latin1_swedish_ci This statement was added in MySQL 5.1.21. You can also obtain information about trigger objects from `INFORMATION_SCHEMA', which contains a *Note `TRIGGERS': triggers-table. table. See *Note triggers-table::.  File: manual.info, Node: show-create-view, Next: show-databases, Prev: show-create-trigger, Up: show 13.4.5.14 `SHOW CREATE VIEW' Syntax ................................... SHOW CREATE VIEW VIEW_NAME This statement shows a *Note `CREATE VIEW': create-view. statement that creates the given view. mysql> SHOW CREATE VIEW v\G *************************** 1. row *************************** View: v Create View: CREATE ALGORITHM=UNDEFINED DEFINER=`bob`@`localhost` SQL SECURITY DEFINER VIEW `v` AS select 1 AS `a`,2 AS `b` character_set_client: latin1 collation_connection: latin1_swedish_ci `character_set_client' is the session value of the `character_set_client' system variable when the view was created. `collation_connection' is the session value of the `collation_connection' system variable when the view was created. These columns were added in MySQL 5.1.21. Use of *Note `SHOW CREATE VIEW': show-create-view. requires the `SHOW VIEW' privilege and the `SELECT' privilege for the view in question. You can also obtain information about view objects from `INFORMATION_SCHEMA', which contains a *Note `VIEWS': views-table. table. See *Note views-table::. MySQL lets you use different `sql_mode' settings to tell the server the type of SQL syntax to support. For example, you might use the `ANSI' SQL mode to ensure MySQL correctly interprets the standard SQL concatenation operator, the double bar (`||'), in your queries. If you then create a view that concatenates items, you might worry that changing the `sql_mode' setting to a value different from `ANSI' could cause the view to become invalid. But this is not the case. No matter how you write out a view definition, MySQL always stores it the same way, in a canonical form. Here is an example that shows how the server changes a double bar concatenation operator to a `CONCAT()' function: mysql> SET sql_mode = 'ANSI'; Query OK, 0 rows affected (0.00 sec) mysql> CREATE VIEW test.v AS SELECT 'a' || 'b' as col1; Query OK, 0 rows affected (0.01 sec) mysql> SHOW CREATE VIEW test.v\G *************************** 1. row *************************** View: v Create View: CREATE VIEW "v" AS select concat('a','b') AS "col1" ... 1 row in set (0.00 sec) The advantage of storing a view definition in canonical form is that changes made later to the value of `sql_mode' will not affect the results from the view. However an additional consequence is that comments prior to *Note `SELECT': select. are stripped from the definition by the server.  File: manual.info, Node: show-databases, Next: show-engine, Prev: show-create-view, Up: show 13.4.5.15 `SHOW DATABASES' Syntax ................................. SHOW {DATABASES | SCHEMAS} [LIKE 'PATTERN' | WHERE EXPR] *Note `SHOW DATABASES': show-databases. lists the databases on the MySQL server host. *Note `SHOW SCHEMAS': show-databases. is a synonym for *Note `SHOW DATABASES': show-databases. The `LIKE' clause, if present, indicates which database names to match. The `WHERE' clause can be given to select rows using more general conditions, as discussed in *Note extended-show::. You see only those databases for which you have some kind of privilege, unless you have the global *Note `SHOW DATABASES': show-databases. privilege. You can also get this list using the *Note `mysqlshow': mysqlshow. command. If the server was started with the `--skip-show-database' option, you cannot use this statement at all unless you have the `SHOW DATABASES' privilege. MySQL implements databases as directories in the data directory, so this statement simply lists directories in that location. However, the output may include names of directories that do not correspond to actual databases.  File: manual.info, Node: show-engine, Next: show-engines, Prev: show-databases, Up: show 13.4.5.16 `SHOW ENGINE' Syntax .............................. SHOW ENGINE ENGINE_NAME {STATUS | MUTEX} *Note `SHOW ENGINE': show-engine. displays operational information about a storage engine. The following statements currently are supported: SHOW ENGINE INNODB STATUS SHOW ENGINE INNODB MUTEX SHOW ENGINE {NDB | NDBCLUSTER} STATUS Older (and now deprecated) synonyms are *Note `SHOW INNODB STATUS': show-innodb-status. for *Note `SHOW ENGINE INNODB STATUS': show-engine. and `SHOW MUTEX STATUS' for *Note `SHOW ENGINE INNODB MUTEX': show-engine. *Note `SHOW INNODB STATUS': show-innodb-status. and `SHOW MUTEX STATUS' are removed in MySQL 5.5. In MySQL 5.0, *Note `SHOW ENGINE INNODB MUTEX': show-engine. is invoked as `SHOW MUTEX STATUS'. The latter statement displays similar information but in a somewhat different output format. *Note `SHOW ENGINE BDB LOGS': show-engine. formerly displayed status information about `BDB' log files. As of MySQL 5.1.12, the `BDB' storage engine is not supported, and this statement produces a warning. *Note `SHOW ENGINE INNODB STATUS': show-engine. displays extensive information from the standard `InnoDB' Monitor about the state of the `InnoDB' storage engine. For information about the standard monitor and other `InnoDB' Monitors that provide information about `InnoDB' processing, see *Note innodb-monitors::. *Note `SHOW ENGINE INNODB MUTEX': show-engine. displays `InnoDB' mutex statistics. From MySQL 5.1.2 to 5.1.14, the statement displays the following output fields: * `Type' Always `InnoDB'. * `Name' The mutex name and the source file where it is implemented. Example: `&pool->mutex:mem0pool.c' The mutex name indicates its purpose. For example, the `log_sys' mutex is used by the `InnoDB' logging subsystem and indicates how intensive logging activity is. The `buf_pool' mutex protects the `InnoDB' buffer pool. * `Status' The mutex status. The fields contains several values: * `count' indicates how many times the mutex was requested. * `spin_waits' indicates how many times the spinlock had to run. * `spin_rounds' indicates the number of spinlock rounds. (`spin_rounds' divided by `spin_waits' provides the average round count.) * `os_waits' indicates the number of operating system waits. This occurs when the spinlock did not work (the mutex was not locked during the spinlock and it was necessary to yield to the operating system and wait). * `os_yields' indicates the number of times a the thread trying to lock a mutex gave up its timeslice and yielded to the operating system (on the presumption that permitting other threads to run will free the mutex so that it can be locked). * `os_wait_times' indicates the amount of time (in ms) spent in operating system waits, if the `timed_mutexes' system variable is 1 (`ON'). If `timed_mutexes' is 0 (`OFF'), timing is disabled, so `os_wait_times' is 0. `timed_mutexes' is off by default. From MySQL 5.1.15 on, the statement displays the following output fields: * `Type' Always `InnoDB'. * `Name' The source file where the mutex is implemented, and the line number in the file where the mutex is created. The line number may change depending on your version of MySQL. * `Status' This field displays the same values as previously described (`count', `spin_waits', `spin_rounds', `os_waits', `os_yields', `os_wait_times'), but only if `UNIV_DEBUG' was defined at MySQL compilation time (for example, in `include/univ.h' in the `InnoDB' part of the MySQL source tree). If `UNIV_DEBUG' was not defined, the statement displays only the `os_waits' value. In the latter case (without `UNIV_DEBUG'), the information on which the output is based is insufficient to distinguish regular mutexes and mutexes that protect rw-locks (which permit multiple readers or a single writer). Consequently, the output may appear to contain multiple rows for the same mutex. Information from this statement can be used to diagnose system problems. For example, large values of `spin_waits' and `spin_rounds' may indicate scalability problems. If the server has the *Note `NDBCLUSTER': mysql-cluster. storage engine enabled, *Note `SHOW ENGINE NDB STATUS': show-engine. displays cluster status information such as the number of connected data nodes, the cluster connectstring, and cluster binlog epochs, as well as counts of various Cluster API objects created by the MySQL Server when connected to the cluster. Sample output from this statement is shown here: mysql> SHOW ENGINE NDB STATUS; +------------+-----------------------+--------------------------------------------------+ | Type | Name | Status | +------------+-----------------------+--------------------------------------------------+ | ndbcluster | connection | cluster_node_id=7, connected_host=192.168.0.103, connected_port=1186, number_of_data_nodes=4, number_of_ready_data_nodes=3, connect_count=0 | | ndbcluster | NdbTransaction | created=6, free=0, sizeof=212 | | ndbcluster | NdbOperation | created=8, free=8, sizeof=660 | | ndbcluster | NdbIndexScanOperation | created=1, free=1, sizeof=744 | | ndbcluster | NdbIndexOperation | created=0, free=0, sizeof=664 | | ndbcluster | NdbRecAttr | created=1285, free=1285, sizeof=60 | | ndbcluster | NdbApiSignal | created=16, free=16, sizeof=136 | | ndbcluster | NdbLabel | created=0, free=0, sizeof=196 | | ndbcluster | NdbBranch | created=0, free=0, sizeof=24 | | ndbcluster | NdbSubroutine | created=0, free=0, sizeof=68 | | ndbcluster | NdbCall | created=0, free=0, sizeof=16 | | ndbcluster | NdbBlob | created=1, free=1, sizeof=264 | | ndbcluster | NdbReceiver | created=4, free=0, sizeof=68 | | ndbcluster | binlog | latest_epoch=155467, latest_trans_epoch=148126, latest_received_binlog_epoch=0, latest_handled_binlog_epoch=0, latest_applied_binlog_epoch=0 | +------------+-----------------------+--------------------------------------------------+ The rows with `connection' and `binlog' in the `Name' column were added to the output of this statement in MySQL 5.1. The `Status' column in each of these rows provides information about the MySQL server's connection to the cluster and about the cluster binary log's status, respectively. The `Status' information is in the form of comma-delimited set of name/value pairs. The `connection' row's `Status' column contains the name/value pairs described in the following table. Name Value `cluster_node_id' The node ID of the MySQL server in the cluster `connected_host' The host name or IP address of the cluster management server to which the MySQL server is connected `connected_port' The port used by the MySQL server to connect to the management server (`connected_host') `number_of_data_nodes' The number of data nodes configured for the cluster (that is, the number of `[ndbd]' sections in the cluster `config.ini' file) `number_of_ready_data_nodes' The number of data nodes in the cluster that are actually running `connect_count' The number of times this *Note `mysqld': mysqld. has connected or reconnected to cluster data nodes The `binlog' row's `Status' column contains information relating to MySQL Cluster Replication. The name/value pairs it contains are described in the following table. Name Value `latest_epoch' The most recent epoch most recently run on this MySQL server (that is, the sequence number of the most recent transaction run on the server) `latest_trans_epoch' The most recent epoch processed by the cluster's data nodes `latest_received_binlog_epoch'The most recent epoch received by the binlog thread `latest_handled_binlog_epoch' The most recent epoch processed by the binlog thread (for writing to the binlog) `latest_applied_binlog_epoch' The most recent epoch actually written to the binlog See *Note mysql-cluster-replication::, for more information. The remaining rows from the output of *Note `SHOW ENGINE NDB STATUS': show-engine. which are most likely to prove useful in monitoring the cluster are listed here by `Name': * `NdbTransaction': The number and size of `NdbTransaction' objects that have been created. An `NdbTransaction' is created each time a table schema operation (such as *Note `CREATE TABLE': create-table. or *Note `ALTER TABLE': alter-table.) is performed on an *Note `NDB': mysql-cluster. table. * `NdbOperation': The number and size of `NdbOperation' objects that have been created. * `NdbIndexScanOperation': The number and size of `NdbIndexScanOperation' objects that have been created. * `NdbIndexOperation': The number and size of `NdbIndexOperation' objects that have been created. * `NdbRecAttr': The number and size of `NdbRecAttr' objects that have been created. In general, one of these is created each time a data manipulation statement is performed by an SQL node. * `NdbBlob': The number and size of `NdbBlob' objects that have been created. An `NdbBlob' is created for each new operation involving a *Note `BLOB': blob. column in an *Note `NDB': mysql-cluster. table. * `NdbReceiver': The number and size of any `NdbReceiver' object that have been created. The number in the `created' column is the same as the number of data nodes in the cluster to which the MySQL server has connected. *Note*: *Note `SHOW ENGINE NDB STATUS': show-engine. returns an empty result if no operations involving *Note `NDB': mysql-cluster. tables have been performed during the current session by the MySQL client accessing the SQL node on which this statement is run.  File: manual.info, Node: show-engines, Next: show-errors, Prev: show-engine, Up: show 13.4.5.17 `SHOW ENGINES' Syntax ............................... SHOW [STORAGE] ENGINES *Note `SHOW ENGINES': show-engines. displays status information about the server's storage engines. This is particularly useful for checking whether a storage engine is supported, or to see what the default engine is. `SHOW TABLE TYPES' is a synonym, but is deprecated and is removed in MySQL 5.5. mysql> SHOW ENGINES\G *************************** 1. row *************************** Engine: MEMORY Support: YES Comment: Hash based, stored in memory, useful for temporary tables Transactions: NO XA: NO Savepoints: NO *************************** 2. row *************************** Engine: MyISAM Support: DEFAULT Comment: Default engine as of MySQL 3.23 with great performance Transactions: NO XA: NO Savepoints: NO *************************** 3. row *************************** Engine: InnoDB Support: YES Comment: Supports transactions, row-level locking, and foreign keys Transactions: YES XA: YES Savepoints: YES *************************** 4. row *************************** Engine: EXAMPLE Support: YES Comment: Example storage engine Transactions: NO XA: NO Savepoints: NO *************************** 5. row *************************** Engine: ARCHIVE Support: YES Comment: Archive storage engine Transactions: NO XA: NO Savepoints: NO *************************** 6. row *************************** Engine: CSV Support: YES Comment: CSV storage engine Transactions: NO XA: NO Savepoints: NO *************************** 7. row *************************** Engine: BLACKHOLE Support: YES Comment: /dev/null storage engine (anything you write » to it disappears) Transactions: NO XA: NO Savepoints: NO *************************** 8. row *************************** Engine: FEDERATED Support: YES Comment: Federated MySQL storage engine Transactions: NO XA: NO Savepoints: NO *************************** 9. row *************************** Engine: MRG_MYISAM Support: YES Comment: Collection of identical MyISAM tables Transactions: NO XA: NO Savepoints: NO The output from *Note `SHOW ENGINES': show-engines. may vary according to the MySQL version used and other factors. The values shown in the `Support' column indicate the server's level of support for the storage engine, as shown in the following table. Value Meaning `YES' The engine is supported and is active `DEFAULT' Like `YES', plus this is the default engine `NO' The engine is not supported `DISABLED' The engine is supported but has been disabled A value of `NO' means that the server was compiled without support for the engine, so it cannot be enabled at runtime. A value of `DISABLED' occurs either because the server was started with an option that disables the engine, or because not all options required to enable it were given. In the latter case, the error log file should contain a reason indicating why the option is disabled. See *Note error-log::. You might also see `DISABLED' for a storage engine if the server was compiled to support it, but was started with a `--skip-ENGINE_NAME' option. For the *Note `NDBCLUSTER': mysql-cluster. storage engine, `DISABLED' means the server was compiled with support for MySQL Cluster, but was not started with the `--ndbcluster' option. All MySQL servers support `MyISAM' tables, because `MyISAM' is the default storage engine. It is not possible to disable `MyISAM'. The `Transactions', `XA', and `Savepoints' columns were added in MySQL 5.1.2. They indicate whether the storage engine supports transactions, XA transactions, and savepoints, respectively.  File: manual.info, Node: show-errors, Next: show-events, Prev: show-engines, Up: show 13.4.5.18 `SHOW ERRORS' Syntax .............................. SHOW ERRORS [LIMIT [OFFSET,] ROW_COUNT] SHOW COUNT(*) ERRORS This statement is similar to *Note `SHOW WARNINGS': show-warnings, except that instead of displaying errors, warnings, and notes, it displays only errors. The `LIMIT' clause has the same syntax as for the *Note `SELECT': select. statement. See *Note select::. The `SHOW COUNT(*) ERRORS' statement displays the number of errors. You can also retrieve this number from the `error_count' variable: SHOW COUNT(*) ERRORS; SELECT @@error_count; For more information, see *Note show-warnings::.  File: manual.info, Node: show-events, Next: show-function-code, Prev: show-errors, Up: show 13.4.5.19 `SHOW EVENTS' Syntax .............................. SHOW EVENTS [{FROM | IN} SCHEMA_NAME] [LIKE 'PATTERN' | WHERE EXPR] In its simplest form, *Note `SHOW EVENTS': show-events. lists all of the events in the current schema: mysql> SELECT CURRENT_USER(), SCHEMA(); +----------------+----------+ | CURRENT_USER() | SCHEMA() | +----------------+----------+ | jon@ghidora | myschema | +----------------+----------+ 1 row in set (0.00 sec) mysql> SHOW EVENTS\G *************************** 1. row *************************** Db: myschema Name: e_daily Definer: jon@ghidora Time zone: SYSTEM Type: RECURRING Execute at: NULL Interval value: 10 Interval field: SECOND Starts: 2006-02-09 10:41:23 Ends: NULL Status: ENABLED Originator: 0 character_set_client: latin1 collation_connection: latin1_swedish_ci Database Collation: latin1_swedish_ci To see events for a specific schema, use the `FROM' clause. For example, to see events for the `test' schema, use the following statement: SHOW EVENTS FROM test; The `LIKE' clause, if present, indicates which event names to match. The `WHERE' clause can be given to select rows using more general conditions, as discussed in *Note extended-show::. *Note `SHOW EVENTS': show-events. output has the following columns: * `Db': The schema (database) on which the event is defined. * `Name': The name of the event. * `Time zone': The event time zone, which is the time zone used for scheduling the event and that is in effect within the event as it executes. The default value is `SYSTEM'. This column was added in MySQL 5.1.17. See *Note news-5-1-17::, for important information if you are using the Event Scheduler and are upgrading to MySQL 5.1.17 or later from an earlier version. * `Definer': The account of the user who created the event, in `'USER_NAME'@'HOST_NAME'' format. * `Type': The event repetition type, either `ONE TIME' (transient) or `RECURRING' (repeating). * `Execute At': The date and time when a transient event is set to execute. Shown as a *Note `DATETIME': datetime. value. For a recurring event, the value of this column is always `NULL'. * `Interval Value': For a recurring event, the number of intervals to wait between event executions. For a transient event, the value of this column is always `NULL'. * `Interval Field': The time units used for the interval which a recurring event waits before repeating. For a transient event, the value of this column is always `NULL'. * `Starts': The start date and time for a recurring event. This is displayed as a *Note `DATETIME': datetime. value, and is `NULL' if no start date and time are defined for the event. (Prior to MySQL 5.1.8, it defaulted to `'0000-00-00 00:00:00'' in such cases.) For a transient event, this column is always `NULL'. * `Ends': The end date and time for a recurring event. This is displayed as a *Note `DATETIME': datetime. value, and defaults to `NULL' if no end date and time is defined for the event. For a transient event, this column is always `NULL'. * `Status': The event status. One of `ENABLED', `DISABLED', or `SLAVESIDE_DISABLED'. `SLAVESIDE_DISABLED' was added in MySQL 5.1.18. This value indicates that the creation of the event occurred on another MySQL server acting as a replication master and replicated to the current MySQL server which is acting as a slave, but the event is not presently being executed on the slave. * `Originator': The server ID of the MySQL server on which the event was created. Defaults to 0. This column was added in MySQL 5.1.18. * `character_set_client' is the session value of the `character_set_client' system variable when the routine was created. `collation_connection' is the session value of the `collation_connection' system variable when the routine was created. `Database Collation' is the collation of the database with which the routine is associated. These columns were added in MySQL 5.1.21. For more information about `SLAVE_DISABLED' and the `Originator' column, see *Note replication-features-invoked::. The event action statement is not shown in the output of *Note `SHOW EVENTS': show-events. Use *Note `SHOW CREATE EVENT': show-create-event. or the *Note `INFORMATION_SCHEMA.EVENTS': events-table. table. Times displayed by *Note `SHOW EVENTS': show-events. are given in the event time zone (or UTC prior to MySQL 5.1.17), as discussed in *Note events-metadata::. The columns in the output of *Note `SHOW EVENTS': show-events. are similar to, but not identical to the columns in the *Note `INFORMATION_SCHEMA.EVENTS': events-table. table. See *Note events-table::. *Note `SHOW EVENTS': show-events. was added in MySQL 5.1.6. *Note*: In MySQL 5.1.11 and earlier, *Note `SHOW EVENTS': show-events. displayed only those events for which the current user was the definer, and the *Note `SHOW FULL EVENTS': show-events. statement was used for viewing events defined by all users on a given schema. *Note `SHOW FULL EVENTS': show-events. was removed in MySQL 5.1.12.  File: manual.info, Node: show-function-code, Next: show-function-status, Prev: show-events, Up: show 13.4.5.20 `SHOW FUNCTION CODE' Syntax ..................................... SHOW FUNCTION CODE FUNC_NAME This statement is similar to *Note `SHOW PROCEDURE CODE': show-procedure-code. but for stored functions. See *Note show-procedure-code::.  File: manual.info, Node: show-function-status, Next: show-grants, Prev: show-function-code, Up: show 13.4.5.21 `SHOW FUNCTION STATUS' Syntax ....................................... SHOW FUNCTION STATUS [LIKE 'PATTERN' | WHERE EXPR] This statement is similar to *Note `SHOW PROCEDURE STATUS': show-procedure-status. but for stored functions. See *Note show-procedure-status::.  File: manual.info, Node: show-grants, Next: show-index, Prev: show-function-status, Up: show 13.4.5.22 `SHOW GRANTS' Syntax .............................. SHOW GRANTS [FOR USER] This statement lists the *Note `GRANT': grant. statement or statements that must be issued to duplicate the privileges that are granted to a MySQL user account. The account is named using the same format as for the *Note `GRANT': grant. statement; for example, `'jeffrey'@'localhost''. If you specify only the user name part of the account name, a host name part of `'%'' is used. For additional information about specifying account names, see *Note grant::. mysql> SHOW GRANTS FOR 'root'@'localhost'; +---------------------------------------------------------------------+ | Grants for root@localhost | +---------------------------------------------------------------------+ | GRANT ALL PRIVILEGES ON *.* TO 'root'@'localhost' WITH GRANT OPTION | +---------------------------------------------------------------------+ To list the privileges granted to the account that you are using to connect to the server, you can use any of the following statements: SHOW GRANTS; SHOW GRANTS FOR CURRENT_USER; SHOW GRANTS FOR CURRENT_USER(); As of MySQL 5.1.12, if `SHOW GRANTS FOR CURRENT_USER' (or any of the equivalent syntaxes) is used in `DEFINER' context, such as within a stored procedure that is defined with `SQL SECURITY DEFINER'), the grants displayed are those of the definer and not the invoker. *Note `SHOW GRANTS': show-grants. displays only the privileges granted explicitly to the named account. Other privileges might be available to the account, but they are not displayed. For example, if an anonymous account exists, the named account might be able to use its privileges, but *Note `SHOW GRANTS': show-grants. will not display them. *Note `SHOW GRANTS': show-grants. requires the `SELECT' privilege for the `mysql' database.  File: manual.info, Node: show-index, Next: show-innodb-status, Prev: show-grants, Up: show 13.4.5.23 `SHOW INDEX' Syntax ............................. SHOW {INDEX | INDEXES | KEYS} {FROM | IN} TBL_NAME [{FROM | IN} DB_NAME] [WHERE EXPR] *Note `SHOW INDEX': show-index. returns table index information. The format resembles that of the `SQLStatistics' call in ODBC. *Note `SHOW INDEX': show-index. returns the following fields: * `Table' The name of the table. * `Non_unique' 0 if the index cannot contain duplicates, 1 if it can. * `Key_name' The name of the index. * `Seq_in_index' The column sequence number in the index, starting with 1. * `Column_name' The column name. * `Collation' How the column is sorted in the index. In MySQL, this can have values ``A'' (Ascending) or `NULL' (Not sorted). * `Cardinality' An estimate of the number of unique values in the index. This is updated by running *Note `ANALYZE TABLE': analyze-table. or *Note `myisamchk -a': myisamchk. `Cardinality' is counted based on statistics stored as integers, so the value is not necessarily exact even for small tables. The higher the cardinality, the greater the chance that MySQL uses the index when doing joins. * `Sub_part' The number of indexed characters if the column is only partly indexed, `NULL' if the entire column is indexed. * `Packed' Indicates how the key is packed. `NULL' if it is not. * `Null' Contains `YES' if the column may contain `NULL'. If not, the column contains `NO'. Contains `YES' if the column may contain `NULL' values and `''' if not. * `Index_type' The index method used (`BTREE', `FULLTEXT', `HASH', `RTREE'). * `Comment' Information about the index not described in its own column, such as `disabled' if the index is disabled. You can use DB_NAME.TBL_NAME as an alternative to the `TBL_NAME FROM DB_NAME' syntax. These two statements are equivalent: SHOW INDEX FROM mytable FROM mydb; SHOW INDEX FROM mydb.mytable; The `WHERE' clause can be given to select rows using more general conditions, as discussed in *Note extended-show::. You can also list a table's indexes with the *Note `mysqlshow -k DB_NAME TBL_NAME': mysqlshow. command.  File: manual.info, Node: show-innodb-status, Next: show-master-status, Prev: show-index, Up: show 13.4.5.24 `SHOW INNODB STATUS' Syntax ..................................... SHOW INNODB STATUS In MySQL 5.1, this is a deprecated synonym for *Note `SHOW ENGINE INNODB STATUS': show-engine. See *Note show-engine::. *Note `SHOW INNODB STATUS': show-innodb-status. is removed in MySQL 5.5.  File: manual.info, Node: show-master-status, Next: show-open-tables, Prev: show-innodb-status, Up: show 13.4.5.25 `SHOW MASTER STATUS' Syntax ..................................... SHOW MASTER STATUS This statement provides status information about the binary log files of the master. It requires either the `SUPER' or `REPLICATION CLIENT' privilege. Example: mysql> SHOW MASTER STATUS; +---------------+----------+--------------+------------------+ | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | +---------------+----------+--------------+------------------+ | mysql-bin.003 | 73 | test | manual,mysql | +---------------+----------+--------------+------------------+  File: manual.info, Node: show-open-tables, Next: show-plugins, Prev: show-master-status, Up: show 13.4.5.26 `SHOW OPEN TABLES' Syntax ................................... SHOW OPEN TABLES [{FROM | IN} DB_NAME] [LIKE 'PATTERN' | WHERE EXPR] *Note `SHOW OPEN TABLES': show-open-tables. lists the non-`TEMPORARY' tables that are currently open in the table cache. See *Note table-cache::. The `WHERE' clause can be given to select rows using more general conditions, as discussed in *Note extended-show::. The `FROM' and `LIKE' clauses may be used beginning with MySQL 5.1.24. The `LIKE' clause, if present, indicates which table names to match. The `FROM' clause, if present, restricts the tables shown to those present in the DB_NAME database. *Note `SHOW OPEN TABLES': show-open-tables. returns the following columns: * `Database' The database containing the table. * `Table' The table name. * `In_use' The number of table locks or lock requests there are for the table. For example, if one client acquires a lock for a table using `LOCK TABLE t1 WRITE', `In_use' will be 1. If another client issues `LOCK TABLE t1 WRITE' while the table remains locked, the client will block waiting for the lock, but the lock request causes `In_use' to be 2. If the count is zero, the table is open but not currently being used. `In_use' is also increased by the *Note `HANDLER ... OPEN': handler. statement and decreased by *Note `HANDLER ... CLOSE': handler. * `Name_locked' Whether the table name is locked. Name locking is used for operations such as dropping or renaming tables.  File: manual.info, Node: show-plugins, Next: show-privileges, Prev: show-open-tables, Up: show 13.4.5.27 `SHOW PLUGINS' Syntax ............................... SHOW PLUGINS *Note `SHOW PLUGINS': show-plugins. displays information about server plugins. Plugin information is also available in the `INFORMATION_SCHEMA.PLUGINS' table. See *Note plugins-table::. Example of *Note `SHOW PLUGINS': show-plugins. output: mysql> SHOW PLUGINS\G *************************** 1. row *************************** Name: binlog Status: ACTIVE Type: STORAGE ENGINE Library: NULL License: GPL *************************** 2. row *************************** Name: CSV Status: ACTIVE Type: STORAGE ENGINE Library: NULL License: GPL *************************** 3. row *************************** Name: MEMORY Status: ACTIVE Type: STORAGE ENGINE Library: NULL License: GPL *************************** 4. row *************************** Name: MyISAM Status: ACTIVE Type: STORAGE ENGINE Library: NULL License: GPL ... *Note `SHOW PLUGINS': show-plugins. returns the following columns: * `Name': The name used to refer to the plugin in statements such as *Note `INSTALL PLUGIN': install-plugin. and *Note `UNINSTALL PLUGIN': uninstall-plugin. * `Status': The plugin status, one of `ACTIVE', `INACTIVE', `DISABLED', or `DELETED'. * `Type': The type of plugin, such as `STORAGE ENGINE' or `INFORMATION_SCHEMA'. * `Library': The name of the plugin shared object file. This is the name used to refer to the plugin file in statements such as *Note `INSTALL PLUGIN': install-plugin. and *Note `UNINSTALL PLUGIN': uninstall-plugin. This file is located in the directory named by the `plugin_dir' system variable. If the library name is `NULL', the plugin is compiled in and cannot be uninstalled with *Note `UNINSTALL PLUGIN': uninstall-plugin. * `License': How the plugin is licensed; for example, `GPL'. For plugins installed with *Note `INSTALL PLUGIN': install-plugin, the `Name' and `Library' values are also registered in the `mysql.plugin' table. For information about plugin data structures that form the basis of the information displayed by *Note `SHOW PLUGINS': show-plugins, see *Note plugin-api::. `SHOW PLUGIN' was added in MySQL 5.1.5 and renamed to *Note `SHOW PLUGINS': show-plugins. in 5.1.9. `SHOW PLUGIN' is deprecated as of 5.1.9 and generates a warning, and is removed in MySQL 5.5.)  File: manual.info, Node: show-privileges, Next: show-procedure-code, Prev: show-plugins, Up: show 13.4.5.28 `SHOW PRIVILEGES' Syntax .................................. SHOW PRIVILEGES *Note `SHOW PRIVILEGES': show-privileges. shows the list of system privileges that the MySQL server supports. The exact list of privileges depends on the version of your server. mysql> SHOW PRIVILEGES\G *************************** 1. row *************************** Privilege: Alter Context: Tables Comment: To alter the table *************************** 2. row *************************** Privilege: Alter routine Context: Functions,Procedures Comment: To alter or drop stored functions/procedures *************************** 3. row *************************** Privilege: Create Context: Databases,Tables,Indexes Comment: To create new databases and tables *************************** 4. row *************************** Privilege: Create routine Context: Functions,Procedures Comment: To use CREATE FUNCTION/PROCEDURE *************************** 5. row *************************** Privilege: Create temporary tables Context: Databases Comment: To use CREATE TEMPORARY TABLE ... Privileges belonging to a specific user are displayed by the *Note `SHOW GRANTS': show-grants. statement. See *Note show-grants::, for more information.  File: manual.info, Node: show-procedure-code, Next: show-procedure-status, Prev: show-privileges, Up: show 13.4.5.29 `SHOW PROCEDURE CODE' Syntax ...................................... SHOW PROCEDURE CODE PROC_NAME This statement is a MySQL extension that is available only for servers that have been built with debugging support. It displays a representation of the internal implementation of the named stored procedure. A similar statement, *Note `SHOW FUNCTION CODE': show-function-code, displays information about stored functions (see *Note show-function-code::). Both statements require that you be the owner of the routine or have *Note `SELECT': select. access to the `mysql.proc' table. If the named routine is available, each statement produces a result set. Each row in the result set corresponds to one `instruction' in the routine. The first column is `Pos', which is an ordinal number beginning with 0. The second column is `Instruction', which contains an SQL statement (usually changed from the original source), or a directive which has meaning only to the stored-routine handler. mysql> DELIMITER // mysql> CREATE PROCEDURE p1 () -> BEGIN -> DECLARE fanta INT DEFAULT 55; -> DROP TABLE t2; -> LOOP -> INSERT INTO t3 VALUES (fanta); -> END LOOP; -> END// Query OK, 0 rows affected (0.00 sec) mysql> SHOW PROCEDURE CODE p1// +-----+----------------------------------------+ | Pos | Instruction | +-----+----------------------------------------+ | 0 | set fanta@0 55 | | 1 | stmt 9 "DROP TABLE t2" | | 2 | stmt 5 "INSERT INTO t3 VALUES (fanta)" | | 3 | jump 2 | +-----+----------------------------------------+ 4 rows in set (0.00 sec) In this example, the nonexecutable `BEGIN' and `END' statements have disappeared, and for the `DECLARE VARIABLE_NAME' statement, only the executable part appears (the part where the default is assigned). For each statement that is taken from source, there is a code word `stmt' followed by a type (9 means `DROP', 5 means *Note `INSERT': insert, and so on). The final row contains an instruction `jump 2', meaning `GOTO instruction #2'. These statements were added in MySQL 5.1.3.  File: manual.info, Node: show-procedure-status, Next: show-processlist, Prev: show-procedure-code, Up: show 13.4.5.30 `SHOW PROCEDURE STATUS' Syntax ........................................ SHOW PROCEDURE STATUS [LIKE 'PATTERN' | WHERE EXPR] This statement is a MySQL extension. It returns characteristics of a stored procedure, such as the database, name, type, creator, creation and modification dates, and character set information. A similar statement, *Note `SHOW FUNCTION STATUS': show-function-status, displays information about stored functions (see *Note show-function-status::). The `LIKE' clause, if present, indicates which procedure or function names to match. The `WHERE' clause can be given to select rows using more general conditions, as discussed in *Note extended-show::. mysql> SHOW PROCEDURE STATUS LIKE 'sp1'\G *************************** 1. row *************************** Db: test Name: sp1 Type: PROCEDURE Definer: testuser@localhost Modified: 2004-08-03 15:29:37 Created: 2004-08-03 15:29:37 Security_type: DEFINER Comment: character_set_client: latin1 collation_connection: latin1_swedish_ci Database Collation: latin1_swedish_ci `character_set_client' is the session value of the `character_set_client' system variable when the routine was created. `collation_connection' is the session value of the `collation_connection' system variable when the routine was created. `Database Collation' is the collation of the database with which the routine is associated. These columns were added in MySQL 5.1.21. You can also get information about stored routines from the *Note `ROUTINES': routines-table. table in `INFORMATION_SCHEMA'. See *Note routines-table::.  File: manual.info, Node: show-processlist, Next: show-profile, Prev: show-procedure-status, Up: show 13.4.5.31 `SHOW PROCESSLIST' Syntax ................................... SHOW [FULL] PROCESSLIST *Note `SHOW PROCESSLIST': show-processlist. shows you which threads are running. You can also get this information from the `INFORMATION_SCHEMA' *Note `PROCESSLIST': processlist-table. table or the *Note `mysqladmin processlist': mysqladmin. command. If you have the `PROCESS' privilege, you can see all threads. Otherwise, you can see only your own threads (that is, threads associated with the MySQL account that you are using). If you do not use the `FULL' keyword, only the first 100 characters of each statement are shown in the `Info' field. This statement is very useful if you get the `too many connections' error message and want to find out what is going on. MySQL reserves one extra connection to be used by accounts that have the `SUPER' privilege, to ensure that administrators should always be able to connect and check the system (assuming that you are not giving this privilege to all your users). Threads can be killed with the *Note `KILL': kill. statement. See *Note kill::. Here is an example of *Note `SHOW PROCESSLIST': show-processlist. output: mysql> SHOW FULL PROCESSLIST\G *************************** 1. row *************************** Id: 1 User: system user Host: db: NULL Command: Connect Time: 1030455 State: Waiting for master to send event Info: NULL *************************** 2. row *************************** Id: 2 User: system user Host: db: NULL Command: Connect Time: 1004 State: Has read all relay log; waiting for the slave I/O thread to update it Info: NULL *************************** 3. row *************************** Id: 3112 User: replikator Host: artemis:2204 db: NULL Command: Binlog Dump Time: 2144 State: Has sent all binlog to slave; waiting for binlog to be updated Info: NULL *************************** 4. row *************************** Id: 3113 User: replikator Host: iconnect2:45781 db: NULL Command: Binlog Dump Time: 2086 State: Has sent all binlog to slave; waiting for binlog to be updated Info: NULL *************************** 5. row *************************** Id: 3123 User: stefan Host: localhost db: apollon Command: Query Time: 0 State: NULL Info: SHOW FULL PROCESSLIST 5 rows in set (0.00 sec) The columns produced by *Note `SHOW PROCESSLIST': show-processlist. have the following meanings: * `Id' The connection identifier. * `User' The MySQL user who issued the statement. If this is `system user', it refers to a nonclient thread spawned by the server to handle tasks internally. This could be the I/O or SQL thread used on replication slaves or a delayed-row handler. `unauthenticated user' refers to a thread that has become associated with a client connection but for which authentication of the client user has not yet been done. `event_scheduler' refers to the thread that monitors scheduled events. For `system user', there is no host specified in the `Host' column. * `Host' The host name of the client issuing the statement (except for `system user' where there is no host). *Note `SHOW PROCESSLIST': show-processlist. reports the host name for TCP/IP connections in `HOST_NAME:CLIENT_PORT' format to make it easier to determine which client is doing what. * `db' The default database, if one is selected, otherwise `NULL'. * `Command' The type of command the thread is executing. For descriptions for thread commands, see *Note thread-information::. The value of this column corresponds to the `COM_XXX' commands of the client/server protocol and `Com_XXX' status variables. See *Note server-status-variables:: * `Time' The time in seconds that the thread has been in its current state. * `State' An action, event, or state that indicates what the thread is doing. Descriptions for `State' values can be found at *Note thread-information::. Most states correspond to very quick operations. If a thread stays in a given state for many seconds, there might be a problem that needs to be investigated. For the *Note `SHOW PROCESSLIST': show-processlist. statement, the value of `State' is `NULL'. * `Info' The statement the thread is executing, or `NULL' if it is not executing any statement. The statement might be the one sent to the server, or an innermost statement if the statement executes other statements. For example, if a `CALL' statement executes a stored procedure that is executing a *Note `SELECT': select. statement, the `Info' value shows the *Note `SELECT': select. statement.  File: manual.info, Node: show-profile, Next: show-profiles, Prev: show-processlist, Up: show 13.4.5.32 `SHOW PROFILE' Syntax ............................... SHOW PROFILES The *Note `SHOW PROFILE': show-profile. statement display profiling information that indicates resource usage for statements executed during the course of the current session. It is used together with *Note `SHOW PROFILES': show-profiles.; see *Note show-profiles::.  File: manual.info, Node: show-profiles, Next: show-scheduler-status, Prev: show-profile, Up: show 13.4.5.33 `SHOW PROFILES' Syntax ................................ SHOW PROFILE [TYPE [, TYPE] ... ] [FOR QUERY N] [LIMIT ROW_COUNT [OFFSET OFFSET]] TYPE: ALL | BLOCK IO | CONTEXT SWITCHES | CPU | IPC | MEMORY | PAGE FAULTS | SOURCE | SWAPS The *Note `SHOW PROFILES': show-profiles. and *Note `SHOW PROFILE': show-profile. statements display profiling information that indicates resource usage for statements executed during the course of the current session. Profiling is controlled by the `profiling' session variable, which has a default value of 0 (`OFF'). Profiling is enabled by setting `profiling' to 1 or `ON': mysql> SET profiling = 1; *Note `SHOW PROFILES': show-profiles. displays a list of the most recent statements sent to the master. The size of the list is controlled by the `profiling_history_size' session variable, which has a default value of 15. The maximum value is 100. Setting the value to 0 has the practical effect of disabling profiling. All statements are profiled except *Note `SHOW PROFILES': show-profiles. and *Note `SHOW PROFILE': show-profile, so you will find neither of those statements in the profile list. Malformed statements are profiled. For example, `SHOW PROFILING' is an illegal statement, and a syntax error occurs if you try to execute it, but it will show up in the profiling list. *Note `SHOW PROFILE': show-profile. displays detailed information about a single statement. Without the `FOR QUERY N' clause, the output pertains to the most recently executed statement. If `FOR QUERY N' is included, *Note `SHOW PROFILE': show-profile. displays information for statement N. The values of N correspond to the `Query_ID' values displayed by *Note `SHOW PROFILES': show-profiles. The `LIMIT ROW_COUNT' clause may be given to limit the output to ROW_COUNT rows. If `LIMIT' is given, `OFFSET OFFSET' may be added to begin the output OFFSET rows into the full set of rows. By default, *Note `SHOW PROFILE': show-profile. displays `Status' and `Duration' columns. The `Status' values are like the `State' values displayed by *Note `SHOW PROCESSLIST': show-processlist, although there might be some minor differences in interpretion for the two statements for some status values (see *Note thread-information::). Optional TYPE values may be specified to display specific additional types of information: * `ALL' displays all information * `BLOCK IO' displays counts for block input and output operations * `CONTEXT SWITCHES' displays counts for voluntary and involuntary context switches * `CPU' displays user and system CPU usage times * `IPC' displays counts for messages sent and received * `MEMORY' is not currently implemented * `PAGE FAULTS' displays counts for major and minor page faults * `SOURCE' displays the names of functions from the source code, together with the name and line number of the file in which the function occurs * `SWAPS' displays swap counts Profiling is enabled per session. When a session ends, its profiling information is lost. mysql> SELECT @@profiling; +-------------+ | @@profiling | +-------------+ | 0 | +-------------+ 1 row in set (0.00 sec) mysql> SET profiling = 1; Query OK, 0 rows affected (0.00 sec) mysql> DROP TABLE IF EXISTS t1; Query OK, 0 rows affected, 1 warning (0.00 sec) mysql> CREATE TABLE T1 (id INT); Query OK, 0 rows affected (0.01 sec) mysql> SHOW PROFILES; +----------+----------+--------------------------+ | Query_ID | Duration | Query | +----------+----------+--------------------------+ | 0 | 0.000088 | SET PROFILING = 1 | | 1 | 0.000136 | DROP TABLE IF EXISTS t1 | | 2 | 0.011947 | CREATE TABLE t1 (id INT) | +----------+----------+--------------------------+ 3 rows in set (0.00 sec) mysql> SHOW PROFILE; +----------------------+----------+ | Status | Duration | +----------------------+----------+ | checking permissions | 0.000040 | | creating table | 0.000056 | | After create | 0.011363 | | query end | 0.000375 | | freeing items | 0.000089 | | logging slow query | 0.000019 | | cleaning up | 0.000005 | +----------------------+----------+ 7 rows in set (0.00 sec) mysql> SHOW PROFILE FOR QUERY 1; +--------------------+----------+ | Status | Duration | +--------------------+----------+ | query end | 0.000107 | | freeing items | 0.000008 | | logging slow query | 0.000015 | | cleaning up | 0.000006 | +--------------------+----------+ 4 rows in set (0.00 sec) mysql> SHOW PROFILE CPU FOR QUERY 2; +----------------------+----------+----------+------------+ | Status | Duration | CPU_user | CPU_system | +----------------------+----------+----------+------------+ | checking permissions | 0.000040 | 0.000038 | 0.000002 | | creating table | 0.000056 | 0.000028 | 0.000028 | | After create | 0.011363 | 0.000217 | 0.001571 | | query end | 0.000375 | 0.000013 | 0.000028 | | freeing items | 0.000089 | 0.000010 | 0.000014 | | logging slow query | 0.000019 | 0.000009 | 0.000010 | | cleaning up | 0.000005 | 0.000003 | 0.000002 | +----------------------+----------+----------+------------+ 7 rows in set (0.00 sec) *Note*: Profiling is only partially functional on some architectures. For values that depend on the `getrusage()' system call, `NULL' is returned on systems such as Windows that do not support the call. In addition, profiling is per process and not per thread. This means that activity on threads within the server other than your own may affect the timing information that you see. *Note `SHOW PROFILES': show-profiles. and *Note `SHOW PROFILE': show-profile. were added in MySQL 5.1.24 (but were not added to binary distributions by default until 5.1.28). You can also get profiling information from the *Note `PROFILING': profiling-table. table in `INFORMATION_SCHEMA'. See *Note profiling-table::. For example, the following queries produce the same result: SHOW PROFILE FOR QUERY 2; SELECT STATE, FORMAT(DURATION, 6) AS DURATION FROM INFORMATION_SCHEMA.PROFILING WHERE QUERY_ID = 2 ORDER BY SEQ;  File: manual.info, Node: show-scheduler-status, Next: show-slave-hosts, Prev: show-profiles, Up: show 13.4.5.34 `SHOW SCHEDULER STATUS' Syntax ........................................ SHOW SCHEDULER STATUS This statement provides debugging information regarding the Event Scheduler's state. It is supported only in `-debug' builds of MySQL 5.1.11, and was removed in 5.1.12 and subsequent releases. Sample output is shown here: +--------------------------------+---------------------+ | Name | Value | +--------------------------------+---------------------+ | scheduler state | INITIALIZED | | thread_id | NULL | | scheduler last locked at | init_scheduler::313 | | scheduler last unlocked at | init_scheduler::318 | | scheduler waiting on condition | 0 | | scheduler workers count | 0 | | scheduler executed events | 0 | | scheduler data locked | 0 | | queue element count | 1 | | queue data locked | 0 | | queue data attempting lock | 0 | | queue last locked at | create_event::218 | | queue last unlocked at | create_event::222 | | queue last attempted lock at | ::0 | | queue waiting on condition | 0 | | next activation at | 0-00-00 00:00:00 | +--------------------------------+---------------------+ In MySQL 5.1.12 and later, this information can be obtained using *Note `mysqladmin debug': mysqladmin. (See *Note mysqladmin::.) For more information about obtaining Event Scheduler status information, see *Note events-status-info::.  File: manual.info, Node: show-slave-hosts, Next: show-slave-status, Prev: show-scheduler-status, Up: show 13.4.5.35 `SHOW SLAVE HOSTS' Syntax ................................... SHOW SLAVE HOSTS Displays a list of replication slaves currently registered with the master. Only slaves started with the `--report-host=HOST_NAME' option are visible in this list. The list is displayed on any server (not just the master server). The output looks like this: mysql> SHOW SLAVE HOSTS; +------------+-----------+------+-----------+ | Server_id | Host | Port | Master_id | +------------+-----------+------+-----------+ | 192168010 | iconnect2 | 3306 | 192168011 | | 1921680101 | athena | 3306 | 192168011 | +------------+-----------+------+-----------+ * `Server_id': The unique server ID of the slave server, as configured in the server's option file, or on the command line with `--server-id=VALUE'. * `Host': The host name of the slave server, as configured in the server's option file, or on the command line with `--report-host=HOST_NAME'. Note that this can differ from the machine name as configured in the operating system. * `Port': The port the slave server is listening on. * `Master_id': The unique server ID of the master server that the slave server is replicating from. Some MySQL versions report another variable, `Rpl_recovery_rank'. This variable was never used, and was eventually removed. (Bug#13963)  File: manual.info, Node: show-slave-status, Next: show-status, Prev: show-slave-hosts, Up: show 13.4.5.36 `SHOW SLAVE STATUS' Syntax .................................... SHOW SLAVE STATUS This statement provides status information on essential parameters of the slave threads. It requires either the `SUPER' or `REPLICATION CLIENT' privilege. If you issue this statement using the *Note `mysql': mysql. client, you can use a `\G' statement terminator rather than a semicolon to obtain a more readable vertical layout: mysql> SHOW SLAVE STATUS\G *************************** 1. row *************************** Slave_IO_State: Waiting for master to send event Master_Host: localhost Master_User: root Master_Port: 3306 Connect_Retry: 3 Master_Log_File: gbichot-bin.005 Read_Master_Log_Pos: 79 Relay_Log_File: gbichot-relay-bin.005 Relay_Log_Pos: 548 Relay_Master_Log_File: gbichot-bin.005 Slave_IO_Running: Yes Slave_SQL_Running: Yes Replicate_Do_DB: Replicate_Ignore_DB: Replicate_Do_Table: Replicate_Ignore_Table: Replicate_Wild_Do_Table: Replicate_Wild_Ignore_Table: Last_Errno: 0 Last_Error: Skip_Counter: 0 Exec_Master_Log_Pos: 79 Relay_Log_Space: 552 Until_Condition: None Until_Log_File: Until_Log_Pos: 0 Master_SSL_Allowed: No Master_SSL_CA_File: Master_SSL_CA_Path: Master_SSL_Cert: Master_SSL_Cipher: Master_SSL_Key: Seconds_Behind_Master: 8 Master_SSL_Verify_Server_Cert: No Last_IO_Errno: 0 Last_IO_Error: Last_SQL_Errno: 0 Last_SQL_Error: The following list describes the fields returned by *Note `SHOW SLAVE STATUS': show-slave-status. For additional information about interpreting their meanings, see *Note replication-administration-status::. * `Slave_IO_State' A copy of the `State' field of the *Note `SHOW PROCESSLIST': show-processlist. output for the slave I/O thread. This tells you what the thread is doing: trying to connect to the master, waiting for events from the master, reconnecting to the master, and so on. Possible states are listed in *Note replication-implementation-details::. * `Master_Host' The master host that the slave is connected to. * `Master_User' The user name of the account used to connect to the master. * `Master_Port' The port used to connect to the master. * `Connect_Retry' The number of seconds between connect retries (default 60). This can be set with the *Note `CHANGE MASTER TO': change-master-to. statement or `--master-connect-retry' option. * `Master_Log_File' The name of the master binary log file from which the I/O thread is currently reading. * `Read_Master_Log_Pos' The position in the current master binary log file up to which the I/O thread has read. * `Relay_Log_File' The name of the relay log file from which the SQL thread is currently reading and executing. * `Relay_Log_Pos' The position in the current relay log file up to which the SQL thread has read and executed. * `Relay_Master_Log_File' The name of the master binary log file containing the most recent event executed by the SQL thread. * `Slave_IO_Running' Whether the I/O thread is started and has connected successfully to the master. Internally, the state of this thread is represented by one of the following three values: * `MYSQL_SLAVE_NOT_RUN' The slave I/O thread is not running. For this state, `Slave_IO_Running' is `No'. * `MYSQL_SLAVE_RUN_NOT_CONNECT' The slave I/O thread is running, but is not connected to a replication master. For this state, `Slave_IO_Running' depends on the server version as shown in the following table. MySQL Version `Slave_IO_Running' 4.1 (4.1.13 and earlier); 5.0 `Yes' (5.0.11 and earlier) 4.1 (4.1.14 and later); 5.0 `No' (5.0.12 and later) 5.1 (5.1.45 and earlier); 5.4 `No' 5.1 (5.1.46 and later); 5.5 `Connecting' 6.0 (6.0.10 and earlier) `No' 6.0 (6.0.11 and later) `Connecting' * `MYSQL_SLAVE_RUN_CONNECT' The slave I/O thread is running, and is connected to a replication master. For this state, `Slave_IO_Running' is `Yes'. Beginning with MySQL 5.1.46, the value of the `Slave_running' system status variable corresponds with this value. (Bug#30703) * `Slave_SQL_Running' Whether the SQL thread is started. * `Replicate_Do_DB', `Replicate_Ignore_DB' The lists of databases that were specified with the `--replicate-do-db' and `--replicate-ignore-db' options, if any. * `Replicate_Do_Table', `Replicate_Ignore_Table', `Replicate_Wild_Do_Table', `Replicate_Wild_Ignore_Table' The lists of tables that were specified with the `--replicate-do-table', `--replicate-ignore-table', `--replicate-wild-do-table', and `--replicate-wild-ignore-table' options, if any. * `Last_Errno', `Last_Error' As of MySQL 5.1.20, these columns are aliases for `Last_SQL_Errno' and `Last_SQL_Error'. Before 5.1.20, they indicate the error number and error message returned by the most recently executed statement. An error number of 0 and message of the empty string mean `no error.' If the `Last_Error' value is not empty, the error values also appear in the slave's error log. Beginning with MySQL 5.1.37, and with MySQL Cluster NDB 6.2.17, MySQL Cluster NDB 6.3.23, and MySQL Cluster NDB 6.4.3: Issuing *Note `RESET MASTER': reset-master. or *Note `RESET SLAVE': reset-slave. resets the values shown in these columns. (Bug#34654, Bug#44270) *Note*: When the slave SQL thread receives an error, it reports the error first, then stops the SQL thread. This means that there is a small window of time during which *Note `SHOW SLAVE STATUS': show-slave-status. shows a nonzero value for `Last_SQL_Errno' even though `Slave_SQL_Running' still displays `Yes'. * `Skip_Counter' The current value of the `sql_slave_skip_counter' system variable. See *Note set-global-sql-slave-skip-counter::. * `Exec_Master_Log_Pos' The position in the current master binary file up to which the SQL thread has read and executed. The coordinates given by (`Relay_Master_Log_File', `Exec_Master_Log_Pos') in the master's binary log correspond to the coordinates given by (`Relay_Log_File', `Relay_Log_Pos') in the relay log. * `Relay_Log_Space' The total combined size of all existing relay log files. * `Until_Condition', `Until_Log_File', `Until_Log_Pos' The values specified in the `UNTIL' clause of the *Note `START SLAVE': start-slave. statement. `Until_Condition' has these values: * `None' if no `UNTIL' clause was specified * `Master' if the slave is reading until a given position in the master's binary log * `Relay' if the slave is reading until a given position in its relay log `Until_Log_File' and `Until_Log_Pos' indicate the log file name and position that define the coordinates at which the SQL thread stops executing. * `Master_SSL_Allowed', `Master_SSL_CA_File', `Master_SSL_CA_Path', `Master_SSL_Cert', `Master_SSL_Cipher', `Master_SSL_Key', `Master_SSL_Verify_Server_Cert' These fields show the SSL parameters used by the slave to connect to the master, if any. `Master_SSL_Allowed' has these values: * `Yes' if an SSL connection to the master is permitted * `No' if an SSL connection to the master is not permitted * `Ignored' if an SSL connection is permitted but the slave server does not have SSL support enabled The values of the other SSL-related fields correspond to the values of the `MASTER_SSL_CA', `MASTER_SSL_CAPATH', `MASTER_SSL_CERT', `MASTER_SSL_CIPHER', `MASTER_SSL_KEY', and `MASTER_SSL_VERIFY_SERVER_CERT' options to the *Note `CHANGE MASTER TO': change-master-to. statement. See *Note change-master-to::. `MASTER_SSL_VERIFY_SERVER_CERT' was added in MySQL 5.1.18. * `Seconds_Behind_Master' This field is an indication of how `late' the slave is: * When the slave SQL thread is actively processing updates, this field is the number of seconds that have elapsed since the timestamp of the most recent event on the master executed by that thread. * When the SQL thread has caught up to the slave I/O thread and is idle waiting for more events from the I/O thread, this field is zero. In essence, this field measures the time difference in seconds between the slave SQL thread and the slave I/O thread. If the network connection between master and slave is fast, the slave I/O thread is very close to the master, so this field is a good approximation of how late the slave SQL thread is compared to the master. If the network is slow, this is _not_ a good approximation; the slave SQL thread may quite often be caught up with the slow-reading slave I/O thread, so `Seconds_Behind_Master' often shows a value of 0, even if the I/O thread is late compared to the master. In other words, _this column is useful only for fast networks_. This time difference computation works even though the master and slave do not have identical clocks (the clock difference is computed when the slave I/O thread starts, and assumed to remain constant from then on). `Seconds_Behind_Master' is `NULL' (`unknown') if the slave SQL thread is not running, or if the slave I/O thread is not running or not connected to master. For example, if the slave I/O thread is running but is not connected to the master and is sleeping for the number of seconds given by the *Note `CHANGE MASTER TO': change-master-to. statement or `--master-connect-retry' option (default 60) before reconnecting, the value is `NULL'. This is because the slave cannot know what the master is doing, and so cannot say reliably how late it is. The value of this field is based on the timestamps stored in events, which are preserved through replication. This means that if a master M1 is itself a slave of M0, any event from M1's binary log that originates from M0's binary log has M0's timestamp for that event. This enables MySQL to replicate *Note `TIMESTAMP': datetime. successfully. However, the problem for `Seconds_Behind_Master' is that if M1 also receives direct updates from clients, the `Seconds_Behind_Master' value randomly fluctuates because sometimes the last event from M1 originates from M0 and sometimes is the result of a direct update on M1. * `Last_IO_Errno', `Last_IO_Error' The error number and error message of the last error that caused the I/O thread to stop. An error number of 0 and message of the empty string mean `no error.' If the `Last_IO_Error' value is not empty, the error values also appear in the slave's error log. These columns were added in MySQL 5.1.20. MySQL Cluster Beginning with MySQL Cluster NDB 6.2.17, 6.3.23, and 6.4.3: Issuing *Note `RESET MASTER': reset-master. or *Note `RESET SLAVE': reset-slave. resets the values shown in these columns. This applies to MySQL Cluster only. (Bug#34654) * `Last_SQL_Errno', `Last_SQL_Error' The error number and error message of the last error that caused the SQL thread to stop. An error number of 0 and message of the empty string mean `no error.' If the `Last_SQL_Error' value is not empty, the error values also appear in the slave's error log. These columns were added in MySQL 5.1.20. Example: Last_SQL_Errno: 1051 Last_SQL_Error: error 'Unknown table 'z'' on query 'drop table z' The message indicates that the table `z' existed on the master and was dropped there, but it did not exist on the slave, so *Note `DROP TABLE': drop-table. failed on the slave. (This might occur, for example, if you forget to copy the table to the slave when setting up replication.) MySQL Cluster Beginning with MySQL Cluster NDB 6.2.17, 6.3.23, and 6.4.3: Issuing *Note `RESET MASTER': reset-master. or *Note `RESET SLAVE': reset-slave. resets the values shown in these columns. This applies to MySQL Cluster only. (Bug#34654) * `Replicate_Ignore_Server_Ids' (MySQL Cluster only) Beginning with MySQL Cluster NDB 6.1.29, MySQL Cluster NDB 6.3.31, MySQL Cluster NDB 7.0.11, and MySQL Cluster NDB 7.1.0, you can tell a slave to ignore events from 0 or more masters using the `IGNORE_SERVER_IDS' option in a *Note `CHANGE MASTER TO': change-master-to. statement. (See Bug#47037.) This is normally of interest only when using a circular or other multi-master replication setup. The message shown for `Replicate_Ignore_Server_Ids' consists of a space-delimited list of one or more numbers, the first value indicating the number of servers to be ignored; if not 0 (the default), this server-count value is followed by the actual server IDs. For example, if a *Note `CHANGE MASTER TO': change-master-to. statement containing the `IGNORE_SERVER_IDS = (2,6,9)' option has been issued to tell a slave to ignore masters having the server ID 2, 6, or 9, that information appears as shown here: Replicate_Ignore_Server_Ids: 3 2 6 9  File: manual.info, Node: show-status, Next: show-table-status, Prev: show-slave-status, Up: show 13.4.5.37 `SHOW STATUS' Syntax .............................. SHOW [GLOBAL | SESSION] STATUS [LIKE 'PATTERN' | WHERE EXPR] *Note `SHOW STATUS': show-status. provides server status information. This information also can be obtained using the *Note `mysqladmin extended-status': mysqladmin. command. The `LIKE' clause, if present, indicates which variable names to match. The `WHERE' clause can be given to select rows using more general conditions, as discussed in *Note extended-show::. This statement does not require any privilege. It requires only the ability to connect to the server. Partial output is shown here. The list of names and values may be different for your server. The meaning of each variable is given in *Note server-status-variables::. mysql> SHOW STATUS; +--------------------------+------------+ | Variable_name | Value | +--------------------------+------------+ | Aborted_clients | 0 | | Aborted_connects | 0 | | Bytes_received | 155372598 | | Bytes_sent | 1176560426 | | Connections | 30023 | | Created_tmp_disk_tables | 0 | | Created_tmp_tables | 8340 | | Created_tmp_files | 60 | ... | Open_tables | 1 | | Open_files | 2 | | Open_streams | 0 | | Opened_tables | 44600 | | Questions | 2026873 | ... | Table_locks_immediate | 1920382 | | Table_locks_waited | 0 | | Threads_cached | 0 | | Threads_created | 30022 | | Threads_connected | 1 | | Threads_running | 1 | | Uptime | 80380 | +--------------------------+------------+ With a `LIKE' clause, the statement displays only rows for those variables with names that match the pattern: mysql> SHOW STATUS LIKE 'Key%'; +--------------------+----------+ | Variable_name | Value | +--------------------+----------+ | Key_blocks_used | 14955 | | Key_read_requests | 96854827 | | Key_reads | 162040 | | Key_write_requests | 7589728 | | Key_writes | 3813196 | +--------------------+----------+ With the `GLOBAL' modifier, *Note `SHOW STATUS': show-status. displays the status values for all connections to MySQL. With `SESSION', it displays the status values for the current connection. If no modifier is present, the default is `SESSION'. `LOCAL' is a synonym for `SESSION'. Some status variables have only a global value. For these, you get the same value for both `GLOBAL' and `SESSION'. The scope for each status variable is listed at *Note server-status-variables::. Each invocation of the *Note `SHOW STATUS': show-status. statement uses an internal temporary table and increments the global `Created_tmp_tables' value.  File: manual.info, Node: show-table-status, Next: show-tables, Prev: show-status, Up: show 13.4.5.38 `SHOW TABLE STATUS' Syntax .................................... SHOW TABLE STATUS [{FROM | IN} DB_NAME] [LIKE 'PATTERN' | WHERE EXPR] *Note `SHOW TABLE STATUS': show-table-status. works likes *Note `SHOW TABLES': show-tables, but provides a lot of information about each non-`TEMPORARY' table. You can also get this list using the *Note `mysqlshow --status DB_NAME': mysqlshow. command. The `LIKE' clause, if present, indicates which table names to match. The `WHERE' clause can be given to select rows using more general conditions, as discussed in *Note extended-show::. This statement also displays information about views. *Note `SHOW TABLE STATUS': show-table-status. returns the following fields: * `Name' The name of the table. * `Engine' The storage engine for the table. See *Note storage-engines::. * `Version' The version number of the table's `.frm' file. * `Row_format' The row-storage format (`Fixed', `Dynamic', `Compressed', `Redundant', `Compact'). For `MyISAM' tables, (`Dynamic' corresponds to what *Note `myisamchk -dvv': myisamchk. reports as `Packed'. The format of `InnoDB' tables is reported as `Redundant' or `Compact'. For the `Barracuda' file format of the `InnoDB Plugin', the format may be `Compressed' or `Dynamic'. * `Rows' The number of rows. Some storage engines, such as `MyISAM', store the exact count. For other storage engines, such as `InnoDB', this value is an approximation, and may vary from the actual value by as much as 40 to 50%. In such cases, use `SELECT COUNT(*)' to obtain an accurate count. The `Rows' value is `NULL' for tables in the `INFORMATION_SCHEMA' database. * `Avg_row_length' The average row length. * `Data_length' The length of the data file. * `Max_data_length' The maximum length of the data file. This is the total number of bytes of data that can be stored in the table, given the data pointer size used. * `Index_length' The length of the index file. * `Data_free' The number of allocated but unused bytes. Beginning with MySQL 5.1.24, this information is also shown for `InnoDB' tables (previously, it was in the `Comment' value). `InnoDB' tables report the free space of the tablespace to which the table belongs. For a table located in the shared tablespace, this is the free space of the shared tablespace. If you are using multiple tablespaces and the table has its own tablespace, the free space is for only that table. Free space means the number of completely free 1MB extents minus a safety margin. Even if free space displays as 0, it may be possible to insert rows as long as new extents need not be allocated. For partitioned tables, this value is only an estimate and may not be absolutely correct. A more accurate method of obtaining this information in such cases is to query the `INFORMATION_SCHEMA.PARTITIONS' table, as shown in this example: SELECT SUM(DATA_FREE) FROM INFORMATION_SCHEMA.PARTITIONS WHERE TABLE_SCHEMA = 'mydb' AND TABLE_NAME = 'mytable'; For more information, see *Note partitions-table::. * `Auto_increment' The next `AUTO_INCREMENT' value. * `Create_time' When the table was created. * `Update_time' When the data file was last updated. For some storage engines, this value is `NULL'. For example, `InnoDB' stores multiple tables in its tablespace and the data file timestamp does not apply. For `MyISAM', the data file timestamp is used; however, on Windows the timestamp is not updated by updates so the value is inaccurate. * `Check_time' When the table was last checked. Not all storage engines update this time, in which case the value is always `NULL'. * `Collation' The table's character set and collation. * `Checksum' The live checksum value (if any). * `Create_options' Extra options used with *Note `CREATE TABLE': create-table. The original options supplied when *Note `CREATE TABLE': create-table. is called are retained and the options reported here may differ from the active table settings and options. * `Comment' The comment used when creating the table (or information as to why MySQL could not access the table information). Before MySQL 5.1.24, free space for `InnoDB' tables is reported in the comment. As of 5.1.24, it is reported in the `Data_free' column. For `MEMORY' tables, the `Data_length', `Max_data_length', and `Index_length' values approximate the actual amount of allocated memory. The allocation algorithm reserves memory in large amounts to reduce the number of allocation operations. For *Note `NDBCLUSTER': mysql-cluster. tables, the output of this statement shows appropriate values for the `Avg_row_length' and `Data_length' columns, with the exception that *Note `BLOB': blob. columns are not taken into account. Prior to MySQL 5.1.21, the number of MySQL Cluster replicas was shown in the `Comment' column as `number_of_replicas' (Bug#11379). For views, all the fields displayed by *Note `SHOW TABLE STATUS': show-table-status. are `NULL' except that `Name' indicates the view name and `Comment' says `view'.  File: manual.info, Node: show-tables, Next: show-triggers, Prev: show-table-status, Up: show 13.4.5.39 `SHOW TABLES' Syntax .............................. SHOW [FULL] TABLES [{FROM | IN} DB_NAME] [LIKE 'PATTERN' | WHERE EXPR] *Note `SHOW TABLES': show-tables. lists the non-`TEMPORARY' tables in a given database. You can also get this list using the *Note `mysqlshow DB_NAME': mysqlshow. command. The `LIKE' clause, if present, indicates which table names to match. The `WHERE' clause can be given to select rows using more general conditions, as discussed in *Note extended-show::. This statement also lists any views in the database. The `FULL' modifier is supported such that `SHOW FULL TABLES' displays a second output column. Values for the second column are `BASE TABLE' for a table and `VIEW' for a view. If you have no privileges for a base table or view, it does not show up in the output from *Note `SHOW TABLES': show-tables. or *Note `mysqlshow db_name': mysqlshow.  File: manual.info, Node: show-triggers, Next: show-variables, Prev: show-tables, Up: show 13.4.5.40 `SHOW TRIGGERS' Syntax ................................ SHOW TRIGGERS [{FROM | IN} DB_NAME] [LIKE 'PATTERN' | WHERE EXPR] *Note `SHOW TRIGGERS': show-triggers. lists the triggers currently defined for tables in a database (the default database unless a `FROM' clause is given). This statement returns results only for databases and tables for which you have the `TRIGGER' privilege, or (prior to MySQL 5.1.23) if you have the `SUPER' privilege). The `LIKE' clause, if present, indicates which table names to match and causes the statement to display triggers for those tables. The `WHERE' clause can be given to select rows using more general conditions, as discussed in *Note extended-show::. For the trigger `ins_sum' as defined in *Note triggers::, the output of this statement is as shown here: mysql> SHOW TRIGGERS LIKE 'acc%'\G *************************** 1. row *************************** Trigger: ins_sum Event: INSERT Table: account Statement: SET @sum = @sum + NEW.amount Timing: BEFORE Created: NULL sql_mode: Definer: myname@localhost character_set_client: latin1 collation_connection: latin1_swedish_ci Database Collation: latin1_swedish_ci `character_set_client' is the session value of the `character_set_client' system variable when the trigger was created. `collation_connection' is the session value of the `collation_connection' system variable when the trigger was created. `Database Collation' is the collation of the database with which the trigger is associated. These columns were added in MySQL 5.1.21. *Note*: When using a `LIKE' clause with *Note `SHOW TRIGGERS': show-triggers, the expression to be matched (EXPR) is compared with the name of the table on which the trigger is declared, and not with the name of the trigger: mysql> SHOW TRIGGERS LIKE 'ins%'; Empty set (0.01 sec) A brief explanation of the columns in the output of this statement is shown here: * `Trigger' The name of the trigger. * `Event' The event that causes trigger activation: one of `'INSERT'', `'UPDATE'', or `'DELETE''. * `Table' The table for which the trigger is defined. * `Statement' The statement to be executed when the trigger is activated. This is the same as the text shown in the `ACTION_STATEMENT' column of *Note `INFORMATION_SCHEMA.TRIGGERS': triggers-table. * `Timing' One of the two values `'BEFORE'' or `'AFTER''. * `Created' Currently, the value of this column is always `NULL'. * `sql_mode' The SQL mode in effect when the trigger executes. * `Definer' The account that created the trigger. See also *Note triggers-table::.  File: manual.info, Node: show-variables, Next: show-warnings, Prev: show-triggers, Up: show 13.4.5.41 `SHOW VARIABLES' Syntax ................................. SHOW [GLOBAL | SESSION] VARIABLES [LIKE 'PATTERN' | WHERE EXPR] *Note `SHOW VARIABLES': show-variables. shows the values of MySQL system variables. This information also can be obtained using the *Note `mysqladmin variables': mysqladmin. command. The `LIKE' clause, if present, indicates which variable names to match. The `WHERE' clause can be given to select rows using more general conditions, as discussed in *Note extended-show::. This statement does not require any privilege. It requires only the ability to connect to the server. With the `GLOBAL' modifier, *Note `SHOW VARIABLES': show-variables. displays the values that are used for new connections to MySQL. If a variable has no global value, the session value is displayed. With `SESSION', *Note `SHOW VARIABLES': show-variables. displays the values that are in effect for the current connection. If no modifier is present, the default is `SESSION'. `LOCAL' is a synonym for `SESSION'. *Note `SHOW VARIABLES': show-variables. is subject to a version-dependent display-width limit. For variables with very long values that are not completely displayed, use *Note `SELECT': select. as a workaround. For example: SELECT @@GLOBAL.innodb_data_file_path; If the default system variable values are unsuitable, you can set them using command options when *Note `mysqld': mysqld. starts, and most can be changed at runtime with the *Note `SET': set-option. statement. See *Note using-system-variables::, and *Note set-option::. Partial output is shown here. The list of names and values may be different for your server. *Note server-system-variables::, describes the meaning of each variable, and *Note server-parameters::, provides information about tuning them. mysql> SHOW VARIABLES; +---------------------------------+---------------------------+ | Variable_name | Value | +---------------------------------+---------------------------+ | auto_increment_increment | 1 | | auto_increment_offset | 1 | | automatic_sp_privileges | ON | | back_log | 50 | | basedir | /home/jon/bin/mysql-5.1/ | | binlog_cache_size | 32768 | | bulk_insert_buffer_size | 8388608 | | character_set_client | latin1 | | character_set_connection | latin1 | ... | max_user_connections | 0 | | max_write_lock_count | 4294967295 | | multi_range_count | 256 | | myisam_data_pointer_size | 6 | | myisam_max_sort_file_size | 2147483647 | | myisam_recover_options | OFF | | myisam_repair_threads | 1 | | myisam_sort_buffer_size | 8388608 | | ndb_autoincrement_prefetch_sz | 32 | | ndb_cache_check_time | 0 | | ndb_force_send | ON | ... | time_zone | SYSTEM | | timed_mutexes | OFF | | tmp_table_size | 33554432 | | tmpdir | | | transaction_alloc_block_size | 8192 | | transaction_prealloc_size | 4096 | | tx_isolation | REPEATABLE-READ | | updatable_views_with_limit | YES | | version | 5.1.6-alpha-log | | version_comment | Source distribution | | version_compile_machine | i686 | | version_compile_os | suse-linux | | wait_timeout | 28800 | +---------------------------------+---------------------------+ With a `LIKE' clause, the statement displays only rows for those variables with names that match the pattern. To obtain the row for a specific variable, use a `LIKE' clause as shown: SHOW VARIABLES LIKE 'max_join_size'; SHOW SESSION VARIABLES LIKE 'max_join_size'; To get a list of variables whose name match a pattern, use the ``%'' wildcard character in a `LIKE' clause: SHOW VARIABLES LIKE '%size%'; SHOW GLOBAL VARIABLES LIKE '%size%'; Wildcard characters can be used in any position within the pattern to be matched. Strictly speaking, because ``_'' is a wildcard that matches any single character, you should escape it as ``\_'' to match it literally. In practice, this is rarely necessary.  File: manual.info, Node: show-warnings, Prev: show-variables, Up: show 13.4.5.42 `SHOW WARNINGS' Syntax ................................ SHOW WARNINGS [LIMIT [OFFSET,] ROW_COUNT] SHOW COUNT(*) WARNINGS *Note `SHOW WARNINGS': show-warnings. shows the error, warning, and note messages that resulted from the last statement that generated messages in the current session. It shows nothing if the last statement used a table and generated no messages. (That is, a statement that uses a table but generates no messages clears the message list.) Statements that do not use tables and do not generate messages have no effect on the message list. Warnings are generated for DML statements such as *Note `INSERT': insert, *Note `UPDATE': update, and *Note `LOAD DATA INFILE': load-data. as well as DDL statements such as *Note `CREATE TABLE': create-table. and *Note `ALTER TABLE': alter-table. A related statement, *Note `SHOW ERRORS': show-errors, shows only the errors. See *Note show-errors::. The `SHOW COUNT(*) WARNINGS' statement displays the total number of errors, warnings, and notes. You can also retrieve this number from the `warning_count' variable: SHOW COUNT(*) WARNINGS; SELECT @@warning_count; The value of `warning_count' might be greater than the number of messages displayed by *Note `SHOW WARNINGS': show-warnings. if the `max_error_count' system variable is set so low that not all messages are stored. An example shown later in this section demonstrates how this can happen. The `LIMIT' clause has the same syntax as for the *Note `SELECT': select. statement. See *Note select::. The MySQL server sends back the total number of errors, warnings, and notes resulting from the last statement. If you are using the C API, this value can be obtained by calling *Note `mysql_warning_count()': mysql-warning-count. See *Note mysql-warning-count::. The following *Note `DROP TABLE': drop-table. statement results in a note: mysql> DROP TABLE IF EXISTS no_such_table; mysql> SHOW WARNINGS; +-------+------+-------------------------------+ | Level | Code | Message | +-------+------+-------------------------------+ | Note | 1051 | Unknown table 'no_such_table' | +-------+------+-------------------------------+ Here is a simple example that shows a syntax warning for *Note `CREATE TABLE': create-table. and conversion warnings for *Note `INSERT': insert.: mysql> CREATE TABLE t1 (a TINYINT NOT NULL, b CHAR(4)) TYPE=MyISAM; Query OK, 0 rows affected, 1 warning (0.00 sec) mysql> SHOW WARNINGS\G *************************** 1. row *************************** Level: Warning Code: 1287 Message: 'TYPE=storage_engine' is deprecated, use 'ENGINE=storage_engine' instead 1 row in set (0.00 sec) mysql> INSERT INTO t1 VALUES(10,'mysql'),(NULL,'test'), -> (300,'Open Source'); Query OK, 3 rows affected, 4 warnings (0.01 sec) Records: 3 Duplicates: 0 Warnings: 4 mysql> SHOW WARNINGS\G *************************** 1. row *************************** Level: Warning Code: 1265 Message: Data truncated for column 'b' at row 1 *************************** 2. row *************************** Level: Warning Code: 1263 Message: Data truncated, NULL supplied to NOT NULL column 'a' at row 2 *************************** 3. row *************************** Level: Warning Code: 1264 Message: Data truncated, out of range for column 'a' at row 3 *************************** 4. row *************************** Level: Warning Code: 1265 Message: Data truncated for column 'b' at row 3 4 rows in set (0.00 sec) The maximum number of error, warning, and note messages to store is controlled by the `max_error_count' system variable. By default, its value is 64. To change the number of messages you want stored, change the value of `max_error_count'. In the following example, the *Note `ALTER TABLE': alter-table. statement produces three warning messages, but only one is stored because `max_error_count' has been set to 1: mysql> SHOW VARIABLES LIKE 'max_error_count'; +-----------------+-------+ | Variable_name | Value | +-----------------+-------+ | max_error_count | 64 | +-----------------+-------+ 1 row in set (0.00 sec) mysql> SET max_error_count=1; Query OK, 0 rows affected (0.00 sec) mysql> ALTER TABLE t1 MODIFY b CHAR; Query OK, 3 rows affected, 3 warnings (0.00 sec) Records: 3 Duplicates: 0 Warnings: 3 mysql> SELECT @@warning_count; +-----------------+ | @@warning_count | +-----------------+ | 3 | +-----------------+ 1 row in set (0.01 sec) mysql> SHOW WARNINGS; +---------+------+----------------------------------------+ | Level | Code | Message | +---------+------+----------------------------------------+ | Warning | 1263 | Data truncated for column 'b' at row 1 | +---------+------+----------------------------------------+ 1 row in set (0.00 sec) To disable warnings, set `max_error_count' to 0. In this case, `warning_count' still indicates how many warnings have occurred, but none of the messages are stored. You can set the `sql_notes' session variable to 0 to cause `Note'-level warnings not to be recorded.  File: manual.info, Node: other-administrative-sql, Prev: show, Up: sql-syntax-server-administration 13.4.6 Other Administrative Statements -------------------------------------- * Menu: * binlog:: `BINLOG' Syntax * cache-index:: `CACHE INDEX' Syntax * flush:: `FLUSH' Syntax * kill:: `KILL' Syntax * load-index:: `LOAD INDEX INTO CACHE' Syntax * reset:: `RESET' Syntax  File: manual.info, Node: binlog, Next: cache-index, Prev: other-administrative-sql, Up: other-administrative-sql 13.4.6.1 `BINLOG' Syntax ........................ BINLOG 'STR' *Note `BINLOG': binlog. is an internal-use statement. It is generated by the *Note `mysqlbinlog': mysqlbinlog. program as the printable representation of certain events in binary log files. (See *Note mysqlbinlog::.) The `'STR'' value is a base 64-encoded string the that server decodes to determine the data change indicated by the corresponding event. This statement requires the `SUPER' privilege. It was added in MySQL 5.1.5.  File: manual.info, Node: cache-index, Next: flush, Prev: binlog, Up: other-administrative-sql 13.4.6.2 `CACHE INDEX' Syntax ............................. CACHE INDEX TBL_INDEX_LIST [, TBL_INDEX_LIST] ... IN KEY_CACHE_NAME TBL_INDEX_LIST: TBL_NAME [[INDEX|KEY] (INDEX_NAME[, INDEX_NAME] ...)] The *Note `CACHE INDEX': cache-index. statement assigns table indexes to a specific key cache. It is used only for `MyISAM' tables. After the indexes have been assigned, they can be preloaded into the cache if desired with *Note `LOAD INDEX INTO CACHE': load-index. The following statement assigns indexes from the tables `t1', `t2', and `t3' to the key cache named `hot_cache': mysql> CACHE INDEX t1, t2, t3 IN hot_cache; +---------+--------------------+----------+----------+ | Table | Op | Msg_type | Msg_text | +---------+--------------------+----------+----------+ | test.t1 | assign_to_keycache | status | OK | | test.t2 | assign_to_keycache | status | OK | | test.t3 | assign_to_keycache | status | OK | +---------+--------------------+----------+----------+ The syntax of *Note `CACHE INDEX': cache-index. enables you to specify that only particular indexes from a table should be assigned to the cache. The current implementation assigns all the table's indexes to the cache, so there is no reason to specify anything other than the table name. The key cache referred to in a *Note `CACHE INDEX': cache-index. statement can be created by setting its size with a parameter setting statement or in the server parameter settings. For example: mysql> SET GLOBAL keycache1.key_buffer_size=128*1024; Key cache parameters can be accessed as members of a structured system variable. See *Note structured-system-variables::. A key cache must exist before you can assign indexes to it: mysql> CACHE INDEX t1 IN non_existent_cache; ERROR 1284 (HY000): Unknown key cache 'non_existent_cache' By default, table indexes are assigned to the main (default) key cache created at the server startup. When a key cache is destroyed, all indexes assigned to it become assigned to the default key cache again. Index assignment affects the server globally: If one client assigns an index to a given cache, this cache is used for all queries involving the index, no matter which client issues the queries.  File: manual.info, Node: flush, Next: kill, Prev: cache-index, Up: other-administrative-sql 13.4.6.3 `FLUSH' Syntax ....................... FLUSH [NO_WRITE_TO_BINLOG | LOCAL] FLUSH_OPTION [, FLUSH_OPTION] ... The *Note `FLUSH': flush. statement clears or reloads various internal caches used by MySQL. One variant acquires a lock. To execute *Note `FLUSH': flush, you must have the `RELOAD' privilege. By default, *Note `FLUSH': flush. statements are written to the binary log so that they will be replicated to replication slaves. Logging can be suppressed with the optional `NO_WRITE_TO_BINLOG' keyword or its alias `LOCAL'. *Note*: *Note `FLUSH LOGS': flush, *Note `FLUSH MASTER': flush, *Note `FLUSH SLAVE': flush, and *Note `FLUSH TABLES WITH READ LOCK': flush. are not written to the binary log in any case because they would cause problems if replicated to a slave. The *Note `RESET': reset. statement is similar to *Note `FLUSH': flush. See *Note reset::, for information about using the *Note `RESET': reset. statement with replication. FLUSH_OPTION can be any of the following items: * `DES_KEY_FILE' Reloads the DES keys from the file that was specified with the `--des-key-file' option at server startup time. * `HOSTS' Empties the host cache tables. You should flush the host tables if some of your hosts change IP address or if you get the error message `Host 'HOST_NAME' is blocked'. When more than `max_connect_errors' errors occur successively for a given host while connecting to the MySQL server, MySQL assumes that something is wrong and blocks the host from further connection requests. Flushing the host tables enables further connection attempts from the host. See *Note blocked-host::. You can start *Note `mysqld': mysqld. with `--max_connect_errors=999999999' to avoid this error message. * `LOGS' Closes and reopens all log files. If binary logging is enabled, the sequence number of the binary log file is incremented by one relative to the previous file. On Unix, this is the same thing as sending a `SIGHUP' signal to the *Note `mysqld': mysqld. server (except on some Mac OS X 10.3 versions where *Note `mysqld': mysqld. ignores `SIGHUP' and `SIGQUIT'). Prior to MySQL 5.1.51, if you flush the logs using *Note `FLUSH LOGS': flush. and *Note `mysqld': mysqld. is writing the error log to a file (for example, if it was started with the `--log-error' option), log file renaming may occur, as described in *Note error-log::. * `MASTER' Deletes all binary logs, resets the binary log index file and creates a new binary log. *Note `FLUSH MASTER': flush. is deprecated in favor of *Note `RESET MASTER': reset-master. *Note `FLUSH MASTER': flush. is still accepted in MySQL 5.1 for backward compatibility, but is removed in MySQL 5.6. See *Note reset-master::. * `PRIVILEGES' Reloads the privileges from the grant tables in the `mysql' database. On Unix, this also occurs if the server receives a `SIGHUP' signal. The server caches information in memory as a result of *Note `GRANT': grant, *Note `CREATE USER': create-user, *Note `CREATE SERVER': create-server, and *Note `INSTALL PLUGIN': install-plugin. statements. This memory is not released by the corresponding *Note `REVOKE': revoke, *Note `DROP USER': drop-user, *Note `DROP SERVER': drop-server, and *Note `UNINSTALL PLUGIN': uninstall-plugin. statements, so for a server that executes many instances of the statements that cause caching, there will be an increase in memory use. This cached memory can be freed with *Note `FLUSH PRIVILEGES': flush. * `QUERY CACHE' Defragment the query cache to better utilize its memory. *Note `FLUSH QUERY CACHE': flush. does not remove any queries from the cache, unlike *Note `FLUSH TABLES': flush. or `RESET QUERY CACHE'. * `SLAVE' Resets all replication slave parameters, including relay log files and replication position in the master's binary logs. *Note `FLUSH SLAVE': flush. is deprecated in favor of *Note `RESET SLAVE': reset-slave. *Note `FLUSH SLAVE': flush. is still accepted in MySQL 5.1 for backward compatibility, but is removed in MySQL 5.6. See *Note reset-slave::. * `STATUS' This option adds the current thread's session status variable values to the global values and resets the session values to zero. It also resets the counters for key caches (default and named) to zero and sets `Max_used_connections' to the current number of open connections. This is something you should use only when debugging a query. See *Note bug-reports::. * `TABLES' *Note `FLUSH TABLES': flush. has several variant forms. *Note `FLUSH TABLE': flush. is a synonym for *Note `FLUSH TABLES': flush, except that `TABLE' does not work with the `WITH READ LOCK' variant. * `FLUSH TABLES' Closes all open tables, forces all tables in use to be closed, and flushes the query cache. *Note `FLUSH TABLES': flush. also removes all query results from the query cache, like the `RESET QUERY CACHE' statement. * `FLUSH TABLES TBL_NAME [, TBL_NAME] ...' With a list of one or more comma-separated table names, this is like *Note `FLUSH TABLES': flush. with no names except that the server flushes only the named tables. No error occurs if a named table does not exist. * `FLUSH TABLES WITH READ LOCK' Closes all open tables and locks all tables for all databases with a global read lock until you explicitly release the lock by executing *Note `UNLOCK TABLES': lock-tables. This is a very convenient way to get backups if you have a file system such as Veritas or ZFS that can take snapshots in time. *Note `FLUSH TABLES WITH READ LOCK': flush. acquires a global read lock and not table locks, so it is not subject to the same behavior as *Note `LOCK TABLES': lock-tables. and *Note `UNLOCK TABLES': lock-tables. with respect to table locking and implicit commits: * *Note `UNLOCK TABLES': lock-tables. implicitly commits any active transaction only if any tables currently have been locked with *Note `LOCK TABLES': lock-tables. The commit does not occur for *Note `UNLOCK TABLES': lock-tables. following *Note `FLUSH TABLES WITH READ LOCK': flush. because the latter statement does not acquire table locks. * Beginning a transaction causes table locks acquired with *Note `LOCK TABLES': lock-tables. to be released, as though you had executed *Note `UNLOCK TABLES': lock-tables. Beginning a transaction does not release a global read lock acquired with *Note `FLUSH TABLES WITH READ LOCK': flush. *Note `FLUSH TABLES WITH READ LOCK': flush. does not prevent the server from inserting rows into the log tables (see *Note log-destinations::). * `USER_RESOURCES' Resets all per-hour user resources to zero. This enables clients that have reached their hourly connection, query, or update limits to resume activity immediately. *Note `FLUSH USER_RESOURCES': flush. does not apply to the limit on maximum simultaneous connections. See *Note user-resources::. The *Note `mysqladmin': mysqladmin. utility provides a command-line interface to some flush operations, using commands such as `flush-hosts', `flush-logs', `flush-privileges', `flush-status', and `flush-tables'. *Note*: It is not possible in MySQL 5.1 to issue *Note `FLUSH': flush. statements within stored functions or triggers. However, you may use *Note `FLUSH': flush. in stored procedures, so long as these are not called from stored functions or triggers. See *Note stored-program-restrictions::.  File: manual.info, Node: kill, Next: load-index, Prev: flush, Up: other-administrative-sql 13.4.6.4 `KILL' Syntax ...................... KILL [CONNECTION | QUERY] THREAD_ID Each connection to *Note `mysqld': mysqld. runs in a separate thread. You can see which threads are running with the *Note `SHOW PROCESSLIST': show-processlist. statement and kill a thread with the `KILL THREAD_ID' statement. *Note `KILL': kill. permits an optional `CONNECTION' or `QUERY' modifier: * *Note `KILL CONNECTION': kill. is the same as *Note `KILL': kill. with no modifier: It terminates the connection associated with the given THREAD_ID. * *Note `KILL QUERY': kill. terminates the statement that the connection is currently executing, but leaves the connection itself intact. If you have the `PROCESS' privilege, you can see all threads. If you have the `SUPER' privilege, you can kill all threads and statements. Otherwise, you can see and kill only your own threads and statements. You can also use the *Note `mysqladmin processlist': mysqladmin. and *Note `mysqladmin kill': mysqladmin. commands to examine and kill threads. *Note*: You cannot use *Note `KILL': kill. with the Embedded MySQL Server library because the embedded server merely runs inside the threads of the host application. It does not create any connection threads of its own. When you use *Note `KILL': kill, a thread-specific kill flag is set for the thread. In most cases, it might take some time for the thread to die because the kill flag is checked only at specific intervals: * In *Note `SELECT': select, `ORDER BY' and `GROUP BY' loops, the flag is checked after reading a block of rows. If the kill flag is set, the statement is aborted. * During *Note `ALTER TABLE': alter-table, the kill flag is checked before each block of rows are read from the original table. If the kill flag was set, the statement is aborted and the temporary table is deleted. * During *Note `UPDATE': update. or *Note `DELETE': delete. operations, the kill flag is checked after each block read and after each updated or deleted row. If the kill flag is set, the statement is aborted. Note that if you are not using transactions, the changes are not rolled back. * `GET_LOCK()' aborts and returns `NULL'. * An *Note `INSERT DELAYED': insert-delayed. thread quickly flushes (inserts) all rows it has in memory and then terminates. * If the thread is in the table lock handler (state: `Locked'), the table lock is quickly aborted. * If the thread is waiting for free disk space in a write call, the write is aborted with a `disk full' error message. * *Warning*: Killing a *Note `REPAIR TABLE': repair-table. or *Note `OPTIMIZE TABLE': optimize-table. operation on a `MyISAM' table results in a table that is corrupted and unusable. Any reads or writes to such a table fail until you optimize or repair it again (without interruption).  File: manual.info, Node: load-index, Next: reset, Prev: kill, Up: other-administrative-sql 13.4.6.5 `LOAD INDEX INTO CACHE' Syntax ....................................... LOAD INDEX INTO CACHE TBL_INDEX_LIST [, TBL_INDEX_LIST] ... TBL_INDEX_LIST: TBL_NAME [[INDEX|KEY] (INDEX_NAME[, INDEX_NAME] ...)] [IGNORE LEAVES] The *Note `LOAD INDEX INTO CACHE': load-index. statement preloads a table index into the key cache to which it has been assigned by an explicit *Note `CACHE INDEX': cache-index. statement, or into the default key cache otherwise. *Note `LOAD INDEX INTO CACHE': load-index. is used only for `MyISAM' tables. It is not supported for tables having user-defined partitioning (see *Note partitioning-limitations::.) The `IGNORE LEAVES' modifier causes only blocks for the nonleaf nodes of the index to be preloaded. The following statement preloads nodes (index blocks) of indexes for the tables `t1' and `t2': mysql> LOAD INDEX INTO CACHE t1, t2 IGNORE LEAVES; +---------+--------------+----------+----------+ | Table | Op | Msg_type | Msg_text | +---------+--------------+----------+----------+ | test.t1 | preload_keys | status | OK | | test.t2 | preload_keys | status | OK | +---------+--------------+----------+----------+ This statement preloads all index blocks from `t1'. It preloads only blocks for the nonleaf nodes from `t2'. The syntax of *Note `LOAD INDEX INTO CACHE': load-index. enables you to specify that only particular indexes from a table should be preloaded. The current implementation preloads all the table's indexes into the cache, so there is no reason to specify anything other than the table name. *Note `LOAD INDEX INTO CACHE ... IGNORE LEAVES': load-index. fails unless all indexes in a table have the same block size. (Prior to MySQL 5.1.19, it fails even without `IGNORE LEAVES'.) You can determine index block sizes for a table by using *Note `myisamchk -dv': myisamchk. and checking the `Blocksize' column.  File: manual.info, Node: reset, Prev: load-index, Up: other-administrative-sql 13.4.6.6 `RESET' Syntax ....................... RESET RESET_OPTION [, RESET_OPTION] ... The *Note `RESET': reset. statement is used to clear the state of various server operations. You must have the `RELOAD' privilege to execute *Note `RESET': reset. *Note `RESET': reset. acts as a stronger version of the *Note `FLUSH': flush. statement. See *Note flush::. RESET_OPTION can be any of the following: * `MASTER' Deletes all binary logs listed in the index file, resets the binary log index file to be empty, and creates a new binary log file. * `QUERY CACHE' Removes all query results from the query cache. * `SLAVE' Makes the slave forget its replication position in the master binary logs. Also resets the relay log by deleting any existing relay log files and beginning a new one.  File: manual.info, Node: sql-syntax-replication, Next: sql-syntax-prepared-statements, Prev: sql-syntax-server-administration, Up: sql-syntax 13.5 Replication Statements =========================== * Menu: * replication-master-sql:: SQL Statements for Controlling Master Servers * replication-slave-sql:: SQL Statements for Controlling Slave Servers Replication can be controlled through the SQL interface using the statements described in this section. One group of statements controls master servers, the other controls slave servers.  File: manual.info, Node: replication-master-sql, Next: replication-slave-sql, Prev: sql-syntax-replication, Up: sql-syntax-replication 13.5.1 SQL Statements for Controlling Master Servers ---------------------------------------------------- * Menu: * purge-binary-logs:: `PURGE BINARY LOGS' Syntax * reset-master:: `RESET MASTER' Syntax * set-sql-log-bin:: `SET sql_log_bin' Syntax This section discusses statements for managing master replication servers. *Note replication-slave-sql::, discusses statements for managing slave servers. In addition to the statements described here, the following *Note `SHOW': show. statements are used with master servers in replication. For information about these statements, see *Note show::. * *Note `SHOW BINARY LOGS': show-binary-logs. * *Note `SHOW BINLOG EVENTS': show-binlog-events. * *Note `SHOW MASTER STATUS': show-master-status. * *Note `SHOW SLAVE HOSTS': show-slave-hosts.  File: manual.info, Node: purge-binary-logs, Next: reset-master, Prev: replication-master-sql, Up: replication-master-sql 13.5.1.1 `PURGE BINARY LOGS' Syntax ................................... PURGE { BINARY | MASTER } LOGS { TO 'LOG_NAME' | BEFORE DATETIME_EXPR } The binary log is a set of files that contain information about data modifications made by the MySQL server. The log consists of a set of binary log files, plus an index file (see *Note binary-log::). The *Note `PURGE BINARY LOGS': purge-binary-logs. statement deletes all the binary log files listed in the log index file prior to the specified log file name or date. `BINARY' and `MASTER' are synonyms. Deleted log files also are removed from the list recorded in the index file, so that the given log file becomes the first in the list. This statement has no effect if the server was not started with the `--log-bin' option to enable binary logging. Examples: PURGE BINARY LOGS TO 'mysql-bin.010'; PURGE BINARY LOGS BEFORE '2008-04-02 22:46:26'; The `BEFORE' variant's DATETIME_EXPR argument should evaluate to a *Note `DATETIME': datetime. value (a value in `'YYYY-MM-DD hh:mm:ss'' format). This statement is safe to run while slaves are replicating. You need not stop them. If you have an active slave that currently is reading one of the log files you are trying to delete, this statement does nothing and fails with an error. However, if a slave is not connected and you happen to purge one of the log files it has yet to read, the slave will be unable to replicate after it reconnects. To safely purge binary log files, follow this procedure: 1. On each slave server, use *Note `SHOW SLAVE STATUS': show-slave-status. to check which log file it is reading. 2. Obtain a listing of the binary log files on the master server with *Note `SHOW BINARY LOGS': show-binary-logs. 3. Determine the earliest log file among all the slaves. This is the target file. If all the slaves are up to date, this is the last log file on the list. 4. Make a backup of all the log files you are about to delete. (This step is optional, but always advisable.) 5. Purge all log files up to but not including the target file. You can also set the `expire_logs_days' system variable to expire binary log files automatically after a given number of days (see *Note server-system-variables::). If you are using replication, you should set the variable no lower than the maximum number of days your slaves might lag behind the master. Prior to MySQL 5.1.24, `PURGE BINARY LOGS TO' and `PURGE BINARY LOGS BEFORE' did not behave in the same way (and neither one behaved correctly) when binary log files listed in the `.index' file had been removed from the system by some other means (such as using `rm' on Linux). Beginning with MySQL 5.1.24, both variants of the statement fail with an error in such cases. (Bug#18199, Bug#18453) To handle such errors, edit the `.index' file (which is a simple text file) manually to ensure that it lists only the binary log files that are actually present, then run again the *Note `PURGE BINARY LOGS': purge-binary-logs. statement that failed.  File: manual.info, Node: reset-master, Next: set-sql-log-bin, Prev: purge-binary-logs, Up: replication-master-sql 13.5.1.2 `RESET MASTER' Syntax .............................. RESET MASTER Deletes all binary log files listed in the index file, resets the binary log index file to be empty, and creates a new binary log file. This statement is intended to be used only when the master is started for the first time. *Important*: The effects of *Note `RESET MASTER': reset-master. differ from those of *Note `PURGE BINARY LOGS': purge-binary-logs. in 2 key ways: 1. *Note `RESET MASTER': reset-master. removes _all_ binary log files that are listed in the index file, leaving only a single, empty binary log file with a numeric suffix of `.000001', whereas the numbering is not reset by *Note `PURGE BINARY LOGS': purge-binary-logs. 2. *Note `RESET MASTER': reset-master. is _not_ intended to be used while any replication slaves are running. The behavior of *Note `RESET MASTER': reset-master. when used while slaves are running is undefined (and thus unsupported), whereas *Note `PURGE BINARY LOGS': purge-binary-logs. may be safely used while replication slaves are running. See also *Note purge-binary-logs::. *Note `RESET MASTER': reset-master. can prove useful when you first set up the master and the slave, so that you can verify the setup as follows: 1. Start the master and slave, and start replication (see *Note replication-howto::). 2. Execute a few test queries on the master. 3. Check that the queries were replicated to the slave. 4. When replication is running correctly, issue *Note `STOP SLAVE': stop-slave. followed by *Note `RESET SLAVE': reset-slave. on the slave, then verify that any unwanted data no longer exists on the slave. 5. Issue *Note `RESET MASTER': reset-master. on the master to clean up the test queries. After verifying the setup and getting rid of any unwanted and log files generated by testing, you can start the slave and begin replicating.  File: manual.info, Node: set-sql-log-bin, Prev: reset-master, Up: replication-master-sql 13.5.1.3 `SET sql_log_bin' Syntax ................................. SET sql_log_bin = {0|1} Disables or enables binary logging for the current session (`sql_log_bin' is a session variable) if the client has the `SUPER' privilege. The statement fails with an error if the client does not have that privilege.  File: manual.info, Node: replication-slave-sql, Prev: replication-master-sql, Up: sql-syntax-replication 13.5.2 SQL Statements for Controlling Slave Servers --------------------------------------------------- * Menu: * change-master-to:: `CHANGE MASTER TO' Syntax * load-data-from-master:: `LOAD DATA FROM MASTER' Syntax * load-table-from-master:: `LOAD TABLE TBL_NAME FROM MASTER' Syntax * master-pos-wait:: `MASTER_POS_WAIT()' Syntax * reset-slave:: `RESET SLAVE' Syntax * set-global-sql-slave-skip-counter:: `SET GLOBAL sql_slave_skip_counter' Syntax * start-slave:: `START SLAVE' Syntax * stop-slave:: `STOP SLAVE' Syntax This section discusses statements for managing slave replication servers. *Note replication-master-sql::, discusses statements for managing master servers. In addition to the statements described here, *Note `SHOW SLAVE STATUS': show-slave-status. is also used with replication slaves. For information about this statement, see *Note show-slave-status::.  File: manual.info, Node: change-master-to, Next: load-data-from-master, Prev: replication-slave-sql, Up: replication-slave-sql 13.5.2.1 `CHANGE MASTER TO' Syntax .................................. CHANGE MASTER TO OPTION [, OPTION] ... OPTION: MASTER_BIND = 'INTERFACE_NAME' | MASTER_HOST = 'HOST_NAME' | MASTER_USER = 'USER_NAME' | MASTER_PASSWORD = 'PASSWORD' | MASTER_PORT = PORT_NUM | MASTER_CONNECT_RETRY = INTERVAL | MASTER_HEARTBEAT_PERIOD = INTERVAL | MASTER_LOG_FILE = 'MASTER_LOG_NAME' | MASTER_LOG_POS = MASTER_LOG_POS | RELAY_LOG_FILE = 'RELAY_LOG_NAME' | RELAY_LOG_POS = RELAY_LOG_POS | MASTER_SSL = {0|1} | MASTER_SSL_CA = 'CA_FILE_NAME' | MASTER_SSL_CAPATH = 'CA_DIRECTORY_NAME' | MASTER_SSL_CERT = 'CERT_FILE_NAME' | MASTER_SSL_KEY = 'KEY_FILE_NAME' | MASTER_SSL_CIPHER = 'CIPHER_LIST' | MASTER_SSL_VERIFY_SERVER_CERT = {0|1} | IGNORE_SERVER_IDS = (SERVER_ID_LIST) SERVER_ID_LIST: [SERVER_ID [, SERVER_ID] ... ] *Note `CHANGE MASTER TO': change-master-to. changes the parameters that the slave server uses for connecting to the master server, for reading the master binary log, and reading the slave relay log. It also updates the contents of the `master.info' and `relay-log.info' files. To use *Note `CHANGE MASTER TO': change-master-to, the slave replication threads must be stopped (use *Note `STOP SLAVE': stop-slave. if necessary). Options not specified retain their value, except as indicated in the following discussion. Thus, in most cases, there is no need to specify options that do not change. For example, if the password to connect to your MySQL master has changed, you just need to issue these statements to tell the slave about the new password: STOP SLAVE; -- if replication was running CHANGE MASTER TO MASTER_PASSWORD='new3cret'; START SLAVE; -- if you want to restart replication `MASTER_HOST', `MASTER_USER', `MASTER_PASSWORD', and `MASTER_PORT' provide information to the slave about how to connect to its master: * `MASTER_HOST' and `MASTER_PORT' are the host name (or IP address) of the master host and its TCP/IP port. *Note*: Replication cannot use Unix socket files. You must be able to connect to the master MySQL server using TCP/IP. If you specify the `MASTER_HOST' or `MASTER_PORT' option, the slave assumes that the master server is different from before (even if the option value is the same as its current value.) In this case, the old values for the master binary log file name and position are considered no longer applicable, so if you do not specify `MASTER_LOG_FILE' and `MASTER_LOG_POS' in the statement, `MASTER_LOG_FILE=''' and `MASTER_LOG_POS=4' are silently appended to it. Setting `MASTER_HOST=''' (that is, setting its value explicitly to an empty string) is _not_ the same as not setting `MASTER_HOST' at all. Setting this option to an empty string causes *Note `START SLAVE': start-slave. subsequently to fail. This issue is addressed in MySQL 5.5. (Bug#28796) * `MASTER_USER' and `MASTER_PASSWORD' are the user name and password of the account to use for connecting to the master. The `MASTER_SSL_XXX' options provide information about using SSL for the connection. They correspond to the `--ssl-XXX' options described in *Note ssl-options::, and *Note replication-solutions-ssl::. `MASTER_SSL_VERIFY_SERVER_CERT' was added in MySQL 5.1.18. These options can be changed even on slaves that are compiled without SSL support. They are saved to the `master.info' file, but are ignored if the slave does not have SSL support enabled. `MASTER_CONNECT_RETRY' specifies how many seconds to wait between connect retries. The default is 60. The _number_ of reconnection attempts is limited by the `--master-retry-count' server option; for more information, see *Note replication-options::. The next two options (`MASTER_BIND' and `MASTER_HEARTBEAT_PERIOD') are available in MySQL Cluster NDB 6.3 and later, but are not supported in mainline MySQL 5.1: `MASTER_BIND' is for use on replication slaves having multiple network interfaces, and determines which of the slave's network interfaces is chosen for connecting to the master. It is also possible to determine which network interface is to be used in such cases by starting the slave mysqld process with the `--master-bind' option. The ability to bind a replication slave to specific network interface was added in MySQL Cluster NDB 6.3.4. `MASTER_HEARTBEAT_PERIOD' is used to set the interval in seconds between replication heartbeats. Whenever the master's binary log is updated with an event, the waiting period for the next heartbeat is reset. INTERVAL is a decimal value having the range 0 to 4294967 seconds and a resolution in milliseconds; the smallest nonzero value is 0.001. Heartbeats are sent by the master only if there are no unsent events in the binary log file for a period longer than INTERVAL. Setting INTERVAL to 0 disables heartbeats altogether. The default value for INTERVAL is equal to the value of `slave_net_timeout' divided by 2. Setting `@@global.slave_net_timeout' to a value less than that of the current heartbeat interval results in a warning being issued. The effect of issuing *Note `RESET SLAVE': reset-slave. on the heartbeat interval is to reset it to the default value. `MASTER_HEARTBEAT_PERIOD' was added in MySQL Cluster NDB 6.3.4. `MASTER_LOG_FILE' and `MASTER_LOG_POS' are the coordinates at which the slave I/O thread should begin reading from the master the next time the thread starts. `RELAY_LOG_FILE' and `RELAY_LOG_POS' are the coordinates at which the slave SQL thread should begin reading from the relay log the next time the thread starts. If you specify either of `MASTER_LOG_FILE' or `MASTER_LOG_POS', you cannot specify `RELAY_LOG_FILE' or `RELAY_LOG_POS'. If neither of `MASTER_LOG_FILE' or `MASTER_LOG_POS' is specified, the slave uses the last coordinates of the _slave SQL thread_ before *Note `CHANGE MASTER TO': change-master-to. was issued. This ensures that there is no discontinuity in replication, even if the slave SQL thread was late compared to the slave I/O thread, when you merely want to change, say, the password to use. *Note `CHANGE MASTER TO': change-master-to. _deletes all relay log files_ and starts a new one, unless you specify `RELAY_LOG_FILE' or `RELAY_LOG_POS'. In that case, relay log files are kept; the `relay_log_purge' global variable is set silently to 0. `IGNORE_SERVER_IDS' was added in MySQL Cluster NDB 6.1.29, MySQL Cluster NDB 6.3.31, MySQL Cluster NDB 7.0.11, and MySQL Cluster NDB 7.1.0 (see Bug#47037). This option takes a comma-separated list of 0 or more server IDs. Events originating from the corresponding servers are ignored, with the exception of log rotation and deletion events, which are still recorded in the relay log. In circular replication, the originating server normally acts as the terminator of its own events, so that they are not applied more than once. Thus, this option is useful in circular replication when one of the servers in the circle is removed. Suppose that you have a circular replication setup with 4 servers, having server IDs 1, 2, 3, and 4, and server 3 fails. When bridging the gap by starting replication from server 2 to server 4, you can include `IGNORE_SERVER_IDS = (3)' in the *Note `CHANGE MASTER TO': change-master-to. statement that you issue on server 4 to tell it to use server 2 as its master instead of server 3. Doing so causes it to ignore and not to propagate any statements that originated with the server that is no longer in use. If a *Note `CHANGE MASTER TO': change-master-to. statement is issued without any `IGNORE_SERVER_IDS' option, any existing list is preserved; *Note `RESET SLAVE': reset-slave. also has no effect on the server ID list. To clear the list of ignored servers, it is necessary to use the option with an empty list: CHANGE MASTER TO IGNORE_SERVER_IDS = (); If `IGNORE_SERVER_IDS' contains the server's own ID and the server was started with the `--replicate-same-server-id' option enabled, an error results. Beginning with MySQL 5.1.47, invoking *Note `CHANGE MASTER TO': change-master-to. causes the previous values for `MASTER_HOST', `MASTER_PORT', `MASTER_LOG_FILE', and `MASTER_LOG_POS' to be written to the error log, along with other information about the slave's state prior to execution. *Note `CHANGE MASTER TO': change-master-to. is useful for setting up a slave when you have the snapshot of the master and have recorded the master binary log coordinates corresponding to the time of the snapshot. After loading the snapshot into the slave to synchronize it to the slave, you can run `CHANGE MASTER TO MASTER_LOG_FILE='LOG_NAME', MASTER_LOG_POS=LOG_POS' on the slave to specify the coordinates at which the slave should begin reading the master binary log. The following example changes the master server the slave uses and establishes the master binary log coordinates from which the slave begins reading. This is used when you want to set up the slave to replicate the master: CHANGE MASTER TO MASTER_HOST='master2.mycompany.com', MASTER_USER='replication', MASTER_PASSWORD='bigs3cret', MASTER_PORT=3306, MASTER_LOG_FILE='master2-bin.001', MASTER_LOG_POS=4, MASTER_CONNECT_RETRY=10; The next example shows an operation that is less frequently employed. It is used when the slave has relay log files that you want it to execute again for some reason. To do this, the master need not be reachable. You need only use *Note `CHANGE MASTER TO': change-master-to. and start the SQL thread (`START SLAVE SQL_THREAD'): CHANGE MASTER TO RELAY_LOG_FILE='slave-relay-bin.006', RELAY_LOG_POS=4025; You can even use the second operation in a nonreplication setup with a standalone, nonslave server for recovery following a crash. Suppose that your server has crashed and you have restored it from a backup. You want to replay the server's own binary log files (not relay log files, but regular binary log files), named (for example) `myhost-bin.*'. First, make a backup copy of these binary log files in some safe place, in case you don't exactly follow the procedure below and accidentally have the server purge the binary log. Use `SET GLOBAL relay_log_purge=0' for additional safety. Then start the server without the `--log-bin' option, Instead, use the `--replicate-same-server-id', `--relay-log=myhost-bin' (to make the server believe that these regular binary log files are relay log files) and `--skip-slave-start' options. After the server starts, issue these statements: CHANGE MASTER TO RELAY_LOG_FILE='myhost-bin.153', RELAY_LOG_POS=410, MASTER_HOST='some_dummy_string'; START SLAVE SQL_THREAD; The server reads and executes its own binary log files, thus achieving crash recovery. Once the recovery is finished, run *Note `STOP SLAVE': stop-slave, shut down the server, delete the `master.info' and `relay-log.info' files, and restart the server with its original options. Specifying the `MASTER_HOST' option (even with a dummy value) is required to make the server think it is a slave. The following table shows the maximum permissible length for the string-valued options. Option Maximum Length `MASTER_HOST' 60 `MASTER_USER' 16 `MASTER_PASSWORD'32 `MASTER_LOG_FILE'255 `RELAY_LOG_FILE'255 `MASTER_SSL_CA'255 `MASTER_SSL_CAPATH'255 `MASTER_SSL_CERT'255 `MASTER_SSL_KEY'255 `MASTER_SSL_CIPHER'511  File: manual.info, Node: load-data-from-master, Next: load-table-from-master, Prev: change-master-to, Up: replication-slave-sql 13.5.2.2 `LOAD DATA FROM MASTER' Syntax ....................................... LOAD DATA FROM MASTER *This feature is deprecated and should be avoided. It is subject to removal in a future version of MySQL.* Since the current implementation of `LOAD DATA FROM MASTER' and `LOAD TABLE FROM MASTER' is very limited, these statements are deprecated as of MySQL 4.1 and removed in MySQL 5.5. The recommended alternative solution to using `LOAD DATA FROM MASTER' or `LOAD TABLE FROM MASTER' is using *Note `mysqldump': mysqldump. or *Note `mysqlhotcopy': mysqlhotcopy. The latter requires Perl and two Perl modules (`DBI' and `DBD:mysql') and works for `MyISAM' and `ARCHIVE' tables only. With *Note `mysqldump': mysqldump, you can create SQL dumps on the master and pipe (or copy) these to a *Note `mysql': mysql. client on the slave. This has the advantage of working for all storage engines, but can be quite slow, since it works using *Note `SELECT': select. This statement takes a snapshot of the master and copies it to the slave. It updates the values of `MASTER_LOG_FILE' and `MASTER_LOG_POS' so that the slave starts replicating from the correct position. Any table and database exclusion rules specified with the `--replicate-*-do-*' and `--replicate-*-ignore-*' options are honored. `--replicate-rewrite-db' is _not_ taken into account because a user could use this option to set up a nonunique mapping such as `--replicate-rewrite-db="db1->db3"' and `--replicate-rewrite-db="db2->db3"', which would confuse the slave when loading tables from the master. Use of this statement is subject to the following conditions: * It works only for `MyISAM' tables. Attempting to load a non-`MyISAM' table results in the following error: ERROR 1189 (08S01): Net error reading from master * It acquires a global read lock on the master while taking the snapshot, which prevents updates on the master during the load operation. If you are loading large tables, you might have to increase the values of `net_read_timeout' and `net_write_timeout' on both the master and slave servers. See *Note server-system-variables::. Note that `LOAD DATA FROM MASTER' does _not_ copy any tables from the `mysql' database. This makes it easy to have different users and privileges on the master and the slave. To use `LOAD DATA FROM MASTER', the replication account that is used to connect to the master must have the `RELOAD' and `SUPER' privileges on the master and the `SELECT' privilege for all master tables you want to load. All master tables for which the user does not have the *Note `SELECT': select. privilege are ignored by `LOAD DATA FROM MASTER'. This is because the master hides them from the user: `LOAD DATA FROM MASTER' calls *Note `SHOW DATABASES': show-databases. to know the master databases to load, but *Note `SHOW DATABASES': show-databases. returns only databases for which the user has some privilege. See *Note show-databases::. On the slave side, the user that issues `LOAD DATA FROM MASTER' must have privileges for dropping and creating the databases and tables that are copied.  File: manual.info, Node: load-table-from-master, Next: master-pos-wait, Prev: load-data-from-master, Up: replication-slave-sql 13.5.2.3 `LOAD TABLE TBL_NAME FROM MASTER' Syntax ................................................. LOAD TABLE TBL_NAME FROM MASTER *This feature is deprecated and should be avoided. It is subject to removal in a future version of MySQL.* Since the current implementation of `LOAD DATA FROM MASTER' and `LOAD TABLE FROM MASTER' is very limited, these statements are deprecated as of MySQL 4.1 and removed in MySQL 5.5. The recommended alternative solution to using `LOAD DATA FROM MASTER' or `LOAD TABLE FROM MASTER' is using *Note `mysqldump': mysqldump. or *Note `mysqlhotcopy': mysqlhotcopy. The latter requires Perl and two Perl modules (`DBI' and `DBD:mysql') and works for `MyISAM' and `ARCHIVE' tables only. With *Note `mysqldump': mysqldump, you can create SQL dumps on the master and pipe (or copy) these to a *Note `mysql': mysql. client on the slave. This has the advantage of working for all storage engines, but can be quite slow, since it works using *Note `SELECT': select. Transfers a copy of the table from the master to the slave. This statement is implemented mainly debugging `LOAD DATA FROM MASTER' operations. To use `LOAD TABLE', the account used for connecting to the master server must have the `RELOAD' and `SUPER' privileges on the master and the `SELECT' privilege for the master table to load. On the slave side, the user that issues `LOAD TABLE FROM MASTER' must have privileges for dropping and creating the table. The conditions for `LOAD DATA FROM MASTER' apply here as well. For example, `LOAD TABLE FROM MASTER' works only for `MyISAM' tables. The timeout notes for `LOAD DATA FROM MASTER' apply as well.  File: manual.info, Node: master-pos-wait, Next: reset-slave, Prev: load-table-from-master, Up: replication-slave-sql 13.5.2.4 `MASTER_POS_WAIT()' Syntax ................................... SELECT MASTER_POS_WAIT('MASTER_LOG_FILE', MASTER_LOG_POS [, TIMEOUT]) This is actually a function, not a statement. It is used to ensure that the slave has read and executed events up to a given position in the master's binary log. See *Note miscellaneous-functions::, for a full description.  File: manual.info, Node: reset-slave, Next: set-global-sql-slave-skip-counter, Prev: master-pos-wait, Up: replication-slave-sql 13.5.2.5 `RESET SLAVE' Syntax ............................. RESET SLAVE *Note `RESET SLAVE': reset-slave. makes the slave forget its replication position in the master's binary log. This statement is meant to be used for a clean start: It deletes the `master.info' and `relay-log.info' files, all the relay log files, and starts a new relay log file. To use *Note `RESET SLAVE': reset-slave, the slave replication threads must be stopped (use *Note `STOP SLAVE': stop-slave. if necessary). *Note*: All relay log files are deleted, even if they have not been completely executed by the slave SQL thread. (This is a condition likely to exist on a replication slave if you have issued a *Note `STOP SLAVE': stop-slave. statement or if the slave is highly loaded.) If any startup options for setting connection parameters (such as master host, master port, master user, and master password) are in use, then any corresponding connection information stored in the `master.info' file is immediately reset using the values specified for these options. However, since these options are deprecated in MySQL 5.1 and removed altogether from MySQL 5.5, you are encouraged to use a *Note `CHANGE MASTER TO': change-master-to. statement instead to reset the connection parameters. (If you do not use the startup options, you must issue *Note `CHANGE MASTER TO': change-master-to. in such cases if you do not want the connection settings to be cleared.) If the slave SQL thread was in the middle of replicating temporary tables when it was stopped, and *Note `RESET SLAVE': reset-slave. is issued, these replicated temporary tables are deleted on the slave.  File: manual.info, Node: set-global-sql-slave-skip-counter, Next: start-slave, Prev: reset-slave, Up: replication-slave-sql 13.5.2.6 `SET GLOBAL sql_slave_skip_counter' Syntax ................................................... SET GLOBAL sql_slave_skip_counter = N This statement skips the next N events from the master. This is useful for recovering from replication stops caused by a statement. This statement is valid only when the slave threads are not running. Otherwise, it produces an error. When using this statement, it is important to understand that the binary log is actually organized as a sequence of groups known as _event groups_. Each event group consists of a sequence of events. * For transactional tables, an event group corresponds to a transaction. * For nontransactional tables, an event group corresponds to a single SQL statement. *Note*: A single transaction can contain changes to both transactional and nontransactional tables. When you use *Note `SET GLOBAL sql_slave_skip_counter': set-global-sql-slave-skip-counter. to skip events and the result is in the middle of a group, the slave continues to skip events until it reaches the end of the group. Execution then starts with the next event group. Beginning with MySQL 5.1.47, issuing this statement causes the previous values of `RELAY_LOG_FILE', `RELAY_LOG_POS', and `sql_slave_skip_counter' to be written to the error log.  File: manual.info, Node: start-slave, Next: stop-slave, Prev: set-global-sql-slave-skip-counter, Up: replication-slave-sql 13.5.2.7 `START SLAVE' Syntax ............................. START SLAVE [THREAD_TYPE [, THREAD_TYPE] ... ] START SLAVE [SQL_THREAD] UNTIL MASTER_LOG_FILE = 'LOG_NAME', MASTER_LOG_POS = LOG_POS START SLAVE [SQL_THREAD] UNTIL RELAY_LOG_FILE = 'LOG_NAME', RELAY_LOG_POS = LOG_POS THREAD_TYPE: IO_THREAD | SQL_THREAD *Note `START SLAVE': start-slave. with no THREAD_TYPE options starts both of the slave threads. The I/O thread reads events from the master server and stores them in the relay log. The SQL thread reads events from the relay log and executes them. *Note `START SLAVE': start-slave. requires the `SUPER' privilege. If *Note `START SLAVE': start-slave. succeeds in starting the slave threads, it returns without any error. However, even in that case, it might be that the slave threads start and then later stop (for example, because they do not manage to connect to the master or read its binary log, or some other problem). *Note `START SLAVE': start-slave. does not warn you about this. You must check the slave's error log for error messages generated by the slave threads, or check that they are running satisfactorily with *Note `SHOW SLAVE STATUS': show-slave-status. *Note `START SLAVE': start-slave. sends an acknowledgment to the user after both the I/O thread and the SQL thread have started. However, the I/O thread may not yet have connected. For this reason, a successful *Note `START SLAVE': start-slave. causes *Note `SHOW SLAVE STATUS': show-slave-status. to show `Slave_SQL_Running=Yes', but this does not guarantee that `Slave_IO_Running=Yes' (because `Slave_IO_Running=Yes' only if the I/O thread is running _and connected_). For more information, see *Note show-slave-status::, and *Note replication-administration-status::. You can add `IO_THREAD' and `SQL_THREAD' options to the statement to name which of the threads to start. An `UNTIL' clause may be added to specify that the slave should start and run until the SQL thread reaches a given point in the master binary log or in the slave relay log. When the SQL thread reaches that point, it stops. If the `SQL_THREAD' option is specified in the statement, it starts only the SQL thread. Otherwise, it starts both slave threads. If the SQL thread is running, the `UNTIL' clause is ignored and a warning is issued. For an `UNTIL' clause, you must specify both a log file name and position. Do not mix master and relay log options. Any `UNTIL' condition is reset by a subsequent *Note `STOP SLAVE': stop-slave. statement, a *Note `START SLAVE': start-slave. statement that includes no `UNTIL' clause, or a server restart. The `UNTIL' clause can be useful for debugging replication, or to cause replication to proceed until just before the point where you want to avoid having the slave replicate an event. For example, if an unwise *Note `DROP TABLE': drop-table. statement was executed on the master, you can use `UNTIL' to tell the slave to execute up to that point but no farther. To find what the event is, use *Note `mysqlbinlog': mysqlbinlog. with the master binary log or slave relay log, or by using a *Note `SHOW BINLOG EVENTS': show-binlog-events. statement. If you are using `UNTIL' to have the slave process replicated queries in sections, it is recommended that you start the slave with the `--skip-slave-start' option to prevent the SQL thread from running when the slave server starts. It is probably best to use this option in an option file rather than on the command line, so that an unexpected server restart does not cause it to be forgotten. The *Note `SHOW SLAVE STATUS': show-slave-status. statement includes output fields that display the current values of the `UNTIL' condition. In old versions of MySQL (before 4.0.5), this statement was called `SLAVE START'. This usage is still accepted in MySQL 5.1 for backward compatibility, but is deprecated and is removed in MySQL 5.6.  File: manual.info, Node: stop-slave, Prev: start-slave, Up: replication-slave-sql 13.5.2.8 `STOP SLAVE' Syntax ............................ STOP SLAVE [THREAD_TYPE [, THREAD_TYPE] ... ] THREAD_TYPE: IO_THREAD | SQL_THREAD Stops the slave threads. *Note `STOP SLAVE': stop-slave. requires the `SUPER' privilege. Like *Note `START SLAVE': start-slave, this statement may be used with the `IO_THREAD' and `SQL_THREAD' options to name the thread or threads to be stopped. *Note*: The transactional behavior of *Note `STOP SLAVE': stop-slave. changed in MySQL 5.1.35. Previously, it took effect immediately. Beginning with MySQL 5.1.35, it waits until any current replication event group affecting one or more non-transactional tables has finished executing (if there is any such replication group), or until the user issues a *Note `KILL QUERY': kill. or *Note `KILL CONNECTION': kill. statement. (Bug#319, Bug#38205) In old versions of MySQL (before 4.0.5), this statement was called `SLAVE STOP'. This usage is still accepted in MySQL 5.1 for backward compatibility, but is deprecated and is removed in MySQL 5.6.  File: manual.info, Node: sql-syntax-prepared-statements, Next: sql-syntax-compound-statements, Prev: sql-syntax-replication, Up: sql-syntax 13.6 SQL Syntax for Prepared Statements ======================================= * Menu: * prepare:: `PREPARE' Syntax * execute:: `EXECUTE' Syntax * deallocate-prepare:: `DEALLOCATE PREPARE' Syntax * statement-repreparation:: Automatic Prepared Statement Repreparation MySQL 5.1 provides support for server-side prepared statements. This support takes advantage of the efficient client/server binary protocol implemented in MySQL 4.1, provided that you use an appropriate client programming interface. Candidate interfaces include the MySQL C API client library (for C programs), MySQL Connector/J (for Java programs), and MySQL Connector/NET. For example, the C API provides a set of function calls that make up its prepared statement API. See *Note c-api-prepared-statements::. Other language interfaces can provide support for prepared statements that use the binary protocol by linking in the C client library, one example being the `mysqli' extension (http://php.net/mysqli), available in PHP 5.0 and later. An alternative SQL interface to prepared statements is available. This interface is not as efficient as using the binary protocol through a prepared statement API, but requires no programming because it is available directly at the SQL level: * You can use it when no programming interface is available to you. * You can use it from any program that enables you to send SQL statements to the server to be executed, such as the *Note `mysql': mysql. client program. * You can use it even if the client is using an old version of the client library. The only requirement is that you be able to connect to a server that is recent enough to support SQL syntax for prepared statements. SQL syntax for prepared statements is intended to be used for situations such as these: * You want to test how prepared statements work in your application before coding it. * An application has problems executing prepared statements and you want to determine interactively what the problem is. * You want to create a test case that describes a problem you are having with prepared statements, so that you can file a bug report. * You need to use prepared statements but do not have access to a programming API that supports them. SQL syntax for prepared statements is based on three SQL statements: * *Note `PREPARE': prepare. prepares a statement for execution (see *Note prepare::). * *Note `EXECUTE': execute. executes a prepared statement (see *Note execute::). * *Note `DEALLOCATE PREPARE': deallocate-prepare. releases a prepared statement (see *Note deallocate-prepare::). The following examples show two equivalent ways of preparing a statement that computes the hypotenuse of a triangle given the lengths of the two sides. The first example shows how to create a prepared statement by using a string literal to supply the text of the statement: mysql> PREPARE stmt1 FROM 'SELECT SQRT(POW(?,2) + POW(?,2)) AS hypotenuse'; mysql> SET @a = 3; mysql> SET @b = 4; mysql> EXECUTE stmt1 USING @a, @b; +------------+ | hypotenuse | +------------+ | 5 | +------------+ mysql> DEALLOCATE PREPARE stmt1; The second example is similar, but supplies the text of the statement as a user variable: mysql> SET @s = 'SELECT SQRT(POW(?,2) + POW(?,2)) AS hypotenuse'; mysql> PREPARE stmt2 FROM @s; mysql> SET @a = 6; mysql> SET @b = 8; mysql> EXECUTE stmt2 USING @a, @b; +------------+ | hypotenuse | +------------+ | 10 | +------------+ mysql> DEALLOCATE PREPARE stmt2; Here is an additional example that demonstrates how to choose the table on which to perform a query at runtime, by storing the name of the table as a user variable: mysql> USE test; mysql> CREATE TABLE t1 (a INT NOT NULL); mysql> INSERT INTO t1 VALUES (4), (8), (11), (32), (80); mysql> SET @table = 't1'; mysql> SET @s = CONCAT('SELECT * FROM ', @table); mysql> PREPARE stmt3 FROM @s; mysql> EXECUTE stmt3; +----+ | a | +----+ | 4 | | 8 | | 11 | | 32 | | 80 | +----+ mysql> DEALLOCATE PREPARE stmt3; A prepared statement is specific to the session in which it was created. If you terminate a session without deallocating a previously prepared statement, the server deallocates it automatically. A prepared statement is also global to the session. If you create a prepared statement within a stored routine, it is not deallocated when the stored routine ends. To guard against too many prepared statements being created simultaneously, set the `max_prepared_stmt_count' system variable. To prevent the use of prepared statements, set the value to 0. The following SQL statements can be used in prepared statements: *Note `ALTER TABLE': alter-table, *Note `CALL': call, *Note `COMMIT': commit, *Note `CREATE INDEX': create-index, *Note `CREATE TABLE': create-table, *Note `DELETE': delete, *Note `DO': do, *Note `DROP INDEX': drop-index, *Note `DROP TABLE': drop-table, *Note `INSERT': insert, *Note `RENAME TABLE': rename-table, *Note `REPLACE': replace, *Note `SELECT': select, *Note `SET': set-option, *Note `UPDATE': update, and most *Note `SHOW': show. statements. As of MySQL 5.1.10, the following additional statements are supported: ANALYZE TABLE OPTIMIZE TABLE REPAIR TABLE As of MySQL 5.1.12, the following additional statements are supported: CACHE INDEX CHANGE MASTER CHECKSUM {TABLE | TABLES} {CREATE | DROP} DATABASE {CREATE | RENAME | DROP} USER FLUSH {TABLE | TABLES | TABLES WITH READ LOCK | HOSTS | PRIVILEGES | LOGS | STATUS | MASTER | SLAVE | DES_KEY_FILE | USER_RESOURCES} GRANT REVOKE KILL LOAD INDEX INTO CACHE RESET {MASTER | SLAVE | QUERY CACHE} SHOW BINLOG EVENTS SHOW CREATE {PROCEDURE | FUNCTION | EVENT | TABLE | VIEW} SHOW {AUTHORS | CONTRIBUTORS | WARNINGS | ERRORS} SHOW {MASTER | BINARY} LOGS SHOW {MASTER | SLAVE} STATUS SLAVE {START | STOP} INSTALL PLUGIN UNINSTALL PLUGIN Other statements are not yet supported. Statements not permitted in SQL prepared statements are generally also not permitted in stored routines. Any exceptions to this rule are noted in *Note stored-routines::. Placeholders can be used for the arguments of the `LIMIT' clause when using prepared statements. See *Note select::. In prepared *Note `CALL': call. statements used with *Note `PREPARE': prepare. and *Note `EXECUTE': execute, placeholder support for `OUT' and `INOUT' parameters is not available in MySQL 5.1. See *Note call::, for an example and a workaround. Placeholders can be used for `IN' parameters regardless of version. SQL syntax for prepared statements cannot be used in nested fashion. That is, a statement passed to *Note `PREPARE': prepare. cannot itself be a *Note `PREPARE': prepare, *Note `EXECUTE': execute, or *Note `DEALLOCATE PREPARE': deallocate-prepare. statement. SQL syntax for prepared statements is distinct from using prepared statement API calls. For example, you cannot use the *Note `mysql_stmt_prepare()': mysql-stmt-prepare. C API function to prepare a *Note `PREPARE': prepare, *Note `EXECUTE': execute, or *Note `DEALLOCATE PREPARE': deallocate-prepare. statement. SQL syntax for prepared statements can be used within stored procedures, but not in stored functions or triggers. However, a cursor cannot be used for a dynamic statement that is prepared and executed with *Note `PREPARE': prepare. and *Note `EXECUTE': execute. The statement for a cursor is checked at cursor creation time, so the statement cannot be dynamic. SQL syntax for prepared statements does not support multi-statements (that is, multiple statements within a single string separated by ``;'' characters). Before MySQL 5.1.17, prepared statements do not use the query cache. As of 5.1.17, prepared statements use the query cache under the conditions described in *Note query-cache-operation::. To write C programs that use the *Note `CALL': call. SQL statement to execute stored procedures that contain prepared statements, the `CLIENT_MULTI_RESULTS' flag must be enabled. This is because each *Note `CALL': call. returns a result to indicate the call status, in addition to any result sets that might be returned by statements executed within the procedure. `CLIENT_MULTI_RESULTS' can be enabled when you call *Note `mysql_real_connect()': mysql-real-connect, either explicitly by passing the `CLIENT_MULTI_RESULTS' flag itself, or implicitly by passing `CLIENT_MULTI_STATEMENTS' (which also enables `CLIENT_MULTI_RESULTS'). For additional information, see *Note call::.  File: manual.info, Node: prepare, Next: execute, Prev: sql-syntax-prepared-statements, Up: sql-syntax-prepared-statements 13.6.1 `PREPARE' Syntax ----------------------- PREPARE STMT_NAME FROM PREPARABLE_STMT The *Note `PREPARE': prepare. statement prepares a statement and assigns it a name, STMT_NAME, by which to refer to the statement later. Statement names are not case sensitive. PREPARABLE_STMT is either a string literal or a user variable that contains the text of the statement. The text must represent a single SQL statement, not multiple statements. Within the statement, ``?'' characters can be used as parameter markers to indicate where data values are to be bound to the query later when you execute it. The ``?'' characters should not be enclosed within quotation marks, even if you intend to bind them to string values. Parameter markers can be used only where data values should appear, not for SQL keywords, identifiers, and so forth. If a prepared statement with the given name already exists, it is deallocated implicitly before the new statement is prepared. This means that if the new statement contains an error and cannot be prepared, an error is returned and no statement with the given name exists. A prepared statement is executed with *Note `EXECUTE': execute. and released with *Note `DEALLOCATE PREPARE': deallocate-prepare. The scope of a prepared statement is the session within which it is created. Other sessions cannot see it. For examples, see *Note sql-syntax-prepared-statements::.  File: manual.info, Node: execute, Next: deallocate-prepare, Prev: prepare, Up: sql-syntax-prepared-statements 13.6.2 `EXECUTE' Syntax ----------------------- EXECUTE STMT_NAME [USING @VAR_NAME [, @VAR_NAME] ...] After preparing a statement with *Note `PREPARE': prepare, you execute it with an *Note `EXECUTE': execute. statement that refers to the prepared statement name. If the prepared statement contains any parameter markers, you must supply a `USING' clause that lists user variables containing the values to be bound to the parameters. Parameter values can be supplied only by user variables, and the `USING' clause must name exactly as many variables as the number of parameter markers in the statement. You can execute a given prepared statement multiple times, passing different variables to it or setting the variables to different values before each execution. For examples, see *Note sql-syntax-prepared-statements::.  File: manual.info, Node: deallocate-prepare, Next: statement-repreparation, Prev: execute, Up: sql-syntax-prepared-statements 13.6.3 `DEALLOCATE PREPARE' Syntax ---------------------------------- {DEALLOCATE | DROP} PREPARE STMT_NAME To deallocate a prepared statement produced with *Note `PREPARE': prepare, use a *Note `DEALLOCATE PREPARE': deallocate-prepare. statement that refers to the prepared statement name. Attempting to execute a prepared statement after deallocating it results in an error. For examples, see *Note sql-syntax-prepared-statements::.  File: manual.info, Node: statement-repreparation, Prev: deallocate-prepare, Up: sql-syntax-prepared-statements 13.6.4 Automatic Prepared Statement Repreparation ------------------------------------------------- As of MySQL 5.1.25, metadata changes to tables or views referred to by prepared statements are detected and cause automatic repreparation of the statement when it is next executed. This applies to prepared statements processed at the SQL level (using the *Note `PREPARE': prepare. statement) and those processed using the binary client/server protocol (using the *Note `mysql_stmt_prepare()': mysql-stmt-prepare. C API function). Metadata changes occur for DDL statements such as those that create, drop, alter, rename, or truncate tables, or that analyze, optimize, or repair tables. Repreparation also occurs after referenced tables or views are flushed from the table definition cache, either implicitly to make room for new entries in the cache, or explicitly due to *Note `FLUSH TABLES': flush. Repreparation is automatic, but to the extent that it occurs, performance of prepared statements is diminished. When a statement is reprepared, the default database and SQL mode that were in effect for the original preparation are used. Table content changes (for example, with *Note `INSERT': insert. or *Note `UPDATE': update.) do not cause repreparation, nor do *Note `SELECT': select. statements. An incompatibility with previous versions of MySQL is that a prepared statement may return a different set of columns or different column types from one execution to the next. For example, if the prepared statement is `SELECT * FROM t1', altering `t1' to contain a different number of columns causes the next execution to return a number of columns different from the previous execution. Older versions of the client library cannot handle this change in behavior. For applications that use prepared statements with a server that performs automatic repreparation, an upgrade to the new client library is strongly recommended. The `Com_stmt_reprepare' status variable tracks the number of repreparations. The server attempts repreparation up to three times. An error occurs if all attempts fail.  File: manual.info, Node: sql-syntax-compound-statements, Next: sql-syntax-utility, Prev: sql-syntax-prepared-statements, Up: sql-syntax 13.7 MySQL Compound-Statement Syntax ==================================== * Menu: * begin-end:: `BEGIN ... END' Compound Statement Syntax * declare:: `DECLARE' Syntax * variables-in-stored-programs:: Variables in Stored Programs * conditions-and-handlers:: Conditions and Handlers * cursors:: Cursors * flow-control-constructs:: Flow Control Constructs * return:: `RETURN' Syntax This section describes the syntax for the *Note `BEGIN ... END': begin-end. compound statement and other statements that can be used in the body of stored programs: Stored procedures and functions, triggers, and events. These objects are defined in terms of SQL code that is stored on the server for later invocation (see *Note stored-programs-views::).  File: manual.info, Node: begin-end, Next: declare, Prev: sql-syntax-compound-statements, Up: sql-syntax-compound-statements 13.7.1 `BEGIN ... END' Compound Statement Syntax ------------------------------------------------ [BEGIN_LABEL:] BEGIN [STATEMENT_LIST] END [END_LABEL] *Note `BEGIN ... END': begin-end. syntax is used for writing compound statements, which can appear within stored programs. A compound statement can contain multiple statements, enclosed by the `BEGIN' and `END' keywords. STATEMENT_LIST represents a list of one or more statements, each terminated by a semicolon (`;') statement delimiter. STATEMENT_LIST is optional, which means that the empty compound statement (`BEGIN END') is legal. Use of multiple statements requires that a client is able to send statement strings containing the `;' statement delimiter. This is handled in the *Note `mysql': mysql. command-line client with the `delimiter' command. Changing the `;' end-of-statement delimiter (for example, to `//') permit `;' to be used in a program body. For an example, see *Note stored-programs-defining::. A *Note `BEGIN ... END': begin-end. block can be labeled. Labels follow these rules: * END_LABEL cannot be given unless BEGIN_LABEL is also present. * If both BEGIN_LABEL and END_LABEL are present, they must be the same. * Labels can be up to 16 characters long. Labels are also permitted for the *Note `LOOP': loop-statement, *Note `REPEAT': repeat-statement, and *Note `WHILE': while-statement. statements. The optional `[NOT] ATOMIC' clause is not supported. This means that no transactional savepoint is set at the start of the instruction block and the `BEGIN' clause used in this context has no effect on the current transaction. *Note*: Within all stored programs (stored procedures and functions, triggers, and events), the parser treats *Note `BEGIN [WORK]': commit. as the beginning of a *Note `BEGIN ... END': begin-end. block. Begin a transaction in this context with *Note `START TRANSACTION': commit. instead.  File: manual.info, Node: declare, Next: variables-in-stored-programs, Prev: begin-end, Up: sql-syntax-compound-statements 13.7.2 `DECLARE' Syntax ----------------------- The *Note `DECLARE': declare. statement is used to define various items local to a program: * Local variables. See *Note variables-in-stored-programs::. * Conditions and handlers. See *Note conditions-and-handlers::. * Cursors. See *Note cursors::. The `SIGNAL' and `RESIGNAL' statements are not supported until MySQL 5.5. *Note `DECLARE': declare. is permitted only inside a *Note `BEGIN ... END': begin-end. compound statement and must be at its start, before any other statements. Declarations must follow a certain order. Cursors must be declared before declaring handlers, and variables and conditions must be declared before declaring either cursors or handlers.  File: manual.info, Node: variables-in-stored-programs, Next: conditions-and-handlers, Prev: declare, Up: sql-syntax-compound-statements 13.7.3 Variables in Stored Programs ----------------------------------- * Menu: * declare-local-variable:: `DECLARE' for Local Variables * set-statement:: Variable `SET' Statement * select-into-statement:: `SELECT ... INTO' Statement * local-variable-scope:: Scope and Resolution of Local Variables You may declare and use variables within stored programs.  File: manual.info, Node: declare-local-variable, Next: set-statement, Prev: variables-in-stored-programs, Up: variables-in-stored-programs 13.7.3.1 `DECLARE' for Local Variables ...................................... DECLARE VAR_NAME [, VAR_NAME] ... TYPE [DEFAULT VALUE] This statement is used to declare local variables within stored programs. To provide a default value for the variable, include a `DEFAULT' clause. The value can be specified as an expression; it need not be a constant. If the `DEFAULT' clause is missing, the initial value is `NULL'. Local variables are treated like stored routine parameters with respect to data type and overflow checking. See *Note create-procedure::. Local variable names are not case sensitive. Permissible characters and quoting rules are the same as for other identifiers, as described in *Note identifiers::. The scope of a local variable is within the *Note `BEGIN ... END': begin-end. block where it is declared. The variable can be referred to in blocks nested within the declaring block, except those blocks that declare a variable with the same name.  File: manual.info, Node: set-statement, Next: select-into-statement, Prev: declare-local-variable, Up: variables-in-stored-programs 13.7.3.2 Variable `SET' Statement ................................. SET VAR_NAME = EXPR [, VAR_NAME = EXPR] ... The `SET' statement in stored programs is an extended version of the general *Note `SET': set-option. statement (see *Note set-option::). Each VAR_NAME may refer to a local variable declared inside a stored program, a system variable, or a user-defined variable. The `SET' statement in stored programs is implemented as part of the pre-existing *Note `SET': set-option. syntax. This enables an extended syntax of `SET a=x, b=y, ...' where different variable types (locally declared variables, global and session system variables, user-defined variables) can be mixed. This also enables combinations of local variables and some options that make sense only for system variables; in that case, the options are recognized but ignored.  File: manual.info, Node: select-into-statement, Next: local-variable-scope, Prev: set-statement, Up: variables-in-stored-programs 13.7.3.3 `SELECT ... INTO' Statement .................................... SELECT COL_NAME [, COL_NAME] ... INTO VAR_NAME [, VAR_NAME] ... TABLE_EXPR *Note `SELECT ... INTO': select. syntax enables selected columns to be stored directly into variables. The query should return a single row. If the query returns no rows, a warning with error code 1329 occurs (`No data'), and the variable values remain unchanged. If the query returns multiple rows, error 1172 occurs (`Result consisted of more than one row'). If it is possible that the statement may retrieve multiple rows, you can use `LIMIT 1' to limit the result set to a single row. SELECT id,data INTO x,y FROM test.t1 LIMIT 1; User variable names are not case sensitive. See *Note user-variables::. In the context of *Note `SELECT ... INTO': select. statements that occur as part of events executed by the Event Scheduler, diagnostics messages (not only errors, but also warnings) are written to the error log, and, on Windows, to the application event log. For additional information, see *Note events-status-info::.  File: manual.info, Node: local-variable-scope, Prev: select-into-statement, Up: variables-in-stored-programs 13.7.3.4 Scope and Resolution of Local Variables ................................................ The scope of a local variable is within the *Note `BEGIN ... END': begin-end. block where it is declared. The variable can be referred to in blocks nested within the declaring block, except those blocks that declare a variable with the same name. Local variables are within scope only during stored routine execution, so references to them are not permitted within prepared statements because those are global to the current session and the variables might have gone out of scope when the statement is executed. For example, `SELECT ... INTO LOCAL_VAR' cannot be used as a prepared statement. Local variable names should not be the same as column names. If an SQL statement, such as a *Note `SELECT ... INTO': select. statement, contains a reference to a column and a declared local variable with the same name, MySQL currently interprets the reference as the name of a variable. Consider the following procedure definition: CREATE PROCEDURE sp1 (x VARCHAR(5)) BEGIN DECLARE xname VARCHAR(5) DEFAULT 'bob'; DECLARE newname VARCHAR(5); DECLARE xid INT; SELECT xname, id INTO newname, xid FROM table1 WHERE xname = xname; SELECT newname; END; MySQL interprets `xname' in the *Note `SELECT': select. statement as a reference to the `xname' _variable_ rather than the `xname' _column_. Consequently, when the procedure `sp1()'is called, the `newname' variable returns the value `'bob'' regardless of the value of the `table1.xname' column. Similarly, the cursor definition in the following procedure contains a *Note `SELECT': select. statement that refers to `xname'. MySQL interprets this as a reference to the variable of that name rather than a column reference. CREATE PROCEDURE sp2 (x VARCHAR(5)) BEGIN DECLARE xname VARCHAR(5) DEFAULT 'bob'; DECLARE newname VARCHAR(5); DECLARE xid INT; DECLARE done TINYINT DEFAULT 0; DECLARE cur1 CURSOR FOR SELECT xname, id FROM table1; DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = 1; OPEN cur1; read_loop: LOOP FETCH FROM cur1 INTO newname, xid; IF done THEN LEAVE read_loop; END IF; SELECT newname; END LOOP; CLOSE cur1; END; See also *Note stored-program-restrictions::.  File: manual.info, Node: conditions-and-handlers, Next: cursors, Prev: variables-in-stored-programs, Up: sql-syntax-compound-statements 13.7.4 Conditions and Handlers ------------------------------ * Menu: * declare-condition:: `DECLARE' for Conditions * declare-handler:: `DECLARE' for Handlers Certain conditions may require specific handling. These conditions can relate to errors or warnings, as well as to general flow control inside a stored program.  File: manual.info, Node: declare-condition, Next: declare-handler, Prev: conditions-and-handlers, Up: conditions-and-handlers 13.7.4.1 `DECLARE' for Conditions ................................. DECLARE CONDITION_NAME CONDITION FOR CONDITION_VALUE CONDITION_VALUE: SQLSTATE [VALUE] SQLSTATE_VALUE | MYSQL_ERROR_CODE The `DECLARE ... CONDITION' statement defines a named error condition. It specifies a condition that needs specific handling and associates a name with that condition. The name can be referred to in a subsequent `DECLARE ... HANDLER' statement. For an example, see *Note declare-handler::. A CONDITION_VALUE for `DECLARE ... CONDITION' can be an SQLSTATE value (a 5-character string literal) or a MySQL error code (a number). You should not use SQLSTATE value `'00000'' or MySQL error code 0, because those indicate success rather than an error condition. For a list of SQLSTATE values and MySQL error codes, see *Note error-messages-server::.  File: manual.info, Node: declare-handler, Prev: declare-condition, Up: conditions-and-handlers 13.7.4.2 `DECLARE' for Handlers ............................... DECLARE HANDLER_TYPE HANDLER FOR CONDITION_VALUE [, CONDITION_VALUE] ... STATEMENT HANDLER_TYPE: CONTINUE | EXIT | UNDO CONDITION_VALUE: SQLSTATE [VALUE] SQLSTATE_VALUE | CONDITION_NAME | SQLWARNING | NOT FOUND | SQLEXCEPTION | MYSQL_ERROR_CODE The `DECLARE ... HANDLER' statement specifies handlers that each may deal with one or more conditions. If one of these conditions occurs, the specified STATEMENT is executed. STATEMENT can be a simple statement (for example, `SET VAR_NAME = VALUE'), or it can be a compound statement written using `BEGIN' and `END' (see *Note begin-end::). For a `CONTINUE' handler, execution of the current program continues after execution of the handler statement. For an `EXIT' handler, execution terminates for the *Note `BEGIN ... END': begin-end. compound statement in which the handler is declared. (This is true even if the condition occurs in an inner block.) The `UNDO' handler type statement is not supported. If a condition occurs for which no handler has been declared, the default action is `EXIT'. A CONDITION_VALUE for `DECLARE ... HANDLER' can be any of the following values: * An SQLSTATE value (a 5-character string literal) or a MySQL error code (a number). You should not use SQLSTATE value `'00000'' or MySQL error code 0, because those indicate success rather than an error condition. For a list of SQLSTATE values and MySQL error codes, see *Note error-messages-server::. * A condition name previously specified with `DECLARE ... CONDITION'. See *Note declare-condition::. * `SQLWARNING' is shorthand for the class of SQLSTATE values that begin with `'01''. * `NOT FOUND' is shorthand for the class of SQLSTATE values that begin with `'02''. This is relevant only within the context of cursors and is used to control what happens when a cursor reaches the end of a data set. If no more rows are available, a No Data condition occurs with SQLSTATE value 02000. To detect this condition, you can set up a handler for it (or for a `NOT FOUND' condition). An example is shown in *Note cursors::. This condition also occurs for `SELECT ... INTO VAR_LIST' statements that retrieve no rows. * `SQLEXCEPTION' is shorthand for the class of SQLSTATE values that do not begin with `'00'', `'01'', or `'02''. Example: mysql> CREATE TABLE test.t (s1 INT, PRIMARY KEY (s1)); Query OK, 0 rows affected (0.00 sec) mysql> delimiter // mysql> CREATE PROCEDURE handlerdemo () -> BEGIN -> DECLARE CONTINUE HANDLER FOR SQLSTATE '23000' SET @x2 = 1; -> SET @x = 1; -> INSERT INTO test.t VALUES (1); -> SET @x = 2; -> INSERT INTO test.t VALUES (1); -> SET @x = 3; -> END; -> // Query OK, 0 rows affected (0.00 sec) mysql> CALL handlerdemo()// Query OK, 0 rows affected (0.00 sec) mysql> SELECT @x// +------+ | @x | +------+ | 3 | +------+ 1 row in set (0.00 sec) The example associates a handler with SQLSTATE value `'23000'', which occurs for a duplicate-key error. Notice that `@x' is `3' after the procedure executes, which shows that execution continued to the end of the procedure. If the `DECLARE ... HANDLER' statement had not been present, MySQL would have taken the default path (`EXIT') after the second *Note `INSERT': insert. failed due to the `PRIMARY KEY' constraint, and `SELECT @x' would have returned `2'. If you want to ignore a condition, you can declare a `CONTINUE' handler for it and associate it with an empty block. For example: DECLARE CONTINUE HANDLER FOR SQLWARNING BEGIN END; The statement associated with a handler cannot use *Note `ITERATE': iterate-statement. or *Note `LEAVE': leave-statement. to refer to labels for blocks that enclose the handler declaration. That is, the scope of a block label does not include the code for handlers declared within the block. Consider the following example, where the *Note `REPEAT': repeat-statement. block has a label of `retry': CREATE PROCEDURE p () BEGIN DECLARE i INT DEFAULT 3; retry: REPEAT BEGIN DECLARE CONTINUE HANDLER FOR SQLWARNING BEGIN ITERATE retry; # illegal END; END; IF i < 0 THEN LEAVE retry; # legal END IF; SET i = i - 1; UNTIL FALSE END REPEAT; END; The label is in scope for the *Note `IF': if-statement. statement within the block. It is not in scope for the `CONTINUE' handler, so the reference there is invalid and results in an error: ERROR 1308 (42000): LEAVE with no matching label: retry To avoid using references to outer labels in handlers, you can use these strategies: * To leave the block, use an `EXIT' handler: DECLARE EXIT HANDLER FOR SQLWARNING BEGIN END; * To iterate, set a status variable in the handler that can be checked in the enclosing block to determine whether the handler was invoked. The following example uses the variable `done' for this purpose: CREATE PROCEDURE p () BEGIN DECLARE i INT DEFAULT 3; DECLARE done INT DEFAULT FALSE; retry: REPEAT BEGIN DECLARE CONTINUE HANDLER FOR SQLWARNING BEGIN SET done = TRUE; END; END; IF NOT done AND i < 0 THEN LEAVE retry; END IF; SET i = i - 1; UNTIL FALSE END REPEAT; END;  File: manual.info, Node: cursors, Next: flow-control-constructs, Prev: conditions-and-handlers, Up: sql-syntax-compound-statements 13.7.5 Cursors -------------- * Menu: * declare-cursor:: `DECLARE' for Cursors * open:: Cursor `OPEN' Statement * fetch:: Cursor `FETCH' Statement * close:: Cursor `CLOSE' Statement Cursors are supported inside stored routines, triggers, and events. The syntax is as in embedded SQL. Cursors in MySQL have these properties: * Asensitive: The server may or may not make a copy of its result table * Read only: Not updatable * Nonscrollable: Can be traversed only in one direction and cannot skip rows Cursors must be declared before declaring handlers. Variables and conditions must be declared before declaring either cursors or handlers. Variables should not have the same names as columns for reasons described in *Note local-variable-scope::. Example: CREATE PROCEDURE curdemo() BEGIN DECLARE done INT DEFAULT 0; DECLARE a CHAR(16); DECLARE b,c INT; DECLARE cur1 CURSOR FOR SELECT id,data FROM test.t1; DECLARE cur2 CURSOR FOR SELECT i FROM test.t2; DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = 1; OPEN cur1; OPEN cur2; read_loop: LOOP FETCH cur1 INTO a, b; FETCH cur2 INTO c; IF done THEN LEAVE read_loop; END IF; IF b < c THEN INSERT INTO test.t3 VALUES (a,b); ELSE INSERT INTO test.t3 VALUES (a,c); END IF; END LOOP; CLOSE cur1; CLOSE cur2; END;  File: manual.info, Node: declare-cursor, Next: open, Prev: cursors, Up: cursors 13.7.5.1 `DECLARE' for Cursors .............................. DECLARE CURSOR_NAME CURSOR FOR SELECT_STATEMENT This statement declares a cursor. Multiple cursors may be declared in a stored program, but each cursor in a given block must have a unique name. The *Note `SELECT': select. statement cannot have an `INTO' clause. Local variables should not be declared with the same name as columns referenced by the *Note `SELECT': select. statement, for reasons described in *Note local-variable-scope::. For information available through *Note `SHOW': show. statements, it is possible in many cases to obtain equivalent information by using a cursor with an `INFORMATION_SCHEMA' table.  File: manual.info, Node: open, Next: fetch, Prev: declare-cursor, Up: cursors 13.7.5.2 Cursor `OPEN' Statement ................................ OPEN CURSOR_NAME This statement opens a previously declared cursor.  File: manual.info, Node: fetch, Next: close, Prev: open, Up: cursors 13.7.5.3 Cursor `FETCH' Statement ................................. FETCH CURSOR_NAME INTO VAR_NAME [, VAR_NAME] ... This statement fetches the next row (if a row exists) using the specified open cursor, and advances the cursor pointer. If no more rows are available, a No Data condition occurs with SQLSTATE value 02000. To detect this condition, you can set up a handler for it (or for a `NOT FOUND' condition). An example is shown in *Note cursors::.  File: manual.info, Node: close, Prev: fetch, Up: cursors 13.7.5.4 Cursor `CLOSE' Statement ................................. CLOSE CURSOR_NAME This statement closes a previously opened cursor. If not closed explicitly, a cursor is closed at the end of the compound statement in which it was declared.  File: manual.info, Node: flow-control-constructs, Next: return, Prev: cursors, Up: sql-syntax-compound-statements 13.7.6 Flow Control Constructs ------------------------------ * Menu: * if-statement:: `IF' Statement * case-statement:: `CASE' Statement * loop-statement:: `LOOP' Statement * leave-statement:: `LEAVE' Statement * iterate-statement:: `ITERATE' Statement * repeat-statement:: `REPEAT' Statement * while-statement:: `WHILE' Statement MySQL supports the *Note `IF': if-statement, *Note `CASE': case-statement, *Note `ITERATE': iterate-statement, *Note `LEAVE': leave-statement. *Note `LOOP': loop-statement, *Note `WHILE': while-statement, and *Note `REPEAT': repeat-statement. constructs for flow control within stored programs. Many of these constructs contain other statements, as indicated by the grammar specifications in the following sections. Such constructs may be nested. For example, an *Note `IF': if-statement. statement might contain a *Note `WHILE': while-statement. loop, which itself contains a *Note `CASE': case-statement. statement. `FOR' loops are not supported.  File: manual.info, Node: if-statement, Next: case-statement, Prev: flow-control-constructs, Up: flow-control-constructs 13.7.6.1 `IF' Statement ....................... IF SEARCH_CONDITION THEN STATEMENT_LIST [ELSEIF SEARCH_CONDITION THEN STATEMENT_LIST] ... [ELSE STATEMENT_LIST] END IF *Note `IF': if-statement. implements a basic conditional construct. If the SEARCH_CONDITION evaluates to true, the corresponding SQL statement list is executed. If no SEARCH_CONDITION matches, the statement list in the `ELSE' clause is executed. Each STATEMENT_LIST consists of one or more statements. *Note*: There is also an `IF()' _function_, which differs from the *Note `IF': if-statement. _statement_ described here. See *Note control-flow-functions::. An `IF ... END IF' block, like all other flow-control blocks used within stored programs, must be terminated with a semicolon, as shown in this example: DELIMITER // CREATE FUNCTION SimpleCompare(n INT, m INT) RETURNS VARCHAR(20) BEGIN DECLARE s VARCHAR(20); IF n > m THEN SET s = '>'; ELSEIF n = m THEN SET s = '='; ELSE SET s = '<'; END IF; SET s = CONCAT(n, ' ', s, ' ', m); RETURN s; END // DELIMITER ; As with other flow-control constructs, `IF ... END IF' blocks may be nested within other flow-control constructs, including other *Note `IF': if-statement. statements. Each *Note `IF': if-statement. must be terminated by its own `END IF' followed by a semicolon. You can use indentation to make nested flow-control blocks more easily readable by humans (although this is not required by MySQL), as shown here: DELIMITER // CREATE FUNCTION VerboseCompare (n INT, m INT) RETURNS VARCHAR(50) BEGIN DECLARE s VARCHAR(50); IF n = m THEN SET s = 'equals'; ELSE IF n > m THEN SET s = 'greater'; ELSE SET s = 'less'; END IF; SET s = CONCAT('is ', s, ' than'); END IF; SET s = CONCAT(n, ' ', s, ' ', m, '.'); RETURN s; END // DELIMITER ; In this example, the inner *Note `IF': if-statement. is evaluated only if `n' is not equal to `m'.  File: manual.info, Node: case-statement, Next: loop-statement, Prev: if-statement, Up: flow-control-constructs 13.7.6.2 `CASE' Statement ......................... CASE CASE_VALUE WHEN WHEN_VALUE THEN STATEMENT_LIST [WHEN WHEN_VALUE THEN STATEMENT_LIST] ... [ELSE STATEMENT_LIST] END CASE Or: CASE WHEN SEARCH_CONDITION THEN STATEMENT_LIST [WHEN SEARCH_CONDITION THEN STATEMENT_LIST] ... [ELSE STATEMENT_LIST] END CASE The *Note `CASE': case-statement. statement for stored programs implements a complex conditional construct. If a SEARCH_CONDITION evaluates to true, the corresponding SQL statement list is executed. If no search condition matches, the statement list in the `ELSE' clause is executed. Each STATEMENT_LIST consists of one or more statements. If no WHEN_VALUE or SEARCH_CONDITION matches the value tested and the *Note `CASE': case-statement. statement contains no `ELSE' clause, a `Case not found for CASE statement' error results. Each STATEMENT_LIST consists of one or more statements; an empty STATEMENT_LIST is not permitted. To handle situations where no value is matched by any `WHEN' clause, use an `ELSE' containing an empty *Note `BEGIN ... END': begin-end. block, as shown in this example: DELIMITER | CREATE PROCEDURE p() BEGIN DECLARE v INT DEFAULT 1; CASE v WHEN 2 THEN SELECT v; WHEN 3 THEN SELECT 0; ELSE BEGIN END; END CASE; END; | (The indentation used here in the `ELSE' clause is for purposes of clarity only, and is not otherwise significant.) *Note*: The syntax of the *Note `CASE': case-statement. _statement_ used inside stored programs differs slightly from that of the SQL `CASE' _expression_ described in *Note control-flow-functions::. The *Note `CASE': case-statement. statement cannot have an `ELSE NULL' clause, and it is terminated with `END CASE' instead of `END'.  File: manual.info, Node: loop-statement, Next: leave-statement, Prev: case-statement, Up: flow-control-constructs 13.7.6.3 `LOOP' Statement ......................... [BEGIN_LABEL:] LOOP STATEMENT_LIST END LOOP [END_LABEL] *Note `LOOP': loop-statement. implements a simple loop construct, enabling repeated execution of the statement list, which consists of one or more statements, each terminated by a semicolon (`;') statement delimiter. The statements within the loop are repeated until the loop is exited; usually this is accomplished with a *Note `LEAVE': leave-statement. statement. A *Note `LOOP': loop-statement. statement can be labeled. See *Note begin-end:: for the rules regarding label use.  File: manual.info, Node: leave-statement, Next: iterate-statement, Prev: loop-statement, Up: flow-control-constructs 13.7.6.4 `LEAVE' Statement .......................... LEAVE LABEL This statement is used to exit the flow control construct that has the given label. It can be used within *Note `BEGIN ... END': begin-end. or loop constructs (*Note `LOOP': loop-statement, *Note `REPEAT': repeat-statement, *Note `WHILE': while-statement.).  File: manual.info, Node: iterate-statement, Next: repeat-statement, Prev: leave-statement, Up: flow-control-constructs 13.7.6.5 `ITERATE' Statement ............................ ITERATE LABEL *Note `ITERATE': iterate-statement. can appear only within *Note `LOOP': loop-statement, *Note `REPEAT': repeat-statement, and *Note `WHILE': while-statement. statements. *Note `ITERATE': iterate-statement. means `do the loop again.' Example: CREATE PROCEDURE doiterate(p1 INT) BEGIN label1: LOOP SET p1 = p1 + 1; IF p1 < 10 THEN ITERATE label1; END IF; LEAVE label1; END LOOP label1; SET @x = p1; END;  File: manual.info, Node: repeat-statement, Next: while-statement, Prev: iterate-statement, Up: flow-control-constructs 13.7.6.6 `REPEAT' Statement ........................... [BEGIN_LABEL:] REPEAT STATEMENT_LIST UNTIL SEARCH_CONDITION END REPEAT [END_LABEL] The statement list within a *Note `REPEAT': repeat-statement. statement is repeated until the SEARCH_CONDITION is true. Thus, a *Note `REPEAT': repeat-statement. always enters the loop at least once. STATEMENT_LIST consists of one or more statements, each terminated by a semicolon (`;') statement delimiter. A *Note `REPEAT': repeat-statement. statement can be labeled. See *Note begin-end:: for the rules regarding label use. Example: mysql> delimiter // mysql> CREATE PROCEDURE dorepeat(p1 INT) -> BEGIN -> SET @x = 0; -> REPEAT SET @x = @x + 1; UNTIL @x > p1 END REPEAT; -> END -> // Query OK, 0 rows affected (0.00 sec) mysql> CALL dorepeat(1000)// Query OK, 0 rows affected (0.00 sec) mysql> SELECT @x// +------+ | @x | +------+ | 1001 | +------+ 1 row in set (0.00 sec)  File: manual.info, Node: while-statement, Prev: repeat-statement, Up: flow-control-constructs 13.7.6.7 `WHILE' Statement .......................... [BEGIN_LABEL:] WHILE SEARCH_CONDITION DO STATEMENT_LIST END WHILE [END_LABEL] The statement list within a *Note `WHILE': while-statement. statement is repeated as long as the SEARCH_CONDITION is true. STATEMENT_LIST consists of one or more statements. A *Note `WHILE': while-statement. statement can be labeled. See *Note begin-end:: for the rules regarding label use. Example: CREATE PROCEDURE dowhile() BEGIN DECLARE v1 INT DEFAULT 5; WHILE v1 > 0 DO ... SET v1 = v1 - 1; END WHILE; END;  File: manual.info, Node: return, Prev: flow-control-constructs, Up: sql-syntax-compound-statements 13.7.7 `RETURN' Syntax ---------------------- RETURN EXPR The *Note `RETURN': return. statement terminates execution of a stored function and returns the value EXPR to the function caller. There must be at least one *Note `RETURN': return. statement in a stored function. There may be more than one if the function has multiple exit points. This statement is not used in stored procedures, triggers, or events.  File: manual.info, Node: sql-syntax-utility, Prev: sql-syntax-compound-statements, Up: sql-syntax 13.8 MySQL Utility Statements ============================= * Menu: * describe:: `DESCRIBE' Syntax * explain:: `EXPLAIN' Syntax * help:: `HELP' Syntax * use:: `USE' Syntax  File: manual.info, Node: describe, Next: explain, Prev: sql-syntax-utility, Up: sql-syntax-utility 13.8.1 `DESCRIBE' Syntax ------------------------ {DESCRIBE | DESC} TBL_NAME [COL_NAME | WILD] *Note `DESCRIBE': describe. provides information about the columns in a table. It is a shortcut for `SHOW COLUMNS FROM'. These statements also display information for views. (See *Note show-columns::.) COL_NAME can be a column name, or a string containing the SQL ``%'' and ``_'' wildcard characters to obtain output only for the columns with names matching the string. There is no need to enclose the string within quotation marks unless it contains spaces or other special characters. mysql> DESCRIBE City; +------------+----------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +------------+----------+------+-----+---------+----------------+ | Id | int(11) | NO | PRI | NULL | auto_increment | | Name | char(35) | NO | | | | | Country | char(3) | NO | UNI | | | | District | char(20) | YES | MUL | | | | Population | int(11) | NO | | 0 | | +------------+----------+------+-----+---------+----------------+ 5 rows in set (0.00 sec) The description for *Note `SHOW COLUMNS': show-columns. provides more information about the output columns (see *Note show-columns::). If the data types differ from what you expect them to be based on a *Note `CREATE TABLE': create-table. statement, note that MySQL sometimes changes data types when you create or alter a table. The conditions under which this occurs are described in *Note silent-column-changes::. The *Note `DESCRIBE': describe. statement is provided for compatibility with Oracle. The *Note `SHOW CREATE TABLE': show-create-table, *Note `SHOW TABLE STATUS': show-table-status, and *Note `SHOW INDEX': show-index. statements also provide information about tables. See *Note show::.  File: manual.info, Node: explain, Next: help, Prev: describe, Up: sql-syntax-utility 13.8.2 `EXPLAIN' Syntax ----------------------- EXPLAIN [EXTENDED | PARTITIONS] SELECT SELECT_OPTIONS Or: EXPLAIN TBL_NAME The *Note `EXPLAIN': explain. statement can be used either as a way to obtain information about how MySQL executes a *Note `SELECT': select. statement or as a synonym for *Note `DESCRIBE': describe.: * When you precede a *Note `SELECT': select. statement with the keyword *Note `EXPLAIN': explain, MySQL displays information from the optimizer about the query execution plan. That is, MySQL explains how it would process the *Note `SELECT': select, including information about how tables are joined and in which order. *Note `EXPLAIN EXTENDED': explain. can be used to provide additional information. For information on how to use *Note `EXPLAIN': explain. and *Note `EXPLAIN EXTENDED': explain. to obtain query execution plan information, see *Note using-explain::. * *Note `EXPLAIN PARTITIONS': explain. is available beginning with MySQL 5.1.5. It is useful only when examining queries involving partitioned tables. For details, see *Note partitioning-info::. * *Note `EXPLAIN TBL_NAME': explain. is synonymous with `DESCRIBE TBL_NAME' or `SHOW COLUMNS FROM TBL_NAME'. For a description of the *Note `DESCRIBE': describe. and *Note `SHOW COLUMNS': show-columns. statements, see *Note describe::, and *Note show-columns::.  File: manual.info, Node: help, Next: use, Prev: explain, Up: sql-syntax-utility 13.8.3 `HELP' Syntax -------------------- HELP 'SEARCH_STRING' The *Note `HELP': help. statement returns online information from the MySQL Reference manual. Its proper operation requires that the help tables in the `mysql' database be initialized with help topic information (see *Note server-side-help-support::). The *Note `HELP': help. statement searches the help tables for the given search string and displays the result of the search. The search string is not case sensitive. The HELP statement understands several types of search strings: * At the most general level, use `contents' to retrieve a list of the top-level help categories: HELP 'contents' * For a list of topics in a given help category, such as `Data Types', use the category name: HELP 'data types' * For help on a specific help topic, such as the `ASCII()' function or the *Note `CREATE TABLE': create-table. statement, use the associated keyword or keywords: HELP 'ascii' HELP 'create table' In other words, the search string matches a category, many topics, or a single topic. You cannot necessarily tell in advance whether a given search string will return a list of items or the help information for a single help topic. However, you can tell what kind of response *Note `HELP': help. returned by examining the number of rows and columns in the result set. The following descriptions indicate the forms that the result set can take. Output for the example statements is shown using the familiar `tabular' or `vertical' format that you see when using the *Note `mysql': mysql. client, but note that *Note `mysql': mysql. itself reformats *Note `HELP': help. result sets in a different way. * Empty result set No match could be found for the search string. * Result set containing a single row with three columns This means that the search string yielded a hit for the help topic. The result has three columns: * `name': The topic name. * `description': Descriptive help text for the topic. * `example': Usage example or examples. This column might be blank. Example: `HELP 'replace'' Yields: name: REPLACE description: Syntax: REPLACE(str,from_str,to_str) Returns the string str with all occurrences of the string from_str replaced by the string to_str. REPLACE() performs a case-sensitive match when searching for from_str. example: mysql> SELECT REPLACE('www.mysql.com', 'w', 'Ww'); -> 'WwWwWw.mysql.com' * Result set containing multiple rows with two columns This means that the search string matched many help topics. The result set indicates the help topic names: * `name': The help topic name. * `is_it_category': `Y' if the name represents a help category, `N' if it does not. If it does not, the `name' value when specified as the argument to the *Note `HELP': help. statement should yield a single-row result set containing a description for the named item. Example: `HELP 'status'' Yields: +-----------------------+----------------+ | name | is_it_category | +-----------------------+----------------+ | SHOW | N | | SHOW ENGINE | N | | SHOW INNODB STATUS | N | | SHOW MASTER STATUS | N | | SHOW PROCEDURE STATUS | N | | SHOW SLAVE STATUS | N | | SHOW STATUS | N | | SHOW TABLE STATUS | N | +-----------------------+----------------+ * Result set containing multiple rows with three columns This means the search string matches a category. The result set contains category entries: * `source_category_name': The help category name. * `name': The category or topic name * `is_it_category': `Y' if the name represents a help category, `N' if it does not. If it does not, the `name' value when specified as the argument to the *Note `HELP': help. statement should yield a single-row result set containing a description for the named item. Example: `HELP 'functions'' Yields: +----------------------+-------------------------+----------------+ | source_category_name | name | is_it_category | +----------------------+-------------------------+----------------+ | Functions | CREATE FUNCTION | N | | Functions | DROP FUNCTION | N | | Functions | Bit Functions | Y | | Functions | Comparison operators | Y | | Functions | Control flow functions | Y | | Functions | Date and Time Functions | Y | | Functions | Encryption Functions | Y | | Functions | Information Functions | Y | | Functions | Logical operators | Y | | Functions | Miscellaneous Functions | Y | | Functions | Numeric Functions | Y | | Functions | String Functions | Y | +----------------------+-------------------------+----------------+ Before MySQL 5.1.17, if you intend to use the *Note `HELP': help. statement while other tables are locked with *Note `LOCK TABLES': lock-tables, you must also lock the required `mysql.help_XXX' tables. See *Note lock-tables::.  File: manual.info, Node: use, Prev: help, Up: sql-syntax-utility 13.8.4 `USE' Syntax ------------------- USE DB_NAME The `USE DB_NAME' statement tells MySQL to use the DB_NAME database as the default (current) database for subsequent statements. The database remains the default until the end of the session or another *Note `USE': use. statement is issued: USE db1; SELECT COUNT(*) FROM mytable; # selects from db1.mytable USE db2; SELECT COUNT(*) FROM mytable; # selects from db2.mytable Making a particular database the default by means of the *Note `USE': use. statement does not preclude you from accessing tables in other databases. The following example accesses the `author' table from the `db1' database and the `editor' table from the `db2' database: USE db1; SELECT author_name,editor_name FROM author,db2.editor WHERE author.editor_id = db2.editor.editor_id; The *Note `USE': use. statement is provided for compatibility with Sybase.  File: manual.info, Node: storage-engines, Next: ha-overview, Prev: sql-syntax, Up: Top 14 Storage Engines ****************** * Menu: * storage-engine-compare-transactions:: Comparing Transaction and Nontransaction Engines * storage-engines-other:: Other Storage Engines * storage-engine-setting:: Setting the Storage Engine * pluggable-storage-overview:: Overview of MySQL Storage Engine Architecture * myisam-storage-engine:: The `MyISAM' Storage Engine * innodb-storage-engine:: The `InnoDB' Storage Engine * se-db2:: The `IBMDB2I' Storage Engine * merge-storage-engine:: The `MERGE' Storage Engine * memory-storage-engine:: The `MEMORY' Storage Engine * example-storage-engine:: The `EXAMPLE' Storage Engine * federated-storage-engine:: The `FEDERATED' Storage Engine * archive-storage-engine:: The `ARCHIVE' Storage Engine * csv-storage-engine:: The `CSV' Storage Engine * blackhole-storage-engine:: The `BLACKHOLE' Storage Engine MySQL supports several storage engines that act as handlers for different table types. MySQL storage engines include both those that handle transaction-safe tables and those that handle nontransaction-safe tables. As of MySQL 5.1, MySQL Server uses a pluggable storage engine architecture that enables storage engines to be loaded into and unloaded from a running MySQL server. *Note*: Prior to MySQL 5.1.38, the pluggable storage engine architecture is supported on Unix platforms only and pluggable storage engines are not supported on Windows. To determine which storage engines your server supports by using the *Note `SHOW ENGINES': show-engines. statement. The value in the `Support' column indicates whether an engine can be used. A value of `YES', `NO', or `DEFAULT' indicates that an engine is available, not available, or available and currently set as the default storage engine. mysql> SHOW ENGINES\G *************************** 1. row *************************** Engine: FEDERATED Support: NO Comment: Federated MySQL storage engine Transactions: NULL XA: NULL Savepoints: NULL *************************** 2. row *************************** Engine: MRG_MYISAM Support: YES Comment: Collection of identical MyISAM tables Transactions: NO XA: NO Savepoints: NO *************************** 3. row *************************** Engine: MyISAM Support: DEFAULT Comment: Default engine as of MySQL 3.23 with great performance Transactions: NO XA: NO Savepoints: NO ... This chapter describes each of the MySQL storage engines except for *Note `NDBCLUSTER': mysql-cluster, which is covered in *Note mysql-cluster::. It also contains a description of the pluggable storage engine architecture (see *Note pluggable-storage-overview::). For information about storage engine support offered in commercial MySQL Server binaries, see `MySQL Enterprise Server 5.1' (http://www.mysql.com/products/enterprise/server.html), on the MySQL Web site. The storage engines available might depend on which edition of Enterprise Server you are using. For answers to some commonly asked questions about MySQL storage engines, see *Note faqs-storage-engines::. *MySQL 5.1 supported storage engines* * *Note `MyISAM': myisam-storage-engine.: The default MySQL storage engine and the one that is used the most in Web, data warehousing, and other application environments. `MyISAM' is supported in all MySQL configurations, and is the default storage engine unless you have configured MySQL to use a different one by default. * *Note `InnoDB': innodb-storage-engine.: A transaction-safe (ACID compliant) storage engine for MySQL that has commit, rollback, and crash-recovery capabilities to protect user data. `InnoDB' row-level locking (without escalation to coarser granularity locks) and Oracle-style consistent nonlocking reads increase multi-user concurrency and performance. `InnoDB' stores user data in clustered indexes to reduce I/O for common queries based on primary keys. To maintain data integrity, `InnoDB' also supports `FOREIGN KEY' referential-integrity constraints. * *Note `Memory': memory-storage-engine.: Stores all data in RAM for extremely fast access in environments that require quick lookups of reference and other like data. This engine was formerly known as the `HEAP' engine. * *Note `Merge': merge-storage-engine.: Enables a MySQL DBA or developer to logically group a series of identical `MyISAM' tables and reference them as one object. Good for VLDB environments such as data warehousing. * *Note `Archive': archive-storage-engine.: Provides the perfect solution for storing and retrieving large amounts of seldom-referenced historical, archived, or security audit information. * *Note `Federated': federated-storage-engine.: Offers the ability to link separate MySQL servers to create one logical database from many physical servers. Very good for distributed or data mart environments. * *Note *Note `NDBCLUSTER': mysql-cluster.: mysql-cluster. (also known as *Note `NDB': mysql-cluster.)--This clustered database engine is particularly suited for applications that require the highest possible degree of uptime and availability. *Note*: The *Note `NDBCLUSTER': mysql-cluster. storage engine is not supported in standard MySQL 5.1 releases. MySQL Cluster users wishing to upgrade from MySQL 5.0 should instead migrate to MySQL Cluster NDB 6.3, 7.0, or 7.1; these are based on MySQL 5.1 but contain the latest improvements and fixes for *Note `NDBCLUSTER': mysql-cluster. * *Note `CSV': csv-storage-engine.: The CSV storage engine stores data in text files using comma-separated values format. You can use the CSV engine to easily exchange data between other software and applications that can import and export in CSV format. * *Note `Blackhole': blackhole-storage-engine.: The Blackhole storage engine accepts but does not store data and retrievals always return an empty set. The functionality can be used in distributed database design where data is automatically replicated, but not stored locally. * *Note `Example': example-storage-engine.: The Example storage engine is `stub' engine that does nothing. You can create tables with this engine, but no data can be stored in them or retrieved from them. The purpose of this engine is to serve as an example in the MySQL source code that illustrates how to begin writing new storage engines. As such, it is primarily of interest to developers. It is important to remember that you are not restricted to using the same storage engine for an entire server or schema: you can use a different storage engine for each table in your schema. *Choosing a Storage Engine* The various storage engines provided with MySQL are designed with different use cases in mind. To use the pluggable storage architecture effectively, it is good to have an idea of the advantages and disadvantages of the various storage engines. The following table provides an overview of some storage engines provided with MySQL: *Storage Engine Features* Feature MyISAM Memory InnoDB Archive NDB Storage 256TB RAM 64TB None 384EB limits TransactionsNo No Yes No Yes Locking Table Table Row Row Row granularity MVCC No No Yes No No GeospatialYes No Yes Yes Yes data type support GeospatialYes No No No No indexing support B-tree Yes Yes Yes No Yes indexes Hash No Yes No InnoDB No Yes indexes utilizes hash indexes internally for its Adaptive Hash Index feature. Full-textYes No No No No search indexes ClusteredNo No Yes No No indexes Data No N/A Yes No Yes caches Index Yes N/A Yes No Yes caches CompressedYes No Yes Yes No data Compressed Compressed MyISAM InnoDB tables are tables supported require the only when InnoDB using the Barracuda compressed file format. row format. Tables using the compressed row format with MyISAM are read only. EncryptedYes Yes Yes Yes Yes data Implemented in the server (via encryption functions), rather than in the storage engine. Cluster No No No No Yes database support ReplicationYes Yes Yes Yes Yes support Implemented in the server, rather than in the storage product. Foreign No No Yes No No key support Backup Yes Yes Yes Yes Yes / point-in-time recovery Implemented in the server, rather than in the storage product. Query Yes Yes Yes Yes Yes cache support Update Yes Yes Yes Yes Yes statistics for data dictionary  File: manual.info, Node: storage-engine-compare-transactions, Next: storage-engines-other, Prev: storage-engines, Up: storage-engines 14.1 Comparing Transaction and Nontransaction Engines ===================================================== Transaction-safe tables (TSTs) have several advantages over nontransaction-safe tables (NTSTs): * They are safer. Even if MySQL crashes or you get hardware problems, you can get your data back, either by automatic recovery or from a backup plus the transaction log. * You can combine many statements and accept them all at the same time with the *Note `COMMIT': commit. statement (if autocommit is disabled). * You can execute *Note `ROLLBACK': commit. to ignore your changes (if autocommit is disabled). * If an update fails, all of your changes are reverted. (With nontransaction-safe tables, all changes that have taken place are permanent.) * Transaction-safe storage engines can provide better concurrency for tables that get many updates concurrently with reads. You can combine transaction-safe and nontransaction-safe tables in the same statements to get the best of both worlds. However, although MySQL supports several transaction-safe storage engines, for best results, you should not mix different storage engines within a transaction with autocommit disabled. For example, if you do this, changes to nontransaction-safe tables still are committed immediately and cannot be rolled back. For information about this and other problems that can occur in transactions that use mixed storage engines, see *Note commit::. Nontransaction-safe tables have several advantages of their own, all of which occur because there is no transaction overhead: * Much faster * Lower disk space requirements * Less memory required to perform updates  File: manual.info, Node: storage-engines-other, Next: storage-engine-setting, Prev: storage-engine-compare-transactions, Up: storage-engines 14.2 Other Storage Engines ========================== Other storage engines may be available from third parties and community members that have used the Custom Storage Engine interface. You can find more information on the list of third party storage engines on the MySQL Forge Storage Engines (http://forge.mysql.com/projects/search.php?t=tag&k=storage%20engine) page. *Note*: Third party engines are not supported by MySQL. For further information, documentation, installation guides, bug reporting or for any help or assistance with these engines, please contact the developer of the engine directly. Third party engines that are known to be available include the following; please see the MySQL Forge links provided for more information: * *PrimeBase XT (PBXT) (http://forge.mysql.com/projects/project.php?id=43)*: PBXT has been designed for modern, web-based, high concurrency environments. * *RitmarkFS (http://forge.mysql.com/projects/project.php?id=82)*: RitmarkFS enables you to access and manipulate the file system using SQL queries. RitmarkFS also supports file system replication and directory change tracking. * *Distributed Data Engine (http://forge.mysql.com/projects/project.php?id=91)*: The Distributed Data Engine is an Open Source project that is dedicated to provide a Storage Engine for distributed data according to workload statistics. * *mdbtools (http://forge.mysql.com/projects/project.php?id=98)*: A pluggable storage engine that enables read-only access to Microsoft Access `.mdb' database files. * *solidDB for MySQL (http://forge.mysql.com/projects/project.php?id=139)*: solidDB Storage Engine for MySQL is an open source, transactional storage engine for MySQL Server. It is designed for mission-critical implementations that require a robust, transactional database. solidDB Storage Engine for MySQL is a multi-threaded storage engine that supports full ACID compliance with all expected transaction isolation levels, row-level locking, and Multi-Version Concurrency Control (MVCC) with nonblocking reads and writes. * *BLOB Streaming Engine (MyBS) (http://www.blobstreaming.org/)*: The Scalable BLOB Streaming infrastructure for MySQL will transform MySQL into a scalable media server capable of streaming pictures, films, MP3 files and other binary and text objects (BLOBs) directly in and out of the database. * *The `InnoDB' Plugin (http://www.innodb.com/innodb_plugin/features/)*: The `InnoDB' Plugin for MySQL permits users to replace the `built-in' version of `InnoDB' in MySQL 5.1 with a new release of `InnoDB' that offers new features, improved performance, enhanced reliability and new capabilities for flexibility and ease of use. Among the new features of the `InnoDB' Plugin are `Fast index creation', table and index compression, file format management and new `INFORMATION_SCHEMA' tables. For more information on developing a customer storage engine that can be used with the Pluggable Storage Engine Architecture, see Writing a Custom Storage Engine (http://forge.mysql.com/wiki/MySQL_Internals_Custom_Engine) on MySQL Forge (http://forge.mysql.com/wiki).  File: manual.info, Node: storage-engine-setting, Next: pluggable-storage-overview, Prev: storage-engines-other, Up: storage-engines 14.3 Setting the Storage Engine =============================== When you create a new table, you can specify which storage engine to use by adding an `ENGINE' table option to the *Note `CREATE TABLE': create-table. statement: CREATE TABLE t (i INT) ENGINE = INNODB; If you omit the `ENGINE' option, the default storage engine is used. Normally, this is `MyISAM', but you can change it by using the `--default-storage-engine' server startup option, or by setting the `default-storage-engine' option in the `my.cnf' configuration file. You can set the default storage engine to be used during the current session by setting the `storage_engine' variable: SET storage_engine=MYISAM; When MySQL is installed on Windows using the MySQL Configuration Wizard, the `InnoDB' or `MyISAM' storage engine can be selected as the default. See *Note mysql-config-wizard-database-usage::. To convert a table from one storage engine to another, use an *Note `ALTER TABLE': alter-table. statement that indicates the new engine: ALTER TABLE t ENGINE = MYISAM; See *Note create-table::, and *Note alter-table::. If you try to use a storage engine that is not compiled in or that is compiled in but deactivated, MySQL instead creates a table using the default storage engine. This behavior is convenient when you want to copy tables between MySQL servers that support different storage engines. (For example, in a replication setup, perhaps your master server supports transactional storage engines for increased safety, but the slave servers use only nontransactional storage engines for greater speed.) This automatic substitution of the default storage engine for unavailable engines can be confusing for new MySQL users. A warning is generated whenever a storage engine is automatically changed. To prevent this from happening if the desired engine is unavailable, enable the `NO_ENGINE_SUBSTITUTION' SQL mode. In this case, an error occurs instead of a warning and the table is not created or altered if the desired engine is unavailable. See *Note server-sql-mode::. For new tables, MySQL always creates an `.frm' file to hold the table and column definitions. The table's index and data may be stored in one or more other files, depending on the storage engine. The server creates the `.frm' file above the storage engine level. Individual storage engines create any additional files required for the tables that they manage. If a table name contains special characters, the names for the table files contain encoded versions of those characters as described in *Note identifier-mapping::. A database may contain tables of different types. That is, tables need not all be created with the same storage engine.  File: manual.info, Node: pluggable-storage-overview, Next: myisam-storage-engine, Prev: storage-engine-setting, Up: storage-engines 14.4 Overview of MySQL Storage Engine Architecture ================================================== * Menu: * pluggable-storage:: Pluggable Storage Engine Architecture * pluggable-storage-common-layer:: The Common Database Server Layer The MySQL pluggable storage engine architecture enables a database professional to select a specialized storage engine for a particular application need while being completely shielded from the need to manage any specific application coding requirements. The MySQL server architecture isolates the application programmer and DBA from all of the low-level implementation details at the storage level, providing a consistent and easy application model and API. Thus, although there are different capabilities across different storage engines, the application is shielded from these differences. The MySQL pluggable storage engine architecture is shown in *Note figure-storage-engine-architecture::. FIGURE GOES HERE: MySQL Architecture with Pluggable Storage Engines The pluggable storage engine architecture provides a standard set of management and support services that are common among all underlying storage engines. The storage engines themselves are the components of the database server that actually perform actions on the underlying data that is maintained at the physical server level. This efficient and modular architecture provides huge benefits for those wishing to specifically target a particular application need--such as data warehousing, transaction processing, or high availability situations--while enjoying the advantage of utilizing a set of interfaces and services that are independent of any one storage engine. The application programmer and DBA interact with the MySQL database through Connector APIs and service layers that are above the storage engines. If application changes bring about requirements that demand the underlying storage engine change, or that one or more storage engines be added to support new needs, no significant coding or process changes are required to make things work. The MySQL server architecture shields the application from the underlying complexity of the storage engine by presenting a consistent and easy-to-use API that applies across storage engines.  File: manual.info, Node: pluggable-storage, Next: pluggable-storage-common-layer, Prev: pluggable-storage-overview, Up: pluggable-storage-overview 14.4.1 Pluggable Storage Engine Architecture -------------------------------------------- As of MySQL 5.1, MySQL Server uses a pluggable storage engine architecture that enables storage engines to be loaded into and unloaded from a running MySQL server. *Note*: Prior to MySQL 5.1.38, the pluggable storage engine architecture is supported on Unix platforms only and pluggable storage engines are not supported on Windows. *Plugging in a Storage Engine* Before a storage engine can be used, the storage engine plugin shared library must be loaded into MySQL using the *Note `INSTALL PLUGIN': install-plugin. statement. For example, if the `EXAMPLE' engine plugin is named `example' and the shared library is named `ha_example.so', you load it with the following statement: mysql> INSTALL PLUGIN example SONAME 'ha_example.so'; To install a pluggable storage engine, the plugin file must be located in the MySQL plugin directory, and the user issuing the *Note `INSTALL PLUGIN': install-plugin. statement must have `INSERT' privilege for the `mysql.plugin' table. The shared library must be located in the MySQL server plugin directory, the location of which is given by the `plugin_dir' system variable. *Unplugging a Storage Engine* To unplug a storage engine, use the *Note `UNINSTALL PLUGIN': uninstall-plugin. statement: mysql> UNINSTALL PLUGIN example; If you unplug a storage engine that is needed by existing tables, those tables become inaccessible, but will still be present on disk (where applicable). Ensure that there are no tables using a storage engine before you unplug the storage engine.  File: manual.info, Node: pluggable-storage-common-layer, Prev: pluggable-storage, Up: pluggable-storage-overview 14.4.2 The Common Database Server Layer --------------------------------------- A MySQL pluggable storage engine is the component in the MySQL database server that is responsible for performing the actual data I/O operations for a database as well as enabling and enforcing certain feature sets that target a specific application need. A major benefit of using specific storage engines is that you are only delivered the features needed for a particular application, and therefore you have less system overhead in the database, with the end result being more efficient and higher database performance. This is one of the reasons that MySQL has always been known to have such high performance, matching or beating proprietary monolithic databases in industry standard benchmarks. From a technical perspective, what are some of the unique supporting infrastructure components that are in a storage engine? Some of the key feature differentiations include: * _Concurrency_: Some applications have more granular lock requirements (such as row-level locks) than others. Choosing the right locking strategy can reduce overhead and therefore improve overall performance. This area also includes support for capabilities such as multi-version concurrency control or `snapshot' read. * _Transaction Support_: Not every application needs transactions, but for those that do, there are very well defined requirements such as ACID compliance and more. * _Referential Integrity_: The need to have the server enforce relational database referential integrity through DDL defined foreign keys. * _Physical Storage_: This involves everything from the overall page size for tables and indexes as well as the format used for storing data to physical disk. * _Index Support_: Different application scenarios tend to benefit from different index strategies. Each storage engine generally has its own indexing methods, although some (such as B-tree indexes) are common to nearly all engines. * _Memory Caches_: Different applications respond better to some memory caching strategies than others, so although some memory caches are common to all storage engines (such as those used for user connections or MySQL's high-speed Query Cache), others are uniquely defined only when a particular storage engine is put in play. * _Performance Aids_: This includes multiple I/O threads for parallel operations, thread concurrency, database checkpointing, bulk insert handling, and more. * _Miscellaneous Target Features_: This may include support for geospatial operations, security restrictions for certain data manipulation operations, and other similar features. Each set of the pluggable storage engine infrastructure components are designed to offer a selective set of benefits for a particular application. Conversely, avoiding a set of component features helps reduce unnecessary overhead. It stands to reason that understanding a particular application's set of requirements and selecting the proper MySQL storage engine can have a dramatic impact on overall system efficiency and performance.  File: manual.info, Node: myisam-storage-engine, Next: innodb-storage-engine, Prev: pluggable-storage-overview, Up: storage-engines 14.5 The `MyISAM' Storage Engine ================================ * Menu: * myisam-start:: `MyISAM' Startup Options * key-space:: Space Needed for Keys * myisam-table-formats:: `MyISAM' Table Storage Formats * myisam-table-problems:: `MyISAM' Table Problems `MyISAM' is the default storage engine. It is based on the older (and no longer available) `ISAM' storage engine but has many useful extensions. *`MyISAM' Storage Engine Features* *Storage limits* 256TB *Transactions* No *Locking Table granularity* *MVCC* No *Geospatial Yes *Geospatial Yes data type indexing support* support* *B-tree indexes* Yes *Hash indexes* No *Full-text Yes search indexes* *Clustered No *Data caches* No *Index caches* Yes indexes* *Compressed Yes *Encrypted data Yes *Cluster No data* CompressedImplemented in database MyISAM the server (via support* tables encryption are functions), supportedrather than in only the storage when engine.* using the compressed row format. Tables using the compressed row format with MyISAM are read only. *Replication Yes *Foreign key No *Backup / Yes support support* point-in-time Implemented in recovery the server, Implemented in rather than in the server, the storage rather than in product.* the storage product.* *Query cache Yes *Update Yes support* statistics for data dictionary* Each `MyISAM' table is stored on disk in three files. The files have names that begin with the table name and have an extension to indicate the file type. An `.frm' file stores the table format. The data file has an `.MYD' (`MYData') extension. The index file has an `.MYI' (`MYIndex') extension. To specify explicitly that you want a `MyISAM' table, indicate that with an `ENGINE' table option: CREATE TABLE t (i INT) ENGINE = MYISAM; Normally, it is unnecessary to use `ENGINE' to specify the `MyISAM' storage engine. `MyISAM' is the default engine unless the default has been changed. To ensure that `MyISAM' is used in situations where the default might have been changed, include the `ENGINE' option explicitly. You can check or repair `MyISAM' tables with the *Note `mysqlcheck': mysqlcheck. client or *Note `myisamchk': myisamchk. utility. You can also compress `MyISAM' tables with *Note `myisampack': myisampack. to take up much less space. See *Note mysqlcheck::, *Note myisamchk::, and *Note myisampack::. `MyISAM' tables have the following characteristics: * All data values are stored with the low byte first. This makes the data machine and operating system independent. The only requirements for binary portability are that the machine uses two's-complement signed integers and IEEE floating-point format. These requirements are widely used among mainstream machines. Binary compatibility might not be applicable to embedded systems, which sometimes have peculiar processors. There is no significant speed penalty for storing data low byte first; the bytes in a table row normally are unaligned and it takes little more processing to read an unaligned byte in order than in reverse order. Also, the code in the server that fetches column values is not time critical compared to other code. * All numeric key values are stored with the high byte first to permit better index compression. * Large files (up to 63-bit file length) are supported on file systems and operating systems that support large files. * There is a limit of 2^32 (~4.295E+09) rows in a `MyISAM' table. If you build MySQL with the `--with-big-tables' option, the row limitation is increased to (2^32)^2 (1.844E+19) rows. See *Note source-configuration-options::. Binary distributions for Unix and Linux are built with this option. * The maximum number of indexes per `MyISAM' table is 64. This can be changed by recompiling. Beginning with MySQL 5.1.4, you can configure the build by invoking `configure' with the `--with-max-indexes=N' option, where N is the maximum number of indexes to permit per `MyISAM' table. N must be less than or equal to 128. Before MySQL 5.1.4, you must change the source. The maximum number of columns per index is 16. * The maximum key length is 1000 bytes. This can also be changed by changing the source and recompiling. For the case of a key longer than 250 bytes, a larger key block size than the default of 1024 bytes is used. * When rows are inserted in sorted order (as when you are using an `AUTO_INCREMENT' column), the index tree is split so that the high node only contains one key. This improves space utilization in the index tree. * Internal handling of one `AUTO_INCREMENT' column per table is supported. `MyISAM' automatically updates this column for *Note `INSERT': insert. and *Note `UPDATE': update. operations. This makes `AUTO_INCREMENT' columns faster (at least 10%). Values at the top of the sequence are not reused after being deleted. (When an `AUTO_INCREMENT' column is defined as the last column of a multiple-column index, reuse of values deleted from the top of a sequence does occur.) The `AUTO_INCREMENT' value can be reset with *Note `ALTER TABLE': alter-table. or *Note `myisamchk': myisamchk. * Dynamic-sized rows are much less fragmented when mixing deletes with updates and inserts. This is done by automatically combining adjacent deleted blocks and by extending blocks if the next block is deleted. * `MyISAM' supports concurrent inserts: If a table has no free blocks in the middle of the data file, you can *Note `INSERT': insert. new rows into it at the same time that other threads are reading from the table. A free block can occur as a result of deleting rows or an update of a dynamic length row with more data than its current contents. When all free blocks are used up (filled in), future inserts become concurrent again. See *Note concurrent-inserts::. * You can put the data file and index file in different directories on different physical devices to get more speed with the `DATA DIRECTORY' and `INDEX DIRECTORY' table options to *Note `CREATE TABLE': create-table. See *Note create-table::. * *Note `BLOB': blob. and *Note `TEXT': blob. columns can be indexed. * `NULL' values are permitted in indexed columns. This takes 0 to 1 bytes per key. * Each character column can have a different character set. See *Note charset::. * There is a flag in the `MyISAM' index file that indicates whether the table was closed correctly. If *Note `mysqld': mysqld. is started with the `--myisam-recover' option, `MyISAM' tables are automatically checked when opened, and are repaired if the table wasn't closed properly. * *Note `myisamchk': myisamchk. marks tables as checked if you run it with the `--update-state' option. *Note `myisamchk --fast': myisamchk. checks only those tables that don't have this mark. * *Note `myisamchk --analyze': myisamchk. stores statistics for portions of keys, as well as for entire keys. * *Note `myisampack': myisampack. can pack *Note `BLOB': blob. and *Note `VARCHAR': char. columns. `MyISAM' also supports the following features: * Support for a true *Note `VARCHAR': char. type; a *Note `VARCHAR': char. column starts with a length stored in one or two bytes. * Tables with *Note `VARCHAR': char. columns may have fixed or dynamic row length. * The sum of the lengths of the *Note `VARCHAR': char. and *Note `CHAR': char. columns in a table may be up to 64KB. * Arbitrary length `UNIQUE' constraints. * Additional Resources * * A forum dedicated to the `MyISAM' storage engine is available at `http://forums.mysql.com/list.php?21'.  File: manual.info, Node: myisam-start, Next: key-space, Prev: myisam-storage-engine, Up: myisam-storage-engine 14.5.1 `MyISAM' Startup Options ------------------------------- The following options to *Note `mysqld': mysqld. can be used to change the behavior of `MyISAM' tables. For additional information, see *Note server-options::. *MyISAM Option/Variable Reference* Name Cmd-Line Option file System Var Status Var Var Scope Dynamic bulk_insert_buffer_sizeYes Yes Yes Both Yes concurrent_insertYes Yes Yes Global Yes delay-key-writeYes Yes Global Yes - _Variable_: Yes Global Yes delay_key_write have_rtree_keys Yes Global No key_buffer_sizeYes Yes Yes Global Yes log-isam Yes Yes myisam-block-sizeYes Yes myisam_data_pointer_sizeYes Yes Yes Global Yes myisam_max_sort_file_sizeYes Yes Yes Global Yes myisam_mmap_sizeYes Yes Yes Global No myisam-recover Yes Yes - _Variable_: myisam_recover_options myisam_recover_options Yes Global No myisam_repair_threadsYes Yes Yes Both Yes myisam_sort_buffer_sizeYes Yes Yes Both Yes myisam_stats_methodYes Yes Yes Both Yes myisam_use_mmapYes Yes Yes Global Yes skip-concurrent-insertYes Yes - _Variable_: concurrent_insert tmp_table_size Yes Yes Yes Both Yes * `--myisam-recover=MODE' Set the mode for automatic recovery of crashed `MyISAM' tables. * `--delay-key-write=ALL' Don't flush key buffers between writes for any `MyISAM' table. *Note*: If you do this, you should not access `MyISAM' tables from another program (such as from another MySQL server or with *Note `myisamchk': myisamchk.) when the tables are in use. Doing so risks index corruption. Using `--external-locking' does not eliminate this risk. The following system variables affect the behavior of `MyISAM' tables. For additional information, see *Note server-system-variables::. * `bulk_insert_buffer_size' The size of the tree cache used in bulk insert optimization. *Note*: This is a limit _per thread_! * `myisam_max_sort_file_size' The maximum size of the temporary file that MySQL is permitted to use while re-creating a `MyISAM' index (during *Note `REPAIR TABLE': repair-table, *Note `ALTER TABLE': alter-table, or *Note `LOAD DATA INFILE': load-data.). If the file size would be larger than this value, the index is created using the key cache instead, which is slower. The value is given in bytes. * `myisam_sort_buffer_size' Set the size of the buffer used when recovering tables. Automatic recovery is activated if you start *Note `mysqld': mysqld. with the `--myisam-recover' option. In this case, when the server opens a `MyISAM' table, it checks whether the table is marked as crashed or whether the open count variable for the table is not 0 and you are running the server with external locking disabled. If either of these conditions is true, the following happens: * The server checks the table for errors. * If the server finds an error, it tries to do a fast table repair (with sorting and without re-creating the data file). * If the repair fails because of an error in the data file (for example, a duplicate-key error), the server tries again, this time re-creating the data file. * If the repair still fails, the server tries once more with the old repair option method (write row by row without sorting). This method should be able to repair any type of error and has low disk space requirements. If the recovery wouldn't be able to recover all rows from previously completed statements and you didn't specify `FORCE' in the value of the `--myisam-recover' option, automatic repair aborts with an error message in the error log: Error: Couldn't repair table: test.g00pages If you specify `FORCE', a warning like this is written instead: Warning: Found 344 of 354 rows when repairing ./test/g00pages Note that if the automatic recovery value includes `BACKUP', the recovery process creates files with names of the form `TBL_NAME-DATETIME.BAK'. You should have a `cron' script that automatically moves these files from the database directories to backup media.  File: manual.info, Node: key-space, Next: myisam-table-formats, Prev: myisam-start, Up: myisam-storage-engine 14.5.2 Space Needed for Keys ---------------------------- `MyISAM' tables use B-tree indexes. You can roughly calculate the size for the index file as `(key_length+4)/0.67', summed over all keys. This is for the worst case when all keys are inserted in sorted order and the table doesn't have any compressed keys. String indexes are space compressed. If the first index part is a string, it is also prefix compressed. Space compression makes the index file smaller than the worst-case figure if a string column has a lot of trailing space or is a *Note `VARCHAR': char. column that is not always used to the full length. Prefix compression is used on keys that start with a string. Prefix compression helps if there are many strings with an identical prefix. In `MyISAM' tables, you can also prefix compress numbers by specifying the `PACK_KEYS=1' table option when you create the table. Numbers are stored with the high byte first, so this helps when you have many integer keys that have an identical prefix.  File: manual.info, Node: myisam-table-formats, Next: myisam-table-problems, Prev: key-space, Up: myisam-storage-engine 14.5.3 `MyISAM' Table Storage Formats ------------------------------------- * Menu: * static-format:: Static (Fixed-Length) Table Characteristics * dynamic-format:: Dynamic Table Characteristics * compressed-format:: Compressed Table Characteristics `MyISAM' supports three different storage formats. Two of them, fixed and dynamic format, are chosen automatically depending on the type of columns you are using. The third, compressed format, can be created only with the *Note `myisampack': myisampack. utility (see *Note myisampack::). When you use *Note `CREATE TABLE': create-table. or *Note `ALTER TABLE': alter-table. for a table that has no *Note `BLOB': blob. or *Note `TEXT': blob. columns, you can force the table format to *Note `FIXED': numeric-types. or `DYNAMIC' with the `ROW_FORMAT' table option. See *Note create-table::, for information about `ROW_FORMAT'. You can decompress (unpack) compressed `MyISAM' tables using *Note `myisamchk `--unpack'': myisamchk.; see *Note myisamchk::, for more information.  File: manual.info, Node: static-format, Next: dynamic-format, Prev: myisam-table-formats, Up: myisam-table-formats 14.5.3.1 Static (Fixed-Length) Table Characteristics .................................................... Static format is the default for `MyISAM' tables. It is used when the table contains no variable-length columns (*Note `VARCHAR': char, *Note `VARBINARY': binary-varbinary, *Note `BLOB': blob, or *Note `TEXT': blob.). Each row is stored using a fixed number of bytes. Of the three `MyISAM' storage formats, static format is the simplest and most secure (least subject to corruption). It is also the fastest of the on-disk formats due to the ease with which rows in the data file can be found on disk: To look up a row based on a row number in the index, multiply the row number by the row length to calculate the row position. Also, when scanning a table, it is very easy to read a constant number of rows with each disk read operation. The security is evidenced if your computer crashes while the MySQL server is writing to a fixed-format `MyISAM' file. In this case, *Note `myisamchk': myisamchk. can easily determine where each row starts and ends, so it can usually reclaim all rows except the partially written one. Note that `MyISAM' table indexes can always be reconstructed based on the data rows. *Note*: Fixed-length row format is only available for tables without *Note `BLOB': blob. or *Note `TEXT': blob. columns. Creating a table with these columns with an explicit `ROW_FORMAT' clause will not raise an error or warning; the format specification will be ignored. Static-format tables have these characteristics: * *Note `CHAR': char. and *Note `VARCHAR': char. columns are space-padded to the specified column width, although the column type is not altered. *Note `BINARY': binary-varbinary. and *Note `VARBINARY': binary-varbinary. columns are padded with `0x00' bytes to the column width. * Very quick. * Easy to cache. * Easy to reconstruct after a crash, because rows are located in fixed positions. * Reorganization is unnecessary unless you delete a huge number of rows and want to return free disk space to the operating system. To do this, use *Note `OPTIMIZE TABLE': optimize-table. or *Note `myisamchk -r': myisamchk. * Usually require more disk space than dynamic-format tables.  File: manual.info, Node: dynamic-format, Next: compressed-format, Prev: static-format, Up: myisam-table-formats 14.5.3.2 Dynamic Table Characteristics ...................................... Dynamic storage format is used if a `MyISAM' table contains any variable-length columns (*Note `VARCHAR': char, *Note `VARBINARY': binary-varbinary, *Note `BLOB': blob, or *Note `TEXT': blob.), or if the table was created with the `ROW_FORMAT=DYNAMIC' table option. Dynamic format is a little more complex than static format because each row has a header that indicates how long it is. A row can become fragmented (stored in noncontiguous pieces) when it is made longer as a result of an update. You can use *Note `OPTIMIZE TABLE': optimize-table. or *Note `myisamchk -r': myisamchk. to defragment a table. If you have fixed-length columns that you access or change frequently in a table that also contains some variable-length columns, it might be a good idea to move the variable-length columns to other tables just to avoid fragmentation. Dynamic-format tables have these characteristics: * All string columns are dynamic except those with a length less than four. * Each row is preceded by a bitmap that indicates which columns contain the empty string (for string columns) or zero (for numeric columns). Note that this does not include columns that contain `NULL' values. If a string column has a length of zero after trailing space removal, or a numeric column has a value of zero, it is marked in the bitmap and not saved to disk. Nonempty strings are saved as a length byte plus the string contents. * Much less disk space usually is required than for fixed-length tables. * Each row uses only as much space as is required. However, if a row becomes larger, it is split into as many pieces as are required, resulting in row fragmentation. For example, if you update a row with information that extends the row length, the row becomes fragmented. In this case, you may have to run *Note `OPTIMIZE TABLE': optimize-table. or *Note `myisamchk -r': myisamchk. from time to time to improve performance. Use *Note `myisamchk -ei': myisamchk. to obtain table statistics. * More difficult than static-format tables to reconstruct after a crash, because rows may be fragmented into many pieces and links (fragments) may be missing. * The expected row length for dynamic-sized rows is calculated using the following expression: 3 + (NUMBER OF COLUMNS + 7) / 8 + (NUMBER OF CHAR COLUMNS) + (PACKED SIZE OF NUMERIC COLUMNS) + (LENGTH OF STRINGS) + (NUMBER OF NULL COLUMNS + 7) / 8 There is a penalty of 6 bytes for each link. A dynamic row is linked whenever an update causes an enlargement of the row. Each new link is at least 20 bytes, so the next enlargement probably goes in the same link. If not, another link is created. You can find the number of links using *Note `myisamchk -ed': myisamchk. All links may be removed with *Note `OPTIMIZE TABLE': optimize-table. or *Note `myisamchk -r': myisamchk.  File: manual.info, Node: compressed-format, Prev: dynamic-format, Up: myisam-table-formats 14.5.3.3 Compressed Table Characteristics ......................................... Compressed storage format is a read-only format that is generated with the *Note `myisampack': myisampack. tool. Compressed tables can be uncompressed with *Note `myisamchk': myisamchk. Compressed tables have the following characteristics: * Compressed tables take very little disk space. This minimizes disk usage, which is helpful when using slow disks (such as CD-ROMs). * Each row is compressed separately, so there is very little access overhead. The header for a row takes up one to three bytes depending on the biggest row in the table. Each column is compressed differently. There is usually a different Huffman tree for each column. Some of the compression types are: * Suffix space compression. * Prefix space compression. * Numbers with a value of zero are stored using one bit. * If values in an integer column have a small range, the column is stored using the smallest possible type. For example, a *Note `BIGINT': numeric-types. column (eight bytes) can be stored as a *Note `TINYINT': numeric-types. column (one byte) if all its values are in the range from `-128' to `127'. * If a column has only a small set of possible values, the data type is converted to *Note `ENUM': enum. * A column may use any combination of the preceding compression types. * Can be used for fixed-length or dynamic-length rows. *Note*: While a compressed table is read only, and you cannot therefore update or add rows in the table, DDL (Data Definition Language) operations are still valid. For example, you may still use `DROP' to drop the table, and *Note `TRUNCATE TABLE': truncate-table. to empty the table.  File: manual.info, Node: myisam-table-problems, Prev: myisam-table-formats, Up: myisam-storage-engine 14.5.4 `MyISAM' Table Problems ------------------------------ * Menu: * corrupted-myisam-tables:: Corrupted `MyISAM' Tables * myisam-table-close:: Problems from Tables Not Being Closed Properly The file format that MySQL uses to store data has been extensively tested, but there are always circumstances that may cause database tables to become corrupted. The following discussion describes how this can happen and how to handle it.  File: manual.info, Node: corrupted-myisam-tables, Next: myisam-table-close, Prev: myisam-table-problems, Up: myisam-table-problems 14.5.4.1 Corrupted `MyISAM' Tables .................................. Even though the `MyISAM' table format is very reliable (all changes to a table made by an SQL statement are written before the statement returns), you can still get corrupted tables if any of the following events occur: * The *Note `mysqld': mysqld. process is killed in the middle of a write. * An unexpected computer shutdown occurs (for example, the computer is turned off). * Hardware failures. * You are using an external program (such as *Note `myisamchk': myisamchk.) to modify a table that is being modified by the server at the same time. * A software bug in the MySQL or `MyISAM' code. Typical symptoms of a corrupt table are: * You get the following error while selecting data from the table: Incorrect key file for table: '...'. Try to repair it * Queries don't find rows in the table or return incomplete results. You can check the health of a `MyISAM' table using the *Note `CHECK TABLE': check-table. statement, and repair a corrupted `MyISAM' table with *Note `REPAIR TABLE': repair-table. When *Note `mysqld': mysqld. is not running, you can also check or repair a table with the *Note `myisamchk': myisamchk. command. See *Note check-table::, *Note repair-table::, and *Note myisamchk::. If your tables become corrupted frequently, you should try to determine why this is happening. The most important thing to know is whether the table became corrupted as a result of a server crash. You can verify this easily by looking for a recent `restarted mysqld' message in the error log. If there is such a message, it is likely that table corruption is a result of the server dying. Otherwise, corruption may have occurred during normal operation. This is a bug. You should try to create a reproducible test case that demonstrates the problem. See *Note crashing::, and MySQL Internals: Porting (http://forge.mysql.com/wiki/MySQL_Internals_Porting).  File: manual.info, Node: myisam-table-close, Prev: corrupted-myisam-tables, Up: myisam-table-problems 14.5.4.2 Problems from Tables Not Being Closed Properly ....................................................... Each `MyISAM' index file (`.MYI' file) has a counter in the header that can be used to check whether a table has been closed properly. If you get the following warning from *Note `CHECK TABLE': check-table. or *Note `myisamchk': myisamchk, it means that this counter has gone out of sync: clients are using or haven't closed the table properly This warning doesn't necessarily mean that the table is corrupted, but you should at least check the table. The counter works as follows: * The first time a table is updated in MySQL, a counter in the header of the index files is incremented. * The counter is not changed during further updates. * When the last instance of a table is closed (because a *Note `FLUSH TABLES': flush. operation was performed or because there is no room in the table cache), the counter is decremented if the table has been updated at any point. * When you repair the table or check the table and it is found to be okay, the counter is reset to zero. * To avoid problems with interaction with other processes that might check the table, the counter is not decremented on close if it was zero. In other words, the counter can become incorrect only under these conditions: * A `MyISAM' table is copied without first issuing *Note `LOCK TABLES': lock-tables. and *Note `FLUSH TABLES': flush. * MySQL has crashed between an update and the final close. (Note that the table may still be okay, because MySQL always issues writes for everything between each statement.) * A table was modified by *Note `myisamchk --recover': myisamchk. or *Note `myisamchk --update-state': myisamchk. at the same time that it was in use by *Note `mysqld': mysqld. * Multiple *Note `mysqld': mysqld. servers are using the table and one server performed a *Note `REPAIR TABLE': repair-table. or *Note `CHECK TABLE': check-table. on the table while it was in use by another server. In this setup, it is safe to use *Note `CHECK TABLE': check-table, although you might get the warning from other servers. However, *Note `REPAIR TABLE': repair-table. should be avoided because when one server replaces the data file with a new one, this is not known to the other servers. In general, it is a bad idea to share a data directory among multiple servers. See *Note multiple-servers::, for additional discussion.  File: manual.info, Node: innodb-storage-engine, Next: se-db2, Prev: myisam-storage-engine, Up: storage-engines 14.6 The `InnoDB' Storage Engine ================================ * Menu: * innodb-contact-information:: `InnoDB' Contact Information * innodb-configuration:: Configuring `InnoDB' * innodb-parameters:: `InnoDB' Startup Options and System Variables * using-innodb-tables:: Creating and Using `InnoDB' Tables * innodb-data-log-reconfiguration:: Adding, Removing, or Resizing `InnoDB' Data and Log Files * innodb-backup:: Backing Up and Recovering an `InnoDB' Database * innodb-migration:: Moving an `InnoDB' Database to Another Machine * innodb-transaction-model:: The `InnoDB' Transaction Model and Locking * innodb-multi-versioning:: `InnoDB' Multi-Versioning * innodb-table-and-index:: `InnoDB' Table and Index Structures * innodb-disk-management:: `InnoDB' Disk I/O and File Space Management * innodb-error-handling:: `InnoDB' Error Handling * innodb-tuning-troubleshooting:: `InnoDB' Performance Tuning and Troubleshooting * innodb-restrictions:: Restrictions on `InnoDB' Tables `InnoDB' is a transaction-safe (ACID compliant) storage engine for MySQL that has commit, rollback, and crash-recovery capabilities to protect user data. `InnoDB' row-level locking (without escalation to coarser granularity locks) and Oracle-style consistent nonlocking reads increase multi-user concurrency and performance. `InnoDB' stores user data in clustered indexes to reduce I/O for common queries based on primary keys. To maintain data integrity, `InnoDB' also supports `FOREIGN KEY' referential-integrity constraints. You can freely mix `InnoDB' tables with tables from other MySQL storage engines, even within the same statement. To determine whether your server supports `InnoDB' use the *Note `SHOW ENGINES': show-engines. statement. See *Note show-engines::. *`InnoDB' Storage Engine Features* *Storage limits* 64TB *Transactions* Yes *Locking Row granularity* *MVCC* Yes *Geospatial Yes *Geospatial No data type indexing support* support* *B-tree indexes* Yes *Hash indexes* No *Full-text No InnoDB search indexes* utilizes hash indexes internally for its Adaptive Hash Index feature. *Clustered Yes *Data caches* Yes *Index caches* Yes indexes* *Compressed Yes *Encrypted data Yes *Cluster No data* CompressedImplemented in database InnoDB the server (via support* tables encryption require functions), the rather than in InnoDB the storage Barracudaengine.* file format. *Replication Yes *Foreign key Yes *Backup / Yes support support* point-in-time Implemented in recovery the server, Implemented in rather than in the server, the storage rather than in product.* the storage product.* *Query cache Yes *Update Yes support* statistics for data dictionary* `InnoDB' has been designed for maximum performance when processing large data volumes. Its CPU efficiency is probably not matched by any other disk-based relational database engine. The `InnoDB' storage engine maintains its own buffer pool for caching data and indexes in main memory. `InnoDB' stores its tables and indexes in a tablespace, which may consist of several files (or raw disk partitions). This is different from, for example, `MyISAM' tables where each table is stored using separate files. `InnoDB' tables can be very large even on operating systems where file size is limited to 2GB. The Windows Essentials installer makes `InnoDB' the MySQL default storage engine on Windows, if the server being installed supports `InnoDB'. `InnoDB' is used in production at numerous large database sites requiring high performance. The famous Internet news site Slashdot.org runs on `InnoDB'. Mytrix, Inc. stores more than 1TB of data in `InnoDB', and another site handles an average load of 800 inserts/updates per second in `InnoDB'. `InnoDB' is published under the same GNU GPL License Version 2 (of June 1991) as MySQL. For more information on MySQL licensing, see http://www.mysql.com/company/legal/licensing/. * Additional Resources * * A forum dedicated to the `InnoDB' storage engine is available at `http://forums.mysql.com/list.php?22'. * Innobase Oy also hosts several forums, available at `http://forums.innodb.com'. * At the 2008 MySQL User Conference, Innobase announced availability of an `InnoDB' Plugin for MySQL. This plugin for MySQL exploits the `pluggable storage engine' architecture of MySQL, to permit users to replace the `built-in' version of `InnoDB' in MySQL 5.1. As of MySQL 5.1.38, the `InnoDB Plugin' is included in MySQL 5.1 releases, in addition to the built-in version of `InnoDB' that has been included in previous releases. MySQL 5.1.42 through 5.1.45 include `InnoDB Plugin' 1.0.6, which is considered of Release Candidate (RC) quality. MySQL 5.1.46 and up include `InnoDB Plugin' 1.0.7 or higher, which is considered of General Availability (GA) quality. Prior to MySQL Cluster NDB 7.1.11, MySQL Cluster was not compatible with the `InnoDB Plugin'. The `InnoDB Plugin' offers new features, improved performance and scalability, enhanced reliability and new capabilities for flexibility and ease of use. Among the features of the `InnoDB Plugin' are `Fast index creation,' table and index compression, file format management, new `INFORMATION_SCHEMA' tables, capacity tuning, multiple background I/O threads, and group commit. For information about these features, see InnoDB Plugin 1.0 for MySQL 5.1 User's Guide (http://dev.mysql.com/doc/innodb-plugin/1.0/en/index.html). The `InnoDB Plugin' is included in source and binary distributions, except RHEL3, RHEL4, SuSE 9 (x86, x86_64, ia64), and generic Linux RPM packages. For instructions on replacing the built-in version of `InnoDB' with `InnoDB Plugin', see *Note replacing-builtin-innodb::. * The MySQL Enterprise Backup product lets you back up a running MySQL database, including `InnoDB' and `MyISAM' tables, with minimal disruption to operations while producing a consistent snapshot of the database. When MySQL Enterprise Backup is copying `InnoDB' tables, reads and writes to both `InnoDB' and `MyISAM' tables can continue. During the copying of `MyISAM' and other non-InnoDB tables, reads (but not writes) to those tables are permitted. In addition, MySQL Enterprise Backup can create compressed backup files, and back up subsets of `InnoDB' tables. In conjunction with the MySQL binary log, you can perform point-in-time recovery. MySQL Enterprise Backup is included as part of the MySQL Enterprise subscription. For a more complete description of MySQL Enterprise Backup, see MySQL Enterprise Backup User's Guide (Version 3.5.4) (http://dev.mysql.com/doc/mysql-enterprise-backup/3.5/en/index.html).  File: manual.info, Node: innodb-contact-information, Next: innodb-configuration, Prev: innodb-storage-engine, Up: innodb-storage-engine 14.6.1 `InnoDB' Contact Information ----------------------------------- Contact information for Innobase Oy, producer of the `InnoDB' engine: Web site: `http://www.innodb.com/' Email: `innodb_sales_ww at oracle.com' or use this contact form: `http://www.innodb.com/contact-form' Phone: +358-9-6969 3250 (office, Heikki Tuuri) +358-40-5617367 (mobile, Heikki Tuuri) +358-40-5939732 (mobile, Satu Sire'n) Address: Innobase Oy Inc. World Trade Center Helsinki Aleksanterinkatu 17 P.O.Box 800 00101 Helsinki Finland  File: manual.info, Node: innodb-configuration, Next: innodb-parameters, Prev: innodb-contact-information, Up: innodb-storage-engine 14.6.2 Configuring `InnoDB' --------------------------- * Menu: * replacing-builtin-innodb:: Using `InnoDB Plugin' Instead of the Built-In `InnoDB' * innodb-multiple-tablespaces:: Using Per-Table Tablespaces * innodb-raw-devices:: Using Raw Devices for the Shared Tablespace * innodb-init:: Creating the `InnoDB' Tablespace * error-creating-innodb:: Dealing with `InnoDB' Initialization Problems The first decisions to make about InnoDB configuration involve how to lay out InnoDB data files, and how much memory to allocate for the InnoDB storage engine. You record these choices either by recording them in a configuration file that MySQL reads at startup, or by specifying them as command-line options in a startup script. * Overview of InnoDB Tablespace and Log Files * Two important disk-based resources managed by the `InnoDB' storage engine are its tablespace data files and its log files. If you specify no `InnoDB' configuration options, MySQL creates an auto-extending 10MB data file named `ibdata1' and two 5MB log files named `ib_logfile0' and `ib_logfile1' in the MySQL data directory. To get good performance, explicitly provide `InnoDB' parameters as discussed in the following examples. Edit the settings to suit your hardware and requirements. The examples shown here are representative. See *Note innodb-parameters:: for additional information about `InnoDB'-related configuration parameters. * Considerations for Storage Devices * In some cases, database performance improves if the data is not all placed on the same physical disk. Putting log files on a different disk from data is very often beneficial for performance. The example illustrates how to do this. It places the two data files on different disks and places the log files on the third disk. `InnoDB' fills the tablespace beginning with the first data file. You can also use raw disk partitions (raw devices) as `InnoDB' data files, which may speed up I/O. See *Note innodb-raw-devices::. *Caution*: `InnoDB' is a transaction-safe (ACID compliant) storage engine for MySQL that has commit, rollback, and crash-recovery capabilities to protect user data. *However, it cannot do so* if the underlying operating system or hardware does not work as advertised. Many operating systems or disk subsystems may delay or reorder write operations to improve performance. On some operating systems, the very `fsync()' system call that should wait until all unwritten data for a file has been flushed might actually return before the data has been flushed to stable storage. Because of this, an operating system crash or a power outage may destroy recently committed data, or in the worst case, even corrupt the database because of write operations having been reordered. If data integrity is important to you, perform some `pull-the-plug' tests before using anything in production. On Mac OS X 10.3 and up, `InnoDB' uses a special `fcntl()' file flush method. Under Linux, it is advisable to *disable the write-back cache*. On ATA/SATA disk drives, a command such `hdparm -W0 /dev/hda' may work to disable the write-back cache. *Beware that some drives or disk controllers may be unable to disable the write-back cache.* *Caution*: If reliability is a consideration for your data, do not configure `InnoDB' to use data files or log files on NFS volumes. Potential problems vary according to OS and version of NFS, and include such issues as lack of protection from conflicting writes, and limitations on maximum file sizes. * Specifying the Location and Size for InnoDB Tablespace Files * To set up the `InnoDB' tablespace files, use the `innodb_data_file_path' option in the `[mysqld]' section of the `my.cnf' option file. On Windows, you can use `my.ini' instead. The value of `innodb_data_file_path' should be a list of one or more data file specifications. If you name more than one data file, separate them by semicolon (``;'') characters: innodb_data_file_path=DATAFILE_SPEC1[;DATAFILE_SPEC2]... For example, the following setting explicitly creates a tablespace having the same characteristics as the default: [mysqld] innodb_data_file_path=ibdata1:10M:autoextend This setting configures a single 10MB data file named `ibdata1' that is auto-extending. No location for the file is given, so by default, `InnoDB' creates it in the MySQL data directory. Sizes are specified using `K', `M', or `G' suffix letters to indicate units of KB, MB, or GB. A tablespace containing a fixed-size 50MB data file named `ibdata1' and a 50MB auto-extending file named `ibdata2' in the data directory can be configured like this: [mysqld] innodb_data_file_path=ibdata1:50M;ibdata2:50M:autoextend The full syntax for a data file specification includes the file name, its size, and several optional attributes: FILE_NAME:FILE_SIZE[:autoextend[:max:MAX_FILE_SIZE]] The `autoextend' and `max' attributes can be used only for the last data file in the `innodb_data_file_path' line. If you specify the `autoextend' option for the last data file, `InnoDB' extends the data file if it runs out of free space in the tablespace. The increment is 8MB at a time by default. To modify the increment, change the `innodb_autoextend_increment' system variable. If the disk becomes full, you might want to add another data file on another disk. For tablespace reconfiguration instructions, see *Note innodb-data-log-reconfiguration::. `InnoDB' is not aware of the file system maximum file size, so be cautious on file systems where the maximum file size is a small value such as 2GB. To specify a maximum size for an auto-extending data file, use the `max' attribute following the `autoextend' attribute. Use the `max' attribute only in cases where constraining disk usage is of critical importance, because exceeding the maximum size causes a fatal error, possibly including a crash. The following configuration permits `ibdata1' to grow up to a limit of 500MB: [mysqld] innodb_data_file_path=ibdata1:10M:autoextend:max:500M `InnoDB' creates tablespace files in the MySQL data directory by default. To specify a location explicitly, use the `innodb_data_home_dir' option. For example, to use two files named `ibdata1' and `ibdata2' but create them in the `/ibdata' directory, configure `InnoDB' like this: [mysqld] innodb_data_home_dir = /ibdata innodb_data_file_path=ibdata1:50M;ibdata2:50M:autoextend *Note*: `InnoDB' does not create directories, so make sure that the `/ibdata' directory exists before you start the server. This is also true of any log file directories that you configure. Use the Unix or DOS `mkdir' command to create any necessary directories. Make sure that the MySQL server has the proper access rights to create files in the data directory. More generally, the server must have access rights in any directory where it needs to create data files or log files. `InnoDB' forms the directory path for each data file by textually concatenating the value of `innodb_data_home_dir' to the data file name, adding a path name separator (slash or backslash) between values if necessary. If the `innodb_data_home_dir' option is not mentioned in `my.cnf' at all, the default value is the `dot' directory `./', which means the MySQL data directory. (The MySQL server changes its current working directory to its data directory when it begins executing.) If you specify `innodb_data_home_dir' as an empty string, you can specify absolute paths for the data files listed in the `innodb_data_file_path' value. The following example is equivalent to the preceding one: [mysqld] innodb_data_home_dir = innodb_data_file_path=/ibdata/ibdata1:50M;/ibdata/ibdata2:50M:autoextend * Specifying InnoDB Configuration Options * *Sample `my.cnf' file for small systems.* Suppose that you have a computer with 512MB RAM and one hard disk. The following example shows possible configuration parameters in `my.cnf' or `my.ini' for `InnoDB', including the `autoextend' attribute. The example suits most users, both on Unix and Windows, who do not want to distribute `InnoDB' data files and log files onto several disks. It creates an auto-extending data file `ibdata1' and two `InnoDB' log files `ib_logfile0' and `ib_logfile1' in the MySQL data directory. [mysqld] # You can write your other MySQL server options here # ... # Data files must be able to hold your data and indexes. # Make sure that you have enough free disk space. innodb_data_file_path = ibdata1:10M:autoextend # # Set buffer pool size to 50-80% of your computer's memory innodb_buffer_pool_size=256M innodb_additional_mem_pool_size=20M # # Set the log file size to about 25% of the buffer pool size innodb_log_file_size=64M innodb_log_buffer_size=8M # innodb_flush_log_at_trx_commit=1 Note that data files must be less than 2GB in some file systems. The combined size of the log files must be less than 4GB. The combined size of data files must be at least 10MB. * Setting Up the InnoDB System Tablespace * When you create an `InnoDB' tablespace for the first time, it is best that you start the MySQL server from the command prompt. `InnoDB' then prints the information about the database creation to the screen, so you can see what is happening. For example, on Windows, if *Note `mysqld': mysqld. is located in `C:\Program Files\MySQL\MySQL Server 5.1\bin', you can start it like this: C:\> "C:\Program Files\MySQL\MySQL Server 5.1\bin\mysqld" --console If you do not send server output to the screen, check the server's error log to see what `InnoDB' prints during the startup process. For an example of what the information displayed by `InnoDB' should look like, see *Note innodb-init::. * Editing the MySQL Configuration File * You can place `InnoDB' options in the `[mysqld]' group of any option file that your server reads when it starts. The locations for option files are described in *Note option-files::. If you installed MySQL on Windows using the installation and configuration wizards, the option file will be the `my.ini' file located in your MySQL installation directory. See The Location of the my.ini File (http://dev.mysql.com/doc/refman/5.0/en/windows-config-wizard.html#mysql-config-wizard-file-location). If your PC uses a boot loader where the `C:' drive is not the boot drive, your only option is to use the `my.ini' file in your Windows directory (typically `C:\WINDOWS'). You can use the `SET' command at the command prompt in a console window to print the value of `WINDIR': C:\> SET WINDIR windir=C:\WINDOWS To make sure that *Note `mysqld': mysqld. reads options only from a specific file, use the `--defaults-file' option as the first option on the command line when starting the server: mysqld --defaults-file=YOUR_PATH_TO_MY_CNF *Sample `my.cnf' file for large systems.* Suppose that you have a Linux computer with 2GB RAM and three 60GB hard disks at directory paths `/', `/dr2' and `/dr3'. The following example shows possible configuration parameters in `my.cnf' for `InnoDB'. [mysqld] # You can write your other MySQL server options here # ... innodb_data_home_dir = # # Data files must be able to hold your data and indexes innodb_data_file_path = /db/ibdata1:2000M;/dr2/db/ibdata2:2000M:autoextend # # Set buffer pool size to 50-80% of your computer's memory, # but make sure on Linux x86 total memory usage is < 2GB innodb_buffer_pool_size=1G innodb_additional_mem_pool_size=20M innodb_log_group_home_dir = /dr3/iblogs # # Set the log file size to about 25% of the buffer pool size innodb_log_file_size=250M innodb_log_buffer_size=8M # innodb_flush_log_at_trx_commit=1 innodb_lock_wait_timeout=50 # # Uncomment the next line if you want to use it #innodb_thread_concurrency=5 * Determining the Maximum Memory Allocation for InnoDB * *Warning*: On 32-bit GNU/Linux x86, be careful not to set memory usage too high. `glibc' may permit the process heap to grow over thread stacks, which crashes your server. It is a risk if the value of the following expression is close to or exceeds 2GB: innodb_buffer_pool_size + key_buffer_size + max_connections*(sort_buffer_size+read_buffer_size+binlog_cache_size) + max_connections*2MB Each thread uses a stack (often 2MB, but only 256KB in MySQL binaries provided by Oracle Corporation.) and in the worst case also uses `sort_buffer_size + read_buffer_size' additional memory. *Tuning other *Note `mysqld': mysqld. server parameters.* The following values are typical and suit most users: [mysqld] skip-external-locking max_connections=200 read_buffer_size=1M sort_buffer_size=1M # # Set key_buffer to 5 - 50% of your RAM depending on how much # you use MyISAM tables, but keep key_buffer_size + InnoDB # buffer pool size < 80% of your RAM key_buffer_size=VALUE On Linux, if the kernel is enabled for large page support, `InnoDB' can use large pages to allocate memory for its buffer pool and additional memory pool. See *Note large-page-support::. * Enabling the InnoDB Plugin * If you want to use `InnoDB Plugin' rather than the built-in version of `InnoDB', to get the latest performance improvements and new features such as table compression and fast index creation, see *Note replacing-builtin-innodb::. * Turning Off InnoDB * If you do not want to use `InnoDB' tables, start the server with the `--innodb=OFF' or `--skip-innodb' option to disable the `InnoDB' storage engine. In this case, the server will not start if the default storage engine is set to *Note `InnoDB': innodb-storage-engine. Use `--default-storage-engine' to set the default to some other engine if necessary.  File: manual.info, Node: replacing-builtin-innodb, Next: innodb-multiple-tablespaces, Prev: innodb-configuration, Up: innodb-configuration 14.6.2.1 Using `InnoDB Plugin' Instead of the Built-In `InnoDB' ............................................................... To use `InnoDB Plugin' in MySQL 5.1, you must disable the built-in version of `InnoDB' that is also included and instruct the server to use `InnoDB Plugin' instead. To accomplish this, use the following lines in your `my.cnf' file: [mysqld] ignore-builtin-innodb plugin-load=innodb=ha_innodb_plugin.so For the `plugin-load' option, `innodb' is the name to associate with the plugin and `ha_innodb_plugin.so' is the name of the shared object library that contains the plugin code. The extension of `.so' applies for Unix (and similar) systems. For HP-UX on HPPA (11.11) or Windows, the extension should be `.sl' or `.dll', respectively, rather than `.so'. If the server has problems finding the plugin when it starts up, specify the pathname to the plugin directory. For example, if plugins are located in the `lib/mysql/plugin' directory under the MySQL installation directory and you have installed MySQL at `/usr/local/mysql', use these lines in your `my.cnf' file: [mysqld] ignore-builtin-innodb plugin-load=innodb=ha_innodb_plugin.so plugin_dir=/usr/local/mysql/lib/mysql/plugin The previous examples show how to activate the storage engine part of `InnoDB Plugin,' but the plugin also implements several InnoDB-related `INFORMATION_SCHEMA' tables. (For information about these tables, see InnoDB `INFORMATION_SCHEMA' Tables (http://dev.mysql.com/doc/innodb-plugin/1.0/en/innodb-information-schema.html).) To enable these tables, include additional `NAME=LIBRARY' pairs in the value of the `plugin-load' option: [mysqld] ignore-builtin-innodb plugin-load=innodb=ha_innodb_plugin.so ;innodb_trx=ha_innodb_plugin.so ;innodb_locks=ha_innodb_plugin.so ;innodb_lock_waits=ha_innodb_plugin.so ;innodb_cmp=ha_innodb_plugin.so ;innodb_cmp_reset=ha_innodb_plugin.so ;innodb_cmpmem=ha_innodb_plugin.so ;innodb_cmpmem_reset=ha_innodb_plugin.so The `plugin-load' option value as shown here is formatted on multiple lines for display purposes but should be written in `my.cnf' using a single line without spaces in the option value. On Windows, substitute `.dll' for each instance of the `.so' extension. After the server starts, verify that `InnoDB Plugin' has been loaded by using the *Note `SHOW PLUGINS': show-plugins. statement. For example, if you have loaded the storage engine and the `INFORMATION_SCHEMA' tables, the output should include lines similar to these: mysql> SHOW PLUGINS; +---------------------+--------+--------------------+... | Name | Status | Type |... +---------------------+--------+--------------------+... ... | InnoDB | ACTIVE | STORAGE ENGINE |... | INNODB_TRX | ACTIVE | INFORMATION SCHEMA |... | INNODB_LOCKS | ACTIVE | INFORMATION SCHEMA |... | INNODB_LOCK_WAITS | ACTIVE | INFORMATION SCHEMA |... | INNODB_CMP | ACTIVE | INFORMATION SCHEMA |... | INNODB_CMP_RESET | ACTIVE | INFORMATION SCHEMA |... | INNODB_CMPMEM | ACTIVE | INFORMATION SCHEMA |... | INNODB_CMPMEM_RESET | ACTIVE | INFORMATION SCHEMA |... +---------------------+--------+--------------------+... An alternative to using the `plugin-load' option at server startup is to use the *Note `INSTALL PLUGIN': install-plugin. statement at runtime. First start the server with the `ignore-builtin-innodb' option to disable the built-in version of `InnoDB': [mysqld] ignore-builtin-innodb Then issue an *Note `INSTALL PLUGIN': install-plugin. statement for each plugin that you want to load: mysql> INSTALL PLUGIN InnoDB SONAME 'ha_innodb_plugin.so'; mysql> INSTALL PLUGIN INNODB_TRX SONAME 'ha_innodb_plugin.so'; mysql> INSTALL PLUGIN INNODB_LOCKS SONAME 'ha_innodb_plugin.so'; ... *Note `INSTALL PLUGIN': install-plugin. need be issued only once for each plugin. Installed plugins will be loaded automatically on subsequent server restarts. If you build MySQL from a source distribution, `InnoDB Plugin' is one of the storage engines that is built by default. Build MySQL the way you normally do; for example, by using the instructions at *Note source-installation::. After the build completes, you should find the plugin shared object file under the `storage/innodb_plugin' directory, and `make install' should install it in the plugin directory. Configure MySQL to use `InnoDB Plugin' as described earlier for binary distributions. If you use `gcc', `InnoDB Plugin' cannot be compiled with `gcc' 3.x; you must use `gcc' 4.x instead. *Note*: In MySQL 5.5, the `InnoDB Plugin' is also included, but it becomes the built-in version of `InnoDB' in MySQL Server, replacing the version previously included as the built-in `InnoDB' engine. This means that if you use `InnoDB Plugin' in MySQL 5.1 using the instructions just given, you will need to remove `ignore-builtin-innodb' and `plugin-load' from your startup options after an upgrade to MySQL 5.5 or the server will fail to start.  File: manual.info, Node: innodb-multiple-tablespaces, Next: innodb-raw-devices, Prev: replacing-builtin-innodb, Up: innodb-configuration 14.6.2.2 Using Per-Table Tablespaces .................................... You can store each `InnoDB' table and its indexes in its own file. This feature is called `multiple tablespaces' because in effect each table has its own tablespace. Using multiple tablespaces can be beneficial to users who want to move specific tables to separate physical disks or who wish to restore backups of single tables quickly without interrupting the use of other `InnoDB' tables. To enable multiple tablespaces, start the server with the `--innodb_file_per_table' option. For example, add a line to the `[mysqld]' section of `my.cnf': [mysqld] innodb_file_per_table With multiple tablespaces enabled, `InnoDB' stores each newly created table into its own `TBL_NAME.ibd' file in the database directory where the table belongs. This is similar to what the `MyISAM' storage engine does, but `MyISAM' divides the table into a `TBL_NAME.MYD' data file and an `TBL_NAME.MYI' index file. For `InnoDB', the data and the indexes are stored together in the `.ibd' file. The `TBL_NAME.frm' file is still created as usual. You cannot freely move `.ibd' files between database directories as you can with `MyISAM' table files. This is because the table definition that is stored in the `InnoDB' shared tablespace includes the database name, and because `InnoDB' must preserve the consistency of transaction IDs and log sequence numbers. If you remove the `innodb_file_per_table' line from `my.cnf' and restart the server, `InnoDB' creates tables inside the shared tablespace files again. The `--innodb_file_per_table' option affects only table creation, not access to existing tables. If you start the server with this option, new tables are created using `.ibd' files, but you can still access tables that exist in the shared tablespace. If you start the server without this option, new tables are created in the shared tablespace, but you can still access any tables that were created using multiple tablespaces. *Note*: `InnoDB' always needs the shared tablespace because it puts its internal data dictionary and undo logs there. The `.ibd' files are not sufficient for `InnoDB' to operate. To move an `.ibd' file and the associated table from one database to another, use a *Note `RENAME TABLE': rename-table. statement: RENAME TABLE DB1.TBL_NAME TO DB2.TBL_NAME; If you have a `clean' backup of an `.ibd' file, you can restore it to the MySQL installation from which it originated as follows: 1. Issue this *Note `ALTER TABLE': alter-table. statement to delete the current `.ibd' file: ALTER TABLE TBL_NAME DISCARD TABLESPACE; 2. Copy the backup `.ibd' file to the proper database directory. 3. Issue this *Note `ALTER TABLE': alter-table. statement to tell `InnoDB' to use the new `.ibd' file for the table: ALTER TABLE TBL_NAME IMPORT TABLESPACE; In this context, a `clean' `.ibd' file backup is one for which the following requirements are satisfied: * There are no uncommitted modifications by transactions in the `.ibd' file. * There are no unmerged insert buffer entries in the `.ibd' file. * Purge has removed all delete-marked index records from the `.ibd' file. * *Note `mysqld': mysqld. has flushed all modified pages of the `.ibd' file from the buffer pool to the file. You can make a clean backup `.ibd' file using the following method: 1. Stop all activity from the *Note `mysqld': mysqld. server and commit all transactions. 2. Wait until *Note `SHOW ENGINE INNODB STATUS': show-engine. shows that there are no active transactions in the database, and the main thread status of `InnoDB' is `Waiting for server activity'. Then you can make a copy of the `.ibd' file. Another method for making a clean copy of an `.ibd' file is to use the commercial `InnoDB Hot Backup' tool: 1. Use `InnoDB Hot Backup' to back up the `InnoDB' installation. 2. Start a second *Note `mysqld': mysqld. server on the backup and let it clean up the `.ibd' files in the backup.  File: manual.info, Node: innodb-raw-devices, Next: innodb-init, Prev: innodb-multiple-tablespaces, Up: innodb-configuration 14.6.2.3 Using Raw Devices for the Shared Tablespace .................................................... You can use raw disk partitions as data files in the shared tablespace. By using a raw disk, you can perform nonbuffered I/O on Windows and on some Unix systems without file system overhead. This may improve performance, but you are advised to perform tests with and without raw partitions to verify whether this is actually so on your system. When you create a new data file, put the keyword `newraw' immediately after the data file size in `innodb_data_file_path'. The partition must be at least as large as the size that you specify. Note that 1MB in `InnoDB' is 1024 x 1024 bytes, whereas 1MB in disk specifications usually means 1,000,000 bytes. [mysqld] innodb_data_home_dir= innodb_data_file_path=/dev/hdd1:3Gnewraw;/dev/hdd2:2Gnewraw The next time you start the server, `InnoDB' notices the `newraw' keyword and initializes the new partition. However, do not create or change any `InnoDB' tables yet. Otherwise, when you next restart the server, `InnoDB' reinitializes the partition and your changes are lost. (As a safety measure `InnoDB' prevents users from modifying data when any partition with `newraw' is specified.) After `InnoDB' has initialized the new partition, stop the server, change `newraw' in the data file specification to `raw': [mysqld] innodb_data_home_dir= innodb_data_file_path=/dev/hdd1:3Graw;/dev/hdd2:2Graw Then restart the server and `InnoDB' permits changes to be made. On Windows, you can allocate a disk partition as a data file like this: [mysqld] innodb_data_home_dir= innodb_data_file_path=//./D::10Gnewraw The `//./' corresponds to the Windows syntax of `\\.\' for accessing physical drives. When you use a raw disk partition, be sure that it has permissions that enable read and write access by the account used for running the MySQL server. For example, if you run the server as the `mysql' user, the partition must permit read and write access to `mysql'. If you run the server with the `--memlock' option, the server must be run as `root', so the partition must permit access to `root'.  File: manual.info, Node: innodb-init, Next: error-creating-innodb, Prev: innodb-raw-devices, Up: innodb-configuration 14.6.2.4 Creating the `InnoDB' Tablespace ......................................... Suppose that you have installed MySQL and have edited your option file so that it contains the necessary `InnoDB' configuration parameters. Before starting MySQL, verify that the directories you have specified for `InnoDB' data files and log files exist and that the MySQL server has access rights to those directories. `InnoDB' does not create directories, only files. Check also that you have enough disk space for the data and log files. It is best to run the MySQL server *Note `mysqld': mysqld. from the command prompt when you first start the server with `InnoDB' enabled, not from *Note `mysqld_safe': mysqld-safe. or as a Windows service. When you run from a command prompt you see what *Note `mysqld': mysqld. prints and what is happening. On Unix, just invoke *Note `mysqld': mysqld. On Windows, start *Note `mysqld': mysqld. with the `--console' option to direct the output to the console window. When you start the MySQL server after initially configuring `InnoDB' in your option file, `InnoDB' creates your data files and log files, and prints something like this: InnoDB: The first specified datafile /home/heikki/data/ibdata1 did not exist: InnoDB: a new database to be created! InnoDB: Setting file /home/heikki/data/ibdata1 size to 134217728 InnoDB: Database physically writes the file full: wait... InnoDB: datafile /home/heikki/data/ibdata2 did not exist: new to be created InnoDB: Setting file /home/heikki/data/ibdata2 size to 262144000 InnoDB: Database physically writes the file full: wait... InnoDB: Log file /home/heikki/data/logs/ib_logfile0 did not exist: new to be created InnoDB: Setting log file /home/heikki/data/logs/ib_logfile0 size to 5242880 InnoDB: Log file /home/heikki/data/logs/ib_logfile1 did not exist: new to be created InnoDB: Setting log file /home/heikki/data/logs/ib_logfile1 size to 5242880 InnoDB: Doublewrite buffer not found: creating new InnoDB: Doublewrite buffer created InnoDB: Creating foreign key constraint system tables InnoDB: Foreign key constraint system tables created InnoDB: Started mysqld: ready for connections At this point `InnoDB' has initialized its tablespace and log files. You can connect to the MySQL server with the usual MySQL client programs like *Note `mysql': mysql. When you shut down the MySQL server with *Note `mysqladmin shutdown': mysqladmin, the output is like this: 010321 18:33:34 mysqld: Normal shutdown 010321 18:33:34 mysqld: Shutdown Complete InnoDB: Starting shutdown... InnoDB: Shutdown completed You can look at the data file and log directories and you see the files created there. When MySQL is started again, the data files and log files have been created already, so the output is much briefer: InnoDB: Started mysqld: ready for connections If you add the `innodb_file_per_table' option to `my.cnf', `InnoDB' stores each table in its own `.ibd' file in the same MySQL database directory where the `.frm' file is created. See *Note innodb-multiple-tablespaces::.  File: manual.info, Node: error-creating-innodb, Prev: innodb-init, Up: innodb-configuration 14.6.2.5 Dealing with `InnoDB' Initialization Problems ...................................................... If `InnoDB' prints an operating system error during a file operation, usually the problem has one of the following causes: * You did not create the `InnoDB' data file directory or the `InnoDB' log directory. * *Note `mysqld': mysqld. does not have access rights to create files in those directories. * *Note `mysqld': mysqld. cannot read the proper `my.cnf' or `my.ini' option file, and consequently does not see the options that you specified. * The disk is full or a disk quota is exceeded. * You have created a subdirectory whose name is equal to a data file that you specified, so the name cannot be used as a file name. * There is a syntax error in the `innodb_data_home_dir' or `innodb_data_file_path' value. If something goes wrong when `InnoDB' attempts to initialize its tablespace or its log files, delete all files created by `InnoDB'. This means all `ibdata' files and all `ib_logfile' files. In case you have already created some `InnoDB' tables, delete the corresponding `.frm' files for these tables (and any `.ibd' files if you are using multiple tablespaces) from the MySQL database directories as well. Then you can try the `InnoDB' database creation again. It is best to start the MySQL server from a command prompt so that you see what is happening.  File: manual.info, Node: innodb-parameters, Next: using-innodb-tables, Prev: innodb-configuration, Up: innodb-storage-engine 14.6.3 `InnoDB' Startup Options and System Variables ---------------------------------------------------- This section describes the `InnoDB'-related command options and system variables. System variables that are true or false can be enabled at server startup by naming them, or disabled by using a `--skip' prefix. For example, to enable or disable `InnoDB' checksums, you can use `--innodb_checksums' or `--skip-innodb_checksums' on the command line, or `innodb_checksums' or `skip-innodb_checksums' in an option file. System variables that take a numeric value can be specified as `--VAR_NAME=VALUE' on the command line or as `VAR_NAME=VALUE' in option files. For more information on specifying options and system variables, see *Note program-options::. Many of the system variables can be changed at runtime (see *Note dynamic-system-variables::). *`InnoDB' Option/Variable Reference* Name Cmd-Line Option file System Var Status Var Var Scope Dynamic Com_show_ndb_status Yes Both No foreign_key_checks Yes Session Yes have_innodb Yes Global No ignore-builtin-innodbYes Yes Global No - _Variable_: Yes Global No ignore_builtin_innodb innodb Yes Yes innodb_adaptive_flushingYes Yes Yes Global Yes innodb_adaptive_hash_indexYes Yes Yes Global No innodb_additional_mem_pool_sizeYes Yes Yes Global No innodb_autoextend_incrementYes Yes Yes Global Yes innodb_autoinc_lock_modeYes Yes Yes Global No innodb_buffer_pool_awe_mem_mbYes Yes Yes Global No Innodb_buffer_pool_pages_data Yes Global No Innodb_buffer_pool_pages_dirty Yes Global No Innodb_buffer_pool_pages_flushed Yes Global No Innodb_buffer_pool_pages_free Yes Global No Innodb_buffer_pool_pages_latched Yes Global No Innodb_buffer_pool_pages_misc Yes Global No Innodb_buffer_pool_pages_total Yes Global No Innodb_buffer_pool_read_ahead Yes Global No Innodb_buffer_pool_read_ahead_evicted Yes Global No Innodb_buffer_pool_read_ahead_rnd Yes Global No Innodb_buffer_pool_read_ahead_seq Yes Global No Innodb_buffer_pool_read_requests Yes Global No Innodb_buffer_pool_reads Yes Global No innodb_buffer_pool_sizeYes Yes Yes Global No Innodb_buffer_pool_wait_free Yes Global No Innodb_buffer_pool_write_requests Yes Global No innodb_change_bufferingYes Yes Yes Global Yes innodb_checksumsYes Yes Yes Global No innodb_commit_concurrencyYes Yes Yes Global Yes innodb_concurrency_ticketsYes Yes Yes Global Yes innodb_data_file_pathYes Yes Yes Global No Innodb_data_fsyncs Yes Global No innodb_data_home_dirYes Yes Yes Global No Innodb_data_pending_fsyncs Yes Global No Innodb_data_pending_reads Yes Global No Innodb_data_pending_writes Yes Global No Innodb_data_read Yes Global No Innodb_data_reads Yes Global No Innodb_data_writes Yes Global No Innodb_data_written Yes Global No Innodb_dblwr_pages_written Yes Global No Innodb_dblwr_writes Yes Global No innodb_doublewriteYes Yes Yes Global No innodb_fast_shutdownYes Yes Yes Global Yes innodb_file_formatYes Yes Yes Global Yes innodb_file_format_checkYes Yes Yes Global Yes innodb_file_io_threadsYes Yes Yes Global No innodb_file_per_tableYes Yes Yes Global No innodb_flush_log_at_trx_commitYes Yes Yes Global Yes innodb_flush_methodYes Yes Yes Global No innodb_force_recoveryYes Yes Yes Global No Innodb_have_atomic_builtins Yes Global No innodb_io_capacityYes Yes Yes Global No innodb_lock_wait_timeoutYes Yes Yes Both Yes innodb_locks_unsafe_for_binlogYes Yes Yes Global No innodb_log_arch_dirYes Yes Yes Global No innodb_log_archiveYes Yes Yes Global No innodb_log_buffer_sizeYes Yes Yes Global No innodb_log_file_sizeYes Yes Yes Global No innodb_log_files_in_groupYes Yes Yes Global No innodb_log_group_home_dirYes Yes Yes Global No Innodb_log_waits Yes Global No Innodb_log_write_requests Yes Global No Innodb_log_writes Yes Global No innodb_max_dirty_pages_pctYes Yes Yes Global Yes innodb_max_purge_lagYes Yes Yes Global Yes innodb_mirrored_log_groupsYes Yes Yes Global No innodb_old_blocks_pctYes Yes Yes Global Yes innodb_old_blocks_timeYes Yes Yes Global Yes innodb_open_filesYes Yes Yes Global No Innodb_os_log_fsyncs Yes Global No Innodb_os_log_pending_fsyncs Yes Global No Innodb_os_log_pending_writes Yes Global No Innodb_os_log_written Yes Global No Innodb_page_size Yes Global No Innodb_pages_created Yes Global No Innodb_pages_read Yes Global No Innodb_pages_written Yes Global No innodb_read_ahead_thresholdYes Yes Yes Global Yes innodb_read_io_threadsYes Yes Yes Global No innodb_replication_delayYes Yes Yes Global Yes innodb_rollback_on_timeoutYes Yes Yes Global No Innodb_row_lock_current_waits Yes Global No Innodb_row_lock_time Yes Global No Innodb_row_lock_time_avg Yes Global No Innodb_row_lock_time_max Yes Global No Innodb_row_lock_waits Yes Global No Innodb_rows_deleted Yes Global No Innodb_rows_inserted Yes Global No Innodb_rows_read Yes Global No Innodb_rows_updated Yes Global No innodb_spin_wait_delayYes Yes Yes Global Yes innodb_stats_on_metadataYes Yes Yes Global Yes innodb_stats_sample_pagesYes Yes Yes Global Yes innodb-status-fileYes Yes innodb_strict_modeYes Yes Yes Both Yes innodb_support_xaYes Yes Yes Both Yes innodb_sync_spin_loopsYes Yes Yes Global Yes innodb_table_locksYes Yes Yes Both Yes innodb_thread_concurrencyYes Yes Yes Global Yes innodb_thread_sleep_delayYes Yes Yes Global Yes innodb_use_legacy_cardinality_algorithmYes Yes Yes Global Yes innodb_use_sys_mallocYes Yes Yes Global No innodb_version Yes Global No innodb_write_io_threadsYes Yes Yes Global No timed_mutexes Yes Yes Yes Global Yes unique_checks Yes Session Yes * `InnoDB' Command Options * * `--ignore-builtin-innodb' Options for ignore-builtin-innodb *Version Introduced* 5.1.33 *Command-Line `--ignore-builtin-innodb' Format* *Option-File Format* `ignore-builtin-innodb' *Option Sets Yes, Variable* `ignore_builtin_innodb' *Variable Name* `ignore-builtin-innodb' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `boolean' This option causes the server to behave as if the built-in `InnoDB' is not present, which enables `InnoDB Plugin' to be used instead. See *Note replacing-builtin-innodb::. If this option is given but `InnoDB Plugin' is not used in place of the built-in `InnoDB', it has the following effects: * Other *Note `InnoDB': innodb-storage-engine. options (including `--innodb' and `--skip-innodb') will not be recognized and should not be used. * The server will not start if the default storage engine is set to *Note `InnoDB': innodb-storage-engine. Use `--default-storage-engine' to set the default to some other engine if necessary. * *Note `InnoDB': innodb-storage-engine. will not appear in the output of *Note `SHOW ENGINES': show-engines. This option was added in MySQL 5.1.33. * `--innodb[=VALUE]' Controls loading of the `InnoDB' storage engine, if the server was compiled with `InnoDB' support. As of MySQL 5.1.36, this option has a tristate format, with possible values of `OFF', `ON', or `FORCE'. Before MySQL 5.1.36, this is a boolean option. See *Note server-plugin-loading::. To disable `InnoDB', use `--innodb=OFF' or `--skip-innodb'. In this case, the server will not start if the default storage engine is set to *Note `InnoDB': innodb-storage-engine. Use `--default-storage-engine' to set the default to some other engine if necessary. * `--innodb-status-file' Controls whether `InnoDB' creates a file named `innodb_status.' in the MySQL data directory. If enabled, `InnoDB' periodically writes the output of *Note `SHOW ENGINE INNODB STATUS': show-engine. to this file. By default, the file is not created. To create it, start *Note `mysqld': mysqld. with the `--innodb-status-file=1' option. The file is deleted during normal shutdown. * `--skip-innodb' Disable the `InnoDB' storage engine. See the description of `--innodb'. * `InnoDB' System Variables * * `ignore_builtin_innodb' Whether the server was started with the `--ignore-builtin-innodb' option, which causes the server to behave as if the built-in `InnoDB' is not present. For more information, see the description of `--ignore-builtin-innodb' under ``InnoDB' Command Options' earlier in this section. This variable was added in MySQL 5.1.33. * `innodb_adaptive_flushing' Options for innodb_adaptive_flushing *Version Introduced* 5.1.38 *Command-Line `--innodb_adaptive_flushing=#' Format* *Option-File Format* `innodb_adaptive_flushing' *Option Sets Yes, Variable* `innodb_adaptive_flushing' *Variable Name* `innodb_adaptive_flushing' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `boolean' *Default* `ON' (`InnoDB Plugin' only) `InnoDB Plugin' 1.0.4 and up uses a heuristic to determine when to flush dirty pages in the buffer cache. This heuristic is designed to avoid bursts of I/O activity and is used when `innodb_adaptive_flushing' is enabled (which is the default). * `innodb_adaptive_hash_index' Options for innodb_adaptive_hash_index *Version Introduced* 5.1.24 *Command-Line `--innodb_adaptive_hash_index=#' Format* *Option-File Format* `innodb_adaptive_hash_index' *Option Sets Yes, Variable* `innodb_adaptive_hash_index' *Variable Name* `innodb_adaptive_hash_index' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `boolean' *Default* `ON' Whether InnoDB adaptive hash indexes are enabled or disabled (see *Note innodb-adaptive-hash::). This variable is enabled by default. Use `--skip-innodb_adaptive_hash_index' at server startup to disable it. This variable was added in MySQL 5.1.24. * `innodb_additional_mem_pool_size' Options for innodb_additional_mem_pool_size *Command-Line `--innodb_additional_mem_pool_size=#' Format* *Option-File Format* `innodb_additional_mem_pool_size' *Option Sets Yes, Variable* `innodb_additional_mem_pool_size' *Variable Name* `innodb_additional_mem_pool_size' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `numeric' *Default* `1048576' *Range* `524288-4294967295' The size in bytes of a memory pool `InnoDB' uses to store data dictionary information and other internal data structures. The more tables you have in your application, the more memory you need to allocate here. If `InnoDB' runs out of memory in this pool, it starts to allocate memory from the operating system and writes warning messages to the MySQL error log. The default value is 1MB for the built-in *Note `InnoDB': innodb-storage-engine, 8MB for `InnoDB Plugin'. * `innodb_autoextend_increment' Options for innodb_autoextend_increment *Command-Line `--innodb_autoextend_increment=#' Format* *Option-File Format* `innodb_autoextend_increment' *Option Sets Yes, Variable* `innodb_autoextend_increment' *Variable Name* `innodb_autoextend_increment' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `numeric' *Default* `8' *Range* `1-1000' The increment size (in MB) for extending the size of an auto-extending shared tablespace file when it becomes full. The default value is 8. This variable does not affect the per-table tablespace files that are created if you use `innodb_file_per_table=1'. Those files are auto-extending regardless of the value of `innodb_autoextend_increment'. The initial extensions are by small amounts, after which extensions occur in increments of 4MB. * `innodb_buffer_pool_awe_mem_mb' Options for innodb_buffer_pool_awe_mem_mb *Version Removed* 5.1.13 *Command-Line `--innodb_buffer_pool_awe_mem_mb=#' Format* *Option-File Format* `innodb_buffer_pool_awe_mem_mb' *Option Sets Yes, Variable* `innodb_buffer_pool_awe_mem_mb' *Variable Name* `innodb_buffer_pool_awe_mem_mb' *Variable Scope* Global *Dynamic Variable* No *Platform Specific* windows *Permitted Values * *Type* (windows) `numeric' *Default* `0' *Range* `0-63000' The size of the buffer pool (in MB), if it is placed in the AWE memory. If it is greater than 0, `innodb_buffer_pool_size' is the window in the 32-bit address space of *Note `mysqld': mysqld. where `InnoDB' maps that AWE memory. A good value for `innodb_buffer_pool_size' is 500MB. The maximum possible value is 63000. To take advantage of AWE memory, you will need to recompile MySQL yourself. The current project settings needed for doing this can be found in the `storage/innobase/os/os0proc.c' source file. This variable was removed in MySQL 5.1.13. Before that, it is relevant only in 32-bit Windows. If your 32-bit Windows operating system supports more than 4GB memory, using so-called `Address Windowing Extensions,' you can allocate the `InnoDB' buffer pool into the AWE physical memory using this variable. * `innodb_autoinc_lock_mode' Options for innodb_autoinc_lock_mode *Version Introduced* 5.1.22 *Command-Line `--innodb_autoinc_lock_mode=#' Format* *Option-File Format* `innodb_autoinc_lock_mode' *Option Sets Yes, Variable* `innodb_autoinc_lock_mode' *Variable Name* `innodb_autoinc_lock_mode' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `numeric' *Default* `1' *Valid Values* `0' `1' `2' The locking mode to use for generating auto-increment values. The permissible values are 0, 1, or 2, for `traditional', `consecutive', or `interleaved' lock mode, respectively. *Note innodb-auto-increment-handling::, describes the characteristics of these modes. This variable was added in MySQL 5.1.22 with a default of 1 (`consecutive' lock mode). Before 5.1.22, `InnoDB' uses `traditional' lock mode. * `innodb_buffer_pool_size' Options for innodb_buffer_pool_size *Command-Line `--innodb_buffer_pool_size=#' Format* *Option-File Format* `innodb_buffer_pool_size' *Option Sets Yes, Variable* `innodb_buffer_pool_size' *Variable Name* `innodb_buffer_pool_size' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Platform Bit Size* `32' *Type* `numeric' *Default* `134217728' *Range* `1048576-2**32-1' *Permitted Values * *Platform Bit Size* `64' *Type* `numeric' *Default* `134217728' *Range* `1048576-2**64-1' The size in bytes of the memory buffer `InnoDB' uses to cache data and indexes of its tables. The default value is 128MB, increased from a historical default of 8MB. The maximum value depends on the CPU architecture, 32-bit or 64-bit. For 32-bit systems, the CPU architecture and operating system sometimes impose a lower practical maximum size. The larger you set this value, the less disk I/O is needed to access data in tables. On a dedicated database server, you may set this to up to 80% of the machine physical memory size. Be prepared to scale back this value if these other issues occur: * Competition for physical memory might cause paging in the operating system. * InnoDB reserves additional memory for buffers and control structures, so that the total allocated space is approximately 10% greater than the specified size. * The address space must be contiguous, which can be an issue on Windows systems with DLLs that load at specific addresses. * The time to initialize the buffer pool is roughly proportional to its size. On large installations, this initialization time may be significant. For example, on a modern Linux x86_64 server, initialization of a 10GB buffer pool takes approximately 6 seconds. See *Note innodb-buffer-pool::. * `innodb_change_buffering' Options for innodb_change_buffering *Version Introduced* 5.1.38 *Command-Line `--innodb_change_buffering=#' Format* *Option-File Format* `innodb_change_buffering' *Option Sets Yes, Variable* `innodb_change_buffering' *Variable Name* `innodb_change_buffering' *Variable Scope* Global *Dynamic Variable* Yes (`InnoDB Plugin' only) Whether *Note `InnoDB': innodb-storage-engine. performs insert buffering. The permitted values `none' (do not buffer any operations) and `inserts' (buffer insert operations). The default is `inserts'. For details, see Controlling InnoDB Insert Buffering (http://dev.mysql.com/doc/innodb-plugin/1.0/en/innodb-performance-change_buffering.html). * `innodb_checksums' Options for innodb_checksums *Command-Line `--innodb_checksums' Format* *Option-File Format* `innodb_checksums' *Option Sets Yes, Variable* `innodb_checksums' *Variable Name* `innodb_checksums' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `boolean' *Default* `ON' `InnoDB' can use checksum validation on all pages read from the disk to ensure extra fault tolerance against broken hardware or data files. This validation is enabled by default. However, under some rare circumstances (such as when running benchmarks) this extra safety feature is unneeded and can be disabled with `--skip-innodb-checksums'. * `innodb_commit_concurrency' Options for innodb_commit_concurrency *Command-Line `--innodb_commit_concurrency=#' Format* *Option-File Format* `innodb_commit_concurrency' *Option Sets Yes, Variable* `innodb_commit_concurrency' *Variable Name* `innodb_commit_concurrency' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `numeric' *Default* `0' *Range* `0-1000' The number of threads that can commit at the same time. A value of 0 (the default) permits any number of transactions to commit simultaneously. As of MySQL 5.1.36, the value of `innodb_commit_concurrency' cannot be changed at runtime from zero to nonzero or vice versa. The value can still be changed from one nonzero value to another. * `innodb_concurrency_tickets' Options for innodb_concurrency_tickets *Command-Line `--innodb_concurrency_tickets=#' Format* *Option-File Format* `innodb_concurrency_tickets' *Option Sets Yes, Variable* `innodb_concurrency_tickets' *Variable Name* `innodb_concurrency_tickets' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `numeric' *Default* `500' *Range* `1-4294967295' The number of threads that can enter `InnoDB' concurrently is determined by the `innodb_thread_concurrency' variable. A thread is placed in a queue when it tries to enter `InnoDB' if the number of threads has already reached the concurrency limit. When a thread is permitted to enter `InnoDB', it is given a number of `free tickets' equal to the value of `innodb_concurrency_tickets', and the thread can enter and leave `InnoDB' freely until it has used up its tickets. After that point, the thread again becomes subject to the concurrency check (and possible queuing) the next time it tries to enter `InnoDB'. The default value is 500. * `innodb_data_file_path' Options for innodb_data_file_path *Command-Line `--innodb_data_file_path=name' Format* *Option-File Format* `innodb_data_file_path' *Variable Name* `innodb_data_file_path' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `file name' The paths to individual data files and their sizes. The full directory path to each data file is formed by concatenating `innodb_data_home_dir' to each path specified here. The file sizes are specified in KB, MB, or GB (1024MB) by appending `K', `M', or `G' to the size value. The sum of the sizes of the files must be at least 10MB. If you do not specify `innodb_data_file_path', the default behavior is to create a single 10MB auto-extending data file named `ibdata1'. The size limit of individual files is determined by your operating system. You can set the file size to more than 4GB on those operating systems that support big files. You can also use raw disk partitions as data files. For detailed information on configuring `InnoDB' tablespace files, see *Note innodb-configuration::. * `innodb_data_home_dir' Options for innodb_data_home_dir *Command-Line `--innodb_data_home_dir=path' Format* *Option-File Format* `innodb_data_home_dir' *Option Sets Yes, Variable* `innodb_data_home_dir' *Variable Name* `innodb_data_home_dir' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `file name' The common part of the directory path for all `InnoDB' data files in the shared tablespace. This setting does not affect the location of per-file tablespaces when `innodb_file_per_table' is enabled. The default value is the MySQL data directory. If you specify the value as an empty string, you can use absolute file paths in `innodb_data_file_path'. * `innodb_doublewrite' Options for innodb_doublewrite *Command-Line `--innodb-doublewrite' Format* *Option-File Format* `innodb_doublewrite' *Option Sets Yes, Variable* `innodb_doublewrite' *Variable Name* `innodb_doublewrite' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `boolean' If this variable is enabled (the default), `InnoDB' stores all data twice, first to the doublewrite buffer, and then to the actual data files. This variable can be turned off with `--skip-innodb_doublewrite' for benchmarks or cases when top performance is needed rather than concern for data integrity or possible failures. * `innodb_fast_shutdown' Options for innodb_fast_shutdown *Command-Line `--innodb_fast_shutdown[=#]' Format* *Option-File Format* `innodb_fast_shutdown' *Option Sets Yes, Variable* `innodb_fast_shutdown' *Variable Name* `innodb_fast_shutdown' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `numeric' *Default* `1' *Valid Values* `0' `1' `2' The `InnoDB' shutdown mode. By default, the value is 1, which causes a `fast' shutdown (the normal type of shutdown). If the value is 0, `InnoDB' does a full purge and an insert buffer merge before a shutdown. These operations can take minutes, or even hours in extreme cases. If the value is 1, `InnoDB' skips these operations at shutdown. If the value is 2, `InnoDB' will just flush its logs and then shut down cold, as if MySQL had crashed; no committed transaction will be lost, but crash recovery will be done at the next startup. A value of 2 cannot be used on NetWare. * `innodb_file_format' Options for innodb_file_format *Version Introduced* 5.1.38 *Command-Line `--innodb_file_format=#' Format* *Option-File Format* `innodb_file_format' *Option Sets Yes, Variable* `innodb_file_format' *Variable Name* `innodb_file_format' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values (>= 5.1.38)* *Type* `string' *Default* `Antelope' (`InnoDB Plugin' only) The file format to use for new *Note `InnoDB': innodb-storage-engine. tables. Currently `Antelope' and `Barracuda' are supported. This applies only for tables that have their own tablespace, so for it to have an effect `innodb_file_per_table' must be enabled. * `innodb_file_format_check' Options for innodb_file_format_check *Version Introduced* 5.1.38 *Command-Line `--innodb_file_format_check=#' Format* *Option-File Format* `innodb_file_format_check' *Option Sets Yes, Variable* `innodb_file_format_check' *Variable Name* `innodb_file_format_check' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values (<= 5.1.41)* *Type* `string' *Default* `Antelope' *Permitted Values (>= 5.1.42)* *Type* `string' *Default* `Barracuda' (`InnoDB Plugin' only) This variable can be set to 1 or 0 at server startup to enable or disable whether `InnoDB' checks the file format tag in the shared tablespace (for example, `Antelope' or `Barracuda'). If the tag is checked and is higher than that supported by the current version of `InnoDB', an error occurs and `InnoDB' does not start. If the tag is not higher, `InnoDB' sets the value of `innodb_file_format_check' to the file format tag, which is the value seen at runtime. * `innodb_file_io_threads' Options for innodb_file_io_threads *Command-Line `--innodb_file_io_threads=#' Format* *Option-File Format* `innodb_file_io_threads' *Option Sets Yes, Variable* `innodb_file_io_threads' *Variable Name* `innodb_file_io_threads' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `numeric' *Default* `4' *Range* `4-64' The number of file I/O threads in `InnoDB'. Normally, this should be left at the default value of 4, but disk I/O on Windows may benefit from a larger number. On Unix, increasing the number has no effect; `InnoDB' always uses the default value. With `InnoDB Plugin', this variable is unused. Use `innodb_read_io_threads' and `innodb_write_io_threads' instead. * `innodb_file_per_table' Options for innodb_file_per_table *Command-Line `--innodb_file_per_table' Format* *Option-File Format* `innodb_file_per_table' *Variable Name* `innodb_file_per_table' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `boolean' *Default* `OFF' If `innodb_file_per_table' is disabled (the default), `InnoDB' creates tables in the shared tablespace. If `innodb_file_per_table' is enabled, `InnoDB' creates each new table using its own `.ibd' file for storing data and indexes, rather than in the shared tablespace. See *Note innodb-multiple-tablespaces::. * `innodb_flush_log_at_trx_commit' Options for innodb_flush_log_at_trx_commit *Command-Line `--innodb_flush_log_at_trx_commit[=#]' Format* *Option-File Format* `innodb_flush_log_at_trx_commit' *Option Sets Yes, Variable* `innodb_flush_log_at_trx_commit' *Variable Name* `innodb_flush_log_at_trx_commit' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `numeric' *Default* `1' *Valid Values* `0' `1' `2' If the value of `innodb_flush_log_at_trx_commit' is 0, the log buffer is written out to the log file once per second and the flush to disk operation is performed on the log file, but nothing is done at a transaction commit. When the value is 1 (the default), the log buffer is written out to the log file at each transaction commit and the flush to disk operation is performed on the log file. When the value is 2, the log buffer is written out to the file at each commit, but the flush to disk operation is not performed on it. However, the flushing on the log file takes place once per second also when the value is 2. Note that the once-per-second flushing is not 100% guaranteed to happen every second, due to process scheduling issues. The default value of 1 is the value required for ACID compliance. You can achieve better performance by setting the value different from 1, but then you can lose at most one second worth of transactions in a crash. With a value of 0, any *Note `mysqld': mysqld. process crash can erase the last second of transactions. With a value of 2, then only an operating system crash or a power outage can erase the last second of transactions. However, `InnoDB''s crash recovery is not affected and thus crash recovery does work regardless of the value. For the greatest possible durability and consistency in a replication setup using `InnoDB' with transactions, use `innodb_flush_log_at_trx_commit = 1' and `sync_binlog = 1' in your master server `my.cnf' file. *Caution*: Many operating systems and some disk hardware fool the flush-to-disk operation. They may tell *Note `mysqld': mysqld. that the flush has taken place, even though it has not. Then the durability of transactions is not guaranteed even with the setting 1, and in the worst case a power outage can even corrupt the `InnoDB' database. Using a battery-backed disk cache in the SCSI disk controller or in the disk itself speeds up file flushes, and makes the operation safer. You can also try using the Unix command `hdparm' to disable the caching of disk writes in hardware caches, or use some other command specific to the hardware vendor. * `innodb_flush_method' Options for innodb_flush_method *Command-Line `--innodb_flush_method=name' Format* *Option-File Format* `innodb_flush_method' *Option Sets Yes, Variable* `innodb_flush_method' *Variable Name* `innodb_flush_method' *Variable Scope* Global *Dynamic Variable* No *Permitted Values (<= 5.1.23)* *Type* (linux) `enumeration' *Default* `fdatasync' *Valid Values* `fdatasync' `O_DSYNC' `O_DIRECT' *Permitted Values (<= 5.1.23)* *Type* (hpux) `enumeration' *Default* `fdatasync' *Valid Values* `fdatasync' `O_DSYNC' `O_DIRECT' *Permitted Values (<= 5.1.23)* *Type* (solaris) `enumeration' *Default* `fdatasync' *Valid Values* `fdatasync' `O_DSYNC' `O_DIRECT' *Permitted Values (>= 5.1.24)* *Type* (solaris) `enumeration' *Default* `fdatasync' *Valid Values* `O_DSYNC' `O_DIRECT' *Permitted Values (>= 5.1.24)* *Type* (hpux) `enumeration' *Default* `fdatasync' *Valid Values* `O_DSYNC' `O_DIRECT' *Permitted Values (>= 5.1.24)* *Type* (linux) `enumeration' *Default* `fdatasync' *Valid Values* `O_DSYNC' `O_DIRECT' By default, `InnoDB' uses `fsync()' to flush both the data and log files. If `innodb_flush_method' option is set to `O_DSYNC', `InnoDB' uses `O_SYNC' to open and flush the log files, and `fsync()' to flush the data files. If `O_DIRECT' is specified (available on some GNU/Linux versions, FreeBSD, and Solaris), `InnoDB' uses `O_DIRECT' (or `directio()' on Solaris) to open the data files, and uses `fsync()' to flush both the data and log files. Note that `InnoDB' uses `fsync()' instead of `fdatasync()', and it does not use `O_DSYNC' by default because there have been problems with it on many varieties of Unix. This variable is relevant only for Unix. On Windows, the flush method is always `async_unbuffered' and cannot be changed. Different values of this variable can have a marked effect on `InnoDB' performance. For example, on some systems where `InnoDB' data and log files are located on a SAN, it has been found that setting `innodb_flush_method' to `O_DIRECT' can degrade performance of simple *Note `SELECT': select. statements by a factor of three. Formerly it was possible to explicitly specify a value of `fdatasync' to obtain the default behavior. This is no longer possible as of MySQL 5.1.24 because it can be confusing that a value of `fdatasync' causes use of `fsync()' rather than `fdatasync()' for flushing. To obtain the default value now, do not set `innodb_flush_method' at startup. * `innodb_force_recovery' Options for innodb_force_recovery *Command-Line `--innodb_force_recovery=#' Format* *Option-File Format* `innodb_force_recovery' *Option Sets Yes, Variable* `innodb_force_recovery' *Variable Name* `innodb_force_recovery' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `enumeration' *Default* `0' *Valid Values* `0' `1' `2' `3' `4' `5' `6' The crash recovery mode. Possible values are from 0 to 6. The meanings of these values are described in *Note forcing-innodb-recovery::. *Warning*: This variable should be set greater than 0 only in an emergency situation when you want to dump your tables from a corrupt database! As a safety measure, `InnoDB' prevents any changes to its data when this variable is greater than 0. * `innodb_io_capacity' Options for innodb_io_capacity *Version Introduced* 5.1.38 *Command-Line `--innodb_io_capacity=#' Format* *Option-File Format* `innodb_io_capacity' *Option Sets Yes, Variable* `innodb_io_capacity' *Variable Name* `innodb_io_capacity' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Platform Bit Size* `32' *Type* `numeric' *Default* `200' *Range* `100-2**32-1' *Permitted Values * *Platform Bit Size* `64' *Type* `numeric' *Default* `200' *Range* `100-2**64-1' (`InnoDB Plugin' only) An upper limit on the I/O activity performed by the `InnoDB' background tasks, such as flushing pages from the buffer pool (http://dev.mysql.com/doc/innodb-plugin/1.0/en/glossary.html#glos_buffer_pool) and merging data from the insert buffer (http://dev.mysql.com/doc/innodb-plugin/1.0/en/glossary.html#glos_insert_buffer). The default value is 200. For busy systems capable of higher I/O rates, you can set a higher value at server startup, to help the server handle the background maintenance work associated with a high rate of row changes. For systems with individual 5400 RPM or 7200 RPM drives, you might lower the value to the former default of `100'. This parameter should be set to approximately the number of I/O operations that the system can perform per second. The Ideally, keep this setting as low as practical, but not so low that these background activities fall behind. If the value is too high, data is removed from the buffer pool and insert buffer too quickly to provide significant benefit from the caching. The value represents an estimated proportion of the I/O operations per second (IOPS) available to older-generation disk drives that could perform about 100 IOPS. The current default of 200 reflects that modern storage devices are capable of much higher I/O rates. In general, you can increase the value as a function of the number of drives used for *Note `InnoDB': innodb-storage-engine. I/O, particularly fast drives capable of high numbers of IOPS. For example, systems that use multiple disks or solid-state disks for *Note `InnoDB': innodb-storage-engine. are likely to benefit from the ability to control this parameter. Although you can specify a very high number, in practice such large values cease to have any benefit; for example, a value of one million would be considered very high. You can set the `innodb_io_capacity' value to any number 100 or greater, and the default value is `200'. You can set the value of this parameter in the MySQL option file (`my.cnf' or `my.ini') or change it dynamically with the `SET GLOBAL' command, which requires the `SUPER' privilege. See Controlling the Master Thread I/O Rate (http://dev.mysql.com/doc/innodb-plugin/1.0/en/innodb-performance-thread_io_rate.html) for more guidelines about this option. For general information about InnoDB I/O performance, see Optimizing `InnoDB' Disk I/O (http://dev.mysql.com/doc/refman/5.5/en/optimizing-innodb-diskio.html). This variable was added in MySQL 5.1.38. * `innodb_lock_wait_timeout' Options for innodb_lock_wait_timeout *Command-Line `--innodb_lock_wait_timeout=#' Format* *Option-File Format* `innodb_lock_wait_timeout' *Option Sets Yes, Variable* `innodb_lock_wait_timeout' *Variable Name* `innodb_lock_wait_timeout' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `numeric' *Default* `50' *Range* `1-1073741824' The timeout in seconds an `InnoDB' transaction may wait for a row lock before giving up. The default value is 50 seconds. A transaction that tries to access a row that is locked by another `InnoDB' transaction will hang for at most this many seconds before issuing the following error: ERROR 1205 (HY000): Lock wait timeout exceeded; try restarting transaction When a lock wait timeout occurs, the current statement is not executed. The current transaction is _not_ rolled back. (To have the entire transaction roll back, start the server with the `--innodb_rollback_on_timeout' option, available as of MySQL 5.1.15. See also *Note innodb-error-handling::.) `innodb_lock_wait_timeout' applies to `InnoDB' row locks only. A MySQL table lock does not happen inside `InnoDB' and this timeout does not apply to waits for table locks. `InnoDB' does detect transaction deadlocks in its own lock table immediately and rolls back one transaction. The lock wait timeout value does not apply to such a wait. For the built-in `InnoDB', this variable can be set only at server startup. For `InnoDB Plugin', it can be set at startup or changed at runtime, and has both global and session values. * `innodb_locks_unsafe_for_binlog' Options for innodb_locks_unsafe_for_binlog *Command-Line `--innodb_locks_unsafe_for_binlog' Format* *Option-File Format* `innodb_locks_unsafe_for_binlog' *Option Sets Yes, Variable* `innodb_locks_unsafe_for_binlog' *Variable Name* `innodb_locks_unsafe_for_binlog' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `boolean' *Default* `OFF' This variable affects how `InnoDB' uses gap locking for searches and index scans. Normally, `InnoDB' uses an algorithm called _next-key locking_ that combines index-row locking with gap locking. `InnoDB' performs row-level locking in such a way that when it searches or scans a table index, it sets shared or exclusive locks on the index records it encounters. Thus, the row-level locks are actually index-record locks. In addition, a next-key lock on an index record also affects the `gap' before that index record. That is, a next-key lock is an index-record lock plus a gap lock on the gap preceding the index record. If one session has a shared or exclusive lock on record `R' in an index, another session cannot insert a new index record in the gap immediately before `R' in the index order. See *Note innodb-record-level-locks::. By default, the value of `innodb_locks_unsafe_for_binlog' is 0 (disabled), which means that gap locking is enabled: `InnoDB' uses next-key locks for searches and index scans. To enable the variable, set it to 1. This causes gap locking to be disabled: `InnoDB' uses only index-record locks for searches and index scans. Enabling `innodb_locks_unsafe_for_binlog' does not disable the use of gap locking for foreign-key constraint checking or duplicate-key checking. The effect of enabling `innodb_locks_unsafe_for_binlog' is similar to but not identical to setting the transaction isolation level to `READ COMMITTED': * Enabling `innodb_locks_unsafe_for_binlog' is a global setting and affects all sessions, whereas the isolation level can be set globally for all sessions, or individually per session. * `innodb_locks_unsafe_for_binlog' can be set only at server startup, whereas the isolation level can be set at startup or changed at runtime. `READ COMMITTED' therefore offers finer and more flexible control than `innodb_locks_unsafe_for_binlog'. For additional details about the effect of isolation level on gap locking, see *Note set-transaction::. Enabling `innodb_locks_unsafe_for_binlog' may cause phantom problems because other sessions can insert new rows into the gaps when gap locking is disabled. Suppose that there is an index on the `id' column of the `child' table and that you want to read and lock all rows from the table having an identifier value larger than 100, with the intention of updating some column in the selected rows later: SELECT * FROM child WHERE id > 100 FOR UPDATE; The query scans the index starting from the first record where `id' is greater than 100. If the locks set on the index records in that range do not lock out inserts made in the gaps, another session can insert a new row into the table. Consequently, if you were to execute the same *Note `SELECT': select. again within the same transaction, you would see a new row in the result set returned by the query. This also means that if new items are added to the database, `InnoDB' does not guarantee serializability. Therefore, if `innodb_locks_unsafe_for_binlog' is enabled, `InnoDB' guarantees at most an isolation level of `READ COMMITTED'. (Conflict serializability is still guaranteed.) For additional information about phantoms, see *Note innodb-next-key-locking::. Enabling `innodb_locks_unsafe_for_binlog' has additional effects: * For *Note `UPDATE': update. or *Note `DELETE': delete. statements, `InnoDB' holds locks only for rows that it updates or deletes. Record locks for nonmatching rows are released after MySQL has evaluated the `WHERE' condition. This greatly reduces the probability of deadlocks, but they can still happen. * For *Note `UPDATE': update. statements, if a row is already locked, `InnoDB' performs a `semi-consistent' read, returning the latest committed version to MySQL so that MySQL can determine whether the row matches the `WHERE' condition of the *Note `UPDATE': update. If the row matches (must be updated), MySQL reads the row again and this time `InnoDB' either locks it or waits for a lock on it. Consider the following example, beginning with this table: CREATE TABLE t (a INT NOT NULL, b INT) ENGINE = InnoDB; INSERT INTO t VALUES (1,2),(2,3),(3,2),(4,3),(5,2); COMMIT; In this case, table has no indexes, so searches and index scans use the hidden clustered index for record locking (see *Note innodb-index-types::). Suppose that one client performs an *Note `UPDATE': update. using these statements: SET autocommit = 0; UPDATE t SET b = 5 WHERE b = 3; Suppose also that a second client performs an *Note `UPDATE': update. by executing these statements following those of the first client: SET autocommit = 0; UPDATE t SET b = 4 WHERE b = 2; As *Note `InnoDB': innodb-storage-engine. executes each *Note `UPDATE': update, it first acquires an exclusive lock for each row, and then determines whether to modify it. If *Note `InnoDB': innodb-storage-engine. does not modify the row and `innodb_locks_unsafe_for_binlog' is enabled, it releases the lock. Otherwise, *Note `InnoDB': innodb-storage-engine. retains the lock until the end of the transaction. This affects transaction processing as follows. If `innodb_locks_unsafe_for_binlog' is disabled, the first *Note `UPDATE': update. acquires x-locks and does not release any of them: x-lock(1,2); retain x-lock x-lock(2,3); update(2,3) to (2,5); retain x-lock x-lock(3,2); retain x-lock x-lock(4,3); update(4,3) to (4,5); retain x-lock x-lock(5,2); retain x-lock The second *Note `UPDATE': update. blocks as soon as it tries to acquire any locks (because first update has retained locks on all rows), and does not proceed until the first *Note `UPDATE': update. commits or rolls back: x-lock(1,2); block and wait for first UPDATE to commit or roll back If `innodb_locks_unsafe_for_binlog' is enabled, the first *Note `UPDATE': update. acquires x-locks and releases those for rows that it does not modify: x-lock(1,2); unlock(1,2) x-lock(2,3); update(2,3) to (2,5); retain x-lock x-lock(3,2); unlock(3,2) x-lock(4,3); update(4,3) to (4,5); retain x-lock x-lock(5,2); unlock(5,2) For the second `UPDATE', `InnoDB' does a `semi-consistent' read, returning the latest committed version of each row to MySQL so that MySQL can determine whether the row matches the `WHERE' condition of the *Note `UPDATE': update.: x-lock(1,2); update(1,2) to (1,4); retain x-lock x-lock(2,3); unlock(2,3) x-lock(3,2); update(3,2) to (3,4); retain x-lock x-lock(4,3); unlock(4,3) x-lock(5,2); update(5,2) to (5,4); retain x-lock Semi-consistent read is available as of MySQL 5.1.5. Before 5.1.5, the second *Note `UPDATE': update. proceeds part way before it blocks. It begins acquiring x-locks, and blocks when it tries to acquire one for a row still locked by first *Note `UPDATE': update. The second *Note `UPDATE': update. does not proceed until the first *Note `UPDATE': update. commits or rolls back: x-lock(1,2); update(1,2) to (1,4); retain x-lock x-lock(2,3); block and wait for first UPDATE to commit or roll back In this case, the second *Note `UPDATE': update. must wait for a commit or rollback of the first *Note `UPDATE': update, even though it affects different rows. The first *Note `UPDATE': update. has an exclusive lock on row (2,3) that it has not released. As the second *Note `UPDATE': update. scans rows, it tries to acquire an exclusive lock for that same row, which it cannot have. Thus, before MySQL 5.1.5, enabling `innodb_locks_unsafe_for_binlog' still does not permit operations such as *Note `UPDATE': update. to overtake other similar operations (such as another *Note `UPDATE': update.) even when they affect different rows. * `innodb_log_arch_dir' This variable is deprecated, and was removed in MySQL 5.1.21. * `innodb_log_archive' This variable is deprecated, and was removed in MySQL 5.1.18. * `innodb_log_buffer_size' Options for innodb_log_buffer_size *Command-Line `--innodb_log_buffer_size=#' Format* *Option-File Format* `innodb_log_buffer_size' *Option Sets Yes, Variable* `innodb_log_buffer_size' *Variable Name* `innodb_log_buffer_size' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `numeric' *Default* `1048576' *Range* `1048576-4294967295' The size in bytes of the buffer that `InnoDB' uses to write to the log files on disk. The default value is 1MB for the built-in *Note `InnoDB': innodb-storage-engine, 8MB for `InnoDB Plugin'. Sensible values range from 1MB to 8MB. A large log buffer enables large transactions to run without a need to write the log to disk before the transactions commit. Thus, if you have big transactions, making the log buffer larger saves disk I/O. * `innodb_log_file_size' Options for innodb_log_file_size *Command-Line `--innodb_log_file_size=#' Format* *Option-File Format* `innodb_log_file_size' *Option Sets Yes, Variable* `innodb_log_file_size' *Variable Name* `innodb_log_file_size' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `numeric' *Default* `5242880' *Range* `1048576-4294967295' The size in bytes of each log file in a log group. The combined size of log files must be less than 4GB. The default value is 5MB. Sensible values range from 1MB to 1/N-th of the size of the buffer pool, where N is the number of log files in the group. The larger the value, the less checkpoint flush activity is needed in the buffer pool, saving disk I/O. But larger log files also mean that recovery is slower in case of a crash. * `innodb_log_files_in_group' Options for innodb_log_files_in_group *Command-Line `--innodb_log_files_in_group=#' Format* *Option-File Format* `innodb_log_files_in_group' *Option Sets Yes, Variable* `innodb_log_files_in_group' *Variable Name* `innodb_log_files_in_group' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `numeric' *Default* `2' *Range* `2-100' The number of log files in the log group. `InnoDB' writes to the files in a circular fashion. The default (and recommended) value is 2. * `innodb_log_group_home_dir' Options for innodb_log_group_home_dir *Command-Line `--innodb_log_group_home_dir=path' Format* *Option-File Format* `innodb_log_group_home_dir' *Option Sets Yes, Variable* `innodb_log_group_home_dir' *Variable Name* `innodb_log_group_home_dir' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `file name' The directory path to the `InnoDB' log files. If you do not specify any `InnoDB' log variables, the default is to create two 5MB files names `ib_logfile0' and `ib_logfile1' in the MySQL data directory. * `innodb_max_dirty_pages_pct' Options for innodb_max_dirty_pages_pct *Command-Line `--innodb_max_dirty_pages_pct=#' Format* *Option-File Format* `innodb_max_dirty_pages_pct' *Option Sets Yes, Variable* `innodb_max_dirty_pages_pct' *Variable Name* `innodb_max_dirty_pages_pct' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `numeric' *Default* `90' *Range* `0-100' This is an integer in the range from 0 to 100. The default value is 90 for the built-in *Note `InnoDB': innodb-storage-engine, 75 for `InnoDB Plugin'. The main thread in `InnoDB' tries to write pages from the buffer pool so that the percentage of dirty (not yet written) pages will not exceed this value. * `innodb_max_purge_lag' Options for innodb_max_purge_lag *Command-Line `--innodb_max_purge_lag=#' Format* *Option-File Format* `innodb_max_purge_lag' *Option Sets Yes, Variable* `innodb_max_purge_lag' *Variable Name* `innodb_max_purge_lag' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `numeric' *Default* `0' *Range* `0-4294967295' This variable controls how to delay *Note `INSERT': insert, *Note `UPDATE': update, and *Note `DELETE': delete. operations when purge operations are lagging (see *Note innodb-multi-versioning::). The default value 0 (no delays). The `InnoDB' transaction system maintains a list of transactions that have index records delete-marked by *Note `UPDATE': update. or *Note `DELETE': delete. operations. Let the length of this list be PURGE_LAG. When PURGE_LAG exceeds `innodb_max_purge_lag', each *Note `INSERT': insert, *Note `UPDATE': update, and *Note `DELETE': delete. operation is delayed by ((PURGE_LAG/`innodb_max_purge_lag')x10)-5 milliseconds. The delay is computed in the beginning of a purge batch, every ten seconds. The operations are not delayed if purge cannot run because of an old consistent read view that could see the rows to be purged. A typical setting for a problematic workload might be 1 million, assuming that transactions are small, only 100 bytes in size, and it is permissible to have 100MB of unpurged `InnoDB' table rows. The lag value is displayed as the history list length in the `TRANSACTIONS' section of InnoDB Monitor output. For example, if the output includes the following lines, the lag value is 20: ------------ TRANSACTIONS ------------ Trx id counter 0 290328385 Purge done for trx's n:o < 0 290315608 undo n:o < 0 17 History list length 20 * `innodb_mirrored_log_groups' The number of identical copies of log groups to keep for the database. This should be set to 1. * `innodb_old_blocks_pct' Options for innodb_old_blocks_pct *Version Introduced* 5.1.41 *Command-Line `--innodb_old_blocks_pct=#' Format* *Option-File Format* `innodb_old_blocks_pct' *Variable Name* `innodb_old_blocks_pct' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `numeric' *Default* `37' *Range* `5-95' (`InnoDB Plugin' only) Specifies the approximate percentage of the *Note `InnoDB': innodb-storage-engine. buffer pool used for the old block sublist. The range of values is 5 to 95. The default value is 37 (that is, 3/8 of the pool). See *Note innodb-buffer-pool:: This variable was added in MySQL 5.1.41. * `innodb_old_blocks_time' Options for innodb_old_blocks_time *Version Introduced* 5.1.41 *Command-Line `--innodb_old_blocks_time=#' Format* *Option-File Format* `innodb_old_blocks_time' *Variable Name* `innodb_old_blocks_time' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `numeric' *Default* `0' *Range* `0-2**32-1' (`InnoDB Plugin' only) Specifies how long in milliseconds (ms) a block inserted into the old sublist must stay there after its first access before it can be moved to the new sublist. The default value is 0: A block inserted into the old sublist moves immediately to the new sublist the first time it is accessed, no matter how soon after insertion the access occurs. If the value is greater than 0, blocks remain in the old sublist until an access occurs at least that many ms after the first access. For example, a value of 1000 causes blocks to stay in the old sublist for 1 second after the first access before they become eligible to move to the new sublist. See *Note innodb-buffer-pool:: This variable was added in MySQL 5.1.41. * `innodb_open_files' Options for innodb_open_files *Command-Line `--innodb_open_files=#' Format* *Option-File Format* `innodb_open_files' *Variable Name* `innodb_open_files' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `numeric' *Default* `300' *Range* `10-4294967295' This variable is relevant only if you use multiple tablespaces in `InnoDB'. It specifies the maximum number of `.ibd' files that `InnoDB' can keep open at one time. The minimum value is 10. The default value is 300. The file descriptors used for `.ibd' files are for `InnoDB' only. They are independent of those specified by the `--open-files-limit' server option, and do not affect the operation of the table cache. * `innodb_read_ahead_threshold' Options for innodb_read_ahead_threshold *Version Introduced* 5.1.38 *Command-Line `--innodb_read_ahead_threshold=#' Format* *Option-File Format* `innodb_read_ahead_threshold' *Option Sets Yes, Variable* `innodb_read_ahead_threshold' *Variable Name* `innodb_read_ahead_threshold' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `numeric' *Default* `56' *Range* `0-64' (`InnoDB Plugin' only) Controls the sensitivity of linear read-ahead that `InnoDB' uses to prefetch pages into the buffer cache. If `InnoDB' reads at least `innodb_read_ahead_threshold' pages sequentially from an extent (64 pages), it initiates an asynchronous read for the entire following extent. The permissible range of values is 0 to 64. The default is 56: `InnoDB' must read at least 56 pages sequentially from an extent to initiate an asynchronous read for the following extent. This variable was added in MySQL 5.1.38. * `innodb_read_io_threads' Options for innodb_read_io_threads *Version Introduced* 5.1.38 *Command-Line `--innodb_read_io_threads=#' Format* *Option-File Format* `innodb_read_io_threads' *Option Sets Yes, Variable* `innodb_read_io_threads' *Variable Name* `innodb_read_io_threads' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `numeric' *Default* `4' *Range* `1-64' (`InnoDB Plugin' only) The number of I/O threads for read operations in `InnoDB'. The default value is 4. This variable was added in MySQL 5.1.38. * `innodb_replication_delay' Options for innodb_replication_delay *Version Introduced* 5.1.38 *Command-Line `--innodb_replication_delay=#' Format* *Option-File Format* `innodb_replication_delay' *Option Sets Yes, Variable* `innodb_replication_delay' *Variable Name* `innodb_replication_delay' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `numeric' *Default* `0' *Range* `0-4294967295' (`InnoDB Plugin' only) The replication thread delay (in ms) on a slave server if `innodb_thread_concurrency' is reached. This variable was added in MySQL 5.1.38. * `innodb_rollback_on_timeout' Options for innodb_rollback_on_timeout *Version Introduced* 5.1.15 *Command-Line `--innodb_rollback_on_timeout' Format* *Option-File Format* `innodb_rollback_on_timeout' *Option Sets Yes, Variable* `innodb_rollback_on_timeout' *Variable Name* `innodb_rollback_on_timeout' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `boolean' *Default* `OFF' In MySQL 5.1, `InnoDB' rolls back only the last statement on a transaction timeout by default. If `--innodb_rollback_on_timeout' is specified, a transaction timeout causes `InnoDB' to abort and roll back the entire transaction (the same behavior as in MySQL 4.1). This variable was added in MySQL 5.1.15. * `innodb_spin_wait_delay' Options for innodb_spin_wait_delay *Version Introduced* 5.1.38 *Command-Line `--innodb_spin_wait_delay=#' Format* *Option-File Format* `innodb_spin_wait_delay' *Option Sets Yes, Variable* `innodb_spin_wait_delay' *Variable Name* `innodb_spin_wait_delay' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `numeric' *Default* `6' *Range* `0-4294967295' (`InnoDB Plugin' only) The maximum delay between polls for a spin lock. The default value is 6. This variable was added in MySQL 5.1.38. * `innodb_stats_on_metadata' Options for innodb_stats_on_metadata *Version Introduced* 5.1.17 *Command-Line `--innodb_stats_on_metadata' Format* *Option-File Format* `innodb_stats_on_metadata' *Option Sets Yes, Variable* `innodb_stats_on_metadata' *Variable Name* `innodb_stats_on_metadata' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `boolean' *Default* `ON' When this variable is enabled (which is the default, as before the variable was created), `InnoDB' updates statistics during metadata statements such as *Note `SHOW TABLE STATUS': show-table-status. or *Note `SHOW INDEX': show-index, or when accessing the `INFORMATION_SCHEMA' tables *Note `TABLES': tables-table. or *Note `STATISTICS': statistics-table. (These updates are similar to what happens for *Note `ANALYZE TABLE': analyze-table.) When disabled, `InnoDB' does not updates statistics during these operations. Disabling this variable can improve access speed for schemas that have a large number of tables or indexes. It can also improve the stability of execution plans for queries that involve `InnoDB' tables. This variable was added in MySQL 5.1.17. * `innodb_stats_sample_pages' Options for innodb_stats_sample_pages *Version Introduced* 5.1.38 *Command-Line `--innodb_stats_sample_pages=#' Format* *Option-File Format* `innodb_stats_sample_pages' *Option Sets Yes, Variable* `innodb_stats_sample_pages' *Variable Name* `innodb_stats_sample_pages' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `numeric' *Default* `8' *Range* `1-2**64-1' (`InnoDB Plugin' only) The number of index pages to sample for index distribution statistics such as are calculated by *Note `ANALYZE TABLE': analyze-table. The default value is 8. For more information, see Ease of Use and Reliability. This variable was added in MySQL 5.1.38. * `innodb_strict_mode' Options for innodb_strict_mode *Version Introduced* 5.1.38 *Command-Line `--innodb_strict_mode=#' Format* *Option-File Format* `innodb_strict_mode' *Option Sets Yes, Variable* `innodb_strict_mode' *Variable Name* `innodb_strict_mode' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `boolean' *Default* `OFF' (`InnoDB Plugin' only) Whether `InnoDB' returns errors rather than warnings for certain conditions. This is analogous to strict SQL mode. The default value is `OFF'. See InnoDB Strict Mode (http://dev.mysql.com/doc/innodb-plugin/1.0/en/innodb-other-changes-strict-mode.html) for a list of the conditions that are affected. This variable was added in MySQL 5.1.38. * `innodb_support_xa' Options for innodb_support_xa *Command-Line `--innodb_support_xa' Format* *Option-File Format* `innodb_support_xa' *Option Sets Yes, Variable* `innodb_support_xa' *Variable Name* `innodb_support_xa' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `boolean' *Default* `TRUE' Enables `InnoDB' support for two-phase commit in XA transactions, causing an extra disk flush for transaction preparation. This setting is the default. The XA mechanism is used internally and is essential for any server that has its binary log turned on and is accepting changes to its data from more than one thread. If you turn it off, transactions can be written to the binary log in a different order from the one in which the live database is committing them. This can produce different data when the binary log is replayed in disaster recovery or on a replication slave. Do not turn it off on a replication master server unless you have an unusual setup where only one thread is able to change data. For a server that is accepting data changes from only one thread, it is safe and recommended to turn off this option to improve performance for *Note `InnoDB': innodb-storage-engine. tables. For example, you can turn it off on replication slaves where only the replication SQL thread is changing data. You can also turn off this option if you do not need it for safe binary logging or replication, and you also do not use an external XA transaction manager. * `innodb_sync_spin_loops' Options for innodb_sync_spin_loops *Command-Line `--innodb_sync_spin_loops=#' Format* *Option-File Format* `innodb_sync_spin_loops' *Option Sets Yes, Variable* `innodb_sync_spin_loops' *Variable Name* `innodb_sync_spin_loops' *Variable Scope* Global *Dynamic Variable* Yes The number of times a thread waits for an `InnoDB' mutex to be freed before the thread is suspended. The default value is 20 for the built-in *Note `InnoDB': innodb-storage-engine, 30 for `InnoDB Plugin'. * `innodb_table_locks' Options for innodb_table_locks *Command-Line `--innodb_table_locks' Format* *Option-File Format* `innodb_table_locks' *Option Sets Yes, Variable* `innodb_table_locks' *Variable Name* `innodb_table_locks' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `boolean' *Default* `TRUE' If `autocommit = 0', `InnoDB' honors *Note `LOCK TABLES': lock-tables.; MySQL does not return from `LOCK TABLES ... WRITE' until all other threads have released all their locks to the table. The default value of `innodb_table_locks' is 1, which means that *Note `LOCK TABLES': lock-tables. causes InnoDB to lock a table internally if `autocommit = 0'. * `innodb_thread_concurrency' Options for innodb_thread_concurrency *Command-Line `--innodb_thread_concurrency=#' Format* *Option-File Format* `innodb_thread_concurrency' *Option Sets Yes, Variable* `innodb_thread_concurrency' *Variable Name* `innodb_thread_concurrency' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `numeric' *Default* `8' *Range* `0-1000' `InnoDB' tries to keep the number of operating system threads concurrently inside `InnoDB' less than or equal to the limit given by this variable. Once the number of threads reaches this limit, additional threads are placed into a wait state within a FIFO queue for execution. Threads waiting for locks are not counted in the number of concurrently executing threads. The correct value for this variable is dependent on environment and workload. You will need to try a range of different values to determine what value works for your applications. A recommended value is 2 times the number of CPUs plus the number of disks. The range of this variable is 0 to 1000. A value of 20 or higher is interpreted as infinite concurrency before MySQL 5.1.12. From 5.1.12 on, you can disable thread concurrency checking by setting the value to 0. Disabling thread concurrency checking enables InnoDB to create as many threads as it needs. The default value for the built-in *Note `InnoDB': innodb-storage-engine. is 20 before MySQL 5.1.11 and 8 from 5.1.11 on. The default for the `InnoDB Plugin' is 0. * `innodb_thread_sleep_delay' Options for innodb_thread_sleep_delay *Command-Line `--innodb_thread_sleep_delay=#' Format* *Option-File Format* `innodb_thread_sleep_delay' *Option Sets Yes, Variable* `innodb_thread_sleep_delay' *Variable Name* `innodb_thread_sleep_delay' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values (>= 5.1.0)* *Type* `numeric' *Default* `10000' How long `InnoDB' threads sleep before joining the `InnoDB' queue, in microseconds. The default value is 10,000. A value of 0 disables sleep. * `innodb_use_legacy_cardinality_algorithm' Options for innodb_use_legacy_cardinality_algorithm *Version Introduced* 5.1.35 *Command-Line `--innodb_use_legacy_cardinality_algorithm=#' Format* *Option-File Format* `innodb_use_legacy_cardinality_algorithm' *Option Sets Yes, Variable* `innodb_use_legacy_cardinality_algorithm' *Variable Name* `innodb_use_legacy_cardinality_algorithm' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `boolean' *Default* `ON' *Note `InnoDB': innodb-storage-engine. uses random numbers to generate dives into indexes for calculating index cardinality. However, under certain conditions, the algorithm does not generate random numbers, so *Note `ANALYZE TABLE': analyze-table. sometimes does not update cardinality estimates properly. An alternative algorithm was introduced in MySQL 5.1.35 with better randomization properties, and the `innodb_use_legacy_cardinality_algorithm', system variable which algorithm to use. The default value of the variable is 1 (`ON'), to use the original algorithm for compatibility with existing applications. The variable can be set to 0 (`OFF') to use the new algorithm with improved randomness. This variable is not used in `InnoDB Plugin' because the improved algorithm is used by default. Also, the number of random dives can be changed by modifying the `innodb_stats_sample_pages' system variable. * `innodb_use_sys_malloc' Options for innodb_use_sys_malloc *Version Introduced* 5.1.38 *Command-Line `--innodb_use_sys_malloc=#' Format* *Option-File Format* `innodb_use_sys_malloc' *Option Sets Yes, Variable* `innodb_use_sys_malloc' *Variable Name* `innodb_use_sys_malloc' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `boolean' *Default* `ON' (`InnoDB Plugin' only) Whether `InnoDB' uses the operating system memory allocator (`ON') or its own (`OFF'). The default value is `ON'. This variable was added in MySQL 5.1.38. * `innodb_version' (`InnoDB Plugin' only) The *Note `InnoDB': innodb-storage-engine. version number. This variable was added in MySQL 5.1.38. * `innodb_write_io_threads' Options for innodb_write_io_threads *Version Introduced* 5.1.38 *Command-Line `--innodb_write_io_threads=#' Format* *Option-File Format* `innodb_write_io_threads' *Option Sets Yes, Variable* `innodb_write_io_threads' *Variable Name* `innodb_write_io_threads' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `numeric' *Default* `4' *Range* `1-64' (`InnoDB Plugin' only) The number of I/O threads for write operations in `InnoDB'. The default value is 4. This variable was added in MySQL 5.1.38. * `sync_binlog' Options for sync_binlog *Command-Line `--sync-binlog=#' Format* *Option-File Format* `sync_binlog' *Option Sets Yes, Variable* `sync_binlog' *Variable Name* `sync_binlog' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Platform Bit Size* `32' *Type* `numeric' *Default* `0' *Range* `0-4294967295' *Permitted Values * *Platform Bit Size* `64' *Type* `numeric' *Default* `0' *Range* `0-18446744073709547520' If the value of this variable is greater than 0, the MySQL server synchronizes its binary log to disk (using `fdatasync()') after every `sync_binlog' writes to the binary log. There is one write to the binary log per statement if autocommit is enabled, and one write per transaction otherwise. The default value of `sync_binlog' is 0, which does no synchronizing to disk. A value of 1 is the safest choice, because in the event of a crash you lose at most one statement or transaction from the binary log. However, it is also the slowest choice (unless the disk has a battery-backed cache, which makes synchronization very fast).  File: manual.info, Node: using-innodb-tables, Next: innodb-data-log-reconfiguration, Prev: innodb-parameters, Up: innodb-storage-engine 14.6.4 Creating and Using `InnoDB' Tables ----------------------------------------- * Menu: * innodb-transactions-with-different-apis:: How to Use Transactions in `InnoDB' with Different APIs * converting-tables-to-innodb:: Converting Tables from Other Storage Engines to `InnoDB' * innodb-auto-increment-handling:: `AUTO_INCREMENT' Handling in `InnoDB' * innodb-foreign-key-constraints:: `FOREIGN KEY' Constraints * innodb-and-mysql-replication:: `InnoDB' and MySQL Replication To create an `InnoDB' table, specify an `ENGINE = InnoDB' option in the *Note `CREATE TABLE': create-table. statement: CREATE TABLE customers (a INT, b CHAR (20), INDEX (a)) ENGINE=InnoDB; The statement creates a table and an index on column `a' in the `InnoDB' tablespace that consists of the data files that you specified in `my.cnf'. In addition, MySQL creates a file `customers.frm' in the `test' directory under the MySQL database directory. Internally, `InnoDB' adds an entry for the table to its own data dictionary. The entry includes the database name. For example, if `test' is the database in which the `customers' table is created, the entry is for `'test/customers''. This means you can create a table of the same name `customers' in some other database, and the table names do not collide inside `InnoDB'. You can query the amount of free space in the `InnoDB' tablespace by issuing a *Note `SHOW TABLE STATUS': show-table-status. statement for any `InnoDB' table. The amount of free space in the tablespace appears in the `Data_free' section in the output of *Note `SHOW TABLE STATUS': show-table-status. (or the `Comment' section prior to MySQL 5.1.24). For example: SHOW TABLE STATUS FROM test LIKE 'customers' The statistics *Note `SHOW': show. displays for `InnoDB' tables are only approximate. They are used in SQL optimization. Table and index reserved sizes in bytes are accurate, though.  File: manual.info, Node: innodb-transactions-with-different-apis, Next: converting-tables-to-innodb, Prev: using-innodb-tables, Up: using-innodb-tables 14.6.4.1 How to Use Transactions in `InnoDB' with Different APIs ................................................................ By default, each client that connects to the MySQL server begins with autocommit mode enabled, which automatically commits every SQL statement as you execute it. To use multiple-statement transactions, you can switch autocommit off with the SQL statement `SET autocommit = 0' and end each transaction with either *Note `COMMIT': commit. or *Note `ROLLBACK': commit. If you want to leave autocommit on, you can begin your transactions within *Note `START TRANSACTION': commit. and end them with *Note `COMMIT': commit. or *Note `ROLLBACK': commit. The following example shows two transactions. The first is committed; the second is rolled back. shell> mysql test mysql> CREATE TABLE customer (a INT, b CHAR (20), INDEX (a)) -> ENGINE=InnoDB; Query OK, 0 rows affected (0.00 sec) mysql> START TRANSACTION; Query OK, 0 rows affected (0.00 sec) mysql> INSERT INTO customer VALUES (10, 'Heikki'); Query OK, 1 row affected (0.00 sec) mysql> COMMIT; Query OK, 0 rows affected (0.00 sec) mysql> SET autocommit=0; Query OK, 0 rows affected (0.00 sec) mysql> INSERT INTO customer VALUES (15, 'John'); Query OK, 1 row affected (0.00 sec) mysql> ROLLBACK; Query OK, 0 rows affected (0.00 sec) mysql> SELECT * FROM customer; +------+--------+ | a | b | +------+--------+ | 10 | Heikki | +------+--------+ 1 row in set (0.00 sec) mysql> In APIs such as PHP, Perl DBI, JDBC, ODBC, or the standard C call interface of MySQL, you can send transaction control statements such as *Note `COMMIT': commit. to the MySQL server as strings just like any other SQL statements such as *Note `SELECT': select. or *Note `INSERT': insert. Some APIs also offer separate special transaction commit and rollback functions or methods.  File: manual.info, Node: converting-tables-to-innodb, Next: innodb-auto-increment-handling, Prev: innodb-transactions-with-different-apis, Up: using-innodb-tables 14.6.4.2 Converting Tables from Other Storage Engines to `InnoDB' ................................................................. To convert a non-`InnoDB' table to use `InnoDB' use *Note `ALTER TABLE': alter-table.: ALTER TABLE t1 ENGINE=InnoDB; *Important*: Do not convert MySQL system tables in the `mysql' database (such as `user' or `host') to the `InnoDB' type. This is an unsupported operation. The system tables must always be of the `MyISAM' type. `InnoDB' does not have a special optimization for separate index creation the way the `MyISAM' storage engine does. Therefore, it does not pay to export and import the table and create indexes afterward. The fastest way to alter a table to `InnoDB' is to do the inserts directly to an `InnoDB' table. That is, use `ALTER TABLE ... ENGINE=INNODB', or create an empty `InnoDB' table with identical definitions and insert the rows with `INSERT INTO ... SELECT * FROM ...'. If you have `UNIQUE' constraints on secondary keys, you can speed up a table import by turning off the uniqueness checks temporarily during the import operation: SET unique_checks=0; ... IMPORT OPERATION ... SET unique_checks=1; For big tables, this saves a lot of disk I/O because `InnoDB' can then use its insert buffer to write secondary index records as a batch. Be certain that the data contains no duplicate keys. `unique_checks' permits but does not require storage engines to ignore duplicate keys. To get better control over the insertion process, it might be good to insert big tables in pieces: INSERT INTO newtable SELECT * FROM oldtable WHERE yourkey > something AND yourkey <= somethingelse; After all records have been inserted, you can rename the tables. During the conversion of big tables, increase the size of the `InnoDB' buffer pool to reduce disk I/O. Do not use more than 80% of the physical memory, though. You can also increase the sizes of the `InnoDB' log files. Make sure that you do not fill up the tablespace: `InnoDB' tables require a lot more disk space than `MyISAM' tables. If an *Note `ALTER TABLE': alter-table. operation runs out of space, it starts a rollback, and that can take hours if it is disk-bound. For inserts, `InnoDB' uses the insert buffer to merge secondary index records to indexes in batches. That saves a lot of disk I/O. For rollback, no such mechanism is used, and the rollback can take 30 times longer than the insertion. In the case of a runaway rollback, if you do not have valuable data in your database, it may be advisable to kill the database process rather than wait for millions of disk I/O operations to complete. For the complete procedure, see *Note forcing-innodb-recovery::. If you want all your (nonsystem) tables to be created as `InnoDB' tables, add the line `default-storage-engine=innodb' to the `[mysqld]' section of your server option file.  File: manual.info, Node: innodb-auto-increment-handling, Next: innodb-foreign-key-constraints, Prev: converting-tables-to-innodb, Up: using-innodb-tables 14.6.4.3 `AUTO_INCREMENT' Handling in `InnoDB' .............................................. * Menu: * innodb-auto-increment-traditional:: `Traditional' `InnoDB' Auto-Increment Locking * innodb-auto-increment-configurable:: Configurable `InnoDB' Auto-Increment Locking Beginning with MySQL 5.1.22, `InnoDB' provides a locking strategy that significantly improves scalability and performance of SQL statements that add rows to tables with `AUTO_INCREMENT' columns. This section provides background information on the original (`traditional') implementation of auto-increment locking in `InnoDB', explains the configurable locking mechanism, documents the parameter for configuring the mechanism, and describes its behavior and interaction with replication.  File: manual.info, Node: innodb-auto-increment-traditional, Next: innodb-auto-increment-configurable, Prev: innodb-auto-increment-handling, Up: innodb-auto-increment-handling 14.6.4.4 `Traditional' `InnoDB' Auto-Increment Locking ...................................................... The original implementation of auto-increment handling in `InnoDB' uses the following strategy to prevent problems when using the binary log for statement-based replication or for certain recovery scenarios. If you specify an `AUTO_INCREMENT' column for an `InnoDB' table, the table handle in the `InnoDB' data dictionary contains a special counter called the auto-increment counter that is used in assigning new values for the column. This counter is stored only in main memory, not on disk. `InnoDB' uses the following algorithm to initialize the auto-increment counter for a table `t' that contains an `AUTO_INCREMENT' column named `ai_col': After a server startup, for the first insert into a table `t', `InnoDB' executes the equivalent of this statement: SELECT MAX(ai_col) FROM t FOR UPDATE; `InnoDB' increments the value retrieved by the statement and assigns it to the column and to the auto-increment counter for the table. By default, the value is incremented by one. This default can be overridden by the `auto_increment_increment' configuration setting. If the table is empty, `InnoDB' uses the value `1'. This default can be overridden by the `auto_increment_offset' configuration setting. If a *Note `SHOW TABLE STATUS': show-table-status. statement examines the table `t' before the auto-increment counter is initialized, `InnoDB' initializes but does not increment the value and stores it for use by later inserts. This initialization uses a normal exclusive-locking read on the table and the lock lasts to the end of the transaction. `InnoDB' follows the same procedure for initializing the auto-increment counter for a freshly created table. After the auto-increment counter has been initialized, if a you do not explicitly specify a value for an `AUTO_INCREMENT' column, `InnoDB' increments the counter and assigns the new value to the column. If you insert a row that explicitly specifies the column value, and the value is bigger than the current counter value, the counter is set to the specified column value. When accessing the auto-increment counter, `InnoDB' uses a special table-level `AUTO-INC' lock that it keeps to the end of the current SQL statement, not to the end of the transaction. The special lock release strategy was introduced to improve concurrency for inserts into a table containing an `AUTO_INCREMENT' column. Nevertheless, two transactions cannot have the `AUTO-INC' lock on the same table simultaneously, which can have a performance impact if the `AUTO-INC' lock is held for a long time. That might be the case for a statement such as `INSERT INTO t1 ... SELECT ... FROM t2' that inserts all rows from one table into another. `InnoDB' uses the in-memory auto-increment counter as long as the server runs. When the server is stopped and restarted, `InnoDB' reinitializes the counter for each table for the first *Note `INSERT': insert. to the table, as described earlier. You may see gaps in the sequence of values assigned to the `AUTO_INCREMENT' column if you roll back transactions that have generated numbers using the counter. If a user specifies `NULL' or `0' for the `AUTO_INCREMENT' column in an *Note `INSERT': insert, `InnoDB' treats the row as if the value was not specified and generates a new value for it. The behavior of the auto-increment mechanism is not defined if you assign a negative value to the column, or if the value becomes bigger than the maximum integer that can be stored in the specified integer type. An `AUTO_INCREMENT' column must appear as the first column in an index on an `InnoDB' table. `InnoDB' supports the `AUTO_INCREMENT = N' table option in *Note `CREATE TABLE': create-table. and *Note `ALTER TABLE': alter-table. statements, to set the initial counter value or alter the current counter value. The effect of this option is canceled by a server restart, for reasons discussed earlier in this section.  File: manual.info, Node: innodb-auto-increment-configurable, Prev: innodb-auto-increment-traditional, Up: innodb-auto-increment-handling 14.6.4.5 Configurable `InnoDB' Auto-Increment Locking ..................................................... As described in the previous section, `InnoDB' uses a special lock called the table-level `AUTO-INC' lock for inserts into tables with `AUTO_INCREMENT' columns. This lock is normally held to the end of the statement (not to the end of the transaction), to ensure that auto-increment numbers are assigned in a predictable and repeatable order for a given sequence of *Note `INSERT': insert. statements. In the case of statement-based replication, this means that when an SQL statement is replicated on a slave server, the same values are used for the auto-increment column as on the master server. The result of execution of multiple *Note `INSERT': insert. statements is deterministic, and the slave reproduces the same data as on the master. If auto-increment values generated by multiple *Note `INSERT': insert. statements were interleaved, the result of two concurrent *Note `INSERT': insert. statements would be nondeterministic, and could not reliably be propagated to a slave server using statement-based replication. To make this clear, consider an example that uses this table: CREATE TABLE t1 ( c1 INT(11) NOT NULL AUTO_INCREMENT, c2 VARCHAR(10) DEFAULT NULL, PRIMARY KEY (c1) ) ENGINE=InnoDB; Suppose that there are two transactions running, each inserting rows into a table with an `AUTO_INCREMENT' column. One transaction is using an *Note `INSERT ... SELECT': insert-select. statement that inserts 1000 rows, and another is using a simple *Note `INSERT': insert. statement that inserts one row: Tx1: INSERT INTO t1 (c2) SELECT 1000 rows from another table ... Tx2: INSERT INTO t1 (c2) VALUES ('xxx'); `InnoDB' cannot tell in advance how many rows will be retrieved from the *Note `SELECT': select. in the *Note `INSERT': insert. statement in Tx1, and it assigns the auto-increment values one at a time as the statement proceeds. With a table-level lock, held to the end of the statement, only one *Note `INSERT': insert. statement referring to table `t1' can execute at a time, and the generation of auto-increment numbers by different statements is not interleaved. The auto-increment value generated by the Tx1 *Note `INSERT ... SELECT': insert-select. statement will be consecutive, and the (single) auto-increment value used by the *Note `INSERT': insert. statement in Tx2 will either be smaller or larger than all those used for Tx1, depending on which statement executes first. As long as the SQL statements execute in the same order when replayed from the binary log (when using statement-based replication, or in recovery scenarios), the results will be the same as they were when Tx1 and Tx2 first ran. Thus, table-level locks held until the end of a statement make *Note `INSERT': insert. statements using auto-increment safe for use with statement-based replication. However, those locks limit concurrency and scalability when multiple transactions are executing insert statements at the same time. In the preceding example, if there were no table-level lock, the value of the auto-increment column used for the *Note `INSERT': insert. in Tx2 depends on precisely when the statement executes. If the *Note `INSERT': insert. of Tx2 executes while the *Note `INSERT': insert. of Tx1 is running (rather than before it starts or after it completes), the specific auto-increment values assigned by the two *Note `INSERT': insert. statements are nondeterministic, and may vary from run to run. As of MySQL 5.1.22, `InnoDB' can avoid using the table-level `AUTO-INC' lock for a class of *Note `INSERT': insert. statements where the number of rows is known in advance, and still preserve deterministic execution and safety for statement-based replication. Further, if you are not using the binary log to replay SQL statements as part of recovery or replication, you can entirely eliminate use of the table-level `AUTO-INC' lock for even greater concurrency and performance--at the cost of permitting gaps in auto-increment numbers assigned by a statement and potentially having the numbers assigned by concurrently executing statements interleaved. For *Note `INSERT': insert. statements where the number of rows to be inserted is known at the beginning of processing the statement, `InnoDB' quickly allocates the required number of auto-increment values without taking any lock, but only if there is no concurrent session already holding the table-level `AUTO-INC' lock (because that other statement will be allocating auto-increment values one-by-one as it proceeds). More precisely, such an *Note `INSERT': insert. statement obtains auto-increment values under the control of a mutex (a light-weight lock) that is _not_ held until the statement completes, but only for the duration of the allocation process. This new locking scheme enables much greater scalability, but it does introduce some subtle differences in how auto-increment values are assigned compared to the original mechanism. To describe the way auto-increment works in `InnoDB', the following discussion defines some terms, and explains how `InnoDB' behaves using different settings of the new `innodb_autoinc_lock_mode' configuration parameter. Additional considerations are described following the explanation of auto-increment locking behavior. First, some definitions: * `*Note `INSERT': insert.-like' statements All statements that generate new rows in a table, including *Note `INSERT': insert, *Note `INSERT ... SELECT': insert-select, *Note `REPLACE': replace, *Note `REPLACE ... SELECT': replace, and *Note `LOAD DATA': load-data. * `Simple inserts' Statements for which the number of rows to be inserted can be determined in advance (when the statement is initially processed). This includes single-row and multiple-row *Note `INSERT': insert. and *Note `REPLACE': replace. statements that do not have a nested subquery, but not *Note `INSERT ... ON DUPLICATE KEY UPDATE': insert-on-duplicate. * `Bulk inserts' Statements for which the number of rows to be inserted (and the number of required auto-increment values) is not known in advance. This includes *Note `INSERT ... SELECT': insert-select, *Note `REPLACE ... SELECT': replace, and *Note `LOAD DATA': load-data. statements, but not plain `INSERT'. `InnoDB' will assign new values for the `AUTO_INCREMENT' column one at a time as each row is processed. * `Mixed-mode inserts' These are `simple insert' statements that specify the auto-increment value for some (but not all) of the new rows. An example follows, where `c1' is an `AUTO_INCREMENT' column of table `t1': INSERT INTO t1 (c1,c2) VALUES (1,'a'), (NULL,'b'), (5,'c'), (NULL,'d'); Another type of `mixed-mode insert' is *Note `INSERT ... ON DUPLICATE KEY UPDATE': insert-on-duplicate, which in the worst case is in effect an *Note `INSERT': insert. followed by a *Note `UPDATE': update, where the allocated value for the `AUTO_INCREMENT' column may or may not be used during the update phase. Beginning with MySQL 5.1.22, there is a configuration parameter that controls how `InnoDB' uses locking when generating values for `AUTO_INCREMENT' columns. This parameter can be set using the `--innodb-autoinc-lock-mode' option at *Note `mysqld': mysqld. startup. In general, if you encounter problems with the way auto-increment works (which will most likely involve replication), you can force use of the original behavior by setting the lock mode to 0. There are three possible settings for the `innodb_autoinc_lock_mode' parameter: * `innodb_autoinc_lock_mode = 0' (`traditional' lock mode) This lock mode provides the same behavior as before `innodb_autoinc_lock_mode' existed. For all `*Note `INSERT': insert.-like' statements, a special table-level `AUTO-INC' lock is obtained and held to the end of the statement. This assures that the auto-increment values assigned by any given statement are consecutive (although `gaps' can exist within a table if a transaction that generated auto-increment values is rolled back, as discussed later). This lock mode is provided only for backward compatibility and performance testing. There is little reason to use this lock mode unless you use `mixed-mode inserts' and care about the important difference in semantics described later. * `innodb_autoinc_lock_mode = 1' (`consecutive' lock mode) This is the default lock mode. In this mode, `bulk inserts' use the special `AUTO-INC' table-level lock and hold it until the end of the statement. This applies to all *Note `INSERT ... SELECT': insert-select, *Note `REPLACE ... SELECT': replace, and *Note `LOAD DATA': load-data. statements. Only one statement holding the `AUTO-INC' lock can execute at a time. With this lock mode, `simple inserts' (only) use a new locking model where a light-weight mutex is used during the allocation of auto-increment values, and no table-level `AUTO-INC' lock is used, unless an `AUTO-INC' lock is held by another transaction. If another transaction does hold an `AUTO-INC' lock, a `simple insert' waits for the `AUTO-INC' lock, as if it too were a `bulk insert.' This lock mode ensures that, in the presence of *Note `INSERT': insert. statements where the number of rows is not known in advance (and where auto-increment numbers are assigned as the statement progresses), all auto-increment values assigned by any `*Note `INSERT': insert.-like' statement are consecutive, and operations are safe for statement-based replication. Simply put, the important impact of this lock mode is significantly better scalability. This mode is safe for use with statement-based replication. Further, as with `traditional' lock mode, auto-increment numbers assigned by any given statement are _consecutive_. In this mode, there is _no change_ in semantics compared to `traditional' mode for any statement that uses auto-increment, with one important exception. The exception is for `mixed-mode inserts', where the user provides explicit values for an `AUTO_INCREMENT' column for some, but not all, rows in a multiple-row `simple insert.' For such inserts, `InnoDB' will allocate more auto-increment values than the number of rows to be inserted. However, all values automatically assigned are consecutively generated (and thus higher than) the auto-increment value generated by the most recently executed previous statement. `Excess' numbers are lost. A similar situation exists if you use *Note `INSERT ... ON DUPLICATE KEY UPDATE': insert-on-duplicate. This statement is also classified as a `mixed-mode insert' since an auto-increment value is not necessarily generated for each row. Because `InnoDB' allocates the auto-increment value before the insert is actually attempted, it cannot know whether an inserted value will be a duplicate of an existing value and thus cannot know whether the auto-increment value it generates will be used for a new row. Therefore, if you are using statement-based replication, either avoid *Note `INSERT ... ON DUPLICATE KEY UPDATE': insert-on-duplicate. or use `innodb_autoinc_lock_mode = 0' (`traditional' lock mode). * `innodb_autoinc_lock_mode = 2' (`interleaved' lock mode) In this lock mode, no `*Note `INSERT': insert.-like' statements use the table-level `AUTO-INC' lock, and multiple statements can execute at the same time. This is the fastest and most scalable lock mode, but it is _not safe_ when using statement-based replication or recovery scenarios when SQL statements are replayed from the binary log. In this lock mode, auto-increment values are guaranteed to be unique and monotonically increasing across all concurrently executing `*Note `INSERT': insert.-like' statements. However, because multiple statements can be generating numbers at the same time (that is, allocation of numbers is _interleaved_ across statements), the values generated for the rows inserted by any given statement may not be consecutive. If the only statements executing are `simple inserts' where the number of rows to be inserted is known ahead of time, there will be no gaps in the numbers generated for a single statement, except for `mixed-mode inserts.' However, when `bulk inserts' are executed, there may be gaps in the auto-increment values assigned by any given statement. The auto-increment locking modes provided by `innodb_autoinc_lock_mode' have several usage implications: * Using auto-increment with replication If you are using statement-based replication, set `innodb_autoinc_lock_mode' to 0 or 1 and use the same value on the master and its slaves. Auto-increment values are not ensured to be the same on the slaves as on the master if you use `innodb_autoinc_lock_mode' = 2 (`interleaved') or configurations where the master and slaves do not use the same lock mode. If you are using row-based replication, all of the auto-increment lock modes are safe. Row-based replication is not sensitive to the order of execution of the SQL statements. * `Lost' auto-increment values and sequence gaps In all lock modes (0, 1, and 2), if a transaction that generated auto-increment values rolls back, those auto-increment values are `lost.' Once a value is generated for an auto-increment column, it cannot be rolled back, whether or not the `*Note `INSERT': insert.-like' statement is completed, and whether or not the containing transaction is rolled back. Such lost values are not reused. Thus, there may be gaps in the values stored in an `AUTO_INCREMENT' column of a table. * Gaps in auto-increment values for `bulk inserts' With `innodb_autoinc_lock_mode' set to 0 (`traditional') or 1 (`consecutive'), the auto-increment values generated by any given statement will be consecutive, without gaps, because the table-level `AUTO-INC' lock is held until the end of the statement, and only one such statement can execute at a time. With `innodb_autoinc_lock_mode' set to 2 (`interleaved'), there may be gaps in the auto-increment values generated by `bulk inserts,' but only if there are concurrently executing `*Note `INSERT': insert.-like' statements. For lock modes 1 or 2, gaps may occur between successive statements because for bulk inserts the exact number of auto-increment values required by each statement may not be known and overestimation is possible. * Auto-increment values assigned by `mixed-mode inserts' Consider a `mixed-mode insert,' where a `simple insert' specifies the auto-increment value for some (but not all) resulting rows. Such a statement will behave differently in lock modes 0, 1, and 2. For example, assume `c1' is an `AUTO_INCREMENT' column of table `t1', and that the most recent automatically generated sequence number is 100. Consider the following `mixed-mode insert' statement: INSERT INTO t1 (c1,c2) VALUES (1,'a'), (NULL,'b'), (5,'c'), (NULL,'d'); With `innodb_autoinc_lock_mode' set to 0 (`traditional'), the four new rows will be: +-----+------+ | c1 | c2 | +-----+------+ | 1 | a | | 101 | b | | 5 | c | | 102 | d | +-----+------+ The next available auto-increment value will be 103 because the auto-increment values are allocated one at a time, not all at once at the beginning of statement execution. This result is true whether or not there are concurrently executing `*Note `INSERT': insert.-like' statements (of any type). With `innodb_autoinc_lock_mode' set to 1 (`consecutive'), the four new rows will also be: +-----+------+ | c1 | c2 | +-----+------+ | 1 | a | | 101 | b | | 5 | c | | 102 | d | +-----+------+ However, in this case, the next available auto-increment value will be 105, not 103 because four auto-increment values are allocated at the time the statement is processed, but only two are used. This result is true whether or not there are concurrently executing `*Note `INSERT': insert.-like' statements (of any type). With `innodb_autoinc_lock_mode' set to mode 2 (`interleaved'), the four new rows will be: +-----+------+ | c1 | c2 | +-----+------+ | 1 | a | | X | b | | 5 | c | | Y | d | +-----+------+ The values of X and Y will be unique and larger than any previously generated rows. However, the specific values of X and Y will depend on the number of auto-increment values generated by concurrently executing statements. Finally, consider the following statement, issued when the most-recently generated sequence number was the value 4: INSERT INTO t1 (c1,c2) VALUES (1,'a'), (NULL,'b'), (5,'c'), (NULL,'d'); With any `innodb_autoinc_lock_mode' setting, this statement will generate a duplicate-key error 23000 (`Can't write; duplicate key in table') because 5 will be allocated for the row `(NULL, 'b')' and insertion of the row `(5, 'c')' will fail.  File: manual.info, Node: innodb-foreign-key-constraints, Next: innodb-and-mysql-replication, Prev: innodb-auto-increment-handling, Up: using-innodb-tables 14.6.4.6 `FOREIGN KEY' Constraints .................................. `InnoDB' supports foreign key constraints. The syntax for a foreign key constraint definition in `InnoDB' looks like this: [CONSTRAINT [SYMBOL]] FOREIGN KEY [INDEX_NAME] (INDEX_COL_NAME, ...) REFERENCES TBL_NAME (INDEX_COL_NAME,...) [ON DELETE REFERENCE_OPTION] [ON UPDATE REFERENCE_OPTION] REFERENCE_OPTION: RESTRICT | CASCADE | SET NULL | NO ACTION INDEX_NAME represents a foreign key ID. If given, this is ignored if an index for the foreign key is defined explicitly. Otherwise, if `InnoDB' creates an index for the foreign key, it uses INDEX_NAME for the index name. Foreign keys definitions are subject to the following conditions: * Both tables must be `InnoDB' tables and they must not be `TEMPORARY' tables. * Corresponding columns in the foreign key and the referenced key must have similar internal data types inside `InnoDB' so that they can be compared without a type conversion. _The size and sign of integer types must be the same_. The length of string types need not be the same. For nonbinary (character) string columns, the character set and collation must be the same. * `InnoDB' requires indexes on foreign keys and referenced keys so that foreign key checks can be fast and not require a table scan. In the referencing table, there must be an index where the foreign key columns are listed as the _first_ columns in the same order. Such an index is created on the referencing table automatically if it does not exist. (This is in contrast to some older versions, in which indexes had to be created explicitly or the creation of foreign key constraints would fail.) INDEX_NAME, if given, is used as described previously. * `InnoDB' permits a foreign key to reference any index column or group of columns. However, in the referenced table, there must be an index where the referenced columns are listed as the _first_ columns in the same order. * Index prefixes on foreign key columns are not supported. One consequence of this is that *Note `BLOB': blob. and *Note `TEXT': blob. columns cannot be included in a foreign key because indexes on those columns must always include a prefix length. * If the `CONSTRAINT SYMBOL' clause is given, the SYMBOL value must be unique in the database. If the clause is not given, `InnoDB' creates the name automatically. `InnoDB' rejects any *Note `INSERT': insert. or *Note `UPDATE': update. operation that attempts to create a foreign key value in a child table if there is no a matching candidate key value in the parent table. The action `InnoDB' takes for any *Note `UPDATE': update. or *Note `DELETE': delete. operation that attempts to update or delete a candidate key value in the parent table that has some matching rows in the child table is dependent on the _referential action_ specified using `ON UPDATE' and `ON DELETE' subclauses of the `FOREIGN KEY' clause. When the user attempts to delete or update a row from a parent table, and there are one or more matching rows in the child table, `InnoDB' supports five options regarding the action to be taken. If `ON DELETE' or `ON UPDATE' are not specified, the default action is `RESTRICT'. * `CASCADE': Delete or update the row from the parent table and automatically delete or update the matching rows in the child table. Both `ON DELETE CASCADE' and `ON UPDATE CASCADE' are supported. Between two tables, do not define several `ON UPDATE CASCADE' clauses that act on the same column in the parent table or in the child table. *Note*: Currently, cascaded foreign key actions do not activate triggers. * `SET NULL': Delete or update the row from the parent table and set the foreign key column or columns in the child table to `NULL'. This is valid only if the foreign key columns do not have the `NOT NULL' qualifier specified. Both `ON DELETE SET NULL' and `ON UPDATE SET NULL' clauses are supported. If you specify a `SET NULL' action, _make sure that you have not declared the columns in the child table as `NOT NULL'_. * `NO ACTION': In standard SQL, `NO ACTION' means _no action_ in the sense that an attempt to delete or update a primary key value is not permitted to proceed if there is a related foreign key value in the referenced table. `InnoDB' rejects the delete or update operation for the parent table. * `RESTRICT': Rejects the delete or update operation for the parent table. Specifying `RESTRICT' (or `NO ACTION') is the same as omitting the `ON DELETE' or `ON UPDATE' clause. (Some database systems have deferred checks, and `NO ACTION' is a deferred check. In MySQL, foreign key constraints are checked immediately, so `NO ACTION' is the same as `RESTRICT'.) * `SET DEFAULT': This action is recognized by the parser, but `InnoDB' rejects table definitions containing `ON DELETE SET DEFAULT' or `ON UPDATE SET DEFAULT' clauses. `InnoDB' supports foreign key references within a table. In these cases, `child table records' really refers to dependent records within the same table. Here is a simple example that relates `parent' and `child' tables through a single-column foreign key: CREATE TABLE parent (id INT NOT NULL, PRIMARY KEY (id) ) ENGINE=INNODB; CREATE TABLE child (id INT, parent_id INT, INDEX par_ind (parent_id), FOREIGN KEY (parent_id) REFERENCES parent(id) ON DELETE CASCADE ) ENGINE=INNODB; A more complex example in which a `product_order' table has foreign keys for two other tables. One foreign key references a two-column index in the `product' table. The other references a single-column index in the `customer' table: CREATE TABLE product (category INT NOT NULL, id INT NOT NULL, price DECIMAL, PRIMARY KEY(category, id)) ENGINE=INNODB; CREATE TABLE customer (id INT NOT NULL, PRIMARY KEY (id)) ENGINE=INNODB; CREATE TABLE product_order (no INT NOT NULL AUTO_INCREMENT, product_category INT NOT NULL, product_id INT NOT NULL, customer_id INT NOT NULL, PRIMARY KEY(no), INDEX (product_category, product_id), FOREIGN KEY (product_category, product_id) REFERENCES product(category, id) ON UPDATE CASCADE ON DELETE RESTRICT, INDEX (customer_id), FOREIGN KEY (customer_id) REFERENCES customer(id)) ENGINE=INNODB; `InnoDB' enables you to add a new foreign key constraint to a table by using *Note `ALTER TABLE': alter-table.: ALTER TABLE TBL_NAME ADD [CONSTRAINT [SYMBOL]] FOREIGN KEY [INDEX_NAME] (INDEX_COL_NAME, ...) REFERENCES TBL_NAME (INDEX_COL_NAME,...) [ON DELETE REFERENCE_OPTION] [ON UPDATE REFERENCE_OPTION] The foreign key can be self referential (referring to the same table). When you add a foreign key constraint to a table using *Note `ALTER TABLE': alter-table, _remember to create the required indexes first._ `InnoDB' supports the use of *Note `ALTER TABLE': alter-table. to drop foreign keys: ALTER TABLE TBL_NAME DROP FOREIGN KEY FK_SYMBOL; If the `FOREIGN KEY' clause included a `CONSTRAINT' name when you created the foreign key, you can refer to that name to drop the foreign key. Otherwise, the FK_SYMBOL value is internally generated by `InnoDB' when the foreign key is created. To find out the symbol value when you want to drop a foreign key, use the *Note `SHOW CREATE TABLE': show-create-table. statement. For example: mysql> SHOW CREATE TABLE ibtest11c\G *************************** 1. row *************************** Table: ibtest11c Create Table: CREATE TABLE `ibtest11c` ( `A` int(11) NOT NULL auto_increment, `D` int(11) NOT NULL default '0', `B` varchar(200) NOT NULL default '', `C` varchar(175) default NULL, PRIMARY KEY (`A`,`D`,`B`), KEY `B` (`B`,`C`), KEY `C` (`C`), CONSTRAINT `0_38775` FOREIGN KEY (`A`, `D`) REFERENCES `ibtest11a` (`A`, `D`) ON DELETE CASCADE ON UPDATE CASCADE, CONSTRAINT `0_38776` FOREIGN KEY (`B`, `C`) REFERENCES `ibtest11a` (`B`, `C`) ON DELETE CASCADE ON UPDATE CASCADE ) ENGINE=INNODB CHARSET=latin1 1 row in set (0.01 sec) mysql> ALTER TABLE ibtest11c DROP FOREIGN KEY `0_38775`; You cannot add a foreign key and drop a foreign key in separate clauses of a single *Note `ALTER TABLE': alter-table. statement. Separate statements are required. If *Note `ALTER TABLE': alter-table. for an `InnoDB' table results in changes to column values (for example, because a column is truncated), `InnoDB''s `FOREIGN KEY' constraint checks do not notice possible violations caused by changing the values. The `InnoDB' parser permits table and column identifiers in a `FOREIGN KEY ... REFERENCES ...' clause to be quoted within backticks. (Alternatively, double quotation marks can be used if the `ANSI_QUOTES' SQL mode is enabled.) The `InnoDB' parser also takes into account the setting of the `lower_case_table_names' system variable. `InnoDB' returns a table's foreign key definitions as part of the output of the *Note `SHOW CREATE TABLE': show-create-table. statement: SHOW CREATE TABLE TBL_NAME; *Note `mysqldump': mysqldump. also produces correct definitions of tables in the dump file, and does not forget about the foreign keys. When performing foreign key checks, `InnoDB' sets shared row-level locks on child or parent records it has to look at. `InnoDB' checks foreign key constraints immediately; the check is not deferred to transaction commit. To make it easier to reload dump files for tables that have foreign key relationships, *Note `mysqldump': mysqldump. automatically includes a statement in the dump output to set `foreign_key_checks' to 0. This avoids problems with tables having to be reloaded in a particular order when the dump is reloaded. It is also possible to set this variable manually: mysql> SET foreign_key_checks = 0; mysql> SOURCE DUMP_FILE_NAME; mysql> SET foreign_key_checks = 1; This enables you to import the tables in any order if the dump file contains tables that are not correctly ordered for foreign keys. It also speeds up the import operation. Setting `foreign_key_checks' to 0 can also be useful for ignoring foreign key constraints during *Note `LOAD DATA': load-data. and *Note `ALTER TABLE': alter-table. operations. However, even if `foreign_key_checks = 0', InnoDB does not permit the creation of a foreign key constraint where a column references a nonmatching column type. Also, if an `InnoDB' table has foreign key constraints, *Note `ALTER TABLE': alter-table. cannot be used to change the table to use another storage engine. To alter the storage engine, drop any foreign key constraints first. `InnoDB' does not permit you to drop a table that is referenced by a `FOREIGN KEY' constraint, unless you do `SET foreign_key_checks = 0'. When you drop a table, the constraints that were defined in its create statement are also dropped. If you re-create a table that was dropped, it must have a definition that conforms to the foreign key constraints referencing it. It must have the right column names and types, and it must have indexes on the referenced keys, as stated earlier. If these are not satisfied, MySQL returns error number 1005 and refers to error 150 in the error message. If MySQL reports an error number 1005 from a *Note `CREATE TABLE': create-table. statement, and the error message refers to error 150, table creation failed because a foreign key constraint was not correctly formed. Similarly, if an *Note `ALTER TABLE': alter-table. fails and it refers to error 150, that means a foreign key definition would be incorrectly formed for the altered table. You can use *Note `SHOW ENGINE INNODB STATUS': show-engine. to display a detailed explanation of the most recent `InnoDB' foreign key error in the server. *Important*: For users familiar with the ANSI/ISO SQL Standard, please note that no storage engine, including `InnoDB', recognizes or enforces the `MATCH' clause used in referential-integrity constraint definitions. Use of an explicit `MATCH' clause will not have the specified effect, and also causes `ON DELETE' and `ON UPDATE' clauses to be ignored. For these reasons, specifying `MATCH' should be avoided. The `MATCH' clause in the SQL standard controls how `NULL' values in a composite (multiple-column) foreign key are handled when comparing to a primary key. `InnoDB' essentially implements the semantics defined by `MATCH SIMPLE', which permit a foreign key to be all or partially `NULL'. In that case, the (child table) row containing such a foreign key is permitted to be inserted, and does not match any row in the referenced (parent) table. It is possible to implement other semantics using triggers. Additionally, MySQL and `InnoDB' require that the referenced columns be indexed for performance. However, the system does not enforce a requirement that the referenced columns be `UNIQUE' or be declared `NOT NULL'. The handling of foreign key references to nonunique keys or keys that contain `NULL' values is not well defined for operations such as *Note `UPDATE': update. or `DELETE CASCADE'. You are advised to use foreign keys that reference only `UNIQUE' and `NOT NULL' keys. Furthermore, `InnoDB' does not recognize or support `inline `REFERENCES' specifications' (as defined in the SQL standard) where the references are defined as part of the column specification. `InnoDB' accepts `REFERENCES' clauses only when specified as part of a separate `FOREIGN KEY' specification. For other storage engines, MySQL Server parses and ignores foreign key specifications. *Deviation from SQL standards*: If there are several rows in the parent table that have the same referenced key value, `InnoDB' acts in foreign key checks as if the other parent rows with the same key value do not exist. For example, if you have defined a `RESTRICT' type constraint, and there is a child row with several parent rows, `InnoDB' does not permit the deletion of any of those parent rows. `InnoDB' performs cascading operations through a depth-first algorithm, based on records in the indexes corresponding to the foreign key constraints. *Deviation from SQL standards*: A `FOREIGN KEY' constraint that references a non-`UNIQUE' key is not standard SQL. It is an `InnoDB' extension to standard SQL. *Deviation from SQL standards*: If `ON UPDATE CASCADE' or `ON UPDATE SET NULL' recurses to update the _same table_ it has previously updated during the cascade, it acts like `RESTRICT'. This means that you cannot use self-referential `ON UPDATE CASCADE' or `ON UPDATE SET NULL' operations. This is to prevent infinite loops resulting from cascaded updates. A self-referential `ON DELETE SET NULL', on the other hand, is possible, as is a self-referential `ON DELETE CASCADE'. Cascading operations may not be nested more than 15 levels deep. *Deviation from SQL standards*: Like MySQL in general, in an SQL statement that inserts, deletes, or updates many rows, `InnoDB' checks `UNIQUE' and `FOREIGN KEY' constraints row-by-row. According to the SQL standard, the default behavior should be deferred checking. That is, constraints are only checked after the _entire SQL statement_ has been processed. Until `InnoDB' implements deferred constraint checking, some things will be impossible, such as deleting a record that refers to itself using a foreign key.  File: manual.info, Node: innodb-and-mysql-replication, Prev: innodb-foreign-key-constraints, Up: using-innodb-tables 14.6.4.7 `InnoDB' and MySQL Replication ....................................... MySQL replication works for `InnoDB' tables as it does for `MyISAM' tables. It is also possible to use replication in a way where the storage engine on the slave is not the same as the original storage engine on the master. For example, you can replicate modifications to an `InnoDB' table on the master to a `MyISAM' table on the slave. To set up a new slave for a master, you have to make a copy of the `InnoDB' tablespace and the log files, as well as the `.frm' files of the `InnoDB' tables, and move the copies to the slave. If the `innodb_file_per_table' variable is enabled, copy the `.ibd' files as well. For the proper procedure to do this, see *Note innodb-backup::. If you can shut down the master or an existing slave, you can take a cold backup of the `InnoDB' tablespace and log files and use that to set up a slave. To make a new slave without taking down any server you can also use the commercial `InnoDB' Hot Backup tool (http://www.innodb.com/wp/products/hot-backup/). You cannot set up replication for `InnoDB' using the *Note `LOAD TABLE FROM MASTER': load-table-from-master. statement, which works only for `MyISAM' tables. There are two possible workarounds: * Dump the table on the master and import the dump file into the slave. * Use `ALTER TABLE TBL_NAME ENGINE=MyISAM' on the master before setting up replication with `LOAD TABLE TBL_NAME FROM MASTER', and then use *Note `ALTER TABLE': alter-table. to convert the master table back to `InnoDB' afterward. However, this should not be done for tables that have foreign key definitions because the definitions will be lost. Transactions that fail on the master do not affect replication at all. MySQL replication is based on the binary log where MySQL writes SQL statements that modify data. A transaction that fails (for example, because of a foreign key violation, or because it is rolled back) is not written to the binary log, so it is not sent to slaves. See *Note commit::. Replication and `CASCADE' Cascading actions for `InnoDB' tables on the master are replicated on the slave _only_ if the tables sharing the foreign key relation use `InnoDB' on both the master and slave. This is true whether you are using statement-based or row-based replication. Suppose that you have started replication, and then create two tables on the master using the following *Note `CREATE TABLE': create-table. statements: CREATE TABLE fc1 ( i INT PRIMARY KEY, j INT ) ENGINE = InnoDB; CREATE TABLE fc2 ( m INT PRIMARY KEY, n INT, FOREIGN KEY ni (n) REFERENCES fc1 (i) ON DELETE CASCADE ) ENGINE = InnoDB; Suppose that the slave does not have `InnoDB' support enabled. If this is the case, then the tables on the slave are created, but they use the `MyISAM' storage engine, and the `FOREIGN KEY' option is ignored. Now we insert some rows into the tables on the master: master> INSERT INTO fc1 VALUES (1, 1), (2, 2); Query OK, 2 rows affected (0.09 sec) Records: 2 Duplicates: 0 Warnings: 0 master> INSERT INTO fc2 VALUES (1, 1), (2, 2), (3, 1); Query OK, 3 rows affected (0.19 sec) Records: 3 Duplicates: 0 Warnings: 0 At this point, on both the master and the slave, table `fc1' contains 2 rows, and table `fc2' contains 3 rows, as shown here: master> SELECT * FROM fc1; +---+------+ | i | j | +---+------+ | 1 | 1 | | 2 | 2 | +---+------+ 2 rows in set (0.00 sec) master> SELECT * FROM fc2; +---+------+ | m | n | +---+------+ | 1 | 1 | | 2 | 2 | | 3 | 1 | +---+------+ 3 rows in set (0.00 sec) slave> SELECT * FROM fc1; +---+------+ | i | j | +---+------+ | 1 | 1 | | 2 | 2 | +---+------+ 2 rows in set (0.00 sec) slave> SELECT * FROM fc2; +---+------+ | m | n | +---+------+ | 1 | 1 | | 2 | 2 | | 3 | 1 | +---+------+ 3 rows in set (0.00 sec) Now suppose that you perform the following *Note `DELETE': delete. statement on the master: master> DELETE FROM fc1 WHERE i=1; Query OK, 1 row affected (0.09 sec) Due to the cascade, table `fc2' on the master now contains only 1 row: master> SELECT * FROM fc2; +---+---+ | m | n | +---+---+ | 2 | 2 | +---+---+ 1 row in set (0.00 sec) However, the cascade does not propagate on the slave because on the slave the *Note `DELETE': delete. for `fc1' deletes no rows from `fc2'. The slave's copy of `fc2' still contains all of the rows that were originally inserted: slave> SELECT * FROM fc2; +---+---+ | m | n | +---+---+ | 1 | 1 | | 3 | 1 | | 2 | 2 | +---+---+ 3 rows in set (0.00 sec) This difference is due to the fact that the cascading deletes are handled internally by the `InnoDB' storage engine, which means that none of the changes are logged.  File: manual.info, Node: innodb-data-log-reconfiguration, Next: innodb-backup, Prev: using-innodb-tables, Up: innodb-storage-engine 14.6.5 Adding, Removing, or Resizing `InnoDB' Data and Log Files ---------------------------------------------------------------- This section describes what you can do when your `InnoDB' tablespace runs out of room or when you want to change the size of the log files. The easiest way to increase the size of the `InnoDB' tablespace is to configure it from the beginning to be auto-extending. Specify the `autoextend' attribute for the last data file in the tablespace definition. Then `InnoDB' increases the size of that file automatically in 8MB increments when it runs out of space. The increment size can be changed by setting the value of the `innodb_autoextend_increment' system variable, which is measured in MB. Alternatively, you can increase the size of your tablespace by adding another data file. To do this, you have to shut down the MySQL server, change the tablespace configuration to add a new data file to the end of `innodb_data_file_path', and start the server again. If your last data file was defined with the keyword `autoextend', the procedure for reconfiguring the tablespace must take into account the size to which the last data file has grown. Obtain the size of the data file, round it down to the closest multiple of 1024 x 1024 bytes (= 1MB), and specify the rounded size explicitly in `innodb_data_file_path'. Then you can add another data file. Remember that only the last data file in the `innodb_data_file_path' can be specified as auto-extending. As an example, assume that the tablespace has just one auto-extending data file `ibdata1': innodb_data_home_dir = innodb_data_file_path = /ibdata/ibdata1:10M:autoextend Suppose that this data file, over time, has grown to 988MB. Here is the configuration line after modifying the original data file to not be auto-extending and adding another auto-extending data file: innodb_data_home_dir = innodb_data_file_path = /ibdata/ibdata1:988M;/disk2/ibdata2:50M:autoextend When you add a new file to the tablespace configuration, make sure that it does not exist. `InnoDB' will create and initialize the file when you restart the server. Currently, you cannot remove a data file from the tablespace. To decrease the size of your tablespace, use this procedure: 1. Use *Note `mysqldump': mysqldump. to dump all your `InnoDB' tables. 2. Stop the server. 3. Remove all the existing tablespace files, including the `ibdata' and `ib_log' files. If you want to keep a backup copy of the information, then copy all the `ib*' files to another location before the removing the files in your MySQL installation. 4. Remove any `.frm' files for `InnoDB' tables. 5. Configure a new tablespace. 6. Restart the server. 7. Import the dump files. If you want to change the number or the size of your `InnoDB' log files, use the following instructions. The procedure to use depends on the value of `innodb_fast_shutdown': * If `innodb_fast_shutdown' is not set to 2: Stop the MySQL server and make sure that it shuts down without errors (to ensure that there is no information for outstanding transactions in the log). Copy the old log files into a safe place in case something went wrong during the shutdown and you need them to recover the tablespace. Delete the old log files from the log file directory, edit `my.cnf' to change the log file configuration, and start the MySQL server again. *Note `mysqld': mysqld. sees that no *Note `InnoDB': innodb-storage-engine. log files exist at startup and creates new ones. * If `innodb_fast_shutdown' is set to 2: Set `innodb_fast_shutdown' to 1: mysql> SET GLOBAL innodb_fast_shutdown = 1; Then follow the instructions in the previous item.  File: manual.info, Node: innodb-backup, Next: innodb-migration, Prev: innodb-data-log-reconfiguration, Up: innodb-storage-engine 14.6.6 Backing Up and Recovering an `InnoDB' Database ----------------------------------------------------- * Menu: * innodb-recovery:: The `InnoDB' Recovery Process * forcing-innodb-recovery:: Forcing `InnoDB' Recovery * innodb-checkpoints:: `InnoDB' Checkpoints The key to safe database management is making regular backups. `InnoDB Hot Backup' enables you to back up a running MySQL database, including *Note `InnoDB': innodb-storage-engine. and *Note `MyISAM': myisam-storage-engine. tables, with minimal disruption to operations while producing a consistent snapshot of the database. When `InnoDB Hot Backup' is copying *Note `InnoDB': innodb-storage-engine. tables, reads and writes to both *Note `InnoDB': innodb-storage-engine. and *Note `MyISAM': myisam-storage-engine. tables can continue. During the copying of *Note `MyISAM': myisam-storage-engine. tables, reads (but not writes) to those tables are permitted. In addition, `InnoDB Hot Backup' supports creating compressed backup files, and performing backups of subsets of *Note `InnoDB': innodb-storage-engine. tables. In conjunction with MySQL's binary log, users can perform point-in-time recovery. `InnoDB Hot Backup' is commercially licensed by Innobase Oy. For a more complete description of `InnoDB Hot Backup', see `http://www.innodb.com/products/hot-backup/features/' or download the documentation from `http://www.innodb.com/doc/hot_backup/manual.html'. You can order trial, term, and perpetual licenses from Innobase at `http://www.innodb.com/wp/products/hot-backup/order/'. If you are able to shut down your MySQL server, you can make a binary backup that consists of all files used by *Note `InnoDB': innodb-storage-engine. to manage its tables. Use the following procedure: 1. Shut down the MySQL server and make sure that it stops without errors. 2. Copy all *Note `InnoDB': innodb-storage-engine. data files (`ibdata' files and `.ibd' files) into a safe place. 3. Copy all the `.frm' files for *Note `InnoDB': innodb-storage-engine. tables to a safe place. 4. Copy all *Note `InnoDB': innodb-storage-engine. log files (`ib_logfile' files) to a safe place. 5. Copy your `my.cnf' configuration file or files to a safe place. In addition to making binary backups as just described, regularly make dumps of your tables with *Note `mysqldump': mysqldump. A binary file might be corrupted without you noticing it. Dumped tables are stored into text files that are human-readable, so spotting table corruption becomes easier. Also, because the format is simpler, the chance for serious data corruption is smaller. *Note `mysqldump': mysqldump. also has a `--single-transaction' option for making a consistent snapshot without locking out other clients. See *Note backup-policy::. Replication works with *Note `InnoDB': innodb-storage-engine. tables, so you can use MySQL replication capabilities to keep a copy of your database at database sites requiring high availability. To be able to recover your *Note `InnoDB': innodb-storage-engine. database to the present from the time at which the binary backup was made, run your MySQL server with binary logging turned on. To achieve point-in-time recovery after restoring a backup, you can apply changes from the binary log that occurred after the backup was made. See *Note point-in-time-recovery::. To recover from a crash of your MySQL server, the only requirement is to restart it. *Note `InnoDB': innodb-storage-engine. automatically checks the logs and performs a roll-forward of the database to the present. *Note `InnoDB': innodb-storage-engine. automatically rolls back uncommitted transactions that were present at the time of the crash. During recovery, *Note `mysqld': mysqld. displays output something like this: InnoDB: Database was not shut down normally. InnoDB: Starting recovery from log files... InnoDB: Starting log scan based on checkpoint at InnoDB: log sequence number 0 13674004 InnoDB: Doing recovery: scanned up to log sequence number 0 13739520 InnoDB: Doing recovery: scanned up to log sequence number 0 13805056 InnoDB: Doing recovery: scanned up to log sequence number 0 13870592 InnoDB: Doing recovery: scanned up to log sequence number 0 13936128 ... InnoDB: Doing recovery: scanned up to log sequence number 0 20555264 InnoDB: Doing recovery: scanned up to log sequence number 0 20620800 InnoDB: Doing recovery: scanned up to log sequence number 0 20664692 InnoDB: 1 uncommitted transaction(s) which must be rolled back InnoDB: Starting rollback of uncommitted transactions InnoDB: Rolling back trx no 16745 InnoDB: Rolling back of trx no 16745 completed InnoDB: Rollback of uncommitted transactions completed InnoDB: Starting an apply batch of log records to the database... InnoDB: Apply batch completed InnoDB: Started mysqld: ready for connections If your database becomes corrupted or disk failure occurs, you must perform the recovery using a backup. In the case of corruption, first find a backup that is not corrupted. After restoring the base backup, do a point-in-time recovery from the binary log files using *Note `mysqlbinlog': mysqlbinlog. and *Note `mysql': mysql. to restore the changes that occurred after the backup was made. In some cases of database corruption it is enough just to dump, drop, and re-create one or a few corrupt tables. You can use the *Note `CHECK TABLE': check-table. SQL statement to check whether a table is corrupt, although *Note `CHECK TABLE': check-table. naturally cannot detect every possible kind of corruption. You can use the Tablespace Monitor to check the integrity of the file space management inside the tablespace files. In some cases, apparent database page corruption is actually due to the operating system corrupting its own file cache, and the data on disk may be okay. It is best first to try restarting your computer. Doing so may eliminate errors that appeared to be database page corruption.  File: manual.info, Node: innodb-recovery, Next: forcing-innodb-recovery, Prev: innodb-backup, Up: innodb-backup 14.6.6.1 The `InnoDB' Recovery Process ...................................... `InnoDB' crash recovery consists of several steps. The first step, redo log application, is performed during the initialization, before accepting any connections. If all changes were flushed from the buffer pool to the tablespaces (`ibdata*' and `*.ibd' files) at the time of the shutdown or crash, the redo log application can be skipped. If the redo log files are missing at startup, `InnoDB' skips the redo log application. The remaining steps after redo log application do not depend on the redo log (other than for logging the writes) and are performed in parallel with normal processing. These include: * Rolling back incomplete transactions: Any transactions that were active at the time of crash or fast shutdown. * Insert buffer merge: Applying changes from the insert buffer tree (from the shared tablespace) to leaf pages of secondary indexes as the index pages are read to the buffer pool. * Purge: Deleting delete-marked records that are no longer visible for any active transaction. Of these, only rollback of incomplete transactions is special to crash recovery. The insert buffer merge and the purge are performed during normal processing.  File: manual.info, Node: forcing-innodb-recovery, Next: innodb-checkpoints, Prev: innodb-recovery, Up: innodb-backup 14.6.6.2 Forcing `InnoDB' Recovery .................................. If there is database page corruption, you may want to dump your tables from the database with `SELECT INTO ... OUTFILE'. Usually, most of the data obtained in this way is intact. However, it is possible that the corruption might cause `SELECT * FROM TBL_NAME' statements or `InnoDB' background operations to crash or assert, or even cause `InnoDB' roll-forward recovery to crash. In such cases, you can use the `innodb_force_recovery' option to force the `InnoDB' storage engine to start up while preventing background operations from running, so that you are able to dump your tables. For example, you can add the following line to the `[mysqld]' section of your option file before restarting the server: [mysqld] innodb_force_recovery = 4 `innodb_force_recovery' is 0 by default (normal startup without forced recovery) The permissible nonzero values for `innodb_force_recovery' follow. A larger number includes all precautions of smaller numbers. If you are able to dump your tables with an option value of at most 4, then you are relatively safe that only some data on corrupt individual pages is lost. A value of 6 is more drastic because database pages are left in an obsolete state, which in turn may introduce more corruption into B-trees and other database structures. * `1' (`SRV_FORCE_IGNORE_CORRUPT') Let the server run even if it detects a corrupt page. Try to make `SELECT * FROM TBL_NAME' jump over corrupt index records and pages, which helps in dumping tables. * `2' (`SRV_FORCE_NO_BACKGROUND') Prevent the main thread from running. If a crash would occur during the purge operation, this recovery value prevents it. * `3' (`SRV_FORCE_NO_TRX_UNDO') Do not run transaction rollbacks after recovery. * `4' (`SRV_FORCE_NO_IBUF_MERGE') Prevent insert buffer merge operations. If they would cause a crash, do not do them. Do not calculate table statistics. * `5' (`SRV_FORCE_NO_UNDO_LOG_SCAN') Do not look at undo logs when starting the database: `InnoDB' treats even incomplete transactions as committed. * `6' (`SRV_FORCE_NO_LOG_REDO') Do not do the log roll-forward in connection with recovery. _The database must not otherwise be used with any nonzero value of `innodb_force_recovery'_. As a safety measure, `InnoDB' prevents users from performing *Note `INSERT': insert, *Note `UPDATE': update, or *Note `DELETE': delete. operations when `innodb_force_recovery' is greater than 0. You can *Note `SELECT': select. from tables to dump them, or `DROP' or `CREATE' tables even if forced recovery is used. If you know that a given table is causing a crash on rollback, you can drop it. You can also use this to stop a runaway rollback caused by a failing mass import or *Note `ALTER TABLE': alter-table. You can kill the *Note `mysqld': mysqld. process and set `innodb_force_recovery' to `3' to bring the database up without the rollback, then `DROP' the table that is causing the runaway rollback.  File: manual.info, Node: innodb-checkpoints, Prev: forcing-innodb-recovery, Up: innodb-backup 14.6.6.3 `InnoDB' Checkpoints ............................. `InnoDB' implements a checkpoint mechanism known as `fuzzy' checkpointing. `InnoDB' flushes modified database pages from the buffer pool in small batches. There is no need to flush the buffer pool in one single batch, which would in practice stop processing of user SQL statements during the checkpointing process. During crash recovery, `InnoDB' looks for a checkpoint label written to the log files. It knows that all modifications to the database before the label are present in the disk image of the database. Then `InnoDB' scans the log files forward from the checkpoint, applying the logged modifications to the database. `InnoDB' writes to its log files on a rotating basis. It also writes checkpoint information to the first log file at each checkpoint. All committed modifications that make the database pages in the buffer pool different from the images on disk must be available in the log files in case `InnoDB' has to do a recovery. This means that when `InnoDB' starts to reuse a log file, it has to make sure that the database page images on disk contain the modifications logged in the log file that `InnoDB' is going to reuse. In other words, `InnoDB' must create a checkpoint and this often involves flushing of modified database pages to disk. The preceding description explains why making your log files very large may reduce disk I/O in checkpointing. It often makes sense to set the total size of the log files as large as the buffer pool or even larger. The disadvantage of using large log files is that crash recovery can take longer because there is more logged information to apply to the database.  File: manual.info, Node: innodb-migration, Next: innodb-transaction-model, Prev: innodb-backup, Up: innodb-storage-engine 14.6.7 Moving an `InnoDB' Database to Another Machine ----------------------------------------------------- On Windows, `InnoDB' always stores database and table names internally in lowercase. To move databases in a binary format from Unix to Windows or from Windows to Unix, create all databases and tables using lowercase names. A convenient way to accomplish this is to add the following line to the `[mysqld]' section of your `my.cnf' or `my.ini' file before creating any databases or tables: [mysqld] lower_case_table_names=1 Like `MyISAM' data files, `InnoDB' data and log files are binary-compatible on all platforms having the same floating-point number format. You can move an `InnoDB' database simply by copying all the relevant files listed in *Note innodb-backup::. If the floating-point formats differ but you have not used *Note `FLOAT': numeric-types. or *Note `DOUBLE': numeric-types. data types in your tables, then the procedure is the same: simply copy the relevant files. If you use *Note `mysqldump': mysqldump. to dump your tables on one machine and then import the dump files on the other machine, it does not matter whether the formats differ or your tables contain floating-point data. One way to increase performance is to switch off autocommit mode when importing data, assuming that the tablespace has enough space for the big rollback segment that the import transactions generate. Do the commit only after importing a whole table or a segment of a table.  File: manual.info, Node: innodb-transaction-model, Next: innodb-multi-versioning, Prev: innodb-migration, Up: innodb-storage-engine 14.6.8 The `InnoDB' Transaction Model and Locking ------------------------------------------------- * Menu: * innodb-lock-modes:: `InnoDB' Lock Modes * innodb-consistent-read:: Consistent Nonlocking Reads * innodb-locking-reads:: `SELECT ... FOR UPDATE' and `SELECT ... LOCK IN SHARE MODE' Locking Reads * innodb-record-level-locks:: `InnoDB' Record, Gap, and Next-Key Locks * innodb-next-key-locking:: Avoiding the Phantom Problem Using Next-Key Locking * innodb-locks-set:: Locks Set by Different SQL Statements in `InnoDB' * innodb-implicit-commit:: Implicit Transaction Commit and Rollback * innodb-deadlock-detection:: Deadlock Detection and Rollback * innodb-deadlocks:: How to Cope with Deadlocks In the `InnoDB' transaction model, the goal is to combine the best properties of a multi-versioning database with traditional two-phase locking. `InnoDB' does locking on the row level and runs queries as nonlocking consistent reads by default, in the style of Oracle. The lock table in `InnoDB' is stored so space-efficiently that lock escalation is not needed: Typically, several users are permitted to lock every row in `InnoDB' tables, or any random subset of the rows, without causing `InnoDB' memory exhaustion. In `InnoDB', all user activity occurs inside a transaction. If autocommit mode is enabled, each SQL statement forms a single transaction on its own. By default, MySQL starts the session for each new connection with autocommit enabled, so MySQL does a commit after each SQL statement if that statement did not return an error. If a statement returns an error, the commit or rollback behavior depends on the error. See *Note innodb-error-handling::. A session that has autocommit enabled can perform a multiple-statement transaction by starting it with an explicit *Note `START TRANSACTION': commit. or *Note `BEGIN': commit. statement and ending it with a *Note `COMMIT': commit. or *Note `ROLLBACK': commit. statement. See *Note commit::. If autocommit mode is disabled within a session with `SET autocommit = 0', the session always has a transaction open. A *Note `COMMIT': commit. or *Note `ROLLBACK': commit. statement ends the current transaction and a new one starts. A *Note `COMMIT': commit. means that the changes made in the current transaction are made permanent and become visible to other sessions. A *Note `ROLLBACK': commit. statement, on the other hand, cancels all modifications made by the current transaction. Both *Note `COMMIT': commit. and *Note `ROLLBACK': commit. release all `InnoDB' locks that were set during the current transaction. In terms of the SQL:1992 transaction isolation levels, the default `InnoDB' level is `REPEATABLE READ'. `InnoDB' offers all four transaction isolation levels described by the SQL standard: `READ UNCOMMITTED', `READ COMMITTED', `REPEATABLE READ', and `SERIALIZABLE'. A user can change the isolation level for a single session or for all subsequent connections with the *Note `SET TRANSACTION': set-transaction. statement. To set the server's default isolation level for all connections, use the `--transaction-isolation' option on the command line or in an option file. For detailed information about isolation levels and level-setting syntax, see *Note set-transaction::. In row-level locking, `InnoDB' normally uses next-key locking. That means that besides index records, `InnoDB' can also lock the `gap' preceding an index record to block insertions by other sessions in the gap immediately before the index record. A next-key lock refers to a lock that locks an index record and the gap before it. A gap lock refers to a lock that locks only the gap before some index record. For more information about row-level locking, and the circumstances under which gap locking is disabled, see *Note innodb-record-level-locks::.  File: manual.info, Node: innodb-lock-modes, Next: innodb-consistent-read, Prev: innodb-transaction-model, Up: innodb-transaction-model 14.6.8.1 `InnoDB' Lock Modes ............................ `InnoDB' implements standard row-level locking where there are two types of locks: * A shared (S) lock permits a transaction to read a row. * An exclusive (X) lock permits a transaction to update or delete a row. If transaction `T1' holds a shared (S) lock on row `r', then requests from some distinct transaction `T2' for a lock on row `r' are handled as follows: * A request by `T2' for an S lock can be granted immediately. As a result, both `T1' and `T2' hold an S lock on `r'. * A request by `T2' for an X lock cannot be granted immediately. If a transaction `T1' holds an exclusive (X) lock on row `r', a request from some distinct transaction `T2' for a lock of either type on `r' cannot be granted immediately. Instead, transaction `T2' has to wait for transaction `T1' to release its lock on row `r'. Additionally, `InnoDB' supports _multiple granularity locking_ which permits coexistence of record locks and locks on entire tables. To make locking at multiple granularity levels practical, additional types of locks called _intention locks_ are used. Intention locks are table locks in `InnoDB'. The idea behind intention locks is for a transaction to indicate which type of lock (shared or exclusive) it will require later for a row in that table. There are two types of intention locks used in `InnoDB' (assume that transaction `T' has requested a lock of the indicated type on table `t'): * Intention shared (IS): Transaction `T' intends to set S locks on individual rows in table `t'. * Intention exclusive (IX): Transaction `T' intends to set X locks on those rows. For example, *Note `SELECT ... LOCK IN SHARE MODE': select. sets an IS lock and *Note `SELECT ... FOR UPDATE': select. sets an IX lock. The intention locking protocol is as follows: * Before a transaction can acquire an S lock on a row in table `t', it must first acquire an IS or stronger lock on `t'. * Before a transaction can acquire an X lock on a row, it must first acquire an IX lock on `t'. These rules can be conveniently summarized by means of the following _lock type compatibility matrix_. X IX S IS X Conflict Conflict Conflict Conflict IX Conflict Compatible Conflict Compatible S Conflict Conflict Compatible Compatible IS Conflict Compatible Compatible Compatible A lock is granted to a requesting transaction if it is compatible with existing locks, but not if it conflicts with existing locks. A transaction waits until the conflicting existing lock is released. If a lock request conflicts with an existing lock and cannot be granted because it would cause deadlock, an error occurs. Thus, intention locks do not block anything except full table requests (for example, `LOCK TABLES ... WRITE'). The main purpose of IX and IS locks is to show that someone is locking a row, or going to lock a row in the table. The following example illustrates how an error can occur when a lock request would cause a deadlock. The example involves two clients, A and B. First, client A creates a table containing one row, and then begins a transaction. Within the transaction, A obtains an S lock on the row by selecting it in share mode: mysql> CREATE TABLE t (i INT) ENGINE = InnoDB; Query OK, 0 rows affected (1.07 sec) mysql> INSERT INTO t (i) VALUES(1); Query OK, 1 row affected (0.09 sec) mysql> START TRANSACTION; Query OK, 0 rows affected (0.00 sec) mysql> SELECT * FROM t WHERE i = 1 LOCK IN SHARE MODE; +------+ | i | +------+ | 1 | +------+ 1 row in set (0.10 sec) Next, client B begins a transaction and attempts to delete the row from the table: mysql> START TRANSACTION; Query OK, 0 rows affected (0.00 sec) mysql> DELETE FROM t WHERE i = 1; The delete operation requires an X lock. The lock cannot be granted because it is incompatible with the S lock that client A holds, so the request goes on the queue of lock requests for the row and client B blocks. Finally, client A also attempts to delete the row from the table: mysql> DELETE FROM t WHERE i = 1; ERROR 1213 (40001): Deadlock found when trying to get lock; try restarting transaction Deadlock occurs here because client A needs an X lock to delete the row. However, that lock request cannot be granted because client B already has a request for an X lock and is waiting for client A to release its S lock. Nor can the S lock held by A be upgraded to an X lock because of the prior request by B for an X lock. As a result, `InnoDB' generates an error for client A and releases its locks. At that point, the lock request for client B can be granted and B deletes the row from the table.  File: manual.info, Node: innodb-consistent-read, Next: innodb-locking-reads, Prev: innodb-lock-modes, Up: innodb-transaction-model 14.6.8.2 Consistent Nonlocking Reads .................................... A consistent read means that `InnoDB' uses multi-versioning to present to a query a snapshot of the database at a point in time. The query sees the changes made by transactions that committed before that point of time, and no changes made by later or uncommitted transactions. The exception to this rule is that the query sees the changes made by earlier statements within the same transaction. This exception causes the following anomaly: If you update some rows in a table, a *Note `SELECT': select. sees the latest version of the updated rows, but it might also see older versions of any rows. If other sessions simultaneously update the same table, the anomaly means that you might see the table in a state that never existed in the database. If the transaction isolation level is `REPEATABLE READ' (the default level), all consistent reads within the same transaction read the snapshot established by the first such read in that transaction. You can get a fresher snapshot for your queries by committing the current transaction and after that issuing new queries. With `READ COMMITTED' isolation level, each consistent read within a transaction sets and reads its own fresh snapshot. Consistent read is the default mode in which `InnoDB' processes *Note `SELECT': select. statements in `READ COMMITTED' and `REPEATABLE READ' isolation levels. A consistent read does not set any locks on the tables it accesses, and therefore other sessions are free to modify those tables at the same time a consistent read is being performed on the table. Suppose that you are running in the default `REPEATABLE READ' isolation level. When you issue a consistent read (that is, an ordinary *Note `SELECT': select. statement), `InnoDB' gives your transaction a timepoint according to which your query sees the database. If another transaction deletes a row and commits after your timepoint was assigned, you do not see the row as having been deleted. Inserts and updates are treated similarly. You can advance your timepoint by committing your transaction and then doing another *Note `SELECT': select. This is called _multi-versioned concurrency control_. In the following example, session A sees the row inserted by B only when B has committed the insert and A has committed as well, so that the timepoint is advanced past the commit of B. Session A Session B SET autocommit=0; SET autocommit=0; time | SELECT * FROM t; | empty set | INSERT INTO t VALUES (1, 2); | v SELECT * FROM t; empty set COMMIT; SELECT * FROM t; empty set COMMIT; SELECT * FROM t; --------------------- | 1 | 2 | --------------------- 1 row in set If you want to see the `freshest' state of the database, use either the `READ COMMITTED' isolation level or a locking read: SELECT * FROM t LOCK IN SHARE MODE; With `READ COMMITTED' isolation level, each consistent read within a transaction sets and reads its own fresh snapshot. With `LOCK IN SHARE MODE', a locking read occurs instead: A `SELECT' blocks until the transaction containing the freshest rows ends (see *Note innodb-locking-reads::). Consistent read does not work over certain DDL statements: * Consistent read does not work over *Note `DROP TABLE': drop-table, because MySQL cannot use a table that has been dropped and `InnoDB' destroys the table. * Consistent read does not work over *Note `ALTER TABLE': alter-table, because that statement makes a temporary copy of the original table and deletes the original table when the temporary copy is built. When you reissue a consistent read within a transaction, rows in the new table are not visible because those rows did not exist when the transaction's snapshot was taken. `InnoDB' uses a consistent read for select in clauses like *Note `INSERT INTO ... SELECT': insert, *Note `UPDATE ... (SELECT)': update, and *Note `CREATE TABLE ... SELECT': create-table. that do not specify `FOR UPDATE' or `LOCK IN SHARE MODE' if the `innodb_locks_unsafe_for_binlog' option is set and the isolation level of the transaction is not set to `SERIALIZABLE'. Thus, no locks are set on rows read from the selected table. Otherwise, `InnoDB' uses stronger locks and the *Note `SELECT': select. part acts like `READ COMMITTED', where each consistent read, even within the same transaction, sets and reads its own fresh snapshot.  File: manual.info, Node: innodb-locking-reads, Next: innodb-record-level-locks, Prev: innodb-consistent-read, Up: innodb-transaction-model 14.6.8.3 `SELECT ... FOR UPDATE' and `SELECT ... LOCK IN SHARE MODE' Locking Reads .................................................................................. If you query data and then insert or update related data within the same transaction, the regular `SELECT' statement does not give enough protection. Other transactions can update or delete the same rows you just queried. `InnoDB' supports two types of locking reads that offer extra safety: * *Note `SELECT ... LOCK IN SHARE MODE': select. sets a shared mode lock on any rows that are read. Other sessions can read the rows, but cannot modify them until your transaction commits. If any of these rows were changed by another transaction that has not yet committed, your query waits until that transaction ends and then uses the latest values. * *Note `SELECT ... FOR UPDATE': select. locks the rows and any associated index entries, the same as if you issued an `UPDATE' statement for those rows. Other transactions are blocked from updating those rows, from doing *Note `SELECT ... LOCK IN SHARE MODE': select, or from reading the data in certain transaction isolation levels. Consistent reads ignore any locks set on the records that exist in the read view. (Old versions of a record cannot be locked; they are reconstructed by applying undo logs on an in-memory copy of the record.) These clauses are primarily useful when dealing with tree-structured or graph-structured data, either in a single table or split across multiple tables. All locks set by `LOCK IN SHARE MODE' and `FOR UPDATE' reads are released when the transaction is committed or rolled back. *Note*: Locking of rows for update using `SELECT FOR UPDATE' only applies when autocommit is disabled (either by beginning transaction with *Note `START TRANSACTION': commit. or by setting `autocommit' to 0. If autocommit is enabled, the rows matching the specification are not locked. * Usage Examples * Suppose that you want to insert a new row into a table `child', and make sure that the child row has a parent row in table `parent'. Your application code can ensure referential integrity throughout this sequence of operations. First, use a consistent read to query the table `PARENT' and verify that the parent row exists. Can you safely insert the child row to table `CHILD'? No, because some other session could delete the parent row in the moment between your `SELECT' and your `INSERT', without you being aware of it. To avoid this potential issue, perform the *Note `SELECT': select. using `LOCK IN SHARE MODE': SELECT * FROM parent WHERE NAME = 'Jones' LOCK IN SHARE MODE; After the `LOCK IN SHARE MODE' query returns the parent `'Jones'', you can safely add the child record to the `CHILD' table and commit the transaction. Any transaction that tries to read or write to the applicable row in the `PARENT' table waits until you are finished, that is, the data in all tables is in a consistent state. For another example, consider an integer counter field in a table `CHILD_CODES', used to assign a unique identifier to each child added to table `CHILD'. Do not use either consistent read or a shared mode read to read the present value of the counter, because two users of the database could see the same value for the counter, and a duplicate-key error occurs if two transactions attempt to add rows with the same identifier to the `CHILD' table. Here, `LOCK IN SHARE MODE' is not a good solution because if two users read the counter at the same time, at least one of them ends up in deadlock when it attempts to update the counter. Here are two ways to implement reading and incrementing the counter without interference from another transaction: * First update the counter by incrementing it by 1, then read it and use the new value in the `CHILD' table. Any other transaction that tries to read the counter waits until your transaction commits. If another transaction is in the middle of this same sequence, your transaction waits until the other one commits. * First perform a locking read of the counter using `FOR UPDATE', and then increment the counter: SELECT counter_field FROM child_codes FOR UPDATE; UPDATE child_codes SET counter_field = counter_field + 1; A *Note `SELECT ... FOR UPDATE': select. reads the latest available data, setting exclusive locks on each row it reads. Thus, it sets the same locks a searched SQL *Note `UPDATE': update. would set on the rows. The preceding description is merely an example of how *Note `SELECT ... FOR UPDATE': select. works. In MySQL, the specific task of generating a unique identifier actually can be accomplished using only a single access to the table: UPDATE child_codes SET counter_field = LAST_INSERT_ID(counter_field + 1); SELECT LAST_INSERT_ID(); The *Note `SELECT': select. statement merely retrieves the identifier information (specific to the current connection). It does not access any table.  File: manual.info, Node: innodb-record-level-locks, Next: innodb-next-key-locking, Prev: innodb-locking-reads, Up: innodb-transaction-model 14.6.8.4 `InnoDB' Record, Gap, and Next-Key Locks ................................................. `InnoDB' has several types of record-level locks: * Record lock: This is a lock on an index record. * Gap lock: This is a lock on a gap between index records, or a lock on the gap before the first or after the last index record. * Next-key lock: This is a combination of a record lock on the index record and a gap lock on the gap before the index record. Record locks always lock index records, even if a table is defined with no indexes. For such cases, `InnoDB' creates a hidden clustered index and uses this index for record locking. See *Note innodb-index-types::. By default, `InnoDB' operates in `REPEATABLE READ' transaction isolation level and with the `innodb_locks_unsafe_for_binlog' system variable disabled. In this case, `InnoDB' uses next-key locks for searches and index scans, which prevents phantom rows (see *Note innodb-next-key-locking::). Next-key locking combines index-row locking with gap locking. `InnoDB' performs row-level locking in such a way that when it searches or scans a table index, it sets shared or exclusive locks on the index records it encounters. Thus, the row-level locks are actually index-record locks. In addition, a next-key lock on an index record also affects the `gap' before that index record. That is, a next-key lock is an index-record lock plus a gap lock on the gap preceding the index record. If one session has a shared or exclusive lock on record `R' in an index, another session cannot insert a new index record in the gap immediately before `R' in the index order. Suppose that an index contains the values 10, 11, 13, and 20. The possible next-key locks for this index cover the following intervals, where `(' or `)' denote exclusion of the interval endpoint and `[' or `]' denote inclusion of the endpoint: (negative infinity, 10] (10, 11] (11, 13] (13, 20] (20, positive infinity) For the last interval, the next-key lock locks the gap above the largest value in the index and the `supremum' pseudo-record having a value higher than any value actually in the index. The supremum is not a real index record, so, in effect, this next-key lock locks only the gap following the largest index value. The preceding example shows that a gap might span a single index value, multiple index values, or even be empty. Gap locking is not needed for statements that lock rows using a unique index to search for a unique row. (This does not include the case that the search condition includes only some columns of a multiple-column unique index; in that case, gap locking does occur.) For example, if the `id' column has a unique index, the following statement uses only an index-record lock for the row having `id' value 100 and it does not matter whether other sessions insert rows in the preceding gap: SELECT * FROM child WHERE id = 100; If `id' is not indexed or has a nonunique index, the statement does lock the preceding gap. A type of gap lock called an insertion intention gap lock is set by *Note `INSERT': insert. operations prior to row insertion. This lock signals the intent to insert in such a way that multiple transactions inserting into the same index gap need not wait for each other if they are not inserting at the same position within the gap. Suppose that there are index records with values of 4 and 7. Separate transactions that attempt to insert values of 5 and 6 each lock the gap between 4 and 7 with insert intention locks prior to obtaining the exclusive lock on the inserted row, but do not block each other because the rows are nonconflicting. Gap locking can be disabled explicitly. This occurs if you change the transaction isolation level to `READ COMMITTED' or enable the `innodb_locks_unsafe_for_binlog' system variable. Under these circumstances, gap locking is disabled for searches and index scans and is used only for foreign-key constraint checking and duplicate-key checking. There are also other effects of using the `READ COMMITTED' isolation level or enabling `innodb_locks_unsafe_for_binlog': Record locks for nonmatching rows are released after MySQL has evaluated the `WHERE' condition. For `UPDATE' statements, *Note `InnoDB': innodb-storage-engine. does a `semi-consistent' read, such that it returns the latest committed version to MySQL so that MySQL can determine whether the row matches the `WHERE' condition of the *Note `UPDATE': update.  File: manual.info, Node: innodb-next-key-locking, Next: innodb-locks-set, Prev: innodb-record-level-locks, Up: innodb-transaction-model 14.6.8.5 Avoiding the Phantom Problem Using Next-Key Locking ............................................................ The so-called _phantom_ problem occurs within a transaction when the same query produces different sets of rows at different times. For example, if a *Note `SELECT': select. is executed twice, but returns a row the second time that was not returned the first time, the row is a `phantom' row. Suppose that there is an index on the `id' column of the `child' table and that you want to read and lock all rows from the table having an identifier value larger than 100, with the intention of updating some column in the selected rows later: SELECT * FROM child WHERE id > 100 FOR UPDATE; The query scans the index starting from the first record where `id' is bigger than 100. Let the table contain rows having `id' values of 90 and 102. If the locks set on the index records in the scanned range do not lock out inserts made in the gaps (in this case, the gap between 90 and 102), another session can insert a new row into the table with an `id' of 101. If you were to execute the same *Note `SELECT': select. within the same transaction, you would see a new row with an `id' of 101 (a `phantom') in the result set returned by the query. If we regard a set of rows as a data item, the new phantom child would violate the isolation principle of transactions that a transaction should be able to run so that the data it has read does not change during the transaction. To prevent phantoms, `InnoDB' uses an algorithm called _next-key locking_ that combines index-row locking with gap locking. `InnoDB' performs row-level locking in such a way that when it searches or scans a table index, it sets shared or exclusive locks on the index records it encounters. Thus, the row-level locks are actually index-record locks. In addition, a next-key lock on an index record also affects the `gap' before that index record. That is, a next-key lock is an index-record lock plus a gap lock on the gap preceding the index record. If one session has a shared or exclusive lock on record `R' in an index, another session cannot insert a new index record in the gap immediately before `R' in the index order. When `InnoDB' scans an index, it can also lock the gap after the last record in the index. Just that happens in the preceding example: To prevent any insert into the table where `id' would be bigger than 100, the locks set by `InnoDB' include a lock on the gap following `id' value 102. You can use next-key locking to implement a uniqueness check in your application: If you read your data in share mode and do not see a duplicate for a row you are going to insert, then you can safely insert your row and know that the next-key lock set on the successor of your row during the read prevents anyone meanwhile inserting a duplicate for your row. Thus, the next-key locking enables you to `lock' the nonexistence of something in your table. Gap locking can be disabled as discussed in *Note innodb-record-level-locks::. This may cause phantom problems because other sessions can insert new rows into the gaps when gap locking is disabled.  File: manual.info, Node: innodb-locks-set, Next: innodb-implicit-commit, Prev: innodb-next-key-locking, Up: innodb-transaction-model 14.6.8.6 Locks Set by Different SQL Statements in `InnoDB' .......................................................... A locking read, an *Note `UPDATE': update, or a *Note `DELETE': delete. generally set record locks on every index record that is scanned in the processing of the SQL statement. It does not matter whether there are `WHERE' conditions in the statement that would exclude the row. `InnoDB' does not remember the exact `WHERE' condition, but only knows which index ranges were scanned. The locks are normally next-key locks that also block inserts into the `gap' immediately before the record. However, gap locking can be disabled explicitly, which causes next-key locking not to be used. For more information, see *Note innodb-record-level-locks::. The transaction isolation level also can affect which locks are set; see *Note set-transaction::. If a secondary index is used in a search and index record locks to be set are exclusive, `InnoDB' also retrieves the corresponding clustered index records and sets locks on them. Differences between shared and exclusive locks are described in *Note innodb-lock-modes::. If you have no indexes suitable for your statement and MySQL must scan the entire table to process the statement, every row of the table becomes locked, which in turn blocks all inserts by other users to the table. It is important to create good indexes so that your queries do not unnecessarily scan many rows. For *Note `SELECT ... FOR UPDATE': select. or *Note `SELECT ... LOCK IN SHARE MODE': select, locks are acquired for scanned rows, and expected to be released for rows that do not qualify for inclusion in the result set (for example, if they do not meet the criteria given in the `WHERE' clause). However, in some cases, rows might not be unlocked immediately because the relationship between a result row and its original source is lost during query execution. For example, in a *Note `UNION': union, scanned (and locked) rows from a table might be inserted into a temporary table before evaluation whether they qualify for the result set. In this circumstance, the relationship of the rows in the temporary table to the rows in the original table is lost and the latter rows are not unlocked until the end of query execution. `InnoDB' sets specific types of locks as follows. * *Note `SELECT ... FROM': select. is a consistent read, reading a snapshot of the database and setting no locks unless the transaction isolation level is set to `SERIALIZABLE'. For `SERIALIZABLE' level, the search sets shared next-key locks on the index records it encounters. * *Note `SELECT ... FROM ... LOCK IN SHARE MODE': select. sets shared next-key locks on all index records the search encounters. * For index records the search encounters, *Note `SELECT ... FROM ... FOR UPDATE': select. blocks other sessions from doing *Note `SELECT ... FROM ... LOCK IN SHARE MODE': select. or from reading in certain transaction isolation levels. Consistent reads will ignore any locks set on the records that exist in the read view. * *Note `UPDATE ... WHERE ...': update. sets an exclusive next-key lock on every record the search encounters. * *Note `DELETE FROM ... WHERE ...': delete. sets an exclusive next-key lock on every record the search encounters. * *Note `INSERT': insert. sets an exclusive lock on the inserted row. This lock is an index-record lock, not a next-key lock (that is, there is no gap lock) and does not prevent other sessions from inserting into the gap before the inserted row. Prior to inserting the row, a type of gap lock called an insertion intention gap lock is set. This lock signals the intent to insert in such a way that multiple transactions inserting into the same index gap need not wait for each other if they are not inserting at the same position within the gap. Suppose that there are index records with values of 4 and 7. Separate transactions that attempt to insert values of 5 and 6 each lock the gap between 4 and 7 with insert intention locks prior to obtaining the exclusive lock on the inserted row, but do not block each other because the rows are nonconflicting. If a duplicate-key error occurs, a shared lock on the duplicate index record is set. This use of a shared lock can result in deadlock should there be multiple sessions trying to insert the same row if another session already has an exclusive lock. This can occur if another session deletes the row. Suppose that an `InnoDB' table `t1' has the following structure: CREATE TABLE t1 (i INT, PRIMARY KEY (i)) ENGINE = InnoDB; Now suppose that three sessions perform the following operations in order: Session 1: START TRANSACTION; INSERT INTO t1 VALUES(1); Session 2: START TRANSACTION; INSERT INTO t1 VALUES(1); Session 3: START TRANSACTION; INSERT INTO t1 VALUES(1); Session 1: ROLLBACK; The first operation by session 1 acquires an exclusive lock for the row. The operations by sessions 2 and 3 both result in a duplicate-key error and they both request a shared lock for the row. When session 1 rolls back, it releases its exclusive lock on the row and the queued shared lock requests for sessions 2 and 3 are granted. At this point, sessions 2 and 3 deadlock: Neither can acquire an exclusive lock for the row because of the shared lock held by the other. A similar situation occurs if the table already contains a row with key value 1 and three sessions perform the following operations in order: Session 1: START TRANSACTION; DELETE FROM t1 WHERE i = 1; Session 2: START TRANSACTION; INSERT INTO t1 VALUES(1); Session 3: START TRANSACTION; INSERT INTO t1 VALUES(1); Session 1: COMMIT; The first operation by session 1 acquires an exclusive lock for the row. The operations by sessions 2 and 3 both result in a duplicate-key error and they both request a shared lock for the row. When session 1 commits, it releases its exclusive lock on the row and the queued shared lock requests for sessions 2 and 3 are granted. At this point, sessions 2 and 3 deadlock: Neither can acquire an exclusive lock for the row because of the shared lock held by the other. * *Note `INSERT ... ON DUPLICATE KEY UPDATE': insert-on-duplicate. differs from a simple *Note `INSERT': insert. in that an exclusive next-key lock rather than a shared lock is placed on the row to be updated when a duplicate-key error occurs. * *Note `REPLACE': replace. is done like an *Note `INSERT': insert. if there is no collision on a unique key. Otherwise, an exclusive next-key lock is placed on the row to be replaced. * `INSERT INTO T SELECT ... FROM S WHERE ...' sets an exclusive index record without a gap lock on each row inserted into `T'. If the transaction isolation level is `READ COMMITTED' or `innodb_locks_unsafe_for_binlog' is enabled, and the transaction isolation level is not `SERIALIZABLE', `InnoDB' does the search on `S' as a consistent read (no locks). Otherwise, `InnoDB' sets shared next-key locks on rows from `S'. `InnoDB' has to set locks in the latter case: In roll-forward recovery from a backup, every SQL statement must be executed in exactly the same way it was done originally. *Note `CREATE TABLE ... SELECT ...': create-table. performs the *Note `SELECT': select. with shared next-key locks or as a consistent read, as for *Note `INSERT ... SELECT': insert-select. For `REPLACE INTO T SELECT ... FROM S WHERE ...', `InnoDB' sets shared next-key locks on rows from `S'. * While initializing a previously specified `AUTO_INCREMENT' column on a table, `InnoDB' sets an exclusive lock on the end of the index associated with the `AUTO_INCREMENT' column. In accessing the auto-increment counter, `InnoDB' uses a specific `AUTO-INC' table lock mode where the lock lasts only to the end of the current SQL statement, not to the end of the entire transaction. Other sessions cannot insert into the table while the `AUTO-INC' table lock is held; see *Note innodb-transaction-model::. `InnoDB' fetches the value of a previously initialized `AUTO_INCREMENT' column without setting any locks. * If a `FOREIGN KEY' constraint is defined on a table, any insert, update, or delete that requires the constraint condition to be checked sets shared record-level locks on the records that it looks at to check the constraint. `InnoDB' also sets these locks in the case where the constraint fails. * *Note `LOCK TABLES': lock-tables. sets table locks, but it is the higher MySQL layer above the `InnoDB' layer that sets these locks. `InnoDB' is aware of table locks if `innodb_table_locks = 1' (the default) and `autocommit = 0', and the MySQL layer above `InnoDB' knows about row-level locks. Otherwise, `InnoDB''s automatic deadlock detection cannot detect deadlocks where such table locks are involved. Also, because in this case the higher MySQL layer does not know about row-level locks, it is possible to get a table lock on a table where another session currently has row-level locks. However, this does not endanger transaction integrity, as discussed in *Note innodb-deadlock-detection::. See also *Note innodb-restrictions::.  File: manual.info, Node: innodb-implicit-commit, Next: innodb-deadlock-detection, Prev: innodb-locks-set, Up: innodb-transaction-model 14.6.8.7 Implicit Transaction Commit and Rollback ................................................. By default, MySQL starts the session for each new connection with autocommit mode enabled, so MySQL does a commit after each SQL statement if that statement did not return an error. If a statement returns an error, the commit or rollback behavior depends on the error. See *Note innodb-error-handling::. If a session that has autocommit disabled ends without explicitly committing the final transaction, MySQL rolls back that transaction. Some statements implicitly end a transaction, as if you had done a *Note `COMMIT': commit. before executing the statement. For details, see *Note implicit-commit::.  File: manual.info, Node: innodb-deadlock-detection, Next: innodb-deadlocks, Prev: innodb-implicit-commit, Up: innodb-transaction-model 14.6.8.8 Deadlock Detection and Rollback ........................................ `InnoDB' automatically detects transaction deadlocks and rolls back a transaction or transactions to break the deadlock. `InnoDB' tries to pick small transactions to roll back, where the size of a transaction is determined by the number of rows inserted, updated, or deleted. `InnoDB' is aware of table locks if `innodb_table_locks = 1' (the default) and `autocommit = 0', and the MySQL layer above it knows about row-level locks. Otherwise, `InnoDB' cannot detect deadlocks where a table lock set by a MySQL *Note `LOCK TABLES': lock-tables. statement or a lock set by a storage engine other than `InnoDB' is involved. Resolve these situations by setting the value of the `innodb_lock_wait_timeout' system variable. When `InnoDB' performs a complete rollback of a transaction, all locks set by the transaction are released. However, if just a single SQL statement is rolled back as a result of an error, some of the locks set by the statement may be preserved. This happens because `InnoDB' stores row locks in a format such that it cannot know afterward which lock was set by which statement. As of MySQL 5.1.24, if a *Note `SELECT': select. calls a stored function in a transaction, and a statement within the function fails, that statement rolls back. Furthermore, if *Note `ROLLBACK': commit. is executed after that, the entire transaction rolls back. Before 5.1.24, the failed statement did not roll back when it failed (even though it might ultimately get rolled back by a *Note `ROLLBACK': commit. later that rolls back the entire transaction).  File: manual.info, Node: innodb-deadlocks, Prev: innodb-deadlock-detection, Up: innodb-transaction-model 14.6.8.9 How to Cope with Deadlocks ................................... Deadlocks are a classic problem in transactional databases, but they are not dangerous unless they are so frequent that you cannot run certain transactions at all. Normally, you must write your applications so that they are always prepared to re-issue a transaction if it gets rolled back because of a deadlock. `InnoDB' uses automatic row-level locking. You can get deadlocks even in the case of transactions that just insert or delete a single row. That is because these operations are not really `atomic'; they automatically set locks on the (possibly several) index records of the row inserted or deleted. You can cope with deadlocks and reduce the likelihood of their occurrence with the following techniques: * Use *Note `SHOW ENGINE INNODB STATUS': show-engine. to determine the cause of the latest deadlock. That can help you to tune your application to avoid deadlocks. * Always be prepared to re-issue a transaction if it fails due to deadlock. Deadlocks are not dangerous. Just try again. * Commit your transactions often. Small transactions are less prone to collision. * If you are using locking reads (*Note `SELECT ... FOR UPDATE': select. or `SELECT ... LOCK IN SHARE MODE'), try using a lower isolation level such as `READ COMMITTED'. * Access your tables and rows in a fixed order. Then transactions form well-defined queues and do not deadlock. * Add well-chosen indexes to your tables. Then your queries need to scan fewer index records and consequently set fewer locks. Use *Note `EXPLAIN SELECT': explain. to determine which indexes the MySQL server regards as the most appropriate for your queries. * Use less locking. If you can afford to permit a *Note `SELECT': select. to return data from an old snapshot, do not add the clause `FOR UPDATE' or `LOCK IN SHARE MODE' to it. Using the `READ COMMITTED' isolation level is good here, because each consistent read within the same transaction reads from its own fresh snapshot. * If nothing else helps, serialize your transactions with table-level locks. The correct way to use *Note `LOCK TABLES': lock-tables. with transactional tables, such as `InnoDB' tables, is to begin a transaction with `SET autocommit = 0' (not *Note `START TRANSACTION': commit.) followed by *Note `LOCK TABLES': lock-tables, and to not call *Note `UNLOCK TABLES': lock-tables. until you commit the transaction explicitly. For example, if you need to write to table `t1' and read from table `t2', you can do this: SET autocommit=0; LOCK TABLES t1 WRITE, t2 READ, ...; ... DO SOMETHING WITH TABLES T1 AND T2 HERE ... COMMIT; UNLOCK TABLES; Table-level locks make your transactions queue nicely and avoid deadlocks. * Another way to serialize transactions is to create an auxiliary `semaphore' table that contains just a single row. Have each transaction update that row before accessing other tables. In that way, all transactions happen in a serial fashion. Note that the `InnoDB' instant deadlock detection algorithm also works in this case, because the serializing lock is a row-level lock. With MySQL table-level locks, the timeout method must be used to resolve deadlocks.  File: manual.info, Node: innodb-multi-versioning, Next: innodb-table-and-index, Prev: innodb-transaction-model, Up: innodb-storage-engine 14.6.9 `InnoDB' Multi-Versioning -------------------------------- `InnoDB' is a multi-versioned storage engine: it keeps information about old versions of changed rows, to support transactional features such as concurrency and rollback. This information is stored in the tablespace in a data structure called a rollback segment (http://dev.mysql.com/doc/innodb-plugin/1.0/en/glossary.html#glos_rollback_segment) (after an analogous data structure in Oracle). `InnoDB' uses the information in the rollback segment to perform the undo operations needed in a transaction rollback. It also uses the information to build earlier versions of a row for a consistent read. * Internal Details of Multi-Versioning * Internally, `InnoDB' adds three fields to each row stored in the database. A 6-byte `DB_TRX_ID' field indicates the transaction identifier for the last transaction that inserted or updated the row. Also, a deletion is treated internally as an update where a special bit in the row is set to mark it as deleted. Each row also contains a 7-byte `DB_ROLL_PTR' field called the roll pointer. The roll pointer points to an undo log record written to the rollback segment. If the row was updated, the undo log record contains the information necessary to rebuild the content of the row before it was updated. A 6-byte `DB_ROW_ID' field contains a row ID that increases monotonically as new rows are inserted. If `InnoDB' generates a clustered index automatically, the index contains row ID values. Otherwise, the `DB_ROW_ID' column does not appear in any index. Undo logs in the rollback segment are divided into insert and update undo logs. Insert undo logs are needed only in transaction rollback and can be discarded as soon as the transaction commits. Update undo logs are used also in consistent reads, but they can be discarded only after there is no transaction present for which `InnoDB' has assigned a snapshot that in a consistent read could need the information in the update undo log to build an earlier version of a database row. * Guidelines for Managing Rollback Segments * Commit your transactions regularly, including those transactions that issue only consistent reads. Otherwise, `InnoDB' cannot discard data from the update undo logs, and the rollback segment may grow too big, filling up your tablespace. The physical size of an undo log record in the rollback segment is typically smaller than the corresponding inserted or updated row. You can use this information to calculate the space needed for your rollback segment. In the `InnoDB' multi-versioning scheme, a row is not physically removed from the database immediately when you delete it with an SQL statement. `InnoDB' only physically removes the corresponding row and its index records when it discards the update undo log record written for the deletion. This removal operation is called a purge (http://dev.mysql.com/doc/innodb-plugin/1.0/en/glossary.html#glos_purge), and it is quite fast, usually taking the same order of time as the SQL statement that did the deletion. If you insert and delete rows in smallish batches at about the same rate in the table, the purge thread can start to lag behind and the table can grow bigger and bigger because of all the `dead' rows, making everything disk-bound and very slow In such a case, throttle new row operations, and allocate more resources to the purge thread by tuning the `innodb_max_purge_lag' system variable. See *Note innodb-parameters:: for more information.  File: manual.info, Node: innodb-table-and-index, Next: innodb-disk-management, Prev: innodb-multi-versioning, Up: innodb-storage-engine 14.6.10 `InnoDB' Table and Index Structures ------------------------------------------- * Menu: * innodb-index-types:: Clustered and Secondary Indexes * innodb-physical-structure:: Physical Structure of an Index * innodb-insert-buffering:: Insert Buffering * innodb-adaptive-hash:: Adaptive Hash Indexes * innodb-physical-record:: Physical Row Structure MySQL stores its data dictionary information for tables in `.frm' files in database directories. This is true for all MySQL storage engines, but every `InnoDB' table also has its own entry in the `InnoDB' internal data dictionary inside the tablespace. When MySQL drops a table or a database, it has to delete one or more `.frm' files as well as the corresponding entries inside the `InnoDB' data dictionary. Consequently, you cannot move `InnoDB' tables between databases simply by moving the `.frm' files.  File: manual.info, Node: innodb-index-types, Next: innodb-physical-structure, Prev: innodb-table-and-index, Up: innodb-table-and-index 14.6.10.1 Clustered and Secondary Indexes ......................................... Every `InnoDB' table has a special index called the _clustered index_ where the data for the rows is stored: * If you define a `PRIMARY KEY' on your table, `InnoDB' uses it as the clustered index. * If you do not define a `PRIMARY KEY' for your table, MySQL picks the first `UNIQUE' index that has only `NOT NULL' columns as the primary key and `InnoDB' uses it as the clustered index. * If the table has no `PRIMARY KEY' or suitable `UNIQUE' index, `InnoDB' internally generates a hidden clustered index on a synthetic column containing row ID values. The rows are ordered by the ID that `InnoDB' assigns to the rows in such a table. The row ID is a 6-byte field that increases monotonically as new rows are inserted. Thus, the rows ordered by the row ID are physically in insertion order. Accessing a row through the clustered index is fast because the row data is on the same page where the index search leads. If a table is large, the clustered index architecture often saves a disk I/O operation when compared to storage organizations that store row data using a different page from the index record. (For example, `MyISAM' uses one file for data rows and another for index records.) In `InnoDB', the records in nonclustered indexes (also called secondary indexes) contain the primary key columns for the row that are not in the secondary index. `InnoDB' uses this primary key value to search for the row in the clustered index. If the primary key is long, the secondary indexes use more space, so it is advantageous to have a short primary key.  File: manual.info, Node: innodb-physical-structure, Next: innodb-insert-buffering, Prev: innodb-index-types, Up: innodb-table-and-index 14.6.10.2 Physical Structure of an Index ........................................ All `InnoDB' indexes are B-trees where the index records are stored in the leaf pages of the tree. The default size of an index page is 16KB. When new records are inserted, `InnoDB' tries to leave 1/16 of the page free for future insertions and updates of the index records. If index records are inserted in a sequential order (ascending or descending), the resulting index pages are about 15/16 full. If records are inserted in a random order, the pages are from 1/2 to 15/16 full. If the fill factor of an index page drops below 1/2, `InnoDB' tries to contract the index tree to free the page. *Note*: Changing the page size is not a supported operation and there is no guarantee that *Note `InnoDB': innodb-storage-engine. will function normally with a page size other than 16KB. Problems compiling or running InnoDB may occur. In particular, `ROW_FORMAT=COMPRESSED' in the `InnoDB Plugin' assumes that the page size is at most 16KB and uses 14-bit pointers. A version of *Note `InnoDB': innodb-storage-engine. built for one page size cannot use data files or log files from a version built for a different page size.  File: manual.info, Node: innodb-insert-buffering, Next: innodb-adaptive-hash, Prev: innodb-physical-structure, Up: innodb-table-and-index 14.6.10.3 Insert Buffering .......................... It is a common situation in database applications that the primary key is a unique identifier and new rows are inserted in the ascending order of the primary key. Thus, insertions into the clustered index do not require random reads from a disk. On the other hand, secondary indexes are usually nonunique, and insertions into secondary indexes happen in a relatively random order. This would cause a lot of random disk I/O operations without a special mechanism used in `InnoDB'. If an index record should be inserted into a nonunique secondary index, `InnoDB' checks whether the secondary index page is in the buffer pool. If that is the case, `InnoDB' does the insertion directly to the index page. If the index page is not found in the buffer pool, `InnoDB' inserts the record to a special insert buffer structure. The insert buffer is kept so small that it fits entirely in the buffer pool, and insertions can be done very fast. Periodically, the insert buffer is merged into the secondary index trees in the database. Often it is possible to merge several insertions into the same page of the index tree, saving disk I/O operations. It has been measured that the insert buffer can speed up insertions into a table up to 15 times. The insert buffer merging may continue to happen _after_ the inserting transaction has been committed. In fact, it may continue to happen after a server shutdown and restart (see *Note forcing-innodb-recovery::). Insert buffer merging may take many hours when many secondary indexes must be updated and many rows have been inserted. During this time, disk I/O will be increased, which can cause significant slowdown on disk-bound queries. Another significant background I/O operation is the purge thread (see *Note innodb-multi-versioning::).  File: manual.info, Node: innodb-adaptive-hash, Next: innodb-physical-record, Prev: innodb-insert-buffering, Up: innodb-table-and-index 14.6.10.4 Adaptive Hash Indexes ............................... If a table fits almost entirely in main memory, the fastest way to perform queries on it is to use hash indexes. `InnoDB' has a mechanism that monitors index searches made to the indexes defined for a table. If `InnoDB' notices that queries could benefit from building a hash index, it does so automatically. The hash index is always built based on an existing B-tree index on the table. `InnoDB' can build a hash index on a prefix of any length of the key defined for the B-tree, depending on the pattern of searches that `InnoDB' observes for the B-tree index. A hash index can be partial: It is not required that the whole B-tree index is cached in the buffer pool. `InnoDB' builds hash indexes on demand for those pages of the index that are often accessed. In a sense, `InnoDB' tailors itself through the adaptive hash index mechanism to ample main memory, coming closer to the architecture of main-memory databases.  File: manual.info, Node: innodb-physical-record, Prev: innodb-adaptive-hash, Up: innodb-table-and-index 14.6.10.5 Physical Row Structure ................................ The physical row structure for an `InnoDB' table depends on the row format specified when the table was created. For MySQL 5.1, `InnoDB' uses the `COMPACT' format by default, but the `REDUNDANT' format is available to retain compatibility with older versions of MySQL. To check the row format of an `InnoDB' table, use *Note `SHOW TABLE STATUS': show-table-status. The compact row format decreases row storage space by about 20% at the cost of increasing CPU use for some operations. If your workload is a typical one that is limited by cache hit rates and disk speed, compact format is likely to be faster. If the workload is a rare case that is limited by CPU speed, compact format might be slower. Rows in `InnoDB' tables that use `REDUNDANT' row format have the following characteristics: * Each index record contains a six-byte header. The header is used to link together consecutive records, and also in row-level locking. * Records in the clustered index contain fields for all user-defined columns. In addition, there is a six-byte transaction ID field and a seven-byte roll pointer field. * If no primary key was defined for a table, each clustered index record also contains a six-byte row ID field. * Each secondary index record also contains all the primary key fields defined for the clustered index key that are not in the secondary index. * A record contains a pointer to each field of the record. If the total length of the fields in a record is less than 128 bytes, the pointer is one byte; otherwise, two bytes. The array of these pointers is called the record directory. The area where these pointers point is called the data part of the record. * Internally, `InnoDB' stores fixed-length character columns such as *Note `CHAR(10)': char. in a fixed-length format. `InnoDB' does not truncate trailing spaces from *Note `VARCHAR': char. columns. * An SQL `NULL' value reserves one or two bytes in the record directory. Besides that, an SQL `NULL' value reserves zero bytes in the data part of the record if stored in a variable length column. In a fixed-length column, it reserves the fixed length of the column in the data part of the record. Reserving the fixed space for `NULL' values enables an update of the column from `NULL' to a non-`NULL' value to be done in place without causing fragmentation of the index page. Rows in `InnoDB' tables that use `COMPACT' row format have the following characteristics: * Each index record contains a five-byte header that may be preceded by a variable-length header. The header is used to link together consecutive records, and also in row-level locking. * The variable-length part of the record header contains a bit vector for indicating `NULL' columns. If the number of columns in the index that can be `NULL' is N, the bit vector occupies `CEILING(N/8)' bytes. (For example, if there are anywhere from 9 to 15 columns that can be `NULL', the bit vector uses two bytes.) Columns that are `NULL' do not occupy space other than the bit in this vector. The variable-length part of the header also contains the lengths of variable-length columns. Each length takes one or two bytes, depending on the maximum length of the column. If all columns in the index are `NOT NULL' and have a fixed length, the record header has no variable-length part. * For each non-`NULL' variable-length field, the record header contains the length of the column in one or two bytes. Two bytes will only be needed if part of the column is stored externally in overflow pages or the maximum length exceeds 255 bytes and the actual length exceeds 127 bytes. For an externally stored column, the two-byte length indicates the length of the internally stored part plus the 20-byte pointer to the externally stored part. The internal part is 768 bytes, so the length is 768+20. The 20-byte pointer stores the true length of the column. * The record header is followed by the data contents of the non-`NULL' columns. * Records in the clustered index contain fields for all user-defined columns. In addition, there is a six-byte transaction ID field and a seven-byte roll pointer field. * If no primary key was defined for a table, each clustered index record also contains a six-byte row ID field. * Each secondary index record also contains all the primary key fields defined for the clustered index key that are not in the secondary index. If any of these primary key fields are variable length, the record header for each secondary index will have a variable-length part to record their lengths, even if the secondary index is defined on fixed-length columns. * Internally, `InnoDB' stores fixed-length, fixed-width character columns such as *Note `CHAR(10)': char. in a fixed-length format. `InnoDB' does not truncate trailing spaces from *Note `VARCHAR': char. columns. * Internally, `InnoDB' attempts to store UTF-8 *Note `CHAR(N)': char. columns in N bytes by trimming trailing spaces. (With `REDUNDANT' row format, such columns occupy 3 x N bytes.) Reserving the minimum space N in many cases enables column updates to be done in place without causing fragmentation of the index page.  File: manual.info, Node: innodb-disk-management, Next: innodb-error-handling, Prev: innodb-table-and-index, Up: innodb-storage-engine 14.6.11 `InnoDB' Disk I/O and File Space Management --------------------------------------------------- * Menu: * innodb-disk-io:: `InnoDB' Disk I/O * innodb-file-space:: File Space Management * innodb-file-defragmenting:: Defragmenting a Table  File: manual.info, Node: innodb-disk-io, Next: innodb-file-space, Prev: innodb-disk-management, Up: innodb-disk-management 14.6.11.1 `InnoDB' Disk I/O ........................... `InnoDB' uses simulated asynchronous disk I/O: `InnoDB' creates a number of threads to take care of I/O operations, such as read-ahead. There are two read-ahead heuristics in `InnoDB': * In sequential read-ahead, if `InnoDB' notices that the access pattern to a segment in the tablespace is sequential, it posts in advance a batch of reads of database pages to the I/O system. * In random read-ahead, if `InnoDB' notices that some area in a tablespace seems to be in the process of being fully read into the buffer pool, it posts the remaining reads to the I/O system. `InnoDB' uses a novel file flush technique called _doublewrite_. It adds safety to recovery following an operating system crash or a power outage, and improves performance on most varieties of Unix by reducing the need for `fsync()' operations. Doublewrite means that before writing pages to a data file, `InnoDB' first writes them to a contiguous tablespace area called the doublewrite buffer. Only after the write and the flush to the doublewrite buffer has completed does `InnoDB' write the pages to their proper positions in the data file. If the operating system crashes in the middle of a page write, `InnoDB' can later find a good copy of the page from the doublewrite buffer during recovery.  File: manual.info, Node: innodb-file-space, Next: innodb-file-defragmenting, Prev: innodb-disk-io, Up: innodb-disk-management 14.6.11.2 File Space Management ............................... The data files that you define in the configuration file form the `InnoDB' tablespace. The files are logically concatenated to form the tablespace. There is no striping in use. Currently, you cannot define where within the tablespace your tables are allocated. However, in a newly created tablespace, `InnoDB' allocates space starting from the first data file. The tablespace consists of database pages with a default size of 16KB. The pages are grouped into extents of size 1MB (64 consecutive pages). The `files' inside a tablespace are called _segments_ in `InnoDB'. The term `rollback segment' is somewhat confusing because it actually contains many tablespace segments. When a segment grows inside the tablespace, `InnoDB' allocates the first 32 pages to it individually. After that, `InnoDB' starts to allocate whole extents to the segment. `InnoDB' can add up to 4 extents at a time to a large segment to ensure good sequentiality of data. Two segments are allocated for each index in `InnoDB'. One is for nonleaf nodes of the B-tree, the other is for the leaf nodes. The idea here is to achieve better sequentiality for the leaf nodes, which contain the data. Some pages in the tablespace contain bitmaps of other pages, and therefore a few extents in an `InnoDB' tablespace cannot be allocated to segments as a whole, but only as individual pages. When you ask for available free space in the tablespace by issuing a *Note `SHOW TABLE STATUS': show-table-status. statement, `InnoDB' reports the extents that are definitely free in the tablespace. `InnoDB' always reserves some extents for cleanup and other internal purposes; these reserved extents are not included in the free space. When you delete data from a table, `InnoDB' contracts the corresponding B-tree indexes. Whether the freed space becomes available for other users depends on whether the pattern of deletes frees individual pages or extents to the tablespace. Dropping a table or deleting all rows from it is guaranteed to release the space to other users, but remember that deleted rows are physically removed only in an (automatic) purge operation after they are no longer needed for transaction rollbacks or consistent reads. (See *Note innodb-multi-versioning::.) To see information about the tablespace, use the Tablespace Monitor. See *Note innodb-monitors::. The maximum row length, except for variable-length columns (*Note `VARBINARY': binary-varbinary, *Note `VARCHAR': char, *Note `BLOB': blob. and *Note `TEXT': blob.), is slightly less than half of a database page. That is, the maximum row length is about 8000 bytes. *Note `LONGBLOB': blob. and *Note `LONGTEXT': blob. columns must be less than 4GB, and the total row length, including *Note `BLOB': blob. and *Note `TEXT': blob. columns, must be less than 4GB. If a row is less than half a page long, all of it is stored locally within the page. If it exceeds half a page, variable-length columns are chosen for external off-page storage until the row fits within half a page. For a column chosen for off-page storage, `InnoDB' stores the first 768 bytes locally in the row, and the rest externally into overflow pages. Each such column has its own list of overflow pages. The 768-byte prefix is accompanied by a 20-byte value that stores the true length of the column and points into the overflow list where the rest of the value is stored.  File: manual.info, Node: innodb-file-defragmenting, Prev: innodb-file-space, Up: innodb-disk-management 14.6.11.3 Defragmenting a Table ............................... If there are random insertions into or deletions from the indexes of a table, the indexes may become fragmented. Fragmentation means that the physical ordering of the index pages on the disk is not close to the index ordering of the records on the pages, or that there are many unused pages in the 64-page blocks that were allocated to the index. One symptom of fragmentation is that a table takes more space than it `should' take. How much that is exactly, is difficult to determine. All `InnoDB' data and indexes are stored in B-trees, and their fill factor may vary from 50% to 100%. Another symptom of fragmentation is that a table scan such as this takes more time than it `should' take: SELECT COUNT(*) FROM t WHERE a_non_indexed_column <> 12345; (In the preceding query, we are `fooling' the SQL optimizer into scanning the clustered index rather than a secondary index.) Most disks can read 10MB/s to 50MB/s, which can be used to estimate how fast a table scan should be. It can speed up index scans if you periodically perform a `null' *Note `ALTER TABLE': alter-table. operation, which causes MySQL to rebuild the table: ALTER TABLE TBL_NAME ENGINE=INNODB Another way to perform a defragmentation operation is to use *Note `mysqldump': mysqldump. to dump the table to a text file, drop the table, and reload it from the dump file. If the insertions into an index are always ascending and records are deleted only from the end, the `InnoDB' filespace management algorithm guarantees that fragmentation in the index does not occur.  File: manual.info, Node: innodb-error-handling, Next: innodb-tuning-troubleshooting, Prev: innodb-disk-management, Up: innodb-storage-engine 14.6.12 `InnoDB' Error Handling ------------------------------- * Menu: * innodb-error-codes:: `InnoDB' Error Codes * operating-system-error-codes:: Operating System Error Codes Error handling in `InnoDB' is not always the same as specified in the SQL standard. According to the standard, any error during an SQL statement should cause rollback of that statement. `InnoDB' sometimes rolls back only part of the statement, or the whole transaction. The following items describe how `InnoDB' performs error handling: * If you run out of file space in the tablespace, a MySQL `Table is full' error occurs and `InnoDB' rolls back the SQL statement. * A transaction deadlock causes `InnoDB' to roll back the entire transaction. Retry the whole transaction when this happens. A lock wait timeout causes `InnoDB' to roll back only the single statement that was waiting for the lock and encountered the timeout. (To have the entire transaction roll back, start the server with the `--innodb_rollback_on_timeout' option, available as of MySQL 5.1.15.) Retry the statement if using the current behavior, or the entire transaction if using `--innodb_rollback_on_timeout'. Both deadlocks and lock wait timeouts are normal on busy servers and it is necessary for applications to be aware that they may happen and handle them by retrying. You can make them less likely by doing as little work as possible between the first change to data during a transaction and the commit, so the locks are held for the shortest possible time and for the smallest possible number of rows. Sometimes splitting work between different transactions may be practical and helpful. When a transaction rollback occurs due to a deadlock or lock wait timeout, it cancels the effect of the statements within the transaction. But if the start-transaction statement was *Note `START TRANSACTION': commit. or *Note `BEGIN': commit. statement, rollback does not cancel that statement. Further SQL statements become part of the transaction until the occurrence of *Note `COMMIT': commit, *Note `ROLLBACK': commit, or some SQL statement that causes an implicit commit. * A duplicate-key error rolls back the SQL statement, if you have not specified the `IGNORE' option in your statement. * A `row too long error' rolls back the SQL statement. * Other errors are mostly detected by the MySQL layer of code (above the `InnoDB' storage engine level), and they roll back the corresponding SQL statement. Locks are not released in a rollback of a single SQL statement. During implicit rollbacks, as well as during the execution of an explicit *Note `ROLLBACK': commit. SQL statement, *Note `SHOW PROCESSLIST': show-processlist. displays `Rolling back' in the `State' column for the relevant connection.  File: manual.info, Node: innodb-error-codes, Next: operating-system-error-codes, Prev: innodb-error-handling, Up: innodb-error-handling 14.6.12.1 `InnoDB' Error Codes .............................. The following is a nonexhaustive list of common `InnoDB'-specific errors that you may encounter, with information about why each occurs and how to resolve the problem. * `1005 (ER_CANT_CREATE_TABLE)' Cannot create table. If the error message refers to error 150, table creation failed because a foreign key constraint was not correctly formed. If the error message refers to error -1, table creation probably failed because the table includes a column name that matched the name of an internal `InnoDB' table. * `1016 (ER_CANT_OPEN_FILE)' Cannot find the `InnoDB' table from the `InnoDB' data files, although the `.frm' file for the table exists. See *Note innodb-troubleshooting-datadict::. * `1114 (ER_RECORD_FILE_FULL)' `InnoDB' has run out of free space in the tablespace. Reconfigure the tablespace to add a new data file. * `1205 (ER_LOCK_WAIT_TIMEOUT)' Lock wait timeout expired. Transaction was rolled back. * `1206 (ER_LOCK_TABLE_FULL)' The total number of locks exceeds the lock table size. To avoid this error, increase the value of `innodb_buffer_pool_size'. Within an individual application, a workaround may be to break a large operation into smaller pieces. For example, if the error occurs for a large *Note `INSERT': insert, perform several smaller *Note `INSERT': insert. operations. * `1213 (ER_LOCK_DEADLOCK)' Transaction deadlock. Rerun the transaction. * `1216 (ER_NO_REFERENCED_ROW)' You are trying to add a row but there is no parent row, and a foreign key constraint fails. Add the parent row first. * `1217 (ER_ROW_IS_REFERENCED)' You are trying to delete a parent row that has children, and a foreign key constraint fails. Delete the children first.  File: manual.info, Node: operating-system-error-codes, Prev: innodb-error-codes, Up: innodb-error-handling 14.6.12.2 Operating System Error Codes ...................................... To print the meaning of an operating system error number, use the *Note `perror': perror. program that comes with the MySQL distribution. * *Linux System Error Codes* The following table provides a list of some common Linux system error codes. For a more complete list, see Linux source code (http://www.finalcog.com/c-error-codes-include-errno). Number Macro Description 1 `EPERM' Operation not permitted 2 `ENOENT' No such file or directory 3 `ESRCH' No such process 4 `EINTR' Interrupted system call 5 `EIO' I/O error 6 `ENXIO' No such device or address 7 `E2BIG' Arg list too long 8 `ENOEXEC' Exec format error 9 `EBADF' Bad file number 10 `ECHILD' No child processes 11 `EAGAIN' Try again 12 `ENOMEM' Out of memory 13 `EACCES' Permission denied 14 `EFAULT' Bad address 15 `ENOTBLK' Block device required 16 `EBUSY' Device or resource busy 17 `EEXIST' File exists 18 `EXDEV' Cross-device link 19 `ENODEV' No such device 20 `ENOTDIR' Not a directory 21 `EISDIR' Is a directory 22 `EINVAL' Invalid argument 23 `ENFILE' File table overflow 24 `EMFILE' Too many open files 25 `ENOTTY' Inappropriate ioctl for device 26 `ETXTBSY' Text file busy 27 `EFBIG' File too large 28 `ENOSPC' No space left on device 29 `ESPIPE' Illegal seek 30 `EROFS' Read-only file system 31 `EMLINK' Too many links * *Windows System Error Codes* The following table provides a list of some common Windows system error codes. For a complete list, see the Microsoft Web site (http://msdn.microsoft.com/en-us/library/ms681381.aspx). Number Macro Description 1 `ERROR_INVALID_FUNCTION'Incorrect function. 2 `ERROR_FILE_NOT_FOUND'The system cannot find the file specified. 3 `ERROR_PATH_NOT_FOUND'The system cannot find the path specified. 4 `ERROR_TOO_MANY_OPEN_FILES'The system cannot open the file. 5 `ERROR_ACCESS_DENIED'Access is denied. 6 `ERROR_INVALID_HANDLE'The handle is invalid. 7 `ERROR_ARENA_TRASHED'The storage control blocks were destroyed. 8 `ERROR_NOT_ENOUGH_MEMORY'Not enough storage is available to process this command. 9 `ERROR_INVALID_BLOCK'The storage control block address is invalid. 10 `ERROR_BAD_ENVIRONMENT'The environment is incorrect. 11 `ERROR_BAD_FORMAT'An attempt was made to load a program with an incorrect format. 12 `ERROR_INVALID_ACCESS'The access code is invalid. 13 `ERROR_INVALID_DATA'The data is invalid. 14 `ERROR_OUTOFMEMORY'Not enough storage is available to complete this operation. 15 `ERROR_INVALID_DRIVE'The system cannot find the drive specified. 16 `ERROR_CURRENT_DIRECTORY'The directory cannot be removed. 17 `ERROR_NOT_SAME_DEVICE'The system cannot move the file to a different disk drive. 18 `ERROR_NO_MORE_FILES'There are no more files. 19 `ERROR_WRITE_PROTECT'The media is write protected. 20 `ERROR_BAD_UNIT'The system cannot find the device specified. 21 `ERROR_NOT_READY'The device is not ready. 22 `ERROR_BAD_COMMAND'The device does not recognize the command. 23 `ERROR_CRC' Data error (cyclic redundancy check). 24 `ERROR_BAD_LENGTH'The program issued a command but the command length is incorrect. 25 `ERROR_SEEK' The drive cannot locate a specific area or track on the disk. 26 `ERROR_NOT_DOS_DISK'The specified disk or diskette cannot be accessed. 27 `ERROR_SECTOR_NOT_FOUND'The drive cannot find the sector requested. 28 `ERROR_OUT_OF_PAPER'The printer is out of paper. 29 `ERROR_WRITE_FAULT'The system cannot write to the specified device. 30 `ERROR_READ_FAULT'The system cannot read from the specified device. 31 `ERROR_GEN_FAILURE'A device attached to the system is not functioning. 32 `ERROR_SHARING_VIOLATION'The process cannot access the file because it is being used by another process. 33 `ERROR_LOCK_VIOLATION'The process cannot access the file because another process has locked a portion of the file. 34 `ERROR_WRONG_DISK'The wrong diskette is in the drive. Insert %2 (Volume Serial Number: %3) into drive %1. 36 `ERROR_SHARING_BUFFER_EXCEEDED'Too many files opened for sharing. 38 `ERROR_HANDLE_EOF'Reached the end of the file. 39 `ERROR_HANDLE_DISK_FULL'The disk is full. 87 `ERROR_INVALID_PARAMETER'The parameter is incorrect. 112 `ERROR_DISK_FULL'The disk is full. 123 `ERROR_INVALID_NAME'The file name, directory name, or volume label syntax is incorrect. 1450 `ERROR_NO_SYSTEM_RESOURCES'Insufficient system resources exist to complete the requested service.  File: manual.info, Node: innodb-tuning-troubleshooting, Next: innodb-restrictions, Prev: innodb-error-handling, Up: innodb-storage-engine 14.6.13 `InnoDB' Performance Tuning and Troubleshooting ------------------------------------------------------- * Menu: * innodb-tuning:: `InnoDB' Performance Tuning Tips * innodb-monitors:: `SHOW ENGINE INNODB STATUS' and the `InnoDB' Monitors * innodb-troubleshooting:: `InnoDB' General Troubleshooting * innodb-troubleshooting-datadict:: Troubleshooting `InnoDB' Data Dictionary Operations  File: manual.info, Node: innodb-tuning, Next: innodb-monitors, Prev: innodb-tuning-troubleshooting, Up: innodb-tuning-troubleshooting 14.6.13.1 `InnoDB' Performance Tuning Tips .......................................... The followings tips are grouped by category. Some of them can apply in multiple categories, so it is useful to read them all. *Storage Layout Tips* * In `InnoDB', having a long `PRIMARY KEY' wastes a lot of disk space because its value must be stored with every secondary index record. (See *Note innodb-table-and-index::.) Create an `AUTO_INCREMENT' column as the primary key if your primary key is long. * Use the *Note `VARCHAR': char. data type instead of *Note `CHAR': char. if you are storing variable-length strings or if the column may contain many `NULL' values. A *Note `CHAR(N)': char. column always takes N characters to store data, even if the string is shorter or its value is `NULL'. Smaller tables fit better in the buffer pool and reduce disk I/O. When using `COMPACT' row format (the default `InnoDB' format in MySQL 5.1) and variable-length character sets, such as `utf8' or `sjis', *Note `CHAR(N)': char. will occupy a variable amount of space, at least N bytes. *Transaction Management Tips* * Wrap several modifications into a single transaction to reduce the number of flush operations. `InnoDB' must flush the log to disk at each transaction commit if that transaction made modifications to the database. The rotation speed of a disk is typically at most 167 revolutions/second (for a 10,000RPM disk), which constrains the number of commits to the same 167^th of a second if the disk does not `fool' the operating system. * If you can afford the loss of some of the latest committed transactions if a crash occurs, you can set the `innodb_flush_log_at_trx_commit' parameter to 0. `InnoDB' tries to flush the log once per second anyway, although the flush is not guaranteed. Also, set the value of `innodb_support_xa' to 0, which will reduce the number of disk flushes due to synchronizing on disk data and the binary log. *Disk I/O Tips* * `innodb_buffer_pool_size' specifies the size of the buffer pool. If your buffer pool is small and you have sufficient memory, making the pool larger can improve performance by reducing the amount of disk I/O needed as queries access *Note `InnoDB': innodb-storage-engine. tables. For more information about the pool, see *Note innodb-buffer-pool::. * Beware of big rollbacks of mass inserts: `InnoDB' uses the insert buffer to save disk I/O in inserts, but no such mechanism is used in a corresponding rollback. A disk-bound rollback can take 30 times as long to perform as the corresponding insert. Killing the database process does not help because the rollback starts again on server startup. The only way to get rid of a runaway rollback is to increase the buffer pool so that the rollback becomes CPU-bound and runs fast, or to use a special procedure. See *Note forcing-innodb-recovery::. * Beware also of other big disk-bound operations. Use *Note `DROP TABLE': drop-table. and *Note `CREATE TABLE': create-table. to empty a table, not `DELETE FROM TBL_NAME'. * In some versions of GNU/Linux and Unix, flushing files to disk with the Unix `fsync()' call (which `InnoDB' uses by default) and other similar methods is surprisingly slow. If you are dissatisfied with database write performance, you might try setting the `innodb_flush_method' parameter to `O_DSYNC'. The `O_DSYNC' flush method seems to perform slower on most systems, but yours might not be one of them. * When using the `InnoDB' storage engine on Solaris 10 for x86_64 architecture (AMD Opteron), it is important to use direct I/O for `InnoDB'-related files. Failure to do so may cause degradation of `InnoDB''s speed and performance on this platform. To use direct I/O for an entire UFS file system used for storing `InnoDB'-related files, mount it with the `forcedirectio' option; see `mount_ufs(1M)'. (The default on Solaris 10/x86_64 is _not_ to use this option.) Alternatively, as of MySQL 5.1.18 you can set `innodb_flush_method = O_DIRECT' if you do not want to affect the entire file system. This causes `InnoDB' to call `directio()' instead of `fcntl()'. However, setting `innodb_flush_method' to `O_DIRECT' causes `InnoDB' to use direct I/O only for data files, not the log files. When using the `InnoDB' storage engine with a large `innodb_buffer_pool_size' value on any release of Solaris 2.6 and up and any platform (sparc/x86/x64/amd64), a significant performance gain might be achieved by placing `InnoDB' data files and log files on raw devices or on a separate direct I/O UFS file system using the `forcedirectio' mount option as described earlier (it is necessary to use the mount option rather than setting `innodb_flush_method' if you want direct I/O for the log files). Users of the Veritas file system VxFS should use the `convosync=direct' mount option. You are advised to perform tests with and without raw partitions or direct I/O file systems to verify whether performance is improved on your system. Other MySQL data files, such as those for `MyISAM' tables, should not be placed on a direct I/O file system. Executables or libraries _must not_ be placed on a direct I/O file system. * If the Unix `top' tool or the Windows Task Manager shows that the CPU usage percentage with your workload is less than 70%, your workload is probably disk-bound. Maybe you are making too many transaction commits, or the buffer pool is too small. Making the buffer pool bigger can help, but do not set it equal to more than 80% of physical memory. *Logging Tips* * Make your log files big, even as big as the buffer pool. When `InnoDB' has written the log files full, it must write the modified contents of the buffer pool to disk in a checkpoint. Small log files cause many unnecessary disk writes. The disadvantage of big log files is that the recovery time is longer. * Make the log buffer quite large as well (on the order of 8MB). *Bulk Data Loading Tips* * When importing data into `InnoDB', make sure that MySQL does not have autocommit mode enabled because that requires a log flush to disk for every insert. To disable autocommit during your import operation, surround it with *Note `SET autocommit': commit. and *Note `COMMIT': commit. statements: SET autocommit=0; ... SQL IMPORT STATEMENTS ... COMMIT; If you use the *Note `mysqldump': mysqldump. option `--opt', you get dump files that are fast to import into an `InnoDB' table, even without wrapping them with the *Note `SET autocommit': commit. and *Note `COMMIT': commit. statements. * If you have `UNIQUE' constraints on secondary keys, you can speed up table imports by temporarily turning off the uniqueness checks during the import session: SET unique_checks=0; ... SQL IMPORT STATEMENTS ... SET unique_checks=1; For big tables, this saves a lot of disk I/O because `InnoDB' can use its insert buffer to write secondary index records in a batch. Be certain that the data contains no duplicate keys. * If you have `FOREIGN KEY' constraints in your tables, you can speed up table imports by turning the foreign key checks off for the duration of the import session: SET foreign_key_checks=0; ... SQL IMPORT STATEMENTS ... SET foreign_key_checks=1; For big tables, this can save a lot of disk I/O. *Other Tips* * Unlike `MyISAM', `InnoDB' does not store an index cardinality value in its tables. Instead, `InnoDB' computes a cardinality for a table the first time it accesses it after startup. With a large number of tables, this might take significant time. It is the initial table open operation that is important, so to `warm up' a table for later use, access it immediately after startup by issuing a statement such as `SELECT 1 FROM TBL_NAME LIMIT 1'. * Use the multiple-row *Note `INSERT': insert. syntax to reduce communication overhead between the client and the server if you need to insert many rows: INSERT INTO yourtable VALUES (1,2), (5,5), ...; This tip is valid for inserts into any table, not just `InnoDB' tables. * If you often have recurring queries for tables that are not updated frequently, enable the query cache: [mysqld] query_cache_type = 1 query_cache_size = 10M  File: manual.info, Node: innodb-monitors, Next: innodb-troubleshooting, Prev: innodb-tuning, Up: innodb-tuning-troubleshooting 14.6.13.2 `SHOW ENGINE INNODB STATUS' and the `InnoDB' Monitors ............................................................... * Menu: * innodb-standard-monitor:: `InnoDB' Standard Monitor and Lock Monitor Output * innodb-tablespace-monitor:: `InnoDB' Tablespace Monitor Output * innodb-table-monitor:: `InnoDB' Table Monitor Output `InnoDB' Monitors provide information about the `InnoDB' internal state. This information is useful for performance tuning. Each Monitor can be enabled by creating a table with a special name, which causes `InnoDB' to write Monitor output periodically. Also, output for the standard `InnoDB' Monitor is available on demand through the *Note `SHOW ENGINE INNODB STATUS': show-engine. SQL statement. There are several types of `InnoDB' Monitors: * The standard `InnoDB' Monitor displays the following types of information: * Table and record locks held by each active transaction * Lock waits of a transactions * Semaphore waits of threads * Pending file I/O requests * Buffer pool statistics * Purge and insert buffer merge activity of the main `InnoDB' thread For a discussion of `InnoDB' lock modes, see *Note innodb-lock-modes::. To enable the standard `InnoDB' Monitor for periodic output, create a table named `innodb_monitor'. To obtain Monitor output on demand, use the *Note `SHOW ENGINE INNODB STATUS': show-engine. SQL statement to fetch the output to your client program. If you are using the *Note `mysql': mysql. interactive client, the output is more readable if you replace the usual semicolon statement terminator with `\G': mysql> SHOW ENGINE INNODB STATUS\G * The `InnoDB' Lock Monitor is like the standard Monitor but also provides extensive lock information. To enable this Monitor for periodic output, create a table named `innodb_lock_monitor'. * The `InnoDB' Tablespace Monitor prints a list of file segments in the shared tablespace and validates the tablespace allocation data structures. To enable this Monitor for periodic output, create a table named `innodb_tablespace_monitor'. * The `InnoDB' Table Monitor prints the contents of the `InnoDB' internal data dictionary. To enable this Monitor for periodic output, create a table named `innodb_table_monitor'. To enable an `InnoDB' Monitor for periodic output, use a `CREATE TABLE' statement to create the table associated with the Monitor. For example, to enable the standard `InnoDB' Monitor, create the `innodb_monitor' table: CREATE TABLE innodb_monitor (a INT) ENGINE=INNODB; To stop the Monitor, drop the table: DROP TABLE innodb_monitor; The *Note `CREATE TABLE': create-table. syntax is just a way to pass a command to the `InnoDB' engine through MySQL's SQL parser: The only things that matter are the table name `innodb_monitor' and that it be an `InnoDB' table. The structure of the table is not relevant at all for the `InnoDB' Monitor. If you shut down the server, the Monitor does not restart automatically when you restart the server. Drop the Monitor table and issue a new *Note `CREATE TABLE': create-table. statement to start the Monitor. (This syntax may change in a future release.) As of MySQL 5.1.24, the `PROCESS' privilege is required to start or stop the `InnoDB' Monitor tables. When you enable `InnoDB' Monitors for periodic output, `InnoDB' writes their output to the *Note `mysqld': mysqld. server standard error output (`stderr'). In this case, no output is sent to clients. When switched on, `InnoDB' Monitors print data about every 15 seconds. Server output usually is directed to the error log (see *Note error-log::). This data is useful in performance tuning. On Windows, start the server from a command prompt in a console window with the `--console' option if you want to direct the output to the window rather than to the error log. `InnoDB' sends diagnostic output to `stderr' or to files rather than to `stdout' or fixed-size memory buffers, to avoid potential buffer overflows. As a side effect, the output of *Note `SHOW ENGINE INNODB STATUS': show-engine. is written to a status file in the MySQL data directory every fifteen seconds. The name of the file is `innodb_status.PID', where PID is the server process ID. `InnoDB' removes the file for a normal shutdown. If abnormal shutdowns have occurred, instances of these status files may be present and must be removed manually. Before removing them, you might want to examine them to see whether they contain useful information about the cause of abnormal shutdowns. The `innodb_status.PID' file is created only if the configuration option `innodb-status-file=1' is set. `InnoDB' Monitors should be enabled only when you actually want to see Monitor information because output generation does result in some performance decrement. Also, if you enable monitor output by creating the associated table, your error log may become quite large if you forget to remove the table later. For additional information about `InnoDB' monitors, see: * Mark Leith: InnoDB Table and Tablespace Monitors (http://www.markleith.co.uk/?p=25) Each monitor begins with a header containing a timestamp and the monitor name. For example: ================================================ 090407 12:06:19 INNODB TABLESPACE MONITOR OUTPUT ================================================ The header for the standard Monitor (`INNODB MONITOR OUTPUT') is also used for the Lock Monitor because the latter produces the same output with the addition of extra lock information. The following sections describe the output for each Monitor.  File: manual.info, Node: innodb-standard-monitor, Next: innodb-tablespace-monitor, Prev: innodb-monitors, Up: innodb-monitors 14.6.13.3 `InnoDB' Standard Monitor and Lock Monitor Output ........................................................... The Lock Monitor is the same as the standard Monitor except that it includes additional lock information. Enabling either monitor for periodic output by creating the associated `InnoDB' table turns on the same output stream, but the stream includes the extra information if the Lock Monitor is enabled. For example, if you create the `innodb_monitor' and `innodb_lock_monitor' tables, that turns on a single output stream. The stream includes extra lock information until you disable the Lock Monitor by removing the `innodb_lock_monitor' table. Example `InnoDB' Monitor output: mysql> SHOW ENGINE INNODB STATUS\G *************************** 1. row *************************** Status: ===================================== 030709 13:00:59 INNODB MONITOR OUTPUT ===================================== Per second averages calculated from the last 18 seconds ---------- BACKGROUND THREAD ---------- srv_master_thread loops: 53 1_second, 44 sleeps, 5 10_second, 7 background, 7 flush srv_master_thread log flush and writes: 48 ---------- SEMAPHORES ---------- OS WAIT ARRAY INFO: reservation count 413452, signal count 378357 --Thread 32782 has waited at btr0sea.c line 1477 for 0.00 seconds the semaphore: X-lock on RW-latch at 41a28668 created in file btr0sea.c line 135 a writer (thread id 32782) has reserved it in mode wait exclusive number of readers 1, waiters flag 1 Last time read locked in file btr0sea.c line 731 Last time write locked in file btr0sea.c line 1347 Mutex spin waits 0, rounds 0, OS waits 0 RW-shared spins 108462, OS waits 37964; RW-excl spins 681824, OS waits 375485 Spin rounds per wait: 0.00 mutex, 20.00 RW-shared, 0.00 RW-excl ------------------------ LATEST FOREIGN KEY ERROR ------------------------ 030709 13:00:59 Transaction: TRANSACTION 0 290328284, ACTIVE 0 sec, process no 3195, OS thread id 34831 inserting 15 lock struct(s), heap size 2496, undo log entries 9 MySQL thread id 25, query id 4668733 localhost heikki update insert into ibtest11a (D, B, C) values (5, 'khDk' ,'khDk') Foreign key constraint fails for table test/ibtest11a: , CONSTRAINT `0_219242` FOREIGN KEY (`A`, `D`) REFERENCES `ibtest11b` (`A`, `D`) ON DELETE CASCADE ON UPDATE CASCADE Trying to add in child table, in index PRIMARY tuple: 0: len 4; hex 80000101; asc ....;; 1: len 4; hex 80000005; asc ....;; 2: len 4; hex 6b68446b; asc khDk;; 3: len 6; hex 0000114e0edc; asc ...N..;; 4: len 7; hex 00000000c3e0a7; asc .......;; 5: len 4; hex 6b68446b; asc khDk;; But in parent table test/ibtest11b, in index PRIMARY, the closest match we can find is record: RECORD: info bits 0 0: len 4; hex 8000015b; asc ...[;; 1: len 4; hex 80000005; asc ....;; 2: len 3; hex 6b6864; asc khd;; 3: len 6; hex 0000111ef3eb; asc ......;; 4: len 7; hex 800001001e0084; asc .......;; 5: len 3; hex 6b6864; asc khd;; ------------------------ LATEST DETECTED DEADLOCK ------------------------ 030709 12:59:58 *** (1) TRANSACTION: TRANSACTION 0 290252780, ACTIVE 1 sec, process no 3185, OS thread id 30733 inserting LOCK WAIT 3 lock struct(s), heap size 320, undo log entries 146 MySQL thread id 21, query id 4553379 localhost heikki update INSERT INTO alex1 VALUES(86, 86, 794,'aA35818','bb','c79166','d4766t', 'e187358f','g84586','h794',date_format('2001-04-03 12:54:22','%Y-%m-%d %H:%i'),7 *** (1) WAITING FOR THIS LOCK TO BE GRANTED: RECORD LOCKS space id 0 page no 48310 n bits 568 table test/alex1 index symbole trx id 0 290252780 lock mode S waiting Record lock, heap no 324 RECORD: info bits 0 0: len 7; hex 61613335383138; asc aa35818;; 1: *** (2) TRANSACTION: TRANSACTION 0 290251546, ACTIVE 2 sec, process no 3190, OS thread id 32782 inserting 130 lock struct(s), heap size 11584, undo log entries 437 MySQL thread id 23, query id 4554396 localhost heikki update REPLACE INTO alex1 VALUES(NULL, 32, NULL,'aa3572','','c3572','d6012t','', NULL,'h396', NULL, NULL, 7.31,7.31,7.31,200) *** (2) HOLDS THE LOCK(S): RECORD LOCKS space id 0 page no 48310 n bits 568 table test/alex1 index symbole trx id 0 290251546 lock_mode X locks rec but not gap Record lock, heap no 324 RECORD: info bits 0 0: len 7; hex 61613335383138; asc aa35818;; 1: *** (2) WAITING FOR THIS LOCK TO BE GRANTED: RECORD LOCKS space id 0 page no 48310 n bits 568 table test/alex1 index symbole trx id 0 290251546 lock_mode X locks gap before rec insert intention waiting Record lock, heap no 82 RECORD: info bits 0 0: len 7; hex 61613335373230; asc aa35720;; 1: *** WE ROLL BACK TRANSACTION (1) ------------ TRANSACTIONS ------------ Trx id counter 0 290328385 Purge done for trx's n:o < 0 290315608 undo n:o < 0 17 History list length 20 Total number of lock structs in row lock hash table 70 LIST OF TRANSACTIONS FOR EACH SESSION: ---TRANSACTION 0 0, not started, process no 3491, OS thread id 42002 MySQL thread id 32, query id 4668737 localhost heikki show innodb status ---TRANSACTION 0 290328384, ACTIVE 0 sec, process no 3205, OS thread id 38929 inserting 1 lock struct(s), heap size 320 MySQL thread id 29, query id 4668736 localhost heikki update insert into speedc values (1519229,1, 'hgjhjgghggjgjgjgjgjggjgjgjgjgjgggjgjg jlhhgghggggghhjhghgggggghjhghghghghghhhhghghghjhhjghjghjkghjghjghjghjfhjfh ---TRANSACTION 0 290328383, ACTIVE 0 sec, process no 3180, OS thread id 28684 committing 1 lock struct(s), heap size 320, undo log entries 1 MySQL thread id 19, query id 4668734 localhost heikki update insert into speedcm values (1603393,1, 'hgjhjgghggjgjgjgjgjggjgjgjgjgjgggjgj gjlhhgghggggghhjhghgggggghjhghghghghghhhhghghghjhhjghjghjkghjghjghjghjfhjf ---TRANSACTION 0 290328327, ACTIVE 0 sec, process no 3200, OS thread id 36880 starting index read LOCK WAIT 2 lock struct(s), heap size 320 MySQL thread id 27, query id 4668644 localhost heikki Searching rows for update update ibtest11a set B = 'kHdkkkk' where A = 89572 ------- TRX HAS BEEN WAITING 0 SEC FOR THIS LOCK TO BE GRANTED: RECORD LOCKS space id 0 page no 65556 n bits 232 table test/ibtest11a index PRIMARY trx id 0 290328327 lock_mode X waiting Record lock, heap no 1 RECORD: info bits 0 0: len 9; hex 73757072656d756d00; asc supremum.;; ------------------ ---TRANSACTION 0 290328284, ACTIVE 0 sec, process no 3195, OS thread id 34831 rollback of SQL statement ROLLING BACK 14 lock struct(s), heap size 2496, undo log entries 9 MySQL thread id 25, query id 4668733 localhost heikki update insert into ibtest11a (D, B, C) values (5, 'khDk' ,'khDk') ---TRANSACTION 0 290327208, ACTIVE 1 sec, process no 3190, OS thread id 32782 58 lock struct(s), heap size 5504, undo log entries 159 MySQL thread id 23, query id 4668732 localhost heikki update REPLACE INTO alex1 VALUES(86, 46, 538,'aa95666','bb','c95666','d9486t', 'e200498f','g86814','h538',date_format('2001-04-03 12:54:22','%Y-%m-%d %H:%i'), ---TRANSACTION 0 290323325, ACTIVE 3 sec, process no 3185, OS thread id 30733 inserting 4 lock struct(s), heap size 1024, undo log entries 165 MySQL thread id 21, query id 4668735 localhost heikki update INSERT INTO alex1 VALUES(NULL, 49, NULL,'aa42837','','c56319','d1719t','', NULL,'h321', NULL, NULL, 7.31,7.31,7.31,200) -------- FILE I/O -------- I/O thread 0 state: waiting for i/o request (insert buffer thread) I/O thread 1 state: waiting for i/o request (log thread) I/O thread 2 state: waiting for i/o request (read thread) I/O thread 3 state: waiting for i/o request (write thread) Pending normal aio reads: 0, aio writes: 0, ibuf aio reads: 0, log i/o's: 0, sync i/o's: 0 Pending flushes (fsync) log: 0; buffer pool: 0 151671 OS file reads, 94747 OS file writes, 8750 OS fsyncs 25.44 reads/s, 18494 avg bytes/read, 17.55 writes/s, 2.33 fsyncs/s ------------------------------------- INSERT BUFFER AND ADAPTIVE HASH INDEX ------------------------------------- Ibuf for space 0: size 1, free list len 19, seg size 21, 85004 inserts, 85004 merged recs, 26669 merges Hash table size 207619, used cells 14461, node heap has 16 buffer(s) 1877.67 hash searches/s, 5121.10 non-hash searches/s --- LOG --- Log sequence number 18 1212842764 Log flushed up to 18 1212665295 Last checkpoint at 18 1135877290 0 pending log writes, 0 pending chkp writes 4341 log i/o's done, 1.22 log i/o's/second ---------------------- BUFFER POOL AND MEMORY ---------------------- Total memory allocated 84966343; in additional pool allocated 1402624 Buffer pool size 3200 Free buffers 110 Database pages 3074 Modified db pages 2674 Pending reads 0 Pending writes: LRU 0, flush list 0, single page 0 Pages read 171380, created 51968, written 194688 28.72 reads/s, 20.72 creates/s, 47.55 writes/s Buffer pool hit rate 999 / 1000 -------------- ROW OPERATIONS -------------- 0 queries inside InnoDB, 0 queries in queue Main thread process no. 3004, id 7176, state: purging Number of rows inserted 3738558, updated 127415, deleted 33707, read 755779 1586.13 inserts/s, 50.89 updates/s, 28.44 deletes/s, 107.88 reads/s ---------------------------- END OF INNODB MONITOR OUTPUT ============================ `InnoDB' Monitor output is limited to 64,000 bytes when produced using the *Note `SHOW ENGINE INNODB STATUS': show-engine. statement. This limit does not apply to output written to the server's error output. Some notes on the output sections: *`BACKGROUND THREAD'* The `srv_master_thread' lines shows work done by the main background thread. This section is displayed only by `InnoDB Plugin'. *`SEMAPHORES'* This section reports threads waiting for a semaphore and statistics on how many times threads have needed a spin or a wait on a mutex or a rw-lock semaphore. A large number of threads waiting for semaphores may be a result of disk I/O, or contention problems inside `InnoDB'. Contention can be due to heavy parallelism of queries or problems in operating system thread scheduling. Setting the `innodb_thread_concurrency' system variable smaller than the default value might help in such situations. The `Spin rounds per wait' line (`InnoDB Plugin' only) shows the number of spinlock rounds per OS wait for a mutex. *`LATEST FOREIGN KEY ERROR'* This section provides information about the most recent foreign key constraint error. It is not present if no such error has occurred. The contents include the statement that failed as well as information about the constraint that failed and the referenced and referencing tables. *`LATEST DETECTED DEADLOCK'* This section provides information about the most recent deadlock. It is not present if no deadlock has occurred. The contents show which transactions are involved, the statement each was attempting to execute, the locks they have and need, and which transaction `InnoDB' decided to roll back to break the deadlock. The lock modes reported in this section are explained in *Note innodb-lock-modes::. *`TRANSACTIONS'* If this section reports lock waits, your applications might have lock contention. The output can also help to trace the reasons for transaction deadlocks. *`FILE I/O'* This section provides information about threads that `InnoDB' uses to perform various types of I/O. The first few of these are dedicated to general `InnoDB' processing. The contents also display information for pending I/O operations and statistics for I/O performance. On Unix, the number of threads is always 4. On Windows, the number depends on the setting of the `innodb_file_io_threads' system variable. *`INSERT BUFFER AND ADAPTIVE HASH INDEX'* This section shows the status of the `InnoDB' insert buffer and adaptive hash index. (See *Note innodb-insert-buffering::, and *Note innodb-adaptive-hash::.) The contents include the number of operations performed for each, plus statistics for hash index performance. *`LOG'* This section displays information about the `InnoDB' log. The contents include the current log sequence number, how far the log has been flushed to disk, and the position at which `InnoDB' last took a checkpoint. (See *Note innodb-checkpoints::.) The section also displays information about pending writes and write performance statistics. *`BUFFER POOL AND MEMORY'* This section gives you statistics on pages read and written. You can calculate from these numbers how many data file I/O operations your queries currently are doing. For additional information about the operation of the buffer pool, see *Note innodb-buffer-pool::. *`ROW OPERATIONS'* This section shows what the main thread is doing, including the number and performance rate for each type of row operation.  File: manual.info, Node: innodb-tablespace-monitor, Next: innodb-table-monitor, Prev: innodb-standard-monitor, Up: innodb-monitors 14.6.13.4 `InnoDB' Tablespace Monitor Output ............................................ The `InnoDB' Tablespace Monitor prints information about the file segments in the shared tablespace and validates the tablespace allocation data structures. If you use individual tablespaces by enabling `innodb_file_per_table', the Tablespace Monitor does not describe those tablespaces. Example `InnoDB' Tablespace Monitor output: ================================================ 090408 21:28:09 INNODB TABLESPACE MONITOR OUTPUT ================================================ FILE SPACE INFO: id 0 size 13440, free limit 3136, free extents 28 not full frag extents 2: used pages 78, full frag extents 3 first seg id not used 0 23845 SEGMENT id 0 1 space 0; page 2; res 96 used 46; full ext 0 fragm pages 32; free extents 0; not full extents 1: pages 14 SEGMENT id 0 2 space 0; page 2; res 1 used 1; full ext 0 fragm pages 1; free extents 0; not full extents 0: pages 0 SEGMENT id 0 3 space 0; page 2; res 1 used 1; full ext 0 fragm pages 1; free extents 0; not full extents 0: pages 0 ... SEGMENT id 0 15 space 0; page 2; res 160 used 160; full ext 2 fragm pages 32; free extents 0; not full extents 0: pages 0 SEGMENT id 0 488 space 0; page 2; res 1 used 1; full ext 0 fragm pages 1; free extents 0; not full extents 0: pages 0 SEGMENT id 0 17 space 0; page 2; res 1 used 1; full ext 0 fragm pages 1; free extents 0; not full extents 0: pages 0 ... SEGMENT id 0 171 space 0; page 2; res 592 used 481; full ext 7 fragm pages 16; free extents 0; not full extents 2: pages 17 SEGMENT id 0 172 space 0; page 2; res 1 used 1; full ext 0 fragm pages 1; free extents 0; not full extents 0: pages 0 SEGMENT id 0 173 space 0; page 2; res 96 used 44; full ext 0 fragm pages 32; free extents 0; not full extents 1: pages 12 ... SEGMENT id 0 601 space 0; page 2; res 1 used 1; full ext 0 fragm pages 1; free extents 0; not full extents 0: pages 0 NUMBER of file segments: 73 Validating tablespace Validation ok --------------------------------------- END OF INNODB TABLESPACE MONITOR OUTPUT ======================================= The Tablespace Monitor output includes information about the shared tablespace as a whole, followed by a list containing a breakdown for each segment within the tablespace. The tablespace consists of database pages with a default size of 16KB. The pages are grouped into extents of size 1MB (64 consecutive pages). The initial part of the output that displays overall tablespace information has this format: FILE SPACE INFO: id 0 size 13440, free limit 3136, free extents 28 not full frag extents 2: used pages 78, full frag extents 3 first seg id not used 0 23845 Overall tablespace information includes these values: * `id': The tablespace ID. A value of 0 refers to the shared tablespace. * `size': The current tablespace size in pages. * `free limit': The minimum page number for which the free list has not been initialized. Pages at or above this limit are free. * `free extents': The number of free extents. * `not full frag extents', `used pages': The number of fragment extents that are not completely filled, and the number of pages in those extents that have been allocated. * `full frag extents': The number of completely full fragment extents. * `first seg id not used': The first unused segment ID. Individual segment information has this format: SEGMENT id 0 15 space 0; page 2; res 160 used 160; full ext 2 fragm pages 32; free extents 0; not full extents 0: pages 0 Segment information includes these values: `id': The segment ID. `space', `page': The tablespace number and page within the tablespace where the segment `inode' is located. A tablespace number of 0 indicates the shared tablespace. `InnoDB' uses inodes to keep track of segments in the tablespace. The other fields displayed for a segment (`id', `res', and so forth) are derived from information in the inode. `res': The number of pages allocated (reserved) for the segment. `used': The number of allocated pages in use by the segment. `full ext': The number of extents allocated for the segment that are completely used. `fragm pages': The number of initial pages that have been allocated to the segment. `free extents': The number of extents allocated for the segment that are completely unused. `not full extents': The number of extents allocated for the segment that are partially used. `pages': The number of pages used within the not-full extents. When a segment grows, it starts as a single page, and `InnoDB' allocates the first pages for it individually, up to 32 pages (this is the `fragm pages' value). After that, `InnoDB' allocates complete 64-page extents. `InnoDB' can add up to 4 extents at a time to a large segment to ensure good sequentiality of data. For the example segment shown earlier, it has 32 fragment pages, plus 2 full extents (64 pages each), for a total of 160 pages used out of 160 pages allocated. The following segment has 32 fragment pages and one partially full extent using 14 pages for a total of 46 pages used out of 96 pages allocated: SEGMENT id 0 1 space 0; page 2; res 96 used 46; full ext 0 fragm pages 32; free extents 0; not full extents 1: pages 14 It is possible for a segment that has extents allocated to it to have a `fragm pages' value less than 32 if some of the individual pages have been deallocated subsequent to extent allocation.  File: manual.info, Node: innodb-table-monitor, Prev: innodb-tablespace-monitor, Up: innodb-monitors 14.6.13.5 `InnoDB' Table Monitor Output ....................................... The `InnoDB' Table Monitor prints the contents of the `InnoDB' internal data dictionary. The output contains one section per table. The `SYS_FOREIGN' and `SYS_FOREIGN_COLS' sections are for internal data dictionary tables that maintain information about foreign keys. There are also sections for the Table Monitor table and each user-created `InnoDB' table. Suppose that the following two tables have been created in the `test' database: CREATE TABLE parent ( par_id INT NOT NULL, fname CHAR(20), lname CHAR(20), PRIMARY KEY (par_id), UNIQUE INDEX (lname, fname) ) ENGINE = INNODB; CREATE TABLE child ( par_id INT NOT NULL, child_id INT NOT NULL, name VARCHAR(40), birth DATE, weight DECIMAL(10,2), misc_info VARCHAR(255), last_update TIMESTAMP, PRIMARY KEY (par_id, child_id), INDEX (name), FOREIGN KEY (par_id) REFERENCES parent (par_id) ON DELETE CASCADE ON UPDATE CASCADE ) ENGINE = INNODB; Then the Table Monitor output will look something like this (reformatted slightly): =========================================== 090420 12:09:32 INNODB TABLE MONITOR OUTPUT =========================================== -------------------------------------- TABLE: name SYS_FOREIGN, id 0 11, columns 7, indexes 3, appr.rows 1 COLUMNS: ID: DATA_VARCHAR DATA_ENGLISH len 0; FOR_NAME: DATA_VARCHAR DATA_ENGLISH len 0; REF_NAME: DATA_VARCHAR DATA_ENGLISH len 0; N_COLS: DATA_INT len 4; DB_ROW_ID: DATA_SYS prtype 256 len 6; DB_TRX_ID: DATA_SYS prtype 257 len 6; INDEX: name ID_IND, id 0 11, fields 1/6, uniq 1, type 3 root page 46, appr.key vals 1, leaf pages 1, size pages 1 FIELDS: ID DB_TRX_ID DB_ROLL_PTR FOR_NAME REF_NAME N_COLS INDEX: name FOR_IND, id 0 12, fields 1/2, uniq 2, type 0 root page 47, appr.key vals 1, leaf pages 1, size pages 1 FIELDS: FOR_NAME ID INDEX: name REF_IND, id 0 13, fields 1/2, uniq 2, type 0 root page 48, appr.key vals 1, leaf pages 1, size pages 1 FIELDS: REF_NAME ID -------------------------------------- TABLE: name SYS_FOREIGN_COLS, id 0 12, columns 7, indexes 1, appr.rows 1 COLUMNS: ID: DATA_VARCHAR DATA_ENGLISH len 0; POS: DATA_INT len 4; FOR_COL_NAME: DATA_VARCHAR DATA_ENGLISH len 0; REF_COL_NAME: DATA_VARCHAR DATA_ENGLISH len 0; DB_ROW_ID: DATA_SYS prtype 256 len 6; DB_TRX_ID: DATA_SYS prtype 257 len 6; INDEX: name ID_IND, id 0 14, fields 2/6, uniq 2, type 3 root page 49, appr.key vals 1, leaf pages 1, size pages 1 FIELDS: ID POS DB_TRX_ID DB_ROLL_PTR FOR_COL_NAME REF_COL_NAME -------------------------------------- TABLE: name test/child, id 0 14, columns 10, indexes 2, appr.rows 201 COLUMNS: par_id: DATA_INT DATA_BINARY_TYPE DATA_NOT_NULL len 4; child_id: DATA_INT DATA_BINARY_TYPE DATA_NOT_NULL len 4; name: DATA_VARCHAR prtype 524303 len 40; birth: DATA_INT DATA_BINARY_TYPE len 3; weight: DATA_FIXBINARY DATA_BINARY_TYPE len 5; misc_info: DATA_VARCHAR prtype 524303 len 255; last_update: DATA_INT DATA_UNSIGNED DATA_BINARY_TYPE DATA_NOT_NULL len 4; DB_ROW_ID: DATA_SYS prtype 256 len 6; DB_TRX_ID: DATA_SYS prtype 257 len 6; INDEX: name PRIMARY, id 0 17, fields 2/9, uniq 2, type 3 root page 52, appr.key vals 201, leaf pages 5, size pages 6 FIELDS: par_id child_id DB_TRX_ID DB_ROLL_PTR name birth weight misc_info last_update INDEX: name name, id 0 18, fields 1/3, uniq 3, type 0 root page 53, appr.key vals 210, leaf pages 1, size pages 1 FIELDS: name par_id child_id FOREIGN KEY CONSTRAINT test/child_ibfk_1: test/child ( par_id ) REFERENCES test/parent ( par_id ) -------------------------------------- TABLE: name test/innodb_table_monitor, id 0 15, columns 4, indexes 1, appr.rows 0 COLUMNS: i: DATA_INT DATA_BINARY_TYPE len 4; DB_ROW_ID: DATA_SYS prtype 256 len 6; DB_TRX_ID: DATA_SYS prtype 257 len 6; INDEX: name GEN_CLUST_INDEX, id 0 19, fields 0/4, uniq 1, type 1 root page 193, appr.key vals 0, leaf pages 1, size pages 1 FIELDS: DB_ROW_ID DB_TRX_ID DB_ROLL_PTR i -------------------------------------- TABLE: name test/parent, id 0 13, columns 6, indexes 2, appr.rows 299 COLUMNS: par_id: DATA_INT DATA_BINARY_TYPE DATA_NOT_NULL len 4; fname: DATA_CHAR prtype 524542 len 20; lname: DATA_CHAR prtype 524542 len 20; DB_ROW_ID: DATA_SYS prtype 256 len 6; DB_TRX_ID: DATA_SYS prtype 257 len 6; INDEX: name PRIMARY, id 0 15, fields 1/5, uniq 1, type 3 root page 50, appr.key vals 299, leaf pages 2, size pages 3 FIELDS: par_id DB_TRX_ID DB_ROLL_PTR fname lname INDEX: name lname, id 0 16, fields 2/3, uniq 2, type 2 root page 51, appr.key vals 300, leaf pages 1, size pages 1 FIELDS: lname fname par_id FOREIGN KEY CONSTRAINT test/child_ibfk_1: test/child ( par_id ) REFERENCES test/parent ( par_id ) ----------------------------------- END OF INNODB TABLE MONITOR OUTPUT ================================== For each table, Table Monitor output contains a section that displays general information about the table and specific information about its columns, indexes, and foreign keys. The general information for each table includes the table name (in `DB_NAME/TBL_NAME' format except for internal tables), its ID, the number of columns and indexes, and an approximate row count. The `COLUMNS' part of a table section lists each column in the table. Information for each column indicates its name and data type characteristics. Some internal columns are added by `InnoDB', such as `DB_ROW_ID' (row ID), `DB_TRX_ID' (transaction ID), and `DB_ROLL_PTR' (a pointer to the rollback/undo data). * `DATA_XXX': These symbols indicate the data type. There may be multiple `DATA_XXX' symbols for a given column. * `prtype': The column's `precise' type. This field includes information such as the column data type, character set code, nullability, signedness, and whether it is a binary string. This field is described in the `innobase/include/data0type.h' source file. * `len': The column length in bytes. Each `INDEX' part of the table section provides the name and characteristics of one table index: * `name': The index name. If the name is `PRIMARY', the index is a primary key. If the name is `GEN_CLUST_INDEX', the index is the clustered index that is created automatically if the table definition doesn't include a primary key or non-`NULL' unique index. See *Note innodb-index-types::. * `id': The index ID. * `fields': The number of fields in the index, as a value in `M/N' format: * M is the number of user-defined columns; that is, the number of columns you would see in the index definition in a `CREATE TABLE' statement. * N is the total number of index columns, including those added internally. For the clustered index, the total includes the other columns in the table definition, plus any columns added internally. For a secondary index, the total includes the columns from the primary key that are not part of the secondary index. * `uniq': The number of leading fields that are enough to determine index values uniquely. * `type': The index type. This is a bit field. For example, 1 indicates a clustered index and 2 indicates a unique index, so a clustered index (which always contains unique values), will have a `type' value of 3. An index with a `type' value of 0 is neither clustered nor unique. The flag values are defined in the `innobase/include/dict0mem.h' source file. * `root page': The index root page number. * `appr. key vals': The approximate index cardinality. * `leaf pages': The approximate number of leaf pages in the index. * `size pages': The approximate total number of pages in the index. * `FIELDS': The names of the fields in the index. For a clustered index that was generated automatically, the field list begins with the internal `DB_ROW_ID' (row ID) field. `DB_TRX_ID' and `DB_ROLL_PTR' are always added internally to the clustered index, following the fields that comprise the primary key. For a secondary index, the final fields are those from the primary key that are not part of the secondary index. The end of the table section lists the `FOREIGN KEY' definitions that apply to the table. This information appears whether the table is a referencing or referenced table.  File: manual.info, Node: innodb-troubleshooting, Next: innodb-troubleshooting-datadict, Prev: innodb-monitors, Up: innodb-tuning-troubleshooting 14.6.13.6 `InnoDB' General Troubleshooting .......................................... The following general guidelines apply to troubleshooting `InnoDB' problems: * When an operation fails or you suspect a bug, look at the MySQL server error log (see *Note error-log::). * Issues relating to the `InnoDB' data dictionary include failed *Note `CREATE TABLE': create-table. statements (orphaned table files), inability to open `.InnoDB' files, and `system cannot find the path specified' errors. For information about these sorts of problems and errors, see *Note innodb-troubleshooting-datadict::. * When troubleshooting, it is usually best to run the MySQL server from the command prompt, rather than through *Note `mysqld_safe': mysqld-safe. or as a Windows service. You can then see what *Note `mysqld': mysqld. prints to the console, and so have a better grasp of what is going on. On Windows, start *Note `mysqld': mysqld. with the `--console' option to direct the output to the console window. * Use the `InnoDB' Monitors to obtain information about a problem (see *Note innodb-monitors::). If the problem is performance-related, or your server appears to be hung, you should use the standard Monitor to print information about the internal state of `InnoDB'. If the problem is with locks, use the Lock Monitor. If the problem is in creation of tables or other data dictionary operations, use the Table Monitor to print the contents of the `InnoDB' internal data dictionary. To see tablespace information use the Tablespace Monitor. * If you suspect that a table is corrupt, run *Note `CHECK TABLE': check-table. on that table.  File: manual.info, Node: innodb-troubleshooting-datadict, Prev: innodb-troubleshooting, Up: innodb-tuning-troubleshooting 14.6.13.7 Troubleshooting `InnoDB' Data Dictionary Operations ............................................................. A specific issue with tables is that the MySQL server keeps data dictionary information in `.frm' files it stores in the database directories, whereas `InnoDB' also stores the information into its own data dictionary inside the tablespace files. If you move `.frm' files around, or if the server crashes in the middle of a data dictionary operation, the locations of the `.frm' files may end up out of synchrony with the locations recorded in the `InnoDB' internal data dictionary. A symptom of an out-of-sync data dictionary is that a *Note `CREATE TABLE': create-table. statement fails. If this occurs, look in the server's error log. If the log says that the table already exists inside the `InnoDB' internal data dictionary, you have an orphaned table inside the `InnoDB' tablespace files that has no corresponding `.frm' file. The error message looks like this: InnoDB: Error: table test/parent already exists in InnoDB internal InnoDB: data dictionary. Have you deleted the .frm file InnoDB: and not used DROP TABLE? Have you used DROP DATABASE InnoDB: for InnoDB tables in MySQL version <= 3.23.43? InnoDB: See the Restrictions section of the InnoDB manual. InnoDB: You can drop the orphaned table inside InnoDB by InnoDB: creating an InnoDB table with the same name in another InnoDB: database and moving the .frm file to the current database. InnoDB: Then MySQL thinks the table exists, and DROP TABLE will InnoDB: succeed. You can drop the orphaned table by following the instructions given in the error message. If you are still unable to use *Note `DROP TABLE': drop-table. successfully, the problem may be due to name completion in the *Note `mysql': mysql. client. To work around this problem, start the *Note `mysql': mysql. client with the `--skip-auto-rehash' option and try *Note `DROP TABLE': drop-table. again. (With name completion on, *Note `mysql': mysql. tries to construct a list of table names, which fails when a problem such as just described exists.) Another symptom of an out-of-sync data dictionary is that MySQL prints an error that it cannot open a `.InnoDB' file: ERROR 1016: Can't open file: 'child2.InnoDB'. (errno: 1) In the error log you can find a message like this: InnoDB: Cannot find table test/child2 from the internal data dictionary InnoDB: of InnoDB though the .frm file for the table exists. Maybe you InnoDB: have deleted and recreated InnoDB data files but have forgotten InnoDB: to delete the corresponding .frm files of InnoDB tables? This means that there is an orphaned `.frm' file without a corresponding table inside `InnoDB'. You can drop the orphaned `.frm' file by deleting it manually. If MySQL crashes in the middle of an *Note `ALTER TABLE': alter-table. operation, you may end up with an orphaned temporary table inside the `InnoDB' tablespace. Using the Table Monitor, you can see listed a table with a name that begins with `#sql-'. You can perform SQL statements on tables whose name contains the character ``#'' if you enclose the name within backticks. Thus, you can drop such an orphaned table like any other orphaned table using the method described earlier. To copy or rename a file in the Unix shell, you need to put the file name in double quotation marks if the file name contains ``#''. With `innodb_file_per_table' enabled, the following message might occur if the `.frm' or `.ibd' files (or both) are missing: InnoDB: in InnoDB data dictionary has tablespace id N, InnoDB: but tablespace with that id or name does not exist. Have InnoDB: you deleted or moved .ibd files? InnoDB: This may also be a table created with CREATE TEMPORARY TABLE InnoDB: whose .ibd and .frm files MySQL automatically removed, but the InnoDB: table still exists in the InnoDB internal data dictionary. If this occurs, try the following procedure to resolve the problem: 1. Create a matching `.frm' file in some other database directory and copy it to the database directory where the orphan table is located. 2. Issue *Note `DROP TABLE': drop-table. for the original table. That should successfully drop the table and `InnoDB' should print a warning to the error log that the `.ibd' file was missing.  File: manual.info, Node: innodb-restrictions, Prev: innodb-tuning-troubleshooting, Up: innodb-storage-engine 14.6.14 Restrictions on `InnoDB' Tables --------------------------------------- *Warning*: Do _not_ convert MySQL system tables in the `mysql' database from `MyISAM' to `InnoDB' tables! This is an unsupported operation. If you do this, MySQL does not restart until you restore the old system tables from a backup or re-generate them with the *Note `mysql_install_db': mysql-install-db. script. *Warning*: It is not a good idea to configure `InnoDB' to use data files or log files on NFS volumes. Otherwise, the files might be locked by other processes and become unavailable for use by MySQL. * Maximums and Minimums * * A table cannot contain more than 1000 columns. * The `InnoDB' internal maximum key length is 3500 bytes, but MySQL itself restricts this to 3072 bytes. * Index key prefixes can be up to 767 bytes. See *Note create-index::. * The maximum row length, except for variable-length columns (*Note `VARBINARY': binary-varbinary, *Note `VARCHAR': char, *Note `BLOB': blob. and *Note `TEXT': blob.), is slightly less than half of a database page. That is, the maximum row length is about 8000 bytes. *Note `LONGBLOB': blob. and *Note `LONGTEXT': blob. columns must be less than 4GB, and the total row length, including *Note `BLOB': blob. and *Note `TEXT': blob. columns, must be less than 4GB. If a row is less than half a page long, all of it is stored locally within the page. If it exceeds half a page, variable-length columns are chosen for external off-page storage until the row fits within half a page, as described in *Note innodb-file-space::. * Although `InnoDB' supports row sizes larger than 65,535 bytes internally, MySQL inself imposes a row-size limit of 65,535 for the combined size of all columns: mysql> CREATE TABLE t (a VARCHAR(8000), b VARCHAR(10000), -> c VARCHAR(10000), d VARCHAR(10000), e VARCHAR(10000), -> f VARCHAR(10000), g VARCHAR(10000)) ENGINE=InnoDB; ERROR 1118 (42000): Row size too large. The maximum row size for the used table type, not counting BLOBs, is 65535. You have to change some columns to TEXT or BLOBs See *Note column-count-limit::. * On some older operating systems, files must be less than 2GB. This is not a limitation of `InnoDB' itself, but if you require a large tablespace, you will need to configure it using several smaller data files rather than one or a file large data files. * The combined size of the `InnoDB' log files must be less than 4GB. * The minimum tablespace size is 10MB. The maximum tablespace size is four billion database pages (64TB). This is also the maximum size for a table. * Index Types * * `InnoDB' tables do not support `FULLTEXT' indexes. * `InnoDB' tables support spatial data types, but not indexes on them. * *Note `ANALYZE TABLE': analyze-table. determines index cardinality (as displayed in the `Cardinality' column of *Note `SHOW INDEX': show-index. output) by doing eight random dives to each of the index trees and updating index cardinality estimates accordingly. Because these are only estimates, repeated runs of *Note `ANALYZE TABLE': analyze-table. may produce different numbers. This makes *Note `ANALYZE TABLE': analyze-table. fast on `InnoDB' tables but not 100% accurate because it does not take all rows into account. For `InnoDB Plugin', the number of random dives can be changed by modifying the `innodb_stats_sample_pages' system variable. For more information, see Ease of Use and Reliability. MySQL uses index cardinality estimates only in join optimization. If some join is not optimized in the right way, you can try using *Note `ANALYZE TABLE': analyze-table. In the few cases that *Note `ANALYZE TABLE': analyze-table. does not produce values good enough for your particular tables, you can use `FORCE INDEX' with your queries to force the use of a particular index, or set the `max_seeks_for_key' system variable to ensure that MySQL prefers index lookups over table scans. See *Note server-system-variables::, and *Note optimizer-issues::. * *Note `SHOW TABLE STATUS': show-table-status. does not give accurate statistics on `InnoDB' tables, except for the physical size reserved by the table. The row count is only a rough estimate used in SQL optimization. * `InnoDB' does not keep an internal count of rows in a table. (In practice, this would be somewhat complicated due to multi-versioning.) To process a `SELECT COUNT(*) FROM t' statement, `InnoDB' must scan an index of the table, which takes some time if the index is not entirely in the buffer pool. If your table does not change often, using the MySQL query cache is a good solution. To get a fast count, you have to use a counter table you create yourself and let your application update it according to the inserts and deletes it does. *Note `SHOW TABLE STATUS': show-table-status. also can be used if an approximate row count is sufficient. See *Note innodb-tuning::. * On Windows, `InnoDB' always stores database and table names internally in lowercase. To move databases in a binary format from Unix to Windows or from Windows to Unix, create all databases and tables using lowercase names. * For an `AUTO_INCREMENT' column, you must always define an index for the table, and that index must contain just the `AUTO_INCREMENT' column. In `MyISAM' tables, the `AUTO_INCREMENT' column may be part of a multi-column index. * While initializing a previously specified `AUTO_INCREMENT' column on a table, `InnoDB' sets an exclusive lock on the end of the index associated with the `AUTO_INCREMENT' column. In accessing the auto-increment counter, `InnoDB' uses a specific table lock mode `AUTO-INC' where the lock lasts only to the end of the current SQL statement, not to the end of the entire transaction. Other clients cannot insert into the table while the `AUTO-INC' table lock is held; see *Note innodb-auto-increment-handling::. * When you restart the MySQL server, `InnoDB' may reuse an old value that was generated for an `AUTO_INCREMENT' column but never stored (that is, a value that was generated during an old transaction that was rolled back). * When an `AUTO_INCREMENT' integer column runs out of values, a subsequent `INSERT' operation returns a duplicate-key error. This is general MySQL behavior, similar to how `MyISAM' works. * `DELETE FROM TBL_NAME' does not regenerate the table but instead deletes all rows, one by one. * Under some conditions, `TRUNCATE TBL_NAME' for an `InnoDB' table is mapped to `DELETE FROM TBL_NAME'. See *Note truncate-table::. * In MySQL 5.1, the MySQL *Note `LOCK TABLES': lock-tables. operation acquires two locks on each table if `innodb_table_locks = 1' (the default). In addition to a table lock on the MySQL layer, it also acquires an `InnoDB' table lock. Older versions of MySQL did not acquire `InnoDB' table locks; the old behavior can be selected by setting `innodb_table_locks = 0'. If no `InnoDB' table lock is acquired, *Note `LOCK TABLES': lock-tables. completes even if some records of the tables are being locked by other transactions. * All `InnoDB' locks held by a transaction are released when the transaction is committed or aborted. Thus, it does not make much sense to invoke *Note `LOCK TABLES': lock-tables. on `InnoDB' tables in `autocommit = 1' mode, because the acquired `InnoDB' table locks would be released immediately. * You cannot lock additional tables in the middle of a transaction, because *Note `LOCK TABLES': lock-tables. performs an implicit *Note `COMMIT': commit. and *Note `UNLOCK TABLES': lock-tables. An `InnoDB' variant of *Note `LOCK TABLES': lock-tables. has been planned that can be executed in the middle of a transaction. * The *Note `LOAD TABLE FROM MASTER': load-table-from-master. statement for setting up replication slave servers does not work for `InnoDB' tables. A workaround is to alter the table to `MyISAM' on the master, then do the load, and after that alter the master table back to `InnoDB'. Do not do this if the tables use `InnoDB'-specific features such as foreign keys. * The default database page size in `InnoDB' is 16KB. By recompiling the code, you can set it to values ranging from 8KB to 64KB. You must update the values of `UNIV_PAGE_SIZE' and `UNIV_PAGE_SIZE_SHIFT' in the `univ.i' source file. *Note*: Changing the page size is not a supported operation and there is no guarantee that *Note `InnoDB': innodb-storage-engine. will function normally with a page size other than 16KB. Problems compiling or running InnoDB may occur. In particular, `ROW_FORMAT=COMPRESSED' in the `InnoDB Plugin' assumes that the page size is at most 16KB and uses 14-bit pointers. A version of *Note `InnoDB': innodb-storage-engine. built for one page size cannot use data files or log files from a version built for a different page size. * Currently, cascaded foreign key actions to not activate triggers. * You cannot create a table with a column name that matches the name of an internal InnoDB column (including `DB_ROW_ID', `DB_TRX_ID', `DB_ROLL_PTR', and `DB_MIX_ID'). In versions of MySQL before 5.1.10 this would cause a crash, since 5.1.10 the server will report error 1005 and refers to error -1 in the error message. This limitation applies only to use of the names in uppercase. * `InnoDB' has a limit of 1023 concurrent transactions that have created undo records by modifying data. Workarounds include keeping transactions as small and fast as possible, delaying changes until near the end of the transaction, and using stored routines to reduce client/server latency delays. Applications should commit transactions before doing time-consuming client-side operations.  File: manual.info, Node: se-db2, Next: merge-storage-engine, Prev: innodb-storage-engine, Up: storage-engines 14.7 The `IBMDB2I' Storage Engine ================================= * Menu: * se-db2-installation:: Installation * se-db2-configuration:: Configuration Options * se-db2-creating-tables:: Creating schemas and tables * se-db2-metadata:: Database/metadata management * se-db2-transactions:: Transaction behavior * se-db2-terms:: Principles and Terminology * se-db2-notes:: Notes and Limitations * se-db2-collations:: Character sets and collations * se-db2-errors:: Error codes and trouble-shooting information The `IBMDB2I' storage engine is designed as a fully featured transaction-capable storage engine that enables MySQL to store its data in DB2 tables running on IBM i. With the `IBMDB2I' storage engine, data can be shared between MySQL applications and applications coded for native DB2 for i interfaces. `IBMDB2I' provides ACID-compliant transactions, support for foreign key constraints, full crash recovery, radix-tree-based indexes, and the unique ability to enable DB2 for i applications to see and update table data in real time. More information about the storage engine and its interaction with DB2 for i can be found in IBM's _Using DB2 for i as a Storage Engine for MySQL_ Redbook publication, at IBM DB2 for i a Storage Engine for MySQL Redbook (http://www.redbooks.ibm.com/abstracts/sg247705.html). *Note*: The `IBMDB2I' storage engine was introduced in MySQL 5.1.33 and considered GA in MySQL 5.1.35. It was removed in MySQL 5.1.54.  File: manual.info, Node: se-db2-installation, Next: se-db2-configuration, Prev: se-db2, Up: se-db2 14.7.1 Installation ------------------- Because it relies on features specific to the IBM i operating system running on IBM Power systems, the `IBMDB2I' storage engine is only available on builds of MySQL specifically created for the IBM i operating system. IBM i 5.4 or later is required to run ``IBMDB2I''. Some features may require IBM i 6.1 or later versions. As well, a set of program temporary fixes (PTFs) must be installed. Information about the specific PTF numbers can be obtained from http://www-912.ibm.com/n_dir/nas4apar.nsf/c79815e083182fec862564c00079d117/67d12878076e4827862574e2003c6d4a?OpenDocument (http://www-912.ibm.com/n_dir/nas4apar.nsf/c79815e083182fec862564c00079d117/67d12878076e4827862574e2003c6d4a?OpenDocument). The engine is built as a dynamic plugin and so must be installed by using the following command: mysql> INSTALL PLUGIN ibmdb2i SONAME ha_ibmdb2i.so;  File: manual.info, Node: se-db2-configuration, Next: se-db2-creating-tables, Prev: se-db2-installation, Up: se-db2 14.7.2 Configuration Options ---------------------------- *`IBMDB2I' Storage Engine Features* Name Cmd-Line Option file System Var Status Var Var Scope Dynamic ibmdb2i_assume_exclusive_useYes Yes Yes Global Yes ibmdb2i_async_enabledYes Yes Yes Both Yes ibmdb2i_compat_opt_allow_zero_date_valsYes Yes Yes Both Yes ibmdb2i_compat_opt_blob_colsYes Yes Yes Both Yes ibmdb2i_compat_opt_time_as_durationYes Yes Yes Both Yes ibmdb2i_compat_opt_year_as_intYes Yes Yes Both Yes ibmdb2i_create_index_optionYes Yes Yes Both Yes ibmdb2i_lob_alloc_sizeYes Yes Yes Both Yes ibmdb2i_max_read_buffer_sizeYes Yes Yes Both Yes ibmdb2i_max_write_buffer_sizeYes Yes Yes Both Yes ibmdb2i_propogate_default_col_valsYes Yes Yes Both Yes ibmdb2i_rdb_nameYes Yes Yes Global No ibmdb2i_system_trace_levelYes Yes Yes Global Yes ibmdb2i_transaction_unsafeYes Yes Yes Both Yes * `ibmdb2i_assume_exclusive_use' Options for ibmdb2i_assume_exclusive_use *Version Introduced* 5.1.33 *Command-Line `ibmdb2i_assume_exclusive_use' Format* *Option-File Format* `ibmdb2i_assume_exclusive_use' *Variable Name* `ibmdb2i_assume_exclusive_use' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* (ibmsystemi) `boolean' *Default* `off' Specifies whether an external interface (such as DB2 for i) may be altering the data accessible by the `IBMDB2I' engine. This is an advisory value that may improve performance when correctly set to ON. When the value is ON, `IBMDB2I' may perform some internal caching of table statistics. When the value is set to OFF, `IBMDB2I' must assume that the table rows could be inserted and deleted without its direct knowledge and must call DB2 to obtain accurate statistics before each operation. Default Value: OFF * `ibmdb2i_async_enabled' Options for ibmdb2i_async_enabled *Version Introduced* 5.1.33 *Command-Line `ibmdb2i_async_enabled' Format* *Option-File Format* `ibmdb2i_async_enabled' *Variable Name* `ibmdb2i_async_enabled' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* (ibmsystemi) `boolean' *Default* `on' Specifies whether buffering between `IBMDB2I' and the QSQSRVR jobs responsible for fetching row data should be done in an asynchronous manner. Asynchronous reads are enabled by default and provide optimal performance.Under normal circumstances, this value will never need to be modified. Default Value: ON * `ibmdb2i_create_index_option' Options for ibmdb2i_create_index_option *Version Introduced* 5.1.33 *Command-Line `ibmdb2i_create_index_option' Format* *Option-File Format* `ibmdb2i_create_index_option' *Variable Name* `ibmdb2i_create_index_option' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* (ibmsystemi) `numeric' *Default* `0' Controls whether additional indexes are created for use by traditional DB2 for i interfaces. When the value is 0, no additional indexes will be created. When the value is 1 and the index created on behalf of MySQL is ASCII-based, an additional index is created based on EBCDIC hexadecimal sorting. The additional index may be useful for traditional DB2 for i interfaces which expect indexes to use EBCDIC-based sort sequences. Default Value: 0 * `ibmdb2i_compat_opt_time_as_duration' Options for ibmdb2i_compat_opt_time_as_duration *Version Introduced* 5.1.33 *Command-Line `ibmdb2i_compat_opt_time_as_duration' Format* *Option-File Format* `ibmdb2i_compat_opt_time_as_duration' *Variable Name* `ibmdb2i_compat_opt_time_as_duration' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* (ibmsystemi) `boolean' *Default* `off' Controls how MySQL TIME columns are mapped to DB2 data types when creating or altering an `IBMDB2I' table. When the value is `ON', the column is mapped to an `INTEGER' type in DB2 and supports the full range of values defined by MySQL for `TIME' types. When the value is `OFF', the column is mapped to a DB2 `TIME' type and supports values in the range of '00:00:00' to '23:59:59'. This option is provided to provide enhanced interoperability with DB2 for i interfaces. Default Value: OFF * `ibmdb2i_system_trace_level' Options for ibmdb2i_system_trace_level *Version Introduced* 5.1.33 *Command-Line `ibmdb2i_system_trace_level' Format* *Option-File Format* `ibmdb2i_system_trace_level' *Variable Name* `ibmdb2i_system_trace_level' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* (ibmsystemi) `boolean' *Default* `0' Specifies what kind of debugging information is to be gathered for `QSQSRVR' jobs servicing MySQL connections. Multiple sources of information may be specified by summing the respective values. Changes to this option only affect new connections. Valid values include * `0': No information (Default) * `2': `STRDBMON' * `4': `STRDBG' * `8': `DSPJOBLOG' * `16': `STRTRC' * `32': `PRTSQLINF' The most useful sources of information are `DSPJOBLOG', which will capture the job log for each `QSQSRVR' job in a spoolfile, and `STRDBG', which will increase the diagnostic information in each job log. Default Value: 0 * `ibmdb2i_compat_opt_allow_zero_date_vals' Options for ibmdb2i_compat_opt_allow_zero_date_vals *Version Introduced* 5.1.33 *Command-Line `ibmdb2i_compat_opt_allow_zero_date_vals' Format* *Option-File Format* `ibmdb2i_compat_opt_allow_zero_date_vals' *Variable Name* `ibmdb2i_compat_opt_allow_zero_date_vals' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* (ibmsystemi) `boolean' *Default* `0' Specifies whether the storage engine should permit the `0000-00-00' date in `DATETIME', `TIMESTAMP' and `DATE' columns. When the option is 0, attempts to insert a row containing this zero date into an `IBMDB2I' table will fail. As well, a warning will be generated when creating a column with this zero value as the default value. When this option is 1, the zero value will be subsituted with `0001-01-01' when stored in DB2, and a `0001-01-01' value will be translated to `0000-00-00' when read from DB2. Similarly, when a column with a default zero value is created, the DB2 default value will be '0001-01-01'. Users must be aware that, when this option is 1, all values of `0001-01-01' in DB2 will be interpreted as `0000-00-00'. This option is primarily added for compatibility with applications which rely on the zero date. Default Value: 0 * `ibmdb2i_propagate_default_col_vals' Options for ibmdb2i_propogate_default_col_vals *Version Introduced* 5.1.33 *Command-Line `ibmdb2i_propogate_default_col_vals' Format* *Option-File Format* `ibmdb2i_propogate_default_col_vals' *Variable Name* `ibmdb2i_propogate_default_col_vals' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* (ibmsystemi) `boolean' *Default* `on' Specifies whether `DEFAULT' value associated with each column should be propagated to the DB2 definition of the table when a table is created or altered. The default value is ON. This ensures that rows inserted from a standard DB2 interface will use the same default values as when inserted from MySQL. Default Value: ON * `ibmdb2i_compat_opt_year_as_int' Options for ibmdb2i_compat_opt_year_as_int *Version Introduced* 5.1.33 *Command-Line `ibmdb2i_compat_opt_year_as_int' Format* *Option-File Format* `ibmdb2i_compat_opt_year_as_int' *Variable Name* `ibmdb2i_compat_opt_year_as_int' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* (ibmsystemi) `boolean' *Default* `0' Controls how YEAR columns are stored in DB2. The default is 0 and causes `YEAR' columns to be created as `CHAR(4) CCSID 1208' columns in DB2. Setting this option to 1 causes the YEAR columns to be created as `SMALLINT' columns. This provides a slight performance increase and enables indexes that combine a `YEAR' column with a character column. Default Value: 0 * `ibmdb2i_lob_alloc_size' Options for ibmdb2i_lob_alloc_size *Version Introduced* 5.1.33 *Command-Line `ibmdb2i_lob_alloc_size' Format* *Option-File Format* `ibmdb2i_lob_alloc_size' *Variable Name* `ibmdb2i_lob_alloc_size' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* (ibmsystemi) `numeric' *Default* `2MB' Controls how much space is allocated by default for reading data from a `BLOB' or `TEXT' field. If an application consistently uses `BLOB' or `TEXT' fields that contain more than 2 MB of data, read performance may be improved if this value is increased. Conversely, an application which uses smaller `BLOB' or `TEXT' fields may find that the MySQL memory footprint is reduced if a smaller value is specified for this option. Default Value: 2 MB * `ibmdb2i_compat_opt_blob_cols' Options for ibmdb2i_compat_opt_blob_cols *Version Introduced* 5.1.33 *Command-Line `ibmdb2i_compat_opt_blob_cols' Format* *Option-File Format* `ibmdb2i_compat_opt_blob_cols' *Variable Name* `ibmdb2i_compat_opt_blob_cols' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* (ibmsystemi) `numeric' *Default* `0' Specifies how MySQL `TEXT' and `BLOB' columns larger than 255 characters are mapped when creating `IBMDB2I' tables. When the value is 0, `TEXT' columns are mapped to `CLOB' or `DBCLOB' columns for DB2 for i. This enables the column to contain the maximum size documented for `TEXT' columns (64K characters), but the column can not be included in an index. When the value is 1, `TEXT' columns are mapped to `LONG VARCHAR'/`VARGRAPHIC' columns, and `BLOB' columns are mapped to `LONG VARBINARY'. This permits indexes to be created over the column, but it reduces the amount of storage available to the column below the documented maximum for `TEXT' columns. This option was provided to enable applications which relied on the ability to create prefix indexes over `TEXT' columns. Default Value: 0 * `ibmdb2i_max_read_buffer_size' Options for ibmdb2i_max_read_buffer_size *Version Introduced* 5.1.33 *Command-Line `ibmdb2i_max_read_buffer_size' Format* *Option-File Format* `ibmdb2i_max_read_buffer_size' *Variable Name* `ibmdb2i_max_read_buffer_size' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* (ibmsystemi) `numeric' *Default* `1MB' Controls the maximum amount of memory allocated for buffering row data when doing reads from an `IBMDB2I' table. This buffering is done independently of any row buffering done within MySQL proper. Setting this value too low may reduce read performance, while setting it too high may increase memory usage and may also reduce read performance. Default Value: 1 MB * `ibmdb2i_max_write_buffer_size' Options for ibmdb2i_max_write_buffer_size *Version Introduced* 5.1.33 *Command-Line `ibmdb2i_max_write_buffer_size' Format* *Option-File Format* `ibmdb2i_max_write_buffer_size' *Variable Name* `ibmdb2i_max_write_buffer_size' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* (ibmsystemi) `numeric' *Default* `8MB' Controls the maximum amount of memory allocated for buffering row data when inserting multiple rows into an `IBMDB2I' table. This buffering is done independently of any row buffering done within MySQL proper. Setting this value too low may reduce write performance, while setting it too high may increase memory usage. Default Value: 8 MB * `ibmdb2i_rdb_name' Options for ibmdb2i_rdb_name *Version Introduced* 5.1.33 *Command-Line `ibmdb2i_rdb_name' Format* *Option-File Format* `ibmdb2i_rdb_name' *Variable Name* `ibmdb2i_rdb_name' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* (ibmsystemi) `string' *Default* `' The name of a local DB2 for i relational database that will act as a container for all `IBMDB2I' tables. This enables an independent auxiliary storage pool (IASP) to be selected for usage. If no value is specified, the system database (*SYSBAS) is used. Default Value: * `ibmdb2i_transaction_unsafe' Options for ibmdb2i_transaction_unsafe *Version Introduced* 5.1.33 *Command-Line `ibmdb2i_transaction_unsafe' Format* *Option-File Format* `ibmdb2i_transaction_unsafe' *Variable Name* `ibmdb2i_transaction_unsafe' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* (ibmsystemi) `boolean' *Default* `off' Controls whether `IBMDB2I' honors the transactional commands and isolation levels specified for MySQL. If the value is OFF, transactions are fully supported. If the value is ON, transactional behavior is not implemented. This may provide a moderate performance increase for applications that do not rely on transactional guarantees. Default Value: OFF The values specified for `ibmdb2i_create_index_option', `ibmdb2i_create_time_columns_as_tod', `ibmdb2i_map_blob_to_varchar', `ibmdb2i_compat_opt_allow_zero_date_vals', `ibmdb2i_propagate_default_col_vals', and `ibmdb2i_propagate_default_col_val' will be applied whenever an `IBMDB2I' table is created. Tables are implicitly destroyed and re-created when an `offline' `ALTER TABLE' is performed on an `IBMDB2I' table. Therefore it is highly recommended that the values of these variables be consistent across the lifetime of a table to prevent an `ALTER TABLE' from running under a different set of options than were used to originally create the table. If this recommendation is not followed, the `ALTER TABLE' may fail upon encountering incompatible data when re-creating the table.  File: manual.info, Node: se-db2-creating-tables, Next: se-db2-metadata, Prev: se-db2-configuration, Up: se-db2 14.7.3 Creating schemas and tables ---------------------------------- * Menu: * se-db2-creating-tables-identifiers:: Identifier names * se-db2-creating-tables-indexnames:: Index names `IBMDB2I' tables are created by specifying the `ENGINE=IBMDB2I' option on a `CREATE TABLE' or `ALTER TABLE' statement. These tables are stored as DB2 for i objects in the QSYS.LIB file system. Therefore, in contrast to the behavior of other storage engines, `IBMDB2I' table and index data does not reside beneath the datadir directory with other MySQL table data. When the first `IBMDB2I' table is created in a MySQL schema, the corresponding DB2 schema will be created (if it does not already exist). Note that if the user profile running MySQL has sufficient authority dropping a MySQL schema will drop a DB2 schema of the same name even if the schema never contained any `IBMDB2I' tables and contains objects not related to MySQL. Therefore, it is recommended that extreme caution be used when dropping MySQL schemas when the `IBMDB2I' plugin is installed.  File: manual.info, Node: se-db2-creating-tables-identifiers, Next: se-db2-creating-tables-indexnames, Prev: se-db2-creating-tables, Up: se-db2-creating-tables 14.7.3.1 Identifier names ......................... DB2 for i file objects have both a short (10-character) system name and an SQL name. The DB2 for i SQL name is always the same as the MySQL name. However, because MySQL's sensitivity to the lettercase of schema and table names depends on the file system containing the datadir, mapping the MySQL name to the system name of the corresponding DB2 for i object must account for several factors, described below. When MySQL is operating in a case-sensitive mode (that is, datadir is in a case-sensitive file-system like (/QOpenSys), the case of the system name of the `IBMDB2I' object reflects the case of the name specified to MySQL. If the object has all uppercase characters and is equal to or less than 10 characters in length, the system name will be undelimited and in uppercase.If the object name has mixed or lower-case letters, the IBM i system name will contain up to 8 characters of the name in the specified case and will be delimited by surrounding quotation marks. If the MySQL name has more characters than can fit in the delimited system name, the system name will be generated as a mangled name delimited by surrounding quotation marks. Examples of this naming behavior are given below: *Naming Behavior in DB2 Storage Engine* MySQL name DB2 for i SQL name IBM i System name mytable mytable "mytable" mylongertable mylongertable "mylo0001" UPPERTABLE UPPERTABLE UPPERTABLE UPPERLONGTABLE UPPERLONGTABLE UPPER00001 MixedTab MixedTab "MixedTab" MixedlongerTab MixedlongerTab "Mixe0001" If MySQL is operating in a case-insensitive mode, the IBM i system name will contain up to 8 characters of the name in lower case and will be delimited by surrounding quotation marks. If the MySQL name has more characters than can fit in the delimited system name, the system name will be generated as a mangled name delimited by surrounding quotation marks. Note that IBM i system names are not changed when a RENAME TABLE command is executed. Only the DB2 for i SQL name changes.  File: manual.info, Node: se-db2-creating-tables-indexnames, Prev: se-db2-creating-tables-identifiers, Up: se-db2-creating-tables 14.7.3.2 Index names .................... * Menu: * se-db2-data-type-mapping:: Data type mapping Unlike MySQL, DB2 for i requires that index names be unique to an entire schema. To support MySQL indexes, `IBMDB2I' creates the DB2 for i indexes with modified file names. The generated name is a concatenation of the index name, three underscores (_), and the table name. For example, `CREATE INDEX idx1 ON tab1 (a, b)' would create a DB2 index named `idx___tab1'. If the ibmdb2i_create_index_option value is set to 1, an additional index may be created which is named with an additional `H_' marker between the index and table names (for example, idx___H_tab1). These generated names are then mangled to create the an IBM i system name, as described above. If a table is renamed, the indexes will also be renamed. This index name generation scheme also has implications for the length of index and table names; to permit the generated name and allow for delimiting quotation marks, the combined length of the index and table names must be less than or equal to 121 characters.  File: manual.info, Node: se-db2-data-type-mapping, Prev: se-db2-creating-tables-indexnames, Up: se-db2-creating-tables-indexnames 14.7.3.3 Data type mapping .......................... When creating a table, `IBMDB2I' may map the MySQL types specified on a `CREATE TABLE' statement into a corresponding or compatible DB2 for i type. Examples include the `BIT' type, which is stored as a `BINARY' field, or the `MEDIUMINT' type, which is stored as an `INTEGER' field. For most data types, this mapping is transparent. Data types which have restrictions unique to `IBMDB2I' are documented in *Note se-db2-notes::.  File: manual.info, Node: se-db2-metadata, Next: se-db2-transactions, Prev: se-db2-creating-tables, Up: se-db2 14.7.4 Database/metadata management ----------------------------------- When an `IBMDB2I' table is created, a File Level ID (FID) file is created in the database directory. This file has an extension .FID and contains the last known FID of the associated DB2 for i physical file. The `IBMDB2I' engine uses this FID value to determine whether incompatible changes have been made to the table by an external (non-MySQL) interface. If the physical file is altered, DB2 for i automatically generates a new FID. The next time `IBMDB2I' attempts to access the file, it will detect that the new FID does not match the known FID, and it will prevent MySQL from using the table. In some cases, the changes to the physical file that cause the FID to be updated may not adversely affect access through MySQL and `IBMDB2I'. In this case, a user may wish to override the FID check that `IBMDB2I' performs. A user with appropriate permissions may do so simply by deleting the `.FID' file associated with the table and performing a `FLUSH TABLE' statement against the table. `IBMDB2I' will then regenerate the file with the new FID the next time the table is accessed from MySQL. If triggers or constraints are applied to the table from a native DB2 interface, they will be respected when accessing the table from MySQL, but MySQL will have no knowledge of the triggers or constraints. Likewise, views and indexes can be created over the tables from a DB2 interface, but the indexes will not be accessible from MySQL.  File: manual.info, Node: se-db2-transactions, Next: se-db2-terms, Prev: se-db2-metadata, Up: se-db2 14.7.5 Transaction behavior --------------------------- The `IBMDB2I' storage engine supports row-level transaction management. All MySQL isolation levels are supported by the engine, and where highest performance is required, transaction support can be disabled globally or per session by modifying the ibmdb2i_transaction_unsafe configuration option. `IBMDB2I' uses the underlying DB2 for i transaction support to implement MySQL isolation levels. DB2 for i uses table and row locks to implement the various isolation levels, as described below: *`IBMDB2I' Isolation Levels* Isolation Read-only Read-write level (SELECT) (UPDATE, DELETE) Lock enforcement Visibility of Lock Visibility of uncommitted enforcement uncommitted work on behalf work on behalf of other of other connections connections SERIALIZABLETable is locked N/A Table is N/A until end of locked until transaction.Other end of connections may transaction.Other read rows while connections locked. may read rows while locked. REPEATABLE Rows that have Rows cannot be Rows that have Rows cannot be READ been read are read until been read are read until locked until work is locked until work is end of committed. end of committed. transaction.Other transaction.Other connections may connections read and insert may read and rows while insert rows locked. while locked. READ Row is locked Rows cannot be Row is locked Rows cannot be COMMITTED while cursor is read until while cursor read until positioned on work is is positioned work is that row.Other committed. on that committed. connections may row.Other read and insert connections rows while may read and locked. insert rows while locked. READ Row is locked Rows can be Row is locked Rows can be UNCOMMITTED while cursor is read before while cursor read before positioned on work is is positioned work is that row.Other committed. on that committed. connections may row.Other read and insert connections rows while may read and locked. insert rows while locked. transaction_unsafeNo locks Full access Table is Unrestricted locked until access end of transaction.Other connections may read rows while locked. Attempts to access locked rows time out according to the timeout value associated with the underlying DB2 physical file. This timeout wait is 30 seconds by default. Refer to http://publib.boulder.ibm.com/infocenter/iseries/v5r4/index.jsp?topic=/dbp/rbafoconcrec.htm (http://publib.boulder.ibm.com/infocenter/iseries/v5r4/index.jsp?topic=/dbp/rbafoconcrec.htm) for more information. Because `IBMDB2I' does not multi-version rows under commitment control, row lock contention may occur under certain scenarios. In particular, when multiple connections attempt to read overlapping ranges of rows while performing a statement that does updates, the connections may contend for the same row locks. This may lead to delays until the row lock timeout expires. Creating appropriate indexes and increasing query selectivity to reduce range overlap may help to alleviate this contention.  File: manual.info, Node: se-db2-terms, Next: se-db2-notes, Prev: se-db2-transactions, Up: se-db2 14.7.6 Principles and Terminology --------------------------------- `AUTO_INCREMENT' The MySQL auto_increment column attribute can be used to generate a unique identity for new rows.The `IBMDB2I' storage engine maps the MySQL auto_increment attribute to the DB2 for i identity attribute For most MySQL storage engines, the auto_increment value is determined by adding one to the maximum value stored in the table for the column.For the `IBMDB2I' storage engine, DB2 for i generates the identity value by adding one to the last generated value. Following are some example MySQL statements to illustrate the point. create table t1 (a int auto increment, primary key(a)) engine = ibmdb2i; insert into t1 values(3); insert into t1 values(null),(null); For the first INSERT statement, an explicit value of 3 is specified for the auto_increment column, so the value 3 is stored in the inserted row.For the second INSERT statement null is specified, so generated values 1 and 2 will be stored in the rows. Duplicate key failures can occur in DB2 for i if a MySQL application mixes explicit auto_increment values with generated values within a table. For the example above, if one more record is inserted into the table for which an auto_increment value is generated, a duplicate key error will occur because the value 3 (that is, the last generated value plus one) already exists in the table.To effect the MySQL behavior for auto_increment columns, the `IBMDB2I' storage engine will detect a duplicate key error, alter the restart value for the DB2 identity column to the maximum value plus one, and retry the failed insert, but only if the following conditions are true: * The duplicate key error occurred on an index for which the auto_increment column is a key field * An exclusive (LENR) lock can be acquired on the table * The error occurred on the first or only row of the `INSERT' statement. The `IBMDB2I' storage engine does not support the following usage of auto_increment columns: 1. Any MySQL global or session variable that affects the start, increment, or offset for generated auto_increment values. 2. Any MySQL feature that returns the _next value to be used_ for an auto_increment column. 3. An auto_increment column on a MySQL partitioned table.  File: manual.info, Node: se-db2-notes, Next: se-db2-collations, Prev: se-db2-terms, Up: se-db2 14.7.7 Notes and Limitations ---------------------------- * When using multiples instances of MySQL on a single i5 host you should be aware that the two independent instances will access the same database within the DB2 environment. This can lead to namespace collisions and issues. To get round this limitation, you should configure different IBM i independent auxilliary storage pools (ISAPs) for each MySQL server, and then use the `ibmdb2i_rdb_name' option to MySQL to configure which IASP should be used for each MySQL instance. * Indexes over `VARBINARY' columns may not provide accurate estimates the optimizer. Queries over such indexes may produce error 2027 in the error log but will succeed. This affects only the performance of these queries, not the correctness of the results. * Setting `ibmdb2i_system_trace_level = 16 (STRTRC)' may cause unpredictable failures including error 2088 on some operations. This is unlikely to affect any users, as this value is recommended only for serviceability purposes. * `IBMDB2I' honors the `CASCADE'/`RESTRICT' option on the `DROP TABLE' statement. * The use of `FLUSH TABLES WITH READ LOCK' is discouraged when using `IBMDB2I' tables. Due to differences in internal locking implementations, `FLUSH TABLES WITH READ LOCK' may produce deadlocks on `IBMDB2I' tables. * Row-based replication is supported by `IBMDB2I'. Statement-based replication is not supported. * Schema name lengths are limited to 10 characters in IBM i 5.4 and 30 characters in IBM i 6.1. If the schema name is mixed- or lower-case, two characters must be subtracted from the limit to account for surrounding quotation marks. * The RENAME TABLE command cannot be used to move `IBMDB2I' tables from one database to another. * The maximum length of the internal row format for `IBMDB2I' is 32767 bytes. Because the internal row format may differ from the MySQL row format due to data mapping differences (see Creating schemas and tables section), anticipating this limit may be difficult. * The combined length of the index and table names must be less than or equal to 121 characters. * Indexes over TEXT or BLOB columns with a maximum length greater than 255 characters are not supported. The ibmdb2i_map_blob_to_varchar option can be used to work around this limitation for TEXT fields up to 64K characters. * Specific restrictions apply to certain data types as described in the following chart: *Data Type Restrictions in `IBMDB2I'* MySQL data Restriction type `LONGBLOB' The maximum length of a DB2 BLOB data type is 2GB. or `LONGTEXT' `DATE' `IBMDB2I' does not support the special date value of '0000-00-00'. The restrictions on `DATE' and `DATETIME' columns can be removed by setting the value of `ibmdb2i_compat_opt_allow_zero_date_vals' to 1. `DATETIME' `IBMDB2I' does not support the special datetime value of '0000-00-00 00:00:00'. The restrictions on `DATE' and `DATETIME' columns can be removed by setting the value of `ibmdb2i_compat_opt_allow_zero_date_vals' to 1. `DECIMAL(p, If p is greater than 63 and s is greater than (p-63), s)' or the field definition is truncated to `DECIMAL(63, `NUMERIC(p, s-(p-63))'. If p is greater than 63 and s is less s)' than or equal to (p-63), the definition is not supported. `TIME' By default, `IBMDB2I' only supports times in the range '00:00:00' to '23:59:59.' See the ibmdb2i_create_time_columns_as_tod option for more information. * These MySQL statements are not supported by the `IBMDB2I' Engine: * `CACHE INDEX' and `LOAD INDEX INTO CACHE' * `HANDLER' * `CHECK TABLE' * `REPAIR TABLE' * ` BACKUP-RESTORE TABLE' * The `ucs2_spanish2_ci' and `utf8_spanish2_ci' collations are not supported by `IBMDB2I'. There are no plans to support these collations. * The `ucs2_swedish_ci' and `utf8_swedish_ci' collations were added in MySQL 5.1.35. supported by `IBMDB2I'. As with other language-specific unicode collations, the support will be only be available on IBM i 6.1 and later releases.  File: manual.info, Node: se-db2-collations, Next: se-db2-errors, Prev: se-db2-notes, Up: se-db2 14.7.8 Character sets and collations ------------------------------------ DB2 for i only supports a single collation per index or foreign key constraint. A foreign key constraint must have the same collation as a primary key constraint, if one exists.. Character sets and collations supported by `IBMDB2I' are described in the list below. IBM i 6.1 is required for the most comprehensive collation support. Note that Chinese, Japanese, and Korean character sets are converted to UTF-16 for storage in DB2 for i; `utf8_general_ci' is converted to `UCS2' for storage in DB2 for i. *Collation Compatibility in `IBMDB2I' and MySQL* MySQL SupportedSupported Collation in IBM in IBM i 5.4 i 6.1 `armscii8_general_ci' `armscii8_bin' `ascii_general_ci' Yes `ascii_bin' Yes `big5_chinese_ci'Yes Yes `big5_bin' Yes Yes `cp1250_croatian_ci' Yes `cp1250_czech_cs' Yes `cp1250_general_ci' Yes `cp1250_polish_ci' Yes `cp1250_bin' Yes `cp1251_bulgarian_ci' Yes `cp1251_general_ci' Yes `cp1251_general_cs' Yes `cp1251_ukrainian_ci' `cp1251_bin' Yes `cp1256_general_ci' Yes `cp1256_bin' Yes `cp1257_general_ci' `cp1257_lithuanian_ci' `cp1257_bin' `cp850_general_ci'Yes Yes `cp850_bin' Yes Yes `cp852_general_ci' Yes `cp852_bin' Yes `cp866_general_ci' `cp866_bin' `cp932_japanese_ci'Yes Yes `cp932_bin' Yes Yes `dec8_swedish_ci' `dec8_bin' `eucjpms_japanese_ci' `eucjpms_bin' `euckr_korean_ci'Yes Yes `euckr_bin' Yes Yes `gb2312_chinese_ci'Yes Yes `gb2312_bin' Yes Yes `gbk_chinese_ci'Yes Yes `gbk_bin' Yes Yes `geostd8_general_ci' `geostd8_bin' `greek_general_ci'Yes Yes `greek_bin' Yes Yes `hebrew_general_ci'Yes Yes `hebrew_bin' Yes Yes `hp8_english_ci' `hp8_bin' `keybcs2_general_ci' `keybcs2_bin' `koi8r_general_ci' `koi8r_bin' `koi8u_general_ci' `koi8u_bin' `latin1_danish_ci'Yes Yes `latin1_general_ci'Yes Yes `latin1_general_cs'Yes Yes `latin1_german1_ci'Yes Yes `latin1_german2_ci' `latin1_spanish_ci'Yes Yes `latin1_swedish_ci'Yes Yes `latin1_bin' Yes Yes `latin2_croatian_ci'Yes Yes `latin2_czech_cs'Yes Yes `latin2_general_ci'Yes Yes `latin2_hungarian_ci'Yes Yes `latin2_bin' Yes Yes `latin5_turkish_ci'Yes Yes `latin5_bin' Yes Yes `latin7_estonian_cs' `latin7_general_ci' `latin7_general_cs' `latin7_bin' `macce_general_ci' Yes `macce_bin' Yes `macroman_general_ci' `macroman_bin' `sjis_japanese_ci'Yes Yes `sjis_bin' Yes Yes `swe7_swedish_ci' `swe7_bin' `tis620_thai_ci'Yes Yes `tis620_bin' Yes Yes `ucs2_czech_ci' Yes `ucs2_danish_ci' Yes `ucs2_esperanto_ci' Yes `ucs2_estonian_ci' Yes `ucs2_general_ci'Yes Yes `ucs2_hungarian_ci' Yes `ucs2_icelandic_ci' Yes `ucs2_latvian_ci' Yes `ucs2_lithuanian_ci' Yes `ucs2_persian_ci' Yes `ucs2_polish_ci' Yes `ucs2_roman_ci' `ucs2_romanian_ci' Yes `ucs2_slovak_ci' Yes `ucs2_slovenian_ci' Yes `ucs2_spanish_ci' Yes `ucs2_spanish2_ci' Yes `ucs2_turkish_ci' Yes `ucs2_unicode_ci'Yes Yes `ucs2_bin' Yes Yes `ujis_japanese_ci'Yes Yes `ujis_bin' Yes Yes `utf8_czech_ci' Yes `utf8_danish_ci' Yes `utf8_esperanto_ci' Yes `utf8_estonian_ci' Yes `utf8_general_ci'Yes Yes `utf8_hungarian_ci' Yes `utf8_icelandic_ci' Yes `utf8_latvian_ci' Yes `utf8_lithuanian_ci' Yes `utf8_persian_ci' Yes `utf8_polish_ci' Yes `utf8_roman_ci' `utf8_romanian_ci' Yes `utf8_slovak_ci' Yes `utf8_slovenian_ci' Yes `utf8_spanish_ci' Yes `utf8_spanish2_ci' Yes `utf8_turkish_ci' Yes `utf8_unicode_ci' Yes `utf8_bin' Yes Yes  File: manual.info, Node: se-db2-errors, Prev: se-db2-collations, Up: se-db2 14.7.9 Error codes and trouble-shooting information --------------------------------------------------- Errors reported by the `IBMDB2I' engine may originate from two locations. Error values under 2500 originate in DB2 for i. Error values over 2500 originate in the storage engine itself. Occasionally, errors are reported by `IBMDB2I' but, due to the architecture of MySQL, cannot be directly exposed to MySQL client interfaces. In these cases, issuing a `SHOW ERRORS' statement or referring to the MySQL error log may be necessary to determine the cause of a failure. Errors which originate in DB2 for i are usually encountered in the DB2 for i SQL Server Mode job (QSQSRVR) which services the MySQL client connection; additional information about failures can often be found by looking in the job log of the associated QSQSRVR job. Following is the list of codes and messages for errors that occur in DB2 for i that are reported by the `IBMDB2I' engine. %d and %s represent numbers and strings, respectively, that are replaced when the message is displayed. *Error Codes from `IBMDB2I'* Error Error Message Text Code Number 0 Successful 2016 Thread ID is too long 2017 Error creating a SPACE memory object 2018 Error creating a FILE memory object 2019 Error creating a SPACE synchronization token 2020 Error creating a FILE synchronization token 2021 See message %-.7s in joblog for job %-.6s/%-.10s/%-.10s. 2022 Error unlocking a synchronization token when closing a connection 2023 Invalid action specified for an 'object lock' request 2024 Invalid action specified for a savepoint request 2025 Partial keys are not supported with an ICU sort sequence 2026 Error retrieving an ICU sort key 2027 Error converting single-byte sort sequence to UCS-2 2028 An unsupported collation was specified 2029 Validation failed for referenced table of foreign key constraint 2030 Error extracting table for constraint information 2031 Error extracting referenced table for constraint information 2032 Invalid action specified for a 'commitment control' request 2033 Invalid commitment control isolation level specified on 'open' request 2034 Invalid file handle 2036 Invalid option specified for returning data on 'read' request 2037 Invalid orientation specified for 'read' request 2038 Invalid option type specified for 'read' request 2039 Invalid isolation level for starting commitment control 2040 Error unlocking a synchronization token in module QMYALC 2041 Length of space for returned format is not long enough 2042 SQL XA transactions are currently unsupported by this interface 2043 The associated QSQSRVR job was killed or ended unexpectedly. 2044 Error unlocking a synchronization token in module QMYSEI 2045 Error unlocking a synchronization token in module QMYSPO 2046 Error converting input CCSID from short form to long form 2048 Error getting associated CCSID for CCSID conversion 2049 Error converting a string from one CCSID to another 2050 Error unlocking a synchronization token 2051 Error destroying a synchronization token 2052 Error locking a synchronization token 2053 Error recreating a synchronization token 2054 A space handle was not specified for a constraint request 2055 An SQL cursor was specified for a delete request 2057 Error on delete request because current UFCB for connection is not open 2058 An SQL cursor was specified for an object initialization request 2059 An SQL cursor was specified for an object override request 2060 A space handle was not specified for an object override request 2061 An SQL cursor was specified for an information request 2062 An SQL cursor was specified for an object lock request 2063 An SQL cursor was specified for an optimize request 2064 A data handle was not specified for a read request 2065 A row number handle was not specified for a read request 2066 A key handle was not specified for a read request 2067 An SQL cursor was specified for an row estimation request 2068 A space handle was not specified for a row estimation request 2069 An SQL cursor was specified for a release record request 2070 A statement handle was not specified for an 'execute immediate' request 2071 A statement handle was not specified for a 'prepare open' request 2072 An SQL cursor was specified for an update request 2073 The UFCB was not open for read 2074 Error on update request because current UFCB for connection is not open 2075 A data handle was not specified for an update request 2076 An SQL cursor was specified for a write request 2077 A data handle was not specified for a write request 2078 An unknown function was specified on a process request 2079 A share definition was not specified for an 'allocate share' request 2080 A share handle was not specified for an 'allocate share' request 2081 A use count handle was not specified for an 'allocate share' request 2082 A 'records per key' handle was not specified for an information request 2083 Error resolving LOB address 2084 Length of a LOB space is too small 2085 An unknown function was specified for a server request 2086 Object authorization failed. See message %-.7s in joblog for job %-.6s/%-.10s/%-.10s. for more information. 2088 Error locking mutex on server 2089 Error unlocking mutex on server 2090 Error checking for RDB name in RDB Directory 2091 Error creating mutex on server 2094 Error unlocking mutex 2095 Error connecting to server job 2096 Error connecting to server job 2098 Function check occurred while registering parameter spaces. See job log. 2101 End of block 2102 The file has changed and might not be compatible with the MySQL table definition 2103 Error giving pipe to server job 2104 There are open object locks when attempting to deallocate 2105 There is no open lock 2108 The maximum value for the auto_increment data type was exceeded 2109 Error occurred closing the pipe 2110 Error occurred taking a descriptor for the pipe 2111 Error writing to pipe 2112 Server was interrupted 2113 No pipe descriptor exists for reuse 2114 Error occurred during an SQL prepare statement 2115 Error occurred during an SQL open 2122 An unspecified error was returned from the system. Following is the list of error codes and messages that occur within the `IBMDB2I' storage engine. *Error Codes and Messages in `IBMDB2I'* Error Error Message Text Code Number 2501 Error opening codeset conversion from %.64s to %.64s (errno = %d). * Resolution:* Alter the table definition to specify a character set that is supported by the `IBMDB2I' engine. 2502 Invalid %-.10s name '%-.128s. * Resolution:* If a field name, ensure that it is less than the maximum length of 126 characters.If an index name, ensure that the length of the index name plus the length of the table name is less than 121 characters. 2503 Unsupported move from '%-.128s' to '%-.128s' on RENAME TABLE statement. * Resolution:* Moving a table from one schema to another is not supported by the `IBMDB2I' engine. Create a new table in the 'to' schema, copy the data to the new table, and then drop the old table. 2504 The %-.64s character set is not supported. * Resolution:* Try using another character set. 2505 Auto_increment is not allowed for a partitioned table. * Resolution:* Remove the auto_increment attribute from the table or do not partition the table. 2506 Character set conversion error due to unknown encoding scheme %d. * Resolution:* Alter the table definition to ensure that character sets assigned to columns are supported by the `IBMDB2I' engine. 2508 Table '%-.128s' was not found by the storage engine. * Resolution:* A table definition exists in MySQL, but the correspondingtable in DB2 for i is not found. Delete the MySQL table or restore the DB2 table. 2509 Could not resolve to %-.128s in library %-.10s type %-.10s (errno = %d). * Resolution:* Restore the missing IBM i object to the system. 2510 Error on _PGMCALL for program %-.10s in library %-.10s (error = %d). * Resolution:* This is an internal error. 2511 Error on _ILECALL for API '%.128s' (error = %d). *Resolution:* This is an internal error. 2512 Error in iconv() function during character set conversion (errno = %d). *Resolution:* Ensure the text being inserted contains only valid code points for the associated character set. This may be caused by using ENCRYPT or COMPRESS on a text field, resulting in binary data containing invalid characters. 2513 Error from Get Encoding Scheme (QTQGESP) API: %d, %d, %d *Resolution:* This is an internal error. 2514 Error from Get Related Default CCSID (QTQGRDC) API: %d, %d, %d. * Resolution:* This is an internal error. 2515 Data out of range for column '%.192s'. * Resolution:* DB2 for i does not support a zero value for DATE and DATETIME data types. Specify a new value for the column. 2516 Schema name '%.128s' exceeds maximum length of %d characters. * Resolution:* Change the schema name so that its length does not exceed the maximum. For mixed case or lowercase names, permit 2 characters for outer quotation marks. 2517 Multiple collations not supported in a single index. * Resolution:* DB2 for i only supports sort sequences at the table or index level, so all character-based columns in the primary key or index must be using the same collation. Alter the table definition so that all columns use the same collation. 2518 Sort sequence was not found. * Resolution:* Alter the table to use a collation that is supported by the `IBMDB2I' engine. 2519 One or more characters in column %.128s were substituted during conversion. * Resolution:* This is a warning that during the conversion of data from MySQL to DB2 some characters were replaced with substitute characters. 2520 A decimal column exceeded the maximum precision. Data may be truncated. * Resolution:* A decimal column specified on a CREATE TABLE or ALTER TABLE command has greater precision than DB2 permits. Data stored in this column may be truncated. Change the column specification to have a precision less than or equal to 63. 2521 Some data returned by DB2 for table %s could not be converted for MySQL. * Resolution:* This is a warning that some data could not be converted from DB2 to MySQL. Data was likely inserted into the table using DB2 interfaces that is valid data for DB2 but is invalid for MySQL. 2523 Column %.128s contains characters that cannot be converted. * Resolution:* An error occurred converting data from the MySQL character set to the associated DB2 coded character set identifier (CCSID).Omit the incompatible characters or alter the table to specify a different character set for the column. 2524 An invalid name was specified for ibmdb2i_rdb_name. * Resolution:* Specify a valid relational database (RDB) name. 2525 A duplicate key was encountered for index '%.128s'. *Resolution:* : Specify a unique key value for the row. Generally, this error occurs if a unique constraint or index has been applied to the table from a non-MySQL interface. 2528 Some attribute(s) defined for column '%.128s' may not be honored by accesses from DB2.  File: manual.info, Node: merge-storage-engine, Next: memory-storage-engine, Prev: se-db2, Up: storage-engines 14.8 The `MERGE' Storage Engine =============================== * Menu: * merge-table-advantages:: `MERGE' Table Advantages and Disadvantages * merge-table-problems:: `MERGE' Table Problems The `MERGE' storage engine, also known as the `MRG_MyISAM' engine, is a collection of identical `MyISAM' tables that can be used as one. `Identical' means that all tables have identical column and index information. You cannot merge `MyISAM' tables in which the columns are listed in a different order, do not have exactly the same columns, or have the indexes in different order. However, any or all of the `MyISAM' tables can be compressed with *Note `myisampack': myisampack. See *Note myisampack::. Differences in table options such as `AVG_ROW_LENGTH', `MAX_ROWS', or `PACK_KEYS' do not matter. An alternative to a `MERGE' table is a partitioned table, which stores partitions of a single table in separate files. Partitioning enables some operations to be performed more efficiently and is not limited to the `MyISAM' storage engine. For more information, see *Note partitioning::. When you create a `MERGE' table, MySQL creates two files on disk. The files have names that begin with the table name and have an extension to indicate the file type. An `.frm' file stores the table format, and an `.MRG' file contains the names of the underlying `MyISAM' tables that should be used as one. The tables do not have to be in the same database as the `MERGE' table. You can use *Note `SELECT': select, *Note `DELETE': delete, *Note `UPDATE': update, and *Note `INSERT': insert. on `MERGE' tables. You must have `SELECT', `DELETE', and `UPDATE' privileges on the `MyISAM' tables that you map to a `MERGE' table. *Note*: The use of `MERGE' tables entails the following security issue: If a user has access to `MyISAM' table T, that user can create a `MERGE' table M that accesses T. However, if the user's privileges on T are subsequently revoked, the user can continue to access T by doing so through M. Use of *Note `DROP TABLE': drop-table. with a `MERGE' table drops only the `MERGE' specification. The underlying tables are not affected. To create a `MERGE' table, you must specify a `UNION=(LIST-OF-TABLES)' option that indicates which `MyISAM' tables to use. You can optionally specify an `INSERT_METHOD' option to control how inserts into the `MERGE' table take place. Use a value of `FIRST' or `LAST' to cause inserts to be made in the first or last underlying table, respectively. If you specify no `INSERT_METHOD' option or if you specify it with a value of `NO', inserts into the `MERGE' table are not permitted and attempts to do so result in an error. The following example shows how to create a `MERGE' table: mysql> CREATE TABLE t1 ( -> a INT NOT NULL AUTO_INCREMENT PRIMARY KEY, -> message CHAR(20)) ENGINE=MyISAM; mysql> CREATE TABLE t2 ( -> a INT NOT NULL AUTO_INCREMENT PRIMARY KEY, -> message CHAR(20)) ENGINE=MyISAM; mysql> INSERT INTO t1 (message) VALUES ('Testing'),('table'),('t1'); mysql> INSERT INTO t2 (message) VALUES ('Testing'),('table'),('t2'); mysql> CREATE TABLE total ( -> a INT NOT NULL AUTO_INCREMENT, -> message CHAR(20), INDEX(a)) -> ENGINE=MERGE UNION=(t1,t2) INSERT_METHOD=LAST; Note that column `a' is indexed as a `PRIMARY KEY' in the underlying `MyISAM' tables, but not in the `MERGE' table. There it is indexed but not as a `PRIMARY KEY' because a `MERGE' table cannot enforce uniqueness over the set of underlying tables. (Similarly, a column with a `UNIQUE' index in the underlying tables should be indexed in the `MERGE' table but not as a `UNIQUE' index.) After creating the `MERGE' table, you can use it to issue queries that operate on the group of tables as a whole: mysql> SELECT * FROM total; +---+---------+ | a | message | +---+---------+ | 1 | Testing | | 2 | table | | 3 | t1 | | 1 | Testing | | 2 | table | | 3 | t2 | +---+---------+ To remap a `MERGE' table to a different collection of `MyISAM' tables, you can use one of the following methods: * `DROP' the `MERGE' table and re-create it. * Use `ALTER TABLE TBL_NAME UNION=(...)' to change the list of underlying tables. Beginning with MySQL 5.1.24, it is also possible to use `ALTER TABLE ... UNION=()' (that is, with an empty *Note `UNION': union. clause) to remove all of the underlying tables. As of MySQL 5.1.15, the underlying table definitions and indexes must conform more closely than previously to the definition of the `MERGE' table. Conformance is checked when a table that is part of a `MERGE' table is opened, not when the `MERGE' table is created. If any table fails the conformance checks, the operation that triggered the opening of the table fails. This means that changes to the definitions of tables within a `MERGE' may cause a failure when the `MERGE' table is accessed. The conformance checks applied to each table are: * The underlying table and the `MERGE' table must have the same number of columns. * The column order in the underlying table and the `MERGE' table must match. * Additionally, the specification for each corresponding column in the parent `MERGE' table and the underlying tables are compared and must satisfy these checks: * The column type in the underlying table and the `MERGE' table must be equal. * The column length in the underlying table and the `MERGE' table must be equal. * The column of the underlying table and the `MERGE' table can be `NULL'. * The underlying table must have at least as many indexes as the `MERGE' table. The underlying table may have more indexes than the `MERGE' table, but cannot have fewer. *Note*: A known issue exists where indexes on the same columns must be in identical order, in both the `MERGE' table and the underlying `MyISAM' table. See Bug#33653. Each index must satisfy these checks: * The index type of the underlying table and the `MERGE' table must be the same. * The number of index parts (that is, multiple columns within a compound index) in the index definition for the underlying table and the `MERGE' table must be the same. * For each index part: * Index part lengths must be equal. * Index part types must be equal. * Index part languages must be equal. * Check whether index parts can be `NULL'. For information about the table checks applied prior to MySQL 5.1.15, see *Note merge-table-problems::. As of MySQL 5.1.20, if a `MERGE' table cannot be opened or used because of a problem with an underlying table, *Note `CHECK TABLE': check-table. displays information about which table caused the problem. * Additional Resources * * A forum dedicated to the `MERGE' storage engine is available at `http://forums.mysql.com/list.php?93'.  File: manual.info, Node: merge-table-advantages, Next: merge-table-problems, Prev: merge-storage-engine, Up: merge-storage-engine 14.8.1 `MERGE' Table Advantages and Disadvantages ------------------------------------------------- `MERGE' tables can help you solve the following problems: * Easily manage a set of log tables. For example, you can put data from different months into separate tables, compress some of them with *Note `myisampack': myisampack, and then create a `MERGE' table to use them as one. * Obtain more speed. You can split a large read-only table based on some criteria, and then put individual tables on different disks. A `MERGE' table structured this way could be much faster than using a single large table. * Perform more efficient searches. If you know exactly what you are looking for, you can search in just one of the underlying tables for some queries and use a `MERGE' table for others. You can even have many different `MERGE' tables that use overlapping sets of tables. * Perform more efficient repairs. It is easier to repair individual smaller tables that are mapped to a `MERGE' table than to repair a single large table. * Instantly map many tables as one. A `MERGE' table need not maintain an index of its own because it uses the indexes of the individual tables. As a result, `MERGE' table collections are _very_ fast to create or remap. (You must still specify the index definitions when you create a `MERGE' table, even though no indexes are created.) * If you have a set of tables from which you create a large table on demand, you can instead create a `MERGE' table from them on demand. This is much faster and saves a lot of disk space. * Exceed the file size limit for the operating system. Each `MyISAM' table is bound by this limit, but a collection of `MyISAM' tables is not. * You can create an alias or synonym for a `MyISAM' table by defining a `MERGE' table that maps to that single table. There should be no really notable performance impact from doing this (only a couple of indirect calls and `memcpy()' calls for each read). The disadvantages of `MERGE' tables are: * You can use only identical `MyISAM' tables for a `MERGE' table. * Some `MyISAM' features are unavailable in `MERGE' tables. For example, you cannot create `FULLTEXT' indexes on `MERGE' tables. (You can create `FULLTEXT' indexes on the underlying `MyISAM' tables, but you cannot search the `MERGE' table with a full-text search.) * If the `MERGE' table is nontemporary, all underlying `MyISAM' tables must be nontemporary. If the `MERGE' table is temporary, the `MyISAM' tables can be any mix of temporary and nontemporary. * `MERGE' tables use more file descriptors than `MyISAM' tables. If 10 clients are using a `MERGE' table that maps to 10 tables, the server uses (10 x 10) + 10 file descriptors. (10 data file descriptors for each of the 10 clients, and 10 index file descriptors shared among the clients.) * Index reads are slower. When you read an index, the `MERGE' storage engine needs to issue a read on all underlying tables to check which one most closely matches a given index value. To read the next index value, the `MERGE' storage engine needs to search the read buffers to find the next value. Only when one index buffer is used up does the storage engine need to read the next index block. This makes `MERGE' indexes much slower on `eq_ref' searches, but not much slower on `ref' searches. For more information about `eq_ref' and `ref', see *Note explain::.  File: manual.info, Node: merge-table-problems, Prev: merge-table-advantages, Up: merge-storage-engine 14.8.2 `MERGE' Table Problems ----------------------------- The following are known problems with `MERGE' tables: * In versions of MySQL Server prior to 5.1.23 and 6.0.4, it was possible to create temporary merge tables with non-temporary child MyISAM tables. From versions 5.1.23 and 6.0.4, MERGE children were locked through the parent table. If the parent was temporary, it was not locked and so the children were not locked either. Parallel use of the MyISAM tables corrupted them. From 6.0.6 onwards, the children are locked independently from the parent. It is possible to have non-temporary children with a temporary parent. Even though the temporary MERGE table itself is not locked, each non-temporary child MyISAM table is locked anyway. The reintroduction of support for non-tempporary children with a temporary MERGE table was completed in 6.0.14. Note that 5.1.23 onwards does not currently have the child locking scheme required to support this. * If you use *Note `ALTER TABLE': alter-table. to change a `MERGE' table to another storage engine, the mapping to the underlying tables is lost. Instead, the rows from the underlying `MyISAM' tables are copied into the altered table, which then uses the specified storage engine. * The `INSERT_METHOD' table option for a `MERGE' table indicates which underlying `MyISAM' table to use for inserts into the `MERGE' table. However, use of the `AUTO_INCREMENT' table option for that `MyISAM' table has no effect for inserts into the `MERGE' table until at least one row has been inserted directly into the `MyISAM' table. * A `MERGE' table cannot maintain uniqueness constraints over the entire table. When you perform an *Note `INSERT': insert, the data goes into the first or last `MyISAM' table (as determined by the `INSERT_METHOD' option). MySQL ensures that unique key values remain unique within that `MyISAM' table, but not over all the underlying tables in the collection. * Because the `MERGE' engine cannot enforce uniqueness over the set of underlying tables, *Note `REPLACE': replace. does not work as expected. The two key facts are: * *Note `REPLACE': replace. can detect unique key violations only in the underlying table to which it is going to write (which is determined by the `INSERT_METHOD' option). This differs from violations in the `MERGE' table itself. * If *Note `REPLACE': replace. detects a unique key violation, it will change only the corresponding row in the underlying table it is writing to; that is, the first or last table, as determined by the `INSERT_METHOD' option. Similar considerations apply for *Note `INSERT ... ON DUPLICATE KEY UPDATE': insert-on-duplicate. * `MERGE' tables do not support partitioning. That is, you cannot partition a `MERGE' table, nor can any of a `MERGE' table's underlying `MyISAM' tables be partitioned. * You should not use *Note `ANALYZE TABLE': analyze-table, *Note `REPAIR TABLE': repair-table, *Note `OPTIMIZE TABLE': optimize-table, *Note `ALTER TABLE': alter-table, *Note `DROP TABLE': drop-table, *Note `DELETE': delete. without a `WHERE' clause, or *Note `TRUNCATE TABLE': truncate-table. on any of the tables that are mapped into an open `MERGE' table. If you do so, the `MERGE' table may still refer to the original table and yield unexpected results. To work around this problem, ensure that no `MERGE' tables remain open by issuing a *Note `FLUSH TABLES': flush. statement prior to performing any of the named operations. The unexpected results include the possibility that the operation on the `MERGE' table will report table corruption. If this occurs after one of the named operations on the underlying `MyISAM' tables, the corruption message is spurious. To deal with this, issue a *Note `FLUSH TABLES': flush. statement after modifying the `MyISAM' tables. * *Note `DROP TABLE': drop-table. on a table that is in use by a `MERGE' table does not work on Windows because the `MERGE' storage engine's table mapping is hidden from the upper layer of MySQL. Windows does not permit open files to be deleted, so you first must flush all `MERGE' tables (with *Note `FLUSH TABLES': flush.) or drop the `MERGE' table before dropping the table. * As of MySQL 5.1.15, the definition of the `MyISAM' tables and the `MERGE' table are checked when the tables are accessed (for example, as part of a *Note `SELECT': select. or *Note `INSERT': insert. statement). The checks ensure that the definitions of the tables and the parent `MERGE' table definition match by comparing column order, types, sizes and associated indexes. If there is a difference between the tables, an error is returned and the statement fails. Because these checks take place when the tables are opened, any changes to the definition of a single table, including column changes, column ordering, and engine alterations will cause the statement to fail. Prior to MySQL 5.1.15, table checks are applied as follows: * When you create or alter `MERGE' table, there is no check to ensure that the underlying tables are existing `MyISAM' tables and have identical structures. When the `MERGE' table is used, MySQL checks that the row length for all mapped tables is equal, but this is not foolproof. If you create a `MERGE' table from dissimilar `MyISAM' tables, you are very likely to run into strange problems. * Similarly, if you create a `MERGE' table from non-`MyISAM' tables, or if you drop an underlying table or alter it to be a non-`MyISAM' table, no error for the `MERGE' table occurs until later when you attempt to use it. * Because the underlying `MyISAM' tables need not exist when the `MERGE' table is created, you can create the tables in any order, as long as you do not use the `MERGE' table until all of its underlying tables are in place. Also, if you can ensure that a `MERGE' table will not be used during a given period, you can perform maintenance operations on the underlying tables, such as backing up or restoring them, altering them, or dropping and recreating them. It is not necessary to redefine the `MERGE' table temporarily to exclude the underlying tables while you are operating on them. * The order of indexes in the `MERGE' table and its underlying tables should be the same. If you use *Note `ALTER TABLE': alter-table. to add a `UNIQUE' index to a table used in a `MERGE' table, and then use *Note `ALTER TABLE': alter-table. to add a nonunique index on the `MERGE' table, the index ordering is different for the tables if there was already a nonunique index in the underlying table. (This happens because *Note `ALTER TABLE': alter-table. puts `UNIQUE' indexes before nonunique indexes to facilitate rapid detection of duplicate keys.) Consequently, queries on tables with such indexes may return unexpected results. * If you encounter an error message similar to `ERROR 1017 (HY000): Can't find file: 'TBL_NAME.MRG' (errno: 2)', it generally indicates that some of the underlying tables do not use the `MyISAM' storage engine. Confirm that all of these tables are `MyISAM'. * The maximum number of rows in a `MERGE' table is 2^64 (~1.844E+19; the same as for a `MyISAM' table), provided that the server was built using the `--with-big-tables' option. (All standard MySQL 5.1 standard binaries are built with this option; for more information, see *Note source-configuration-options::.) It is not possible to merge multiple `MyISAM' tables into a single `MERGE' table that would have more than this number of rows. * The `MERGE' storage engine does not support *Note `INSERT DELAYED': insert-delayed. statements. * Use of underlying `MyISAM' tables of differing row formats with a parent `MERGE' table is currently known to fail. See Bug#32364. * As of MySQL 5.1.23, you cannot change the union list of a nontemporary `MERGE' table when *Note `LOCK TABLES': lock-tables. is in effect. The following does _not_ work: CREATE TABLE m1 ... ENGINE=MRG_MYISAM ...; LOCK TABLES t1 WRITE, t2 WRITE, m1 WRITE; ALTER TABLE m1 ... UNION=(t1,t2) ...; However, you can do this with a temporary `MERGE' table. * As of MySQL 5.1.23, you cannot create a `MERGE' table with `CREATE ... SELECT', neither as a temporary `MERGE' table, nor as a nontemporary `MERGE' table. For example: CREATE TABLE m1 ... ENGINE=MRG_MYISAM ... SELECT ...; Attempts to do this result in an error: TBL_NAME is not `BASE TABLE'. * In some cases, differing `PACK_KEYS' table option values among the `MERGE' and underlying tables cause unexpected results if the underlying tables contain `CHAR' or `BINARY' columns. As a workaround, use `ALTER TABLE' to ensure that all involved tables have the same `PACK_KEYS' value. (Bug#50646)  File: manual.info, Node: memory-storage-engine, Next: example-storage-engine, Prev: merge-storage-engine, Up: storage-engines 14.9 The `MEMORY' Storage Engine ================================ The `MEMORY' storage engine creates tables with contents that are stored in memory. Formerly, these were known as `HEAP' tables. `MEMORY' is the preferred term, although `HEAP' remains supported for backward compatibility. *`MEMORY' Storage Engine Features* *Storage limits* RAM *Transactions* No *Locking Table granularity* *MVCC* No *Geospatial No *Geospatial No data type indexing support* support* *B-tree indexes* Yes *Hash indexes* Yes *Full-text No search indexes* *Clustered No *Data caches* N/A *Index caches* N/A indexes* *Compressed No *Encrypted data Yes *Cluster No data* Implemented in database the server (via support* encryption functions), rather than in the storage engine.* *Replication Yes *Foreign key No *Backup / Yes support support* point-in-time Implemented in recovery the server, Implemented in rather than in the server, the storage rather than in product.* the storage product.* *Query cache Yes *Update Yes support* statistics for data dictionary* `MEMORY' compared with MySQL Cluster Developers looking to deploy applications that use the *Note `MEMORY': memory-storage-engine. storage engine should consider whether MySQL Cluster is a better choice. A typical use case for the *Note `MEMORY': memory-storage-engine. engine involves these characteristics: * Operations such as session management or caching * In-memory storage for fast access and low latency * A read-only or read-mostly data access pattern (limited updates) However, *Note `MEMORY': memory-storage-engine. performance is constrained by contention resulting from single-thread execution and table lock overhead when processing updates. This limits scalability when load increases, particularly for statement mixes that include writes. Also, *Note `MEMORY': memory-storage-engine. does not preserve table contents across server restarts. MySQL Cluster offers the same features as the *Note `MEMORY': memory-storage-engine. engine with higher performance levels, and provides additional features not available with *Note `MEMORY': memory-storage-engine.: * Row-level locking and multiple-thread operation for low contention between clients * Scalability even with statement mixes that include writes * Optional disk-backed operation for data durability * Shared-nothing architecture and multiple-host operation with no single point of failure, enabling 99.999% availability * Automatic data distribution across nodes; application developers need not craft custom sharding or partitioning solutions * Support for variable-length data types (including *Note `BLOB': blob. and *Note `TEXT': blob.) not supported by *Note `MEMORY': memory-storage-engine. For a white paper with more detailed comparison of the *Note `MEMORY': memory-storage-engine. storage engine and MySQL Cluster, see Scaling Web Services with MySQL Cluster: An Alternative to the MySQL Memory Storage Engine (http://www.mysql.com/why-mysql/white-papers/mysql-wp_cluster-7.0_Cluster_MEMORY.php). This white paper includes a performance study of the two technologies and a step-by-step guide describing how existing *Note `MEMORY': memory-storage-engine. users can migrate to MySQL Cluster. The `MEMORY' storage engine associates each table with one disk file. The file name begins with the table name and has an extension of `.frm' to indicate that it stores the table definition. To specify that you want to create a `MEMORY' table, indicate that with an `ENGINE' table option: CREATE TABLE t (i INT) ENGINE = MEMORY; As indicated by the engine name, `MEMORY' tables are stored in memory. They use hash indexes by default, which makes them very fast, and very useful for creating temporary tables. However, when the server shuts down, all rows stored in `MEMORY' tables are lost. The tables themselves continue to exist because their definitions are stored in `.frm' files on disk, but they are empty when the server restarts. This example shows how you might create, use, and remove a `MEMORY' table: mysql> CREATE TABLE test ENGINE=MEMORY -> SELECT ip,SUM(downloads) AS down -> FROM log_table GROUP BY ip; mysql> SELECT COUNT(ip),AVG(down) FROM test; mysql> DROP TABLE test; `MEMORY' tables have the following characteristics: * Space for `MEMORY' tables is allocated in small blocks. Tables use 100% dynamic hashing for inserts. No overflow area or extra key space is needed. No extra space is needed for free lists. Deleted rows are put in a linked list and are reused when you insert new data into the table. `MEMORY' tables also have none of the problems commonly associated with deletes plus inserts in hashed tables. * `MEMORY' tables can have up to 64 indexes per table, 16 columns per index and a maximum key length of 3072 bytes. * The `MEMORY' storage engine supports both `HASH' and `BTREE' indexes. You can specify one or the other for a given index by adding a `USING' clause as shown here: CREATE TABLE lookup (id INT, INDEX USING HASH (id)) ENGINE = MEMORY; CREATE TABLE lookup (id INT, INDEX USING BTREE (id)) ENGINE = MEMORY; For general characteristics of B-tree and hash indexes, see *Note mysql-indexes::. * If a `MEMORY' table hash index has a high degree of key duplication (many index entries containing the same value), updates to the table that affect key values and all deletes are significantly slower. The degree of this slowdown is proportional to the degree of duplication (or, inversely proportional to the index cardinality). You can use a `BTREE' index to avoid this problem. * `MEMORY' tables can have nonunique keys. (This is an uncommon feature for implementations of hash indexes.) * Columns that are indexed can contain `NULL' values. * `MEMORY' tables use a fixed-length row-storage format. Variable-length types such as *Note `VARCHAR': char. are stored using a fixed length. * `MEMORY' tables cannot contain *Note `BLOB': blob. or *Note `TEXT': blob. columns. * `MEMORY' includes support for `AUTO_INCREMENT' columns. * `MEMORY' supports *Note `INSERT DELAYED': insert-delayed. See *Note insert-delayed::. * Non-`TEMPORARY' `MEMORY' tables are shared among all clients, just like any other non-`TEMPORARY' table. * `MEMORY' table contents are stored in memory, which is a property that `MEMORY' tables share with internal temporary tables that the server creates on the fly while processing queries. However, the two types of tables differ in that `MEMORY' tables are not subject to storage conversion, whereas internal temporary tables are: * `MEMORY' tables are never converted to disk tables. If an internal temporary table becomes too large, the server automatically converts it to on-disk storage, as described in *Note internal-temporary-tables::. * The maximum size of `MEMORY' tables is limited by the `max_heap_table_size' system variable, which has a default value of 16MB. To have larger (or smaller) `MEMORY' tables, you must change the value of this variable. The value in effect for *Note `CREATE TABLE': create-table. is the value used for the life of the table. (If you use *Note `ALTER TABLE': alter-table. or *Note `TRUNCATE TABLE': truncate-table, the value in effect at that time becomes the new maximum size for the table. A server restart also sets the maximum size of existing `MEMORY' tables to the global `max_heap_table_size' value.) You can set the size for individual tables as described later in this section. * The server needs sufficient memory to maintain all `MEMORY' tables that are in use at the same time. * Memory is not reclaimed if you delete individual rows from a `MEMORY' table. Memory is reclaimed only when the entire table is deleted. Memory that was previously used for rows that have been deleted will be re-used for new rows only within the same table. To free up the memory used by rows that have been deleted, use `ALTER TABLE ENGINE=MEMORY' to force a table rebuild. To free all the memory used by a `MEMORY' table when you no longer require its contents, you should execute *Note `DELETE': delete. or *Note `TRUNCATE TABLE': truncate-table. to remove all rows, or remove the table altogether using *Note `DROP TABLE': drop-table. * If you want to populate a `MEMORY' table when the MySQL server starts, you can use the `--init-file' option. For example, you can put statements such as *Note `INSERT INTO ... SELECT': insert-select. or *Note `LOAD DATA INFILE': load-data. into this file to load the table from a persistent data source. See *Note server-options::, and *Note load-data::. * A server's `MEMORY' tables become empty when it is shut down and restarted. However, if the server is a replication master, its slave are not aware that these tables have become empty, so they returns out-of-date content if you select data from these tables. To handle this, when a `MEMORY' table is used on a master for the first time since it was started, a *Note `DELETE': delete. statement is written to the master's binary log automatically, thus synchronizing the slave to the master again. Note that even with this strategy, the slave still has outdated data in the table during the interval between the master's restart and its first use of the table. However, if you use the `--init-file' option to populate the `MEMORY' table on the master at startup, it ensures that this time interval is zero. * The memory needed for one row in a `MEMORY' table is calculated using the following expression: SUM_OVER_ALL_BTREE_KEYS(MAX_LENGTH_OF_KEY + sizeof(char*) * 4) + SUM_OVER_ALL_HASH_KEYS(sizeof(char*) * 2) + ALIGN(LENGTH_OF_ROW+1, sizeof(char*)) `ALIGN()' represents a round-up factor to cause the row length to be an exact multiple of the `char' pointer size. `sizeof(char*)' is 4 on 32-bit machines and 8 on 64-bit machines. As mentioned earlier, the `max_heap_table_size' system variable sets the limit on the maximum size of `MEMORY' tables. To control the maximum size for individual tables, set the session value of this variable before creating each table. (Do not change the global `max_heap_table_size' value unless you intend the value to be used for `MEMORY' tables created by all clients.) The following example creates two `MEMORY' tables, with a maximum size of 1MB and 2MB, respectively: mysql> SET max_heap_table_size = 1024*1024; Query OK, 0 rows affected (0.00 sec) mysql> CREATE TABLE t1 (id INT, UNIQUE(id)) ENGINE = MEMORY; Query OK, 0 rows affected (0.01 sec) mysql> SET max_heap_table_size = 1024*1024*2; Query OK, 0 rows affected (0.00 sec) mysql> CREATE TABLE t2 (id INT, UNIQUE(id)) ENGINE = MEMORY; Query OK, 0 rows affected (0.00 sec) Both tables will revert to the server's global `max_heap_table_size' value if the server restarts. You can also specify a `MAX_ROWS' table option in *Note `CREATE TABLE': create-table. statements for `MEMORY' tables to provide a hint about the number of rows you plan to store in them. This does not enable the table to grow beyond the `max_heap_table_size' value, which still acts as a constraint on maximum table size. For maximum flexibility in being able to use `MAX_ROWS', set `max_heap_table_size' at least as high as the value to which you want each `MEMORY' table to be able to grow. * Additional Resources * * A forum dedicated to the `MEMORY' storage engine is available at `http://forums.mysql.com/list.php?92'.  File: manual.info, Node: example-storage-engine, Next: federated-storage-engine, Prev: memory-storage-engine, Up: storage-engines 14.10 The `EXAMPLE' Storage Engine ================================== The `EXAMPLE' storage engine is a stub engine that does nothing. Its purpose is to serve as an example in the MySQL source code that illustrates how to begin writing new storage engines. As such, it is primarily of interest to developers. To enable the `EXAMPLE' storage engine if you build MySQL from source, invoke `configure' with the `--with-example-storage-engine' option. To examine the source for the `EXAMPLE' engine, look in the `storage/example' directory of a MySQL source distribution. When you create an `EXAMPLE' table, the server creates a table format file in the database directory. The file begins with the table name and has an `.frm' extension. No other files are created. No data can be stored into the table. Retrievals return an empty result. mysql> CREATE TABLE test (i INT) ENGINE = EXAMPLE; Query OK, 0 rows affected (0.78 sec) mysql> INSERT INTO test VALUES(1),(2),(3); ERROR 1031 (HY000): Table storage engine for 'test' doesn't » have this option mysql> SELECT * FROM test; Empty set (0.31 sec) The `EXAMPLE' storage engine does not support indexing.  File: manual.info, Node: federated-storage-engine, Next: archive-storage-engine, Prev: example-storage-engine, Up: storage-engines 14.11 The `FEDERATED' Storage Engine ==================================== * Menu: * federated-description:: `FEDERATED' Storage Engine Overview * federated-create:: How to Create `FEDERATED' Tables * federated-usagenotes:: `FEDERATED' Storage Engine Notes and Tips * federated-storage-engine-resources:: `FEDERATED' Storage Engine Resources The `FEDERATED' storage engine lets you access data from a remote MySQL database without using replication or cluster technology. Querying a local `FEDERATED' table automatically pulls the data from the remote (federated) tables. No data is stored on the local tables. To include the `FEDERATED' storage engine if you build MySQL from source, invoke `configure' with the `--with-federated-storage-engine' option. Beginning with MySQL 5.1.26, the `FEDERATED' storage engine is not enabled by default in the running server; to enable `FEDERATED', you must start the MySQL server binary using the `--federated' option. To examine the source for the `FEDERATED' engine, look in the `storage/federated' directory of a MySQL source distribution.  File: manual.info, Node: federated-description, Next: federated-create, Prev: federated-storage-engine, Up: federated-storage-engine 14.11.1 `FEDERATED' Storage Engine Overview ------------------------------------------- When you create a table using one of the standard storage engines (such as `MyISAM', `CSV' or `InnoDB'), the table consists of the table definition and the associated data. When you create a `FEDERATED' table, the table definition is the same, but the physical storage of the data is handled on a remote server. A `FEDERATED' table consists of two elements: * A _remote server_ with a database table, which in turn consists of the table definition (stored in the `.frm' file) and the associated table. The table type of the remote table may be any type supported by the remote `mysqld' server, including `MyISAM' or `InnoDB'. * A _local server_ with a database table, where the table definition matches that of the corresponding table on the remote server. The table definition is stored within the `.frm' file. However, there is no data file on the local server. Instead, the table definition includes a connection string that points to the remote table. When executing queries and statements on a `FEDERATED' table on the local server, the operations that would normally insert, update or delete information from a local data file are instead sent to the remote server for execution, where they update the data file on the remote server or return matching rows from the remote server. The basic structure of a `FEDERATED' table setup is shown in *Note figure-se-federated-structure::. FIGURE GOES HERE: `FEDERATED' Table Structure When a client issues an SQL statement that refers to a `FEDERATED' table, the flow of information between the local server (where the SQL statement is executed) and the remote server (where the data is physically stored) is as follows: 1. The storage engine looks through each column that the `FEDERATED' table has and constructs an appropriate SQL statement that refers to the remote table. 2. The statement is sent to the remote server using the MySQL client API. 3. The remote server processes the statement and the local server retrieves any result that the statement produces (an affected-rows count or a result set). 4. If the statement produces a result set, each column is converted to internal storage engine format that the `FEDERATED' engine expects and can use to display the result to the client that issued the original statement. The local server communicates with the remote server using MySQL client C API functions. It invokes *Note `mysql_real_query()': mysql-real-query. to send the statement. To read a result set, it uses *Note `mysql_store_result()': mysql-store-result. and fetches rows one at a time using *Note `mysql_fetch_row()': mysql-fetch-row.  File: manual.info, Node: federated-create, Next: federated-usagenotes, Prev: federated-description, Up: federated-storage-engine 14.11.2 How to Create `FEDERATED' Tables ---------------------------------------- * Menu: * federated-create-connection:: Creating a `FEDERATED' Table Using `CONNECTION' * federated-create-server:: Creating a `FEDERATED' Table Using `CREATE SERVER' To create a `FEDERATED' table you should follow these steps: 1. Create the table on the remote server. Alternatively, make a note of the table definition of an existing table, perhaps using the *Note `SHOW CREATE TABLE': show-create-table. statement. 2. Create the table on the local server with an identical table definition, but adding the connection information that links the local table to the remote table. For example, you could create the following table on the remote server: CREATE TABLE test_table ( id INT(20) NOT NULL AUTO_INCREMENT, name VARCHAR(32) NOT NULL DEFAULT '', other INT(20) NOT NULL DEFAULT '0', PRIMARY KEY (id), INDEX name (name), INDEX other_key (other) ) ENGINE=MyISAM DEFAULT CHARSET=latin1; To create the local table that will be federated to the remote table, there are two options available. You can either create the local table and specify the connection string (containing the server name, login, password) to be used to connect to the remote table using the `CONNECTION', or you can use an existing connection that you have previously created using the *Note `CREATE SERVER': create-server. statement. *Important*: When you create the local table it _must_ have an identical field definition to the remote table. *Note*: You can improve the performance of a `FEDERATED' table by adding indexes to the table on the host. The optimization will occur because the query sent to the remote server will include the contents of the `WHERE' clause and will be sent to the remote server and subsequently executed locally. This reduces the network traffic that would otherwise request the entire table from the server for local processing.  File: manual.info, Node: federated-create-connection, Next: federated-create-server, Prev: federated-create, Up: federated-create 14.11.2.1 Creating a `FEDERATED' Table Using `CONNECTION' ......................................................... To use the first method, you must specify the `CONNECTION' string after the engine type in a *Note `CREATE TABLE': create-table. statement. For example: CREATE TABLE federated_table ( id INT(20) NOT NULL AUTO_INCREMENT, name VARCHAR(32) NOT NULL DEFAULT '', other INT(20) NOT NULL DEFAULT '0', PRIMARY KEY (id), INDEX name (name), INDEX other_key (other) ) ENGINE=FEDERATED DEFAULT CHARSET=latin1 CONNECTION='mysql://fed_user@remote_host:9306/federated/test_table'; *Note*: `CONNECTION' replaces the `COMMENT' used in some previous versions of MySQL. The `CONNECTION' string contains the information required to connect to the remote server containing the table that will be used to physically store the data. The connection string specifies the server name, login credentials, port number and database/table information. In the example, the remote table is on the server `remote_host', using port 9306. The name and port number should match the host name (or IP address) and port number of the remote MySQL server instance you want to use as your remote table. The format of the connection string is as follows: SCHEME://USER_NAME[:PASSWORD]@HOST_NAME[:PORT_NUM]/DB_NAME/TBL_NAME Where: * SCHEME: A recognized connection protocol. Only `mysql' is supported as the SCHEME value at this point. * USER_NAME: The user name for the connection. This user must have been created on the remote server, and must have suitable privileges to perform the required actions (*Note `SELECT': select, *Note `INSERT': insert, *Note `UPDATE': update, and so forth) on the remote table. * PASSWORD: (Optional) The corresponding password for USER_NAME. * HOST_NAME: The host name or IP address of the remote server. * PORT_NUM: (Optional) The port number for the remote server. The default is 3306. * DB_NAME: The name of the database holding the remote table. * TBL_NAME: The name of the remote table. The name of the local and the remote table do not have to match. Sample connection strings: CONNECTION='mysql://username:password@hostname:port/database/tablename' CONNECTION='mysql://username@hostname/database/tablename' CONNECTION='mysql://username:password@hostname/database/tablename'  File: manual.info, Node: federated-create-server, Prev: federated-create-connection, Up: federated-create 14.11.2.2 Creating a `FEDERATED' Table Using `CREATE SERVER' ............................................................ If you are creating a number of `FEDERATED' tables on the same server, or if you want to simplify the process of creating `FEDERATED' tables, you can use the *Note `CREATE SERVER': create-server. statement to define the server connection parameters, just as you would with the `CONNECTION' string. The format of the *Note `CREATE SERVER': create-server. statement is: CREATE SERVER SERVER_NAME FOREIGN DATA WRAPPER WRAPPER_NAME OPTIONS (OPTION [, OPTION] ...) The SERVER_NAME is used in the connection string when creating a new `FEDERATED' table. For example, to create a server connection identical to the `CONNECTION' string: CONNECTION='mysql://fed_user@remote_host:9306/federated/test_table'; You would use the following statement: CREATE SERVER fedlink FOREIGN DATA WRAPPER mysql OPTIONS (USER 'fed_user', HOST 'remote_host', PORT 9306, DATABASE 'federated'); To create a `FEDERATED' table that uses this connection, you still use the `CONNECTION' keyword, but specify the name you used in the *Note `CREATE SERVER': create-server. statement. CREATE TABLE test_table ( id INT(20) NOT NULL AUTO_INCREMENT, name VARCHAR(32) NOT NULL DEFAULT '', other INT(20) NOT NULL DEFAULT '0', PRIMARY KEY (id), INDEX name (name), INDEX other_key (other) ) ENGINE=FEDERATED DEFAULT CHARSET=latin1 CONNECTION='fedlink/test_table'; The connection name in this example contains the name of the connection (`fedlink') and the name of the table (`test_table') to link to, separated by a slash. If you specify only the connection name without a table name, the table name of the local table is used instead. For more information on *Note `CREATE SERVER': create-server, see *Note create-server::. The *Note `CREATE SERVER': create-server. statement accepts the same arguments as the `CONNECTION' string. The *Note `CREATE SERVER': create-server. statement updates the rows in the `mysql.servers' table. See the following table for information on the correspondence between parameters in a connection string, options in the *Note `CREATE SERVER': create-server. statement, and the columns in the `mysql.servers' table. For reference, the format of the `CONNECTION' string is as follows: SCHEME://USER_NAME[:PASSWORD]@HOST_NAME[:PORT_NUM]/DB_NAME/TBL_NAME Description `CONNECTION' *Note `CREATE `mysql.servers' string SERVER': column create-server. option Connection scheme SCHEME `wrapper_name' `Wrapper' Remote user USER_NAME `USER' `Username' Remote password PASSWORD `PASSWORD' `Password' Remote host HOST_NAME `HOST' `Host' Remote port PORT_NUM `PORT' `Port' Remote database DB_NAME `DATABASE' `Db'  File: manual.info, Node: federated-usagenotes, Next: federated-storage-engine-resources, Prev: federated-create, Up: federated-storage-engine 14.11.3 `FEDERATED' Storage Engine Notes and Tips ------------------------------------------------- You should be aware of the following points when using the `FEDERATED' storage engine: * `FEDERATED' tables may be replicated to other slaves, but you must ensure that the slave servers are able to use the user/password combination that is defined in the `CONNECTION' string (or the row in the `mysql.servers' table) to connect to the remote server. The following items indicate features that the `FEDERATED' storage engine does and does not support: * The remote server must be a MySQL server. * The remote table that a `FEDERATED' table points to _must_ exist before you try to access the table through the `FEDERATED' table. * It is possible for one `FEDERATED' table to point to another, but you must be careful not to create a loop. * A `FEDERATED' table does not support indexes per se. Because access to the table is handled remotely, it is the remote table that supports the indexes. Care should be taken when creating a `FEDERATED' table since the index definition from an equivalent `MyISAM' or other table may not be supported. For example, creating a `FEDERATED' table with an index prefix on *Note `VARCHAR': char, *Note `TEXT': blob. or *Note `BLOB': blob. columns will fail. The following definition in `MyISAM' is valid: CREATE TABLE `T1`(`A` VARCHAR(100),UNIQUE KEY(`A`(30))) ENGINE=MYISAM; The key prefix in this example is incompatible with the `FEDERATED' engine, and the equivalent statement will fail: CREATE TABLE `T1`(`A` VARCHAR(100),UNIQUE KEY(`A`(30))) ENGINE=FEDERATED CONNECTION='MYSQL://127.0.0.1:3306/TEST/T1'; If possible, you should try to separate the column and index definition when creating tables on both the remote server and the local server to avoid these index issues. * Internally, the implementation uses *Note `SELECT': select, *Note `INSERT': insert, *Note `UPDATE': update, and *Note `DELETE': delete, but not *Note `HANDLER': handler. * The `FEDERATED' storage engine supports *Note `SELECT': select, *Note `INSERT': insert, *Note `UPDATE': update, *Note `DELETE': delete, *Note `TRUNCATE TABLE': truncate-table, and indexes. It does not support *Note `ALTER TABLE': alter-table, or any Data Definition Language statements that directly affect the structure of the table, other than *Note `DROP TABLE': drop-table. The current implementation does not use prepared statements. * `FEDERATED' accepts *Note `INSERT ... ON DUPLICATE KEY UPDATE': insert-on-duplicate. statements, but if a duplicate-key violation occurs, the statement fails with an error. * Performance on a `FEDERATED' table when performing bulk inserts (for example, on a *Note `INSERT INTO ... SELECT ...': insert-select. statement) is slower than with other table types because each selected row is treated as an individual *Note `INSERT': insert. statement on the `FEDERATED' table. * Transactions are not supported. * Before MySQL 5.1.21, for a multiple-row insert into a `FEDERATED' table that refers to a remote transactional table, if the insert failed for a row due to constraint failure, the remote table would contain a partial commit (the rows preceding the failed one) instead of rolling back the statement completely. This occurred because the rows were treated as individual inserts. As of MySQL 5.1.21, `FEDERATED' performs bulk-insert handling such that multiple rows are sent to the remote table in a batch. This provides a performance improvement and enables the remote table to perform improvement. Also, if the remote table is transactional, it enables the remote storage engine to perform statement rollback properly should an error occur. This capability has the following limitations: * The size of the insert cannot exceed the maximum packet size between servers. If the insert exceeds this size, it is broken into multiple packets and the rollback problem can occur. * Bulk-insert handling does not occur for *Note `INSERT ... ON DUPLICATE KEY UPDATE': insert-on-duplicate. * There is no way for the `FEDERATED' engine to know if the remote table has changed. The reason for this is that this table must work like a data file that would never be written to by anything other than the database system. The integrity of the data in the local table could be breached if there was any change to the remote database. * When using a `CONNECTION' string, you cannot use an '@' character in the password. You can get round this limitation by using the *Note `CREATE SERVER': create-server. statement to create a server connection. * The `insert_id' and `timestamp' options are not propagated to the data provider. * Any *Note `DROP TABLE': drop-table. statement issued against a `FEDERATED' table drops only the local table, not the remote table. * `FEDERATED' tables do not work with the query cache. * User-defined partitioning is not supported for `FEDERATED' tables. Beginning with MySQL 5.1.15, it is no longer possible to create such tables at all.  File: manual.info, Node: federated-storage-engine-resources, Prev: federated-usagenotes, Up: federated-storage-engine 14.11.4 `FEDERATED' Storage Engine Resources -------------------------------------------- The following additional resources are available for the `FEDERATED' storage engine: * A forum dedicated to the `FEDERATED' storage engine is available at `http://forums.mysql.com/list.php?105'.  File: manual.info, Node: archive-storage-engine, Next: csv-storage-engine, Prev: federated-storage-engine, Up: storage-engines 14.12 The `ARCHIVE' Storage Engine ================================== The `ARCHIVE' storage engine is used for storing large amounts of data without indexes in a very small footprint. *`ARCHIVE' Storage Engine Features* *Storage limits* None *Transactions* No *Locking Row granularity* *MVCC* No *Geospatial Yes *Geospatial No data type indexing support* support* *B-tree indexes* No *Hash indexes* No *Full-text No search indexes* *Clustered No *Data caches* No *Index caches* No indexes* *Compressed Yes *Encrypted data Yes *Cluster No data* Implemented in database the server (via support* encryption functions), rather than in the storage engine.* *Replication Yes *Foreign key No *Backup / Yes support support* point-in-time Implemented in recovery the server, Implemented in rather than in the server, the storage rather than in product.* the storage product.* *Query cache Yes *Update Yes support* statistics for data dictionary* The `ARCHIVE' storage engine is included in MySQL binary distributions. To enable this storage engine if you build MySQL from source, invoke `configure' with the `--with-archive-storage-engine' option. To examine the source for the `ARCHIVE' engine, look in the `storage/archive' directory of a MySQL source distribution. You can check whether the `ARCHIVE' storage engine is available with the *Note `SHOW ENGINES': show-engines. statement. When you create an `ARCHIVE' table, the server creates a table format file in the database directory. The file begins with the table name and has an `.frm' extension. The storage engine creates other files, all having names beginning with the table name. The data file has an extension of `.ARZ'. (Prior to MySQL 5.1.15, a metadata file with an extension of `.ARM' is created as well.) An `.ARN' file may appear during optimization operations. The `ARCHIVE' engine supports *Note `INSERT': insert. and *Note `SELECT': select, but not *Note `DELETE': delete, *Note `REPLACE': replace, or *Note `UPDATE': update. It does support `ORDER BY' operations, *Note `BLOB': blob. columns, and basically all but spatial data types (see *Note mysql-spatial-datatypes::). The `ARCHIVE' engine uses row-level locking. As of MySQL 5.1.6, the `ARCHIVE' engine supports the `AUTO_INCREMENT' column attribute. The `AUTO_INCREMENT' column can have either a unique or nonunique index. Attempting to create an index on any other column results in an error. The `ARCHIVE' engine also supports the `AUTO_INCREMENT' table option in *Note `CREATE TABLE': create-table. and *Note `ALTER TABLE': alter-table. statements to specify the initial sequence value for a new table or reset the sequence value for an existing table, respectively. As of MySQL 5.1.6, the `ARCHIVE' engine ignores *Note `BLOB': blob. columns if they are not requested and scans past them while reading. Formerly, the following two statements had the same cost, but as of 5.1.6, the second is much more efficient than the first: SELECT a, b, blob_col FROM archive_table; SELECT a, b FROM archive_table; *Storage:* Rows are compressed as they are inserted. The `ARCHIVE' engine uses `zlib' lossless data compression (see `http://www.zlib.net/'). You can use *Note `OPTIMIZE TABLE': optimize-table. to analyze the table and pack it into a smaller format (for a reason to use *Note `OPTIMIZE TABLE': optimize-table, see later in this section). The engine also supports *Note `CHECK TABLE': check-table. There are several types of insertions that are used: * An *Note `INSERT': insert. statement just pushes rows into a compression buffer, and that buffer flushes as necessary. The insertion into the buffer is protected by a lock. A *Note `SELECT': select. forces a flush to occur, unless the only insertions that have come in were *Note `INSERT DELAYED': insert-delayed. (those flush as necessary). See *Note insert-delayed::. * A bulk insert is visible only after it completes, unless other inserts occur at the same time, in which case it can be seen partially. A *Note `SELECT': select. never causes a flush of a bulk insert unless a normal insert occurs while it is loading. *Retrieval*: On retrieval, rows are uncompressed on demand; there is no row cache. A *Note `SELECT': select. operation performs a complete table scan: When a *Note `SELECT': select. occurs, it finds out how many rows are currently available and reads that number of rows. *Note `SELECT': select. is performed as a consistent read. Note that lots of *Note `SELECT': select. statements during insertion can deteriorate the compression, unless only bulk or delayed inserts are used. To achieve better compression, you can use *Note `OPTIMIZE TABLE': optimize-table. or *Note `REPAIR TABLE': repair-table. The number of rows in `ARCHIVE' tables reported by *Note `SHOW TABLE STATUS': show-table-status. is always accurate. See *Note optimize-table::, *Note repair-table::, and *Note show-table-status::. * Additional Resources * * A forum dedicated to the `ARCHIVE' storage engine is available at `http://forums.mysql.com/list.php?112'.  File: manual.info, Node: csv-storage-engine, Next: blackhole-storage-engine, Prev: archive-storage-engine, Up: storage-engines 14.13 The `CSV' Storage Engine ============================== * Menu: * se-csv-repair:: Repairing and Checking CSV Tables * se-csv-limitations:: CSV Limitations The `CSV' storage engine stores data in text files using comma-separated values format. To enable the `CSV' storage engine if you build MySQL from source, invoke `configure' with the `--with-csv-storage-engine' option. To examine the source for the `CSV' engine, look in the `storage/csv' directory of a MySQL source distribution. When you create a `CSV' table, the server creates a table format file in the database directory. The file begins with the table name and has an `.frm' extension. The storage engine also creates a data file. Its name begins with the table name and has a `.CSV' extension. The data file is a plain text file. When you store data into the table, the storage engine saves it into the data file in comma-separated values format. mysql> CREATE TABLE test (i INT NOT NULL, c CHAR(10) NOT NULL) -> ENGINE = CSV; Query OK, 0 rows affected (0.12 sec) mysql> INSERT INTO test VALUES(1,'record one'),(2,'record two'); Query OK, 2 rows affected (0.00 sec) Records: 2 Duplicates: 0 Warnings: 0 mysql> SELECT * FROM test; +------+------------+ | i | c | +------+------------+ | 1 | record one | | 2 | record two | +------+------------+ 2 rows in set (0.00 sec) Starting with MySQL 5.1.9, creating a CSV table also creates a corresponding Metafile that stores the state of the table and the number of rows that exist in the table. The name of this file is the same as the name of the table with the extension `CSM'. If you examine the `test.CSV' file in the database directory created by executing the preceding statements, its contents should look like this: "1","record one" "2","record two" This format can be read, and even written, by spreadsheet applications such as Microsoft Excel or StarOffice Calc.  File: manual.info, Node: se-csv-repair, Next: se-csv-limitations, Prev: csv-storage-engine, Up: csv-storage-engine 14.13.1 Repairing and Checking CSV Tables ----------------------------------------- *Functionality introduced in version 5.1.9* The CSV storage engines supports the `CHECK' and `REPAIR' statements to verify and if possible repair a damaged CSV table. When running the `CHECK' statement, the CSV file will be checked for validity by looking for the correct field separators, escaped fields (matching or missing quotation marks), the correct number of fields compared to the table definition and the existence of a corresponding CSV metafile. The first invalid row discovered will report an error. Checking a valid table produces output like that shown below: mysql> check table csvtest; +--------------+-------+----------+----------+ | Table | Op | Msg_type | Msg_text | +--------------+-------+----------+----------+ | test.csvtest | check | status | OK | +--------------+-------+----------+----------+ 1 row in set (0.00 sec) A check on a corrupted table returns a fault: mysql> check table csvtest; +--------------+-------+----------+----------+ | Table | Op | Msg_type | Msg_text | +--------------+-------+----------+----------+ | test.csvtest | check | error | Corrupt | +--------------+-------+----------+----------+ 1 row in set (0.01 sec) If the check fails, the table is marked as crashed (corrupt). Once a table has been marked as corrupt, it is automatically repaired when you next run `CHECK' or execute a *Note `SELECT': select. statement. The corresponding corrupt status and new status will be displayed when running `CHECK': mysql> check table csvtest; +--------------+-------+----------+----------------------------+ | Table | Op | Msg_type | Msg_text | +--------------+-------+----------+----------------------------+ | test.csvtest | check | warning | Table is marked as crashed | | test.csvtest | check | status | OK | +--------------+-------+----------+----------------------------+ 2 rows in set (0.08 sec) To repair a table you can use `REPAIR', this copies as many valid rows from the existing CSV data as possible, and then replaces the existing CSV file with the recovered rows. Any rows beyond the corrupted data are lost. mysql> repair table csvtest; +--------------+--------+----------+----------+ | Table | Op | Msg_type | Msg_text | +--------------+--------+----------+----------+ | test.csvtest | repair | status | OK | +--------------+--------+----------+----------+ 1 row in set (0.02 sec) *Warning*: Note that during repair, only the rows from the CSV file up to the first damaged row are copied to the new table. All other rows from the first damaged row to the end of the table are removed, even valid rows.  File: manual.info, Node: se-csv-limitations, Prev: se-csv-repair, Up: csv-storage-engine 14.13.2 CSV Limitations ----------------------- *Important*: The `CSV' storage engine does not support indexing. Partitioning is not supported for tables using the `CSV' storage engine. Beginning with MySQL 5.1.12, it is no longer possible to create partitioned `CSV' tables. (See Bug#19307) Beginning with MySQL 5.1.23, tables using the `CSV' storage engine can no longer be created with `NULL' columns. However, for backward compatibility, you can continue to use such tables that were created in previous MySQL releases. (Bug#32050)  File: manual.info, Node: blackhole-storage-engine, Prev: csv-storage-engine, Up: storage-engines 14.14 The `BLACKHOLE' Storage Engine ==================================== The `BLACKHOLE' storage engine acts as a `black hole' that accepts data but throws it away and does not store it. Retrievals always return an empty result: mysql> CREATE TABLE test(i INT, c CHAR(10)) ENGINE = BLACKHOLE; Query OK, 0 rows affected (0.03 sec) mysql> INSERT INTO test VALUES(1,'record one'),(2,'record two'); Query OK, 2 rows affected (0.00 sec) Records: 2 Duplicates: 0 Warnings: 0 mysql> SELECT * FROM test; Empty set (0.00 sec) To enable the `BLACKHOLE' storage engine if you build MySQL from source, invoke `configure' with the `--with-blackhole-storage-engine' option. To examine the source for the `BLACKHOLE' engine, look in the `sql' directory of a MySQL source distribution. When you create a `BLACKHOLE' table, the server creates a table format file in the database directory. The file begins with the table name and has an `.frm' extension. There are no other files associated with the table. The `BLACKHOLE' storage engine supports all kinds of indexes. That is, you can include index declarations in the table definition. You can check whether the `BLACKHOLE' storage engine is available with the *Note `SHOW ENGINES': show-engines. statement. Inserts into a `BLACKHOLE' table do not store any data, but if the binary log is enabled, the SQL statements are logged (and replicated to slave servers). This can be useful as a repeater or filter mechanism. Suppose that your application requires slave-side filtering rules, but transferring all binary log data to the slave first results in too much traffic. In such a case, it is possible to set up on the master host a `dummy' slave process whose default storage engine is `BLACKHOLE', depicted as follows: Replication using `BLACKHOLE' for filtering The master writes to its binary log. The `dummy' *Note `mysqld': mysqld. process acts as a slave, applying the desired combination of `replicate-do-*' and `replicate-ignore-*' rules, and writes a new, filtered binary log of its own. (See *Note replication-options::.) This filtered log is provided to the slave. The dummy process does not actually store any data, so there is little processing overhead incurred by running the additional *Note `mysqld': mysqld. process on the replication master host. This type of setup can be repeated with additional replication slaves. *Note `INSERT': insert. triggers for `BLACKHOLE' tables work as expected. However, because the `BLACKHOLE' table does not actually store any data, *Note `UPDATE': update. and *Note `DELETE': delete. triggers are not activated: The `FOR EACH ROW' clause in the trigger definition does not apply because there are no rows. Other possible uses for the `BLACKHOLE' storage engine include: * Verification of dump file syntax. * Measurement of the overhead from binary logging, by comparing performance using `BLACKHOLE' with and without binary logging enabled. * `BLACKHOLE' is essentially a `no-op' storage engine, so it could be used for finding performance bottlenecks not related to the storage engine itself. The `BLACKHOLE' storage engine does not support *Note `INSERT DELAYED': insert-delayed, *Note `LOCK TABLES': lock-tables, or *Note `UNLOCK TABLES': lock-tables. statements prior to MySQL 5.1.19. As of MySQL 5.1.4, the `BLACKHOLE' engine is transaction-aware, in the sense that committed transactions are written to the binary log and rolled-back transactions are not. *Blackhole Engine and Auto Increment Columns* The Blackhole engine is a no-op engine. Any operations performed on a table using Blackhole will have no effect. This should be born in mind when considering the behavior of primary key columns that auto increment. The engine will not automatically increment field values, and does not retain auto increment field state. This has important implications in replication. Consider the following replication scenario where all three of the following conditions apply: 1. On a master server there is a blackhole table with an auto increment field that is a primary key. 2. On a slave the same table exists but using the MyISAM engine. 3. Inserts are performed into the master's table without explicitly setting the auto increment value in the `INSERT' statement itself or through using a `SET INSERT_ID' statement. In this scenario replication will fail with a duplicate entry error on the primary key column. In statement based replication, the value of `INSERT_ID' in the context event will always be the same. Replication will therefore fail due to trying insert a row with a duplicate value for a primary key column. In row based replication, the value that the engine returns for the row always be the same for each insert. This will result in the slave attempting to replay two insert log entries using the same value for the primary key column, and so replication will fail. *Column Filtering* When using row-based replication, (`binlog_format=ROW'), a slave where the last columns are missing from a table is supported, as described in the section *Note replication-features-differing-tables::. This filtering works on the slave side, that is, the columns are copied to the slave before they are filtered out. There are at least two cases where it is not desirable to copy the columns to the slave: 1. If the data is confidential, so the slave server should not have access to it. 2. If the master has many slaves, filtering before sending to the slaves may reduce network traffic. Master column filtering can be achieved using the `BLACKHOLE' engine. This is carried out in a way similar to how master table filtering is achieved - by using the `BLACKHOLE' engine and the option `--replicate-[do|ignore]-table'. The setup for the master is: CREATE TABLE t1 (public_col_1, ..., public_col_N, secret_col_1, ..., secret_col_M) ENGINE=MyISAM; The setup for the trusted slave is: CREATE TABLE t1 (public_col_1, ..., public_col_N) ENGINE=BLACKHOLE; The setup for the untrusted slave is: CREATE TABLE t1 (public_col_1, ..., public_col_N) ENGINE=MyISAM;  File: manual.info, Node: ha-overview, Next: replication, Prev: storage-engines, Up: Top 15 High Availability and Scalability ************************************ * Menu: * ha-ovm-template:: Oracle VM Template for MySQL Enterprise Edition * ha-drbd:: Using MySQL with DRBD * ha-heartbeat:: Using Linux HA Heartbeat * ha-vm:: Using MySQL within an Amazon EC2 Instance * ha-zfs-replication:: Using ZFS Replication * ha-memcached:: Using MySQL with `memcached' * mysql-proxy:: MySQL Proxy MySQL is deployed into many applications demanding availability and scalability. Availability refers to the ability to cope with, and if necessary recover from, failures on the host, including failures of MySQL, the operating system, or the hardware and maintenance activity that may otherwise cause downtime. Scalability refers to the ability to spread both the database and the load of your application queries across multiple MySQL servers. Because each application has different operational and availability requirements, MySQL offers a range of certified and supported solutions, delivering the appropriate levels of High Availability (HA) and scalability to meet service level requirements. Such solutions extend from replication, through virtualization and geographically redundant, multi-data center solutions delivering 99.999% uptime. Selecting the right high availability solution for an application largely depends on: * The level of availability required. * The type of application being deployed. * Accepted best practices within your own environment. The primary solutions supported by MySQL include: * MySQL Replication. Learn more: `http://dev.mysql.com/doc/refman/5.5/en/replication.html' * MySQL Cluster. Learn more: `http://dev.mysql.com/doc/refman/5.1/en/mysql-cluster.html' * Oracle VM Template for MySQL. Learn more: *Note ha-ovm-template::. Further options are available using third-party solutions such as DRBD (Distributed Replicated Block Device) and Heartbeat, and more complex scenarios can be solved through a combination of these technologies. Each architecture used to achieve highly available database services is differentiated by the levels of uptime it offers. These architectures can be grouped into three main categories: * Data Replication. * Clustered & Virtualized Systems. * Shared-Nothing, Geographically-Replicated Clusters. As illustrated in the following figure, each of these architectures offers progressively higher levels of uptime, which must be balanced against potentially greater levels of cost and complexity that each can incur. Simply deploying a high availability architecture is not a guarantee of actually delivering HA. In fact, a poorly implemented and maintained shared-nothing cluster could easily deliver lower levels of availability than a simple data replication solution. FIGURE GOES HERE: Tradeoffs: Cost and Complexity versus Availability The following figure maps common application types to architectures, based on best practices observed from the MySQL user base. It serves as a reference point to investigate which HA architectures can best serve your requirements. FIGURE GOES HERE: High Availability Architectures for Common Application Types The following table compares the HA and Scalability capabilities of the various MySQL solutions: Requirement MySQL MySQL Heartbeat + Oracle VM MySQL Replication Replication DRBD Template Cluster + Linux Heartbeat *Availability* Platform All Linux Linux Oracle Linux All Support Supported Supported by MySQL by MySQL Server Cluster (http://www.mysql.com/support/supportedplatforms/database.html) (http://www.mysql.com/support/supportedplatforms/cluster.html) Automated IP No Yes Yes Yes Depends on Failover Connector and Configuration Automated No No Yes Yes Yes Database Failover Automatic No No Yes N/A - Yes Data Shared Resynchronization Storage Typical User / ConfigurationConfigurationConfiguration1 Second Failover Time Script Dependent, Dependent, Dependent, and Less Dependent 60 seconds 60 seconds 60 seconds and Above and Above and Above Synchronous No, No, Yes N/A - Yes Replication Asynchronous Asynchronous Shared and and Storage Semi-SynchronousSemi-Synchronous Shared Storage No, No, No, Yes No, Distributed Distributed Distributed Distributed Geographic Yes Yes Yes, via Yes, via Yes, via redundancy MySQL MySQL MySQL support Replication Replication Replication Update Schema No No No No Yes On-Line *Scalability* Number of One Master, One Master, One Active One Active 255 Nodes Multiple Multiple (primary), (primary), Slaves Slaves one Passive one Passive (secondary) (secondary) Node Node Built-in Load Reads, via Reads, via Reads, via Reads, via Yes, Reads Balancing MySQL MySQL MySQL MySQL and Writes Replication Replication Replication Replication & During Failover Supports Yes Yes Yes Yes Yes Read-Intensive Workloads Supports Yes, via Yes, via Yes, via Yes, via Yes, via Write-IntensiveApplication-LevelApplication-LevelApplication-LevelApplication-LevelAuto-Sharding Workloads Sharding Sharding Sharding to Sharding to Multiple Multiple Active/PassiveActive/Passive Pairs Pairs Scale On-Line No No No No Yes (add nodes, repartition, etc.)  File: manual.info, Node: ha-ovm-template, Next: ha-drbd, Prev: ha-overview, Up: ha-overview 15.1 Oracle VM Template for MySQL Enterprise Edition ==================================================== Virtualization is a key technology to enable data center efficiency and high availability while providing the foundation for cloud computing. Integrating MySQL Enterprise Edition with Oracle Linux, the Oracle VM Template is the fastest, easiest, and most reliable way to provision virtualized MySQL instances, enabling users to meet the explosive demand for highly available services. The Oracle VM Template enables rapid deployment and eliminates manual configuration efforts. It provides a pre-installed and pre-configured virtualized MySQL 5.5 Enterprise Edition software image running on Oracle Linux and Oracle VM, certified for production use. The MySQL software image has undergone extensive integration and quality assurance testing as part of the development process. In addition to rapid provisioning, MySQL users also benefit from the integrated high availability features of Oracle VM which are designed to enable organizations to meet stringent SLA (Service Level Agreement) demands through a combination of: * *Automatic recovery from failures*, with Oracle VM automatically restarting failed instances on available servers in the server pool after outages of the physical server, VM or MySQL database. * *Live Migration*, enabling operations staff to move running instances of MySQL to alternative hosts within a server pool when they need to perform maintenance operations. Instructions for the creation, deployment and use of the Oracle VM Template for MySQL Enterprise Edition are available from: * The Oracle VM Template for MySQL Enterprise Edition whitepaper: `http://www.mysql.com/why-mysql/white-papers/mysql_wp_oracle-vm-template-for-mee.php'. * The README file accompanying the download of the Template. To download the Oracle VM Template for MySQL Enterprise, go to `http://edelivery.oracle.com/oraclevm' and follow these instructions: * Complete your registration information (Name, Company Name, Email Address and Country) and click on the download agreement. * Select "Oracle VM Templates" from the "Select a Product Pack" pull-down menu and click "Go". * Select MySQL Enterprise from the list of Oracle VM Templates. * Download and unzip the files and refer to the README for further instructions.  File: manual.info, Node: ha-drbd, Next: ha-heartbeat, Prev: ha-ovm-template, Up: ha-overview 15.2 Using MySQL with DRBD ========================== * Menu: * ha-drbd-install:: Configuring the DRBD Environment * ha-drbd-install-mysql:: Configuring MySQL for DRBD * ha-drbd-performance:: Optimizing Performance and Reliability The Distributed Replicated Block Device (DRBD) is a Linux Kernel module that constitutes a distributed storage system. You can use DRBD to share block devices between Linux servers and, in turn, share file systems and data. DRBD implements a block device which can be used for storage and which is replicated from a primary server to one or more secondary servers. The distributed block device is handled by the DRBD service. Writes to the DRBD block device are distributed among the servers. Each DRBD service writes the information from the DRBD block device to a local physical block device (hard disk). On the primary data writes are written both to the underlying physical block device and distributed to the secondary DRBD services. On the secondary, the writes received through DRBD and written to the local physical block device. On both the primary and the secondary, reads from the DRBD block device are handled by the underlying physical block device. The information is shared between the primary DRBD server and the secondary DRBD server synchronously and at a block level, and this means that DRBD can be used in high-availability solutions where you need failover support. FIGURE GOES HERE: DRBD Architecture Overview When used with MySQL, DRBD can be used to ensure availability in the event of a failure. MySQL is configured to store information on the DRBD block device, with one server acting as the primary and a second machine available to operate as an immediate replacement in the event of a failure. For automatic failover support you can combine DRBD with the Linux Heartbeat project, which manages the interfaces on the two servers and automatically configures the secondary (passive) server to replace the primary (active) server in the event of a failure. You can also combine DRBD with MySQL Replication to provide both failover and scalability within your MySQL environment. For information on how to configure DRBD and MySQL, including Heartbeat support, see *Note ha-drbd-install::. An FAQ for using DRBD and MySQL is available. See *Note faqs-mysql-drbd-heartbeat::. *Note*: Because DRBD is a Linux Kernel module it is currently not supported on platforms other than Linux.  File: manual.info, Node: ha-drbd-install, Next: ha-drbd-install-mysql, Prev: ha-drbd, Up: ha-drbd 15.2.1 Configuring the DRBD Environment --------------------------------------- * Menu: * ha-drbd-install-os:: Setting Up Your Operating System for DRBD * ha-drbd-install-drbd:: Installing and Configuring DRBD * ha-drbd-install-drbd-primary:: Setting Up a DRBD Primary Node * ha-drbd-install-drbd-secondary:: Setting Up a DRBD Secondary Node * ha-drbd-install-drbd-using:: Monitoring DRBD Device * ha-drbd-install-drbd-management:: Managing your DRBD Installation * ha-drbd-install-drbd-othercfg:: Additional DRBD Configuration Options To set up DRBD, MySQL and Heartbeat you need to follow a number of steps that affect the operating system, DRBD and your MySQL installation. Before starting the installation process, be aware of the following information, terms and requirements on using DRBD: * DRBD is a solution for enabling high-availability, and therefore you need to ensure that the two machines within your DRBD setup are as identically configured as possible so that the secondary machine can act as a direct replacement for the primary machine in the event of system failure. * DRBD works through two (or more) servers, each called a _node_ * The node that contains the primary data, has read/write access to the data, and in an HA environment is the currently active node is called the _primary_. * The server to which the data is replicated is referred as _secondary_. * A collection of nodes that are sharing information are referred to as a _DRBD cluster_. * For DRBD to operate you must have a block device on which the information can be stored on _each_ DRBD node. The _lower level_ block device can be a physical disk partition, a partition from a volume group or RAID device or any other block device. Typically you use a spare partition on which the physical data is stored. On the primary node, this disk holds the raw data that you want replicated. On the secondary nodes, the disk holds the data replicated to the secondary server by the DRBD service. Ideally, the size of the partition on the two DRBD servers should be identical, but this is not necessary as long as there is enough space to hold the data that you want distributed between the two servers. * For the distribution of data to work, DRBD is used to create a logical block device that uses the lower level block device for the actual storage of information. To store information on the distributed device, a file system is created on the DRBD logical block device. * When used with MySQL, once the file system has been created, you move the MySQL data directory (including InnoDB data files and binary logs) to the new file system. * When you set up the secondary DRBD server, you set up the physical block device and the DRBD logical block device that stores the data. The block device data is then copied from the primary to the secondary server. The overview for the installation and configuration sequence is as follows: 1. First you need to set up your operating system and environment. This includes setting the correct host name, updating the system and preparing the available packages and software required by DRBD, and configuring a physical block device to be used with the DRBD block device. See *Note ha-drbd-install-os::. 2. Installing DRBD requires installing or compiling the DRBD source code and then configuring the DRBD service to set up the block devices to be shared. See *Note ha-drbd-install-drbd::. 3. Once DRBD has been configured, you must alter the configuration and storage location of the MySQL data. See *Note ha-drbd-install-mysql::. You may optionally want to configure high availability using the Linux Heartbeat service. See *Note ha-heartbeat::, for more information.  File: manual.info, Node: ha-drbd-install-os, Next: ha-drbd-install-drbd, Prev: ha-drbd-install, Up: ha-drbd-install 15.2.1.1 Setting Up Your Operating System for DRBD .................................................. To set your Linux environment for using DRBD there are a number of system configuration steps that you must follow. * Make sure that the primary and secondary DRBD servers have the correct host name, and that the host names are unique. You can verify this by using the `uname' command: shell> uname -n drbd-one If the host name is not set correctly, edit the appropriate file (usually `/etc/sysconfig/network', `/etc/hostname', or `/etc/conf.d/hostname') and set the name correctly. * Each DRBD node must have a unique IP address. Make sure that the IP address information is set correctly within the network configuration and that the host name and IP address has been set correctly within the `/etc/hosts' file. * Although you can rely on the DNS or NIS system for host resolving, in the event of a major network failure these services may not be available. If possible, add the IP address and host name of each DRBD node into the `/etc/hosts' file for each machine. This ensures that the node information can always be determined even if the DNS/NIS servers are unavailable. * As a general rule, the faster your network connection the better. Because the block device data is exchanged over the network, everything that is written to the local disk on the DRBD primary is also written to the network for distribution to the DRBD secondary. For tips on configuring a faster network connection see *Note ha-drbd-performance::. * You must have a spare disk or disk partition that you can use as the physical storage location for the DRBD data that is replicated. You do not have to have a complete disk available, a partition on an existing disk is acceptable. If the disk is unpartitioned, partition the disk using `fdisk', `cfdisk' or other partitioning solution. Do not create a file system on the new partition. Remember that you must have a physical disk available for the storage of the replicated information on each DRBD node. Ensure that the physical partition on the DRBD secondary is at least as big as the partitions on the DRBD primary node. Ideally the partitions that are used on each node should have identical sizes, although this is not strictly necessary. * If possible, upgrade your system to the latest available Linux kernel for your distribution. Once the kernel has been installed, you must reboot to make the kernel active. To use DRBD, you must also install the relevant kernel development and header files that are required for building kernel modules. Platform specification information for this is available later in this section. Before you compile or install DRBD, you must make sure the following tools and files are in place: * Kernel header files * Kernel source files * GCC Compiler * `glib 2' * `flex' Here are some operating system specific tips for setting up your installation: * *Tips for Red Hat (including CentOS and Fedora)*: Use `up2date' or `yum' to update and install the latest kernel and kernel header files: root-shell> up2date kernel-smp-devel kernel-smp Reboot. If you are going to build DRBD from source, then update your system with the required development packages: root-shell> up2date glib-devel openssl-devel libgcrypt-devel glib2-devel \ pkgconfig ncurses-devel rpm-build rpm-devel redhat-rpm-config gcc \ gcc-c++ bison flex gnutls-devel lm_sensors-devel net-snmp-devel \ python-devel bzip2-devel libselinux-devel perl-DBI If you are going to use the pre-built DRBD RPMs: root-shell> up2date gnutls lm_sensors net-snmp ncurses libgcrypt glib2 openssl glib * *Tips for Debian, Ubuntu, Kubuntu*: Use `apt-get' to install the kernel packages root-shell> apt-get install linux-headers linux-image-server If you are going to use the pre-built Debian packages for DRBD, you do not need any additional packages. If you want to build DRBD from source, use the following command to install the required components: root-shell> apt-get install devscripts flex bison build-essential \ dpkg-dev kernel-package debconf-utils dpatch debhelper \ libnet1-dev e2fslibs-dev libglib2.0-dev automake1.9 \ libgnutls-dev libtool libltdl3 libltdl3-dev * *Tips for Gentoo*: Gentoo is a source based Linux distribution and therefore many of the source files and components that you need are either already installed or are installed automatically by `emerge'. To install DRBD 0.8.x, you must unmask the `sys-cluster/drbd' build by adding the following line to `/etc/portage/package.keywords': sys-cluster/drbd ~x86 sys-cluster/drbd-kernel ~x86 To enable the DRBD kernel module, you must rebuild your kernel, although the method depends on the kernel version you are using. Determine your current kernel version using `uname -a'. * For Linux kernels lower than 2.6.33, enable the userspace kernelspace linker to build and load the DRBD kernel driver. To enable the kernelspace linker, rebuild the kernel with this option. The best way to do this is to use `genkernel' with the `--menuconfig' option to select the option and then rebuild the kernel. For example, at the command line as `root': root-shell> genkernel --menuconfig all Then through the menu options, select `Device Drivers', `Connector - unified userspace <-> kernelspace linker' and finally press 'y' or 'space' to select the `Connector - unified userspace <-> kernelspace linker' option. After you exit the menu configuration, the kernel is rebuilt and installed. If this is a new kernel, update your bootloader to point to the kernel if the kernel version is different than your current kernel version. Now reboot to enable the new kernel. * For Linux Kernel 2.6.33 and later, DRBD is included within the kernel sources. To enable the DRBD module you must rebuild your kernel. The best way to do this is to use `genkernel' with the `--menuconfig' option to select the option and then rebuild the kernel. For example, at the command line as `root': root-shell> genkernel --menuconfig all Then through the menu options, select `Device Drivers', `Block Devices', and then `DRBD Distributed Replicated Block Device support'. After you exit the menu configuration, the kernel is rebuilt and installed. If this is a new kernel, update your bootloader to point to the kernel if the kernel version is different than your current kernel version. Now reboot to enable the new kernel.  File: manual.info, Node: ha-drbd-install-drbd, Next: ha-drbd-install-drbd-primary, Prev: ha-drbd-install-os, Up: ha-drbd-install 15.2.1.2 Installing and Configuring DRBD ........................................ To install DRBD you can choose either the pre-built binary installation packages or you can use the source packages and build from source. If you want to build from source you must have installed the source and development packages. If you are installing using a binary distribution then you must ensure that the kernel version number of the binary package matches your currently active kernel. You can use `uname' to find out this information: shell> uname -r 2.6.20-gentoo-r6 Once DRBD has been built and installed, you need to edit the `/etc/drbd.conf' file and then run a number of commands to build the block device and set up the replication. Although the steps below are split into those for the primary node and the secondary node, it should be noted that the configuration files for all nodes should be identical, and many of the same steps have to be repeated on each node to enable the DRBD block device. Building from source: To download and install from the source code: 1. Download the source code. 2. Unpack the package: shell> tar zxf drbd-8.3.0.tar.gz 3. Change to the extracted directory, and then run `make' to build the DRBD driver: shell> cd drbd-8.3.0 shell> make 4. Install the kernel driver and commands: shell> make install Binary Installation: * * SUSE Linux Enterprise Server (SLES)* For SUSE, use `yast': shell> yast -i drbd Alternatively: shell> rug install drbd * *Debian* Use `apt-get' to install the modules. You do not need to install any other components. shell> apt-get install drbd8-utils drbd8-module * *Debian 3.1 and 4.0* You must install the `module-assistant' to build the DRBD kernel module, in addition to the DRBD components. shell> apt-get install drbd0.7-utils drbd0.7-module-source \ build-essential module-assistant shell> module-assistant auto-install drbd0.7 * *CentOS* DRBD can be installed using yum: shell> yum install drbd kmod-drbd * *Ubuntu* You must enable the universe component for your preferred Ubuntu mirror in `/etc/apt/sources.list', and then issue these commands: shell> apt-get update shell> apt-get install drbd8-utils drbd8-module-source \ build-essential module-assistant shell> module-assistant auto-install drbd8 * *Gentoo* You can now `emerge' DRBD 0.8.x into your Gentoo installation: root-shell> emerge drbd Once `drbd' has been downloaded and installed, you need to decompress and copy the default configuration file from `/usr/share/doc/drbd-8.0.7/drbd.conf.bz2' into `/etc/drbd.conf'.  File: manual.info, Node: ha-drbd-install-drbd-primary, Next: ha-drbd-install-drbd-secondary, Prev: ha-drbd-install-drbd, Up: ha-drbd-install 15.2.1.3 Setting Up a DRBD Primary Node ....................................... To set up a DRBD primary node you need to configure the DRBD service, create the first DRBD block device and then create a file system on the device so that you can store files and data. The DRBD configuration file `/etc/drbd.conf' defines a number of parameters for your DRBD configuration, including the frequency of updates and block sizes, security information and the definition of the DRBD devices that you want to create. The key elements to configure are the `on' sections which specify the configuration of each node. To follow the configuration, the sequence below shows only the changes from the default `drbd.conf' file. Configurations within the file can be both global or tied to specific resource. 1. Set the synchronization rate between the two nodes. This is the rate at which devices are synchronized in the background after a disk failure, device replacement or during the initial setup. Keep this in check compared to the speed of your network connection. Gigabit Ethernet can support up to 125 MB/second, 100Mbps Ethernet slightly less than a tenth of that (12MBps). If you are using a shared network connection, rather than a dedicated, then gauge accordingly. To set the synchronization rate, edit the `rate' setting within the `syncer' block: syncer { rate 10M; } You may additionally want to set the `al-extents' parameter. The default for this parameter is 257. For more detailed information on synchronization, the effects of the synchronization rate and the effects on network performance, see *Note ha-drbd-performance-syncrate::. 2. Set up some basic authentication. DRBD supports a simple password hash exchange mechanism. This helps to ensure that only those hosts with the same shared secret are able to join the DRBD node group. cram-hmac-alg "sha1"; shared-secret "SHARED-STRING"; 3. Now you must configure the host information. Remember that you must have the node information for the primary and secondary nodes in the `drbd.conf' file on each host. You need to configure the following information for each node: * `device': The path of the logical block device that is created by DRBD. * `disk': The block device that stores the data. * `address': The IP address and port number of the host that holds this DRBD device. * `meta-disk': The location where the metadata about the DRBD device is stored. If you set this to `internal', DRBD uses the physical block device to store the information, by recording the metadata within the last sections of the disk. The exact size depends on the size of the logical block device you have created, but it may involve up to 128MB. A sample configuration for our primary server might look like this: on drbd-one { device /dev/drbd0; disk /dev/hdd1; address 192.168.0.240:8888; meta-disk internal; } The `on' configuration block should be repeated for the secondary node (and any further) nodes: on drbd-two { device /dev/drbd0; disk /dev/hdd1; address 192.168.0.241:8888; meta-disk internal; } The IP address of each `on' block must match the IP address of the corresponding host. Do not set this value to the IP address of the corresponding primary or secondary in each case. 4. Before starting the primary node, create the metadata for the devices: root-shell> drbdadm create-md all 5. You are now ready to start DRBD: root-shell> /etc/init.d/drbd start DRBD should now start and initialize, creating the DRBD devices that you have configured. 6. DRBD creates a standard block device - to make it usable, you must create a file system on the block device just as you would with any standard disk partition. Before you can create the file system, you must mark the new device as the primary device (that is, where the data is written and stored), and initialize the device. Because this is a destructive operation, you must specify the command line option to overwrite the raw data: root-shell> drbdadm -- --overwrite-data-of-peer primary all If you are using a version of DRBD 0.7.x or earlier, then you need to use a different command-line option: root-shell> drbdadm -- --do-what-I-say primary all Now create a file system using your chosen file system type: root-shell> mkfs.ext3 /dev/drbd0 7. You can now mount the file system and if necessary copy files to the mount point: root-shell> mkdir /mnt/drbd root-shell> mount /dev/drbd0 /mnt/drbd root-shell> echo "DRBD Device" >/mnt/drbd/samplefile Your primary node is now ready to use. Next, configure your secondary node or nodes.  File: manual.info, Node: ha-drbd-install-drbd-secondary, Next: ha-drbd-install-drbd-using, Prev: ha-drbd-install-drbd-primary, Up: ha-drbd-install 15.2.1.4 Setting Up a DRBD Secondary Node ......................................... The configuration process for setting up a secondary node is the same as for the primary node, except that you do not have to create the file system on the secondary node device, as this information is automatically transferred from the primary node. To set up a secondary node: 1. Copy the `/etc/drbd.conf' file from your primary node to your secondary node. It should already contain all the information and configuration that you need, since you had to specify the secondary node IP address and other information for the primary node configuration. 2. Create the DRBD metadata on the underlying disk device: root-shell> drbdadm create-md all 3. Start DRBD: root-shell> /etc/init.d/drbd start Once DRBD has started, it starts to copy the data from the primary node to the secondary node. Even with an empty file system this takes some time, since DRBD is copying the block information from a block device, not simply copying the file system data. You can monitor the progress of the copy between the primary and secondary nodes by viewing the output of `/proc/drbd': root-shell> cat /proc/drbd version: 8.0.4 (api:86/proto:86) SVN Revision: 2947 build by root@drbd-one, 2007-07-30 16:43:05 0: cs:SyncSource st:Primary/Secondary ds:UpToDate/Inconsistent C r--- ns:252284 nr:0 dw:0 dr:257280 al:0 bm:15 lo:0 pe:7 ua:157 ap:0 [==>.................] sync'ed: 12.3% (1845088/2097152)K finish: 0:06:06 speed: 4,972 (4,580) K/sec resync: used:1/31 hits:15901 misses:16 starving:0 dirty:0 changed:16 act_log: used:0/257 hits:0 misses:0 starving:0 dirty:0 changed:0 You can monitor the synchronization process by using the `watch' command to run the command at specific intervals: root-shell> watch -n 10 'cat /proc/drbd'  File: manual.info, Node: ha-drbd-install-drbd-using, Next: ha-drbd-install-drbd-management, Prev: ha-drbd-install-drbd-secondary, Up: ha-drbd-install 15.2.1.5 Monitoring DRBD Device ............................... Once the primary and secondary machines are configured and synchronized, you can get the status information about your DRBD device by viewing the output from `/proc/drbd': root-shell> cat /proc/drbd version: 8.0.4 (api:86/proto:86) SVN Revision: 2947 build by root@drbd-one, 2007-07-30 16:43:05 0: cs:Connected st:Primary/Secondary ds:UpToDate/UpToDate C r--- ns:2175704 nr:0 dw:99192 dr:2076641 al:33 bm:128 lo:0 pe:0 ua:0 ap:0 resync: used:0/31 hits:134841 misses:135 starving:0 dirty:0 changed:135 act_log: used:0/257 hits:24765 misses:33 starving:0 dirty:0 changed:33 The first line provides the version/revision and build information. The second line starts the detailed status information for an individual resource. The individual field headings are as follows: * cs: connection state * st: node state (local/remote) * ld: local data consistency * ds: data consistency * ns: network send * nr: network receive * dw: disk write * dr: disk read * pe: pending (waiting for ack) * ua: unack'd (still need to send ack) * al: access log write count In the previous example, the information shown indicates that the nodes are connected, the local node is the primary (because it is listed first), and the local and remote data is up to date with each other. The remainder of the information is statistical data about the device, and the data exchanged that kept the information up to date. You can also get the status information for DRBD by using the startup script with the `status' option: root-shell> /etc/init.d/drbd status * status: started * drbd driver loaded OK; device status: ... [ ok ] version: 8.3.0 (api:88/proto:86-89) GIT-hash: 9ba8b93e24d842f0dd3fb1f9b90e8348ddb95829 build by root@gentoo1.vmbear, 2009-03-14 23:00:06 0: cs:Connected ro:Secondary/Secondary ds:UpToDate/UpToDate C r--- ns:0 nr:0 dw:0 dr:8385604 al:0 bm:0 lo:0 pe:0 ua:0 ap:0 ep:1 wo:b oos:0 The information and statistics are the same.  File: manual.info, Node: ha-drbd-install-drbd-management, Next: ha-drbd-install-drbd-othercfg, Prev: ha-drbd-install-drbd-using, Up: ha-drbd-install 15.2.1.6 Managing your DRBD Installation ........................................ For administration, the main command is `drbdadm'. There are a number of commands supported by this tool the control the connectivity and status of the DRBD devices. *Note*: For convenience, a bash completion script is available that provides tab completion for options to `drbdadm'. The file `drbdadm.bash_completion' can be found within the standard DRBD source package within the `scripts' directory. To enable, copy the file to `/etc/bash_completion.d/drbdadm'. You can load it manually by using: shell> source /etc/bash_completion.d/drbdadm The most common commands are those to set the primary/secondary status of the local device. You can manually set this information for a number of reasons, including when you want to check the physical status of the secondary device (since you cannot mount a DRBD device in primary mode), or when you are temporarily moving the responsibility of keeping the data in check to a different machine (for example, during an upgrade or physical move of the normal primary node). You can set state of all local device to be the primary using this command: root-shell> drbdadm primary all Or switch the local device to be the secondary using: root-shell> drbdadm secondary all To change only a single DRBD resource, specify the resource name instead of `all'. You can temporarily disconnect the DRBD nodes: root-shell> drbdadm disconnect all Reconnect them using `connect': root-shell> drbdadm connect all For other commands and help with `drbdadm' see the DRBD documentation.  File: manual.info, Node: ha-drbd-install-drbd-othercfg, Prev: ha-drbd-install-drbd-management, Up: ha-drbd-install 15.2.1.7 Additional DRBD Configuration Options .............................................. Additional options you may want to configure: * `protocol': Specifies the level of consistency to be used when information is written to the block device. The option is similar in principle to the `innodb_flush_log_at_trx_commit' option within MySQL. Three levels are supported: * `A': Data is considered written when the information reaches the TCP send buffer and the local physical disk. There is no guarantee that the data has been written to the remote server or the remote physical disk. * `B': Data is considered written when the data has reached the local disk and the remote node's network buffer. The data has reached the remote server, but there is no guarantee it has reached the remote server's physical disk. * `C': Data is considered written when the data has reached the local disk and the remote node's physical disk. The preferred and recommended protocol is C, as it is the only protocol which ensures the consistency of the local and remote physical storage. * `size': If you do not want to use the entire partition space with your DRBD block device then you can specify the size of the DRBD device to be created. The size specification can include a quantifier. For example, to set the maximum size of the DRBD partition to 1GB you would use: size 1G; With the configuration file suitably configured and ready to use, you now need to populate the lower-level device with the metadata information, and then start the DRBD service.  File: manual.info, Node: ha-drbd-install-mysql, Next: ha-drbd-performance, Prev: ha-drbd-install, Up: ha-drbd 15.2.2 Configuring MySQL for DRBD --------------------------------- Once you have configured DRBD and have an active DRBD device and file system, you can configure MySQL to use the chosen device to store the MySQL data. When performing a new installation of MySQL, you can either select to install MySQL entirely onto the DRBD device, or just configure the data directory to be located on the new file system. In either case, the files and installation must take place on the primary node, because that is the only DRBD node on which you can mount the DRBD device file system as read/write. Store the following files and information on your DRBD device: * MySQL data files, including the binary log, and InnoDB data files. * MySQL configuration file (`my.cnf'). To set up MySQL to use your new DRBD device and file system: 1. If you are migrating an existing MySQL installation, stop MySQL: shell> mysqladmin shutdown 2. Copy the `my.cnf' onto the DRBD device. If you are not already using a configuration file, copy one of the sample configuration files from the MySQL distribution. root-shell> mkdir /mnt/drbd/mysql root-shell> cp /etc/my.cnf /mnt/drbd/mysql 3. Copy your MySQL data directory to the DRBD device and mounted file system. root-shell> cp -R /var/lib/mysql /drbd/mysql/data 4. Edit the configuration file to reflect the change of directory by setting the value of the `datadir' option. If you have not already enabled the binary log, also set the value of the `log-bin' option. datadir = /drbd/mysql/data log-bin = mysql-bin 5. Create a symbolic link from `/etc/my.cnf' to the new configuration file on the DRBD device file system. root-shell> ln -s /drbd/mysql/my.cnf /etc/my.cnf 6. Now start MySQL and check that the data that you copied to the DRBD device file system is present. root-shell> /etc/init.d/mysql start Your MySQL data should now be located on the file system running on your DRBD device. The data is physically stored on the underlying device that you configured for the DRBD device. Meanwhile, the content of your MySQL databases is copied to the secondary DRBD node. Note that you cannot access the information on your secondary node, as a DRBD device working in secondary mode is not available for use.  File: manual.info, Node: ha-drbd-performance, Prev: ha-drbd-install-mysql, Up: ha-drbd 15.2.3 Optimizing Performance and Reliability --------------------------------------------- * Menu: * ha-drbd-performance-bonded:: Using Bonded Ethernet Network Interfaces * ha-drbd-performance-syncrate:: Optimizing the Synchronization Rate Because of the nature of the DRBD system, the critical requirements are for a very fast exchange of the information between the two hosts. To ensure that your DRBD setup is available to switch over in the event of a failure as quickly as possible, you must transfer the information between the two hosts using the fastest method available. Typically, a dedicated network circuit should be used for exchanging DRBD data between the two hosts. Use a separate, additional, network interface for your standard network connection. For an example of this layout, see *Note ha-drbd-performance-sepinterface::. FIGURE GOES HERE: DRBD Architecture Using Separate Network Interfaces The dedicated DRBD network interfaces should be configured to use a nonrouted TCP/IP network configuration. For example, you might want to set the primary to use 192.168.0.1 and the secondary 192.168.0.2. These networks and IP addresses should not be part of normal network subnet. *Note*: The preferred setup, whenever possible, is to use a direct cable connection (using a crossover cable with Ethernet, for example) between the two machines. This eliminates the risk of loss of connectivity due to switch failures.  File: manual.info, Node: ha-drbd-performance-bonded, Next: ha-drbd-performance-syncrate, Prev: ha-drbd-performance, Up: ha-drbd-performance 15.2.3.1 Using Bonded Ethernet Network Interfaces ................................................. For a set-up where there is a high-throughput of information being written, you may want to use bonded network interfaces. This is where you combine the connectivity of more than one network port, increasing the throughput linearly according to the number of bonded connections. Bonding also provides an additional benefit in that with multiple network interfaces effectively supporting the same communications channel, a fault within a single network interface in a bonded group does not stop communication. For example, imagine you have a bonded setup with four network interfaces providing a single interface channel between two DRBD servers. If one network interface fails, communication can continue on the other three without interruption, although at a lower speed. To enable bonded connections you must enable bonding within the kernel. You then need to configure the module to specify the bonded devices and then configure each new bonded device just as you would a standard network device: * To configure the bonded devices, edit the `/etc/modprobe.conf' file (Red Hat) or add a file to the `/etc/modprobe.d' directory. In each case, you define the parameters for the kernel module. First, specify each bonding device: alias bond0 bonding You can then configure additional parameters for the kernel module. Typical parameters are the `mode' option and the `miimon' option. The `mode' option specifies how the network interfaces are used. The default setting is 0, which means that each network interface is used in a round-robin fashion (this supports aggregation and fault tolerance). Using setting 1 sets the bonding mode to active-backup. This means that only one network interface is used as a time, but that the link automatically fails over to a new interface if the primary interface fails. This settings only supports fault-tolerance. The `miimon' option enables the MII link monitoring. A positive value greater than zero indicates the monitoring frequency in milliseconds for checking each slave network interface that is configured as part of the bonded interface. A typical value is 100. You set th options within the module parameter file, and you must set the options for each bonded device individually: options bond0 miimon=100 mode=1 * Reboot your server to enable the bonded devices. * Configure the network device parameters. There are two parts to this, you need to setup the bonded device configuration, and then configure the original network interfaces as 'slaves' of the new bonded interface. * For Red Hat Linux: Edit the configuration file for the bonded device. For device `bond0' this would be `/etc/sysconfig/network-scripts/ifcfg-bond0': DEVICE=bond0 BOOTPROTO=none ONBOOT=yes GATEWAY=192.168.0.254 NETWORK=192.168.0.0 NETMASK=255.255.255.0 IPADDR=192.168.0.1 USERCTL=no Then for each network interface that you want to be part of the bonded device, configure the interface as a slave to the 'master' bond. For example, the configuration of `eth0' in `/etc/sysconfig/network-scripts/ifcfg-eth0' might look like this:: DEVICE=eth0 BOOTPROTO=none HWADDR=00:11:22:33:44:55 ONBOOT=yes TYPE=Ethernet MASTER=bond0 SLAVE=yes * For Debian Linux: Edit the `/etc/iftab' file and configure the logical name and MAC address for each devices. For example: eth0 mac 00:11:22:33:44:55 Now you need to set the configuration of the devices in `/etc/network/interfaces': auto bond0 iface bond0 inet static address 192.168.0.1 netmask 255.255.255.0 network 192.168.0.0 gateway 192.168.0.254 up /sbin/ifenslave bond0 eth0 up /sbin/ifenslave bond0 eth1 * For Gentoo: Use `emerge' to add the `net-misc/ifenslave' package to your system. Edit the `/etc/conf.d/net' file and specify the network interface slaves in a bond, the dependencies and then the configuration for the bond itself. A sample configuration might look like this: slaves_bond0="eth0 eth1 eth2" config_bond0=( "192.168.0.1 netmask 255.255.255.0" ) depend_bond0() { need net.eth0 net.eth1 net.eth2 } Then make sure that you add the new network interface to list of interfaces configured during boot: root-shell> rc-update add default net.bond0 Once the bonded devices are configured, reboot your systems. You can monitor the status of a bonded connection using the `/proc' file system: root-shell> cat /proc/net/bonding/bond0 Bonding Mode: fault-tolerance (active-backup) Primary Slave: None Currently Active Slave: eth1 MII Status: up MII Polling Interval (ms): 100 Up Delay (ms): 200 Down Delay (ms): 200 Slave Interface: eth1 MII Status: up Link Failure Count: 0 Permanent HW addr: 00:11:22:33:44:55 Slave Interface: eth2 MII Status: up Link Failure Count: 0 Permanent HW addr: 00:11:22:33:44:56  File: manual.info, Node: ha-drbd-performance-syncrate, Prev: ha-drbd-performance-bonded, Up: ha-drbd-performance 15.2.3.2 Optimizing the Synchronization Rate ............................................ The `syncer rate' configuration parameter should be configured with care as the synchronization rate can have a significant effect on the performance of the DRBD setup in the event of a node or disk failure where the information is being synchronized from the Primary to the Secondary node. In DRBD, there are two distinct ways of data being transferred between peer nodes: * _Replication_ refers to the transfer of modified blocks being transferred from the primary to the secondary node. This happens automatically when the block is modified on the primary node, and the replication process uses whatever bandwidth is available over the replication link. The replication process cannot be throttled, because you want to transfer of the block information to happen as quickly as possible during normal operation. * _Synchronization_ refers to the process of bringing peers back in sync after some sort of outage, due to manual intervention, node failure, disk swap, or the initial setup. Synchronization is limited to the `syncer rate' configured for the DRBD device. Both replication and synchronization can take place at the same time. For example, the block devices can be synchronized while they are actively being used by the primary node. Any I/O that updates on the primary node automatically triggers replication of the modified block. In the event of a failure within an HA environment, it is highly likely that synchronization and replication will take place at the same time. Unfortunately, if the synchronization rate is set too high, then the synchronization process uses up all the available network bandwidth between the primary and secondary nodes. In turn, the bandwidth available for replication of changed blocks is zero, which stalls replication and blocks I/O, and ultimately the application fails or degrades. To avoid enabling the `syncer rate' to consume the available network bandwidth and prevent the replication of changed blocks, set the `syncer rate' to less than the maximum network bandwidth. Avoid setting the sync rate to more than 30% of the maximum bandwidth available to your device and network bandwidth. For example, if your network bandwidth is based on Gigabit ethernet, you should achieve 110MB/s. Assuming your disk interface is capable of handling data at 110MB/s or more, then the sync rate should be configured as `33M' (33MB/s). If your disk system works at a rate lower than your network interface, use 30% of your disk interface speed. Depending on the application, you may wish to limit the synchronization rate. For example, on a busy server you may wish to configure a significantly slower synchronization rate to ensure the replication rate is not affected. The `al-extents' parameter controls the number of 4MB blocks of the underlying disk that can be written to at the same time. Increasing this parameter lowers the frequency of the metadata transactions required to log the changes to the DRBD device, which in turn lowers the number of interruptions in your I/O stream when synchronizing changes. This can lower the latency of changes to the DRBD device. However, if a crash occurs on your primary, then all of the blocks in the activity log (that is, the number of `al-extents' blocks) must be completely resynchronized before replication can continue.  File: manual.info, Node: ha-heartbeat, Next: ha-vm, Prev: ha-drbd, Up: ha-overview 15.3 Using Linux HA Heartbeat ============================= * Menu: * ha-heartbeat-config:: Heartbeat Configuration * ha-heartbeat-drbd:: Using Heartbeat with MySQL and DRBD * ha-heartbeat-drbd-dopd:: Using Heartbeat with DRBD and `dopd' * ha-heartbeat-errors:: Dealing with System Level Errors The Heartbeat program provides a basis for verifying the availability of resources on one or more systems within a cluster. In this context a resource includes MySQL, the file systems on which the MySQL data is being stored and, if you are using DRBD, the DRBD device being used for the file system. Heartbeat also manages a virtual IP address, and the virtual IP address should be used for all communication to the MySQL instance. A cluster within the context of Heartbeat is defined as two computers notionally providing the same service. By definition, each computer in the cluster is physically capable of providing the same services as all the others in the cluster. However, because the cluster is designed for high-availability, only one of the servers is actively providing the service at any one time. Each additional server within the cluster is a `hot-spare' that can be brought into service in the event of a failure of the master, its next connectivity or the connectivity of the network in general. The basics of Heartbeat are very simple. Within the Heartbeat cluster (see *Note ha-heartbeat-overview::, each machine sends a 'heartbeat' signal to the other hosts in the cluster. The other cluster nodes monitor this heartbeat. The heartbeat can be transmitted over many different systems, including shared network devices, dedicated network interfaces and serial connections. Failure to get a heartbeat from a node is treated as failure of the node. Although we do not know the reason for the failure (it could be an OS failure, a hardware failure in the server, or a failure in the network switch), it is safe to assume that if no heartbeat is produced there is a fault. FIGURE GOES HERE: Heartbeat Architecture In addition to checking the heartbeat from the server, the system can also check the connectivity (using `ping') to another host on the network, such as the network router. This enables Heartbeat to detect a failure of communication between a server and the router (and therefore failure of the server, since it is no longer capable of providing the necessary service), even if the heartbeat between the servers in the clusters is working fine. In the event of a failure, the resources on the failed host are disabled, and the resources on one of the replacement hosts is enabled instead. In addition, the Virtual IP address for the cluster is redirected to the new host in place of the failed device. When used with MySQL and DRBD, the MySQL data is replicated from the master to the slave using the DRBD device, but MySQL is only running on the master. When the master fails, the slave switches the DRBD devices to be primary, the file systems on those devices are mounted, and MySQL is started. The original master (if still available) has its resources disabled, which means shutting down MySQL and unmounting the file systems and switching the DRBD device to secondary.  File: manual.info, Node: ha-heartbeat-config, Next: ha-heartbeat-drbd, Prev: ha-heartbeat, Up: ha-heartbeat 15.3.1 Heartbeat Configuration ------------------------------ Heartbeat configuration requires three files located in `/etc/ha.d'. The `ha.cf' contains the main heartbeat configuration, including the list of the nodes and times for identifying failures. `haresources' contains the list of resources to be managed within the cluster. The `authkeys' file contains the security information for the cluster. The contents of these files should be identical on each host within the Heartbeat cluster. It is important that you keep these files in sync across all the hosts. Any changes in the information on one host should be copied to the all the others. For these examples n example of the `ha.cf' file is shown below: logfacility local0 keepalive 500ms deadtime 10 warntime 5 initdead 30 mcast bond0 225.0.0.1 694 2 0 mcast bond1 225.0.0.2 694 1 0 auto_failback off node drbd1 node drbd2 The individual lines in the file can be identified as follows: * `logfacility': Sets the logging, in this case setting the logging to use `syslog'. * `keepalive': Defines how frequently the heartbeat signal is sent to the other hosts. * `deadtime'-- the delay in seconds before other hosts in the cluster are considered 'dead' (failed). * `warntime': The delay in seconds before a warning is written to the log that a node cannot be contacted. * `initdead': The period in seconds to wait during system startup before the other host is considered to be down. * `mcast': Defines a method for sending a heartbeat signal. In the above example, a multicast network address is being used over a bonded network device. If you have multiple clusters then the multicast address for each cluster should be unique on your network. Other choices for the heartbeat exchange exist, including a serial connection. If you are using multiple network interfaces (for example, one interface for your server connectivity and a secondary or bonded interface for your DRBD data exchange), use both interfaces for your heartbeat connection. This decreases the chance of a transient failure causing a invalid failure event. * `auto_failback': Sets whether the original (preferred) server should be enabled again if it becomes available. Switching this to `on' may cause problems if the preferred went offline and then comes back on line again. If the DRBD device has not been synced properly, or if the problem with the original server happens again you may end up with two different datasets on the two servers, or with a continually changing environment where the two servers flip-flop as the preferred server reboots and then starts again. * `node': Sets the nodes within the Heartbeat cluster group. There should be one `node' for each server. An optional additional set of information provides the configuration for a ping test that checks the connectivity to another host. Use this to ensure that you have connectivity on the public interface for your servers, so the ping test should be to a reliable host such as a router or switch. The additional lines specify the destination machine for the `ping', which should be specified as an IP address, rather than a host name; the command to run when a failure occurs, the authority for the failure and the timeout before an nonresponse triggers a failure. A sample configure is shown below: ping 10.0.0.1 respawn hacluster /usr/lib64/heartbeat/ipfail apiauth ipfail gid=haclient uid=hacluster deadping 5 In the above example, the `ipfail' command, which is part of the Heartbeat solution, is called on a failure and 'fakes' a fault on the currently active server. You need to configure the user and group ID under which the command is executed (using the `apiauth'). The failure is triggered after 5 seconds. *Note*: The `deadping' value must be less than the `deadtime' value. The `authkeys' file holds the authorization information for the Heartbeat cluster. The authorization relies on a single unique 'key' that is used to verify the two machines in the Heartbeat cluster. The file is used only to confirm that the two machines are in the same cluster and is used to ensure that the multiple clusters can co-exist within the same network.  File: manual.info, Node: ha-heartbeat-drbd, Next: ha-heartbeat-drbd-dopd, Prev: ha-heartbeat-config, Up: ha-heartbeat 15.3.2 Using Heartbeat with MySQL and DRBD ------------------------------------------ To use Heartbeat in combination with MySQL, use DRBD (see *Note ha-drbd::) or another solution that enables sharing the MySQL database files in event of a system failure. In these examples, DRBD is used as the data sharing solution. Heartbeat manages the configuration of different resources to manage the switching between two servers in the event of a failure. The resource configuration defines the individual services that should be brought up (or taken down) in the event of a failure. The `haresources' file within `/etc/ha.d' defines the resources that should be managed, and the individual resource mentioned in this file in turn relates to scripts located within `/etc/ha.d/resource.d'. The resource definition is defined all on one line: drbd1 drbddisk Filesystem::/dev/drbd0::/drbd::ext3 mysql 10.0.0.100 The line is notionally split by whitespace. The first entry (`drbd1') is the name of the preferred host; that is the server that is normally responsible for handling the service. The last field is virtual IP address or name that should be used to share the service. This is the IP address that should be used to connect to the MySQL server. It is automatically allocated to the server that is active when Heartbeat starts. The remaining fields between these two fields define the resources that should be managed. Each Field should contain the name of the resource (and each name should refer to a script within `/etc/ha.d/resource.d'). In the event of a failure, these resources are started on the backup server by calling the corresponding script (with a single argument, `start'), in order from left to right. If there are additional arguments to the script, you can use a double colon to separate each additional argument. In the above example, we manage the following resources: * `drbddisk': The DRBD resource script, this switches the DRBD disk on the secondary host into primary mode, making the device read/write. * `Filesystem': Manages the Filesystem resource. In this case we have supplied additional arguments to specify the DRBD device, mount point and file system type. When executed this should mount the specified file system. * `mysql': Manages the MySQL instances and starts the MySQL server. Copy the `mysql.resource' file from the `support-files' directory from any MySQL release into the `/etc/ha.d/resources.d' directory. If this file is not available in your distribution, you can use the following as the contents of the `/etc/ha.d/resource.d/mysql.resource' file: #!/bin/bash # # This script is inteded to be used as resource script by heartbeat # # Mar 2006 by Monty Taylor # ### . /etc/ha.d/shellfuncs case "$1" in start) res=`/etc/init.d/mysql start` ret=$? ha_log $res exit $ret ;; stop) res=`/etc/init.d/mysql stop` ret=$? ha_log $res exit $ret ;; status) if [[ `ps -ef | grep '[m]ysqld'` > 1 ]] ; then echo "running" else echo "stopped" fi ;; *) echo "Usage: mysql {start|stop|status}" exit 1 ;; esac exit 0 If you want to be notified of the failure by email, you can add another line to the `haresources' file with the address for warnings and the warning text: MailTo::youremail@address.com::DRBDFailure With the Heartbeat configuration in place, copy the `haresources', `authkeys' and `ha.cf' files from your primary and secondary servers to make sure that the configuration is identical. Then start the Heartbeat service, either by calling `/etc/init.d/heartbeat start' or by rebooting both primary and secondary servers. You can test the configuration by running a manual failover, connect to the primary node and run: root-shell> /usr/lib64/heartbeat/hb_standby This causes the current node to relinquish its resources cleanly to the other node.  File: manual.info, Node: ha-heartbeat-drbd-dopd, Next: ha-heartbeat-errors, Prev: ha-heartbeat-drbd, Up: ha-heartbeat 15.3.3 Using Heartbeat with DRBD and `dopd' ------------------------------------------- As a further extension to using DRBD and Heartbeat together, you can enable `dopd'. The `dopd' daemon handles the situation where a DRBD node is out of date compared to the master and prevents the slave from being promoted to master in the event of a failure. This stops a situation where you have two machines that have been masters ending up different data on the underlying device. For example, imagine that you have a two server DRBD setup, master and slave. If the DRBD connectivity between master and slave fails, then the slave is out of the sync with the master. If Heartbeat identifies a connectivity issue for master and then switches over to the slave, the slave DRBD device is promoted to the primary device, even though the data on the slave and the master is not in synchronization. In this situation, with `dopd' enabled, the connectivity failure between the master and slave would be identified and the metadata on the slave would be set to `Outdated'. Heartbeat refuses to switch over to the slave even if the master failed. In a dual-host solution this would effectively render the cluster out of action, as there is no additional fail over server. In an HA cluster with three or more servers, control would be passed to the slave that has an up to date version of the DRBD device data. To enable `dopd', you need to modify the Heartbeat configuration and specify `dopd' as part of the commands executed during the monitoring process. Add the following lines to your `ha.cf' file: respawn hacluster /usr/lib/heartbeat/dopd apiauth dopd gid=haclient uid=hacluster Make sure you make the same modification on both your primary and secondary nodes. Reload the Heartbeat configuration: root-shell> /etc/init.d/heartbeat reload Modify your DRBD configuration by configuration the `outdate-peer' option. Add the configuration line into the `common' section of `/etc/drbd.conf' on both hosts. An example of the full block is shown below: common { handlers { outdate-peer "/usr/lib/heartbeat/drbd-peer-outdater"; } } Finally, set the `fencing' option on your DRBD configured resources: resource my-resource { disk { fencing resource-only; } } Now reload your DRBD configuration: root-shell> drbdadmin adjust all You can test the system by unplugging your DRBD link and monitoring the output from `/proc/drbd'.  File: manual.info, Node: ha-heartbeat-errors, Prev: ha-heartbeat-drbd-dopd, Up: ha-heartbeat 15.3.4 Dealing with System Level Errors --------------------------------------- Because a kernel panic or oops may indicate potential problem with your server, configure your server to remove itself from the cluster in the event of a problem. Typically on a kernel panic, your system automatically triggers a hard reboot. For a kernel oops, a reboot may not happen automatically, but the issue that caused that oops may still lead to potential problems. You can force a reboot by setting the `kernel.panic' and `kernel.panic_on_oops' parameters of the kernel control file `/etc/sysctl.conf'. For example: kernel.panic_on_oops = 1 kernel.panic = 1 You can also set these parameters during runtime by using the `sysctl' command. You can either specify the parameters on the command line: shell> sysctl -w kernel.panic=1 Or you can edit your `sysctl.conf' file and then reload the configuration information: shell> sysctl -p Setting both these parameters to a positive value (representing the number of seconds to wait before rebooting), causes the system to reboot. Your second heartbeat node should then detect that the server is down and then switch over to the failover host.  File: manual.info, Node: ha-vm, Next: ha-zfs-replication, Prev: ha-heartbeat, Up: ha-overview 15.4 Using MySQL within an Amazon EC2 Instance ============================================== * Menu: * ha-vm-aws-setup:: Setting Up MySQL on an EC2 AMI * ha-vm-aws-instance:: EC2 Instance Limitations * ha-vm-aws-deploy:: Deploying a MySQL Database Using EC2 The Amazon Elastic Compute Cloud (EC2) service provides virtual servers that you can build and deploy to run a variety of different applications and services, including MySQL. The EC2 service is based around the Xen framework, supporting x86, Linux based, platforms with individual instances of a virtual machine referred to as an Amazon Machine Image (AMI). You have complete (root) access to the AMI instance that you create, enabling you to configure and install your AMI in any way you choose. To use EC2, you create an AMI based on the configuration and applications that you want to use and upload the AMI to the Amazon Simple Storage Service (S3). From the S3 resource, you can deploy one or more copies of the AMI to run as an instance within the EC2 environment. The EC2 environment provides management and control of the instance and contextual information about the instance while it is running. Because you can create and control the AMI, the configuration, and the applications, you can deploy and create any environment you choose. This includes a basic MySQL server in addition to more extensive replication, HA and scalability scenarios that enable you to take advantage of the EC2 environment, and the ability to deploy additional instances as the demand for your MySQL services and applications grow. To aid the deployment and distribution of work, three different Amazon EC2 instances are available, small (identified as `m1.small'), large (`m1.large') and extra large (`m1.xlarge'). The different types provide different levels of computing power measured in EC2 computer units (ECU). A summary of the different instance configurations is shown here. Small Large Extra Large Platform 32-bit 64-bit 64-bit CPU cores 1 2 4 ECUs 1 4 8 RAM 1.7GB 7.5GB 15GB Storage 150GB 840GB 1680GB I/O Performance Medium High High The typical model for deploying and using MySQL within the EC2 environment is to create a basic AMI that you can use to hold your database data and application. Once the basic environment for your database and application has been created you can then choose to deploy the AMI to a suitable instance. Here the flexibility of having an AMI that can be re-deployed from the small to the large or extra large EC2 instance makes it easy to upgrade the hardware environment without rebuilding your application or database stack. To get started with MySQL on EC2, including information on how to set up and install MySQL within an EC2 installation and how to port and migrate your data to the running instance, see *Note ha-vm-aws-setup::. For tips and advice on how to create a scalable EC2 environment using MySQL, including guides on setting up replication, see *Note ha-vm-aws-deploy::.  File: manual.info, Node: ha-vm-aws-setup, Next: ha-vm-aws-instance, Prev: ha-vm, Up: ha-vm 15.4.1 Setting Up MySQL on an EC2 AMI ------------------------------------- There are many different ways of setting up an EC2 AMI with MySQL, including using any of the pre-configured AMIs supplied by Amazon. The default _Getting Started_ AMI provided by Amazon uses Fedora Core 4, and you can install MySQL by using `yum': shell> yum install mysql This installs both the MySQL server and the Perl DBD::mysql driver for the Perl DBI API. Alternatively, you can use one of the AMIs that include MySQL within the standard installation. Finally, you can also install a standard version of MySQL downloaded from the MySQL Web site. The installation process and instructions are identical to any other installation of MySQL on Linux. See *Note installing::. The standard configuration for MySQL places the data files in the default location, `/var/lib/mysql'. The default data directory on an EC2 instance is `/mnt' (although on the large and extra large instance you can alter this configuration). You must edit `/etc/my.cnf' to set the `datadir' option to point to the larger storage area. *Important*: The first time you use the main storage location within an EC2 instance it needs to be initialized. The initialization process starts automatically the first time you write to the device. You can start using the device right away, but the write performance of the new device is significantly lower on the initial writes until the initialization process has finished. To avoid this problem when setting up a new instance, you should start the initialization process before populating your MySQL database. One way to do this is to use `dd' to write to the file system: root-shell> dd if=/dev/zero of=initialize bs=1024M count=50 The preceding creates a 50GB on the file system and starts the initialization process. Delete the file once the process has finished. The initialization process can be time-consuming. On the small instance, initialization takes between two and three hours. For the large and extra large drives, the initialization can be 10 or 20 hours, respectively. In addition to configuring the correct storage location for your MySQL data files, also consider setting the following other settings in your instance before you save the instance configuration for deployment: * Set the MySQL server ID, so that when you use it for replication, the ID information is set correctly. * Enabling binary logging, so that replication can be initialized without starting and stopping the server. * Set the caching and memory parameters for your storage engines. There are no limitations or restrictions on what storage engines you use in your EC2 environment. Choose a configuration, possibly using one of the standard configurations provided with MySQL appropriate for the instance on which you expect to deploy. The large and extra large instances have RAM that can be dedicated to caching. Be aware that if you choose to install `memcached' on the servers as part of your application stack you must ensure there is enough memory for both MySQL and `memcached'. Once you have configured your AMI with MySQL and the rest of your application stack, save the AMI so that you can deploy and reuse the instance. Once you have your application stack configured in an AMI, populating your MySQL database with data should be performed by creating a dump of your database using `mysqldump', transferring the dump to the EC2 instance, and then reloading the information into the EC2 instance database. Before using your instance with your application in a production situation, be aware of the limitations of the EC2 instance environment. See *Note ha-vm-aws-instance::. To begin using your MySQL AMI, consult the notes on deployment. See *Note ha-vm-aws-deploy::.  File: manual.info, Node: ha-vm-aws-instance, Next: ha-vm-aws-deploy, Prev: ha-vm-aws-setup, Up: ha-vm 15.4.2 EC2 Instance Limitations ------------------------------- Be aware of the following limitations of the EC2 instances before deploying your applications. Although these shouldn't affect your ability to deploy within the Amazon EC2 environment, they may alter the way you setup and configure your environment to support your application. * Data stored within instances is not persistent. If you create an instance and populate the instance with data, then the data only remains in place while the machine is running, and does not survive a reboot. If you shut down the instance, any data it contained is lost. To ensure that you do not lose information, take regular backups using *Note `mysqldump': mysqldump. If the data being stored is critical, consider using replication to keep a `live' backup of your data in the event of a failure. When creating a backup, write the data to the Amazon S3 service to avoid the transfer charges applied when copying data offsite. * EC2 instances are not persistent. If the hardware on which an instance is running fails, the instance is shut down. This can lead to loss of data or service. * If you want to use replication with your EC2 instances to a non-EC2 environment, be aware of the transfer costs to and from the EC2 service. Data transfer between different EC2 instances is free, so using replication within the EC2 environment does not incur additional charges. * Certain HA features are either not directly supported, or have limiting factors or problems that may reduce their utility. For example, using DRBD or MySQL Cluster may not work. The default storage configuration is also not redundant. You can use software-based RAID to improve redundancy, but this implies a further performance hit.  File: manual.info, Node: ha-vm-aws-deploy, Prev: ha-vm-aws-instance, Up: ha-vm 15.4.3 Deploying a MySQL Database Using EC2 ------------------------------------------- Because you cannot guarantee the uptime and availability of your EC2 instances, when deploying MySQL within the EC2 environment, use an approach that enables you to easily distribute work among your EC2 instances. There are a number of ways of doing this. Using sharding techniques, where you split the application across multiple servers dedicating specific blocks of your dataset and users to different servers is an effective way of doing this. As a general rule, it is easier to create more EC2 instances to support more users than to upgrade the instance to a larger machine. The EC2 architecture works best when you treat the EC2 instances as temporary, cache-based solutions, rather than as a long-term, high availability solution. In addition to using multiple machines, take advantage of other services, such as `memcached' to provide additional caching for your application to help reduce the load on the MySQL server so that it can concentrate on writes. On the large and extra large instances within EC2, the RAM available can provide a large memory cache for data. Most types of scale-out topology that you would use with your own hardware can be used and applied within the EC2 environment. However, use the limitations and advice already given to ensure that any potential failures do not lose you any data. Also, because the relative power of each EC2 instance is so low, be prepared to alter your application to use sharding and add further EC2 instances to improve the performance of your application. For example, take the typical scale-out environment shown following, where a single master replicates to one or more slaves (three in this example), with a web server running on each replication slave. Typical standard scale-out structure You can reproduce this structure completely within the EC2 environment, using an EC2 instance for the master, and one instance for each of the web and MySQL slave servers. *Note*: Within the EC2 environment, internal (private) IP addresses used by the EC2 instances are constant. Always use these internal addresses and names when communicating between instances. Only use public IP addresses when communicating with the outside world - for example, when publicizing your application. To ensure reliability of your database, add at least one replication slave dedicated to providing an active backup and storage to the Amazon S3 facility. You can see an example of this in the following topology. Typical standard scale-out structure with backup using EC2 *Using `memcached'* within your EC2 instances should provide better performance. The large and extra large instances have a significant amount of RAM. To use `memcached' in your application, when loading information from the database, first check whether the item exists in the cache. If the data you are looking for exists in the cache, use it. If not, reload the data from the database and populate the cache. *Sharding* divides up data in your entire database by allocating individual machines or machine groups to provide a unique set of data according to an appropriate group. For example, you might put all users with a surname ending in the letters A-D onto a single server. When a user connects to the application and their surname is known, queries can be redirected to the appropriate MySQL server. When using sharding with EC2, separate the web server and MySQL server into separate EC2 instances, and then apply the sharding decision logic into your application. Once you know which MySQL server you should be using for accessing the data you then distribute queries to the appropriate server. You can see a sample of this in the following illustration. Using sharding in EC2 to spread the load *Warning*: With sharding and EC2, be careful that the potential for failure of an instance does not affect your application. If the EC2 instance that provides the MySQL server for a particular shard fails, then all of the data on that shard becomes unavailable.  File: manual.info, Node: ha-zfs-replication, Next: ha-memcached, Prev: ha-vm, Up: ha-overview 15.5 Using ZFS Replication ========================== * Menu: * ha-zfs-config:: Using ZFS for File System Replication * ha-zfs-mysql:: Configuring MySQL for ZFS Replication * ha-zfs-mysql-recovery:: Handling MySQL Recovery with ZFS To support high availability environments, providing an instant copy of the information on both the currently active machine and the hot backup is a critical part of the HA solution. There are many solutions to this problem, including *Note replication:: and *Note ha-drbd::. The ZFS file system provides functionality that enables you to create a snapshot of the file system contents and to then transfer the snapshot to another machine and extract the snapshot to recreate the file system. You can create a snapshot at any time, and you can create as many snapshots as you like. By continually creating, transferring and restoring snapshots you can provide synchronization between one ore more machines in a fashion similar to DRBD. To understand the replication solution within ZFS, you must first understand the ZFS environment. Below is a simple Solaris system running with a single ZFS pool, mounted at `/scratchpool': Filesystem size used avail capacity Mounted on /dev/dsk/c0d0s0 4.6G 3.7G 886M 82% / /devices 0K 0K 0K 0% /devices ctfs 0K 0K 0K 0% /system/contract proc 0K 0K 0K 0% /proc mnttab 0K 0K 0K 0% /etc/mnttab swap 1.4G 892K 1.4G 1% /etc/svc/volatile objfs 0K 0K 0K 0% /system/object /usr/lib/libc/libc_hwcap1.so.1 4.6G 3.7G 886M 82% /lib/libc.so.1 fd 0K 0K 0K 0% /dev/fd swap 1.4G 40K 1.4G 1% /tmp swap 1.4G 28K 1.4G 1% /var/run /dev/dsk/c0d0s7 26G 913M 25G 4% /export/home scratchpool 16G 24K 16G 1% /scratchpool The MySQL data is stored in a directory on `/scratchpool'. To help demonstrate some of the basic replication functionality, there are also other items stored in `/scratchpool' as well: total 17 drwxr-xr-x 31 root bin 50 Jul 21 07:32 DTT/ drwxr-xr-x 4 root bin 5 Jul 21 07:32 SUNWmlib/ drwxr-xr-x 14 root sys 16 Nov 5 09:56 SUNWspro/ drwxrwxrwx 19 1000 1000 40 Nov 6 19:16 emacs-22.1/ To create a snapshot of the file system, you use `zfs snapshot', and then specify the pool and the snapshot name: root-shell> zfs snapshot scratchpool@snap1 To get a list of snapshots already taken: root-shell> zfs list -t snapshot NAME USED AVAIL REFER MOUNTPOINT scratchpool@snap1 0 - 24.5K - scratchpool@snap2 0 - 24.5K - The snapshots themselves are stored within the file system metadata, and the space required to keep them varies as time goes on because of the way the snapshots are created. The initial creation of a snapshot is really quick, because instead of taking an entire copy of the data and metadata required to hold the entire snapshot, ZFS merely records the point in time and metadata of when the snapshot was created. As more changes to the original file system are made, the size of the snapshot increases because more space is required to keep the record of the old blocks. Furthermore, if you create lots of snapshots, say one per day, and then delete the snapshots from earlier in the week, the size of the newer snapshots may also increase, as the changes that make up the newer state have to be included in the more recent snapshots, rather than being spread over the seven snapshots that make up the week. The only issue, from a backup perspective, is that snapshots exist within the confines of the original file system. To get the snapshot out into a format that you can copy to another file system, tape, etc. you use the `zfs send' command to create a stream version of the snapshot. For example, to write out the snapshot to a file: root-shell> zfs send scratchpool@snap1 >/backup/scratchpool-snap1 Or tape: root-shell> zfs send scratchpool@snap1 >/dev/rmt/0 You can also write out the incremental changes between two snapshots using `zfs send': root-shell> zfs send scratchpool@snap1 scratchpool@snap2 >/backup/scratchpool-changes To recover a snapshot, you use `zfs recv' which applies the snapshot information either to a new file system, or to an existing one.  File: manual.info, Node: ha-zfs-config, Next: ha-zfs-mysql, Prev: ha-zfs-replication, Up: ha-zfs-replication 15.5.1 Using ZFS for File System Replication -------------------------------------------- Because `zfs send' and `zfs recv' use streams to exchange data, you can use them to replicate information from one system to another by combining `zfs send', `ssh', and `zfs recv'. For example, if a snapshot of the `scratchpool' file system has been created and this needs to be copied to a new system or file system called `slavepool'. You would use the following command, combining the snapshot of `scratchpool', the transmission to the slave machine (using `ssh'), and the recovery of the snapshot on the slave using `zfs recv': root-shell> zfs send scratchpool@snap1 |ssh mc@slave pfexec zfs recv -F slavepool The first part, `zfs send scratchpool@snap1', streams the snapshot, the second, `ssh mc@slave', and the third, `pfexec zfs recv -F slavepool', receives the streamed snapshot data and writes it to slavepool. In this instance, I've specified the `-F' option which forces the snapshot data to be applied, and is therefore destructive. This is fine, as I'm creating the first version of my replicated file system. On the slave machine, the replicated file system contains the exact same content: root-shell> ls -al /slavepool/ total 23 drwxr-xr-x 6 root root 7 Nov 8 09:13 ./ drwxr-xr-x 29 root root 34 Nov 9 07:06 ../ drwxr-xr-x 31 root bin 50 Jul 21 07:32 DTT/ drwxr-xr-x 4 root bin 5 Jul 21 07:32 SUNWmlib/ drwxr-xr-x 14 root sys 16 Nov 5 09:56 SUNWspro/ drwxrwxrwx 19 1000 1000 40 Nov 6 19:16 emacs-22.1/ Once a snapshot has been created, to synchronize the file system again, you need to create a new snapshot, and then use the incremental snapshot feature of `zfs send' to send the changes between the two snapshots to the slave machine again: root-shell> zfs send -i scratchpool@snapshot1 scratchpool@snapshot2 |ssh mc@192.168.0.93 pfexec zfs recv slavepool Without further modification, this operation fails, because the file system on the slave machine can currently be modified, and you can't apply the incremental changes to a destination file system that has changed. It is the metadata that has changed. The metadata about the file system, like the last time it was accessed - in this case, it is our `ls' that caused the problem. To prevent changes on the slave file system, you must set the file system on the slave to be read-only: root-shell> zfs set readonly=on slavepool Setting `readonly' means that you cannot change the file system on the slave by normal means, including the file system metadata. Operations that would normally update metadata (like our `ls') silently perform their function without attempting to update the file system state. In essence, the slave file system is nothing but a static copy of the original file system. However, even when configured to to be read-only, a file system can have snapshots applied to it. Now the file system is read only, re-run the initial copy: root-shell> zfs send scratchpool@snap1 |ssh mc@slave pfexec zfs recv -F slavepool Now you can make changes to the original file system and replicate them to the slave.  File: manual.info, Node: ha-zfs-mysql, Next: ha-zfs-mysql-recovery, Prev: ha-zfs-config, Up: ha-zfs-replication 15.5.2 Configuring MySQL for ZFS Replication -------------------------------------------- Configuring MySQL on the source file system is a case of creating the data on the file system that you intend to replicate. The configuration file in the example below has been updated to use `/scratchpool/mysql-data' as the data directory, and now you can initialize the tables: root-shell> mysql_install_db --defaults-file=/etc/mysql/5.0/my.cnf --user=mysql To synchronize the initial information, perform a new snapshot and then send an incremental snapshot to the slave using `zfs send': root-shell> zfs snapshot scratchpool@snap2 root-shell> zfs send -i scratchpool@snap1 scratchpool@snap2|ssh mc@192.168.0.93 pfexec zfs recv slavepool Doublecheck that the slave has the data by looking at the MySQL data directory on the `slavepool': root-shell> ls -al /slavepool/mysql-data/ Now you can start up MySQL, create some data, and then replicate the changes using `zfs send'/` zfs recv' to the slave to synchronize the changes. The rate at which you perform the synchronization depends on your application and environment. The limitation is the speed required to perform the snapshot and then to send the changes over the network. To automate the process, create a script that performs the snapshot, send, and receive operation, and then use `cron' to synchronize the changes at set times or intervals. For automated operations, see Tim Foster's zfs replication tool (http://blogs.sun.com/timf/entry/zfs_automatic_snapshots_now_with).  File: manual.info, Node: ha-zfs-mysql-recovery, Prev: ha-zfs-mysql, Up: ha-zfs-replication 15.5.3 Handling MySQL Recovery with ZFS --------------------------------------- When using ZFS replication to provide a constant copy of your data, ensure that you can recover your tables, either manually or automatically, in the event of a failure of the original system. In the event of a failure, follow this sequence: 1. Stop the script on the master, if it is still up and running. 2. Set the slave file system to be read/write: root-shell> zfs set readonly=off slavepool 3. Start up *Note `mysqld': mysqld. on the slave. If you are using `InnoDB', `Falcon' or `Maria' you get auto-recovery, if it is needed, to make sure the table data is correct, as shown here when I started up from our mid-INSERT snapshot: InnoDB: The log sequence number in ibdata files does not match InnoDB: the log sequence number in the ib_logfiles! 081109 15:59:59 InnoDB: Database was not shut down normally! InnoDB: Starting crash recovery. InnoDB: Reading tablespace information from the .ibd files... InnoDB: Restoring possible half-written data pages from the doublewrite InnoDB: buffer... 081109 16:00:03 InnoDB: Started; log sequence number 0 1142807951 081109 16:00:03 [Note] /slavepool/mysql-5.0.67-solaris10-i386/bin/mysqld: ready for connections. Version: '5.0.67' socket: '/tmp/mysql.sock' port: 3306 MySQL Community Server (GPL) On MyISAM, or other tables, you might need to run `REPAIR TABLE', and you might even have lost some information. Use a recovery-capable storage engine and a regular synchronization schedule to reduce the risk for significant data loss.  File: manual.info, Node: ha-memcached, Next: mysql-proxy, Prev: ha-zfs-replication, Up: ha-overview 15.6 Using MySQL with `memcached' ================================= * Menu: * ha-memcached-install:: Installing `memcached' * ha-memcached-using:: Using `memcached' * ha-memcached-interfaces:: `memcached' Interfaces * ha-memcached-stats:: Getting `memcached' Statistics * ha-memcached-faq:: `memcached' FAQ The largest problem with scalability within a typical environment is the speed with which you can access information. For frequently accessed information, using MySQL can be slow because each access of information requires execution of the SQL query and recovery of the information from the database. This also means that queries on tables that are locked or blocking may delay your query and reduce the speed of recovery of information. `memcached' is a simple, yet highly scalable key-based cache that stores data and objects wherever dedicated or spare RAM is available for very quick access by applications. To use, you run `memcached' on one or more hosts and then use the shared cache to store objects. Because each host's RAM is storing information, the access speed is much faster than loading the information from disk. This can provide a significant performance boost in retrieving data versus loading the data natively from a database. Also, because the cache is just a repository for information, you can use the cache to store any data, including complex structures that would normally require a significant amount of effort to create, but in a ready-to-use format, helping to reduce the load on your MySQL servers. The typical usage environment is to modify your application so that information is read from the cache provided by `memcached'. If the information isn't in `memcached', then the data is loaded from the MySQL database and written into the cache so that future requests for the same object benefit from the cached data. For a typical deployment layout, see *Note ha-memcached-fig-overview::. FIGURE GOES HERE: `memcached' Architecture Overview In the example structure, any of the clients can contact one of the `memcached' servers to request a given key. Each client is configured to talk to all of the servers shown in the illustration. Within the client, when the request is made to store the information, the key used to reference the data is hashed and this hash is then used to select one of the `memcached' servers. The selection of the `memcached' server takes place on the client before the server is contacted, keeping the process lightweight. The same algorithm is used again when a client requests the same key. The same key generates the same hash, and the same `memcached' server is selected as the source for the data. Using this method, the cached data is spread among all of the `memcached' servers, and the cached information is accessible from any client. The result is a distributed, memory-based, cache that can return information, particularly complex data and structures, much faster than natively reading the information from the database. The data held within a `memcached' server is never stored on disk (only in RAM, which means there is no persistence of data), and the RAM cache is always populated from the backing store (a MySQL database). If a `memcached' server fails, the data can always be recovered from the MySQL database, albeit at a slower speed than loading the information from the cache. In April 2011, MySQL announced the preview of a new memcached interface for the InnoDB and MySQL Cluster storage engines. Using the memcached API, web services can directly access the InnoDB and MySQL Cluster storage engines without transformations to SQL, ensuring low latency and high throughput for read/write queries. Operations such as SQL parsing are eliminated and more of the server's hardware resources (CPU, memory and I/O) are dedicated to servicing the query within the storage engine itself. These are targeted to be incorporated into future MySQL 5.6 Milestone and MySQL Cluster Development Releases. You can learn more about these interfaces from this Dev Zone article: `http://dev.mysql.com/tech-resources/articles/nosql-to-mysql-with-memcached.html'.  File: manual.info, Node: ha-memcached-install, Next: ha-memcached-using, Prev: ha-memcached, Up: ha-memcached 15.6.1 Installing `memcached' ----------------------------- You can build and install `memcached' from the source code directly, or you can use an existing operating system package or installation. *Installing `memcached' from a Binary Distribution* To install `memcached' on a Red Hat, or Fedora host, use `yum': root-shell> yum install memcached *Note*: On CentOS, you may be able to obtain a suitable RPM from another source, or use the source tarball. To install `memcached' on a Debian or Ubuntu host, use `apt-get': root-shell> apt-get install memcached To install `memcached' on a Gentoo host, use `emerge': root-shell> emerge install memcached *Building `memcached' from Source* On other Unix-based platforms, including Solaris, AIX, HP-UX and Mac OS X, and Linux distributions not mentioned already, you must install from source. For Linux, make sure you have a 2.6-based kernel, which includes the improved `epoll' interface. For all platforms, ensure that you have `libevent' 1.1 or higher installed. You can obtain `libevent' from `libevent' web page (http://www.monkey.org/~provos/libevent/). You can obtain the source for `memcached' from `memcached' Web site (http://www.danga.com/memcached). To build `memcached', follow these steps: 1. Extract the `memcached' source package: shell> gunzip -c memcached-1.2.5.tar.gz | tar xf - 2. Change to the `memcached-1.2.5 directory:' shell> cd memcached-1.2.5 3. Run `configure' shell> ./configure Some additional options you may want to specify to `configure': * `--prefix' If you want to specify a different installation directory, use the `--prefix' option: shell> ./configure --prefix=/opt The default is to use the `/usr/local' directory. * `--with-libevent' If you have installed `libevent' and `configure' cannot find the library, use the `--with-libevent' option to specify the location of the installed library. * `--enable-64bit' To build a 64-bit version of `memcached' (which enables you to use a single instance with a large RAM allocation), use `--enable-64bit'. * `--enable-threads' To enable multi-threading support in `memcached', which improves the response times on servers with a heavy load, use `--enable-threads'. You must have support for the POSIX threads within your operating system to enable thread support. For more information on the threading support, see *Note ha-memcached-using-threads::. * `--enable-dtrace' `memcached' includes a range of DTrace threads that can be used to monitor and benchmark a `memcached' instance. For more information, see *Note ha-memcached-using-dtrace::. 4. Run `make' to build `memcached': shell> make 5. Run `make install' to install `memcached': shell> make install  File: manual.info, Node: ha-memcached-using, Next: ha-memcached-interfaces, Prev: ha-memcached-install, Up: ha-memcached 15.6.2 Using `memcached' ------------------------ * Menu: * ha-memcached-using-deployment:: `memcached' Deployment * ha-memcached-using-namespaces:: Using namespaces * ha-memcached-using-expiry:: Data Expiry * ha-memcached-using-hashtypes:: `memcached' Hashing/Distribution Types * ha-memcached-using-dtrace:: Using `memcached' and DTrace * ha-memcached-using-memory:: Memory allocation within `memcached' * ha-memcached-using-threads:: `memcached' thread Support * ha-memcached-using-logs:: `memcached' Logs To start using `memcached', you must start the `memcached' service on one or more servers. Running `memcached' sets up the server, allocates the memory and starts listening for connections from clients. *Note*: You do not need to be privileged user (`root') to run `memcached' unless you want to listen on one of the privileged TCP/IP ports (below 1024). You must, however, use a user that has not had their memory limits restricted using `setrlimit' or similar. To start the server, run `memcached' as a nonprivileged (that is, non-`root') user: shell> memcached By default, `memcached' uses the following settings: * Memory allocation of 64MB * Listens for connections on all network interfaces, using port 11211 * Supports a maximum of 1024 simultaneous connections Typically, you would specify the full combination of options that you want when starting `memcached', and normally provide a startup script to handle the initialization of `memcached'. For example, the following line starts `memcached' with a maximum of 1024MB RAM for the cache, listening on port 11211 on the IP address 192.168.0.110, running has a background daemon: shell> memcached -d -m 1024 -p 11211 -l 192.168.0.110 To ensure that `memcached' is started up on boot, check the init script and configuration parameters. `memcached' supports the following options: * `-u user' If you start `memcached' as `root', use the `-u' option to specify the user for executing `memcached': shell> memcached -u memcache * `-m memory' Set the amount of memory allocated to `memcached' for object storage. Default is 64MB. To increase the amount of memory allocated for the cache, use the `-m' option to specify the amount of RAM to be allocated (in megabytes). The more RAM you allocate, the more data you can store and therefore the more effective your cache is. *Warning*: Do not specify a memory allocation larger than your available RAM. If you specify too large a value, then some RAM allocated for `memcached' uses swap space, and not physical RAM. This may lead to delays when storing and retrieving values, because data is swapped to disk, instead of storing the data directly in RAM. You can use the output of the `vmstat' command to get the free memory, as shown in `free' column: shell> vmstat kthr memory page disk faults cpu r b w swap free re mf pi po fr de sr s1 s2 -- -- in sy cs us sy id 0 0 0 5170504 3450392 2 7 2 0 0 0 4 0 0 0 0 296 54 199 0 0 100 For example, to allocate 3GB of RAM: shell> memcached -m 3072 On 32-bit x86 systems where you are using PAE to access memory above the 4GB limit, you cannot allocate RAM beyond the maximum process size. You can get around this by running multiple instances of `memcached', each listening on a different port: shell> memcached -m 1024 -p11211 shell> memcached -m 1024 -p11212 shell> memcached -m 1024 -p11213 *Note*: On all systems, particularly 32-bit, ensure that you leave enough room for both `memcached' application in addition to the memory setting. For example, if you have a dedicated `memcached' host with 4GB of RAM, do not set the memory size above 3500MB. Failure to do this may cause either a crash or severe performance issues. * `-l interface' Specify a network interface/address to listen for connections. The default is to listen on all available address (`INADDR_ANY'). shell> memcached -l 192.168.0.110 Support for IPv6 address support was added in `memcached' 1.2.5. * `-p port' Specify the TCP port to use for connections. Default is 18080. shell> memcached -p 18080 * `-U port' Specify the UDP port to use for connections. Default is 11211, 0 switches UDP off. shell> memcached -U 18080 * `-s socket' Specify a Unix socket to listen on. If you are running `memcached' on the same server as the clients, you can disable the network interface and use a local UNIX socket using the `-s' option: shell> memcached -s /tmp/memcached Using a UNIX socket automatically disables network support, and saves network ports (allowing more ports to be used by your web server or other process). * `-a mask' Specify the access mask to be used for the Unix socket, in octal. Default is 0700. * `-c connections' Specify the maximum number of simultaneous connections to the `memcached' service. The default is 1024. shell> memcached -c 2048 Use this option, either to reduce the number of connections (to prevent overloading `memcached' service) or to increase the number to make more effective use of the server running `memcached' server. * `-t threads' Specify the number of threads to use when processing incoming requests. By default, `memcached' is configured to use 4 concurrent threads. The threading improves the performance of storing and retrieving data in the cache, using a locking system to prevent different threads overwriting or updating the same values. You may want to increase or decrease the number of threads, use the `-t' option: shell> memcached -t 8 * `-d' Run `memcached' as a daemon (background) process: shell> memcached -d * `-r' Maximize the size of the core file limit. In the event of a failure, this attempts to dump the entire memory space to disk as a core file, up to any limits imposed by `setrlimit'. * `-M' Return an error to the client when the memory has been exhausted. This replaces the normal behavior of removing older items from the cache to make way for new items. * `-k' Lock down all paged memory. This reserves the memory before use, instead of allocating new slabs of memory as new items are stored in the cache. *Note*: There is a user-level limit on how much memory you can lock. Trying to allocate more than the available memory fails. You can set the limit for the user you started the daemon with (not for the `-u user' user) within the shell by using `ulimit -S -l NUM_KB' * `-v' Verbose mode. Prints errors and warnings while executing the main event loop. * `-vv' Very verbose mode. In addition to information printed by `-v', also prints each client command and the response. * `-vvv' Extremely verbose mode. In addition to information printed by `-vv', also show the internal state transitions. * `-h' Print the help message and exit. * `-i' Print the `memcached' and `libevent' license. * `-I mem' Specify the maximum size permitted for storing an object within the `memcached' instance. The size supports a unit postfix (`k' for kilobytes, `m' for megabytes). For example, to increase the maximum supported object size to 32MB: shell> memcached -I 32m The maximum object size you can specify is 128MB, the default remains at 1MB. This option was added in 1.4.2. * `-b' Set the backlog queue limit. The backlog queue configures how many network connections can be waiting to be processed by `memcached'. Increasing this limit may reduce errors received by the client that it is not able to connect to the `memcached' instance, but does not improve the performance of the server. The default is 1024. * `-P pidfile' Save the process ID of the `memcached' instance into `file'. * `-f' Set the chunk size growth factor. When allocating new memory chunks, the allocated size of new chunks is determined by multiplying the default slab size by this factor. To see the effects of this option without extensive testing, use the `-vv' command-line option to show the calculated slab sizes. For more information, see *Note ha-memcached-using-logs::. * `-n bytes' The minimum space allocated for the key+value+flags information. The default is 48 bytes. * `-L' On systems that support large memory pages, enables large memory page use. Using large memory pages enables `memcached' to allocate the item cache in one large chunk, which can improve the performance by reducing the number misses when accessing memory. * `-C' Disable the use of compare and swap (CAS) operations. This option was added in `memcached' 1.3.x. * `-D char' Set the default character to be used as a delimiter between the key prefixes and IDs. This is used for the per-prefix statistics reporting (see *Note ha-memcached-stats::). The default is the colon (`:'). If this option is used, statistics collection is turned on automatically. If not used, you can enable stats collection by sending the `stats detail on' command to the server. This option was added in `memcached' 1.3.x. * `-R num' Sets the maximum number of requests per event process. The default is 20. * `-B protocol' Set the binding protocol, that is, the default `memcached' protocol support for client connections. Options are `ascii', `binary' or `auto'. Automatic (`auto') is the default. This option was added in `memcached' 1.4.0.  File: manual.info, Node: ha-memcached-using-deployment, Next: ha-memcached-using-namespaces, Prev: ha-memcached-using, Up: ha-memcached-using 15.6.2.1 `memcached' Deployment ............................... When using `memcached' you can use a number of different potential deployment strategies and topologies. The exact strategy to use depends on your application and environment. When developing a system for deploying `memcached' within your system, keep in mind the following points: * `memcached' is only a caching mechanism. It shouldn't be used to store information that you cannot otherwise afford to lose and then load from a different location. * There is no security built into the `memcached' protocol. At a minimum, make sure that the servers running `memcached' are only accessible from inside your network, and that the network ports being used are blocked (using a firewall or similar). If the information on the `memcached' servers that is being stored is any sensitive, then encrypt the information before storing it in `memcached'. * `memcached' does not provide any sort of failover. Because there is no communication between different `memcached' instances. If an instance fails, your application must capable of removing it from the list, reloading the data and then writing data to another `memcached' instance. * Latency between the clients and the `memcached' can be a problem if you are using different physical machines for these tasks. If you find that the latency is a problem, move the `memcached' instances to be on the clients. * Key length is determined by the `memcached' server. The default maximum key size is 250 bytes. * Using a single `memcached' instance, especially for multiple clients, is generally a bad idea as it introduces a single point of failure. Instead provide at least two `memcached' instances so that a failure can be handled appropriately. If possible, you should create as many `memcached' nodes as possible. When adding and removing `memcached' instances from a pool, the hashing and distribution of key/value pairs may be affected. For information on how to avoid problems, see *Note ha-memcached-using-hashtypes::.  File: manual.info, Node: ha-memcached-using-namespaces, Next: ha-memcached-using-expiry, Prev: ha-memcached-using-deployment, Up: ha-memcached-using 15.6.2.2 Using namespaces ......................... The `memcached' cache is a very simple massive key/value storage system, and as such there is no way of compartmentalizing data automatically into different sections. For example, if you are storing information by the unique ID returned from a MySQL database, then storing the data from two different tables could run into issues because the same ID might be valid in both tables. Some interfaces provide an automated mechanism for creating _namespaces_ when storing information into the cache. In practice, these namespaces are merely a prefix before a given ID that is applied every time a value is stored or retrieve from the cache. You can implement the same basic principle by using keys that describe the object and the unique identifier within the key that you supply when the object is stored. For example, when storing user data, prefix the ID of the user with `user:' or `user-'. *Note*: Using namespaces or prefixes only controls the keys stored/retrieved. There is no security within `memcached', and therefore no way to enforce that a particular client only accesses keys with a particular namespace. Namespaces are only useful as a method of identifying data and preventing corruption of key/value pairs.  File: manual.info, Node: ha-memcached-using-expiry, Next: ha-memcached-using-hashtypes, Prev: ha-memcached-using-namespaces, Up: ha-memcached-using 15.6.2.3 Data Expiry .................... There are two types of data expiry within a `memcached' instance. The first type is applied at the point when you store a new key/value pair into the `memcached' instance. If there is not enough space within a suitable slab to store the value, then an existing least recently used (LRU) object is removed (evicted) from the cache to make room for the new item. The LRU algorithm ensures that the object that is removed is one that is either no longer in active use or that was used so long ago that its data is potentially out of date or of little value. However, in a system where the memory allocated to `memcached' is smaller than the number of regularly used objects required in the cache, a lot of expired items could be removed from the cache even though they are in active use. You use the statistics mechanism to get a better idea of the level of evictions (expired objects). For more information, see *Note ha-memcached-stats::. You can change this eviction behavior by setting the `-M' command-line option when starting `memcached'. This option forces an error to be returned when the memory has been exhausted, instead of automatically evicting older data. The second type of expiry system is an explicit mechanism that you can set when a key/value pair is inserted into the cache, or when deleting an item from the cache. Using an expiration time can be a useful way of ensuring that the data in the cache is up to date and in line with your application needs and requirements. A typical scenario for explicitly setting the expiry time might include caching session data for a user when accessing a Web site. `memcached' uses a lazy expiry mechanism where the explicit expiry time that has been set is compared with the current time when the object is requested. Only objects that have not expired are returned. You can also set the expiry time when explicitly deleting an object from the cache. In this case, the expiry time is really a timeout and indicates the period when any attempts to set the value for a given key are rejected.  File: manual.info, Node: ha-memcached-using-hashtypes, Next: ha-memcached-using-dtrace, Prev: ha-memcached-using-expiry, Up: ha-memcached-using 15.6.2.4 `memcached' Hashing/Distribution Types ............................................... The `memcached' client interface supports a number of different distribution algorithms that are used in multi-server configurations to determine which host should be used when setting or getting data from a given `memcached' instance. When you get or set a value, a hash is constructed from the supplied key and then used to select a host from the list of configured servers. Because the hashing mechanism uses the supplied key as the basis for the hash, the same server is selected during both set and get operations. You can think of this process as follows. Given an array of servers (a, b, and c), the client uses a hashing algorithm that returns an integer based on the key being stored or retrieved. The resulting value is then used to select a server from the list of servers configured in the client. Most standard client hashing within `memcache' clients uses a simple modulus calculation on the value against the number of configured `memcached' servers. You can summarize the process in pseudocode as: @memcservers = ['a.memc','b.memc','c.memc']; $value = hash($key); $chosen = $value % length(@memcservers); Replacing the above with values: @memcservers = ['a.memc','b.memc','c.memc']; $value = hash('myid'); $chosen = 7009 % 3; In the above example, the client hashing algorithm chooses the server at index 1 (`7009 % 3 = 1'), and store or retrieve the key and value with that server. *Note*: This selection and hashing process is handled automatically by the `memcached' client you are using; you need only provide the list of `memcached' servers that you want to use. You can see a graphical representation of this below in *Note ha-memcached-using-hashtypes-fig-selection::. FIGURE GOES HERE: `memcached' Hash Selection The same hashing and selection process takes place during any operation on the specified key within the `memcached' client. Using this method provides a number of advantages: * The hashing and selection of the server to contact is handled entirely within the client. This eliminates the need to perform network communication to determine the right machine to contact. * Because the determination of the `memcached' server occurs entirely within the client, the server can be selected automatically regardless of the operation being executed (set, get, increment, etc.). * Because the determination is handled within the client, the hashing algorithm returns the same value for a given key; values are not affected or reset by differences in the server environment. * Selection is very fast. The hashing algorithm on the key value is quick and the resulting selection of the server is from a simple array of available machines. * Using client-side hashing simplifies the distribution of data over each `memcached' server. Natural distribution of the values returned by the hashing algorithm means that keys are automatically spread over the available servers. Providing that the list of servers configured within the client remains the same, the same stored key returns the same value, and therefore selects the same server. However, if you do not use the same hashing mechanism then the same data may be recorded on different servers by different interfaces, both wasting space on your `memcached' and leading to potential differences in the information. *Note*: One way to use a multi-interface compatible hashing mechanism is to use the `libmemcached' library and the associated interfaces. Because the interfaces for the different languages (including C, Ruby, Perl and Python) use the same client library interface, they always generate the same hash code from the ID. The problem with client-side selection of the server is that the list of the servers (including their sequential order) _must_ remain consistent on each client using the `memcached' servers, and the servers must be available. If you try to perform an operation on a key when: * A new `memcached' instance has been added to the list of available instances * A `memcached' instance has been removed from the list of available instances * The order of the `memcached' instances has changed When the hashing algorithm is used on the given key, but with a different list of servers, the hash calculation may choose a different server from the list. If a new `memcached' instance is added into the list of servers, as `new.memc' is in the example below, then a GET operation using the same key, `myid', can result in a cache-miss. This is because the same value is computed from the key, which selects the same index from the array of servers, but index 2 now points to the new server, not the server `c.memc' where the data was originally stored. This would result in a cache miss, even though the key exists within the cache on another `memcached' instance. FIGURE GOES HERE: `memcached' Hash Selection with New `memcached' instance This means that servers `c.memc' and `new.memc ' both contain the information for key `myid', but the information stored against the key in eachs server may be different in each instance. A more significant problem is a much higher number of cache-misses when retrieving data, as the addition of a new server changes the distribution of keys, and this in turn requires rebuilding the cached data on the `memcached' instances, causing an increase in database reads. The same effect can occur if you actively manage the list of servers configured in your clients, adding and removing the configured `memcached' instances as each instance is identified as being available. For example, removing a `memcached' instance when the client notices that the instance can no longer be contacted can cause the server selection to fail as described here. To prevent this causing significant problems and invalidating your cache, you can select the hashing algorithm used to select the server. There are two common types of hashing algorithm, _consistent_ and _modula_. With _consistent_ hashing algorithms, the same key when applied to a list of servers always uses the same server to store or retrieve the keys, even if the list of configured servers changes. This means that you can add and remove servers from the configure list and always use the same server for a given key. There are two types of consistent hashing algorithms available, Ketama and Wheel. Both types are supported by `libmemcached', and implementations are available for PHP and Java. Any consistent hashing algorithm has some limitations. When you add servers to an existing list of configured servers, keys are distributed to the new servers as part of the normal distribution. When you remove servers from the list, the keys are re-allocated to another server within the list, meaning that the cache needs to be re-populated with the information. Also, a consistent hashing algorithm does not resolve the issue where you want consistent selection of a server across multiple clients, but where each client contains a different list of servers. The consistency is enforced only within a single client. With a _modula_ hashing algorithm, the client selects a server by first computing the hash and then choosing a server from the list of configured servers. As the list of servers changes, so the server selected when using a modula hashing algorithm also changes. The result is the behavior described above; changes to the list of servers mean that different servers are selected when retrieving data, leading to cache misses and increase in database load as the cache is re-seeded with information. If you use only a single `memcached' instance for each client, or your list of `memcached' servers configured for a client never changes, then the selection of a hashing algorithm is irrelevant, as it has no noticeable effect. If you change your servers regularly, or you use a common set of servers that are shared among a large number of clients, then using a consistent hashing algorithm should help to ensure that your cache data is not duplicated and the data is evenly distributed.  File: manual.info, Node: ha-memcached-using-dtrace, Next: ha-memcached-using-memory, Prev: ha-memcached-using-hashtypes, Up: ha-memcached-using 15.6.2.5 Using `memcached' and DTrace ..................................... `memcached' includes a number of different DTrace probes that can be used to monitor the operation of the server. The probes included can monitor individual connections, slab allocations, and modifications to the hash table when a key/value pair is added, updated, or removed. For more information on DTrace and writing DTrace scripts, read the DTrace User Guide (http://docs.sun.com/app/docs/doc/819-5488?l=en). Support for DTrace probes was added to `memcached' 1.2.6 includes a number of DTrace probes that can be used to help monitor your application. DTrace is supported on Solaris 10, OpenSolaris, Mac OS X 10.5 and FreeBSD. To enable the DTrace probes in `memcached', build from source and use the `--enable-dtrace' option. For more information, see *Note ha-memcached-install::. The probes supported by `memcached' are: * `conn-allocate(connid)' Fired when a connection object is allocated from the connection pool. * `connid': The connection ID * `conn-release(connid)' Fired when a connection object is released back to the connection pool. Arguments: * `connid': The connection ID * `conn-create(ptr)' Fired when a new connection object is being created (that is, there are no free connection objects in the connection pool). Arguments: * `ptr': A pointer to the connection object * `conn-destroy(ptr)' Fired when a connection object is being destroyed. Arguments: * `ptr': A pointer to the connection object * `conn-dispatch(connid, threadid)' Fired when a connection is dispatched from the main or connection-management thread to a worker thread. Arguments: * `connid': The connection ID * `threadid': The thread ID * `slabs-allocate(size, slabclass, slabsize, ptr)' Allocate memory from the slab allocator Arguments: * `size': The requested size * `slabclass': The allocation is fulfilled in this class * `slabsize': The size of each item in this class * `ptr': A pointer to allocated memory * `slabs-allocate-failed(size, slabclass)' Failed to allocate memory (out of memory) Arguments: * `size': The requested size * `slabclass': The class that failed to fulfill the request * `slabs-slabclass-allocate(slabclass)' Fired when a slab class needs more space Arguments: * `slabclass': The class that needs more memory * `slabs-slabclass-allocate-failed(slabclass)' Failed to allocate memory (out of memory) Arguments: * `slabclass': The class that failed to grab more memory * `slabs-free(size, slabclass, ptr)' Release memory Arguments: * `size': The size of the memory * `slabclass': The class the memory belongs to * `ptr': A pointer to the memory to release * `assoc-find(key, depth)' Fired when the when we have searched the hash table for a named key. These two elements provide an insight in how well the hash function operates. Traversals are a sign of a less optimal function, wasting cpu capacity. Arguments: * `key': The key searched for * `depth': The depth in the list of hash table * `assoc-insert(key, nokeys)' Fired when a new item has been inserted. Arguments: * `key': The key just inserted * `nokeys': The total number of keys currently being stored, including the key for which insert was called. * `assoc-delete(key, nokeys)' Fired when a new item has been removed. Arguments: * `key': The key just deleted * `nokeys': The total number of keys currently being stored, excluding the key for which delete was called. * `item-link(key, size)' Fired when an item is being linked in the cache Arguments: * `key': The items key * `size': The size of the data * `item-unlink(key, size)' Fired when an item is being deleted Arguments: * `key': The items key * `size': The size of the data * `item-remove(key, size)' Fired when the refcount for an item is reduced Arguments: * `key': The items key * `size': The size of the data * `item-update(key, size)' Fired when the "last referenced" time is updated Arguments: * `key': The items key * `size': The size of the data * `item-replace(oldkey, oldsize, newkey, newsize)' Fired when an item is being replaced with another item Arguments: * `oldkey': The key of the item to replace * `oldsize': The size of the old item * `newkey': The key of the new item * `newsize': The size of the new item * `process-command-start(connid, request, size)' Fired when the processing of a command starts Arguments: * `connid': The connection ID * `request': The incoming request * `size': The size of the request * `process-command-end(connid, response, size)' Fired when the processing of a command is done Arguments: * `connid': The connection ID * `response': The response to send back to the client * `size': The size of the response * `command-get(connid, key, size)' Fired for a get-command Arguments: * `connid': The connection ID * `key': The requested key * `size': The size of the key's data (or -1 if not found) * `command-gets(connid, key, size, casid)' Fired for a gets command Arguments: * `connid': The connection ID * `key': The requested key * `size': The size of the key's data (or -1 if not found) * `casid': The casid for the item * `command-add(connid, key, size)' Fired for a add-command Arguments: * `connid': The connection ID * `key': The requested key * `size': The new size of the key's data (or -1 if not found) * `command-set(connid, key, size)' Fired for a set-command Arguments: * `connid': The connection ID * `key': The requested key * `size': The new size of the key's data (or -1 if not found) * `command-replace(connid, key, size)' Fired for a replace-command Arguments: * `connid': The connection ID * `key': The requested key * `size': The new size of the key's data (or -1 if not found) * `command-prepend(connid, key, size)' Fired for a prepend-command Arguments: * `connid': The connection ID * `key': The requested key * `size': The new size of the key's data (or -1 if not found) * `command-append(connid, key, size)' Fired for a append-command Arguments: * `connid': The connection ID * `key': The requested key * `size': The new size of the key's data (or -1 if not found) * `command-cas(connid, key, size, casid)' Fired for a cas-command Arguments: * `connid': The connection ID * `key': The requested key * `size': The size of the key's data (or -1 if not found) * `casid': The cas ID requested * `command-incr(connid, key, val)' Fired for incr command Arguments: * `connid': The connection ID * `key': The requested key * `val': The new value * `command-decr(connid, key, val)' Fired for decr command Arguments: * `connid': The connection ID * `key': The requested key * `val': The new value * `command-delete(connid, key, exptime)' Fired for a delete command Arguments: * `connid': The connection ID * `key': The requested key * `exptime': The expiry time  File: manual.info, Node: ha-memcached-using-memory, Next: ha-memcached-using-threads, Prev: ha-memcached-using-dtrace, Up: ha-memcached-using 15.6.2.6 Memory allocation within `memcached' ............................................. When you first start `memcached', the memory that you have configured is not automatically allocated. Instead, `memcached' only starts allocating and reserving physical memory once you start saving information into the cache. When you start to store data into the cache, `memcached' does not allocate the memory for the data on an item by item basis. Instead, a slab allocation is used to optimize memory usage and prevent memory fragmentation when information expires from the cache. With slab allocation, memory is reserved in blocks of 1MB. The slab is divided up into a number of blocks of equal size. When you try to store a value into the cache, `memcached' checks the size of the value that you are adding to the cache and determines which slab contains the right size allocation for the item. If a slab with the item size already exists, the item is written to the block within the slab. If the new item is bigger than the size of any existing blocks, then a new slab is created, divided up into blocks of a suitable size. If an existing slab with the right block size already exists, but there are no free blocks, a new slab is created. If you update an existing item with data that is larger than the existing block allocation for that key, then the key is re-allocated into a suitable slab. For example, the default size for the smallest block is 88 bytes (40 bytes of value, and the default 48 bytes for the key and flag data). If the size of the first item you store into the cache is less than 40 bytes, then a slab with a block size of 88 bytes is created and the value stored. If the size of the data that you want to store is larger than this value, then the block size is increased by the chunk size factor until a block size large enough to hold the value is determined. The block size is always a function of the scale factor, rounded up to a block size which is exactly divisible into the chunk size. For a sample of the structure, see *Note ha-memcached-fig-slabs::. FIGURE GOES HERE: Memory Allocation in `memcached' The result is that you have multiple pages allocated within the range of memory allocated to `memcached'. Each page is 1MB in size (by default), and is split into a different number of chunks, according to the chunk size required to store the key/value pairs. Each instance has multiple pages allocated, and a page is always created when a new item needs to be created requiring a chunk of a particular size. A slab may consist of multiple pages, and each page within a slab contains an equal number of chunks. The chunk size of a new slab is determined by the base chunk size combined with the chunk size growth factor. For example, if the initial chunks are 104 bytes in size, and the default chunk size growth factor is used (1.25), then the next chunk size allocated would be the best power of 2 fit for 104*1.25, or 136 bytes. Allocating the pages in this way ensures that memory does not get fragmented. However, depending on the distribution of the objects that you want to store, it may lead to an inefficient distribution of the slabs and chunks if you have significantly different sized items. For example, having a relatively small number of items within each chunk size may waste a lot of memory with just few chunks in each allocated page. You can tune the growth factor to reduce this effect by using the `-f' command line option, which adapts the growth factor applied to make more effective use of the chunks and slabs allocated. For information on how to determine the current slab allocation statistics, see *Note ha-memcached-stats-slabs::. If your operating system supports it, you can also start `memcached' with the `-L' command line option. This option preallocates all the memory during startup using large memory pages. This can improve performance by reducing the number of misses in the CPU memory cache.  File: manual.info, Node: ha-memcached-using-threads, Next: ha-memcached-using-logs, Prev: ha-memcached-using-memory, Up: ha-memcached-using 15.6.2.7 `memcached' thread Support ................................... If you enable the thread implementation within when building `memcached' from source, then `memcached' uses multiple threads in addition to the `libevent' system to handle requests. When enabled, the threading implementation operates as follows: * Threading is handled by wrapping functions within the code to provide basic protection from updating the same global structures at the same time. * Each thread uses its own instance of the `libevent' to help improve performance. * TCP/IP connections are handled with a single thread listening on the TCP/IP socket. Each connection is then distribution to one of the active threads on a simple round-robin basis. Each connection then operates solely within this thread while the connection remains open. * For UDP connections, all the threads listen to a single UDP socket for incoming requests. Threads that are not currently dealing with another request ignore the incoming packet. One of the remaining, nonbusy, threads reads the request and sends the response. This implementation can lead to increased CPU load as threads wake from sleep to potentially process the request. Using threads can increase the performance on servers that have multiple CPU cores available, as the requests to update the hash table can be spread between the individual threads. However, because of the locking mechanism employed you may want to experiment with different thread values to achieve the best performance based on the number and type of requests within your given workload.  File: manual.info, Node: ha-memcached-using-logs, Prev: ha-memcached-using-threads, Up: ha-memcached-using 15.6.2.8 `memcached' Logs ......................... If you enable verbose mode, using the `-v', `-vv', or `-vvv' options, then the information output by `memcached' includes details of the operations being performed. Without the verbose options, `memcached' normally produces no output during normal operating. * *Output when using `-v'* The lowest verbosity level shows you: * Errors and warnings * Transient errors * Protocol and socket errors, including exhausting available connections * Each registered client connection, including the socket descriptor number and the protocol used. For example: 32: Client using the ascii protocol 33: Client using the ascii protocol Note that the socket descriptor is only valid while the client remains connected. Non-persitant connections may not be effectively represented. Examples of the error messages output at this level include: <%d send buffer was %d, now %d Can't listen for events on fd %d Can't read from libevent pipe Catastrophic: event fd doesn't match conn fd! Couldn't build response Couldn't realloc input buffer Couldn't update event Failed to build UDP headers Failed to read, and not due to blocking Too many open connections Unexpected state %d * *Output when using `-vv'* When using the second level of verbosity, you get more detailed information about protocol operations, keys updated, chunk and network operatings and details. During the initial start-up of `memcached' with this level of verbosity, you are shown the sizes of the individual slab classes, the chunk sizes, and the number of entries per slab. These do not show the allocation of the slabs, just the slabs that would be created when data is added. You are also given information about the listen queues and buffers used to send information. A sample of the output generated for a TCP/IP based system with the default memory and growth factors is given below: shell> memcached -vv slab class 1: chunk size 80 perslab 13107 slab class 2: chunk size 104 perslab 10082 slab class 3: chunk size 136 perslab 7710 slab class 4: chunk size 176 perslab 5957 slab class 5: chunk size 224 perslab 4681 slab class 6: chunk size 280 perslab 3744 slab class 7: chunk size 352 perslab 2978 slab class 8: chunk size 440 perslab 2383 slab class 9: chunk size 552 perslab 1899 slab class 10: chunk size 696 perslab 1506 slab class 11: chunk size 872 perslab 1202 slab class 12: chunk size 1096 perslab 956 slab class 13: chunk size 1376 perslab 762 slab class 14: chunk size 1720 perslab 609 slab class 15: chunk size 2152 perslab 487 slab class 16: chunk size 2696 perslab 388 slab class 17: chunk size 3376 perslab 310 slab class 18: chunk size 4224 perslab 248 slab class 19: chunk size 5280 perslab 198 slab class 20: chunk size 6600 perslab 158 slab class 21: chunk size 8256 perslab 127 slab class 22: chunk size 10320 perslab 101 slab class 23: chunk size 12904 perslab 81 slab class 24: chunk size 16136 perslab 64 slab class 25: chunk size 20176 perslab 51 slab class 26: chunk size 25224 perslab 41 slab class 27: chunk size 31536 perslab 33 slab class 28: chunk size 39424 perslab 26 slab class 29: chunk size 49280 perslab 21 slab class 30: chunk size 61600 perslab 17 slab class 31: chunk size 77000 perslab 13 slab class 32: chunk size 96256 perslab 10 slab class 33: chunk size 120320 perslab 8 slab class 34: chunk size 150400 perslab 6 slab class 35: chunk size 188000 perslab 5 slab class 36: chunk size 235000 perslab 4 slab class 37: chunk size 293752 perslab 3 slab class 38: chunk size 367192 perslab 2 slab class 39: chunk size 458992 perslab 2 <26 server listening (auto-negotiate) <29 server listening (auto-negotiate) <30 send buffer was 57344, now 2097152 <31 send buffer was 57344, now 2097152 <30 server listening (udp) <30 server listening (udp) <31 server listening (udp) <30 server listening (udp) <30 server listening (udp) <31 server listening (udp) <31 server listening (udp) <31 server listening (udp) Using this verbosity level can be a useful way to check the effects of the growth factor used on slabs with different memory allocations, which in turn can be used to better tune the growth factor to suit the data you are storing in the cache. For example, if you set the growth factor to 4 (quadrupling the size of each slab): shell> memcached -f 4 -m 1g -vv slab class 1: chunk size 80 perslab 13107 slab class 2: chunk size 320 perslab 3276 slab class 3: chunk size 1280 perslab 819 slab class 4: chunk size 5120 perslab 204 slab class 5: chunk size 20480 perslab 51 slab class 6: chunk size 81920 perslab 12 slab class 7: chunk size 327680 perslab 3 ... During use of the cache, this verbosity level also prints out detailed information on the storage and recovery of keys and other information. An example of the output during a typical set/get and increment/decrement operation is shown below. 32: Client using the ascii protocol <32 set my_key 0 0 10 >32 STORED <32 set object_key 1 0 36 >32 STORED <32 get my_key >32 sending key my_key >32 END <32 get object_key >32 sending key object_key >32 END <32 set key 0 0 6 >32 STORED <32 incr key 1 >32 789544 <32 decr key 1 >32 789543 <32 incr key 2 >32 789545 <32 set my_key 0 0 10 >32 STORED <32 set object_key 1 0 36 >32 STORED <32 get my_key >32 sending key my_key >32 END <32 get object_key >32 sending key object_key1 1 36 >32 END <32 set key 0 0 6 >32 STORED <32 incr key 1 >32 789544 <32 decr key 1 >32 789543 <32 incr key 2 >32 789545 During client communication, for each line, the initial character shows the direction of flow of the information. The < for communication from the client to the `memcached' server and > for communication back to the client. The number is the numeric socket descriptor for the connection. * *Output when using `-vvv'* This level of verbosity includes the transitions of connections between different states in the event library while reading and writing content to/from the clients. It should be used to diagnose and identify issues in client communication. For example, you can use this information to determine if `memcached' is taking a long time to return information to the client, during the read of the client operation or before returning and completing the operation. An example of the typical sequence for a set operation is provided below: <32 new auto-negotiating client connection 32: going from conn_new_cmd to conn_waiting 32: going from conn_waiting to conn_read 32: going from conn_read to conn_parse_cmd 32: Client using the ascii protocol <32 set my_key 0 0 10 32: going from conn_parse_cmd to conn_nread > NOT FOUND my_key >32 STORED 32: going from conn_nread to conn_write 32: going from conn_write to conn_new_cmd 32: going from conn_new_cmd to conn_waiting 32: going from conn_waiting to conn_read 32: going from conn_read to conn_closing <32 connection closed. All of the verbosity levels in `memcached' are designed to be used during debugging or examination of issues. The quantity of information generated, particularly when using `-vvv', is significant, particularly on a busy server. Also be aware that writing the error information out, especially to disk, may negate some of the performance gains you achieve by using `memcached'. Therefore, use in production or deployment environments is not recommended.  File: manual.info, Node: ha-memcached-interfaces, Next: ha-memcached-stats, Prev: ha-memcached-using, Up: ha-memcached 15.6.3 `memcached' Interfaces ----------------------------- * Menu: * ha-memcached-interfaces-libmemcached:: Using `libmemcached' * ha-memcached-interfaces-perl:: Using MySQL and `memcached' with Perl * ha-memcached-interfaces-python:: Using MySQL and `memcached' with Python * ha-memcached-interfaces-php:: Using MySQL and `memcached' with PHP * ha-memcached-interfaces-ruby:: Using MySQL and `memcached' with Ruby * ha-memcached-interfaces-java:: Using MySQL and `memcached' with Java * ha-memcached-interfaces-mysqludf:: Using the MySQL `memcached' UDFs * ha-memcached-interfaces-protocol:: `memcached' Protocol A number of interfaces from different languages exist for interacting with `memcached' servers and storing and retrieving information. Interfaces for the most common language platforms including Perl, PHP, Python, Ruby, C and Java. Data stored into a `memcached' server is referred to by a single string (the key), with storage into the cache and retrieval from the cache using the key as the reference. The cache therefore operates like a large associative array or hash. It is not possible to structure or otherwise organize the information stored in the cache. If you want to store information in a structured way, you must use 'formatted' keys. The following tips may be useful to you when using `memcached': The general sequence for using `memcached' in any language as a caching solution is as follows: 1. Request the item from the cache. 2. If the item exists, use the item data. 3. If the item does not exist, load the data from MySQL, and store the value into the cache. This means the value is available to the next client that requests it from the cache. For a flow diagram of this sequence, see *Note ha-memcached-fig-basicflow::. FIGURE GOES HERE: Typical `memcached' Application Flowchart The interface to `memcached' supports the following methods for storing and retrieving information in the cache, and these are consistent across all the different APIs, even though the language specific mechanics may be different: * `get(key)': Retrieves information from the cache. Returns the value if it exists, or `NULL', `nil', or `undefined' or the closest equivalent in the corresponding language, if the specified key does not exist. * `set(key, value [, expiry])': Sets the key in the cache to the specified value. Note that this either updates an existing key if it already exists, or adds a new key/value pair if the key doesn't exist. If the expiry time is specified, then the key expires (and is deleted) when the expiry time is reached. The time is specified in seconds, and is taken as a relative time if the value is less than 30 days (30*24*60*60), or an absolute time (epoch) if larger than this value. * `add(key, value [, expiry])': Adds the key to the cache, if the specified key doesn't already exist. * `replace(key, value [, expiry])': Replaces the `value' of the specified `key', only if the key already exists. * `delete(key [, time])': Deletes the `key' from the cache. If you supply a `time', then adding a value with the specified `key' is blocked for the specified period. * `incr(key [, value])': Increments the specified `key' by one or the specified `value'. * `decr(key [, value])': Decrements the specified `key' by one or the specified `value'. * `flush_all': Invalidates (or expires) all the current items in the cache. Technically they still exist (they are not deleted), but they are silently destroyed the next time you try to access them. In all implementations, most or all of these functions are duplicated through the corresponding native language interface. For all languages and interfaces, use `memcached' to store full items, rather than simply caching single rows of information from the database. For example, when displaying a record about an object (invoice, user history, or blog post), load all the data for the associated entry from the database, and compile it into the internal structure that would normally be required by the application. You then save the complete object into the cache. Complex data structures cannot be stored directly. Most interfaces serialize the data for you, that is, put it in a form that can reconstruct the original pointers and nesting. Perl uses `Storable', PHP uses `serialize', Python uses `cPickle' (or `Pickle') and Java uses the `Serializable' interface. In most cases, the serialization interface used is customizable. To share data stored in `memcached' instances between different language interfaces, consider using a common serialization solution such as JSON (Javascript Object Notation).  File: manual.info, Node: ha-memcached-interfaces-libmemcached, Next: ha-memcached-interfaces-perl, Prev: ha-memcached-interfaces, Up: ha-memcached-interfaces 15.6.3.1 Using `libmemcached' ............................. * Menu: * ha-memcached-interfaces-libmemcached-base:: `libmemcached' Base Functions * ha-memcached-interfaces-libmemcached-servers:: `libmemcached' Server Functions * ha-memcached-interfaces-libmemcached-set:: `libmemcached' Set Functions * ha-memcached-interfaces-libmemcached-get:: `libmemcached' Get Functions * ha-memcached-interfaces-libmemcached-behaviors:: `libmemcached' Behaviors * ha-memcached-interfaces-libmemcached-utilities:: `libmemcached' Command-line Utilities The `libmemcached' library provides both C and C++ interfaces to `memcached' and is also the basis for a number of different additional API implementations, including Perl, Python and Ruby. Understanding the core `libmemcached' functions can help when using these other interfaces. The C library is the most comprehensive interface library for `memcached' and provides a wealth of functions and operational systems not always exposed in the other interfaces not based on the `libmemcached' library. The different functions can be divided up according to their basic operation. In addition to functions that interface to the core API, there are a number of utility functions that provide extended functionality, such as appending and prepending data. To build and install `libmemcached', download the `libmemcached' package, run configure, and then build and install: shell> tar xjf libmemcached-0.21.tar.gz shell> cd libmemcached-0.21 shell> ./configure shell> make shell> make install On many Linux operating systems, you can install the corresponding `libmemcached' package through the usual `yum', `apt-get' or similar commands. To build an application that uses the library, you need to first set the list of servers. You can do this either by directly manipulating the servers configured within the main `memcached_st' structure, or by separately populating a list of servers, and then adding this list to the `memcached_st' structure. The latter method is used in the following example. Once the server list has been set, you can call the functions to store or retrieve data. A simple application for setting a preset value to localhost is provided here: #include #include #include #include int main(int argc, char *argv[]) { memcached_server_st *servers = NULL; memcached_st *memc; memcached_return rc; char *key= "keystring"; char *value= "keyvalue"; memcached_server_st *memcached_servers_parse (char *server_strings); memc= memcached_create(NULL); servers= memcached_server_list_append(servers, "localhost", 11211, &rc); rc= memcached_server_push(memc, servers); if (rc == MEMCACHED_SUCCESS) fprintf(stderr,"Added server successfully\n"); else fprintf(stderr,"Couldn't add server: %s\n",memcached_strerror(memc, rc)); rc= memcached_set(memc, key, strlen(key), value, strlen(value), (time_t)0, (uint32_t)0); if (rc == MEMCACHED_SUCCESS) fprintf(stderr,"Key stored successfully\n"); else fprintf(stderr,"Couldn't store key: %s\n",memcached_strerror(memc, rc)); return 0; } You can test the success of an operation by using the return value, or populated result code, for a given function. The value is always set to `MEMCACHED_SUCCESS' if the operation succeeded. In the event of a failure, use the `memcached_strerror()' function to translate the result code into a printable string. To build the application, you must specify the `memcached' library: shell> gcc -o memc_basic memc_basic.c -lmemcached Running the above sample application, after starting a `memcached' server, should return a success message: shell> memc_basic Added server successfully Key stored successfully  File: manual.info, Node: ha-memcached-interfaces-libmemcached-base, Next: ha-memcached-interfaces-libmemcached-servers, Prev: ha-memcached-interfaces-libmemcached, Up: ha-memcached-interfaces-libmemcached 15.6.3.2 `libmemcached' Base Functions ...................................... The base `libmemcached' functions enable you to create, destroy and clone the main `memcached_st' structure that is used to interface to the `memcached' servers. The main functions are defined below: memcached_st *memcached_create (memcached_st *ptr); Creates a new `memcached_st' structure for use with the other `libmemcached' API functions. You can supply an existing, static, `memcached_st' structure, or `NULL' to have a new structured allocated. Returns a pointer to the created structure, or `NULL' on failure. void memcached_free (memcached_st *ptr); Free the structure and memory allocated to a previously created `memcached_st' structure. memcached_st *memcached_clone(memcached_st *clone, memcached_st *source); Clone an existing `memcached' structure from the specified `source', copying the defaults and list of servers defined in the structure.  File: manual.info, Node: ha-memcached-interfaces-libmemcached-servers, Next: ha-memcached-interfaces-libmemcached-set, Prev: ha-memcached-interfaces-libmemcached-base, Up: ha-memcached-interfaces-libmemcached 15.6.3.3 `libmemcached' Server Functions ........................................ The `libmemcached' API uses a list of servers, stored within the `memcached_server_st' structure, to act as the list of servers used by the rest of the functions. To use `memcached', you first create the server list, and then apply the list of servers to a valid `libmemcached' object. Because the list of servers, and the list of servers within an active `libmemcached' object can be manipulated separately, you can update and manage server lists while an active `libmemcached' interface is running. The functions for manipulating the list of servers within a `memcached_st' structure are given below: memcached_return memcached_server_add (memcached_st *ptr, char *hostname, unsigned int port); Add a server, using the given `hostname' and `port' into the `memcached_st' structure given in `ptr'. memcached_return memcached_server_add_unix_socket (memcached_st *ptr, char *socket); Add a Unix socket to the list of servers configured in the `memcached_st' structure. unsigned int memcached_server_count (memcached_st *ptr); Return a count of the number of configured servers within the `memcached_st' structure. memcached_server_st * memcached_server_list (memcached_st *ptr); Returns an array of all the defined hosts within a `memcached_st' structure. memcached_return memcached_server_push (memcached_st *ptr, memcached_server_st *list); Pushes an existing list of servers onto list of servers configured for a current `memcached_st' structure. This adds servers to the end of the existing list, and duplicates are not checked. The `memcached_server_st' structure can be used to create a list of `memcached' servers which can then be applied individually to `memcached_st' structures. memcached_server_st * memcached_server_list_append (memcached_server_st *ptr, char *hostname, unsigned int port, memcached_return *error); Add a server, with `hostname' and `port', to the server list in `ptr'. The result code is handled by the `error' argument, which should point to an existing `memcached_return' variable. The function returns a pointer to the returned list. unsigned int memcached_server_list_count (memcached_server_st *ptr); Return the number of the servers in the server list. void memcached_server_list_free (memcached_server_st *ptr); Free up the memory associated with a server list. memcached_server_st *memcached_servers_parse (char *server_strings); Parses a string containing a list of servers, where individual servers are separated by a comma, space, or both, and where individual servers are of the form `server[:port]'. The return value is a server list structure.  File: manual.info, Node: ha-memcached-interfaces-libmemcached-set, Next: ha-memcached-interfaces-libmemcached-get, Prev: ha-memcached-interfaces-libmemcached-servers, Up: ha-memcached-interfaces-libmemcached 15.6.3.4 `libmemcached' Set Functions ..................................... The set related functions within `libmemcached' provide the same functionality as the core functions supported by the `memcached' protocol. The full definition for the different functions is the same for all the base functions (add, replace, prepend, append). For example, the function definition for `memcached_set()' is: memcached_return memcached_set (memcached_st *ptr, const char *key, size_t key_length, const char *value, size_t value_length, time_t expiration, uint32_t flags); The `ptr' is the `memcached_st' structure. The `key' and `key_length' define the key name and length, and `value' and `value_length' the corresponding value and length. You can also set the expiration and optional flags. For more information, see *Note ha-memcached-interfaces-libmemcached-behaviors::. The following table outlines the remainder of the set-related functions. `libmemcached' Function Equivalent to `memcached_set(memc, key, Generic `set()' operation. key_length, value, value_length, expiration, flags)' `memcached_add(memc, key, Generic `add()' function. key_length, value, value_length, expiration, flags)' `memcached_replace(memc, key, Generic `replace()'. key_length, value, value_length, expiration, flags)' `memcached_prepend(memc, key, Prepends the specified `value' key_length, value, value_length, before the current value of the expiration, flags)' specified `key'. `memcached_append(memc, key, Appends the specified `value' after key_length, value, value_length, the current value of the specified expiration, flags)' `key'. `memcached_cas(memc, key, Overwrites the data for a given key key_length, value, value_length, as long as the corresponding `cas' expiration, flags, cas)' value is still the same within the server. `memcached_set_by_key(memc, Similar to the generic `set()', but master_key, master_key_length, key, has the option of an additional key_length, value, value_length, master key that can be used to expiration, flags)' identify an individual server. `memcached_add_by_key(memc, Similar to the generic `add()', but master_key, master_key_length, key, has the option of an additional key_length, value, value_length, master key that can be used to expiration, flags)' identify an individual server. `memcached_replace_by_key(memc, Similar to the generic `replace()', master_key, master_key_length, key, but has the option of an additional key_length, value, value_length, master key that can be used to expiration, flags)' identify an individual server. `memcached_prepend_by_key(memc, Similar to the master_key, master_key_length, key, `memcached_prepend()', but has the key_length, value, value_length, option of an additional master key expiration, flags)' that can be used to identify an individual server. `memcached_append_by_key(memc, Similar to the master_key, master_key_length, key, `memcached_append()', but has the key_length, value, value_length, option of an additional master key expiration, flags)' that can be used to identify an individual server. `memcached_cas_by_key(memc, Similar to the `memcached_cas()', master_key, master_key_length, key, but has the option of an additional key_length, value, value_length, master key that can be used to expiration, flags)' identify an individual server. The `by_key' methods add two further arguments, the master key, to be used and applied during the hashing stage for selecting the servers. You can see this in the following definition: memcached_return memcached_set_by_key(memcached_st *ptr, const char *master_key, size_t master_key_length, const char *key, size_t key_length, const char *value, size_t value_length, time_t expiration, uint32_t flags); All the functions return a value of type `memcached_return', which you can compare against the `MEMCACHED_SUCCESS' constant.  File: manual.info, Node: ha-memcached-interfaces-libmemcached-get, Next: ha-memcached-interfaces-libmemcached-behaviors, Prev: ha-memcached-interfaces-libmemcached-set, Up: ha-memcached-interfaces-libmemcached 15.6.3.5 `libmemcached' Get Functions ..................................... The `libmemcached' functions provide both direct access to a single item, and a multiple-key request mechanism that provides much faster responses when fetching a large number of keys simultaneously. The main get-style function, which is equivalent to the generic `get()' is `memcached_get()'. The functions a string pointer to the returned value for a corresponding key. char *memcached_get (memcached_st *ptr, const char *key, size_t key_length, size_t *value_length, uint32_t *flags, memcached_return *error); A multi-key get, `memcached_mget()', is also available. Using a multiple key get operation is much quicker to do in one block than retrieving the key values with individual calls to `memcached_get()'. To start the multi-key get, you need to call `memcached_mget()': memcached_return memcached_mget (memcached_st *ptr, char **keys, size_t *key_length, unsigned int number_of_keys); The return value is the success of the operation. The `keys' parameter should be an array of strings containing the keys, and `key_length' an array containing the length of each corresponding key. `number_of_keys' is the number of keys supplied in the array. To fetch the individual values, you need to use `memcached_fetch()' to get each corresponding value. char *memcached_fetch (memcached_st *ptr, const char *key, size_t *key_length, size_t *value_length, uint32_t *flags, memcached_return *error); The function returns the key value, with the `key', `key_length' and `value_length' parameters being populated with the corresponding key and length information. The function returns `NULL' when there are no more values to be returned. A full example, including the populating of the key data and the return of the information is provided here. #include #include #include #include int main(int argc, char *argv[]) { memcached_server_st *servers = NULL; memcached_st *memc; memcached_return rc; char *keys[]= {"huey", "dewey", "louie"}; size_t key_length[3]; char *values[]= {"red", "blue", "green"}; size_t value_length[3]; unsigned int x; uint32_t flags; char return_key[MEMCACHED_MAX_KEY]; size_t return_key_length; char *return_value; size_t return_value_length; memc= memcached_create(NULL); servers= memcached_server_list_append(servers, "localhost", 11211, &rc); rc= memcached_server_push(memc, servers); if (rc == MEMCACHED_SUCCESS) fprintf(stderr,"Added server successfully\n"); else fprintf(stderr,"Couldn't add server: %s\n",memcached_strerror(memc, rc)); for(x= 0; x < 3; x++) { key_length[x] = strlen(keys[x]); value_length[x] = strlen(values[x]); rc= memcached_set(memc, keys[x], key_length[x], values[x], value_length[x], (time_t)0, (uint32_t)0); if (rc == MEMCACHED_SUCCESS) fprintf(stderr,"Key %s stored successfully\n",keys[x]); else fprintf(stderr,"Couldn't store key: %s\n",memcached_strerror(memc, rc)); } rc= memcached_mget(memc, keys, key_length, 3); if (rc == MEMCACHED_SUCCESS) { while ((return_value= memcached_fetch(memc, return_key, &return_key_length, &return_value_length, &flags, &rc)) != NULL) { if (rc == MEMCACHED_SUCCESS) { fprintf(stderr,"Key %s returned %s\n",return_key, return_value); } } } return 0; } Running the above application: shell> memc_multi_fetch Added server successfully Key huey stored successfully Key dewey stored successfully Key louie stored successfully Key huey returned red Key dewey returned blue Key louie returned green  File: manual.info, Node: ha-memcached-interfaces-libmemcached-behaviors, Next: ha-memcached-interfaces-libmemcached-utilities, Prev: ha-memcached-interfaces-libmemcached-get, Up: ha-memcached-interfaces-libmemcached 15.6.3.6 `libmemcached' Behaviors ................................. The behavior of `libmemcached' can be modified by setting one or more behavior flags. These can either be set globally, or they can be applied during the call to individual functions. Some behaviors also accept an additional setting, such as the hashing mechanism used when selecting servers. To set global behaviors: memcached_return memcached_behavior_set (memcached_st *ptr, memcached_behavior flag, uint64_t data); To get the current behavior setting: uint64_t memcached_behavior_get (memcached_st *ptr, memcached_behavior flag); Behavior Description `MEMCACHED_BEHAVIOR_NO_BLOCK' Caused `libmemcached' to use asynchronous I/O. `MEMCACHED_BEHAVIOR_TCP_NODELAY'Turns on no-delay for network sockets. `MEMCACHED_BEHAVIOR_HASH' Without a value, sets the default hashing algorithm for keys to use MD5. Other valid values include `MEMCACHED_HASH_DEFAULT', `MEMCACHED_HASH_MD5', `MEMCACHED_HASH_CRC', `MEMCACHED_HASH_FNV1_64', `MEMCACHED_HASH_FNV1A_64', `MEMCACHED_HASH_FNV1_32', and `MEMCACHED_HASH_FNV1A_32'. `MEMCACHED_BEHAVIOR_DISTRIBUTION'Changes the method of selecting the server used to store a given value. The default method is `MEMCACHED_DISTRIBUTION_MODULA'. You can enable consistent hashing by setting `MEMCACHED_DISTRIBUTION_CONSISTENT'. `MEMCACHED_DISTRIBUTION_CONSISTENT' is an alias for the value `MEMCACHED_DISTRIBUTION_CONSISTENT_KETAMA'. `MEMCACHED_BEHAVIOR_CACHE_LOOKUPS'Cache the lookups made to the DNS service. This can improve the performance if you are using names instead of IP addresses for individual hosts. `MEMCACHED_BEHAVIOR_SUPPORT_CAS'Support CAS operations. By default, this is disabled because it imposes a performance penalty. `MEMCACHED_BEHAVIOR_KETAMA' Sets the default distribution to `MEMCACHED_DISTRIBUTION_CONSISTENT_KETAMA' and the hash to `MEMCACHED_HASH_MD5'. `MEMCACHED_BEHAVIOR_POLL_TIMEOUT'Modify the timeout value used by `poll()'. Supply a `signed int' pointer for the timeout value. `MEMCACHED_BEHAVIOR_BUFFER_REQUESTS'Buffers IO requests instead of them being sent. A get operation, or closing the connection causes the data to be flushed. `MEMCACHED_BEHAVIOR_VERIFY_KEY'Forces `libmemcached' to verify that a specified key is valid. `MEMCACHED_BEHAVIOR_SORT_HOSTS'If set, hosts added to the list of configured hosts for a `memcached_st' structure are placed into the host list in sorted order. This breaks consistent hashing if that behavior has been enabled. `MEMCACHED_BEHAVIOR_CONNECT_TIMEOUT'In nonblocking mode this changes the value of the timeout during socket connection.  File: manual.info, Node: ha-memcached-interfaces-libmemcached-utilities, Prev: ha-memcached-interfaces-libmemcached-behaviors, Up: ha-memcached-interfaces-libmemcached 15.6.3.7 `libmemcached' Command-line Utilities .............................................. In addition to the main C library interface, `libmemcached' also includes a number of command line utilities that can be useful when working with and debugging `memcached' applications. All of the command line tools accept a number of arguments, the most critical of which is `servers', which specifies the list of servers to connect to when returning information. The main tools are: * `memcat': Display the value for each ID given on the command line: shell> memcat --servers=localhost hwkey Hello world * `memcp': Copy the contents of a file into the cache, using the file names as the key: shell> echo "Hello World" > hwkey shell> memcp --servers=localhost hwkey shell> memcat --servers=localhost hwkey Hello world * `memrm': Remove an item from the cache: shell> memcat --servers=localhost hwkey Hello world shell> memrm --servers=localhost hwkey shell> memcat --servers=localhost hwkey * `memslap': Test the load on one or more `memcached' servers, simulating get/set and multiple client operations. For example, you can simulate the load of 100 clients performing get operations: shell> memslap --servers=localhost --concurrency=100 --flush --test=get memslap --servers=localhost --concurrency=100 --flush --test=get Threads connecting to servers 100 Took 13.571 seconds to read data * `memflush': Flush (empty) the contents of the `memcached' cache. shell> memflush --servers=localhost  File: manual.info, Node: ha-memcached-interfaces-perl, Next: ha-memcached-interfaces-python, Prev: ha-memcached-interfaces-libmemcached, Up: ha-memcached-interfaces 15.6.3.8 Using MySQL and `memcached' with Perl .............................................. The `Cache::Memcached' module provides a native interface to the Memcache protocol, and provides support for the core functions offered by `memcached'. You should install the module using your hosts native package management system. Alternatively, you can install the module using `CPAN': root-shell> perl -MCPAN -e 'install Cache::Memcached' To use `memcached' from Perl through `Cache::Memcached' module, you first need to create a new `Cache::Memcached' object that defines the list of servers and other parameters for the connection. The only argument is a hash containing the options for the cache interface. For example, to create a new instance that uses three `memcached' servers: use Cache::Memcached; my $cache = new Cache::Memcached { 'servers' => [ '192.168.0.100:11211', '192.168.0.101:11211', '192.168.0.102:11211', ], }; *Note*: When using the `Cache::Memcached' interface with multiple servers, the API automatically performs certain operations across all the servers in the group. For example, getting statistical information through `Cache::Memcached' returns a hash that contains data on a host by host basis, as well as generalized statistics for all the servers in the group. You can set additional properties on the cache object instance when it is created by specifying the option as part of the option hash. Alternatively, you can use a corresponding method on the instance: * `servers' or method `set_servers()': Specifies the list of the servers to be used. The servers list should be a reference to an array of servers, with each element as the address and port number combination (separated by a colon). You can also specify a local connection through a UNIX socket (for example `/tmp/sock/memcached'). You can also specify the server with a weight (indicating how much more frequently the server should be used during hashing) by specifying an array reference with the `memcached' server instance and a weight number. Higher numbers give higher priority. * `compress_threshold' or method `set_compress_threshold()': Specifies the threshold when values are compressed. Values larger than the specified number are automatically compressed (using `zlib') during storage and retrieval. * `no_rehash' or method `set_norehash()': Disables finding a new server if the original choice is unavailable. * `readonly' or method `set_readonly()': Disables writes to the `memcached' servers. Once the `Cache::Memcached' object instance has been configured you can use the `set()' and `get()' methods to store and retrieve information from the `memcached' servers. Objects stored in the cache are automatically serialized and deserialized using the `Storable' module. The `Cache::Memcached' interface supports the following methods for storing/retrieving data, and relate to the generic methods as shown in the table. `Cache::Memcached' Function Equivalent to `get()' Generic `get()' `get_multi(keys)' Gets multiple `keys' from memcache using just one query. Returns a hash reference of key/value pairs. `set()' Generic `set()' `add()' Generic `add()' `replace()' Generic `replace()' `delete()' Generic `delete()' `incr()' Generic `incr()' `decr()' Generic `decr()' Below is a complete example for using `memcached' with Perl and the `Cache::Memcached' module: #!/usr/bin/perl use Cache::Memcached; use DBI; use Data::Dumper; # Configure the memcached server my $cache = new Cache::Memcached { 'servers' => [ 'localhost:11211', ], }; # Get the film name from the command line # memcached keys must not contain spaces, so create # a key name by replacing spaces with underscores my $filmname = shift or die "Must specify the film name\n"; my $filmkey = $filmname; $filmkey =~ s/ /_/; # Load the data from the cache my $filmdata = $cache->get($filmkey); # If the data wasn't in the cache, then we load it from the database if (!defined($filmdata)) { $filmdata = load_filmdata($filmname); if (defined($filmdata)) { # Set the data into the cache, using the key if ($cache->set($filmkey,$filmdata)) { print STDERR "Film data loaded from database and cached\n"; } else { print STDERR "Couldn't store to cache\n"; } } else { die "Couldn't find $filmname\n"; } } else { print STDERR "Film data loaded from Memcached\n"; } sub load_filmdata { my ($filmname) = @_; my $dsn = "DBI:mysql:database=sakila;host=localhost;port=3306"; $dbh = DBI->connect($dsn, 'sakila','password'); my ($filmbase) = $dbh->selectrow_hashref(sprintf('select * from film where title = %s', $dbh->quote($filmname))); if (!defined($filmname)) { return (undef); } $filmbase->{stars} = $dbh->selectall_arrayref(sprintf('select concat(first_name," ",last_name) ' . 'from film_actor left join (actor) ' . 'on (film_actor.actor_id = actor.actor_id) ' . ' where film_id=%s', $dbh->quote($filmbase->{film_id}))); return($filmbase); } The example uses the Sakila database, obtaining film data from the database and writing a composite record of the film and actors to memcache. When calling it for a film does not exist, you get this result: shell> memcached-sakila.pl "ROCK INSTINCT" Film data loaded from database and cached When accessing a film that has already been added to the cache: shell> memcached-sakila.pl "ROCK INSTINCT" Film data loaded from Memcached  File: manual.info, Node: ha-memcached-interfaces-python, Next: ha-memcached-interfaces-php, Prev: ha-memcached-interfaces-perl, Up: ha-memcached-interfaces 15.6.3.9 Using MySQL and `memcached' with Python ................................................ The Python `memcache' module interfaces to `memcached' servers, and is written in pure python (that is, without using one of the C APIs). You can download and install a copy from Python Memcached (http://www.tummy.com/Community/software/python-memcached/). To install, download the package and then run the Python installer: python setup.py install running install running bdist_egg running egg_info creating python_memcached.egg-info ... removing 'build/bdist.linux-x86_64/egg' (and everything under it) Processing python_memcached-1.43-py2.4.egg creating /usr/lib64/python2.4/site-packages/python_memcached-1.43-py2.4.egg Extracting python_memcached-1.43-py2.4.egg to /usr/lib64/python2.4/site-packages Adding python-memcached 1.43 to easy-install.pth file Installed /usr/lib64/python2.4/site-packages/python_memcached-1.43-py2.4.egg Processing dependencies for python-memcached==1.43 Finished processing dependencies for python-memcached==1.43 Once installed, the `memcache' module provides a class-based interface to your `memcached' servers. Serialization of Python structures is handled by using the Python `cPickle' or `pickle' modules. To create a new `memcache' interface, import the `memcache' module and create a new instance of the `memcache.Client' class: import memcache memc = memcache.Client(['127.0.0.1:11211']) The first argument should be an array of strings containing the server and port number for each `memcached' instance you want to use. You can enable debugging by setting the optional `debug' parameter to 1. By default, the hashing mechanism used is `crc32'. This provides a basic module hashing algorithm for selecting among multiple servers. You can change the function used by setting the value of `memcache.serverHashFunction' to the alternate function you want to use. For example: from zlib import adler32 memcache.serverHashFunction = adler32 Once you have defined the servers to use within the `memcache' instance, the core functions provide the same functionality as in the generic interface specification. A summary of the supported functions is provided in the following table. Python `memcache' Function Equivalent to `get()' Generic `get()' `get_multi(keys)' Gets multiple values from the supplied array of `keys'. Returns a hash reference of key/value pairs. `set()' Generic `set()' `set_multi(dict [, expiry [, Sets multiple key/value pairs from key_prefix]])' the supplied `dict'. `add()' Generic `add()' `replace()' Generic `replace()' `prepend(key, value [, expiry])' Prepends the supplied `value' to the value of the existing `key'. `append(key, value [, expiry[)' Appends the supplied `value' to the value of the existing `key'. `delete()' Generic `delete()' `delete_multi(keys [, expiry [, Deletes all the keys from the hash key_prefix]] )' matching each string in the array `keys'. `incr()' Generic `incr()' `decr()' Generic `decr()' *Note*: Within the Python `memcache' module, all the `*_multi()'functions support an optional `key_prefix' parameter. If supplied, then the string is used as a prefix to all key lookups. For example, if you call: memc.get_multi(['a','b'], key_prefix='users:') The function retrieves the keys `users:a' and `users:b' from the servers. An example showing the storage and retrieval of information to a `memcache' instance, loading the raw data from MySQL, is shown below: import sys import MySQLdb import memcache memc = memcache.Client(['127.0.0.1:11211'], debug=1); try: conn = MySQLdb.connect (host = "localhost", user = "sakila", passwd = "password", db = "sakila") except MySQLdb.Error, e: print "Error %d: %s" % (e.args[0], e.args[1]) sys.exit (1) popularfilms = memc.get('top5films') if not popularfilms: cursor = conn.cursor() cursor.execute('select film_id,title from film order by rental_rate desc limit 5') rows = cursor.fetchall() memc.set('top5films',rows,60) print "Updated memcached with MySQL data" else: print "Loaded data from memcached" for row in popularfilms: print "%s, %s" % (row[0], row[1]) When executed for the first time, the data is loaded from the MySQL database and stored to the `memcached' server. shell> python memc_python.py Updated memcached with MySQL data The data is automatically serialized using `cPickle'/`pickle'. This means when you load the data back from `memcached', you can use the object directly. In the example above, the information stored to `memcached' is in the form of rows from a Python DB cursor. When accessing the information (within the 60 second expiry time), the data is loaded from `memcached' and dumped: shell> python memc_python.py Loaded data from memcached 2, ACE GOLDFINGER 7, AIRPLANE SIERRA 8, AIRPORT POLLOCK 10, ALADDIN CALENDAR 13, ALI FOREVER The serialization and deserialization happens automatically, but be aware that serialization of Python data may be incompatible with other interfaces and languages. You can change the serialization module used during initialization, for example to use JSON, which is more easily exchanged.  File: manual.info, Node: ha-memcached-interfaces-php, Next: ha-memcached-interfaces-ruby, Prev: ha-memcached-interfaces-python, Up: ha-memcached-interfaces 15.6.3.10 Using MySQL and `memcached' with PHP .............................................. PHP provides support for the Memcache functions through a PECL extension. To enable the PHP `memcache' extensions, you must build PHP using the `--enable-memcache' option to `configure' when building from source. If you are installing on a Red Hat based server, you can install the `php-pecl-memcache' RPM: root-shell> yum --install php-pecl-memcache On Debian based distributions, use the `php-memcache' package. You can set global runtime configuration options by specifying the values in the following table within your `php.ini' file. Configuration option Default Description `memcache.allow_failover' 1 Specifies whether another server in the list should be queried if the first server selected fails. `memcache.max_failover_attempts'20 Specifies the number of servers to try before returning a failure. `memcache.chunk_size' 8192 Defines the size of network chunks used to exchange data with the `memcached' server. `memcache.default_port' 11211 Defines the default port to use when communicating with the `memcached' servers. `memcache.hash_strategy' standard Specifies which hash strategy to use. Set to `consistent' to enable servers to be added or removed from the pool without causing the keys to be remapped to other servers. When set to `standard', an older (modula) strategy is used that potentially uses different servers for storage. `memcache.hash_function' crc32 Specifies which function to use when mapping keys to servers. `crc32' uses the standard CRC32 hash. `fnv' uses the FNV-1a hashing algorithm. To create a connection to a `memcached' server, you need to create a new `Memcache' object and then specifying the connection options. For example: connect('localhost',11211); ?> This opens an immediate connection to the specified server. To use multiple `memcached' servers, you need to add servers to the memcache object using `addServer()': bool Memcache::addServer ( string $host [, int $port [, bool $persistent [, int $weight [, int $timeout [, int $retry_interval [, bool $status [, callback $failure_callback ]]]]]]] ) The server management mechanism within the `php-memcache' module is a critical part of the interface as it controls the main interface to the `memcached' instances and how the different instances are selected through the hashing mechanism. To create a simple connection to two `memcached' instances: addServer('192.168.0.100',11211); $cache->addServer('192.168.0.101',11211); ?> In this scenario the instance connection is not explicitly opened, but only opened when you try to store or retrieve a value. You can enable persistent connections to `memcached' instances by setting the `$persistent' argument to true. This is the default setting, and causes the connections to remain open. To help control the distribution of keys to different instances, use the global `memcache.hash_strategy' setting. This sets the hashing mechanism used to select. You can also add another weight to each server, which effectively increases the number of times the instance entry appears in the instance list, therefore increasing the likelihood of the instance being chosen over other instances. To set the weight, set the value of the `$weight' argument to more than one. The functions for setting and retrieving information are identical to the generic functional interface offered by `memcached', as shown in this table. PECL `memcache' Function Equivalent to `get()' Generic `get()' `set()' Generic `set()' `add()' Generic `add()' `replace()' Generic `replace()' `delete()' Generic `delete()' `increment()' Generic `incr()' `decrement()' Generic `decr()' A full example of the PECL `memcache' interface is provided below. The code loads film data from the Sakila database when the user provides a film name. The data stored into the `memcached' instance is recorded as a `mysqli' result row, and the API automatically serializes the information for you. addServer('localhost','11211'); ?> Simple Memcache Lookup

Film:

get($_REQUEST['film']); if ($value) { printf("

Film data for %s loaded from memcache

",$value['title']); foreach (array_keys($value) as $key) { printf("

%s: %s

",$key, $value[$key]); } } else { $con = new mysqli('localhost','sakila','password','sakila') or die ("

Database problem

" . mysqli_connect_error()); $result = $con->query(sprintf('select * from film where title ="%s"',$_REQUEST['film'])); $row = $result->fetch_array(MYSQLI_ASSOC); $memc->set($row['title'],$row); printf("

Loaded %s from MySQL

",$row['title']); } ?> With PHP, the connections to the `memcached' instances are kept open as long as the PHP and associated Apache instance remain running. When adding a removing servers from the list in a running instance (for example, when starting another script that mentions additional servers), the connections are shared, but the script only selects among the instances explicitly configured within the script. To ensure that changes to the server list within a script do not cause problems, make sure to use the consistent hashing mechanism.  File: manual.info, Node: ha-memcached-interfaces-ruby, Next: ha-memcached-interfaces-java, Prev: ha-memcached-interfaces-php, Up: ha-memcached-interfaces 15.6.3.11 Using MySQL and `memcached' with Ruby ............................................... There are a number of different modules for interfacing to `memcached' within Ruby. The `Ruby-MemCache' client library provides a native interface to `memcached' that does not require any external libraries, such as `libmemcached'. You can obtain the installer package from `http://www.deveiate.org/projects/RMemCache'. To install, extract the package and then run `install.rb': shell> install.rb If you have RubyGems, you can install the `Ruby-MemCache' gem: shell> gem install Ruby-MemCache Bulk updating Gem source index for: http://gems.rubyforge.org Install required dependency io-reactor? [Yn] y Successfully installed Ruby-MemCache-0.0.1 Successfully installed io-reactor-0.05 Installing ri documentation for io-reactor-0.05... Installing RDoc documentation for io-reactor-0.05... To use a `memcached' instance from within Ruby, create a new instance of the `MemCache' object. require 'memcache' memc = MemCache::new '192.168.0.100:11211' You can add a weight to each server to increase the likelihood of the server being selected during hashing by appending the weight count to the server host name/port string: require 'memcache' memc = MemCache::new '192.168.0.100:11211:3' To add servers to an existing list, you can append them directly to the `MemCache' object: memc += ["192.168.0.101:11211"] To set data into the cache, you can just assign a value to a key within the new cache object, which works just like a standard Ruby hash object: memc["key"] = "value" Or to retrieve the value: print memc["key"] For more explicit actions, you can use the method interface, which mimics the main `memcached' API functions, as summarized in the following table. Ruby `MemCache' Method Equivalent to `get()' Generic `get()' `get_hash(keys)' Get the values of multiple `keys', returning the information as a hash of the keys and their values. `set()' Generic `set()' `set_many(pairs)' Set the values of the keys and values in the hash `pairs'. `add()' Generic `add()' `replace()' Generic `replace()' `delete()' Generic `delete()' `incr()' Generic `incr()' `decr()' Generic `decr()'  File: manual.info, Node: ha-memcached-interfaces-java, Next: ha-memcached-interfaces-mysqludf, Prev: ha-memcached-interfaces-ruby, Up: ha-memcached-interfaces 15.6.3.12 Using MySQL and `memcached' with Java ............................................... The `com.danga.MemCached' class within Java provides a native interface to `memcached' instances. You can obtain the client from `http://whalin.com/memcached/'. The Java class uses hashes that are compatible with `libmemcached', so you can mix and match Java and `libmemcached' applications accessing the same `memcached' instances. The serialization between Java and other interfaces are not compatible. If this is a problem, use JSON or a similar nonbinary serialization format. On most systems you can download the package and use the `jar' directly. To use the `com.danga.MemCached' interface, you create a `MemCachedClient' instance and then configure the list of servers by configuring the `SockIOPool'. Through the pool specification you set up the server list, weighting, and the connection parameters to optimized the connections between your client and the `memcached' instances that you configure. Generally you can configure the `memcached' interface once within a single class and then use this interface throughout the rest of your application. For example, to create a basic interface, first configure the `MemCachedClient' and base `SockIOPool' settings: public class MyClass { protected static MemCachedClient mcc = new MemCachedClient(); static { String[] servers = { "localhost:11211", }; Integer[] weights = { 1 }; SockIOPool pool = SockIOPool.getInstance(); pool.setServers( servers ); pool.setWeights( weights ); In the above sample, the list of servers is configured by creating an array of the `memcached' instances that you want to use. You can then configure individual weights for each server. The remainder of the properties for the connection are optional, but you can set the connection numbers (initial connections, minimum connections, maximum connections, and the idle timeout) by setting the pool parameters: pool.setInitConn( 5 ); pool.setMinConn( 5 ); pool.setMaxConn( 250 ); pool.setMaxIdle( 1000 * 60 * 60 * 6 Once the parameters have been configured, initialize the connection pool: pool.initialize(); The pool, and the connection to your `memcached' instances should now be ready to use. To set the hashing algorithm used to select the server used when storing a given key you can use `pool.setHashingAlg()': pool.setHashingAlg( SockIOPool.NEW_COMPAT_HASH ); Valid values are `NEW_COMPAT_HASH', `OLD_COMPAT_HASH' and `NATIVE_HASH' are also basic modula hashing algorithms. For a consistent hashing algorithm, use `CONSISTENT_HASH'. These constants are equivalent to the corresponding hash settings within `libmemcached'. Java `com.danga.MemCached' Method Equivalent to `get()' Generic `get()' `getMulti(keys)' Get the values of multiple `keys', returning the information as Hash map using `java.lang.String' for the keys and `java.lang.Object' for the corresponding values. `set()' Generic `set()' `add()' Generic `add()' `replace()' Generic `replace()' `delete()' Generic `delete()' `incr()' Generic `incr()' `decr()' Generic `decr()'  File: manual.info, Node: ha-memcached-interfaces-mysqludf, Next: ha-memcached-interfaces-protocol, Prev: ha-memcached-interfaces-java, Up: ha-memcached-interfaces 15.6.3.13 Using the MySQL `memcached' UDFs .......................................... The `memcached' MySQL User Defined Functions (UDFs) enable you to set and retrieve objects from within MySQL 5.0 or greater. To install the MySQL `memcached' UDFs, download the UDF package from `http://libmemcached.org/'. Unpack the package and run `configure' to configure the build process. When running `configure', use the `--with-mysql' option and specify the location of the *Note `mysql_config': mysql-config. command. shell> tar zxf memcached_functions_mysql-0.5.tar.gz shell> cd memcached_functions_mysql-0.5 shell> ./configure --with-mysql-config=/usr/local/mysql/bin/mysql_config Now build and install the functions: shell> make shell> make install Copy the MySQL `memcached' UDFs into your MySQL plugins directory: shell> cp /usr/local/lib/libmemcached_functions_mysql* /usr/local/mysql/lib/mysql/plugins/ The plugin directory is given by the value of the `plugin_dir' system variable. For more information, see *Note udf-compiling::. Once installed, you must initialize the function within MySQL using `CREATE' and specifying the return value and library. For example, to add the `memc_get()' function: mysql> CREATE FUNCTION memc_get RETURNS STRING SONAME "libmemcached_functions_mysql.so"; You must repeat this process for each function that you want to provide access to within MySQL. Once you have created the association, the information is retained, even over restarts of the MySQL server. You can simplify the process by using the SQL script provided in the `memcached' UDFs package: shell> mysql utils/install.pl --silent The `--silent' option installs everything automatically. Without this option, the script asks whether you want to install each of the available functions. The interface remains consistent with the other APIs and interfaces. To set up a list of servers, use the `memc_servers_set()' function, which accepts a single string containing and comma-separated list of servers: mysql> SELECT memc_servers_set('192.168.0.1:11211,192.168.0.2:11211'); *Note*: The list of servers used by the `memcached' UDFs is not persistent over restarts of the MySQL server. If the MySQL server fails, then you must re-set the list of `memcached' servers. To set a value, use `memc_set': mysql> SELECT memc_set('myid', 'myvalue'); To retrieve a stored value: mysql> SELECT memc_get('myid'); The list of functions supported by the UDFs, in relation to the standard protocol functions, is shown in the following table. MySQL `memcached' UDF Function Equivalent to `memc_get()' Generic `get()' `memc_get_by_key(master_key, key, Like the generic `get()', but uses value)' the supplied master key to select the server to use. `memc_set()' Generic `set()' `memc_set_by_key(master_key, key, Like the generic `set()', but uses value)' the supplied master key to select the server to use. `memc_add()' Generic `add()' `memc_add_by_key(master_key, key, Like the generic `add()', but uses value)' the supplied master key to select the server to use. `memc_replace()' Generic `replace()' `memc_replace_by_key(master_key, Like the generic `replace()', but key, value)' uses the supplied master key to select the server to use. `memc_prepend(key, value)' Prepend the specified `value' to the current value of the specified `key'. `memc_prepend_by_key(master_key, Prepend the specified `value' to key, value)' the current value of the specified `key', but uses the supplied master key to select the server to use. `memc_append(key, value)' Append the specified `value' to the current value of the specified `key'. `memc_append_by_key(master_key, Append the specified `value' to the key, value)' current value of the specified `key', but uses the supplied master key to select the server to use. `memc_delete()' Generic `delete()' `memc_delete_by_key(master_key, Like the generic `delete()', but key, value)' uses the supplied master key to select the server to use. `memc_increment()' Generic `incr()' `memc_decrement()' Generic `decr()' The respective `*_by_key()' functions are useful when you want to store a specific value into a specific `memcached' server, possibly based on a differently calculated or constructed key. The `memcached' UDFs include some additional functions: * `memc_server_count()' Returns a count of the number of servers in the list of registered servers. * `memc_servers_set_behavior(behavior_type, value)', `memc_set_behavior(behavior_type, value)' Set behaviors for the list of servers. These behaviors are identical to those provided by the `libmemcached' library. For more information on `libmemcached' behaviors, see *Note ha-memcached-interfaces-libmemcached::. You can use the behavior name as the `behavior_type': mysql> SELECT memc_servers_behavior_set("MEMCACHED_BEHAVIOR_KETAMA",1); * `memc_servers_behavior_get(behavior_type)', `memc_get_behavior(behavior_type, value)' Returns the value for a given behavior. * `memc_list_behaviors()' Returns a list of the known behaviors. * `memc_list_hash_types()' Returns a list of the supported key-hashing algorithms. * `memc_list_distribution_types()' Returns a list of the supported distribution types to be used when selecting a server to use when storing a particular key. * `memc_libmemcached_version()' Returns the version of the `libmemcached' library. * `memc_stats()' Returns the general statistics information from the server.  File: manual.info, Node: ha-memcached-interfaces-protocol, Prev: ha-memcached-interfaces-mysqludf, Up: ha-memcached-interfaces 15.6.3.14 `memcached' Protocol .............................. * Menu: * ha-memcached-interfaces-protocol-tcp:: Using the TCP text protocol Communicating with a `memcached' server can be achieved through either the TCP or UDP protocols. When using the TCP protocol you can use a simple text based interface for the exchange of information.  File: manual.info, Node: ha-memcached-interfaces-protocol-tcp, Prev: ha-memcached-interfaces-protocol, Up: ha-memcached-interfaces-protocol 15.6.3.15 Using the TCP text protocol ..................................... When communicating with `memcached' you can connect to the server using the port configured for the server. You can open a connection with the server without requiring authorization or login. As soon as you have connected, you can start to send commands to the server. When you have finished, you can terminate the connection without sending any specific disconnection command. Clients are encouraged to keep their connections open to decrease latency and improve performance. Data is sent to the `memcached' server in two forms: * Text lines, which are used to send commands to the server, and receive responses from the server. * Unstructured data, which is used to receive or send the value information for a given key. Data is returned to the client in exactly the format it was provided. Both text lines (commands and responses) and unstructured data are always terminated with the string `\r\n'. Because the data being stored may contain this sequence, the length of the data (returned by the client before the unstructured data is transmitted should be used to determine the end of the data. Commands to the server are structured according to their operation: * *Storage commands*: `set', `add', `replace', `append', `prepend', `cas' Storage commands to the server take the form: command key [flags] [exptime] length [noreply] Or when using compare and swap (cas): cas key [flags] [exptime] length [casunique] [noreply] Where: * `command': The command name. * `set': Store value against key * `add': Store this value against key if the key does not already exist * `replace': Store this value against key if the key already exists * `append': Append the supplied value to the end of the value for the specified key. The `flags' and `exptime' arguments should not be used. * `prepend': Append value currently in the cache to the end of the supplied value for the specified key. The `flags' and `exptime' arguments should not be used. * `cas': Set the specified key to the supplied value, only if the supplied `casunique' matches. This is effectively the equivalent of change the information if nobody has updated it since I last fetched it. * `key': The key. All data is stored using a the specific key. The key cannot contain control characters or whitespace, and can be up to 250 characters in size. * `flags': The flags for the operation (as an integer). Flags in `memcached' are transparent. The `memcached' server ignores the contents of the flags. They can be used by the client to indicate any type of information. In `memcached' 1.2.0 and lower the value is a 16-bit integer value. In `memcached' 1.2.1 and higher the value is a 32-bit integer. * `exptime': The expiry time, or zero for no expiry. * `length': The length of the supplied value block in bytes, excluding the terminating `\r\n' characters. * `casunique': A unique 64-bit value of an existing entry. This is used to compare against the existing value. Use the value returned by the `gets' command when issuing `cas' updates. * `noreply': Tells the server not to reply to the command. For example, to store the value `abcdef' into the key `xyzkey', you would use: set xyzkey 0 0 6\r\nabcdef\r\n The return value from the server is one line, specifying the status or error information. For more information, see *Note ha-memcached-interfaces-protocol-responses::. * *Retrieval commands*: `get', `gets' Retrieval commands take the form: get key1 [key2 .... keyn] gets key1 [key2 ... keyn] You can supply multiple keys to the commands, with each requested key separated by whitespace. The server responds with an information line of the form: VALUE key flags bytes [casunique] Where: * `key': The key name. * `flags': The value of the flag integer supplied to the `memcached' server when the value was stored. * `bytes': The size (excluding the terminating `\r\n' character sequence) of the stored value. * `casunique': The unique 64-bit integer that identifies the item. The information line is immediately followed by the value data block. For example: get xyzkey\r\n VALUE xyzkey 0 6\r\n abcdef\r\n If you have requested multiple keys, an information line and data block is returned for each key found. If a requested key does not exist in the cache, no information is returned. * *Delete commands*: `delete' Deletion commands take the form: delete key [time] [noreply] Where: * `key': The key name. * `time': The time in seconds (or a specific Unix time) for which the client wishes the server to refuse `add' or `replace' commands on this key. All `add', `replace', `get', and `gets' commands fail during this period. `set' operations succeed. After this period, the key is deleted permanently and all commands are accepted. If not supplied, the value is assumed to be zero (delete immediately). * `noreply': Tells the server not to reply to the command. Responses to the command are either `DELETED' to indicate that the key was successfully removed, or `NOT_FOUND' to indicate that the specified key could not be found. * *Increment/Decrement*: `incr', `decr' The increment and decrement commands change the value of a key within the server without performing a separate get/set sequence. The operations assume that the currently stored value is a 64-bit integer. If the stored value is not a 64-bit integer, then the value is assumed to be zero before the increment or decrement operation is applied. Increment and decrement commands take the form: incr key value [noreply] decr key value [noreply] Where: * `key': The key name. * `value': An integer to be used as the increment or decrement value. * `noreply': Tells the server not to reply to the command. The response is: * `NOT_FOUND': The specified key could not be located. * `value': The new value of the specified key. Values are assumed to be unsigned. For `decr' operations the value is never decremented below 0. For `incr' operations, the value wraps around the 64-bit maximum. * *Statistics commands*: `stats' The `stats' command provides detailed statistical information about the current status of the `memcached' instance and the data it is storing. Statistics commands take the form: STAT [name] [value] Where: * `name': The optional name of the statistics to return. If not specified, the general statistics are returned. * `value': A specific value to be used when performing certain statistics operations. The return value is a list of statistics data, formatted as follows: STAT name value The statistics are terminated with a single line, `END'. For more information, see *Note ha-memcached-stats::. For reference, a list of the different commands supported and their formats is provided below. *`memcached' Command Reference* Command Command Formats `set' `set key flags exptime length', `set key flags exptime length noreply' `add' `add key flags exptime length', `add key flags exptime length noreply' `replace' `replace key flags exptime length', `replace key flags exptime length noreply' `append' `append key length', `append key length noreply' `prepend' `prepend key length', `prepend key length noreply' `cas' `cas key flags exptime length casunique', `cas key flags exptime length casunique noreply' `get' `get key1 [key2 ... keyn]' `gets' `' `delete' `delete key', `delete key noreply', `delete key expiry', `delete key expiry noreply' `incr' `incr key', `incr key noreply', `incr key value', `incr key value noreply' `decr' `decr key', `decr key noreply', `decr key value', `decr key value noreply' `stat' `stat', `stat name', `stat name value' When sending a command to the server, the response from the server is one of the settings in the following table. All response values from the server are terminated by `\r\n': *`memcached' Protocol Responses* String Description `STORED' Value has successfully been stored. `NOT_STORED' The value was not stored, but not because of an error. For commands where you are adding a or updating a value if it exists (such as `add' and `replace'), or where the item has already been set to be deleted. `EXISTS' When using a `cas' command, the item you are trying to store already exists and has been modified since you last checked it. `NOT_FOUND' The item you are trying to store, update or delete does not exist or has already been deleted. `ERROR' You submitted a nonexistent command name. `CLIENT_ERROR There was an error in the input line, the detail is errorstring' contained in `errorstring'. `SERVER_ERROR There was an error in the server that prevents it errorstring' from returning the information. In extreme conditions, the server may disconnect the client after this error occurs. `VALUE keys flags The requested key has been found, and the stored length' `key', `flags' and data block are returned, of the specified `length'. `DELETED' The requested key was deleted from the server. `STAT name value' A line of statistics data. `END' The end of the statistics data.  File: manual.info, Node: ha-memcached-stats, Next: ha-memcached-faq, Prev: ha-memcached-interfaces, Up: ha-memcached 15.6.4 Getting `memcached' Statistics ------------------------------------- * Menu: * ha-memcached-stats-general:: `memcached' General Statistics * ha-memcached-stats-slabs:: `memcached' Slabs Statistics * ha-memcached-stats-items:: `memcached' Item Statistics * ha-memcached-stats-sizes:: `memcached' Size Statistics * ha-memcached-stats-detail:: `memcached' Detail Statistics * ha-memcached-stats-memcached-tool:: Using `memcached-tool' The `memcached' system has a built in statistics system that collects information about the data being stored into the cache, cache hit ratios, and detailed information on the memory usage and distribution of information through the slab allocation used to store individual items. Statistics are provided at both a basic level that provide the core statistics, and more specific statistics for specific areas of the `memcached' server. This information can prove be very useful to ensure that you are getting the correct level of cache and memory usage, and that your slab allocation and configuration properties are set at an optimal level. The stats interface is available through the standard `memcached' protocol, so the reports can be accessed by using `telnet' to connect to the `memcached'. The supplied `memcached-tool' includes support for obtaining the *Note ha-memcached-stats-slabs:: and *Note ha-memcached-stats-general:: information. For more information, see *Note ha-memcached-stats-memcached-tool::. Alternatively, most of the language API interfaces provide a function for obtaining the statistics from the server. For example, to get the basic stats using `telnet': shell> telnet localhost 11211 Trying ::1... Connected to localhost. Escape character is '^]'. stats STAT pid 23599 STAT uptime 675 STAT time 1211439587 STAT version 1.2.5 STAT pointer_size 32 STAT rusage_user 1.404992 STAT rusage_system 4.694685 STAT curr_items 32 STAT total_items 56361 STAT bytes 2642 STAT curr_connections 53 STAT total_connections 438 STAT connection_structures 55 STAT cmd_get 113482 STAT cmd_set 80519 STAT get_hits 78926 STAT get_misses 34556 STAT evictions 0 STAT bytes_read 6379783 STAT bytes_written 4860179 STAT limit_maxbytes 67108864 STAT threads 1 END When using Perl and the `Cache::Memcached' module, the `stats()' function returns information about all the servers currently configured in the connection object, and total statistics for all the `memcached' servers as a whole. For example, the following Perl script obtains the stats and dumps the hash reference that is returned: use Cache::Memcached; use Data::Dumper; my $memc = new Cache::Memcached; $memc->set_servers(\@ARGV); print Dumper($memc->stats()); When executed on the same `memcached' as used in the `Telnet' example above we get a hash reference with the host by host and total statistics: $VAR1 = { 'hosts' => { 'localhost:11211' => { 'misc' => { 'bytes' => '2421', 'curr_connections' => '3', 'connection_structures' => '56', 'pointer_size' => '32', 'time' => '1211440166', 'total_items' => '410956', 'cmd_set' => '588167', 'bytes_written' => '35715151', 'evictions' => '0', 'curr_items' => '31', 'pid' => '23599', 'limit_maxbytes' => '67108864', 'uptime' => '1254', 'rusage_user' => '9.857805', 'cmd_get' => '838451', 'rusage_system' => '34.096988', 'version' => '1.2.5', 'get_hits' => '581511', 'bytes_read' => '46665716', 'threads' => '1', 'total_connections' => '3104', 'get_misses' => '256940' }, 'sizes' => { '128' => '16', '64' => '15' } } }, 'self' => {}, 'total' => { 'cmd_get' => 838451, 'bytes' => 2421, 'get_hits' => 581511, 'connection_structures' => 56, 'bytes_read' => 46665716, 'total_items' => 410956, 'total_connections' => 3104, 'cmd_set' => 588167, 'bytes_written' => 35715151, 'curr_items' => 31, 'get_misses' => 256940 } }; The statistics are divided up into a number of distinct sections, and then can be requested by adding the type to the `stats' command. Each statistics output is covered in more detail in the following sections. * General statistics, see *Note ha-memcached-stats-general::. * Slab statistics (`slabs'), see *Note ha-memcached-stats-slabs::. * Item statistics (`items'), see *Note ha-memcached-stats-items::. * Size statistics (`sizes'), see *Note ha-memcached-stats-sizes::. * Detailed status (`detail'), see *Note ha-memcached-stats-detail::.  File: manual.info, Node: ha-memcached-stats-general, Next: ha-memcached-stats-slabs, Prev: ha-memcached-stats, Up: ha-memcached-stats 15.6.4.1 `memcached' General Statistics ....................................... The output of the general statistics provides an overview of the performance and use of the `memcached' instance. The statistics returned by the command and their meaning is shown in the following table. The following terms are used to define the value type for each statistics value: * `32u': 32-bit unsigned integer * `64u': 64-bit unsigned integer * `32u32u': Two 32-bit unsigned integers separated by a colon * `String': Character string Statistic Data type Description Version pid 32u Process ID of the `memcached' instance. uptime 32u Uptime (in seconds) for this `memcached' instance. time 32u Current time (as epoch). version string Version string of this instance. pointer_size string Size of pointers for this host specified in bits (32 or 64). rusage_user 32u:32u Total user time for this instance (seconds:microseconds). rusage_system 32u:32u Total system time for this instance (seconds:microseconds). curr_items 32u Current number of items stored by this instance. total_items 32u Total number of items stored during the life of this instance. bytes 64u Current number of bytes used by this server to store items. curr_connections32u Current number of open connections. total_connections32u Total number of connections opened since the server started running. connection_structures32u Number of connection structures allocated by the server. cmd_get 64u Total number of retrieval requests (`get' operations). cmd_set 64u Total number of storage requests (`set' operations). get_hits 64u Number of keys that have been requested and found present. get_misses 64u Number of items that have been requested and not found. delete_hits 64u Number of keys that have been deleted 1.3.x and found present. delete_misses 64u Number of items that have been delete 1.3.x and not found. incr_hits 64u Number of keys that have been 1.3.x incremented and found present. incr_misses 64u Number of items that have been 1.3.x incremented and not found. decr_hits 64u Number of keys that have been 1.3.x decremented and found present. decr_misses 64u Number of items that have been 1.3.x decremented and not found. cas_hits 64u Number of keys that have been compared 1.3.x and swapped and found present. cas_misses 64u Number of items that have been compared 1.3.x and swapped and not found. cas_badvalue 64u Number of keys that have been compared 1.3.x and swapped, but the comparison (original) value did not match the supplied value. evictions 64u Number of valid items removed from cache to free memory for new items. bytes_read 64u Total number of bytes read by this server from network. bytes_written 64u Total number of bytes sent by this server to network. limit_maxbytes 32u Number of bytes this server is permitted to use for storage. threads 32u Number of worker threads requested. conn_yields 64u Number of yields for connections 1.4.0 (related to the `-R' option). The most useful statistics from those given here are the number of cache hits, misses, and evictions. A large number of `get_misses' may just be an indication that the cache is still being populated with information. The number should, over time, decrease in comparison to the number of cache `get_hits'. If, however, you have a large number of cache misses compared to cache hits after an extended period of execution, it may be an indication that the size of the cache is too small and you either need to increase the total memory size, or increase the number of the `memcached' instances to improve the hit ratio. A large number of `evictions' from the cache, particularly in comparison to the number of items stored is a sign that your cache is too small to hold the amount of information that you regularly want to keep cached. Instead of items being retained in the cache, items are being evicted to make way for new items keeping the turnover of items in the cache high, reducing the efficiency of the cache.  File: manual.info, Node: ha-memcached-stats-slabs, Next: ha-memcached-stats-items, Prev: ha-memcached-stats-general, Up: ha-memcached-stats 15.6.4.2 `memcached' Slabs Statistics ..................................... To get the `slabs' statistics, use the `stats slabs' command, or the API equivalent. The slab statistics provide you with information about the slabs that have created and allocated for storing information within the cache. You get information both on each individual slab-class and total statistics for the whole slab. STAT 1:chunk_size 104 STAT 1:chunks_per_page 10082 STAT 1:total_pages 1 STAT 1:total_chunks 10082 STAT 1:used_chunks 10081 STAT 1:free_chunks 1 STAT 1:free_chunks_end 10079 STAT 9:chunk_size 696 STAT 9:chunks_per_page 1506 STAT 9:total_pages 63 STAT 9:total_chunks 94878 STAT 9:used_chunks 94878 STAT 9:free_chunks 0 STAT 9:free_chunks_end 0 STAT active_slabs 2 STAT total_malloced 67083616 END Individual stats for each slab class are prefixed with the slab ID. A unique ID is given to each allocated slab from the smallest size up to the largest. The prefix number indicates the slab class number in relation to the calculated chunk from the specified growth factor. Hence in the example, 1 is the first chunk size and 9 is the 9th chunk allocated size. The different parameters returned for each chunk size and the totals are shown in the following table. Statistic Description Version chunk_size Space allocated to each chunk within this slab class. chunks_per_page Number of chunks within a single page for this slab class. total_pages Number of pages allocated to this slab class. total_chunks Number of chunks allocated to the slab class. used_chunks Number of chunks allocated to an item.. free_chunks Number of chunks not yet allocated to items. free_chunks_end Number of free chunks at the end of the last allocated page. get_hits Number of get hits to this chunk 1.3.x cmd_set Number of set commands on this chunk 1.3.x delete_hits Number of delete hits to this chunk 1.3.x incr_hits Number of increment hits to this chunk 1.3.x decr_hits Number of decrement hits to this chunk 1.3.x cas_hits Number of CAS hits to this chunk 1.3.x cas_badval Number of CAS hits on this chunk where 1.3.x the existing value did not match mem_requested The true amount of memory of memory 1.4.1 requested within this chunk The following additional statistics cover the information for the entire server, rather than on a chunk by chunk basis: Statistic Description Version active_slabs Total number of slab classes allocated. total_malloced Total amount of memory allocated to slab pages. The key values in the slab statistics are the `chunk_size', and the corresponding `total_chunks' and `used_chunks' parameters. These given an indication of the size usage of the chunks within the system. Remember that one key/value pair is placed into a chunk of a suitable size. From these stats, you can get an idea of your size and chunk allocation and distribution. If you store many items with a number of largely different sizes, then you may want to adjust the chunk size growth factor to increase in larger steps to prevent chunk and memory wastage. A good indication of a bad growth factor is a high number of different slab classes, but with relatively few chunks actually in use within each slab. Increasing the growth factor creates fewer slab classes and therefore makes better use of the allocated pages.  File: manual.info, Node: ha-memcached-stats-items, Next: ha-memcached-stats-sizes, Prev: ha-memcached-stats-slabs, Up: ha-memcached-stats 15.6.4.3 `memcached' Item Statistics .................................... To get the `items' statistics, use the `stats items' command, or the API equivalent. The `items' statistics give information about the individual items allocated within a given slab class. STAT items:2:number 1 STAT items:2:age 452 STAT items:2:evicted 0 STAT items:2:evicted_nonzero 0 STAT items:2:evicted_time 2 STAT items:2:outofmemory 0 STAT items:2:tailrepairs 0 ... STAT items:27:number 1 STAT items:27:age 452 STAT items:27:evicted 0 STAT items:27:evicted_nonzero 0 STAT items:27:evicted_time 2 STAT items:27:outofmemory 0 STAT items:27:tailrepairs 0 The prefix number against each statistics relates to the corresponding chunk size, as returned by the `stats slabs' statistics. The result is a display of the number of items stored within each chunk within each slab size, and specific statistics about their age, eviction counts, and out of memory counts. A summary of the statistics is given in the following table. Statistic Description `number' The number of items currently stored in this slab class. `age' The age of the oldest item within the slab class, in seconds. `evicted' The number of items evicted to make way for new entries. `evicted_time' The time of the last evicted entry `evicted_nonzero' The time of the last evicted non-zero entry 1.4.0 `outofmemory' The number of items for this slab class that have triggered an out of memory error (only value when the `-M' command line option is in effect). tailrepairs Number of times the entries for a particular ID need repairing Item level statistics can be used to determine how many items are stored within a given slab and their freshness and recycle rate. You can use this to help identify whether there are certain slab classes that are triggering a much larger number of evictions that others.  File: manual.info, Node: ha-memcached-stats-sizes, Next: ha-memcached-stats-detail, Prev: ha-memcached-stats-items, Up: ha-memcached-stats 15.6.4.4 `memcached' Size Statistics .................................... To get size statistics, use the `stats sizes' command, or the API equivalent. The size statistics provide information about the sizes and number of items of each size within the cache. The information is returned as two columns, the first column is the size of the item (rounded up to the nearest 32 byte boundary), and the second column is the count of the number of items of that size within the cache: 96 35 128 38 160 807 192 804 224 410 256 222 288 83 320 39 352 53 384 33 416 64 448 51 480 30 512 54 544 39 576 10065 *Caution*: Running this statistic locks up your cache as each item is read from the cache and its size calculated. On a large cache, this may take some time and prevent any set or get operations until the process completes. The item size statistics are useful only to determine the sizes of the objects you are storing. Since the actual memory allocation is relevant only in terms of the chunk size and page size, the information is only useful during a careful debugging or diagnostic session.  File: manual.info, Node: ha-memcached-stats-detail, Next: ha-memcached-stats-memcached-tool, Prev: ha-memcached-stats-sizes, Up: ha-memcached-stats 15.6.4.5 `memcached' Detail Statistics ...................................... For `memcached' 1.3.x and higher, you can enable and obtain detailed statistics about the get, set, and del operations on theindividual keys stored in the cache, and determine whether the attempts hit (found) a particular key. These operations are only recorded while the detailed stats analysis is turned on. To enable detailed statistics, you must send the `stats detail on' command to the `memcached' server: $ telnet localhost 11211 Trying 127.0.0.1... Connected to tiger. Escape character is '^]'. stats detail on OK Individual statistics are recorded for every `get', `set' and `del' operation on a key, including keys that are not currently stored in the server. For example, if an attempt is made to obtain the value of key `abckey' and it does not exist, the `get' operating on the specified key are recorded while detailed statistics are in effect, even if the key is not currently stored. The `hits', that is, the number of `get' or `del' operations for a key that exists in the server are also counted. To turn detailed statistics off, send the `stats detail off' command to the `memcached' server: $ telnet localhost 11211 Trying 127.0.0.1... Connected to tiger. Escape character is '^]'. stats detail on OK To obtain the detailed statistics recorded during the process, send the `stats detail dump' command to the `memcached' server: stats detail dump PREFIX hykkey get 0 hit 0 set 1 del 0 PREFIX xyzkey get 0 hit 0 set 1 del 0 PREFIX yukkey get 1 hit 0 set 0 del 0 PREFIX abckey get 3 hit 3 set 1 del 0 END You can use the detailed statistics information to determine whether your `memcached' clients are using a large number of keys that do not exist in the server by comparing the `hit' and `get' or `del' counts. Because the information is recorded by key, you can also determine whether the failures or operations are clustered around specific keys.  File: manual.info, Node: ha-memcached-stats-memcached-tool, Prev: ha-memcached-stats-detail, Up: ha-memcached-stats 15.6.4.6 Using `memcached-tool' ............................... The `memcached-tool', located within the `scripts' directory within the `memcached' source directory. The tool provides convenient access to some reports and statistics from any `memcached' instance. The basic format of the command is: shell> ./memcached-tool hostname:port [command] The default output produces a list of the slab allocations and usage. For example: shell> memcached-tool localhost:11211 display # Item_Size Max_age Pages Count Full? Evicted Evict_Time OOM 1 80B 93s 1 20 no 0 0 0 2 104B 93s 1 16 no 0 0 0 3 136B 1335s 1 28 no 0 0 0 4 176B 1335s 1 24 no 0 0 0 5 224B 1335s 1 32 no 0 0 0 6 280B 1335s 1 34 no 0 0 0 7 352B 1335s 1 36 no 0 0 0 8 440B 1335s 1 46 no 0 0 0 9 552B 1335s 1 58 no 0 0 0 10 696B 1335s 1 66 no 0 0 0 11 872B 1335s 1 89 no 0 0 0 12 1.1K 1335s 1 112 no 0 0 0 13 1.3K 1335s 1 145 no 0 0 0 14 1.7K 1335s 1 123 no 0 0 0 15 2.1K 1335s 1 198 no 0 0 0 16 2.6K 1335s 1 199 no 0 0 0 17 3.3K 1335s 1 229 no 0 0 0 18 4.1K 1335s 1 248 yes 36 2 0 19 5.2K 1335s 2 328 no 0 0 0 20 6.4K 1335s 2 316 yes 387 1 0 21 8.1K 1335s 3 381 yes 492 1 0 22 10.1K 1335s 3 303 yes 598 2 0 23 12.6K 1335s 5 405 yes 605 1 0 24 15.8K 1335s 6 384 yes 766 2 0 25 19.7K 1335s 7 357 yes 908 170 0 26 24.6K 1336s 7 287 yes 1012 1 0 27 30.8K 1336s 7 231 yes 1193 169 0 28 38.5K 1336s 4 104 yes 1323 169 0 29 48.1K 1336s 1 21 yes 1287 1 0 30 60.2K 1336s 1 17 yes 1093 169 0 31 75.2K 1337s 1 13 yes 713 168 0 32 94.0K 1337s 1 10 yes 278 168 0 33 117.5K 1336s 1 3 no 0 0 0 This output is the same if you specify the `command' as `display': shell> memcached-tool localhost:11211 display # Item_Size Max_age Pages Count Full? Evicted Evict_Time OOM 1 80B 93s 1 20 no 0 0 0 2 104B 93s 1 16 no 0 0 0 ... The output shows a summarized version of the output from the `slabs' statistics. The columns provided in the output are shown below: * `#': The slab number * `Item_Size': The size of the slab * `Max_age': The age of the oldest item in the slab * `Pages': The number of pages allocated to the slab * `Count': The number of items in this slab * `Full?': Whether the slab is fully populated * `Evicted': The number of objects evicted from this slab * `Evict_Time': The time (in seconds) since the last eviction * `OOM': The number of items that have triggered an out of memory error You can also obtain a dump of the general statistics for the server using the `stats' command: shell> memcached-tool localhost:11211 stats #localhost:11211 Field Value accepting_conns 1 bytes 162 bytes_read 485 bytes_written 6820 cas_badval 0 cas_hits 0 cas_misses 0 cmd_flush 0 cmd_get 4 cmd_set 2 conn_yields 0 connection_structures 11 curr_connections 10 curr_items 2 decr_hits 0 decr_misses 1 delete_hits 0 delete_misses 0 evictions 0 get_hits 4 get_misses 0 incr_hits 0 incr_misses 2 limit_maxbytes 67108864 listen_disabled_num 0 pid 12981 pointer_size 32 rusage_system 0.013911 rusage_user 0.011876 threads 4 time 1255518565 total_connections 20 total_items 2 uptime 880 version 1.4.2 The `memcached-tool' provides  File: manual.info, Node: ha-memcached-faq, Prev: ha-memcached-stats, Up: ha-memcached 15.6.5 `memcached' FAQ ---------------------- *Questions* * 15.6.5.1: Can MySQL actually trigger/store the changed data to memcached? * 15.6.5.2: Can memcached be run on a Windows environment? * 15.6.5.3: Does the `-L' flag automatically sense how much memory is being used by other memcached? * 15.6.5.4: What is the max size of an object you can store in memcache and is that configurable? * 15.6.5.5: Is it true `memcached' will be much more effective with db-read-intensive applications than with db-write-intensive applications? * 15.6.5.6: `memcached' is fast - is there any overhead in not using persistent connections? If persistent is always recommended, what are the downsides (for example, locking up)? * 15.6.5.7: How does an event such as a crash of one of the `memcached' servers handled by the `memcached' client? * 15.6.5.8: What's a recommended hardware config for a memcached server? Linux or Windows? * 15.6.5.9: Doing a direct telnet to the memcached port, is that just for that one machine, or does it magically apply across all nodes? * 15.6.5.10: Is memcached more effective for video and audio as opposed to textual read/writes * 15.6.5.11: If you log a complex class (with methods that do calculation etc) will the get from Memcache re-create the class on the way out? * 15.6.5.12: If I have an object larger then a MB, do I have to manually split it or can I configure `memcached' to handle larger objects? * 15.6.5.13: Can `memcached' work with `ASPX'? * 15.6.5.14: Are there any, or are there any plans to introduce, a framework to hide the interaction of memcached from the application; that is, within hibernate? * 15.6.5.15: So the responsibility lies with the application to populate and get records from the database as opposed to being a transparent cache layer for the db? * 15.6.5.16: How does `memcached' compare to nCache? * 15.6.5.17: We are caching XML by serialising using saveXML(), because PHP cannot serialize DOM objects; Some of the XML is variable and is modified per-request. Do you recommend caching then using XPath, or is it better to rebuild the DOM from separate node-groups? * 15.6.5.18: How easy is it to introduce `memcached' to an existing enterprise application instead of inclusion at project design? * 15.6.5.19: Do the memcache UDFs work under 5.1? * 15.6.5.20: Is the data inside of `memcached' secure? * 15.6.5.21: Is `memcached' typically a better solution for improving speed than MySQL Cluster and\or MySQL Proxy? * 15.6.5.22: File socket support for `memcached' from the localhost use to the local memcached server? * 15.6.5.23: How expensive is it to establish a memcache connection? Should those connections be pooled? * 15.6.5.24: What are the advantages of using UDFs when the get/sets are manageable from within the client code rather than the db? * 15.6.5.25: How will the data will be handled when the `memcached' server is down? * 15.6.5.26: How are auto-increment columns in the MySQL database coordinated across multiple instances of memcached? * 15.6.5.27: Is compression available? * 15.6.5.28: What speed trade offs is there between `memcached' vs MySQL Query Cache? Where you check `memcached', and get data from MySQL and put it in `memcached' or just make a query and results are put into MySQL Query Cache. * 15.6.5.29: Can we implement different types of `memcached' as different nodes in the same server - so can there be deterministic and non deterministic in the same server? * 15.6.5.30: What are best practices for testing an implementation, to ensure that it is an improvement over the MySQL query cache, and to measure the impact of `memcached' configuration changes? And would you recommend keeping the configuration very simple to start? *Questions and Answers* *15.6.5.1: ** Can MySQL actually trigger/store the changed data to memcached? * Yes. You can use the MySQL UDFs for `memcached' and either write statements that directly set the values in the `memcached' server, or use triggers or stored procedures to do it for you. For more information, see *Note ha-memcached-interfaces-mysqludf:: *15.6.5.2: ** Can memcached be run on a Windows environment? * No. Currently `memcached' is available only on the Unix/Linux platform. There is an unofficial port available, see `http://www.codeplex.com/memcachedproviders'. *15.6.5.3: ** Does the `-L' flag automatically sense how much memory is being used by other memcached? * No. There is no communication or sharing of information between `memcached' instances. *15.6.5.4: ** What is the max size of an object you can store in memcache and is that configurable? * The default maximum object size is 1MB. In `memcached' 1.4.2 and later you can change the maximum size of an object using the `-I' command line option. For versions before this, to increase this size, you have to re-compile `memcached'. You can modify the value of the `POWER_BLOCK' within the `slabs.c' file within the source. In `memcached' 1.4.2 and higher you can configure the maximum supported object size by using the `-I' command-line option. For example, to increase the maximum object size to 5MB: $ memcached -I 5m *15.6.5.5: ** Is it true `memcached' will be much more effective with db-read-intensive applications than with db-write-intensive applications? * Yes. `memcached' plays no role in database writes, it is a method of caching data already read from the database in RAM. *15.6.5.6: ** `memcached' is fast - is there any overhead in not using persistent connections? If persistent is always recommended, what are the downsides (for example, locking up)? * If you don't use persistent connections when communicating with `memcached' then there will be a small increase in the latency of opening the connection each time. The effect is comparable to use nonpersistent connections with MySQL. In general, the chance of locking or other issues with persistent connections is minimal, because there is very little locking within `memcached'. If there is a problem then eventually your request will timeout and return no result so your application will need to load from MySQL again. *15.6.5.7: ** How does an event such as a crash of one of the `memcached' servers handled by the `memcached' client? * There is no automatic handling of this. If your client fails to get a response from a server then it should fall back to loading the data from the MySQL database. The client APIs all provide the ability to add and remove `memcached' instances on the fly. If within your application you notice that `memcached' server is no longer responding, your can remove the server from the list of servers, and keys will automatically be redistributed to another `memcached' server in the list. If retaining the cache content on all your servers is important, make sure you use an API that supports a consistent hashing algorithm. For more information, see *Note ha-memcached-using-hashtypes::. *15.6.5.8: ** What's a recommended hardware config for a memcached server? Linux or Windows? * `memcached' is only available on Unix/Linux, so using a Windows machine is not an option. Outside of this, `memcached' has a very low processing overhead. All that is required is spare physical RAM capacity. The point is not that you should necessarily deploy a dedicated `memcached' server. If you have web, application, or database servers that have spare RAM capacity, then use them with `memcached'. If you want to build and deploy a dedicated `memcached' servers, then you use a relatively low-power CPU, lots of RAM and one or more Gigabit Ethernet interfaces. *15.6.5.9: ** Doing a direct telnet to the memcached port, is that just for that one machine, or does it magically apply across all nodes? * Just one. There is no communication between different instances of `memcached', even if each instance is running on the same machine. *15.6.5.10: ** Is memcached more effective for video and audio as opposed to textual read/writes * `memcached' doesn't care what information you are storing. To `memcached', any value you store is just a stream of data. Remember, though, that the maximum size of an object you can store in `memcached' is 1MB, but can be configured to be larger by using the `-I' option in `memcached' 1.4.2 and later, or by modifying the source in versions before 1.4.2. If you plan on using `memcached' with audio and video content you will probably want to increase the maximum object size. Also remember that `memcached' is a solution for caching information for reading. It shouldn't be used for writes, except when updating the information in the cache. *15.6.5.11: ** If you log a complex class (with methods that do calculation etc) will the get from Memcache re-create the class on the way out? * In general, yes. If the serialization method within the API/language that you are using supports it, then methods and other information will be stored and retrieved. *15.6.5.12: ** If I have an object larger then a MB, do I have to manually split it or can I configure `memcached' to handle larger objects? * You would have to manually split it. `memcached' is very simple, you give it a key and some data, it tries to cache it in RAM. If you try to store more than the default maximum size, the value is just truncated for speed reasons. *15.6.5.13: ** Can `memcached' work with `ASPX'? * There are ports and interfaces for many languages and environments. ASPX relies on an underlying language such as C# or VisualBasic, and if you are using ASP.NET then there is a C# `memcached' library. For more information, see . (https://sourceforge.net/projects/memcacheddotnet/) *15.6.5.14: ** Are there any, or are there any plans to introduce, a framework to hide the interaction of memcached from the application; that is, within hibernate? * There are lots of projects working with `memcached'. There is a Google Code implementation of Hibernate and `memcached' working together. See `http://code.google.com/p/hibernate-memcached/'. *15.6.5.15: ** So the responsibility lies with the application to populate and get records from the database as opposed to being a transparent cache layer for the db? * Yes. You load the data from the database and write it into the cache provided by `memcached'. Using `memcached' as a simple database row cache, however, is probably inefficient. The best way to use `memcached' is to load all of the information from the database relating to a particular object, and then cache the entire object. For example, in a blogging environment, you might load the blog, associated comments, categories and so on, and then cache all of the information relating to that blog post. The reading of the data from the database will require multiple SQL statements and probably multiple rows of data to complete, which is time consuming. Loading the entire blog post and the associated information from `memcached' is just one operation and doesn't involve using the disk or parsing the SQL statement. *15.6.5.16: ** How does `memcached' compare to nCache? * The main benefit of `memcached' is that is very easy to deploy and works with a wide range of languages and environments, including .NET, Java, Perl, Python, PHP, even MySQL. `memcached' is also very lightweight in terms of systems and requirements, and you can easily add as many or as few `memcached' servers as you need without changing the individual configuration. `memcached' does require additional modifications to the application to take advantage of functionality such as multiple `memcached' servers. *15.6.5.17: ** We are caching XML by serialising using saveXML(), because PHP cannot serialize DOM objects; Some of the XML is variable and is modified per-request. Do you recommend caching then using XPath, or is it better to rebuild the DOM from separate node-groups? * You would need to test your application using the different methods to determine this information. You may find that the default serialization within PHP may allow you to store DOM objects directly into the cache. *15.6.5.18: ** How easy is it to introduce `memcached' to an existing enterprise application instead of inclusion at project design? * In general, it is very easy. In many languages and environments the changes to the application will be just a few lines, first to attempt to read from the cache when loading data and then fall back to the old method, and to update the cache with information once the data has been read. `memcached' is designed to be deployed very easily, and you shouldn't require significant architectural changes to your application to use `memcached'. *15.6.5.19: ** Do the memcache UDFs work under 5.1? * Yes. *15.6.5.20: ** Is the data inside of `memcached' secure? * No, there is no security required to access or update the information within a `memcached' instance, which means that anybody with access to the machine has the ability to read, view and potentially update the information. If you want to keep the data secure, you can encrypt and decrypt the information before storing it. If you want to restrict the users capable of connecting to the server, your only choice is to either disable network access, or use IPTables or similar to restrict access to the `memcached' ports to a select set of hosts. *15.6.5.21: ** Is `memcached' typically a better solution for improving speed than MySQL Cluster and\or MySQL Proxy? * Both MySQL Cluster and MySQL Proxy still require access to the underlying database to retrieve the information. This implies both a parsing overhead for the statement and, often, disk based access to retrieve the data you have selected. The advantage of `memcached' is that you can store entire objects or groups of information that may require multiple SQL statements to obtain. Restoring the result of 20 SQL statements formatted into a structure that your application can use directly without requiring any additional processing is always going to be faster than building that structure by loading the rows from a database. *15.6.5.22: ** File socket support for `memcached' from the localhost use to the local memcached server? * You can use the `-s' option to `memcached' to specify the location of a file socket. This automatically disables network support. *15.6.5.23: ** How expensive is it to establish a memcache connection? Should those connections be pooled? * Opening the connection is relatively inexpensive, because there is no security, authentication or other handshake taking place before you can start sending requests and getting results. Most APIs support a persistent connection to a `memcached' instance to reduce the latency. Connection pooling would depend on the API you are using, but if you are communicating directly over TCP/IP, then connection pooling would provide some small performance benefit. *15.6.5.24: ** What are the advantages of using UDFs when the get/sets are manageable from within the client code rather than the db? * Sometimes you want to be able to be able to update the information within `memcached' based on a generic database activity, rather than relying on your client code. For example, you may want to update status or counter information in `memcached' through the use of a trigger or stored procedure. For some situations and applications the existing use of a stored procedure for some operations means that updating the value in `memcached' from the database is easier than separately loading and communicating that data to the client just so the client can talk to `memcached.' In other situations, when you are using a number of different clients and different APIs, you don't want to have to write (and maintain) the code required to update `memcached' in all the environments. Instead, you do this from within the database and the client never gets involved. *15.6.5.25: ** How will the data will be handled when the `memcached' server is down? * The behavior is entirely application dependent. Most applications will fall back to loading the data from the database (just as if they were updating the `memcached') information. If you are using multiple `memcached' servers, you may also want to remove a server from the list to prevent the missing server affecting performance. This is because the client will still attempt to communicate the `memcached' that corresponds to the key you are trying to load. *15.6.5.26: ** How are auto-increment columns in the MySQL database coordinated across multiple instances of memcached? * They aren't. There is no relationship between MySQL and `memcached' unless your application (or, if you are using the MySQL UDFs for `memcached', your database definition) creates one. If you are storing information based on an auto-increment key into multiple instances of `memcached' then the information will only be stored on one of the `memcached' instances anyway. The client uses the key value to determine which `memcached' instance to store the information, it doesn't store the same information across all the instances, as that would be a waste of cache memory. *15.6.5.27: ** Is compression available? * Yes. Most of the client APIs support some sort of compression, and some even allow you to specify the threshold at which a value is deemed appropriate for compression during storage. *15.6.5.28: ** What speed trade offs is there between `memcached' vs MySQL Query Cache? Where you check `memcached', and get data from MySQL and put it in `memcached' or just make a query and results are put into MySQL Query Cache. * In general, the time difference between getting data from the MySQL Query Cache and getting the exact same data from `memcached' is very small. However, the benefit of `memcached' is that you can store any information, including the formatted and processed results of many queries into a single `memcached' key. Even if all the queries that you executed could be retrieved from the Query Cache without having to go to disk, you would still be running multiple queries (with network and other overhead) compared to just one for the `memcached' equivalent. If your application uses objects, or does any kind of processing on the information, with `memcached' you can store the post-processed version, so the data you load is immediately available to be used. With data loaded from the Query Cache, you would still have to do that processing. In addition to these considerations, keep in mind that keeping data in the MySQL Query Cache is difficult as you have no control over the queries that are stored. This means that a slightly unusual query can temporarily clear a frequently used (and normally cached) query, reducing the effectiveness of your Query Cache. With `memcached' you can specify which objects are stored, when they are stored, and when they should be deleted giving you much more control over the information stored in the cache. *15.6.5.29: ** Can we implement different types of `memcached' as different nodes in the same server - so can there be deterministic and non deterministic in the same server? * Yes. You can run multiple instances of `memcached' on a single server, and in your client configuration you choose the list of servers you want to use. *15.6.5.30: ** What are best practices for testing an implementation, to ensure that it is an improvement over the MySQL query cache, and to measure the impact of `memcached' configuration changes? And would you recommend keeping the configuration very simple to start? * The best way to test the performance is to start up a `memcached' instance. First, modify your application so that it stores the data just before the data is about to be used or displayed into `memcached'.Since the APIs handle the serialization of the data, it should just be a one line modification to your code. Then, modify the start of the process that would normally load that information from MySQL with the code that requests the data from `memcached'. If the data cannot be loaded from `memcached', default to the MySQL process. All of the changes required will probably amount to just a few lines of code. To get the best benefit, make sure you cache entire objects (for example, all the components of a web page, blog post, discussion thread, etc.), rather than using `memcached' as a simple cache of individuals rows of MySQL tables. You should see performance benefits almost immediately. Keeping the configuration very simple at the start, or even over the long term, is very easy with `memcached'. Once you have the basic structure up and running, the only change you may want to make is to add more servers into the list of servers used by your clients. You don't need to manage the `memcached' servers, and there is no complex configuration, just add more servers to the list and let the client API and the `memcached' servers make the decisions.  File: manual.info, Node: mysql-proxy, Prev: ha-memcached, Up: ha-overview 15.7 MySQL Proxy ================ * Menu: * mysql-proxy-platforms:: MySQL Proxy Supported Platforms * mysql-proxy-install:: Installing MySQL Proxy * mysql-proxy-configuration:: MySQL Proxy Command Options * mysql-proxy-scripting:: MySQL Proxy Scripting * mysql-proxy-using:: Using MySQL Proxy * mysql-proxy-faq:: MySQL Proxy FAQ The MySQL Proxy is an application that communicates over the network using the MySQL network protocol and provides communication between one or more MySQL servers and one or more MySQL clients. In the most basic configuration, MySQL Proxy simply interposes itself between the server and clients, passing queries from the clients to the MySQL Server and returning the responses from the MySQL Server to the appropriate client. Because MySQL Proxy uses the MySQL network protocol, it can be used without modification with any MySQL-compatible client that uses the protocol. This includes the *Note `mysql': mysql. command-line client, any clients that uses the MySQL client libraries, and any connector that supports the MySQL network protocol. In addition to the basic pass-through configuration, the MySQL Proxy is also capable of monitoring and altering the communication between the client and the server. Query interception enables you to add profiling, and interception of the exchanges is scriptable using the Lua scripting language. By intercepting the queries from the client, the proxy can insert additional queries into the list of queries sent to the server, and remove the additional results when they are returned by the server. Using this functionality you can return the results from the original query to the client while adding informational statements to each query, for example, to monitor their execution time or progress, and separately log the results. The proxy enables you to perform additional monitoring, filtering, or manipulation of queries without requiring you to make any modifications to the client and without the client even being aware that it is communicating with anything but a genuine MySQL server. This documentation covers MySQL Proxy 0.8.0. *Warning*: MySQL Proxy is currently an Alpha release and should not be used within production environments. *Important*: MySQL Proxy is compatible with MySQL 5.0 or later. Testing has not been performed with Version 4.1. Please provide feedback on your experiences using the MySQL Proxy Forum (http://forums.mysql.com/list.php?146).  File: manual.info, Node: mysql-proxy-platforms, Next: mysql-proxy-install, Prev: mysql-proxy, Up: mysql-proxy 15.7.1 MySQL Proxy Supported Platforms -------------------------------------- MySQL Proxy is currently available as a precompiled binary for the following platforms: * Linux (including Red Hat, Fedora, Debian, SuSE) and derivatives * Mac OS X * FreeBSD * IBM AIX * Sun Solaris * Microsoft Windows (including Microsoft Windows XP, Microsoft Windows Vista, Microsoft Windows Server 2003, Microsoft Windows Server 2008) *Note*: You must have the .NET Framework 1.1 or higher installed. Other Unix/Linux platforms not listed should be compatible by using the source package and building MySQL Proxy locally. System requirements for the MySQL Proxy application are the same as the main MySQL server. Currently MySQL Proxy is compatible only with MySQL 5.0.1 and later. MySQL Proxy is provided as a standalone, statically linked binary. You need not have MySQL or Lua installed.  File: manual.info, Node: mysql-proxy-install, Next: mysql-proxy-configuration, Prev: mysql-proxy-platforms, Up: mysql-proxy 15.7.2 Installing MySQL Proxy ----------------------------- * Menu: * mysql-proxy-install-binary:: Installing MySQL Proxy from a Binary Distribution * mysql-proxy-install-source:: Installing MySQL Proxy from a Source Distribution * mysql-proxy-install-cvs:: Installing MySQL Proxy from the Bazaar Repository * mysql-proxy-configuration-windows:: Setting Up MySQL Proxy as a Windows Service You have three choices for installing MySQL Proxy: * Precompiled binaries are available for a number of different platforms. See *Note mysql-proxy-install-binary::. * You can install from the source code if you want to build on an environment not supported by the binary distributions. See *Note mysql-proxy-install-source::. * The latest version of the MySQL Proxy source code is available through a development repository is the best way to stay up to date with the latest fixes and revisions. See *Note mysql-proxy-install-cvs::.  File: manual.info, Node: mysql-proxy-install-binary, Next: mysql-proxy-install-source, Prev: mysql-proxy-install, Up: mysql-proxy-install 15.7.2.1 Installing MySQL Proxy from a Binary Distribution .......................................................... If you download a binary package, you must extract and copy the package contents to your desired installation directory. The package contains files required by MySQL Proxy, including additional Lua scripts and other components required for execution. To install, unpack the archive into the desired directory, then modify your `PATH' environment variable so that you can use the *Note `mysql-proxy': mysql-proxy. command directly: shell> cd /usr/local shell> tar zxf mysql-proxy-0.7.2-OSX10.5.tar.gz shell> PATH=$PATH:/usr/local/MYSQL-PROXY-0.7.2-OSX10.5-X86/sbin If you want to update the path globally on a system, you may need administrator privileges to modify the appropriate `/etc/profile', `/etc/bashrc', or other system configuration file. On Windows, you can update the `PATH' environment variable using this procedure: 1. On the Windows desktop, right-click the `My Computer' icon, and select `Properties'. 2. Next select the `Advanced' tab from the `System Properties' menu that appears, and click the `Environment Variables' button. 3. Under `System Variables', select `Path', then click the `Edit' button. The `Edit System Variable' dialogue should appear.  File: manual.info, Node: mysql-proxy-install-source, Next: mysql-proxy-install-cvs, Prev: mysql-proxy-install-binary, Up: mysql-proxy-install 15.7.2.2 Installing MySQL Proxy from a Source Distribution .......................................................... If you download a source package, you must compile the MySQL Proxy before using it. A build from source requires that the following prerequisite components be installed: * `libevent' 1.x or higher (1.3b or later is preferred) * `lua' 5.1.x or higher * `glib2' 2.6.0 or higher * `pkg-config' * `libtool' 1.5 or higher * MySQL 5.0.x or higher developer files *Note*: On some operating systems you may need to manually build the required components to get the latest version. If you have trouble compiling MySQL Proxy, consider using a binary distributions instead. After you have verified that the prerequisite components are installed, configure and build MySQL Proxy: shell> tar zxf mysql-proxy-0.7.2.tar.gz shell> cd mysql-proxy-0.7.2 shell> ./configure shell> make If you want to test the build, use the `check' target to `make': shell> make check The tests try to connect to `localhost' using the `root' user. If you need to provide a password, set the `MYSQL_PASSWORD' environment variable: shell> MYSQL_PASSWORD=root_pwd make check You can install using the `install' target: shell> make install By default, *Note `mysql-proxy': mysql-proxy. is installed into `/usr/local/sbin/mysql-proxy'. The Lua example scripts are installed into `/usr/local/share'.  File: manual.info, Node: mysql-proxy-install-cvs, Next: mysql-proxy-configuration-windows, Prev: mysql-proxy-install-source, Up: mysql-proxy-install 15.7.2.3 Installing MySQL Proxy from the Bazaar Repository .......................................................... The MySQL Proxy source is available through a public Bazaar repository and is the quickest way to get the latest releases and fixes. A build from the Bazaar repository requires that the following prerequisite components be installed: * Bazaar 1.10.0 or later * `libtool' 1.5 or higher * `autoconf' 2.56 or higher * `automake' 1.10 or higher * `libevent' 1.x or higher (1.3b or later is preferred) * `lua' 5.1.x or higher * `glib2' 2.4.0 or higher * `pkg-config' * MySQL 5.0.x or higher developer files The *Note `mysql-proxy': mysql-proxy. source is hosted on Launchpad. To check out a local copy of the Bazaar repository, use `bzr': shell> bzr branch lp:mysql-proxy The preceding command downloads a complete version of the Bazaar repository for *Note `mysql-proxy': mysql-proxy. The main source files are located within the `trunk' subdirectory. The configuration scripts must be generated before you can configure and build *Note `mysql-proxy': mysql-proxy. The `autogen.sh' script generates the required configuration scripts for you: shell> sh ./autogen.sh The `autogen.sh' script creates the standard `configure' script, which you then use to configure and build with `make': shell> ./configure shell> make shell> make install If you want to create a standalone source distribution, identical to the source distribution available for download, use this command: shell> make distcheck The preceding command creates the file `mysql-proxy-0.7.2.tar.gz' (with the corresponding current version) within the current directory.  File: manual.info, Node: mysql-proxy-configuration-windows, Prev: mysql-proxy-install-cvs, Up: mysql-proxy-install 15.7.2.4 Setting Up MySQL Proxy as a Windows Service .................................................... The MySQL distribution on Windows includes the `mysql-proxy-svc.exe' command that enables a MySQL Proxy instance to be managed by the Windows service control manager. This enables you to control the service without separately running the MySQL Proxy application, and allows for automatically starting and stopping the MySQL Proxy service during boot, reboot and shutdown. To set up a MySQL Proxy service, you must use the `sc' command to create a new service using the MySQL Proxy service command. Specify the MySQL Proxy options on the `sc' command line, and identify the service with a unique name. For example, to configure a new MySQL Proxy instance that will automatically start when your system boots, redirecting queries to the local MySQL server: C:\> sc create "Proxy" DisplayName= "MySQL Proxy" start= "auto" » binPath= "C:\Program Files\MySQL\mysql-proxy-0.8.0\bin\mysql-proxy-svc.exe » --proxy-backend-addresses=127.0.0.1:3306" *Note*: The space following the equal sign after each property is required; failure to include it results in an error. The preceding command creates a new service called `Proxy'. You can start and stop the service using the `net start|stop' command with the service name. The service is not automatically started after it has been created. To start the service: C:\> net start proxy The MySQL Proxy service is starting. The MySQL Proxy service was started successfully. You can specify any additional command-line options you need to the `sc' command. You can also set up multiple MySQL Proxy services on the same machine (providing they are configured to listen on different ports and/or IP addresses. You can delete a service that you have created: C:\> sc delete proxy For more information on creating services using `sc', see How to create a Windows service by using Sc.exe (http://support.microsoft.com/kb/251192).  File: manual.info, Node: mysql-proxy-configuration, Next: mysql-proxy-scripting, Prev: mysql-proxy-install, Up: mysql-proxy 15.7.3 MySQL Proxy Command Options ---------------------------------- To start MySQL Proxy, you can run it directly from the command line: shell> mysql-proxy However, for most situations you will want to specify at the very least the host name or address and the port number of the backend MySQL server to which the MySQL Proxy should pass queries. You can specify options to *Note `mysql-proxy': mysql-proxy. either on the command line, or by using a configuration file and the `--defaults-file' command-line option to specify the file location. If you use a configuration file, it should be formatted as follows: * Options must be specified within a `[mysql-proxy]' configuration group. For example: [mysql-proxy] admin-address = HOST:PORT * All configuration options should be specified in the form of a configuration name and the value you want to set. * For options that are a simple toggle on the command line (for example, `--proxy-skip-profiling'), you must use `true' or `false'. For example, the following is invalid: [mysql-proxy] proxy-skip-profiling But this is valid: [mysql-proxy] proxy-skip-profiling = true * The configuration file should have permissions of `0660' (readable and writable by user and group, no access for others). Failure to adhere to any of these requirements causes *Note `mysql-proxy': mysql-proxy. to generate an error during startup. The following tables list the supported configuration file and command-line options. *`mysql-proxy' Help Options* Format Option File Description IntroductionDeprecatedRemoved -help help Show help options -help-admin help-admin Show admin module options -help-all help-all Show all help options -help-proxy help-proxy Show proxy module options *`mysql-proxy' Admin Options* Format Option File Description IntroductionDeprecatedRemoved -admin-address=host:portadmin-address=host:portThe admin module listening host and port -admin-lua-script=file_nameadmin-lua-script=file_nameScript to execute by the admin module -admin-password=passwordadmin-password=passwordAuthentication password for admin module -admin-username=user_nameadmin-username=user_nameAuthentication user name for admin module -proxy-address=host:portproxy-address=host:portThe listening proxy server host and port *`mysql-proxy' Proxy Options* Format Option File Description IntroductionDeprecatedRemoved -no-proxy no-proxy Do not start the proxy module -proxy-backend-addresses=host:portproxy-backend-addresses=host:portThe MySQL server host and port -proxy-fix-bug-25371proxy-fix-bug-25371Enable the fix for Bug 0.8.1 #25371 for older libmysql versions -proxy-lua-script=file_nameproxy-lua-script=file_nameFilename for Lua script for proxy operations -proxy-pool-no-change-userproxy-pool-no-change-userDo not use the protocol CHANGE_USER command to reset the connection when coming from the connection pool -proxy-read-only-backend-addresses=host:portproxy-read-only-backend-addresses=host:portThe MySQL server host and port (read only) -proxy-skip-profilingproxy-skip-profilingDisable query profiling *`mysql-proxy' Applications Options* Format Option File Description IntroductionDeprecatedRemoved -basedir=dir_namebasedir=dir_nameThe base directory prefix for paths in the configuration -daemon daemon Start in daemon mode -defaults-file=file_name The configuration file to use -event-threads=countevent-threads=countThe number of event-handling threads -keepalive keepalive Try to restart the proxy if a crash occurs -log-backtrace-on-crashlog-backtrace-on-crashTry to invoke the debugger and generate a backtrace on crash -log-file=file_namelog-file=file_nameThe file where error messages are logged -log-level=levellog-level=levelThe logging level -log-use-sysloglog-use-syslogLog errors to syslog -lua-cpath=dir_namelua-cpath=dir_nameSet the LUA_CPATH -lua-path=dir_namelua-path=dir_nameSet the LUA_PATH -max-open-files=countmax-open-files=countThe maximum number of open files to support -pid-file=file_namepid-file=file_nameFile in which to store the process ID -plugin-dir=dir_nameplugin-dir=dir_nameDirectory containing plugin files -plugins=plugin,...plugins=plugin,...List of plugins to load -user=user_nameuser=user_nameThe user to use when running mysql-proxy -version version Show version information Except as noted in the following details, all of the options can be used within the configuration file by supplying the option and the corresponding value. For example: [mysql-proxy] log-file = /var/log/mysql-proxy.log log-level = message * `--help', `-h' Options for help *Command-Line `--help' Format* ** `-h' *Option-File Format* `help' Show available help options. * `--help-admin' Options for help-admin *Command-Line `--help-admin' Format* *Option-File Format* `help-admin' Show options for the admin module. * `--help-all' Options for help-all *Command-Line `--help-all' Format* *Option-File Format* `help-all' Show all help options. * `--help-proxy' Options for help-proxy *Command-Line `--help-proxy' Format* *Option-File Format* `help-proxy' Show options for the proxy module. * `--admin-address=HOST:PORT' Options for admin-address *Command-Line `--admin-address=host:port' Format* *Option-File Format* `admin-address=host:port' *Permitted Values * *Type* `string' *Default* `:4041' The host name (or IP address) and port for the administration port. The default is `localhost:4041'. * `--admin-lua-script=FILE_NAME' Options for admin-lua-script *Command-Line `--admin-lua-script=file_name' Format* *Option-File Format* `admin-lua-script=file_name' *Permitted Values * *Type* `file name' *Default* `' The script to use for the proxy administration module. * `--admin-password=PASSWORD' Options for admin-password *Command-Line `--admin-password=password' Format* *Option-File Format* `admin-password=password' *Permitted Values * *Type* `string' *Default* `' The password to use to authenticate users wanting to connect to the MySQL Proxy administration module. This module uses the MySQL protocol to request a user name and password for connections. * `--admin-username=USER_NAME' Options for admin-username *Command-Line `--admin-username=user_name' Format* *Option-File Format* `admin-username=user_name' *Permitted Values * *Type* `string' *Default* `root' The user name to use to authenticate users wanting to connect to the MySQL Proxy administration module. This module uses the MySQL protocol to request a user name and password for connections. The default user name is `root'. * `--basedir=DIR_NAME' Options for basedir *Command-Line `--basedir=dir_name' Format* *Option-File Format* `basedir=dir_name' *Permitted Values * *Type* `directory name' The base directory to use as a prefix for all other file name configuration options. The base name should be an absolute (not relative) directory. If you specify a relative directory, *Note `mysql-proxy': mysql-proxy. generates an error during startup. * `--daemon' Options for daemon *Command-Line `--daemon' Format* *Option-File Format* `daemon' Starts the proxy in daemon mode. * `--defaults-file=FILE_NAME' Options for defaults-file *Command-Line `--defaults-file=file_name' Format* The file to read for configuration options. If not specified, MySQL Proxy takes options only from the command line. * `--event-threads=COUNT' Options for event-threads *Command-Line `--event-threads=count' Format* *Option-File Format* `event-threads=count' *Permitted Values * *Type* `numeric' *Default* `1' The number of event threads to reserve to handle incoming requests. * `--keepalive' Options for keepalive *Command-Line `--keepalive' Format* *Option-File Format* `keepalive' Create a process surrounding the main *Note `mysql-proxy': mysql-proxy. process that attempts to restart the main *Note `mysql-proxy': mysql-proxy. process in the event of a crash or other failure. *Note*: The `--keepalive' option is not available on Microsoft Windows. When running as a service, *Note `mysql-proxy': mysql-proxy. automatically restarts. * `--log-backtrace-on-crash' Options for log-backtrace-on-crash *Command-Line `--log-backtrace-on-crash' Format* *Option-File Format* `log-backtrace-on-crash' Log a backtrace to the error log and try to initialize the debugger in the event of a failure. * `--log-file=FILE_NAME' Options for log-file *Command-Line `--log-file=file_name' Format* *Option-File Format* `log-file=file_name' *Permitted Values * *Type* `file name' The file to use to record log information. If this option is not given, *Note `mysql-proxy': mysql-proxy. logs to the standard error output. * `--log-level=LEVEL' Options for log-level *Command-Line `--log-level=level' Format* *Option-File Format* `log-level=level' *Permitted Values * *Type* `enumeration' *Valid Values* `error' `warning' `info' `message' `debug' The log level to use when outputting error messages. Messages with that level (or lower) are output. For example, `message' level also outputs message with `info', `warning', and `error' levels. * `--log-use-syslog' Options for log-use-syslog *Command-Line `--log-use-syslog' Format* *Option-File Format* `log-use-syslog' Log errors to the syslog (Unix/Linux only). * `--lua-cpath=DIR_NAME' Options for lua-cpath *Command-Line `--lua-cpath=dir_name' Format* *Option-File Format* `lua-cpath=dir_name' *Permitted Values * *Type* `directory name' The `LUA_CPATH' to use when loading compiled modules or libraries for Lua scripts. * `--lua-path=DIR_NAME' Options for lua-path *Command-Line `--lua-path=dir_name' Format* *Option-File Format* `lua-path=dir_name' *Permitted Values * *Type* `directory name' The `LUA_CPATH' to use when loading modules for Lua. * `--max-open-files=COUNT' Options for max-open-files *Command-Line `--max-open-files=count' Format* *Option-File Format* `max-open-files=count' *Permitted Values * *Type* `numeric' The maximum number of open files and sockets supported by the *Note `mysql-proxy': mysql-proxy. process. You may need to increase this with certain scripts. * `--no-proxy' Options for no-proxy *Command-Line `--no-proxy' Format* *Option-File Format* `no-proxy' Disable the proxy module. * `--plugin-dir=DIR_NAME' Options for plugin-dir *Command-Line `--plugin-dir=dir_name' Format* *Option-File Format* `plugin-dir=dir_name' *Permitted Values * *Type* `directory name' The directory to use when loading plugins for *Note `mysql-proxy': mysql-proxy. * `--plugins=PLUGIN,...' Options for plugins *Command-Line `--plugins=plugin,...' Format* *Option-File Format* `plugins=plugin,...' *Permitted Values * *Type* `string' A comma-separated list of plugins to load. * `--proxy-address=HOST:PORT', `-P HOST:PORT' Options for proxy-address *Command-Line `--proxy-address=host:port' Format* ** `-P host:port' *Option-File Format* `proxy-address=host:port' *Permitted Values * *Type* `string' *Default* `:4040' The listening host name (or IP address) and port of the proxy server. The default is `:4040' (all IPs on port 4040). * `--proxy-read-only-backend-addresses=HOST:PORT', `-r HOST:PORT' Options for proxy-read-only-backend-addresses *Command-Line `--proxy-read-only-backend-addresses=host:port' Format* ** `-r host:port' *Option-File Format* `proxy-read-only-backend-addresses=host:port' *Permitted Values * *Type* `string' The listening host name (or IP address) and port of the proxy server for read-only connections. The default is for this information not to be set. *Note*: Setting this value only configures the servers within the corresponding internal structure (see `proxy.global.backends'). You can determine the backend type by checking the `type' field for each connection. You should therefore only use this option in combination with a script designed to make use of the different backend types. When using this option on the command line, you can specify the option and the server multiple times to specify multiple backends. For example: shell> mysql-proxy --proxy-read-only-backend-addresses 192.168.0.1:3306 --proxy-read-only-backend-addresses 192.168.0.2:3306 When using the option within the configuration file, you should separate multiple servers by commas. The equivalent of the preceding example would be: ... proxy-read-only-backend-addresses = 192.168.0.1:3306,192.168.0.2:3306 * `--proxy-backend-addresses=HOST:PORT', `-b HOST:PORT' Options for proxy-backend-addresses *Command-Line `--proxy-backend-addresses=host:port' Format* ** `-b host:port' *Option-File Format* `proxy-backend-addresses=host:port' *Permitted Values * *Type* `string' *Default* `127.0.0.1:3306' The host name (or IP address) and port of the MySQL server to connect to. You can specify multiple backend servers by supplying multiple options. Clients are connected to each backend server in round-robin fashion. For example, if you specify two servers A and B, the first client connection will go to server A; the second client connection to server B and the third client connection to server A. When using this option on the command line, you can specify the option and the server multiple times to specify multiple backends. For example: shell> mysql-proxy --proxy-backend-addresses 192.168.0.1:3306 --proxy-backend-addresses 192.168.0.2:3306 When using the option within the configuration file, you should separate multiple servers by commas. The equivalent of the preceding example would be: ... proxy-backend-addresses = 192.168.0.1:3306,192.168.0.2:3306 * `--proxy-pool-no-change-user' Options for proxy-pool-no-change-user *Command-Line `--proxy-pool-no-change-user' Format* *Option-File Format* `proxy-pool-no-change-user' Disable use of the MySQL protocol `CHANGE_USER' command when reusing a connection from the pool of connections specified by the `proxy-backend-addresses' list. * `--proxy-skip-profiling' Options for proxy-skip-profiling *Command-Line `--proxy-skip-profiling' Format* *Option-File Format* `proxy-skip-profiling' Disable query profiling (statistics time tracking). The default is for tracking to be enabled. * `--proxy-fix-bug-25371' Options for proxy-fix-bug-25371 *Version Removed* 0.8.1 *Command-Line `--proxy-fix-bug-25371' Format* *Option-File Format* `proxy-fix-bug-25371' Enable a workaround for an issue when connecting to a MySQL server later than 5.1.12 when using a MySQL client library of any earlier version. This option was removed in *Note `mysql-proxy': mysql-proxy. 0.8.1. Now, *Note `mysql-proxy': mysql-proxy. returns an error message at the protocol level if it sees a `COM_CHANGE_USER' being sent to a server that has a version from 5.1.14 to 5.1.17. * `--proxy-lua-script=FILE_NAME', `-s FILE_NAME' Options for proxy-lua-script *Command-Line `--proxy-lua-script=file_name' Format* ** `-s file_name' *Option-File Format* `proxy-lua-script=file_name' *Permitted Values * *Type* `file name' The Lua script file to be loaded. Note that the script file is not physically loaded and parsed until a connection is made. Also note that the specified Lua script is reloaded for each connection; if the content of the Lua script changes while *Note `mysql-proxy': mysql-proxy. is running, the updated content is automatically used when a new connection is made. * `--pid-file=FILE_NAME' Options for pid-file *Command-Line `--pid-file=file_name' Format* *Option-File Format* `pid-file=file_name' *Permitted Values * *Type* `file name' The name of the file in which to store the process ID. * `--user=USER_NAME' Options for user *Command-Line `--user=user_name' Format* *Option-File Format* `user=user_name' *Permitted Values * *Type* `string' Run *Note `mysql-proxy': mysql-proxy. as the specified `user'. * `--version', `-V' Options for version *Command-Line `--version' Format* ** `-V' *Option-File Format* `version' Show the version number. The most common usage is as a simple proxy service (that is, without additional scripting). For basic proxy operation, you must specify at least one `proxy-backend-addresses' option to specify the MySQL server to connect to by default: shell> mysql-proxy --proxy-backend-addresses=MySQL.example.com:3306 The default proxy port is `4040', so you can connect to your MySQL server through the proxy by specifying the host name and port details: shell> mysql --host=localhost --port=4040 If your server requires authentication information, this will be passed through natively without alteration by *Note `mysql-proxy': mysql-proxy, so you must also specify the required authentication information: shell> mysql --host=localhost --port=4040 \ --user=user_name --password=password You can also connect to a read-only port (which filters out *Note `UPDATE': update. and *Note `INSERT': insert. queries) by connecting to the read-only port. By default the host name is the default, and the port is `4042', but you can alter the host/port information by using the `--proxy-read-only-backend-addresses' command-line option. For more detailed information on how to use these command-line options, and *Note `mysql-proxy': mysql-proxy. in general in combination with Lua scripts, see *Note mysql-proxy-using::.  File: manual.info, Node: mysql-proxy-scripting, Next: mysql-proxy-using, Prev: mysql-proxy-configuration, Up: mysql-proxy 15.7.4 MySQL Proxy Scripting ---------------------------- * Menu: * mysql-proxy-scripting-injection:: Proxy Scripting Sequence During Query Injection * mysql-proxy-scripting-structures:: Internal Structures * mysql-proxy-scripting-connect-server:: Capturing a Connection with `connect_server()' * mysql-proxy-scripting-read-handshake:: Examining the Handshake with `read_handshake()' * mysql-proxy-scripting-read-auth:: Examining the Authentication Credentials with `read_auth()' * mysql-proxy-scripting-read-auth-result:: Accessing Authentication Information with `read_auth_result()' * mysql-proxy-scripting-read-query:: Manipulating Queries with `read_query()' * mysql-proxy-scripting-read-query-result:: Manipulating Results with `read_query_result()' You can control how MySQL Proxy manipulates and works with the queries and results that are passed on to the MySQL server through the use of the embedded Lua scripting language. You can find out more about the Lua programming language from the Lua Web site (http://www.lua.org). The following diagram shows an overview of the classes exposed by MySQL Proxy. MySQL Proxy architecture The primary interaction between MySQL Proxy and the server is provided by defining one or more functions through an Lua script. A number of functions are supported, according to different events and operations in the communication sequence between a client and one or more backend MySQL servers: * `connect_server()': This function is called each time a connection is made to MySQL Proxy from a client. You can use this function during load-balancing to intercept the original connection and decide which server the client should ultimately be attached to. If you do not define a special solution, a simple round-robin style distribution is used by default. * `read_handshake()': This function is called when the initial handshake information is returned by the server. You can capture the handshake information returned and provide additional checks before the authorization exchange takes place. * `read_auth()': This function is called when the authorization packet (user name, password, default database) are submitted by the client to the server for authentication. * `read_auth_result()': This function is called when the server returns an authorization packet to the client indicating whether the authorization succeeded. * `read_query()': This function is called each time a query is sent by the client to the server. You can use this to edit and manipulate the original query, including adding new queries before and after the original statement. You can also use this function to return information directly to the client, bypassing the server, which can be useful to filter unwanted queries or queries that exceed known limits. * `read_query_result()': This function is called each time a result is returned from the server, providing you have manually injected queries into the query queue. If you have not explicitly injected queries within the `read_query()' function, this function is not triggered. You can use this to edit the result set, or to remove or filter the result sets generated from additional queries you injected into the queue when using `read_query()'. The following table describes the direction of information flow at the point when the function is triggered. Function Supplied Information Direction `connect_server()' None Client to Server `read_handshake()' None Server to Client `read_auth()' None Client to Server `read_auth_result()' None Server to Client `read_query()' Query Client to Server `read_query_result()' Query result Server to Client By default, all functions return a result that indicates whether the data should be passed on to the client or server (depending on the direction of the information being transferred). This return value can be overridden by explicitly returning a constant indicating that a particular response should be sent. For example, it is possible to construct result set information by hand within `read_query()' and to return the result set directly to the client without ever sending the original query to the server. In addition to these functions, a number of built-in structures provide control over how MySQL Proxy forwards queries and returns the results by providing a simplified interface to elements such as the list of queries and the groups of result sets that are returned.  File: manual.info, Node: mysql-proxy-scripting-injection, Next: mysql-proxy-scripting-structures, Prev: mysql-proxy-scripting, Up: mysql-proxy-scripting 15.7.4.1 Proxy Scripting Sequence During Query Injection ........................................................ The following figure gives an example of how the proxy might be used when injecting queries into the query queue. Because the proxy sits between the client and MySQL server, what the proxy sends to the server, and the information that the proxy ultimately returns to the client, need not match or correlate. Once the client has connected to the proxy, the sequence shown in the following diagram occurs for each individual query sent by the client. MySQL Proxy architecture 1. When the client submits one query to the proxy, the `read_query()' function within the proxy is triggered. The function adds the query to the query queue. 2. Once manipulation by `read_query()' has completed, the queries are submitted, sequentially, to the MySQL server. 3. The MySQL server returns the results from each query, one result set for each query submitted. The `read_query_result()' function is triggered for each result set, and each invocation can decide which result set to return to the client For example, you can queue additional queries into the global query queue to be processed by the server. This can be used to add statistical information by adding queries before and after the original query, changing the original query: SELECT * FROM City; Into a sequence of queries: SELECT NOW(); SELECT * FROM City; SELECT NOW(); You can also modify the original statement; for example, to add *Note `EXPLAIN': explain. to each statement executed to get information on how the statement was processed, again altering our original SQL statement into a number of statements: SELECT * FROM City; EXPLAIN SELECT * FROM City; In both of these examples, the client would have received more result sets than expected. Regardless of how you manipulate the incoming query and the returned result, the number of queries returned by the proxy must match the number of original queries sent by the client. You could adjust the client to handle the multiple result sets sent by the proxy, but in most cases you will want the existence of the proxy to remain transparent. To ensure that the number of queries and result sets match, you can use the MySQL Proxy `read_query_result()' to extract the additional result set information and return only the result set the client originally requested back to the client. You can achieve this by giving each query that you add to the query queue a unique ID, then filter out queries that do not match the original query ID when processing them with `read_query_result()'.  File: manual.info, Node: mysql-proxy-scripting-structures, Next: mysql-proxy-scripting-connect-server, Prev: mysql-proxy-scripting-injection, Up: mysql-proxy-scripting 15.7.4.2 Internal Structures ............................ There are a number of internal structures within the scripting element of MySQL Proxy. The primary structure is `proxy' and this provides an interface to the many common structures used throughout the script, such as connection lists and configured backend servers. Other structures, such as the incoming packet from the client and result sets are only available within the context of one of the scriptable functions. Attribute Description `connection' A structure containing the active client connections. For a list of attributes, see `proxy.connection'. `servers' A structure containing the list of configured backend servers. For a list of attributes, see `proxy.global.backends'. `queries' A structure containing the queue of queries that will be sent to the server during a single client query. For a list of attributes, see `proxy.queries'. `PROXY_VERSION' The version number of MySQL Proxy, encoded in hex. You can use this to check that the version number supports a particular option from within the Lua script. Note that the value is encoded as a hex value, so to check the version is at least 0.5.1 you compare against `0x00501'. *`proxy.connection'* The `proxy.connection' object is read only, and provides information about the current connection, and is split into a `client' and `server' tables. This enables you to examine information about both the incoming client connections to the proxy (`client'), and to the backend servers (`server'). Attribute Description `client.default_db' Default database requested by the client `client.username' User name used to authenticate `client.scrambled_password'The scrambled version of the password used to authenticate `client.dst.name' The combined `address:port' of the Proxy port used by this client (should match the `--proxy-address' configuration parameter) `client.dst.address' The IP address of the of the Proxy port used by this client `client.dst.port' The port number of the of the Proxy port used by this client `client.src.name' The combined `address:port' of the client (originating) TCP/IP endpoint `client.src.address' The IP address of the client (originating) TCP/IP port `client.src.port' The port of the client (originating) TCP/IP endpoint `server.scramble_buffer'The scramble buffer used to scramble the password `server.mysqld_version'The MySQL version number of the server `server.thread_id' The ID of the thread handling the connection to the current server `server.dst.name' The combined `address:port' for the backend server for the current connection (i.e. the connection to the MySQL server) `server.dst.address' The address for the backend server `server.dst.port' The port for the backend server `server.src.name' The combined `address:port' for the TCP/IP endpoint used by the Proxy to connect to the backend server `server.src.address' The address of the endpoint for the proxy-side connection to the MySQL server `server.src.port' The port of the endpoint for the proxy-side connection to the MySQL server *`proxy.global.backends'* The `proxy.global.backends' table is partially writable and contains an array of all the configured backend servers and the server metadata (IP address, status, etc.). You can determine the array index of the current connection using `proxy.connection["backend_ndx"]' which is the index into this table of the backend server being used by the active connection. The attributes for each entry within the `proxy.global.backends' table are shown in this table. Attribute Description `dst.name' The combined `address:port' of the backend server. `dst.address' The IP address of the backend server. `dst.port' The port of the backend server. `connected_clients' The number of clients currently connected. `state' The status of the backend server. See *Note mysql-proxy-scripting-structures-backend-states::. `type' The type of the backend server. You can use this to identify whether the backed was configured as a standard read/write backend, or a read-only backend. You can compare this value to the `proxy.BACKEND_TYPE_RW' and `proxy.BACKEND_TYPE_RO'. *`proxy.queries'* The `proxy.queries' object is a queue representing the list of queries to be sent to the server. The queue is not populated automatically, but if you do not explicitly populate the queue, queries are passed on to the backend server verbatim. Also, if you do not populate the query queue by hand, the `read_query_result()' function is not triggered. The following methods are supported for populating the `proxy.queries' object. Function Description `append(id,packet,[options])'Appends a query to the end of the query queue. The `id' is an integer identifier that you can use to recognize the query results when they are returned by the server. The packet should be a properly formatted query packet. The optional `options' should be a table containing the options specific to this packet. `prepend(id,packet)' Prepends a query to the query queue. The `id' is an identifier that you can use to recognize the query results when they are returned by the server. The packet should be a properly formatted query packet. `reset()' Empties the query queue. `len()' Returns the number of query packets in the queue. For example, you could append a query packet to the `proxy.queries' queue by using the `append()': proxy.queries:append(1,packet) The optional third argument to `append()' should contain the options for the packet. If you want to have access to the result set through the `read_query_result()' function, you must set the `resultset_is_needed' flag to `true': proxy.queries:append( 1, packet, { resultset_is_needed = true } ) If that flag is `false' (the default), proxy will: * Send the result set to the client as soon as it is received * Reduce memory usage (because the result set is not stored internally for processing) * Reduce latency of returning results to the client * Pass data from server to client unaltered The default mode is therefore quicker and useful if you only want to monitor the queries sent, and the basic statistics. If, however, you want to perform any kind of manipulation on the returned data, you must set the flag to `true', which will: * Store the result set so that it can be processed * Enable modification of the result set before it is returned to the client * Enable you to discard the result set instead of returning it to the client *`proxy.response'* The `proxy.response' structure is used when you want to return your own MySQL response, instead of forwarding a packet that you have received a backend server. The structure holds the response type information, an optional error message, and the result set (rows/columns) that you want to return. Attribute Description `type' The type of the response. The type must be either `MYSQLD_PACKET_OK' or `MYSQLD_PACKET_ERR'. If the `MYSQLD_PACKET_ERR', you should set the value of the `mysql.response.errmsg' with a suitable error message. `errmsg' A string containing the error message that will be returned to the client. `resultset' A structure containing the result set information (columns and rows), identical to what would be returned when returning a results from a *Note `SELECT': select. query. When using `proxy.response' you either set `proxy.response.type' to `proxy.MYSQLD_PACKET_OK' and then build `resultset' to contain the results that you want to return, or set `proxy.response.type' to `proxy.MYSQLD_PACKET_ERR' and set the `proxy.response.errmsg' to a string with the error message. To send the completed result set or error message, you should return the `proxy.PROXY_SEND_RESULT' to trigger the return of the packet information. An example of this can be seen in the `tutorial-resultset.lua' script within the MySQL Proxy package: if string.lower(command) == "show" and string.lower(option) == "querycounter" then --- -- proxy.PROXY_SEND_RESULT requires -- -- proxy.response.type to be either -- * proxy.MYSQLD_PACKET_OK or -- * proxy.MYSQLD_PACKET_ERR -- -- for proxy.MYSQLD_PACKET_OK you need a resultset -- * fields -- * rows -- -- for proxy.MYSQLD_PACKET_ERR -- * errmsg proxy.response.type = proxy.MYSQLD_PACKET_OK proxy.response.resultset = { fields = { { type = proxy.MYSQL_TYPE_LONG, name = "global_query_counter", }, { type = proxy.MYSQL_TYPE_LONG, name = "query_counter", }, }, rows = { { proxy.global.query_counter, query_counter } } } -- we have our result, send it back return proxy.PROXY_SEND_RESULT elseif string.lower(command) == "show" and string.lower(option) == "myerror" then proxy.response.type = proxy.MYSQLD_PACKET_ERR proxy.response.errmsg = "my first error" return proxy.PROXY_SEND_RESULT *`proxy.response.resultset'* The `proxy.response.resultset' structure should be populated with the rows and columns of data that you want to return. The structure contains the information about the entire result set, with the individual elements of the data shown in the following table. Attribute Description `fields' The definition of the columns being returned. This should be a dictionary structure with the `type' specifying the MySQL data type, and the `name' specifying the column name. Columns should be listed in the order of the column data that will be returned. `flags' A number of flags related to the result set. Valid flags include `auto_commit' (whether an automatic commit was triggered), `no_good_index_used' (the query executed without using an appropriate index), and `no_index_used' (the query executed without using any index). `rows' The actual row data. The information should be returned as an array of arrays. Each inner array should contain the column data, with the outer array making up the entire result set. `warning_count' The number of warnings for this result set. `affected_rows' The number of rows affected by the original statement. `insert_id' The last insert ID for an auto-incremented column in a table. `query_status' The status of the query operation. You can use the `MYSQLD_PACKET_OK' or `MYSQLD_PACKET_ERR' constants to populate this parameter. For an example showing how to use this structure, see `proxy.response'. *Proxy Return State Constants* The following constants are used internally by the proxy to specify the response to send to the client or server. All constants are exposed as values within the main `proxy' table. Constant Description `PROXY_SEND_QUERY' Causes the proxy to send the current contents of the queries queue to the server. `PROXY_SEND_RESULT' Causes the proxy to send a result set back to the client. `PROXY_IGNORE_RESULT' Causes the proxy to drop the result set (nothing is returned to the client). As constants, these entities are available without qualification in the Lua scripts. For example, at the end of the `read_query_result()' you might return `PROXY_IGNORE_RESULT:' return proxy.PROXY_IGNORE_RESULT *Packet State Constants* The following states describe the status of a network packet. These items are entries within the main `proxy' table. Constant Description `MYSQLD_PACKET_OK' The packet is OK `MYSQLD_PACKET_ERR' The packet contains error information `MYSQLD_PACKET_RAW' The packet contains raw data *Backend State/Type Constants* The following constants are used either to define the status or type of the backend MySQL server to which the proxy is connected. These items are entries within the main `proxy' table. Constant Description `BACKEND_STATE_UNKNOWN'The current status is unknown `BACKEND_STATE_UP' The backend is known to be up (available) `BACKEND_STATE_DOWN' The backend is known to be down (unavailable) `BACKEND_TYPE_UNKNOWN' Backend type is unknown `BACKEND_TYPE_RW' Backend is available for read/write `BACKEND_TYPE_RO' Backend is available only for read-only use *Server Command Constants* The following values are used in the packets exchanged between the client and server to identify the information in the rest of the packet. These items are entries within the main `proxy' table. The packet type is defined as the first character in the sent packet. For example, when intercepting packets from the client to edit or monitor a query, you would check that the first byte of the packet was of type `proxy.COM_QUERY'. Constant Description `COM_SLEEP' Sleep `COM_QUIT' Quit `COM_INIT_DB' Initialize database `COM_QUERY' Query `COM_FIELD_LIST' Field List `COM_CREATE_DB' Create database `COM_DROP_DB' Drop database `COM_REFRESH' Refresh `COM_SHUTDOWN' Shutdown `COM_STATISTICS' Statistics `COM_PROCESS_INFO' Process List `COM_CONNECT' Connect `COM_PROCESS_KILL' Kill `COM_DEBUG' Debug `COM_PING' Ping `COM_TIME' Time `COM_DELAYED_INSERT' Delayed insert `COM_CHANGE_USER' Change user `COM_BINLOG_DUMP' Binlog dump `COM_TABLE_DUMP' Table dump `COM_CONNECT_OUT' Connect out `COM_REGISTER_SLAVE' Register slave `COM_STMT_PREPARE' Prepare server-side statement `COM_STMT_EXECUTE' Execute server-side statement `COM_STMT_SEND_LONG_DATA'Long data `COM_STMT_CLOSE' Close server-side statement `COM_STMT_RESET' Reset statement `COM_SET_OPTION' Set option `COM_STMT_FETCH' Fetch statement `COM_DAEMON' Daemon (MySQL 5.1 only) `COM_ERROR' Error *MySQL Type Constants* These constants are used to identify the field types in the query result data returned to clients from the result of a query. These items are entries within the main `proxy' table. Constant Field Type `MYSQL_TYPE_DECIMAL' Decimal `MYSQL_TYPE_NEWDECIMAL'Decimal (MySQL 5.0 or later) `MYSQL_TYPE_TINY' Tiny `MYSQL_TYPE_SHORT' Short `MYSQL_TYPE_LONG' Long `MYSQL_TYPE_FLOAT' Float `MYSQL_TYPE_DOUBLE' Double `MYSQL_TYPE_NULL' Null `MYSQL_TYPE_TIMESTAMP' Timestamp `MYSQL_TYPE_LONGLONG' Long long `MYSQL_TYPE_INT24' Integer `MYSQL_TYPE_DATE' Date `MYSQL_TYPE_TIME' Time `MYSQL_TYPE_DATETIME' Datetime `MYSQL_TYPE_YEAR' Year `MYSQL_TYPE_NEWDATE' Date (MySQL 5.0 or later) `MYSQL_TYPE_ENUM' Enumeration `MYSQL_TYPE_SET' Set `MYSQL_TYPE_TINY_BLOB' Tiny Blob `MYSQL_TYPE_MEDIUM_BLOB'Medium Blob `MYSQL_TYPE_LONG_BLOB' Long Blob `MYSQL_TYPE_BLOB' Blob `MYSQL_TYPE_VAR_STRING'Varstring `MYSQL_TYPE_STRING' String `MYSQL_TYPE_TINY' Tiny (compatible with `MYSQL_TYPE_CHAR)' `MYSQL_TYPE_ENUM' Enumeration (compatible with `MYSQL_TYPE_INTERVAL') `MYSQL_TYPE_GEOMETRY' Geometry `MYSQL_TYPE_BIT' Bit  File: manual.info, Node: mysql-proxy-scripting-connect-server, Next: mysql-proxy-scripting-read-handshake, Prev: mysql-proxy-scripting-structures, Up: mysql-proxy-scripting 15.7.4.3 Capturing a Connection with `connect_server()' ....................................................... When the proxy accepts a connection from a MySQL client, the `connect_server()' function is called. There are no arguments to the function, but you can use and if necessary manipulate the information in the `proxy.connection' table, which is unique to each client session. For example, if you have multiple backend servers, you can specify which server that connection should use by setting the value of `proxy.connection.backend_ndx' to a valid server number. The following code chooses between two servers based on whether the current time in minutes is odd or even: function connect_server() print("--> a client really wants to talk to a server") if (tonumber(os.date("%M")) % 2 == 0) then proxy.connection.backend_ndx = 2 print("Choosing backend 2") else proxy.connection.backend_ndx = 1 print("Choosing backend 1") end print("Using " .. proxy.global.backends[proxy.connection.backend_ndx].dst.name) end This example also displays the IP address/port combination by accessing the information from the internal `proxy.global.backends' table.  File: manual.info, Node: mysql-proxy-scripting-read-handshake, Next: mysql-proxy-scripting-read-auth, Prev: mysql-proxy-scripting-connect-server, Up: mysql-proxy-scripting 15.7.4.4 Examining the Handshake with `read_handshake()' ........................................................ Handshake information is sent by the server to the client after the initial connection (through `connect_server()') has been made. The handshake information contains details about the MySQL version, the ID of the thread that will handle the connection information, and the IP address of the client and server. This information is exposed through the `proxy.connection' structure. * `proxy.connection.server.mysqld_version': The version of the MySQL server. * `proxy.connection.server.thread_id': The thread ID. * `proxy.connection.server.scramble_buffer': The password scramble buffer. * `proxy.connection.server.dst.name': The IP address of the server. * `proxy.connection.client.src.name': The IP address of the client. For example, you can print out the handshake data and refuse clients by IP address with the following function: function read_handshake() print("<-- let's send him some information about us") print(" mysqld-version: " .. proxy.connection.server.mysqld_version) print(" thread-id : " .. proxy.connection.server.thread_id) print(" scramble-buf : " .. string.format("%q",proxy.connection.server.scramble_buffer)) print(" server-addr : " .. proxy.connection.server.dst.name) print(" client-addr : " .. proxy.connection.client.dst.name) if not proxy.connection.client.src.name:match("^127.0.0.1:") then proxy.response.type = proxy.MYSQLD_PACKET_ERR proxy.response.errmsg = "only local connects are allowed" print("we don't like this client"); return proxy.PROXY_SEND_RESULT end end Note that you must return an error packet to the client by using `proxy.PROXY_SEND_RESULT'.  File: manual.info, Node: mysql-proxy-scripting-read-auth, Next: mysql-proxy-scripting-read-auth-result, Prev: mysql-proxy-scripting-read-handshake, Up: mysql-proxy-scripting 15.7.4.5 Examining the Authentication Credentials with `read_auth()' .................................................................... The `read_auth()' function is triggered when an authentication handshake is initiated by the client. In the execution sequence, `read_auth()' occurs immediately after `read_handshake()', so the server selection has already been made, but the connection and authorization information has not yet been provided to the backend server. You can obtain the authentication information by examining the `proxy.connection.client' structure. For more information, see `proxy.connection'. For example, you can print the user name and password supplied during authorization using: function read_auth() print(" username : " .. proxy.connection.client.username) print(" password : " .. string.format("%q", proxy.connection.client.scrambled_password)) end You can interrupt the authentication process within this function and return an error packet back to the client by constructing a new packet and returning `proxy.PROXY_SEND_RESULT': proxy.response.type = proxy.MYSQLD_PACKET_ERR proxy.response.errmsg = "Logins are not allowed" return proxy.PROXY_SEND_RESULT  File: manual.info, Node: mysql-proxy-scripting-read-auth-result, Next: mysql-proxy-scripting-read-query, Prev: mysql-proxy-scripting-read-auth, Up: mysql-proxy-scripting 15.7.4.6 Accessing Authentication Information with `read_auth_result()' ....................................................................... The return packet from the server during authentication is captured by `read_auth_result()'. The only argument to this function is the authentication packet returned by the server. As the packet is a raw MySQL network protocol packet, you must access the first byte to identify the packet type and contents. The `MYSQLD_PACKET_ERR' and `MYSQLD_PACKET_OK' constants can be used to identify whether the authentication was successful: function read_auth_result(auth) local state = auth.packet:byte() if state == proxy.MYSQLD_PACKET_OK then print("<-- auth ok"); elseif state == proxy.MYSQLD_PACKET_ERR then print("<-- auth failed"); else print("<-- auth ... don't know: " .. string.format("%q", auth.packet)); end end If a long-password capable client tries to authenticate to a server that supports long passwords, but the user password provided is actually short, `read_auth_result()' will be called twice. The first time, `auth.packet:byte()' will equal 254, indicating that the client should try again using the old password protocol. The second time time `read_auth_result()/' is called, `auth.packet:byte()' will indicate whether the authentication actually succeeded.  File: manual.info, Node: mysql-proxy-scripting-read-query, Next: mysql-proxy-scripting-read-query-result, Prev: mysql-proxy-scripting-read-auth-result, Up: mysql-proxy-scripting 15.7.4.7 Manipulating Queries with `read_query()' ................................................. The `read_query()' function is called once for each query submitted by the client and accepts a single argument, the query packet that was provided. To access the content of the packet, you must parse the packet contents manually. For example, you can intercept a query packet and print out the contents using the following function definition: function read_query( packet ) if packet:byte() == proxy.COM_QUERY then print("we got a normal query: " .. packet:sub(2)) end end This example checks the first byte of the packet to determine the type. If the type is `COM_QUERY' (see *Note mysql-proxy-scripting-structures-command-constants::), we extract the query from the packet and print it. The structure of the packet type supplied is important. In the case of a `COM_QUERY' packet, the remaining contents of the packet are the text of the query string. In this example, no changes have been made to the query or the list of queries that will ultimately be sent to the MySQL server. To modify a query, or add new queries, you must populate the query queue (`proxy.queries'), then execute the queries that you have placed into the queue. If you do not modify the original query or the queue, the query received from the client is sent to the MySQL server verbatim. When adding queries to the queue, you should follow these guidelines: * The packets inserted into the queue must be valid query packets. For each packet, you must set the initial byte to the packet type. If you are appending a query, you can append the query statement to the rest of the packet. * Once you add a query to the queue, the queue is used as the source for queries sent to the server. If you add a query to the queue to add more information, you must also add the original query to the queue or it will not be executed. * Once the queue has been populated, you must set the return value from `read_query()' to indicate whether the query queue should be sent to the server. * When you add queries to the queue, you should add an ID. The ID you specify is returned with the result set so that you identify each query and corresponding result set. The ID has no other purpose than as an identifier for correlating the query and result set. When operating in a passive mode, during profiling for example, you want to identify the original query and the corresponding result set so that the results expect by the client can be returned correctly. * Unless your client is designed to cope with more result sets than queries, you should ensure that the number of queries from the client match the number of results sets returned to the client. Using the unique ID and removing result sets you inserted will help. Normally, the `read_query()' and `read_query_result()' function are used in conjunction with each other to inject additional queries and remove the additional result sets. However, `read_query_result()' is only called if you populate the query queue within `read_query()'.  File: manual.info, Node: mysql-proxy-scripting-read-query-result, Prev: mysql-proxy-scripting-read-query, Up: mysql-proxy-scripting 15.7.4.8 Manipulating Results with `read_query_result()' ........................................................ The `read_query_result()' is called for each result set returned by the server only if you have manually injected queries into the query queue. If you have not manipulated the query queue, this function is not called. The function supports a single argument, the result packet, which provides a number of properties: * `id': The ID of the result set, which corresponds to the ID that was set when the query packet was submitted to the server when using `append(id)' on the query queue. You must have set the `resultset_is_needed' flag to `append' to intercept the result set before it is returned to the client. See *Note mysql-proxy-scripting-structures-queries::. * `query': The text of the original query. * `query_time': The number of microseconds required to receive the first row of a result set since the query was sent to the server. * `response_time': The number of microseconds required to receive the last row of the result set since the query was sent to the server. * `resultset': The content of the result set data. By accessing the result information from the MySQL server, you can extract the results that match the queries that you injected, return different result sets (for example, from a modified query), and even create your own result sets. The following Lua script, for example, will output the query, followed by the query time and response time (that is, the time to execute the query and the time to return the data for the query) for each query sent to the server: function read_query( packet ) if packet:byte() == proxy.COM_QUERY then print("we got a normal query: " .. packet:sub(2)) proxy.queries:append(1, packet ) return proxy.PROXY_SEND_QUERY end end function read_query_result(inj) print("query-time: " .. (inj.query_time / 1000) .. "ms") print("response-time: " .. (inj.response_time / 1000) .. "ms") end You can access the rows of returned results from the result set by accessing the `rows' property of the `resultset' property of the result that is exposed through `read_query_result()'. For example, you can iterate over the results showing the first column from each row using this Lua fragment: for row in inj.resultset.rows do print("injected query returned: " .. row[1]) end Just like `read_query()', `read_query_result()' can return different values for each result according to the result returned. If you have injected additional queries into the query queue, for example, you will want to remove the results returned from those additional queries and return only the results from the query originally submitted by the client. The following example injects additional `SELECT NOW()' statements into the query queue, giving them a different ID to the ID of the original query. Within `read_query_result()', if the ID for the injected queries is identified, we display the result row, and return the `proxy.PROXY_IGNORE_RESULT' from the function so that the result is not returned to the client. If the result is from any other query, we print out the query time information for the query and return the default, which passes on the result set unchanged. We could also have explicitly returned `proxy.PROXY_IGNORE_RESULT' to the MySQL client. function read_query( packet ) if packet:byte() == proxy.COM_QUERY then proxy.queries:append(2, string.char(proxy.COM_QUERY) .. "SELECT NOW()", {resultset_is_needed = true} ) proxy.queries:append(1, packet, {resultset_is_needed = true}) proxy.queries:append(2, string.char(proxy.COM_QUERY) .. "SELECT NOW()", {resultset_is_needed = true} ) return proxy.PROXY_SEND_QUERY end end function read_query_result(inj) if inj.id == 2 then for row in inj.resultset.rows do print("injected query returned: " .. row[1]) end return proxy.PROXY_IGNORE_RESULT else print("query-time: " .. (inj.query_time / 1000) .. "ms") print("response-time: " .. (inj.response_time / 1000) .. "ms") end end For further examples, see *Note mysql-proxy-using::.  File: manual.info, Node: mysql-proxy-using, Next: mysql-proxy-faq, Prev: mysql-proxy-scripting, Up: mysql-proxy 15.7.5 Using MySQL Proxy ------------------------ * Menu: * mysql-proxy-using-admin:: Using the Administration Interface There are a number of different ways to use MySQL Proxy. At the most basic level, you can allow MySQL Proxy to pass queries from clients to a single server. To use MySQL Proxy in this mode, you just have to specify on the command line the backend server to which the proxy should connect: shell> mysql-proxy --proxy-backend-addresses=sakila:3306 If you specify multiple backend MySQL servers, the proxy connects each client to each server in a round-robin fashion. Suppose that you have two MySQL servers, A and B. The first client to connect is connected to server A, the second to server B, the third to server A. For example: shell> mysql-proxy \ --proxy-backend-addresses=narcissus:3306 \ --proxy-backend-addresses=nostromo:3306 When you specify multiple servers in this way, the proxy automatically identifies when a MySQL server has become unavailable and marks it accordingly. New connections are automatically attached to a server that is available, and a warning is reported to the standard output from *Note `mysql-proxy': mysql-proxy.: network-mysqld.c.367: connect(nostromo:3306) failed: Connection refused network-mysqld-proxy.c.2405: connecting to backend (nostromo:3306) failed, marking it as down for ... Lua scripts enable a finer level of control, both over the connections and their distribution and how queries and result sets are processed. When using an Lua script, you must specify the name of the script on the command line using the `--proxy-lua-script' option: shell> mysql-proxy --proxy-lua-script=mc.lua --proxy-backend-addresses=sakila:3306 When you specify a script, the script is not executed until a connection is made. This means that faults with the script are not raised until the script is executed. Script faults will not affect the distribution of queries to backend MySQL servers. *Note*: Because a script is not read until the connection is made, you can modify the contents of the Lua script file while the proxy is still running and the modified script is automatically used for the next connection. This ensures that MySQL Proxy remains available because it need not be restarted for the changes to take effect.  File: manual.info, Node: mysql-proxy-using-admin, Prev: mysql-proxy-using, Up: mysql-proxy-using 15.7.5.1 Using the Administration Interface ........................................... The *Note `mysql-proxy': mysql-proxy. administration interface can be accessed using any MySQL client using the standard protocols. You can use the administration interface to gain information about the proxy server as a whole - standard connections to the proxy are isolated to operate as if you were connected directly to the backend MySQL server. In *Note `mysql-proxy': mysql-proxy. 0.8.0 and earlier, a rudimentary interface was built into the proxy. In later versions this was replaced so that you must specify an administration script to be used when users connect to the administration interface. To use the administration interface, you should specify the user name and password required to connect to the admin service (using the `--admin-username' and `--admin-password' options). You must also specify the Lua script to be used as the interface to the administration service by using the `admin-lua-script' script option to point to a Lua script. For example, you can create a basic interface to the internal components of the *Note `mysql-proxy': mysql-proxy. system using the following script, written by Diego Medina: --[[ Copyright 2008, 2010, Oracle and/or its affiliates. All rights reserved. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; version 2 of the License. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA --]] -- admin.lua --[[ See http://forge.mysql.com/tools/tool.php?id=78 (Thanks to Jan Kneschke) See http://www.chriscalender.com/?p=41 (Thanks to Chris Calender) See http://datacharmer.blogspot.com/2009/01/mysql-proxy-is-back.html (Thanks Giuseppe Maxia) --]] function set_error(errmsg) proxy.response = { type = proxy.MYSQLD_PACKET_ERR, errmsg = errmsg or "error" } end function read_query(packet) if packet:byte() ~= proxy.COM_QUERY then set_error("[admin] we only handle text-based queries (COM_QUERY)") return proxy.PROXY_SEND_RESULT end local query = packet:sub(2) local rows = { } local fields = { } -- try to match the string up to the first non-alphanum local f_s, f_e, command = string.find(packet, "^%s*(%w+)", 2) local option if f_e then -- if that match, take the next sub-string as option f_s, f_e, option = string.find(packet, "^%s+(%w+)", f_e + 1) end -- we got our commands, execute it if command == "show" and option == "querycounter" then --- -- proxy.PROXY_SEND_RESULT requires -- -- proxy.response.type to be either -- * proxy.MYSQLD_PACKET_OK or -- * proxy.MYSQLD_PACKET_ERR -- -- for proxy.MYSQLD_PACKET_OK you need a resultset -- * fields -- * rows -- -- for proxy.MYSQLD_PACKET_ERR -- * errmsg proxy.response.type = proxy.MYSQLD_PACKET_OK proxy.response.resultset = { fields = { { type = proxy.MYSQL_TYPE_LONG, name = "query_counter", }, }, rows = { { proxy.global.query_counter } } } -- we have our result, send it back return proxy.PROXY_SEND_RESULT elseif command == "show" and option == "myerror" then proxy.response.type = proxy.MYSQLD_PACKET_ERR proxy.response.errmsg = "my first error" return proxy.PROXY_SEND_RESULT elseif string.sub(packet, 2):lower() == 'select help' then return show_process_help() elseif string.sub(packet, 2):lower() == 'show proxy processlist' then return show_process_table() elseif query == "SELECT * FROM backends" then fields = { { name = "backend_ndx", type = proxy.MYSQL_TYPE_LONG }, { name = "address", type = proxy.MYSQL_TYPE_STRING }, { name = "state", type = proxy.MYSQL_TYPE_STRING }, { name = "type", type = proxy.MYSQL_TYPE_STRING }, } for i = 1, #proxy.global.backends do local b = proxy.global.backends[i] rows[#rows + 1] = { i, b.dst.name, b.state, b.type } end else set_error() return proxy.PROXY_SEND_RESULT end proxy.response = { type = proxy.MYSQLD_PACKET_OK, resultset = { fields = fields, rows = rows } } return proxy.PROXY_SEND_RESULT end function make_dataset (header, dataset) proxy.response.type = proxy.MYSQLD_PACKET_OK proxy.response.resultset = { fields = {}, rows = {} } for i,v in pairs (header) do table.insert(proxy.response.resultset.fields, {type = proxy.MYSQL_TYPE_STRING, name = v}) end for i,v in pairs (dataset) do table.insert(proxy.response.resultset.rows, v ) end return proxy.PROXY_SEND_RESULT end function show_process_table() local dataset = {} local header = { 'Id', 'IP Address', 'Time' } local rows = {} for t_i, t_v in pairs (proxy.global.process) do for s_i, s_v in pairs ( t_v ) do table.insert(rows, { t_i, s_v.ip, os.date('%c',s_v.ts) }) end end return make_dataset(header,rows) end function show_process_help() local dataset = {} local header = { 'command', 'description' } local rows = { {'SELECT HELP', 'This command.'}, {'SHOW PROXY PROCESSLIST', 'Show all connections and their true IP Address.'}, } return make_dataset(header,rows) end function dump_process_table() proxy.global.initialize_process_table() print('current contents of process table') for t_i, t_v in pairs (proxy.global.process) do print ('session id: ', t_i) for s_i, s_v in pairs ( t_v ) do print ( '\t', s_i, s_v.ip, s_v.ts ) end end print ('---END PROCESS TABLE---') end --[[ Help we use a simple string-match to split commands are word-boundaries mysql> show querycounter is split into command = "show" option = "querycounter" spaces are ignored, the case has to be as is. mysql> show myerror returns a error-packet --]] The script works in combination with a main proxy script, `reporter.lua': --[[ Copyright 2008, 2010, Oracle and/or its affiliates. All rights reserved. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; version 2 of the License. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA --]] -- reporter.lua --[[ See http://forge.mysql.com/tools/tool.php?id=78 (Thanks to Jan Kneschke) See http://www.chriscalender.com/?p=41 (Thanks to Chris Calender) See http://datacharmer.blogspot.com/2009/01/mysql-proxy-is-back.html (Thanks Giuseppe Maxia) --]] proxy.global.query_counter = proxy.global.query_counter or 0 function proxy.global.initialize_process_table() if proxy.global.process == nil then proxy.global.process = {} end if proxy.global.process[proxy.connection.server.thread_id] == nil then proxy.global.process[proxy.connection.server.thread_id] = {} end end function read_auth_result( auth ) local state = auth.packet:byte() if state == proxy.MYSQLD_PACKET_OK then proxy.global.initialize_process_table() table.insert( proxy.global.process[proxy.connection.server.thread_id], { ip = proxy.connection.client.src.name, ts = os.time() } ) end end function disconnect_client() local connection_id = proxy.connection.server.thread_id if connection_id then -- client has disconnected, set this to nil proxy.global.process[connection_id] = nil end end --- -- read_query() can return a resultset -- -- You can use read_query() to return a result-set. -- -- @param packet the mysql-packet sent by the client -- -- @return -- * nothing to pass on the packet as is, -- * proxy.PROXY_SEND_QUERY to send the queries from the proxy.queries queue -- * proxy.PROXY_SEND_RESULT to send your own result-set -- function read_query( packet ) -- a new query came in in this connection -- using proxy.global.* to make it available to the admin plugin proxy.global.query_counter = proxy.global.query_counter + 1 end To use the script, save the first script to a file (`admin.lua' in the following example) and the other to `reporter.lua', then run *Note `mysql-proxy': mysql-proxy. specifying the admin script and a backend MySQL server: shell> mysql-proxy --admin-lua-script=admin.lua --admin-password=password \ » --admin-username=root --proxy-backend-addresses=127.0.0.1:3306 -proxy-lua-script=reporter.lua In a different window, connect to the MySQL server through the proxy: shell> mysql --user=root --password=password --port=4040 Welcome to the MySQL monitor. Commands end with ; or \g. Your MySQL connection id is 1798669 Server version: 5.0.70-log Gentoo Linux mysql-5.0.70-r1 Type 'help;' or '\h' for help. Type '\c' to clear the buffer. mysql> In another different window, connect to the *Note `mysql-proxy': mysql-proxy. admin service using the specified user name and password: shell> mysql --user=root --password=password --port=4041 --host=localhost Welcome to the MySQL monitor. Commands end with ; or \g. Your MySQL connection id is 1 Server version: 5.0.99-agent-admin Type 'help;' or '\h' for help. Type '\c' to clear the buffer. mysql> To monitor the status of the proxy, ask for a list of the current active processes: mysql> show proxy processlist; +---------+---------------------+--------------------------+ | Id | IP Address | Time | +---------+---------------------+--------------------------+ | 1798669 | 192.168.0.112:52592 | Wed Jan 20 16:58:00 2010 | +---------+---------------------+--------------------------+ 1 row in set (0.00 sec) mysql> For more information on the example, see MySQL Proxy Admin Example (http://fmpwizard.blogspot.com/2009/04/how-do-i-use-mysql-proxy-admin-plugin.html).  File: manual.info, Node: mysql-proxy-faq, Prev: mysql-proxy-using, Up: mysql-proxy 15.7.6 MySQL Proxy FAQ ---------------------- *Questions* * 15.7.6.1: In load balancing, how can I separate reads from writes? * 15.7.6.2: How do I use a socket with MySQL Proxy? Proxy change logs mention that support for UNIX sockets has been added. * 15.7.6.3: Can I use MySQL Proxy with all versions of MySQL? * 15.7.6.4: Can I run MySQL Proxy as a daemon? * 15.7.6.5: Will the proxy road map involve moving popular features from Lua to C? (For example, Read/Write splitting.) * 15.7.6.6: Do proxy applications run on a separate server? If not, what is the overhead incurred by Proxy on the DB server side? * 15.7.6.7: With load balancing, what happens to transactions? Are all queries sent to the same server? * 15.7.6.8: We have looked at using MySQL Proxy but we are concerned about the alpha status. When do you think the proxy will be considered production ready? * 15.7.6.9: Is it possible to use MySQL Proxy with updating a Lucene index (or Solr) by making TCP calls to that server to update? * 15.7.6.10: Is the system context switch expensive, how much overhead does the Lua script add? * 15.7.6.11: How much latency does a proxy add to a connection? * 15.7.6.12: Do you have to make one large script and call it at proxy startup, can I change scripts without stopping and restarting (interrupting) the proxy? * 15.7.6.13: If MySQL Proxy has to live on same machine as MySQL, are there any tuning considerations to ensure both perform optimally? * 15.7.6.14: Can MySQL Proxy be used on slaves and intercept binary log messages? * 15.7.6.15: I currently use SQL Relay for efficient connection pooling with a number of Apache processes connecting to a MySQL server. Can MySQL Proxy currently accomplish this? My goal is to minimize connection latency while keeping temporary tables available. * 15.7.6.16: Are these reserved function names (for example, `error_result()') that get automatically called? * 15.7.6.17: As the script is re-read by MySQL Proxy, does it cache this or is it looking at the file system with each request? * 15.7.6.18: Given that there is a `connect_server()' function, can a Lua script link up with multiple servers? * 15.7.6.19: Is the MySQL Proxy an API? * 15.7.6.20: The global namespace variable example with quotas does not persist after a reboot, is that correct? * 15.7.6.21: Can MySQL Proxy handle SSL connections? * 15.7.6.22: Could MySQL Proxy be used to capture passwords? * 15.7.6.23: Are there tools for isolating problems? How can someone figure out whether a problem is in the client, the database, or the proxy? * 15.7.6.24: Can you explain the status of your work with `memcached' and MySQL Proxy? * 15.7.6.25: Is MySQL Proxy similar to what is provided by Java connection pools? * 15.7.6.26: So authentication with connection pooling has to be done at every connection? What is the authentication latency? * 15.7.6.27: If you have multiple databases on the same box, can you use proxy to connect to databases on default port 3306? * 15.7.6.28: What about caching the authorization information so clients connecting are given back-end connections that were established with identical authorization information, thus saving a few more round trips? * 15.7.6.29: Is there any big web site using MySQL Proxy? For what purpose and what transaction rate have they achieved? * 15.7.6.30: How does MySQL Proxy compare to DBSlayer? * 15.7.6.31: I tried using MySQL Proxy without any Lua script to try a round-robin type load balancing. In this case, if the first database in the list is down, MySQL Proxy would not connect the client to the second database in the list. * 15.7.6.32: Is it `safe' to use `LuaSocket' with proxy scripts? * 15.7.6.33: How different is MySQL Proxy from DBCP (Database connection pooling) for Apache in terms of connection pooling? * 15.7.6.34: MySQL Proxy can handle about 5000 connections, what is the limit on a MySQL server? * 15.7.6.35: Would the Java-only connection pooling solution work for multiple web servers? With this, I would assume that you can pool across many web servers at once? * 15.7.6.36: Can you dynamically reconfigure the pool of MySQL servers that MySQL Proxy will use for load balancing? * 15.7.6.37: In the quick poll, I see "Load Balancer: read-write splitting" as an option, so would it be correct to say that there are no scripts written for Proxy yet to do this? *Questions and Answers* *15.7.6.1: ** In load balancing, how can I separate reads from writes? * There is no automatic separation of queries that perform reads or writes to the different backend servers. However, you can specify to *Note `mysql-proxy': mysql-proxy. that one or more of the `backend' MySQL servers are read only. shell> mysql-proxy \ --proxy-backend-addresses=10.0.1.2:3306 \ --proxy-read-only-backend-addresses=10.0.1.3:3306 & *15.7.6.2: ** How do I use a socket with MySQL Proxy? Proxy change logs mention that support for UNIX sockets has been added. * Specify the path to the socket: --proxy-backend-addresses=/PATH/TO/SOCKET *15.7.6.3: ** Can I use MySQL Proxy with all versions of MySQL? * MySQL Proxy is designed to work with MySQL 5.0 or higher, and supports the MySQL network protocol for 5.0 and higher. *15.7.6.4: ** Can I run MySQL Proxy as a daemon? * Use the `--daemon' option. To keep track of the process ID, the daemon can be started with the `--pid-file=file' option to save the PID to a known file name. On version 0.5.x, the Proxy cannot be started natively as a daemon. *15.7.6.5: ** Will the proxy road map involve moving popular features from Lua to C? (For example, Read/Write splitting.) * We will keep the high-level parts in the Lua layer to be able to adjust to special situations without a rebuild. Read/Write splitting sometimes needs external knowledge that may only be available by the DBA. *15.7.6.6: ** Do proxy applications run on a separate server? If not, what is the overhead incurred by Proxy on the DB server side? * You can run the proxy on the application server, on its own box, or on the DB-server depending on the use case. *15.7.6.7: ** With load balancing, what happens to transactions? Are all queries sent to the same server? * Without any special customization the whole connection is sent to the same server. That keeps the whole connection state intact. *15.7.6.8: ** We have looked at using MySQL Proxy but we are concerned about the alpha status. When do you think the proxy will be considered production ready? * We are on the road to the next feature release: 0.9.0. It will improve the performance quite a bit. After that we may be able to enter the beta phase. *15.7.6.9: ** Is it possible to use MySQL Proxy with updating a Lucene index (or Solr) by making TCP calls to that server to update? * Yes, but it is not advised for now. *15.7.6.10: ** Is the system context switch expensive, how much overhead does the Lua script add? * Lua is fast and the overhead should be small enough for most applications. The raw packet overhead is around 400 microseconds. *15.7.6.11: ** How much latency does a proxy add to a connection? * In the range of 400 microseconds per request. *15.7.6.12: ** Do you have to make one large script and call it at proxy startup, can I change scripts without stopping and restarting (interrupting) the proxy? * You can just change the script and the proxy will reload it when a client connects. *15.7.6.13: ** If MySQL Proxy has to live on same machine as MySQL, are there any tuning considerations to ensure both perform optimally? * MySQL Proxy can live on any box: application, database, or its own box. MySQL Proxy uses comparatively little CPU or RAM, with negligible additional requirements or overhead. *15.7.6.14: ** Can MySQL Proxy be used on slaves and intercept binary log messages? * We are working on that. See `http://jan.kneschke.de/2008/5/30/mysql-proxy-rbr-to-sbr-decoding' for an example. *15.7.6.15: ** I currently use SQL Relay for efficient connection pooling with a number of Apache processes connecting to a MySQL server. Can MySQL Proxy currently accomplish this? My goal is to minimize connection latency while keeping temporary tables available. * Yes. *15.7.6.16: ** Are these reserved function names (for example, `error_result()') that get automatically called? * Only functions and values starting with `proxy.*' are provided by the proxy. All others are user provided. *15.7.6.17: ** As the script is re-read by MySQL Proxy, does it cache this or is it looking at the file system with each request? * It looks for the script at client-connect and reads it if it has changed, otherwise it uses the cached version. *15.7.6.18: ** Given that there is a `connect_server()' function, can a Lua script link up with multiple servers? * MySQL Proxy provides some tutorials in the source package; one is `examples/tutorial-keepalive.lua'. *15.7.6.19: ** Is the MySQL Proxy an API? * No, MySQL Proxy is an application that forwards packets from a client to a server using the MySQL network protocol. The MySQL Proxy provides a API allowing you to change its behavior. *15.7.6.20: ** The global namespace variable example with quotas does not persist after a reboot, is that correct? * Yes. If you restart the proxy, you lose the results, unless you save them in a file. *15.7.6.21: ** Can MySQL Proxy handle SSL connections? * No, being the man-in-the-middle, Proxy cannot handle encrypted sessions because it cannot share the SSL information. *15.7.6.22: ** Could MySQL Proxy be used to capture passwords? * The MySQL network protocol does not allow passwords to be sent in cleartext, all you could capture is the encrypted version. *15.7.6.23: ** Are there tools for isolating problems? How can someone figure out whether a problem is in the client, the database, or the proxy? * You can set a debug script in the proxy, which is an exceptionally good tool for this purpose. You can see very clearly which component is causing the problem, if you set the right breakpoints. *15.7.6.24: ** Can you explain the status of your work with `memcached' and MySQL Proxy? * There are some ideas to integrate proxy and `memcache' a bit, but no code yet. *15.7.6.25: ** Is MySQL Proxy similar to what is provided by Java connection pools? * Yes and no. Java connection pools are specific to Java applications, MySQL Proxy works with any client API that talks the MySQL network protocol. Also, connection pools do not provide any functionality for intelligently examining the network packets and modifying the contents. *15.7.6.26: ** So authentication with connection pooling has to be done at every connection? What is the authentication latency? * You can skip the round-trip and use the connection as it was added to the pool. As long as the application cleans up the temporary tables it used. The overhead is (as always) around 400 microseconds. *15.7.6.27: ** If you have multiple databases on the same box, can you use proxy to connect to databases on default port 3306? * Yes, MySQL Proxy can listen on any port, provided that none of the MySQL servers are listening on the same port. *15.7.6.28: ** What about caching the authorization information so clients connecting are given back-end connections that were established with identical authorization information, thus saving a few more round trips? * There is an `--proxy-pool-no-change-user' option that provides this functionality. *15.7.6.29: ** Is there any big web site using MySQL Proxy? For what purpose and what transaction rate have they achieved? * Yes, gaiaonline (http://gaiaonline.com/). They have tested MySQL Proxy and seen it handle 2400 queries per second through the proxy. *15.7.6.30: ** How does MySQL Proxy compare to DBSlayer? * DBSlayer is a REST->MySQL tool, MySQL Proxy is transparent to your application. No change to the application is needed. *15.7.6.31: ** I tried using MySQL Proxy without any Lua script to try a round-robin type load balancing. In this case, if the first database in the list is down, MySQL Proxy would not connect the client to the second database in the list. * This issue is fixed in version 0.7.0. *15.7.6.32: ** Is it `safe' to use `LuaSocket' with proxy scripts? * You can, but it is not advised because it may block. *15.7.6.33: ** How different is MySQL Proxy from DBCP (Database connection pooling) for Apache in terms of connection pooling? * Connection Pooling is just one use case of the MySQL Proxy. You can use it for a lot more and it works in cases where you cannot use DBCP (for example, if you do not have Java). *15.7.6.34: ** MySQL Proxy can handle about 5000 connections, what is the limit on a MySQL server? * The server limit is given by the value of the `max_connections' system variable. The default value is version dependent. *15.7.6.35: ** Would the Java-only connection pooling solution work for multiple web servers? With this, I would assume that you can pool across many web servers at once? * Yes. But you can also start one proxy on each application server to get a similar behavior as you have it already. *15.7.6.36: ** Can you dynamically reconfigure the pool of MySQL servers that MySQL Proxy will use for load balancing? * Not yet, it is on the list. We are working on a administration interface for that purpose. *15.7.6.37: ** In the quick poll, I see "Load Balancer: read-write splitting" as an option, so would it be correct to say that there are no scripts written for Proxy yet to do this? * There is a proof of concept script for that included. But its far from perfect and may not work for you yet.  File: manual.info, Node: replication, Next: mysql-cluster, Prev: ha-overview, Up: Top 16 Replication ************** * Menu: * replication-configuration:: Replication Configuration * replication-implementation:: Replication Implementation * replication-solutions:: Replication Solutions * replication-notes:: Replication Notes and Tips Replication enables data from one MySQL database server (the master) to be replicated to one or more MySQL database servers (the slaves). Replication is asynchronous - slaves need not be connected permanently to receive updates from the master. This means that updates can occur over long-distance connections and even over temporary or intermittent connections such as a dial-up service. Depending on the configuration, you can replicate all databases, selected databases, or even selected tables within a database. The target uses for replication in MySQL include: * Scale-out solutions - spreading the load among multiple slaves to improve performance. In this environment, all writes and updates must take place on the master server. Reads, however, may take place on one or more slaves. This model can improve the performance of writes (since the master is dedicated to updates), while dramatically increasing read speed across an increasing number of slaves. * Data security - because data is replicated to the slave, and the slave can pause the replication process, it is possible to run backup services on the slave without corrupting the corresponding master data. * Analytics - live data can be created on the master, while the analysis of the information can take place on the slave without affecting the performance of the master. * Long-distance data distribution - if a branch office would like to work with a copy of your main data, you can use replication to create a local copy of the data for their use without requiring permanent access to the master. Replication in MySQL features support for one-way, asynchronous replication, in which one server acts as the master, while one or more other servers act as slaves. This is in contrast to the _synchronous_ replication which is a characteristic of MySQL Cluster (see *Note mysql-cluster::). There are a number of solutions available for setting up replication between two servers, but the best method to use depends on the presence of data and the engine types you are using. For more information on the available options, see *Note replication-howto::. There are two core types of replication format, Statement Based Replication (SBR), which replicates entire SQL statements, and Row Based Replication (RBR), which replicates only the changed rows. You may also use a third variety, Mixed Based Replication (MBR). For more information on the different replication formats, see *Note replication-formats::. From MySQL 5.1.12 to MySQL 5.1.28, mixed format is the default. Beginning with MySQL 5.1.29, statement-based format is the default. Replication is controlled through a number of different options and variables. These control the core operation of the replication, timeouts, and the databases and filters that can be applied on databases and tables. For more information on the available options, see *Note replication-options::. You can use replication to solve a number of different problems, including problems with performance, supporting the backup of different databases, and as part of a larger solution to alleviate system failures. For information on how to address these issues, see *Note replication-solutions::. For notes and tips on how different data types and statements are treated during replication, including details of replication features, version compatibility, upgrades, and problems and their resolution, including an FAQ, see *Note replication-notes::. For detailed information on the implementation of replication, how replication works, the process and contents of the binary log, background threads and the rules used to decide how statements are recorded and replication, see *Note replication-implementation::.  File: manual.info, Node: replication-configuration, Next: replication-implementation, Prev: replication, Up: replication 16.1 Replication Configuration ============================== * Menu: * replication-howto:: How to Set Up Replication * replication-formats:: Replication Formats * replication-options:: Replication and Binary Logging Options and Variables * replication-administration:: Common Replication Administration Tasks Replication between servers in MySQL is based on the binary logging mechanism. The MySQL instance operating as the master (the source of the database changes) writes updates and changes as `events' to the binary log. The information in the binary log is stored in different logging formats according to the database changes being recorded. Slaves are configured to read the binary log from the master and to execute the events in the binary log on the slave's local database. The master is `dumb' in this scenario. Once binary logging has been enabled, all statements are recorded in the binary log. Each slave receives a copy of the entire contents of the binary log. It is the responsibility of the slave to decide which statements in the binary log should be executed; you cannot configure the master to log only certain events. If you do not specify otherwise, all events in the master binary log are executed on the slave. If required, you can configure the slave to process only events that apply to particular databases or tables. Each slave keeps a record of the binary log coordinates: The file name and position within the file that it has read and processed from the master. This means that multiple slaves can be connected to the master and executing different parts of the same binary log. Because the slaves control this process, individual slaves can be connected and disconnected from the server without affecting the master's operation. Also, because each slave remembers the position within the binary log, it is possible for slaves to be disconnected, reconnect and then `catch up' by continuing from the recorded position. Both the master and each slave must be configured with a unique ID (using the `server-id' option). In addition, each slave must be configured with information about the master host name, log file name, and position within that file. These details can be controlled from within a MySQL session using the *Note `CHANGE MASTER TO': change-master-to. statement on the slave. The details are stored within the slave's `master.info' file. This section describes the setup and configuration required for a replication environment, including step-by-step instructions for creating a new replication environment. The major components of this section are: * For a guide to setting up two or more servers for replication, *Note replication-howto::, deals with the configuration of the systems and provides methods for copying data between the master and slaves. * Events in the binary log are recorded using a number of formats. These are referred to as statement-based replication (SBR) or row-based replication (RBR). A third type, mixed-format replication (MIXED), uses SBR or RBR replication automatically to take advantage of the benefits of both SBR and RBR formats when appropriate. The different formats are discussed in *Note replication-formats::. * Detailed information on the different configuration options and variables that apply to replication is provided in *Note replication-options::. * Once started, the replication process should require little administration or monitoring. However, for advice on common tasks that you may want to execute, see *Note replication-administration::.  File: manual.info, Node: replication-howto, Next: replication-formats, Prev: replication-configuration, Up: replication-configuration 16.1.1 How to Set Up Replication -------------------------------- * Menu: * replication-howto-masterbaseconfig:: Setting the Replication Master Configuration * replication-howto-slavebaseconfig:: Setting the Replication Slave Configuration * replication-howto-repuser:: Creating a User for Replication * replication-howto-masterstatus:: Obtaining the Replication Master Binary Log Coordinates * replication-howto-mysqldump:: Creating a Data Snapshot Using `mysqldump' * replication-howto-rawdata:: Creating a Data Snapshot Using Raw Data Files * replication-howto-newservers:: Setting Up Replication with New Master and Slaves * replication-howto-existingdata:: Setting Up Replication with Existing Data * replication-howto-additionalslaves:: Introducing Additional Slaves to an Existing Replication Environment * replication-howto-slaveinit:: Setting the Master Configuration on the Slave This section describes how to set up complete replication of a MySQL server. There are a number of different methods for setting up replication, and the exact method to use depends on how you are setting up replication, and whether you already have data within your master database. There are some generic tasks that are common to all replication setups: * On the master, you must enable binary logging and configure a unique server ID. This might require a server restart. See *Note replication-howto-masterbaseconfig::. * On each slave that you want to connect to the master, you must configure a unique server ID. This might require a server restart. See *Note replication-howto-slavebaseconfig::. * You may want to create a separate user that will be used by your slaves to authenticate with the master to read the binary log for replication. The step is optional. See *Note replication-howto-repuser::. * Before creating a data snapshot or starting the replication process, you should record the position of the binary log on the master. You will need this information when configuring the slave so that the slave knows where within the binary log to start executing events. See *Note replication-howto-masterstatus::. * If you already have data on your master and you want to use it to synchronize your slave, you will need to create a data snapshot. You can create a snapshot using *Note `mysqldump': mysqldump. (see *Note replication-howto-mysqldump::) or by copying the data files directly (see *Note replication-howto-rawdata::). * You will need to configure the slave with settings for connecting to the master, such as the host name, login credentials, and binary log file name and position. See *Note replication-howto-slaveinit::. Once you have configured the basic options, you will need to follow the instructions for your replication setup. A number of alternatives are provided: * If you are establishing a new MySQL master and one or more slaves, you need only set up the configuration, as you have no data to exchange. For guidance on setting up replication in this situation, see *Note replication-howto-newservers::. * If you are already running a MySQL server, and therefore already have data that must be transferred to your slaves before replication starts, have not previously configured the binary log and are able to shut down your MySQL server for a short period during the process, see *Note replication-howto-existingdata::. * If you are adding slaves to an existing replication environment, you can set up the slaves without affecting the master. See *Note replication-howto-additionalslaves::. If you will be administering MySQL replication servers, we suggest that you read this entire chapter through and try all statements mentioned in *Note replication-master-sql::, and *Note replication-slave-sql::. You should also familiarize yourself with the replication startup options described in *Note replication-options::. *Note*: Note that certain steps within the setup process require the `SUPER' privilege. If you do not have this privilege, it might not be possible to enable replication.  File: manual.info, Node: replication-howto-masterbaseconfig, Next: replication-howto-slavebaseconfig, Prev: replication-howto, Up: replication-howto 16.1.1.1 Setting the Replication Master Configuration ..................................................... On a replication master, you must enable binary logging and establish a unique server ID. If this has not already been done, this part of master setup requires a server restart. Binary logging _must_ be enabled on the master because the binary log is the basis for sending data changes from the master to its slaves. If binary logging is not enabled, replication will not be possible. Each server within a replication group must be configured with a unique server ID. This ID is used to identify individual servers within the group, and must be a positive integer between 1 and (2^32)-1. How you organize and select the numbers is entirely up to you. To configure the binary log and server ID options, you will need to shut down your MySQL server and edit the `my.cnf' or `my.ini' file. Add the following options to the configuration file within the `[mysqld]' section. If these options already exist, but are commented out, uncomment the options and alter them according to your needs. For example, to enable binary logging using a log file name prefix of `mysql-bin', and configure a server ID of 1, use these lines: [mysqld] log-bin=mysql-bin server-id=1 After making the changes, restart the server. *Note*: If you omit `server-id' (or set it explicitly to its default value of 0), a master refuses connections from all slaves. *Note*: For the greatest possible durability and consistency in a replication setup using `InnoDB' with transactions, you should use `innodb_flush_log_at_trx_commit=1' and `sync_binlog=1' in the master `my.cnf' file. *Note*: Ensure that the `skip-networking' option is not enabled on your replication master. If networking has been disabled, your slave will not able to communicate with the master and replication will fail.  File: manual.info, Node: replication-howto-slavebaseconfig, Next: replication-howto-repuser, Prev: replication-howto-masterbaseconfig, Up: replication-howto 16.1.1.2 Setting the Replication Slave Configuration .................................................... On a replication slave, you must establish a unique server ID. If this has not already been done, this part of slave setup requires a server restart. If the slave server ID is not already set, or the current value conflicts with the value that you have chosen for the master server, you should shut down your slave server and edit the configuration to specify a unique server ID. For example: [mysqld] server-id=2 After making the changes, restart the server. If you are setting up multiple slaves, each one must have a unique `server-id' value that differs from that of the master and from each of the other slaves. Think of `server-id' values as something similar to IP addresses: These IDs uniquely identify each server instance in the community of replication partners. *Note*: If you omit `server-id' (or set it explicitly to its default value of 0), a slave refuses to connect to a master. You do not have to enable binary logging on the slave for replication to be enabled. However, if you enable binary logging on the slave, you can use the binary log for data backups and crash recovery on the slave, and also use the slave as part of a more complex replication topology (for example, where the slave acts as a master to other slaves).  File: manual.info, Node: replication-howto-repuser, Next: replication-howto-masterstatus, Prev: replication-howto-slavebaseconfig, Up: replication-howto 16.1.1.3 Creating a User for Replication ........................................ Each slave must connect to the master using a MySQL user name and password, so there must be a user account on the master that the slave can use to connect. Any account can be used for this operation, providing it has been granted the `REPLICATION SLAVE' privilege. You may wish to create a different account for each slave, or connect to the master using the same account for each slave. You need not create an account specifically for replication. However, you should be aware that the user name and password will be stored in plain text within the `master.info' file (see *Note slave-logs-status::). Therefore, you may want to create a separate account that has privileges only for the replication process, to minimize the possibility of compromise to other accounts. To create a new acccount, use *Note `CREATE USER': create-user. To grant this account the privileges required for replication, use the *Note `GRANT': grant. statement. If you create an account solely for the purposes of replication, that account needs only the `REPLICATION SLAVE' privilege. For example, to set up a new user, `repl', that can connect for replication from any host within the `mydomain.com' domain, issue these statements on the master: mysql> CREATE USER 'repl'@'%.mydomain.com' IDENTIFIED BY 'slavepass'; mysql> GRANT REPLICATION SLAVE ON *.* TO 'repl'@'%.mydomain.com'; See *Note account-management-sql::, for more information on statements for manipulation of user accounts.  File: manual.info, Node: replication-howto-masterstatus, Next: replication-howto-mysqldump, Prev: replication-howto-repuser, Up: replication-howto 16.1.1.4 Obtaining the Replication Master Binary Log Coordinates ................................................................ To configure replication on the slave you must determine the master's current coordinates within its binary log. You will need this information so that when the slave starts the replication process, it is able to start processing events from the binary log at the correct point. If you have existing data on your master that you want to synchronize on your slaves before starting the replication process, you must stop processing statements on the master, and then obtain its current binary log coordinates and dump its data, before permitting the master to continue executing statements. If you do not stop the execution of statements, the data dump and the master status information that you use will not match and you will end up with inconsistent or corrupted databases on the slaves. To obtain the master binary log coordinates, follow these steps: 1. Start a session on the master by connecting to it with the command-line client, and flush all tables and block write statements by executing the *Note `FLUSH TABLES WITH READ LOCK': flush. statement: mysql> FLUSH TABLES WITH READ LOCK; For `InnoDB' tables, note that *Note `FLUSH TABLES WITH READ LOCK': flush. also blocks *Note `COMMIT': commit. operations. *Warning*: Leave the client from which you issued the *Note `FLUSH TABLES': flush. statement running so that the read lock remains in effect. If you exit the client, the lock is released. 2. In a different session on the master, use the *Note `SHOW MASTER STATUS': show-master-status. statement to determine the current binary log file name and position: mysql > SHOW MASTER STATUS; +------------------+----------+--------------+------------------+ | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | +------------------+----------+--------------+------------------+ | mysql-bin.000003 | 73 | test | manual,mysql | +------------------+----------+--------------+------------------+ The `File' column shows the name of the log file and `Position' shows the position within the file. In this example, the binary log file is `mysql-bin.000003' and the position is 73. Record these values. You need them later when you are setting up the slave. They represent the replication coordinates at which the slave should begin processing new updates from the master. If the master has been running previously without binary logging enabled, the log file name and position values displayed by *Note `SHOW MASTER STATUS': show-master-status. or *Note `mysqldump --master-data': mysqldump. will be empty. In that case, the values that you need to use later when specifying the slave's log file and position are the empty string (`''') and `4'. You now have the information you need to enable the slave to start reading from the binary log in the correct place to start replication. If you have existing data that needs be to synchronized with the slave before you start replication, leave the client running so that the lock remains in place and then proceed to *Note replication-howto-mysqldump::, or *Note replication-howto-rawdata::. The idea here is to prevent any further changes so that the data copied to the slaves is in synchrony with the master. If you are setting up a brand new master and slave replication group, you can exit the first session to release the read lock.  File: manual.info, Node: replication-howto-mysqldump, Next: replication-howto-rawdata, Prev: replication-howto-masterstatus, Up: replication-howto 16.1.1.5 Creating a Data Snapshot Using `mysqldump' ................................................... One way to create a snapshot of the data in an existing master database is to use the *Note `mysqldump': mysqldump. tool. Once the data dump has been completed, you then import this data into the slave before starting the replication process. To obtain a snapshot of the data using *Note `mysqldump': mysqldump.: 1. If you have not already locked the tables on the server to prevent statements that update data from executing: Start a session on the server by connecting to it with the command-line client, and flush all tables and block write statements by executing the *Note `FLUSH TABLES WITH READ LOCK': flush. statement: mysql> FLUSH TABLES WITH READ LOCK; Remember to use *Note `SHOW MASTER STATUS': show-master-status. and record the binary log details for use when starting up the slave. The point in time of your snapshot and the binary log position must match. See *Note replication-howto-masterstatus::. 2. In another session, use *Note `mysqldump': mysqldump. to create a dump either of all the databases you want to replicate, or of selected individual databases. For example: shell> mysqldump --all-databases --lock-all-tables >dbdump.db An alternative to using a bare dump, is to use the `--master-data' option, which automatically appends the *Note `CHANGE MASTER TO': change-master-to. statement required on the slave to start the replication process. shell> mysqldump --all-databases --master-data >dbdump.db 3. In the client where you acquired the read lock, release the lock: mysql> UNLOCK TABLES; Alternatively, exit the first session to release the read lock. When choosing databases to include in the dump, remember that you will need to filter out databases on each slave that you do not want to include in the replication process. You will need either to copy the dump file to the slave, or to use the file from the master when connecting remotely to the slave to import the data.  File: manual.info, Node: replication-howto-rawdata, Next: replication-howto-newservers, Prev: replication-howto-mysqldump, Up: replication-howto 16.1.1.6 Creating a Data Snapshot Using Raw Data Files ...................................................... If your database is particularly large, copying the raw data files may be more efficient than using *Note `mysqldump': mysqldump. and importing the file on each slave. However, using this method with tables in storage engines with complex caching or logging algorithms may not give you a perfect `in time' snapshot as cache information and logging updates may not have been applied, even if you have acquired a global read lock. How the storage engine responds to this depends on its crash recovery abilities. In addition, this method does not work reliably if the master and slave have different values for `ft_stopword_file', `ft_min_word_len', or `ft_max_word_len' and you are copying tables having full-text indexes. If you are using `InnoDB' tables, you can use the ``InnoDB' Hot Backup' tool to obtain a consistent snapshot. This tool records the log name and offset corresponding to the snapshot to be later used on the slave. `Hot Backup' is a nonfree (commercial) tool that is not included in the standard MySQL distribution. See the ``InnoDB' Hot Backup' home page at `http://www.innodb.com/wp/products/hot-backup/' for detailed information. Otherwise, you can obtain a reliable binary snapshot of `InnoDB' tables only after shutting down the MySQL Server. To create a raw data snapshot of `MyISAM' tables you can use standard copy tools such as `cp' or `copy', a remote copy tool such as `scp' or `rsync', an archiving tool such as `zip' or `tar', or a file system snapshot tool such as `dump', providing that your MySQL data files exist on a single file system. If you are replicating only certain databases then make sure you copy only those files that related to those tables. (For `InnoDB', all tables in all databases are stored in the shared tablespace files, unless you have the `innodb_file_per_table' option enabled.) You may want to specifically exclude the following files from your archive: * Files relating to the `mysql' database. * The `master.info' file. * The master's binary log files. * Any relay log files. To get the most consistent results with a raw data snapshot you should shut down the master server during the process, as follows: 1. Acquire a read lock and get the master's status. See *Note replication-howto-masterstatus::. 2. In a separate session, shut down the master server: shell> mysqladmin shutdown 3. Make a copy of the MySQL data files. The following examples show common ways to do this. You need to choose only one of them: shell> tar cf /TMP/DB.TAR ./DATA shell> zip -r /TMP/DB.ZIP ./DATA shell> rsync --recursive ./DATA /TMP/DBDATA 4. Restart the master server. If you are not using `InnoDB' tables, you can get a snapshot of the system from a master without shutting down the server as described in the following steps: 1. Acquire a read lock and get the master's status. See *Note replication-howto-masterstatus::. 2. Make a copy of the MySQL data files. The following examples show common ways to do this. You need to choose only one of them: shell> tar cf /TMP/DB.TAR ./DATA shell> zip -r /TMP/DB.ZIP ./DATA shell> rsync --recursive ./DATA /TMP/DBDATA 3. In the client where you acquired the read lock, release the lock: mysql> UNLOCK TABLES; Once you have created the archive or copy of the database, you will need to copy the files to each slave before starting the slave replication process.  File: manual.info, Node: replication-howto-newservers, Next: replication-howto-existingdata, Prev: replication-howto-rawdata, Up: replication-howto 16.1.1.7 Setting Up Replication with New Master and Slaves .......................................................... The easiest and most straightforward method for setting up replication is to use new master and slave servers. You can also use this method if you are setting up new servers but have an existing dump of the databases from a different server that you want to load into your replication configuration. By loading the data into a new master, the data will be automatically replicated to the slaves. To set up replication between a new master and slave: 1. Configure the MySQL master with the necessary configuration properties. See *Note replication-howto-masterbaseconfig::. 2. Start up the MySQL master. 3. Set up a user. See *Note replication-howto-repuser::. 4. Obtain the master status information. See *Note replication-howto-masterstatus::. 5. On the master, release the read lock: mysql> UNLOCK TABLES; 6. On the slave, edit the MySQL configuration. See *Note replication-howto-slavebaseconfig::. 7. Start up the MySQL slave. 8. Execute a *Note `CHANGE MASTER TO': change-master-to. statement to set the master replication server configuration. See *Note replication-howto-slaveinit::. Perform the slave setup steps on each slave. Because there is no data to load or exchange on a new server configuration you do not need to copy or import any information. If you are setting up a new replication environment using the data from a different existing database server, you will now need to run the dump file generated from that server on the new master. The database updates will automatically be propagated to the slaves: shell> mysql -h master < fulldb.dump  File: manual.info, Node: replication-howto-existingdata, Next: replication-howto-additionalslaves, Prev: replication-howto-newservers, Up: replication-howto 16.1.1.8 Setting Up Replication with Existing Data .................................................. When setting up replication with existing data, you will need to decide how best to get the data from the master to the slave before starting the replication service. The basic process for setting up replication with existing data is as follows: 1. With the MySQL master running, create a user to be used by the slave when connecting to the master during replication. See *Note replication-howto-repuser::. 2. If you have not already configured the `server-id' and enabled binary logging on the master server, you will need to shut it down to configure these options. See *Note replication-howto-masterbaseconfig::. If you have to shut down your master server, this is a good opportunity to take a snapshot of its databases. You should obtain the master status (see *Note replication-howto-masterstatus::) before taking down the master, updating the configuration and taking a snapshot. For information on how to create a snapshot using raw data files, see *Note replication-howto-rawdata::. 3. If your master server is already correctly configured, obtain its status (see *Note replication-howto-masterstatus::) and then use *Note `mysqldump': mysqldump. to take a snapshot (see *Note replication-howto-mysqldump::) or take a raw snapshot of the live server using the guide in *Note replication-howto-rawdata::. 4. Update the configuration of the slave. See *Note replication-howto-slavebaseconfig::. 5. The next step depends on how you created the snapshot of data on the master. If you used *Note `mysqldump': mysqldump.: 1. Start the slave, using the `--skip-slave-start' option so that replication does not start. 2. Import the dump file: shell> mysql < fulldb.dump If you created a snapshot using the raw data files: 1. Extract the data files into your slave data directory. For example: shell> tar xvf dbdump.tar You may need to set permissions and ownership on the files so that the slave server can access and modify them. 2. Start the slave, using the `--skip-slave-start' option so that replication does not start. 6. Configure the slave with the replication coordinates from the master. This tells the slave the binary log file and position within the file where replication needs to start. Also, configure the slave with the login credentials and host name of the master. For more information on the *Note `CHANGE MASTER TO': change-master-to. statement required, see *Note replication-howto-slaveinit::. 7. Start the slave threads: mysql> START SLAVE; After you have performed this procedure, the slave should connect to the master and catch up on any updates that have occurred since the snapshot was taken. If you have forgotten to set the `server-id' option for the master, slaves cannot connect to it. If you have forgotten to set the `server-id' option for the slave, you get the following error in the slave's error log: Warning: You should set server-id to a non-0 value if master_host is set; we will force server id to 2, but this MySQL server will not act as a slave. You also find error messages in the slave's error log if it is not able to replicate for any other reason. Once a slave is replicating, you can find in its data directory one file named `master.info' and another named `relay-log.info'. The slave uses these two files to keep track of how much of the master's binary log it has processed. Do _not_ remove or edit these files unless you know exactly what you are doing and fully understand the implications. Even in that case, it is preferred that you use the *Note `CHANGE MASTER TO': change-master-to. statement to change replication parameters. The slave will use the values specified in the statement to update the status files automatically. *Note*: The content of `master.info' overrides some of the server options specified on the command line or in `my.cnf'. See *Note replication-options::, for more details. A single snapshot of the master suffices for multiple slaves. To set up additional slaves, use the same master snapshot and follow the slave portion of the procedure just described.  File: manual.info, Node: replication-howto-additionalslaves, Next: replication-howto-slaveinit, Prev: replication-howto-existingdata, Up: replication-howto 16.1.1.9 Introducing Additional Slaves to an Existing Replication Environment ............................................................................. To add another slave to an existing replication configuration, you can do so without stopping the master. Instead, set up the new slave by making a copy of an existing slave, except that you configure the new slave with a different `server-id' value. To duplicate an existing slave: 1. Shut down the existing slave: shell> mysqladmin shutdown 2. Copy the data directory from the existing slave to the new slave. You can do this by creating an archive using `tar' or `WinZip', or by performing a direct copy using a tool such as `cp' or `rsync'. Ensure that you also copy the log files and relay log files. A common problem that is encountered when adding new replication slaves is that the new slave fails with a series of warning and error messages like these: 071118 16:44:10 [Warning] Neither --relay-log nor --relay-log-index were used; so replication may break when this MySQL server acts as a slave and has his hostname changed!! Please use '--relay-log=NEW_SLAVE_HOSTNAME-relay-bin' to avoid this problem. `071118 16:44:10 [ERROR] Failed to open the relay log './OLD_SLAVE_HOSTNAME-relay-bin.003525' (relay_log_pos 22940879)' 071118 16:44:10 `[ERROR] Could not find target log during relay log initialization' 071118 16:44:10 `[ERROR] Failed to initialize the master info structure' This is due to the fact that, if the `--relay-log' option is not specified, the relay log files contain the host name as part of their file names. (This is also true of the relay log index file if the `--relay-log-index' option is not used. See *Note replication-options::, for more information about these options.) To avoid this problem, use the same value for `--relay-log' on the new slave that was used on the existing slave. (If this option was not set explicitly on the existing slave, use `EXISTING_SLAVE_HOSTNAME-relay-bin'.) If this is not feasible, copy the existing slave's relay log index file to the new slave and set the `--relay-log-index' option on the new slave to match what was used on the existing slave. (If this option was not set explicitly on the existing slave, use `EXISTING_SLAVE_HOSTNAME-relay-bin.index'.) Alternatively--if you have already tried to start the new slave (after following the remaining steps in this section) and have encountered errors like those described previously--then perform the following steps: 1. If you have not already done so, issue a *Note `STOP SLAVE': stop-slave. on the new slave. If you have already started the existing slave again, issue a *Note `STOP SLAVE': stop-slave. on the existing slave as well. 2. Copy the contents of the existing slave's relay log index file into the new slave's relay log index file, making sure to overwrite any content already in the file. 3. Proceed with the remaining steps in this section. 3. Copy the `master.info' and `relay-log.info' files from the existing slave to the new slave if they were not located in the data directory. These files hold the current log coordinates for the master's binary log and the slave's relay log. 4. Start the existing slave. 5. On the new slave, edit the configuration and give the new slave a unique `server-id' not used by the master or any of the existing slaves. 6. Start the new slave. The slave will use the information in its `master.info' file to start the replication process.  File: manual.info, Node: replication-howto-slaveinit, Prev: replication-howto-additionalslaves, Up: replication-howto 16.1.1.10 Setting the Master Configuration on the Slave ....................................................... To set up the slave to communicate with the master for replication, you must tell the slave the necessary connection information. To do this, execute the following statement on the slave, replacing the option values with the actual values relevant to your system: mysql> CHANGE MASTER TO -> MASTER_HOST='MASTER_HOST_NAME', -> MASTER_USER='REPLICATION_USER_NAME', -> MASTER_PASSWORD='REPLICATION_PASSWORD', -> MASTER_LOG_FILE='RECORDED_LOG_FILE_NAME', -> MASTER_LOG_POS=RECORDED_LOG_POSITION; *Note*: Replication cannot use Unix socket files. You must be able to connect to the master MySQL server using TCP/IP. The *Note `CHANGE MASTER TO': change-master-to. statement has other options as well. For example, it is possible to set up secure replication using SSL. For a full list of options, and information about the maximum permissible length for the string-valued options, see *Note change-master-to::.  File: manual.info, Node: replication-formats, Next: replication-options, Prev: replication-howto, Up: replication-configuration 16.1.2 Replication Formats -------------------------- * Menu: * replication-sbr-rbr:: Comparison of Statement-Based and Row-Based Replication * replication-rbr-usage:: Usage of Row-Based Logging and Replication * replication-rbr-safe-unsafe:: Safe and Unsafe Statements in Logging and Replication Replication works because events written to the binary log are read from the master and then processed on the slave. The events are recorded within the binary log in different formats according to the type of event. The different replication formats used correspond to the binary logging format used when the events were recorded in the master's binary log. The correlation between binary logging formats and the terms used during replication are: * Replication capabilities in MySQL originally were based on propagation of SQL statements from master to slave. This is called _statement-based replication_ (often abbreviated as _SBR_), which corresponds to the standard statement-based binary logging format. In MySQL 5.1.4 and earlier, binary logging and replication used this format exclusively. * Row-based binary logging logs changes in individual table rows. When used with MySQL replication, this is known as _row-based replication_ (often abbreviated as _RBR_). In row-based replication, the master writes _events_ to the binary log that indicate how individual table rows are changed. * As of MySQL 5.1.8, the server can change the binary logging format in real time according to the type of event using _mixed-format logging_. When the mixed format is in effect, statement-based logging is used by default, but automatically switches to row-based logging in particular cases as described later. Replication using the mixed format is often referred to as _mixed-based replication_ or _mixed-format replication_. For more information, see *Note binary-log-mixed::. From MySQL 5.1.12 to MySQL 5.1.28, mixed format is the default. Beginning with MySQL 5.1.29, statement-based format is the default. MySQL Cluster The default binary logging format in all MySQL Cluster NDB 6.x and 7.x releases is `ROW'. MySQL Cluster Replication always uses row-based replication, and the *Note `NDBCLUSTER': mysql-cluster. storage engine is incompatible with statement-based replication. Using *Note `NDBCLUSTER': mysql-cluster. sets row-based logging format automatically. See *Note mysql-cluster-replication-general::, for more information. Starting with MySQL 5.1.20, when using `MIXED' format, the binary logging format is determined in part by the storage engine being used and the statement being executed. For more information on mixed-format logging and the rules governing the support of different logging formats, see *Note binary-log-mixed::. The logging format in a running MySQL server is controlled by setting the `binlog_format' server system variable. This variable can be set with session or global scope. The rules governing when and how the new setting takes effect are the same as for other MySQL server system variables--setting the variable for the current session lasts only until the end of that session, and the change is not visible to other sessions; setting the variable globally requires a restart of the server to take effect. For more information, see *Note set-option::. You must have the `SUPER' privilege to set the global `binlog_format' value. Starting with MySQL 5.1.29, you must have the `SUPER' privilege to set either the global or session `binlog_format' value. (Bug#39106) The statement-based and row-based replication formats have different issues and limitations. For a comparison of their relative advantages and disadvantages, see *Note replication-sbr-rbr::. With statement-based replication, you may encounter issues with replicating stored routines or triggers. You can avoid these issues by using row-based replication instead. For more information, see *Note stored-programs-logging::.  File: manual.info, Node: replication-sbr-rbr, Next: replication-rbr-usage, Prev: replication-formats, Up: replication-formats 16.1.2.1 Comparison of Statement-Based and Row-Based Replication ................................................................ Each binary logging format has advantages and disadvantages. For most users, the mixed replication format should provide the best combination of data integrity and performance. If, however, you want to take advantage of the features specific to the statement-based or row-based replication format when performing certain tasks, you can use the information in this section, which provides a summary of their relative advantages and disadvantages, to determine which is best for your needs. *Advantages of statement-based replication:* * Proven technology that has existed in MySQL since 3.23. * Less data written to log files. When updates or deletes affect many rows, this results in _much_ less storage space required for log files. This also means that taking and restoring from backups can be accomplished more quickly. * Log files contain all statements that made any changes, so they can be used to audit the database. *Disadvantages of statement-based replication:* * Statements that are unsafe for SBR Not all statements which modify data (such as *Note `INSERT': insert. *Note `DELETE': delete, *Note `UPDATE': update, and `REPLACE' statements) can be replicated using statement-based replication. Any nondeterministic behavior is difficult to replicate when using statement-based replication. Examples of such DML (Data Modification Language) statements include the following: * A statement that depends on a UDF or stored program that is nondeterministic, since the value returned by such a UDF or stored program or depends on factors other than the parameters supplied to it. (Row-based replication, however, simply replicates the value returned by the UDF or stored program, so its effect on table rows and data is the same on both the master and slave.) See *Note replication-features-invoked::, for more information. * *Note `DELETE': delete. and *Note `UPDATE': update. statements that use a `LIMIT' clause without an `ORDER BY' are nondeterministic. See *Note replication-features-limit::. * Statements using any of the following functions cannot be replicated properly using statement-based replication: * `LOAD_FILE()' * `UUID()', `UUID_SHORT()' * `USER()' * `FOUND_ROWS()' * `SYSDATE()' (unless both the master and the slave are started with the `--sysdate-is-now' option) * `GET_LOCK()' * `IS_FREE_LOCK()' * `IS_USED_LOCK()' * `MASTER_POS_WAIT()' * `RELEASE_LOCK()' * `SLEEP()' * `VERSION()' However, all other functions are replicated correctly using statement-based replication, including `RAND()', `NOW()', and so forth. For more information, see *Note replication-features-functions::. Statements that cannot be replicated correctly using statement-based replication are logged with a warning like the one shown here: 090213 16:58:54 [Warning] Statement is not safe to log in statement format. A similar warning is also issued to the client in such cases. The client can display it using *Note `SHOW WARNINGS': show-warnings. * *Note `INSERT ... SELECT': insert. requires a greater number of row-level locks than with row-based replication. * *Note `UPDATE': update. statements that require a table scan (because no index is used in the `WHERE' clause) must lock a greater number of rows than with row-based replication. * For *Note `InnoDB': innodb-storage-engine.: An *Note `INSERT': insert. statement that uses `AUTO_INCREMENT' blocks other nonconflicting *Note `INSERT': insert. statements. * For complex statements, the statement must be evaluated and executed on the slave before the rows are updated or inserted. With row-based replication, the slave only has to modify the affected rows, not execute the full statement. * If there is an error in evaluation on the slave, particularly when executing complex statements, statement-based replication may slowly increase the margin of error across the affected rows over time. See *Note replication-features-slaveerrors::. * Stored functions execute with the same `NOW()' value as the calling statement. However, this is not true of stored procedures. * Deterministic UDFs must be applied on the slaves. * Table definitions must be (nearly) identical on master and slave. See *Note replication-features-differing-tables::, for more information. *Advantages of row-based replication:* * All changes can be replicated. This is the safest form of replication. For MySQL versions earlier than 5.1.14, DDL (Data Definition Language) statements such as *Note `CREATE TABLE': create-table. are replicated using statement-based replication, while DML statements, as well as *Note `GRANT': grant. and *Note `REVOKE': revoke. statements, are replicated using row-based replication. In MySQL 5.1.14 and later, the `mysql' database is not replicated. The `mysql' database is instead seen as a node-specific database. Row-based replication is not supported on tables in this database. Instead, statements that would normally update this information--such as *Note `GRANT': grant, *Note `REVOKE': revoke. and the manipulation of triggers, stored routines (including stored procedures), and views--are all replicated to slaves using statement-based replication. For statements such as *Note `CREATE TABLE ... SELECT': create-table, a `CREATE' statement is generated from the table definition and replicated using statement-based format, while the row insertions are replicated using row-based format. * The technology is the same as in most other database management systems; knowledge about other systems transfers to MySQL. * Fewer row locks are required on the master, which thus achieves higher concurrency, for the following types of statements: * *Note `INSERT ... SELECT': insert-select. * *Note `INSERT': insert. statements with `AUTO_INCREMENT' * *Note `UPDATE': update. or *Note `DELETE': delete. statements with `WHERE' clauses that do not use keys or do not change most of the examined rows. * Fewer row locks are required on the slave for any *Note `INSERT': insert, *Note `UPDATE': update, or *Note `DELETE': delete. statement. *Disadvantages of row-based replication:* * RBR tends to generate more data that must be logged. To replicate a DML statement (such as an *Note `UPDATE': update. or *Note `DELETE': delete. statement), statement-based replication writes only the statement to the binary log. By contrast, row-based replication writes each changed row to the binary log. If the statement changes many rows, row-based replication may write significantly more data to the binary log; this is true even for statements that are rolled back. This also means that taking and restoring from backup can require more time. In addition, the binary log is locked for a longer time to write the data, which may cause concurrency problems. * Deterministic UDFs that generate large *Note `BLOB': blob. values take longer to replicate with row-based replication than with statement-based replication. This is because the *Note `BLOB': blob. column value is logged, rather than the statement generating the data. * You cannot examine the logs to see what statements were executed, nor can you see on the slave what statements were received from the master and executed. However, beginning with MySQL 5.1.29, you can see what data was changed using *Note `mysqlbinlog': mysqlbinlog. with the options `--base64-output=DECODE-ROWS' and `--verbose'. * Formerly, when performing a bulk operation that includes nontransactional storage engines, changes were applied as the statement executed. With row-based logging, this meant that the binary log was written while the statement was running. On the master, this does not cause problems with concurrency, because tables are locked until the bulk operation terminates. On the slave server, tables were not locked while the slave applied changes, because the slave did not know that those changes were part of a bulk operation. In such cases, if you retrieved data from a table on the master (for example, using `SELECT * FROM table_name'), the server waited for the bulk operation to complete before executing the *Note `SELECT': select. statement, because the table was read-locked. On the slave, the server did not wait (because there was no lock). This meant that, until the bulk operation on the slave completed, different results were obtained for the same *Note `SELECT': select. query on the master and on the slave. This issue was resolved in MySQL 5.1.24. (Bug#29020)  File: manual.info, Node: replication-rbr-usage, Next: replication-rbr-safe-unsafe, Prev: replication-sbr-rbr, Up: replication-formats 16.1.2.2 Usage of Row-Based Logging and Replication ................................................... Major changes in the replication environment and in the behavior of applications can result from using row-based logging (RBL) or row-based replication (RBR) rather than statement-based logging or replication. This section describes a number of issues known to exist when using row-based logging or replication, and discusses some best practices for taking advantage of row-based logging and replication. For additional information, see *Note replication-formats::, and *Note replication-sbr-rbr::. For information about issues specific to MySQL Cluster Replication (which depends on row-based replication), see *Note mysql-cluster-replication-issues::. * RBL, RBR, and temporary tables As noted in *Note replication-features-temptables::, temporary tables are not replicated when using row-based format. When mixed format is in effect, `safe' statements involving temporary tables are logged using statement-based format. For more information, see *Note replication-sbr-rbr::. *Note*: Temporary tables are not replicated when using row-based format because there is no need. In addition, because temporary tables can be read only from the thread which created them, there is seldom if ever any benefit obtained from replicating them, even when using statement-based format. * RBL and the `BLACKHOLE' storage engine Prior to MySQL 5.1.29, *Note `DELETE': delete. and *Note `UPDATE': update. statements for `BLACKHOLE' tables did not work with RBL. (Bug#38360) * RBL and synchronization of nontransactional tables When many rows are affected, the set of changes is split into several events; when the statement commits, all of these events are written to the binary log if the statement is an initial nontransactional statement (occurring in the transaction before any transactional statements). When executing on the slave, a table lock is taken on all tables involved, and then the rows are applied in batch mode. (This may or may not be effective, depending on the engine used for the slave's copy of the table.) * Latency and binary log size Because RBL writes changes for each row to the binary log, its size can increase quite rapidly. In a replication environment, this can significantly increase the time required to make changes on the slave that match those on the master. You should be aware of the potential for this delay in your applications. * Reading the binary log *Note `mysqlbinlog': mysqlbinlog. displays row-based events in the binary log using the `BINLOG' statement (see *Note binlog::). This statement displays an event in printable form, but as a base 64-encoded string the meaning of which is not evident. As of MySQL 5.1.28, when invoked with the `--base64-output=DECODE-ROWS' and `--verbose' options, *Note `mysqlbinlog': mysqlbinlog. formats the contents of the binary log in a manner that is easily human readable. This is helpful when binary log events were written in row-based format if you want to read or recover from a replication or database failure using the contents of the binary log. For more information, see *Note mysqlbinlog-row-events::. * Binary log execution errors and `slave_exec_mode' If `slave_exec_mode' is `IDEMPOTENT', a failure to apply changes from RBL because the original row cannot be found does not trigger an error or cause replication to fail. This means that it is possible that updates are not applied on the slave, so that the master and slave are no longer synchronized. Latency issues and use of nontransactional tables with RBR when `slave_exec_mode' is `IDEMPOTENT' can cause the master and slave to diverge even further. For more information about `slave_exec_mode', see *Note server-system-variables::. *Note*: `slave_exec_mode=IDEMPOTENT' is generally useful only for circular replication or multi-master replication with MySQL Cluster, for which `IDEMPOTENT' is the default value (see *Note mysql-cluster-replication::). For other scenarios, setting `slave_exec_mode' to `STRICT' is normally sufficient; this is the default value for storage engines other than *Note `NDB': mysql-cluster. * Lack of binary log checksums RBL uses no checksums. This means that network, disk, and other errors may not be identified when processing the binary log. To ensure that data is transmitted without network corruption, you may want to consider using SSL, which adds another layer of checksumming, for replication connections. The *Note `CHANGE MASTER TO': change-master-to. statement has options to enable replication over SSL. See also *Note change-master-to::, for general information about setting up MySQL with SSL. * Filtering based on server ID not supported A common practice is to filter out changes on some slaves by using a `WHERE' clause that includes the relation `@@server_id <> ID_VALUE' clause with *Note `UPDATE': update. and *Note `DELETE': delete. statements, a simple example of such a clause being `WHERE @@server_id <> 1'. However, this does not work correctly with row-based logging. If you must use the `server_id' system variable for statement filtering, you must also use `--binlog_format=STATEMENT'. * Database-level replication options The effects of the `--replicate-do-db', `--replicate-ignore-db', and `--replicate-rewrite-db' options differ considerably depending on whether row-based or statement-based logging is used. Because of this, it is recommended to avoid database-level options and instead use table-level options such as `--replicate-do-table' and `--replicate-ignore-table'. For more information about these options and the impact that your choice of replication format has on how they operate, see *Note replication-options::.  File: manual.info, Node: replication-rbr-safe-unsafe, Prev: replication-rbr-usage, Up: replication-formats 16.1.2.3 Safe and Unsafe Statements in Logging and Replication .............................................................. When speaking of the `safeness' of a statement in MySQL Replication, we are referring to whether a statement and its effects can be replicated correctly using statement-based format. If this is true of the statement, we refer to the statement as _safe_; otherwise, we refer to it as _unsafe_. In general, a statement is safe if it deterministic, and unsafe if it is not. However, certain nondeterministic functions are _not_ considered unsafe (see *Note replication-rbr-safe-unsafe-not::, later in this section). In addition, statements using results from floating-point math functions--which are hardware-dependent--are always considered safe (see *Note replication-features-floatvalues::). Handling of safe and unsafe statements A statement is treated differently depending on whether the statement is considered safe, and with respect to the binary logging format (that is, the current value of `binlog_format'). * No distinction is made in the treatment of safe and unsafe statements when the binary logging mode is `ROW'. * If the binary logging format is `MIXED', statements flagged as unsafe are logged using the row-based format; statements regarded as safe are logged using the statement-based format. * If the binary logging format is `STATEMENT', statements flagged as being unsafe generate a warning to this effect. (Safe statements are logged normally.) For more information, see *Note replication-formats::. Statements considered unsafe Statements having the following characteristics are considered unsafe: * Statements containing system functions that may return a different value on slave. These functions include `FOUND_ROWS()', `GET_LOCK()', `IS_FREE_LOCK()', `IS_USED_LOCK()', `LOAD_FILE()', `MASTER_POS_WAIT()', `RELEASE_LOCK()', `ROW_COUNT()', `SESSION_USER()', `SLEEP()', `SYSDATE()', `SYSTEM_USER()', `USER()', `UUID()', and `UUID_SHORT()'. Nondeterministic functions not considered unsafe Although these functions are not deterministic, they are treated as safe for purposes of logging and replication: `CONNECTION_ID()', `CURDATE()', `CURRENT_DATE()', `CURRENT_TIME()', `CURRENT_TIMESTAMP()', `CURTIME()', `LOCALTIME()', `LOCALTIMESTAMP()', `NOW()', `UNIX_TIMESTAMP()', `UTC_DATE()', `UTC_TIME()', `UTC_TIMESTAMP()', and `LAST_INSERT_ID()' For more information, see *Note replication-features-functions::. * References to system variables Most system variables are not replicated correctly using the statement-based format. For exceptions, see *Note binary-log-mixed::. See *Note replication-features-variables::. * UDFs Since we have no control over what a UDF does, we must assume that it is executing unsafe statements. * Updates a table having an `AUTO_INCREMENT' column This is unsafe because the order in which the rows are updated may differ on the master and the slave. For more information, see *Note replication-features-auto-increment::. * `INSERT DELAYED' statement This statement is considered unsafe because the insertion of the rows may interleave with concurrently executing statements. * Updates using `LIMIT' The order in which rows are retrieved is not specified. See *Note replication-features-limit::. * Accesses or references log tables The contents of the system log table may differ between master and slave. * Nontransactional operations after transactional operations Within a transaction, allowing any nontransactional reads or writes to execute after any transactional reads or writes is considered unsafe. For more information, see *Note replication-features-transactions::. * Accesses or references self-logging tables All reads and writes to self-logging tables are considered unsafe. Within a transaction, any statement following a read or write to self-logging tables is also considered unsafe. * `LOAD DATA INFILE' statements Beginning with MySQL 5.1.50, *Note `LOAD DATA INFILE': load-data. is considered unsafe, it causes a warning in statement-based mode, and a switch to row-based format when using mixed-format logging. See *Note replication-features-load-data::. For additional information, see *Note replication-features::.  File: manual.info, Node: replication-options, Next: replication-administration, Prev: replication-formats, Up: replication-configuration 16.1.3 Replication and Binary Logging Options and Variables ----------------------------------------------------------- * Menu: * replication-options-table:: Replication and Binary Logging Option and Variable Reference * replication-options-master:: Replication Master Options and Variables * replication-options-slave:: Replication Slave Options and Variables * replication-options-binary-log:: Binary Log Options and Variables The next few sections contain information about *Note `mysqld': mysqld. options and server variables that are used in replication and for controlling the binary log. Options and variables for use on replication masters and replication slaves are covered separately, as are options and variables relating to binary logging. A set of quick-reference tables providing basic information about these options and variables is also included (in the next section following this one). Of particular importance is the `--server-id' option. Options for server-id *Command-Line Format* `--server-id=#' *Option-File Format* `server-id' *Option Sets Variable* Yes, `server_id' *Variable Name* `server_id' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `numeric' *Default* `0' *Range* `0-4294967295' This option is common to both master and slave replication servers, and is used in replication to enable master and slave servers to identify themselves uniquely. For additional information, see *Note replication-options-master::, and *Note replication-options-slave::. On the master and each slave, you _must_ use the `--server-id' option to establish a unique replication ID in the range from 1 to 2^32 - 1. `Unique', means that each ID must be different from every other ID in use by any other replication master or slave. Example: `server-id=3'. If you omit `--server-id', the default ID is 0, in which case a master refuses connections from all slaves, and a slave refuses to connect to a master. For more information, see *Note replication-howto-slavebaseconfig::.  File: manual.info, Node: replication-options-table, Next: replication-options-master, Prev: replication-options, Up: replication-options 16.1.3.1 Replication and Binary Logging Option and Variable Reference ..................................................................... The following tables list basic information about the MySQL command-line options and system variables applicable to replication and the binary log. *Replication Option/Variable Summary* Name Cmd-Line Option file System Var Status Var Var Scope Dynamic abort-slave-event-countYes Yes Com_change_master Yes Both No Com_show_master_status Yes Both No Com_show_new_master Yes Both No Com_show_slave_hosts Yes Both No Com_show_slave_status Yes Both No Com_slave_start Yes Both No Com_slave_stop Yes Both No disconnect-slave-event-countYes Yes have_row_based_replication Yes Global No init_slave Yes Yes Yes Global Yes log-slave-updatesYes Yes Global No - _Variable_: Yes Global No log_slave_updates master-connect-retryYes Yes master-host Yes Yes master-info-fileYes Yes master-passwordYes Yes master-port Yes Yes master-retry-countYes Yes master-ssl Yes Yes master-ssl-ca Yes Yes master-ssl-capathYes Yes master-ssl-certYes Yes master-ssl-cipherYes Yes master-ssl-key Yes Yes master-user Yes Yes relay-log Yes Yes relay-log-indexYes Yes Both No - _Variable_: Yes Both No relay_log_index relay_log_indexYes Yes Yes Global No relay-log-info-fileYes Yes - _Variable_: relay_log_info_file relay_log_info_fileYes Yes Yes Global No relay_log_purgeYes Yes Yes Global Yes relay_log_space_limitYes Yes Yes Global No replicate-do-dbYes Yes replicate-do-tableYes Yes replicate-ignore-dbYes Yes replicate-ignore-tableYes Yes replicate-rewrite-dbYes Yes replicate-same-server-idYes Yes replicate-wild-do-tableYes Yes replicate-wild-ignore-tableYes Yes report-host Yes Yes Global No - _Variable_: Yes Global No report_host report-passwordYes Yes Global No - _Variable_: Yes Global No report_password report-port Yes Yes Global No - _Variable_: Yes Global No report_port report-user Yes Yes Global No - _Variable_: Yes Global No report_user rpl_recovery_rank Yes Global Yes Rpl_status Yes Global No show-slave-auth-infoYes Yes skip-slave-startYes Yes slave_compressed_protocolYes Yes Yes Global Yes slave_exec_mode Yes Global Yes Slave_heartbeat_period Yes Global No slave-load-tmpdirYes Yes Global No - _Variable_: Yes Global No slave_load_tmpdir slave-net-timeoutYes Yes Global Yes - _Variable_: Yes Global Yes slave_net_timeout Slave_open_temp_tables Yes Global No Slave_received_heartbeats Yes Global No Slave_retried_transactions Yes Global No Slave_running Yes Global No slave-skip-errorsYes Yes Global No - _Variable_: Yes Global No slave_skip_errors slave_transaction_retriesYes Yes Yes Global Yes slave_type_conversionsYes Yes Yes Global No sql_slave_skip_counter Yes Global Yes *Note replication-options-master::, provides more detailed information about options and variables relating to replication master servers. For more information about options and variables relating to replication slaves, see *Note replication-options-slave::. *Binary Logging Option/Variable Summary* Name Cmd-Line Option file System Var Status Var Var Scope Dynamic Binlog_cache_disk_use Yes Global No binlog_cache_sizeYes Yes Yes Global Yes Binlog_cache_use Yes Global No binlog_direct_non_transactional_updatesYes Yes Yes Both Yes binlog-do-db Yes Yes binlog-format Yes Yes Both Yes - _Variable_: Yes Both Yes binlog_format binlog-ignore-dbYes Yes binlog-row-event-max-sizeYes Yes Com_show_binlog_events Yes Both No Com_show_binlogs Yes Both No max_binlog_cache_sizeYes Yes Yes Global Yes max-binlog-dump-eventsYes Yes max_binlog_sizeYes Yes Yes Global Yes sporadic-binlog-dump-failYes Yes *Note replication-options-binary-log::, provides more detailed information about options and variables relating to binary logging. For additional general information about the binary log, see *Note binary-log::. For a table showing _all_ command-line options, system and status variables used with *Note `mysqld': mysqld, see *Note mysqld-option-tables::.  File: manual.info, Node: replication-options-master, Next: replication-options-slave, Prev: replication-options-table, Up: replication-options 16.1.3.2 Replication Master Options and Variables ................................................. This section describes the server options and system variables that you can use on replication master servers. You can specify the options either on the *Note command line: command-line-options. or in an *Note option file: option-files. You can specify system variable values using *Note `SET': set-option. On the master and each slave, you must use the `server-id' option to establish a unique replication ID. For each server, you should pick a unique positive integer in the range from 1 to 2^32 - 1, and each ID must be different from every other ID in use by any other replication master or slave. Example: `server-id=3'. For options used on the master for controlling binary logging, see *Note replication-options-binary-log::. * `auto_increment_increment' Options for auto_increment_increment *Command-Line `--auto_increment_increment[=#]' Format* *Option-File Format* `auto_increment_increment' *Option Sets Yes, Variable* `auto_increment_increment' *Variable Name* `auto_increment_increment' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `numeric' *Default* `1' *Range* `1-65535' `auto_increment_increment' and `auto_increment_offset' are intended for use with master-to-master replication, and can be used to control the operation of `AUTO_INCREMENT' columns. Both variables have global and session values, and each can assume an integer value between 1 and 65,535 inclusive. Setting the value of either of these two variables to 0 causes its value to be set to 1 instead. Attempting to set the value of either of these two variables to an integer greater than 65,535 or less than 0 causes its value to be set to 65,535 instead. Attempting to set the value of `auto_increment_increment' or `auto_increment_offset' to a noninteger value gives rise to an error, and the actual value of the variable remains unchanged. *Note*: `auto_increment_increment' is supported for use with *Note `NDB': mysql-cluster. tables beginning with MySQL 5.1.20, MySQL Cluster NDB 6.2.5, and MySQL Cluster NDB 6.3.2. Previously, setting it when using MySQL Cluster tables or MySQL Cluster Replication produced unpredictable results. These two variables affect `AUTO_INCREMENT' column behavior as follows: * `auto_increment_increment' controls the interval between successive column values. For example: mysql> SHOW VARIABLES LIKE 'auto_inc%'; +--------------------------+-------+ | Variable_name | Value | +--------------------------+-------+ | auto_increment_increment | 1 | | auto_increment_offset | 1 | +--------------------------+-------+ 2 rows in set (0.00 sec) mysql> CREATE TABLE autoinc1 -> (col INT NOT NULL AUTO_INCREMENT PRIMARY KEY); Query OK, 0 rows affected (0.04 sec) mysql> SET @@auto_increment_increment=10; Query OK, 0 rows affected (0.00 sec) mysql> SHOW VARIABLES LIKE 'auto_inc%'; +--------------------------+-------+ | Variable_name | Value | +--------------------------+-------+ | auto_increment_increment | 10 | | auto_increment_offset | 1 | +--------------------------+-------+ 2 rows in set (0.01 sec) mysql> INSERT INTO autoinc1 VALUES (NULL), (NULL), (NULL), (NULL); Query OK, 4 rows affected (0.00 sec) Records: 4 Duplicates: 0 Warnings: 0 mysql> SELECT col FROM autoinc1; +-----+ | col | +-----+ | 1 | | 11 | | 21 | | 31 | +-----+ 4 rows in set (0.00 sec) * `auto_increment_offset' determines the starting point for the `AUTO_INCREMENT' column value. Consider the following, assuming that these statements are executed during the same session as the example given in the description for `auto_increment_increment': mysql> SET @@auto_increment_offset=5; Query OK, 0 rows affected (0.00 sec) mysql> SHOW VARIABLES LIKE 'auto_inc%'; +--------------------------+-------+ | Variable_name | Value | +--------------------------+-------+ | auto_increment_increment | 10 | | auto_increment_offset | 5 | +--------------------------+-------+ 2 rows in set (0.00 sec) mysql> CREATE TABLE autoinc2 -> (col INT NOT NULL AUTO_INCREMENT PRIMARY KEY); Query OK, 0 rows affected (0.06 sec) mysql> INSERT INTO autoinc2 VALUES (NULL), (NULL), (NULL), (NULL); Query OK, 4 rows affected (0.00 sec) Records: 4 Duplicates: 0 Warnings: 0 mysql> SELECT col FROM autoinc2; +-----+ | col | +-----+ | 5 | | 15 | | 25 | | 35 | +-----+ 4 rows in set (0.02 sec) If the value of `auto_increment_offset' is greater than that of `auto_increment_increment', the value of `auto_increment_offset' is ignored. Should one or both of these variables be changed and then new rows inserted into a table containing an `AUTO_INCREMENT' column, the results may seem counterintuitive because the series of `AUTO_INCREMENT' values is calculated without regard to any values already present in the column, and the next value inserted is the least value in the series that is greater than the maximum existing value in the `AUTO_INCREMENT' column. In other words, the series is calculated like so: `auto_increment_offset' + N x `auto_increment_increment' where N is a positive integer value in the series [1, 2, 3, ...]. For example: mysql> SHOW VARIABLES LIKE 'auto_inc%'; +--------------------------+-------+ | Variable_name | Value | +--------------------------+-------+ | auto_increment_increment | 10 | | auto_increment_offset | 5 | +--------------------------+-------+ 2 rows in set (0.00 sec) mysql> SELECT col FROM autoinc1; +-----+ | col | +-----+ | 1 | | 11 | | 21 | | 31 | +-----+ 4 rows in set (0.00 sec) mysql> INSERT INTO autoinc1 VALUES (NULL), (NULL), (NULL), (NULL); Query OK, 4 rows affected (0.00 sec) Records: 4 Duplicates: 0 Warnings: 0 mysql> SELECT col FROM autoinc1; +-----+ | col | +-----+ | 1 | | 11 | | 21 | | 31 | | 35 | | 45 | | 55 | | 65 | +-----+ 8 rows in set (0.00 sec) The values shown for `auto_increment_increment' and `auto_increment_offset' generate the series 5 + N x 10, that is, [5, 15, 25, 35, 45, ...]. The greatest value present in the `col' column prior to the *Note `INSERT': insert. is 31, and the next available value in the `AUTO_INCREMENT' series is 35, so the inserted values for `col' begin at that point and the results are as shown for the *Note `SELECT': select. query. It is not possible to confine the effects of these two variables to a single table, and thus they do not take the place of the sequences offered by some other database management systems; these variables control the behavior of all `AUTO_INCREMENT' columns in _all_ tables on the MySQL server. If the global value of either variable is set, its effects persist until the global value is changed or overridden by setting the session value, or until *Note `mysqld': mysqld. is restarted. If the local value is set, the new value affects `AUTO_INCREMENT' columns for all tables into which new rows are inserted by the current user for the duration of the session, unless the values are changed during that session. The default value of `auto_increment_increment' is 1. See *Note replication-features-auto-increment::. * `auto_increment_offset' Options for auto_increment_offset *Command-Line `--auto_increment_offset[=#]' Format* *Option-File Format* `auto_increment_offset' *Option Sets Yes, Variable* `auto_increment_offset' *Variable Name* `auto_increment_offset' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `numeric' *Default* `1' *Range* `1-65535' This variable has a default value of 1. For particulars, see the description for `auto_increment_increment'. *Note*: `auto_increment_offset' is supported for use with *Note `NDB': mysql-cluster. tables beginning with MySQL 5.1.20, MySQL Cluster NDB 6.2.5, and MySQL Cluster NDB 6.3.2. Previously, setting it when using MySQL Cluster tables or MySQL Cluster Replication produced unpredictable results.  File: manual.info, Node: replication-options-slave, Next: replication-options-binary-log, Prev: replication-options-master, Up: replication-options 16.1.3.3 Replication Slave Options and Variables ................................................ This section describes the server options and system variables that apply to slave replication servers. You can specify the options either on the *Note command line: command-line-options. or in an *Note option file: option-files. Many of the options can be set while the server is running by using the *Note `CHANGE MASTER TO': change-master-to. statement. You can specify system variable values using *Note `SET': set-option. Server ID On the master and each slave, you must use the `server-id' option to establish a unique replication ID in the range from 1 to 2^32 - 1. `Unique' means that each ID must be different from every other ID in use by any other replication master or slave. Example `my.cnf' file: [mysqld] server-id=3 *Important*: Certain `--master-XXX' options are handled in a special way to ensure that the active replication configuration is not inadvertently altered or affected: * `--master-host' * `--master-user' * `--master-password' * `--master-port' * `--master-connect-retry' * `--master-ssl' * `--master-ssl-ca' * `--master-ssl-capath' * `--master-ssl-cert' * `--master-ssl-cipher' * `--master-ssl-key' Before MySQL 5.1.17, these options are silently ignored if given unless there is no `master.info' file. If that file exists, the MySQL server has already previously been configured for replication, so the information in the file is used instead. Because the server gives an existing `master.info' file precedence over the startup options just described, you might elect not to use startup options for these values at all, and instead to specify the replication parameters associated with them by using the *Note `CHANGE MASTER TO': change-master-to. statement. See *Note change-master-to::. Beginning with MySQL 5.1.17, these options are deprecated and have no effect when *Note `mysqld': mysqld. is started. If they are used, an appropriate warning is written to the error log. Instead, you _must_ use *Note `CHANGE MASTER TO': change-master-to. to set the values corresponding to the deprecated options. These options are removed in MySQL 5.5. The `master.info' file format in MySQL 5.1 includes as its first line the number of lines in the file. (See *Note slave-logs::.) If you upgrade an older server (before MySQL 4.1.1) to a newer version, the new server upgrades the `master.info' file to the new format automatically when it starts. However, if you downgrade a newer server to an older version, you should remove the first line manually before starting the older server for the first time. If no `master.info' file exists when the slave server starts, it uses the values for those options that are specified in option files or on the command line. This occurs when you start the server as a replication slave for the very first time, when you use *Note `CHANGE MASTER TO': change-master-to, or when you have run *Note `RESET SLAVE': reset-slave. and then have shut down and restarted the slave. Because the server uses `master.info' file contents and ignores any startup options that correspond to the values listed in the file, if you start the slave server with different values of the startup options that correspond to values in the file, the different values have no effect. To use different values, the preferred method is to use the *Note `CHANGE MASTER TO': change-master-to. statement to reset the values while the slave is running. Alternatively, you can stop the server, remove the `master.info' file, and restart the server with different option values. Suppose that you specify this option in your `my.cnf' file to configure a pre-5.1.17 slave server: [mysqld] master-host=SOME_HOST The first time you start the server as a replication slave, it reads and uses that option from the `my.cnf' file. The server then records the value in the `master.info' file. The next time you start the server, it reads the master host value from the `master.info' file only and ignores the value in the option file. If you modify the `my.cnf' file to specify a different master host value of SOME_OTHER_HOST, the change has no effect. Instead, use *Note `CHANGE MASTER TO': change-master-to. to change the value. This example shows a more extensive use of startup options to configure a pre-5.1.17 slave server: [mysqld] server-id=2 master-host=db-master.mycompany.com master-port=3306 master-user=pertinax master-password=freitag master-connect-retry=60 report-host=db-slave.mycompany.com As of 5.1.17, the `master-XXX' options are ignored and result in warnings in the error log. Startup options for replication slaves The following list describes startup options for controlling replication slave servers. Many of these options can be set while the server is running by using the *Note `CHANGE MASTER TO': change-master-to. statement. Others, such as the `--replicate-*' options, can be set only when the slave server starts. Replication-related system variables are discussed later in this section. * `--abort-slave-event-count' Options for abort-slave-event-count *Command-Line `--abort-slave-event-count=#' Format* *Option-File Format* `abort-slave-event-count' *Permitted Values * *Type* `numeric' *Default* `0' *Min Value* `0' When this option is set to some positive integer VALUE other than 0 (the default) it affects replication behavior as follows: After the slave SQL thread has started, VALUE log events are permitted to be executed; after that, the slave SQL thread does not receive any more events, just as if the network connection from the master were cut. The slave thread continues to run, and the output from *Note `SHOW SLAVE STATUS': show-slave-status. displays `Yes' in both the `Slave_IO_Running' and the `Slave_SQL_Running' columns, but no further events are read from the relay log. This option is used internally by the MySQL test suite for replication testing and debugging. It is not intended for use in a production setting. * `--disconnect-slave-event-count' Options for disconnect-slave-event-count *Command-Line `--disconnect-slave-event-count=#' Format* *Option-File Format* `disconnect-slave-event-count' *Permitted Values * *Type* `numeric' *Default* `0' This option is used internally by the MySQL test suite for replication testing and debugging. * `--log-slave-updates' Options for log-slave-updates *Command-Line `--log-slave-updates' Format* *Option-File Format* `log-slave-updates' *Option Sets Yes, Variable* `log_slave_updates' *Variable Name* `log_slave_updates' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `boolean' *Default* `FALSE' Normally, a slave does not log to its own binary log any updates that are received from a master server. This option tells the slave to log the updates performed by its SQL thread to its own binary log. For this option to have any effect, the slave must also be started with the `--log-bin' option to enable binary logging. `--log-slave-updates' is used when you want to chain replication servers. For example, you might want to set up replication servers using this arrangement: A -> B -> C Here, `A' serves as the master for the slave `B', and `B' serves as the master for the slave `C'. For this to work, `B' must be both a master _and_ a slave. You must start both `A' and `B' with `--log-bin' to enable binary logging, and `B' with the `--log-slave-updates' option so that updates received from `A' are logged by `B' to its binary log. When using MySQL Cluster Replication prior to MySQL Cluster NDB 6.2.16 and MySQL Cluster NDB 6.3.13, records for `empty' epochs--that is, epochs in which no changes to *Note `NDBCLUSTER': mysql-cluster. data or tables took place--were inserted into the `ndb_apply_status' and `ndb_binlog_index' tables on the slave even when `--log-slave-updates' was disabled (Bug#37472). Beginning with MySQL Cluster NDB 6.3.33, MySQL Cluster NDB 7.0.14, and MySQL Cluster NDB 7.1.3, it is possible to re-enable the older behavior by using the `--ndb-log-empty-epochs' option. *Note*: The `--ndb-log-empty-epochs' option was first implemented in MySQL Cluster NDB 6.3.21 and MySQL Cluster NDB 6.4.1, but did not work correctly before the versions cited previously. * `--log-slow-slave-statements' Options for log-slow-slave-statements *Version Introduced* 5.1.21 *Command-Line `--log-slow-slave-statements' Format* *Option-File Format* `log-slow-slave-statements' *Permitted Values * *Type* `boolean' *Default* `off' When the slow query log is enabled, this option enables logging for queries that have taken more than `long_query_time' seconds to execute on the slave. This option was added in MySQL 5.1.21. * `--log-warnings[=LEVEL]' Options for log-warnings *Command-Line `--log-warnings[=#]' Format* ** `-W [#]' *Option-File Format* `log-warnings' *Option Sets Yes, Variable* `log_warnings' *Variable Name* `log_warnings' *Variable Scope* Global, Session *Dynamic Variable* Yes *Disabled by* `skip-log-warnings' *Permitted Values * *Platform Bit Size* `64' *Type* `numeric' *Default* `1' *Range* `0-18446744073709547520' This option causes a server to print more messages to the error log about what it is doing. With respect to replication, the server generates warnings that it succeeded in reconnecting after a network/connection failure, and informs you as to how each slave thread started. This option is enabled by default; to disable it, use `--skip-log-warnings'. Aborted connections are not logged to the error log unless the value is greater than 1. Note that the effects of this option are not limited to replication. It produces warnings across a spectrum of server activities. * `--master-connect-retry=SECONDS' Options for master-connect-retry *Version Deprecated* 5.1.17 *Command-Line `--master-connect-retry=#' Format* *Option-File Format* `master-connect-retry' *Deprecated* 5.1.17 *Permitted Values * *Type* `numeric' *Default* `60' The number of seconds that the slave thread sleeps before trying to reconnect to the master in case the master goes down or the connection is lost. The value in the `master.info' file takes precedence if it can be read. If not set, the default is 60. Connection retries are not invoked until the slave times out reading data from the master according to the value of `--slave-net-timeout'. The number of reconnection attempts is limited by the `--master-retry-count' option. This option is deprecated as of MySQL 5.1.17 and is removed in MySQL 5.5. * `--master-host=HOST_NAME' Options for master-host *Version Deprecated* 5.1.17 *Command-Line `--master-host=name' Format* *Option-File Format* `master-host' *Deprecated* 5.1.17 *Permitted Values * *Type* `string' The host name or IP address of the master replication server. The value in `master.info' takes precedence if it can be read. If no master host is specified, the slave thread does not start. This option is deprecated as of MySQL 5.1.17 and is removed in MySQL 5.5. * `--master-info-file=FILE_NAME' Options for master-info-file *Command-Line `--master-info-file=file_name' Format* *Option-File Format* `master-info-file=file_name' *Permitted Values * *Type* `file name' *Default* `master.info' The name to use for the file in which the slave records information about the master. The default name is `master.info' in the data directory. For information about the format of this file, see *Note slave-logs-status::. * `--master-password=PASSWORD' Options for master-password *Version Deprecated* 5.1.17 *Command-Line `--master-password=name' Format* *Option-File Format* `master-password' *Deprecated* 5.1.17 *Permitted Values * *Type* `string' The password of the account that the slave thread uses for authentication when it connects to the master. The value in the `master.info' file takes precedence if it can be read. If not set, an empty password is assumed. This option is deprecated as of MySQL 5.1.17 and is removed in MySQL 5.5. * `--master-port=PORT_NUMBER' Options for master-port *Version Deprecated* 5.1.17 *Command-Line `--master-port=#' Format* *Option-File Format* `master-port' *Deprecated* 5.1.17 *Permitted Values * *Type* `numeric' *Default* `3306' The TCP/IP port number that the master is listening on. The value in the `master.info' file takes precedence if it can be read. If not set, the compiled-in setting is assumed (normally 3306). This option is deprecated as of MySQL 5.1.17 and is removed in MySQL 5.5. * `--master-retry-count=COUNT' Options for master-retry-count *Command-Line `--master-retry-count=#' Format* *Option-File Format* `master-retry-count' *Permitted Values * *Platform Bit Size* `32' *Type* `numeric' *Default* `86400' *Range* `0-4294967295' *Permitted Values * *Platform Bit Size* `64' *Type* `numeric' *Default* `86400' *Range* `0-18446744073709551615' The number of times that the slave tries to connect to the master before giving up. Reconnects are attempted at intervals set by the `--master-connect-retry' option (or the `MASTER_CONNECT_RETRY' option of the *Note `CHANGE MASTER TO': change-master-to. statement) and reconnects are triggered when data reads by the slave time out according to the `--slave-net-timeout' option. The default value is 86400. A value of 0 means `infinite'; the slave attempts to connect forever. * `--master-ssl', `--master-ssl-ca=FILE_NAME', `--master-ssl-capath=DIRECTORY_NAME', `--master-ssl-cert=FILE_NAME', `--master-ssl-cipher=CIPHER_LIST', `--master-ssl-key=FILE_NAME' These options are used for setting up a secure replication connection to the master server using SSL. Their meanings are the same as the corresponding `--ssl', `--ssl-ca', `--ssl-capath', `--ssl-cert', `--ssl-cipher', `--ssl-key' options that are described in *Note ssl-options::. The values in the `master.info' file take precedence if they can be read. These options are deprecated as of MySQL 5.1.17 and are removed in MySQL 5.5. * `--master-user=USER_NAME' Options for master-user *Version Deprecated* 5.1.17 *Command-Line `--master-user=name' Format* *Option-File Format* `master-user' *Deprecated* 5.1.17 *Permitted Values * *Type* `string' *Default* `test' The user name of the account that the slave thread uses for authentication when it connects to the master. This account must have the `REPLICATION SLAVE' privilege. The value in the `master.info' file takes precedence if it can be read. If the master user name is not set, the name `test' is assumed. This option is deprecated as of MySQL 5.1.17 and is removed in MySQL 5.5. * `--max-relay-log-size=SIZE' The size at which the server rotates relay log files automatically. For more information, see *Note slave-logs::. The default size is 1GB. * `--read-only' Cause the slave to permit no updates except from slave threads or from users having the `SUPER' privilege. On a slave server, this can be useful to ensure that the slave accepts updates only from its master server and not from clients. This variable does not apply to `TEMPORARY' tables. * `--relay-log=FILE_NAME' Options for relay-log *Command-Line `--relay-log=name' Format* *Option-File Format* `relay-log' *Permitted Values * *Type* `file name' The basename for the relay log. The default basename is `HOST_NAME-relay-bin'. The server writes the file in the data directory unless the basename is given with a leading absolute path name to specify a different directory. The server creates relay log files in sequence by adding a numeric suffix to the basename. Due to the manner in which MySQL parses server options, if you specify this option, you must supply a value; _the default basename is used only if the option is not actually specified_. If you use the `--relay-log' option without specifying a value, unexpected behavior is likely to result; this behavior depends on the other options used, the order in which they are specified, and whether they are specified on the command line or in an option file. For more information about how MySQL handles server options, see *Note program-options::. If you specify this option, the value specified is also used as the basename for the relay log index file. You can override this behavior by specifying a different relay log index file basename using the `--relay-log-index' option. You may find the `--relay-log' option useful in performing the following tasks: * Creating relay logs whose names are independent of host names. * If you need to put the relay logs in some area other than the data directory because your relay logs tend to be very large and you do not want to decrease `max_relay_log_size'. * To increase speed by using load-balancing between disks. * `--relay-log-index=FILE_NAME' Options for relay-log-index *Command-Line `--relay-log-index=name' Format* *Option-File Format* `relay-log-index' *Option Sets Yes, Variable* `relay_log_index' *Variable Name* `relay-log-index' *Variable Scope* Global, Session *Dynamic Variable* No *Permitted Values * *Type* `file name' The name to use for the relay log index file. The default name is `HOST_NAME-relay-bin.index' in the data directory, where HOST_NAME is the name of the slave server. Due to the manner in which MySQL parses server options, if you specify this option, you must supply a value; _the default basename is used only if the option is not actually specified_. If you use the `--relay-log-index' option without specifying a value, unexpected behavior is likely to result; this behavior depends on the other options used, the order in which they are specified, and whether they are specified on the command line or in an option file. For more information about how MySQL handles server options, see *Note program-options::. If you specify this option, the value specified is also used as the basename for the relay logs. You can override this behavior by specifying a different relay log file basename using the `--relay-log' option. * `--relay-log-info-file=FILE_NAME' Options for relay-log-info-file *Command-Line `--relay-log-info-file=file_name' Format* *Option-File Format* `relay-log-info-file' *Option Sets Yes, Variable* `relay_log_info_file' *Permitted Values * *Type* `file name' *Default* `relay-log.info' The name to use for the file in which the slave records information about the relay logs. The default name is `relay-log.info' in the data directory. For information about the format of this file, see *Note slave-logs-status::. * `--relay-log-purge={0|1}' Disable or enable automatic purging of relay logs as soon as they are no longer needed. The default value is 1 (enabled). This is a global variable that can be changed dynamically with `SET GLOBAL relay_log_purge = N'. * `--relay-log-space-limit=SIZE' This option places an upper limit on the total size in bytes of all relay logs on the slave. A value of 0 means `no limit.' This is useful for a slave server host that has limited disk space. When the limit is reached, the I/O thread stops reading binary log events from the master server until the SQL thread has caught up and deleted some unused relay logs. Note that this limit is not absolute: There are cases where the SQL thread needs more events before it can delete relay logs. In that case, the I/O thread exceeds the limit until it becomes possible for the SQL thread to delete some relay logs because not doing so would cause a deadlock. You should not set `--relay-log-space-limit' to less than twice the value of `--max-relay-log-size' (or `--max-binlog-size' if `--max-relay-log-size' is 0). In that case, there is a chance that the I/O thread waits for free space because `--relay-log-space-limit' is exceeded, but the SQL thread has no relay log to purge and is unable to satisfy the I/O thread. This forces the I/O thread to ignore `--relay-log-space-limit' temporarily. * `--replicate-do-db=DB_NAME' Options for replicate-do-db *Command-Line `--replicate-do-db=name' Format* *Option-File Format* `replicate-do-db' *Permitted Values * *Type* `string' The effects of this option depend on whether statement-based or row-based replication is in use. Statement-based replication Tell the slave SQL thread to restrict replication to statements where the default database (that is, the one selected by *Note `USE': use.) is DB_NAME. To specify more than one database, use this option multiple times, once for each database; however, doing so does _not_ replicate cross-database statements such as `UPDATE SOME_DB.SOME_TABLE SET foo='bar'' while a different database (or no database) is selected. *Warning*: To specify multiple databases you _must_ use multiple instances of this option. Because database names can contain commas, if you supply a comma separated list then the list will be treated as the name of a single database. An example of what does not work as you might expect when using statement-based replication: If the slave is started with `--replicate-do-db=sales' and you issue the following statements on the master, the *Note `UPDATE': update. statement is _not_ replicated: USE prices; UPDATE sales.january SET amount=amount+1000; The main reason for this `check just the default database' behavior is that it is difficult from the statement alone to know whether it should be replicated (for example, if you are using multiple-table *Note `DELETE': delete. statements or multiple-table *Note `UPDATE': update. statements that act across multiple databases). It is also faster to check only the default database rather than all databases if there is no need. Row-based replication Tells the slave SQL thread to restrict replication to database DB_NAME. Only tables belonging to DB_NAME are changed; the current database has no effect on this. Suppose that the slave is started with `--replicate-do-db=sales' and row-based replication is in effect, and then the following statements are run on the master: USE prices; UPDATE sales.february SET amount=amount+100; The `february' table in the `sales' database on the slave is changed in accordance with the *Note `UPDATE': update. statement; this occurs whether or not the *Note `USE': use. statement was issued. However, issuing the following statements on the master has no effect on the slave when using row-based replication and `--replicate-do-db=sales': USE prices; UPDATE prices.march SET amount=amount-25; Even if the statement `USE prices' were changed to `USE sales', the *Note `UPDATE': update. statement's effects would still not be replicated. Another important difference in how `--replicate-do-db' is handled in statement-based replication as opposed to row-based replication occurs with regard to statements that refer to multiple databases. Suppose that the slave is started with `--replicate-do-db=db1', and the following statements are executed on the master: USE db1; UPDATE db1.table1 SET col1 = 10, db2.table2 SET col2 = 20; If you are using statement-based replication, then both tables are updated on the slave. However, when using row-based replication, only `table1' is affected on the slave; since `table2' is in a different database, `table2' on the slave is not changed by the *Note `UPDATE': update. Now suppose that, instead of the `USE db1' statement, a `USE db4' statement had been used: USE db4; UPDATE db1.table1 SET col1 = 10, db2.table2 SET col2 = 20; In this case, the *Note `UPDATE': update. statement would have no effect on the slave when using statement-based replication. However, if you are using row-based replication, the *Note `UPDATE': update. would change `table1' on the slave, but not `table2'--in other words, only tables in the database named by `--replicate-do-db' are changed, and the choice of default database has no effect on this behavior. If you need cross-database updates to work, use `--replicate-wild-do-table=DB_NAME.%' instead. See *Note replication-rules::. *Note*: This option affects replication in the same manner that `--binlog-do-db' affects binary logging, and the effects of the replication format on how `--replicate-do-db' affects replication behavior are the same as those of the logging format on the behavior of `--binlog-do-db'. Beginning with MySQL 5.1.35, this option has no effect on *Note `BEGIN': commit, *Note `COMMIT': commit, or *Note `ROLLBACK': commit. statements. (Bug#43263) * `--replicate-ignore-db=DB_NAME' Options for replicate-ignore-db *Command-Line `--replicate-ignore-db=name' Format* *Option-File Format* `replicate-ignore-db' *Permitted Values * *Type* `string' As with `--replicate-do-db', the effects of this option depend on whether statement-based or row-based replication is in use. Statement-based replication Tells the slave SQL thread not to replicate any statement where the default database (that is, the one selected by *Note `USE': use.) is DB_NAME. Row-based replication Tells the slave SQL thread not to update any tables in the database DB_NAME. The default database has no effect. When using statement-based replication, the following example does not work as you might expect. Suppose that the slave is started with `--replicate-ignore-db=sales' and you issue the following statements on the master: USE prices; UPDATE sales.january SET amount=amount+1000; The *Note `UPDATE': update. statement _is_ replicated in such a case because `--replicate-ignore-db' applies only to the default database (determined by the *Note `USE': use. statement). Because the `sales' database was specified explicitly in the statement, the statement has not been filtered. However, when using row-based replication, the *Note `UPDATE': update. statement's effects are _not_ propagated to the slave, and the slave's copy of the `sales.january' table is unchanged; in this instance, `--replicate-ignore-db=sales' causes _all_ changes made to tables in the master's copy of the `sales' database to be ignored by the slave. To specify more than one database to ignore, use this option multiple times, once for each database. Because database names can contain commas, if you supply a comma separated list then the list will be treated as the name of a single database. You should not use this option if you are using cross-database updates and you do not want these updates to be replicated. See *Note replication-rules::. If you need cross-database updates to work, use `--replicate-wild-ignore-table=DB_NAME.%' instead. See *Note replication-rules::. *Note*: This option affects replication in the same manner that `--binlog-ignore-db' affects binary logging, and the effects of the replication format on how `--replicate-ignore-db' affects replication behavior are the same as those of the logging format on the behavior of `--binlog-ignore-db'. Beginning with MySQL 5.1.35, this option has no effect on *Note `BEGIN': commit, *Note `COMMIT': commit, or *Note `ROLLBACK': commit. statements. (Bug#43263) * `--replicate-do-table=DB_NAME.TBL_NAME' Options for replicate-do-table *Command-Line `--replicate-do-table=name' Format* *Option-File Format* `replicate-do-table' *Permitted Values * *Type* `string' Tells the slave SQL thread to restrict replication to the specified table. To specify more than one table, use this option multiple times, once for each table. This works for both cross-database updates and default database updates, in contrast to `--replicate-do-db'. See *Note replication-rules::. This option affects only statements that apply to tables. It does not affect statements that apply only to other database objects, such as stored routines. To filter statements operating on stored routines, use one or more of the `--replicate-*-db' options. * `--replicate-ignore-table=DB_NAME.TBL_NAME' Options for replicate-ignore-table *Command-Line `--replicate-ignore-table=name' Format* *Option-File Format* `replicate-ignore-table' *Permitted Values * *Type* `string' Tells the slave SQL thread not to replicate any statement that updates the specified table, even if any other tables might be updated by the same statement. To specify more than one table to ignore, use this option multiple times, once for each table. This works for cross-database updates, in contrast to `--replicate-ignore-db'. See *Note replication-rules::. This option affects only statements that apply to tables. It does not affect statements that apply only to other database objects, such as stored routines. To filter statements operating on stored routines, use one or more of the `--replicate-*-db' options. * `--replicate-rewrite-db=FROM_NAME->TO_NAME' Options for replicate-rewrite-db *Command-Line `--replicate-rewrite-db=old_name->new_name' Format* *Option-File Format* `replicate-rewrite-db' *Permitted Values * *Type* `string' Tells the slave to translate the default database (that is, the one selected by *Note `USE': use.) to TO_NAME if it was FROM_NAME on the master. Only statements involving tables are affected (not statements such as *Note `CREATE DATABASE': create-database, *Note `DROP DATABASE': drop-database, and *Note `ALTER DATABASE': alter-database.), and only if FROM_NAME is the default database on the master. This does not work for cross-database updates. To specify multiple rewrites, use this option multiple times. The server uses the first one with a FROM_NAME value that matches. The database name translation is done _before_ the `--replicate-*' rules are tested. If you use this option on the command line and the ``>'' character is special to your command interpreter, quote the option value. For example: shell> mysqld --replicate-rewrite-db="OLDDB->NEWDB" * `--replicate-same-server-id' Options for replicate-same-server-id *Command-Line `--replicate-same-server-id' Format* *Option-File Format* `replicate-same-server-id' *Permitted Values * *Type* `boolean' *Default* `FALSE' To be used on slave servers. Usually you should use the default setting of 0, to prevent infinite loops caused by circular replication. If set to 1, the slave does not skip events having its own server ID. Normally, this is useful only in rare configurations. Cannot be set to 1 if `--log-slave-updates' is used. By default, the slave I/O thread does not write binary log events to the relay log if they have the slave's server ID (this optimization helps save disk usage). If you want to use `--replicate-same-server-id', be sure to start the slave with this option before you make the slave read its own events that you want the slave SQL thread to execute. * `--replicate-wild-do-table=DB_NAME.TBL_NAME' Options for replicate-wild-do-table *Command-Line `--replicate-wild-do-table=name' Format* *Option-File Format* `replicate-wild-do-table' *Permitted Values * *Type* `string' Tells the slave thread to restrict replication to statements where any of the updated tables match the specified database and table name patterns. Patterns can contain the ``%'' and ``_'' wildcard characters, which have the same meaning as for the `LIKE' pattern-matching operator. To specify more than one table, use this option multiple times, once for each table. This works for cross-database updates. See *Note replication-rules::. This option applies to tables, views, and triggers. It does not apply to stored procedures and functions, or events. To filter statements operating on the latter objects, use one or more of the `--replicate-*-db' options. Example: `--replicate-wild-do-table=foo%.bar%' replicates only updates that use a table where the database name starts with `foo' and the table name starts with `bar'. If the table name pattern is `%', it matches any table name and the option also applies to database-level statements (*Note `CREATE DATABASE': create-database, *Note `DROP DATABASE': drop-database, and *Note `ALTER DATABASE': alter-database.). For example, if you use `--replicate-wild-do-table=foo%.%', database-level statements are replicated if the database name matches the pattern `foo%'. To include literal wildcard characters in the database or table name patterns, escape them with a backslash. For example, to replicate all tables of a database that is named `my_own%db', but not replicate tables from the `my1ownAABCdb' database, you should escape the ``_'' and ``%'' characters like this: `--replicate-wild-do-table=my\_own\%db'. If you use the option on the command line, you might need to double the backslashes or quote the option value, depending on your command interpreter. For example, with the `bash' shell, you would need to type `--replicate-wild-do-table=my\\_own\\%db'. * `--replicate-wild-ignore-table=DB_NAME.TBL_NAME' Options for replicate-wild-ignore-table *Command-Line `--replicate-wild-ignore-table=name' Format* *Option-File Format* `replicate-wild-ignore-table' *Permitted Values * *Type* `string' Tells the slave thread not to replicate a statement where any table matches the given wildcard pattern. To specify more than one table to ignore, use this option multiple times, once for each table. This works for cross-database updates. See *Note replication-rules::. Example: `--replicate-wild-ignore-table=foo%.bar%' does not replicate updates that use a table where the database name starts with `foo' and the table name starts with `bar'. For information about how matching works, see the description of the `--replicate-wild-do-table' option. The rules for including literal wildcard characters in the option value are the same as for `--replicate-wild-ignore-table' as well. * `--report-host=HOST_NAME' Options for report-host *Command-Line `--report-host=host_name' Format* *Option-File Format* `report-host' *Option Sets Yes, Variable* `report_host' *Variable Name* `report-host' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `string' The host name or IP address of the slave to be reported to the master during slave registration. This value appears in the output of *Note `SHOW SLAVE HOSTS': show-slave-hosts. on the master server. Leave the value unset if you do not want the slave to register itself with the master. Note that it is not sufficient for the master to simply read the IP address of the slave from the TCP/IP socket after the slave connects. Due to NAT and other routing issues, that IP may not be valid for connecting to the slave from the master or other hosts. * `--report-password=PASSWORD' Options for report-password *Command-Line `--report-password=name' Format* *Option-File Format* `report-password' *Option Sets Yes, Variable* `report_password' *Variable Name* `report-password' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `string' An arbitrary account password to be reported by the slave to the master during slave registration. This value appears in the output of *Note `SHOW SLAVE HOSTS': show-slave-hosts. on the master server if the `--show-slave-auth-info' option is given. Although the name of this option might imply otherwise, `--report-password' is not connected to the MySQL user privilege system and so is not necessarily (or even likely to be) the same as the password for the MySQL replication user account. * `--report-port=SLAVE_PORT_NUM' Options for report-port *Command-Line `--report-port=#' Format* *Option-File Format* `report-port' *Option Sets Yes, Variable* `report_port' *Variable Name* `report-port' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `numeric' *Default* `3306' The TCP/IP port number for connecting to the slave, to be reported to the master during slave registration. Set this only if the slave is listening on a nondefault port or if you have a special tunnel from the master or other clients to the slave. If you are not sure, do not use this option. * `--report-user=USER_NAME' Options for report-user *Command-Line `--report-user=name' Format* *Option-File Format* `report-user' *Option Sets Yes, Variable* `report_user' *Variable Name* `report-user' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `string' The account user name of the slave to be reported to the master during slave registration. This value appears in the output of *Note `SHOW SLAVE HOSTS': show-slave-hosts. on the master server if the `--show-slave-auth-info' option is given. Although the name of this option might imply otherwise, `--report-user' is not connected to the MySQL user privilege system and so is not necessarily (or even likely to be) the same as the name of the MySQL replication user account. * `--show-slave-auth-info' Options for show-slave-auth-info *Command-Line `--show-slave-auth-info' Format* *Option-File Format* `show-slave-auth-info' *Permitted Values * *Type* `boolean' *Default* `FALSE' Display slave user names and passwords in the output of *Note `SHOW SLAVE HOSTS': show-slave-hosts. on the master server for slaves started with the `--report-user' and `--report-password' options. * `--skip-slave-start' Options for skip-slave-start *Command-Line `--skip-slave-start' Format* *Option-File Format* `skip-slave-start' *Permitted Values * *Type* `boolean' *Default* `FALSE' Tells the slave server not to start the slave threads when the server starts. To start the threads later, use a *Note `START SLAVE': start-slave. statement. * `--slave_compressed_protocol={0|1}' Options for slave_compressed_protocol *Command-Line `--slave_compressed_protocol' Format* *Option-File Format* `slave_compressed_protocol' *Option Sets Yes, Variable* `slave_compressed_protocol' *Variable Name* `slave_compressed_protocol' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `boolean' *Default* `OFF' If this option is set to 1, use compression for the slave/master protocol if both the slave and the master support it. The default is 0 (no compression). * `--slave-load-tmpdir=FILE_NAME' The name of the directory where the slave creates temporary files. This option is by default equal to the value of the `tmpdir' system variable. When the slave SQL thread replicates a *Note `LOAD DATA INFILE': load-data. statement, it extracts the file to be loaded from the relay log into temporary files, and then loads these into the table. If the file loaded on the master is huge, the temporary files on the slave are huge, too. Therefore, it might be advisable to use this option to tell the slave to put temporary files in a directory located in some file system that has a lot of available space. In that case, the relay logs are huge as well, so you might also want to use the `--relay-log' option to place the relay logs in that file system. The directory specified by this option should be located in a disk-based file system (not a memory-based file system) because the temporary files used to replicate *Note `LOAD DATA INFILE': load-data. must survive machine restarts. The directory also should not be one that is cleared by the operating system during the system startup process. * `--slave-net-timeout=SECONDS' Options for slave-net-timeout *Command-Line `--slave-net-timeout=#' Format* *Option-File Format* `slave-net-timeout' *Option Sets Yes, Variable* `slave_net_timeout' *Variable Name* `slave_net_timeout' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `numeric' *Default* `3600' *Min Value* `1' The number of seconds to wait for more data from the master before the slave considers the connection broken, aborts the read, and tries to reconnect. The first retry occurs immediately after the timeout. The interval between retries is controlled by the `MASTER_CONNECT_RETRY' option for the *Note `CHANGE MASTER TO': change-master-to. statement or `--master-connect-retry' option, and the number of reconnection attempts is limited by the `--master-retry-count' option. The default is 3600 seconds (one hour). * `--slave-skip-errors=[ERR_CODE1,ERR_CODE2,...|all]' Options for slave-skip-errors *Command-Line `--slave-skip-errors=name' Format* *Option-File Format* `slave-skip-errors' *Option Sets Yes, Variable* `slave_skip_errors' *Variable Name* `slave_skip_errors' *Variable Scope* Global *Dynamic Variable* No Normally, replication stops when an error occurs on the slave. This gives you the opportunity to resolve the inconsistency in the data manually. This option tells the slave SQL thread to continue replication when a statement returns any of the errors listed in the option value. Do not use this option unless you fully understand why you are getting errors. If there are no bugs in your replication setup and client programs, and no bugs in MySQL itself, an error that stops replication should never occur. Indiscriminate use of this option results in slaves becoming hopelessly out of synchrony with the master, with you having no idea why this has occurred. *Note*: Prior to MySQL 5.1.35, this option had no effect with row-based logging. (Bug#39393) For error codes, you should use the numbers provided by the error message in your slave error log and in the output of *Note `SHOW SLAVE STATUS': show-slave-status. *Note error-handling::, lists server error codes. You can also (but should not) use the very nonrecommended value of `all' to cause the slave to ignore all error messages and keeps going regardless of what happens. Needless to say, if you use `all', there are no guarantees regarding the integrity of your data. Please do not complain (or file bug reports) in this case if the slave's data is not anywhere close to what it is on the master. _You have been warned_. Examples: --slave-skip-errors=1062,1053 --slave-skip-errors=all System variables used on replication slaves The following list describes system variables for controlling replication slave servers. They can be set at server startup and some of them can be changed at runtime using *Note `SET': set-option. Server options used with replication slaves are listed earlier in this section. * `init_slave' Options for init_slave *Command-Line `--init-slave=name' Format* *Option-File Format* `init_slave' *Option Sets Yes, Variable* `init_slave' *Variable Name* `init_slave' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `string' This variable is similar to `init_connect', but is a string to be executed by a slave server each time the SQL thread starts. The format of the string is the same as for the `init_connect' variable. *Note*: The SQL thread sends an acknowledgment to the client before it executes `init_slave'. Therefore, it is not guaranteed that `init_slave' has been executed when *Note `START SLAVE': start-slave. returns. See *Note start-slave::, for more information. * `relay_log_index' Options for relay_log_index *Command-Line `--relay-log-index' Format* *Option-File Format* `relay_log_index' *Option Sets Yes, Variable* `relay_log_index' *Variable Name* `relay_log_index' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `string' *Default* `*host_name*-relay-bin.index' The name of the relay log index file. The default name is `HOST_NAME-relay-bin.index' in the data directory, where HOST_NAME is the name of the slave server. * `relay_log_info_file' Options for relay_log_info_file *Command-Line `--relay-log-info-file=file_name' Format* *Option-File Format* `relay_log_info_file' *Option Sets Yes, Variable* `relay_log_info_file' *Variable Name* `relay_log_info_file' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `string' *Default* `relay-log.info' The name of the file in which the slave records information about the relay logs. The default name is `relay-log.info' in the data directory. * `rpl_recovery_rank' This variable is unused, and is removed in MySQL 5.6. * `slave_compressed_protocol' Options for slave_compressed_protocol *Command-Line `--slave_compressed_protocol' Format* *Option-File Format* `slave_compressed_protocol' *Option Sets Yes, Variable* `slave_compressed_protocol' *Variable Name* `slave_compressed_protocol' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `boolean' *Default* `OFF' Whether to use compression of the slave/master protocol if both the slave and the master support it. * `slave_exec_mode' Options for slave_exec_mode *Version Introduced* 5.1.23-ndb-6.2.14, 5.1.23-ndb-6.3.11, 5.1.24 *Variable Name* `slave_exec_mode' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `enumeration' *Default* `STRICT' (ALL) *Default* `IDEMPOTENT' (NDB) *Valid Values* `IDEMPOTENT' `STRICT' Controls whether `IDEMPOTENT' or `STRICT' mode is used in replication conflict resolution and error checking. `IDEMPOTENT' mode causes suppression of duplicate-key and no-key-found errors. Beginning with MySQL 5.1.23-ndb-6.2.14 and MySQL 5.1.24, this mode should be employed in multi-master replication, circular replication, and some other special replication scenarios. `STRICT' mode is the default, and is suitable for most other cases. *Note*: MySQL Cluster ignores any value explicitly set for `slave_exec_mode', and always treats it as `IDEMPOTENT'. * `slave_load_tmpdir' Options for slave-load-tmpdir *Command-Line `--slave-load-tmpdir=path' Format* *Option-File Format* `slave-load-tmpdir' *Option Sets Yes, Variable* `slave_load_tmpdir' *Variable Name* `slave_load_tmpdir' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `file name' *Default* `/tmp' The name of the directory where the slave creates temporary files for replicating *Note `LOAD DATA INFILE': load-data. statements. * `slave_net_timeout' Options for slave-net-timeout *Command-Line `--slave-net-timeout=#' Format* *Option-File Format* `slave-net-timeout' *Option Sets Yes, Variable* `slave_net_timeout' *Variable Name* `slave_net_timeout' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `numeric' *Default* `3600' *Min Value* `1' The number of seconds to wait for more data from a master/slave connection before aborting the read. This timeout applies only to TCP/IP connections, not to connections made using Unix socket files, named pipes, or shared memory. * `slave_skip_errors' Options for slave-skip-errors *Command-Line `--slave-skip-errors=name' Format* *Option-File Format* `slave-skip-errors' *Option Sets Yes, Variable* `slave_skip_errors' *Variable Name* `slave_skip_errors' *Variable Scope* Global *Dynamic Variable* No Normally, replication stops when an error occurs on the slave. This gives you the opportunity to resolve the inconsistency in the data manually. This variable tells the slave SQL thread to continue replication when a statement returns any of the errors listed in the variable value. * `slave_transaction_retries' Options for slave_transaction_retries *Command-Line `--slave_transaction_retries=#' Format* *Option-File Format* `slave_transaction_retries' *Option Sets Yes, Variable* `slave_transaction_retries' *Variable Name* `slave_transaction_retries' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Platform Bit Size* `32' *Type* `numeric' *Default* `10' *Range* `0-4294967295' *Permitted Values * *Platform Bit Size* `64' *Type* `numeric' *Default* `10' *Range* `0-18446744073709547520' If a replication slave SQL thread fails to execute a transaction because of an *Note `InnoDB': innodb-storage-engine. deadlock or because the transaction's execution time exceeded *Note `InnoDB': innodb-storage-engine.'s `innodb_lock_wait_timeout' or *Note `NDBCLUSTER': mysql-cluster.'s `TransactionDeadlockDetectionTimeout' or `TransactionInactiveTimeout', it automatically retries `slave_transaction_retries' times before stopping with an error. The default value is 10. * `slave_type_conversions' Options for slave_type_conversions *Version Introduced* 5.1.44-ndb-6.3.33, 5.1.44-ndb-7.0.14, 5.1.44-ndb-7.1.3 *Command-Line `--slave_type_conversions=set' Format* *Option-File Format* `slave_type_conversions' *Option Sets Yes, Variable* `slave_type_conversions' *Variable Name* `slave_type_conversions' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `set' *Default* `' *Valid Values* `ALL_LOSSY' `ALL_NON_LOSSY' `ALL_LOSSY,ALL_NON_LOSSY' Controls the type conversion mode in effect on the slave when using MySQL Cluster Replication. Its value is a comma-delimited set of zero or more elements from the list: `ALL_LOSSY', `ALL_NON_LOSSY'. Set this variable to an empty string to disallow type conversions between the master and the slave. Changes require a restart of the slave to take effect. For additional information on type conversion modes applicable to MySQL Cluster replication attribute promotion and demotion, see *Note replication-features-attribute-promotion::. This variable was added in MySQL Cluster NDB 6.3.33, 7.0.14, and 7.1.3. * `sql_slave_skip_counter' Options for sql_slave_skip_counter *Variable Name* `sql_slave_skip_counter' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `numeric' The number of events from the master that a slave server should skip. *Important*: If skipping the number of events specified by setting this variable would cause the slave to begin in the middle of an event group, the slave continues to skip until it finds the beginning of the next event group and begins from that point. For more information, see *Note set-global-sql-slave-skip-counter::.  File: manual.info, Node: replication-options-binary-log, Prev: replication-options-slave, Up: replication-options 16.1.3.4 Binary Log Options and Variables ......................................... You can use the *Note `mysqld': mysqld. options and system variables that are described in this section to affect the operation of the binary log as well as to control which statements are written to the binary log. For additional information about the binary log, see *Note binary-log::. For additional information about using MySQL server options and system variables, see *Note server-options::, and *Note server-system-variables::. Startup options used with binary logging The following list describes startup options for enabling and configuring the binary log. System variables used with binary logging are discussed later in this section. * `--binlog-row-event-max-size=N' Options for binlog-row-event-max-size *Version Introduced* 5.1.5 *Command-Line `--binlog-row-event-max-size=#' Format* *Option-File Format* `binlog-row-event-max-size' *Permitted Values * *Platform Bit Size* `32' *Type* `numeric' *Default* `1024' *Range* `256-4294967295' *Permitted Values * *Platform Bit Size* `64' *Type* `numeric' *Default* `1024' *Range* `256-18446744073709547520' Specify the maximum size of a row-based binary log event, in bytes. Rows are grouped into events smaller than this size if possible. The value should be a multiple of 256. The default is 1024. See *Note replication-formats::. This option was added in MySQL 5.1.5. * `--log-bin[=BASE_NAME]' Options for log-bin *Command-Line `--log-bin' Format* *Option-File Format* `log-bin' *Variable Name* `log_bin' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `file name' *Default* `OFF' Enable binary logging. The server logs all statements that change data to the binary log, which is used for backup and replication. See *Note binary-log::. The option value, if given, is the basename for the log sequence. The server creates binary log files in sequence by adding a numeric suffix to the basename. It is recommended that you specify a basename (see *Note bugs::, for the reason). Otherwise, MySQL uses `HOST_NAME-bin' as the basename. Setting this option causes the `log_bin' system variable to be set to `ON' (or `1'), and not to the basename. This is a known issue; see Bug#19614 for more information. * `--log-bin-index[=FILE_NAME]' Options for log-bin-index *Command-Line `--log-bin-index=name' Format* *Option-File Format* `log-bin-index' *Permitted Values * *Type* `file name' *Default* `OFF' The index file for binary log file names. See *Note binary-log::. If you omit the file name, and if you did not specify one with `--log-bin', MySQL uses `HOST_NAME-bin.index' as the file name. * `--log-bin-trust-function-creators[={0|1}]' Options for log-bin-trust-function-creators *Command-Line `--log-bin-trust-function-creators' Format* *Option-File Format* `log-bin-trust-function-creators' *Option Sets Yes, Variable* `log_bin_trust_function_creators' *Variable Name* `log_bin_trust_function_creators' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `boolean' *Default* `FALSE' This option sets the corresponding `log_bin_trust_function_creators' system variable. If no argument is given, the option sets the variable to 1. `log_bin_trust_function_creators' affects how MySQL enforces restrictions on stored function and trigger creation. See *Note stored-programs-logging::. *Note*: Previously, this option was known as `--log-bin-trust-routine-creators', which is now deprecated. Statement selection options The options in the following list affect which statements are written to the binary log, and thus sent by a replication master server to its slaves. There are also options for slave servers that control which statements received from the master should be executed or ignored. For details, see *Note replication-options-slave::. * `--binlog-do-db=DB_NAME' Options for binlog-do-db *Command-Line `--binlog-do-db=name' Format* *Option-File Format* `binlog-do-db' *Permitted Values * *Type* `string' This option affects binary logging in a manner similar to the way that `--replicate-do-db' affects replication. The effects of this option depend on whether the statement-based or row-based logging format is in use, in the same way that the effects of `--replicate-do-db' depend on whether statement-based or row-based replication is in use. You should keep in mind that the format used to log a given statement may not necessarily be the same as that indicated by the value of `binlog_format'. For example, DDL statements such as *Note `CREATE TABLE': create-table. and *Note `ALTER TABLE': alter-table. are always logged as statements, without regard to the logging format in effect, so the following statement-based rules for `--binlog-do-db' always apply in determining whether or not the statement is logged. Statement-based logging Only those statements are written to the binary log where the default database (that is, the one selected by *Note `USE': use.) is DB_NAME. To specify more than one database, use this option multiple times, once for each database; however, doing so does _not_ cause cross-database statements such as `UPDATE SOME_DB.SOME_TABLE SET foo='bar'' to be logged while a different database (or no database) is selected. *Warning*: To specify multiple databases you _must_ use multiple instances of this option. Because database names can contain commas, the list will be treated as the name of a single database if you supply a comma-separated list. An example of what does not work as you might expect when using statement-based logging: If the server is started with `--binlog-do-db=sales' and you issue the following statements, the *Note `UPDATE': update. statement is _not_ logged: USE prices; UPDATE sales.january SET amount=amount+1000; The main reason for this `just check the default database' behavior is that it is difficult from the statement alone to know whether it should be replicated (for example, if you are using multiple-table *Note `DELETE': delete. statements or multiple-table *Note `UPDATE': update. statements that act across multiple databases). It is also faster to check only the default database rather than all databases if there is no need. Another case which may not be self-evident occurs when a given database is replicated even though it was not specified when setting the option. If the server is started with `--binlog-do-db=sales', the following *Note `UPDATE': update. statement is logged even though `prices' was not included when setting `--binlog-do-db': USE sales; UPDATE prices.discounts SET percentage = percentage + 10; Because `sales' is the default database when the *Note `UPDATE': update. statement is issued, the *Note `UPDATE': update. is logged. Row-based logging Logging is restricted to database DB_NAME. Only changes to tables belonging to DB_NAME are logged; the default database has no effect on this. Suppose that the server is started with `--binlog-do-db=sales' and row-based logging is in effect, and then the following statements are executed: USE prices; UPDATE sales.february SET amount=amount+100; The changes to the `february' table in the `sales' database are logged in accordance with the *Note `UPDATE': update. statement; this occurs whether or not the *Note `USE': use. statement was issued. However, when using the row-based logging format and `--binlog-do-db=sales', changes made by the following *Note `UPDATE': update. are not logged: USE prices; UPDATE prices.march SET amount=amount-25; Even if the `USE prices' statement were changed to `USE sales', the *Note `UPDATE': update. statement's effects would still not be written to the binary log. Another important difference in `--binlog-do-db' handling for statement-based logging as opposed to the row-based logging occurs with regard to statements that refer to multiple databases. Suppose that the server is started with `--binlog-do-db=db1', and the following statements are executed: USE db1; UPDATE db1.table1 SET col1 = 10, db2.table2 SET col2 = 20; If you are using statement-based logging, the updates to both tables are written to the binary log. However, when using the row-based format, only the changes to `table1' are logged; `table2' is in a different database, so it is not changed by the *Note `UPDATE': update. Now suppose that, instead of the `USE db1' statement, a `USE db4' statement had been used: USE db4; UPDATE db1.table1 SET col1 = 10, db2.table2 SET col2 = 20; In this case, the *Note `UPDATE': update. statement is not written to the binary log when using statement-based logging. However, when using row-based logging, the change to `table1' is logged, but not that to `table2'--in other words, only changes to tables in the database named by `--binlog-do-db' are logged, and the choice of default database has no effect on this behavior. * `--binlog-ignore-db=DB_NAME' Options for binlog-ignore-db *Command-Line `--binlog-ignore-db=name' Format* *Option-File Format* `binlog-ignore-db' *Permitted Values * *Type* `string' This option affects binary logging in a manner similar to the way that `--replicate-ignore-db' affects replication. The effects of this option depend on whether the statement-based or row-based logging format is in use, in the same way that the effects of `--replicate-ignore-db' depend on whether statement-based or row-based replication is in use. You should keep in mind that the format used to log a given statement may not necessarily be the same as that indicated by the value of `binlog_format'. For example, DDL statements such as *Note `CREATE TABLE': create-table. and *Note `ALTER TABLE': alter-table. are always logged as statements, without regard to the logging format in effect, so the following statement-based rules for `--binlog-ignore-db' always apply in determining whether or not the statement is logged. Statement-based logging Tells the server to not log any statement where the default database (that is, the one selected by *Note `USE': use.) is DB_NAME. Row-based format Tells the server not to log updates to any tables in the database DB_NAME. The current database has no effect. When using statement-based logging, the following example does not work as you might expect. Suppose that the server is started with `--binlog-ignore-db=sales' and you issue the following statements: USE prices; UPDATE sales.january SET amount=amount+1000; The *Note `UPDATE': update. statement _is_ logged in such a case because `--binlog-ignore-db' applies only to the default database (determined by the *Note `USE': use. statement). Because the `sales' database was specified explicitly in the statement, the statement has not been filtered. However, when using row-based logging, the *Note `UPDATE': update. statement's effects are _not_ written to the binary log, which means that no changes to the `sales.january' table are logged; in this instance, `--binlog-ignore-db=sales' causes _all_ changes made to tables in the master's copy of the `sales' database to be ignored for purposes of binary logging. To specify more than one database to ignore, use this option multiple times, once for each database. Because database names can contain commas, the list will be treated as the name of a single database if you supply a comma-separated list. You should not use this option if you are using cross-database updates and you do not want these updates to be logged. Testing and debugging options The following binary log options are used in replication testing and debugging. They are not intended for use in normal operations. * `--max-binlog-dump-events=N' Options for max-binlog-dump-events *Command-Line `--max-binlog-dump-events=#' Format* *Option-File Format* `max-binlog-dump-events' *Permitted Values * *Type* `numeric' *Default* `0' This option is used internally by the MySQL test suite for replication testing and debugging. * `--sporadic-binlog-dump-fail' Options for sporadic-binlog-dump-fail *Command-Line `--sporadic-binlog-dump-fail' Format* *Option-File Format* `sporadic-binlog-dump-fail' *Permitted Values * *Type* `boolean' *Default* `FALSE' This option is used internally by the MySQL test suite for replication testing and debugging. System variables used with the binary log The following list describes system variables for controlling binary logging. They can be set at server startup and some of them can be changed at runtime using *Note `SET': set-option. Server options used to control binary logging are listed earlier in this section. * `binlog_cache_size' Options for binlog_cache_size *Command-Line `--binlog_cache_size=#' Format* *Option-File Format* `binlog_cache_size' *Option Sets Yes, Variable* `binlog_cache_size' *Variable Name* `binlog_cache_size' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Platform Bit Size* `32' *Type* `numeric' *Default* `32768' *Range* `4096-4294967295' *Permitted Values * *Platform Bit Size* `64' *Type* `numeric' *Default* `32768' *Range* `4096-18446744073709547520' The size of the cache to hold the SQL statements for the binary log during a transaction. A binary log cache is allocated for each client if the server supports any transactional storage engines and if the server has the binary log enabled (`--log-bin' option). If you often use large, multiple-statement transactions, you can increase this cache size to get better performance. The `Binlog_cache_use' and `Binlog_cache_disk_use' status variables can be useful for tuning the size of this variable. See *Note binary-log::. * `binlog_direct_non_transactional_updates' Options for binlog_direct_non_transactional_updates *Version Introduced* 5.1.44 *Command-Line `--binlog_direct_non_transactional_updates[=value]' Format* *Option-File Format* `binlog_direct_non_transactional_updates' *Option Sets Yes, Variable* `binlog_direct_non_transactional_updates' *Variable Name* `binlog_direct_non_transactional_updates' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `boolean' *Default* `OFF' Due to concurrency issues, a slave can become inconsistent when a transaction contains updates to both transactional and non-transactional tables. MySQL tries to preserve causality among these statements by writing non-transactional statements to the transaction cache, which is flushed upon commit. However, problems arise when modifications done to nontransactional tables on behalf of a transaction become immediately visible to other connections because these changes may not be written immediately into the binary log. Beginning with MySQL 5.1.44, the `binlog_direct_non_transactional_updates' variable offers one possible workaround to this issue. By default, this variable is disabled. Enabling `binlog_direct_non_transactional_updates' causes updates to nontransactional tables to be written directly to the binary log, rather than to the transaction cache. _`binlog_direct_non_transactional_updates' works only for statements that are replicated using the statement-based binary logging format_; that is, it works only when the value of `binlog_format' is `STATEMENT', or when `binlog_format' is `MIXED' and a given statement is being replicated using the statement-based format. This variable has no effect when the binary log format is `ROW', or when `binlog_format' is set to `MIXED' and a given statement is replicated using the row-based format. *Important*: Before enabling this variable, you must make certain that there are no dependencies between transactional and nontransactional tables; an example of such a dependency would be the statement `INSERT INTO myisam_table SELECT * FROM innodb_table'. Otherwise, such statements are likely to cause the slave to diverge from the master. * `binlog_format' Options for binlog-format *Version Introduced* 5.1.5 *Command-Line `--binlog-format=format' Format* *Option-File Format* `binlog-format=format' *Option Sets Yes, Variable* `binlog_format' *Variable Name* `binlog_format' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values (>= 5.1.5, <= 5.1.7)* *Type* `enumeration' *Default* `STATEMENT' *Valid Values* `ROW' `STATEMENT' *Permitted Values (>= 5.1.8, <= 5.1.11)* *Type* `enumeration' *Default* `STATEMENT' *Valid Values* `ROW' `STATEMENT' `MIXED' *Permitted Values (>= 5.1.12, <= 5.1.28)* *Type* `enumeration' *Default* `MIXED' *Valid Values* `ROW' `STATEMENT' `MIXED' *Permitted Values (>= 5.1.29)* *Type* `enumeration' *Default* `STATEMENT' *Valid Values* `ROW' `STATEMENT' `MIXED' This variable sets the binary logging format, and can be any one of `STATEMENT', `ROW', or `MIXED'. See *Note replication-formats::. `binlog_format' is set by the `--binlog-format' option at startup, or by the `binlog_format' variable at runtime. The startup variable was added in MySQL 5.1.5, and the runtime variable in MySQL 5.1.8. `MIXED' was added in MySQL 5.1.8. `STATEMENT' was used by default prior to MySQL 5.1.12; in MySQL 5.1.12, the default was changed to `MIXED'. In MySQL 5.1.29, the default was changed back to `STATEMENT'. You must have the `SUPER' privilege to set the global `binlog_format' value. Starting with MySQL 5.1.29, you must have the `SUPER' privilege to set either the global or session `binlog_format' value. (Bug#39106) The rules governing when changes to this variable take effect and how long the effect lasts are the same as for other MySQL server system variables. See *Note set-option::, for more information. When `MIXED' is specified, statement-based replication is used, except for cases where only row-based replication is guaranteed to lead to proper results. For example, this happens when statements contain user-defined functions (UDF) or the `UUID()' function. An exception to this rule is that `MIXED' always uses statement-based replication for stored functions and triggers. There are exceptions when you cannot switch the replication format at runtime: * From within a stored function or a trigger. * If the *Note `NDBCLUSTER': mysql-cluster. storage engine is enabled. * If the session is currently in row-based replication mode and has open temporary tables. Trying to switch the format in those cases results in an error. Before MySQL 5.1.8, switching to row-based replication format would implicitly set `--log-bin-trust-function-creators=1' and `--innodb_locks_unsafe_for_binlog'. This does not occur for MySQL 5.1.8 and later. The binary log format affects the behavior of the following server options: * `--replicate-do-db' * `--replicate-ignore-db' * `--binlog-do-db' * `--binlog-ignore-db' These effects are discussed in detail in the descriptions of the individual options. * `max_binlog_cache_size' Options for max_binlog_cache_size *Command-Line `--max_binlog_cache_size=#' Format* *Option-File Format* `max_binlog_cache_size' *Option Sets Yes, Variable* `max_binlog_cache_size' *Variable Name* `max_binlog_cache_size' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values (<= 5.1.35)* *Type* `numeric' *Default* `4294967295' *Range* `4096-4294967295' *Permitted Values (>= 5.1.36)* *Type* `numeric' *Default* `18446744073709547520' *Range* `4096-18446744073709547520' If a multiple-statement transaction requires more than this many bytes of memory, the server generates a `Multi-statement transaction required more than 'max_binlog_cache_size' bytes of storage' error. The minimum value is 4096. The maximum and default values are 4GB on 32-bit platforms and 16PB (petabytes) on 64-bit platforms. As of MySQL 5.1.36, the maximum value is 16PB on all platforms. In MySQL 5.1, a change in `max_binlog_cache_size' takes immediate effect for all active sessions. * `max_binlog_size' Options for max_binlog_size *Command-Line `--max_binlog_size=#' Format* *Option-File Format* `max_binlog_size' *Option Sets Yes, Variable* `max_binlog_size' *Variable Name* `max_binlog_size' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `numeric' *Default* `1073741824' *Range* `4096-1073741824' If a write to the binary log causes the current log file size to exceed the value of this variable, the server rotates the binary logs (closes the current file and opens the next one). The minimum value is 4096 bytes. The maximum and default value is 1GB. A transaction is written in one chunk to the binary log, so it is never split between several binary logs. Therefore, if you have big transactions, you might see binary log files larger than `max_binlog_size'. If `max_relay_log_size' is 0, the value of `max_binlog_size' applies to relay logs as well. * `sync_binlog' Options for sync_binlog *Command-Line `--sync-binlog=#' Format* *Option-File Format* `sync_binlog' *Option Sets Yes, Variable* `sync_binlog' *Variable Name* `sync_binlog' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Platform Bit Size* `32' *Type* `numeric' *Default* `0' *Range* `0-4294967295' *Permitted Values * *Platform Bit Size* `64' *Type* `numeric' *Default* `0' *Range* `0-18446744073709547520' If the value of this variable is greater than 0, the MySQL server synchronizes its binary log to disk (using `fdatasync()') after every `sync_binlog' writes to the binary log. There is one write to the binary log per statement if autocommit is enabled, and one write per transaction otherwise. The default value of `sync_binlog' is 0, which does no synchronizing to disk--in this case, the server relies on the operating system to flush the binary log's contents from to time as for any other file. A value of 1 is the safest choice because in the event of a crash you lose at most one statement or transaction from the binary log. However, it is also the slowest choice (unless the disk has a battery-backed cache, which makes synchronization very fast).  File: manual.info, Node: replication-administration, Prev: replication-options, Up: replication-configuration 16.1.4 Common Replication Administration Tasks ---------------------------------------------- * Menu: * replication-administration-status:: Checking Replication Status * replication-administration-pausing:: Pausing Replication on the Slave Once replication has been started it should execute without requiring much regular administration. Depending on your replication environment, you will want to check the replication status of each slave periodically, daily, or even more frequently.  File: manual.info, Node: replication-administration-status, Next: replication-administration-pausing, Prev: replication-administration, Up: replication-administration 16.1.4.1 Checking Replication Status .................................... The most common task when managing a replication process is to ensure that replication is taking place and that there have been no errors between the slave and the master. The primary statement for this is *Note `SHOW SLAVE STATUS': show-slave-status, which you must execute on each slave: mysql> SHOW SLAVE STATUS\G *************************** 1. row *************************** Slave_IO_State: Waiting for master to send event Master_Host: master1 Master_User: root Master_Port: 3306 Connect_Retry: 60 Master_Log_File: mysql-bin.000004 Read_Master_Log_Pos: 931 Relay_Log_File: slave1-relay-bin.000056 Relay_Log_Pos: 950 Relay_Master_Log_File: mysql-bin.000004 Slave_IO_Running: Yes Slave_SQL_Running: Yes Replicate_Do_DB: Replicate_Ignore_DB: Replicate_Do_Table: Replicate_Ignore_Table: Replicate_Wild_Do_Table: Replicate_Wild_Ignore_Table: Last_Errno: 0 Last_Error: Skip_Counter: 0 Exec_Master_Log_Pos: 931 Relay_Log_Space: 1365 Until_Condition: None Until_Log_File: Until_Log_Pos: 0 Master_SSL_Allowed: No Master_SSL_CA_File: Master_SSL_CA_Path: Master_SSL_Cert: Master_SSL_Cipher: Master_SSL_Key: Seconds_Behind_Master: 0 Master_SSL_Verify_Server_Cert: No Last_IO_Errno: 0 Last_IO_Error: Last_SQL_Errno: 0 Last_SQL_Error: The key fields from the status report to examine are: * `Slave_IO_State': The current status of the slave. See *Note slave-io-thread-states::, and *Note slave-sql-thread-states::, for more information. * `Slave_IO_Running': Whether the I/O thread for reading the master's binary log is running. Normally, you want this to be `Yes' unless you have not yet started replication or have explicitly stopped it with *Note `STOP SLAVE': stop-slave. * `Slave_SQL_Running': Whether the SQL thread for executing events in the relay log is running. As with the I/O thread, this should normally be `Yes'. * `Last_IO_Error', `Last_SQL_Error': The last errors registered by the I/O and SQL threads when processing the relay log. Ideally these should be blank, indicating no errors. * `Seconds_Behind_Master': The number of seconds that the slave SQL thread is behind processing the master binary log. A high number (or an increasing one) can indicate that the slave is unable to handle events from the master in a timely fashion. A value of 0 for `Seconds_Behind_Master' can usually be interpreted as meaning that the slave has caught up with the master, but there are some cases where this is not strictly true. For example, this can occur if the network connection between master and slave is broken but the slave I/O thread has not yet noticed this--that is, `slave_net_timeout' has not yet elapsed. It is also possible that transient values for `Seconds_Behind_Master' may not reflect the situation accurately. When the slave SQL thread has caught up on I/O, `Seconds_Behind_Master' displays 0; but when the slave I/O thread is still queuing up a new event, `Seconds_Behind_Master' may show a large value until the SQL thread finishes executing the new event. This is especially likely when the events have old timestamps; in such cases, if you execute *Note `SHOW SLAVE STATUS': show-slave-status. several times in a relatively short period, you may see this value change back and forth repeatedly between 0 and a relatively large value. Several pairs of fields provide information about the progress of the slave in reading events from the master binary log and processing them in the relay log: * (`Master_Log_file', `Read_Master_Log_Pos'): Coordinates in the master binary log indicating how far the slave I/O thread has read events from that log. * (`Relay_Master_Log_File', `Exec_Master_Log_Pos'): Coordinates in the master binary log indicating how far the slave SQL thread has executed events received from that log. * (`Relay_Log_File', `Relay_Log_Pos'): Coordinates in the slave relay log indicating how far the slave SQL thread has executed the relay log. These correspond to the preceding coordinates, but are expressed in slave relay log coordinates rather than master binary log coordinates. On the master, you can check the status of connected slaves using *Note `SHOW PROCESSLIST': show-processlist. to examine the list of running processes. Slave connections have `Binlog Dump' in the `Command' field: mysql> SHOW PROCESSLIST \G; *************************** 4. row *************************** Id: 10 User: root Host: slave1:58371 db: NULL Command: Binlog Dump Time: 777 State: Has sent all binlog to slave; waiting for binlog to be updated Info: NULL Because it is the slave that drives the replication process, very little information is available in this report. For slaves that were started with the `--report-host' option and are connected to the master, the *Note `SHOW SLAVE HOSTS': show-slave-hosts. statement on the master shows basic information about the slaves. The output includes the ID of the slave server, the value of the `--report-host' option, the connecting port, and master ID: mysql> SHOW SLAVE HOSTS; +-----------+--------+------+-------------------+-----------+ | Server_id | Host | Port | Rpl_recovery_rank | Master_id | +-----------+--------+------+-------------------+-----------+ | 10 | slave1 | 3306 | 0 | 1 | +-----------+--------+------+-------------------+-----------+ 1 row in set (0.00 sec)  File: manual.info, Node: replication-administration-pausing, Prev: replication-administration-status, Up: replication-administration 16.1.4.2 Pausing Replication on the Slave ......................................... You can stop and start the replication of statements on the slave using the *Note `STOP SLAVE': stop-slave. and *Note `START SLAVE': start-slave. statements. To stop processing of the binary log from the master, use *Note `STOP SLAVE': stop-slave.: mysql> STOP SLAVE; When replication is stopped, the slave I/O thread stops reading events from the master binary log and writing them to the relay log, and the SQL thread stops reading events from the relay log and executing them. You can pause the I/O or SQL thread individually by specifying the thread type: mysql> STOP SLAVE IO_THREAD; mysql> STOP SLAVE SQL_THREAD; To start execution again, use the *Note `START SLAVE': start-slave. statement: mysql> START SLAVE; To start a particular thread, specify the thread type: mysql> START SLAVE IO_THREAD; mysql> START SLAVE SQL_THREAD; For a slave that performs updates only by processing events from the master, stopping only the SQL thread can be useful if you want to perform a backup or other task. The I/O thread will continue to read events from the master but they are not executed. This makes it easier for the slave to catch up when you restart the SQL thread. Stopping only the I/O thread enables the events in the relay log to be executed by the SQL thread up to the point where the relay log ends. This can be useful when you want to pause execution to catch up with events already received from the master, when you want to perform administration on the slave but also ensure that it has processed all updates to a specific point. This method can also be used to pause event receipt on the slave while you conduct administration on the master. Stopping the I/O thread but permitting the SQL thread to run helps ensure that there is not a massive backlog of events to be executed when replication is started again.  File: manual.info, Node: replication-implementation, Next: replication-solutions, Prev: replication-configuration, Up: replication 16.2 Replication Implementation =============================== * Menu: * replication-implementation-details:: Replication Implementation Details * slave-logs:: Replication Relay and Status Logs * replication-rules:: How Servers Evaluate Replication Filtering Rules Replication is based on the master server keeping track of all changes to its databases (updates, deletes, and so on) in its binary log. The binary log serves as a written record of all events that modify database structure or content (data) from the moment the server was started. Typically, *Note `SELECT': select. statements are not recorded because they modify neither database structure nor content. Each slave that connects to the master requests a copy of the binary log. That is, it pulls the data from the master, rather than the master pushing the data to the slave. The slave also executes the events from the binary log that it receives. This has the effect of repeating the original changes just as they were made on the master. Tables are created or their structure modified, and data is inserted, deleted, and updated according to the changes that were originally made on the master. Because each slave is independent, the replaying of the changes from the master's binary log occurs independently on each slave that is connected to the master. In addition, because each slave receives a copy of the binary log only by requesting it from the master, the slave is able to read and update the copy of the database at its own pace and can start and stop the replication process at will without affecting the ability to update to the latest database status on either the master or slave side. For more information on the specifics of the replication implementation, see *Note replication-implementation-details::. Masters and slaves report their status in respect of the replication process regularly so that you can monitor them. See *Note thread-information::, for descriptions of all replicated-related states. The master binary log is written to a local relay log on the slave before it is processed. The slave also records information about the current position with the master's binary log and the local relay log. See *Note slave-logs::. Database changes are filtered on the slave according to a set of rules that are applied according to the various configuration options and variables that control event evaluation. For details on how these rules are applied, see *Note replication-rules::.  File: manual.info, Node: replication-implementation-details, Next: slave-logs, Prev: replication-implementation, Up: replication-implementation 16.2.1 Replication Implementation Details ----------------------------------------- MySQL replication capabilities are implemented using three threads, one on the master server and two on the slave: * Binlog dump thread The master creates a thread to send the binary log contents to a slave when the slave connects. This thread can be identified in the output of *Note `SHOW PROCESSLIST': show-processlist. on the master as the `Binlog Dump' thread. The binlog dump thread acquires a lock on the master's binary log for reading each event that is to be sent to the slave. As soon as the event has been read, the lock is released, even before the event is sent to the slave. * Slave I/O thread When a *Note `START SLAVE': start-slave. statement is issued on a slave server, the slave creates an I/O thread, which connects to the master and asks it to send the updates recorded in its binary logs. The slave I/O thread reads the updates that the master's `Binlog Dump' thread sends (see previous item) and copies them to local files that comprise the slave's relay log. The state of this thread is shown as `Slave_IO_running' in the output of *Note `SHOW SLAVE STATUS': show-slave-status. or as `Slave_running' in the output of *Note `SHOW STATUS': show-status. * Slave SQL thread The slave creates an SQL thread to read the relay log that is written by the slave I/O thread and execute the events contained therein. In the preceding description, there are three threads per master/slave connection. A master that has multiple slaves creates one binlog dump thread for each currently connected slave, and each slave has its own I/O and SQL threads. A slave uses two threads to separate reading updates from the master and executing them into independent tasks. Thus, the task of reading statements is not slowed down if statement execution is slow. For example, if the slave server has not been running for a while, its I/O thread can quickly fetch all the binary log contents from the master when the slave starts, even if the SQL thread lags far behind. If the slave stops before the SQL thread has executed all the fetched statements, the I/O thread has at least fetched everything so that a safe copy of the statements is stored locally in the slave's relay logs, ready for execution the next time that the slave starts. This enables the master server to purge its binary logs sooner because it no longer needs to wait for the slave to fetch their contents. The *Note `SHOW PROCESSLIST': show-processlist. statement provides information that tells you what is happening on the master and on the slave regarding replication. For information on master states, see *Note master-thread-states::. For slave states, see *Note slave-io-thread-states::, and *Note slave-sql-thread-states::. The following example illustrates how the three threads show up in the output from *Note `SHOW PROCESSLIST': show-processlist. On the master server, the output from *Note `SHOW PROCESSLIST': show-processlist. looks like this: mysql> SHOW PROCESSLIST\G *************************** 1. row *************************** Id: 2 User: root Host: localhost:32931 db: NULL Command: Binlog Dump Time: 94 State: Has sent all binlog to slave; waiting for binlog to be updated Info: NULL Here, thread 2 is a `Binlog Dump' replication thread that services a connected slave. The `State' information indicates that all outstanding updates have been sent to the slave and that the master is waiting for more updates to occur. If you see no `Binlog Dump' threads on a master server, this means that replication is not running; that is, no slaves are currently connected. On a slave server, the output from *Note `SHOW PROCESSLIST': show-processlist. looks like this: mysql> SHOW PROCESSLIST\G *************************** 1. row *************************** Id: 10 User: system user Host: db: NULL Command: Connect Time: 11 State: Waiting for master to send event Info: NULL *************************** 2. row *************************** Id: 11 User: system user Host: db: NULL Command: Connect Time: 11 State: Has read all relay log; waiting for the slave I/O thread to update it Info: NULL The `State' information indicates that thread 10 is the I/O thread that is communicating with the master server, and thread 11 is the SQL thread that is processing the updates stored in the relay logs. At the time that *Note `SHOW PROCESSLIST': show-processlist. was run, both threads were idle, waiting for further updates. The value in the `Time' column can show how late the slave is compared to the master. See *Note replication-faq::. If sufficient time elapses on the master side without activity on the `Binlog Dump' thread, the master determines that the slave is no longer connected. As for any other client connection, the timeouts for this depend on the values of `net_write_timeout' and `net_retry_count'; for more information about these, see *Note server-system-variables::. The *Note `SHOW SLAVE STATUS': show-slave-status. statement provides additional information about replication processing on a slave server. See *Note replication-administration-status::.  File: manual.info, Node: slave-logs, Next: replication-rules, Prev: replication-implementation-details, Up: replication-implementation 16.2.2 Replication Relay and Status Logs ---------------------------------------- * Menu: * slave-logs-relaylog:: The Slave Relay Log * slave-logs-status:: Slave Status Logs During replication, a slave server creates several logs that hold the binary log events relayed from the master to the slave, and to record information about the current status and location within the relay log. There are three types of logs used in the process, listed here: * The _relay log_ consists of the events read from the binary log of the master and written by the slave I/O thread. Events in the relay log are executed on the slave as part of the SQL thread. * The _master info log_ contains status and current configuration information for the slave's connection to the master. This log holds information on the master host name, login credentials, and coordinates indicating how far the slave has read from the master's binary log. * The _relay log info log_ holds status information about the execution point within the slave's relay log.  File: manual.info, Node: slave-logs-relaylog, Next: slave-logs-status, Prev: slave-logs, Up: slave-logs 16.2.2.1 The Slave Relay Log ............................ The relay log, like the binary log, consists of a set of numbered files containing events that describe database changes, and an index file that contains the names of all used relay log files. The term `relay log file' generally denotes an individual numbered file containing database events. The term `relay log' collectively denotes the set of numbered relay log files plus the index file. Relay log files have the same format as binary log files and can be read using *Note `mysqlbinlog': mysqlbinlog. (see *Note mysqlbinlog::). By default, relay log file names have the form `HOST_NAME-relay-bin.NNNNNN' in the data directory, where HOST_NAME is the name of the slave server host and NNNNNN is a sequence number. Successive relay log files are created using successive sequence numbers, beginning with `000001'. The slave uses an index file to track the relay log files currently in use. The default relay log index file name is `HOST_NAME-relay-bin.index' in the data directory. The default relay log file and relay log index file names can be overridden with, respectively, the `--relay-log' and `--relay-log-index' server options (see *Note replication-options::). If a slave uses the default host-based relay log file names, changing a slave's host name after replication has been set up can cause replication to fail with the errors `Failed to open the relay log' and `Could not find target log during relay log initialization'. This is a known issue (see Bug#2122). If you anticipate that a slave's host name might change in the future (for example, if networking is set up on the slave such that its host name can be modified using DHCP), you can avoid this issue entirely by using the `--relay-log' and `--relay-log-index' options to specify relay log file names explicitly when you initially set up the slave. This will make the names independent of server host name changes. If you encounter the issue after replication has already begun, one way to work around it is to stop the slave server, prepend the contents of the old relay log index file to the new one, and then restart the slave. On a Unix system, this can be done as shown here: shell> cat NEW_RELAY_LOG_NAME.index >> OLD_RELAY_LOG_NAME.index shell> mv OLD_RELAY_LOG_NAME.index NEW_RELAY_LOG_NAME.index A slave server creates a new relay log file under the following conditions: * Each time the I/O thread starts. * When the logs are flushed; for example, with *Note `FLUSH LOGS': flush. or *Note `mysqladmin flush-logs': mysqladmin. * When the size of the current relay log file becomes `too large,' determined as follows: * If the value of `max_relay_log_size' is greater than 0, that is the maximum relay log file size. * If the value of `max_relay_log_size' is 0, `max_binlog_size' determines the maximum relay log file size. The SQL thread automatically deletes each relay log file as soon as it has executed all events in the file and no longer needs it. There is no explicit mechanism for deleting relay logs because the SQL thread takes care of doing so. However, *Note `FLUSH LOGS': flush. rotates relay logs, which influences when the SQL thread deletes them.  File: manual.info, Node: slave-logs-status, Prev: slave-logs-relaylog, Up: slave-logs 16.2.2.2 Slave Status Logs .......................... A replication slave server creates two logs. By default, these logs are files named `master.info' and `relay-log.info' and created in the data directory. The names and locations of these files can be changed by using the `--master-info-file' and `--relay-log-info-file' options, respectively. See *Note replication-options::. The two status logs contain information like that shown in the output of the *Note `SHOW SLAVE STATUS': show-slave-status. statement, which is discussed in *Note replication-slave-sql::. Because the status logs are stored on disk, they survive a slave server's shutdown. The next time the slave starts up, it reads the two logs to determine how far it has proceeded in reading binary logs from the master and in processing its own relay logs. The master info log should be protected because it contains the password for connecting to the master. See *Note password-security-admin::. The slave I/O thread updates the master info log. The following table shows the correspondence between the lines in the `master.info' file and the columns displayed by *Note `SHOW SLAVE STATUS': show-slave-status. Line in `SHOW SLAVE STATUS' Description `master.info'Column 1 Number of lines in the file 2 `Master_Log_File' The name of the master binary log currently being read from the master 3 `Read_Master_Log_Pos' The current position within the master binary log that have been read from the master 4 `Master_Host' The host name of the master 5 `Master_User' The user name used to connect to the master 6 Password (not shown by The password used to connect to the *Note `SHOW SLAVE master STATUS': show-slave-status.) 7 `Master_Port' The network port used to connect to the master 8 `Connect_Retry' The period (in seconds) that the slave will wait before trying to reconnect to the master 9 `Master_SSL_Allowed' Indicates whether the server supports SSL connections 10 `Master_SSL_CA_File' The file used for the Certificate Authority (CA) certificate 11 `Master_SSL_CA_Path' The path to the Certificate Authority (CA) certificates 12 `Master_SSL_Cert' The name of the SSL certificate file 13 `Master_SSL_Cipher' The list of possible ciphers used in the handshake for the SSL connection 14 `Master_SSL_Key' The name of the SSL key file 15 `Master_SSL_Verify_Server_Cert'Whether to verify the server certificate (added in MySQL 5.1.18) The slave SQL thread updates the relay log info log. The following table shows the correspondence between the lines in the `relay-log.info' file and the columns displayed by *Note `SHOW SLAVE STATUS': show-slave-status. Line in `SHOW SLAVE STATUS' Description `relay-log.info'Column 1 `Relay_Log_File' The name of the current relay log file 2 `Relay_Log_Pos' The current position within the relay log file; events up to this position have been executed on the slave database 3 `Relay_Master_Log_File' The name of the master binary log file from which the events in the relay log file were read 4 `Exec_Master_Log_Pos' The equivalent position within the master's binary log file of events that have already been executed The contents of the `relay-log.info' file and the states shown by the *Note `SHOW SLAVE STATUS': show-slave-status. statement might not match if the `relay-log.info' file has not been flushed to disk. Ideally, you should only view `relay-log.info' on a slave that is offline (that is, `mysqld' is not running). For a running system, *Note `SHOW SLAVE STATUS': show-slave-status. should be used. When you back up the slave's data, you should back up these two status logs, along with the relay log files. The status logs are needed to resume replication after you restore the data from the slave. If you lose the relay logs but still have the relay log info log, you can check it to determine how far the SQL thread has executed in the master binary logs. Then you can use *Note `CHANGE MASTER TO': change-master-to. with the `MASTER_LOG_FILE' and `MASTER_LOG_POS' options to tell the slave to re-read the binary logs from that point. Of course, this requires that the binary logs still exist on the master.  File: manual.info, Node: replication-rules, Prev: slave-logs, Up: replication-implementation 16.2.3 How Servers Evaluate Replication Filtering Rules ------------------------------------------------------- * Menu: * replication-rules-db-options:: Evaluation of Database-Level Replication and Binary Logging Options * replication-rules-table-options:: Evaluation of Table-Level Replication Options * replication-rules-examples:: Replication Rule Application If a master server does not write a statement to its binary log, the statement is not replicated. If the server does log the statement, the statement is sent to all slaves and each slave determines whether to execute it or ignore it. On the master, you can control which databases to log changes for by using the `--binlog-do-db' and `--binlog-ignore-db' options to control binary logging. For a description of the rules that servers use in evaluating these options, see *Note replication-rules-db-options::. You should not use these options to control which databases and tables are replicated. Instead, use filtering on the slave to control the events that are executed on the slave. On the slave side, decisions about whether to execute or ignore statements received from the master are made according to the `--replicate-*' options that the slave was started with. (See *Note replication-options::.) In the simplest case, when there are no `--replicate-*' options, the slave executes all statements that it receives from the master. Otherwise, the result depends on the particular options given. Database-level options (`--replicate-do-db', `--replicate-ignore-db') are checked first; see *Note replication-rules-db-options::, for a description of this process. If no matching database-level options are found, option checking proceeds to any table-level options that may be in use, as discussed in *Note replication-rules-table-options::. To make it easier to determine what effect an option set will have, it is recommended that you avoid mixing `do' and `ignore' options, or wildcard and nonwildcard options. An example of the latter that may have unintended effects is the use of `--replicate-do-db' and `--replicate-wild-do-table' together, where `--replicate-wild-do-table' uses a pattern for the database name that matches the name given for `--replicate-do-db'. Suppose a replication slave is started with `--replicate-do-db=dbx' `--replicate-wild-do-table=db%.t1'. Then, suppose that on the master, you issue the statement *Note `CREATE DATABASE dbx': create-database. Although you might expect it, this statement is not replicated because it does not reference a table named `t1'. If any `--replicate-rewrite-db' options were specified, they are applied before the `--replicate-*' filtering rules are tested. *Note*: In MySQL 5.1, database-level filtering options are case-sensitive on platforms supporting case sensitivity in filenames, whereas table-level filtering options are not (regardless of platform). This is true regardless of the value of the `lower_case_table_names' system variable. These are known issues which are fixed in MySQL 5.5.  File: manual.info, Node: replication-rules-db-options, Next: replication-rules-table-options, Prev: replication-rules, Up: replication-rules 16.2.3.1 Evaluation of Database-Level Replication and Binary Logging Options ............................................................................ When evaluating replication options, the slave begins by checking to see whether there are any `--replicate-do-db' or `--replicate-ignore-db' options that apply. When using `--binlog-do-db' or `--binlog-ignore-db', the process is similar, but the options are checked on the master. With statement-based replication, the default database is checked for a match. With row-based replication, the database where data is to be changed is the database that is checked. Regardless of the binary logging format, checking of database-level options proceeds as shown in the following diagram. Evaluation of Database-Level Filtering Rules in Replication The steps involved are listed here: 1. Are there any `--replicate-do-db' options? * Yes Do any of them match the database? * Yes Execute the statement and exit. * No Continue to step 2. * No Continue to step 2. 2. Are there any `--replicate-ignore-db' options? * Yes Do any of them match the database? * Yes Ignore the statement and exit. * No Continue to step 3. * No Continue to step 3. 3. Proceed to checking the table-level replication options, if there are any. For a description of how these options are checked, see *Note replication-rules-table-options::. *Important*: A statement that is still permitted at this stage is not yet actually executed. The statement is not executed until all table-level options (if any) have also been checked, and the outcome of that process permits execution of the statement. For binary logging, the steps involved are listed here: 1. Are there any `--binlog-do-db' or `--binlog-ignore-db' options? * Yes Continue to step 2. * No Log the statement and exit. 2. Is there a default database (has any database been selected by *Note `USE': use.)? * Yes Continue to step 3. * No Ignore the statement and exit. 3. There is a default database. Are there any `--binlog-do-db' options? * Yes Do any of them match the database? * Yes Log the statement and exit. * No Ignore the statement and exit. * No Continue to step 4. 4. Do any of the `--binlog-ignore-db' options match the database? * Yes Ignore the statement and exit. * No Log the statement and exit. *Important*: For statement-based logging, an exception is made in the rules just given for the *Note `CREATE DATABASE': create-database, *Note `ALTER DATABASE': alter-database, and *Note `DROP DATABASE': drop-database. statements. In those cases, the database being _created, altered, or dropped_ replaces the default database when determining whether to log or ignore updates. `--binlog-do-db' can sometimes mean `ignore other databases'. For example, when using statement-based logging, a server running with only `--binlog-do-db=sales' does not write to the binary log statements for which the default database differs from `sales'. When using row-based logging with the same option, the server logs only those updates that change data in `sales'.  File: manual.info, Node: replication-rules-table-options, Next: replication-rules-examples, Prev: replication-rules-db-options, Up: replication-rules 16.2.3.2 Evaluation of Table-Level Replication Options ...................................................... The slave checks for and evaluates table options only if no matching database options were found (see *Note replication-rules-db-options::). First, as a preliminary condition, the slave checks whether statement-based replication is enabled. If so, and the statement occurs within a stored function, the slave executes the statement and exits. If row-based replication is enabled, the slave does not know whether a statement occurred within a stored function on the master, so this condition does not apply. *Note*: For statement-based replication, replication events represent statements (all changes making up a given event are associated with a single SQL statement); for row-based replication, each event represents a change in a single table row (thus a single statement such as `UPDATE mytable SET mycol = 1' may yield many row-based events). When viewed in terms of events, the process of checking table options is the same for both row-based and statement-based replication. Having reached this point, if there are no table options, the slave simply executes all events. If there are any `--replicate-do-table' or `--replicate-wild-do-table' options, the event must match one of these if it is to be executed; otherwise, it is ignored. If there are any `--replicate-ignore-table' or `--replicate-wild-ignore-table' options, all events are executed except those that match any of these options. This process is illustrated in the following diagram. Evaluation of Table-Level Filtering Rules in Replication The following steps describe this evaluation in more detail: 1. Are there any table options? * Yes Continue to step 2. * No Execute the event and exit. 2. Are there any `--replicate-do-table' options? * Yes Does the table match any of them? * Yes Execute the event and exit. * No Continue to step 3. * No Continue to step 3. 3. Are there any `--replicate-ignore-table' options? * Yes Does the table match any of them? * Yes Ignore the event and exit. * No Continue to step 4. * No Continue to step 4. 4. Are there any `--replicate-wild-do-table' options? * Yes Does the table match any of them? * Yes Execute the event and exit. * No Continue to step 5. * No Continue to step 5. 5. Are there any `--replicate-wild-ignore-table' options? * Yes Does the table match any of them? * Yes Ignore the event and exit. * No Continue to step 6. * No Continue to step 6. 6. Are there any `--replicate-do-table' or `--replicate-wild-do-table' options? * Yes Ignore the event and exit. * No Execute the event and exit.  File: manual.info, Node: replication-rules-examples, Prev: replication-rules-table-options, Up: replication-rules 16.2.3.3 Replication Rule Application ..................................... This section provides additional explanation and examples of usage for different combinations of replication filtering options. Some typical combinations of replication filter rule types are given in the following table: Condition (Types of Options) Outcome No `--replicate-*' options The slave executes all events that it at all: receives from the master. `--replicate-*-db' options, The slave accepts or ignores events using but no table options: the database options. It executes all events permitted by those options because there are no table restrictions. `--replicate-*-table' All events are accepted at the options, but no database database-checking stage because there are options: no database conditions. The slave executes or ignores events based solely on the table options. A combination of database The slave accepts or ignores events using and table options: the database options. Then it evaluates all events permitted by those options according to the table options. This can sometimes lead to results that seem counterintuitive, and that may be different depending on whether you are using statement-based or row-based replication; see the text for an example. A more complex example follows, in which we examine the outcomes for both statement-based and row-based settings. Suppose that we have two tables `mytbl1' in database `db1' and `mytbl2' in database `db2' on the master, and the slave is running with the following options (and no other replication filtering options): replicate-ignore-db = db1 replicate-do-table = db2.tbl2 Now we execute the following statements on the master: USE db1; INSERT INTO db2.tbl2 VALUES (1); The results on the slave vary considerably depending on the binary log format, and may not match initial expectations in either case. Statement-based replication The `USE' statement causes `db1' to be the default database. Thus the `--replicate-ignore-db' option matches, _and the *Note `INSERT': insert. statement is ignored_. The table options are not checked. Row-based replication The default database has no effect on how the slave reads database options when using row-based replication. Thus, the *Note `USE': use. statement makes no difference in how the `--replicate-ignore-db' option is handled: the database specified by this option does not match the database where the *Note `INSERT': insert. statement changes data, so the slave proceeds to check the table options. The table specified by `--replicate-do-table' matches the table to be updated, _and the row is inserted_.  File: manual.info, Node: replication-solutions, Next: replication-notes, Prev: replication-implementation, Up: replication 16.3 Replication Solutions ========================== * Menu: * replication-solutions-backups:: Using Replication for Backups * replication-solutions-diffengines:: Using Replication with Different Master and Slave Storage Engines * replication-solutions-scaleout:: Using Replication for Scale-Out * replication-solutions-partitioning:: Replicating Different Databases to Different Slaves * replication-solutions-performance:: Improving Replication Performance * replication-solutions-switch:: Switching Masters During Failover * replication-solutions-ssl:: Setting Up Replication Using SSL Replication can be used in many different environments for a range of purposes. This section provides general notes and advice on using replication for specific solution types. For information on using replication in a backup environment, including notes on the setup, backup procedure, and files to back up, see *Note replication-solutions-backups::. For advice and tips on using different storage engines on the master and slaves, see *Note replication-solutions-diffengines::. Using replication as a scale-out solution requires some changes in the logic and operation of applications that use the solution. See *Note replication-solutions-scaleout::. For performance or data distribution reasons, you may want to replicate different databases to different replication slaves. See *Note replication-solutions-partitioning:: As the number of replication slaves increases, the load on the master can increase and lead to reduced performance (because of the need to replicate the binary log to each slave). For tips on improving your replication performance, including using a single secondary server as an replication master, see *Note replication-solutions-performance::. For guidance on switching masters, or converting slaves into masters as part of an emergency failover solution, see *Note replication-solutions-switch::. To secure your replication communication, you can use SSL to encrypt the communication channel. For step-by-step instructions, see *Note replication-solutions-ssl::.  File: manual.info, Node: replication-solutions-backups, Next: replication-solutions-diffengines, Prev: replication-solutions, Up: replication-solutions 16.3.1 Using Replication for Backups ------------------------------------ * Menu: * replication-solutions-backups-mysqldump:: Backing Up a Slave Using `mysqldump' * replication-solutions-backups-rawdata:: Backing Up Raw Data from a Slave * replication-solutions-backups-read-only:: Backing Up a Master or Slave by Making It Read Only To use replication as a backup solution, replicate data from the master to a slave, and then back up the data slave. The slave can be paused and shut down without affecting the running operation of the master, so you can produce an effective snapshot of `live' data that would otherwise require the master to be shut down. How you back up a database depends on its size and whether you are backing up only the data, or the data and the replication slave state so that you can rebuild the slave in the event of failure. There are therefore two choices: * If you are using replication as a solution to enable you to back up the data on the master, and the size of your database is not too large, the *Note `mysqldump': mysqldump. tool may be suitable. See *Note replication-solutions-backups-mysqldump::. * For larger databases, where *Note `mysqldump': mysqldump. would be impractical or inefficient, you can back up the raw data files instead. Using the raw data files option also means that you can back up the binary and relay logs that will enable you to recreate the slave in the event of a slave failure. For more information, see *Note replication-solutions-backups-rawdata::. Another backup strategy, which can be used for either master or slave servers, is to put the server in a read-only state. The backup is performed against the read-only server, which then is changed back to its usual read/write operational status. See *Note replication-solutions-backups-read-only::.  File: manual.info, Node: replication-solutions-backups-mysqldump, Next: replication-solutions-backups-rawdata, Prev: replication-solutions-backups, Up: replication-solutions-backups 16.3.1.1 Backing Up a Slave Using `mysqldump' ............................................. Using *Note `mysqldump': mysqldump. to create a copy of a database enables you to capture all of the data in the database in a format that enables the information to be imported into another instance of MySQL Server (see *Note mysqldump::). Because the format of the information is SQL statements, the file can easily be distributed and applied to running servers in the event that you need access to the data in an emergency. However, if the size of your data set is very large, *Note `mysqldump': mysqldump. may be impractical. When using *Note `mysqldump': mysqldump, you should stop replication on the slave before starting the dump process to ensure that the dump contains a consistent set of data: 1. Stop the slave from processing requests. You can stop replication completely on the slave using *Note `mysqladmin': mysqladmin.: shell> mysqladmin stop-slave Alternatively, you can stop only the slave SQL thread to pause event execution: shell> mysql -e 'STOP SLAVE SQL_THREAD;' This enables the slave to continue to receive data change events from the master's binary log and store them in the relay logs using the I/O thread, but prevents the slave from executing these events and changing its data. Within busy replication environments, permitting the I/O thread to run during backup may speed up the catch-up process when you restart the slave SQL thread. 2. Run *Note `mysqldump': mysqldump. to dump your databases. You may either dump all databases or select databases to be dumped. For example, to dump all databases: shell> mysqldump --all-databases > fulldb.dump 3. Once the dump has completed, start slave operations again: shell> mysqladmin start-slave In the preceding example, you may want to add login credentials (user name, password) to the commands, and bundle the process up into a script that you can run automatically each day. If you use this approach, make sure you monitor the slave replication process to ensure that the time taken to run the backup does not affect the slave's ability to keep up with events from the master. See *Note replication-administration-status::. If the slave is unable to keep up, you may want to add another slave and distribute the backup process. For an example of how to configure this scenario, see *Note replication-solutions-partitioning::.  File: manual.info, Node: replication-solutions-backups-rawdata, Next: replication-solutions-backups-read-only, Prev: replication-solutions-backups-mysqldump, Up: replication-solutions-backups 16.3.1.2 Backing Up Raw Data from a Slave ......................................... To guarantee the integrity of the files that are copied, backing up the raw data files on your MySQL replication slave should take place while your slave server is shut down. If the MySQL server is still running, background tasks may still be updating the database files, particularly those involving storage engines with background processes such as `InnoDB'. With `InnoDB', these problems should be resolved during crash recovery, but since the slave server can be shut down during the backup process without affecting the execution of the master it makes sense to take advantage of this capability. To shut down the server and back up the files: 1. Shut down the slave MySQL server: shell> mysqladmin shutdown 2. Copy the data files. You can use any suitable copying or archive utility, including `cp', `tar' or `WinZip'. For example, assuming that the data directory is located under the current directory, you can archive the entire directory as follows: shell> tar cf /tmp/dbbackup.tar ./data 3. Start the MySQL server again. Under Unix: shell> mysqld_safe & Under Windows: C:\> "C:\Program Files\MySQL\MySQL Server 5.1\bin\mysqld" Normally you should back up the entire data directory for the slave MySQL server. If you want to be able to restore the data and operate as a slave (for example, in the event of failure of the slave), then in addition to the slave's data, you should also back up the slave status files, `master.info' and `relay-log.info', along with the relay log files. These files are needed to resume replication after you restore the slave's data. If you lose the relay logs but still have the `relay-log.info' file, you can check it to determine how far the SQL thread has executed in the master binary logs. Then you can use *Note `CHANGE MASTER TO': change-master-to. with the `MASTER_LOG_FILE' and `MASTER_LOG_POS' options to tell the slave to re-read the binary logs from that point. This requires that the binary logs still exist on the master server. If your slave is replicating *Note `LOAD DATA INFILE': load-data. statements, you should also back up any `SQL_LOAD-*' files that exist in the directory that the slave uses for this purpose. The slave needs these files to resume replication of any interrupted *Note `LOAD DATA INFILE': load-data. operations. The location of this directory is the value of the `--slave-load-tmpdir' option. If the server was not started with that option, the directory location is the value of the `tmpdir' system variable.  File: manual.info, Node: replication-solutions-backups-read-only, Prev: replication-solutions-backups-rawdata, Up: replication-solutions-backups 16.3.1.3 Backing Up a Master or Slave by Making It Read Only ............................................................ It is possible to back up either master or slave servers in a replication setup by acquiring a global read lock and manipulating the `read_only' system variable to change the read-only state of the server to be backed up: 1. Make the server read-only, so that it processes only retrievals and blocks updates. 2. Perform the backup. 3. Change the server back to its normal read/write state. *Note*: The instructions in this section place the server to be backed up in a state that is safe for backup methods that get the data from the server, such as *Note `mysqldump': mysqldump. (see *Note mysqldump::). You should not attempt to use these instructions to make a binary backup by copying files directly because the server may still have modified data cached in memory and not flushed to disk. These instructions also require MySQL 5.1.15 or higher. For earlier versions, setting `read_only' does not block while table locks or outstanding transactions are pending, so data changes can still occur during the backup operation and produce inconsistent backup results. The following instructions describe how to do this for a master server and for a slave server. For both scenarios discussed here, suppose that you have the following replication setup: * A master server M1 * A slave server S1 that has M1 as its master * A client C1 connected to M1 * A client C2 connected to S1 In either scenario, the statements to acquire the global read lock and manipulate the `read_only' variable are performed on the server to be backed up and do not propagate to any slaves of that server. *Scenario 1: Backup with a Read-Only Master* Put the master M1 in a read-only state by executing these statements on it: mysql> FLUSH TABLES WITH READ LOCK; mysql> SET GLOBAL read_only = ON; While M1 is in a read-only state, the following properties are true: * Requests for updates sent by C1 to M1 will block because the server is in read-only mode. * Requests for query results sent by C1 to M1 will succeed. * Making a backup on M1 is safe. * Making a backup on S1 is not safe. This server is still running, and might be processing the binary log or update requests coming from client C2 While M1 is read only, perform the backup. For example, you can use *Note `mysqldump': mysqldump. After the backup operation on M1 completes, restore M1 to its normal operational state by executing these statements: mysql> SET GLOBAL read_only = OFF; mysql> UNLOCK TABLES; Although performing the backup on M1 is safe (as far as the backup is concerned), it is not optimal for performance because clients of M1 are blocked from executing updates. This strategy applies to backing up a master server in a replication setup, but can also be used for a single server in a nonreplication setting. *Scenario 2: Backup with a Read-Only Slave* Put the slave S1 in a read-only state by executing these statements on it: mysql> FLUSH TABLES WITH READ LOCK; mysql> SET GLOBAL read_only = ON; While S1 is in a read-only state, the following properties are true: * The master M1 will continue to operate, so making a backup on the master is not safe. * The slave S1 is stopped, so making a backup on the slave S1 is safe. These properties provide the basis for a popular backup scenario: Having one slave busy performing a backup for a while is not a problem because it does not affect the entire network, and the system is still running during the backup. In particular, clients can still perform updates on the master server, which remains unaffected by backup activity on the slave. While S1 is read only, perform the backup. For example, you can use *Note `mysqldump': mysqldump. After the backup operation on S1 completes, restore S1 to its normal operational state by executing these statements: mysql> SET GLOBAL read_only = OFF; mysql> UNLOCK TABLES; After the slave is restored to normal operation, it again synchronizes to the master by catching up with any outstanding updates from the binary log of the master.  File: manual.info, Node: replication-solutions-diffengines, Next: replication-solutions-scaleout, Prev: replication-solutions-backups, Up: replication-solutions 16.3.2 Using Replication with Different Master and Slave Storage Engines ------------------------------------------------------------------------ It does not matter for the replication process whether the source table on the master and the replicated table on the slave use different engine types. In fact, the system variables `storage_engine' and `table_type' are not replicated. This provides a number of benefits in the replication process in that you can take advantage of different engine types for different replication scenarios. For example, in a typical scale-out scenario (see *Note replication-solutions-scaleout::), you want to use `InnoDB' tables on the master to take advantage of the transactional functionality, but use `MyISAM' on the slaves where transaction support is not required because the data is only read. When using replication in a data-logging environment you may want to use the `Archive' storage engine on the slave. Configuring different engines on the master and slave depends on how you set up the initial replication process: * If you used *Note `mysqldump': mysqldump. to create the database snapshot on your master, you could edit the dump file text to change the engine type used on each table. Another alternative for *Note `mysqldump': mysqldump. is to disable engine types that you do not want to use on the slave before using the dump to build the data on the slave. For example, you can add the `--skip-innodb' option on your slave to disable the `InnoDB' engine. If a specific engine does not exist for a table to be created, MySQL will use the default engine type, usually `MyISAM'. (This requires that the `NO_ENGINE_SUBSTITUTION' SQL mode is not enabled.) If you want to disable additional engines in this way, you may want to consider building a special binary to be used on the slave that only supports the engines you want. * If you are using raw data files (a binary backup) to set up the slave, you will be unable to change the initial table format. Instead, use *Note `ALTER TABLE': alter-table. to change the table types after the slave has been started. * For new master/slave replication setups where there are currently no tables on the master, avoid specifying the engine type when creating new tables. If you are already running a replication solution and want to convert your existing tables to another engine type, follow these steps: 1. Stop the slave from running replication updates: mysql> STOP SLAVE; This will enable you to change engine types without interruptions. 2. Execute an `ALTER TABLE ... ENGINE='ENGINE_TYPE'' for each table to be changed. 3. Start the slave replication process again: mysql> START SLAVE; Although the `storage_engine' and `table_type' variables are not replicated, be aware that *Note `CREATE TABLE': create-table. and *Note `ALTER TABLE': alter-table. statements that include the engine specification will be correctly replicated to the slave. For example, if you have a CSV table and you execute: mysql> ALTER TABLE csvtable Engine='MyISAM'; The above statement will be replicated to the slave and the engine type on the slave will be converted to `MyISAM', even if you have previously changed the table type on the slave to an engine other than CSV. If you want to retain engine differences on the master and slave, you should be careful to use the `storage_engine' variable on the master when creating a new table. For example, instead of: mysql> CREATE TABLE tablea (columna int) Engine=MyISAM; Use this format: mysql> SET storage_engine=MyISAM; mysql> CREATE TABLE tablea (columna int); When replicated, the `storage_engine' variable will be ignored, and the *Note `CREATE TABLE': create-table. statement will execute on the slave using the slave's default engine.  File: manual.info, Node: replication-solutions-scaleout, Next: replication-solutions-partitioning, Prev: replication-solutions-diffengines, Up: replication-solutions 16.3.3 Using Replication for Scale-Out -------------------------------------- You can use replication as a scale-out solution; that is, where you want to split up the load of database queries across multiple database servers, within some reasonable limitations. Because replication works from the distribution of one master to one or more slaves, using replication for scale-out works best in an environment where you have a high number of reads and low number of writes/updates. Most Web sites fit into this category, where users are browsing the Web site, reading articles, posts, or viewing products. Updates only occur during session management, or when making a purchase or adding a comment/message to a forum. Replication in this situation enables you to distribute the reads over the replication slaves, while still enabling your web servers to communicate with the replication master when a write is required. You can see a sample replication layout for this scenario in *Note figure_replication-scaleout::. FIGURE GOES HERE: Using Replication to Improve Performance During Scale-Out If the part of your code that is responsible for database access has been properly abstracted/modularized, converting it to run with a replicated setup should be very smooth and easy. Change the implementation of your database access to send all writes to the master, and to send reads to either the master or a slave. If your code does not have this level of abstraction, setting up a replicated system gives you the opportunity and motivation to clean it up. Start by creating a wrapper library or module that implements the following functions: * `safe_writer_connect()' * `safe_reader_connect()' * `safe_reader_statement()' * `safe_writer_statement()' `safe_' in each function name means that the function takes care of handling all error conditions. You can use different names for the functions. The important thing is to have a unified interface for connecting for reads, connecting for writes, doing a read, and doing a write. Then convert your client code to use the wrapper library. This may be a painful and scary process at first, but it pays off in the long run. All applications that use the approach just described are able to take advantage of a master/slave configuration, even one involving multiple slaves. The code is much easier to maintain, and adding troubleshooting options is trivial. You need modify only one or two functions; for example, to log how long each statement took, or which statement among those issued gave you an error. If you have written a lot of code, you may want to automate the conversion task by using the *Note `replace': replace-utility. utility that comes with standard MySQL distributions, or write your own conversion script. Ideally, your code uses consistent programming style conventions. If not, then you are probably better off rewriting it anyway, or at least going through and manually regularizing it to use a consistent style.  File: manual.info, Node: replication-solutions-partitioning, Next: replication-solutions-performance, Prev: replication-solutions-scaleout, Up: replication-solutions 16.3.4 Replicating Different Databases to Different Slaves ---------------------------------------------------------- There may be situations where you have a single master and want to replicate different databases to different slaves. For example, you may want to distribute different sales data to different departments to help spread the load during data analysis. A sample of this layout is shown in *Note figure_replication-multi-db::. FIGURE GOES HERE: Using Replication to Replicate Databases to Separate Replication Slaves You can achieve this separation by configuring the master and slaves as normal, and then limiting the binary log statements that each slave processes by using the `--replicate-wild-do-table' configuration option on each slave. *Important*: You should _not_ use `--replicate-do-db' for this purpose when using statement-based replication, since statement-based replication causes this option's affects to vary according to the database that is currently selected. This applies to mixed-format replication as well, since this enables some updates to be replicated using the statement-based format. However, it should be safe to use `--replicate-do-db' for this purpose if you are using row-based replication only, since in this case the currently selected database has no effect on the option's operation. For example, to support the separation as shown in *Note figure_replication-multi-db::, you should configure each replication slave as follows, before executing *Note `START SLAVE': start-slave.: * Replication slave 1 should use `--replicate-wild-do-table=databaseA.%'. * Replication slave 2 should use `--replicate-wild-do-table=databaseB.%'. * Replication slave 3 should use `--replicate-wild-do-table=databaseC.%'. Each slave in this configuration receives the entire binary log from the master, but executes only those events from the binary log that apply to the databases and tables included by the `--replicate-wild-do-table' option in effect on that slave. If you have data that must be synchronized to the slaves before replication starts, you have a number of choices: * Synchronize all the data to each slave, and delete the databases, tables, or both that you do not want to keep. * Use *Note `mysqldump': mysqldump. to create a separate dump file for each database and load the appropriate dump file on each slave. * Use a raw data file dump and include only the specific files and databases that you need for each slave. *Note*: This does not work with *Note `InnoDB': innodb-storage-engine. databases unless you use `innodb_file_per_table'.  File: manual.info, Node: replication-solutions-performance, Next: replication-solutions-switch, Prev: replication-solutions-partitioning, Up: replication-solutions 16.3.5 Improving Replication Performance ---------------------------------------- As the number of slaves connecting to a master increases, the load, although minimal, also increases, as each slave uses a client connection to the master. Also, as each slave must receive a full copy of the master binary log, the network load on the master may also increase and create a bottleneck. If you are using a large number of slaves connected to one master, and that master is also busy processing requests (for example, as part of a scale-out solution), then you may want to improve the performance of the replication process. One way to improve the performance of the replication process is to create a deeper replication structure that enables the master to replicate to only one slave, and for the remaining slaves to connect to this primary slave for their individual replication requirements. A sample of this structure is shown in *Note figure_replication-performance::. FIGURE GOES HERE: Using an Additional Replication Host to Improve Performance For this to work, you must configure the MySQL instances as follows: * Master 1 is the primary master where all changes and updates are written to the database. Binary logging should be enabled on this machine. * Master 2 is the slave to the Master 1 that provides the replication functionality to the remainder of the slaves in the replication structure. Master 2 is the only machine permitted to connect to Master 1. Master 2 also has binary logging enabled, and the `--log-slave-updates' option so that replication instructions from Master 1 are also written to Master 2's binary log so that they can then be replicated to the true slaves. * Slave 1, Slave 2, and Slave 3 act as slaves to Master 2, and replicate the information from Master 2, which actually consists of the upgrades logged on Master 1. The above solution reduces the client load and the network interface load on the primary master, which should improve the overall performance of the primary master when used as a direct database solution. If your slaves are having trouble keeping up with the replication process on the master, there are a number of options available: * If possible, put the relay logs and the data files on different physical drives. To do this, use the `--relay-log' option to specify the location of the relay log. * If the slaves are significantly slower than the master, you may want to divide up the responsibility for replicating different databases to different slaves. See *Note replication-solutions-partitioning::. * If your master makes use of transactions and you are not concerned about transaction support on your slaves, use `MyISAM' or another nontransactional engine on the slaves. See *Note replication-solutions-diffengines::. * If your slaves are not acting as masters, and you have a potential solution in place to ensure that you can bring up a master in the event of failure, then you can switch off `--log-slave-updates'. This prevents `dumb' slaves from also logging events they have executed into their own binary log.  File: manual.info, Node: replication-solutions-switch, Next: replication-solutions-ssl, Prev: replication-solutions-performance, Up: replication-solutions 16.3.6 Switching Masters During Failover ---------------------------------------- There is currently no official solution for providing failover between master and slaves in the event of a failure. With the currently available features, you would have to set up a master and a slave (or several slaves), and to write a script that monitors the master to check whether it is up. Then instruct your applications and the slaves to change master in case of failure. Remember that you can tell a slave to change its master at any time, using the *Note `CHANGE MASTER TO': change-master-to. statement. The slave will not check whether the databases on the master are compatible with the slave, it will just start reading and executing events from the specified binary log coordinates on the new master. In a failover situation, all the servers in the group are typically executing the same events from the same binary log file, so changing the source of the events should not affect the database structure or integrity providing you are careful. Run your slaves with the `--log-bin' option and without `--log-slave-updates'. In this way, the slave is ready to become a master as soon as you issue *Note `STOP SLAVE': stop-slave.; *Note `RESET MASTER': reset-master, and *Note `CHANGE MASTER TO': change-master-to. statement on the other slaves. For example, assume that you have the structure shown in *Note figure_replication-redundancy-before::. FIGURE GOES HERE: Redundancy Using Replication, Initial Structure In this diagram, the `MySQL Master' holds the master database, the `MySQL Slave' hosts are replication slaves, and the `Web Client' machines are issuing database reads and writes. Web clients that issue only reads (and would normally be connected to the slaves) are not shown, as they do not need to switch to a new server in the event of failure. For a more detailed example of a read/write scale-out replication structure, see *Note replication-solutions-scaleout::. Each MySQL Slave (`Slave 1', `Slave 2', and `Slave 3') is a slave running with `--log-bin' and without `--log-slave-updates'. Because updates received by a slave from the master are not logged in the binary log unless `--log-slave-updates' is specified, the binary log on each slave is empty initially. If for some reason `MySQL Master' becomes unavailable, you can pick one of the slaves to become the new master. For example, if you pick `Slave 1', all `Web Clients' should be redirected to `Slave 1', which will log updates to its binary log. `Slave 2' and `Slave 3' should then replicate from `Slave 1'. The reason for running the slave without `--log-slave-updates' is to prevent slaves from receiving updates twice in case you cause one of the slaves to become the new master. Suppose that `Slave 1' has `--log-slave-updates' enabled. Then it will write updates that it receives from `Master' to its own binary log. When `Slave 2' changes from `Master' to `Slave 1' as its master, it may receive updates from `Slave 1' that it has already received from `Master' Make sure that all slaves have processed any statements in their relay log. On each slave, issue `STOP SLAVE IO_THREAD', then check the output of *Note `SHOW PROCESSLIST': show-processlist. until you see `Has read all relay log'. When this is true for all slaves, they can be reconfigured to the new setup. On the slave `Slave 1' being promoted to become the master, issue *Note `STOP SLAVE': stop-slave. and *Note `RESET MASTER': reset-master. On the other slaves `Slave 2' and `Slave 3', use *Note `STOP SLAVE': stop-slave. and `CHANGE MASTER TO MASTER_HOST='Slave1'' (where `'Slave1'' represents the real host name of `Slave 1'). To use *Note `CHANGE MASTER TO': change-master-to, add all information about how to connect to `Slave 1' from `Slave 2' or `Slave 3' (USER, PASSWORD, PORT). In *Note `CHANGE MASTER TO': change-master-to, there is no need to specify the name of the `Slave 1' binary log file or log position to read from: We know it is the first binary log file and position 4, which are the defaults for *Note `CHANGE MASTER TO': change-master-to. Finally, use *Note `START SLAVE': start-slave. on `Slave 2' and `Slave 3'. Once the new replication is in place, you will then need to instruct each `Web Client' to direct its statements to `Slave 1'. From that point on, all updates statements sent by `Web Client' to `Slave 1' are written to the binary log of `Slave 1', which then contains every update statement sent to `Slave 1' since `Master' died. The resulting server structure is shown in *Note figure_replication-redundancy-after::. FIGURE GOES HERE: Redundancy Using Replication, After Master Failure When `Master' is up again, you must issue on it the same *Note `CHANGE MASTER TO': change-master-to. as that issued on `Slave 2' and `Slave 3', so that `Master' becomes a slave of `S1' and picks up each `Web Client' writes that it missed while it was down. To make `Master' a master again (for example, because it is the most powerful machine), use the preceding procedure as if `Slave 1' was unavailable and `Master' was to be the new master. During this procedure, do not forget to run *Note `RESET MASTER': reset-master. on `Master' before making `Slave 1', `Slave 2', and `Slave 3' slaves of `Master'. Otherwise, they may pick up old `Web Client' writes from before the point at which `Master' became unavailable. Note that there is no synchronization between the different slaves to a master. Some slaves might be ahead of others. This means that the concept outlined in the previous example might not work. In practice, however, the relay logs of different slaves will most likely not be far behind the master, so it would work, anyway (but there is no guarantee). A good way to keep your applications informed as to the location of the master is by having a dynamic DNS entry for the master. With `bind' you can use `nsupdate' to dynamically update your DNS.  File: manual.info, Node: replication-solutions-ssl, Prev: replication-solutions-switch, Up: replication-solutions 16.3.7 Setting Up Replication Using SSL --------------------------------------- To use SSL for encrypting the transfer of the binary log required during replication, both the master and the slave must support SSL network connections. If either host does not support SSL connections (because it has not been compiled or configured for SSL), replication through an SSL connection is not possible. Setting up replication using an SSL connection is similar to setting up a server and client using SSL. You must obtain (or create) a suitable security certificate that you can use on the master, and a similar certificate (from the same certificate authority) on each slave. For more information on setting up a server and client for SSL connectivity, see *Note secure-using-ssl::. To enable SSL on the master you must create or obtain suitable certificates, and then add the following configuration options to the master's configuration within the `[mysqld]' section of the master's `my.cnf' file: [mysqld] ssl-ca=CACERT.PEM ssl-cert=SERVER-CERT.PEM ssl-key=SERVER-KEY.PEM The paths to the certificates may be relative or absolute; we recommend that you always use complete paths for this purpose. The options are as follows: * `ssl-ca' identifies the Certificate Authority (CA) certificate. * `ssl-cert' identifies the server public key. This can be sent to the client and authenticated against the CA certificate that it has. * `ssl-key' identifies the server private key. On the slave, you have two options available for setting the SSL information. You can either add the slave certificates to the `[client]' section of the slave's `my.cnf' file, or you can explicitly specify the SSL information using the *Note `CHANGE MASTER TO': change-master-to. statement: * To add the slave certificates using an option file, add the following lines to the `[client]' section of the slave's `my.cnf' file: [client] ssl-ca=CACERT.PEM ssl-cert=CLIENT-CERT.PEM ssl-key=CLIENT-KEY.PEM Restart the slave server, using the `--skip-slave-start' option to prevent the slave from connecting to the master. Use *Note `CHANGE MASTER TO': change-master-to. to specify the master configuration, using the `MASTER_SSL' option to enable SSL connectivity: mysql> CHANGE MASTER TO -> MASTER_HOST='master_hostname', -> MASTER_USER='replicate', -> MASTER_PASSWORD='password', -> MASTER_SSL=1; * To specify the SSL certificate options using the *Note `CHANGE MASTER TO': change-master-to. statement, append the SSL options: mysql> CHANGE MASTER TO -> MASTER_HOST='master_hostname', -> MASTER_USER='replicate', -> MASTER_PASSWORD='password', -> MASTER_SSL=1, -> MASTER_SSL_CA = 'ca_file_name', -> MASTER_SSL_CAPATH = 'ca_directory_name', -> MASTER_SSL_CERT = 'cert_file_name', -> MASTER_SSL_KEY = 'key_file_name'; After the master information has been updated, start the slave replication process: mysql> START SLAVE; You can use the *Note `SHOW SLAVE STATUS': show-slave-status. statement to confirm that the SSL connection was established successfully. For more information on the *Note `CHANGE MASTER TO': change-master-to. statement, see *Note change-master-to::. If you want to enforce the use of SSL connections during replication, then create a user with the `REPLICATION SLAVE' privilege and use the `REQUIRE SSL' option for that user. For example: mysql> CREATE USER 'repl'@'%.mydomain.com' IDENTIFIED BY 'slavepass'; mysql> GRANT REPLICATION SLAVE ON *.* -> TO 'repl'@'%.mydomain.com' REQUIRE SSL; If the account already exists, you can add `REQUIRE SSL' to it with this statement: mysql> GRANT USAGE ON *.* -> TO 'repl'@'%.mydomain.com' REQUIRE SSL;  File: manual.info, Node: replication-notes, Prev: replication-solutions, Up: replication 16.4 Replication Notes and Tips =============================== * Menu: * replication-features:: Replication Features and Issues * replication-compatibility:: Replication Compatibility Between MySQL Versions * replication-upgrade:: Upgrading a Replication Setup * replication-faq:: Replication FAQ * replication-problems:: Troubleshooting Replication * replication-bugs:: How to Report Replication Bugs or Problems  File: manual.info, Node: replication-features, Next: replication-compatibility, Prev: replication-notes, Up: replication-notes 16.4.1 Replication Features and Issues -------------------------------------- * Menu: * replication-features-auto-increment:: Replication and `AUTO_INCREMENT' * replication-features-charset:: Replication and Character Sets * replication-features-create-if-not-exists:: Replication of `CREATE ... IF NOT EXISTS' Statements * replication-features-create-select:: Replication of `CREATE TABLE ... SELECT' Statements * replication-features-current-user:: Replication of `CURRENT_USER()' * replication-features-drop-if-exists:: Replication of `DROP ... IF EXISTS' Statements * replication-features-differing-tables:: Replication with Differing Table Definitions on Master and Slave * replication-features-directory:: Replication and `DIRECTORY' Table Options * replication-features-invoked:: Replication of Invoked Features * replication-features-floatvalues:: Replication and Floating-Point Values * replication-features-flush:: Replication and `FLUSH' * replication-features-functions:: Replication and System Functions * replication-features-limit:: Replication and `LIMIT' * replication-features-load-data:: Replication and `LOAD DATA INFILE' * replication-features-logging:: Replication and the Slow Query Log * replication-features-repair-table:: Replication and `REPAIR TABLE' * replication-features-shutdowns:: Replication and Master or Slave Shutdowns * replication-features-max-allowed-packet:: Replication and `max_allowed_packet' * replication-features-memory:: Replication and `MEMORY' Tables * replication-features-temptables:: Replication and Temporary Tables * replication-features-mysqldb:: Replication of the `mysql' System Database * replication-features-optimizer:: Replication and the Query Optimizer * replication-features-reserved-words:: Replication and Reserved Words * replication-features-set-password:: `SET PASSWORD' and Row-Based Replication * replication-features-slaveerrors:: Slave Errors During Replication * replication-features-sql-mode:: Replication and Server SQL Mode * replication-features-timeout:: Replication Retries and Timeouts * replication-features-timestamp:: Replication and `TIMESTAMP' * replication-features-timezone:: Replication and Time Zones * replication-features-transactions:: Replication and Transactions * replication-features-triggers:: Replication and Triggers * replication-features-views:: Replication and Views * replication-features-truncate:: Replication and `TRUNCATE TABLE' * replication-features-variables:: Replication and Variables The following sections provide information about what is supported and what is not in MySQL replication, and about specific issues and situations that may occur when replicating certain statements. Statement-based replication depends on compatibility at the SQL level between the master and slave. In others, successful SBR requires that any SQL features used be supported by both the master and the slave servers. For example, if you use a feature on the master server that is available only in MySQL 5.1 (or later), you cannot replicate to a slave that uses MySQL 5.0 (or earlier). Such incompatibilities also can occur within a release series when using pre-production releases of MySQL. For example, the `SLEEP()' function is available beginning with MySQL 5.0.12. If you use this function on the master, you cannot replicate to a slave that uses MySQL 5.0.11 or earlier. For this reason, use Generally Available (GA) releases of MySQL for statement-based replication in a production setting, since we do not introduce new SQL statements or change their behavior within a given release series once that series reaches GA release status. If you are planning to use statement-based replication between MySQL 5.1 and a previous MySQL release series, it is also a good idea to consult the edition of the `MySQL Reference Manual' corresponding to the earlier release series for information regarding the replication characteristics of that series. With MySQL's statement-based replication, there may be issues with replicating stored routines or triggers. You can avoid these issues by using MySQL's row-based replication instead. For a detailed list of issues, see *Note stored-programs-logging::. For more information about row-based logging and row-based replication, see *Note binary-log-formats::, and *Note replication-formats::. For additional information specific to replication and `InnoDB', see *Note innodb-and-mysql-replication::. For information relating to replication with MySQL Cluster, see *Note mysql-cluster-replication::.  File: manual.info, Node: replication-features-auto-increment, Next: replication-features-charset, Prev: replication-features, Up: replication-features 16.4.1.1 Replication and `AUTO_INCREMENT' ......................................... Statement-based replication of `AUTO_INCREMENT', `LAST_INSERT_ID()', and *Note `TIMESTAMP': datetime. values is done correctly, subject to the following exceptions: * Prior to MySQL 5.1.12, a stored procedure that uses `LAST_INSERT_ID()' does not replicate properly using statement-based binary logging. * Prior to MySQL 5.1.12, when a stored routine or trigger caused an *Note `INSERT': insert. into an `AUTO_INCREMENT' column, the generated `AUTO_INCREMENT' value was not written into the binary log, so a different value could in some cases be inserted on the slave. * An insert into an `AUTO_INCREMENT' column caused by a stored routine or trigger running on a master that uses MySQL 5.0.60 or earlier does not replicate correctly to a slave running MySQL 5.1.12 through 5.1.23 (inclusive). (Bug#33029) A statement invoking a trigger or function that causes an update to an `AUTO_INCREMENT' column is not replicated correctly using statement-based replication. Beginning with MySQL 5.1.40, such statements are marked as unsafe. (Bug#45677) * The `AUTO_INCREMENT' table option was not replicated correctly prior to MySQL 5.1.31. (Bug#41986) * Adding an `AUTO_INCREMENT' column to a table with *Note `ALTER TABLE': alter-table. might not produce the same ordering of the rows on the slave and the master. This occurs because the order in which the rows are numbered depends on the specific storage engine used for the table and the order in which the rows were inserted. If it is important to have the same order on the master and slave, the rows must be ordered before assigning an `AUTO_INCREMENT' number. Assuming that you want to add an `AUTO_INCREMENT' column to a table `t1' that has columns `col1' and `col2', the following statements produce a new table `t2' identical to `t1' but with an `AUTO_INCREMENT' column: CREATE TABLE t2 LIKE t1; ALTER TABLE t2 ADD id INT AUTO_INCREMENT PRIMARY KEY; INSERT INTO t2 SELECT * FROM t1 ORDER BY col1, col2; *Important*: To guarantee the same ordering on both master and slave, the `ORDER BY' clause must name _all_ columns of `t1'. The instructions just given are subject to the limitations of `CREATE TABLE ... LIKE': Foreign key definitions are ignored, as are the `DATA DIRECTORY' and `INDEX DIRECTORY' table options. If a table definition includes any of those characteristics, create `t2' using a *Note `CREATE TABLE': create-table. statement that is identical to the one used to create `t1', but with the addition of the `AUTO_INCREMENT' column. Regardless of the method used to create and populate the copy having the `AUTO_INCREMENT' column, the final step is to drop the original table and then rename the copy: DROP t1; ALTER TABLE t2 RENAME t1; See also *Note alter-table-problems::.  File: manual.info, Node: replication-features-charset, Next: replication-features-create-if-not-exists, Prev: replication-features-auto-increment, Up: replication-features 16.4.1.2 Replication and Character Sets ....................................... The following applies to replication between MySQL servers that use different character sets: * If the master uses MySQL 4.1, you must _always_ use the same _global_ character set and collation on the master and the slave, regardless of the slave MySQL version. (These are controlled by the `--character-set-server' and `--collation-server' options.) Otherwise, you may get duplicate-key errors on the slave, because a key that is unique in the master character set might not be unique in the slave character set. Note that this is not a cause for concern when master and slave are both MySQL 5.0 or later. * If the master is older than MySQL 4.1.3, the character set of any client should never be made different from its global value because this character set change is not known to the slave. In other words, clients should not use `SET NAMES', `SET CHARACTER SET', and so forth. If both the master and the slave are 4.1.3 or newer, clients can freely set session values for character set variables because these settings are written to the binary log and so are known to the slave. That is, clients can use `SET NAMES' or `SET CHARACTER SET' or can set variables such as `collation_client' or `collation_server'. However, clients are prevented from changing the _global_ value of these variables; as stated previously, the master and slave must always have identical global character set values. This is true whether you are using statement-based or row-based replication. * If the master has databases with a character set different from the global `character_set_server' value, you should design your *Note `CREATE TABLE': create-table. statements so that they do not implicitly rely on the database default character set. A good workaround is to state the character set and collation explicitly in *Note `CREATE TABLE': create-table. statements.  File: manual.info, Node: replication-features-create-if-not-exists, Next: replication-features-create-select, Prev: replication-features-charset, Up: replication-features 16.4.1.3 Replication of `CREATE ... IF NOT EXISTS' Statements ............................................................. This section discusses the rules that are applied when various `CREATE ... IF NOT EXISTS' statements are replicated. Previous to MySQL 5.1.38 *Note `CREATE DATABASE IF NOT EXISTS': create-database. was replicated only if the database named in the statement did not exist on the master. *Note `CREATE TABLE IF NOT EXISTS': create-table. was replicated only if the table named in the statement did not exist on the master. MySQL 5.1.39 and later Every *Note `CREATE DATABASE IF NOT EXISTS': create-database. statement is replicated, whether or not the database already exists on the master. Similarly, every *Note `CREATE TABLE IF NOT EXISTS': create-table. statement is replicated, whether or not the table already exists on the master. This includes *Note `CREATE TABLE IF NOT EXISTS ... LIKE': create-table. However, replication of *Note `CREATE TABLE IF NOT EXISTS ... SELECT': create-table. follows somewhat different rules; see *Note replication-features-create-select::, for more information. Replication of `CREATE EVENT IF NOT EXISTS' *Note `CREATE EVENT IF NOT EXISTS': create-event. is always replicated, whether or not the event named in the statement already exists on the master. This is true for all MySQL 5.1 releases beginning with MySQL 5.1.6, when this statement was introduced. See also Bug#45574.  File: manual.info, Node: replication-features-create-select, Next: replication-features-current-user, Prev: replication-features-create-if-not-exists, Up: replication-features 16.4.1.4 Replication of `CREATE TABLE ... SELECT' Statements ............................................................ This section discusses how MySQL replicates *Note `CREATE TABLE ... SELECT': create-table-select. statements. These behaviors are not dependent on MySQL version: * *Note `CREATE TABLE ... SELECT': create-table-select. always performs an implicit commit (*Note implicit-commit::). * If destination table does not exist, logging occurs as follows. It does not matter whether `IF NOT EXISTS' is present. * `STATEMENT' or `MIXED' format: The statement is logged as written. * `ROW' format: The statement is logged as a *Note `CREATE TABLE': create-table. statement followed by a series of insert-row events. * If the statement fails, nothing is logged. This includes the case that the destination table exists and `IF NOT EXISTS' is not given. When the destination table exists and `IF NOT EXISTS' is given, MySQL handles the statement in a version-dependent way. In MySQL 5.1 before 5.1.51 and in MySQL 5.5 before 5.5.6 (this is the original behavior): * `STATEMENT' or `MIXED' format: The statement is logged as written. * `ROW' format: The statement is logged as a *Note `CREATE TABLE': create-table. statement followed by a series of insert-row events. In MySQL 5.1 as of 5.1.51: * `STATEMENT' or `MIXED' format: The statement is logged as the equivalent pair of *Note `CREATE TABLE': create-table. and *Note `INSERT INTO ... SELECT': insert-select. statements. * `ROW' format: The statement is logged as a *Note `CREATE TABLE': create-table. statement followed by a series of insert-row events. In MySQL 5.5 as of 5.5.6: * Nothing is inserted or logged. These version dependencies arise due to a change in MySQL 5.5.6 in handling of *Note `CREATE TABLE ... SELECT': create-table-select. not to insert rows if the destination table already exists, and a change made in MySQL 5.1.51 to preserve forward compatibility in replication of such statements from a 5.1 master to a 5.5 slave. For details, see *Note create-table-select::.  File: manual.info, Node: replication-features-current-user, Next: replication-features-drop-if-exists, Prev: replication-features-create-select, Up: replication-features 16.4.1.5 Replication of `CURRENT_USER()' ........................................ The following statements support use of the `CURRENT_USER()' function to take the place of the name of (and, possibly, the host for) an affected user or a definer; in such cases, `CURRENT_USER()' is expanded where and as needed: * *Note `DROP USER': drop-user. * *Note `RENAME USER': rename-user. * *Note `GRANT': grant. * *Note `REVOKE': revoke. * *Note `CREATE FUNCTION': create-function. * *Note `CREATE PROCEDURE': create-procedure. * *Note `CREATE TRIGGER': create-trigger. * *Note `CREATE EVENT': create-event. * *Note `CREATE VIEW': create-view. * *Note `ALTER EVENT': alter-event. * *Note `ALTER VIEW': alter-view. * *Note `SET PASSWORD': set-password. In all MySQL 5.1 releases, when `CURRENT_USER()' and `CURRENT_USER' is used as the definer in any of the statements *Note `CREATE FUNCTION': create-function, *Note `CREATE PROCEDURE': create-procedure, *Note `CREATE TRIGGER': create-trigger, *Note `CREATE EVENT': create-event, *Note `CREATE VIEW': create-view, or *Note `ALTER VIEW': alter-view. when binary logging is enabled, the function reference is expanded before it is written to the binary log, so that the statement refers to the same user on both the master and the slave when the statement is replicated. Beginning with MySQL 5.1.49, `CURRENT_USER()' or `CURRENT_USER' is also expanded prior to being written to the binary log when used in *Note `DROP USER': drop-user, *Note `RENAME USER': rename-user, *Note `GRANT': grant, *Note `REVOKE': revoke, or *Note `ALTER EVENT': alter-event. (Bug#48321)  File: manual.info, Node: replication-features-drop-if-exists, Next: replication-features-differing-tables, Prev: replication-features-current-user, Up: replication-features 16.4.1.6 Replication of `DROP ... IF EXISTS' Statements ....................................................... The *Note `DROP DATABASE IF EXISTS': drop-database, *Note `DROP TABLE IF EXISTS': drop-table, and *Note `DROP VIEW IF EXISTS': drop-view. statements are always replicated, even if the database, table, or view to be dropped does not exist on the master. This is to ensure that the object to be dropped no longer exists on either the master or the slave, once the slave has caught up with the master. Beginning with MySQL 5.1.33, `DROP ... IF EXISTS' statements for stored programs (stored procedures and functions, triggers, and events) are also replicated, even if the stored program to be dropped does not exist on the master. (Bug#13684)  File: manual.info, Node: replication-features-differing-tables, Next: replication-features-directory, Prev: replication-features-drop-if-exists, Up: replication-features 16.4.1.7 Replication with Differing Table Definitions on Master and Slave ......................................................................... * Menu: * replication-features-more-columns:: Replication with More Columns on Master or Slave * replication-features-different-data-types:: Replication of Columns Having Different Data Types Starting with MySQL 5.1.21, source and target tables for replication do not have to be identical. A table on the master can have more or fewer columns than the slave's copy of the table. In addition, corresponding table columns on the master and the slave can use different data types, subject to certain conditions. In all cases where the source and target tables do not have identical definitions, the following must be true for replication to work: * You must be using row-based replication. (Using `MIXED' for the binary logging format does not work.) * The database and table names must be the same on both the master and the slave. Additional conditions are discussed, with examples, in the following two sections.  File: manual.info, Node: replication-features-more-columns, Next: replication-features-different-data-types, Prev: replication-features-differing-tables, Up: replication-features-differing-tables 16.4.1.8 Replication with More Columns on Master or Slave ......................................................... Starting with MySQL 5.1.21, you can replicate a table from the master to the slave such that the master and slave copies of the table have differing numbers of columns, subject to the following conditions: * Columns common to both versions of the table must be defined in the same order on the master and the slave. (This is true even if both tables have the same number of columns.) * Columns common to both versions of the table must be defined before any additional columns. This means that executing an *Note `ALTER TABLE': alter-table. statement on the slave where a new column is inserted into the table within the range of columns common to both tables causes replication to fail, as shown in the following example: Suppose that a table `t', existing on the master and the slave, is defined by the following *Note `CREATE TABLE': create-table. statement: CREATE TABLE t ( c1 INT, c2 INT, c3 INT ); Suppose that the *Note `ALTER TABLE': alter-table. statement shown here is executed on the slave: ALTER TABLE t ADD COLUMN cnew1 INT AFTER c3; The previous *Note `ALTER TABLE': alter-table. is permitted on the slave because the columns `c1', `c2', and `c3' that are common to both versions of table `t' remain grouped together in both versions of the table, before any columns that differ. However, the following *Note `ALTER TABLE': alter-table. statement cannot be executed on the slave without causing replication to break: ALTER TABLE t ADD COLUMN cnew2 INT AFTER c3; Replication fails after execution on the slave of the *Note `ALTER TABLE': alter-table. statement just shown, because the new column `cnew2' comes between columns common to both versions of `t'. * Each `extra' column in the version of the table having more columns must have a default value. *Note*: A column's default value is determined by a number of factors, including its type, whether it is defined with a `DEFAULT' option, whether it is declared as `NULL', and the server SQL mode in effect at the time of its creation; for more information, see *Note data-type-defaults::). In addition, when the slave's copy of the table has more columns than the master's copy, each column common to the tables must use the same data type in both tables. Examples The following examples illustrate some valid and invalid table definitions: More columns on the master The following table definitions are valid and replicate correctly: master> CREATE TABLE t1 (c1 INT, c2 INT, c3 INT); slave> CREATE TABLE t1 (c1 INT, c2 INT); The following table definitions would raise Error 1532 (`ER_BINLOG_ROW_RBR_TO_SBR') because the definitions of the columns common to both versions of the table are in a different order on the slave than they are on the master: master> CREATE TABLE t1 (c1 INT, c2 INT, c3 INT); slave> CREATE TABLE t1 (c2 INT, c1 INT); The following table definitions would also raise Error 1532 because the definition of the extra column on the master appears before the definitions of the columns common to both versions of the table: master> CREATE TABLE t1 (c3 INT, c1 INT, c2 INT); slave> CREATE TABLE t1 (c1 INT, c2 INT); More columns on the slave The following table definitions are valid and replicate correctly: master> CREATE TABLE t1 (c1 INT, c2 INT); slave> CREATE TABLE t1 (c1 INT, c2 INT, c3 INT); The following definitions raise Error 1532 because the columns common to both versions of the table are not defined in the same order on both the master and the slave: master> CREATE TABLE t1 (c1 INT, c2 INT); slave> CREATE TABLE t1 (c2 INT, c1 INT, c3 INT); The following table definitions also raise Error 1532 because the definition for the extra column in the slave's version of the table appears before the definitions for the columns which are common to both versions of the table: master> CREATE TABLE t1 (c1 INT, c2 INT); slave> CREATE TABLE t1 (c3 INT, c1 INT, c2 INT); The following table definitions fail because the slave's version of the table has additional columns compared to the master's version, and the two versions of the table use different data types for the common column `c2': master> CREATE TABLE t1 (c1 INT, c2 BIGINT); slave> CREATE TABLE t1 (c1 INT, c2 INT, c3 INT);  File: manual.info, Node: replication-features-different-data-types, Prev: replication-features-more-columns, Up: replication-features-differing-tables 16.4.1.9 Replication of Columns Having Different Data Types ........................................................... Corresponding columns on the master's and the slave's copies of the same table ideally should have the same data type. However, beginning with MySQL 5.1.21, this is not always strictly enforced, as long as certain conditions are met. All other things being equal, it is always possible to replicate from a column of a given data type to another column of the same type and same size or width, where applicable, or larger. For example, you can replicate from a `CHAR(10)' column to another `CHAR(10)', or from a `CHAR(10)' column to a `CHAR(25)' column without any problems. In certain cases, it also possible to replicate from a column having one data type (on the master) to a column having a different data type (on the slave); when the data type of the master's version of the column is promoted to a type that is the same size or larger on the slave, this is known as _attribute promotion_. Attribute promotion can be used with both statement-based and row-based replication, and is not dependent on the storage engine used by either the master or the slave. However, the choice of logging format does have an effect on the type conversions that are permitted; the particulars are discussed later in this section. *Important*: Whether you use statement-based or row-based replication, the slave's copy of the table cannot contain more columns than the master's copy if you wish to employ attribute promotion. Statement-based replication When using statement-based replication, a simple rule of thumb to follow is, `If the statement run on the master would also execute successfully on the slave, it should also replicate successfully'. In other words, if the statement uses a value that is compatible with the type of a given column on the slave, the statement can be replicated. For example, you can insert any value that fits in a `TINYINT' column into a `BIGINT' column as well; it follows that, even if you change the type of a `TINYINT' column in the slave's copy of a table to `BIGINT', any insert into that column on the master that succeeds should also succeed on the slave, since it is impossible to have a legal `TINYINT' value that is large enough to exceed a `BIGINT' column. *Note*: The restrictions described in the next few paragraphs do not apply to MySQL Cluster Replication, beginning with MySQL Cluster NDB 6.3.33, 7.0.14, and 7.1.3. These and later versions of MySQL Cluster support attribute promotion and demotion (such as *Note `TINYINT': numeric-types. to *Note `BIGINT': numeric-types, and *Note `VARCHAR(50)': char. to *Note `CHAR(25)': char, respectively) in replication; see *Note replication-features-attribute-promotion::, for more information. Row-based replication For row-based replication, the case is not so simple, due to the fact that changes rather than statements are replicated, and these changes are transmitted from master to slave using formats that do not always map directly to MySQL server column data types. For example, with row-based binary logging, you cannot replicate between different `INT' subtypes, such as from `TINYINT' to `BIGINT', because changes to columns of these types are represented differently from one another in the binary log when using row-based logging. However, you can replicate from `BLOB' to `TEXT' using row-based replication because changes to `BLOB' and `TEXT' columns are represented using the same format in the binary log. Supported conversions for attribute promotion when using row-based replication are shown in the following table: From (Master) To (Slave) *Note `BINARY': binary-varbinary. *Note `CHAR': char. *Note `BLOB': blob. *Note `TEXT': blob. *Note `CHAR': char. *Note `BINARY': binary-varbinary. *Note `DECIMAL': numeric-types. *Note `NUMERIC': numeric-types. *Note `NUMERIC': numeric-types. *Note `DECIMAL': numeric-types. *Note `TEXT': blob. *Note `BLOB': blob. *Note `VARBINARY': binary-varbinary. *Note `VARCHAR': char. *Note `VARCHAR': char. *Note `VARBINARY': binary-varbinary. *Note*: In all cases, the size or width of the column on the slave must be equal to or greater than that of the column on the master. For example, you can replicate from a `CHAR(10)' column on the master to a column that uses `BINARY(10)' or `BINARY(25)' on the slave, but you cannot replicate from a `CHAR(10)' column on the master to `BINARY(5)' column on the slave. For *Note `DECIMAL': numeric-types. and *Note `NUMERIC': numeric-types. columns, both the mantissa (_M_) and the number of decimals (_D_) must be the same size or larger on the slave as compared with the master. For example, replication from a `NUMERIC(5,4)' to a `DECIMAL(6,4)' works, but not from a `NUMERIC(5,4)' to a `DECIMAL(5,3)'. MySQL (except for MySQL Cluster) does _not_ support attribute promotion of any of the following data types to or from any other data type when using row-based replication: * *Note `INT': numeric-types. (including `TINYINT', `SMALLINT', `MEDIUMINT', `BIGINT'). Promotion between *Note `INT': numeric-types. subtypes--for example, from `SMALLINT' to `BIGINT'--is also not supported. * *Note `SET': set. or *Note `ENUM': enum. * *Note `FLOAT': numeric-types. or *Note `DOUBLE': numeric-types. * All of the data types relating to dates, times, or both: *Note `DATE': datetime, *Note `TIME': time, *Note `DATETIME': datetime, *Note `TIMESTAMP': datetime, and *Note `YEAR': year. Attribute promotion and demotion (MySQL Cluster) Beginning with MySQL Cluster NDB 6.3.33, 7.0.14, and 7.1.3, MySQL Cluster Replication supports attribute promotion and demotion between smaller data types and larger types. It is also possible to specify whether or not to permit lossy (truncated) or non-lossy conversions of demoted column values, as explained later in this section. Lossy and non-lossy conversions In the event that the target type cannot represent the value being inserted, a decision must be made on how to handle the conversion. If we permit the conversion but truncate (or otherwise modify) the source value to achieve a `fit' in the target column, we make what is known as a _lossy conversion_. A conversion which does not require truncation or similar modifications to fit the source column value in the target column is a _non-lossy_ conversion. Type conversion modes (`slave_type_conversions' variable) The setting of the `slave_type_conversions' global server variable controls the type conversion mode used on the slave. This variable takes a set of values from the following table, which shows the effects of each mode on the slave's type-conversion behavior: Mode Effect `ALL_LOSSY' In this mode, type conversions that would mean loss of information are permitted. This does not imply that non-lossy conversions are permitted, merely that only cases requiring either lossy conversions or no conversion at all are permitted; for example, enabling _only_ this mode permits an `INT' column to be converted to `TINYINT' (a lossy conversion), but not a `TINYINT' column to an `INT' column (non-lossy). Attempting the latter conversion in this case would cause replication to stop with an error on the slave. `ALL_NON_LOSSY' This mode permits conversions that do not require truncation or other special handling of the source value; that is, it permits conversions where the source type has a wider range than the target type. Setting this mode has no bearing on whether lossy conversions are permitted; this is controlled with the `ALL_LOSSY' mode. If only `ALL_NON_LOSSY' is set, but not `ALL_LOSSY', then attempting a conversion that would result in the loss of data (such as `INT' to `TINYINT', or `CHAR(25)' to `VARCHAR(20)') causes the slave to stop with an error. `ALL_LOSSY,ALL_NON_LOSSY'When this mode is set, all supported type conversions are permitted, whether or not they are lossy conversions. [_empty_] When `slave_type_conversions' is not set, no attribute promotion or demotion is permitted; this means that all columns in the source and target tables must be of the same types. This mode is the default. Changing the type conversion mode requires restarting the slave with the new `slave_type_conversions' setting. Supported conversions Supported conversions between different but similar data types are shown in the following list: * Between any of the integer types *Note `TINYINT': numeric-types, *Note `SMALLINT': numeric-types, *Note `MEDIUMINT': numeric-types, *Note `INT': numeric-types, and *Note `BIGINT': numeric-types. This includes conversions between the signed and unsigned versions of these types. Lossy conversions are made by truncating the source value to the maximum (or minimum) permitted by the target column. For insuring non-lossy conversions when going from unsigned to signed types, the target column must be large enough to accommodate the range of values in the source column. For example, you can demote `TINYINT UNSIGNED' non-lossily to `SMALLINT', but not to `TINYINT'. * Between any of the decimal types *Note `DECIMAL': numeric-types, *Note `FLOAT': numeric-types, *Note `DOUBLE': numeric-types, and *Note `NUMERIC': numeric-types. `FLOAT' to `DOUBLE' is a non-lossy conversion; `DOUBLE' to `FLOAT' can only be handled lossily. A conversion from `DECIMAL(M,D)' to `DECIMAL(M',D')' where `M' => M' and `D' => D' is non-lossy; for any case where `M' < M', `D' < D', or both, only a lossy conversion can be made. For any of the decimal types, if a value to be stored cannot be fit in the target type, the value is rounded down according to the rounding rules defined for the server elsewhere in the documentation. See *Note precision-math-rounding::, for information about how this is done for decimal types. * Between any of the string types *Note `CHAR': char, *Note `VARCHAR': char, and *Note `TEXT': blob, including conversions between different widths. Conversion of a `CHAR', `VARCHAR', or `TEXT' to a `CHAR', `VARCHAR', or `TEXT' column the same size or larger is never lossy. Lossy conversion is handled by inserting only the first N characters of the string on the slave, where N is the width of the target column. *Important*: Replication between columns using different character sets is not supported. * Between any of the binary data types *Note `BINARY': binary-varbinary, *Note `VARBINARY': binary-varbinary, and *Note `BLOB': blob, including conversions between different widths. Conversion of a `BINARY', `VARBINARY', or `BLOB' to a `BINARY', `VARBINARY', or `BLOB' column the same size or larger is never lossy. Lossy conversion is handled by inserting only the first N bytes of the string on the slave, where N is the width of the target column. * Between any 2 *Note `BIT': numeric-types. columns of any 2 sizes. When inserting a value from a `BIT(M)' column into a `BIT(M')' column, where `M' > M', the most significant bits of the `BIT(M')' columns are cleared (set to zero) and the M bits of the `BIT(M)' value are set as the least significant bits of the `BIT(M')' column. When inserting a value from a source `BIT(M)' column into a target `BIT(M')' column, where `M' < M', the maximum possible value for the `BIT(M')' column is assigned; in other words, an `all-set' value is assigned to the target column. Conversions between types not in the previous list are not permitted.  File: manual.info, Node: replication-features-directory, Next: replication-features-invoked, Prev: replication-features-differing-tables, Up: replication-features 16.4.1.10 Replication and `DIRECTORY' Table Options ................................................... If a `DATA DIRECTORY' or `INDEX DIRECTORY' table option is used in a *Note `CREATE TABLE': create-table. statement on the master server, the table option is also used on the slave. This can cause problems if no corresponding directory exists in the slave host file system or if it exists but is not accessible to the slave server. This can be overridden by using the `NO_DIR_IN_CREATE' server SQL mode on the slave, which causes the slave to ignore the `DATA DIRECTORY' and `INDEX DIRECTORY' table options when replicating *Note `CREATE TABLE': create-table. statements. The result is that `MyISAM' data and index files are created in the table's database directory. For more information, see *Note server-sql-mode::.  File: manual.info, Node: replication-features-invoked, Next: replication-features-floatvalues, Prev: replication-features-directory, Up: replication-features 16.4.1.11 Replication of Invoked Features ......................................... Replication of invoked features such as user-defined functions (UDFs) and stored programs (stored procedures and functions, triggers, and events) was re-implemented in MySQL 5.1.18 to provide the following characteristics: * The effects of the feature are always replicated. * The following statements are replicated using statement-based replication: * *Note `CREATE EVENT': create-event. * *Note `ALTER EVENT': alter-event. * *Note `DROP EVENT': drop-event. * *Note `CREATE PROCEDURE': create-procedure. * *Note `DROP PROCEDURE': drop-procedure. * *Note `CREATE FUNCTION': create-function. * *Note `DROP FUNCTION': drop-function. * *Note `CREATE TRIGGER': create-trigger. * *Note `DROP TRIGGER': drop-trigger. However, the _effects_ of features created, modified, or dropped using these statements are replicated using row-based replication. *Note*: Attempting to replicate invoked features using statement-based replication produces the warning `Statement may not be safe to log in statement format'. (Prior to MySQL 5.1.36, this was `Statement is not safe to log in statement format'; see Bug#42415.) For example, trying to replicate a UDF with statement-based replication generates this warning because it currently cannot be determined by the MySQL server whether the UDF is deterministic. If you are absolutely certain that the invoked feature's effects are deterministic, you can safely disregard such warnings. * In the case of *Note `CREATE EVENT': create-event. and *Note `ALTER EVENT': alter-event.: * The status of the event is set to `SLAVESIDE_DISABLED' on the slave regardless of the state specified (this does not apply to *Note `DROP EVENT': drop-event.). * The master on which the event was created is identified on the slave by its server ID. The `ORIGINATOR' column in *Note `INFORMATION_SCHEMA.EVENTS': events-table. and the `originator' column in `mysql.event' were added to these tables in MySQL 5.1.18 to store this information. See *Note events-table::, and *Note show-events::, for more information. * The feature implementation resides on the slave in a renewable state so that if the master fails, the slave can be used as the master without loss of event processing. To determine whether there are any scheduled events on a MySQL server that were created on a different server (that was acting as a replication master), query the *Note `INFORMATION_SCHEMA.EVENTS': events-table. table in a manner similar to what is shown here: SELECT EVENT_SCHEMA, EVENT_NAME FROM INFORMATION_SCHEMA.EVENTS WHERE STATUS = 'SLAVESIDE_DISABLED'; Alternatively, you can use the *Note `SHOW EVENTS': show-events. statement, like this: SHOW EVENTS WHERE STATUS = 'SLAVESIDE_DISABLED'; When promoting a replication slave having such events to a replication master, you must enable each event using *Note `ALTER EVENT EVENT_NAME ENABLED': alter-event, where EVENT_NAME is the name of the event. If more than one master was involved in creating events on this slave, and you wish to identify events that were created only on a given master having the server ID MASTER_ID, modify the previous query on the *Note `EVENTS': events-table. table to include the `ORIGINATOR' column, as shown here: SELECT EVENT_SCHEMA, EVENT_NAME, ORIGINATOR FROM INFORMATION_SCHEMA.EVENTS WHERE STATUS = 'SLAVESIDE_DISABLED' AND ORIGINATOR = 'MASTER_ID' You can employ `ORIGINATOR' with the *Note `SHOW EVENTS': show-events. statement in a similar fashion: SHOW EVENTS WHERE STATUS = 'SLAVESIDE_DISABLED' AND ORIGINATOR = 'MASTER_ID' Before enabling events that were replicated from the master, you should disable the MySQL Event Scheduler on the slave (using a statement such as `SET GLOBAL event_scheduler = OFF;'), run any necessary *Note `ALTER EVENT': alter-event. statements, restart the server, then re-enable the Event Scheduler on the slave afterward (using a statement such as `SET GLOBAL event_scheduler = ON;')- If you later demote the new master back to being a replication slave, you must disable manually all events enabled by the *Note `ALTER EVENT': alter-event. statements. You can do this by storing in a separate table the event names from the *Note `SELECT': select. statement shown previously, or using *Note `ALTER EVENT': alter-event. statements to rename the events with a common prefix such as `replicated_' to identify them. If you rename the events, then when demoting this server back to being a replication slave, you can identify the events by querying the *Note `EVENTS': events-table. table, as shown here: SELECT CONCAT(EVENT_SCHEMA, '.', EVENT_NAME) AS 'Db.Event' FROM INFORMATION_SCHEMA.EVENTS WHERE INSTR(EVENT_NAME, 'replicated_') = 1;  File: manual.info, Node: replication-features-floatvalues, Next: replication-features-flush, Prev: replication-features-invoked, Up: replication-features 16.4.1.12 Replication and Floating-Point Values ............................................... With statement-based replication, values are converted from decimal to binary. Because conversions between decimal and binary representations of them may be approximate, comparisons involving floating-point values are inexact. This is true for operations that use floating-point values explicitly, or that use values that are converted to floating-point implicitly. Comparisons of floating-point values might yield different results on master and slave servers due to differences in computer architecture, the compiler used to build MySQL, and so forth. See *Note type-conversion::, and *Note problems-with-float::.  File: manual.info, Node: replication-features-flush, Next: replication-features-functions, Prev: replication-features-floatvalues, Up: replication-features 16.4.1.13 Replication and `FLUSH' ................................. Some forms of the *Note `FLUSH': flush. statement are not logged because they could cause problems if replicated to a slave: *Note `FLUSH LOGS': flush, *Note `FLUSH MASTER': flush, *Note `FLUSH SLAVE': flush, and *Note `FLUSH TABLES WITH READ LOCK': flush. For a syntax example, see *Note flush::. The *Note `FLUSH TABLES': flush, *Note `ANALYZE TABLE': analyze-table, *Note `OPTIMIZE TABLE': optimize-table, and *Note `REPAIR TABLE': repair-table. statements are written to the binary log and thus replicated to slaves. This is not normally a problem because these statements do not modify table data. However, this behavior can cause difficulties under certain circumstances. If you replicate the privilege tables in the `mysql' database and update those tables directly without using *Note `GRANT': grant, you must issue a *Note `FLUSH PRIVILEGES': flush. on the slaves to put the new privileges into effect. In addition, if you use *Note `FLUSH TABLES': flush. when renaming a `MyISAM' table that is part of a `MERGE' table, you must issue *Note `FLUSH TABLES': flush. manually on the slaves. These statements are written to the binary log unless you specify `NO_WRITE_TO_BINLOG' or its alias `LOCAL'.  File: manual.info, Node: replication-features-functions, Next: replication-features-limit, Prev: replication-features-flush, Up: replication-features 16.4.1.14 Replication and System Functions .......................................... Certain functions do not replicate well under some conditions: * The `USER()', `CURRENT_USER()' (or `CURRENT_USER'), `UUID()', `VERSION()', `LOAD_FILE()', and `RAND()' functions are replicated without change and thus do not work reliably on the slave unless row-based replication is enabled. (See *Note replication-formats::.) For early implementations of mixed-format logging, stored functions, triggers, and views that use these functions in their body do not replicate reliably in mixed-format logging mode because the logging did not switch from statement-based to row-based format. For example, `INSERT INTO t SELECT FROM v', where `v' is a view that selects `UUID()' could cause problems. This limitation is lifted in MySQL 5.1.12. Beginning with MySQL 5.1.23, `USER()' and `CURRENT_USER()' are automatically replicated using row-based replication when using `MIXED' mode, and generate a warning in `STATEMENT' mode. (Bug#28086) Beginning with MySQL 5.1.42, the same is true for `VERSION()'. (Bug#47995) Beginning with MySQL 5.1.43, this is also true with regard to the `RAND()' function. (Bug#49222) * For `NOW()', the binary log includes the timestamp. This means that the value _as returned by the call to this function on the master_ is replicated to the slave. This can lead to a possibly unexpected result when replicating between MySQL servers in different time zones. Suppose that the master is located in New York, the slave is located in Stockholm, and both servers are using local time. Suppose further that, on the master, you create a table `mytable', perform an *Note `INSERT': insert. statement on this table, and then select from the table, as shown here: mysql> CREATE TABLE mytable (mycol TEXT); Query OK, 0 rows affected (0.06 sec) mysql> INSERT INTO mytable VALUES ( NOW() ); Query OK, 1 row affected (0.00 sec) mysql> SELECT * FROM mytable; +---------------------+ | mycol | +---------------------+ | 2009-09-01 12:00:00 | +---------------------+ 1 row in set (0.00 sec) Local time in Stockholm is 6 hours later than in New York; so, if you issue `SELECT NOW()' on the slave at that exact same instant, the value `2009-09-01 18:00:00' is returned. For this reason, if you select from the slave's copy of `mytable' after the *Note `CREATE TABLE': create-table. and *Note `INSERT': insert. statements just shown have been replicated, you might expect `mycol' to contain the value `2009-09-01 18:00:00'. However, this is not the case; when you select from the slave's copy of `mytable', you obtain exactly the same result as on the master: mysql> SELECT * FROM mytable; +---------------------+ | mycol | +---------------------+ | 2009-09-01 12:00:00 | +---------------------+ 1 row in set (0.00 sec) Unlike `NOW()', the `SYSDATE()' function is not replication-safe because it is not affected by `SET TIMESTAMP' statements in the binary log and is nondeterministic if statement-based logging is used. This is not a problem if row-based logging is used. An alternative is to use the `--sysdate-is-now' option to cause `SYSDATE()' to be an alias for `NOW()'. This must be done on the master and the slave to work correctly. In such cases, a warning is still issued by this function, but can safely be ignored as long as `--sysdate-is-now' is used on both the master and the slave. Beginning with MySQL 5.1.42, `SYSDATE()' is automatically replicated using row-based replication when using `MIXED' mode, and generates a warning in `STATEMENT' mode. (Bug#47995) See also *Note replication-features-timezone::. * _The following restriction applies to statement-based replication only, not to row-based replication._ The `GET_LOCK()', `RELEASE_LOCK()', `IS_FREE_LOCK()', and `IS_USED_LOCK()' functions that handle user-level locks are replicated without the slave knowing the concurrency context on the master. Therefore, these functions should not be used to insert into a master table because the content on the slave would differ. For example, do not issue a statement such as `INSERT INTO mytable VALUES(GET_LOCK(...))'. Beginning with MySQL 5.1.42, these functions are automatically replicated using row-based replication when using `MIXED' mode, and generate a warning in `STATEMENT' mode. (Bug#47995) As a workaround for the preceding limitations when statement-based replication is in effect, you can use the strategy of saving the problematic function result in a user variable and referring to the variable in a later statement. For example, the following single-row *Note `INSERT': insert. is problematic due to the reference to the `UUID()' function: INSERT INTO t VALUES(UUID()); To work around the problem, do this instead: SET @my_uuid = UUID(); INSERT INTO t VALUES(@my_uuid); That sequence of statements replicates because the value of `@my_uuid' is stored in the binary log as a user-variable event prior to the *Note `INSERT': insert. statement and is available for use in the *Note `INSERT': insert. The same idea applies to multiple-row inserts, but is more cumbersome to use. For a two-row insert, you can do this: SET @my_uuid1 = UUID(); @my_uuid2 = UUID(); INSERT INTO t VALUES(@my_uuid1),(@my_uuid2); However, if the number of rows is large or unknown, the workaround is difficult or impracticable. For example, you cannot convert the following statement to one in which a given individual user variable is associated with each row: INSERT INTO t2 SELECT UUID(), * FROM t1; Within a stored function, `RAND()' replicates correctly as long as it is invoked only once during the execution of the function. (You can consider the function execution timestamp and random number seed as implicit inputs that are identical on the master and slave.) The `FOUND_ROWS()' and `ROW_COUNT()' functions are not replicated reliably using statement-based replication. A workaround is to store the result of the function call in a user variable, and then use that in the *Note `INSERT': insert. statement. For example, if you wish to store the result in a table named `mytable', you might normally do so like this: SELECT SQL_CALC_FOUND_ROWS FROM mytable LIMIT 1; INSERT INTO mytable VALUES( FOUND_ROWS() ); However, if you are replicating `mytable', you should use `SELECT INTO', and then store the variable in the table, like this: SELECT SQL_CALC_FOUND_ROWS INTO @found_rows FROM mytable LIMIT 1; INSERT INTO mytable VALUES(@found_rows); In this way, the user variable is replicated as part of the context, and applied on the slave correctly. Beginning with MySQL 5.1.23, these functions are automatically replicated using row-based replication when using `MIXED' mode, and generate a warning in `STATEMENT' mode. (Bug#12092, Bug#30244)  File: manual.info, Node: replication-features-limit, Next: replication-features-load-data, Prev: replication-features-functions, Up: replication-features 16.4.1.15 Replication and `LIMIT' ................................. Statement-based replication of `LIMIT' clauses in *Note `DELETE': delete, *Note `UPDATE': update, and *Note `INSERT ... SELECT': insert-select. statements is unsafe since the order of the rows affected is not defined. (Such statements can be replicated correctly with statement-based replication only if they also contain an `ORDER BY' clause.) Beginning with MySQL 5.1.24, when such a statement is encountered: * When using `STATEMENT' mode, a warning that the statement is not safe for statement-based replication is now issued. Currently, when using `STATEMENT' mode, warnings are issued for DML statements containing `LIMIT' even when they also have an `ORDER BY' clause (and so are made deterministic). This is a known issue. (Bug#42851) * When using `MIXED' mode, the statement is now automatically replicated using row-based mode.  File: manual.info, Node: replication-features-load-data, Next: replication-features-logging, Prev: replication-features-limit, Up: replication-features 16.4.1.16 Replication and `LOAD DATA INFILE' ............................................ The *Note `LOAD DATA INFILE': load-data. statement was not always replicated correctly to a slave running MySQL 5.1.42 or earlier from a master running MySQL 4.0 or earlier. When using statement-based replication, the *Note `LOAD DATA INFILE': load-data. statement `CONCURRENT' option was not replicated. This issue was fixed in MySQL 5.1.43. This issue does not have any impact on `CONCURRENT' option handling when using row-based replication in MySQL 5.1 or later. (Bug#34628) In MySQL 5.1.50 and later, *Note `LOAD DATA INFILE': load-data. is considered unsafe (see *Note replication-rbr-safe-unsafe::). It causes a warning when using statement-based logging format, and is logged using row-based format when using mixed-format logging.  File: manual.info, Node: replication-features-logging, Next: replication-features-repair-table, Prev: replication-features-load-data, Up: replication-features 16.4.1.17 Replication and the Slow Query Log ............................................ Prior to MySQL 5.1.45, replication slaves did not write replicated queries to the slow query log, even if the same queries were written to the slow query log on the master. (Bug#23300)  File: manual.info, Node: replication-features-repair-table, Next: replication-features-shutdowns, Prev: replication-features-logging, Up: replication-features 16.4.1.18 Replication and `REPAIR TABLE' ........................................ When used on a corrupted or otherwise damaged table, it is possible for the *Note `REPAIR TABLE': repair-table. statement to delete rows that cannot be recovered. However, any such modifications of table data performed by this statement are not replicated, which can cause master and slave to lose synchronization. For this reason, in the event that a table on the master becomes damaged and you use *Note `REPAIR TABLE': repair-table. to repair it, you should first stop replication (if it is still running) before using *Note `REPAIR TABLE': repair-table, then afterward compare the master's and slave's copies of the table and be prepared to correct any discrepancies manually, before restarting replication.  File: manual.info, Node: replication-features-shutdowns, Next: replication-features-max-allowed-packet, Prev: replication-features-repair-table, Up: replication-features 16.4.1.19 Replication and Master or Slave Shutdowns ................................................... It is safe to shut down a master server and restart it later. When a slave loses its connection to the master, the slave tries to reconnect immediately and retries periodically if that fails. The default is to retry every 60 seconds. This may be changed with the *Note `CHANGE MASTER TO': change-master-to. statement or `--master-connect-retry' option. A slave also is able to deal with network connectivity outages. However, the slave notices the network outage only after receiving no data from the master for `slave_net_timeout' seconds. If your outages are short, you may want to decrease `slave_net_timeout'. See *Note server-system-variables::. An unclean shutdown (for example, a crash) on the master side can result in the master binary log having a final position less than the most recent position read by the slave, due to the master binary log file not being flushed. This can cause the slave not to be able to replicate when the master comes back up. Setting `sync_binlog=1' in the master `my.cnf' file helps to minimize this problem because it causes the master to flush its binary log more frequently. Shutting down a slave cleanly is safe because it keeps track of where it left off. However, be careful that the slave does not have temporary tables open; see *Note replication-features-temptables::. Unclean shutdowns might produce problems, especially if the disk cache was not flushed to disk before the problem occurred: * For transactions, the slave commits and then updates `relay-log.info'. If a crash occurs between these two operations, relay log processing will have proceeded further than the information file indicates and the slave will re-execute the events from the last transaction in the relay log after it has been restarted. * A similar problem can occur if the slave updates `relay-log.info' but the server host crashes before the write has been flushed to disk. Writes are not forced to disk because the server relies on the operating system to flush the file from time to time. The fault tolerance of your system for these types of problems is greatly increased if you have a good uninterruptible power supply.  File: manual.info, Node: replication-features-max-allowed-packet, Next: replication-features-memory, Prev: replication-features-shutdowns, Up: replication-features 16.4.1.20 Replication and `max_allowed_packet' .............................................. `max_allowed_packet' sets an upper limit on the size of any single message between the MySQL server and clients, including replication slaves. If you are replicating large column values (such as might be found in *Note `TEXT': blob. or *Note `BLOB': blob. columns) and `max_allowed_packet' is too small on the master, the master fails with an error, and the slave shuts down the I/O thread. If `max_allowed_packet' is too small on the slave, this also causes the slave to stop the I/O thread. Prior to MySQL 5.1.40, `Last_IO_Error' and `Last_IO_Errno' in the output of *Note `SHOW SLAVE STATUS': show-slave-status. were not set in the event that replication failed due to exceeding `max_allowed_packet' (Bug#42914). Row-based replication currently sends all columns and column values for updated rows from the master to the slave, including values of columns that were not actually changed by the update. This means that, when you are replicating large column values using row-based replication, you must take care to set `max_allowed_packet' large enough to accommodate the largest row in any table to be replicated, even if you are replicating updates only, or you are inserting only relatively small values.  File: manual.info, Node: replication-features-memory, Next: replication-features-temptables, Prev: replication-features-max-allowed-packet, Up: replication-features 16.4.1.21 Replication and `MEMORY' Tables ......................................... When a master server shuts down and restarts, its *Note `MEMORY': memory-storage-engine. tables become empty. To replicate this effect to slaves, the first time that the master uses a given *Note `MEMORY': memory-storage-engine. table after startup, it logs an event that notifies slaves that the table must to be emptied by writing a *Note `DELETE': delete. statement for that table to the binary log. When a slave server shuts down and restarts, its *Note `MEMORY': memory-storage-engine. tables become empty. This causes the slave to be out of synchrony with the master and may lead to other failures or cause the slave to stop: * Row-format updates and deletes received from the master may fail with `Can't find record in 'MEMORY_TABLE''. * Statements such as *Note `INSERT INTO ... SELECT FROM MEMORY_TABLE': insert-select. may insert a different set of rows on the master and slave. The safe way to restart a slave that is replicating *Note `MEMORY': memory-storage-engine. tables is to first drop or delete all rows from the *Note `MEMORY': memory-storage-engine. tables on the master and wait until those changes have replicated to the slave. Then it is safe to restart the slave. An alternative restart method may apply in some cases. When `binlog_format=ROW', you can prevent the slave from stopping if you set `slave_exec_mode=IDEMPOTENT' before you start the slave again. This allows the slave to continue to replicate, but its *Note `MEMORY': memory-storage-engine. tables will still be different from those on the master. This can be okay if the application logic is such that the contents of *Note `MEMORY': memory-storage-engine. tables can be safely lost (for example, if the *Note `MEMORY': memory-storage-engine. tables are used for caching). `slave_exec_mode=IDEMPOTENT' applies globally to all tables, so it may hide other replication errors in non-*Note `MEMORY': memory-storage-engine. tables. See *Note memory-storage-engine::, for more information about *Note `MEMORY': memory-storage-engine. tables.  File: manual.info, Node: replication-features-temptables, Next: replication-features-mysqldb, Prev: replication-features-memory, Up: replication-features 16.4.1.22 Replication and Temporary Tables .......................................... This section does not apply when row-based replication is in use because in that case temporary tables are not replicated. It does apply with mixed-format replication for statements involving temporary tables that can be logged safely using statement-based format. See *Note replication-rbr-usage::. Safe slave shutdown when using temporary tables Temporary tables are replicated except in the case where you stop the slave server (not just the slave threads) and you have replicated temporary tables that are open for use in updates that have not yet been executed on the slave. If you stop the slave server, the temporary tables needed by those updates are no longer available when the slave is restarted. To avoid this problem, do not shut down the slave while it has temporary tables open. Instead, use the following procedure: 1. Issue a `STOP SLAVE SQL_THREAD' statement. 2. Use *Note `SHOW STATUS': show-status. to check the value of the `Slave_open_temp_tables' variable. 3. If the value is not 0, restart the slave SQL thread with `START SLAVE SQL_THREAD' and repeat the procedure later. 4. When the value is 0, issue a *Note `mysqladmin shutdown': mysqladmin. command to stop the slave. Temporary tables and replication options By default, all temporary tables are replicated; this happens whether or not there are any matching `--replicate-do-db', `--replicate-do-table', or `--replicate-wild-do-table' options in effect. However, the `--replicate-ignore-table' and `--replicate-wild-ignore-table' options are honored for temporary tables. A recommended practice when using statement-based or mixed-format replication is to designate a prefix for exclusive use in naming temporary tables that you do not want replicated, then employ a `--replicate-wild-ignore-table' option to match that prefix. For example, you might give all such tables names beginning with `norep' (such as `norepmytable', `norepyourtable', and so on), then use `--replicate-wild-ignore-table=norep%' to prevent them from being replicated.  File: manual.info, Node: replication-features-mysqldb, Next: replication-features-optimizer, Prev: replication-features-temptables, Up: replication-features 16.4.1.23 Replication of the `mysql' System Database .................................................... MySQL 5.1.14 and later Data modification statements made to tables in the `mysql' database are replicated according to the value of `binlog_format'; if this value is `MIXED', these statement are replicated using the row-based format. However, statements that would normally update this information indirectly--such *Note `GRANT': grant, *Note `REVOKE': revoke, and statements manipulating triggers, stored routines, and views--are replicated to slaves using statement-based replication. MySQL 5.1.13 and earlier User privileges are replicated only if the `mysql' database is replicated. That is, the *Note `GRANT': grant, *Note `REVOKE': revoke, *Note `SET PASSWORD': set-password, *Note `CREATE USER': create-user, and *Note `DROP USER': drop-user. statements take effect on the slave only if the replication setup includes the `mysql' database.  File: manual.info, Node: replication-features-optimizer, Next: replication-features-reserved-words, Prev: replication-features-mysqldb, Up: replication-features 16.4.1.24 Replication and the Query Optimizer ............................................. It is possible for the data on the master and slave to become different if a statement is written in such a way that the data modification is nondeterministic; that is, left up the query optimizer. (In general, this is not a good practice, even outside of replication.) Examples of nondeterministic statements include *Note `DELETE': delete. or *Note `UPDATE': update. statements that use `LIMIT' with no `ORDER BY' clause; see *Note replication-features-limit::, for a detailed discussion of these.  File: manual.info, Node: replication-features-reserved-words, Next: replication-features-set-password, Prev: replication-features-optimizer, Up: replication-features 16.4.1.25 Replication and Reserved Words ........................................ You can encounter problems when you attempt to replicate from an older master to a newer slave and you make use of identifiers on the master that are reserved words in the newer MySQL version running on the slave. An example of this is using a table column named `current_user' on a 4.0 master that is replicating to a 4.1 or higher slave because `CURRENT_USER' is a reserved word beginning in MySQL 4.1. Replication can fail in such cases with Error 1064 `You have an error in your SQL syntax...', _even if a database or table named using the reserved word or a table having a column named using the reserved word is excluded from replication_. This is due to the fact that each SQL event must be parsed by the slave prior to execution, so that the slave knows which database object or objects would be affected; only after the event is parsed can the slave apply any filtering rules defined by `--replicate-do-db', `--replicate-do-table', `--replicate-ignore-db', and `--replicate-ignore-table'. To work around the problem of database, table, or column names on the master which would be regarded as reserved words by the slave, do one of the following: * Use one or more *Note `ALTER TABLE': alter-table. statements on the master to change the names of any database objects where these names would be considered reserved words on the slave, and change any SQL statements that use the old names to use the new names instead. * In any SQL statements using these database object names, write the names as quoted identifiers using backtick characters (``'). For listings of reserved words by MySQL version, see Reserved Words (http://dev.mysql.com/doc/mysqld-version-reference/en/mysqld-version-reference-optvar.html), in the `MySQL Server Version Reference'. For identifier quoting rules, see *Note identifiers::.  File: manual.info, Node: replication-features-set-password, Next: replication-features-slaveerrors, Prev: replication-features-reserved-words, Up: replication-features 16.4.1.26 `SET PASSWORD' and Row-Based Replication .................................................. Row-based replication of *Note `SET PASSWORD': set-password. statements from a MySQL 5.1 master to a MySQL 5.5 slave did not work correctly prior to MySQL 5.1.53 on the master and MySQL 5.5.7 on the slave (see Bug#57098, Bug#57357).  File: manual.info, Node: replication-features-slaveerrors, Next: replication-features-sql-mode, Prev: replication-features-set-password, Up: replication-features 16.4.1.27 Slave Errors During Replication ......................................... If a statement produces the same error (identical error code) on both the master and the slave, the error is logged, but replication continues. If a statement produces different errors on the master and the slave, the slave SQL thread terminates, and the slave writes a message to its error log and waits for the database administrator to decide what to do about the error. This includes the case that a statement produces an error on the master or the slave, but not both. To address the issue, connect to the slave manually and determine the cause of the problem. *Note `SHOW SLAVE STATUS': show-slave-status. is useful for this. Then fix the problem and run *Note `START SLAVE': start-slave. For example, you might need to create a nonexistent table before you can start the slave again. If this error code validation behavior is not desirable, some or all errors can be masked out (ignored) with the `--slave-skip-errors' option. For nontransactional storage engines such as `MyISAM', it is possible to have a statement that only partially updates a table and returns an error code. This can happen, for example, on a multiple-row insert that has one row violating a key constraint, or if a long update statement is killed after updating some of the rows. If that happens on the master, the slave expects execution of the statement to result in the same error code. If it does not, the slave SQL thread stops as described previously. If you are replicating between tables that use different storage engines on the master and slave, keep in mind that the same statement might produce a different error when run against one version of the table, but not the other, or might cause an error for one version of the table, but not the other. For example, since `MyISAM' ignores foreign key constraints, an *Note `INSERT': insert. or *Note `UPDATE': update. statement accessing an `InnoDB' table on the master might cause a foreign key violation but the same statement performed on a `MyISAM' version of the same table on the slave would produce no such error, causing replication to stop.  File: manual.info, Node: replication-features-sql-mode, Next: replication-features-timeout, Prev: replication-features-slaveerrors, Up: replication-features 16.4.1.28 Replication and Server SQL Mode ......................................... Using different server SQL mode settings on the master and the slave may cause the same *Note `INSERT': insert. statements to be handled differently on the master and the slave, leading the master and slave to diverge. For best results, you should always use the same server SQL mode on the master and on the slave. This advice applies whether you are using statement-based or row-based replication. If you are replicating partitioned tables, using different SQL modes on the master and the slave is likely to cause issues. At a minimum, this is likely to cause the distribution of data among partitions to be different in the master's and slave's copies of a given table. It may also cause inserts into partitioned tables that succeed on the master to fail on the slave. For more information, see *Note server-sql-mode::.  File: manual.info, Node: replication-features-timeout, Next: replication-features-timestamp, Prev: replication-features-sql-mode, Up: replication-features 16.4.1.29 Replication Retries and Timeouts .......................................... The global system variable `slave_transaction_retries' affects replication as follows: If the slave SQL thread fails to execute a transaction because of an `InnoDB' deadlock or because it exceeded the `InnoDB' `innodb_lock_wait_timeout' value, or the *Note `NDBCLUSTER': mysql-cluster. `TransactionDeadlockDetectionTimeout' or `TransactionInactiveTimeout' value, the slave automatically retries the transaction `slave_transaction_retries' times before stopping with an error. The default value is 10. The total retry count can be seen in the output of *Note `SHOW STATUS': show-status.; see *Note server-status-variables::.  File: manual.info, Node: replication-features-timestamp, Next: replication-features-timezone, Prev: replication-features-timeout, Up: replication-features 16.4.1.30 Replication and `TIMESTAMP' ..................................... Older versions of MySQL (prior to 4.1) differed significantly in several ways in their handling of the *Note `TIMESTAMP': datetime. data type from what is supported in MySQL versions 5.1 and newer; these include syntax extensions which are deprecated in MySQL 5.1, and that no longer supported in MySQL 5.5. This this can cause problems (including replication failures) when replicating between MySQL Server versions, if you are using columns that are defined using the old *Note `TIMESTAMP(N)': datetime. syntax. See *Note upgrading-from-previous-series::, for more information about the differences, how they can impact MySQL replication, and what you can do if you encounter such problems.  File: manual.info, Node: replication-features-timezone, Next: replication-features-transactions, Prev: replication-features-timestamp, Up: replication-features 16.4.1.31 Replication and Time Zones .................................... The same system time zone should be set for both master and slave. Otherwise, statements depending on the local time on the master are not replicated properly, such as statements that use the `NOW()' or `FROM_UNIXTIME()' functions. You can set the time zone in which MySQL server runs by using the `--timezone=TIMEZONE_NAME' option of the `mysqld_safe' script or by setting the `TZ' environment variable. See also *Note replication-features-functions::. If the master is MySQL 4.1 or earlier, both master and slave should also use the same default connection time zone. That is, the `--default-time-zone' parameter should have the same value for both master and slave. `CONVERT_TZ(...,...,@@session.time_zone)' is properly replicated only if both master and slave are running MySQL 5.0.4 or newer.  File: manual.info, Node: replication-features-transactions, Next: replication-features-triggers, Prev: replication-features-timezone, Up: replication-features 16.4.1.32 Replication and Transactions ...................................... Mixing transactional and nontransactional statements within the same transaction In general, you should avoid transactions that update both transactional and nontransactional tables in a replication environment. You should also avoid using any statement that accesses both transactional (or temporary) and nontransactional tables and writes to any of them. As of MySQL 5.1.44, the server uses these rules for binary logging: * If the initial statements in a transaction are nontransactional, they are written to the binary log immediately. The remaining statements in the transaction are cached and not written to the binary log until the transaction is committed. (If the transaction is rolled back, the cached statements are written to the binary log only if they make nontransactional changes that cannot be rolled back. Otherwise, they are discarded.) * For statement-based logging, logging of nontransactional statements is affected by the `binlog_direct_non_transactional_updates' system variable. When this variable is `OFF' (the default), logging is as just described. When this variable is `ON', logging occurs immediately for nontransactional statements occurring anywhere in the transaction (not just initial nontransactional statements). Other statements are kept in the transaction cache and logged when the transaction commits. `binlog_direct_non_transactional_updates' has no effect for row-format or mixed-format binary logging. Transactional, nontransactional, and mixed statements To apply those rules, the server considers a statement nontransactional if it changes only nontransactional tables, and transactional if it changes only transactional tables. A statement that changes both nontransactional and transactional tables is considered `mixed'. Mixed statements, like transactional statements, are cached and logged when the transaction commits. *Note*: A mixed statement is unrelated to mixed binary logging format. Before MySQL 5.1.44, the rules for binary logging are similar to those just described, except that there is no `binlog_direct_non_transactional_updates' system variable to affect logging of transactional statements. Thus, the server immediately logs only the initial nontransactional statements in a transaction and caches the rest until commit time. Before MySQL 5.1.31, the _effect_ of the rules differs because the definition of transactional statement is different: In these earlier versions, a statement is nontransactional if the first changes it makes change nontransactional tables, transactional if the first changes it makes change transactional tables. `First' applies in the sense that a statement may have several effects if it involves such things as triggers, stored functions, or multiple-table updates. A mixed statement that changes both nontransactional and transactional tables is handled as nontransactional or transactional depending on the type of changes it makes first. In situations where transactions mix updates to transactional and nontransactional tables, the order of statements in the binary log is correct, and all needed statements are written to the binary log even in case of a *Note `ROLLBACK': commit. However, when a second connection updates the nontransactional table before the first connection transaction is complete, statements can be logged out of order because the second connection update is written immediately after it is performed, regardless of the state of the transaction being performed by the first connection. Using different storage engines on master and slave It is possible to replicate transactional tables on the master using nontransactional tables on the slave. For example, you can replicate an `InnoDB' master table as a `MyISAM' slave table. However, if you do this, there are problems if the slave is stopped in the middle of a *Note `BEGIN': commit ... *Note `COMMIT': commit. block because the slave restarts at the beginning of the *Note `BEGIN': commit. block. Beginning with MySQL 5.1.48, it is also safe to replicate transactions from *Note `MyISAM': myisam-storage-engine. tables on the master to transactional tables--such as tables that use the *Note `InnoDB': innodb-storage-engine. storage engine--on the slave. In such cases (beginning with MySQL 5.1.48), an `AUTOCOMMIT=1' statement issued on the master is replicated, thus enforcing `AUTOCOMMIT' mode on the slave. When the storage engine type of the slave is nontransactional, transactions on the master that mix updates of transactional and nontransactional tables should be avoided because they can cause inconsistency of the data between the master transactional table and the slave nontransactional table. That is, such transactions can lead to master storage engine-specific behavior with the possible effect of replication going out of synchrony. MySQL does not issue a warning about this currently, so extra care should be taken when replicating transactional tables from the master to nontransactional tables on the slaves. Beginning with MySQL Cluster NDB 6.2.14 and MySQL 5.1.24, every transaction (including `autocommit' transactions) is recorded in the binary log as though it starts with a *Note `BEGIN': commit. statement, and ends with either a *Note `COMMIT': commit. or a *Note `ROLLBACK': commit. statement. However, this does _not_ apply to nontransactional changes; any statements affecting tables using a nontransactional storage engine such as *Note `MyISAM': myisam-storage-engine. are regarded for this purpose as nontransactional, even when `autocommit' is enabled. (Bug#26395)  File: manual.info, Node: replication-features-triggers, Next: replication-features-views, Prev: replication-features-transactions, Up: replication-features 16.4.1.33 Replication and Triggers .................................. With statement-based replication, triggers executed on the master also execute on the slave. With row-based replication, triggers executed on the master do not execute on the slave. Instead, the row changes on the master resulting from trigger execution are replicated and applied on the slave. This behavior is by design. If under row-based replication the slave applied the triggers as well as the row changes caused by them, the changes would in effect be applied twice on the slave, leading to different data on the master and the slave. If you want triggers to execute on both the master and the slave--perhaps because you have different triggers on the master and slave--you must use statement-based replication. However, to enable slave-side triggers, it is not necessary to use statement-based replication exclusively. It is sufficient to switch to statement-based replication only for those statements where you want this effect, and to use row-based replication the rest of the time. Before MySQL 5.1.31, a trigger that was defined on a transactional table but that updated a nontransactional table could cause updates on the transactional table to be replicated before they were actually committed on the master, and not be rolled back correctly on the slave if they were rolled back on the master. (Bug#40116) See also *Note replication-features-transactions::. A statement invoking a trigger (or function) that causes an update to an `AUTO_INCREMENT' column is not replicated correctly using statement-based replication. Beginning with MySQL 5.1.40, such statements are marked as unsafe. (Bug#45677)  File: manual.info, Node: replication-features-views, Next: replication-features-truncate, Prev: replication-features-triggers, Up: replication-features 16.4.1.34 Replication and Views ............................... Views are always replicated to slaves. Views are filtered by their own name, not by the tables they refer to. This means that a view can be replicated to the slave even if the view contains a table that would normally be filtered out by `replication-ignore-table' rules. Care should therefore be taken to ensure that views do not replicate table data that would normally be filtered for security reasons.  File: manual.info, Node: replication-features-truncate, Next: replication-features-variables, Prev: replication-features-views, Up: replication-features 16.4.1.35 Replication and `TRUNCATE TABLE' .......................................... *Note `TRUNCATE TABLE': truncate-table. is normally regarded as a DML statement, and so would be expected to be logged and replicated using row-based format when the binary logging mode is `ROW' or `MIXED'. However this caused issues when logging or replicating, in `STATEMENT' or `MIXED' mode, tables that used transactional storage engines such as *Note `InnoDB': innodb-storage-engine. when the transaction isolation level was `READ COMMITTED' or `READ UNCOMMITTED', which precludes statement-based logging. Beginning with MySQL 5.1.32, *Note `TRUNCATE TABLE': truncate-table. is treated for purposes of logging and replication as DDL rather than DML so that it can be logged and replicated as a statement. However, the effects of the statement as applicable to *Note `InnoDB': innodb-storage-engine. and other transactional tables on replication slaves still follow the rules described in *Note truncate-table:: governing such tables. (Bug#36763)  File: manual.info, Node: replication-features-variables, Prev: replication-features-truncate, Up: replication-features 16.4.1.36 Replication and Variables ................................... System variables are not replicated correctly when using `STATEMENT' mode, except for the following variables when they are used with session scope: * `auto_increment_increment' * `auto_increment_offset' * `character_set_client' * `character_set_connection' * `character_set_database' * `character_set_server' * `collation_connection' * `collation_database' * `collation_server' * `foreign_key_checks' * `identity' * `last_insert_id' * `lc_time_names' * `pseudo_thread_id' * `sql_auto_is_null' * `time_zone' * `timestamp' * `unique_checks' When `MIXED' mode is used, the variables in the preceding list, when used with session scope, cause a switch from statement-based to row-based logging. See *Note binary-log-mixed::. `sql_mode' is also replicated except for the `NO_DIR_IN_CREATE' mode; the slave always preserves its own value for `NO_DIR_IN_CREATE', regardless of changes to it on the master. This is true for all replication formats. However, when *Note `mysqlbinlog': mysqlbinlog. parses a `SET @@sql_mode = MODE' statement, the full MODE value, including `NO_DIR_IN_CREATE', is passed to the receiving server. For this reason, replication of such a statement may not be safe when `STATEMENT' mode is in use. The `storage_engine' system variable is not replicated, regardless of the logging mode; this is intended to facilitate replication between different storage engines. The `read_only' system variable is not replicated. In addition, the enabling this variable has different effects with regard to temporary tables, table locking, and the *Note `SET PASSWORD': set-password. statement in different MySQL versions. In statement-based replication, session variables are not replicated properly when used in statements that update tables. For example, the following sequence of statements will not insert the same data on the master and the slave: SET max_join_size=1000; INSERT INTO mytable VALUES(@@max_join_size); This does not apply to the common sequence: SET time_zone=...; INSERT INTO mytable VALUES(CONVERT_TZ(..., ..., @@time_zone)); Replication of session variables is not a problem when row-based replication is being used, in which case, session variables are always replicated safely. See *Note replication-formats::. In MySQL 5.1.20 and later (and in MySQL 5.0.46 and later in MySQL 5.0, for backward compatibility), the following session variables are written to the binary log and honored by the replication slave when parsing the binary log, regardless of the logging format: * `sql_mode' * `foreign_key_checks' * `unique_checks' * `character_set_client' * `collation_connection' * `collation_database' * `collation_server' * `sql_auto_is_null' *Important*: Even though session variables relating to character sets and collations are written to the binary log, replication between different character sets is not supported. It is strongly recommended that you always use the same setting for the `lower_case_table_names' system variable on both master and slave. In particular, when a case-sensitive file system is used, setting this variable to 1 on the slave, but to a different value on the master, can cause two types of problems: Names of databases are not converted to lowercase; in addition, when using row-based replication names of tables are also not converted. Either of these problems can cause replication to fail. This is a known issue, which is fixed in MySQL 5.6.  File: manual.info, Node: replication-compatibility, Next: replication-upgrade, Prev: replication-features, Up: replication-notes 16.4.2 Replication Compatibility Between MySQL Versions ------------------------------------------------------- MySQL supports replication from one major version to the next higher major version. For example, you can replicate from a master running MySQL 4.1 to a slave running MySQL 5.0, from a master running MySQL 5.0 to a slave running MySQL 5.1, and so on. However, one may encounter difficulties when replicating from an older master to a newer slave if the master uses statements or relies on behavior no longer supported in the version of MySQL used on the slave. The use of more than 2 MySQL Server versions is not supported in replication setups involving multiple masters, regardless of the number of master or slave MySQL servers. This restriction applies not only to major versions, but to minor versions within the same major version as well. For example, if you are using a chained or circular replication setup, you cannot use MySQL 5.1.31, MySQL 5.1.32, and MySQL 5.1.34 concurrently, although you could use any 2 of these releases together. In some cases, it is also possible to replicate between a master and a slave that is more than one major version newer than the master. However, there are known issues with trying to replicate from a master running MySQL 4.1 or earlier to a slave running MySQL 5.1 or later. To work around such problems, you can insert a MySQL server running an intermediate version between the two; for example, rather than replicating directly from a MySQL 4.1 master to a MySQL 5.1 slave, it is possible to replicate from a MySQL 4.1 server to a MySQL 5.0 server, and then from the MySQL 5.0 server to a MySQL 5.1 server. *Important*: It is strongly recommended to use the most recent release available within a given MySQL major version because replication (and other) capabilities are continually being improved. It is also recommended to upgrade masters and slaves that use early releases of a major version of MySQL to GA (production) releases when the latter become available for that major version. Replication from newer masters to older slaves may be possible, but is generally not supported. This is due to a number of factors: * Binary log format changes The binary log format can change between major releases. While we attempt to maintain backward compatibility, this is not always possible. For example, the binary log format implemented in MySQL 5.0 changed considerably from that used in previous versions, especially with regard to handling of character sets, *Note `LOAD DATA INFILE': load-data, and time zones. This means that replication from a MySQL 5.0 (or later) master to a MySQL 4.1 (or earlier) slave is generally not supported. This also has significant implications for upgrading replication servers; see *Note replication-upgrade::, for more information. * Use of row-based replication Row-based replication was implemented in MySQL 5.1.5, so you cannot replicate using row-based replication from any MySQL 5.1 or later master to a slave older than MySQL 5.1.5. For more information about row-based replication, see *Note replication-formats::. * SQL incompatibilities You cannot replicate from a newer master to an older slave using statement-based replication if the statements to be replicated use SQL features available on the master but not on the slave. However, if both the master and the slave support row-based replication, and there are no data definition statements to be replicated that depend on SQL features found on the master but not on the slave, you can use row-based replication to replicate the effects of data modification statements even if the DDL run on the master is not supported on the slave. For more information on potential replication issues, see *Note replication-features::.  File: manual.info, Node: replication-upgrade, Next: replication-faq, Prev: replication-compatibility, Up: replication-notes 16.4.3 Upgrading a Replication Setup ------------------------------------ When you upgrade servers that participate in a replication setup, the procedure for upgrading depends on the current server versions and the version to which you are upgrading. This section applies to upgrading replication from older versions of MySQL to MySQL 5.1. A 4.0 server should be 4.0.3 or newer. When you upgrade a master to 5.1 from an earlier MySQL release series, you should first ensure that all the slaves of this master are using the same 5.1.x release. If this is not the case, you should first upgrade the slaves. To upgrade each slave, shut it down, upgrade it to the appropriate 5.1.x version, restart it, and restart replication. The 5.1 slave is able to read the old relay logs written prior to the upgrade and to execute the statements they contain. Relay logs created by the slave after the upgrade are in 5.1 format. After the slaves have been upgraded, shut down the master, upgrade it to the same 5.1.x release as the slaves, and restart it. The 5.1 master is able to read the old binary logs written prior to the upgrade and to send them to the 5.1 slaves. The slaves recognize the old format and handle it properly. Binary logs created by the master subsequent to the upgrade are in 5.1 format. These too are recognized by the 5.1 slaves. In other words, when upgrading to MySQL 5.1, the slaves must be MySQL 5.1 before you can upgrade the master to 5.1. Note that downgrading from 5.1 to older versions does not work so simply: You must ensure that any 5.1 binary log or relay log has been fully processed, so that you can remove it before proceeding with the downgrade. Downgrading a replication setup to a previous version cannot be done once you have switched from statement-based to row-based replication, and after the first row-based statement has been written to the binlog. See *Note replication-formats::. Some upgrades may require that you drop and re-create database objects when you move from one MySQL series to the next. For example, collation changes might require that table indexes be rebuilt. Such operations, if necessary, will be detailed at *Note upgrading-from-previous-series::. It is safest to perform these operations separately on the slaves and the master, and to disable replication of these operations from the master to the slave. To achieve this, use the following procedure: 1. Stop all the slaves and upgrade them. Restart them with the `--skip-slave-start' option so that they do not connect to the master. Perform any table repair or rebuilding operations needed to re-create database objects, such as use of `REPAIR TABLE' or `ALTER TABLE', or dumping and reloading tables or triggers. 2. Disable the binary log on the master. To do this without restarting the master, execute a `SET sql_log_bin = 0' statement. Alternatively, stop the master and restart it without the `--log-bin' option. If you restart the master, you might also want to disallow client connections. For example, if all clients connect using TCP/IP, use the `--skip-networking' option when you restart the master. 3. With the binary log disabled, perform any table repair or rebuilding operations needed to re-create database objects. The binary log must be disabled during this step to prevent these operations from being logged and sent to the slaves later. 4. Re-enable the binary log on the master. If you set `sql_log_bin' to 0 earlier, execute a `SET sql_log_bin = 1' statement. If you restarted the master to disable the binary log, restart it with `--log-bin', and without `--skip-networking' so that clients and slaves can connect. 5. Restart the slaves, this time without the `--skip-slave-start' option.  File: manual.info, Node: replication-faq, Next: replication-problems, Prev: replication-upgrade, Up: replication-notes 16.4.4 Replication FAQ ---------------------- *Questions* * 16.4.4.1: Must the slave be connected to the master all the time? * 16.4.4.2: Must I enable networking on my master and slave to enable replication? * 16.4.4.3: How do I know how late a slave is compared to the master? In other words, how do I know the date of the last statement replicated by the slave? * 16.4.4.4: How do I force the master to block updates until the slave catches up? * 16.4.4.5: What issues should I be aware of when setting up two-way replication? * 16.4.4.6: How can I use replication to improve performance of my system? * 16.4.4.7: What should I do to prepare client code in my own applications to use performance-enhancing replication? * 16.4.4.8: When and how much can MySQL replication improve the performance of my system? * 16.4.4.9: How can I use replication to provide redundancy or high availability? * 16.4.4.10: How do I tell whether a master server is using statement-based or row-based binary logging format? * 16.4.4.11: How do I tell a slave to use row-based replication? * 16.4.4.12: How do I prevent *Note `GRANT': grant. and *Note `REVOKE': revoke. statements from replicating to slave machines? * 16.4.4.13: Does replication work on mixed operating systems (for example, the master runs on Linux while slaves run on Mac OS X and Windows)? * 16.4.4.14: Does replication work on mixed hardware architectures (for example, the master runs on a 64-bit machine while slaves run on 32-bit machines)? *Questions and Answers* *16.4.4.1: ** Must the slave be connected to the master all the time? * No, it does not. The slave can go down or stay disconnected for hours or even days, and then reconnect and catch up on updates. For example, you can set up a master/slave relationship over a dial-up link where the link is up only sporadically and for short periods of time. The implication of this is that, at any given time, the slave is not guaranteed to be in synchrony with the master unless you take some special measures. To ensure that catchup can occur for a slave that has been disconnected, you must not remove binary log files from the master that contain information that has not yet been replicated to the slaves. Asynchronous replication can work only if the slave is able to continue reading the binary log from the point where it last read events. *16.4.4.2: ** Must I enable networking on my master and slave to enable replication? * Yes, networking must be enabled on the master and slave. If networking is not enabled, the slave cannot connect to the master and transfer the binary log. Check that the `skip-networking' option has not been enabled in the configuration file for either server. *16.4.4.3: ** How do I know how late a slave is compared to the master? In other words, how do I know the date of the last statement replicated by the slave? * Check the `Seconds_Behind_Master' column in the output from *Note `SHOW SLAVE STATUS': show-slave-status. See *Note replication-administration-status::. When the slave SQL thread executes an event read from the master, it modifies its own time to the event timestamp. (This is why *Note `TIMESTAMP': datetime. is well replicated.) In the `Time' column in the output of *Note `SHOW PROCESSLIST': show-processlist, the number of seconds displayed for the slave SQL thread is the number of seconds between the timestamp of the last replicated event and the real time of the slave machine. You can use this to determine the date of the last replicated event. Note that if your slave has been disconnected from the master for one hour, and then reconnects, you may immediately see large `Time' values such as 3600 for the slave SQL thread in *Note `SHOW PROCESSLIST': show-processlist. This is because the slave is executing statements that are one hour old. See *Note replication-implementation-details::. *16.4.4.4: ** How do I force the master to block updates until the slave catches up? * Use the following procedure: 1. On the master, execute these statements: mysql> FLUSH TABLES WITH READ LOCK; mysql> SHOW MASTER STATUS; Record the replication coordinates (the current binary log file name and position) from the output of the *Note `SHOW': show. statement. 2. On the slave, issue the following statement, where the arguments to the `MASTER_POS_WAIT()' function are the replication coordinate values obtained in the previous step: mysql> SELECT MASTER_POS_WAIT('LOG_NAME', LOG_POS); The *Note `SELECT': select. statement blocks until the slave reaches the specified log file and position. At that point, the slave is in synchrony with the master and the statement returns. 3. On the master, issue the following statement to enable the master to begin processing updates again: mysql> UNLOCK TABLES; *16.4.4.5: ** What issues should I be aware of when setting up two-way replication? * MySQL replication currently does not support any locking protocol between master and slave to guarantee the atomicity of a distributed (cross-server) update. In other words, it is possible for client A to make an update to co-master 1, and in the meantime, before it propagates to co-master 2, client B could make an update to co-master 2 that makes the update of client A work differently than it did on co-master 1. Thus, when the update of client A makes it to co-master 2, it produces tables that are different from what you have on co-master 1, even after all the updates from co-master 2 have also propagated. This means that you should not chain two servers together in a two-way replication relationship unless you are sure that your updates can safely happen in any order, or unless you take care of mis-ordered updates somehow in the client code. You should also realize that two-way replication actually does not improve performance very much (if at all) as far as updates are concerned. Each server must do the same number of updates, just as you would have a single server do. The only difference is that there is a little less lock contention because the updates originating on another server are serialized in one slave thread. Even this benefit might be offset by network delays. *16.4.4.6: ** ** ** How can I use replication to improve performance of my system? * Set up one server as the master and direct all writes to it. Then configure as many slaves as you have the budget and rackspace for, and distribute the reads among the master and the slaves. You can also start the slaves with the `--skip-innodb', `--low-priority-updates', and `--delay-key-write=ALL' options to get speed improvements on the slave end. In this case, the slave uses nontransactional `MyISAM' tables instead of `InnoDB' tables to get more speed by eliminating transactional overhead. *16.4.4.7: ** What should I do to prepare client code in my own applications to use performance-enhancing replication? * See the guide to using replication as a scale-out solution, *Note replication-solutions-scaleout::. *16.4.4.8: ** When and how much can MySQL replication improve the performance of my system? * MySQL replication is most beneficial for a system that processes frequent reads and infrequent writes. In theory, by using a single-master/multiple-slave setup, you can scale the system by adding more slaves until you either run out of network bandwidth, or your update load grows to the point that the master cannot handle it. To determine how many slaves you can use before the added benefits begin to level out, and how much you can improve performance of your site, you must know your query patterns, and determine empirically by benchmarking the relationship between the throughput for reads and writes on a typical master and a typical slave. The example here shows a rather simplified calculation of what you can get with replication for a hypothetical system. Let `reads' and `writes' denote the number of reads and writes per second, respectively. Let's say that system load consists of 10% writes and 90% reads, and we have determined by benchmarking that `reads' is 1200 - 2 x `writes'. In other words, the system can do 1,200 reads per second with no writes, the average write is twice as slow as the average read, and the relationship is linear. Suppose that the master and each slave have the same capacity, and that we have one master and N slaves. Then we have for each server (master or slave): `reads' = 1200 - 2 x `writes' `reads' = 9 x `writes' / (N + 1) (reads are split, but writes replicated to all slaves) 9 x `writes' / (N + 1) + 2 x `writes' = 1200 `writes' = 1200 / (2 + 9/(N + 1)) The last equation indicates the maximum number of writes for N slaves, given a maximum possible read rate of 1,200 per minute and a ratio of nine reads per write. This analysis yields the following conclusions: * If N = 0 (which means we have no replication), our system can handle about 1200/11 = 109 writes per second. * If N = 1, we get up to 184 writes per second. * If N = 8, we get up to 400 writes per second. * If N = 17, we get up to 480 writes per second. * Eventually, as N approaches infinity (and our budget negative infinity), we can get very close to 600 writes per second, increasing system throughput about 5.5 times. However, with only eight servers, we increase it nearly four times. Note that these computations assume infinite network bandwidth and neglect several other factors that could be significant on your system. In many cases, you may not be able to perform a computation similar to the one just shown that accurately predicts what will happen on your system if you add N replication slaves. However, answering the following questions should help you decide whether and by how much replication will improve the performance of your system: * What is the read/write ratio on your system? * How much more write load can one server handle if you reduce the reads? * For how many slaves do you have bandwidth available on your network? *16.4.4.9: ** How can I use replication to provide redundancy or high availability? * How you implement redundancy is entirely dependent on your application and circumstances. High-availability solutions (with automatic failover) require active monitoring and either custom scripts or third party tools to provide the failover support from the original MySQL server to the slave. To handle the process manually, you should be able to switch from a failed master to a pre-configured slave by altering your application to talk to the new server or by adjusting the DNS for the MySQL server from the failed server to the new server. For more information and some example solutions, see *Note replication-solutions-switch::. *16.4.4.10: ** How do I tell whether a master server is using statement-based or row-based binary logging format? * Check the value of the `binlog_format' system variable: mysql> SHOW VARIABLES LIKE 'binlog_format'; The value shown will be one of `STATEMENT', `ROW', or `MIXED'. For `MIXED' mode, row-based logging is preferred but replication switches automatically to statement-based logging under certain conditions; for information about when this may occur, see *Note binary-log-mixed::. *16.4.4.11: ** How do I tell a slave to use row-based replication? * Slaves automatically know which format to use. *16.4.4.12: ** How do I prevent *Note `GRANT': grant. and *Note `REVOKE': revoke. statements from replicating to slave machines? * Start the server with the `--replicate-wild-ignore-table=mysql.%' option to ignore replication for tables in the `mysql' database. *16.4.4.13: ** Does replication work on mixed operating systems (for example, the master runs on Linux while slaves run on Mac OS X and Windows)? * Yes. *16.4.4.14: ** Does replication work on mixed hardware architectures (for example, the master runs on a 64-bit machine while slaves run on 32-bit machines)? * Yes.  File: manual.info, Node: replication-problems, Next: replication-bugs, Prev: replication-faq, Up: replication-notes 16.4.5 Troubleshooting Replication ---------------------------------- If you have followed the instructions but your replication setup is not working, the first thing to do is _check the error log for messages_. Many users have lost time by not doing this soon enough after encountering problems. If you cannot tell from the error log what the problem was, try the following techniques: * Verify that the master has binary logging enabled by issuing a *Note `SHOW MASTER STATUS': show-master-status. statement. If logging is enabled, `Position' is nonzero. If binary logging is not enabled, verify that you are running the master with the `--log-bin' option. * Verify that the master and slave both were started with the `--server-id' option and that the ID value is unique on each server. * Verify that the slave is running. Use *Note `SHOW SLAVE STATUS': show-slave-status. to check whether the `Slave_IO_Running' and `Slave_SQL_Running' values are both `Yes'. If not, verify the options that were used when starting the slave server. For example, `--skip-slave-start' prevents the slave threads from starting until you issue a *Note `START SLAVE': start-slave. statement. * If the slave is running, check whether it established a connection to the master. Use *Note `SHOW PROCESSLIST': show-processlist, find the I/O and SQL threads and check their `State' column to see what they display. See *Note replication-implementation-details::. If the I/O thread state says `Connecting to master', check the following: * Verify the privileges for the user being used for replication on the master. * Check that the host name of the master is correct and that you are using the correct port to connect to the master. The port used for replication is the same as used for client network communication (the default is `3306'). For the host name, ensure that the name resolves to the correct IP address. * Check that networking has not been disabled on the master or slave. Look for the `skip-networking' option in the configuration file. If present, comment it out or remove it. * If the master has a firewall or IP filtering configuration, ensure that the network port being used for MySQL is not being filtered. * Check that you can reach the master by using `ping' or `traceroute'/`tracert' to reach the host. * If the slave was running previously but has stopped, the reason usually is that some statement that succeeded on the master failed on the slave. This should never happen if you have taken a proper snapshot of the master, and never modified the data on the slave outside of the slave thread. If the slave stops unexpectedly, it is a bug or you have encountered one of the known replication limitations described in *Note replication-features::. If it is a bug, see *Note replication-bugs::, for instructions on how to report it. * If a statement that succeeded on the master refuses to run on the slave, try the following procedure if it is not feasible to do a full database resynchronization by deleting the slave's databases and copying a new snapshot from the master: 1. Determine whether the affected table on the slave is different from the master table. Try to understand how this happened. Then make the slave's table identical to the master's and run *Note `START SLAVE': start-slave. 2. If the preceding step does not work or does not apply, try to understand whether it would be safe to make the update manually (if needed) and then ignore the next statement from the master. 3. If you decide that the slave can skip the next statement from the master, issue the following statements: mysql> SET GLOBAL sql_slave_skip_counter = N; mysql> START SLAVE; The value of N should be 1 if the next statement from the master does not use `AUTO_INCREMENT' or `LAST_INSERT_ID()'. Otherwise, the value should be 2. The reason for using a value of 2 for statements that use `AUTO_INCREMENT' or `LAST_INSERT_ID()' is that they take two events in the binary log of the master. See also *Note set-global-sql-slave-skip-counter::. 4. If you are sure that the slave started out perfectly synchronized with the master, and that no one has updated the tables involved outside of the slave thread, then presumably the discrepancy is the result of a bug. If you are running the most recent version of MySQL, please report the problem. If you are running an older version, try upgrading to the latest production release to determine whether the problem persists.  File: manual.info, Node: replication-bugs, Prev: replication-problems, Up: replication-notes 16.4.6 How to Report Replication Bugs or Problems ------------------------------------------------- When you have determined that there is no user error involved, and replication still either does not work at all or is unstable, it is time to send us a bug report. We need to obtain as much information as possible from you to be able to track down the bug. Please spend some time and effort in preparing a good bug report. If you have a repeatable test case that demonstrates the bug, please enter it into our bugs database using the instructions given in *Note bug-reports::. If you have a `phantom' problem (one that you cannot duplicate at will), use the following procedure: 1. Verify that no user error is involved. For example, if you update the slave outside of the slave thread, the data goes out of synchrony, and you can have unique key violations on updates. In this case, the slave thread stops and waits for you to clean up the tables manually to bring them into synchrony. _This is not a replication problem. It is a problem of outside interference causing replication to fail._ 2. Run the slave with the `--log-slave-updates' and `--log-bin' options. These options cause the slave to log the updates that it receives from the master into its own binary logs. 3. Save all evidence before resetting the replication state. If we have no information or only sketchy information, it becomes difficult or impossible for us to track down the problem. The evidence you should collect is: * All binary log files from the master * All binary log files from the slave * The output of *Note `SHOW MASTER STATUS': show-master-status. from the master at the time you discovered the problem * The output of *Note `SHOW SLAVE STATUS': show-slave-status. from the slave at the time you discovered the problem * Error logs from the master and the slave 4. Use *Note `mysqlbinlog': mysqlbinlog. to examine the binary logs. The following should be helpful to find the problem statement. LOG_FILE and LOG_POS are the `Master_Log_File' and `Read_Master_Log_Pos' values from *Note `SHOW SLAVE STATUS': show-slave-status. shell> mysqlbinlog --start-position=LOG_POS LOG_FILE | head After you have collected the evidence for the problem, try to isolate it as a separate test case first. Then enter the problem with as much information as possible into our bugs database using the instructions at *Note bug-reports::.  File: manual.info, Node: mysql-cluster, Next: partitioning, Prev: replication, Up: Top 17 MySQL Cluster NDB 6.X/7.X **************************** * Menu: * mysql-cluster-overview:: MySQL Cluster Overview * mysql-cluster-installation:: MySQL Cluster Installation * mysql-cluster-configuration:: MySQL Cluster Configuration * mysql-cluster-programs:: MySQL Cluster Programs * mysql-cluster-management:: Management of MySQL Cluster * mysql-cluster-replication:: MySQL Cluster Replication * mysql-cluster-news:: Changes in MySQL Cluster NDB 6.X and 7.X This chapter contains information about _MySQL Cluster_, which is a high-availability, high-redundancy version of MySQL adapted for the distributed computing environment. Current releases of MySQL Cluster use versions 6 and 7 of the *Note `NDBCLUSTER': mysql-cluster. storage engine (also known as *Note `NDB': mysql-cluster.) to enable running several computers with MySQL servers and other software in a cluster. Beginning with MySQL 5.1.24, support for the *Note `NDBCLUSTER': mysql-cluster. storage engine was removed from the standard MySQL server binaries built by MySQL. Instead, users of MySQL Cluster binaries built by MySQL should upgrade to the most recent binary release of MySQL Cluster NDB 7.0 or MySQL Cluster 7.1 for supported platforms--these include RPMs that should work with most Linux distributions. MySQL Cluster users who build from source should be aware that, also beginning with MySQL 5.1.24, *Note `NDBCLUSTER': mysql-cluster. sources in the standard MySQL 5.1 tree are no longer maintained; these users should use the sources provided for MySQL Cluster NDB 7.0 or later. (Locations where the sources can be obtained are listed later in this section.) *Note*: MySQL Cluster NDB 6.1, 6.2, and 6.3 were formerly known as `MySQL Cluster Carrier Grade Edition'. Beginning with MySQL Cluster NDB 6.2.15 and MySQL Cluster NDB 6.3.14, this term is no longer applied to the MySQL Cluster software--which is now known simply as `MySQL Cluster'--but rather to a commercial licensing and support package. You can learn more about available options for commercial licensing of MySQL Cluster from http://mysql.com/products/database/cluster/features.html, on the MySQL web site. This chapter contains information about MySQL Cluster in MySQL 5.1 mainline releases through MySQL 5.1.23, MySQL Cluster NDB 6.2 releases through 5.1.51-ndb-6.2.19, MySQL Cluster NDB 6.3 releases through 5.1.56-ndb-6.3.45, MySQL Cluster NDB 7.0 releases through 5.1.56-ndb-7.0.27 and MySQL Cluster NDB 7.1 releases through 5.1.56-ndb-7.1.16. Currently, the MySQL Cluster NDB 7.0 (formerly known as `MySQL Cluster NDB 6.4') and MySQL Cluster NDB 7.1 release series are Generally Available (GA). MySQL Cluster NDB 6.2 and MySQL Cluster NDB 6.3 are previous GA release series; although these are still supported, we recommend that new deployments use MySQL Cluster NDB 7.0 or MySQL Cluster NDB 7.1. This chapter also contains historical information about MySQL Cluster NDB 6.1, although this release series is no longer in active development, and no longer supported for new deployments. You should upgrade to MySQL Cluster 6.3 or a MySQL Cluster NDB 7.x release series as soon as possible. Supported Platforms MySQL Cluster is currently available and supported on a number of platforms. For exact levels of support available for on specific combinations of operating system versions, operating system distributions, and hardware platforms, please refer to http://www.mysql.com/support/supportedplatforms/cluster.html. Availability MySQL Cluster NDB 6.3, MySQL Cluster NDB 7.0, and MySQL Cluster NDB 7.1 binary and source packages are available for supported platforms from `http://dev.mysql.com/downloads/cluster/'. *Note*: Binary releases and RPMs were not available for MySQL Cluster NDB 6.2 prior to MySQL Cluster NDB 6.2.15. MySQL Cluster release numbers Starting with MySQL Cluster NDB 6.1 and MySQL Cluster NDB 6.2, MySQL Cluster follows a somewhat different release pattern from the mainline MySQL 5.1 Cluster series of releases. In this `Manual' and other MySQL documentation, we identify these and later MySQL Cluster releases employing a version number that begins with `NDB'. This version number is that of the *Note `NDBCLUSTER': mysql-cluster. storage engine used in the release, and not of the MySQL server version on which the MySQL Cluster release is based. Version strings used in MySQL Cluster NDB 6.x and 7.x software The version string displayed by MySQL Cluster NDB 6.x and 7.x software uses this format: mysql-MYSQL_SERVER_VERSION-ndb-NDBCLUSTER_ENGINE_VERSION MYSQL_SERVER_VERSION represents the version of the MySQL Server on which the MySQL Cluster release is based. For all MySQL Cluster NDB 6.x and 7.x releases, this is `5.1'. NDBCLUSTER_ENGINE_VERSION is the version of the *Note `NDBCLUSTER': mysql-cluster. storage engine used by this release of the MySQL Cluster software. You can see this format used in the *Note `mysql': mysql. client, as shown here: shell> mysql Welcome to the MySQL monitor. Commands end with ; or \g. Your MySQL connection id is 2 Server version: 5.1.56-ndb-7.1.16 Source distribution Type 'help;' or '\h' for help. Type '\c' to clear the buffer. mysql> SELECT VERSION()\G *************************** 1. row *************************** VERSION(): 5.1.56-ndb-7.1.16 1 row in set (0.00 sec) This version string is also displayed in the output of the `SHOW' command in the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client: ndb_mgm> SHOW Connected to Management Server at: localhost:1186 Cluster Configuration --------------------- [ndbd(NDB)] 2 node(s) id=1 @10.0.10.6 (5.1.56-ndb-7.1.16, Nodegroup: 0, Master) id=2 @10.0.10.8 (5.1.56-ndb-7.1.16, Nodegroup: 0) [ndb_mgmd(MGM)] 1 node(s) id=3 @10.0.10.2 (5.1.56-ndb-7.1.16) [mysqld(API)] 2 node(s) id=4 @10.0.10.10 (5.1.56-ndb-7.1.16) id=5 (not connected, accepting connect from any host) The version string identifies the mainline MySQL version from which the MySQL Cluster release was branched and the version of the *Note `NDBCLUSTER': mysql-cluster. storage engine used. For example, the full version string for MySQL Cluster NDB 7.0.5 (the first GA MySQL Cluster NDB 7.0 binary release) was `mysql-5.1.32-ndb-7.0.5'. From this we can determine the following: * Since the portion of the version string preceding ``-ndb-'' is the base MySQL Server version, this means that MySQL Cluster NDB 7.0.5 derives from the MySQL 5.1.32, and contains all feature enhancements and bugfixes from MySQL 5.1 up to and including MySQL 5.1.32. * Since the portion of the version string following ``-ndb-'' represents the version number of the *Note `NDB': mysql-cluster. (or *Note `NDBCLUSTER': mysql-cluster.) storage engine, MySQL Cluster NDB 7.0.5 uses version 7.0.5 of the *Note `NDBCLUSTER': mysql-cluster. storage engine. New MySQL Cluster releases are numbered according to updates in the `NDB' storage engine, and do not necessarily correspond in a linear fashion with mainline MySQL Server releases. For example, MySQL Cluster NDB 7.0.5 (as previously noted) is based on MySQL 5.1.32, and MySQL Cluster NDB 7.0.6 is based on MySQL 5.1.34 (version string: `mysql-5.1.34-ndb-7.0.6'). Compatibility with standard MySQL 5.1 releases While many standard MySQL schemas and applications can work using MySQL Cluster, it is also true that unmodified applications and database schemas may be slightly incompatible or have suboptimal performance when run using MySQL Cluster (see *Note mysql-cluster-limitations::). Most of these issues can be overcome, but this also means that you are very unlikely to be able to switch an existing application datastore--that currently uses, for example, *Note `MyISAM': myisam-storage-engine. or *Note `InnoDB': innodb-storage-engine.--to use the *Note `NDB': mysql-cluster. storage engine without allowing for the possibility of changes in schemas, queries, and applications. Moreover, from MySQL 5.1.24 onwards, the MySQL Server and MySQL Cluster codebases diverge considerably (and *Note `NDB': mysql-cluster. storage engine support dropped from subsequent MySQL Server releases), so that the standard *Note `mysqld': mysqld. cannot function as a dropin replacement for the version of *Note `mysqld': mysqld. that is supplied with MySQL Cluster. MySQL Cluster development source trees MySQL Cluster development trees can also be accessed from `https://code.launchpad.net/~mysql/': * `MySQL Cluster NDB 6.1 (https://code.launchpad.net/~mysql/mysql-server/mysql-5.1-telco-6.1)' (_ABANDONED--no longer maintained_) * `MySQL Cluster NDB 6.2 (https://code.launchpad.net/~mysql/mysql-server/mysql-5.1-telco-6.2)' (_OBSOLETE_--in maintenance mode) * `MySQL Cluster NDB 6.3 (https://code.launchpad.net/~mysql/mysql-server/mysql-5.1-telco-6.3)' (_PAST CURRENT_--still maintained) * `MySQL Cluster NDB 7.0 (https://code.launchpad.net/~mysql/mysql-server/mysql-cluster-7.0)' (_CURRENT_) * `MySQL Cluster NDB 7.1 (https://code.launchpad.net/~mysql/mysql-server/mysql-cluster-7.1)' (_CURRENT_) The MySQL Cluster development sources maintained at `https://code.launchpad.net/~mysql/' are licensed under the GPL. For information about obtaining MySQL sources using Bazaar and building them yourself, see *Note installing-development-tree::. Currently, MySQL Cluster NDB 6.3, MySQL Cluster NDB 7.0, and MySQL Cluster NDB 7.1 releases are all Generally Available (GA), although we recommend that new deployments use MySQL Cluster NDB 7.1. MySQL Cluster NDB 6.1 is no longer in active development. For an overview of major features added in MySQL Cluster NDB 6.x and 7.x releases, see *Note mysql-cluster-development::. This chapter represents a work in progress, and its contents are subject to revision as MySQL Cluster continues to evolve. Additional information regarding MySQL Cluster can be found on the MySQL Web site at http://www.mysql.com/products/cluster/. Additional Resources More information may be found in the following places: * For answers to some commonly asked questions about MySQL Cluster, see *Note faqs-mysql-cluster::. * The MySQL Cluster mailing list: `http://lists.mysql.com/cluster'. * The MySQL Cluster Forum: `http://forums.mysql.com/list.php?25'. * Many MySQL Cluster users and developers blog about their experiences with MySQL Cluster, and make feeds of these available through PlanetMySQL (http://www.planetmysql.org/). * If you are new to MySQL Cluster, you may find our Developer Zone article `How to set up a MySQL Cluster for two servers (http://dev.mysql.com/tech-resources/articles/mysql-cluster-for-two-servers.html)' to be helpful.  File: manual.info, Node: mysql-cluster-overview, Next: mysql-cluster-installation, Prev: mysql-cluster, Up: mysql-cluster 17.1 MySQL Cluster Overview =========================== * Menu: * mysql-cluster-basics:: MySQL Cluster Core Concepts * mysql-cluster-nodes-groups:: MySQL Cluster Nodes, Node Groups, Replicas, and Partitions * mysql-cluster-overview-requirements:: MySQL Cluster Hardware, Software, and Networking Requirements * mysql-cluster-development:: MySQL Cluster Development History * mysql-cluster-compared:: MySQL Server using `InnoDB' Compared with MySQL Cluster * mysql-cluster-limitations:: Known Limitations of MySQL Cluster _MySQL Cluster_ is a technology that enables clustering of in-memory databases in a shared-nothing system. The shared-nothing architecture enables the system to work with very inexpensive hardware, and with a minimum of specific requirements for hardware or software. MySQL Cluster is designed not to have any single point of failure. In a shared-nothing system, each component is expected to have its own memory and disk, and the use of shared storage mechanisms such as network shares, network file systems, and SANs is not recommended or supported. MySQL Cluster integrates the standard MySQL server with an in-memory clustered storage engine called *Note `NDB': mysql-cluster. (which stands for `_N_etwork _D_ata_B_ase'). In our documentation, the term *Note `NDB': mysql-cluster. refers to the part of the setup that is specific to the storage engine, whereas `MySQL Cluster' refers to the combination of one or more MySQL servers with the *Note `NDB': mysql-cluster. storage engine. A MySQL Cluster consists of a set of computers, known as _hosts_, each running one or more processes. These processes, known as _nodes_, may include MySQL servers (for access to NDB data), data nodes (for storage of the data), one or more management servers, and possibly other specialized data access programs. The relationship of these components in a MySQL Cluster is shown here: MySQL Cluster Components All these programs work together to form a MySQL Cluster (see *Note mysql-cluster-programs::. When data is stored by the *Note `NDB': mysql-cluster. storage engine, the tables (and table data) are stored in the data nodes. Such tables are directly accessible from all other MySQL servers (SQL nodes) in the cluster. Thus, in a payroll application storing data in a cluster, if one application updates the salary of an employee, all other MySQL servers that query this data can see this change immediately. Although a MySQL Cluster SQL node uses the *Note `mysqld': mysqld. server damon, it differs in a number of critical respects from the *Note `mysqld': mysqld. binary supplied with the MySQL 5.1 distributions, and the two versions of *Note `mysqld': mysqld. are not interchangeable. In addition, a MySQL server that is not connected to a MySQL Cluster cannot use the *Note `NDB': mysql-cluster. storage engine and cannot access any MySQL Cluster data. The data stored in the data nodes for MySQL Cluster can be mirrored; the cluster can handle failures of individual data nodes with no other impact than that a small number of transactions are aborted due to losing the transaction state. Because transactional applications are expected to handle transaction failure, this should not be a source of problems. Individual nodes can be stopped and restarted, and can then rejoin the system (cluster). Rolling restarts (in which all nodes are restarted in turn) are used in making configuration changes and software upgrades (see *Note mysql-cluster-rolling-restart::). In MySQL Cluster NDB 7.0 and later, rolling restarts are also used as part of the process of adding new data nodes online (see *Note mysql-cluster-online-add-node::). For more information about data nodes, how they are organized in a MySQL Cluster, and how they handle and store MySQL Cluster data, see *Note mysql-cluster-nodes-groups::. Backing up and restoring MySQL Cluster databases can be done using the NDB native functionality found in the MySQL Cluster management client and the *Note `ndb_restore': mysql-cluster-programs-ndb-restore. program included in the MySQL Cluster distribution. For more information, see *Note mysql-cluster-backup::, and *Note mysql-cluster-programs-ndb-restore::. You can also use the standard MySQL functionality provided for this purpose in *Note `mysqldump': mysqldump. and the MySQL server. See *Note mysqldump::, for more information. MySQL Cluster nodes can use a number of different transport mechanisms for inter-node communications, including TCP/IP using standard 100 Mbps or faster Ethernet hardware. It is also possible to use the high-speed _Scalable Coherent Interface_ (SCI) protocol with MySQL Cluster, although this is not required to use MySQL Cluster. SCI requires special hardware and software; see *Note mysql-cluster-interconnects::, for more about SCI and using it with MySQL Cluster.  File: manual.info, Node: mysql-cluster-basics, Next: mysql-cluster-nodes-groups, Prev: mysql-cluster-overview, Up: mysql-cluster-overview 17.1.1 MySQL Cluster Core Concepts ---------------------------------- _*Note `NDBCLUSTER': mysql-cluster._ (also known as *Note `NDB': mysql-cluster.) is an in-memory storage engine offering high-availability and data-persistence features. The *Note `NDBCLUSTER': mysql-cluster. storage engine can be configured with a range of failover and load-balancing options, but it is easiest to start with the storage engine at the cluster level. MySQL Cluster's *Note `NDB': mysql-cluster. storage engine contains a complete set of data, dependent only on other data within the cluster itself. The `Cluster' portion of MySQL Cluster is configured independently of the MySQL servers. In a MySQL Cluster, each part of the cluster is considered to be a _node_. *Note*: In many contexts, the term `node' is used to indicate a computer, but when discussing MySQL Cluster it means a _process_. It is possible to run multiple nodes on a single computer; for a computer on which one or more cluster nodes are being run we use the term _cluster host_. There are three types of cluster nodes, and in a minimal MySQL Cluster configuration, there will be at least three nodes, one of each of these types: * _Management node_: The role of this type of node is to manage the other nodes within the MySQL Cluster, performing such functions as providing configuration data, starting and stopping nodes, running backup, and so forth. Because this node type manages the configuration of the other nodes, a node of this type should be started first, before any other node. An MGM node is started with the command *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. * _Data node_: This type of node stores cluster data. There are as many data nodes as there are replicas, times the number of fragments (see *Note mysql-cluster-nodes-groups::). For example, with two replicas, each having two fragments, you need four data nodes. One replica is sufficient for data storage, but provides no redundancy; therefore, it is recommended to have 2 (or more) replicas to provide redundancy, and thus high availability. A data node is started with the command *Note `ndbd': mysql-cluster-programs-ndbd. (see *Note mysql-cluster-programs-ndbd::). In MySQL Cluster NDB 7.0 and later, *Note `ndbmtd': mysql-cluster-programs-ndbmtd. can also be used for the data node process; see *Note mysql-cluster-programs-ndbmtd::, for more information. MySQL Cluster tables in MySQL 5.1 are normally stored completely in memory rather than on disk (this is why we refer to MySQL cluster as an _in-memory_ database). In MySQL 5.1, MySQL Cluster NDB 6.X, and later, some MySQL Cluster data can be stored on disk; see *Note mysql-cluster-disk-data::, for more information. * _SQL node_: This is a node that accesses the cluster data. In the case of MySQL Cluster, an SQL node is a traditional MySQL server that uses the *Note `NDBCLUSTER': mysql-cluster. storage engine. An SQL node is a *Note `mysqld': mysqld. process started with the `--ndbcluster' and `--ndb-connectstring' options, which are explained elsewhere in this chapter, possibly with additional MySQL server options as well. An SQL node is actually just a specialized type of _API node_, which designates any application which accesses MySQL Cluster data. Another example of an API node is the *Note `ndb_restore': mysql-cluster-programs-ndb-restore. utility that is used to restore a cluster backup. It is possible to write such applications using the NDB API. For basic information about the NDB API, see Getting Started with the NDB API (http://dev.mysql.com/doc/ndbapi/en/ndb-getting-started.html#ndb-getting-started). *Important*: It is not realistic to expect to employ a three-node setup in a production environment. Such a configuration provides no redundancy; to benefit from MySQL Cluster's high-availability features, you must use multiple data and SQL nodes. The use of multiple management nodes is also highly recommended. For a brief introduction to the relationships between nodes, node groups, replicas, and partitions in MySQL Cluster, see *Note mysql-cluster-nodes-groups::. Configuration of a cluster involves configuring each individual node in the cluster and setting up individual communication links between nodes. MySQL Cluster is currently designed with the intention that data nodes are homogeneous in terms of processor power, memory space, and bandwidth. In addition, to provide a single point of configuration, all configuration data for the cluster as a whole is located in one configuration file. The management server manages the cluster configuration file and the cluster log. Each node in the cluster retrieves the configuration data from the management server, and so requires a way to determine where the management server resides. When interesting events occur in the data nodes, the nodes transfer information about these events to the management server, which then writes the information to the cluster log. In addition, there can be any number of cluster client processes or applications. These include standard MySQL clients, `NDB'-specific API programs, and management clients. These are described in the next few paragraphs. Standard MySQL clients MySQL Cluster can be used with existing MySQL applications written in PHP, Perl, C, C++, Java, Python, Ruby, and so on. Such client applications send SQL statements to and receive responses from MySQL servers acting as MySQL Cluster SQL nodes in much the same way that they interact with standalone MySQL servers. MySQL clients using a MySQL Cluster as a data source can be modified to take advantage of the ability to connect with multiple MySQL servers to achieve load balancing and failover. For example, Java clients using Connector/J 5.0.6 and later can use `jdbc:mysql:loadbalance://' URLs (improved in Connector/J 5.1.7) to achieve load balancing transparently; for more information about using Connector/J with MySQL Cluster, see Using Connector/J with MySQL Cluster (http://dev.mysql.com/doc/ndbapi/en/mccj-using-connectorj.html). `NDB' client programs Client programs can be written that access MySQL Cluster data directly from the `NDBCLUSTER' storage engine, bypassing any MySQL Servers that may connected to the cluster, using the _NDB API_, a high-level C++ API. Such applications may be useful for specialized purposes where an SQL interface to the data is not needed. For more information, see The NDB API (http://dev.mysql.com/doc/ndbapi/en/ndbapi.html#ndbapi). Beginning with MySQL Cluster NDB 7.1, `NDB'-specific Java applications can also be written for MySQL Cluster, using the _MySQL Cluster Connector for Java_. This MySQL Cluster Connector includes _ClusterJ_, a high-level database API similar to object-relational mapping persistence frameworks such as Hibernate and JPA that connect directly to `NDBCLUSTER', and so does not require access to a MySQL Server. Support is also provided in MySQL Cluster NDB 7.1 and later for _ClusterJPA_, an OpenJPA implementation for MySQL Cluster that leverages the strengths of ClusterJ and JDBC; ID lookups and other fast operations are performed using ClusterJ (bypassing the MySQL Server), while more complex queries that can benefit from MySQL's query optimizer are sent through the MySQL Server, using JDBC. See Java and MySQL Cluster (http://dev.mysql.com/doc/ndbapi/en/mccj-overview-java.html), and The ClusterJ API and Data Object Model (http://dev.mysql.com/doc/ndbapi/en/mccj-overview-clusterj-object-models.html), for more information. Management clients These clients connect to the management server and provide commands for starting and stopping nodes gracefully, starting and stopping message tracing (debug versions only), showing node versions and status, starting and stopping backups, and so on. An example of this type of program is the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. management client supplied with MySQL Cluster (see *Note mysql-cluster-programs-ndb-mgm::). Such applications can be written using the _MGM API_, a C-language API that communicates directly with one or more MySQL Cluster management servers. For more information, see The MGM API (http://dev.mysql.com/doc/ndbapi/en/mgm-api.html). Oracle also makes available MySQL Cluster Manager, which provides an advanced command-line interface simplifying many complex MySQL Cluster management tasks, such restarting a MySQL Cluster with a large number of nodes. The MySQL Cluster Manager client also supports commands for getting and setting the values of most node configuration parameters as well as *Note `mysqld': mysqld. server options and variables relating to MySQL Cluster. MySQL Cluster Manager 1.1 provides support for adding data nodes online. See MySQL(tm) Cluster Manager 1.1 User Manual (http://dev.mysql.com/doc/cluster-manager/en/index.html), for more information. Event logs MySQL Cluster logs events by category (startup, shutdown, errors, checkpoints, and so on), priority, and severity. A complete listing of all reportable events may be found in *Note mysql-cluster-event-reports::. Event logs are of the two types listed here: * _Cluster log_: Keeps a record of all desired reportable events for the cluster as a whole. * _Node log_: A separate log which is also kept for each individual node. *Note*: Under normal circumstances, it is necessary and sufficient to keep and examine only the cluster log. The node logs need be consulted only for application development and debugging purposes. Checkpoint Generally speaking, when data is saved to disk, it is said that a _checkpoint_ has been reached. More specific to MySQL Cluster, a checkpoint is a point in time where all committed transactions are stored on disk. With regard to the *Note `NDB': mysql-cluster. storage engine, there are two types of checkpoints which work together to ensure that a consistent view of the cluster's data is maintained. These are shown in the following list: * _Local Checkpoint (LCP)_: This is a checkpoint that is specific to a single node; however, LCP's take place for all nodes in the cluster more or less concurrently. An LCP involves saving all of a node's data to disk, and so usually occurs every few minutes. The precise interval varies, and depends upon the amount of data stored by the node, the level of cluster activity, and other factors. * _Global Checkpoint (GCP)_: A GCP occurs every few seconds, when transactions for all nodes are synchronized and the redo-log is flushed to disk.  File: manual.info, Node: mysql-cluster-nodes-groups, Next: mysql-cluster-overview-requirements, Prev: mysql-cluster-basics, Up: mysql-cluster-overview 17.1.2 MySQL Cluster Nodes, Node Groups, Replicas, and Partitions ----------------------------------------------------------------- This section discusses the manner in which MySQL Cluster divides and duplicates data for storage. A number of concepts central to an understanding of this topic are discussed in the next few paragraphs. (Data) Node An *Note `ndbd': mysql-cluster-programs-ndbd. process, which stores a _replica_ --that is, a copy of the _partition_ (see below) assigned to the node group of which the node is a member. Each data node should be located on a separate computer. While it is also possible to host multiple *Note `ndbd': mysql-cluster-programs-ndbd. processes on a single computer, such a configuration is not supported. It is common for the terms `node' and `data node' to be used interchangeably when referring to an *Note `ndbd': mysql-cluster-programs-ndbd. process; where mentioned, management nodes (*Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. processes) and SQL nodes (*Note `mysqld': mysqld. processes) are specified as such in this discussion. Node Group A node group consists of one or more nodes, and stores partitions, or sets of _replicas_ (see next item). The number of node groups in a MySQL Cluster is not directly configurable; it is a function of the number of data nodes and of the number of replicas (`NoOfReplicas' configuration parameter), as shown here: [NUMBER_OF_NODE_GROUPS] = NUMBER_OF_DATA_NODES / `NoOfReplicas' Thus, a MySQL Cluster with 4 data nodes has 4 node groups if `NoOfReplicas' is set to 1 in the `config.ini' file, 2 node groups if `NoOfReplicas' is set to 2, and 1 node group if `NoOfReplicas' is set to 4. Replicas are discussed later in this section; for more information about `NoOfReplicas', see *Note mysql-cluster-ndbd-definition::. *Note*: All node groups in a MySQL Cluster must have the same number of data nodes. Prior to MySQL Cluster NDB 7.0, it was not possible to add new data nodes to a MySQL Cluster without shutting down the cluster completely and reloading all of its data. In MySQL Cluster NDB 7.0 (beginning with MySQL Cluster version NDB 6.4.0), you can add new node groups (and thus new data nodes) to a running MySQL Cluster--see *Note mysql-cluster-online-add-node::, for information about how this can be done. Partition This is a portion of the data stored by the cluster. There are as many cluster partitions as nodes participating in the cluster. Each node is responsible for keeping at least one copy of any partitions assigned to it (that is, at least one replica) available to the cluster. A replica belongs entirely to a single node; a node can (and usually does) store several replicas. `NDB' and user-defined partitioning MySQL Cluster normally partitions *Note `NDBCLUSTER': mysql-cluster. tables automatically. However, in MySQL 5.1 and later MySQL Cluster releases, it is possible to employ user-defined partitioning with *Note `NDBCLUSTER': mysql-cluster. tables. This is subject to the following limitations: 1. Only `KEY' and `LINEAR KEY' partitioning schemes can be used with *Note `NDBCLUSTER': mysql-cluster. tables. 2. When using *Note `ndbd': mysql-cluster-programs-ndbd, the maximum number of partitions that may be defined explicitly for any *Note `NDBCLUSTER': mysql-cluster. table is 4 per node group, times `NoOfReplicas'. (The number of node groups in a MySQL Cluster is determined as discussed previously in this section.) When using *Note `ndbmtd': mysql-cluster-programs-ndbmtd, this maximum is also affected by the number of local query handler threads, which is determined by the value of the `MaxNoOfExecutionThreads' configuration parameter. In such cases, the maxmimum number of partitions that may be defined explicitly for an *Note `NDB': mysql-cluster. table is equal to `MaxNoOfExecutionThreads * NoOfReplicas * [NUMBER OF DATA NODES]'. See *Note mysql-cluster-programs-ndbmtd::, for more information. For more information relating to MySQL Cluster and user-defined partitioning, see *Note mysql-cluster-limitations::, and *Note partitioning-limitations-storage-engines::. Replica This is a copy of a cluster partition. Each node in a node group stores a replica. Also sometimes known as a _partition replica_. The number of replicas is equal to the number of nodes per node group. The following diagram illustrates a MySQL Cluster with four data nodes, arranged in two node groups of two nodes each; nodes 1 and 2 belong to node group 0, and nodes 3 and 4 belong to node group 1. Note that only data (*Note `ndbd': mysql-cluster-programs-ndbd.) nodes are shown here; although a working cluster requires an *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. process for cluster management and at least one SQL node to access the data stored by the cluster, these have been omitted in the figure for clarity. A MySQL Cluster, with 2 node groups having 2 nodes each The data stored by the cluster is divided into four partitions, numbered 0, 1, 2, and 3. Each partition is stored--in multiple copies--on the same node group. Partitions are stored on alternate node groups as follows: * Partition 0 is stored on node group 0; a _primary replica_ (primary copy) is stored on node 1, and a _backup replica_ (backup copy of the partition) is stored on node 2. * Partition 1 is stored on the other node group (node group 1); this partition's primary replica is on node 3, and its backup replica is on node 4. * Partition 2 is stored on node group 0. However, the placing of its two replicas is reversed from that of Partition 0; for Partition 2, the primary replica is stored on node 2, and the backup on node 1. * Partition 3 is stored on node group 1, and the placement of its two replicas are reversed from those of partition 1. That is, its primary replica is located on node 4, with the backup on node 3. What this means regarding the continued operation of a MySQL Cluster is this: so long as each node group participating in the cluster has at least one node operating, the cluster has a complete copy of all data and remains viable. This is illustrated in the next diagram. Nodes required to keep a 2x2 cluster viable In this example, where the cluster consists of two node groups of two nodes each, any combination of at least one node in node group 0 and at least one node in node group 1 is sufficient to keep the cluster `alive' (indicated by arrows in the diagram). However, if _both_ nodes from _either_ node group fail, the remaining two nodes are not sufficient (shown by the arrows marked out with an *X*); in either case, the cluster has lost an entire partition and so can no longer provide access to a complete set of all cluster data.  File: manual.info, Node: mysql-cluster-overview-requirements, Next: mysql-cluster-development, Prev: mysql-cluster-nodes-groups, Up: mysql-cluster-overview 17.1.3 MySQL Cluster Hardware, Software, and Networking Requirements -------------------------------------------------------------------- One of the strengths of MySQL Cluster is that it can be run on commodity hardware and has no unusual requirements in this regard, other than for large amounts of RAM, due to the fact that all live data storage is done in memory. (It is possible to reduce this requirement using Disk Data tables--see *Note mysql-cluster-disk-data::, for more information about these.) Naturally, multiple and faster CPUs can enhance performance. Memory requirements for other MySQL Cluster processes are relatively small. The software requirements for MySQL Cluster are also modest. Host operating systems do not require any unusual modules, services, applications, or configuration to support MySQL Cluster. For supported operating systems, a standard installation should be sufficient. The MySQL software requirements are simple: all that is needed is a production release of MySQL 5.1.56-ndb-7.0.27 or 5.1.56-ndb-7.1.16 to have MySQL Cluster support. It is not strictly necessary to compile MySQL yourself merely to be able to use MySQL Cluster. We assume that you are using the binaries appropriate to your platform, available from the MySQL Cluster software downloads page at `http://dev.mysql.com/downloads/cluster/'. For communication between nodes, MySQL Cluster supports TCP/IP networking in any standard topology, and the minimum expected for each host is a standard 100 Mbps Ethernet card, plus a switch, hub, or router to provide network connectivity for the cluster as a whole. We strongly recommend that a MySQL Cluster be run on its own subnet which is not shared with machines not forming part of the cluster for the following reasons: * Security Communications between MySQL Cluster nodes are not encrypted or shielded in any way. The only means of protecting transmissions within a MySQL Cluster is to run your MySQL Cluster on a protected network. If you intend to use MySQL Cluster for Web applications, the cluster should definitely reside behind your firewall and not in your network's De-Militarized Zone (DMZ (http://compnetworking.about.com/cs/networksecurity/g/bldef_dmz.htm)) or elsewhere. See *Note mysql-cluster-security-networking-issues::, for more information. * Efficiency Setting up a MySQL Cluster on a private or protected network enables the cluster to make exclusive use of bandwidth between cluster hosts. Using a separate switch for your MySQL Cluster not only helps protect against unauthorized access to MySQL Cluster data, it also ensures that MySQL Cluster nodes are shielded from interference caused by transmissions between other computers on the network. For enhanced reliability, you can use dual switches and dual cards to remove the network as a single point of failure; many device drivers support failover for such communication links. Network communication and latency MySQL Cluster requires communication between data nodes and API nodes (including SQL nodes), as well as between data nodes and other data nodes, to execute queries and updates. Communication latency between these processes can directly affect the observed performance and latency of user queries. In addition, to maintain consistency and service despite the silent failure of nodes, MySQL Cluster uses heartbeating and timeout mechanisms which treat an extended loss of communication from a node as node failure. This can lead to reduced redundancy. Recall that, to maintain data consistency, a MySQL Cluster shuts down when the last node in a node group fails. Thus, to avoid increasing the risk of a forced shutdown, breaks in communication between nodes should be avoided wherever possible. The failure of a data or API node results in the abort of all uncommitted transactions involving the failed node. Data node recovery requires synchronization of the failed notde's data from a surviving data node, and re-establishment of disk-based redo and checkpoint logs, before the data node returns to service. This recovery can take some time, during which the Cluster operates with reduced redundancy. Heartbeating relies on timely generation of heartbeat signals by all nodes. This may not be possible if the node is overloaded, has insufficient machine CPU due to sharing with other programs, or is experiencing delays due to swapping. If heartbeat generation is sufficiently delayed, other nodes treat the node that is slow to respond as failed. This treatment of a slow node as a failed one may or may not be desireable in some circumstances, depending on the impact of the node's slowed operation on the rest of the cluster. When setting timeout values such as `HeartbeatIntervalDbDb' and `HeartbeatIntervalDbApi' for MySQL Cluster, care must be taken care to achieve quick detection, failover, and return to service, while avoiding potentially expensive false positives. Where communication latencies between data nodes are expected to be higher than would be expected in a LAN environment (on the order of 100 µs), timeout parameters must be increased to ensure that any allowed periods of latency periods are well within configured timeouts. Increasing timeouts in this way has a corresponding effect on the worst-case time to detect failure and therefore time to service recovery. LAN environments can typically be configured with stable low latency, and such that they can provide redundancy with fast failover. Individual link failures can be recovered from with minimal and controlled latency visible at the TCP level (where MySQL Cluster normally operates). WAN environments may offer a range of latencies, as well as redundancy with slower failover times. Individual link failures may require route changes to propagate before end-to-end connectivity is restored. At the TCP level this can appear as large latencies on individual channels. The worst-case observed TCP latency in these scenarios is related to the worst-case time for the IP layer to reroute around the failures. SCI support It is also possible to use the high-speed Scalable Coherent Interface (SCI) with MySQL Cluster, but this is not a requirement. See *Note mysql-cluster-interconnects::, for more about this protocol and its use with MySQL Cluster.  File: manual.info, Node: mysql-cluster-development, Next: mysql-cluster-compared, Prev: mysql-cluster-overview-requirements, Up: mysql-cluster-overview 17.1.4 MySQL Cluster Development History ---------------------------------------- * Menu: * mysql-cluster-development-5-1-ndb-7-2:: MySQL Cluster Development in MySQL Cluster NDB 7.2 * mysql-cluster-development-5-1-ndb-7-1:: MySQL Cluster Development in MySQL Cluster NDB 7.1 * mysql-cluster-development-5-1-ndb-7-0:: MySQL Cluster Development in MySQL Cluster NDB 7.0 * mysql-cluster-development-5-1-ndb-6-3:: MySQL Cluster Development in MySQL Cluster NDB 6.3 * mysql-cluster-development-5-1-ndb-6-2:: MySQL Cluster Development in MySQL Cluster NDB 6.2 * mysql-cluster-development-5-1-ndb-6-1:: MySQL Cluster Development in MySQL Cluster NDB 6.1 * mysql-cluster-development-5-1:: Development History of MySQL Cluster in MySQL 5.1 In this section, we discuss changes in the implementation of MySQL Cluster in MySQL 5.1, MySQL Cluster NDB 6.x, and MySQL Cluster NDB 7.x, as compared to earlier MySQL Cluster releases. There are a number of significant changes in the implementation of the *Note `NDBCLUSTER': mysql-cluster. storage engine in mainline MySQL 5.1 releases up to and including MySQL 5.1.23 as compared to that in MySQL 5.0; MySQL Cluster NDB 6.x and 7.x make further changes and improvements in MySQL Cluster in addition to these. The changes and features most likely to be of interest are shown in the following tables: *Note MySQL Cluster NDB 7.2: mysql-cluster-development-5-1-ndb-7-2. Distribution of MySQL users and privileges across MySQL Cluster SQL nodes Distributed pushed-down joins. Improved default values for data node configuration parameters. *Note MySQL Cluster NDB 7.1: mysql-cluster-development-5-1-ndb-7-1. Production-level support for MySQL Cluster on Microsoft Windows platforms. *Note `ndbinfo': mysql-cluster-ndbinfo. meta-information database MySQL Cluster Connector for Java, including ClusterJ and OpenJPA (ClusterJPA) support Native support for default column values *Note MySQL Cluster NDB 7.0: mysql-cluster-development-5-1-ndb-7-0. Multi-threaded data nodes (*Note `ndbmtd': mysql-cluster-programs-ndbmtd. data node daemon) Online addition of data nodes; online data redistribution MySQL on Windows (alpha; source releases only) Configuration cache Backup snapshots (`START BACKUP ... SNAPSHOTSTART', `START BACKUP ... SNAPSHOTEND' commands) IPv6 support for geo-replication Protected DDL operations Dynamic buffering for NDB transporters Increased flexibility in determining arbitration handling, using a new `Arbitration' data node configuration parameter *Note MySQL Cluster NDB 6.3: mysql-cluster-development-5-1-ndb-6-3. Conflict detection and resolution for multi-master replication Compressed backups and local checkpoints Support for *Note `OPTIMIZE TABLE': optimize-table. Parallel data node recovery Enhanced transaction coordinator selection Improved SQL statement performance metrics Transaction batching *Note `ndb_restore': mysql-cluster-programs-ndb-restore. attribute promotion Support for `epoll' (Linux only) Distribution awareness *Note `NDB': mysql-cluster. thread locks; realtime extensions for multiple CPUs *Note MySQL Cluster NDB 6.2: mysql-cluster-development-5-1-ndb-6-2. Improved backup status reporting (`BackupReportFrequency', `REPORT BackupStatus') Multiple connections per SQL node Data access with `NdbRecord' (NDB API) `REPORT MemoryUsage' command Memory allocation improvements Management client connection control Micro-GCPs Online `ADD COLUMN'; improved online index creation *Note MySQL Cluster NDB 6.1: mysql-cluster-development-5-1-ndb-6-1. Greater number of cluster nodes Disabling of arbitration Additional `DUMP' commands Faster Disk Data backups Batched slave updates *Note MySQL 5.1 (through 5.1.23): mysql-cluster-development-5-1. MySQL Cluster Replication Disk Data storage Variable-size columns User-defined partitioning Autodiscovery of table schema changes Online adding and dropping of indexes  File: manual.info, Node: mysql-cluster-development-5-1-ndb-7-2, Next: mysql-cluster-development-5-1-ndb-7-1, Prev: mysql-cluster-development, Up: mysql-cluster-development 17.1.4.1 MySQL Cluster Development in MySQL Cluster NDB 7.2 ........................................................... The following improvements to MySQL Cluster have been made in MySQL Cluster NDB 7.2. * Distribution of MySQL users and privileges Automatic distribution of MySQL users and privileges across all SQL nodes in a given MySQL Cluster is now supported. To enable this support, you must first import an SQL script `share/mysql/ndb_dist_priv.sql' that is included with the MySQL Cluster NDB 7.2 distribution. This script creates several stored procedures which you can use to enable privilege distribution and perform related tasks. When a new MySQL Server joins a MySQL Cluster where privilege distribution is in effect, it also participates in the privilege distribution automatically. Once privilege distribution is enabled, all changes to the grant tables made on any *Note `mysqld': mysqld. attached to the cluster are immediately available on any other attached MySQL Servers. This is true whether the changes are made using *Note `CREATE USER': create-user, *Note `GRANT': grant, or any of the other statements described elsewhere in this Manual (see *Note account-management-sql::.) This includes privileges relating to stored routines and views; however, automatic distribution of the views or stored routines themselves is not currently supported. For more information, see *Note mysql-cluster-privilege-distribution::. * Distributed pushed-down joins Many joins can now be pushed down to the NDB kernel for processing on MySQL Cluster data nodes. Previously, a join was handled in MySQL Cluster by means of repeated accesses of *Note `NDB': mysql-cluster. by the SQL node; however, when pushed-down joins are enabled, a pushable join is sent in its entirety to the data nodes, where it can be distributed among the data nodes and executed in parallel on multiple copies of the data, with a single, merged result being returned to *Note `mysqld': mysqld. This can reduce greatly the number of round trips between an SQL node and the data nodes required to handle such a join, leading to greatly improved performance of join processing. It is possible to determine when joins can be pushed down to the data nodes by examining the join with *Note `EXPLAIN': explain. A number of new system status variables (`Ndb_pushed_queries_defined', `Ndb_pushed_queries_dropped', `Ndb_pushed_queries_executed', and `Ndb_pushed_reads') and additions to the *Note `counters': mysql-cluster-ndbinfo-counters. table (in the *Note `ndbinfo': mysql-cluster-ndbinfo. information database) can also be helpful in determining when and how well joins are being pushed down. More information and examples are available in the description of the `ndb_join_pushdown' server system variable. See also the description of the status variables referenced in the previous paragraph, as well as *Note mysql-cluster-ndbinfo-counters::. * Improved default values for data node configuration parameters In order to provide more resiliency to environmental issues and better handling of some potential failure scenarios, and to perform more reliably with increases in memory and other resource requirements brought about by recent improvements in join handling by *Note `NDB': mysql-cluster, the default values for a number of MySQL Cluster data node configuration parameters have been changed. The parameters and changes are described in the following list: * `HeartbeatIntervalDbDb': Default increased from 1500 ms to 5000 ms. * `ArbitrationTimeout': Default increased from 3000 ms to 7500 ms. * `TimeBetweenEpochsTimeout': Now effectively disabled by default (default changed from 4000 ms to 0). * `SharedGlobalMemory': Default increased from 20 MB to 128 MB. * `MaxParallelScansPerFragment': Default increased from 32 to 256. In addition, the value computed for `MaxNoOfLocalScans' when this parameter is not set in `config.ini' has been increased by a factor of 4.  File: manual.info, Node: mysql-cluster-development-5-1-ndb-7-1, Next: mysql-cluster-development-5-1-ndb-7-0, Prev: mysql-cluster-development-5-1-ndb-7-2, Up: mysql-cluster-development 17.1.4.2 MySQL Cluster Development in MySQL Cluster NDB 7.1 ........................................................... The following improvements to MySQL Cluster have been made in MySQL Cluster NDB 7.1. * MySQL Cluster information database (`ndbinfo') The *Note `ndbinfo': mysql-cluster-ndbinfo. information database makes it possible to obtain real-time characteristics of a MySQL Cluster by issuing queries from the *Note `mysql': mysql. client or other MySQL client applications. *Note `ndbinfo': mysql-cluster-ndbinfo. provides metadata specific to MySQL Cluster similarly to how the `INFORMATION_SCHEMA' database provides metadata for the standard MySQL Server. This eliminates much of the need to read log files, issue `REPORT' or `DUMP' commands in the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client, or parse the output of *Note `ndb_config': mysql-cluster-programs-ndb-config. in order to get configuration and status information from a running MySQL Cluster. For more information, see *Note mysql-cluster-ndbinfo::. * Java connectors for MySQL Cluster The MySQL Cluster distribution now includes 2 new Java user APIs, ClusterJ and ClusterJPA. ClusterJ is an object-relational interface in a manner similar to that of Java persistence frameworks such as Hibernate. Cluster JPA is a reimplementation of OpenJPA. ClusterJ uses a backend library (NdbJTie) that provides access to the *Note `NDB': mysql-cluster. storage engine without using a MySQL Server connection or JDBC. ClusterJPA also uses NdbJTie when it improves performance, but can also process complex queries using JDBC and a MySQL Server connection, where it can take advantage of the MySQL query optimizer. ClusterJ and Cluster JPA can also be made to work with recent MySQL Cluster NDB 7.0 releases although the necessary library and JAR files are included only in MySQL Cluster NDB 7.1.1 and later. For more information about using ClusterJ and ClusterJPA, see MySQL Cluster Connector for Java (http://dev.mysql.com/doc/ndbapi/en/mccj.html). * New `CHANGE MASTER TO' option for circular replication Beginning with MySQL Cluster NDB 7.1.0, the *Note `CHANGE MASTER TO': change-master-to. statement supports an `IGNORE_SERVER_IDS' option which takes a comma-separated list of server IDs and causes events originating from the corresponding servers to be ignored. (Log rotation and log deletion events are preserved.) See *Note change-master-to::, as well as *Note show-slave-status::, for more information. * Native support for default column values Starting with MySQL Cluster NDB 7.1.4, default values for table columns are stored in the NDB kernel rather than by the MySQL server as was done previously. This means that inserts on tables having column value defaults can be smaller and faster than before, because less data must be sent from SQL nodes to `NDBCLUSTER'. Tables created using previous MySQL Cluster releases can still be used in MySQL Cluster 7.1.4 and later; however, they do not support native default values until they are upgraded. You can upgrade a table with non-native default values to support native default values using an offline *Note `ALTER TABLE': alter-table. statement. * MySQL Cluster on Windows (_Production_) Beginning with MySQL Cluster NDB 7.1.3, MySQL Cluster is available for production use on Microsoft Windows operating systems; MySQL Cluster NDB 7.1 binaries for Windows can be obtained from http://dev.mysql.com/downloads/cluster/ (http://dev.mysql.com/downloads/cluster/). Features and behavior are generally comparable to those found on previously supported platforms such as Linux and Solaris. However, you must install the binaries manually. Beginning with MySQL Cluster NDB 7.1.5, MySQL Cluster processes can be run as Windows services. If you wish to build MySQL Cluster from source on Windows, you must configure the build using the `WITH_NDBCLUSTER_STORAGE_ENGINE' option. For more information, see *Note windows-source-build::. * `--nowait-nodes' option for management servers It is now possible to configure a cluster with two management servers, but to start the cluster using only one of them by starting the management node daemon with the `--nowait-nodes' option. The other management server can then be started at a later time to join the running MySQL Cluster. * Improved lock handling for primary key lookups on `BLOB' tables A MySQL Cluster table stores all but the first 256 bytes of any *Note `BLOB': blob. or *Note `TEXT': blob. column values in a separate *Note `BLOB': blob. table; when executing queries against such tables, a shared lock is obtained. Prior to MySQL Cluster NDB 7.1.1, when the query used a primary key lookup and took place within a transaction, the lock was held for the duration of the transaction, even after no more data was being read from the *Note `NDB': mysql-cluster. table. Now in such cases, the lock is released when all *Note `BLOB': blob. data associated with the table has been read. (Bug#49190) *Note*: A shared lock is also taken for unique key lookups; it is still the case that this lock is held for the duration of the transaction. * Heartbeat thread policy and priority Beginning with MySQL Cluster NDB 7.1.2, a new configuration parameter `HeartbeatThreadPriority' makes it possible to set the policy and the priority for the heartbeat thread on management and API nodes. * Improved access to partitioning information The *Note `ndb_desc': mysql-cluster-programs-ndb-desc. utility now provides additional information about the partitioning of data stored in MySQL Cluster. Beginning with MySQL Cluster NDB 7.1.2, the `--blob-info' option causes this program to include partition information for *Note `BLOB': blob. tables in its output. Also beginning with MySQL Cluster NDB 7.1.2, the `--extra-node-info' option causes *Note `ndb_desc': mysql-cluster-programs-ndb-desc. to include information about data distribution (that is, which table fragments are stored on which data nodes). Each of these options also requires the use of the `--extra-partition-info' option. Information about partition-to-node mappings can also be obtained using the `Table::getFragmentNodes()' method, also added in MySQL Cluster NDB 7.1.2. * Replication attribute promotion and demotion Beginning with MySQL Cluster NDB 7.1.3, MySQL Cluster Replication supports attribute promotion and demotion when replicating between columns of different but similar types on the master and the slave. For example, it is possible to promote an *Note `INT': numeric-types. column on the master to a *Note `BIGINT': numeric-types. column on the slave, and to demote a *Note `TEXT': blob. column to a *Note `VARCHAR': char. column. The implementation of type demotion distinguishes between lossy and non-lossy type conversions, and their use on the slave can be controlled by setting the `slave_type_conversions' global server system variable. For more information, see *Note replication-features-attribute-promotion::. * Change in `ndbinfo' database The experimental *Note `pools': mysql-cluster-ndbinfo-pools. table was removed from *Note `ndbinfo': mysql-cluster-ndbinfo. in MySQL Cluster NDB 7.1.3. Applications which used this table can and should be rewritten to use other *Note `ndbinfo': mysql-cluster-ndbinfo. tables. * Configuration caching control Beginning with MySQL Cluster NDB 7.1.4, it is possible to disable the management server's configuration cache using the -config-cache option, which forces ndb_mgmd to read its configuration data from the config.ini configuration file every time it starts. For more information about configuration caching and this option, see *Note mysql-cluster-config-file::, as well as *Note mysql-cluster-programs-ndb-mgmd::. * Incompatible change in NDB API event reporting Beginning with MySQL Cluster NDB 7.1.4, DDL events are no longer reported on `Event' objects by default. Instead such event reporting must be enabled explicitly using the `Event::setReport()' method. For more information, see `Event::setReport()' (http://dev.mysql.com/doc/ndbapi/en/ndb-event-methods.html#ndb-event-setreport), and The `Event::EventReport' Type (http://dev.mysql.com/doc/ndbapi/en/ndb-event-types.html#ndb-event-eventreport). * Number of table attributes Beginning with MySQL Cluster NDB 7.1.4, the maximum number of attributes (columns plus indexes) per table has been increased from 128 to 512. * `InnoDB' support in commercial binaries Beginning with MySQL Cluster NDB 7.1.4b, all commercial binary releases of MySQL Cluster provide support for the `InnoDB' storage engine. * Heartbeat ordering Beginning with MySQL Cluster NDB 7.1.5, it is possible to set a specific order for transmission of heartbeats between datat nodes, using the `HeartbeatOrder' data node configuration parameter introduced in this version. This parameter can be useful in situations where multiple data nodes are running on the same host and a temporary disruption in connectivity between hosts would otherwise cause the loss of a node group (and thus failure of the cluster). * Relaxed `ndb_restore' column comparison rules When restoring data, ndb_restore compares the attributes of a column for equality with the definition of the column in the target table. However, not all of these attributes need to be the same for *Note `ndb_restore': mysql-cluster-programs-ndb-restore. to be meaningful, safe and useful. Beginning with MySQL Cluster NDB 7.1.5, *Note `ndb_restore': mysql-cluster-programs-ndb-restore. automatically ignores differences in certain column attributes which do not necessarily have to match between the version of the column in a backup and the version of that column in the MySQL Cluster to which the column data is being restored. These attributes include the following: * `COLUMN_FORMAT' setting (`FIXED', `DYNAMIC', or `DEFAULT') * `STORAGE' setting (`MEMORY' or `DISK') * The default value * The distribution key In such cases, *Note `ndb_restore': mysql-cluster-programs-ndb-restore. reports any such differences to minimize any chance of user error. * Storage of user data in `anyValue' When writing NDB events to the binary log, MySQL Cluster uses `OperationOptions::anyValue' (http://dev.mysql.com/doc/ndbapi/en/ndb-operationoptions.html#ndb-operationoptions) to store the server ID. Beginning with MySQL Cluster NDB 7.1.6, it is possible to store user data from an NDB API application in part of the `anyValue' when *Note `mysqld': mysqld. has been started with the `--server-id-bits' option set to a nondefault value. Also beginning with MySQL Cluster NDB 7.1.6, it is possible to view this data in the output of mysqlbinlog, for which its own `--server-id-bits' option is added. * `--add-drop-trigger' option for `mysqldump' Beginning with MySQL Cluster NDB 7.1.8, this option can be used to force all *Note `CREATE TRIGGER': create-trigger. statements in *Note `mysqldump': mysqldump. output to be preceded by a *Note `DROP TRIGGER IF EXISTS': drop-trigger. statement. * Forcing node shutdown and restart In MySQL Cluster NDB 7.1.8 and later, it is possible using the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. management client or the MGM API to force a data node shutdown or restart even if this would force the shutdown or restart of the entire cluster. In the management client, this is implemented through the addition of the `-f' (force) option to the `STOP' and `RESTART' commands. For more information, see *Note mysql-cluster-mgm-client-commands::. The MGM API also adds two new methods for forcing such a node shutdown or restart; see `ndb_mgm_stop4()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-stop4.html), and `ndb_mgm_restart4()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-restart4.html), for more information about these methods. * Disk Data usage statistics (`diskpagebuffer' table) MySQL Cluster 7.1.9 introduces a new table in the *Note `ndbinfo': mysql-cluster-ndbinfo. information database. The *Note `diskpagebuffer': mysql-cluster-ndbinfo-diskpagebuffer. table provides real-time data on disk page buffer usage. These statistics can be used to monitor performance of MySQL Cluster Disk Data read and write operations, and can prove useful in the tuning of Disk Data parameters such as `DiskPageBufferMemory'. * `InnoDB' Plugin support Beginning with MySQL Cluster NDB 7.1.9, the MySQL Server supplied with MySQL Cluster supports the *Note `InnoDB': innodb-storage-engine. Plugin. For more information about enabling the plugin if you are building MySQL Cluster from source, see *Note mysql-cluster-installation::. *Note*: Due to a packaging issue, the *Note `InnoDB': innodb-storage-engine. plugin was not included in RPMs for MySQL Cluster NDB 7.1.9; this issue was corrected in MySQL Cluster NDB 7.1.9a. (Bug #58283) * `TimeBetweenEpochsTimeout' and GCP stop control Beginning with MySQL Cluster NDB 7.1.10, it is possible to disable GCP stops by setting `TimeBetweenEpochsTimeout' to 0. In addition, a warning is written to the cluster log whenever the time required for a GCP save exceeds 60 seconds or the time required for a GCP commit exceeds 10 seconds. This warning includes a report of the current value of `TimeBetweenEpochsTimeout'. For more information, see *Note mysql-cluster-ndbd-definition-gcp-stop-errors::. * Skipping corrupted tables in `NDB' native backups Beginning with MySQL Cluster NDB 7.1.10, you can cause *Note `ndb_restore': mysql-cluster-programs-ndb-restore. to ignore tables that are corrupted due to missing blob parts tables by using the the `--skip-broken-objects' option. When this option is used, such tables are skipped, and the restoration of any remaining uncorrupted tables in the backup continues. * `BLOB' read and write batching Beginning with MySQL Cluster NDB 7.1.10, it possible to control batching of *Note `BLOB': blob. read and write operations. For SQL nodes, this can be done using the `--ndb-blob-read-batch-bytes' and `--ndb-blob-write-batch-bytes' options for *Note `mysqld': mysqld. In NDB API applications, you can control batching of *Note `BLOB': blob. reads and writes using the `NdbTransaction' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndbtransaction.html#ndb-ndbtransaction) methods `setMaxPendingBlobReadBytes()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndbtransaction-methods.html#ndb-ndbtransaction-setmaxpendingblobreadbytes), `getMaxPendingBlobReadBytes()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndbtransaction-methods.html#ndb-ndbtransaction-getmaxpendingblobreadbytes), `setMaxPendingBlobWriteBytes()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndbtransaction-methods.html#ndb-ndbtransaction-setmaxpendingblobwritebytes), and `getMaxPendingBlobWriteBytes()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndbtransaction-methods.html#ndb-ndbtransaction-getmaxpendingblobwritebytes). * Restoring from a NDB native backup to a differently-named database MySQL Cluster NDB 7.1.11 adds a new `--rewrite-database' option to *Note `ndb_restore': mysql-cluster-programs-ndb-restore, which makes it possible to restore to a database having a different name from that of the database in the backup. The option can be used multiple times, and it is possible to restore from more than one source database in the backup to a single target database (although no protection against table or other object name collision is provided). See *Note mysql-cluster-programs-ndb-restore::, for more information. * Selective over-commit handling Beginning with MySQL Cluster NDB 7.1.10, it is possible to exercise more direct control over uncommitted operations from transactions aborted due to timeouts flushing redo logs to disk. This is implemented using three configuration parameters added in this version of MySQL Cluster: the data node configuration parameters `RedoOverCommitCounter' and `RedoOverCommitLimit', and the API node configuration parameter `DefaultOperationRedoProblemAction'. When an attempt to flush a given redo log takes longer than `RedoOverCommitLimit' seconds, and this occurs `RedoOverCommitLimit' times or more, the transactions contained within the redo log are aborted. Any operations left uncommitted as a result are either aborted or re-tried, according to the value of `DefaultOperationRedoProblemAction'. For more information, see *Note mysql-cluster-redo-over-commit-handling:: * `INFORMATION_SCHEMA' inprovements Beginning with MySQL Cluster NDB 7.1.11, Beginning with MySQL Cluster NDB 7.0.22, `INFORMATION_SCHEMA' provides disk usage information for MySQL Cluster Disk Data tables. Previously, *Note `INFORMATION_SCHEMA.TABLES': tables-table. showed only the space usage for the in-memory data part of the table. Now, it also shows the space allocated for and used by the disk_part data of that table as well. In addition, the *Note `INFORMATION_SCHEMA.PARTITIONS': partitions-table. table (which did not show any statistics for *Note `NDB': mysql-cluster. tables) now shows correct values in this table's `TABLE_ROWS', `AVG_ROW_LENGTH', `DATA_LENGTH', `MAX_DATA_LENGTH', and `DATA_FREE' columns, for each partition. * `ndb_restore' attribute demotion Beginning with MySQL Cluster NDB 7.1.11, it is possible to enable attribute demotion when restoring a MySQL Cluster from a native backup running *Note `ndb_restore': mysql-cluster-programs-ndb-restore. with a new `--lossy-conversions' option. In general,the rules governing demotion are the same as for MySQL replication, although there are some exceptions that you may need to take into account being employing this option. See *Note replication-features-different-data-types::, for information about type conversions currently supported by attribute promotion and demotion in MySQL Cluster. * Improved multi-threaded order index building Previously, it was not possible to enable multi-threaded building of ordered indexes during initial restarts. In MySQL Cluster NDB 7.1.11, this can now be done, using the new `TwoPassInitialNodeRestartCopy' data node configuration parameter. * Configuration version information in `ndbinfo.nodes' You can see which version or versions of the MySQL Cluster configuration file are in effect on the data nodes by checking the `config_generation' column which is added to the *Note `nodes': mysql-cluster-ndbinfo-nodes. table in MySQL Cluster NDB 7.1.13. * Configuration version information in `ndbinfo.nodes' You can see which version or versions of the MySQL Cluster configuration file are in effect on the data nodes by checking the `config_generation' column which is added to the *Note `nodes': mysql-cluster-ndbinfo-nodes. table in MySQL Cluster NDB 7.1.13. * Improvements in adding data nodes online Begining with MySQL Cluster NDB 7.0.24, it is possible to add data nodes online to a running MySQL Cluster without performing a rolling restart of the cluster or starting data node processes with the `--nowait-nodes' option. This can be done by setting `Nodegroup = 65536' in the `config.ini' file for any data nodes that should be started at a later time, when first starting the cluster. The amount of time the cluster waits before doing this can be controlled using the `StartNoNodeGroupTimeout' data node configuration parameter. * Unique key updates in replication It is possible in MySQL Cluster NDB 7.1.14 and later to employ operations that update unique keys when replicating *Note `NDB': mysql-cluster. tables. Previously this could lead to duplicate key errors when trying to execute the binary log (due to the fact that row events in the binary log were ordered according to the partitioning of the base table, and could differ in order within the epoch for that in which they were executed). *Important*: Master and slave tables must both be using the *Note `NDB': mysql-cluster. storage engine for this to work. MySQL Cluster NDB 7.1 (actually, MySQL Cluster NDB 6.3 and later) is also supported by MySQL Cluster Manager, which provides an advanced command-line interface that can simplify many complex MySQL Cluster management tasks. See MySQL(tm) Cluster Manager 1.1 User Manual (http://dev.mysql.com/doc/cluster-manager/en/index.html), for more information.  File: manual.info, Node: mysql-cluster-development-5-1-ndb-7-0, Next: mysql-cluster-development-5-1-ndb-6-3, Prev: mysql-cluster-development-5-1-ndb-7-1, Up: mysql-cluster-development 17.1.4.3 MySQL Cluster Development in MySQL Cluster NDB 7.0 ........................................................... The following list provides an overview of significant feature additions and changes made in MySQL Cluster NDB 7.0. For more detailed information about all feature changes and bugfixes made in MySQL Cluster NDB 7.0, see *Note mysql-cluster-news-7-0::. *Important*: Early development versions of MySQL Cluster NDB 7.0 were known as `MySQL Cluster NDB 6.4', and the first four releases in this series were identified as MySQL Cluster NDB 6.4.0 through 6.4.3. Any information relating to these MySQL Cluster NDB 6.4.x releases appearing in this documentation apply to MySQL Cluster NDB 7.0. MySQL Cluster NDB 7.0.4 is the fifth MySQL Cluster NDB 7.0 release; it is the successor to MySQL Cluster NDB 6.4.3. * MySQL Cluster on Windows (_alpha_) MySQL Cluster NDB 7.0 is available on an experimental basis for Windows operating systems (for production use on Windows, you should use MySQL Cluster NDB 7.1.3 or later). Features and behavior comparable to those found on platforms that are already supported--such as Linux and Solaris--are planned for MySQL Cluster on Windows. In MySQL Cluster NDB 7.0, you must build from source (Windows binaries are available for MySQL Cluster NDB 7.1 releases). To enable MySQL Cluster support on Windows when building from source, you must configure the build using the `WITH_NDBCLUSTER_STORAGE_ENGINE' option. For more information, see *Note windows-source-build::. * Ability to add nodes and node groups online Beginning with MySQL Cluster NDB 6.4.0, it is possible to add new node groups (and thus new data nodes) to a running MySQL Cluster without shutting down and reloading the cluster. As part of enabling this feature, a new command `CREATE NODEGROUP' has been added to the cluster management client and the functionality of the *Note `ALTER ONLINE TABLE ... REORGANIZE PARTITION': alter-table. SQL statement has been extended. For more information, see *Note mysql-cluster-online-add-node::. * Data node multithreading support Beginning with MySQL Cluster NDB 6.4.0, a multithreaded version of the data node daemon, named *Note `ndbmtd': mysql-cluster-programs-ndbmtd, is available for use on data node hosts with multiple CPU cores. This binary is built automatically when compiling with MySQL Cluster support; no additional options other than those needed to provide MySQL Cluster support are needed when configuring the build. In most respects, *Note `ndbmtd': mysql-cluster-programs-ndbmtd. functions in the same way as *Note `ndbd': mysql-cluster-programs-ndbd, and can use the same command-line options and configuration parameters. In addition, the new `MaxNoOfExecutionThreads' configuration parameter can be used to determine the number of data node process threads for *Note `ndbmtd': mysql-cluster-programs-ndbmtd. For more information, see *Note mysql-cluster-programs-ndbmtd::. *Note*: Disk Data tables are not yet supported for use with *Note `ndbmtd': mysql-cluster-programs-ndbmtd. * Configuration cache Formerly, MySQL Cluster configuration was stateless--that is, configuration information was reloaded from the cluster's global configuration file (usually `config.ini') each time *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. was started. Beginning with MySQL Cluster NDB 6.4.0, the cluster's configuration is cached internally, and the global configuration file is no longer automatically re-read when the management server is restarted. This behavior can be controlled using the management server options `--configdir', `--initial', and `--reload'. In MySQL Cluster NDB 7.0.15 and later, the configuration cache can be disabled using the `--config-cache' option. For more information about these changes, see *Note mysql-cluster-config-file::. For more information about the new management server options, see *Note mysql-cluster-programs-ndb-mgmd::. * Detection of NDB API client connection errors In MySQL Cluster NDB 7.0 (6.4.0 and later releases), the NDB API's `Ndb_cluster_connection' class adds the `get_latest_error()' and `get_latest_error_msg()' methods for catching and diagnosing problems with NDB API client connections. * Snapshot options for backups Beginning with MySQL Cluster NDB 6.4.0, you can determine when performing a cluster backup whether the backup matches the state of the data when the backup was started or when it was completed, using the new options `SNAPSHOTSTART' and `SNAPSHOTEND' for the management client's `START BACKUP' command. See *Note mysql-cluster-backup-using-management-client::, for more information. * Dynamic NDB transporter send buffer memory allocation Previously, the NDB kernel used a fixed-size send buffer for every data node in the cluster, which was allocated when the node started. Because the size of this buffer could not be changed after the cluster was started, it was necessary to make it large enough in advance to accommodate the maximum possible load on any transporter socket. However, this was an inefficient use of memory, since much of it often went unused. Beginning with MySQL Cluster NDB 6.4.0, send buffer memory is allocated dynamically from a memory pool shared between all transporters, which means that the size of the send buffer can be adjusted as necessary. This change is reflected by the addition of the configuration parameters `TotalSendBufferMemory', `ReservedSendBufferMemory', and `OverLoadLimit', as well as a change in how the existing `SendBufferMemory' configuration parameter is used. For more information, see *Note mysql-cluster-config-send-buffers::. * Robust DDL operations Beginning with MySQL Cluster NDB 6.4.0, DDL operations (such as *Note `CREATE TABLE': create-table. or *Note `ALTER TABLE': alter-table.) are protected from data node failures; in the event of a data node failure, such operations are now rolled back gracefully. Previously, if a data node failed while trying to perform a DDL operation, the MySQL Cluster data dictionary became locked and no further DDL statements could be executed without restarting the cluster. * IPv6 support in MySQL Cluster Replication Beginning with MySQL Cluster NDB 6.4.1, IPv6 networking is supported between MySQL Cluster SQL nodes, which makes it possible to replicate between instances of MySQL Cluster using IPv6 addresses. However, IPv6 is supported only for direct connections between MySQL servers; all connections _within_ an individual MySQL Cluster must use IPv4. For more information, see *Note mysql-cluster-replication-issues::. * Restoring specific databases, tables, or columns from a MySQL Cluster backup It is now possible to exercise more fine-grained control when restoring a MySQL Cluster from backup using *Note `ndb_restore': mysql-cluster-programs-ndb-restore. Beginning with MySQL Cluster NDB 6.4.3, you can choose to restore only specified tables or databases, or exclude specific tables or databases from being restored, using the new *Note `ndb_restore': mysql-cluster-programs-ndb-restore. options `--include-tables', `--include-databases', `--exclude-tables', and `--exclude-databases'. Beginning with MySQL Cluster NDB 7.0.7, it is also possible to restore to a table having fewer columns than the original using the `--exclude-missing-columns' option. For more information about all of these options, see *Note mysql-cluster-programs-ndb-restore::. * Improved Disk Data file system configuration As of MySQL Cluster NDB 6.4.3, you can specify default locations for MySQL Cluster Disk Data data files and undo log files using the data node configuration parameters `FileSystemPathDD', `FileSystemPathDataFiles', and `FileSystemPathUndoFiles'. This eliminates the need to use symbolic links to place Disk Data files separately from other files in data node file systems to improve Disk Data performance. For more information, see *Note mysql-cluster-ndbd-disk-data-filesystem-parameters::. * Automatic creation of Disk Data log file groups and tablespaces Beginning with MySQL Cluster NDB 6.4.3, using the data node configuration parameters `InitialLogFileGroup' and `InitialTablespace', you can cause the creation of a MySQL Cluster Disk Data log file group, tablespace, or both, when the cluster is first started. When using these parameters, no SQL statements are required to create these Disk Data objects. For more information, see `Disk Data object creation parameters'. * Improved internal message passing and record handling MySQL Cluster NDB 7.0 contains 2 changes that optimize the use of network connections by addressing the size and number of messages passed between data nodes, and between data nodes and API nodes, which can increase MySQL Cluster and application performance: * Packed reads Formerly, each read request signal contained a list of columns to be retrieved, each of these column identifiers using 4 bytes within the message. This meant that the message size increased as the number of columns being fetched increased. In addition, in the response from the data node, each column result was packed to a 4-byte boundary, which resulted in wasted space. In MySQL Cluster NDB 7.0, messaging for read operations is optimized in both directions, using a bitmap in the read request to specify the columns to be fetched. Where many fields are requested, this can result in a significant message size reduction as compared with the old method. In addition, the 4-byte packing in responses is no longer used, which means that smaller fields consume less space. * Long signal transactions This enhancement reduces the number of messages and signals that are sent to data nodes for complex requests. Prior to MySQL Cluster NDB 7.0, there was a 100 byte limit on the size of the request signal, which meant that complex requests had to be split up between multiple messages prior to transmission, then reassembled on the receiving end. In addition to actual payload data, each message required its own operating system and protocol overhead such as header information. This often wasted network bandwidth and data node CPU. The maximum size of the message is now 32 KB, which is sufficient to accommodate most queries. Both of these optimizations are internal to the NDB API, and so is transparent to applications; this is true whether an application uses the NDB API directly or does so indirectly through an SQL node. * Configuration parameter data dumps Starting with MySQL Cluster NDB 7.0.6, the *Note `ndb_config': mysql-cluster-programs-ndb-config. utility supports a `--configinfo' option that causes it to dump a list of all configuration parameters supported by the cluster, along with brief descriptions, information about the parameters' default and permitted values, and the sections of the `config.ini' file in which the parameters apply. An additional `--xml' switch causes *Note `ndb_config': mysql-cluster-programs-ndb-config. to use XML rather than plaintext output. Using *Note `ndb_config `--configinfo'': mysql-cluster-programs-ndb-config. or *Note `ndb_config `--configinfo --xml'': mysql-cluster-programs-ndb-config. requires no access to a running MySQL Cluster, any other programs, or any files. For more information and examples, see *Note mysql-cluster-programs-ndb-config::. * Per-table reporting of free space on disk The *Note `INFORMATION_SCHEMA.FILES': files-table. table shows information about used and free space in MySQL Cluster Disk Data data files, but this information is not applicable to individual tables. In MySQL Cluster NDB 7.0.8 and later, the *Note `ndb_desc': mysql-cluster-programs-ndb-desc. utility provides two additional columns in its output that show the amount of space allocated on disk for a given *Note `NDB': mysql-cluster. table as well the amount of space that remains available for additional storage of disk-based column data for that table. For more information, see *Note mysql-cluster-programs-ndb-desc::. * Improved restart times Optimizations in redo log handling and other file system operations introduced in MySQL Cluster NDB 7.0.9 have the potential to reduce considerably the time required for restarts. While actual performance benefits observed in production setups will naturally vary depending on database size, hardware, and other conditions, our own preliminary testing has shown that these improvements can yield startup times that are faster than those typical of previous MySQL Cluster NDB 7.0 releases by a factor of 50 or more. * Native support for default column values Starting with MySQL Cluster NDB 7.0.15, default values for table columns are stored in the NDB kernel rather than by the MySQL server as was done previously. This means that inserts on tables having column value defaults can be smaller and faster than before, because less data must be sent from SQL nodes to `NDBCLUSTER'. Tables created using previous MySQL Cluster releases can still be used in MySQL Cluster 7.0.15 and later; however, they do not support native default values until they are upgraded. You can upgrade a table with non-native default values to support native default values using an offline *Note `ALTER TABLE': alter-table. statement. * `--nowait-nodes' option for management servers Starting with MySQL Cluster NDB 7.0.10, it is possible to configure a cluster with two management servers, but to start the cluster using only one of them by starting the management node daemon with the `--nowait-nodes' option. The other management server can then be started at a later time to join the running MySQL Cluster. * Increased flexibility in online upgrade procedure Previously, when performing an upgrade of a running MySQL cluster, the order in which the types of cluster nodes had to be upgraded was very strict. However, beginning with MySQL Cluster NDB 7.0.10, MySQL Cluster supports online upgrading of API nodes (including MySQL servers running as SQL nodes) online upgrading management nodes, data nodes, or both. *Important*: Before attempting to use this new upgrade functionality, see *Note mysql-cluster-rolling-restart::, for additional information, especially if you are planning an online upgrade to MySQL Cluster NDB 7.0 from MySQL Cluster NDB 6.3. * New `CHANGE MASTER TO' option for circular replication Beginning with MySQL Cluster NDB 7.0.11, the *Note `CHANGE MASTER TO': change-master-to. statement supports an `IGNORE_SERVER_IDS' option which takes a comma-separated list of server IDs and causes events originating from the corresponding servers to be ignored. (Log rotation and log deletion events are preserved.) See *Note change-master-to::, as well as *Note show-slave-status::, for more information. * New replication conflict resolution strategy Beginning with MySQL Cluster NDB 7.0.11, the function `NDB$MAX_DELETE_WIN()' is available to implement `greatest timestamp, delete wins' conflict resolution. See *Note mysql-cluster-replication-ndb-max-delete-win::, for more information. * Improved lock handling for primary key lookups on `BLOB' tables A MySQL Cluster table stores all but the first 256 bytes of any *Note `BLOB': blob. or *Note `TEXT': blob. column values in a separate *Note `BLOB': blob. table; when executing queries against such tables, a shared lock is obtained. Prior to MySQL Cluster NDB 7.0.12, when the query used a primary key lookup and took place within a transaction, the lock was held for the duration of the transaction, even after no more data was being read from the *Note `NDB': mysql-cluster. table. Now in such cases, the lock is released when all *Note `BLOB': blob. data associated with the table has been read. (Bug#49190) *Note*: A shared lock is also taken for unique key lookups; it is still the case that this lock is held for the duration of the transaction. * Heartbeat thread policy and priority Beginning with MySQL Cluster NDB 7.0.13, a new configuration parameter `HeartbeatThreadPriority' makes it possible to set the policy and the priority for the heartbeat thread on management and API nodes. * Improved access to partitioning information The *Note `ndb_desc': mysql-cluster-programs-ndb-desc. utility now provides additional information about the partitioning of data stored in MySQL Cluster. Beginning with MySQL Cluster NDB 7.0.13, the `--blob-info' option causes this program to include partition information for *Note `BLOB': blob. tables in its output. Beginning with MySQL Cluster NDB 7.0.14, the `--extra-node-info' option causes *Note `ndb_desc': mysql-cluster-programs-ndb-desc. to include information about data distribution (that is, which table fragments are stored on which data nodes). Each of these options also requires the use of the `--extra-partition-info' option. Information about partition-to-node mappings can also be obtained using the `Table::getFragmentNodes()' method, also added in MySQL Cluster NDB 7.0.14. * Replication attribute promotion and demotion Beginning with MySQL Cluster NDB 7.0.14, MySQL Cluster Replication supports attribute promotion and demotion when replicating between columns of different but similar types on the master and the slave. For example, it is possible to promote an *Note `INT': numeric-types. column on the master to a *Note `BIGINT': numeric-types. column on the slave, and to demote a *Note `TEXT': blob. column to a *Note `VARCHAR': char. column. The implementation of type demotion distinguishes between lossy and non-lossy type conversions, and their use on the slave can be controlled by setting the `slave_type_conversions' global server system variable. For more information, see *Note replication-features-attribute-promotion::. * Incompatible change in NDB API event reporting Beginning with MySQL Cluster NDB 7.0.15, DDL events are no longer reported on `Event' objects by default. Instead such event reporting must be enabled explicitly using the `Event::setReport()' method. For more information, see `Event::setReport()' (http://dev.mysql.com/doc/ndbapi/en/ndb-event-methods.html#ndb-event-setreport), and The `Event::EventReport' Type (http://dev.mysql.com/doc/ndbapi/en/ndb-event-types.html#ndb-event-eventreport). * Number of table attributes Beginning with MySQL Cluster NDB 7.0.15, the maximum number of attributes (columns plus indexes) per table has been increased from 128 to 512. * Heartbeat ordering Beginning with MySQL Cluster NDB 7.0.16, it is possible to set a specific order for transmission of heartbeats between data nodes, using the `HeartbeatOrder' data node configuration parameter introduced in this version. This parameter can be useful in situations where multiple data nodes are running on the same host and a temporary disruption in connectivity between hosts would otherwise cause the loss of a node group (and thus failure of the cluster). * Relaxed `ndb_restore' column comparison rules When restoring data, ndb_restore compares the attributes of a column for equality with the definition of the column in the target table. However, not all of these attributes need to be the same for *Note `ndb_restore': mysql-cluster-programs-ndb-restore. to be meaningful, safe and useful. Beginning with MySQL Cluster NDB 7.0.16, *Note `ndb_restore': mysql-cluster-programs-ndb-restore. automatically ignores differences in certain column attributes which do not necessarily have to match between the version of the column in a backup and the version of that column in the MySQL Cluster to which the column data is being restored. These attributes include the following: * `COLUMN_FORMAT' setting (`FIXED', `DYNAMIC', or `DEFAULT') * `STORAGE' setting (`MEMORY' or `DISK') * The default value * The distribution key In such cases, *Note `ndb_restore': mysql-cluster-programs-ndb-restore. reports any such differences to minimize any chance of user error. * Storage of user data in `anyValue' When writing NDB events to the binary log, MySQL Cluster uses `OperationOptions::anyValue' (http://dev.mysql.com/doc/ndbapi/en/ndb-operationoptions.html#ndb-operationoptions) to store the server ID. Beginning with MySQL Cluster NDB 7.0.17, it is possible to store user data from an NDB API application in part of the `anyValue' when *Note `mysqld': mysqld. has been started with the `--server-id-bits' option set to a nondefault value. Also beginning with MySQL Cluster NDB 7.0.17, it is possible to view this data in the output of mysqlbinlog, for which its own `--server-id-bits' option is added. * `--add-drop-trigger' option for `mysqldump' Beginning with MySQL Cluster NDB 7.0.19, this option can be used to force all *Note `CREATE TRIGGER': create-trigger. statements in *Note `mysqldump': mysqldump. output to be preceded by a *Note `DROP TRIGGER IF EXISTS': drop-trigger. statement. * Forcing node shutdown and restart In MySQL Cluster NDB 7.0.19 and later, it is possible using the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. management client or the MGM API to force a data node shutdown or restart even if this would force the shutdown or restart of the entire cluster. In the management client, this is implemented through the addition of the `-f' (force) option to the `STOP' and `RESTART' commands. For more information, see *Note mysql-cluster-mgm-client-commands::. The MGM API also adds two new methods for forcing such a node shutdown or restart; see `ndb_mgm_stop4()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-stop4.html), and `ndb_mgm_restart4()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-restart4.html), for more information about these methods. * `TimeBetweenEpochsTimeout' and GCP stop control Beginning with MySQL Cluster NDB 7.0.21, it is possible to disable GCP stops by setting `TimeBetweenEpochsTimeout' to 0. In addition, a warning is written to the cluster log whenever the time required for a GCP save exceeds 60 seconds or the time required for a GCP commit exceeds 10 seconds. This warning includes a report of the current value of `TimeBetweenEpochsTimeout'. For more information, see *Note mysql-cluster-ndbd-definition-gcp-stop-errors::. * Skipping corrupted tables in `NDB' native backups Beginning with MySQL Cluster NDB 7.0.21, you can cause *Note `ndb_restore': mysql-cluster-programs-ndb-restore. to ignore tables that are corrupted due to missing blob parts tables by using the the `--skip-broken-objects' option. When this option is used, such tables are skipped, and the restoration of any remaining uncorrupted tables in the backup continues. * `BLOB' read and write batching Beginning with MySQL Cluster NDB 7.0.21, it possible to control batching of *Note `BLOB': blob. read and write operations. For SQL nodes, this can be done using the `--ndb-blob-read-batch-bytes' and `--ndb-blob-write-batch-bytes' options for *Note `mysqld': mysqld. In NDB API applications, you can control batching of *Note `BLOB': blob. reads and writes using the `NdbTransaction' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndbtransaction.html#ndb-ndbtransaction) methods `setMaxPendingBlobReadBytes()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndbtransaction-methods.html#ndb-ndbtransaction-setmaxpendingblobreadbytes), `getMaxPendingBlobReadBytes()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndbtransaction-methods.html#ndb-ndbtransaction-getmaxpendingblobreadbytes), `setMaxPendingBlobWriteBytes()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndbtransaction-methods.html#ndb-ndbtransaction-setmaxpendingblobwritebytes), and `getMaxPendingBlobWriteBytes()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndbtransaction-methods.html#ndb-ndbtransaction-getmaxpendingblobwritebytes). * Restoring from a NDB native backup to a differently-named database MySQL Cluster NDB 7.0.22 adds a new `--rewrite-database' option to *Note `ndb_restore': mysql-cluster-programs-ndb-restore, which makes it possible to restore to a database having a different name from that of the database in the backup. The option can be used multiple times, and it is possible to restore from more than one source database in the backup to a single target database (although no protection against table or other object name collision is provided). See *Note mysql-cluster-programs-ndb-restore::, for more information. * `INFORMATION_SCHEMA' inprovements Beginning with MySQL Cluster NDB 7.0.22, `INFORMATION_SCHEMA' provides disk usage information for MySQL Cluster Disk Data tables. Previously, *Note `INFORMATION_SCHEMA.TABLES': tables-table. showed only the space usage for the in-memory data part of the table. Now, it also shows the space allocated for and used by the disk_part data of that table as well. In addition, the *Note `INFORMATION_SCHEMA.PARTITIONS': partitions-table. table (which did not show any statistics for *Note `NDB': mysql-cluster. tables) now shows correct values in this table's `TABLE_ROWS', `AVG_ROW_LENGTH', `DATA_LENGTH', `MAX_DATA_LENGTH', and `DATA_FREE' columns, for each partition. * Configuration version information in `ndbinfo.nodes' You can see which version or versions of the MySQL Cluster configuration file are in effect on the data nodes by checking the `config_generation' column which is added to the *Note `nodes': mysql-cluster-ndbinfo-nodes. table in MySQL Cluster NDB 7.0.24. * Improvements in adding data nodes online Begining with MySQL Cluster NDB 7.0.24, it is possible to add data nodes online to a running MySQL Cluster without performing a rolling restart of the cluster or starting data node processes with the `--nowait-nodes' option. This can be done by setting `Nodegroup = 65536' in the `config.ini' file for any data nodes that should be started at a later time, when first starting the cluster. The amount of time the cluster waits before doing this can be controlled using the `StartNoNodeGroupTimeout' data node configuration parameter. * Unique key updates in replication It is possible in MySQL Cluster NDB 7.0.25 and later to employ operations that update unique keys when replicating *Note `NDB': mysql-cluster. tables. Previously this could lead to duplicate key errors when trying to execute the binary log (due to the fact that row events in the binary log were ordered according to the partitioning of the base table, and could differ in order within the epoch for that in which they were executed). *Important*: Master and slave tables must both be using the *Note `NDB': mysql-cluster. storage engine for this to work. MySQL Cluster NDB 6.3, MySQL Cluster NDB 7.0, and later are also supported by MySQL Cluster Manager, which provides an advanced command-line interface that can simplify many complex MySQL Cluster management tasks. See MySQL(tm) Cluster Manager 1.1 User Manual (http://dev.mysql.com/doc/cluster-manager/en/index.html), for more information.  File: manual.info, Node: mysql-cluster-development-5-1-ndb-6-3, Next: mysql-cluster-development-5-1-ndb-6-2, Prev: mysql-cluster-development-5-1-ndb-7-0, Up: mysql-cluster-development 17.1.4.4 MySQL Cluster Development in MySQL Cluster NDB 6.3 ........................................................... The following list provides an overview of significant feature additions and changes first made in MySQL Cluster NDB 6.3. For more detailed information about all feature changes and bugfixes made in MySQL Cluster NDB 6.3, see *Note mysql-cluster-news-6-3::. * Conflict detection and resolution It is now possible to detect and resolve conflicts that arise in multi-master replication scenarios, such as circular replication, when different masters may try to update the same row on the slave with different data. Both `greatest timestamp wins' and `same timestamp wins' scenarios are supported. For more information, see *Note mysql-cluster-replication-conflict-resolution::. * Recovery of `one master, many slaves' replication setups Recovery of multi-way replication setups (`one master, many slaves') is now supported using the `--ndb-log-orig' server option and changes in the `mysql.ndb_binlog_index' table. See *Note mysql-cluster-replication-schema::, for more information. * Enhanced selection options for transaction coordinator New values and behaviors are introduced for `--ndb_optimized_node_selection', enabling greater flexibility when an SQL node chooses a transaction coordinator. For more information, see the description of `ndb_optimized_node_selection' in *Note mysql-cluster-system-variables::. * Replication heartbeats Replication heartbeats facilitate the task of monitoring and detecting failures in master-slave connections in real time. This feature is implemented using a new `MASTER_HEARTBEAT_PERIOD = VALUE' clause for the *Note `CHANGE MASTER TO': change-master-to. statement and the addition of two status variables `Slave_heartbeat_period' and `Slave_received_heartbeats'. For more information, see *Note change-master-to::. * `NDB' thread locks It is possible to lock *Note `NDB': mysql-cluster. execution threads and maintenance threads (such as file system and other operating system threads) to specific CPUs on multiprocessor data node hosts, and to leverage real-time scheduling. * Improved performance of updates using primary keys or unique keys The number of unnecessary reads when performing a primary key or unique key update has been greatly reduced. Since it is seldom necessary to read a record prior to an update, this can yield a considerable improvement in performance. In addition, primary key columns are no longer written to when not needed during update operations. * Batching improvements Support of batched *Note `DELETE': delete. and *Note `UPDATE': update. operations has been significantly improved. Batching of `UPDATE WHERE...' and multiple *Note `DELETE': delete. operations is also now implemented. * Improved SQL statement performance metrics The `Ndb_execute_count' system status variable measures the number of round trips made by SQL statements to the *Note `NDB': mysql-cluster. kernel, providing an improved metric for determining efficiency with which statements are excuted. For more information, see `MySQL Cluster Status Variables: `Ndb_execute_count''. * Compressed LCPs and backups Compressed local checkpoints and backups can save 50% or more of the disk space used by uncompressed LCPs and backups. These can be enabled using the two new data node configuration parameters `CompressedLCP' and `CompressedBackup', respectively. * `OPTIMIZE TABLE' support with `NDBCLUSTER' tables *Note `OPTIMIZE TABLE': optimize-table. is supported for dynamic columns of in-memory *Note `NDB': mysql-cluster. tables. In such cases, it is no longer necessary to drop (and possibly to re-create) a table, or to perform a rolling restart, in order to recover memory from deleted rows for general re-use by Cluster. The performance of `OPTIMIZE' on Cluster tables can be tuned by adjusting the value of the `ndb_optimization_delay' system variable, which controls the number of milliseconds to wait between processing batches of rows by *Note `OPTIMIZE TABLE': optimize-table. In addition, *Note `OPTIMIZE TABLE': optimize-table. on an *Note `NDBCLUSTER': mysql-cluster. table can be interrupted by, for example, killing the SQL thread performing the `OPTIMIZE' operation. * Batching of transactions It is possible to cause statements occurring within the same transaction to be run as a batch by setting the session variable `transaction_allow_batching' to `1' or `ON'. To use this feature, `autocommit' must be set to `0' or `OFF'. Batch sizes can be controlled using the `--ndb-batch-size' option for *Note `mysqld': mysqld. For additional information, see *Note mysql-cluster-program-options-mysqld::, and *Note mysql-cluster-system-variables::. * Attribute promotion with `ndb_restore' It is possible using *Note `ndb_restore': mysql-cluster-programs-ndb-restore. to restore data reliably from a column of a given type to a column that uses a `larger' type. This is sometimes referred to as _attribute promotion_. For example, MySQL Cluster backup data that originated in a *Note `SMALLINT': numeric-types. column can be restored to a *Note `MEDIUMINT': numeric-types, *Note `INT': numeric-types, or *Note `BIGINT': numeric-types. column. See *Note mysql-cluster-programs-ndb-restore::, for more information. * Parallel data node recovery Recovery of multiple data nodes can now be done in parallel, rather than sequentially. In other words, several data nodes can be restored concurrently, which can often result in much faster recovery times than when they are restored one at a time. * Increased local checkpoint efficiency Only 2 local checkpoints are stored, rather than 3, lowering disk space requirements and the size and number of redo log files. * `NDBCLUSTER' table persistence control Persistence of *Note `NDB': mysql-cluster. tables can be controlled using the session variables `ndb_table_temporary' and `ndb_table_no_logging'. `ndb_table_no_logging' causes *Note `NDB': mysql-cluster. tables not to be checkpointed to disk; `ndb_table_temporary' does the same, and in addition, no schema files are created. See *Note mysql-cluster-option-tables::. * Epoll support (_Linux only_) _Epoll_ is an improved method for handling file descriptors, which is more efficient than scanning to determine whether a file descriptor has data to be read. (The term _epoll_ is specific to Linux and equivalent functionality is known by other names on other platforms such as Solaris and FreeBSD.) Currently, MySQL Cluster supports this functionality on Linux only. * Distribution awareness (SQL nodes) In MySQL Cluster NDB 6.3, SQL nodes can take advantage of distribution awareness. Here we provide a brief example showing how to design a table to make a given class of queries distrubtion-aware. Suppose an *Note `NDBCLUSTER': mysql-cluster. table `t1' has the following schema: CREATE TABLE t1 ( userid INT NOT NULL, serviceid INT NOT NULL AUTO_INCREMENT PRIMARY KEY, data VARCHAR(255) ) ENGINE=NDBCLUSTER; Suppose further that most of the queries to be used in our application test values of the `userid' column of this table. The form of such a query looks something like this: SELECT COLUMNS FROM t1 WHERE userid RELATION VALUE; In this query, RELATION represents some relational operator, such as `=', `<', `>', and so on. Queries using `IN' and a list of values can also be used: SELECT COLUMNS FROM t1 WHERE userid IN VALUE_LIST; To make use of distribution awareness, we need to make the `userid' column part of the table's primary key, then explicitly partition the table with this column being used as the partitioning key. (Recall that for a partitioned table having one or more unique keys, all columns of the table's partitioning key must also be part of all of the unique keys--for more information and examples, see *Note partitioning-limitations-partitioning-keys-unique-keys::.) In other words, the table schema should be equivalent to the following *Note `CREATE TABLE': create-table. statement: CREATE TABLE t1 ( userid INT NOT NULL, serviceid INT NOT NULL AUTO_INCREMENT, data VARCHAR(255), PRIMARY KEY p (userid,serviceid) ) ENGINE=NDBCLUSTER PARTITION BY KEY(userid); When the table is partitioned in this way, all rows having the same `userid' value are found on the same node group, and the MySQL Server can immediately select the optimal node to use as the transaction coordinator. * Realtime extensions for multiple CPUs When running MySQL Cluster data nodes on hosts with multiple processors, the realtime extensions make it possible to give priority to the data node process and control on which CPU cores it should operate. This can be done using the data node configuration parameters `RealtimeScheduler', `SchedulerExecutionTimer', and `SchedulerSpinTimer'. Doing so properly can significantly lower response times and make them much more predictable response. For more information about using these parameters, see Defining Data Nodes: Realtime Performance Parameters * Fully automatic database discovery It is no longer a requirement for database autodiscovery that an SQL node already be connected to the cluster at the time that a database is created on another SQL node, or for a *Note `CREATE DATABASE': create-database. or *Note `CREATE SCHEMA': create-database. statement to be issued on the new SQL node after it joins the cluster. * Detection of NDB API client connection errors Beginning with MySQL Cluster NDB 6.3.20, the NDB API's `Ndb_cluster_connection' class adds the `get_latest_error()' and `get_latest_error_msg()' methods for catching and diagnosing problems with NDB API client connections. * Restoring specific databases, tables, or columns from a MySQL Cluster backup It is now possible to exercise more fine-grained control when restoring a MySQL Cluster from backup using *Note `ndb_restore': mysql-cluster-programs-ndb-restore. Beginning with MySQL Cluster NDB 6.3.22, you can choose to restore only specified tables or databases, or exclude specific tables or databases from being restored, using the new *Note `ndb_restore': mysql-cluster-programs-ndb-restore. options `--include-tables', `--include-databases', `--exclude-tables', and `--exclude-databases'. Beginning with MySQL Cluster NDB 6.3.26, it is also possible to restore to a table having fewer columns than the original using the `--exclude-missing-columns' option. For more information about all of these options, see *Note mysql-cluster-programs-ndb-restore::. * Improved Disk Data file system configuration As of MySQL Cluster NDB 6.3.22, you can specify default locations for MySQL Cluster Disk Data data files and undo log files using the data node configuration parameters `FileSystemPathDD', `FileSystemPathDataFiles', and `FileSystemPathUndoFiles'. This eliminates the need to use symbolic links to place Disk Data files separately from other files in data node file systems to improve Disk Data performance. For more information, see *Note mysql-cluster-ndbd-disk-data-filesystem-parameters::. * Automatic creation of Disk Data log file groups and tablespaces Beginning with MySQL Cluster NDB 6.3.22, using the data node configuration parameters `InitialLogFileGroup' and `InitialTablespace', you can cause the creation of a MySQL Cluster Disk Data log file group, tablespace, or both, when the cluster is first started. When using these parameters, no SQL statements are required to create these Disk Data objects. For more information, see `Disk Data object creation parameters'. * Configuration parameter data dumps Starting with MySQL Cluster NDB 6.3.25, the *Note `ndb_config': mysql-cluster-programs-ndb-config. utility supports a `--configinfo' option that causes it to dump a list of all configuration parameters supported by the cluster, along with brief descriptions, information about the parameters' default and permitted values, and the sections of the `config.ini' file in which the parameters apply. An additional `--xml' switch causes *Note `ndb_config': mysql-cluster-programs-ndb-config. to use XML rather than plaintext output. Using *Note `ndb_config `--configinfo'': mysql-cluster-programs-ndb-config. or *Note `ndb_config `--configinfo --xml'': mysql-cluster-programs-ndb-config. requires no access to a running MySQL Cluster, any other programs, or any files. For more information and examples, see *Note mysql-cluster-programs-ndb-config::. * Per-table reporting of free space on disk The *Note `INFORMATION_SCHEMA.FILES': files-table. table shows information about used and free space in MySQL Cluster Disk Data data files, but this information is not applicable to individual tables. In MySQL Cluster NDB 6.3.27 and later, the *Note `ndb_desc': mysql-cluster-programs-ndb-desc. utility provides two additional columns in its output that show the amount of space allocated on disk for a given *Note `NDB': mysql-cluster. table as well the amount of space that remains available for additional storage of disk-based column data for that table. For more information, see *Note mysql-cluster-programs-ndb-desc::. * Improved restart times Optimizations in redo log handling and other file system operations introduced in MySQL Cluster NDB 6.3.28 have the potential to reduce considerably the time required for restarts. While actual performance benefits observed in production setups will naturally vary depending on database size, hardware, and other conditions, our own preliminary testing has shown that these improvements can yield startup times that are faster than those typical of previous MySQL Cluster NDB 6.3 releases by a factor of 50 or more. * Increased flexibility in online upgrade procedure Previously, when performing an upgrade of a running MySQL cluster, the order in which the types of cluster nodes had to be upgraded was very strict. However, beginning with MySQL Cluster NDB 6.3.29, MySQL Cluster supports online upgrading of API nodes (including MySQL servers running as SQL nodes) before upgrading management nodes, data nodes, or both. *Important*: Before attempting to use this new upgrade functionality, see *Note mysql-cluster-rolling-restart::, for additional information, especially if you are planning an online upgrade from MySQL Cluster NDB 6.3 to MySQL Cluster NDB 7.0. * New replication conflict resolution strategy Beginning with MySQL Cluster NDB 6.3.31, the function `NDB$MAX_DELETE_WIN()' is available to implement `greatest timestamp, delete wins' conflict resolution. See *Note mysql-cluster-replication-ndb-max-delete-win::, for more information. * New `CHANGE MASTER TO' option for circular replication Beginning with MySQL Cluster NDB 6.3.31, the *Note `CHANGE MASTER TO': change-master-to. statement supports an `IGNORE_SERVER_IDS' option which takes a comma-separated list of server IDs and causes events originating from the corresponding servers to be ignored. (Log rotation and log deletion events are preserved.) See *Note change-master-to::, as well as *Note show-slave-status::, for more information. * Heartbeat thread policy and priority Beginning with MySQL Cluster NDB 6.3.32, a new configuration parameter `HeartbeatThreadPriority' makes it possible to set the policy and the priority for the heartbeat thread on management and API nodes. * Improved access to partitioning information The *Note `ndb_desc': mysql-cluster-programs-ndb-desc. utility now provides additional information about the partitioning of data stored in MySQL Cluster. Beginning with MySQL Cluster NDB 6.3.32, the `--blob-info' option causes this program to include partition information for *Note `BLOB': blob. tables in its output. Beginning with MySQL Cluster NDB 6.3.33, the `--extra-node-info' option causes *Note `ndb_desc': mysql-cluster-programs-ndb-desc. to include information about data distribution (that is, which table fragments are stored on which data nodes). Each of these options also requires the use of the `--extra-partition-info' option. Information about partition-to-node mappings can also be obtained using the `Table::getFragmentNodes()' method, also added in MySQL Cluster NDB 6.3.33. * Replication attribute promotion and demotion Beginning with MySQL Cluster NDB 6.3.33, MySQL Cluster Replication supports attribute promotion and demotion when replicating between columns of different but similar types on the master and the slave. For example, it is possible to promote an *Note `INT': numeric-types. column on the master to a *Note `BIGINT': numeric-types. column on the slave, and to demote a *Note `TEXT': blob. column to a *Note `VARCHAR': char. column. The implementation of type demotion distinguishes between lossy and non-lossy type conversions, and their use on the slave can be controlled by setting the `slave_type_conversions' global server system variable. For more information, see *Note replication-features-attribute-promotion::. * Incompatible change in NDB API event reporting Beginning with MySQL Cluster NDB 6.3.34, DDL events are no longer reported on `Event' objects by default. Instead such event reporting must be enabled explicitly using the `Event::setReport()' method. For more information, see `Event::setReport()' (http://dev.mysql.com/doc/ndbapi/en/ndb-event-methods.html#ndb-event-setreport), and The `Event::EventReport' Type (http://dev.mysql.com/doc/ndbapi/en/ndb-event-types.html#ndb-event-eventreport). * Heartbeat ordering Beginning with MySQL Cluster NDB 6.3.35, it is possible to set a specific order for transmission of heartbeats between datat nodes, using the `HeartbeatOrder' data node configuration parameter introduced in this version. This parameter can be useful in situations where multiple data nodes are running on the same host and a temporary disruption in connectivity between hosts would otherwise cause the loss of a node group (and thus failure of the cluster). * Relaxed `ndb_restore' column comparison rules When restoring data, ndb_restore compares the attributes of a column for equality with the definition of the column in the target table. However, not all of these attributes need to be the same for *Note `ndb_restore': mysql-cluster-programs-ndb-restore. to be meaningful, safe and useful. Beginning with MySQL Cluster NDB 6.3.35, *Note `ndb_restore': mysql-cluster-programs-ndb-restore. automatically ignores differences in certain column attributes which do not necessarily have to match between the version of the column in a backup and the version of that column in the MySQL Cluster to which the column data is being restored. These attributes include the following: * `COLUMN_FORMAT' setting (`FIXED', `DYNAMIC', or `DEFAULT') * `STORAGE' setting (`MEMORY' or `DISK') * The default value * The distribution key In such cases, *Note `ndb_restore': mysql-cluster-programs-ndb-restore. reports any such differences to minimize any chance of user error. * `--add-drop-trigger' option for `mysqldump' Beginning with MySQL Cluster NDB 6.3.38, this option can be used to force all *Note `CREATE TRIGGER': create-trigger. statements in *Note `mysqldump': mysqldump. output to be preceded by a *Note `DROP TRIGGER IF EXISTS': drop-trigger. statement. * Skipping corrupted tables in `NDB' native backups Beginning with MySQL Cluster NDB 6.3.40, you can cause *Note `ndb_restore': mysql-cluster-programs-ndb-restore. to ignore tables that are corrupted due to missing blob parts tables by using the the `--skip-broken-objects' option. When this option is used, such tables are skipped, and the restoration of any remaining uncorrupted tables in the backup continues. * Restoring from a NDB native backup to a differently-named database MySQL Cluster NDB 6.3.41 adds a new `--rewrite-database' option to *Note `ndb_restore': mysql-cluster-programs-ndb-restore, which makes it possible to restore to a database having a different name from that of the database in the backup. The option can be used multiple times, and it is possible to restore from more than one source database in the backup to a single target database (although no protection against table or other object name collision is provided). See *Note mysql-cluster-programs-ndb-restore::, for more information. MySQL Cluster NDB 6.3 and later is also supported by MySQL Cluster Manager, which provides an advanced command-line interface that can simplify many complex MySQL Cluster management tasks. See MySQL(tm) Cluster Manager 1.1 User Manual (http://dev.mysql.com/doc/cluster-manager/en/index.html), for more information.  File: manual.info, Node: mysql-cluster-development-5-1-ndb-6-2, Next: mysql-cluster-development-5-1-ndb-6-1, Prev: mysql-cluster-development-5-1-ndb-6-3, Up: mysql-cluster-development 17.1.4.5 MySQL Cluster Development in MySQL Cluster NDB 6.2 ........................................................... The following list provides an overview of significant feature additions and changes made in MySQL Cluster NDB 6.2. All of the changes in this list are also available in MySQL Cluster NDB 6.3 . For more detailed information about all feature changes and bugfixes made in MySQL Cluster NDB 6.2, see *Note mysql-cluster-news-6-2::. * Enhanced backup status reporting Backup status reporting has been improved, aided in part by the introduction of a `BackupReportFrequency' configuration parameter. * Multiple cluster connections per SQL node A single MySQL server acting as a MySQL Cluster SQL node can employ multiple connections to the cluster using the `--ndb-cluster-connection-pool' startup option for *Note `mysqld': mysqld. This option is described in `MySQL Cluster-Related Command Options for *Note `mysqld': mysqld.: `--ndb-cluster-connection-pool' option'. * New data access interface The `NdbRecord' interface provides a new and simplified data handler for use in NDB API applications. * New reporting commands The new management client `REPORT BackupStatus' and `REPORT MemoryUsage' commands provide better access to information about the status of MySQL Cluster backups and how much memory is being used by MySQL Cluster for data and index storage. See *Note mysql-cluster-mgm-client-commands::, for more information about the `REPORT' commands. In addition, in-progress status reporting is provided by the *Note `ndb_restore': mysql-cluster-programs-ndb-restore. utility; see *Note mysql-cluster-programs-ndb-restore::. * Improved memory allocation and configuration Memory is now allocated by the *Note `NDB': mysql-cluster. kernel to tables on a page-by-page basis, which significantly reduces the memory overhead required for maintaining *Note `NDBCLUSTER': mysql-cluster. tables. In addition, the `MaxAllocate' configuration parameter now makes it possible to set the maximum size of the allocation unit used for table memory. * Choice of fixed-width or variable-width columns You can control whether fixed-width or variable-width storage is used for a given column of an *Note `NDB': mysql-cluster. table by employing of the `COLUMN_FORMAT' specifier as part of the column's definition in a *Note `CREATE TABLE': create-table. or *Note `ALTER TABLE': alter-table. statement. In addition, the ability to control whether a given column of an *Note `NDB': mysql-cluster. table is stored in memory or on disk, using the `STORAGE' specifier as part of the column's definition in a *Note `CREATE TABLE': create-table. or *Note `ALTER TABLE': alter-table. statement. For more information, see *Note create-table::, and *Note alter-table::. * Controlling management client connections The `--bind-address' cluster management server startup option makes it possible to restrict management client connections to *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. to a single host (IP address or host name) and port, which can make MySQL Cluster management operations more secure. For more information about this option, see *Note mysql-cluster-programs-ndb-mgmd::. * Micro-GCPs Due to a change in the protocol for handling of global checkpoints (GCPs handled in this manner sometimes being referred to as `micro-GCPs'), it is now possible to control how often the GCI number is updated, and how often global checkpoints are written to disk, using the `TimeBetweenEpochs' and `TimeBetweenEpochsTimeout' configuration parameters. This improves the reliability and performance of MySQL Cluster Replication. * Core online schema change support Support for the online *Note `ALTER TABLE': alter-table. operations `ADD COLUMN', `ADD INDEX', and *Note `DROP INDEX': drop-index. is available. When the `ONLINE' keyword is used, the *Note `ALTER TABLE': alter-table. is noncopying, which means that indexes do not have to be re-created, which provides these benefits: * Single user mode is no longer required for *Note `ALTER TABLE': alter-table. operations that can be performed online. * Transactions can continue during *Note `ALTER TABLE': alter-table. operations that can be performed online. * Tables being altered online are not locked against access by other SQL nodes. However, such tables are locked against other operations on the _same_ SQL node for the duration of the *Note `ALTER TABLE': alter-table. We are working to overcome this limitation in a future MySQL Cluster release. Online *Note `CREATE INDEX': create-index. and *Note `DROP INDEX': drop-index. statements are also supported. Online changes can be suppressed using the `OFFLINE' key word. See *Note alter-table::, *Note create-index::, and *Note drop-index::, for more detailed information. * `mysql.ndb_binlog_index' improvements More information has been added to the `mysql.ndb_binlog_index' table so that it is possible to determine which originating epochs have been applied inside an epoch. This is particularly useful for 3-way replication. See *Note mysql-cluster-replication-schema::, for more information. * Epoch lag control The `MaxBufferedEpochs' data node configuration parameter provides a means to control the maximum number of unprocessed epochs by which a subscribing node can lag. Subscribers which exceed this number are disconnected and forced to reconnect. * Fully automatic database discovery It is no longer a requirement for database autodiscovery that an SQL node already be connected to the cluster at the time that a database is created on another SQL node, or for a *Note `CREATE DATABASE': create-database. or *Note `CREATE SCHEMA': create-database. statement to be issued on the new SQL node after it joins the cluster. * Multiple data node processes per host In earlier MySQL Cluster release series, we did not support MySQL Cluster deployments in production where more than one *Note `ndbd': mysql-cluster-programs-ndbd. process was run on a single physical machine. However, beginning with MySQL Cluster NDB 6.2.0, you can use multiple data node processes on a single host. *Note*: A multi-threaded version of *Note `ndbd': mysql-cluster-programs-ndbd. tailored for use on hosts with multiple CPUs or cores was introduced in MySQL Cluster NDB 7.0. See *Note mysql-cluster-development-5-1-ndb-7-0::, and *Note mysql-cluster-programs-ndbmtd::, for more information. * Improved Disk Data file system configuration As of MySQL Cluster NDB 6.2.17, you can specify default locations for MySQL Cluster Disk Data data files and undo log files using the data node configuration parameters `FileSystemPathDD', `FileSystemPathDataFiles', and `FileSystemPathUndoFiles'. This eliminates the need to use symbolic links to place Disk Data files separately from other files in data node file systems to improve Disk Data performance. For more information, see *Note mysql-cluster-ndbd-disk-data-filesystem-parameters::. * Automatic creation of Disk Data log file groups and tablespaces Beginning with MySQL Cluster NDB 6.2.17, using the data node configuration parameters `InitialLogFileGroup' and `InitialTablespace', you can cause the creation of a MySQL Cluster Disk Data log file group, tablespace, or both, when the cluster is first started. When using these parameters, no SQL statements are required to create these Disk Data objects. * Improved access to partitioning information The *Note `ndb_desc': mysql-cluster-programs-ndb-desc. utility now provides additional information about the partitioning of data stored in MySQL Cluster. Beginning with MySQL Cluster NDB 6.2.19, the `--extra-node-info' option causes *Note `ndb_desc': mysql-cluster-programs-ndb-desc. to include information about data distribution (that is, which table fragments are stored on which data nodes). This option also requires the use of the `--extra-partition-info' option. Information about partition-to-node mappings can also be obtained using the `Table::getFragmentNodes()' method, also added in MySQL Cluster NDB 6.2.19. * New `CHANGE MASTER TO' option for circular replication Beginning with MySQL Cluster NDB 6.2.19, the *Note `CHANGE MASTER TO': change-master-to. statement supports an `IGNORE_SERVER_IDS' option which takes a comma-separated list of server IDs and causes events originating from the corresponding servers to be ignored. (Log rotation and log deletion events are preserved.) See *Note change-master-to::, as well as *Note show-slave-status::, for more information.  File: manual.info, Node: mysql-cluster-development-5-1-ndb-6-1, Next: mysql-cluster-development-5-1, Prev: mysql-cluster-development-5-1-ndb-6-2, Up: mysql-cluster-development 17.1.4.6 MySQL Cluster Development in MySQL Cluster NDB 6.1 ........................................................... The following list provides an overview of significant feature additions and changes made in MySQL Cluster NDB 6.1. All of the changes in this list are also available in MySQL Cluster NDB 6.2 and 6.3 releases. For detailed information about all changes made in MySQL Cluster NDB 6.1, see *Note mysql-cluster-news-6-1::. * Increased number of cluster nodes The maximum number of all nodes in a MySQL Cluster has been increased to 255. For more information, see *Note mysql-cluster-limitations-multiple-nodes::. * Disabling arbitration It is now possible to disable arbitration by setting `ArbitrationRank=0' on all cluster management and SQL nodes. For more information, see `Defining the Management Server: `ArbitrationRank'' and `Defining SQL and Other API Nodes: `ArbitrationRank''. * Additional `DUMP' commands New management client `DUMP' commands provide help with tracking transactions, scan operations, and locks. See *Note mysql-cluster-mgm-client-commands::, and `DUMP' Commands (http://dev.mysql.com/doc/ndbapi/en/ndb-internals-dump-commands.html), for more information. * Faster Disk Data backups Improvements in backups of Disk Data tables can yield a 10 to 15% increase in backup speed of Disk Data tables. * Batched slave updates Batching of updates on cluster replication slaves, enabled using the `--slave-allow-batching' option for *Note `mysqld': mysqld, increases replication efficiency. For more information, see *Note mysql-cluster-replication-starting::.  File: manual.info, Node: mysql-cluster-development-5-1, Prev: mysql-cluster-development-5-1-ndb-6-1, Up: mysql-cluster-development 17.1.4.7 Development History of MySQL Cluster in MySQL 5.1 .......................................................... A number of features for MySQL Cluster were implemented in MySQL 5.1 through MySQL 5.1.23, when support for MySQL Cluster was moved to MySQL Cluster NDB. All of the features in the following list are also available in all MySQL Cluster NDB (6.1 and later) releases. * Integration of MySQL Cluster into MySQL Replication MySQL Cluster Replication makes it possible to replicate from one MySQL Cluster to another. Updates on any SQL node (MySQL server) in the cluster acting as the master are replicated to the slave cluster; the state of the slave side remains consistent with the cluster acting as the master. This is sometimes referred to as _asynchronous replication_ between clusters, providing _geographic redundancy_. It is also possible to replicate from a MySQL Cluster acting as the master to a standalone MySQL server acting as the slave, or from a standalone MySQL master server to to a slave cluster; in either of these cases, the standalone MySQL server uses a storage engine other than *Note `NDBCLUSTER': mysql-cluster. Multi-master replication setups such as circular replication are also supported. See *Note mysql-cluster-replication::. * Support for storage of rows on disk Storage of *Note `NDBCLUSTER': mysql-cluster. table data on disk is now supported. Indexed columns, including the primary key hash index, must still be stored in RAM; however, all other columns can be stored on disk. See *Note mysql-cluster-disk-data::. * Variable-size columns In MySQL 5.0, an *Note `NDBCLUSTER': mysql-cluster. table column defined as `VARCHAR(255)' used 260 bytes of storage independent of what was stored in any particular record. In MySQL 5.1 Cluster tables, only the portion of the column actually taken up by the record is stored. This makes possible a significant reduction in space requirements for such columns as compared to previous release series--by a factor of up to 5 in many cases. * User-defined partitioning Users can define partitions based on columns that are part of the primary key. It is possible to partition *Note `NDB': mysql-cluster. tables based on `KEY' and `LINEAR KEY' schemes. This feature is also available for many other MySQL storage engines, which support additional partitioning types that are not available with *Note `NDBCLUSTER': mysql-cluster. tables. For additional general information about user-defined partitioning in MySQL 5.1, see *Note partitioning::. Specifics of partitioning types are discussed in *Note partitioning-types::. The MySQL Server can also determine whether it is possible to `prune away' some of the partitions from the `WHERE' clause, which can greatly speed up some queries. See *Note partitioning-pruning::, for information about designing tables and queries to take advantage of partition pruning. * Autodiscovery of table schema changes In MySQL 5.0, it was necessary to issue a *Note `FLUSH TABLES': flush. statement or a `dummy' *Note `SELECT': select. for new *Note `NDBCLUSTER': mysql-cluster. tables or changes made to schemas of existing *Note `NDBCLUSTER': mysql-cluster. tables on one SQL node to be visible on the cluster's other SQL nodes. In MySQL 5.1, this is no longer necessary; new Cluster tables and changes in the definitions of existing *Note `NDBCLUSTER': mysql-cluster. tables made on one SQL node are immediately visible to all SQL nodes connected to the cluster. *Note*: When creating a new database, it is still necessary in MySQL 5.1 to issue a *Note `CREATE DATABASE': create-database. or *Note `CREATE SCHEMA': create-database. statement on each SQL node in the cluster. * Distribution awareness (NDB API) _Distribution awareness_ is a mechanism by which the best data node is automatically selected to be queried for information. (Conceptually, it is similar in some ways to partition pruning (see *Note partitioning-pruning::). To take advantage of distribution awareness, you should do the following: 1. Determine which table column is most likely to be used for finding matching records. 2. Make this column part of the table's primary key. 3. Explicitly partition the table by `KEY', using this column as the table' partitioning key. Following these steps causes records with the same value for the partitioning column to be stored on the same partition (that is, in the same node group). When reading data, transactions are begun on the data node actually having the desired rows instead of this node being determined by the usual round-robin mechanism. *Important*: To see a measureable impact on performance, the cluster must have at least four data nodes, since, with only two data nodes, both data nodes have exactly the same data. Using distribution awareness can yield performance increase of as great as 45% when using four data nodes, and possibly more when using a greater number of data nodes. *Note*: In mainline MySQL 5.1 releases, distribution awareness was supported only when using the NDB API; support was added for SQL and API nodes in MySQL Cluster NDB 6.3 (see *Note mysql-cluster-development-5-1-ndb-6-3::, which includes an example showing how to create a table to take advantage of distribution awareness). See *Note mysql-cluster-limitations-resolved::, for more information.  File: manual.info, Node: mysql-cluster-compared, Next: mysql-cluster-limitations, Prev: mysql-cluster-development, Up: mysql-cluster-overview 17.1.5 MySQL Server using `InnoDB' Compared with MySQL Cluster -------------------------------------------------------------- * Menu: * mysql-cluster-ndb-innodb-engines:: Differences Between the `NDB' and `InnoDB' Storage Engines * mysql-cluster-ndb-innodb-workloads:: `NDB' and `InnoDB' Workloads * mysql-cluster-ndb-innodb-usage:: `NDB' and `InnoDB' Feature Usage Summary MySQL Server offers a number of choices in storage engines. Since both *Note `NDBCLUSTER': mysql-cluster. and *Note `InnoDB': innodb-storage-engine. can serve as transactional MySQL storage engines, users of MySQL Server sometimes become interested in MySQL Cluster. They see *Note `NDB': mysql-cluster. as a possible alternative or upgrade to the default *Note `InnoDB': innodb-storage-engine. storage engine in MySQL 5.5. While *Note `NDB': mysql-cluster. and *Note `InnoDB': innodb-storage-engine. share common characteristics, there are differences in architecture and implementation, so that some existing MySQL Server applications and usage scenarios can be a good fit for MySQL Cluster, but not all of them. In this section, we discuss and compare some characteristics of the *Note `NDB': mysql-cluster. storage engine used by MySQL Cluster with *Note `InnoDB': innodb-storage-engine. used in MySQL 5.1 and MySQL 5.5. The next few sections provide a technical comparison. In many instances, decisions about when and where to use MySQL Cluster must be made on a case-by-case basis, taking all factors into consideration. While it is beyond the scope of this documentation to provide specifics for every conceivable usage scenario, we also attempt to offer some very general guidance on the relative suitability of some common types of applications for *Note `NDB': mysql-cluster. as opposed to *Note `InnoDB': innodb-storage-engine. backends. While it is possible to use *Note `InnoDB': innodb-storage-engine. tables with MySQL Cluster, such tables are not clustered. It is also not always possible to use the latest MySQL Cluster and *Note `InnoDB': innodb-storage-engine. features and enhancements together due to availability issues. Currently, the latest MySQL Cluster NDB 7.1 releases use a *Note `mysqld': mysqld. based on MySQL 5.1; while the most recent *Note `InnoDB': innodb-storage-engine. enhancements are available only in MySQL Server 5.5, where MySQL Cluster is not currently supported. It is also not possible to use programs or libraries from a MySQL Cluster NDB 6.x or MySQL Cluster NDB 7.x distribution with MySQL Server 5.1 or MySQL Server 5.5, or the reverse. While it is also true that some types of common business applications can be run either on MySQL Cluster or on MySQL Server (most likely using the *Note `InnoDB': innodb-storage-engine. storage engine), there are some important architectural and implementation differences. *Note mysql-cluster-ndb-innodb-engines::, provides a summary of the these differences. Due to the differences, some usage scenarios are clearly more suitable for one engine or the other; see *Note mysql-cluster-ndb-innodb-workloads::. This in turn has an impact on the types of applications that better suited for use with *Note `NDB': mysql-cluster. or *Note `InnoDB': innodb-storage-engine. See *Note mysql-cluster-ndb-innodb-usage::, for a comparison of the relative suitability of each for use in common types of database applications. For information about the relative characteristics of the *Note `NDB': mysql-cluster. and *Note `MEMORY': memory-storage-engine. storage engines, see *Note memory-compared-cluster::. See *Note storage-engines::, for additional information about MySQL storage engines.  File: manual.info, Node: mysql-cluster-ndb-innodb-engines, Next: mysql-cluster-ndb-innodb-workloads, Prev: mysql-cluster-compared, Up: mysql-cluster-compared 17.1.5.1 Differences Between the `NDB' and `InnoDB' Storage Engines ................................................................... The MySQL Cluster *Note `NDB': mysql-cluster. storage engine is implemented using a distributed, shared-nothing architecture, which causes it to behave differently from *Note `InnoDB': innodb-storage-engine. in a number of ways. For those unaccustomed to working with *Note `NDB': mysql-cluster, unexpected behaviors can arise due to its distributed nature with regard to transactions, foreign keys, joins, and other characteristics. These are shown in the following table: Feature *Note `InnoDB': MySQL Cluster (*Note innodb-storage-engine. `NDB': mysql-cluster.) _MySQL Server 5.5 (in latest MySQL 5.1 (SQL nodes Availability_ 5.5 GA release) currently based on MySQL 5.1.51 GA) _`InnoDB' Availability _ *Note `InnoDB': _NDB 6.3, 7.0_: *Note innodb-storage-engine. `InnoDB': 1.1 plugin innodb-storage-engine. storage engine _NDB 7.1_: *Note `InnoDB': innodb-storage-engine. 1.0 plugin support, as of MySQL Cluster NDB 7.1.9a _Storage Limits_ 64TB 2TB (Practical upper limit for database size) _Foreign Keys_ Yes No (Foreign keys ignored, as with *Note `MyISAM': myisam-storage-engine.) _Transactions_ All standard types Only `READ COMMITTED' supported _MVCC Non-Blocking Yes No Reads_ (Read concurrency without locks) _Multi-Table Join Good Poor Performance_ (Push-down joins can improve MySQL Cluster performance, but *Note `InnoDB': innodb-storage-engine. provides higher throughput) _Data Compression_ Yes No (MySQL Cluster checkpoint and backup files can be compressed) _Large Row Support (> Supported for *Note Supported for *Note 8K)_ `VARBINARY': `BLOB': blob. and *Note binary-varbinary, `TEXT': blob. columns `VARCHAR', *Note only `BLOB': blob, and *Note `TEXT': blob. columns (Using these types to store very large amounts of data can lower MySQL Cluster performance) _Virtualization_ Yes No (Can be deployed on (Not supported in both physical and virtual environments) virtual infrastructure) _Minimum Number of _2_: 1 active, 1 passive _3_: 2 data nodes, 1 Physical Hosts for management node Redundancy _ _Availability (HA)_ No Yes (99.999%) _Node Failure Recovery Requires additional Automatic and Failover_ software (Key element in MySQL Cluster architecture) _Time for Node Failure 30 seconds to several < 1 second Recovery_ hours _Real-Time Performance_ No Yes (Low latency) _In-Memory Storage_ No Yes (Some data can optionally be stored on disk; both in-memory and disk data storage are durable) _Direct (non-SQL) API No Yes Access to Storage Engine _ (Faster access possible when bypassing SQL interface to data) _Scalability_ Poor Good (Requires (Data already application-level partitioned by MySQL partitioning) Cluster; schema and query optimization required to maximize scaling of writes) _Concurrent and Not supported Up to 48 writers, Parallel Writes_ optimized for concurrent writes (MySQL Cluster supports up to 48 data nodes for processing, with 24 nodes for storage, due to requirements for two-fold redundancy) _Conflict Detection and No Yes Resolution (Multiple Replication Masters)_ (True active-active geographic replication, in which each application node can read or write to its own local database) _Hash Indexes_ No Yes (Can provide fast access to key/value data)  File: manual.info, Node: mysql-cluster-ndb-innodb-workloads, Next: mysql-cluster-ndb-innodb-usage, Prev: mysql-cluster-ndb-innodb-engines, Up: mysql-cluster-compared 17.1.5.2 `NDB' and `InnoDB' Workloads ..................................... MySQL Cluster has a range of unique attributes that make it ideal to serve applications requiring high availability, fast failover, high throughput, and low latency. Due to its real-time nature, distributed architecture, and multi-node implementation, MySQL Cluster also has specific constraints that may keep some workloads from performing well. A number of major differences in behavior between the *Note `NDB': mysql-cluster. and *Note `InnoDB': innodb-storage-engine. storage engines with regard to some common types of database-driven application workloads are shown in the following table:
 Workload *Note `InnoDB': MySQL Cluster (*Note innodb-storage-engine. `NDB': mysql-cluster.) _In-Network Telecoms No Yes Applications (HLR, HSS, SDP)_ _Packaged Applications_ Yes Access should be mostly by primary key _Custom Applications_ Yes Yes _OLTP Applications_ Yes Yes _DSS Applications (data Yes No marts, analytics)_ _Content Management_ Yes Limited support _Web Session Management_ Yes Yes _E-Commerce Yes Yes Applications_ _User Profile Yes Yes Management, AAA Protocol_  File: manual.info, Node: mysql-cluster-ndb-innodb-usage, Prev: mysql-cluster-ndb-innodb-workloads, Up: mysql-cluster-compared 17.1.5.3 `NDB' and `InnoDB' Feature Usage Summary ................................................. When comparing application feature requirements to the capabilities of *Note `InnoDB': innodb-storage-engine. with *Note `NDB': mysql-cluster, some are clearly more compatible with one storage engine than the other. For example, since *Note `NDB': mysql-cluster. does not support foreign keys, an application that requires them and cannot be re-engineered to remove this requirement is likely not to be a good match for MySQL Cluster. The following table shows required supported features for applications according to which of these two storage engines each of them is usually better suited: Application requirements better Application requirements better supported with *Note `InnoDB': supported with *Note `NDB': innodb-storage-engine. mysql-cluster. * Foreign keys * Real-time concurrency * Large or complex joins * High availability, high-speed failover * Very large datastores or transactions * Fast low-level APIs (see MySQL Cluster APIs: Overview and * Transactions other than `READ Concepts COMMITTED' (http://dev.mysql.com/doc/ndbapi/en/mysql-cluster-api-overview.html)) * Preference for SQL interface * Primary-key lookups, key/value to data data * Limited use of *Note `BLOB': blob. columns  File: manual.info, Node: mysql-cluster-limitations, Prev: mysql-cluster-compared, Up: mysql-cluster-overview 17.1.6 Known Limitations of MySQL Cluster ----------------------------------------- * Menu: * mysql-cluster-limitations-syntax:: Noncompliance with SQL Syntax in MySQL Cluster * mysql-cluster-limitations-limits:: Limits and Differences of MySQL Cluster from Standard MySQL Limits * mysql-cluster-limitations-transactions:: Limits Relating to Transaction Handling in MySQL Cluster * mysql-cluster-limitations-error-handling:: MySQL Cluster Error Handling * mysql-cluster-limitations-database-objects:: Limits Associated with Database Objects in MySQL Cluster * mysql-cluster-limitations-unsupported:: Unsupported or Missing Features in MySQL Cluster * mysql-cluster-limitations-performance:: Limitations Relating to Performance in MySQL Cluster * mysql-cluster-limitations-exclusive-to-cluster:: Issues Exclusive to MySQL Cluster * mysql-cluster-limitations-disk-data:: Limitations Relating to MySQL Cluster Disk Data Storage * mysql-cluster-limitations-multiple-nodes:: Limitations Relating to Multiple MySQL Cluster Nodes * mysql-cluster-limitations-resolved:: Previous MySQL Cluster Issues Resolved in MySQL 5.1, MySQL Cluster NDB 6.x, and MySQL Cluster NDB 7.x In the sections that follow, we discuss known limitations in current releases of MySQL Cluster as compared with the features available when using the `MyISAM' and `InnoDB' storage engines. If you check the `Cluster' category in the MySQL bugs database at `http://bugs.mysql.com', you can find known bugs in the following categories under `MySQL Server:' in the MySQL bugs database at `http://bugs.mysql.com', which we intend to correct in upcoming releases of MySQL Cluster: * MySQL Cluster * Cluster Direct API (NDBAPI) * Cluster Disk Data * Cluster Replication * ClusterJ This information is intended to be complete with respect to the conditions just set forth. You can report any discrepancies that you encounter to the MySQL bugs database using the instructions given in *Note bug-reports::. If we do not plan to fix the problem in MySQL Cluster NDB 6.X or 7.X, we will add it to the list. See *Note mysql-cluster-limitations-resolved:: for a list of issues in MySQL Cluster in MySQL 5.0 that have been resolved in the current version. *Note*: Limitations and other issues specific to MySQL Cluster Replication are described in *Note mysql-cluster-replication-issues::.  File: manual.info, Node: mysql-cluster-limitations-syntax, Next: mysql-cluster-limitations-limits, Prev: mysql-cluster-limitations, Up: mysql-cluster-limitations 17.1.6.1 Noncompliance with SQL Syntax in MySQL Cluster ....................................................... Some SQL statements relating to certain MySQL features produce errors when used with *Note `NDB': mysql-cluster. tables, as described in the following list: * Temporary tables Temporary tables are not supported. Trying either to create a temporary table that uses the *Note `NDB': mysql-cluster. storage engine or to alter an existing temporary table to use *Note `NDB': mysql-cluster. fails with the error `Table storage engine 'ndbcluster' does not support the create option 'TEMPORARY''. * Indexes and keys in `NDB' tables Keys and indexes on MySQL Cluster tables are subject to the following limitations: * Column width Attempting to create an index on an `NDB' table column whose width is greater than 3072 bytes succeeds, but only the first 3072 bytes are actually used for the index. In such cases, a warning `Specified key was too long; max key length is 3072 bytes' is issued, and a *Note `SHOW CREATE TABLE': show-create-table. statement shows the length of the index as 3072. * `TEXT' and `BLOB' columns You cannot create indexes on *Note `NDB': mysql-cluster. table columns that use any of the *Note `TEXT': blob. or *Note `BLOB': blob. data types. * `FULLTEXT' indexes The *Note `NDB': mysql-cluster. storage engine does not support `FULLTEXT' indexes, which are possible for `MyISAM' tables only. However, you can create indexes on *Note `VARCHAR': char. columns of *Note `NDB': mysql-cluster. tables. * `USING HASH' keys and `NULL' Using nullable columns in unique keys and primary keys means that queries using these columns are handled as full table scans. To work around this issue, make the column `NOT NULL', or re-create the index without the `USING HASH' option. * Prefixes There are no prefix indexes; only entire columns can be indexed. (The size of an `NDB' column index is always the same as the width of the column in bytes, up to and including 3072 bytes, as described earlier in this section. Also see *Note mysql-cluster-limitations-unsupported::, for additional information.) * `BIT' columns A *Note `BIT': numeric-types. column cannot be a primary key, unique key, or index, nor can it be part of a composite primary key, unique key, or index. * `AUTO_INCREMENT' columns Like other MySQL storage engines, the *Note `NDB': mysql-cluster. storage engine can handle a maximum of one `AUTO_INCREMENT' column per table. However, in the case of a Cluster table with no explicit primary key, an `AUTO_INCREMENT' column is automatically defined and used as a `hidden' primary key. For this reason, you cannot define a table that has an explicit `AUTO_INCREMENT' column unless that column is also declared using the `PRIMARY KEY' option. Attempting to create a table with an `AUTO_INCREMENT' column that is not the table's primary key, and using the *Note `NDB': mysql-cluster. storage engine, fails with an error. * MySQL Cluster and geometry data types Geometry data types (`WKT' and `WKB') are supported in *Note `NDB': mysql-cluster. tables in MySQL 5.1 (including MySQL Cluster NDB 6.X and 7.X through 7.1). However, spatial indexes are not supported. * Character sets and binary log files Currently, the `ndb_apply_status' and `ndb_binlog_index' tables are created using the `latin1' (ASCII) character set. Because names of binary logs are recorded in this table, binary log files named using non-Latin characters are not referenced correctly in these tables. This is a known issue, which we are working to fix. (Bug#50226) To work around this problem, use only Latin-1 characters when naming binary log files or setting any the `--basedir', `--log-bin', or `--log-bin-index' options. * Creating `NDBCLUSTER' tables with user-defined partitioning Support for user-defined partitioning for MySQL Cluster in MySQL 5.1 (including MySQL Cluster NDB 6.X and 7.X through 7.1) is restricted to [`LINEAR'] `KEY' partitioning. Beginning with MySQL 5.1.12, using any other partitioning type with `ENGINE=NDB' or `ENGINE=NDBCLUSTER' in a *Note `CREATE TABLE': create-table. statement results in an error. Default partitioning scheme As of MySQL 5.1.6, all MySQL Cluster tables are by default partitioned by `KEY' using the table's primary key as the partitioning key. If no primary key is explicitly set for the table, the `hidden' primary key automatically created by the *Note `NDBCLUSTER': mysql-cluster. storage engine is used instead. For additional discussion of these and related issues, see *Note partitioning-key::. Beginning with MySQL Cluster NDB 6.2.18, MySQL Cluster NDB 6.3.25, and MySQL Cluster NDB 7.0.6, *Note `CREATE TABLE': create-table. and *Note `ALTER TABLE': alter-table. statements that would cause a user-partitioned *Note `NDBCLUSTER': mysql-cluster. table not to meet either or both of the following two requirements are not permitted, and fail with an error (Bug#40709): 1. The table must have an explicit primary key. 2. All columns listed in the table's partitioning expression must be part of the primary key. Exception If a user-partitioned *Note `NDBCLUSTER': mysql-cluster. table is created using an empty column-list (that is, using `PARTITION BY [LINEAR] KEY()'), then no explicit primary key is required. Maximum number of partitions for `NDBCLUSTER' tables The maximum number of partitions that can defined for a *Note `NDBCLUSTER': mysql-cluster. table when employing user-defined partitioning is 8 per node group. (See *Note mysql-cluster-nodes-groups::, for more information about MySQL Cluster node groups. `DROP PARTITION' not supported It is not possible to drop partitions from *Note `NDB': mysql-cluster. tables using `ALTER TABLE ... DROP PARTITION'. The other partitioning extensions to *Note `ALTER TABLE': alter-table.--`ADD PARTITION', `REORGANIZE PARTITION', and `COALESCE PARTITION'--are supported for Cluster tables, but use copying and so are not optimized. See *Note partitioning-management-range-list:: and *Note alter-table::. * Row-based replication When using row-based replication with MySQL Cluster, binary logging cannot be disabled. That is, the *Note `NDB': mysql-cluster. storage engine ignores the value of `sql_log_bin'. (Bug#16680)  File: manual.info, Node: mysql-cluster-limitations-limits, Next: mysql-cluster-limitations-transactions, Prev: mysql-cluster-limitations-syntax, Up: mysql-cluster-limitations 17.1.6.2 Limits and Differences of MySQL Cluster from Standard MySQL Limits ........................................................................... In this section, we list limits found in MySQL Cluster that either differ from limits found in, or that are not found in, standard MySQL. Memory usage and recovery Memory consumed when data is inserted into an *Note `NDB': mysql-cluster. table is not automatically recovered when deleted, as it is with other storage engines. Instead, the following rules hold true: * A *Note `DELETE': delete. statement on an *Note `NDB': mysql-cluster. table makes the memory formerly used by the deleted rows available for re-use by inserts on the same table only. However, this memory can be made available for general re-use by performing a rolling restart of the cluster. See *Note mysql-cluster-rolling-restart::. Beginning with MySQL Cluster NDB 6.3.7, this limitation can be overcome using *Note `OPTIMIZE TABLE': optimize-table. See *Note mysql-cluster-limitations-resolved::, for more information. * A *Note `DROP TABLE': drop-table. or *Note `TRUNCATE TABLE': truncate-table. operation on an *Note `NDB': mysql-cluster. table frees the memory that was used by this table for re-use by any *Note `NDB': mysql-cluster. table, either by the same table or by another *Note `NDB': mysql-cluster. table. *Note*: Recall that *Note `TRUNCATE TABLE': truncate-table. drops and re-creates the table. See *Note truncate-table::. * Limits imposed by the cluster's configuration A number of hard limits exist which are configurable, but available main memory in the cluster sets limits. See the complete list of configuration parameters in *Note mysql-cluster-config-file::. Most configuration parameters can be upgraded online. These hard limits include: * Database memory size and index memory size (`DataMemory' and `IndexMemory', respectively). `DataMemory' is allocated as 32KB pages. As each `DataMemory' page is used, it is assigned to a specific table; once allocated, this memory cannot be freed except by dropping the table. See *Note mysql-cluster-ndbd-definition::, for more information. * The maximum number of operations that can be performed per transaction is set using the configuration parameters `MaxNoOfConcurrentOperations' and `MaxNoOfLocalOperations'. *Note*: Bulk loading, *Note `TRUNCATE TABLE': truncate-table, and *Note `ALTER TABLE': alter-table. are handled as special cases by running multiple transactions, and so are not subject to this limitation. * Different limits related to tables and indexes. For example, the maximum number of ordered indexes in the cluster is determined by `MaxNoOfOrderedIndexes', and the maximum number of ordered indexes per table is 16. * Node and data object maximums The following limits apply to numbers of cluster nodes and metadata objects: * The maximum number of data nodes is 48. A data node must have a node ID in the range of 1 to 48, inclusive. (Previous to MySQL Cluster NDB 6.1.1, management and API nodes were restricted to the range 1 to 63 inclusive as a node ID; starting with MySQL Cluster NDB 6.1.1, management and API nodes may use node IDs in the range 1 to 255, inclusive.) * Prior to MySQL Cluster NDB 6.1.1, the total maximum number of nodes in a MySQL Cluster was 63. Beginning with MySQL Cluster NDB 6.1.1, the total maximum number of nodes in a MySQL Cluster is 255. In either case, this number includes all SQL nodes (MySQL Servers), API nodes (applications accessing the cluster other than MySQL servers), data nodes, and management servers. * The maximum number of metadata objects in current versions of MySQL Cluster is 20320. This limit is hard-coded. See *Note mysql-cluster-limitations-resolved::, for more information.  File: manual.info, Node: mysql-cluster-limitations-transactions, Next: mysql-cluster-limitations-error-handling, Prev: mysql-cluster-limitations-limits, Up: mysql-cluster-limitations 17.1.6.3 Limits Relating to Transaction Handling in MySQL Cluster ................................................................. A number of limitations exist in MySQL Cluster with regard to the handling of transactions. These include the following: * Transaction isolation level The *Note `NDBCLUSTER': mysql-cluster. storage engine supports only the `READ COMMITTED' transaction isolation level. (`InnoDB', for example, supports `READ COMMITTED', `READ UNCOMMITTED', `REPEATABLE READ', and `SERIALIZABLE'.) See *Note mysql-cluster-backup-troubleshooting::, for information on how this can affect backing up and restoring Cluster databases.) * Transactions and `BLOB' or `TEXT' columns *Note `NDBCLUSTER': mysql-cluster. stores only part of a column value that uses any of MySQL's *Note `BLOB': blob. or *Note `TEXT': blob. data types in the table visible to MySQL; the remainder of the *Note `BLOB': blob. or *Note `TEXT': blob. is stored in a separate internal table that is not accessible to MySQL. This gives rise to two related issues of which you should be aware whenever executing *Note `SELECT': select. statements on tables that contain columns of these types: 1. For any *Note `SELECT': select. from a MySQL Cluster table: If the *Note `SELECT': select. includes a *Note `BLOB': blob. or *Note `TEXT': blob. column, the `READ COMMITTED' transaction isolation level is converted to a read with read lock. This is done to guarantee consistency. 2. Prior to MySQL Cluster NDB 7.0.12, for any *Note `SELECT': select. which used a primary key lookup or unique key lookup to retrieve any columns that used any of the *Note `BLOB': blob. or *Note `TEXT': blob. data types and that was executed within a transaction, a shared read lock was held on the table for the duration of the transaction--that is, until the transaction was either committed or aborted. In MySQL Cluster NDB 7.0.12 and later, for primary key lookups, the lock is released as soon as all *Note `BLOB': blob. or *Note `TEXT': blob. data has been read. (Bug#49190) However, for unique key lookups, the shared lock continues to be held for the lifetime of the transaction. This issue does not occur for queries that use index or table scans, even against *Note `NDB': mysql-cluster. tables having *Note `BLOB': blob. or *Note `TEXT': blob. columns. For example, consider the table `t' defined by the following *Note `CREATE TABLE': create-table. statement: CREATE TABLE t ( a INT NOT NULL AUTO_INCREMENT PRIMARY KEY, b INT NOT NULL, c INT NOT NULL, d TEXT, INDEX i(b), UNIQUE KEY u(c) ) ENGINE = NDB, Either of the following queries on `t' causes a shared read lock, because the first query uses a primary key lookup and the second uses a unique key lookup: SELECT * FROM t WHERE a = 1; SELECT * FROM t WHERE c = 1; However, none of the four queries shown here causes a shared read lock: SELECT * FROM t WHERE b 1; SELECT * FROM t WHERE d = '1'; SELECT * FROM t; SELECT b,c WHERE a = 1; This is because, of these four queries, the first uses an index scan, the second and third use table scans, and the fourth, while using a primary key lookup, does not retrieve the value of any *Note `BLOB': blob. or *Note `TEXT': blob. columns. You can help minimize issues with shared read locks by avoiding queries that use unique key lookups (or primary key lookups in MySQL Cluster NDB 7.0.11 and earlier) that retrieve *Note `BLOB': blob. or *Note `TEXT': blob. columns, or, in cases where such queries are not avoidable, by committing transactions as soon as possible afterward. * Rollbacks There are no partial transactions, and no partial rollbacks of transactions. A duplicate key or similar error causes the entire transaction to be rolled back. This behavior differs from that of other transactional storage engines such as *Note `InnoDB': innodb-storage-engine. that may roll back individual statements. * Transactions and memory usage As noted elsewhere in this chapter, MySQL Cluster does not handle large transactions well; it is better to perform a number of small transactions with a few operations each than to attempt a single large transaction containing a great many operations. Among other considerations, large transactions require very large amounts of memory. Because of this, the transactional behavior of a number of MySQL statements is effected as described in the following list: * *Note `TRUNCATE TABLE': truncate-table. is not transactional when used on *Note `NDB': mysql-cluster. tables. If a *Note `TRUNCATE TABLE': truncate-table. fails to empty the table, then it must be re-run until it is successful. * `DELETE FROM' (even with no `WHERE' clause) _is_ transactional. For tables containing a great many rows, you may find that performance is improved by using several `DELETE FROM ... LIMIT ...' statements to `chunk' the delete operation. If your objective is to empty the table, then you may wish to use *Note `TRUNCATE TABLE': truncate-table. instead. * `LOAD DATA' statements *Note `LOAD DATA INFILE': load-data. is not transactional when used on *Note `NDB': mysql-cluster. tables. *Important*: When executing a *Note `LOAD DATA INFILE': load-data. statement, the *Note `NDB': mysql-cluster. engine performs commits at irregular intervals that enable better utilization of the communication network. It is not possible to know ahead of time when such commits take place. *Note `LOAD DATA FROM MASTER': load-data-from-master. is not supported in MySQL Cluster. * `ALTER TABLE' and transactions When copying an *Note `NDB': mysql-cluster. table as part of an *Note `ALTER TABLE': alter-table, the creation of the copy is nontransactional. (In any case, this operation is rolled back when the copy is deleted.) * Transactions and the `COUNT()' function When using MySQL Cluster Replication, it is not possible to guarantee the transactional consistency of the `COUNT()' function on the slave. In other words, when performing on the master a series of statements (*Note `INSERT': insert, *Note `DELETE': delete, or both) that changes the number of rows in a table within a single transaction, executing `SELECT COUNT(*) FROM TABLE' queries on the slave may yield intermediate results. This is due to the fact that `SELECT COUNT(...)' may perform dirty reads, and is not a bug in the *Note `NDB': mysql-cluster. storage engine. (See Bug#31321 for more information.)  File: manual.info, Node: mysql-cluster-limitations-error-handling, Next: mysql-cluster-limitations-database-objects, Prev: mysql-cluster-limitations-transactions, Up: mysql-cluster-limitations 17.1.6.4 MySQL Cluster Error Handling ..................................... Starting, stopping, or restarting a node may give rise to temporary errors causing some transactions to fail. These include the following cases: * Temporary errors When first starting a node, it is possible that you may see Error 1204 `Temporary failure, distribution changed' and similar temporary errors. * Errors due to node failure The stopping or failure of any data node can result in a number of different node failure errors. (However, there should be no aborted transactions when performing a planned shutdown of the cluster.) In either of these cases, any errors that are generated must be handled within the application. This should be done by retrying the transaction. See also *Note mysql-cluster-limitations-limits::.  File: manual.info, Node: mysql-cluster-limitations-database-objects, Next: mysql-cluster-limitations-unsupported, Prev: mysql-cluster-limitations-error-handling, Up: mysql-cluster-limitations 17.1.6.5 Limits Associated with Database Objects in MySQL Cluster ................................................................. Some database objects such as tables and indexes have different limitations when using the *Note `NDBCLUSTER': mysql-cluster. storage engine: * Table names containing special characters *Note `NDB': mysql-cluster. tables whose names contain characters other than letters, numbers, dashes, and underscores and which are created on one SQL node were not always discovered correctly by other SQL nodes. (Bug#31470) *Note*: This issue was fixed in MySQL 5.1.23, MySQL Cluster NDB 6.2.7, and MySQL Cluster NDB 6.3.4. * Number of database objects The maximum number of _all_ *Note `NDB': mysql-cluster. database objects in a single MySQL Cluster--including databases, tables, and indexes--is limited to 20320. * Attributes per table Prior to MySQL Cluster NDB 7.0.15 and MySQL Cluster NDB 7.1.4, the maximum number of attributes (that is, columns and indexes) per table is limited to 128. Beginning with MySQL Cluster NDB 7.0.15 and MySQL Cluster NDB 7.1.4, this limit is increased to 512. * Attributes per key The maximum number of attributes per key is 32. * Row size The maximum permitted size of any one row is 8052 bytes. Each *Note `BLOB': blob. or *Note `TEXT': blob. column contributes 256 + 8 = 264 bytes to this total. * Number of rows per partition A single MySQL Cluster partition can hold a maximum of 46137488 rows. Since the number of partitions is the same as the number of data nodes in the cluster (see *Note mysql-cluster-nodes-groups::), you can increase the available space for data storage by using more data nodes. In MySQL Cluster NDB 7.0 and later MySQL Cluster release series, you can increase the number of data nodes in the cluster while the cluster remains in operation. See *Note mysql-cluster-online-add-node::, for more information. It is also possible to increase the number of partitions for *Note `NDB': mysql-cluster. tables by using explicit `KEY' or `LINEAR KEY' partitioning (see *Note partitioning-key::).  File: manual.info, Node: mysql-cluster-limitations-unsupported, Next: mysql-cluster-limitations-performance, Prev: mysql-cluster-limitations-database-objects, Up: mysql-cluster-limitations 17.1.6.6 Unsupported or Missing Features in MySQL Cluster ......................................................... A number of features supported by other storage engines are not supported for *Note `NDB': mysql-cluster. tables. Trying to use any of these features in MySQL Cluster does not cause errors in or of itself; however, errors may occur in applications that expects the features to be supported or enforced: * Foreign key constraints The foreign key construct is ignored, just as it is in `MyISAM' tables. * Index prefixes Prefixes on indexes are not supported for `NDBCLUSTER' tables. If a prefix is used as part of an index specification in a statement such as *Note `CREATE TABLE': create-table, *Note `ALTER TABLE': alter-table, or *Note `CREATE INDEX': create-index, the prefix is ignored. * `OPTIMIZE' operations `OPTIMIZE' operations are not supported. Beginning with MySQL Cluster NDB 6.3.7, this limitation has been lifted. See *Note mysql-cluster-limitations-resolved::, for more information. * `LOAD TABLE ... FROM MASTER' *Note `LOAD TABLE FROM MASTER': load-table-from-master. is not supported. * Savepoints and rollbacks Savepoints and rollbacks to savepoints are ignored as in `MyISAM'. * Durability of commits There are no durable commits on disk. Commits are replicated, but there is no guarantee that logs are flushed to disk on commit. * Replication Statement-based replication is not supported. Use `--binlog-format=ROW' (or `--binlog-format=MIXED') when setting up cluster replication. See *Note mysql-cluster-replication::, for more information. *Note*: See *Note mysql-cluster-limitations-transactions::, for more information relating to limitations on transaction handling in *Note `NDB': mysql-cluster.  File: manual.info, Node: mysql-cluster-limitations-performance, Next: mysql-cluster-limitations-exclusive-to-cluster, Prev: mysql-cluster-limitations-unsupported, Up: mysql-cluster-limitations 17.1.6.7 Limitations Relating to Performance in MySQL Cluster ............................................................. The following performance issues are specific to or especially pronounced in MySQL Cluster: * Range scans There are query performance issues due to sequential access to the *Note `NDB': mysql-cluster. storage engine; it is also relatively more expensive to do many range scans than it is with either `MyISAM' or `InnoDB'. * Reliability of `Records in range' The `Records in range' statistic is available but is not completely tested or officially supported. This may result in nonoptimal query plans in some cases. If necessary, you can employ `USE INDEX' or `FORCE INDEX' to alter the execution plan. See *Note index-hints::, for more information on how to do this. * Unique hash indexes Unique hash indexes created with `USING HASH' cannot be used for accessing a table if `NULL' is given as part of the key.  File: manual.info, Node: mysql-cluster-limitations-exclusive-to-cluster, Next: mysql-cluster-limitations-disk-data, Prev: mysql-cluster-limitations-performance, Up: mysql-cluster-limitations 17.1.6.8 Issues Exclusive to MySQL Cluster .......................................... The following are limitations specific to the *Note `NDBCLUSTER': mysql-cluster. storage engine: * Machine architecture All machines used in the cluster must have the same architecture. That is, all machines hosting nodes must be either big-endian or little-endian, and you cannot use a mixture of both. For example, you cannot have a management node running on a PowerPC which directs a data node that is running on an x86 machine. This restriction does not apply to machines simply running *Note `mysql': mysql. or other clients that may be accessing the cluster's SQL nodes. * Binary logging MySQL Cluster has the following limitations or restrictions with regard to binary logging: * `sql_log_bin' has no effect on data operations; however, it is supported for schema operations. * MySQL Cluster cannot produce a binary log for tables having *Note `BLOB': blob. columns but no primary key. * Only the following schema operations are logged in a cluster binary log which is _not_ on the *Note `mysqld': mysqld. executing the statement: * *Note `CREATE TABLE': create-table. * *Note `ALTER TABLE': alter-table. * *Note `DROP TABLE': drop-table. * *Note `CREATE DATABASE': create-database. / *Note `CREATE SCHEMA': create-database. * *Note `DROP DATABASE': drop-database. / *Note `DROP SCHEMA': drop-database. * *Note `CREATE TABLESPACE': create-tablespace. * *Note `ALTER TABLESPACE': alter-tablespace. * *Note `DROP TABLESPACE': drop-tablespace. * *Note `CREATE LOGFILE GROUP': create-logfile-group. * *Note `ALTER LOGFILE GROUP': alter-logfile-group. * *Note `DROP LOGFILE GROUP': drop-logfile-group. See also *Note mysql-cluster-limitations-multiple-nodes::.  File: manual.info, Node: mysql-cluster-limitations-disk-data, Next: mysql-cluster-limitations-multiple-nodes, Prev: mysql-cluster-limitations-exclusive-to-cluster, Up: mysql-cluster-limitations 17.1.6.9 Limitations Relating to MySQL Cluster Disk Data Storage ................................................................ Disk Data object maxmimums and minimums Disk data objects are subject to the following maximums and minimums: * Maximum number of tablespaces: 2^32 (4294967296) * Maximum number of data files per tablespace: 2^16 (65536) * The theoretical maximum number of extents per tablespace data file is 2^16 (65536); however, for practical purposes, the recommended maximum number of extents per data file is 2^15 (32768). * Maximum data file size: The theoretical limit is 64G; however, in MySQL 5.1 (including MySQL Cluster NDB 6.X and 7.X through 7.1), the practical upper limit is 32G. This is equivalent to 32768 extents of 1M each. The minimum and maximum possible sizes of extents for tablespace data files are 32K and 2G, respectively. See *Note create-tablespace::, for more information. Disk Data tables and diskless mode Use of Disk Data tables is not supported when running the cluster in diskless mode. Beginning with MySQL 5.1.12, it is prohibited altogether. (Bug#20008)  File: manual.info, Node: mysql-cluster-limitations-multiple-nodes, Next: mysql-cluster-limitations-resolved, Prev: mysql-cluster-limitations-disk-data, Up: mysql-cluster-limitations 17.1.6.10 Limitations Relating to Multiple MySQL Cluster Nodes .............................................................. Multiple SQL nodes The following are issues relating to the use of multiple MySQL servers as MySQL Cluster SQL nodes, and are specific to the *Note `NDBCLUSTER': mysql-cluster. storage engine: * No distributed table locks A *Note `LOCK TABLES': lock-tables. works only for the SQL node on which the lock is issued; no other SQL node in the cluster `sees' this lock. This is also true for a lock issued by any statement that locks tables as part of its operations. (See next item for an example.) * `ALTER TABLE' operations *Note `ALTER TABLE': alter-table. is not fully locking when running multiple MySQL servers (SQL nodes). (As discussed in the previous item, MySQL Cluster does not support distributed table locks.) Multiple management nodes When using multiple management servers: * You must give nodes explicit IDs in connectstrings because automatic allocation of node IDs does not work across multiple management servers. * You must take extreme care to have the same configurations for all management servers. No special checks for this are performed by the cluster. Multiple network addresses Multiple network addresses per data node are not supported. Use of these is liable to cause problems: In the event of a data node failure, an SQL node waits for confirmation that the data node went down but never receives it because another route to that data node remains open. This can effectively make the cluster inoperable. *Note*: It is possible to use multiple network hardware _interfaces_ (such as Ethernet cards) for a single data node, but these must be bound to the same address. This also means that it not possible to use more than one `[tcp]' section per connection in the `config.ini' file. See *Note mysql-cluster-tcp-definition::, for more information.  File: manual.info, Node: mysql-cluster-limitations-resolved, Prev: mysql-cluster-limitations-multiple-nodes, Up: mysql-cluster-limitations 17.1.6.11 Previous MySQL Cluster Issues Resolved in MySQL 5.1, MySQL Cluster NDB 6.x, and MySQL Cluster NDB 7.x ............................................................................................................... A number of limitations and related issues existing in earlier versions of MySQL Cluster have been resolved: * Variable-length column support The *Note `NDBCLUSTER': mysql-cluster. storage engine now supports variable-length column types for in-memory tables. Previously, for example, any Cluster table having one or more *Note `VARCHAR': char. fields which contained only relatively small values, much more memory and disk space were required when using the *Note `NDBCLUSTER': mysql-cluster. storage engine than would have been the case for the same table and data using the `MyISAM' engine. In other words, in the case of a *Note `VARCHAR': char. column, such a column required the same amount of storage as a *Note `CHAR': char. column of the same size. In MySQL 5.1, this is no longer the case for in-memory tables, where storage requirements for variable-length column types such as *Note `VARCHAR': char. and `BINARY' are comparable to those for these column types when used in `MyISAM' tables (see *Note storage-requirements::). *Important*: For MySQL Cluster Disk Data tables, the fixed-width limitation continues to apply. See *Note mysql-cluster-disk-data::. * Replication with MySQL Cluster It is now possible to use MySQL replication with Cluster databases. For details, see *Note mysql-cluster-replication::. Circular Replication Circular replication is also supported with MySQL Cluster, beginning with MySQL 5.1.18. See *Note mysql-cluster-replication-multi-master::. * `auto_increment_increment' and `auto_increment_offset' The `auto_increment_increment' and `auto_increment_offset' server system variables are supported for Cluster replication beginning with MySQL 5.1.20, MySQL Cluster NDB 6.2.5, and MySQL Cluster 6.3.2. * Database autodiscovery and online schema changes Autodiscovery of databases is now supported for multiple MySQL servers accessing the same MySQL Cluster. Formerly, autodiscovery in MySQL Cluster 5.1 and MySQL Cluster NDB 6.x releases required that a given *Note `mysqld': mysqld. was already running and connected to the cluster at the time that the database was created on a different *Note `mysqld': mysqld.--in other words, when a *Note `mysqld': mysqld. process connected to the cluster after a database named DB_NAME was created, it was necessary to issue a `CREATE DATABASE DB_NAME' or `CREATE SCHEMA DB_NAME' statement on the `new' MySQL server when it first accesseed that MySQL Cluster. Beginning with MySQL Cluster NDB 6.2.16 and MySQL Cluster NDB 6.3.18, such a `CREATE' statement is no longer required. (Bug#39612) This also means that online schema changes in *Note `NDB': mysql-cluster. tables are now possible. That is, the result of operations such as *Note `ALTER TABLE': alter-table. and *Note `CREATE INDEX': create-index. performed on one SQL node in the cluster are now visible to the cluster's other SQL nodes without any additional action being taken. * Backup and restore between architectures Beginning with MySQL 5.1.10, it is possible to perform a Cluster backup and restore between different architectures. Previously--for example--you could not back up a cluster running on a big-endian platform and then restore from that backup to a cluster running on a little-endian system. (Bug#19255) * Character set directory Beginning with MySQL 5.1.10, it is possible to install MySQL with Cluster support to a nondefault location and change the search path for font description files using either the `--basedir' or `--character-sets-dir' options. (Previously, *Note `ndbd': mysql-cluster-programs-ndbd. in MySQL 5.1 searched only the default path--typically `/usr/local/mysql/share/mysql/charsets'--for character sets.) * Multiple management servers In MySQL 5.1 (including all MySQL Cluster NDB 6.x and later versions), it is no longer necessary, when running multiple management servers, to restart all the cluster's data nodes to enable the management nodes to see one another. Also, when using multiple management servers and starting concurrently several API nodes (possibly including one or more SQL nodes) whose connectstrings listed the management servers in different order, it was possible for 2 API nodes to be assigned the same node ID. This issue is resolved in MySQL Cluster NDB 6.2.17, 6.3.23, and 6.4.3. (Bug#42973) * Multiple data node processes per host Beginning with MySQL Cluster NDB 6.2.0, you can use multiple data node processes on a single host. (In MySQL Cluster NDB 6.1, MySQL 5.1, and earlier release series, we did not support production MySQL Cluster deployments in which more than one *Note `ndbd': mysql-cluster-programs-ndbd. process was run on a single physical machine.) In addition, MySQL Cluster NDB 7.0 introduces support for multi-threaded data nodes (*Note `ndbmtd': mysql-cluster-programs-ndbmtd.). See *Note mysql-cluster-development-5-1-ndb-7-0::, and *Note mysql-cluster-programs-ndbmtd::, for more information. * Identifiers Formerly (in MySQL 5.0 and earlier), database names, table names and attribute names could not be as long for *Note `NDB': mysql-cluster. tables as tables using other storage engines, because attribute names were truncated internally. In MySQL 5.1 and later, names of MySQL Cluster databases, tables, and table columns follow the same rules regarding length as they do for any other storage engine. * Length of `CREATE TABLE' statements *Note `CREATE TABLE': create-table. statements may be no more than 4096 characters in length. _This limitation affects MySQL 5.1.6, 5.1.7, and 5.1.8 only_. (See Bug#17813) * `IGNORE' and `REPLACE' functionality In MySQL 5.1.7 and earlier, *Note `INSERT IGNORE': insert, *Note `UPDATE IGNORE': update, and *Note `REPLACE': replace. were supported only for primary keys, but not for unique keys. It was possible to work around this issue by removing the constraint, then dropping the unique index, performing any inserts, and then adding the unique index again. This limitation was removed for *Note `INSERT IGNORE': insert. and *Note `REPLACE': replace. in MySQL 5.1.8. (See Bug#17431.) * `AUTO_INCREMENT' columns In MySQL 5.1.10 and earlier versions, the maximum number of tables having `AUTO_INCREMENT' columns--including those belonging to hidden primary keys--was 2048. This limitation was lifted in MySQL 5.1.11. * Maximum number of cluster nodes Prior to MySQL Cluster NDB 6.1.1, the total maximum number of nodes in a MySQL Cluster was 63, including all SQL nodes (MySQL Servers), API nodes (applications accessing the cluster other than MySQL servers), data nodes, and management servers. Starting with MySQL Cluster NDB 6.1.1, the total maximum number of nodes in a MySQL Cluster is 255, including all SQL nodes (MySQL Servers), API nodes (applications accessing the cluster other than MySQL servers), data nodes, and management servers. The total number of data nodes and management nodes beginning with this version is 63, of which up to 48 can be data nodes. *Note*: The limitation that a data node cannot have a node ID greater than 49 continues to apply. * Recovery of memory from deleted rows Beginning with MySQL Cluster NDB 6.3.7, memory can be reclaimed from an *Note `NDB': mysql-cluster. table for reuse with any *Note `NDB': mysql-cluster. table by employing *Note `OPTIMIZE TABLE': optimize-table, subject to the following limitations: * Only in-memory tables are supported; the *Note `OPTIMIZE TABLE': optimize-table. statement still has no effect on MySQL Cluster Disk Data tables. * Only variable-length columns (such as those declared as *Note `VARCHAR': char, *Note `TEXT': blob, or *Note `BLOB': blob.) are supported. However, you can force columns defined using fixed-length data types (such as *Note `CHAR': char.) to be dynamic using the `ROW_FORMAT' or `COLUMN_FORMAT' option with a *Note `CREATE TABLE': create-table. or *Note `ALTER TABLE': alter-table. statement. See *Note create-table::, and *Note alter-table::, for information on these options. You can regulate the effects of `OPTIMIZE' on performance by adjusting the value of the global system variable `ndb_optimization_delay', which sets the number of milliseconds to wait between batches of rows being processed by `OPTIMIZE'. The default value is 10 milliseconds. It is possible to set a lower value (to a minimum of `0'), but not recommended. The maximum is 100000 milliseconds (that is, 100 seconds). * Implicit Rollbacks Prior to MySQL Cluster NDB 6.2.17 and MySQL Cluster NDB 6.3.19, MySQL Cluster did not automtically roll back a transaction that was aborted by a duplicate key or similar error, and subsequent statements raised `ERROR 1296 (HY000): Got error 4350 'Transaction already aborted' from NDBCLUSTER'. In such cases, it was necessary to issue an explicit *Note `ROLLBACK': commit. statement first, and then to retry the entire transaction. Beginning with MySQL Cluster NDB 6.2.17 and MySQL Cluster NDB 6.3.19, this limitation has been removed; now, an error which causes a transaction to be aborted generates an implicit rollback of the entire transaction. This is logged with the warning `Storage engine NDB does not support rollback for this statement. Transaction rolled back and must be restarted'. A statement subsequent to this starts a new transaction. (Bug#32656) *Note*: The *Note `NDBCLUSTER': mysql-cluster. storage engine does not support partial transactions or partial rollbacks of transactions in any version of MySQL Cluster. * Number of tables Previously, the maximum number of *Note `NDBCLUSTER': mysql-cluster. tables in a single MySQL Cluster was 1792, but this is no longer the case in MySQL 5.1 and later MySQL Cluster releases. However, the number of tables is still included in the total maximum number of *Note `NDBCLUSTER': mysql-cluster. database objects (20320). (See *Note mysql-cluster-limitations-database-objects::.) * DDL operations Beginning with MySQL Cluster NDB 6.4.0, DDL operations (such as *Note `CREATE TABLE': create-table. or *Note `ALTER TABLE': alter-table.) are protected from data node failures. Previously, if a data node failed while trying to perform one of these, the data dictionary became locked and no further DDL statements could be executed without restarting the cluster (Bug#36718). * Adding and dropping of data nodes In MySQL Cluster NDB 6.3 and previous versions of MySQL Cluster, the online adding or dropping of data nodes was not possible; such operations required a complete shutdown and restart of the entire cluster. In MySQL Cluster NDB 7.0 (beginning with MySQL Cluster NDB 6.4.0) and later MySQL Cluster release series, it is possible to add new data nodes to a running MySQL Cluster by performing a rolling restart, so that the cluster and the data stored in it remain available to applications. When planning to increase the number of data nodes in the cluster online in MySQL Cluster NDB 7.0 or MySQL Cluster NDB 7.1, you should be aware of and take into account the following issues: * New data nodes can be added online to a MySQL Cluster only as part of a new node group. * New data nodes can be added online, but cannot yet be dropped online. Reducing the number of data nodes still requires a system restart of the cluster. * As in previous MySQL Cluster releases, it is not possible to change online either the number of replicas (`NoOfReplicas' configuration parameter) or the number of data nodes per node group. These changes require a system restart. * Redistribution of existing cluster data using the new data nodes is not automatic; however, this can be accomplished using simple SQL statements in the *Note `mysql': mysql. client or other MySQL client application once the nodes have been added. During this procedure, it is not possible to perform DDL operations, although DML operations can continue as normal. The distribution of new cluster data (that is, data stored in the cluster _after_ the new nodes have been added) uses the new nodes without manual intervention. For more information, see *Note mysql-cluster-online-add-node::. * Native support for default column values Starting with MySQL Cluster NDB 7.1.0, default values for table columns are stored by *Note `NDBCLUSTER': mysql-cluster, rather than by the MySQL server as was previously the case. Because less data must be sent from an SQL node to the data nodes, inserts on tables having column value defaults can be performed more efficiently than before. Tables created using previous MySQL Cluster releases can still be used in MySQL Cluster 7.1.0 and later, although they do not support native default values and continue to use defaults supplied by the MySQL server until they are upgraded. This can be done by means of an offline *Note `ALTER TABLE': alter-table. statement. *Important*: You cannot set or change a table column's default value using an online *Note `ALTER TABLE': alter-table. operation * `InnoDB' plugin support Previously, *Note `InnoDB': innodb-storage-engine. support in MySQL Cluster was limited to the version built in to the MySQl Server. Beginning with MySQL Cluster NDB 7.1.9, MySQL Cluster also provides support for the *Note `InnoDB': innodb-storage-engine. Plugin. See *Note mysql-cluster-installation::, for information about enabling *Note `InnoDB': innodb-storage-engine. storage engine and plugin support with MySQL Cluster. * Distribution of MySQL users and privileges Previously, MySQL users and privileges created on one SQL node were unique to that SQL node, due to the fact that the MySQL grant tables were restricted to using the *Note `MyISAM': myisam-storage-engine. storage engine. Beginning with MySQL Cluster NDB 7.2.0, it is possible, following installation of the MySQL Cluster software and setup of the desired users and privileges on one SQL node, to convert the grant tables to use *Note `NDB': mysql-cluster. and thus to distribute the users and privileges across all SQL nodes connected to the cluster. You can do this by loading and making use of a set of stored procedures defined in an SQL script supplied with the MySQL Cluster distribution. For more information, see *Note mysql-cluster-privilege-distribution::.  File: manual.info, Node: mysql-cluster-installation, Next: mysql-cluster-configuration, Prev: mysql-cluster-overview, Up: mysql-cluster 17.2 MySQL Cluster Installation =============================== * Menu: * mysql-cluster-install-linux:: Installing MySQL Cluster on Linux * mysql-cluster-install-windows:: Installing MySQL Cluster on Windows * mysql-cluster-install-configuration:: Initial Configuration of MySQL Cluster * mysql-cluster-install-first-start:: Initial Startup of MySQL Cluster * mysql-cluster-install-example-data:: MySQL Cluster Example with Tables and Data * mysql-cluster-install-shutdown-restart:: Safe Shutdown and Restart of MySQL Cluster * mysql-cluster-upgrade-downgrade:: Upgrading and Downgrading MySQL Cluster This section describes the basics for planning, installing, configuring, and running a MySQL Cluster. Whereas the examples in *Note mysql-cluster-configuration:: provide more in-depth information on a variety of clustering options and configuration, the result of following the guidelines and procedures outlined here should be a usable MySQL Cluster which meets the _minimum_ requirements for availability and safeguarding of data. This section covers hardware and software requirements; networking issues; installation of MySQL Cluster; configuration issues; starting, stopping, and restarting the cluster; loading of a sample database; and performing queries. Assumptions The following sections make a number of assumptions regarding the cluster's physical and network configuration. These assumptions are discussed in the next few paragraphs. Cluster nodes and host computers The cluster consists of four nodes, each on a separate host computer, and each with a fixed network address on a typical Ethernet network as shown here: Node IP Address Management node (`mgmd') 192.168.0.10 SQL node (*Note `mysqld': mysqld.) 192.168.0.20 Data node "A" (*Note `ndbd': 192.168.0.30 mysql-cluster-programs-ndbd.) Data node "B" (*Note `ndbd': 192.168.0.40 mysql-cluster-programs-ndbd.) This may be made clearer by the following diagram: MySQL Cluster Multi-Computer Setup Network addressing In the interest of simplicity (and reliability), this `How-To' uses only numeric IP addresses. However, if DNS resolution is available on your network, it is possible to use host names in lieu of IP addresses in configuring Cluster. Alternatively, you can use the `hosts' file (typically `/etc/hosts' for Linux and other Unix-like operating systems, `C:\WINDOWS\system32\drivers\etc\hosts' on Windows, or your operating system's equivalent) for providing a means to do host lookup if such is available. Potential hosts file issues A common problem when trying to use host names for Cluster nodes arises because of the way in which some operating systems (including some Linux distributions) set up the system's own host name in the `/etc/hosts' during installation. Consider two machines with the host names `ndb1' and `ndb2', both in the `cluster' network domain. Red Hat Linux (including some derivatives such as CentOS and Fedora) places the following entries in these machines' `/etc/hosts' files: # ndb1 `/etc/hosts': 127.0.0.1 ndb1.cluster ndb1 localhost.localdomain localhost # ndb2 `/etc/hosts': 127.0.0.1 ndb2.cluster ndb2 localhost.localdomain localhost SUSE Linux (including OpenSUSE) places these entries in the machines' `/etc/hosts' files: # ndb1 `/etc/hosts': 127.0.0.1 localhost 127.0.0.2 ndb1.cluster ndb1 # ndb2 `/etc/hosts': 127.0.0.1 localhost 127.0.0.2 ndb2.cluster ndb2 In both instances, `ndb1' routes `ndb1.cluster' to a loopback IP address, but gets a public IP address from DNS for `ndb2.cluster', while `ndb2' routes `ndb2.cluster' to a loopback address and obtains a public address for `ndb1.cluster'. The result is that each data node connects to the management server, but cannot tell when any other data nodes have connected, and so the data nodes appear to hang while starting. *Caution*: You cannot mix `localhost' and other host names or IP addresses in `config.ini'. For these reasons, the solution in such cases (other than to use IP addresses for _all_ `config.ini' `HostName' entries) is to remove the fully qualified host names from `/etc/hosts' and use these in `config.ini' for all cluster hosts. Host computer type Each host computer in our installation scenario is an Intel-based desktop PC running a supported operating system installed to disk in a standard configuration, and running no unnecessary services. The core operating system with standard TCP/IP networking capabilities should be sufficient. Also for the sake of simplicity, we also assume that the file systems on all hosts are set up identically. In the event that they are not, you should adapt these instructions accordingly. Network hardware Standard 100 Mbps or 1 gigabit Ethernet cards are installed on each machine, along with the proper drivers for the cards, and that all four hosts are connected through a standard-issue Ethernet networking appliance such as a switch. (All machines should use network cards with the same throughout. That is, all four machines in the cluster should have 100 Mbps cards _or_ all four machines should have 1 Gbps cards.) MySQL Cluster works in a 100 Mbps network; however, gigabit Ethernet provides better performance. *Important*: MySQL Cluster is _not_ intended for use in a network for which throughput is less than 100 Mbps or which experiences a high degree of latency. For this reason (among others), attempting to run a MySQL Cluster over a wide area network such as the Internet is not likely to be successful, and is not supported in production. Sample data We use the `world' database which is available for download from the MySQL Web site (see `http://dev.mysql.com/doc/index-other.html'). We assume that each machine has sufficient memory for running the operating system, required MySQL Cluster processes, and (on the data nodes) storing the database. For general information about installing MySQL, see *Note installing::. For information about installation of MySQL Cluster on Linux and other Unix-like operating systems, see *Note mysql-cluster-install-linux::. For information about installation of MySQL Cluster on Windows operating systems, see *Note mysql-cluster-install-windows::. For general information about MySQL Cluster hardware, software, and networking requirements, see *Note mysql-cluster-overview-requirements::.  File: manual.info, Node: mysql-cluster-install-linux, Next: mysql-cluster-install-windows, Prev: mysql-cluster-installation, Up: mysql-cluster-installation 17.2.1 Installing MySQL Cluster on Linux ---------------------------------------- * Menu: * mysql-cluster-install-linux-binary:: Installing a MySQL Cluster Binary Release on Linux * mysql-cluster-install-linux-rpm:: Installing MySQL Cluster from RPM * mysql-cluster-install-linux-source:: Building MySQL Cluster from Source on Linux This section covers installation of MySQL Cluster on Linux and other Unix-like operating systems. While the next few sections refer to a Linux operating system, the instructions and procedures given there should be easily adaptable to other supported Unix-like platforms. Beginning with MySQL Cluster NDB 7.1.3, MySQL Cluster is also supported for production use on Windows operating systems; for installation and setup instructions specific to Windows, see *Note mysql-cluster-install-windows::. Each MySQL Cluster host computer must have the correct executable programs installed. A host running an SQL node must have installed on it a MySQL Server binary (*Note `mysqld': mysqld.). Management nodes require the management server daemon (*Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd.); data nodes require the data node daemon (*Note `ndbd': mysql-cluster-programs-ndbd.; in MySQL Cluster NDB 7.0 and later, you can use *Note `ndbmtd': mysql-cluster-programs-ndbmtd. instead. It is not necessary to install the MySQL Server binary on management node hosts and data node hosts. It is recommended that you also install the management client (*Note `ndb_mgm': mysql-cluster-programs-ndb-mgm.) on the management server host. Installation of MySQL Cluster on Linux can be done using precompiled binaries from Oracle (downloaded as a .tar.gz archive), with RPM packages (also available from Oracle), or from source code. All three of these installation methods are described in the section that follow. Regardless of the method used, it is still necessary following installation of the MySQL Cluster binaries to create configuration files for all cluster nodes, before you can start the cluster. See *Note mysql-cluster-install-configuration::.  File: manual.info, Node: mysql-cluster-install-linux-binary, Next: mysql-cluster-install-linux-rpm, Prev: mysql-cluster-install-linux, Up: mysql-cluster-install-linux 17.2.1.1 Installing a MySQL Cluster Binary Release on Linux ........................................................... This section covers the steps necessary to install the correct executables for each type of Cluster node from precompiled binaries supplied by Oracle. For setting up a cluster using precompiled binaries, the first step in the installation process for each cluster host is to download the latest MySQL Cluster NDB 6.3, MySQL Cluster NDB 7.0, or MySQL Cluster NDB 7.1 binary archive (`mysql-cluster-gpl-6.3.45-linux-i686-glibc23.tar.gz', `mysql-cluster-gpl-7.0.27-linux-i686-glibc23.tar.gz', or `mysql-cluster-gpl-7.1.16-linux-i686-glibc23.tar.gz', respectively) from the MySQL Cluster downloads area (http://dev.mysql.com/downloads/cluster/). We assume that you have placed this file in each machine's `/var/tmp' directory. (If you do require a custom binary, see *Note installing-development-tree::.) *Note*: After completing the installation, do not yet start any of the binaries. We show you how to do so following the configuration of the nodes (see *Note mysql-cluster-install-configuration::). Data nodes and SQL nodes On each of the machines designated to host data nodes or SQL nodes, perform the following steps as the system `root' user: 1. Check your `/etc/passwd' and `/etc/group' files (or use whatever tools are provided by your operating system for managing users and groups) to see whether there is already a `mysql' group and `mysql' user on the system. Some OS distributions create these as part of the operating system installation process. If they are not already present, create a new `mysql' user group, and then add a `mysql' user to this group: shell> groupadd mysql shell> useradd -g mysql mysql The syntax for `useradd' and `groupadd' may differ slightly on different versions of Unix, or they may have different names such as `adduser' and `addgroup'. 2. Change location to the directory containing the downloaded file, unpack the archive, and create a symbolic link named `mysql' to the `mysql' directory. Note that the actual file and directory names vary according to the MySQL Cluster version number. shell> cd /var/tmp shell> tar -C /usr/local -xzvf mysql-cluster-gpl-7.1.16-linux-i686-glibc23.tar.gz shell> ln -s /usr/local/mysql-cluster-gpl-7.1.16-linux-i686-glibc23 /usr/local/mysql 3. Change location to the `mysql' directory and run the supplied script for creating the system databases: shell> cd mysql shell> scripts/mysql_install_db --user=mysql 4. Set the necessary permissions for the MySQL server and data directories: shell> chown -R root . shell> chown -R mysql data shell> chgrp -R mysql . Note that the data directory on each machine hosting a data node is `/usr/local/mysql/data'. This piece of information is essential when configuring the management node. (See *Note mysql-cluster-install-configuration::.) 5. Copy the MySQL startup script to the appropriate directory, make it executable, and set it to start when the operating system is booted up: shell> cp support-files/mysql.server /etc/rc.d/init.d/ shell> chmod +x /etc/rc.d/init.d/mysql.server shell> chkconfig --add mysql.server (The startup scripts directory may vary depending on your operating system and version--for example, in some Linux distributions, it is `/etc/init.d'.) Here we use Red Hat's `chkconfig' for creating links to the startup scripts; use whatever means is appropriate for this purpose on your operating system and distribution, such as `update-rc.d' on Debian. Remember that the preceding steps must be repeated on each machine where an SQL node is to reside. Management nodes Installation of the management node does not require the *Note `mysqld': mysqld. binary. Only the MySQL Cluster management server (*Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd.) is required; you most likely want to install the management client (*Note `ndb_mgm': mysql-cluster-programs-ndb-mgm.) as well. Both of these binaries also be found in the `.tar.gz' archive. Again, we assume that you have placed this archive in `/var/tmp'. As system `root' (that is, after using `sudo', `su root', or your system's equivalent for temporarily assuming the system administrator account's privileges), perform the following steps to install *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. and *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. on the Cluster management node host: 1. Change location to the `/var/tmp' directory, and extract the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. and *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. from the archive into a suitable directory such as `/usr/local/bin': shell> cd /var/tmp shell> tar -zxvf mysql-5.1.56-ndb-7.1.16-linux-i686-glibc23.tar.gz shell> cd mysql-5.1.56-ndb-7.1.16-linux-i686-glibc23 shell> cp bin/ndb_mgm* /usr/local/bin (You can safely delete the directory created by unpacking the downloaded archive, and the files it contains, from `/var/tmp' once *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. and *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. have been copied to the executables directory.) 2. Change location to the directory into which you copied the files, and then make both of them executable: shell> cd /usr/local/bin shell> chmod +x ndb_mgm* In *Note mysql-cluster-install-configuration::, we create configuration files for all of the nodes in our example MySQL Cluster.  File: manual.info, Node: mysql-cluster-install-linux-rpm, Next: mysql-cluster-install-linux-source, Prev: mysql-cluster-install-linux-binary, Up: mysql-cluster-install-linux 17.2.1.2 Installing MySQL Cluster from RPM .......................................... This section covers the steps necessary to install the correct executables for each type of MySQL Cluster node using RPM packages supplied by Oracle. RPMs are available for both 32-bit and 64-bit Linux platforms. For a MySQL Cluster, three RPMs are required: * The *Server* RPM (for example, `MySQL-Cluster-gpl-server-6.3.45-0.sles10.i586.rpm', `MySQL-Cluster-gpl-server-7.0.27-0.sles10.i586.rpm', or `MySQL-Cluster-gpl-server-7.1.16-0.sles10.i586.rpm'), which supplies the core files needed to run a MySQL Server with *Note `NDBCLUSTER': mysql-cluster. storage engine support (that is, as a MySQL Cluster SQL node). If you do not have your own client application capable of administering a MySQL server, you should also obtain and install the *Client* RPM (for example, `MySQL-Cluster-gpl-client-6.3.45-0.sles10.i586.rpm', `MySQL-Cluster-gpl-client-7.0.27-0.sles10.i586.rpm', or `MySQL-Cluster-gpl-client-7.1.16-0.sles10.i586.rpm'). * The *Cluster storage engine* RPM (for example, `MySQL-Cluster-gpl-storage-6.3.45-0.sles10.i586.rpm', `MySQL-Cluster-gpl-storage-7.0.27-0.sles10.i586.rpm', or `MySQL-Cluster-gpl-storage-7.1.16-0.sles10.i586.rpm'), which supplies the MySQL Cluster data node binary (*Note `ndbd': mysql-cluster-programs-ndbd.). * The *Cluster storage engine management RPM* (for example, `MySQL-Cluster-gpl-management-6.3.45-0.sles10.i586.rpm', `MySQL-Cluster-gpl-management-7.0.27-0.sles10.i586.rpm', or `MySQL-Cluster-gpl-management-7.1.16-0.sles10.i586.rpm') which provides the MySQL Cluster management server binary (*Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd.). In addition, you should also obtain the *NDB Cluster - Storage engine basic tools* RPM (for example, `MySQL-Cluster-gpl-tools-6.3.45-0.sles10.i586.rpm', `MySQL-Cluster-gpl-tools-7.0.27-0.sles10.i586.rpm', or `MySQL-Cluster-gpl-tools-7.1.16-0.sles10.i586.rpm'), which supplies several useful applications for working with a MySQL Cluster. The most important of these is the MySQL Cluster management client (*Note `ndb_mgm': mysql-cluster-programs-ndb-mgm.). The *NDB Cluster - Storage engine extra tools* RPM (for example, `MySQL-Cluster-gpl-extra-6.3.45-0.sles10.i586.rpm', `MySQL-Cluster-gpl-extra-7.0.27-0.sles10.i586.rpm', or `MySQL-Cluster-gpl-extra-7.1.16-0.sles10.i586.rpm') contains some additional testing and monitoring programs, but is not required to install a MySQL Cluster. (For more information about these additional programs, see *Note mysql-cluster-programs::.) The MySQL Cluster version number in the RPM file names (shown here as `6.3.45', `7.0.27', or `7.1.16') can vary according to the version which you are actually using. _It is very important that all of the Cluster RPMs to be installed have the same version number_. The `glibc' version number (if present), and architecture designation (shown here as `i586') should be appropriate to the machine on which the RPM is to be installed. Data nodes On a computer that is to host a cluster data node it is necessary to install only the *NDB Cluster - Storage engine* RPM. To do so, copy this RPM to the data node host, and run the following command as the system root user, replacing the name shown for the RPM as necessary to match that of the RPM downloaded from the MySQL web site: shell> rpm -Uhv MySQL-Cluster-gpl-storage-7.1.16-0.sles10.i586.rpm The previous command installs the MySQL Cluster data node binary (*Note `ndbd': mysql-cluster-programs-ndbd.) in the `/usr/sbin' directory. SQL nodes On each machine to be used for hosting a cluster SQL node, install the *Server* RPM by executing the following command as the system root user, replacing the name shown for the RPM as necessary to match the name of the RPM downloaded from the MySQL web site: shell> rpm -Uhv MySQL-Cluster-gpl-server-7.1.16-0.sles10.i586.rpm This installs the MySQL server binary (*Note `mysqld': mysqld.) in the `/usr/sbin' directory, as well as all needed MySQL Server support files. It also installs the *Note `mysql.server': mysql-server. and *Note `mysqld_safe': mysqld-safe. startup scripts in `/usr/share/mysql' and `/usr/bin', respectively. The RPM installer should take care of general configuration issues (such as creating the `mysql' user and group, if needed) automatically. *Note*: To administer the SQL node (MySQL server), you should also install the *Client* RPM, as shown here: shell> rpm -Uhv MySQL-Cluster-gpl-client-7.1.16-0.sles10.i586.rpm This installs the *Note `mysql': mysql. client program. Management nodes To install the MySQL Cluster management server, it is necessary only to use the *NDB Cluster - Storage engine management* RPM. Copy this RPM to the computer intended to host the management node, and then install it by running the following command as the system root user (replace the name shown for the RPM as necessary to match that of the *Storage engine management* RPM downloaded from the MySQL web site): shell> rpm -Uhv MySQL-Cluster-gpl-management-7.1.16-0.sles10.i586.rpm This installs the management server binary (*Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd.) to the `/usr/sbin' directory. You should also install the *Note `NDB': mysql-cluster. management client, which is supplied by the *Storage engine basic tools* RPM. Copy this RPM to the same computer as the management node, and then install it by running the following command as the system root user (again, replace the name shown for the RPM as necessary to match that of the *Storage engine basic tools* RPM downloaded from the MySQL web site): shell> rpm -Uhv MySQL-Cluster-gpl-tools-7.1.16-0.sles10.i586.rpm The *Storage engine basic tools* RPM installs the MySQL Cluster management client (*Note `ndb_mgm': mysql-cluster-programs-ndb-mgm.) to the `/usr/bin' directory. *Note*: You can also install the *Cluster storage engine extra tools* RPM, if you wish, as shown here: shell> rpm -Uhv MySQL-Cluster-gpl-extra-7.1.16-0.sles10.i586.rpm You may find the extra tools useful; however the *Cluster storage engine extra tools* RPM is _not_ required to install a working MySQL Cluster. See *Note linux-installation-rpm::, for general information about installing MySQL using RPMs supplied by Oracle. After installing from RPM, you still need to configure the cluster as discussed in *Note mysql-cluster-install-configuration::.  File: manual.info, Node: mysql-cluster-install-linux-source, Prev: mysql-cluster-install-linux-rpm, Up: mysql-cluster-install-linux 17.2.1.3 Building MySQL Cluster from Source on Linux .................................................... This section provides information about compiling MySQL Cluster on Linux and other Unix-like platforms. Building MySQL Cluster from source is similar to building the standard MySQL Server, although it differs in a few key respects discussed here. For general information about building MySQL from source, see *Note source-installation::. Beginning with MySQL Cluster NDB 7.1.3, MySQL Cluster is also supported on Windows platforms, and can be built on Windows from source. For information about compiling MySQL Cluster on Windows platforms, see *Note mysql-cluster-install-windows-source::. Building MySQL Cluster requires using the MySQL Cluster sources. These are available from the MySQL Cluster downloads page at http://dev.mysql.com/downloads/cluster/. The archived source file should have a name similar to `mysql-cluster-gpl-6.3.45.tar.gz', `mysql-cluster-gpl-7.0.27.tar.gz', or `mysql-cluster-gpl-7.1.16.tar.gz'. You can also obtain MySQL development sources from launchpad.net. Attempting to build MySQL Cluster from standard MySQL 5.1 sources is not supported. In addition to any other `configure' options you wish to use, be sure to include `--with-plugins=ndbcluster', `--with-plugins=max', or , or `--with-plugins=max-no-innodb'. Either of these options causes the binaries for the management nodes, data nodes, and other MySQL Cluster programs to be built; it also causes *Note `mysqld': mysqld. to be compiled with *Note `NDB': mysql-cluster. storage engine support. After you have run `make && make install' (or your system's equivalent), the result is similar to what is obtained by unpacking a precompiled binary to the same location. However, the layout can differ. These differences are covered in the next few paragraphs. Prior to MySQL Cluster NDB 7.1.9, MySQL Cluster was not compatible with the *Note `InnoDB': innodb-storage-engine. Plugin; in earlier MySQL Cluster releases, only the version of *Note `InnoDB': innodb-storage-engine. supplied with the MySQL Server could be used. Beginning with MySQL Cluster NDB 7.1.9, you can build MySQL Cluster with *Note `InnoDB': innodb-storage-engine. storage engine or plugin support using the appropriate `--with-plugins' option for `configure'. Management nodes When building from source and running the default `make install', the management server binary (*Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd.) is placed in `/usr/local/mysql/libexec', while the management client binary (*Note `ndb_mgm': mysql-cluster-programs-ndb-mgm.) can be found in `/usr/local/mysql/bin'. Only *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. is required to be present on a management node host; however, it is also a good idea to have *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. present on the same host machine. Neither of these executables requires a specific location on the host machine's file system. Data nodes The only executable required on a data node host is *Note `ndbd': mysql-cluster-programs-ndbd. (*Note `mysqld': mysqld, for example, does not have to be present on the host machine). By default when doing a source build, this file is placed in the directory `/usr/local/mysql/libexec'. For installing on multiple data node hosts, only *Note `ndbd': mysql-cluster-programs-ndbd. need be copied to the other host machine or machines. (This assumes that all data node hosts use the same architecture and operating system; otherwise you may need to compile separately for each different platform.) *Note `ndbd': mysql-cluster-programs-ndbd. need not be in any particular location on the host's file system, as long as the location is known. When compiling MySQL Cluster NDB 7.0 or later from source, no special options are required for building multi-threaded data node binaries. On Unix platforms, configuring the build with any of the options `--with-plugins=ndbcluster', `--with-plugins=max', or `--with-plugins=max-no-innodb' causes *Note `ndbmtd': mysql-cluster-programs-ndbmtd. to be built automatically; `make install' places the *Note `ndbmtd': mysql-cluster-programs-ndbmtd. binary in the `libexec' directory along with *Note `mysqld': mysqld, *Note `ndbd': mysql-cluster-programs-ndbd, and *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. SQL nodes If you compile MySQL with clustering support, and perform the default installation (using `make install' as the system `root' user), *Note `mysqld': mysqld. is placed in `/usr/local/mysql/bin'. Follow the steps given in *Note source-installation:: to make *Note `mysqld': mysqld. ready for use. If you want to run multiple SQL nodes, you can use a copy of the same *Note `mysqld': mysqld. executable and its associated support files on several machines. The easiest way to do this is to copy the entire `/usr/local/mysql' directory and all directories and files contained within it to the other SQL node host or hosts, then repeat the steps from *Note source-installation:: on each machine. If you configure the build with a nondefault `--prefix', you need to adjust the directory accordingly. In *Note mysql-cluster-install-configuration::, we create configuration files for all of the nodes in our example MySQL Cluster.  File: manual.info, Node: mysql-cluster-install-windows, Next: mysql-cluster-install-configuration, Prev: mysql-cluster-install-linux, Up: mysql-cluster-installation 17.2.2 Installing MySQL Cluster on Windows ------------------------------------------ * Menu: * mysql-cluster-install-windows-binary:: Installing MySQL Cluster on Windows from a Binary Release * mysql-cluster-install-windows-source:: Compiling and Installing MySQL Cluster from Source on Windows * mysql-cluster-install-windows-initial-start:: Initial Startup of MySQL Cluster on Windows * mysql-cluster-install-windows-service:: Installing MySQL Cluster Processes as Windows Services Experimental support for MySQL Cluster on Microsoft Windows operating systems was introduced in MySQL Cluster NDB 7.0. Beginning with MySQL Cluster NDB 7.1.3, production support is provided for MySQL Cluster on Windows, and MySQL Cluster binaries for Windows can be obtained from `http://dev.mysql.com/downloads/cluster/'. For information about installing MySQL Cluster on Windows from a binary release provided by Oracle, see *Note mysql-cluster-install-windows-binary::. It is also possible to compile and install MySQL Cluster from source on Windows using Microsoft Visual Studio. For more information, see *Note mysql-cluster-install-windows-source::.  File: manual.info, Node: mysql-cluster-install-windows-binary, Next: mysql-cluster-install-windows-source, Prev: mysql-cluster-install-windows, Up: mysql-cluster-install-windows 17.2.2.1 Installing MySQL Cluster on Windows from a Binary Release .................................................................. This section describes a basic installation of MySQL Cluster on Windows using a binary `no-install' MySQL Cluster release provided by Oracle, using the same 4-node setup outlined in the beginning of this section (see *Note mysql-cluster-installation::), as shown in the following table: Node IP Address Management (MGMD) node 192.168.0.10 MySQL server (SQL) node 192.168.0.20 Data (NDBD) node "A" 192.168.0.30 Data (NDBD) node "B" 192.168.0.40 As on other platforms, the MySQL Cluster host computer running an SQL node must have installed on it a MySQL Server binary (*Note `mysqld.exe': mysqld.). You should also have the MySQL client (*Note `mysql.exe': mysql.) on on this host. For management nodes and data nodes, it is not necessary to install the MySQL Server binary; however, each management node requires the management server daemon (*Note `ndb_mgmd.exe': mysql-cluster-programs-ndb-mgmd.); each data node requires the data node daemon (*Note `ndbd.exe': mysql-cluster-programs-ndbd. or *Note `ndbmtd.exe': mysql-cluster-programs-ndbmtd.). For this example, we refer to *Note `ndbd.exe': mysql-cluster-programs-ndbd. as the data node executable, but you can install *Note `ndbmtd.exe': mysql-cluster-programs-ndbmtd, the multi-threaded version of this program, instead, in exactly the same way. You should also install the management client (*Note `ndb_mgm.exe': mysql-cluster-programs-ndb-mgm.) on the management server host. This section covers the steps necessary to install the correct Windows binaries for each type of MySQL Cluster node. *Note `ndbmtd.exe': mysql-cluster-programs-ndbmtd. was not included in MySQL Cluster NDB 7.1.3 binary releases for Windows, due to a problem with *Note `make_win_bin_dist': make-win-bin-dist. This issue was corrected in MySQL Cluster NDB 7.1.5. *Note*: As with other Windows programs, MySQL Cluster executables are named with the `.exe' file extension. However, it is not necessary to include the `.exe' extension when invoking these programs from the command line. Therefore, we often simply refer to these programs in this documentation as *Note `mysqld': mysqld, *Note `mysql': mysql, *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd, and so on. You should understand that, whether we refer (for example) to *Note `mysqld': mysqld. or *Note `mysqld.exe': mysqld, either name means the same thing (the MySQL Server program). For setting up a MySQL Cluster using Oracles's `no-install' binaries, the first step in the installation process is to download the latest MySQL Cluster Windows binary archive from `http://dev.mysql.com/downloads/cluster/'. This archive has a filename of the form `mysql-cluster-gpl-noinstall-VER-winARCH.zip', where VER is the `NDB' storage engine version (such as `7.1.3'), and ARCH is the architecture (`32' for 32-bit binaries, and `64' for 64-bit binaries). For example, the MySQL Cluster NDB 7.1.3 `no-install' archive for 32-bit Windows systems is named `mysql-cluster-gpl-noinstall-7.1.3-win32.zip'. You can run 32-bit MySQL Cluster binaries on both 32-bit and 64-bit versions of Windows; however, 64-bit MySQL Cluster binaries can be used only on 64-bit versions of Windows. If you are using a 32-bit version of Windows on a computer that has a 64-bit CPU, then you must use the 32-bit MySQL Cluster binaries. To minimize the number of files that need to be downloaded from the Internet or copied between machines, we start with the computer where you intend to run the SQL node. SQL node We assume that you have placed a copy of the `no-install' archive in the directory `C:\Documents and Settings\USERNAME\My Documents\Downloads' on the computer having the IP address 192.168.0.20, where USERNAME is the name of the current user. (You can obtain this name using `ECHO %USERNAME%' on the command line.) To install and run MySQL Cluster executables as Windows services, this user should be a member of the `Administrators' group. Extract all the files from the archive. The Extraction Wizard integrated with Windows Explorer is adequate for this task. (If you use a different archive program, be sure that it extracts all files and directories from the archive, and that it preserves the archive's directory structure.) When you are asked for a destination directory, enter `C:\', which causes the Extraction Wizard to extract the archive to the directory `C:\mysql-cluster-gpl-noinstall-VER-winARCH'. Rename this directory to `C:\mysql'. It is possible to install the MySQL Cluster binaries to directories other than `C:\mysql\bin'; however, if you do so, you must modify the paths shown in this procedure accordingly. In particular, if the MySQL Server (SQL node) binary is installed to a location other than `C:\mysql' or `C:\Program Files\MySQL\MySQL Server 5.1', or if the SQL node's data directory is in a location other than `C:\mysql\data' or `C:\Program Files\MySQL\MySQL Server 5.1\data', extra configuration options must be used on the command line or added to the `my.ini' or `my.cnf' file when starting the SQL node. For more information about configuring a MySQL Server to run in a nonstandard location, see *Note windows-install-archive::. For a MySQL Server with MySQL Cluster support to run as part of a MySQL Cluster, it must be started with the options `--ndbcluster' and `--ndb-connectstring'. While you can specify these options on the command line, it is usually more convenient to place them in an option file. To do this, create a new text file in Notepad or another text editor. Enter the following configuration information into this file: [mysqld] # Options for mysqld process: ndbcluster # run NDB storage engine ndb-connectstring=192.168.0.10 # location of management server You can add other options used by this MySQL Server if desired (see *Note windows-create-option-file::), but the file must contain the options shown, at a minimum. Save this file as `C:\mysql\my.ini'. This completes the installation and setup for the SQL node. Data nodes A MySQL Cluster data node on a Windows host requires only a single executable, one of either *Note `ndbd.exe': mysql-cluster-programs-ndbd. or *Note `ndbmtd.exe': mysql-cluster-programs-ndbmtd. For this example, we assume that you are using *Note `ndbd.exe': mysql-cluster-programs-ndbd, but the same instructions apply when using *Note `ndbmtd.exe': mysql-cluster-programs-ndbmtd. On each computer where you wish to run a data node (the computers having the IP addresses 192.168.0.30 and 192.168.0.40), create the directories `C:\mysql', `C:\mysql\bin', and `C:\mysql\cluster-data'; then, on the computer where you downloaded and extracted the `no-install' archive, locate `ndbd.exe' in the `C:\mysql\bin' directory. Copy this file to the `C:\mysql\bin' directory on each of the two data node hosts. To function as part of a MySQL Cluster, each data node must be given the address or hostname of the management server. You can supply this information on the command line using the `--ndb-connectstring' or `-c' option when starting each data node process. However, it is usually preferable to put this information in an option file. To do this, create a new text file in Notepad or another text editor and enter the following text: [mysql_cluster] # Options for data node process: ndb-connectstring=192.168.0.10 # location of management server Save this file as `C:\mysql\my.ini' on the data node host. Create another text file containing the same information and save it on as `C:mysql\my.ini' on the other data node host, or copy the my.ini file from the first data node host to the second one, making sure to place the copy in the second data node's `C:\mysql' directory. Both data node hosts are now ready to be used in the MySQL Cluster, which leaves only the management node to be installed and configured. Management node The only executable program required on a computer used for hosting a MySQL Cluster management node is the management server program *Note `ndb_mgmd.exe': mysql-cluster-programs-ndb-mgmd. However, in order to administer the MySQL Cluster once it has been started, you should also install the MySQL Cluster management client program *Note `ndb_mgm.exe': mysql-cluster-programs-ndb-mgm. on the same machine as the management server. Locate these two programs on the machine where you downloaded and extracted the `no-install' archive; this should be the directory `C:\mysql\bin' on the SQL node host. Create the directory `C:\mysql\bin' on the computer having the IP address 192.168.0.10, then copy both programs to this directory. You should now create two configuration files for use by `ndb_mgmd.exe': 1. A local configuration file to supply configuration data spcific to the management node itself. Typically, this file needs only to supply the location of the MySQL Cluster global configuration file (see item 2). To create this file, start a new text file in Notepad or another text editor, and enter the following information: [mysql_cluster] # Options for management node process config-file=C:/mysql/bin/config.ini Save this file as the plaintext file `C:\mysql\bin\my.ini'. 2. A global configuration file from which the management node can obtain configuration information governing the MySQL Cluster as a whole. At a minimum, this file must contain a section for each node in the MySQL Cluster, and the IP addresses or hostnames for the management node and all data nodes (`HostName' configuration parameter). It is also advisable to include the following additional information: * The IP address or hostname of any SQL nodes * The data memory and index memory allocated to each data node (`DataMemory' and `IndexMemory' configuration parameters) * The number of replicas, using the `NoOfReplicas' configuration parameter (see *Note mysql-cluster-nodes-groups::) * The directory where each data node stores it data and log file, and the directory where the management node keeps its log files (in both cases, the `DataDir' configuration parameter) Create a new text file using a text editor such as Notepad, and input the following information: [ndbd default] # Options affecting ndbd processes on all data nodes: NoOfReplicas=2 # Number of replicas DataDir=C:/mysql/bin/cluster-data # Directory for each data node's data files # Forward slashes used in directory path, # rather than backslashes. This is correct; # see *Important* note in text DataMemory=80M # Memory allocated to data storage IndexMemory=18M # Memory allocated to index storage # For DataMemory and IndexMemory, we have used the # default values. Since the "world" database takes up # only about 500KB, this should be more than enough for # this example Cluster setup. [ndb_mgmd] # Management process options: HostName=192.168.0.10 # Hostname or IP address of management node DataDir=C:/mysql/bin/cluster-logs # Directory for management node log files [ndbd] # Options for data node "A": # (one [ndbd] section per data node) HostName=192.168.0.30 # Hostname or IP address [ndbd] # Options for data node "B": HostName=192.168.0.40 # Hostname or IP address [mysqld] # SQL node options: HostName=192.168.0.20 # Hostname or IP address Save this file as the plaintext file `C:\mysql\bin\config.ini'. *Important*: A single backslash character (`\') cannot be used when specifying directory paths in program options or configuration files used by MySQL Cluster on Windows. Instead, you must either escape each backslash character with a second backslash (`\\'), or replace the backslash with a forward slash character (`/'). For example, the following line from the `[ndb_mgmd]' section of a MySQL Cluster `config.ini' file does not work: DataDir=C:\mysql\bin\cluster-logs Instead, you may use either of the following: DataDir=C:\\mysql\\bin\\cluster-logs # Escaped backslashes DataDir=C:/mysql/bin/cluster-logs # Forward slashes For reasons of brevity and legibility, we recommend that you use forward slashes in directory paths used in MySQL Cluster program options and configuration files on Windows.  File: manual.info, Node: mysql-cluster-install-windows-source, Next: mysql-cluster-install-windows-initial-start, Prev: mysql-cluster-install-windows-binary, Up: mysql-cluster-install-windows 17.2.2.2 Compiling and Installing MySQL Cluster from Source on Windows ...................................................................... Oracle provides precompiled MySQL Cluster binaries for Windows which should be adequate for most users. However, if you wish, it is also possible to compile MySQL Cluster for Windows from source code. The procedure for doing this is almost identical to the procedure used to compile the standard MySQL Server binaries for Windows, and uses the same tools. However, there are two major differences: * To build MySQL Cluster, you must use the MySQL Cluster sources, which you can obtain from `http://dev.mysql.com/downloads/cluster/'. Attempting to build MySQL Cluster from the source code for the standard MySQL Server is likely not to be successful, and is not supported by Oracle. * You must configure the build using the `WITH_NDBCLUSTER_STORAGE_ENGINE' option in addition to any other build options you wish to use before creating the Visual Studio project files. Once you have run `configure.js' with the desired options, you can create the project files and build from them in the same manner as you do when compiling the standard MySQL Server. For more information, see *Note windows-source-build::. Prior to MySQL Cluster NDB 7.1.9, MySQL Cluster was not compatible with the *Note `InnoDB': innodb-storage-engine. Plugin; in earlier MySQL Cluster releases, only the version of *Note `InnoDB': innodb-storage-engine. supplied with the MySQL Server could be used. Beginning with MySQL Cluster NDB 7.1.9, you can build MySQL Cluster with *Note `InnoDB': innodb-storage-engine. storage engine or plugin support on Windows using `WITH_INNOBASE_STORAGE_ENGINE' with `configure.js'- Once the build process is complete, you can create a Zip archive containing the compiled binaries by running *Note `make_win_bin_dist': make-win-bin-dist. The MySQL Cluster binaries can be found in the `bin' directory of the resulting archive, which is equivalent to the `no-install' archive, and which can be installed and configured in the same manner. For basic information about how to accomplish these tasks, see *Note mysql-cluster-install-windows-binary::. On Windows, beginning with MySQL Cluster NDB 7.0.11, using `WITH_NDBCLUSTER_STORAGE_ENGINE' with `configure.js' causes *Note `ndbmtd.exe': mysql-cluster-programs-ndbmtd. to be built automatically, and to be found in the `bin' directory of the archive created by *Note `make_win_bin_dist': make-win-bin-dist. (It was not possible to build *Note `ndbmtd.exe': mysql-cluster-programs-ndbmtd. on Windows prior to MySQL Cluster NDB 7.0.11.)  File: manual.info, Node: mysql-cluster-install-windows-initial-start, Next: mysql-cluster-install-windows-service, Prev: mysql-cluster-install-windows-source, Up: mysql-cluster-install-windows 17.2.2.3 Initial Startup of MySQL Cluster on Windows .................................................... Once the MySQL Cluster executables and needed configuration files are in place, performing an initial start of the cluster is simply a matter of starting the MySQL Cluster executables for all nodes in the cluster. Each cluster node process must be started separately, and on the host computer where it resides. The management node should be started first, followed by the data nodes, and then finally by any SQL nodes. 1. On the management node host, issue the following command from the command line to start the management node process: C:\mysql\bin> ndb_mgmd 2010-06-23 07:53:34 [MgmtSrvr] INFO -- NDB Cluster Management Server. mysql-5.1.56-ndb-7.1.16 2010-06-23 07:53:34 [MgmtSrvr] INFO -- Reading cluster configuration from 'config.ini' The management node process continues to print logging output to the console. This is normal, because the management node is not running as a Windows service. (If you have used MySQL Cluster on a Unix-like platform such as Linux, you may notice that the management node's default behavior in this regard on Windows is effectively the opposite of its behavior on Unix systems, where it runs by default as a Unix daemon process. This behavior is also true of MySQL Cluster data node processes running on Windows.) For this reason, do not close the window in which *Note `ndb_mgmd.exe': mysql-cluster-programs-ndb-mgmd. is running; doing so kills the management node process. (See *Note mysql-cluster-install-windows-service::, where we show how to install and run MySQL Cluster processes as Windows services.) The required `-f' option tells the management node where to find the global configuration file (`config.ini'). The long form of this option is `--config-file'. *Important*: A MySQL Cluster management node caches the configuration data that it reads from `config.ini'; once it has created a configuration cache, it ignores the `config.ini' file on subsequent starts unless forced to do otherwise. This means that, if the management node fails to start due to an error in this file, you must make the management node re-read `config.ini' after you have corrected any errors in it. You can do this by starting *Note `ndb_mgmd.exe': mysql-cluster-programs-ndb-mgmd. with the `--reload' or `--initial' option on the command line. Either of these options works to refresh the configuration cache. It is not necessary or advisable to use either of these options in the management node's `my.ini' file. For additional information about options which can be used with *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd, see *Note mysql-cluster-programs-ndb-mgmd::, as well as *Note mysql-cluster-program-options-common::. 2. On each of the data node hosts, run the command shown here to start the data node processes: C:\mysql\bin> ndbd 2010-06-23 07:53:46 [ndbd] INFO -- Configuration fetched from 'localhost:1186', generation: 1 In each case, the first line of output from the data node process should resemble what is shown in the preceding example, and is followed by additional lines of logging output. As with the management node process, this is normal, because the data node is not running as a Windows service. For this reason, do not close the console window in which the data node process is running; doing so kills *Note `ndbd.exe': mysql-cluster-programs-ndbd. (For more information, see *Note mysql-cluster-install-windows-service::.) 3. Do not start the SQL node yet; it cannot connect to the cluster until the data nodes have finished starting, which may take some time. Instead, in a new console window on the management node host, start the MySQL Cluster management client *Note `ndb_mgm.exe': mysql-cluster-programs-ndb-mgm, which should be in `C:\mysql\bin' on the management node host. (Do not try to re-use the console window where *Note `ndb_mgmd.exe': mysql-cluster-programs-ndb-mgmd. is running by typing `CTRL'+`C', as this kills the management node.) The resulting output should look like this: C:\mysql\bin> ndb_mgm -- NDB Cluster -- Management Client -- ndb_mgm> When the prompt `ndb_mgm>' appears, this indicates that the management client is ready to receive MySQL Cluster management commands. You can observe the status of the data nodes as they start by entering `ALL STATUS' at the management client prompt. This command causes a running report of the data nodes's startup sequence, which should look something like this: ndb_mgm> ALL STATUS Connected to Management Server at: localhost:1186 Node 2: starting (Last completed phase 3) (mysql-5.1.56-ndb-7.1.16) Node 3: starting (Last completed phase 3) (mysql-5.1.56-ndb-7.1.16) Node 2: starting (Last completed phase 4) (mysql-5.1.56-ndb-7.1.16) Node 3: starting (Last completed phase 4) (mysql-5.1.56-ndb-7.1.16) Node 2: Started (version 7.1.16) Node 3: Started (version 7.1.16) ndb_mgm> *Note*: Commands issued in the management client are not case-sensitive; we use uppercase as the canonical form of these commands, but you are not required to observe this convention when inputting them into the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client. For more information, see *Note mysql-cluster-mgm-client-commands::. The output produced by `ALL STATUS' is likely to vary from what is shown here, according to the speed at which the data nodes are able to start, the release version number of the MySQL Cluster software you are using, and other factors. What is significant is that, when you see that both data nodes have started, you are ready to start the SQL node. You can leave *Note `ndb_mgm.exe': mysql-cluster-programs-ndb-mgm. running; it has no negative impact on the performance of the MySQL Cluster, and we use it in the next step to verify that the SQL node is connected to the cluster after you have started it. 4. On the computer designated as the SQL node host, open a console window and navigate to the directory where you unpacked the MySQL Cluster binaries (if you are following our example, this is `C:\mysql\bin'). Start the SQL node by invoking *Note `mysqld.exe': mysqld. from the command line, as shown here: C:\mysql\bin> mysqld --console The `--console' option causes logging information to be written to the console, which can be helpful in the event of problems. (Once you are satisfied that the SQL node is running in a satisfactory manner, you can stop it and restart it out without the `--console' option, so that logging is performed normally.) In the console window where the management client (*Note `ndb_mgm.exe': mysql-cluster-programs-ndb-mgm.) is running on the management node host, enter the `SHOW' command, which should produce output similar to what is shown here: ndb_mgm> SHOW Connected to Management Server at: localhost:1186 Cluster Configuration --------------------- [ndbd(NDB)] 2 node(s) id=2 @192.168.0.30 (Version: 5.1.56-ndb-7.1.16, Nodegroup: 0, Master) id=3 @192.168.0.40 (Version: 5.1.56-ndb-7.1.16, Nodegroup: 0) [ndb_mgmd(MGM)] 1 node(s) id=1 @192.168.0.10 (Version: 5.1.56-ndb-7.1.16) [mysqld(API)] 1 node(s) id=4 @192.168.0.20 (Version: 5.1.56-ndb-7.1.16) You can also verify that the SQL node is connected to the MySQL Cluster in the *Note `mysql': mysql. client (*Note `mysql.exe': mysql.) using the `SHOW ENGINE NDB STATUS' statement. You should now be ready to work with database objects and data using MySQL Cluster's *Note `NDBCLUSTER': mysql-cluster. storage engine. See *Note mysql-cluster-install-example-data::, for more information and examples. Beginning with MySQL Cluster NDB 7.0.16 and MySQL Cluster NDB 7.1.5, you can install *Note `ndb_mgmd.exe': mysql-cluster-programs-ndb-mgmd, *Note `ndbd.exe': mysql-cluster-programs-ndbd, and *Note `ndbmtd.exe': mysql-cluster-programs-ndbmtd. as Windows services. For information on how to do this, see *Note mysql-cluster-install-windows-service::).  File: manual.info, Node: mysql-cluster-install-windows-service, Prev: mysql-cluster-install-windows-initial-start, Up: mysql-cluster-install-windows 17.2.2.4 Installing MySQL Cluster Processes as Windows Services ............................................................... Once you are satisfied that MySQL Cluster is running as desired, you can--beginning with MySQL Cluster NDB 7.0.16 and MySQL Cluster NDB 7.1.5--install the management nodes and data nodes as Windows services, so that these processes are started and stopped automatically whenever Windows is started or stopped. This also makes it possible to control these processes from the command line with the appropriate `NET START' or `NET STOP' command, or using the Windows graphical `Services' utility. Installing programs as Windows services usually must be done using an account that has Administrator rights on the system. To install the management node as a service on Windows, invoke *Note `ndb_mgmd.exe': mysql-cluster-programs-ndb-mgmd. from the command line on the machine hosting the management node, using the `--install' option, as shown here: C:\> C:\mysql\bin\ndb_mgmd.exe --install Installing service 'MySQL Cluster Management Server' as '"C:\mysql\bin\ndbd.exe" "--service=ndb_mgmd"' Service successfully installed. *Important*: When installing a MySQL Cluster program as a Windows service, you should always specify the complete path; otherwise the service installation may fail with the error `The system cannot find the file specified'. The `--install' option must be used first, ahead of any other options that might be specified for *Note `ndb_mgmd.exe': mysql-cluster-programs-ndb-mgmd. However, it is preferable to specify such options in an options file instead. If your options file is not in one of the default locations as shown in the output of *Note `ndb_mgmd.exe': mysql-cluster-programs-ndb-mgmd. `--help', you can specify the location using the `--config-file' option. Now you should be able to start and stop the management server like this: C:\> NET START ndb_mgmd The MySQL Cluster Management Server service is starting. The MySQL Cluster Management Server service was started successfully. C:\> NET STOP ndb_mgmd The MySQL Cluster Management Server service is stopping.. The MySQL Cluster Management Server service was stopped successfully. You can also start or stop the management server as a Windows service using the descriptive name, as shown here: C:\> NET START 'MySQL Cluster Management Server' The MySQL Cluster Management Server service is starting. The MySQL Cluster Management Server service was started successfully. C:\> NET STOP 'MySQL Cluster Management Server' The MySQL Cluster Management Server service is stopping.. The MySQL Cluster Management Server service was stopped successfully. However, it is usually simpler to specify a short service name or to permit the default service name to be used when installing the service, and then reference that name when starting or stopping the service. To specify a service name other than `ndb_mgmd', append it to the `--install' option, as shown in this example: C:\> C:\mysql\bin\ndb_mgmd.exe --install=mgmd1 Installing service 'MySQL Cluster Management Server' as '"C:\mysql\bin\ndb_mgmd.exe" "--service=mgmd1"' Service successfully installed. Now you should be able to start or stop the service using the name you have specified, like this: C:\> NET START mgmd1 The MySQL Cluster Management Server service is starting. The MySQL Cluster Management Server service was started successfully. C:\> NET STOP mgmd1 The MySQL Cluster Management Server service is stopping.. The MySQL Cluster Management Server service was stopped successfully. To remove the management node service, invoke *Note `ndb_mgmd.exe': mysql-cluster-programs-ndb-mgmd. with the `--remove' option, as shown here: C:\> C:\mysql\bin\ndb_mgmd.exe --remove Removing service 'MySQL Cluster Management Server' Service successfully removed. If you installed the service using a service name other than the default, you can remove the service by passing this name as the value of the `--remove' option, like this: C:\> C:\mysql\bin\ndb_mgmd.exe --remove=mgmd1 Removing service 'mgmd1' Service successfully removed. Installation of a MySQL Cluster data node processs as a Windows service can be done in a similar fashion, using the `--install' option for *Note `ndbd.exe': mysql-cluster-programs-ndbd. (or *Note `ndbmtd.exe': mysql-cluster-programs-ndbmtd.), as shown here: C:\> C:\mysql\bin\ndbd.exe --install Installing service 'MySQL Cluster Data Node Daemon' as '"C:\mysql\bin\ndbd.exe" "--service=ndbd"' Service successfully installed. Now you can start or stop the data node using either the default service name or the descriptive name with `net start' or `net stop', as shown in the following example: C:\> NET START ndbd The MySQL Cluster Data Node Daemon service is starting. The MySQL Cluster Data Node Daemon service was started successfully. C:\> NET STOP ndbd The MySQL Cluster Data Node Daemon service is stopping.. The MySQL Cluster Data Node Daemon service was stopped successfully. C:\> NET START 'MySQL Cluster Data Node Daemon' The MySQL Cluster Data Node Daemon service is starting. The MySQL Cluster Data Node Daemon service was started successfully. C:\> NET STOP 'MySQL Cluster Data Node Daemon' The MySQL Cluster Data Node Daemon service is stopping.. The MySQL Cluster Data Node Daemon service was stopped successfully. To remove the data node service, invoke *Note `ndbd.exe': mysql-cluster-programs-ndbd. with the `--remove' option, as shown here: C:\> C:\mysql\bin\ndbd.exe --remove Removing service 'MySQL Cluster Data Node Daemon' Service successfully removed. As with *Note `ndb_mgmd.exe': mysql-cluster-programs-ndb-mgmd. (and *Note `mysqld.exe': mysqld.), when installing *Note `ndbd.exe': mysql-cluster-programs-ndbd. as a Windows service, you can also specify a name for the service as the value of `--install', and then use it when starting or stopping the service, like this: C:\> C:\mysql\bin\ndbd.exe --install=dnode1 Installing service 'dnode1' as '"C:\mysql\bin\ndbd.exe" "--service=dnode1"' Service successfully installed. C:\> NET START dnode1 The MySQL Cluster Data Node Daemon service is starting. The MySQL Cluster Data Node Daemon service was started successfully. C:\> NET STOP dnode1 The MySQL Cluster Data Node Daemon service is stopping.. The MySQL Cluster Data Node Daemon service was stopped successfully. If you specified a service name when installing the data node service, you can use this name when removing it as well, by passing it as the value of the `--remove' option, as shown here: C:\> C:\mysql\bin\ndbd.exe --remove=dnode1 Removing service 'dnode1' Service successfully removed. Installation of the SQL node as a Windows service, starting the service, stopping the service, and removing the service are done in a similar fashion, using *Note `mysqld': mysqld. `--install', `NET START', `NET STOP', and *Note `mysqld': mysqld. `--remove'. For additional information, see *Note windows-start-service::.  File: manual.info, Node: mysql-cluster-install-configuration, Next: mysql-cluster-install-first-start, Prev: mysql-cluster-install-windows, Up: mysql-cluster-installation 17.2.3 Initial Configuration of MySQL Cluster --------------------------------------------- For our four-node, four-host MySQL Cluster, it is necessary to write four configuration files, one per node host. * Each data node or SQL node requires a `my.cnf' file that provides two pieces of information: a _connectstring_ that tells the node where to find the management node, and a line telling the MySQL server on this host (the machine hosting the data node) to enable the *Note `NDBCLUSTER': mysql-cluster. storage engine. For more information on connectstrings, see *Note mysql-cluster-connectstring::. * The management node needs a `config.ini' file telling it how many replicas to maintain, how much memory to allocate for data and indexes on each data node, where to find the data nodes, where to save data to disk on each data node, and where to find any SQL nodes. Configuring the data nodes and SQL nodes The `my.cnf' file needed for the data nodes is fairly simple. The configuration file should be located in the `/etc' directory and can be edited using any text editor. (Create the file if it does not exist.) For example: shell> vi /etc/my.cnf *Note*: We show `vi' being used here to create the file, but any text editor should work just as well. For each data node and SQL node in our example setup, `my.cnf' should look like this: [mysqld] # Options for mysqld process: ndbcluster # run NDB storage engine ndb-connectstring=192.168.0.10 # location of management server [mysql_cluster] # Options for ndbd process: ndb-connectstring=192.168.0.10 # location of management server After entering the preceding information, save this file and exit the text editor. Do this for the machines hosting data node `A', data node `B', and the SQL node. *Important*: Once you have started a *Note `mysqld': mysqld. process with the *Note `NDBCLUSTER': mysql-cluster. and `ndb-connectstring' parameters in the `[mysqld]' in the `my.cnf' file as shown previously, you cannot execute any *Note `CREATE TABLE': create-table. or *Note `ALTER TABLE': alter-table. statements without having actually started the cluster. Otherwise, these statements will fail with an error. _This is by design_. Configuring the management node The first step in configuring the management node is to create the directory in which the configuration file can be found and then to create the file itself. For example (running as `root'): shell> mkdir /var/lib/mysql-cluster shell> cd /var/lib/mysql-cluster shell> vi config.ini For our representative setup, the `config.ini' file should read as follows: [ndbd default] # Options affecting ndbd processes on all data nodes: NoOfReplicas=2 # Number of replicas DataMemory=80M # How much memory to allocate for data storage IndexMemory=18M # How much memory to allocate for index storage # For DataMemory and IndexMemory, we have used the # default values. Since the "world" database takes up # only about 500KB, this should be more than enough for # this example Cluster setup. [tcp default] # TCP/IP options: portnumber=2202 # This the default; however, you can use any # port that is free for all the hosts in the cluster # Note: It is recommended that you do not specify the port # number at all and simply allow the default value to be used # instead [ndb_mgmd] # Management process options: hostname=192.168.0.10 # Hostname or IP address of MGM node datadir=/var/lib/mysql-cluster # Directory for MGM node log files [ndbd] # Options for data node "A": # (one [ndbd] section per data node) hostname=192.168.0.30 # Hostname or IP address datadir=/usr/local/mysql/data # Directory for this data node's data files [ndbd] # Options for data node "B": hostname=192.168.0.40 # Hostname or IP address datadir=/usr/local/mysql/data # Directory for this data node's data files [mysqld] # SQL node options: hostname=192.168.0.20 # Hostname or IP address # (additional mysqld connections can be # specified for this node for various # purposes such as running ndb_restore) *Note*: The `world' database can be downloaded from `http://dev.mysql.com/doc/', where it can be found listed under `Examples'. After all the configuration files have been created and these minimal options have been specified, you are ready to proceed with starting the cluster and verifying that all processes are running. We discuss how this is done in *Note mysql-cluster-install-first-start::. For more detailed information about the available MySQL Cluster configuration parameters and their uses, see *Note mysql-cluster-config-file::, and *Note mysql-cluster-configuration::. For configuration of MySQL Cluster as relates to making backups, see *Note mysql-cluster-backup-configuration::. *Note*: The default port for Cluster management nodes is 1186; the default port for data nodes is 2202. However, the cluster can automatically allocate ports for data nodes from those that are already free.  File: manual.info, Node: mysql-cluster-install-first-start, Next: mysql-cluster-install-example-data, Prev: mysql-cluster-install-configuration, Up: mysql-cluster-installation 17.2.4 Initial Startup of MySQL Cluster --------------------------------------- Starting the cluster is not very difficult after it has been configured. Each cluster node process must be started separately, and on the host where it resides. The management node should be started first, followed by the data nodes, and then finally by any SQL nodes: 1. On the management host, issue the following command from the system shell to start the management node process: shell> ndb_mgmd -f /var/lib/mysql-cluster/config.ini *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. must be told where to find its configuration file, using the `-f' or `--config-file' option. (See *Note mysql-cluster-programs-ndb-mgmd::, for details.) For additional options which can be used with *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd, see *Note mysql-cluster-program-options-common::. 2. On each of the data node hosts, run this command to start the *Note `ndbd': mysql-cluster-programs-ndbd. process: shell> ndbd 3. If you used RPM files to install MySQL on the cluster host where the SQL node is to reside, you can (and should) use the supplied startup script to start the MySQL server process on the SQL node. If all has gone well, and the cluster has been set up correctly, the cluster should now be operational. You can test this by invoking the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. management node client. The output should look like that shown here, although you might see some slight differences in the output depending upon the exact version of MySQL that you are using: shell> ndb_mgm -- NDB Cluster -- Management Client -- ndb_mgm> SHOW Connected to Management Server at: localhost:1186 Cluster Configuration --------------------- [ndbd(NDB)] 2 node(s) id=2 @192.168.0.30 (Version: 5.1.56-ndb-7.1.16, Nodegroup: 0, Master) id=3 @192.168.0.40 (Version: 5.1.56-ndb-7.1.16, Nodegroup: 0) [ndb_mgmd(MGM)] 1 node(s) id=1 @192.168.0.10 (Version: 5.1.56-ndb-7.1.16) [mysqld(API)] 1 node(s) id=4 @192.168.0.20 (Version: 5.1.56-ndb-7.1.16) The SQL node is referenced here as `[mysqld(API)]', which reflects the fact that the *Note `mysqld': mysqld. process is acting as a MySQL Cluster API node. *Note*: The IP address shown for a given MySQL Cluster SQL or other API node in the output of `SHOW' is the address used by the SQL or API node to connect to the cluster data nodes, and not to any management node. You should now be ready to work with databases, tables, and data in MySQL Cluster. See *Note mysql-cluster-install-example-data::, for a brief discussion.  File: manual.info, Node: mysql-cluster-install-example-data, Next: mysql-cluster-install-shutdown-restart, Prev: mysql-cluster-install-first-start, Up: mysql-cluster-installation 17.2.5 MySQL Cluster Example with Tables and Data ------------------------------------------------- *Note*: The information in this section applies to MySQL Cluster running on both Unix and Windows platforms. Working with database tables and data in MySQL Cluster is not much different from doing so in standard MySQL. There are two key points to keep in mind: * For a table to be replicated in the cluster, it must use the *Note `NDBCLUSTER': mysql-cluster. storage engine. To specify this, use the `ENGINE=NDBCLUSTER' or `ENGINE=NDB' option when creating the table: CREATE TABLE TBL_NAME (COL_NAME COLUMN_DEFINITIONS) ENGINE=NDBCLUSTER; Alternatively, for an existing table that uses a different storage engine, use *Note `ALTER TABLE': alter-table. to change the table to use *Note `NDBCLUSTER': mysql-cluster.: ALTER TABLE TBL_NAME ENGINE=NDBCLUSTER; * Every *Note `NDBCLUSTER': mysql-cluster. table has a primary key. If no primary key is defined by the user when a table is created, the *Note `NDBCLUSTER': mysql-cluster. storage engine automatically generates a hidden one. Such a key takes up space just as does any other table index. (It is not uncommon to encounter problems due to insufficient memory for accommodating these automatically created indexes.) If you are importing tables from an existing database using the output of *Note `mysqldump': mysqldump, you can open the SQL script in a text editor and add the `ENGINE' option to any table creation statements, or replace any existing `ENGINE' options. Suppose that you have the `world' sample database on another MySQL server that does not support MySQL Cluster, and you want to export the `City' table: shell> mysqldump --add-drop-table world City > city_table.sql The resulting `city_table.sql' file will contain this table creation statement (and the *Note `INSERT': insert. statements necessary to import the table data): DROP TABLE IF EXISTS `City`; CREATE TABLE `City` ( `ID` int(11) NOT NULL auto_increment, `Name` char(35) NOT NULL default '', `CountryCode` char(3) NOT NULL default '', `District` char(20) NOT NULL default '', `Population` int(11) NOT NULL default '0', PRIMARY KEY (`ID`) ) ENGINE=MyISAM DEFAULT CHARSET=latin1; INSERT INTO `City` VALUES (1,'Kabul','AFG','Kabol',1780000); INSERT INTO `City` VALUES (2,'Qandahar','AFG','Qandahar',237500); INSERT INTO `City` VALUES (3,'Herat','AFG','Herat',186800); (REMAINING INSERT STATEMENTS OMITTED) You need to make sure that MySQL uses the *Note `NDBCLUSTER': mysql-cluster. storage engine for this table. There are two ways that this can be accomplished. One of these is to modify the table definition _before_ importing it into the Cluster database. Using the `City' table as an example, modify the `ENGINE' option of the definition as follows: DROP TABLE IF EXISTS `City`; CREATE TABLE `City` ( `ID` int(11) NOT NULL auto_increment, `Name` char(35) NOT NULL default '', `CountryCode` char(3) NOT NULL default '', `District` char(20) NOT NULL default '', `Population` int(11) NOT NULL default '0', PRIMARY KEY (`ID`) ) *ENGINE=NDBCLUSTER* DEFAULT CHARSET=latin1; INSERT INTO `City` VALUES (1,'Kabul','AFG','Kabol',1780000); INSERT INTO `City` VALUES (2,'Qandahar','AFG','Qandahar',237500); INSERT INTO `City` VALUES (3,'Herat','AFG','Herat',186800); (REMAINING INSERT STATEMENTS OMITTED) This must be done for the definition of each table that is to be part of the clustered database. The easiest way to accomplish this is to do a search-and-replace on the file that contains the definitions and replace all instances of `TYPE=ENGINE_NAME' or `ENGINE=ENGINE_NAME' with `ENGINE=NDBCLUSTER'. If you do not want to modify the file, you can use the unmodified file to create the tables, and then use *Note `ALTER TABLE': alter-table. to change their storage engine. The particulars are given later in this section. Assuming that you have already created a database named `world' on the SQL node of the cluster, you can then use the *Note `mysql': mysql. command-line client to read `city_table.sql', and create and populate the corresponding table in the usual manner: shell> mysql world < city_table.sql It is very important to keep in mind that the preceding command must be executed on the host where the SQL node is running (in this case, on the machine with the IP address `192.168.0.20'). To create a copy of the entire `world' database on the SQL node, use *Note `mysqldump': mysqldump. on the noncluster server to export the database to a file named `world.sql'; for example, in the `/tmp' directory. Then modify the table definitions as just described and import the file into the SQL node of the cluster like this: shell> mysql world < /tmp/world.sql If you save the file to a different location, adjust the preceding instructions accordingly. Running *Note `SELECT': select. queries on the SQL node is no different from running them on any other instance of a MySQL server. To run queries from the command line, you first need to log in to the MySQL Monitor in the usual way (specify the `root' password at the `Enter password:' prompt): shell> mysql -u root -p Enter password: Welcome to the MySQL monitor. Commands end with ; or \g. Your MySQL connection id is 1 to server version: 5.1.56-ndb-7.1.16 Type 'help;' or '\h' for help. Type '\c' to clear the buffer. mysql> We simply use the MySQL server's `root' account and assume that you have followed the standard security precautions for installing a MySQL server, including setting a strong `root' password. For more information, see *Note default-privileges::. It is worth taking into account that Cluster nodes do _not_ make use of the MySQL privilege system when accessing one another. Setting or changing MySQL user accounts (including the `root' account) effects only applications that access the SQL node, not interaction between nodes. See *Note mysql-cluster-security-mysql-privileges::, for more information. If you did not modify the `ENGINE' clauses in the table definitions prior to importing the SQL script, you should run the following statements at this point: mysql> USE world; mysql> ALTER TABLE City ENGINE=NDBCLUSTER; mysql> ALTER TABLE Country ENGINE=NDBCLUSTER; mysql> ALTER TABLE CountryLanguage ENGINE=NDBCLUSTER; Selecting a database and running a `SELECT' query against a table in that database is also accomplished in the usual manner, as is exiting the MySQL Monitor: mysql> USE world; mysql> SELECT Name, Population FROM City ORDER BY Population DESC LIMIT 5; +-----------+------------+ | Name | Population | +-----------+------------+ | Bombay | 10500000 | | Seoul | 9981619 | | Sa~o Paulo | 9968485 | | Shanghai | 9696300 | | Jakarta | 9604900 | +-----------+------------+ 5 rows in set (0.34 sec) mysql> \q Bye shell> Applications that use MySQL can employ standard APIs to access *Note `NDB': mysql-cluster. tables. It is important to remember that your application must access the SQL node, and not the management or data nodes. This brief example shows how we might execute the *Note `SELECT': select. statement just shown by using the PHP 5.X `mysqli' extension running on a Web server elsewhere on the network: SIMPLE mysqli SELECT query($query) ) { ?> fetch_object()) printf("\n \n\n", $row->Name, $row->Population); ?> Affected rows: %d

\n", $link->affected_rows); } else # otherwise, tell us what went wrong echo mysqli_error(); # free the result set and the mysqli connection object $result->close(); $link->close(); ?> We assume that the process running on the Web server can reach the IP address of the SQL node. In a similar fashion, you can use the MySQL C API, Perl-DBI, Python-mysql, or MySQL Connectors to perform the tasks of data definition and manipulation just as you would normally with MySQL.  File: manual.info, Node: mysql-cluster-install-shutdown-restart, Next: mysql-cluster-upgrade-downgrade, Prev: mysql-cluster-install-example-data, Up: mysql-cluster-installation 17.2.6 Safe Shutdown and Restart of MySQL Cluster ------------------------------------------------- To shut down the cluster, enter the following command in a shell on the machine hosting the management node: shell> ndb_mgm -e shutdown The `-e' option here is used to pass a command to the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client from the shell. (See *Note mysql-cluster-program-options-common::, for more information about this option.) The command causes the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm, *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd, and any *Note `ndbd': mysql-cluster-programs-ndbd. or *Note `ndbmtd': mysql-cluster-programs-ndbmtd. processes to terminate gracefully. Any SQL nodes can be terminated using *Note `mysqladmin shutdown': mysqladmin. and other means. On Windows platforms, assuming that you have installed the SQL node as a Windows service, you can use `NET STOP MYSQL'. To restart the cluster on Unix platforms, run these commands: * On the management host (`192.168.0.10' in our example setup): shell> ndb_mgmd -f /var/lib/mysql-cluster/config.ini * On each of the data node hosts (`192.168.0.30' and `192.168.0.40'): shell> ndbd * Use the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client to verify that both data nodes have started successfully. * On the SQL host (`192.168.0.20'): shell> mysqld_safe & On Windows platforms, assuming that you have installed all MySQL Cluster processes as Windows services using the default service names (see *Note mysql-cluster-install-windows-service::), you can restart the cluster as follows: * On the management host (`192.168.0.10' in our example setup), execute the following command: C:\> NET START ndb_mgmd * On each of the data node hosts (`192.168.0.30' and `192.168.0.40'), execute the following command: C:\> NET START ndbd * On the management node host, use the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client to verify that the management node and both data nodes have started successfully (see *Note mysql-cluster-install-windows-initial-start::). * On the SQL node host (`192.168.0.20'), execute the following command: C:\> NET START mysql In a production setting, it is usually not desirable to shut down the cluster completely. In many cases, even when making configuration changes, or performing upgrades to the cluster hardware or software (or both), which require shutting down individual host machines, it is possible to do so without shutting down the cluster as a whole by performing a _rolling restart_ of the cluster. For more information about doing this, see *Note mysql-cluster-rolling-restart::.  File: manual.info, Node: mysql-cluster-upgrade-downgrade, Prev: mysql-cluster-install-shutdown-restart, Up: mysql-cluster-installation 17.2.7 Upgrading and Downgrading MySQL Cluster ---------------------------------------------- * Menu: * mysql-cluster-upgrade-downgrade-compatibility-7.x:: Upgrade and downgrade compatibility: MySQL Cluster NDB 7.x * mysql-cluster-upgrade-downgrade-compatibility-6.x:: Upgrade and Downgrade Compatibility: MySQL Cluster NDB 6.x * mysql-cluster-upgrade-downgrade-compatibility-5.1:: Upgrade and downgrade compatibility: MySQL 5.1 This section provides information about MySQL Cluster software and table file compatibility between MySQL 5.1.23 and earlier, MySQL Cluster NDB 6.x, and MySQL Cluster NDB 7.x releases with regard to performing upgrades and downgrades as well as compatibility matrices and notes. You are expected already to be familiar with installing and configuring a MySQL Cluster prior to attempting an upgrade or downgrade. See *Note mysql-cluster-configuration::. *Important*: Only compatibility between MySQL versions with regard to *Note `NDBCLUSTER': mysql-cluster. is taken into account in this section, and there are likely other issues to be considered. _As with any other MySQL software upgrade or downgrade, you are strongly encouraged to review the relevant portions of the MySQL Manual for the MySQL versions from which and to which you intend to migrate, before attempting an upgrade or downgrade of the MySQL Cluster software_. See *Note upgrading::. For information about upgrades and downgrades to, from, and between different releases of MySQL Cluster NDB 7.0 and MySQL Cluster NDB 7.1, see *Note mysql-cluster-upgrade-downgrade-compatibility-7.x::. For information about upgrades and downgrades to, from, and between different releases of MySQL Cluster NDB 6.1, MySQL Cluster NDB 6.2, and MySQL Cluster NDB 6.3, see *Note mysql-cluster-upgrade-downgrade-compatibility-6.x::. For information about upgrades and downgrades to, from, and between different editions of MySQL Cluster as found in standard MySQL 5.1.23 and earlier releases, see *Note mysql-cluster-upgrade-downgrade-compatibility-5.1::. *Important*: Only compatibility between MySQL versions with regard to *Note `NDBCLUSTER': mysql-cluster. is taken into account in this section, and there are likely other issues to be considered. _As with any other MySQL software upgrade or downgrade, you are strongly encouraged to review the relevant portions of the MySQL Manual for the MySQL versions from which and to which you intend to migrate, before attempting an upgrade or downgrade of the MySQL Cluster software_. See *Note upgrading::.  File: manual.info, Node: mysql-cluster-upgrade-downgrade-compatibility-7.x, Next: mysql-cluster-upgrade-downgrade-compatibility-6.x, Prev: mysql-cluster-upgrade-downgrade, Up: mysql-cluster-upgrade-downgrade 17.2.7.1 Upgrade and downgrade compatibility: MySQL Cluster NDB 7.x ................................................................... The table shown here provides information on MySQL Cluster upgrade and downgrade compatibility among different releases of MySQL Cluster NDB 7.0 and 7.1. Additional notes about upgrades and downgrades to, from, or within the MySQL Cluster NDB 7.x release series can be found immediately following the table. MySQL Cluster upgrade/downgrade compatibility, MySQL Cluster NDB 7.x * Notes: MySQL Cluster NDB 7.x * Versions supported Online upgrades from any MySQL Cluster NDB 7.0 release up to and including MySQL Cluster NDB 7.0.4 (as well as all early releases numbered NDB 6.4.x) to MySQL Cluster NDB 7.0.5 or later are not possible. Upgrades to MySQL Cluster NDB 7.0.6 or later from MySQL Cluster NDB 6.3.8 or a later MySQL Cluster NDB 6.3 release, or from MySQL Cluster NDB 7.0.5 or later, are supported. (Bug#44294) Upgrading `ndbd' to `ndbmtd' When upgrading online from a MySQL Cluster NDB 6.3 release to a MySQL Cluster NDB 7.0 release, you should not try to upgrade the data nodes from *Note `ndbd': mysql-cluster-programs-ndbd. to *Note `ndbmtd': mysql-cluster-programs-ndbmtd. at the same time. Instead, perform the upgrade using the new *Note `ndbd': mysql-cluster-programs-ndbd. executable (from the MySQL Cluster NDB 7.0.x distribution to which you are upgrading) to replace the one in use on the data nodes. Once the version upgrade is complete, you can perform a second (online) upgrade to replace the data node executables with *Note `ndbmtd': mysql-cluster-programs-ndbmtd. from the MySQL Cluster NDB 7.0.x distribution. Changes in default values In MySQL Cluster NDB 7.0.4, the default values for a number of MySQL Cluster configuration parameters relating to memory usage and buffering changed (see *Note mysql-cluster-news-5-1-32-ndb-7-0-4::, for a list of the parameters whose defaults changed). For this reason, you may encounter issues if you try to use a configuration that does not explicitly define each of these buffers (because it was developed for a previous version of MySQL Cluster), `SendBufferMemory' and `ReceiveBufferMemory' in particular. Other known issues include the following: * Prior to MySQL Cluster NDB 7.0.7, DML statements failed if executed while performing an online upgrade from a MySQL Cluster NDB 6.3 release. (Bug#45917) * Following an upgrade from any MySQL Cluster NDB 6.3.x release to MySQL Cluster NDB 7.0.6, DDL and backup operations failed. This issue was resolved in MySQL Cluster NDB 7.0.7. (Bug#46494, Bug#46563) * In some cases, there could be problems with online upgrades from MySQL Cluster NDB 6.3 releases to MySQL Cluster NDB 7.0 releases due to a previous change in the signalling format used between nodes. This issue was corrected in MySQL Cluster NDB 7.0.9. * Once an *Note `NDB': mysql-cluster. table had an *Note `ALTER ONLINE TABLE': alter-table. operation performed on it using a MySQL Cluster NDB 6.3.x release, it could not be upgraded online to MySQL Cluster NDB 7.0. This issue was resolved in MySQL Cluster NDB 7.0.8. (See Bug#47542.) * Following an upgrade from MySQL Cluster NDB 6.3 to MySQL Cluster NDB 7.0, if there were any tables having unique indexes prior to the upgrade, attempts to create unique indexes failed. This could also occur when performing offline *Note `ALTER TABLE': alter-table. operations on tables having indexes that were not dropped as a result of the *Note `ALTER TABLE': alter-table. This issue was due to a change in the way that *Note `NDB': mysql-cluster. tracked unique indexes internally, and was resolved in MySQL Cluster NDB 7.0.9. (Bug#48416) For upgrades to MySQL Cluster NDB 7.0 releases prior to version 7.0.9, a workaround is available: Following the upgrade, execute a _second_ rolling restart of the cluster before before performing any *Note `ALTER TABLE': alter-table. operations involving indexes. * Due to an issue discovered after the release of MySQL Cluster NDB 7.0.10 (Bug#50433), it is not possible to perform an online upgrade from MySQL Cluster NDB 7.0.9b and earlier MySQL Cluster NDB 7.0 releases to MySQL Cluster NDB 7.0.10. Instead, you should upgrade your MySQL Cluster NDB 7.0 installation directly to MySQL Cluster NDB 7.0.11 or later. This issue did not appear to affect MySQL Cluster NDB 6.3, and it should be possible to upgrade online from MySQL Cluster NDB 6.3 to MySQL Cluster NDB 7.0.10 without any problems other than those noted previously. * It was not possible to perform an online upgrade from a MySQL Cluster NDB 6.3 or 7.0 release to MySQL Cluster NDB 7.1.0 or 7.1.1. This issue was fixed in MySQL Cluster NDB 7.1.2 (see Bug#51429). * Following an upgrade to MySQL Cluster NDB 7.0.15 or later (MySQL Cluster NDB 7.0), or to MySQL Cluster NDB 7.1.4 or later (MySQL Cluster NDB 7.1), a table created in a previous version of MySQL Cluster does _not_ automatically support *Note `NDB': mysql-cluster.-native default values. Such a table continues to use default values supplied by the MySQL server until it is upgraded by performing an offline *Note `ALTER TABLE': alter-table. on it. When upgrading to a MySQL Cluster release that supports native default values from a MySQL Cluster release that does not, you should not attempt to create any new tables until all data nodes are using the new *Note `ndbd': mysql-cluster-programs-ndbd. or *Note `ndbmtd': mysql-cluster-programs-ndbmtd. binaries. This is because the older binaries do not provide support for native default values. *Important*: Tables created with native default value support cannot be used with versions of MySQL Cluster that do not support native default values. * Due to issues discovered shortly after release, MySQL Cluster NDB 7.0.20 was withdrawn and replaced with MySQL Cluster NDB 7.0.20a. Users of MySQL Cluster NDB 7.0.19 and previous MySQL Cluster NDB 7.0 releases should upgrade to MySQL Cluster NDB 7.0.20a, or to a later MySQL Cluster NDB 7.0 release. See *Note mysql-cluster-news-5-1-51-ndb-7-0-20a::, for more information. Due to issues discovered shortly after release, MySQL Cluster NDB 7.1.9 was withdrawn and replaced with MySQL Cluster NDB 7.1.9a. Users of MySQL Cluster NDB 7.1.8 and previous MySQL Cluster NDB 7.1 releases should upgrade to MySQL Cluster NDB 7.1.9a, or to a later MySQL Cluster NDB 7.1 release. See *Note mysql-cluster-news-5-1-51-ndb-7-1-9a::, for more information. * When performing an online upgrade or downgrade between MySQL Cluster NDB 7.1.8 or earlier and a later release up to and including MySQL Cluster NDB 7.1.14, you must upgrade or downgrade the data nodes before upgrading or downgrading any SQL nodes; otherwise *Note `mysql_upgrade': mysql-upgrade. fails on the SQL nodes due to differences between *Note `ndbinfo': mysql-cluster-ndbinfo. tables used in the `old' and `new' versions of the MySQL Cluster software. You should also upgrade or downgrade the data nodes prior to the SQL nodes when performing an online upgrade or downgrade between MySQL Cluster NDB 7.1 releases where either of the versions involved is MySQL Cluster NDB 7.1.14 or earlier, and where one or more *Note `ndbinfo': mysql-cluster-ndbinfo. tables has more, fewer, or differing columns between the two versions. This issue is resolved in MySQL Cluster NDB 7.1.15. (Bug#11885602)  File: manual.info, Node: mysql-cluster-upgrade-downgrade-compatibility-6.x, Next: mysql-cluster-upgrade-downgrade-compatibility-5.1, Prev: mysql-cluster-upgrade-downgrade-compatibility-7.x, Up: mysql-cluster-upgrade-downgrade 17.2.7.2 Upgrade and Downgrade Compatibility: MySQL Cluster NDB 6.x ................................................................... The table shown here provides information on MySQL Cluster upgrade and downgrade compatibility among different releases of MySQL Cluster NDB 6.1, 6.2, and 6.3. Additional notes about upgrades and downgrades to, from, or within the MySQL Cluster NDB 6.x release series can be found immediately following the table. MySQL Cluster upgrade/downgrade compatibility, MySQL Cluster NDB 6.x * Notes: MySQL Cluster NDB 6.1 * Availability of older releases MySQL Cluster NDB 6.1 is no longer in production; information about this series of releases is of historical interest only. MySQL Cluster NDB 6.2 is still available, but is no longer supported in new deployments. If you are still using a MySQL Cluster NDB 6.1 or MySQL Cluster NDB 6.2 release, you should upgrade to the most recent MySQL Cluster NDB 7.0 or MySQL Cluster NDB 7.1 release as soon as possible. * It is not possible to upgrade from MySQL Cluster NDB 6.1.2 (or an older 6.1 release) directly to 6.1.4 or a newer NDB 6.1 release, or to downgrade from 6.1.4 (or a newer 6.1 release) directly to 6.1.2 or an older NDB 6.1 release; in either case, you must upgrade or downgrade to MySQL Cluster NDB 6.1.3 first. * It is not possible to perform an online downgrade from MySQL Cluster NDB 6.1.8 (or a newer 6.1 release) to MySQL Cluster NDB 6.1.7 (or an older 6.1 release). * MySQL Cluster NDB 6.1.6 and 6.1.18 were not released. * It is not possible to perform an online upgrade or downgrade between MySQL Cluster NDB 6.2 and any previous release series (including mainline MySQL 5.1 and MySQL Cluster NDB 6.1); it is necessary to perform a dump and reload. However, it should be possible to perform online upgrades or downgrades between any MySQL Cluster NDB 6.2 release and any MySQL Cluster NDB 6.3 release up to and including 6.3.7. * Notes: MySQL Cluster NDB 6.2 and MySQL Cluster NDB 6.3 * Intenral column specification changes The internal specifications for columns in *Note `NDB': mysql-cluster. tables changed in MySQL Cluster NDB 6.1.17 and 6.2.1 to enable compatibility with later MySQL Cluster releases implementing online adding and dropping of columns (MySQL 5.1.17 through MySQL 5.1.23; MySQL Cluster NDB 6.2.3 and later; MySQL Cluster NDB 6.3.3 and later). This change is not backward-compatible with earlier MySQL Server or MySQL Cluster releases. To make tables created in earlier versions compatible with online adding and dropping of columns in later versions, it is necessary to force MySQL Cluster to convert the tables to the new format by following this procedure following an upgrade: 1. Upgrade the MySQL Cluster software on all data, management, and SQL nodes 2. Back up all *Note `NDB': mysql-cluster. tables 3. Shut down the cluster (all data, management, and SQL nodes) 4. Restart the cluster, starting all data nodes with the `--initial' option (to clear and rebuild the data node file systems) 5. Restore the tables from backup To minimize possible later difficulties, it is strongly advised that the procedure outlined above be followed as soon as possible after to upgrading between the versions indicated. The procedure is _not_ necessary for *Note `NDBCLUSTER': mysql-cluster. tables created in any of the following versions: * MySQL Cluster NDB 6.1.8 or a later MySQL Cluster NDB 6.1 release * MySQL Cluster 6.2.1 or a later MySQL Cluster NDB 6.2 release * Any MySQL Cluster NDB 6.3 release (or later MySQL Cluster release series) Tables created in the versions listed previously (or later versions, as indicated) are already compatible with adding and dropping of columns online (as implemented beginning with MySQL Cluster NDB 6.2.5 and MySQL Cluster NDB 6.3.3). Additional issues encountered when upgrading or downgrading to or from MySQL Cluster NDB 6.2 and MySQL Cluster NDB 6.3 releases are listed here: * It was not possible to perform an online upgrade between any MySQL Cluster NDB 6.2 release and MySQL Cluster NDB 6.3.8 and later MySQL Cluster 6.3 releases. This issue was fixed in MySQL Cluster NDB 6.3.21. (Bug#41435) * Online downgrades between MySQL Cluster NDB 6.2.5 and earlier releases are not supported. * Online downgrades between MySQL Cluster NDB 6.3.8 and earlier releases are not supported.  File: manual.info, Node: mysql-cluster-upgrade-downgrade-compatibility-5.1, Prev: mysql-cluster-upgrade-downgrade-compatibility-6.x, Up: mysql-cluster-upgrade-downgrade 17.2.7.3 Upgrade and downgrade compatibility: MySQL 5.1 ....................................................... The table shown here provides information on MySQL Cluster upgrade and downgrade compatibility among different releases of MySQL 5.1 prior to MySQL 5.1.24. Additional notes about upgrades and downgrades to, from, or within the MySQL 5.1 release series can be found immediately following the table. MySQL Cluster upgrade/downgrade compatibility, MySQL 5.1 * Notes: MySQL 5.1 * * MySQL 5.1.3 was the first public release in this series. * Direct upgrades or downgrades between MySQL Cluster 5.0 and 5.1 are not supported; you must dump all *Note `NDBCLUSTER': mysql-cluster. tables using *Note `mysqldump': mysqldump, install the new version of the software, and then reload the tables from the dump. * You cannot downgrade a MySQL Cluster based on MySQL 5.1.6 or later and using Disk Data tables to MySQL 5.1.5 or earlier unless you convert all such tables to in-memory *Note `NDB': mysql-cluster. tables first. * MySQL 5.1.8, MySQL 5.1.10, and MySQL 5.1.13 were not released. * Online cluster upgrades and downgrades between MySQL 5.1.11 (or an earlier version) and 5.1.12 (or a later version) are not possible due to major changes in the cluster file system. In such cases, you must perform a backup or dump, upgrade (or downgrade) the software, start each data node with `--initial', and then restore from the backup or dump. You can use native *Note `NDB': mysql-cluster. backup and restore, or *Note `mysqldump': mysqldump. and *Note `LOAD DATA INFILE': load-data. for this purpose. * Online downgrades from MySQL 5.1.14 or later to versions previous to 5.1.14 are not supported due to incompatible changes in the cluster system tables. MySQL Cluster Replication: changes in `ndb_apply_status' Online upgrades from MySQL 5.1.17 and earlier to 5.1.18 and later MySQL 5.1.x releases are not supported for clusters using replication due to incompatible changes in the `mysql.ndb_apply_status' table. (Online upgrades from MySQL 5.1 to MySQL Cluster NDB 6.2 and later are not supported, as discussed elsewhere in this section.) However, it should not be necessary to shut down the cluster entirely, if you follow this modified rolling restart procedure: 1. Stop the management server, update the management server software, then start the management server again. For multiple management servers, repeat this step for each management server in turn. 2. For each data node in turn: Stop the data node, update the data node daemon (in MySQL Cluster NDB 7.0 and later, this can be either *Note `ndbd': mysql-cluster-programs-ndbd. or *Note `ndbmtd': mysql-cluster-programs-ndbmtd.) with the new version, then restart the data node. It should not be necessary to use `--initial' when restarting any of the data nodes after updating the software. 3. Stop _all_ SQL nodes. Upgrade the existing MySQL server installations to the new version on all SQL nodes, then restart them. It is not necessary to start them one at a time after upgrading the MySQL server software, but _there must be a time when none of them is running before starting any of them again using the 5.1.18 (or later) *Note `mysqld': mysqld._. Otherwise--due to the fact that `mysql.ndb_apply_status' uses the *Note `NDB': mysql-cluster. storage engine and is thus shared between all SQL nodes--there may be conflicts between the old and new versions of the table on different SQL nodes. You can find more information about the changes to `ndb_apply_status' in *Note mysql-cluster-replication-schema::. *Note*: You should upgrade the MySQL Cluster software on each node using the same method by which it was originally installed. See *Note mysql-cluster-installation::, for more information. As with any other MySQL Cluster version upgrade, you should also update the MySQL Cluster management client (*Note `ndb_mgm': mysql-cluster-programs-ndb-mgm.) and other MySQL Cluster client programs such as *Note `ndb_config': mysql-cluster-programs-ndb-config. and *Note `ndb_error_reporter': mysql-cluster-programs-ndb-error-reporter.; however, this does not have to be done in any particular order. Internal column specification changes The internal specifications for columns in *Note `NDBCLUSTER': mysql-cluster. tables changed in MySQL 5.1.18 to enable compatibility with later MySQL Cluster releases that permit online adding and dropping of columns. _This change is not backward-compatible with earlier MySQL versions_. To make tables created in MySQL 5.1.17 and earlier compatible with online adding and dropping of columns (available beginning with beginning with MySQL Cluster NDB 6.2.5 and MySQL Cluster NDB 6.3.3--see *Note alter-table::, for more information), it is necessary to force MySQL 5.1.18 and later to convert the tables to the new format by following this procedure: 1. Back up all *Note `NDBCLUSTER': mysql-cluster. tables. 2. Upgrade the MySQL Cluster software on all data, management, and SQL nodes. 3. Shut down the cluster completely (this includes all data, management, and API or SQL nodes). 4. Restart the cluster, starting all data nodes with the `--initial' option (to clear and rebuild the data node file systems). 5. Restore the *Note `NDBCLUSTER': mysql-cluster. tables from backup. It is not necessary to follow this procedure for *Note `NDBCLUSTER': mysql-cluster. tables created in MySQL 5.1.18 and later; such tables are already compatible with online adding and dropping of columns (as implemented beginning with MySQL Cluster NDB 6.2.5 and MySQL Cluster NDB 6.3.2). To minimize possible later difficulties, it is strongly advised that the procedure outlined above be followed as soon as possible after to upgrading from MySQL 5.1.17 or earlier to MySQL 5.1.18 or later. Information about how this change effects users of MySQL Cluster NDB 6.x and 7.x is provided later in this section. MySQL Cluster not supported in MySQL Server 5.1.24 and later MySQL Cluster is not supported in standard MySQL 5.1 releases beginning with MySQL 5.1.24. If you are using MySQL Cluster in a standard MySQL 5.1 release, you should upgrade to the most recent MySQL Cluster NDB 7.0 or MySQL Cluster NDB 7.1 release.  File: manual.info, Node: mysql-cluster-configuration, Next: mysql-cluster-programs, Prev: mysql-cluster-installation, Up: mysql-cluster 17.3 MySQL Cluster Configuration ================================ * Menu: * mysql-cluster-quick:: Quick Test Setup of MySQL Cluster * mysql-cluster-config-file:: MySQL Cluster Configuration Files * mysql-cluster-params-overview:: Overview of MySQL Cluster Configuration Parameters * mysql-cluster-options-variables:: MySQL Server Options and Variables for MySQL Cluster * mysql-cluster-interconnects:: Using High-Speed Interconnects with MySQL Cluster A MySQL server that is part of a MySQL Cluster differs in one chief respect from a normal (nonclustered) MySQL server, in that it employs the *Note `NDBCLUSTER': mysql-cluster. storage engine. This engine is also referred to simply as *Note `NDB': mysql-cluster, and the two forms of the name are synonymous. To avoid unnecessary allocation of resources, the server is configured by default with the *Note `NDB': mysql-cluster. storage engine disabled. To enable *Note `NDB': mysql-cluster, you must modify the server's `my.cnf' configuration file, or start the server with the `--ndbcluster' option. For more information about `--ndbcluster' and other MySQL server options specific to MySQL Cluster, see *Note mysql-cluster-program-options-mysqld::. The MySQL server is a part of the cluster, so it also must know how to access an MGM node to obtain the cluster configuration data. The default behavior is to look for the MGM node on `localhost'. However, should you need to specify that its location is elsewhere, this can be done in `my.cnf' or on the MySQL server command line. Before the *Note `NDB': mysql-cluster. storage engine can be used, at least one MGM node must be operational, as well as any desired data nodes. *Note `NDB': mysql-cluster, the MySQL Cluster storage engine, is available in binary distributions for Linux, Mac OS X, Solaris. and Windows. We are working to support MySQL Cluster on all operating systems supported by the MySQL Server. For information about installing MySQL Cluster, see *Note mysql-cluster-installation::.  File: manual.info, Node: mysql-cluster-quick, Next: mysql-cluster-config-file, Prev: mysql-cluster-configuration, Up: mysql-cluster-configuration 17.3.1 Quick Test Setup of MySQL Cluster ---------------------------------------- To familiarize you with the basics, we will describe the simplest possible configuration for a functional MySQL Cluster. After this, you should be able to design your desired setup from the information provided in the other relevant sections of this chapter. First, you need to create a configuration directory such as `/var/lib/mysql-cluster', by executing the following command as the system `root' user: shell> mkdir /var/lib/mysql-cluster In this directory, create a file named `config.ini' that contains the following information. Substitute appropriate values for `HostName' and `DataDir' as necessary for your system. # file "config.ini" - showing minimal setup consisting of 1 data node, # 1 management server, and 3 MySQL servers. # The empty default sections are not required, and are shown only for # the sake of completeness. # Data nodes must provide a hostname but MySQL Servers are not required # to do so. # If you don't know the hostname for your machine, use localhost. # The DataDir parameter also has a default value, but it is recommended to # set it explicitly. # Note: [db], [api], and [mgm] are aliases for [ndbd], [mysqld], and [ndb_mgmd], # respectively. [db] is deprecated and should not be used in new installations. [ndbd default] NoOfReplicas= 1 [mysqld default] [ndb_mgmd default] [tcp default] [ndb_mgmd] HostName= myhost.example.com [ndbd] HostName= myhost.example.com DataDir= /var/lib/mysql-cluster [mysqld] [mysqld] [mysqld] You can now start the *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. management server. By default, it attempts to read the `config.ini' file in its current working directory, so change location into the directory where the file is located and then invoke *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd.: shell> cd /var/lib/mysql-cluster shell> ndb_mgmd Then start a single data node by running *Note `ndbd': mysql-cluster-programs-ndbd.: shell> ndbd For command-line options which can be used when starting *Note `ndbd': mysql-cluster-programs-ndbd, see *Note mysql-cluster-program-options-common::. By default, *Note `ndbd': mysql-cluster-programs-ndbd. looks for the management server at `localhost' on port 1186. *Note*: If you have installed MySQL from a binary tarball, you will need to specify the path of the *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. and *Note `ndbd': mysql-cluster-programs-ndbd. servers explicitly. (Normally, these will be found in `/usr/local/mysql/bin'.) Finally, change location to the MySQL data directory (usually `/var/lib/mysql' or `/usr/local/mysql/data'), and make sure that the `my.cnf' file contains the option necessary to enable the NDB storage engine: [mysqld] ndbcluster You can now start the MySQL server as usual: shell> mysqld_safe --user=mysql & Wait a moment to make sure the MySQL server is running properly. If you see the notice `mysql ended', check the server's `.err' file to find out what went wrong. If all has gone well so far, you now can start using the cluster. Connect to the server and verify that the *Note `NDBCLUSTER': mysql-cluster. storage engine is enabled: shell> mysql Welcome to the MySQL monitor. Commands end with ; or \g. Your MySQL connection id is 1 to server version: 5.1.59 Type 'help;' or '\h' for help. Type '\c' to clear the buffer. mysql> SHOW ENGINES\G ... *************************** 12. row *************************** Engine: NDBCLUSTER Support: YES Comment: Clustered, fault-tolerant, memory-based tables *************************** 13. row *************************** Engine: NDB Support: YES Comment: Alias for NDBCLUSTER ... The row numbers shown in the preceding example output may be different from those shown on your system, depending upon how your server is configured. Try to create an *Note `NDBCLUSTER': mysql-cluster. table: shell> mysql mysql> USE test; Database changed mysql> CREATE TABLE ctest (i INT) ENGINE=NDBCLUSTER; Query OK, 0 rows affected (0.09 sec) mysql> SHOW CREATE TABLE ctest \G *************************** 1. row *************************** Table: ctest Create Table: CREATE TABLE `ctest` ( `i` int(11) default NULL ) ENGINE=ndbcluster DEFAULT CHARSET=latin1 1 row in set (0.00 sec) To check that your nodes were set up properly, start the management client: shell> ndb_mgm Use the `SHOW' command from within the management client to obtain a report on the cluster's status: ndb_mgm> SHOW Cluster Configuration --------------------- [ndbd(NDB)] 1 node(s) id=2 @127.0.0.1 (Version: 3.5.3, Nodegroup: 0, Master) [ndb_mgmd(MGM)] 1 node(s) id=1 @127.0.0.1 (Version: 3.5.3) [mysqld(API)] 3 node(s) id=3 @127.0.0.1 (Version: 3.5.3) id=4 (not connected, accepting connect from any host) id=5 (not connected, accepting connect from any host) At this point, you have successfully set up a working MySQL Cluster. You can now store data in the cluster by using any table created with `ENGINE=NDBCLUSTER' or its alias `ENGINE=NDB'.  File: manual.info, Node: mysql-cluster-config-file, Next: mysql-cluster-params-overview, Prev: mysql-cluster-quick, Up: mysql-cluster-configuration 17.3.2 MySQL Cluster Configuration Files ---------------------------------------- * Menu: * mysql-cluster-config-example:: MySQL Cluster Configuration: Basic Example * mysql-cluster-config-starting:: Recommended Starting Configurations for MySQL Cluster NDB 6.2 and Later * mysql-cluster-connectstring:: The MySQL Cluster Connectstring * mysql-cluster-computer-definition:: Defining Computers in a MySQL Cluster * mysql-cluster-mgm-definition:: Defining a MySQL Cluster Management Server * mysql-cluster-ndbd-definition:: Defining MySQL Cluster Data Nodes * mysql-cluster-api-definition:: Defining SQL and Other API Nodes in a MySQL Cluster * mysql-cluster-tcp-definition:: MySQL Cluster TCP/IP Connections * mysql-cluster-tcp-definition-direct:: MySQL Cluster TCP/IP Connections Using Direct Connections * mysql-cluster-shm-definition:: MySQL Cluster Shared-Memory Connections * mysql-cluster-sci-definition:: SCI Transport Connections in MySQL Cluster * mysql-cluster-config-lcp-params:: Configuring MySQL Cluster Parameters for Local Checkpoints * mysql-cluster-config-send-buffers:: Configuring MySQL Cluster Send Buffer Parameters Configuring MySQL Cluster requires working with two files: * `my.cnf': Specifies options for all MySQL Cluster executables. This file, with which you should be familiar with from previous work with MySQL, must be accessible by each executable running in the cluster. * `config.ini': This file, sometimes known as the _global configuration file_, is read only by the MySQL Cluster management server, which then distributes the information contained therein to all processes participating in the cluster. `config.ini' contains a description of each node involved in the cluster. This includes configuration parameters for data nodes and configuration parameters for connections between all nodes in the cluster. For a quick reference to the sections that can appear in this file, and what sorts of configuration parameters may be placed in each section, see Sections of the `config.ini' File. Caching of configuration data Beginning with MySQL Cluster NDB 6.4.0, MySQL Cluster uses _stateful configuration_. The global configuration file is no longer read every time the management server is restarted. Instead, the management server caches the configuration the first time it is started, and thereafter, the global confiuration file is read only when one of the following items is true: * The management server is started using the `--initial' option In this case, the global configuration file is re-read, any existing cache files are deleted, and the management server creates a new configuration cache. * The management server is started using the `--reload' option In this case, the management server compares its cache with the global configuration file. If they differ, the management server creates a new configuration cache; any existing configuration cache is preserved, but not used. If the management server's cache and the global configuration file contain the same configuration data, then the existing cache is used, and no new cache is created. * The management server is started using a `--config-cache' option Beginning with MySQL Cluster NDB 7.0.15 and MySQL Cluster NDB 7.1.4, this option can be used to force the management server to bypass configuration caching altogether. In this case, the management server ignores any configuration files that may be present, always reading its configuration data from the `config.ini' file instead. * No configuration cache is found In this case, the management server reads the global configuration file and creates a cache containing the same configuration data as found in the file. Configuration cache files Beginning with MySQL Cluster 6.4.0, the management server by default creates configuration cache files in a directory named `mysql-cluster' in the MySQL installation directory. (If you build MySQL Cluster from source on a Unix system, the default location is `/usr/local/mysql-cluster'.) This can be overridden at run time by starting the management server with the `--configdir' option. Configuration cache files are binary files named according to the pattern `ndb_NODE_ID_config.bin.SEQ_ID', where NODE_ID is the management server's node ID in the cluster, and SEQ_ID is a cache idenitifer. Cache files are numbered sequentially using SEQ_ID, in the order in which they are created. The management server uses the latest cache file as determined by the SEQ_ID. *Note*: It is possible to roll back to a previous configuration by deleting later configuration cache files, or by renaming an earlier cache file so that it has a higher SEQ_ID. However, since configuration cache files are written in a binary format, you should not attempt to edit their contents by hand. For more information about the `--configdir', `--initial', and `--reload' options for the MySQL Cluster management server, see *Note mysql-cluster-programs-ndb-mgmd::. We are continuously making improvements in Cluster configuration and attempting to simplify this process. Although we strive to maintain backward compatibility, there may be times when introduce an incompatible change. In such cases we will try to let Cluster users know in advance if a change is not backward compatible. If you find such a change and we have not documented it, please report it in the MySQL bugs database using the instructions given in *Note bug-reports::.  File: manual.info, Node: mysql-cluster-config-example, Next: mysql-cluster-config-starting, Prev: mysql-cluster-config-file, Up: mysql-cluster-config-file 17.3.2.1 MySQL Cluster Configuration: Basic Example ................................................... To support MySQL Cluster, you will need to update `my.cnf' as shown in the following example. You may also specify these parameters on the command line when invoking the executables. *Note*: The options shown here should not be confused with those that are used in `config.ini' global configuration files. Global configuration options are discussed later in this section. # my.cnf # example additions to my.cnf for MySQL Cluster # (valid in MySQL 5.1) # enable ndbcluster storage engine, and provide connectstring for # management server host (default port is 1186) [mysqld] ndbcluster ndb-connectstring=ndb_mgmd.mysql.com # provide connectstring for management server host (default port: 1186) [ndbd] connect-string=ndb_mgmd.mysql.com # provide connectstring for management server host (default port: 1186) [ndb_mgm] connect-string=ndb_mgmd.mysql.com # provide location of cluster configuration file [ndb_mgmd] config-file=/etc/config.ini (For more information on connectstrings, see *Note mysql-cluster-connectstring::.) # my.cnf # example additions to my.cnf for MySQL Cluster # (will work on all versions) # enable ndbcluster storage engine, and provide connectstring for management # server host to the default port 1186 [mysqld] ndbcluster ndb-connectstring=ndb_mgmd.mysql.com:1186 *Important*: Once you have started a *Note `mysqld': mysqld. process with the *Note `NDBCLUSTER': mysql-cluster. and `ndb-connectstring' parameters in the `[mysqld]' in the `my.cnf' file as shown previously, you cannot execute any *Note `CREATE TABLE': create-table. or *Note `ALTER TABLE': alter-table. statements without having actually started the cluster. Otherwise, these statements will fail with an error. _This is by design_. You may also use a separate `[mysql_cluster]' section in the cluster `my.cnf' file for settings to be read and used by all executables: # cluster-specific settings [mysql_cluster] ndb-connectstring=ndb_mgmd.mysql.com:1186 For additional *Note `NDB': mysql-cluster. variables that can be set in the `my.cnf' file, see *Note mysql-cluster-system-variables::. The MySQL Cluster global configuration file is named `config.ini' by default. It is read by *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. at startup and can be placed anywhere. Its location and name are specified by using `--config-file=PATH_NAME' on the *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. command line. If the configuration file is not specified, *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. by default tries to read a file named `config.ini' located in the current working directory. The global configuration file for MySQL Cluster uses INI format, which consists of sections preceded by section headings (surrounded by square brackets), followed by the appropriate parameter names and values. One deviation from the standard INI format is that the parameter name and value can be separated by a colon (``:'') as well as the equal sign (``=''); however, the equal sign is preferred. Another deviation is that sections are not uniquely identified by section name. Instead, unique sections (such as two different nodes of the same type) are identified by a unique ID specified as a parameter within the section. Default values are defined for most parameters, and can also be specified in `config.ini'. (Prior to MySQL Cluster NDB 6.3.25 and MySQL Cluster NDB 7.0.6, there was no default value for `NoOfReplicas', which always had to be specified explicitly in the `[ndbd default]' section. Beginning with versions just stated, the default value is 2, which is the recommended setting in most common usage scenarios.) To create a default value section, simply add the word `default' to the section name. For example, an `[ndbd]' section contains parameters that apply to a particular data node, whereas an `[ndbd default]' section contains parameters that apply to all data nodes. Suppose that all data nodes should use the same data memory size. To configure them all, create an `[ndbd default]' section that contains a `DataMemory' line to specify the data memory size. The global configuration file must define the computers and nodes involved in the cluster and on which computers these nodes are located. An example of a simple configuration file for a cluster consisting of one management server, two data nodes and two MySQL servers is shown here: # file "config.ini" - 2 data nodes and 2 SQL nodes # This file is placed in the startup directory of ndb_mgmd (the # management server) # The first MySQL Server can be started from any host. The second # can be started only on the host mysqld_5.mysql.com [ndbd default] NoOfReplicas= 2 DataDir= /var/lib/mysql-cluster [ndb_mgmd] Hostname= ndb_mgmd.mysql.com DataDir= /var/lib/mysql-cluster [ndbd] HostName= ndbd_2.mysql.com [ndbd] HostName= ndbd_3.mysql.com [mysqld] [mysqld] HostName= mysqld_5.mysql.com *Note*: The preceding example is intended as a minimal starting configuration for purposes of familiarization with MySQL Cluster, and is almost certain not to be sufficient for production settings. See *Note mysql-cluster-config-starting::, which provides more complete example starting configurations for use with MySQL Cluster NDB 6.2 and newer versions of MySQL Cluster. Each node has its own section in the `config.ini' file. For example, this cluster has two data nodes, so the preceding configuration file contains two `[ndbd]' sections defining these nodes. *Note*: Do not place comments on the same line as a section heading in the `config.ini' file; this causes the management server not to start because it cannot parse the configuration file in such cases. * Sections of the `config.ini' File * There are six different sections that you can use in the `config.ini' configuration file, as described in the following list: * `[computer]': Defines cluster hosts. This is not required to configure a viable MySQL Cluster, but be may used as a convenience when setting up a large cluster. See *Note mysql-cluster-computer-definition::, for more information. * `[ndbd]': Defines a cluster data node (*Note `ndbd': mysql-cluster-programs-ndbd. process). See *Note mysql-cluster-ndbd-definition::, for details. * `[mysqld]': Defines the cluster's MySQL server nodes (also called SQL or API nodes). For a discussion of SQL node configuration, see *Note mysql-cluster-api-definition::. * `[mgm]' or `[ndb_mgmd]': Defines a cluster management server (MGM) node. For information concerning the configuration of MGM nodes, see *Note mysql-cluster-mgm-definition::. * `[tcp]': Defines a TCP/IP connection between cluster nodes, with TCP/IP being the default connection protocol. Normally, `[tcp]' or `[tcp default]' sections are not required to set up a MySQL Cluster, as the cluster handles this automatically; however, it may be necessary in some situations to override the defaults provided by the cluster. See *Note mysql-cluster-tcp-definition::, for information about available TCP/IP configuration parameters and how to use them. (You may also find *Note mysql-cluster-tcp-definition-direct:: to be of interest in some cases.) * `[shm]': Defines shared-memory connections between nodes. In MySQL 5.1, it is enabled by default, but should still be considered experimental. For a discussion of SHM interconnects, see *Note mysql-cluster-shm-definition::. * `[sci]':Defines _Scalable Coherent Interface_ connections between cluster data nodes. Such connections require software which, while freely available, is not part of the MySQL Cluster distribution, as well as specialized hardware. See *Note mysql-cluster-sci-definition:: for detailed information about SCI interconnects. You can define `default' values for each section. All Cluster parameter names are case-insensitive, which differs from parameters specified in `my.cnf' or `my.ini' files.  File: manual.info, Node: mysql-cluster-config-starting, Next: mysql-cluster-connectstring, Prev: mysql-cluster-config-example, Up: mysql-cluster-config-file 17.3.2.2 Recommended Starting Configurations for MySQL Cluster NDB 6.2 and Later ................................................................................ Achieving the best performance from a MySQL Cluster depends on a number of factors including the following: * MySQL Cluster software version * Numbers of data nodes and SQL nodes * Hardware * Operating system * Amount of data to be stored * Size and type of load under which the cluster is to operate Therefore, obtaining an optimum configuration is likely to be an iterative process, the outcome of which can vary widely with the specifics of each MySQL Cluster deployment. Changes in configuration are also likely to be indicated when changes are made in the platform on which the cluster is run, or in applications that use the MySQL Cluster's data. For these reasons, it is not possible to offer a single configuration that is ideal for all usage scenarios. However, in this section, we provide recommended base configurations for MySQL Cluster NDB 6.2 and 6.3 that can serve as reasonable starting points. Starting configuration for MySQL Cluster NDB 6.2 The following is a recommended starting point for configuring a cluster running MySQL Cluster NDB 6.2. # TCP PARAMETERS [tcp default] SendBufferMemory=2M ReceiveBufferMemory=2M # Increasing the sizes of these 2 buffers beyond the default values # helps prevent bottlenecks due to slow disk I/O. # MANAGEMENT NODE PARAMETERS [ndb_mgmd default] DataDir=PATH/TO/MANAGEMENT/SERVER/DATA/DIRECTORY # It is possible to use a different data directory for each management # server, but for ease of administration it is preferable to be # consistent. [ndb_mgmd] HostName=MANAGEMENT-SERVER-1-HOSTNAME # NodeId=MANAGEMENT-SERVER-1-NODEID [ndb_mgmd] HostName=MANAGEMENT-SERVER-2-HOSTNAME # Using 2 management servers helps guarantee that there is always an # arbitrator in the event of network partitioning, and so is # recommended for high availability. Each management server must be # identified by a HostName. You may for the sake of convenience specify # a node ID for any management server, although one will be allocated # for it automatically; if you do so, it must be in the range 1-255 # inclusive and must be unique among all IDs specified for cluster # nodes. # DATA NODE PARAMETERS [ndbd default] NoOfReplicas=2 # Using 2 replicas is recommended to guarantee availability of data; # using only 1 replica does not provide any redundancy, which means # that the failure of a single data node causes the entire cluster to # shut down. We do not recommend using more than 2 replicas, since 2 is # sufficient to provide high availability, and we do not currently test # with greater values for this parameter. LockPagesInMainMemory=1 # On Linux and Solaris systems, setting this parameter locks data node # processes into memory. Doing so prevents them from swapping to disk, # which can severely degrade cluster performance. DataMemory=3072M IndexMemory=384M # The values provided for DataMemory and IndexMemory assume 4 GB RAM # per data node. However, for best results, you should first calculate # the memory that would be used based on the data you actually plan to # store (you may find the *Note ndb_size.pl: mysql-cluster-programs-ndb-size-pl. utility helpful in estimating # this), then allow an extra 20% over the calculated values. Naturally, # you should ensure that each data node host has at least as much # physical memory as the sum of these two values. # ODirect=1 # Enabling this parameter causes NDBCLUSTER to try using O_DIRECT # writes for local checkpoints and redo logs; this can reduce load on # CPUs. We recommend doing so when using MySQL Cluster NDB 6.2.3 or # newer on systems running Linux kernel 2.6 or later. NoOfFragmentLogFiles=300 DataDir=PATH/TO/DATA/NODE/DATA/DIRECTORY MaxNoOfConcurrentOperations=100000 TimeBetweenGlobalCheckpoints=1000 TimeBetweenEpochs=200 DiskCheckpointSpeed=10M DiskCheckpointSpeedInRestart=100M RedoBuffer=32M # MaxNoOfLocalScans=64 MaxNoOfTables=1024 MaxNofOfOrderedIndexes=256 [ndbd] HostName=DATA-NODE-A-HOSTNAME # NodeId=DATA-NODE-A-NODEID [ndbd] HostName=DATA-NODE-B-HOSTNAME # NodeId=DATA-NODE-B-NODEID # You must have an [ndbd] section for every data node in the cluster; # each of these sections must include a HostName. Each section may # optionally include an Id for convenience, but in most cases, it is # sufficient to allow the cluster to allocate node IDs dynamically. If # you do specify the node ID for a data node, it must be in the range 1 # to 48 inclusive and must be unique among all IDs specified for # cluster nodes. # SQL NODE / API NODE PARAMETERS [mysqld] # HostName=SQL-NODE-1-HOSTNAME # NodeId=SQL-NODE-A-NODEID [mysqld] [mysqld] # Each API or SQL node that connects to the cluster requires a [mysqld] # or [api] section of its own. Each such section defines a connection # `slot'; you should have at least as many of these sections in the # config.ini file as the total number of API nodes and SQL nodes that # you wish to have connected to the cluster at any given time. There is # no performance or other penalty for having extra slots available in # case you find later that you want or need more API or SQL nodes to # connect to the cluster at the same time. # If no HostName is specified for a given [mysqld] or [api] section, # then _any_ API or SQL node may use that slot to connect to the # cluster. You may wish to use an explicit HostName for one connection slot # to guarantee that an API or SQL node from that host can always # connect to the cluster. If you wish to prevent API or SQL nodes from # connecting from other than a desired host or hosts, then use a # HostName for every [mysqld] or [api] section in the config.ini file. # You can if you wish define a node ID (Id parameter) for any API or # SQL node, but this is not necessary; if you do so, it must be in the # range 1 to 255 inclusive and must be unique among all IDs specified # for cluster nodes. Starting configuration for MySQL Cluster NDB 6.3 The following is a recommended starting point for configuring a cluster running MySQL Cluster NDB 6.3. It is similar to the recommendation for MySQL Cluster NDB 6.2, with the addition of parameters for better control of *Note `NDBCLUSTER': mysql-cluster. process threads. # TCP PARAMETERS [tcp default] SendBufferMemory=2M ReceiveBufferMemory=2M # Increasing the sizes of these 2 buffers beyond the default values # helps prevent bottlenecks due to slow disk I/O. # MANAGEMENT NODE PARAMETERS [ndb_mgmd default] DataDir=PATH/TO/MANAGEMENT/SERVER/DATA/DIRECTORY # It is possible to use a different data directory for each management # server, but for ease of administration it is preferable to be # consistent. [ndb_mgmd] HostName=MANAGEMENT-SERVER-A-HOSTNAME # NodeId=MANAGEMENT-SERVER-A-NODEID [ndb_mgmd] HostName=MANAGEMENT-SERVER-B-HOSTNAME # NodeId=MANAGEMENT-SERVER-B-NODEID # Using 2 management servers helps guarantee that there is always an # arbitrator in the event of network partitioning, and so is # recommended for high availability. Each management server must be # identified by a HostName. You may for the sake of convenience specify # a NodeId for any management server, although one will be allocated # for it automatically; if you do so, it must be in the range 1-255 # inclusive and must be unique among all IDs specified for cluster # nodes. # DATA NODE PARAMETERS [ndbd default] NoOfReplicas=2 # Using 2 replicas is recommended to guarantee availability of data; # using only 1 replica does not provide any redundancy, which means # that the failure of a single data node causes the entire cluster to # shut down. We do not recommend using more than 2 replicas, since 2 is # sufficient to provide high availability, and we do not currently test # with greater values for this parameter. LockPagesInMainMemory=1 # On Linux and Solaris systems, setting this parameter locks data node # processes into memory. Doing so prevents them from swapping to disk, # which can severely degrade cluster performance. DataMemory=3072M IndexMemory=384M # The values provided for DataMemory and IndexMemory assume 4 GB RAM # per data node. However, for best results, you should first calculate # the memory that would be used based on the data you actually plan to # store (you may find the *Note ndb_size.pl: mysql-cluster-programs-ndb-size-pl. utility helpful in estimating # this), then allow an extra 20% over the calculated values. Naturally, # you should ensure that each data node host has at least as much # physical memory as the sum of these two values. # ODirect=1 # Enabling this parameter causes NDBCLUSTER to try using O_DIRECT # writes for local checkpoints and redo logs; this can reduce load on # CPUs. We recommend doing so when using MySQL Cluster NDB 6.2.3 or # newer on systems running Linux kernel 2.6 or later. NoOfFragmentLogFiles=300 DataDir=PATH/TO/DATA/NODE/DATA/DIRECTORY MaxNoOfConcurrentOperations=100000 SchedulerSpinTimer=400 SchedulerExecutionTimer=100 RealTimeScheduler=1 # Setting these parameters allows you to take advantage of real-time scheduling # of NDBCLUSTER threads (introduced in MySQL Cluster NDB 6.3.4) to get higher # throughput. TimeBetweenGlobalCheckpoints=1000 TimeBetweenEpochs=200 DiskCheckpointSpeed=10M DiskCheckpointSpeedInRestart=100M RedoBuffer=32M # CompressedLCP=1 # CompressedBackup=1 # Enabling CompressedLCP and CompressedBackup causes, respectively, local checkpoint files and backup files to be compressed, which can result in a space savings of up to 50% over noncompressed LCPs and backups. # MaxNoOfLocalScans=64 MaxNoOfTables=1024 MaxNofOfOrderedIndexes=256 [ndbd] HostName=DATA-NODE-A-HOSTNAME # NodeId=DATA-NODE-A-NODEID LockExecuteThreadToCPU=1 LockMaintThreadsToCPU=0 # On systems with multiple CPUs, these parameters can be used to lock NDBCLUSTER # threads to specific CPUs [ndbd] HostName=DATA-NODE-B-HOSTNAME # NodeId=DATA-NODE-B-NODEID LockExecuteThreadToCPU=1 LockMaintThreadsToCPU=0 # You must have an [ndbd] section for every data node in the cluster; # each of these sections must include a HostName. Each section may # optionally include a NodeId for convenience, but in most cases, it is # sufficient to allow the cluster to allocate node IDs dynamically. If # you do specify the node ID for a data node, it must be in the range 1 # to 48 inclusive and must be unique among all IDs specified for # cluster nodes. # SQL NODE / API NODE PARAMETERS [mysqld] # HostName=SQL-NODE-A-HOSTNAME # NodeId=SQL-NODE-A-NODEID [mysqld] [mysqld] # Each API or SQL node that connects to the cluster requires a [mysqld] # or [api] section of its own. Each such section defines a connection # `slot'; you should have at least as many of these sections in the # config.ini file as the total number of API nodes and SQL nodes that # you wish to have connected to the cluster at any given time. There is # no performance or other penalty for having extra slots available in # case you find later that you want or need more API or SQL nodes to # connect to the cluster at the same time. # If no HostName is specified for a given [mysqld] or [api] section, # then _any_ API or SQL node may use that slot to connect to the # cluster. You may wish to use an explicit HostName for one connection slot # to guarantee that an API or SQL node from that host can always # connect to the cluster. If you wish to prevent API or SQL nodes from # connecting from other than a desired host or hosts, then use a # HostName for every [mysqld] or [api] section in the config.ini file. # You can if you wish define a node ID (NodeId parameter) for any API or # SQL node, but this is not necessary; if you do so, it must be in the # range 1 to 255 inclusive and must be unique among all IDs specified # for cluster nodes. Recommended `my.cnf' options for SQL nodes MySQL Servers acting as MySQL Cluster SQL nodes must always be started with the `--ndbcluster' and `--ndb-connectstring' options, either on the command line or in `my.cnf'. In addition, set the following options for all *Note `mysqld': mysqld. processes in the cluster, unless your setup requires otherwise: * `--ndb-use-exact-count=0' * `--ndb-index-stat-enable=0' * `--ndb-force-send=1' * `--engine-condition-pushdown=1'  File: manual.info, Node: mysql-cluster-connectstring, Next: mysql-cluster-computer-definition, Prev: mysql-cluster-config-starting, Up: mysql-cluster-config-file 17.3.2.3 The MySQL Cluster Connectstring ........................................ With the exception of the MySQL Cluster management server (*Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd.), each node that is part of a MySQL Cluster requires a _connectstring_ that points to the management server's location. This connectstring is used in establishing a connection to the management server as well as in performing other tasks depending on the node's role in the cluster. The syntax for a connectstring is as follows: [nodeid=NODE_ID, ]HOST-DEFINITION[, HOST-DEFINITION[, ...]] HOST-DEFINITION: HOST_NAME[:PORT_NUMBER] `node_id' is an integer larger than 1 which identifies a node in `config.ini'. HOST_NAME is a string representing a valid Internet host name or IP address. PORT_NUMBER is an integer referring to a TCP/IP port number. example 1 (long): "nodeid=2,myhost1:1100,myhost2:1100,192.168.0.3:1200" example 2 (short): "myhost1" `localhost:1186' is used as the default connectstring value if none is provided. If PORT_NUM is omitted from the connectstring, the default port is 1186. This port should always be available on the network because it has been assigned by IANA for this purpose (see `http://www.iana.org/assignments/port-numbers' for details). By listing multiple host definitions, it is possible to designate several redundant management servers. A MySQL Cluster data or API node attempts to contact successive management servers on each host in the order specified, until a successful connection has been established. Beginning with MySQL Cluster NDB 6.3.19, it is also possible in a connectstring to specify one or more bind addresses to be used by nodes having multiple network interfaces for connecting to management servers. A bind address consists of a hostname or network address and an optional port number. This enhanced syntax for connectstrings is shown here: [nodeid=NODE_ID, ] [bind-address=HOST-DEFINITION, ] HOST-DEFINITION[; bind-address=HOST-DEFINITION] HOST-DEFINITION[; bind-address=HOST-DEFINITION] [, ...]] HOST-DEFINITION: HOST_NAME[:PORT_NUMBER] If a single bind address is used in the connectstring _prior_ to specifying any management hosts, then this address is used as the default for connecting to any of them (unless overridden for a given management server; see later in this section for an example). For example, the following connectstring causes the node to use `192.168.178.242' regardless of the management server to which it connects: bind-address=192.168.178.242, poseidon:1186, perch:1186 If a bind address is specified _following_ a management host definition, then it is used only for connecting to that management node. Consider the following connectstring: poseidon:1186;bind-address=localhost, perch:1186;bind-address=192.168.178.242 In this case, the node uses `localhost' to connect to the management server running on the host named `poseidon' and `192.168.178.242' to connect to the management server running on the host named `perch'. You can specify a default bind address and then override this default for one or more specific management hosts. In the following example, `localhost' is used for connecting to the management server running on host `poseidon'; since `192.168.178.242' is specified first (before any management server definitions), it is the default bind address and so is used for connecting to the management servers on hosts `perch' and `orca': bind-address=192.168.178.242,poseidon:1186;bind-address=localhost,perch:1186,orca:2200 There are a number of different ways to specify the connectstring: * Each executable has its own command-line option which enables specifying the management server at startup. (See the documentation for the respective executable.) * It is also possible to set the connectstring for all nodes in the cluster at once by placing it in a `[mysql_cluster]' section in the management server's `my.cnf' file. * For backward compatibility, two other options are available, using the same syntax: 1. Set the `NDB_CONNECTSTRING' environment variable to contain the connectstring. 2. Write the connectstring for each executable into a text file named `Ndb.cfg' and place this file in the executable's startup directory. However, these are now deprecated and should not be used for new installations. The recommended method for specifying the connectstring is to set it on the command line or in the `my.cnf' file for each executable. Previous to MySQL Cluster NDB 7.0.15 and MySQL Cluster NDB 7.1.4, the maximum length of a connectstring was 1024 characters.  File: manual.info, Node: mysql-cluster-computer-definition, Next: mysql-cluster-mgm-definition, Prev: mysql-cluster-connectstring, Up: mysql-cluster-config-file 17.3.2.4 Defining Computers in a MySQL Cluster .............................................. The `[computer]' section has no real significance other than serving as a way to avoid the need of defining host names for each node in the system. All parameters mentioned here are required. * `Id' Options for id-computer *Restart Type* initial, node *Permitted Values * *Type* `string' *Default* `' *Range* `-' This is a unique identifier, used to refer to the host computer elsewhere in the configuration file. *Important*: The computer ID is _not_ the same as the node ID used for a management, API, or data node. Unlike the case with node IDs, you cannot use `NodeId' in place of `Id' in the `[computer]' section of the `config.ini' file. * `HostName' Options for hostname-computer *Restart Type* system *Permitted Values * *Type* `string' *Default* `' *Range* `-' This is the computer's hostname or IP address.  File: manual.info, Node: mysql-cluster-mgm-definition, Next: mysql-cluster-ndbd-definition, Prev: mysql-cluster-computer-definition, Up: mysql-cluster-config-file 17.3.2.5 Defining a MySQL Cluster Management Server ................................................... The `[ndb_mgmd]' section is used to configure the behavior of the management server. `[mgm]' can be used as an alias; the two section names are equivalent. All parameters in the following list are optional and assume their default values if omitted. *Note*: If neither the `ExecuteOnComputer' nor the `HostName' parameter is present, the default value `localhost' will be assumed for both. * `Id' Options for id-mgmd *Version Deprecated* 5.1.51-ndb-7.1.9 *Deprecated* 5.1.51-ndb-7.1.9 *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `' *Range* `1-63' Each node in the cluster has a unique identity. For a management node, this is represented by an integer value in the range 1 to 63 inclusive (previous to MySQL Cluster NDB 6.1.1), or in the range 1 to 255 inclusive (MySQL Cluster NDB 6.1.1 and later). This ID is used by all internal cluster messages for addressing the node, and so must be unique for each MySQL Cluster node, regardless of the type of node. *Note*: Data node IDs must be less than 49, regardless of the MySQL Cluster version used. If you plan to deploy a large number of data nodes, it is a good idea to limit the node IDs for management nodes (and API nodes) to values greater than 48. The use of the `Id' parameter for identifying management nodes is deprecated in favor of `NodeId' beginning with MySQL Cluster NDB 6.2.19, MySQL Cluster NDB 6.3.39, MySQL Cluster NDB 7.0.20, and MySQL Cluster NDB 7.1.9. Although `Id' continues to be supported for backward compatibility, it now generates a warning. * `NodeId' Options for nodeid-mgmd *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `' *Range* `1-63' Each node in the cluster has a unique identity. For a management node, this is represented by an integer value in the range 1 to 63 inclusive (previous to MySQL Cluster NDB 6.1.1), or in the range 1 to 255 inclusive (MySQL Cluster NDB 6.1.1 and later). This ID is used by all internal cluster messages for addressing the node, and so must be unique for each MySQL Cluster node, regardless of the type of node. *Note*: Data node IDs must be less than 49, regardless of the MySQL Cluster version used. If you plan to deploy a large number of data nodes, it is a good idea to limit the node IDs for management nodes (and API nodes) to values greater than 48. `NodeId' is the preferred parameter name to use when identifying management nodes beginning with MySQL Cluster NDB 6.2.19, MySQL Cluster NDB 6.3.39, MySQL Cluster NDB 7.0.20, and MySQL Cluster NDB 7.1.9. Although `Id' continues to be supported for backward compatibility, it is now deprecated and generates a warning when used. * `ExecuteOnComputer' Options for executeoncomputer-mgmd *Restart Type* system *Permitted Values * *Type* `string' *Default* `' *Range* `-' This refers to the `Id' set for one of the computers defined in a `[computer]' section of the `config.ini' file. * `PortNumber' Options for portnumber-mgmd *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `1186' *Range* `0-64K' This is the port number on which the management server listens for configuration requests and management commands. * `HostName' Options for hostname-mgmd *Restart Type* system *Permitted Values * *Type* `string' *Default* `' *Range* `-' Specifying this parameter defines the hostname of the computer on which the management node is to reside. To specify a hostname other than `localhost', either this parameter or `ExecuteOnComputer' is required. * `LogDestination' Options for logdestination-mgmd *Restart Type* node *Permitted Values * *Type* `string' *Default* `FILE:filename=ndb_nodeid_cluster.log,maxsize=1000000,maxfiles=6' *Range* `-' This parameter specifies where to send cluster logging information. There are three options in this regard--`CONSOLE', `SYSLOG', and `FILE'--with `FILE' being the default: * `CONSOLE' outputs the log to `stdout': CONSOLE * `SYSLOG' sends the log to a `syslog' facility, possible values being one of `auth', `authpriv', `cron', `daemon', `ftp', `kern', `lpr', `mail', `news', `syslog', `user', `uucp', `local0', `local1', `local2', `local3', `local4', `local5', `local6', or `local7'. *Note*: Not every facility is necessarily supported by every operating system. SYSLOG:facility=syslog * `FILE' pipes the cluster log output to a regular file on the same machine. The following values can be specified: * `filename': The name of the log file. * `maxsize': The maximum size (in bytes) to which the file can grow before logging rolls over to a new file. When this occurs, the old log file is renamed by appending .N to the file name, where N is the next number not yet used with this name. * `maxfiles': The maximum number of log files. FILE:filename=cluster.log,maxsize=1000000,maxfiles=6 The default value for the `FILE' parameter is `FILE:filename=ndb_NODE_ID_cluster.log,maxsize=1000000,maxfiles=6', where NODE_ID is the ID of the node. It is possible to specify multiple log destinations separated by semicolons as shown here: CONSOLE;SYSLOG:facility=local0;FILE:filename=/var/log/mgmd * `ArbitrationRank' Options for arbitrationrank-mgmd *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `1' *Range* `0-2' This parameter is used to define which nodes can act as arbitrators. Only management nodes and SQL nodes can be arbitrators. `ArbitrationRank' can take one of the following values: * `0': The node will never be used as an arbitrator. * `1': The node has high priority; that is, it will be preferred as an arbitrator over low-priority nodes. * `2': Indicates a low-priority node which be used as an arbitrator only if a node with a higher priority is not available for that purpose. Normally, the management server should be configured as an arbitrator by setting its `ArbitrationRank' to 1 (the default for management nodes) and those for all SQL nodes to 0 (the default for SQL nodes). Beginning with MySQL 5.1.16 and MySQL Cluster NDB 6.1.3, it is possible to disable arbitration completely by setting `ArbitrationRank' to 0 on all management and SQL nodes. In MySQL Cluster NDB 7.0.7 and later releases, you can also control arbitration by overriding this parameter; to do this, set the `Arbitration' parameter in the `[ndbd default]' section of the `config.ini' global configuration file. * `ArbitrationDelay' Options for arbitrationdelay-mgmd *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `0' *Range* `0-4G' An integer value which causes the management server's responses to arbitration requests to be delayed by that number of milliseconds. By default, this value is 0; it is normally not necessary to change it. * `DataDir' Options for datadir-mgmd *Restart Type* node *Permitted Values * *Type* `string' *Default* `.' *Range* `-' This specifies the directory where output files from the management server will be placed. These files include cluster log files, process output files, and the daemon's process ID (PID) file. (For log files, this location can be overridden by setting the `FILE' parameter for `LogDestination' as discussed previously in this section.) The default value for this parameter is the directory in which *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. is located. * `HeartbeatThreadPriority' Beginning with MySQL Cluster NDB 6.3.32, MySQL Cluster NDB 7.0.13, and MySQL Cluster NDB 7.1.2, it is possible to use this parameter to set the scheduling policy and priority of heartbeat threads for management and API nodes. The syntax for setting this parameter is shown here: HeartbeatThreadPriority = POLICY[, PRIORITY] POLICY: {FIFO | RR} When setting this parameter, you must specify a policy. This is one of `FIFO' (first in, first out) or `RR' (round robin). The policy value is followed optionally by the priority (an integer). * `TotalSendBufferMemory' This parameter is available beginning with MySQL Cluster NDB 6.4.0. It is used to determine the total amount of memory to allocate on this node for shared send buffer memory among all configured transporters. If this parameter is set, its minimum permitted value is 256KB; the maxmimum is 4294967039. For more detailed information about the behavior and use of `TotalSendBufferMemory' and configuring send buffer memory parameters in MySQL Cluster NDB 6.4.0 and later, see *Note mysql-cluster-config-send-buffers::. *Note*: After making changes in a management node's configuration, it is necessary to perform a rolling restart of the cluster for the new configuration to take effect. To add new management servers to a running MySQL Cluster, it is also necessary to perform a rolling restart of all cluster nodes after modifying any existing `config.ini' files. For more information about issues arising when using multiple management nodes, see *Note mysql-cluster-limitations-multiple-nodes::.  File: manual.info, Node: mysql-cluster-ndbd-definition, Next: mysql-cluster-api-definition, Prev: mysql-cluster-mgm-definition, Up: mysql-cluster-config-file 17.3.2.6 Defining MySQL Cluster Data Nodes .......................................... The `[ndbd]' and `[ndbd default]' sections are used to configure the behavior of the cluster's data nodes. `[ndbd]' and `[ndbd default]' are always used as the section names whether you are using *Note `ndbd': mysql-cluster-programs-ndbd. or (in MySQL Cluster NDB 6.4.0 and later) *Note `ndbmtd': mysql-cluster-programs-ndbmtd. binaries for the data node processes. There are many parameters which control buffer sizes, pool sizes, timeouts, and so forth. The only mandatory parameters are: * Either `ExecuteOnComputer' or `HostName', which must be defined in the local `[ndbd]' section. * The parameter `NoOfReplicas', which must be defined in the `[ndbd default]' section, as it is common to all Cluster data nodes. *Note*: It is no longer strictly necessary to set `NoOfReplicas' starting with MySQL Cluster NDB 6.3.25 and MySQL Cluster NDB 7.0.6, where it acquires a default value (2). However, it remains good practice to set it explicitly. Most data node parameters are set in the `[ndbd default]' section. Only those parameters explicitly stated as being able to set local values are permitted to be changed in the `[ndbd]' section. Where present, `HostName', `NodeId' and `ExecuteOnComputer' _must_ be defined in the local `[ndbd]' section, and not in any other section of `config.ini'. In other words, settings for these parameters are specific to one data node. For those parameters affecting memory usage or buffer sizes, it is possible to use `K', `M', or `G' as a suffix to indicate units of 1024, 1024x1024, or 1024x1024x1024. (For example, `100K' means 100 x 1024 = 102400.) Parameter names and values are currently case-sensitive. Information about configuration parameters specific to MySQL Cluster Disk Data tables can be found later in this section. Beginning with MySQL Cluster NDB 6.4.0, all of these parameters also apply to *Note `ndbmtd': mysql-cluster-programs-ndbmtd. (the multi-threaded version of *Note `ndbd': mysql-cluster-programs-ndbd.). An additional data node configuration parameter `MaxNoOfExecutionThreads' applies to *Note `ndbmtd': mysql-cluster-programs-ndbmtd. only, and has no effect when used with *Note `ndbd': mysql-cluster-programs-ndbd. For more information, see *Note mysql-cluster-programs-ndbmtd::. Identifying data nodes The `NodeId' or `Id' value (that is, the data node identifier) can be allocated on the command line when the node is started or in the configuration file. * `Id' Options for id-ndbd *Version Deprecated* 5.1.51-ndb-7.1.9 *Deprecated* 5.1.51-ndb-7.1.9 *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `' *Range* `1-48' A unique node ID is used as the node's address for all cluster internal messages. For data nodes, this is an integer in the range 1 to 48 inclusive. Each node in the cluster must have a unique identifier. `NodeId' is the preferred parameter name to use when identifying data nodes beginning with MySQL Cluster NDB 6.2.19, MySQL Cluster NDB 6.3.39, MySQL Cluster NDB 7.0.20, and MySQL Cluster NDB 7.1.9. Although `Id' continues to be supported for backward compatibility, it is now deprecated and generates a warning when used. * `NodeId' Options for nodeid-ndbd *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `' *Range* `1-48' A unique node ID is used as the node's address for all cluster internal messages. For data nodes, this is an integer in the range 1 to 48 inclusive. Each node in the cluster must have a unique identifier. `NodeId' is the preferred parameter name to use when identifying data nodes beginning with MySQL Cluster NDB 6.2.19, MySQL Cluster NDB 6.3.39, MySQL Cluster NDB 7.0.20, and MySQL Cluster NDB 7.1.9. Although `Id' continues to be supported for backward compatibility, it is now deprecated and generates a warning when used. * `ExecuteOnComputer' Options for executeoncomputer-ndbd *Restart Type* system *Permitted Values * *Type* `string' *Default* `' *Range* `-' This refers to the `Id' set for one of the computers defined in a `[computer]' section. * `HostName' Options for hostname-ndbd *Restart Type* system *Permitted Values * *Type* `string' *Default* `localhost' *Range* `-' Specifying this parameter defines the hostname of the computer on which the data node is to reside. To specify a hostname other than `localhost', either this parameter or `ExecuteOnComputer' is required. * `ServerPort' Options for serverport-ndbd *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `' *Range* `1-64K' Each node in the cluster uses a port to connect to other nodes. By default, this port is allocated dynamically in such a way as to ensure that no two nodes on the same host computer receive the same port number, so it should normally not be necessary to specify a value for this parameter. However, if you need to be able to open specific ports in a firewall to permit communication between data nodes and API nodes (including SQL nodes), you can set this parameter to the number of the desired port in an `[ndbd]' section or (if you need to do this for multiple data nodes) the `[ndbd default]' section of the `config.ini' file, and then open the port having that number for incoming connections from SQL nodes, API nodes, or both. *Note*: Connections from data nodes to management nodes is done using the *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. management port (the management server's `PortNumber'; see *Note mysql-cluster-mgm-definition::) so outgoing connections to that port from any data nodes should always be permitted. * `TcpBind_INADDR_ANY' Setting this parameter to `TRUE' or `1' binds `IP_ADDR_ANY' so that connections can be made from anywhere (for autogenerated connections). The default is `FALSE' (`0'). This parameter was added in MySQL Cluster NDB 6.2.0. * `NodeGroup' Options for nodegroup-ndbd *Version Introduced* 5.1.30-ndb-6.4.0 *Restart Type* initial, system *Permitted Values * *Type* `numeric' *Default* `' *Range* `0-65536' This parameter can be used to assign a data node to a specific node group. It is read only when the cluster is started for the first time, and cannot be used to reassign a data node to a different node group online. It is generally not desirable to use this parameter in the `[ndbd default]' section of the `config.ini' file, and care must be taken not to assign nodes to node groups in such a way that an invalid numbers of nodes are assigned to any node groups. The `NodeGroup' parameter is chiefly intended for use in adding a new node group to a running MySQL Cluster without having to perform a rolling restart. For this purpose, you should set it to 65536 (the maximum value). You are not required to set a `NodeGroup' value for all cluster data nodes, only for those nodes which are to be started and added to the cluster as a new node group at a later time. For more information, see *Note mysql-cluster-online-add-node-example::. This parameter was added in MySQL Cluster NDB 6.4.0. * `NoOfReplicas' Options for noofreplicas-ndbd *Restart Type* initial, system *Permitted Values * *Type* `numeric' *Default* `None' *Range* `1-4' *Permitted Values * *Type* `numeric' *Default* `None' *Range* `1-4' *Permitted Values * *Type* `numeric' *Default* `2' *Range* `1-4' *Permitted Values * *Type* `numeric' *Default* `2' *Range* `1-4' This global parameter can be set only in the `[ndbd default]' section, and defines the number of replicas for each table stored in the cluster. This parameter also specifies the size of node groups. A node group is a set of nodes all storing the same information. Node groups are formed implicitly. The first node group is formed by the set of data nodes with the lowest node IDs, the next node group by the set of the next lowest node identities, and so on. By way of example, assume that we have 4 data nodes and that `NoOfReplicas' is set to 2. The four data nodes have node IDs 2, 3, 4 and 5. Then the first node group is formed from nodes 2 and 3, and the second node group by nodes 4 and 5. It is important to configure the cluster in such a manner that nodes in the same node groups are not placed on the same computer because a single hardware failure would cause the entire cluster to fail. If no node IDs are provided, the order of the data nodes will be the determining factor for the node group. Whether or not explicit assignments are made, they can be viewed in the output of the management client's `SHOW' command. Prior to MySQL Cluster NDB 6.3.25 and MySQL Cluster NDB 7.0.6, there was no default value for `NoOfReplicas'; beginning with these versions, the default value is 2, which is the recommended setting in most common usage scenarios. (Bug#44746) The maximum possible value is 4; _currently, only the values 1 and 2 are actually supported_. *Important*: Setting `NoOfReplicas' to 1 means that there is only a single copy of all Cluster data; in this case, the loss of a single data node causes the cluster to fail because there are no additional copies of the data stored by that node. The value for this parameter must divide evenly into the number of data nodes in the cluster. For example, if there are two data nodes, then `NoOfReplicas' must be equal to either 1 or 2, since 2/3 and 2/4 both yield fractional values; if there are four data nodes, then `NoOfReplicas' must be equal to 1, 2, or 4. * `DataDir' Options for datadir-ndbd *Restart Type* initial, node *Permitted Values * *Type* `string' *Default* `.' *Range* `-' This parameter specifies the directory where trace files, log files, pid files and error logs are placed. The default is the data node process working directory. * `FileSystemPath' Options for filesystempath-ndbd *Version Introduced* 5.1.15-ndb-6.1.1 *Restart Type* initial, node *Permitted Values * *Type* `string' *Default* `DataDir' *Range* `-' This parameter specifies the directory where all files created for metadata, REDO logs, UNDO logs (for Disk Data tables), and data files are placed. The default is the directory specified by `DataDir'. *Note*: This directory must exist before the *Note `ndbd': mysql-cluster-programs-ndbd. process is initiated. The recommended directory hierarchy for MySQL Cluster includes `/var/lib/mysql-cluster', under which a directory for the node's file system is created. The name of this subdirectory contains the node ID. For example, if the node ID is 2, this subdirectory is named `ndb_2_fs'. * `BackupDataDir' Options for backupdatadir-ndbd *Restart Type* initial, node *Permitted Values * *Type* `string' *Default* `FileSystemPath' *Range* `-' This parameter specifies the directory in which backups are placed. *Important*: The string '`/BACKUP'' is always appended to this value. For example, if you set the value of `BackupDataDir' to `/var/lib/cluster-data', then all backups are stored under `/var/lib/cluster-data/BACKUP'. This also means that the _effective_ default backup location is the directory named `BACKUP' under the location specified by the `FileSystemPath' parameter. * Data Memory, Index Memory, and String Memory * `DataMemory' and `IndexMemory' are `[ndbd]' parameters specifying the size of memory segments used to store the actual records and their indexes. In setting values for these, it is important to understand how `DataMemory' and `IndexMemory' are used, as they usually need to be updated to reflect actual usage by the cluster: * `DataMemory' Options for datamemory-ndbd *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `80M' *Range* `1M-1024G' This parameter defines the amount of space (in bytes) available for storing database records. The entire amount specified by this value is allocated in memory, so it is extremely important that the machine has sufficient physical memory to accommodate it. The memory allocated by `DataMemory' is used to store both the actual records and indexes. There is a 16-byte overhead on each record; an additional amount for each record is incurred because it is stored in a 32KB page with 128 byte page overhead (see below). There is also a small amount wasted per page due to the fact that each record is stored in only one page. For variable-size table attributes in MySQL 5.1, the data is stored on separate datapages, allocated from `DataMemory'. Variable-length records use a fixed-size part with an extra overhead of 4 bytes to reference the variable-size part. The variable-size part has 2 bytes overhead plus 2 bytes per attribute. The maximum record size is currently 8052 bytes. The memory space defined by `DataMemory' is also used to store ordered indexes, which use about 10 bytes per record. Each table row is represented in the ordered index. A common error among users is to assume that all indexes are stored in the memory allocated by `IndexMemory', but this is not the case: Only primary key and unique hash indexes use this memory; ordered indexes use the memory allocated by `DataMemory'. However, creating a primary key or unique hash index also creates an ordered index on the same keys, unless you specify `USING HASH' in the index creation statement. This can be verified by running *Note `ndb_desc -d DB_NAME TABLE_NAME': mysql-cluster-programs-ndb-desc. in the management client. The memory space allocated by `DataMemory' consists of 32KB pages, which are allocated to table fragments. Each table is normally partitioned into the same number of fragments as there are data nodes in the cluster. Thus, for each node, there are the same number of fragments as are set in `NoOfReplicas'. In addition, due to the way in which new pages are allocated when the capacity of the current page is exhausted, there is an additional overhead of approximately 18.75%. When more `DataMemory' is required, more than one new page is allocated, according to the following formula: number of new pages = FLOOR(number of current pages x 0.1875) + 1 For example, if 15 pages are currently allocated to a given table and an insert to this table requires additional storage space, the number of new pages allocated to the table is `FLOOR(15 x 0.1875) + 1 = FLOOR(2.8125) + 1 = 2 + 1 = 3'. Now 15 + 3 = 18 memory pages are allocated to the table. When the last of these 18 pages becomes full, `FLOOR(18 x 0.1875) + 1 = FLOOR(3.3750) + 1 = 3 + 1 = 4' new pages are allocated, so the total number of pages allocated to the table is now 22. *Note*: The `18.75% + 1' overhead is no longer required beginning with MySQL Cluster NDB 6.2.3 and MySQL Cluster NDB 6.3.0. Once a page has been allocated, it is currently not possible to return it to the pool of free pages, except by deleting the table. (This also means that `DataMemory' pages, once allocated to a given table, cannot be used by other tables.) Performing a node recovery also compresses the partition because all records are inserted into empty partitions from other live nodes. The `DataMemory' memory space also contains UNDO information: For each update, a copy of the unaltered record is allocated in the `DataMemory'. There is also a reference to each copy in the ordered table indexes. Unique hash indexes are updated only when the unique index columns are updated, in which case a new entry in the index table is inserted and the old entry is deleted upon commit. For this reason, it is also necessary to allocate enough memory to handle the largest transactions performed by applications using the cluster. In any case, performing a few large transactions holds no advantage over using many smaller ones, for the following reasons: * Large transactions are not any faster than smaller ones * Large transactions increase the number of operations that are lost and must be repeated in event of transaction failure * Large transactions use more memory The default value for `DataMemory' is 80MB; the minimum is 1MB. There is no maximum size, but in reality the maximum size has to be adapted so that the process does not start swapping when the limit is reached. This limit is determined by the amount of physical RAM available on the machine and by the amount of memory that the operating system may commit to any one process. 32-bit operating systems are generally limited to 2-4GB per process; 64-bit operating systems can use more. For large databases, it may be preferable to use a 64-bit operating system for this reason. * `IndexMemory' Options for indexmemory-ndbd *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `18M' *Range* `1M-1T' This parameter controls the amount of storage used for hash indexes in MySQL Cluster. Hash indexes are always used for primary key indexes, unique indexes, and unique constraints. Note that when defining a primary key and a unique index, two indexes will be created, one of which is a hash index used for all tuple accesses as well as lock handling. It is also used to enforce unique constraints. The size of the hash index is 25 bytes per record, plus the size of the primary key. For primary keys larger than 32 bytes another 8 bytes is added. The default value for `IndexMemory' is 18MB. The minimum is 1MB. * `StringMemory' Options for stringmemory-ndbd *Restart Type* system *Permitted Values (>= 5.1.6)* *Type* `numeric' *Default* `5' *Range* `0-4G' This parameter determines how much memory is allocated for strings such as table names, and is specified in an `[ndbd]' or `[ndbd default]' section of the `config.ini' file. A value between `0' and `100' inclusive is interpreted as a percent of the maximum default value, which is calculated based on a number of factors including the number of tables, maximum table name size, maximum size of `.FRM' files, `MaxNoOfTriggers', maximum column name size, and maximum default column value. In general it is safe to assume that the maximum default value is approximately 5 MB for a MySQL Cluster having 1000 tables. A value greater than `100' is interpreted as a number of bytes. Beginning with MySQL Cluster NDB 6.2.18, MySQL Cluster NDB 6.3.24, and MySQL Cluster NDB 7.0.5, the default value is 25--that is, 25 percent of the default maximum, or approximately 25 KB. (Previously, the default value was 5 beginning with MySQL 5.1.6; prior to MySQL 5.1.6, the default was 0.) Under most circumstances, the default value should be sufficient, but when you have a great many Cluster tables (1000 or more), it is possible to get Error 773 `Out of string memory, please modify StringMemory config parameter: Permanent error: Schema error', in which case you should increase this value. `25' (25 percent) is not excessive, and should prevent this error from recurring in all but the most extreme conditions. The following example illustrates how memory is used for a table. Consider this table definition: CREATE TABLE example ( a INT NOT NULL, b INT NOT NULL, c INT NOT NULL, PRIMARY KEY(a), UNIQUE(b) ) ENGINE=NDBCLUSTER; For each record, there are 12 bytes of data plus 12 bytes overhead. Having no nullable columns saves 4 bytes of overhead. In addition, we have two ordered indexes on columns `a' and `b' consuming roughly 10 bytes each per record. There is a primary key hash index on the base table using roughly 29 bytes per record. The unique constraint is implemented by a separate table with `b' as primary key and `a' as a column. This other table consumes an additional 29 bytes of index memory per record in the `example' table as well 8 bytes of record data plus 12 bytes of overhead. Thus, for one million records, we need 58MB for index memory to handle the hash indexes for the primary key and the unique constraint. We also need 64MB for the records of the base table and the unique index table, plus the two ordered index tables. You can see that hash indexes takes up a fair amount of memory space; however, they provide very fast access to the data in return. They are also used in MySQL Cluster to handle uniqueness constraints. Currently, the only partitioning algorithm is hashing and ordered indexes are local to each node. Thus, ordered indexes cannot be used to handle uniqueness constraints in the general case. An important point for both `IndexMemory' and `DataMemory' is that the total database size is the sum of all data memory and all index memory for each node group. Each node group is used to store replicated information, so if there are four nodes with two replicas, there will be two node groups. Thus, the total data memory available is 2 x `DataMemory' for each data node. It is highly recommended that `DataMemory' and `IndexMemory' be set to the same values for all nodes. Data distribution is even over all nodes in the cluster, so the maximum amount of space available for any node can be no greater than that of the smallest node in the cluster. `DataMemory' and `IndexMemory' can be changed, but decreasing either of these can be risky; doing so can easily lead to a node or even an entire MySQL Cluster that is unable to restart due to there being insufficient memory space. Increasing these values should be acceptable, but it is recommended that such upgrades are performed in the same manner as a software upgrade, beginning with an update of the configuration file, and then restarting the management server followed by restarting each data node in turn. Updates do not increase the amount of index memory used. Inserts take effect immediately; however, rows are not actually deleted until the transaction is committed. Transaction parameters The next few `[ndbd]' parameters that we discuss are important because they affect the number of parallel transactions and the sizes of transactions that can be handled by the system. `MaxNoOfConcurrentTransactions' sets the number of parallel transactions possible in a node. `MaxNoOfConcurrentOperations' sets the number of records that can be in update phase or locked simultaneously. Both of these parameters (especially `MaxNoOfConcurrentOperations') are likely targets for users setting specific values and not using the default value. The default value is set for systems using small transactions, to ensure that these do not use excessive memory. `MaxDMLOperationsPerTransaction', added in MySQL Cluster NDB 7.0.26 and MySQL Cluster NDB 7.1.15, sets the maximum number of DML operations that can be performed in a given transaction. * `MaxNoOfConcurrentTransactions' Options for maxnoofconcurrenttransactions-ndbd *Restart Type* system *Permitted Values * *Type* `numeric' *Default* `4096' *Range* `32-4G' Each cluster data node requires a transaction record for each active transaction in the cluster. The task of coordinating transactions is distributed among all of the data nodes. The total number of transaction records in the cluster is the number of transactions in any given node times the number of nodes in the cluster. Transaction records are allocated to individual MySQL servers. Each connection to a MySQL server requires at least one transaction record, plus an additional transaction object per table accessed by that connection. This means that a reasonable minimum for this parameter is MaxNoOfConcurrentTransactions = (maximum number of tables accessed in any single transaction + 1) * number of cluster SQL nodes Suppose that there are 4 SQL nodes using the cluster. A single join involving 5 tables requires 6 transaction records; if there are 5 such joins in a transaction, then 5 * 6 = 30 transaction records are required for this transaction, per MySQL server, or 30 * 4 = 120 transaction records total. This parameter must be set to the same value for all cluster data nodes. This is due to the fact that, when a data node fails, the oldest surviving node re-creates the transaction state of all transactions that were ongoing in the failed node. Changing the value of `MaxNoOfConcurrentTransactions' requires a complete shutdown and restart of the cluster. The default value is 4096. * `MaxNoOfConcurrentOperations' Options for maxnoofconcurrentoperations-ndbd *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `32K' *Range* `32-4G' It is a good idea to adjust the value of this parameter according to the size and number of transactions. When performing transactions of only a few operations each and not involving a great many records, there is no need to set this parameter very high. When performing large transactions involving many records need to set this parameter higher. Records are kept for each transaction updating cluster data, both in the transaction coordinator and in the nodes where the actual updates are performed. These records contain state information needed to find UNDO records for rollback, lock queues, and other purposes. This parameter should be set to the number of records to be updated simultaneously in transactions, divided by the number of cluster data nodes. For example, in a cluster which has four data nodes and which is expected to handle 1,000,000 concurrent updates using transactions, you should set this value to 1000000 / 4 = 250000. Read queries which set locks also cause operation records to be created. Some extra space is allocated within individual nodes to accommodate cases where the distribution is not perfect over the nodes. When queries make use of the unique hash index, there are actually two operation records used per record in the transaction. The first record represents the read in the index table and the second handles the operation on the base table. The default value is 32768. This parameter actually handles two values that can be configured separately. The first of these specifies how many operation records are to be placed with the transaction coordinator. The second part specifies how many operation records are to be local to the database. A very large transaction performed on an eight-node cluster requires as many operation records in the transaction coordinator as there are reads, updates, and deletes involved in the transaction. However, the operation records of the are spread over all eight nodes. Thus, if it is necessary to configure the system for one very large transaction, it is a good idea to configure the two parts separately. `MaxNoOfConcurrentOperations' will always be used to calculate the number of operation records in the transaction coordinator portion of the node. It is also important to have an idea of the memory requirements for operation records. These consume about 1KB per record. * `MaxNoOfLocalOperations' Options for maxnooflocaloperations-ndbd *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `UNDEFINED' *Range* `32-4G' By default, this parameter is calculated as 1.1 x `MaxNoOfConcurrentOperations'. This fits systems with many simultaneous transactions, none of them being very large. If there is a need to handle one very large transaction at a time and there are many nodes, it is a good idea to override the default value by explicitly specifying this parameter. * `MaxDMLOperationsPerTransaction' Options for maxdmloperationspertransaction-ndbd *Version Introduced* 5.1.56-ndb-7.0.26, 5.1.56-ndb-7.1.15 *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `4294967295' *Range* `32-4294967295' *Permitted Values * *Type* `numeric' *Default* `4294967295' *Range* `32-4294967295' Added in MySQL Cluster NDB 7.0.26 and MySQL Cluster NDB 7.1.15, this parameter limits the size of a transaction. The transaction is aborted if it requires more than this many DML operations. The minimum number of operations per transaction is 32; however, you can set `MaxDMLOperationsPerTransaction' to 0 to disable any limitation on the number of DML operations per transaction. The maximum (and default) is 4294967295. Transaction temporary storage The next set of `[ndbd]' parameters is used to determine temporary storage when executing a statement that is part of a Cluster transaction. All records are released when the statement is completed and the cluster is waiting for the commit or rollback. The default values for these parameters are adequate for most situations. However, users with a need to support transactions involving large numbers of rows or operations may need to increase these values to enable better parallelism in the system, whereas users whose applications require relatively small transactions can decrease the values to save memory. * `MaxNoOfConcurrentIndexOperations' Options for maxnoofconcurrentindexoperations-ndbd *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `8K' *Range* `0-4G' For queries using a unique hash index, another temporary set of operation records is used during a query's execution phase. This parameter sets the size of that pool of records. Thus, this record is allocated only while executing a part of a query. As soon as this part has been executed, the record is released. The state needed to handle aborts and commits is handled by the normal operation records, where the pool size is set by the parameter `MaxNoOfConcurrentOperations'. The default value of this parameter is 8192. Only in rare cases of extremely high parallelism using unique hash indexes should it be necessary to increase this value. Using a smaller value is possible and can save memory if the DBA is certain that a high degree of parallelism is not required for the cluster. * `MaxNoOfFiredTriggers' Options for maxnooffiredtriggers-ndbd *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `4000' *Range* `0-4G' The default value of `MaxNoOfFiredTriggers' is 4000, which is sufficient for most situations. In some cases it can even be decreased if the DBA feels certain the need for parallelism in the cluster is not high. A record is created when an operation is performed that affects a unique hash index. Inserting or deleting a record in a table with unique hash indexes or updating a column that is part of a unique hash index fires an insert or a delete in the index table. The resulting record is used to represent this index table operation while waiting for the original operation that fired it to complete. This operation is short-lived but can still require a large number of records in its pool for situations with many parallel write operations on a base table containing a set of unique hash indexes. * `TransactionBufferMemory' Options for transactionbuffermemory-ndbd *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `1M' *Range* `1K-4G' The memory affected by this parameter is used for tracking operations fired when updating index tables and reading unique indexes. This memory is used to store the key and column information for these operations. It is only very rarely that the value for this parameter needs to be altered from the default. The default value for `TransactionBufferMemory' is 1MB. Normal read and write operations use a similar buffer, whose usage is even more short-lived. The compile-time parameter `ZATTRBUF_FILESIZE' (found in `ndb/src/kernel/blocks/Dbtc/Dbtc.hpp') set to 4000 x 128 bytes (500KB). A similar buffer for key information, `ZDATABUF_FILESIZE' (also in `Dbtc.hpp') contains 4000 x 16 = 62.5KB of buffer space. `Dbtc' is the module that handles transaction coordination. Scans and buffering There are additional `[ndbd]' parameters in the `Dblqh' module (in `ndb/src/kernel/blocks/Dblqh/Dblqh.hpp') that affect reads and updates. These include `ZATTRINBUF_FILESIZE', set by default to 10000 x 128 bytes (1250KB) and `ZDATABUF_FILE_SIZE', set by default to 10000*16 bytes (roughly 156KB) of buffer space. To date, there have been neither any reports from users nor any results from our own extensive tests suggesting that either of these compile-time limits should be increased. * `MaxNoOfConcurrentScans' Options for maxnoofconcurrentscans-ndbd *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `256' *Range* `2-500' This parameter is used to control the number of parallel scans that can be performed in the cluster. Each transaction coordinator can handle the number of parallel scans defined for this parameter. Each scan query is performed by scanning all partitions in parallel. Each partition scan uses a scan record in the node where the partition is located, the number of records being the value of this parameter times the number of nodes. The cluster should be able to sustain `MaxNoOfConcurrentScans' scans concurrently from all nodes in the cluster. Scans are actually performed in two cases. The first of these cases occurs when no hash or ordered indexes exists to handle the query, in which case the query is executed by performing a full table scan. The second case is encountered when there is no hash index to support the query but there is an ordered index. Using the ordered index means executing a parallel range scan. The order is kept on the local partitions only, so it is necessary to perform the index scan on all partitions. The default value of `MaxNoOfConcurrentScans' is 256. The maximum value is 500. * `MaxNoOfLocalScans' Options for maxnooflocalscans-ndbd *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `UNDEFINED' *Range* `32-4G' Specifies the number of local scan records if many scans are not fully parallelized. In MySQL Cluster NDB 7.2.0 and later, when the number of local scan records is not provided, it is calculated as 4 times the product of `MaxNoOfConcurrentScans' and the number of data nodes in the system. (Previously, it was calculated as the product of `MaxNoOfConcurrentScans' and the number of data nodes.) The minimum value is 32. * `BatchSizePerLocalScan' Options for batchsizeperlocalscan-ndbd *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `64' *Range* `1-992' This parameter is used to calculate the number of lock records used to handle concurrent scan operations. The default value is 64; this value has a strong connection to the `BatchSize' defined in the SQL nodes. * `LongMessageBuffer' Options for longmessagebuffer-ndbd *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `1M' *Range* `512K-4G' *Permitted Values * *Type* `numeric' *Default* `4M' *Range* `512K-4G' This is an internal buffer used for passing messages within individual nodes and between nodes. In MySQL Cluster NDB 6.4.3 and earlier, the default is 1MB; beginning with MySQL Cluster NDB 7.0.4, it is 4MB. This parameter seldom needs to be changed from the default. However, when replicating a MySQL Cluster using *Note `ndbmtd': mysql-cluster-programs-ndbmtd. for the data nodes, you may need to increase this value to 8MB (or possibly more) to prevent data node instability, because *Note `ndbmtd': mysql-cluster-programs-ndbmtd. uses much more of this resource than *Note `ndbd': mysql-cluster-programs-ndbd. does. Beginning with MySQL Cluster NDB 7.0.13 and MySQL Cluster NDB 7.1.2, this should no longer be necessary when using *Note `ndbmtd': mysql-cluster-programs-ndbmtd. with MySQL Cluster Replication (Bug#46914). * `MaxParallelScansPerFragment' Options for maxparallelscansperfragment-ndbd *Version Introduced* 5.1.51-ndb-7.0.23, 5.1.51-ndb-7.1.21 *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `32' *Range* `1-1G' *Permitted Values * *Type* `numeric' *Default* `32' *Range* `1-1G' *Permitted Values * *Type* `numeric' *Default* `256' *Range* `1-1G' Beginning with MySQL Cluster NDB 7.0.23 and MySQL Cluster NDB 7.1.12, it is possible to copnfigure the maximum number of parallel scans (`TUP' scans and `TUX' scans) allowed before they begin queuing for serial handling. (Previously, the maximum number of parallel scans per fragment was fixed at 32.) You can increase this to take advantage of any unused CPU when performing large number of scans in parallel and improve their performance. Beginning with MySQL Cluster NDB 7.2.0, the default value for this parameter is increased from 32 to 256. * Memory Allocation * `MaxAllocate' This is the maximum size of the memory unit to use when allocating memory for tables. In cases where *Note `NDB': mysql-cluster. gives `Out of memory' errors, but it is evident by examining the cluster logs or the output of `DUMP 1000' (see `DUMP 1000' (http://dev.mysql.com/doc/ndbapi/en/ndb-internals-dump-command-1000.html)) that all available memory has not yet been used, you can increase the value of this parameter (or `MaxNoOfTables', or both) to cause *Note `NDB': mysql-cluster. to make sufficient memory available. This parameter was introduced in MySQL 5.1.20, MySQL Cluster NDB 6.1.12 and MySQL Cluster NDB 6.2.3. Logging and checkpointing The following `[ndbd]' parameters control log and checkpoint behavior. * `NoOfFragmentLogFiles' Options for nooffragmentlogfiles-ndbd *Restart Type* initial, node *Permitted Values (>= 5.1.0)* *Type* `numeric' *Default* `16' *Range* `3-4G' This parameter sets the number of REDO log files for the node, and thus the amount of space allocated to REDO logging. Because the REDO log files are organized in a ring, it is extremely important that the first and last log files in the set (sometimes referred to as the `head' and `tail' log files, respectively) do not meet. When these approach one another too closely, the node begins aborting all transactions encompassing updates due to a lack of room for new log records. A `REDO' log record is not removed until the required number of local checkpoints has been completed since that log record was inserted (prior to MySQL Cluster NDB 6.3.8, this was 3 local checkpoints; in later versions of MySQL Cluster, only 2 local checkpoints are necessary). Checkpointing frequency is determined by its own set of configuration parameters discussed elsewhere in this chapter. How these parameters interact and proposals for how to configure them are discussed in *Note mysql-cluster-config-lcp-params::. The default parameter value is 16, which by default means 16 sets of 4 16MB files for a total of 1024MB. Beginning with MySQL Cluster NDB 6.1.1, the size of the individual log files is configurable using the `FragmentLogFileSize' parameter. In scenarios requiring a great many updates, the value for `NoOfFragmentLogFiles' may need to be set as high as 300 or even higher to provide sufficient space for REDO logs. If the checkpointing is slow and there are so many writes to the database that the log files are full and the log tail cannot be cut without jeopardizing recovery, all updating transactions are aborted with internal error code 410 (`Out of log file space temporarily'). This condition prevails until a checkpoint has completed and the log tail can be moved forward. *Important*: This parameter cannot be changed `on the fly'; you must restart the node using `--initial'. If you wish to change this value for all data nodes in a running cluster, you can do so using a rolling node restart (using `--initial' when starting each data node). * `FragmentLogFileSize' Options for fragmentlogfilesize-ndbd *Version Introduced* 5.1.15-ndb-6.1.11 *Restart Type* initial, node *Permitted Values * *Type* `numeric' *Default* `16M' *Range* `4M-1G' Setting this parameter enables you to control directly the size of redo log files. This can be useful in situations when MySQL Cluster is operating under a high load and it is unable to close fragment log files quickly enough before attempting to open new ones (only 2 fragment log files can be open at one time); increasing the size of the fragment log files gives the cluster more time before having to open each new fragment log file. The default value for this parameter is 16M. `FragmentLogFileSize' was added in MySQL Cluster NDB 6.1.11. For more information about fragment log files, see the description for `NoOfFragmentLogFiles'. * `InitFragmentLogFiles' Options for initfragmentlogfiles-ndbd *Version Introduced* 5.1.29-ndb-6.3.19 *Restart Type* initial, node *Permitted Values * *Type* `string' *Default* `' *Range* `-' By default, fragment log files are created sparsely when performing an initial start of a data node--that is, depending on the operating system and file system in use, not all bytes are necessarily written to disk. Beginning with MySQL Cluster NDB 6.3.19, it is possible to override this behavior and force all bytes to be written regardless of the platform and file system type being used by mean of this parameter. `InitFragmentLogFiles' takes one of two values: * `SPARSE'. Fragment log files are created sparsely. This is the default value. * `FULL'. Force all bytes of the fragment log file to be written to disk. Depending on your operating system and file system, setting `InitFragmentLogFiles=FULL' may help eliminate I/O errors on writes to the REDO log. * `MaxNoOfOpenFiles' Options for maxnoofopenfiles-ndbd *Restart Type* node *Permitted Values (<= 5.1.15)* *Type* `numeric' *Default* `40' *Range* `20-4G' *Permitted Values (>= 5.1.16)* *Type* `numeric' *Default* `0' *Range* `20-4G' This parameter sets a ceiling on how many internal threads to allocate for open files. _Any situation requiring a change in this parameter should be reported as a bug_. The default value is 0. (Prior to MySQL 5.1.16, the default was 40.) However, the minimum value to which this parameter can be set is 20. * `InitialNoOfOpenFiles' Options for initialnoofopenfiles-ndbd *Version Introduced* 5.1.9 *Restart Type* node *Permitted Values (>= 5.1.9)* *Type* `numeric' *Default* `27' *Range* `20-4G' This parameter sets the initial number of internal threads to allocate for open files. The default value is 27. * `MaxNoOfSavedMessages' Options for maxnoofsavedmessages-ndbd *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `25' *Range* `0-4G' This parameter sets the maximum number of trace files that are kept before overwriting old ones. Trace files are generated when, for whatever reason, the node crashes. The default is 25 trace files. * `MaxLCPStartDelay' Options for maxlcpstartdelay-ndbd *Version Introduced* 5.1.32-ndb-6.3.23, 5.1.32-ndb-6.4.3 *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `0' *Range* `0-600' *Permitted Values * *Type* `numeric' *Default* `0' *Range* `0-600' In parallel data node recovery (supported in MySQL Cluster NDB 6.3.8 and later), only table data is actually copied and synchronized in parallel; synchronization of metadata such as dictionary and checkpoint information is done in a serial fashion. In addition, recovery of dictionary and checkpoint information cannot be executed in parallel with performing of local checkpoints. This means that, when starting or restarting many data nodes concurrently, data nodes may be forced to wait while a local checkpoint is performed, which can result in longer node recovery times. Beginning with MySQL Cluster NDB 6.3.23 and MySQL Cluster NDB 6.4.3, it is possible to force a delay in the local checkpoint to permit more (and possibly all) data nodes to complete metadata synchronization; once each data node's metadata synchronization is complete, all of the data nodes can recover table data in parallel, even while the local checkpoint is being executed. To force such a delay, you can set `MaxLCPStartDelay', which determines the number of seconds the cluster can wait to begin a local checkpoint while data nodes continue to synchronize metadata. This parameter should be set in the `[ndbd default]' section of the `config.ini' file, so that it is the same for all data nodes. The maximum value is 600; the default is 0. Metadata objects The next set of `[ndbd]' parameters defines pool sizes for metadata objects, used to define the maximum number of attributes, tables, indexes, and trigger objects used by indexes, events, and replication between clusters. Note that these act merely as `suggestions' to the cluster, and any that are not specified revert to the default values shown. * `MaxNoOfAttributes' Options for maxnoofattributes-ndbd *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `1000' *Range* `32-4G' This parameter sets a suggested maximum number of attributes that can be defined in the cluster; like `MaxNoOfTables', it is not intended to function as a hard upper limit. Prior to MySQL Cluster NDB 6.3.45, MySQL Cluster NDB 7.0.26, and MySQL Cluster NDB 7.1.15, this parameter was sometimes treated as a hard limit for certain operations. This caused problems with MySQL Cluster Replication, when it was possible to create more tables than could be replicated, and sometimes led to confusion when it was possible (or not possible, depending on the circumstances) to create more than `MaxNoOfAttributes' attributes. (Bug #61684) The default value is 1000, with the minimum possible value being 32. The maximum is 4294967039. Each attribute consumes around 200 bytes of storage per node due to the fact that all metadata is fully replicated on the servers. When setting `MaxNoOfAttributes', it is important to prepare in advance for any *Note `ALTER TABLE': alter-table. statements that you might want to perform in the future. This is due to the fact, during the execution of *Note `ALTER TABLE': alter-table. on a Cluster table, 3 times the number of attributes as in the original table are used, and a good practice is to permit double this amount. For example, if the MySQL Cluster table having the greatest number of attributes (GREATEST_NUMBER_OF_ATTRIBUTES) has 100 attributes, a good starting point for the value of `MaxNoOfAttributes' would be `6 * GREATEST_NUMBER_OF_ATTRIBUTES = 600'. You should also estimate the average number of attributes per table and multiply this by `MaxNoOfTables'. If this value is larger than the value obtained in the previous paragraph, you should use the larger value instead. Assuming that you can create all desired tables without any problems, you should also verify that this number is sufficient by trying an actual *Note `ALTER TABLE': alter-table. after configuring the parameter. If this is not successful, increase `MaxNoOfAttributes' by another multiple of `MaxNoOfTables' and test it again. * `MaxNoOfTables' Options for maxnooftables-ndbd *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `128' *Range* `8-20320' A table object is allocated for each table and for each unique hash index in the cluster. This parameter sets a suggested maximum number of table objects for the cluster as a whole; like `MaxNoOfAttributes', it is not intended to function as a hard upper limit. Prior to MySQL Cluster NDB 6.3.45, MySQL Cluster NDB 7.0.26, and MySQL Cluster NDB 7.1.15, this parameter was sometimes treated as a hard limit for certain operations. This caused problems with MySQL Cluster Replication, when it was possible to create more tables than could be replicated, and sometimes led to confusion when it was possible (or not possible, depending on the circumstances) to create more than `MaxNoOfTables' tables. For each attribute that has a *Note `BLOB': blob. data type an extra table is used to store most of the *Note `BLOB': blob. data. These tables also must be taken into account when defining the total number of tables. The default value of this parameter is 128. The minimum is 8 and the maximum is 20320. Each table object consumes approximately 20KB per node. *Note*: The sum of `MaxNoOfTables', `MaxNoOfOrderedIndexes', and `MaxNoOfUniqueHashIndexes' must not exceed `2^32 - 2' (4294967294). * `MaxNoOfOrderedIndexes' Options for maxnooforderedindexes-ndbd *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `128' *Range* `0-4G' For each ordered index in the cluster, an object is allocated describing what is being indexed and its storage segments. By default, each index so defined also defines an ordered index. Each unique index and primary key has both an ordered index and a hash index. `MaxNoOfOrderedIndexes' sets the total number of hash indexes that can be in use in the system at any one time. The default value of this parameter is 128. Each hash index object consumes approximately 10KB of data per node. *Note*: The sum of `MaxNoOfTables', `MaxNoOfOrderedIndexes', and `MaxNoOfUniqueHashIndexes' must not exceed `2^32 - 2' (4294967294). * `MaxNoOfUniqueHashIndexes' Options for maxnoofuniquehashindexes-ndbd *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `64' *Range* `0-4G' For each unique index that is not a primary key, a special table is allocated that maps the unique key to the primary key of the indexed table. By default, an ordered index is also defined for each unique index. To prevent this, you must specify the `USING HASH' option when defining the unique index. The default value is 64. Each index consumes approximately 15KB per node. *Note*: The sum of `MaxNoOfTables', `MaxNoOfOrderedIndexes', and `MaxNoOfUniqueHashIndexes' must not exceed `2^32 - 2' (4294967294). * `MaxNoOfTriggers' Options for maxnooftriggers-ndbd *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `768' *Range* `0-4G' Internal update, insert, and delete triggers are allocated for each unique hash index. (This means that three triggers are created for each unique hash index.) However, an _ordered_ index requires only a single trigger object. Backups also use three trigger objects for each normal table in the cluster. Replication between clusters also makes use of internal triggers. This parameter sets the maximum number of trigger objects in the cluster. The default value is 768. * `MaxNoOfIndexes' This parameter is deprecated in MySQL Cluster 5.1 and later; you should use `MaxNoOfOrderedIndexes' and `MaxNoOfUniqueHashIndexes' instead. This parameter is used only by unique hash indexes. There needs to be one record in this pool for each unique hash index defined in the cluster. The default value of this parameter is 128. * `MaxNoOfSubscriptions' Options for maxnoofsubscriptions-ndbd *Version Introduced* 5.1.23-ndb-6.2.10, 5.1.23-ndb-6.3.7 *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `0' *Range* `0-4G' *Permitted Values * *Type* `numeric' *Default* `0' *Range* `0-4G' Each *Note `NDB': mysql-cluster. table in a MySQL Cluster requires a subscription in the NDB kernel. For some NDB API applications, it may be necessary or desirable to change this parameter, which became available in MySQL Cluster NDB 6.2.10 and MySQL Cluster NDB 6.3.7. However, for normal usage with MySQL servers acting as SQL nodes, there is not any need to do so. The default value for `MaxNoOfSubscriptions' is 0, which is treated as equal to `MaxNoOfTables'. * `MaxNoOfSubscribers' Options for maxnoofsubscribers-ndbd *Version Introduced* 5.1.23-ndb-6.2.10, 5.1.23-ndb-6.3.7 *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `0' *Range* `0-4G' *Permitted Values * *Type* `numeric' *Default* `0' *Range* `0-4G' This parameter, added in MySQL Cluster NDB 6.2.10 and MySQL Cluster NDB 6.3.7, is of interest only when using MySQL Cluster Replication. The default value is 0, which is treated as `2 * MaxNoOfTables'; that is, there is one subscription per *Note `NDB': mysql-cluster. table for each of two MySQL servers (one acting as the replication master and the other as the slave). When using circular replication, multi-master replcation, and other replication setups involving more than 2 MySQL servers, you should increase this parameter to the number of *Note `mysqld': mysqld. processes included in replication (this is often, but not always, the same as the number of clusters). For example, if you have a circular replication setup using three MySQL Clusters, with one *Note `mysqld': mysqld. attached to each cluster, and each of these *Note `mysqld': mysqld. processes acts as a master and as a slave, you should set `MaxNoOfSubscribers' equal to `3 * MaxNoOfTables'. For more information, see *Note mysql-cluster-replication::. * `MaxNoOfConcurrentSubOperations' Options for maxnoofconcurrentsuboperations-ndbd *Version Introduced* 5.1.23-ndb-6.2.10, 5.1.23-ndb-6.3.7 *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `256' *Range* `0-4G' *Permitted Values * *Type* `numeric' *Default* `256' *Range* `0-4G' This parameter sets a ceiling on the number of operations that can be performed by all API nodes in the cluster at one time. The default value (256) is sufficient for normal operations, and might need to be adjusted only in scenarios where there are a great many API nodes each performing a high volume of operations concurrently. This parameter was added in MySQL Cluster NDB 6.2.10 and MySQL Cluster NDB 6.3.7. Boolean parameters The behavior of data nodes is also affected by a set of `[ndbd]' parameters taking on boolean values. These parameters can each be specified as `TRUE' by setting them equal to `1' or `Y', and as `FALSE' by setting them equal to `0' or `N'. * `LockPagesInMainMemory' Options for lockpagesinmainmemory-ndbd *Restart Type* node *Permitted Values (>= 5.1.0, <= 5.1.14)* *Type* `boolean' *Default* `0' *Range* `0-1' *Permitted Values (>= 5.1.15)* *Type* `numeric' *Default* `0' *Range* `0-2' For a number of operating systems, including Solaris and Linux, it is possible to lock a process into memory and so avoid any swapping to disk. This can be used to help guarantee the cluster's real-time characteristics. Beginning with MySQL 5.1.15 and MySQL Cluster NDB 6.1.1, this parameter takes one of the integer values `0', `1', or `2', which act as follows: * `0': Disables locking. This is the default value. * `1': Performs the lock after allocating memory for the process. * `2': Performs the lock before memory for the process is allocated. Previously, this parameter was a Boolean. `0' or `false' was the default setting, and disabled locking. `1' or `true' enabled locking of the process after its memory was allocated. *Important*: Beginning with MySQL 5.1.15 and MySQL Cluster NDB 6.1.1, it is no longer possible to use `true' or `false' for the value of this parameter; when upgrading from a previous version, you must change the value to `0', `1', or `2'. Prior to MySQL Cluster NDB 6.3.31 and MySQL Cluster NDB 7.0.11, setting this parameter did not cause the stated memory to be allocated when the node was started, but rather only when the memory was used by the data node process for other reasons. (Bug#37430) *Note*: If the operating system is not configured to permit unprivileged users to lock pages, then the data node process making use of this parameter may have to be run as system root. (`LockPagesInMainMemory' uses the `mlockall' function. From Linux kernel 2.6.9, unprivileged users can lock memory as limited by `max locked memory'. For more information, see `ulimit -l' and `http://linux.die.net/man/2/mlock'). * `StopOnError' Options for stoponerror-ndbd *Restart Type* node *Permitted Values * *Type* `boolean' *Default* `true' *Range* `-' This parameter specifies whether an *Note `ndbd': mysql-cluster-programs-ndbd. process should exit or perform an automatic restart when an error condition is encountered. This feature is enabled by default. * `Diskless' Options for diskless-ndbd *Restart Type* initial, system *Permitted Values * *Type* `boolean' *Default* `0' *Range* `0-1' It is possible to specify MySQL Cluster tables as _diskless_, meaning that tables are not checkpointed to disk and that no logging occurs. Such tables exist only in main memory. A consequence of using diskless tables is that neither the tables nor the records in those tables survive a crash. However, when operating in diskless mode, it is possible to run *Note `ndbd': mysql-cluster-programs-ndbd. on a diskless computer. *Important*: This feature causes the _entire_ cluster to operate in diskless mode. When this feature is enabled, Cluster online backup is disabled. In addition, a partial start of the cluster is not possible. `Diskless' is disabled by default. * `ODirect' Options for odirect-ndbd *Version Introduced* 5.1.15-ndb-6.1.11, 5.1.19-ndb-6.2.3, 5.1.19-ndb-6.3.0 *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `0' *Range* `0-1' *Permitted Values * *Type* `numeric' *Default* `0' *Range* `0-1' *Permitted Values * *Type* `numeric' *Default* `0' *Range* `0-1' Enabling this parameter causes *Note `NDB': mysql-cluster. to attempt using `O_DIRECT' writes for LCP, backups, and redo logs, often lowering `kswapd' and CPU usage. When using MySQL Cluster on Linux, enable `ODirect' if you are using a 2.6 or later kernel. This parameter was added in MySQL 5.1.20, MySQL Cluster NDB 6.1.11, MySQL Cluster NDB 6.2.3, and MySQL Cluster NDB 6.3.0. `ODirect' is disabled by default. * `RestartOnErrorInsert' Options for restartonerrorinsert-ndbd *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `2' *Range* `0-4' This feature is accessible only when building the debug version where it is possible to insert errors in the execution of individual blocks of code as part of testing. This feature is disabled by default. * `CompressedBackup' Options for compressedbackup-ndbd *Version Introduced* 5.1.23-ndb-6.3.7 *Restart Type* node *Permitted Values * *Type* `boolean' *Default* `false' *Range* `-' Setting this parameter to `1' causes backup files to be compressed. The compression used is equivalent to `gzip --fast', and can save 50% or more of the space required on the data node to store uncompressed backup files. Compressed backups can be enabled for individual data nodes, or for all data nodes (by setting this parameter in the `[ndbd default]' section of the `config.ini' file). *Important*: You cannot restore a compressed backup to a cluster running a MySQL version that does not support this feature. The default value is `0' (disabled). This parameter was introduced in MySQL Cluster NDB 6.3.7. * `CompressedLCP' Options for compressedlcp-ndbd *Version Introduced* 5.1.23-ndb-6.3.7 *Restart Type* node *Permitted Values * *Type* `boolean' *Default* `false' *Range* `-' Setting this parameter to `1' causes local checkpoint files to be compressed. The compression used is equivalent to `gzip --fast', and can save 50% or more of the space required on the data node to store uncompressed checkpoint files. Compressed LCPs can be enabled for individual data nodes, or for all data nodes (by setting this parameter in the `[ndbd default]' section of the `config.ini' file). *Important*: You cannot restore a compressed local checkpoint to a cluster running a MySQL version that does not support this feature. The default value is `0' (disabled). This parameter was introduced in MySQL Cluster NDB 6.3.7. * Controlling Timeouts, Intervals, and Disk Paging * There are a number of `[ndbd]' parameters specifying timeouts and intervals between various actions in Cluster data nodes. Most of the timeout values are specified in milliseconds. Any exceptions to this are mentioned where applicable. * `TimeBetweenWatchDogCheck' Options for timebetweenwatchdogcheck-ndbd *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `6000' *Range* `70-4G' To prevent the main thread from getting stuck in an endless loop at some point, a `watchdog' thread checks the main thread. This parameter specifies the number of milliseconds between checks. If the process remains in the same state after three checks, the watchdog thread terminates it. This parameter can easily be changed for purposes of experimentation or to adapt to local conditions. It can be specified on a per-node basis although there seems to be little reason for doing so. The default timeout is 6000 milliseconds (6 seconds). * `TimeBetweenWatchDogCheckInitial' Options for timebetweenwatchdogcheckinitial-ndbd *Version Introduced* 5.1.20 *Restart Type* node *Permitted Values (>= 5.1.20)* *Type* `numeric' *Default* `6000' *Range* `70-4G' This is similar to the `TimeBetweenWatchDogCheck' parameter, except that `TimeBetweenWatchDogCheckInitial' controls the amount of time that passes between execution checks inside a database node in the early start phases during which memory is allocated. The default timeout is 6000 milliseconds (6 seconds). This parameter was added in MySQL 5.1.20. * `StartPartialTimeout' Options for startpartialtimeout-ndbd *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `30000' *Range* `0-4G' This parameter specifies how long the Cluster waits for all data nodes to come up before the cluster initialization routine is invoked. This timeout is used to avoid a partial Cluster startup whenever possible. This parameter is overridden when performing an initial start or initial restart of the cluster. The default value is 30000 milliseconds (30 seconds). 0 disables the timeout, in which case the cluster may start only if all nodes are available. * `StartPartitionedTimeout' Options for startpartitionedtimeout-ndbd *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `60000' *Range* `0-4G' If the cluster is ready to start after waiting for `StartPartialTimeout' milliseconds but is still possibly in a partitioned state, the cluster waits until this timeout has also passed. If `StartPartitionedTimeout' is set to 0, the cluster waits indefinitely. This parameter is overridden when performing an initial start or initial restart of the cluster. The default timeout is 60000 milliseconds (60 seconds). * `StartFailureTimeout' Options for startfailuretimeout-ndbd *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `0' *Range* `0-4G' If a data node has not completed its startup sequence within the time specified by this parameter, the node startup fails. Setting this parameter to 0 (the default value) means that no data node timeout is applied. For nonzero values, this parameter is measured in milliseconds. For data nodes containing extremely large amounts of data, this parameter should be increased. For example, in the case of a data node containing several gigabytes of data, a period as long as 10-15 minutes (that is, 600000 to 1000000 milliseconds) might be required to perform a node restart. * `StartNoNodeGroupTimeout' Options for startnonodegrouptimeout-ndbd *Version Introduced* 5.1.56-ndb-7.0.24,5.1.56-ndb-7.1.13 *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `15000' *Range* `0-4294967039' When a data node is configured with `Nodegroup = 65536', is regarded as not being assigned to any node group. When that is done, the cluster waits `StartNoNodegroupTimeout' milliseconds, then treats such nodes as though they had been added to the list passed to the `--nowait-nodes' option, and starts. The default value is `15000' (that is, the management server waits 15 seconds). Setting this parameter equal to `0' means that the cluster waits indefinitely. `StartNoNodegroupTimeout' must be the same for all data nodes in the cluster; for this reason, you should always set it in the `[ndbd default]' section of the `config.ini' file, rather than for individual data nodes. This parameter was added in MySQL Cluster NDB 7.0.24 and MySQL Cluster NDB 7.1.13. See *Note mysql-cluster-online-add-node::, for more information. * `HeartbeatIntervalDbDb' Options for heartbeatintervaldbdb-ndbd *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `1500' *Range* `10-4G' One of the primary methods of discovering failed nodes is by the use of heartbeats. This parameter states how often heartbeat signals are sent and how often to expect to receive them. After missing three heartbeat intervals in a row, the node is declared dead. Thus, the maximum time for discovering a failure through the heartbeat mechanism is four times the heartbeat interval. In MySQL Cluster NDB 7.2.0 and later, the default heartbeat interval is 5000 milliseconds (5 seconds). Previously, the default was 1500 milliseconds (1.5 seconds). This parameter must not be changed drastically and should not vary widely between nodes. If one node uses 5000 milliseconds and the node watching it uses 1000 milliseconds, obviously the node will be declared dead very quickly. This parameter can be changed during an online software upgrade, but only in small increments. See also *Note mysql-cluster-network-latency-issues::. * `HeartbeatIntervalDbApi' Options for heartbeatintervaldbapi-ndbd *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `1500' *Range* `100-4G' Each data node sends heartbeat signals to each MySQL server (SQL node) to ensure that it remains in contact. If a MySQL server fails to send a heartbeat in time it is declared `dead,' in which case all ongoing transactions are completed and all resources released. The SQL node cannot reconnect until all activities initiated by the previous MySQL instance have been completed. The three-heartbeat criteria for this determination are the same as described for `HeartbeatIntervalDbDb'. The default interval is 1500 milliseconds (1.5 seconds). This interval can vary between individual data nodes because each data node watches the MySQL servers connected to it, independently of all other data nodes. For more information, see *Note mysql-cluster-network-latency-issues::. * `HeartbeatOrder' Options for heartbeatorder-ndbd *Version Introduced* 5.1.47-ndb-6.3.35, 5.1.47-ndb-7.0.16, 5.1.47-ndb-7.1.5 *Restart Type* system *Permitted Values * *Type* `numeric' *Default* `0' *Range* `0-65535' Data nodes send heartbeats to one another in a circular fashion whereby each data node monitors the previous one. If a heartbeat is not detected by a given data node, this node declares the previous data node in the circle `dead' (that is, no longer accessible by the cluster). The determination that a data node is dead is done globally; in other words; once a data node is declared dead, it is regarded as such by all nodes in the cluster. It is possible for heartbeats between data nodes residing on different hosts to be too slow compared to heartbeats between other pairs of nodes (for example, due to a very low heartbeat interval or temporary connection problem), such that a data node is declared dead, even though the node can still function as part of the cluster. . In this type of situation, it may be that the order in which heartbeats are transmitted between data nodes makes a difference as to whether or not a particular data node is declared dead. If this declaration occurs unnecessarily, this can in turn lead to the unnecessary loss of a node group and as thus to a failure of the cluster. Consider a setup where there are 4 data nodes A, B, C, and D running on 2 host computers `host1' and `host2', and that these data nodes make up 2 node groups, as shown in the following table: `host1' `host2' _Node Group 0_: Node A Node B _Node Group 1_: Node C Node D Suppose the heartbeats are transmitted in the order A->B->C->D->A. In this case, the loss of the heartbeat between the hosts causes node B to declare node A dead and node C to declare node B dead. This results in loss of Node Group 0, and so the cluster fails. On the other hand, if the order of transmission is A->B->D->C->A (and all other conditions remain as previously stated), the loss of the heartbeat causes nodes A and D to be declared dead; in this case, each node group has one surviving node, and the cluster survives. Priot to MySQL Cluster NDB 6.3.35, MySQL Cluster NDB 7.0.16, and MySQL Cluster NDB 7.1.5, the order of of heartbeat transmission between data nodes was always automatically determined by `NDB'. However, beginning with these versions, the `HeartbeatOrder' configuration parameter makes the order of heartbeat transmission user-configurable. The default value for `HeartbeatOrder' is zero; allowing the default value to be used on all data nodes causes the order of heartbeat transmission to be determined by `NDB'. If this parameter is used, it must be set to a nonzero value (maximum 65535) for every data node in the cluster, and this value must be unique for each data node; this causes the heartbeat transmission to proceed from data node to data node in the order of their `HeartbeatOrder' values from lowest to highest (and then directly from the data node having the highest `HeartbeatOrder' to the data node having the lowest value, to complete the circle). The values need not be consecutive; for example, to force the heartbeat transmission order A->B->D->C->A in the scenario outlined previously, you could set the `HeartbeatOrder' values as shown here: Node `HeartbeatOrder' A 10 B 20 C 30 D 25 To use this parameter to change the heartbeat transmission order in a running MySQL Cluster, you must first set `HeartbeatOrder' for each data node in the cluster in the global configuration (`config.ini') file (or files). To cause the change to take effect, you must perform either of the following: * A complete shutdown and restart of the entire cluster. * 2 rolling restarts of the cluster in succession. _All nodes must be restarted in the same order in both rolling restarts_. You can use `DUMP 908' to observe the effect of this parameter in the data node logs. * `TimeBetweenLocalCheckpoints' Options for timebetweenlocalcheckpoints-ndbd *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `20' *Range* `0-31' This parameter is an exception in that it does not specify a time to wait before starting a new local checkpoint; rather, it is used to ensure that local checkpoints are not performed in a cluster where relatively few updates are taking place. In most clusters with high update rates, it is likely that a new local checkpoint is started immediately after the previous one has been completed. The size of all write operations executed since the start of the previous local checkpoints is added. This parameter is also exceptional in that it is specified as the base-2 logarithm of the number of 4-byte words, so that the default value 20 means 4MB (4 x 2^20) of write operations, 21 would mean 8MB, and so on up to a maximum value of 31, which equates to 8GB of write operations. All the write operations in the cluster are added together. Setting `TimeBetweenLocalCheckpoints' to 6 or less means that local checkpoints will be executed continuously without pause, independent of the cluster's workload. * `TimeBetweenGlobalCheckpoints' Options for timebetweenglobalcheckpoints-ndbd *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `2000' *Range* `10-32000' When a transaction is committed, it is committed in main memory in all nodes on which the data is mirrored. However, transaction log records are not flushed to disk as part of the commit. The reasoning behind this behavior is that having the transaction safely committed on at least two autonomous host machines should meet reasonable standards for durability. It is also important to ensure that even the worst of cases--a complete crash of the cluster--is handled properly. To guarantee that this happens, all transactions taking place within a given interval are put into a global checkpoint, which can be thought of as a set of committed transactions that has been flushed to disk. In other words, as part of the commit process, a transaction is placed in a global checkpoint group. Later, this group's log records are flushed to disk, and then the entire group of transactions is safely committed to disk on all computers in the cluster. This parameter defines the interval between global checkpoints. The default is 2000 milliseconds. * `TimeBetweenEpochs' Options for timebetweenepochs-ndbd *Version Introduced* 5.1.22-ndb-6.2.5, 5.1.22-ndb-6.3.2 *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `100' *Range* `0-32000' *Permitted Values * *Type* `numeric' *Default* `100' *Range* `0-32000' This parameter defines the interval between synchronisation epochs for MySQL Cluster Replication. The default value is 100 milliseconds. `TimeBetweenEpochs' is part of the implementation of `micro-GCPs', which can be used to improve the performance of MySQL Cluster Replication. This parameter was introduced in MySQL Cluster NDB 6.2.5 and MySQL Cluster NDB 6.3.2. * `TimeBetweenEpochsTimeout' Options for timebetweenepochstimeout-ndbd *Version Introduced* 5.1.22-ndb-6.2.7, 5.1.22-ndb-6.3.4 *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `4000' *Range* `0-32000' *Permitted Values * *Type* `numeric' *Default* `4000' *Range* `0-32000' *Permitted Values * *Type* `numeric' *Default* `4000' *Range* `0-32000' *Permitted Values * *Type* `numeric' *Default* `4000' *Range* `0-256000' *Permitted Values * *Type* `numeric' *Default* `4000' *Range* `0-32000' *Permitted Values * *Type* `numeric' *Default* `4000' *Range* `0-256000' *Permitted Values * *Type* `numeric' *Default* `0' *Range* `0-256000' This parameter defines a timeout for synchronization epochs for MySQL Cluster Replication. If a node fails to participate in a global checkpoint within the time determined by this parameter, the node is shut down. In MySQL Cluster NDB 7.2.0 and later, the default value is 0; in other words, the timeout is disabled. This represents a change from previous versions of MySQL Cluster, in which the default value was 4000 milliseconds (4 seconds). `TimeBetweenEpochsTimeout' is part of the implementation of `micro-GCPs', which can be used to improve the performance of MySQL Cluster Replication. This parameter was introduced in MySQL Cluster NDB 6.2.7 and MySQL Cluster NDB 6.3.4. The following changes regarding this parameter were made in MySQL Cluster NDB 7.0.21 and MySQL Cluster NDB 7.1.10: * The maximum possible value for this parameter was increased from 32000 milliseconds to 256000 milliseconds. * Setting this parameter to zero now has the effect of disabling GCP stops caused by save timeouts, commit timeouts, or both. * The current value of this parameter and a warning are now written to the cluster log whenever a GCP save takes longer than 1 minute or a GCP save takes longer than 10 seconds. * `MaxBufferedEpochs' Options for maxbufferedepochs-ndbd *Version Introduced* 5.1.23-ndb-6.2.14 *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `100' *Range* `0-100000' The number of unprocessed epochs by which a subscribing node can lag behind. Exceeding this number causes a lagging subscriber to be disconnected. The default value of 100 is sufficient for most normal operations. If a subscribing node does lag enough to cause disconnections, it is usually due to network or scheduling issues with regard to processes or threads. (In rare circumstances, the problem may be due to a bug in the *Note `NDB': mysql-cluster. client.) It may be desirable to set the value lower than the default when epochs are longer. Disconnection prevents client issues from affecting the data node service, running out of memory to buffer data, and eventually shutting down. Instead, only the client is affected as a result of the disconnect (by, for example gap events in the binlog), forcing the client to reconnect or restart the process. * `TimeBetweenInactiveTransactionAbortCheck' Options for timebetweeninactivetransactionabortcheck-ndbd *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `1000' *Range* `1000-4G' Timeout handling is performed by checking a timer on each transaction once for every interval specified by this parameter. Thus, if this parameter is set to 1000 milliseconds, every transaction will be checked for timing out once per second. The default value is 1000 milliseconds (1 second). * `TransactionInactiveTimeout' Options for transactioninactivetimeout-ndbd *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `4G' *Range* `0-4G' This parameter states the maximum time that is permitted to lapse between operations in the same transaction before the transaction is aborted. The default for this parameter is `4G' (also the maximum). For a real-time database that needs to ensure that no transaction keeps locks for too long, this parameter should be set to a relatively small value. The unit is milliseconds. * `TransactionDeadlockDetectionTimeout' Options for transactiondeadlockdetectiontimeout-ndbd *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `1200' *Range* `50-4G' When a node executes a query involving a transaction, the node waits for the other nodes in the cluster to respond before continuing. A failure to respond can occur for any of the following reasons: * The node is `dead' * The operation has entered a lock queue * The node requested to perform the action could be heavily overloaded. This timeout parameter states how long the transaction coordinator waits for query execution by another node before aborting the transaction, and is important for both node failure handling and deadlock detection. In MySQL 5.1.10 and earlier versions, setting it too high could cause undesirable behavior in situations involving deadlocks and node failure. Beginning with MySQL 5.1.11, active transactions occurring during node failures are actively aborted by the MySQL Cluster Transaction Coordinator, and so high settings are no longer an issue with this parameter. The default timeout value is 1200 milliseconds (1.2 seconds). Prior to MySQL Cluster NDB versions 6.2.18, 6.3.24, and 7.0.5, the effective minimum for this parameter was 100 milliseconds. (Bug#44099) Beginning with these versions, the actual minimum is 50 milliseconds. * `DiskSyncSize' Options for disksyncsize-ndbd *Version Introduced* 5.1.12 *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `4M' *Range* `32K-4G' This is the maximum number of bytes to store before flushing data to a local checkpoint file. This is done to prevent write buffering, which can impede performance significantly. This parameter is _not_ intended to take the place of `TimeBetweenLocalCheckpoints'. *Note*: When `ODirect' is enabled, it is not necessary to set `DiskSyncSize'; in fact, in such cases its value is simply ignored. The default value is 4M (4 megabytes). This parameter was added in MySQL 5.1.12. * `DiskCheckpointSpeed' Options for diskcheckpointspeed-ndbd *Version Introduced* 5.1.12 *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `10M' *Range* `1M-4G' The amount of data,in bytes per second, that is sent to disk during a local checkpoint. This allocation is shared by DML operations and backups (but not backup logging), which means that backups started during times of intensive DML may be impaired by flooding of the redo log buffer and may fail altogether if the contention is sufficiently severe. The default value is 10M (10 megabytes per second). This parameter was added in MySQL 5.1.12. * `DiskCheckpointSpeedInRestart' Options for diskcheckpointspeedinrestart-ndbd *Version Introduced* 5.1.12 *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `100M' *Range* `1M-4G' The amount of data,in bytes per second, that is sent to disk during a local checkpoint as part of a restart operation. The default value is 100M (100 megabytes per second). This parameter was added in MySQL 5.1.12. * `NoOfDiskPagesToDiskAfterRestartTUP' Options for noofdiskpagestodiskafterrestarttup-ndbd *Version Removed* 5.1.6 *Restart Type* node *Permitted Values (<= 5.1.6)* *Type* `numeric' *Default* `40' *Range* `1-4G' When executing a local checkpoint, the algorithm flushes all data pages to disk. Merely doing so as quickly as possible without any moderation is likely to impose excessive loads on processors, networks, and disks. To control the write speed, this parameter specifies how many pages per 100 milliseconds are to be written. In this context, a `page' is defined as 8KB. This parameter is specified in units of 80KB per second, so setting `NoOfDiskPagesToDiskAfterRestartTUP' to a value of `20' entails writing 1.6MB in data pages to disk each second during a local checkpoint. This value includes the writing of UNDO log records for data pages. That is, this parameter handles the limitation of writes from data memory. (See the entry for `IndexMemory' for information about index pages.) In short, this parameter specifies how quickly to execute local checkpoints. It operates in conjunction with `NoOfFragmentLogFiles', `DataMemory', and `IndexMemory'. For more information about the interaction between these parameters and possible strategies for choosing appropriate values for them, see *Note mysql-cluster-config-lcp-params::. The default value is 40 (3.2MB of data pages per second). *Note*: This parameter is deprecated as of MySQL 5.1.6. For MySQL 5.1.12 and later versions, use DiskCheckpointSpeed and DiskSyncSize instead. * `NoOfDiskPagesToDiskAfterRestartACC' Options for noofdiskpagestodiskafterrestartacc-ndbd *Version Removed* 5.1.6 *Restart Type* node *Permitted Values (<= 5.1.6)* *Type* `numeric' *Default* `20' *Range* `1-4G' This parameter uses the same units as `NoOfDiskPagesToDiskAfterRestartTUP' and acts in a similar fashion, but limits the speed of writing index pages from index memory. The default value of this parameter is 20 (1.6MB of index memory pages per second). *Note*: This parameter is deprecated as of MySQL 5.1.6. For MySQL 5.1.12 and later versions, use DiskCheckpointSpeed and DiskSyncSize. * `NoOfDiskPagesToDiskDuringRestartTUP' (DEPRECATED) Options for noofdiskpagestodiskduringrestarttup-ndbd *Version Removed* 5.1.6 *Restart Type* node *Permitted Values (<= 5.1.6)* *Type* `numeric' *Default* `40' *Range* `1-4G' This parameter is used in a fashion similar to `NoOfDiskPagesToDiskAfterRestartTUP' and `NoOfDiskPagesToDiskAfterRestartACC', only it does so with regard to local checkpoints executed in the node when a node is restarting. A local checkpoint is always performed as part of all node restarts. During a node restart it is possible to write to disk at a higher speed than at other times, because fewer activities are being performed in the node. This parameter covers pages written from data memory. The default value is 40 (3.2MB per second). *Note*: This parameter is deprecated as of MySQL 5.1.6. For MySQL 5.1.12 and later versions, use `DiskCheckpointSpeedInRestart' and `DiskSyncSize'. * `NoOfDiskPagesToDiskDuringRestartACC' (DEPRECATED) Options for noofdiskpagestodiskduringrestartacc-ndbd *Version Removed* 5.1.6 *Restart Type* node *Permitted Values (<= 5.1.6)* *Type* `numeric' *Default* `20' *Range* `1-4G' Controls the number of index memory pages that can be written to disk during the local checkpoint phase of a node restart. As with `NoOfDiskPagesToDiskAfterRestartTUP' and `NoOfDiskPagesToDiskAfterRestartACC', values for this parameter are expressed in terms of 8KB pages written per 100 milliseconds (80KB/second). The default value is 20 (1.6MB per second). *Note*: This parameter is deprecated as of MySQL 5.1.6. For MySQL 5.1.12 and later versions, use DiskCheckpointSpeedInRestart and DiskSyncSize. * `ArbitrationTimeout' Options for arbitrationtimeout-ndbd *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `3000' *Range* `10-4G' This parameter specifies how long data nodes wait for a response from the arbitrator to an arbitration message. If this is exceeded, the network is assumed to have split. In MySQL Cluster NDB 7.2.0 and later, the default value is 7500 milliseconds (7.5 seconds). Previously, this was 3000 milliseconds (3 seconds). * `Arbitration' Options for arbitration-ndbd *Version Introduced* 5.1.35-ndb-7.0.7 *Restart Type* node *Permitted Values * *Type* `enumeration' *Default* `Default' *Valid Values* `Default' `Disabled' `WaitExternal' The `Arbitration' parameter, added in MySQL Cluster NDB 7.0.7, enables a choice of arbitration schemes, corresponding to one of 3 possible values for this parameter: * `Default' This enables arbitration to proceed normally, as determined by the `ArbitrationRank' settings for the management and API nodes. This is the default value. * `Disabled' Previously, it was possible to disable arbitration only by setting `ArbitrationRank' to 0 on all management and API nodes. Now, you can now use `Arbitration = Disabled' in the `[ndbd default]' section of the `config.ini' file to accomplish this task. In this case, any `ArbitrationRank' settings are ignored. * `WaitExternal' The `Arbitration' parameter also makes it possible to configure arbitration in such a way that the cluster waits until after the time determined by `ArbitrationTimeout' has passed for an external cluster manager application to perform arbitration instead of handling arbitration internally. This can be done by setting `Arbitration = WaitExternal' in the `[ndbd default]' section of the `config.ini' file. For best results with the `WaitExternal' setting, it is recommended that `ArbitrationTimeout' be 2 times as long as the interval required by the external cluster manager to perform arbitration. *Important*: This parameter should be used only in the `[ndbd default]' section of the cluster configuration file. The behavior of the cluster is unspecified when `Arbitration' is set to different values for individual data nodes. Buffering and logging Several `[ndbd]' configuration parameters enable the advanced user to have more control over the resources used by node processes and to adjust various buffer sizes at need. These buffers are used as front ends to the file system when writing log records to disk. If the node is running in diskless mode, these parameters can be set to their minimum values without penalty due to the fact that disk writes are `faked' by the *Note `NDB': mysql-cluster. storage engine's file system abstraction layer. * `UndoIndexBuffer' Options for undoindexbuffer-ndbd *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `2M' *Range* `1M-4G' The UNDO index buffer, whose size is set by this parameter, is used during local checkpoints. The *Note `NDB': mysql-cluster. storage engine uses a recovery scheme based on checkpoint consistency in conjunction with an operational REDO log. To produce a consistent checkpoint without blocking the entire system for writes, UNDO logging is done while performing the local checkpoint. UNDO logging is activated on a single table fragment at a time. This optimization is possible because tables are stored entirely in main memory. The UNDO index buffer is used for the updates on the primary key hash index. Inserts and deletes rearrange the hash index; the NDB storage engine writes UNDO log records that map all physical changes to an index page so that they can be undone at system restart. It also logs all active insert operations for each fragment at the start of a local checkpoint. Reads and updates set lock bits and update a header in the hash index entry. These changes are handled by the page-writing algorithm to ensure that these operations need no UNDO logging. This buffer is 2MB by default. The minimum value is 1MB, which is sufficient for most applications. For applications doing extremely large or numerous inserts and deletes together with large transactions and large primary keys, it may be necessary to increase the size of this buffer. If this buffer is too small, the NDB storage engine issues internal error code 677 (`Index UNDO buffers overloaded'). *Important*: It is not safe to decrease the value of this parameter during a rolling restart. * `UndoDataBuffer' Options for undodatabuffer-ndbd *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `16M' *Range* `1M-4G' This parameter sets the size of the UNDO data buffer, which performs a function similar to that of the UNDO index buffer, except the UNDO data buffer is used with regard to data memory rather than index memory. This buffer is used during the local checkpoint phase of a fragment for inserts, deletes, and updates. Because UNDO log entries tend to grow larger as more operations are logged, this buffer is also larger than its index memory counterpart, with a default value of 16MB. This amount of memory may be unnecessarily large for some applications. In such cases, it is possible to decrease this size to a minimum of 1MB. It is rarely necessary to increase the size of this buffer. If there is such a need, it is a good idea to check whether the disks can actually handle the load caused by database update activity. A lack of sufficient disk space cannot be overcome by increasing the size of this buffer. If this buffer is too small and gets congested, the NDB storage engine issues internal error code 891 (`Data UNDO buffers overloaded'). *Important*: It is not safe to decrease the value of this parameter during a rolling restart. * `RedoBuffer' Options for redobuffer-ndbd *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `8M' *Range* `1M-4G' All update activities also need to be logged. The REDO log makes it possible to replay these updates whenever the system is restarted. The NDB recovery algorithm uses a `fuzzy' checkpoint of the data together with the UNDO log, and then applies the REDO log to play back all changes up to the restoration point. `RedoBuffer' sets the size of the buffer in which the REDO log is written. In MySQL Cluster NDB 6.4.3 and earlier, the default value is 8MB; beginning with MySQL Cluster NDB 7.0.4, the default is 32MB. The minimum value is 1MB. If this buffer is too small, the *Note `NDB': mysql-cluster. storage engine issues error code 1221 (`REDO log buffers overloaded'). For this reason, you should exercise care if you attempt to decrease the value of `RedoBuffer' as part of an online change in the cluster's configuration. Controlling log messages In managing the cluster, it is very important to be able to control the number of log messages sent for various event types to `stdout'. For each event category, there are 16 possible event levels (numbered 0 through 15). Setting event reporting for a given event category to level 15 means all event reports in that category are sent to `stdout'; setting it to 0 means that there will be no event reports made in that category. By default, only the startup message is sent to `stdout', with the remaining event reporting level defaults being set to 0. The reason for this is that these messages are also sent to the management server's cluster log. An analogous set of levels can be set for the management client to determine which event levels to record in the cluster log. * `LogLevelStartup' Options for loglevelstartup-ndbd *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `1' *Range* `0-15' The reporting level for events generated during startup of the process. The default level is 1. * `LogLevelShutdown' Options for loglevelshutdown-ndbd *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `0' *Range* `0-15' The reporting level for events generated as part of graceful shutdown of a node. The default level is 0. * `LogLevelStatistic' Options for loglevelstatistic-ndbd *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `0' *Range* `0-15' The reporting level for statistical events such as number of primary key reads, number of updates, number of inserts, information relating to buffer usage, and so on. The default level is 0. * `LogLevelCheckpoint' Options for loglevelcheckpoint-ndbd *Restart Type* initial, node *Permitted Values * *Type* `numeric' *Default* `0' *Range* `0-15' The reporting level for events generated by local and global checkpoints. The default level is 0. * `LogLevelNodeRestart' Options for loglevelnoderestart-ndbd *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `0' *Range* `0-15' The reporting level for events generated during node restart. The default level is 0. * `LogLevelConnection' Options for loglevelconnection-ndbd *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `0' *Range* `0-15' The reporting level for events generated by connections between cluster nodes. The default level is 0. * `LogLevelError' Options for loglevelerror-ndbd *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `0' *Range* `0-15' The reporting level for events generated by errors and warnings by the cluster as a whole. These errors do not cause any node failure but are still considered worth reporting. The default level is 0. * `LogLevelCongestion' Options for loglevelcongestion-ndbd *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `0' *Range* `0-15' The reporting level for events generated by congestion. These errors do not cause node failure but are still considered worth reporting. The default level is 0. * `LogLevelInfo' Options for loglevelinfo-ndbd *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `0' *Range* `0-15' The reporting level for events generated for information about the general state of the cluster. The default level is 0. * `MemReportFrequency' Options for memreportfrequency-ndbd *Version Introduced* 5.1.14-ndb-6.1.0, 5.1.16 *Restart Type* node *Permitted Values (>= 5.1.16)* *Type* `numeric' *Default* `0' *Range* `0-4G' This parameter controls how often data node memory usage reports are recorded in the cluster log; it is an integer value representing the number of seconds between reports. Each data node's data memory and index memory usage is logged as both a percentage and a number of 32 KB pages of the `DataMemory' and `IndexMemory', respectively, set in the `config.ini' file. For example, if `DataMemory' is equal to 100 MB, and a given data node is using 50 MB for data memory storage, the corresponding line in the cluster log might look like this: 2006-12-24 01:18:16 [MgmSrvr] INFO -- Node 2: Data usage is 50%(1280 32K pages of total 2560) `MemReportFrequency' is not a required parameter. If used, it can be set for all cluster data nodes in the `[ndbd default]' section of `config.ini', and can also be set or overridden for individual data nodes in the corresponding `[ndbd]' sections of the configuration file. The minimum value--which is also the default value--is 0, in which case memory reports are logged only when memory usage reaches certain percentages (80%, 90%, and 100%), as mentioned in the discussion of statistics events in *Note mysql-cluster-log-events::. This parameter was added in MySQL Cluster 5.1.16 and MySQL Cluster NDB 6.1.0. * `StartupStatusReportFrequency' Options for startupstatusreportfrequency-ndbd *Version Introduced* 5.1.30-ndb-6.4.0 *Restart Type* node *Permitted Values * *Type* `numeric' When a data node is started with the `--initial', it initializes the redo log file during Start Phase 4 (see *Note mysql-cluster-start-phases::). When very large values are set for `NoOfFragmentLogFiles', `FragmentLogFileSize', or both, this initialization can take a long time. Previous to MySQL Cluster NDB 6.4.0, only the beginning and end of the redo log file initialization process were logged. Beginning with this version, it is possible to force reports on the progress of this process to be logged periodically, by means of the `StartupStatusReportFrequency' configuration parameter. In this case, progress is reported in the cluster log, in terms of both the number of files and the amount of space that have been initialized, as shown here: 2009-06-20 16:39:23 [MgmSrvr] INFO -- Node 1: Local redo log file initialization status: #Total files: 80, Completed: 60 #Total MBytes: 20480, Completed: 15557 2009-06-20 16:39:23 [MgmSrvr] INFO -- Node 2: Local redo log file initialization status: #Total files: 80, Completed: 60 #Total MBytes: 20480, Completed: 15570 These reports are logged each `StartupStatusReportFrequency' seconds during Start Pahe 4. If `StartupStatusReportFrequency' is 0 (the default), then reports are written to the cluster log only when at the beginning and at the completion of the redo log file initialization process. Debugging Parameters Beginning with MySQL Cluster NDB 6.3.36, MySQL Cluster NDB 7.0.17, and MySQL Cluster NDB 7.1.6, it is possible to cause logging of traces for events generated by creating and dropping tables using `DictTrace'. This parameter is useful only in debugging NDB kernel code. `DictTrace' takes an integer value; currently, 0 (default - no logging) and 1 (logging enabled) are the only supported values. Backup parameters The `[ndbd]' parameters discussed in this section define memory buffers set aside for execution of online backups. * `BackupDataBufferSize' Options for backupdatabuffersize-ndbd *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `2M' *Range* `0-4G' In creating a backup, there are two buffers used for sending data to the disk. The backup data buffer is used to fill in data recorded by scanning a node's tables. Once this buffer has been filled to the level specified as `BackupWriteSize', the pages are sent to disk. While flushing data to disk, the backup process can continue filling this buffer until it runs out of space. When this happens, the backup process pauses the scan and waits until some disk writes have completed freed up memory so that scanning may continue. In MySQL Cluster NDB 6.4.3 and earlier, the default value is 2MB; in MySQL Cluster NDB 7.0.4 and later, it is 16MB. * `BackupLogBufferSize' Options for backuplogbuffersize-ndbd *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `2M' *Range* `0-4G' The backup log buffer fulfills a role similar to that played by the backup data buffer, except that it is used for generating a log of all table writes made during execution of the backup. The same principles apply for writing these pages as with the backup data buffer, except that when there is no more space in the backup log buffer, the backup fails. For that reason, the size of the backup log buffer must be large enough to handle the load caused by write activities while the backup is being made. See *Note mysql-cluster-backup-configuration::. The default value for this parameter should be sufficient for most applications. In fact, it is more likely for a backup failure to be caused by insufficient disk write speed than it is for the backup log buffer to become full. If the disk subsystem is not configured for the write load caused by applications, the cluster is unlikely to be able to perform the desired operations. It is preferable to configure cluster nodes in such a manner that the processor becomes the bottleneck rather than the disks or the network connections. In MySQL Cluster NDB 6.4.3 and earlier, the default value is 2MB; in MySQL Cluster NDB 7.0.4 and later, it is 16MB. * `BackupMemory' Options for backupmemory-ndbd *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `4M' *Range* `0-4G' This parameter is simply the sum of `BackupDataBufferSize' and `BackupLogBufferSize'. In MySQL Cluster NDB 6.4.3 and earlier, the default value was 2MB + 2MB = 4MB; in MySQL Cluster NDB 7.0.4 and later, it is 16MB + 16MB = 32MB. *Important*: If `BackupDataBufferSize' and `BackupLogBufferSize' taken together exceed the default value for `BackupMemory', then this parameter must be set explicitly in the `config.ini' file to their sum. * `BackupReportFrequency' Options for backupreportfrequency-ndbd *Version Introduced* 5.1.19-ndb-6.2.3 *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `0' *Range* `0-4G' This parameter controls how often backup status reports are issued in the management client during a backup, as well as how often such reports are written to the cluster log (provided cluster event logging is configured to permit it--see *Note mysql-cluster-logging-and-checkpointing::). `BackupReportFrequency' represents the time in seconds between backup status reports. The default value is 0. This parameter was added in MySQL Cluster NDB 6.2.3. * `BackupWriteSize' Options for backupwritesize-ndbd *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `32K' *Range* `2K-4G' This parameter specifies the default size of messages written to disk by the backup log and backup data buffers. In MySQL Cluster 6.4.3 and earlier, the default value for this parameter was 32KB; beginning with MySQL Cluster NDB 7.0.4, it is 256KB. * `BackupMaxWriteSize' Options for backupmaxwritesize-ndbd *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `256K' *Range* `2K-4G' This parameter specifies the maximum size of messages written to disk by the backup log and backup data buffers. In MySQL Cluster 6.4.3 and earlier, the default value for this parameter was 256KB; beginning with MySQL Cluster NDB 7.0.4, it is 1MB. *Important*: When specifying these parameters, the following relationships must hold true. Otherwise, the data node will be unable to start. * `BackupDataBufferSize >= BackupWriteSize + 188KB' * `BackupLogBufferSize >= BackupWriteSize + 16KB' * `BackupMaxWriteSize >= BackupWriteSize' * MySQL Cluster Realtime Performance Parameters * The `[ndbd]' parameters discussed in this section are used in scheduling and locking of threads to specific CPUs on multiprocessor data node hosts. They were introduced in MySQL Cluster NDB 6.3.4. *Note*: To make use of these parameters, the data node process must be run as system root. * `LockExecuteThreadToCPU' Options for lockexecutethreadtocpu-ndbd *Version Introduced* 5.1.19-ndb-6.3.4 *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `64K' *Range* `0-64K' Previous to MySQL Cluster NDB 7.0 This parameter specifies the ID of the CPU assigned to handle the *Note `NDBCLUSTER': mysql-cluster. execution thread. The value of this parameter is an integer in the range 0 to 65535 (inclusive). The default is 65535. MySQL Cluster NDB 7.0 and later (beginning with MySQL Cluster NDB 6.4.0) When used with *Note `ndbd': mysql-cluster-programs-ndbd, this parameter (now a string) specifies the ID of the CPU assigned to handle the *Note `NDBCLUSTER': mysql-cluster. execution thread. When used with *Note `ndbmtd': mysql-cluster-programs-ndbmtd, the value of this parameter is a comma-separated list of CPU IDs assigned to handle execution threads. Each CPU ID in the list should be an integer in the range 0 to 65535 (inclusive). The number of IDs specified should match the number of execution threads determined by `MaxNoOfExecutionThreads'. There is no default value. Prior to MySQL Cluster NDB 7.0.18 and MySQL Cluster NDB 7.1.7, the effective maximum value recognized by this parameter as a valid CPU ID was 255; using a greater value caused thread locking to be disabled. (Bug#56185) * `LockMaintThreadsToCPU' Options for lockmaintthreadstocpu-ndbd *Version Introduced* 5.1.19-ndb-6.3.4 *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `64K' *Range* `0-64K' This parameter specifies the ID of the CPU assigned to handle *Note `NDBCLUSTER': mysql-cluster. maintenance threads. The value of this parameter is an integer in the range 0 to 65535 (inclusive). This parameter was added in MySQL Cluster NDB 6.3.4. Prior to MySQL Cluster NDB 6.4.0, the default is 65535; in MySQL Cluster NDB 7.0 and later MySQL Cluster release series, there is no default value. * `RealtimeScheduler' Options for realtimescheduler-ndbd *Version Introduced* 5.1.19-ndb-6.3.4 *Restart Type* node *Permitted Values * *Type* `boolean' *Default* `false' *Range* `-' Setting this parameter to 1 enables real-time scheduling of *Note `NDBCLUSTER': mysql-cluster. threads. The default is 0 (scheduling disabled). * `SchedulerExecutionTimer' Options for schedulerexecutiontimer-ndbd *Version Introduced* 5.1.22-ndb-6.3.4 *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `50' *Range* `0-11000' This parameter specifies the time in microseconds for threads to be executed in the scheduler before being sent. Setting it to 0 minimizes the response time; to achieve higher throughput, you can increase the value at the expense of longer response times. The default is 50 μsec, which our testing shows to increase throughput slightly in high-load cases without materially delaying requests. This parameter was added in MySQL Cluster NDB 6.3.4. * `SchedulerSpinTimer' Options for schedulerspintimer-ndbd *Version Introduced* 5.1.22-ndb-6.3.4 *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `0' *Range* `0-500' This parameter specifies the time in microseconds for threads to be executed in the scheduler before sleeping. The default value is 0. * `BuildIndexThreads' Options for buildindexthreads-ndbd *Version Introduced* 5.1.39-ndb-6.3.30, 5.1.39-ndb-7.0.11 *Restart Type* *Permitted Values * *Type* `numeric' *Default* `0' *Range* `0-128' This parameter determines the number of threads to create when rebuilding indexes during a system or node start. It is supported only when there is more than one fragment for the table per data node (for example, when the `MAX_ROWS' option has been used with *Note `CREATE TABLE': create-table.). Setting this parameter to 0 (which is also the default value) disables multi-threaded building of ordered indexes. The maximum allowed value is 128. This parameter was added in MySQL Cluster NDB 6.3.30 and MySQL Cluster NDB 7.0.11. Prior to MySQL Cluster NDB 7.0.16 and MySQL Cluster NDB 7.1.5, it was supported only when using *Note `ndbd': mysql-cluster-programs-ndbd.; in these and later MySQL Cluster releases, `BuildIndexThreads' is also supported for data nodes running *Note `ndbmtd': mysql-cluster-programs-ndbmtd. (see Bug#54521). Prior to MySQL Cluster NDB 7.1.11, multi-threaded building of ordered indexes was not supported during node initial restarts. Starting with MySQL Cluster NDB 7.1.11, you can enable multi-threaded builds during data node initial restarts by setting the `TwoPassInitialNodeRestartCopy' data node configuration parameter to `TRUE'. * `TwoPassInitialNodeRestartCopy' In MySQL Cluster NDB 7.1.11 and later, multi-threaded building of ordered indexes can be enabled for initial restarts of data nodes by setting this configuration parameter to `TRUE', which enables two-pass copying of data during initial node restarts. You must also set `BuildIndexThreads' to a nonzero value. `Numa' Options for numa-ndbd *Version Introduced* 5.1.51-ndb-7.0.20, 5.1.51-ndb-7.1.9 *Restart Type* node *Permitted Values * *Type* (linux) `boolean' *Default* `0' *Note `NDB': mysql-cluster. is extremely sensitive to Non-Uniform Memory Access settings and multi-CPU systems due to timeouts that it can cause. Due to this fact, and because most MySQL Cluster users do not employ `numactl', support for NUMA is ignored by default by *Note `ndbd': mysql-cluster-programs-ndbd. when running on a Linux system, beginning with MySQL Cluster NDB 7.0.20 and MySQL Cluster 7.1.9. If your Linux system provides NUMA support and you wish for data node memory to be subject to NUMA control, you can set this parameter equal to 0. The `Numa' configuration parameter is supported only on Linux systems where `libnuma.so' is installed. Disk Data Configuration Parameters Configuration parameters affecting Disk Data behavior include the following: * `DiskPageBufferMemory' Options for diskpagebuffermemory-ndbd *Version Introduced* 5.1.6 *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `64M' *Range* `4M-1T' This determines the amount of space used for caching pages on disk, and is set in the `[ndbd]' or `[ndbd default]' section of the `config.ini' file. It is measured in bytes. Each page takes up 32 KB. This means that Cluster Disk Data storage always uses N * 32 KB memory where N is some nonnegative integer. The default value for this parameter is `64M' (2000 pages of 32 KB each). This parameter was added in MySQL 5.1.6. Beginning with MySQL Cluster NDB 7.1.9, you can query the *Note `ndbinfo.diskpagebuffer': mysql-cluster-ndbinfo-diskpagebuffer. table to help determine whether the value for this parameter should be increased to minimize unnecessary disk seeks. See *Note mysql-cluster-ndbinfo-diskpagebuffer::, for more information. * `SharedGlobalMemory' Options for sharedglobalmemory-ndbd *Version Introduced* 5.1.6 *Restart Type* node *Permitted Values (>= 5.1.6)* *Type* `numeric' *Default* `20M' *Range* `0-64T' This parameter determines the amount of memory that is used for log buffers, disk operations (such as page requests and wait queues), and metadata for tablespaces, log file groups, `UNDO' files, and data files. The shared global memory pool also provides memory used for satisfying the memory requirements of the `INITIAL_SIZE' and `UNDO_BUFFER_SIZE' options used with *Note `CREATE LOGFILE GROUP': create-logfile-group. and *Note `ALTER LOGFILE GROUP': alter-logfile-group. statements, including any default value implied for these options by the setting of the `InitialLogFileGroup' data node configuration parameter. `SharedGlobalMemory' can be set in the `[ndbd]' or `[ndbd default]' section of the `config.ini' configuration file, and is measured in bytes. As of MySQL Cluster NDB 7.2.0, the default value is `128M'. (Previously, this was `20M'.) This parameter was added in MySQL 5.1.6. * `DiskIOThreadPool' Options for diskiothreadpool-ndbd *Version Introduced* 5.1.30-ndb-6.4.0 *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `8' *Range* `0-4G' *Permitted Values * *Type* `numeric' *Default* `2' *Range* `0-4G' *Permitted Values * *Type* `numeric' *Default* `2' *Range* `0-4G' This parameter determines the number of unbound threads used for Disk Data file access. Before `DiskIOThreadPool' was introduced, exactly one thread was spawned for each Disk Data file, which could lead to performance issues, particularly when using very large data files. With `DiskIOThreadPool', you can--for example--access a single large data file using several threads working in parallel. Currently, this parameter applies to Disk Data I/O threads only, but we plan in the future to make the number of such threads configurable for in-memory data as well. The optimum value for this parameter depends on your hardware and configuration, and includes these factors: * Physical distribution of Disk Data files You can obtain better performance by placing data files, undo log files, and the data node file system on separate physical disks. If you do this with some or all of these sets of files, then you can set `DiskIOThreadPool' higher to enable separate threads to handle the files on each disk. * Disk performance and types The number of threads that can be accommodated for Disk Data file handling is also dependent on the speed and throughput of the disks. Faster disks and higher throughput allow for more disk I/O threads. Our test results indicate that solid-state disk drives can handle many more disk I/O threads than conventional disks, and thus higher values for `DiskIOThreadPool'. This parameter was added in MySQL Cluster NDB 6.4.0. Previous to MySQL Cluster NDB 6.4.3, it was named `ThreadPool'. Previous to MySQL Cluster NDB 7.0.7, the default value was 8. Beginning with MySQL Cluster NDB 7.0.7 and MySQL Cluster NDB 7.1.0, the default is 2. * Disk Data file system parameters The parameters in the following list were added in MySQL Cluster NDB 6.2.17, 6.3.22, and 6.4.3 to make it possible to place MySQL Cluster Disk Data files in specific directories without the need for using symbolic links. * `FileSystemPathDD' Options for filesystempathdd-ndbd *Version 5.1.32-ndb-6.2.17, Introduced* 5.1.31-ndb-6.3.22, 5.1.32-ndb-6.4.3 *Restart Type* initial, node *Permitted Values * *Type* `file name' *Default* `FileSystemPath' *Range* `-' If this parameter is specified, then MySQL Cluster Disk Data data files and undo log files are placed in the indicated directory. This can be overridden for data files, undo log files, or both, by specifying values for `FileSystemPathDataFiles', `FileSystemPathUndoFiles', or both, as explained for these parameters. It can also be overridden for data files by specifying a path in the `ADD DATAFILE' clause of a *Note `CREATE TABLESPACE': create-tablespace. or *Note `ALTER TABLESPACE': alter-tablespace. statement, and for undo log files by specifying a path in the `ADD UNDOFILE' clause of a *Note `CREATE LOGFILE GROUP': create-logfile-group. or *Note `ALTER LOGFILE GROUP': alter-logfile-group. statement. If `FileSystemPathDD' is not specified, then `FileSystemPath' is used. If a `FileSystemPathDD' directory is specified for a given data node (including the case where the parameter is specified in the `[ndbd default]' section of the `config.ini' file), then starting that data node with `--initial' causes all files in the directory to be deleted. * `FileSystemPathDataFiles' Options for filesystempathdatafiles-ndbd *Version 5.1.32-ndb-6.2.17, Introduced* 5.1.31-ndb-6.3.22, 5.1.32-ndb-6.4.3 *Restart Type* initial, node *Permitted Values * *Type* `file name' *Default* `FileSystemPathDD' *Range* `-' If this parameter is specified, then MySQL Cluster Disk Data data files are placed in the indicated directory. This overrides any value set for `FileSystemPathDD'. This parameter can be overridden for a given data file by specifying a path in the `ADD DATAFILE' clause of a *Note `CREATE TABLESPACE': create-tablespace. or *Note `ALTER TABLESPACE': alter-tablespace. statement used to create that data file. If `FileSystemPathDataFiles' is not specified, then `FileSystemPathDD' is used (or `FileSystemPath', if `FileSystemPathDD' has also not been set). If a `FileSystemPathDataFiles' directory is specified for a given data node (including the case where the parameter is specified in the `[ndbd default]' section of the `config.ini' file), then starting that data node with `--initial' causes all files in the directory to be deleted. * `FileSystemPathUndoFiles' Options for filesystempathundofiles-ndbd *Version 5.1.32-ndb-6.2.17, Introduced* 5.1.31-ndb-6.3.22, 5.1.32-ndb-6.4.3 *Restart Type* initial, node *Permitted Values * *Type* `file name' *Default* `FileSystemPathDD' *Range* `-' If this parameter is specified, then MySQL Cluster Disk Data undo log files are placed in the indicated directory. This overrides any value set for `FileSystemPathDD'. This parameter can be overridden for a given data file by specifying a path in the `ADD UNDO' clause of a *Note `CREATE LOGFILE GROUP': create-logfile-group. or *Note `CREATE LOGFILE GROUP': create-logfile-group. statement used to create that data file. If `FileSystemPathUndoFiles' is not specified, then `FileSystemPathDD' is used (or `FileSystemPath', if `FileSystemPathDD' has also not been set). If a `FileSystemPathUndoFiles' directory is specified for a given data node (including the case where the parameter is specified in the `[ndbd default]' section of the `config.ini' file), then starting that data node with `--initial' causes all files in the directory to be deleted. For more information, see *Note mysql-cluster-disk-data-objects::. * Disk Data object creation parameters The next two parameters enable you--when starting the cluster for the first time--to cause a Disk Data log file group, tablespace, or both, to be created without the use of SQL statements. * `InitialLogFileGroup' Options for initiallogfilegroup-ndbd *Version 5.1.32-ndb-6.2.17, Introduced* 5.1.31-ndb-6.3.22, 5.1.32-ndb-6.4.3 *Restart Type* system *Permitted Values * *Type* `string' *Default* `[see documentation]' *Range* `-' This parameter can be used to specify a log file group that is created when performing an initial start of the cluster. `InitialLogFileGroup' is specified as shown here: InitialLogFileGroup = [name=NAME;] [undo_buffer_size=SIZE;] FILE-SPECIFICATION-LIST FILE-SPECIFICATION-LIST: FILE-SPECIFICATION[; FILE-SPECIFICATION[; ...]] FILE-SPECIFICATION: FILENAME:SIZE The `name' of the log file group is optional and defaults to `DEFAULT-LG'. The `undo_buffer_size' is also optional; if omitted, it defaults to `64M'. Each FILE-SPECIFICATION corresponds to an undo log file, and at least one must be specified in the FILE-SPECIFICATION-LIST. Undo log files are placed according to any values that have been set for `FileSystemPath', `FileSystemPathDD', and `FileSystemPathUndoFiles', just as if they had been created as the result of a *Note `CREATE LOGFILE GROUP': create-logfile-group. or *Note `ALTER LOGFILE GROUP': alter-logfile-group. statement. Consider the following: InitialLogFileGroup = name=LG1; undo_buffer_size=128M; undo1.log:250M; undo2.log:150M This is equivalent to the following SQL statements: CREATE LOGFILE GROUP LG1 ADD UNDOFILE 'undo1.log' INITIAL_SIZE 250M UNDO_BUFFER_SIZE 128M ENGINE NDBCLUSTER; ALTER LOGFILE GROUP LG1 ADD UNDOFILE 'undo2.log' INITIAL_SIZE 150M ENGINE NDBCLUSTER; This logfile group is created when the data nodes are started with `--initial'. Resources for the initial log file group are taken from the global memory pool whose size is determined by the value of the `SharedGlobalMemory' data node configuration parameter; if this parameter is set too low and the values set in `InitialLogFileGroup' for the logfile group's initial size or undo buffer size are too high, the cluster may fail to create the default log file group when starting, or fail to start altogether. This parameter, if used, should always be set in the `[ndbd default]' section of the `config.ini' file. The behavior of a MySQL Cluster when different values are set on different data nodes is not defined. * `InitialTablespace' Options for initialtablespace-ndbd *Version 5.1.32-ndb-6.2.17, Introduced* 5.1.31-ndb-6.3.22, 5.1.32-ndb-6.4.3 *Restart Type* system *Permitted Values * *Type* `string' *Default* `[see documentation]' *Range* `-' This parameter can be used to specify a MySQL Cluster Disk Data tablespace that is created when performing an initial start of the cluster. `InitialTablespace' is specified as shown here: InitialTablespace = [name=NAME;] [extent_size=SIZE;] FILE-SPECIFICATION-LIST The `name' of the tablespace is optional and defaults to `DEFAULT-TS'. The `extent_size' is also optional; it defaults to `1M'. The FILE-SPECIFICATION-LIST uses the same syntax as shown with the `InitialLogfileGroup' parameter, the only difference being that each FILE-SPECIFICATION used with `InitialTablespace' corresponds to a data file. At least one must be specified in the FILE-SPECIFICATION-LIST. Data files are placed according to any values that have been set for `FileSystemPath', `FileSystemPathDD', and `FileSystemPathDataFiles', just as if they had been created as the result of a *Note `CREATE TABLESPACE': create-tablespace. or *Note `ALTER TABLESPACE': alter-tablespace. statement. For example, consider the following line specifying `InitialTablespace' in the `[ndbd default]' section of the `config.ini' file (as with `InitialLogfileGroup', this parameter should always be set in the `[ndbd default]' section, as the behavior of a MySQL Cluster when different values are set on different data nodes is not defined): InitialTablespace = name=TS1; extent_size=8M; data1.dat:2G; data2.dat:4G This is equivalent to the following SQL statements: CREATE TABLESPACE TS1 ADD DATAFILE 'data1.dat' EXTENT_SIZE 8M INITIAL_SIZE 2G ENGINE NDBCLUSTER; ALTER TABLESPACE TS1 ADD UNDOFILE 'data2.dat' INITIAL_SIZE 4G ENGINE NDBCLUSTER; This tablespace is created when the data nodes are started with `--initial', and can be used whenever creating MySQL Cluster Disk Data tables thereafter. Disk Data and `GCP Stop' errors Errors encountered when using Disk Data tables such as `Node NODEID killed this node because GCP stop was detected' (error 2303) are often referred to as `GCP stop errors'. Such errors occur when the redo log is not flushed to disk quickly enough; this is usually due to slow disks and insufficient disk throughput. You can help prevent these errors from occurring by using faster disks, and by placing Disk Data files on a separate disk from the data node file system. Reducing the value of `TimeBetweenGlobalCheckpoints' tends to decrease the amount of data to be written for each global checkpoint, and so may provide some protection against redo log buffer overflows when trying to write a global checkpoint; however, reducing this value also permits less time in which to write the GCP, so this must be done with caution. In addition, adjusting the cluster configuration as discussed here can also help: * MySQL Cluster NDB 6.2 and 6.3 When working with large amounts of data on disk under high load, the default value for `DiskPageBufferMemory' may not be large enough. In such cases, you should increase its value to include most of the memory available to the data nodes after accounting for index memory, data memory, internal buffers, and memory needed by the data node host operating system. You can use this formula as a guide: DiskPageBufferMemory = 0.8 x ( [total memory] - ([operating system memory] + [buffer memory] + DataMemory + IndexMemory) ) Once you have established that sufficient memory is reserved for `DataMemory', `IndexMemory', NDB internal buffers, and operating system overhead, it is possible (and sometimes desirable) to allocate more than the above amount of the remainder to `DiskPageBufferMemory'. * MySQL Cluster NDB 7.X In addition to the considerations given for `DiskPageBufferMemory' as explained previously, it is also very important that the `DiskIOThreadPool' configuration parameter be set correctly; having `DiskIOThreadPool' set too high is very likely to cause GCP stop errors (Bug#37227). GCP stops can be caused by save or commit timeouts; the `TimeBetweenEpochsTimeout' data node configuration parameter determines the timeout for commits. However, beginning with MySQL Cluster NDB 7.0.21 and MySQL Cluster NDB 7.1.10, it is possible to disable both types of timeouts by setting this parameter to 0. Parameters for configuring send buffer memory allocation (MySQL Cluster NDB 7.0 and later) Beginning with MySQL Cluster NDB 6.4.0, send buffer memory is allocated dynamically from a memory pool shared between all transporters, which means that the size of the send buffer can be adjusted as necessary. (Previously, the NDB kernel used a fixed-size send buffer for every node in the cluster, which was allocated when the node started and could not be changed while the node was running.) The following data node configuration parameters were added in MySQL Cluster NDB 6.4.0 to permit the setting of limits on this memory allocation; this change is reflected by the addition of the configuration parameters `TotalSendBufferMemory' and `OverLoadLimit', as well as a change in how the existing `SendBufferMemory' configuration parameter is used. For more information, see *Note mysql-cluster-config-send-buffers::. * `TotalSendBufferMemory' This parameter is available beginning with MySQL Cluster NDB 6.4.0. It is used to determine the total amount of memory to allocate on this node for shared send buffer memory among all configured transporters. If this parameter is set, its minimum permitted value is 256KB; the maxmimum is 4294967039. * `ReservedSendBufferMemory' This parameter is present in *Note `NDBCLUSTER': mysql-cluster. source code beginning with MySQL Cluster NDB 6.4.0. However, it is not currently enabled. For more detailed information about the behavior and use of `TotalSendBufferMemory' and about configuring send buffer memory parameters in MySQL Cluster NDB 6.4.0 and later, see *Note mysql-cluster-config-send-buffers::. *Note*: Previous to MySQL Cluster NDB 7.0, to add new data nodes to a MySQL Cluster, it was necessary to shut down the cluster completely, update the `config.ini' file, and then restart the cluster (that is, you had to perform a system restart). All data node processes had to be started with the `--initial' option. Beginning with MySQL Cluster NDB 7.0, it is possible to add new data node groups to a running cluster online. See *Note mysql-cluster-online-add-node::, for more information. Redo log over-commit handling Beginning with MySQL Cluster NDB 7.1.10, it is possible to control the data node's handling of operations when too much time is taken flushing redo logs to disk. This occurs when a given redo log flush takes longer than `RedoOverCommitLimit' seconds, more than `RedoOverCommitCounter' times, causing any pending transactions to be aborted. When this happens, the API node that sent the transaction can handle the operations that should have been committed either by queuing the operations and re-trying them, or by aborting them, as determined by `DefaultOperationRedoProblemAction'. The data node configuration parameters for setting the timeout and number of times it may be exceeded before the API node takes this action are described in the following list: * `RedoOverCommitCounter' Options for redoovercommitcounter-ndbd *Version Introduced* 5.1.51-ndb-7.1.10 *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `3' *Range* `0-4G' When `RedoOverCommitLimit' is exceeded when trying to write a given redo log to disk this many times or more, any transactions that were not committed as a result are aborted, and an API node where any of these transactions originated handles the operations making up those transactions according to its value for `DefaultOperationRedoProblemAction' (by either queuing the operations to be re-tried, or aborting them). `RedoOverCommitCounter' defaults to 3. Set it to 0 to disable the limit. This parameter was added in MySQL Cluster NDB 7.1.10. * `RedoOverCommitLimit' Options for redoovercommitlimit-ndbd *Version Introduced* 5.1.51-ndb-7.1.10 *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `20' *Range* `0-4G' This parameter sets an upper limit in seconds for trying to write a given redo log to disk before timing out. The number of times the data node tries to flush this redo log, but takes longer than `RedoOverCommitLimit', is kept and compared with `RedoOverCommitCounter', and when flushing takes too long more times than the value of that parameter, any transactions that were not committed as a result of the flush timeout are aborted. When this occurs, the API node where any of these transactions originated handles the operations making up those transactions according to its `DefaultOperationRedoProblemAction' setting (it either queues the operations to be re-tried, or aborts them). By default, `RedoOverCommitLimit' is 20 seconds. Set to 0 to disable checking for redo log flush timeouts. This parameter was added in MySQL Cluster NDB 7.1.10. Controlling restart attempts Beginning in MySQL Cluster NDB 6.2.19, MySQL Cluster NDB 6.3.37, MySQL Cluster NDB 7.0.18, and MySQL Cluster NDB 7.1.7, it is possible to exercise more finely-grained control over restart attempts by data nodes when they fail to start using two data node configuration parameters added in these releases. `MaxStartFailRetries' limits the total number of retries made before giving up on starting the data node; `StartFailRetryDelay' sets the number of seconds between retry attempts, as described in the following list: * `StartFailRetryDelay' Options for startfailretrydelay-ndbd *Version Introduced* 5.1.51-ndb-6.2.19, 5.1.47-ndb-6.3.37, 5.1.47-ndb-7.0.18, 5.1.47-ndb-7.1.7 *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `0' *Range* `0-4G' *Permitted Values * *Type* `numeric' *Default* `0' *Range* `0-4G' *Permitted Values * *Type* `numeric' *Default* `0' *Range* `0-4G' *Permitted Values * *Type* `numeric' *Default* `0' *Range* `0-4G' Beginning in MySQL Cluster NDB 6.2.19, MySQL Cluster NDB 6.3.37, MySQL Cluster NDB 7.0.18, and MySQL Cluster NDB 7.1.7, it is possible to set the number of seconds between restart attempts by the data node in the event on failure on startup. The default is 0 (no delay). *Note*: This parameter is ignored unless `StartOnError' is equal to 0. * `MaxStartFailRetries' Options for maxstartfailretries-ndbd *Version Introduced* 5.1.51-ndb-6.2.19, 5.1.47-ndb-6.3.37, 5.1.47-ndb-7.0.18, 5.1.47-ndb-7.1.7 *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `3' *Range* `0-4G' *Permitted Values * *Type* `numeric' *Default* `3' *Range* `0-4G' *Permitted Values * *Type* `numeric' *Default* `3' *Range* `0-4G' *Permitted Values * *Type* `numeric' *Default* `3' *Range* `0-4G' Beginning in MySQL Cluster NDB 6.2.19, MySQL Cluster NDB 6.3.37, MySQL Cluster NDB 7.0.18, and MySQL Cluster NDB 7.1.7, it is possible to limit the number restart attempts made by the data node in the event that it fails on startup. The default is 3 attempts. *Note*: This parameter is ignored unless `StopOnError' is equal to 0.  File: manual.info, Node: mysql-cluster-api-definition, Next: mysql-cluster-tcp-definition, Prev: mysql-cluster-ndbd-definition, Up: mysql-cluster-config-file 17.3.2.7 Defining SQL and Other API Nodes in a MySQL Cluster ............................................................ The `[mysqld]' and `[api]' sections in the `config.ini' file define the behavior of the MySQL servers (SQL nodes) and other applications (API nodes) used to access cluster data. None of the parameters shown is required. If no computer or host name is provided, any host can use this SQL or API node. Generally speaking, a `[mysqld]' section is used to indicate a MySQL server providing an SQL interface to the cluster, and an `[api]' section is used for applications other than *Note `mysqld': mysqld. processes accessing cluster data, but the two designations are actually synonomous; you can, for instance, list parameters for a MySQL server acting as an SQL node in an `[api]' section. *Note*: For a discussion of MySQL server options for MySQL Cluster, see *Note mysql-cluster-program-options-mysqld::; for information about MySQL server system variables relating to MySQL Cluster, see *Note mysql-cluster-system-variables::. * `Id' Options for id-api *Version Deprecated* 5.1.51-ndb-7.1.9 *Deprecated* 5.1.51-ndb-7.1.9 *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `' *Range* `1-63' The `Id' is an integer value used to identify the node in all cluster internal messages. Prior to MySQL Cluster NDB 6.1.1, the permitted range of values for this parameter was 1 to 63 inclusive. Beginning with MySQL Cluster NDB 6.1.1, the permitted range is 1 to 255 inclusive. This value must be unique for each node in the cluster, regardless of the type of node. *Note*: Data node IDs must be less than 49, regardless of the MySQL Cluster version used. If you plan to deploy a large number of data nodes, it is a good idea to limit the node IDs for API nodes (and management nodes) to values greater than 48. `NodeId' is the preferred parameter name to use when identifying management nodes beginning with MySQL Cluster NDB 6.2.19, MySQL Cluster NDB 6.3.39, MySQL Cluster NDB 7.0.20, and MySQL Cluster NDB 7.1.9. Although `Id' continues to be supported for backward compatibility, it is now deprecated and generates a warning when used. * `NodeId' Options for nodeid-api *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `' *Range* `1-63' The `NodeId' is an integer value used to identify the node in all cluster internal messages. Prior to MySQL Cluster NDB 6.1.1, the permitted range of values for this parameter was 1 to 63 inclusive. Beginning with MySQL Cluster NDB 6.1.1, the permitted range is 1 to 255 inclusive. This value must be unique for each node in the cluster, regardless of the type of node. *Note*: Data node IDs must be less than 49, regardless of the MySQL Cluster version used. If you plan to deploy a large number of data nodes, it is a good idea to limit the node IDs for API nodes (and management nodes) to values greater than 48. `NodeId' is the preferred parameter name to use when identifying management nodes beginning with MySQL Cluster NDB 6.2.19, MySQL Cluster NDB 6.3.39, MySQL Cluster NDB 7.0.20, and MySQL Cluster NDB 7.1.9. Although `Id' continues to be supported for backward compatibility, it is now deprecated and generates a warning when used. * `ExecuteOnComputer' Options for executeoncomputer-api *Restart Type* system *Permitted Values * *Type* `string' *Default* `' *Range* `-' This refers to the `Id' set for one of the computers (hosts) defined in a `[computer]' section of the configuration file. * `HostName' Options for hostname-api *Restart Type* system *Permitted Values * *Type* `string' *Default* `' *Range* `-' Specifying this parameter defines the hostname of the computer on which the SQL node (API node) is to reside. To specify a hostname, either this parameter or `ExecuteOnComputer' is required. If no `HostName' or `ExecuteOnComputer' is specified in a given `[mysql]' or `[api]' section of the `config.ini' file, then an SQL or API node may connect using the corresponding `slot' from any host which can establish a network connection to the management server host machine. _This differs from the default behavior for data nodes, where `localhost' is assumed for `HostName' unless otherwise specified_. * `ArbitrationRank' Options for arbitrationrank-api *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `0' *Range* `0-2' This parameter defines which nodes can act as arbitrators. Both MGM nodes and SQL nodes can be arbitrators. A value of 0 means that the given node is never used as an arbitrator, a value of 1 gives the node high priority as an arbitrator, and a value of 2 gives it low priority. A normal configuration uses the management server as arbitrator, setting its `ArbitrationRank' to 1 (the default for management nodes) and those for all SQL nodes to 0 (the default for SQL nodes). Beginning with MySQL 5.1.16 and MySQL Cluster NDB 6.1.3, it is possible to disable arbitration completely by setting `ArbitrationRank' to 0 on all management and SQL nodes. In MySQL Cluster NDB 7.0.7 and later releases, you can also control arbitration by overriding this parameter; to do this, set the `Arbitration' parameter in the `[ndbd default]' section of the `config.ini' global configuration file. * `ArbitrationDelay' Options for arbitrationdelay-api *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `0' *Range* `0-4G' Setting this parameter to any other value than 0 (the default) means that responses by the arbitrator to arbitration requests will be delayed by the stated number of milliseconds. It is usually not necessary to change this value. * `BatchByteSize' Options for batchbytesize-api *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `32K' *Range* `1024-1M' For queries that are translated into full table scans or range scans on indexes, it is important for best performance to fetch records in properly sized batches. It is possible to set the proper size both in terms of number of records (`BatchSize') and in terms of bytes (`BatchByteSize'). The actual batch size is limited by both parameters. The speed at which queries are performed can vary by more than 40% depending upon how this parameter is set. In future releases, MySQL Server will make educated guesses on how to set parameters relating to batch size, based on the query type. This parameter is measured in bytes and by default is equal to 32KB. * `BatchSize' Options for batchsize-api *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `64' *Range* `1-992' This parameter is measured in number of records and is by default set to 64. The maximum size is 992. * `HeartbeatThreadPriority' Beginning with MySQL Cluster NDB 6.3.32, MySQL Cluster NDB 7.0.13, and MySQL Cluster NDB 7.1.2, it is possible to use this parameter to set the scheduling policy and priority of heartbeat threads for management and API nodes. The syntax for setting this parameter is shown here: HeartbeatThreadPriority = POLICY[, PRIORITY] POLICY: {FIFO | RR} When setting this parameter, you must specify a policy. This is one of `FIFO' (first in, first in) or `RR' (round robin). This followed optionally by the priority (an integer). * `MaxScanBatchSize' Options for maxscanbatchsize-api *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `256K' *Range* `32K-16M' The batch size is the size of each batch sent from each data node. Most scans are performed in parallel to protect the MySQL Server from receiving too much data from many nodes in parallel; this parameter sets a limit to the total batch size over all nodes. The default value of this parameter is set to 256KB. Its maximum size is 16MB. * `TotalSendBufferMemory' Options for totalsendbuffermemory-api *Version Introduced* 5.1.30-ndb-6.4.0 *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `256K' *Range* `0-4G' This parameter is available beginning with MySQL Cluster NDB 6.4.0. It is used to determine the total amount of memory to allocate on this node for shared send buffer memory among all configured transporters. If this parameter is set, its minimum permitted value is 256KB; the maxmimum is 4294967039. For more detailed information about the behavior and use of `TotalSendBufferMemory' and configuring send buffer memory parameters in MySQL Cluster NDB 6.4.0 and later, see *Note mysql-cluster-config-send-buffers::. * `AutoReconnect' Options for autoreconnect-api *Version Introduced* 5.1.35-ndb-6.3.26, 5.1.35-ndb-7.0.7 *Restart Type* node *Permitted Values * *Type* `boolean' *Default* `false' *Range* `false-true' This parameter is available beginning with MySQL Cluster NDB 6.3.26 and MySQL Cluster NDB 7.0.7. By default, its value is `false', which forces disconnected API nodes (including MySQL Servers acting as SQL nodes) the use a new connection to the cluster rather than attempting to re-use an existing one, which can cause problems when using dynamically-allocated node IDs. (Bug#45921) *Note*: This parameter can be overridden using the NDB API. For more information, see `Ndb_cluster_connection::set_auto_reconnect()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndb-cluster-connection-methods.html#ndb-ndb-cluster-connection-set-auto-reconnect), and `Ndb_cluster_connection::get_auto_reconnect()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndb-cluster-connection-methods.html#ndb-ndb-cluster-connection-get-auto-reconnect). * `DefaultOperationRedoProblemAction' Options for defaultoperationredoproblemaction-api *Version Introduced* 5.1.51-ndb-7.1.10 *Restart Type* *Permitted Values * *Type* `enumeration' *Default* `' *Valid Values* `ABORT' `QUEUE' This parameter was introduced in MySQL Cluster NDB 7.1.10 (along with `RedoOverCommitLimit' and `RedoOverCommitCounter') for controlling the data node's handling of operations when too much time is taken flushing redo logs to disk. This occurs when a given redo log flush takes longer than `RedoOverCommitLimit' seconds, more than `RedoOverCommitCounter' times, causing any pending transactions to be aborted. When this happens, the node can respond in either of two ways, according to the value of `DefaultOperationRedoProblemAction', listed here: * `ABORT': Any pending operations from aborted transactions are also aborted. * `QUEUE': Pending operations from transactions that were aborted are queued up to be re-tried. You can obtain some information from a MySQL server running as a Cluster SQL node using *Note `SHOW STATUS': show-status. in the `mysql' client, as shown here: mysql> SHOW STATUS LIKE 'ndb%'; +-----------------------------+---------------+ | Variable_name | Value | +-----------------------------+---------------+ | Ndb_cluster_node_id | 5 | | Ndb_config_from_host | 192.168.0.112 | | Ndb_config_from_port | 1186 | | Ndb_number_of_storage_nodes | 4 | +-----------------------------+---------------+ 4 rows in set (0.02 sec) For information about these Cluster system status variables, see *Note server-status-variables::. *Note*: To add new SQL or API nodes to the configuration of a running MySQL Cluster, it is necessary to perform a rolling restart of all cluster nodes after adding new `[mysqld]' or `[api]' sections to the `config.ini' file (or files, if you are using more than one management server). This must be done before the new SQL or API nodes can connect to the cluster. It is _not_ necessary to perform any restart of the cluster if new SQL or API nodes can employ previously unused API slots in the cluster configuration to connect to the cluster.  File: manual.info, Node: mysql-cluster-tcp-definition, Next: mysql-cluster-tcp-definition-direct, Prev: mysql-cluster-api-definition, Up: mysql-cluster-config-file 17.3.2.8 MySQL Cluster TCP/IP Connections ......................................... TCP/IP is the default transport mechanism for all connections between nodes in a MySQL Cluster. Normally it is not necessary to define TCP/IP connections; MySQL Cluster automatically sets up such connections for all data nodes, management nodes, and SQL or API nodes. *Note*: For an exception to this rule, see *Note mysql-cluster-tcp-definition-direct::. To override the default connection parameters, it is necessary to define a connection using one or more `[tcp]' sections in the `config.ini' file. Each `[tcp]' section explicitly defines a TCP/IP connection between two MySQL Cluster nodes, and must contain at a minimum the parameters `NodeId1' and `NodeId2', as well as any connection parameters to override. It is also possible to change the default values for these parameters by setting them in the `[tcp default]' section. *Important*: Any `[tcp]' sections in the `config.ini' file should be listed _last_, following all other sections in the file. However, this is not required for a `[tcp default]' section. This requirement is a known issue with the way in which the `config.ini' file is read by the MySQL Cluster management server. Connection parameters which can be set in `[tcp]' and `[tcp default]' sections of the `config.ini' file are listed here: * `NodeId1' Options for nodeid1-tcp *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `' *Range* `-' `NodeId2' Options for nodeid2-tcp *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `' *Range* `-' To identify a connection between two nodes it is necessary to provide their node IDs in the `[tcp]' section of the configuration file. These are the same unique `NodeId' (or `Id') values for each of these nodes as described in *Note mysql-cluster-api-definition::. * `HostName1' Options for hostname1-tcp *Restart Type* node *Permitted Values * *Type* `string' *Default* `' *Range* `-' `HostName2' Options for hostname2-tcp *Restart Type* node *Permitted Values * *Type* `string' *Default* `' *Range* `-' The `HostName1' and `HostName2' parameters can be used to specify specific network interfaces to be used for a given TCP connection between two nodes. The values used for these parameters can be hostnames or IP addresses. * `OverloadLimit' Beginning in MySQL Cluster NDB 6.4.0, this parameter can be used to determine the amount of unsent data that must be present in the send buffer before the connection is considered overloaded. See *Note mysql-cluster-config-send-buffers::, for more information. Prior to MySQL Cluster NDB 7.0.27 and MySQL Cluster NDB 7.1.16, the effective value of this parameter was limited by the size of `SendBufferMemory'; beginning with these releases, the actual value for `OverloadLimit' (up to the stated maximum of 4G) is used instead. * `SendBufferMemory' Options for sendbuffermemory-tcp *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `256K' *Range* `64K-4G' TCP transporters use a buffer to store all messages before performing the send call to the operating system. When this buffer reaches 64KB its contents are sent; these are also sent when a round of messages have been executed. To handle temporary overload situations it is also possible to define a bigger send buffer. Prior to MySQL Cluster NDB 7.0, this parameter determines a fixed amount of memory allocated at startup for each configured TCP connection. Beginning with MySQL Cluster NDB 6.4.0, if this parameter is set explicitly, then the memory is not dedicated to each transporter; instead, the value used denotes the hard limit for how much memory (out of the total available memory--that is, `TotalSendBufferMemory') that may be used by a single transporter. For more information about configuring dynamic transporter send buffer memory allocation in MySQL Cluster NDB 7.0 and later, see *Note mysql-cluster-config-send-buffers::. In MySQL Cluster NDB 6.4.3 and earlier, the default size of the send buffer was 256 KB; in MySQL Cluster NDB 7.0.4 and later, it is 2MB, which is the size recommended in most situations. The minimum size is 64 KB; the theoretical maximum is 4 GB. * `SendSignalId' Options for sendsignalid-tcp *Restart Type* node *Permitted Values * *Type* `boolean' *Default* `false (debug builds: true)' *Range* `-' To be able to retrace a distributed message datagram, it is necessary to identify each message. When this parameter is set to `Y', message IDs are transported over the network. This feature is disabled by default in production builds, and enabled in `-debug' builds. * `Checksum' Options for checksum-tcp *Restart Type* node *Permitted Values * *Type* `boolean' *Default* `false' *Range* `-' This parameter is a boolean parameter (enabled by setting it to `Y' or `1', disabled by setting it to `N' or `0'). It is disabled by default. When it is enabled, checksums for all messages are calculated before they placed in the send buffer. This feature ensures that messages are not corrupted while waiting in the send buffer, or by the transport mechanism. * `PortNumber' (_OBSOLETE_) This formerly specified the port number to be used for listening for connections from other nodes. This parameter should no longer be used; use the `ServerPort' data node configuration parameter for this purpose instead. * `ReceiveBufferMemory' Options for receivebuffermemory-tcp *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `64K' *Range* `16K-4G' Specifies the size of the buffer used when receiving data from the TCP/IP socket. In MySQL Cluster NDB 6.4.3 and earlier, the default value of this parameter was 64 KB; beginning with MySQL Cluster NDB 7.0.4, 2MB is the default. The minimum possible value is 16KB; the theoretical maximum is 4GB.  File: manual.info, Node: mysql-cluster-tcp-definition-direct, Next: mysql-cluster-shm-definition, Prev: mysql-cluster-tcp-definition, Up: mysql-cluster-config-file 17.3.2.9 MySQL Cluster TCP/IP Connections Using Direct Connections .................................................................. Setting up a cluster using direct connections between data nodes requires specifying explicitly the crossover IP addresses of the data nodes so connected in the `[tcp]' section of the cluster `config.ini' file. In the following example, we envision a cluster with at least four hosts, one each for a management server, an SQL node, and two data nodes. The cluster as a whole resides on the `172.23.72.*' subnet of a LAN. In addition to the usual network connections, the two data nodes are connected directly using a standard crossover cable, and communicate with one another directly using IP addresses in the `1.1.0.*' address range as shown: # Management Server [ndb_mgmd] Id=1 HostName=172.23.72.20 # SQL Node [mysqld] Id=2 HostName=172.23.72.21 # Data Nodes [ndbd] Id=3 HostName=172.23.72.22 [ndbd] Id=4 HostName=172.23.72.23 # TCP/IP Connections [tcp] NodeId1=3 NodeId2=4 HostName1=1.1.0.1 HostName2=1.1.0.2 The `HostName1' and `HostName2' parameters are used only when specifying direct connections. The use of direct TCP connections between data nodes can improve the cluster's overall efficiency by enabling the data nodes to bypass an Ethernet device such as a switch, hub, or router, thus cutting down on the cluster's latency. It is important to note that to take the best advantage of direct connections in this fashion with more than two data nodes, you must have a direct connection between each data node and every other data node in the same node group.  File: manual.info, Node: mysql-cluster-shm-definition, Next: mysql-cluster-sci-definition, Prev: mysql-cluster-tcp-definition-direct, Up: mysql-cluster-config-file 17.3.2.10 MySQL Cluster Shared-Memory Connections ................................................. MySQL Cluster attempts to use the shared memory transporter and configure it automatically where possible. `[shm]' sections in the `config.ini' file explicitly define shared-memory connections between nodes in the cluster. When explicitly defining shared memory as the connection method, it is necessary to define at least `NodeId1', `NodeId2', and `ShmKey'. All other parameters have default values that should work well in most cases. *Important*: _SHM functionality is considered experimental only_. It is not officially supported in any current MySQL Cluster release, and testing results indicate that SHM performance is not appreciably greater than when using TCP/IP for the transporter. For these reasons, you must determine for yourself or by using our free resources (forums, mailing lists) whether SHM can be made to work correctly in your specific case. * `NodeId1' Options for nodeid1-shm *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `' *Range* `-' `NodeId2' Options for nodeid2-shm *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `' *Range* `-' To identify a connection between two nodes it is necessary to provide node identifiers for each of them, as `NodeId1' and `NodeId2'. * `HostName1' Options for hostname1-shm *Restart Type* node *Permitted Values * *Type* `string' *Default* `' *Range* `-' `HostName2' Options for hostname2-shm *Restart Type* node *Permitted Values * *Type* `string' *Default* `' *Range* `-' The `HostName1' and `HostName2' parameters can be used to specify specific network interfaces to be used for a given SHM connection between two nodes. The values used for these parameters can be hostnames or IP addresses. * `ShmKey' Options for shmkey-shm *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `' *Range* `0-4G' When setting up shared memory segments, a node ID, expressed as an integer, is used to identify uniquely the shared memory segment to use for the communication. There is no default value. * `ShmSize' Options for shmsize-shm *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `1M' *Range* `64K-4G' Each SHM connection has a shared memory segment where messages between nodes are placed by the sender and read by the reader. The size of this segment is defined by `ShmSize'. The default value is 1MB. * `SendSignalId' Options for sendsignalid-shm *Restart Type* node *Permitted Values * *Type* `boolean' *Default* `false' *Range* `-' To retrace the path of a distributed message, it is necessary to provide each message with a unique identifier. Setting this parameter to `Y' causes these message IDs to be transported over the network as well. This feature is disabled by default in production builds, and enabled in `-debug' builds. * `Checksum' Options for checksum-shm *Restart Type* node *Permitted Values * *Type* `boolean' *Default* `true' *Range* `-' This parameter is a boolean (`Y'/`N') parameter which is disabled by default. When it is enabled, checksums for all messages are calculated before being placed in the send buffer. This feature prevents messages from being corrupted while waiting in the send buffer. It also serves as a check against data being corrupted during transport. * `SigNum' Options for signum-shm *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `' *Range* `0-4G' When using the shared memory transporter, a process sends an operating system signal to the other process when there is new data available in the shared memory. Should that signal conflict with with an existing signal, this parameter can be used to change it. This is a possibility when using SHM due to the fact that different operating systems use different signal numbers. The default value of `SigNum' is 0; therefore, it must be set to avoid errors in the cluster log when using the shared memory transporter. Typically, this parameter is set to 10 in the `[shm default]' section of the `config.ini' file.  File: manual.info, Node: mysql-cluster-sci-definition, Next: mysql-cluster-config-lcp-params, Prev: mysql-cluster-shm-definition, Up: mysql-cluster-config-file 17.3.2.11 SCI Transport Connections in MySQL Cluster .................................................... `[sci]' sections in the `config.ini' file explicitly define SCI (Scalable Coherent Interface) connections between cluster nodes. Using SCI transporters in MySQL Cluster is supported only when the MySQL binaries are built using `--with-ndb-sci=/YOUR/PATH/TO/SCI'. The PATH should point to a directory that contains at a minimum `lib' and `include' directories containing SISCI libraries and header files. (See *Note mysql-cluster-interconnects:: for more information about SCI.) In addition, SCI requires specialized hardware. It is strongly recommended to use SCI Transporters only for communication between *Note `ndbd': mysql-cluster-programs-ndbd. processes. Note also that using SCI Transporters means that the *Note `ndbd': mysql-cluster-programs-ndbd. processes never sleep. For this reason, SCI Transporters should be used only on machines having at least two CPUs dedicated for use by *Note `ndbd': mysql-cluster-programs-ndbd. processes. There should be at least one CPU per *Note `ndbd': mysql-cluster-programs-ndbd. process, with at least one CPU left in reserve to handle operating system activities. * `NodeId1' Options for nodeid1-sci *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `' *Range* `-' `NodeId2' Options for nodeid2-sci *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `' *Range* `-' To identify a connection between two nodes it is necessary to provide node identifiers for each of them, as `NodeId1' and `NodeId2'. * `Host1SciId0' Options for host1sciid0-sci *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `' *Range* `0-4G' This identifies the SCI node ID on the first Cluster node (identified by `NodeId1'). * `Host1SciId1' Options for host1sciid1-sci *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `0' *Range* `0-4G' It is possible to set up SCI Transporters for failover between two SCI cards which then should use separate networks between the nodes. This identifies the node ID and the second SCI card to be used on the first node. * `Host2SciId0' Options for host2sciid0-sci *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `' *Range* `0-4G' This identifies the SCI node ID on the second Cluster node (identified by `NodeId2'). * `Host2SciId1' Options for host2sciid1-sci *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `0' *Range* `0-4G' When using two SCI cards to provide failover, this parameter identifies the second SCI card to be used on the second node. * `HostName1' Options for hostname1-sci *Restart Type* node *Permitted Values * *Type* `string' *Default* `' *Range* `-' `HostName2' Options for hostname2-sci *Restart Type* node *Permitted Values * *Type* `string' *Default* `' *Range* `-' The `HostName1' and `HostName2' parameters can be used to specify specific network interfaces to be used for a given SCI connection between two nodes. The values used for these parameters can be hostnames or IP addresses. * `SharedBufferSize' Options for sharedbuffersize-sci *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `10M' *Range* `64K-4G' Each SCI transporter has a shared memory segment used for communication between the two nodes. Setting the size of this segment to the default value of 1MB should be sufficient for most applications. Using a smaller value can lead to problems when performing many parallel inserts; if the shared buffer is too small, this can also result in a crash of the *Note `ndbd': mysql-cluster-programs-ndbd. process. * `SendLimit' Options for sendlimit-sci *Restart Type* node *Permitted Values * *Type* `numeric' *Default* `8K' *Range* `128-32K' A small buffer in front of the SCI media stores messages before transmitting them over the SCI network. By default, this is set to 8KB. Our benchmarks show that performance is best at 64KB but 16KB reaches within a few percent of this, and there was little if any advantage to increasing it beyond 8KB. * `SendSignalId' Options for sendsignalid-sci *Restart Type* node *Permitted Values * *Type* `boolean' *Default* `true' *Range* `-' To trace a distributed message it is necessary to identify each message uniquely. When this parameter is set to `Y', message IDs are transported over the network. This feature is disabled by default in production builds, and enabled in `-debug' builds. * `Checksum' Options for checksum-sci *Restart Type* node *Permitted Values * *Type* `boolean' *Default* `false' *Range* `-' This parameter is a boolean value, and is disabled by default. When `Checksum' is enabled, checksums are calculated for all messages before they are placed in the send buffer. This feature prevents messages from being corrupted while waiting in the send buffer. It also serves as a check against data being corrupted during transport.  File: manual.info, Node: mysql-cluster-config-lcp-params, Next: mysql-cluster-config-send-buffers, Prev: mysql-cluster-sci-definition, Up: mysql-cluster-config-file 17.3.2.12 Configuring MySQL Cluster Parameters for Local Checkpoints .................................................................... The parameters discussed in Logging and Checkpointing and in Data Memory, Index Memory, and String Memory that are used to configure local checkpoints for a MySQL Cluster do not exist in isolation, but rather are very much interdepedent on each other. In this section, we illustrate how these parameters--including `DataMemory', `IndexMemory', `NoOfDiskPagesToDiskAfterRestartTUP', `NoOfDiskPagesToDiskAfterRestartACC', and `NoOfFragmentLogFiles'--relate to one another in a working Cluster. *Important*: The parameters `NoOfDiskPagesToDiskAfterRestartTUP' and `NoOfDiskPagesToDiskAfterRestartACC' were deprecated in MySQL 5.1.6. From MySQL 5.1.6 through 5.1.11, disk writes during LCPs took place at the maximum speed possible. Beginning with MySQL 5.1.12, the speed and throughput for LCPs are controlled using the parameters `DiskSyncSize', `DiskCheckpointSpeed', and `DiskCheckpointSpeedInRestart'. See *Note mysql-cluster-ndbd-definition::. In this example, we assume that our application performs the following numbers of types of operations per hour: * 50000 selects * 15000 inserts * 15000 updates * 15000 deletes We also make the following assumptions about the data used in the application: * We are working with a single table having 40 columns. * Each column can hold up to 32 bytes of data. * A typical *Note `UPDATE': update. run by the application affects the values of 5 columns. * No `NULL' values are inserted by the application. A good starting point is to determine the amount of time that should elapse between local checkpoints (LCPs). It is worth noting that, in the event of a system restart, it takes 40-60 percent of this interval to execute the REDO log--for example, if the time between LCPs is 5 minutes (300 seconds), then it should take 2 to 3 minutes (120 to 180 seconds) for the REDO log to be read. The maximum amount of data per node can be assumed to be the size of the `DataMemory' parameter. In this example, we assume that this is 2 GB. The `NoOfDiskPagesToDiskAfterRestartTUP' parameter represents the amount of data to be checkpointed per unit time--however, this parameter is actually expressed as the number of 8K memory pages to be checkpointed per 100 milliseconds. 2 GB per 300 seconds is approximately 6.8 MB per second, or 700 KB per 100 milliseconds, which works out to roughly 85 pages per 100 milliseconds. Similarly, we can calculate `NoOfDiskPagesToDiskAfterRestartACC' in terms of the time for local checkpoints and the amount of memory required for indexes--that is, the `IndexMemory'. Assuming that we permit 512 MB for indexes, this works out to approximately 20 8-KB pages per 100 milliseconds for this parameter. Next, we need to determine the number of REDO log files required--that is, fragment log files--the corresponding parameter being `NoOfFragmentLogFiles'. We need to make sure that there are sufficient REDO log files for keeping records for at least 3 local checkpoints (in MySQL Cluster NDB 6.3.8 and later, we need only allow for 2 local checkpoints). In a production setting, there are always uncertainties--for instance, we cannot be sure that disks always operate at top speed or with maximum throughput. For this reason, it is best to err on the side of caution, so we double our requirement and calculate a number of fragment log files which should be enough to keep records covering 6 local checkpoints (in MySQL Cluster NDB 6.3.8 and later, a number of fragment log files accommodating 4 local checkpoints should be sufficient). It is also important to remember that the disk also handles writes to the REDO log, so if you find that the amount of data being written to disk as determined by the values of `NoOfDiskPagesToDiskAfterRestartACC' and `NoOfDiskPagesToDiskAfterRestartTUP' is approaching the amount of disk bandwidth available, you may wish to increase the time between local checkpoints. Given 5 minutes (300 seconds) per local checkpoint, this means that we need to support writing log records at maximum speed for 6 * 300 = 1800 seconds (_MySQL Cluster NDB 6.3.8 and later_: 4 * 300 = 1200 seconds). The size of a REDO log record is 72 bytes plus 4 bytes per updated column value plus the maximum size of the updated column, and there is one REDO log record for each table record updated in a transaction, on each node where the data reside. Using the numbers of operations set out previously in this section, we derive the following: * 50000 select operations per hour yields 0 log records (and thus 0 bytes), since *Note `SELECT': select. statements are not recorded in the REDO log. * 15000 *Note `DELETE': delete. statements per hour is approximately 5 delete operations per second. (Since we wish to be conservative in our estimate, we round up here and in the following calculations.) No columns are updated by deletes, so these statements consume only 5 operations * 72 bytes per operation = 360 bytes per second. * 15000 *Note `UPDATE': update. statements per hour is roughly the same as 5 updates per second. Each update uses 72 bytes, plus 4 bytes per column * 5 columns updated, plus 32 bytes per column * 5 columns--this works out to 72 + 20 + 160 = 252 bytes per operation, and multiplying this by 5 operation per second yields 1260 bytes per second. * 15000 *Note `INSERT': insert. statements per hour is equivalent to 5 insert operations per second. Each insert requires REDO log space of 72 bytes, plus 4 bytes per record * 40 columns, plus 32 bytes per column * 40 columns, which is 72 + 160 + 1280 = 1512 bytes per operation. This times 5 operations per second yields 7560 bytes per second. So the total number of REDO log bytes being written per second is approximately 0 + 360 + 1260 + 7560 = 9180 bytes. Multiplied by 1800 seconds, this yields 16524000 bytes required for REDO logging, or approximately 15.75 MB. The unit used for `NoOfFragmentLogFiles' represents a set of 4 16-MB log files--that is, 64 MB. Thus, the minimum value (3) for this parameter is sufficient for the scenario envisioned in this example, since 3 times 64 = 192 MB, or about 12 times what is required; the default value of 8 (or 512 MB) is more than ample in this case.  File: manual.info, Node: mysql-cluster-config-send-buffers, Prev: mysql-cluster-config-lcp-params, Up: mysql-cluster-config-file 17.3.2.13 Configuring MySQL Cluster Send Buffer Parameters .......................................................... Formerly, the NDB kernel used a send buffer whose size was fixed at 2MB for every node in the cluster, which was allocated when the node started. Because the size of this buffer could not be changed after the cluster was started, it was necessary to make it large enough in advance to accommodate the maximum possible load on any transporter socket. However, this was an inefficient use of memory, since much of it often went unused, and could result in large amounts of resources being wasted when scaling up to many API nodes. Beginning with MySQL Cluster NDB 7.0, this problem is solved by employing a unified send buffer whose memory is allocated dynamically from a pool shared by all transporters. This means that the size of the send buffer can be adjusted as necessary. Configuration of the unified send buffer can accomplished by setting the following parameters: * `TotalSendBufferMemory' This parameter can be set for all types of MySQL Cluster nodes--that is, it can be set in the `[ndbd]', `[mgm]', and `[api]' (or `[mysql]') sections of the `config.ini' file. It represents the total amount of memory (in bytes) to be allocated by each node for which it is set for use among all configured transporters. If set, its minimum is 256KB; the maximum is 4294967039. To be backward-compatible with existing configurations, this parameter takes as its default value the sum of the maximum send buffer sizes of all configured transporters, plus an additional 32KB (one page) per transporter. The maximum depends on the type of transporter, as shown in the following table: Transporter Maxmimum Send Buffer Size (bytes) TCP `SendBufferMemory' (default = 2M) SCI `SendLimit' (default = 8K) plus 16K SHM 20K This enables existing configurations to function in close to the same way as they did with MySQL Cluster NDB 6.3 and earlier, with the same amount of memory and send buffer space available to each transporter. However, memory that is unused by one transporter is not available to other transporters. * `OverloadLimit' This parameter is used in the `config.ini' file `[tcp]' section, and denotes the amount of unsent data (in bytes) that must be present in the send buffer before the connection is considered overloaded. When such an overload condition occurs, transactions that affect the overloaded connection fail with NDB API Error 1218 (`Send Buffers overloaded in NDB kernel') until the overload status passes. The default value is 0, in which case the effective overload limit is calculated as `SendBufferMemory * 0.8' for a given connection. The maximum value for this parameter is 4G. * `SendBufferMemory' In MySQL Cluster NDB 6.3 and earlier, this TCP configuration parameter represented the amount of memory allocated at startup for each configured TCP connection. Beginning with MySQL Cluster NDB 7.0, this value denotes a hard limit for the amount of memory that may be used by a single transporter out of the entire pool specified by `TotalSendBufferMemory'. However, the sum of `SendBufferMemory' for all configured transporters may be greater than the `TotalSendBufferMemory' that is set for a given node. This is a way to save memory when many nodes are in use, as long as the maximum amount of memory is never required by all transporters at the same time.  File: manual.info, Node: mysql-cluster-params-overview, Next: mysql-cluster-options-variables, Prev: mysql-cluster-config-file, Up: mysql-cluster-configuration 17.3.3 Overview of MySQL Cluster Configuration Parameters --------------------------------------------------------- * Menu: * mysql-cluster-params-ndbd:: MySQL Cluster Data Node Configuration Parameters * mysql-cluster-params-mgmd:: MySQL Cluster Management Node Configuration Parameters * mysql-cluster-params-api:: MySQL Cluster SQL Node and API Node Configuration Parameters * mysql-cluster-params-other:: Other MySQL Cluster Configuration Parameters The next four sections provide summary tables of MySQL Cluster configuration parameters used in the `config.ini' file to govern the cluster's functioning. Each table lists the parameters for one of the Cluster node process types (*Note `ndbd': mysql-cluster-programs-ndbd, *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd, and *Note `mysqld': mysqld.), and includes the parameter's type as well as its default, mimimum, and maximum values as applicable. These tables also indicate what type of restart is required (node restart or system restart)--and whether the restart must be done with `--initial'--to change the value of a given configuration parameter. When performing a node restart or an initial node restart, all of the cluster's data nodes must be restarted in turn (also referred to as a _rolling restart_). It is possible to update cluster configuration parameters marked as `node' online--that is, without shutting down the cluster--in this fashion. An initial node restart requires restarting each *Note `ndbd': mysql-cluster-programs-ndbd. process with the `--initial' option. A system restart requires a complete shutdown and restart of the entire cluster. An initial system restart requires taking a backup of the cluster, wiping the cluster file system after shutdown, and then restoring from the backup following the restart. In any cluster restart, all of the cluster's management servers must be restarted for them to read the updated configuration parameter values. *Important*: Values for numeric cluster parameters can generally be increased without any problems, although it is advisable to do so progressively, making such adjustments in relatively small increments. Many of these can be increased online, using a rolling restart. However, decreasing the values of such parameters--whether this is done using a node restart, node initial restart, or even a complete system restart of the cluster--is not to be undertaken lightly; it is recommended that you do so only after careful planning and testing. This is especially true with regard to those parameters that relate to memory usage and disk space, such as `MaxNoOfTables', `MaxNoOfOrderedIndexes', and `MaxNoOfUniqueHashIndexes'. In addition, it is the generally the case that configuration parameters relating to memory and disk usage can be raised using a simple node restart, but they require an initial node restart to be lowered. Because some of these parameters can be used for configuring more than one type of cluster node, they may appear in more than one of the tables. *Note*: `4294967039' often appears as a maximum value in these tables. This value is defined in the *Note `NDBCLUSTER': mysql-cluster. sources as `MAX_INT_RNIL' and is equal to `0xFFFFFEFF', or `2^32 - 2^8 - 1'.  File: manual.info, Node: mysql-cluster-params-ndbd, Next: mysql-cluster-params-mgmd, Prev: mysql-cluster-params-overview, Up: mysql-cluster-params-overview 17.3.3.1 MySQL Cluster Data Node Configuration Parameters ......................................................... The summary table in this section provides information about parameters used in the `[ndbd]' or `[ndbd default]' sections of a `config.ini' file for configuring MySQL Cluster data nodes. For detailed descriptions and other additional information about each of these parameters, see *Note mysql-cluster-ndbd-definition::. Beginning with MySQL Cluster NDB 6.4.0, these parameters also apply to *Note `ndbmtd': mysql-cluster-programs-ndbmtd, which is a multi-threaded version of *Note `ndbd': mysql-cluster-programs-ndbd. For more information, see *Note mysql-cluster-programs-ndbmtd::. Restart types Changes in MySQL Cluster configuration parameters do not take effect until the cluster is restarted. The type of restart required to change a given parameter is indicated in the summary table as follows: * `N'--Node restart: The parameter can be updated using a rolling restart (see *Note mysql-cluster-rolling-restart::). * `S'--System restart: The cluster must be shut down completely, then restarted, to effect a change in this parameter. * `I'--Initial restart: Data nodes must be restarted using the `--initial' option. For more information about restart types, see *Note mysql-cluster-params-overview::. *Data Node Configuration Parameters* Name Type/Units Default Min Value Max Value Restart Type Arbitration {Disabled|Default|WaitExternal}Default N ArbitrationTimeoutmilliseconds 3000 10 4G N BackupDataBufferSizebytes 2M 4G N BackupDataDir path FileSystemPath IN BackupLogBufferSizebytes 2M 4G N BackupMaxWriteSizebytes 256K 2K 4G N BackupMemory bytes 4M 4G N BackupReportFrequencyseconds 4G N BackupWriteSizebytes 32K 2K 4G N BatchSizePerLocalScaninteger 64 1 992 N BuildIndexThreads 128 CompressedBackup false N CompressedLCP false N DataDir path . IN DataMemory bytes 80M 1M 1024G N DictTrace bytes undefined 100 N DiskCheckpointSpeedbytes 10M 1M 4G N DiskCheckpointSpeedInRestartbytes 100M 1M 4G N DiskIOThreadPoolthreads 8 4G N Diskless true|false 1 IS (1|0) DiskPageBufferMemorybytes 64M 4M 1T N DiskSyncSize bytes 4M 32K 4G N ExecuteOnComputername S FileSystemPath path DataDir IN FileSystemPathDataFiles FileSystemPathDD IN FileSystemPathDD FileSystemPath IN FileSystemPathUndoFiles FileSystemPathDD IN FragmentLogFileSizebytes 16M 4M 1G IN HeartbeatIntervalDbApimilliseconds 1500 100 4G N HeartbeatIntervalDbDbmilliseconds 1500 10 4G N HeartbeatOrder 65535 S HostName name or IP localhost S address Id unsigned 1 48 N IndexMemory bytes 18M 1M 1T N InitFragmentLogFilessparse|full IN InitialLogFileGroup [see S documentation] InitialNoOfOpenFilesfiles 27 20 4G N InitialTablespace [see S documentation] IOThreadPool threads 8 4G N LockExecuteThreadToCPUCPU ID 64K 64K N LockMaintThreadsToCPUCPU ID 64K 64K N LockPagesInMainMemorytrue|false 1 N (1|0) LogLevelCheckpointlog level 15 IN LogLevelCongestionlevelr 15 N LogLevelConnectioninteger 15 N LogLevelError integer 15 N LogLevelInfo integer 15 N LogLevelNodeRestartinteger 15 N LogLevelShutdowninteger 15 N LogLevelStartupinteger 1 15 N LogLevelStatisticinteger 15 N LongMessageBufferbytes 1M 512K 4G N MaxAllocate unsigned 32M 1M 1G N MaxBufferedEpochsepochs 100 100000 N MaxDMLOperationsPerTransactionoperations 4294967295 32 4294967295 N (DML) MaxLCPStartDelayseconds 600 N MaxNoOfAttributesinteger 1000 32 4G N MaxNoOfConcurrentIndexOperationsinteger 8K 4G N MaxNoOfConcurrentOperationsinteger 32K 32 4G N MaxNoOfConcurrentScansinteger 256 2 500 N MaxNoOfConcurrentSubOperationsunsigned 256 4G N MaxNoOfConcurrentTransactionsinteger 4096 32 4G S MaxNoOfFiredTriggersinteger 4000 4G N MaxNoOfLocalOperationsinteger UNDEFINED 32 4G N MaxNoOfLocalScansinteger UNDEFINED 32 4G N MaxNoOfOpenFilesinteger 40 20 4G N MaxNoOfOrderedIndexesinteger 128 4G N MaxNoOfSavedMessagesinteger 25 4G N MaxNoOfSubscribersunsigned 4G N MaxNoOfSubscriptionsunsigned 4G N MaxNoOfTables integer 128 8 20320 N MaxNoOfTriggersinteger 768 4G N MaxNoOfUniqueHashIndexesinteger 64 4G N MaxParallelScansPerFragmentbytes 32 1 1G N MaxStartFailRetriesunsigned 3 4G N MemReportFrequencyunsigned 4G N NodeGroup 65536 IS NodeId unsigned 1 48 N NoOfDiskPagesToDiskAfterRestartACC8K pages/100 20 1 4G N milliseconds NoOfDiskPagesToDiskAfterRestartTUP8K pages/100 40 1 4G N milliseconds NoOfDiskPagesToDiskDuringRestartACC8K pages/100 20 1 4G N milliseconds NoOfDiskPagesToDiskDuringRestartTUP8K pages/100 40 1 4G N milliseconds NoOfFragmentLogFilesinteger 16 3 4G IN NoOfReplicas integer None 1 4 IS Numa N ODirect boolean 1 N RealtimeScheduler false N RedoBuffer bytes 8M 1M 4G N RedoOverCommitCounter 3 4G N RedoOverCommitLimitseconds 20 4G N ReservedSendBufferMemorybytes 256K 4G N RestartOnErrorInserterror code 2 4 N SchedulerExecutionTimerµsec 50 11000 N SchedulerSpinTimerµsec 500 N ServerPort unsigned 1 64K N SharedGlobalMemorybytes 20M 64T N StartFailRetryDelayunsigned 4G N StartFailureTimeoutmilliseconds 4G N StartNoNodeGroupTimeoutmilliseconds 15000 4294967039 N StartPartialTimeoutmilliseconds 30000 4G N StartPartitionedTimeoutmilliseconds 60000 4G N StartupStatusReportFrequencyseconds N StopOnError true|false true N (1|0) StringMemory % or bytes 5 4G S TcpBind_INADDR_ANY false N TimeBetweenEpochsmilliseconds 100 32000 N TimeBetweenEpochsTimeoutmilliseconds 4000 32000 N TimeBetweenGlobalCheckpointsmilliseconds 2000 10 32000 N TimeBetweenInactiveTransactionAbortCheckmilliseconds 1000 1000 4G N TimeBetweenLocalCheckpointsnumber of 20 31 N 4-byte words, as a base-2 logarithm TimeBetweenWatchDogCheckmilliseconds 6000 70 4G N TimeBetweenWatchDogCheckInitialmilliseconds 6000 70 4G N TotalSendBufferMemorybytes 256K 4G N TransactionBufferMemorybytes 1M 1K 4G N TransactionDeadlockDetectionTimeoutmilliseconds 1200 50 4G N TransactionInactiveTimeoutmilliseconds 4G 4G N TwoPassInitialNodeRestart FALSE N UndoDataBuffer unsigned 16M 1M 4G N UndoIndexBufferunsigned 2M 1M 4G N *Note*: Prior to MySQL Cluster NDB 7.0, to add new data nodes to a MySQL Cluster, it is necessary to shut down the cluster completely, update the `config.ini' file, and then restart the cluster, starting all data node processes using the `--initial' option--that is, you must perform a system restart. Beginning in MySQL Cluster NDB 7.0, it is possible to add new data node groups to a running cluster online. For more information, see *Note mysql-cluster-online-add-node::.  File: manual.info, Node: mysql-cluster-params-mgmd, Next: mysql-cluster-params-api, Prev: mysql-cluster-params-ndbd, Up: mysql-cluster-params-overview 17.3.3.2 MySQL Cluster Management Node Configuration Parameters ............................................................... The summary table in this section provides information about parameters used in the `[ndb_mgmd]' or `[mgm]' sections of a `config.ini' file for configuring MySQL Cluster management nodes. For detailed descriptions and other additional information about each of these parameters, see *Note mysql-cluster-mgm-definition::. Restart types Changes in MySQL Cluster configuration parameters do not take effect until the cluster is restarted. The type of restart required to change a given parameter is indicated in the summary table as follows: * `N'--Node restart: The parameter can be updated using a rolling restart (see *Note mysql-cluster-rolling-restart::). * `S'--System restart: The cluster must be shut down completely, then restarted, to effect a change in this parameter. * `I'--Initial restart: Data nodes must be restarted using the `--initial' option. For more information about restart types, see *Note mysql-cluster-params-overview::. *Management Node Configuration Parameters* Name Type/Units Default Min Value Max Value Restart Type ArbitrationDelaymilliseconds 4G N ArbitrationRank0-2 1 2 N DataDir path . N ExecuteOnComputername S HeartbeatThreadPriority none HostName name or IP S address Id unsigned 1 63 N LogDestination {CONSOLE|SYSLOG|FILE}FILE:filename=ndb_nodeid_cluster.log,maxsize=1000000,maxfiles=6 N MaxNoOfSavedEventsunsigned 100 4G N NodeId unsigned 1 63 N PortNumber unsigned 1186 64K N PortNumberStatsunsigned 64K N wan false N *Note*: After making changes in a management node's configuration, it is necessary to perform a rolling restart of the cluster for the new configuration to take effect. See *Note mysql-cluster-mgm-definition::, for more information. To add new management servers to a running MySQL Cluster, it is also necessary perform a rolling restart of all cluster nodes after modifying any existing `config.ini' files. For more information about issues arising when using multiple management nodes, see *Note mysql-cluster-limitations-multiple-nodes::.  File: manual.info, Node: mysql-cluster-params-api, Next: mysql-cluster-params-other, Prev: mysql-cluster-params-mgmd, Up: mysql-cluster-params-overview 17.3.3.3 MySQL Cluster SQL Node and API Node Configuration Parameters ..................................................................... The summary table in this section provides information about parameters used in the `[mysqld]' and `[api]' sections of a `config.ini' file for configuring MySQL Cluster SQL nodes and API nodes. For detailed descriptions and other additional information about each of these parameters, see *Note mysql-cluster-api-definition::. *Note*: For a discussion of MySQL server options for MySQL Cluster, see *Note mysql-cluster-program-options-mysqld::; for information about MySQL server system variables relating to MySQL Cluster, see *Note mysql-cluster-system-variables::. Restart types Changes in MySQL Cluster configuration parameters do not take effect until the cluster is restarted. The type of restart required to change a given parameter is indicated in the summary table as follows: * `N'--Node restart: The parameter can be updated using a rolling restart (see *Note mysql-cluster-rolling-restart::). * `S'--System restart: The cluster must be shut down completely, then restarted, to effect a change in this parameter. * `I'--Initial restart: Data nodes must be restarted using the `--initial' option. For more information about restart types, see *Note mysql-cluster-params-overview::. *SQL Node/API Node Configuration Parameters* Name Type/Units Default Min Value Max Value Restart Type ArbitrationDelaymilliseconds 4G N ArbitrationRank0-2 2 N AutoReconnect false false true N BatchByteSize bytes 32K 1024 1M N BatchSize records 64 1 992 N ConnectionMap N DefaultOperationRedoProblemAction ExecuteOnComputername S HeartbeatThreadPriority none HostName name or IP S address Id unsigned 1 63 N MaxScanBatchSizebytes 256K 32K 16M N NodeId unsigned 1 63 N TotalSendBufferMemorybytes 256K 4G N wan false N *Note*: To add new SQL or API nodes to the configuration of a running MySQL Cluster, it is necessary to perform a rolling restart of all cluster nodes after adding new `[mysqld]' or `[api]' sections to the `config.ini' file (or files, if you are using more than one management server). This must be done before the new SQL or API nodes can connect to the cluster. It is _not_ necessary to perform any restart of the cluster if new SQL or API nodes can employ previously unused API slots in the cluster configuration to connect to the cluster.  File: manual.info, Node: mysql-cluster-params-other, Prev: mysql-cluster-params-api, Up: mysql-cluster-params-overview 17.3.3.4 Other MySQL Cluster Configuration Parameters ..................................................... The summary tables in this section provide information about parameters used in the `[computer]', `[tcp]', `[shm]', and `[sci]' sections of a `config.ini' file for configuring MySQL Cluster management nodes. For detailed descriptions and other additional information about individual parameters, see *Note mysql-cluster-tcp-definition::, *Note mysql-cluster-shm-definition::, or *Note mysql-cluster-sci-definition::, as appropriate. Restart types Changes in MySQL Cluster configuration parameters do not take effect until the cluster is restarted. The type of restart required to change a given parameter is indicated in the summary tables as follows: * `N'--Node restart: The parameter can be updated using a rolling restart (see *Note mysql-cluster-rolling-restart::). * `S'--System restart: The cluster must be shut down completely, then restarted, to effect a change in this parameter. * `I'--Initial restart: Data nodes must be restarted using the `--initial' option. For more information about restart types, see *Note mysql-cluster-params-overview::. *COMPUTER Configuration Parameters* Name Type/Units Default Min Value Max Value Restart Type HostName name or IP S address Id string IN *TCP Configuration Parameters* Name Type/Units Default Min Value Max Value Restart Type Checksum false N Group unsigned 55 200 N NodeId1 N NodeId2 N NodeIdServer N OverloadLimit bytes 4G N PortNumber unsigned 64K N Proxy N ReceiveBufferMemorybytes 64K 16K 4G N SendBufferMemoryunsigned 256K 64K 4G N SendSignalId false N (debug builds: true) TCP_MAXSEG_SIZEunsigned 2G N TCP_RCV_BUF_SIZEunsigned 70080 1 2G N TCP_SND_BUF_SIZEunsigned 71540 1 2G N TcpBind_INADDR_ANY false N *SHM Configuration Parameters* Name Type/Units Default Min Value Max Value Restart Type Checksum true N Group unsigned 35 200 N NodeId1 N NodeId2 N NodeIdServer N OverloadLimit bytes 4G N PortNumber unsigned 64K N SendSignalId false N ShmKey unsigned 4G N ShmSize bytes 1M 64K 4G N Signum unsigned 4G N *SCI Configuration Parameters* Name Type/Units Default Min Value Max Value Restart Type Checksum false N Group unsigned 15 200 N Host1SciId0 unsigned 4G N Host1SciId1 unsigned 4G N Host2SciId0 unsigned 4G N Host2SciId1 unsigned 4G N NodeId1 N NodeId2 N NodeIdServer N OverloadLimit bytes 4G N PortNumber unsigned 64K N SendLimit unsigned 8K 128 32K N SendSignalId true N SharedBufferSizeunsigned 10M 64K 4G N  File: manual.info, Node: mysql-cluster-options-variables, Next: mysql-cluster-interconnects, Prev: mysql-cluster-params-overview, Up: mysql-cluster-configuration 17.3.4 MySQL Server Options and Variables for MySQL Cluster ----------------------------------------------------------- * Menu: * mysql-cluster-option-tables:: MySQL Cluster Server Option and Variable Reference * mysql-cluster-program-options-mysqld:: `mysqld' Command Options for MySQL Cluster * mysql-cluster-system-variables:: MySQL Cluster System Variables * mysql-cluster-status-variables:: MySQL Cluster Status Variables This section provides information about MySQL server options, server and status variables that are specific to MySQL Cluster. For general information on using these, and for other options and variables not specific to MySQL Cluster, see *Note mysqld-server::. For MySQL Cluster configuration parameters used in the cluster confiuration file (usually named `config.ini'), see *Note mysql-cluster-configuration::.  File: manual.info, Node: mysql-cluster-option-tables, Next: mysql-cluster-program-options-mysqld, Prev: mysql-cluster-options-variables, Up: mysql-cluster-options-variables 17.3.4.1 MySQL Cluster Server Option and Variable Reference ........................................................... The following table provides a list of the command-line options, server and status variables applicable within `mysqld' when it is running as an SQL node in a MySQL Cluster. For a table showing _all_ command-line options, server and status variables available for use with *Note `mysqld': mysqld, see *Note mysqld-option-tables::. *Command Options for MySQL Cluster* Name Cmd-Line Option file System Var Status Var Var Scope Dynamic Handler_discover Yes Both No have_ndbcluster Yes Global No ndb_autoincrement_prefetch_szYes Yes Yes Both Yes ndb-batch-size Yes Yes Yes Global No ndb-blob-read-batch-bytesYes Yes Yes Both Yes ndb-blob-write-batch-bytesYes Yes Yes Both Yes ndb_cache_check_timeYes Yes Yes Global Yes ndb-cluster-connection-poolYes Yes Yes Yes Global No Ndb_cluster_node_id Yes Both No Ndb_config_from_host Yes Both No Ndb_config_from_port Yes Both No Ndb_conflict_fn_max Yes Global No Ndb_conflict_fn_old Yes Global No ndb-connectstringYes Yes ndb_execute_count Yes Global No ndb_extra_loggingYes Yes Yes Global Yes ndb_force_send Yes Yes Yes Both Yes ndb_index_stat_cache_entriesYes Yes ndb_index_stat_enableYes Yes ndb_index_stat_update_freqYes Yes ndb_join_pushdown Yes Global No ndb-log-apply-statusYes Yes Global No - _Variable_: Yes Global No ndb_log_apply_status ndb_log_bin Yes Yes Both Yes ndb_log_binlog_indexYes Yes Global Yes ndb_log_empty_epochsYes Yes Yes Global Yes *Note Yes Global No ndb_log_orig: mysql-cluster-replication-schema. ndb-log-update-as-writeYes Yes Yes Global Yes ndb_log_updated_onlyYes Yes Yes Global Yes ndb-mgmd-host Yes Yes ndb-nodeid Yes Yes Yes Global No Ndb_number_of_data_nodes Yes Global No ndb_optimization_delay Yes Global Yes ndb_optimized_node_selectionYes Yes ndb_pruned_scan_count Yes Global No ndb_pushed_queries_defined Yes Global No ndb_pushed_queries_dropped Yes Global No ndb_pushed_queries_executed Yes Global No ndb_pushed_reads Yes Global No ndb_report_thresh_binlog_epoch_slipYes Yes ndb_report_thresh_binlog_mem_usageYes Yes ndb_scan_count Yes Global No ndb_table_no_logging Yes Session Yes ndb_table_temporary Yes Session Yes ndb_use_copying_alter_table Yes Both No ndb_use_exact_count Yes Both Yes ndb_use_transactionsYes Yes Yes Both Yes ndb-wait-connectedYes Yes Yes Global No ndb-wait-setup Yes Yes Yes Global No ndbcluster Yes Yes - _Variable_: have_ndbcluster ndbinfo_database Yes Global No ndbinfo_max_bytesYes Yes Both Yes ndbinfo_max_rowsYes Yes Both Yes ndbinfo_show_hiddenYes Yes Both Yes ndbinfo_table_prefixYes Yes Both Yes ndbinfo_version Yes Global No server-id-bits Yes Yes Global No - _Variable_: Yes Global No server_id_bits skip-ndbclusterYes Yes slave_allow_batchingYes Yes Yes Global Yes  File: manual.info, Node: mysql-cluster-program-options-mysqld, Next: mysql-cluster-system-variables, Prev: mysql-cluster-option-tables, Up: mysql-cluster-options-variables 17.3.4.2 `mysqld' Command Options for MySQL Cluster ................................................... This section provides descriptions of *Note `mysqld': mysqld. server options relating to MySQL Cluster. For information about *Note `mysqld': mysqld. options not specific to MySQL Cluster, and for general information about the use of options with *Note `mysqld': mysqld, see *Note server-options::. For information about command-line options used with other MySQL Cluster processes (*Note `ndbd': mysql-cluster-programs-ndbd, *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd, and *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm.), see *Note mysql-cluster-program-options-common::. For information about command-line options used with *Note `NDB': mysql-cluster. utility programs (such as *Note `ndb_desc': mysql-cluster-programs-ndb-desc, *Note `ndb_size.pl': mysql-cluster-programs-ndb-size-pl, and *Note `ndb_show_tables': mysql-cluster-programs-ndb-show-tables.), see *Note mysql-cluster-programs::. * `--ndb-batch-size=#' Options for ndb-batch-size *Version Introduced* 5.1.23-ndb-6.3.8 *Command-Line `--ndb-batch-size' Format* *Option-File Format* `ndb-batch-size' *Variable Name* `ndb_batch_size' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `numeric' *Default* `32768' *Range* `0-31536000' This sets the size in bytes that is used for NDB transaction batches. * `--ndb-cluster-connection-pool=#' Options for ndb-cluster-connection-pool *Version Introduced* 5.1.19-ndb-6.2.2 *Command-Line `--ndb-cluster-connection-pool' Format* *Option-File Format* `ndb-cluster-connection-pool' *Variable Name* `ndb_cluster_connection_pool' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `numeric' *Default* `1' *Range* `1-63' By setting this option to a value greater than 1 (the default), a *Note `mysqld': mysqld. process can use multiple connections to the cluster, effectively mimicking several SQL nodes. Each connection requires its own `[api]' or `[mysqld]' section in the cluster configuration (`config.ini') file, and counts against the maximum number of API connections supported by the cluster. Suppose that you have 2 cluster host computers, each running an SQL node whose *Note `mysqld': mysqld. process was started with `--ndb-cluster-connection-pool=4'; this means that the cluster must have 8 API slots available for these connections (instead of 2). All of these connections are set up when the SQL node connects to the cluster, and are allocated to threads in a round-robin fashion. This option is useful only when running *Note `mysqld': mysqld. on host machines having multiple CPUs, multiple cores, or both. For best results, the value should be smaller than the total number of cores available on the host machine. Setting it to a value greater than this is likely to degrade performance severely. *Important*: Because each SQL node using connection pooling occupies multiple API node slots--each slot having its own node ID in the cluster--you must _not_ use a node ID as part of the cluster connectstring when starting any *Note `mysqld': mysqld. process that employs connection pooling. Setting a node ID in the connectstring when using the `--ndb-cluster-connection-pool' option causes node ID allocation errors when the SQL node attempts to connect to the cluster. This option was introduced in MySQL Cluster NDB 6.2.2. Beginning with MySQL Cluster NDB 6.2.16 and MySQL Cluster NDB 6.3.13, the value used for this option is available as a system variable (Bug#35573). Prior to MySQL Cluster NDB 7.0.23 and MySQL Cluster NDB 7.1.12, there was also a status variable corresponding to this option; however, the status variable was removed as redundant as of these versions. (Bug#60119) * `--ndb-blob-read-batch-bytes=BYTES' Options for ndb-blob-read-batch-bytes *Version Introduced* 5.1.51-ndb-7.0.21, 5.1.51-ndb-7.1.10 *Command-Line `--ndb-blob-read-batch-bytes' Format* *Option-File Format* `ndb-blob-read-batch-bytes' *Variable Name* `ndb_blob_read_batch_bytes' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `numeric' *Default* `65535' *Range* `0-4294967295' This option can be used to set the size (in bytes) for batching of *Note `BLOB': blob. data reads in MySQL Cluster applications. When this batch size is exceeded by the amount of *Note `BLOB': blob. data to be read within the current transaction, any pending *Note `BLOB': blob. read operations are immediately executed. The maximum value for this option is 4294967295; the default is 65535. Setting it to 0 has the effect of disabling *Note `BLOB': blob. read batching. *Note*: In NDB API applications, you can control *Note `BLOB': blob. write batching with the `setMaxPendingBlobReadBytes()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndbtransaction-methods.html#ndb-ndbtransaction-setmaxpendingblobreadbytes) and `getMaxPendingBlobReadBytes()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndbtransaction-methods.html#ndb-ndbtransaction-getmaxpendingblobreadbytes) methods. This option was introduced in MySQL Cluster NDB 7.0.21 and MySQL Cluster NDB 7.1.10. * `--ndb-blob-write-batch-bytes=BYTES' Options for ndb-blob-write-batch-bytes *Version Introduced* 5.1.51-ndb-7.0.21, 5.1.51-ndb-7.1.10 *Command-Line `--ndb-blob-write-batch-bytes' Format* *Option-File Format* `ndb-blob-write-batch-bytes' *Variable Name* `ndb_blob_write_batch_bytes' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `numeric' *Default* `65535' *Range* `0-4294967295' This option can be used to set the size (in bytes) for batching of *Note `BLOB': blob. data writes in MySQL Cluster applications. When this batch size is exceeded by the amount of *Note `BLOB': blob. data to be written within the current transaction, any pending *Note `BLOB': blob. write operations are immediately executed. The maximum value for this option is 4294967295; the default is 65535. Setting it to 0 has the effect of disabling *Note `BLOB': blob. write batching. *Note*: In NDB API applications, you can control *Note `BLOB': blob. write batching with the `setMaxPendingBlobWriteBytes()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndbtransaction-methods.html#ndb-ndbtransaction-setmaxpendingblobwritebytes) and `getMaxPendingBlobWriteBytes()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndbtransaction-methods.html#ndb-ndbtransaction-getmaxpendingblobwritebytes) methods. This option was introduced in MySQL Cluster NDB 7.0.21 and MySQL Cluster NDB 7.1.10. * `--ndb-connectstring=CONNECT_STRING' Options for ndb-connectstring *Command-Line `--ndb-connectstring' Format* *Option-File Format* `ndb-connectstring' *Permitted Values * *Type* `string' When using the *Note `NDBCLUSTER': mysql-cluster. storage engine, this option specifies the management server that distributes cluster configuration data. See *Note mysql-cluster-connectstring::, for syntax. * `--ndbcluster' Options for ndbcluster *Command-Line `--ndbcluster' Format* *Option-File Format* `ndbcluster' *Option Sets Yes, Variable* `have_ndbcluster' *Disabled by* `skip-ndbcluster' *Permitted Values * *Type* `boolean' *Default* `FALSE' The *Note `NDBCLUSTER': mysql-cluster. storage engine is necessary for using MySQL Cluster. If a *Note `mysqld': mysqld. binary includes support for the *Note `NDBCLUSTER': mysql-cluster. storage engine, the engine is disabled by default. Use the `--ndbcluster' option to enable it. Use `--skip-ndbcluster' to explicitly disable the engine. * `--ndb-log-apply-status' Options for ndb-log-apply-status *Version Introduced* 5.1.51-ndb-7.0.21, 5.1.51-ndb-7.1.10 *Command-Line `--ndb-log-apply-status' Format* *Option-File Format* `ndb-log-apply-status' *Option Sets Yes, Variable* `ndb_log_apply_status' *Variable Name* `ndb_log_apply_status' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `boolean' *Default* `ON' Causes a slave *Note `mysqld': mysqld. to log any updates received from its immediate master to the `mysql.ndb_apply_status' table in its own binary log using its own server ID rather than the server ID of the master. In a circular or chain replication setting, this allows such updates to propagate to the `mysql.ndb_apply_status' tables of any MySQL servers configured as slaves of the current *Note `mysqld': mysqld. In a chain replication setup, using this option allows downstream (slave) clusters to be aware of their positions relative to all of their upstream contributors (masters). In a circular replication setup, this option causes changes to `ndb_apply_status' tables to complete the entire circuit, eventually propagating back to the originating MySQL Cluster. This also allows a cluster acting as a master to see when its changes (epochs) have been applied to the other clusters in the circle. This option was added in MySQL Cluster NDB 7.0.21 and MySQL Cluster NDB 7.1.10. It has no effect unless the MySQL server is started with the `--ndbcluster' option. * `--ndb-nodeid=#' Options for ndb-nodeid *Version Introduced* 5.1.15 *Command-Line `--ndb-nodeid=#' Format* *Option-File Format* `ndb-nodeid' *Variable Name* `Ndb_cluster_node_id' *Variable Scope* Global *Dynamic Variable* No *Permitted Values (>= 5.1.5)* *Type* `numeric' *Range* `1-255' Set this MySQL server's node ID in a MySQL Cluster. Prior to MySQL Cluster NDB 7.0.15 and MySQL Cluster NDB 7.1.4, this option can be used _instead_ of specifying the node ID as part of the connectstring or in the `config.ini' file, or permitting the cluster to determine an arbitrary node ID. If you use this option, then `--ndb-nodeid' must be specified _before_ `--ndb-connectstring'. If `--ndb-nodeid' is used _and_ a node ID is specified in the connectstring, then the MySQL server cannot connect to the cluster. Beginning with MySQL Cluster NDB 7.0.15 and MySQL Cluster NDB 7.1.4, the `--ndb-nodeid' option _overrides_ any node ID set with `--ndb-connectstring', regardless of the order in which the two options are used. In addition (regardless of the MySQL Cluster version), if `--ndb-nodeid' is used, then either a matching node ID must be found in a `[mysqld]' or `[api]' section of `config.ini', or there must be an `open' `[mysqld]' or `[api]' section in the file (that is, a section without a `NodeId' or `Id' parameter specified). This is also true if the node ID is specified as part of the connectstring. Regardless of how the node ID is determined, its is shown as the value of the global status variable `Ndb_cluster_node_id' in the output of *Note `SHOW STATUS': show-status, and as `cluster_node_id' in the `connection' row of the output of *Note `SHOW ENGINE NDBCLUSTER STATUS': show-engine. For more information about node IDs for MySQL Cluster SQL nodes, see *Note mysql-cluster-api-definition::. * `--server-id-bits=#' Options for server-id-bits *Version Introduced* 5.1.47-ndb-7.0.17, 5.1.47-ndb-7.1.6 *Command-Line `--server-id-bits=#' Format* *Option-File Format* `server-id-bits' *Option Sets Yes, Variable* `server_id_bits' *Variable Name* `server_id_bits' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `numeric' *Default* `32' *Range* `7-32' This option indicates the number of least significant bits within the 32-bit `server_id' which actually identify the server. Indicating that the server is actually identified by fewer than 32 bits makes it possible for some of the remaining bits to be used for other purposes, such as storing user data generated by applications using the NDB API's Event API within the `AnyValue' of an `OperationOptions' structure (MySQL Cluster uses the `AnyValue' to store the server ID). When extracting the effective server ID from `server_id' for purposes such as detection of replication loops, the server ignores the remaining bits. The `--server-id-bits' option is used to mask out any irrelevant bits of `server_id' in the IO and SQL threads when deciding whether an event should be ignored based on the server ID. This data can be read from the binary log by *Note `mysqlbinlog': mysqlbinlog, provided that it is run with its own `--server-id-bits' option set to 32 (the default). The value of `server_id' must be less than 2 ^ `server_id_bits'; otherwise, *Note `mysqld': mysqld. refuses to start. This system variable was added in MySQL Cluster NDB 7.0.17 and MySQL Cluster NDB 7.1.6; it is supported only in these and later releases of MySQL Cluster. It is not supported by the standard MySQL Server. * `--skip-ndbcluster' Options for skip-ndbcluster *Command-Line `--skip-ndbcluster' Format* *Option-File Format* `skip-ndbcluster' Disable the *Note `NDBCLUSTER': mysql-cluster. storage engine. This is the default for binaries that were built with *Note `NDBCLUSTER': mysql-cluster. storage engine support; the server allocates memory and other resources for this storage engine only if the `--ndbcluster' option is given explicitly. See *Note mysql-cluster-quick::, for an example. * `--ndb-wait-connected=SECONDS' Options for ndb-wait-connected *Version Introduced* 5.1.16-ndb-6.2.0 *Command-Line `--ndb-wait-connected=#' Format* *Option-File Format* `ndb-wait-connected' *Variable Name* `ndb-wait-connected' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `numeric' *Default* `0' *Range* `0-31536000' This option sets the period of time that the MySQL server waits for connections to MySQL Cluster management and data nodes to be established before accepting MySQL client connections. The time is specified in seconds. The default value is `0'. * `--ndb-wait-setup=SECONDS' Options for ndb-wait-setup *Version Introduced* 5.1.39-ndb-6.2.19, 5.1.39-ndb-6.3.28, 5.1.39-ndb-7.0.9 *Command-Line `--ndb-wait-setup=#' Format* *Option-File Format* `ndb-wait-setup' *Variable Name* `ndb-wait-setup' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `numeric' *Default* `15' *Range* `0-31536000' This variable shows the period of time that the MySQL server waits for the *Note `NDB': mysql-cluster. storage engine to complete setup before timing out and treating *Note `NDB': mysql-cluster. as unavailable. The time is specified in seconds. The default value is `15'.  File: manual.info, Node: mysql-cluster-system-variables, Next: mysql-cluster-status-variables, Prev: mysql-cluster-program-options-mysqld, Up: mysql-cluster-options-variables 17.3.4.3 MySQL Cluster System Variables ....................................... This section provides detailed information about MySQL server system variables that are specific to MySQL Cluster and the *Note `NDB': mysql-cluster. storage engine. For system variables not specific to MySQL Cluster, see *Note server-system-variables::. For general information on using system variables, see *Note using-system-variables::. * `have_ndbcluster' Options for have_ndbcluster *Variable Name* `have_ndbcluster' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `boolean' `YES' if *Note `mysqld': mysqld. supports *Note `NDBCLUSTER': mysql-cluster. tables. `DISABLED' if `--skip-ndbcluster' is used. This variable is deprecated and is removed in MySQL 5.6. Use *Note `SHOW ENGINES': show-engines. instead. * `multi_range_count' Options for multi_range_count *Command-Line `--multi_range_count=#' Format* *Option-File Format* `multi_range_count' *Option Sets Yes, Variable* `multi_range_count' *Variable Name* `multi_range_count' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `numeric' *Default* `256' *Range* `1-4294967295' The maximum number of ranges to send to a table handler at once during range selects. The default value is 256. Sending multiple ranges to a handler at once can improve the performance of certain selects dramatically. This is especially true for the *Note `NDBCLUSTER': mysql-cluster. table handler, which needs to send the range requests to all nodes. Sending a batch of those requests at once reduces communication costs significantly. This variable is deprecated in MySQL 5.1, and is no longer supported in MySQL 5.5, in which arbitrarily long lists of ranges can be processed. * `ndb_autoincrement_prefetch_sz' Options for ndb_autoincrement_prefetch_sz *Command-Line `--ndb_autoincrement_prefetch_sz' Format* *Option-File Format* `ndb_autoincrement_prefetch_sz' *Option Sets Yes, Variable* `ndb_autoincrement_prefetch_sz' *Variable Name* `ndb_autoincrement_prefetch_sz' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values (<= 5.1.22)* *Type* `numeric' *Default* `32' *Range* `1-256' *Permitted Values (>= 5.1.23)* *Type* `numeric' *Default* `1' *Range* `1-256' Determines the probability of gaps in an autoincremented column. Set it to `1' to minimize this. Setting it to a high value for optimization--makes inserts faster, but decreases the likelihood that consecutive autoincrement numbers will be used in a batch of inserts. Default value: `32'. Minimum value: `1'. Beginning with MySQL Cluster NDB 6.2.10, MySQL Cluster NDB 6.3.7, and MySQL 5.1.23, this variable affects the number of `AUTO_INCREMENT' IDs that are fetched between statements only. Within a statement, at least 32 IDs are now obtained at a time. The default value for `ndb_autoincrement_prefetch_sz' is now `1', to increase the speed of statements inserting single rows. (Bug#31956) Beginning with MySQL Cluster NDB 6.3.31 and MySQL CLuster NDB 7.0.11, the maximum value for `ndb_autoincrement_prefetch_sz' is increased, from 256 to 65536. (Bug#50621) * `ndb_cache_check_time' Options for ndb_cache_check_time *Command-Line `--ndb_cache_check_time' Format* *Option-File Format* `ndb_cache_check_time' *Option Sets Yes, Variable* `ndb_cache_check_time' *Variable Name* `ndb_cache_check_time' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `numeric' *Default* `0' The number of milliseconds that elapse between checks of MySQL Cluster SQL nodes by the MySQL query cache. Setting this to 0 (the default and minimum value) means that the query cache checks for validation on every query. The recommended maximum value for this variable is 1000, which means that the check is performed once per second. A larger value means that the check is performed and possibly invalidated due to updates on different SQL nodes less often. It is generally not desirable to set this to a value greater than 2000. * `ndb_extra_logging' Options for ndb_extra_logging *Version Introduced* 5.1.6 *Command-Line `ndb_extra_logging=#' Format* *Option-File Format* `ndb_extra_logging' *Variable Name* `ndb_extra_logging' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `numeric' *Default* `0' This variable can be used to enable recording in the MySQL error log of information specific to the *Note `NDB': mysql-cluster. storage engine. It is normally of interest only when debugging *Note `NDB': mysql-cluster. storage engine code. The default value is 0, which means that the only *Note `NDB': mysql-cluster.-specific information written to the MySQL error log relates to transaction handling. If the value is greater than 0 but less than 10, *Note `NDB': mysql-cluster. table schema and connection events are also logged, as well as whether or not conflict resolution is in use, and other *Note `NDB': mysql-cluster. errors and information. If the value is set to 10 or more, information about *Note `NDB': mysql-cluster. internals, such as the progress of data distribution among cluster nodes, is also written to the MySQL error log. This variable was added in MySQL 5.1.6. * `ndb_force_send' Options for ndb_force_send *Command-Line `--ndb-force-send' Format* *Option-File Format* `ndb_force_send' *Option Sets Yes, Variable* `ndb_force_send' *Variable Name* `ndb_force_send' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `boolean' *Default* `TRUE' Forces sending of buffers to *Note `NDB': mysql-cluster. immediately, without waiting for other threads. Defaults to `ON'. * `ndb_index_stat_cache_entries' Options for ndb_index_stat_cache_entries *Version Removed* 5.1.14 *Command-Line `--ndb_index_stat_cache_entries' Format* *Option-File Format* `ndb_index_stat_cache_entries' *Permitted Values * *Type* `numeric' *Default* `32' *Range* `0-4294967295' Sets the granularity of the statistics by determining the number of starting and ending keys to store in the statistics memory cache. Zero means no caching takes place; in this case, the data nodes are always queried directly. Default value: `32'. *Note*: If `ndb_index_stat_enable' is `OFF', then setting this variable has no effect. * `ndb_index_stat_enable' Options for ndb_index_stat_enable *Version Removed* 5.1.19 *Command-Line `--ndb_index_stat_enable' Format* *Option-File Format* `ndb_index_stat_enable' *Permitted Values * *Type* `boolean' *Default* `OFF' Use *Note `NDB': mysql-cluster. index statistics in query optimization. Defaults to `ON'. * `ndb_index_stat_update_freq' Options for ndb_index_stat_update_freq *Version Removed* 5.1.14 *Command-Line `--ndb_index_stat_update_freq' Format* *Option-File Format* `ndb_index_stat_update_freq' *Permitted Values * *Type* `numeric' *Default* `20' *Range* `0-4294967295' How often to query data nodes instead of the statistics cache. For example, a value of `20' (the default) means to direct every 20^th query to the data nodes. *Note*: If `ndb_index_stat_cache_entries' is `0', then setting this variable has no effect; in this case, every query is sent directly to the data nodes. * `ndb_join_pushdown' Options for ndb_join_pushdown *Version Introduced* 5.1.51-ndb-7.2.0 *Variable Name* `ndb_join_pushdown' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `boolean' *Default* `TRUE' Added in MySQL Cluster NDB 7.2.0, this variable controls whether joins on *Note `NDB': mysql-cluster. tables are pushed down to the NDB kernel (data nodes). Previously, a join was handled using multiple accesses of *Note `NDB': mysql-cluster. by the SQL node; however, when `ndb_join_pushdown' is enabled, a pushable join is sent in its entirety to the data nodes, where it can be distributed among the data nodes and executed in parallel on multiple copies of the data, with a single, merged result being returned to *Note `mysqld': mysqld. This can reduce greatly the number of round trips between an SQL node and the data nodes required to handle such a join. By default, `ndb_join_pushdown' is enabled. In order for a join to be pushable, it must meet the following conditions: * Any columns to be joined must use _exactly_ the same data type. (For example, if an *Note `INT': numeric-types. and a *Note `BIGINT': numeric-types. column are joined, the join cannot be pushed down.) * Queries referencing *Note `BLOB': blob. or *Note `TEXT': blob. columns are not supported. * Explicit locking is not supported; however, the *Note `NDB': mysql-cluster. storage engine's characteristic implicit row-based locking is enforced. This means that a join using `FOR UPDATE' cannot be pushed down. * In order for a join to be pushed down, child tables in the join must be accessed using one of the `ref', `eq_ref', or `const' access methods, or some combination of these methods. * Joins referencing tables explicitly partitioned by `[LINEAR] HASH', `LIST', or `RANGE' currently cannot be pushed down. You can see whether a given join can be pushed down by checking it with *Note `EXPLAIN': explain.; when the join can be pushed down, you can see references to the `pushed join' in the `Extra' column of the output, as shown in this example: mysql> EXPLAIN -> SELECT e.first_name, e.last_name, t.title, d.dept_name -> FROM employees e -> JOIN dept_emp de ON e.emp_no=de.emp_no -> JOIN departments d ON d.dept_no=de.dept_no -> JOIN titles t ON e.emp_no=t.emp_no\G *************************** 1. row *************************** id: 1 select_type: SIMPLE table: d type: ALL possible_keys: PRIMARY key: NULL key_len: NULL ref: NULL rows: 9 Extra: Parent of 4 pushed join@1 *************************** 2. row *************************** id: 1 select_type: SIMPLE table: de type: ref possible_keys: PRIMARY,emp_no,dept_no key: dept_no key_len: 4 ref: employees.d.dept_no rows: 5305 Extra: Child of 'd' in pushed join@1 *************************** 3. row *************************** id: 1 select_type: SIMPLE table: e type: eq_ref possible_keys: PRIMARY key: PRIMARY key_len: 4 ref: employees.de.emp_no rows: 1 Extra: Child of 'de' in pushed join@1 *************************** 4. row *************************** id: 1 select_type: SIMPLE table: t type: ref possible_keys: PRIMARY,emp_no key: emp_no key_len: 4 ref: employees.de.emp_no rows: 19 Extra: Child of 'e' in pushed join@1 4 rows in set (0.00 sec) Two additional sources of information about pushed join performance are available: 1. The status variables `Ndb_pushed_queries_defined', `Ndb_pushed_queries_dropped', `Ndb_pushed_queries_executed', and `Ndb_pushed_reads' (all introduced in MySQL Cluster NDB 7.2.0). 2. The counters in the *Note `ndbinfo.counters': mysql-cluster-ndbinfo-counters. table that belong to the `DBSPJ' kernel block. (These counters and the `DBSPJ' block were also introduced in MySQL Cluster NDB 7.2.0). See *Note mysql-cluster-ndbinfo-counters::, for information about these counters. See also The `DBSPJ' Block (http://dev.mysql.com/doc/ndbapi/en/ndb-internals-kernel-blocks-dbspj.html), in the `MySQL Cluster API Developer Guide'. * `ndb_log_apply_status' Options for ndb-log-apply-status *Version Introduced* 5.1.51-ndb-7.0.21, 5.1.51-ndb-7.1.10 *Command-Line `--ndb-log-apply-status' Format* *Option-File Format* `ndb-log-apply-status' *Option Sets Yes, Variable* `ndb_log_apply_status' *Variable Name* `ndb_log_apply_status' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `boolean' *Default* `ON' A read-only variable which shows whether the server was started with the `--ndb-log-apply-status' option. This variable was added in MySQL Cluster NDB 7.0.21 and MySQL Cluster NDB 7.1.10. * `ndb_log_bin' Options for ndb_log_bin *Version Introduced* 5.1.6 *Command-Line `--ndb-log-bin={1|0}' Format* *Option Sets Yes, Variable* `ndb_log_bin' *Variable Name* `ndb_log_bin' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `boolean' *Default* `ON' Causes updates to `NDB' tables to be written to the binary log. Setting this variable has no effect if binary logging is not already enabled for the server using `log_bin'. `ndb_log_bin' defaults to 1 (ON); normally, there is never any need to change this value in a production environment. This variable was added in MySQL 5.1.6. * `ndb_log_binlog_index' Options for ndb_log_binlog_index *Version Introduced* 5.1.6 *Command-Line `--ndb-log-binlog-index={1|0}' Format* *Option Sets Yes, Variable* `ndb_log_binlog_index' *Variable Name* `ndb_log_binlog_index' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `boolean' *Default* `ON' Causes a mapping of epochs to positions in the binary log to be inserted into the `ndb_binlog_index' table. Setting this variable has no effect if binary logging is not already enabled for the server using `log_bin'. (In addition, `ndb_log_bin' must not be disabled.) `ndb_log_binlog_index' defaults to `1' (`ON'); normally, there is never any need to change this value in a production environment. This variable was added in MySQL 5.1.6. * `ndb_optimized_node_selection' Options for ndb_optimized_node_selection *Command-Line `--ndb-optimized-node-selection'4.1.9-5.1.22-ndb-6.33 Format* ** `--ndb-optimized-node-selection=#' *Option-File Format* `ndb_optimized_node_selection' *Permitted Values (<= 5.1.22-ndb-6.33)* *Type* `boolean' *Default* `ON' Prior to MySQL Cluster NDB 6.3.4 Causes an SQL node to use the `closest' data node as transaction coordinator. Enabled by default. Set to `0' or `OFF' to disable, in which case the SQL node uses each data node in the cluster in succession. When this option is disabled each SQL thread attempts to use a given data node 8 times before proceeding to the next one. Beginning with MySQL Cluster NDB 6.3.4 There are two forms of optimized node selection, described here: 1. The SQL node uses _promixity_ to determine the transaction coordinator; that is, the `closest' data node to the SQL node is chosen as the transaction coordinator. For this purpose, a data node having a shared memory connection with the SQL node is considered to be `closest' to the SQL node; the next closest (in order of decreasing proximity) are: TCP connection to `localhost'; SCI connection; TCP connection from a host other than `localhost'. 2. The SQL thread uses _distribution awareness_ to select the data node. That is, the data node housing the cluster partition accessed by the first statement of a given transaction is used as the transaction coordinator for the entire transaction. (This is effective only if the first statement of the transaction accesses no more than one cluster partition.) This option takes one of the integer values `0', `1', `2', or `3'. `3' is the default. These values affect node selection as follows: * `0': Node selection is not optimized. Each data node is employed as the transaction coordinator 8 times before the SQL thread proceeds to the next data node. (This is the same `round-robin' behavior as caused by setting this option to `0' or `OFF' in previous versions of MySQL Cluster.) * `1': Proximity to the SQL node is used to determine the transaction coordinator. (This is the same behavior as caused by setting this option to `1' or `ON' in previous MySQL versions.) * `2': Distribution awareness is used to select the transaction coordinator. However, if the first statement of the transaction accesses more than one cluster partition, the SQL node reverts to the round-robin behavior seen when this option is set to `0'. * `3': If distribution awareness can be employed to determine the transaction coordinator, then it is used; otherwise proximity is used to select the transaction coordinator. (This is the default behavior in MySQL Cluster NDB 6.3.4 and later.) *Important*: Beginning with MySQL Cluster NDB 6.3.4, it is no longer possible to set `--ndb_optimized_node_selection' to `ON' or `OFF'; attempting to do so causes *Note `mysqld': mysqld. to abort with an error. * `ndb_report_thresh_binlog_epoch_slip' Options for ndb_report_thresh_binlog_epoch_slip *Command-Line `--ndb_report_thresh_binlog_epoch_slip' Format* *Option-File Format* `ndb_report_thresh_binlog_epoch_slip' *Permitted Values * *Type* `numeric' *Default* `3' *Range* `0-256' This is a threshold on the number of epochs to be behind before reporting binlog status. For example, a value of `3' (the default) means that if the difference between which epoch has been received from the storage nodes and which epoch has been applied to the binlog is 3 or more, a status message will be sent to the cluster log. * `ndb_report_thresh_binlog_mem_usage' Options for ndb_report_thresh_binlog_mem_usage *Command-Line `--ndb_report_thresh_binlog_mem_usage' Format* *Option-File Format* `ndb_report_thresh_binlog_mem_usage' *Permitted Values * *Type* `numeric' *Default* `10' *Range* `0-10' This is a threshold on the percentage of free memory remaining before reporting binlog status. For example, a value of `10' (the default) means that if the amount of available memory for receiving binlog data from the data nodes falls below 10%, a status message will be sent to the cluster log. * `slave_allow_batching' Options for slave_allow_batching *Version Introduced* 5.1.19-ndb-6.2.3 *Command-Line `--slave-allow-batching' Format* *Option-File Format* `slave_allow_batching' *Option Sets Yes, Variable* `slave_allow_batching' *Variable Name* `slave_allow_batching' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `boolean' *Default* `off' Whether or not batched updates are enabled on MySQL Cluster replication slaves. This variable is available beginning with MySQL Cluster NDB 6.2.3. Currently, it is available for *Note `mysqld': mysqld. only as supplied with MySQL Cluster or built from the MySQL Cluster sources. For more information, see *Note mysql-cluster-replication-starting::. * `ndb_table_no_logging' Options for ndb_table_no_logging *Version Introduced* 5.1.23-ndb-6.3.8 *Variable Name* `ndb_table_no_logging' *Variable Scope* Session *Dynamic Variable* Yes *Permitted Values * *Type* `boolean' *Default* `FALSE' When this variable is set to `ON' or `1', it causes *Note `NDB': mysql-cluster. tables not to be checkpointed to disk. More specifically, this setting applies to tables which are created or altered using `ENGINE NDB' when `ndb_table_no_logging' is enabled, and continues to apply for the lifetime of the table, even if `ndb_table_no_logging' is later changed. Suppose that `A', `B', `C', and `D' are tables that we create (and perhaps also alter), and that we also change the setting for `ndb_table_no_logging' as shown here: SET @@ndb_table_no_logging = 1; CREATE TABLE A ... ENGINE NDB; CREATE TABLE B ... ENGINE MYISAM; CREATE TABLE C ... ENGINE MYISAM; ALTER TABLE B ENGINE NDB; SET @@ndb_table_no_logging = 0; CREATE TABLE D ... ENGINE NDB; ALTER TABLE C ENGINE NDB; SET @@ndb_table_no_logging = 1; After the previous sequence of events, tables `A' and `B' are not checkpointed; `A' was created with `ENGINE NDB' and B was altered to use `NDB', both while `ndb_table_no_logging' was enabled. However, tables `C' and `D' are logged; `C' was altered to use *Note `NDB': mysql-cluster. and `D' was created using `ENGINE NDB', both while `ndb_table_no_logging' was disabled. Setting `ndb_table_no_logging' back to `1' or `ON' does _not_ cause table `C' or `D' to be checkpointed. *Note*: `ndb_table_no_logging' has no effect on the creation of *Note `NDB': mysql-cluster. table schema files; to suppress these, use `ndb_table_temporary' instead. * `ndb_table_temporary' Options for ndb_table_temporary *Version Introduced* 5.1.23-ndb-6.3.8 *Variable Name* `ndb_table_temporary' *Variable Scope* Session *Dynamic Variable* Yes *Permitted Values * *Type* `boolean' *Default* `FALSE' When set to `ON' or `1', this variable causes *Note `NDB': mysql-cluster. tables not to be written to disk: This means that no table schema files are created, and that the tables are not logged. *Note*: Setting this variable currently has no effect in MySQL Cluster NDB 7.0 and later. This is a known issue; see BUG#34036. * `ndb_use_copying_alter_table' Options for ndb_use_copying_alter_table *Version Introduced* 5.1.12 *Variable Name* `ndb_use_copying_alter_table' *Variable Scope* Global, Session *Dynamic Variable* No Forces *Note `NDB': mysql-cluster. to use copying of tables in the event of problems with online *Note `ALTER TABLE': alter-table. operations. The default value is `OFF'. This variable was added in MySQL 5.1.12. * `ndb_use_exact_count' Options for ndb_use_exact_count *Variable Name* `ndb_use_exact_count' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `boolean' *Default* `ON' Forces *Note `NDB': mysql-cluster. to use a count of records during `SELECT COUNT(*)' query planning to speed up this type of query. The default value is `ON'. For faster queries overall, disable this feature by setting the value of `ndb_use_exact_count' to `OFF'. * `ndb_use_transactions' Options for ndb_use_transactions *Command-Line `--ndb_use_transactions' Format* *Option-File Format* `ndb_use_transactions' *Variable Name* `ndb_use_transactions' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `boolean' *Default* `ON' You can disable *Note `NDB': mysql-cluster. transaction support by setting this variable's values to `OFF' (not recommended). The default is `ON'. *Note*: The setting for this variable was not honored in MySQL Cluster NDB 6.4.3 and MySQL Cluster NDB 7.0.4. (Bug#43236) The system variables in the following list all relate to the *Note `ndbinfo': mysql-cluster-ndbinfo. information database. They were added in MySQL Cluster NDB 7.1.1. * `ndbinfo_database' Options for ndbinfo_database *Version Introduced* 5.1.41-ndb-7.1.1 *Variable Name* `ndbinfo_database' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `string' *Default* `ndbinfo' Shows the name used for the `NDB' information database; the default is `ndbinfo'. This is a read-only variable whose value is determined at compile time; you can set it by starting the server using `--ndbinfo-database=NAME', which sets the value shown for this variable but does not actually change the name used for the NDB information database. * `ndbinfo_max_bytes' Options for ndbinfo_max_bytes *Version Introduced* 5.1.41-ndb-7.1.1 *Command-Line `--ndbinfo-max-bytes=#' Format* *Option Sets Yes, Variable* `ndbinfo_max_bytes' *Variable Name* `ndbinfo_max_bytes' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `numeric' *Default* `0' Used in testing and debugging only. * `ndbinfo_max_rows' Options for ndbinfo_max_rows *Version Introduced* 5.1.41-ndb-7.1.1 *Command-Line `--ndbinfo-max-rows=#' Format* *Option Sets Yes, Variable* `ndbinfo_max_rows' *Variable Name* `ndbinfo_max_rows' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `numeric' *Default* `10' Used in testing and debugging only. * `ndbinfo_show_hidden' Options for ndbinfo_show_hidden *Version Introduced* 5.1.41-ndb-7.1.1 *Command-Line `--ndbinfo-show-hidden={0|1}' Format* *Option Sets Yes, Variable* `ndbinfo_show_hidden' *Variable Name* `ndbinfo_show_hidden' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `boolean' *Default* `no' Whether or not the *Note `ndbinfo': mysql-cluster-ndbinfo. database's underlying internal tables are shown in the `mysql' client. The default is `OFF'. * `ndbinfo_table_prefix' Options for ndbinfo_table_prefix *Version Introduced* 5.1.41-ndb-7.1.1 *Command-Line `--ndbinfo-table-prefix=name' Format* *Option Sets Yes, Variable* `ndbinfo_table_prefix' *Variable Name* `ndbinfo_table_prefix' *Variable Scope* Global, Session *Dynamic Variable* Yes *Permitted Values * *Type* `string' *Default* `ndb$' The prefix used in naming the ndbinfo database's base tables (normally hidden, unless exposed by setting `ndbinfo_show_hidden'). This is a read-only variable whose default value is ``ndb$''. You can start the server with the `--ndbinfo-table-prefix' option, but this merely sets the variable and does not change the actual prefix used to name the hidden base tables; the prefix itself is determined at compile time. * `ndbinfo_version' Options for ndbinfo_version *Version Introduced* 5.1.41-ndb-7.1.1 *Variable Name* `ndbinfo_version' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `string' *Default* `' Shows the version of the *Note `ndbinfo': mysql-cluster-ndbinfo. engine in use; read-only. * `server_id_bits' Options for server-id-bits *Version Introduced* 5.1.47-ndb-7.0.17, 5.1.47-ndb-7.1.6 *Command-Line `--server-id-bits=#' Format* *Option-File Format* `server-id-bits' *Option Sets Yes, Variable* `server_id_bits' *Variable Name* `server_id_bits' *Variable Scope* Global *Dynamic Variable* No *Permitted Values * *Type* `numeric' *Default* `32' *Range* `7-32' The effective value of `server_id' if the server was started with the `--server-id-bits' option set to a nondefault value. If the value of `server_id' greater than or equal to 2 to the power of `server_id_bits', *Note `mysqld': mysqld. refuses to start. This system variable was added in MySQL Cluster NDB 7.0.17 and MySQL Cluster NDB 7.1.6; it is supported only in these and later releases of MySQL Cluster. `server_id_bits' is not supported by the standard MySQL Server.  File: manual.info, Node: mysql-cluster-status-variables, Prev: mysql-cluster-system-variables, Up: mysql-cluster-options-variables 17.3.4.4 MySQL Cluster Status Variables ....................................... This section provides detailed information about MySQL server status variables that relate to MySQL Cluster and the *Note `NDB': mysql-cluster. storage engine. For status variables not specific to MySQL Cluster, and for general information on using status variables, see *Note server-status-variables::. * `Handler_discover' The MySQL server can ask the *Note `NDBCLUSTER': mysql-cluster. storage engine if it knows about a table with a given name. This is called discovery. `Handler_discover' indicates the number of times that tables have been discovered using this mechanism. * `Ndb_cluster_node_id' If the server is acting as a MySQL Cluster node, then the value of this variable its node ID in the cluster. If the server is not part of a MySQL Cluster, then the value of this variable is 0. * `Ndb_config_from_host' If the server is part of a MySQL Cluster, the value of this variable is the host name or IP address of the Cluster management server from which it gets its configuration data. If the server is not part of a MySQL Cluster, then the value of this variable is an empty string. Prior to MySQL 5.1.12, this variable was named `Ndb_connected_host'. * `Ndb_config_from_port' If the server is part of a MySQL Cluster, the value of this variable is the number of the port through which it is connected to the Cluster management server from which it gets its configuration data. If the server is not part of a MySQL Cluster, then the value of this variable is 0. Prior to MySQL 5.1.12, this variable was named `Ndb_connected_port'. * `Ndb_conflict_fn_max' Used in MySQL Cluster Replication conflict resolution, this variable shows the number of times that a row was not applied on the current SQL node due to `greatest timestamp wins' conflict resolution since the last time that this *Note `mysqld': mysqld. was started. This variable was added in MySQL Cluster NDB 6.3.3. For more information, see *Note mysql-cluster-replication-conflict-resolution::. * `Ndb_conflict_fn_old' Used in MySQL Cluster Replication conflict resolution, this variable shows the number of times that a row was not applied as the result of `same timestamp wins' conflict resolution on a given *Note `mysqld': mysqld. since the last time it was restarted. This variable was added in MySQL Cluster NDB 6.3.4. For more information, see *Note mysql-cluster-replication-conflict-resolution::. * `Ndb_execute_count' Provides the number of round trips to the *Note `NDB': mysql-cluster. kernel made by operations. Added in MySQL Cluster NDB 6.3.6. * `Ndb_number_of_data_nodes' If the server is part of a MySQL Cluster, the value of this variable is the number of data nodes in the cluster. If the server is not part of a MySQL Cluster, then the value of this variable is 0. Prior to MySQL 5.1.12, this variable was named `Ndb_number_of_storage_nodes'. * `Ndb_pushed_queries_defined' The total number of joins pushed down to the NDB kernel for distributed handling on the data nodes. Note that joins tested using *Note `EXPLAIN': explain. that can be pushed down contribute to this number. Added in MySQL Cluster NDB 7.2.0. * `Ndb_pushed_queries_dropped' The number of joins that were pushed down to the NDB kernel but that could not be handled there. Added in MySQL Cluster NDB 7.2.0. * `Ndb_pushed_queries_executed' The number of joins successfully pushed down to *Note `NDB': mysql-cluster. and executed there. Added in MySQL Cluster NDB 7.2.0. * `Ndb_pushed_reads' The number of rows returned to *Note `mysqld': mysqld. from the NDB kernel by joins that were pushed down. Note that executing *Note `EXPLAIN': explain. on joins that can be pushed down to *Note `NDB': mysql-cluster. does not add to this number. Added in MySQL Cluster NDB 7.2.0. * `Slave_heartbeat_period' Shows the replication heartbeat interval (in seconds) on a replication slave. This variable was added in MySQL Cluster NDB 6.3.4. * `Slave_received_heartbeats' This counter increments with each replication heartbeat received by a replication slave since the last time that the slave was restarted or reset, or a *Note `CHANGE MASTER TO': change-master-to. statement was issued. This variable was added in MySQL Cluster NDB 6.3.4. * `Ndb_pruned_scan_count' This variable holds a count of the number of scans executed by *Note `NDBCLUSTER': mysql-cluster. since the MySQL Cluster was last started where *Note `NDBCLUSTER': mysql-cluster. was able to use partition pruning. Using this variable together with `Ndb_scan_count' can be helpful in schema design to maximize the ability of the server to prune scans to a single table partition, thereby involving only a single data node. This variable was added in MySQL Cluster NDB 6.3.25 and MySQL Cluster NDB 7.0.5. * `Ndb_scan_count' This variable holds a count of the total number of scans executed by *Note `NDBCLUSTER': mysql-cluster. since the MySQL Cluster was last started. This variable was added in MySQL Cluster NDB 6.3.25 and MySQL Cluster NDB 7.0.5.  File: manual.info, Node: mysql-cluster-interconnects, Prev: mysql-cluster-options-variables, Up: mysql-cluster-configuration 17.3.5 Using High-Speed Interconnects with MySQL Cluster -------------------------------------------------------- * Menu: * mysql-cluster-sci-sockets:: Configuring MySQL Cluster to use SCI Sockets * mysql-cluster-interconnects-performance:: MySQL Cluster Interconnects and Performance Even before design of *Note `NDBCLUSTER': mysql-cluster. began in 1996, it was evident that one of the major problems to be encountered in building parallel databases would be communication between the nodes in the network. For this reason, *Note `NDBCLUSTER': mysql-cluster. was designed from the very beginning to permit the use of a number of different data transport mechanisms. In this Manual, we use the term _transporter_ for these. The MySQL Cluster codebase provides for four different transporters: * _TCP/IP using 100 Mbps or gigabit Ethernet_, as discussed in *Note mysql-cluster-tcp-definition::. * _Direct (machine-to-machine) TCP/IP_; although this transporter uses the same TCP/IP protocol as mentioned in the previous item, it requires setting up the hardware differently and is configured differently as well. For this reason, it is considered a separate transport mechanism for MySQL Cluster. See *Note mysql-cluster-tcp-definition-direct::, for details. * _Shared memory (SHM)_. For more information about SHM, see *Note mysql-cluster-shm-definition::. *Note*: SHM is considered experimental only, and is not officially supported. * _Scalable Coherent Interface (SCI)_, as described in the next section of this chapter, *Note mysql-cluster-sci-definition::. Most users today employ TCP/IP over Ethernet because it is ubiquitous. TCP/IP is also by far the best-tested transporter for use with MySQL Cluster. We are working to make sure that communication with the *Note `ndbd': mysql-cluster-programs-ndbd. process is made in `chunks' that are as large as possible because this benefits all types of data transmission. For users who desire it, it is also possible to use cluster interconnects to enhance performance even further. There are two ways to achieve this: Either a custom transporter can be designed to handle this case, or you can use socket implementations that bypass the TCP/IP stack to one extent or another. We have experimented with both of these techniques using the SCI (Scalable Coherent Interface) technology developed by Dolphin Interconnect Solutions (http://www.dolphinics.com/).  File: manual.info, Node: mysql-cluster-sci-sockets, Next: mysql-cluster-interconnects-performance, Prev: mysql-cluster-interconnects, Up: mysql-cluster-interconnects 17.3.5.1 Configuring MySQL Cluster to use SCI Sockets ..................................................... It is possible employing Scalable Coherent Interface (SCI) technology to achieve a significant increase in connection speeds and throughput between MySQL Cluster data and SQL nodes. To use SCI, it is necessary to obtain and install Dolphin SCI network cards and to use the drivers and other software supplied by Dolphin. You can get information on obtaining these, from Dolphin Interconnect Solutions (http://www.dolphinics.com/). SCI SuperSocket or SCI Transporter support is available for 32-bit and 64-bit Linux, Solaris, Windows, and other platforms. See the Dolphin documentation referenced later in this section for more detailed information regarding platforms supported for SCI. *Note*: Prior to MySQL 5.1.20, there were issues with building MySQL Cluster with SCI support (see Bug#25470), but these have been resolved due to work contributed by Dolphin. SCI Sockets are now correctly supported for MySQL Cluster hosts running recent versions of Linux using the `-max' builds, and versions of MySQL Cluster with SCI Transporter support can be built using either of `compile-amd64-max-sci' or `compile-pentium64-max-sci'. Both of these build scripts can be found in the `BUILD' directory of the MySQL Cluster source trees; it should not be difficult to adapt them for other platforms. Generally, all that is necessary is to compile MySQL Cluster with SCI Transporter support is to configure the MySQL Cluster build using `--with-ndb-sci=/opt/DIS'. Once you have acquired the required Dolphin hardware and software, you can obtain detailed information on how to adapt a MySQL Cluster configured for normal TCP/IP communication to use SCI from the `Dolphin Express for MySQL Installation and Reference Guide', available for download at `http://docsrva.mysql.com/public/DIS_install_guide_book.pdf' (PDF file, 94 pages, 753 KB). This document provides instructions for installing the SCI hardware and software, as well as information concerning network topology and configuration.  File: manual.info, Node: mysql-cluster-interconnects-performance, Prev: mysql-cluster-sci-sockets, Up: mysql-cluster-interconnects 17.3.5.2 MySQL Cluster Interconnects and Performance .................................................... The *Note `ndbd': mysql-cluster-programs-ndbd. process has a number of simple constructs which are used to access the data in a MySQL Cluster. We have created a very simple benchmark to check the performance of each of these and the effects which various interconnects have on their performance. There are four access methods: * Primary key access This is access of a record through its primary key. In the simplest case, only one record is accessed at a time, which means that the full cost of setting up a number of TCP/IP messages and a number of costs for context switching are borne by this single request. In the case where multiple primary key accesses are sent in one batch, those accesses share the cost of setting up the necessary TCP/IP messages and context switches. If the TCP/IP messages are for different destinations, additional TCP/IP messages need to be set up. * Unique key access Unique key accesses are similar to primary key accesses, except that a unique key access is executed as a read on an index table followed by a primary key access on the table. However, only one request is sent from the MySQL Server, and the read of the index table is handled by *Note `ndbd': mysql-cluster-programs-ndbd. Such requests also benefit from batching. * Full table scan When no indexes exist for a lookup on a table, a full table scan is performed. This is sent as a single request to the *Note `ndbd': mysql-cluster-programs-ndbd. process, which then divides the table scan into a set of parallel scans on all cluster *Note `ndbd': mysql-cluster-programs-ndbd. processes. In future versions of MySQL Cluster, an SQL node will be able to filter some of these scans. * Range scan using ordered index When an ordered index is used, it performs a scan in the same manner as the full table scan, except that it scans only those records which are in the range used by the query transmitted by the MySQL server (SQL node). All partitions are scanned in parallel when all bound index attributes include all attributes in the partitioning key. With benchmarks developed internally by MySQL for testing simple and batched primary and unique key accesses, we have found that using SCI sockets improves performance by approximately 100% over TCP/IP, except in rare instances when communication performance is not an issue. This can occur when scan filters make up most of processing time or when very large batches of primary key accesses are achieved. In that case, the CPU processing in the *Note `ndbd': mysql-cluster-programs-ndbd. processes becomes a fairly large part of the overhead. Using the SCI transporter instead of SCI Sockets is only of interest in communicating between *Note `ndbd': mysql-cluster-programs-ndbd. processes. Using the SCI transporter is also only of interest if a CPU can be dedicated to the *Note `ndbd': mysql-cluster-programs-ndbd. process because the SCI transporter ensures that this process will never go to sleep. It is also important to ensure that the *Note `ndbd': mysql-cluster-programs-ndbd. process priority is set in such a way that the process does not lose priority due to running for an extended period of time, as can be done by locking processes to CPUs in Linux 2.6. If such a configuration is possible, the *Note `ndbd': mysql-cluster-programs-ndbd. process will benefit by 10-70% as compared with using SCI sockets. (The larger figures will be seen when performing updates and probably on parallel scan operations as well.) There are several other optimized socket implementations for computer clusters, including Myrinet, Gigabit Ethernet, Infiniband and the VIA interface. However, we have tested MySQL Cluster so far only with SCI sockets. See *Note mysql-cluster-sci-sockets::, for information on how to set up SCI sockets using ordinary TCP/IP for MySQL Cluster.  File: manual.info, Node: mysql-cluster-programs, Next: mysql-cluster-management, Prev: mysql-cluster-configuration, Up: mysql-cluster 17.4 MySQL Cluster Programs =========================== * Menu: * mysql-cluster-programs-mysqld:: MySQL Server Usage for MySQL Cluster * mysql-cluster-programs-ndbd:: `ndbd' --- The MySQL Cluster Data Node Daemon * mysql-cluster-programs-ndbmtd:: `ndbmtd' --- The MySQL Cluster Data Node Daemon (Multi-Threaded) * mysql-cluster-programs-ndb-mgmd:: `ndb_mgmd' --- The MySQL Cluster Management Server Daemon * mysql-cluster-programs-ndb-mgm:: `ndb_mgm' --- The MySQL Cluster Management Client * mysql-cluster-programs-ndb-config:: `ndb_config' --- Extract MySQL Cluster Configuration Information * mysql-cluster-programs-ndb-cpcd:: `ndb_cpcd' --- Automate Testing for NDB Development * mysql-cluster-programs-ndb-delete-all:: `ndb_delete_all' --- Delete All Rows from an NDB Table * mysql-cluster-programs-ndb-desc:: `ndb_desc' --- Describe NDB Tables * mysql-cluster-programs-ndb-drop-index:: `ndb_drop_index' --- Drop Index from an NDB Table * mysql-cluster-programs-ndb-drop-table:: `ndb_drop_table' --- Drop an NDB Table * mysql-cluster-programs-ndb-error-reporter:: `ndb_error_reporter' --- NDB Error-Reporting Utility * mysql-cluster-programs-ndb-print-backup-file:: `ndb_print_backup_file' --- Print NDB Backup File Contents * mysql-cluster-programs-ndb-print-schema-file:: `ndb_print_schema_file' --- Print NDB Schema File Contents * mysql-cluster-programs-ndb-print-sys-file:: `ndb_print_sys_file' --- Print NDB System File Contents * mysql-cluster-programs-ndbd-redo-log-reader:: `ndbd_redo_log_reader' --- Check and Print Content of Cluster Redo Log * mysql-cluster-programs-ndb-restore:: `ndb_restore' --- Restore a MySQL Cluster Backup * mysql-cluster-programs-ndb-select-all:: `ndb_select_all' --- Print Rows from an NDB Table * mysql-cluster-programs-ndb-select-count:: `ndb_select_count' --- Print Row Counts for NDB Tables * mysql-cluster-programs-ndb-show-tables:: `ndb_show_tables' --- Display List of NDB Tables * mysql-cluster-programs-ndb-size-pl:: `ndb_size.pl' --- NDBCLUSTER Size Requirement Estimator * mysql-cluster-programs-ndb-waiter:: `ndb_waiter' --- Wait for MySQL Cluster to Reach a Given Status * mysql-cluster-program-options-common:: Options Common to MySQL Cluster Programs Using and managing a MySQL Cluster requires several specialized programs, which we describe in this chapter. We discuss the purposes of these programs in a MySQL Cluster, how to use the programs, and what startup options are available for each of them. These programs include the MySQL Cluster data, management, and SQL node processes (*Note `ndbd': mysql-cluster-programs-ndbd, *Note `ndbmtd': mysql-cluster-programs-ndbmtd, *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd, and *Note `mysqld': mysqld.) and the management client (*Note `ndb_mgm': mysql-cluster-programs-ndb-mgm.). Other *Note `NDB': mysql-cluster. utility, diagnostic, and example programs are included with the MySQL Cluster distribution. These include *Note `ndb_restore': mysql-cluster-programs-ndb-restore, *Note `ndb_show_tables': mysql-cluster-programs-ndb-show-tables, and *Note `ndb_config': mysql-cluster-programs-ndb-config. These programs are covered later in this chapter. The last two sections of this chapter contain tables of options used, respectively, with *Note `mysqld': mysqld. and with the various MySQL Cluster programs.  File: manual.info, Node: mysql-cluster-programs-mysqld, Next: mysql-cluster-programs-ndbd, Prev: mysql-cluster-programs, Up: mysql-cluster-programs 17.4.1 MySQL Server Usage for MySQL Cluster ------------------------------------------- *Note `mysqld': mysqld. is the traditional MySQL server process. To be used with MySQL Cluster, *Note `mysqld': mysqld. needs to be built with support for the *Note `NDBCLUSTER': mysql-cluster. storage engine, as it is in the precompiled binaries available from `http://dev.mysql.com/downloads/'. If you build MySQL from source, you must invoke `configure' with one of the options to enable *Note `NDBCLUSTER': mysql-cluster. storage engine support: * `--with-plugins=ndbcluster' * `--with-plugins=max' * `--with-plugins=max-no-innodb' (`--with-ndbcluster' also works to enable *Note `NDBCLUSTER': mysql-cluster. support, but is deprecated and so produces a `configure' warning as of MySQL 5.1.9.) For information about other MySQL server options and variables relevant to MySQL Cluster in addition to those discussed in this section, see *Note mysql-cluster-options-variables::. If the *Note `mysqld': mysqld. binary has been built with Cluster support, the *Note `NDBCLUSTER': mysql-cluster. storage engine is still disabled by default. You can use either of two possible options to enable this engine: * Use `--ndbcluster' as a startup option on the command line when starting *Note `mysqld': mysqld. * Insert a line containing `ndbcluster' in the `[mysqld]' section of your `my.cnf' file. An easy way to verify that your server is running with the *Note `NDBCLUSTER': mysql-cluster. storage engine enabled is to issue the *Note `SHOW ENGINES': show-engines. statement in the MySQL Monitor (*Note `mysql': mysql.). You should see the value `YES' as the `Support' value in the row for *Note `NDBCLUSTER': mysql-cluster. If you see `NO' in this row or if there is no such row displayed in the output, you are not running an *Note `NDB': mysql-cluster.-enabled version of MySQL. If you see `DISABLED' in this row, you need to enable it in either one of the two ways just described. To read cluster configuration data, the MySQL server requires at a minimum three pieces of information: * The MySQL server's own cluster node ID * The host name or IP address for the management server (MGM node) * The number of the TCP/IP port on which it can connect to the management server Node IDs can be allocated dynamically, so it is not strictly necessary to specify them explicitly. The *Note `mysqld': mysqld. parameter `ndb-connectstring' is used to specify the connectstring either on the command line when starting *Note `mysqld': mysqld. or in `my.cnf'. The connectstring contains the host name or IP address where the management server can be found, as well as the TCP/IP port it uses. In the following example, `ndb_mgmd.mysql.com' is the host where the management server resides, and the management server listens for cluster messages on port 1186: shell> mysqld --ndbcluster --ndb-connectstring=ndb_mgmd.mysql.com:1186 See *Note mysql-cluster-connectstring::, for more information on connectstrings. Given this information, the MySQL server will be a full participant in the cluster. (We often refer to a *Note `mysqld': mysqld. process running in this manner as an SQL node.) It will be fully aware of all cluster data nodes as well as their status, and will establish connections to all data nodes. In this case, it is able to use any data node as a transaction coordinator and to read and update node data. You can see in the *Note `mysql': mysql. client whether a MySQL server is connected to the cluster using *Note `SHOW PROCESSLIST': show-processlist. If the MySQL server is connected to the cluster, and you have the `PROCESS' privilege, then the first row of the output is as shown here: mysql> SHOW PROCESSLIST \G *************************** 1. row *************************** Id: 1 User: system user Host: db: Command: Daemon Time: 1 State: Waiting for event from ndbcluster Info: NULL *Important*: To participate in a MySQL Cluster, the *Note `mysqld': mysqld. process must be started with _both_ the options `--ndbcluster' and `--ndb-connectstring' (or their equivalents in `my.cnf'). If *Note `mysqld': mysqld. is started with only the `--ndbcluster' option, or if it is unable to contact the cluster, it is not possible to work with *Note `NDB': mysql-cluster. tables, _nor is it possible to create any new tables regardless of storage engine_. The latter restriction is a safety measure intended to prevent the creation of tables having the same names as *Note `NDB': mysql-cluster. tables while the SQL node is not connected to the cluster. If you wish to create tables using a different storage engine while the *Note `mysqld': mysqld. process is not participating in a MySQL Cluster, you must restart the server _without_ the `--ndbcluster' option.  File: manual.info, Node: mysql-cluster-programs-ndbd, Next: mysql-cluster-programs-ndbmtd, Prev: mysql-cluster-programs-mysqld, Up: mysql-cluster-programs 17.4.2 `ndbd' -- The MySQL Cluster Data Node Daemon --------------------------------------------------- *Note `ndbd': mysql-cluster-programs-ndbd. is the process that is used to handle all the data in tables using the NDB Cluster storage engine. This is the process that empowers a data node to accomplish distributed transaction handling, node recovery, checkpointing to disk, online backup, and related tasks. In a MySQL Cluster, a set of *Note `ndbd': mysql-cluster-programs-ndbd. processes cooperate in handling data. These processes can execute on the same computer (host) or on different computers. The correspondences between data nodes and Cluster hosts is completely configurable. The following table includes command options specific to the MySQL Cluster data node program *Note `ndbd': mysql-cluster-programs-ndbd. Additional descriptions follow the table. For options common to all MySQL Cluster programs, see *Note mysql-cluster-program-options-common::. *`ndbd' Command Line Options* Format Description IntroductionDeprecatedRemoved -bind-address=nameLocal bind address 5.1.12 -daemon Start ndbd as daemon (default); override with -nodaemon -foreground Run ndbd in foreground, provided for debugging purposes (implies -nodaemon) -initial Perform initial start of ndbd, including cleaning the file system. Consult the documentation before using this option -initial-start Perform partial initial start 5.1.11 (requires -nowait-nodes) -install[=name]Used to install the data node 5.1.47-ndb-7.0.16, process as a Windows service. Does 5.1.47-ndb-7.1.5 not apply on non-Windows platforms. -nodaemon Do not start ndbd as daemon; provided for testing purposes -nostart Don't start ndbd immediately; ndbd waits for command to start from ndb_mgmd -nowait-nodes=listDo not wait for these data nodes to 5.1.9 start (takes comma-separated list of node IDs). Also requires -ndb-nodeid to be used. -remove[=name] Used to remove a data node process 5.1.47-ndb-7.0.16, that was previously installed as a 5.1.47-ndb-7.1.5 Windows service. Does not apply on non-Windows platforms. *Note*: All of these options also apply to the multi-threaded version of this program (*Note `ndbmtd': mysql-cluster-programs-ndbmtd, available in MySQL Cluster NDB 7.0 and later) and you may substitute `*Note `ndbmtd': mysql-cluster-programs-ndbmtd.' for `*Note `ndbd': mysql-cluster-programs-ndbd.' wherever the latter occurs in this section. For options common to all *Note `NDBCLUSTER': mysql-cluster. programs, see *Note mysql-cluster-program-options-common::. * `--bind-address' Options for bind-address *Version Introduced* 5.1.12 *Command-Line `--bind-address=name' Format* *Permitted Values * *Type* `string' *Default* `' Causes *Note `ndbd': mysql-cluster-programs-ndbd. to bind to a specific network interface (host name or IP address). This option has no default value. This option was added in MySQL 5.1.12. * `--daemon', `-d' Options for daemon *Command-Line `--daemon' Format* ** `-d' *Permitted Values * *Type* `boolean' *Default* `TRUE' Instructs *Note `ndbd': mysql-cluster-programs-ndbd. to execute as a daemon process. This is the default behavior. `--nodaemon' can be used to prevent the process from running as a daemon. This option has no effect when running *Note `ndbd': mysql-cluster-programs-ndbd. or *Note `ndbmtd': mysql-cluster-programs-ndbmtd. on Windows platforms. * `--initial' Options for initial *Command-Line `--initial' Format* *Permitted Values * *Type* `boolean' *Default* `FALSE' Instructs *Note `ndbd': mysql-cluster-programs-ndbd. to perform an initial start. An initial start erases any files created for recovery purposes by earlier instances of *Note `ndbd': mysql-cluster-programs-ndbd. It also re-creates recovery log files. Note that on some operating systems this process can take a substantial amount of time. An `--initial' start is to be used _only_ when starting the *Note `ndbd': mysql-cluster-programs-ndbd. process under very special circumstances; this is because this option causes all files to be removed from the MySQL Cluster file system and all redo log files to be re-created. These circumstances are listed here: * When performing a software upgrade which has changed the contents of any files. * When restarting the node with a new version of *Note `ndbd': mysql-cluster-programs-ndbd. * As a measure of last resort when for some reason the node restart or system restart repeatedly fails. In this case, be aware that this node can no longer be used to restore data due to the destruction of the data files. Use of this option prevents the `StartPartialTimeout' and `StartPartitionedTimeout' configuration parameters from having any effect. *Important*: This option does _not_ affect either of the following types of files: * Backup files that have already been created by the affected node * MySQL Cluster Disk Data files (see *Note mysql-cluster-disk-data::). This option also has no effect on recovery of data by a data node that is just starting (or restarting) from data nodes that are already running. This recovery of data occurs automatically, and requires no user intervention in a MySQL Cluster that is running normally. It is permissible to use this option when starting the cluster for the very first time (that is, before any data node files have been created); however, it is _not_ necessary to do so. * `--initial-start' Options for initial-start *Version Introduced* 5.1.11 *Command-Line `--initial-start' Format* *Permitted Values * *Type* `boolean' *Default* `FALSE' This option is used when performing a partial initial start of the cluster. Each node should be started with this option, as well as `--nowait-nodes'. Suppose that you have a 4-node cluster whose data nodes have the IDs 2, 3, 4, and 5, and you wish to perform a partial initial start using only nodes 2, 4, and 5--that is, omitting node 3: shell> ndbd --ndb-nodeid=2 --nowait-nodes=3 --initial-start shell> ndbd --ndb-nodeid=4 --nowait-nodes=3 --initial-start shell> ndbd --ndb-nodeid=5 --nowait-nodes=3 --initial-start Prior to MySQL 5.1.19, it was not possible to perform DDL operations involving Disk Data tables on a partially started cluster. (See Bug#24631.) When using this option, you must also specify the node ID for the data node being started with the `--ndb-nodeid' option. This option was added in MySQL 5.1.11. *Important*: Do not confuse this option with the `--nowait-nodes' option added for *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. in MySQL Cluster NDB 7.0.10, which can be used to enable a cluster configured with multiple management servers to be started without all management servers being online. * `--nowait-nodes=NODE_ID_1[, NODE_ID_2[, ...]]' Options for nowait-nodes *Version Introduced* 5.1.9 *Command-Line `--nowait-nodes=list' Format* *Permitted Values * *Type* `string' *Default* `' This option takes a list of data nodes which for which the cluster will not wait for before starting. This can be used to start the cluster in a partitioned state. For example, to start the cluster with only half of the data nodes (nodes 2, 3, 4, and 5) running in a 4-node cluster, you can start each *Note `ndbd': mysql-cluster-programs-ndbd. process with `--nowait-nodes=3,5'. In this case, the cluster starts as soon as nodes 2 and 4 connect, and does _not_ wait `StartPartitionedTimeout' milliseconds for nodes 3 and 5 to connect as it would otherwise. If you wanted to start up the same cluster as in the previous example without one *Note `ndbd': mysql-cluster-programs-ndbd. (say, for example, that the host machine for node 3 has suffered a hardware failure) then start nodes 2, 4, and 5 with `--nowait-nodes=3'. Then the cluster will start as soon as nodes 2, 4, and 5 connect and will not wait for node 3 to start. This option was added in MySQL 5.1.9. * `--nodaemon' Options for nodaemon *Command-Line `--nodaemon' Format* *Permitted Values * *Type* `boolean' *Default* `FALSE' *Permitted Values * *Type* (windows) `boolean' *Default* `TRUE' Instructs *Note `ndbd': mysql-cluster-programs-ndbd. not to start as a daemon process. This is useful when *Note `ndbd': mysql-cluster-programs-ndbd. is being debugged and you want output to be redirected to the screen. As of MySQL Cluster NDB 7.0.8, the default behavior for *Note `ndbd': mysql-cluster-programs-ndbd. and *Note `ndbmtd': mysql-cluster-programs-ndbmtd. on Windows is to run in the foreground, making this option unnecessary on Windows platforms. (Bug#45588) * `--nostart', `-n' Options for nostart *Command-Line `--nostart' Format* ** `-n' *Permitted Values * *Type* `boolean' *Default* `FALSE' Instructs *Note `ndbd': mysql-cluster-programs-ndbd. not to start automatically. When this option is used, *Note `ndbd': mysql-cluster-programs-ndbd. connects to the management server, obtains configuration data from it, and initializes communication objects. However, it does not actually start the execution engine until specifically requested to do so by the management server. This can be accomplished by issuing the proper `START' command in the management client (see *Note mysql-cluster-mgm-client-commands::). * `--install[=NAME]' Options for install *Version Introduced* 5.1.47-ndb-7.0.16, 5.1.47-ndb-7.1.5 *Command-Line `--install[=name]' Format* *Permitted Values * *Type* (windows) `string' *Default* `ndbd' Causes *Note `ndbd': mysql-cluster-programs-ndbd. to be installed as a Windows service. Optionally, you can specify a name for the service; if not set, the service name defaults to `ndbd'. Although it is preferable to specify other *Note `ndbd': mysql-cluster-programs-ndbd. program options in a `my.ini' or `my.cnf' configuration file, it is possible to use together with `--install'. However, in such cases, the `--install' option must be specified first, before any other options are given, for the Windows service installation to succeed. It is generally not advisable to use this option together with the `--initial' option, since this causes the data node file system to be wiped and rebuilt every time the service is stopped and started. Extreme care should also be taken if you intend to use any of the other *Note `ndbd': mysql-cluster-programs-ndbd. options that affect the starting of data nodes--including `--initial-start', `--nostart', and `--nowait-nodes'--together with `--install', and you should make absolutely certain you fully understand and allow for any possible consequences of doing so. The `--install' option has no effect on non-Windows platforms. This option became available in MySQL Cluster NDB 7.0.16 and MySQL Cluster NDB 7.1.5. * `--remove[=NAME]' Options for remove *Version Introduced* 5.1.47-ndb-7.0.16, 5.1.47-ndb-7.1.5 *Command-Line `--remove[=name]' Format* *Permitted Values * *Type* (windows) `string' *Default* `ndbd' Causes an *Note `ndbd': mysql-cluster-programs-ndbd. process that was previously installed as a Windows service to be removed. Optionally, you can specify a name for the service to be uninstalled; if not set, the service name defaults to `ndbd'. The `--remove' option has no effect on non-Windows platforms. This option became available in MySQL Cluster NDB 7.0.16 and MySQL Cluster NDB 7.1.5. *Note `ndbd': mysql-cluster-programs-ndbd. generates a set of log files which are placed in the directory specified by `DataDir' in the `config.ini' configuration file. These log files are listed below. NODE_ID is the node's unique identifier. Note that NODE_ID represents the node's unique identifier. For example, `ndb_2_error.log' is the error log generated by the data node whose node ID is `2'. * `ndb_NODE_ID_error.log' is a file containing records of all crashes which the referenced *Note `ndbd': mysql-cluster-programs-ndbd. process has encountered. Each record in this file contains a brief error string and a reference to a trace file for this crash. A typical entry in this file might appear as shown here: Date/Time: Saturday 30 July 2004 - 00:20:01 Type of error: error Message: Internal program error (failed ndbrequire) Fault ID: 2341 Problem data: DbtupFixAlloc.cpp Object of reference: DBTUP (Line: 173) ProgramName: NDB Kernel ProcessID: 14909 TraceFile: ndb_2_trace.log.2 ***EOM*** Listings of possible *Note `ndbd': mysql-cluster-programs-ndbd. exit codes and messages generated when a data node process shuts down prematurely can be found in `ndbd' Error Messages (http://dev.mysql.com/doc/ndbapi/en/ndbd-error-messages.html). *Important*: _The last entry in the error log file is not necessarily the newest one_ (nor is it likely to be). Entries in the error log are _not_ listed in chronological order; rather, they correspond to the order of the trace files as determined in the `ndb_NODE_ID_trace.log.next' file (see below). Error log entries are thus overwritten in a cyclical and not sequential fashion. * `ndb_NODE_ID_trace.log.TRACE_ID' is a trace file describing exactly what happened just before the error occurred. This information is useful for analysis by the MySQL Cluster development team. It is possible to configure the number of these trace files that will be created before old files are overwritten. TRACE_ID is a number which is incremented for each successive trace file. * `ndb_NODE_ID_trace.log.next' is the file that keeps track of the next trace file number to be assigned. * `ndb_NODE_ID_out.log' is a file containing any data output by the *Note `ndbd': mysql-cluster-programs-ndbd. process. This file is created only if *Note `ndbd': mysql-cluster-programs-ndbd. is started as a daemon, which is the default behavior. * `ndb_NODE_ID.pid' is a file containing the process ID of the *Note `ndbd': mysql-cluster-programs-ndbd. process when started as a daemon. It also functions as a lock file to avoid the starting of nodes with the same identifier. * `ndb_NODE_ID_signal.log' is a file used only in debug versions of *Note `ndbd': mysql-cluster-programs-ndbd, where it is possible to trace all incoming, outgoing, and internal messages with their data in the *Note `ndbd': mysql-cluster-programs-ndbd. process. It is recommended not to use a directory mounted through NFS because in some environments this can cause problems whereby the lock on the `.pid' file remains in effect even after the process has terminated. To start *Note `ndbd': mysql-cluster-programs-ndbd, it may also be necessary to specify the host name of the management server and the port on which it is listening. Optionally, one may also specify the node ID that the process is to use. shell> ndbd --connect-string="nodeid=2;host=ndb_mgmd.mysql.com:1186" See *Note mysql-cluster-connectstring::, for additional information about this issue. *Note mysql-cluster-programs-ndbd::, describes other options for *Note `ndbd': mysql-cluster-programs-ndbd. When *Note `ndbd': mysql-cluster-programs-ndbd. starts, it actually initiates two processes. The first of these is called the `angel process'; its only job is to discover when the execution process has been completed, and then to restart the *Note `ndbd': mysql-cluster-programs-ndbd. process if it is configured to do so. Thus, if you attempt to kill *Note `ndbd': mysql-cluster-programs-ndbd. using the Unix *Note `kill': kill. command, it is necessary to kill both processes, beginning with the angel process. The preferred method of terminating an *Note `ndbd': mysql-cluster-programs-ndbd. process is to use the management client and stop the process from there. The execution process uses one thread for reading, writing, and scanning data, as well as all other activities. This thread is implemented asynchronously so that it can easily handle thousands of concurrent actions. In addition, a watch-dog thread supervises the execution thread to make sure that it does not hang in an endless loop. A pool of threads handles file I/O, with each thread able to handle one open file. Threads can also be used for transporter connections by the transporters in the *Note `ndbd': mysql-cluster-programs-ndbd. process. In a multi-processor system performing a large number of operations (including updates), the *Note `ndbd': mysql-cluster-programs-ndbd. process can consume up to 2 CPUs if permitted to do so. For a machine with many CPUs it is possible to use several *Note `ndbd': mysql-cluster-programs-ndbd. processes which belong to different node groups; however, such a configuration is still considered experimental and is not supported for MySQL 5.1 in a production setting. See *Note mysql-cluster-limitations::.  File: manual.info, Node: mysql-cluster-programs-ndbmtd, Next: mysql-cluster-programs-ndb-mgmd, Prev: mysql-cluster-programs-ndbd, Up: mysql-cluster-programs 17.4.3 `ndbmtd' -- The MySQL Cluster Data Node Daemon (Multi-Threaded) ---------------------------------------------------------------------- *Note `ndbmtd': mysql-cluster-programs-ndbmtd. is a multi-threaded version of *Note `ndbd': mysql-cluster-programs-ndbd, the process that is used to handle all the data in tables using the *Note `NDBCLUSTER': mysql-cluster. storage engine. *Note `ndbmtd': mysql-cluster-programs-ndbmtd. is intended for use on host computers having multiple CPU cores. Except where otherwise noted, *Note `ndbmtd': mysql-cluster-programs-ndbmtd. functions in the same way as *Note `ndbd': mysql-cluster-programs-ndbd.; therefore, in this section, we concentrate on the ways in which *Note `ndbmtd': mysql-cluster-programs-ndbmtd. differs from *Note `ndbd': mysql-cluster-programs-ndbd, and you should consult *Note mysql-cluster-programs-ndbd::, for additional information about running MySQL Cluster data nodes that apply to both the single-threaded and multi-threaded versions of the data node process. Command-line options and configuration parameters used with *Note `ndbd': mysql-cluster-programs-ndbd. also apply to *Note `ndbmtd': mysql-cluster-programs-ndbmtd. For more information about these options and parameters, see *Note mysql-cluster-programs-ndbd::, and *Note mysql-cluster-ndbd-definition::, respectively. *Note `ndbmtd': mysql-cluster-programs-ndbmtd. is also file system-compatible with *Note `ndbd': mysql-cluster-programs-ndbd. In other words, a data node running *Note `ndbd': mysql-cluster-programs-ndbd. can be stopped, the binary replaced with *Note `ndbmtd': mysql-cluster-programs-ndbmtd, and then restarted without any loss of data. (However, when doing this, you must make sure that `MaxNoOfExecutionThreads' is set to an apppriate value before restarting the node if you wish for *Note `ndbmtd': mysql-cluster-programs-ndbmtd. to run in multi-threaded fashion.) Similarly, an *Note `ndbmtd': mysql-cluster-programs-ndbmtd. binary can be replaced with *Note `ndbd': mysql-cluster-programs-ndbd. simply by stopping the node and then starting *Note `ndbd': mysql-cluster-programs-ndbd. in place of the multi-threaded binary. It is not necessary when switching between the two to start the data node binary using `--initial'. Prior to MySQL Cluster NDB 7.0.6, there were known issues when using *Note `ndbmtd': mysql-cluster-programs-ndbmtd. with MySQL Cluster Disk Data tables. If you wish to use multi-threaded data nodes with disk-based `NDB' tables, you should ensure that you are running MySQL Cluster NDB 7.0.6 or later (see Bug#41915 and Bug#44915) Using *Note `ndbmtd': mysql-cluster-programs-ndbmtd. differs from using *Note `ndbd': mysql-cluster-programs-ndbd. in two key respects: 1. You must set an appropriate value for the `MaxNoOfExecutionThreads' configuration parameter in the `config.ini' file. If you do not do so, *Note `ndbmtd': mysql-cluster-programs-ndbmtd. runs in single-threaded mode; that is, it behaves like *Note `ndbd': mysql-cluster-programs-ndbd. 2. Trace files are generated by critical errors in *Note `ndbmtd': mysql-cluster-programs-ndbmtd. processes in a somewhat different fashion from how these are generated by *Note `ndbd': mysql-cluster-programs-ndbd. failures. These differences are discussed in more detail in the next few paragraphs. Number of execution threads The `MaxNoOfExecutionThreads' configuration parameter is used to determine the number of local query handler (LQH) threads spawned by *Note `ndbmtd': mysql-cluster-programs-ndbmtd. Although this parameter is set in `[ndbd]' or `[ndbd default]' sections of the `config.ini' file, it is exclusive to *Note `ndbmtd': mysql-cluster-programs-ndbmtd. and does not apply to *Note `ndbd': mysql-cluster-programs-ndbd. This parameter takes an integer value from 2 to 8 inclusive. Generally, you should set this parameter equal to the number of CPU cores on the data node host, as shown in the following table: Number of Cores Recommended `MaxNoOfExecutionThreads' Value 2 2 4 4 8 or more 8 (It is possible to set this parameter to other values within the permitted range, but these are automatically rounded as shown in the *Value Used* column of the next table in this section.) The multi-threaded data node process always spawns at least 4 threads, listed here: * 1 local query handler (LQH) thread * 1 transaction coordinator (TC) thread * 1 transporter thread * 1 subscription manager (SUMA) thread Setting this parameter to a value between 4 and 8 inclusive causes additional LQH threads to be used by *Note `ndbmtd': mysql-cluster-programs-ndbmtd. (up to a maximum of 4 LQH threads), as shown in the following table: `config.ini' Value Value Used Number of LQH Threads Used 3 2 1 5 or 6 4 2 7 8 4 Setting this parameter outside the permitted range of values causes the management server to abort on startup with the error `Error line NUMBER: Illegal value VALUE for parameter MaxNoOfExecutionThreads'. *Note*: In MySQL Cluster NDB 6.4.0, it is not possible to set `MaxNoOfExecutionThreads' to 2. You can safely use the value 3 instead (it is treated as 2 internally). This issue is resolved in MySQL Cluster NDB 6.4.1. In MySQL Cluster NDB 6.4.0 through 6.4.3, the default value for this parameter was undefined, although the default behavior for *Note `ndbmtd': mysql-cluster-programs-ndbmtd. was to use 1 LQH thread, as though `MaxNoOfExecutionThreads' had been set to 2. Beginning with MySQL Cluster NDB 7.0.4, this parameter has an explcit default value of 2, thus guaranteeing this default behavior. In MySQL Cluster NDB 7.0, it is not possible to cause *Note `ndbmtd': mysql-cluster-programs-ndbmtd. to use more than 1 TC thread, although we plan to introduce this capability in a future MySQL Cluster release series. Like *Note `ndbd': mysql-cluster-programs-ndbd, *Note `ndbmtd': mysql-cluster-programs-ndbmtd. generates a set of log files which are placed in the directory specified by `DataDir' in the `config.ini' configuration file. Except for trace files, these are generated in the same way and have the same names as those generated by *Note `ndbd': mysql-cluster-programs-ndbd. In the event of a critical error, *Note `ndbmtd': mysql-cluster-programs-ndbmtd. generates trace files describing what happened just prior to the error' occurrence. These files, which can be found in the data node's `DataDir', are useful for analysis of problems by the MySQL Cluster Development and Support teams. One trace file is generated for each *Note `ndbmtd': mysql-cluster-programs-ndbmtd. thread. The names of these files have the following pattern: `ndb_NODE_ID_trace.log.TRACE_ID_tTHREAD_ID', In this pattern, NODE_ID stands for the data node's unique node ID in the cluster, TRACE_ID is a trace sequence number, and THREAD_ID is the thread ID. For example, in the event of the failure of an *Note `ndbmtd': mysql-cluster-programs-ndbmtd. process running as a MySQL Cluster data node having the node ID 3 and with `MaxNoOfExecutionThreads' equal to 4, four trace files are generated in the data node's data directory. If the is the first time this node has failed, then these files are named `ndb_3_trace.log.1_t1', `ndb_3_trace.log.1_t2', `ndb_3_trace.log.1_t3', and `ndb_3_trace.log.1_t4'. Internally, these trace files follow the same format as *Note `ndbd': mysql-cluster-programs-ndbd. trace files. The *Note `ndbd': mysql-cluster-programs-ndbd. exit codes and messages that are generated when a data node process shuts down prematurely are also used by *Note `ndbmtd': mysql-cluster-programs-ndbmtd. See `ndbd' Error Messages (http://dev.mysql.com/doc/ndbapi/en/ndbd-error-messages.html), for a listing of these. *Note*: It is possible to use *Note `ndbd': mysql-cluster-programs-ndbd. and *Note `ndbmtd': mysql-cluster-programs-ndbmtd. concurrently on different data nodes in the same MySQL Cluster. However, such configurations have not been tested extensively; thus, we cannot not recommend doing so in a production setting at this time.  File: manual.info, Node: mysql-cluster-programs-ndb-mgmd, Next: mysql-cluster-programs-ndb-mgm, Prev: mysql-cluster-programs-ndbmtd, Up: mysql-cluster-programs 17.4.4 `ndb_mgmd' -- The MySQL Cluster Management Server Daemon --------------------------------------------------------------- The management server is the process that reads the cluster configuration file and distributes this information to all nodes in the cluster that request it. It also maintains a log of cluster activities. Management clients can connect to the management server and check the cluster's status. The following table includes options that are specific to the MySQL Cluster management server program *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. Additional descriptions follow the table. For options common to all MySQL Cluster programs, see *Note mysql-cluster-program-options-common::. *`ndb_mgmd' Command Line Options* Format Description IntroductionDeprecatedRemoved -bind-address Local bind address 5.1.22-ndb-6.2.5, 5.1.22-ndb-6.3.2 -config-cache=valueEnable the management server 5.1.44-ndb-7.0.15, configuration cache; ON by default. 5.1.44-ndb-7.1.4 -c Specify the cluster configuration file; in NDB-6.4.0 and later, needs -reload or -initial to override configuration cache if present -configdir=directorySpecify the cluster management 5.1.30-ndb-6.4.0 server's configuration cache directory -daemon Run ndb_mgmd in daemon mode (default) -initial Causes the management server reload 5.1.30-ndb-6.4.0 its configuration data from the configuration file, bypassing the configuration cache -install[=name]Used to install the management 5.1.47-ndb-7.0.16, server process as a Windows 5.1.47-ndb-7.1.5 service. Does not apply on non-Windows platforms. -interactive Run ndb_mgmd in interactive mode (not officially supported in production; for testing purposes only) -log-name= A name to use when writing messages 5.1.37-ndb-7.0.8 applying to this node in the cluster log. -mycnf Read cluster configuration data from the my.cnf file -no-nodeid-checksDo not provide any node id checks -nodaemon Do not run ndb_mgmd as a daemon -nowait-nodes=listDo not wait for these management 5.1.39-ndb-7.0.10, nodes when starting this 5.1.39-ndb-7.1.0 management server. Also requires -ndb-nodeid to be used. -print-full-configPrint full configuration and exit -reload Causes the management server to 5.1.30-ndb-6.4.0 compare the configuration file with its configuration cache -remove[=name] Used to remove a management server 5.1.47-ndb-7.0.16, process that was previously 5.1.47-ndb-7.1.5 installed as a Windows service, optionally specifying the name of the service to be removed. Does not apply on non-Windows platforms. * `--bind-address=HOST[:PORT]' Options for bind-address *Version Introduced* 5.1.22-ndb-6.2.5, 5.1.22-ndb-6.3.2 *Command-Line `--bind-address' Format* *Permitted Values * *Type* `string' *Default* `[none]' When specified, this option limits management server connections by management clients to clients at the specified host name or IP address (and possibly port, if this is also specified). In such cases, a management client attempting to connect to the management server from any other address fails with the error `Unable to setup port: HOST:PORT!' If the PORT is not specified, the management client attempts to use port 1186. This option was added in MySQL Cluster NDB 6.2.5 and MySQL Cluster NDB 6.3.2. * `--configdir=DIRECTORY' Options for configdir *Version Introduced* 5.1.30-ndb-6.4.0 *Command-Line `--configdir=directory' Format* ** `--config-dir=directory'5.1.37-ndb-7.0.8 *Permitted Values * *Type* `file name' *Default* `$INSTALLDIR/mysql-cluster' Beginning with MySQL Cluster NDB 6.4.0, configuration data is cached internally rather than being read from the cluster global configuration file each time the management server is started (see *Note mysql-cluster-config-file::). This option instructs the management server to its configuration cache in the DIRECTORY indicated. By default, this is a directory named `mysql-cluster' in the MySQL installation directory--for example, if you compile and install MySQL Cluster on a Unix system using the default location, this is `/usr/local/mysql-cluster'. This behavior can be overridden using the `--initial' or `--reload' option for *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. Beginning with MySQL Cluster NDB 7.0.15 and MySQL Cluster NDB 7.1.4, it can also be overridden using the `--config-cache' option. Each of these options is described elsewhere in this section. This option is available beginning with MySQL Cluster NDB 6.4.0. Beginning with MySQL Cluster NDB 7.0.8, `--config-dir' is accepted as an alias for `--configdir'. * This option, whose default value is `1' (or `TRUE', or `ON'), can be used to disable the management server's configuration cache, so that it reads its configuration from `config.ini' every time it starts (see *Note mysql-cluster-config-file::). You can do this by starting the *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. process with any one of the following options: * `--config-cache=0' * `--config-cache=FALSE' * `--config-cache=OFF' * `--skip-config-cache' Using one of the options just listed is effective only if the management server has no stored configuration at the time it is started. If the management server finds any configuration cache files, then the `--config-cache' option or the `--skip-config-cache' option is ignored. Therefore, to disable configuration caching, the option should be used the _first_ time that the management server is started. Otherwise--that is, if you wish to disable configuration caching for a management server that has _already_ created a configuration cache--you must stop the management server, delete any existing configuration cache files manually, then restart the management server with `--skip-config-cache' (or with `--config-cache' set equal to 0, `OFF', or `FALSE'). Configuration cache files are normally created in a directory named `mysql-cluster' under the installation directory (unless this location has been overridden using the `--configdir' option). Each time the management server updates its configuration data, it writes a new cache file. The files are named sequentially in order of creation using the following format: ndb_NODE-ID_config.bin.SEQ-NUMBER NODE-ID is the management server's node ID; SEQ-NUMBER is a sequence number, beginning with 1. For example, if the management server's node ID is 5, then the first three configuration cache files would, when they are created, be named `ndb_5_config.bin.1', `ndb_5_config.bin.2', and `ndb_5_config.bin.3'. If your intent is to purge or reload the configuration cache without actually disabling caching, you should start *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. with one of the options `--reload' or `--initial' instead of `--skip-config-cache'. To re-enable the configuration cache, simply restart the management server, but without the `--config-cache' or `--skip-config-cache' option that was used previously to disable the configuration cache. This option was added in MySQL Cluster NDB 7.0.15 and MySQL Cluster NDB 7.1.4. * `--config-file=FILENAME', `-f FILENAME' Options for config-file *Command-Line `--config-file' Format* ** `-f' ** `-c' *Permitted Values * *Type* `file name' *Default* `./config.ini' Instructs the management server as to which file it should use for its configuration file. By default, the management server looks for a file named `config.ini' in the same directory as the *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. executable; otherwise the file name and location must be specified explicitly. Beginning with MySQL Cluster NDB 6.4.0, this option is ignored unless the management server is forced to read the configuration file, either because *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. was started with the `--reload' or `--initial' option, or because the management server could not find any configuration cache. Beginning with MySQL Cluster NDB 7.0.15 and MySQL Cluster NDB 7.1.4, this option is also read if *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. was started with `--config-cache=OFF'. See *Note mysql-cluster-config-file::, for more information. * `--daemon', `-d' Options for daemon *Command-Line `--daemon' Format* ** `-d' *Permitted Values * *Type* `boolean' *Default* `TRUE' Instructs *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. to start as a daemon process. This is the default behavior. This option has no effect when running *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. on Windows platforms. * `--initial' Options for initial *Version Introduced* 5.1.30-ndb-6.4.0 *Command-Line `--initial' Format* *Permitted Values * *Type* `boolean' *Default* `FALSE' Beginning with MySQL Cluster NDB 6.4.0, configuration data is cached internally rather than being read from the cluster global configuration file each time the management server is started (see *Note mysql-cluster-config-file::). Using this option overrides this behavior, by forcing the management server to delete any existing cache files, and then to re-read the configuration data from the cluster configuration file and to build a new cache. This differs in two ways from the `--reload' option. First, `--reload' forces the server to check the configuration file against the cache and reload its data only if the contents of the file are different from the cache. Second, `--reload' does not delete any existing cache files. If *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. is invoked with `--initial' but cannot find a global configuration file, the management server cannot start. This option was introduced in MySQL Cluster NDB 6.4.0. * `--log-name=NAME' Options for log-name *Version Introduced* 5.1.37-ndb-7.0.8 *Command-Line `--log-name=' Format* *Permitted Values * *Type* `string' *Default* `MgmtSrvr' Provides a name to be used for this node in the cluster log. This option was added in MySQL Cluster NDB 7.0.8. * `--nodaemon' Options for nodaemon *Command-Line `--nodaemon' Format* *Permitted Values * *Type* `boolean' *Default* `FALSE' *Permitted Values * *Type* (windows) `boolean' *Default* `TRUE' Instructs *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. not to start as a daemon process. As of MySQL Cluster NDB 7.0.8, the default behavior for *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. on Windows is to run in the foreground, making this option unnecessary on Windows platforms. (Bug#45588) * `--print-full-config', `-P' Options for print-full-config *Command-Line `--print-full-config' Format* ** `-P' *Permitted Values * *Type* `boolean' *Default* `FALSE' Shows extended information regarding the configuration of the cluster. With this option on the command line the *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. process prints information about the cluster setup including an extensive list of the cluster configuration sections as well as parameters and their values. Normally used together with the `--config-file' (`-f') option. * `--reload' Options for reload *Version Introduced* 5.1.30-ndb-6.4.0 *Command-Line `--reload' Format* *Permitted Values * *Type* `boolean' *Default* `FALSE' Beginning with MySQL Cluster NDB 6.4.0, configuration data is stored internally rather than being read from the cluster global configuration file each time the management server is started (see *Note mysql-cluster-config-file::). Using this option forces the management server to check its internal data store against the cluster configuration file and to reload the configuration if it finds that the configuration file does not match the cache. Existing configuration cache files are preserved, but not used. This differs in two ways from the `--initial' option. First, `--initial' causes all cache files to be deleted. Second, `--initial' forces the management server to re-read the global configuration file and construct a new cache. If the management server cannot find a global configuration file, then the `--reload' option is ignored. This option was introduced in MySQL Cluster NDB 6.4.0. * `--nowait-nodes' Options for nowait-nodes *Version Introduced* 5.1.39-ndb-7.0.10, 5.1.39-ndb-7.1.0 *Command-Line `--nowait-nodes=list' Format* *Permitted Values * *Type* `numeric' *Default* `' *Range* `1-255' When starting a MySQL Cluster is configured with two management nodes and running MySQL Cluster NDB 7.0 and later, each management server normally checks to see whether the other *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. is also operational and whether the other management server's configuration is identical to its own. However, it is sometimes desirable to start the cluster with only one management node (and perhaps to allow the other *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. to be started later). This option causes the management node to bypass any checks for any other management nodes whose node IDs are passed to this option, permitting the cluster to start as though configured to use only the management node that was started. For purposes of illustration, consider the following portion of a `config.ini' file (where we have omitted most of the configuration parameters that are not relevant to this example): [ndbd] NodeId = 1 HostName = 192.168.0.101 [ndbd] NodeId = 2 HostName = 192.168.0.102 [ndbd] NodeId = 3 HostName = 192.168.0.103 [ndbd] NodeId = 4 HostName = 192.168.0.104 [ndb_mgmd] NodeId = 10 HostName = 192.168.0.150 [ndb_mgmd] NodeId = 11 HostName = 192.168.0.151 [api] NodeId = 20 HostName = 192.168.0.200 [api] NodeId = 21 HostName = 192.168.0.201 Assume that you wish to start this cluster using only the management server having node ID `10' and running on the host having the IP address 192.168.0.150. (Suppose, for example, that the host computer on which you intend to the other management server is temporarily unavailable due to a hardware failure, and you are waiting for it to be repaired.) To start the cluster in this way, use a command line on the machine at 192.168.0.150 to enter the following command: shell> ndb_mgmd --ndb-nodeid=10 --nowait-nodes=11 As shown in the preceding example, when using `--nowait-nodes', you must also use the `--ndb-nodeid' option to specify the node ID of this *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. process. You can then start each of the cluster's data nodes in the usual way. If you wish to start and use the second management server in addition to the first management server at a later time without restarting the data nodes, you must start each data node with a connectstring that references both management servers, like this: shell> ndbd -c 192.168.0.150,192.168.0.151 The same is true with regard to the connectstring used with any *Note `mysqld': mysqld. processes that you wish to start as MySQL Cluster SQL nodes connected to this cluster. See *Note mysql-cluster-connectstring::, for more information. When used with *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd, this option affects the behavior of the management node with regard to other management nodes only. Do not confuse it with the `--nowait-nodes' option used with *Note `ndbd': mysql-cluster-programs-ndbd. (or *Note `ndbmtd': mysql-cluster-programs-ndbmtd. in MySQL Cluster NDB 7.0 and later) to permit a cluster to start with fewer than its full complement of data nodes; when used with data nodes, this option affects their behavior only with regard to other data nodes. Multiple management node IDs may be passed to this option as a comma-separated list. Each node ID must be no less than 1 and no greater than 255. In practice, it is quite rare to use more than two management servers for the same MySQL Cluster (or to have any need for doing so); in most cases you need to pass to this option only the single node ID for the one management server that you do not wish to use when starting the cluster. *Note*: When you later start the `missing' management server, its configuration must match that of the management server that is already in use by the cluster. Otherwise, it fails the configuration check performed by the existing management server, and does not start. This option was introduced in MySQL Cluster NDB 7.0.10 and MySQL Cluster NDB 7.1.0. It is not strictly necessary to specify a connectstring when starting the management server. However, if you are using more than one management server, a connectstring should be provided and each node in the cluster should specify its node ID explicitly. See *Note mysql-cluster-connectstring::, for information about using connectstrings. *Note mysql-cluster-programs-ndb-mgmd::, describes other options for *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. The following files are created or used by *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. in its starting directory, and are placed in the `DataDir' as specified in the `config.ini' configuration file. In the list that follows, NODE_ID is the unique node identifier. * `config.ini' is the configuration file for the cluster as a whole. This file is created by the user and read by the management server. *Note mysql-cluster-configuration::, discusses how to set up this file. * `ndb_NODE_ID_cluster.log' is the cluster events log file. Examples of such events include checkpoint startup and completion, node startup events, node failures, and levels of memory usage. A complete listing of cluster events with descriptions may be found in *Note mysql-cluster-management::. When the size of the cluster log reaches one million bytes, the file is renamed to `ndb_NODE_ID_cluster.log.SEQ_ID', where SEQ_ID is the sequence number of the cluster log file. (For example: If files with the sequence numbers 1, 2, and 3 already exist, the next log file is named using the number `4'.) * `ndb_NODE_ID_out.log' is the file used for `stdout' and `stderr' when running the management server as a daemon. * `ndb_NODE_ID.pid' is the process ID file used when running the management server as a daemon. * `--install[=NAME]' Options for install *Version Introduced* 5.1.47-ndb-7.0.16, 5.1.47-ndb-7.1.5 *Command-Line `--install[=name]' Format* *Permitted Values * *Type* (windows) `string' *Default* `ndb_mgmd' Causes *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. to be installed as a Windows service. Optionally, you can specify a name for the service; if not set, the service name defaults to `ndb_mgmd'. Although it is preferable to specify other *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. program options in a `my.ini' or `my.cnf' configuration file, it is possible to use them together with `--install'. However, in such cases, the `--install' option must be specified first, before any other options are given, for the Windows service installation to succeed. It is generally not advisable to use this option together with the `--initial' option, since this causes the configuration cache to be wiped and rebuilt every time the service is stopped and started. Care should also be taken if you intend to use any other *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. options that affect the starting of the management server, and you should make absolutely certain you fully understand and allow for any possible consequences of doing so. The `--install' option has no effect on non-Windows platforms. This option became available in MySQL Cluster NDB 7.0.16 and MySQL Cluster NDB 7.1.5. * `--remove[=NAME]' Options for remove *Version Introduced* 5.1.47-ndb-7.0.16, 5.1.47-ndb-7.1.5 *Command-Line `--remove[=name]' Format* *Permitted Values * *Type* (windows) `string' *Default* `ndb_mgmd' Causes an *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. process that was previously installed as a Windows service to be removed. Optionally, you can specify a name for the service to be uninstalled; if not set, the service name defaults to `ndb_mgmd'. The `--remove' option has no effect on non-Windows platforms. This option became available in MySQL Cluster NDB 7.0.16 and MySQL Cluster NDB 7.1.5.  File: manual.info, Node: mysql-cluster-programs-ndb-mgm, Next: mysql-cluster-programs-ndb-config, Prev: mysql-cluster-programs-ndb-mgmd, Up: mysql-cluster-programs 17.4.5 `ndb_mgm' -- The MySQL Cluster Management Client ------------------------------------------------------- The *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. management client process is actually not needed to run the cluster. Its value lies in providing a set of commands for checking the cluster's status, starting backups, and performing other administrative functions. The management client accesses the management server using a C API. Advanced users can also employ this API for programming dedicated management processes to perform tasks similar to those performed by *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. To start the management client, it is necessary to supply the host name and port number of the management server: shell> ndb_mgm [HOST_NAME [PORT_NUM]] For example: shell> ndb_mgm ndb_mgmd.mysql.com 1186 The default host name and port number are `localhost' and 1186, respectively. The following table includes options that are specific to the MySQL Cluster management client program *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. Additional descriptions follow the table. For options common to all MySQL Cluster programs, see *Note mysql-cluster-program-options-common::. *`ndb_mgm' Command Line Options* Format Description IntroductionDeprecatedRemoved -execute=name Execute command and exit -try-reconnect=#Specify number of tries for connecting to ndb_mgmd (0 = infinite) * `--execute=`command'', `-e `command'' Options for execute *Command-Line `--execute=name' Format* ** `-e' This option can be used to send a command to the MySQL Cluster management client from the system shell. For example, either of the following is equivalent to executing `SHOW' in the management client: shell> ndb_mgm -e "SHOW" shell> ndb_mgm --execute="SHOW" This is analogous to how the `--execute' or `-e' option works with the *Note `mysql': mysql. command-line client. See *Note command-line-options::. *Note*: If the management client command to be passed using this option contains any space characters, then the command _must_ be enclosed in quotation marks. Either single or double quotation marks may be used. If the management client command contains no space characters, the quotation marks are optional. * `--try-reconnect=NUMBER' Options for try-reconnect *Command-Line `--try-reconnect=#' Format* ** `-t' *Permitted Values * *Type* `boolean' *Default* `TRUE' If the connection to the management server is broken, the node tries to reconnect to it every 5 seconds until it succeeds. By using this option, it is possible to limit the number of attempts to NUMBER before giving up and reporting an error instead. Additional information about using *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. can be found in *Note mysql-cluster-mgm-client-commands::.  File: manual.info, Node: mysql-cluster-programs-ndb-config, Next: mysql-cluster-programs-ndb-cpcd, Prev: mysql-cluster-programs-ndb-mgm, Up: mysql-cluster-programs 17.4.6 `ndb_config' -- Extract MySQL Cluster Configuration Information ---------------------------------------------------------------------- This tool extracts current configuration information for data nodes, SQL nodes, and API nodes from a cluster management node (and possibly its `config.ini' file). Beginning with MySQL Cluster NDB 6.3.25 and MySQL Cluster NDB 7.0.6, it can also provide an offline dump (in text or XML format) of all configuration parameters which can be used, along with their default, maximum, and minimum values and other information (see the discussion of the `--configinfo' and `--xml' options later in this section). The following table includes options that are specific to *Note `ndb_config': mysql-cluster-programs-ndb-config. Additional descriptions follow the table. For options common to all MySQL Cluster programs, see *Note mysql-cluster-program-options-common::. *`ndb_config' Command Line Options* Format Description IntroductionDeprecatedRemoved -configinfo Dumps information about all NDB 5.1.34-ndb-6.3.25, configuration parameters in text 5.1.34-ndb-7.0.6 format with default, maximum, and minimum values. Use with -xml to obtain XML output. -connections Print connection information only -fields=string Field separator -host=name Specify host -mycnf Read configuration data from my.cnf file -nodeid Get configuration of node with this ID -nodes Print node information only Short form for -ndb-connectstring 5.1.12 -config-file=pathSet the path to config.ini file -query=string One or more query options (attributes) -rows=string Row separator -type=name Specify node type -configinfo Use with -configinfo to obtain a 5.1.34-ndb-6.3.25, -xml dump of all NDB configuration 5.1.34-ndb-7.0.6 parameters in XML format with default, maximum, and minimum values. * `--usage', `--help', or `-?' Options for help *Command-Line `--help' Format* ** `--usage' ** `-?' Causes *Note `ndb_config': mysql-cluster-programs-ndb-config. to print a list of available options, and then exit. * `--version', `-V' Options for version *Command-Line `-V' Format* ** `--version' Causes *Note `ndb_config': mysql-cluster-programs-ndb-config. to print a version information string, and then exit. * `--ndb-connectstring=CONNECT_STRING' Options for connectstring *Command-Line `--ndb-connectstring=name' Format* ** `--connect-string=name' ** `-c' *Permitted Values * *Type* `string' *Default* `localhost:1186' Specifies the connectstring to use in connecting to the management server. The format for the connectstring is the same as described in *Note mysql-cluster-connectstring::, and defaults to `localhost:1186'. The use of `-c' as a short version for this option is supported for *Note `ndb_config': mysql-cluster-programs-ndb-config. beginning with MySQL 5.1.12. * `--config-file=PATH-TO-FILE' Gives the path to the management server's configuration file (`config.ini'). This may be a relative or absolute path. If the management node resides on a different host from the one on which *Note `ndb_config': mysql-cluster-programs-ndb-config. is invoked, then an absolute path must be used. * `--query=QUERY-OPTIONS', `-q' QUERY-OPTIONS Options for query *Command-Line `--query=string' Format* ** `-q' *Permitted Values * *Type* `string' *Default* `' This is a comma-delimited list of _query options_--that is, a list of one or more node attributes to be returned. These include `id' (node ID), type (node type--that is, `ndbd', `mysqld', or `ndb_mgmd'), and any configuration parameters whose values are to be obtained. For example, `--query=id,type,indexmemory,datamemory' returns the node ID, node type, `DataMemory', and `IndexMemory' for each node. *Note*: If a given parameter is not applicable to a certain type of node, than an empty string is returned for the corresponding value. See the examples later in this section for more information. * `--host=HOSTNAME' Options for host *Command-Line `--host=name' Format* *Permitted Values * *Type* `string' *Default* `' Specifies the host name of the node for which configuration information is to be obtained. *Note*: While the hostname `localhost' usually resolves to the IP address `127.0.0.1', this may not necessarily be true for all operating platforms and configurations. This means that it is possible, when `localhost' is used in `config.ini', for *Note `ndb_config `--host=localhost'': mysql-cluster-programs-ndb-config. to fail if *Note `ndb_config': mysql-cluster-programs-ndb-config. is run on a different host where `localhost' resolves to a different address (for example, on some versions of SUSE Linux, this is `127.0.0.2'). In general, for best results, you should use numeric IP addresses for all MySQL Clustewr configuration values relating to hosts, or verify that all MySQL Cluster hosts handle `localhost' in the same fashion. * `--id=NODE_ID', `--nodeid=NODE_ID' Either of these options can be used to specify the node ID of the node for which configuration information is to be obtained. `--nodeid' is the preferred form. * `--nodes' Options for nodes *Command-Line `--nodes' Format* *Permitted Values * *Type* `boolean' *Default* `FALSE' Tells *Note `ndb_config': mysql-cluster-programs-ndb-config. to print information from parameters defined in `[ndbd]' sections only. Currently, using this option has no affect, since these are the only values checked, but it may become possible in future to query parameters set in `[tcp]' and other sections of cluster configuration files. * `--type=NODE_TYPE' Options for type *Command-Line `--type=name' Format* *Permitted Values * *Type* `enumeration' *Default* `' *Valid Values* `ndbd' `mysqld' `ndb_mgmd' Filters results so that only configuration values applying to nodes of the specified NODE_TYPE (`ndbd', `mysqld', or `ndb_mgmd') are returned. * `--fields=DELIMITER', `-f' DELIMITER Options for fields *Command-Line `--fields=string' Format* ** `-f' *Permitted Values * *Type* `string' *Default* `' Specifies a DELIMITER string used to separate the fields in the result. The default is ``,'' (the comma character). *Note*: If the DELIMITER contains spaces or escapes (such as `\n' for the linefeed character), then it must be quoted. * `--rows=SEPARATOR', `-r' SEPARATOR Options for rows *Command-Line `--rows=string' Format* ** `-r' *Permitted Values * *Type* `string' *Default* `' Specifies a SEPARATOR string used to separate the rows in the result. The default is a space character. *Note*: If the SEPARATOR contains spaces or escapes (such as `\n' for the linefeed character), then it must be quoted. * `--configinfo' The `--configinfo' option, added in MySQL Cluster NDB 6.3.25 and MySQL Cluster NDB 7.0.6, causes *Note `ndb_config': mysql-cluster-programs-ndb-config. to dump a list of each MySQL Cluster configuration parameter supported by the MySQL Cluster distribution of which *Note `ndb_config': mysql-cluster-programs-ndb-config. is a part, including the following information: * A brief description of each parameter's purpose, effects, and usage * The section of the `config.ini' file where the parameter may be used * The parameter's data type or unit of measurement * Where applicable, the parameter's default, minimum, and maximum values * A brief description of the parameter's purpose, effects, and usage * MySQL Cluster release version and build information By default, this output is in text format. Part of this output is shown here: shell> ndb_config --configinfo ****** SYSTEM ****** Name (String) Name of system (NDB Cluster) MANDATORY PrimaryMGMNode (Non-negative Integer) Node id of Primary ndb_mgmd(MGM) node Default: 0 (Min: 0, Max: 4294967039) ConfigGenerationNumber (Non-negative Integer) Configuration generation number Default: 0 (Min: 0, Max: 4294967039) ****** DB ****** MaxNoOfSubscriptions (Non-negative Integer) Max no of subscriptions (default 0 == MaxNoOfTables) Default: 0 (Min: 0, Max: 4294967039) MaxNoOfSubscribers (Non-negative Integer) Max no of subscribers (default 0 == 2 * MaxNoOfTables) Default: 0 (Min: 0, Max: 4294967039) ... `--configinfo' `--xml' Options for xml *Version Introduced* 5.1.34-ndb-6.3.25, 5.1.34-ndb-7.0.6 *Command-Line `--configinfo Format* --xml' *Permitted Values * *Type* `boolean' *Default* `false' You can obtain the output of *Note `ndb_config': mysql-cluster-programs-ndb-config. `--configinfo' as XML by adding the `--xml' option (like the `--configinfo' option, available beginning with MySQL Cluster NDB 6.3.25 and MySQL Cluster NDB 7.0.6). A portion of the resulting output is shown in this example: shell> ndb_config --configinfo --xml
...
... *Note*: Normally, the XML output produced by *Note `ndb_config': mysql-cluster-programs-ndb-config. `--configinfo' `--xml' is formatted using one line per element; we have added extra whitespace in the previous example, as well as the next one, for reasons of legibility. This should not make any difference to applications using this output, since most XML processors either ignore nonessential whitespace as a matter of course, or can be instructed to do so. Beginning with MySQL Cluster NDB 6.3.29 and MySQL Cluster NDB 7.0.10, the XML output also indicates when changing a given parameter requires that data nodes be restarted using the `--initial' option. This is shown by the presence of an `initial="true"' attribute in the corresponding `' element. In addition (also beginning with MySQL Cluster NDB 6.3.29 and MySQL Cluster NDB 7.0.10), the restart type (`system' or `node') is also shown; if a given parameter requires a system restart, this is indicated by the presence of a `restart="system"' attribute in the corresponding `' element. For example, changing the value set for the `Diskless' parameter requires a system initial restart, as shown here (with the `restart' and `initial' attributes highlighted for visibility): Currently, no `initial' attribute is included in the XML output for `' elements corresponding to parameters which do not require initial restarts; in other words, `initial="false"' is the default, and the value `false' should be assumed if the attribute is not present. Similarly, the default restart type is `node' (that is, an online or `rolling' restart of the cluster), but the `restart' attribute is included only if the restart type is `system' (meaning that all cluster nodes must be shut down at the same time, then restarted). *Important*: The `--xml' option can be used only with the `--configinfo' option. Using `--xml' without `--configinfo' fails with an error. Unlike the options used with this program to obtain current configuration data, `--configinfo' and `--xml' use information obtained from the MySQL Cluster sources when *Note `ndb_config': mysql-cluster-programs-ndb-config. was compiled. For this reason, no connection to a running MySQL Cluster or access to a `config.ini' or `my.cnf' file is required for these two options. Combining other *Note `ndb_config': mysql-cluster-programs-ndb-config. options (such as `--query' or `--type') with `--configinfo' or `--xml' is not supported. Currently, if you attempt to do so, the usual result is that all other options besides `--configinfo' or `--xml' are simply ignored. _However, this behavior is not guaranteed and is subject to change at any time_. In addition, since *Note `ndb_config': mysql-cluster-programs-ndb-config, when used with the `--configinfo' option, does not access the MySQL Cluster or read any files, trying to specify additional options such as `--ndb-connectstring' or `--config-file' with `--configinfo' serves no purpose. * Examples * 1. To obtain the node ID and type of each node in the cluster: shell> ./ndb_config --query=id,type --fields=':' --rows='\n' 1:ndbd 2:ndbd 3:ndbd 4:ndbd 5:ndb_mgmd 6:mysqld 7:mysqld 8:mysqld 9:mysqld In this example, we used the `--fields' options to separate the ID and type of each node with a colon character (`:'), and the `--rows' options to place the values for each node on a new line in the output. 2. To produce a connectstring that can be used by data, SQL, and API nodes to connect to the management server: shell> ./ndb_config --config-file=usr/local/mysql/cluster-data/config.ini --query=hostname,portnumber --fields=: --rows=, --type=ndb_mgmd 192.168.0.179:1186 3. This invocation of *Note `ndb_config': mysql-cluster-programs-ndb-config. checks only data nodes (using the `--type' option), and shows the values for each node's ID and host name, as well as the values set for its `DataMemory', `IndexMemory', and `DataDir' parameters: shell> ./ndb_config --type=ndbd --query=id,host,datamemory,indexmemory,datadir -f ' : ' -r '\n' 1 : 192.168.0.193 : 83886080 : 18874368 : /usr/local/mysql/cluster-data 2 : 192.168.0.112 : 83886080 : 18874368 : /usr/local/mysql/cluster-data 3 : 192.168.0.176 : 83886080 : 18874368 : /usr/local/mysql/cluster-data 4 : 192.168.0.119 : 83886080 : 18874368 : /usr/local/mysql/cluster-data In this example, we used the short options `-f' and `-r' for setting the field delimiter and row separator, respectively. 4. To exclude results from any host except one in particular, use the `--host' option: shell> ./ndb_config --host=192.168.0.176 -f : -r '\n' -q id,type 3:ndbd 5:ndb_mgmd In this example, we also used the short form `-q' to determine the attributes to be queried. Similarly, you can limit results to a node with a specific ID using the `--id' or `--nodeid' option.  File: manual.info, Node: mysql-cluster-programs-ndb-cpcd, Next: mysql-cluster-programs-ndb-delete-all, Prev: mysql-cluster-programs-ndb-config, Up: mysql-cluster-programs 17.4.7 `ndb_cpcd' -- Automate Testing for NDB Development --------------------------------------------------------- This utility is found in the `libexec' directory. It is part of an internal automated test framework used in testing and debugging MySQL Cluster. Because it can control processes on remote systems, it is not advisable to use *Note `ndb_cpcd': mysql-cluster-programs-ndb-cpcd. in a production cluster. The source files for *Note `ndb_cpcd': mysql-cluster-programs-ndb-cpcd. may be found in the directory `storage/ndb/src/cw/cpcd', in the MySQL Cluster source tree.  File: manual.info, Node: mysql-cluster-programs-ndb-delete-all, Next: mysql-cluster-programs-ndb-desc, Prev: mysql-cluster-programs-ndb-cpcd, Up: mysql-cluster-programs 17.4.8 `ndb_delete_all' -- Delete All Rows from an NDB Table ------------------------------------------------------------ *Note `ndb_delete_all': mysql-cluster-programs-ndb-delete-all. deletes all rows from the given *Note `NDB': mysql-cluster. table. In some cases, this can be much faster than *Note `DELETE': delete. or even *Note `TRUNCATE TABLE': truncate-table. * Usage * ndb_delete_all -c CONNECT_STRING TBL_NAME -d DB_NAME This deletes all rows from the table named TBL_NAME in the database named DB_NAME. It is exactly equivalent to executing `TRUNCATE DB_NAME.TBL_NAME' in MySQL. * Additional Options * * `--transactional', `-t' Use of this option causes the delete operation to be performed as a single transaction. *Warning*: With very large tables, using this option may cause the number of operations available to the cluster to be exceeded.  File: manual.info, Node: mysql-cluster-programs-ndb-desc, Next: mysql-cluster-programs-ndb-drop-index, Prev: mysql-cluster-programs-ndb-delete-all, Up: mysql-cluster-programs 17.4.9 `ndb_desc' -- Describe NDB Tables ---------------------------------------- *Note `ndb_desc': mysql-cluster-programs-ndb-desc. provides a detailed description of one or more *Note `NDB': mysql-cluster. tables. * Usage * ndb_desc -c CONNECT_STRING TBL_NAME -d DB_NAME [-p] * Sample Output * MySQL table creation and population statements: USE test; CREATE TABLE fish ( id INT(11) NOT NULL AUTO_INCREMENT, name VARCHAR(20) NOT NULL, length_mm INT(11) NOT NULL, weight_gm INT(11) NOT NULL, PRIMARY KEY pk (id), UNIQUE KEY uk (name) ) ENGINE=NDB; INSERT INTO fish VALUES ('','guppy', 35, 2), ('','tuna', 2500, 150000), ('','shark', 3000, 110000), ('','manta ray', 1500, 50000), ('','grouper', 900, 125000), ('','puffer', 250, 2500); Output from *Note `ndb_desc': mysql-cluster-programs-ndb-desc.: shell> ./ndb_desc -c localhost fish -d test -p -- fish -- Version: 2 Fragment type: 9 K Value: 6 Min load factor: 78 Max load factor: 80 Temporary table: no Number of attributes: 4 Number of primary keys: 1 Length of frm data: 311 Row Checksum: 1 Row GCI: 1 SingleUserMode: 0 ForceVarPart: 1 FragmentCount: 2 TableStatus: Retrieved -- Attributes -- id Int PRIMARY KEY DISTRIBUTION KEY AT=FIXED ST=MEMORY AUTO_INCR name Varchar(20;latin1_swedish_ci) NOT NULL AT=SHORT_VAR ST=MEMORY length_mm Int NOT NULL AT=FIXED ST=MEMORY weight_gm Int NOT NULL AT=FIXED ST=MEMORY -- Indexes -- PRIMARY KEY(id) - UniqueHashIndex PRIMARY(id) - OrderedIndex uk$unique(name) - UniqueHashIndex uk(name) - OrderedIndex -- Per partition info -- Partition Row count Commit count Frag fixed memory Frag varsized memory Extent_space Free extent_space 0 2 2 32768 32768 0 0 1 4 4 32768 32768 0 0 NDBT_ProgramExit: 0 - OK Information about multiple tables can be obtained in a single invocation of *Note `ndb_desc': mysql-cluster-programs-ndb-desc. by using their names, separated by spaces. All of the tables must be in the same database. The `Extent_space' and `Free extent_space' columns were added in MySQL Cluster NDB 6.3.27 and MySQL Cluster NDB 7.0.8. They are applicable only to `NDB' tables having columns on disk; for tables having only in-memory columns, these columns always contain the value `0'. To illustrate their use, we modify the previous example. First, we must create the necessary Disk Data objects, as shown here: CREATE LOGFILE GROUP lg_1 ADD UNDOFILE 'undo_1.log' INITIAL_SIZE 16M UNDO_BUFFER_SIZE 2M ENGINE NDB; ALTER LOGFILE GROUP lg_1 ADD UNDOFILE 'undo_2.log' INITIAL_SIZE 12M ENGINE NDB; CREATE TABLESPACE ts_1 ADD DATAFILE 'data_1.dat' USE LOGFILE GROUP lg_1 INITIAL_SIZE 32M ENGINE NDB; ALTER TABLESPACE ts_1 ADD DATAFILE 'data_2.dat' INITIAL_SIZE 48M ENGINE NDB; (For more information on the statements just shown and the objects created by them, see *Note mysql-cluster-disk-data-objects::, as well as *Note create-logfile-group::, and *Note create-tablespace::.) Now we can create and populate a version of the `fish' table that stores 2 of its columns on disk (deleting the previous version of the table first, if it already exists): CREATE TABLE fish ( id INT(11) NOT NULL AUTO_INCREMENT, name VARCHAR(20) NOT NULL, length_mm INT(11) NOT NULL, weight_gm INT(11) NOT NULL, PRIMARY KEY pk (id), UNIQUE KEY uk (name) ) TABLESPACE ts_1 STORAGE DISK ENGINE=NDB; INSERT INTO fish VALUES ('','guppy', 35, 2), ('','tuna', 2500, 150000), ('','shark', 3000, 110000), ('','manta ray', 1500, 50000), ('','grouper', 900, 125000), ('','puffer', 250, 2500); When run against this version of the table, *Note `ndb_desc': mysql-cluster-programs-ndb-desc. displays the following output: shell> ./ndb_desc -c localhost fish -d test -p -- fish -- Version: 3 Fragment type: 9 K Value: 6 Min load factor: 78 Max load factor: 80 Temporary table: no Number of attributes: 4 Number of primary keys: 1 Length of frm data: 321 Row Checksum: 1 Row GCI: 1 SingleUserMode: 0 ForceVarPart: 1 FragmentCount: 2 TableStatus: Retrieved -- Attributes -- id Int PRIMARY KEY DISTRIBUTION KEY AT=FIXED ST=MEMORY AUTO_INCR name Varchar(20;latin1_swedish_ci) NOT NULL AT=SHORT_VAR ST=MEMORY length_mm Int NOT NULL AT=FIXED ST=DISK weight_gm Int NOT NULL AT=FIXED ST=DISK -- Indexes -- PRIMARY KEY(id) - UniqueHashIndex PRIMARY(id) - OrderedIndex uk$unique(name) - UniqueHashIndex uk(name) - OrderedIndex -- Per partition info -- Partition Row count Commit count Frag fixed memory Frag varsized memory Extent_space Free extent_space 0 2 2 32768 32768 1048576 1044440 1 4 4 32768 32768 1048576 1044400 NDBT_ProgramExit: 0 - OK This means that 1048576 bytes are allocated from the tablespace for this table on each partition, of which 1044440 bytes remain free for additional storage. In other words, 1048576 - 1044440 = 4136 bytes per partition is currently being used to store the data from this table's disk-based columns. The number of bytes shown as `Free extent_space' is available for storing on-disk column data from the `fish' table only; for this reason, it is not visible when selecting from the *Note `INFORMATION_SCHEMA.FILES': files-table. table. * Additional Options * * `--extra-partition-info', `-p' Print additional information about the table's partitions. * `--blob-info', `-b' Include information about subordinate *Note `BLOB': blob. and *Note `TEXT': blob. columns. Use of this option also requires the use of the `--extra-partition-info' (`-p') option. This option was added in MySQL Cluster NDB 6.3.32, MySQL Cluster NDB 7.0.13, and MySQL Cluster NDB 7.1.2. * `--extra-node-info', `-n' Include information about the mappings between table partitions and the data nodes upon which they reside. This information can be useful for verifying distribution awareness mechanisms and supporting more efficient application access to the data stored in MySQL Cluster. Use of this option also requires the use of the `--extra-partition-info' (`-p') option. This option was added in MySQL Cluster NDB 6.2.19, MySQL Cluster NDB 6.3.33, MySQL Cluster NDB 7.0.14, and MySQL Cluster NDB 7.1.2.  File: manual.info, Node: mysql-cluster-programs-ndb-drop-index, Next: mysql-cluster-programs-ndb-drop-table, Prev: mysql-cluster-programs-ndb-desc, Up: mysql-cluster-programs 17.4.10 `ndb_drop_index' -- Drop Index from an NDB Table -------------------------------------------------------- *Note `ndb_drop_index': mysql-cluster-programs-ndb-drop-index. drops the specified index from an *Note `NDB': mysql-cluster. table. _It is recommended that you use this utility only as an example for writing NDB API applications_--see the Warning later in this section for details. * Usage * ndb_drop_index -c CONNECT_STRING TABLE_NAME INDEX -d DB_NAME The statement shown above drops the index named INDEX from the TABLE in the DATABASE. * Additional Options * None that are specific to this application. *Warning*: _Operations performed on Cluster table indexes using the NDB API are not visible to MySQL and make the table unusable by a MySQL server_. If you use this program to drop an index, then try to access the table from an SQL node, an error results, as shown here: shell> ./ndb_drop_index -c localhost dogs ix -d ctest1 Dropping index dogs/idx...OK NDBT_ProgramExit: 0 - OK shell> ./mysql -u jon -p ctest1 Enter password: ******* Reading table information for completion of table and column names You can turn off this feature to get a quicker startup with -A Welcome to the MySQL monitor. Commands end with ; or \g. Your MySQL connection id is 7 to server version: 5.1.56-ndb-7.1.16 Type 'help;' or '\h' for help. Type '\c' to clear the buffer. mysql> SHOW TABLES; +------------------+ | Tables_in_ctest1 | +------------------+ | a | | bt1 | | bt2 | | dogs | | employees | | fish | +------------------+ 6 rows in set (0.00 sec) mysql> SELECT * FROM dogs; `ERROR 1296 (HY000): Got error 4243 'Index not found' from NDBCLUSTER' In such a case, your _only_ option for making the table available to MySQL again is to drop the table and re-create it. You can use either the SQL statement*Note `DROP TABLE': drop-table. or the *Note `ndb_drop_table': mysql-cluster-programs-ndb-drop-table. utility (see *Note mysql-cluster-programs-ndb-drop-table::) to drop the table.  File: manual.info, Node: mysql-cluster-programs-ndb-drop-table, Next: mysql-cluster-programs-ndb-error-reporter, Prev: mysql-cluster-programs-ndb-drop-index, Up: mysql-cluster-programs 17.4.11 `ndb_drop_table' -- Drop an NDB Table --------------------------------------------- *Note `ndb_drop_table': mysql-cluster-programs-ndb-drop-table. drops the specified *Note `NDB': mysql-cluster. table. (If you try to use this on a table created with a storage engine other than *Note `NDB': mysql-cluster, the attempt fails with the error `723: No such table exists'.) This operation is extremely fast; in some cases, it can be an order of magnitude faster than using a MySQL *Note `DROP TABLE': drop-table. statement on an *Note `NDB': mysql-cluster. table. * Usage * ndb_drop_table -c CONNECT_STRING TBL_NAME -d DB_NAME * Additional Options * None.  File: manual.info, Node: mysql-cluster-programs-ndb-error-reporter, Next: mysql-cluster-programs-ndb-print-backup-file, Prev: mysql-cluster-programs-ndb-drop-table, Up: mysql-cluster-programs 17.4.12 `ndb_error_reporter' -- NDB Error-Reporting Utility ----------------------------------------------------------- *Note `ndb_error_reporter': mysql-cluster-programs-ndb-error-reporter. creates an archive from data node and management node log files that can be used to help diagnose bugs or other problems with a cluster. _It is highly recommended that you make use of this utility when filing reports of bugs in MySQL Cluster_. * Usage * ndb_error_reporter PATH/TO/CONFIG-FILE [USERNAME] [--fs] This utility is intended for use on a management node host, and requires the path to the management host configuration file (`config.ini'). Optionally, you can supply the name of a user that is able to access the cluster's data nodes using SSH, to copy the data node log files. ndb_error_reporter then includes all of these files in archive that is created in the same directory in which it is run. The archive is named `ndb_error_report_YYYYMMDDHHMMSS.tar.bz2', where YYYYMMDDHHMMSS is a datetime string. If the `--fs' is used, then the data node file systems are also copied to the management host and included in the archive that is produced by this script. As data node file systems can be extremely large even after being compressed, we ask that you please do _not_ send archives created using this option to Oracle unless you are specifically requested to do so. Options for fs *Command-Line Format* `--fs' *Permitted Values * *Type* `boolean' *Default* `FALSE'  File: manual.info, Node: mysql-cluster-programs-ndb-print-backup-file, Next: mysql-cluster-programs-ndb-print-schema-file, Prev: mysql-cluster-programs-ndb-error-reporter, Up: mysql-cluster-programs 17.4.13 `ndb_print_backup_file' -- Print NDB Backup File Contents ----------------------------------------------------------------- *Note `ndb_print_backup_file': mysql-cluster-programs-ndb-print-backup-file. obtains diagnostic information from a cluster backup file. * Usage * ndb_print_backup_file FILE_NAME FILE_NAME is the name of a cluster backup file. This can be any of the files (`.Data', `.ctl', or `.log' file) found in a cluster backup directory. These files are found in the data node's backup directory under the subdirectory `BACKUP-#', where # is the sequence number for the backup. For more information about cluster backup files and their contents, see *Note mysql-cluster-backup-concepts::. Like *Note `ndb_print_schema_file': mysql-cluster-programs-ndb-print-schema-file. and *Note `ndb_print_sys_file': mysql-cluster-programs-ndb-print-sys-file. (and unlike most of the other *Note `NDB': mysql-cluster. utilities that are intended to be run on a management server host or to connect to a management server) *Note `ndb_print_backup_file': mysql-cluster-programs-ndb-print-backup-file. must be run on a cluster data node, since it accesses the data node file system directly. Because it does not make use of the management server, this utility can be used when the management server is not running, and even when the cluster has been completely shut down. * Additional Options * None.  File: manual.info, Node: mysql-cluster-programs-ndb-print-schema-file, Next: mysql-cluster-programs-ndb-print-sys-file, Prev: mysql-cluster-programs-ndb-print-backup-file, Up: mysql-cluster-programs 17.4.14 `ndb_print_schema_file' -- Print NDB Schema File Contents ----------------------------------------------------------------- *Note `ndb_print_schema_file': mysql-cluster-programs-ndb-print-schema-file. obtains diagnostic information from a cluster schema file. * Usage * ndb_print_schema_file FILE_NAME FILE_NAME is the name of a cluster schema file. For more information about cluster schema files, see Cluster Data Node `FileSystemDir' Files (http://dev.mysql.com/doc/ndbapi/en/ndb-internals-ndbd-filesystemdir-files.html). Like *Note `ndb_print_backup_file': mysql-cluster-programs-ndb-print-backup-file. and *Note `ndb_print_sys_file': mysql-cluster-programs-ndb-print-sys-file. (and unlike most of the other *Note `NDB': mysql-cluster. utilities that are intended to be run on a management server host or to connect to a management server) `ndb_schema_backup_file' must be run on a cluster data node, since it accesses the data node file system directly. Because it does not make use of the management server, this utility can be used when the management server is not running, and even when the cluster has been completely shut down. * Additional Options * None.  File: manual.info, Node: mysql-cluster-programs-ndb-print-sys-file, Next: mysql-cluster-programs-ndbd-redo-log-reader, Prev: mysql-cluster-programs-ndb-print-schema-file, Up: mysql-cluster-programs 17.4.15 `ndb_print_sys_file' -- Print NDB System File Contents -------------------------------------------------------------- *Note `ndb_print_sys_file': mysql-cluster-programs-ndb-print-sys-file. obtains diagnostic information from a MySQL Cluster system file. * Usage * ndb_print_sys_file FILE_NAME FILE_NAME is the name of a cluster system file (sysfile). Cluster system files are located in a data node's data directory (`DataDir'); the path under this directory to system files matches the pattern `ndb_#_fs/D#/DBDIH/P#.sysfile'. In each case, the # represents a number (not necessarily the same number). For more information, see Cluster Data Node `FileSystemDir' Files (http://dev.mysql.com/doc/ndbapi/en/ndb-internals-ndbd-filesystemdir-files.html). Like *Note `ndb_print_backup_file': mysql-cluster-programs-ndb-print-backup-file. and *Note `ndb_print_schema_file': mysql-cluster-programs-ndb-print-schema-file. (and unlike most of the other *Note `NDB': mysql-cluster. utilities that are intended to be run on a management server host or to connect to a management server) *Note `ndb_print_backup_file': mysql-cluster-programs-ndb-print-backup-file. must be run on a cluster data node, since it accesses the data node file system directly. Because it does not make use of the management server, this utility can be used when the management server is not running, and even when the cluster has been completely shut down. * Additional Options * None.  File: manual.info, Node: mysql-cluster-programs-ndbd-redo-log-reader, Next: mysql-cluster-programs-ndb-restore, Prev: mysql-cluster-programs-ndb-print-sys-file, Up: mysql-cluster-programs 17.4.16 `ndbd_redo_log_reader' -- Check and Print Content of Cluster Redo Log ----------------------------------------------------------------------------- Reads a redo log file, checking it for errors, printing its contents in a human-readable format, or both. *Note `ndbd_redo_log_reader': mysql-cluster-programs-ndbd-redo-log-reader. is intended for use primarily by MySQL developers and support personnel in debugging and diagnosing problems. This utility was made available as part of default builds beginning with MySQL Cluster NDB 6.1.3. It remains under development, and its syntax and behavior are subject to change in future releases. For this reason, it should be considered experimental at this time. The C++ source files for *Note `ndbd_redo_log_reader': mysql-cluster-programs-ndbd-redo-log-reader. can be found in the directory `/storage/ndb/src/kernel/blocks/dblqh/redoLogReader'. The following table includes options that are specific to the MySQL Cluster program *Note `ndbd_redo_log_reader': mysql-cluster-programs-ndbd-redo-log-reader. Additional descriptions follow the table. For options common to all MySQL Cluster programs, see *Note mysql-cluster-program-options-common::. *`ndbd_redo_log_reader' Command Line Options* Format Description IntroductionDeprecatedRemoved -nocheck Do not check records for errors -noprint Do not print records * Usage * ndbd_redo_log_reader FILE_NAME [OPTIONS] FILE_NAME is the name of a cluster redo log file. redo log files are located in the numbered directories under the data node's data directory (`DataDir'); the path under this directory to the redo log files matches the pattern `ndb_#_fs/D#/LCP/#/T#F#.Data'. In each case, the # represents a number (not necessarily the same number). For more information, see Cluster Data Node `FileSystemDir' Files (http://dev.mysql.com/doc/ndbapi/en/ndb-internals-ndbd-filesystemdir-files.html). The name of the file to be read may be followed by one or more of the options listed here: * Options for noprint *Command-Line `-noprint' Format* *Permitted Values * *Type* `boolean' *Default* `FALSE' `-noprint': Do not print the contents of the log file. * Options for nocheck *Command-Line `-nocheck' Format* *Permitted Values * *Type* `boolean' *Default* `FALSE' `-nocheck': Do not check the log file for errors. Like *Note `ndb_print_backup_file': mysql-cluster-programs-ndb-print-backup-file. and *Note `ndb_print_schema_file': mysql-cluster-programs-ndb-print-schema-file. (and unlike most of the *Note `NDB': mysql-cluster. utilities that are intended to be run on a management server host or to connect to a management server) *Note `ndbd_redo_log_reader': mysql-cluster-programs-ndbd-redo-log-reader. must be run on a cluster data node, since it accesses the data node file system directly. Because it does not make use of the management server, this utility can be used when the management server is not running, and even when the cluster has been completely shut down.  File: manual.info, Node: mysql-cluster-programs-ndb-restore, Next: mysql-cluster-programs-ndb-select-all, Prev: mysql-cluster-programs-ndbd-redo-log-reader, Up: mysql-cluster-programs 17.4.17 `ndb_restore' -- Restore a MySQL Cluster Backup ------------------------------------------------------- The cluster restoration program is implemented as a separate command-line utility *Note `ndb_restore': mysql-cluster-programs-ndb-restore, which can normally be found in the MySQL `bin' directory. This program reads the files created as a result of the backup and inserts the stored information into the database. *Note `ndb_restore': mysql-cluster-programs-ndb-restore. must be executed once for each of the backup files that were created by the `START BACKUP' command used to create the backup (see *Note mysql-cluster-backup-using-management-client::). This is equal to the number of data nodes in the cluster at the time that the backup was created. *Note*: Before using *Note `ndb_restore': mysql-cluster-programs-ndb-restore, it is recommended that the cluster be running in single user mode, unless you are restoring multiple data nodes in parallel. See *Note mysql-cluster-single-user-mode::, for more information. The following table includes options that are specific to the MySQL Cluster native backup restoration program *Note `ndb_restore': mysql-cluster-programs-ndb-restore. Additional descriptions follow the table. For options common to all MySQL Cluster programs, see *Note mysql-cluster-program-options-common::. *`ndb_restore' Command Line Options* Format Description IntroductionDeprecatedRemoved -append Append data to a tab-delimited file 5.1.18 -backup_path=pathPath to backup files directory 5.1.15-ndb-6.1.5, 5.1.17 -backupid=# Restore from the backup with the given ID -connect Same as connectstring -restore_data Restore table data and logs into NDB Cluster using the NDB API -disable-indexesCauses indexes from a backup to be 5.1.41-ndb-6.3.31, ignored; may decrease time needed 5.1.41-ndb-7.0.11, to restore data. 5.1.41-ndb-7.1.2 -dont_ignore_systab_0Do not ignore system table during restore. Experimental only; not for production use -exclude-databases=db-listList of one or more databases to 5.1.31-ndb-6.3.22, exclude (includes those not named) 5.1.32-ndb-6.4.3 -exclude-missing-columnsCauses columns from the backup 5.1.35-ndb-6.3.26, version of a table that are missing 5.1.35-ndb-7.0.7 from the version of the table in the database to be ignored. -exclude-tables=table-listList of one or more tables to 5.1.31-ndb-6.3.22, exclude (includes those in same 5.1.32-ndb-6.4.3 database that are not not named); each table reference must include the database name -fields-enclosed-by=charFields are enclosed with the 5.1.18 indicated character -fields-optionally-enclosed-byFields are optionally enclosed with 5.1.18 the indicated character -fields-terminated-by=charFields are terminated by the 5.1.18 indicated character -hex Print binary types in hexadecimal 5.1.18 format -include-databases=db-listList of one or more databases to 5.1.31-ndb-6.3.22, restore (excludes those not named) 5.1.32-ndb-6.4.3 -include-tables=table-listList of one or more tables to 5.1.31-ndb-6.3.22, restore (excludes those in same 5.1.32-ndb-6.4.3 database that are not named); each table reference must include the database name -lines-terminated-by=charLines are terminated by the 5.1.18 indicated character -lossy-conversionsAllow lossy conversions of column 5.1.51-ndb-7.1.11 values (type demotions or changes in sign) when restoring data from backup -restore_meta Restore metadata to NDB Cluster using the NDB API -ndb-nodegroup-map=mapNodegroup map for NDBCLUSTER storage engine. Syntax: list of (source_nodegroup, destination_nodegroup) -no-binlog If a mysqld is connected and using 5.1.24-ndb-6.2.16, binary logging, do not log the 5.1.24-ndb-6.3.16 restored data -no-restore-disk-objectsDo not restore Disk Data objects such as tablespaces and log file groups -no-upgrade Do not upgrade array type for 5.1.19 varsize attributes which do not already resize VAR data, and do not change column attributes -nodeid=# Back up files from node with this ID -parallelism=# Number of parallel transactions during restoration of data -preserve-trailing-spacesAllow preservation of tailing 5.1.23-ndb-6.3.8 spaces (including padding) when CHAR is promoted to VARCHAR or BINARY is promoted to VARBINARY -print Print metadata, data and log to stdout (equivalent to -print_meta -print_data -print_log) -print_data Print data to stdout -print_log Print to stdout -print_metadataPrint metadata to stdout -progress-frequency=#Print status of restoration each given number of seconds -promote-attributesAllow attributes to be promoted 5.1.23-ndb-6.3.8 when restoring data from backup -rebuild-indexesCauses multi-threaded ordered index 5.1.41-ndb-6.3.31, rebuilding of indexes found in the 5.1.41-ndb-7.0.11, backup. 5.1.41-ndb-7.1.2 -restore_epoch Restore epoch info into the status table. Convenient on a MySQL Cluster replication slave for starting replication. The row in mysql.ndb_apply_status with id 0 will be updated/inserted. -rewrite-database=old_dbname,new_dbnameRestores to a database with a 5.1.51-ndb-6.3.41, different name than the original 5.1.51-ndb-7.0.22, 5.1.51-ndb-7.1.11 -skip-broken-objectsCauses missing blob tables in the 5.1.51-ndb-6.3.40, backup file to be ignored. 5.1.51-ndb-7.0.21, 5.1.51-ndb-7.1.10 -skip-table-checkSkip table structure check during 5.1.17 restoring of data -skip-unknown-objectsCauses schema objects not 5.1.41-ndb-6.3.34, recognized by ndb_restore to be 5.1.41-ndb-7.0.15, ignored when restoring a backup 5.1.41-ndb-7.1.4 made from a newer MySQL Cluster version to an older version. -tab=path Creates a tab-separated .txt file 5.1.18 for each table in the given path -verbose=# Control level of verbosity in output Typical options for this utility are shown here: ndb_restore [-c CONNECTSTRING] -n NODE_ID [-m] -b BACKUP_ID \ -r --backup_path=/PATH/TO/BACKUP/FILES The `-c' option is used to specify a connectstring which tells `ndb_restore' where to locate the cluster management server. (See *Note mysql-cluster-connectstring::, for information on connectstrings.) If this option is not used, then *Note `ndb_restore': mysql-cluster-programs-ndb-restore. attempts to connect to a management server on `localhost:1186'. This utility acts as a cluster API node, and so requires a free connection `slot' to connect to the cluster management server. This means that there must be at least one `[api]' or `[mysqld]' section that can be used by it in the cluster `config.ini' file. It is a good idea to keep at least one empty `[api]' or `[mysqld]' section in `config.ini' that is not being used for a MySQL server or other application for this reason (see *Note mysql-cluster-api-definition::). You can verify that *Note `ndb_restore': mysql-cluster-programs-ndb-restore. is connected to the cluster by using the `SHOW' command in the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. management client. You can also accomplish this from a system shell, as shown here: shell> ndb_mgm -e "SHOW" `-n' is used to specify the node ID of the data node on which the backups were taken. The first time you run the *Note `ndb_restore': mysql-cluster-programs-ndb-restore. restoration program, you also need to restore the metadata. In other words, you must re-create the database tables--this can be done by running it with the `-m' option. Note that the cluster should have an empty database when starting to restore a backup. (In other words, you should start *Note `ndbd': mysql-cluster-programs-ndbd. with `--initial' prior to performing the restore. You should also remove manually any Disk Data files present in the data node's `DataDir'.) It is possible to restore data without restoring table metadata. Prior to MySQL 5.1.17, *Note `ndb_restore': mysql-cluster-programs-ndb-restore. did not perform any checks of table schemas; if a table was altered between the time the backup was taken and when *Note `ndb_restore': mysql-cluster-programs-ndb-restore. was run, *Note `ndb_restore': mysql-cluster-programs-ndb-restore. would still attempt to restore the data to the altered table. Beginning with MySQL 5.1.17, the default behavior is for *Note `ndb_restore': mysql-cluster-programs-ndb-restore. to fail with an error if table data do not match the table schema; this can be overridden using the `--skip-table-check' or `-s' option. Prior to MySQL 5.1.21, if this option is used, then *Note `ndb_restore': mysql-cluster-programs-ndb-restore. attempts to fit data into the existing table schema, but the result of restoring a backup to a table schema that does not match the original is unspecified. Beginning with MySQL Cluster NDB 6.3.35, MySQL Cluster NDB 7.0.16, and MySQL Cluster NDB 7.1.5, some of the restrictions on mismatches in column definitions when restoring data using *Note `ndb_restore': mysql-cluster-programs-ndb-restore. are relaxed; when one of these types of mismatches is encountered, *Note `ndb_restore': mysql-cluster-programs-ndb-restore. does not stop with an error as it did previously, but rather accepts the data and inserts it into the target table while issuing a warning to the user that this is being done. This behavior occurs whether or not either of the options `--skip-table-check' or `--promote-attributes' is in use. These differences in column definitions are of the following types: * Different `COLUMN_FORMAT' settings (`FIXED', `DYNAMIC', `DEFAULT') * Different `STORAGE' settings (`MEMORY', `DISK') * Different default values * Different distribution key settings Beginning with MySQL Cluster NDB 6.3.8, *Note `ndb_restore': mysql-cluster-programs-ndb-restore. supports limited _attribute promotion_ in much the same way that it is supported by MySQL replication; that is, data backed up from a column of a given type can generally be restored to a column using a `larger, similar' type. For example, data from a `CHAR(20)' column can be restored to a column declared as `VARCHAR(20)', `VARCHAR(30)', or `CHAR(30)'; data from a *Note `MEDIUMINT': numeric-types. column can be restored to a column of type *Note `INT': numeric-types. or *Note `BIGINT': numeric-types. See *Note replication-features-different-data-types::, for a table of type conversions currently supported by attribute promotion. Attribute promotion by *Note `ndb_restore': mysql-cluster-programs-ndb-restore. must be enabled explicitly, as follows: 1. Prepare the table to which the backup is to be restored. *Note `ndb_restore': mysql-cluster-programs-ndb-restore. cannot be used to re-create the table with a different definition from the original; this means that you must either create the table manually, or alter the columns which you wish to promote using *Note `ALTER TABLE': alter-table. after restoring the table metadata but before restoring the data. 2. Invoke *Note `ndb_restore': mysql-cluster-programs-ndb-restore. with the `--promote-attributes' option (short form `-A') when restoring the table data. Attribute promotion does not occur if this option is not used; instead, the restore operation fails with an error. `--lossy-conversions', `-L' Options for lossy-conversions *Version Introduced* 5.1.51-ndb-7.1.11 *Command-Line Format* `--lossy-conversions' ** `-L' *Permitted Values * *Type* `boolean' *Default* `FALSE' This option is intended to complement the `--promote-attributes' option. Using `--lossy-conversions' allows lossy conversions of column values (type demotions or changes in sign) when restoring data from backup. With some exceptions, the rules governing demotion are the same as for MySQL replication; see *Note replication-features-different-data-types::, for information about specific type conversions currently supported by attribute demotion. *Note `ndb_restore': mysql-cluster-programs-ndb-restore. reports any truncation of data that it performs during lossy conversions once per attribute and column. This option was added in MySQL Cluster NDB 7.1.11. The `--preserve-trailing-spaces' option is also available beginning with MySQL Cluster NDB 6.3.8. This option (short form `-R') causes trailing spaces to be preserved when promoting a *Note `CHAR': char. column to *Note `VARCHAR': char. or a `BINARY' column to *Note `VARBINARY': binary-varbinary. Otherwise, any trailing spaces are dropped from column values when they are inserted into the new columns. *Note*: Although you can promote *Note `CHAR': char. columns to *Note `VARCHAR': char. and `BINARY' columns to *Note `VARBINARY': binary-varbinary, you cannot promote *Note `VARCHAR': char. columns to *Note `CHAR': char. or *Note `VARBINARY': binary-varbinary. columns to `BINARY'. The `-b' option is used to specify the ID or sequence number of the backup, and is the same number shown by the management client in the `Backup BACKUP_ID completed' message displayed upon completion of a backup. (See *Note mysql-cluster-backup-using-management-client::.) *Important*: When restoring cluster backups, you must be sure to restore all data nodes from backups having the same backup ID. Using files from different backups will at best result in restoring the cluster to an inconsistent state, and may fail altogether. `--epoch' (short form: `-e') adds (or restores) epoch information to the cluster replication status table. This is useful for starting replication on a MySQL Cluster replication slave. When this option is used, the row in the `mysql.ndb_apply_status' having `0' in the `id' column is updated if it already exists; such a row is inserted if it does not already exist. (See *Note mysql-cluster-replication-backups::.) The path to the backup directory is required; this is supplied to *Note `ndb_restore': mysql-cluster-programs-ndb-restore. using the `--backup_path' option, and must include the subdirectory corresponding to the ID backup of the backup to be restored. For example, if the data node's `DataDir' is `/var/lib/mysql-cluster', then the backup directory is `/var/lib/mysql-cluster/BACKUP', and the backup files for the backup with the ID 3 can be found in `/var/lib/mysql-cluster/BACKUP/BACKUP-3'. The path may be absolute or relative to the directory in which the *Note `ndb_restore': mysql-cluster-programs-ndb-restore. executable is located, and may be optionally prefixed with `backup_path='. *Note*: Previous to MySQL 5.1.17 and MySQL Cluster NDB 6.1.5, the path to the backup directory was specified as shown here, with `backup_path=' being optional: [backup_path=]/PATH/TO/BACKUP/FILES Beginning with MySQL 5.1.17 and MySQL Cluster NDB 6.1.5, this syntax changed to `--backup_path=/PATH/TO/BACKUP/FILES', to conform more closely with options used by other MySQL programs; `--backupid' is required, and there is no short form for this option. It is possible to restore a backup to a database with a different configuration than it was created from. For example, suppose that a backup with backup ID `12', created in a cluster with two database nodes having the node IDs `2' and `3', is to be restored to a cluster with four nodes. Then *Note `ndb_restore': mysql-cluster-programs-ndb-restore. must be run twice--once for each database node in the cluster where the backup was taken. However, *Note `ndb_restore': mysql-cluster-programs-ndb-restore. cannot always restore backups made from a cluster running one version of MySQL to a cluster running a different MySQL version. See *Note mysql-cluster-upgrade-downgrade::, for more information. *Important*: It is not possible to restore a backup made from a newer version of MySQL Cluster using an older version of *Note `ndb_restore': mysql-cluster-programs-ndb-restore. You can restore a backup made from a newer version of MySQL to an older cluster, but you must use a copy of *Note `ndb_restore': mysql-cluster-programs-ndb-restore. from the newer MySQL Cluster version to do so. For example, to restore a cluster backup taken from a cluster running MySQL Cluster NDB 7.1.8 to a cluster running MySQL Cluster NDB 7.0.16, you must use the *Note `ndb_restore': mysql-cluster-programs-ndb-restore. that comes with the MySQL Cluster NDB 7.1.8 distribution. For more rapid restoration, the data may be restored in parallel, provided that there is a sufficient number of cluster connections available. That is, when restoring to multiple nodes in parallel, you must have an `[api]' or `[mysqld]' section in the cluster `config.ini' file available for each concurrent *Note `ndb_restore': mysql-cluster-programs-ndb-restore. process. However, the data files must always be applied before the logs. Formerly, when using *Note `ndb_restore': mysql-cluster-programs-ndb-restore. to restore a backup made from a MySQL 5.0 cluster to a 5.1 cluster, *Note `VARCHAR': char. columns were not resized and were recreated using the 5.0 fixed format. Beginning with MySQL 5.1.19, `ndb_restore' recreates such *Note `VARCHAR': char. columns using MySQL Cluster 5.1's variable-width format. Also beginning with MySQL 5.1.19, this behavior can be overridden using the `--no-upgrade' option (short form: `-u') when running *Note `ndb_restore': mysql-cluster-programs-ndb-restore. The `--print_data' option causes *Note `ndb_restore': mysql-cluster-programs-ndb-restore. to direct its output to `stdout'. *Note `TEXT': blob. and *Note `BLOB': blob. column values are always truncated to the first 256 bytes in the output; this cannot currrently be overridden when using `--print_data'. Beginning with MySQL 5.1.18, several additional options are available for use with the `--print_data' option in generating data dumps, either to `stdout', or to a file. These are similar to some of the options used with *Note `mysqldump': mysqldump, and are shown in the following list: * `--tab', `-T' Options for tab *Version Introduced* 5.1.18 *Command-Line `--tab=path' Format* ** `-T' This option causes `--print_data' to create dump files, one per table, each named `TBL_NAME.txt'. It requires as its argument the path to the directory where the files should be saved; use `.' for the current directory. * `--fields-enclosed-by=STRING' Options for fields-enclosed-by *Version Introduced* 5.1.18 *Command-Line `--fields-enclosed-by=char' Format* *Permitted Values * *Type* `string' *Default* `' Each column values are enclosed by the string passed to this option (regardless of data type; see next item). * `--fields-optionally-enclosed-by=STRING' Options for fields-optionally-enclosed-by *Version Introduced* 5.1.18 *Command-Line `--fields-optionally-enclosed-by' Format* *Permitted Values * *Type* `string' *Default* `' The string passed to this option is used to enclose column values containing character data (such as *Note `CHAR': char, *Note `VARCHAR': char, *Note `BINARY': binary-varbinary, *Note `TEXT': blob, or *Note `ENUM': enum.). * `--fields-terminated-by=STRING' Options for fields-terminated-by *Version Introduced* 5.1.18 *Command-Line `--fields-terminated-by=char' Format* *Permitted Values * *Type* `string' *Default* `\t (tab)' The string passed to this option is used to separate column values. The default value is a tab character (`\t'). * `--hex' Options for hex *Version Introduced* 5.1.18 *Command-Line `--hex' Format* If this option is used, all binary values are output in hexadecimal format. * `--fields-terminated-by=STRING' Options for fields-terminated-by *Version Introduced* 5.1.18 *Command-Line `--fields-terminated-by=char' Format* *Permitted Values * *Type* `string' *Default* `\t (tab)' This option specifies the string used to end each line of output. The default is a linefeed character (`\n'). * `--append' Options for append *Version Introduced* 5.1.18 *Command-Line `--append' Format* When used with the `--tab' and `--print_data' options, this causes the data to be appended to any existing files having the same names. *Note*: If a table has no explicit primary key, then the output generated when using the `--print_data' option includes the table's hidden primary key. Beginning with MySQL 5.1.18, it is possible to restore selected databases, or to restore selected tables from a given database using the syntax shown here: ndb_restore OTHER_OPTIONS DB_NAME,[DB_NAME[,...] | TBL_NAME[,TBL_NAME][,...]] In other words, you can specify either of the following to be restored: * All tables from one or more databases * One or more tables from a single database `--include-databases=DB_NAME[,DB_NAME][,...]' Options for include-databases *Version Introduced* 5.1.31-ndb-6.3.22, 5.1.32-ndb-6.4.3 *Command-Line Format* `--include-databases=db-list' *Permitted Values * *Type* `string' *Default* `' `--include-tables=DB_NAME.TBL_NAME[,DB_NAME.TBL_NAME][,...]' Options for include-tables *Version Introduced* 5.1.31-ndb-6.3.22, 5.1.32-ndb-6.4.3 *Command-Line Format* `--include-tables=table-list' *Permitted Values * *Type* `string' *Default* `' Beginning with MySQL Cluster NDB 6.3.22 and MySQL Cluster NDB 6.4.3, you can (and should) use instead the `--include-databases' option or the `--include-tables' option for restoring only specific databases or tables, respectively. `--include-databases' takes a comma-delimited list of databases to be restored. `--include-tables' takes a comma-delimited list of tables (in `DATABASE.TABLE' format) to be restored. When `--include-databases' or `--include-tables' is used, only those databases or tables named by the option are restored; all other databases and tables are excluded by *Note `ndb_restore': mysql-cluster-programs-ndb-restore, and are not restored. The following table shows several invocations of *Note `ndb_restore': mysql-cluster-programs-ndb-restore. using `--include-*' options (other options possibly required have been omitted for clarity), and the effects these have on restoring from a MySQL Cluster backup: Option Used Result `--include-databases=db1' Only tables in database `db1' are restored; all tables in all other databases are ignored `--include-databases=db1,db2' (or Only tables in databases `db1' and `--include-databases=db1' `db2' are restored; all tables in `--include-databases=db2') all other databases are ignored `--include-tables=db1.t1' Only table `t1' in database `db1' is restored; no other tables in `db1' or in any other database are restored `--include-tables=db1.t2,db2.t1' (or Only the table `t2' in database `--include-tables=db1.t2' `db1' and the table `t1' in database `--include-tables=db2.t1') `db2' are restored; no other tables in `db1', `db2', or any other database are restored Beginning with MySQL Cluster NDB 6.3.29 and MySQL Cluster NDB 7.0.10, you can use these two options together. For example, the following causes all tables in databases `db1' and `db2', together with the tables `t1' and `t2' in database `db3', to be restored (and no other databases or tables): shell> ndb_restore [...] --include-databases=db1,db2 --include-tables=db3.t1,db3.t2 (Again we have omitted other, possibly required, options in the example just shown.) *Note*: Prior to MySQL Cluster NDB 6.3.29 and MySQL Cluster NDB 7.0.10, multiple `--include-*' options were not handled correctly, and the result of the options shown in the previous example was that only the tables `db3.t1' and `db3.t2' were actually restored. (Bug#48907) `--exclude-databases=DB_NAME[,DB_NAME][,...]' Options for exclude-databases *Version Introduced* 5.1.31-ndb-6.3.22, 5.1.32-ndb-6.4.3 *Command-Line Format* `--exclude-databases=db-list' *Permitted Values * *Type* `string' *Default* `' `--exclude-tables=DB_NAME.TBL_NAME[,DB_NAME.TBL_NAME][,...]' Options for exclude-tables *Version Introduced* 5.1.31-ndb-6.3.22, 5.1.32-ndb-6.4.3 *Command-Line Format* `--exclude-tables=table-list' *Permitted Values * *Type* `string' *Default* `' Beginning with MySQL Cluster NDB 6.3.22 and MySQL Cluster NDB 6.4.3, it is possible to prevent one or more databases or tables from being restored using the *Note `ndb_restore': mysql-cluster-programs-ndb-restore. options `--exclude-databases' and `--exclude-tables'. `--exclude-databases' takes a comma-delimited list of one or more databases which should not be restored. `--exclude-tables' takes a comma-delimited list of one or more tables (using `DATABASE.TABLE' format) which should not be restored. When `--exclude-databases' or `--exclude-tables' is used, only those databases or tables named by the option are excluded; all other databases and tables are restored by *Note `ndb_restore': mysql-cluster-programs-ndb-restore. This table shows several invocations of *Note `ndb_restore': mysql-cluster-programs-ndb-restore. usng `--exclude-*' options (other options possibly required have been omitted for clarity), and the effects these options have on restoring from a MySQL Cluster backup: Option Used Result `--exclude-databases=db1' All tables in all databases except `db1' are restored; no tables in `db1' are restored `--exclude-databases=db1,db2' (or All tables in all databases except `--exclude-databases=db1' `db1' and `db2' are restored; no `--exclude-databases=db2') tables in `db1' or `db2' are restored `--exclude-tables=db1.t1' All tables except `t1' in database `db1' are restored; all other tables in `db1' are restored; all tables in all other databases are restored `--exclude-tables=db1.t2,db2.t1' (or All tables in database `db1' except `--exclude-tables=db1.t2' for `t2' and all tables in database `--exclude-tables=db2.t1)' `db2' except for table `t1' are restored; no other tables in `db1' or `db2' are restored; all tables in all other databases are restored Beginning with MySQL Cluster NDB 6.3.29 and MySQL Cluster NDB 7.0.10, you can use these two options together. For example, the following causes all tables in all databases _except for_ databases `db1' and `db2', along with the tables `t1' and `t2' in database `db3', _not_ to be restored: shell> ndb_restore [...] --exclude-databases=db1,db2 --exclude-tables=db3.t1,db3.t2 (Again, we have omitted other possibly necessary options in the interest of clarity and brevity from the example just shown.) *Note*: Prior to MySQL Cluster NDB 6.3.29 and MySQL Cluster NDB 7.0.10, multiple `--exclude-*' options were not handled correctly, with the result that the options shown in the previous example caused ndb_restore to exclude only the tables `db3.t1' and `db3.t2'. (Bug#48907) Beginning with MySQL Cluster NDB 6.3.29 and MySQL Cluster NDB 7.0.10, you can use `--include-*' and `--exclude-*' options together, subject to the following rules: * The actions of all `--include-*' and `--exclude-*' options are cumulative. * All `--include-*' and `--exclude-*' options are evaluated in the order passed to ndb_restore, from right to left. * In the event of conflicting options, the first (rightmost) option takes precedence. In other words, the first option (going from right to left) that matches against a given database or table `wins'. For example, the following set of options causes *Note `ndb_restore': mysql-cluster-programs-ndb-restore. to restore all tables from database `db1' except `db1.t1', while restoring no other tables from any other databases: --include-databases=db1 --exclude-tables=db1.t1 However, reversing the order of the options just given simply causes all tables from database `db1' to be restored (including `db1.t1', but no tables from any other database), because the `--include-databases' option, being farthest to the right, is the first match against database `db1' and thus takes precedence over any other option that matches `db1' or any tables in `db1': --exclude-tables=db1.t1 --include-databases=db1 *Note*: Prior to MySQL Cluster NDB 6.3.29 and MySQL Cluster NDB 7.0.10, it was not possible to use `--include-databases' or `--include-tables' together with `--exclude-databases' or `--exclude-tables', as these combinations were evaluated inconsistently. (Bug#48907) `--exclude-missing-columns' Options for exclude-missing-columns *Version Introduced* 5.1.35-ndb-6.3.26, 5.1.35-ndb-7.0.7 *Command-Line Format* `--exclude-missing-columns' Beginning with MySQL Cluster NDB 6.3.26 and MySQL Cluster NDB 7.0.7, it is also possible to restore only selected table columns using the `--exclude-missing-columns' option. When this option is used, *Note `ndb_restore': mysql-cluster-programs-ndb-restore. ignores any columns missing from tables being restored as compared to the versions of those tables found in the backup. This option applies to all tables being restored. If you wish to apply this option only to selected tables or databases, you can use it in combination with one or more of the options described in the previous paragraph to do so, then restore data to the remaining tables using a complementary set of these options. `--disable-indexes' Options for disable-indexes *Version Introduced* 5.1.41-ndb-6.3.31, 5.1.41-ndb-7.0.11, 5.1.41-ndb-7.1.2 *Command-Line Format* `--disable-indexes' Beginning with MySQL Cluster NDB 6.3.31, MySQL Cluster NDB 7.0.11, and MySQL CLuster NDB 7.1.2, you can use this option with *Note `ndb_restore': mysql-cluster-programs-ndb-restore. to disable restoration of indexes during restoration of the data from a native NDB backup. Afterwards, you can restore indexes for all tables at once with multi-threaded building of indexes using `--rebuild-indexes', which should be faster than rebuilding indexes concurrently for very large tables. `--rebuild-indexes' Options for rebuild-indexes *Version Introduced* 5.1.41-ndb-6.3.31, 5.1.41-ndb-7.0.11, 5.1.41-ndb-7.1.2 *Command-Line Format* `--rebuild-indexes' Beginning with MySQL Cluster NDB 6.3.31, MySQL Cluster NDB 7.0.11, and MySQL CLuster NDB 7.1.2, you can use this option with *Note `ndb_restore': mysql-cluster-programs-ndb-restore. to cause multi-threaded rebuilding of the ordered indexes while restoring a native `NDB' backup. `--skip-broken-objects' Options for skip-broken-objects *Version Introduced* 5.1.51-ndb-6.3.40, 5.1.51-ndb-7.0.21, 5.1.51-ndb-7.1.10 *Command-Line Format* `--skip-broken-objects' This option causes *Note `ndb_restore': mysql-cluster-programs-ndb-restore. to ignore corrupt tables while reading a native *Note `NDB': mysql-cluster. backup, and to continue restoring any remaining tables (that are not also corrupted). Currently, the `--skip-broken-objects' option works only in the case of missing blob parts tables. This option was added in MySQL Cluster NDB 6.3.40, MySQL Cluster NDB 7.0.21, and MySQL CLuster NDB 7.1.10. `--skip-unknown-objects' Options for skip-unknown-objects *Version Introduced* 5.1.41-ndb-6.3.34, 5.1.41-ndb-7.0.15, 5.1.41-ndb-7.1.4 *Command-Line Format* `--skip-unknown-objects' This option causes *Note `ndb_restore': mysql-cluster-programs-ndb-restore. to ignore any schema objects it does not recgnize while reading a native *Note `NDB': mysql-cluster. backup. This can be used for restoring a backup made from a cluster running MySQL Cluster NDB 7.0 to a cluster running MySQL Cluster NDB 6.3. This option was added in MySQL Cluster NDB 6.3.34, MySQL Cluster NDB 7.0.15, and MySQL CLuster NDB 7.1.4. `--rewrite-database=OLD_DBNAME,NEW_DBNAME' Options for rewrite-database *Version Introduced* 5.1.51-ndb-6.3.41, 5.1.51-ndb-7.0.22, 5.1.51-ndb-7.1.11 *Command-Line Format* `--rewrite-database=old_dbname,new_dbname' *Permitted Values * *Type* `string' *Default* `' This option makes it possible to restore to a database having a different name from that used in the backup. For example, if a backup is made of a database named `products', you can restore the data it contains to a database named `inventory', use this option as shown here (omitting any other options that might be required): shell> ndb_restore --rewrite-database=product,inventory The option can be employed multiple times in a single invocation of *Note `ndb_restore': mysql-cluster-programs-ndb-restore. Thus it is possible to restore simultaneously from a database named `db1' to a database named `db2' and from a database named `db3' to one named `db4' using `--rewrite-database=db1,db2 --rewrite-database=db3,db4'. Other *Note `ndb_restore': mysql-cluster-programs-ndb-restore. options may be used between multiple occurrences of `--rewrite-database'. In the event of conflicts between multiple `--rewrite-database' options, the last `--rewrite-database' option used, reading from left to right, is the one that takes effect. For example, if `--rewrite-database=db1,db2 --rewrite-database=db1,db3' is used, only `--rewrite-database=db1,db3' is honored, and `--rewrite-database=db1,db2' is ignored. It is also possible to restore from multiple databases to a single database, so that `--rewrite-database=db1,db3 --rewrite-database=db2,db3' restores all tables and data from databases `db1' and `db2' into database `db3'. *Important*: When restoring from multiple backup databases into a single target database using `--rewrite-database', no check is made for collisions between table or other object names, and the order in which rows are restored is not guaranteed. This means that it is possible in such cases for rows to be overwritten and updates to be lost. This option was added in MySQL Cluster NDB 6.3.41, MySQL Cluster NDB 7.0.22, and MySQL Cluster NDB 7.1.11. Error reporting *Note `ndb_restore': mysql-cluster-programs-ndb-restore. reports both temporary and permanent errors. In the case of temporary errors, it may able to recover from them. Beginning with MySQL 5.1.12, it reports `Restore successful, but encountered temporary error, please look at configuration' in such cases. *Important*: After using *Note `ndb_restore': mysql-cluster-programs-ndb-restore. to initialize a MySQL Cluster for use in circular replication, binary logs on the SQL node acting as the replication slave are not automatically created, and you must cause them to be created manually. To cause the binary logs to be created, issue a *Note `SHOW TABLES': show-tables. statement on that SQL node before running *Note `START SLAVE': start-slave. This is a known issue in MySQL Cluster.  File: manual.info, Node: mysql-cluster-programs-ndb-select-all, Next: mysql-cluster-programs-ndb-select-count, Prev: mysql-cluster-programs-ndb-restore, Up: mysql-cluster-programs 17.4.18 `ndb_select_all' -- Print Rows from an NDB Table -------------------------------------------------------- *Note `ndb_select_all': mysql-cluster-programs-ndb-select-all. prints all rows from an *Note `NDB': mysql-cluster. table to `stdout'. * Usage * ndb_select_all -c CONNECT_STRING TBL_NAME -d DB_NAME [> FILE_NAME] * Additional Options * * `--lock=LOCK_TYPE', `-l LOCK_TYPE' Employs a lock when reading the table. Possible values for LOCK_TYPE are: * `0': Read lock * `1': Read lock with hold * `2': Exclusive read lock There is no default value for this option. * `--order=INDEX_NAME', `-o INDEX_NAME' Orders the output according to the index named INDEX_NAME. Note that this is the name of an index, not of a column, and that the index must have been explicitly named when created. * `--descending', `-z' Sorts the output in descending order. This option can be used only in conjunction with the `-o' (`--order') option. * `--header=FALSE' Excludes column headers from the output. * `--useHexFormat' `-x' Causes all numeric values to be displayed in hexadecimal format. This does not affect the output of numerals contained in strings or datetime values. * `--delimiter=CHARACTER', `-D CHARACTER' Causes the CHARACTER to be used as a column delimiter. Only table data columns are separated by this delimiter. The default delimiter is the tab character. * `--disk' Adds a disk reference column to the output. The column is nonempty only for Disk Data tables having nonindexed columns. * `--rowid' Adds a `ROWID' column providing information about the fragments in which rows are stored. * `--gci' Adds a column to the output showing the global checkpoint at which each row was last updated. See *Note mysql-cluster-overview::, and *Note mysql-cluster-log-events::, for more information about checkpoints. * `--tupscan', `-t' Scan the table in the order of the tuples. * `--nodata' Causes any table data to be omitted. * Sample Output * Output from a MySQL *Note `SELECT': select. statement: mysql> SELECT * FROM ctest1.fish; +----+-----------+ | id | name | +----+-----------+ | 3 | shark | | 6 | puffer | | 2 | tuna | | 4 | manta ray | | 5 | grouper | | 1 | guppy | +----+-----------+ 6 rows in set (0.04 sec) Output from the equivalent invocation of *Note `ndb_select_all': mysql-cluster-programs-ndb-select-all.: shell> ./ndb_select_all -c localhost fish -d ctest1 id name 3 [shark] 6 [puffer] 2 [tuna] 4 [manta ray] 5 [grouper] 1 [guppy] 6 rows returned NDBT_ProgramExit: 0 - OK Note that all string values are enclosed by square brackets (``['...`]'') in the output of *Note `ndb_select_all': mysql-cluster-programs-ndb-select-all. For a further example, consider the table created and populated as shown here: CREATE TABLE dogs ( id INT(11) NOT NULL AUTO_INCREMENT, name VARCHAR(25) NOT NULL, breed VARCHAR(50) NOT NULL, PRIMARY KEY pk (id), KEY ix (name) ) TABLESPACE ts STORAGE DISK ENGINE=NDBCLUSTER; INSERT INTO dogs VALUES ('', 'Lassie', 'collie'), ('', 'Scooby-Doo', 'Great Dane'), ('', 'Rin-Tin-Tin', 'Alsatian'), ('', 'Rosscoe', 'Mutt'); This demonstrates the use of several additional *Note `ndb_select_all': mysql-cluster-programs-ndb-select-all. options: shell> ./ndb_select_all -d ctest1 dogs -o ix -z --gci --disk GCI id name breed DISK_REF 834461 2 [Scooby-Doo] [Great Dane] [ m_file_no: 0 m_page: 98 m_page_idx: 0 ] 834878 4 [Rosscoe] [Mutt] [ m_file_no: 0 m_page: 98 m_page_idx: 16 ] 834463 3 [Rin-Tin-Tin] [Alsatian] [ m_file_no: 0 m_page: 34 m_page_idx: 0 ] 835657 1 [Lassie] [Collie] [ m_file_no: 0 m_page: 66 m_page_idx: 0 ] 4 rows returned NDBT_ProgramExit: 0 - OK *Note*: In earlier MySQL Cluster NDB 7.0 and 7.1 releases, *Note `ndb_select_all': mysql-cluster-programs-ndb-select-all. did not print any output for `NULL' values as it did in MySQL Cluster NDB 6.3 and earlier release series. This issue was fixed in MySQL Cluster NDB 7.0.22 and MySQL Cluster NDB 7.1.11. (Bug #60045)  File: manual.info, Node: mysql-cluster-programs-ndb-select-count, Next: mysql-cluster-programs-ndb-show-tables, Prev: mysql-cluster-programs-ndb-select-all, Up: mysql-cluster-programs 17.4.19 `ndb_select_count' -- Print Row Counts for NDB Tables ------------------------------------------------------------- *Note `ndb_select_count': mysql-cluster-programs-ndb-select-count. prints the number of rows in one or more *Note `NDB': mysql-cluster. tables. With a single table, the result is equivalent to that obtained by using the MySQL statement `SELECT COUNT(*) FROM TBL_NAME'. * Usage * ndb_select_count [-c CONNECT_STRING] -dDB_NAME TBL_NAME[, TBL_NAME2[, ...]] * Additional Options * None that are specific to this application. However, you can obtain row counts from multiple tables in the same database by listing the table names separated by spaces when invoking this command, as shown under *Sample Output*. * Sample Output * shell> ./ndb_select_count -c localhost -d ctest1 fish dogs 6 records in table fish 4 records in table dogs NDBT_ProgramExit: 0 - OK  File: manual.info, Node: mysql-cluster-programs-ndb-show-tables, Next: mysql-cluster-programs-ndb-size-pl, Prev: mysql-cluster-programs-ndb-select-count, Up: mysql-cluster-programs 17.4.20 `ndb_show_tables' -- Display List of NDB Tables ------------------------------------------------------- *Note `ndb_show_tables': mysql-cluster-programs-ndb-show-tables. displays a list of all *Note `NDB': mysql-cluster. database objects in the cluster. By default, this includes not only both user-created tables and *Note `NDB': mysql-cluster. system tables, but *Note `NDB': mysql-cluster.-specific indexes, internal triggers, and MySQL Cluster Disk Data objects as well. The following table includes options that are specific to the MySQL Cluster program *Note `ndb_show_tables': mysql-cluster-programs-ndb-show-tables. Additional descriptions follow the table. For options common to all MySQL Cluster programs, see *Note mysql-cluster-program-options-common::. *`ndb_show_tables' Command Line Options* Format Description IntroductionDeprecatedRemoved -database=stringSpecifies the database in which the table is found -loops=# Number of times to repeat output -parsable Return output suitable for MySQL LOAD DATA INFILE statement -show-temp-statusShow table temporary flag -type=# Limit output to objects of this type -unqualified Do not qualify table names * Usage * ndb_show_tables [-c CONNECT_STRING] * `--database', `-d' Specifies the name of the database in which the tables are found. * `--loops', `-l' Specifies the number of times the utility should execute. This is 1 when this option is not specified, but if you do use the option, you must supply an integer argument for it. * `--parsable', `-p' Using this option causes the output to be in a format suitable for use with *Note `LOAD DATA INFILE': load-data. * `--show-temp-status' If specified, this causes temporary tables to be displayed. * `--type', `-t' Can be used to restrict the output to one type of object, specified by an integer type code as shown here: * `1': System table * `2': User-created table * `3': Unique hash index Any other value causes all *Note `NDB': mysql-cluster. database objects to be listed (the default). * `--unqualified', `-u' If specified, this causes unqualified object names to be displayed. *Note*: Only user-created MySQL Cluster tables may be accessed from MySQL; system tables such as `SYSTAB_0' are not visible to *Note `mysqld': mysqld. However, you can examine the contents of system tables using *Note `NDB': mysql-cluster. API applications such as *Note `ndb_select_all': mysql-cluster-programs-ndb-select-all. (see *Note mysql-cluster-programs-ndb-select-all::).  File: manual.info, Node: mysql-cluster-programs-ndb-size-pl, Next: mysql-cluster-programs-ndb-waiter, Prev: mysql-cluster-programs-ndb-show-tables, Up: mysql-cluster-programs 17.4.21 `ndb_size.pl' -- NDBCLUSTER Size Requirement Estimator -------------------------------------------------------------- This is a Perl script that can be used to estimate the amount of space that would be required by a MySQL database if it were converted to use the *Note `NDBCLUSTER': mysql-cluster. storage engine. Unlike the other utilities discussed in this section, it does not require access to a MySQL Cluster (in fact, there is no reason for it to do so). However, it does need to access the MySQL server on which the database to be tested resides. * Requirements * * A running MySQL server. The server instance does not have to provide support for MySQL Cluster. * A working installation of Perl. * The `DBI' module, which can be obtained from CPAN if it is not already part of your Perl installation. (Many Linux and other operating system distributions provide their own packages for this library.) * Previous to MySQL 5.1.18, *Note `ndb_size.pl': mysql-cluster-programs-ndb-size-pl. also required the `HTML::Template' module and an associated template file `share/mysql/ndb_size.tmpl'. Beginning with MySQL 5.1.18, `ndb_size.tmpl' is no longer needed (or included). * A MySQL user account having the necessary privileges. If you do not wish to use an existing account, then creating one using `GRANT USAGE ON DB_NAME.*'--where DB_NAME is the name of the database to be examined--is sufficient for this purpose. `ndb_size.pl' can also be found in the MySQL sources in `storage/ndb/tools'. If this file is not present in your MySQL installation, you can obtain it from the MySQL Forge project page (http://forge.mysql.com/projects/project.php?id=88). The following table includes options that are specific to the MySQL Cluster program *Note `ndb_size.pl': mysql-cluster-programs-ndb-size-pl. Additional descriptions follow the table. For options common to all MySQL Cluster programs, see *Note mysql-cluster-program-options-common::. *`ndb_size.pl' Command Line Options* Format Description IntroductionDeprecatedRemoved -database=dbnameThe databae or databases to examine; accepts a comma-delimited list; the default is ALL (use all databases found on the server) -excludedbs=db-listSkip any databases in a comma-separated list of databases -excludetables=tbl-listSkip any tables in a comma-separated list of tables -format=string Set output format (text or HTML) -hostname[:port]Specify host and optional port as host[:port] -loadqueries=fileLoads all queries from the file specified; does not connect to a database -password=stringSpecify a MySQL user password -real_table_name=tableDesignates a table to handle unique 5.1.22-ndb-6.2.5 index size calculations -savequeries=fileSaves all queries to the database into the file specified -socket=file Specify a socket to connect to 5.1.22-ndb-6.2.5 -user=string Specify a MySQL user name * Usage * perl ndb_size.pl DB_NAME|ALL] [--hostname=HOST[:PORT]] [--socket=SOCKET] [--user=USER] \ [--password=PASSWORD] [--help|-h] [--format=(html|text)] [--loadqueries=FILE_NAME] [--savequeries=FILE_NAME] By default, this utility attempts to analyze all databases on the server. You can specify a single database using the `--database' option; the default behavior can be made explicit by using `ALL' for the name of the database. You can also exclude one or more databases by using the `--excludedbs' with a comma-separated list of the names of the databases to be skipped. Similarly, you can cause specific tables to be skipped by listing their names, separated by commas, following the optional `--excludetables' option. A host name (and possibly a port as well) can be specified using `--hostname'; the default is `localhost:3306'. If necessary, you can also specify a socket; the default is `/var/lib/mysql.sock'. A MySQL user name and password can be specified the corresponding options shown. It also possible to control the format of the output using the `--format' option; this can take either of the values `html' or `text', with `text' being the default. An example of the text output is shown here: shell> ndb_size.pl --database=test --socket=/tmp/mysql.sock ndb_size.pl report for database: 'test' (1 tables) -------------------------------------------------- Connected to: DBI:mysql:host=localhost;mysql_socket=/tmp/mysql.sock Including information for versions: 4.1, 5.0, 5.1 test.t1 ------- DataMemory for Columns (* means varsized DataMemory): Column Name Type Varsized Key 4.1 5.0 5.1 HIDDEN_NDB_PKEY bigint PRI 8 8 8 c2 varchar(50) Y 52 52 4* c1 int(11) 4 4 4 -- -- -- Fixed Size Columns DM/Row 64 64 12 Varsize Columns DM/Row 0 0 4 DataMemory for Indexes: Index Name Type 4.1 5.0 5.1 PRIMARY BTREE 16 16 16 -- -- -- Total Index DM/Row 16 16 16 IndexMemory for Indexes: Index Name 4.1 5.0 5.1 PRIMARY 33 16 16 -- -- -- Indexes IM/Row 33 16 16 Summary (for THIS table): 4.1 5.0 5.1 Fixed Overhead DM/Row 12 12 16 NULL Bytes/Row 4 4 4 DataMemory/Row 96 96 48 (Includes overhead, bitmap and indexes) Varsize Overhead DM/Row 0 0 8 Varsize NULL Bytes/Row 0 0 4 Avg Varside DM/Row 0 0 16 No. Rows 0 0 0 Rows/32kb DM Page 340 340 680 Fixedsize DataMemory (KB) 0 0 0 Rows/32kb Varsize DM Page 0 0 2040 Varsize DataMemory (KB) 0 0 0 Rows/8kb IM Page 248 512 512 IndexMemory (KB) 0 0 0 Parameter Minimum Requirements ------------------------------ * indicates greater than default Parameter Default 4.1 5.0 5.1 DataMemory (KB) 81920 0 0 0 NoOfOrderedIndexes 128 1 1 1 NoOfTables 128 1 1 1 IndexMemory (KB) 18432 0 0 0 NoOfUniqueHashIndexes 64 0 0 0 NoOfAttributes 1000 3 3 3 NoOfTriggers 768 5 5 5 For debugging purposes, the Perl arrays containing the queries run by this script can be read from the file specified using can be saved to a file using `--savequeries'; a file containing such arrays to be read in during script execution can be specified using `--loadqueries'. Neither of these options has a default value. To produce output in HTML format, use the `--format' option and redirect the output to a file, as shown in this example: shell> ndb_size.pl --database=test --socket=/tmp/mysql.sock --format=html > ndb_size.html (Without the redirection, the output is sent to `stdout'.) This figure shows a portion of the generated `ndb_size.html' output file, as viewed in a Web browser: Partial sample output from *Note `ndb_size.pl': mysql-cluster-programs-ndb-size-pl. as viewed in a Web browser. The output from this script includes the following information: * Minimum values for the `DataMemory', `IndexMemory', `MaxNoOfTables', `MaxNoOfAttributes', `MaxNoOfOrderedIndexes', `MaxNoOfUniqueHashIndexes', and `MaxNoOfTriggers' configuration parameters required to accommodate the tables analyzed. * Memory requirements for all of the tables, attributes, ordered indexes, and unique hash indexes defined in the database. * The `IndexMemory' and `DataMemory' required per table and table row. *Note*: Prior to MySQL 5.1.23, MySQL Cluster NDB 6.2.5, and MySQL Cluster NDB 6.3.7, `ndb_size.pl' was invoked as shown here: perl ndb_size.pl DB_NAME HOSTNAME USERNAME PASSWORD > FILE_NAME.html For more information about this change, see Bug#28683 and Bug#28253.  File: manual.info, Node: mysql-cluster-programs-ndb-waiter, Next: mysql-cluster-program-options-common, Prev: mysql-cluster-programs-ndb-size-pl, Up: mysql-cluster-programs 17.4.22 `ndb_waiter' -- Wait for MySQL Cluster to Reach a Given Status ---------------------------------------------------------------------- *Note `ndb_waiter': mysql-cluster-programs-ndb-waiter. repeatedly (each 100 milliseconds) prints out the status of all cluster data nodes until either the cluster reaches a given status or the `--timeout' limit is exceeded, then exits. By default, it waits for the cluster to achieve `STARTED' status, in which all nodes have started and connected to the cluster. This can be overridden using the `--no-contact' and `--not-started' options (see Additional Options). The node states reported by this utility are as follows: * `NO_CONTACT': The node cannot be contacted. * `UNKNOWN': The node can be contacted, but its status is not yet known. Usually, this means that the node has received a `START' or `RESTART' command from the management server, but has not yet acted on it. * `NOT_STARTED': The node has stopped, but remains in contact with the cluster. This is seen when restarting the node using the management client's `RESTART' command. * `STARTING': The node's *Note `ndbd': mysql-cluster-programs-ndbd. process has started, but the node has not yet joined the cluster. * `STARTED': The node is operational, and has joined the cluster. * `SHUTTING_DOWN': The node is shutting down. * `SINGLE USER MODE': This is shown for all cluster data nodes when the cluster is in single user mode. * Usage * ndb_waiter [-c CONNECT_STRING] * Additional Options * * `--no-contact', `-n' Instead of waiting for the `STARTED' state, *Note `ndb_waiter': mysql-cluster-programs-ndb-waiter. continues running until the cluster reaches `NO_CONTACT' status before exiting. * `--not-started' Instead of waiting for the `STARTED' state, *Note `ndb_waiter': mysql-cluster-programs-ndb-waiter. continues running until the cluster reaches `NOT_STARTED' status before exiting. * `--timeout=SECONDS', `-t SECONDS' Time to wait. The program exits if the desired state is not achieved within this number of seconds. The default is 120 seconds (1200 reporting cycles). * `--single-user' The program waits for the cluster to enter single user mode. * `--nowait-nodes=LIST' When this option is used, ndb_waiter does not wait for the nodes whose IDs are listed. The list is comma-delimited; ranges can be indicated by dashes, as shown here: shell> ndb_waiter --nowait-nodes=1,3,7-9 *Important*: Do _not_ use this option together with the `--wait-nodes' option. This option was added in MySQL Cluster NDB 6.2.1. * `--wait-nodes=LIST', `-w LIST' When this option is used, *Note `ndb_waiter': mysql-cluster-programs-ndb-waiter. waits only for the nodes whose IDs are listed. The list is comma-delimited; ranges can be indicated by dashes, as shown here: shell> ndb_waiter --wait-nodes=2,4-6,10 *Important*: Do _not_ use this option together with the `--nowait-nodes' option. This option was added in MySQL Cluster NDB 6.3.34, 7.0.15, and 7.1.4. Sample Output Shown here is the output from *Note `ndb_waiter': mysql-cluster-programs-ndb-waiter. when run against a 4-node cluster in which two nodes have been shut down and then started again manually. Duplicate reports (indicated by ``...'') are omitted. shell> ./ndb_waiter -c localhost Connecting to mgmsrv at (localhost) State node 1 STARTED State node 2 NO_CONTACT State node 3 STARTED State node 4 NO_CONTACT Waiting for cluster enter state STARTED ... State node 1 STARTED State node 2 UNKNOWN State node 3 STARTED State node 4 NO_CONTACT Waiting for cluster enter state STARTED ... State node 1 STARTED State node 2 STARTING State node 3 STARTED State node 4 NO_CONTACT Waiting for cluster enter state STARTED ... State node 1 STARTED State node 2 STARTING State node 3 STARTED State node 4 UNKNOWN Waiting for cluster enter state STARTED ... State node 1 STARTED State node 2 STARTING State node 3 STARTED State node 4 STARTING Waiting for cluster enter state STARTED ... State node 1 STARTED State node 2 STARTED State node 3 STARTED State node 4 STARTING Waiting for cluster enter state STARTED ... State node 1 STARTED State node 2 STARTED State node 3 STARTED State node 4 STARTED Waiting for cluster enter state STARTED NDBT_ProgramExit: 0 - OK *Note*: If no connectstring is specified, then *Note `ndb_waiter': mysql-cluster-programs-ndb-waiter. tries to connect to a management on `localhost', and reports `Connecting to mgmsrv at (null)'.  File: manual.info, Node: mysql-cluster-program-options-common, Prev: mysql-cluster-programs-ndb-waiter, Up: mysql-cluster-programs 17.4.23 Options Common to MySQL Cluster Programs ------------------------------------------------ All MySQL Cluster programs (except for *Note `mysqld': mysqld.) take the options described in this section. Users of earlier MySQL Cluster versions should note that some of these options have been changed to make them consistent with one another as well as with *Note `mysqld': mysqld. You can use the `--help' option with any MySQL Cluster program to view a list of the options which it supports. The options in the following table are common to all MySQL Cluster executables. *Common MySQL Cluster Command Line Options* Format Description IntroductionDeprecatedRemoved -character-sets-dir=pathDirectory where character sets are -ndb-connectstring=nameSet connect string for connecting to ndb_mgmd. Syntax: [nodeid=;][host=][:]. Overrides specifying entries in NDB_CONNECTSTRING and my.cnf -core-file Write core on errors (defaults to TRUE in debug builds) -debug=options Enable output from debug calls. Can be used only for versions compiled with debugging enabled -help Display help message and exit -ndb-mgmd-host=nameSet host and port for connecting to ndb_mgmd. Syntax: [:]. Overrides specifying entries in NDB_CONNECTSTRING and my.cnf -ndb-nodeid=# Set node id for this node -ndb-optimized-node-selectionSelect nodes for transactions in a more optimal way -ndb-shm Allow optimizing using shared 5.1.47-ndb-7.1.5 memory connections when available (was EXPERIMENTAL; REMOVED in later versions) -V Output version information and exit For options specific to individual MySQL Cluster programs, see *Note mysql-cluster-programs::. See *Note mysql-cluster-program-options-mysqld::, for *Note `mysqld': mysqld. options relating to MySQL Cluster. * `--help' `--usage', `-?' Options for help *Command-Line `--help' Format* ** `--usage' ** `-?' Prints a short list with descriptions of the available command options. * `--character-sets-dir=NAME' Options for character-sets-dir *Command-Line `--character-sets-dir=path' Format* *Permitted Values * *Type* `file name' *Default* `' Tells the program where to find character set information. * `--connect-string=CONNECT_STRING', `-c CONNECT_STRING' Options for connectstring *Command-Line `--ndb-connectstring=name' Format* ** `--connect-string=name' ** `-c' *Permitted Values * *Type* `string' *Default* `localhost:1186' CONNECT_STRING sets the connectstring to the management server as a command option. shell> ndbd --connect-string="nodeid=2;host=ndb_mgmd.mysql.com:1186" For more information, see *Note mysql-cluster-connectstring::. * `--core-file' Options for core-file *Command-Line `--core-file' Format* *Permitted Values * *Type* `boolean' *Default* `FALSE' Write a core file if the program dies. The name and location of the core file are system-dependent. (For MySQL Cluster programs nodes running on Linux, the default location is the program's working directory--for a data node, this is the node's `DataDir'.) For some systems, there may be restrictions or limitations; for example, it might be necessary to execute `ulimit -c unlimited' before starting the server. Consult your system documentation for detailed information. If MySQL Cluster was built using the `--debug' option for `configure', then `--core-file' is enabled by default. For regular builds, `--core-file' is disabled by default. * `--debug[=OPTIONS]' Options for debug *Command-Line `--debug=options' Format* *Permitted Values * *Type* `string' *Default* `d:t:O,/tmp/ndb_restore.trace' This option can be used only for versions compiled with debugging enabled. It is used to enable output from debug calls in the same manner as for the *Note `mysqld': mysqld. process. * `--ndb-mgmd-host=HOST[:PORT]' Can be used to set the host and port number of the management server to connect to. * `--ndb-nodeid=#' Options for ndb-nodeid *Command-Line `--ndb-nodeid=#' Format* *Permitted Values * *Type* `numeric' *Default* `0' Sets this node's MySQL Cluster node ID. _The range of permitted values depends on the node's type (data, management, or API) and the MySQL Cluster software version_. See *Note mysql-cluster-limitations-limits::, for more information. * `--ndb-optimized-node-selection' Options for ndb-optimized-node-selection *Command-Line `--ndb-optimized-node-selection' Format* *Permitted Values * *Type* `boolean' *Default* `TRUE' Optimize selection of nodes for transactions. Enabled by default. * `--version', `-V' Options for version *Command-Line `-V' Format* ** `--version' Prints the MySQL Cluster version number of the executable. The version number is relevant because not all versions can be used together, and the MySQL Cluster startup process verifies that the versions of the binaries being used can co-exist in the same cluster. This is also important when performing an online (rolling) software upgrade or downgrade of MySQL Cluster. See *Note mysql-cluster-rolling-restart::), for more information.  File: manual.info, Node: mysql-cluster-management, Next: mysql-cluster-replication, Prev: mysql-cluster-programs, Up: mysql-cluster 17.5 Management of MySQL Cluster ================================ * Menu: * mysql-cluster-start-phases:: Summary of MySQL Cluster Start Phases * mysql-cluster-mgm-client-commands:: Commands in the MySQL Cluster Management Client * mysql-cluster-backup:: Online Backup of MySQL Cluster * mysql-cluster-rolling-restart:: Performing a Rolling Restart of a MySQL Cluster * mysql-cluster-event-reports:: Event Reports Generated in MySQL Cluster * mysql-cluster-logs-ndb-messages:: MySQL Cluster Log Messages * mysql-cluster-single-user-mode:: MySQL Cluster Single User Mode * mysql-cluster-sql-statements:: Quick Reference: MySQL Cluster SQL Statements * mysql-cluster-ndbinfo:: The `ndbinfo' MySQL Cluster Information Database * mysql-cluster-security:: MySQL Cluster Security Issues * mysql-cluster-disk-data:: MySQL Cluster Disk Data Tables * mysql-cluster-online-add-node:: Adding MySQL Cluster Data Nodes Online * mysql-cluster-privilege-distribution:: Distributed MySQL Privileges for MySQL Cluster Managing a MySQL Cluster involves a number of tasks, the first of which is to configure and start MySQL Cluster. This is covered in *Note mysql-cluster-configuration::, and *Note mysql-cluster-programs::. The next few sections cover the management of a running MySQL Cluster. For information about security issues relating to management and deployment of a MySQL Cluster, see *Note mysql-cluster-security::. There are essentially two methods of actively managing a running MySQL Cluster. The first of these is through the use of commands entered into the management client whereby cluster status can be checked, log levels changed, backups started and stopped, and nodes stopped and started. The second method involves studying the contents of the cluster log `ndb_NODE_ID_cluster.log'; this is usually found in the management server's `DataDir' directory, but this location can be overridden using the `LogDestination' option. (Recall that NODE_ID represents the unique identifier of the node whose activity is being logged.) The cluster log contains event reports generated by *Note `ndbd': mysql-cluster-programs-ndbd. It is also possible to send cluster log entries to a Unix system log. Some aspects of the cluster's operation can be also be monitored from an SQL node using the *Note `SHOW ENGINE NDB STATUS': show-engine. statement. In MySQL Cluster NDB 7.1.1 and later, detailed information about cluster operations is available in real time through an SQL interface using the *Note `ndbinfo': mysql-cluster-ndbinfo. database. For more information, see *Note mysql-cluster-ndbinfo::. MySQL Enterprise Monitor can also be used to monitor MySQL Servers that are part of a MySQL Cluster deployment. MySQL Enterprise Monitor 2.3, added a MySQL Cluster advisor, including a set of graphs providing information on MySQL Cluster resources, and defining rules for alerts on key information from data nodes such as `DataMemory' usage. This information is made available to MySQL Enterprise Monitor 2.3 or later by any MySQL Server which is connected to the MySQL Cluster, using *Note `ndbinfo': mysql-cluster-ndbinfo. The advisor could be run against a single MySQL Server in the Cluster, or against a pair in order to provide a higher level of availability for the monitoring service. For more information, see the `MySQL Enterprise Monitor 2.3 Manual' (http://dev.mysql.com/doc/mysql-monitor/2.3/en/index.html). MySQL Cluster Manager provides an advanced command-line interface that simplifies many otherwise complex MySQL Cluster management tasks, such as starting, stoppping, or restarting a MySQL Cluster with a large number of nodes. The MySQL Cluster Manager client also supports commands for getting and setting the values of most node configuration parameters as well as *Note `mysqld': mysqld. server options and variables relating to MySQL Cluster. MySQL Cluster Manager 1.1 provides support for adding data nodes online. See the `MySQL Cluster Manager 1.1 User Manual' (http://dev.mysql.com/doc/mysql-cluster-manager/1.1/en/), for more information.  File: manual.info, Node: mysql-cluster-start-phases, Next: mysql-cluster-mgm-client-commands, Prev: mysql-cluster-management, Up: mysql-cluster-management 17.5.1 Summary of MySQL Cluster Start Phases -------------------------------------------- This section provides a simplified outline of the steps involved when MySQL Cluster data nodes are started. More complete information can be found in MySQL Cluster Start Phases (http://dev.mysql.com/doc/ndbapi/en/ndb-internals-start-phases.html), in the ``NDB' Internals Guide'. These phases are the same as those reported in the output from the `NODE_ID STATUS' command in the management client (see *Note mysql-cluster-mgm-client-commands::). In MySQL Cluster NDB 7.1.1 and later, these start phases are also reported in the `start_phase' column of the *Note `ndbinfo.nodes': mysql-cluster-ndbinfo-nodes. table. Start types There are several different startup types and modes, as shown in the following list: * Initial start The cluster starts with a clean file system on all data nodes. This occurs either when the cluster started for the very first time, or when all data nodes are restarted using the `--initial' option. *Note*: Disk Data files are not removed when restarting a node using `--initial'. * System restart The cluster starts and reads data stored in the data nodes. This occurs when the cluster has been shut down after having been in use, when it is desired for the cluster to resume operations from the point where it left off. * Node restart This is the online restart of a cluster node while the cluster itself is running. * Initial node restart This is the same as a node restart, except that the node is reinitialized and started with a clean file system. Setup and initialization (phase -1) Prior to startup, each data node (*Note `ndbd': mysql-cluster-programs-ndbd. process) must be initialized. Initialization consists of the following steps: 1. Obtain a node ID 2. Fetch configuration data 3. Allocate ports to be used for inter-node communications 4. Allocate memory according to settings obtained from the configuration file When a data node or SQL node first connects to the management node, it reserves a cluster node ID. To make sure that no other node allocates the same node ID, this ID is retained until the node has managed to connect to the cluster and at least one *Note `ndbd': mysql-cluster-programs-ndbd. reports that this node is connected. This retention of the node ID is guarded by the connection between the node in question and *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. Normally, in the event of a problem with the node, the node disconnects from the management server, the socket used for the connection is closed, and the reserved node ID is freed. However, if a node is disconnected abruptly--for example, due to a hardware failure in one of the cluster hosts, or because of network issues--the normal closing of the socket by the operating system may not take place. In this case, the node ID continues to be reserved and not released until a TCP timeout occurs 10 or so minutes later. To take care of this problem, you can use `PURGE STALE SESSIONS'. Running this statement forces all reserved node IDs to be checked; any that are not being used by nodes actually connected to the cluster are then freed. Beginning with MySQL 5.1.11, timeout handling of node ID assignments is implemented. This performs the ID usage checks automatically after approximately 20 seconds, so that `PURGE STALE SESSIONS' should no longer be necessary in a normal Cluster start. After each data node has been initialized, the cluster startup process can proceed. The stages which the cluster goes through during this process are listed here: * Phase 0 The `NDBFS' and `NDBCNTR' blocks start (see `NDB' Kernel Blocks (http://dev.mysql.com/doc/ndbapi/en/ndb-internals-kernel-blocks.html)). Data node file systems are cleared on those data nodes that were started with `--initial' option. * Phase 1 In this stage, all remaining *Note `NDB': mysql-cluster. kernel blocks are started. MySQL Cluster connections are set up, inter-block communications are established, and heartbeats are started. In the case of a node restart, API node connections are also checked. *Note*: When one or more nodes hang in Phase 1 while the remaining node or nodes hang in Phase 2, this often indicates network problems. One possible cause of such issues is one or more cluster hosts having multiple network interfaces. Another common source of problems causing this condition is the blocking of TCP/IP ports needed for communications between cluster nodes. In the latter case, this is often due to a misconfigured firewall. * Phase 2 The `NDBCNTR' kernel block checks the states of all existing nodes. The master node is chosen, and the cluster schema file is initialized. * Phase 3 The `DBLQH' and `DBTC' kernel blocks set up communications between them. The startup type is determined; if this is a restart, the `DBDIH' block obtains permission to perform the restart. * Phase 4 For an initial start or initial node restart, the redo log files are created. The number of these files is equal to `NoOfFragmentLogFiles'. For a system restart: * Read schema or schemas. * Read data from the local checkpoint. * Apply all redo information until the latest restorable global checkpoint has been reached. For a node restart, find the tail of the redo log. * Phase 5 Most of the database-related portion of a data node start is performed during this phase. For an initial start or system restart, a local checkpoint is executed, followed by a global checkpoint. Periodic checks of memory usage begin during this phase, and any required node takeovers are performed. * Phase 6 In this phase, node groups are defined and set up. * Phase 7 The arbitrator node is selected and begins to function. The next backup ID is set, as is the backup disk write speed. Nodes reaching this start phase are marked as `Started'. It is now possible for API nodes (including SQL nodes) to connect to the cluster. * Phase 8 If this is a system restart, all indexes are rebuilt (by `DBDIH'). * Phase 9 The node internal startup variables are reset. * Phase 100 (_OBSOLETE_) Formerly, it was at this point during a node restart or initial node restart that API nodes could connect to the node and begin to receive events. Currently, this phase is empty. * Phase 101 At this point in a node restart or initial node restart, event delivery is handed over to the node joining the cluster. The newly-joined node takes over responsibility for delivering its primary data to subscribers. This phase is also referred to as _`SUMA' handover phase_. After this process is completed for an initial start or system restart, transaction handling is enabled. For a node restart or initial node restart, completion of the startup process means that the node may now act as a transaction coordinator.  File: manual.info, Node: mysql-cluster-mgm-client-commands, Next: mysql-cluster-backup, Prev: mysql-cluster-start-phases, Up: mysql-cluster-management 17.5.2 Commands in the MySQL Cluster Management Client ------------------------------------------------------ In addition to the central configuration file, a cluster may also be controlled through a command-line interface available through the management client *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. This is the primary administrative interface to a running cluster. Commands for the event logs are given in *Note mysql-cluster-event-reports::; commands for creating backups and restoring from them are provided in *Note mysql-cluster-backup::. The management client has the following basic commands. In the listing that follows, NODE_ID denotes either a database node ID or the keyword `ALL', which indicates that the command should be applied to all of the cluster's data nodes. * `HELP' Displays information on all available commands. * `SHOW' Displays information on the cluster's status. Possible node status values include `UNKNOWN', `NO_CONTACT', `NOT_STARTED', `STARTING', `STARTED', `SHUTTING_DOWN', and `RESTARTING'. Beginning with MySQL Cluster NDB 6.2.8 and MySQL Cluster NDB 6.3.6, the output from this command indicates when the cluster is in single user mode (status `SINGLE USER MODE'). Prior to MySQL Cluster NDB 7.0.26 and MySQL Cluster NDB 7.1.5, in a cluster having multiple management nodes, this command displayed information only for data nodes that were actually connected to the current management server; in addition, management servers could not find each other until all nodes had been started. Beginning with these versions, such issues are fixed (see Bug#12352191), and management nodes can be additionally be reported with status `RESUME' or `CONNECTED'. * `NODE_ID START' Brings online the data node identified by NODE_ID (or all data nodes). `ALL START' works on all data nodes only, and does not affect management nodes. *Important*: To use this command to bring a data node online, the data node must have been started using *Note `ndbd `--nostart'': mysql-cluster-programs-ndbd. or *Note `ndbd `-n'': mysql-cluster-programs-ndbd. * `NODE_ID STOP [-a] [-f]' Stops the data or management node identified by NODE_ID. Note that `ALL STOP' works to stop all data nodes only, and does not affect management nodes. A node affected by this command disconnects from the cluster, and its associated *Note `ndbd': mysql-cluster-programs-ndbd. or *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. process terminates. The `-a' option causes the node to be stopped immediately, without waiting for the completion of any pending transactions. Normally, `STOP' fails if the result would cause an incomplete cluster. The `-f' option, added in MySQL Cluster NDB 7.0.19 and MySQL Cluster NDB 7.1.8, forces the node to shut down without checking for this. If this option is used and the result is an incomplete cluster, the cluster immediately shuts down. *Warning*: Use of the `-a' option also disables the safety check otherwise performed when `STOP' is invoked to insure that stopping the node does not cause an incomplete cluster. In other words, you should exercise extreme care when using the `-a' option with the `STOP' command, due to the fact that this option makes it possible for the cluster to undergo a forced shutdown because it no longer has a complete copy of all data stored in *Note `NDB': mysql-cluster. * `NODE_ID RESTART [-n] [-i] [-a] [-f]' Restarts the data node identified by NODE_ID (or all data nodes). Using the `-i' option with `RESTART' causes the data node to perform an initial restart; that is, the node's file system is deleted and recreated. The effect is the same as that obtained from stopping the data node process and then starting it again using *Note `ndbd `--initial'': mysql-cluster-programs-ndbd. from the system shell. Note that backup files and Disk Data files are not removed when this option is used. Using the `-n' option causes the data node process to be restarted, but the data node is not actually brought online until the appropriate `START' command is issued. The effect of this option is the same as that obtained from stopping the data node and then starting it again using *Note `ndbd `--nostart'': mysql-cluster-programs-ndbd. or *Note `ndbd `-n'': mysql-cluster-programs-ndbd. from the system shell. Using the `-a' causes all current transactions relying on this node to be aborted. No GCP check is done when the node rejoins the cluster. Normally, `RESTART' fails if taking the node offline would result in an incomplete cluster. The `-f' option, added in MySQL Cluster NDB 7.0.19 and MySQL Cluster NDB 7.1.8, forces the node to restart without checking for this. If this option is used and the result is an incomplete cluster, the entire cluster is restarted. * `NODE_ID STATUS' Displays status information for the data node identified by NODE_ID (or for all data nodes). Beginning with MySQL Cluster NDB 6.2.8 and MySQL Cluster NDB 6.3.6, the output from this command indicates when the cluster is in single user mode. * `NODE_ID REPORT REPORT-TYPE' Displays a report of type REPORT-TYPE for the data node identified by NODE_ID, or for all data nodes using `ALL'. Currently, there are two accepted values for REPORT-TYPE: * `BackupStatus' provides a status report on a cluster backup in progress * `MemoryUsage' displays how much data memory and index memory is being used by each data node as shown in this example: ndb_mgm> ALL REPORT MEMORY Node 1: Data usage is 5%(177 32K pages of total 3200) Node 1: Index usage is 0%(108 8K pages of total 12832) Node 2: Data usage is 5%(177 32K pages of total 3200) Node 2: Index usage is 0%(108 8K pages of total 12832) In MySQL Cluster NDB 7.1.1 and later, this information is also available from the *Note `ndbinfo.memoryusage': mysql-cluster-ndbinfo-memoryusage. table. REPORT-TYPE is case-insensitive and `fuzzy'; for `MemoryUsage', you can use `MEMORY' (as shown in the prior example), `memory', or even simply `MEM' (or `mem'). You can abbreviate `BackupStatus' in a similar fashion. The `REPORT' command was introduced in MySQL Cluster NDB 6.2.3 and MySQL Cluster NDB 6.3.0. * `ENTER SINGLE USER MODE NODE_ID' Enters single user mode, whereby only the MySQL server identified by the node ID NODE_ID is permitted to access the database. Currently, it is not possible for data nodes to join a MySQL Cluster while it is running in single user mode. (Bug#20395) * `EXIT SINGLE USER MODE' Exits single user mode, enabling all SQL nodes (that is, all running *Note `mysqld': mysqld. processes) to access the database. *Note*: It is possible to use `EXIT SINGLE USER MODE' even when not in single user mode, although the command has no effect in this case. * `QUIT', `EXIT' Terminates the management client. This command does not affect any nodes connected to the cluster. * `SHUTDOWN' Shuts down all cluster data nodes and management nodes. To exit the management client after this has been done, use `EXIT' or `QUIT'. This command does _not_ shut down any SQL nodes or API nodes that are connected to the cluster. * `CREATE NODEGROUP NODEID[, NODEID, ...]' Creates a new MySQL Cluster node group and causes data nodes to join it. This command is used after adding new data nodes online to a MySQL Cluster, and causes them to join a new node group and thus to begin participating fully in the cluster. The command takes as its sole parameter a comma-separated list of node IDs--these are the IDs of the nodes just added and started that are to join the new node group. The number of nodes must be the same as the number of nodes in each node group that is already part of the cluster (each MySQL Cluster node group must have the same number of nodes). In other words, if the MySQL Cluster has 2 node groups of 2 data nodes each, then the new node group must also have 2 data nodes. The node group ID of the new node group created by this command is determined automatically, and always the next highest unused node group ID in the cluster; it is not possible to set it manually. This command was introduced in MySQL Cluster NDB 6.4.0. For more information, see *Note mysql-cluster-online-add-node::. * `DROP NODEGROUP NODEGROUP_ID' Drops the MySQL Cluster node group with the given NODEGROUP_ID. This command can be used to drop a node group from a MySQL Cluster. `DROP NODEGROUP' takes as its sole argument the node group ID of the node group to be dropped. `DROP NODEGROUP' acts only to remove the data nodes in the effected node group from that node group. It does not stop data nodes, assign them to a different node group, or remove them from the cluster's configuration. A data node that does not belong to a node group is indicated in the output of the management client `SHOW' command with `no nodegroup' in place of the node group ID, like this (indicated using bold text): id=3 @10.100.2.67 (5.1.56-ndb-7.1.16, *no nodegroup*) Prior to MySQL Cluster NDB 7.0.4, the `SHOW' output was not updated correctly following `DROP NODEGROUP'. (Bug#43413) `DROP NODEGROUP' works only when all data nodes in the node group to be dropped are completely empty of any table data and table definitions. Since there is currently no way using *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. or the *Note `mysql': mysql. client to remove all data from a specific data node or node group, this means that the command succeeds only in the two following cases: 1. After issuing `CREATE NODEGROUP' in the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client, but before issuing any *Note `ALTER ONLINE TABLE ... REORGANIZE PARTITION': alter-table. statements in the *Note `mysql': mysql. client. 2. After dropping all *Note `NDBCLUSTER': mysql-cluster. tables using *Note `DROP TABLE': drop-table. *Note `TRUNCATE TABLE': truncate-table. does not work for this purpose because this removes only the table data; the data nodes continue to store an *Note `NDBCLUSTER': mysql-cluster. table's definition until a *Note `DROP TABLE': drop-table. statement is issued that causes the table metadata to be dropped. `DROP NODEGROUP' was introduced in MySQL Cluster NDB 6.4.0. For more information, see *Note mysql-cluster-online-add-node::.  File: manual.info, Node: mysql-cluster-backup, Next: mysql-cluster-rolling-restart, Prev: mysql-cluster-mgm-client-commands, Up: mysql-cluster-management 17.5.3 Online Backup of MySQL Cluster ------------------------------------- * Menu: * mysql-cluster-backup-concepts:: MySQL Cluster Backup Concepts * mysql-cluster-backup-using-management-client:: Using The MySQL Cluster Management Client to Create a Backup * mysql-cluster-backup-configuration:: Configuration for MySQL Cluster Backups * mysql-cluster-backup-troubleshooting:: MySQL Cluster Backup Troubleshooting The next few sections describe how to prepare for and then to create a MySQL Cluster backup using the functionality for this purpose found in the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. management client. To distinguish this type of backup from a backup made using *Note `mysqldump': mysqldump, we sometimes refer to it as a `native' MySQL Cluster backup. (For information about the creation of backups with *Note `mysqldump': mysqldump, see *Note mysqldump::.) Restoration of MySQL Cluster backups is done using the *Note `ndb_restore': mysql-cluster-programs-ndb-restore. utility provided with the MySQL Cluster distribution; for information about *Note `ndb_restore': mysql-cluster-programs-ndb-restore. and its use in restoring MySQL Cluster backups, see *Note mysql-cluster-programs-ndb-restore::.  File: manual.info, Node: mysql-cluster-backup-concepts, Next: mysql-cluster-backup-using-management-client, Prev: mysql-cluster-backup, Up: mysql-cluster-backup 17.5.3.1 MySQL Cluster Backup Concepts ...................................... A backup is a snapshot of the database at a given time. The backup consists of three main parts: * Metadata The names and definitions of all database tables * Table records The data actually stored in the database tables at the time that the backup was made * Transaction log A sequential record telling how and when data was stored in the database Each of these parts is saved on all nodes participating in the backup. During backup, each node saves these three parts into three files on disk: * `BACKUP-BACKUP_ID.NODE_ID.ctl' A control file containing control information and metadata. Each node saves the same table definitions (for all tables in the cluster) to its own version of this file. * `BACKUP-BACKUP_ID-0.NODE_ID.data' A data file containing the table records, which are saved on a per-fragment basis. That is, different nodes save different fragments during the backup. The file saved by each node starts with a header that states the tables to which the records belong. Following the list of records there is a footer containing a checksum for all records. * `BACKUP-BACKUP_ID.NODE_ID.log' A log file containing records of committed transactions. Only transactions on tables stored in the backup are stored in the log. Nodes involved in the backup save different records because different nodes host different database fragments. In the listing above, BACKUP_ID stands for the backup identifier and NODE_ID is the unique identifier for the node creating the file.  File: manual.info, Node: mysql-cluster-backup-using-management-client, Next: mysql-cluster-backup-configuration, Prev: mysql-cluster-backup-concepts, Up: mysql-cluster-backup 17.5.3.2 Using The MySQL Cluster Management Client to Create a Backup ..................................................................... Before starting a backup, make sure that the cluster is properly configured for performing one. (See *Note mysql-cluster-backup-configuration::.) The `START BACKUP' command is used to create a backup: START BACKUP [BACKUP_ID] [WAIT_OPTION] [SNAPSHOT_OPTION] WAIT_OPTION: WAIT {STARTED | COMPLETED} | NOWAIT SNAPSHOT_OPTION: SNAPSHOTSTART | SNAPSHOTEND Successive backups are automatically identified sequentially, so the BACKUP_ID, an integer greater than or equal to 1, is optional; if it is omitted, the next available value is used. If an existing BACKUP_ID value is used, the backup fails with the error `Backup failed: file already exists'. If used, the BACKUP_ID must follow `START BACKUP' immediately, before any other options are used. Prior to MySQL Cluster NDB 6.2.17, 6.3.23, and 6.4.3, backup IDs greater than 2147483648 (2^31) were not supported correctly. (Bug#43042) Beginning with these versions, the maximum possible backup ID is 4294967296 (2^32). *Note*: Prior to MySQL Cluster NDB 7.0.5, when starting a backup using *Note `ndb_mgm -e "START BACKUP"': mysql-cluster-programs-ndb-mgm, the BACKUP_ID was required. (Bug#31754) The WAIT_OPTION can be used to determine when control is returned to the management client after a `START BACKUP' command is issued, as shown in the following list: * If `NOWAIT' is specified, the management client displays a prompt immediately, as seen here: ndb_mgm> START BACKUP NOWAIT ndb_mgm> In this case, the management client can be used even while it prints progress information from the backup process. * With `WAIT STARTED' the management client waits until the backup has started before returning control to the user, as shown here: ndb_mgm> START BACKUP WAIT STARTED Waiting for started, this may take several minutes Node 2: Backup 3 started from node 1 ndb_mgm> * WAIT COMPLETED causes the management client to wait until the backup process is complete before returning control to the user. `WAIT COMPLETED' is the default. Beginning with MySQL Cluster NDB 6.4.0, a SNAPSHOT_OPTION can be used to determine whether the backup matches the state of the cluster when `START BACKUP' was issued, or when it was completed. `SNAPSHOTSTART' causes the backup to match the state of the cluster when the backup began; `SNAPSHOTEND' causes the backup to reflect the state of the cluster when the backup was finished. `SNAPSHOTEND' is the default, and matches the behavior found in previous MySQL Cluster releases. *Note*: If you use the `SNAPSHOTSTART' option with `START BACKUP', and the `CompressedBackup' parameter is enabled, only the data and control files are compressed--the log file is not compressed. If both a WAIT_OPTION and a SNAPSHOT_OPTION are used, they may be specified in either order. For example, all of the following commands are valid, assuming that there is no existing backup having 4 as its ID: START BACKUP WAIT STARTED SNAPSHOTSTART START BACKUP SNAPSHOTSTART WAIT STARTED START BACKUP 4 WAIT COMPLETED SNAPSHOTSTART START BACKUP SNAPSHOTEND WAIT COMPLETED START BACKUP 4 NOWAIT SNAPSHOTSTART The procedure for creating a backup consists of the following steps: 1. Start the management client (*Note `ndb_mgm': mysql-cluster-programs-ndb-mgm.), if it not running already. 2. Execute the START BACKUP command. This produces several lines of output indicating the progress of the backup, as shown here: ndb_mgm> START BACKUP Waiting for completed, this may take several minutes Node 2: Backup 1 started from node 1 Node 2: Backup 1 started from node 1 completed StartGCP: 177 StopGCP: 180 #Records: 7362 #LogRecords: 0 Data: 453648 bytes Log: 0 bytes ndb_mgm> 3. When the backup has started the management client displays this message: Backup BACKUP_ID started from node NODE_ID BACKUP_ID is the unique identifier for this particular backup. This identifier is saved in the cluster log, if it has not been configured otherwise. NODE_ID is the identifier of the management server that is coordinating the backup with the data nodes. At this point in the backup process the cluster has received and processed the backup request. It does not mean that the backup has finished. An example of this statement is shown here: Node 2: Backup 1 started from node 1 4. The management client indicates with a message like this one that the backup has started: Backup BACKUP_ID started from node NODE_ID completed As is the case for the notification that the backup has started, BACKUP_ID is the unique identifier for this particular backup, and NODE_ID is the node ID of the management server that is coordinating the backup with the data nodes. This output is accompanied by additional information including relevant global checkpoints, the number of records backed up, and the size of the data, as shown here: Node 2: Backup 1 started from node 1 completed StartGCP: 177 StopGCP: 180 #Records: 7362 #LogRecords: 0 Data: 453648 bytes Log: 0 bytes It is also possible to perform a backup from the system shell by invoking *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. with the `-e' or `--execute' option, as shown in this example: shell> ndb_mgm -e "START BACKUP 6 WAIT COMPLETED SNAPSHOTSTART" When using `START BACKUP' in this way, you must specify the backup ID. Cluster backups are created by default in the `BACKUP' subdirectory of the `DataDir' on each data node. This can be overridden for one or more data nodes individually, or for all cluster data nodes in the `config.ini' file using the `BackupDataDir' configuration parameter. The backup files created for a backup with a given BACKUP_ID are stored in a subdirectory named `BACKUP-BACKUP_ID' in the backup directory. To abort a backup that is already in progress: 1. Start the management client. 2. Execute this command: ndb_mgm> ABORT BACKUP BACKUP_ID The number BACKUP_ID is the identifier of the backup that was included in the response of the management client when the backup was started (in the message `Backup BACKUP_ID started from node MANAGEMENT_NODE_ID'). 3. The management client will acknowledge the abort request with `Abort of backup BACKUP_ID ordered'. *Note*: At this point, the management client has not yet received a response from the cluster data nodes to this request, and the backup has not yet actually been aborted. 4. After the backup has been aborted, the management client will report this fact in a manner similar to what is shown here: Node 1: Backup 3 started from 5 has been aborted. Error: 1321 - Backup aborted by user request: Permanent error: User defined error Node 3: Backup 3 started from 5 has been aborted. Error: 1323 - 1323: Permanent error: Internal error Node 2: Backup 3 started from 5 has been aborted. Error: 1323 - 1323: Permanent error: Internal error Node 4: Backup 3 started from 5 has been aborted. Error: 1323 - 1323: Permanent error: Internal error In this example, we have shown sample output for a cluster with 4 data nodes, where the sequence number of the backup to be aborted is `3', and the management node to which the cluster management client is connected has the node ID `5'. The first node to complete its part in aborting the backup reports that the reason for the abort was due to a request by the user. (The remaining nodes report that the backup was aborted due to an unspecified internal error.) *Note*: There is no guarantee that the cluster nodes respond to an `ABORT BACKUP' command in any particular order. The `Backup BACKUP_ID started from node MANAGEMENT_NODE_ID has been aborted' messages mean that the backup has been terminated and that all files relating to this backup have been removed from the cluster file system. It is also possible to abort a backup in progress from a system shell using this command: shell> ndb_mgm -e "ABORT BACKUP BACKUP_ID" *Note*: If there is no backup having the ID BACKUP_ID running when an `ABORT BACKUP' is issued, the management client makes no response, nor is it indicated in the cluster log that an invalid abort command was sent.  File: manual.info, Node: mysql-cluster-backup-configuration, Next: mysql-cluster-backup-troubleshooting, Prev: mysql-cluster-backup-using-management-client, Up: mysql-cluster-backup 17.5.3.3 Configuration for MySQL Cluster Backups ................................................ Five configuration parameters are essential for backup: * `BackupDataBufferSize' The amount of memory used to buffer data before it is written to disk. * `BackupLogBufferSize' The amount of memory used to buffer log records before these are written to disk. * `BackupMemory' The total memory allocated in a data node for backups. This should be the sum of the memory allocated for the backup data buffer and the backup log buffer. * `BackupWriteSize' The default size of blocks written to disk. This applies for both the backup data buffer and the backup log buffer. * `BackupMaxWriteSize' The maximum size of blocks written to disk. This applies for both the backup data buffer and the backup log buffer. More detailed information about these parameters can be found in Backup Parameters.  File: manual.info, Node: mysql-cluster-backup-troubleshooting, Prev: mysql-cluster-backup-configuration, Up: mysql-cluster-backup 17.5.3.4 MySQL Cluster Backup Troubleshooting ............................................. If an error code is returned when issuing a backup request, the most likely cause is insufficient memory or disk space. You should check that there is enough memory allocated for the backup. *Important*: If you have set `BackupDataBufferSize' and `BackupLogBufferSize' and their sum is greater than 4MB, then you must also set `BackupMemory' as well. You should also make sure that there is sufficient space on the hard drive partition of the backup target. *Note `NDB': mysql-cluster. does not support repeatable reads, which can cause problems with the restoration process. Although the backup process is `hot', restoring a MySQL Cluster from backup is not a 100% `hot' process. This is due to the fact that, for the duration of the restore process, running transactions get nonrepeatable reads from the restored data. This means that the state of the data is inconsistent while the restore is in progress.  File: manual.info, Node: mysql-cluster-rolling-restart, Next: mysql-cluster-event-reports, Prev: mysql-cluster-backup, Up: mysql-cluster-management 17.5.4 Performing a Rolling Restart of a MySQL Cluster ------------------------------------------------------ This section discusses how to perform a _rolling restart_ of a MySQL Cluster installation, so called because it involves stopping and starting (or restarting) each node in turn, so that the cluster itself remains operational. This is often done as part of a _rolling upgrade_ or _rolling downgrade_, where high availability of the cluster is mandatory and no downtime of the cluster as a whole is permissible. Where we refer to upgrades, the information provided here also generally applies to downgrades as well. There are a number of reasons why a rolling restart might be desirable. These are described in the next few paragraphs. Configuration change To make a change in the cluster's configuration, such as adding an SQL node to the cluster, or setting a configuration parameter to a new value. MySQL Cluster software upgrade or downgrade To upgrade the cluster to a newer version of the MySQL Cluster software (or to downgrade it to an older version). This is usually referred to as a `rolling upgrade' (or `rolling downgrade', when reverting to an older version of MySQL Cluster). Change on node host To make changes in the hardware or operating system on which one or more MySQL Cluster node processes are running. System reset (cluster reset) To reset the cluster because it has reached an undesirable state. In such cases it is often desirable to reload the data and metadata of one or more data nodes. This can be done in any of three ways: * Start each data node process (*Note `ndbd': mysql-cluster-programs-ndbd, or possibly *Note `ndbmtd': mysql-cluster-programs-ndbmtd. in MySQL Cluster NDB 7.0 and later) with the `--initial' option, which forces the data node to clear its file system and to reload all MySQL Cluster data and metadata from the other data nodes. * Create a backup using the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client `BACKUP' command prior to performing the restart. Following the upgrade, restore the node or nodes using *Note `ndb_restore': mysql-cluster-programs-ndb-restore. See *Note mysql-cluster-backup::, and *Note mysql-cluster-programs-ndb-restore::, for more information. * Use *Note `mysqldump': mysqldump. to create a backup prior to the upgrade; afterward, restore the dump using *Note `LOAD DATA INFILE': load-data. Resource Recovery To free memory previously allocated to a table by successive *Note `INSERT': insert. and *Note `DELETE': delete. operations, for re-use by other MySQL Cluster tables. The process for performing a rolling restart may be generalized as follows: 1. Stop all cluster management nodes (*Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. processes), reconfigure them, then restart them. 2. Stop, reconfigure, then restart each cluster data node (*Note `ndbd': mysql-cluster-programs-ndbd. process) in turn. 3. Stop, reconfigure, then restart each cluster SQL node (*Note `mysqld': mysqld. process) in turn. The specifics for implementing a given rolling upgrade depend upon the changes being made. A more detailed view of the process is presented here: MySQL Cluster Rolling Restarts (By Type) In the previous diagram, the *Stop* and *Start* steps indicate that the process must be stopped completely using a shell command (such as *Note `kill': kill. on most Unix systems) or the management client `STOP' command, then started again from a system shell by invoking the *Note `ndbd': mysql-cluster-programs-ndbd. or *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. executable as appropriate. On Windows (MySQL Cluster NDB 7.1.3 and later), you can also use the system `NET START' and `NET STOP' commands or the Windows Service Manager to start and stop nodes which have been installed as Windows services (see *Note mysql-cluster-install-windows-service::). *Restart* indicates that the process may be restarted using the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. management client `RESTART' command (see *Note mysql-cluster-mgm-client-commands::). Prior to MySQL Cluster NDB 6.3.29 and MySQL Cluster NDB 7.0.10 When performing an upgrade or downgrade of the cluster software, you must upgrade or downgrade the management nodes first, then the data nodes, and finally the SQL nodes. Doing so in any other order may leave the cluster in an unusable state. MySQL Cluster NDB 6.3.29 and later; MySQL Cluster NDB 7.0.10 and later MySQL Cluster supports a more flexible order for upgrading the cluster nodes. When upgrading a cluster running MySQL Cluster NDB 6.3.29 or later, or a cluster that is running MySQL Cluster NDB 7.0.10 or later, you may upgrade API nodes (including SQL nodes) before upgrading the management nodes, data nodes, or both. In other words, you are permitted to upgrade the API and SQL nodes in any order. This is subject to the following provisions: * This functionality is intended for use as part of an online upgrade only. A mix of node binaries from different MySQL Cluster releases is neither intended nor supported for constant, long-term use in a production setting. * All management nodes must be upgraded before any data nodes are upgraded. This remains true regardless of the order in which you upgrade the cluster's API and SQL nodes. * For MySQL Cluster NDB 6.3, the ability to upgrade API nodes in any order relative to upgading management nodes and data nodes is supported only for MySQL Cluster NDB 6.3.29 and later; for MySQL Cluster NDB 7.0, it supported only for MySQL Cluster NDB 7.0.10 and later. This means that, if you are upgrading from a MySQL Cluster NDB 6.3 release to a MySQL Cluster NDB 7.0 release, the `old' *Note `NDB': mysql-cluster. engine version must be 6.3.29 or later, and the `new' *Note `NDB': mysql-cluster. engine version must be 7.0.10 or later. * When upgrading the cluster from a MySQL Cluster NDB 6.3 release to a MySQL Cluster NDB 7.0 release: Once you have started upgrading the API nodes, you should not perform DDL operations until all management nodes and data nodes have been upgraded. DML operations should be unaffected, and can continue while the upgrade is in progress. However, it is possible to perform DDL from an `old' (NDB 6.3 version) API node as long as the master data node is also running the `old' version of MySQL Cluster. You should keep in mind that a data node restart could result in the master node running a `new' (NDB 7.0 version) binary while one or more data nodes are still using the `old' (NDB 6.3) version; in this situation, no DDL can be performed from _any_ API node, because the master data node is no longer using an NDB 6.3 binary, but the cluster still contains nodes which are not yet using NDB 7.0. For this reason, we recommend that you avoid performing DDL at any time while the upgrade is in progress. * Features specific to the `new' version must not be used until all management nodes and data nodes have been upgraded. This also applies to any MySQL Server version change that may apply, in addition to the NDB engine version change, so do not forget to take this into account when planning the upgrade. (This is true for online upgrades of MySQL Cluster in general.) See also Bug#48528 and Bug#49163. MySQL Cluster NDB 7.0.24 and later; MySQL Cluster NDB 7.1.13 and later When performing a rolling restart to update the cluster's configuration, you can use the `config_generation' column of the *Note `ndbinfo.nodes': mysql-cluster-ndbinfo-nodes. table to keep track of which data nodes have been successfully restarted with the new configuration. See *Note mysql-cluster-ndbinfo-nodes::.  File: manual.info, Node: mysql-cluster-event-reports, Next: mysql-cluster-logs-ndb-messages, Prev: mysql-cluster-rolling-restart, Up: mysql-cluster-management 17.5.5 Event Reports Generated in MySQL Cluster ----------------------------------------------- * Menu: * mysql-cluster-logging-management-commands:: MySQL Cluster Logging Management Commands * mysql-cluster-log-events:: MySQL Cluster Log Events * mysql-cluster-log-statistics:: Using `CLUSTERLOG STATISTICS' in the MySQL Cluster Management Client In this section, we discuss the types of event logs provided by MySQL Cluster, and the types of events that are logged. MySQL Cluster provides two types of event log: * The _cluster log_, which includes events generated by all cluster nodes. The cluster log is the log recommended for most uses because it provides logging information for an entire cluster in a single location. By default, the cluster log is saved to a file named `ndb_NODE_ID_cluster.log', (where NODE_ID is the node ID of the management server) in the same directory where the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. binary resides. Cluster logging information can also be sent to `stdout' or a `syslog' facility in addition to or instead of being saved to a file, as determined by the values set for the `DataDir' and `LogDestination' configuration parameters. See *Note mysql-cluster-mgm-definition::, for more information about these parameters. * _Node logs_ are local to each node. Output generated by node event logging is written to the file `ndb_NODE_ID_out.log' (where NODE_ID is the node's node ID) in the node's `DataDir'. Node event logs are generated for both management nodes and data nodes. Node logs are intended to be used only during application development, or for debugging application code. Both types of event logs can be set to log different subsets of events. Each reportable event can be distinguished according to three different criteria: * _Category_: This can be any one of the following values: `STARTUP', `SHUTDOWN', `STATISTICS', `CHECKPOINT', `NODERESTART', `CONNECTION', `ERROR', or `INFO'. * _Priority_: This is represented by one of the numbers from 1 to 15 inclusive, where 1 indicates `most important' and 15 `least important.' * _Severity Level_: This can be any one of the following values: `ALERT', `CRITICAL', `ERROR', `WARNING', `INFO', or `DEBUG'. Both the cluster log and the node log can be filtered on these properties. The format used in the cluster log is as shown here: 2007-01-26 19:35:55 [MgmSrvr] INFO -- Node 1: Data usage is 2%(60 32K pages of total 2560) 2007-01-26 19:35:55 [MgmSrvr] INFO -- Node 1: Index usage is 1%(24 8K pages of total 2336) 2007-01-26 19:35:55 [MgmSrvr] INFO -- Node 1: Resource 0 min: 0 max: 639 curr: 0 2007-01-26 19:35:55 [MgmSrvr] INFO -- Node 2: Data usage is 2%(76 32K pages of total 2560) 2007-01-26 19:35:55 [MgmSrvr] INFO -- Node 2: Index usage is 1%(24 8K pages of total 2336) 2007-01-26 19:35:55 [MgmSrvr] INFO -- Node 2: Resource 0 min: 0 max: 639 curr: 0 2007-01-26 19:35:55 [MgmSrvr] INFO -- Node 3: Data usage is 2%(58 32K pages of total 2560) 2007-01-26 19:35:55 [MgmSrvr] INFO -- Node 3: Index usage is 1%(25 8K pages of total 2336) 2007-01-26 19:35:55 [MgmSrvr] INFO -- Node 3: Resource 0 min: 0 max: 639 curr: 0 2007-01-26 19:35:55 [MgmSrvr] INFO -- Node 4: Data usage is 2%(74 32K pages of total 2560) 2007-01-26 19:35:55 [MgmSrvr] INFO -- Node 4: Index usage is 1%(25 8K pages of total 2336) 2007-01-26 19:35:55 [MgmSrvr] INFO -- Node 4: Resource 0 min: 0 max: 639 curr: 0 2007-01-26 19:39:42 [MgmSrvr] INFO -- Node 4: Node 9 Connected 2007-01-26 19:39:42 [MgmSrvr] INFO -- Node 1: Node 9 Connected 2007-01-26 19:39:42 [MgmSrvr] INFO -- Node 1: Node 9: API 5.1.56-ndb-7.1.16 2007-01-26 19:39:42 [MgmSrvr] INFO -- Node 2: Node 9 Connected 2007-01-26 19:39:42 [MgmSrvr] INFO -- Node 2: Node 9: API 5.1.56-ndb-7.1.16 2007-01-26 19:39:42 [MgmSrvr] INFO -- Node 3: Node 9 Connected 2007-01-26 19:39:42 [MgmSrvr] INFO -- Node 3: Node 9: API 5.1.56-ndb-7.1.16 2007-01-26 19:39:42 [MgmSrvr] INFO -- Node 4: Node 9: API 5.1.56-ndb-7.1.16 2007-01-26 19:59:22 [MgmSrvr] ALERT -- Node 2: Node 7 Disconnected 2007-01-26 19:59:22 [MgmSrvr] ALERT -- Node 2: Node 7 Disconnected Each line in the cluster log contains the following information: * A timestamp in `YYYY-MM-DD HH:MM:SS' format. * The type of node which is performing the logging. In the cluster log, this is always `[MgmSrvr]'. * The severity of the event. * The ID of the node reporting the event. * A description of the event. The most common types of events to appear in the log are connections and disconnections between different nodes in the cluster, and when checkpoints occur. In some cases, the description may contain status information.  File: manual.info, Node: mysql-cluster-logging-management-commands, Next: mysql-cluster-log-events, Prev: mysql-cluster-event-reports, Up: mysql-cluster-event-reports 17.5.5.1 MySQL Cluster Logging Management Commands .................................................. The following management commands are related to the cluster log: * `CLUSTERLOG ON' Turns the cluster log on. * `CLUSTERLOG OFF' Turns the cluster log off. * `CLUSTERLOG INFO' Provides information about cluster log settings. * `NODE_ID CLUSTERLOG CATEGORY=THRESHOLD' Logs CATEGORY events with priority less than or equal to THRESHOLD in the cluster log. * `CLUSTERLOG FILTER SEVERITY_LEVEL' Toggles cluster logging of events of the specified SEVERITY_LEVEL. The following table describes the default setting (for all data nodes) of the cluster log category threshold. If an event has a priority with a value lower than or equal to the priority threshold, it is reported in the cluster log. Note that events are reported per data node, and that the threshold can be set to different values on different nodes. Category Default threshold (All data nodes) `STARTUP' *7* `SHUTDOWN' *7* `STATISTICS' *7* `CHECKPOINT' *7* `NODERESTART' *7* `CONNECTION' *7* `ERROR' *15* `INFO' *7* The `STATISTICS' category can provide a great deal of useful data. See *Note mysql-cluster-log-statistics::, for more information. Thresholds are used to filter events within each category. For example, a `STARTUP' event with a priority of 3 is not logged unless the threshold for `STARTUP' is set to 3 or higher. Only events with priority 3 or lower are sent if the threshold is 3. The following table shows the event severity levels. *Note*: These correspond to Unix `syslog' levels, except for `LOG_EMERG' and `LOG_NOTICE', which are not used or mapped. *1* `ALERT' A condition that should be corrected immediately, such as a corrupted system database *2* `CRITICAL' Critical conditions, such as device errors or insufficient resources *3* `ERROR' Conditions that should be corrected, such as configuration errors *4* `WARNING' Conditions that are not errors, but that might require special handling *5* `INFO' Informational messages *6* `DEBUG' Debugging messages used for *Note `NDBCLUSTER': mysql-cluster. development Event severity levels can be turned on or off (using `CLUSTERLOG FILTER'--see above). If a severity level is turned on, then all events with a priority less than or equal to the category thresholds are logged. If the severity level is turned off then no events belonging to that severity level are logged. *Important*: Cluster log levels are set on a per *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd, per subscriber basis. This means that, in a MySQL Cluster with multiple management servers, using a `CLUSTERLOG' command in an instance of *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. connected to one management server affects only logs generated by that management server but not by any of the others. This also means that, should one of the management servers be restarted, only logs generated by that management server are affected by the resetting of log levels caused by the restart.  File: manual.info, Node: mysql-cluster-log-events, Next: mysql-cluster-log-statistics, Prev: mysql-cluster-logging-management-commands, Up: mysql-cluster-event-reports 17.5.5.2 MySQL Cluster Log Events ................................. An event report reported in the event logs has the following format: DATETIME [STRING] SEVERITY -- MESSAGE For example: 09:19:30 2005-07-24 [NDB] INFO -- Node 4 Start phase 4 completed This section discusses all reportable events, ordered by category and severity level within each category. In the event descriptions, GCP and LCP mean `Global Checkpoint' and `Local Checkpoint', respectively. *`CONNECTION' Events* These events are associated with connections between Cluster nodes. Event PrioritySeverityDescription Level data nodes connected 8 `INFO' Data nodes connected data nodes disconnected 8 `INFO' Data nodes disconnected Communication closed 8 `INFO' SQL node or data node connection closed Communication opened 8 `INFO' SQL node or data node connection opened *`CHECKPOINT' Events* The logging messages shown here are associated with checkpoints. Event PrioritySeverityDescription Level LCP stopped in calc keep 0 `ALERT' LCP stopped GCI Local checkpoint 11 `INFO' LCP on a fragment has been fragment completed completed Global checkpoint 10 `INFO' GCP finished completed Global checkpoint started 9 `INFO' Start of GCP: REDO log is written to disk Local checkpoint 8 `INFO' LCP completed normally completed Local checkpoint started 7 `INFO' Start of LCP: data written to disk *`STARTUP' Events* The following events are generated in response to the startup of a node or of the cluster and of its success or failure. They also provide information relating to the progress of the startup process, including information concerning logging activities. Event PrioritySeverityDescription Level Internal start signal 15 `INFO' Blocks received after received STTORRY completion of restart New REDO log started 10 `INFO' GCI keep X, newest restorable GCI Y New log started 10 `INFO' Log part X, start MB Y, stop MB Z Node has been refused 8 `INFO' Node cannot be included in for inclusion in the cluster due to cluster misconfiguration, inability to establish communication, or other problem data node neighbors 8 `INFO' Shows neighboring data nodes data node start phase X 4 `INFO' A data node start phase has completed been completed Node has been 3 `INFO' Displays the node, managing successfully included node, and dynamic ID into the cluster data node start phases 1 `INFO' NDB Cluster nodes starting initiated data node all start 1 `INFO' NDB Cluster nodes started phases completed data node shutdown 1 `INFO' Shutdown of data node has initiated commenced data node shutdown 1 `INFO' Unable to shut down data node aborted normally *`NODERESTART' Events* The following events are generated when restarting a node and relate to the success or failure of the node restart process. Event PrioritySeverityDescription Level Node failure phase 8 `ALERT' Reports completion of node completed failure phases Node has failed, node 8 `ALERT' Reports that a node has failed state was X Report arbitrator results 2 `ALERT' There are eight different possible results for arbitration attempts: * Arbitration check failed--less than 1/2 nodes left * Arbitration check succeeded--node group majority * Arbitration check failed--missing node group * Network partitioning--arbitration required * Arbitration succeeded--affirmative response from node X * Arbitration failed - negative response from node X * Network partitioning - no arbitrator available * Network partitioning - no arbitrator configured Completed copying a 10 `INFO' fragment Completed copying of 8 `INFO' dictionary information Completed copying 8 `INFO' distribution information Starting to copy 8 `INFO' fragments Completed copying all 8 `INFO' fragments GCP takeover started 7 `INFO' GCP takeover completed 7 `INFO' LCP takeover started 7 `INFO' LCP takeover completed 7 `INFO' (state = X) Report whether an 6 `INFO' There are seven different arbitrator is found or possible outcomes when seeking not an arbitrator: * Management server restarts arbitration thread [state=X] * Prepare arbitrator node X [ticket=Y] * Receive arbitrator node X [ticket=Y] * Started arbitrator node X [ticket=Y] * Lost arbitrator node X - process failure [state=Y] * Lost arbitrator node X - process exit [state=Y] * Lost arbitrator node X [state=Y] *`STATISTICS' Events* The following events are of a statistical nature. They provide information such as numbers of transactions and other operations, amount of data sent or received by individual nodes, and memory usage. Event PrioritySeverityDescription Level Report job scheduling 9 `INFO' Mean internal job scheduling statistics statistics Sent number of bytes 9 `INFO' Mean number of bytes sent to node X Received # of bytes 9 `INFO' Mean number of bytes received from node X Report transaction 8 `INFO' Numbers of: transactions, statistics commits, reads, simple reads, writes, concurrent operations, attribute information, and aborts Report operations 8 `INFO' Number of operations Report table create 7 `INFO' Memory usage 5 `INFO' Data and index memory usage (80%, 90%, and 100%) *`ERROR' Events* These events relate to Cluster errors and warnings. The presence of one or more of these generally indicates that a major malfunction or failure has occurred. Event PrioritySeverityDescription Dead due to missed 8 `ALERT' Node X declared `dead' due to heartbeat missed heartbeat Transporter errors 2 ERROR Transporter warnings 8 `WARNING' Missed heartbeats 8 `WARNING'Node X missed heartbeat #Y General warning events 2 `WARNING' *`INFO' Events* These events provide general information about the state of the cluster and activities associated with Cluster maintenance, such as logging and heartbeat transmission. Event PrioritySeverityDescription Sent heartbeat 12 `INFO' Heartbeat sent to node X Create log bytes 11 `INFO' Log part, log file, MB General information 2 `INFO' events  File: manual.info, Node: mysql-cluster-log-statistics, Prev: mysql-cluster-log-events, Up: mysql-cluster-event-reports 17.5.5.3 Using `CLUSTERLOG STATISTICS' in the MySQL Cluster Management Client ............................................................................. The *Note `NDB': mysql-cluster. management client's `CLUSTERLOG STATISTICS' command can provide a number of useful statistics in its output. Counters providing information about the state of the cluster are updated at 5-second reporting intervals by the transaction coordinator (TC) and the local query handler (LQH), and written to the cluster log. Transaction coordinator statistics Each transaction has one transaction coordinator, which is chosen by one of the following methods: * In a round-robin fashion * By communication proximity * (_Beginning with MySQL Cluster NDB 6.3.4_:) By supplying a data placement hint when the transaction is started *Note*: You can determine which TC selection method is used for transactions started from a given SQL node using the `ndb_optimized_node_selection' system variable. All operations within the same transaction use the same transaction coordinator, which reports the following statistics: * `Trans count' This is the number transactions started in the last interval using this TC as the transaction coordinator. Any of these transactions may have committed, have been aborted, or remain uncommitted at the end of the reporting interval. *Note*: Transactions do not migrate between TCs. * `Commit count' This is the number of transactions using this TC as the transaction coordinator that were committed in the last reporting interval. Because some transactions committed in this reporting interval may have started in a previous reporting interval, it is possible for `Commit count' to be greater than `Trans count'. * `Read count' This is the number of primary key read operations using this TC as the transaction coordinator that were started in the last reporting interval, including simple reads. This count also includes reads performed as part of unique index operations. A unique index read operation generates 2 primary key read operations--1 for the hidden unique index table, and 1 for the table on which the read takes place. * `Simple read count' This is the number of simple read operations using this TC as the transaction coordinator that were started in the last reporting interval. This is a subset of `Read count'. Because the value of `Simple read count' is incremented at a different point in time from `Read count', it can lag behind `Read count' slightly, so it is conceivable that `Simple read count' is not equal to `Read count' for a given reporting interval, even if all reads made during that time were in fact simple reads. * `Write count' This is the number of primary key write operations using this TC as the transaction coordinator that were started in the last reporting interval. This includes all inserts, updates, writes and deletes, as well as writes performed as part of unique index operations. *Note*: A unique index update operation can generate multiple PK read and write operations on the index table and on the base table. * `AttrInfoCount' This is the number of 32-bit data words received in the last reporting interval for primary key operations using this TC as the transaction coordinator. For reads, this is proportional to the number of columns requested. For inserts and updates, this is proportional to the number of columns written, and the size of their data. For delete operations, this is usually zero. Unique index operations generate multiple PK operations and so increase this count. However, data words sent to describe the PK operation itself, and the key information sent, are _not_ counted here. Attribute information sent to describe columns to read for scans, or to describe ScanFilters, is also not counted in `AttrInfoCount'. * `Concurrent Operations' This is the number of primary key or scan operations using this TC as the transaction coordinator that were started during the last reporting interval but that were not completed. Operations increment this counter when they are started and decrement it when they are completed; this occurs after the transaction commits. Dirty reads and writes--as well as failed operations--decrement this counter. The maximum value that `Concurrent Operations' can have is the maximum number of operations that a TC block can support; currently, this is `(2 * MaxNoOfConcurrentOperations) + 16 + MaxNoOfConcurrentTransactions'. (For more information about these configuration parameters, see the `Transaction Parameters' section of *Note mysql-cluster-ndbd-definition::.) * `Abort count' This is the number of transactions using this TC as the transaction coordinator that were aborted during the last reporting interval. Because some transactions that were aborted in the last reporting interval may have started in a previous reporting interval, `Abort count' can sometimes be greater than `Trans count'. * `Scans' This is the number of table scans using this TC as the transaction coordinator that were started during the last reporting interval. This does not include range scans (that is, ordered index scans). * `Range scans' This is the number of ordered index scans using this TC as the transaction coordinator that were started in the last reporting interval. Local query handler statistics (`Operations') There is 1 cluster event per local query handler block (that is, 1 per data node process). Operations are recorded in the LQH where the data they are operating on resides. *Note*: A single transaction may operate on data stored in multiple LQH blocks. The `Operations' statistic provides the number of local operations performed by this LQH block in the last reporting interval, and includes all types of read and write operations (insert, update, write, and delete operations). This also includes operations used to replicate writes. For example, in a 2-replica cluster, the write to the primary replica is recorded in the primary LQH, and the write to the backup will be recorded in the backup LQH. Unique key operations may result in multiple local operations; however, this does _not_ include local operations generated as a result of a table scan or ordered index scan, which are not counted. Process scheduler statistics In addition to the statistics reported by the transaction coordinator and local query handler, each *Note `ndbd': mysql-cluster-programs-ndbd. process has a scheduler which also provides useful metrics relating to the performance of a MySQL Cluster. This scheduler runs in an infinite loop; during each loop the scheduler performs the following tasks: 1. Read any incoming messages from sockets into a job buffer. 2. Check whether there are any timed messages to be executed; if so, put these into the job buffer as well. 3. Execute (in a loop) any messages in the job buffer. 4. Send any distributed messages that were generated by executing the messages in the job buffer. 5. Wait for any new incoming messages. Process scheduler statistics include the following: * `Mean Loop Counter' This is the number of loops executed in the third step from the preceding list. This statistic increases in size as the utilization of the TCP/IP buffer improves. You can use this to monitor changes in performance as you add new data node processes. * `Mean send size' and `Mean receive size' These statistics enable you to gauge the efficiency of, respectively writes and reads between nodes. The values are given in bytes. Higher values mean a lower cost per byte sent or received; the maximum value is 64K. To cause all cluster log statistics to be logged, you can use the following command in the *Note `NDB': mysql-cluster. management client: ndb_mgm> ALL CLUSTERLOG STATISTICS=15 *Note*: Setting the threshold for `STATISTICS' to 15 causes the cluster log to become very verbose, and to grow quite rapidly in size, in direct proportion to the number of cluster nodes and the amount of activity in the MySQL Cluster. For more information about MySQL Cluster management client commands relating to logging and reporting, see *Note mysql-cluster-logging-management-commands::.  File: manual.info, Node: mysql-cluster-logs-ndb-messages, Next: mysql-cluster-single-user-mode, Prev: mysql-cluster-event-reports, Up: mysql-cluster-management 17.5.6 MySQL Cluster Log Messages --------------------------------- * Menu: * mysql-cluster-logs-cluster-log:: MySQL Cluster: Messages in the Cluster Log * mysql-cluster-ndb-transporter-errors:: MySQL Cluster: `NDB' Transporter Errors This section contains information about the messages written to the cluster log in response to different cluster log events. It provides additional, more specific information on *Note `NDB': mysql-cluster. transporter errors.  File: manual.info, Node: mysql-cluster-logs-cluster-log, Next: mysql-cluster-ndb-transporter-errors, Prev: mysql-cluster-logs-ndb-messages, Up: mysql-cluster-logs-ndb-messages 17.5.6.1 MySQL Cluster: Messages in the Cluster Log ................................................... The following table lists the most common *Note `NDB': mysql-cluster. cluster log messages. For information about the cluster log, log events, and event types, see *Note mysql-cluster-event-reports::. These log messages also correspond to log event types in the MGM API; see The `Ndb_logevent_type' Type (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-logevent-type.html), for related information of interest to Cluster API developers. Log Message Event Name `Node MGM_NODE_ID: Node DATA_NODE_ID `Connected' Connected' Event Type Description `Connection' The data node having node ID NODE_ID has connected to the management server (node Priority MGM_NODE_ID). 8 Severity `INFO' Log Message Event Name `Node MGM_NODE_ID: Node DATA_NODE_ID `Disconnected' Disconnected' Event Type Description `Connection' The data node having node ID DATA_NODE_ID has disconnected from the management Priority server (node MGM_NODE_ID). 8 Severity `ALERT' Log Message Event Name `Node DATA_NODE_ID: Communication to Node `CommunicationClosed' API_NODE_ID closed' Event Type Description `Connection' The API node or SQL node having node ID API_NODE_ID is no longer communicating Priority with data node DATA_NODE_ID. 8 Severity `INFO' Log Message Event Name `Node DATA_NODE_ID: Communication to Node `CommunicationOpened' API_NODE_ID opened' Event Type Description `Connection' The API node or SQL node having node ID API_NODE_ID is now communicating with data Priority node DATA_NODE_ID. 8 Severity `INFO' Log Message Event Name `Node MGM_NODE_ID: Node API_NODE_ID: API `ConnectedApiVersion' VERSION' Event Type Description `Connection' The API node having node ID API_NODE_ID has connected to management node Priority MGM_NODE_ID using *Note `NDB': mysql-cluster. API version VERSION 8 (generally the same as the MySQL version number). Severity `INFO' Log Message Event Name `Node NODE_ID: Global checkpoint GCI `GlobalCheckpointStarted' started' Event Type Description `Checkpoint' A global checkpoint with the ID GCI has been started; node NODE_ID is the master Priority responsible for this global checkpoint. 9 Severity `INFO' Log Message Event Name `Node NODE_ID: Global checkpoint GCI `GlobalCheckpointCompleted' completed' Event Type Description `Checkpoint' The global checkpoint having the ID GCI has been completed; node NODE_ID was the Priority master responsible for this global checkpoint. 10 Severity `INFO' Log Message Event Name `Node NODE_ID: Local checkpoint LCP `LocalCheckpointStarted' started. Keep GCI = CURRENT_GCI oldest restorable GCI = OLD_GCI' Event Type Description `Checkpoint' The local checkpoint having sequence ID Priority LCP has been started on node NODE_ID. The most recent GCI that can be used has the 7 index CURRENT_GCI, and the oldest GCI from which the cluster can be restored has the Severity index OLD_GCI. `INFO' Log Message Event Name `Node NODE_ID: Local checkpoint LCP `LocalCheckpointCompleted' completed' Event Type Description `Checkpoint' The local checkpoint having sequence ID LCP on node NODE_ID has been completed. Priority 8 Severity `INFO' Log Message Event Name `Node NODE_ID: Local Checkpoint stopped in `LCPStoppedInCalcKeepGci' CALCULATED_KEEP_GCI' Event Type Description `Checkpoint' The node was unable to determine the most recent usable GCI. Priority 0 Severity `ALERT' Log Message Event Name `Node NODE_ID: Table ID = TABLE_ID, `LCPFragmentCompleted' fragment ID = FRAGMENT_ID has completed LCP on Node NODE_ID maxGciStarted: Event Type STARTED_GCI maxGciCompleted: COMPLETED_GCI' `Checkpoint' Description Priority A table fragment has been checkpointed to disk on node NODE_ID. The GCI in progress 11 has the index STARTED_GCI, and the most recent GCI to have been completed has the Severity index COMPLETED_GCI. `INFO' Log Message Event Name `Node NODE_ID: ACC Blocked NUM_1 and TUP `UndoLogBlocked' Blocked NUM_2 times last second' Event Type Description `Checkpoint' Undo logging is blocked because the log buffer is close to overflowing. Priority 7 Severity `INFO' Log Message Event Name `Node NODE_ID: Start initiated VERSION' `NDBStartStarted' Description Event Type Data node NODE_ID, running *Note `NDB': `StartUp' mysql-cluster. version VERSION, is beginning its startup process. Priority 1 Severity `INFO' Log Message Event Name `Node NODE_ID: Started VERSION' `NDBStartCompleted' Description Event Type Data node NODE_ID, running *Note `NDB': `StartUp' mysql-cluster. version VERSION, has started successfully. Priority 1 Severity `INFO' Log Message Event Name `Node NODE_ID: STTORRY received after `STTORRYRecieved' restart finished' Event Type Description `StartUp' The node has received a signal indicating that a cluster restart has completed. Priority 15 Severity `INFO' Log Message Event Name `Node NODE_ID: Start phase PHASE completed `StartPhaseCompleted' (TYPE)' Event Type Description `StartUp' The node has completed start phase PHASE of a TYPE start. For a listing of start Priority phases, see *Note mysql-cluster-start-phases::. (TYPE is 4 one of `initial', `system', `node', `initial node', or `'.) Severity `INFO' Log Message Event Name `Node NODE_ID: CM_REGCONF president = `CM_REGCONF' PRESIDENT_ID, own Node = OWN_ID, our dynamic id = DYNAMIC_ID' Event Type Description `StartUp' Node PRESIDENT_ID has been selected as Priority `president'. OWN_ID and DYNAMIC_ID should always be the same as the ID (NODE_ID) of 3 the reporting node. Severity `INFO' Log Message Event Name `Node NODE_ID: CM_REGREF from Node `CM_REGREF' PRESIDENT_ID to our Node NODE_ID. Cause = CAUSE' Event Type Description `StartUp' The reporting node (ID NODE_ID) was unable Priority to accept node PRESIDENT_ID as president. The CAUSE of the problem is given as one of 8 `Busy', `Election with wait = false', `Not president', `Election without selecting new Severity candidate', or `No such cause'. `INFO' Log Message Event Name `Node NODE_ID: We are Node OWN_ID with `FIND_NEIGHBOURS' dynamic ID DYNAMIC_ID, our left neighbour is Node ID_1, our right is Node ID_2' Event Type Description `StartUp' The node has discovered its neighboring Priority nodes in the cluster (node ID_1 and node ID_2). NODE_ID, OWN_ID, and DYNAMIC_ID 8 should always be the same; if they are not, this indicates a serious Severity misconfiguration of the cluster nodes. `INFO' Log Message Event Name `Node NODE_ID: TYPE shutdown initiated' `NDBStopStarted' Description Event Type The node has received a shutdown signal. `StartUp' The TYPE of shutdown is either `Cluster' or `Node'. Priority 1 Severity `INFO' Log Message Event Name `Node NODE_ID: Node shutdown completed '[`, `NDBStopCompleted' ACTION'] [`Initiated by signal SIGNAL.'] Event Type Description `StartUp' The node has been shut down. This report may include an ACTION, which if present is Priority one of `restarting', `no start', or `initial'. The report may also include a 1 reference to an *Note `NDB': mysql-cluster. Protocol SIGNAL; for Severity possible signals, refer to Operations and Signals `INFO' (http://dev.mysql.com/doc/ndbapi/en/ndb-internals-ndb-protocol-operations-signals.html). Log Message Event Name `Node NODE_ID: Forced node shutdown `NDBStopForced' completed '[`, action']`.' [`Occured during startphase START_PHASE.'] [` Event Type Initiated by SIGNAL.'] [`Caused by error ERROR_CODE: `StartUp' 'ERROR_MESSAGE(ERROR_CLASSIFICATION). ERROR_STATUS'.' [`(extra info Priority EXTRA_CODE)']] 1 Description Severity The node has been forcibly shut down. The ACTION (one of `restarting', `no start', `ALERT' or `initial') subsequently being taken, if any, is also reported. If the shutdown occurred while the node was starting, the report includes the START_PHASE during which the node failed. If this was a result of a SIGNAL sent to the node, this information is also provided (see Operations and Signals (http://dev.mysql.com/doc/ndbapi/en/ndb-internals-ndb-protocol-operations-signals.html), for more information). If the error causing the failure is known, this is also included; for more information about *Note `NDB': mysql-cluster. error messages and classifications, see MySQL Cluster API Errors (http://dev.mysql.com/doc/ndbapi/en/ndb-errors.html). Log Message Event Name `Node NODE_ID: Node shutdown aborted' `NDBStopAborted' Description Event Type The node shutdown process was aborted by `StartUp' the user. Priority 1 Severity `INFO' Log Message Event Name `Node NODE_ID: StartLog: [GCI Keep: `StartREDOLog' KEEP_POS LastCompleted: LAST_POS NewestRestorable: RESTORE_POS]' Event Type Description `StartUp' This reports global checkpoints referenced Priority during a node start. The redo log prior to KEEP_POS is dropped. LAST_POS is the last 4 global checkpoint in which data node the participated; RESTORE_POS is the global Severity checkpoint which is actually used to restore all data nodes. `INFO' Log Message Event Name STARTUP_MESSAGE [_Listed separately; see `StartReport' below._] Event Type Description `StartUp' There are a number of possible startup messages that can be logged under Priority different circumstances. 4 Severity `INFO' Log Message Event Name `Node NODE_ID: Node restart completed copy `NR_CopyDict' of dictionary information' Event Type Description `NodeRestart' Copying of data dictionary information to the restarted node has been completed. Priority 8 Severity `INFO' Log Message Event Name `Node NODE_ID: Node restart completed copy `NR_CopyDistr' of distribution information' Event Type Description `NodeRestart' Copying of data distribution information to the restarted node has been completed. Priority 8 Severity `INFO' Log Message Event Name `Node NODE_ID: Node restart starting to `NR_CopyFragsStarted' copy the fragments to Node NODE_ID' Event Type Description `NodeRestart' Copy of fragments to starting data node NODE_ID has begun Priority 8 Severity `INFO' Log Message Event Name `Node NODE_ID: Table ID = TABLE_ID, `NR_CopyFragDone' fragment ID = FRAGMENT_ID have been copied to Node NODE_ID' Event Type Description `NodeRestart' Fragment FRAGMENT_ID from table TABLE_ID Priority has been copied to data node NODE_ID 10 Severity `INFO' Log Message Event Name `Node NODE_ID: Node restart completed `NR_CopyFragsCompleted' copying the fragments to Node NODE_ID' Event Type Description `NodeRestart' Copying of all table fragments to restarting data node NODE_ID has been Priority completed 8 Severity `INFO' Log Message Event Name Any of the following: `NodeFailCompleted' 1. `Node NODE_ID: Node NODE1_ID completed Event Type failure of Node NODE2_ID' `NodeRestart' 2. `All nodes completed failure of Node NODE_ID' Priority 3. `Node failure of NODE_IDBLOCK 8 completed' Description Severity One of the following (each corresponding `ALERT' to the same-numbered message listed above): 1. Data node NODE1_ID has detected the failure of data node NODE2_ID 2. All (remaining) data nodes have detected the failure of data node NODE_ID 3. The failure of data node NODE_ID has been detected in the BLOCK*Note `NDB': mysql-cluster. kernel block, where block is 1 of `DBTC', `DBDICT', `DBDIH', or `DBLQH'; for more information, see `NDB' Kernel Blocks (http://dev.mysql.com/doc/ndbapi/en/ndb-internals-kernel-blocks.html) Log Message Event Name `Node MGM_NODE_ID: Node DATA_NODE_ID has `NODE_FAILREP' failed. The Node state at failure was STATE_CODE' Event Type Description `NodeRestart' A data node has failed. Its state at the Priority time of failure is described by an arbitration state code STATE_CODE: possible 8 state code values can be found in the file `include/kernel/signaldata/ArbitSignalData.hpp'.Severity `ALERT' Log Message Event Name `President restarts arbitration thread `ArbitState' [state=STATE_CODE]' or `Prepare arbitrator node NODE_ID [ticket=TICKET_ID]' or Event Type `Receive arbitrator node NODE_ID [ticket=TICKET_ID]' or `Started arbitrator `NodeRestart' node NODE_ID [ticket=TICKET_ID]' or `Lost arbitrator node NODE_ID - process failure Priority [state=STATE_CODE]' or `Lost arbitrator node NODE_ID - process exit 6 [state=STATE_CODE]' or `Lost arbitrator node NODE_ID - ERROR_MESSAGE Severity [state=STATE_CODE]' `INFO' Description This is a report on the current state and progress of arbitration in the cluster. NODE_ID is the node ID of the management node or SQL node selected as the arbitrator. STATE_CODE is an arbitration state code, as found in `include/kernel/signaldata/ArbitSignalData.hpp'. When an error has occurred, an ERROR_MESSAGE, also defined in `ArbitSignalData.hpp', is provided. TICKET_ID is a unique identifier handed out by the arbitrator when it is selected to all the nodes that participated in its selection; this is used to ensure that each node requesting arbitration was one of the nodes that took part in the selection process. Log Message Event Name `Arbitration check lost - less than 1/2 `ArbitResult' nodes left' or `Arbitration check won - all node groups and more than 1/2 nodes Event Type left' or `Arbitration check won - node group majority' or `Arbitration check lost `NodeRestart' - missing node group' or `Network partitioning - arbitration required' or Priority `Arbitration won - positive reply from node NODE_ID' or `Arbitration lost - negative 2 reply from node NODE_ID' or `Network partitioning - no arbitrator available' or Severity `Network partitioning - no arbitrator configured' or `Arbitration failure - `ALERT' ERROR_MESSAGE [state=STATE_CODE]' Description This message reports on the result of arbitration. In the event of arbitration failure, an ERROR_MESSAGE and an arbitration STATE_CODE are provided; definitions for both of these are found in `include/kernel/signaldata/ArbitSignalData.hpp'. Log Message Event Name `Node NODE_ID: GCP Take over started' `GCP_TakeoverStarted' Description Event Type This node is attempting to assume `NodeRestart' responsibility for the next global checkpoint (that is, it is becoming the Priority master node) 7 Severity `INFO' Log Message Event Name `Node NODE_ID: GCP Take over completed' `GCP_TakeoverCompleted' Description Event Type This node has become the master, and has `NodeRestart' assumed responsibility for the next global checkpoint Priority 7 Severity `INFO' Log Message Event Name `Node NODE_ID: LCP Take over started' `LCP_TakeoverStarted' Description Event Type This node is attempting to assume `NodeRestart' responsibility for the next set of local checkpoints (that is, it is becoming the Priority master node) 7 Severity `INFO' Log Message Event Name `Node NODE_ID: LCP Take over completed' `LCP_TakeoverCompleted' Description Event Type This node has become the master, and has `NodeRestart' assumed responsibility for the next set of local checkpoints Priority 7 Severity `INFO' Log Message Event Name `Node NODE_ID: Trans. Count = `TransReportCounters' TRANSACTIONS, Commit Count = COMMITS, Read Count = READS, Simple Read Count = Event Type SIMPLE_READS, Write Count = WRITES, AttrInfo Count = ATTRINFO_OBJECTS, `Statistic' Concurrent Operations = CONCURRENT_OPERATIONS, Abort Count = Priority ABORTS, Scans = SCANS, Range scans = RANGE_SCANS' 8 Description Severity This report of transaction activity is `INFO' given approximately once every 10 seconds Log Message Event Name `Node NODE_ID: Operations=OPERATIONS' `OperationReportCounters' Description Event Type Number of operations performed by this `Statistic' node, provided approximately once every 10 seconds Priority 8 Severity `INFO' Log Message Event Name `Node NODE_ID: Table with ID = TABLE_ID `TableCreated' created' Event Type Description `Statistic' A table having the table ID shown has been created Priority 7 Severity `INFO' Log Message Event Name `Node NODE_ID: Mean loop Counter in doJob `JobStatistic' last 8192 times = COUNT' Event Type Description `Statistic' Priority 9 Severity `INFO' Log Message Event Name `Mean send size to Node = NODE_ID last `SendBytesStatistic' 4096 sends = BYTES bytes' Event Type Description `Statistic' This node is sending an average of BYTES bytes per send to node NODE_ID Priority 9 Severity `INFO' Log Message Event Name `Mean receive size to Node = NODE_ID last `ReceiveBytesStatistic' 4096 sends = BYTES bytes' Event Type Description `Statistic' This node is receiving an average of BYTES of data each time it receives data from Priority node NODE_ID 9 Severity `INFO' Log Message Event Name `Node NODE_ID: Data usage is `MemoryUsage' DATA_MEMORY_PERCENTAGE% (DATA_PAGES_USED 32K pages of total DATA_PAGES_TOTAL)' / Event Type `Node NODE_ID: Index usage is INDEX_MEMORY_PERCENTAGE% (INDEX_PAGES_USED `Statistic' 8K pages of total INDEX_PAGES_TOTAL) ' Priority Description 5 This report is generated when a `DUMP 1000' command is issued in the cluster Severity management client; for more information, see `DUMP 1000' `INFO' (http://dev.mysql.com/doc/ndbapi/en/ndb-internals-dump-command-1000.html), in MySQL Cluster Internals (http://dev.mysql.com/doc/ndbapi/en/ndb-internals.html) Log Message Event Name `Node NODE1_ID: Transporter to node `TransporterError' NODE2_ID reported error ERROR_CODE: ERROR_MESSAGE' Event Type Description `Error' A transporter error occurred while Priority communicating with node NODE2_ID; for a listing of transporter error codes and 2 messages, see `NDB' Transporter Errors (http://dev.mysql.com/doc/ndbapi/en/ndb-transporter-errors.html),Severity in MySQL Cluster Internals (http://dev.mysql.com/doc/ndbapi/en/ndb-internals.html)`ERROR' Log Message Event Name `Node NODE1_ID: Transporter to node `TransporterWarning' NODE2_ID reported error ERROR_CODE: ERROR_MESSAGE' Event Type Description `Error' A warning of a potential transporter Priority problem while communicating with node NODE2_ID; for a listing of transporter 8 error codes and messages, see `NDB' Transporter Errors Severity (http://dev.mysql.com/doc/ndbapi/en/ndb-transporter-errors.html), for more information `WARNING' Log Message Event Name `Node NODE1_ID: Node NODE2_ID missed `MissedHeartbeat' heartbeat HEARTBEAT_ID' Event Type Description `Error' This node missed a heartbeat from node NODE2_ID Priority 8 Severity `WARNING' Log Message Event Name `Node NODE1_ID: Node NODE2_ID declared `DeadDueToHeartbeat' dead due to missed heartbeat' Event Type Description `Error' This node has missed at least 3 heartbeats from node NODE2_ID, and so has declared Priority that node `dead' 8 Severity `ALERT' Log Message Event Name `Node NODE1_ID: Node Sent Heartbeat to `SentHeartbeat' node = NODE2_ID' Event Type Description `Info' This node has sent a heartbeat to node NODE2_ID Priority 12 Severity `INFO' Log Message Event Name `Node NODE_ID: Event buffer status: `EventBufferStatus' used=BYTES_USED (PERCENT_USED%) alloc=BYTES_ALLOCATED (PERCENT_AVAILABLE%) Event Type max=BYTES_AVAILABLE apply_gci=LATEST_RESTORABLE_GCI `Info' latest_gci=LATEST_GCI' Priority Description 7 This report is seen during heavy event buffer usage, for example, when many Severity updates are being applied in a relatively short period of time; the report shows the `INFO' number of bytes and the percentage of event buffer memory used, the bytes allocated and percentage still available, and the latest and latest restorable global checkpoints Log Message Event Name `Node NODE_ID: Entering single user mode', `SingleUser' `Node NODE_ID: Entered single user mode Node API_NODE_ID has exclusive access', Event Type `Node NODE_ID: Entering single user mode' `Info' Description Priority These reports are written to the cluster log when entering and exiting single user 7 mode; API_NODE_ID is the node ID of the API or SQL having exclusive access to the Severity cluster (for more information, see *Note mysql-cluster-single-user-mode::); the `INFO' message `Unknown single user report API_NODE_ID' indicates an error has taken place and should never be seen in normal operation Log Message Event Name `Node NODE_ID: Backup BACKUP_ID started `BackupStarted' from node MGM_NODE_ID' Event Type Description `Backup' A backup has been started using the management node having MGM_NODE_ID; this Priority message is also displayed in the cluster management client when the `START BACKUP' 7 command is issued; for more information, see *Note Severity mysql-cluster-backup-using-management-client:: `INFO' Log Message Event Name `Node NODE_ID: Backup BACKUP_ID started `BackupCompleted' from node MGM_NODE_ID completed. StartGCP: START_GCP StopGCP: STOP_GCP #Records: Event Type RECORDS #LogRecords: LOG_RECORDS Data: DATA_BYTES bytes Log: LOG_BYTES bytes' `Backup' Description Priority The backup having the ID BACKUP_ID has been 7 completed; for more information, see *Note mysql-cluster-backup-using-management-client::Severity `INFO' Log Message Event Name `Node NODE_ID: Backup request from `BackupFailedToStart' MGM_NODE_ID failed to start. Error: ERROR_CODE' Event Type Description `Backup' The backup failed to start; for error Priority codes, see MGM`' API Errors (http://dev.mysql.com/doc/ndbapi/en/mgm-errors.html)7 Severity `ALERT' Log Message Event Name `Node NODE_ID: Backup BACKUP_ID started `BackupAborted' from MGM_NODE_ID has been aborted. Error: ERROR_CODE' Event Type Description `Backup' The backup was terminated after starting, Priority possibly due to user intervention 7 Severity `ALERT'  File: manual.info, Node: mysql-cluster-ndb-transporter-errors, Prev: mysql-cluster-logs-cluster-log, Up: mysql-cluster-logs-ndb-messages 17.5.6.2 MySQL Cluster: `NDB' Transporter Errors ................................................ This section lists error codes, names, and messages that are written to the cluster log in the event of transporter errors. Error Error Name Error Text Code 0x00 TE_NO_ERROR `No error' 0x01 TE_ERROR_CLOSING_SOCKET `Error found during closing of socket' 0x02 TE_ERROR_IN_SELECT_BEFORE_ACCEPT `Error found before accept. The transporter will retry' 0x03 TE_INVALID_MESSAGE_LENGTH `Error found in message (invalid message length)' 0x04 TE_INVALID_CHECKSUM `Error found in message (checksum)' 0x05 TE_COULD_NOT_CREATE_SOCKET `Error found while creating socket(can't create socket)' 0x06 TE_COULD_NOT_BIND_SOCKET `Error found while binding server socket' 0x07 TE_LISTEN_FAILED `Error found while listening to server socket' 0x08 TE_ACCEPT_RETURN_ERROR `Error found during accept(accept return error)' 0x0b TE_SHM_DISCONNECT `The remote node has disconnected' 0x0c TE_SHM_IPC_STAT `Unable to check shm segment' 0x0d TE_SHM_UNABLE_TO_CREATE_SEGMENT `Unable to create shm segment' 0x0e TE_SHM_UNABLE_TO_ATTACH_SEGMENT `Unable to attach shm segment' 0x0f TE_SHM_UNABLE_TO_REMOVE_SEGMENT `Unable to remove shm segment' 0x10 TE_TOO_SMALL_SIGID `Sig ID too small' 0x11 TE_TOO_LARGE_SIGID `Sig ID too large' 0x12 TE_WAIT_STACK_FULL `Wait stack was full' 0x13 TE_RECEIVE_BUFFER_FULL `Receive buffer was full' 0x14 TE_SIGNAL_LOST_SEND_BUFFER_FULL `Send buffer was full,and trying to force send fails' 0x15 TE_SIGNAL_LOST `Send failed for unknown reason(signal lost)' 0x16 TE_SEND_BUFFER_FULL `The send buffer was full, but sleeping for a while solved' 0x0017 TE_SCI_LINK_ERROR `There is no link from this node to the switch' 0x18 TE_SCI_UNABLE_TO_START_SEQUENCE `Could not start a sequence, because system resources are exumed or no sequence has been created' 0x19 TE_SCI_UNABLE_TO_REMOVE_SEQUENCE `Could not remove a sequence' 0x1a TE_SCI_UNABLE_TO_CREATE_SEQUENCE `Could not create a sequence, because system resources are exempted. Must reboot' 0x1b TE_SCI_UNRECOVERABLE_DATA_TFX_ERROR `Tried to send data on redundant link but failed' 0x1c TE_SCI_CANNOT_INIT_LOCALSEGMENT `Cannot initialize local segment' 0x1d TE_SCI_CANNOT_MAP_REMOTESEGMENT `Cannot map remote segment' 0x1e TE_SCI_UNABLE_TO_UNMAP_SEGMENT `Cannot free the resources used by this segment (step 1)' 0x1f TE_SCI_UNABLE_TO_REMOVE_SEGMENT `Cannot free the resources used by this segment (step 2)' 0x20 TE_SCI_UNABLE_TO_DISCONNECT_SEGMENT `Cannot disconnect from a remote segment' 0x21 TE_SHM_IPC_PERMANENT `Shm ipc Permanent error' 0x22 TE_SCI_UNABLE_TO_CLOSE_CHANNEL `Unable to close the sci channel and the resources allocated'  File: manual.info, Node: mysql-cluster-single-user-mode, Next: mysql-cluster-sql-statements, Prev: mysql-cluster-logs-ndb-messages, Up: mysql-cluster-management 17.5.7 MySQL Cluster Single User Mode ------------------------------------- _Single user mode_ enables the database administrator to restrict access to the database system to a single API node, such as a MySQL server (SQL node) or an instance of *Note `ndb_restore': mysql-cluster-programs-ndb-restore. When entering single user mode, connections to all other API nodes are closed gracefully and all running transactions are aborted. No new transactions are permitted to start. Once the cluster has entered single user mode, only the designated API node is granted access to the database. You can use the `ALL STATUS' command in the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client to see when the cluster has entered single user mode. Beginning with MySQL Cluster NDB 7.1.1, you can also check the `status' column of the *Note `ndbinfo.nodes': mysql-cluster-ndbinfo-nodes. table (see *Note mysql-cluster-ndbinfo-nodes::, for more information). Example: ndb_mgm> ENTER SINGLE USER MODE 5 After this command has executed and the cluster has entered single user mode, the API node whose node ID is `5' becomes the cluster's only permitted user. The node specified in the preceding command must be an API node; attempting to specify any other type of node will be rejected. *Note*: When the preceding command is invoked, all transactions running on the designated node are aborted, the connection is closed, and the server must be restarted. The command `EXIT SINGLE USER MODE' changes the state of the cluster's data nodes from single user mode to normal mode. API nodes--such as MySQL Servers--waiting for a connection (that is, waiting for the cluster to become ready and available), are again permitted to connect. The API node denoted as the single-user node continues to run (if still connected) during and after the state change. Example: ndb_mgm> EXIT SINGLE USER MODE There are two recommended ways to handle a node failure when running in single user mode: * Method 1: 1. Finish all single user mode transactions 2. Issue the `EXIT SINGLE USER MODE' command 3. Restart the cluster's data nodes * Method 2: Restart database nodes prior to entering single user mode.  File: manual.info, Node: mysql-cluster-sql-statements, Next: mysql-cluster-ndbinfo, Prev: mysql-cluster-single-user-mode, Up: mysql-cluster-management 17.5.8 Quick Reference: MySQL Cluster SQL Statements ---------------------------------------------------- This section discusses several SQL statements that can prove useful in managing and monitoring a MySQL server that is connected to a MySQL Cluster, and in some cases provide information about the cluster itself. * *Note `SHOW ENGINE NDB STATUS': show-engine, *Note `SHOW ENGINE NDBCLUSTER STATUS': show-engine. The output of this statement contains information about the server's connection to the cluster, creation and usage of MySQL Cluster objects, and binary logging for MySQL Cluster replication. See *Note show-engine::, for a usage example and more detailed information. * *Note `SHOW ENGINES': show-engines. This statement can be used to determine whether or not clustering support is enabled in the MySQL server, and if so, whether it is active. See *Note show-engines::, for more detailed information. *Note*: In MySQL 5.1 and later, this statement does not support a `LIKE' clause. However, you can use `LIKE' to filter queries against the *Note `INFORMATION_SCHEMA.ENGINES': engines-table, as discussed in the next item. * `SELECT * FROM INFORMATION_SCHEMA.ENGINES [WHERE ENGINE LIKE 'NDB%']' This is the equivalent of *Note `SHOW ENGINES': show-engines, but uses the *Note `ENGINES': engines-table. table of the `INFORMATION_SCHEMA' database (available beginning with MySQL 5.1.5). Unlike the case with the *Note `SHOW ENGINES': show-engines. statement, it is possible to filter the results using a `LIKE' clause, and to select specific columns to obtain information that may be of use in scripts. For example, the following query shows whether the server was built with *Note `NDB': mysql-cluster. support and, if so, whether it is enabled: mysql> SELECT SUPPORT FROM INFORMATION_SCHEMA.ENGINES -> WHERE ENGINE LIKE 'NDB%'; +---------+ | support | +---------+ | ENABLED | +---------+ See *Note engines-table::, for more information. * `SHOW VARIABLES LIKE 'NDB%'' This statement provides a list of most server system variables relating to the *Note `NDB': mysql-cluster. storage engine, and their values, as shown here: mysql> SHOW VARIABLES LIKE 'NDB%'; +-------------------------------------+-------+ | Variable_name | Value | +-------------------------------------+-------+ | ndb_autoincrement_prefetch_sz | 32 | | ndb_cache_check_time | 0 | | ndb_extra_logging | 0 | | ndb_force_send | ON | | ndb_index_stat_cache_entries | 32 | | ndb_index_stat_enable | OFF | | ndb_index_stat_update_freq | 20 | | ndb_report_thresh_binlog_epoch_slip | 3 | | ndb_report_thresh_binlog_mem_usage | 10 | | ndb_use_copying_alter_table | OFF | | ndb_use_exact_count | ON | | ndb_use_transactions | ON | +-------------------------------------+-------+ See *Note server-system-variables::, for more information. * `SELECT * FROM INFORMATION_SCHEMA.GLOBAL_VARIABLES WHERE VARIABLE_NAME LIKE 'NDB%';' This statement is the equivalent of the `SHOW' command described in the previous item, and provides almost identical output, as shown here: mysql> SELECT * FROM INFORMATION_SCHEMA.GLOBAL_VARIABLES -> WHERE VARIABLE_NAME LIKE 'NDB%'; +-------------------------------------+----------------+ | VARIABLE_NAME | VARIABLE_VALUE | +-------------------------------------+----------------+ | NDB_AUTOINCREMENT_PREFETCH_SZ | 32 | | NDB_CACHE_CHECK_TIME | 0 | | NDB_EXTRA_LOGGING | 0 | | NDB_FORCE_SEND | ON | | NDB_INDEX_STAT_CACHE_ENTRIES | 32 | | NDB_INDEX_STAT_ENABLE | OFF | | NDB_INDEX_STAT_UPDATE_FREQ | 20 | | NDB_REPORT_THRESH_BINLOG_EPOCH_SLIP | 3 | | NDB_REPORT_THRESH_BINLOG_MEM_USAGE | 10 | | NDB_USE_COPYING_ALTER_TABLE | OFF | | NDB_USE_EXACT_COUNT | ON | | NDB_USE_TRANSACTIONS | ON | +-------------------------------------+----------------+ Unlike the case with the `SHOW' command, it is possible to select individual columns. For example: mysql> SELECT VARIABLE_VALUE -> FROM INFORMATION_SCHEMA.GLOBAL_VARIABLES -> WHERE VARIABLE_NAME = 'ndb_force_send'; +----------------+ | VARIABLE_VALUE | +----------------+ | ON | +----------------+ See *Note variables-table::, and *Note server-system-variables::, for more information. * `SHOW STATUS LIKE 'NDB%'' This statement shows at a glance whether or not the MySQL server is acting as a cluster SQL node, and if so, it provides the MySQL server's cluster node ID, the host name and port for the cluster management server to which it is connected, and the number of data nodes in the cluster, as shown here: mysql> SHOW STATUS LIKE 'NDB%'; +--------------------------+---------------+ | Variable_name | Value | +--------------------------+---------------+ | Ndb_cluster_node_id | 10 | | Ndb_config_from_host | 192.168.0.103 | | Ndb_config_from_port | 1186 | | Ndb_number_of_data_nodes | 4 | +--------------------------+---------------+ If the MySQL server was built with clustering support, but it is not connected to a cluster, all rows in the output of this statement contain a zero or an empty string: mysql> SHOW STATUS LIKE 'NDB%'; +--------------------------+-------+ | Variable_name | Value | +--------------------------+-------+ | Ndb_cluster_node_id | 0 | | Ndb_config_from_host | | | Ndb_config_from_port | 0 | | Ndb_number_of_data_nodes | 0 | +--------------------------+-------+ See also *Note show-status::. * `SELECT * FROM INFORMATION_SCHEMA.GLOBAL_STATUS WHERE VARIABLE_NAME LIKE 'NDB%';' Beginning with MySQL 5.1.12, this statement provides similar output to the `SHOW' command discussed in the previous item. However, unlike the case with *Note `SHOW STATUS': show-status, it is possible using the *Note `SELECT': select. to extract values in SQL for use in scripts for monitoring and automation purposes. See *Note status-table::, for more information. Beginning with MySQL Cluster NDB 7.1.1, you can also query the tables in the *Note `ndbinfo': mysql-cluster-ndbinfo. information database for real-time data about many MySQL Cluster operations. See *Note mysql-cluster-ndbinfo::.  File: manual.info, Node: mysql-cluster-ndbinfo, Next: mysql-cluster-security, Prev: mysql-cluster-sql-statements, Up: mysql-cluster-management 17.5.9 The `ndbinfo' MySQL Cluster Information Database ------------------------------------------------------- * Menu: * mysql-cluster-ndbinfo-blocks:: The `ndbinfo blocks' Table * mysql-cluster-ndbinfo-config-params:: The `ndbinfo config_params' Table * mysql-cluster-ndbinfo-counters:: The `ndbinfo counters' Table * mysql-cluster-ndbinfo-diskpagebuffer:: The `ndbinfo diskpagebuffer' Table * mysql-cluster-ndbinfo-logbuffers:: The `ndbinfo logbuffers' Table * mysql-cluster-ndbinfo-logspaces:: The `ndbinfo logspaces' Table * mysql-cluster-ndbinfo-memoryusage:: The `ndbinfo memoryusage' Table * mysql-cluster-ndbinfo-nodes:: The `ndbinfo nodes' Table * mysql-cluster-ndbinfo-pools:: The `ndbinfo pools' Table * mysql-cluster-ndbinfo-resources:: The `ndbinfo resources' Table * mysql-cluster-ndbinfo-transporters:: The `ndbinfo transporters' Table `ndbinfo' is a database storing containing information specific to MySQL Cluster, available beginning with MySQL Cluster NDB 7.1.1. This database contains a number of tables, each providing a different sort of data about MySQL Cluster node status, resource usage, and operations. You can find more detailed information about each of these tables in the next several sections. `ndbinfo' is included with MySQL Cluster support in the MySQL Server; no special compilation or configuration steps are required; the tables are created by the MySQL Server when it connects to the cluster. You can verify that `ndbinfo' support is active in a given MySQL Server instance using *Note `SHOW PLUGINS': show-plugins.; if `ndbinfo' support is enabled, you should see a row containing `ndbinfo' in the `Name' column and `ACTIVE' in the `Status' column, as shown here (emphasized text): mysql> SHOW PLUGINS; +------------+----------+----------------+---------+---------+ | Name | Status | Type | Library | License | +------------+----------+----------------+---------+---------+ | binlog | ACTIVE | STORAGE ENGINE | NULL | GPL | | partition | ACTIVE | STORAGE ENGINE | NULL | GPL | | ARCHIVE | ACTIVE | STORAGE ENGINE | NULL | GPL | | BLACKHOLE | ACTIVE | STORAGE ENGINE | NULL | GPL | | CSV | ACTIVE | STORAGE ENGINE | NULL | GPL | | FEDERATED | DISABLED | STORAGE ENGINE | NULL | GPL | | MEMORY | ACTIVE | STORAGE ENGINE | NULL | GPL | | InnoDB | ACTIVE | STORAGE ENGINE | NULL | GPL | | MyISAM | ACTIVE | STORAGE ENGINE | NULL | GPL | | MRG_MYISAM | ACTIVE | STORAGE ENGINE | NULL | GPL | | ndbcluster | ACTIVE | STORAGE ENGINE | NULL | GPL | _| ndbinfo | ACTIVE | STORAGE ENGINE | NULL | GPL |_ +------------+----------+----------------+---------+---------+ 12 rows in set (0.00 sec) You can also do this by checking the output of *Note `SHOW ENGINES': show-engines. for a line including `ndbinfo' in the `Engine' column and `YES' in the `Support' column, as shown here (emphasized text): mysql> SHOW ENGINES; +------------+---------+----------------------------------------------------------------+--------------+------+------------+ | Engine | Support | Comment | Transactions | XA | Savepoints | +------------+---------+----------------------------------------------------------------+--------------+------+------------+ | ndbcluster | YES | Clustered, fault-tolerant tables | YES | NO | NO | | MRG_MYISAM | YES | Collection of identical MyISAM tables | NO | NO | NO | _| ndbinfo | YES | MySQL Cluster system information storage engine | NO | NO | NO |_ | CSV | YES | CSV storage engine | NO | NO | NO | | MEMORY | YES | Hash based, stored in memory, useful for temporary tables | NO | NO | NO | | FEDERATED | NO | Federated MySQL storage engine | NULL | NULL | NULL | | ARCHIVE | YES | Archive storage engine | NO | NO | NO | | InnoDB | YES | Supports transactions, row-level locking, and foreign keys | YES | YES | YES | | MyISAM | DEFAULT | Default engine as of MySQL 3.23 with great performance | NO | NO | NO | | BLACKHOLE | YES | /dev/null storage engine (anything you write to it disappears) | NO | NO | NO | +------------+---------+----------------------------------------------------------------+--------------+------+------------+ 10 rows in set (0.00 sec) If `ndbinfo' support is enabled, then you can access `ndbinfo' using SQL statements in *Note `mysql': mysql. or another MySQL client. For example, you can see `ndbinfo' listed in the output of *Note `SHOW DATABASES': show-databases, as shown here: mysql> SHOW DATABASES; +--------------------+ | Database | +--------------------+ | information_schema | | mysql | | ndbinfo | | test | +--------------------+ 4 rows in set (0.00 sec) If the *Note `mysqld': mysqld. process was not started with the `--ndbcluster' option, `ndbinfo' is not available and is not displayed by *Note `SHOW DATABASES': show-databases. If *Note `mysqld': mysqld. was formerly connected to a MySQL Cluster but the cluster becomes unavailable (due to events such as cluster shutdown, loss of network connectivity, and so forth), `ndbinfo' and its tables remain visible, but an attempt to access any tables (other than `blocks' or `config_params') fails with `Got error 157 'Connection to NDB failed' from NDBINFO'. *Note*: With the exception of the `blocks' and `config_params' tables, what we refer to as `ndbinfo' `tables' are actually views generated from internal *Note `NDB': mysql-cluster. tables not visible to the MySQL Server. All `ndbinfo' tables are read-only. Beginning with MySQL Cluster NDB 7.0.22 and MySQL Cluster NDB 7.1.11, `ndbinfo' tables are not included in the query cache. (Bug#59831) You can select the `ndbinfo' database with a *Note `USE': use. statement, and then issue a *Note `SHOW TABLES': show-tables. statement to obtain a list of tables, just as for any other database, like this: mysql> USE ndbinfo; Database changed mysql> SHOW TABLES; +-------------------+ | Tables_in_ndbinfo | +-------------------+ | blocks | | config_params | | counters | | diskpagebuffer | | logbuffers | | logspaces | | memoryusage | | nodes | | resources | | transporters | +-------------------+ 9 rows in set (0.00 sec) The *Note `diskpagebuffer': mysql-cluster-ndbinfo-diskpagebuffer. table was added in MySQL Cluster NDB 7.1.9. In early versions of MySQL Cluster NDB 7.1, there was an additional *Note `pools': mysql-cluster-ndbinfo-pools. table in the `ndbinfo' database; however, this table was removed in MySQL Cluster NDB 7.1.3. You can execute *Note `SELECT': select. statements against these tables, just as you would normally expect: mysql> SELECT * FROM memoryusage; +---------+--------------+------+-------+ | node_id | DATA_MEMORY | used | max | +---------+--------------+------+-------+ | 1 | DATA_MEMORY | 3230 | 6408 | | 2 | DATA_MEMORY | 3230 | 6408 | | 1 | INDEX_MEMORY | 16 | 12832 | | 2 | INDEX_MEMORY | 16 | 12832 | +---------+--------------+------+-------+ 4 rows in set (0.37 sec) More complex queries, such as the two following *Note `SELECT': select. statements using the *Note `memoryusage': mysql-cluster-ndbinfo-memoryusage. table, are possible: mysql> SELECT SUM(used) as 'Data Memory Used, All Nodes' > FROM memoryusage > WHERE DATA_MEMORY = 'DATA_MEMORY'; +-----------------------------+ | Data Memory Used, All Nodes | +-----------------------------+ | 6460 | +-----------------------------+ 1 row in set (0.37 sec) mysql> SELECT SUM(max) as 'Total IndexMemory Available' > FROM memoryusage > WHERE DATA_MEMORY = 'INDEX_MEMORY'; +-----------------------------+ | Total IndexMemory Available | +-----------------------------+ | 25664 | +-----------------------------+ 1 row in set (0.33 sec) `ndbinfo' table and column names are case sensitive (as is the name of the `ndbinfo' database itself). These identifiers are in lowercase. Trying to use the wrong lettercase results in an error, as shown in this example: mysql> SELECT * FROM nodes; +---------+--------+---------+-------------+ | node_id | uptime | status | start_phase | +---------+--------+---------+-------------+ | 1 | 13602 | STARTED | 0 | | 2 | 16 | STARTED | 0 | +---------+--------+---------+-------------+ 2 rows in set (0.04 sec) mysql> SELECT * FROM Nodes; `ERROR 1146 (42S02): Table 'ndbinfo.Nodes' doesn't exist' *Important*: Beginning with MySQL Cluster NDB 7.1.7, *Note `mysqldump': mysqldump. ignores `ndbinfo' entirely, and excludes it from any output. This is true even when using the `--databases' or `--all-databases' option.  File: manual.info, Node: mysql-cluster-ndbinfo-blocks, Next: mysql-cluster-ndbinfo-config-params, Prev: mysql-cluster-ndbinfo, Up: mysql-cluster-ndbinfo 17.5.9.1 The `ndbinfo blocks' Table ................................... The `blocks' table is a static table which simply contains the names and internal IDs of all NDB kernel blocks (see `NDB' Kernel Blocks (http://dev.mysql.com/doc/ndbapi/en/ndb-internals-kernel-blocks.html)). It is for use by the other *Note `ndbinfo': mysql-cluster-ndbinfo. tables (most of which are actually views) in mapping block numbers to block names for producing human-readable output. The following table provides information about the columns in the `blocks' table. For each column, the table shows the name, data type, and a brief description. Additional information can be found in the notes following the table. Column Name Type Remarks `block_number' integer Block number `block_name' string Block name Although this is a static table, its content could possibly vary between different MySQL Cluster releases.  File: manual.info, Node: mysql-cluster-ndbinfo-config-params, Next: mysql-cluster-ndbinfo-counters, Prev: mysql-cluster-ndbinfo-blocks, Up: mysql-cluster-ndbinfo 17.5.9.2 The `ndbinfo config_params' Table .......................................... The `config_params' table is a static table which provides the names and internal ID numbers of all MySQL Cluster configuration parameters. The following table provides information about the columns in the `config_params' table. For each column, the table shows the name, data type, and a brief description. Additional information can be found in the notes following the table. Column Name Type Remarks `param_number' integer The parameter's internal ID number `param_name' string The name of the parameter Although this is a static table, its content can vary between MySQL Cluster installations, since supported parameters can vary due to differences between software releases, cluster hardware configurations, and other factors.  File: manual.info, Node: mysql-cluster-ndbinfo-counters, Next: mysql-cluster-ndbinfo-diskpagebuffer, Prev: mysql-cluster-ndbinfo-config-params, Up: mysql-cluster-ndbinfo 17.5.9.3 The `ndbinfo counters' Table ..................................... The `counters' table provides running totals of events such as reads and writes for specific kernel blocks and data nodes. Counts are kept from the most recent node start or restart; a node start or restart resets all counters on that node. Not all kernel blocks have all types of counters. The following table provides information about the columns in the `counters' table. For each column, the table shows the name, data type, and a brief description. Additional information can be found in the notes following the table. Column Name Type Remarks `node_id' integer The data node ID `block_name' string Name of the associated NDB kernel block (see `NDB' Kernel Blocks (http://dev.mysql.com/doc/ndbapi/en/ndb-internals-kernel-blocks.html)). `block_instance' integer _REMARK_ `counter_id' integer The counter's internal ID number; normally an integer between 1 and 10, inclusive. `counter_name' string The name of the counter. See text for names of individual counters and the NDB kernel block with which each counter is asoociated. `val' integer The counter's value Each counter is associated with a particular NDB kernel block. Prior to MySQL Cluster NDB 7.2.0, this was limited to either the `DBLQH' kernel block or the `DBTC' kernel block. The `OPERATIONS' counter is associated with the `DBLQH' (local query handler) kernel block (see The `DBLQH' Block (http://dev.mysql.com/doc/ndbapi/en/ndb-internals-kernel-blocks-dblqh.html)). The `ATTRINFO', `TRANSACTIONS', `COMMITS', `READS', `SIMPLE_READS', `WRITES', `ABORTS', `TABLE_SCANS', and `RANGE_SCANS' counters are associated with the DBTC (transaction co-ordinator) kernel block (see The `DBTC' Block (http://dev.mysql.com/doc/ndbapi/en/ndb-internals-kernel-blocks-dbtc.html)). MySQL Cluster NDB 7.2.0, as part of its implementation of distributed pushed-down joins, adds the `LOCAL_TABLE_SCANS_SENT', `READS_RECEIVED', `PRUNED_RANGE_SCANS_RECEIVED', `RANGE_SCANS_RECEIVED', `LOCAL_READS_SENT', `CONST_PRUNED_RANGE_SCANS_RECEIVED', `LOCAL_RANGE_SCANS_SENT', `REMOTE_READS_SENT', `REMOTE_RANGE_SCANS_SENT', `READS_NOT_FOUND', `SCAN_BATCHES_RETURNED', `TABLE_SCANS_RECEIVED', and `SCAN_ROWS_RETURNED' counters. These counters are associated with the `DBSPJ' (select push-down join) kernel block (see The `DBSPJ' Block (http://dev.mysql.com/doc/ndbapi/en/ndb-internals-kernel-blocks-dbspj.html)).  File: manual.info, Node: mysql-cluster-ndbinfo-diskpagebuffer, Next: mysql-cluster-ndbinfo-logbuffers, Prev: mysql-cluster-ndbinfo-counters, Up: mysql-cluster-ndbinfo 17.5.9.4 The `ndbinfo diskpagebuffer' Table ........................................... The `diskpagebuffer' table provides stastistics about disk page buffer usage by MySQL Cluster Disk Data tables. The following table provides information about the columns in the `diskpagebuffer' table. For each column, the table shows the name, data type, and a brief description. Additional information can be found in the notes following the table. Column Name Type Remarks `node_id' integer The data node ID `block_instance' integer _REMARK_ `pages_written' integer Number of pages written to disk. `pages_written_lcp' integer Number of pages written by local checkpoints. `pages_read' integer Number of pages read from disk `log_waits' integer Number of page writes waiting for log to be written to disk `page_requests_direct_return'integer Number of requests for pages that were available in buffer `page_requests_wait_queue'integer Number of requests that had to wait for pages to become available in buffer `page_requests_wait_io'integer Number of requests that had to be read from pages on disk (pages were unavailable in buffer) You can use this table with MySQL Cluster Disk Data tables to determine whether `DiskPageBufferMemory' is sufficiently large to allow data to be read from the buffer rather from disk; minimizing disk seeks can help improve performance of such tables. You can determine the proportion of reads from `DiskPageBufferMemory' to the total number of reads using a query such as this one, which obtains this ratio as a percentage: SELECT node_id, 100 * page_requests_direct_return / (page_requests_direct_return + page_requests_wait_io) AS hit_ratio FROM ndbinfo.diskpagebuffer; The result from this query should be similar to what is shown here, with one row for each data node in the cluster (in this example, the cluster has 4 data nodes): +---------+-----------+ | node_id | hit_ratio | +---------+-----------+ | 5 | 97.6744 | | 6 | 97.6879 | | 7 | 98.1776 | | 8 | 98.1343 | +---------+-----------+ 4 rows in set (0.00 sec) `hit_ratio' values approaching 100% indicate that only a very small number of reads are being made from disk rather than from the buffer, which means that Disk Data read performance is approaching an optimum level. If any of these values are less than 95%, this is a strong indicator that the setting for `DiskPageBufferMemory' needs to be increased in the `config.ini' file. *Note*: A change in `DiskPageBufferMemory' requires a rolling restart of all of the cluster's data nodes before it takes effect.  File: manual.info, Node: mysql-cluster-ndbinfo-logbuffers, Next: mysql-cluster-ndbinfo-logspaces, Prev: mysql-cluster-ndbinfo-diskpagebuffer, Up: mysql-cluster-ndbinfo 17.5.9.5 The `ndbinfo logbuffers' Table ....................................... The `logbuffer' table provides information on MySQL Cluster log buffer usage. The following table provides information about the columns in the `logbuffers' table. For each column, the table shows the name, data type, and a brief description. Column Name Type Remarks `node_id' integer The ID of this data node. `log_type' string Type of log; one of: `REDO' or `DD-UNDO'. `log_id' integer The log ID. `log_part' integer The log part number. `total' integer Total space available for this log. `used' integer Space used by this log.  File: manual.info, Node: mysql-cluster-ndbinfo-logspaces, Next: mysql-cluster-ndbinfo-memoryusage, Prev: mysql-cluster-ndbinfo-logbuffers, Up: mysql-cluster-ndbinfo 17.5.9.6 The `ndbinfo logspaces' Table ...................................... This table provides information about MySQL Cluster log space usage. The following table provides information about the columns in the `logspaces' table. For each column, the table shows the name, data type, and a brief description. Column Name Type Remarks `node_id' integer The ID of this data node. `log_type' string Type of log; one of: `REDO' or `DD-UNDO'. `log_id' integer The log ID. `log_part' integer The log part number. `total' integer Total space available for this log. `used' integer Space used by this log.  File: manual.info, Node: mysql-cluster-ndbinfo-memoryusage, Next: mysql-cluster-ndbinfo-nodes, Prev: mysql-cluster-ndbinfo-logspaces, Up: mysql-cluster-ndbinfo 17.5.9.7 The `ndbinfo memoryusage' Table ........................................ Querying this table provides information similar to that provided by the `ALL REPORT MemoryUsage' command in the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client, or logged by `ALL DUMP 1000'. The following table provides information about the columns in the `memoryusage' table in MySQL Cluster NDB 7.1.3 and later. For each column, the table shows the name, data type, and a brief description. Additional information can be found in the notes following the table. Column Name Type Remarks `node_id' integer The node ID of this data node. `memory_type' string One of `DATA_MEMORY' or `INDEX_MEMORY'. `used' integer Number of bytes currently used for data memory or index memory by this data node. `used_pages' integer Number of pages currently used for data memory or index memory by this data node; see text. `total' integer Total number of bytes of data memory or index memory available for this data node; see text. `total_pages' integer Total number of memory pages available for data memory or index memory on this data node; see text. The `total' column represents the total amount of memory in bytes available for the given resource (data memory or index memory) on a particular data node. This number should be approximately equal to the setting of the corresponding configuration parameter in the `config.ini' file. Suppose that the cluster has 2 data nodes having node IDs `1' and `2', and the `config.ini' file contains the following: [ndbd default] DataMemory = 100M IndexMemory = 100M The following query shows approximately the same values: mysql> SELECT node_id, memory_type, total > FROM ndbinfo.memoryusage; +---------+--------------+-----------+ | node_id | memory_type | total | +---------+--------------+-----------+ | 1 | Data memory | 104857600 | | 1 | Index memory | 105119744 | | 2 | Data memory | 104857600 | | 2 | Index memory | 105119744 | +---------+--------------+-----------+ 4 rows in set (0.30 sec) In this case, the `total' column values for index memory are slightly higher than the value set of `IndexMemory' due to internal rounding. For the `used_pages' and `total_pages' columns, resources are measured in pages, which are 32K in size for `DataMemory' and 8K for `IndexMemory'. MySQL Cluster NDB 7.1.2 and earlier The the remainder of this section provides information about the `memoryusage' table as implemented prior to MySQL Cluster NDB 7.1.3. (If you are using MySQL Cluster NDB 7.1.3 or later, refer to the beginning of this section.) For each column, the table shown here provides the name, data type, and a brief description. Additional information can be found in the notes following the table. Column Name Type Remarks `node_id' integer The node ID of this data node. `memory_type' string One of `DATA_MEMORY' or `INDEX_MEMORY' `used' integer Number of memory pages used; see text. `max' integer Total number of memory pages available; see text. For the `used' and `max' columns, resources are measured in pages, which (in MySQL Cluster NDB 7.1.2 and earlier) are 16K in size for `DataMemory' and 8K for `IndexMemory'. This example shows how to use this information in obtaining totals for `DataMemory', `IndexMemory', or both, which you can do by summing across data nodes and table columns, like this: mysql> USE ndbinfo; Database changed mysql> SET @IPAGE := 8 * 1024; Query OK, 0 rows affected (0.03 sec) mysql> SET @DPAGE := 2 * @IPAGE; Query OK, 0 rows affected (0.00 sec) mysql> SELECT -> @DPAGE * SUM(used) as 'Total DataMemory Used', -> @DPAGE * SUM(max) as 'Total DataMemory Available', -> @DPAGE * SUM(used) DIV COUNT(*) as 'Average DataMemory Used Per Node', -> @DPAGE * SUM(max) DIV COUNT(*) as 'Average DataMemory Available Per Node' -> FROM memoryusage WHERE memory_type = 'DATA_MEMORY'\G *************************** 1. row *************************** Total DataMemory Used: 106102784 Total DataMemory Available: 209977344 Average DataMemory Used Per Node: 53051392 Average DataMemory Available Per Node: 104988672 1 row in set (0.34 sec) mysql> SELECT -> @IPAGE * SUM(used) as 'Total IndexMemory Used', -> @IPAGE * SUM(max) as 'Total IndexMemory Available', -> @IPAGE * SUM(used) DIV COUNT(*) as 'Average IndexMemory Used Per Node', -> @IPAGE * SUM(max) DIV COUNT(*) as 'Average IndexMemory Available Per Node' -> FROM memoryusage WHERE memory_type = 'INDEX_MEMORY'\G *************************** 1. row *************************** Total IndexMemory Used: 376832 Total IndexMemory Available: 210239488 Average IndexMemory Used Per Node: 188416 Average IndexMemory Available Per Node: 105119744 1 row in set (0.33 sec) (We use `DIV' rather than `/' in both queries so that the results in all of the output columns are integers.) Prior to MySQL Cluster NDB 7.1.2, the `memory_type' column was named `DATA_MEMORY'. (Bug#50926)  File: manual.info, Node: mysql-cluster-ndbinfo-nodes, Next: mysql-cluster-ndbinfo-pools, Prev: mysql-cluster-ndbinfo-memoryusage, Up: mysql-cluster-ndbinfo 17.5.9.8 The `ndbinfo nodes' Table .................................. This table contains information on the status of data nodes. For each data node that is running in the cluster, a corresponding row in this table provides the node's node ID, status, and uptime. For nodes that are starting, it also shows the current start phase. The following table provides information about the columns in the `nodes' table. For each column, the table shows the name, data type, and a brief description. Additional information can be found in the notes following the table. Column Name Type Remarks `node_id' integer The data node's unique node ID in the cluster. `uptime' integer Time since the node was last started, in seconds. `status' string Current status of the data node; see text for possible values. `start_phase' integer If the data node is starting, the current start phase. `config_generation' integer The version of the cluster configuration file in use on this data node. The `uptime' column shows the time in seconds that this node has been running since it was last started or restarted. This is a *Note `BIGINT': numeric-types. value. This figure includes the time actually needed to start the node; in other words, this counter starts running the moment that *Note `ndbd': mysql-cluster-programs-ndbd. or *Note `ndbmtd': mysql-cluster-programs-ndbmtd. is first invoked; thus, even for a node that has not yet finished starting, `uptime' may show a non-zero value. The `status' column shows the node's current status. This is one of: `NOTHING', `CMVMI', `STARTING', `STARTED', `SINGLEUSER', `STOPPING_1', `STOPPING_2', `STOPPING_3', or `STOPPING_4'. When the status is `STARTING', you can see the current start phase in the `start_phase' column (see later in this section). `SINGLEUSER' is displayed in the `status' column for all data nodes when the cluster is in single user mode (see *Note mysql-cluster-single-user-mode::). Seeing one of the `STOPPING' states does not necessarily mean that the node is shutting down but can mean rather that it is entering a new state; for example, if you put the cluster in single user mode, you can sometimes see data nodes report their state briefly as `STOPPING_2' before the status changes to `SINGLEUSER'. The `start_phase' column uses the same range of values as those used in the output of the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client `NODE_ID STATUS' command (see *Note mysql-cluster-mgm-client-commands::). If the node is not currently starting, then this column shows `0'. For a listing of MySQL Cluster start phases with descriptions, see *Note mysql-cluster-start-phases::. The `config_generation' column was added in MySQL Cluster NDB 7.0.24 and MySQL Cluster NDB 7.1.13. This column shows which version of the cluster configuration is in effect on each data node. This can be useful when performing a rolling restart of the cluster in order to make changes in configuration parameters. For example, from the output of the following *Note `SELECT': select. statement, you can see that node 3 is not yet using the latest version of the cluster configuration (`6') although nodes 1, 2, and 4 are doing so: mysql> USE ndbinfo; Database changed mysql> SELECT * FROM nodes; +---------+--------+---------+-------------+-------------------+ | node_id | uptime | status | start_phase | config_generation | +---------+--------+---------+-------------+-------------------+ | 1 | 10462 | STARTED | 0 | 6 | | 2 | 10460 | STARTED | 0 | 6 | | 3 | 10457 | STARTED | 0 | 5 | | 4 | 10455 | STARTED | 0 | 6 | +---------+--------+---------+-------------+-------------------+ 2 rows in set (0.04 sec) Therefore, for the case just shown, you should restart node 3 to complete the rolling restart of the cluster. *Note*: When upgrading to MySQL Cluster NDB 7.0.24 or MySQL Cluster NDB 7.1.13 from a previous version of MySQL Cluster, you should run *Note `mysql_upgrade': mysql-upgrade. on all MySQL Servers that should connect to the cluster, in order to enable support for the new `config_generation' column. Otherwise, when you attempt to access this table, you get the warning `Table 'ndb$nodes' is defined differently in NDB, there are more columns available...' Nodes that are stopped are not accounted for in this table. Suppose that you have a MySQL Cluster with 4 data nodes (node IDs 1, 2, 3 and 4), and all nodes are running normally, then this table contains 4 rows, 1 for each data node: mysql> USE ndbinfo; Database changed mysql> SELECT * FROM nodes; +---------+--------+---------+-------------+-------------------+ | node_id | uptime | status | start_phase | config_generation | +---------+--------+---------+-------------+-------------------+ | 1 | 11776 | STARTED | 0 | 6 | | 2 | 11774 | STARTED | 0 | 6 | | 3 | 11771 | STARTED | 0 | 6 | | 4 | 11769 | STARTED | 0 | 6 | +---------+--------+---------+-------------+-------------------+ 4 rows in set (0.04 sec) If you shut down one of the nodes, only the nodes that are still running are represented in the output of this *Note `SELECT': select. statement, as shown here: ndb_mgm> 2 STOP Node 2: Node shutdown initiated Node 2: Node shutdown completed. Node 2 has shutdown. mysql> SELECT * FROM nodes; +---------+--------+---------+-------------+-------------------+ | node_id | uptime | status | start_phase | config_generation | +---------+--------+---------+-------------+-------------------+ | 1 | 11807 | STARTED | 0 | 6 | | 3 | 11802 | STARTED | 0 | 6 | | 4 | 11800 | STARTED | 0 | 6 | +---------+--------+---------+-------------+-------------------+ 3 rows in set (0.02 sec)  File: manual.info, Node: mysql-cluster-ndbinfo-pools, Next: mysql-cluster-ndbinfo-resources, Prev: mysql-cluster-ndbinfo-nodes, Up: mysql-cluster-ndbinfo 17.5.9.9 The `ndbinfo pools' Table .................................. *Important*: This table was part of the original `ndbinfo' implementation, but was later removed (in MySQL Cluster NDB 7.1.3). The information in this section is now obsolete, and subject to removal in a future version of the documentation. The `pools' table was originally intended to provide information about *Note `NDB': mysql-cluster. memory pool usage, but was later removed. For each column, this table shows the name, data type, and a brief description of each `ndbinfo.pools' column (as it appeared prior to MySQL Cluster NDB 7.1.3). Additional information can be found in the notes afterward. Column Name Type Remarks `node_id' integer The data node's node ID. `block_name' string Name of the NDB kernel block using this pool. `block_instance' integer Kernel block instance ID. `pool_name' string The name of the pool. `used' integer Amount of the pool in use. `total' integer Total size of the pool. `high' integer The maximum used from this pool (since the node was last started). `entry_size' integer The size of each object, in bytes. `param_name1' string Name of a configuration parameter associated with this pool (or `NULL'); see text. `param_name2' string Name of a configuration parameter associated with this pool (or `NULL'); see text. `param_name3' string Name of a configuration parameter associated with this pool (or `NULL'); see text. `param_name4' string Name of a configuration parameter associated with this pool (or `NULL'); see text. The columns `param_name1', `param_name2', `param_name3', and `param_name4' contain names of configuration parameters that are associated with a given pool. If no parameters are associated with the pool, then all 4 of these columns are `NULL'. For pools that are associated with configuration parameters, these columns are not filled with non-`NULL' values in any particular order, as shown in this example: mysql> SELECT -> DISTINCT(pool_name), block_name, param_name1, param_name2, param_name3, param_name4 -> FROM ndbinfo.pools -> WHERE pool_name = 'Table'; +-----------+------------+---------------+---------------+-----------------------+--------------------------+ | pool_name | block_name | param_name1 | param_name2 | param_name3 | param_name4 | +-----------+------------+---------------+---------------+-----------------------+--------------------------+ | Table | BACKUP | NULL | MaxNoOfTables | MaxNoOfOrderedIndexes | MaxNoOfUniqueHashIndexes | | Table | SUMA | MaxNoOfTables | NULL | NULL | NULL | +-----------+------------+---------------+---------------+-----------------------+--------------------------+ 2 rows in set (0.29 sec) You can use a query such as the one shown here to generate a table showing the associations of pools, NDB kernel blocks, and (where applicable) configuration parameters: SELECT DISTINCT(pool_name) as 'Pool', block_name as 'Block', IF( (param_name1 && param_name2 && param_name3 && param_name4) IS NULL, '[NONE]', REPLACE( TRIM( CONCAT( IFNULL(param_name1, ''), IFNULL(CONCAT(' ', param_name2), ''), IFNULL(CONCAT(' ', param_name3), ''), IFNULL(CONCAT(' ', param_name4), '') ) ), ' ', ', ' ) ) as 'Parameter(s)' FROM pools ORDER BY pool_name; You may also find the following stored procedure useful. It returns a list of pools associated with a given configuration parameter, along with the kernel blocks to which these pools belong. You can see here the statement used to create this stored procedure along with sample output for some typical parameters: mysql> DELIMITER | mysql> CREATE PROCEDURE get_pools (p VARCHAR(50)) -> BEGIN -> SELECT -> DISTINCT(pool_name) as Pool, -> block_name as Block -> FROM ndbinfo.pools -> WHERE p -> IN (param_name1, param_name2, param_name3, param_name4) .> ORDER BY Pool; -> END -> | Query OK, 0 rows affected (0.02 sec) mysql> DELIMITER ; mysql> CALL get_pools('MaxNoOfTables'); +-----------------+------------+ | pool_name | block_name | +-----------------+------------+ | Table Record | DBDICT | | DictObject | DBDICT | | Index | DBTC | | Table | BACKUP | | Trigger | BACKUP | | Fragment | BACKUP | | Subscriber | SUMA | | Table | SUMA | | Subscription | SUMA | | Index | DBTUX | | Descriptor page | DBTUX | +-----------------+------------+ 11 rows in set (0.30 sec) Query OK, 0 rows affected (0.30 sec) mysql> CALL get_pools('MaxNoOfOrderedIndexes'); +-----------------+------------+ | pool_name | block_name | +-----------------+------------+ | DictObject | DBDICT | | Index | DBTC | | Table | BACKUP | | Trigger | BACKUP | | Fragment | BACKUP | | Index | DBTUX | | Fragment | DBTUX | | Descriptor page | DBTUX | +-----------------+------------+ 8 rows in set (0.29 sec)  File: manual.info, Node: mysql-cluster-ndbinfo-resources, Next: mysql-cluster-ndbinfo-transporters, Prev: mysql-cluster-ndbinfo-pools, Up: mysql-cluster-ndbinfo 17.5.9.10 The `ndbinfo resources' Table ....................................... This table provides information about data node resource availability and usage. These resources are sometimes known as _super-pools_. The following table provides information about the columns in the `resources' table. For each column, the table shows the name, data type, and a brief description. Additional information can be found in the notes following the table. Column Name Type Remarks `node_id' integer The unique node ID of this data node. `resource_name' string Name of the resource; see text. `reserved' integer The amount reserved for this resource. `used' integer The amount actually used by this resource. `max' integer The maximum amount of this resource used, since the node was last started. The `resource_name' can be one of `RESERVED', `DISK_OPERATIONS', `DISK_RECORDS', `DATA_MEMORY', `JOBBUFFER', `FILE_BUFFERS', or `TRANSPORTER_BUFFERS'.  File: manual.info, Node: mysql-cluster-ndbinfo-transporters, Prev: mysql-cluster-ndbinfo-resources, Up: mysql-cluster-ndbinfo 17.5.9.11 The `ndbinfo transporters' Table .......................................... This table contains information about NDB transporters. The following table provides information about the columns in the `transporters' table. For each column, the table shows the name, data type, and a brief description. Additional information can be found in the notes following the table. Column Name Type Remarks `node_id' integer This data node's unique node ID in the cluster. `remote_node_id' integer The remote data node's node ID. `status' string Status of the connection. For each running data node in the cluster, the `transporters' table displays a row showing the status of each of that node's connections with all nodes in the cluster, _including itself_. This information is shown in the table's _status_ column, which can have any one of the following values: `CONNECTING', `CONNECTED', `DISCONNECTING', or `DISCONNECTED'. Connections to API and management nodes which are configured but not currently connected to the cluster are shown with status `DISCONNECTED'. Rows where the `node_id' is that of a data nodes which is not currently connected are not shown in this table. (This is similar omission of disconnected nodes in the *Note `ndbinfo.nodes': mysql-cluster-ndbinfo-nodes. table. Assume you have a 5-node cluster conisting of 2 data nodes, 2 SQL nodes, and 1 management node, as shown in the output of the `SHOW' command in the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client: ndb_mgm> SHOW Connected to Management Server at: localhost:1186 Cluster Configuration --------------------- [ndbd(NDB)] 2 node(s) id=1 @10.100.10.1 (mysql-5.1.41 ndb-7.1.1, Nodegroup: 0, Master) id=2 @10.100.10.2 (mysql-5.1.41 ndb-7.1.1, Nodegroup: 0) [ndb_mgmd(MGM)] 1 node(s) id=10 @10.100.10.10 (mysql-5.1.41 ndb-7.1.1) [mysqld(API)] 2 node(s) id=20 @10.100.10.20 (mysql-5.1.41 ndb-7.1.1) id=21 @10.100.10.21 (mysql-5.1.41 ndb-7.1.1) There are 10 rows in the `transporters' table--5 for the first data node, and 5 for the second--assuming that all data nodes are running, as shown here: mysql> SELECT * FROM transporters; +---------+----------------+---------------+ | node_id | remote_node_id | status | +---------+----------------+---------------+ | 1 | 1 | CONNECTED | | 1 | 2 | CONNECTED | | 1 | 10 | CONNECTED | | 1 | 20 | CONNECTED | | 1 | 21 | CONNECTED | | 2 | 1 | CONNECTED | | 2 | 2 | CONNECTED | | 2 | 10 | CONNECTED | | 2 | 20 | CONNECTED | | 2 | 21 | CONNECTED | +---------+----------------+---------------+ 10 rows in set (0.04 sec) If you shut down one of the data nodes in this cluster using the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client `STOP' command, then repeat the query, this table now shows only 5 rows--1 row for each connection from the remaining data node to another node, including both itself and the data node that is currently offline, as shown here: mysql> SELECT * FROM transporters; +---------+----------------+---------------+ | node_id | remote_node_id | status | +---------+----------------+---------------+ | 1 | 1 | CONNECTED | | 1 | 2 | CONNECTED | | 1 | 10 | CONNECTED | | 1 | 20 | CONNECTED | | 1 | 21 | CONNECTED | +---------+----------------+---------------+ 5 rows in set (0.02 sec)  File: manual.info, Node: mysql-cluster-security, Next: mysql-cluster-disk-data, Prev: mysql-cluster-ndbinfo, Up: mysql-cluster-management 17.5.10 MySQL Cluster Security Issues ------------------------------------- * Menu: * mysql-cluster-security-networking-issues:: MySQL Cluster Security and Networking Issues * mysql-cluster-security-mysql-privileges:: MySQL Cluster and MySQL Privileges * mysql-cluster-security-mysql-security-procedures:: MySQL Cluster and MySQL Security Procedures This section discusses security considerations to take into account when setting up and running MySQL Cluster. Topics covered in this section include the following: * MySQL Cluster and network security issues * Configuration issues relating to running MySQL Cluster securely * MySQL Cluster and the MySQL privilege system * MySQL standard security procedures as applicable to MySQL Cluster  File: manual.info, Node: mysql-cluster-security-networking-issues, Next: mysql-cluster-security-mysql-privileges, Prev: mysql-cluster-security, Up: mysql-cluster-security 17.5.10.1 MySQL Cluster Security and Networking Issues ...................................................... In this section, we discuss basic network security issues as they relate to MySQL Cluster. It is extremely important to remember that MySQL Cluster `out of the box' is not secure; you or your network administrator must take the proper steps to ensure that your cluster cannot be compromised over the network. Cluster communication protocols are inherently insecure, and no encryption or similar security measures are used in communications between nodes in the cluster. Because network speed and latency have a direct impact on the cluster's efficiency, it is also not advisable to employ SSL or other encryption to network connections between nodes, as such schemes will effectively slow communications. It is also true that no authentication is used for controlling API node access to a MySQL Cluster. As with encryption, the overhead of imposing authentication requirements would have an adverse impact on Cluster performance. In addition, there is no checking of the source IP address for either of the following when accessing the cluster: * SQL or API nodes using `free slots' created by empty `[mysqld]' or `[api]' sections in the `config.ini' file This means that, if there are any empty `[mysqld]' or `[api]' sections in the `config.ini' file, then any API nodes (including SQL nodes) that know the management server's host name (or IP address) and port can connect to the cluster and access its data without restriction. (See *Note mysql-cluster-security-mysql-privileges::, for more information about this and related issues.) *Note*: You can exercise some control over SQL and API node access to the cluster by specifying a `HostName' parameter for all `[mysqld]' and `[api]' sections in the `config.ini' file. However, this also means that, should you wish to connect an API node to the cluster from a previously unused host, you need to add an `[api]' section containing its host name to the `config.ini' file. More information is available elsewhere in this chapter about the `HostName' parameter. Also see *Note mysql-cluster-quick::, for configuration examples using `HostName' with API nodes. * Any *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client This means that any cluster management client that is given the management server's host name (or IP address) and port (if not the standard port) can connect to the cluster and execute any management client command. This includes commands such as `ALL STOP' and `SHUTDOWN'. For these reasons, it is necessary to protect the cluster on the network level. The safest network configuration for Cluster is one which isolates connections between Cluster nodes from any other network communications. This can be accomplished by any of the following methods: 1. Keeping Cluster nodes on a network that is physically separate from any public networks. This option is the most dependable; however, it is the most expensive to implement. We show an example of a MySQL Cluster setup using such a physically segregated network here: MySQL Cluster on a private network protected with a hardware firewall This setup has two networks, one private (solid box) for the Cluster management servers and data nodes, and one public (dotted box) where the SQL nodes reside. (We show the management and data nodes connected using a gigabit switch since this provides the best performance.) Both networks are protected from the outside by a hardware firewall, sometimes also known as a _network-based firewall_. This network setup is safest because no packets can reach the cluster's management or data nodes from outside the network--and none of the cluster's internal communications can reach the outside--without going through the SQL nodes, as long as the SQL nodes do not permit any packets to be forwarded. This means, of course, that all SQL nodes must be secured against hacking attempts. *Important*: With regard to potential security vulnerabilities, an SQL node is no different from any other MySQL server. See *Note security-against-attack::, for a description of techniques you can use to secure MySQL servers. 2. Using one or more software firewalls (also known as _host-based firewalls_) to control which packets pass through to the cluster from portions of the network that do not require access to it. In this type of setup, a software firewall must be installed on every host in the cluster which might otherwise be accessible from outside the local network. The host-based option is the least expensive to implement, but relies purely on software to provide protection and so is the most difficult to keep secure. This type of network setup for MySQL Cluster is illustrated here: MySQL Cluster deployed on a network using software firewalls to create public and private zones Using this type of network setup means that there are two zones of MySQL Cluster hosts. Each cluster host must be able to communicate with all of the other machines in the cluster, but only those hosting SQL nodes (dotted box) can be permitted to have any contact with the outside, while those in the zone containing the data nodes and management nodes (solid box) must be isolated from any machines that are not part of the cluster. Applications using the cluster and user of those applications must _not_ be permitted to have direct access to the management and data node hosts. To accomplish this, you must set up software firewalls that limit the traffic to the type or types shown in the following table, according to the type of node that is running on each cluster host computer: Type of Node to Traffic to Permit be Accessed SQL or API node * It originates from the IP address of a management or data node (using any TCP or UDP port). * It originates from within the network in which the cluster resides and is on the port that your application is using. Data node or * It originates from the IP address of a Management node management or data node (using any TCP or UDP port). * It originates from the IP address of an SQL or API node. Any traffic other than that shown in the table for a given node type should be denied. The specifics of configuring a firewall vary from firewall application to firewall application, and are beyond the scope of this Manual. `iptables' is a very common and reliable firewall application, which is often used with `APF' as a front end to make configuration easier. You can (and should) consult the documentation for the software firewall that you employ, should you choose to implement a MySQL Cluster network setup of this type, or of a `mixed' type as discussed under the next item. 3. It is also possible to employ a combination of the first two methods, using both hardware and software to secure the cluster--that is, using both network-based and host-based firewalls. This is between the first two schemes in terms of both security level and cost. This type of network setup keeps the cluster behind the hardware firewall, but permits incoming packets to travel beyond the router connecting all cluster hosts to reach the SQL nodes. One possible network deployment of a MySQL Cluster using hardware and software firewalls in combination is shown here: Network setup for MySQL Cluster using a combination of hardware and software firewalls to provide protection In this case, you can set the rules in the hardware firewall to deny any external traffic except to SQL nodes and API nodes, and then permit traffic to them only on the ports required by your application. Whatever network configuration you use, remember that your objective from the viewpoint of keeping the cluster secure remains the same--to prevent any unessential traffic from reaching the cluster while ensuring the most efficient communication between the nodes in the cluster. Because MySQL Cluster requires large numbers of ports to be open for communications between nodes, the recommended option is to use a segregated network. This represents the simplest way to prevent unwanted traffic from reaching the cluster. *Note*: If you wish to administer a MySQL Cluster remotely (that is, from outside the local network), the recommended way to do this is to use `ssh' or another secure login shell to access an SQL node host. From this host, you can then run the management client to access the management server safely, from within the Cluster's own local network. Even though it is possible to do so in theory, it is _not_ recommended to use *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. to manage a Cluster directly from outside the local network on which the Cluster is running. Since neither authentication nor encryption takes place between the management client and the management server, this represents an extremely insecure means of managing the cluster, and is almost certain to be compromised sooner or later.  File: manual.info, Node: mysql-cluster-security-mysql-privileges, Next: mysql-cluster-security-mysql-security-procedures, Prev: mysql-cluster-security-networking-issues, Up: mysql-cluster-security 17.5.10.2 MySQL Cluster and MySQL Privileges ............................................ In this section, we discuss how the MySQL privilege system works in relation to MySQL Cluster and the implications of this for keeping a MySQL Cluster secure. Standard MySQL privileges apply to MySQL Cluster tables. This includes all MySQL privilege types (`SELECT' privilege, `UPDATE' privilege, `DELETE' privilege, and so on) granted on the database, table, and column level. As with any other MySQL Server, user and privilege information is stored in the `mysql' system database. The SQL statements used to grant and revoke privileges on *Note `NDB': mysql-cluster. tables, databases containing such tables, and columns within such tables are identical in all respects with the *Note `GRANT': grant. and *Note `REVOKE': revoke. statements used in connection with database objects involving any (other) MySQL storage engine. The same thing is true with respect to the *Note `CREATE USER': create-user. and *Note `DROP USER': drop-user. statements. It is important to keep in mind that, by default, the MySQL grant tables use the `MyISAM' storage engine. Because of this, those tables are not duplicated or shared among MySQL servers acting as SQL nodes in a MySQL Cluster. By way of example, suppose that two SQL nodes *A* and *B* are connected to the same MySQL Cluster, which has an *Note `NDB': mysql-cluster. table named `mytable' in a database named `mydb', and that you execute an SQL statement on server *A* that creates a new user `jon@localhost' and grants this user the `SELECT' privilege on that table: mysql> GRANT SELECT ON mydb.mytable -> TO jon@localhost IDENTIFIED BY 'mypass'; This user is _not_ created on server *B*. For this to take place, the statement must also be run on server *B*. Similarly, statements run on server *A* and affecting the privileges of existing users on server *A* do not affect users on server *B* unless those statements are actually run on server *B* as well. In other words, _changes in users and their privileges do not automatically propagate between SQL nodes by default_. Prior to MySQL Cluster NDB 7.2, any synchronization of privileges between SQL nodes must be done either manually or by scripting an application that periodically synchronizes the privilege tables on all SQL nodes in the cluster. In MySQL Cluster NDB 7.2 and later, you can enable automatic distribution of MySQL users and privileges across MySQL Cluster SQL nodes; see *Note mysql-cluster-privilege-distribution::, for details. Conversely, because there is no way in MySQL to deny privileges (privileges can either be revoked or not granted in the first place, but not denied as such), there is no special protection for *Note `NDB': mysql-cluster. tables on one SQL node from users that have privileges on another SQL node. (This is true even if you are not using the automatic distribution of user priveleges available in MySQl Cluster NDB 7.2 and later.) The most far-reaching example of this is the MySQL `root' account, which can perform any action on any database object. In combination with empty `[mysqld]' or `[api]' sections of the `config.ini' file, this account can be especially dangerous. To understand why, consider the following scenario: * The `config.ini' file contains at least one empty `[mysqld]' or `[api]' section. This means that the MySQL Cluster management server performs no checking of the host from which a MySQL Server (or other API node) accesses the MySQL Cluster. * There is no firewall, or the firewall fails to protect against access to the MySQL Cluster from hosts external to the network. * The host name or IP address of the MySQL Cluster's management server is known or can be determined from outside the network. If these conditions are true, then anyone, anywhere can start a MySQL Server with `--ndbcluster' `--ndb-connectstring=MANAGEMENT_HOST' and access the MySQL Cluster. Using the MySQL `root' account, this person can then perform the following actions: * Execute a *Note `SHOW DATABASES': show-databases. statement to obtain a list of all *Note `NDB': mysql-cluster. databases * Execute a *Note `SHOW TABLES FROM SOME_DATABASE': show-tables. statement to obtain a list of all *Note `NDB': mysql-cluster. tables in a given database * Run any legal MySQL statements on any of those tables, such as: * `SELECT * FROM SOME_TABLE' to read all the data from any table * `DELETE FROM SOME_TABLE' to delete all the data from a table * `DESCRIBE SOME_TABLE' or `SHOW CREATE TABLE SOME_TABLE' to determine the table schema * `UPDATE SOME_TABLE SET COLUMN1 = ANY_VALUE1' to fill a table column with `garbage' data; this could actually cause much greater damage than simply deleting all the data Even more insidious variations might include statements like these: UPDATE SOME_TABLE SET AN_INT_COLUMN = AN_INT_COLUMN + 1 or UPDATE SOME_TABLE SET A_VARCHAR_COLUMN = REVERSE(A_VARCHAR_COLUMN) Such malicious statements are limited only by the imagination of the attacker. The only tables that would be safe from this sort of mayhem would be those tables that were created using storage engines other than *Note `NDB': mysql-cluster, and so not visible to a `rogue' SQL node. *Note*: A user who can log in as `root' can also access the `INFORMATION_SCHEMA' database and its tables, and so obtain information about databases, tables, stored routines, scheduled events, and any other database objects for which metadata is stored in `INFORMATION_SCHEMA'. It is also a very good idea to use different passwords for the `root' accounts on different cluster SQL nodes (unless you are using distributed privileges as supported in MySQL Cluster NDB 7.2 and later). In sum, you cannot have a safe MySQL Cluster if it is directly accessible from outside your local network. *Important*: _Never leave the MySQL root account password empty_. This is just as true when running MySQL as a MySQL Cluster SQL node as it is when running it as a standalone (non-Cluster) MySQL Server, and should be done as part of the MySQL installation process before configuring the MySQL Server as an SQL node in a MySQL Cluster. Prior to MySQL Cluster NDB 7.2, you should never convert the system tables in the `mysql' database to use the *Note `NDB': mysql-cluster. storage engine. There are a number of reasons why you should not do this, but the most important reason is this: _Many of the SQL statements that affect `mysql' tables storing information about user privileges, stored routines, scheduled events, and other database objects cease to function if these tables are changed to use any storage engine other than `MyISAM'_. This is a consequence of various MySQL Server internals. Beginning with MySQL Cluster NDB 7.2, you can use a stored procedure provided for this purpose (see *Note mysql-cluster-privilege-distribution::), but you are strongly advised not to attempt convert the system tables manually. Otherwise, if you need to synchronize `mysql' system tables between SQL nodes, you can use standard MySQL replication to do so, or employ a script to copy table entries between the MySQL servers. Summary The two most important points to remember regarding the MySQL privilege system with regard to MySQL Cluster are: 1. Prior to MySQL Cluster NDB 7.2 Users and privileges established on one SQL node do not automatically exist or take effect on other SQL nodes in the cluster. Conversely, removing a user or privilege on one SQL node in the cluster does not remove the user or privilege from any other SQL nodes. In MySQL Cluster NDB 7.2 and later You can cause MySQL users and privileges to be distributed automatically among SQL nodes using the SQL script, and the stored procedures which it contains, that are supplied for this purpose. 2. Once a MySQL user is granted privileges on an *Note `NDB': mysql-cluster. table from one SQL node in a MySQL Cluster, that user can `see' any data in that table regardless of the SQL node from which the data originated. (This is true even if you are not using the privilege distribution support available in MySQl Cluster NDB 7.2 or later.)  File: manual.info, Node: mysql-cluster-security-mysql-security-procedures, Prev: mysql-cluster-security-mysql-privileges, Up: mysql-cluster-security 17.5.10.3 MySQL Cluster and MySQL Security Procedures ..................................................... In this section, we discuss MySQL standard security procedures as they apply to running MySQL Cluster. In general, any standard procedure for running MySQL securely also applies to running a MySQL Server as part of a MySQL Cluster. First and foremost, you should always run a MySQL Server as the `mysql' system user; this is no different from running MySQL in a standard (non-Cluster) environment. The `mysql' system account should be uniquely and clearly defined. Fortunately, this is the default behavior for a new MySQL installation. You can verify that the *Note `mysqld': mysqld. process is running as the system user `mysql' by using the system command such as the one shown here: shell> ps aux | grep mysql root 10467 0.0 0.1 3616 1380 pts/3 S 11:53 0:00 \ /bin/sh ./mysqld_safe --ndbcluster --ndb-connectstring=localhost:1186 mysql 10512 0.2 2.5 58528 26636 pts/3 Sl 11:53 0:00 \ /usr/local/mysql/libexec/mysqld --basedir=/usr/local/mysql \ --datadir=/usr/local/mysql/var --user=mysql --ndbcluster \ --ndb-connectstring=localhost:1186 --pid-file=/usr/local/mysql/var/mothra.pid \ --log-error=/usr/local/mysql/var/mothra.err jon 10579 0.0 0.0 2736 688 pts/0 S+ 11:54 0:00 grep mysql If the *Note `mysqld': mysqld. process is running as any other user than `mysql', you should immediately shut it down and restart it as the `mysql' user. If this user does not exist on the system, the `mysql' user account should be created, and this user should be part of the `mysql' user group; in this case, you should also make sure that the MySQL data directory on this system (as set using the `--datadir' option for *Note `mysqld': mysqld.) is owned by the `mysql' user, and that the SQL node's `my.cnf' file includes `user=mysql' in the `[mysqld]' section. Alternatively, you can start the MySQL server process with `--user=mysql' on the command line, but it is preferable to use the `my.cnf' option, since you might forget to use the command-line option and so have *Note `mysqld': mysqld. running as another user unintentionally. The *Note `mysqld_safe': mysqld-safe. startup script forces MySQL to run as the `mysql' user. *Important*: Never run *Note `mysqld': mysqld. as the system root user. Doing so means that potentially any file on the system can be read by MySQL, and thus--should MySQL be compromised--by an attacker. As mentioned in the previous section (see *Note mysql-cluster-security-mysql-privileges::), you should always set a root password for the MySQL Server as soon as you have it running. You should also delete the anonymous user account that is installed by default. You can accomplish these tasks using the following statements: shell> mysql -u root mysql> UPDATE mysql.user -> SET Password=PASSWORD('SECURE_PASSWORD') -> WHERE User='root'; mysql> DELETE FROM mysql.user -> WHERE User=''; mysql> FLUSH PRIVILEGES; Be very careful when executing the *Note `DELETE': delete. statement not to omit the `WHERE' clause, or you risk deleting _all_ MySQL users. Be sure to run the *Note `FLUSH PRIVILEGES': flush. statement as soon as you have modified the `mysql.user' table, so that the changes take immediate effect. Without *Note `FLUSH PRIVILEGES': flush, the changes do not take effect until the next time that the server is restarted. *Note*: Many of the MySQL Cluster utilities such as *Note `ndb_show_tables': mysql-cluster-programs-ndb-show-tables, *Note `ndb_desc': mysql-cluster-programs-ndb-desc, and *Note `ndb_select_all': mysql-cluster-programs-ndb-select-all. also work without authentication and can reveal table names, schemas, and data. By default these are installed on Unix-style systems with the permissions `wxr-xr-x' (755), which means they can be executed by any user that can access the `mysql/bin' directory. See *Note mysql-cluster-programs::, for more information about these utilities.  File: manual.info, Node: mysql-cluster-disk-data, Next: mysql-cluster-online-add-node, Prev: mysql-cluster-security, Up: mysql-cluster-management 17.5.11 MySQL Cluster Disk Data Tables -------------------------------------- * Menu: * mysql-cluster-disk-data-objects:: MySQL Cluster Disk Data Objects * mysql-cluster-disk-data-symlinks:: Using Symbolic Links with Disk Data Objects * mysql-cluster-disk-data-storage-requirements:: MySQL Cluster Disk Data Storage Requirements Beginning with MySQL 5.1.6, it is possible to store the nonindexed columns of *Note `NDB': mysql-cluster. tables on disk, rather than in RAM as with previous versions of MySQL Cluster. As part of implementing MySQL Cluster Disk Data work, a number of improvements were made in MySQL Cluster for the efficient handling of very large amounts (terabytes) of data during node recovery and restart. These include a `no-steal' algorithm for synchronising a starting node with very large data sets. For more information, see the paper `Recovery Principles of MySQL Cluster 5.1 (http://www.vldb2005.org/program/paper/wed/p1108-ronstrom.pdf)', by MySQL Cluster developers Mikael Ronstro"m and Jonas Oreland. MySQL Cluster Disk Data performance can be influenced by a number of configuration parameters. For information about these parameters and their effects, see `MySQL Cluster Disk Data configuration parameters' and `MySQL Cluster Disk Data storage and `GCP Stop' errors' The performance of a MySQL Cluster that uses Disk Data storage can also be greatly improved by separating data node file systems from undo log files and tablespace data files, which can be done using symbolic links. For more information, see *Note mysql-cluster-disk-data-symlinks::.  File: manual.info, Node: mysql-cluster-disk-data-objects, Next: mysql-cluster-disk-data-symlinks, Prev: mysql-cluster-disk-data, Up: mysql-cluster-disk-data 17.5.11.1 MySQL Cluster Disk Data Objects ......................................... MySQL Cluster Disk Data storage is implemented using a number of _Disk Data objects_. These include the following: * _Tablespaces_ act as containers for other Disk Data objects. * _Undo log files_ undo information required for rolling back transactions. * One or more undo log files are assigned to a _log file group_, which is then assigned to a tablespace. * _Data files_ store Disk Data table data. A data file is assigned directly to a tablespace. Undo log files and data files are actual files in the file system of each data node; by default they are placed in `ndb_NODE_ID_fs' in the DATADIR specified in the MySQL Cluster `config.ini' file, and where NODE_ID is the data node's node ID. It is possible to place these elsewhere by specifying either an absolute or relative path as part of the filename when creating the undo log or data file. Statements that create these files are shown later in this section. MySQL Cluster tablespaces and log file groups are not implemented as files. *Important*: Although not all Disk Data objects are implemented as files, they all share the same namespace. This means that _each Disk Data object_ must be uniquely named (and not merely each Disk Data object of a given type). For example, you cannot have a tablespace and a log file group both named `dd1'. Assuming that you have already set up a MySQL Cluster with all nodes (including management and SQL nodes) running MySQL 5.1.6 or newer, the basic steps for creating a Cluster table on disk are as follows: 1. Create a log file group, and assign one or more undo log files to it (an undo log file is also sometimes referred to as an _undofile_). *Note*: In MySQL 5.1 and later, undo log files are necessary only for Disk Data tables. They are no longer used for *Note `NDBCLUSTER': mysql-cluster. tables that are stored only in memory. 2. Create a tablespace; assign the log file group, as well as one or more data files, to the tablespace. 3. Create a Disk Data table that uses this tablespace for data storage. Each of these tasks can be accomplished using SQL statements in the *Note `mysql': mysql. client or other MySQL client application, as shown in the example that follows. 1. We create a log file group named `lg_1' using *Note `CREATE LOGFILE GROUP': create-logfile-group. This log file group is to be made up of two undo log files, which we name `undo_1.log' and `undo_2.log', whose initial sizes are 16 MB and 12 MB, respectively. (The default initial size for an undo log file is 128 MB.) Optionally, you can also specify a size for the log file group's undo buffer, or permit it to assume the default value of 8 MB. In this example, we set the UNDO buffer's size at 2 MB. A log file group must be created with an undo log file; so we add `undo_1.log' to `lg_1' in this *Note `CREATE LOGFILE GROUP': create-logfile-group. statement: CREATE LOGFILE GROUP lg_1 ADD UNDOFILE 'undo_1.log' INITIAL_SIZE 16M UNDO_BUFFER_SIZE 2M ENGINE NDBCLUSTER; To add `undo_2.log' to the log file group, use the following *Note `ALTER LOGFILE GROUP': alter-logfile-group. statement: ALTER LOGFILE GROUP lg_1 ADD UNDOFILE 'undo_2.log' INITIAL_SIZE 12M ENGINE NDBCLUSTER; Some items of note: * The `.log' file extension used here is not required. We use it merely to make the log files easily recognisable. * Every *Note `CREATE LOGFILE GROUP': create-logfile-group. and *Note `ALTER LOGFILE GROUP': alter-logfile-group. statement must include an `ENGINE' clause. In MySQL 5.1 (including MySQL Cluster NDB 6.X and 7.X through 7.1), the permitted values for this clause are *Note `NDBCLUSTER': mysql-cluster. and *Note `NDB': mysql-cluster. *Important*: In MySQL 5.1.8 and later, there can exist only one log file group in the same MySQL Cluster at any given time. * When you add an undo log file to a log file group using `ADD UNDOFILE 'FILENAME'', a file with the name FILENAME is created in the `ndb_NODE_ID_fs' directory within the `DataDir' of each data node in the cluster, where NODE_ID is the node ID of the data node. Each undo log file is of the size specified in the SQL statement. For example, if a MySQL Cluster has 4 data nodes, then the *Note `ALTER LOGFILE GROUP': alter-logfile-group. statement just shown creates 4 undo log files, 1 each on in the data directory of each of the 4 data nodes; each of these files is named `undo_2.log' and each file is 12 MB in size. * `UNDO_BUFFER_SIZE' is limited by the amount of system memory available. * For more information about the *Note `CREATE LOGFILE GROUP': create-logfile-group. statement, see *Note create-logfile-group::. For more information about *Note `ALTER LOGFILE GROUP': alter-logfile-group, see *Note alter-logfile-group::. 2. Now we can create a tablespace, which contains files to be used by MySQL Cluster Disk Data tables for storing their data. A tablespace is also associated with a particular log file group. When creating a new tablespace, you must specify the log file group which it is to use for undo logging; you must also specify a data file. You can add more data files to the tablespace after the tablespace is created; it is also possible to drop data files from a tablespace (an example of dropping data files is provided later in this section). Assume that we wish to create a tablespace named `ts_1' which uses `lg_1' as its log file group. This tablespace is to contain two data files named `data_1.dat' and `data_2.dat', whose initial sizes are 32 MB and 48 MB, respectively. (The default value for `INITIAL_SIZE' is 128 MB.) We can do this using two SQL statements, as shown here: CREATE TABLESPACE ts_1 ADD DATAFILE 'data_1.dat' USE LOGFILE GROUP lg_1 INITIAL_SIZE 32M ENGINE NDBCLUSTER; ALTER TABLESPACE ts_1 ADD DATAFILE 'data_2.dat' INITIAL_SIZE 48M ENGINE NDBCLUSTER; The *Note `CREATE TABLESPACE': create-tablespace. statement creates a tablespace `ts_1' with the data file `data_1.dat', and associates `ts_1' with log file group `lg_1'. The *Note `ALTER TABLESPACE': alter-tablespace. adds the second data file (`data_2.dat'). Some items of note: * As is the case with the `.log' file extension used in this example for undo log files, there is no special significance for the `.dat' file extension; it is used merely for easy recognition of data files. * When you add a data file to a tablespace using `ADD DATAFILE 'FILENAME'', a file with the name FILENAME is created in the `ndb_NODE_ID_fs' directory within the `DataDir' of each data node in the cluster, where NODE_ID is the node ID of the data node. Each undo log file is of the size specified in the SQL statement. For example, if a MySQL Cluster has 4 data nodes, then the *Note `ALTER TABLESPACE': alter-tablespace. statement just shown creates 4 undo log files, 1 each on in the data directory of each of the 4 data nodes; each of these files is named `data_2.dat' and each file is 48 MB in size. * All *Note `CREATE TABLESPACE': create-tablespace. and *Note `ALTER TABLESPACE': alter-tablespace. statements must contain an `ENGINE' clause; only tables using the same storage engine as the tablespace can be created in the tablespace. In MySQL 5.1 (including MySQL Cluster NDB 6.X and 7.X through 7.1), the only permitted values for this clause are *Note `NDBCLUSTER': mysql-cluster. and *Note `NDB': mysql-cluster. * For more information about the *Note `CREATE TABLESPACE': create-tablespace. and *Note `ALTER TABLESPACE': alter-tablespace. statements, see *Note create-tablespace::, and *Note alter-tablespace::. 3. Now it is possible to create a table whose nonindexed columns are stored on disk in the tablespace `ts_1': CREATE TABLE dt_1 ( member_id INT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY, last_name VARCHAR(50) NOT NULL, first_name VARCHAR(50) NOT NULL, dob DATE NOT NULL, joined DATE NOT NULL, INDEX(last_name, first_name) ) TABLESPACE ts_1 STORAGE DISK ENGINE NDBCLUSTER; The `TABLESPACE ... STORAGE DISK' option tells the *Note `NDBCLUSTER': mysql-cluster. storage engine to use tablespace `ts_1' for disk data storage. *Note*: Beginning with MySQL Cluster NDB 6.2.5 and MySQL Cluster NDB 6.3.2, it is also possible to specify whether an individual column is stored on disk or in memory by using a `STORAGE' clause as part of the column's definition in a *Note `CREATE TABLE': create-table. or *Note `ALTER TABLE': alter-table. statement. `STORAGE DISK' causes the column to be stored on disk, and `STORAGE MEMORY' causes in-memory storage to be used. See *Note create-table::, for more information. Once table `ts_1' has been created as shown, you can perform *Note `INSERT': insert, *Note `SELECT': select, *Note `UPDATE': update, and *Note `DELETE': delete. statements on it just as you would with any other MySQL table. For table `dt_1' as it has been defined here, only the `dob' and `joined' columns are stored on disk. This is because there are indexes on the `id', `last_name', and `first_name' columns, and so data belonging to these columns is stored in RAM. In MySQL 5.1 (including MySQL Cluster NDB 6.X and 7.X through 7.1), only nonindexed columns can be held on disk; indexes and indexed column data continue to be stored in memory. This tradeoff between the use of indexes and conservation of RAM is something you must keep in mind as you design Disk Data tables. Performance note The performance of a cluster using Disk Data storage is greatly improved if Disk Data files are kept on a separate physical disk from the data node file system. This must be done for each data node in the cluster to derive any noticeable benefit. You may use absolute and relative file system paths with `ADD UNDOFILE' and `ADD DATAFILE'. Relative paths are calculated relative to the data node's data directory. You may also use symbolic links; see *Note mysql-cluster-disk-data-symlinks::, for more information and examples. A log file group, a tablespace, and any Disk Data tables using these must be created in a particular order. The same is true for dropping any of these objects: * A log file group cannot be dropped as long as any tablespaces are using it. * A tablespace cannot be dropped as long as it contains any data files. * You cannot drop any data files from a tablespace as long as there remain any tables which are using the tablespace. * Beginning with MySQL 5.1.12, it is no longer possible to drop files created in association with a different tablespace than the one with which the files were created. (Bug#20053) For example, to drop all the objects created so far in this section, you would use the following statements: mysql> DROP TABLE dt_1; mysql> ALTER TABLESPACE ts_1 -> DROP DATAFILE 'data_2.dat' -> ENGINE NDBCLUSTER; mysql> ALTER TABLESPACE ts_1 -> DROP DATAFILE 'data_1.dat' -> ENGINE NDBCLUSTER; mysql> DROP TABLESPACE ts_1 -> ENGINE NDBCLUSTER; mysql> DROP LOGFILE GROUP lg_1 -> ENGINE NDBCLUSTER; These statements must be performed in the order shown, except that the two `ALTER TABLESPACE ... DROP DATAFILE' statements may be executed in either order. You can obtain information about data files used by Disk Data tables by querying the *Note `FILES': files-table. table in the `INFORMATION_SCHEMA' database. An extra ``NULL' row' was added to this table in MySQL 5.1.14 for providing additional information about undo log files. For more information and examples of use, see *Note files-table::. Beginning with MySQL Cluster NDB 6.3.27 and MySQL Cluster NDB 7.0.8, it is also possible to view information about allocated and free disk space for each Disk Data table or table partition using the *Note `ndb_desc': mysql-cluster-programs-ndb-desc. utility. For more information, see *Note mysql-cluster-programs-ndb-desc::.  File: manual.info, Node: mysql-cluster-disk-data-symlinks, Next: mysql-cluster-disk-data-storage-requirements, Prev: mysql-cluster-disk-data-objects, Up: mysql-cluster-disk-data 17.5.11.2 Using Symbolic Links with Disk Data Objects ..................................................... The performance of a MySQL Cluster that uses Disk Data storage can be greatly improved by separating data node file systems from undo log files and tablespace data files and placing these on different disks. Previous to MySQL Cluster NDB 6.2.17, MySQL Cluster NDB 6.3.22, and MySQL Cluster NDB 6.4.3, there was no direct support for this in MySQL Cluster, but it was possible to achieve this separation using symbolic links as described in this section. Beginning with MySQL Cluster NDB 6.2.17, MySQL Cluster NDB 6.3.22, and MySQL Cluster NDB 6.4.3, the data node configuration parameters `FileSystemPathDD', `FileSystemPathDataFiles', and `FileSystemPathUndoFiles' make the use of symbolic links for this purpose unnecessary. For information about these parameters, see *Note mysql-cluster-ndbd-disk-data-filesystem-parameters::. Each data node in the cluster creates a file system in the directory named `ndb_NODE_ID_fs' under the data node's `DataDir' as defined in the `config.ini' file. In this example, we assume that each data node host has 3 disks, aliased as `/data0', `/data1', and `/data2', and that the cluster's `config.ini' includes the following: [ndbd default] DataDir= /data0 Our objective is to place all Disk Data log files in `/data1', and all Disk Data data files in `/data2', on each data node host. *Note*: In this example, we assume that the cluster's data node hosts are all using Linux operating systems. For other platforms, you may need to substitute you operating system's commands for those shown here. To accomplish this, perform the following steps: * Under the data node file system create symbolic links pointing to the other drives: shell> cd /data0/ndb_2_fs shell> ls D1 D10 D11 D2 D8 D9 LCP shell> ln -s /data0 dnlogs shell> ln -s /data1 dndata You should now have two symbolic links: shell> ls -l --hide=D* lrwxrwxrwx 1 user group 30 2007-03-19 13:58 dndata -> /data1 lrwxrwxrwx 1 user group 30 2007-03-19 13:59 dnlogs -> /data2 We show this only for the data node with node ID 2; however, you must do this for _each_ data node. * Now, in the *Note `mysql': mysql. client, create a log file group and tablespace using the symbolic links, as shown here: mysql> CREATE LOGFILE GROUP lg1 -> ADD UNDOFILE 'dnlogs/undo1.log' -> INITIAL_SIZE 150M -> UNDO_BUFFER_SIZE = 1M -> ENGINE=NDBCLUSTER; mysql> CREATE TABLESPACE ts1 -> ADD DATAFILE 'dndata/data1.log' -> USE LOGFILE GROUP lg1 -> INITIAL_SIZE 1G -> ENGINE=NDBCLUSTER; Verify that the files were created and placed correctly as shown here: shell> cd /data1 shell> ls -l total 2099304 -rw-rw-r-- 1 user group 157286400 2007-03-19 14:02 undo1.dat shell> cd /data2 shell> ls -l total 2099304 -rw-rw-r-- 1 user group 1073741824 2007-03-19 14:02 data1.dat * If you are running multiple data nodes on one host, you must take care to avoid having them try to use the same space for Disk Data files. You can make this easier by creating a symbolic link in each data node file system. Suppose you are using `/data0' for both data node file systems, but you wish to have the Disk Data files for both nodes on `/data1'. In this case, you can do something similar to what is shown here: shell> cd /data0 shell> ln -s /data1/dn2 ndb_2_fs/dd shell> ln -s /data1/dn3 ndb_3_fs/dd shell> ls -l --hide=D* ndb_2_fs lrwxrwxrwx 1 user group 30 2007-03-19 14:22 dd -> /data1/dn2 shell> ls -l --hide=D* ndb_3_fs lrwxrwxrwx 1 user group 30 2007-03-19 14:22 dd -> /data1/dn3 * Now you can create a logfile group and tablespace using the symbolic link, like this: mysql> CREATE LOGFILE GROUP lg1 -> ADD UNDOFILE 'dd/undo1.log' -> INITIAL_SIZE 150M -> UNDO_BUFFER_SIZE = 1M -> ENGINE=NDBCLUSTER; mysql> CREATE TABLESPACE ts1 -> ADD DATAFILE 'dd/data1.log' -> USE LOGFILE GROUP lg1 -> INITIAL_SIZE 1G -> ENGINE=NDBCLUSTER; Verify that the files were created and placed correctly as shown here: shell> cd /data1 shell> ls dn2 dn3 shell> ls dn2 undo1.log data1.log shell> ls dn3 undo1.log data1.log  File: manual.info, Node: mysql-cluster-disk-data-storage-requirements, Prev: mysql-cluster-disk-data-symlinks, Up: mysql-cluster-disk-data 17.5.11.3 MySQL Cluster Disk Data Storage Requirements ...................................................... The following items apply to Disk Data storage requirements: * Variable-length columns of Disk Data tables take up a fixed amount of space. For each row, this is equal to the space required to store the largest possible value for that column. For general information about calculating these values, see *Note storage-requirements::. You can obtain an estimate the amount of space available in data files and undo log files by querying the *Note `INFORMATION_SCHEMA.FILES': files-table. table. For more information and examples, see *Note files-table::. *Note*: The *Note `OPTIMIZE TABLE': optimize-table. statement does not have any effect on Disk Data tables. * In a Disk Data table, the first 256 bytes of a *Note `TEXT': blob. or *Note `BLOB': blob. column are stored in memory; only the remainder is stored on disk. * Each row in a Disk Data table uses 8 bytes in memory to point to the data stored on disk. This means that, in some cases, converting an in-memory column to the disk-based format can actually result in greater memory usage. For example, convering a `CHAR(4)' column from memory-based to disk-based format increases the amount of `DataMemory' used per row from 4 to 8 bytes. *Important*: Starting the cluster with the `--initial' option does _not_ remove Disk Data files. You must remove these manually prior to performing an initial restart of the cluster. Performance of Disk Data tables can be improved by minimizing the number of disk seeks by making sure that `DiskPageBufferMemory' is of sufficient size. You can query the *Note `diskpagebuffer': mysql-cluster-ndbinfo-diskpagebuffer. table to help determine whether the value for this parameter needs to be increased.  File: manual.info, Node: mysql-cluster-online-add-node, Next: mysql-cluster-privilege-distribution, Prev: mysql-cluster-disk-data, Up: mysql-cluster-management 17.5.12 Adding MySQL Cluster Data Nodes Online ---------------------------------------------- * Menu: * mysql-cluster-online-add-node-remarks:: Adding MySQL Cluster Data Nodes Online: General Issues * mysql-cluster-online-add-node-basics:: Adding MySQL Cluster Data Nodes Online: Basic procedure * mysql-cluster-online-add-node-example:: Adding MySQL Cluster Data Nodes Online: Detailed Example This section describes how to add MySQL Cluster data nodes `online'--that is, without needing to shut down the cluster completely and restart it as part of the process. This capability is available in MySQL Cluster NDB 7.0 (beginning with MySQL Cluster NDB 6.4.0) and later MySQL Cluster release series. *Important*: Currently, you must add new data nodes to a MySQL Cluster as part of a new node group. In addition, it is not possible to change the number of replicas (or the number of nodes per node group) online.  File: manual.info, Node: mysql-cluster-online-add-node-remarks, Next: mysql-cluster-online-add-node-basics, Prev: mysql-cluster-online-add-node, Up: mysql-cluster-online-add-node 17.5.12.1 Adding MySQL Cluster Data Nodes Online: General Issues ................................................................ This section provides general information about the behavior of and current limitations in adding MySQL Cluster nodes online. Redistribution of Data The ability to add new nodes online includes a means to reorganize *Note `NDBCLUSTER': mysql-cluster. table data and indexes so that they are distributed across all data nodes, including the new ones. Table reorganization of both in-memory and Disk Data tables is supported. This redistribution does not currently include unique indexes (only ordered indexes are redistributed) or `BLOB' table data. The redistribution for *Note `NDBCLUSTER': mysql-cluster. tables already existing before the new data nodes were added is not automatic, but can be accomplished using simple SQL statements in *Note `mysql': mysql. or another MySQL client application. However, all data and indexes added to tables created after a new node group has been added are distributed automatically among all cluster data nodes, including those added as part of the new node group. Partial starts It is possible to add a new node group without all of the new data nodes being started. It is also possible to add a new node group to a degraded cluster--that is, a cluster that is only partially started, or where one or more data nodes are not running. In the latter case, the cluster must have enough nodes running to be viable before the new node group can be added. Effects on ongoing operations Normal DML operations using MySQL Cluster data are not prevented by the creation or addition of a new node group, or by table reorganization. However, it is not possible to perform DDL concurrently with table reorganization--that is, no other DDL statements can be issued while an *Note `ALTER TABLE ... REORGANIZE PARTITION': alter-table. statement is executing. In addition, during the execution of `ALTER TABLE ... REORGANIZE PARTITION' (or the execution of any other DDL statement), it is not possible to restart cluster data nodes. Failure handling Failures of data nodes during node group creation and table reorganization are handled as hown in the following table: Failure occurs Failure occurs in: during: `Old' data nodes `New' data nodes System Node group * If a node * If a node * If the creation other than other than execution of the master the master `CREATE fails: fails: NODEGROUP' has reached The creation The creation the internal of the node of the node commit point: group is group is always rolled always rolled When forward. forward. restarted, the cluster * If the * If the includes the master fails: master fails: new node group. * If the * If the Otherwise it internal internal without. commit commit point point * If the has has execution of been been `CREATE reached: reached: NODEGROUP' has not yet The The reached the creation creation internal of the of the commit point: node node group group When is is restarted, rolled rolled the cluster forward. forward. does not include the * If the * If the new node internal internal group. commit commit point point has not has not yet yet been been reached reached The The creation creation of the of the node node group group is is rolled rolled back back Table * If a node * If a node * If the reorganization other than other than execution of the master the master an `ALTER fails: fails: ONLINE TABLE TABLE The table The table REORGANIZE reorganization reorganization PARTITION' is always is always statement rolled rolled has reached forward. forward. the internal commit point: * If the * If the master fails: master fails: When the cluster is * If the * If the restarted, internal internal the data and commit commit indexes point point belonging to has has TABLE are been been distributed reached: reached: using the `new' data The The nodes. table table reorganization reorganization * If the is is execution of rolled rolled an `ALTER forward. forward. ONLINE TABLE TABLE * If the * If the REORGANIZE internal internal PARTITION' commit commit statement point point has not yet has not has not reached the yet yet internal been been commit point: reached reached When the The The cluster is table table restarted, reorganization reorganization the data and is is indexes rolled rolled belonging to back. back. TABLE are distributed using only the `old' data nodes. Dropping node groups The *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client supports a `DROP NODEGROUP' command, but it is possible to drop a node group only when no data nodes in the node group contain any data. Since there is currently no way to `empty' a specific data node or node group, this command works only the following two cases: 1. After issuing `CREATE NODEGROUP' in the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client, but before issuing any *Note `ALTER ONLINE TABLE ... REORGANIZE PARTITION': alter-table. statements in the *Note `mysql': mysql. client. 2. After dropping all *Note `NDBCLUSTER': mysql-cluster. tables using *Note `DROP TABLE': drop-table. *Note `TRUNCATE TABLE': truncate-table. does not work for this purpose because the data nodes continue to store the table definitions.  File: manual.info, Node: mysql-cluster-online-add-node-basics, Next: mysql-cluster-online-add-node-example, Prev: mysql-cluster-online-add-node-remarks, Up: mysql-cluster-online-add-node 17.5.12.2 Adding MySQL Cluster Data Nodes Online: Basic procedure ................................................................. In this section, we list the basic steps required to add new data nodes to a MySQL Cluster. For a detailed example, see *Note mysql-cluster-online-add-node-example::. *Note*: Beginning with MySQL Cluster NDB 7.0.4, this procedure applies whether you are using *Note `ndbd': mysql-cluster-programs-ndbd. or *Note `ndbmtd': mysql-cluster-programs-ndbmtd. binaries for the data node processes. Previously, this did not work with multi-threaded data nodes. (Bug#43108) Assuming that you already have a running MySQL Cluster, adding data nodes online requires the following steps: 1. Edit the cluster configuration `config.ini' file, adding new `[ndbd]' sections corresponding to the nodes to be added. In the case where the cluster uses multiple management servers, these changes need to be made to all `config.ini' files used by the management servers. You must be careful that node IDs for any new data nodes added in the `config.ini' file do not overlap node IDs used by existing nodes. In the event that you have API nodes using dynamically allocated node IDs and these IDs match node IDs that you want to use for new data nodes, it is possible to force any such API nodes to `migrate', as described later in this procedure. 2. Perform a rolling restart of all MySQL Cluster management servers. *Important*: All management servers must be restarted with the `--reload' or `--initial' option to force the reading of the new configuration. 3. Perform a rolling restart of all existing MySQL Cluster data nodes. It is not necessary (or usually even desirable) to use `--initial' when restarting the existing data nodes. If you are using API nodes with dynamically allocated IDs matching any node IDs that you wish to assign to new data nodes, you must restart all API nodes (including SQL nodes) before restarting any of the data nodes processes in this step. This causes any API nodes with node IDs that were previously not explicitly assigned to relinquish those node IDs and acquire new ones. 4. Perform a rolling restart of any SQL or API nodes connected to the MySQL Cluster. 5. Perform an initial start of the new data nodes. *Note*: The new data nodes may be started in any order, and can also be started concurrently, as long as they are started after the rolling restarts of all existing nodes have been completed and before proceeding to the next step. 6. Execute one or more `CREATE NODEGROUP' commands in the MySQL Cluster management client to create the new node group or node groups to which the new data nodes will belong. 7. Redistribute the cluster's data among all data nodes (including the new ones) by issuing an *Note `ALTER ONLINE TABLE ... REORGANIZE PARTITION': alter-table. statement in the *Note `mysql': mysql. client for each *Note `NDBCLUSTER': mysql-cluster. table. *Note*: This needs to be done only for tables already existing at the time the new node group is added. Data in tables created after the new node group is added is distributed automatically; however, data added to any given table `tbl' that existed before the new nodes were added is not distributed using the new nodes until that table has been reorganized using *Note `ALTER ONLINE TABLE tbl REORGANIZE PARTITION': alter-table. 8. Reclaim the space freed on the `old' nodes by issuing, for each *Note `NDBCLUSTER': mysql-cluster. table, an *Note `OPTIMIZE TABLE': optimize-table. statement in the *Note `mysql': mysql. client. You can add all the nodes desired, then issue several `CREATE NODEGROUP' commands in succession to add the new node groups to the cluster. Prior to MySQL Cluster NDB 7.0.16 and MySQL Cluster NDB 7.1.5, when adding multiple new node groups to a MySQL Cluster, it was necessary to add only the nodes to be assigned to a given new node group, create that node group using `CREATE NODEGROUP', then repeat this process for each new node group to be added to the cluster. (Bug#54497)  File: manual.info, Node: mysql-cluster-online-add-node-example, Prev: mysql-cluster-online-add-node-basics, Up: mysql-cluster-online-add-node 17.5.12.3 Adding MySQL Cluster Data Nodes Online: Detailed Example .................................................................. In this section we provide a detailed example illustrating how to add new MySQL Cluster data nodes online, starting with a MySQL Cluster having 2 data nodes in a single node group and concluding with a cluster having 4 data nodes in 2 node groups. Starting configuration For purposes of illustration, we assume a minimal configuration, and that the cluster uses a `config.ini' file containing only the following information: [ndbd default] DataMemory = 100M IndexMemory = 100M NoOfReplicas = 2 DataDir = /usr/local/mysql/var/mysql-cluster [ndbd] Id = 1 HostName = 192.168.0.1 [ndbd] Id = 2 HostName = 192.168.0.2 [mgm] HostName = 192.168.0.10 Id = 10 [api] Id=20 HostName = 192.168.0.20 [api] Id=21 HostName = 192.168.0.21 *Note*: We have left a gap in the sequence between data node IDs and other nodes. This make it easier later to assign node IDs that are not already in use to data nodes which are newly added. We also assume that you have already started the cluster using the appropriate command line or `my.cnf' options, and that running `SHOW' in the management client produces output similar to what is shown here: -- NDB Cluster -- Management Client -- ndb_mgm> SHOW Connected to Management Server at: 192.168.0.10:1186 Cluster Configuration --------------------- [ndbd(NDB)] 2 node(s) id=1 @192.168.0.1 (5.1.56-ndb-7.1.16, Nodegroup: 0, Master) id=2 @192.168.0.2 (5.1.56-ndb-7.1.16, Nodegroup: 0) [ndb_mgmd(MGM)] 1 node(s) id=10 @192.168.0.10 (5.1.56-ndb-7.1.16) [mysqld(API)] 2 node(s) id=20 @192.168.0.20 (5.1.56-ndb-7.1.16) id=21 @192.168.0.21 (5.1.56-ndb-7.1.16) Finally, we assume that the cluster contains a single *Note `NDBCLUSTER': mysql-cluster. table created as shown here: USE n; CREATE TABLE ips ( id BIGINT NOT NULL AUTO_INCREMENT PRIMARY KEY, country_code CHAR(2) NOT NULL, type CHAR(4) NOT NULL, ip_address varchar(15) NOT NULL, addresses BIGINT UNSIGNED DEFAULT NULL, date BIGINT UNSIGNED DEFAULT NULL ) ENGINE NDBCLUSTER; The memory usage and related information shown later in this section was generated after inserting approximately 50000 rows into this table. *Note*: In this example, we show the single-threaded *Note `ndbd': mysql-cluster-programs-ndbd. being used for the data node processes. However--beginning with MySQL Cluster NDB 7.0.4--you can also apply this example, if you are using the multi-threaded *Note `ndbmtd': mysql-cluster-programs-ndbmtd. by substituting *Note `ndbmtd': mysql-cluster-programs-ndbmtd. for *Note `ndbd': mysql-cluster-programs-ndbd. wherever it appears in the steps that follow. (Bug#43108) Step 1: Update configuration file Open the cluster global configuration file in a text editor and add `[ndbd]' sections corresponding to the 2 new data nodes. (We give these data nodes IDs 3 and 4, and assume that they are to be run on host machines at addresses 192.168.0.3 and 192.168.0.4, respectively.) After you have added the new sections, the contents of the `config.ini' file should look like what is shown here, where the additions to the file are shown in bold type: [ndbd default] DataMemory = 100M IndexMemory = 100M NoOfReplicas = 2 DataDir = /usr/local/mysql/var/mysql-cluster [ndbd] Id = 1 HostName = 192.168.0.1 [ndbd] Id = 2 HostName = 192.168.0.2 *[ndbd] Id = 3 HostName = 192.168.0.3 [ndbd] Id = 4 HostName = 192.168.0.4* [mgm] HostName = 192.168.0.10 Id = 10 [api] Id=20 HostName = 192.168.0.20 [api] Id=21 HostName = 192.168.0.21 Once you have made the necessary changes, save the file. Step 2: Restart the management server Restarting the cluster management server requires that you issue separate commands to stop the management server and then to start it again, as follows: 1. Stop the management server using the management client `STOP' command, as shown here: ndb_mgm> 10 STOP Node 10 has shut down. Disconnecting to allow Management Server to shutdown shell> 2. Because shutting down the management server causes the management client to terminate, you must start the management server from the system shell. For simplicity, we assume that `config.ini' is in the same directory as the management server binary, but in practice, you must supply the correct path to the configuration file. You must also supply the `--reload' or `--initial' option so that the management server reads the new configuration from the file rather than its configuration cache. If your shell's current directory is also the same as the directory where the management server binary is located, then you can invoke the management server as shown here: shell> ndb_mgmd -f config.ini --reload 2008-12-08 17:29:23 [MgmSrvr] INFO -- NDB Cluster Management Server. 5.1.56-ndb-7.1.16 2008-12-08 17:29:23 [MgmSrvr] INFO -- Reading cluster configuration from 'config.ini' If you check the output of `SHOW' in the management client after restarting the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. process, you should now see something like this: -- NDB Cluster -- Management Client -- ndb_mgm> SHOW Connected to Management Server at: 192.168.0.10:1186 Cluster Configuration --------------------- [ndbd(NDB)] 2 node(s) id=1 @192.168.0.1 (5.1.56-ndb-7.1.16, Nodegroup: 0, Master) id=2 @192.168.0.2 (5.1.56-ndb-7.1.16, Nodegroup: 0) id=3 (not connected, accepting connect from 192.168.0.3) id=4 (not connected, accepting connect from 192.168.0.4) [ndb_mgmd(MGM)] 1 node(s) id=10 @192.168.0.10 (5.1.56-ndb-7.1.16) [mysqld(API)] 2 node(s) id=20 @192.168.0.20 (5.1.56-ndb-7.1.16) id=21 @192.168.0.21 (5.1.56-ndb-7.1.16) Step 3: Perform a rolling restart of the existing data nodes This step can be accomplished entirely within the cluster management client using the `RESTART' command, as shown here: ndb_mgm> 1 RESTART Node 1: Node shutdown initiated Node 1: Node shutdown completed, restarting, no start. Node 1 is being restarted ndb_mgm> Node 1: Start initiated (version 7.1.16) Node 1: Started (version 7.1.16) ndb_mgm> 2 RESTART Node 2: Node shutdown initiated Node 2: Node shutdown completed, restarting, no start. Node 2 is being restarted ndb_mgm> Node 2: Start initiated (version 7.1.16) ndb_mgm> Node 2: Started (version 7.1.16) *Important*: After issuing each `X RESTART' command, wait until the management client reports `Node X: Started (version ...)' _before_ proceeding any further. Beginning with MySQL Cluster NDB 7.0.24 and MySQL Cluster NDB 7.1.13, you can verify that all existing data nodes were restarted using the updated configuration by checking the *Note `ndbinfo.nodes': mysql-cluster-ndbinfo-nodes. table in the *Note `mysql': mysql. client. Step 4: Perform a rolling restart of all cluster API nodes Shut down and restart each MySQL server acting as an SQL node in the cluster using *Note `mysqladmin shutdown': mysqladmin. followed by *Note `mysqld_safe': mysqld-safe. (or another startup script). This should be similar to what is shown here, where PASSWORD is the MySQL `root' password for a given MySQL server instance: shell> mysqladmin -uroot -pPASSWORD shutdown 081208 20:19:56 mysqld_safe mysqld from pid file /usr/local/mysql/var/tonfisk.pid ended shell> mysqld_safe --ndbcluster --ndb-connectstring=192.168.0.10 & 081208 20:20:06 mysqld_safe Logging to '/usr/local/mysql/var/tonfisk.err'. 081208 20:20:06 mysqld_safe Starting mysqld daemon with databases from /usr/local/mysql/var Of course, the exact input and output depend on how and where MySQL is installed on the system, as well as which options you choose to start it (and whether or not some or all of these options are specified in a `my.cnf' file). Step 5: Perform an initial start of the new data nodes From a system shell on each of the hosts for the new data nodes, start the data nodes as shown here, using the `--initial' option: shell> ndbd -c 192.168.0.10 --initial *Note*: Unlike the case with restarting the existing data nodes, you can start the new data nodes concurrently; you do not need to wait for one to finish starting before starting the other. _Wait until both of the new data nodes have started before proceeding with the next step_. Once the new data nodes have started, you can see in the output of the management client `SHOW' command that they do not yet belong to any node group (as indicated with bold type here): ndb_mgm> SHOW Connected to Management Server at: 192.168.0.10:1186 Cluster Configuration --------------------- [ndbd(NDB)] 2 node(s) id=1 @192.168.0.1 (5.1.56-ndb-7.1.16, Nodegroup: 0, Master) id=2 @192.168.0.2 (5.1.56-ndb-7.1.16, Nodegroup: 0) id=3 @192.168.0.3 (5.1.56-ndb-7.1.16, *no nodegroup*) id=4 @192.168.0.4 (5.1.56-ndb-7.1.16, *no nodegroup*) [ndb_mgmd(MGM)] 1 node(s) id=10 @192.168.0.10 (5.1.56-ndb-7.1.16) [mysqld(API)] 2 node(s) id=20 @192.168.0.20 (5.1.56-ndb-7.1.16) id=21 @192.168.0.21 (5.1.56-ndb-7.1.16) Step 6: Create a new node group You can do this by issuing a `CREATE NODEGROUP' command in the cluster management client. This command takes as its argument a comma-separated list of the node IDs of the data nodes to be included in the new node group, as shown here: ndb_mgm> CREATE NODEGROUP 3,4 Nodegroup 1 created By issuing `SHOW' again, you can verify that data nodes 3 and 4 have joined the new node group (again indicated in bold type): ndb_mgm> SHOW Connected to Management Server at: 192.168.0.10:1186 Cluster Configuration --------------------- [ndbd(NDB)] 2 node(s) id=1 @192.168.0.1 (5.1.56-ndb-7.1.16, Nodegroup: 0, Master) id=2 @192.168.0.2 (5.1.56-ndb-7.1.16, Nodegroup: 0) id=3 @192.168.0.3 (5.1.56-ndb-7.1.16, *Nodegroup: 1*) id=4 @192.168.0.4 (5.1.56-ndb-7.1.16, *Nodegroup: 1*) [ndb_mgmd(MGM)] 1 node(s) id=10 @192.168.0.10 (5.1.56-ndb-7.1.16) [mysqld(API)] 2 node(s) id=20 @192.168.0.20 (5.1.56-ndb-7.1.16) id=21 @192.168.0.21 (5.1.56-ndb-7.1.16) Step 7: Redistribute cluster data When a node group is created, existing data and indexes are not automatically distributed to the new node group's data nodes, as you can see by issuing the appropriate `REPORT' command in the management client: ndb_mgm> ALL REPORT MEMORY Node 1: Data usage is 5%(177 32K pages of total 3200) Node 1: Index usage is 0%(108 8K pages of total 12832) Node 2: Data usage is 5%(177 32K pages of total 3200) Node 2: Index usage is 0%(108 8K pages of total 12832) *Node 3: Data usage is 0%(0 32K pages of total 3200) Node 3: Index usage is 0%(0 8K pages of total 12832) Node 4: Data usage is 0%(0 32K pages of total 3200) Node 4: Index usage is 0%(0 8K pages of total 12832)* By using *Note `ndb_desc': mysql-cluster-programs-ndb-desc. with the `-p' option, which causes the output to include partitioning information, you can see that the table still uses only 2 partitions (in the `Per partition info' section of the output, shown here in bold text): shell> ndb_desc -c 192.168.0.10 -d n ips -p -- ips -- Version: 1 Fragment type: 9 K Value: 6 Min load factor: 78 Max load factor: 80 Temporary table: no Number of attributes: 6 Number of primary keys: 1 Length of frm data: 340 Row Checksum: 1 Row GCI: 1 SingleUserMode: 0 ForceVarPart: 1 FragmentCount: 2 TableStatus: Retrieved -- Attributes -- id Bigint PRIMARY KEY DISTRIBUTION KEY AT=FIXED ST=MEMORY AUTO_INCR country_code Char(2;latin1_swedish_ci) NOT NULL AT=FIXED ST=MEMORY type Char(4;latin1_swedish_ci) NOT NULL AT=FIXED ST=MEMORY ip_address Varchar(15;latin1_swedish_ci) NOT NULL AT=SHORT_VAR ST=MEMORY addresses Bigunsigned NULL AT=FIXED ST=MEMORY date Bigunsigned NULL AT=FIXED ST=MEMORY -- Indexes -- PRIMARY KEY(id) - UniqueHashIndex PRIMARY(id) - OrderedIndex *-- Per partition info -- Partition Row count Commit count Frag fixed memory Frag varsized memory 0 26086 26086 1572864 557056 1 26329 26329 1605632 557056* NDBT_ProgramExit: 0 - OK You can cause the data to be redistributed among all of the data nodes by performing, for each *Note `NDBCLUSTER': mysql-cluster. table, an *Note `ALTER ONLINE TABLE ... REORGANIZE PARTITION': alter-table. statement in the *Note `mysql': mysql. client. After issuing the statement `ALTER ONLINE TABLE ips REORGANIZE PARTITION', you can see using *Note `ndb_desc': mysql-cluster-programs-ndb-desc. that the data for this table is now stored using 4 partitions, as shown here (with the relevant portions of the output in bold type): shell> ndb_desc -c 192.168.0.10 -d n ips -p -- ips -- Version: 16777217 Fragment type: 9 K Value: 6 Min load factor: 78 Max load factor: 80 Temporary table: no Number of attributes: 6 Number of primary keys: 1 Length of frm data: 341 Row Checksum: 1 Row GCI: 1 SingleUserMode: 0 ForceVarPart: 1 FragmentCount: 4 TableStatus: Retrieved -- Attributes -- id Bigint PRIMARY KEY DISTRIBUTION KEY AT=FIXED ST=MEMORY AUTO_INCR country_code Char(2;latin1_swedish_ci) NOT NULL AT=FIXED ST=MEMORY type Char(4;latin1_swedish_ci) NOT NULL AT=FIXED ST=MEMORY ip_address Varchar(15;latin1_swedish_ci) NOT NULL AT=SHORT_VAR ST=MEMORY addresses Bigunsigned NULL AT=FIXED ST=MEMORY date Bigunsigned NULL AT=FIXED ST=MEMORY -- Indexes -- PRIMARY KEY(id) - UniqueHashIndex PRIMARY(id) - OrderedIndex *-- Per partition info -- Partition Row count Commit count Frag fixed memory Frag varsized memory 0 12981 52296 1572864 557056 1 13236 52515 1605632 557056 2 13105 13105 819200 294912 3 13093 13093 819200 294912* NDBT_ProgramExit: 0 - OK *Note*: Normally, *Note `ALTER [ONLINE] TABLE TABLE_NAME REORGANIZE PARTITION': alter-table. is used with a list of partition identifiers and a set of partition definitions to create a new partitioning scheme for a table that has already been explicitly partitioned. Its use here to redistribute data onto a new MySQL Cluster node group is an exception in this regard; when used in this way, only the name of the table is used following the `TABLE' keyword, and no other keywords or identifiers follow `REORGANIZE PARTITION'. Prior to MySQL Cluster NDB 6.4.3, *Note `ALTER ONLINE TABLE ... REORGANIZE PARTITION': alter-table. with no `PARTITION_NAMES INTO (PARTITION_DEFINITIONS)' option did not work correctly with Disk Data tables or with in-memory *Note `NDBCLUSTER': mysql-cluster. tables having one or more disk-based columns. (Bug#42549) For more information, see *Note alter-table::. In addition, for each table, the *Note `ALTER ONLINE TABLE': alter-table. statement should be followed by an *Note `OPTIMIZE TABLE': optimize-table. to reclaim wasted space. You can obtain a list of all *Note `NDBCLUSTER': mysql-cluster. tables using the following query against the *Note `INFORMATION_SCHEMA.TABLES': tables-table. table: SELECT TABLE_SCHEMA, TABLE_NAME FROM INFORMATION_SCHEMA.TABLES WHERE ENGINE = 'NDBCLUSTER'; *Note*: The `INFORMATION_SCHEMA.TABLES.ENGINE' value for a MySQL Cluster table is always *Note `NDBCLUSTER': mysql-cluster, regardless of whether the `CREATE TABLE' statement used to create the table (or *Note `ALTER TABLE': alter-table. statement used to convert an existing table from a different storage engine) used *Note `NDB': mysql-cluster. or *Note `NDBCLUSTER': mysql-cluster. in its `ENGINE' option. You can see after performing these statements in the output of `ALL REPORT MEMORY' that the data and indexes are now redistributed between all cluster data nodes, as shown here: ndb_mgm> ALL REPORT MEMORY Node 1: Data usage is 5%(176 32K pages of total 3200) Node 1: Index usage is 0%(76 8K pages of total 12832) Node 2: Data usage is 5%(176 32K pages of total 3200) Node 2: Index usage is 0%(76 8K pages of total 12832) Node 3: Data usage is 2%(80 32K pages of total 3200) Node 3: Index usage is 0%(51 8K pages of total 12832) Node 4: Data usage is 2%(80 32K pages of total 3200) Node 4: Index usage is 0%(50 8K pages of total 12832) *Note*: Since only one DDL operation on *Note `NDBCLUSTER': mysql-cluster. tables can be executed at a time, you must wait for each *Note `ALTER ONLINE TABLE ... REORGANIZE PARTITION': alter-table. statement to finish before issuing the next one. It is not necessary to issue *Note `ALTER ONLINE TABLE ... REORGANIZE PARTITION': alter-table. statements for *Note `NDBCLUSTER': mysql-cluster. tables created _after_ the new data nodes have been added; data added to such tables is distributed among all data nodes automatically. However, in *Note `NDBCLUSTER': mysql-cluster. tables that existed _prior to_ the addition of the new nodes, neither existing nor new data is distributed using the new nodes until these tables have been reorganized using *Note `ALTER ONLINE TABLE ... REORGANIZE PARTITION': alter-table. Alternative procedure, without rolling restart It is possible to avoid the need for a rolling restart by configuring the extra data nodes, but not starting them, when first starting the cluster. We assume, as before, that you wish to start with two data nodes--nodes 1 and 2--in one node group and later to expand the cluster to four data nodes, by adding a second node group consisting of nodes 3 and 4: [ndbd default] DataMemory = 100M IndexMemory = 100M NoOfReplicas = 2 DataDir = /usr/local/mysql/var/mysql-cluster [ndbd] Id = 1 HostName = 192.168.0.1 [ndbd] Id = 2 HostName = 192.168.0.2 [ndbd] Id = 3 HostName = 192.168.0.3 Nodegroup = 65536 # MySQL Cluster NDB 7.0.24 and later; # MySQL Cluster NDB 7.1.13 and later [ndbd] Id = 4 HostName = 192.168.0.4 Nodegroup = 65536 # MySQL Cluster NDB 7.0.24 and later; # MySQL Cluster NDB 7.1.13 and later [mgm] HostName = 192.168.0.10 Id = 10 [api] Id=20 HostName = 192.168.0.20 [api] Id=21 HostName = 192.168.0.21 Prior to MySQL Cluster NDB 7.0.24 and MySQL Cluster NDB 7.1.13, you must perform the initial start of the cluster using the `--nowait-nodes' option with *Note `ndbd': mysql-cluster-programs-ndbd. (or *Note `ndbmtd': mysql-cluster-programs-ndbmtd. in MySQL Cluster NDB 7.0.4 and later) for each of the data nodes that you wish to have online immediately, so that the cluster does not wait for the remaining nodes to start: shell> ndbd -c 192.168.0.10 --initial --nowait-nodes=3,4 Beginning with MySQL Cluster NDB 7.0.24 and MySQL Cluster NDB 7.1.13, the data nodes to be brought online at a later time (nodes 3 and 4) can be configured with `NodeGroup = 65536', in which case it is not necessary to start the nodes to be started immediately (nodes 1 and 2) with the `--nowait-nodes' option, so nodes 1 and 2 can each be started as shown here: shell> ndbd -c 192.168.0.10 --initial The data nodes configured with `NodeGroup = 65536' are treated by the management server as though you had started nodes 1 and 2 using `--nowait-nodes=3,4' after waiting for a period of time determined by the setting for the `StartNoNodeGroupTimeout' data node configuration parameter (also introduced in MySQL Cluster NDB 7.0.24 and MySQL Cluster NDB 7.1.13). By default, this is 15 seconds (15000 milliseconds). *Note*: `StartNoNodegroupTimeout' must be the same for all data nodes in the cluster; for this reason, you should always set it in the `[ndbd default]' section of the `config.ini' file, rather than for individual data nodes. When you are ready to add the second node group, you need only perform the following additional steps: 1. Start data nodes 3 and 4, invoking the data node process once for each new node: shell> ndbd -c 192.168.0.10 --initial 2. Issue the appropriate `CREATE NODEGROUP' command in the management client: ndb_mgm> CREATE NODEGROUP 3,4 3. In the *Note `mysql': mysql. client, issue *Note `ALTER ONLINE TABLE ... REORGANIZE PARTITION': alter-table. and *Note `OPTIMIZE TABLE': optimize-table. statements for each existing *Note `NDBCLUSTER': mysql-cluster. table. (As noted elsewhere in this section, existing MySQL Cluster tables cannot use the new nodes for data distribution until this has been done.)  File: manual.info, Node: mysql-cluster-privilege-distribution, Prev: mysql-cluster-online-add-node, Up: mysql-cluster-management 17.5.13 Distributed MySQL Privileges for MySQL Cluster ------------------------------------------------------ MySQL Cluster NDB 7.2 introduces support for distributing MySQL users and privileges across all SQL nodes in a MySQL Cluster. This support is not enabled by default; you should follow the procedure outlined in this section in order to do so. Normally, each MySQL server's user privilege tables in the `mysql' database must use the *Note `MyISAM': myisam-storage-engine. storage engine, which means that a user account and its associated privileges created on one SQL node are not available on the cluster's other SQL nodes. In MySQL Cluster NDB 7.2 and later, an SQL file `ndb_dist_priv.sql' is provided with the MySQL Cluster distribution. This file can be found in the `share/mysql' directory in the MySQL installation directory. The first step in enabling distributed privileges is to load this script into a MySQL Server that functions as an SQL node (which we refer to after this as the _target_ SQL node or MySQL Server). You can do this by executing the following command from the system shell on the target SQL node after changing to its MySQL installation directory (where OPTIONS stands for any additional options needed to connect to this SQL node): shell> mysql OPTIONS -uroot < share/mysql/ndb_dist_priv.sql Importing `ndb_dist_priv.sql' creates a number of stored routines (six stored procedures and one stored function) in the `mysql' database on the target SQL node. After connecting to the SQL node in the mysql client (as MySQL `root'), you can verify that these were created as shown here: mysql> SELECT ROUTINE_NAME, ROUTINE_SCHEMA, ROUTINE_TYPE -> FROM INFORMATION_SCHEMA.ROUTINES -> WHERE ROUTINE_NAME LIKE 'mysql_cluster%' -> ORDER BY ROUTINE_TYPE; +---------------------------------------------+----------------+--------------+ | ROUTINE_NAME | ROUTINE_SCHEMA | ROUTINE_TYPE | +---------------------------------------------+----------------+--------------+ | mysql_cluster_privileges_are_distributed | mysql | FUNCTION | | mysql_cluster_backup_privileges | mysql | PROCEDURE | | mysql_cluster_move_grant_tables | mysql | PROCEDURE | | mysql_cluster_move_privileges | mysql | PROCEDURE | | mysql_cluster_restore_local_privileges | mysql | PROCEDURE | | mysql_cluster_restore_privileges | mysql | PROCEDURE | | mysql_cluster_restore_privileges_from_local | mysql | PROCEDURE | +---------------------------------------------+----------------+--------------+ 7 rows in set (0.01 sec) The stored procedure named `mysql_cluster_move_privileges' creates backup copies of the existing privilege tables, then converts them to *Note `NDB': mysql-cluster. Two sets of copies are created in the `mysql' database: * A set of local copies that use the *Note `MyISAM': myisam-storage-engine. storage engine, and named by adding the suffix `_backup' to the original privilege table names. * A set of distributed copies (using *Note `NDBCLUSTER': mysql-cluster.). These tables are named by prefixing `ndb_' and appending `_backup' to the names of the original tables. Although the original privilege tables are backed up automatically, it is always a good idea to create backups manually of the existing privilege tables on all affected SQL nodes before proceeding. You can do this using *Note `mysqldump': mysqldump. in a manner similar to what is shown here: shell> mysqldump OPTIONS -uroot \ mysql user db tables_priv columns_priv procs_priv > BACKUP_FILE To perform the conversion, you must be connected to the target SQL node using the *Note `mysql': mysql. client (again, as the MySQL `root' user). Invoke the stored procedure like this: mysql> CALL mysql_cluster_move_privileges(); Query OK, 0 rows affected (22.32 sec) Depending on the number of rows in the privilege tables, this procedure may take some time to execute. If some of the privilege tables are empty, you may see one or more `No data - zero rows fetched, selected, or processed' warnings when `mysql_cluster_move_privileges' returns. In such cases, the warnings may be safely ignored. To verify that the conversion was successful, you can use the stored function `mysql_cluster_privileges_are_distributed' as shown here: mysql> SELECT CONCAT( -> 'Conversion ', -> IF(mysql_cluster_privileges_are_distributed(), 'succeeded', 'failed'), -> '.') -> AS Result; +-----------------------+ | Result | +-----------------------+ | Conversion succeeded. | +-----------------------+ 1 row in set (0.00 sec) `mysql_cluster_privileges_are_distributed' checks for the existence of the distributed privilege tables and returns `1' if all of the privilege tables are distributed; otherwise, it returns `0'. You can verify that the backups have been created using a query such as this one: mysql> SELECT TABLE_NAME, ENGINE FROM INFORMATION_SCHEMA.TABLES -> WHERE TABLE_SCHEMA = 'mysql' AND TABLE_NAME LIKE '%backup' -> ORDER BY ENGINE; +-------------------------+------------+ | TABLE_NAME | ENGINE | +-------------------------+------------+ | procs_priv_backup | MyISAM | | db_backup | MyISAM | | columns_priv_backup | MyISAM | | user_backup | MyISAM | | host_backup | MyISAM | | tables_priv_backup | MyISAM | | ndb_user_backup | ndbcluster | | ndb_tables_priv_backup | ndbcluster | | ndb_procs_priv_backup | ndbcluster | | ndb_host_backup | ndbcluster | | ndb_db_backup | ndbcluster | | ndb_columns_priv_backup | ndbcluster | +-------------------------+------------+ 12 rows in set (0.00 sec) Once the conversion to distributed privileges has been made, any time a MySQL user account is created, dropped, or has its privileges updated on any SQL node, the changes take effect immediately on all other MySQL servers attached to the cluster. Once privileges are distributed, any new MySQL Servers that connect to the cluster automatically participate in the distribution. *Note*: For clients connected to SQL nodes at the time that `mysql_cluster_move_privileges' is executed, you may need to execute *Note `FLUSH PRIVILEGES': flush. on those SQL nodes, or to disconnect and then reconnect the clients, in order for those clients to be able to see the changes in privileges. All MySQL user privileges are distributed across all connected MySQL Servers. This includes privileges associated with views and stored routines. While automatic distribution of views and stored routines is not currently supported, you can attempt to distribute stored routines by issuing a statement such as *Note `ALTER TABLE mysql.proc ENGINE = NDB': alter-table, but you must verify manually that any tables referenced by the stored routines exist on all SQL nodes, since MySQL Cluster has no support at the present time for doing this automatically. There is currently no way to distribute views among MySQL Cluster SQL nodes, other than by creating them manually on each SQL node. If you do this, you must make certain that all base tables referenced by the views use the *Note `NDB': mysql-cluster. storage engine; otherwise, the views are likely to diverge very quickly. In the event that an SQL node becomes disconnected from the cluster while `mysql_cluster_move_privileges' is running, you must drop its privilege tables after reconnecting to the cluster, using a statement such as *Note `DROP TABLE IF EXISTS user db tables_priv columns_priv procs_priv': drop-table. This causes the SQL node to use the shared privilege tables rather than its own local versions of them. This is not needed when connecting a new SQL node to the cluster for the first time. In the event of an initial restart of the entire cluster (all data nodes shut down, then started again with `--initial'), the shared privilege tables are lost. In this case, you can restore them using the original target SQL node either from the backups made by `mysql_cluster_move_privileges' or from a dump file created with *Note `mysqldump': mysqldump. If you need to use a new MySQL Server to perform the restoration, you should start it with `--skip-grant-tables' when connecting to the cluster for the first time; after this, you can restore the privilege tables locally, then distribute them again using `mysql_cluster_move_privileges'. After restoring and distributing the tables, you should restart this MySQL Server without the `--skip-grant-tables' option. *Important*: Applications that access MySQL Cluster data directly, including NDB API and ClusterJ applications, are not subject to the MySQL privilege system. This means that, once you have distributed the grant tables, they can be freely accessed by such applications, just as they can any other *Note `NDB': mysql-cluster. tables. In particular, you should keep in mind that _NDB API and ClusterJ applications can read and write user names, host names, password hashes, and any other contents of the distributed grant tables without any restrictions_.  File: manual.info, Node: mysql-cluster-replication, Next: mysql-cluster-news, Prev: mysql-cluster-management, Up: mysql-cluster 17.6 MySQL Cluster Replication ============================== * Menu: * mysql-cluster-replication-abbreviations:: MySQL Cluster Replication: Abbreviations and Symbols * mysql-cluster-replication-general:: General Requirements for MySQL Cluster Replication * mysql-cluster-replication-issues:: Known Issues in MySQL Cluster Replication * mysql-cluster-replication-schema:: MySQL Cluster Replication Schema and Tables * mysql-cluster-replication-preparation:: Preparing the MySQL Cluster for Replication * mysql-cluster-replication-starting:: Starting MySQL Cluster Replication (Single Replication Channel) * mysql-cluster-replication-two-channels:: Using Two Replication Channels for MySQL Cluster Replication * mysql-cluster-replication-failover:: Implementing Failover with MySQL Cluster Replication * mysql-cluster-replication-backups:: MySQL Cluster Backups With MySQL Cluster Replication * mysql-cluster-replication-multi-master:: MySQL Cluster Replication: Multi-Master and Circular Replication * mysql-cluster-replication-conflict-resolution:: MySQL Cluster Replication Conflict Resolution Previous to MySQL 5.1.6, _asynchronous replication_, more usually referred to simply as `replication', was not available when using MySQL Cluster. MySQL 5.1.6 introduces master-slave replication of this type for MySQL Cluster databases. This section explains how to set up and manage a configuration wherein one group of computers operating as a MySQL Cluster replicates to a second computer or group of computers. We assume some familiarity on the part of the reader with standard MySQL replication as discussed elsewhere in this Manual. (See *Note replication::). Normal (non-clustered) replication involves a `master' server and a `slave' server, the master being the source of the operations and data to be replicated and the slave being the recipient of these. In MySQL Cluster, replication is conceptually very similar but can be more complex in practice, as it may be extended to cover a number of different configurations including replicating between two complete clusters. Although a MySQL Cluster itself depends on the *Note `NDB': mysql-cluster. storage engine for clustering functionality, it is not necessary to use *Note `NDB': mysql-cluster. as the storage engine for the slave's copies of the replicated tables (see *Note mysql-cluster-replication-ndb-non-ndb::). However, for maximum availability, it is possible (and preferable) to replicate from one MySQL Cluster to another, and it is this scenario that we discuss, as shown in the following figure: MySQL Cluster-to-Cluster Replication Layout In this scenario, the replication process is one in which successive states of a master cluster are logged and saved to a slave cluster. This process is accomplished by a special thread known as the NDB binlog injector thread, which runs on each MySQL server and produces a binary log (`binlog'). This thread ensures that all changes in the cluster producing the binary log--and not just those changes that are effected through the MySQL Server--are inserted into the binary log with the correct serialization order. We refer to the MySQL replication master and replication slave servers as replication servers or replication nodes, and the data flow or line of communication between them as a _replication channel_. For information about performing point-in-time recovery with MySQL Cluster and MySQL Cluster Replication, see *Note mysql-cluster-replication-pitr::. Replication from `NDB' to non-`NDB' tables It is possible to replicate *Note `NDB': mysql-cluster. tables from a MySQL Cluster acting as the master to tables using other MySQL storage engines such as *Note `InnoDB': innodb-storage-engine. or *Note `MyISAM': myisam-storage-engine. on a slave *Note `mysqld': mysqld. However, because of differences between the version of *Note `mysqld': mysqld. provided with MySQL Cluster and that included with MySQL Server 5.1, the slave server must also use a *Note `mysqld': mysqld. binary from the MySQL Cluster distribution. See *Note mysql-cluster-replication-general::.  File: manual.info, Node: mysql-cluster-replication-abbreviations, Next: mysql-cluster-replication-general, Prev: mysql-cluster-replication, Up: mysql-cluster-replication 17.6.1 MySQL Cluster Replication: Abbreviations and Symbols ----------------------------------------------------------- Throughout this section, we use the following abbreviations or symbols for referring to the master and slave clusters, and to processes and commands run on the clusters or cluster nodes: Symbol or Description (Refers to...) Abbreviation M The cluster serving as the (primary) replication master S The cluster acting as the (primary) replication slave `shellM>' Shell command to be issued on the master cluster `mysqlM>' MySQL client command issued on a single MySQL server running as an SQL node on the master cluster `mysqlM*>' MySQL client command to be issued on all SQL nodes participating in the replication master cluster `shellS>' Shell command to be issued on the slave cluster `mysqlS>' MySQL client command issued on a single MySQL server running as an SQL node on the slave cluster `mysqlS*>' MySQL client command to be issued on all SQL nodes participating in the replication slave cluster C Primary replication channel C' Secondary replication channel M' Secondary replication master S' Secondary replication slave  File: manual.info, Node: mysql-cluster-replication-general, Next: mysql-cluster-replication-issues, Prev: mysql-cluster-replication-abbreviations, Up: mysql-cluster-replication 17.6.2 General Requirements for MySQL Cluster Replication --------------------------------------------------------- A replication channel requires two MySQL servers acting as replication servers (one each for the master and slave). For example, this means that in the case of a replication setup with two replication channels (to provide an extra channel for redundancy), there will be a total of four replication nodes, two per cluster. Replication of a MySQL Cluster as described in this section and those following is dependent on row-based replication. This means that the replication master MySQL server must be started with `--binlog-format=ROW' or `--binlog-format=MIXED', as described in *Note mysql-cluster-replication-starting::. For general information about row-based replication, see *Note replication-formats::. *Important*: If you attempt to use MySQL Cluster Replication with `--binlog-format=STATEMENT', replication fails to work properly because the `ndb_binlog_index' table on the master and the `epoch' column of the `ndb_apply_status' table on the slave are not updated (see *Note mysql-cluster-replication-schema::). Instead, only updates on the MySQL server acting as the replication master propagate to the slave, and no updates from any other SQL nodes on the master cluster are replicated. In all MySQL Cluster NDB 6.x and 7.x releases, the default value for the `--binlog-format' option is `MIXED'. Each MySQL server used for replication in either cluster must be uniquely identified among all the MySQL replication servers participating in either cluster (you cannot have replication servers on both the master and slave clusters sharing the same ID). This can be done by starting each SQL node using the `--server-id=ID' option, where ID is a unique integer. Although it is not strictly necessary, we will assume for purposes of this discussion that all MySQL Cluster binaries are of the same release version. It is generally true in MySQL Replication that both MySQL servers (*Note `mysqld': mysqld. processes) involved must be compatible with one another with respect to both the version of the replication protocol used and the SQL feature sets which they support (see *Note replication-compatibility::). It is due to such differences between the binaries in the MySQL Cluster and MySQL Server 5.1 distributions that MySQL Cluster Replication has the additional requirement that both *Note `mysqld': mysqld. binaries come from a MySQL Cluster distribution. The simplest and easiest way to assure that the *Note `mysqld': mysqld. servers are compatible is to use the same MySQL Cluster distribution for all master and slave *Note `mysqld': mysqld. binaries. We assume that the slave server or cluster is dedicated to replication of the master, and that no other data is being stored on it. *Note*: It is possible to replicate a MySQL Cluster using statement-based replication. However, in this case, the following restrictions apply: * All updates to data rows on the cluster acting as the master must be directed to a single MySQL server. * It is not possible to replicate a cluster using multiple simultaneous MySQL replication processes. * Only changes made at the SQL level are replicated. These are in addition to the other limitations of statement-based replication as opposed to row-based replication; see *Note replication-sbr-rbr::, for more specific information concerning the differences between the two replication formats.  File: manual.info, Node: mysql-cluster-replication-issues, Next: mysql-cluster-replication-schema, Prev: mysql-cluster-replication-general, Up: mysql-cluster-replication 17.6.3 Known Issues in MySQL Cluster Replication ------------------------------------------------ The following are known problems or issues when using replication with MySQL Cluster in MySQL 5.1 (including MySQL Cluster NDB 6.X and 7.X through 7.1): * Loss of master-slave connection A loss of connection can occur either between the replication master SQL node and the replication slave SQL node, or between the replication master SQL node and the data nodes in the master cluster. In the latter case, this can occur not only as a result of loss of physical connection (for example, a broken network cable), but due to the overflow of data node event buffers; if the SQL node is too slow to respond, it may be dropped by the cluster (this is controllable to some degree by adjusting the `MaxBufferedEpochs' and `TimeBetweenEpochs' configuration parameters). If this occurs, _it is entirely possible for new data to be inserted into the master cluster without being recorded in the replication master's binary log_. For this reason, to guarantee high availability, it is extremely important to maintain a backup replication channel, to monitor the primary channel, and to fail over to the secondary replication channel when necessary to keep the slave cluster synchronized with the master. MySQL Cluster is not designed to perform such monitoring on its own; for this, an external application is required. Prior to MySQL 5.1.18, a MySQL Cluster replication slave *Note `mysqld': mysqld. had no way of detecting that the connection from the master had been interrupted. For this reason, it was possible for the slave to become inconsistent with the master. Beginning with MySQL 5.1.18, the replication master issues a `gap' event when connecting or reconnecting to the master cluster. (A gap event is a type of `incident event,' which indicates an incident that occurs that affects the contents of the database but that cannot easily be represented as a set of changes. Examples of incidents are server crashes, database resynchronization, (some) software updates, and (some) hardware changes.) When the slave encounters a gap in the replication log, it stops with an error message. This message is available in the output of *Note `SHOW SLAVE STATUS': show-slave-status, and indicates that the SQL thread has stopped due to an incident registered in the replication stream, and that manual intervention is required. See *Note mysql-cluster-replication-failover::, for more information about what to do in such circumstances. *Important*: Because MySQL Cluster is not designed on its own to monitor replication status or provide failover, if high availability is a requirement for the slave server or cluster, then you must set up multiple replication lines, monitor the master *Note `mysqld': mysqld. on the primary replication line, and be prepared fail over to a secondary line if and as necessary. This must be done manually, or possibly by means of a third-party application. For information about implementing this type of setup, see *Note mysql-cluster-replication-two-channels::, and *Note mysql-cluster-replication-failover::. However, if you are replicating from a standalone MySQL server to a MySQL Cluster, one channel is usually sufficient. * Multi-byte character sets Previously, there were several known issues with regard to the use of multi-byte characters sets with MySQL Cluster Replication. These were resolved in MySQL 5.1.21, MySQL Cluster NDB 6.2.14, and MySQL Cluster NDB 6.3.11. (See Bug#27404 and Bug#29562.) * Circular replication Prior to MySQL 5.1.18, circular replication was not supported with MySQL Cluster replication, due to the fact that all log events created in a particular MySQL Cluster were wrongly tagged with the server ID of the MySQL server used as master and not with the server ID of the originating server. Beginning with MySQL 5.1.18, this limitation is lifted, as discussed in the next few paragraphs, in which we consider the example of a replication setup involving three MySQL Clusters numbered 1, 2, and 3, in which Cluster 1 acts as the replication master for Cluster 2, Cluster 2 acts as the master for Cluster 3, and Cluster 3 acts as the master for Cluster 1. Each cluster has two SQL nodes, with SQL nodes A and B belonging to Cluster 1, SQL nodes C and D belonging to Cluster 2, and SQL nodes E and F belonging to Cluster 3. Circular replication using these clusters is supported as long as: * The SQL nodes on all masters and slaves are the same * All SQL nodes acting as replication masters and slaves are started using the `--log-slave-updates' option This type of circular replication setup is shown in the following diagram: MySQL Cluster circular replication scheme in which all master SQL nodes are also slaves. In this scenario, SQL node A in Cluster 1 replicates to SQL node C in Cluster 2; SQL node C replicates to SQL node E in Cluster 3; SQL node E replicates to SQL node A. In other words, the replication line (indicated by the red arrows in the diagram) directly connects all SQL nodes used as replication masters and slaves. It should also be possible to set up circular replication in which not all master SQL nodes are also slaves, as shown here: MySQL Cluster circular replication scheme in which all master SQL nodes are not also necessarily slaves. In this case, different SQL nodes in each cluster are used as replication masters and slaves. However, you must _not_ start any of the SQL nodes using `--log-slave-updates' (see the description of this option for more information). This type of circular replication scheme for MySQL Cluster, in which the line of replication (again indicated by the red arrows in the diagram) is discontinuous, should be possible, but it should be noted that it has not yet been thoroughly tested and must therefore still be considered experimental. *Note*: Beginning with MySQL 5.1.24, the *Note `NDB': mysql-cluster. storage engine uses _idempotent execution mode_, which suppresses duplicate-key and other errors that otherwise break circular replication of MySQL Cluster. This is equivalent to setting the global `slave_exec_mode' system variable to `IDEMPOTENT'. This is also required for multi-master replication when using MySQL Cluster. (Bug#31609) It is not necessary to set `slave_exec_mode' in MySQL Cluster replication; MySQL Cluster does this automatically for all *Note `NDB': mysql-cluster. tables and ignores any attempts to set this variable explicitly. * MySQL Cluster replication and primary keys In MySQL 5.1.6, only those *Note `NDB': mysql-cluster. tables having explicit primary keys could be replicated. This limitation was lifted in MySQL 5.1.7. However, in the event of a node failure, errors in replication of *Note `NDB': mysql-cluster. tables without primary keys can still occur, due to the possibility of duplicate rows being inserted in such cases. For this reason, it is highly recommended that all *Note `NDB': mysql-cluster. tables being replicated have primary keys. * MySQL Cluster Replication and Unique Keys Prior to MySQL Cluster NDB 7.0.25 and MySQL Cluster NDB 7.1.14, operations that updated values of unique key columns of *Note `NDB': mysql-cluster. tables could result in duplicate-key errors when replicated. This was due to the ordering of row events in the binary log according to the partitioning of the base table, which meant that they could appear in a different order from that in which they were originally executed. (Bug #11756082) In MySQL Cluster NDB 7.0.25, MySQL Cluster NDB 7.1.14, and later, this issue is solved for replication between *Note `NDB': mysql-cluster. tables by deferring unique key checks until after all table row updates have been performed. Deferring constraints in this way is currently supported only by *Note `NDB': mysql-cluster. Thus, updates of unique keys when replicating from *Note `NDB': mysql-cluster. to a different storage engine such as *Note `MyISAM': myisam-storage-engine. or *Note `InnoDB': innodb-storage-engine. are still not supported. The problem encountered when replicating without deferred checking of unique key updates can be illustrated using *Note `NDB': mysql-cluster. table such as `t', is created and populated on the master (and replicated to a slave that does not support deferred unique key updates) as shown here: CREATE TABLE t ( p INT PRIMARY KEY, c INT, UNIQUE KEY u (c) ) ENGINE NDB; INSERT INTO t VALUES (1,1), (2,2), (3,3), (4,4), (5,5); The following *Note `UPDATE': update. statement on `t' succeeded on the master, since the rows affected are processed in the order determined by the `ORDER BY' option, performed over the entire table: UPDATE t SET c = c - 1 ORDER BY p; However, the same statement failed with a duplicate key error or other constraint violation on the slave, because the ordering of the row updates was done for one partition at a time, rather than for the table as a whole. *Note*: In MySQL 5.1.6 and later, every *Note `NDB': mysql-cluster. table is implicitly partitioned by key when it is created. This also applies to all MySQL Cluster NDB 6.x and MySQL Cluster NDB 7.x releases. See *Note partitioning-key::, for more information. * Restarting with `--initial' Restarting the cluster with the `--initial' option causes the sequence of GCI and epoch numbers to start over from `0'. (This is generally true of MySQL Cluster and not limited to replication scenarios involving Cluster.) The MySQL servers involved in replication should in this case be restarted. After this, you should use the *Note `RESET MASTER': reset-master. and *Note `RESET SLAVE': reset-slave. statements to clear the invalid `ndb_binlog_index' and `ndb_apply_status' tables. respectively. * `auto_increment_offset' and `auto_increment_increment' variables The use of the `auto_increment_offset' and `auto_increment_increment' server system variables is supported beginning with MySQL 5.1.20. Previously, these produced unpredictable results when used with *Note `NDB': mysql-cluster. tables or MySQL Cluster replication. * Replication from `NDBCLUSTER' to other storage engines If you attempt to replicate from a MySQL Cluster to a slave that uses a storage engine that does not handle its own binary logging, the replication process aborts with the error `Binary logging not possible ... Statement cannot be written atomically since more than one engine involved and at least one engine is self-logging' (Error 1595). It is possible to work around this issue in one of the following ways: * Turn off binary logging on the slave This can be accomplished by setting `sql_log_bin = 0'. * Change the storage engine used for the `mysql.ndb_apply_status' table Causing this table to use an engine that does not handle its own binary logging can also eliminate the conflict. This can be done by issuing a statement such as `ALTER TABLE mysql.ndb_apply_status ENGINE=MyISAM' on the slave. It is safe to do this when using a non-*Note `NDB': mysql-cluster. storage engine on the slave, since you do not then need to worry about keeping multiple slave SQL nodes synchronized. * Filter out changes to the `mysql.ndb_apply_status' table on the slave This can be done by starting the slave SQL node with the option `--replicate-ignore-table=mysql.ndb_apply_status'. If you need for other tables to be ignored by replication, you might wish to use an appropriate `--replicate-wild-ignore-table' option instead. *Important*: You should _not_ disable replication or binary logging of `mysql.ndb_apply_status' or change the storage engine used for this table when replicating from one MySQL Cluster to another. See *Note mysql-cluster-replication-issues-filtering::, for details. * Replication from `NDB' to a different storage engine For replication from *Note `NDB': mysql-cluster. to a different storage engine, the relationship between the two databases must be a simple master-slave one. This means that circular or master-master replication is not supported between MySQL Cluster and other storage engines. However, the MySQL Cluster database can simultaneously replicate to multiple slave MySQL Cluster databases. In addition, it is not possible to configure more than one replication channel when replicating between MySQL Cluster and a different storage engine. If MySQL Cluster is the master then it is still possible to have more than one MySQL Server maintain a binary log of all changes; however, for the slave to change masters (fail over), the new master-slave relationship must be explicitly defined on the slave. * Replication from `NDB' to a nontransactional storage engine When replicating from *Note `NDB': mysql-cluster. to a nontransactional storage engine such as *Note `MyISAM': myisam-storage-engine, you may encounter unnecessary duplicate key errors when replicating *Note `INSERT ... ON DUPLICATE KEY UPDATE': insert-on-duplicate. statements. You can suppress these in MySQL Cluster NDB 6.2 and later MySQL Cluster releases by using `--ndb-log-update-as-write=0', which forces updates to be logged as writes (rather than as updates). You should also be aware that, when replicating from *Note `NDB': mysql-cluster. to a storage engine that does not implement transactions (such as *Note `MyISAM': myisam-storage-engine.), if the slave fails in applying one or more rows changes from a transaction, it does not roll back the rest of the transaction. Because of this, it cannot be guaranteed that transactional consistency will be maintained on the slave in this type of scenario. * Replication and binary log filtering rules with replication between MySQL Clusters If you are using any of the options `--replicate-do-*', `--replicate-ignore-*', `--binlog-do-db', or `--binlog-ignore-db' to filter databases or tables being replicated, care must be taken not to block replication or binary logging of the `mysql.ndb_apply_status', which is required for replication between MySQL Clusters to operate properly. In particular, you must keep in mind the following: 1. Using `--replicate-do-db=DB_NAME' (and no other `--replicate-do-*' or `--replicate-ignore-*' options) means that _only_ tables in database DB_NAME are replicated. In this case, you should also use `--replicate-do-db=mysql', `--binlog-do-db=mysql', or `--replicate-do-table=mysql.ndb_apply_status' to ensure that `mysql.ndb_apply_status' is populated on slaves. Using `--binlog-do-db=DB_NAME' (and no other `--binlog-do-db' options) means that changes _only_ to tables in database DB_NAME are written to the binary log. In this case, you should also use `--replicate-do-db=mysql', `--binlog-do-db=mysql', or `--replicate-do-table=mysql.ndb_apply_status' to ensure that `mysql.ndb_apply_status' is populated on slaves. 2. Using `--replicate-ignore-db=mysql' means that no tables in the `mysql' database are replicated. In this case, you should also use `--replicate-do-table=mysql.ndb_apply_status' to ensure that `mysql.ndb_apply_status' is replicated. Using `--binlog-ignore-db=mysql' means that no changes to tables in the `mysql' database are written to the binary log. In this case, you should also use `--replicate-do-table=mysql.ndb_apply_status' to ensure that `mysql.ndb_apply_status' is replicated. You should also remember that each replication rule requires the following: 1. Its own `--replicate-do-*' or `--replicate-ignore-*' option, and that multiple rules cannot be expressed in a single replication filtering option. For information about these rules, see *Note replication-options::. 2. Its own `--binlog-do-db' or `--binlog-ignore-db' option, and that multiple rules cannot be expressed in a single binary log filtering option. For information about these rules, see *Note binary-log::. *Note*: If you are replicating a MySQL Cluster to a slave that uses a storage engine other than *Note `NDBCLUSTER': mysql-cluster, the considerations just given previously may not apply. See `Replication from *Note `NDBCLUSTER': mysql-cluster. to other storage engines' elsewhere in this section for details. * MySQL Cluster Replication and IPv6 Currently, the NDB API and MGM API do not support IPv6. However, beginning with MySQL Cluster NDB 6.4.1, MySQL Servers--including those acting as SQL nodes in a MySQL Cluster--can use IPv6 to contact other MySQL Servers. This means that you can replicate between MySQL Clusters using IPv6 to connect the master and slave SQL nodes as shown by the dotted arrow in the following diagram: IPv6 Used to Connect Between MySQL Cluster SQL Nodes in Replication However, all connections originating _within_ the MySQL Cluster--shown in the diagram by solid arrows--must use IPv4. All MySQL Cluster data nodes, management servers, and management clients must be accessible from one another using IPv4. In addition, SQL nodes must use IPv4 to communicate with the cluster. There is not currently any support in the NDB and MGM APIs for IPv6, which means that any applications written using these APIs must also make all connections using IPv4. * Attribute promotion and demotion Formerly, support in MySQL Cluster for type conversions between columns of similar but different types on the master and the slave was extremely limited. However, starting with MySQL Cluster NDB 6.3.33, 7.0.14, and 7.1.3, MySQL Cluster Replication includes support for attribute promotion and demotion. The implementation of the latter distinguishes between lossy and non-lossy type conversions, and their use on the slave can be controlled by setting the `slave_type_conversions' global server system variable. For more information about attribute promotion and demotion in MySQL Cluster, see *Note replication-features-attribute-promotion::.  File: manual.info, Node: mysql-cluster-replication-schema, Next: mysql-cluster-replication-preparation, Prev: mysql-cluster-replication-issues, Up: mysql-cluster-replication 17.6.4 MySQL Cluster Replication Schema and Tables -------------------------------------------------- Replication in MySQL Cluster makes use of a number of dedicated tables in the `mysql' database on each MySQL Server instance acting as an SQL node in both the cluster being replicated and the replication slave (whether the slave is a single server or a cluster). These tables are created during the MySQL installation process by the *Note `mysql_install_db': mysql-install-db. script, and include a table for storing the binary log's indexing data. Since the `ndb_binlog_index' table is local to each MySQL server and does not participate in clustering, it uses the `MyISAM' storage engine. This means that it must be created separately on each *Note `mysqld': mysqld. participating in the master cluster. (However, the binlog itself contains updates from all MySQL servers in the cluster to be replicated.) This table is defined as follows: CREATE TABLE `ndb_binlog_index` ( `Position` BIGINT(20) UNSIGNED NOT NULL, `File` VARCHAR(255) NOT NULL, `epoch` BIGINT(20) UNSIGNED NOT NULL, `inserts` BIGINT(20) UNSIGNED NOT NULL, `updates` BIGINT(20) UNSIGNED NOT NULL, `deletes` BIGINT(20) UNSIGNED NOT NULL, `schemaops` BIGINT(20) UNSIGNED NOT NULL, PRIMARY KEY (`epoch`) ) ENGINE=MYISAM DEFAULT CHARSET=latin1; *Important*: Prior to MySQL 5.1.14, the `ndb_binlog_index' table was known as `binlog_index', and was kept in a separate `cluster' database, which in MySQL 5.1.7 and earlier was known as the `cluster_replication' database. Similarly, the `ndb_apply_status' and `ndb_schema' tables were known as `apply_status' and `schema', and were also found in the `cluster' (earlier `cluster_replication') database. However, beginning with MySQL 5.1.14, all MySQL Cluster replication tables reside in the `mysql' system database. Information about how this change affects upgrades from MySQL Cluster 5.1.13 and earlier to 5.1.14 and later versions can be found in *Note news-5-1-14::. Beginning with MySQL Cluster NDB 6.3.2, this table has been changed to facilitate 3-way replication recovery. Two columns `orig_server_id' and `orig_epoch' have been added to this table; when *Note `mysqld': mysqld. is started with the `--ndb-log-orig' option, these columns store, respectively, the ID of the server on which the event originated and the epoch in which the event took place on the originating server. In addition, the table's primary key now includes these two columns. The modified table definition is shown here: CREATE TABLE `ndb_binlog_index` ( `Position` BIGINT(20) UNSIGNED NOT NULL, `File` VARCHAR(255) NOT NULL, `epoch` BIGINT(20) UNSIGNED NOT NULL, `inserts` INT(10) UNSIGNED NOT NULL, `updates` INT(10) UNSIGNED NOT NULL, `deletes` INT(10) UNSIGNED NOT NULL, `schemaops` INT(10) UNSIGNED NOT NULL, `orig_server_id` INT(10) UNSIGNED NOT NULL, `orig_epoch` BIGINT(20) UNSIGNED NOT NULL, `gci` INT(10) UNSIGNED NOT NULL, PRIMARY KEY (`epoch`,`orig_server_id`,`orig_epoch`) ) ENGINE=MyISAM DEFAULT CHARSET=latin1; The `gci' column was added in MySQL Cluster NDB 6.2.6 and MySQL Cluster NDB 6.3.2. The following figure shows the relationship of the MySQL Cluster replication master server, its binlog injector thread, and the `mysql.ndb_binlog_index' table. The replication master cluster, the binlog-injector thread, and the `ndb_binlog_index' table An additional table, named `ndb_apply_status', is used to keep a record of the operations that have been replicated from the master to the slave. Unlike the case with `ndb_binlog_index', the data in this table is not specific to any one SQL node in the (slave) cluster, and so `ndb_apply_status' can use the `NDBCLUSTER' storage engine, as shown here: CREATE TABLE `ndb_apply_status` ( `server_id` INT(10) UNSIGNED NOT NULL, `epoch` BIGINT(20) UNSIGNED NOT NULL, `log_name` VARCHAR(255) CHARACTER SET latin1 COLLATE latin1_bin NOT NULL, `start_pos` BIGINT(20) UNSIGNED NOT NULL, `end_pos` BIGINT(20) UNSIGNED NOT NULL, PRIMARY KEY (`server_id`) USING HASH ) ENGINE=NDBCLUSTER DEFAULT CHARSET=latin1; This table is populated only on slaves; on the master, no `DataMemory' is allocated to it. Since this table is populated from data originating on the master, it should be allowed to replicate; any replication filtering or binary log filtering rules that inadvertently prevent the slave from updating `ndb_apply_status' or the master from writing into the binary log may prevent replication between clusters from operating properly. For more information about potential problems arising from such filtering rules, see *Note mysql-cluster-replication-issues-filtering::. The `log_name', `start_pos', and `end_pos' columns were added in MySQL 5.1.18. *Important*: If you are using MySQL Cluster replication, see *Note mysql-cluster-upgrade-downgrade-compatibility-5.1:: before upgrading to MySQL 5.1.18 or later from an earlier version. The `ndb_binlog_index' and `ndb_apply_status' tables are created in the `mysql' database because they should not be explicitly replicated by the user. User intervention is normally not required to create or maintain either of these tables, since both `ndb_binlog_index' and the `ndb_apply_status' are maintained by the *Note `NDB': mysql-cluster. binary log (binlog) injector thread. This keeps the master *Note `mysqld': mysqld. process updated to changes performed by the *Note `NDB': mysql-cluster. storage engine. The *Note `NDB': mysql-cluster. _binlog injector thread_ receives events directly from the *Note `NDB': mysql-cluster. storage engine. The *Note `NDB': mysql-cluster. injector is responsible for capturing all the data events within the cluster, and ensures that all events which change, insert, or delete data are recorded in the `ndb_binlog_index' table. The slave I/O thread transfers the events from the master's binary log to the slave's relay log. However, it is advisable to check for the existence and integrity of these tables as an initial step in preparing a MySQL Cluster for replication. It is possible to view event data recorded in the binary log by querying the `mysql.ndb_binlog_index' table directly on the master. This can be also be accomplished using the *Note `SHOW BINLOG EVENTS': show-binlog-events. statement on either the replication master or slave MySQL servers. (See *Note show-binlog-events::.) You can also obtain useful information from the output of *Note `SHOW ENGINE NDB STATUS': show-engine. The `ndb_schema' table is used to track schema changes made to *Note `NDB': mysql-cluster. tables. It is defined as shown here: CREATE TABLE ndb_schema ( `db` VARBINARY(63) NOT NULL, `name` VARBINARY(63) NOT NULL, `slock` BINARY(32) NOT NULL, `query` BLOB NOT NULL, `node_id` INT UNSIGNED NOT NULL, `epoch` BIGINT UNSIGNED NOT NULL, `id` INT UNSIGNED NOT NULL, `version` INT UNSIGNED NOT NULL, `type` INT UNSIGNED NOT NULL, PRIMARY KEY USING HASH (db,name) ) ENGINE=NDB DEFAULT CHARSET=latin1; Unlike the two tables previously mentioned in this section, the `ndb_schema' table is not visible either to MySQL *Note `SHOW': show. statements, or in any `INFORMATION_SCHEMA' tables; however, it can be seen in the output of *Note `ndb_show_tables': mysql-cluster-programs-ndb-show-tables, as shown here: shell> ndb_show_tables -t 2 id type state logging database schema name 4 UserTable Online Yes mysql def ndb_apply_status 5 UserTable Online Yes ndbworld def City 6 UserTable Online Yes ndbworld def Country 3 UserTable Online Yes mysql def NDB$BLOB_2_3 7 UserTable Online Yes ndbworld def CountryLanguage _2 UserTable Online Yes mysql def ndb_schema_ NDBT_ProgramExit: 0 - OK It is also possible to *Note `SELECT': select. from this table in *Note `mysql': mysql. and other MySQL client applications, as shown here: mysql> SELECT * FROM mysql.ndb_schema WHERE name='City' \G *************************** 1. row *************************** db: ndbworld name: City slock: query: alter table City engine=ndb node_id: 4 epoch: 0 id: 0 version: 0 type: 7 1 row in set (0.00 sec) This can sometimes be useful when debugging applications. *Note*: When performing schema changes on *Note `NDB': mysql-cluster. tables, applications should wait until the *Note `ALTER TABLE': alter-table. statement has returned in the MySQL client connection that issued the statement before attempting to use the updated definition of the table. The `ndb_schema' table was added in MySQL 5.1.8. Beginning with MySQL 5.1.14, if the `ndb_apply_status' table or the `ndb_schema' table does not exist on the slave, *Note `ndb_restore': mysql-cluster-programs-ndb-restore. re-creates the missing table or tables (Bug#14612). Conflict resolution for MySQL Cluster Replication requires the presence of an additional `mysql.ndb_replication' table. Currently, this table must be created manually. For information about how to do this, see *Note mysql-cluster-replication-conflict-resolution::.  File: manual.info, Node: mysql-cluster-replication-preparation, Next: mysql-cluster-replication-starting, Prev: mysql-cluster-replication-schema, Up: mysql-cluster-replication 17.6.5 Preparing the MySQL Cluster for Replication -------------------------------------------------- Preparing the MySQL Cluster for replication consists of the following steps: 1. Check all MySQL servers for version compatibility (see *Note mysql-cluster-replication-general::). 2. Create a slave account on the master Cluster with the appropriate privileges: mysqlM> GRANT REPLICATION SLAVE -> ON *.* TO 'SLAVE_USER'@'SLAVE_HOST' -> IDENTIFIED BY 'SLAVE_PASSWORD'; In the previous statement, SLAVE_USER is the slave account user name, SLAVE_HOST is the host name or IP address of the replication slave, and SLAVE_PASSWORD is the password to assign to this account. For example, to create a slave user account with the name ``myslave',' logging in from the host named ``rep-slave',' and using the password ``53cr37',' use the following *Note `GRANT': grant. statement: mysqlM> GRANT REPLICATION SLAVE -> ON *.* TO 'myslave'@'rep-slave' -> IDENTIFIED BY '53cr37'; For security reasons, it is preferable to use a unique user account--not employed for any other purpose--for the replication slave account. 3. Configure the slave to use the master. Using the MySQL Monitor, this can be accomplished with the *Note `CHANGE MASTER TO': change-master-to. statement: mysqlS> CHANGE MASTER TO -> MASTER_HOST='MASTER_HOST', -> MASTER_PORT=MASTER_PORT, -> MASTER_USER='SLAVE_USER', -> MASTER_PASSWORD='SLAVE_PASSWORD'; In the previous statement, MASTER_HOST is the host name or IP address of the replication master, MASTER_PORT is the port for the slave to use for connecting to the master, SLAVE_USER is the user name set up for the slave on the master, and SLAVE_PASSWORD is the password set for that user account in the previous step. For example, to tell the slave to replicate from the MySQL server whose host name is ``rep-master',' using the replication slave account created in the previous step, use the following statement: mysqlS> CHANGE MASTER TO -> MASTER_HOST='rep-master', -> MASTER_PORT=3306, -> MASTER_USER='myslave', -> MASTER_PASSWORD='53cr37'; For a complete list of clauses that can be used with this statement, see *Note change-master-to::. You can also configure the slave to use the master by setting the corresponding startup options in the slave server's `my.cnf' file. To configure the slave in the same way as the preceding example *Note `CHANGE MASTER TO': change-master-to. statement, the following information would need to be included in the slave's `my.cnf' file: [mysqld] master-host=rep-master master-port=3306 master-user=myslave master-password=53cr37 For additional options that can be set in `my.cnf' for replication slaves, see *Note replication-options::. *Note*: To provide replication backup capability, you will also need to add an `ndb-connectstring' option to the slave's `my.cnf' file prior to starting the replication process. See *Note mysql-cluster-replication-backups::, for details. 4. If the master cluster is already in use, you can create a backup of the master and load this onto the slave to cut down on the amount of time required for the slave to synchronize itself with the master. If the slave is also running MySQL Cluster, this can be accomplished using the backup and restore procedure described in *Note mysql-cluster-replication-backups::. ndb-connectstring=MANAGEMENT_HOST[:PORT] In the event that you are _not_ using MySQL Cluster on the replication slave, you can create a backup with this command on the replication master: shellM> mysqldump --master-data=1 Then import the resulting data dump onto the slave by copying the dump file over to the slave. After this, you can use the *Note `mysql': mysql. client to import the data from the dumpfile into the slave database as shown here, where DUMP_FILE is the name of the file that was generated using *Note `mysqldump': mysqldump. on the master, and DB_NAME is the name of the database to be replicated: shellS> mysql -u root -p DB_NAME < DUMP_FILE For a complete list of options to use with *Note `mysqldump': mysqldump, see *Note mysqldump::. *Note*: If you copy the data to the slave in this fashion, you should make sure that the slave is started with the `--skip-slave-start' option on the command line, or else include `skip-slave-start' in the slave's `my.cnf' file to keep it from trying to connect to the master to begin replicating before all the data has been loaded. Once the data loading has completed, follow the additional steps outlined in the next two sections. 5. Ensure that each MySQL server acting as a replication master is configured with a unique server ID, and with binary logging enabled, using the row format. (See *Note replication-formats::.) These options can be set either in the master server's `my.cnf' file, or on the command line when starting the master *Note `mysqld': mysqld. process. See *Note mysql-cluster-replication-starting::, for information regarding the latter option.  File: manual.info, Node: mysql-cluster-replication-starting, Next: mysql-cluster-replication-two-channels, Prev: mysql-cluster-replication-preparation, Up: mysql-cluster-replication 17.6.6 Starting MySQL Cluster Replication (Single Replication Channel) ---------------------------------------------------------------------- This section outlines the procedure for starting MySQL Cluster replication using a single replication channel. 1. Start the MySQL replication master server by issuing this command: shellM> mysqld --ndbcluster --server-id=ID \ --log-bin --binlog-format=ROW & In the previous statement, ID is this server's unique ID (see *Note mysql-cluster-replication-general::). This starts the server's *Note `mysqld': mysqld. process with binary logging enabled using the proper logging format. *Note*: You can also start the master with `--binlog-format=MIXED', in which case row-based replication is used automatically when replicating between clusters. 2. Start the MySQL replication slave server as shown here: shellS> mysqld --ndbcluster --server-id=ID & In the command just shown, ID is the slave server's unique ID. It is not necessary to enable logging on the replication slave. *Note*: You should use the `--skip-slave-start' option with this command or else you should include `skip-slave-start' in the slave server's `my.cnf' file, unless you want replication to begin immediately. With the use of this option, the start of replication is delayed until the appropriate *Note `START SLAVE': start-slave. statement has been issued, as explained in Step 4 below. 3. It is necessary to synchronize the slave server with the master server's replication binlog. If binary logging has not previously been running on the master, run the following statement on the slave: mysqlS> CHANGE MASTER TO -> MASTER_LOG_FILE='', -> MASTER_LOG_POS=4; This instructs the slave to begin reading the master's binary log from the log's starting point. Otherwise--that is, if you are loading data from the master using a backup--see *Note mysql-cluster-replication-failover::, for information on how to obtain the correct values to use for `MASTER_LOG_FILE' and `MASTER_LOG_POS' in such cases. 4. Finally, you must instruct the slave to begin applying replication by issuing this command from the *Note `mysql': mysql. client on the replication slave: mysqlS> START SLAVE; This also initiates the transmission of replication data from the master to the slave. It is also possible to use two replication channels, in a manner similar to the procedure described in the next section; the differences between this and using a single replication channel are covered in *Note mysql-cluster-replication-two-channels::. Beginning with MySQL Cluster NDB 6.2.3, it is possible to improve cluster replication performance by enabling _batched updates_. This can be accomplished by setting the `slave_allow_batching' system variable on the slave *Note `mysqld': mysqld. processes. Normally, updates are applied as soon as they are received. However, the use of batching causes updates to be applied in 32 KB batches, which can result in higher throughput and less CPU usage, particularly where individual updates are relatively small. *Note*: Slave batching works on a per-epoch basis; updates belonging to more than one transaction can be sent as part of the same batch. All outstanding updates are applied when the end of an epoch is reached, even if the updates total less than 32 KB. Batching can be turned on and off at runtime. To activate it at runtime, you can use either of these two statements: SET GLOBAL slave_allow_batching = 1; SET GLOBAL slave_allow_batching = ON; If a particular batch causes problems (such as a statement whose effects do not appear to be replicated correctly), slave batching can be deactivated using either of the following statements: SET GLOBAL slave_allow_batching = 0; SET GLOBAL slave_allow_batching = OFF; You can check whether slave batching is currently being used by means of an appropriate *Note `SHOW VARIABLES': show-variables. statement, like this one: mysql> SHOW VARIABLES LIKE 'slave%'; +---------------------------+-------+ | Variable_name | Value | +---------------------------+-------+ | slave_allow_batching | ON | | slave_compressed_protocol | OFF | | slave_load_tmpdir | /tmp | | slave_net_timeout | 3600 | | slave_skip_errors | OFF | | slave_transaction_retries | 10 | +---------------------------+-------+ 6 rows in set (0.00 sec)  File: manual.info, Node: mysql-cluster-replication-two-channels, Next: mysql-cluster-replication-failover, Prev: mysql-cluster-replication-starting, Up: mysql-cluster-replication 17.6.7 Using Two Replication Channels for MySQL Cluster Replication ------------------------------------------------------------------- In a more complete example scenario, we envision two replication channels to provide redundancy and thereby guard against possible failure of a single replication channel. This requires a total of four replication servers, two masters for the master cluster and two slave servers for the slave cluster. For purposes of the discussion that follows, we assume that unique identifiers are assigned as shown here: Server ID Description 1 Master - primary replication channel (_M_) 2 Master - secondary replication channel (_M'_) 3 Slave - primary replication channel (_S_) 4 Slave - secondary replication channel (_S'_) Setting up replication with two channels is not radically different from setting up a single replication channel. First, the *Note `mysqld': mysqld. processes for the primary and secondary replication masters must be started, followed by those for the primary and secondary slaves. Then the replication processes may be initiated by issuing the *Note `START SLAVE': start-slave. statement on each of the slaves. The commands and the order in which they need to be issued are shown here: 1. Start the primary replication master: shellM> mysqld --ndbcluster --server-id=1 \ --log-bin --binlog-format=row & 2. Start the secondary replication master: shellM'> mysqld --ndbcluster --server-id=2 \ --log-bin --binlog-format=row & 3. Start the primary replication slave server: shellS> mysqld --ndbcluster --server-id=3 \ --skip-slave-start & 4. Start the secondary replication slave: shellS'> mysqld --ndbcluster --server-id=4 \ --skip-slave-start & 5. Finally, initiate replication on the primary channel by executing the *Note `START SLAVE': start-slave. statement on the primary slave as shown here: mysqlS> START SLAVE; *Warning*: Only the primary channel is to be started at this point. The secondary replication channel is to be started only in the event that the primary replication channel fails, as described in *Note mysql-cluster-replication-failover::. Running multiple replication channels simultaneously can result in unwanted duplicate records being created on the replication slaves. As mentioned previously, it is not necessary to enable binary logging on replication slaves.  File: manual.info, Node: mysql-cluster-replication-failover, Next: mysql-cluster-replication-backups, Prev: mysql-cluster-replication-two-channels, Up: mysql-cluster-replication 17.6.8 Implementing Failover with MySQL Cluster Replication ----------------------------------------------------------- In the event that the primary Cluster replication process fails, it is possible to switch over to the secondary replication channel. The following procedure describes the steps required to accomplish this. 1. Obtain the time of the most recent global checkpoint (GCP). That is, you need to determine the most recent epoch from the `ndb_apply_status' table on the slave cluster, which can be found using the following query: mysqlS'> SELECT @latest:=MAX(epoch) -> FROM mysql.ndb_apply_status; 2. Using the information obtained from the query shown in Step 1, obtain the corresponding records from the `ndb_binlog_index' table on the master cluster as shown here: mysqlM'> SELECT -> @file:=SUBSTRING_INDEX(File, '/', -1), -> @pos:=Position -> FROM mysql.ndb_binlog_index -> WHERE epoch > @latest -> ORDER BY epoch ASC LIMIT 1; These are the records saved on the master since the failure of the primary replication channel. We have employed a user variable `@latest' here to represent the value obtained in Step 1. Of course, it is not possible for one *Note `mysqld': mysqld. instance to access user variables set on another server instance directly. These values must be `plugged in' to the second query manually or in application code. 3. Now it is possible to synchronize the secondary channel by running the following query on the secondary slave server: mysqlS'> CHANGE MASTER TO -> MASTER_LOG_FILE='@file', -> MASTER_LOG_POS=@pos; Again we have employed user variables (in this case `@file' and `@pos') to represent the values obtained in Step 2 and applied in Step 3; in practice these values must be inserted manually or using application code that can access both of the servers involved. *Note*: `@file' is a string value such as `'/var/log/mysql/replication-master-bin.00001'', and so must be quoted when used in SQL or application code. However, the value represented by `@pos' must _not_ be quoted. Although MySQL normally attempts to convert strings to numbers, this case is an exception. 4. You can now initiate replication on the secondary channel by issuing the appropriate command on the secondary slave *Note `mysqld': mysqld.: mysqlS'> START SLAVE; Once the secondary replication channel is active, you can investigate the failure of the primary and effect repairs. The precise actions required to do this will depend upon the reasons for which the primary channel failed. *Warning*: The secondary replication channel is to be started only if and when the primary replication channel has failed. Running multiple replication channels simultaneously can result in unwanted duplicate records being created on the replication slaves. If the failure is limited to a single server, it should (in theory) be possible to replicate from M to S', or from M' to S; however, this has not yet been tested.  File: manual.info, Node: mysql-cluster-replication-backups, Next: mysql-cluster-replication-multi-master, Prev: mysql-cluster-replication-failover, Up: mysql-cluster-replication 17.6.9 MySQL Cluster Backups With MySQL Cluster Replication ----------------------------------------------------------- * Menu: * mysql-cluster-replication-auto-sync:: MySQL Cluster Replication: Automating Synchronization of the Replication Slave to the Master Binary Log * mysql-cluster-replication-pitr:: Point-In-Time Recovery Using MySQL Cluster Replication This section discusses making backups and restoring from them using MySQL Cluster replication. We assume that the replication servers have already been configured as covered previously (see *Note mysql-cluster-replication-preparation::, and the sections immediately following). This having been done, the procedure for making a backup and then restoring from it is as follows: 1. There are two different methods by which the backup may be started. * Method A This method requires that the cluster backup process was previously enabled on the master server, prior to starting the replication process. This can be done by including the following line in a `[mysql_cluster]' section in the `my.cnf file', where MANAGEMENT_HOST is the IP address or host name of the *Note `NDB': mysql-cluster. management server for the master cluster, and PORT is the management server's port number: ndb-connectstring=MANAGEMENT_HOST[:PORT] *Note*: The port number needs to be specified only if the default port (1186) is not being used. See *Note mysql-cluster-install-configuration::, for more information about ports and port allocation in MySQL Cluster. In this case, the backup can be started by executing this statement on the replication master: shellM> ndb_mgm -e "START BACKUP" * Method B If the `my.cnf' file does not specify where to find the management host, you can start the backup process by passing this information to the *Note `NDB': mysql-cluster. management client as part of the `START BACKUP' command. This can be done as shown here, where MANAGEMENT_HOST and PORT are the host name and port number of the management server: shellM> ndb_mgm MANAGEMENT_HOST:PORT -e "START BACKUP" In our scenario as outlined earlier (see *Note mysql-cluster-replication-preparation::), this would be executed as follows: shellM> ndb_mgm rep-master:1186 -e "START BACKUP" 2. Copy the cluster backup files to the slave that is being brought on line. Each system running an *Note `ndbd': mysql-cluster-programs-ndbd. process for the master cluster will have cluster backup files located on it, and _all_ of these files must be copied to the slave to ensure a successful restore. The backup files can be copied into any directory on the computer where the slave management host resides, so long as the MySQL and NDB binaries have read permissions in that directory. In this case, we will assume that these files have been copied into the directory `/var/BACKUPS/BACKUP-1'. It is not necessary that the slave cluster have the same number of *Note `ndbd': mysql-cluster-programs-ndbd. processes (data nodes) as the master; however, it is highly recommended this number be the same. It _is_ necessary that the slave be started with the `--skip-slave-start' option, to prevent premature startup of the replication process. 3. Create any databases on the slave cluster that are present on the master cluster that are to be replicated to the slave. *Important*: A *Note `CREATE DATABASE': create-database. (or *Note `CREATE SCHEMA': create-database.) statement corresponding to each database to be replicated must be executed on each SQL node in the slave cluster. 4. Reset the slave cluster using this statement in the MySQL Monitor: mysqlS> RESET SLAVE; It is important to make sure that the slave's `apply_status' table does not contain any records prior to running the restore process. You can accomplish this by running this SQL statement on the slave: mysqlS> DELETE FROM mysql.ndb_apply_status; 5. You can now start the cluster restoration process on the replication slave using the *Note `ndb_restore': mysql-cluster-programs-ndb-restore. command for each backup file in turn. For the first of these, it is necessary to include the `-m' option to restore the cluster metadata: shellS> ndb_restore -c SLAVE_HOST:PORT -n NODE-ID \ -b BACKUP-ID -m -r DIR DIR is the path to the directory where the backup files have been placed on the replication slave. For the *Note `ndb_restore': mysql-cluster-programs-ndb-restore. commands corresponding to the remaining backup files, the `-m' option should _not_ be used. For restoring from a master cluster with four data nodes (as shown in the figure in *Note mysql-cluster-replication::) where the backup files have been copied to the directory `/var/BACKUPS/BACKUP-1', the proper sequence of commands to be executed on the slave might look like this: shellS> ndb_restore -c rep-slave:1186 -n 2 -b 1 -m \ -r ./var/BACKUPS/BACKUP-1 shellS> ndb_restore -c rep-slave:1186 -n 3 -b 1 \ -r ./var/BACKUPS/BACKUP-1 shellS> ndb_restore -c rep-slave:1186 -n 4 -b 1 \ -r ./var/BACKUPS/BACKUP-1 shellS> ndb_restore -c rep-slave:1186 -n 5 -b 1 -e \ -r ./var/BACKUPS/BACKUP-1 *Important*: The `-e' (or `--restore-epoch') option in the final invocation of *Note `ndb_restore': mysql-cluster-programs-ndb-restore. in this example is required in order that the epoch is written to the slave `mysql.ndb_apply_status'. Without this information, the slave will not be able to synchronize properly with the master. (See *Note mysql-cluster-programs-ndb-restore::.) 6. Now you need to obtain the most recent epoch from the `ndb_apply_status' table on the slave (as discussed in *Note mysql-cluster-replication-failover::): mysqlS> SELECT @latest:=MAX(epoch) FROM mysql.ndb_apply_status; 7. Using `@latest' as the epoch value obtained in the previous step, you can obtain the correct starting position `@pos' in the correct binary log file `@file' from the master's `mysql.ndb_binlog_index' table using the query shown here: mysqlM> SELECT -> @file:=SUBSTRING_INDEX(File, '/', -1), -> @pos:=Position -> FROM mysql.ndb_binlog_index -> WHERE epoch > @latest -> ORDER BY epoch ASC LIMIT 1; In the event that there is currently no replication traffic, you can get this information by running *Note `SHOW MASTER STATUS': show-master-status. on the master and using the value in the `Position' column for the file whose name has the suffix with the greatest value for all files shown in the `File' column. However, in this case, you must determine this and supply it in the next step manually or by parsing the output with a script. 8. Using the values obtained in the previous step, you can now issue the appropriate *Note `CHANGE MASTER TO': change-master-to. statement in the slave's *Note `mysql': mysql. client: mysqlS> CHANGE MASTER TO -> MASTER_LOG_FILE='@file', -> MASTER_LOG_POS=@pos; 9. Now that the slave `knows' from what point in which `binlog' file to start reading data from the master, you can cause the slave to begin replicating with this standard MySQL statement: mysqlS> START SLAVE; To perform a backup and restore on a second replication channel, it is necessary only to repeat these steps, substituting the host names and IDs of the secondary master and slave for those of the primary master and slave replication servers where appropriate, and running the preceding statements on them. For additional information on performing Cluster backups and restoring Cluster from backups, see *Note mysql-cluster-backup::.  File: manual.info, Node: mysql-cluster-replication-auto-sync, Next: mysql-cluster-replication-pitr, Prev: mysql-cluster-replication-backups, Up: mysql-cluster-replication-backups 17.6.9.1 MySQL Cluster Replication: Automating Synchronization of the Replication Slave to the Master Binary Log ................................................................................................................ It is possible to automate much of the process described in the previous section (see *Note mysql-cluster-replication-backups::). The following Perl script `reset-slave.pl' serves as an example of how you can do this. #!/user/bin/perl -w # file: reset-slave.pl # Copyright (C)2005 MySQL AB # This program is free software; you can redistribute it and/or modify # it under the terms of the GNU General Public License as published by # the Free Software Foundation; either version 2 of the License, or # (at your option) any later version. # This program is distributed in the hope that it will be useful, # but WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the # GNU General Public License for more details. # You should have received a copy of the GNU General Public License # along with this program; if not, write to: # Free Software Foundation, Inc. # 59 Temple Place, Suite 330 # Boston, MA 02111-1307 USA # # Version 1.1 ######################## Includes ############################### use DBI; ######################## Globals ################################ my $m_host=''; my $m_port=''; my $m_user=''; my $m_pass=''; my $s_host=''; my $s_port=''; my $s_user=''; my $s_pass=''; my $dbhM=''; my $dbhS=''; ####################### Sub Prototypes ########################## sub CollectCommandPromptInfo; sub ConnectToDatabases; sub DisconnectFromDatabases; sub GetSlaveEpoch; sub GetMasterInfo; sub UpdateSlave; ######################## Program Main ########################### CollectCommandPromptInfo; ConnectToDatabases; GetSlaveEpoch; GetMasterInfo; UpdateSlave; DisconnectFromDatabases; ################## Collect Command Prompt Info ################## sub CollectCommandPromptInfo { ### Check that user has supplied correct number of command line args die "Usage:\n reset-slave >master MySQL host< >master MySQL port< \n >master user< >master pass< >slave MySQL host< \n >slave MySQL port< >slave user< >slave pass< \n All 8 arguments must be passed. Use BLANK for NULL passwords\n" unless @ARGV == 8; $m_host = $ARGV[0]; $m_port = $ARGV[1]; $m_user = $ARGV[2]; $m_pass = $ARGV[3]; $s_host = $ARGV[4]; $s_port = $ARGV[5]; $s_user = $ARGV[6]; $s_pass = $ARGV[7]; if ($m_pass eq "BLANK") { $m_pass = '';} if ($s_pass eq "BLANK") { $s_pass = '';} } ############### Make connections to both databases ############# sub ConnectToDatabases { ### Connect to both master and slave cluster databases ### Connect to master $dbhM = DBI->connect( "dbi:mysql:database=mysql;host=$m_host;port=$m_port", "$m_user", "$m_pass") or die "Can't connect to Master Cluster MySQL process! Error: $DBI::errstr\n"; ### Connect to slave $dbhS = DBI->connect( "dbi:mysql:database=mysql;host=$s_host", "$s_user", "$s_pass") or die "Can't connect to Slave Cluster MySQL process! Error: $DBI::errstr\n"; } ################ Disconnect from both databases ################ sub DisconnectFromDatabases { ### Disconnect from master $dbhM->disconnect or warn " Disconnection failed: $DBI::errstr\n"; ### Disconnect from slave $dbhS->disconnect or warn " Disconnection failed: $DBI::errstr\n"; } ###################### Find the last good GCI ################## sub GetSlaveEpoch { $sth = $dbhS->prepare("SELECT MAX(epoch) FROM mysql.ndb_apply_status;") or die "Error while preparing to select epoch from slave: ", $dbhS->errstr; $sth->execute or die "Selecting epoch from slave error: ", $sth->errstr; $sth->bind_col (1, \$epoch); $sth->fetch; print "\tSlave Epoch = $epoch\n"; $sth->finish; } ####### Find the position of the last GCI in the binlog ######## sub GetMasterInfo { $sth = $dbhM->prepare("SELECT SUBSTRING_INDEX(File, '/', -1), Position FROM mysql.ndb_binlog_index WHERE epoch > $epoch ORDER BY epoch ASC LIMIT 1;") or die "Prepare to select from master error: ", $dbhM->errstr; $sth->execute or die "Selecting from master error: ", $sth->errstr; $sth->bind_col (1, \$binlog); $sth->bind_col (2, \$binpos); $sth->fetch; print "\tMaster bin log = $binlog\n"; print "\tMaster Bin Log position = $binpos\n"; $sth->finish; } ########## Set the slave to process from that location ######### sub UpdateSlave { $sth = $dbhS->prepare("CHANGE MASTER TO MASTER_LOG_FILE='$binlog', MASTER_LOG_POS=$binpos;") or die "Prepare to CHANGE MASTER error: ", $dbhS->errstr; $sth->execute or die "CHANGE MASTER on slave error: ", $sth->errstr; $sth->finish; print "\tSlave has been updated. You may now start the slave.\n"; } # end reset-slave.pl  File: manual.info, Node: mysql-cluster-replication-pitr, Prev: mysql-cluster-replication-auto-sync, Up: mysql-cluster-replication-backups 17.6.9.2 Point-In-Time Recovery Using MySQL Cluster Replication ............................................................... _Point-in-time_ recovery--that is, recovery of data changes made since a given point in time--is performed after restoring a full backup that returns the server to its state when the backup was made. Performing point-in-time recovery of MySQL Cluster tables with MySQL Cluster and MySQL Cluster Replication can be accomplished using a native *Note `NDB': mysql-cluster. data backup (taken by issuing `CREATE BACKUP' in the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client) and restoring the `ndb_binlog_index' table (from a dump made using *Note `mysqldump': mysqldump.). To perform point-in-time recovery of MySQL Cluster, it is necessary to follow the steps shown here: 1. Back up all `NDB' databases in the cluster, using the `START BACKUP' command in the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client (see *Note mysql-cluster-backup::). 2. At some later point, prior to restoring the cluster, make a backup of the `mysql.ndb_binlog_index' table. It is probably simplest to use *Note `mysqldump': mysqldump. for this task. Also back up the binary log files at this time. This backup should be updated regularly--perhaps even hourly--depending on your needs. 3. (_Catastrophic failure or error occurs_.) 4. Locate the last known good backup. 5. Clear the data node file systems (using *Note `ndbd': mysql-cluster-programs-ndbd. `--initial' or, in MySQL Cluster NDB 7.0 and later, *Note `ndbmtd': mysql-cluster-programs-ndbmtd. `--initial'). *Note*: MySQL Cluster Disk Data tablespace and log files are not removed by `--initial'. You must delete these manually. 6. Use *Note `DROP TABLE': drop-table. or *Note `TRUNCATE TABLE': truncate-table. with the `mysql.ndb_binlog_index' table. 7. Execute *Note `ndb_restore': mysql-cluster-programs-ndb-restore, restoring all data. You must include the `--restore_epoch' option when you run *Note `ndb_restore': mysql-cluster-programs-ndb-restore, so that the `ndb_apply_status' table is populated correctly. (See *Note mysql-cluster-programs-ndb-restore::, for more information.) 8. Restore the `ndb_binlog_index' table from the output of *Note `mysqldump': mysqldump. and restore the binary log files from backup, if necessary. 9. Find the epoch applied most recently--that is, the maximum `epoch' column value in the `ndb_apply_status' table--as the user variable `@LATEST_EPOCH' (emphasized): SELECT _@LAST_EPOCH_:=MAX(epoch) FROM mysql.ndb_apply_status; 10. Find the latest binary log file (`@FIRST_FILE') and position (`Position' column value) within this file that correspond to `@LATEST_EPOCH' in the `ndb_binlog_index' table: SELECT Position, _@FIRST_FILE_:=File FROM mysql.ndb_binlog_index WHERE epoch > _@LAST_EPOCH_ ORDER BY epoch ASC LIMIT 1; 11. Using *Note `mysqlbinlog': mysqlbinlog, replay the binary log events from the given file and position up to the point of the failure. (See *Note mysqlbinlog::.) See also *Note point-in-time-recovery::, for more information about the binary log, replication, and incremental recovery.  File: manual.info, Node: mysql-cluster-replication-multi-master, Next: mysql-cluster-replication-conflict-resolution, Prev: mysql-cluster-replication-backups, Up: mysql-cluster-replication 17.6.10 MySQL Cluster Replication: Multi-Master and Circular Replication ------------------------------------------------------------------------ Beginning with MySQL 5.1.18, it is possible to use MySQL Cluster in multi-master replication, including circular replication between a number of MySQL Clusters. *Note*: Prior to MySQL 5.1.18, multi-master replication including circular replication was not supported with MySQL Cluster replication. This was because log events created in a particular MySQL Cluster were wrongly tagged with the server ID of the master rather than the server ID of the originating server. Circular replication example In the next few paragraphs we consider the example of a replication setup involving three MySQL Clusters numbered 1, 2, and 3, in which Cluster 1 acts as the replication master for Cluster 2, Cluster 2 acts as the master for Cluster 3, and Cluster 3 acts as the master for Cluster 1. Each cluster has two SQL nodes, with SQL nodes A and B belonging to Cluster 1, SQL nodes C and D belonging to Cluster 2, and SQL nodes E and F belonging to Cluster 3. Circular replication using these clusters is supported as long as the following conditions are met: * The SQL nodes on all masters and slaves are the same * All SQL nodes acting as replication masters and slaves are started using the `--log-slave-updates' option This type of circular replication setup is shown in the following diagram: MySQL Cluster circular replication scheme in which all master SQL nodes are also slaves. In this scenario, SQL node A in Cluster 1 replicates to SQL node C in Cluster 2; SQL node C replicates to SQL node E in Cluster 3; SQL node E replicates to SQL node A. In other words, the replication line (indicated by the red arrows in the diagram) directly connects all SQL nodes used as replication masters and slaves. It is also possible to set up circular replication in such a way that not all master SQL nodes are also slaves, as shown here: MySQL Cluster circular replication scheme in which all master SQL nodes are not also necessarily slaves. In this case, different SQL nodes in each cluster are used as replication masters and slaves. However, you must _not_ start any of the SQL nodes using `--log-slave-updates' (see the description of this option for more information). This type of circular replication scheme for MySQL Cluster, in which the line of replication (again indicated by the red arrows in the diagram) is discontinuous, should be possible, but it should be noted that it has not yet been thoroughly tested and must therefore still be considered experimental. *Important*: Beginning with MySQL 5.1.24, you should execute the following statement before starting circular replication: mysql> SET GLOBAL SLAVE_EXEC_MODE = 'IDEMPOTENT'; This is necessary to suppress duplicate-key and other errors that otherwise break circular replication in MySQL Cluster. `IDEMPOTENT' mode is also required for multi-master replication when using MySQL Cluster. (Bug#31609) See `slave_exec_mode', for more information. Using NDB-native backup and restore to initialize a slave MySQL Cluster When setting up circular replication, it is possible to initialize the slave cluster by using the management client `BACKUP' command on one MySQL Cluster to create a backup and then applying this backup on another MySQL Cluster using *Note `ndb_restore': mysql-cluster-programs-ndb-restore. However, this does not automatically create binary logs on the second MySQL Cluster's SQL node acting as the replication slave. In order to cause the binary logs to be created, you must issue a *Note `SHOW TABLES': show-tables. statement on that SQL node; this should be done prior to running *Note `START SLAVE': start-slave. This is a known issue which we intend to address in a future release. Multi-master failover example In this section, we discuss failover in a multi-master MySQL Cluster replication setup with three MySQL Clusters having server IDs 1, 2, and 3. In this scenario, Cluster 1 replicates to Clusters 2 and 3; Cluster 2 also replicates to Cluster 3. This relationship is shown here: Multi-master MySQL Cluster replication setup, with three MySQL Clusters In other words, data replicates from Cluster 1 to Cluster 3 through 2 different routes: directly, and by way of Cluster 2. Not all MySQL servers taking part in multi-master replication must act as both master and slave, and a given MySQL Cluster might use different SQL nodes for diffferent replication channels. Such a case is shown here: Multi-master MySQL Cluster replication setup, detail with MySQL Servers MySQL servers acting as replication slaves must be run with the `--log-slave-updates' option. Which *Note `mysqld': mysqld. processes require this option is also shown in the preceding diagram. *Note*: Using the `--log-slave-updates' option has no effect on servers not being run as replication slaves. The need for failover arises when one of the replicating clusters goes down. In this example, we consider the case where Cluster 1 is lost to service, and so Cluster 3 loses 2 sources of updates from Cluster 1. Because replication between MySQL Clusters is asynchronous, there is no guarantee that Cluster 3's updates originating directly from Cluster 1 are more recent than those received through Cluster 2. You can handle this by ensuring that Cluster 3 catches up to Cluster 2 with regard to updates from Cluster 1. In terms of MySQL servers, this means that you need to replicate any outstanding updates from MySQL server C to server F. On server C, perform the following queries: mysqlC> SELECT @latest:=MAX(epoch) -> FROM mysql.ndb_apply_status -> WHERE server_id=1; mysqlC> SELECT -> @file:=SUBSTRING_INDEX(File, '/', -1), -> @pos:=Position -> FROM mysql.ndb_binlog_index -> WHERE orig_epoch >= @latest -> AND orig_server_id = 1 -> ORDER BY epoch ASC LIMIT 1; Copy over the values for @FILE and @POS manually from server C to server F (or have your application perform the equivalent). Then, on server F, execute the following *Note `CHANGE MASTER TO': change-master-to. statement: mysqlF> CHANGE MASTER TO -> MASTER_HOST = 'serverC' -> MASTER_LOG_FILE='@file', -> MASTER_LOG_POS=@pos; Once this has been done, you can issue a *Note `START SLAVE': start-slave. statement on MySQL server F, and any missing updates originating from server B will be replicated to server F. Beginning with MySQL Cluster MySQL Cluster NDB 6.1.29, MySQL Cluster NDB 6.3.31, MySQL Cluster NDB 7.0.11, and MySQL Cluster NDB 7.1.0, the *Note `CHANGE MASTER TO': change-master-to. statement also supports an `IGNORE_SERVER_IDS' option which takes a comma-separated list of server IDs and causes events originating from the corresponding servers to be ignored. For more information, see *Note change-master-to::, and *Note show-slave-status::.  File: manual.info, Node: mysql-cluster-replication-conflict-resolution, Prev: mysql-cluster-replication-multi-master, Up: mysql-cluster-replication 17.6.11 MySQL Cluster Replication Conflict Resolution ----------------------------------------------------- When using a replication setup involving multiple masters (including circular replication), it is possible that different masters may try to update the same row on the slave with different data. Conflict resolution in MySQL Cluster Replication provides a means of resolving such conflicts by permitting a user-defined resolution column to be used to determine whether or not an update to the row on a given master should be applied on the slave. (This column is sometimes referred to as a `timestamp' column, even though this column' type cannot be *Note `TIMESTAMP': datetime, as explained later in this section.) Different methods can be used to compare resolution column values on the slave when conflicts occur, as explained later in this section; the method used can be set on a per-table basis. *Important*: Conflict resolution as described in this section is always applied on a row-by-row basis rather than a transactional basis. In addition, it is the application's responsibility to ensure that the resolution column is correctly populated with relevant values, so that the resolution function can make the appropriate choice when determining whether to apply an update. Requirements Preparations for conflict resolution must be made on both the master and the slave. These tasks are described in the following list: * On the master writing the binlogs, you must determine which columns are sent (all columns or only those that have been updated). This is done for the MySQL Server as a whole by applying the *Note `mysqld': mysqld. startup option `--ndb-log-updated-only' (described later in this section) or on a per-table basis by entries in the `mysql.ndb_replication' table (see *Note mysql-cluster-ndb-replication-table::). *Note*: If you are replicating tables with very large columns (such as *Note `TEXT': blob. or *Note `BLOB': blob. columns), `--ndb-log-updated-only' can also be useful for reducing the size of the master and slave binary logs and avoiding possible replication failures due to exceeding `max_allowed_packet'. See *Note replication-features-max-allowed-packet::, for more information about this issue. * On the slave, you must determine which type of conflict resolution to apply (`latest timestamp wins', `same timestamp wins', or none). This is done using the `mysql.ndb_replication' system table, on a per-table basis (see *Note mysql-cluster-ndb-replication-table::). We refer to the column used for determining updates as a `timestamp' column, but the data type of this column is never *Note `TIMESTAMP': datetime.; rather, its data type should be *Note `INT': numeric-types. (*Note `INTEGER': numeric-types.) or *Note `BIGINT': numeric-types. This `timestamp' column should also be `UNSIGNED' and `NOT NULL'. Master column control We can see update operations in terms of `before' and `after' images--that is, the states of the table before and after the update is applied. Normally, when updating a table with a primary key, the `before' image is not of great interest; however, when we need to determine on a per-update basis whether or not to use the updated values on a replication slave, we need to make sure that both images are written to the master's binary log. This is done with the `--ndb-log-update-as-write' option for *Note `mysqld': mysqld, as described later in this section. *Important*: Whether logging of complete rows or of updated columns only is done is decided when the MySQL server is started, and cannot be changed online; you must either restart *Note `mysqld': mysqld, or start a new *Note `mysqld': mysqld. instance with different logging options. * Logging Full or Partial Rows (`--ndb-log-updated-only' Option) * Options for ndb_log_updated_only *Version Introduced* 5.1.19-ndb-6.3.0 *Command-Line Format* `--ndb-log-updated-only' *Option-File Format* `ndb_log_updated_only' *Variable Name* `ndb_log_updated_only' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `boolean' *Default* `ON' For purposes of conflict resolution, there are two basic methods of logging rows, as determined by the setting of the `--ndb-log-updated-only' option for *Note `mysqld': mysqld.: * Log complete rows * Log only column data that has been updated--that is, column data whose value has been set, regardless of whether or not this value was actually changed. This is the default behavior. It is usually sufficient--and more efficient--to log updated columns only; however, if you need to log full rows, you can do so by setting `--ndb-log-updated-only' to `0' or `OFF'. * `--ndb-log-update-as-write' Option: Logging Changed Data as Updates * Options for ndb-log-update-as-write *Version Introduced* 5.1.19-ndb-6.3.0, 5.1.22-ndb-6.2.5 *Command-Line Format* `--ndb-log-update-as-write' *Option-File Format* `ndb-log-update-as-write' *Variable Name* `ndb_log_update_as_write' *Variable Scope* Global *Dynamic Variable* Yes *Permitted Values * *Type* `boolean' *Default* `ON' The setting of the MySQL Server's `--ndb-log-update-as-write' option determines whether logging is performed with or without the `before' image. Because conflict resolution is done in the MySQL Server's update handler, it is necessary to control logging on the master such that updates are updates and not writes; that is, such that updates are treated as changes in existing rows rather than the writing of new rows (even though these replace existing rows). This option is turned on by default; in other words, updates are treated as writes. (That is, updates are by default written as `write_row' events in the binary log, rather than as `update_row' events.) To turn off the option, start the master *Note `mysqld': mysqld. with `--ndb-log-update-as-write=0' or `--ndb-log-update-as-write=OFF'. Conflict resolution control Conflict resolution is usually enabled on the server where conflicts can occur. Like logging method selection, it is enabled by entries in the `mysql.ndb_replication' table. The `ndb_replication' system table To enable conflict resolution, it is necessary to create an `ndb_replication' table in the `mysql' system database on the master, the slave, or both, depending on the conflict resolution type and method to be employed. This table is used to control logging and conflict resolution functions on a per-table basis, and has one row per table involved in replication. `ndb_replication' is created and filled with control information on the server where the conflict is to be resolved. In a simple master-slave setup where data can also be changed locally on the slave this will typically be the slave. In a more complex master-master (2-way) replication schema this will usually be all of the masters involved. Each row in `mysql.ndb_replication' corresponds to a table being replicated, and specifies how to log and resolve conflicts (that is, which conflict resolution function, if any, to use) for that table. The definition of the `mysql.ndb_replication' table is shown here: CREATE TABLE mysql.ndb_replication ( db VARBINARY(63), table_name VARBINARY(63), server_id INT UNSIGNED, binlog_type INT UNSIGNED, conflict_fn VARBINARY(128), PRIMARY KEY USING HASH (db, table_name, server_id) ) ENGINE=NDB PARTITION BY KEY(db,table_name); The columns in this table are described in the following list: * `db' The name of the database containing the table to be replicated. * `table_name' The name of the table to be replicated. * `server_id' The unique server ID of the MySQL instance (SQL node) where the table resides. * `binlog_type' The type of binary logging to be employed. This is determined as shown in the following table: Value Internal Value Description 0 `NBT_DEFAULT' Use server default 1 `NBT_NO_LOGGING' Do not log this table in the binary log 2 `NBT_UPDATED_ONLY' Only updated attributes are logged 3 `NBT_FULL' Log full row, even if not updated (MySQL server default behavior) 4 `NBT_USE_UPDATE' (For generating `NBT_UPDATED_ONLY_USE_UPDATE' and `NBT_FULL_USE_UPDATE' values only--not intended for separate use) 5 [_Not used_] -- 6 `NBT_UPDATED_ONLY_USE_UPDATE'Use updated attributes, even if (equal to values are unchanged `NBT_UPDATED_ONLY | NBT_USE_UPDATE') 7 `NBT_FULL_USE_UPDATE'Use full row, even if values are (equal to `NBT_FULL unchanged | NBT_USE_UPDATE') * `conflict_fn' The conflict resolution function to be applied. This function must be specified as one of the following: . * `NDB$OLD(COLUMN_NAME') If the value of COLUMN_NAME is the same on both the master and the slave, then the update is applied; otherwise, the update is not applied on the slave and an exception is written to the log. This is illustrated by the following pseudocode: if (MASTER_OLD_COLUMN_VALUE == SLAVE_CURRENT_COLUMN_VALUE) perform_update(); else log_exception(); This function can be used for `same value wins' conflict resolution. This type of conflict resolution ensures that updates are not applied on the slave from the wrong master. *Important*: The column value from the master's `before' image is used by this function. This conflict resolution function is available beginning with MySQL Cluster NDB 6.3.4. * `NDB$MAX(COLUMN_NAME') If the `timestamp' column value for a given row coming from the master is higher than that on the slave, it is applied; otherwise it is not applied on the slave. This is illustrated by the following pseudocode: if (MASTER_NEW_COLUMN_VALUE > SLAVE_CURRENT_COLUMN_VALUE) perform_update(); This function can be used for `greatest timestamp wins' conflict resolution. This type of conflict resolution ensures that, in the event of a conflict, the version of the row that was most recently updated is the version that persists. *Important*: The column value from the master's `after' image is used by this function. This conflict resolution function is available beginning with MySQL Cluster NDB 6.3.0. * `NDB$MAX_DELETE_WIN(COLUMN_NAME') This is a variation on `NDB$MAX()'. Due to the fact that no timestamp is available for a delete operation, a delete using `NDB$MAX()' is in fact processed as `NDB$OLD'. Howver, for some use cases, this is not optimal. For `NDB$MAX_DELETE_WIN()', if the `timestamp' column value for a given row adding or updating an existing row coming from the master is higher than that on the slave, it is applied. However, delete operations are treated as always having the higher value. This is illustrated in the following pseudocode: if ( (MASTER_NEW_COLUMN_VALUE > SLAVE_CURRENT_COLUMN_VALUE) || OPERATION.TYPE == "delete") perform_update(); This function can be used for `greatest timestamp, delete wins' conflict resolution. This type of conflict resolution ensures that, in the event of a conflict, the version of the row that was deleted or (otherwise) most recently updated is the version that persists. This conflict resolution function is available beginning with MySQL Cluster NDB 6.3.31 and MySQL Cluster NDB 7.0.11. *Note*: As with `NDB$MAX()', the column value from the master's `after' image is the value used by this function. * `NULL' Indicates that conflict resolution is not to be used for the corresponding table. Status information Beginning with MySQL Cluster NDB 6.3.3, a server status variable `Ndb_conflict_fn_max' provides a count of the number of times that a row was not applied on the current SQL node due to `greatest timestamp wins' conflict resolution since the last time that *Note `mysqld': mysqld. was started. Beginning with MySQL Cluster NDB 6.3.4, the number of times that a row was not applied as the result of `same timestamp wins' conflict resolution on a given *Note `mysqld': mysqld. since the last time it was restarted is given by the global status variable `Ndb_conflict_fn_old'. In addition to incrementing `Ndb_conflict_fn_old', the primary key of the row that was not used is inserted into an _exceptions table_, as explained later in this section. Additional requirements for `Same timestamp wins' conflict resolution To use the `NDB$OLD()' conflict resolution function, it is also necessary to create an exceptions table corresponding to each *Note `NDB': mysql-cluster. table for which this type of conflict resolution is to be employed. The name of this table is that of the table for which `same timestamp wins' conflict resolution is to be applied, with the string `$EX' appended. (For example, if the name of the original table is `mytable', the name of the corresponding exception table name should be `mytable$EX'.) This table is created as follows: CREATE TABLE ORIGINAL_TABLE$EX ( server_id INT UNSIGNED, master_server_id INT UNSIGNED, master_epoch BIGINT UNSIGNED, count INT UNSIGNED, ORIGINAL_TABLE_PK_COLUMNS, [ADDITIONAL_COLUMNS,] PRIMARY KEY(server_id, master_server_id, master_epoch, count) ) ENGINE=NDB; The first four columns are required. Following these columns, the columns making up the original table's primary key should be copied in the order in which they are used to define the primary key of the original table. *Note*: The names of the first four columns and the columns matching the original table's primary key columns are not critical; however, we suggest for reasons of clarity and consistency, that you use the names shown here for the `server_id', `master_server_id', `master_epoch', and `count' columns, and that you use the same names as in the original table for the columns matching those in the original table's primary key. The data types for the columns duplicating the primary key columns of the original table should be the same as for (or larger than) the original columns. Additional columns may optionally be defined following these columns, but not before any of them; any such extra columns cannot be `NOT NULL'. The exception table's primary key must be defined as shown. The exception table must use the *Note `NDB': mysql-cluster. storage engine. An example of use for `NDB$OLD()' and an exception table is given later in this section. *Important*: The `mysql.ndb_replication' table is read when a data table is set up for replication, so the row corresponding to a table to be replicated must be inserted into `mysql.ndb_replication' _before_ the table to be replicated is created. Examples The following examples assume that you have already a working MySQL Cluster replication setup, as described in *Note mysql-cluster-replication-preparation::, and *Note mysql-cluster-replication-starting::. * `NDB$MAX()' example Suppose you wish to enable `greatest timestamp wins' conflict resolution on table `test.t1', using column `mycol' as the `timestamp'. This can be done using the following steps: 1. Make sure that you have started the master *Note `mysqld': mysqld. with `--ndb-log-update-as-write=OFF'. 2. On the master, perform this *Note `INSERT': insert. statement: INSERT INTO mysql.ndb_replication VALUES ('test', 't1', 0, NULL, 'NDB$MAX(mycol)'); Inserting a 0 into the `server_id' indicates that all SQL nodes accessing this table should use conflict resolution. If you want to use conflict resolution on a specific *Note `mysqld': mysqld. only, use the actual server ID. Inserting `NULL' into the `binlog_type' column has the same effect as inserting 0 (`NBT_DEFAULT'); the server default is used. 3. Create the `test.t1' table: CREATE TABLE test.t1 ( COLUMNS mycol INT UNSIGNED, COLUMNS ) ENGINE=NDB; Now, when updates are done on this table, conflict resolution is applied, and the version of the row having the greatest value for `mycol' is written to the slave. *Note*: Other `binlog_type' options--such as `NBT_UPDATED_ONLY_USE_UPDATE' should be used to control logging on the master using the `ndb_replication' table rather than by using command-line options. * `NDB$OLD()' example Suppose an *Note `NDB': mysql-cluster. table such as the one defined here is being replicated, and you wish to enable `same timestamp wins' conflict resolution for updates to this table: CREATE TABLE test.t2 ( a INT UNSIGNED NOT NULL, b CHAR(25) NOT NULL, COLUMNS, mycol INT UNSIGNED NOT NULL, COLUMNS, PRIMARY KEY pk (a, b) ) ENGINE=NDB; The following steps are required, in the order shown: 1. First--and _prior_ to creating `test.t2'--you must insert a row into the `mysql.ndb_replication' table, as shown here: INSERT INTO mysql.ndb_replication VALUES ('test', 't2', 0, NULL, 'NDB$OLD(mycol)'); Possible values for the `binlog_type' column are shown earlier in this section. The value `'NDB$OLD(mycol)'' should be inserted into the `conflict_fn' column. 2. Create an appropriate exceptions table for `test.t2'. The table creation statement shown here includes all required columns; any additional columns must be declared following these columns, and before the definition of the table's primary key. CREATE TABLE test.t2$EX ( server_id SMALLINT UNSIGNED, master_server_id INT UNSIGNED, master_epoch BIGINT UNSIGNED, count BIGINT UNSIGNED, a INT UNSIGNED NOT NULL, b CHAR(25) NOT NULL, [ADDITIONAL_COLUMNS,] PRIMARY KEY(server_id, master_server_id, master_epoch, count) ) ENGINE=NDB; 3. Create the table `test.t2' as shown previously. These steps must be followed for every table for which you wish to perform conflict resolution using `NDB$OLD()'. For each such table, there must be a corresponding row in `mysql.ndb_replication', and there must be an exceptions table in the same database as the table being replicated.  File: manual.info, Node: mysql-cluster-news, Prev: mysql-cluster-replication, Up: mysql-cluster 17.7 Changes in MySQL Cluster NDB 6.X and 7.X ============================================= * Menu: * mysql-cluster-news-7-2:: Changes in MySQL Cluster NDB 7.2 * mysql-cluster-news-7-1:: Changes in MySQL Cluster NDB 7.1 * mysql-cluster-news-7-0:: Changes in MySQL Cluster NDB 7.0 * mysql-cluster-news-6-3:: Changes in MySQL Cluster NDB 6.3 * mysql-cluster-news-6-2:: Changes in MySQL Cluster NDB 6.2 * mysql-cluster-news-6-1:: Changes in MySQL Cluster NDB 6.1 * mysql-cluster-news-series:: Release Series Changelogs: MySQL Cluster NDB 6.X and 7.X This section contains changelog information for MySQL Cluster releases that use versions 6.1, 6.2, 6.3, 7.0, and 7.1 of the *Note `NDBCLUSTER': mysql-cluster. storage engine. *Note*: Version 7.0 of the *Note `NDBCLUSTER': mysql-cluster. storage engine was previously known as `NDB 6.4'. For more information, see *Note mysql-cluster-news-7-0::. Each MySQL Cluster release is based on a mainline MySQL 5.1 release and a particular version of the *Note `NDBCLUSTER': mysql-cluster. storage engine, as shown in the version string returned by executing `SELECT VERSION()' in the *Note `mysql': mysql. client, or by executing the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client `SHOW' or `STATUS' command; for more information, see *Note mysql-cluster::. For general information about features added in MySQL Cluster, see *Note mysql-cluster-development::. For a complete list of all bugfixes and feature changes in MySQL Cluster, please refer to the changelog section for each individual MySQL Cluster release. An overview of features added in MySQL 5.1 not specific to MySQL Cluster can be found here: *Note mysql-nutshell::. For a complete list of all bugfixes and features changes made in MySQL 5.1 that are not specific to MySQL Cluster, see *Note news-5-1-x::. This section contains changelogs for individual MySQL Cluster NDB 6.X and 7.X releases. For long-format changelogs covering each MySQL Cluster NDB 6.X and 7.X series, see *Note mysql-cluster-news-series::.  File: manual.info, Node: mysql-cluster-news-7-2, Next: mysql-cluster-news-7-1, Prev: mysql-cluster-news, Up: mysql-cluster-news 17.7.1 Changes in MySQL Cluster NDB 7.2 --------------------------------------- * Menu: * mysql-cluster-news-5-1-51-ndb-7-2-0:: Changes in MySQL Cluster NDB 7.2.0 (5.1.51-ndb-7.2.0) (11 April 2011 Development Milestone) This section contains change history information for MySQL Cluster releases based on version 7.2 of the *Note `NDBCLUSTER': mysql-cluster. storage engine, currently in development. For an overview of new features added in MySQL Cluster NDB 7.2, see *Note mysql-cluster-development-5-1-ndb-7-2::.  File: manual.info, Node: mysql-cluster-news-5-1-51-ndb-7-2-0, Prev: mysql-cluster-news-7-2, Up: mysql-cluster-news-7-2 17.7.1.1 Changes in MySQL Cluster NDB 7.2.0 (5.1.51-ndb-7.2.0) (11 April 2011 Development Milestone) .................................................................................................... MySQL Cluster NDB 7.2.0 is a new development preview release of MySQL Cluster, incorporating several new features in the *Note `NDBCLUSTER': mysql-cluster. storage engine for testing and user feedback. Obtaining MySQL Cluster NDB 7.2 MySQL Cluster NDB 7.2.0 source code and binaries can be obtained from `http://dev.mysql.com/downloads/cluster/'. This release also incorporates all bugfixes and changes made in previous MySQL Cluster releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.51 (see *Note news-5-1-51::). *Functionality added or changed:* * *Performance*: Added support for pushing down joins to the NDB kernel for parallel execution across the data nodes, which can speed up execution of joins across *Note `NDB': mysql-cluster. tables by a factor of 20 or more in some cases. Some restrictions apply on the types of joins that can be optimized in this way; in particular, columns to be joined must use exactly the same data type, and cannot be any of the *Note `BLOB': blob. or *Note `TEXT': blob. types. In addition, columns to be joined must be part of a table index or primary key. Support for this feature can be enabled or diabled using the `ndb_join_pushdown' server system variable (enabled by default); see the description of this variable for more information and examples. As part of this improvement, the status variables `Ndb_pushed_queries_defined', `Ndb_pushed_queries_dropped', `Ndb_pushed_queries_executed', and `Ndb_pushed_reads' also been introduced for monitoring purposes. You can also see whether a given join is pushed down using *Note `EXPLAIN': explain. In addition, several new counters relating to push-down join performance have been added to the *Note `counters': mysql-cluster-ndbinfo-counters. table in the *Note `ndbinfo': mysql-cluster-ndbinfo. database. For more information, see the descriptions of the status variables previously mentioned. * *Important Change*: The default values for a number of MySQL Cluster data node configuration parameters have changed, in order to provide more resiliency to environmental issues and better handling of some potential failure scenarios, and to perform more reliably with increases in memory and other resource requirements brought about by recent improvements in join handling by *Note `NDB': mysql-cluster. The affected parameters are listed here: * `HeartbeatIntervalDbDb': Default increased from 1500 ms to 5000 ms. * `ArbitrationTimeout': Default increased from 3000 ms to 7500 ms. * `TimeBetweenEpochsTimeout': Now effectively disabled by default (default changed from 4000 ms to 0). * `SharedGlobalMemory': Default increased from 20 MB to 128 MB. * `MaxParallelScansPerFragment': Default increased from 32 to 256. In addition, when `MaxNoOfLocalScans' is not specified, the value computed for it automatically has been increased by a factor of 4 (that is, to 4 times `MaxNoOfConcurrentScans', times the number of data nodes in the cluster). * *Important Change*: MySQL user privileges can now be distributed automatically across all MySQL servers (SQL nodes) connected to the same MySQL Cluster. Previously, each MySQL Server's user privilege tables were required to use the *Note `MyISAM': myisam-storage-engine. storage engine, which meant that a user account and its associated privileges created on one SQL node were not available on any other SQL node without manual intervention. MySQL Cluster now provides an SQL script file `ndb_dist_priv.sql' that can be found in `share/mysql' under the MySQL installation directory; loading this script creates a stored procedure `mysql_cluster_move_privileges' that can be used following initial installation to convert the privilege tables to the *Note `NDB': mysql-cluster. storage engine, so that any time a MySQL user account is created, dropped, or has its privileges updated on any SQL node, the changes take effect immediately on all other MySQL servers attached to the cluster. Note that you may need to execute *Note `FLUSH PRIVILEGES': flush. on any SQL nodes with connected MySQL clients (or to disconnect and then reconnect the clients) in order for those clients to be able to see the changes in privileges. Once `mysql_cluster_move_privileges' has been executed successfully, all MySQL user privileges are distributed across all connected MySQL Servers. MySQL Servers that join the cluster after this automatically participate in the privilege distribution. `ndb_dist_priv.sql' also provides stored routines that can be used to verify that the privilege tables have been distributed successfully, and to perform other tasks. For more information, see *Note mysql-cluster-privilege-distribution::.  File: manual.info, Node: mysql-cluster-news-7-1, Next: mysql-cluster-news-7-0, Prev: mysql-cluster-news-7-2, Up: mysql-cluster-news 17.7.2 Changes in MySQL Cluster NDB 7.1 --------------------------------------- * Menu: * mysql-cluster-news-5-1-56-ndb-7-1-16:: Changes in MySQL Cluster NDB 7.1.16 (5.1.56-ndb-7.1.16) (Not yet released) * mysql-cluster-news-5-1-56-ndb-7-1-15:: Changes in MySQL Cluster NDB 7.1.15 (5.1.56-ndb-7.1.15) (Not yet released) * mysql-cluster-news-5-1-56-ndb-7-1-14:: Changes in MySQL Cluster NDB 7.1.14 (5.1.56-ndb-7.1.14) (24 May 2011) * mysql-cluster-news-5-1-56-ndb-7-1-13:: Changes in MySQL Cluster NDB 7.1.13 (5.1.56-ndb-7.1.13) (26 April 2011) * mysql-cluster-news-5-1-51-ndb-7-1-12:: Changes in MySQL Cluster NDB 7.1.12 (5.1.51-ndb-7.1.12) (04 April 2011) * mysql-cluster-news-5-1-51-ndb-7-1-11:: Changes in MySQL Cluster NDB 7.1.11 (5.1.51-ndb-7.1.11) (25 February 2011) * mysql-cluster-news-5-1-51-ndb-7-1-10:: Changes in MySQL Cluster NDB 7.1.10 (5.1.51-ndb-7.1.10) (26 January 2011) * mysql-cluster-news-5-1-51-ndb-7-1-9a:: Changes in MySQL Cluster NDB 7.1.9a (5.1.51-ndb-7.1.9a) (18 November 2010) * mysql-cluster-news-5-1-51-ndb-7-1-9:: Changes in MySQL Cluster NDB 7.1.9 (5.1.51-ndb-7.1.9) (08 November 2010) * mysql-cluster-news-5-1-47-ndb-7-1-8:: Changes in MySQL Cluster NDB 7.1.8 (5.1.47-ndb-7.1.8) (08 October 2010) * mysql-cluster-news-5-1-47-ndb-7-1-7:: Changes in MySQL Cluster NDB 7.1.7 (5.1.47-ndb-7.1.7) (03 September 2010) * mysql-cluster-news-5-1-47-ndb-7-1-6:: Changes in MySQL Cluster NDB 7.1.6 (5.1.47-ndb-7.1.6) (16 August 2010) * mysql-cluster-news-5-1-47-ndb-7-1-5:: Changes in MySQL Cluster NDB 7.1.5 (5.1.47-ndb-7.1.5) (25 June 2010) * mysql-cluster-news-5-1-44-ndb-7-1-4b:: Changes in MySQL Cluster NDB 7.1.4b (5.1.44-ndb-7.1.4b) (18 June 2010) * mysql-cluster-news-5-1-44-ndb-7-1-4a:: Changes in MySQL Cluster NDB 7.1.4a (5.1.44-ndb-7.1.4a) (Not released) * mysql-cluster-news-5-1-44-ndb-7-1-4:: Changes in MySQL Cluster NDB 7.1.4 (5.1.44-ndb-7.1.4) (31 May 2010) * mysql-cluster-news-5-1-44-ndb-7-1-3:: Changes in MySQL Cluster NDB 7.1.3 (5.1.44-ndb-7.1.3) (12 April 2010 General Availability) * mysql-cluster-news-5-1-41-ndb-7-1-2:: Changes in MySQL Cluster NDB 7.1.2 (5.1.41-ndb-7.1.2) (02 March 2010) * mysql-cluster-news-5-1-41-ndb-7-1-1:: Changes in MySQL Cluster NDB 7.1.1 (5.1.41-ndb-7.1.1) (01 February 2010 beta) * mysql-cluster-news-5-1-39-ndb-7-1-0:: Changes in MySQL Cluster NDB 7.1.0 (5.1.39-ndb-7.1.0) (Not released alpha) This section contains change history information for MySQL Cluster releases based on version 7.1 of the *Note `NDBCLUSTER': mysql-cluster. storage engine. For an overview of new features added in MySQL Cluster NDB 7.1, see *Note mysql-cluster-development-5-1-ndb-7-1::.  File: manual.info, Node: mysql-cluster-news-5-1-56-ndb-7-1-16, Next: mysql-cluster-news-5-1-56-ndb-7-1-15, Prev: mysql-cluster-news-7-1, Up: mysql-cluster-news-7-1 17.7.2.1 Changes in MySQL Cluster NDB 7.1.16 (5.1.56-ndb-7.1.16) (Not yet released) ................................................................................... MySQL Cluster NDB 7.1.16 is a new release of MySQL Cluster, incorporating new features in the *Note `NDBCLUSTER': mysql-cluster. storage engine and fixing recently discovered bugs in MySQL Cluster NDB 7.1.15 and previous MySQL Cluster releases. Obtaining MySQL Cluster NDB 7.1 The latest MySQL Cluster NDB 7.1 binaries for supported platforms can be obtained from `http://dev.mysql.com/downloads/cluster/'. Source code for the latest MySQL Cluster NDB 7.1 release can be obtained from the same location. You can also access the MySQL Cluster NDB 7.1 development source tree at `https://code.launchpad.net/~mysql/mysql-server/mysql-cluster-7.1'. This release also incorporates all bugfixes and changes made in previous MySQL Cluster releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.56 (see *Note news-5-1-56::). *Bugs fixed:* * The maximum effective value for the `OverloadLimit' configuration parameter was limited by the value of `SendBufferMemory'. Now the value set for `OverloadLimit' is used correctly, up to this parameter's stated maximum (4G). (Bug #12712109)  File: manual.info, Node: mysql-cluster-news-5-1-56-ndb-7-1-15, Next: mysql-cluster-news-5-1-56-ndb-7-1-14, Prev: mysql-cluster-news-5-1-56-ndb-7-1-16, Up: mysql-cluster-news-7-1 17.7.2.2 Changes in MySQL Cluster NDB 7.1.15 (5.1.56-ndb-7.1.15) (Not yet released) ................................................................................... MySQL Cluster NDB 7.1.15 is a new release of MySQL Cluster, incorporating new features in the *Note `NDBCLUSTER': mysql-cluster. storage engine and fixing recently discovered bugs in MySQL Cluster NDB 7.1.14 and previous MySQL Cluster releases. Obtaining MySQL Cluster NDB 7.1 The latest MySQL Cluster NDB 7.1 binaries for supported platforms can be obtained from `http://dev.mysql.com/downloads/cluster/'. Source code for the latest MySQL Cluster NDB 7.1 release can be obtained from the same location. You can also access the MySQL Cluster NDB 7.1 development source tree at `https://code.launchpad.net/~mysql/mysql-server/mysql-cluster-7.1'. This release also incorporates all bugfixes and changes made in previous MySQL Cluster releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.56 (see *Note news-5-1-56::). *Functionality added or changed:* * Added the `MaxDMLOperationsPerTransaction' data node configuration parameter, which can be used to limit the number of DML operations used by a transaction; if the transaction requires more than this many DML operations, the transaction is aborted. (Bug #12589613) *Bugs fixed:* * When global checkpoint indexes were written with no intervening end-of-file or megabyte border markers, this could sometimes lead to a situation in which the end of the redo log was mistakenly regarded as being between these GCIs, so that if the restart of a data node took place before the start of the next redo log was overwritten, the node encountered an `Error while reading the REDO log'. (Bug #12653993, Bug #61500) See also Bug #56961. * Restarting a *Note `mysqld': mysqld. during a rolling upgrade with data nodes running a mix of old and new versions of the MySQL Cluster software caused the *Note `mysqld': mysqld. to run in read-only mode. (Bug #12651364, Bug #61498) * Error reporting has been improved for cases in which API nodes are unable to connect due to apparent unavailability of node IDs. (Bug #12598398) * Error messages for `Failed to convert connection' transporter registration problems were inspecific. (Bug #12589691) * Under certain rare circumstances, a data node process could fail with Signal 11 during a restart. This was due to uninitialized variables in the `QMGR' kernel block. (Bug #12586190) * Multiple management servers were unable to detect one another until all nodes had fully started. As part of the fix for this issue, two new status values `RESUME' and `CONNECTED' can be reported for management nodes in the output of the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client `SHOW' command (see *Note mysql-cluster-mgm-client-commands::). Two corresponding status values `NDB_MGM_NODE_STATUS_RESUME' and `NDB_MGM_NODE_STATUS_CONNECTED' are also added to the list of possible values for an `ndb_mgm_node_status' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-node-status.html) data structure in the MGM API. (Bug #12352191, Bug #48301) * Handling of the `MaxNoOfTables' and `MaxNoOfAttributes' configuration parameters was not consistent in all parts of the *Note `NDB': mysql-cluster. kernel, and were only strictly enforced by the `DBDICT' and `SUMA' kernel blocks. This could lead to problems when tables could be created but not replicated. Now these parameters are treated by `SUMA' and `DBDICT' as suggested maximums rather than hard limits, as they are elsewhere in the *Note `NDB': mysql-cluster. kernel. (Bug #61684) * It was not possible to shut down a management node while one or more data nodes were stopped (for whatever reason). This issue was a regression introduced in MySQL Cluster NDB 7.0.24 and MySQL Cluster NDB 7.1.13. (Bug #61607) See also Bug #61147. * *Cluster API*: Applications that included the header file `ndb_logevent.h' could not be built using the Microsoft Visual Studio C compiler or the Oracle (Sun) Studio C compiler due to empty struct definitions. (Bug #12678971) * *Cluster API*: Within a transaction, after creating, executing, and closing a scan, calling `NdbTransaction::refresh()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndbtransaction-methods.html#ndb-ndbtransaction-refresh) after creating and executing but not closing a second scan caused the application to crash. (Bug #12646659)  File: manual.info, Node: mysql-cluster-news-5-1-56-ndb-7-1-14, Next: mysql-cluster-news-5-1-56-ndb-7-1-13, Prev: mysql-cluster-news-5-1-56-ndb-7-1-15, Up: mysql-cluster-news-7-1 17.7.2.3 Changes in MySQL Cluster NDB 7.1.14 (5.1.56-ndb-7.1.14) (24 May 2011) .............................................................................. MySQL Cluster NDB 7.1.14 is a new release of MySQL Cluster, incorporating new features in the *Note `NDBCLUSTER': mysql-cluster. storage engine and fixing recently discovered bugs in MySQL Cluster NDB 7.1.13 and previous MySQL Cluster releases. Obtaining MySQL Cluster NDB 7.1 The latest MySQL Cluster NDB 7.1 binaries for supported platforms can be obtained from `http://dev.mysql.com/downloads/cluster/'. Source code for the latest MySQL Cluster NDB 7.1 release can be obtained from the same location. You can also access the MySQL Cluster NDB 7.1 development source tree at `https://code.launchpad.net/~mysql/mysql-server/mysql-cluster-7.1'. This release also incorporates all bugfixes and changes made in previous MySQL Cluster releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.56 (see *Note news-5-1-56::). *Bugs fixed:* * The internal `Ndb_getinaddr()' function has been rewritten to use `getaddrinfo()' instead of `my_gethostbyname_r()' (which is removed in a later version of the MySQL Server). (Bug #12542120) * *Note `mysql_upgrade': mysql-upgrade. failed when performing an online upgrade from MySQL Cluster NDB 7.1.8 or an earlier release to MySQL Cluster NDB 7.1.9 or later in which the SQL nodes were upgraded before the data nodes. This issue could occur during any online upgrade or downgrade where one or more *Note `ndbinfo': mysql-cluster-ndbinfo. tables had more, fewer, or differing columns between the two versions, and when the data nodes were not upgraded before the SQL nodes. For more information, see *Note mysql-cluster-upgrade-downgrade-compatibility-7.x::. (Bug #11885602, Bug #12581895, Bug #12581954) * Two unused test files in `storage/ndb/test/sql' contained incorrect versions of the GNU Lesser General Public License. The files and the directory containing them have been removed. (Bug #11810156) See also Bug #11810224. * Error 1302 gave the wrong error message (`Out of backup record'). This has been corrected to `A backup is already running'. (Bug #11793592) * When using two management servers, issuing in an *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client connected to one management server a `STOP' command for stopping the other management server caused Error 2002 (`Stop failed ... Send to process or receive failed.: Permanent error: Application error'), even though the `STOP' command actually succeeded, and the second *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. was shut down. (Bug #61147) * In *Note `ndbmtd': mysql-cluster-programs-ndbmtd, a node connection event is detected by a `CMVMI' thread which sends a `CONNECT_REP' signal to the `QMGR' kernel block. In a few isolated circumstances, a signal might be transfered to `QMGR' directly by the *Note `NDB': mysql-cluster. transporter before the `CONNECT_REP' signal actually arrived. This resulted in reports in the error log with status `Temporary error, restart node', and the message `Internal program error'. (Bug #61025) * Renaming a table having *Note `BLOB': blob. or *Note `TEXT': blob. columns (or both) to another database caused the SQL node to crash, and the table to become inaccessible afterwards. (Bug #60484) * Under heavy loads with many concurrent inserts, temporary failures in transactions could occur (and were misreported as being due to *Note `NDB': mysql-cluster. Error 899 `Rowid already allocated'). As part of the fix for this issue, *Note `NDB': mysql-cluster. Error 899 has been reclassified as an internal error, rather than as a temporary transaction error. (Bug #56051, Bug #11763354) * *Disk Data*: Accounting for `MaxNoOfOpenFiles' was incorrect with regard to to data files in MySQL Cluster Disk Data tablespaces. This could lead to a crash when `MaxNoOfOpenFiles' was exceeded. (Bug #12581213) * *Cluster Replication*: Operations that updated unique keys of *Note `NDB': mysql-cluster. tables could cause duplicate key errors when trying to execute the binary log. (Previously, row events in the binary log were ordered according to the partitioning of the base table, which could differ in order within the epoch for that in which they were executed. To keep this from happening, unique keys are now updated in deferred mode, meaning that all table rows are updated before any unique indexes are checked. Thus, the order of the row updates is no longer important. You should be aware that deferring constraint checking in this way is currently supported only by *Note `NDB': mysql-cluster, and thus only for replication between NDB tables on both the master and the slave. You cannot replicate updates of unique keys successfully when replicating from *Note `NDB': mysql-cluster. to a different storage engine such as *Note `MyISAM': myisam-storage-engine. or *Note `InnoDB': innodb-storage-engine. (Bug #47952, Bug #11756082)  File: manual.info, Node: mysql-cluster-news-5-1-56-ndb-7-1-13, Next: mysql-cluster-news-5-1-51-ndb-7-1-12, Prev: mysql-cluster-news-5-1-56-ndb-7-1-14, Up: mysql-cluster-news-7-1 17.7.2.4 Changes in MySQL Cluster NDB 7.1.13 (5.1.56-ndb-7.1.13) (26 April 2011) ................................................................................ MySQL Cluster NDB 7.1.13 is a new release of MySQL Cluster, incorporating new features in the *Note `NDBCLUSTER': mysql-cluster. storage engine and fixing recently discovered bugs in MySQL Cluster NDB 7.1.12 and previous MySQL Cluster releases. Obtaining MySQL Cluster NDB 7.1 The latest MySQL Cluster NDB 7.1 binaries for supported platforms can be obtained from `http://dev.mysql.com/downloads/cluster/'. Source code for the latest MySQL Cluster NDB 7.1 release can be obtained from the same location. You can also access the MySQL Cluster NDB 7.1 development source tree at `https://code.launchpad.net/~mysql/mysql-server/mysql-cluster-7.1'. This release also incorporates all bugfixes and changes made in previous MySQL Cluster releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.56 (see *Note news-5-1-56::). *Functionality added or changed:* * It is now possible to add data nodes online to a running MySQL Cluster without performing a rolling restart of the cluster or starting data node processes with the `--nowait-nodes' option. This can be done by setting `Nodegroup = 65536' in the `config.ini' file for any data nodes that should be started at a later time, when first starting the cluster. (It was possible to set `NodeGroup' to this value previously, but the management server failed to start.) As part of this fix, a new data node configuration parameter `StartNoNodeGroupTimeout' has been added. When the management server sees that there are data nodes with no node group (that is, nodes for which `Nodegroup = 65536'), it waits `StartNoNodeGroupTimeout' milliseconds before treating these nodes as though they were listed with the `--nowait-nodes' option, and proceeds to start. For more information, see *Note mysql-cluster-online-add-node::. (Bug #11766167, Bug #59213) * A `config_generation' column has been added to the *Note `nodes': mysql-cluster-ndbinfo-nodes. table of the *Note `ndbinfo': mysql-cluster-ndbinfo. database. By checking this column, it is now possible to determine which version or versions of the MySQL Cluster configuration file are in effect on the data nodes. This information can be especially useful when performing a rolling restart of the cluster in order to update its configuration. *Bugs fixed:* * *Cluster API*: A unique index operation is executed in two steps: a lookup on an index table, and an operation on the base table. When the operation on the base table failed, while being executed in a batch with other operations that succeeded, this could lead to a hanging execute, eventually timing out with Error 4012 (`Request ndbd time-out, maybe due to high load or communication problems'). (Bug #12315582) * A memory leak in `LGMAN', that leaked 8 bytes of log buffer memory per 32k written, was introduced in MySQL Cluster NDB 7.0.9, effecting all MySQL Cluster NDB 7.1 releases as well as MySQL Cluster NDB 7.0.9 and later MySQL Cluster NDB 7.0 releases. (For example, when 128 MB log buffer memory was used, it was exhausted after writing 512 GB to the undo log.) This led to a GCP stop and data node failure. (Bug #60946) This regression was introduced by Bug #47966. * When using *Note `ndbmtd': mysql-cluster-programs-ndbmtd, a MySQL Cluster configured with 32 data nodes failed to start correctly. (Bug #60943) * When performing a TUP scan with locks in parallel, and with a highly concurrent load of inserts and deletions, the scan could sometimes fail to notice that a record had moved while waiting to acquire a lock on it, and so read the wrong record. During node recovery, this could lead to a crash of a node that was copying data to the node being started, and a possible forced shutdown of the cluster. * *Cluster API*: Performing interpreted operations using a unique index did not work correctly, because the interpret bit was kept when sending the lookup to the index table.  File: manual.info, Node: mysql-cluster-news-5-1-51-ndb-7-1-12, Next: mysql-cluster-news-5-1-51-ndb-7-1-11, Prev: mysql-cluster-news-5-1-56-ndb-7-1-13, Up: mysql-cluster-news-7-1 17.7.2.5 Changes in MySQL Cluster NDB 7.1.12 (5.1.51-ndb-7.1.12) (04 April 2011) ................................................................................ MySQL Cluster NDB 7.1.12 is a new release of MySQL Cluster, incorporating new features in the *Note `NDBCLUSTER': mysql-cluster. storage engine and fixing recently discovered bugs in MySQL Cluster NDB 7.1.11 and previous MySQL Cluster releases. Obtaining MySQL Cluster NDB 7.1 The latest MySQL Cluster NDB 7.1 binaries for supported platforms can be obtained from `http://dev.mysql.com/downloads/cluster/'. Source code for the latest MySQL Cluster NDB 7.1 release can be obtained from the same location. You can also access the MySQL Cluster NDB 7.1 development source tree at `https://code.launchpad.net/~mysql/mysql-server/mysql-cluster-7.1'. This release also incorporates all bugfixes and changes made in previous MySQL Cluster releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.51 (see *Note news-5-1-51::). *Functionality added or changed:* * Improved scaling of ordered index scans performance by removing a hard-coded limit (`MAX_PARALLEL_INDEX_SCANS_PER_FRAG') and making the number of `TUP' or `TUX' scans per fragment configurable by adding the `MaxParallelScansPerFragment' data node configuration parameter. (Bug #11769048) *Bugs fixed:* * *Important Change*: Formerly, the `--ndb-cluster-connection-pool' server option set a status variable as well as a system variable. The status variable has been removed as redundant. (Bug #60119) * A scan with a pushed condition (filter) using the `CommittedRead' lock mode could hang for a short interval when it was aborted when just as it had decided to send a batch. (Bug #11932525) * When aborting a multi-read range scan exactly as it was changing ranges in the local query handler, LQH could fail to detect it, leaving the scan hanging. (Bug #11929643) * Schema distribution did not take place for tables converted from another storage engine to *Note `NDB': mysql-cluster. using *Note `ALTER TABLE': alter-table.; this meant that such tables were not always visible to all SQL nodes attached to the cluster. (Bug #11894966) * A GCI value inserted by *Note `ndb_restore': mysql-cluster-programs-ndb-restore. `--restore_epoch' into the `ndb_apply_status' table was actually 1 less than the correct value. (Bug #11885852) * *Replication*: Error 1590 (`ER_SLAVE_INCIDENT') caused the slave to stop even when it was started with `--slave-skip-errors=1590'. (Bug #59889, Bug #11768580, Bug #11799671) * *Cluster Replication*: Filtering the binary log using `--binlog-ignore-db=mysql' caused epochs not to be logged as expected in the `ndb_apply_status' table. (Bug #11765707, Bug #58698) * Binary columns can now be used as key columns. Error reporting when trying to use unsupported column types has been improved. Updates for `DynamicObject (http://dev.mysql.com/doc/ndbapi/en/mccj-clusterj-dynamicobject.html#mccj-clusterj-dynamicobject)' persistent classes are now handled as expected. (Bug #11766757, Bug #59942) * ClusterJ incorrectly asked for the character set for a *Note `LONGVARBINARY': binary-varbinary. column with *Note `VARBINARY(256)': binary-varbinary. columns, leading to a VM crash caused by invalid memory access. (Bug #11766756, Bug #59941) * *Disk Data*: Limits imposed by the size of `SharedGlobalMemory' were not always enforced consistently with regard to Disk Data undo buffers and log files. This could sometimes cause a *Note `CREATE LOGFILE GROUP': create-logfile-group. or *Note `ALTER LOGFILE GROUP': alter-logfile-group. statement to fail for no apparent reason, or cause the log file group specified by `InitialLogFileGroup' not to be created when starting the cluster. (Bug #57317) * The optimizer sometimes requested ordered access from a storage engine when ordered access was not required. (Bug #57601, Bug #11764737)  File: manual.info, Node: mysql-cluster-news-5-1-51-ndb-7-1-11, Next: mysql-cluster-news-5-1-51-ndb-7-1-10, Prev: mysql-cluster-news-5-1-51-ndb-7-1-12, Up: mysql-cluster-news-7-1 17.7.2.6 Changes in MySQL Cluster NDB 7.1.11 (5.1.51-ndb-7.1.11) (25 February 2011) ................................................................................... MySQL Cluster NDB 7.1.11 is a new release of MySQL Cluster, incorporating new features in the *Note `NDBCLUSTER': mysql-cluster. storage engine and fixing recently discovered bugs in MySQL Cluster NDB 7.1.10 and previous MySQL Cluster releases. Obtaining MySQL Cluster NDB 7.1 The latest MySQL Cluster NDB 7.1 binaries for supported platforms can be obtained from `http://dev.mysql.com/downloads/cluster/'. Source code for the latest MySQL Cluster NDB 7.1 release can be obtained from the same location. You can also access the MySQL Cluster NDB 7.1 development source tree at `https://code.launchpad.net/~mysql/mysql-server/mysql-cluster-7.1'. This release also incorporates all bugfixes and changes made in previous MySQL Cluster releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.51 (see *Note news-5-1-51::). *Functionality added or changed:* * *Disk Data*: The *Note `INFORMATION_SCHEMA.TABLES': tables-table. table now provides disk usage as well as memory usage information for Disk Data tables. Also, *Note `INFORMATION_SCHEMA.PARTITIONS': partitions-table, formerly did not show any statistics for *Note `NDB': mysql-cluster. tables. Now the `TABLE_ROWS', `AVG_ROW_LENGTH', `DATA_LENGTH', `MAX_DATA_LENGTH', and `DATA_FREE' columns contain correct information for the table's partitions. * A new `--rewrite-database' option is added for *Note `ndb_restore': mysql-cluster-programs-ndb-restore, which makes it possible to restore to a database having a different name from that of the database in the backup. For more information, see *Note mysql-cluster-programs-ndb-restore::. (Bug #54327) * Added the `--lossy-conversions' option for *Note `ndb_restore': mysql-cluster-programs-ndb-restore, which makes it possible to enable attribute demotion when restoring a MySQL Cluster from an *Note `NDB': mysql-cluster. native backup. For additional information about type conversions currently supported by MySQL Cluster for attribute promotion and demotion, see *Note replication-features-different-data-types::. * Made it possible to enable multi-threaded building of ordered indexes during initial restarts, using the new `TwoPassInitialNodeRestartCopy' data node configuration parameter. *Bugs fixed:* * This issue affects all previous MySQL Cluster NDB 7.1 releases. (Bug #60045) * *Note `ndb_restore `--rebuild-indexes'': mysql-cluster-programs-ndb-restore. caused multi-threaded index building to occur on the master node only. (Bug #59920) * Successive queries on the *Note `counters': mysql-cluster-ndbinfo-counters. table from the same SQL node returned unchanging results. To fix this issue, and to prevent similar issues from occurring in the future, *Note `ndbinfo': mysql-cluster-ndbinfo. tables are now excluded from the query cache. (Bug #59831) * When a *Note `CREATE TABLE': create-table. statement failed due to *Note `NDB': mysql-cluster. error 1224 (`Too many fragments'), it was not possible to create the table afterward unless either it had no ordered indexes, or a *Note `DROP TABLE': drop-table. statement was issued first, even if the subsequent *Note `CREATE TABLE': create-table. was valid and should otherwise have succeeded. (Bug #59756) See also Bug #59751. * When attempting to create a table on a MySQL Cluster with many standby data nodes (setting `Nodegroup=65536' in `config.ini' for the nodes that should wait, starting the nodes that should start immediately with the `--nowait-nodes' option, and using the *Note `CREATE TABLE': create-table. statement's `MAX_ROWS' option), *Note `mysqld': mysqld. miscalculated the number of fragments to use. This caused the *Note `CREATE TABLE': create-table. to fail. *Note*: The *Note `CREATE TABLE': create-table. failure caused by this issue in turn prevented any further attempts to create the table, even if the table structure was simplified or changed in such a way that the attempt should have succeeded. This `ghosting' issue is handled in BUG#59756. (Bug #59751) * *Note `NDB': mysql-cluster. sometimes treated a simple (not unique) ordered index as unique. (Bug #59519) * The logic used in determining whether to collapse a range to a simple equality was faulty. In certain cases, this could cause *Note `NDB': mysql-cluster. to treat a range as if it were a primary key lookup when determining the query plan to be used. Although this did not affect the actual result returned by the query, it could in such cases result in inefficient execution of queries due to the use of an inappropriate query plan. (Bug #59517) * When a query used multiple references to or instances of the same physical tables, *Note `NDB': mysql-cluster. failed to recognize these multiple instances as different tables; in such a case, *Note `NDB': mysql-cluster. could incorrectly use condition pushdown on a condition referring to these other instances to be pushed to the data nodes, even though the condition should have been rejected as unpushable, leading to invalid results. (Bug #58791) * *Cluster API*: When calling `NdbEventOperation::execute()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndbeventoperation-methods.html#ndb-ndbeventoperation-execute) during a node restart, it was possible to get a spurious error 711 (`System busy with node restart, schema operations not allowed when a node is starting'). (Bug #59723) * *Cluster API*: When an NDBAPI client application was waiting for more scan results after calling `NdbScanOperation::nextResult()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndbscanoperation-methods.html#ndb-ndbscanoperation-nextresult), the calling thread sometimes woke up even if no new batches for any fragment had arrived, which was unnecessary, and which could have a negative impact on the application's performance. (Bug #52298) * An `OUTER JOIN' query using `WHERE COLUMN IS NULL' could return an incorrect result. (Bug #58490, Bug #11765513)  File: manual.info, Node: mysql-cluster-news-5-1-51-ndb-7-1-10, Next: mysql-cluster-news-5-1-51-ndb-7-1-9a, Prev: mysql-cluster-news-5-1-51-ndb-7-1-11, Up: mysql-cluster-news-7-1 17.7.2.7 Changes in MySQL Cluster NDB 7.1.10 (5.1.51-ndb-7.1.10) (26 January 2011) .................................................................................. MySQL Cluster NDB 7.1.10 is a new release of MySQL Cluster, incorporating new features in the *Note `NDBCLUSTER': mysql-cluster. storage engine and fixing recently discovered bugs in MySQL Cluster NDB 7.1.9a and previous MySQL Cluster releases. Obtaining MySQL Cluster NDB 7.1 The latest MySQL Cluster NDB 7.1 binaries for supported platforms can be obtained from `http://dev.mysql.com/downloads/cluster/'. Source code for the latest MySQL Cluster NDB 7.1 release can be obtained from the same location. You can also access the MySQL Cluster NDB 7.1 development source tree at `https://code.launchpad.net/~mysql/mysql-server/mysql-cluster-7.1'. This release also incorporates all bugfixes and changes made in previous MySQL Cluster releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.51 (see *Note news-5-1-51::). *Functionality added or changed:* * *Important Change*: The following changes have been made with regard to the `TimeBetweenEpochsTimeout' data node configuration parameter: * The maximum possible value for this parameter has been increased from 32000 milliseconds to 256000 milliseconds. * Setting this parameter to zero now has the effect of disabling GCP stops caused by save timeouts, commit timeouts, or both. * The current value of this parameter and a warning are written to the cluster log whenever a GCP save takes longer than 1 minute or a GCP commit takes longer than 10 seconds. For more information, see *Note mysql-cluster-ndbd-definition-gcp-stop-errors::. (Bug #58383) * Added the `--skip-broken-objects' option for *Note `ndb_restore': mysql-cluster-programs-ndb-restore. This option causes *Note `ndb_restore': mysql-cluster-programs-ndb-restore. to ignore tables corrupted due to missing blob parts tables, and to continue reading from the backup file and restoring the remaining tables. (Bug #54613) See also Bug #51652. * Made it possible to exercise more direct control over handling of timeouts occurring when trying to flush redo logs to disk using two new data node configuration parameters `RedoOverCommitCounter' and `RedoOverCommitLimit', as well as the new API node configuration parameter `DefaultOperationRedoProblemAction', all added in this release. Now, when such timeouts occur more than a specified number of times for the flushing of a given redo log, any transactions that were to be written are instead aborted, and the operations contained in those transactions can be either re-tried or themselves aborted. For more information, see *Note mysql-cluster-redo-over-commit-handling::. * *Cluster Replication*: Added the `--ndb-log-apply-status' server option, which causes a replication slave to apply updates to the master's `mysql.ndb_apply_status' table to its own `ndb_apply_status' table using its own server ID in place of the master's server ID. This option can be useful in circular or chain replication setups when you need to track updates to `ndb_apply_status' as they propagate from one MySQL Cluster to the next in the circle or chain. * *Cluster API*: It is now possible to stop or restart a node even while other nodes are starting, using the MGM API `ndb_mgm_stop4()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-stop4.html) or `ndb_mgm_restart4()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-restart4.html) function, respectively, with the FORCE parameter set to 1. (Bug #58451) See also Bug #58319. *Bugs fixed:* * *Cluster API*: In some circumstances, very large *Note `BLOB': blob. read and write operations in MySQL Cluster applications can cause excessive resource usage and even exhaustion of memory. To fix this issue and to provide increased stability when performing such operations, it is now possible to set limits on the volume of *Note `BLOB': blob. data to be read or written within a given transaction in such a way that when these limits are exceeded, the current transaction implicitly executes any accumulated operations. This avoids an excessive buildup of pending data which can result in resource exhaustion in the NDB kernel. The limits on the amount of data to be read and on the amount of data to be written before this execution takes place can be configured separately. (In other words, it is now possible in MySQL Cluster to specify read batching and write batching that is specific to *Note `BLOB': blob. data.) These limits can be configured either on the NDB API level, or in the MySQL Server. On the NDB API level, four new methods are added to the `NdbTransaction' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndbtransaction.html#ndb-ndbtransaction) object. `getMaxPendingBlobReadBytes()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndbtransaction-methods.html#ndb-ndbtransaction-getmaxpendingblobreadbytes) and `setMaxPendingBlobReadBytes()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndbtransaction-methods.html#ndb-ndbtransaction-setmaxpendingblobreadbytes) can be used to get and to set, respectively, the maximum amount of *Note `BLOB': blob. data to be read that accumulates before this implicit execution is triggered. `getMaxPendingBlobWriteBytes()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndbtransaction-methods.html#ndb-ndbtransaction-getmaxpendingblobwritebytes) and `setMaxPendingBlobWriteBytes()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndbtransaction-methods.html#ndb-ndbtransaction-setmaxpendingblobwritebytes) can be used to get and to set, respectively, the maximum volume of *Note `BLOB': blob. data to be written that accumulates before implicit execution occurs. For the MySQL server, two new options are added. The `--ndb-blob-read-batch-bytes' option sets a limit on the amount of pending *Note `BLOB': blob. data to be read before triggering implicit execution, and the `--ndb-blob-write-batch-bytes' option controls the amount of pending *Note `BLOB': blob. data to be written. These limits can also be set using the *Note `mysqld': mysqld. configuration file, or read and set within the *Note `mysql': mysql. client and other MySQL client applications using the corresponding server system variables. (Bug #59113) * Two related problems could occur with read-committed scans made in parallel with transactions combining multiple (concurrent) operations: 1. When committing a multiple-operation transaction that contained concurrent insert and update operations on the same record, the commit arrived first for the insert and then for the update. If a read-committed scan arrived between these operations, it could thus read incorrect data; in addition, if the scan read variable-size data, it could cause the data node to fail. 2. When rolling back a multiple-operation transaction having concurrent delete and insert operations on the same record, the abort arrived first for the delete operation, and then for the insert. If a read-committed scan arrived between the delete and the insert, it could incorrectly assume that the record should not be returned (in other words, the scan treated the insert as though it had not yet been committed). (Bug #59496) * On Windows platforms, issuing a `SHUTDOWN' command in the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client caused management processes that had been started with the `--nodaemon' option to exit abnormally. (Bug #59437) * A row insert or update followed by a delete operation on the same row within the same transaction could in some cases lead to a buffer overflow. (Bug #59242) See also Bug #56524. This regression was introduced by Bug #35208. * Data nodes configured with very large amounts (multiple gigabytes) of `DiskPageBufferMemory' failed during startup with NDB error 2334 (`Job buffer congestion'). (Bug #58945) See also Bug #47984. * The `FAIL_REP' signal, used inside the NDB kernel to declare that a node has failed, now includes the node ID of the node that detected the failure. This information can be useful in debugging. (Bug #58904) * When executing a full table scan caused by a `WHERE' condition using `UNIQUE_KEY IS NULL' in combination with a join, *Note `NDB': mysql-cluster. failed to close the scan. (Bug #58750) See also Bug #57481. * Issuing *Note `EXPLAIN EXTENDED': explain. for a query that would use condition pushdown could cause *Note `mysqld': mysqld. to crash. (Bug #58553, Bug #11765570) * In some circumstances, an SQL trigger on an *Note `NDB': mysql-cluster. table could read stale data. (Bug #58538) * During a node takeover, it was possible in some circumstances for one of the remaining nodes to send an extra transaction confirmation (`LQH_TRANSCONF') signal to the `DBTC' kernel block, conceivably leading to a crash of the data node trying to take over as the new transaction coordinator. (Bug #58453) * A query having multiple predicates joined by `OR' in the `WHERE' clause and which used the `sort_union' access method (as shown using *Note `EXPLAIN': explain.) could return duplicate rows. (Bug #58280) * Trying to drop an index while it was being used to perform scan updates caused data nodes to crash. (Bug #58277, Bug #57057) * When handling failures of multiple data nodes, an error in the construction of internal signals could cause the cluster's remaining nodes to crash. This issue was most likely to affect clusters with large numbers of data nodes. (Bug #58240) * The functions `strncasecmp' and `strcasecmp' were declared in `ndb_global.h' but never defined or used. The declarations have been removed. (Bug #58204) * Some queries of the form *Note `SELECT ... WHERE COLUMN IN (SUBQUERY)': select. against an *Note `NDB': mysql-cluster. table could cause *Note `mysqld': mysqld. to hang in an endless loop. (Bug #58163) * The number of rows affected by a statement that used a `WHERE' clause having an `IN' condition with a value list containing a great many elements, and that deleted or updated enough rows such that *Note `NDB': mysql-cluster. processed them in batches, was not computed or reported correctly. (Bug #58040) * MySQL Cluster failed to compile correctly on FreeBSD 8.1 due to misplaced `#include' statements. (Bug #58034) * A query using `BETWEEN' as part of a pushed-down `WHERE' condition could cause mysqld to hang or crash. (Bug #57735) * Data nodes no longer allocated all memory prior to being ready to exchange heartbeat and other messages with management nodes, as in NDB 6.3 and earlier versions of MySQL Cluster. This caused problems when data nodes configured with large amounts of memory failed to show as connected or showed as being in the wrong start phase in the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client even after making their initial connections to and fetching their configuration data from the management server. With this fix, data nodes now allocate all memory as they did in earlier MySQL Cluster versions. (Bug #57568) * In some circumstances, it was possible for *Note `mysqld': mysqld. to begin a new multi-range read scan without having closed a previous one. This could lead to exhaustion of all scan operation objects, transaction objects, or lock objects (or some combination of these) in *Note `NDB': mysql-cluster, causing queries to fail with such errors as `Lock wait timeout exceeded' or `Connect failure - out of connection objects'. (Bug #57481) See also Bug #58750. * Queries using `COLUMN IS' [`NOT'] `NULL' on a table with a unique index created with `USING HASH' on COLUMN always returned an empty result. (Bug #57032) * With `engine_condition_pushdown' enabled, a query using `LIKE' on an *Note `ENUM': enum. column of an *Note `NDB': mysql-cluster. table failed to return any results. This issue is resolved by disabling `engine_condition_pushdown' when performing such queries. (Bug #53360) * When a slash character (`/') was used as part of the name of an index on an *Note `NDB': mysql-cluster. table, attempting to execute a *Note `TRUNCATE TABLE': truncate-table. statement on the table failed with the error `Index not found', and the table was rendered unusable. (Bug #38914) * *Disk Data*: *Partitioning*: When using multi-threaded data nodes, an *Note `NDB': mysql-cluster. table created with a very large value for the `MAX_ROWS' option could--if this table was dropped and a new table with fewer partitions, but having the same table ID, was created--cause *Note `ndbmtd': mysql-cluster-programs-ndbmtd. to crash when performing a system restart. This was because the server attempted to examine each partition whether or not it actually existed. This issue is the same as that reported in Bug#45154, except that the current issue is specific to *Note `ndbmtd': mysql-cluster-programs-ndbmtd. instead of *Note `ndbd': mysql-cluster-programs-ndbd. (Bug #58638) * *Disk Data*: In certain cases, a race condition could occur when *Note `DROP LOGFILE GROUP': drop-logfile-group. removed the logfile group while a read or write of one of the effected files was in progress, which in turn could lead to a crash of the data node. (Bug #59502) * *Disk Data*: A race condition could sometimes be created when *Note `DROP TABLESPACE': drop-tablespace. was run concurrently with a local checkpoint; this could in turn lead to a crash of the data node. (Bug #59501) * *Disk Data*: Performing what should have been an online drop of a multi-column index was actually performed offline. (Bug #55618) * *Disk Data*: When at least one data node was not running, queries against the *Note `INFORMATION_SCHEMA.FILES': files-table. table took an excessive length of time to complete because the MySQL server waited for responses from any stopped nodes to time out. Now, in such cases, MySQL does not attempt to contact nodes which are not known to be running. (Bug #54199) * *Cluster Replication*: When a *Note `mysqld': mysqld. performing replication of a MySQL Cluster that uses *Note `ndbmtd': mysql-cluster-programs-ndbmtd. is forcibly disconnected (thus causing an `API_FAIL_REQ' signal to be sent), the `SUMA' kernel block iterates through all active subscriptions and disables them. If a given subscription has no more active users, then this subscription is also deactivated in the `DBTUP' kernel block. This process had no flow control, and when there were many subscriptions being deactivated (more than 512), this could cause an overflow in the short-time queue defined in the `DbtupProxy' class. The fix for this problem includes implementing proper flow control for this deactivation process and increasing the size of the short-time queue in `DbtupProxy'. (Bug #58693) * *Cluster API*: It was not possible to obtain the status of nodes accurately after an attempt to stop a data node using `ndb_mgm_stop()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-stop.html) failed without returning an error. (Bug #58319) * *Cluster API*: Attempting to read the same value (using `getValue()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndboperation-methods.html#ndb-ndboperation-getvalue)) more than 9000 times within the same transaction caused the transaction to hang when executed. Now when more reads are performed in this way than can be accommodated in a single transaction, the call to `execute()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndbtransaction-methods.html#ndb-ndbtransaction-execute) fails with a suitable error. (Bug #58110) * When building MySQL Cluster NDB 7.1 on Windows using `vcbuild' with parallelism set to 8, the `clusterj.jar' file was built before its dependencies, causing the build of this file to fail. (Bug #58563)  File: manual.info, Node: mysql-cluster-news-5-1-51-ndb-7-1-9a, Next: mysql-cluster-news-5-1-51-ndb-7-1-9, Prev: mysql-cluster-news-5-1-51-ndb-7-1-10, Up: mysql-cluster-news-7-1 17.7.2.8 Changes in MySQL Cluster NDB 7.1.9a (5.1.51-ndb-7.1.9a) (18 November 2010) ................................................................................... MySQL Cluster NDB 7.1.9a is a new release of MySQL Cluster which fixes a critical upgrade issue discovered in MySQL Cluster NDB 7.1.9 shortly after it was released. It is otherwise identical to MySQL Cluster NDB 7.1.9. Obtaining MySQL Cluster NDB 7.1 The latest MySQL Cluster NDB 7.1 binaries for supported platforms can be obtained from `http://dev.mysql.com/downloads/cluster/'. Source code for the latest MySQL Cluster NDB 7.1 release can be obtained from the same location. You can also access the MySQL Cluster NDB 7.1 development source tree at `https://code.launchpad.net/~mysql/mysql-server/mysql-cluster-7.1'. This release also incorporates all bugfixes and changes made in previous MySQL Cluster releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.51 (see *Note news-5-1-51::). *Bugs fixed:* * *Important Note*: Issuing an `ALL DUMP' command during a rolling upgrade to MySQL Cluster NDB 7.1.9 caused the cluster to crash. (Bug #58256) * *InnoDB Storage Engine*: *Packaging*: The *Note `InnoDB': innodb-storage-engine. plugin was not included in MySQL Cluster RPM packages. (Bug #58283) See also Bug #54912.  File: manual.info, Node: mysql-cluster-news-5-1-51-ndb-7-1-9, Next: mysql-cluster-news-5-1-47-ndb-7-1-8, Prev: mysql-cluster-news-5-1-51-ndb-7-1-9a, Up: mysql-cluster-news-7-1 17.7.2.9 Changes in MySQL Cluster NDB 7.1.9 (5.1.51-ndb-7.1.9) (08 November 2010) ................................................................................. MySQL Cluster NDB 7.1.9 is a new release of MySQL Cluster, incorporating new features in the *Note `NDBCLUSTER': mysql-cluster. storage engine and fixing recently discovered bugs in MySQL Cluster NDB 7.1.8 and previous MySQL Cluster releases. *Important*: A critical upgrade issue was discovered in MySQL Cluster NDB 7.1.9 shortly after release, causing it to be withdrawn and replaced with MySQL Cluster NDB 7.1.9a, which contains a fix for this issue. MySQL Cluster NDB 7.1.9a is otherwise identical to MySQL Cluster 7.1.9. See *Note mysql-cluster-news-5-1-51-ndb-7-1-9a::, for more information. Obtaining MySQL Cluster NDB 7.1 The latest MySQL Cluster NDB 7.1 binaries for supported platforms can be obtained from `http://dev.mysql.com/downloads/cluster/'. Source code for the latest MySQL Cluster NDB 7.1 release can be obtained from the same location. You can also access the MySQL Cluster NDB 7.1 development source tree at `https://code.launchpad.net/~mysql/mysql-server/mysql-cluster-7.1'. This release also incorporates all bugfixes and changes made in previous MySQL Cluster releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.51 (see *Note news-5-1-51::). *Functionality added or changed:* * *Important Change*: *InnoDB Storage Engine*: Building the MySQL Server with the *Note `InnoDB': innodb-storage-engine. plugin is now supported when building MySQL Cluster. For more information, see *Note mysql-cluster-installation::. (Bug #54912) See also Bug #58283. * *Important Change*: *Note `ndbd': mysql-cluster-programs-ndbd. now bypasses use of Non-Uniform Memory Access support on Linux hosts by default. If your system supports NUMA, you can enable it and override *Note `ndbd': mysql-cluster-programs-ndbd. use of interleaving by setting the `Numa' data node configuration parameter which is added in this release. See Defining Data Nodes: Realtime Performance Parameters, for more information. (Bug #57807) * A new *Note `diskpagebuffer': mysql-cluster-ndbinfo-diskpagebuffer. table, providing statistics on disk page buffer usage by Disk Data tables, is added to the *Note `ndbinfo': mysql-cluster-ndbinfo. information database. These statistics can be used to monitor performance of reads and writes on Disk Data tables, and to assist in the tuning of related parameters such as `DiskPageBufferMemory'. *Bugs fixed:* * *Packaging*: MySQL Cluster RPM distributions did not include a `shared-compat' RPM for the MySQL Server, which meant that MySQL applications depending on `libmysqlclient.so.15' (MySQL 5.0 and earlier) no longer worked. (Bug #38596) * On Windows, the angel process which monitors and (when necessary) restarts the data node process failed to spawn a new worker in some circumstances where the arguments vector contained extra items placed at its beginning. This could occur when the path to *Note `ndbd.exe': mysql-cluster-programs-ndbd. or *Note `ndbmtd.exe': mysql-cluster-programs-ndbmtd. contained one or more spaces. (Bug #57949) * The disconnection of an API or management node due to missed heartbeats led to a race condition which could cause data nodes to crash. (Bug #57946) * The method for calculating table schema versions used by schema transactions did not follow the established rules for recording schemas used in the `P0.SchemaLog' file. (Bug #57897) See also Bug #57896. * The `LQHKEYREQ' request message used by the local query handler when checking the major schema version of a table, being only 16 bits wide, could cause this check to fail with an `Invalid schema version' error (*Note `NDB': mysql-cluster. error code 1227). This issue occurred after creating and dropping (and re-creating) the same table 65537 times, then trying to insert rows into the table. (Bug #57896) See also Bug #57897. * Data nodes compiled with `gcc' 4.5 or higher crashed during startup. (Bug #57761) * Transient errors during a local checkpoint were not retried, leading to a crash of the data node. Now when such errors occur, they are retried up to 10 times if necessary. (Bug #57650) * *Note `ndb_restore': mysql-cluster-programs-ndb-restore. now retries failed transactions when replaying log entries, just as it does when restoring data. (Bug #57618) * The `SUMA' kernel block has a 10-element ring buffer for storing out-of-order `SUB_GCP_COMPLETE_REP' signals received from the local query handlers when global checkpoints are completed. In some cases, exceeding the ring buffer capacity on all nodes of a node group at the same time caused the node group to fail with an assertion. (Bug #57563) * During a GCP takeover, it was possible for one of the data nodes not to receive a `SUB_GCP_COMPLETE_REP' signal, with the result that it would report itself as `GCP_COMMITTING' while the other data nodes reported `GCP_PREPARING'. (Bug #57522) * Specifying a *Note `WHERE': select. clause of the form `RANGE1 OR RANGE2' when selecting from an *Note `NDB': mysql-cluster. table having a primary key on multiple columns could result in Error 4259 `Invalid set of range scan bounds' if RANGE2 started exactly where RANGE1 ended and the primary key definition declared the columns in a different order relative to the order in the table's column list. (Such a query should simply return all rows in the table, since any expression `VALUE < CONSTANT OR VALUE >= CONSTANT' is always true.) Example Suppose `t' is an *Note `NDB': mysql-cluster. table defined by the following *Note `CREATE TABLE': create-table. statement: CREATE TABLE t (a, b, PRIMARY KEY (b, a)) ENGINE NDB; This issue could then be triggered by a query such as this one: SELECT * FROM t WHERE b < 8 OR b >= 8; In addition, the order of the ranges in the `WHERE' clause was significant; the issue was not triggered, for example, by the query *Note `SELECT * FROM t WHERE b <= 8 OR b > 8': select. (Bug #57396) * A number of cluster log warning messages relating to deprecated configuration parameters contained spelling, formatting, and other errors. (Bug #57381) * The `MAX_ROWS' option for *Note `CREATE TABLE': create-table. was ignored, which meant that it was not possible to enable multi-threaded building of indexes. (Bug #57360) * A GCP stop is detected using 2 parameters which determine the maximum time that a global checkpoint or epoch can go unchanged; one of these controls this timeout for GCPs and one controls the timeout for epochs. Suppose the cluster is configured such that `TimeBetweenEpochsTimeout' is 100 ms but `HeartbeatIntervalDbDb' is 1500 ms. A node failure can be signalled after 4 missed heartbeats--in this case, 6000 ms. However, this would exceed `TimeBetweenEpochsTimeout', causing false detection of a GCP. To prevent this from happening, the configured value for `TimeBetweenEpochsTimeout' is automatically adjusted, based on the values of `HeartbeatIntervalDbDb' and `ArbitrationTimeout'. The current issue arose when the automatic adjustment routine did not correctly take into consideration the fact that, during cascading node-failures, several intervals of length `4 * (HeartbeatIntervalDBDB + ArbitrationTimeout)' may elapse before all node failures have internally been resolved. This could cause false GCP detection in the event of a cascading node failure. (Bug #57322) * Successive `CREATE NODEGROUP' and `DROP NODEGROUP' commands could cause *Note `mysqld': mysqld. processes to crash. (Bug #57164) * Queries using `WHERE VARCHAR_PK_COLUMN LIKE 'PATTERN%'' or `WHERE VARCHAR_PK_COLUMN LIKE 'PATTERN_'' against an *Note `NDB': mysql-cluster. table having a *Note `VARCHAR': char. column as its primary key failed to return all matching rows. (Bug #56853) * Aborting a native `NDB' backup in the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client using the `ABORT BACKUP' command did not work correctly when using *Note `ndbmtd': mysql-cluster-programs-ndbmtd, in some cases leading to a crash of the cluster. (Bug #56285) * When a data node angel process failed to fork off a new worker process (to replace one that had failed), the failure was not handled. This meant that the angel process either transformed itself into a worker process, or itself failed. In the first case, the data node continued to run, but there was no longer any angel to restart it in the event of failure, even with `StopOnError' set to 0. (Bug #53456) * *Partitioning*: Trying to use the same column more than once in the partitioning key when partitioning a table by `KEY' caused *Note `mysqld': mysqld. to crash. Such duplication of key columns is now expressly disallowed, and fails with an appropriate error. (Bug #53354, Bug #57924) * *Disk Data*: When performing online DDL on Disk Data tables, scans and moving of the relevant tuples were done in more or less random order. This fix causes these scans to be done in the order of the tuples, which should improve performance of such operations due to the more sequential ordering of the scans. (Bug #57848) See also Bug #57827. * *Disk Data*: Adding unique indexes to *Note `NDB': mysql-cluster. Disk Data tables could take an extremely long time. This was particularly noticeable when using *Note `ndb_restore `--rebuild-indexes'': mysql-cluster-programs-ndb-restore. (Bug #57827) * *Cluster Replication*: The `OPTION_ALLOW_BATCHING' bitmask had the same value as `OPTION_PROFILING'. This caused conflicts between using `--slave-allow-batching' and profiling. (Bug #57603) * *Cluster Replication*: Replication of *Note `SET': set. and *Note `ENUM': enum. columns represented using more than 1 byte (that is, *Note `SET': set. columns with more than 8 members and *Note `ENUM': enum. columns with more than 256 constants) between platforms using different endianness failed when using the row-based format. This was because columns of these types are represented internally using integers, but the internal functions used by MySQL to handle them treated them as strings. (Bug #52131) See also Bug #53528. * *Cluster API*: An application dropping a table at the same time that another application tried to set up a replication event on the same table could lead to a crash of the data node. The same issue could sometimes cause `NdbEventOperation::execute()' to hang. (Bug #57886) * *Cluster API*: An NDB API client program under load could abort with an assertion error in `TransporterFacade::remove_from_cond_wait_queue'. (Bug #51775) See also Bug #32708.  File: manual.info, Node: mysql-cluster-news-5-1-47-ndb-7-1-8, Next: mysql-cluster-news-5-1-47-ndb-7-1-7, Prev: mysql-cluster-news-5-1-51-ndb-7-1-9, Up: mysql-cluster-news-7-1 17.7.2.10 Changes in MySQL Cluster NDB 7.1.8 (5.1.47-ndb-7.1.8) (08 October 2010) ................................................................................. MySQL Cluster NDB 7.1.8 is a new release of MySQL Cluster, incorporating new features in the *Note `NDBCLUSTER': mysql-cluster. storage engine and fixing recently discovered bugs in MySQL Cluster NDB 7.1.7 and previous MySQL Cluster releases. Obtaining MySQL Cluster NDB 7.1 The latest MySQL Cluster NDB 7.1 binaries for supported platforms can be obtained from `http://dev.mysql.com/downloads/cluster/'. Source code for the latest MySQL Cluster NDB 7.1 release can be obtained from the same location. You can also access the MySQL Cluster NDB 7.1 development source tree at `https://code.launchpad.net/~mysql/mysql-server/mysql-cluster-7.1'. This release also incorporates all bugfixes and changes made in previous MySQL Cluster releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.47 (see *Note news-5-1-47::). *Functionality added or changed:* * *Note `mysqldump': mysqldump. as supplied with MySQL Cluster now has an `--add-drop-trigger' option which adds a *Note `DROP TRIGGER IF EXISTS': drop-trigger. statement before each dumped trigger definition. (Bug #55691) See also Bug #34325, Bug #11747863. * It is now possible using the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. management client or the MGM API to force a data node shutdown or restart even if this would force the shutdown or restart of the entire cluster. In the management client, this is implemented through the addition of the `-f' (force) option to the `STOP' and `RESTART' commands. For more information, see *Note mysql-cluster-mgm-client-commands::. The MGM API also adds two new methods for forcing such a node shutdown or restart; see `ndb_mgm_stop4()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-stop4.html), and `ndb_mgm_restart4()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-restart4.html), for more information about these methods. (Bug #54226) * *Cluster API*: The MGM API function `ndb_mgm_get_version()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-get-version.html), which was previously internal, has now been moved to the public API. This function can be used to get `NDB' storage engine and other version information from the management server. (Bug #51310) See also Bug #51273. *Bugs fixed:* * At startup, an *Note `ndbd': mysql-cluster-programs-ndbd. or *Note `ndbmtd': mysql-cluster-programs-ndbmtd. process creates directories for its file system without checking to see whether they already exist. Portability code added in MySQL Cluster NDB 7.0.18 and MySQL Cluster NDB 7.1.7 did not account for this fact, printing a spurious error message when a directory to be created already existed. This unneeded printout has been removed. (Bug #57087) * A data node can be shut down having completed and synchronized a given GCI X, while having written a great many log records belonging to the next GCI X + 1, as part of normal operations. However, when starting, completing, and synchronizing GCI X + 1, then the log records from original start must not be read. To make sure that this does not happen, the REDO log reader finds the last GCI to restore, scans forward from that point, and erases any log records that were not (and should never be) used. The current issue occurred because this scan stopped immediately as soon as it encountered an empty page. This was problematic because the REDO log is divided into several files; thus, it could be that there were log records in the beginning of the next file, even if the end of the previous file was empty. These log records were never invalidated; following a start or restart, they could be reused, leading to a corrupt REDO log. (Bug #56961) * An error in program flow in `ndbd.cpp' could result in data node shutdown routines being called multiple times. (Bug #56890) * Under certain rare conditions, attempting to start more than one *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. process simultaneously using the `--reload' option caused a race condition such that none of the *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. processes could start. (Bug #56844) * When distributing *Note `CREATE TABLE': create-table. and *Note `DROP TABLE': drop-table. operations among several SQL nodes attached to a MySQL Cluster. the `LOCK_OPEN' lock normally protecting *Note `mysqld': mysqld.'s internal table list is released so that other queries or DML statements are not blocked. However, to make sure that other DDL is not executed simultaneously, a global schema lock (implemented as a row-level lock by `NDB') is used, such that all operations that can modify the state of the *Note `mysqld': mysqld. internal table list also need to acquire this global schema lock. The *Note `SHOW TABLE STATUS': show-table-status. statement did not acquire this lock. (Bug #56841) * In certain cases, *Note `DROP DATABASE': drop-database. could sometimes leave behind a cached table object, which caused problems with subsequent DDL operations. (Bug #56840) * Memory pages used for `DataMemory', once assigned to ordered indexes, were not ever freed, even after any rows that belonged to the corresponding indexes had been deleted. (Bug #56829) * MySQL Cluster stores, for each row in each `NDB' table, a Global Checkpoint Index (GCI) which identifies the last committed transaction that modified the row. As such, a GCI can be thought of as a coarse-grained row version. Due to changes in the format used by `NDB' to store local checkpoints (LCPs) in MySQL Cluster NDB 6.3.11, it could happen that, following cluster shutdown and subsequent recovery, the GCI values for some rows could be changed unnecessarily; this could possibly, over the course of many node or system restarts (or both), lead to an inconsistent database. (Bug #56770) * When multiple SQL nodes were connected to the cluster and one of them stopped in the middle of a DDL operation, the *Note `mysqld': mysqld. process issuing the DDL timed out with the error `distributing TBL_NAME timed out. Ignoring'. (Bug #56763) * An online *Note `ALTER TABLE ... ADD COLUMN': alter-table. operation that changed the table schema such that the number of 32-bit words used for the bitmask allocated to each DML operation increased during a transaction in DML which was performed prior to DDL which was followed by either another DML operation or--if using replication--a commit, led to data node failure. This was because the data node did not take into account that the bitmask for the before-image was smaller than the current bitmask, which caused the node to crash. (Bug #56524) * On Windows, a data node refused to start in some cases unless the *Note `ndbd.exe': mysql-cluster-programs-ndbd. executable was invoked using an absolute rather than a relative path. (Bug #56257) * The text file `cluster_change_hist.txt' containing old MySQL Cluster changelog information was no longer being maintained, and so has been removed from the tree. (Bug #56116) * The failure of a data node during some scans could cause other data nodes to fail. (Bug #54945) * Exhausting the number of available commit-ack markers (controlled by the `MaxNoOfConcurrentTransactions' parameter) led to a data node crash. (Bug #54944) * When running a *Note `SELECT': select. on an *Note `NDB': mysql-cluster. table with *Note `BLOB': blob. or *Note `TEXT': blob. columns, memory was allocated for the columns but was not freed until the end of the *Note `SELECT': select. This could cause problems with excessive memory usage when dumping (using for example *Note `mysqldump': mysqldump.) tables with such columns and having many rows, large column values, or both. (Bug #52313) See also Bug #56488, Bug #50310. * *Cluster Replication*: When an SQL node starts, as part of setting up replication, it subscribes to data events from all data nodes using a `SUB_START_REQ' (subscription start request) signal. Atomicity of `SUB_START_REQ' is implemented such that, if any of the nodes returns an error, a `SUB_STOP_REQ' (subscription stop request) is sent to any nodes that replied with a `SUB_START_CONF' (subscription start confirmation). However, if all data nodes returned an error, `SUB_STOP_REQ' was not sent to any of them. This caused mysqld to hang when restarting (while waiting for a response), and subsequent data node restarts to hang as well. (Bug #56579) * *Cluster Replication*: When a *Note `mysqld': mysqld. process was shut down while it was still performing updates, it was possible for the entry containing binary log information for the final epoch preceding shutdown to be omitted from the `mysql.ndb_binlog_index' table. This could somtimes occur even during a normal shutdown of *Note `mysqld': mysqld. (Bug #55909) * *Cluster Replication*: The graceful shutdown of a data node in the master cluster could sometimes cause rows to be skipped when writing transactions to the binary log. Testing following an initial fix for this issue revealed an additional case where the graceful shutdown of a data node was not handled properly. The current fix addresses this case. (Bug #55641) See also Bug #18538. * *Cluster API*: The MGM API functions `ndb_mgm_stop()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-stop.html) and `ndb_mgm_restart()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-restart.html) set the error code and message without first checking whether the management server handle was `NULL', which could lead to fatal errors in MGM API applications that depended on these functions. (Bug #57089) * *Cluster API*: The MGM API function `ndb_mgm_get_version()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-get-version.html) did not set the error message before returning with an error. With this fix, it is now possible to call `ndb_mgm_get_latest_error()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-get-latest-error.html) after a failed call to this function such that `ndb_mgm_get_latest_error()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-get-latest-error.html) returns an error number and error message, as expected of MGM API calls. (Bug #57088)  File: manual.info, Node: mysql-cluster-news-5-1-47-ndb-7-1-7, Next: mysql-cluster-news-5-1-47-ndb-7-1-6, Prev: mysql-cluster-news-5-1-47-ndb-7-1-8, Up: mysql-cluster-news-7-1 17.7.2.11 Changes in MySQL Cluster NDB 7.1.7 (5.1.47-ndb-7.1.7) (03 September 2010) ................................................................................... MySQL Cluster NDB 7.1.7 is a new release of MySQL Cluster, incorporating new features in the *Note `NDBCLUSTER': mysql-cluster. storage engine and fixing recently discovered bugs in MySQL Cluster NDB 7.1.6 and previous MySQL Cluster releases. Obtaining MySQL Cluster NDB 7.1 The latest MySQL Cluster NDB 7.1 binaries for supported platforms can be obtained from `http://dev.mysql.com/downloads/cluster/'. Source code for the latest MySQL Cluster NDB 7.1 release can be obtained from the same location. You can also access the MySQL Cluster NDB 7.1 development source tree at `https://code.launchpad.net/~mysql/mysql-server/mysql-cluster-7.1'. This release also incorporates all bugfixes and changes made in previous MySQL Cluster releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.47 (see *Note news-5-1-47::). *Functionality added or changed:* * *Important Change*: More finely-grained control over restart-on-failure behavior is provided with two new data node configuration parameters `MaxStartFailRetries' and `StartFailRetryDelay'. `MaxStartFailRetries' limits the total number of retries made before giving up on starting the data node; `StartFailRetryDelay' sets the number of seconds between retry attempts. These parameters are used only if `StopOnError' is set to 0. For more information, see *Note mysql-cluster-ndbd-definition::. (Bug #54341) *Bugs fixed:* * *Important Change*: It is no longer possible to make a dump of the *Note `ndbinfo': mysql-cluster-ndbinfo. database using *Note `mysqldump': mysqldump. (Bug #54316) * *Note `ndb_restore': mysql-cluster-programs-ndb-restore. always reported 0 for the `GCPStop' (end point of the backup). Now it provides useful binary log position and epoch information. (Bug #56298) * The `LockExecuteThreadToCPU' configuration parameter was not handled correctly for CPU ID values greater than 255. (Bug #56185) * Following a failure of the master data node, the new master sometimes experienced a race condition which caused the node to terminate with a GcpStop error. (Bug #56044) * Trying to create a table having a *Note `BLOB': blob. or *Note `TEXT': blob. column with `DEFAULT ''' failed with the error `Illegal null attribute'. (An empty default is allowed and ignored by *Note `MyISAM': myisam-storage-engine.; *Note `NDB': mysql-cluster. should do the same.) (Bug #55121) * *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. `--nodaemon' logged to the console in addition to the configured log destination. (Bug #54779) * The warning `MaxNoOfExecutionThreads (#) > LockExecuteThreadToCPU count (#), this could cause contention' could be logged when running *Note `ndbd': mysql-cluster-programs-ndbd, even though the condition described can occur only when using *Note `ndbmtd': mysql-cluster-programs-ndbmtd. (Bug #54342) * Startup messages previously written by *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. to `stdout' are now written to the cluster log instead when `LogDestination' is set. (Bug #47595) * The graceful shutdown of a data node could sometimes cause transactions to be aborted unnecessarily. (Bug #18538) See also Bug #55641. * *Cluster Replication*: The graceful shutdown of a data node in the master cluster could sometimes cause rows to be skipped when writing transactions to the binary log, leading to an inconsistent slave cluster. (Bug #55641) See also Bug #18538. * *Cluster Replication*: Specifying the `--expire_logs_days' option when there were old binary logs to delete caused SQL nodes to crash on startup. (Bug #41751)  File: manual.info, Node: mysql-cluster-news-5-1-47-ndb-7-1-6, Next: mysql-cluster-news-5-1-47-ndb-7-1-5, Prev: mysql-cluster-news-5-1-47-ndb-7-1-7, Up: mysql-cluster-news-7-1 17.7.2.12 Changes in MySQL Cluster NDB 7.1.6 (5.1.47-ndb-7.1.6) (16 August 2010) ................................................................................ MySQL Cluster NDB 7.1.6 is a new release of MySQL Cluster, incorporating new features in the *Note `NDBCLUSTER': mysql-cluster. storage engine and fixing recently discovered bugs in MySQL Cluster NDB 7.1.5 and previous MySQL Cluster releases. Obtaining MySQL Cluster NDB 7.1 The latest MySQL Cluster NDB 7.1 binaries for supported platforms can be obtained from `http://dev.mysql.com/downloads/cluster/'. Source code for the latest MySQL Cluster NDB 7.1 release can be obtained from the same location. You can also access the MySQL Cluster NDB 7.1 development source tree at `https://code.launchpad.net/~mysql/mysql-server/mysql-cluster-7.1'. This release also incorporates all bugfixes and changes made in previous MySQL Cluster releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.47 (see *Note news-5-1-47::). *Functionality added or changed:* * Added the `DictTrace' data node configuration parameter, for use in debugging *Note `NDB': mysql-cluster. code. For more information, see *Note mysql-cluster-ndbd-definition::. (Bug #55963) * Added the `--server-id-bits' option for mysqld and mysqlbinlog. For *Note `mysqld': mysqld, the `--server-id-bits' option indicates the number of least significant bits within the 32-bit server ID which actually identify the server. Indicating that the server ID uses less than 32 bits permits the remaining bits to be used for other purposes by NDB API applications using the Event API and `OperationOptions::AnyValue'. For *Note `mysqlbinlog': mysqlbinlog, the `--server-id-bits' option tells *Note `mysqlbinlog': mysqlbinlog. how to interpret the server IDs in the binary log when the binary log was written by a *Note `mysqld': mysqld. having its `server_id_bits' set to less than the maximum (32). (Bug #52305) *Bugs fixed:* * *Cluster API*: *Important Change*: The poll and select calls made by the MGM API were not interrupt-safe; that is, a signal caught by the process while waiting for an event on one or more sockets returned error -1 with `errno' set to EINTR. This caused problems with MGM API functions such as `ndb_logevent_get_next()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-logevent-get-next.html) and `ndb_mgm_get_status2()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-get-status2.html). To fix this problem, the internal `ndb_socket_poller::poll()' function has been made EINTR-safe. The old version of this function has been retained as `poll_unsafe()', for use by those parts of NDB that do not need the EINTR-safe version of the function. (Bug #55906) * The TCP configuration parameters `HostName1' and `HostName2' were not displayed in the output of *Note `ndb_config': mysql-cluster-programs-ndb-config. `--configinfo'. (Bug #55839) * When another data node failed, a given data node `DBTC' kernel block could time out while waiting for `DBDIH' to signal commits of pending transactions, leading to a crash. Now in such cases the timeout generates a prinout, and the data node continues to operate. (Bug #55715) * Starting *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. with `--config-cache=0' caused it to leak memory. (Bug #55205) * The `configure.js' option `WITHOUT_DYNAMIC_PLUGINS=TRUE' was ignored when building MySQL Cluster for Windows using `CMake'. Among the effects of this issue was that `CMake' attempted to build the `InnoDB' storage engine as a plugin (`.DLL' file) even though the `InnoDB Plugin' is not currently supported by MySQL Cluster. (Bug #54913) * It was possible for a *Note `DROP DATABASE': drop-database. statement to remove *Note `NDB': mysql-cluster. hidden blob tables without removing the parent tables, with the result that the tables, although hidden to MySQL clients, were still visible in the output of *Note `ndb_show_tables': mysql-cluster-programs-ndb-show-tables. but could not be dropped using *Note `ndb_drop_table': mysql-cluster-programs-ndb-drop-table. (Bug #54788) * An excessive number of timeout warnings (normally used only for debugging) were written to the data node logs. (Bug #53987) * *Disk Data*: As an optimization when inserting a row to an empty page, the page is not read, but rather simply initialized. However, this optimzation was performed in all cases when an empty row was inserted, even though it should have been done only if it was the first time that the page had been used by a table or fragment. This is because, if the page had been in use, and then all records had been released from it, the page still needed to be read to learn its log sequence number (LSN). This caused problems only if the page had been flushed using an incorrect LSN and the data node failed before any local checkpoint was completed--which would removed any need to apply the undo log, hence the incorrect LSN was ignored. The user-visible result of the incorrect LSN was that it caused the data node to fail during a restart. It was perhaps also possible (although not conclusively proven) that this issue could lead to incorrect data. (Bug #54986) * *Cluster API*: Calling `NdbTransaction::refresh()' did not update the timer for `TransactionInactiveTimeout'. (Bug #54724)  File: manual.info, Node: mysql-cluster-news-5-1-47-ndb-7-1-5, Next: mysql-cluster-news-5-1-44-ndb-7-1-4b, Prev: mysql-cluster-news-5-1-47-ndb-7-1-6, Up: mysql-cluster-news-7-1 17.7.2.13 Changes in MySQL Cluster NDB 7.1.5 (5.1.47-ndb-7.1.5) (25 June 2010) .............................................................................. MySQL Cluster NDB 7.1.5 is a new release of MySQL Cluster, incorporating new features in the *Note `NDBCLUSTER': mysql-cluster. storage engine and fixing recently discovered bugs in MySQL Cluster NDB 7.1.4 and previous MySQL Cluster releases. Obtaining MySQL Cluster NDB 7.1 The latest MySQL Cluster NDB 7.1 binaries for supported platforms can be obtained from `http://dev.mysql.com/downloads/cluster/'. Source code for the latest MySQL Cluster NDB 7.1 release can be obtained from the same location. You can also access the MySQL Cluster NDB 7.1 development source tree at `https://code.launchpad.net/~mysql/mysql-server/mysql-cluster-7.1'. This release also incorporates all bugfixes and changes made in previous MySQL Cluster releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.47 (see *Note news-5-1-47::). *Functionality added or changed:* * Restrictions on some types of mismatches in column definitions when restoring data using *Note `ndb_restore': mysql-cluster-programs-ndb-restore. have been relaxed. These include the following types of mismatches: * Different `COLUMN_FORMAT' settings (`FIXED', `DYNAMIC', `DEFAULT') * Different `STORAGE' settings (`MEMORY', `DISK') * Different default values * Different distribution key settings Now, when one of these types of mismatches in column definitions is encountered, *Note `ndb_restore': mysql-cluster-programs-ndb-restore. no longer stops with an error; instead, it accepts the data and inserts it into the target table, while issuing a warning to the user. For more information, see *Note mysql-cluster-programs-ndb-restore::. (Bug #54423) See also Bug #53810, Bug #54178, Bug #54242, Bug #54279. * It is now possible to install management node and data node processes as Windows services. (See *Note mysql-cluster-install-windows-service::, for more information.) In addition, data node processes on Windows are now maintained by angel processes, just as they are on other platforms supported by MySQL Cluster. *Bugs fixed:* * The disconnection of all API nodes (including SQL nodes) during an *Note `ALTER TABLE': alter-table. caused a memory leak. (Bug #54685) * If a node shutdown (either in isolation or as part of a system shutdown) occurred directly following a local checkpoint, it was possible that this local checkpoint would not be used when restoring the cluster. (Bug #54611) * The setting for `BuildIndexThreads' was ignored by *Note `ndbmtd': mysql-cluster-programs-ndbmtd, which made it impossible to use more than 4 cores for rebuilding indexes. (Bug #54521) * When adding multiple new node groups to a MySQL Cluster, it was necessary for each new node group to add only the nodes to be assigned to the new node group, create that node group using `CREATE NODEGROUP', then repeat this process for each new node group to be added to the cluster. The fix for this issue makes it possible to add all of the new nodes at one time, and then issue several `CREATE NODEGROUP' commands in succession. (Bug #54497) * When performing an online alter table where 2 or more SQL nodes connected to the cluster were generating binary logs, an incorrect message could be sent from the data nodes, causing *Note `mysqld': mysqld. processes to crash. This problem was often difficult to detect, because restarting SQL node or data node processes could clear the error, and because the crash in *Note `mysqld': mysqld. did not occur until several minutes after the erroneous message was sent and received. (Bug #54168) * A table having the maximum number of attributes permitted could not be backed up using the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client. *Note*: The maximum number of attributes supported per table is not the same for all MySQL Cluster releases. See *Note mysql-cluster-limitations-database-objects::, to determine the maximum that applies in the release which you are using. (Bug #54155) * The presence of duplicate `[tcp]' sections in the `config.ini' file caused the management server to crash. Now in such cases, *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. fails gracefully with an appropriate error message. (Bug #49400) * The two MySQL Server options, `--ndb-wait-connected' and `--ndb-wait-setup', did not set the corresponding system variables. (Bug #48402) * *Cluster Replication*: An error in an `NDB' internal byte mask value could lead to corruption of replicated *Note `BIT': numeric-types. column values. (Bug #54005) See also Bug #53622. * *Cluster API*: When using the NDB API, it was possible to rename a table with the same name as that of an existing table. *Note*: This issue did not affect table renames executed using SQL on MySQL servers acting as MySQL Cluster API nodes. (Bug #54651) * *Cluster API*: An excessive number of client connections, such that more than 1024 file descriptors, sockets, or both were open, caused NDB API applications to crash. (Bug #34303)  File: manual.info, Node: mysql-cluster-news-5-1-44-ndb-7-1-4b, Next: mysql-cluster-news-5-1-44-ndb-7-1-4a, Prev: mysql-cluster-news-5-1-47-ndb-7-1-5, Up: mysql-cluster-news-7-1 17.7.2.14 Changes in MySQL Cluster NDB 7.1.4b (5.1.44-ndb-7.1.4b) (18 June 2010) ................................................................................ This release replaces MySQL Cluster NDB 7.1.4, fixing a critical issue in that version that was discovered shortly after its release (Bug#54242), as well as MySQL Cluster NDB 7.1.4a, which was not actually released due to Bug#54516 being found during testing. Users of MySQL Cluster NDB 7.1.3 or MySQL Cluster NDB 7.1.4 should upgrade to the 7.1.4b release as soon as possible. Obtaining MySQL Cluster NDB 7.1.4b The latest MySQL Cluster NDB 7.1 binaries for supported platforms can be obtained from `http://dev.mysql.com/downloads/cluster/'. Source code for the latest MySQL Cluster NDB 7.1 release can be obtained from the same location. You can also access the MySQL Cluster NDB 7.1 development source tree at `https://code.launchpad.net/~mysql/mysql-server/mysql-cluster-7.1'. This release also incorporates all bugfixes and changes made in previous MySQL Cluster releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.44 (see *Note news-5-1-44::). *Functionality added or changed:* * *Important Change*: Commercial binary releases of MySQL Cluster NDB 7.1 now include support for the `InnoDB' storage engine. (Bug #52945) The patch for the following bugs was reverted: Bug #31989. *Bugs fixed:* * *Cluster API*: The value of an internal constant used in the implementation of the `NdbOperation' and `NdbScanOperation' classes caused MySQL Cluster NDB 7.0 NDB API applications compiled against MySQL Cluster NDB 7.0.14 or earlier to fail when run with MySQL Cluster 7.0.15, and MySQL Cluster NDB 7.1 NDB API applications compiled against MySQL Cluster NDB 7.1.3 or earlier to break when used with MySQL Cluster 7.1.4. (Bug #54516)  File: manual.info, Node: mysql-cluster-news-5-1-44-ndb-7-1-4a, Next: mysql-cluster-news-5-1-44-ndb-7-1-4, Prev: mysql-cluster-news-5-1-44-ndb-7-1-4b, Up: mysql-cluster-news-7-1 17.7.2.15 Changes in MySQL Cluster NDB 7.1.4a (5.1.44-ndb-7.1.4a) (Not released) ................................................................................ This was intended as a replacement release for MySQL Cluster NDB 7.1.4, fixing a critical issue in that version that was discovered shortly after its release (Bug#54242); however, MySQL Cluster NDB 7.1.4a was not actually released due to Bug#54516 being found during testing. Users of MySQL Cluster NDB 7.1.3 or MySQL Cluster NDB 7.1.4 should upgrade to the 7.1.4b release as soon as possible. Obtaining MySQL Cluster NDB 7.1 The latest MySQL Cluster NDB 7.1 binaries for supported platforms can be obtained from `http://dev.mysql.com/downloads/cluster/'. Source code for the latest MySQL Cluster NDB 7.1 release can be obtained from the same location. You can also access the MySQL Cluster NDB 7.1 development source tree at `https://code.launchpad.net/~mysql/mysql-server/mysql-cluster-7.1'. This release also incorporates all bugfixes and changes made in previous MySQL Cluster releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.44 (see *Note news-5-1-44::). *Bugs fixed:* * When using *Note `mysqldump': mysqldump. to back up and restore schema information while using *Note `ndb_restore': mysql-cluster-programs-ndb-restore. for restoring only the data, restoring to MySQL Cluster NDB 7.1.4 from an older version failed on tables having columns with default values. This was because versions of MySQL Cluster prior to MySQL Cluster NDB 7.1.4 did not have native support for default values. In addition, the MySQL Server supports *Note `TIMESTAMP': datetime. columns having dynamic default values, such as `DEFAULT CURRENT_TIMESTAMP'; however, the current implementation of `NDB'-native default values permits only a constant default value. To fix this issue, the manner in which `NDB' treats *Note `TIMESTAMP': datetime. columns is reverted to its pre-NDB-7.1.4 behavior (obtaining the default value from *Note `mysqld': mysqld. rather than `NDBCLUSTER') except where a *Note `TIMESTAMP': datetime. column uses a constant default, as in the case of a column declared as `TIMESTAMP DEFAULT 0' or `TIMESTAMP DEFAULT 20100607174832'. (Bug #54242)  File: manual.info, Node: mysql-cluster-news-5-1-44-ndb-7-1-4, Next: mysql-cluster-news-5-1-44-ndb-7-1-3, Prev: mysql-cluster-news-5-1-44-ndb-7-1-4a, Up: mysql-cluster-news-7-1 17.7.2.16 Changes in MySQL Cluster NDB 7.1.4 (5.1.44-ndb-7.1.4) (31 May 2010) ............................................................................. MySQL Cluster NDB 7.1.4 is a new release of MySQL Cluster, incorporating new features in the *Note `NDBCLUSTER': mysql-cluster. storage engine and fixing recently discovered bugs in MySQL Cluster NDB 7.1.3 and previous MySQL Cluster releases. Obtaining MySQL Cluster NDB 7.1 The latest MySQL Cluster NDB 7.1 binaries for supported platforms can be obtained from `http://dev.mysql.com/downloads/cluster/'. Source code for the latest MySQL Cluster NDB 7.1 release can be obtained from the same location. You can also access the MySQL Cluster NDB 7.1 development source tree at `https://code.launchpad.net/~mysql/mysql-server/mysql-cluster-7.1'. This release also incorporates all bugfixes and changes made in previous MySQL Cluster releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.44 (see *Note news-5-1-44::). *Functionality added or changed:* * *Important Change*: The maximum number of attributes (columns plus indexes) per table has increased to 512. * A `--wait-nodes' option has been added for *Note `ndb_waiter': mysql-cluster-programs-ndb-waiter. When this option is used, the program waits only for the nodes having the listed IDs to reach the desired state. For more information, see *Note mysql-cluster-programs-ndb-waiter::. (Bug #52323) * As part of this change, new methods relating to default values have been added to the `Column' and `Table' classes in the NDB API. For more information, see `Column::getDefaultValue()' (http://dev.mysql.com/doc/ndbapi/en/ndb-column-methods.html#ndb-column-getdefaultvalue), `Column::setDefaultValue()' (http://dev.mysql.com/doc/ndbapi/en/ndb-column-methods.html#ndb-column-setdefaultvalue), and `Table::hasDefaultValues()' (http://dev.mysql.com/doc/ndbapi/en/ndb-table-methods.html#ndb-table-hasdefaultvalues). (Bug #30529) * Added the MySQL Cluster management server option `--config-cache', which makes it possible to enable and disable configuration caching. This option is turned on by default; to disable configuration caching, start *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. with `--config-cache=0', or with `--skip-config-cache'. See *Note mysql-cluster-programs-ndb-mgmd::, for more information. * Added the `--skip-unknown-objects' option for *Note `ndb_restore': mysql-cluster-programs-ndb-restore. This option causes *Note `ndb_restore': mysql-cluster-programs-ndb-restore. to ignore any schema objects which it does not recognize. Currently, this is useful chiefly for restoring native backups made from a cluster running MySQL Cluster NDB 7.0 to a cluster running MySQL Cluster NDB 6.3. *Bugs fixed:* * *Cluster API*: *Incompatible Change*: The default behavior of the NDB API Event API has changed as follows: Previously, when creating an `Event', DDL operations (alter and drop operations on tables) were automatically reported on any event operation that used this event, but as a result of this change, this is no longer the case. Instead, you must now invoke the event's `setReport()' method, with the new `EventReport' value `ER_DDL', to get this behavior. For existing NDB API applications where you wish to retain the old behavior, you must update the code as indicated previously, then recompile, following an upgrade. Otherwise, DDL operations are no longer reported after upgrading `libndbnclient'. For more information, see The `Event::EventReport' Type (http://dev.mysql.com/doc/ndbapi/en/ndb-event-types.html#ndb-event-eventreport), and `Event::setReport()' (http://dev.mysql.com/doc/ndbapi/en/ndb-event-methods.html#ndb-event-setreport). (Bug #53308) * After creating *Note `NDB': mysql-cluster. tables until creation of a table failed due to *Note `NDB': mysql-cluster. error 905 `Out of attribute records (increase MaxNoOfAttributes)', then increasing `MaxNoOfAttributes' and restarting all management node and data node processes, attempting to drop and re-create one of the tables failed with the error `Out of table records...', even when sufficient table records were available. (Bug #53944) See also Bug #52055. * Creating a Disk Data table, dropping it, then creating an in-memory table and performing a restart, could cause data node processes to fail with errors in the `DBTUP' kernel block if the new table's internal ID was the same as that of the old Disk Data table. This could occur because undo log handling during the restart did not check that the table having this ID was now in-memory only. (Bug #53935) * A table created while `ndb_table_no_logging' was enabled was not always stored to disk, which could lead to a data node crash with `Error opening DIH schema files for table'. (Bug #53934) * An internal buffer allocator used by *Note `NDB': mysql-cluster. has the form `alloc(WANTED, MINIMUM)' and attempts to allocate WANTED pages, but is permitted to allocate a smaller number of pages, between WANTED and MINIMUM. However, this allocator could sometimes allocate fewer than MINIMUM pages, causing problems with multi-threaded building of ordered indexes. (Bug #53580) * When compiled with support for `epoll' but this functionality is not available at runtime, MySQL Cluster tries to fall back to use the `select()' function in its place. However, an extra `ndbout_c()' call in the transporter registry code caused *Note `ndbd': mysql-cluster-programs-ndbd. to fail instead. (Bug #53482) * The value set for the *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. option `--ndb-nodeid' was not verified prior to use as being within the permitted range (1 to 255, inclusive), leading to a crash of the management server. (Bug #53412) * `NDB' truncated a column declared as *Note `DECIMAL(65,0)': numeric-types. to a length of 64. Now such a column is accepted and handled correctly. In cases where the maximum length (65) is exceeded, `NDB' now raises an error instead of truncating. (Bug #53352) * When an `NDB' log handler failed, the memory allocated to it was freed twice. (Bug #53200) * Setting `DataMemory' higher than 4G on 32-bit platforms caused *Note `ndbd': mysql-cluster-programs-ndbd. to crash, instead of failing gracefully with an error. (Bug #52536, Bug #50928) * When the `LogDestination' parameter was set using with a relative path, the management server failed to store its value unless started with `--initial' or `--reload'. (Bug #52268) * When creating an index, *Note `NDB': mysql-cluster. failed to check whether the internal ID allocated to the index was within the permissible range, leading to an assertion. This issue could manifest itself as a data node failure with `NDB' error 707 (`No more table metadata records (increase MaxNoOfTables)'), when creating tables in rapid succession (for example, by a script, or when importing from *Note `mysqldump': mysqldump.), even with a relatively high value for `MaxNoOfTables' and a relatively low number of tables. (Bug #52055) * *Note `ndb_restore': mysql-cluster-programs-ndb-restore. did not raise any errors if hashmap creation failed during execution. (Bug #51434) * Specifying the node ID as part of the `--ndb-connectstring' option to *Note `mysqld': mysqld. was not handled correctly. The fix for this issue includes the following changes: * Multiple occurrences of any of the *Note `mysqld': mysqld. options `--ndb-connectstring', `--ndb-mgmd-host', and `--ndb-nodeid' are now handled in the same way as with other MySQL server options, in that the value set in the last occurrence of the option is the value that is used by *Note `mysqld': mysqld. Now, if `--ndb-nodeid' is used, its value overrides that of any `nodeid' setting used in `--ndb-connectstring'. For example, starting *Note `mysqld': mysqld. with `--ndb-connectstring=nodeid=1,10.100.1.100 --ndb-nodeid=3' now produces the same result as starting it with `--ndb-connectstring=nodeid=3,10.100.1.100'. * The 1024-character limit on the length of the connectstring is removed, and `--ndb-connectstring' is now handled in this regard in the same way as other *Note `mysqld': mysqld. options. * In the NDB API, a new constructor for `Ndb_cluster_connection' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndb-cluster-connection.html#ndb-ndb-cluster-connection) is added which takes as its arguments a connectstring and the node ID to force the API node to use. (Bug #44299) * NDB did not distinguish correctly between table names differing only by lettercase when `lower_case_table_names' was set to 0. (Bug #33158) * `ndb_mgm -e "ALL STATUS"' erroneously reported that data nodes remained in start phase 0 until they had actually started. * *Replication*: A buffer overrun in the handling of *Note `DATE': datetime. column values could cause mysqlbinlog to fail when reading back logs containing certain combinations of DML on a table having a *Note `DATE': datetime. column followed by dropping the table. (Bug #52202) * *Cluster Replication*: Replication failed after a restart of the slave SQL node, due to an error in writing the `master.info' file. (Bug #52859) * *Note `ALTER TABLE': alter-table. did not work correctly where the name of the table, the database, or both contained special characters, causing the MySQL server to crash. (Bug #52225) See also Bug #53409, Bug #14959. * The performance of MySQL applications using non-persistent client connections was adversely affected due to many of these connections being kept waiting for an excessive length of time in cleanup phase while being closed. (Bug #48832) * The MySQL client library mishandled `EINPROGRESS' errors for connections in nonblocking mode. This could lead to replication failures on hosts capable of resolving both IPv4 and IPv6 network addresses, when trying to resolve `localhost'. (Bug #37267) See also Bug #44344.  File: manual.info, Node: mysql-cluster-news-5-1-44-ndb-7-1-3, Next: mysql-cluster-news-5-1-41-ndb-7-1-2, Prev: mysql-cluster-news-5-1-44-ndb-7-1-4, Up: mysql-cluster-news-7-1 17.7.2.17 Changes in MySQL Cluster NDB 7.1.3 (5.1.44-ndb-7.1.3) (12 April 2010 General Availability) .................................................................................................... MySQL Cluster NDB 7.1.3 is the first _General Availability_ release in the MySQL Cluster NDB 7.1 release series, incorporating new features in the *Note `NDBCLUSTER': mysql-cluster. storage engine and fixing recently discovered bugs in MySQL Cluster NDB 7.1.2-beta and previous MySQL Cluster releases. Obtaining MySQL Cluster NDB 7.1 The latest MySQL Cluster NDB 7.1 binaries for supported platforms can be obtained from `http://dev.mysql.com/downloads/cluster/'. Source code for the latest MySQL Cluster NDB 7.1 release can be obtained from the same location. You can also access the MySQL Cluster NDB 7.1 development source tree at `https://code.launchpad.net/~mysql/mysql-server/mysql-cluster-7.1'. This release also incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.x, MySQL Cluster NDB 7.0, and MySQL Cluster NDB 7.1 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.44 (see *Note news-5-1-44::). *Functionality added or changed:* * *Incompatible Change*: The schema for the *Note `memoryusage': mysql-cluster-ndbinfo-memoryusage. table of the *Note `ndbinfo': mysql-cluster-ndbinfo. information database has changed, as detailed in the following list: * The `max' column has been renamed to `total'. * The `used' and `total' (formerly `max') columns now display values in bytes rather than memory pages. * Added the columns `used_pages' and `total_pages' to show the amount of a resource used and total amount available in pages. * The size of the memory pages used for calculating data memory (`used_pages' and `total_pages' columns) is now 32K rather than 16K. For more information, aee *Note mysql-cluster-ndbinfo-memoryusage::. * *Important Change*: The experimental *Note `pools': mysql-cluster-ndbinfo-pools. table has been removed from the *Note `ndbinfo': mysql-cluster-ndbinfo. database. Information useful to MySQL Cluster administration that was contained in this table should be available from other *Note `ndbinfo': mysql-cluster-ndbinfo. tables. * *Important Note*: MySQL Cluster 7.1 is now supported for production use on Windows platforms. *Important*: Some limitations specific to Windows remain; the most important of these are given in the following list: * There is not yet any Windows installer for MySQL Cluster; you must extract, place, configure, and start the necessary MySQL Cluster executables manually. * MySQL Cluster processes cannot yet be installed as Windows services. This means that each process executable must be run from a command prompt, and cannot be backgrounded. If you close the command prompt window in which you started the process, the process terminates. * There is as yet no `angel' process for data nodes; if a data node process quits, it must be restarted manually. * *Note `ndb_error_reporter': mysql-cluster-programs-ndb-error-reporter. is not yet available on Windows. * The multi-threaded data node process (*Note `ndbmtd': mysql-cluster-programs-ndbmtd.) is not yet included in the binary distribution. However, it should be built automatically if you build MySQL Cluster from source. As with MySQL Cluster on other supported platforms, you cannot build MySQL Cluster for Windows from the MySQL Server 5.1 sources; you must use the source code from the MySQL Cluster NDB 7.1 tree. * *Cluster Replication*: *Replication*: MySQL Cluster Replication now supports attribute promotion and demotion for row-based replication between columns of different but similar types on the master and the slave. For example, it is possible to promote an *Note `INT': numeric-types. column on the master to a *Note `BIGINT': numeric-types. column on the slave, and to demote a *Note `TEXT': blob. column to a *Note `VARCHAR': char. column. The implementation of type demotion distinguishes between lossy and non-lossy type conversions, and their use on the slave can be controlled by setting the `slave_type_conversions' global server system variable. For more information about attribute promotion and demotion for row-based replication in MySQL Cluster, see *Note replication-features-attribute-promotion::. (Bug #47163, Bug #46584) *Bugs fixed:* * If a node or cluster failure occurred while *Note `mysqld': mysqld. was scanning the `ndb.ndb_schema' table (which it does when attempting to connect to the cluster), insufficient error handling could lead to a crash by *Note `mysqld': mysqld. in certain cases. This could happen in a MySQL Cluster with a great many tables, when trying to restart data nodes while one or more *Note `mysqld': mysqld. processes were restarting. (Bug #52325) * In MySQL Cluster NDB 7.0 and later, DDL operations are performed within schema transactions; the NDB kernel code for starting a schema transaction checks that all data nodes are at the same version before permitting a schema transaction to start. However, when a version mismatch was detected, the client was not actually informed of this problem, which caused the client to hang. (Bug #52228) * After running a mixed series of node and system restarts, a system restart could hang or fail altogether. This was caused by setting the value of the newest completed global checkpoint too low for a data node performing a node restart, which led to the node reporting incorrect GCI intervals for its first local checkpoint. (Bug #52217) * When performing a complex mix of node restarts and system restarts, the node that was elected as master sometimes required optimized node recovery due to missing `REDO' information. When this happened, the node crashed with `Failure to recreate object ... during restart, error 721' (because the `DBDICT' restart code was run twice). Now when this occurs, node takeover is executed immediately, rather than being made to wait until the remaining data nodes have started. (Bug #52135) See also Bug #48436. * The internal variable `ndb_new_handler', which is no longer used, has been removed. (Bug #51858) * `ha_ndbcluster.cc' was not compiled with the same `SAFEMALLOC' and `SAFE_MUTEX' flags as the MySQL Server. (Bug #51857) * When debug compiling MySQL Cluster on Windows, the mysys library was not compiled with -DSAFEMALLOC and -DSAFE_MUTEX, due to the fact that my_socket.c was misnamed as my_socket.cc. (Bug #51856) * Some values shown in the *Note `memoryusage': mysql-cluster-ndbinfo-memoryusage. table did not match corresponding values shown by the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client `ALL REPORT MEMORYUSAGE' command. (Bug #51735) * The redo log protects itself from being filled up by periodically checking how much space remains free. If insufficient redo log space is available, it sets the state `TAIL_PROBLEM' which results in transactions being aborted with error code 410 (`out of redo log'). However, this state was not set following a node restart, which meant that if a data node had insufficient redo log space following a node restart, it could crash a short time later with `Fatal error due to end of REDO log'. Now, this space is checked during node restarts. (Bug #51723) * Restoring a MySQL Cluster backup between platforms having different endianness failed when also restoring metadata and the backup contained a hashmap not already present in the database being restored to. This issue was discovered when trying to restore a backup made on Solaris/SPARC to a MySQL Cluster running on Solaris/x86, but could conceivably occur in other cases where the endianness of the platform on which the backup was taken differed from that of the platform being restored to. (Bug #51432) * A *Note `mysqld': mysqld, when attempting to access the *Note `ndbinfo': mysql-cluster-ndbinfo. database, crashed if could not contact the management server. (Bug #51067) * The *Note `mysql': mysql. client `system' command did not work properly. This issue was only known to affect the version of the *Note `mysql': mysql. client that was included with MySQL Cluster NDB 7.0 and MySQL Cluster NDB 7.1 releases. (Bug #48574) * *Cluster API*: *Packaging*: The file `META-INF/services/org.apache.openjpa.lib.conf.ProductDerivation' was missing from the `clusterjpa' JAR file. This could cause setting `openjpa.BrokerFactory' to ``ndb'' to be rejected. (Bug #52106) * *Disk Data*: Inserts of blob column values into a MySQL Cluster Disk Data table that exhausted the tablespace resulted in misleading `no such tuple' error messages rather than the expected error `tablespace full'. This issue appeared similar to Bug#48113, but had a different underlying cause. (Bug #52201) * *Disk Data*: DDL operations on Disk Data tables having a relatively small `UNDO_BUFFER_SIZE' could fail unexpectedly. * *Cluster Replication*: The `--ndb-log-empty-epochs' option did not work correctly. (Bug #49559) * *Cluster Replication*: When *Note `mysqld': mysqld. was started with `--binlog-do-db' or `--binlog-ignore-db', no `LOST_EVENTS' incident was written to the binary log. (Bug #47096) * *Cluster API*: A number of issues were corrected in the NDB API coding examples found in the `storage/ndb/ndbapi-examples' directory in the MySQL Cluster source tree. These included possible endless recursion in `ndbapi_scan.cpp' as well as problems running some of the examples on systems using Windows or Mac OS X due to the lettercase used for some table names. (Bug #30552, Bug #30737)  File: manual.info, Node: mysql-cluster-news-5-1-41-ndb-7-1-2, Next: mysql-cluster-news-5-1-41-ndb-7-1-1, Prev: mysql-cluster-news-5-1-44-ndb-7-1-3, Up: mysql-cluster-news-7-1 17.7.2.18 Changes in MySQL Cluster NDB 7.1.2 (5.1.41-ndb-7.1.2) (02 March 2010) ............................................................................... MySQL Cluster NDB 7.1.2 is a new beta release of MySQL Cluster, incorporating new features in the *Note `NDBCLUSTER': mysql-cluster. storage engine and fixing recently discovered bugs in MySQL Cluster NDB 7.1.1 and previous MySQL Cluster releases. Obtaining MySQL Cluster NDB 7.1 The latest MySQL Cluster NDB 7.1 binaries for supported platforms can be obtained from `http://dev.mysql.com/downloads/cluster/'. Source code for the latest MySQL Cluster NDB 7.1 release can be obtained from the same location. You can also access the MySQL Cluster NDB 7.1 development source tree at `https://code.launchpad.net/~mysql/mysql-server/mysql-cluster-7.1'. This release also incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.1, 6.2, 6.3, and 7.0 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.41 (see *Note news-5-1-41::). *Functionality added or changed:* * *Cluster API*: It is now possible to determine, using the *Note `ndb_desc': mysql-cluster-programs-ndb-desc. utility or the NDB API, which data nodes contain replicas of which partitions. For *Note `ndb_desc': mysql-cluster-programs-ndb-desc, a new `--extra-node-info' option is added to cause this information to be included in its output. A new method `Table::getFragmentNodes()' is added to the NDB API for obtaining this information programmatically. (Bug #51184) * Numeric codes used in management server status update messages in the cluster logs have been replaced with text descriptions. (Bug #49627) See also Bug #44248. * A new configuration parameter `HeartbeatThreadPriority' makes it possible to select between a first-in, first-out or round-round scheduling policy for management node and API node heartbeat threads, as well as to set the priority of these threads. See *Note mysql-cluster-mgm-definition::, or *Note mysql-cluster-api-definition::, for more information. (Bug #49617) * Start phases are now written to the data node logs. (Bug #49158) * Formerly, the `REPORT' and `DUMP' commands returned output to all *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. clients connected to the same MySQL Cluster. Now, these commands return their output only to the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client that actually issued the command. (Bug #40865) * *Disk Data*: The *Note `ndb_desc': mysql-cluster-programs-ndb-desc. utility can now show the extent space and free extent space for subordinate *Note `BLOB': blob. and *Note `TEXT': blob. columns (stored in hidden `BLOB' tables by NDB). A `--blob-info' option has been added for this program that causes *Note `ndb_desc': mysql-cluster-programs-ndb-desc. to generate a report for each subordinate `BLOB' table. For more information, see *Note mysql-cluster-programs-ndb-desc::. (Bug #50599) *Bugs fixed:* * *Important Change*: The `DATA_MEMORY' column of the *Note `memoryusage': mysql-cluster-ndbinfo-memoryusage. table was renamed to `memory_type'. (Bug #50926) * When deciding how to divide the REDO log, the `DBDIH' kernel block saved more than was needed to restore the previous local checkpoint, which could cause REDO log space to be exhausted prematurely (`NDB' error 410). (Bug #51547) * DML operations can fail with `NDB' error 1220 (`REDO log files overloaded...') if the opening and closing of REDO log files takes too much time. If this occurred as a GCI marker was being written in the REDO log while REDO log file 0 was being opened or closed, the error could persist until a GCP stop was encountered. This issue could be triggered when there was insufficient REDO log space (for example, with configuration parameter settings `NoOfFragmentLogFiles = 6' and `FragmentLogFileSize = 6M') with a load including a very high number of updates. (Bug #51512) See also Bug #20904. * An attempted online upgrade from a MySQL Cluster NDB 6.3 or 7.0 release to a MySQL Cluster NDB 7.1 release failed, as the first upgraded data node rejected the remaining data nodes as using incompatible versions. (Bug #51429) * A side effect of the *Note `ndb_restore': mysql-cluster-programs-ndb-restore. `--disable-indexes' and `--rebuild-indexes' options is to change the schema versions of indexes. When a *Note `mysqld': mysqld. later tried to drop a table that had been restored from backup using one or both of these options, the server failed to detect these changed indexes. This caused the table to be dropped, but the indexes to be left behind, leading to problems with subsequent backup and restore operations. (Bug #51374) * The output of the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client `REPORT BACKUPSTATUS' command could sometimes contain errors due to uninitialized data. (Bug #51316) * Setting `IndexMemory' greater than 2GB could cause data nodes to crash while starting. (Bug #51256) * *Note `ndb_restore': mysql-cluster-programs-ndb-restore. crashed while trying to restore a corrupted backup, due to missing error handling. (Bug #51223) * The *Note `ndb_restore': mysql-cluster-programs-ndb-restore. message `Successfully created index `PRIMARY`...' was directed to `stderr' instead of `stdout'. (Bug #51037) * An initial restart of a data node configured with a large amount of memory could fail with a `Pointer too large' error. (Bug #51027) This regression was introduced by Bug #47818. * When using `NoOfReplicas' equal to 1 or 2, if data nodes from one node group were restarted 256 times and applications were running traffic such that it would encounter *Note `NDB': mysql-cluster. error 1204 (`Temporary failure, distribution changed'), the live node in the node group would crash, causing the cluster to crash as well. The crash occurred only when the error was encountered on the 256th restart; having the error on any previous or subsequent restart did not cause any problems. (Bug #50930) * A `GROUP BY' query against *Note `NDB': mysql-cluster. tables sometimes did not use any indexes unless the query included a `FORCE INDEX' option. With this fix, indexes are used by such queries (where otherwise possible) even when `FORCE INDEX' is not specified. (Bug #50736) * *Note `ndbmtd': mysql-cluster-programs-ndbmtd. started on a single-core machine could sometimes fail with a `Job Buffer Full' error when `MaxNoOfExecutionThreads' was set greater than `LockExecuteThreadToCPU'. Now a warning is logged when this occurs. (Bug #50582) * The following issues were fixed in the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client `REPORT MEMORYUSAGE' command: * The client sometimes inserted extra `ndb_mgm>' prompts within the output. * For data nodes running *Note `ndbmtd': mysql-cluster-programs-ndbmtd, `IndexMemory' was reported before `DataMemory'. * In addition, for data nodes running *Note `ndbmtd': mysql-cluster-programs-ndbmtd, there were multiple `IndexMemory' entries listed in the output. (Bug #50196) * Issuing a command in the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client after it had lost its connection to the management server could cause the client to crash. (Bug #49219) * Replication of a MySQL Cluster using multi-threaded data nodes could fail with forced shutdown of some data nodes due to the fact that *Note `ndbmtd': mysql-cluster-programs-ndbmtd. exhausted `LongMessageBuffer' much more quickly than *Note `ndbd': mysql-cluster-programs-ndbd. After this fix, passing of replication data between the `DBTUP' and `SUMA' NDB kernel blocks is done using `DataMemory' rather than `LongMessageBuffer'. Until you can upgrade, you may be able to work around this issue by increasing the `LongMessageBuffer' setting; doubling the default should be sufficient in most cases. (Bug #46914) * Information about several management client commands was missing from (that is, truncated in) the output of the `HELP' command. (Bug #46114) * A *Note `SELECT': select. requiring a sort could fail with the error `Can't find record in 'TABLE'' when run concurrently with a *Note `DELETE': delete. from the same table. (Bug #45687) * When the `MemReportFrequency' configuration parameter was set in `config.ini', the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client `REPORT MEMORYUSAGE' command printed its output multiple times. (Bug #37632) * *Note `ndb_mgm -e "... REPORT ..."': mysql-cluster-programs-ndb-mgm. did not write any output to `stdout'. The fix for this issue also prevents the cluster log from being flooded with `INFO' messages when `DataMemory' usage reaches 100%, and insures that when the usage is decreased, an appropriate message is written to the cluster log. (Bug #31542, Bug #44183, Bug #49782) * *Disk Data*: The error message returned after atttempting to execute *Note `ALTER LOGFILE GROUP': alter-logfile-group. on an nonexistent logfile group did not indicate the reason for the failure. (Bug #51111) * *Cluster API*: An issue internal to *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. could cause problems when trying to start a large number of data nodes at the same time. (Bug #51273) See also Bug #51310. * *Cluster API*: When reading blob data with lock mode `LM_SimpleRead', the lock was not upgraded as expected. (Bug #51034)  File: manual.info, Node: mysql-cluster-news-5-1-41-ndb-7-1-1, Next: mysql-cluster-news-5-1-39-ndb-7-1-0, Prev: mysql-cluster-news-5-1-41-ndb-7-1-2, Up: mysql-cluster-news-7-1 17.7.2.19 Changes in MySQL Cluster NDB 7.1.1 (5.1.41-ndb-7.1.1) (01 February 2010 beta) ....................................................................................... MySQL Cluster NDB 7.1.1 is a new beta release of MySQL Cluster, incorporating new features in the *Note `NDBCLUSTER': mysql-cluster. storage engine and fixing recently discovered bugs in MySQL Cluster NDB 7.0 and previous MySQL Cluster releases. Obtaining MySQL Cluster NDB 7.1 The latest MySQL Cluster NDB 7.1 binaries for supported platforms can be obtained from `http://dev.mysql.com/downloads/cluster/'. Source code for the latest MySQL Cluster NDB 7.1 release can be obtained from the same location. You can also access the MySQL Cluster NDB 7.1 development source tree at `https://code.launchpad.net/~mysql/mysql-server/mysql-cluster-7.1'. https://code.launchpad.net/~mysql/mysql-server/mysql-5.1-telco-6.3 This release also incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.1, 6.2, 6.3, and 7.0 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.41 (see *Note news-5-1-41::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * The *Note `ndbinfo': mysql-cluster-ndbinfo. database is added to provide MySQL Cluster metadata in real time. The tables making up this database contain information about memory, buffer, and other resource usage, as well as configuration parameters and settings, event counts, and other useful data. Access to *Note `ndbinfo': mysql-cluster-ndbinfo. is done by executing standard SQL queries on its tables using the *Note `mysql': mysql. command-line client or other MySQL client application. No special setup procedures are required; *Note `ndbinfo': mysql-cluster-ndbinfo. is created automatically and visible in the output of *Note `SHOW DATABASES': show-databases. when the MySQL Server is connected to a MySQL Cluster. For more information, see *Note mysql-cluster-ndbinfo::. * *Cluster API*: ClusterJ 1.0 and ClusterJPA 1.0 are now available for programming Java applications with MySQL Cluster. ClusterJ is a Java connector providing an object-relational API for performing high-speed operations such as primary key lookups on a MySQL Cluster database, but does not require the use of the MySQL Server or JDBC (Connector/J). ClusterJ uses a new library NdbJTie which enables direct access from Java to the NDB API and thus to the *Note `NDBCLUSTER': mysql-cluster. storage engine. ClusterJPA is a new implementation of OpenJPA (http://openjpa.apache.org/), and can use either a JDBC connection to a MySQL Cluster SQL node (MySQL Server) or a direct connection to MySQL Cluster using NdbJTie, depending on availability and operational performance. ClusterJ, ClusterJPA, and NdbJTie require Java 1.5 or 1.6, and MySQL Cluster NDB 7.0 or later. All necessary libraries and other files for ClusterJ, ClusterJPA, and NdbJTie can be found in the MySQL Cluster NDB 7.1.1 or later distribution. *Bugs fixed:* * When a primary key lookup on an *Note `NDB': mysql-cluster. table containing one or more *Note `BLOB': blob. columns was executed in a transaction, a shared lock on any blob tables used by the *Note `NDB': mysql-cluster. table was held for the duration of the transaction. (This did not occur for indexed or non-indexed `WHERE' conditions.) Now in such cases, the lock is released after all *Note `BLOB': blob. data has been read. (Bug #49190)  File: manual.info, Node: mysql-cluster-news-5-1-39-ndb-7-1-0, Prev: mysql-cluster-news-5-1-41-ndb-7-1-1, Up: mysql-cluster-news-7-1 17.7.2.20 Changes in MySQL Cluster NDB 7.1.0 (5.1.39-ndb-7.1.0) (Not released alpha) .................................................................................... This version was for testing and internal use only, and not officially released. *Functionality added or changed:* * *Important Change*: The default value of the `DiskIOThreadPool' data node configuration parameter has changed from 8 to 2. * *Cluster Replication*: In circular replication, it was sometimes possible for an event to propagate such that it would be reapplied on all servers. This could occur when the originating server was removed from the replication circle and so could no longer act as the terminator of its own events, as normally happens in circular replication. To prevent this from occurring, a new `IGNORE_SERVER_IDS' option is introduced for the `CHANGE MASTER TO' statement. This option takes a list of replication server IDs; events having a server ID which appears in this list are ignored and not applied. For more information, see *Note change-master-to::. In conjunction with the introduction of `IGNORE_SERVER_IDS', *Note `SHOW SLAVE STATUS': show-slave-status. has two new fields. `Replicate_Ignore_Server_Ids' displays information about ignored servers. `Master_Server_Id' displays the `server_id' value from the master. (Bug #47037) See also Bug #25998, Bug #27808. *Bugs fixed:* * *Important Change*: The `--with-ndb-port-base' option for `configure' has been removed. It is now handled as an unknown and invalid option if you attempt to use it when configuring a build of MySQL Cluster. (Bug #47941) See also Bug #38502. * The value set by the `--ndb-cluster-connection-pool' option was not shown in the output of *Note `SHOW STATUS LIKE 'NDB%'': show-status. (Bug #44118) * When building storage engines on Windows it was not possible to specify additional libraries within the `CMake' file required for the build. An `${engine}_LIBS' macro has been included in the files to support these additional storage-engine specific libraries. (Bug #47797) * When building a pluggable storage engine on Windows, the engine name could be based on the directory name where the engine was located, rather than the configured storage engine name. (Bug #47795) * Installation of MySQL on Windows would fail to set the correct location for the character set files, which could lead to *Note `mysqld': mysqld. and *Note `mysql': mysql. failing to initialize properly. (Bug #17270)  File: manual.info, Node: mysql-cluster-news-7-0, Next: mysql-cluster-news-6-3, Prev: mysql-cluster-news-7-1, Up: mysql-cluster-news 17.7.3 Changes in MySQL Cluster NDB 7.0 --------------------------------------- * Menu: * mysql-cluster-news-5-1-56-ndb-7-0-27:: Changes in MySQL Cluster NDB 7.0.27 (5.1.56-ndb-7.0.27) (Not yet released) * mysql-cluster-news-5-1-56-ndb-7-0-26:: Changes in MySQL Cluster NDB 7.0.26 (5.1.56-ndb-7.0.26) (Not yet released) * mysql-cluster-news-5-1-56-ndb-7-0-25:: Changes in MySQL Cluster NDB 7.0.25 (5.1.56-ndb-7.0.25) (24 May 2011) * mysql-cluster-news-5-1-56-ndb-7-0-24:: Changes in MySQL Cluster NDB 7.0.24 (5.1.56-ndb-7.0.24) (26 April 2011) * mysql-cluster-news-5-1-51-ndb-7-0-23:: Changes in MySQL Cluster NDB 7.0.23 (5.1.51-ndb-7.0.23) (04 April 2011) * mysql-cluster-news-5-1-51-ndb-7-0-22:: Changes in MySQL Cluster NDB 7.0.22 (5.1.51-ndb-7.0.22) (25 February 2011) * mysql-cluster-news-5-1-51-ndb-7-0-21:: Changes in MySQL Cluster NDB 7.0.21 (5.1.51-ndb-7.0.21) (26 January 2011) * mysql-cluster-news-5-1-51-ndb-7-0-20a:: Changes in MySQL Cluster NDB 7.0.20a (5.1.51-ndb-7.0.20a) (18 November 2010) * mysql-cluster-news-5-1-51-ndb-7-0-20:: Changes in MySQL Cluster NDB 7.0.20 (5.1.51-ndb-7.0.20) (08 November 2010) * mysql-cluster-news-5-1-47-ndb-7-0-19:: Changes in MySQL Cluster NDB 7.0.19 (5.1.47-ndb-7.0.19) (08 October 2010) * mysql-cluster-news-5-1-47-ndb-7-0-18:: Changes in MySQL Cluster NDB 7.0.18 (5.1.47-ndb-7.0.18) (03 September 2010) * mysql-cluster-news-5-1-47-ndb-7-0-17:: Changes in MySQL Cluster NDB 7.0.17 (5.1.47-ndb-7.0.17) (16 August 2010) * mysql-cluster-news-5-1-47-ndb-7-0-16:: Changes in MySQL Cluster NDB 7.0.16 (5.1.47-ndb-7.0.16) (25 June 2010) * mysql-cluster-news-5-1-44-ndb-7-0-15b:: Changes in MySQL Cluster NDB 7.0.15b (5.1.44-ndb-7.0.15b) (18 June 2010) * mysql-cluster-news-5-1-44-ndb-7-0-15a:: Changes in MySQL Cluster NDB 7.0.15a (5.1.44-ndb-7.0.15a) (Not released) * mysql-cluster-news-5-1-44-ndb-7-0-15:: Changes in MySQL Cluster NDB 7.0.15 (5.1.44-ndb-7.0.15) (31 May 2010) * mysql-cluster-news-5-1-44-ndb-7-0-14:: Changes in MySQL Cluster NDB 7.0.14 (5.1.44-ndb-7.0.14) (31 March 2010) * mysql-cluster-news-5-1-41-ndb-7-0-13:: Changes in MySQL Cluster NDB 7.0.13 (5.1.41-ndb-7.0.13) (04 March 2010) * mysql-cluster-news-5-1-41-ndb-7-0-12b:: Changes in MySQL Cluster NDB 7.0.12b (5.1.41-ndb-7.0.12b) (18 February 2010) * mysql-cluster-news-5-1-41-ndb-7-0-12a:: Changes in MySQL Cluster NDB 7.0.12a (5.1.41-ndb-7.0.12a) (15 February 2010) * mysql-cluster-news-5-1-41-ndb-7-0-12:: Changes in MySQL Cluster NDB 7.0.12 (5.1.41-ndb-7.0.12) (03 February 2010) * mysql-cluster-news-5-1-41-ndb-7-0-11b:: Changes in MySQL Cluster NDB 7.0.11b (5.1.41-ndb-7.0.11b) (18 February 2010) * mysql-cluster-news-5-1-41-ndb-7-0-11a:: Changes in MySQL Cluster NDB 7.0.11a (5.1.41-ndb-7.0.11a) (15 February 2010) * mysql-cluster-news-5-1-41-ndb-7-0-11:: Changes in MySQL Cluster NDB 7.0.11 (5.1.41-ndb-7.0.11) (02 February 2010) * mysql-cluster-news-5-1-39-ndb-7-0-10:: Changes in MySQL Cluster NDB 7.0.10 (5.1.39-ndb-7.0.10) (15 December 2009) * mysql-cluster-news-5-1-39-ndb-7-0-9b:: Changes in MySQL Cluster NDB 7.0.9b (5.1.39-ndb-7.0.9b) (10 November 2009) * mysql-cluster-news-5-1-39-ndb-7-0-9a:: Changes in MySQL Cluster NDB 7.0.9a (5.1.39-ndb-7.0.9a) (05 November 2009) * mysql-cluster-news-5-1-39-ndb-7-0-9:: Changes in MySQL Cluster NDB 7.0.9 (5.1.39-ndb-7.0.9) (31 October 2009) * mysql-cluster-news-5-1-37-ndb-7-0-8a:: Changes in MySQL Cluster NDB 7.0.8a (5.1.37-ndb-7.0.8a) (07 October 2009) * mysql-cluster-news-5-1-37-ndb-7-0-8:: Changes in MySQL Cluster NDB 7.0.8 (5.1.37-ndb-7.0.8) (30 September 2009) * mysql-cluster-news-5-1-35-ndb-7-0-7:: Changes in MySQL Cluster NDB 7.0.7 (5.1.35-ndb-7.0.7) (26 August 2009) * mysql-cluster-news-5-1-34-ndb-7-0-6:: Changes in MySQL Cluster NDB 7.0.6 (5.1.34-ndb-7.0.6) (26 May 2009) * mysql-cluster-news-5-1-32-ndb-7-0-5:: Changes in MySQL Cluster NDB 7.0.5 (5.1.32-ndb-7.0.5) (20 April 2009 General Availability) * mysql-cluster-news-5-1-32-ndb-7-0-4:: Changes in MySQL Cluster NDB 7.0.4 (5.1.32-ndb-7.0.4) (18 March 2008) * mysql-cluster-news-5-1-32-ndb-6-4-3:: Changes in MySQL Cluster NDB 6.4.3 (5.1.32-ndb-6.4.3) (23 February 2009) * mysql-cluster-news-5-1-31-ndb-6-4-2:: Changes in MySQL Cluster NDB 6.4.2 (5.1.31-ndb-6.4.2) (28 January 2009) * mysql-cluster-news-5-1-31-ndb-6-4-1:: Changes in MySQL Cluster NDB 6.4.1 (5.1.31-ndb-6.4.1) (21 January 2009) * mysql-cluster-news-5-1-30-ndb-6-4-0:: Changes in MySQL Cluster NDB 6.4.0 (5.1.30-ndb-6.4.0) (22 December 2008 Beta) This section contains change history information for MySQL Cluster releases based on version 7.0 of the *Note `NDBCLUSTER': mysql-cluster. storage engine. *Important*: Previously, version 7.0 of *Note `NDBCLUSTER': mysql-cluster. was known as version 6.4, and early development versions of MySQL Cluster NDB 7.0 were known as `MySQL Cluster 6.4'. The first four releases in this series were identified using NDB 6.4.x version numbers (NDB 6.4.0 through NDB 6.4.3). MySQL Cluster NDB 7.0.4 is the fifth release in this series. All future MySQL Cluster NDB 7.0 releases will use NDB 7.0.x version numbers. Users running MySQL Cluster NDB 6.4.3 should upgrade to MySQL Cluster NDB 7.0.4 (or a later MySQL Cluster NDB 7.0 release). For an overview of new features added in MySQL Cluster NDB 7.0, see *Note mysql-cluster-development-5-1-ndb-7-0::. When upgrading to a MySQL Cluster NDB 7.0 release from earlier MySQL Cluster releases, you should be aware of the following issues: * To perform an online upgrade to MySQL Cluster NDB 7.0 from a MySQL Cluster NDB 6.3 release, you must upgrade to MySQL Cluster NDB 7.0.6 or later. See *Note mysql-cluster-upgrade-downgrade-compatibility-7.x::, for more information. * You cannot use a mix of MySQL Cluster NDB 7.0 and earlier binaries, except as part of an online upgrade (where this is supported). You should replace all existing MySQL Cluster executables with the MySQL Cluster NDB 7.0 versions. * NDB API applications built against previous MySQL Cluster versions (NDB 6.3 and earlier) must be recompiled against against the MySQL Cluster NDB 7.0 sources.  File: manual.info, Node: mysql-cluster-news-5-1-56-ndb-7-0-27, Next: mysql-cluster-news-5-1-56-ndb-7-0-26, Prev: mysql-cluster-news-7-0, Up: mysql-cluster-news-7-0 17.7.3.1 Changes in MySQL Cluster NDB 7.0.27 (5.1.56-ndb-7.0.27) (Not yet released) ................................................................................... This release incorporates new features in the *Note `NDBCLUSTER': mysql-cluster. storage engine and fixes recently discovered bugs in MySQL Cluster NDB 7.0.26. Obtaining MySQL Cluster NDB 7.0 The latest MySQL Cluster NDB 7.0 binaries for supported platforms can be obtained from `http://dev.mysql.com/downloads/cluster/'. Source code for the latest MySQL Cluster NDB 7.0 release can be obtained from the same location. You can also access the MySQL Cluster NDB 7.0 development source tree at `https://code.launchpad.net/~mysql/mysql-server/mysql-cluster-7.0'. This release also incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.1, 6.2, 6.3, and 7.0 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.56 (see *Note news-5-1-56::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Bugs fixed:* * The maximum effective value for the `OverloadLimit' configuration parameter was limited by the value of `SendBufferMemory'. Now the value set for `OverloadLimit' is used correctly, up to this parameter's stated maximum (4G). (Bug #12712109)  File: manual.info, Node: mysql-cluster-news-5-1-56-ndb-7-0-26, Next: mysql-cluster-news-5-1-56-ndb-7-0-25, Prev: mysql-cluster-news-5-1-56-ndb-7-0-27, Up: mysql-cluster-news-7-0 17.7.3.2 Changes in MySQL Cluster NDB 7.0.26 (5.1.56-ndb-7.0.26) (Not yet released) ................................................................................... This release incorporates new features in the *Note `NDBCLUSTER': mysql-cluster. storage engine and fixes recently discovered bugs in MySQL Cluster NDB 7.0.25. Obtaining MySQL Cluster NDB 7.0 The latest MySQL Cluster NDB 7.0 binaries for supported platforms can be obtained from `http://dev.mysql.com/downloads/cluster/'. Source code for the latest MySQL Cluster NDB 7.0 release can be obtained from the same location. You can also access the MySQL Cluster NDB 7.0 development source tree at `https://code.launchpad.net/~mysql/mysql-server/mysql-cluster-7.0'. This release also incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.1, 6.2, 6.3, and 7.0 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.56 (see *Note news-5-1-56::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * Added the `MaxDMLOperationsPerTransaction' data node configuration parameter, which can be used to limit the number of DML operations used by a transaction; if the transaction requires more than this many DML operations, the transaction is aborted. (Bug #12589613) *Bugs fixed:* * When global checkpoint indexes were written with no intervening end-of-file or megabyte border markers, this could sometimes lead to a situation in which the end of the redo log was mistakenly regarded as being between these GCIs, so that if the restart of a data node took place before the start of the next redo log was overwritten, the node encountered an `Error while reading the REDO log'. (Bug #12653993, Bug #61500) See also Bug #56961. * Restarting a *Note `mysqld': mysqld. during a rolling upgrade with data nodes running a mix of old and new versions of the MySQL Cluster software caused the *Note `mysqld': mysqld. to run in read-only mode. (Bug #12651364, Bug #61498) * Error reporting has been improved for cases in which API nodes are unable to connect due to apparent unavailability of node IDs. (Bug #12598398) * Error messages for `Failed to convert connection' transporter registration problems were inspecific. (Bug #12589691) * Under certain rare circumstances, a data node process could fail with Signal 11 during a restart. This was due to uninitialized variables in the `QMGR' kernel block. (Bug #12586190) * Multiple management servers were unable to detect one another until all nodes had fully started. As part of the fix for this issue, two new status values `RESUME' and `CONNECTED' can be reported for management nodes in the output of the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client `SHOW' command (see *Note mysql-cluster-mgm-client-commands::). Two corresponding status values `NDB_MGM_NODE_STATUS_RESUME' and `NDB_MGM_NODE_STATUS_CONNECTED' are also added to the list of possible values for an `ndb_mgm_node_status' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-node-status.html) data structure in the MGM API. (Bug #12352191, Bug #48301) * Handling of the `MaxNoOfTables' and `MaxNoOfAttributes' configuration parameters was not consistent in all parts of the *Note `NDB': mysql-cluster. kernel, and were only strictly enforced by the `DBDICT' and `SUMA' kernel blocks. This could lead to problems when tables could be created but not replicated. Now these parameters are treated by `SUMA' and `DBDICT' as suggested maximums rather than hard limits, as they are elsewhere in the *Note `NDB': mysql-cluster. kernel. (Bug #61684) * It was not possible to shut down a management node while one or more data nodes were stopped (for whatever reason). This issue was a regression introduced in MySQL Cluster NDB 7.0.24 and MySQL Cluster NDB 7.1.13. (Bug #61607) See also Bug #61147. * *Cluster API*: Applications that included the header file `ndb_logevent.h' could not be built using the Microsoft Visual Studio C compiler or the Oracle (Sun) Studio C compiler due to empty struct definitions. (Bug #12678971) * *Cluster API*: Within a transaction, after creating, executing, and closing a scan, calling `NdbTransaction::refresh()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndbtransaction-methods.html#ndb-ndbtransaction-refresh) after creating and executing but not closing a second scan caused the application to crash. (Bug #12646659)  File: manual.info, Node: mysql-cluster-news-5-1-56-ndb-7-0-25, Next: mysql-cluster-news-5-1-56-ndb-7-0-24, Prev: mysql-cluster-news-5-1-56-ndb-7-0-26, Up: mysql-cluster-news-7-0 17.7.3.3 Changes in MySQL Cluster NDB 7.0.25 (5.1.56-ndb-7.0.25) (24 May 2011) .............................................................................. This release incorporates new features in the *Note `NDBCLUSTER': mysql-cluster. storage engine and fixes recently discovered bugs in MySQL Cluster NDB 7.0.24. Obtaining MySQL Cluster NDB 7.0 The latest MySQL Cluster NDB 7.0 binaries for supported platforms can be obtained from `http://dev.mysql.com/downloads/cluster/'. Source code for the latest MySQL Cluster NDB 7.0 release can be obtained from the same location. You can also access the MySQL Cluster NDB 7.0 development source tree at `https://code.launchpad.net/~mysql/mysql-server/mysql-cluster-7.0'. This release also incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.1, 6.2, 6.3, and 7.0 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.56 (see *Note news-5-1-56::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Bugs fixed:* * The internal `Ndb_getinaddr()' function has been rewritten to use `getaddrinfo()' instead of `my_gethostbyname_r()' (which is removed in a later version of the MySQL Server). (Bug #12542120) * Two unused test files in `storage/ndb/test/sql' contained incorrect versions of the GNU Lesser General Public License. The files and the directory containing them have been removed. (Bug #11810156) See also Bug #11810224. * Error 1302 gave the wrong error message (`Out of backup record'). This has been corrected to `A backup is already running'. (Bug #11793592) * When using two management servers, issuing in an *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client connected to one management server a `STOP' command for stopping the other management server caused Error 2002 (`Stop failed ... Send to process or receive failed.: Permanent error: Application error'), even though the `STOP' command actually succeeded, and the second *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. was shut down. (Bug #61147) * In *Note `ndbmtd': mysql-cluster-programs-ndbmtd, a node connection event is detected by a `CMVMI' thread which sends a `CONNECT_REP' signal to the `QMGR' kernel block. In a few isolated circumstances, a signal might be transfered to `QMGR' directly by the *Note `NDB': mysql-cluster. transporter before the `CONNECT_REP' signal actually arrived. This resulted in reports in the error log with status `Temporary error, restart node', and the message `Internal program error'. (Bug #61025) * Renaming a table having *Note `BLOB': blob. or *Note `TEXT': blob. columns (or both) to another database caused the SQL node to crash, and the table to become inaccessible afterwards. (Bug #60484) * Under heavy loads with many concurrent inserts, temporary failures in transactions could occur (and were misreported as being due to *Note `NDB': mysql-cluster. Error 899 `Rowid already allocated'). As part of the fix for this issue, *Note `NDB': mysql-cluster. Error 899 has been reclassified as an internal error, rather than as a temporary transaction error. (Bug #56051, Bug #11763354) * *Disk Data*: Accounting for `MaxNoOfOpenFiles' was incorrect with regard to to data files in MySQL Cluster Disk Data tablespaces. This could lead to a crash when `MaxNoOfOpenFiles' was exceeded. (Bug #12581213) * *Cluster Replication*: Operations that updated unique keys of *Note `NDB': mysql-cluster. tables could cause duplicate key errors when trying to execute the binary log. (Previously, row events in the binary log were ordered according to the partitioning of the base table, which could differ in order within the epoch for that in which they were executed. To keep this from happening, unique keys are now updated in deferred mode, meaning that all table rows are updated before any unique indexes are checked. Thus, the order of the row updates is no longer important. You should be aware that deferring constraint checking in this way is currently supported only by *Note `NDB': mysql-cluster, and thus only for replication between NDB tables on both the master and the slave. You cannot replicate updates of unique keys successfully when replicating from *Note `NDB': mysql-cluster. to a different storage engine such as *Note `MyISAM': myisam-storage-engine. or *Note `InnoDB': innodb-storage-engine. (Bug #47952, Bug #11756082)  File: manual.info, Node: mysql-cluster-news-5-1-56-ndb-7-0-24, Next: mysql-cluster-news-5-1-51-ndb-7-0-23, Prev: mysql-cluster-news-5-1-56-ndb-7-0-25, Up: mysql-cluster-news-7-0 17.7.3.4 Changes in MySQL Cluster NDB 7.0.24 (5.1.56-ndb-7.0.24) (26 April 2011) ................................................................................ This release incorporates new features in the *Note `NDBCLUSTER': mysql-cluster. storage engine and fixes recently discovered bugs in MySQL Cluster NDB 7.0.23. Obtaining MySQL Cluster NDB 7.0 The latest MySQL Cluster NDB 7.0 binaries for supported platforms can be obtained from `http://dev.mysql.com/downloads/cluster/'. Source code for the latest MySQL Cluster NDB 7.0 release can be obtained from the same location. You can also access the MySQL Cluster NDB 7.0 development source tree at `https://code.launchpad.net/~mysql/mysql-server/mysql-cluster-7.0'. This release also incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.1, 6.2, 6.3, and 7.0 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.56 (see *Note news-5-1-56::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * It is now possible to add data nodes online to a running MySQL Cluster without performing a rolling restart of the cluster or starting data node processes with the `--nowait-nodes' option. This can be done by setting `Nodegroup = 65536' in the `config.ini' file for any data nodes that should be started at a later time, when first starting the cluster. (It was possible to set `NodeGroup' to this value previously, but the management server failed to start.) As part of this fix, a new data node configuration parameter `StartNoNodeGroupTimeout' has been added. When the management server sees that there are data nodes with no node group (that is, nodes for which `Nodegroup = 65536'), it waits `StartNoNodeGroupTimeout' milliseconds before treating these nodes as though they were listed with the `--nowait-nodes' option, and proceeds to start. For more information, see *Note mysql-cluster-online-add-node::. (Bug #11766167, Bug #59213) * A `config_generation' column has been added to the *Note `nodes': mysql-cluster-ndbinfo-nodes. table of the *Note `ndbinfo': mysql-cluster-ndbinfo. database. By checking this column, it is now possible to determine which version or versions of the MySQL Cluster configuration file are in effect on the data nodes. This information can be especially useful when performing a rolling restart of the cluster in order to update its configuration. *Bugs fixed:* * *Cluster API*: A unique index operation is executed in two steps: a lookup on an index table, and an operation on the base table. When the operation on the base table failed, while being executed in a batch with other operations that succeeded, this could lead to a hanging execute, eventually timing out with Error 4012 (`Request ndbd time-out, maybe due to high load or communication problems'). (Bug #12315582) * A memory leak in `LGMAN', that leaked 8 bytes of log buffer memory per 32k written, was introduced in MySQL Cluster NDB 7.0.9, effecting all MySQL Cluster NDB 7.1 releases as well as MySQL Cluster NDB 7.0.9 and later MySQL Cluster NDB 7.0 releases. (For example, when 128 MB log buffer memory was used, it was exhausted after writing 512 GB to the undo log.) This led to a GCP stop and data node failure. (Bug #60946) This regression was introduced by Bug #47966. * When using *Note `ndbmtd': mysql-cluster-programs-ndbmtd, a MySQL Cluster configured with 32 data nodes failed to start correctly. (Bug #60943) * When performing a TUP scan with locks in parallel, and with a highly concurrent load of inserts and deletions, the scan could sometimes fail to notice that a record had moved while waiting to acquire a lock on it, and so read the wrong record. During node recovery, this could lead to a crash of a node that was copying data to the node being started, and a possible forced shutdown of the cluster. * *Cluster API*: Performing interpreted operations using a unique index did not work correctly, because the interpret bit was kept when sending the lookup to the index table.  File: manual.info, Node: mysql-cluster-news-5-1-51-ndb-7-0-23, Next: mysql-cluster-news-5-1-51-ndb-7-0-22, Prev: mysql-cluster-news-5-1-56-ndb-7-0-24, Up: mysql-cluster-news-7-0 17.7.3.5 Changes in MySQL Cluster NDB 7.0.23 (5.1.51-ndb-7.0.23) (04 April 2011) ................................................................................ This release incorporates new features in the *Note `NDBCLUSTER': mysql-cluster. storage engine and fixes recently discovered bugs in MySQL Cluster NDB 7.0.22. Obtaining MySQL Cluster NDB 7.0 The latest MySQL Cluster NDB 7.0 binaries for supported platforms can be obtained from `http://dev.mysql.com/downloads/cluster/'. Source code for the latest MySQL Cluster NDB 7.0 release can be obtained from the same location. You can also access the MySQL Cluster NDB 7.0 development source tree at `https://code.launchpad.net/~mysql/mysql-server/mysql-cluster-7.0'. This release also incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.1, 6.2, 6.3, and 7.0 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.51 (see *Note news-5-1-51::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * Improved scaling of ordered index scans performance by removing a hard-coded limit (`MAX_PARALLEL_INDEX_SCANS_PER_FRAG') and making the number of `TUP' or `TUX' scans per fragment configurable by adding the `MaxParallelScansPerFragment' data node configuration parameter. (Bug #11769048) *Bugs fixed:* * *Important Change*: Formerly, the `--ndb-cluster-connection-pool' server option set a status variable as well as a system variable. The status variable has been removed as redundant. (Bug #60119) * A scan with a pushed condition (filter) using the `CommittedRead' lock mode could hang for a short interval when it was aborted when just as it had decided to send a batch. (Bug #11932525) * When aborting a multi-read range scan exactly as it was changing ranges in the local query handler, LQH could fail to detect it, leaving the scan hanging. (Bug #11929643) * Schema distribution did not take place for tables converted from another storage engine to *Note `NDB': mysql-cluster. using *Note `ALTER TABLE': alter-table.; this meant that such tables were not always visible to all SQL nodes attached to the cluster. (Bug #11894966) * A GCI value inserted by *Note `ndb_restore': mysql-cluster-programs-ndb-restore. `--restore_epoch' into the `ndb_apply_status' table was actually 1 less than the correct value. (Bug #11885852) * *Replication*: Error 1590 (`ER_SLAVE_INCIDENT') caused the slave to stop even when it was started with `--slave-skip-errors=1590'. (Bug #59889, Bug #11768580, Bug #11799671) * *Cluster Replication*: Filtering the binary log using `--binlog-ignore-db=mysql' caused epochs not to be logged as expected in the `ndb_apply_status' table. (Bug #11765707, Bug #58698) * *Disk Data*: Limits imposed by the size of `SharedGlobalMemory' were not always enforced consistently with regard to Disk Data undo buffers and log files. This could sometimes cause a *Note `CREATE LOGFILE GROUP': create-logfile-group. or *Note `ALTER LOGFILE GROUP': alter-logfile-group. statement to fail for no apparent reason, or cause the log file group specified by `InitialLogFileGroup' not to be created when starting the cluster. (Bug #57317) * The optimizer sometimes requested ordered access from a storage engine when ordered access was not required. (Bug #57601, Bug #11764737)  File: manual.info, Node: mysql-cluster-news-5-1-51-ndb-7-0-22, Next: mysql-cluster-news-5-1-51-ndb-7-0-21, Prev: mysql-cluster-news-5-1-51-ndb-7-0-23, Up: mysql-cluster-news-7-0 17.7.3.6 Changes in MySQL Cluster NDB 7.0.22 (5.1.51-ndb-7.0.22) (25 February 2011) ................................................................................... This release incorporates new features in the *Note `NDBCLUSTER': mysql-cluster. storage engine and fixes recently discovered bugs in MySQL Cluster NDB 7.0.21. Obtaining MySQL Cluster NDB 7.0 The latest MySQL Cluster NDB 7.0 binaries for supported platforms can be obtained from `http://dev.mysql.com/downloads/cluster/'. Source code for the latest MySQL Cluster NDB 7.0 release can be obtained from the same location. You can also access the MySQL Cluster NDB 7.0 development source tree at `https://code.launchpad.net/~mysql/mysql-server/mysql-cluster-7.0'. This release also incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.1, 6.2, 6.3, and 7.0 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.51 (see *Note news-5-1-51::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * *Disk Data*: The *Note `INFORMATION_SCHEMA.TABLES': tables-table. table now provides disk usage as well as memory usage information for Disk Data tables. Also, *Note `INFORMATION_SCHEMA.PARTITIONS': partitions-table, formerly did not show any statistics for *Note `NDB': mysql-cluster. tables. Now the `TABLE_ROWS', `AVG_ROW_LENGTH', `DATA_LENGTH', `MAX_DATA_LENGTH', and `DATA_FREE' columns contain correct information for the table's partitions. * A new `--rewrite-database' option is added for *Note `ndb_restore': mysql-cluster-programs-ndb-restore, which makes it possible to restore to a database having a different name from that of the database in the backup. For more information, see *Note mysql-cluster-programs-ndb-restore::. (Bug #54327) *Bugs fixed:* * *Important Note*: Due to an error in merging the original fix, it did not appear MySQL Cluster NDB 7.0.21; this oversight has been corrected in the current release. (Bug #58256) * This issue affects all previous MySQL Cluster NDB 7.0 releases. (Bug #60045) * *Note `ndb_restore `--rebuild-indexes'': mysql-cluster-programs-ndb-restore. caused multi-threaded index building to occur on the master node only. (Bug #59920) * Successive queries on the *Note `counters': mysql-cluster-ndbinfo-counters. table from the same SQL node returned unchanging results. To fix this issue, and to prevent similar issues from occurring in the future, *Note `ndbinfo': mysql-cluster-ndbinfo. tables are now excluded from the query cache. (Bug #59831) * When a *Note `CREATE TABLE': create-table. statement failed due to *Note `NDB': mysql-cluster. error 1224 (`Too many fragments'), it was not possible to create the table afterward unless either it had no ordered indexes, or a *Note `DROP TABLE': drop-table. statement was issued first, even if the subsequent *Note `CREATE TABLE': create-table. was valid and should otherwise have succeeded. (Bug #59756) See also Bug #59751. * When attempting to create a table on a MySQL Cluster with many standby data nodes (setting `Nodegroup=65536' in `config.ini' for the nodes that should wait, starting the nodes that should start immediately with the `--nowait-nodes' option, and using the *Note `CREATE TABLE': create-table. statement's `MAX_ROWS' option), *Note `mysqld': mysqld. miscalculated the number of fragments to use. This caused the *Note `CREATE TABLE': create-table. to fail. *Note*: The *Note `CREATE TABLE': create-table. failure caused by this issue in turn prevented any further attempts to create the table, even if the table structure was simplified or changed in such a way that the attempt should have succeeded. This `ghosting' issue is handled in BUG#59756. (Bug #59751) * *Note `NDB': mysql-cluster. sometimes treated a simple (not unique) ordered index as unique. (Bug #59519) * The logic used in determining whether to collapse a range to a simple equality was faulty. In certain cases, this could cause *Note `NDB': mysql-cluster. to treat a range as if it were a primary key lookup when determining the query plan to be used. Although this did not affect the actual result returned by the query, it could in such cases result in inefficient execution of queries due to the use of an inappropriate query plan. (Bug #59517) * When a query used multiple references to or instances of the same physical tables, *Note `NDB': mysql-cluster. failed to recognize these multiple instances as different tables; in such a case, *Note `NDB': mysql-cluster. could incorrectly use condition pushdown on a condition referring to these other instances to be pushed to the data nodes, even though the condition should have been rejected as unpushable, leading to invalid results. (Bug #58791) * *Cluster API*: When calling `NdbEventOperation::execute()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndbeventoperation-methods.html#ndb-ndbeventoperation-execute) during a node restart, it was possible to get a spurious error 711 (`System busy with node restart, schema operations not allowed when a node is starting'). (Bug #59723) * *Cluster API*: When an NDBAPI client application was waiting for more scan results after calling `NdbScanOperation::nextResult()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndbscanoperation-methods.html#ndb-ndbscanoperation-nextresult), the calling thread sometimes woke up even if no new batches for any fragment had arrived, which was unnecessary, and which could have a negative impact on the application's performance. (Bug #52298) * The `greedy' query plan optimizer failed to consider the size of intermediate query results when calculating the cost of a query. This could result in slowly executing queries when there are much faster execution plans available. (Bug #59326, Bug #11766256) * An `OUTER JOIN' query using `WHERE COLUMN IS NULL' could return an incorrect result. (Bug #58490, Bug #11765513) * For a query that used a subquery that included `GROUP BY' inside a `< ANY()' construct, no rows were returned when there should have been. (Bug #56690, Bug #11763918)  File: manual.info, Node: mysql-cluster-news-5-1-51-ndb-7-0-21, Next: mysql-cluster-news-5-1-51-ndb-7-0-20a, Prev: mysql-cluster-news-5-1-51-ndb-7-0-22, Up: mysql-cluster-news-7-0 17.7.3.7 Changes in MySQL Cluster NDB 7.0.21 (5.1.51-ndb-7.0.21) (26 January 2011) .................................................................................. This release incorporates new features in the *Note `NDBCLUSTER': mysql-cluster. storage engine and fixes recently discovered bugs in MySQL Cluster NDB 7.0.20. Obtaining MySQL Cluster NDB 7.0 The latest MySQL Cluster NDB 7.0 binaries for supported platforms can be obtained from `http://dev.mysql.com/downloads/cluster/'. Source code for the latest MySQL Cluster NDB 7.0 release can be obtained from the same location. You can also access the MySQL Cluster NDB 7.0 development source tree at `https://code.launchpad.net/~mysql/mysql-server/mysql-cluster-7.0'. This release also incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.1, 6.2, 6.3, and 7.0 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.51 (see *Note news-5-1-51::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * *Important Change*: The following changes have been made with regard to the `TimeBetweenEpochsTimeout' data node configuration parameter: * The maximum possible value for this parameter has been increased from 32000 milliseconds to 256000 milliseconds. * Setting this parameter to zero now has the effect of disabling GCP stops caused by save timeouts, commit timeouts, or both. * The current value of this parameter and a warning are written to the cluster log whenever a GCP save takes longer than 1 minute or a GCP commit takes longer than 10 seconds. For more information, see *Note mysql-cluster-ndbd-definition-gcp-stop-errors::. (Bug #58383) * Added the `--skip-broken-objects' option for *Note `ndb_restore': mysql-cluster-programs-ndb-restore. This option causes *Note `ndb_restore': mysql-cluster-programs-ndb-restore. to ignore tables corrupted due to missing blob parts tables, and to continue reading from the backup file and restoring the remaining tables. (Bug #54613) See also Bug #51652. * *Cluster Replication*: Added the `--ndb-log-apply-status' server option, which causes a replication slave to apply updates to the master's `mysql.ndb_apply_status' table to its own `ndb_apply_status' table using its own server ID in place of the master's server ID. This option can be useful in circular or chain replication setups when you need to track updates to `ndb_apply_status' as they propagate from one MySQL Cluster to the next in the circle or chain. * *Cluster API*: It is now possible to stop or restart a node even while other nodes are starting, using the MGM API `ndb_mgm_stop4()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-stop4.html) or `ndb_mgm_restart4()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-restart4.html) function, respectively, with the FORCE parameter set to 1. (Bug #58451) See also Bug #58319. *Bugs fixed:* * *Cluster API*: In some circumstances, very large *Note `BLOB': blob. read and write operations in MySQL Cluster applications can cause excessive resource usage and even exhaustion of memory. To fix this issue and to provide increased stability when performing such operations, it is now possible to set limits on the volume of *Note `BLOB': blob. data to be read or written within a given transaction in such a way that when these limits are exceeded, the current transaction implicitly executes any accumulated operations. This avoids an excessive buildup of pending data which can result in resource exhaustion in the NDB kernel. The limits on the amount of data to be read and on the amount of data to be written before this execution takes place can be configured separately. (In other words, it is now possible in MySQL Cluster to specify read batching and write batching that is specific to *Note `BLOB': blob. data.) These limits can be configured either on the NDB API level, or in the MySQL Server. On the NDB API level, four new methods are added to the `NdbTransaction' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndbtransaction.html#ndb-ndbtransaction) object. `getMaxPendingBlobReadBytes()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndbtransaction-methods.html#ndb-ndbtransaction-getmaxpendingblobreadbytes) and `setMaxPendingBlobReadBytes()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndbtransaction-methods.html#ndb-ndbtransaction-setmaxpendingblobreadbytes) can be used to get and to set, respectively, the maximum amount of *Note `BLOB': blob. data to be read that accumulates before this implicit execution is triggered. `getMaxPendingBlobWriteBytes()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndbtransaction-methods.html#ndb-ndbtransaction-getmaxpendingblobwritebytes) and `setMaxPendingBlobWriteBytes()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndbtransaction-methods.html#ndb-ndbtransaction-setmaxpendingblobwritebytes) can be used to get and to set, respectively, the maximum volume of *Note `BLOB': blob. data to be written that accumulates before implicit execution occurs. For the MySQL server, two new options are added. The `--ndb-blob-read-batch-bytes' option sets a limit on the amount of pending *Note `BLOB': blob. data to be read before triggering implicit execution, and the `--ndb-blob-write-batch-bytes' option controls the amount of pending *Note `BLOB': blob. data to be written. These limits can also be set using the *Note `mysqld': mysqld. configuration file, or read and set within the *Note `mysql': mysql. client and other MySQL client applications using the corresponding server system variables. (Bug #59113) * Two related problems could occur with read-committed scans made in parallel with transactions combining multiple (concurrent) operations: 1. When committing a multiple-operation transaction that contained concurrent insert and update operations on the same record, the commit arrived first for the insert and then for the update. If a read-committed scan arrived between these operations, it could thus read incorrect data; in addition, if the scan read variable-size data, it could cause the data node to fail. 2. When rolling back a multiple-operation transaction having concurrent delete and insert operations on the same record, the abort arrived first for the delete operation, and then for the insert. If a read-committed scan arrived between the delete and the insert, it could incorrectly assume that the record should not be returned (in other words, the scan treated the insert as though it had not yet been committed). (Bug #59496) * On Windows platforms, issuing a `SHUTDOWN' command in the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client caused management processes that had been started with the `--nodaemon' option to exit abnormally. (Bug #59437) * A row insert or update followed by a delete operation on the same row within the same transaction could in some cases lead to a buffer overflow. (Bug #59242) See also Bug #56524. This regression was introduced by Bug #35208. * Data nodes configured with very large amounts (multiple gigabytes) of `DiskPageBufferMemory' failed during startup with NDB error 2334 (`Job buffer congestion'). (Bug #58945) See also Bug #47984. * The `FAIL_REP' signal, used inside the NDB kernel to declare that a node has failed, now includes the node ID of the node that detected the failure. This information can be useful in debugging. (Bug #58904) * When executing a full table scan caused by a `WHERE' condition using `UNIQUE_KEY IS NULL' in combination with a join, *Note `NDB': mysql-cluster. failed to close the scan. (Bug #58750) See also Bug #57481. * Issuing *Note `EXPLAIN EXTENDED': explain. for a query that would use condition pushdown could cause *Note `mysqld': mysqld. to crash. (Bug #58553, Bug #11765570) * In some circumstances, an SQL trigger on an *Note `NDB': mysql-cluster. table could read stale data. (Bug #58538) * During a node takeover, it was possible in some circumstances for one of the remaining nodes to send an extra transaction confirmation (`LQH_TRANSCONF') signal to the `DBTC' kernel block, conceivably leading to a crash of the data node trying to take over as the new transaction coordinator. (Bug #58453) * A query having multiple predicates joined by `OR' in the `WHERE' clause and which used the `sort_union' access method (as shown using *Note `EXPLAIN': explain.) could return duplicate rows. (Bug #58280) * Trying to drop an index while it was being used to perform scan updates caused data nodes to crash. (Bug #58277, Bug #57057) * When handling failures of multiple data nodes, an error in the construction of internal signals could cause the cluster's remaining nodes to crash. This issue was most likely to affect clusters with large numbers of data nodes. (Bug #58240) * The functions `strncasecmp' and `strcasecmp' were declared in `ndb_global.h' but never defined or used. The declarations have been removed. (Bug #58204) * Some queries of the form *Note `SELECT ... WHERE COLUMN IN (SUBQUERY)': select. against an *Note `NDB': mysql-cluster. table could cause *Note `mysqld': mysqld. to hang in an endless loop. (Bug #58163) * The number of rows affected by a statement that used a `WHERE' clause having an `IN' condition with a value list containing a great many elements, and that deleted or updated enough rows such that *Note `NDB': mysql-cluster. processed them in batches, was not computed or reported correctly. (Bug #58040) * MySQL Cluster failed to compile correctly on FreeBSD 8.1 due to misplaced `#include' statements. (Bug #58034) * A query using `BETWEEN' as part of a pushed-down `WHERE' condition could cause mysqld to hang or crash. (Bug #57735) * Data nodes no longer allocated all memory prior to being ready to exchange heartbeat and other messages with management nodes, as in NDB 6.3 and earlier versions of MySQL Cluster. This caused problems when data nodes configured with large amounts of memory failed to show as connected or showed as being in the wrong start phase in the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client even after making their initial connections to and fetching their configuration data from the management server. With this fix, data nodes now allocate all memory as they did in earlier MySQL Cluster versions. (Bug #57568) * In some circumstances, it was possible for *Note `mysqld': mysqld. to begin a new multi-range read scan without having closed a previous one. This could lead to exhaustion of all scan operation objects, transaction objects, or lock objects (or some combination of these) in *Note `NDB': mysql-cluster, causing queries to fail with such errors as `Lock wait timeout exceeded' or `Connect failure - out of connection objects'. (Bug #57481) See also Bug #58750. * Queries using `COLUMN IS' [`NOT'] `NULL' on a table with a unique index created with `USING HASH' on COLUMN always returned an empty result. (Bug #57032) * With `engine_condition_pushdown' enabled, a query using `LIKE' on an *Note `ENUM': enum. column of an *Note `NDB': mysql-cluster. table failed to return any results. This issue is resolved by disabling `engine_condition_pushdown' when performing such queries. (Bug #53360) * When a slash character (`/') was used as part of the name of an index on an *Note `NDB': mysql-cluster. table, attempting to execute a *Note `TRUNCATE TABLE': truncate-table. statement on the table failed with the error `Index not found', and the table was rendered unusable. (Bug #38914) * *Disk Data*: *Partitioning*: When using multi-threaded data nodes, an *Note `NDB': mysql-cluster. table created with a very large value for the `MAX_ROWS' option could--if this table was dropped and a new table with fewer partitions, but having the same table ID, was created--cause *Note `ndbmtd': mysql-cluster-programs-ndbmtd. to crash when performing a system restart. This was because the server attempted to examine each partition whether or not it actually existed. This issue is the same as that reported in Bug#45154, except that the current issue is specific to *Note `ndbmtd': mysql-cluster-programs-ndbmtd. instead of *Note `ndbd': mysql-cluster-programs-ndbd. (Bug #58638) * *Disk Data*: In certain cases, a race condition could occur when *Note `DROP LOGFILE GROUP': drop-logfile-group. removed the logfile group while a read or write of one of the effected files was in progress, which in turn could lead to a crash of the data node. (Bug #59502) * *Disk Data*: A race condition could sometimes be created when *Note `DROP TABLESPACE': drop-tablespace. was run concurrently with a local checkpoint; this could in turn lead to a crash of the data node. (Bug #59501) * *Disk Data*: Performing what should have been an online drop of a multi-column index was actually performed offline. (Bug #55618) * *Disk Data*: When at least one data node was not running, queries against the *Note `INFORMATION_SCHEMA.FILES': files-table. table took an excessive length of time to complete because the MySQL server waited for responses from any stopped nodes to time out. Now, in such cases, MySQL does not attempt to contact nodes which are not known to be running. (Bug #54199) * *Cluster Replication*: When a *Note `mysqld': mysqld. performing replication of a MySQL Cluster that uses *Note `ndbmtd': mysql-cluster-programs-ndbmtd. is forcibly disconnected (thus causing an `API_FAIL_REQ' signal to be sent), the `SUMA' kernel block iterates through all active subscriptions and disables them. If a given subscription has no more active users, then this subscription is also deactivated in the `DBTUP' kernel block. This process had no flow control, and when there were many subscriptions being deactivated (more than 512), this could cause an overflow in the short-time queue defined in the `DbtupProxy' class. The fix for this problem includes implementing proper flow control for this deactivation process and increasing the size of the short-time queue in `DbtupProxy'. (Bug #58693) * *Cluster API*: It was not possible to obtain the status of nodes accurately after an attempt to stop a data node using `ndb_mgm_stop()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-stop.html) failed without returning an error. (Bug #58319) * *Cluster API*: Attempting to read the same value (using `getValue()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndboperation-methods.html#ndb-ndboperation-getvalue)) more than 9000 times within the same transaction caused the transaction to hang when executed. Now when more reads are performed in this way than can be accommodated in a single transaction, the call to `execute()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndbtransaction-methods.html#ndb-ndbtransaction-execute) fails with a suitable error. (Bug #58110) * A `NOT IN' predicate with a subquery containing a `HAVING' clause could retrieve too many rows, when the subquery itself returned `NULL'. (Bug #58818, Bug #11765815) * `WHERE' conditions of the following forms were evaluated incorrectly and could return incorrect results: WHERE NULL-VALUED-CONST-EXPRESSION NOT IN (SUBQUERY) WHERE NULL-VALUED-CONST-EXPRESSION IN (SUBQUERY) IS UNKNOWN (Bug #58628, Bug #11765642) * `WHERE' conditions of the following form were evaluated incorrectly and could return incorrect results: WHERE COLUMN IN (SUBQUERY) IS UNKNOWN (Bug #58626) * Outer joins with an empty table could produce incorrect results. (Bug #58422, Bug #11765451) * Condition pushdown optimization could push down conditions with incorrect column references. (Bug #58134, Bug #11765196) * Outer joins on a unique key could return incorrect results. (Bug #57034, Bug #11764219)  File: manual.info, Node: mysql-cluster-news-5-1-51-ndb-7-0-20a, Next: mysql-cluster-news-5-1-51-ndb-7-0-20, Prev: mysql-cluster-news-5-1-51-ndb-7-0-21, Up: mysql-cluster-news-7-0 17.7.3.8 Changes in MySQL Cluster NDB 7.0.20a (5.1.51-ndb-7.0.20a) (18 November 2010) ..................................................................................... MySQL Cluster NDB 7.0.20a is a new release of MySQL Cluster which fixes a critical upgrade issue discovered in MySQL Cluster NDB 7.0.20 shortly after it was released. It is otherwise identical to MySQL Cluster NDB 7.0.20. Obtaining MySQL Cluster NDB 7.0 The latest MySQL Cluster NDB 7.0 binaries for supported platforms can be obtained from `http://dev.mysql.com/downloads/cluster/'. Source code for the latest MySQL Cluster NDB 7.0 release can be obtained from the same location. You can also access the MySQL Cluster NDB 7.0 development source tree at `https://code.launchpad.net/~mysql/mysql-server/mysql-cluster-7.0'. This release also incorporates all bugfixes and changes made in previous MySQL Cluster releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.51 (see *Note news-5-1-51::). *Bugs fixed:* * *Important Note*: Issuing an `ALL DUMP' command during a rolling upgrade to MySQL Cluster NDB 7.0.20 caused the cluster to crash. (Bug #58256)  File: manual.info, Node: mysql-cluster-news-5-1-51-ndb-7-0-20, Next: mysql-cluster-news-5-1-47-ndb-7-0-19, Prev: mysql-cluster-news-5-1-51-ndb-7-0-20a, Up: mysql-cluster-news-7-0 17.7.3.9 Changes in MySQL Cluster NDB 7.0.20 (5.1.51-ndb-7.0.20) (08 November 2010) ................................................................................... This release incorporates new features in the *Note `NDBCLUSTER': mysql-cluster. storage engine and fixes recently discovered bugs in MySQL Cluster NDB 7.0.19. *Important*: A critical upgrade issue was discovered in MySQL Cluster NDB 7.0.20 shortly after release, causing it to be withdrawn and replaced with MySQL Cluster NDB 7.0.20a, which contains a fix for this issue. MySQL Cluster NDB 7.0.20a is otherwise identical to MySQL Cluster 7.0.20. See *Note mysql-cluster-news-5-1-51-ndb-7-0-20a::, for more information. Obtaining MySQL Cluster NDB 7.0 The latest MySQL Cluster NDB 7.0 binaries for supported platforms can be obtained from `http://dev.mysql.com/downloads/cluster/'. Source code for the latest MySQL Cluster NDB 7.0 release can be obtained from the same location. You can also access the MySQL Cluster NDB 7.0 development source tree at `https://code.launchpad.net/~mysql/mysql-server/mysql-cluster-7.0'. This release also incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.1, 6.2, 6.3, and 7.0 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.51 (see *Note news-5-1-51::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * *Important Change*: *Note `ndbd': mysql-cluster-programs-ndbd. now bypasses use of Non-Uniform Memory Access support on Linux hosts by default. If your system supports NUMA, you can enable it and override *Note `ndbd': mysql-cluster-programs-ndbd. use of interleaving by setting the `Numa' data node configuration parameter which is added in this release. See Defining Data Nodes: Realtime Performance Parameters, for more information. (Bug #57807) * *Important Change*: The `Id' configuration parameter used with MySQL Cluster management, data, and API nodes (including SQL nodes) is now deprecated, and the `NodeId' parameter (long available as a synonym for `Id' when configuring these types of nodes) should be used instead. `Id' continues to be supported for reasons of backward compatibility, but now generates a warning when used with these types of nodes, and is subject to removal in a future release of MySQL Cluster. This change affects the name of the configuration parameter only, establishing a clear preference for `NodeId' over `Id' in the `[mgmd]', `[ndbd]', `[mysql]', and `[api]' sections of the MySQL Cluster global configuration (`config.ini') file. The behavior of unique identifiers for management, data, and SQL and API nodes in MySQL Cluster has not otherwise been altered. The `Id' parameter as used in the `[computer]' section of the MySQL Cluster global configuration file is not affected by this change. *Bugs fixed:* * *Packaging*: MySQL Cluster RPM distributions did not include a `shared-compat' RPM for the MySQL Server, which meant that MySQL applications depending on `libmysqlclient.so.15' (MySQL 5.0 and earlier) no longer worked. (Bug #38596) * On Windows, the angel process which monitors and (when necessary) restarts the data node process failed to spawn a new worker in some circumstances where the arguments vector contained extra items placed at its beginning. This could occur when the path to *Note `ndbd.exe': mysql-cluster-programs-ndbd. or *Note `ndbmtd.exe': mysql-cluster-programs-ndbmtd. contained one or more spaces. (Bug #57949) * The disconnection of an API or management node due to missed heartbeats led to a race condition which could cause data nodes to crash. (Bug #57946) * The method for calculating table schema versions used by schema transactions did not follow the established rules for recording schemas used in the `P0.SchemaLog' file. (Bug #57897) See also Bug #57896. * The `LQHKEYREQ' request message used by the local query handler when checking the major schema version of a table, being only 16 bits wide, could cause this check to fail with an `Invalid schema version' error (*Note `NDB': mysql-cluster. error code 1227). This issue occurred after creating and dropping (and re-creating) the same table 65537 times, then trying to insert rows into the table. (Bug #57896) See also Bug #57897. * Data nodes compiled with `gcc' 4.5 or higher crashed during startup. (Bug #57761) * Transient errors during a local checkpoint were not retried, leading to a crash of the data node. Now when such errors occur, they are retried up to 10 times if necessary. (Bug #57650) * *Note `ndb_restore': mysql-cluster-programs-ndb-restore. now retries failed transactions when replaying log entries, just as it does when restoring data. (Bug #57618) * The `SUMA' kernel block has a 10-element ring buffer for storing out-of-order `SUB_GCP_COMPLETE_REP' signals received from the local query handlers when global checkpoints are completed. In some cases, exceeding the ring buffer capacity on all nodes of a node group at the same time caused the node group to fail with an assertion. (Bug #57563) * During a GCP takeover, it was possible for one of the data nodes not to receive a `SUB_GCP_COMPLETE_REP' signal, with the result that it would report itself as `GCP_COMMITTING' while the other data nodes reported `GCP_PREPARING'. (Bug #57522) * Specifying a *Note `WHERE': select. clause of the form `RANGE1 OR RANGE2' when selecting from an *Note `NDB': mysql-cluster. table having a primary key on multiple columns could result in Error 4259 `Invalid set of range scan bounds' if RANGE2 started exactly where RANGE1 ended and the primary key definition declared the columns in a different order relative to the order in the table's column list. (Such a query should simply return all rows in the table, since any expression `VALUE < CONSTANT OR VALUE >= CONSTANT' is always true.) Example Suppose `t' is an *Note `NDB': mysql-cluster. table defined by the following *Note `CREATE TABLE': create-table. statement: CREATE TABLE t (a, b, PRIMARY KEY (b, a)) ENGINE NDB; This issue could then be triggered by a query such as this one: SELECT * FROM t WHERE b < 8 OR b >= 8; In addition, the order of the ranges in the `WHERE' clause was significant; the issue was not triggered, for example, by the query *Note `SELECT * FROM t WHERE b <= 8 OR b > 8': select. (Bug #57396) * A number of cluster log warning messages relating to deprecated configuration parameters contained spelling, formatting, and other errors. (Bug #57381) * The `MAX_ROWS' option for *Note `CREATE TABLE': create-table. was ignored, which meant that it was not possible to enable multi-threaded building of indexes. (Bug #57360) * A GCP stop is detected using 2 parameters which determine the maximum time that a global checkpoint or epoch can go unchanged; one of these controls this timeout for GCPs and one controls the timeout for epochs. Suppose the cluster is configured such that `TimeBetweenEpochsTimeout' is 100 ms but `HeartbeatIntervalDbDb' is 1500 ms. A node failure can be signalled after 4 missed heartbeats--in this case, 6000 ms. However, this would exceed `TimeBetweenEpochsTimeout', causing false detection of a GCP. To prevent this from happening, the configured value for `TimeBetweenEpochsTimeout' is automatically adjusted, based on the values of `HeartbeatIntervalDbDb' and `ArbitrationTimeout'. The current issue arose when the automatic adjustment routine did not correctly take into consideration the fact that, during cascading node-failures, several intervals of length `4 * (HeartbeatIntervalDBDB + ArbitrationTimeout)' may elapse before all node failures have internally been resolved. This could cause false GCP detection in the event of a cascading node failure. (Bug #57322) * Successive `CREATE NODEGROUP' and `DROP NODEGROUP' commands could cause *Note `mysqld': mysqld. processes to crash. (Bug #57164) * Queries using `WHERE VARCHAR_PK_COLUMN LIKE 'PATTERN%'' or `WHERE VARCHAR_PK_COLUMN LIKE 'PATTERN_'' against an *Note `NDB': mysql-cluster. table having a *Note `VARCHAR': char. column as its primary key failed to return all matching rows. (Bug #56853) * Aborting a native `NDB' backup in the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client using the `ABORT BACKUP' command did not work correctly when using *Note `ndbmtd': mysql-cluster-programs-ndbmtd, in some cases leading to a crash of the cluster. (Bug #56285) * When a data node angel process failed to fork off a new worker process (to replace one that had failed), the failure was not handled. This meant that the angel process either transformed itself into a worker process, or itself failed. In the first case, the data node continued to run, but there was no longer any angel to restart it in the event of failure, even with `StopOnError' set to 0. (Bug #53456) * *Partitioning*: Trying to use the same column more than once in the partitioning key when partitioning a table by `KEY' caused *Note `mysqld': mysqld. to crash. Such duplication of key columns is now expressly disallowed, and fails with an appropriate error. (Bug #53354, Bug #57924) * *Disk Data*: When performing online DDL on Disk Data tables, scans and moving of the relevant tuples were done in more or less random order. This fix causes these scans to be done in the order of the tuples, which should improve performance of such operations due to the more sequential ordering of the scans. (Bug #57848) See also Bug #57827. * *Disk Data*: Adding unique indexes to *Note `NDB': mysql-cluster. Disk Data tables could take an extremely long time. This was particularly noticeable when using *Note `ndb_restore `--rebuild-indexes'': mysql-cluster-programs-ndb-restore. (Bug #57827) * *Cluster Replication*: The `OPTION_ALLOW_BATCHING' bitmask had the same value as `OPTION_PROFILING'. This caused conflicts between using `--slave-allow-batching' and profiling. (Bug #57603) * *Cluster Replication*: Replication of *Note `SET': set. and *Note `ENUM': enum. columns represented using more than 1 byte (that is, *Note `SET': set. columns with more than 8 members and *Note `ENUM': enum. columns with more than 256 constants) between platforms using different endianness failed when using the row-based format. This was because columns of these types are represented internally using integers, but the internal functions used by MySQL to handle them treated them as strings. (Bug #52131) See also Bug #53528. * *Cluster API*: An application dropping a table at the same time that another application tried to set up a replication event on the same table could lead to a crash of the data node. The same issue could sometimes cause `NdbEventOperation::execute()' to hang. (Bug #57886) * *Cluster API*: An NDB API client program under load could abort with an assertion error in `TransporterFacade::remove_from_cond_wait_queue'. (Bug #51775) See also Bug #32708.  File: manual.info, Node: mysql-cluster-news-5-1-47-ndb-7-0-19, Next: mysql-cluster-news-5-1-47-ndb-7-0-18, Prev: mysql-cluster-news-5-1-51-ndb-7-0-20, Up: mysql-cluster-news-7-0 17.7.3.10 Changes in MySQL Cluster NDB 7.0.19 (5.1.47-ndb-7.0.19) (08 October 2010) ................................................................................... This release incorporates new features in the *Note `NDBCLUSTER': mysql-cluster. storage engine and fixes recently discovered bugs in MySQL Cluster NDB 7.0.18. Obtaining MySQL Cluster NDB 7.0 The latest MySQL Cluster NDB 7.0 binaries for supported platforms can be obtained from `http://dev.mysql.com/downloads/cluster/'. Source code for the latest MySQL Cluster NDB 7.0 release can be obtained from the same location. You can also access the MySQL Cluster NDB 7.0 development source tree at `https://code.launchpad.net/~mysql/mysql-server/mysql-cluster-7.0'. This release also incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.1, 6.2, 6.3, and 7.0 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.47 (see *Note news-5-1-47::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * *Note `mysqldump': mysqldump. as supplied with MySQL Cluster now has an `--add-drop-trigger' option which adds a *Note `DROP TRIGGER IF EXISTS': drop-trigger. statement before each dumped trigger definition. (Bug #55691) See also Bug #34325, Bug #11747863. * It is now possible using the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. management client or the MGM API to force a data node shutdown or restart even if this would force the shutdown or restart of the entire cluster. In the management client, this is implemented through the addition of the `-f' (force) option to the `STOP' and `RESTART' commands. For more information, see *Note mysql-cluster-mgm-client-commands::. The MGM API also adds two new methods for forcing such a node shutdown or restart; see `ndb_mgm_stop4()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-stop4.html), and `ndb_mgm_restart4()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-restart4.html), for more information about these methods. (Bug #54226) * *Cluster API*: The MGM API function `ndb_mgm_get_version()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-get-version.html), which was previously internal, has now been moved to the public API. This function can be used to get `NDB' storage engine and other version information from the management server. (Bug #51310) See also Bug #51273. *Bugs fixed:* * At startup, an *Note `ndbd': mysql-cluster-programs-ndbd. or *Note `ndbmtd': mysql-cluster-programs-ndbmtd. process creates directories for its file system without checking to see whether they already exist. Portability code added in MySQL Cluster NDB 7.0.18 and MySQL Cluster NDB 7.1.7 did not account for this fact, printing a spurious error message when a directory to be created already existed. This unneeded printout has been removed. (Bug #57087) * A data node can be shut down having completed and synchronized a given GCI X, while having written a great many log records belonging to the next GCI X + 1, as part of normal operations. However, when starting, completing, and synchronizing GCI X + 1, then the log records from original start must not be read. To make sure that this does not happen, the REDO log reader finds the last GCI to restore, scans forward from that point, and erases any log records that were not (and should never be) used. The current issue occurred because this scan stopped immediately as soon as it encountered an empty page. This was problematic because the REDO log is divided into several files; thus, it could be that there were log records in the beginning of the next file, even if the end of the previous file was empty. These log records were never invalidated; following a start or restart, they could be reused, leading to a corrupt REDO log. (Bug #56961) * An error in program flow in `ndbd.cpp' could result in data node shutdown routines being called multiple times. (Bug #56890) * Under certain rare conditions, attempting to start more than one *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. process simultaneously using the `--reload' option caused a race condition such that none of the *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. processes could start. (Bug #56844) * When distributing *Note `CREATE TABLE': create-table. and *Note `DROP TABLE': drop-table. operations among several SQL nodes attached to a MySQL Cluster. the `LOCK_OPEN' lock normally protecting *Note `mysqld': mysqld.'s internal table list is released so that other queries or DML statements are not blocked. However, to make sure that other DDL is not executed simultaneously, a global schema lock (implemented as a row-level lock by `NDB') is used, such that all operations that can modify the state of the *Note `mysqld': mysqld. internal table list also need to acquire this global schema lock. The *Note `SHOW TABLE STATUS': show-table-status. statement did not acquire this lock. (Bug #56841) * In certain cases, *Note `DROP DATABASE': drop-database. could sometimes leave behind a cached table object, which caused problems with subsequent DDL operations. (Bug #56840) * Memory pages used for `DataMemory', once assigned to ordered indexes, were not ever freed, even after any rows that belonged to the corresponding indexes had been deleted. (Bug #56829) * MySQL Cluster stores, for each row in each `NDB' table, a Global Checkpoint Index (GCI) which identifies the last committed transaction that modified the row. As such, a GCI can be thought of as a coarse-grained row version. Due to changes in the format used by `NDB' to store local checkpoints (LCPs) in MySQL Cluster NDB 6.3.11, it could happen that, following cluster shutdown and subsequent recovery, the GCI values for some rows could be changed unnecessarily; this could possibly, over the course of many node or system restarts (or both), lead to an inconsistent database. (Bug #56770) * When multiple SQL nodes were connected to the cluster and one of them stopped in the middle of a DDL operation, the *Note `mysqld': mysqld. process issuing the DDL timed out with the error `distributing TBL_NAME timed out. Ignoring'. (Bug #56763) * An online *Note `ALTER TABLE ... ADD COLUMN': alter-table. operation that changed the table schema such that the number of 32-bit words used for the bitmask allocated to each DML operation increased during a transaction in DML which was performed prior to DDL which was followed by either another DML operation or--if using replication--a commit, led to data node failure. This was because the data node did not take into account that the bitmask for the before-image was smaller than the current bitmask, which caused the node to crash. (Bug #56524) * On Windows, a data node refused to start in some cases unless the *Note `ndbd.exe': mysql-cluster-programs-ndbd. executable was invoked using an absolute rather than a relative path. (Bug #56257) * The text file `cluster_change_hist.txt' containing old MySQL Cluster changelog information was no longer being maintained, and so has been removed from the tree. (Bug #56116) * The failure of a data node during some scans could cause other data nodes to fail. (Bug #54945) * Exhausting the number of available commit-ack markers (controlled by the `MaxNoOfConcurrentTransactions' parameter) led to a data node crash. (Bug #54944) * When running a *Note `SELECT': select. on an *Note `NDB': mysql-cluster. table with *Note `BLOB': blob. or *Note `TEXT': blob. columns, memory was allocated for the columns but was not freed until the end of the *Note `SELECT': select. This could cause problems with excessive memory usage when dumping (using for example *Note `mysqldump': mysqldump.) tables with such columns and having many rows, large column values, or both. (Bug #52313) See also Bug #56488, Bug #50310. * *Cluster Replication*: When an SQL node starts, as part of setting up replication, it subscribes to data events from all data nodes using a `SUB_START_REQ' (subscription start request) signal. Atomicity of `SUB_START_REQ' is implemented such that, if any of the nodes returns an error, a `SUB_STOP_REQ' (subscription stop request) is sent to any nodes that replied with a `SUB_START_CONF' (subscription start confirmation). However, if all data nodes returned an error, `SUB_STOP_REQ' was not sent to any of them. This caused mysqld to hang when restarting (while waiting for a response), and subsequent data node restarts to hang as well. (Bug #56579) * *Cluster Replication*: When a *Note `mysqld': mysqld. process was shut down while it was still performing updates, it was possible for the entry containing binary log information for the final epoch preceding shutdown to be omitted from the `mysql.ndb_binlog_index' table. This could somtimes occur even during a normal shutdown of *Note `mysqld': mysqld. (Bug #55909) * *Cluster Replication*: The graceful shutdown of a data node in the master cluster could sometimes cause rows to be skipped when writing transactions to the binary log. Testing following an initial fix for this issue revealed an additional case where the graceful shutdown of a data node was not handled properly. The current fix addresses this case. (Bug #55641) See also Bug #18538. * *Cluster API*: The MGM API functions `ndb_mgm_stop()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-stop.html) and `ndb_mgm_restart()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-restart.html) set the error code and message without first checking whether the management server handle was `NULL', which could lead to fatal errors in MGM API applications that depended on these functions. (Bug #57089) * *Cluster API*: The MGM API function `ndb_mgm_get_version()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-get-version.html) did not set the error message before returning with an error. With this fix, it is now possible to call `ndb_mgm_get_latest_error()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-get-latest-error.html) after a failed call to this function such that `ndb_mgm_get_latest_error()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-get-latest-error.html) returns an error number and error message, as expected of MGM API calls. (Bug #57088)  File: manual.info, Node: mysql-cluster-news-5-1-47-ndb-7-0-18, Next: mysql-cluster-news-5-1-47-ndb-7-0-17, Prev: mysql-cluster-news-5-1-47-ndb-7-0-19, Up: mysql-cluster-news-7-0 17.7.3.11 Changes in MySQL Cluster NDB 7.0.18 (5.1.47-ndb-7.0.18) (03 September 2010) ..................................................................................... This release incorporates new features in the *Note `NDBCLUSTER': mysql-cluster. storage engine and fixes recently discovered bugs in MySQL Cluster NDB 7.0.17. Obtaining MySQL Cluster NDB 7.0 The latest MySQL Cluster NDB 7.0 binaries for supported platforms can be obtained from `http://dev.mysql.com/downloads/cluster/'. Source code for the latest MySQL Cluster NDB 7.0 release can be obtained from the same location. You can also access the MySQL Cluster NDB 7.0 development source tree at `https://code.launchpad.net/~mysql/mysql-server/mysql-cluster-7.0'. This release also incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.1, 6.2, 6.3, and 7.0 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.47 (see *Note news-5-1-47::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * *Important Change*: More finely-grained control over restart-on-failure behavior is provided with two new data node configuration parameters `MaxStartFailRetries' and `StartFailRetryDelay'. `MaxStartFailRetries' limits the total number of retries made before giving up on starting the data node; `StartFailRetryDelay' sets the number of seconds between retry attempts. These parameters are used only if `StopOnError' is set to 0. For more information, see *Note mysql-cluster-ndbd-definition::. (Bug #54341) *Bugs fixed:* * *Note `ndb_restore': mysql-cluster-programs-ndb-restore. always reported 0 for the `GCPStop' (end point of the backup). Now it provides useful binary log position and epoch information. (Bug #56298) * The `LockExecuteThreadToCPU' configuration parameter was not handled correctly for CPU ID values greater than 255. (Bug #56185) * Following a failure of the master data node, the new master sometimes experienced a race condition which caused the node to terminate with a GcpStop error. (Bug #56044) * Trying to create a table having a *Note `BLOB': blob. or *Note `TEXT': blob. column with `DEFAULT ''' failed with the error `Illegal null attribute'. (An empty default is allowed and ignored by *Note `MyISAM': myisam-storage-engine.; *Note `NDB': mysql-cluster. should do the same.) (Bug #55121) * *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. `--nodaemon' logged to the console in addition to the configured log destination. (Bug #54779) * The warning `MaxNoOfExecutionThreads (#) > LockExecuteThreadToCPU count (#), this could cause contention' could be logged when running *Note `ndbd': mysql-cluster-programs-ndbd, even though the condition described can occur only when using *Note `ndbmtd': mysql-cluster-programs-ndbmtd. (Bug #54342) * Startup messages previously written by *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. to `stdout' are now written to the cluster log instead when `LogDestination' is set. (Bug #47595) * The graceful shutdown of a data node could sometimes cause transactions to be aborted unnecessarily. (Bug #18538) See also Bug #55641. * *Cluster Replication*: The graceful shutdown of a data node in the master cluster could sometimes cause rows to be skipped when writing transactions to the binary log, leading to an inconsistent slave cluster. (Bug #55641) See also Bug #18538. * *Cluster Replication*: Specifying the `--expire_logs_days' option when there were old binary logs to delete caused SQL nodes to crash on startup. (Bug #41751)  File: manual.info, Node: mysql-cluster-news-5-1-47-ndb-7-0-17, Next: mysql-cluster-news-5-1-47-ndb-7-0-16, Prev: mysql-cluster-news-5-1-47-ndb-7-0-18, Up: mysql-cluster-news-7-0 17.7.3.12 Changes in MySQL Cluster NDB 7.0.17 (5.1.47-ndb-7.0.17) (16 August 2010) .................................................................................. This release incorporates new features in the *Note `NDBCLUSTER': mysql-cluster. storage engine and fixes recently discovered bugs in MySQL Cluster NDB 7.0.16. Obtaining MySQL Cluster NDB 7.0.17 The latest MySQL Cluster NDB 7.0 binaries for supported platforms can be obtained from `http://dev.mysql.com/downloads/cluster/'. Source code for the latest MySQL Cluster NDB 7.0 release can be obtained from the same location. You can also access the MySQL Cluster NDB 7.0 development source tree at `https://code.launchpad.net/~mysql/mysql-server/mysql-cluster-7.0'. This release also incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.1, 6.2, 6.3, and 7.0 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.47 (see *Note news-5-1-47::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * Added the `DictTrace' data node configuration parameter, for use in debugging *Note `NDB': mysql-cluster. code. For more information, see *Note mysql-cluster-ndbd-definition::. (Bug #55963) * Added the `--server-id-bits' option for mysqld and mysqlbinlog. For *Note `mysqld': mysqld, the `--server-id-bits' option indicates the number of least significant bits within the 32-bit server ID which actually identify the server. Indicating that the server ID uses less than 32 bits permits the remaining bits to be used for other purposes by NDB API applications using the Event API and `OperationOptions::AnyValue'. For *Note `mysqlbinlog': mysqlbinlog, the `--server-id-bits' option tells *Note `mysqlbinlog': mysqlbinlog. how to interpret the server IDs in the binary log when the binary log was written by a *Note `mysqld': mysqld. having its `server_id_bits' set to less than the maximum (32). (Bug #52305) *Bugs fixed:* * *Cluster API*: *Important Change*: The poll and select calls made by the MGM API were not interrupt-safe; that is, a signal caught by the process while waiting for an event on one or more sockets returned error -1 with `errno' set to EINTR. This caused problems with MGM API functions such as `ndb_logevent_get_next()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-logevent-get-next.html) and `ndb_mgm_get_status2()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-get-status2.html). To fix this problem, the internal `ndb_socket_poller::poll()' function has been made EINTR-safe. The old version of this function has been retained as `poll_unsafe()', for use by those parts of NDB that do not need the EINTR-safe version of the function. (Bug #55906) * The TCP configuration parameters `HostName1' and `HostName2' were not displayed in the output of *Note `ndb_config': mysql-cluster-programs-ndb-config. `--configinfo'. (Bug #55839) * When another data node failed, a given data node `DBTC' kernel block could time out while waiting for `DBDIH' to signal commits of pending transactions, leading to a crash. Now in such cases the timeout generates a prinout, and the data node continues to operate. (Bug #55715) * Starting *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. with `--config-cache=0' caused it to leak memory. (Bug #55205) * The `configure.js' option `WITHOUT_DYNAMIC_PLUGINS=TRUE' was ignored when building MySQL Cluster for Windows using `CMake'. Among the effects of this issue was that `CMake' attempted to build the `InnoDB' storage engine as a plugin (`.DLL' file) even though the `InnoDB Plugin' is not currently supported by MySQL Cluster. (Bug #54913) * It was possible for a *Note `DROP DATABASE': drop-database. statement to remove *Note `NDB': mysql-cluster. hidden blob tables without removing the parent tables, with the result that the tables, although hidden to MySQL clients, were still visible in the output of *Note `ndb_show_tables': mysql-cluster-programs-ndb-show-tables. but could not be dropped using *Note `ndb_drop_table': mysql-cluster-programs-ndb-drop-table. (Bug #54788) * An excessive number of timeout warnings (normally used only for debugging) were written to the data node logs. (Bug #53987) * *Disk Data*: As an optimization when inserting a row to an empty page, the page is not read, but rather simply initialized. However, this optimzation was performed in all cases when an empty row was inserted, even though it should have been done only if it was the first time that the page had been used by a table or fragment. This is because, if the page had been in use, and then all records had been released from it, the page still needed to be read to learn its log sequence number (LSN). This caused problems only if the page had been flushed using an incorrect LSN and the data node failed before any local checkpoint was completed--which would removed any need to apply the undo log, hence the incorrect LSN was ignored. The user-visible result of the incorrect LSN was that it caused the data node to fail during a restart. It was perhaps also possible (although not conclusively proven) that this issue could lead to incorrect data. (Bug #54986) * *Cluster API*: Calling `NdbTransaction::refresh()' did not update the timer for `TransactionInactiveTimeout'. (Bug #54724)  File: manual.info, Node: mysql-cluster-news-5-1-47-ndb-7-0-16, Next: mysql-cluster-news-5-1-44-ndb-7-0-15b, Prev: mysql-cluster-news-5-1-47-ndb-7-0-17, Up: mysql-cluster-news-7-0 17.7.3.13 Changes in MySQL Cluster NDB 7.0.16 (5.1.47-ndb-7.0.16) (25 June 2010) ................................................................................ This release incorporates new features in the *Note `NDBCLUSTER': mysql-cluster. storage engine and fixes recently discovered bugs in MySQL Cluster NDB 7.0.15. This release also incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.1, 6.2, 6.3, and 7.0 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.47 (see *Note news-5-1-47::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * Restrictions on some types of mismatches in column definitions when restoring data using *Note `ndb_restore': mysql-cluster-programs-ndb-restore. have been relaxed. These include the following types of mismatches: * Different `COLUMN_FORMAT' settings (`FIXED', `DYNAMIC', `DEFAULT') * Different `STORAGE' settings (`MEMORY', `DISK') * Different default values * Different distribution key settings Now, when one of these types of mismatches in column definitions is encountered, *Note `ndb_restore': mysql-cluster-programs-ndb-restore. no longer stops with an error; instead, it accepts the data and inserts it into the target table, while issuing a warning to the user. For more information, see *Note mysql-cluster-programs-ndb-restore::. (Bug #54423) See also Bug #53810, Bug #54178, Bug #54242, Bug #54279. * Introduced the `HeartbeatOrder' data node configuration parameter, which can be used to set the order in which heartbeats are transmitted between data nodes. This parameter can be useful in situations where multiple data nodes are running on the same host and a temporary disruption in connectivity between hosts would otherwise cause the loss of a node group, leading to failure of the cluster. (Bug #52182) * It is now possible to install management node and data node processes as Windows services. (See *Note mysql-cluster-install-windows-service::, for more information.) In addition, data node processes on Windows are now maintained by angel processes, just as they are on other platforms supported by MySQL Cluster. *Bugs fixed:* * The disconnection of all API nodes (including SQL nodes) during an *Note `ALTER TABLE': alter-table. caused a memory leak. (Bug #54685) * If a node shutdown (either in isolation or as part of a system shutdown) occurred directly following a local checkpoint, it was possible that this local checkpoint would not be used when restoring the cluster. (Bug #54611) * The setting for `BuildIndexThreads' was ignored by *Note `ndbmtd': mysql-cluster-programs-ndbmtd, which made it impossible to use more than 4 cores for rebuilding indexes. (Bug #54521) * When adding multiple new node groups to a MySQL Cluster, it was necessary for each new node group to add only the nodes to be assigned to the new node group, create that node group using `CREATE NODEGROUP', then repeat this process for each new node group to be added to the cluster. The fix for this issue makes it possible to add all of the new nodes at one time, and then issue several `CREATE NODEGROUP' commands in succession. (Bug #54497) * When performing an online alter table where 2 or more SQL nodes connected to the cluster were generating binary logs, an incorrect message could be sent from the data nodes, causing *Note `mysqld': mysqld. processes to crash. This problem was often difficult to detect, because restarting SQL node or data node processes could clear the error, and because the crash in *Note `mysqld': mysqld. did not occur until several minutes after the erroneous message was sent and received. (Bug #54168) * A table having the maximum number of attributes permitted could not be backed up using the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client. *Note*: The maximum number of attributes supported per table is not the same for all MySQL Cluster releases. See *Note mysql-cluster-limitations-database-objects::, to determine the maximum that applies in the release which you are using. (Bug #54155) * During initial node restarts, initialization of the REDO log was always performed 1 node at a time, during start phase 4. Now this is done during start phase 2, so that the initialization can be performed in parallel, thus decreasing the time required for initial restarts involving multiple nodes. (Bug #50062) * The presence of duplicate `[tcp]' sections in the `config.ini' file caused the management server to crash. Now in such cases, *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. fails gracefully with an appropriate error message. (Bug #49400) * The two MySQL Server options, `--ndb-wait-connected' and `--ndb-wait-setup', did not set the corresponding system variables. (Bug #48402) * *Cluster Replication*: An error in an `NDB' internal byte mask value could lead to corruption of replicated *Note `BIT': numeric-types. column values. (Bug #54005) See also Bug #53622. * *Cluster API*: When using the NDB API, it was possible to rename a table with the same name as that of an existing table. *Note*: This issue did not affect table renames executed using SQL on MySQL servers acting as MySQL Cluster API nodes. (Bug #54651) * *Cluster API*: An excessive number of client connections, such that more than 1024 file descriptors, sockets, or both were open, caused NDB API applications to crash. (Bug #34303)  File: manual.info, Node: mysql-cluster-news-5-1-44-ndb-7-0-15b, Next: mysql-cluster-news-5-1-44-ndb-7-0-15a, Prev: mysql-cluster-news-5-1-47-ndb-7-0-16, Up: mysql-cluster-news-7-0 17.7.3.14 Changes in MySQL Cluster NDB 7.0.15b (5.1.44-ndb-7.0.15b) (18 June 2010) .................................................................................. This release replaces MySQL Cluster NDB 7.0.15, fixing a critical issue in that version that was discovered shortly after its release (Bug#54242), as well as MySQL Cluster NDB 7.0.15a, which was not actually released due to Bug#54516 being found during testing. Users of MySQL Cluster NDB 7.0.14 or MySQL Cluster NDB 7.0.15 should upgrade to the 7.0.15b release as soon as possible. Obtaining MySQL Cluster NDB 7.0.15b The latest MySQL Cluster NDB 7.0 binaries for supported platforms can be obtained from `http://dev.mysql.com/downloads/cluster/'. Source code for the latest MySQL Cluster NDB 7.0 release can be obtained from the same location. This release also incorporates all bugfixes and changes made in previous MySQL Cluster releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.44 (see *Note news-5-1-44::). *Bugs fixed:* * *Cluster API*: The value of an internal constant used in the implementation of the `NdbOperation' and `NdbScanOperation' classes caused MySQL Cluster NDB 7.0 NDB API applications compiled against MySQL Cluster NDB 7.0.14 or earlier to fail when run with MySQL Cluster 7.0.15, and MySQL Cluster NDB 7.1 NDB API applications compiled against MySQL Cluster NDB 7.1.3 or earlier to break when used with MySQL Cluster 7.1.4. (Bug #54516)  File: manual.info, Node: mysql-cluster-news-5-1-44-ndb-7-0-15a, Next: mysql-cluster-news-5-1-44-ndb-7-0-15, Prev: mysql-cluster-news-5-1-44-ndb-7-0-15b, Up: mysql-cluster-news-7-0 17.7.3.15 Changes in MySQL Cluster NDB 7.0.15a (5.1.44-ndb-7.0.15a) (Not released) .................................................................................. This was intended as a replacement release for MySQL Cluster NDB 7.0.15, fixing a critical issue in that version that was discovered shortly after its release (Bug#54242); however, MySQL Cluster NDB 7.0.15a was not actually released due to Bug#54516 being found during testing. Users of MySQL Cluster NDB 7.0.14 or MySQL Cluster NDB 7.0.15 should upgrade to the 7.0.15b release as soon as possible. The latest MySQL Cluster NDB 7.0 binaries for supported platforms can be obtained from `http://dev.mysql.com/downloads/cluster/'. Source code for the latest MySQL Cluster NDB 7.0 release can be obtained from the same location. This release also incorporates all bugfixes and changes made in previous MySQL Cluster releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.44 (see *Note news-5-1-44::). *Bugs fixed:* * When using *Note `mysqldump': mysqldump. to back up and restore schema information while using *Note `ndb_restore': mysql-cluster-programs-ndb-restore. for restoring only the data, restoring to MySQL Cluster NDB 7.1.4 from an older version failed on tables having columns with default values. This was because versions of MySQL Cluster prior to MySQL Cluster NDB 7.1.4 did not have native support for default values. In addition, the MySQL Server supports *Note `TIMESTAMP': datetime. columns having dynamic default values, such as `DEFAULT CURRENT_TIMESTAMP'; however, the current implementation of `NDB'-native default values permits only a constant default value. To fix this issue, the manner in which `NDB' treats *Note `TIMESTAMP': datetime. columns is reverted to its pre-NDB-7.1.4 behavior (obtaining the default value from *Note `mysqld': mysqld. rather than `NDBCLUSTER') except where a *Note `TIMESTAMP': datetime. column uses a constant default, as in the case of a column declared as `TIMESTAMP DEFAULT 0' or `TIMESTAMP DEFAULT 20100607174832'. (Bug #54242)  File: manual.info, Node: mysql-cluster-news-5-1-44-ndb-7-0-15, Next: mysql-cluster-news-5-1-44-ndb-7-0-14, Prev: mysql-cluster-news-5-1-44-ndb-7-0-15a, Up: mysql-cluster-news-7-0 17.7.3.16 Changes in MySQL Cluster NDB 7.0.15 (5.1.44-ndb-7.0.15) (31 May 2010) ............................................................................... This release incorporates new features in the *Note `NDBCLUSTER': mysql-cluster. storage engine and fixes recently discovered bugs in MySQL Cluster NDB 7.0.14. Obtaining MySQL Cluster NDB 7.0.15 The latest MySQL Cluster NDB 7.0 binaries for supported platforms can be obtained from `http://dev.mysql.com/downloads/cluster/'. Source code for the latest MySQL Cluster NDB 7.0 release can be obtained from the same location. You can also access the MySQL Cluster NDB 7.0 development source tree at `https://code.launchpad.net/~mysql/mysql-server/mysql-cluster-7.0'. This release also incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.1, 6.2, 6.3, and 7.0 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.44 (see *Note news-5-1-44::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * *Important Change*: The maximum number of attributes (columns plus indexes) per table has increased to 512. * A `--wait-nodes' option has been added for *Note `ndb_waiter': mysql-cluster-programs-ndb-waiter. When this option is used, the program waits only for the nodes having the listed IDs to reach the desired state. For more information, see *Note mysql-cluster-programs-ndb-waiter::. (Bug #52323) * As part of this change, new methods relating to default values have been added to the `Column' and `Table' classes in the NDB API. For more information, see `Column::getDefaultValue()' (http://dev.mysql.com/doc/ndbapi/en/ndb-column-methods.html#ndb-column-getdefaultvalue), `Column::setDefaultValue()' (http://dev.mysql.com/doc/ndbapi/en/ndb-column-methods.html#ndb-column-setdefaultvalue), and `Table::hasDefaultValues()' (http://dev.mysql.com/doc/ndbapi/en/ndb-table-methods.html#ndb-table-hasdefaultvalues). (Bug #30529) * Added the MySQL Cluster management server option `--config-cache', which makes it possible to enable and disable configuration caching. This option is turned on by default; to disable configuration caching, start *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. with `--config-cache=0', or with `--skip-config-cache'. See *Note mysql-cluster-programs-ndb-mgmd::, for more information. * Added the `--skip-unknown-objects' option for *Note `ndb_restore': mysql-cluster-programs-ndb-restore. This option causes *Note `ndb_restore': mysql-cluster-programs-ndb-restore. to ignore any schema objects which it does not recognize. Currently, this is useful chiefly for restoring native backups made from a cluster running MySQL Cluster NDB 7.0 to a cluster running MySQL Cluster NDB 6.3. *Bugs fixed:* * After creating *Note `NDB': mysql-cluster. tables until creation of a table failed due to *Note `NDB': mysql-cluster. error 905 `Out of attribute records (increase MaxNoOfAttributes)', then increasing `MaxNoOfAttributes' and restarting all management node and data node processes, attempting to drop and re-create one of the tables failed with the error `Out of table records...', even when sufficient table records were available. (Bug #53944) See also Bug #52055. * Creating a Disk Data table, dropping it, then creating an in-memory table and performing a restart, could cause data node processes to fail with errors in the `DBTUP' kernel block if the new table's internal ID was the same as that of the old Disk Data table. This could occur because undo log handling during the restart did not check that the table having this ID was now in-memory only. (Bug #53935) * A table created while `ndb_table_no_logging' was enabled was not always stored to disk, which could lead to a data node crash with `Error opening DIH schema files for table'. (Bug #53934) * An internal buffer allocator used by *Note `NDB': mysql-cluster. has the form `alloc(WANTED, MINIMUM)' and attempts to allocate WANTED pages, but is permitted to allocate a smaller number of pages, between WANTED and MINIMUM. However, this allocator could sometimes allocate fewer than MINIMUM pages, causing problems with multi-threaded building of ordered indexes. (Bug #53580) * When compiled with support for `epoll' but this functionality is not available at runtime, MySQL Cluster tries to fall back to use the `select()' function in its place. However, an extra `ndbout_c()' call in the transporter registry code caused *Note `ndbd': mysql-cluster-programs-ndbd. to fail instead. (Bug #53482) * The value set for the *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. option `--ndb-nodeid' was not verified prior to use as being within the permitted range (1 to 255, inclusive), leading to a crash of the management server. (Bug #53412) * `NDB' truncated a column declared as *Note `DECIMAL(65,0)': numeric-types. to a length of 64. Now such a column is accepted and handled correctly. In cases where the maximum length (65) is exceeded, `NDB' now raises an error instead of truncating. (Bug #53352) * When an `NDB' log handler failed, the memory allocated to it was freed twice. (Bug #53200) * Setting `DataMemory' higher than 4G on 32-bit platforms caused *Note `ndbd': mysql-cluster-programs-ndbd. to crash, instead of failing gracefully with an error. (Bug #52536, Bug #50928) * When the `LogDestination' parameter was set using with a relative path, the management server failed to store its value unless started with `--initial' or `--reload'. (Bug #52268) * When creating an index, *Note `NDB': mysql-cluster. failed to check whether the internal ID allocated to the index was within the permissible range, leading to an assertion. This issue could manifest itself as a data node failure with `NDB' error 707 (`No more table metadata records (increase MaxNoOfTables)'), when creating tables in rapid succession (for example, by a script, or when importing from *Note `mysqldump': mysqldump.), even with a relatively high value for `MaxNoOfTables' and a relatively low number of tables. (Bug #52055) * *Note `ndb_restore': mysql-cluster-programs-ndb-restore. did not raise any errors if hashmap creation failed during execution. (Bug #51434) * Specifying the node ID as part of the `--ndb-connectstring' option to *Note `mysqld': mysqld. was not handled correctly. The fix for this issue includes the following changes: * Multiple occurrences of any of the *Note `mysqld': mysqld. options `--ndb-connectstring', `--ndb-mgmd-host', and `--ndb-nodeid' are now handled in the same way as with other MySQL server options, in that the value set in the last occurrence of the option is the value that is used by *Note `mysqld': mysqld. Now, if `--ndb-nodeid' is used, its value overrides that of any `nodeid' setting used in `--ndb-connectstring'. For example, starting *Note `mysqld': mysqld. with `--ndb-connectstring=nodeid=1,10.100.1.100 --ndb-nodeid=3' now produces the same result as starting it with `--ndb-connectstring=nodeid=3,10.100.1.100'. * The 1024-character limit on the length of the connectstring is removed, and `--ndb-connectstring' is now handled in this regard in the same way as other *Note `mysqld': mysqld. options. * In the NDB API, a new constructor for `Ndb_cluster_connection' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndb-cluster-connection.html#ndb-ndb-cluster-connection) is added which takes as its arguments a connectstring and the node ID to force the API node to use. (Bug #44299) * NDB did not distinguish correctly between table names differing only by lettercase when `lower_case_table_names' was set to 0. (Bug #33158) * `ndb_mgm -e "ALL STATUS"' erroneously reported that data nodes remained in start phase 0 until they had actually started. * *Replication*: A buffer overrun in the handling of *Note `DATE': datetime. column values could cause mysqlbinlog to fail when reading back logs containing certain combinations of DML on a table having a *Note `DATE': datetime. column followed by dropping the table. (Bug #52202) * *Cluster Replication*: Replication failed after a restart of the slave SQL node, due to an error in writing the `master.info' file. (Bug #52859) * *Note `ALTER TABLE': alter-table. did not work correctly where the name of the table, the database, or both contained special characters, causing the MySQL server to crash. (Bug #52225) See also Bug #53409, Bug #14959. * The performance of MySQL applications using non-persistent client connections was adversely affected due to many of these connections being kept waiting for an excessive length of time in cleanup phase while being closed. (Bug #48832) * The MySQL client library mishandled `EINPROGRESS' errors for connections in nonblocking mode. This could lead to replication failures on hosts capable of resolving both IPv4 and IPv6 network addresses, when trying to resolve `localhost'. (Bug #37267) See also Bug #44344.  File: manual.info, Node: mysql-cluster-news-5-1-44-ndb-7-0-14, Next: mysql-cluster-news-5-1-41-ndb-7-0-13, Prev: mysql-cluster-news-5-1-44-ndb-7-0-15, Up: mysql-cluster-news-7-0 17.7.3.17 Changes in MySQL Cluster NDB 7.0.14 (5.1.44-ndb-7.0.14) (31 March 2010) ................................................................................. This release incorporates new features in the *Note `NDBCLUSTER': mysql-cluster. storage engine and fixes recently discovered bugs in MySQL Cluster NDB 7.0.13. Obtaining MySQL Cluster NDB 7.0.14 The latest MySQL Cluster NDB 7.0 binaries for supported platforms can be obtained from `http://dev.mysql.com/downloads/cluster/'. Source code for the latest MySQL Cluster NDB 7.0 release can be obtained from the same location. You can also access the MySQL Cluster NDB 7.0 development source tree at `https://code.launchpad.net/~mysql/mysql-server/mysql-cluster-7.0'. This release also incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.1, 6.2, 6.3, and 7.0 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.44 (see *Note news-5-1-44::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * *Cluster API*: It is now possible to determine, using the *Note `ndb_desc': mysql-cluster-programs-ndb-desc. utility or the NDB API, which data nodes contain replicas of which partitions. For *Note `ndb_desc': mysql-cluster-programs-ndb-desc, a new `--extra-node-info' option is added to cause this information to be included in its output. A new method `Table::getFragmentNodes()' is added to the NDB API for obtaining this information programmatically. (Bug #51184) * Formerly, the `REPORT' and `DUMP' commands returned output to all *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. clients connected to the same MySQL Cluster. Now, these commands return their output only to the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client that actually issued the command. (Bug #40865) * *Cluster Replication*: *Replication*: MySQL Cluster Replication now supports attribute promotion and demotion for row-based replication between columns of different but similar types on the master and the slave. For example, it is possible to promote an *Note `INT': numeric-types. column on the master to a *Note `BIGINT': numeric-types. column on the slave, and to demote a *Note `TEXT': blob. column to a *Note `VARCHAR': char. column. The implementation of type demotion distinguishes between lossy and non-lossy type conversions, and their use on the slave can be controlled by setting the `slave_type_conversions' global server system variable. For more information about attribute promotion and demotion for row-based replication in MySQL Cluster, see *Note replication-features-attribute-promotion::. (Bug #47163, Bug #46584) *Bugs fixed:* * *Cluster API*: *Incompatible Change*: The default behavior of the NDB API Event API has changed as follows: Previously, when creating an `Event', DDL operations (alter and drop operations on tables) were automatically reported on any event operation that used this event, but as a result of this change, this is no longer the case. Instead, you must now invoke the event's `setReport()' method, with the new `EventReport' value `ER_DDL', to get this behavior. For existing NDB API applications where you wish to retain the old behavior, you must update the code as indicated previously, then recompile, following an upgrade. Otherwise, DDL operations are no longer reported after upgrading `libndbnclient'. For more information, see The `Event::EventReport' Type (http://dev.mysql.com/doc/ndbapi/en/ndb-event-types.html#ndb-event-eventreport), and `Event::setReport()' (http://dev.mysql.com/doc/ndbapi/en/ndb-event-methods.html#ndb-event-setreport). (Bug #53308) * If a node or cluster failure occurred while *Note `mysqld': mysqld. was scanning the `ndb.ndb_schema' table (which it does when attempting to connect to the cluster), insufficient error handling could lead to a crash by *Note `mysqld': mysqld. in certain cases. This could happen in a MySQL Cluster with a great many tables, when trying to restart data nodes while one or more *Note `mysqld': mysqld. processes were restarting. (Bug #52325) * In MySQL Cluster NDB 7.0 and later, DDL operations are performed within schema transactions; the NDB kernel code for starting a schema transaction checks that all data nodes are at the same version before permitting a schema transaction to start. However, when a version mismatch was detected, the client was not actually informed of this problem, which caused the client to hang. (Bug #52228) * After running a mixed series of node and system restarts, a system restart could hang or fail altogether. This was caused by setting the value of the newest completed global checkpoint too low for a data node performing a node restart, which led to the node reporting incorrect GCI intervals for its first local checkpoint. (Bug #52217) * When performing a complex mix of node restarts and system restarts, the node that was elected as master sometimes required optimized node recovery due to missing `REDO' information. When this happened, the node crashed with `Failure to recreate object ... during restart, error 721' (because the `DBDICT' restart code was run twice). Now when this occurs, node takeover is executed immediately, rather than being made to wait until the remaining data nodes have started. (Bug #52135) See also Bug #48436. * The internal variable `ndb_new_handler', which is no longer used, has been removed. (Bug #51858) * `ha_ndbcluster.cc' was not compiled with the same `SAFEMALLOC' and `SAFE_MUTEX' flags as the MySQL Server. (Bug #51857) * When debug compiling MySQL Cluster on Windows, the mysys library was not compiled with -DSAFEMALLOC and -DSAFE_MUTEX, due to the fact that my_socket.c was misnamed as my_socket.cc. (Bug #51856) * The redo log protects itself from being filled up by periodically checking how much space remains free. If insufficient redo log space is available, it sets the state `TAIL_PROBLEM' which results in transactions being aborted with error code 410 (`out of redo log'). However, this state was not set following a node restart, which meant that if a data node had insufficient redo log space following a node restart, it could crash a short time later with `Fatal error due to end of REDO log'. Now, this space is checked during node restarts. (Bug #51723) * Restoring a MySQL Cluster backup between platforms having different endianness failed when also restoring metadata and the backup contained a hashmap not already present in the database being restored to. This issue was discovered when trying to restore a backup made on Solaris/SPARC to a MySQL Cluster running on Solaris/x86, but could conceivably occur in other cases where the endianness of the platform on which the backup was taken differed from that of the platform being restored to. (Bug #51432) * The output of the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client `REPORT BACKUPSTATUS' command could sometimes contain errors due to uninitialized data. (Bug #51316) * A `GROUP BY' query against *Note `NDB': mysql-cluster. tables sometimes did not use any indexes unless the query included a `FORCE INDEX' option. With this fix, indexes are used by such queries (where otherwise possible) even when `FORCE INDEX' is not specified. (Bug #50736) * The following issues were fixed in the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client `REPORT MEMORYUSAGE' command: * The client sometimes inserted extra `ndb_mgm>' prompts within the output. * For data nodes running *Note `ndbmtd': mysql-cluster-programs-ndbmtd, `IndexMemory' was reported before `DataMemory'. * In addition, for data nodes running *Note `ndbmtd': mysql-cluster-programs-ndbmtd, there were multiple `IndexMemory' entries listed in the output. (Bug #50196) * Issuing a command in the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client after it had lost its connection to the management server could cause the client to crash. (Bug #49219) * The *Note `mysql': mysql. client `system' command did not work properly. This issue was only known to affect the version of the *Note `mysql': mysql. client that was included with MySQL Cluster NDB 7.0 and MySQL Cluster NDB 7.1 releases. (Bug #48574) * The internal `ErrorReporter::formatMessage()' method could in some cases cause a buffer overflow. (Bug #47120) * Information about several management client commands was missing from (that is, truncated in) the output of the `HELP' command. (Bug #46114) * The *Note `ndb_print_backup_file': mysql-cluster-programs-ndb-print-backup-file. utility failed to function, due to a previous internal change in the NDB code. (Bug #41512, Bug #48673) * When the `MemReportFrequency' configuration parameter was set in `config.ini', the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client `REPORT MEMORYUSAGE' command printed its output multiple times. (Bug #37632) * *Note `ndb_mgm -e "... REPORT ..."': mysql-cluster-programs-ndb-mgm. did not write any output to `stdout'. The fix for this issue also prevents the cluster log from being flooded with `INFO' messages when `DataMemory' usage reaches 100%, and insures that when the usage is decreased, an appropriate message is written to the cluster log. (Bug #31542, Bug #44183, Bug #49782) * *InnoDB Storage Engine*: *Replication*: Column length information generated by *Note `InnoDB': innodb-storage-engine. did not match that generated by *Note `MyISAM': myisam-storage-engine, which caused invalid metadata to be written to the binary log when trying to replicate *Note `BIT': numeric-types. columns. (Bug #49618) * *Replication*: Metadata for `GEOMETRY' fields was not properly stored by the slave in its definitions of tables. (Bug #49836) See also Bug #48776. * *Disk Data*: Inserts of blob column values into a MySQL Cluster Disk Data table that exhausted the tablespace resulted in misleading `no such tuple' error messages rather than the expected error `tablespace full'. This issue appeared similar to Bug#48113, but had a different underlying cause. (Bug #52201) * *Disk Data*: The error message returned after atttempting to execute *Note `ALTER LOGFILE GROUP': alter-logfile-group. on an nonexistent logfile group did not indicate the reason for the failure. (Bug #51111) * *Disk Data*: DDL operations on Disk Data tables having a relatively small `UNDO_BUFFER_SIZE' could fail unexpectedly. * *Cluster Replication*: The `--ndb-log-empty-epochs' option did not work correctly. (Bug #49559) * *Cluster Replication*: When *Note `mysqld': mysqld. was started with `--binlog-do-db' or `--binlog-ignore-db', no `LOST_EVENTS' incident was written to the binary log. (Bug #47096) * *Cluster API*: When reading blob data with lock mode `LM_SimpleRead', the lock was not upgraded as expected. (Bug #51034) * *Cluster API*: A number of issues were corrected in the NDB API coding examples found in the `storage/ndb/ndbapi-examples' directory in the MySQL Cluster source tree. These included possible endless recursion in `ndbapi_scan.cpp' as well as problems running some of the examples on systems using Windows or Mac OS X due to the lettercase used for some table names. (Bug #30552, Bug #30737) * On some Unix/Linux platforms, an error during build from source could be produced, referring to a missing `LT_INIT' program. This is due to versions of `libtool' 2.1 and earlier. (Bug #51009) * 1) In rare cases, if a thread was interrupted during a *Note `FLUSH PRIVILEGES': flush. operation, a debug assertion occurred later due to improper diagnostics area setup. 2) A *Note `KILL': kill. operation could cause a console error message referring to a diagnostic area state without first ensuring that the state existed. (Bug #33982)  File: manual.info, Node: mysql-cluster-news-5-1-41-ndb-7-0-13, Next: mysql-cluster-news-5-1-41-ndb-7-0-12b, Prev: mysql-cluster-news-5-1-44-ndb-7-0-14, Up: mysql-cluster-news-7-0 17.7.3.18 Changes in MySQL Cluster NDB 7.0.13 (5.1.41-ndb-7.0.13) (04 March 2010) ................................................................................. This release incorporates new features in the *Note `NDBCLUSTER': mysql-cluster. storage engine and fixes recently discovered bugs in MySQL Cluster NDB 7.0.12. This release also incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.1, 6.2, 6.3, and 7.0 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.41 (see *Note news-5-1-41::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * A new configuration parameter `HeartbeatThreadPriority' makes it possible to select between a first-in, first-out or round-round scheduling policy for management node and API node heartbeat threads, as well as to set the priority of these threads. See *Note mysql-cluster-mgm-definition::, or *Note mysql-cluster-api-definition::, for more information. (Bug #49617) * Start phases are now written to the data node logs. (Bug #49158) * *Disk Data*: The *Note `ndb_desc': mysql-cluster-programs-ndb-desc. utility can now show the extent space and free extent space for subordinate *Note `BLOB': blob. and *Note `TEXT': blob. columns (stored in hidden `BLOB' tables by NDB). A `--blob-info' option has been added for this program that causes *Note `ndb_desc': mysql-cluster-programs-ndb-desc. to generate a report for each subordinate `BLOB' table. For more information, see *Note mysql-cluster-programs-ndb-desc::. (Bug #50599) *Bugs fixed:* * When performing a system restart of a MySQL Cluster where multi-threaded data nodes were in use, there was a slight risk that the restart would hang due to incorrect serialization of signals passed between LQH instances and proxies; some signals were sent using a proxy, and others directly, which meant that the order in which they were sent and received could not be guaranteed. If signals arrived in the wrong order, this could cause one or more data nodes to hang. Now all signals that need to be sent and received in the same order are sent using the same path. (Bug #51645) * When one or more data nodes read their LCPs and applied undo logs significantly faster than others, this could lead to a race condition causing system restarts of data nodes to hang. This could most often occur when using both *Note `ndbd': mysql-cluster-programs-ndbd. and *Note `ndbmtd': mysql-cluster-programs-ndbmtd. processes for the data nodes. (Bug #51644) * When deciding how to divide the REDO log, the `DBDIH' kernel block saved more than was needed to restore the previous local checkpoint, which could cause REDO log space to be exhausted prematurely (`NDB' error 410). (Bug #51547) * DML operations can fail with `NDB' error 1220 (`REDO log files overloaded...') if the opening and closing of REDO log files takes too much time. If this occurred as a GCI marker was being written in the REDO log while REDO log file 0 was being opened or closed, the error could persist until a GCP stop was encountered. This issue could be triggered when there was insufficient REDO log space (for example, with configuration parameter settings `NoOfFragmentLogFiles = 6' and `FragmentLogFileSize = 6M') with a load including a very high number of updates. (Bug #51512) See also Bug #20904. * A side effect of the *Note `ndb_restore': mysql-cluster-programs-ndb-restore. `--disable-indexes' and `--rebuild-indexes' options is to change the schema versions of indexes. When a *Note `mysqld': mysqld. later tried to drop a table that had been restored from backup using one or both of these options, the server failed to detect these changed indexes. This caused the table to be dropped, but the indexes to be left behind, leading to problems with subsequent backup and restore operations. (Bug #51374) * *Note `ndb_restore': mysql-cluster-programs-ndb-restore. crashed while trying to restore a corrupted backup, due to missing error handling. (Bug #51223) * The *Note `ndb_restore': mysql-cluster-programs-ndb-restore. message `Successfully created index `PRIMARY`...' was directed to `stderr' instead of `stdout'. (Bug #51037) * When using `NoOfReplicas' equal to 1 or 2, if data nodes from one node group were restarted 256 times and applications were running traffic such that it would encounter *Note `NDB': mysql-cluster. error 1204 (`Temporary failure, distribution changed'), the live node in the node group would crash, causing the cluster to crash as well. The crash occurred only when the error was encountered on the 256th restart; having the error on any previous or subsequent restart did not cause any problems. (Bug #50930) * Replication of a MySQL Cluster using multi-threaded data nodes could fail with forced shutdown of some data nodes due to the fact that *Note `ndbmtd': mysql-cluster-programs-ndbmtd. exhausted `LongMessageBuffer' much more quickly than *Note `ndbd': mysql-cluster-programs-ndbd. After this fix, passing of replication data between the `DBTUP' and `SUMA' NDB kernel blocks is done using `DataMemory' rather than `LongMessageBuffer'. Until you can upgrade, you may be able to work around this issue by increasing the `LongMessageBuffer' setting; doubling the default should be sufficient in most cases. (Bug #46914) * A *Note `SELECT': select. requiring a sort could fail with the error `Can't find record in 'TABLE'' when run concurrently with a *Note `DELETE': delete. from the same table. (Bug #45687) * *Cluster API*: An issue internal to *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. could cause problems when trying to start a large number of data nodes at the same time. (Bug #51273) See also Bug #51310.  File: manual.info, Node: mysql-cluster-news-5-1-41-ndb-7-0-12b, Next: mysql-cluster-news-5-1-41-ndb-7-0-12a, Prev: mysql-cluster-news-5-1-41-ndb-7-0-13, Up: mysql-cluster-news-7-0 17.7.3.19 Changes in MySQL Cluster NDB 7.0.12b (5.1.41-ndb-7.0.12b) (18 February 2010) ...................................................................................... This is a replacement release for MySQL Cluster NDB 7.0.12a, fixing a critical issue in that version that was discovered shortly after its release (Bug#51256). MySQL Cluster NDB 7.0.12b is identical in all other respects to MySQL Cluster NDB 7.0.12 and MySQL Cluster NDB 7.0.12a. Users of MySQL Cluster NDB 7.0.12 or MySQL Cluster NDB 7.0.12a (only) should upgrade to the 7.0.12b release as soon as possible. This is a testing release only, for the purpose of testing the fix for Bug#49190 (now also incorporating the fix for Bug#51027 and Bug#51256). This release is otherwise identical to MySQL Cluster NDB 7.0.11b; users of MySQL Cluster NDB 7.0.11 or MySQL Cluster NDB 7.0.11a who are not interested in testing this change should upgrade to MySQL Cluster NDB 7.0.11b (if they have not done so already), then wait until MySQL Cluster NDB 7.0.13 becomes available. Obtaining MySQL Cluster NDB 7.0.12a This is a source-only release. You can obtain the GPL source code for MySQL Cluster NDB 7.0.12a from `ftp://ftp.mysql.com/pub/mysql/download/cluster_telco/mysql-5.1.41-ndb-7.0.12a/'. You can also access the MySQL Cluster NDB 7.0 development source tree at `https://code.launchpad.net/~mysql/mysql-server/mysql-cluster-7.0'. This release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 7.0 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.41 (see *Note news-5-1-41::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Bugs fixed:* * An initial restart of a data node configured with a large amount of memory could fail with a `Pointer too large' error. (Bug #51027) This regression was introduced by Bug #47818.  File: manual.info, Node: mysql-cluster-news-5-1-41-ndb-7-0-12a, Next: mysql-cluster-news-5-1-41-ndb-7-0-12, Prev: mysql-cluster-news-5-1-41-ndb-7-0-12b, Up: mysql-cluster-news-7-0 17.7.3.20 Changes in MySQL Cluster NDB 7.0.12a (5.1.41-ndb-7.0.12a) (15 February 2010) ...................................................................................... *Note*: MySQL Cluster NDB 7.0.12a was withdrawn shortly after release, due to Bug#51256. Users of the original 7.0.12 release should upgrade to MySQL Cluster NDB 7.0.12b, which fixes this issue (and others). Users of MySQL Cluster NDB 7.0.11 or MySQL Cluster NDB 7.0.11a should upgrade to MySQL Cluster NDB 7.0.11b, if they have not done so already. This is a replacement release for MySQL Cluster NDB 7.0.12, fixing a critical issue in that version that was discovered shortly after its release (Bug#51027). MySQL Cluster NDB 7.0.12a is identical in all other respects to MySQL Cluster NDB 7.0.12. Users of MySQL Cluster NDB 7.0.12 (only) should upgrade to the 7.0.12a release as soon as possible. This is a testing release only, for the purpose of testing the fix for Bug#49190 (now also incorporating the fix for Bug#51027). This release is otherwise identical to MySQL Cluster NDB 7.0.11b; users of MySQL Cluster NDB 7.0.11 or MySQL Cluster NDB 7.0.11a who are not interested in testing this change should upgrade to MySQL Cluster NDB 7.0.11b (if they have not done so already), then wait until MySQL Cluster NDB 7.0.13 becomes available. This release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 7.0 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.41 (see *Note news-5-1-41::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Bugs fixed:* * An initial restart of a data node configured with a large amount of memory could fail with a `Pointer too large' error. (Bug #51027) This regression was introduced by Bug #47818.  File: manual.info, Node: mysql-cluster-news-5-1-41-ndb-7-0-12, Next: mysql-cluster-news-5-1-41-ndb-7-0-11b, Prev: mysql-cluster-news-5-1-41-ndb-7-0-12a, Up: mysql-cluster-news-7-0 17.7.3.21 Changes in MySQL Cluster NDB 7.0.12 (5.1.41-ndb-7.0.12) (03 February 2010) .................................................................................... *Note*: MySQL Cluster NDB 7.0.12 was withdrawn shortly after release, due to Bug#51027. Users of the original 7.0.12 release should upgrade to MySQL Cluster NDB 7.0.12b, which fixes this issue (and others). Users of MySQL Cluster NDB 7.0.11 or MySQL Cluster NDB 7.0.11a should upgrade to MySQL Cluster NDB 7.0.11b, if they have not done so already. This is a testing release only, for the purpose of testing the fix for Bug#49190. This release is otherwise identical to MySQL Cluster NDB 7.0.11b; users of MySQL Cluster NDB 7.0.11 or MySQL Cluster NDB 7.0.11a who are not interested in testing this change should upgrade to MySQL Cluster NDB 7.0.11b (if they have not done so already), then wait until MySQL Cluster NDB 7.0.13 becomes available. This release also incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.1, 6.2, 6.3, and 7.0 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.41 (see *Note news-5-1-41::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * Numeric codes used in management server status update messages in the cluster logs have been replaced with text descriptions. (Bug #49627) See also Bug #44248. *Bugs fixed:* * *Note `ndbmtd': mysql-cluster-programs-ndbmtd. started on a single-core machine could sometimes fail with a `Job Buffer Full' error when `MaxNoOfExecutionThreads' was set greater than `LockExecuteThreadToCPU'. Now a warning is logged when this occurs. (Bug #50582) * When a primary key lookup on an *Note `NDB': mysql-cluster. table containing one or more *Note `BLOB': blob. columns was executed in a transaction, a shared lock on any blob tables used by the *Note `NDB': mysql-cluster. table was held for the duration of the transaction. (This did not occur for indexed or non-indexed `WHERE' conditions.) Now in such cases, the lock is released after all *Note `BLOB': blob. data has been read. (Bug #49190)  File: manual.info, Node: mysql-cluster-news-5-1-41-ndb-7-0-11b, Next: mysql-cluster-news-5-1-41-ndb-7-0-11a, Prev: mysql-cluster-news-5-1-41-ndb-7-0-12, Up: mysql-cluster-news-7-0 17.7.3.22 Changes in MySQL Cluster NDB 7.0.11b (5.1.41-ndb-7.0.11b) (18 February 2010) ...................................................................................... This is a replacement release for MySQL Cluster NDB 7.0.11a, fixing a critical issue in that version that was discovered shortly after its release (Bug#51256). MySQL Cluster NDB 7.0.11b is identical in all other respects to MySQL Cluster NDB 7.0.11a. Users of MySQL Cluster NDB 7.0.11 or MySQL Cluster NDB 7.0.11a should upgrade to the 7.0.11b release as soon as possible. Users of previous MySQL Cluster NDB 7.0 releases should bypass the 7.0.11 and 7.0.11a releases, and upgrade to 7.0.11b instead. Obtaining MySQL Cluster NDB 7.0.11b This is a source-only release. You can obtain the GPL source code for MySQL Cluster NDB 7.0.11b from `ftp://ftp.mysql.com/pub/mysql/download/cluster_telco/mysql-5.1.41-ndb-7.0.11b/'. You can also access the MySQL Cluster NDB 7.0 development source tree at `https://code.launchpad.net/~mysql/mysql-server/mysql-cluster-7.0'. This release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 7.0 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.41 (see *Note news-5-1-41::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Bugs fixed:* * Setting `IndexMemory' greater than 2GB could cause data nodes to crash while starting. (Bug #51256)  File: manual.info, Node: mysql-cluster-news-5-1-41-ndb-7-0-11a, Next: mysql-cluster-news-5-1-41-ndb-7-0-11, Prev: mysql-cluster-news-5-1-41-ndb-7-0-11b, Up: mysql-cluster-news-7-0 17.7.3.23 Changes in MySQL Cluster NDB 7.0.11a (5.1.41-ndb-7.0.11a) (15 February 2010) ...................................................................................... This is a replacement release for MySQL Cluster NDB 7.0.11, fixing a critical issue in that version that was discovered shortly after its release (Bug#51027). MySQL Cluster NDB 7.0.11a is identical in all other respects to MySQL Cluster NDB 7.0.11. Users of MySQL Cluster NDB 7.0.11 should upgrade to the 7.0.11a release as soon as possible. Users of previous MySQL Cluster NDB 7.0 releases should bypass the 7.0.11 release and upgrade to 7.0.11a instead. Obtaining MySQL Cluster NDB 7.0.11a This is a source-only release. You can obtain the GPL source code for MySQL Cluster NDB 7.0.11a from `ftp://ftp.mysql.com/pub/mysql/download/cluster_telco/mysql-5.1.41-ndb-7.0.11a/'. You can also access the MySQL Cluster NDB 7.0 development source tree at `https://code.launchpad.net/~mysql/mysql-server/mysql-cluster-7.0'. This release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 7.0 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.41 (see *Note news-5-1-41::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Bugs fixed:* * An initial restart of a data node configured with a large amount of memory could fail with a `Pointer too large' error. (Bug #51027) This regression was introduced by Bug #47818.  File: manual.info, Node: mysql-cluster-news-5-1-41-ndb-7-0-11, Next: mysql-cluster-news-5-1-39-ndb-7-0-10, Prev: mysql-cluster-news-5-1-41-ndb-7-0-11a, Up: mysql-cluster-news-7-0 17.7.3.24 Changes in MySQL Cluster NDB 7.0.11 (5.1.41-ndb-7.0.11) (02 February 2010) .................................................................................... *Note*: MySQL Cluster NDB 7.0.11 was withdrawn shortly after release, due to Bug#51027. Users should upgrade to MySQL Cluster NDB 7.0.11a, which fixes this issue. This release incorporates new features in the *Note `NDBCLUSTER': mysql-cluster. storage engine and fixes recently discovered bugs in MySQL Cluster NDB 7.0.10. This release also incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.1, 6.2, 6.3, and 7.0 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.39 (see *Note news-5-1-41::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * *Important Change*: The maximum permitted value of the `ndb_autoincrement_prefetch_sz' system variable has been increased from 256 to 65536. (Bug #50621) * Added multi-threaded ordered index building capability during system restarts or node restarts, controlled by the `BuildIndexThreads' data node configuration parameter (also introduced in this release). * *Cluster Replication*: Due to the fact that no timestamp is available for delete operations, a delete using `NDB$MAX()' is actually processed as `NDB$OLD'. However, because this is not optimal for some use cases, `NDB$MAX_DELETE_WIN()' is added as a conflict resolution function; if the `timestamp' column value for a given row adding or updating an existing row coming from the master is higher than that on the slave, it is applied (as with `NDB$MAX()'); however, delete operations are treated as always having the higher value. See *Note mysql-cluster-replication-ndb-max-delete-win::, for more information. (Bug #50650) * *Cluster Replication*: In circular replication, it was sometimes possible for an event to propagate such that it would be reapplied on all servers. This could occur when the originating server was removed from the replication circle and so could no longer act as the terminator of its own events, as normally happens in circular replication. To prevent this from occurring, a new `IGNORE_SERVER_IDS' option is introduced for the `CHANGE MASTER TO' statement. This option takes a list of replication server IDs; events having a server ID which appears in this list are ignored and not applied. For more information, see *Note change-master-to::. In conjunction with the introduction of `IGNORE_SERVER_IDS', *Note `SHOW SLAVE STATUS': show-slave-status. has two new fields. `Replicate_Ignore_Server_Ids' displays information about ignored servers. `Master_Server_Id' displays the `server_id' value from the master. (Bug #47037) See also Bug #25998, Bug #27808. *Bugs fixed:* * Initial start of partitioned nodes did not work correctly. This issue was observed in MySQL Cluster NDB 7.0 only. (Bug #50661) * The `CREATE NODEGROUP' client command in *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. could sometimes cause the forced shutdown of a data node. (Bug #50594) * Local query handler information was not reported or written to the cluster log correctly. This issue is thought to have been introduced in MySQL Cluster NDB 7.0.10. (Bug #50467) * Online upgrades from MySQL Cluster NDB 7.0.9b to MySQL Cluster NDB 7.0.10 did not work correctly. Current MySQL Cluster NDB 7.0 users should upgrade directly to MySQL Cluster NDB 7.0.11 or later. This issue is not known to have affected MySQL Cluster NDB 6.3, and it should be possible to upgrade from MySQL Cluster NDB 6.3 to MySQL Cluster NDB 7.0.10 without problems. See *Note mysql-cluster-upgrade-downgrade-compatibility-6.x::, for more information. (Bug #50433) * Dropping unique indexes in parallel while they were in use could cause node and cluster failures. (Bug #50118) * When attempting to join a running cluster whose management server had been started with the `--nowait-nodes' option and having SQL nodes with dynamically allocated node IDs, a second management server failed with spurious `INTERNAL ERROR: Found dynamic ports with value in config...' error messages. (Bug #49807) * When setting the `LockPagesInMainMemory' configuration parameter failed, only the error `Failed to memlock pages...' was returned. Now in such cases the operating system's error code is also returned. (Bug #49724) * If a query on an *Note `NDB': mysql-cluster. table compared a constant string value to a column, and the length of the string was greater than that of the column, condition pushdown did not work correctly. (The string was truncated to fit the column length before being pushed down.) Now in such cases, the condition is no longer pushed down. (Bug #49459) * *Note `ndbmtd': mysql-cluster-programs-ndbmtd. was not built on Windows (`CMake' did not provide a build target for it). (Bug #49325) * Performing intensive inserts and deletes in parallel with a high scan load could a data node crashes due to a failure in the `DBACC' kernel block. This was because checking for when to perform bucket splits or merges considered the first 4 scans only. (Bug #48700) * During Start Phases 1 and 2, the `STATUS' command sometimes (falsely) returned `Not Connected' for data nodes running *Note `ndbmtd': mysql-cluster-programs-ndbmtd. (Bug #47818) * When performing a *Note `DELETE': delete. that included a left join from an *Note `NDB': mysql-cluster. table, only the first matching row was deleted. (Bug #47054) * Under some circumstances, the `DBTC' kernel block could send an excessive number of commit and completion messages which could lead to a the job buffer filling up and node failure. This was especially likely to occur when using *Note `ndbmtd': mysql-cluster-programs-ndbmtd. with a single data node. (Bug #45989) * *Note `mysqld': mysqld. could sometimes crash during a commit while trying to handle NDB Error 4028 `Node failure caused abort of transaction'. (Bug #38577) * When setting `LockPagesInMainMemory', the stated memory was not allocated when the node was started, but rather only when the memory was used by the data node process for other reasons. (Bug #37430) * Trying to insert more rows than would fit into an `NDB' table caused data nodes to crash. Now in such situations, the insert fails gracefully with error 633 `Table fragment hash index has reached maximum possible size'. (Bug #34348) * On Mac OS X or Windows, sending a `SIGHUP' signal to the server or an asynchronous flush (triggered by `flush_time') caused the server to crash. (Bug #47525) * The *Note `ARCHIVE': archive-storage-engine. storage engine lost records during a bulk insert. (Bug #46961) * When using the *Note `ARCHIVE': archive-storage-engine. storage engine, `SHOW TABLE STATUS' displayed incorrect information for `Max_data_length', `Data_length' and `Avg_row_length'. (Bug #29203)  File: manual.info, Node: mysql-cluster-news-5-1-39-ndb-7-0-10, Next: mysql-cluster-news-5-1-39-ndb-7-0-9b, Prev: mysql-cluster-news-5-1-41-ndb-7-0-11, Up: mysql-cluster-news-7-0 17.7.3.25 Changes in MySQL Cluster NDB 7.0.10 (5.1.39-ndb-7.0.10) (15 December 2009) .................................................................................... This release incorporates new features in the *Note `NDBCLUSTER': mysql-cluster. storage engine and fixes recently discovered bugs in MySQL Cluster NDB 7.0.9a. Obtaining MySQL Cluster NDB 7.0.10 The latest MySQL Cluster NDB 7.0 binaries for supported platforms can be obtained from `http://dev.mysql.com/downloads/cluster/'. Source code for the latest MySQL Cluster NDB 7.0 release can be obtained from the same location. You can also access the MySQL Cluster NDB 7.0 development source tree at `https://code.launchpad.net/~mysql/mysql-server/mysql-cluster-7.0'. This release also incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.1, 6.2, 6.3, and 7.0 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.39 (see *Note news-5-1-39::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * Added the *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. `--nowait-nodes' option, which permits a cluster that is configured to use multiple management servers to be started using fewer than the number configured. This is most likely to be useful when a cluster is configured with two management servers and you wish to start the cluster using only one of them. See *Note mysql-cluster-programs-ndb-mgmd::, for more information. (Bug #48669) * This enhanced functionality is supported for upgrades from MySQL Cluster NDB 6.3 when the *Note `NDB': mysql-cluster. engine version is 6.3.29 or later. (Bug #48528, Bug #49163) * The output from *Note `ndb_config': mysql-cluster-programs-ndb-config. `--configinfo' `--xml' now indicates, for each configuration parameter, the following restart type information: * Whether a system restart or a node restart is required when resetting that parameter; * Whether cluster nodes need to be restarted using the `--initial' option when resetting the parameter. (Bug #47366) *Bugs fixed:* * Node takeover during a system restart occurs when the REDO log for one or more data nodes is out of date, so that a node restart is invoked for that node or those nodes. If this happens while a *Note `mysqld': mysqld. process is attached to the cluster as an SQL node, the *Note `mysqld': mysqld. takes a global schema lock (a row lock), while trying to set up cluster-internal replication. However, this setup process could fail, causing the global schema lock to be held for an excessive length of time, which made the node restart hang as well. As a result, the mysqld failed to set up cluster-internal replication, which led to tables being read only, and caused one node to hang during the restart. *Note*: This issue could actually occur in MySQL Cluster NDB 7.0 only, but the fix was also applied MySQL Cluster NDB 6.3, in order to keep the two codebases in alignment. (Bug #49560) * Sending `SIGHUP' to a *Note `mysqld': mysqld. running with the `--ndbcluster' and `--log-bin' options caused the process to crash instead of refreshing its log files. (Bug #49515) * If the master data node receiving a request from a newly-started API or data node for a node ID died before the request has been handled, the management server waited (and kept a mutex) until all handling of this node failure was complete before responding to any other connections, instead of responding to other connections as soon as it was informed of the node failure (that is, it waited until it had received a NF_COMPLETEREP signal rather than a NODE_FAILREP signal). On visible effect of this misbehavior was that it caused management client commands such as SHOW and ALL STATUS to respond with unnecessary slowness in such circumstances. (Bug #49207) * Attempting to create more than 11435 tables failed with Error 306 (`Out of fragment records in DIH'). (Bug #49156) * When evaluating the options `--include-databases', `--include-tables', `--exclude-databases', and `--exclude-tables', the *Note `ndb_restore': mysql-cluster-programs-ndb-restore. program overwrote the result of the database-level options with the result of the table-level options rather than merging these results together, sometimes leading to unexpected and unpredictable results. As part of the fix for this problem, the semantics of these options have been clarified; because of this, the rules governing their evaluation have changed slightly. These changes be summed up as follows: * All `--include-*' and `--exclude-*' options are now evaluated from right to left in the order in which they are passed to *Note `ndb_restore': mysql-cluster-programs-ndb-restore. * All `--include-*' and `--exclude-*' options are now cumulative. * In the event of a conflict, the first (rightmost) option takes precedence. For more detailed information and examples, see *Note mysql-cluster-programs-ndb-restore::. (Bug #48907) * When performing tasks that generated large amounts of I/O (such as when using *Note `ndb_restore': mysql-cluster-programs-ndb-restore.), an internal memory buffer could overflow, causing data nodes to fail with signal 6. Subsequent analysis showed that this buffer was not actually required, so this fix removes it. (Bug #48861) * Exhaustion of send buffer memory or long signal memory caused data nodes to crash. Now an appropriate error message is provided instead when this situation occurs. (Bug #48852) * In some situations, when it was not possible for an SQL node to start a schema transaction (necessary, for instance, as part of an online *Note `ALTER TABLE': alter-table.), *Note `NDBCLUSTER': mysql-cluster. did not correctly indicate the error to the MySQL server, which led *Note `mysqld': mysqld. to crash. (Bug #48841) * Under certain conditions, accounting of the number of free scan records in the local query handler could be incorrect, so that during node recovery or a local checkpoint operations, the LQH could find itself lacking a scan record that is expected to find, causing the node to crash. (Bug #48697) See also Bug #48564. * The creation of an ordered index on a table undergoing DDL operations could cause a data node crash under certain timing-dependent conditions. (Bug #48604) * During an LCP master takeover, when the newly elected master did not receive a `COPY_GCI' LCP protocol message but other nodes participating in the local checkpoint had received one, the new master could use an uninitialized variable, which caused it to crash. (Bug #48584) * When running many parallel scans, a local checkpoint (which performs a scan internally) could find itself not getting a scan record, which led to a data node crash. Now an extra scan record is reserved for this purpose, and a problem with obtaining the scan record returns an appropriate error (error code 489, `Too many active scans'). (Bug #48564) * During a node restart, logging was enabled on a per-fragment basis as the copying of each fragment was completed but local checkpoints were not enabled until all fragments were copied, making it possible to run out of redo log file space (*Note `NDB': mysql-cluster. error code 410) before the restart was complete. Now logging is enabled only after all fragments has been copied, just prior to enabling local checkpoints. (Bug #48474) * When using very large transactions containing many inserts, *Note `ndbmtd': mysql-cluster-programs-ndbmtd. could fail with Signal 11 without an easily detectable reason, due to an internal variable being unitialized in the event that the `LongMessageBuffer' was overloaded. Now, the variable is initialized in such cases, avoiding the crash, and an appropriate error message is generated. (Bug #48441) See also Bug #46914. * A data node crashing while restarting, followed by a system restart could lead to incorrect handling of redo log metadata, causing the system restart to fail with `Error while reading REDO log'. (Bug #48436) * Starting a *Note `mysqld': mysqld. process with `--ndb-nodeid' (either as a command-line option or by assigning it a value in `my.cnf') caused the *Note `mysqld': mysqld. to get only the corresponding connection from the `[mysqld]' section in the `config.ini' file having the matching ID, even when connection pooling was enabled (that is, when the *Note `mysqld': mysqld. process was started with `--ndb-cluster-connection-pool' set greater than 1). (Bug #48405) See also Bug #27644, Bug #38590, Bug #41592. * The configuration check that each management server runs to verify that all connected *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. processes have the same configuration could fail when a configuration change took place while this check was in progress. Now in such cases, the configuration check is rescheduled for a later time, after the change is complete. (Bug #48143) * When employing *Note `NDB': mysql-cluster. native backup to back up and restore an empty *Note `NDB': mysql-cluster. table that used a non-sequential `AUTO_INCREMENT' value, the `AUTO_INCREMENT' value was not restored correctly. (Bug #48005) * *Note `ndb_config `--xml' `--configinfo'': mysql-cluster-programs-ndb-config. now indicates that parameters belonging in the `[SCI]', `[SCI DEFAULT]', `[SHM]', and `[SHM DEFAULT]' sections of the `config.ini' file are deprecated or experimental, as appropriate. (Bug #47365) * *Note `NDB': mysql-cluster. stores blob column data in a separate, hidden table that is not accessible from MySQL. If this table was missing for some reason (such as accidental deletion of the file corresponding to the hidden table) when making a MySQL Cluster native backup, ndb_restore crashed when attempting to restore the backup. Now in such cases, ndb_restore fails with the error message `Table TABLE_NAME has blob column (COLUMN_NAME) with missing parts table in backup' instead. (Bug #47289) * In MySQL Cluster NDB 7.0, *Note `ndb_config': mysql-cluster-programs-ndb-config. and *Note `ndb_error_reporter': mysql-cluster-programs-ndb-error-reporter. were printing warnings about management and data nodes running on the same host to `stdout' instead of `stderr', as was the case in earlier MySQL Cluster release series. (Bug #44689, Bug #49160) See also Bug #25941. * *Note `DROP DATABASE': drop-database. failed when there were stale temporary *Note `NDB': mysql-cluster. tables in the database. This situation could occur if *Note `mysqld': mysqld. crashed during execution of a *Note `DROP TABLE': drop-table. statement after the table definition had been removed from *Note `NDBCLUSTER': mysql-cluster. but before the corresponding `.ndb' file had been removed from the crashed SQL node's data directory. Now, when *Note `mysqld': mysqld. executes *Note `DROP DATABASE': drop-database, it checks for these files and removes them if there are no corresponding table definitions for them found in *Note `NDBCLUSTER': mysql-cluster. (Bug #44529) * Creating an *Note `NDB': mysql-cluster. table with an excessive number of large *Note `BIT': numeric-types. columns caused the cluster to fail. Now, an attempt to create such a table is rejected with error 791 (`Too many total bits in bitfields'). (Bug #42046) See also Bug #42047. * When a long-running transaction lasting long enough to cause Error 410 (`REDO log files overloaded') was later committed or rolled back, it could happen that *Note `NDBCLUSTER': mysql-cluster. was not able to release the space used for the REDO log, so that the error condition persisted indefinitely. The most likely cause of such transactions is a bug in the application using MySQL Cluster. This fix should handle most cases where this might occur. (Bug #36500) * Deprecation and usage information obtained from *Note `ndb_config `--configinfo'': mysql-cluster-programs-ndb-config. regarding the `PortNumber' and `ServerPort' configuration parameters was improved. (Bug #24584) * *Disk Data*: When running a write-intensive workload with a very large disk page buffer cache, CPU usage approached 100% during a local checkpoint of a cluster containing Disk Data tables. (Bug #49532) * *Disk Data*: *Note `NDBCLUSTER': mysql-cluster. failed to provide a valid error message it failed to commit schema transactions during an initial start if the cluster was configured using the `InitialLogFileGroup' parameter. (Bug #48517) * *Disk Data*: In certain limited cases, it was possible when the cluster contained Disk Data tables for *Note `ndbmtd': mysql-cluster-programs-ndbmtd. to crash during a system restart. (Bug #48498) See also Bug #47832. * *Disk Data*: Repeatedly creating and then dropping Disk Data tables could eventually lead to data node failures. (Bug #45794, Bug #48910) * *Disk Data*: When a crash occurs due to a problem in Disk Data code, the currently active page list is printed to `stdout' (that is, in one or more `ndb_NODEID_out.log' files). One of these lists could contain an endless loop; this caused a printout that was effectively never-ending. Now in such cases, a maximum of 512 entries is printed from each list. (Bug #42431) * *Disk Data*: When the `FileSystemPathUndoFiles' configuration parameter was set to an non-existent path, the data nodes shut down with the generic error code 2341 (`Internal program error'). Now in such cases, the error reported is error 2815 (`File not found'). * *Cluster Replication*: When `expire_logs_days' was set, the thread performing the purge of the log files could deadlock, causing all binary log operations to stop. (Bug #49536) * *Cluster API*: When a DML operation failed due to a uniqueness violation on an *Note `NDB': mysql-cluster. table having more than one unique index, it was difficult to determine which constraint caused the failure; it was necessary to obtain an `NdbError' object, then decode its `details' property, which in could lead to memory management issues in application code. To help solve this problem, a new API method `Ndb::getNdbErrorDetail()' is added, providing a well-formatted string containing more precise information about the index that caused the unque constraint violation. The following additional changes are also made in the NDB API: * Use of `NdbError.details' is now deprecated in favor of the new method. * The `NdbDictionary::listObjects()' method has been modified to provide more information. For more information, see `Ndb::getNdbErrorDetail()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndb-methods.html#ndb-ndb-getndberrordetail), The `NdbError' Structure (http://dev.mysql.com/doc/ndbapi/en/ndb-ndberror.html#ndb-ndberror), and `Dictionary::listObjects()' (http://dev.mysql.com/doc/ndbapi/en/ndb-dictionary-methods.html#ndb-dictionary-listobjects). (Bug #48851) * *Cluster API*: When using blobs, calling `getBlobHandle()' requires the full key to have been set using `equal()', because `getBlobHandle()' must access the key for adding blob table operations. However, if `getBlobHandle()' was called without first setting all parts of the primary key, the application using it crashed. Now, an appropriate error code is returned instead. (Bug #28116, Bug #48973) * The *Note `mysql_real_connect()': mysql-real-connect. C API function only attempted to connect to the first IP address returned for a hostname. This could be a problem if a hostname mapped to multiple IP address and the server was not bound to the first one returned. Now *Note `mysql_real_connect()': mysql-real-connect. attempts to connect to all IPv4 or IPv6 addresses that a domain name maps to. (Bug #45017) See also Bug #47757.  File: manual.info, Node: mysql-cluster-news-5-1-39-ndb-7-0-9b, Next: mysql-cluster-news-5-1-39-ndb-7-0-9a, Prev: mysql-cluster-news-5-1-39-ndb-7-0-10, Up: mysql-cluster-news-7-0 17.7.3.26 Changes in MySQL Cluster NDB 7.0.9b (5.1.39-ndb-7.0.9b) (10 November 2009) .................................................................................... This release includes a fix for Bug#48651, which was discovered in MySQL Cluster NDB 7.0.9a shortly after release. The MySQL Cluster NDB 7.0.9b release is identical in all other respects to MySQL Cluster NDB 7.0.9a. Users who have already installed MySQL Cluster NDB 7.0.9a should upgrade to MySQL Cluster NDB 7.0.9b as soon as possible; users seeking to upgrade from any other previous MySQL Cluster 7.0 release should upgrade to MySQL Cluster NDB 7.0.9b instead. Obtaining MySQL Cluster NDB 7.0.9b The latest MySQL Cluster NDB 7.0 binaries for supported platforms can be obtained from `http://dev.mysql.com/downloads/cluster/'. Source code for the latest MySQL Cluster NDB 7.0 release can be obtained from the same location. You can also access the MySQL Cluster NDB 7.0 development source tree at `https://code.launchpad.net/~mysql/mysql-server/mysql-cluster-7.0'. This release also incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.1, 6.2, 6.3, and 7.0 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.39 (see *Note news-5-1-39::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Bugs fixed:* * Using a large number of small fragment log files could cause *Note `NDBCLUSTER': mysql-cluster. to crash while trying to read them during a restart. This issue was first observed with 1024 fragment log files of 16 MB each. (Bug #48651)  File: manual.info, Node: mysql-cluster-news-5-1-39-ndb-7-0-9a, Next: mysql-cluster-news-5-1-39-ndb-7-0-9, Prev: mysql-cluster-news-5-1-39-ndb-7-0-9b, Up: mysql-cluster-news-7-0 17.7.3.27 Changes in MySQL Cluster NDB 7.0.9a (5.1.39-ndb-7.0.9a) (05 November 2009) .................................................................................... *Important*: MySQL Cluster NDB 7.0.9a was pulled shortly after release due to Bug#48651. Users seeking to upgrade from a previous MySQL Cluster NDB 7.0 release should instead use MySQL Cluster NDB 7.0.9b, which contains a fix for this bug, in addition to all bugfixes and improvements made in MySQL Cluster NDB 7.0.9a. This release includes a fix for Bug#48531, which was discovered in MySQL Cluster NDB 7.0.9 shortly after release. The MySQL Cluster NDB 7.0.9a release is identical in all other respects to MySQL Cluster NDB 7.0.9. Users who have already installed MySQL Cluster NDB 7.0.9 should upgrade to MySQL Cluster NDB 7.0.9a as soon as possible; users seeking to upgrade from any other previous MySQL Cluster 7.0 release should upgrade to MySQL Cluster NDB 7.0.9a instead. This release also incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.1, 6.2, 6.3, and 7.0 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.39 (see *Note news-5-1-39::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Bugs fixed:* * When the combined length of all names of tables using the *Note `NDB': mysql-cluster. storage engine was greater than or equal to 1024 bytes, issuing the `START BACKUP' command in the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client caused the cluster to crash. (Bug #48531)  File: manual.info, Node: mysql-cluster-news-5-1-39-ndb-7-0-9, Next: mysql-cluster-news-5-1-37-ndb-7-0-8a, Prev: mysql-cluster-news-5-1-39-ndb-7-0-9a, Up: mysql-cluster-news-7-0 17.7.3.28 Changes in MySQL Cluster NDB 7.0.9 (5.1.39-ndb-7.0.9) (31 October 2009) ................................................................................. *Important*: MySQL Cluster NDB 7.0.9 and 7.0.9a were pulled shortly after being released due to Bug#48531 and Bug#48651. Users seeking to upgrade from a previous MySQL Cluster NDB 7.0 release should instead use MySQL Cluster NDB 7.0.9b, which contains fixes for these critical bugs, in addition to all bugfixes and improvements made in MySQL Cluster NDB 7.0.9. This release incorporates new features in the *Note `NDBCLUSTER': mysql-cluster. storage engine and fixes recently discovered bugs in MySQL Cluster NDB 7.0.8a. This release also incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.1, 6.2, 6.3, and 7.0 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.39 (see *Note news-5-1-39::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * *Performance*: Significant improvements in redo log handling and other file system operations can yield a considerable reduction in the time required for restarts. While actual restart times observed in a production setting will naturally vary according to database size, hardware, and other conditions, our own preliminary testing shows that these optimizations can yield startup times that are faster than those typical of previous MySQL Cluster releases by a factor of 50 or more. *Bugs fixed:* * *Important Change*: The `--with-ndb-port-base' option for `configure' did not function correctly, and has been deprecated. Attempting to use this option produces the warning `Ignoring deprecated option --with-ndb-port-base'. Beginning with MySQL Cluster NDB 7.1.0, the deprecation warning itself is removed, and the `--with-ndb-port-base' option is simply handled as an unknown and invalid option if you try to use it. (Bug #47941) See also Bug #38502. * After upgrading a MySQL Cluster containing tables having unique indexes from an NDB 6.3 release to an NDB 7.0 release, attempts to create new unique indexes failed with `inconsistent trigger' errors (error code 293). For more information (including a workaround for previous MySQL Cluster NDB 7.0 releases), see *Note mysql-cluster-upgrade-downgrade-compatibility-7.x::. (Bug #48416) * When a data node failed to start due to inability to recreate or drop objects during schema restoration (for example: insufficient memory was available to the data node process on account of issues not directly related to MySQL Cluster on the host machine), the reason for the failure was not provided. Now is such cases, a more informative error message is logged. (Bug #48232) * A table that was created following an upgrade from a MySQL Cluster NDB 6.3 release to MySQL Cluster NDB 7.0 (starting with version 6.4.0) or later was dropped by a system restart. This was due to a change in the format of `NDB' schema files and the fact that the upgrade of the format of existing `NDB' 6.3 schema files to the `NDB' 7.0 format failed to change the version number contained in the file; this meant that a system restart re-ran the upgrade routine, which interpreted the newly-created table as an uncommitted table (which by definition ought not to be saved). Now the version number of upgraded `NDB' 6.3 schema files is set correctly during the upgrade process. (Bug #48227) * In certain cases, performing very large inserts on `NDB' tables when using *Note `ndbmtd': mysql-cluster-programs-ndbmtd. caused the memory allocations for ordered or unique indexes (or both) to be exceeded. This could cause aborted transactions and possibly lead to data node failures. (Bug #48037) See also Bug #48113. * For *Note `UPDATE IGNORE': update. statements, batching of updates is now disabled. This is because such statements failed when batching of updates was employed if any updates violated a unique constraint, to the fact a unique constraint violation could not be handled without aborting the transaction. (Bug #48036) * Starting a data node with a very large amount of `DataMemory' (approximately 90G or more) could lead to crash of the node due to job buffer congestion. (Bug #47984) * In some cases, *Note `ndbmtd': mysql-cluster-programs-ndbmtd. could allocate more space for the undo buffer than was actually available, leading to a failure in the `LGMAN' kernel block and subsequent failure of the data node. (Bug #47966) * When an *Note `UPDATE': update. statement was issued against an *Note `NDB': mysql-cluster. table where an index was used to identify rows but no data was actually changed, the *Note `NDB': mysql-cluster. storage returned zero found rows. For example, consider the table created and populated using these statements: CREATE TABLE t1 ( c1 INT NOT NULL, c2 INT NOT NULL, PRIMARY KEY(c1), KEY(c2) ) ENGINE = NDB; INSERT INTO t1 VALUES(1, 1); The following *Note `UPDATE': update. statements, even though they did not change any rows, each still matched a row, but this was reported incorrectly in both cases, as shown here: mysql> UPDATE t1 SET c2 = 1 WHERE c1 = 1; Query OK, 0 rows affected (0.00 sec) Rows matched: 0 Changed: 0 Warnings: 0 mysql> UPDATE t1 SET c1 = 1 WHERE c2 = 1; Query OK, 0 rows affected (0.00 sec) Rows matched: 0 Changed: 0 Warnings: 0 Now in such cases, the number of rows matched is correct. (In the case of each of the example *Note `UPDATE': update. statements just shown, this is displayed as Rows matched: 1, as it should be.) This issue could affect *Note `UPDATE': update. statements involving any indexed columns in *Note `NDB': mysql-cluster. tables, regardless of the type of index (including `KEY', `UNIQUE KEY', and `PRIMARY KEY') or the number of columns covered by the index. (Bug #47955) * On Solaris, shutting down a management node failed when issuing the command to do so from a client connected to a different management node. (Bug #47948) * After changing the value of `DiskSyncSize' to 4294967039 (the maximum) in the `config.ini' file and reloading the cluster configuration, the new value was displayed in the update information written into the cluster log as a signed number instead of unsigned. (Bug #47944) See also Bug #47932. * On Solaris 10 for SPARC, *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. failed to parse the `config.ini' file when the `DiskSyncSize' configuration parameter, whose permitted range of values is 32768 to 4294967039, was set equal to 4294967040 (which is also the value of the internal constant `MAX_INT_RNIL'), nor could `DiskSyncSize' be set successfully any higher than the minimum value. (Bug #47932) See also Bug #47944. * Setting `FragmentLogFileSize' to a value greater than 256 MB led to errors when trying to read the redo log file. (Bug #47908) * *Note `SHOW CREATE TABLE': show-create-table. did not display the `AUTO_INCREMENT' value for `NDB' tables having `AUTO_INCREMENT' columns. (Bug #47865) * An optimization in MySQL Cluster NDB 7.0 causes the `DBDICT' kernel block to copy several tables at a time when synchronizing the data dictionary to a newly-started node; previously, this was done one table at a time. However, when `NDB' tables were sufficiently large and numerous, the internal buffer for storing them could fill up, causing a data node crash. In testing, it was found that having 100 `NDB' tables with 128 columns each was enough to trigger this issue. (Bug #47859) * Under some circumstances, when a scan encountered an error early in processing by the `DBTC' kernel block (see The `DBTC' Block (http://dev.mysql.com/doc/ndbapi/en/ndb-internals-kernel-blocks-dbtc.html)), a node could crash as a result. Such errors could be caused by applications sending incorrect data, or, more rarely, by a *Note `DROP TABLE': drop-table. operation executed in parallel with a scan. (Bug #47831) * When starting a node and synchronizing tables, memory pages were allocated even for empty fragments. In certain situations, this could lead to insufficient memory. (Bug #47782) * During an upgrade, newer nodes (NDB kernel block `DBTUP') could in some cases try to use the long signal format for communication with older nodes (`DBUTIL' kernel block) that did not understand the newer format, causing older data nodes to fail after restarting. (Bug #47740) * A very small race-condition between `NODE_FAILREP' and `LQH_TRANSREQ' signals when handling node failure could lead to operations (locks) not being taken over when they should have been, and subsequently becoming stale. This could lead to node restart failures, and applications getting into endless lock-conflicts with operations that were not released until the node was restarted. (Bug #47715) See also Bug #41297. * In some cases, the MySQL Server tried to use an error status whose value had never been set. The problem in the code that caused this, in `hostname.cc', manifested when using debug builds of *Note `mysqld': mysqld. in MySQL Cluster replication. This fix brings MySQL Cluster's error handling in `hostname.cc' in line with what is implemented in MySQL 5.4. (Bug #47548) * `configure' failed to honor the `--with-zlib-dir' option when trying to build MySQL Cluster from source. (Bug #47223) * Performing a system restart of the cluster after having performed a table reorganization which added partitions caused the cluster to become inconsistent, possibly leading to a forced shutdown, in either of the following cases: 1. When a local checkpoint was in progress but had not yet completed, new partitions were not restored; that is, data that was supposed to be moved could be lost instead, leading to an inconsistent cluster. This was due to an issue whereby the `DBDIH' kernel block did not save the new table definition and instead used the old one (the version having fewer partitions). 2. When the most recent LCP had completed, ordered indexes and unlogged tables were still not saved (since these did not participate in the LCP). In this case, the cluster crashed during a subsequent system restart, due to the inconsistency between the main table and the ordered index. Now, `DBDIH' is forced in such cases to use the version of the table definition held by the `DBDICT' kernel block, which was (already) correct and up to date. (Bug #46585) * *Note `ndbd': mysql-cluster-programs-ndbd. was not built correctly when compiled using `gcc' 4.4.0. (The *Note `ndbd': mysql-cluster-programs-ndbd. binary was built, but could not be started.) (Bug #46113) * *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. failed to close client connections that had timed out. After running for some time, a race condition could develop in the management server, due to *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. having exhausted all of its file descriptors in this fashion. (Bug #45497) See also Bug #47712. * If a node failed while sending a fragmented long signal, the receiving node did not free long signal assembly resources that it had allocated for the fragments of the long signal that had already been received. (Bug #44607) * Numeric configuration parameters set in `my.cnf' were interpreted as signed rather than unsigned values. The effect of this was that values of 2G or more were truncated with the warning `[MgmSrvr] Warning: option 'OPT_NAME': signed value OPT_VALUE adjusted to 2147483647'. Now such parameter values are treated as unsigned, so that this truncation does not take place. This issue did not effect parameters set in `config.ini'. (Bug #44448) * When starting a cluster with a great many tables, it was possible for MySQL client connections as well as the slave SQL thread to issue DML statements against MySQL Cluster tables before *Note `mysqld': mysqld. had finished connecting to the cluster and making all tables writeable. This resulted in `Table ... is read only' errors for clients and the Slave SQL thread. This issue is fixed by introducing the `--ndb-wait-setup' option for the MySQL server. This provides a configurable maximum amount of time that *Note `mysqld': mysqld. waits for all *Note `NDB': mysql-cluster. tables to become writeable, before enabling MySQL clients or the slave SQL thread to connect. (Bug #40679) See also Bug #46955. * When building MySQL Cluster, it was possible to configure the build using `--with-ndb-port' without supplying a port number. Now in such cases, `configure' fails with an error. (Bug #38502) See also Bug #47941. * When the MySQL server SQL mode included `STRICT_TRANS_TABLES', storage engine warnings and error codes specific to `NDB' were returned when errors occurred, instead of the MySQL server errors and error codes expected by some programming APIs (such as Connector/J) and applications. (Bug #35990) * When a copying operation exhausted the available space on a data node while copying large *Note `BLOB': blob. columns, this could lead to failure of the data node and a `Table is full' error on the SQL node which was executing the operation. Examples of such operations could include an *Note `ALTER TABLE': alter-table. that changed an *Note `INT': numeric-types. column to a *Note `BLOB': blob. column, or a bulk insert of *Note `BLOB': blob. data that failed due to running out of space or to a duplicate key error. (Bug #34583, Bug #48040) See also Bug #41674, Bug #45768. * *Replication*: When *Note `mysqlbinlog': mysqlbinlog. `--verbose' was used to read a binary log that had been written using row-based format, the output for events that updated some but not all columns of tables was not correct. (Bug #47323) * *Disk Data*: A local checkpoint of an empty fragment could cause a crash during a system restart which was based on that LCP. (Bug #47832) See also Bug #41915. * *Disk Data*: Multi-threaded data nodes could in some cases attempt to access the same memory structure in parallel, in a non-safe manner. This could result in data node failure when running *Note `ndbmtd': mysql-cluster-programs-ndbmtd. while using Disk Data tables. (Bug #44195) See also Bug #46507. * *Cluster Replication*: When using multiple active replication channels, it was sometimes possible that a node group would fail on the slave cluster, causing the slave cluster to shut down. (Bug #47935) * *Cluster Replication*: When recording a binary log using the `--ndb-log-update-as-write' and `--ndb-log-updated-only' options (both enabled by default) and later attempting to apply that binary log with *Note `mysqlbinlog': mysqlbinlog, any operations that were played back from the log but which updated only some (but not all) columns caused any columns that were not updated to be reset to their default values. (Bug #47674) See also Bug #47323, Bug #46662. * *Cluster Replication*: *Note `mysqlbinlog': mysqlbinlog. failed to apply correctly a binary log that had been recorded using `--ndb-log-update-as-write=1'. (Bug #46662) See also Bug #47323, Bug #47674. * *Cluster API*: If an NDB API program reads the same column more than once, it is possible exceed the maximum permissible message size, in which case the operation should be aborted due to NDB error 880 `Tried to read too much - too many getValue calls', however due to a change introduced in MySQL Cluster NDB 6.3.18, the check for this was not done correctly, which instead caused a data node crash. (Bug #48266) * *Cluster API*: The NDB API methods `Dictionary::listEvents()', `Dictionary::listIndexes()', `Dictionary::listObjects()', and `NdbOperation::getErrorLine()' formerly had both `const' and non-`const' variants. The non-`const' versions of these methods have been removed. In addition, the `NdbOperation::getBlobHandle()' method has been re-implemented to provide consistent internal semantics. (Bug #47798) * *Cluster API*: A duplicate read of a column caused NDB API applications to crash. (Bug #45282) * *Cluster API*: The error handling shown in the example file `ndbapi_scan.cpp' included with the MySQL Cluster distribution was incorrect. (Bug #39573) * Installation of MySQL on Windows would fail to set the correct location for the character set files, which could lead to *Note `mysqld': mysqld. and *Note `mysql': mysql. failing to initialize properly. (Bug #17270)  File: manual.info, Node: mysql-cluster-news-5-1-37-ndb-7-0-8a, Next: mysql-cluster-news-5-1-37-ndb-7-0-8, Prev: mysql-cluster-news-5-1-39-ndb-7-0-9, Up: mysql-cluster-news-7-0 17.7.3.29 Changes in MySQL Cluster NDB 7.0.8a (5.1.37-ndb-7.0.8a) (07 October 2009) ................................................................................... This release includes a fix for Bug#47844, which was discovered in MySQL Cluster NDB 7.0.8 shortly after release. The MySQL Cluster NDB 7.0.8a release is identical in all other respects to MySQL Cluster NDB 7.0.8. Users who have already installed MySQL Cluster NDB 7.0.8 should upgrade to MySQL Cluster NDB 7.0.8a as soon as possible; users seeking to upgrade from MySQL Cluster NDB 7.0.7 or another previous MySQL Cluster 7.0 release should upgrade to MySQL Cluster NDB 7.0.8a instead. Obtaining MySQL Cluster NDB 7.0.8a The latest MySQL Cluster NDB 7.0 binaries for supported platforms can be obtained from `http://dev.mysql.com/downloads/cluster/'. Source code for the latest MySQL Cluster NDB 7.0 release can be obtained from the same location. You can also access the MySQL Cluster NDB 7.0 development source tree at `https://code.launchpad.net/~mysql/mysql-server/mysql-cluster-7.0'. This release also incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.1, 6.2, 6.3, and 7.0 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.37 (see *Note news-5-1-37::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Bugs fixed:* * The disconnection of an API or SQL node having a node ID greater than 49 caused a forced shutdown of the cluster. (Bug #47844) * The error message text for *Note `NDB': mysql-cluster. error code 410 (`REDO log files overloaded...') was truncated. (Bug #23662)  File: manual.info, Node: mysql-cluster-news-5-1-37-ndb-7-0-8, Next: mysql-cluster-news-5-1-35-ndb-7-0-7, Prev: mysql-cluster-news-5-1-37-ndb-7-0-8a, Up: mysql-cluster-news-7-0 17.7.3.30 Changes in MySQL Cluster NDB 7.0.8 (5.1.37-ndb-7.0.8) (30 September 2009) ................................................................................... *Important*: MySQL Cluster NDB 7.0.8 was pulled shortly after release due to Bug#47844. Users seeking to upgrade from a previous MySQL Cluster NDB 7.0 release should instead use MySQL Cluster NDB 7.0.8a, which contains a fix for this bug, in addition to all bugfixes and improvements made in MySQL Cluster NDB 7.0.8. This release incorporates new features in the *Note `NDBCLUSTER': mysql-cluster. storage engine and fixes recently discovered bugs in MySQL Cluster NDB 7.0.7. This release also incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.1, 6.2, 6.3, and 7.0 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.37 (see *Note news-5-1-37::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * A new option `--log-name' is added for *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. This option can be used to provide a name for the current node and then to identify it in messages written to the cluster log. For more information, see *Note mysql-cluster-programs-ndb-mgmd::. (Bug #47643) * `--config-dir' is now accepted by *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. as an alias for the `--configdir' option. (Bug #42013) * *Disk Data*: Two new columns have been added to the output of *Note `ndb_desc': mysql-cluster-programs-ndb-desc. to make it possible to determine how much of the disk space allocated to a given table or fragment remains free. (This information is not available from the *Note `INFORMATION_SCHEMA.FILES': files-table. table, since the *Note `FILES': files-table. table applies only to Disk Data files.) For more information, see *Note mysql-cluster-programs-ndb-desc::. (Bug #47131) *Bugs fixed:* * *Important Change*: Previously, the MySQL Cluster management node and data node programs, when run on Windows platforms, required the `--nodaemon' option to produce console output. Now, these programs run in the foreground when invoked from the command line on Windows, which is the same behavior that *Note `mysqld.exe': mysqld. displays on Windows. (Bug #45588) * *Cluster Replication*: *Important Change*: In a MySQL Cluster acting as a replication slave and having multiple SQL nodes, only the SQL node receiving events directly from the master recorded DDL statements in its binary logs unless this SQL node also had binary logging enabled; otherwise, other SQL nodes in the slave cluster failed to log DDL statements, regardless of their individual `--log-bin' settings. The fix for this issue aligns binary logging of DDL statements with that of DML statements. In particular, you should take note of the following: * DDL and DML statements on the master cluster are logged with the server ID of the server that actually writes the log. * DDL and DML statements on the master cluster are logged by any attached *Note `mysqld': mysqld. that has binary logging enabled. * Replicated DDL and DML statements on the slave are logged by any attached mysqld that has both `--log-bin' and `--log-slave-updates' enabled. * Replicated DDL and DML statements are logged with the server ID of the original (master) MySQL server by any attached *Note `mysqld': mysqld. that has both `--log-bin' and `--log-slave-updates' enabled. Affect on upgrades When upgrading from a previous MySQL CLuster release, you should perform either one of the following: 1. Upgrade servers that are performing binary logging before those that are not; do not perform any DDL on `old' SQL nodes until all SQL nodes have been upgraded. 2. Make sure that `--log-slave-updates' is enabled on all SQL nodes performing binary logging prior to the upgrade, so that all DDL is captured. *Note*: Logging of DML statements was not affected by this issue. (Bug #45756) * The following issues with error logs generated by *Note `ndbmtd': mysql-cluster-programs-ndbmtd. were addressed: 1. The version string was sometimes truncated, or even not shown, depending on the number of threads in use (the more threads, the worse the problem). Now the version string is shown in full, as well as the filenames for all tracefiles (where available). 2. In the event of a crash, the thread number of the thread that crashed was not printed. Now this information is supplied, if available. (Bug #47629) * *Note `mysqld': mysqld. allocated an excessively large buffer for handling *Note `BLOB': blob. values due to overestimating their size. (For each row, enough space was allocated to accommodate _every_ *Note `BLOB': blob. or *Note `TEXT': blob. column value in the result set.) This could adversely affect performance when using tables containing *Note `BLOB': blob. or *Note `TEXT': blob. columns; in a few extreme cases, this issue could also cause the host system to run out of memory unexpectedly. (Bug #47574) See also Bug #47572, Bug #47573. * `NDBCLUSTER' uses a dynamically-allocated buffer to store *Note `BLOB': blob. or *Note `TEXT': blob. column data that is read from rows in MySQL Cluster tables. When an instance of the `NDBCLUSTER' table handler was recycled (this can happen due to table definition cache pressure or to operations such as *Note `FLUSH TABLES': flush. or *Note `ALTER TABLE': alter-table.), if the last row read contained blobs of zero length, the buffer was not freed, even though the reference to it was lost. This resulted in a memory leak. For example, consider the table defined and populated as shown here: CREATE TABLE t (a INT PRIMARY KEY, b LONGTEXT) ENGINE=NDB; INSERT INTO t VALUES (1, REPEAT('F', 20000)); INSERT INTO t VALUES (2, ''); Now execute repeatedly a *Note `SELECT': select. on this table, such that the zero-length *Note `LONGTEXT': blob. row is last, followed by a *Note `FLUSH TABLES': flush. statement (which forces the handler object to be re-used), as shown here: SELECT a, length(b) FROM bl ORDER BY a; FLUSH TABLES; Prior to the fix, this resulted in a memory leak proportional to the size of the stored *Note `LONGTEXT': blob. value each time these two statements were executed. (Bug #47573) See also Bug #47572, Bug #47574. * Large transactions involving joins between tables containing *Note `BLOB': blob. columns used excessive memory. (Bug #47572) See also Bug #47573, Bug #47574. * After an `NDB' table had an *Note `ALTER ONLINE TABLE': alter-table. operation performed on it in a MySQL Cluster running a MySQL Cluster NDB 6.3.x release, it could not be upgraded online to a MySQL Cluster NDB 7.0.x release. This issue was detected using MySQL Cluster NDB 6.3.20, but is likely to effect any MySQL Cluster NDB 6.3.x release supporting online DDL operations. (Bug #47542) * When using multi-threaded data nodes (*Note `ndbmtd': mysql-cluster-programs-ndbmtd.) with `NoOfReplicas' set to a value greater than 2, attempting to restart any of the data nodes caused a forced shutdown of the entire cluster. (Bug #47530) * A variable was left uninitialized while a data node copied data from its peers as part of its startup routine; if the starting node died during this phase, this could lead a crash of the cluster when the node was later restarted. (Bug #47505) * Handling of `LQH_TRANS_REQ' signals was done incorrectly in `DBLQH' when the transaction coordinator failed during a `LQH_TRANS_REQ' session. This led to incorrect handling of multiple node failures, particularly when using *Note `ndbmtd': mysql-cluster-programs-ndbmtd. (Bug #47476) * The NDB kernel's parser (in `ndb/src/common/util/Parser.cpp') did not interpret the backslash (``\'') character correctly. (Bug #47426) * During an online alter table operation, the new table definition was made available for users during the prepare-phase when it should only be exposed during and after a commit. This issue could affect NDB API applications, mysqld processes, or data node processes. (Bug #47375) * Aborting an online add column operation (for example, due to resource problems on a single data node, but not others) could lead to a forced node shutdown. (Bug #47364) * Clients attempting to connect to the cluster during shutdown could sometimes cause the management server to crash. (Bug #47325) * The size of the table descriptor pool used in the `DBTUP' kernel block was incorrect. This could lead to a data node crash when an LQH sent a `CREATE_TAB_REF' signal. (Bug #47215) See also Bug #44908. * When a data node restarts, it first runs the redo log until reaching the latest restorable global checkpoint; after this it scans the remainder of the redo log file, searching for entries that should be invalidated so they are not used in any subsequent restarts. (It is possible, for example, if restoring GCI number 25, that there might be entries belonging to GCI 26 in the redo log.) However, under certain rare conditions, during the invalidation process, the redo log files themselves were not always closed while scanning ahead in the redo log. In rare cases, this could lead to `MaxNoOfOpenFiles' being exceeded, causing a the data node to crash. (Bug #47171) * For very large values of `MaxNoOfTables' + `MaxNoOfAttributes', the calculation for `StringMemory' could overflow when creating large numbers of tables, leading to *Note `NDB': mysql-cluster. error 773 (`Out of string memory, please modify StringMemory config parameter'), even when `StringMemory' was set to `100' (100 percent). (Bug #47170) * The default value for the `StringMemory' configuration parameter, unlike other MySQL Cluster configuration parameters, was not set in `ndb/src/mgmsrv/ConfigInfo.cpp'. (Bug #47166) * Signals from a failed API node could be received after an `API_FAILREQ' signal (see Operations and Signals (http://dev.mysql.com/doc/ndbapi/en/ndb-internals-ndb-protocol-operations-signals.html)) has been received from that node, which could result in invalid states for processing subsequent signals. Now, all pending signals from a failing API node are processed before any `API_FAILREQ' signal is received. (Bug #47039) See also Bug #44607. * When reloading the management server configuration, only the last changed parameter was logged. (Bug #47036) * When using *Note `ndbmtd': mysql-cluster-programs-ndbmtd, a parallel *Note `DROP TABLE': drop-table. operation could cause data nodes to have different views of which tables should be included in local checkpoints; this discrepancy could lead to a node failure during an LCP. (Bug #46873) * Using triggers on *Note `NDB': mysql-cluster. tables caused `ndb_autoincrement_prefetch_sz' to be treated as having the NDB kernel's internal default value (32) and the value for this variable as set on the cluster's SQL nodes to be ignored. (Bug #46712) * Now, when started with `--initial' `--reload', *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. tries to copy the configuration of an existing *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. process with a confirmed configuration. This works only if the configuration files used by both management nodes are exactly the same. (Bug #45495, Bug #46488) See also Bug #42015. * On Windows, *Note `ndbd `--initial'': mysql-cluster-programs-ndbd. could hang in an endless loop while attempting to remove directories. (Bug #45402) * For multi-threaded data nodes, insufficient fragment records were allocated in the `DBDIH' NDB kernel block, which could lead to error 306 when creating many tables; the number of fragment records allocated did not take into account the number of LQH instances. (Bug #44908) * Running an *Note `ALTER TABLE': alter-table. statement while an *Note `NDB': mysql-cluster. backup was in progress caused *Note `mysqld': mysqld. to crash. (Bug #44695) * When performing auto-discovery of tables on individual SQL nodes, `NDBCLUSTER' attempted to overwrite existing `MyISAM' `.frm' files and corrupted them. Workaround In the *Note `mysql': mysql. client, create a new table (`t2') with same definition as the corrupted table (`t1'). Use your system shell or file manager to rename the old `.MYD' file to the new file name (for example, `mv t1.MYD t2.MYD'). In the *Note `mysql': mysql. client, repair the new table, drop the old one, and rename the new table using the old file name (for example, *Note `RENAME TABLE t2 TO t1': rename-table.). (Bug #42614) * When started with the `--initial' and `--reload' options, if *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. could not find a configuration file or connect to another management server, it appeared to hang. Now, when trying to fetch its configuration from another management node, *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. checks and signals (`Trying to get configuration from other mgmd(s)') each 30 seconds that it has not yet done so. (Bug #42015) See also Bug #45495. * Running *Note `ndb_restore': mysql-cluster-programs-ndb-restore. with the `--print' or `--print_log' option could cause it to crash. (Bug #40428, Bug #33040) * An insert on an *Note `NDB': mysql-cluster. table was not always flushed properly before performing a scan. One way in which this issue could manifest was that `LAST_INSERT_ID()' sometimes failed to return correct values when using a trigger on an *Note `NDB': mysql-cluster. table. (Bug #38034) * When a data node received a `TAKE_OVERTCCONF' signal from the master before that node had received a `NODE_FAILREP', a race condition could in theory result. (Bug #37688) See also Bug #25364, Bug #28717. * Some joins on large *Note `NDB': mysql-cluster. tables having *Note `TEXT': blob. or *Note `BLOB': blob. columns could cause *Note `mysqld': mysqld. processes to leak memory. The joins did not need to reference the *Note `TEXT': blob. or *Note `BLOB': blob. columns directly for this issue to occur. (Bug #36701) * On Mac OS X 10.5, commands entered in the management client failed and sometimes caused the client to hang, although management client commands invoked using the `--execute' (or `-e') option from the system shell worked normally. For example, the following command failed with an error and hung until killed manually, as shown here: ndb_mgm> SHOW `Warning, event thread startup failed, degraded printouts as result, errno=36' ^C However, the same management client command, invoked from the system shell as shown here, worked correctly: shell> ndb_mgm -e "SHOW" (Bug #35751) See also Bug #34438. * *Replication*: In some cases, a *Note `STOP SLAVE': stop-slave. statement could cause the replication slave to crash. This issue was specific to MySQL on Windows or Macintosh platforms. (Bug #45238, Bug #45242, Bug #45243, Bug #46013, Bug #46014, Bug #46030) See also Bug #40796. * *Disk Data*: Calculation of free space for Disk Data table fragments was sometimes done incorrectly. This could lead to unnecessary allocation of new extents even when sufficient space was available in existing ones for inserted data. In some cases, this might also lead to crashes when restarting data nodes. *Note*: This miscalculation was not reflected in the contents of the *Note `INFORMATION_SCHEMA.FILES': files-table. table, as it applied to extents allocated to a fragment, and not to a file. (Bug #47072) * *Cluster API*: In some circumstances, if an API node encountered a data node failure between the creation of a transaction and the start of a scan using that transaction, then any subsequent calls to `startTransaction()' and `closeTransaction()' could cause the same transaction to be started and closed repeatedly. (Bug #47329) * *Cluster API*: Performing multiple operations using the same primary key within the same `NdbTransaction::execute()' call could lead to a data node crash. *Note*: This fix does not make change the fact that performing multiple operations using the same primary key within the same `execute()' is not supported; because there is no way to determine the order of such operations, the result of such combined operations remains undefined. (Bug #44065) See also Bug #44015. * *API*: The fix for Bug#24507 could lead in some cases to client application failures due to a race condition. Now the server waits for the `dummy' thread to return before exiting, thus making sure that only one thread can initialize the POSIX threads library. (Bug #42850)  File: manual.info, Node: mysql-cluster-news-5-1-35-ndb-7-0-7, Next: mysql-cluster-news-5-1-34-ndb-7-0-6, Prev: mysql-cluster-news-5-1-37-ndb-7-0-8, Up: mysql-cluster-news-7-0 17.7.3.31 Changes in MySQL Cluster NDB 7.0.7 (5.1.35-ndb-7.0.7) (26 August 2009) ................................................................................ This release incorporates new features in the *Note `NDBCLUSTER': mysql-cluster. storage engine and fixes recently discovered bugs in MySQL Cluster NDB 7.0.6. Obtaining MySQL Cluster NDB 7.0.7 The latest MySQL Cluster NDB 7.0 binaries for supported platforms can be obtained from `http://dev.mysql.com/downloads/cluster/'. Source code for the latest MySQL Cluster NDB 7.0 release can be obtained from the same location. You can also access the MySQL Cluster NDB 7.0 development source tree at `https://code.launchpad.net/~mysql/mysql-server/mysql-cluster-7.0'. This release also incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.1, 6.2, 6.3, and 7.0 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.35 (see *Note news-5-1-35::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * *Important Change*: The default value of the `DiskIOThreadPool' data node configuration parameter has changed from 8 to 2. * On Solaris platforms, the MySQL Cluster management server and NDB API applications now use `CLOCK_REALTIME' as the default clock. (Bug #46183) * Formerly, node IDs were represented in the cluster log using a complex hexadecimal/binary encoding scheme. Now, node IDs are reported in the cluster log using numbers in standard decimal notation. (Bug #44248) * A new option `--exclude-missing-columns' has been added for the *Note `ndb_restore': mysql-cluster-programs-ndb-restore. program. In the event that any tables in the database or databases being restored to have fewer columns than the same-named tables in the backup, the extra columns in the backup's version of the tables are ignored. For more information, see *Note mysql-cluster-programs-ndb-restore::. (Bug #43139) * *Note*: This issue, originally resolved in MySQL 5.1.16, re-occurred due to a later (unrelated) change. The fix has been re-applied. (Bug #25984) * Previously, it was possible to disable arbitration only by setting `ArbitrationRank' to 0 on all management and API nodes. A new data node configuration parameter `Arbitration' simplifies this task; to disable arbitration, you can now use `Arbitration = Disabled' in the `[ndbd default]' section of the `config.ini' file. It is now also possible to configure arbitration in such a way that the cluster waits until the time determined by `ArbitrationTimeout' passes for an external manager to perform arbitration instead of handling it internally. This can be done by setting `Arbitration = WaitExternal' in the `[ndbd default]' section of the `config.ini' file. The default value for the Arbitration parameter is `Default', which permits arbitration to proceed normally, as determined by the `ArbitrationRank' settings for the management and API nodes. For more information, see *Note mysql-cluster-ndbd-definition::. *Bugs fixed:* * *Important Change*: The IPv6 loopback address `::1' was interpeted as a hostname rather than a numeric IP address. In addition, the IPv6-enabled server on Windows interpeted the hostname `localhost' as `::1' only, which failed to match the default `'root'@'127.0.0.1'' account in the `mysql.user' privilege table. *Note*: As a result of this fix, a `'root'@'::1'' account is added to the `mysql.user' table as one of the default accounts created during MySQL installation. (Bug #43006) See also Bug #38247, Bug #45283, Bug #45584, Bug #45606. * *Packaging*: The `pkg' installer for MySQL Cluster on Solaris did not perform a complete installation due to an invalid directory reference in the postinstall script. (Bug #41998) * The output from *Note `ndb_config': mysql-cluster-programs-ndb-config. `--configinfo' `--xml' contained quote characters (`"') within quoted XML attributes, causing it to be not well-formed. (Bug #46891) * When using multi-threaded data node processes (*Note `ndbmtd': mysql-cluster-programs-ndbmtd.), it was possible for LQH threads to continue running even after all *Note `NDB': mysql-cluster. tables had been dropped. This meant that dropping the last remaining *Note `NDB': mysql-cluster. table during a local checkpoint could cause multi-threaded data nodes to fail. (Bug #46890) * During a global checkpoint, LQH threads could run unevenly, causing a circular buffer oveflow by the Subscription Manager, which led to data node failure. (Bug #46782) See also Bug #46123, Bug #46723, Bug #45612. * Restarting the cluster following a local checkpoint and an online *Note `ALTER TABLE': alter-table. on a non-empty table caused data nodes to crash. (Bug #46651) * A combination of index creation and drop operations (or creating and dropping tables having indexes) with node and system restarts could lead to a crash. (Bug #46552) * Following an upgrade from MySQL Cluster NDB 6.3.x to MySQL Cluster NDB 7.0.6, DDL and backup operations failed. (Bug #46494, Bug #46563) * Full table scans failed to execute when the cluster contained more than 21 table fragments. *Note*: The number of table fragments in the cluster can be calculated as the number of data nodes, times 8 (that is, times the value of the internal constant `MAX_FRAG_PER_NODE'), divided by the number of replicas. Thus, when `NoOfReplicas = 1' at least 3 data nodes were required to trigger this issue, and when `NoOfReplicas = 2' at least 4 data nodes were required to do so. (Bug #46490) * Killing MySQL Cluster nodes immediately following a local checkpoint could lead to a crash of the cluster when later attempting to perform a system restart. The exact sequence of events causing this issue was as follows: 1. Local checkpoint occurs. 2. Immediately following the LCP, kill the master data node. 3. Kill the remaining data nodes within a few seconds of killing the master. 4. Attempt to restart the cluster. (Bug #46412) * Creating an index when the cluster had run out of table records could cause data nodes to crash. (Bug #46295) * Ending a line in the `config.ini' file with an extra semicolon character (`;') caused reading the file to fail with a parsing error. (Bug #46242) * When combining an index scan and a delete with a primary key delete, the index scan and delete failed to initialize a flag properly. This could in rare circumstances cause a data node to crash. (Bug #46069) * *Note `OPTIMIZE TABLE': optimize-table. on an *Note `NDB': mysql-cluster. table could in some cases cause SQL and data nodes to crash. This issue was observed with both *Note `ndbd': mysql-cluster-programs-ndbd. and *Note `ndbmtd': mysql-cluster-programs-ndbmtd. (Bug #45971) * The `AutoReconnect' configuration parameter for API nodes (including SQL nodes) has been added. This is intended to prevent API nodes from re-using allocated node IDs during cluster restarts. For more information, see *Note mysql-cluster-api-definition::. This fix also introduces two new methods of the NDB API `Ndb_cluster_connection' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndb-cluster-connection.html#ndb-ndb-cluster-connection) class: `set_auto_reconnect()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndb-cluster-connection-methods.html#ndb-ndb-cluster-connection-set-auto-reconnect) and `get_auto_reconnect()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndb-cluster-connection-methods.html#ndb-ndb-cluster-connection-get-auto-reconnect). (Bug #45921) * DML statements run during an upgrade from MySQL Cluster NDB 6.3 to NDB 7.0 were not handled correctly. (Bug #45917) * On Windows, the internal `basestring_vsprintf()' function did not return a POSIX-compliant value as expected, causing the management server to crash when trying to start a MySQL Cluster with more than 4 data nodes. (Bug #45733) * The signals used by *Note `ndb_restore': mysql-cluster-programs-ndb-restore. to send progress information about backups to the cluster log accessed the cluster transporter without using any locks. Because of this, it was theoretically possible that these signals could be interefered with by heartbeat signals if both were sent at the same time, causing the *Note `ndb_restore': mysql-cluster-programs-ndb-restore. messages to be corrupted. (Bug #45646) * Due to changes in the way that *Note `NDBCLUSTER': mysql-cluster. handles schema changes (implementation of schema transactions) in MySQL Cluster NDB 7.0, it was not possible to create MySQL Cluster tables having more than 16 indexes using a single *Note `CREATE TABLE': create-table. statement. This issue occurs only in MySQL Cluster NDB 7.0 releases prior to 7.0.7 (including releases numbered NDB 6.4.x). If you are not yet able to upgrade from an earlier MySQL Cluster NDB 7.0 release, you can work around this problem by creating the table without any indexes, then adding the indexes using a separate *Note `CREATE INDEX': create-index. statement for each index. (Bug #45525) * `storage/ndb/src/common/util/CMakeLists.txt' did not build the `BaseString-t' test program for Windows as the equivalent `storage/ndb/src/common/util/Makefile.am' does when building MySQL Cluster on Unix platforms. (Bug #45099) * Problems could arise when using *Note `VARCHAR': char. columns whose size was greater than 341 characters and which used the `utf8_unicode_ci' collation. In some cases, this combination of conditions could cause certain queries and *Note `OPTIMIZE TABLE': optimize-table. statements to crash *Note `mysqld': mysqld. (Bug #45053) * The warning message `Possible bug in Dbdih::execBLOCK_COMMIT_ORD ...' could sometimes appear in the cluster log. This warning is obsolete, and has been removed. (Bug #44563) * Debugging code causing *Note `ndbd': mysql-cluster-programs-ndbd. to use file compression on NTFS file systems failed with an error. (The code was removed.) This issue affected debug builds of MySQL Cluster on Windows platforms only. (Bug #44418) * *Note `ALTER TABLE REORGANIZE PARTITION': alter-table. could fail with Error 741 (`Unsupported alter table') if the appropriate hash-map was not present. This could occur when adding nodes online; for example, when going from 2 data nodes to 3 data nodes with `NoOfReplicas=1', or from 4 data nodes to 6 data nodes with `NoOfReplicas=2'. (Bug #44301) * Previously, a `GCP STOP' event was written to the cluster log as an `INFO' event. Now it is logged as a `WARNING' event instead. (Bug #43853) * In some cases, *Note `OPTIMIZE TABLE': optimize-table. on an *Note `NDB': mysql-cluster. table did not free any `DataMemory'. (Bug #43683) * If the cluster crashed during the execution of a *Note `CREATE LOGFILE GROUP': create-logfile-group. statement, the cluster could not be restarted afterward. (Bug #36702) See also Bug #34102. * *Disk Data*: *Partitioning*: An *Note `NDB': mysql-cluster. table created with a very large value for the `MAX_ROWS' option could--if this table was dropped and a new table with fewer partitions, but having the same table ID, was created--cause *Note `ndbd': mysql-cluster-programs-ndbd. to crash when performing a system restart. This was because the server attempted to examine each partition whether or not it actually existed. (Bug #45154) See also Bug #58638. * *Disk Data*: If the value set in the `config.ini' file for `FileSystemPathDD', `FileSystemPathDataFiles', or `FileSystemPathUndoFiles' was identical to the value set for `FileSystemPath', that parameter was ignored when starting the data node with `--initial' option. As a result, the Disk Data files in the corresponding directory were not removed when performing an initial start of the affected data node or data nodes. (Bug #46243) * For an IPv6-enabled MySQL server, privileges specified using standard IPv4 addresses for hosts were not matched (only IPv4-mapped addresses were handled correctly). As part of the fix for this bug, a new build option `--disable-ipv6' has been introduced. Compiling MySQL with this option causes all IPv6-specific code in the server to be ignored. *Important*: If the server has been compiled using `--disable-ipv6', it is not able to resolve hostnames correctly when run in an IPv6 environment. (Bug #45606) See also Bug #38247, Bug #43006, Bug #45283, Bug #45584. * The hostname cache failed to work correctly. (Bug #45584) See also Bug #38247, Bug #43006, Bug #45283, Bug #45606. * The number of connection errors from a given host as counted by the server was periodically reset, with the result that `max_connect_errors' was never reached and invalid hosts were never blocked from trying to connect. (Bug #45283) See also Bug #38247, Bug #43006, Bug #45584, Bug #45606. * An IPv6-enabled MySQL server did not resolve the IP addresses of incoming connections correctly, with the result that a connection that attempted to match any privilege table entries using fully-qualified domain names for hostnames or hostnames using wildcards were dropped. (Bug #38247) See also Bug #43006, Bug #45283, Bug #45584, Bug #45606.  File: manual.info, Node: mysql-cluster-news-5-1-34-ndb-7-0-6, Next: mysql-cluster-news-5-1-32-ndb-7-0-5, Prev: mysql-cluster-news-5-1-35-ndb-7-0-7, Up: mysql-cluster-news-7-0 17.7.3.32 Changes in MySQL Cluster NDB 7.0.6 (5.1.34-ndb-7.0.6) (26 May 2009) ............................................................................. This release incorporates new features in the *Note `NDBCLUSTER': mysql-cluster. storage engine and fixes recently discovered bugs in MySQL Cluster NDB 7.0.5. Obtaining MySQL Cluster NDB 7.0.5 The latest MySQL Cluster NDB 7.0 binaries for supported platforms can be obtained from `http://dev.mysql.com/downloads/cluster/'. Source code for the latest MySQL Cluster NDB 7.0 release can be obtained from the same location. You can also access the MySQL Cluster NDB 7.0 development source tree at `https://code.launchpad.net/~mysql/mysql-server/mysql-cluster-7.0'. This release also incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.1, 6.2, 6.3, and 7.0 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.34 (see *Note news-5-1-34::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * The *Note `ndb_config': mysql-cluster-programs-ndb-config. utility program can now provide an offline dump of all MySQL Cluster configuration parameters including information such as default and permitted values, brief description, and applicable section of the `config.ini' file. A dump in text format is produced when running *Note `ndb_config': mysql-cluster-programs-ndb-config. with the new `--configinfo' option, and in XML format when the options `--configinfo --xml' are used together. For more information and examples, see *Note mysql-cluster-programs-ndb-config::. *Bugs fixed:* * *Important Change*: *Partitioning*: User-defined partitioning of an *Note `NDBCLUSTER': mysql-cluster. table without any primary key sometimes failed, and could cause *Note `mysqld': mysqld. to crash. Now, if you wish to create an *Note `NDBCLUSTER': mysql-cluster. table with user-defined partitioning, the table must have an explicit primary key, and all columns listed in the partitioning expression must be part of the primary key. The hidden primary key used by the *Note `NDBCLUSTER': mysql-cluster. storage engine is not sufficient for this purpose. However, if the list of columns is empty (that is, the table is defined using `PARTITION BY [LINEAR] KEY()'), then no explicit primary key is required. This change does not effect the partitioning of tables using any storage engine other than *Note `NDBCLUSTER': mysql-cluster. (Bug #40709) * *Important Change*: Previously, the configuration parameter `NoOfReplicas' had no default value. Now the default for `NoOfReplicas' is 2, which is the recommended value in most settings. (Bug #44746) * *Important Note*: It was not possible to perform an online upgrade from any MySQL Cluster NDB 6.x release to MySQL Cluster NDB 7.0.5 or any to earlier MySQL Cluster NDB 7.0 release. With this fix, it is possible in MySQL Cluster NDB 7.0.6 and later to perform online upgrades from MySQL Cluster NDB 6.3.8 and later MySQL Cluster NDB 6.3 releases, or from MySQL Cluster NDB 7.0.5 or later MySQL Cluster NDB 7.0 releases. Online upgrades to MySQL Cluster NDB 7.0 releases previous to MySQL Cluster NDB 7.0.6 from earlier MySQL Cluster releases remain unsupported; online upgrades from MySQL Cluster NDB 7.0 releases previous to MySQL Cluster NDB 7.0.5 (including NDB 6.4.x beta releases) to later MySQL Cluster NDB 7.0 releases also remain unsupported. (Bug #44294) * An internal NDB API buffer was not properly initialized. (Bug #44977) * When a data node had written its GCI marker to the first page of a megabyte, and that node was later killed during restart after having processed that page (marker) but before completing a LCP, the data node could fail with file system errors. (Bug #44952) See also Bug #42564, Bug #44291. * When restarting a data nodes, management and API nodes reconnecting to it failed to re-use existing ports that had already been dynamically allocated for communications with that data node. (Bug #44866) * When *Note `ndb_config': mysql-cluster-programs-ndb-config. could not find the file referenced by the `--config-file' option, it tried to read `my.cnf' instead, then failed with a misleading error message. (Bug #44846) * When a data node was down so long that its most recent local checkpoint depended on a global checkpoint that was no longer restorable, it was possible for it to be unable to use optimized node recovery when being restarted later. (Bug #44844) See also Bug #26913. * Online upgrades to MySQL Cluster NDB 7.0 from a MySQL Cluster NDB 6.3 release could fail due to changes in the handling of key lengths and unique indexes during node recovery. (Bug #44827) * *Note `ndb_config `--xml'': mysql-cluster-programs-ndb-config. did not output any entries for the `HostName' parameter. In addition, the default listed for `MaxNoOfFiles' was outside the permitted range of values. (Bug #44749) See also Bug #44685, Bug #44746. * The output of *Note `ndb_config `--xml'': mysql-cluster-programs-ndb-config. did not provide information about all sections of the configuration file. (Bug #44685) See also Bug #44746, Bug #44749. * Use of `__builtin_expect()' had the side effect that compiler warnings about misuse of `=' (assignment) instead of `==' in comparisons were lost when building in debug mode. This is no longer employed when configuring the build with the `--with-debug' option. (Bug #44570) See also Bug #44567. * Inspection of the code revealed that several assignment operators (`=') were used in place of comparison operators (`==') in `DbdihMain.cpp'. (Bug #44567) See also Bug #44570. * When using large numbers of configuration parameters, the management server took an excessive amount of time (several minutes or more) to load these from the configuration cache when starting. This problem occurred when there were more than 32 configuration parameters specified, and became progressively worse with each additional multiple of 32 configuration parameters. (Bug #44488) * Building the MySQL Cluster NDB 7.0 tree failed when using the `icc' compiler. (Bug #44310) * SSL connections to SQL nodes failed on big-endian platforms. (Bug #44295) * Signals providing node state information (`NODE_STATE_REP' and `CHANGE_NODE_STATE_REQ') were not propagated to all blocks of *Note `ndbmtd': mysql-cluster-programs-ndbmtd. This could cause the following problems: * Inconsistent redo logs when performing a graceful shutdown; * Data nodes crashing when later restarting the cluster, data nodes needing to perform node recovery during the system restart, or both. (Bug #44291) See also Bug #42564. * An NDB internal timing function did not work correctly on Windows and could cause *Note `mysqld': mysqld. to fail on some AMD processors, or when running inside a virtual machine. (Bug #44276) * It was possible for NDB API applications to insert corrupt data into the database, which could subquently lead to data node crashes. Now, stricter checking is enforced on input data for inserts and updates. (Bug #44132) * *Note `ndb_restore': mysql-cluster-programs-ndb-restore. failed when trying to restore data on a big-endian machine from a backup file created on a little-endian machine. (Bug #44069) * Repeated starting and stopping of data nodes could cause ndb_mgmd to fail. This issue was observed on Solaris/SPARC. (Bug #43974) * A number of incorrectly formatted output strings in the source code caused compiler warnings. (Bug #43878) * When trying to use a data node with an older version of the management server, the data node crashed on startup. (Bug #43699) * In some cases, data node restarts during a system restart could fail due to insufficient redo log space. (Bug #43156) * *Note `NDBCLUSTER': mysql-cluster. did not build correctly on Solaris 9 platforms. (Bug #39080) See also Bug #39036, Bug #39038. * The output of *Note `ndbd `--help'': mysql-cluster-programs-ndbd. did not provide clear information about the program's `--initial' and `--initial-start' options. (Bug #28905) * It was theoretically possible for the value of a nonexistent column to be read as `NULL', rather than causing an error. (Bug #27843) * *Disk Data*: During a checkpoint, restore points are created for both the on-disk and in-memory parts of a Disk Data table. Under certain rare conditions, the in-memory restore point could include or exclude a row that should have been in the snapshot. This would later lead to a crash during or following recovery. This issue was somewhat more likely to be encountered when using *Note `ndbmtd': mysql-cluster-programs-ndbmtd. (Bug #41915) See also Bug #47832. * *Disk Data*: This fix supercedes and improves on an earlier fix made for this bug in MySQL 5.1.18. (Bug #24521) * *Cluster Replication*: A failure when setting up replication events could lead to subsequent data node failures. (Bug #44915)  File: manual.info, Node: mysql-cluster-news-5-1-32-ndb-7-0-5, Next: mysql-cluster-news-5-1-32-ndb-7-0-4, Prev: mysql-cluster-news-5-1-34-ndb-7-0-6, Up: mysql-cluster-news-7-0 17.7.3.33 Changes in MySQL Cluster NDB 7.0.5 (5.1.32-ndb-7.0.5) (20 April 2009 General Availability) .................................................................................................... This _General Availability_ (GA) release incorporates new features in the *Note `NDBCLUSTER': mysql-cluster. storage engine and fixes recently discovered bugs in MySQL Cluster NDB 7.0.4. Obtaining MySQL Cluster NDB 7.0.5 The latest MySQL Cluster NDB 7.0 binaries for supported platforms can be obtained from `http://dev.mysql.com/downloads/cluster/'. Source code for the latest MySQL Cluster NDB 7.0 release can be obtained from the same location. You can also access the MySQL Cluster NDB 7.0 development source tree at `https://code.launchpad.net/~mysql/mysql-server/mysql-cluster-7.0'. This release also incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.1, 6.2, 6.3, and 6.4 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.32 (see *Note news-5-1-32::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * Two new server status variables `Ndb_scan_count' and `Ndb_pruned_scan_count' have been introduced. `Ndb_scan_count' gives the number of scans executed since the cluster was last started. `Ndb_pruned_scan_count' gives the number of scans for which *Note `NDBCLUSTER': mysql-cluster. was able to use partition pruning. Together, these variables can be used to help determine in the MySQL server whether table scans are pruned by *Note `NDBCLUSTER': mysql-cluster. (Bug #44153) *Bugs fixed:* * *Important Note*: Due to problem discovered after the code freeze for this release, it is not possible to perform an online upgrade from any MySQL Cluster NDB 6.x release to MySQL Cluster NDB 7.0.5 or any earlier MySQL Cluster NDB 7.0 release. This issue is fixed in MySQL Cluster NDB 7.0.6 and later for upgrades from MySQL Cluster NDB 6.3.8 and later MySQL Cluster NDB 6.3 releases, or from MySQL Cluster NDB 7.0.5. (Bug #44294) * *Cluster Replication*: If data node failed during an event creation operation, there was a slight risk that a surviving data node could send an invalid table reference back to NDB, causing the operation to fail with a false Error 723 (`No such table'). This could take place when a data node failed as a *Note `mysqld': mysqld. process was setting up MySQL Cluster Replication. (Bug #43754) * *Cluster API*: The following issues occurred when performing an online (rolling) upgrade of a cluster to a version of MySQL Cluster that supports configuration caching from a version that does not: 1. When using multiple management servers, after upgrading and restarting one *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd, any remaining management servers using the previous version of *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. could not synchronize their configuration data. 2. The MGM API `ndb_mgm_get_configuration_nodeid()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-get-configuration-nodeid.html) function failed to obtain configuration data. (Bug #43641) * If the number of fragments per table rises above a certain threshold, the `DBDIH' kernel block's on-disk table-definition grows large enough to occupy 2 pages. However, in MySQL Cluster NDB 7.0 (including MySQL Cluster NDB 6.4 releases), only 1 page was actually written, causing table definitions stored on disk to be incomplete. This issue was not observed in MySQL Cluster release series prior to MySQL Cluster NDB 7.0. (Bug #44135) * `TransactionDeadlockDetectionTimeout' values less than 100 were treated as 100. This could cause scans to time out unexpectedly. (Bug #44099) * The file `ndberror.c' contained a C++-style comment, which caused builds to fail with some C compilers. (Bug #44036) * A race condition could occur when a data node failed to restart just before being included in the next global checkpoint. This could cause other data nodes to fail. (Bug #43888) * The setting for `ndb_use_transactions' was ignored. This issue was only known to occur in MySQL Cluster NDB 6.4.3 and MySQL Cluster NDB 7.0.4. (Bug #43236) * When a data node process had been killed after allocating a node ID, but before making contact with any other data node processes, it was not possible to restart it due to a node ID allocation failure. This issue could effect either *Note `ndbd': mysql-cluster-programs-ndbd. or *Note `ndbmtd': mysql-cluster-programs-ndbmtd. processes. (Bug #43224) This regression was introduced by Bug #42973. * *Note `ndb_restore': mysql-cluster-programs-ndb-restore. crashed when trying to restore a backup made to a MySQL Cluster running on a platform having different endianness from that on which the original backup was taken. (Bug #39540) * PID files for the data and management node daemons were not removed following a normal shutdown. (Bug #37225) * *Note `ndb_restore `--print_data'': mysql-cluster-programs-ndb-restore. did not handle *Note `DECIMAL': numeric-types. columns correctly. (Bug #37171) * Invoking the management client `START BACKUP' command from the system shell (for example, as *Note `ndb_mgm -e "START BACKUP"': mysql-cluster-programs-ndb-mgm.) did not work correctly, unless the backup ID was included when the command was invoked. Now, the backup ID is no longer required in such cases, and the backup ID that is automatically generated is printed to stdout, similar to how this is done when invoking `START BACKUP' within the management client. (Bug #31754) * When aborting an operation involving both an insert and a delete, the insert and delete were aborted separately. This was because the transaction coordinator did not know that the operations affected on same row, and, in the case of a committed-read (tuple or index) scan, the abort of the insert was performed first, then the row was examined after the insert was aborted but before the delete was aborted. In some cases, this would leave the row in a inconsistent state. This could occur when a local checkpoint was performed during a backup. This issue did not affect primary ley operations or scans that used locks (these are serialized). After this fix, for ordered indexes, all operations that follow the operation to be aborted are now also aborted. * *Disk Data*: When using multi-threaded data nodes, *Note `DROP TABLE': drop-table. statements on Disk Data tables could hang. (Bug #43825) * *Disk Data*: This fix completes one that was made for this issue in MySQL Cluster NDB-7.0.4, which did not rectify the problem in all cases. (Bug #43632) * *Cluster Replication*: When creating or altering a table an `NdbEventOperation' is created by the *Note `mysqld': mysqld. process to monitor the table for subsequent logging in the binlog. If this happened during a node restart there was a chance that the reference count on this event operation object could be incorrect, which could lead to an assert in debug MySQL Cluster builds. (Bug #43752) * *Cluster API*: If the largest offset of a `RecordSpecification' used for an `NdbRecord' object was for the `NULL' bits (and thus not a column), this offset was not taken into account when calculating the size used for the `RecordSpecification'. This meant that the space for the `NULL' bits could be overwritten by key or other information. (Bug #43891) * *Cluster API*: *Note `BIT': numeric-types. columns created using the native NDB API format that were not created as nullable could still sometimes be overwritten, or cause other columns to be overwritten. This issue did not effect tables having *Note `BIT': numeric-types. columns created using the mysqld format (always used by MySQL Cluster SQL nodes). (Bug #43802)  File: manual.info, Node: mysql-cluster-news-5-1-32-ndb-7-0-4, Next: mysql-cluster-news-5-1-32-ndb-6-4-3, Prev: mysql-cluster-news-5-1-32-ndb-7-0-5, Up: mysql-cluster-news-7-0 17.7.3.34 Changes in MySQL Cluster NDB 7.0.4 (5.1.32-ndb-7.0.4) (18 March 2008) ............................................................................... This is a new Beta development release, incorporating new features in the *Note `NDBCLUSTER': mysql-cluster. storage engine and fixing recently discovered bugs in MySQL Cluster NDB 6.4.3. All feature additions and bugfixes that were made in MySQL Cluster releases having NDB 6.4.x release numbers are included in MySQL Cluster 7.0.4. *Important*: MySQL Cluster NDB 7.0.4 is the successor to MySQL Cluster NDB 6.4.3. Users running MySQL Cluster NDB 6.4.3 should upgrade to MySQL Cluster NDB 7.0.4 or a later 7.0.x release. Obtaining MySQL Cluster NDB 7.0.4 MySQL Cluster NDB 7.0.4 is a source-only release. You can obtain the source code from `ftp://ftp.mysql.com/pub/mysql/download/cluster_telco/mysql-5.1.32-ndb-7.0.4/'. This Beta release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.1, 6.2, 6.3, and 6.4 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.32 (see *Note news-5-1-32::). *Note*: This Beta release, as any other pre-production release, should not be installed on _production_ level systems or systems with critical data. Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * *Important Change*: The default values for a number of MySQL Cluster configuration parameters relating to memory usage and buffering have changed. These parameters include `RedoBuffer', `LongMessageBuffer', `BackupMemory', `BackupDataBufferSize', `BackupLogBufferSize', `BackupWriteSize', `BackupMaxWriteSize', `SendBufferMemory' (when applied to TCP transporters), and `ReceiveBufferMemory'. For more information, see *Note mysql-cluster-configuration::. * When restoring from backup, *Note `ndb_restore': mysql-cluster-programs-ndb-restore. now reports the last global checkpoint reached when the backup was taken. (Bug #37384) *Bugs fixed:* * *Cluster API*: Partition pruning did not work correctly for queries involving multiple range scans. As part of the fix for this issue, several improvements have been made in the NDB API, including the addition of a new `NdbScanOperation::getPruned()' method, a new variant of `NdbIndexScanOperation::setBound()', and a new `PartitionSpec' data structure. (Bug #37934) * `TimeBetweenLocalCheckpoints' was measured from the end of one local checkpoint to the beginning of the next, rather than from the beginning of one LCP to the beginning of the next. This meant that the time spent performing the LCP was not taken into account when determining the `TimeBetweenLocalCheckpoints' interval, so that LCPs were not started often enough, possibly causing data nodes to run out of redo log space prematurely. (Bug #43567) * The management server failed to start correctly in daemon mode. (Bug #43559) * Following a `DROP NODEGROUP' command, the output of `SHOW' in the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. cliently was not updated to reflect the fact that the data nodes affected by this command were no longer part of a node group. (Bug #43413) * Using indexes containing variable-sized columns could lead to internal errors when the indexes were being built. (Bug #43226) * When using *Note `ndbmtd': mysql-cluster-programs-ndbmtd, multiple data node failures caused the remaining data nodes to fail as well. (Bug #43109) * It was not possible to add new data nodes to the cluster online using multi-threaded data node processes (*Note `ndbmtd': mysql-cluster-programs-ndbmtd.). (Bug #43108) * Some queries using combinations of logical and comparison operators on an indexed column in the `WHERE' clause could fail with the error `Got error 4541 'IndexBound has no bound information' from NDBCLUSTER'. (Bug #42857) * *Disk Data*: When using multi-threaded data nodes, dropping a Disk Data table followed by a data node restart led to a crash. (Bug #43632) * *Disk Data*: When using *Note `ndbmtd': mysql-cluster-programs-ndbmtd, repeated high-volume inserts (on the order of 10000 rows inserted at a time) on a Disk Data table would eventually lead to a data node crash. (Bug #41398) * *Disk Data*: When a log file group had an undo log file whose size was too small, restarting data nodes failed with `Read underflow' errors. As a result of this fix, the minimum permitted `INTIAL_SIZE' for an undo log file is now `1M' (1 megabyte). (Bug #29574) * *Cluster API*: The default `NdbRecord' structures created by `NdbDictionary' could have overlapping null bits and data fields. (Bug #43590) * *Cluster API*: When performing insert or write operations, `NdbRecord' permits key columns to be specified in both the key record and in the attribute record. Only one key column value for each key column should be sent to the NDB kernel, but this was not guaranteed. This is now ensured as follows: For insert and write operations, key column values are taken from the key record; for scan takeover update operations, key column values are taken from the attribute record. (Bug #42238) * *Cluster API*: Ordered index scans using `NdbRecord' formerly expressed a `BoundEQ' range as separate lower and upper bounds, resulting in 2 copies of the column values being sent to the NDB kernel. Now, when a range is specified by `NdbScanOperation::setBound()', the passed pointers, key lengths, and inclusive bits are compared, and only one copy of the equal key columns is sent to the kernel. This makes such operations more efficient, as half the amount of `KeyInfo' is now sent for a `BoundEQ' range as before. (Bug #38793)  File: manual.info, Node: mysql-cluster-news-5-1-32-ndb-6-4-3, Next: mysql-cluster-news-5-1-31-ndb-6-4-2, Prev: mysql-cluster-news-5-1-32-ndb-7-0-4, Up: mysql-cluster-news-7-0 17.7.3.35 Changes in MySQL Cluster NDB 6.4.3 (5.1.32-ndb-6.4.3) (23 February 2009) .................................................................................. This is a new Beta development release, incorporating new features in the *Note `NDBCLUSTER': mysql-cluster. storage engine and fixing recently discovered bugs in MySQL Cluster NDB 6.4.2. *Important*: The successor version to MySQL Cluster NDB 6.4.3 is MySQL Cluster NDB 7.0.4. See *Note mysql-cluster-news-5-1-32-ndb-7-0-4::. Obtaining MySQL Cluster NDB 6.4.3 MySQL Cluster NDB 6.4.3 is a source-only release. You can obtain the source code from `ftp://ftp.mysql.com/pub/mysql/download/cluster_telco/mysql-5.1.32-ndb-6.4.3/'. This Beta release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.1, 6.2, 6.3, and 6.4 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.32 (see *Note news-5-1-32::). *Note*: This Beta release, as any other pre-production release, should not be installed on _production_ level systems or systems with critical data. Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * *Important Change*: *Replication*: *Note `RESET MASTER': reset-master. and *Note `RESET SLAVE': reset-slave. now reset the values shown for `Last_IO_Error', `Last_IO_Errno', `Last_SQL_Error', and `Last_SQL_Errno' in the output of *Note `SHOW SLAVE STATUS': show-slave-status. (Bug #34654) See also Bug #44270. * A new data node configuration parameter `MaxLCPStartDelay' has been introduced to facilitate parallel node recovery by causing a local checkpoint to be delayed while recovering nodes are synchronizing data dictionaries and other meta-information. For more information about this parameter, see *Note mysql-cluster-ndbd-definition::. (Bug #43053) * New options are introduced for *Note `ndb_restore': mysql-cluster-programs-ndb-restore. for determining which tables or databases should be restored: * `--include-tables' and `--include-databases' can be used to restore specific tables or databases. * `--exclude-tables' and `--exclude-databases' can be used to exclude the specified tables or databases from being restored. For more information about these options, see *Note mysql-cluster-programs-ndb-restore::. (Bug #40429) * *Disk Data*: It is now possible to specify default locations for Disk Data data files and undo log files, either together or separately, using the data node configuration parameters `FileSystemPathDD', `FileSystemPathDataFiles', and `FileSystemPathUndoFiles'. For information about these configuration parameters, see `Disk Data file system parameters'. It is also now possible to specify a log file group, tablespace, or both, that is created when the cluster is started, using the `InitialLogFileGroup' and `InitialTablespace' data node configuration parameters. For information about these configuration parameters, see `Disk Data object creation parameters'. *Bugs fixed:* * *Performance*: Updates of the `SYSTAB_0' system table to obtain a unique identifier did not use transaction hints for tables having no primary key. In such cases the NDB kernel used a cache size of 1. This meant that each insert into a table not having a primary key required an update of the corresponding `SYSTAB_0' entry, creating a potential performance bottleneck. With this fix, inserts on `NDB' tables without primary keys can be under some conditions be performed up to 100% faster than previously. (Bug #39268) * *Important Note*: It is not possible in this release to install the *Note `InnoDB': innodb-storage-engine. plugin if *Note `InnoDB': innodb-storage-engine. support has been compiled into *Note `mysqld': mysqld. (Bug #42610) This regression was introduced by Bug #29263. * *Packaging*: Packages for MySQL Cluster were missing the `libndbclient.so' and `libndbclient.a' files. (Bug #42278) * *Partitioning*: Executing `ALTER TABLE ... REORGANIZE PARTITION' on an *Note `NDBCLUSTER': mysql-cluster. table having only one partition caused *Note `mysqld': mysqld. to crash. (Bug #41945) See also Bug #40389. * Backup IDs greater than 2^31 were not handled correctly, causing negative values to be used in backup directory names and printouts. (Bug #43042) * When using *Note `ndbmtd': mysql-cluster-programs-ndbmtd, NDB kernel threads could hang while trying to start the data nodes with `LockPagesInMainMemory' set to 1. (Bug #43021) * When using multiple management servers and starting several API nodes (possibly including one or more SQL nodes) whose connectstrings listed the management servers in different order, it was possible for 2 API nodes to be assigned the same node ID. When this happened it was possible for an API node not to get fully connected, consequently producing a number of errors whose cause was not easily recognizable. (Bug #42973) * When using multi-threaded data nodes, `IndexMemory', `MaxNoOfLocalOperations', and `MaxNoOfLocalScans' were effectively multiplied by the number of local query handlers in use by each *Note `ndbmtd': mysql-cluster-programs-ndbmtd. instance. (Bug #42765) See also Bug #42215. * *Note `ndb_error_reporter': mysql-cluster-programs-ndb-error-reporter. worked correctly only with GNU `tar'. (With other versions of `tar', it produced empty archives.) (Bug #42753) * Triggers on *Note `NDBCLUSTER': mysql-cluster. tables caused such tables to become locked. (Bug #42751) See also Bug #16229, Bug #18135. * When performing more than 32 index or tuple scans on a single fragment, the scans could be left hanging. This caused unnecessary timeouts, and in addition could possibly lead to a hang of an LCP. (Bug #42559) * A data node failure that occurred between calls to `NdbIndexScanOperation::readTuples(SF_OrderBy)' and `NdbTransaction::execute()' was not correctly handled; a subsequent call to `nextResult()' caused a null pointer to be deferenced, leading to a segfault in *Note `mysqld': mysqld. (Bug #42545) * If the cluster configuration cache file was larger than 32K, the management server would not start. (Bug #42543) * Issuing `SHOW GLOBAL STATUS LIKE 'NDB%'' before *Note `mysqld': mysqld. had connected to the cluster caused a segmentation fault. (Bug #42458) * When using *Note `ndbmtd': mysql-cluster-programs-ndbmtd. for all data nodes, repeated failures of one data node during DML operations caused other data nodes to fail. (Bug #42450) * Data node failures that occurred before all data nodes had connected to the cluster were not handled correctly, leading to additional data node failures. (Bug #42422) * When using multi-threaded data nodes, their `DataMemory' and `IndexMemory' usage as reported was multiplied by the number of local query handlers (worker threads), making it appear that much more memory was being used than was actually the case. (Bug #42215) See also Bug #42765. * Given a MySQL Cluster containing no data (that is, whose data nodes had all been started using `--initial', and into which no data had yet been imported) and having an empty backup directory, executing `START BACKUP' with a user-specified backup ID caused the data nodes to crash. (Bug #41031) * In some cases, *Note `NDB': mysql-cluster. did not check correctly whether tables had changed before trying to use the query cache. This could result in a crash of the debug MySQL server. (Bug #40464) * *Disk Data*: It was not possible to add an in-memory column online to a table that used a table-level or column-level `STORAGE DISK' option. The same issue prevented `ALTER ONLINE TABLE ... REORGANIZE PARTITION' from working on Disk Data tables. (Bug #42549) * *Disk Data*: Repeated insert and delete operations on disk-based tables could lead to failures in the NDB Tablespace Manager (`TSMAN' kernel block). (Bug #40344) * *Disk Data*: Creating a Disk Data tablespace with a very large extent size caused the data nodes to fail. The issue was observed when using extent sizes of 100 MB and larger. (Bug #39096) * *Disk Data*: Trying to execute a *Note `CREATE LOGFILE GROUP': create-logfile-group. statement using a value greater than `150M' for `UNDO_BUFFER_SIZE' caused data nodes to crash. As a result of this fix, the upper limit for `UNDO_BUFFER_SIZE' is now `600M'; attempting to set a higher value now fails gracefully with an error. (Bug #34102) See also Bug #36702. * *Disk Data*: When attempting to create a tablespace that already existed, the error message returned was `Table or index with given name already exists'. (Bug #32662) * *Disk Data*: Using a path or filename longer than 128 characters for Disk Data undo log files and tablespace data files caused a number of issues, including failures of *Note `CREATE LOGFILE GROUP': create-logfile-group, *Note `ALTER LOGFILE GROUP': alter-logfile-group, *Note `CREATE TABLESPACE': create-tablespace, and *Note `ALTER TABLESPACE': alter-tablespace. statements, as well as crashes of management nodes and data nodes. With this fix, the maximum length for path and file names used for Disk Data undo log files and tablespace data files is now the same as the maximum for the operating system. (Bug #31769, Bug #31770, Bug #31772) * *Disk Data*: Attempting to perform a system restart of the cluster where there existed a logfile group without and undo log files caused the data nodes to crash. *Note*: While issuing a *Note `CREATE LOGFILE GROUP': create-logfile-group. statement without an `ADD UNDOFILE' option fails with an error in the MySQL server, this situation could arise if an SQL node failed during the execution of a valid *Note `CREATE LOGFILE GROUP': create-logfile-group. statement; it is also possible to create a logfile group without any undo log files using the NDB API. (Bug #17614) * *Cluster Replication*: Being disconnected from the cluster while setting up the binary log caused *Note `mysqld': mysqld. to hang or crash. (Bug #43045) * *Cluster Replication*: Primary key updates on *Note `MyISAM': myisam-storage-engine. and *Note `InnoDB': innodb-storage-engine. tables failed to replicate to *Note `NDBCLUSTER': mysql-cluster. tables. (Bug #42921) * *Cluster API*: Some error messages from *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. contained newline (`\n') characters. This could break the MGM API protocol, which uses the newline as a line separator. (Bug #43104) * *Cluster API*: When using an ordered index scan without putting all key columns in the read mask, this invalid use of the NDB API went undetected, which resulted in the use of uninitialized memory. (Bug #42591)  File: manual.info, Node: mysql-cluster-news-5-1-31-ndb-6-4-2, Next: mysql-cluster-news-5-1-31-ndb-6-4-1, Prev: mysql-cluster-news-5-1-32-ndb-6-4-3, Up: mysql-cluster-news-7-0 17.7.3.36 Changes in MySQL Cluster NDB 6.4.2 (5.1.31-ndb-6.4.2) (28 January 2009) ................................................................................. This is a new Beta development release, incorporating new features in the *Note `NDBCLUSTER': mysql-cluster. storage engine and fixing recently discovered bugs in MySQL Cluster NDB 6.4.1. Obtaining MySQL Cluster NDB 6.4.2 MySQL Cluster NDB 6.4.2 is a source-only release. You can obtain the source code from `ftp://ftp.mysql.com/pub/mysql/download/cluster_telco/mysql-5.1.31-ndb-6.4.2/'. This Beta release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.1, 6.2, 6.3, and 6.4 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.31 (see *Note news-5-1-31::). *Note*: This Beta release, as any other pre-production release, should not be installed on _production_ level systems or systems with critical data. Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Bugs fixed:* * Connections using IPv6 were not handled correctly by *Note `mysqld': mysqld. (Bug #42413) See also Bug #42412, Bug #38247. * When a cluster backup failed with Error 1304 (Node NODE_ID1: Backup request from NODE_ID2 failed to start), no clear reason for the failure was provided. As part of this fix, MySQL Cluster now retries backups in the event of sequence errors. (Bug #42354) See also Bug #22698. * Issuing *Note `SHOW ENGINE NDBCLUSTER STATUS': show-engine. on an SQL node before the management server had connected to the cluster caused *Note `mysqld': mysqld. to crash. (Bug #42264) * When using *Note `ndbmtd': mysql-cluster-programs-ndbmtd, setting `MaxNoOfExecutionThreads' to a value higher than the actual number of cores available and with insufficient `SharedGlobalMemory' caused the data nodes to crash. The fix for this issue changes the behavior of *Note `ndbmtd': mysql-cluster-programs-ndbmtd. such that its internal job buffers no longer rely on `SharedGlobalMemory'. (Bug #42254)  File: manual.info, Node: mysql-cluster-news-5-1-31-ndb-6-4-1, Next: mysql-cluster-news-5-1-30-ndb-6-4-0, Prev: mysql-cluster-news-5-1-31-ndb-6-4-2, Up: mysql-cluster-news-7-0 17.7.3.37 Changes in MySQL Cluster NDB 6.4.1 (5.1.31-ndb-6.4.1) (21 January 2009) ................................................................................. This is a new Beta development release, incorporating new features in the *Note `NDBCLUSTER': mysql-cluster. storage engine and fixing recently discovered bugs in MySQL Cluster NDB 6.4.0. Obtaining MySQL Cluster NDB 6.4.1 MySQL Cluster NDB 6.4.1 is a source-only release. You can obtain the source code from `ftp://ftp.mysql.com/pub/mysql/download/cluster_telco/mysql-5.1.31-ndb-6.4.1/'. This Beta release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.1, 6.2, 6.3, and 6.4 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.31 (see *Note news-5-1-31::). *Note*: This Beta release, as any other pre-production release, should not be installed on _production_ level systems or systems with critical data. Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * *Important Change*: Formerly, when the management server failed to create a transporter for a data node connection, `net_write_timeout' seconds elapsed before the data node was actually permitted to disconnect. Now in such cases the disconnection occurs immediately. (Bug #41965) See also Bug #41713. * Formerly, when using MySQL Cluster Replication, records for `empty' epochs--that is, epochs in which no changes to *Note `NDBCLUSTER': mysql-cluster. data or tables took place--were inserted into the `ndb_apply_status' and `ndb_binlog_index' tables on the slave even when `--log-slave-updates' was disabled. Beginning with MySQL Cluster NDB 6.2.16 and MySQL Cluster NDB 6.3.13 this was changed so that these `empty' eopchs were no longer logged. However, it is now possible to re-enable the older behavior (and cause `empty' epochs to be logged) by using the `--ndb-log-empty-epochs' option. For more information, see *Note replication-options-slave::. See also Bug #37472. * *Cluster Replication*: IPv6 networking is now supported between MySQL Cluster SQL nodes. This means that it is now possible to replicate between instances of MySQL Cluster using IPv6 addresses. *Important*: Currently, other MySQL Cluster processes (*Note `ndbd': mysql-cluster-programs-ndbd, *Note `ndbmtd': mysql-cluster-programs-ndbmtd, *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd, and *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm.) do not support IPv6 connections. This means that all MySQL Cluster data nodes, management servers, and management clients must connect to and be accessible from one another using IPv4. In addition, SQL nodes must use IPv4 to communicate with the cluster. There is also not yet any support in the NDB and MGM APIs for IPv6, which means that applications written using the MySQL Cluster APIs must make connections using IPv4. For more information, see *Note mysql-cluster-replication-issues::. *Bugs fixed:* * A maximum of 11 `TUP' scans were permitted in parallel. (Bug #42084) * The management server could hang after attempting to halt it with the `STOP' command in the management client. (Bug #42056) See also Bug #40922. * When using *Note `ndbmtd': mysql-cluster-programs-ndbmtd, one thread could flood another thread, which would cause the system to stop with a `job buffer full' condition (currently implemented as an abort). This could be caused by committing or aborting a large transaction (50000 rows or more) on a single data node running *Note `ndbmtd': mysql-cluster-programs-ndbmtd. To prevent this from happening, the number of signals that can be accepted by the system threads is calculated before excuting them, and only executing them if sufficient space is found. (Bug #42052) * MySQL Cluster would not compile when using `libwrap'. This issue was known to occur only in MySQL Cluster NDB 6.4.0. (Bug #41918) * Trying to execute an *Note `ALTER ONLINE TABLE ... ADD COLUMN': alter-table. statement while inserting rows into the table caused *Note `mysqld': mysqld. to crash. (Bug #41905) * When a data node connects to the management server, the node sends its node ID and transporter type; the management server then verifies that there is a transporter set up for that node and that it is in the correct state, and then sends back an acknowledgment to the connecting node. If the transporter was not in the correct state, no reply was sent back to the connecting node, which would then hang until a read timeout occurred (60 seconds). Now, if the transporter is not in the correct state, the management server acknowledges this promptly, and the node immediately disconnects. (Bug #41713) See also Bug #41965. * Issuing `EXIT' in the management client sometimes caused the client to hang. (Bug #40922) * In the event that a MySQL Cluster backup failed due to file permissions issues, conflicting reports were issued in the management client. (Bug #34526) * If all data nodes were shut down, MySQL clients were unable to access *Note `NDBCLUSTER': mysql-cluster. tables and data even after the data nodes were restarted, unless the MySQL clients themselves were restarted. (Bug #33626)  File: manual.info, Node: mysql-cluster-news-5-1-30-ndb-6-4-0, Prev: mysql-cluster-news-5-1-31-ndb-6-4-1, Up: mysql-cluster-news-7-0 17.7.3.38 Changes in MySQL Cluster NDB 6.4.0 (5.1.30-ndb-6.4.0) (22 December 2008 Beta) ....................................................................................... This is a new Beta development release, incorporating new features in the *Note `NDBCLUSTER': mysql-cluster. storage engine and fixing recently discovered bugs in previous MySQL Cluster releases. Obtaining MySQL Cluster NDB 6.4.0 MySQL Cluster NDB 6.4.0 is a source-only release. You can obtain the source code from `ftp://ftp.mysql.com/pub/mysql/download/cluster_telco/mysql-5.1.30-ndb-6.4.0/'. This Beta release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.1, 6.2, and 6.3 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.30 (see *Note news-5-1-30::). *Note*: This Beta release, as any other pre-production release, should not be installed on _production_ level systems or systems with critical data. Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * *Important Change*: MySQL Cluster now caches its configuration data. This means that, by default, the management server only reads the global configuration file (usually named `config.ini') the first time that it is started, and does not automatically re-read the this file when restarted. This behavior can be controlled using new management server options (`--config-dir', `--initial', and `--reload') that have been added for this purpose. For more information, see *Note mysql-cluster-config-file::, and *Note mysql-cluster-programs-ndb-mgmd::. * It is now possible while in Single User Mode to restart all data nodes using `ALL RESTART' in the management client. Restarting of individual nodes while in Single User Mode remains not permitted. (Bug #31056) * It is now possible to add data nodes to a MySQL Cluster online--that is, to a running MySQL Cluster without shutting it down. For information about the procedure for adding data nodes online, see *Note mysql-cluster-online-add-node::. * A multi-threaded version of the MySQL Cluster data node daemon is now available. The multi-threaded *Note `ndbmtd': mysql-cluster-programs-ndbmtd. binary is similar to *Note `ndbd': mysql-cluster-programs-ndbd. and functions in much the same way, but is intended for use on machines with multiple CPU cores. For more information, see *Note mysql-cluster-programs-ndbmtd::. * It is now possible when performing a cluster backup to determine whether the backup matches the state of the data when the backup began or when it ended, using the new `START BACKUP' options `SNAPSHOTSTART' and `SNAPSHOTEND' in the management client. See *Note mysql-cluster-backup-using-management-client::, for more information. * *Cluster API*: Two new `Ndb_cluster_connection' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndb-cluster-connection.html#ndb-ndb-cluster-connection) methods have been added to help in diagnosing problems with NDB API client connections. The `get_latest_error()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndb-cluster-connection-methods.html#ndb-ndb-cluster-connection-get-latest-error) method tells whether or not the latest connection attempt succeeded; if the attempt failed, `get_latest_error_msg()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndb-cluster-connection-methods.html#ndb-ndb-cluster-connection-get-latest-error-msg) provides an error message giving the reason. *Bugs fixed:* * API nodes disconnected too agressively from cluster when data nodes were being restarted. This could sometimes lead to the API node being unable to access the cluster at all during a rolling restart. (Bug #41462) * When long signal buffer exhaustion in the *Note `ndbd': mysql-cluster-programs-ndbd. process resulted in a signal being dropped, the usual handling mechanism did not take fragmented signals into account. This could result in a crash of the data node because the fragmented signal handling mechanism was not able to work with the missing fragments. (Bug #39235) * The failure of a master node during a DDL operation caused the cluster to be unavailable for further DDL operations until it was restarted; failures of nonmaster nodes during DLL operations caused the cluster to become completely inaccessible. (Bug #36718) * Status messages shown in the management client when restarting a management node were inappropriate and misleading. Now, when restarting a management node, the messages displayed are as follows, where NODE_ID is the management node's node ID: ndb_mgm> NODE_ID RESTART Shutting down MGM node NODE_ID for restart Node NODE_ID is being restarted ndb_mgm> (Bug #29275) * A data node failure when `NoOfReplicas' was greater than 2 caused all cluster SQL nodes to crash. (Bug #18621) * *Partitioning*: A query on a user-partitioned table caused MySQL to crash, where the query had the following characteristics: * The query's `WHERE' clause referenced an indexed column that was also in the partitioning key. * The query's `WHERE' clause included a value found in the partition. * The query's `WHERE' clause used the `<' or `<>' operators to compare with the indexed column's value with a constant. * The query used an `ORDER BY' clause, and the same indexed column was used in the `ORDER BY' clause. * The `ORDER BY' clause used an explcit or implicit `ASC' sort priority. Two examples of such a query are given here, where `a' represents an indexed column used in the table's partitioning key: 1. SELECT * FROM TABLE WHERE a < CONSTANT ORDER BY a; 2. SELECT * FROM TABLE WHERE a <> CONSTANT ORDER BY a; (Bug #40954) This regression was introduced by Bug #30573, Bug #33257, Bug #33555.  File: manual.info, Node: mysql-cluster-news-6-3, Next: mysql-cluster-news-6-2, Prev: mysql-cluster-news-7-0, Up: mysql-cluster-news 17.7.4 Changes in MySQL Cluster NDB 6.3 --------------------------------------- * Menu: * mysql-cluster-news-5-1-56-ndb-6-3-45:: Changes in MySQL Cluster NDB 6.3.45 (5.1.56-ndb-6.3.45) (Not yet released) * mysql-cluster-news-5-1-56-ndb-6-3-44:: Changes in MySQL Cluster NDB 6.3.44 (5.1.56-ndb-6.3.44) (19 May 2011) * mysql-cluster-news-5-1-56-ndb-6-3-43:: Changes in MySQL Cluster NDB 6.3.43 (5.1.56-ndb-6.3.43) (26 April 2011) * mysql-cluster-news-5-1-51-ndb-6-3-42:: Changes in MySQL Cluster NDB 6.3.42 (5.1.51-ndb-6.3.42) (04 April 2011) * mysql-cluster-news-5-1-51-ndb-6-3-41:: Changes in MySQL Cluster NDB 6.3.41 (5.1.51-ndb-6.3.41) (25 February 2011) * mysql-cluster-news-5-1-51-ndb-6-3-40:: Changes in MySQL Cluster NDB 6.3.40 (5.1.51-ndb-6.3.40) (26 January 2011) * mysql-cluster-news-5-1-51-ndb-6-3-39:: Changes in MySQL Cluster NDB 6.3.39 (5.1.51-ndb-6.3.39) (08 November 2010) * mysql-cluster-news-5-1-47-ndb-6-3-38:: Changes in MySQL Cluster NDB 6.3.38 (5.1.47-ndb-6.3.38) (08 October 2010) * mysql-cluster-news-5-1-47-ndb-6-3-37:: Changes in MySQL Cluster NDB 6.3.37 (5.1.47-ndb-6.3.37) (03 September 2010) * mysql-cluster-news-5-1-47-ndb-6-3-36:: Changes in MySQL Cluster NDB 6.3.36 (5.1.47-ndb-6.3.36) (16 August 2010) * mysql-cluster-news-5-1-47-ndb-6-3-35:: Changes in MySQL Cluster NDB 6.3.35 (5.1.47-ndb-6.3.35) (25 June 2010) * mysql-cluster-news-5-1-44-ndb-6-3-34:: Changes in MySQL Cluster NDB 6.3.34 (5.1.44-ndb-6.3.34) (31 May 2010) * mysql-cluster-news-5-1-44-ndb-6-3-33:: Changes in MySQL Cluster NDB 6.3.33 (5.1.44-ndb-6.3.33) (31 March 2010) * mysql-cluster-news-5-1-41-ndb-6-3-32:: Changes in MySQL Cluster NDB 6.3.32 (5.1.41-ndb-6.3.32) (04 March 2010) * mysql-cluster-news-5-1-41-ndb-6-3-31b:: Changes in MySQL Cluster NDB 6.3.31b (5.1.41-ndb-6.3.31b) (18 February 2010) * mysql-cluster-news-5-1-41-ndb-6-3-31a:: Changes in MySQL Cluster NDB 6.3.31a (5.1.41-ndb-6.3.31a) (15 February 2010) * mysql-cluster-news-5-1-41-ndb-6-3-31:: Changes in MySQL Cluster NDB 6.3.31 (5.1.41-ndb-6.3.31) (02 February 2010) * mysql-cluster-news-5-1-39-ndb-6-3-30:: Changes in MySQL Cluster NDB 6.3.30 (5.1.39-ndb-6.3.30) (15 December 2009) * mysql-cluster-news-5-1-39-ndb-6-3-29:: Changes in MySQL Cluster NDB 6.3.29 (5.1.39-ndb-6.3.29) (15 December 2009) * mysql-cluster-news-5-1-39-ndb-6-3-28b:: Changes in MySQL Cluster NDB 6.3.28b (5.1.39-ndb-6.3.28b) (10 November 2009) * mysql-cluster-news-5-1-39-ndb-6-3-28a:: Changes in MySQL Cluster NDB 6.3.28a (5.1.39-ndb-6.3.28a) (05 November 2009) * mysql-cluster-news-5-1-39-ndb-6-3-28:: Changes in MySQL Cluster NDB 6.3.28 (5.1.39-ndb-6.3.28) (31 October 2009) * mysql-cluster-news-5-1-37-ndb-6-3-27a:: Changes in MySQL Cluster NDB 6.3.27a (5.1.37-ndb-6.3.27a) (07 October 2009) * mysql-cluster-news-5-1-37-ndb-6-3-27:: Changes in MySQL Cluster NDB 6.3.27 (5.1.37-ndb-6.3.27) (30 September 2009) * mysql-cluster-news-5-1-35-ndb-6-3-26:: Changes in MySQL Cluster NDB 6.3.26 (5.1.35-ndb-6.3.26) (26 August 2009) * mysql-cluster-news-5-1-34-ndb-6-3-25:: Changes in MySQL Cluster NDB 6.3.25 (5.1.34-ndb-6.3.25) (25 May 2009) * mysql-cluster-news-5-1-32-ndb-6-3-24:: Changes in MySQL Cluster NDB 6.3.24 (5.1.32-ndb-6.3.24) (09 April 2009) * mysql-cluster-news-5-1-32-ndb-6-3-23:: Changes in MySQL Cluster NDB 6.3.23 (5.1.32-ndb-6.3.23) (24 February 2009) * mysql-cluster-news-5-1-31-ndb-6-3-22:: Changes in MySQL Cluster NDB 6.3.22 (5.1.31-ndb-6.3.22) (09 February 2009) * mysql-cluster-news-5-1-31-ndb-6-3-21:: Changes in MySQL Cluster NDB 6.3.21 (5.1.31-ndb-6.3.21) (19 January 2009) * mysql-cluster-news-5-1-30-ndb-6-3-20:: Changes in MySQL Cluster NDB 6.3.20 (5.1.30-ndb-6.3.20) (17 December 2008) * mysql-cluster-news-5-1-29-ndb-6-3-19:: Changes in MySQL Cluster NDB 6.3.19 (5.1.29-ndb-6.3.19) (21 November 2008) * mysql-cluster-news-5-1-28-ndb-6-3-18:: Changes in MySQL Cluster NDB 6.3.18 (5.1.28-ndb-6.3.18) (03 October 2008) * mysql-cluster-news-5-1-27-ndb-6-3-17:: Changes in MySQL Cluster NDB 6.3.17 (5.1.27-ndb-6.3.17) (28 August 2008) * mysql-cluster-news-5-1-24-ndb-6-3-16:: Changes in MySQL Cluster NDB 6.3.16 (5.1.24-ndb-6.3.16) (27 June 2008) * mysql-cluster-news-5-1-24-ndb-6-3-15:: Changes in MySQL Cluster NDB 6.3.15 (5.1.24-ndb-6.3.15) (30 May 2008) * mysql-cluster-news-5-1-24-ndb-6-3-14:: Changes in MySQL Cluster NDB 6.3.14 (5.1.24-ndb-6.3.14) (11 May 2008) * mysql-cluster-news-5-1-24-ndb-6-3-13:: Changes in MySQL Cluster NDB 6.3.13 (5.1.24-ndb-6.3.13) (10 April 2008) * mysql-cluster-news-5-1-23-ndb-6-3-12:: Changes in MySQL Cluster NDB 6.3.12 (5.1.23-ndb-6.3.12) (05 April 2008) * mysql-cluster-news-5-1-23-ndb-6-3-11:: Changes in MySQL Cluster NDB 6.3.11 (5.1.23-ndb-6.3.11) (28 March 2008) * mysql-cluster-news-5-1-23-ndb-6-3-10:: Changes in MySQL Cluster NDB 6.3.10 (5.1.23-ndb-6.3.10) (17 February 2008) * mysql-cluster-news-5-1-23-ndb-6-3-9:: Changes in MySQL Cluster NDB 6.3.9 (5.1.23-ndb-6.3.9) (12 February 2008) * mysql-cluster-news-5-1-23-ndb-6-3-8:: Changes in MySQL Cluster NDB 6.3.8 (5.1.23-ndb-6.3.8) (29 January 2008 General Availability) * mysql-cluster-news-5-1-23-ndb-6-3-7:: Changes in MySQL Cluster NDB 6.3.7 (5.1.23-ndb-6.3.7) (19 December 2007) * mysql-cluster-news-5-1-22-ndb-6-3-6:: Changes in MySQL Cluster NDB 6.3.6 (5.1.22-ndb-6.3.6) (08 November 2007) * mysql-cluster-news-5-1-22-ndb-6-3-5:: Changes in MySQL Cluster NDB 6.3.5 (5.1.22-ndb-6.3.5) (17 October 2007) * mysql-cluster-news-5-1-22-ndb-6-3-4:: Changes in MySQL Cluster NDB 6.3.4 (5.1.22-ndb-6.3.4) (15 October 2007) * mysql-cluster-news-5-1-22-ndb-6-3-3:: Changes in MySQL Cluster NDB 6.3.3 (5.1.22-ndb-6.3.3) (20 September 2007) * mysql-cluster-news-5-1-22-ndb-6-3-2:: Changes in MySQL Cluster NDB 6.3.2 (5.1.22-ndb-6.3.2) (07 September 2007) * mysql-cluster-news-5-1-19-ndb-6-3-1:: Changes in MySQL Cluster NDB 6.3.1 (5.1.19-ndb-6.3.1) (04 July 2007) * mysql-cluster-news-5-1-19-ndb-6-3-0:: Changes in MySQL Cluster NDB 6.3.0 (5.1.19-ndb-6.3.0) (02 July 2007 Beta) This section contains change history information for MySQL Cluster releases based on version 6.3 of the *Note `NDBCLUSTER': mysql-cluster. storage engine. For an overview of new features added in MySQL Cluster NDB 6.3, see *Note mysql-cluster-development-5-1-ndb-6-3::.  File: manual.info, Node: mysql-cluster-news-5-1-56-ndb-6-3-45, Next: mysql-cluster-news-5-1-56-ndb-6-3-44, Prev: mysql-cluster-news-6-3, Up: mysql-cluster-news-6-3 17.7.4.1 Changes in MySQL Cluster NDB 6.3.45 (5.1.56-ndb-6.3.45) (Not yet released) ................................................................................... This is a bugfix release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.3 release. Obtaining MySQL Cluster NDB 6.3 The latest MySQL Cluster NDB 6.3 binaries for supported platforms can be obtained from `http://dev.mysql.com/downloads/cluster/'. Source code for the latest MySQL Cluster NDB 6.3 release can be obtained from the same location. You can also access the MySQL Cluster NDB 6.3 development source tree at `https://code.launchpad.net/~mysql/mysql-server/mysql-5.1-telco-6.3'. This release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.3 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.56 (see *Note news-5-1-56::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Bugs fixed:* * When global checkpoint indexes were written with no intervening end-of-file or megabyte border markers, this could sometimes lead to a situation in which the end of the redo log was mistakenly regarded as being between these GCIs, so that if the restart of a data node took place before the start of the next redo log was overwritten, the node encountered an `Error while reading the REDO log'. (Bug #12653993, Bug #61500) See also Bug #56961. * Error reporting has been improved for cases in which API nodes are unable to connect due to apparent unavailability of node IDs. (Bug #12598398) * Error messages for `Failed to convert connection' transporter registration problems were inspecific. (Bug #12589691) * Under certain rare circumstances, a data node process could fail with Signal 11 during a restart. This was due to uninitialized variables in the `QMGR' kernel block. (Bug #12586190) * Handling of the `MaxNoOfTables' and `MaxNoOfAttributes' configuration parameters was not consistent in all parts of the *Note `NDB': mysql-cluster. kernel, and were only strictly enforced by the `DBDICT' and `SUMA' kernel blocks. This could lead to problems when tables could be created but not replicated. Now these parameters are treated by `SUMA' and `DBDICT' as suggested maximums rather than hard limits, as they are elsewhere in the *Note `NDB': mysql-cluster. kernel. (Bug #61684) * *Cluster API*: Within a transaction, after creating, executing, and closing a scan, calling `NdbTransaction::refresh()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndbtransaction-methods.html#ndb-ndbtransaction-refresh) after creating and executing but not closing a second scan caused the application to crash. (Bug #12646659)  File: manual.info, Node: mysql-cluster-news-5-1-56-ndb-6-3-44, Next: mysql-cluster-news-5-1-56-ndb-6-3-43, Prev: mysql-cluster-news-5-1-56-ndb-6-3-45, Up: mysql-cluster-news-6-3 17.7.4.2 Changes in MySQL Cluster NDB 6.3.44 (5.1.56-ndb-6.3.44) (19 May 2011) .............................................................................. This is a bugfix release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.3 release. Obtaining MySQL Cluster NDB 6.3 The latest MySQL Cluster NDB 6.3 binaries for supported platforms can be obtained from `http://dev.mysql.com/downloads/cluster/'. Source code for the latest MySQL Cluster NDB 6.3 release can be obtained from the same location. You can also access the MySQL Cluster NDB 6.3 development source tree at `https://code.launchpad.net/~mysql/mysql-server/mysql-5.1-telco-6.3'. This release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.3 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.56 (see *Note news-5-1-56::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Bugs fixed:* * Two unused test files in `storage/ndb/test/sql' contained incorrect versions of the GNU Lesser General Public License. The files and the directory containing them have been removed. (Bug #11810156) See also Bug #11810224.  File: manual.info, Node: mysql-cluster-news-5-1-56-ndb-6-3-43, Next: mysql-cluster-news-5-1-51-ndb-6-3-42, Prev: mysql-cluster-news-5-1-56-ndb-6-3-44, Up: mysql-cluster-news-6-3 17.7.4.3 Changes in MySQL Cluster NDB 6.3.43 (5.1.56-ndb-6.3.43) (26 April 2011) ................................................................................ This is a bugfix release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.3 release. Obtaining MySQL Cluster NDB 6.3 The latest MySQL Cluster NDB 6.3 binaries for supported platforms can be obtained from `http://dev.mysql.com/downloads/cluster/'. Source code for the latest MySQL Cluster NDB 6.3 release can be obtained from the same location. You can also access the MySQL Cluster NDB 6.3 development source tree at `https://code.launchpad.net/~mysql/mysql-server/mysql-5.1-telco-6.3'. This release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.3 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.56 (see *Note news-5-1-56::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Bugs fixed:* * *Cluster API*: Performing interpreted operations using a unique index did not work correctly, because the interpret bit was kept when sending the lookup to the index table.  File: manual.info, Node: mysql-cluster-news-5-1-51-ndb-6-3-42, Next: mysql-cluster-news-5-1-51-ndb-6-3-41, Prev: mysql-cluster-news-5-1-56-ndb-6-3-43, Up: mysql-cluster-news-6-3 17.7.4.4 Changes in MySQL Cluster NDB 6.3.42 (5.1.51-ndb-6.3.42) (04 April 2011) ................................................................................ This is a bugfix release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.3 release. Obtaining MySQL Cluster NDB 6.3 The latest MySQL Cluster NDB 6.3 binaries for supported platforms can be obtained from `http://dev.mysql.com/downloads/cluster/'. Source code for the latest MySQL Cluster NDB 6.3 release can be obtained from the same location. You can also access the MySQL Cluster NDB 6.3 development source tree at `https://code.launchpad.net/~mysql/mysql-server/mysql-5.1-telco-6.3'. This release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.3 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.51 (see *Note news-5-1-51::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Bugs fixed:* * A scan with a pushed condition (filter) using the `CommittedRead' lock mode could hang for a short interval when it was aborted when just as it had decided to send a batch. (Bug #11932525) * When aborting a multi-read range scan exactly as it was changing ranges in the local query handler, LQH could fail to detect it, leaving the scan hanging. (Bug #11929643) * *Replication*: Error 1590 (`ER_SLAVE_INCIDENT') caused the slave to stop even when it was started with `--slave-skip-errors=1590'. (Bug #59889, Bug #11768580, Bug #11799671) * *Cluster Replication*: Filtering the binary log using `--binlog-ignore-db=mysql' caused epochs not to be logged as expected in the `ndb_apply_status' table. (Bug #11765707, Bug #58698) * *Disk Data*: Limits imposed by the size of `SharedGlobalMemory' were not always enforced consistently with regard to Disk Data undo buffers and log files. This could sometimes cause a *Note `CREATE LOGFILE GROUP': create-logfile-group. or *Note `ALTER LOGFILE GROUP': alter-logfile-group. statement to fail for no apparent reason, or cause the log file group specified by `InitialLogFileGroup' not to be created when starting the cluster. (Bug #57317)  File: manual.info, Node: mysql-cluster-news-5-1-51-ndb-6-3-41, Next: mysql-cluster-news-5-1-51-ndb-6-3-40, Prev: mysql-cluster-news-5-1-51-ndb-6-3-42, Up: mysql-cluster-news-6-3 17.7.4.5 Changes in MySQL Cluster NDB 6.3.41 (5.1.51-ndb-6.3.41) (25 February 2011) ................................................................................... This is a bugfix release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.3 release. Obtaining MySQL Cluster NDB 6.3 The latest MySQL Cluster NDB 6.3 binaries for supported platforms can be obtained from `http://dev.mysql.com/downloads/cluster/'. Source code for the latest MySQL Cluster NDB 6.3 release can be obtained from the same location. You can also access the MySQL Cluster NDB 6.3 development source tree at `https://code.launchpad.net/~mysql/mysql-server/mysql-5.1-telco-6.3'. This release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.3 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.51 (see *Note news-5-1-51::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * A new `--rewrite-database' option is added for *Note `ndb_restore': mysql-cluster-programs-ndb-restore, which makes it possible to restore to a database having a different name from that of the database in the backup. For more information, see *Note mysql-cluster-programs-ndb-restore::. (Bug #54327)  File: manual.info, Node: mysql-cluster-news-5-1-51-ndb-6-3-40, Next: mysql-cluster-news-5-1-51-ndb-6-3-39, Prev: mysql-cluster-news-5-1-51-ndb-6-3-41, Up: mysql-cluster-news-6-3 17.7.4.6 Changes in MySQL Cluster NDB 6.3.40 (5.1.51-ndb-6.3.40) (26 January 2011) .................................................................................. This is a bugfix release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.3 release. Obtaining MySQL Cluster NDB 6.3 The latest MySQL Cluster NDB 6.3 binaries for supported platforms can be obtained from `http://dev.mysql.com/downloads/cluster/'. Source code for the latest MySQL Cluster NDB 6.3 release can be obtained from the same location. You can also access the MySQL Cluster NDB 6.3 development source tree at `https://code.launchpad.net/~mysql/mysql-server/mysql-5.1-telco-6.3'. This release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.3 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.51 (see *Note news-5-1-51::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * Added the `--skip-broken-objects' option for *Note `ndb_restore': mysql-cluster-programs-ndb-restore. This option causes *Note `ndb_restore': mysql-cluster-programs-ndb-restore. to ignore tables corrupted due to missing blob parts tables, and to continue reading from the backup file and restoring the remaining tables. (Bug #54613) See also Bug #51652. *Bugs fixed:* * Two related problems could occur with read-committed scans made in parallel with transactions combining multiple (concurrent) operations: 1. When committing a multiple-operation transaction that contained concurrent insert and update operations on the same record, the commit arrived first for the insert and then for the update. If a read-committed scan arrived between these operations, it could thus read incorrect data; in addition, if the scan read variable-size data, it could cause the data node to fail. 2. When rolling back a multiple-operation transaction having concurrent delete and insert operations on the same record, the abort arrived first for the delete operation, and then for the insert. If a read-committed scan arrived between the delete and the insert, it could incorrectly assume that the record should not be returned (in other words, the scan treated the insert as though it had not yet been committed). (Bug #59496) * A row insert or update followed by a delete operation on the same row within the same transaction could in some cases lead to a buffer overflow. (Bug #59242) See also Bug #56524. This regression was introduced by Bug #35208. * The `FAIL_REP' signal, used inside the NDB kernel to declare that a node has failed, now includes the node ID of the node that detected the failure. This information can be useful in debugging. (Bug #58904) * Issuing *Note `EXPLAIN EXTENDED': explain. for a query that would use condition pushdown could cause *Note `mysqld': mysqld. to crash. (Bug #58553, Bug #11765570) * In some circumstances, an SQL trigger on an *Note `NDB': mysql-cluster. table could read stale data. (Bug #58538) * During a node takeover, it was possible in some circumstances for one of the remaining nodes to send an extra transaction confirmation (`LQH_TRANSCONF') signal to the `DBTC' kernel block, conceivably leading to a crash of the data node trying to take over as the new transaction coordinator. (Bug #58453) * A query having multiple predicates joined by `OR' in the `WHERE' clause and which used the `sort_union' access method (as shown using *Note `EXPLAIN': explain.) could return duplicate rows. (Bug #58280) * Trying to drop an index while it was being used to perform scan updates caused data nodes to crash. (Bug #58277, Bug #57057) * When handling failures of multiple data nodes, an error in the construction of internal signals could cause the cluster's remaining nodes to crash. This issue was most likely to affect clusters with large numbers of data nodes. (Bug #58240) * Some queries of the form *Note `SELECT ... WHERE COLUMN IN (SUBQUERY)': select. against an *Note `NDB': mysql-cluster. table could cause *Note `mysqld': mysqld. to hang in an endless loop. (Bug #58163) * The number of rows affected by a statement that used a `WHERE' clause having an `IN' condition with a value list containing a great many elements, and that deleted or updated enough rows such that *Note `NDB': mysql-cluster. processed them in batches, was not computed or reported correctly. (Bug #58040) * A query using `BETWEEN' as part of a pushed-down `WHERE' condition could cause mysqld to hang or crash. (Bug #57735) * In some circumstances, it was possible for *Note `mysqld': mysqld. to begin a new multi-range read scan without having closed a previous one. This could lead to exhaustion of all scan operation objects, transaction objects, or lock objects (or some combination of these) in *Note `NDB': mysql-cluster, causing queries to fail with such errors as `Lock wait timeout exceeded' or `Connect failure - out of connection objects'. (Bug #57481) See also Bug #58750. * Queries using `COLUMN IS' [`NOT'] `NULL' on a table with a unique index created with `USING HASH' on COLUMN always returned an empty result. (Bug #57032) * With `engine_condition_pushdown' enabled, a query using `LIKE' on an *Note `ENUM': enum. column of an *Note `NDB': mysql-cluster. table failed to return any results. This issue is resolved by disabling `engine_condition_pushdown' when performing such queries. (Bug #53360) * When a slash character (`/') was used as part of the name of an index on an *Note `NDB': mysql-cluster. table, attempting to execute a *Note `TRUNCATE TABLE': truncate-table. statement on the table failed with the error `Index not found', and the table was rendered unusable. (Bug #38914) * *Disk Data*: In certain cases, a race condition could occur when *Note `DROP LOGFILE GROUP': drop-logfile-group. removed the logfile group while a read or write of one of the effected files was in progress, which in turn could lead to a crash of the data node. (Bug #59502) * *Disk Data*: A race condition could sometimes be created when *Note `DROP TABLESPACE': drop-tablespace. was run concurrently with a local checkpoint; this could in turn lead to a crash of the data node. (Bug #59501) * *Disk Data*: Performing what should have been an online drop of a multi-column index was actually performed offline. (Bug #55618) * *Disk Data*: When at least one data node was not running, queries against the *Note `INFORMATION_SCHEMA.FILES': files-table. table took an excessive length of time to complete because the MySQL server waited for responses from any stopped nodes to time out. Now, in such cases, MySQL does not attempt to contact nodes which are not known to be running. (Bug #54199) * *Cluster API*: Attempting to read the same value (using `getValue()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndboperation-methods.html#ndb-ndboperation-getvalue)) more than 9000 times within the same transaction caused the transaction to hang when executed. Now when more reads are performed in this way than can be accommodated in a single transaction, the call to `execute()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndbtransaction-methods.html#ndb-ndbtransaction-execute) fails with a suitable error. (Bug #58110)  File: manual.info, Node: mysql-cluster-news-5-1-51-ndb-6-3-39, Next: mysql-cluster-news-5-1-47-ndb-6-3-38, Prev: mysql-cluster-news-5-1-51-ndb-6-3-40, Up: mysql-cluster-news-6-3 17.7.4.7 Changes in MySQL Cluster NDB 6.3.39 (5.1.51-ndb-6.3.39) (08 November 2010) ................................................................................... This is a bugfix release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.3 release. Obtaining MySQL Cluster NDB 6.3 The latest MySQL Cluster NDB 6.3 binaries for supported platforms can be obtained from `http://dev.mysql.com/downloads/cluster/'. Source code for the latest MySQL Cluster NDB 6.3 release can be obtained from the same location. You can also access the MySQL Cluster NDB 6.3 development source tree at `https://code.launchpad.net/~mysql/mysql-server/mysql-5.1-telco-6.3'. This release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.3 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.51 (see *Note news-5-1-51::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * *Important Change*: The `Id' configuration parameter used with MySQL Cluster management, data, and API nodes (including SQL nodes) is now deprecated, and the `NodeId' parameter (long available as a synonym for `Id' when configuring these types of nodes) should be used instead. `Id' continues to be supported for reasons of backward compatibility, but now generates a warning when used with these types of nodes, and is subject to removal in a future release of MySQL Cluster. This change affects the name of the configuration parameter only, establishing a clear preference for `NodeId' over `Id' in the `[mgmd]', `[ndbd]', `[mysql]', and `[api]' sections of the MySQL Cluster global configuration (`config.ini') file. The behavior of unique identifiers for management, data, and SQL and API nodes in MySQL Cluster has not otherwise been altered. The `Id' parameter as used in the `[computer]' section of the MySQL Cluster global configuration file is not affected by this change. *Bugs fixed:* * *Packaging*: MySQL Cluster RPM distributions did not include a `shared-compat' RPM for the MySQL Server, which meant that MySQL applications depending on `libmysqlclient.so.15' (MySQL 5.0 and earlier) no longer worked. (Bug #38596) * The `LQHKEYREQ' request message used by the local query handler when checking the major schema version of a table, being only 16 bits wide, could cause this check to fail with an `Invalid schema version' error (*Note `NDB': mysql-cluster. error code 1227). This issue occurred after creating and dropping (and re-creating) the same table 65537 times, then trying to insert rows into the table. (Bug #57896) See also Bug #57897. * An internal buffer overrun could cause a data node to fail. (Bug #57767) * Data nodes compiled with `gcc' 4.5 or higher crashed during startup. (Bug #57761) * *Note `ndb_restore': mysql-cluster-programs-ndb-restore. now retries failed transactions when replaying log entries, just as it does when restoring data. (Bug #57618) * During a GCP takeover, it was possible for one of the data nodes not to receive a `SUB_GCP_COMPLETE_REP' signal, with the result that it would report itself as `GCP_COMMITTING' while the other data nodes reported `GCP_PREPARING'. (Bug #57522) * Specifying a *Note `WHERE': select. clause of the form `RANGE1 OR RANGE2' when selecting from an *Note `NDB': mysql-cluster. table having a primary key on multiple columns could result in Error 4259 `Invalid set of range scan bounds' if RANGE2 started exactly where RANGE1 ended and the primary key definition declared the columns in a different order relative to the order in the table's column list. (Such a query should simply return all rows in the table, since any expression `VALUE < CONSTANT OR VALUE >= CONSTANT' is always true.) Example Suppose `t' is an *Note `NDB': mysql-cluster. table defined by the following *Note `CREATE TABLE': create-table. statement: CREATE TABLE t (a, b, PRIMARY KEY (b, a)) ENGINE NDB; This issue could then be triggered by a query such as this one: SELECT * FROM t WHERE b < 8 OR b >= 8; In addition, the order of the ranges in the `WHERE' clause was significant; the issue was not triggered, for example, by the query *Note `SELECT * FROM t WHERE b <= 8 OR b > 8': select. (Bug #57396) * A GCP stop is detected using 2 parameters which determine the maximum time that a global checkpoint or epoch can go unchanged; one of these controls this timeout for GCPs and one controls the timeout for epochs. Suppose the cluster is configured such that `TimeBetweenEpochsTimeout' is 100 ms but `HeartbeatIntervalDbDb' is 1500 ms. A node failure can be signalled after 4 missed heartbeats--in this case, 6000 ms. However, this would exceed `TimeBetweenEpochsTimeout', causing false detection of a GCP. To prevent this from happening, the configured value for `TimeBetweenEpochsTimeout' is automatically adjusted, based on the values of `HeartbeatIntervalDbDb' and `ArbitrationTimeout'. The current issue arose when the automatic adjustment routine did not correctly take into consideration the fact that, during cascading node-failures, several intervals of length `4 * (HeartbeatIntervalDBDB + ArbitrationTimeout)' may elapse before all node failures have internally been resolved. This could cause false GCP detection in the event of a cascading node failure. (Bug #57322) * Queries using `WHERE VARCHAR_PK_COLUMN LIKE 'PATTERN%'' or `WHERE VARCHAR_PK_COLUMN LIKE 'PATTERN_'' against an *Note `NDB': mysql-cluster. table having a *Note `VARCHAR': char. column as its primary key failed to return all matching rows. (Bug #56853) * When a data node angel process failed to fork off a new worker process (to replace one that had failed), the failure was not handled. This meant that the angel process either transformed itself into a worker process, or itself failed. In the first case, the data node continued to run, but there was no longer any angel to restart it in the event of failure, even with `StopOnError' set to 0. (Bug #53456) * *Disk Data*: Adding unique indexes to *Note `NDB': mysql-cluster. Disk Data tables could take an extremely long time. This was particularly noticeable when using *Note `ndb_restore `--rebuild-indexes'': mysql-cluster-programs-ndb-restore. (Bug #57827) * *Cluster Replication*: The `OPTION_ALLOW_BATCHING' bitmask had the same value as `OPTION_PROFILING'. This caused conflicts between using `--slave-allow-batching' and profiling. (Bug #57603) * *Cluster Replication*: Replication of *Note `SET': set. and *Note `ENUM': enum. columns represented using more than 1 byte (that is, *Note `SET': set. columns with more than 8 members and *Note `ENUM': enum. columns with more than 256 constants) between platforms using different endianness failed when using the row-based format. This was because columns of these types are represented internally using integers, but the internal functions used by MySQL to handle them treated them as strings. (Bug #52131) See also Bug #53528. * *Cluster API*: An application dropping a table at the same time that another application tried to set up a replication event on the same table could lead to a crash of the data node. The same issue could sometimes cause `NdbEventOperation::execute()' to hang. (Bug #57886) * *Cluster API*: An NDB API client program under load could abort with an assertion error in `TransporterFacade::remove_from_cond_wait_queue'. (Bug #51775) See also Bug #32708.  File: manual.info, Node: mysql-cluster-news-5-1-47-ndb-6-3-38, Next: mysql-cluster-news-5-1-47-ndb-6-3-37, Prev: mysql-cluster-news-5-1-51-ndb-6-3-39, Up: mysql-cluster-news-6-3 17.7.4.8 Changes in MySQL Cluster NDB 6.3.38 (5.1.47-ndb-6.3.38) (08 October 2010) .................................................................................. This is a bugfix release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.3 release. Obtaining MySQL Cluster NDB 6.3 The latest MySQL Cluster NDB 6.3 binaries for supported platforms can be obtained from `http://dev.mysql.com/downloads/cluster/'. Source code for the latest MySQL Cluster NDB 6.3 release can be obtained from the same location. You can also access the MySQL Cluster NDB 6.3 development source tree at `https://code.launchpad.net/~mysql/mysql-server/mysql-5.1-telco-6.3'. This release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.3 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.47 (see *Note news-5-1-47::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * *Note `mysqldump': mysqldump. as supplied with MySQL Cluster now has an `--add-drop-trigger' option which adds a *Note `DROP TRIGGER IF EXISTS': drop-trigger. statement before each dumped trigger definition. (Bug #55691) See also Bug #34325, Bug #11747863. * *Cluster API*: The MGM API function `ndb_mgm_get_version()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-get-version.html), which was previously internal, has now been moved to the public API. This function can be used to get `NDB' storage engine and other version information from the management server. (Bug #51310) See also Bug #51273. *Bugs fixed:* * A data node can be shut down having completed and synchronized a given GCI X, while having written a great many log records belonging to the next GCI X + 1, as part of normal operations. However, when starting, completing, and synchronizing GCI X + 1, then the log records from original start must not be read. To make sure that this does not happen, the REDO log reader finds the last GCI to restore, scans forward from that point, and erases any log records that were not (and should never be) used. The current issue occurred because this scan stopped immediately as soon as it encountered an empty page. This was problematic because the REDO log is divided into several files; thus, it could be that there were log records in the beginning of the next file, even if the end of the previous file was empty. These log records were never invalidated; following a start or restart, they could be reused, leading to a corrupt REDO log. (Bug #56961) * An error in program flow in `ndbd.cpp' could result in data node shutdown routines being called multiple times. (Bug #56890) * When distributing *Note `CREATE TABLE': create-table. and *Note `DROP TABLE': drop-table. operations among several SQL nodes attached to a MySQL Cluster. the `LOCK_OPEN' lock normally protecting *Note `mysqld': mysqld.'s internal table list is released so that other queries or DML statements are not blocked. However, to make sure that other DDL is not executed simultaneously, a global schema lock (implemented as a row-level lock by `NDB') is used, such that all operations that can modify the state of the *Note `mysqld': mysqld. internal table list also need to acquire this global schema lock. The *Note `SHOW TABLE STATUS': show-table-status. statement did not acquire this lock. (Bug #56841) * In certain cases, *Note `DROP DATABASE': drop-database. could sometimes leave behind a cached table object, which caused problems with subsequent DDL operations. (Bug #56840) * Memory pages used for `DataMemory', once assigned to ordered indexes, were not ever freed, even after any rows that belonged to the corresponding indexes had been deleted. (Bug #56829) * MySQL Cluster stores, for each row in each `NDB' table, a Global Checkpoint Index (GCI) which identifies the last committed transaction that modified the row. As such, a GCI can be thought of as a coarse-grained row version. Due to changes in the format used by `NDB' to store local checkpoints (LCPs) in MySQL Cluster NDB 6.3.11, it could happen that, following cluster shutdown and subsequent recovery, the GCI values for some rows could be changed unnecessarily; this could possibly, over the course of many node or system restarts (or both), lead to an inconsistent database. (Bug #56770) * When multiple SQL nodes were connected to the cluster and one of them stopped in the middle of a DDL operation, the *Note `mysqld': mysqld. process issuing the DDL timed out with the error `distributing TBL_NAME timed out. Ignoring'. (Bug #56763) * An online *Note `ALTER TABLE ... ADD COLUMN': alter-table. operation that changed the table schema such that the number of 32-bit words used for the bitmask allocated to each DML operation increased during a transaction in DML which was performed prior to DDL which was followed by either another DML operation or--if using replication--a commit, led to data node failure. This was because the data node did not take into account that the bitmask for the before-image was smaller than the current bitmask, which caused the node to crash. (Bug #56524) * The text file `cluster_change_hist.txt' containing old MySQL Cluster changelog information was no longer being maintained, and so has been removed from the tree. (Bug #56116) * The failure of a data node during some scans could cause other data nodes to fail. (Bug #54945) * Exhausting the number of available commit-ack markers (controlled by the `MaxNoOfConcurrentTransactions' parameter) led to a data node crash. (Bug #54944) * When running a *Note `SELECT': select. on an *Note `NDB': mysql-cluster. table with *Note `BLOB': blob. or *Note `TEXT': blob. columns, memory was allocated for the columns but was not freed until the end of the *Note `SELECT': select. This could cause problems with excessive memory usage when dumping (using for example *Note `mysqldump': mysqldump.) tables with such columns and having many rows, large column values, or both. (Bug #52313) See also Bug #56488, Bug #50310. * *Cluster Replication*: When an SQL node starts, as part of setting up replication, it subscribes to data events from all data nodes using a `SUB_START_REQ' (subscription start request) signal. Atomicity of `SUB_START_REQ' is implemented such that, if any of the nodes returns an error, a `SUB_STOP_REQ' (subscription stop request) is sent to any nodes that replied with a `SUB_START_CONF' (subscription start confirmation). However, if all data nodes returned an error, `SUB_STOP_REQ' was not sent to any of them. This caused mysqld to hang when restarting (while waiting for a response), and subsequent data node restarts to hang as well. (Bug #56579) * *Cluster Replication*: When a *Note `mysqld': mysqld. process was shut down while it was still performing updates, it was possible for the entry containing binary log information for the final epoch preceding shutdown to be omitted from the `mysql.ndb_binlog_index' table. This could somtimes occur even during a normal shutdown of *Note `mysqld': mysqld. (Bug #55909) * *Cluster Replication*: The graceful shutdown of a data node in the master cluster could sometimes cause rows to be skipped when writing transactions to the binary log. Testing following an initial fix for this issue revealed an additional case where the graceful shutdown of a data node was not handled properly. The current fix addresses this case. (Bug #55641) See also Bug #18538.  File: manual.info, Node: mysql-cluster-news-5-1-47-ndb-6-3-37, Next: mysql-cluster-news-5-1-47-ndb-6-3-36, Prev: mysql-cluster-news-5-1-47-ndb-6-3-38, Up: mysql-cluster-news-6-3 17.7.4.9 Changes in MySQL Cluster NDB 6.3.37 (5.1.47-ndb-6.3.37) (03 September 2010) .................................................................................... This is a bugfix release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.3 release. Obtaining MySQL Cluster NDB 6.3 The latest MySQL Cluster NDB 6.3 binaries for supported platforms can be obtained from `http://dev.mysql.com/downloads/cluster/'. Source code for the latest MySQL Cluster NDB 6.3 release can be obtained from the same location. You can also access the MySQL Cluster NDB 6.3 development source tree at `https://code.launchpad.net/~mysql/mysql-server/mysql-5.1-telco-6.3'. This release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.3 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.47 (see *Note news-5-1-47::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * *Important Change*: More finely-grained control over restart-on-failure behavior is provided with two new data node configuration parameters `MaxStartFailRetries' and `StartFailRetryDelay'. `MaxStartFailRetries' limits the total number of retries made before giving up on starting the data node; `StartFailRetryDelay' sets the number of seconds between retry attempts. These parameters are used only if `StopOnError' is set to 0. For more information, see *Note mysql-cluster-ndbd-definition::. (Bug #54341) *Bugs fixed:* * Following a failure of the master data node, the new master sometimes experienced a race condition which caused the node to terminate with a GcpStop error. (Bug #56044) * The warning `MaxNoOfExecutionThreads (#) > LockExecuteThreadToCPU count (#), this could cause contention' could be logged when running *Note `ndbd': mysql-cluster-programs-ndbd, even though the condition described can occur only when using *Note `ndbmtd': mysql-cluster-programs-ndbmtd. (Bug #54342) * The graceful shutdown of a data node could sometimes cause transactions to be aborted unnecessarily. (Bug #18538) See also Bug #55641. * *Cluster Replication*: The graceful shutdown of a data node in the master cluster could sometimes cause rows to be skipped when writing transactions to the binary log, leading to an inconsistent slave cluster. (Bug #55641) See also Bug #18538. * *Cluster Replication*: Specifying the `--expire_logs_days' option when there were old binary logs to delete caused SQL nodes to crash on startup. (Bug #41751)  File: manual.info, Node: mysql-cluster-news-5-1-47-ndb-6-3-36, Next: mysql-cluster-news-5-1-47-ndb-6-3-35, Prev: mysql-cluster-news-5-1-47-ndb-6-3-37, Up: mysql-cluster-news-6-3 17.7.4.10 Changes in MySQL Cluster NDB 6.3.36 (5.1.47-ndb-6.3.36) (16 August 2010) .................................................................................. This is a bugfix release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.3 release. Obtaining MySQL Cluster NDB 6.3 The latest MySQL Cluster NDB 6.3 binaries for supported platforms can be obtained from `http://dev.mysql.com/downloads/cluster/'. Source code for the latest MySQL Cluster NDB 6.3 release can be obtained from the same location. You can also access the MySQL Cluster NDB 6.3 development source tree at `https://code.launchpad.net/~mysql/mysql-server/mysql-5.1-telco-6.3'. This release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.3 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.47 (see *Note news-5-1-47::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * Added the `DictTrace' data node configuration parameter, for use in debugging *Note `NDB': mysql-cluster. code. For more information, see *Note mysql-cluster-ndbd-definition::. (Bug #55963) *Bugs fixed:* * *Cluster API*: *Important Change*: The poll and select calls made by the MGM API were not interrupt-safe; that is, a signal caught by the process while waiting for an event on one or more sockets returned error -1 with `errno' set to EINTR. This caused problems with MGM API functions such as `ndb_logevent_get_next()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-logevent-get-next.html) and `ndb_mgm_get_status2()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-get-status2.html). To fix this problem, the internal `ndb_socket_poller::poll()' function has been made EINTR-safe. The old version of this function has been retained as `poll_unsafe()', for use by those parts of NDB that do not need the EINTR-safe version of the function. (Bug #55906) * When another data node failed, a given data node `DBTC' kernel block could time out while waiting for `DBDIH' to signal commits of pending transactions, leading to a crash. Now in such cases the timeout generates a prinout, and the data node continues to operate. (Bug #55715) * The `configure.js' option `WITHOUT_DYNAMIC_PLUGINS=TRUE' was ignored when building MySQL Cluster for Windows using `CMake'. Among the effects of this issue was that `CMake' attempted to build the `InnoDB' storage engine as a plugin (`.DLL' file) even though the `InnoDB Plugin' is not currently supported by MySQL Cluster. (Bug #54913) * It was possible for a *Note `DROP DATABASE': drop-database. statement to remove *Note `NDB': mysql-cluster. hidden blob tables without removing the parent tables, with the result that the tables, although hidden to MySQL clients, were still visible in the output of *Note `ndb_show_tables': mysql-cluster-programs-ndb-show-tables. but could not be dropped using *Note `ndb_drop_table': mysql-cluster-programs-ndb-drop-table. (Bug #54788) * An excessive number of timeout warnings (normally used only for debugging) were written to the data node logs. (Bug #53987) * *Disk Data*: As an optimization when inserting a row to an empty page, the page is not read, but rather simply initialized. However, this optimzation was performed in all cases when an empty row was inserted, even though it should have been done only if it was the first time that the page had been used by a table or fragment. This is because, if the page had been in use, and then all records had been released from it, the page still needed to be read to learn its log sequence number (LSN). This caused problems only if the page had been flushed using an incorrect LSN and the data node failed before any local checkpoint was completed--which would removed any need to apply the undo log, hence the incorrect LSN was ignored. The user-visible result of the incorrect LSN was that it caused the data node to fail during a restart. It was perhaps also possible (although not conclusively proven) that this issue could lead to incorrect data. (Bug #54986) * *Cluster Replication*: When inserting rows into the `mysql.ndb_binlog_index' table, duplicate key errors occurred when the size of the epoch number (a 64-bit integer) exceeded 2^53. This happened because the `NDB' storage engine handler called the wrong overloaded variant of a MySQL Server internal API (the `Field::store()' method), which resulted in the epoch being mapped to a 64-bit double precision floating point number and a corresponding loss of accuracy for numbers greater than 2^53. (Bug #35217) * *Cluster API*: Calling `NdbTransaction::refresh()' did not update the timer for `TransactionInactiveTimeout'. (Bug #54724)  File: manual.info, Node: mysql-cluster-news-5-1-47-ndb-6-3-35, Next: mysql-cluster-news-5-1-44-ndb-6-3-34, Prev: mysql-cluster-news-5-1-47-ndb-6-3-36, Up: mysql-cluster-news-6-3 17.7.4.11 Changes in MySQL Cluster NDB 6.3.35 (5.1.47-ndb-6.3.35) (25 June 2010) ................................................................................ This is a bugfix release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.3 release. This release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.3 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.47 (see *Note news-5-1-47::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * Restrictions on some types of mismatches in column definitions when restoring data using *Note `ndb_restore': mysql-cluster-programs-ndb-restore. have been relaxed. These include the following types of mismatches: * Different `COLUMN_FORMAT' settings (`FIXED', `DYNAMIC', `DEFAULT') * Different `STORAGE' settings (`MEMORY', `DISK') * Different default values * Different distribution key settings Now, when one of these types of mismatches in column definitions is encountered, *Note `ndb_restore': mysql-cluster-programs-ndb-restore. no longer stops with an error; instead, it accepts the data and inserts it into the target table, while issuing a warning to the user. For more information, see *Note mysql-cluster-programs-ndb-restore::. (Bug #54423) See also Bug #53810, Bug #54178, Bug #54242, Bug #54279. * Introduced the `HeartbeatOrder' data node configuration parameter, which can be used to set the order in which heartbeats are transmitted between data nodes. This parameter can be useful in situations where multiple data nodes are running on the same host and a temporary disruption in connectivity between hosts would otherwise cause the loss of a node group, leading to failure of the cluster. (Bug #52182) *Bugs fixed:* * The disconnection of all API nodes (including SQL nodes) during an *Note `ALTER TABLE': alter-table. caused a memory leak. (Bug #54685) * If a node shutdown (either in isolation or as part of a system shutdown) occurred directly following a local checkpoint, it was possible that this local checkpoint would not be used when restoring the cluster. (Bug #54611) * When performing an online alter table where 2 or more SQL nodes connected to the cluster were generating binary logs, an incorrect message could be sent from the data nodes, causing *Note `mysqld': mysqld. processes to crash. This problem was often difficult to detect, because restarting SQL node or data node processes could clear the error, and because the crash in *Note `mysqld': mysqld. did not occur until several minutes after the erroneous message was sent and received. (Bug #54168) * A table having the maximum number of attributes permitted could not be backed up using the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client. *Note*: The maximum number of attributes supported per table is not the same for all MySQL Cluster releases. See *Note mysql-cluster-limitations-database-objects::, to determine the maximum that applies in the release which you are using. (Bug #54155) * During initial node restarts, initialization of the REDO log was always performed 1 node at a time, during start phase 4. Now this is done during start phase 2, so that the initialization can be performed in parallel, thus decreasing the time required for initial restarts involving multiple nodes. (Bug #50062) * *Cluster Replication*: An error in an `NDB' internal byte mask value could lead to corruption of replicated *Note `BIT': numeric-types. column values. (Bug #54005) See also Bug #53622. * *Cluster API*: When using the NDB API, it was possible to rename a table with the same name as that of an existing table. *Note*: This issue did not affect table renames executed using SQL on MySQL servers acting as MySQL Cluster API nodes. (Bug #54651) * *Cluster API*: An excessive number of client connections, such that more than 1024 file descriptors, sockets, or both were open, caused NDB API applications to crash. (Bug #34303)  File: manual.info, Node: mysql-cluster-news-5-1-44-ndb-6-3-34, Next: mysql-cluster-news-5-1-44-ndb-6-3-33, Prev: mysql-cluster-news-5-1-47-ndb-6-3-35, Up: mysql-cluster-news-6-3 17.7.4.12 Changes in MySQL Cluster NDB 6.3.34 (5.1.44-ndb-6.3.34) (31 May 2010) ............................................................................... This is a bugfix release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.3 release. This is a source-only release. You can obtain the GPL source code for MySQL Cluster NDB 6.3.34 from `ftp://ftp.mysql.com/pub/mysql/download/cluster_telco/mysql-5.1.44-ndb-6.3.34/'. This release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.3 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.44 (see *Note news-5-1-44::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * A `--wait-nodes' option has been added for *Note `ndb_waiter': mysql-cluster-programs-ndb-waiter. When this option is used, the program waits only for the nodes having the listed IDs to reach the desired state. For more information, see *Note mysql-cluster-programs-ndb-waiter::. (Bug #52323) * Added the `--skip-unknown-objects' option for *Note `ndb_restore': mysql-cluster-programs-ndb-restore. This option causes *Note `ndb_restore': mysql-cluster-programs-ndb-restore. to ignore any schema objects which it does not recognize. Currently, this is useful chiefly for restoring native backups made from a cluster running MySQL Cluster NDB 7.0 to a cluster running MySQL Cluster NDB 6.3. *Bugs fixed:* * *Cluster API*: *Incompatible Change*: The default behavior of the NDB API Event API has changed as follows: Previously, when creating an `Event', DDL operations (alter and drop operations on tables) were automatically reported on any event operation that used this event, but as a result of this change, this is no longer the case. Instead, you must now invoke the event's `setReport()' method, with the new `EventReport' value `ER_DDL', to get this behavior. For existing NDB API applications where you wish to retain the old behavior, you must update the code as indicated previously, then recompile, following an upgrade. Otherwise, DDL operations are no longer reported after upgrading `libndbnclient'. For more information, see The `Event::EventReport' Type (http://dev.mysql.com/doc/ndbapi/en/ndb-event-types.html#ndb-event-eventreport), and `Event::setReport()' (http://dev.mysql.com/doc/ndbapi/en/ndb-event-methods.html#ndb-event-setreport). (Bug #53308) * Creating a Disk Data table, dropping it, then creating an in-memory table and performing a restart, could cause data node processes to fail with errors in the `DBTUP' kernel block if the new table's internal ID was the same as that of the old Disk Data table. This could occur because undo log handling during the restart did not check that the table having this ID was now in-memory only. (Bug #53935) * A table created while `ndb_table_no_logging' was enabled was not always stored to disk, which could lead to a data node crash with `Error opening DIH schema files for table'. (Bug #53934) * An internal buffer allocator used by *Note `NDB': mysql-cluster. has the form `alloc(WANTED, MINIMUM)' and attempts to allocate WANTED pages, but is permitted to allocate a smaller number of pages, between WANTED and MINIMUM. However, this allocator could sometimes allocate fewer than MINIMUM pages, causing problems with multi-threaded building of ordered indexes. (Bug #53580) * When compiled with support for `epoll' but this functionality is not available at runtime, MySQL Cluster tries to fall back to use the `select()' function in its place. However, an extra `ndbout_c()' call in the transporter registry code caused *Note `ndbd': mysql-cluster-programs-ndbd. to fail instead. (Bug #53482) * `NDB' truncated a column declared as *Note `DECIMAL(65,0)': numeric-types. to a length of 64. Now such a column is accepted and handled correctly. In cases where the maximum length (65) is exceeded, `NDB' now raises an error instead of truncating. (Bug #53352) * When a watchdog shutdown occurred due to an error, the process was not terminated quickly enough, sometimes resulting in a hang. (To correct this, the internal `_exit()' function is now called in such situations, rather than `exit()'.) (Bug #53246) * Setting `DataMemory' higher than 4G on 32-bit platforms caused *Note `ndbd': mysql-cluster-programs-ndbd. to crash, instead of failing gracefully with an error. (Bug #52536, Bug #50928) * NDB did not distinguish correctly between table names differing only by lettercase when `lower_case_table_names' was set to 0. (Bug #33158) * `ndb_mgm -e "ALL STATUS"' erroneously reported that data nodes remained in start phase 0 until they had actually started. * *Replication*: A buffer overrun in the handling of *Note `DATE': datetime. column values could cause mysqlbinlog to fail when reading back logs containing certain combinations of DML on a table having a *Note `DATE': datetime. column followed by dropping the table. (Bug #52202) * *Cluster Replication*: Replication failed after a restart of the slave SQL node, due to an error in writing the `master.info' file. (Bug #52859) * *Note `ALTER TABLE': alter-table. did not work correctly where the name of the table, the database, or both contained special characters, causing the MySQL server to crash. (Bug #52225) See also Bug #53409, Bug #14959.  File: manual.info, Node: mysql-cluster-news-5-1-44-ndb-6-3-33, Next: mysql-cluster-news-5-1-41-ndb-6-3-32, Prev: mysql-cluster-news-5-1-44-ndb-6-3-34, Up: mysql-cluster-news-6-3 17.7.4.13 Changes in MySQL Cluster NDB 6.3.33 (5.1.44-ndb-6.3.33) (31 March 2010) ................................................................................. This is a bugfix release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.3 release. You can obtain the GPL source code and GPL binaries for supported platforms for MySQL Cluster NDB 6.3.33 from `http://dev.mysql.com/downloads/cluster/'. This release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.3 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.44 (see *Note news-5-1-44::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * *Cluster API*: It is now possible to determine, using the *Note `ndb_desc': mysql-cluster-programs-ndb-desc. utility or the NDB API, which data nodes contain replicas of which partitions. For *Note `ndb_desc': mysql-cluster-programs-ndb-desc, a new `--extra-node-info' option is added to cause this information to be included in its output. A new method `Table::getFragmentNodes()' is added to the NDB API for obtaining this information programmatically. (Bug #51184) * Formerly, the `REPORT' and `DUMP' commands returned output to all *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. clients connected to the same MySQL Cluster. Now, these commands return their output only to the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client that actually issued the command. (Bug #40865) * *Cluster Replication*: *Replication*: MySQL Cluster Replication now supports attribute promotion and demotion for row-based replication between columns of different but similar types on the master and the slave. For example, it is possible to promote an *Note `INT': numeric-types. column on the master to a *Note `BIGINT': numeric-types. column on the slave, and to demote a *Note `TEXT': blob. column to a *Note `VARCHAR': char. column. The implementation of type demotion distinguishes between lossy and non-lossy type conversions, and their use on the slave can be controlled by setting the `slave_type_conversions' global server system variable. For more information about attribute promotion and demotion for row-based replication in MySQL Cluster, see *Note replication-features-attribute-promotion::. (Bug #47163, Bug #46584) *Bugs fixed:* * If a node or cluster failure occurred while *Note `mysqld': mysqld. was scanning the `ndb.ndb_schema' table (which it does when attempting to connect to the cluster), insufficient error handling could lead to a crash by *Note `mysqld': mysqld. in certain cases. This could happen in a MySQL Cluster with a great many tables, when trying to restart data nodes while one or more *Note `mysqld': mysqld. processes were restarting. (Bug #52325) * After running a mixed series of node and system restarts, a system restart could hang or fail altogether. This was caused by setting the value of the newest completed global checkpoint too low for a data node performing a node restart, which led to the node reporting incorrect GCI intervals for its first local checkpoint. (Bug #52217) * When performing a complex mix of node restarts and system restarts, the node that was elected as master sometimes required optimized node recovery due to missing `REDO' information. When this happened, the node crashed with `Failure to recreate object ... during restart, error 721' (because the `DBDICT' restart code was run twice). Now when this occurs, node takeover is executed immediately, rather than being made to wait until the remaining data nodes have started. (Bug #52135) See also Bug #48436. * The redo log protects itself from being filled up by periodically checking how much space remains free. If insufficient redo log space is available, it sets the state `TAIL_PROBLEM' which results in transactions being aborted with error code 410 (`out of redo log'). However, this state was not set following a node restart, which meant that if a data node had insufficient redo log space following a node restart, it could crash a short time later with `Fatal error due to end of REDO log'. Now, this space is checked during node restarts. (Bug #51723) * The output of the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client `REPORT BACKUPSTATUS' command could sometimes contain errors due to uninitialized data. (Bug #51316) * A `GROUP BY' query against *Note `NDB': mysql-cluster. tables sometimes did not use any indexes unless the query included a `FORCE INDEX' option. With this fix, indexes are used by such queries (where otherwise possible) even when `FORCE INDEX' is not specified. (Bug #50736) * The *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client sometimes inserted extra prompts within the output of the `REPORT MEMORYUSAGE' command. (Bug #50196) * Issuing a command in the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client after it had lost its connection to the management server could cause the client to crash. (Bug #49219) * The *Note `ndb_print_backup_file': mysql-cluster-programs-ndb-print-backup-file. utility failed to function, due to a previous internal change in the NDB code. (Bug #41512, Bug #48673) * When the `MemReportFrequency' configuration parameter was set in `config.ini', the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client `REPORT MEMORYUSAGE' command printed its output multiple times. (Bug #37632) * *Note `ndb_mgm -e "... REPORT ..."': mysql-cluster-programs-ndb-mgm. did not write any output to `stdout'. The fix for this issue also prevents the cluster log from being flooded with `INFO' messages when `DataMemory' usage reaches 100%, and insures that when the usage is decreased, an appropriate message is written to the cluster log. (Bug #31542, Bug #44183, Bug #49782) * *InnoDB Storage Engine*: *Replication*: Column length information generated by *Note `InnoDB': innodb-storage-engine. did not match that generated by *Note `MyISAM': myisam-storage-engine, which caused invalid metadata to be written to the binary log when trying to replicate *Note `BIT': numeric-types. columns. (Bug #49618) * *Replication*: Metadata for `GEOMETRY' fields was not properly stored by the slave in its definitions of tables. (Bug #49836) See also Bug #48776. * *Disk Data*: Inserts of blob column values into a MySQL Cluster Disk Data table that exhausted the tablespace resulted in misleading `no such tuple' error messages rather than the expected error `tablespace full'. This issue appeared similar to Bug#48113, but had a different underlying cause. (Bug #52201) * *Disk Data*: The error message returned after atttempting to execute *Note `ALTER LOGFILE GROUP': alter-logfile-group. on an nonexistent logfile group did not indicate the reason for the failure. (Bug #51111) * *Cluster Replication*: The `--ndb-log-empty-epochs' option did not work correctly. (Bug #49559) * *Cluster Replication*: When *Note `mysqld': mysqld. was started with `--binlog-do-db' or `--binlog-ignore-db', no `LOST_EVENTS' incident was written to the binary log. (Bug #47096) * *Cluster API*: When reading blob data with lock mode `LM_SimpleRead', the lock was not upgraded as expected. (Bug #51034) * *Cluster API*: A number of issues were corrected in the NDB API coding examples found in the `storage/ndb/ndbapi-examples' directory in the MySQL Cluster source tree. These included possible endless recursion in `ndbapi_scan.cpp' as well as problems running some of the examples on systems using Windows or Mac OS X due to the lettercase used for some table names. (Bug #30552, Bug #30737) * 1) In rare cases, if a thread was interrupted during a *Note `FLUSH PRIVILEGES': flush. operation, a debug assertion occurred later due to improper diagnostics area setup. 2) A *Note `KILL': kill. operation could cause a console error message referring to a diagnostic area state without first ensuring that the state existed. (Bug #33982)  File: manual.info, Node: mysql-cluster-news-5-1-41-ndb-6-3-32, Next: mysql-cluster-news-5-1-41-ndb-6-3-31b, Prev: mysql-cluster-news-5-1-44-ndb-6-3-33, Up: mysql-cluster-news-6-3 17.7.4.14 Changes in MySQL Cluster NDB 6.3.32 (5.1.41-ndb-6.3.32) (04 March 2010) ................................................................................. This is a bugfix release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.3 release. This release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.3 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.41 (see *Note news-5-1-41::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * A new configuration parameter `HeartbeatThreadPriority' makes it possible to select between a first-in, first-out or round-round scheduling policy for management node and API node heartbeat threads, as well as to set the priority of these threads. See *Note mysql-cluster-mgm-definition::, or *Note mysql-cluster-api-definition::, for more information. (Bug #49617) * *Disk Data*: The *Note `ndb_desc': mysql-cluster-programs-ndb-desc. utility can now show the extent space and free extent space for subordinate *Note `BLOB': blob. and *Note `TEXT': blob. columns (stored in hidden `BLOB' tables by NDB). A `--blob-info' option has been added for this program that causes *Note `ndb_desc': mysql-cluster-programs-ndb-desc. to generate a report for each subordinate `BLOB' table. For more information, see *Note mysql-cluster-programs-ndb-desc::. (Bug #50599) *Bugs fixed:* * When one or more data nodes read their LCPs and applied undo logs significantly faster than others, this could lead to a race condition causing system restarts of data nodes to hang. This could most often occur when using both *Note `ndbd': mysql-cluster-programs-ndbd. and *Note `ndbmtd': mysql-cluster-programs-ndbmtd. processes for the data nodes. (Bug #51644) * When deciding how to divide the REDO log, the `DBDIH' kernel block saved more than was needed to restore the previous local checkpoint, which could cause REDO log space to be exhausted prematurely (`NDB' error 410). (Bug #51547) * DML operations can fail with `NDB' error 1220 (`REDO log files overloaded...') if the opening and closing of REDO log files takes too much time. If this occurred as a GCI marker was being written in the REDO log while REDO log file 0 was being opened or closed, the error could persist until a GCP stop was encountered. This issue could be triggered when there was insufficient REDO log space (for example, with configuration parameter settings `NoOfFragmentLogFiles = 6' and `FragmentLogFileSize = 6M') with a load including a very high number of updates. (Bug #51512) See also Bug #20904. * During an online upgrade from MySQL Cluster NDB 6.2 to MySQL Cluster NDB 6.3, a sufficiently large amount of traffic with more than 1 DML operation per transaction could lead.an NDB 6.3 data node to crash an NDB 6.2 data node with an internal error in the `DBLOQH' kernel block. (Bug #51389) * A side effect of the *Note `ndb_restore': mysql-cluster-programs-ndb-restore. `--disable-indexes' and `--rebuild-indexes' options is to change the schema versions of indexes. When a *Note `mysqld': mysqld. later tried to drop a table that had been restored from backup using one or both of these options, the server failed to detect these changed indexes. This caused the table to be dropped, but the indexes to be left behind, leading to problems with subsequent backup and restore operations. (Bug #51374) * *Note `ndb_restore': mysql-cluster-programs-ndb-restore. crashed while trying to restore a corrupted backup, due to missing error handling. (Bug #51223) * The *Note `ndb_restore': mysql-cluster-programs-ndb-restore. message `Successfully created index `PRIMARY`...' was directed to `stderr' instead of `stdout'. (Bug #51037) * When using `NoOfReplicas' equal to 1 or 2, if data nodes from one node group were restarted 256 times and applications were running traffic such that it would encounter *Note `NDB': mysql-cluster. error 1204 (`Temporary failure, distribution changed'), the live node in the node group would crash, causing the cluster to crash as well. The crash occurred only when the error was encountered on the 256th restart; having the error on any previous or subsequent restart did not cause any problems. (Bug #50930) * A *Note `SELECT': select. requiring a sort could fail with the error `Can't find record in 'TABLE'' when run concurrently with a *Note `DELETE': delete. from the same table. (Bug #45687) * *Cluster API*: An issue internal to *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. could cause problems when trying to start a large number of data nodes at the same time. (Bug #51273) See also Bug #51310.  File: manual.info, Node: mysql-cluster-news-5-1-41-ndb-6-3-31b, Next: mysql-cluster-news-5-1-41-ndb-6-3-31a, Prev: mysql-cluster-news-5-1-41-ndb-6-3-32, Up: mysql-cluster-news-6-3 17.7.4.15 Changes in MySQL Cluster NDB 6.3.31b (5.1.41-ndb-6.3.31b) (18 February 2010) ...................................................................................... This is a replacement release for MySQL Cluster NDB 6.3.31a, fixing a critical issue in that version that was discovered shortly after its release (Bug#51256). MySQL Cluster NDB 6.3.31b is identical in all other respects to MySQL Cluster NDB 6.3.31a. Users of MySQL Cluster NDB 6.3.31 or MySQL Cluster NDB 6.3.31a should upgrade to the 6.3.31b release as soon as possible. Users of previous MySQL Cluster NDB 6.3 releases should bypass the 6.3.31 and 6.3.31a releases, and upgrade to 6.3.31b instead. Obtaining MySQL Cluster NDB 6.3.31b This is a source-only release. You can obtain the GPL source code for MySQL Cluster NDB 6.3.31b from `ftp://ftp.mysql.com/pub/mysql/download/cluster_telco/mysql-5.1.41-ndb-6.3.31b/'. You can also access the MySQL Cluster NDB 6.3 development source tree at `https://code.launchpad.net/~mysql/mysql-server/mysql-5.1-telco-6.3'. This release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.3 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.41 (see *Note news-5-1-41::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Bugs fixed:* * Setting `IndexMemory' greater than 2GB could cause data nodes to crash while starting. (Bug #51256)  File: manual.info, Node: mysql-cluster-news-5-1-41-ndb-6-3-31a, Next: mysql-cluster-news-5-1-41-ndb-6-3-31, Prev: mysql-cluster-news-5-1-41-ndb-6-3-31b, Up: mysql-cluster-news-6-3 17.7.4.16 Changes in MySQL Cluster NDB 6.3.31a (5.1.41-ndb-6.3.31a) (15 February 2010) ...................................................................................... *Note*: MySQL Cluster NDB 6.3.31a was withdrawn shortly after release, due to Bug#51256. Users should upgrade to MySQL Cluster NDB 6.3.31b, which fixes this issue. This is a replacement release for MySQL Cluster NDB 6.3.31, fixing a critical issue in that version that was discovered shortly after its release (Bug#51027). MySQL Cluster NDB 6.3.31a is identical in all other respects to MySQL Cluster NDB 6.3.31. Users of MySQL Cluster NDB 6.3.31 should upgrade to the 6.3.31a release as soon as possible. Users of previous MySQL Cluster NDB 6.3 releases should bypass the 6.3.31 release and upgrade to 6.3.31a instead. Obtaining MySQL Cluster NDB 6.3.31a This is a source-only release. You can obtain the GPL source code for MySQL Cluster NDB 6.3.31a from `ftp://ftp.mysql.com/pub/mysql/download/cluster_telco/mysql-5.1.41-ndb-6.3.31a/'. You can also access the MySQL Cluster NDB 6.3 development source tree at `https://code.launchpad.net/~mysql/mysql-server/mysql-5.1-telco-6.3'. This release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.3 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.41 (see *Note news-5-1-41::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Bugs fixed:* * An initial restart of a data node configured with a large amount of memory could fail with a `Pointer too large' error. (Bug #51027) This regression was introduced by Bug #47818.  File: manual.info, Node: mysql-cluster-news-5-1-41-ndb-6-3-31, Next: mysql-cluster-news-5-1-39-ndb-6-3-30, Prev: mysql-cluster-news-5-1-41-ndb-6-3-31a, Up: mysql-cluster-news-6-3 17.7.4.17 Changes in MySQL Cluster NDB 6.3.31 (5.1.41-ndb-6.3.31) (02 February 2010) .................................................................................... *Note*: MySQL Cluster NDB 6.3.31 was withdrawn shortly after release, due to Bug#51027. Users should upgrade to MySQL Cluster NDB 6.3.31a, which fixes this issue. This is a bugfix release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.3 release. This release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.3 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.41 (see *Note news-5-1-41::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * *Important Change*: The maximum permitted value of the `ndb_autoincrement_prefetch_sz' system variable has been increased from 256 to 65536. (Bug #50621) * *Cluster Replication*: Due to the fact that no timestamp is available for delete operations, a delete using `NDB$MAX()' is actually processed as `NDB$OLD'. However, because this is not optimal for some use cases, `NDB$MAX_DELETE_WIN()' is added as a conflict resolution function; if the `timestamp' column value for a given row adding or updating an existing row coming from the master is higher than that on the slave, it is applied (as with `NDB$MAX()'); however, delete operations are treated as always having the higher value. See *Note mysql-cluster-replication-ndb-max-delete-win::, for more information. (Bug #50650) * *Cluster Replication*: In circular replication, it was sometimes possible for an event to propagate such that it would be reapplied on all servers. This could occur when the originating server was removed from the replication circle and so could no longer act as the terminator of its own events, as normally happens in circular replication. To prevent this from occurring, a new `IGNORE_SERVER_IDS' option is introduced for the `CHANGE MASTER TO' statement. This option takes a list of replication server IDs; events having a server ID which appears in this list are ignored and not applied. For more information, see *Note change-master-to::. In conjunction with the introduction of `IGNORE_SERVER_IDS', *Note `SHOW SLAVE STATUS': show-slave-status. has two new fields. `Replicate_Ignore_Server_Ids' displays information about ignored servers. `Master_Server_Id' displays the `server_id' value from the master. (Bug #47037) See also Bug #25998, Bug #27808. *Bugs fixed:* * Setting `BuildIndexThreads' greater than 1 with more than 31 ordered indexes caused node and system restarts to fail. (Bug #50266) * Dropping unique indexes in parallel while they were in use could cause node and cluster failures. (Bug #50118) * When setting the `LockPagesInMainMemory' configuration parameter failed, only the error `Failed to memlock pages...' was returned. Now in such cases the operating system's error code is also returned. (Bug #49724) * If a query on an *Note `NDB': mysql-cluster. table compared a constant string value to a column, and the length of the string was greater than that of the column, condition pushdown did not work correctly. (The string was truncated to fit the column length before being pushed down.) Now in such cases, the condition is no longer pushed down. (Bug #49459) * Performing intensive inserts and deletes in parallel with a high scan load could a data node crashes due to a failure in the `DBACC' kernel block. This was because checking for when to perform bucket splits or merges considered the first 4 scans only. (Bug #48700) * During Start Phases 1 and 2, the `STATUS' command sometimes (falsely) returned `Not Connected' for data nodes running *Note `ndbmtd': mysql-cluster-programs-ndbmtd. (Bug #47818) * When performing a *Note `DELETE': delete. that included a left join from an *Note `NDB': mysql-cluster. table, only the first matching row was deleted. (Bug #47054) * *Note `mysqld': mysqld. could sometimes crash during a commit while trying to handle NDB Error 4028 `Node failure caused abort of transaction'. (Bug #38577) * When setting `LockPagesInMainMemory', the stated memory was not allocated when the node was started, but rather only when the memory was used by the data node process for other reasons. (Bug #37430) * Trying to insert more rows than would fit into an `NDB' table caused data nodes to crash. Now in such situations, the insert fails gracefully with error 633 `Table fragment hash index has reached maximum possible size'. (Bug #34348) * *Disk Data*: When a crash occurs due to a problem in Disk Data code, the currently active page list is printed to `stdout' (that is, in one or more `ndb_NODEID_out.log' files). One of these lists could contain an endless loop; this caused a printout that was effectively never-ending. Now in such cases, a maximum of 512 entries is printed from each list. (Bug #42431) * On Mac OS X or Windows, sending a `SIGHUP' signal to the server or an asynchronous flush (triggered by `flush_time') caused the server to crash. (Bug #47525) * The *Note `ARCHIVE': archive-storage-engine. storage engine lost records during a bulk insert. (Bug #46961) * When using the *Note `ARCHIVE': archive-storage-engine. storage engine, `SHOW TABLE STATUS' displayed incorrect information for `Max_data_length', `Data_length' and `Avg_row_length'. (Bug #29203)  File: manual.info, Node: mysql-cluster-news-5-1-39-ndb-6-3-30, Next: mysql-cluster-news-5-1-39-ndb-6-3-29, Prev: mysql-cluster-news-5-1-41-ndb-6-3-31, Up: mysql-cluster-news-6-3 17.7.4.18 Changes in MySQL Cluster NDB 6.3.30 (5.1.39-ndb-6.3.30) (15 December 2009) .................................................................................... This special-purpose evaluation release incorporates all bugfixes and feature changes from previous MySQL Cluster NDB 6.3 releases plus one new feature for evaluation. Most users of MySQL Cluster NDB 6.3 do not require this release; instead, you should use MySQL Cluster NDB 6.3.29 until MySQL Cluster NDB 6.3.31 is released. This is a source-only release. You can obtain the GPL source code for MySQL Cluster NDB 6.3.30 from `ftp://ftp.mysql.com/pub/mysql/download/cluster_telco/mysql-5.1.39-ndb-6.3.30/'. This release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.3 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.39 (see *Note news-5-1-39::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * Added multi-threaded ordered index building capability during system restarts or node restarts, controlled by the `BuildIndexThreads' data node configuration parameter (also introduced in this release).  File: manual.info, Node: mysql-cluster-news-5-1-39-ndb-6-3-29, Next: mysql-cluster-news-5-1-39-ndb-6-3-28b, Prev: mysql-cluster-news-5-1-39-ndb-6-3-30, Up: mysql-cluster-news-6-3 17.7.4.19 Changes in MySQL Cluster NDB 6.3.29 (5.1.39-ndb-6.3.29) (15 December 2009) .................................................................................... This is a bugfix release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.3 release. This is a source-only release. You can obtain the GPL source code for MySQL Cluster NDB 6.3.29 from `ftp://ftp.mysql.com/pub/mysql/download/cluster_telco/mysql-5.1.39-ndb-6.3.29/'. This release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.3 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.39 (see *Note news-5-1-39::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * This enhanced functionality is supported for upgrades to MySQL Cluster NDB 7.0 when the *Note `NDB': mysql-cluster. engine version is 7.0.10 or later. (Bug #48528, Bug #49163) * The output from *Note `ndb_config': mysql-cluster-programs-ndb-config. `--configinfo' `--xml' now indicates, for each configuration parameter, the following restart type information: * Whether a system restart or a node restart is required when resetting that parameter; * Whether cluster nodes need to be restarted using the `--initial' option when resetting the parameter. (Bug #47366) *Bugs fixed:* * Node takeover during a system restart occurs when the REDO log for one or more data nodes is out of date, so that a node restart is invoked for that node or those nodes. If this happens while a *Note `mysqld': mysqld. process is attached to the cluster as an SQL node, the *Note `mysqld': mysqld. takes a global schema lock (a row lock), while trying to set up cluster-internal replication. However, this setup process could fail, causing the global schema lock to be held for an excessive length of time, which made the node restart hang as well. As a result, the mysqld failed to set up cluster-internal replication, which led to tables being read only, and caused one node to hang during the restart. *Note*: This issue could actually occur in MySQL Cluster NDB 7.0 only, but the fix was also applied MySQL Cluster NDB 6.3, in order to keep the two codebases in alignment. (Bug #49560) * Sending `SIGHUP' to a *Note `mysqld': mysqld. running with the `--ndbcluster' and `--log-bin' options caused the process to crash instead of refreshing its log files. (Bug #49515) * If the master data node receiving a request from a newly-started API or data node for a node ID died before the request has been handled, the management server waited (and kept a mutex) until all handling of this node failure was complete before responding to any other connections, instead of responding to other connections as soon as it was informed of the node failure (that is, it waited until it had received a NF_COMPLETEREP signal rather than a NODE_FAILREP signal). On visible effect of this misbehavior was that it caused management client commands such as SHOW and ALL STATUS to respond with unnecessary slowness in such circumstances. (Bug #49207) * When evaluating the options `--include-databases', `--include-tables', `--exclude-databases', and `--exclude-tables', the *Note `ndb_restore': mysql-cluster-programs-ndb-restore. program overwrote the result of the database-level options with the result of the table-level options rather than merging these results together, sometimes leading to unexpected and unpredictable results. As part of the fix for this problem, the semantics of these options have been clarified; because of this, the rules governing their evaluation have changed slightly. These changes be summed up as follows: * All `--include-*' and `--exclude-*' options are now evaluated from right to left in the order in which they are passed to *Note `ndb_restore': mysql-cluster-programs-ndb-restore. * All `--include-*' and `--exclude-*' options are now cumulative. * In the event of a conflict, the first (rightmost) option takes precedence. For more detailed information and examples, see *Note mysql-cluster-programs-ndb-restore::. (Bug #48907) * When performing tasks that generated large amounts of I/O (such as when using *Note `ndb_restore': mysql-cluster-programs-ndb-restore.), an internal memory buffer could overflow, causing data nodes to fail with signal 6. Subsequent analysis showed that this buffer was not actually required, so this fix removes it. (Bug #48861) * Exhaustion of send buffer memory or long signal memory caused data nodes to crash. Now an appropriate error message is provided instead when this situation occurs. (Bug #48852) * Under certain conditions, accounting of the number of free scan records in the local query handler could be incorrect, so that during node recovery or a local checkpoint operations, the LQH could find itself lacking a scan record that is expected to find, causing the node to crash. (Bug #48697) See also Bug #48564. * The creation of an ordered index on a table undergoing DDL operations could cause a data node crash under certain timing-dependent conditions. (Bug #48604) * During an LCP master takeover, when the newly elected master did not receive a `COPY_GCI' LCP protocol message but other nodes participating in the local checkpoint had received one, the new master could use an uninitialized variable, which caused it to crash. (Bug #48584) * When running many parallel scans, a local checkpoint (which performs a scan internally) could find itself not getting a scan record, which led to a data node crash. Now an extra scan record is reserved for this purpose, and a problem with obtaining the scan record returns an appropriate error (error code 489, `Too many active scans'). (Bug #48564) * During a node restart, logging was enabled on a per-fragment basis as the copying of each fragment was completed but local checkpoints were not enabled until all fragments were copied, making it possible to run out of redo log file space (*Note `NDB': mysql-cluster. error code 410) before the restart was complete. Now logging is enabled only after all fragments has been copied, just prior to enabling local checkpoints. (Bug #48474) * When employing *Note `NDB': mysql-cluster. native backup to back up and restore an empty *Note `NDB': mysql-cluster. table that used a non-sequential `AUTO_INCREMENT' value, the `AUTO_INCREMENT' value was not restored correctly. (Bug #48005) * *Note `ndb_config `--xml' `--configinfo'': mysql-cluster-programs-ndb-config. now indicates that parameters belonging in the `[SCI]', `[SCI DEFAULT]', `[SHM]', and `[SHM DEFAULT]' sections of the `config.ini' file are deprecated or experimental, as appropriate. (Bug #47365) * *Note `NDB': mysql-cluster. stores blob column data in a separate, hidden table that is not accessible from MySQL. If this table was missing for some reason (such as accidental deletion of the file corresponding to the hidden table) when making a MySQL Cluster native backup, ndb_restore crashed when attempting to restore the backup. Now in such cases, ndb_restore fails with the error message `Table TABLE_NAME has blob column (COLUMN_NAME) with missing parts table in backup' instead. (Bug #47289) * *Note `DROP DATABASE': drop-database. failed when there were stale temporary *Note `NDB': mysql-cluster. tables in the database. This situation could occur if *Note `mysqld': mysqld. crashed during execution of a *Note `DROP TABLE': drop-table. statement after the table definition had been removed from *Note `NDBCLUSTER': mysql-cluster. but before the corresponding `.ndb' file had been removed from the crashed SQL node's data directory. Now, when *Note `mysqld': mysqld. executes *Note `DROP DATABASE': drop-database, it checks for these files and removes them if there are no corresponding table definitions for them found in *Note `NDBCLUSTER': mysql-cluster. (Bug #44529) * Creating an *Note `NDB': mysql-cluster. table with an excessive number of large *Note `BIT': numeric-types. columns caused the cluster to fail. Now, an attempt to create such a table is rejected with error 791 (`Too many total bits in bitfields'). (Bug #42046) See also Bug #42047. * When a long-running transaction lasting long enough to cause Error 410 (`REDO log files overloaded') was later committed or rolled back, it could happen that *Note `NDBCLUSTER': mysql-cluster. was not able to release the space used for the REDO log, so that the error condition persisted indefinitely. The most likely cause of such transactions is a bug in the application using MySQL Cluster. This fix should handle most cases where this might occur. (Bug #36500) * Deprecation and usage information obtained from *Note `ndb_config `--configinfo'': mysql-cluster-programs-ndb-config. regarding the `PortNumber' and `ServerPort' configuration parameters was improved. (Bug #24584) * *Disk Data*: When running a write-intensive workload with a very large disk page buffer cache, CPU usage approached 100% during a local checkpoint of a cluster containing Disk Data tables. (Bug #49532) * *Disk Data*: Repeatedly creating and then dropping Disk Data tables could eventually lead to data node failures. (Bug #45794, Bug #48910) * *Disk Data*: When the `FileSystemPathUndoFiles' configuration parameter was set to an non-existent path, the data nodes shut down with the generic error code 2341 (`Internal program error'). Now in such cases, the error reported is error 2815 (`File not found'). * *Cluster Replication*: When `expire_logs_days' was set, the thread performing the purge of the log files could deadlock, causing all binary log operations to stop. (Bug #49536) * *Cluster API*: When a DML operation failed due to a uniqueness violation on an *Note `NDB': mysql-cluster. table having more than one unique index, it was difficult to determine which constraint caused the failure; it was necessary to obtain an `NdbError' object, then decode its `details' property, which in could lead to memory management issues in application code. To help solve this problem, a new API method `Ndb::getNdbErrorDetail()' is added, providing a well-formatted string containing more precise information about the index that caused the unque constraint violation. The following additional changes are also made in the NDB API: * Use of `NdbError.details' is now deprecated in favor of the new method. * The `NdbDictionary::listObjects()' method has been modified to provide more information. For more information, see `Ndb::getNdbErrorDetail()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndb-methods.html#ndb-ndb-getndberrordetail), The `NdbError' Structure (http://dev.mysql.com/doc/ndbapi/en/ndb-ndberror.html#ndb-ndberror), and `Dictionary::listObjects()' (http://dev.mysql.com/doc/ndbapi/en/ndb-dictionary-methods.html#ndb-dictionary-listobjects). (Bug #48851) * *Cluster API*: When using blobs, calling `getBlobHandle()' requires the full key to have been set using `equal()', because `getBlobHandle()' must access the key for adding blob table operations. However, if `getBlobHandle()' was called without first setting all parts of the primary key, the application using it crashed. Now, an appropriate error code is returned instead. (Bug #28116, Bug #48973)  File: manual.info, Node: mysql-cluster-news-5-1-39-ndb-6-3-28b, Next: mysql-cluster-news-5-1-39-ndb-6-3-28a, Prev: mysql-cluster-news-5-1-39-ndb-6-3-29, Up: mysql-cluster-news-6-3 17.7.4.20 Changes in MySQL Cluster NDB 6.3.28b (5.1.39-ndb-6.3.28b) (10 November 2009) ...................................................................................... This release includes a fix for Bug#48651, which was discovered in MySQL Cluster NDB 6.3.28a shortly after release. The MySQL Cluster NDB 6.3.28b release is identical in all other respects to MySQL Cluster NDB 6.3.28a. Users who have already installed MySQL Cluster NDB 6.3.28a should upgrade to MySQL Cluster NDB 6.3.28b as soon as possible; users seeking to upgrade from any other previous MySQL Cluster 6.3 release should upgrade to MySQL Cluster NDB 6.3.28b instead. This is a source-only release. You can obtain the GPL source code for MySQL Cluster NDB 6.3.28b from `http://dev.mysql.com/downloads/cluster/'. This release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.3 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.39 (see *Note news-5-1-39::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Bugs fixed:* * When the combined length of all names of tables using the *Note `NDB': mysql-cluster. storage engine was greater than or equal to 1024 bytes, issuing the `START BACKUP' command in the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client caused the cluster to crash. (Bug #48531)  File: manual.info, Node: mysql-cluster-news-5-1-39-ndb-6-3-28a, Next: mysql-cluster-news-5-1-39-ndb-6-3-28, Prev: mysql-cluster-news-5-1-39-ndb-6-3-28b, Up: mysql-cluster-news-6-3 17.7.4.21 Changes in MySQL Cluster NDB 6.3.28a (5.1.39-ndb-6.3.28a) (05 November 2009) ...................................................................................... *Important*: MySQL Cluster NDB 6.3.28a was pulled shortly after release due to Bug#48651. Users seeking to upgrade from a previous MySQL Cluster NDB 6.3 release should instead use MySQL Cluster NDB 6.3.28b, which contains a fix for this bug, in addition to all bugfixes and improvements made in MySQL Cluster NDB 6.3.28a. This release includes a fix for Bug#48531, which was discovered in MySQL Cluster NDB 6.3.28 shortly after release. The MySQL Cluster NDB 6.3.28a release is identical in all other respects to MySQL Cluster NDB 6.3.28. Users who have already installed MySQL Cluster NDB 6.3.28 should upgrade to MySQL Cluster NDB 6.3.28a as soon as possible; users seeking to upgrade from any other previous MySQL Cluster 6.3 release should upgrade to MySQL Cluster NDB 6.3.28a instead. This release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.3 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.39 (see *Note news-5-1-39::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Bugs fixed:* * When the combined length of all names of tables using the *Note `NDB': mysql-cluster. storage engine was greater than or equal to 1024 bytes, issuing the `START BACKUP' command in the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client caused the cluster to crash. (Bug #48531)  File: manual.info, Node: mysql-cluster-news-5-1-39-ndb-6-3-28, Next: mysql-cluster-news-5-1-37-ndb-6-3-27a, Prev: mysql-cluster-news-5-1-39-ndb-6-3-28a, Up: mysql-cluster-news-6-3 17.7.4.22 Changes in MySQL Cluster NDB 6.3.28 (5.1.39-ndb-6.3.28) (31 October 2009) ................................................................................... *Important*: MySQL Cluster NDB 6.3.28 and 6.3.28a were pulled shortly after being released due to Bug#48531 and Bug#48651. Users seeking to upgrade from a previous MySQL Cluster NDB 6.3 release should instead use MySQL Cluster NDB 6.3.28b, which contains fixes for these critical bugs, in addition to all bugfixes and improvements made in MySQL Cluster NDB 6.3.28. This is a bugfix release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.3 release. This release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.3 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.39 (see *Note news-5-1-39::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * *Performance*: Significant improvements in redo log handling and other file system operations can yield a considerable reduction in the time required for restarts. While actual restart times observed in a production setting will naturally vary according to database size, hardware, and other conditions, our own preliminary testing shows that these optimizations can yield startup times that are faster than those typical of previous MySQL Cluster releases by a factor of 50 or more. *Bugs fixed:* * *Important Change*: The `--with-ndb-port-base' option for `configure' did not function correctly, and has been deprecated. Attempting to use this option produces the warning `Ignoring deprecated option --with-ndb-port-base'. Beginning with MySQL Cluster NDB 7.1.0, the deprecation warning itself is removed, and the `--with-ndb-port-base' option is simply handled as an unknown and invalid option if you try to use it. (Bug #47941) See also Bug #38502. * In certain cases, performing very large inserts on `NDB' tables when using *Note `ndbmtd': mysql-cluster-programs-ndbmtd. caused the memory allocations for ordered or unique indexes (or both) to be exceeded. This could cause aborted transactions and possibly lead to data node failures. (Bug #48037) See also Bug #48113. * For *Note `UPDATE IGNORE': update. statements, batching of updates is now disabled. This is because such statements failed when batching of updates was employed if any updates violated a unique constraint, to the fact a unique constraint violation could not be handled without aborting the transaction. (Bug #48036) * Starting a data node with a very large amount of `DataMemory' (approximately 90G or more) could lead to crash of the node due to job buffer congestion. (Bug #47984) * When an *Note `UPDATE': update. statement was issued against an *Note `NDB': mysql-cluster. table where an index was used to identify rows but no data was actually changed, the *Note `NDB': mysql-cluster. storage returned zero found rows. For example, consider the table created and populated using these statements: CREATE TABLE t1 ( c1 INT NOT NULL, c2 INT NOT NULL, PRIMARY KEY(c1), KEY(c2) ) ENGINE = NDB; INSERT INTO t1 VALUES(1, 1); The following *Note `UPDATE': update. statements, even though they did not change any rows, each still matched a row, but this was reported incorrectly in both cases, as shown here: mysql> UPDATE t1 SET c2 = 1 WHERE c1 = 1; Query OK, 0 rows affected (0.00 sec) Rows matched: 0 Changed: 0 Warnings: 0 mysql> UPDATE t1 SET c1 = 1 WHERE c2 = 1; Query OK, 0 rows affected (0.00 sec) Rows matched: 0 Changed: 0 Warnings: 0 Now in such cases, the number of rows matched is correct. (In the case of each of the example *Note `UPDATE': update. statements just shown, this is displayed as Rows matched: 1, as it should be.) This issue could affect *Note `UPDATE': update. statements involving any indexed columns in *Note `NDB': mysql-cluster. tables, regardless of the type of index (including `KEY', `UNIQUE KEY', and `PRIMARY KEY') or the number of columns covered by the index. (Bug #47955) * On Solaris, shutting down a management node failed when issuing the command to do so from a client connected to a different management node. (Bug #47948) * Setting `FragmentLogFileSize' to a value greater than 256 MB led to errors when trying to read the redo log file. (Bug #47908) * *Note `SHOW CREATE TABLE': show-create-table. did not display the `AUTO_INCREMENT' value for `NDB' tables having `AUTO_INCREMENT' columns. (Bug #47865) * Under some circumstances, when a scan encountered an error early in processing by the `DBTC' kernel block (see The `DBTC' Block (http://dev.mysql.com/doc/ndbapi/en/ndb-internals-kernel-blocks-dbtc.html)), a node could crash as a result. Such errors could be caused by applications sending incorrect data, or, more rarely, by a *Note `DROP TABLE': drop-table. operation executed in parallel with a scan. (Bug #47831) * When starting a node and synchronizing tables, memory pages were allocated even for empty fragments. In certain situations, this could lead to insufficient memory. (Bug #47782) * A very small race-condition between `NODE_FAILREP' and `LQH_TRANSREQ' signals when handling node failure could lead to operations (locks) not being taken over when they should have been, and subsequently becoming stale. This could lead to node restart failures, and applications getting into endless lock-conflicts with operations that were not released until the node was restarted. (Bug #47715) See also Bug #41297. * `configure' failed to honor the `--with-zlib-dir' option when trying to build MySQL Cluster from source. (Bug #47223) * *Note `ndbd': mysql-cluster-programs-ndbd. was not built correctly when compiled using `gcc' 4.4.0. (The *Note `ndbd': mysql-cluster-programs-ndbd. binary was built, but could not be started.) (Bug #46113) * If a node failed while sending a fragmented long signal, the receiving node did not free long signal assembly resources that it had allocated for the fragments of the long signal that had already been received. (Bug #44607) * When starting a cluster with a great many tables, it was possible for MySQL client connections as well as the slave SQL thread to issue DML statements against MySQL Cluster tables before *Note `mysqld': mysqld. had finished connecting to the cluster and making all tables writeable. This resulted in `Table ... is read only' errors for clients and the Slave SQL thread. This issue is fixed by introducing the `--ndb-wait-setup' option for the MySQL server. This provides a configurable maximum amount of time that *Note `mysqld': mysqld. waits for all *Note `NDB': mysql-cluster. tables to become writeable, before enabling MySQL clients or the slave SQL thread to connect. (Bug #40679) See also Bug #46955. * When building MySQL Cluster, it was possible to configure the build using `--with-ndb-port' without supplying a port number. Now in such cases, `configure' fails with an error. (Bug #38502) See also Bug #47941. * When the MySQL server SQL mode included `STRICT_TRANS_TABLES', storage engine warnings and error codes specific to `NDB' were returned when errors occurred, instead of the MySQL server errors and error codes expected by some programming APIs (such as Connector/J) and applications. (Bug #35990) * When a copying operation exhausted the available space on a data node while copying large *Note `BLOB': blob. columns, this could lead to failure of the data node and a `Table is full' error on the SQL node which was executing the operation. Examples of such operations could include an *Note `ALTER TABLE': alter-table. that changed an *Note `INT': numeric-types. column to a *Note `BLOB': blob. column, or a bulk insert of *Note `BLOB': blob. data that failed due to running out of space or to a duplicate key error. (Bug #34583, Bug #48040) See also Bug #41674, Bug #45768. * *Replication*: When *Note `mysqlbinlog': mysqlbinlog. `--verbose' was used to read a binary log that had been written using row-based format, the output for events that updated some but not all columns of tables was not correct. (Bug #47323) * *Disk Data*: A local checkpoint of an empty fragment could cause a crash during a system restart which was based on that LCP. (Bug #47832) See also Bug #41915. * *Cluster Replication*: When using multiple active replication channels, it was sometimes possible that a node group would fail on the slave cluster, causing the slave cluster to shut down. (Bug #47935) * *Cluster Replication*: When recording a binary log using the `--ndb-log-update-as-write' and `--ndb-log-updated-only' options (both enabled by default) and later attempting to apply that binary log with *Note `mysqlbinlog': mysqlbinlog, any operations that were played back from the log but which updated only some (but not all) columns caused any columns that were not updated to be reset to their default values. (Bug #47674) See also Bug #47323, Bug #46662. * *Cluster Replication*: *Note `mysqlbinlog': mysqlbinlog. failed to apply correctly a binary log that had been recorded using `--ndb-log-update-as-write=1'. (Bug #46662) See also Bug #47323, Bug #47674. * *Cluster API*: If an NDB API program reads the same column more than once, it is possible exceed the maximum permissible message size, in which case the operation should be aborted due to NDB error 880 `Tried to read too much - too many getValue calls', however due to a change introduced in MySQL Cluster NDB 6.3.18, the check for this was not done correctly, which instead caused a data node crash. (Bug #48266) * *Cluster API*: The NDB API methods `Dictionary::listEvents()', `Dictionary::listIndexes()', `Dictionary::listObjects()', and `NdbOperation::getErrorLine()' formerly had both `const' and non-`const' variants. The non-`const' versions of these methods have been removed. In addition, the `NdbOperation::getBlobHandle()' method has been re-implemented to provide consistent internal semantics. (Bug #47798) * *Cluster API*: A duplicate read of a column caused NDB API applications to crash. (Bug #45282) * *Cluster API*: The error handling shown in the example file `ndbapi_scan.cpp' included with the MySQL Cluster distribution was incorrect. (Bug #39573) * Installation of MySQL on Windows would fail to set the correct location for the character set files, which could lead to *Note `mysqld': mysqld. and *Note `mysql': mysql. failing to initialize properly. (Bug #17270)  File: manual.info, Node: mysql-cluster-news-5-1-37-ndb-6-3-27a, Next: mysql-cluster-news-5-1-37-ndb-6-3-27, Prev: mysql-cluster-news-5-1-39-ndb-6-3-28, Up: mysql-cluster-news-6-3 17.7.4.23 Changes in MySQL Cluster NDB 6.3.27a (5.1.37-ndb-6.3.27a) (07 October 2009) ..................................................................................... This release includes a fix for Bug#47844, which was discovered in MySQL Cluster NDB 6.3.27 shortly after release. The MySQL Cluster NDB 6.3.27a release is identical in all other respects to MySQL Cluster NDB 6.3.27. Users who have already installed MySQL Cluster NDB 6.3.27 should upgrade to MySQL Cluster NDB 6.3.27a as soon as possible; users seeking to upgrade from MySQL Cluster NDB 6.3.26 or another previous MySQL Cluster 6.3 release should upgrade to MySQL Cluster NDB 6.3.27a instead. This is a source-only release. You can obtain the GPL source code for MySQL Cluster NDB 6.3.27a from `ftp://ftp.mysql.com/pub/mysql/download/cluster_telco/mysql-5.1.37-ndb-6.3.27a/'. This release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.3 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.37 (see *Note news-5-1-37::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Bugs fixed:* * The disconnection of an API or SQL node having a node ID greater than 49 caused a forced shutdown of the cluster. (Bug #47844) * The error message text for *Note `NDB': mysql-cluster. error code 410 (`REDO log files overloaded...') was truncated. (Bug #23662)  File: manual.info, Node: mysql-cluster-news-5-1-37-ndb-6-3-27, Next: mysql-cluster-news-5-1-35-ndb-6-3-26, Prev: mysql-cluster-news-5-1-37-ndb-6-3-27a, Up: mysql-cluster-news-6-3 17.7.4.24 Changes in MySQL Cluster NDB 6.3.27 (5.1.37-ndb-6.3.27) (30 September 2009) ..................................................................................... *Important*: MySQL Cluster NDB 6.3.27 was pulled shortly after release due to Bug#47844. Users seeking to upgrade from a previous MySQL Cluster NDB 6.3 release should instead use MySQL Cluster NDB 6.3.27a, which contains a fix for this bug, in addition to all bugfixes and improvements made in MySQL Cluster NDB 6.3.27. This is a bugfix release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.3 release. This release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.3 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.37 (see *Note news-5-1-37::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * *Disk Data*: Two new columns have been added to the output of *Note `ndb_desc': mysql-cluster-programs-ndb-desc. to make it possible to determine how much of the disk space allocated to a given table or fragment remains free. (This information is not available from the *Note `INFORMATION_SCHEMA.FILES': files-table. table, since the *Note `FILES': files-table. table applies only to Disk Data files.) For more information, see *Note mysql-cluster-programs-ndb-desc::. (Bug #47131) *Bugs fixed:* * *Cluster Replication*: *Important Change*: In a MySQL Cluster acting as a replication slave and having multiple SQL nodes, only the SQL node receiving events directly from the master recorded DDL statements in its binary logs unless this SQL node also had binary logging enabled; otherwise, other SQL nodes in the slave cluster failed to log DDL statements, regardless of their individual `--log-bin' settings. The fix for this issue aligns binary logging of DDL statements with that of DML statements. In particular, you should take note of the following: * DDL and DML statements on the master cluster are logged with the server ID of the server that actually writes the log. * DDL and DML statements on the master cluster are logged by any attached *Note `mysqld': mysqld. that has binary logging enabled. * Replicated DDL and DML statements on the slave are logged by any attached mysqld that has both `--log-bin' and `--log-slave-updates' enabled. * Replicated DDL and DML statements are logged with the server ID of the original (master) MySQL server by any attached *Note `mysqld': mysqld. that has both `--log-bin' and `--log-slave-updates' enabled. Affect on upgrades When upgrading from a previous MySQL CLuster release, you should perform either one of the following: 1. Upgrade servers that are performing binary logging before those that are not; do not perform any DDL on `old' SQL nodes until all SQL nodes have been upgraded. 2. Make sure that `--log-slave-updates' is enabled on all SQL nodes performing binary logging prior to the upgrade, so that all DDL is captured. *Note*: Logging of DML statements was not affected by this issue. (Bug #45756) * *Note `mysqld': mysqld. allocated an excessively large buffer for handling *Note `BLOB': blob. values due to overestimating their size. (For each row, enough space was allocated to accommodate _every_ *Note `BLOB': blob. or *Note `TEXT': blob. column value in the result set.) This could adversely affect performance when using tables containing *Note `BLOB': blob. or *Note `TEXT': blob. columns; in a few extreme cases, this issue could also cause the host system to run out of memory unexpectedly. (Bug #47574) See also Bug #47572, Bug #47573. * `NDBCLUSTER' uses a dynamically-allocated buffer to store *Note `BLOB': blob. or *Note `TEXT': blob. column data that is read from rows in MySQL Cluster tables. When an instance of the `NDBCLUSTER' table handler was recycled (this can happen due to table definition cache pressure or to operations such as *Note `FLUSH TABLES': flush. or *Note `ALTER TABLE': alter-table.), if the last row read contained blobs of zero length, the buffer was not freed, even though the reference to it was lost. This resulted in a memory leak. For example, consider the table defined and populated as shown here: CREATE TABLE t (a INT PRIMARY KEY, b LONGTEXT) ENGINE=NDB; INSERT INTO t VALUES (1, REPEAT('F', 20000)); INSERT INTO t VALUES (2, ''); Now execute repeatedly a *Note `SELECT': select. on this table, such that the zero-length *Note `LONGTEXT': blob. row is last, followed by a *Note `FLUSH TABLES': flush. statement (which forces the handler object to be re-used), as shown here: SELECT a, length(b) FROM bl ORDER BY a; FLUSH TABLES; Prior to the fix, this resulted in a memory leak proportional to the size of the stored *Note `LONGTEXT': blob. value each time these two statements were executed. (Bug #47573) See also Bug #47572, Bug #47574. * Large transactions involving joins between tables containing *Note `BLOB': blob. columns used excessive memory. (Bug #47572) See also Bug #47573, Bug #47574. * A variable was left uninitialized while a data node copied data from its peers as part of its startup routine; if the starting node died during this phase, this could lead a crash of the cluster when the node was later restarted. (Bug #47505) * When a data node restarts, it first runs the redo log until reaching the latest restorable global checkpoint; after this it scans the remainder of the redo log file, searching for entries that should be invalidated so they are not used in any subsequent restarts. (It is possible, for example, if restoring GCI number 25, that there might be entries belonging to GCI 26 in the redo log.) However, under certain rare conditions, during the invalidation process, the redo log files themselves were not always closed while scanning ahead in the redo log. In rare cases, this could lead to `MaxNoOfOpenFiles' being exceeded, causing a the data node to crash. (Bug #47171) * For very large values of `MaxNoOfTables' + `MaxNoOfAttributes', the calculation for `StringMemory' could overflow when creating large numbers of tables, leading to *Note `NDB': mysql-cluster. error 773 (`Out of string memory, please modify StringMemory config parameter'), even when `StringMemory' was set to `100' (100 percent). (Bug #47170) * The default value for the `StringMemory' configuration parameter, unlike other MySQL Cluster configuration parameters, was not set in `ndb/src/mgmsrv/ConfigInfo.cpp'. (Bug #47166) * Signals from a failed API node could be received after an `API_FAILREQ' signal (see Operations and Signals (http://dev.mysql.com/doc/ndbapi/en/ndb-internals-ndb-protocol-operations-signals.html)) has been received from that node, which could result in invalid states for processing subsequent signals. Now, all pending signals from a failing API node are processed before any `API_FAILREQ' signal is received. (Bug #47039) See also Bug #44607. * Using triggers on *Note `NDB': mysql-cluster. tables caused `ndb_autoincrement_prefetch_sz' to be treated as having the NDB kernel's internal default value (32) and the value for this variable as set on the cluster's SQL nodes to be ignored. (Bug #46712) * Running an *Note `ALTER TABLE': alter-table. statement while an *Note `NDB': mysql-cluster. backup was in progress caused *Note `mysqld': mysqld. to crash. (Bug #44695) * When performing auto-discovery of tables on individual SQL nodes, `NDBCLUSTER' attempted to overwrite existing `MyISAM' `.frm' files and corrupted them. Workaround In the *Note `mysql': mysql. client, create a new table (`t2') with same definition as the corrupted table (`t1'). Use your system shell or file manager to rename the old `.MYD' file to the new file name (for example, `mv t1.MYD t2.MYD'). In the *Note `mysql': mysql. client, repair the new table, drop the old one, and rename the new table using the old file name (for example, *Note `RENAME TABLE t2 TO t1': rename-table.). (Bug #42614) * Running *Note `ndb_restore': mysql-cluster-programs-ndb-restore. with the `--print' or `--print_log' option could cause it to crash. (Bug #40428, Bug #33040) * An insert on an *Note `NDB': mysql-cluster. table was not always flushed properly before performing a scan. One way in which this issue could manifest was that `LAST_INSERT_ID()' sometimes failed to return correct values when using a trigger on an *Note `NDB': mysql-cluster. table. (Bug #38034) * When a data node received a `TAKE_OVERTCCONF' signal from the master before that node had received a `NODE_FAILREP', a race condition could in theory result. (Bug #37688) See also Bug #25364, Bug #28717. * Some joins on large *Note `NDB': mysql-cluster. tables having *Note `TEXT': blob. or *Note `BLOB': blob. columns could cause *Note `mysqld': mysqld. processes to leak memory. The joins did not need to reference the *Note `TEXT': blob. or *Note `BLOB': blob. columns directly for this issue to occur. (Bug #36701) * On Mac OS X 10.5, commands entered in the management client failed and sometimes caused the client to hang, although management client commands invoked using the `--execute' (or `-e') option from the system shell worked normally. For example, the following command failed with an error and hung until killed manually, as shown here: ndb_mgm> SHOW `Warning, event thread startup failed, degraded printouts as result, errno=36' ^C However, the same management client command, invoked from the system shell as shown here, worked correctly: shell> ndb_mgm -e "SHOW" (Bug #35751) See also Bug #34438. * *Replication*: In some cases, a *Note `STOP SLAVE': stop-slave. statement could cause the replication slave to crash. This issue was specific to MySQL on Windows or Macintosh platforms. (Bug #45238, Bug #45242, Bug #45243, Bug #46013, Bug #46014, Bug #46030) See also Bug #40796. * *Disk Data*: Calculation of free space for Disk Data table fragments was sometimes done incorrectly. This could lead to unnecessary allocation of new extents even when sufficient space was available in existing ones for inserted data. In some cases, this might also lead to crashes when restarting data nodes. *Note*: This miscalculation was not reflected in the contents of the *Note `INFORMATION_SCHEMA.FILES': files-table. table, as it applied to extents allocated to a fragment, and not to a file. (Bug #47072) * *Cluster API*: In some circumstances, if an API node encountered a data node failure between the creation of a transaction and the start of a scan using that transaction, then any subsequent calls to `startTransaction()' and `closeTransaction()' could cause the same transaction to be started and closed repeatedly. (Bug #47329) * *Cluster API*: Performing multiple operations using the same primary key within the same `NdbTransaction::execute()' call could lead to a data node crash. *Note*: This fix does not make change the fact that performing multiple operations using the same primary key within the same `execute()' is not supported; because there is no way to determine the order of such operations, the result of such combined operations remains undefined. (Bug #44065) See also Bug #44015. * *API*: The fix for Bug#24507 could lead in some cases to client application failures due to a race condition. Now the server waits for the `dummy' thread to return before exiting, thus making sure that only one thread can initialize the POSIX threads library. (Bug #42850)  File: manual.info, Node: mysql-cluster-news-5-1-35-ndb-6-3-26, Next: mysql-cluster-news-5-1-34-ndb-6-3-25, Prev: mysql-cluster-news-5-1-37-ndb-6-3-27, Up: mysql-cluster-news-6-3 17.7.4.25 Changes in MySQL Cluster NDB 6.3.26 (5.1.35-ndb-6.3.26) (26 August 2009) .................................................................................. This is a bugfix release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.3 release. This release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.3 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.35 (see *Note news-5-1-35::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * On Solaris platforms, the MySQL Cluster management server and NDB API applications now use `CLOCK_REALTIME' as the default clock. (Bug #46183) * A new option `--exclude-missing-columns' has been added for the *Note `ndb_restore': mysql-cluster-programs-ndb-restore. program. In the event that any tables in the database or databases being restored to have fewer columns than the same-named tables in the backup, the extra columns in the backup's version of the tables are ignored. For more information, see *Note mysql-cluster-programs-ndb-restore::. (Bug #43139) * *Note*: This issue, originally resolved in MySQL 5.1.16, re-occurred due to a later (unrelated) change. The fix has been re-applied. (Bug #25984) *Bugs fixed:* * Restarting the cluster following a local checkpoint and an online *Note `ALTER TABLE': alter-table. on a non-empty table caused data nodes to crash. (Bug #46651) * Full table scans failed to execute when the cluster contained more than 21 table fragments. *Note*: The number of table fragments in the cluster can be calculated as the number of data nodes, times 8 (that is, times the value of the internal constant `MAX_FRAG_PER_NODE'), divided by the number of replicas. Thus, when `NoOfReplicas = 1' at least 3 data nodes were required to trigger this issue, and when `NoOfReplicas = 2' at least 4 data nodes were required to do so. (Bug #46490) * Killing MySQL Cluster nodes immediately following a local checkpoint could lead to a crash of the cluster when later attempting to perform a system restart. The exact sequence of events causing this issue was as follows: 1. Local checkpoint occurs. 2. Immediately following the LCP, kill the master data node. 3. Kill the remaining data nodes within a few seconds of killing the master. 4. Attempt to restart the cluster. (Bug #46412) * Ending a line in the `config.ini' file with an extra semicolon character (`;') caused reading the file to fail with a parsing error. (Bug #46242) * When combining an index scan and a delete with a primary key delete, the index scan and delete failed to initialize a flag properly. This could in rare circumstances cause a data node to crash. (Bug #46069) * *Note `OPTIMIZE TABLE': optimize-table. on an *Note `NDB': mysql-cluster. table could in some cases cause SQL and data nodes to crash. This issue was observed with both *Note `ndbd': mysql-cluster-programs-ndbd. and *Note `ndbmtd': mysql-cluster-programs-ndbmtd. (Bug #45971) * The `AutoReconnect' configuration parameter for API nodes (including SQL nodes) has been added. This is intended to prevent API nodes from re-using allocated node IDs during cluster restarts. For more information, see *Note mysql-cluster-api-definition::. This fix also introduces two new methods of the NDB API `Ndb_cluster_connection' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndb-cluster-connection.html#ndb-ndb-cluster-connection) class: `set_auto_reconnect()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndb-cluster-connection-methods.html#ndb-ndb-cluster-connection-set-auto-reconnect) and `get_auto_reconnect()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndb-cluster-connection-methods.html#ndb-ndb-cluster-connection-get-auto-reconnect). (Bug #45921) * The signals used by *Note `ndb_restore': mysql-cluster-programs-ndb-restore. to send progress information about backups to the cluster log accessed the cluster transporter without using any locks. Because of this, it was theoretically possible that these signals could be interefered with by heartbeat signals if both were sent at the same time, causing the *Note `ndb_restore': mysql-cluster-programs-ndb-restore. messages to be corrupted. (Bug #45646) * Problems could arise when using *Note `VARCHAR': char. columns whose size was greater than 341 characters and which used the `utf8_unicode_ci' collation. In some cases, this combination of conditions could cause certain queries and *Note `OPTIMIZE TABLE': optimize-table. statements to crash *Note `mysqld': mysqld. (Bug #45053) * An internal NDB API buffer was not properly initialized. (Bug #44977) * When a data node had written its GCI marker to the first page of a megabyte, and that node was later killed during restart after having processed that page (marker) but before completing a LCP, the data node could fail with file system errors. (Bug #44952) See also Bug #42564, Bug #44291. * The warning message `Possible bug in Dbdih::execBLOCK_COMMIT_ORD ...' could sometimes appear in the cluster log. This warning is obsolete, and has been removed. (Bug #44563) * In some cases, *Note `OPTIMIZE TABLE': optimize-table. on an *Note `NDB': mysql-cluster. table did not free any `DataMemory'. (Bug #43683) * If the cluster crashed during the execution of a *Note `CREATE LOGFILE GROUP': create-logfile-group. statement, the cluster could not be restarted afterward. (Bug #36702) See also Bug #34102. * *Disk Data*: *Partitioning*: An *Note `NDB': mysql-cluster. table created with a very large value for the `MAX_ROWS' option could--if this table was dropped and a new table with fewer partitions, but having the same table ID, was created--cause *Note `ndbd': mysql-cluster-programs-ndbd. to crash when performing a system restart. This was because the server attempted to examine each partition whether or not it actually existed. (Bug #45154) See also Bug #58638. * *Disk Data*: If the value set in the `config.ini' file for `FileSystemPathDD', `FileSystemPathDataFiles', or `FileSystemPathUndoFiles' was identical to the value set for `FileSystemPath', that parameter was ignored when starting the data node with `--initial' option. As a result, the Disk Data files in the corresponding directory were not removed when performing an initial start of the affected data node or data nodes. (Bug #46243) * *Disk Data*: During a checkpoint, restore points are created for both the on-disk and in-memory parts of a Disk Data table. Under certain rare conditions, the in-memory restore point could include or exclude a row that should have been in the snapshot. This would later lead to a crash during or following recovery. (Bug #41915) See also Bug #47832.  File: manual.info, Node: mysql-cluster-news-5-1-34-ndb-6-3-25, Next: mysql-cluster-news-5-1-32-ndb-6-3-24, Prev: mysql-cluster-news-5-1-35-ndb-6-3-26, Up: mysql-cluster-news-6-3 17.7.4.26 Changes in MySQL Cluster NDB 6.3.25 (5.1.34-ndb-6.3.25) (25 May 2009) ............................................................................... This is a bugfix release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.3 release. This release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.3 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.34 (see *Note news-5-1-34::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * Two new server status variables `Ndb_scan_count' and `Ndb_pruned_scan_count' have been introduced. `Ndb_scan_count' gives the number of scans executed since the cluster was last started. `Ndb_pruned_scan_count' gives the number of scans for which *Note `NDBCLUSTER': mysql-cluster. was able to use partition pruning. Together, these variables can be used to help determine in the MySQL server whether table scans are pruned by *Note `NDBCLUSTER': mysql-cluster. (Bug #44153) * The *Note `ndb_config': mysql-cluster-programs-ndb-config. utility program can now provide an offline dump of all MySQL Cluster configuration parameters including information such as default and permitted values, brief description, and applicable section of the `config.ini' file. A dump in text format is produced when running *Note `ndb_config': mysql-cluster-programs-ndb-config. with the new `--configinfo' option, and in XML format when the options `--configinfo --xml' are used together. For more information and examples, see *Note mysql-cluster-programs-ndb-config::. *Bugs fixed:* * *Important Change*: *Partitioning*: User-defined partitioning of an *Note `NDBCLUSTER': mysql-cluster. table without any primary key sometimes failed, and could cause *Note `mysqld': mysqld. to crash. Now, if you wish to create an *Note `NDBCLUSTER': mysql-cluster. table with user-defined partitioning, the table must have an explicit primary key, and all columns listed in the partitioning expression must be part of the primary key. The hidden primary key used by the *Note `NDBCLUSTER': mysql-cluster. storage engine is not sufficient for this purpose. However, if the list of columns is empty (that is, the table is defined using `PARTITION BY [LINEAR] KEY()'), then no explicit primary key is required. This change does not effect the partitioning of tables using any storage engine other than *Note `NDBCLUSTER': mysql-cluster. (Bug #40709) * *Important Change*: Previously, the configuration parameter `NoOfReplicas' had no default value. Now the default for `NoOfReplicas' is 2, which is the recommended value in most settings. (Bug #44746) * *Packaging*: The `pkg' installer for MySQL Cluster on Solaris did not perform a complete installation due to an invalid directory reference in the postinstall script. (Bug #41998) * When *Note `ndb_config': mysql-cluster-programs-ndb-config. could not find the file referenced by the `--config-file' option, it tried to read `my.cnf' instead, then failed with a misleading error message. (Bug #44846) * When a data node was down so long that its most recent local checkpoint depended on a global checkpoint that was no longer restorable, it was possible for it to be unable to use optimized node recovery when being restarted later. (Bug #44844) See also Bug #26913. * *Note `ndb_config `--xml'': mysql-cluster-programs-ndb-config. did not output any entries for the `HostName' parameter. In addition, the default listed for `MaxNoOfFiles' was outside the permitted range of values. (Bug #44749) See also Bug #44685, Bug #44746. * The output of *Note `ndb_config `--xml'': mysql-cluster-programs-ndb-config. did not provide information about all sections of the configuration file. (Bug #44685) See also Bug #44746, Bug #44749. * Inspection of the code revealed that several assignment operators (`=') were used in place of comparison operators (`==') in `DbdihMain.cpp'. (Bug #44567) See also Bug #44570. * It was possible for NDB API applications to insert corrupt data into the database, which could subquently lead to data node crashes. Now, stricter checking is enforced on input data for inserts and updates. (Bug #44132) * *Note `ndb_restore': mysql-cluster-programs-ndb-restore. failed when trying to restore data on a big-endian machine from a backup file created on a little-endian machine. (Bug #44069) * The file `ndberror.c' contained a C++-style comment, which caused builds to fail with some C compilers. (Bug #44036) * When trying to use a data node with an older version of the management server, the data node crashed on startup. (Bug #43699) * In some cases, data node restarts during a system restart could fail due to insufficient redo log space. (Bug #43156) * *Note `NDBCLUSTER': mysql-cluster. did not build correctly on Solaris 9 platforms. (Bug #39080) See also Bug #39036, Bug #39038. * *Note `ndb_restore `--print_data'': mysql-cluster-programs-ndb-restore. did not handle *Note `DECIMAL': numeric-types. columns correctly. (Bug #37171) * The output of *Note `ndbd `--help'': mysql-cluster-programs-ndbd. did not provide clear information about the program's `--initial' and `--initial-start' options. (Bug #28905) * It was theoretically possible for the value of a nonexistent column to be read as `NULL', rather than causing an error. (Bug #27843) * *Disk Data*: This fix supercedes and improves on an earlier fix made for this bug in MySQL 5.1.18. (Bug #24521) * *Cluster Replication*: A failure when setting up replication events could lead to subsequent data node failures. (Bug #44915)  File: manual.info, Node: mysql-cluster-news-5-1-32-ndb-6-3-24, Next: mysql-cluster-news-5-1-32-ndb-6-3-23, Prev: mysql-cluster-news-5-1-34-ndb-6-3-25, Up: mysql-cluster-news-6-3 17.7.4.27 Changes in MySQL Cluster NDB 6.3.24 (5.1.32-ndb-6.3.24) (09 April 2009) ................................................................................. This is a bugfix release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.3 release. This is a source-only release. You can obtain the GPL source code for MySQL Cluster NDB 6.3.24 from `ftp://ftp.mysql.com/pub/mysql/download/cluster_telco/mysql-5.1.32-ndb-6.3.24/'. This release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.3 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.32 (see *Note news-5-1-32::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Bugs fixed:* * *Cluster Replication*: If data node failed during an event creation operation, there was a slight risk that a surviving data node could send an invalid table reference back to NDB, causing the operation to fail with a false Error 723 (`No such table'). This could take place when a data node failed as a *Note `mysqld': mysqld. process was setting up MySQL Cluster Replication. (Bug #43754) * *Cluster API*: Partition pruning did not work correctly for queries involving multiple range scans. As part of the fix for this issue, several improvements have been made in the NDB API, including the addition of a new `NdbScanOperation::getPruned()' method, a new variant of `NdbIndexScanOperation::setBound()', and a new `PartitionSpec' data structure. (Bug #37934) * `TransactionDeadlockDetectionTimeout' values less than 100 were treated as 100. This could cause scans to time out unexpectedly. (Bug #44099) * A race condition could occur when a data node failed to restart just before being included in the next global checkpoint. This could cause other data nodes to fail. (Bug #43888) * `TimeBetweenLocalCheckpoints' was measured from the end of one local checkpoint to the beginning of the next, rather than from the beginning of one LCP to the beginning of the next. This meant that the time spent performing the LCP was not taken into account when determining the `TimeBetweenLocalCheckpoints' interval, so that LCPs were not started often enough, possibly causing data nodes to run out of redo log space prematurely. (Bug #43567) * Using indexes containing variable-sized columns could lead to internal errors when the indexes were being built. (Bug #43226) * When a data node process had been killed after allocating a node ID, but before making contact with any other data node processes, it was not possible to restart it due to a node ID allocation failure. This issue could effect either *Note `ndbd': mysql-cluster-programs-ndbd. or *Note `ndbmtd': mysql-cluster-programs-ndbmtd. processes. (Bug #43224) This regression was introduced by Bug #42973. * Some queries using combinations of logical and comparison operators on an indexed column in the `WHERE' clause could fail with the error `Got error 4541 'IndexBound has no bound information' from NDBCLUSTER'. (Bug #42857) * *Note `ndb_restore': mysql-cluster-programs-ndb-restore. crashed when trying to restore a backup made to a MySQL Cluster running on a platform having different endianness from that on which the original backup was taken. (Bug #39540) * When aborting an operation involving both an insert and a delete, the insert and delete were aborted separately. This was because the transaction coordinator did not know that the operations affected on same row, and, in the case of a committed-read (tuple or index) scan, the abort of the insert was performed first, then the row was examined after the insert was aborted but before the delete was aborted. In some cases, this would leave the row in a inconsistent state. This could occur when a local checkpoint was performed during a backup. This issue did not affect primary ley operations or scans that used locks (these are serialized). After this fix, for ordered indexes, all operations that follow the operation to be aborted are now also aborted. * *Disk Data*: When a log file group had an undo log file whose size was too small, restarting data nodes failed with `Read underflow' errors. As a result of this fix, the minimum permitted `INTIAL_SIZE' for an undo log file is now `1M' (1 megabyte). (Bug #29574) * *Cluster Replication*: When creating or altering a table an `NdbEventOperation' is created by the *Note `mysqld': mysqld. process to monitor the table for subsequent logging in the binlog. If this happened during a node restart there was a chance that the reference count on this event operation object could be incorrect, which could lead to an assert in debug MySQL Cluster builds. (Bug #43752) * *Cluster API*: If the largest offset of a `RecordSpecification' used for an `NdbRecord' object was for the `NULL' bits (and thus not a column), this offset was not taken into account when calculating the size used for the `RecordSpecification'. This meant that the space for the `NULL' bits could be overwritten by key or other information. (Bug #43891) * *Cluster API*: *Note `BIT': numeric-types. columns created using the native NDB API format that were not created as nullable could still sometimes be overwritten, or cause other columns to be overwritten. This issue did not effect tables having *Note `BIT': numeric-types. columns created using the mysqld format (always used by MySQL Cluster SQL nodes). (Bug #43802) * *Cluster API*: The default `NdbRecord' structures created by `NdbDictionary' could have overlapping null bits and data fields. (Bug #43590) * *Cluster API*: When performing insert or write operations, `NdbRecord' permits key columns to be specified in both the key record and in the attribute record. Only one key column value for each key column should be sent to the NDB kernel, but this was not guaranteed. This is now ensured as follows: For insert and write operations, key column values are taken from the key record; for scan takeover update operations, key column values are taken from the attribute record. (Bug #42238) * *Cluster API*: Ordered index scans using `NdbRecord' formerly expressed a `BoundEQ' range as separate lower and upper bounds, resulting in 2 copies of the column values being sent to the NDB kernel. Now, when a range is specified by `NdbScanOperation::setBound()', the passed pointers, key lengths, and inclusive bits are compared, and only one copy of the equal key columns is sent to the kernel. This makes such operations more efficient, as half the amount of `KeyInfo' is now sent for a `BoundEQ' range as before. (Bug #38793)  File: manual.info, Node: mysql-cluster-news-5-1-32-ndb-6-3-23, Next: mysql-cluster-news-5-1-31-ndb-6-3-22, Prev: mysql-cluster-news-5-1-32-ndb-6-3-24, Up: mysql-cluster-news-6-3 17.7.4.28 Changes in MySQL Cluster NDB 6.3.23 (5.1.32-ndb-6.3.23) (24 February 2009) .................................................................................... This is a bugfix release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.3 release. This is a source-only release. You can obtain the GPL source code for MySQL Cluster NDB 6.3.23 from `ftp://ftp.mysql.com/pub/mysql/download/cluster_telco/mysql-5.1.32-ndb-6.3.23/'. This release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.3 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.32 (see *Note news-5-1-32::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * *Important Change*: *Replication*: *Note `RESET MASTER': reset-master. and *Note `RESET SLAVE': reset-slave. now reset the values shown for `Last_IO_Error', `Last_IO_Errno', `Last_SQL_Error', and `Last_SQL_Errno' in the output of *Note `SHOW SLAVE STATUS': show-slave-status. (Bug #34654) See also Bug #44270. * A new data node configuration parameter `MaxLCPStartDelay' has been introduced to facilitate parallel node recovery by causing a local checkpoint to be delayed while recovering nodes are synchronizing data dictionaries and other meta-information. For more information about this parameter, see *Note mysql-cluster-ndbd-definition::. (Bug #43053) *Bugs fixed:* * *Performance*: Updates of the `SYSTAB_0' system table to obtain a unique identifier did not use transaction hints for tables having no primary key. In such cases the NDB kernel used a cache size of 1. This meant that each insert into a table not having a primary key required an update of the corresponding `SYSTAB_0' entry, creating a potential performance bottleneck. With this fix, inserts on `NDB' tables without primary keys can be under some conditions be performed up to 100% faster than previously. (Bug #39268) * *Packaging*: Packages for MySQL Cluster were missing the `libndbclient.so' and `libndbclient.a' files. (Bug #42278) * *Partitioning*: Executing `ALTER TABLE ... REORGANIZE PARTITION' on an *Note `NDBCLUSTER': mysql-cluster. table having only one partition caused *Note `mysqld': mysqld. to crash. (Bug #41945) See also Bug #40389. * Backup IDs greater than 2^31 were not handled correctly, causing negative values to be used in backup directory names and printouts. (Bug #43042) * When using *Note `ndbmtd': mysql-cluster-programs-ndbmtd, NDB kernel threads could hang while trying to start the data nodes with `LockPagesInMainMemory' set to 1. (Bug #43021) * When using multiple management servers and starting several API nodes (possibly including one or more SQL nodes) whose connectstrings listed the management servers in different order, it was possible for 2 API nodes to be assigned the same node ID. When this happened it was possible for an API node not to get fully connected, consequently producing a number of errors whose cause was not easily recognizable. (Bug #42973) * *Note `ndb_error_reporter': mysql-cluster-programs-ndb-error-reporter. worked correctly only with GNU `tar'. (With other versions of `tar', it produced empty archives.) (Bug #42753) * Triggers on *Note `NDBCLUSTER': mysql-cluster. tables caused such tables to become locked. (Bug #42751) See also Bug #16229, Bug #18135. * Given a MySQL Cluster containing no data (that is, whose data nodes had all been started using `--initial', and into which no data had yet been imported) and having an empty backup directory, executing `START BACKUP' with a user-specified backup ID caused the data nodes to crash. (Bug #41031) * In some cases, *Note `NDB': mysql-cluster. did not check correctly whether tables had changed before trying to use the query cache. This could result in a crash of the debug MySQL server. (Bug #40464) * *Disk Data*: It was not possible to add an in-memory column online to a table that used a table-level or column-level `STORAGE DISK' option. The same issue prevented `ALTER ONLINE TABLE ... REORGANIZE PARTITION' from working on Disk Data tables. (Bug #42549) * *Disk Data*: Creating a Disk Data tablespace with a very large extent size caused the data nodes to fail. The issue was observed when using extent sizes of 100 MB and larger. (Bug #39096) * *Disk Data*: Trying to execute a *Note `CREATE LOGFILE GROUP': create-logfile-group. statement using a value greater than `150M' for `UNDO_BUFFER_SIZE' caused data nodes to crash. As a result of this fix, the upper limit for `UNDO_BUFFER_SIZE' is now `600M'; attempting to set a higher value now fails gracefully with an error. (Bug #34102) See also Bug #36702. * *Disk Data*: When attempting to create a tablespace that already existed, the error message returned was `Table or index with given name already exists'. (Bug #32662) * *Disk Data*: Using a path or filename longer than 128 characters for Disk Data undo log files and tablespace data files caused a number of issues, including failures of *Note `CREATE LOGFILE GROUP': create-logfile-group, *Note `ALTER LOGFILE GROUP': alter-logfile-group, *Note `CREATE TABLESPACE': create-tablespace, and *Note `ALTER TABLESPACE': alter-tablespace. statements, as well as crashes of management nodes and data nodes. With this fix, the maximum length for path and file names used for Disk Data undo log files and tablespace data files is now the same as the maximum for the operating system. (Bug #31769, Bug #31770, Bug #31772) * *Disk Data*: Attempting to perform a system restart of the cluster where there existed a logfile group without and undo log files caused the data nodes to crash. *Note*: While issuing a *Note `CREATE LOGFILE GROUP': create-logfile-group. statement without an `ADD UNDOFILE' option fails with an error in the MySQL server, this situation could arise if an SQL node failed during the execution of a valid *Note `CREATE LOGFILE GROUP': create-logfile-group. statement; it is also possible to create a logfile group without any undo log files using the NDB API. (Bug #17614) * *Cluster Replication*: Being disconnected from the cluster while setting up the binary log caused *Note `mysqld': mysqld. to hang or crash. (Bug #43045) * *Cluster Replication*: Primary key updates on *Note `MyISAM': myisam-storage-engine. and *Note `InnoDB': innodb-storage-engine. tables failed to replicate to *Note `NDBCLUSTER': mysql-cluster. tables. (Bug #42921) * *Cluster API*: Some error messages from *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. contained newline (`\n') characters. This could break the MGM API protocol, which uses the newline as a line separator. (Bug #43104) * *Cluster API*: When using an ordered index scan without putting all key columns in the read mask, this invalid use of the NDB API went undetected, which resulted in the use of uninitialized memory. (Bug #42591)  File: manual.info, Node: mysql-cluster-news-5-1-31-ndb-6-3-22, Next: mysql-cluster-news-5-1-31-ndb-6-3-21, Prev: mysql-cluster-news-5-1-32-ndb-6-3-23, Up: mysql-cluster-news-6-3 17.7.4.29 Changes in MySQL Cluster NDB 6.3.22 (5.1.31-ndb-6.3.22) (09 February 2009) .................................................................................... This is a bugfix release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.3 release. This is a source-only release. You can obtain the GPL source code for MySQL Cluster NDB 6.3.22 from `ftp://ftp.mysql.com/pub/mysql/download/cluster_telco/mysql-5.1.31-ndb-6.3.22/'. This release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.3 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.31 (see *Note news-5-1-31::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * New options are introduced for *Note `ndb_restore': mysql-cluster-programs-ndb-restore. for determining which tables or databases should be restored: * `--include-tables' and `--include-databases' can be used to restore specific tables or databases. * `--exclude-tables' and `--exclude-databases' can be used to exclude the specified tables or databases from being restored. For more information about these options, see *Note mysql-cluster-programs-ndb-restore::. (Bug #40429) *Bugs fixed:* * When performing more than 32 index or tuple scans on a single fragment, the scans could be left hanging. This caused unnecessary timeouts, and in addition could possibly lead to a hang of an LCP. (Bug #42559) * A data node failure that occurred between calls to `NdbIndexScanOperation::readTuples(SF_OrderBy)' and `NdbTransaction::execute()' was not correctly handled; a subsequent call to `nextResult()' caused a null pointer to be deferenced, leading to a segfault in *Note `mysqld': mysqld. (Bug #42545) * Issuing `SHOW GLOBAL STATUS LIKE 'NDB%'' before *Note `mysqld': mysqld. had connected to the cluster caused a segmentation fault. (Bug #42458) * Data node failures that occurred before all data nodes had connected to the cluster were not handled correctly, leading to additional data node failures. (Bug #42422) * When a cluster backup failed with Error 1304 (Node NODE_ID1: Backup request from NODE_ID2 failed to start), no clear reason for the failure was provided. As part of this fix, MySQL Cluster now retries backups in the event of sequence errors. (Bug #42354) See also Bug #22698. * Issuing *Note `SHOW ENGINE NDBCLUSTER STATUS': show-engine. on an SQL node before the management server had connected to the cluster caused *Note `mysqld': mysqld. to crash. (Bug #42264)  File: manual.info, Node: mysql-cluster-news-5-1-31-ndb-6-3-21, Next: mysql-cluster-news-5-1-30-ndb-6-3-20, Prev: mysql-cluster-news-5-1-31-ndb-6-3-22, Up: mysql-cluster-news-6-3 17.7.4.30 Changes in MySQL Cluster NDB 6.3.21 (5.1.31-ndb-6.3.21) (19 January 2009) ................................................................................... This is a bugfix release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.3 release. *Note*: MySQL Cluster NDB 6.3.21 was withdrawn due to issues discovered after its release. This release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.3 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.31 (see *Note news-5-1-31::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * *Important Change*: Formerly, when the management server failed to create a transporter for a data node connection, `net_write_timeout' seconds elapsed before the data node was actually permitted to disconnect. Now in such cases the disconnection occurs immediately. (Bug #41965) See also Bug #41713. * It is now possible while in Single User Mode to restart all data nodes using `ALL RESTART' in the management client. Restarting of individual nodes while in Single User Mode remains not permitted. (Bug #31056) * Formerly, when using MySQL Cluster Replication, records for `empty' epochs--that is, epochs in which no changes to *Note `NDBCLUSTER': mysql-cluster. data or tables took place--were inserted into the `ndb_apply_status' and `ndb_binlog_index' tables on the slave even when `--log-slave-updates' was disabled. Beginning with MySQL Cluster NDB 6.2.16 and MySQL Cluster NDB 6.3.13 this was changed so that these `empty' eopchs were no longer logged. However, it is now possible to re-enable the older behavior (and cause `empty' epochs to be logged) by using the `--ndb-log-empty-epochs' option. For more information, see *Note replication-options-slave::. See also Bug #37472. *Bugs fixed:* * A maximum of 11 `TUP' scans were permitted in parallel. (Bug #42084) * Trying to execute an *Note `ALTER ONLINE TABLE ... ADD COLUMN': alter-table. statement while inserting rows into the table caused *Note `mysqld': mysqld. to crash. (Bug #41905) * If the master node failed during a global checkpoint, it was possible in some circumstances for the new master to use an incorrect value for the global checkpoint index. This could occur only when the cluster used more than one node group. (Bug #41469) * API nodes disconnected too agressively from cluster when data nodes were being restarted. This could sometimes lead to the API node being unable to access the cluster at all during a rolling restart. (Bug #41462) * It was not possible to perform online upgrades from a MySQL Cluster NDB 6.2 release to MySQL Cluster NDB 6.3.8 or a later MySQL Cluster NDB 6.3 release. (Bug #41435) * Cluster log files were opened twice by internal log-handling code, resulting in a resource leak. (Bug #41362) * An abort path in the `DBLQH' kernel block failed to release a commit acknowledgment marker. This meant that, during node failure handling, the local query handler could be added multiple times to the marker record which could lead to additional node failures due an array overflow. (Bug #41296) * During node failure handling (of a data node other than the master), there was a chance that the master was waiting for a `GCP_NODEFINISHED' signal from the failed node after having received it from all other data nodes. If this occurred while the failed node had a transaction that was still being committed in the current epoch, the master node could crash in the `DBTC' kernel block when discovering that a transaction actually belonged to an epoch which was already completed. (Bug #41295) * Issuing `EXIT' in the management client sometimes caused the client to hang. (Bug #40922) * In the event that a MySQL Cluster backup failed due to file permissions issues, conflicting reports were issued in the management client. (Bug #34526) * If all data nodes were shut down, MySQL clients were unable to access *Note `NDBCLUSTER': mysql-cluster. tables and data even after the data nodes were restarted, unless the MySQL clients themselves were restarted. (Bug #33626) * *Disk Data*: Starting a cluster under load such that Disk Data tables used most of the undo buffer could cause data node failures. The fix for this bug also corrected an issue in the `LGMAN' kernel block where the amount of free space left in the undo buffer was miscalculated, causing buffer overruns. This could cause records in the buffer to be overwritten, leading to problems when restarting data nodes. (Bug #28077) * *Cluster Replication*: Sometimes, when using the `--ndb_log_orig' option, the `orig_epoch' and `orig_server_id' columns of the `ndb_binlog_index' table on the slave contained the ID and epoch of the local server instead. (Bug #41601) * *Cluster API*: `mgmapi.h' contained constructs which only worked in C++, but not in C. (Bug #27004)  File: manual.info, Node: mysql-cluster-news-5-1-30-ndb-6-3-20, Next: mysql-cluster-news-5-1-29-ndb-6-3-19, Prev: mysql-cluster-news-5-1-31-ndb-6-3-21, Up: mysql-cluster-news-6-3 17.7.4.31 Changes in MySQL Cluster NDB 6.3.20 (5.1.30-ndb-6.3.20) (17 December 2008) .................................................................................... This is a bugfix release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.3 release. Obtaining MySQL Cluster NDB 6.3 You can download MySQL Cluster NDB 6.3.20 source code and binaries for supported platforms from `http://dev.mysql.com/downloads/cluster/'. This release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.3 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.30 (see *Note news-5-1-30::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * *Cluster API*: Two new `Ndb_cluster_connection' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndb-cluster-connection.html#ndb-ndb-cluster-connection) methods have been added to help in diagnosing problems with NDB API client connections. The `get_latest_error()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndb-cluster-connection-methods.html#ndb-ndb-cluster-connection-get-latest-error) method tells whether or not the latest connection attempt succeeded; if the attempt failed, `get_latest_error_msg()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndb-cluster-connection-methods.html#ndb-ndb-cluster-connection-get-latest-error-msg) provides an error message giving the reason. *Bugs fixed:* * If a transaction was aborted during the handling of a data node failure, this could lead to the later handling of an API node failure not being completed. (Bug #41214) * Issuing `SHOW TABLES' repeatedly could cause *Note `NDBCLUSTER': mysql-cluster. tables to be dropped. (Bug #40854) * Statements of the form `UPDATE ... ORDER BY ... LIMIT' run against *Note `NDBCLUSTER': mysql-cluster. tables failed to update all matching rows, or failed with the error `Can't find record in 'TABLE_NAME''. (Bug #40081) * Start phase reporting was inconsistent between the management client and the cluster log. (Bug #39667) * Status messages shown in the management client when restarting a management node were inappropriate and misleading. Now, when restarting a management node, the messages displayed are as follows, where NODE_ID is the management node's node ID: ndb_mgm> NODE_ID RESTART Shutting down MGM node NODE_ID for restart Node NODE_ID is being restarted ndb_mgm> (Bug #29275) * *Partitioning*: A query on a user-partitioned table caused MySQL to crash, where the query had the following characteristics: * The query's `WHERE' clause referenced an indexed column that was also in the partitioning key. * The query's `WHERE' clause included a value found in the partition. * The query's `WHERE' clause used the `<' or `<>' operators to compare with the indexed column's value with a constant. * The query used an `ORDER BY' clause, and the same indexed column was used in the `ORDER BY' clause. * The `ORDER BY' clause used an explcit or implicit `ASC' sort priority. Two examples of such a query are given here, where `a' represents an indexed column used in the table's partitioning key: 1. SELECT * FROM TABLE WHERE a < CONSTANT ORDER BY a; 2. SELECT * FROM TABLE WHERE a <> CONSTANT ORDER BY a; This bug was introduced in MySQL Cluster NDB 6.3.19. (Bug #40954) This regression was introduced by Bug #30573, Bug #33257, Bug #33555. * *Replication*: Issuing the statement `CHANGE MASTER TO ... MASTER_HEARTBEAT_PERIOD = PERIOD' using a value for PERIOD outside the permitted range caused the slave to crash. (Bug #39077) * *Disk Data*: This improves on a previous fix for this issue that was made in MySQL Cluster 6.3.8. (Bug #37116) See also Bug #29186. * *Cluster API*: When creating a scan using an `NdbScanFilter' object, it was possible to specify conditions against a `BIT' column, but the correct rows were not returned when the scan was executed. As part of this fix, 4 new comparison operators have been implemented for use with scans on `BIT' columns: * `COL_AND_MASK_EQ_MASK' * `COL_AND_MASK_NE_MASK' * `COL_AND_MASK_EQ_ZERO' * `COL_AND_MASK_NE_ZERO' For more information about these operators, see The `NdbScanFilter::BinaryCondition' Type (http://dev.mysql.com/doc/ndbapi/en/ndb-ndbscanfilter-types.html#ndb-ndbscanfilter-binarycondition). Equivalent methods are now also defined for `NdbInterpretedCode'; for more information, see `NdbInterpretedCode' Bitwise Comparison Operations (http://dev.mysql.com/doc/ndbapi/en/ndb-ndbinterpretedcode-methods.html#ndb-ndbinterpretedcode-bitwise-comparisons). (Bug #40535)  File: manual.info, Node: mysql-cluster-news-5-1-29-ndb-6-3-19, Next: mysql-cluster-news-5-1-28-ndb-6-3-18, Prev: mysql-cluster-news-5-1-30-ndb-6-3-20, Up: mysql-cluster-news-6-3 17.7.4.32 Changes in MySQL Cluster NDB 6.3.19 (5.1.29-ndb-6.3.19) (21 November 2008) .................................................................................... This is a bugfix release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.3 release. This release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.3 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.29 (see *Note news-5-1-29::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * *Cluster API*: *Important Change*: MGM API applications exited without raising any errors if the connection to the management server was lost. The fix for this issue includes two changes: 1. The MGM API now provides its own `SIGPIPE' handler to catch the `broken pipe' error that occurs when writing to a closed or reset socket. This means that MGM API now behaves the same as NDB API in this regard. 2. A new function `ndb_mgm_set_ignore_sigpipe()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-set-ignore-sigpipe.html) has been added to the MGM API. This function makes it possible to bypass the `SIGPIPE' handler provded by the MGM API. (Bug #40498) * *Cluster Replication*: *Important Note*: This release of MySQL Cluster derives in part from MySQL 5.1.29, where the default value for the `--binlog-format' option changed to `STATEMENT'. That change does _not_ affect this or future MySQL Cluster NDB 6.x releases, where the default value for this option remains `MIXED', since MySQL Cluster Replication does not work with the statement-based format. (Bug #40586) * When performing an initial start of a data node, fragment log files were always created sparsely--that is, not all bytes were written. Now it is possible to override this behavior using the new `InitFragmentLogFiles' configuration parameter. (Bug #40847) *Bugs fixed:* * *Cluster API*: Failed operations on *Note `BLOB': blob. and *Note `TEXT': blob. columns were not always reported correctly to the originating SQL node. Such errors were sometimes reported as being due to timeouts, when the actual problem was a transporter overload due to insufficient buffer space. (Bug #39867, Bug #39879) * Undo logs and data files were created in 32K increments. Now these files are created in 512K increments, resulting in shorter creation times. (Bug #40815) * Redo log creation was very slow on some platforms, causing MySQL Cluster to start more slowly than necessary with some combinations of hardware and operating system. This was due to all write operations being synchronized to disk while creating a redo log file. Now this synchronization occurs only after the redo log has been created. (Bug #40734) * Transaction failures took longer to handle than was necessary. When a data node acting as transaction coordinator (TC) failed, the surviving data nodes did not inform the API node initiating the transaction of this until the failure had been processed by all protocols. However, the API node needed only to know about failure handling by the transaction protocol--that is, it needed to be informed only about the TC takeover process. Now, API nodes (including MySQL servers acting as cluster SQL nodes) are informed as soon as the TC takeover is complete, so that it can carry on operating more quickly. (Bug #40697) * It was theoretically possible for stale data to be read from *Note `NDBCLUSTER': mysql-cluster. tables when the transaction isolation level was set to `ReadCommitted'. (Bug #40543) * The `LockExecuteThreadToCPU' and `LockMaintThreadsToCPU' parameters did not work on Solaris. (Bug #40521) * `SET SESSION ndb_optimized_node_selection = 1' failed with an invalid warning message. (Bug #40457) * A restarting data node could fail with an error in the `DBDIH' kernel block when a local or global checkpoint was started or triggered just as the node made a request for data from another data node. (Bug #40370) * Restoring a MySQL Cluster from a dump made using *Note `mysqldump': mysqldump. failed due to a spurious error: `Can't execute the given command because you have active locked tables or an active transaction'. (Bug #40346) * `O_DIRECT' was incorrectly disabled when making MySQL Cluster backups. (Bug #40205) * Heavy DDL usage caused the *Note `mysqld': mysqld. processes to hang due to a timeout error (*Note `NDB': mysql-cluster. error code 266). (Bug #39885) * Executing *Note `EXPLAIN SELECT': explain. on an *Note `NDBCLUSTER': mysql-cluster. table could cause *Note `mysqld': mysqld. to crash. (Bug #39872) * Events logged after setting `ALL CLUSTERLOG STATISTICS=15' in the management client did not always include the node ID of the reporting node. (Bug #39839) * The MySQL Query Cache did not function correctly with *Note `NDBCLUSTER': mysql-cluster. tables containing *Note `TEXT': blob. columns. (Bug #39295) * A segfault in `Logger::Log' caused *Note `ndbd': mysql-cluster-programs-ndbd. to hang indefinitely. This fix improves on an earlier one for this issue, first made in MySQL Cluster NDB 6.2.16 and MySQL Cluster NDB 6.3.17. (Bug #39180) See also Bug #38609. * Memory leaks could occur in handling of strings used for storing cluster metadata and providing output to users. (Bug #38662) * A duplicate key or other error raised when inserting into an *Note `NDBCLUSTER': mysql-cluster. table caused the current transaction to abort, after which any SQL statement other than a *Note `ROLLBACK': commit. failed. With this fix, the *Note `NDBCLUSTER': mysql-cluster. storage engine now performs an implicit rollback when a transaction is aborted in this way; it is no longer necessary to issue an explicit *Note `ROLLBACK': commit. statement, and the next statement that is issued automatically begins a new transaction. *Note*: It remains necessary in such cases to retry the complete transaction, regardless of which statement caused it to be aborted. (Bug #32656) See also Bug #47654. * Error messages for *Note `NDBCLUSTER': mysql-cluster. error codes 1224 and 1227 were missing. (Bug #28496) * *Partitioning*: Dropping or creating an index on a partitioned table managed by the `InnoDB' Plugin locked the table. (Bug #37453) * *Disk Data*: Issuing concurrent *Note `CREATE TABLESPACE': create-tablespace, *Note `ALTER TABLESPACE': alter-tablespace, *Note `CREATE LOGFILE GROUP': create-logfile-group, or *Note `ALTER LOGFILE GROUP': alter-logfile-group. statements on separate SQL nodes caused a resource leak that led to data node crashes when these statements were used again later. (Bug #40921) * *Disk Data*: Disk-based variable-length columns were not always handled like their memory-based equivalents, which could potentially lead to a crash of cluster data nodes. (Bug #39645) * *Disk Data*: `O_SYNC' was incorrectly disabled on platforms that do not support `O_DIRECT'. This issue was noted on Solaris but could have affected other platforms not having `O_DIRECT' capability. (Bug #34638) * *Cluster API*: The MGM API reset error codes on management server handles before checking them. This meant that calling an MGM API function with a null handle caused applications to crash. (Bug #40455) * *Cluster API*: It was not always possible to access parent objects directly from `NdbBlob', `NdbOperation', and `NdbScanOperation' objects. To alleviate this problem, a new `getNdbOperation()' method has been added to `NdbBlob' and new getNdbTransaction() methods have been added to `NdbOperation' and `NdbScanOperation'. In addition, a const variant of `NdbOperation::getErrorLine()' is now also available. (Bug #40242) * *Cluster API*: `NdbScanOperation::getBlobHandle()' failed when used with incorrect column names or numbers. (Bug #40241) * *Cluster API*: The MGM API function `ndb_mgm_listen_event()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-listen-event.html) ignored bind addresses. As part of this fix, it is now possible to specify bind addresses in connectstrings. See *Note mysql-cluster-connectstring::, for more information. (Bug #38473) * *Cluster API*: The NDB API example programs included in MySQL Cluster source distributions failed to compile. (Bug #37491) See also Bug #40238.  File: manual.info, Node: mysql-cluster-news-5-1-28-ndb-6-3-18, Next: mysql-cluster-news-5-1-27-ndb-6-3-17, Prev: mysql-cluster-news-5-1-29-ndb-6-3-19, Up: mysql-cluster-news-6-3 17.7.4.33 Changes in MySQL Cluster NDB 6.3.18 (5.1.28-ndb-6.3.18) (03 October 2008) ................................................................................... This is a bugfix release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.3 release. Obtaining MySQL Cluster NDB 6.3 You can download the latest MySQL Cluster NDB 6.3 source code and binaries for supported platforms from `http://dev.mysql.com/downloads/cluster/'. This release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.3 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.28 (see *Note news-5-1-28::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * It is no longer a requirement for database autodiscovery that an SQL node already be connected to the cluster at the time that a database is created on another SQL node. It is no longer necessary to issue *Note `CREATE DATABASE': create-database. (or *Note `CREATE SCHEMA': create-database.) statements on an SQL node joining the cluster after a database is created for the new SQL node to see the database and any `NDCLUSTER' tables that it contains. (Bug #39612) *Bugs fixed:* * When a transaction included a multi-row insert to an *Note `NDBCLUSTER': mysql-cluster. table that caused a constraint violation, the transaction failed to roll back. (Bug #395638) * Starting the MySQL Server with the `--ndbcluster' option plus an invalid command-line option (for example, using *Note `mysqld': mysqld. `--ndbcluster --foobar') caused it to hang while shutting down the binlog thread. (Bug #39635) * Dropping and then re-creating a database on one SQL node caused other SQL nodes to hang. (Bug #39613) * Setting a low value of `MaxNoOfLocalScans' (< 100) and performing a large number of (certain) scans could cause the Transaction Coordinator to run out of scan fragment records, and then crash. Now when this resource is exhausted, the cluster returns Error 291 (`Out of scanfrag records in TC (increase MaxNoOfLocalScans)') instead. (Bug #39549) * Creating a unique index on an *Note `NDBCLUSTER': mysql-cluster. table caused a memory leak in the *Note `NDB': mysql-cluster. subscription manager (`SUMA') which could lead to mysqld hanging, due to the fact that the resource shortage was not reported back to the *Note `NDB': mysql-cluster. kernel correctly. (Bug #39518) See also Bug #39450. * Embedded *Note `libmysqld': libmysqld. with *Note `NDB': mysql-cluster. did not drop table events. (Bug #39450) * Unique identifiers in tables having no primary key were not cached. This fix has been observed to increase the efficiency of *Note `INSERT': insert. operations on such tables by as much as 50%. (Bug #39267) * When restarting a data node, an excessively long shutodwn message could cause the node process to crash. (Bug #38580) * After a forced shutdown and initial restart of the cluster, it was possible for SQL nodes to retain `.frm' files corresponding to *Note `NDBCLUSTER': mysql-cluster. tables that had been dropped, and thus to be unaware that these tables no longer existed. In such cases, attempting to re-create the tables using `CREATE TABLE IF NOT EXISTS' could fail with a spurious `Table ... doesn't exist' error. (Bug #37921) * A statement of the form `DELETE FROM TABLE WHERE PRIMARY_KEY=VALUE' or `UPDATE TABLE WHERE PRIMARY_KEY=VALUE' where there was no row whose primary key column had the stated VALUE appeared to succeed, with the server reporting that 1 row had been changed. This issue was only known to affect MySQL Cluster NDB 6.3.11 and later NDB 6.3 versions. (Bug #37153) * *Cluster Replication*: In some cases, dropping a database on the master could cause table logging to fail on the slave, or, when using a debug build, could cause the slave *Note `mysqld': mysqld. to fail completely. (Bug #39404) * *Cluster API*: Passing a value greater than 65535 to `NdbInterpretedCode::add_val()' and `NdbInterpretedCode::sub_val()' caused these methods to have no effect. (Bug #39536)  File: manual.info, Node: mysql-cluster-news-5-1-27-ndb-6-3-17, Next: mysql-cluster-news-5-1-24-ndb-6-3-16, Prev: mysql-cluster-news-5-1-28-ndb-6-3-18, Up: mysql-cluster-news-6-3 17.7.4.34 Changes in MySQL Cluster NDB 6.3.17 (5.1.27-ndb-6.3.17) (28 August 2008) .................................................................................. This is a new release, fixing recently discovered bugs in previous MySQL Cluster NDB 6.3 releases. Obtaining MySQL Cluster NDB 6.3 Previously, MySQL Cluster NDB 6.3 releases were source-only releases which required compiling and installing using the instructions found in *Note source-installation::, and in *Note mysql-cluster-installation::. Beginning with MySQL Cluster NDB 6.3.17, binaries built from NDB 6.3 sources are also available. You can download the latest MySQL Cluster NDB 6.2 source code and binaries for supported platforms from http://dev.mysql.com/downloads/cluster/. This release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.3 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.27 (see *Note news-5-1-27::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Bugs fixed:* * *Packaging*: Support for the `InnoDB' storage engine was missing from the GPL source releases. An updated GPL source tarball `mysql-5.1.27-ndb-6.3.17-innodb.tar.gz' which includes code for building `InnoDB' can be found on the MySQL FTP site (ftp://ftp.mysql.com/pub/mysql/download/cluster_telco/mysql-5.1.27-ndb-6.3.17/). * `MgmtSrvr::allocNodeId()' left a mutex locked following an `Ambiguity for node if %d' error. (Bug #39158) * An invalid path specification caused `mysql-test-run.pl' to fail. (Bug #39026) * During transactional coordinator takeover (directly after node failure), the LQH finding an operation in the `LOG_COMMIT' state sent an `LQH_TRANS_CONF' signal twice, causing the TC to fail. (Bug #38930) * An invalid memory access caused the management server to crash on Solaris Sparc platforms. (Bug #38628) * A segfault in `Logger::Log' caused *Note `ndbd': mysql-cluster-programs-ndbd. to hang indefinitely. (Bug #38609) * *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. failed to start on older Linux distributions (2.4 kernels) that did not support e-polling. (Bug #38592) * *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. sometimes performed unnecessary network I/O with the client. This in combination with other factors led to long-running threads that were attempting to write to clients that no longer existed. (Bug #38563) * *Note `ndb_restore': mysql-cluster-programs-ndb-restore. failed with a floating point exception due to a division by zero error when trying to restore certain data files. (Bug #38520) * A failed connection to the management server could cause a resource leak in *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. (Bug #38424) * Failure to parse configuration parameters could cause a memory leak in the NDB log parser. (Bug #38380) * Renaming an *Note `NDBCLUSTER': mysql-cluster. table on one SQL node, caused a trigger on this table to be deleted on another SQL node. (Bug #36658) * Attempting to add a `UNIQUE INDEX' twice to an *Note `NDBCLUSTER': mysql-cluster. table, then deleting rows from the table could cause the MySQL Server to crash. (Bug #35599) * *Note `ndb_restore': mysql-cluster-programs-ndb-restore. failed when a single table was specified. (Bug #33801) * `GCP_COMMIT' did not wait for transaction takeover during node failure. This could cause `GCP_SAVE_REQ' to be executed too early. This could also cause (very rarely) replication to skip rows. (Bug #30780) * *Cluster Replication*: During a parallel node restart, the starting nodes could (sometimes) incorrectly synchronize subscriptions among themselves. Instead, this synchronization now takes place only among nodes that have actually (completely) started. (Bug #38767) * *Cluster API*: Support for Multi-Range Read index scans using the old API (using, for example, `NdbIndexScanOperation::setBound()' or `NdbIndexScanOperation::end_of_bound()') were dropped in MySQL Cluster NDB 6.2. This functionality is restored in MySQL Cluster NDB 6.3 beginning with 6.3.17, but remains unavailable in MySQL Cluster NDB 6.2. Both MySQL Cluster NDB 6.2 and 6.3 support Multi-Range Read scans through the `NdbRecord' API. (Bug #38791) * *Cluster API*: The `NdbScanOperation::readTuples()' method could be called multiple times without error. (Bug #38717) * *Cluster API*: Certain Multi-Range Read scans involving `IS NULL' and `IS NOT NULL' comparisons failed with an error in the *Note `NDB': mysql-cluster. local query handler. (Bug #38204) * *Cluster API*: Problems with the public headers prevented *Note `NDB': mysql-cluster. applications from being built with warnings turned on. (Bug #38177) * *Cluster API*: Creating an `NdbScanFilter' object using an `NdbScanOperation' object that had not yet had its `readTuples()' method called resulted in a crash when later attempting to use the `NdbScanFilter'. (Bug #37986) * *Cluster API*: Executing an `NdbRecord' interpreted delete created with an `ANYVALUE' option caused the transaction to abort. (Bug #37672)  File: manual.info, Node: mysql-cluster-news-5-1-24-ndb-6-3-16, Next: mysql-cluster-news-5-1-24-ndb-6-3-15, Prev: mysql-cluster-news-5-1-27-ndb-6-3-17, Up: mysql-cluster-news-6-3 17.7.4.35 Changes in MySQL Cluster NDB 6.3.16 (5.1.24-ndb-6.3.16) (27 June 2008) ................................................................................ This is a new source release, fixing recently discovered bugs in previous MySQL Cluster NDB 6.3 releases. Obtaining MySQL Cluster NDB 6.3 This is a source-only release, which you must compile and install using the instructions found in *Note source-installation::, and in *Note mysql-cluster-installation::. You can download the GPL source tarball from the MySQL FTP site at `ftp://ftp.mysql.com/pub/mysql/download/cluster_telco/'. This release incorporates all bugfixes and changes made in the previous MySQL Cluster NDB 6.3 release, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.24 (see *Note news-5-1-24::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * Event buffer lag reports are now written to the cluster log. (Bug #37427) * Added the `--no-binlog' option for *Note `ndb_restore': mysql-cluster-programs-ndb-restore. When used, this option prevents information being written to SQL node binary logs from the restoration of a cluster backup. (Bug #30452) *Bugs fixed:* * *Cluster API*: Changing the system time on data nodes could cause MGM API applications to hang and the data nodes to crash. (Bug #35607) * Failure of a data node could sometimes cause mysqld to crash. (Bug #37628) * `DELETE ... WHERE UNIQUE_INDEX_COLUMN=VALUE' deleted the wrong row from the table. (Bug #37516) * If subscription was terminated while a node was down, the epoch was not properly acknowledged by that node. (Bug #37442) * `libmysqld' failed to wait for the cluster binlog thread to terminate before exiting. (Bug #37429) * In rare circumstances, a connection followed by a disconnection could give rise to a `stale' connection where the connection still existed but was not seen by the transporter. (Bug #37338) * Queries against *Note `NDBCLUSTER': mysql-cluster. tables were cached only if `autocommit' was in use. (Bug #36692) * *Cluster Replication*: Data was written to the binlog with `--log-slave-updates' disabled. (Bug #37472) * *Cluster API*: When some operations succeeded and some failed following a call to `NdbTransaction::execute(Commit, AO_IgnoreOnError)', a race condition could cause spurious occurrences of NDB API Error 4011 (`Internal error'). (Bug #37158) * *Cluster API*: Creating a table on an SQL node, then starting an NDB API application that listened for events from this table, then dropping the table from an SQL node, prevented data node restarts. (Bug #32949, Bug #37279) * *Cluster API*: A buffer overrun in `NdbBlob::setValue()' caused erroneous results on Mac OS X. (Bug #31284)  File: manual.info, Node: mysql-cluster-news-5-1-24-ndb-6-3-15, Next: mysql-cluster-news-5-1-24-ndb-6-3-14, Prev: mysql-cluster-news-5-1-24-ndb-6-3-16, Up: mysql-cluster-news-6-3 17.7.4.36 Changes in MySQL Cluster NDB 6.3.15 (5.1.24-ndb-6.3.15) (30 May 2008) ............................................................................... This is a new source release, fixing recently discovered bugs in previous MySQL Cluster NDB 6.3 releases. Obtaining MySQL Cluster NDB 6.3 This is a source-only release, which you must compile and install using the instructions found in *Note source-installation::, and in *Note mysql-cluster-installation::. You can download the GPL source tarball from the MySQL FTP site at `ftp://ftp.mysql.com/pub/mysql/download/cluster_telco/'. This release incorporates all bugfixes and changes made in the previous MySQL Cluster NDB 6.3 release, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.24 (see *Note news-5-1-24::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Bugs fixed:* * In certain rare situations, `ndb_size.pl' could fail with the error `Can't use string ("VALUE") as a HASH ref while "strict refs" in use'. (Bug #43022) * Under some circumstances, a failed *Note `CREATE TABLE': create-table. could mean that subsequent *Note `CREATE TABLE': create-table. statements caused node failures. (Bug #37092) * A fail attempt to create an *Note `NDB': mysql-cluster. table could in some cases lead to resource leaks or cluster failures. (Bug #37072) * Attempting to create a native backup of *Note `NDB': mysql-cluster. tables having a large number of `NULL' columns and data could lead to node failures. (Bug #37039) * Checking of API node connections was not efficiently handled. (Bug #36843) * Attempting to delete a nonexistent row from a table containing a *Note `TEXT': blob. or *Note `BLOB': blob. column within a transaction caused the transaction to fail. (Bug #36756) See also Bug #36851. * If the combined total of tables and indexes in the cluster was greater than 4096, issuing `START BACKUP' caused data nodes to fail. (Bug #36044) * Where column values to be compared in a query were of the *Note `VARCHAR': char. or *Note `VARBINARY': binary-varbinary. types, *Note `NDBCLUSTER': mysql-cluster. passed a value padded to the full size of the column, which caused unnecessary data to be sent to the data nodes. This also had the effect of wasting CPU and network bandwidth, and causing condition pushdown to be disabled where it could (and should) otherwise have been applied. (Bug #35393) * When dropping a table failed for any reason (such as when in single user mode) then the corresponding `.ndb' file was still removed. * *Replication*: When flushing tables, there was a slight chance that the flush occurred between the processing of one table map event and the next. Since the tables were opened one by one, subsequent locking of tables would cause the slave to crash. This problem was observed when replicating *Note `NDBCLUSTER': mysql-cluster. or `InnoDB' tables, when executing multi-table updates, and when a trigger or a stored routine performed an (additional) insert on a table so that two tables were effectively being inserted into in the same statement. (Bug #36197) * *Cluster API*: Ordered index scans were not pruned correctly where a partitioning key was specified with an EQ-bound. (Bug #36950) * *Cluster API*: When an insert operation involving *Note `BLOB': blob. data was attempted on a row which already existed, no duplicate key error was correctly reported and the transaction is incorrectly aborted. In some cases, the existing row could also become corrupted. (Bug #36851) See also Bug #26756. * *Cluster API*: `NdbApi.hpp' depended on `ndb_global.h', which was not actually installed, causing the compilation of programs that used `NdbApi.hpp' to fail. (Bug #35853)  File: manual.info, Node: mysql-cluster-news-5-1-24-ndb-6-3-14, Next: mysql-cluster-news-5-1-24-ndb-6-3-13, Prev: mysql-cluster-news-5-1-24-ndb-6-3-15, Up: mysql-cluster-news-6-3 17.7.4.37 Changes in MySQL Cluster NDB 6.3.14 (5.1.24-ndb-6.3.14) (11 May 2008) ............................................................................... This is a new source release, fixing recently discovered bugs in previous MySQL Cluster NDB 6.3 releases. Obtaining MySQL Cluster NDB 6.3 This is a source-only release, which you must compile and install using the instructions found in *Note source-installation::, and in *Note mysql-cluster-installation::. You can download the GPL source tarball from the MySQL FTP site at `ftp://ftp.mysql.com/pub/mysql/download/cluster_telco/'. This release incorporates all bugfixes and changes made in the previous MySQL Cluster NDB 6.3 release, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.24 (see *Note news-5-1-24::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Bugs fixed:* * `SET GLOBAL ndb_extra_logging' caused *Note `mysqld': mysqld. to crash. (Bug #36547) * A race condition caused by a failure in epoll handling could cause data nodes to fail. (Bug #36537) * Under certain rare circumstances, the failure of the new master node while attempting a node takeover would cause takeover errors to repeat without being resolved. (Bug #36199, Bug #36246, Bug #36247, Bug #36276) * When more than one SQL node connected to the cluster at the same time, creation of the `mysql.ndb_schema' table failed on one of them with an explicit `Table exists' error, which was not necessary. (Bug #35943) * *Note `mysqld': mysqld. failed to start after running *Note `mysql_upgrade': mysql-upgrade. (Bug #35708) * Notification of a cascading master node failures could sometimes not be transmitted correctly (that is, transmission of the `NF_COMPLETEREP' signal could fail), leading to transactions hanging and timing out (*Note `NDB': mysql-cluster. error 4012), scans hanging, and failure of the management server process. (Bug #32645) * If an API node disconnected and then reconnected during Start Phase 8, then the connection could be `blocked'--that is, the `QMGR' kernel block failed to detect that the API node was in fact connected to the cluster, causing issues with the *Note `NDB': mysql-cluster. Subscription Manager (`SUMA'). * *Note `NDB': mysql-cluster. error 1427 (`Api node died, when SUB_START_REQ reached node') was incorrectly classified as a schema error rather than a temporary error. * *Cluster Replication*: Performing `SELECT ... FROM mysql.ndb_apply_status' before the *Note `mysqld': mysqld. process had connected to the cluster failed, and caused this table never to be created. (Bug #36123) * *Cluster API*: Accesing the debug version of `libndbclient' using `dlopen()' resulted in a segmentation fault. (Bug #35927) * *Cluster API*: Attempting to pass a nonexistent column name to the `equal()' and `setValue()' methods of `NdbOperation' caused NDB API applications to crash. Now the column name is checked, and an error is returned in the event that the column is not found. (Bug #33747) * *Cluster API*: Relocation errors were encountered when trying to compile NDB API applications on a number of platforms, including 64-bit Linux. As a result, `libmysys', `libmystrings', and `libdbug' have been changed from normal libraries to `noinst' `libtool' helper libraries. They are no longer installed as separate libraries; instead, all necessary symbols from these are added directly to `libndbclient'. This means that NDB API programs now need to be linked using only `-lndbclient'. (Bug #29791, Bug #11746931)  File: manual.info, Node: mysql-cluster-news-5-1-24-ndb-6-3-13, Next: mysql-cluster-news-5-1-23-ndb-6-3-12, Prev: mysql-cluster-news-5-1-24-ndb-6-3-14, Up: mysql-cluster-news-6-3 17.7.4.38 Changes in MySQL Cluster NDB 6.3.13 (5.1.24-ndb-6.3.13) (10 April 2008) ................................................................................. This is a new source release, fixing recently discovered bugs in previous MySQL Cluster NDB 6.3 releases. Obtaining MySQL Cluster NDB 6.3 This is a source-only release, which you must compile and install using the instructions found in *Note source-installation::, and in *Note mysql-cluster-installation::. You can download the GPL source tarball from the MySQL FTP site at `ftp://ftp.mysql.com/pub/mysql/download/cluster_telco/'. This release incorporates all bugfixes and changes made in the previous MySQL Cluster NDB 6.3 release, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.24 (see *Note news-5-1-24::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * The *Note `ndbd': mysql-cluster-programs-ndbd. and *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. man pages have been reclassified from volume 1 to volume 8. (Bug #34642) *Bugs fixed:* * *Important Change*: *Note `mysqld_safe': mysqld-safe. now traps Signal 13 (`SIGPIPE') so that this signal no longer kills the MySQL server process. (Bug #33984) * Node or system restarts could fail due an unitialized variable in the `DTUP' kernel block. This issue was found in MySQL Cluster NDB 6.3.11. (Bug #35797) * If an error occurred while executing a statement involving a *Note `BLOB': blob. or *Note `TEXT': blob. column of an *Note `NDB': mysql-cluster. table, a memory leak could result. (Bug #35593) * It was not possible to determine the value used for the `--ndb-cluster-connection-pool' option in the *Note `mysql': mysql. client. Now this value is reported as a system status variable. (Bug #35573) * The *Note `ndb_waiter': mysql-cluster-programs-ndb-waiter. utility wrongly calculated timeouts. (Bug #35435) * A *Note `SELECT': select. on a table with a nonindexed, large *Note `VARCHAR': char. column which resulted in condition pushdown on this column could cause *Note `mysqld': mysqld. to crash. (Bug #35413) * *Note `ndb_restore': mysql-cluster-programs-ndb-restore. incorrectly handled some data types when applying log files from backups. (Bug #35343) * In some circumstances, a stopped data node was handled incorrectly, leading to redo log space being exhausted following an initial restart of the node, or an initial or partial restart of the cluster (the wrong CGI might be used in such cases). This could happen, for example, when a node was stopped following the creation of a new table, but before a new LCP could be executed. (Bug #35241) * `SELECT ... LIKE ...' queries yielded incorrect results when used on *Note `NDB': mysql-cluster. tables. As part of this fix, condition pushdown of such queries has been disabled; re-enabling it is expected to be done as part of a later, permanent fix for this issue. (Bug #35185) * *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. reported errors to `STDOUT' rather than to `STDERR'. (Bug #35169) * Nested Multi-Range Read scans failed when the second Multi-Range Read released the first read's unprocessed operations, sometimes leading to an SQL node crash. (Bug #35137) * In some situations, a problem with synchronizing checkpoints between nodes could cause a system restart or a node restart to fail with `Error 630 during restore of TX'. (Bug #34756) * A node failure during an initial node restart followed by another node start could cause the master data node to fail, because it incorrectly gave the node permission to start even if the invalidated node's LCP was still running. (Bug #34702) * When a secondary index on a *Note `DECIMAL': numeric-types. column was used to retrieve data from an *Note `NDB': mysql-cluster. table, no results were returned even if the target table had a matched value in the column that was defined with the secondary index. (Bug #34515) * An *Note `UPDATE': update. on an *Note `NDB': mysql-cluster. table that set a new value for a unique key column could cause subsequent queries to fail. (Bug #34208) * If a data node in one node group was placed in the `not started' state (using `NODE_ID RESTART -n'), it was not possible to stop a data node in a different node group. (Bug #34201) * Numerous *Note `NDBCLUSTER': mysql-cluster. test failures occurred in builds compiled using `icc' on IA64 platforms. (Bug #31239) * If a `START BACKUP' command was issued while *Note `ndb_restore': mysql-cluster-programs-ndb-restore. was running, the backup being restored could be overwritten. (Bug #26498) * *Note `REPLACE': replace. statements did not work correctly with *Note `NDBCLUSTER': mysql-cluster. tables when all columns were not explicitly listed. (Bug #22045) * *Note `CREATE TABLE': create-table. and *Note `ALTER TABLE': alter-table. statements using `ENGINE=NDB' or `ENGINE=NDBCLUSTER' caused *Note `mysqld': mysqld. to fail on Solaris 10 for x86 platforms. (Bug #19911) * *Replication*: A *Note `CHANGE MASTER TO': change-master-to. statement with no `MASTER_HEARTBEAT_PERIOD' option failed to reset the heartbeat period to its default value. (Bug #34686) * *Cluster Replication*: In some cases, when updating only one or some columns in a table, the complete row was written to the binary log instead of only the updated column or columns, even when `ndb_log_updated_only' was set to 1. (Bug #35208) * *Cluster Replication*: Using `--ndb-wait-connected' caused the server to wait for a partial connection, plus an additional 3 seconds for a complete connection to the cluster. This could lead to issues with setting up the binary log. (Bug #34757) * *Cluster API*: Closing a scan before it was executed caused the application to segfault. (Bug #36375) * *Cluster API*: Using NDB API applications from older MySQL Cluster versions with `libndbclient' from newer ones caused the cluster to fail. (Bug #36124) * *Cluster API*: Some ordered index scans could return tuples out of order. (Bug #35908) * *Cluster API*: Scans having no bounds set were handled incorrectly. (Bug #35876) * *Cluster API*: `NdbScanFilter::getNdbOperation()', which was inadvertently removed in MySQL Cluster NDB 6.3.11, has been restored. (Bug #35854) * Enabling the `read_only' system variable while `autocommit' mode was enabled caused *Note `SELECT': select. statements for transactional storage engines to fail. (Bug #35732) * Executing a *Note `FLUSH PRIVILEGES': flush. statement after creating a temporary table in the `mysql' database with the same name as one of the MySQL system tables caused the server to crash. *Note*: While it is possible to shadow a system table in this way, the temporary table exists only for the current user and connection, and does not effect any user privileges. (Bug #33275)  File: manual.info, Node: mysql-cluster-news-5-1-23-ndb-6-3-12, Next: mysql-cluster-news-5-1-23-ndb-6-3-11, Prev: mysql-cluster-news-5-1-24-ndb-6-3-13, Up: mysql-cluster-news-6-3 17.7.4.39 Changes in MySQL Cluster NDB 6.3.12 (5.1.23-ndb-6.3.12) (05 April 2008) ................................................................................. MySQL Cluster NDB 6.3.12 was pulled due to issues discovered shortly after its release, and is no longer available. Users of MySQL Cluster NDB 6.3.10 and earlier MySQL Cluster NDB 6.3 releases should upgrade to MySQL Cluster NDB 6.3.13 or later. For information about bugfixes and feature enhancements that were originally scheduled to appear for the first time in this release, see *Note mysql-cluster-news-5-1-24-ndb-6-3-13::.  File: manual.info, Node: mysql-cluster-news-5-1-23-ndb-6-3-11, Next: mysql-cluster-news-5-1-23-ndb-6-3-10, Prev: mysql-cluster-news-5-1-23-ndb-6-3-12, Up: mysql-cluster-news-6-3 17.7.4.40 Changes in MySQL Cluster NDB 6.3.11 (5.1.23-ndb-6.3.11) (28 March 2008) ................................................................................. This release was pulled due to issues discovered shortly after its release, and is no longer available. Users of MySQL Cluster NDB 6.3.10 and earlier MySQL Cluster NDB 6.3 releases should upgrade to MySQL Cluster NDB 6.3.13 or later. For information about bugfixes and feature enhancements that were originally scheduled to appear for the first time in this release, see *Note mysql-cluster-news-5-1-24-ndb-6-3-13::.  File: manual.info, Node: mysql-cluster-news-5-1-23-ndb-6-3-10, Next: mysql-cluster-news-5-1-23-ndb-6-3-9, Prev: mysql-cluster-news-5-1-23-ndb-6-3-11, Up: mysql-cluster-news-6-3 17.7.4.41 Changes in MySQL Cluster NDB 6.3.10 (5.1.23-ndb-6.3.10) (17 February 2008) .................................................................................... This is a new Beta development release, fixing recently discovered bugs in previous MySQL Cluster NDB 6.3 releases. Obtaining MySQL Cluster NDB 6.3 This is a source-only release, which you must compile and install using the instructions found in *Note source-installation::, and in *Note mysql-cluster-installation::. You can download the GPL source tarball from the MySQL FTP site at `ftp://ftp.mysql.com/pub/mysql/download/cluster_telco/'. This Beta release incorporates all bugfixes and changes made in the previous MySQL Cluster NDB 6.3 release, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.23 (see *Note news-5-1-23::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Bugs fixed:* * Due to the reduction of the number of local checkpoints from 3 to 2 in MySQL Cluster NDB 6.3.8, a data node using ndbd from MySQL Cluster NDB 6.3.8 or later started using a file system from an earlier version could incorrectly invalidate local checkpoints too early during the startup process, causing the node to fail. (Bug #34596)  File: manual.info, Node: mysql-cluster-news-5-1-23-ndb-6-3-9, Next: mysql-cluster-news-5-1-23-ndb-6-3-8, Prev: mysql-cluster-news-5-1-23-ndb-6-3-10, Up: mysql-cluster-news-6-3 17.7.4.42 Changes in MySQL Cluster NDB 6.3.9 (5.1.23-ndb-6.3.9) (12 February 2008) .................................................................................. This is a new Beta development release, fixing recently discovered bugs in previous MySQL Cluster NDB 6.3 releases. Obtaining MySQL Cluster NDB 6.3 This is a source-only release, which you must compile and install using the instructions found in *Note source-installation::, and in *Note mysql-cluster-installation::. You can download the GPL source tarball from the MySQL FTP site at `ftp://ftp.mysql.com/pub/mysql/download/cluster_telco/'. This Beta release incorporates all bugfixes and changes made in the previous MySQL Cluster NDB 6.3 release, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.23 (see *Note news-5-1-23::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * Beginning with this version, MySQL Cluster NDB 6.3.X releases once again include the `InnoDB' storage engine. To enable `InnoDB', you must configure the build using `--with-innodb'. *Bugs fixed:* * Cluster failures could sometimes occur when performing more than three parallel takeovers during node restarts or system restarts. This affected MySQL Cluster NDB 6.3.X releases only. (Bug #34445) * Upgrades of a cluster using while a `DataMemory' setting in excess of 16 GB caused data nodes to fail. (Bug #34378) * Performing many SQL statements on *Note `NDB': mysql-cluster. tables while in `autocommit' mode caused a memory leak in *Note `mysqld': mysqld. (Bug #34275) * In certain rare circumstances, a race condition could occur between an aborted insert and a delete leading a data node crash. (Bug #34260) * Multi-table updates using ordered indexes during handling of node failures could cause other data nodes to fail. (Bug #34216) * When configured with *Note `NDB': mysql-cluster. support, MySQL failed to compile using `gcc' 4.3 on 64bit FreeBSD systems. (Bug #34169) * The failure of a DDL statement could sometimes lead to node failures when attempting to execute subsequent DDL statements. (Bug #34160) * Extremely long *Note `SELECT': select. statements (where the text of the statement was in excess of 50000 characters) against *Note `NDB': mysql-cluster. tables returned empty results. (Bug #34107) * When configured with *Note `NDB': mysql-cluster. support, MySQL failed to compile on 64bit FreeBSD systems. (Bug #34046) * Statements executing multiple inserts performed poorly on *Note `NDB': mysql-cluster. tables having `AUTO_INCREMENT' columns. (Bug #33534) * The *Note `ndb_waiter': mysql-cluster-programs-ndb-waiter. utility polled *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. excessively when obtaining the status of cluster data nodes. (Bug #32025) See also Bug #32023. * Transaction atomicity was sometimes not preserved between reads and inserts under high loads. (Bug #31477) * Having tables with a great many columns could cause Cluster backups to fail. (Bug #30172) * *Cluster Replication*: *Disk Data*: Statements violating unique keys on Disk Data tables (such as attempting to insert `NULL' into a `NOT NULL' column) could cause data nodes to fail. When the statement was executed from the binlog, this could also result in failure of the slave cluster. (Bug #34118) * *Disk Data*: Updating in-memory columns of one or more rows of Disk Data table, followed by deletion of these rows and re-insertion of them, caused data node failures. (Bug #33619) * *Cluster Replication*: Setting `--replicate-ignore-db=mysql' caused the `mysql.ndb_apply_status' table not to be replicated, breaking Cluster Replication. (Bug #28170)  File: manual.info, Node: mysql-cluster-news-5-1-23-ndb-6-3-8, Next: mysql-cluster-news-5-1-23-ndb-6-3-7, Prev: mysql-cluster-news-5-1-23-ndb-6-3-9, Up: mysql-cluster-news-6-3 17.7.4.43 Changes in MySQL Cluster NDB 6.3.8 (5.1.23-ndb-6.3.8) (29 January 2008 General Availability) ...................................................................................................... This is a new Beta development release, fixing recently discovered bugs in previous MySQL Cluster NDB 6.3 releases. Obtaining MySQL Cluster NDB 6.3 This is a source-only release, which you must compile and install using the instructions found in *Note source-installation::, and in *Note mysql-cluster-installation::. You can download the GPL source tarball from the MySQL FTP site at `ftp://ftp.mysql.com/pub/mysql/download/cluster_telco/'. This Beta release incorporates all bugfixes and changes made in the previous MySQL Cluster NDB 6.3 release, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.23 (see *Note news-5-1-23::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * *Cluster API*: *Important Change*: Because `NDB_LE_MemoryUsage.page_size_kb' shows memory page sizes in bytes rather than kilobytes, it has been renamed to `page_size_bytes'. The name `page_size_kb' is now deprecated and thus subject to removal in a future release, although it currently remains supported for reasons of backward compatibility. See The `Ndb_logevent_type' Type (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-logevent-type.html), for more information about `NDB_LE_MemoryUsage'. (Bug #30271) * *Note `ndb_restore': mysql-cluster-programs-ndb-restore. now supports basic _attribute promotion_; that is, data from a column of a given type can be restored to a column using a `larger' type. For example, Cluster backup data taken from a *Note `SMALLINT': numeric-types. column can be restored to a *Note `MEDIUMINT': numeric-types, *Note `INT': numeric-types, or *Note `BIGINT': numeric-types. column. For more information, see *Note mysql-cluster-programs-ndb-restore::. * Now only 2 local checkpoints are stored, rather than 3 as in previous MySQL Cluster versions. This lowers disk space requirements and reduces the size and number of redo log files needed. * The *Note `mysqld': mysqld. option `--ndb-batch-size' has been added. This enables control of the size of batches used for running transactions. * Node recovery can now be done in parallel, rather than sequentially, which can result in much faster recovery times. * Persistence of *Note `NDB': mysql-cluster. tables can now be controlled using the session variables `ndb_table_temporary' and `ndb_table_no_logging'. `ndb_table_no_logging' causes *Note `NDB': mysql-cluster. tables not to be checkpointed to disk. `ndb_table_temporary' has the same effect; in addition, when `ndb_table_temporary' is used, no *Note `NDB': mysql-cluster. table schema files are created. * *Note `OPTIMIZE TABLE': optimize-table. can now be interrupted. This can be done, for example, by killing the SQL thread performing the `OPTIMIZE' operation. *Bugs fixed:* * *Disk Data*: *Important Change*: It is no longer possible on 32-bit systems to issue statements appearing to create Disk Data log files or data files greater than 4 GB in size. (Trying to create log files or data files larger than 4 GB on 32-bit systems led to unrecoverable data node failures; such statements now fail with *Note `NDB': mysql-cluster. error 1515.) (Bug #29186) * *Replication*: The code implementing heartbeats did not check for possible errors in some circumstances; this kept the dump thread hanging while waiting for heartbeats loop even though the slave was no longer connected. (Bug #33332) * High numbers of insert operations, delete operations, or both could cause *Note `NDB': mysql-cluster. error 899 (`Rowid already allocated') to occur unnecessarily. (Bug #34033) * A periodic failure to flush the send buffer by the *Note `NDB': mysql-cluster. TCP transporter could cause a unnecessary delay of 10 ms between operations. (Bug #34005) * *Note `DROP TABLE': drop-table. did not free all data memory. This bug was observed in MySQL Cluster NDB 6.3.7 only. (Bug #33802) * A race condition could occur (very rarely) when the release of a GCI was followed by a data node failure. (Bug #33793) * Some tuple scans caused the wrong memory page to be accessed, leading to invalid results. This issue could affect both in-memory and Disk Data tables. (Bug #33739) * A failure to initialize an internal variable led to sporadic crashes during cluster testing. (Bug #33715) * The server failed to reject properly the creation of an *Note `NDB': mysql-cluster. table having an unindexed `AUTO_INCREMENT' column. (Bug #30417) * Issuing an *Note `INSERT ... ON DUPLICATE KEY UPDATE': insert-on-duplicate. concurrently with or following a *Note `TRUNCATE TABLE': truncate-table. statement on an *Note `NDB': mysql-cluster. table failed with *Note `NDB': mysql-cluster. error 4350 `Transaction already aborted'. (Bug #29851) * The Cluster backup process could not detect when there was no more disk space and instead continued to run until killed manually. Now the backup fails with an appropriate error when disk space is exhausted. (Bug #28647) * It was possible in `config.ini' to define cluster nodes having node IDs greater than the maximum permitted value. (Bug #28298) * Under some circumstances, a recovering data node did not use its own data, instead copying data from another node even when this was not required. This in effect bypassed the optimized node recovery protocol and caused recovery times to be unnecessarily long. (Bug #26913) * *Cluster Replication*: Consecutive DDL statements involving tables (*Note `CREATE TABLE': create-table, *Note `ALTER TABLE': alter-table, and *Note `DROP TABLE': drop-table.) could be executed so quickly that previous DDL statements upon which they depended were not yet written in the binary log. For example, if `DROP TABLE foo' was issued immediately following `CREATE TABLE foo', the `DROP' statement could fail because the `CREATE' had not yet been recorded. (Bug #34006) * *Cluster Replication*: *Note `ndb_restore -e': mysql-cluster-programs-ndb-restore. restored excessively large values to the `ndb_apply_status' table's `epoch' column when restoring to a MySQL Cluster version supporting Micro-GCPs from an older version that did not support these. A workaround when restoring to MySQL Cluster releases supporting micro-GCPs previous to MySQL Cluster NDB 6.3.8 is to perform a 32-bit shift on the `epoch' column values to reduce them to their proper size. (Bug #33406) * *Cluster API*: Transactions containing inserts or reads would hang during `NdbTransaction::execute()' calls made from NDB API applications built against a MySQL Cluster version that did not support micro-GCPs accessing a later version that supported micro-GCPs. This issue was observed while upgrading from MySQL Cluster NDB 6.1.23 to MySQL Cluster NDB 6.2.10 when the API application built against the earlier version attempted to access a data node already running the later version, even after disabling micro-GCPs by setting `TimeBetweenEpochs' equal to 0. (Bug #33895) * *Cluster API*: When reading a `BIT(64)' value using `NdbOperation:getValue()', 12 bytes were written to the buffer rather than the expected 8 bytes. (Bug #33750)  File: manual.info, Node: mysql-cluster-news-5-1-23-ndb-6-3-7, Next: mysql-cluster-news-5-1-22-ndb-6-3-6, Prev: mysql-cluster-news-5-1-23-ndb-6-3-8, Up: mysql-cluster-news-6-3 17.7.4.44 Changes in MySQL Cluster NDB 6.3.7 (5.1.23-ndb-6.3.7) (19 December 2007) .................................................................................. This is a new Beta development release, fixing recently discovered bugs in previous MySQL Cluster NDB 6.3 releases. Obtaining MySQL Cluster NDB 6.3 This is a source-only release, which you must compile and install using the instructions found in *Note source-installation::, and in *Note mysql-cluster-installation::. You can download the GPL source tarball from the MySQL FTP site at `ftp://ftp.mysql.com/pub/mysql/download/cluster_telco/'. This Beta release incorporates all bugfixes and changes made in the previous MySQL Cluster NDB 6.3 release, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.23 (see *Note news-5-1-23::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * Compressed local checkpoints and backups are now supported, resulting in a space savings of 50% or more over uncompressed LCPs and backups. Compression of these can be enabled in the `config.ini' file using the two new data node configuration parameters `CompressedLCP' and `CompressedBackup', respectively. * *Note `OPTIMIZE TABLE': optimize-table. is now supported for *Note `NDBCLUSTER': mysql-cluster. tables, subject to the following limitations: * Only in-memory tables are supported. `OPTIMIZE' still has no effect on Disk Data tables. * Only variable-length columns are supported. However, you can force columns defined using fixed-length data types to be dynamic using the `ROW_FORMAT' or `COLUMN_FORMAT' option with a *Note `CREATE TABLE': create-table. or *Note `ALTER TABLE': alter-table. statement. Memory reclaimed from an *Note `NDB': mysql-cluster. table using `OPTIMIZE' is generally available to the cluster, and not confined to the table from which it was recovered, unlike the case with memory freed using *Note `DELETE': delete. The performance of `OPTIMIZE' on *Note `NDB': mysql-cluster. tables can be regulated by adjusting the value of the `ndb_optimization_delay' system variable. * It is now possible to cause statements occurring within the same transaction to be run as a batch by setting the session variable `transaction_allow_batching' to `1' or `ON'. *Note*: To use this feature, `autocommit' must be disabled. *Bugs fixed:* * *Partitioning*: When partition pruning on an *Note `NDB': mysql-cluster. table resulted in an ordered index scan spanning only one partition, any descending flag for the scan was wrongly discarded, causing `ORDER BY DESC' to be treated as `ORDER BY ASC', `MAX()' to be handled incorrectly, and similar problems. (Bug #33061) * When all data and SQL nodes in the cluster were shut down abnormally (that is, other than by using `STOP' in the cluster management client), *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. used excessive amounts of CPU. (Bug #33237) * When using micro-GCPs, if a node failed while preparing for a global checkpoint, the master node would use the wrong GCI. (Bug #32922) * Under some conditions, performing an *Note `ALTER TABLE': alter-table. on an *Note `NDBCLUSTER': mysql-cluster. table failed with a `Table is full' error, even when only 25% of `DataMemory' was in use and the result should have been a table using less memory (for example, changing a `VARCHAR(100)' column to `VARCHAR(80)'). (Bug #32670) * *Cluster Replication*: *Replication*: Where a table being replicated had a *Note `TEXT': blob. or *Note `BLOB': blob. column, an *Note `UPDATE': update. on the master that did not refer explicitly to this column in the `WHERE' clause stopped the SQL thread on the slave with `Error in Write_rows event: row application failed. Got error 4288 'Blob handle for column not available' from NDBCLUSTER'. (Bug #30674) * *Cluster Replication*: Creating the `mysql.ndb_replication' table with the wrong number of columns for the primary key caused *Note `mysqld': mysqld. to crash. Now a `CREATE TABLE [mysql.]ndb_replication' statement that is invalid for this reason fails with the error `Bad schema for mysql.ndb_replication table. Message: Wrong number of primary keys, expected NUMBER'. (Bug #33159)  File: manual.info, Node: mysql-cluster-news-5-1-22-ndb-6-3-6, Next: mysql-cluster-news-5-1-22-ndb-6-3-5, Prev: mysql-cluster-news-5-1-23-ndb-6-3-7, Up: mysql-cluster-news-6-3 17.7.4.45 Changes in MySQL Cluster NDB 6.3.6 (5.1.22-ndb-6.3.6) (08 November 2007) .................................................................................. This is a new Beta development release, fixing recently discovered bugs in previous MySQL Cluster NDB 6.3 releases. Obtaining MySQL Cluster NDB 6.3 This is a source-only release, which you must compile and install using the instructions found in *Note source-installation::, and in *Note mysql-cluster-installation::. You can download the GPL source tarball from the MySQL FTP site at `ftp://ftp.mysql.com/pub/mysql/download/cluster_telco/'. This Beta release incorporates all bugfixes and changes made in the previous MySQL Cluster NDB 6.3 release, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.22 (see *Note news-5-1-22::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * *Important Note*: MySQL Cluster NDB 6.2 and 6.3 source archives are now available in separate commercial and GPL versions. Due to licensing concerns, previous MySQL Cluster NDB 6.2 and 6.3 source archives were removed from the FTP site. * The output of the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client `SHOW' and `STATUS' commands now indicates when the cluster is in single user mode. (Bug #27999) * Unnecessary reads when performing a primary key or unique key update have been reduced, and in some cases, eliminated. (It is almost never necessary to read a record prior to an update, the lone exception to this being when a primary key is updated, since this requires a delete followed by an insert, which must be prepared by reading the record.) Depending on the number of primary key and unique key lookups that are performed per transaction, this can yield a considerable improvement in performance. * Batched operations are now better supported for *Note `DELETE': delete. and *Note `UPDATE': update. (`UPDATE WHERE...' and muliple *Note `DELETE': delete.) * Introduced the `Ndb_execute_count' status variable, which measures the number of round trips made by queries to the *Note `NDB': mysql-cluster. kernel. *Bugs fixed:* * An insert or update with combined range and equality constraints failed when run against an *Note `NDB': mysql-cluster. table with the error `Got unknown error from NDB'. An example of such a statement would be `UPDATE t1 SET b = 5 WHERE a IN (7,8) OR a >= 10;'. (Bug #31874) * An error with an `if' statement in `sql/ha_ndbcluster.cc' could potentially lead to an infinite loop in case of failure when working with `AUTO_INCREMENT' columns in *Note `NDB': mysql-cluster. tables. (Bug #31810) * The *Note `NDB': mysql-cluster. storage engine code was not safe for strict-alias optimization in `gcc' 4.2.1. (Bug #31761) * *Note `ndb_restore': mysql-cluster-programs-ndb-restore. displayed incorrect backup file version information. This meant (for example) that, when attempting to restore a backup made from a MySQL 5.1.22 cluster to a MySQL Cluster NDB 6.3.3 cluster, the restore process failed with the error `Restore program older than backup version. Not supported. Use new restore program.' (Bug #31723) * Following an upgrade, *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. would fail with an ArbitrationError. (Bug #31690) * The *Note `NDB': mysql-cluster. management client command `NODE_ID REPORT MEMORY' provided no output when NODE_ID was the node ID of a management or API node. Now, when this occurs, the management client responds with `Node NODE_ID: is not a data node'. (Bug #29485) * Performing *Note `DELETE': delete. operations after a data node had been shut down could lead to inconsistent data following a restart of the node. (Bug #26450) * `UPDATE IGNORE' could sometimes fail on *Note `NDB': mysql-cluster. tables due to the use of unitialized data when checking for duplicate keys to be ignored. (Bug #25817) * *Cluster Replication*: *Replication*: A node failure during replication could lead to buckets out of order; now active subscribers are checked for, rather than empty buckets. (Bug #31701) * *Cluster Replication*: Updates performed unnecessary writes to the primary keys of the rows being updated. (Bug #31841) * *Cluster Replication*: Slave batching did not work correctly with *Note `UPDATE': update. statements. (Bug #31787) * *Cluster Replication*: When the master *Note `mysqld': mysqld. crashed or was restarted, no `LOST_EVENTS' entry was made in the binlog. (Bug #31484) See also Bug #21494.  File: manual.info, Node: mysql-cluster-news-5-1-22-ndb-6-3-5, Next: mysql-cluster-news-5-1-22-ndb-6-3-4, Prev: mysql-cluster-news-5-1-22-ndb-6-3-6, Up: mysql-cluster-news-6-3 17.7.4.46 Changes in MySQL Cluster NDB 6.3.5 (5.1.22-ndb-6.3.5) (17 October 2007) ................................................................................. This is a new Beta development release, fixing recently discovered bugs in previous MySQL Cluster NDB 6.3 releases. Obtaining MySQL Cluster NDB 6.3 This is a source-only release, which you must compile and install using the instructions found in *Note source-installation::, and in *Note mysql-cluster-installation::. You can download the GPL source tarball from the MySQL FTP site at `ftp://ftp.mysql.com/pub/mysql/download/cluster_telco/'. This Beta release incorporates all bugfixes and changes made in the previous MySQL Cluster NDB 6.3 release, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.22 (see *Note news-5-1-22::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Bugs fixed:* * A query against a table with *Note `TEXT': blob. or *Note `BLOB': blob. columns that would return more than a certain amount of data failed with `Got error 4350 'Transaction already aborted' from NDBCLUSTER'. (Bug #31482) This regression was introduced by Bug #29102. * *Cluster Replication*: In some cases, not all tables were properly initialized before the binary log thread was started. (Bug #31618)  File: manual.info, Node: mysql-cluster-news-5-1-22-ndb-6-3-4, Next: mysql-cluster-news-5-1-22-ndb-6-3-3, Prev: mysql-cluster-news-5-1-22-ndb-6-3-5, Up: mysql-cluster-news-6-3 17.7.4.47 Changes in MySQL Cluster NDB 6.3.4 (5.1.22-ndb-6.3.4) (15 October 2007) ................................................................................. This is a new Beta development release, fixing recently discovered bugs in previous MySQL Cluster NDB 6.3 releases. Obtaining MySQL Cluster NDB 6.3 This is a source-only release, which you must compile and install using the instructions found in *Note source-installation::, and in *Note mysql-cluster-installation::. You can download the GPL source tarball from the MySQL FTP site at `ftp://ftp.mysql.com/pub/mysql/download/cluster_telco/'. This Beta release incorporates all bugfixes and changes made in the previous MySQL Cluster NDB 6.3 release, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.22 (see *Note news-5-1-22::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * *Incompatible Change*: The `--ndb_optimized_node_selection' startup option for *Note `mysqld': mysqld. now permits a wider range of values and corresponding behaviors for SQL nodes when selecting a transaction coordinator. You should be aware that the default value and behavior as well as the value type used for this option have changed, and that you may need to update the setting used for this option in your `my.cnf' file prior to upgrading *Note `mysqld': mysqld. See *Note server-system-variables::, for more information. * *Replication*: On MySQL replication slaves having multiple network interfaces, it is now possible to set which interface to use for connecting to the master using the `MASTER_BIND='INTERFACE'' option in a *Note `CHANGE MASTER TO': change-master-to. statement. (Bug #25939, Bug #11746389) * *Cluster Replication*: A new configuration parameter `TimeBetweenEpochsTimeout' enables a timeout to be set for time between epochs. (Bug #31276) * *Cluster Replication*: A replication heartbeat mechanism has been added to facilitate monitoring. This provides an alternative to checking log files, making it possible to detect in real time when a slave has failed. Configuration of heartbeats is done using a new `MASTER_HEARTBEAT_PERIOD = INTERVAL' clause for the *Note `CHANGE MASTER TO': change-master-to. statement (see *Note change-master-to::); monitoring can be done by checking the values of the status variables `Slave_heartbeat_period' and `Slave_received_heartbeats' (see *Note server-status-variables::). The addition of replication heartbeats addresses a number of issues: * Relay logs were rotated every `slave_net_timeout' seconds even if no statements were being replicated. * *Note `SHOW SLAVE STATUS': show-slave-status. displayed an incorrect value for `Seconds_Behind_Master' following a *Note `FLUSH LOGS': flush. statement. * Replication master-slave connections used `slave_net_timeout' for connection timeouts. (Bug #20435, Bug #29309, Bug #30932) * *Cluster Replication*: Support for a new conflict resolution function `NDB$OLD()' has been added for handling simultaneous updates in multi-master and circular replication setups. A new status variable `Ndb_conflict_fn_old' tracks the number of times that updates are prevented from being applied due to this type of conflict resolution. See *Note mysql-cluster-replication-conflict-resolution::, for more information. * Additional checks were implemented to catch unsupported online *Note `ALTER TABLE': alter-table. operations. Currently it is not possible to reorder columns or to change the storage engine used for a table using online *Note `ALTER TABLE': alter-table. Some redundant checks made during online creation of indexes were removed. * A `--bind-address' option has been added to a number of MySQL client programs: *Note `mysql': mysql, *Note `mysqldump': mysqldump, *Note `mysqladmin': mysqladmin, *Note `mysqlbinlog': mysqlbinlog, *Note `mysqlcheck': mysqlcheck, *Note `mysqlimport': mysqlimport, and *Note `mysqlshow': mysqlshow. This is for use on a computer having multiple network interfaces, and enables you to choose which interface is used to connect to the MySQL server. A corresponding change was made to the `mysql_options()' C API function, which now has a `MYSQL_OPT_BIND' option for specifying the interface. The argument is a host name or IP address (specified as a string). *Bugs fixed:* * It was possible in some cases for a node group to be `lost' due to missed local checkpoints following a system restart. (Bug #31525) * *Note `NDB': mysql-cluster. tables having names containing nonalphanumeric characters (such as ``$'') were not discovered correctly. (Bug #31470) * A node failure during a local checkpoint could lead to a subsequent failure of the cluster during a system restart. (Bug #31257) * A cluster restart could sometimes fail due to an issue with table IDs. (Bug #30975) * Transaction timeouts were not handled well in some circumstances, leading to excessive number of transactions being aborted unnecessarily. (Bug #30379) * In some cases, the cluster managment server logged entries multiple times following a restart of *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. (Bug #29565) * *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. `--help' did not display any information about the `-a' option. (Bug #29509) * An interpreted program of sufficient size and complexity could cause all cluster data nodes to shut down due to buffer overruns. (Bug #29390) * The cluster log was formatted inconsistently and contained extraneous newline characters. (Bug #25064) * A transaction was not aborted following the failure of statement. (Bug #31320) * Online `ALTER' operations involving a column whose data type has an implicit default value left behind temporary `.frm' files, causing subsequent *Note `DROP DATABASE': drop-database. statements to fail. (Bug #31097) * Errors could sometimes occur during an online `ADD COLUMN' under load. (Bug #31082) * Transactions were committed prematurely when *Note `LOCK TABLE': lock-tables. and `SET autocommit = 0' were used together. (Bug #30996) * The *Note `mysqld_safe': mysqld-safe. script contained a syntax error. (Bug #30624)  File: manual.info, Node: mysql-cluster-news-5-1-22-ndb-6-3-3, Next: mysql-cluster-news-5-1-22-ndb-6-3-2, Prev: mysql-cluster-news-5-1-22-ndb-6-3-4, Up: mysql-cluster-news-6-3 17.7.4.48 Changes in MySQL Cluster NDB 6.3.3 (5.1.22-ndb-6.3.3) (20 September 2007) ................................................................................... This is a new Beta development release, fixing recently discovered bugs in previous MySQL Cluster NDB 6.3 releases. Obtaining MySQL Cluster NDB 6.3 This is a source-only release, which you must compile and install using the instructions found in *Note source-installation::, and in *Note mysql-cluster-installation::. You can download the GPL source tarball from the MySQL FTP site at `ftp://ftp.mysql.com/pub/mysql/download/cluster_telco/'. This Beta release incorporates all bugfixes and changes made in the previous MySQL Cluster NDB 6.3 release, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.22 (see *Note news-5-1-22::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * Mapping of *Note `NDB': mysql-cluster. error codes to MySQL storage engine error codes has been improved. (Bug #28423) * *Cluster Replication*: *Replication*: A server status variable `ndb_conflict_fn_max' now provides a count of the number of times that conflict resolution for MySQL Cluster Replication has been applied. See *Note mysql-cluster-replication-conflict-resolution::, for more information. *Bugs fixed:* * *Partitioning*: *Note `EXPLAIN PARTITIONS': explain. reported partition usage by queries on *Note `NDB': mysql-cluster. tables according to the standard MySQL hash function than the hash function used in the *Note `NDB': mysql-cluster. storage engine. (Bug #29550) * Attempting to restore a backup made on a cluster host using one endian to a machine using the other endian could cause the cluster to fail. (Bug #29674) * The description of the `--print' option provided in the output from *Note `ndb_restore `--help' ': mysql-cluster-programs-ndb-restore. was incorrect. (Bug #27683) * Restoring a backup made on a cluster host using one endian to a machine using the other endian failed for *Note `BLOB': blob. and *Note `DATETIME': datetime. columns. (Bug #27543, Bug #30024) * Errors could sometimes occur during an online `ADD COLUMN' under load. (Bug #31082)  File: manual.info, Node: mysql-cluster-news-5-1-22-ndb-6-3-2, Next: mysql-cluster-news-5-1-19-ndb-6-3-1, Prev: mysql-cluster-news-5-1-22-ndb-6-3-3, Up: mysql-cluster-news-6-3 17.7.4.49 Changes in MySQL Cluster NDB 6.3.2 (5.1.22-ndb-6.3.2) (07 September 2007) ................................................................................... This is a new Beta development release, fixing recently discovered bugs in previous MySQL Cluster NDB 6.3 releases. Obtaining MySQL Cluster NDB 6.3 This is a source-only release, which you must compile and install using the instructions found in *Note source-installation::, and in *Note mysql-cluster-installation::. You can download the GPL source tarball from the MySQL FTP site at `ftp://ftp.mysql.com/pub/mysql/download/cluster_telco/'. This Beta release incorporates all bugfixes and changes made in the previous MySQL Cluster NDB 6.3 release, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.22 (see *Note news-5-1-22::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * Online `ADD COLUMN', `ADD INDEX', and `DROP INDEX' operations can now be performed explicitly for *Note `NDB': mysql-cluster. tables--that is, without copying or locking of the affected tables--using `ALTER ONLINE TABLE'. Indexes can also be created and dropped online using *Note `CREATE INDEX': create-index. and *Note `DROP INDEX': drop-index, respectively, using the `ONLINE' keyword. You can force operations that would otherwise be performed online to be done offline using the `OFFLINE' keyword. Renaming of tables and columns for *Note `NDB': mysql-cluster. and `MyISAM' tables is performed in place without table copying. For more information, see *Note alter-table-online-operations::, *Note create-index::, and *Note drop-index::. * It is now possible to control whether fixed-width or variable-width storage is used for a given column of an *Note `NDB': mysql-cluster. table by means of the `COLUMN_FORMAT' specifier as part of the column's definition in a *Note `CREATE TABLE': create-table. or *Note `ALTER TABLE': alter-table. statement. It is also possible to control whether a given column of an *Note `NDB': mysql-cluster. table is stored in memory or on disk, using the `STORAGE' specifier as part of the column's definition in a *Note `CREATE TABLE': create-table. or *Note `ALTER TABLE': alter-table. statement. For permitted values and other information about `COLUMN_FORMAT' and `STORAGE', see *Note create-table::. * A new cluster management server startup option `--bind-address' makes it possible to restrict management client connections to *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. to a single host and port. For more information, see *Note mysql-cluster-programs-ndb-mgmd::. * *Cluster Replication*: Multi-way replication failover and recovery for *Note `NDB': mysql-cluster. is facilitated with the introduction of the `--ndb-log-orig' option. When *Note `mysqld': mysqld. is started with this option, the originating server ID and epoch of each binlog event is recorded in the `mysql.ndb_binlog_index' table, which now contains two additional columns `orig_server_id' and `orig_epoch' for storing this information. In such cases, a single epoch on a slave may be represented by multiple rows in the slave's `ndb_binlog_index' table, one for each epoch as it originated from a master. * *Cluster Replication*: The protocol for handling global checkpoints has been changed. It is now possible to control how often the GCI number is updated, and how often global checkpoints are written to disk, using the `TimeBetweenEpochs' configuration parameter. This improves the reliability and performance of MySQL Cluster Replication. GCPs handled using the new protocol are sometimes referred to as `micro-GCPs'. *Bugs fixed:* * When an *Note `NDB': mysql-cluster. event was left behind but the corresponding table was later recreated and received a new table ID, the event could not be dropped. (Bug #30877) * When creating an `NDB' table with a column that has `COLUMN_FORMAT = DYNAMIC', but the table tiself uses `ROW_FORMAT=FIXED', the table is considered dynamic, but any columns for which the row format is unspecified default to `FIXED'. Now in such cases the server issues the warning `Row format FIXED incompatible with dynamic attribute COLUMN_NAME'. (Bug #30276) * An insufficiently descriptive and potentially misleading Error 4006 (`Connect failure - out of connection objects...') was produced when either of the following two conditions occurred: 1. There were no more transaction records in the transaction coordinator 2. An *Note `NDB': mysql-cluster. object in the NDB API was initialized with insufficient parallelism Separate error messages are now generated for each of these two cases. (Bug #11313) * For micro-GCPs, the assignment of `fake' CGI events no longer cause buckets to be sent out of order. Now, when assigning a GCI to a non-GCI event (that is, creating a pseudo-GCI or `fake' CGI), the GCI that is to arrive is always initiated, even if no known GCI exists, which could occur in the event of a node failure. (Bug #30884)  File: manual.info, Node: mysql-cluster-news-5-1-19-ndb-6-3-1, Next: mysql-cluster-news-5-1-19-ndb-6-3-0, Prev: mysql-cluster-news-5-1-22-ndb-6-3-2, Up: mysql-cluster-news-6-3 17.7.4.50 Changes in MySQL Cluster NDB 6.3.1 (5.1.19-ndb-6.3.1) (04 July 2007) .............................................................................. This is a new Beta development release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.3 release. Obtaining MySQL Cluster NDB 6.3 This is a source-only release, which you must compile and install using the instructions found in *Note source-installation::, and in *Note mysql-cluster-installation::. You can download the GPL source tarball from the MySQL FTP site at `ftp://ftp.mysql.com/pub/mysql/download/cluster_telco/'. This Beta release incorporates all bugfixes and changes made in the previous MySQL Cluster NDB 6.3 release, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.19 (see *Note news-5-1-19::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Bugs fixed:* * Batching of transactions was not handled correctly in some cases. (Bug #29525)  File: manual.info, Node: mysql-cluster-news-5-1-19-ndb-6-3-0, Prev: mysql-cluster-news-5-1-19-ndb-6-3-1, Up: mysql-cluster-news-6-3 17.7.4.51 Changes in MySQL Cluster NDB 6.3.0 (5.1.19-ndb-6.3.0) (02 July 2007 Beta) ................................................................................... This is the first development release for MySQL Cluster NDB 6.3, based on version 6.3 of the *Note `NDBCLUSTER': mysql-cluster. storage engine. Obtaining MySQL Cluster NDB 6.3 This is a source-only release, which you must compile and install using the instructions found in *Note source-installation::, and in *Note mysql-cluster-installation::. You can download the GPL source tarball from the MySQL FTP site at `ftp://ftp.mysql.com/pub/mysql/download/cluster_telco/'. This Beta release incorporates all bugfixes and feature changes made in previous MySQL Cluster releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.19 (see *Note news-5-1-19::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * Reporting functionality has been significantly enhanced in this release: * A new configuration parameter `BackupReportFrequency' now makes it possible to cause the management client to provide status reports at regular intervals as well as for such reports to be written to the cluster log (depending on cluster event logging levels). * A new `REPORT' command has been added in the cluster management client. `REPORT BackupStatus' enables you to obtain a backup status report at any time during a backup. `REPORT MemoryUsage' reports the current data memory and index memory used by each data node. For more about the `REPORT' command, see *Note mysql-cluster-mgm-client-commands::. * *Note `ndb_restore': mysql-cluster-programs-ndb-restore. now provides running reports of its progress when restoring a backup. In addition, a complete report status report on the backup is written to the cluster log. * A new configuration parameter `ODirect' causes *Note `NDB': mysql-cluster. to attempt using `O_DIRECT' writes for LCP, backups, and redo logs, often lowering CPU usage. * *Cluster Replication*: This release implements conflict resolution, which makes it possible to determine on a per-table basis whether or not an update to a given row on the master should be applied on the slave. For more information, see *Note mysql-cluster-replication-conflict-resolution::.  File: manual.info, Node: mysql-cluster-news-6-2, Next: mysql-cluster-news-6-1, Prev: mysql-cluster-news-6-3, Up: mysql-cluster-news 17.7.5 Changes in MySQL Cluster NDB 6.2 --------------------------------------- * Menu: * mysql-cluster-news-5-1-51-ndb-6-2-19:: Changes in MySQL Cluster NDB 6.2.19 (5.1.51-ndb-6.2.19) (Not yet released) * mysql-cluster-news-5-1-34-ndb-6-2-18:: Changes in MySQL Cluster NDB 6.2.18 (5.1.34-ndb-6.2.18) (01 June 2009) * mysql-cluster-news-5-1-32-ndb-6-2-17:: Changes in MySQL Cluster NDB 6.2.17 (5.1.32-ndb-6.2.17) (19 October 2008) * mysql-cluster-news-5-1-28-ndb-6-2-16:: Changes in MySQL Cluster NDB 6.2.16 (5.1.28-ndb-6.2.16) (08 October 2008) * mysql-cluster-news-5-1-23-ndb-6-2-15:: Changes in MySQL Cluster NDB 6.2.15 (5.1.23-ndb-6.2.15) (22 May 2008) * mysql-cluster-news-5-1-23-ndb-6-2-14:: Changes in MySQL Cluster NDB 6.2.14 (5.1.23-ndb-6.2.14) (05 March 2008) * mysql-cluster-news-5-1-23-ndb-6-2-13:: Changes in MySQL Cluster NDB 6.2.13 (5.1.23-ndb-6.2.13) (22 February 2008) * mysql-cluster-news-5-1-23-ndb-6-2-12:: Changes in MySQL Cluster NDB 6.2.12 (5.1.23-ndb-6.2.12) (12 February 2008) * mysql-cluster-news-5-1-23-ndb-6-2-11:: Changes in MySQL Cluster NDB 6.2.11 (5.1.23-ndb-6.2.11) (28 January 2008) * mysql-cluster-news-5-1-23-ndb-6-2-10:: Changes in MySQL Cluster NDB 6.2.10 (5.1.23-ndb-6.2.10) (19 December 2007) * mysql-cluster-news-5-1-22-ndb-6-2-9:: Changes in MySQL Cluster NDB 6.2.9 (5.1.22-ndb-6.2.9) (22 November 2007) * mysql-cluster-news-5-1-22-ndb-6-2-8:: Changes in MySQL Cluster NDB 6.2.8 (5.1.22-ndb-6.2.8) (08 November 2007) * mysql-cluster-news-5-1-22-ndb-6-2-7:: Changes in MySQL Cluster NDB 6.2.7 (5.1.22-ndb-6.2.7) (10 October 2007) * mysql-cluster-news-5-1-22-ndb-6-2-6:: Changes in MySQL Cluster NDB 6.2.6 (5.1.22-ndb-6.2.6) (20 September 2007) * mysql-cluster-news-5-1-22-ndb-6-2-5:: Changes in MySQL Cluster NDB 6.2.5 (5.1.22-ndb-6.2.5) (06 September 2007 General Availability) * mysql-cluster-news-5-1-19-ndb-6-2-4:: Changes in MySQL Cluster NDB 6.2.4 (5.1.19-ndb-6.2.4) (04 July 2007) * mysql-cluster-news-5-1-19-ndb-6-2-3:: Changes in MySQL Cluster NDB 6.2.3 (5.1.19-ndb-6.2.3) (02 July 2007) * mysql-cluster-news-5-1-18-ndb-6-2-2:: Changes in MySQL Cluster NDB 6.2.2 (5.1.18-ndb-6.2.2) (07 May 2007) * mysql-cluster-news-5-1-18-ndb-6-2-1:: Changes in MySQL Cluster NDB 6.2.1 (5.1.18-ndb-6.2.1) (30 April 2007) * mysql-cluster-news-5-1-16-ndb-6-2-0:: Changes in MySQL Cluster NDB 6.2.0 (5.1.16-ndb-6.2.0) (03 March 2007 Beta) This section contains change history information for MySQL Cluster releases based on version 6.2 of the *Note `NDBCLUSTER': mysql-cluster. storage engine. For an overview of new features added in MySQL Cluster NDB 6.2, see *Note mysql-cluster-development-5-1-ndb-6-2::.  File: manual.info, Node: mysql-cluster-news-5-1-51-ndb-6-2-19, Next: mysql-cluster-news-5-1-34-ndb-6-2-18, Prev: mysql-cluster-news-6-2, Up: mysql-cluster-news-6-2 17.7.5.1 Changes in MySQL Cluster NDB 6.2.19 (5.1.51-ndb-6.2.19) (Not yet released) ................................................................................... This is a bugfix release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.2 release. This release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.2 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.51 (see *Note news-5-1-51::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * *Important Change*: More finely-grained control over restart-on-failure behavior is provided with two new data node configuration parameters `MaxStartFailRetries' and `StartFailRetryDelay'. `MaxStartFailRetries' limits the total number of retries made before giving up on starting the data node; `StartFailRetryDelay' sets the number of seconds between retry attempts. These parameters are used only if `StopOnError' is set to 0. For more information, see *Note mysql-cluster-ndbd-definition::. (Bug #54341) * *Important Change*: The `Id' configuration parameter used with MySQL Cluster management, data, and API nodes (including SQL nodes) is now deprecated, and the `NodeId' parameter (long available as a synonym for `Id' when configuring these types of nodes) should be used instead. `Id' continues to be supported for reasons of backward compatibility, but now generates a warning when used with these types of nodes, and is subject to removal in a future release of MySQL Cluster. This change affects the name of the configuration parameter only, establishing a clear preference for `NodeId' over `Id' in the `[mgmd]', `[ndbd]', `[mysql]', and `[api]' sections of the MySQL Cluster global configuration (`config.ini') file. The behavior of unique identifiers for management, data, and SQL and API nodes in MySQL Cluster has not otherwise been altered. The `Id' parameter as used in the `[computer]' section of the MySQL Cluster global configuration file is not affected by this change. * *Cluster API*: It is now possible to determine, using the *Note `ndb_desc': mysql-cluster-programs-ndb-desc. utility or the NDB API, which data nodes contain replicas of which partitions. For *Note `ndb_desc': mysql-cluster-programs-ndb-desc, a new `--extra-node-info' option is added to cause this information to be included in its output. A new method `Table::getFragmentNodes()' is added to the NDB API for obtaining this information programmatically. (Bug #51184) * On Solaris platforms, the MySQL Cluster management server and NDB API applications now use `CLOCK_REALTIME' as the default clock. (Bug #46183) *Bugs fixed:* * *Important Change*: The `--with-ndb-port-base' option for `configure' did not function correctly, and has been deprecated. Attempting to use this option produces the warning `Ignoring deprecated option --with-ndb-port-base'. Beginning with MySQL Cluster NDB 7.1.0, the deprecation warning itself is removed, and the `--with-ndb-port-base' option is simply handled as an unknown and invalid option if you try to use it. (Bug #47941) See also Bug #38502. * *Cluster Replication*: *Important Change*: In a MySQL Cluster acting as a replication slave and having multiple SQL nodes, only the SQL node receiving events directly from the master recorded DDL statements in its binary logs unless this SQL node also had binary logging enabled; otherwise, other SQL nodes in the slave cluster failed to log DDL statements, regardless of their individual `--log-bin' settings. The fix for this issue aligns binary logging of DDL statements with that of DML statements. In particular, you should take note of the following: * DDL and DML statements on the master cluster are logged with the server ID of the server that actually writes the log. * DDL and DML statements on the master cluster are logged by any attached *Note `mysqld': mysqld. that has binary logging enabled. * Replicated DDL and DML statements on the slave are logged by any attached mysqld that has both `--log-bin' and `--log-slave-updates' enabled. * Replicated DDL and DML statements are logged with the server ID of the original (master) MySQL server by any attached *Note `mysqld': mysqld. that has both `--log-bin' and `--log-slave-updates' enabled. Affect on upgrades When upgrading from a previous MySQL CLuster release, you should perform either one of the following: 1. Upgrade servers that are performing binary logging before those that are not; do not perform any DDL on `old' SQL nodes until all SQL nodes have been upgraded. 2. Make sure that `--log-slave-updates' is enabled on all SQL nodes performing binary logging prior to the upgrade, so that all DDL is captured. *Note*: Logging of DML statements was not affected by this issue. (Bug #45756) * *Packaging*: The `pkg' installer for MySQL Cluster on Solaris did not perform a complete installation due to an invalid directory reference in the postinstall script. (Bug #41998) * Two unused test files in `storage/ndb/test/sql' contained incorrect versions of the GNU Lesser General Public License. The files and the directory containing them have been removed. (Bug #11810156) See also Bug #11810224. * It was possible for a *Note `DROP DATABASE': drop-database. statement to remove *Note `NDB': mysql-cluster. hidden blob tables without removing the parent tables, with the result that the tables, although hidden to MySQL clients, were still visible in the output of *Note `ndb_show_tables': mysql-cluster-programs-ndb-show-tables. but could not be dropped using *Note `ndb_drop_table': mysql-cluster-programs-ndb-drop-table. (Bug #54788) * When performing an online alter table where 2 or more SQL nodes connected to the cluster were generating binary logs, an incorrect message could be sent from the data nodes, causing *Note `mysqld': mysqld. processes to crash. This problem was often difficult to detect, because restarting SQL node or data node processes could clear the error, and because the crash in *Note `mysqld': mysqld. did not occur until several minutes after the erroneous message was sent and received. (Bug #54168) * A table having the maximum number of attributes permitted could not be backed up using the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client. *Note*: The maximum number of attributes supported per table is not the same for all MySQL Cluster releases. See *Note mysql-cluster-limitations-database-objects::, to determine the maximum that applies in the release which you are using. (Bug #54155) * Creating a Disk Data table, dropping it, then creating an in-memory table and performing a restart, could cause data node processes to fail with errors in the `DBTUP' kernel block if the new table's internal ID was the same as that of the old Disk Data table. This could occur because undo log handling during the restart did not check that the table having this ID was now in-memory only. (Bug #53935) * A table created while `ndb_table_no_logging' was enabled was not always stored to disk, which could lead to a data node crash with `Error opening DIH schema files for table'. (Bug #53934) * An internal buffer allocator used by *Note `NDB': mysql-cluster. has the form `alloc(WANTED, MINIMUM)' and attempts to allocate WANTED pages, but is permitted to allocate a smaller number of pages, between WANTED and MINIMUM. However, this allocator could sometimes allocate fewer than MINIMUM pages, causing problems with multi-threaded building of ordered indexes. (Bug #53580) * With `engine_condition_pushdown' enabled, a query using `LIKE' on an *Note `ENUM': enum. column of an *Note `NDB': mysql-cluster. table failed to return any results. This issue is resolved by disabling `engine_condition_pushdown' when performing such queries. (Bug #53360) * `NDB' truncated a column declared as *Note `DECIMAL(65,0)': numeric-types. to a length of 64. Now such a column is accepted and handled correctly. In cases where the maximum length (65) is exceeded, `NDB' now raises an error instead of truncating. (Bug #53352) * When a watchdog shutdown occurred due to an error, the process was not terminated quickly enough, sometimes resulting in a hang. (To correct this, the internal `_exit()' function is now called in such situations, rather than `exit()'.) (Bug #53246) * Setting `DataMemory' higher than 4G on 32-bit platforms caused *Note `ndbd': mysql-cluster-programs-ndbd. to crash, instead of failing gracefully with an error. (Bug #52536, Bug #50928) * When running a *Note `SELECT': select. on an *Note `NDB': mysql-cluster. table with *Note `BLOB': blob. or *Note `TEXT': blob. columns, memory was allocated for the columns but was not freed until the end of the *Note `SELECT': select. This could cause problems with excessive memory usage when dumping (using for example *Note `mysqldump': mysqldump.) tables with such columns and having many rows, large column values, or both. (Bug #52313) See also Bug #56488, Bug #50310. * When using `NoOfReplicas' equal to 1 or 2, if data nodes from one node group were restarted 256 times and applications were running traffic such that it would encounter *Note `NDB': mysql-cluster. error 1204 (`Temporary failure, distribution changed'), the live node in the node group would crash, causing the cluster to crash as well. The crash occurred only when the error was encountered on the 256th restart; having the error on any previous or subsequent restart did not cause any problems. (Bug #50930) * If a query on an *Note `NDB': mysql-cluster. table compared a constant string value to a column, and the length of the string was greater than that of the column, condition pushdown did not work correctly. (The string was truncated to fit the column length before being pushed down.) Now in such cases, the condition is no longer pushed down. (Bug #49459) * When performing tasks that generated large amounts of I/O (such as when using *Note `ndb_restore': mysql-cluster-programs-ndb-restore.), an internal memory buffer could overflow, causing data nodes to fail with signal 6. Subsequent analysis showed that this buffer was not actually required, so this fix removes it. (Bug #48861) * Performing intensive inserts and deletes in parallel with a high scan load could a data node crashes due to a failure in the `DBACC' kernel block. This was because checking for when to perform bucket splits or merges considered the first 4 scans only. (Bug #48700) * The creation of an ordered index on a table undergoing DDL operations could cause a data node crash under certain timing-dependent conditions. (Bug #48604) * In certain cases, performing very large inserts on `NDB' tables when using *Note `ndbmtd': mysql-cluster-programs-ndbmtd. caused the memory allocations for ordered or unique indexes (or both) to be exceeded. This could cause aborted transactions and possibly lead to data node failures. (Bug #48037) See also Bug #48113. * When employing *Note `NDB': mysql-cluster. native backup to back up and restore an empty *Note `NDB': mysql-cluster. table that used a non-sequential `AUTO_INCREMENT' value, the `AUTO_INCREMENT' value was not restored correctly. (Bug #48005) * *Note `SHOW CREATE TABLE': show-create-table. did not display the `AUTO_INCREMENT' value for `NDB' tables having `AUTO_INCREMENT' columns. (Bug #47865) * Under some circumstances, when a scan encountered an error early in processing by the `DBTC' kernel block (see The `DBTC' Block (http://dev.mysql.com/doc/ndbapi/en/ndb-internals-kernel-blocks-dbtc.html)), a node could crash as a result. Such errors could be caused by applications sending incorrect data, or, more rarely, by a *Note `DROP TABLE': drop-table. operation executed in parallel with a scan. (Bug #47831) * When starting a node and synchronizing tables, memory pages were allocated even for empty fragments. In certain situations, this could lead to insufficient memory. (Bug #47782) * *Note `mysqld': mysqld. allocated an excessively large buffer for handling *Note `BLOB': blob. values due to overestimating their size. (For each row, enough space was allocated to accommodate _every_ *Note `BLOB': blob. or *Note `TEXT': blob. column value in the result set.) This could adversely affect performance when using tables containing *Note `BLOB': blob. or *Note `TEXT': blob. columns; in a few extreme cases, this issue could also cause the host system to run out of memory unexpectedly. (Bug #47574) See also Bug #47572, Bug #47573. * `NDBCLUSTER' uses a dynamically-allocated buffer to store *Note `BLOB': blob. or *Note `TEXT': blob. column data that is read from rows in MySQL Cluster tables. When an instance of the `NDBCLUSTER' table handler was recycled (this can happen due to table definition cache pressure or to operations such as *Note `FLUSH TABLES': flush. or *Note `ALTER TABLE': alter-table.), if the last row read contained blobs of zero length, the buffer was not freed, even though the reference to it was lost. This resulted in a memory leak. For example, consider the table defined and populated as shown here: CREATE TABLE t (a INT PRIMARY KEY, b LONGTEXT) ENGINE=NDB; INSERT INTO t VALUES (1, REPEAT('F', 20000)); INSERT INTO t VALUES (2, ''); Now execute repeatedly a *Note `SELECT': select. on this table, such that the zero-length *Note `LONGTEXT': blob. row is last, followed by a *Note `FLUSH TABLES': flush. statement (which forces the handler object to be re-used), as shown here: SELECT a, length(b) FROM bl ORDER BY a; FLUSH TABLES; Prior to the fix, this resulted in a memory leak proportional to the size of the stored *Note `LONGTEXT': blob. value each time these two statements were executed. (Bug #47573) See also Bug #47572, Bug #47574. * Large transactions involving joins between tables containing *Note `BLOB': blob. columns used excessive memory. (Bug #47572) See also Bug #47573, Bug #47574. * A variable was left uninitialized while a data node copied data from its peers as part of its startup routine; if the starting node died during this phase, this could lead a crash of the cluster when the node was later restarted. (Bug #47505) * *Note `NDB': mysql-cluster. stores blob column data in a separate, hidden table that is not accessible from MySQL. If this table was missing for some reason (such as accidental deletion of the file corresponding to the hidden table) when making a MySQL Cluster native backup, ndb_restore crashed when attempting to restore the backup. Now in such cases, ndb_restore fails with the error message `Table TABLE_NAME has blob column (COLUMN_NAME) with missing parts table in backup' instead. (Bug #47289) * For very large values of `MaxNoOfTables' + `MaxNoOfAttributes', the calculation for `StringMemory' could overflow when creating large numbers of tables, leading to *Note `NDB': mysql-cluster. error 773 (`Out of string memory, please modify StringMemory config parameter'), even when `StringMemory' was set to `100' (100 percent). (Bug #47170) * The default value for the `StringMemory' configuration parameter, unlike other MySQL Cluster configuration parameters, was not set in `ndb/src/mgmsrv/ConfigInfo.cpp'. (Bug #47166) * Signals from a failed API node could be received after an `API_FAILREQ' signal (see Operations and Signals (http://dev.mysql.com/doc/ndbapi/en/ndb-internals-ndb-protocol-operations-signals.html)) has been received from that node, which could result in invalid states for processing subsequent signals. Now, all pending signals from a failing API node are processed before any `API_FAILREQ' signal is received. (Bug #47039) See also Bug #44607. * Using triggers on *Note `NDB': mysql-cluster. tables caused `ndb_autoincrement_prefetch_sz' to be treated as having the NDB kernel's internal default value (32) and the value for this variable as set on the cluster's SQL nodes to be ignored. (Bug #46712) * Full table scans failed to execute when the cluster contained more than 21 table fragments. *Note*: The number of table fragments in the cluster can be calculated as the number of data nodes, times 8 (that is, times the value of the internal constant `MAX_FRAG_PER_NODE'), divided by the number of replicas. Thus, when `NoOfReplicas = 1' at least 3 data nodes were required to trigger this issue, and when `NoOfReplicas = 2' at least 4 data nodes were required to do so. (Bug #46490) * Ending a line in the `config.ini' file with an extra semicolon character (`;') caused reading the file to fail with a parsing error. (Bug #46242) * When combining an index scan and a delete with a primary key delete, the index scan and delete failed to initialize a flag properly. This could in rare circumstances cause a data node to crash. (Bug #46069) * Problems could arise when using *Note `VARCHAR': char. columns whose size was greater than 341 characters and which used the `utf8_unicode_ci' collation. In some cases, this combination of conditions could cause certain queries and *Note `OPTIMIZE TABLE': optimize-table. statements to crash *Note `mysqld': mysqld. (Bug #45053) * Running an *Note `ALTER TABLE': alter-table. statement while an *Note `NDB': mysql-cluster. backup was in progress caused *Note `mysqld': mysqld. to crash. (Bug #44695) * If a node failed while sending a fragmented long signal, the receiving node did not free long signal assembly resources that it had allocated for the fragments of the long signal that had already been received. (Bug #44607) * When performing auto-discovery of tables on individual SQL nodes, `NDBCLUSTER' attempted to overwrite existing `MyISAM' `.frm' files and corrupted them. Workaround In the *Note `mysql': mysql. client, create a new table (`t2') with same definition as the corrupted table (`t1'). Use your system shell or file manager to rename the old `.MYD' file to the new file name (for example, `mv t1.MYD t2.MYD'). In the *Note `mysql': mysql. client, repair the new table, drop the old one, and rename the new table using the old file name (for example, *Note `RENAME TABLE t2 TO t1': rename-table.). (Bug #42614) * When starting a cluster with a great many tables, it was possible for MySQL client connections as well as the slave SQL thread to issue DML statements against MySQL Cluster tables before *Note `mysqld': mysqld. had finished connecting to the cluster and making all tables writeable. This resulted in `Table ... is read only' errors for clients and the Slave SQL thread. This issue is fixed by introducing the `--ndb-wait-setup' option for the MySQL server. This provides a configurable maximum amount of time that *Note `mysqld': mysqld. waits for all *Note `NDB': mysql-cluster. tables to become writeable, before enabling MySQL clients or the slave SQL thread to connect. (Bug #40679) See also Bug #46955. * Running *Note `ndb_restore': mysql-cluster-programs-ndb-restore. with the `--print' or `--print_log' option could cause it to crash. (Bug #40428, Bug #33040) * When a slash character (`/') was used as part of the name of an index on an *Note `NDB': mysql-cluster. table, attempting to execute a *Note `TRUNCATE TABLE': truncate-table. statement on the table failed with the error `Index not found', and the table was rendered unusable. (Bug #38914) * When building MySQL Cluster, it was possible to configure the build using `--with-ndb-port' without supplying a port number. Now in such cases, `configure' fails with an error. (Bug #38502) See also Bug #47941. * An insert on an *Note `NDB': mysql-cluster. table was not always flushed properly before performing a scan. One way in which this issue could manifest was that `LAST_INSERT_ID()' sometimes failed to return correct values when using a trigger on an *Note `NDB': mysql-cluster. table. (Bug #38034) * If the cluster crashed during the execution of a *Note `CREATE LOGFILE GROUP': create-logfile-group. statement, the cluster could not be restarted afterward. (Bug #36702) See also Bug #34102. * Some joins on large *Note `NDB': mysql-cluster. tables having *Note `TEXT': blob. or *Note `BLOB': blob. columns could cause *Note `mysqld': mysqld. processes to leak memory. The joins did not need to reference the *Note `TEXT': blob. or *Note `BLOB': blob. columns directly for this issue to occur. (Bug #36701) * When the MySQL server SQL mode included `STRICT_TRANS_TABLES', storage engine warnings and error codes specific to `NDB' were returned when errors occurred, instead of the MySQL server errors and error codes expected by some programming APIs (such as Connector/J) and applications. (Bug #35990) * On Mac OS X 10.5, commands entered in the management client failed and sometimes caused the client to hang, although management client commands invoked using the `--execute' (or `-e') option from the system shell worked normally. For example, the following command failed with an error and hung until killed manually, as shown here: ndb_mgm> SHOW `Warning, event thread startup failed, degraded printouts as result, errno=36' ^C However, the same management client command, invoked from the system shell as shown here, worked correctly: shell> ndb_mgm -e "SHOW" (Bug #35751) See also Bug #34438. * When a copying operation exhausted the available space on a data node while copying large *Note `BLOB': blob. columns, this could lead to failure of the data node and a `Table is full' error on the SQL node which was executing the operation. Examples of such operations could include an *Note `ALTER TABLE': alter-table. that changed an *Note `INT': numeric-types. column to a *Note `BLOB': blob. column, or a bulk insert of *Note `BLOB': blob. data that failed due to running out of space or to a duplicate key error. (Bug #34583, Bug #48040) See also Bug #41674, Bug #45768. * Trying to insert more rows than would fit into an `NDB' table caused data nodes to crash. Now in such situations, the insert fails gracefully with error 633 `Table fragment hash index has reached maximum possible size'. (Bug #34348) * The error message text for *Note `NDB': mysql-cluster. error code 410 (`REDO log files overloaded...') was truncated. (Bug #23662) * *Replication*: When *Note `mysqlbinlog': mysqlbinlog. `--verbose' was used to read a binary log that had been written using row-based format, the output for events that updated some but not all columns of tables was not correct. (Bug #47323) * *Replication*: In some cases, a *Note `STOP SLAVE': stop-slave. statement could cause the replication slave to crash. This issue was specific to MySQL on Windows or Macintosh platforms. (Bug #45238, Bug #45242, Bug #45243, Bug #46013, Bug #46014, Bug #46030) See also Bug #40796. * *Disk Data*: As an optimization when inserting a row to an empty page, the page is not read, but rather simply initialized. However, this optimzation was performed in all cases when an empty row was inserted, even though it should have been done only if it was the first time that the page had been used by a table or fragment. This is because, if the page had been in use, and then all records had been released from it, the page still needed to be read to learn its log sequence number (LSN). This caused problems only if the page had been flushed using an incorrect LSN and the data node failed before any local checkpoint was completed--which would removed any need to apply the undo log, hence the incorrect LSN was ignored. The user-visible result of the incorrect LSN was that it caused the data node to fail during a restart. It was perhaps also possible (although not conclusively proven) that this issue could lead to incorrect data. (Bug #54986) * *Disk Data*: Inserts of blob column values into a Disk Data table that exhausted the tablespace resulted in misleading error messages about rows not being found in the table rather than the expected error `Out of extents, tablespace full'. (Bug #48113) See also Bug #48037, Bug #41674. * *Disk Data*: A local checkpoint of an empty fragment could cause a crash during a system restart which was based on that LCP. (Bug #47832) See also Bug #41915. * *Disk Data*: Calculation of free space for Disk Data table fragments was sometimes done incorrectly. This could lead to unnecessary allocation of new extents even when sufficient space was available in existing ones for inserted data. In some cases, this might also lead to crashes when restarting data nodes. *Note*: This miscalculation was not reflected in the contents of the *Note `INFORMATION_SCHEMA.FILES': files-table. table, as it applied to extents allocated to a fragment, and not to a file. (Bug #47072) * *Disk Data*: If the value set in the `config.ini' file for `FileSystemPathDD', `FileSystemPathDataFiles', or `FileSystemPathUndoFiles' was identical to the value set for `FileSystemPath', that parameter was ignored when starting the data node with `--initial' option. As a result, the Disk Data files in the corresponding directory were not removed when performing an initial start of the affected data node or data nodes. (Bug #46243) * *Disk Data*: Repeatedly creating and then dropping Disk Data tables could eventually lead to data node failures. (Bug #45794, Bug #48910) * *Disk Data*: When a crash occurs due to a problem in Disk Data code, the currently active page list is printed to `stdout' (that is, in one or more `ndb_NODEID_out.log' files). One of these lists could contain an endless loop; this caused a printout that was effectively never-ending. Now in such cases, a maximum of 512 entries is printed from each list. (Bug #42431) * *Cluster Replication*: When `expire_logs_days' was set, the thread performing the purge of the log files could deadlock, causing all binary log operations to stop. (Bug #49536) * *Cluster Replication*: When using multiple active replication channels, it was sometimes possible that a node group would fail on the slave cluster, causing the slave cluster to shut down. (Bug #47935) * *Cluster Replication*: When recording a binary log using the `--ndb-log-update-as-write' and `--ndb-log-updated-only' options (both enabled by default) and later attempting to apply that binary log with *Note `mysqlbinlog': mysqlbinlog, any operations that were played back from the log but which updated only some (but not all) columns caused any columns that were not updated to be reset to their default values. (Bug #47674) See also Bug #47323, Bug #46662. * *Cluster Replication*: *Note `mysqlbinlog': mysqlbinlog. failed to apply correctly a binary log that had been recorded using `--ndb-log-update-as-write=1'. (Bug #46662) See also Bug #47323, Bug #47674. * *Cluster Replication*: When inserting rows into the `mysql.ndb_binlog_index' table, duplicate key errors occurred when the size of the epoch number (a 64-bit integer) exceeded 2^53. This happened because the `NDB' storage engine handler called the wrong overloaded variant of a MySQL Server internal API (the `Field::store()' method), which resulted in the epoch being mapped to a 64-bit double precision floating point number and a corresponding loss of accuracy for numbers greater than 2^53. (Bug #35217) * *Cluster API*: When reading blob data with lock mode `LM_SimpleRead', the lock was not upgraded as expected. (Bug #51034) * *Cluster API*: When a DML operation failed due to a uniqueness violation on an *Note `NDB': mysql-cluster. table having more than one unique index, it was difficult to determine which constraint caused the failure; it was necessary to obtain an `NdbError' object, then decode its `details' property, which in could lead to memory management issues in application code. To help solve this problem, a new API method `Ndb::getNdbErrorDetail()' is added, providing a well-formatted string containing more precise information about the index that caused the unque constraint violation. The following additional changes are also made in the NDB API: * Use of `NdbError.details' is now deprecated in favor of the new method. * The `NdbDictionary::listObjects()' method has been modified to provide more information. For more information, see `Ndb::getNdbErrorDetail()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndb-methods.html#ndb-ndb-getndberrordetail), The `NdbError' Structure (http://dev.mysql.com/doc/ndbapi/en/ndb-ndberror.html#ndb-ndberror), and `Dictionary::listObjects()' (http://dev.mysql.com/doc/ndbapi/en/ndb-dictionary-methods.html#ndb-dictionary-listobjects). (Bug #48851) * *Cluster API*: The NDB API methods `Dictionary::listEvents()', `Dictionary::listIndexes()', `Dictionary::listObjects()', and `NdbOperation::getErrorLine()' formerly had both `const' and non-`const' variants. The non-`const' versions of these methods have been removed. In addition, the `NdbOperation::getBlobHandle()' method has been re-implemented to provide consistent internal semantics. (Bug #47798) * *Cluster API*: In some circumstances, if an API node encountered a data node failure between the creation of a transaction and the start of a scan using that transaction, then any subsequent calls to `startTransaction()' and `closeTransaction()' could cause the same transaction to be started and closed repeatedly. (Bug #47329) * *Cluster API*: A duplicate read of a column caused NDB API applications to crash. (Bug #45282) * *Cluster API*: Performing multiple operations using the same primary key within the same `NdbTransaction::execute()' call could lead to a data node crash. *Note*: This fix does not make change the fact that performing multiple operations using the same primary key within the same `execute()' is not supported; because there is no way to determine the order of such operations, the result of such combined operations remains undefined. (Bug #44065) See also Bug #44015. * *Cluster API*: The error handling shown in the example file `ndbapi_scan.cpp' included with the MySQL Cluster distribution was incorrect. (Bug #39573) * *Cluster API*: When using blobs, calling `getBlobHandle()' requires the full key to have been set using `equal()', because `getBlobHandle()' must access the key for adding blob table operations. However, if `getBlobHandle()' was called without first setting all parts of the primary key, the application using it crashed. Now, an appropriate error code is returned instead. (Bug #28116, Bug #48973) * *API*: The fix for Bug#24507 could lead in some cases to client application failures due to a race condition. Now the server waits for the `dummy' thread to return before exiting, thus making sure that only one thread can initialize the POSIX threads library. (Bug #42850) * On some Unix/Linux platforms, an error during build from source could be produced, referring to a missing `LT_INIT' program. This is due to versions of `libtool' 2.1 and earlier. (Bug #51009) * On Mac OS X or Windows, sending a `SIGHUP' signal to the server or an asynchronous flush (triggered by `flush_time') caused the server to crash. (Bug #47525) * 1) In rare cases, if a thread was interrupted during a *Note `FLUSH PRIVILEGES': flush. operation, a debug assertion occurred later due to improper diagnostics area setup. 2) A *Note `KILL': kill. operation could cause a console error message referring to a diagnostic area state without first ensuring that the state existed. (Bug #33982) * When using the *Note `ARCHIVE': archive-storage-engine. storage engine, `SHOW TABLE STATUS' displayed incorrect information for `Max_data_length', `Data_length' and `Avg_row_length'. (Bug #29203) * Installation of MySQL on Windows would fail to set the correct location for the character set files, which could lead to *Note `mysqld': mysqld. and *Note `mysql': mysql. failing to initialize properly. (Bug #17270)  File: manual.info, Node: mysql-cluster-news-5-1-34-ndb-6-2-18, Next: mysql-cluster-news-5-1-32-ndb-6-2-17, Prev: mysql-cluster-news-5-1-51-ndb-6-2-19, Up: mysql-cluster-news-6-2 17.7.5.2 Changes in MySQL Cluster NDB 6.2.18 (5.1.34-ndb-6.2.18) (01 June 2009) ............................................................................... This is a bugfix release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.2 release. This release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.2 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.34 (see *Note news-5-1-34::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Bugs fixed:* * *Important Change*: *Partitioning*: User-defined partitioning of an *Note `NDBCLUSTER': mysql-cluster. table without any primary key sometimes failed, and could cause *Note `mysqld': mysqld. to crash. Now, if you wish to create an *Note `NDBCLUSTER': mysql-cluster. table with user-defined partitioning, the table must have an explicit primary key, and all columns listed in the partitioning expression must be part of the primary key. The hidden primary key used by the *Note `NDBCLUSTER': mysql-cluster. storage engine is not sufficient for this purpose. However, if the list of columns is empty (that is, the table is defined using `PARTITION BY [LINEAR] KEY()'), then no explicit primary key is required. This change does not effect the partitioning of tables using any storage engine other than *Note `NDBCLUSTER': mysql-cluster. (Bug #40709) * An internal NDB API buffer was not properly initialized. (Bug #44977) * When a data node had written its GCI marker to the first page of a megabyte, and that node was later killed during restart after having processed that page (marker) but before completing a LCP, the data node could fail with file system errors. (Bug #44952) See also Bug #42564, Bug #44291. * Inspection of the code revealed that several assignment operators (`=') were used in place of comparison operators (`==') in `DbdihMain.cpp'. (Bug #44567) See also Bug #44570. * It was possible for NDB API applications to insert corrupt data into the database, which could subquently lead to data node crashes. Now, stricter checking is enforced on input data for inserts and updates. (Bug #44132) * `TransactionDeadlockDetectionTimeout' values less than 100 were treated as 100. This could cause scans to time out unexpectedly. (Bug #44099) * The file `ndberror.c' contained a C++-style comment, which caused builds to fail with some C compilers. (Bug #44036) * A race condition could occur when a data node failed to restart just before being included in the next global checkpoint. This could cause other data nodes to fail. (Bug #43888) * When trying to use a data node with an older version of the management server, the data node crashed on startup. (Bug #43699) * Using indexes containing variable-sized columns could lead to internal errors when the indexes were being built. (Bug #43226) * In some cases, data node restarts during a system restart could fail due to insufficient redo log space. (Bug #43156) * Some queries using combinations of logical and comparison operators on an indexed column in the `WHERE' clause could fail with the error `Got error 4541 'IndexBound has no bound information' from NDBCLUSTER'. (Bug #42857) * *Note `ndb_restore `--print_data'': mysql-cluster-programs-ndb-restore. did not handle *Note `DECIMAL': numeric-types. columns correctly. (Bug #37171) * The output of *Note `ndbd `--help'': mysql-cluster-programs-ndbd. did not provide clear information about the program's `--initial' and `--initial-start' options. (Bug #28905) * It was theoretically possible for the value of a nonexistent column to be read as `NULL', rather than causing an error. (Bug #27843) * When aborting an operation involving both an insert and a delete, the insert and delete were aborted separately. This was because the transaction coordinator did not know that the operations affected on same row, and, in the case of a committed-read (tuple or index) scan, the abort of the insert was performed first, then the row was examined after the insert was aborted but before the delete was aborted. In some cases, this would leave the row in a inconsistent state. This could occur when a local checkpoint was performed during a backup. This issue did not affect primary ley operations or scans that used locks (these are serialized). After this fix, for ordered indexes, all operations that follow the operation to be aborted are now also aborted. * *Disk Data*: *Partitioning*: An *Note `NDB': mysql-cluster. table created with a very large value for the `MAX_ROWS' option could--if this table was dropped and a new table with fewer partitions, but having the same table ID, was created--cause *Note `ndbd': mysql-cluster-programs-ndbd. to crash when performing a system restart. This was because the server attempted to examine each partition whether or not it actually existed. (Bug #45154) See also Bug #58638. * *Disk Data*: During a checkpoint, restore points are created for both the on-disk and in-memory parts of a Disk Data table. Under certain rare conditions, the in-memory restore point could include or exclude a row that should have been in the snapshot. This would later lead to a crash during or following recovery. (Bug #41915) See also Bug #47832. * *Disk Data*: When a log file group had an undo log file whose size was too small, restarting data nodes failed with `Read underflow' errors. As a result of this fix, the minimum permitted `INTIAL_SIZE' for an undo log file is now `1M' (1 megabyte). (Bug #29574) * *Disk Data*: This fix supercedes and improves on an earlier fix made for this bug in MySQL 5.1.18. (Bug #24521) * *Cluster Replication*: A failure when setting up replication events could lead to subsequent data node failures. (Bug #44915) * *Cluster API*: If the largest offset of a `RecordSpecification' used for an `NdbRecord' object was for the `NULL' bits (and thus not a column), this offset was not taken into account when calculating the size used for the `RecordSpecification'. This meant that the space for the `NULL' bits could be overwritten by key or other information. (Bug #43891) * *Cluster API*: The default `NdbRecord' structures created by `NdbDictionary' could have overlapping null bits and data fields. (Bug #43590) * *Cluster API*: When performing insert or write operations, `NdbRecord' permits key columns to be specified in both the key record and in the attribute record. Only one key column value for each key column should be sent to the NDB kernel, but this was not guaranteed. This is now ensured as follows: For insert and write operations, key column values are taken from the key record; for scan takeover update operations, key column values are taken from the attribute record. (Bug #42238) * *Cluster API*: Ordered index scans using `NdbRecord' formerly expressed a `BoundEQ' range as separate lower and upper bounds, resulting in 2 copies of the column values being sent to the NDB kernel. Now, when a range is specified by `NdbScanOperation::setBound()', the passed pointers, key lengths, and inclusive bits are compared, and only one copy of the equal key columns is sent to the kernel. This makes such operations more efficient, as half the amount of `KeyInfo' is now sent for a `BoundEQ' range as before. (Bug #38793)  File: manual.info, Node: mysql-cluster-news-5-1-32-ndb-6-2-17, Next: mysql-cluster-news-5-1-28-ndb-6-2-16, Prev: mysql-cluster-news-5-1-34-ndb-6-2-18, Up: mysql-cluster-news-6-2 17.7.5.3 Changes in MySQL Cluster NDB 6.2.17 (5.1.32-ndb-6.2.17) (19 October 2008) .................................................................................. This is a bugfix release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.2 release. This release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.2 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.32 (see *Note news-5-1-32::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * *Important Change*: Formerly, when the management server failed to create a transporter for a data node connection, `net_write_timeout' seconds elapsed before the data node was actually permitted to disconnect. Now in such cases the disconnection occurs immediately. (Bug #41965) See also Bug #41713. * *Important Change*: *Replication*: *Note `RESET MASTER': reset-master. and *Note `RESET SLAVE': reset-slave. now reset the values shown for `Last_IO_Error', `Last_IO_Errno', `Last_SQL_Error', and `Last_SQL_Errno' in the output of *Note `SHOW SLAVE STATUS': show-slave-status. (Bug #34654) See also Bug #44270. * *Cluster Replication*: *Important Note*: This release of MySQL Cluster derives in part from MySQL 5.1.29, where the default value for the `--binlog-format' option changed to `STATEMENT'. That change does _not_ affect this or future MySQL Cluster NDB 6.x releases, where the default value for this option remains `MIXED', since MySQL Cluster Replication does not work with the statement-based format. (Bug #40586) * *Disk Data*: It is now possible to specify default locations for Disk Data data files and undo log files, either together or separately, using the data node configuration parameters `FileSystemPathDD', `FileSystemPathDataFiles', and `FileSystemPathUndoFiles'. For information about these configuration parameters, see `Disk Data file system parameters'. It is also now possible to specify a log file group, tablespace, or both, that is created when the cluster is started, using the `InitialLogFileGroup' and `InitialTablespace' data node configuration parameters. For information about these configuration parameters, see `Disk Data object creation parameters'. *Bugs fixed:* * *Performance*: Updates of the `SYSTAB_0' system table to obtain a unique identifier did not use transaction hints for tables having no primary key. In such cases the NDB kernel used a cache size of 1. This meant that each insert into a table not having a primary key required an update of the corresponding `SYSTAB_0' entry, creating a potential performance bottleneck. With this fix, inserts on `NDB' tables without primary keys can be under some conditions be performed up to 100% faster than previously. (Bug #39268) * *Packaging*: Packages for MySQL Cluster were missing the `libndbclient.so' and `libndbclient.a' files. (Bug #42278) * *Partitioning*: Executing `ALTER TABLE ... REORGANIZE PARTITION' on an *Note `NDBCLUSTER': mysql-cluster. table having only one partition caused *Note `mysqld': mysqld. to crash. (Bug #41945) See also Bug #40389. * *Cluster API*: Failed operations on *Note `BLOB': blob. and *Note `TEXT': blob. columns were not always reported correctly to the originating SQL node. Such errors were sometimes reported as being due to timeouts, when the actual problem was a transporter overload due to insufficient buffer space. (Bug #39867, Bug #39879) * Backup IDs greater than 2^31 were not handled correctly, causing negative values to be used in backup directory names and printouts. (Bug #43042) * When using *Note `ndbmtd': mysql-cluster-programs-ndbmtd, NDB kernel threads could hang while trying to start the data nodes with `LockPagesInMainMemory' set to 1. (Bug #43021) * When using multiple management servers and starting several API nodes (possibly including one or more SQL nodes) whose connectstrings listed the management servers in different order, it was possible for 2 API nodes to be assigned the same node ID. When this happened it was possible for an API node not to get fully connected, consequently producing a number of errors whose cause was not easily recognizable. (Bug #42973) * *Note `ndb_error_reporter': mysql-cluster-programs-ndb-error-reporter. worked correctly only with GNU `tar'. (With other versions of `tar', it produced empty archives.) (Bug #42753) * Triggers on *Note `NDBCLUSTER': mysql-cluster. tables caused such tables to become locked. (Bug #42751) See also Bug #16229, Bug #18135. * When performing more than 32 index or tuple scans on a single fragment, the scans could be left hanging. This caused unnecessary timeouts, and in addition could possibly lead to a hang of an LCP. (Bug #42559) * A data node failure that occurred between calls to `NdbIndexScanOperation::readTuples(SF_OrderBy)' and `NdbTransaction::execute()' was not correctly handled; a subsequent call to `nextResult()' caused a null pointer to be deferenced, leading to a segfault in *Note `mysqld': mysqld. (Bug #42545) * Issuing `SHOW GLOBAL STATUS LIKE 'NDB%'' before *Note `mysqld': mysqld. had connected to the cluster caused a segmentation fault. (Bug #42458) * Data node failures that occurred before all data nodes had connected to the cluster were not handled correctly, leading to additional data node failures. (Bug #42422) * When a cluster backup failed with Error 1304 (Node NODE_ID1: Backup request from NODE_ID2 failed to start), no clear reason for the failure was provided. As part of this fix, MySQL Cluster now retries backups in the event of sequence errors. (Bug #42354) See also Bug #22698. * Issuing *Note `SHOW ENGINE NDBCLUSTER STATUS': show-engine. on an SQL node before the management server had connected to the cluster caused *Note `mysqld': mysqld. to crash. (Bug #42264) * A maximum of 11 `TUP' scans were permitted in parallel. (Bug #42084) * Trying to execute an *Note `ALTER ONLINE TABLE ... ADD COLUMN': alter-table. statement while inserting rows into the table caused *Note `mysqld': mysqld. to crash. (Bug #41905) * If the master node failed during a global checkpoint, it was possible in some circumstances for the new master to use an incorrect value for the global checkpoint index. This could occur only when the cluster used more than one node group. (Bug #41469) * API nodes disconnected too agressively from cluster when data nodes were being restarted. This could sometimes lead to the API node being unable to access the cluster at all during a rolling restart. (Bug #41462) * An abort path in the `DBLQH' kernel block failed to release a commit acknowledgment marker. This meant that, during node failure handling, the local query handler could be added multiple times to the marker record which could lead to additional node failures due an array overflow. (Bug #41296) * During node failure handling (of a data node other than the master), there was a chance that the master was waiting for a `GCP_NODEFINISHED' signal from the failed node after having received it from all other data nodes. If this occurred while the failed node had a transaction that was still being committed in the current epoch, the master node could crash in the `DBTC' kernel block when discovering that a transaction actually belonged to an epoch which was already completed. (Bug #41295) * If a transaction was aborted during the handling of a data node failure, this could lead to the later handling of an API node failure not being completed. (Bug #41214) * Given a MySQL Cluster containing no data (that is, whose data nodes had all been started using `--initial', and into which no data had yet been imported) and having an empty backup directory, executing `START BACKUP' with a user-specified backup ID caused the data nodes to crash. (Bug #41031) * Issuing `EXIT' in the management client sometimes caused the client to hang. (Bug #40922) * Redo log creation was very slow on some platforms, causing MySQL Cluster to start more slowly than necessary with some combinations of hardware and operating system. This was due to all write operations being synchronized to disk while creating a redo log file. Now this synchronization occurs only after the redo log has been created. (Bug #40734) * Transaction failures took longer to handle than was necessary. When a data node acting as transaction coordinator (TC) failed, the surviving data nodes did not inform the API node initiating the transaction of this until the failure had been processed by all protocols. However, the API node needed only to know about failure handling by the transaction protocol--that is, it needed to be informed only about the TC takeover process. Now, API nodes (including MySQL servers acting as cluster SQL nodes) are informed as soon as the TC takeover is complete, so that it can carry on operating more quickly. (Bug #40697) * It was theoretically possible for stale data to be read from *Note `NDBCLUSTER': mysql-cluster. tables when the transaction isolation level was set to `ReadCommitted'. (Bug #40543) * In some cases, *Note `NDB': mysql-cluster. did not check correctly whether tables had changed before trying to use the query cache. This could result in a crash of the debug MySQL server. (Bug #40464) * Restoring a MySQL Cluster from a dump made using *Note `mysqldump': mysqldump. failed due to a spurious error: `Can't execute the given command because you have active locked tables or an active transaction'. (Bug #40346) * `O_DIRECT' was incorrectly disabled when making MySQL Cluster backups. (Bug #40205) * Events logged after setting `ALL CLUSTERLOG STATISTICS=15' in the management client did not always include the node ID of the reporting node. (Bug #39839) * Start phase reporting was inconsistent between the management client and the cluster log. (Bug #39667) * The MySQL Query Cache did not function correctly with *Note `NDBCLUSTER': mysql-cluster. tables containing *Note `TEXT': blob. columns. (Bug #39295) * A segfault in `Logger::Log' caused *Note `ndbd': mysql-cluster-programs-ndbd. to hang indefinitely. This fix improves on an earlier one for this issue, first made in MySQL Cluster NDB 6.2.16 and MySQL Cluster NDB 6.3.17. (Bug #39180) See also Bug #38609. * Memory leaks could occur in handling of strings used for storing cluster metadata and providing output to users. (Bug #38662) * In the event that a MySQL Cluster backup failed due to file permissions issues, conflicting reports were issued in the management client. (Bug #34526) * A duplicate key or other error raised when inserting into an *Note `NDBCLUSTER': mysql-cluster. table caused the current transaction to abort, after which any SQL statement other than a *Note `ROLLBACK': commit. failed. With this fix, the *Note `NDBCLUSTER': mysql-cluster. storage engine now performs an implicit rollback when a transaction is aborted in this way; it is no longer necessary to issue an explicit *Note `ROLLBACK': commit. statement, and the next statement that is issued automatically begins a new transaction. *Note*: It remains necessary in such cases to retry the complete transaction, regardless of which statement caused it to be aborted. (Bug #32656) See also Bug #47654. * Error messages for *Note `NDBCLUSTER': mysql-cluster. error codes 1224 and 1227 were missing. (Bug #28496) * *Partitioning*: A query on a user-partitioned table caused MySQL to crash, where the query had the following characteristics: * The query's `WHERE' clause referenced an indexed column that was also in the partitioning key. * The query's `WHERE' clause included a value found in the partition. * The query's `WHERE' clause used the `<' or `<>' operators to compare with the indexed column's value with a constant. * The query used an `ORDER BY' clause, and the same indexed column was used in the `ORDER BY' clause. * The `ORDER BY' clause used an explcit or implicit `ASC' sort priority. Two examples of such a query are given here, where `a' represents an indexed column used in the table's partitioning key: 1. SELECT * FROM TABLE WHERE a < CONSTANT ORDER BY a; 2. SELECT * FROM TABLE WHERE a <> CONSTANT ORDER BY a; (Bug #40954) This regression was introduced by Bug #30573, Bug #33257, Bug #33555. * *Partitioning*: Dropping or creating an index on a partitioned table managed by the `InnoDB' Plugin locked the table. (Bug #37453) * *Disk Data*: It was not possible to add an in-memory column online to a table that used a table-level or column-level `STORAGE DISK' option. The same issue prevented `ALTER ONLINE TABLE ... REORGANIZE PARTITION' from working on Disk Data tables. (Bug #42549) * *Disk Data*: Issuing concurrent *Note `CREATE TABLESPACE': create-tablespace, *Note `ALTER TABLESPACE': alter-tablespace, *Note `CREATE LOGFILE GROUP': create-logfile-group, or *Note `ALTER LOGFILE GROUP': alter-logfile-group. statements on separate SQL nodes caused a resource leak that led to data node crashes when these statements were used again later. (Bug #40921) * *Disk Data*: Disk-based variable-length columns were not always handled like their memory-based equivalents, which could potentially lead to a crash of cluster data nodes. (Bug #39645) * *Disk Data*: Creating a Disk Data tablespace with a very large extent size caused the data nodes to fail. The issue was observed when using extent sizes of 100 MB and larger. (Bug #39096) * *Disk Data*: Creation of a tablespace data file whose size was greater than 4 GB failed silently on 32-bit platforms. (Bug #37116) See also Bug #29186. * *Disk Data*: `O_SYNC' was incorrectly disabled on platforms that do not support `O_DIRECT'. This issue was noted on Solaris but could have affected other platforms not having `O_DIRECT' capability. (Bug #34638) * *Disk Data*: Trying to execute a *Note `CREATE LOGFILE GROUP': create-logfile-group. statement using a value greater than `150M' for `UNDO_BUFFER_SIZE' caused data nodes to crash. As a result of this fix, the upper limit for `UNDO_BUFFER_SIZE' is now `600M'; attempting to set a higher value now fails gracefully with an error. (Bug #34102) See also Bug #36702. * *Disk Data*: When attempting to create a tablespace that already existed, the error message returned was `Table or index with given name already exists'. (Bug #32662) * *Disk Data*: Using a path or filename longer than 128 characters for Disk Data undo log files and tablespace data files caused a number of issues, including failures of *Note `CREATE LOGFILE GROUP': create-logfile-group, *Note `ALTER LOGFILE GROUP': alter-logfile-group, *Note `CREATE TABLESPACE': create-tablespace, and *Note `ALTER TABLESPACE': alter-tablespace. statements, as well as crashes of management nodes and data nodes. With this fix, the maximum length for path and file names used for Disk Data undo log files and tablespace data files is now the same as the maximum for the operating system. (Bug #31769, Bug #31770, Bug #31772) * *Disk Data*: Starting a cluster under load such that Disk Data tables used most of the undo buffer could cause data node failures. The fix for this bug also corrected an issue in the `LGMAN' kernel block where the amount of free space left in the undo buffer was miscalculated, causing buffer overruns. This could cause records in the buffer to be overwritten, leading to problems when restarting data nodes. (Bug #28077) * *Disk Data*: Attempting to perform a system restart of the cluster where there existed a logfile group without and undo log files caused the data nodes to crash. *Note*: While issuing a *Note `CREATE LOGFILE GROUP': create-logfile-group. statement without an `ADD UNDOFILE' option fails with an error in the MySQL server, this situation could arise if an SQL node failed during the execution of a valid *Note `CREATE LOGFILE GROUP': create-logfile-group. statement; it is also possible to create a logfile group without any undo log files using the NDB API. (Bug #17614) * *Cluster Replication*: Sometimes, when using the `--ndb_log_orig' option, the `orig_epoch' and `orig_server_id' columns of the `ndb_binlog_index' table on the slave contained the ID and epoch of the local server instead. (Bug #41601) * *Cluster API*: Some error messages from *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. contained newline (`\n') characters. This could break the MGM API protocol, which uses the newline as a line separator. (Bug #43104) * *Cluster API*: When using an ordered index scan without putting all key columns in the read mask, this invalid use of the NDB API went undetected, which resulted in the use of uninitialized memory. (Bug #42591) * *Cluster API*: The MGM API reset error codes on management server handles before checking them. This meant that calling an MGM API function with a null handle caused applications to crash. (Bug #40455) * *Cluster API*: It was not always possible to access parent objects directly from `NdbBlob', `NdbOperation', and `NdbScanOperation' objects. To alleviate this problem, a new `getNdbOperation()' method has been added to `NdbBlob' and new getNdbTransaction() methods have been added to `NdbOperation' and `NdbScanOperation'. In addition, a const variant of `NdbOperation::getErrorLine()' is now also available. (Bug #40242) * *Cluster API*: `NdbScanOperation::getBlobHandle()' failed when used with incorrect column names or numbers. (Bug #40241) * *Cluster API*: The NDB API example programs included in MySQL Cluster source distributions failed to compile. (Bug #37491) See also Bug #40238. * *Cluster API*: `mgmapi.h' contained constructs which only worked in C++, but not in C. (Bug #27004)  File: manual.info, Node: mysql-cluster-news-5-1-28-ndb-6-2-16, Next: mysql-cluster-news-5-1-23-ndb-6-2-15, Prev: mysql-cluster-news-5-1-32-ndb-6-2-17, Up: mysql-cluster-news-6-2 17.7.5.4 Changes in MySQL Cluster NDB 6.2.16 (5.1.28-ndb-6.2.16) (08 October 2008) .................................................................................. This is a bugfix release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.2 release. Obtaining MySQL Cluster NDB 6.2 You can download the latest MySQL Cluster NDB 6.2 source code and binaries for supported platforms from ftp://ftp.mysql.com/pub/mysql/download/cluster_telco/mysql-5.1.28-ndb-6.2.16. This release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.2 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.28 (see *Note news-5-1-28::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * It is no longer a requirement for database autodiscovery that an SQL node already be connected to the cluster at the time that a database is created on another SQL node. It is no longer necessary to issue *Note `CREATE DATABASE': create-database. (or *Note `CREATE SCHEMA': create-database.) statements on an SQL node joining the cluster after a database is created for the new SQL node to see the database and any `NDCLUSTER' tables that it contains. (Bug #39612) *Bugs fixed:* * Heavy DDL usage caused the *Note `mysqld': mysqld. processes to hang due to a timeout error (*Note `NDB': mysql-cluster. error code 266). (Bug #39885) * Executing *Note `EXPLAIN SELECT': explain. on an *Note `NDBCLUSTER': mysql-cluster. table could cause *Note `mysqld': mysqld. to crash. (Bug #39872) * Starting the MySQL Server with the `--ndbcluster' option plus an invalid command-line option (for example, using *Note `mysqld': mysqld. `--ndbcluster --foobar') caused it to hang while shutting down the binlog thread. (Bug #39635) * Dropping and then re-creating a database on one SQL node caused other SQL nodes to hang. (Bug #39613) * Setting a low value of `MaxNoOfLocalScans' (< 100) and performing a large number of (certain) scans could cause the Transaction Coordinator to run out of scan fragment records, and then crash. Now when this resource is exhausted, the cluster returns Error 291 (`Out of scanfrag records in TC (increase MaxNoOfLocalScans)') instead. (Bug #39549) * Creating a unique index on an *Note `NDBCLUSTER': mysql-cluster. table caused a memory leak in the *Note `NDB': mysql-cluster. subscription manager (`SUMA') which could lead to mysqld hanging, due to the fact that the resource shortage was not reported back to the *Note `NDB': mysql-cluster. kernel correctly. (Bug #39518) See also Bug #39450. * Unique identifiers in tables having no primary key were not cached. This fix has been observed to increase the efficiency of *Note `INSERT': insert. operations on such tables by as much as 50%. (Bug #39267) * `MgmtSrvr::allocNodeId()' left a mutex locked following an `Ambiguity for node if %d' error. (Bug #39158) * An invalid path specification caused `mysql-test-run.pl' to fail. (Bug #39026) * During transactional coordinator takeover (directly after node failure), the LQH finding an operation in the `LOG_COMMIT' state sent an `LQH_TRANS_CONF' signal twice, causing the TC to fail. (Bug #38930) * An invalid memory access caused the management server to crash on Solaris Sparc platforms. (Bug #38628) * A segfault in `Logger::Log' caused *Note `ndbd': mysql-cluster-programs-ndbd. to hang indefinitely. (Bug #38609) * *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. failed to start on older Linux distributions (2.4 kernels) that did not support e-polling. (Bug #38592) * When restarting a data node, an excessively long shutodwn message could cause the node process to crash. (Bug #38580) * *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. sometimes performed unnecessary network I/O with the client. This in combination with other factors led to long-running threads that were attempting to write to clients that no longer existed. (Bug #38563) * *Note `ndb_restore': mysql-cluster-programs-ndb-restore. failed with a floating point exception due to a division by zero error when trying to restore certain data files. (Bug #38520) * A failed connection to the management server could cause a resource leak in *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. (Bug #38424) * Failure to parse configuration parameters could cause a memory leak in the NDB log parser. (Bug #38380) * After a forced shutdown and initial restart of the cluster, it was possible for SQL nodes to retain `.frm' files corresponding to *Note `NDBCLUSTER': mysql-cluster. tables that had been dropped, and thus to be unaware that these tables no longer existed. In such cases, attempting to re-create the tables using `CREATE TABLE IF NOT EXISTS' could fail with a spurious `Table ... doesn't exist' error. (Bug #37921) * Renaming an *Note `NDBCLUSTER': mysql-cluster. table on one SQL node, caused a trigger on this table to be deleted on another SQL node. (Bug #36658) * Attempting to add a `UNIQUE INDEX' twice to an *Note `NDBCLUSTER': mysql-cluster. table, then deleting rows from the table could cause the MySQL Server to crash. (Bug #35599) * *Note `ndb_restore': mysql-cluster-programs-ndb-restore. failed when a single table was specified. (Bug #33801) * `GCP_COMMIT' did not wait for transaction takeover during node failure. This could cause `GCP_SAVE_REQ' to be executed too early. This could also cause (very rarely) replication to skip rows. (Bug #30780) * *Cluster Replication*: In some cases, dropping a database on the master could cause table logging to fail on the slave, or, when using a debug build, could cause the slave *Note `mysqld': mysqld. to fail completely. (Bug #39404) * *Cluster Replication*: During a parallel node restart, the starting nodes could (sometimes) incorrectly synchronize subscriptions among themselves. Instead, this synchronization now takes place only among nodes that have actually (completely) started. (Bug #38767) * *Cluster Replication*: Data was written to the binlog with `--log-slave-updates' disabled. (Bug #37472) * *Cluster API*: Passing a value greater than 65535 to `NdbInterpretedCode::add_val()' and `NdbInterpretedCode::sub_val()' caused these methods to have no effect. (Bug #39536) * *Cluster API*: The `NdbScanOperation::readTuples()' method could be called multiple times without error. (Bug #38717) * *Cluster API*: Certain Multi-Range Read scans involving `IS NULL' and `IS NOT NULL' comparisons failed with an error in the *Note `NDB': mysql-cluster. local query handler. (Bug #38204) * *Cluster API*: Problems with the public headers prevented *Note `NDB': mysql-cluster. applications from being built with warnings turned on. (Bug #38177) * *Cluster API*: Creating an `NdbScanFilter' object using an `NdbScanOperation' object that had not yet had its `readTuples()' method called resulted in a crash when later attempting to use the `NdbScanFilter'. (Bug #37986) * *Cluster API*: Executing an `NdbRecord' interpreted delete created with an `ANYVALUE' option caused the transaction to abort. (Bug #37672) * *Cluster API*: Accesing the debug version of `libndbclient' using `dlopen()' resulted in a segmentation fault. (Bug #35927)  File: manual.info, Node: mysql-cluster-news-5-1-23-ndb-6-2-15, Next: mysql-cluster-news-5-1-23-ndb-6-2-14, Prev: mysql-cluster-news-5-1-28-ndb-6-2-16, Up: mysql-cluster-news-6-2 17.7.5.5 Changes in MySQL Cluster NDB 6.2.15 (5.1.23-ndb-6.2.15) (22 May 2008) .............................................................................. This is re-release of MySQL Cluster NDB 6.2.14 providing binaries for supported platforms. For more information, see *Note mysql-cluster-news-5-1-23-ndb-6-2-14::. Obtaining MySQL Cluster NDB 6.2 You can download the latest MySQL Cluster NDB 6.2 source code and binaries for supported platforms from http://dev.mysql.com/downloads/cluster/.  File: manual.info, Node: mysql-cluster-news-5-1-23-ndb-6-2-14, Next: mysql-cluster-news-5-1-23-ndb-6-2-13, Prev: mysql-cluster-news-5-1-23-ndb-6-2-15, Up: mysql-cluster-news-6-2 17.7.5.6 Changes in MySQL Cluster NDB 6.2.14 (5.1.23-ndb-6.2.14) (05 March 2008) ................................................................................ This is a bugfix release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.2 release. Obtaining MySQL Cluster NDB 6.2 You can download the latest MySQL Cluster NDB 6.2 source code and binaries for supported platforms from http://dev.mysql.com/downloads/cluster/. This release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.2 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.23 (see *Note news-5-1-23::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * Added the `MaxBufferedEpochs' data node configuration parameter, which controls the maximum number of unprocessed epochs by which a subscribing node can lag. Subscribers which exceed this number are disconnected and forced to reconnect. See *Note mysql-cluster-ndbd-definition::, for more information. * *Replication*: Introduced the `slave_exec_mode' system variable to control whether idempotent or strict mode is used for replication conflict resolution. Idempotent mode suppresses duplicate-key, no-key-found, and some other errors, and is needed for circular replication, multi-master replication, and some other complex replication setups when using MySQL Cluster, where idempotent mode is the default. However, strict mode is the default for storage engines other than *Note `NDB': mysql-cluster. (Bug #31609) * *Cluster Replication*: *Note `RESET MASTER': reset-master. now uses *Note `TRUNCATE TABLE': truncate-table. rather than *Note `DELETE': delete. to clear the `mysql.ndb_binlog_index' table. This improves the performance of the statement and is less likely to leave the table in a fragmented state. (Bug #34356) * Formerly, when the MySQL server crashed, the generated stack dump was numeric and required external tools to properly resolve the names of functions. This is not very helpful to users having a limited knowledge of debugging techniques. In addition, the generated stack trace contained only the names of functions and was formatted differently for each platform due to different stack layouts. Now it is possible to take advantage of newer versions of the GNU C Library provide a set of functions to obtain and manipulate stack traces from within the program. On systems that use the ELF binary format, the stack trace contains important information such as the shared object where the call was generated, an offset into the function, and the actual return address. Having the function name also makes possible the name demangling of C++ functions. The library generates meaningful stack traces on the following platforms: i386, x86_64, PowerPC, IA64, Alpha, and S390. On other platforms, a numeric stack trace is still produced, and the use of the *Note `resolve_stack_dump': resolve-stack-dump. utility is still required. (Bug #31891) * `mysqltest' now has `mkdir' and `rmdir' commands for creating and removing directories. (Bug #31004) * Added the `Uptime_since_flush_status' status variable, which indicates the number of seconds since the most recent `FLUSH STATUS' statement. (Community contribution by Jeremy Cole) (Bug #24822) *Bugs fixed:* * *Performance*: `InnoDB' exhibited thread thrashing with more than 50 concurrent connections under an update-intensive workload. (Bug #22868) * *Incompatible Change*: The *Note `UPDATE': update. statement permitted `NULL' to be assigned to `NOT NULL' columns (the implicit default value for the column data type was assigned). This was changed so that on error occurs. This change was reverted, because the original report was determined not to be a bug: Assigning `NULL' to a `NOT NULL' column in an *Note `UPDATE': update. statement should produce an error only in strict SQL mode and set the column to the implicit default with a warning otherwise, which was the original behavior. See *Note data-type-defaults::, and Bug#39265. (Bug #33699) * *Important Change*: *Replication*: When the master crashed during an update on a transactional table while in `autocommit' mode, the slave failed. This fix causes every transaction (including `autocommit' transactions) to be recorded in the binary log as starting with a *Note `BEGIN': commit. and ending with a *Note `COMMIT': commit. or *Note `ROLLBACK': commit. *Note*: The current fix does _not_ cause nontransactional changes to be wrapped in *Note `BEGIN': commit ... *Note `COMMIT': commit. or *Note `BEGIN': commit ... *Note `ROLLBACK': commit. when written to the binary log. For this purpose, any statements affecting tables using a nontransactional storage engine such as *Note `MyISAM': myisam-storage-engine. are regarded as nontransactional, even when `autocommit' is enabled. (Bug #26395) See also Bug #29288, Bug #49522. * *Replication*: *Important Note*: Network timeouts between the master and the slave could result in corruption of the relay log. This fix rectifies a long-standing replication issue when using unreliable networks, including replication over wide area networks such as the Internet. If you experience reliability issues and see many `You have an error in your SQL syntax' errors on replication slaves, we strongly recommend that you upgrade to a MySQL version which includes this fix. (Bug #26489) * *Replication*: When the Windows version of *Note `mysqlbinlog': mysqlbinlog. read 4.1 binlogs containing *Note `LOAD DATA INFILE': load-data. statements, it output backslashes as path separators, causing problems for client programs expecting forward slashes. In such cases, it now converts `\\' to `/' in directory paths. (Bug #34355) * *Replication*: *Note `SHOW SLAVE STATUS': show-slave-status. failed when slave I/O was about to terminate. (Bug #34305) * *Replication*: *Note `mysqlbinlog': mysqlbinlog. from a 5.1 or later MySQL distribution could not read binary logs generated by a 4.1 server when the logs contained *Note `LOAD DATA INFILE': load-data. statements. (Bug #34141) This regression was introduced by Bug #32407. * *Replication*: A *Note `CREATE USER': create-user, *Note `DROP USER': drop-user, or *Note `RENAME USER': rename-user. statement that fails on the master, or that is a duplicate of any of these statements, is no longer written to the binlog; previously, either of these occurrences could cause the slave to fail. (Bug #33862) See also Bug #29749. * *Replication*: *Note `mysqlbinlog': mysqlbinlog. failed to release all of its memory after terminating abnormally. (Bug #33247) * *Replication*: The error message generated due to lack of a default value for an extra column was not sufficiently informative. (Bug #32971) * *Replication*: When a user variable was used inside an *Note `INSERT': insert. statement, the corresponding binlog event was not written to the binlog correctly. (Bug #32580) * *Replication*: When using row-based replication, deletes from a table with a foreign key constraint failed on the slave. (Bug #32468) * *Replication*: SQL statements containing comments using `--' syntax were not replayable by *Note `mysqlbinlog': mysqlbinlog, even though such statements replicated correctly. (Bug #32205) * *Replication*: When using row-based replication from a master running MySQL 5.1.21 or earlier to a slave running 5.1.22 or later, updates of integer columns failed on the slave with `Error in Unknown event: row application failed'. (Bug #31583) This regression was introduced by Bug #21842. * *Replication*: Replicating write, update, or delete events from a master running MySQL 5.1.15 or earlier to a slave running 5.1.16 or later caused the slave to crash. (Bug #31581) * *Replication*: When using row-based replication, the slave stopped when attempting to delete nonexistent rows from a slave table without a primary key. In addition, no error was reported when this occurred. (Bug #31552) * *Replication*: Issuing a *Note `DROP VIEW': drop-view. statement caused replication to fail if the view did not actually exist. (Bug #30998) * *Replication*: Replication of *Note `LOAD DATA INFILE': load-data. could fail when `read_buffer_size' was larger than `max_allowed_packet'. (Bug #30435) * *Replication*: Replication crashed with the *Note `NDB': mysql-cluster. storage engine when *Note `mysqld': mysqld. was started with `--character-set-server=ucs2'. (Bug #29562) * *Replication*: Setting `server_id' did not update its value for the current session. (Bug #28908) * *Replication*: Some older servers wrote events to the binary log using different numbering from what is currently used, even though the file format number in the file is the same. Slaves running MySQL 5.1.18 and later could not read these binary logs properly. Binary logs from these older versions now are recognized and event numbers are mapped to the current numbering so that they can be interpreted properly. (Bug #27779, Bug #32434) This regression was introduced by Bug #22583. * *Cluster Replication*: Using `--ndb-wait-connected' caused the server to wait for a partial connection, plus an additional 3 seconds for a complete connection to the cluster. This could lead to issues with setting up the binary log. (Bug #34757) * *Cluster API*: Closing a scan before it was executed caused the application to segfault. (Bug #36375) * *Cluster API*: Using NDB API applications from older MySQL Cluster versions with `libndbclient' from newer ones caused the cluster to fail. (Bug #36124) * *Cluster API*: Scans having no bounds set were handled incorrectly. (Bug #35876) * Use of stored functions in the `WHERE' clause for *Note `SHOW OPEN TABLES': show-open-tables. caused a server crash. (Bug #34166) * Large unsigned integers were improperly handled for prepared statements, resulting in truncation or conversion to negative numbers. (Bug #33798) * The server crashed when executing a query that had a subquery containing an equality X=Y where Y referred to a named select list expression from the parent select. The server crashed when trying to use the X=Y equality for `ref'-based access. (Bug #33794) * `ORDER BY ... DESC' sorts could produce misordered results. (Bug #33697) * The server could crash when *Note `REPEAT': repeat-statement. or another control instruction was used in conjunction with labels and a *Note `LEAVE': leave-statement. instruction. (Bug #33618) * `SET GLOBAL myisam_max_sort_file_size=DEFAULT' set `myisam_max_sort_file_size' to an incorrect value. (Bug #33382) See also Bug #31177. * Granting the `UPDATE' privilege on one column of a view caused the server to crash. (Bug #33201) * For *Note `DECIMAL': numeric-types. columns used with the `ROUND(X,D)' or `TRUNCATE(X,D)' function with a nonconstant value of D, adding an `ORDER BY' for the function result produced misordered output. (Bug #33143) See also Bug #33402, Bug #30617. * The *Note `SHOW ENGINE INNODB STATUS': show-engine. and *Note `SHOW ENGINE INNODB MUTEX': show-engine. statements incorrectly required the `SUPER' privilege rather than the `PROCESS' privilege. (Bug #32710) * Tables in the `mysql' database that stored the current `sql_mode' value as part of stored program definitions were not updated with newer mode values (`NO_ENGINE_SUBSTITUTION', `PAD_CHAR_TO_FULL_LENGTH'). This causes various problems defining stored programs if those modes were included in the current `sql_mode' value. (Bug #32633) * `ROUND(X,D)' or `TRUNCATE(X,D)' for nonconstant values of D could crash the server if these functions were used in an `ORDER BY' that was resolved using `filesort'. (Bug #30889) * Resetting the query cache by issuing a `SET GLOBAL query_cache_size=0' statement caused the server to crash if it concurrently was saving a new result set to the query cache. (Bug #30887) * The `Table_locks_waited' waited variable was not incremented in the cases that a lock had to be waited for but the waiting thread was killed or the request was aborted. (Bug #30331) * The `Com_create_function' status variable was not incremented properly. (Bug #30252) * *Note `mysqld': mysqld. displayed the `--enable-pstack' option in its help message even if MySQL was configured without `--with-pstack'. (Bug #29836) * Views were treated as insertable even if some base table columns with no default value were omitted from the view definition. (This is contrary to the condition for insertability that a view must contain all columns in the base table that do not have a default value.) (Bug #29477) * Previously, the parser accepted the ODBC `{ OJ ... LEFT OUTER JOIN ...}' syntax for writing left outer joins. The parser now permits `{ OJ ... }' to be used to write other types of joins, such as `INNER JOIN' or `RIGHT OUTER JOIN'. This helps with compatibility with some third-party applications, but is not official ODBC syntax. (Bug #28317) * The parser rules for the *Note `SHOW PROFILE': show-profile. statement were revised to work with older versions of `bison'. (Bug #27433) * *Note `resolveip': resolveip. failed to produce correct results for host names that begin with a digit. (Bug #27427) * *Note `mysqlcheck -A -r': mysqlcheck. did not correctly identify all tables that needed repairing. (Bug #25347) * Warnings for deprecated syntax constructs used in stored routines make sense to report only when the routine is being created, but they were also being reported when the routine was parsed for loading into the execution cache. Now they are reported only at routine creation time. (Bug #21801) * `CREATE ... SELECT' did not always set `DEFAULT' column values in the new table. (Bug #21380) * If a *Note `SELECT': select. calls a stored function in a transaction, and a statement within the function fails, that statement should roll back. Furthermore, if *Note `ROLLBACK': commit. is executed after that, the entire transaction should be rolled back. Before this fix, the failed statement did not roll back when it failed (even though it might ultimately get rolled back by a *Note `ROLLBACK': commit. later that rolls back the entire transaction). (Bug #12713) See also Bug #34655.  File: manual.info, Node: mysql-cluster-news-5-1-23-ndb-6-2-13, Next: mysql-cluster-news-5-1-23-ndb-6-2-12, Prev: mysql-cluster-news-5-1-23-ndb-6-2-14, Up: mysql-cluster-news-6-2 17.7.5.7 Changes in MySQL Cluster NDB 6.2.13 (5.1.23-ndb-6.2.13) (22 February 2008) ................................................................................... This is a bugfix release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.2 release. Obtaining MySQL Cluster NDB 6.2 You can download the latest MySQL Cluster NDB 6.2 source code and binaries for supported platforms from http://dev.mysql.com/downloads/cluster/. This release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.2 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.23 (see *Note news-5-1-23::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Bugs fixed:* * A node failure during an initial node restart followed by another node start could cause the master data node to fail, because it incorrectly gave the node permission to start even if the invalidated node's LCP was still running. (Bug #34702)  File: manual.info, Node: mysql-cluster-news-5-1-23-ndb-6-2-12, Next: mysql-cluster-news-5-1-23-ndb-6-2-11, Prev: mysql-cluster-news-5-1-23-ndb-6-2-13, Up: mysql-cluster-news-6-2 17.7.5.8 Changes in MySQL Cluster NDB 6.2.12 (5.1.23-ndb-6.2.12) (12 February 2008) ................................................................................... This is a bugfix release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.2 release. Obtaining MySQL Cluster NDB 6.2 You can download the latest MySQL Cluster NDB 6.2 source code and binaries for supported platforms from http://dev.mysql.com/downloads/cluster/. This release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.2 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.23 (see *Note news-5-1-23::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * Beginning with this version, MySQL Cluster NDB 6.3.X releases once again include the `InnoDB' storage engine. To enable `InnoDB', you must configure the build using `--with-innodb'. *Bugs fixed:* * Upgrades of a cluster using while a `DataMemory' setting in excess of 16 GB caused data nodes to fail. (Bug #34378) * Performing many SQL statements on *Note `NDB': mysql-cluster. tables while in `autocommit' mode caused a memory leak in *Note `mysqld': mysqld. (Bug #34275) * In certain rare circumstances, a race condition could occur between an aborted insert and a delete leading a data node crash. (Bug #34260) * Multi-table updates using ordered indexes during handling of node failures could cause other data nodes to fail. (Bug #34216) * When configured with *Note `NDB': mysql-cluster. support, MySQL failed to compile using `gcc' 4.3 on 64bit FreeBSD systems. (Bug #34169) * The failure of a DDL statement could sometimes lead to node failures when attempting to execute subsequent DDL statements. (Bug #34160) * Extremely long *Note `SELECT': select. statements (where the text of the statement was in excess of 50000 characters) against *Note `NDB': mysql-cluster. tables returned empty results. (Bug #34107) * Statements executing multiple inserts performed poorly on *Note `NDB': mysql-cluster. tables having `AUTO_INCREMENT' columns. (Bug #33534) * The *Note `ndb_waiter': mysql-cluster-programs-ndb-waiter. utility polled *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. excessively when obtaining the status of cluster data nodes. (Bug #32025) See also Bug #32023. * Transaction atomicity was sometimes not preserved between reads and inserts under high loads. (Bug #31477) * Having tables with a great many columns could cause Cluster backups to fail. (Bug #30172) * *Cluster Replication*: *Disk Data*: Statements violating unique keys on Disk Data tables (such as attempting to insert `NULL' into a `NOT NULL' column) could cause data nodes to fail. When the statement was executed from the binlog, this could also result in failure of the slave cluster. (Bug #34118) * *Disk Data*: Updating in-memory columns of one or more rows of Disk Data table, followed by deletion of these rows and re-insertion of them, caused data node failures. (Bug #33619) * *Cluster Replication*: Setting `--replicate-ignore-db=mysql' caused the `mysql.ndb_apply_status' table not to be replicated, breaking Cluster Replication. (Bug #28170)  File: manual.info, Node: mysql-cluster-news-5-1-23-ndb-6-2-11, Next: mysql-cluster-news-5-1-23-ndb-6-2-10, Prev: mysql-cluster-news-5-1-23-ndb-6-2-12, Up: mysql-cluster-news-6-2 17.7.5.9 Changes in MySQL Cluster NDB 6.2.11 (5.1.23-ndb-6.2.11) (28 January 2008) .................................................................................. This is a bugfix release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.2 release. Obtaining MySQL Cluster NDB 6.2 You can download the latest MySQL Cluster NDB 6.2 source code and binaries for supported platforms from http://dev.mysql.com/downloads/cluster/. This release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.2 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.23 (see *Note news-5-1-23::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * *Cluster API*: *Important Change*: Because `NDB_LE_MemoryUsage.page_size_kb' shows memory page sizes in bytes rather than kilobytes, it has been renamed to `page_size_bytes'. The name `page_size_kb' is now deprecated and thus subject to removal in a future release, although it currently remains supported for reasons of backward compatibility. See The `Ndb_logevent_type' Type (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-logevent-type.html), for more information about `NDB_LE_MemoryUsage'. (Bug #30271) *Bugs fixed:* * High numbers of insert operations, delete operations, or both could cause *Note `NDB': mysql-cluster. error 899 (`Rowid already allocated') to occur unnecessarily. (Bug #34033) * A periodic failure to flush the send buffer by the *Note `NDB': mysql-cluster. TCP transporter could cause a unnecessary delay of 10 ms between operations. (Bug #34005) * A race condition could occur (very rarely) when the release of a GCI was followed by a data node failure. (Bug #33793) * Some tuple scans caused the wrong memory page to be accessed, leading to invalid results. This issue could affect both in-memory and Disk Data tables. (Bug #33739) * The server failed to reject properly the creation of an *Note `NDB': mysql-cluster. table having an unindexed `AUTO_INCREMENT' column. (Bug #30417) * Issuing an *Note `INSERT ... ON DUPLICATE KEY UPDATE': insert-on-duplicate. concurrently with or following a *Note `TRUNCATE TABLE': truncate-table. statement on an *Note `NDB': mysql-cluster. table failed with *Note `NDB': mysql-cluster. error 4350 `Transaction already aborted'. (Bug #29851) * The Cluster backup process could not detect when there was no more disk space and instead continued to run until killed manually. Now the backup fails with an appropriate error when disk space is exhausted. (Bug #28647) * It was possible in `config.ini' to define cluster nodes having node IDs greater than the maximum permitted value. (Bug #28298) * *Cluster Replication*: *Note `ndb_restore -e': mysql-cluster-programs-ndb-restore. restored excessively large values to the `ndb_apply_status' table's `epoch' column when restoring to a MySQL Cluster version supporting Micro-GCPs from an older version that did not support these. A workaround when restoring to MySQL Cluster releases supporting micro-GCPs previous to MySQL Cluster NDB 6.3.8 is to perform a 32-bit shift on the `epoch' column values to reduce them to their proper size. (Bug #33406) * *Cluster API*: Transactions containing inserts or reads would hang during `NdbTransaction::execute()' calls made from NDB API applications built against a MySQL Cluster version that did not support micro-GCPs accessing a later version that supported micro-GCPs. This issue was observed while upgrading from MySQL Cluster NDB 6.1.23 to MySQL Cluster NDB 6.2.10 when the API application built against the earlier version attempted to access a data node already running the later version, even after disabling micro-GCPs by setting `TimeBetweenEpochs' equal to 0. (Bug #33895) * *Cluster API*: When reading a `BIT(64)' value using `NdbOperation:getValue()', 12 bytes were written to the buffer rather than the expected 8 bytes. (Bug #33750)  File: manual.info, Node: mysql-cluster-news-5-1-23-ndb-6-2-10, Next: mysql-cluster-news-5-1-22-ndb-6-2-9, Prev: mysql-cluster-news-5-1-23-ndb-6-2-11, Up: mysql-cluster-news-6-2 17.7.5.10 Changes in MySQL Cluster NDB 6.2.10 (5.1.23-ndb-6.2.10) (19 December 2007) .................................................................................... This is a bugfix release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.2 release. Obtaining MySQL Cluster NDB 6.2 You can download the latest MySQL Cluster NDB 6.2 source code and binaries for supported platforms from http://dev.mysql.com/downloads/cluster/. This Beta release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.2 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.23 (see *Note news-5-1-23::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Bugs fixed:* * *Partitioning*: When partition pruning on an *Note `NDB': mysql-cluster. table resulted in an ordered index scan spanning only one partition, any descending flag for the scan was wrongly discarded, causing `ORDER BY DESC' to be treated as `ORDER BY ASC', `MAX()' to be handled incorrectly, and similar problems. (Bug #33061) * When all data and SQL nodes in the cluster were shut down abnormally (that is, other than by using `STOP' in the cluster management client), *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. used excessive amounts of CPU. (Bug #33237) * When using micro-GCPs, if a node failed while preparing for a global checkpoint, the master node would use the wrong GCI. (Bug #32922) * Under some conditions, performing an *Note `ALTER TABLE': alter-table. on an *Note `NDBCLUSTER': mysql-cluster. table failed with a `Table is full' error, even when only 25% of `DataMemory' was in use and the result should have been a table using less memory (for example, changing a `VARCHAR(100)' column to `VARCHAR(80)'). (Bug #32670)  File: manual.info, Node: mysql-cluster-news-5-1-22-ndb-6-2-9, Next: mysql-cluster-news-5-1-22-ndb-6-2-8, Prev: mysql-cluster-news-5-1-23-ndb-6-2-10, Up: mysql-cluster-news-6-2 17.7.5.11 Changes in MySQL Cluster NDB 6.2.9 (5.1.22-ndb-6.2.9) (22 November 2007) .................................................................................. This is a bugfix release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.2 release. Obtaining MySQL Cluster NDB 6.2 You can download the latest MySQL Cluster NDB 6.2 source code and binaries for supported platforms from http://dev.mysql.com/downloads/cluster/. This Beta release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.2 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.22 (see *Note news-5-1-22::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * Added the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client command `DUMP 8011', which dumps all subscribers to the cluster log. See `DUMP 8011' (http://dev.mysql.com/doc/ndbapi/en/ndb-internals-dump-command-8011.html), for more information. *Bugs fixed:* * A local checkpoint could sometimes be started before the previous LCP was restorable from a global checkpoint. (Bug #32519) * High numbers of API nodes on a slow or congested network could cause connection negotiation to time out prematurely, leading to the following issues: * Excessive retries * Excessive CPU usage * Partially connected API nodes (Bug #32359) * The failure of a master node could lead to subsequent failures in local checkpointing. (Bug #32160) * Adding a new *Note `TINYTEXT': blob. column to an *Note `NDB': mysql-cluster. table which used `COLUMN_FORMAT = DYNAMIC', and when binary logging was enabled, caused all cluster *Note `mysqld': mysqld. processes to crash. (Bug #30213) * After adding a new column of one of the *Note `TEXT': blob. or *Note `BLOB': blob. types to an *Note `NDB': mysql-cluster. table which used `COLUMN_FORMAT = DYNAMIC', it was no longer possible to access or drop the table using SQL. (Bug #30205) * A restart of the cluster failed when more than 1 REDO phase was in use. (Bug #22696) * *Cluster Replication*: *Replication*: Where a table being replicated had a *Note `TEXT': blob. or *Note `BLOB': blob. column, an *Note `UPDATE': update. on the master that did not refer explicitly to this column in the `WHERE' clause stopped the SQL thread on the slave with `Error in Write_rows event: row application failed. Got error 4288 'Blob handle for column not available' from NDBCLUSTER'. (Bug #30674) * *Cluster Replication*: Under certain conditions, the slave stopped processing relay logs. This resulted in the logs never being cleared and the slave eventually running out of disk space. (Bug #31958)  File: manual.info, Node: mysql-cluster-news-5-1-22-ndb-6-2-8, Next: mysql-cluster-news-5-1-22-ndb-6-2-7, Prev: mysql-cluster-news-5-1-22-ndb-6-2-9, Up: mysql-cluster-news-6-2 17.7.5.12 Changes in MySQL Cluster NDB 6.2.8 (5.1.22-ndb-6.2.8) (08 November 2007) .................................................................................. This is a bugfix release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.2 release. Obtaining MySQL Cluster NDB 6.2 You can download the latest MySQL Cluster NDB 6.2 source code and binaries for supported platforms from http://dev.mysql.com/downloads/cluster/. This Beta release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.2 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.22 (see *Note news-5-1-22::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * *Important Note*: MySQL Cluster NDB 6.2 and 6.3 source archives are now available in separate commercial and GPL versions. Due to licensing concerns, previous MySQL Cluster NDB 6.2 and 6.3 source archives were removed from the FTP site. * The output of the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client `SHOW' and `STATUS' commands now indicates when the cluster is in single user mode. (Bug #27999) *Bugs fixed:* * In a cluster running in diskless mode and with arbitration disabled, the failure of a data node during an insert operation caused other data node to fail. (Bug #31980) * An insert or update with combined range and equality constraints failed when run against an *Note `NDB': mysql-cluster. table with the error `Got unknown error from NDB'. An example of such a statement would be `UPDATE t1 SET b = 5 WHERE a IN (7,8) OR a >= 10;'. (Bug #31874) * An error with an `if' statement in `sql/ha_ndbcluster.cc' could potentially lead to an infinite loop in case of failure when working with `AUTO_INCREMENT' columns in *Note `NDB': mysql-cluster. tables. (Bug #31810) * The *Note `NDB': mysql-cluster. storage engine code was not safe for strict-alias optimization in `gcc' 4.2.1. (Bug #31761) * Following an upgrade, *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. would fail with an ArbitrationError. (Bug #31690) * The *Note `NDB': mysql-cluster. management client command `NODE_ID REPORT MEMORY' provided no output when NODE_ID was the node ID of a management or API node. Now, when this occurs, the management client responds with `Node NODE_ID: is not a data node'. (Bug #29485) * Performing *Note `DELETE': delete. operations after a data node had been shut down could lead to inconsistent data following a restart of the node. (Bug #26450) * `UPDATE IGNORE' could sometimes fail on *Note `NDB': mysql-cluster. tables due to the use of unitialized data when checking for duplicate keys to be ignored. (Bug #25817) * *Cluster Replication*: *Replication*: A node failure during replication could lead to buckets out of order; now active subscribers are checked for, rather than empty buckets. (Bug #31701) * *Cluster Replication*: When the master *Note `mysqld': mysqld. crashed or was restarted, no `LOST_EVENTS' entry was made in the binlog. (Bug #31484) See also Bug #21494.  File: manual.info, Node: mysql-cluster-news-5-1-22-ndb-6-2-7, Next: mysql-cluster-news-5-1-22-ndb-6-2-6, Prev: mysql-cluster-news-5-1-22-ndb-6-2-8, Up: mysql-cluster-news-6-2 17.7.5.13 Changes in MySQL Cluster NDB 6.2.7 (5.1.22-ndb-6.2.7) (10 October 2007) ................................................................................. This is a bugfix release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.2 release. Obtaining MySQL Cluster NDB 6.2 You can download the latest MySQL Cluster NDB 6.2 source code and binaries for supported platforms from http://dev.mysql.com/downloads/cluster/. This Beta release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.2 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.22 (see *Note news-5-1-22::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * *Cluster Replication*: A new configuration parameter `TimeBetweenEpochsTimeout' enables a timeout to be set for time between epochs. (Bug #31276) * Additional checks were implemented to catch unsupported online *Note `ALTER TABLE': alter-table. operations. Currently it is not possible to reorder columns or to change the storage engine used for a table using online *Note `ALTER TABLE': alter-table. Some redundant checks made during online creation of indexes were removed. *Bugs fixed:* * It was possible in some cases for a node group to be `lost' due to missed local checkpoints following a system restart. (Bug #31525) * *Note `NDB': mysql-cluster. tables having names containing nonalphanumeric characters (such as ``$'') were not discovered correctly. (Bug #31470) * A node failure during a local checkpoint could lead to a subsequent failure of the cluster during a system restart. (Bug #31257) * A cluster restart could sometimes fail due to an issue with table IDs. (Bug #30975) * Transaction timeouts were not handled well in some circumstances, leading to excessive number of transactions being aborted unnecessarily. (Bug #30379) * In some cases, the cluster managment server logged entries multiple times following a restart of *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. (Bug #29565) * *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. `--help' did not display any information about the `-a' option. (Bug #29509) * The cluster log was formatted inconsistently and contained extraneous newline characters. (Bug #25064) * Online `ALTER' operations involving a column whose data type has an implicit default value left behind temporary `.frm' files, causing subsequent *Note `DROP DATABASE': drop-database. statements to fail. (Bug #31097) * Transactions were committed prematurely when *Note `LOCK TABLE': lock-tables. and `SET autocommit = 0' were used together. (Bug #30996) * The *Note `mysqld_safe': mysqld-safe. script contained a syntax error. (Bug #30624)  File: manual.info, Node: mysql-cluster-news-5-1-22-ndb-6-2-6, Next: mysql-cluster-news-5-1-22-ndb-6-2-5, Prev: mysql-cluster-news-5-1-22-ndb-6-2-7, Up: mysql-cluster-news-6-2 17.7.5.14 Changes in MySQL Cluster NDB 6.2.6 (5.1.22-ndb-6.2.6) (20 September 2007) ................................................................................... This is a bugfix release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.2 release. Obtaining MySQL Cluster NDB 6.2 You can download the latest MySQL Cluster NDB 6.2 source code and binaries for supported platforms from http://dev.mysql.com/downloads/cluster/. This Beta release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.2 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.22 (see *Note news-5-1-22::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * Mapping of *Note `NDB': mysql-cluster. error codes to MySQL storage engine error codes has been improved. (Bug #28423) *Bugs fixed:* * *Partitioning*: *Note `EXPLAIN PARTITIONS': explain. reported partition usage by queries on *Note `NDB': mysql-cluster. tables according to the standard MySQL hash function than the hash function used in the *Note `NDB': mysql-cluster. storage engine. (Bug #29550) * When an *Note `NDB': mysql-cluster. event was left behind but the corresponding table was later recreated and received a new table ID, the event could not be dropped. (Bug #30877) * Attempting to restore a backup made on a cluster host using one endian to a machine using the other endian could cause the cluster to fail. (Bug #29674) * The description of the `--print' option provided in the output from *Note `ndb_restore `--help' ': mysql-cluster-programs-ndb-restore. was incorrect. (Bug #27683) * Restoring a backup made on a cluster host using one endian to a machine using the other endian failed for *Note `BLOB': blob. and *Note `DATETIME': datetime. columns. (Bug #27543, Bug #30024) * An insufficiently descriptive and potentially misleading Error 4006 (`Connect failure - out of connection objects...') was produced when either of the following two conditions occurred: 1. There were no more transaction records in the transaction coordinator 2. An *Note `NDB': mysql-cluster. object in the NDB API was initialized with insufficient parallelism Separate error messages are now generated for each of these two cases. (Bug #11313) * For micro-GCPs, the assignment of `fake' CGI events no longer cause buckets to be sent out of order. Now, when assigning a GCI to a non-GCI event (that is, creating a pseudo-GCI or `fake' CGI), the GCI that is to arrive is always initiated, even if no known GCI exists, which could occur in the event of a node failure. (Bug #30884)  File: manual.info, Node: mysql-cluster-news-5-1-22-ndb-6-2-5, Next: mysql-cluster-news-5-1-19-ndb-6-2-4, Prev: mysql-cluster-news-5-1-22-ndb-6-2-6, Up: mysql-cluster-news-6-2 17.7.5.15 Changes in MySQL Cluster NDB 6.2.5 (5.1.22-ndb-6.2.5) (06 September 2007 General Availability) ........................................................................................................ This is a bugfix release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.2 release. Obtaining MySQL Cluster NDB 6.2 You can download the latest MySQL Cluster NDB 6.2 source code and binaries for supported platforms from http://dev.mysql.com/downloads/cluster/. This Beta release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.2 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.22 (see *Note news-5-1-22::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * The following improvements have been made in the *Note `ndb_size.pl': mysql-cluster-programs-ndb-size-pl. utility: * The script can now be used with multiple databases; lists of databases and tables can also be excluded from analysis. * Schema name information has been added to index table calculations. * The database name is now an optional parameter, the exclusion of which causes all databases to be examined. * If selecting from `INFORMATION_SCHEMA' fails, the script now attempts to fall back to *Note `SHOW TABLES': show-tables. * A `--real_table_name' option has been added; this designates a table to handle unique index size calculations. * The report title has been amended to cover cases where more than one database is being analyzed. Support for a `--socket' option was also added. For more information, see *Note mysql-cluster-programs-ndb-size-pl::. (Bug #28683, Bug #28253) * Online `ADD COLUMN', `ADD INDEX', and `DROP INDEX' operations can now be performed explicitly for *Note `NDB': mysql-cluster. tables--that is, without copying or locking of the affected tables--using `ALTER ONLINE TABLE'. Indexes can also be created and dropped online using *Note `CREATE INDEX': create-index. and *Note `DROP INDEX': drop-index, respectively, using the `ONLINE' keyword. You can force operations that would otherwise be performed online to be done offline using the `OFFLINE' keyword. Renaming of tables and columns for *Note `NDB': mysql-cluster. and `MyISAM' tables is performed in place without table copying. For more information, see *Note alter-table-online-operations::, *Note create-index::, and *Note drop-index::. * It is now possible to control whether fixed-width or variable-width storage is used for a given column of an *Note `NDB': mysql-cluster. table by means of the `COLUMN_FORMAT' specifier as part of the column's definition in a *Note `CREATE TABLE': create-table. or *Note `ALTER TABLE': alter-table. statement. It is also possible to control whether a given column of an *Note `NDB': mysql-cluster. table is stored in memory or on disk, using the `STORAGE' specifier as part of the column's definition in a *Note `CREATE TABLE': create-table. or *Note `ALTER TABLE': alter-table. statement. For permitted values and other information about `COLUMN_FORMAT' and `STORAGE', see *Note create-table::. * A new cluster management server startup option `--bind-address' makes it possible to restrict management client connections to *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. to a single host and port. For more information, see *Note mysql-cluster-programs-ndb-mgmd::. * *Cluster Replication*: The protocol for handling global checkpoints has been changed. It is now possible to control how often the GCI number is updated, and how often global checkpoints are written to disk, using the `TimeBetweenEpochs' configuration parameter. This improves the reliability and performance of MySQL Cluster Replication. GCPs handled using the new protocol are sometimes referred to as `micro-GCPs'. *Bugs fixed:* * When handling *Note `BLOB': blob. columns, the addition of read locks to the lock queue was not handled correctly. (Bug #30764) * Discovery of *Note `NDB': mysql-cluster. tables did not work correctly with `INFORMATION_SCHEMA'. (Bug #30667) * A file system close operation could fail during a node or system restart. (Bug #30646) * Using the `--ndb-cluster-connection-pool' option for *Note `mysqld': mysqld. caused DDL statements to be executed twice. (Bug #30598) * When creating an `NDB' table with a column that has `COLUMN_FORMAT = DYNAMIC', but the table tiself uses `ROW_FORMAT=FIXED', the table is considered dynamic, but any columns for which the row format is unspecified default to `FIXED'. Now in such cases the server issues the warning `Row format FIXED incompatible with dynamic attribute COLUMN_NAME'. (Bug #30276) * *Note `ndb_size.pl': mysql-cluster-programs-ndb-size-pl. failed on tables with *Note `FLOAT': numeric-types. columns whose definitions included commas (for example, `FLOAT(6,2)'). (Bug #29228) * Reads on *Note `BLOB': blob. columns were not locked when they needed to be to guarantee consistency. (Bug #29102) See also Bug #31482. * A query using joins between several large tables and requiring unique index lookups failed to complete, eventually returning `Uknown Error' after a very long period of time. This occurred due to inadequate handling of instances where the Transaction Coordinator ran out of `TransactionBufferMemory', when the cluster should have returned NDB error code 4012 (`Request ndbd time-out'). (Bug #28804) * An attempt to perform a `SELECT ... FROM INFORMATION_SCHEMA.TABLES' whose result included information about *Note `NDB': mysql-cluster. tables for which the user had no privileges crashed the MySQL Server on which the query was performed. (Bug #26793) * *Cluster Replication*: Cluster replication did not handle large *Note `VARCHAR': char. columns correctly. (Bug #29904) * *Cluster Replication*: An issue with the `mysql.ndb_apply_status' table could cause *Note `NDB': mysql-cluster. schema autodiscovery to fail in certain rare circumstances. (Bug #20872) * *Cluster API*: A call to `CHECK_TIMEDOUT_RET()' in `mgmapi.cpp' should have been a call to `DBUG_CHECK_TIMEDOUT_RET()'. (Bug #30681)  File: manual.info, Node: mysql-cluster-news-5-1-19-ndb-6-2-4, Next: mysql-cluster-news-5-1-19-ndb-6-2-3, Prev: mysql-cluster-news-5-1-22-ndb-6-2-5, Up: mysql-cluster-news-6-2 17.7.5.16 Changes in MySQL Cluster NDB 6.2.4 (5.1.19-ndb-6.2.4) (04 July 2007) .............................................................................. This is a bugfix release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.2 release. Obtaining MySQL Cluster NDB 6.2 You can download the latest MySQL Cluster NDB 6.2 source code and binaries for supported platforms from http://dev.mysql.com/downloads/cluster/. This Beta release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.2 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.19 (see *Note news-5-1-19::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Bugs fixed:* * When restarting a data node, queries could hang during that node's start phase 5, and continue only after the node had entered phase 6. (Bug #29364) * Replica redo logs were inconsistently handled during a system restart. (Bug #29354) * *Disk Data*: Performing Disk Data schema operations during a node restart could cause forced shutdowns of other data nodes. (Bug #29501) * *Disk Data*: Disk data meta-information that existed in *Note `ndbd': mysql-cluster-programs-ndbd. might not be visible to *Note `mysqld': mysqld. (Bug #28720) * *Disk Data*: The number of free extents was incorrectly reported for some tablespaces. (Bug #28642) * Batching of transactions was not handled correctly in some cases. (Bug #29525)  File: manual.info, Node: mysql-cluster-news-5-1-19-ndb-6-2-3, Next: mysql-cluster-news-5-1-18-ndb-6-2-2, Prev: mysql-cluster-news-5-1-19-ndb-6-2-4, Up: mysql-cluster-news-6-2 17.7.5.17 Changes in MySQL Cluster NDB 6.2.3 (5.1.19-ndb-6.2.3) (02 July 2007) .............................................................................. This is a bugfix release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.2 release. Obtaining MySQL Cluster NDB 6.2 You can download the latest MySQL Cluster NDB 6.2 source code and binaries for supported platforms from http://dev.mysql.com/downloads/cluster/. This Beta release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.2 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.18 (see *Note news-5-1-18::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Bugs fixed:* * When restarting a data node, queries could hang during that node's start phase 5, and continue only after the node had entered phase 6. (Bug #29364) * Replica redo logs were inconsistently handled during a system restart. (Bug #29354) * *Disk Data*: Performing Disk Data schema operations during a node restart could cause forced shutdowns of other data nodes. (Bug #29501) * *Disk Data*: Disk data meta-information that existed in *Note `ndbd': mysql-cluster-programs-ndbd. might not be visible to *Note `mysqld': mysqld. (Bug #28720) * *Disk Data*: The number of free extents was incorrectly reported for some tablespaces. (Bug #28642) * Batching of transactions was not handled correctly in some cases. (Bug #29525)  File: manual.info, Node: mysql-cluster-news-5-1-18-ndb-6-2-2, Next: mysql-cluster-news-5-1-18-ndb-6-2-1, Prev: mysql-cluster-news-5-1-19-ndb-6-2-3, Up: mysql-cluster-news-6-2 17.7.5.18 Changes in MySQL Cluster NDB 6.2.2 (5.1.18-ndb-6.2.2) (07 May 2007) ............................................................................. This is a bugfix release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.2 release. Obtaining MySQL Cluster NDB 6.2 You can download the latest MySQL Cluster NDB 6.2 source code and binaries for supported platforms from http://dev.mysql.com/downloads/cluster/. This Beta release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.2 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.18 (see *Note news-5-1-18::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * New cluster management client `DUMP' commands were added to aid in tracking transactions, scan operations, and locks. See `DUMP 2350' (http://dev.mysql.com/doc/ndbapi/en/ndb-internals-dump-command-2350.html), `DUMP 2352' (http://dev.mysql.com/doc/ndbapi/en/ndb-internals-dump-command-2352.html), and `DUMP 2550' (http://dev.mysql.com/doc/ndbapi/en/ndb-internals-dump-command-2550.html), for more information. * Added the *Note `mysqld': mysqld. option `--ndb-cluster-connection-pool' that enables a single MySQL server to use multiple connections to the cluster. This enables scaling out using multiple MySQL clients per SQL node instead of or in addition to using multiple SQL nodes with the cluster. For more information about this option, see *Note mysql-cluster-options-variables::.  File: manual.info, Node: mysql-cluster-news-5-1-18-ndb-6-2-1, Next: mysql-cluster-news-5-1-16-ndb-6-2-0, Prev: mysql-cluster-news-5-1-18-ndb-6-2-2, Up: mysql-cluster-news-6-2 17.7.5.19 Changes in MySQL Cluster NDB 6.2.1 (5.1.18-ndb-6.2.1) (30 April 2007) ............................................................................... This is a Beta development release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.2 release. Obtaining MySQL Cluster NDB 6.2 You can download the latest MySQL Cluster NDB 6.2 source code and binaries for supported platforms from http://dev.mysql.com/downloads/cluster/. This Beta release incorporates all bugfixes and changes made in the previous MySQL Cluster NDB 6.2 release, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.18 (see *Note news-5-1-18::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Bugs fixed:* * Multiple operations involving deletes followed by reads were not handled correctly. *Note*: This issue could also affect MySQL Cluster Replication. (Bug #28276) * *Cluster API*: Using `NdbBlob::writeData()' to write data in the middle of an existing blob value (that is, updating the value) could overwrite some data past the end of the data to be changed. (Bug #27018) * Incorrect handling of fragmentation in a node takeover during a restart could cause stale data to be copied to the starting node, leading eventually to failure of the node. (Bug #27434) * An incorrect assertion was made when sending a `TCKEYFAILREF' or `TCKEYCONF' message to a failed data node. (Bug #26814)  File: manual.info, Node: mysql-cluster-news-5-1-16-ndb-6-2-0, Prev: mysql-cluster-news-5-1-18-ndb-6-2-1, Up: mysql-cluster-news-6-2 17.7.5.20 Changes in MySQL Cluster NDB 6.2.0 (5.1.16-ndb-6.2.0) (03 March 2007 Beta) .................................................................................... This is the first MySQL Cluster NDB 6.2 development release, based on version 6.2 of the *Note `NDBCLUSTER': mysql-cluster. storage engine. Obtaining MySQL Cluster NDB 6.2 You can download the latest MySQL Cluster NDB 6.2 source code and binaries for supported platforms from http://dev.mysql.com/downloads/cluster/. This Beta release incorporates bugfixes and changes made in previous MySQL Cluster releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.16 (see *Note news-5-1-16::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * An `--ndb-wait-connected' option has been added for *Note `mysqld': mysqld. When used, it causes *Note `mysqld': mysqld. wait a specified amount of time to be connected to the cluster before accepting client connections. * *Cluster API*: The `Ndb::startTransaction()' method now provides an alternative interface for starting a transaction. * *Cluster API*: It is now possible to iterate over all existing *Note `NDB': mysql-cluster. objects using three new methods of the `Ndb_cluster_connection' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndb-cluster-connection.html#ndb-ndb-cluster-connection) class: * `lock_ndb_objects()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndb-cluster-connection-methods.html#ndb-ndb-cluster-connection-lock-ndb-objects) * `get_next_ndb_object()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndb-cluster-connection-methods.html#ndb-ndb-cluster-connection-get-next-ndb-object) * `unlock_ndb_objects()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndb-cluster-connection-methods.html#ndb-ndb-cluster-connection-unlock-ndb-objects) * It is now possible to disable arbitration by setting `ArbitrationRank' equal to `0' on all nodes. * A new `TcpBind_INADDR_ANY' configuration parameter enables data nodes node to bind `INADDR_ANY' instead of a host name or IP address in the `config.ini' file. * Memory allocation has been improved on 32-bit architectures that enables using close to 3GB for `DataMemory' and `IndexMemory' combined.  File: manual.info, Node: mysql-cluster-news-6-1, Next: mysql-cluster-news-series, Prev: mysql-cluster-news-6-2, Up: mysql-cluster-news 17.7.6 Changes in MySQL Cluster NDB 6.1 --------------------------------------- * Menu: * mysql-cluster-news-5-1-15-ndb-6-1-23:: Changes in MySQL Cluster NDB 6.1.23 (5.1.15-ndb-6.1.23) (20 November 2007) * mysql-cluster-news-5-1-15-ndb-6-1-22:: Changes in MySQL Cluster NDB 6.1.22 (5.1.15-ndb-6.1.22) (19 October 2007) * mysql-cluster-news-5-1-15-ndb-6-1-21:: Changes in MySQL Cluster NDB 6.1.21 (5.1.15-ndb-6.1.21) (01 October 2007) * mysql-cluster-news-5-1-15-ndb-6-1-20:: Changes in MySQL Cluster NDB 6.1.20 (5.1.15-ndb-6.1.20) (14 September 2007) * mysql-cluster-news-5-1-15-ndb-6-1-19:: Changes in MySQL Cluster NDB 6.1.19 (5.1.15-ndb-6.1.19) (01 August 2007) * mysql-cluster-news-5-1-15-ndb-6-1-18:: Changes in MySQL Cluster NDB 6.1.18 (5.1.15-ndb-6.1.18) (Not released) * mysql-cluster-news-5-1-15-ndb-6-1-17:: Changes in MySQL Cluster NDB 6.1.17 (5.1.15-ndb-6.1.17) (03 July 2007) * mysql-cluster-news-5-1-15-ndb-6-1-16:: Changes in MySQL Cluster NDB 6.1.16 (5.1.15-ndb-6.1.16) (29 June 2007) * mysql-cluster-news-5-1-15-ndb-6-1-15:: Changes in MySQL Cluster NDB 6.1.15 (5.1.15-ndb-6.1.15) (20 June 2007) * mysql-cluster-news-5-1-15-ndb-6-1-14:: Changes in MySQL Cluster NDB 6.1.14 (5.1.15-ndb-6.1.14) (19 June 2007) * mysql-cluster-news-5-1-15-ndb-6-1-13:: Changes in MySQL Cluster NDB 6.1.13 (5.1.15-ndb-6.1.13) (15 June 2007) * mysql-cluster-news-5-1-15-ndb-6-1-12:: Changes in MySQL Cluster NDB 6.1.12 (5.1.15-ndb-6.1.12) (13 June 2007) * mysql-cluster-news-5-1-15-ndb-6-1-11:: Changes in MySQL Cluster NDB 6.1.11 (5.1.15-ndb-6.1.11) (06 June 2007) * mysql-cluster-news-5-1-15-ndb-6-1-10:: Changes in MySQL Cluster NDB 6.1.10 (5.1.15-ndb-6.1.10) (30 May 2007) * mysql-cluster-news-5-1-15-ndb-6-1-9:: Changes in MySQL Cluster NDB 6.1.9 (5.1.15-ndb-6.1.9) (24 May 2007) * mysql-cluster-news-5-1-15-ndb-6-1-8:: Changes in MySQL Cluster NDB 6.1.8 (5.1.15-ndb-6.1.8) (05 May 2007) * mysql-cluster-news-5-1-15-ndb-6-1-7:: Changes in MySQL Cluster NDB 6.1.7 (5.1.15-ndb-6.1.7) (05 May 2007) * mysql-cluster-news-5-1-15-ndb-6-1-6:: Changes in MySQL Cluster NDB 6.1.6 (5.1.15-ndb-6.1.6) (Not released) * mysql-cluster-news-5-1-15-ndb-6-1-5:: Changes in MySQL Cluster NDB 6.1.5 (5.1.15-ndb-6.1.5) (15 March 2007) * mysql-cluster-news-5-1-15-ndb-6-1-4:: Changes in MySQL Cluster NDB 6.1.4 (5.1.15-ndb-6.1.4) (09 March 2007) * mysql-cluster-news-5-1-15-ndb-6-1-3:: Changes in MySQL Cluster NDB 6.1.3 (5.1.15-ndb-6.1.3) (25 February 2007) * mysql-cluster-news-5-1-15-ndb-6-1-2:: Changes in MySQL Cluster NDB 6.1.2 (5.1.15-ndb-6.1.2) (07 February 2007) * mysql-cluster-news-5-1-15-ndb-6-1-1:: Changes in MySQL Cluster NDB 6.1.1 (5.1.15-ndb-6.1.1) (01 February 2007) * mysql-cluster-news-5-1-14-ndb-6-1-0:: Changes in MySQL Cluster NDB 6.1.0 (5.1.14-ndb-6.1.0) (20 December 2006) This section contains change history information for MySQL Cluster releases based on version 6.1 of the *Note `NDBCLUSTER': mysql-cluster. storage engine. For an overview of features that were added added in MySQL Cluster NDB 6.1, see *Note mysql-cluster-development-5-1-ndb-6-1::. *Note*: MySQL Cluster NDB 6.1 is no longer being developed or maintained, and the information presented in the next few sections should be considered to be of historical interest only. If you are using MySQL Cluster NDB 6.1, you should upgrade as soon as possible to the most recent version of MySQL Cluster NDB 6.2 or later MySQL Cluster release series.  File: manual.info, Node: mysql-cluster-news-5-1-15-ndb-6-1-23, Next: mysql-cluster-news-5-1-15-ndb-6-1-22, Prev: mysql-cluster-news-6-1, Up: mysql-cluster-news-6-1 17.7.6.1 Changes in MySQL Cluster NDB 6.1.23 (5.1.15-ndb-6.1.23) (20 November 2007) ................................................................................... This is a bugfix release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.1 release. MySQL Cluster NDB 6.1 no longer in development MySQL Cluster NDB 6.1 (formerly known as `MySQL Cluster Carrier Grade Edition 6.1.x') is no longer being developed or maintained; if you are using a MySQL Cluster NDB 6.1 release, you should consider upgrading to MySQL Cluster NDB 6.2 or 6.3. This Beta release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.1 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.15 (see *Note news-5-1-15::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Bugs fixed:* * The *Note `NDB': mysql-cluster. storage engine code was not safe for strict-alias optimization in `gcc' 4.2.1. (Bug #31761) * *Cluster Replication*: Under certain conditions, the slave stopped processing relay logs. This resulted in the logs never being cleared and the slave eventually running out of disk space. (Bug #31958)  File: manual.info, Node: mysql-cluster-news-5-1-15-ndb-6-1-22, Next: mysql-cluster-news-5-1-15-ndb-6-1-21, Prev: mysql-cluster-news-5-1-15-ndb-6-1-23, Up: mysql-cluster-news-6-1 17.7.6.2 Changes in MySQL Cluster NDB 6.1.22 (5.1.15-ndb-6.1.22) (19 October 2007) .................................................................................. This is a bugfix release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.1 release. MySQL Cluster NDB 6.1 no longer in development MySQL Cluster NDB 6.1 (formerly known as `MySQL Cluster Carrier Grade Edition 6.1.x') is no longer being developed or maintained; if you are using a MySQL Cluster NDB 6.1 release, you should consider upgrading to MySQL Cluster NDB 6.2 or 6.3. This Beta release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.1 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.15 (see *Note news-5-1-15::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Bugs fixed:* * It was possible in some cases for a node group to be `lost' due to missed local checkpoints following a system restart. (Bug #31525) * *Cluster Replication*: *Replication*: A node failure during replication could lead to buckets out of order; now active subscribers are checked for, rather than empty buckets. (Bug #31701)  File: manual.info, Node: mysql-cluster-news-5-1-15-ndb-6-1-21, Next: mysql-cluster-news-5-1-15-ndb-6-1-20, Prev: mysql-cluster-news-5-1-15-ndb-6-1-22, Up: mysql-cluster-news-6-1 17.7.6.3 Changes in MySQL Cluster NDB 6.1.21 (5.1.15-ndb-6.1.21) (01 October 2007) .................................................................................. This is a bugfix release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.1 release. MySQL Cluster NDB 6.1 no longer in development MySQL Cluster NDB 6.1 (formerly known as `MySQL Cluster Carrier Grade Edition 6.1.x') is no longer being developed or maintained; if you are using a MySQL Cluster NDB 6.1 release, you should consider upgrading to MySQL Cluster NDB 6.2 or 6.3. This Beta release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.1 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.15 (see *Note news-5-1-15::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Bugs fixed:* * A node failure during a local checkpoint could lead to a subsequent failure of the cluster during a system restart. (Bug #31257) * A cluster restart could sometimes fail due to an issue with table IDs. (Bug #30975)  File: manual.info, Node: mysql-cluster-news-5-1-15-ndb-6-1-20, Next: mysql-cluster-news-5-1-15-ndb-6-1-19, Prev: mysql-cluster-news-5-1-15-ndb-6-1-21, Up: mysql-cluster-news-6-1 17.7.6.4 Changes in MySQL Cluster NDB 6.1.20 (5.1.15-ndb-6.1.20) (14 September 2007) .................................................................................... This is a bugfix release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.1 release. MySQL Cluster NDB 6.1 no longer in development MySQL Cluster NDB 6.1 (formerly known as `MySQL Cluster Carrier Grade Edition 6.1.x') is no longer being developed or maintained; if you are using a MySQL Cluster NDB 6.1 release, you should consider upgrading to MySQL Cluster NDB 6.2 or 6.3. This Beta release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.1 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.15 (see *Note news-5-1-15::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Bugs fixed:* * *Cluster Replication*: *Replication*: Incorrect handling of *Note `INSERT': insert. plus *Note `DELETE': delete. operations with regard to local checkpoints caused data node failures in multi-master replication setups. (Bug #30914)  File: manual.info, Node: mysql-cluster-news-5-1-15-ndb-6-1-19, Next: mysql-cluster-news-5-1-15-ndb-6-1-18, Prev: mysql-cluster-news-5-1-15-ndb-6-1-20, Up: mysql-cluster-news-6-1 17.7.6.5 Changes in MySQL Cluster NDB 6.1.19 (5.1.15-ndb-6.1.19) (01 August 2007) ................................................................................. This is a bugfix release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.1 release. MySQL Cluster NDB 6.1 no longer in development MySQL Cluster NDB 6.1 (formerly known as `MySQL Cluster Carrier Grade Edition 6.1.x') is no longer being developed or maintained; if you are using a MySQL Cluster NDB 6.1 release, you should consider upgrading to MySQL Cluster NDB 6.2 or 6.3. This Beta release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.1 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.15 (see *Note news-5-1-15::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * Whenever a TCP send buffer is over 80% full, temporary error 1218 (`Send Buffers overloaded in NDB kernel') is now returned. See SendBufferMemory for more information. * An `INFO' event is now sent if the time between global checkpoints is excessive, or if `DUMP 7901' is issued in the management client.  File: manual.info, Node: mysql-cluster-news-5-1-15-ndb-6-1-18, Next: mysql-cluster-news-5-1-15-ndb-6-1-17, Prev: mysql-cluster-news-5-1-15-ndb-6-1-19, Up: mysql-cluster-news-6-1 17.7.6.6 Changes in MySQL Cluster NDB 6.1.18 (5.1.15-ndb-6.1.18) (Not released) ............................................................................... This is a bugfix release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.1 release. MySQL Cluster NDB 6.1 no longer in development MySQL Cluster NDB 6.1 (formerly known as `MySQL Cluster Carrier Grade Edition 6.1.x') is no longer being developed or maintained; if you are using a MySQL Cluster NDB 6.1 release, you should consider upgrading to MySQL Cluster NDB 6.2 or 6.3. This Beta release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.1 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.15 (see *Note news-5-1-15::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Bugs fixed:* * When restarting a data node, queries could hang during that node's start phase 5, and continue only after the node had entered phase 6. (Bug #29364) * *Replication*: Storage engine error conditions in row-based replication were not correctly reported to the user. (Bug #29570) * *Disk Data*: Disk data meta-information that existed in *Note `ndbd': mysql-cluster-programs-ndbd. might not be visible to *Note `mysqld': mysqld. (Bug #28720) * *Disk Data*: The number of free extents was incorrectly reported for some tablespaces. (Bug #28642)  File: manual.info, Node: mysql-cluster-news-5-1-15-ndb-6-1-17, Next: mysql-cluster-news-5-1-15-ndb-6-1-16, Prev: mysql-cluster-news-5-1-15-ndb-6-1-18, Up: mysql-cluster-news-6-1 17.7.6.7 Changes in MySQL Cluster NDB 6.1.17 (5.1.15-ndb-6.1.17) (03 July 2007) ............................................................................... This is a bugfix release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.1 release. MySQL Cluster NDB 6.1 no longer in development MySQL Cluster NDB 6.1 (formerly known as `MySQL Cluster Carrier Grade Edition 6.1.x') is no longer being developed or maintained; if you are using a MySQL Cluster NDB 6.1 release, you should consider upgrading to MySQL Cluster NDB 6.2 or 6.3. This Beta release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.1 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.15 (see *Note news-5-1-15::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * *Cluster Replication*: *Replication*: Batching of updates on cluster replication slaves, enabled using the `--slave-allow-batching' option for *Note `mysqld': mysqld. *Bugs fixed:* * Replica redo logs were inconsistently handled during a system restart. (Bug #29354)  File: manual.info, Node: mysql-cluster-news-5-1-15-ndb-6-1-16, Next: mysql-cluster-news-5-1-15-ndb-6-1-15, Prev: mysql-cluster-news-5-1-15-ndb-6-1-17, Up: mysql-cluster-news-6-1 17.7.6.8 Changes in MySQL Cluster NDB 6.1.16 (5.1.15-ndb-6.1.16) (29 June 2007) ............................................................................... This is a bugfix release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.1 release. MySQL Cluster NDB 6.1 no longer in development MySQL Cluster NDB 6.1 (formerly known as `MySQL Cluster Carrier Grade Edition 6.1.x') is no longer being developed or maintained; if you are using a MySQL Cluster NDB 6.1 release, you should consider upgrading to MySQL Cluster NDB 6.2 or 6.3. This Beta release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.1 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.15 (see *Note news-5-1-15::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Bugs fixed:* * When a node failed to respond to a `COPY_GCI' signal as part of a global checkpoint, the master node was killed instead of the node that actually failed. (Bug #29331) * An invalid comparison made during `REDO' validation that could lead to an `Error while reading REDO log' condition. (Bug #29118) * The wrong data pages were sometimes invalidated following a global checkpoint. (Bug #29067) * If at least 2 files were involved in `REDO' invalidation, then file 0 of page 0 was not updated and so pointed to an invalid part of the redo log. (Bug #29057) * *Disk Data*: When dropping a page, the stack's bottom entry could sometime be left `cold' rather than `hot', violating the rules for stack pruning. (Bug #29176)  File: manual.info, Node: mysql-cluster-news-5-1-15-ndb-6-1-15, Next: mysql-cluster-news-5-1-15-ndb-6-1-14, Prev: mysql-cluster-news-5-1-15-ndb-6-1-16, Up: mysql-cluster-news-6-1 17.7.6.9 Changes in MySQL Cluster NDB 6.1.15 (5.1.15-ndb-6.1.15) (20 June 2007) ............................................................................... This is a bugfix release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.1 release. MySQL Cluster NDB 6.1 no longer in development MySQL Cluster NDB 6.1 (formerly known as `MySQL Cluster Carrier Grade Edition 6.1.x') is no longer being developed or maintained; if you are using a MySQL Cluster NDB 6.1 release, you should consider upgrading to MySQL Cluster NDB 6.2 or 6.3. This Beta release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.1 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.15 (see *Note news-5-1-15::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Bugs fixed:* * Memory corruption could occur due to a problem in the `DBTUP' kernel block. (Bug #29229)  File: manual.info, Node: mysql-cluster-news-5-1-15-ndb-6-1-14, Next: mysql-cluster-news-5-1-15-ndb-6-1-13, Prev: mysql-cluster-news-5-1-15-ndb-6-1-15, Up: mysql-cluster-news-6-1 17.7.6.10 Changes in MySQL Cluster NDB 6.1.14 (5.1.15-ndb-6.1.14) (19 June 2007) ................................................................................ This is a bugfix release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.1 release. MySQL Cluster NDB 6.1 no longer in development MySQL Cluster NDB 6.1 (formerly known as `MySQL Cluster Carrier Grade Edition 6.1.x') is no longer being developed or maintained; if you are using a MySQL Cluster NDB 6.1 release, you should consider upgrading to MySQL Cluster NDB 6.2 or 6.3. This Beta release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.1 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.15 (see *Note news-5-1-15::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Bugs fixed:* * In the event that two data nodes in the same node group and participating in a GCP crashed before they had written their respective `P0.sysfile' files, `QMGR' could refuse to start, issuing an invalid `Insufficient nodes for restart' error instead. (Bug #29167)  File: manual.info, Node: mysql-cluster-news-5-1-15-ndb-6-1-13, Next: mysql-cluster-news-5-1-15-ndb-6-1-12, Prev: mysql-cluster-news-5-1-15-ndb-6-1-14, Up: mysql-cluster-news-6-1 17.7.6.11 Changes in MySQL Cluster NDB 6.1.13 (5.1.15-ndb-6.1.13) (15 June 2007) ................................................................................ This is a bugfix release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.1 release. MySQL Cluster NDB 6.1 no longer in development MySQL Cluster NDB 6.1 (formerly known as `MySQL Cluster Carrier Grade Edition 6.1.x') is no longer being developed or maintained; if you are using a MySQL Cluster NDB 6.1 release, you should consider upgrading to MySQL Cluster NDB 6.2 or 6.3. This Beta release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.1 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.15 (see *Note news-5-1-15::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * Read ahead was implemented for backups of Disk Data tables, resulting in a 10 to 15% increase in backup speed of Disk Data tables. (Bug #29099) *Bugs fixed:* * *Cluster API*: `NdbApi.hpp' depended on `ndb_global.h', which was not actually installed, causing the compilation of programs that used `NdbApi.hpp' to fail. (Bug #35853)  File: manual.info, Node: mysql-cluster-news-5-1-15-ndb-6-1-12, Next: mysql-cluster-news-5-1-15-ndb-6-1-11, Prev: mysql-cluster-news-5-1-15-ndb-6-1-13, Up: mysql-cluster-news-6-1 17.7.6.12 Changes in MySQL Cluster NDB 6.1.12 (5.1.15-ndb-6.1.12) (13 June 2007) ................................................................................ This is a bugfix release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.1 release. MySQL Cluster NDB 6.1 no longer in development MySQL Cluster NDB 6.1 (formerly known as `MySQL Cluster Carrier Grade Edition 6.1.x') is no longer being developed or maintained; if you are using a MySQL Cluster NDB 6.1 release, you should consider upgrading to MySQL Cluster NDB 6.2 or 6.3. This Beta release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.1 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.15 (see *Note news-5-1-15::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * New cluster management client `DUMP' commands were added to aid in tracking transactions, scan operations, and locks. See `DUMP 2350' (http://dev.mysql.com/doc/ndbapi/en/ndb-internals-dump-command-2350.html), `DUMP 2352' (http://dev.mysql.com/doc/ndbapi/en/ndb-internals-dump-command-2352.html), and `DUMP 2550' (http://dev.mysql.com/doc/ndbapi/en/ndb-internals-dump-command-2550.html). * Backup dump output was extended to provide more information. *Bugs fixed:* * It is now possible to set the maximum size of the allocation unit for table memory using the `MaxAllocate' configuration parameter. (Bug #29044)  File: manual.info, Node: mysql-cluster-news-5-1-15-ndb-6-1-11, Next: mysql-cluster-news-5-1-15-ndb-6-1-10, Prev: mysql-cluster-news-5-1-15-ndb-6-1-12, Up: mysql-cluster-news-6-1 17.7.6.13 Changes in MySQL Cluster NDB 6.1.11 (5.1.15-ndb-6.1.11) (06 June 2007) ................................................................................ This is a bugfix release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.1 release. MySQL Cluster NDB 6.1 no longer in development MySQL Cluster NDB 6.1 (formerly known as `MySQL Cluster Carrier Grade Edition 6.1.x') is no longer being developed or maintained; if you are using a MySQL Cluster NDB 6.1 release, you should consider upgrading to MySQL Cluster NDB 6.2 or 6.3. This Beta release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.1 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.15 (see *Note news-5-1-15::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * *Important Change*: The `TimeBetweenWatchdogCheckInitial' configuration parameter was added to enable setting of a separate watchdog timeout for memory allocation during startup of the data nodes. (Bug #28899) * A new configuration parameter `ODirect' causes *Note `NDB': mysql-cluster. to attempt using `O_DIRECT' writes for LCP, backups, and redo logs, often lowering CPU usage. * It is now possible to set the size of redo log files (fragment log files) using the `FragmentLogFileSize' configuration parameter. *Bugs fixed:* * Having large amounts of memory locked caused swapping to disk. (Bug #28751) * LCP files were not removed following an initial system restart. (Bug #28726) * *Disk Data*: Repeated *Note `INSERT': insert. and *Note `DELETE': delete. operations on a Disk Data table having one or more large *Note `VARCHAR': char. columns could cause data nodes to fail. (Bug #20612)  File: manual.info, Node: mysql-cluster-news-5-1-15-ndb-6-1-10, Next: mysql-cluster-news-5-1-15-ndb-6-1-9, Prev: mysql-cluster-news-5-1-15-ndb-6-1-11, Up: mysql-cluster-news-6-1 17.7.6.14 Changes in MySQL Cluster NDB 6.1.10 (5.1.15-ndb-6.1.10) (30 May 2007) ............................................................................... This is a bugfix release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.1 release. MySQL Cluster NDB 6.1 no longer in development MySQL Cluster NDB 6.1 (formerly known as `MySQL Cluster Carrier Grade Edition 6.1.x') is no longer being developed or maintained; if you are using a MySQL Cluster NDB 6.1 release, you should consider upgrading to MySQL Cluster NDB 6.2 or 6.3. This Beta release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.1 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.15 (see *Note news-5-1-15::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * A new `times' printout was added in the *Note `ndbd': mysql-cluster-programs-ndbd. watchdog thread. * Some unneeded printouts in the *Note `ndbd': mysql-cluster-programs-ndbd. out file were removed. * The names of some log and other files were changed to avoid issues with the `tar' command's 99-character file name limit. *Bugs fixed:* * A regression in the heartbeat monitoring code could lead to node failure under high load. This issue affected MySQL 5.1.19 and MySQL Cluster NDB 6.1.10 only. (Bug #28783) * A corrupt schema file could cause a `File already open' error. (Bug #28770) * Setting `InitialNoOfOpenFiles' equal to `MaxNoOfOpenFiles' caused an error. This was due to the fact that the actual value of `MaxNoOfOpenFiles' as used by the cluster was offset by 1 from the value set in `config.ini'. (Bug #28749) * A race condition could result when nonmaster nodes (in addition to the master node) tried to update active status due to a local checkpoint (that is, between `NODE_FAILREP' and `COPY_GCIREQ' events). Now only the master updates the active status. (Bug #28717) * A fast global checkpoint under high load with high usage of the redo buffer caused data nodes to fail. (Bug #28653) * *Disk Data*: When loading data into a cluster following a version upgrade, the data nodes could forcibly shut down due to page and buffer management failures (that is, `ndbrequire' failures in `PGMAN'). (Bug #28525)  File: manual.info, Node: mysql-cluster-news-5-1-15-ndb-6-1-9, Next: mysql-cluster-news-5-1-15-ndb-6-1-8, Prev: mysql-cluster-news-5-1-15-ndb-6-1-10, Up: mysql-cluster-news-6-1 17.7.6.15 Changes in MySQL Cluster NDB 6.1.9 (5.1.15-ndb-6.1.9) (24 May 2007) ............................................................................. This is a bugfix release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.1 release. MySQL Cluster NDB 6.1 no longer in development MySQL Cluster NDB 6.1 (formerly known as `MySQL Cluster Carrier Grade Edition 6.1.x') is no longer being developed or maintained; if you are using a MySQL Cluster NDB 6.1 release, you should consider upgrading to MySQL Cluster NDB 6.2 or 6.3. This Beta release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.1 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.15 (see *Note news-5-1-15::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Bugs fixed:* * When an API node sent more than 1024 signals in a single batch, *Note `NDB': mysql-cluster. would process only the first 1024 of these, and then hang. (Bug #28443) * *Disk Data*: The cluster backup process scanned in `ACC' index order, which had bad effects for disk data. (Bug #28593)  File: manual.info, Node: mysql-cluster-news-5-1-15-ndb-6-1-8, Next: mysql-cluster-news-5-1-15-ndb-6-1-7, Prev: mysql-cluster-news-5-1-15-ndb-6-1-9, Up: mysql-cluster-news-6-1 17.7.6.16 Changes in MySQL Cluster NDB 6.1.8 (5.1.15-ndb-6.1.8) (05 May 2007) ............................................................................. This is a bugfix release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.1 release. MySQL Cluster NDB 6.1 no longer in development MySQL Cluster NDB 6.1 (formerly known as `MySQL Cluster Carrier Grade Edition 6.1.x') is no longer being developed or maintained; if you are using a MySQL Cluster NDB 6.1 release, you should consider upgrading to MySQL Cluster NDB 6.2 or 6.3. This Beta release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.1 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.15 (see *Note news-5-1-15::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Bugs fixed:* * Local checkpoint files relating to dropped *Note `NDB': mysql-cluster. tables were not removed. (Bug #28348) * Repeated insertion of data generated by *Note `mysqldump': mysqldump. into *Note `NDB': mysql-cluster. tables could eventually lead to failure of the cluster. (Bug #27437) * *Disk Data*: Extremely large inserts into Disk Data tables could lead to data node failure in some circumstances. (Bug #27942) * *Cluster API*: In a multi-operation transaction, a delete operation followed by the insertion of an implicit `NULL' failed to overwrite an existing value. (Bug #20535) * Setting `MaxNoOfTables' very low and relative to `DataMemory' caused `Out of memory in Ndb Kernel' errors when inserting relatively small amounts of data into NDB tables. (Bug #24173)  File: manual.info, Node: mysql-cluster-news-5-1-15-ndb-6-1-7, Next: mysql-cluster-news-5-1-15-ndb-6-1-6, Prev: mysql-cluster-news-5-1-15-ndb-6-1-8, Up: mysql-cluster-news-6-1 17.7.6.17 Changes in MySQL Cluster NDB 6.1.7 (5.1.15-ndb-6.1.7) (05 May 2007) ............................................................................. This is a bugfix release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.1 release. MySQL Cluster NDB 6.1 no longer in development MySQL Cluster NDB 6.1 (formerly known as `MySQL Cluster Carrier Grade Edition 6.1.x') is no longer being developed or maintained; if you are using a MySQL Cluster NDB 6.1 release, you should consider upgrading to MySQL Cluster NDB 6.2 or 6.3. This Beta release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.1 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.15 (see *Note news-5-1-15::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * *Cluster Replication*: *Incompatible Change*: The schema for the `ndb_apply_status' table in the `mysql' system database has changed. When upgrading to this release from a previous MySQL Cluster NDB 6.x or mainline MySQL 5.1 release, you must drop the `mysql.ndb_apply_status' table, then restart the server for the table to be re-created with the new schema. See *Note mysql-cluster-replication-schema::, for additional information. *Bugs fixed:* * The cluster waited 30 seconds instead of 30 milliseconds before reading table statistics. (Bug #28093) * Under certain rare circumstances, *Note `ndbd': mysql-cluster-programs-ndbd. could get caught in an infinite loop when one transaction took a read lock and then a second transaction attempted to obtain a write lock on the same tuple in the lock queue. (Bug #28073) * Under some circumstances, a node restart could fail to update the Global Checkpoint Index (GCI). (Bug #28023) * An *Note `INSERT': insert. followed by a delete *Note `DELETE': delete. on the same *Note `NDB': mysql-cluster. table caused a memory leak. (Bug #27756) This regression was introduced by Bug #20612. * Under certain rare circumstances performing a *Note `DROP TABLE': drop-table. or *Note `TRUNCATE TABLE': truncate-table. on an *Note `NDB': mysql-cluster. table could cause a node failure or forced cluster shutdown. (Bug #27581) * Memory usage of a *Note `mysqld': mysqld. process grew even while idle. (Bug #27560) * Performing a delete followed by an insert during a local checkpoint could cause a `Rowid already allocated' error. (Bug #27205) * *Cluster Replication*: *Disk Data*: An issue with replication of Disk Data tables could in some cases lead to node failure. (Bug #28161) * *Disk Data*: Changes to a Disk Data table made as part of a transaction could not be seen by the client performing the changes until the transaction had been committed. (Bug #27757) * *Disk Data*: When restarting a data node following the creation of a large number of Disk Data objects (approximately 200 such objects), the cluster could not assign a node ID to the restarting node. (Bug #25741) * *Disk Data*: Changing a column specification or issuing a *Note `TRUNCATE TABLE': truncate-table. statement on a Disk Data table caused the table to become an in-memory table. This fix supersedes an incomplete fix that was made for this issue in MySQL 5.1.15. (Bug #24667, Bug #25296) * *Cluster Replication*: Some queries that updated multiple tables were not backed up correctly. (Bug #27748) * *Cluster Replication*: It was possible for API nodes to begin interacting with the cluster subscription manager before they were fully connected to the cluster. (Bug #27728) * *Cluster Replication*: Under very high loads, checkpoints could be read or written with checkpoint indexes out of order. (Bug #27651) * *Cluster API*: An issue with the way in which the `Dictionary::listEvents()' method freed resources could sometimes lead to memory corruption. (Bug #27663) * *Note `mysqldump': mysqldump. could not dump log tables. (Bug #26121) * The `--with-readline' option for `configure' did not work for commercial source packages, but no error message was printed to that effect. Now a message is printed. (Bug #25530)  File: manual.info, Node: mysql-cluster-news-5-1-15-ndb-6-1-6, Next: mysql-cluster-news-5-1-15-ndb-6-1-5, Prev: mysql-cluster-news-5-1-15-ndb-6-1-7, Up: mysql-cluster-news-6-1 17.7.6.18 Changes in MySQL Cluster NDB 6.1.6 (5.1.15-ndb-6.1.6) (Not released) .............................................................................. This is a bugfix release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.1 release. MySQL Cluster NDB 6.1 no longer in development MySQL Cluster NDB 6.1 (formerly known as `MySQL Cluster Carrier Grade Edition 6.1.x') is no longer being developed or maintained; if you are using a MySQL Cluster NDB 6.1 release, you should consider upgrading to MySQL Cluster NDB 6.2 or 6.3. This Beta release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.1 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.15 (see *Note news-5-1-15::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * *Cluster Replication*: *Incompatible Change*: The schema for the `ndb_apply_status' table in the `mysql' system database has changed. When upgrading to this release from a previous MySQL Cluster NDB 6.x or mainline MySQL 5.1 release, you must drop the `mysql.ndb_apply_status' table, then restart the server for the table to be re-created with the new schema. See *Note mysql-cluster-replication-schema::, for additional information. *Bugs fixed:* * A data node failing while another data node was restarting could leave the cluster in an inconsistent state. In certain rare cases, this could lead to a race condition and the eventual forced shutdown of the cluster. (Bug #27466) * It was not possible to set `LockPagesInMainMemory' equal to `0'. (Bug #27291) * A race condition could sometimes occur if the node acting as master failed while node IDs were still being allocated during startup. (Bug #27286) * When a data node was taking over as the master node, a race condition could sometimes occur as the node was assuming responsibility for handling of global checkpoints. (Bug #27283) * *Note `mysqld': mysqld. could crash shortly after a data node failure following certain DML operations. (Bug #27169) * The same failed request from an API node could be handled by the cluster multiple times, resulting in reduced performance. (Bug #27087) * The failure of a data node while restarting could cause other data nodes to hang or crash. (Bug #27003) * *Note `mysqld': mysqld. processes would sometimes crash under high load. *Note*: This fix improves on and replaces a fix for this bug that was made in MySQL Cluster NDB 6.1.5. (Bug #26825) * *Disk Data*: *Note `DROP INDEX': drop-index. on a Disk Data table did not always move data from memory into the tablespace. (Bug #25877) * *Cluster Replication*: Trying to replicate a large number of frequent updates with a relatively small relay log (`max-relay-log-size' set to 1M or less) could cause the slave to crash. (Bug #27529) * *Cluster API*: An issue with the way in which the `Dictionary::listEvents()' method freed resources could sometimes lead to memory corruption. (Bug #27663) * *Cluster API*: A delete operation using a scan followed by an insert using a scan could cause a data node to fail. (Bug #27203)  File: manual.info, Node: mysql-cluster-news-5-1-15-ndb-6-1-5, Next: mysql-cluster-news-5-1-15-ndb-6-1-4, Prev: mysql-cluster-news-5-1-15-ndb-6-1-6, Up: mysql-cluster-news-6-1 17.7.6.19 Changes in MySQL Cluster NDB 6.1.5 (5.1.15-ndb-6.1.5) (15 March 2007) ............................................................................... This is a bugfix release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.1 release. MySQL Cluster NDB 6.1 no longer in development MySQL Cluster NDB 6.1 (formerly known as `MySQL Cluster Carrier Grade Edition 6.1.x') is no longer being developed or maintained; if you are using a MySQL Cluster NDB 6.1 release, you should consider upgrading to MySQL Cluster NDB 6.2 or 6.3. This Beta release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.1 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.15 (see *Note news-5-1-15::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * *Cluster Replication*: *Incompatible Change*: The schema for the `ndb_apply_status' table in the `mysql' system database has changed. When upgrading to this release from a previous MySQL Cluster NDB 6.x or mainline MySQL 5.1 release, you must drop the `mysql.ndb_apply_status' table, then restart the server for the table to be re-created with the new schema. See *Note mysql-cluster-replication-schema::, for additional information. *Bugs fixed:* * Creating a table on one SQL node while in single user mode caused other SQL nodes to crash. (Bug #26997) * *Note `mysqld': mysqld. processes would sometimes crash under high load. *Note*: This fix was reverted in MySQL Cluster NDB 6.1.6. (Bug #26825) * An infinite loop in an internal logging function could cause trace logs to fill up with `Unknown Signal type' error messages and thus grow to unreasonable sizes. (Bug #26720) * *Disk Data*: When creating a log file group, setting `INITIAL_SIZE' to less than `UNDO_BUFFER_SIZE' caused data nodes to crash. (Bug #25743)  File: manual.info, Node: mysql-cluster-news-5-1-15-ndb-6-1-4, Next: mysql-cluster-news-5-1-15-ndb-6-1-3, Prev: mysql-cluster-news-5-1-15-ndb-6-1-5, Up: mysql-cluster-news-6-1 17.7.6.20 Changes in MySQL Cluster NDB 6.1.4 (5.1.15-ndb-6.1.4) (09 March 2007) ............................................................................... This is a bugfix release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.1 release. MySQL Cluster NDB 6.1 no longer in development MySQL Cluster NDB 6.1 (formerly known as `MySQL Cluster Carrier Grade Edition 6.1.x') is no longer being developed or maintained; if you are using a MySQL Cluster NDB 6.1 release, you should consider upgrading to MySQL Cluster NDB 6.2 or 6.3. This Beta release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.1 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.15 (see *Note news-5-1-15::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * An `--ndb-wait-connected' option has been added for *Note `mysqld': mysqld. When used, it causes *Note `mysqld': mysqld. wait a specified amount of time to be connected to the cluster before accepting client connections. * *Cluster API*: It is now possible to specify the transaction coordinator when starting a transaction. See `Ndb::startTransaction()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndb-methods.html#ndb-ndb-starttransaction), for more information. * *Cluster API*: It is now possible to iterate over all existing *Note `NDB': mysql-cluster. objects using three new methods of the `Ndb_cluster_connection' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndb-cluster-connection.html#ndb-ndb-cluster-connection) class: * `lock_ndb_objects()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndb-cluster-connection-methods.html#ndb-ndb-cluster-connection-lock-ndb-objects) * `get_next_ndb_object()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndb-cluster-connection-methods.html#ndb-ndb-cluster-connection-get-next-ndb-object) * `unlock_ndb_objects()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndb-cluster-connection-methods.html#ndb-ndb-cluster-connection-unlock-ndb-objects) * Data node memory allocation has been improved. On 32-bit platforms, it should now be possible to use close to 3GB RAM for `IndexMemory' and `DataMemory' combined. *Bugs fixed:* * Using only the `--print_data' option (and no other options) with *Note `ndb_restore': mysql-cluster-programs-ndb-restore. caused *Note `ndb_restore': mysql-cluster-programs-ndb-restore. to fail. (Bug #26741) This regression was introduced by Bug #14612. * An inadvertent use of unaligned data caused *Note `ndb_restore': mysql-cluster-programs-ndb-restore. to fail on some 64-bit platforms, including Sparc and Itanium-2. (Bug #26739) * Assigning a node ID greater than 63 to an SQL node caused an out of bounds error in *Note `mysqld': mysqld. It should now be possible to assign to SQL nodes node IDs up to 255. (Bug #26663)  File: manual.info, Node: mysql-cluster-news-5-1-15-ndb-6-1-3, Next: mysql-cluster-news-5-1-15-ndb-6-1-2, Prev: mysql-cluster-news-5-1-15-ndb-6-1-4, Up: mysql-cluster-news-6-1 17.7.6.21 Changes in MySQL Cluster NDB 6.1.3 (5.1.15-ndb-6.1.3) (25 February 2007) .................................................................................. This is a bugfix release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.1 release. MySQL Cluster NDB 6.1 no longer in development MySQL Cluster NDB 6.1 (formerly known as `MySQL Cluster Carrier Grade Edition 6.1.x') is no longer being developed or maintained; if you are using a MySQL Cluster NDB 6.1 release, you should consider upgrading to MySQL Cluster NDB 6.2 or 6.3. This Beta release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.1 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.15 (see *Note news-5-1-15::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * The *Note `ndbd_redo_log_reader': mysql-cluster-programs-ndbd-redo-log-reader. utility is now part of the default build. For more information, see *Note mysql-cluster-programs-ndbd-redo-log-reader::. * The *Note `ndb_show_tables': mysql-cluster-programs-ndb-show-tables. utility now displays information about table events. See *Note mysql-cluster-programs-ndb-show-tables::, for more information. * *Cluster API*: A new `listEvents()' method has been added to the `Dictionary' class. * It is now possible to disable arbitration by setting `ArbitrationRank = 0' on all management and SQL nodes. *Bugs fixed:* * An invalid pointer was returned following a `FSCLOSECONF' signal when accessing the REDO logs during a node restart or system restart. (Bug #26515) * The InvalidUndoBufferSize error used the same error code (763) as the IncompatibleVersions error. InvalidUndoBufferSize now uses its own error code (779). (Bug #26490) * The failure of a data node when restarting it with `--initial' could lead to failures of subsequent data node restarts. (Bug #26481) * Takeover for local checkpointing due to multiple failures of master nodes was sometimes incorrectly handled. (Bug #26457) * The `LockPagesInMainMemory' parameter was not read until after distributed communication had already started between cluster nodes. When the value of this parameter was `1', this could sometimes result in data node failure due to missed heartbeats. (Bug #26454) * Under some circumstances, following the restart of a management node, all data nodes would connect to it normally, but some of them subsequently failed to log any events to the management node. (Bug #26293) * No appropriate error message was provided when there was insufficient REDO log file space for the cluster to start. (Bug #25801) * A memory allocation failure in `SUMA' (the cluster Subscription Manager) could cause the cluster to crash. (Bug #25239) * The message `Error 0 in readAutoIncrementValue(): no Error' was written to the error log whenever *Note `SHOW TABLE STATUS': show-table-status. was performed on a Cluster table that did not have an `AUTO_INCREMENT' column. *Note*: This improves on and supersedes an earlier fix that was made for this issue in MySQL 5.1.12. (Bug #21033) * *Disk Data*: A memory overflow could occur with tables having a large amount of data stored on disk, or with queries using a very high degree of parallelism on Disk Data tables. (Bug #26514) * *Disk Data*: Use of a tablespace whose `INITIAL_SIZE' was greater than 1 GB could cause the cluster to crash. (Bug #26487)  File: manual.info, Node: mysql-cluster-news-5-1-15-ndb-6-1-2, Next: mysql-cluster-news-5-1-15-ndb-6-1-1, Prev: mysql-cluster-news-5-1-15-ndb-6-1-3, Up: mysql-cluster-news-6-1 17.7.6.22 Changes in MySQL Cluster NDB 6.1.2 (5.1.15-ndb-6.1.2) (07 February 2007) .................................................................................. This is a bugfix release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.1 release. MySQL Cluster NDB 6.1 no longer in development MySQL Cluster NDB 6.1 (formerly known as `MySQL Cluster Carrier Grade Edition 6.1.x') is no longer being developed or maintained; if you are using a MySQL Cluster NDB 6.1 release, you should consider upgrading to MySQL Cluster NDB 6.2 or 6.3. This Beta release incorporates all bugfixes and changes made in previous MySQL Cluster NDB 6.1 releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.15 (see *Note news-5-1-15::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Bugs fixed:* * Using node IDs greater than 48 could sometimes lead to incorrect memory access and a subsequent forced shutdown of the cluster. (Bug #26267)  File: manual.info, Node: mysql-cluster-news-5-1-15-ndb-6-1-1, Next: mysql-cluster-news-5-1-14-ndb-6-1-0, Prev: mysql-cluster-news-5-1-15-ndb-6-1-2, Up: mysql-cluster-news-6-1 17.7.6.23 Changes in MySQL Cluster NDB 6.1.1 (5.1.15-ndb-6.1.1) (01 February 2007) .................................................................................. This is a bugfix release, fixing recently discovered bugs in the previous MySQL Cluster NDB 6.1 release. MySQL Cluster NDB 6.1 no longer in development MySQL Cluster NDB 6.1 (formerly known as `MySQL Cluster Carrier Grade Edition 6.1.x') is no longer being developed or maintained; if you are using a MySQL Cluster NDB 6.1 release, you should consider upgrading to MySQL Cluster NDB 6.2 or 6.3. This Beta release incorporates all bugfixes and changes made in the previous MySQL Cluster NDB 6.1 release, as well as all bugfixes and feature changes which were added in mainline MySQL 5.1 through MySQL 5.1.15 (see *Note news-5-1-15::). *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * A single cluster can now support up to 255 API nodes, including MySQL servers acting as SQL nodes. See *Note mysql-cluster-limitations-exclusive-to-cluster::, for more information. *Bugs fixed:* * A memory leak could cause problems during a node or cluster shutdown or failure. (Bug #25997) * *Cluster API*: *Disk Data*: A delete and a read performed in the same operation could cause one or more data nodes to crash. This could occur when the operation affected more than 5 columns concurrently, or when one or more of the columns was of the *Note `VARCHAR': char. type and was stored on disk. (Bug #25794) * An element could sometimes be inserted twice into the hash table, causing a data node to crash. (Bug #25286)  File: manual.info, Node: mysql-cluster-news-5-1-14-ndb-6-1-0, Prev: mysql-cluster-news-5-1-15-ndb-6-1-1, Up: mysql-cluster-news-6-1 17.7.6.24 Changes in MySQL Cluster NDB 6.1.0 (5.1.14-ndb-6.1.0) (20 December 2006) .................................................................................. This is the first MySQL Cluster NDB 6.1 release, incorporating new features and bugfixes made for the *Note `NDBCLUSTER': mysql-cluster. storage engine made since branching from MySQL 5.1.14 standard (see *Note news-5-1-14::). MySQL Cluster NDB 6.1 no longer in development MySQL Cluster NDB 6.1 (formerly known as `MySQL Cluster Carrier Grade Edition 6.1.x') is no longer being developed or maintained; if you are using a MySQL Cluster NDB 6.1 release, you should consider upgrading to MySQL Cluster NDB 6.2 or 6.3. *Note*: Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Functionality added or changed:* * A new configuration parameter `MemReportFrequency' enables additional control of data node memory usage. Previously, only warnings at predetermined percentages of memory allocation were given; setting this parameter enables that behavior to be overridden. *Bugs fixed:* * When a data node was shut down using the management client `STOP' command, a connection event (`NDB_LE_Connected') was logged instead of a disconnection event (`NDB_LE_Disconnected'). (Bug #22773) * *Note `SELECT': select. statements with a *Note `BLOB': blob. or *Note `TEXT': blob. column in the selected column list and a `WHERE' condition including a primary key lookup on a *Note `VARCHAR': char. primary key produced empty result sets. (Bug #19956) * *Disk Data*: *Note `MEDIUMTEXT': blob. columns of Disk Data tables were stored in memory rather than on disk, even if the columns were not indexed. (Bug #25001) * *Disk Data*: Performing a node restart with a newly dropped Disk Data table could lead to failure of the node during the restart. (Bug #24917) * *Disk Data*: When restoring from backup a cluster containing any Disk Data tables with hidden primary keys, a node failure resulted which could lead to a crash of the cluster. (Bug #24166) * *Disk Data*: Repeated `CREATE', `DROP', or *Note `TRUNCATE TABLE': truncate-table. in various combinations with system restarts between these operations could lead to the eventual failure of a system restart. (Bug #21948) * *Disk Data*: Extents that should have been available for re-use following a *Note `DROP TABLE': drop-table. operation were not actually made available again until after the cluster had performed a local checkpoint. (Bug #17605) * *Cluster API*: Invoking the `NdbTransaction::execute()' method using execution type `Commit' and abort option `AO_IgnoreError' could lead to a crash of the transaction coordinator (`DBTC'). (Bug #25090) * *Cluster API*: A unique index lookup on a nonexistent tuple could lead to a data node timeout (error 4012). (Bug #25059) * *Cluster API*: When using the `NdbTransaction::execute()' method, a very long timeout (greater than 5 minutes) could result if the last data node being polled was disconnected from the cluster. (Bug #24949) * *Cluster API*: Due to an error in the computation of table fragment arrays, some transactions were not executed from the correct starting point. (Bug #24914) * Under certain rare circumstances, local checkpoints were not performed properly, leading to an inability to restart one or more data nodes. (Bug #24664)  File: manual.info, Node: mysql-cluster-news-series, Prev: mysql-cluster-news-6-1, Up: mysql-cluster-news 17.7.7 Release Series Changelogs: MySQL Cluster NDB 6.X and 7.X --------------------------------------------------------------- * Menu: * mysql-cluster-news-7-1-series:: Changes in the MySQL Cluster NDB 7.1 Series * mysql-cluster-news-7-0-series:: Changes in the MySQL Cluster NDB 7.0 Series * mysql-cluster-news-6-3-series:: Changes in the MySQL Cluster NDB 6.3 Series * mysql-cluster-news-6-2-series:: Changes in the MySQL Cluster NDB 6.2 Series * mysql-cluster-news-6-1-series:: Changes in the MySQL Cluster NDB 6.1 Series This section contains unified changelog information for each MySQL Cluster release series (NDB 6.1, NDB 6.2, NDB 6.3, and NDB 7.0). For changelogs covering individual MySQL Cluster NDB 6.X and MySQL Cluster NDB 7.X releases, see *Note mysql-cluster-news::. For general information about features added in MySQL Cluster NDB 6.X and 7.X, see *Note mysql-cluster-development::. An overview of features added in MySQL 5.1 not specific to MySQL Cluster can be found here: *Note mysql-nutshell::. For a complete list of all bugfixes and features changes made in MySQL 5.1 that are not specific to MySQL Cluster, see *Note news-5-1-x::.  File: manual.info, Node: mysql-cluster-news-7-1-series, Next: mysql-cluster-news-7-0-series, Prev: mysql-cluster-news-series, Up: mysql-cluster-news-series 17.7.7.1 Changes in the MySQL Cluster NDB 7.1 Series .................................................... This section contains unified change history highlights for all MySQL Cluster releases based on version 7.1 of the *Note `NDBCLUSTER': mysql-cluster. storage engine through MySQL Cluster NDB 7.1.16. Included are all changelog entries in the categories _MySQL Cluster_, _Disk Data_, and _Cluster API_. For an overview of features that were added in MySQL Cluster NDB 7.1, see *Note mysql-cluster-development-5-1-ndb-7-1::. * Changes in MySQL Cluster NDB 7.1.15 (5.1.56-ndb-7.1.15) * Changes in MySQL Cluster NDB 7.1.14 (5.1.56-ndb-7.1.14) * Changes in MySQL Cluster NDB 7.1.13 (5.1.56-ndb-7.1.13) * Changes in MySQL Cluster NDB 7.1.12 (5.1.51-ndb-7.1.12) * Changes in MySQL Cluster NDB 7.1.11 (5.1.51-ndb-7.1.11) * Changes in MySQL Cluster NDB 7.1.10 (5.1.51-ndb-7.1.10) * Changes in MySQL Cluster NDB 7.1.9 (5.1.51-ndb-7.1.9) * Changes in MySQL Cluster NDB 7.1.8 (5.1.47-ndb-7.1.8) * Changes in MySQL Cluster NDB 7.1.7 (5.1.47-ndb-7.1.7) * Changes in MySQL Cluster NDB 7.1.6 (5.1.47-ndb-7.1.6) * Changes in MySQL Cluster NDB 7.1.5 (5.1.47-ndb-7.1.5) * Changes in MySQL Cluster NDB 7.1.4 (5.1.44-ndb-7.1.4) * Changes in MySQL Cluster NDB 7.1.3 (5.1.44-ndb-7.1.3) * Changes in MySQL Cluster NDB 7.1.2 (5.1.41-ndb-7.1.2) * Changes in MySQL Cluster NDB 7.1.1 (5.1.41-ndb-7.1.1) * Changes in MySQL Cluster NDB 7.1.0 (5.1.39-ndb-7.1.0) *Changes in MySQL Cluster NDB 7.1.15 (5.1.56-ndb-7.1.15) * *Functionality added or changed:* * Added the `MaxDMLOperationsPerTransaction' data node configuration parameter, which can be used to limit the number of DML operations used by a transaction; if the transaction requires more than this many DML operations, the transaction is aborted. (Bug #12589613) *Bugs fixed:* * When global checkpoint indexes were written with no intervening end-of-file or megabyte border markers, this could sometimes lead to a situation in which the end of the redo log was mistakenly regarded as being between these GCIs, so that if the restart of a data node took place before the start of the next redo log was overwritten, the node encountered an `Error while reading the REDO log'. (Bug #12653993, Bug #61500) See also Bug #56961. * Restarting a *Note `mysqld': mysqld. during a rolling upgrade with data nodes running a mix of old and new versions of the MySQL Cluster software caused the *Note `mysqld': mysqld. to run in read-only mode. (Bug #12651364, Bug #61498) * Error reporting has been improved for cases in which API nodes are unable to connect due to apparent unavailability of node IDs. (Bug #12598398) * Error messages for `Failed to convert connection' transporter registration problems were inspecific. (Bug #12589691) * Under certain rare circumstances, a data node process could fail with Signal 11 during a restart. This was due to uninitialized variables in the `QMGR' kernel block. (Bug #12586190) * Multiple management servers were unable to detect one another until all nodes had fully started. As part of the fix for this issue, two new status values `RESUME' and `CONNECTED' can be reported for management nodes in the output of the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client `SHOW' command (see *Note mysql-cluster-mgm-client-commands::). Two corresponding status values `NDB_MGM_NODE_STATUS_RESUME' and `NDB_MGM_NODE_STATUS_CONNECTED' are also added to the list of possible values for an `ndb_mgm_node_status' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-node-status.html) data structure in the MGM API. (Bug #12352191, Bug #48301) * Handling of the `MaxNoOfTables' and `MaxNoOfAttributes' configuration parameters was not consistent in all parts of the *Note `NDB': mysql-cluster. kernel, and were only strictly enforced by the `DBDICT' and `SUMA' kernel blocks. This could lead to problems when tables could be created but not replicated. Now these parameters are treated by `SUMA' and `DBDICT' as suggested maximums rather than hard limits, as they are elsewhere in the *Note `NDB': mysql-cluster. kernel. (Bug #61684) * It was not possible to shut down a management node while one or more data nodes were stopped (for whatever reason). This issue was a regression introduced in MySQL Cluster NDB 7.0.24 and MySQL Cluster NDB 7.1.13. (Bug #61607) See also Bug #61147. * *Cluster API*: Applications that included the header file `ndb_logevent.h' could not be built using the Microsoft Visual Studio C compiler or the Oracle (Sun) Studio C compiler due to empty struct definitions. (Bug #12678971) * *Cluster API*: Within a transaction, after creating, executing, and closing a scan, calling `NdbTransaction::refresh()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndbtransaction-methods.html#ndb-ndbtransaction-refresh) after creating and executing but not closing a second scan caused the application to crash. (Bug #12646659) *Changes in MySQL Cluster NDB 7.1.14 (5.1.56-ndb-7.1.14) * *Bugs fixed:* * The internal `Ndb_getinaddr()' function has been rewritten to use `getaddrinfo()' instead of `my_gethostbyname_r()' (which is removed in a later version of the MySQL Server). (Bug #12542120) * *Note `mysql_upgrade': mysql-upgrade. failed when performing an online upgrade from MySQL Cluster NDB 7.1.8 or an earlier release to MySQL Cluster NDB 7.1.9 or later in which the SQL nodes were upgraded before the data nodes. This issue could occur during any online upgrade or downgrade where one or more *Note `ndbinfo': mysql-cluster-ndbinfo. tables had more, fewer, or differing columns between the two versions, and when the data nodes were not upgraded before the SQL nodes. For more information, see *Note mysql-cluster-upgrade-downgrade-compatibility-7.x::. (Bug #11885602, Bug #12581895, Bug #12581954) * Two unused test files in `storage/ndb/test/sql' contained incorrect versions of the GNU Lesser General Public License. The files and the directory containing them have been removed. (Bug #11810156) See also Bug #11810224. * Error 1302 gave the wrong error message (`Out of backup record'). This has been corrected to `A backup is already running'. (Bug #11793592) * When using two management servers, issuing in an *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client connected to one management server a `STOP' command for stopping the other management server caused Error 2002 (`Stop failed ... Send to process or receive failed.: Permanent error: Application error'), even though the `STOP' command actually succeeded, and the second *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. was shut down. (Bug #61147) * In *Note `ndbmtd': mysql-cluster-programs-ndbmtd, a node connection event is detected by a `CMVMI' thread which sends a `CONNECT_REP' signal to the `QMGR' kernel block. In a few isolated circumstances, a signal might be transfered to `QMGR' directly by the *Note `NDB': mysql-cluster. transporter before the `CONNECT_REP' signal actually arrived. This resulted in reports in the error log with status `Temporary error, restart node', and the message `Internal program error'. (Bug #61025) * Renaming a table having *Note `BLOB': blob. or *Note `TEXT': blob. columns (or both) to another database caused the SQL node to crash, and the table to become inaccessible afterwards. (Bug #60484) * Under heavy loads with many concurrent inserts, temporary failures in transactions could occur (and were misreported as being due to *Note `NDB': mysql-cluster. Error 899 `Rowid already allocated'). As part of the fix for this issue, *Note `NDB': mysql-cluster. Error 899 has been reclassified as an internal error, rather than as a temporary transaction error. (Bug #56051, Bug #11763354) * *Disk Data*: Accounting for `MaxNoOfOpenFiles' was incorrect with regard to to data files in MySQL Cluster Disk Data tablespaces. This could lead to a crash when `MaxNoOfOpenFiles' was exceeded. (Bug #12581213) *Changes in MySQL Cluster NDB 7.1.13 (5.1.56-ndb-7.1.13) * *Functionality added or changed:* * It is now possible to add data nodes online to a running MySQL Cluster without performing a rolling restart of the cluster or starting data node processes with the `--nowait-nodes' option. This can be done by setting `Nodegroup = 65536' in the `config.ini' file for any data nodes that should be started at a later time, when first starting the cluster. (It was possible to set `NodeGroup' to this value previously, but the management server failed to start.) As part of this fix, a new data node configuration parameter `StartNoNodeGroupTimeout' has been added. When the management server sees that there are data nodes with no node group (that is, nodes for which `Nodegroup = 65536'), it waits `StartNoNodeGroupTimeout' milliseconds before treating these nodes as though they were listed with the `--nowait-nodes' option, and proceeds to start. For more information, see *Note mysql-cluster-online-add-node::. (Bug #11766167, Bug #59213) * A `config_generation' column has been added to the *Note `nodes': mysql-cluster-ndbinfo-nodes. table of the *Note `ndbinfo': mysql-cluster-ndbinfo. database. By checking this column, it is now possible to determine which version or versions of the MySQL Cluster configuration file are in effect on the data nodes. This information can be especially useful when performing a rolling restart of the cluster in order to update its configuration. *Bugs fixed:* * *Cluster API*: A unique index operation is executed in two steps: a lookup on an index table, and an operation on the base table. When the operation on the base table failed, while being executed in a batch with other operations that succeeded, this could lead to a hanging execute, eventually timing out with Error 4012 (`Request ndbd time-out, maybe due to high load or communication problems'). (Bug #12315582) * *Cluster API*: A unique index operation is executed in two steps: a lookup on an index table, and an operation on the base table. When the operation on the base table failed, while being executed in a batch with other operations that succeeded, this could lead to a hanging execute, eventually timing out with Error 4012 (`Request ndbd time-out, maybe due to high load or communication problems'). (Bug #12315582) * A memory leak in `LGMAN', that leaked 8 bytes of log buffer memory per 32k written, was introduced in MySQL Cluster NDB 7.0.9, effecting all MySQL Cluster NDB 7.1 releases as well as MySQL Cluster NDB 7.0.9 and later MySQL Cluster NDB 7.0 releases. (For example, when 128 MB log buffer memory was used, it was exhausted after writing 512 GB to the undo log.) This led to a GCP stop and data node failure. (Bug #60946) This regression was introduced by Bug #47966. * When using *Note `ndbmtd': mysql-cluster-programs-ndbmtd, a MySQL Cluster configured with 32 data nodes failed to start correctly. (Bug #60943) * When performing a TUP scan with locks in parallel, and with a highly concurrent load of inserts and deletions, the scan could sometimes fail to notice that a record had moved while waiting to acquire a lock on it, and so read the wrong record. During node recovery, this could lead to a crash of a node that was copying data to the node being started, and a possible forced shutdown of the cluster. * *Cluster API*: Performing interpreted operations using a unique index did not work correctly, because the interpret bit was kept when sending the lookup to the index table. *Changes in MySQL Cluster NDB 7.1.12 (5.1.51-ndb-7.1.12) * *Functionality added or changed:* * Improved scaling of ordered index scans performance by removing a hard-coded limit (`MAX_PARALLEL_INDEX_SCANS_PER_FRAG') and making the number of `TUP' or `TUX' scans per fragment configurable by adding the `MaxParallelScansPerFragment' data node configuration parameter. (Bug #11769048) *Bugs fixed:* * *Important Change*: Formerly, the `--ndb-cluster-connection-pool' server option set a status variable as well as a system variable. The status variable has been removed as redundant. (Bug #60119) * A scan with a pushed condition (filter) using the `CommittedRead' lock mode could hang for a short interval when it was aborted when just as it had decided to send a batch. (Bug #11932525) * When aborting a multi-read range scan exactly as it was changing ranges in the local query handler, LQH could fail to detect it, leaving the scan hanging. (Bug #11929643) * Schema distribution did not take place for tables converted from another storage engine to *Note `NDB': mysql-cluster. using *Note `ALTER TABLE': alter-table.; this meant that such tables were not always visible to all SQL nodes attached to the cluster. (Bug #11894966) * A GCI value inserted by *Note `ndb_restore': mysql-cluster-programs-ndb-restore. `--restore_epoch' into the `ndb_apply_status' table was actually 1 less than the correct value. (Bug #11885852) * *Disk Data*: Limits imposed by the size of `SharedGlobalMemory' were not always enforced consistently with regard to Disk Data undo buffers and log files. This could sometimes cause a *Note `CREATE LOGFILE GROUP': create-logfile-group. or *Note `ALTER LOGFILE GROUP': alter-logfile-group. statement to fail for no apparent reason, or cause the log file group specified by `InitialLogFileGroup' not to be created when starting the cluster. (Bug #57317) *Changes in MySQL Cluster NDB 7.1.11 (5.1.51-ndb-7.1.11) * *Functionality added or changed:* * *Disk Data*: The *Note `INFORMATION_SCHEMA.TABLES': tables-table. table now provides disk usage as well as memory usage information for Disk Data tables. Also, *Note `INFORMATION_SCHEMA.PARTITIONS': partitions-table, formerly did not show any statistics for *Note `NDB': mysql-cluster. tables. Now the `TABLE_ROWS', `AVG_ROW_LENGTH', `DATA_LENGTH', `MAX_DATA_LENGTH', and `DATA_FREE' columns contain correct information for the table's partitions. * *Disk Data*: The *Note `INFORMATION_SCHEMA.TABLES': tables-table. table now provides disk usage as well as memory usage information for Disk Data tables. Also, *Note `INFORMATION_SCHEMA.PARTITIONS': partitions-table, formerly did not show any statistics for *Note `NDB': mysql-cluster. tables. Now the `TABLE_ROWS', `AVG_ROW_LENGTH', `DATA_LENGTH', `MAX_DATA_LENGTH', and `DATA_FREE' columns contain correct information for the table's partitions. * A new `--rewrite-database' option is added for *Note `ndb_restore': mysql-cluster-programs-ndb-restore, which makes it possible to restore to a database having a different name from that of the database in the backup. For more information, see *Note mysql-cluster-programs-ndb-restore::. (Bug #54327) * Added the `--lossy-conversions' option for *Note `ndb_restore': mysql-cluster-programs-ndb-restore, which makes it possible to enable attribute demotion when restoring a MySQL Cluster from an *Note `NDB': mysql-cluster. native backup. For additional information about type conversions currently supported by MySQL Cluster for attribute promotion and demotion, see *Note replication-features-different-data-types::. * Made it possible to enable multi-threaded building of ordered indexes during initial restarts, using the new `TwoPassInitialNodeRestartCopy' data node configuration parameter. *Bugs fixed:* * This issue affects all previous MySQL Cluster NDB 7.1 releases. (Bug #60045) * *Note `ndb_restore `--rebuild-indexes'': mysql-cluster-programs-ndb-restore. caused multi-threaded index building to occur on the master node only. (Bug #59920) * Successive queries on the *Note `counters': mysql-cluster-ndbinfo-counters. table from the same SQL node returned unchanging results. To fix this issue, and to prevent similar issues from occurring in the future, *Note `ndbinfo': mysql-cluster-ndbinfo. tables are now excluded from the query cache. (Bug #59831) * When a *Note `CREATE TABLE': create-table. statement failed due to *Note `NDB': mysql-cluster. error 1224 (`Too many fragments'), it was not possible to create the table afterward unless either it had no ordered indexes, or a *Note `DROP TABLE': drop-table. statement was issued first, even if the subsequent *Note `CREATE TABLE': create-table. was valid and should otherwise have succeeded. (Bug #59756) See also Bug #59751. * When attempting to create a table on a MySQL Cluster with many standby data nodes (setting `Nodegroup=65536' in `config.ini' for the nodes that should wait, starting the nodes that should start immediately with the `--nowait-nodes' option, and using the *Note `CREATE TABLE': create-table. statement's `MAX_ROWS' option), *Note `mysqld': mysqld. miscalculated the number of fragments to use. This caused the *Note `CREATE TABLE': create-table. to fail. *Note*: The *Note `CREATE TABLE': create-table. failure caused by this issue in turn prevented any further attempts to create the table, even if the table structure was simplified or changed in such a way that the attempt should have succeeded. This `ghosting' issue is handled in BUG#59756. (Bug #59751) * *Note `NDB': mysql-cluster. sometimes treated a simple (not unique) ordered index as unique. (Bug #59519) * The logic used in determining whether to collapse a range to a simple equality was faulty. In certain cases, this could cause *Note `NDB': mysql-cluster. to treat a range as if it were a primary key lookup when determining the query plan to be used. Although this did not affect the actual result returned by the query, it could in such cases result in inefficient execution of queries due to the use of an inappropriate query plan. (Bug #59517) * When a query used multiple references to or instances of the same physical tables, *Note `NDB': mysql-cluster. failed to recognize these multiple instances as different tables; in such a case, *Note `NDB': mysql-cluster. could incorrectly use condition pushdown on a condition referring to these other instances to be pushed to the data nodes, even though the condition should have been rejected as unpushable, leading to invalid results. (Bug #58791) * *Cluster API*: When calling `NdbEventOperation::execute()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndbeventoperation-methods.html#ndb-ndbeventoperation-execute) during a node restart, it was possible to get a spurious error 711 (`System busy with node restart, schema operations not allowed when a node is starting'). (Bug #59723) * *Cluster API*: When an NDBAPI client application was waiting for more scan results after calling `NdbScanOperation::nextResult()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndbscanoperation-methods.html#ndb-ndbscanoperation-nextresult), the calling thread sometimes woke up even if no new batches for any fragment had arrived, which was unnecessary, and which could have a negative impact on the application's performance. (Bug #52298) *Changes in MySQL Cluster NDB 7.1.10 (5.1.51-ndb-7.1.10) * *Functionality added or changed:* * *Important Change*: The following changes have been made with regard to the `TimeBetweenEpochsTimeout' data node configuration parameter: * The maximum possible value for this parameter has been increased from 32000 milliseconds to 256000 milliseconds. * Setting this parameter to zero now has the effect of disabling GCP stops caused by save timeouts, commit timeouts, or both. * The current value of this parameter and a warning are written to the cluster log whenever a GCP save takes longer than 1 minute or a GCP commit takes longer than 10 seconds. For more information, see *Note mysql-cluster-ndbd-definition-gcp-stop-errors::. (Bug #58383) * Added the `--skip-broken-objects' option for *Note `ndb_restore': mysql-cluster-programs-ndb-restore. This option causes *Note `ndb_restore': mysql-cluster-programs-ndb-restore. to ignore tables corrupted due to missing blob parts tables, and to continue reading from the backup file and restoring the remaining tables. (Bug #54613) See also Bug #51652. * Made it possible to exercise more direct control over handling of timeouts occurring when trying to flush redo logs to disk using two new data node configuration parameters `RedoOverCommitCounter' and `RedoOverCommitLimit', as well as the new API node configuration parameter `DefaultOperationRedoProblemAction', all added in this release. Now, when such timeouts occur more than a specified number of times for the flushing of a given redo log, any transactions that were to be written are instead aborted, and the operations contained in those transactions can be either re-tried or themselves aborted. For more information, see *Note mysql-cluster-redo-over-commit-handling::. * *Cluster API*: It is now possible to stop or restart a node even while other nodes are starting, using the MGM API `ndb_mgm_stop4()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-stop4.html) or `ndb_mgm_restart4()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-restart4.html) function, respectively, with the FORCE parameter set to 1. (Bug #58451) See also Bug #58319. *Bugs fixed:* * *Cluster API*: In some circumstances, very large *Note `BLOB': blob. read and write operations in MySQL Cluster applications can cause excessive resource usage and even exhaustion of memory. To fix this issue and to provide increased stability when performing such operations, it is now possible to set limits on the volume of *Note `BLOB': blob. data to be read or written within a given transaction in such a way that when these limits are exceeded, the current transaction implicitly executes any accumulated operations. This avoids an excessive buildup of pending data which can result in resource exhaustion in the NDB kernel. The limits on the amount of data to be read and on the amount of data to be written before this execution takes place can be configured separately. (In other words, it is now possible in MySQL Cluster to specify read batching and write batching that is specific to *Note `BLOB': blob. data.) These limits can be configured either on the NDB API level, or in the MySQL Server. On the NDB API level, four new methods are added to the `NdbTransaction' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndbtransaction.html#ndb-ndbtransaction) object. `getMaxPendingBlobReadBytes()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndbtransaction-methods.html#ndb-ndbtransaction-getmaxpendingblobreadbytes) and `setMaxPendingBlobReadBytes()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndbtransaction-methods.html#ndb-ndbtransaction-setmaxpendingblobreadbytes) can be used to get and to set, respectively, the maximum amount of *Note `BLOB': blob. data to be read that accumulates before this implicit execution is triggered. `getMaxPendingBlobWriteBytes()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndbtransaction-methods.html#ndb-ndbtransaction-getmaxpendingblobwritebytes) and `setMaxPendingBlobWriteBytes()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndbtransaction-methods.html#ndb-ndbtransaction-setmaxpendingblobwritebytes) can be used to get and to set, respectively, the maximum volume of *Note `BLOB': blob. data to be written that accumulates before implicit execution occurs. For the MySQL server, two new options are added. The `--ndb-blob-read-batch-bytes' option sets a limit on the amount of pending *Note `BLOB': blob. data to be read before triggering implicit execution, and the `--ndb-blob-write-batch-bytes' option controls the amount of pending *Note `BLOB': blob. data to be written. These limits can also be set using the *Note `mysqld': mysqld. configuration file, or read and set within the *Note `mysql': mysql. client and other MySQL client applications using the corresponding server system variables. (Bug #59113) * *Cluster API*: In some circumstances, very large *Note `BLOB': blob. read and write operations in MySQL Cluster applications can cause excessive resource usage and even exhaustion of memory. To fix this issue and to provide increased stability when performing such operations, it is now possible to set limits on the volume of *Note `BLOB': blob. data to be read or written within a given transaction in such a way that when these limits are exceeded, the current transaction implicitly executes any accumulated operations. This avoids an excessive buildup of pending data which can result in resource exhaustion in the NDB kernel. The limits on the amount of data to be read and on the amount of data to be written before this execution takes place can be configured separately. (In other words, it is now possible in MySQL Cluster to specify read batching and write batching that is specific to *Note `BLOB': blob. data.) These limits can be configured either on the NDB API level, or in the MySQL Server. On the NDB API level, four new methods are added to the `NdbTransaction' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndbtransaction.html#ndb-ndbtransaction) object. `getMaxPendingBlobReadBytes()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndbtransaction-methods.html#ndb-ndbtransaction-getmaxpendingblobreadbytes) and `setMaxPendingBlobReadBytes()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndbtransaction-methods.html#ndb-ndbtransaction-setmaxpendingblobreadbytes) can be used to get and to set, respectively, the maximum amount of *Note `BLOB': blob. data to be read that accumulates before this implicit execution is triggered. `getMaxPendingBlobWriteBytes()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndbtransaction-methods.html#ndb-ndbtransaction-getmaxpendingblobwritebytes) and `setMaxPendingBlobWriteBytes()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndbtransaction-methods.html#ndb-ndbtransaction-setmaxpendingblobwritebytes) can be used to get and to set, respectively, the maximum volume of *Note `BLOB': blob. data to be written that accumulates before implicit execution occurs. For the MySQL server, two new options are added. The `--ndb-blob-read-batch-bytes' option sets a limit on the amount of pending *Note `BLOB': blob. data to be read before triggering implicit execution, and the `--ndb-blob-write-batch-bytes' option controls the amount of pending *Note `BLOB': blob. data to be written. These limits can also be set using the *Note `mysqld': mysqld. configuration file, or read and set within the *Note `mysql': mysql. client and other MySQL client applications using the corresponding server system variables. (Bug #59113) * Two related problems could occur with read-committed scans made in parallel with transactions combining multiple (concurrent) operations: 1. When committing a multiple-operation transaction that contained concurrent insert and update operations on the same record, the commit arrived first for the insert and then for the update. If a read-committed scan arrived between these operations, it could thus read incorrect data; in addition, if the scan read variable-size data, it could cause the data node to fail. 2. When rolling back a multiple-operation transaction having concurrent delete and insert operations on the same record, the abort arrived first for the delete operation, and then for the insert. If a read-committed scan arrived between the delete and the insert, it could incorrectly assume that the record should not be returned (in other words, the scan treated the insert as though it had not yet been committed). (Bug #59496) * On Windows platforms, issuing a `SHUTDOWN' command in the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client caused management processes that had been started with the `--nodaemon' option to exit abnormally. (Bug #59437) * A row insert or update followed by a delete operation on the same row within the same transaction could in some cases lead to a buffer overflow. (Bug #59242) See also Bug #56524. This regression was introduced by Bug #35208. * Data nodes configured with very large amounts (multiple gigabytes) of `DiskPageBufferMemory' failed during startup with NDB error 2334 (`Job buffer congestion'). (Bug #58945) See also Bug #47984. * The `FAIL_REP' signal, used inside the NDB kernel to declare that a node has failed, now includes the node ID of the node that detected the failure. This information can be useful in debugging. (Bug #58904) * When executing a full table scan caused by a `WHERE' condition using `UNIQUE_KEY IS NULL' in combination with a join, *Note `NDB': mysql-cluster. failed to close the scan. (Bug #58750) See also Bug #57481. * In some circumstances, an SQL trigger on an *Note `NDB': mysql-cluster. table could read stale data. (Bug #58538) * During a node takeover, it was possible in some circumstances for one of the remaining nodes to send an extra transaction confirmation (`LQH_TRANSCONF') signal to the `DBTC' kernel block, conceivably leading to a crash of the data node trying to take over as the new transaction coordinator. (Bug #58453) * A query having multiple predicates joined by `OR' in the `WHERE' clause and which used the `sort_union' access method (as shown using *Note `EXPLAIN': explain.) could return duplicate rows. (Bug #58280) * Trying to drop an index while it was being used to perform scan updates caused data nodes to crash. (Bug #58277, Bug #57057) * When handling failures of multiple data nodes, an error in the construction of internal signals could cause the cluster's remaining nodes to crash. This issue was most likely to affect clusters with large numbers of data nodes. (Bug #58240) * The functions `strncasecmp' and `strcasecmp' were declared in `ndb_global.h' but never defined or used. The declarations have been removed. (Bug #58204) * Some queries of the form *Note `SELECT ... WHERE COLUMN IN (SUBQUERY)': select. against an *Note `NDB': mysql-cluster. table could cause *Note `mysqld': mysqld. to hang in an endless loop. (Bug #58163) * The number of rows affected by a statement that used a `WHERE' clause having an `IN' condition with a value list containing a great many elements, and that deleted or updated enough rows such that *Note `NDB': mysql-cluster. processed them in batches, was not computed or reported correctly. (Bug #58040) * MySQL Cluster failed to compile correctly on FreeBSD 8.1 due to misplaced `#include' statements. (Bug #58034) * A query using `BETWEEN' as part of a pushed-down `WHERE' condition could cause mysqld to hang or crash. (Bug #57735) * Data nodes no longer allocated all memory prior to being ready to exchange heartbeat and other messages with management nodes, as in NDB 6.3 and earlier versions of MySQL Cluster. This caused problems when data nodes configured with large amounts of memory failed to show as connected or showed as being in the wrong start phase in the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client even after making their initial connections to and fetching their configuration data from the management server. With this fix, data nodes now allocate all memory as they did in earlier MySQL Cluster versions. (Bug #57568) * In some circumstances, it was possible for *Note `mysqld': mysqld. to begin a new multi-range read scan without having closed a previous one. This could lead to exhaustion of all scan operation objects, transaction objects, or lock objects (or some combination of these) in *Note `NDB': mysql-cluster, causing queries to fail with such errors as `Lock wait timeout exceeded' or `Connect failure - out of connection objects'. (Bug #57481) See also Bug #58750. * Queries using `COLUMN IS' [`NOT'] `NULL' on a table with a unique index created with `USING HASH' on COLUMN always returned an empty result. (Bug #57032) * With `engine_condition_pushdown' enabled, a query using `LIKE' on an *Note `ENUM': enum. column of an *Note `NDB': mysql-cluster. table failed to return any results. This issue is resolved by disabling `engine_condition_pushdown' when performing such queries. (Bug #53360) * When a slash character (`/') was used as part of the name of an index on an *Note `NDB': mysql-cluster. table, attempting to execute a *Note `TRUNCATE TABLE': truncate-table. statement on the table failed with the error `Index not found', and the table was rendered unusable. (Bug #38914) * *Disk Data*: *Partitioning*: When using multi-threaded data nodes, an *Note `NDB': mysql-cluster. table created with a very large value for the `MAX_ROWS' option could--if this table was dropped and a new table with fewer partitions, but having the same table ID, was created--cause *Note `ndbmtd': mysql-cluster-programs-ndbmtd. to crash when performing a system restart. This was because the server attempted to examine each partition whether or not it actually existed. This issue is the same as that reported in Bug#45154, except that the current issue is specific to *Note `ndbmtd': mysql-cluster-programs-ndbmtd. instead of *Note `ndbd': mysql-cluster-programs-ndbd. (Bug #58638) * *Disk Data*: In certain cases, a race condition could occur when *Note `DROP LOGFILE GROUP': drop-logfile-group. removed the logfile group while a read or write of one of the effected files was in progress, which in turn could lead to a crash of the data node. (Bug #59502) * *Disk Data*: A race condition could sometimes be created when *Note `DROP TABLESPACE': drop-tablespace. was run concurrently with a local checkpoint; this could in turn lead to a crash of the data node. (Bug #59501) * *Disk Data*: Performing what should have been an online drop of a multi-column index was actually performed offline. (Bug #55618) * *Disk Data*: When at least one data node was not running, queries against the *Note `INFORMATION_SCHEMA.FILES': files-table. table took an excessive length of time to complete because the MySQL server waited for responses from any stopped nodes to time out. Now, in such cases, MySQL does not attempt to contact nodes which are not known to be running. (Bug #54199) * *Cluster API*: It was not possible to obtain the status of nodes accurately after an attempt to stop a data node using `ndb_mgm_stop()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-stop.html) failed without returning an error. (Bug #58319) * *Cluster API*: Attempting to read the same value (using `getValue()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndboperation-methods.html#ndb-ndboperation-getvalue)) more than 9000 times within the same transaction caused the transaction to hang when executed. Now when more reads are performed in this way than can be accommodated in a single transaction, the call to `execute()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndbtransaction-methods.html#ndb-ndbtransaction-execute) fails with a suitable error. (Bug #58110) *Changes in MySQL Cluster NDB 7.1.9 (5.1.51-ndb-7.1.9) * *Functionality added or changed:* * *Important Change*: *InnoDB Storage Engine*: Building the MySQL Server with the *Note `InnoDB': innodb-storage-engine. plugin is now supported when building MySQL Cluster. For more information, see *Note mysql-cluster-installation::. (Bug #54912) See also Bug #58283. * *Important Change*: *Note `ndbd': mysql-cluster-programs-ndbd. now bypasses use of Non-Uniform Memory Access support on Linux hosts by default. If your system supports NUMA, you can enable it and override *Note `ndbd': mysql-cluster-programs-ndbd. use of interleaving by setting the `Numa' data node configuration parameter which is added in this release. See Defining Data Nodes: Realtime Performance Parameters, for more information. (Bug #57807) * A new *Note `diskpagebuffer': mysql-cluster-ndbinfo-diskpagebuffer. table, providing statistics on disk page buffer usage by Disk Data tables, is added to the *Note `ndbinfo': mysql-cluster-ndbinfo. information database. These statistics can be used to monitor performance of reads and writes on Disk Data tables, and to assist in the tuning of related parameters such as `DiskPageBufferMemory'. *Bugs fixed:* * *Packaging*: MySQL Cluster RPM distributions did not include a `shared-compat' RPM for the MySQL Server, which meant that MySQL applications depending on `libmysqlclient.so.15' (MySQL 5.0 and earlier) no longer worked. (Bug #38596) * On Windows, the angel process which monitors and (when necessary) restarts the data node process failed to spawn a new worker in some circumstances where the arguments vector contained extra items placed at its beginning. This could occur when the path to *Note `ndbd.exe': mysql-cluster-programs-ndbd. or *Note `ndbmtd.exe': mysql-cluster-programs-ndbmtd. contained one or more spaces. (Bug #57949) * The disconnection of an API or management node due to missed heartbeats led to a race condition which could cause data nodes to crash. (Bug #57946) * The method for calculating table schema versions used by schema transactions did not follow the established rules for recording schemas used in the `P0.SchemaLog' file. (Bug #57897) See also Bug #57896. * The `LQHKEYREQ' request message used by the local query handler when checking the major schema version of a table, being only 16 bits wide, could cause this check to fail with an `Invalid schema version' error (*Note `NDB': mysql-cluster. error code 1227). This issue occurred after creating and dropping (and re-creating) the same table 65537 times, then trying to insert rows into the table. (Bug #57896) See also Bug #57897. * Data nodes compiled with `gcc' 4.5 or higher crashed during startup. (Bug #57761) * Transient errors during a local checkpoint were not retried, leading to a crash of the data node. Now when such errors occur, they are retried up to 10 times if necessary. (Bug #57650) * *Note `ndb_restore': mysql-cluster-programs-ndb-restore. now retries failed transactions when replaying log entries, just as it does when restoring data. (Bug #57618) * The `SUMA' kernel block has a 10-element ring buffer for storing out-of-order `SUB_GCP_COMPLETE_REP' signals received from the local query handlers when global checkpoints are completed. In some cases, exceeding the ring buffer capacity on all nodes of a node group at the same time caused the node group to fail with an assertion. (Bug #57563) * During a GCP takeover, it was possible for one of the data nodes not to receive a `SUB_GCP_COMPLETE_REP' signal, with the result that it would report itself as `GCP_COMMITTING' while the other data nodes reported `GCP_PREPARING'. (Bug #57522) * Specifying a *Note `WHERE': select. clause of the form `RANGE1 OR RANGE2' when selecting from an *Note `NDB': mysql-cluster. table having a primary key on multiple columns could result in Error 4259 `Invalid set of range scan bounds' if RANGE2 started exactly where RANGE1 ended and the primary key definition declared the columns in a different order relative to the order in the table's column list. (Such a query should simply return all rows in the table, since any expression `VALUE < CONSTANT OR VALUE >= CONSTANT' is always true.) Example Suppose `t' is an *Note `NDB': mysql-cluster. table defined by the following *Note `CREATE TABLE': create-table. statement: CREATE TABLE t (a, b, PRIMARY KEY (b, a)) ENGINE NDB; This issue could then be triggered by a query such as this one: SELECT * FROM t WHERE b < 8 OR b >= 8; In addition, the order of the ranges in the `WHERE' clause was significant; the issue was not triggered, for example, by the query *Note `SELECT * FROM t WHERE b <= 8 OR b > 8': select. (Bug #57396) * A number of cluster log warning messages relating to deprecated configuration parameters contained spelling, formatting, and other errors. (Bug #57381) * The `MAX_ROWS' option for *Note `CREATE TABLE': create-table. was ignored, which meant that it was not possible to enable multi-threaded building of indexes. (Bug #57360) * A GCP stop is detected using 2 parameters which determine the maximum time that a global checkpoint or epoch can go unchanged; one of these controls this timeout for GCPs and one controls the timeout for epochs. Suppose the cluster is configured such that `TimeBetweenEpochsTimeout' is 100 ms but `HeartbeatIntervalDbDb' is 1500 ms. A node failure can be signalled after 4 missed heartbeats--in this case, 6000 ms. However, this would exceed `TimeBetweenEpochsTimeout', causing false detection of a GCP. To prevent this from happening, the configured value for `TimeBetweenEpochsTimeout' is automatically adjusted, based on the values of `HeartbeatIntervalDbDb' and `ArbitrationTimeout'. The current issue arose when the automatic adjustment routine did not correctly take into consideration the fact that, during cascading node-failures, several intervals of length `4 * (HeartbeatIntervalDBDB + ArbitrationTimeout)' may elapse before all node failures have internally been resolved. This could cause false GCP detection in the event of a cascading node failure. (Bug #57322) * Successive `CREATE NODEGROUP' and `DROP NODEGROUP' commands could cause *Note `mysqld': mysqld. processes to crash. (Bug #57164) * Queries using `WHERE VARCHAR_PK_COLUMN LIKE 'PATTERN%'' or `WHERE VARCHAR_PK_COLUMN LIKE 'PATTERN_'' against an *Note `NDB': mysql-cluster. table having a *Note `VARCHAR': char. column as its primary key failed to return all matching rows. (Bug #56853) * Aborting a native `NDB' backup in the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client using the `ABORT BACKUP' command did not work correctly when using *Note `ndbmtd': mysql-cluster-programs-ndbmtd, in some cases leading to a crash of the cluster. (Bug #56285) * When a data node angel process failed to fork off a new worker process (to replace one that had failed), the failure was not handled. This meant that the angel process either transformed itself into a worker process, or itself failed. In the first case, the data node continued to run, but there was no longer any angel to restart it in the event of failure, even with `StopOnError' set to 0. (Bug #53456) * *Disk Data*: When performing online DDL on Disk Data tables, scans and moving of the relevant tuples were done in more or less random order. This fix causes these scans to be done in the order of the tuples, which should improve performance of such operations due to the more sequential ordering of the scans. (Bug #57848) See also Bug #57827. * *Disk Data*: Adding unique indexes to *Note `NDB': mysql-cluster. Disk Data tables could take an extremely long time. This was particularly noticeable when using *Note `ndb_restore `--rebuild-indexes'': mysql-cluster-programs-ndb-restore. (Bug #57827) * *Cluster API*: An application dropping a table at the same time that another application tried to set up a replication event on the same table could lead to a crash of the data node. The same issue could sometimes cause `NdbEventOperation::execute()' to hang. (Bug #57886) * *Cluster API*: An NDB API client program under load could abort with an assertion error in `TransporterFacade::remove_from_cond_wait_queue'. (Bug #51775) See also Bug #32708. *Changes in MySQL Cluster NDB 7.1.8 (5.1.47-ndb-7.1.8) * *Functionality added or changed:* * *Note `mysqldump': mysqldump. as supplied with MySQL Cluster now has an `--add-drop-trigger' option which adds a *Note `DROP TRIGGER IF EXISTS': drop-trigger. statement before each dumped trigger definition. (Bug #55691) See also Bug #34325, Bug #11747863. * It is now possible using the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. management client or the MGM API to force a data node shutdown or restart even if this would force the shutdown or restart of the entire cluster. In the management client, this is implemented through the addition of the `-f' (force) option to the `STOP' and `RESTART' commands. For more information, see *Note mysql-cluster-mgm-client-commands::. The MGM API also adds two new methods for forcing such a node shutdown or restart; see `ndb_mgm_stop4()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-stop4.html), and `ndb_mgm_restart4()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-restart4.html), for more information about these methods. (Bug #54226) * *Cluster API*: The MGM API function `ndb_mgm_get_version()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-get-version.html), which was previously internal, has now been moved to the public API. This function can be used to get `NDB' storage engine and other version information from the management server. (Bug #51310) See also Bug #51273. *Bugs fixed:* * At startup, an *Note `ndbd': mysql-cluster-programs-ndbd. or *Note `ndbmtd': mysql-cluster-programs-ndbmtd. process creates directories for its file system without checking to see whether they already exist. Portability code added in MySQL Cluster NDB 7.0.18 and MySQL Cluster NDB 7.1.7 did not account for this fact, printing a spurious error message when a directory to be created already existed. This unneeded printout has been removed. (Bug #57087) * A data node can be shut down having completed and synchronized a given GCI X, while having written a great many log records belonging to the next GCI X + 1, as part of normal operations. However, when starting, completing, and synchronizing GCI X + 1, then the log records from original start must not be read. To make sure that this does not happen, the REDO log reader finds the last GCI to restore, scans forward from that point, and erases any log records that were not (and should never be) used. The current issue occurred because this scan stopped immediately as soon as it encountered an empty page. This was problematic because the REDO log is divided into several files; thus, it could be that there were log records in the beginning of the next file, even if the end of the previous file was empty. These log records were never invalidated; following a start or restart, they could be reused, leading to a corrupt REDO log. (Bug #56961) * An error in program flow in `ndbd.cpp' could result in data node shutdown routines being called multiple times. (Bug #56890) * Under certain rare conditions, attempting to start more than one *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. process simultaneously using the `--reload' option caused a race condition such that none of the *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. processes could start. (Bug #56844) * When distributing *Note `CREATE TABLE': create-table. and *Note `DROP TABLE': drop-table. operations among several SQL nodes attached to a MySQL Cluster. the `LOCK_OPEN' lock normally protecting *Note `mysqld': mysqld.'s internal table list is released so that other queries or DML statements are not blocked. However, to make sure that other DDL is not executed simultaneously, a global schema lock (implemented as a row-level lock by `NDB') is used, such that all operations that can modify the state of the *Note `mysqld': mysqld. internal table list also need to acquire this global schema lock. The *Note `SHOW TABLE STATUS': show-table-status. statement did not acquire this lock. (Bug #56841) * In certain cases, *Note `DROP DATABASE': drop-database. could sometimes leave behind a cached table object, which caused problems with subsequent DDL operations. (Bug #56840) * Memory pages used for `DataMemory', once assigned to ordered indexes, were not ever freed, even after any rows that belonged to the corresponding indexes had been deleted. (Bug #56829) * MySQL Cluster stores, for each row in each `NDB' table, a Global Checkpoint Index (GCI) which identifies the last committed transaction that modified the row. As such, a GCI can be thought of as a coarse-grained row version. Due to changes in the format used by `NDB' to store local checkpoints (LCPs) in MySQL Cluster NDB 6.3.11, it could happen that, following cluster shutdown and subsequent recovery, the GCI values for some rows could be changed unnecessarily; this could possibly, over the course of many node or system restarts (or both), lead to an inconsistent database. (Bug #56770) * When multiple SQL nodes were connected to the cluster and one of them stopped in the middle of a DDL operation, the *Note `mysqld': mysqld. process issuing the DDL timed out with the error `distributing TBL_NAME timed out. Ignoring'. (Bug #56763) * An online *Note `ALTER TABLE ... ADD COLUMN': alter-table. operation that changed the table schema such that the number of 32-bit words used for the bitmask allocated to each DML operation increased during a transaction in DML which was performed prior to DDL which was followed by either another DML operation or--if using replication--a commit, led to data node failure. This was because the data node did not take into account that the bitmask for the before-image was smaller than the current bitmask, which caused the node to crash. (Bug #56524) * On Windows, a data node refused to start in some cases unless the *Note `ndbd.exe': mysql-cluster-programs-ndbd. executable was invoked using an absolute rather than a relative path. (Bug #56257) * The text file `cluster_change_hist.txt' containing old MySQL Cluster changelog information was no longer being maintained, and so has been removed from the tree. (Bug #56116) * The failure of a data node during some scans could cause other data nodes to fail. (Bug #54945) * Exhausting the number of available commit-ack markers (controlled by the `MaxNoOfConcurrentTransactions' parameter) led to a data node crash. (Bug #54944) * When running a *Note `SELECT': select. on an *Note `NDB': mysql-cluster. table with *Note `BLOB': blob. or *Note `TEXT': blob. columns, memory was allocated for the columns but was not freed until the end of the *Note `SELECT': select. This could cause problems with excessive memory usage when dumping (using for example *Note `mysqldump': mysqldump.) tables with such columns and having many rows, large column values, or both. (Bug #52313) See also Bug #56488, Bug #50310. * *Cluster API*: The MGM API functions `ndb_mgm_stop()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-stop.html) and `ndb_mgm_restart()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-restart.html) set the error code and message without first checking whether the management server handle was `NULL', which could lead to fatal errors in MGM API applications that depended on these functions. (Bug #57089) * *Cluster API*: The MGM API function `ndb_mgm_get_version()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-get-version.html) did not set the error message before returning with an error. With this fix, it is now possible to call `ndb_mgm_get_latest_error()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-get-latest-error.html) after a failed call to this function such that `ndb_mgm_get_latest_error()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-get-latest-error.html) returns an error number and error message, as expected of MGM API calls. (Bug #57088) *Changes in MySQL Cluster NDB 7.1.7 (5.1.47-ndb-7.1.7) * *Functionality added or changed:* * *Important Change*: More finely-grained control over restart-on-failure behavior is provided with two new data node configuration parameters `MaxStartFailRetries' and `StartFailRetryDelay'. `MaxStartFailRetries' limits the total number of retries made before giving up on starting the data node; `StartFailRetryDelay' sets the number of seconds between retry attempts. These parameters are used only if `StopOnError' is set to 0. For more information, see *Note mysql-cluster-ndbd-definition::. (Bug #54341) *Bugs fixed:* * *Important Change*: It is no longer possible to make a dump of the *Note `ndbinfo': mysql-cluster-ndbinfo. database using *Note `mysqldump': mysqldump. (Bug #54316) * *Note `ndb_restore': mysql-cluster-programs-ndb-restore. always reported 0 for the `GCPStop' (end point of the backup). Now it provides useful binary log position and epoch information. (Bug #56298) * The `LockExecuteThreadToCPU' configuration parameter was not handled correctly for CPU ID values greater than 255. (Bug #56185) * Following a failure of the master data node, the new master sometimes experienced a race condition which caused the node to terminate with a GcpStop error. (Bug #56044) * Trying to create a table having a *Note `BLOB': blob. or *Note `TEXT': blob. column with `DEFAULT ''' failed with the error `Illegal null attribute'. (An empty default is allowed and ignored by *Note `MyISAM': myisam-storage-engine.; *Note `NDB': mysql-cluster. should do the same.) (Bug #55121) * *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. `--nodaemon' logged to the console in addition to the configured log destination. (Bug #54779) * The warning `MaxNoOfExecutionThreads (#) > LockExecuteThreadToCPU count (#), this could cause contention' could be logged when running *Note `ndbd': mysql-cluster-programs-ndbd, even though the condition described can occur only when using *Note `ndbmtd': mysql-cluster-programs-ndbmtd. (Bug #54342) * Startup messages previously written by *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. to `stdout' are now written to the cluster log instead when `LogDestination' is set. (Bug #47595) * The graceful shutdown of a data node could sometimes cause transactions to be aborted unnecessarily. (Bug #18538) See also Bug #55641. *Changes in MySQL Cluster NDB 7.1.6 (5.1.47-ndb-7.1.6) * *Functionality added or changed:* * Added the `DictTrace' data node configuration parameter, for use in debugging *Note `NDB': mysql-cluster. code. For more information, see *Note mysql-cluster-ndbd-definition::. (Bug #55963) * Added the `--server-id-bits' option for mysqld and mysqlbinlog. For *Note `mysqld': mysqld, the `--server-id-bits' option indicates the number of least significant bits within the 32-bit server ID which actually identify the server. Indicating that the server ID uses less than 32 bits permits the remaining bits to be used for other purposes by NDB API applications using the Event API and `OperationOptions::AnyValue'. For *Note `mysqlbinlog': mysqlbinlog, the `--server-id-bits' option tells *Note `mysqlbinlog': mysqlbinlog. how to interpret the server IDs in the binary log when the binary log was written by a *Note `mysqld': mysqld. having its `server_id_bits' set to less than the maximum (32). (Bug #52305) *Bugs fixed:* * *Cluster API*: *Important Change*: The poll and select calls made by the MGM API were not interrupt-safe; that is, a signal caught by the process while waiting for an event on one or more sockets returned error -1 with `errno' set to EINTR. This caused problems with MGM API functions such as `ndb_logevent_get_next()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-logevent-get-next.html) and `ndb_mgm_get_status2()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-get-status2.html). To fix this problem, the internal `ndb_socket_poller::poll()' function has been made EINTR-safe. The old version of this function has been retained as `poll_unsafe()', for use by those parts of NDB that do not need the EINTR-safe version of the function. (Bug #55906) * The TCP configuration parameters `HostName1' and `HostName2' were not displayed in the output of *Note `ndb_config': mysql-cluster-programs-ndb-config. `--configinfo'. (Bug #55839) * When another data node failed, a given data node `DBTC' kernel block could time out while waiting for `DBDIH' to signal commits of pending transactions, leading to a crash. Now in such cases the timeout generates a prinout, and the data node continues to operate. (Bug #55715) * Starting *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. with `--config-cache=0' caused it to leak memory. (Bug #55205) * The `configure.js' option `WITHOUT_DYNAMIC_PLUGINS=TRUE' was ignored when building MySQL Cluster for Windows using `CMake'. Among the effects of this issue was that `CMake' attempted to build the `InnoDB' storage engine as a plugin (`.DLL' file) even though the `InnoDB Plugin' is not currently supported by MySQL Cluster. (Bug #54913) * It was possible for a *Note `DROP DATABASE': drop-database. statement to remove *Note `NDB': mysql-cluster. hidden blob tables without removing the parent tables, with the result that the tables, although hidden to MySQL clients, were still visible in the output of *Note `ndb_show_tables': mysql-cluster-programs-ndb-show-tables. but could not be dropped using *Note `ndb_drop_table': mysql-cluster-programs-ndb-drop-table. (Bug #54788) * An excessive number of timeout warnings (normally used only for debugging) were written to the data node logs. (Bug #53987) * *Disk Data*: As an optimization when inserting a row to an empty page, the page is not read, but rather simply initialized. However, this optimzation was performed in all cases when an empty row was inserted, even though it should have been done only if it was the first time that the page had been used by a table or fragment. This is because, if the page had been in use, and then all records had been released from it, the page still needed to be read to learn its log sequence number (LSN). This caused problems only if the page had been flushed using an incorrect LSN and the data node failed before any local checkpoint was completed--which would removed any need to apply the undo log, hence the incorrect LSN was ignored. The user-visible result of the incorrect LSN was that it caused the data node to fail during a restart. It was perhaps also possible (although not conclusively proven) that this issue could lead to incorrect data. (Bug #54986) * *Cluster API*: Calling `NdbTransaction::refresh()' did not update the timer for `TransactionInactiveTimeout'. (Bug #54724) *Changes in MySQL Cluster NDB 7.1.5 (5.1.47-ndb-7.1.5) * *Functionality added or changed:* * Restrictions on some types of mismatches in column definitions when restoring data using *Note `ndb_restore': mysql-cluster-programs-ndb-restore. have been relaxed. These include the following types of mismatches: * Different `COLUMN_FORMAT' settings (`FIXED', `DYNAMIC', `DEFAULT') * Different `STORAGE' settings (`MEMORY', `DISK') * Different default values * Different distribution key settings Now, when one of these types of mismatches in column definitions is encountered, *Note `ndb_restore': mysql-cluster-programs-ndb-restore. no longer stops with an error; instead, it accepts the data and inserts it into the target table, while issuing a warning to the user. For more information, see *Note mysql-cluster-programs-ndb-restore::. (Bug #54423) See also Bug #53810, Bug #54178, Bug #54242, Bug #54279. * It is now possible to install management node and data node processes as Windows services. (See *Note mysql-cluster-install-windows-service::, for more information.) In addition, data node processes on Windows are now maintained by angel processes, just as they are on other platforms supported by MySQL Cluster. *Bugs fixed:* * The disconnection of all API nodes (including SQL nodes) during an *Note `ALTER TABLE': alter-table. caused a memory leak. (Bug #54685) * If a node shutdown (either in isolation or as part of a system shutdown) occurred directly following a local checkpoint, it was possible that this local checkpoint would not be used when restoring the cluster. (Bug #54611) * The setting for `BuildIndexThreads' was ignored by *Note `ndbmtd': mysql-cluster-programs-ndbmtd, which made it impossible to use more than 4 cores for rebuilding indexes. (Bug #54521) * When adding multiple new node groups to a MySQL Cluster, it was necessary for each new node group to add only the nodes to be assigned to the new node group, create that node group using `CREATE NODEGROUP', then repeat this process for each new node group to be added to the cluster. The fix for this issue makes it possible to add all of the new nodes at one time, and then issue several `CREATE NODEGROUP' commands in succession. (Bug #54497) * When performing an online alter table where 2 or more SQL nodes connected to the cluster were generating binary logs, an incorrect message could be sent from the data nodes, causing *Note `mysqld': mysqld. processes to crash. This problem was often difficult to detect, because restarting SQL node or data node processes could clear the error, and because the crash in *Note `mysqld': mysqld. did not occur until several minutes after the erroneous message was sent and received. (Bug #54168) * A table having the maximum number of attributes permitted could not be backed up using the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client. *Note*: The maximum number of attributes supported per table is not the same for all MySQL Cluster releases. See *Note mysql-cluster-limitations-database-objects::, to determine the maximum that applies in the release which you are using. (Bug #54155) * The presence of duplicate `[tcp]' sections in the `config.ini' file caused the management server to crash. Now in such cases, *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. fails gracefully with an appropriate error message. (Bug #49400) * The two MySQL Server options, `--ndb-wait-connected' and `--ndb-wait-setup', did not set the corresponding system variables. (Bug #48402) * *Cluster API*: When using the NDB API, it was possible to rename a table with the same name as that of an existing table. *Note*: This issue did not affect table renames executed using SQL on MySQL servers acting as MySQL Cluster API nodes. (Bug #54651) * *Cluster API*: An excessive number of client connections, such that more than 1024 file descriptors, sockets, or both were open, caused NDB API applications to crash. (Bug #34303) *Changes in MySQL Cluster NDB 7.1.4 (5.1.44-ndb-7.1.4) * *Functionality added or changed:* * *Important Change*: The maximum number of attributes (columns plus indexes) per table has increased to 512. * A `--wait-nodes' option has been added for *Note `ndb_waiter': mysql-cluster-programs-ndb-waiter. When this option is used, the program waits only for the nodes having the listed IDs to reach the desired state. For more information, see *Note mysql-cluster-programs-ndb-waiter::. (Bug #52323) * As part of this change, new methods relating to default values have been added to the `Column' and `Table' classes in the NDB API. For more information, see `Column::getDefaultValue()' (http://dev.mysql.com/doc/ndbapi/en/ndb-column-methods.html#ndb-column-getdefaultvalue), `Column::setDefaultValue()' (http://dev.mysql.com/doc/ndbapi/en/ndb-column-methods.html#ndb-column-setdefaultvalue), and `Table::hasDefaultValues()' (http://dev.mysql.com/doc/ndbapi/en/ndb-table-methods.html#ndb-table-hasdefaultvalues). (Bug #30529) * Added the MySQL Cluster management server option `--config-cache', which makes it possible to enable and disable configuration caching. This option is turned on by default; to disable configuration caching, start *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. with `--config-cache=0', or with `--skip-config-cache'. See *Note mysql-cluster-programs-ndb-mgmd::, for more information. * Added the `--skip-unknown-objects' option for *Note `ndb_restore': mysql-cluster-programs-ndb-restore. This option causes *Note `ndb_restore': mysql-cluster-programs-ndb-restore. to ignore any schema objects which it does not recognize. Currently, this is useful chiefly for restoring native backups made from a cluster running MySQL Cluster NDB 7.0 to a cluster running MySQL Cluster NDB 6.3. *Bugs fixed:* * *Cluster API*: *Incompatible Change*: The default behavior of the NDB API Event API has changed as follows: Previously, when creating an `Event', DDL operations (alter and drop operations on tables) were automatically reported on any event operation that used this event, but as a result of this change, this is no longer the case. Instead, you must now invoke the event's `setReport()' method, with the new `EventReport' value `ER_DDL', to get this behavior. For existing NDB API applications where you wish to retain the old behavior, you must update the code as indicated previously, then recompile, following an upgrade. Otherwise, DDL operations are no longer reported after upgrading `libndbnclient'. For more information, see The `Event::EventReport' Type (http://dev.mysql.com/doc/ndbapi/en/ndb-event-types.html#ndb-event-eventreport), and `Event::setReport()' (http://dev.mysql.com/doc/ndbapi/en/ndb-event-methods.html#ndb-event-setreport). (Bug #53308) * *Cluster API*: *Incompatible Change*: The default behavior of the NDB API Event API has changed as follows: Previously, when creating an `Event', DDL operations (alter and drop operations on tables) were automatically reported on any event operation that used this event, but as a result of this change, this is no longer the case. Instead, you must now invoke the event's `setReport()' method, with the new `EventReport' value `ER_DDL', to get this behavior. For existing NDB API applications where you wish to retain the old behavior, you must update the code as indicated previously, then recompile, following an upgrade. Otherwise, DDL operations are no longer reported after upgrading `libndbnclient'. For more information, see The `Event::EventReport' Type (http://dev.mysql.com/doc/ndbapi/en/ndb-event-types.html#ndb-event-eventreport), and `Event::setReport()' (http://dev.mysql.com/doc/ndbapi/en/ndb-event-methods.html#ndb-event-setreport). (Bug #53308) * After creating *Note `NDB': mysql-cluster. tables until creation of a table failed due to *Note `NDB': mysql-cluster. error 905 `Out of attribute records (increase MaxNoOfAttributes)', then increasing `MaxNoOfAttributes' and restarting all management node and data node processes, attempting to drop and re-create one of the tables failed with the error `Out of table records...', even when sufficient table records were available. (Bug #53944) See also Bug #52055. * Creating a Disk Data table, dropping it, then creating an in-memory table and performing a restart, could cause data node processes to fail with errors in the `DBTUP' kernel block if the new table's internal ID was the same as that of the old Disk Data table. This could occur because undo log handling during the restart did not check that the table having this ID was now in-memory only. (Bug #53935) * A table created while `ndb_table_no_logging' was enabled was not always stored to disk, which could lead to a data node crash with `Error opening DIH schema files for table'. (Bug #53934) * An internal buffer allocator used by *Note `NDB': mysql-cluster. has the form `alloc(WANTED, MINIMUM)' and attempts to allocate WANTED pages, but is permitted to allocate a smaller number of pages, between WANTED and MINIMUM. However, this allocator could sometimes allocate fewer than MINIMUM pages, causing problems with multi-threaded building of ordered indexes. (Bug #53580) * When compiled with support for `epoll' but this functionality is not available at runtime, MySQL Cluster tries to fall back to use the `select()' function in its place. However, an extra `ndbout_c()' call in the transporter registry code caused *Note `ndbd': mysql-cluster-programs-ndbd. to fail instead. (Bug #53482) * The value set for the *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. option `--ndb-nodeid' was not verified prior to use as being within the permitted range (1 to 255, inclusive), leading to a crash of the management server. (Bug #53412) * `NDB' truncated a column declared as *Note `DECIMAL(65,0)': numeric-types. to a length of 64. Now such a column is accepted and handled correctly. In cases where the maximum length (65) is exceeded, `NDB' now raises an error instead of truncating. (Bug #53352) * When an `NDB' log handler failed, the memory allocated to it was freed twice. (Bug #53200) * Setting `DataMemory' higher than 4G on 32-bit platforms caused *Note `ndbd': mysql-cluster-programs-ndbd. to crash, instead of failing gracefully with an error. (Bug #52536, Bug #50928) * When the `LogDestination' parameter was set using with a relative path, the management server failed to store its value unless started with `--initial' or `--reload'. (Bug #52268) * When creating an index, *Note `NDB': mysql-cluster. failed to check whether the internal ID allocated to the index was within the permissible range, leading to an assertion. This issue could manifest itself as a data node failure with `NDB' error 707 (`No more table metadata records (increase MaxNoOfTables)'), when creating tables in rapid succession (for example, by a script, or when importing from *Note `mysqldump': mysqldump.), even with a relatively high value for `MaxNoOfTables' and a relatively low number of tables. (Bug #52055) * *Note `ndb_restore': mysql-cluster-programs-ndb-restore. did not raise any errors if hashmap creation failed during execution. (Bug #51434) * Specifying the node ID as part of the `--ndb-connectstring' option to *Note `mysqld': mysqld. was not handled correctly. The fix for this issue includes the following changes: * Multiple occurrences of any of the *Note `mysqld': mysqld. options `--ndb-connectstring', `--ndb-mgmd-host', and `--ndb-nodeid' are now handled in the same way as with other MySQL server options, in that the value set in the last occurrence of the option is the value that is used by *Note `mysqld': mysqld. Now, if `--ndb-nodeid' is used, its value overrides that of any `nodeid' setting used in `--ndb-connectstring'. For example, starting *Note `mysqld': mysqld. with `--ndb-connectstring=nodeid=1,10.100.1.100 --ndb-nodeid=3' now produces the same result as starting it with `--ndb-connectstring=nodeid=3,10.100.1.100'. * The 1024-character limit on the length of the connectstring is removed, and `--ndb-connectstring' is now handled in this regard in the same way as other *Note `mysqld': mysqld. options. * In the NDB API, a new constructor for `Ndb_cluster_connection' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndb-cluster-connection.html#ndb-ndb-cluster-connection) is added which takes as its arguments a connectstring and the node ID to force the API node to use. (Bug #44299) * NDB did not distinguish correctly between table names differing only by lettercase when `lower_case_table_names' was set to 0. (Bug #33158) * `ndb_mgm -e "ALL STATUS"' erroneously reported that data nodes remained in start phase 0 until they had actually started. *Changes in MySQL Cluster NDB 7.1.3 (5.1.44-ndb-7.1.3) * *Functionality added or changed:* * *Incompatible Change*: The schema for the *Note `memoryusage': mysql-cluster-ndbinfo-memoryusage. table of the *Note `ndbinfo': mysql-cluster-ndbinfo. information database has changed, as detailed in the following list: * The `max' column has been renamed to `total'. * The `used' and `total' (formerly `max') columns now display values in bytes rather than memory pages. * Added the columns `used_pages' and `total_pages' to show the amount of a resource used and total amount available in pages. * The size of the memory pages used for calculating data memory (`used_pages' and `total_pages' columns) is now 32K rather than 16K. For more information, aee *Note mysql-cluster-ndbinfo-memoryusage::. * *Incompatible Change*: The schema for the *Note `memoryusage': mysql-cluster-ndbinfo-memoryusage. table of the *Note `ndbinfo': mysql-cluster-ndbinfo. information database has changed, as detailed in the following list: * The `max' column has been renamed to `total'. * The `used' and `total' (formerly `max') columns now display values in bytes rather than memory pages. * Added the columns `used_pages' and `total_pages' to show the amount of a resource used and total amount available in pages. * The size of the memory pages used for calculating data memory (`used_pages' and `total_pages' columns) is now 32K rather than 16K. For more information, aee *Note mysql-cluster-ndbinfo-memoryusage::. * *Important Change*: The experimental *Note `pools': mysql-cluster-ndbinfo-pools. table has been removed from the *Note `ndbinfo': mysql-cluster-ndbinfo. database. Information useful to MySQL Cluster administration that was contained in this table should be available from other *Note `ndbinfo': mysql-cluster-ndbinfo. tables. * *Important Note*: MySQL Cluster 7.1 is now supported for production use on Windows platforms. *Important*: Some limitations specific to Windows remain; the most important of these are given in the following list: * There is not yet any Windows installer for MySQL Cluster; you must extract, place, configure, and start the necessary MySQL Cluster executables manually. * MySQL Cluster processes cannot yet be installed as Windows services. This means that each process executable must be run from a command prompt, and cannot be backgrounded. If you close the command prompt window in which you started the process, the process terminates. * There is as yet no `angel' process for data nodes; if a data node process quits, it must be restarted manually. * *Note `ndb_error_reporter': mysql-cluster-programs-ndb-error-reporter. is not yet available on Windows. * The multi-threaded data node process (*Note `ndbmtd': mysql-cluster-programs-ndbmtd.) is not yet included in the binary distribution. However, it should be built automatically if you build MySQL Cluster from source. As with MySQL Cluster on other supported platforms, you cannot build MySQL Cluster for Windows from the MySQL Server 5.1 sources; you must use the source code from the MySQL Cluster NDB 7.1 tree. *Bugs fixed:* * If a node or cluster failure occurred while *Note `mysqld': mysqld. was scanning the `ndb.ndb_schema' table (which it does when attempting to connect to the cluster), insufficient error handling could lead to a crash by *Note `mysqld': mysqld. in certain cases. This could happen in a MySQL Cluster with a great many tables, when trying to restart data nodes while one or more *Note `mysqld': mysqld. processes were restarting. (Bug #52325) * In MySQL Cluster NDB 7.0 and later, DDL operations are performed within schema transactions; the NDB kernel code for starting a schema transaction checks that all data nodes are at the same version before permitting a schema transaction to start. However, when a version mismatch was detected, the client was not actually informed of this problem, which caused the client to hang. (Bug #52228) * After running a mixed series of node and system restarts, a system restart could hang or fail altogether. This was caused by setting the value of the newest completed global checkpoint too low for a data node performing a node restart, which led to the node reporting incorrect GCI intervals for its first local checkpoint. (Bug #52217) * When performing a complex mix of node restarts and system restarts, the node that was elected as master sometimes required optimized node recovery due to missing `REDO' information. When this happened, the node crashed with `Failure to recreate object ... during restart, error 721' (because the `DBDICT' restart code was run twice). Now when this occurs, node takeover is executed immediately, rather than being made to wait until the remaining data nodes have started. (Bug #52135) See also Bug #48436. * The internal variable `ndb_new_handler', which is no longer used, has been removed. (Bug #51858) * `ha_ndbcluster.cc' was not compiled with the same `SAFEMALLOC' and `SAFE_MUTEX' flags as the MySQL Server. (Bug #51857) * When debug compiling MySQL Cluster on Windows, the mysys library was not compiled with -DSAFEMALLOC and -DSAFE_MUTEX, due to the fact that my_socket.c was misnamed as my_socket.cc. (Bug #51856) * Some values shown in the *Note `memoryusage': mysql-cluster-ndbinfo-memoryusage. table did not match corresponding values shown by the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client `ALL REPORT MEMORYUSAGE' command. (Bug #51735) * The redo log protects itself from being filled up by periodically checking how much space remains free. If insufficient redo log space is available, it sets the state `TAIL_PROBLEM' which results in transactions being aborted with error code 410 (`out of redo log'). However, this state was not set following a node restart, which meant that if a data node had insufficient redo log space following a node restart, it could crash a short time later with `Fatal error due to end of REDO log'. Now, this space is checked during node restarts. (Bug #51723) * Restoring a MySQL Cluster backup between platforms having different endianness failed when also restoring metadata and the backup contained a hashmap not already present in the database being restored to. This issue was discovered when trying to restore a backup made on Solaris/SPARC to a MySQL Cluster running on Solaris/x86, but could conceivably occur in other cases where the endianness of the platform on which the backup was taken differed from that of the platform being restored to. (Bug #51432) * A *Note `mysqld': mysqld, when attempting to access the *Note `ndbinfo': mysql-cluster-ndbinfo. database, crashed if could not contact the management server. (Bug #51067) * The *Note `mysql': mysql. client `system' command did not work properly. This issue was only known to affect the version of the *Note `mysql': mysql. client that was included with MySQL Cluster NDB 7.0 and MySQL Cluster NDB 7.1 releases. (Bug #48574) * *Cluster API*: *Packaging*: The file `META-INF/services/org.apache.openjpa.lib.conf.ProductDerivation' was missing from the `clusterjpa' JAR file. This could cause setting `openjpa.BrokerFactory' to ``ndb'' to be rejected. (Bug #52106) * *Disk Data*: Inserts of blob column values into a MySQL Cluster Disk Data table that exhausted the tablespace resulted in misleading `no such tuple' error messages rather than the expected error `tablespace full'. This issue appeared similar to Bug#48113, but had a different underlying cause. (Bug #52201) * *Disk Data*: DDL operations on Disk Data tables having a relatively small `UNDO_BUFFER_SIZE' could fail unexpectedly. * *Cluster API*: A number of issues were corrected in the NDB API coding examples found in the `storage/ndb/ndbapi-examples' directory in the MySQL Cluster source tree. These included possible endless recursion in `ndbapi_scan.cpp' as well as problems running some of the examples on systems using Windows or Mac OS X due to the lettercase used for some table names. (Bug #30552, Bug #30737) *Changes in MySQL Cluster NDB 7.1.2 (5.1.41-ndb-7.1.2) * *Functionality added or changed:* * *Cluster API*: It is now possible to determine, using the *Note `ndb_desc': mysql-cluster-programs-ndb-desc. utility or the NDB API, which data nodes contain replicas of which partitions. For *Note `ndb_desc': mysql-cluster-programs-ndb-desc, a new `--extra-node-info' option is added to cause this information to be included in its output. A new method `Table::getFragmentNodes()' is added to the NDB API for obtaining this information programmatically. (Bug #51184) * *Cluster API*: It is now possible to determine, using the *Note `ndb_desc': mysql-cluster-programs-ndb-desc. utility or the NDB API, which data nodes contain replicas of which partitions. For *Note `ndb_desc': mysql-cluster-programs-ndb-desc, a new `--extra-node-info' option is added to cause this information to be included in its output. A new method `Table::getFragmentNodes()' is added to the NDB API for obtaining this information programmatically. (Bug #51184) * Numeric codes used in management server status update messages in the cluster logs have been replaced with text descriptions. (Bug #49627) See also Bug #44248. * A new configuration parameter `HeartbeatThreadPriority' makes it possible to select between a first-in, first-out or round-round scheduling policy for management node and API node heartbeat threads, as well as to set the priority of these threads. See *Note mysql-cluster-mgm-definition::, or *Note mysql-cluster-api-definition::, for more information. (Bug #49617) * Start phases are now written to the data node logs. (Bug #49158) * Formerly, the `REPORT' and `DUMP' commands returned output to all *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. clients connected to the same MySQL Cluster. Now, these commands return their output only to the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client that actually issued the command. (Bug #40865) * *Disk Data*: The *Note `ndb_desc': mysql-cluster-programs-ndb-desc. utility can now show the extent space and free extent space for subordinate *Note `BLOB': blob. and *Note `TEXT': blob. columns (stored in hidden `BLOB' tables by NDB). A `--blob-info' option has been added for this program that causes *Note `ndb_desc': mysql-cluster-programs-ndb-desc. to generate a report for each subordinate `BLOB' table. For more information, see *Note mysql-cluster-programs-ndb-desc::. (Bug #50599) *Bugs fixed:* * *Important Change*: The `DATA_MEMORY' column of the *Note `memoryusage': mysql-cluster-ndbinfo-memoryusage. table was renamed to `memory_type'. (Bug #50926) * When deciding how to divide the REDO log, the `DBDIH' kernel block saved more than was needed to restore the previous local checkpoint, which could cause REDO log space to be exhausted prematurely (`NDB' error 410). (Bug #51547) * DML operations can fail with `NDB' error 1220 (`REDO log files overloaded...') if the opening and closing of REDO log files takes too much time. If this occurred as a GCI marker was being written in the REDO log while REDO log file 0 was being opened or closed, the error could persist until a GCP stop was encountered. This issue could be triggered when there was insufficient REDO log space (for example, with configuration parameter settings `NoOfFragmentLogFiles = 6' and `FragmentLogFileSize = 6M') with a load including a very high number of updates. (Bug #51512) See also Bug #20904. * An attempted online upgrade from a MySQL Cluster NDB 6.3 or 7.0 release to a MySQL Cluster NDB 7.1 release failed, as the first upgraded data node rejected the remaining data nodes as using incompatible versions. (Bug #51429) * A side effect of the *Note `ndb_restore': mysql-cluster-programs-ndb-restore. `--disable-indexes' and `--rebuild-indexes' options is to change the schema versions of indexes. When a *Note `mysqld': mysqld. later tried to drop a table that had been restored from backup using one or both of these options, the server failed to detect these changed indexes. This caused the table to be dropped, but the indexes to be left behind, leading to problems with subsequent backup and restore operations. (Bug #51374) * The output of the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client `REPORT BACKUPSTATUS' command could sometimes contain errors due to uninitialized data. (Bug #51316) * Setting `IndexMemory' greater than 2GB could cause data nodes to crash while starting. (Bug #51256) * *Note `ndb_restore': mysql-cluster-programs-ndb-restore. crashed while trying to restore a corrupted backup, due to missing error handling. (Bug #51223) * The *Note `ndb_restore': mysql-cluster-programs-ndb-restore. message `Successfully created index `PRIMARY`...' was directed to `stderr' instead of `stdout'. (Bug #51037) * An initial restart of a data node configured with a large amount of memory could fail with a `Pointer too large' error. (Bug #51027) This regression was introduced by Bug #47818. * When using `NoOfReplicas' equal to 1 or 2, if data nodes from one node group were restarted 256 times and applications were running traffic such that it would encounter *Note `NDB': mysql-cluster. error 1204 (`Temporary failure, distribution changed'), the live node in the node group would crash, causing the cluster to crash as well. The crash occurred only when the error was encountered on the 256th restart; having the error on any previous or subsequent restart did not cause any problems. (Bug #50930) * A `GROUP BY' query against *Note `NDB': mysql-cluster. tables sometimes did not use any indexes unless the query included a `FORCE INDEX' option. With this fix, indexes are used by such queries (where otherwise possible) even when `FORCE INDEX' is not specified. (Bug #50736) * *Note `ndbmtd': mysql-cluster-programs-ndbmtd. started on a single-core machine could sometimes fail with a `Job Buffer Full' error when `MaxNoOfExecutionThreads' was set greater than `LockExecuteThreadToCPU'. Now a warning is logged when this occurs. (Bug #50582) * The following issues were fixed in the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client `REPORT MEMORYUSAGE' command: * The client sometimes inserted extra `ndb_mgm>' prompts within the output. * For data nodes running *Note `ndbmtd': mysql-cluster-programs-ndbmtd, `IndexMemory' was reported before `DataMemory'. * In addition, for data nodes running *Note `ndbmtd': mysql-cluster-programs-ndbmtd, there were multiple `IndexMemory' entries listed in the output. (Bug #50196) * Issuing a command in the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client after it had lost its connection to the management server could cause the client to crash. (Bug #49219) * Replication of a MySQL Cluster using multi-threaded data nodes could fail with forced shutdown of some data nodes due to the fact that *Note `ndbmtd': mysql-cluster-programs-ndbmtd. exhausted `LongMessageBuffer' much more quickly than *Note `ndbd': mysql-cluster-programs-ndbd. After this fix, passing of replication data between the `DBTUP' and `SUMA' NDB kernel blocks is done using `DataMemory' rather than `LongMessageBuffer'. Until you can upgrade, you may be able to work around this issue by increasing the `LongMessageBuffer' setting; doubling the default should be sufficient in most cases. (Bug #46914) * Information about several management client commands was missing from (that is, truncated in) the output of the `HELP' command. (Bug #46114) * A *Note `SELECT': select. requiring a sort could fail with the error `Can't find record in 'TABLE'' when run concurrently with a *Note `DELETE': delete. from the same table. (Bug #45687) * When the `MemReportFrequency' configuration parameter was set in `config.ini', the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client `REPORT MEMORYUSAGE' command printed its output multiple times. (Bug #37632) * *Note `ndb_mgm -e "... REPORT ..."': mysql-cluster-programs-ndb-mgm. did not write any output to `stdout'. The fix for this issue also prevents the cluster log from being flooded with `INFO' messages when `DataMemory' usage reaches 100%, and insures that when the usage is decreased, an appropriate message is written to the cluster log. (Bug #31542, Bug #44183, Bug #49782) * *Disk Data*: The error message returned after atttempting to execute *Note `ALTER LOGFILE GROUP': alter-logfile-group. on an nonexistent logfile group did not indicate the reason for the failure. (Bug #51111) * *Cluster API*: An issue internal to *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. could cause problems when trying to start a large number of data nodes at the same time. (Bug #51273) See also Bug #51310. * *Cluster API*: When reading blob data with lock mode `LM_SimpleRead', the lock was not upgraded as expected. (Bug #51034) *Changes in MySQL Cluster NDB 7.1.1 (5.1.41-ndb-7.1.1) * *Functionality added or changed:* * The *Note `ndbinfo': mysql-cluster-ndbinfo. database is added to provide MySQL Cluster metadata in real time. The tables making up this database contain information about memory, buffer, and other resource usage, as well as configuration parameters and settings, event counts, and other useful data. Access to *Note `ndbinfo': mysql-cluster-ndbinfo. is done by executing standard SQL queries on its tables using the *Note `mysql': mysql. command-line client or other MySQL client application. No special setup procedures are required; *Note `ndbinfo': mysql-cluster-ndbinfo. is created automatically and visible in the output of *Note `SHOW DATABASES': show-databases. when the MySQL Server is connected to a MySQL Cluster. For more information, see *Note mysql-cluster-ndbinfo::. * *Cluster API*: ClusterJ 1.0 and ClusterJPA 1.0 are now available for programming Java applications with MySQL Cluster. ClusterJ is a Java connector providing an object-relational API for performing high-speed operations such as primary key lookups on a MySQL Cluster database, but does not require the use of the MySQL Server or JDBC (Connector/J). ClusterJ uses a new library NdbJTie which enables direct access from Java to the NDB API and thus to the *Note `NDBCLUSTER': mysql-cluster. storage engine. ClusterJPA is a new implementation of OpenJPA (http://openjpa.apache.org/), and can use either a JDBC connection to a MySQL Cluster SQL node (MySQL Server) or a direct connection to MySQL Cluster using NdbJTie, depending on availability and operational performance. ClusterJ, ClusterJPA, and NdbJTie require Java 1.5 or 1.6, and MySQL Cluster NDB 7.0 or later. All necessary libraries and other files for ClusterJ, ClusterJPA, and NdbJTie can be found in the MySQL Cluster NDB 7.1.1 or later distribution. *Bugs fixed:* * When a primary key lookup on an *Note `NDB': mysql-cluster. table containing one or more *Note `BLOB': blob. columns was executed in a transaction, a shared lock on any blob tables used by the *Note `NDB': mysql-cluster. table was held for the duration of the transaction. (This did not occur for indexed or non-indexed `WHERE' conditions.) Now in such cases, the lock is released after all *Note `BLOB': blob. data has been read. (Bug #49190) *Changes in MySQL Cluster NDB 7.1.0 (5.1.39-ndb-7.1.0) * *Functionality added or changed:* * *Important Change*: The default value of the `DiskIOThreadPool' data node configuration parameter has changed from 8 to 2. *Bugs fixed:* * *Important Change*: The `--with-ndb-port-base' option for `configure' has been removed. It is now handled as an unknown and invalid option if you attempt to use it when configuring a build of MySQL Cluster. (Bug #47941) See also Bug #38502. * The value set by the `--ndb-cluster-connection-pool' option was not shown in the output of *Note `SHOW STATUS LIKE 'NDB%'': show-status. (Bug #44118)  File: manual.info, Node: mysql-cluster-news-7-0-series, Next: mysql-cluster-news-6-3-series, Prev: mysql-cluster-news-7-1-series, Up: mysql-cluster-news-series 17.7.7.2 Changes in the MySQL Cluster NDB 7.0 Series .................................................... This section contains unified change history highlights for all MySQL Cluster releases based on version 7.0 of the *Note `NDBCLUSTER': mysql-cluster. storage engine through MySQL Cluster NDB 7.0.27. Included are all changelog entries in the categories _MySQL Cluster_, _Disk Data_, and _Cluster API_. Early MySQL Cluster NDB 7.0 releases tagged `NDB 6.4.x' are also included in this listing. For an overview of features that were added in MySQL Cluster NDB 7.0, see *Note mysql-cluster-development-5-1-ndb-7-0::. * Changes in MySQL Cluster NDB 7.0.26 (5.1.56-ndb-7.0.26) * Changes in MySQL Cluster NDB 7.0.25 (5.1.56-ndb-7.0.25) * Changes in MySQL Cluster NDB 7.0.24 (5.1.56-ndb-7.0.24) * Changes in MySQL Cluster NDB 7.0.23 (5.1.51-ndb-7.0.23) * Changes in MySQL Cluster NDB 7.0.22 (5.1.51-ndb-7.0.22) * Changes in MySQL Cluster NDB 7.0.21 (5.1.51-ndb-7.0.21) * Changes in MySQL Cluster NDB 7.0.20a (5.1.51-ndb-7.0.20a) * Changes in MySQL Cluster NDB 7.0.19 (5.1.47-ndb-7.0.19) * Changes in MySQL Cluster NDB 7.0.18 (5.1.47-ndb-7.0.18) * Changes in MySQL Cluster NDB 7.0.17 (5.1.47-ndb-7.0.17) * Changes in MySQL Cluster NDB 7.0.16 (5.1.47-ndb-7.0.16) * Changes in MySQL Cluster NDB 7.0.15b (5.1.44-ndb-7.0.15b) * Changes in MySQL Cluster NDB 7.0.14 (5.1.44-ndb-7.0.14) * Changes in MySQL Cluster NDB 7.0.13 (5.1.41-ndb-7.0.13) * Changes in MySQL Cluster NDB 7.0.12 (5.1.41-ndb-7.0.12) * Changes in MySQL Cluster NDB 7.0.11 (5.1.41-ndb-7.0.11) * Changes in MySQL Cluster NDB 7.0.10 (5.1.39-ndb-7.0.10) * Changes in MySQL Cluster NDB 7.0.9a (5.1.39-ndb-7.0.9a) * Changes in MySQL Cluster NDB 7.0.8a (5.1.37-ndb-7.0.8a) * Changes in MySQL Cluster NDB 7.0.7 (5.1.35-ndb-7.0.7) * Changes in MySQL Cluster NDB 7.0.6 (5.1.34-ndb-7.0.6) * Changes in MySQL Cluster NDB 7.0.5 (5.1.32-ndb-7.0.5) * Changes in MySQL Cluster NDB 7.0.4 (5.1.32-ndb-7.0.4) * Changes in MySQL Cluster NDB 6.4.3 (5.1.32-ndb-6.4.3) * Changes in MySQL Cluster NDB 6.4.2 (5.1.31-ndb-6.4.2) * Changes in MySQL Cluster NDB 6.4.1 (5.1.31-ndb-6.4.1) * Changes in MySQL Cluster NDB 6.4.0 (5.1.30-ndb-6.4.0) *Changes in MySQL Cluster NDB 7.0.26 (5.1.56-ndb-7.0.26) * *Functionality added or changed:* * Added the `MaxDMLOperationsPerTransaction' data node configuration parameter, which can be used to limit the number of DML operations used by a transaction; if the transaction requires more than this many DML operations, the transaction is aborted. (Bug #12589613) *Bugs fixed:* * When global checkpoint indexes were written with no intervening end-of-file or megabyte border markers, this could sometimes lead to a situation in which the end of the redo log was mistakenly regarded as being between these GCIs, so that if the restart of a data node took place before the start of the next redo log was overwritten, the node encountered an `Error while reading the REDO log'. (Bug #12653993, Bug #61500) See also Bug #56961. * Restarting a *Note `mysqld': mysqld. during a rolling upgrade with data nodes running a mix of old and new versions of the MySQL Cluster software caused the *Note `mysqld': mysqld. to run in read-only mode. (Bug #12651364, Bug #61498) * Error reporting has been improved for cases in which API nodes are unable to connect due to apparent unavailability of node IDs. (Bug #12598398) * Error messages for `Failed to convert connection' transporter registration problems were inspecific. (Bug #12589691) * Under certain rare circumstances, a data node process could fail with Signal 11 during a restart. This was due to uninitialized variables in the `QMGR' kernel block. (Bug #12586190) * Multiple management servers were unable to detect one another until all nodes had fully started. As part of the fix for this issue, two new status values `RESUME' and `CONNECTED' can be reported for management nodes in the output of the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client `SHOW' command (see *Note mysql-cluster-mgm-client-commands::). Two corresponding status values `NDB_MGM_NODE_STATUS_RESUME' and `NDB_MGM_NODE_STATUS_CONNECTED' are also added to the list of possible values for an `ndb_mgm_node_status' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-node-status.html) data structure in the MGM API. (Bug #12352191, Bug #48301) * Handling of the `MaxNoOfTables' and `MaxNoOfAttributes' configuration parameters was not consistent in all parts of the *Note `NDB': mysql-cluster. kernel, and were only strictly enforced by the `DBDICT' and `SUMA' kernel blocks. This could lead to problems when tables could be created but not replicated. Now these parameters are treated by `SUMA' and `DBDICT' as suggested maximums rather than hard limits, as they are elsewhere in the *Note `NDB': mysql-cluster. kernel. (Bug #61684) * It was not possible to shut down a management node while one or more data nodes were stopped (for whatever reason). This issue was a regression introduced in MySQL Cluster NDB 7.0.24 and MySQL Cluster NDB 7.1.13. (Bug #61607) See also Bug #61147. * *Cluster API*: Applications that included the header file `ndb_logevent.h' could not be built using the Microsoft Visual Studio C compiler or the Oracle (Sun) Studio C compiler due to empty struct definitions. (Bug #12678971) * *Cluster API*: Within a transaction, after creating, executing, and closing a scan, calling `NdbTransaction::refresh()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndbtransaction-methods.html#ndb-ndbtransaction-refresh) after creating and executing but not closing a second scan caused the application to crash. (Bug #12646659) *Changes in MySQL Cluster NDB 7.0.25 (5.1.56-ndb-7.0.25) * *Bugs fixed:* * The internal `Ndb_getinaddr()' function has been rewritten to use `getaddrinfo()' instead of `my_gethostbyname_r()' (which is removed in a later version of the MySQL Server). (Bug #12542120) * Two unused test files in `storage/ndb/test/sql' contained incorrect versions of the GNU Lesser General Public License. The files and the directory containing them have been removed. (Bug #11810156) See also Bug #11810224. * Error 1302 gave the wrong error message (`Out of backup record'). This has been corrected to `A backup is already running'. (Bug #11793592) * When using two management servers, issuing in an *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client connected to one management server a `STOP' command for stopping the other management server caused Error 2002 (`Stop failed ... Send to process or receive failed.: Permanent error: Application error'), even though the `STOP' command actually succeeded, and the second *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. was shut down. (Bug #61147) * In *Note `ndbmtd': mysql-cluster-programs-ndbmtd, a node connection event is detected by a `CMVMI' thread which sends a `CONNECT_REP' signal to the `QMGR' kernel block. In a few isolated circumstances, a signal might be transfered to `QMGR' directly by the *Note `NDB': mysql-cluster. transporter before the `CONNECT_REP' signal actually arrived. This resulted in reports in the error log with status `Temporary error, restart node', and the message `Internal program error'. (Bug #61025) * Renaming a table having *Note `BLOB': blob. or *Note `TEXT': blob. columns (or both) to another database caused the SQL node to crash, and the table to become inaccessible afterwards. (Bug #60484) * Under heavy loads with many concurrent inserts, temporary failures in transactions could occur (and were misreported as being due to *Note `NDB': mysql-cluster. Error 899 `Rowid already allocated'). As part of the fix for this issue, *Note `NDB': mysql-cluster. Error 899 has been reclassified as an internal error, rather than as a temporary transaction error. (Bug #56051, Bug #11763354) * *Disk Data*: Accounting for `MaxNoOfOpenFiles' was incorrect with regard to to data files in MySQL Cluster Disk Data tablespaces. This could lead to a crash when `MaxNoOfOpenFiles' was exceeded. (Bug #12581213) *Changes in MySQL Cluster NDB 7.0.24 (5.1.56-ndb-7.0.24) * *Functionality added or changed:* * It is now possible to add data nodes online to a running MySQL Cluster without performing a rolling restart of the cluster or starting data node processes with the `--nowait-nodes' option. This can be done by setting `Nodegroup = 65536' in the `config.ini' file for any data nodes that should be started at a later time, when first starting the cluster. (It was possible to set `NodeGroup' to this value previously, but the management server failed to start.) As part of this fix, a new data node configuration parameter `StartNoNodeGroupTimeout' has been added. When the management server sees that there are data nodes with no node group (that is, nodes for which `Nodegroup = 65536'), it waits `StartNoNodeGroupTimeout' milliseconds before treating these nodes as though they were listed with the `--nowait-nodes' option, and proceeds to start. For more information, see *Note mysql-cluster-online-add-node::. (Bug #11766167, Bug #59213) * A `config_generation' column has been added to the *Note `nodes': mysql-cluster-ndbinfo-nodes. table of the *Note `ndbinfo': mysql-cluster-ndbinfo. database. By checking this column, it is now possible to determine which version or versions of the MySQL Cluster configuration file are in effect on the data nodes. This information can be especially useful when performing a rolling restart of the cluster in order to update its configuration. *Bugs fixed:* * *Cluster API*: A unique index operation is executed in two steps: a lookup on an index table, and an operation on the base table. When the operation on the base table failed, while being executed in a batch with other operations that succeeded, this could lead to a hanging execute, eventually timing out with Error 4012 (`Request ndbd time-out, maybe due to high load or communication problems'). (Bug #12315582) * *Cluster API*: A unique index operation is executed in two steps: a lookup on an index table, and an operation on the base table. When the operation on the base table failed, while being executed in a batch with other operations that succeeded, this could lead to a hanging execute, eventually timing out with Error 4012 (`Request ndbd time-out, maybe due to high load or communication problems'). (Bug #12315582) * A memory leak in `LGMAN', that leaked 8 bytes of log buffer memory per 32k written, was introduced in MySQL Cluster NDB 7.0.9, effecting all MySQL Cluster NDB 7.1 releases as well as MySQL Cluster NDB 7.0.9 and later MySQL Cluster NDB 7.0 releases. (For example, when 128 MB log buffer memory was used, it was exhausted after writing 512 GB to the undo log.) This led to a GCP stop and data node failure. (Bug #60946) This regression was introduced by Bug #47966. * When using *Note `ndbmtd': mysql-cluster-programs-ndbmtd, a MySQL Cluster configured with 32 data nodes failed to start correctly. (Bug #60943) * When performing a TUP scan with locks in parallel, and with a highly concurrent load of inserts and deletions, the scan could sometimes fail to notice that a record had moved while waiting to acquire a lock on it, and so read the wrong record. During node recovery, this could lead to a crash of a node that was copying data to the node being started, and a possible forced shutdown of the cluster. * *Cluster API*: Performing interpreted operations using a unique index did not work correctly, because the interpret bit was kept when sending the lookup to the index table. *Changes in MySQL Cluster NDB 7.0.23 (5.1.51-ndb-7.0.23) * *Functionality added or changed:* * Improved scaling of ordered index scans performance by removing a hard-coded limit (`MAX_PARALLEL_INDEX_SCANS_PER_FRAG') and making the number of `TUP' or `TUX' scans per fragment configurable by adding the `MaxParallelScansPerFragment' data node configuration parameter. (Bug #11769048) *Bugs fixed:* * *Important Change*: Formerly, the `--ndb-cluster-connection-pool' server option set a status variable as well as a system variable. The status variable has been removed as redundant. (Bug #60119) * A scan with a pushed condition (filter) using the `CommittedRead' lock mode could hang for a short interval when it was aborted when just as it had decided to send a batch. (Bug #11932525) * When aborting a multi-read range scan exactly as it was changing ranges in the local query handler, LQH could fail to detect it, leaving the scan hanging. (Bug #11929643) * Schema distribution did not take place for tables converted from another storage engine to *Note `NDB': mysql-cluster. using *Note `ALTER TABLE': alter-table.; this meant that such tables were not always visible to all SQL nodes attached to the cluster. (Bug #11894966) * A GCI value inserted by *Note `ndb_restore': mysql-cluster-programs-ndb-restore. `--restore_epoch' into the `ndb_apply_status' table was actually 1 less than the correct value. (Bug #11885852) * *Disk Data*: Limits imposed by the size of `SharedGlobalMemory' were not always enforced consistently with regard to Disk Data undo buffers and log files. This could sometimes cause a *Note `CREATE LOGFILE GROUP': create-logfile-group. or *Note `ALTER LOGFILE GROUP': alter-logfile-group. statement to fail for no apparent reason, or cause the log file group specified by `InitialLogFileGroup' not to be created when starting the cluster. (Bug #57317) *Changes in MySQL Cluster NDB 7.0.22 (5.1.51-ndb-7.0.22) * *Functionality added or changed:* * *Disk Data*: The *Note `INFORMATION_SCHEMA.TABLES': tables-table. table now provides disk usage as well as memory usage information for Disk Data tables. Also, *Note `INFORMATION_SCHEMA.PARTITIONS': partitions-table, formerly did not show any statistics for *Note `NDB': mysql-cluster. tables. Now the `TABLE_ROWS', `AVG_ROW_LENGTH', `DATA_LENGTH', `MAX_DATA_LENGTH', and `DATA_FREE' columns contain correct information for the table's partitions. * *Disk Data*: The *Note `INFORMATION_SCHEMA.TABLES': tables-table. table now provides disk usage as well as memory usage information for Disk Data tables. Also, *Note `INFORMATION_SCHEMA.PARTITIONS': partitions-table, formerly did not show any statistics for *Note `NDB': mysql-cluster. tables. Now the `TABLE_ROWS', `AVG_ROW_LENGTH', `DATA_LENGTH', `MAX_DATA_LENGTH', and `DATA_FREE' columns contain correct information for the table's partitions. * A new `--rewrite-database' option is added for *Note `ndb_restore': mysql-cluster-programs-ndb-restore, which makes it possible to restore to a database having a different name from that of the database in the backup. For more information, see *Note mysql-cluster-programs-ndb-restore::. (Bug #54327) *Bugs fixed:* * *Important Note*: Due to an error in merging the original fix, it did not appear MySQL Cluster NDB 7.0.21; this oversight has been corrected in the current release. (Bug #58256) * This issue affects all previous MySQL Cluster NDB 7.0 releases. (Bug #60045) * *Note `ndb_restore `--rebuild-indexes'': mysql-cluster-programs-ndb-restore. caused multi-threaded index building to occur on the master node only. (Bug #59920) * Successive queries on the *Note `counters': mysql-cluster-ndbinfo-counters. table from the same SQL node returned unchanging results. To fix this issue, and to prevent similar issues from occurring in the future, *Note `ndbinfo': mysql-cluster-ndbinfo. tables are now excluded from the query cache. (Bug #59831) * When a *Note `CREATE TABLE': create-table. statement failed due to *Note `NDB': mysql-cluster. error 1224 (`Too many fragments'), it was not possible to create the table afterward unless either it had no ordered indexes, or a *Note `DROP TABLE': drop-table. statement was issued first, even if the subsequent *Note `CREATE TABLE': create-table. was valid and should otherwise have succeeded. (Bug #59756) See also Bug #59751. * When attempting to create a table on a MySQL Cluster with many standby data nodes (setting `Nodegroup=65536' in `config.ini' for the nodes that should wait, starting the nodes that should start immediately with the `--nowait-nodes' option, and using the *Note `CREATE TABLE': create-table. statement's `MAX_ROWS' option), *Note `mysqld': mysqld. miscalculated the number of fragments to use. This caused the *Note `CREATE TABLE': create-table. to fail. *Note*: The *Note `CREATE TABLE': create-table. failure caused by this issue in turn prevented any further attempts to create the table, even if the table structure was simplified or changed in such a way that the attempt should have succeeded. This `ghosting' issue is handled in BUG#59756. (Bug #59751) * *Note `NDB': mysql-cluster. sometimes treated a simple (not unique) ordered index as unique. (Bug #59519) * The logic used in determining whether to collapse a range to a simple equality was faulty. In certain cases, this could cause *Note `NDB': mysql-cluster. to treat a range as if it were a primary key lookup when determining the query plan to be used. Although this did not affect the actual result returned by the query, it could in such cases result in inefficient execution of queries due to the use of an inappropriate query plan. (Bug #59517) * When a query used multiple references to or instances of the same physical tables, *Note `NDB': mysql-cluster. failed to recognize these multiple instances as different tables; in such a case, *Note `NDB': mysql-cluster. could incorrectly use condition pushdown on a condition referring to these other instances to be pushed to the data nodes, even though the condition should have been rejected as unpushable, leading to invalid results. (Bug #58791) * *Cluster API*: When calling `NdbEventOperation::execute()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndbeventoperation-methods.html#ndb-ndbeventoperation-execute) during a node restart, it was possible to get a spurious error 711 (`System busy with node restart, schema operations not allowed when a node is starting'). (Bug #59723) * *Cluster API*: When an NDBAPI client application was waiting for more scan results after calling `NdbScanOperation::nextResult()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndbscanoperation-methods.html#ndb-ndbscanoperation-nextresult), the calling thread sometimes woke up even if no new batches for any fragment had arrived, which was unnecessary, and which could have a negative impact on the application's performance. (Bug #52298) *Changes in MySQL Cluster NDB 7.0.21 (5.1.51-ndb-7.0.21) * *Functionality added or changed:* * *Important Change*: The following changes have been made with regard to the `TimeBetweenEpochsTimeout' data node configuration parameter: * The maximum possible value for this parameter has been increased from 32000 milliseconds to 256000 milliseconds. * Setting this parameter to zero now has the effect of disabling GCP stops caused by save timeouts, commit timeouts, or both. * The current value of this parameter and a warning are written to the cluster log whenever a GCP save takes longer than 1 minute or a GCP commit takes longer than 10 seconds. For more information, see *Note mysql-cluster-ndbd-definition-gcp-stop-errors::. (Bug #58383) * Added the `--skip-broken-objects' option for *Note `ndb_restore': mysql-cluster-programs-ndb-restore. This option causes *Note `ndb_restore': mysql-cluster-programs-ndb-restore. to ignore tables corrupted due to missing blob parts tables, and to continue reading from the backup file and restoring the remaining tables. (Bug #54613) See also Bug #51652. * *Cluster API*: It is now possible to stop or restart a node even while other nodes are starting, using the MGM API `ndb_mgm_stop4()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-stop4.html) or `ndb_mgm_restart4()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-restart4.html) function, respectively, with the FORCE parameter set to 1. (Bug #58451) See also Bug #58319. *Bugs fixed:* * *Cluster API*: In some circumstances, very large *Note `BLOB': blob. read and write operations in MySQL Cluster applications can cause excessive resource usage and even exhaustion of memory. To fix this issue and to provide increased stability when performing such operations, it is now possible to set limits on the volume of *Note `BLOB': blob. data to be read or written within a given transaction in such a way that when these limits are exceeded, the current transaction implicitly executes any accumulated operations. This avoids an excessive buildup of pending data which can result in resource exhaustion in the NDB kernel. The limits on the amount of data to be read and on the amount of data to be written before this execution takes place can be configured separately. (In other words, it is now possible in MySQL Cluster to specify read batching and write batching that is specific to *Note `BLOB': blob. data.) These limits can be configured either on the NDB API level, or in the MySQL Server. On the NDB API level, four new methods are added to the `NdbTransaction' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndbtransaction.html#ndb-ndbtransaction) object. `getMaxPendingBlobReadBytes()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndbtransaction-methods.html#ndb-ndbtransaction-getmaxpendingblobreadbytes) and `setMaxPendingBlobReadBytes()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndbtransaction-methods.html#ndb-ndbtransaction-setmaxpendingblobreadbytes) can be used to get and to set, respectively, the maximum amount of *Note `BLOB': blob. data to be read that accumulates before this implicit execution is triggered. `getMaxPendingBlobWriteBytes()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndbtransaction-methods.html#ndb-ndbtransaction-getmaxpendingblobwritebytes) and `setMaxPendingBlobWriteBytes()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndbtransaction-methods.html#ndb-ndbtransaction-setmaxpendingblobwritebytes) can be used to get and to set, respectively, the maximum volume of *Note `BLOB': blob. data to be written that accumulates before implicit execution occurs. For the MySQL server, two new options are added. The `--ndb-blob-read-batch-bytes' option sets a limit on the amount of pending *Note `BLOB': blob. data to be read before triggering implicit execution, and the `--ndb-blob-write-batch-bytes' option controls the amount of pending *Note `BLOB': blob. data to be written. These limits can also be set using the *Note `mysqld': mysqld. configuration file, or read and set within the *Note `mysql': mysql. client and other MySQL client applications using the corresponding server system variables. (Bug #59113) * *Cluster API*: In some circumstances, very large *Note `BLOB': blob. read and write operations in MySQL Cluster applications can cause excessive resource usage and even exhaustion of memory. To fix this issue and to provide increased stability when performing such operations, it is now possible to set limits on the volume of *Note `BLOB': blob. data to be read or written within a given transaction in such a way that when these limits are exceeded, the current transaction implicitly executes any accumulated operations. This avoids an excessive buildup of pending data which can result in resource exhaustion in the NDB kernel. The limits on the amount of data to be read and on the amount of data to be written before this execution takes place can be configured separately. (In other words, it is now possible in MySQL Cluster to specify read batching and write batching that is specific to *Note `BLOB': blob. data.) These limits can be configured either on the NDB API level, or in the MySQL Server. On the NDB API level, four new methods are added to the `NdbTransaction' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndbtransaction.html#ndb-ndbtransaction) object. `getMaxPendingBlobReadBytes()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndbtransaction-methods.html#ndb-ndbtransaction-getmaxpendingblobreadbytes) and `setMaxPendingBlobReadBytes()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndbtransaction-methods.html#ndb-ndbtransaction-setmaxpendingblobreadbytes) can be used to get and to set, respectively, the maximum amount of *Note `BLOB': blob. data to be read that accumulates before this implicit execution is triggered. `getMaxPendingBlobWriteBytes()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndbtransaction-methods.html#ndb-ndbtransaction-getmaxpendingblobwritebytes) and `setMaxPendingBlobWriteBytes()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndbtransaction-methods.html#ndb-ndbtransaction-setmaxpendingblobwritebytes) can be used to get and to set, respectively, the maximum volume of *Note `BLOB': blob. data to be written that accumulates before implicit execution occurs. For the MySQL server, two new options are added. The `--ndb-blob-read-batch-bytes' option sets a limit on the amount of pending *Note `BLOB': blob. data to be read before triggering implicit execution, and the `--ndb-blob-write-batch-bytes' option controls the amount of pending *Note `BLOB': blob. data to be written. These limits can also be set using the *Note `mysqld': mysqld. configuration file, or read and set within the *Note `mysql': mysql. client and other MySQL client applications using the corresponding server system variables. (Bug #59113) * Two related problems could occur with read-committed scans made in parallel with transactions combining multiple (concurrent) operations: 1. When committing a multiple-operation transaction that contained concurrent insert and update operations on the same record, the commit arrived first for the insert and then for the update. If a read-committed scan arrived between these operations, it could thus read incorrect data; in addition, if the scan read variable-size data, it could cause the data node to fail. 2. When rolling back a multiple-operation transaction having concurrent delete and insert operations on the same record, the abort arrived first for the delete operation, and then for the insert. If a read-committed scan arrived between the delete and the insert, it could incorrectly assume that the record should not be returned (in other words, the scan treated the insert as though it had not yet been committed). (Bug #59496) * On Windows platforms, issuing a `SHUTDOWN' command in the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client caused management processes that had been started with the `--nodaemon' option to exit abnormally. (Bug #59437) * A row insert or update followed by a delete operation on the same row within the same transaction could in some cases lead to a buffer overflow. (Bug #59242) See also Bug #56524. This regression was introduced by Bug #35208. * Data nodes configured with very large amounts (multiple gigabytes) of `DiskPageBufferMemory' failed during startup with NDB error 2334 (`Job buffer congestion'). (Bug #58945) See also Bug #47984. * The `FAIL_REP' signal, used inside the NDB kernel to declare that a node has failed, now includes the node ID of the node that detected the failure. This information can be useful in debugging. (Bug #58904) * When executing a full table scan caused by a `WHERE' condition using `UNIQUE_KEY IS NULL' in combination with a join, *Note `NDB': mysql-cluster. failed to close the scan. (Bug #58750) See also Bug #57481. * In some circumstances, an SQL trigger on an *Note `NDB': mysql-cluster. table could read stale data. (Bug #58538) * During a node takeover, it was possible in some circumstances for one of the remaining nodes to send an extra transaction confirmation (`LQH_TRANSCONF') signal to the `DBTC' kernel block, conceivably leading to a crash of the data node trying to take over as the new transaction coordinator. (Bug #58453) * A query having multiple predicates joined by `OR' in the `WHERE' clause and which used the `sort_union' access method (as shown using *Note `EXPLAIN': explain.) could return duplicate rows. (Bug #58280) * Trying to drop an index while it was being used to perform scan updates caused data nodes to crash. (Bug #58277, Bug #57057) * When handling failures of multiple data nodes, an error in the construction of internal signals could cause the cluster's remaining nodes to crash. This issue was most likely to affect clusters with large numbers of data nodes. (Bug #58240) * The functions `strncasecmp' and `strcasecmp' were declared in `ndb_global.h' but never defined or used. The declarations have been removed. (Bug #58204) * Some queries of the form *Note `SELECT ... WHERE COLUMN IN (SUBQUERY)': select. against an *Note `NDB': mysql-cluster. table could cause *Note `mysqld': mysqld. to hang in an endless loop. (Bug #58163) * The number of rows affected by a statement that used a `WHERE' clause having an `IN' condition with a value list containing a great many elements, and that deleted or updated enough rows such that *Note `NDB': mysql-cluster. processed them in batches, was not computed or reported correctly. (Bug #58040) * MySQL Cluster failed to compile correctly on FreeBSD 8.1 due to misplaced `#include' statements. (Bug #58034) * A query using `BETWEEN' as part of a pushed-down `WHERE' condition could cause mysqld to hang or crash. (Bug #57735) * Data nodes no longer allocated all memory prior to being ready to exchange heartbeat and other messages with management nodes, as in NDB 6.3 and earlier versions of MySQL Cluster. This caused problems when data nodes configured with large amounts of memory failed to show as connected or showed as being in the wrong start phase in the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client even after making their initial connections to and fetching their configuration data from the management server. With this fix, data nodes now allocate all memory as they did in earlier MySQL Cluster versions. (Bug #57568) * In some circumstances, it was possible for *Note `mysqld': mysqld. to begin a new multi-range read scan without having closed a previous one. This could lead to exhaustion of all scan operation objects, transaction objects, or lock objects (or some combination of these) in *Note `NDB': mysql-cluster, causing queries to fail with such errors as `Lock wait timeout exceeded' or `Connect failure - out of connection objects'. (Bug #57481) See also Bug #58750. * Queries using `COLUMN IS' [`NOT'] `NULL' on a table with a unique index created with `USING HASH' on COLUMN always returned an empty result. (Bug #57032) * With `engine_condition_pushdown' enabled, a query using `LIKE' on an *Note `ENUM': enum. column of an *Note `NDB': mysql-cluster. table failed to return any results. This issue is resolved by disabling `engine_condition_pushdown' when performing such queries. (Bug #53360) * When a slash character (`/') was used as part of the name of an index on an *Note `NDB': mysql-cluster. table, attempting to execute a *Note `TRUNCATE TABLE': truncate-table. statement on the table failed with the error `Index not found', and the table was rendered unusable. (Bug #38914) * *Disk Data*: *Partitioning*: When using multi-threaded data nodes, an *Note `NDB': mysql-cluster. table created with a very large value for the `MAX_ROWS' option could--if this table was dropped and a new table with fewer partitions, but having the same table ID, was created--cause *Note `ndbmtd': mysql-cluster-programs-ndbmtd. to crash when performing a system restart. This was because the server attempted to examine each partition whether or not it actually existed. This issue is the same as that reported in Bug#45154, except that the current issue is specific to *Note `ndbmtd': mysql-cluster-programs-ndbmtd. instead of *Note `ndbd': mysql-cluster-programs-ndbd. (Bug #58638) * *Disk Data*: In certain cases, a race condition could occur when *Note `DROP LOGFILE GROUP': drop-logfile-group. removed the logfile group while a read or write of one of the effected files was in progress, which in turn could lead to a crash of the data node. (Bug #59502) * *Disk Data*: A race condition could sometimes be created when *Note `DROP TABLESPACE': drop-tablespace. was run concurrently with a local checkpoint; this could in turn lead to a crash of the data node. (Bug #59501) * *Disk Data*: Performing what should have been an online drop of a multi-column index was actually performed offline. (Bug #55618) * *Disk Data*: When at least one data node was not running, queries against the *Note `INFORMATION_SCHEMA.FILES': files-table. table took an excessive length of time to complete because the MySQL server waited for responses from any stopped nodes to time out. Now, in such cases, MySQL does not attempt to contact nodes which are not known to be running. (Bug #54199) * *Cluster API*: It was not possible to obtain the status of nodes accurately after an attempt to stop a data node using `ndb_mgm_stop()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-stop.html) failed without returning an error. (Bug #58319) * *Cluster API*: Attempting to read the same value (using `getValue()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndboperation-methods.html#ndb-ndboperation-getvalue)) more than 9000 times within the same transaction caused the transaction to hang when executed. Now when more reads are performed in this way than can be accommodated in a single transaction, the call to `execute()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndbtransaction-methods.html#ndb-ndbtransaction-execute) fails with a suitable error. (Bug #58110) *Changes in MySQL Cluster NDB 7.0.20a (5.1.51-ndb-7.0.20a) * *Bugs fixed:* * *Important Note*: Issuing an `ALL DUMP' command during a rolling upgrade to MySQL Cluster NDB 7.0.20 caused the cluster to crash. (Bug #58256) *Changes in MySQL Cluster NDB 7.0.19 (5.1.47-ndb-7.0.19) * *Functionality added or changed:* * *Note `mysqldump': mysqldump. as supplied with MySQL Cluster now has an `--add-drop-trigger' option which adds a *Note `DROP TRIGGER IF EXISTS': drop-trigger. statement before each dumped trigger definition. (Bug #55691) See also Bug #34325, Bug #11747863. * It is now possible using the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. management client or the MGM API to force a data node shutdown or restart even if this would force the shutdown or restart of the entire cluster. In the management client, this is implemented through the addition of the `-f' (force) option to the `STOP' and `RESTART' commands. For more information, see *Note mysql-cluster-mgm-client-commands::. The MGM API also adds two new methods for forcing such a node shutdown or restart; see `ndb_mgm_stop4()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-stop4.html), and `ndb_mgm_restart4()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-restart4.html), for more information about these methods. (Bug #54226) * *Cluster API*: The MGM API function `ndb_mgm_get_version()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-get-version.html), which was previously internal, has now been moved to the public API. This function can be used to get `NDB' storage engine and other version information from the management server. (Bug #51310) See also Bug #51273. *Bugs fixed:* * At startup, an *Note `ndbd': mysql-cluster-programs-ndbd. or *Note `ndbmtd': mysql-cluster-programs-ndbmtd. process creates directories for its file system without checking to see whether they already exist. Portability code added in MySQL Cluster NDB 7.0.18 and MySQL Cluster NDB 7.1.7 did not account for this fact, printing a spurious error message when a directory to be created already existed. This unneeded printout has been removed. (Bug #57087) * A data node can be shut down having completed and synchronized a given GCI X, while having written a great many log records belonging to the next GCI X + 1, as part of normal operations. However, when starting, completing, and synchronizing GCI X + 1, then the log records from original start must not be read. To make sure that this does not happen, the REDO log reader finds the last GCI to restore, scans forward from that point, and erases any log records that were not (and should never be) used. The current issue occurred because this scan stopped immediately as soon as it encountered an empty page. This was problematic because the REDO log is divided into several files; thus, it could be that there were log records in the beginning of the next file, even if the end of the previous file was empty. These log records were never invalidated; following a start or restart, they could be reused, leading to a corrupt REDO log. (Bug #56961) * An error in program flow in `ndbd.cpp' could result in data node shutdown routines being called multiple times. (Bug #56890) * Under certain rare conditions, attempting to start more than one *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. process simultaneously using the `--reload' option caused a race condition such that none of the *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. processes could start. (Bug #56844) * When distributing *Note `CREATE TABLE': create-table. and *Note `DROP TABLE': drop-table. operations among several SQL nodes attached to a MySQL Cluster. the `LOCK_OPEN' lock normally protecting *Note `mysqld': mysqld.'s internal table list is released so that other queries or DML statements are not blocked. However, to make sure that other DDL is not executed simultaneously, a global schema lock (implemented as a row-level lock by `NDB') is used, such that all operations that can modify the state of the *Note `mysqld': mysqld. internal table list also need to acquire this global schema lock. The *Note `SHOW TABLE STATUS': show-table-status. statement did not acquire this lock. (Bug #56841) * In certain cases, *Note `DROP DATABASE': drop-database. could sometimes leave behind a cached table object, which caused problems with subsequent DDL operations. (Bug #56840) * Memory pages used for `DataMemory', once assigned to ordered indexes, were not ever freed, even after any rows that belonged to the corresponding indexes had been deleted. (Bug #56829) * MySQL Cluster stores, for each row in each `NDB' table, a Global Checkpoint Index (GCI) which identifies the last committed transaction that modified the row. As such, a GCI can be thought of as a coarse-grained row version. Due to changes in the format used by `NDB' to store local checkpoints (LCPs) in MySQL Cluster NDB 6.3.11, it could happen that, following cluster shutdown and subsequent recovery, the GCI values for some rows could be changed unnecessarily; this could possibly, over the course of many node or system restarts (or both), lead to an inconsistent database. (Bug #56770) * When multiple SQL nodes were connected to the cluster and one of them stopped in the middle of a DDL operation, the *Note `mysqld': mysqld. process issuing the DDL timed out with the error `distributing TBL_NAME timed out. Ignoring'. (Bug #56763) * An online *Note `ALTER TABLE ... ADD COLUMN': alter-table. operation that changed the table schema such that the number of 32-bit words used for the bitmask allocated to each DML operation increased during a transaction in DML which was performed prior to DDL which was followed by either another DML operation or--if using replication--a commit, led to data node failure. This was because the data node did not take into account that the bitmask for the before-image was smaller than the current bitmask, which caused the node to crash. (Bug #56524) * On Windows, a data node refused to start in some cases unless the *Note `ndbd.exe': mysql-cluster-programs-ndbd. executable was invoked using an absolute rather than a relative path. (Bug #56257) * The text file `cluster_change_hist.txt' containing old MySQL Cluster changelog information was no longer being maintained, and so has been removed from the tree. (Bug #56116) * The failure of a data node during some scans could cause other data nodes to fail. (Bug #54945) * Exhausting the number of available commit-ack markers (controlled by the `MaxNoOfConcurrentTransactions' parameter) led to a data node crash. (Bug #54944) * When running a *Note `SELECT': select. on an *Note `NDB': mysql-cluster. table with *Note `BLOB': blob. or *Note `TEXT': blob. columns, memory was allocated for the columns but was not freed until the end of the *Note `SELECT': select. This could cause problems with excessive memory usage when dumping (using for example *Note `mysqldump': mysqldump.) tables with such columns and having many rows, large column values, or both. (Bug #52313) See also Bug #56488, Bug #50310. * *Cluster API*: The MGM API functions `ndb_mgm_stop()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-stop.html) and `ndb_mgm_restart()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-restart.html) set the error code and message without first checking whether the management server handle was `NULL', which could lead to fatal errors in MGM API applications that depended on these functions. (Bug #57089) * *Cluster API*: The MGM API function `ndb_mgm_get_version()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-get-version.html) did not set the error message before returning with an error. With this fix, it is now possible to call `ndb_mgm_get_latest_error()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-get-latest-error.html) after a failed call to this function such that `ndb_mgm_get_latest_error()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-get-latest-error.html) returns an error number and error message, as expected of MGM API calls. (Bug #57088) *Changes in MySQL Cluster NDB 7.0.18 (5.1.47-ndb-7.0.18) * *Functionality added or changed:* * *Important Change*: More finely-grained control over restart-on-failure behavior is provided with two new data node configuration parameters `MaxStartFailRetries' and `StartFailRetryDelay'. `MaxStartFailRetries' limits the total number of retries made before giving up on starting the data node; `StartFailRetryDelay' sets the number of seconds between retry attempts. These parameters are used only if `StopOnError' is set to 0. For more information, see *Note mysql-cluster-ndbd-definition::. (Bug #54341) *Bugs fixed:* * *Note `ndb_restore': mysql-cluster-programs-ndb-restore. always reported 0 for the `GCPStop' (end point of the backup). Now it provides useful binary log position and epoch information. (Bug #56298) * The `LockExecuteThreadToCPU' configuration parameter was not handled correctly for CPU ID values greater than 255. (Bug #56185) * Following a failure of the master data node, the new master sometimes experienced a race condition which caused the node to terminate with a GcpStop error. (Bug #56044) * Trying to create a table having a *Note `BLOB': blob. or *Note `TEXT': blob. column with `DEFAULT ''' failed with the error `Illegal null attribute'. (An empty default is allowed and ignored by *Note `MyISAM': myisam-storage-engine.; *Note `NDB': mysql-cluster. should do the same.) (Bug #55121) * *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. `--nodaemon' logged to the console in addition to the configured log destination. (Bug #54779) * The warning `MaxNoOfExecutionThreads (#) > LockExecuteThreadToCPU count (#), this could cause contention' could be logged when running *Note `ndbd': mysql-cluster-programs-ndbd, even though the condition described can occur only when using *Note `ndbmtd': mysql-cluster-programs-ndbmtd. (Bug #54342) * Startup messages previously written by *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. to `stdout' are now written to the cluster log instead when `LogDestination' is set. (Bug #47595) * The graceful shutdown of a data node could sometimes cause transactions to be aborted unnecessarily. (Bug #18538) See also Bug #55641. *Changes in MySQL Cluster NDB 7.0.17 (5.1.47-ndb-7.0.17) * *Functionality added or changed:* * Added the `DictTrace' data node configuration parameter, for use in debugging *Note `NDB': mysql-cluster. code. For more information, see *Note mysql-cluster-ndbd-definition::. (Bug #55963) * Added the `--server-id-bits' option for mysqld and mysqlbinlog. For *Note `mysqld': mysqld, the `--server-id-bits' option indicates the number of least significant bits within the 32-bit server ID which actually identify the server. Indicating that the server ID uses less than 32 bits permits the remaining bits to be used for other purposes by NDB API applications using the Event API and `OperationOptions::AnyValue'. For *Note `mysqlbinlog': mysqlbinlog, the `--server-id-bits' option tells *Note `mysqlbinlog': mysqlbinlog. how to interpret the server IDs in the binary log when the binary log was written by a *Note `mysqld': mysqld. having its `server_id_bits' set to less than the maximum (32). (Bug #52305) *Bugs fixed:* * *Cluster API*: *Important Change*: The poll and select calls made by the MGM API were not interrupt-safe; that is, a signal caught by the process while waiting for an event on one or more sockets returned error -1 with `errno' set to EINTR. This caused problems with MGM API functions such as `ndb_logevent_get_next()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-logevent-get-next.html) and `ndb_mgm_get_status2()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-get-status2.html). To fix this problem, the internal `ndb_socket_poller::poll()' function has been made EINTR-safe. The old version of this function has been retained as `poll_unsafe()', for use by those parts of NDB that do not need the EINTR-safe version of the function. (Bug #55906) * The TCP configuration parameters `HostName1' and `HostName2' were not displayed in the output of *Note `ndb_config': mysql-cluster-programs-ndb-config. `--configinfo'. (Bug #55839) * When another data node failed, a given data node `DBTC' kernel block could time out while waiting for `DBDIH' to signal commits of pending transactions, leading to a crash. Now in such cases the timeout generates a prinout, and the data node continues to operate. (Bug #55715) * Starting *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. with `--config-cache=0' caused it to leak memory. (Bug #55205) * The `configure.js' option `WITHOUT_DYNAMIC_PLUGINS=TRUE' was ignored when building MySQL Cluster for Windows using `CMake'. Among the effects of this issue was that `CMake' attempted to build the `InnoDB' storage engine as a plugin (`.DLL' file) even though the `InnoDB Plugin' is not currently supported by MySQL Cluster. (Bug #54913) * It was possible for a *Note `DROP DATABASE': drop-database. statement to remove *Note `NDB': mysql-cluster. hidden blob tables without removing the parent tables, with the result that the tables, although hidden to MySQL clients, were still visible in the output of *Note `ndb_show_tables': mysql-cluster-programs-ndb-show-tables. but could not be dropped using *Note `ndb_drop_table': mysql-cluster-programs-ndb-drop-table. (Bug #54788) * An excessive number of timeout warnings (normally used only for debugging) were written to the data node logs. (Bug #53987) * *Disk Data*: As an optimization when inserting a row to an empty page, the page is not read, but rather simply initialized. However, this optimzation was performed in all cases when an empty row was inserted, even though it should have been done only if it was the first time that the page had been used by a table or fragment. This is because, if the page had been in use, and then all records had been released from it, the page still needed to be read to learn its log sequence number (LSN). This caused problems only if the page had been flushed using an incorrect LSN and the data node failed before any local checkpoint was completed--which would removed any need to apply the undo log, hence the incorrect LSN was ignored. The user-visible result of the incorrect LSN was that it caused the data node to fail during a restart. It was perhaps also possible (although not conclusively proven) that this issue could lead to incorrect data. (Bug #54986) * *Cluster API*: Calling `NdbTransaction::refresh()' did not update the timer for `TransactionInactiveTimeout'. (Bug #54724) *Changes in MySQL Cluster NDB 7.0.16 (5.1.47-ndb-7.0.16) * *Functionality added or changed:* * Restrictions on some types of mismatches in column definitions when restoring data using *Note `ndb_restore': mysql-cluster-programs-ndb-restore. have been relaxed. These include the following types of mismatches: * Different `COLUMN_FORMAT' settings (`FIXED', `DYNAMIC', `DEFAULT') * Different `STORAGE' settings (`MEMORY', `DISK') * Different default values * Different distribution key settings Now, when one of these types of mismatches in column definitions is encountered, *Note `ndb_restore': mysql-cluster-programs-ndb-restore. no longer stops with an error; instead, it accepts the data and inserts it into the target table, while issuing a warning to the user. For more information, see *Note mysql-cluster-programs-ndb-restore::. (Bug #54423) See also Bug #53810, Bug #54178, Bug #54242, Bug #54279. * Introduced the `HeartbeatOrder' data node configuration parameter, which can be used to set the order in which heartbeats are transmitted between data nodes. This parameter can be useful in situations where multiple data nodes are running on the same host and a temporary disruption in connectivity between hosts would otherwise cause the loss of a node group, leading to failure of the cluster. (Bug #52182) * It is now possible to install management node and data node processes as Windows services. (See *Note mysql-cluster-install-windows-service::, for more information.) In addition, data node processes on Windows are now maintained by angel processes, just as they are on other platforms supported by MySQL Cluster. *Bugs fixed:* * The disconnection of all API nodes (including SQL nodes) during an *Note `ALTER TABLE': alter-table. caused a memory leak. (Bug #54685) * If a node shutdown (either in isolation or as part of a system shutdown) occurred directly following a local checkpoint, it was possible that this local checkpoint would not be used when restoring the cluster. (Bug #54611) * The setting for `BuildIndexThreads' was ignored by *Note `ndbmtd': mysql-cluster-programs-ndbmtd, which made it impossible to use more than 4 cores for rebuilding indexes. (Bug #54521) * When adding multiple new node groups to a MySQL Cluster, it was necessary for each new node group to add only the nodes to be assigned to the new node group, create that node group using `CREATE NODEGROUP', then repeat this process for each new node group to be added to the cluster. The fix for this issue makes it possible to add all of the new nodes at one time, and then issue several `CREATE NODEGROUP' commands in succession. (Bug #54497) * When performing an online alter table where 2 or more SQL nodes connected to the cluster were generating binary logs, an incorrect message could be sent from the data nodes, causing *Note `mysqld': mysqld. processes to crash. This problem was often difficult to detect, because restarting SQL node or data node processes could clear the error, and because the crash in *Note `mysqld': mysqld. did not occur until several minutes after the erroneous message was sent and received. (Bug #54168) * A table having the maximum number of attributes permitted could not be backed up using the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client. *Note*: The maximum number of attributes supported per table is not the same for all MySQL Cluster releases. See *Note mysql-cluster-limitations-database-objects::, to determine the maximum that applies in the release which you are using. (Bug #54155) * During initial node restarts, initialization of the REDO log was always performed 1 node at a time, during start phase 4. Now this is done during start phase 2, so that the initialization can be performed in parallel, thus decreasing the time required for initial restarts involving multiple nodes. (Bug #50062) * The presence of duplicate `[tcp]' sections in the `config.ini' file caused the management server to crash. Now in such cases, *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. fails gracefully with an appropriate error message. (Bug #49400) * The two MySQL Server options, `--ndb-wait-connected' and `--ndb-wait-setup', did not set the corresponding system variables. (Bug #48402) * *Cluster API*: When using the NDB API, it was possible to rename a table with the same name as that of an existing table. *Note*: This issue did not affect table renames executed using SQL on MySQL servers acting as MySQL Cluster API nodes. (Bug #54651) * *Cluster API*: An excessive number of client connections, such that more than 1024 file descriptors, sockets, or both were open, caused NDB API applications to crash. (Bug #34303) *Changes in MySQL Cluster NDB 7.0.15b (5.1.44-ndb-7.0.15b) * *Bugs fixed:* * *Cluster API*: The value of an internal constant used in the implementation of the `NdbOperation' and `NdbScanOperation' classes caused MySQL Cluster NDB 7.0 NDB API applications compiled against MySQL Cluster NDB 7.0.14 or earlier to fail when run with MySQL Cluster 7.0.15, and MySQL Cluster NDB 7.1 NDB API applications compiled against MySQL Cluster NDB 7.1.3 or earlier to break when used with MySQL Cluster 7.1.4. (Bug #54516) *Changes in MySQL Cluster NDB 7.0.14 (5.1.44-ndb-7.0.14) * *Functionality added or changed:* * *Cluster API*: It is now possible to determine, using the *Note `ndb_desc': mysql-cluster-programs-ndb-desc. utility or the NDB API, which data nodes contain replicas of which partitions. For *Note `ndb_desc': mysql-cluster-programs-ndb-desc, a new `--extra-node-info' option is added to cause this information to be included in its output. A new method `Table::getFragmentNodes()' is added to the NDB API for obtaining this information programmatically. (Bug #51184) * *Cluster API*: It is now possible to determine, using the *Note `ndb_desc': mysql-cluster-programs-ndb-desc. utility or the NDB API, which data nodes contain replicas of which partitions. For *Note `ndb_desc': mysql-cluster-programs-ndb-desc, a new `--extra-node-info' option is added to cause this information to be included in its output. A new method `Table::getFragmentNodes()' is added to the NDB API for obtaining this information programmatically. (Bug #51184) * Formerly, the `REPORT' and `DUMP' commands returned output to all *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. clients connected to the same MySQL Cluster. Now, these commands return their output only to the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client that actually issued the command. (Bug #40865) *Bugs fixed:* * *Cluster API*: *Incompatible Change*: The default behavior of the NDB API Event API has changed as follows: Previously, when creating an `Event', DDL operations (alter and drop operations on tables) were automatically reported on any event operation that used this event, but as a result of this change, this is no longer the case. Instead, you must now invoke the event's `setReport()' method, with the new `EventReport' value `ER_DDL', to get this behavior. For existing NDB API applications where you wish to retain the old behavior, you must update the code as indicated previously, then recompile, following an upgrade. Otherwise, DDL operations are no longer reported after upgrading `libndbnclient'. For more information, see The `Event::EventReport' Type (http://dev.mysql.com/doc/ndbapi/en/ndb-event-types.html#ndb-event-eventreport), and `Event::setReport()' (http://dev.mysql.com/doc/ndbapi/en/ndb-event-methods.html#ndb-event-setreport). (Bug #53308) * *Cluster API*: *Incompatible Change*: The default behavior of the NDB API Event API has changed as follows: Previously, when creating an `Event', DDL operations (alter and drop operations on tables) were automatically reported on any event operation that used this event, but as a result of this change, this is no longer the case. Instead, you must now invoke the event's `setReport()' method, with the new `EventReport' value `ER_DDL', to get this behavior. For existing NDB API applications where you wish to retain the old behavior, you must update the code as indicated previously, then recompile, following an upgrade. Otherwise, DDL operations are no longer reported after upgrading `libndbnclient'. For more information, see The `Event::EventReport' Type (http://dev.mysql.com/doc/ndbapi/en/ndb-event-types.html#ndb-event-eventreport), and `Event::setReport()' (http://dev.mysql.com/doc/ndbapi/en/ndb-event-methods.html#ndb-event-setreport). (Bug #53308) * If a node or cluster failure occurred while *Note `mysqld': mysqld. was scanning the `ndb.ndb_schema' table (which it does when attempting to connect to the cluster), insufficient error handling could lead to a crash by *Note `mysqld': mysqld. in certain cases. This could happen in a MySQL Cluster with a great many tables, when trying to restart data nodes while one or more *Note `mysqld': mysqld. processes were restarting. (Bug #52325) * In MySQL Cluster NDB 7.0 and later, DDL operations are performed within schema transactions; the NDB kernel code for starting a schema transaction checks that all data nodes are at the same version before permitting a schema transaction to start. However, when a version mismatch was detected, the client was not actually informed of this problem, which caused the client to hang. (Bug #52228) * After running a mixed series of node and system restarts, a system restart could hang or fail altogether. This was caused by setting the value of the newest completed global checkpoint too low for a data node performing a node restart, which led to the node reporting incorrect GCI intervals for its first local checkpoint. (Bug #52217) * When performing a complex mix of node restarts and system restarts, the node that was elected as master sometimes required optimized node recovery due to missing `REDO' information. When this happened, the node crashed with `Failure to recreate object ... during restart, error 721' (because the `DBDICT' restart code was run twice). Now when this occurs, node takeover is executed immediately, rather than being made to wait until the remaining data nodes have started. (Bug #52135) See also Bug #48436. * The internal variable `ndb_new_handler', which is no longer used, has been removed. (Bug #51858) * `ha_ndbcluster.cc' was not compiled with the same `SAFEMALLOC' and `SAFE_MUTEX' flags as the MySQL Server. (Bug #51857) * When debug compiling MySQL Cluster on Windows, the mysys library was not compiled with -DSAFEMALLOC and -DSAFE_MUTEX, due to the fact that my_socket.c was misnamed as my_socket.cc. (Bug #51856) * The redo log protects itself from being filled up by periodically checking how much space remains free. If insufficient redo log space is available, it sets the state `TAIL_PROBLEM' which results in transactions being aborted with error code 410 (`out of redo log'). However, this state was not set following a node restart, which meant that if a data node had insufficient redo log space following a node restart, it could crash a short time later with `Fatal error due to end of REDO log'. Now, this space is checked during node restarts. (Bug #51723) * Restoring a MySQL Cluster backup between platforms having different endianness failed when also restoring metadata and the backup contained a hashmap not already present in the database being restored to. This issue was discovered when trying to restore a backup made on Solaris/SPARC to a MySQL Cluster running on Solaris/x86, but could conceivably occur in other cases where the endianness of the platform on which the backup was taken differed from that of the platform being restored to. (Bug #51432) * The output of the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client `REPORT BACKUPSTATUS' command could sometimes contain errors due to uninitialized data. (Bug #51316) * A `GROUP BY' query against *Note `NDB': mysql-cluster. tables sometimes did not use any indexes unless the query included a `FORCE INDEX' option. With this fix, indexes are used by such queries (where otherwise possible) even when `FORCE INDEX' is not specified. (Bug #50736) * The following issues were fixed in the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client `REPORT MEMORYUSAGE' command: * The client sometimes inserted extra `ndb_mgm>' prompts within the output. * For data nodes running *Note `ndbmtd': mysql-cluster-programs-ndbmtd, `IndexMemory' was reported before `DataMemory'. * In addition, for data nodes running *Note `ndbmtd': mysql-cluster-programs-ndbmtd, there were multiple `IndexMemory' entries listed in the output. (Bug #50196) * Issuing a command in the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client after it had lost its connection to the management server could cause the client to crash. (Bug #49219) * The *Note `mysql': mysql. client `system' command did not work properly. This issue was only known to affect the version of the *Note `mysql': mysql. client that was included with MySQL Cluster NDB 7.0 and MySQL Cluster NDB 7.1 releases. (Bug #48574) * The internal `ErrorReporter::formatMessage()' method could in some cases cause a buffer overflow. (Bug #47120) * Information about several management client commands was missing from (that is, truncated in) the output of the `HELP' command. (Bug #46114) * The *Note `ndb_print_backup_file': mysql-cluster-programs-ndb-print-backup-file. utility failed to function, due to a previous internal change in the NDB code. (Bug #41512, Bug #48673) * When the `MemReportFrequency' configuration parameter was set in `config.ini', the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client `REPORT MEMORYUSAGE' command printed its output multiple times. (Bug #37632) * *Note `ndb_mgm -e "... REPORT ..."': mysql-cluster-programs-ndb-mgm. did not write any output to `stdout'. The fix for this issue also prevents the cluster log from being flooded with `INFO' messages when `DataMemory' usage reaches 100%, and insures that when the usage is decreased, an appropriate message is written to the cluster log. (Bug #31542, Bug #44183, Bug #49782) * *Disk Data*: Inserts of blob column values into a MySQL Cluster Disk Data table that exhausted the tablespace resulted in misleading `no such tuple' error messages rather than the expected error `tablespace full'. This issue appeared similar to Bug#48113, but had a different underlying cause. (Bug #52201) * *Disk Data*: The error message returned after atttempting to execute *Note `ALTER LOGFILE GROUP': alter-logfile-group. on an nonexistent logfile group did not indicate the reason for the failure. (Bug #51111) * *Disk Data*: DDL operations on Disk Data tables having a relatively small `UNDO_BUFFER_SIZE' could fail unexpectedly. * *Cluster API*: When reading blob data with lock mode `LM_SimpleRead', the lock was not upgraded as expected. (Bug #51034) * *Cluster API*: A number of issues were corrected in the NDB API coding examples found in the `storage/ndb/ndbapi-examples' directory in the MySQL Cluster source tree. These included possible endless recursion in `ndbapi_scan.cpp' as well as problems running some of the examples on systems using Windows or Mac OS X due to the lettercase used for some table names. (Bug #30552, Bug #30737) *Changes in MySQL Cluster NDB 7.0.13 (5.1.41-ndb-7.0.13) * *Functionality added or changed:* * A new configuration parameter `HeartbeatThreadPriority' makes it possible to select between a first-in, first-out or round-round scheduling policy for management node and API node heartbeat threads, as well as to set the priority of these threads. See *Note mysql-cluster-mgm-definition::, or *Note mysql-cluster-api-definition::, for more information. (Bug #49617) * Start phases are now written to the data node logs. (Bug #49158) * *Disk Data*: The *Note `ndb_desc': mysql-cluster-programs-ndb-desc. utility can now show the extent space and free extent space for subordinate *Note `BLOB': blob. and *Note `TEXT': blob. columns (stored in hidden `BLOB' tables by NDB). A `--blob-info' option has been added for this program that causes *Note `ndb_desc': mysql-cluster-programs-ndb-desc. to generate a report for each subordinate `BLOB' table. For more information, see *Note mysql-cluster-programs-ndb-desc::. (Bug #50599) *Bugs fixed:* * When performing a system restart of a MySQL Cluster where multi-threaded data nodes were in use, there was a slight risk that the restart would hang due to incorrect serialization of signals passed between LQH instances and proxies; some signals were sent using a proxy, and others directly, which meant that the order in which they were sent and received could not be guaranteed. If signals arrived in the wrong order, this could cause one or more data nodes to hang. Now all signals that need to be sent and received in the same order are sent using the same path. (Bug #51645) * When one or more data nodes read their LCPs and applied undo logs significantly faster than others, this could lead to a race condition causing system restarts of data nodes to hang. This could most often occur when using both *Note `ndbd': mysql-cluster-programs-ndbd. and *Note `ndbmtd': mysql-cluster-programs-ndbmtd. processes for the data nodes. (Bug #51644) * When deciding how to divide the REDO log, the `DBDIH' kernel block saved more than was needed to restore the previous local checkpoint, which could cause REDO log space to be exhausted prematurely (`NDB' error 410). (Bug #51547) * DML operations can fail with `NDB' error 1220 (`REDO log files overloaded...') if the opening and closing of REDO log files takes too much time. If this occurred as a GCI marker was being written in the REDO log while REDO log file 0 was being opened or closed, the error could persist until a GCP stop was encountered. This issue could be triggered when there was insufficient REDO log space (for example, with configuration parameter settings `NoOfFragmentLogFiles = 6' and `FragmentLogFileSize = 6M') with a load including a very high number of updates. (Bug #51512) See also Bug #20904. * A side effect of the *Note `ndb_restore': mysql-cluster-programs-ndb-restore. `--disable-indexes' and `--rebuild-indexes' options is to change the schema versions of indexes. When a *Note `mysqld': mysqld. later tried to drop a table that had been restored from backup using one or both of these options, the server failed to detect these changed indexes. This caused the table to be dropped, but the indexes to be left behind, leading to problems with subsequent backup and restore operations. (Bug #51374) * *Note `ndb_restore': mysql-cluster-programs-ndb-restore. crashed while trying to restore a corrupted backup, due to missing error handling. (Bug #51223) * The *Note `ndb_restore': mysql-cluster-programs-ndb-restore. message `Successfully created index `PRIMARY`...' was directed to `stderr' instead of `stdout'. (Bug #51037) * When using `NoOfReplicas' equal to 1 or 2, if data nodes from one node group were restarted 256 times and applications were running traffic such that it would encounter *Note `NDB': mysql-cluster. error 1204 (`Temporary failure, distribution changed'), the live node in the node group would crash, causing the cluster to crash as well. The crash occurred only when the error was encountered on the 256th restart; having the error on any previous or subsequent restart did not cause any problems. (Bug #50930) * Replication of a MySQL Cluster using multi-threaded data nodes could fail with forced shutdown of some data nodes due to the fact that *Note `ndbmtd': mysql-cluster-programs-ndbmtd. exhausted `LongMessageBuffer' much more quickly than *Note `ndbd': mysql-cluster-programs-ndbd. After this fix, passing of replication data between the `DBTUP' and `SUMA' NDB kernel blocks is done using `DataMemory' rather than `LongMessageBuffer'. Until you can upgrade, you may be able to work around this issue by increasing the `LongMessageBuffer' setting; doubling the default should be sufficient in most cases. (Bug #46914) * A *Note `SELECT': select. requiring a sort could fail with the error `Can't find record in 'TABLE'' when run concurrently with a *Note `DELETE': delete. from the same table. (Bug #45687) * *Cluster API*: An issue internal to *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. could cause problems when trying to start a large number of data nodes at the same time. (Bug #51273) See also Bug #51310. *Changes in MySQL Cluster NDB 7.0.12 (5.1.41-ndb-7.0.12) * *Functionality added or changed:* * Numeric codes used in management server status update messages in the cluster logs have been replaced with text descriptions. (Bug #49627) See also Bug #44248. *Bugs fixed:* * *Note `ndbmtd': mysql-cluster-programs-ndbmtd. started on a single-core machine could sometimes fail with a `Job Buffer Full' error when `MaxNoOfExecutionThreads' was set greater than `LockExecuteThreadToCPU'. Now a warning is logged when this occurs. (Bug #50582) * When a primary key lookup on an *Note `NDB': mysql-cluster. table containing one or more *Note `BLOB': blob. columns was executed in a transaction, a shared lock on any blob tables used by the *Note `NDB': mysql-cluster. table was held for the duration of the transaction. (This did not occur for indexed or non-indexed `WHERE' conditions.) Now in such cases, the lock is released after all *Note `BLOB': blob. data has been read. (Bug #49190) *Changes in MySQL Cluster NDB 7.0.11 (5.1.41-ndb-7.0.11) * *Functionality added or changed:* * *Important Change*: The maximum permitted value of the `ndb_autoincrement_prefetch_sz' system variable has been increased from 256 to 65536. (Bug #50621) * Added multi-threaded ordered index building capability during system restarts or node restarts, controlled by the `BuildIndexThreads' data node configuration parameter (also introduced in this release). *Bugs fixed:* * Initial start of partitioned nodes did not work correctly. This issue was observed in MySQL Cluster NDB 7.0 only. (Bug #50661) * The `CREATE NODEGROUP' client command in *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. could sometimes cause the forced shutdown of a data node. (Bug #50594) * Local query handler information was not reported or written to the cluster log correctly. This issue is thought to have been introduced in MySQL Cluster NDB 7.0.10. (Bug #50467) * Online upgrades from MySQL Cluster NDB 7.0.9b to MySQL Cluster NDB 7.0.10 did not work correctly. Current MySQL Cluster NDB 7.0 users should upgrade directly to MySQL Cluster NDB 7.0.11 or later. This issue is not known to have affected MySQL Cluster NDB 6.3, and it should be possible to upgrade from MySQL Cluster NDB 6.3 to MySQL Cluster NDB 7.0.10 without problems. See *Note mysql-cluster-upgrade-downgrade-compatibility-6.x::, for more information. (Bug #50433) * Dropping unique indexes in parallel while they were in use could cause node and cluster failures. (Bug #50118) * When attempting to join a running cluster whose management server had been started with the `--nowait-nodes' option and having SQL nodes with dynamically allocated node IDs, a second management server failed with spurious `INTERNAL ERROR: Found dynamic ports with value in config...' error messages. (Bug #49807) * When setting the `LockPagesInMainMemory' configuration parameter failed, only the error `Failed to memlock pages...' was returned. Now in such cases the operating system's error code is also returned. (Bug #49724) * If a query on an *Note `NDB': mysql-cluster. table compared a constant string value to a column, and the length of the string was greater than that of the column, condition pushdown did not work correctly. (The string was truncated to fit the column length before being pushed down.) Now in such cases, the condition is no longer pushed down. (Bug #49459) * *Note `ndbmtd': mysql-cluster-programs-ndbmtd. was not built on Windows (`CMake' did not provide a build target for it). (Bug #49325) * Performing intensive inserts and deletes in parallel with a high scan load could a data node crashes due to a failure in the `DBACC' kernel block. This was because checking for when to perform bucket splits or merges considered the first 4 scans only. (Bug #48700) * During Start Phases 1 and 2, the `STATUS' command sometimes (falsely) returned `Not Connected' for data nodes running *Note `ndbmtd': mysql-cluster-programs-ndbmtd. (Bug #47818) * When performing a *Note `DELETE': delete. that included a left join from an *Note `NDB': mysql-cluster. table, only the first matching row was deleted. (Bug #47054) * Under some circumstances, the `DBTC' kernel block could send an excessive number of commit and completion messages which could lead to a the job buffer filling up and node failure. This was especially likely to occur when using *Note `ndbmtd': mysql-cluster-programs-ndbmtd. with a single data node. (Bug #45989) * *Note `mysqld': mysqld. could sometimes crash during a commit while trying to handle NDB Error 4028 `Node failure caused abort of transaction'. (Bug #38577) * When setting `LockPagesInMainMemory', the stated memory was not allocated when the node was started, but rather only when the memory was used by the data node process for other reasons. (Bug #37430) * Trying to insert more rows than would fit into an `NDB' table caused data nodes to crash. Now in such situations, the insert fails gracefully with error 633 `Table fragment hash index has reached maximum possible size'. (Bug #34348) *Changes in MySQL Cluster NDB 7.0.10 (5.1.39-ndb-7.0.10) * *Functionality added or changed:* * Added the *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. `--nowait-nodes' option, which permits a cluster that is configured to use multiple management servers to be started using fewer than the number configured. This is most likely to be useful when a cluster is configured with two management servers and you wish to start the cluster using only one of them. See *Note mysql-cluster-programs-ndb-mgmd::, for more information. (Bug #48669) * This enhanced functionality is supported for upgrades from MySQL Cluster NDB 6.3 when the *Note `NDB': mysql-cluster. engine version is 6.3.29 or later. (Bug #48528, Bug #49163) * The output from *Note `ndb_config': mysql-cluster-programs-ndb-config. `--configinfo' `--xml' now indicates, for each configuration parameter, the following restart type information: * Whether a system restart or a node restart is required when resetting that parameter; * Whether cluster nodes need to be restarted using the `--initial' option when resetting the parameter. (Bug #47366) *Bugs fixed:* * Node takeover during a system restart occurs when the REDO log for one or more data nodes is out of date, so that a node restart is invoked for that node or those nodes. If this happens while a *Note `mysqld': mysqld. process is attached to the cluster as an SQL node, the *Note `mysqld': mysqld. takes a global schema lock (a row lock), while trying to set up cluster-internal replication. However, this setup process could fail, causing the global schema lock to be held for an excessive length of time, which made the node restart hang as well. As a result, the mysqld failed to set up cluster-internal replication, which led to tables being read only, and caused one node to hang during the restart. *Note*: This issue could actually occur in MySQL Cluster NDB 7.0 only, but the fix was also applied MySQL Cluster NDB 6.3, in order to keep the two codebases in alignment. (Bug #49560) * Sending `SIGHUP' to a *Note `mysqld': mysqld. running with the `--ndbcluster' and `--log-bin' options caused the process to crash instead of refreshing its log files. (Bug #49515) * If the master data node receiving a request from a newly-started API or data node for a node ID died before the request has been handled, the management server waited (and kept a mutex) until all handling of this node failure was complete before responding to any other connections, instead of responding to other connections as soon as it was informed of the node failure (that is, it waited until it had received a NF_COMPLETEREP signal rather than a NODE_FAILREP signal). On visible effect of this misbehavior was that it caused management client commands such as SHOW and ALL STATUS to respond with unnecessary slowness in such circumstances. (Bug #49207) * Attempting to create more than 11435 tables failed with Error 306 (`Out of fragment records in DIH'). (Bug #49156) * When evaluating the options `--include-databases', `--include-tables', `--exclude-databases', and `--exclude-tables', the *Note `ndb_restore': mysql-cluster-programs-ndb-restore. program overwrote the result of the database-level options with the result of the table-level options rather than merging these results together, sometimes leading to unexpected and unpredictable results. As part of the fix for this problem, the semantics of these options have been clarified; because of this, the rules governing their evaluation have changed slightly. These changes be summed up as follows: * All `--include-*' and `--exclude-*' options are now evaluated from right to left in the order in which they are passed to *Note `ndb_restore': mysql-cluster-programs-ndb-restore. * All `--include-*' and `--exclude-*' options are now cumulative. * In the event of a conflict, the first (rightmost) option takes precedence. For more detailed information and examples, see *Note mysql-cluster-programs-ndb-restore::. (Bug #48907) * When performing tasks that generated large amounts of I/O (such as when using *Note `ndb_restore': mysql-cluster-programs-ndb-restore.), an internal memory buffer could overflow, causing data nodes to fail with signal 6. Subsequent analysis showed that this buffer was not actually required, so this fix removes it. (Bug #48861) * Exhaustion of send buffer memory or long signal memory caused data nodes to crash. Now an appropriate error message is provided instead when this situation occurs. (Bug #48852) * In some situations, when it was not possible for an SQL node to start a schema transaction (necessary, for instance, as part of an online *Note `ALTER TABLE': alter-table.), *Note `NDBCLUSTER': mysql-cluster. did not correctly indicate the error to the MySQL server, which led *Note `mysqld': mysqld. to crash. (Bug #48841) * Under certain conditions, accounting of the number of free scan records in the local query handler could be incorrect, so that during node recovery or a local checkpoint operations, the LQH could find itself lacking a scan record that is expected to find, causing the node to crash. (Bug #48697) See also Bug #48564. * The creation of an ordered index on a table undergoing DDL operations could cause a data node crash under certain timing-dependent conditions. (Bug #48604) * During an LCP master takeover, when the newly elected master did not receive a `COPY_GCI' LCP protocol message but other nodes participating in the local checkpoint had received one, the new master could use an uninitialized variable, which caused it to crash. (Bug #48584) * When running many parallel scans, a local checkpoint (which performs a scan internally) could find itself not getting a scan record, which led to a data node crash. Now an extra scan record is reserved for this purpose, and a problem with obtaining the scan record returns an appropriate error (error code 489, `Too many active scans'). (Bug #48564) * During a node restart, logging was enabled on a per-fragment basis as the copying of each fragment was completed but local checkpoints were not enabled until all fragments were copied, making it possible to run out of redo log file space (*Note `NDB': mysql-cluster. error code 410) before the restart was complete. Now logging is enabled only after all fragments has been copied, just prior to enabling local checkpoints. (Bug #48474) * When using very large transactions containing many inserts, *Note `ndbmtd': mysql-cluster-programs-ndbmtd. could fail with Signal 11 without an easily detectable reason, due to an internal variable being unitialized in the event that the `LongMessageBuffer' was overloaded. Now, the variable is initialized in such cases, avoiding the crash, and an appropriate error message is generated. (Bug #48441) See also Bug #46914. * A data node crashing while restarting, followed by a system restart could lead to incorrect handling of redo log metadata, causing the system restart to fail with `Error while reading REDO log'. (Bug #48436) * Starting a *Note `mysqld': mysqld. process with `--ndb-nodeid' (either as a command-line option or by assigning it a value in `my.cnf') caused the *Note `mysqld': mysqld. to get only the corresponding connection from the `[mysqld]' section in the `config.ini' file having the matching ID, even when connection pooling was enabled (that is, when the *Note `mysqld': mysqld. process was started with `--ndb-cluster-connection-pool' set greater than 1). (Bug #48405) See also Bug #27644, Bug #38590, Bug #41592. * The configuration check that each management server runs to verify that all connected *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. processes have the same configuration could fail when a configuration change took place while this check was in progress. Now in such cases, the configuration check is rescheduled for a later time, after the change is complete. (Bug #48143) * When employing *Note `NDB': mysql-cluster. native backup to back up and restore an empty *Note `NDB': mysql-cluster. table that used a non-sequential `AUTO_INCREMENT' value, the `AUTO_INCREMENT' value was not restored correctly. (Bug #48005) * *Note `ndb_config `--xml' `--configinfo'': mysql-cluster-programs-ndb-config. now indicates that parameters belonging in the `[SCI]', `[SCI DEFAULT]', `[SHM]', and `[SHM DEFAULT]' sections of the `config.ini' file are deprecated or experimental, as appropriate. (Bug #47365) * *Note `NDB': mysql-cluster. stores blob column data in a separate, hidden table that is not accessible from MySQL. If this table was missing for some reason (such as accidental deletion of the file corresponding to the hidden table) when making a MySQL Cluster native backup, ndb_restore crashed when attempting to restore the backup. Now in such cases, ndb_restore fails with the error message `Table TABLE_NAME has blob column (COLUMN_NAME) with missing parts table in backup' instead. (Bug #47289) * In MySQL Cluster NDB 7.0, *Note `ndb_config': mysql-cluster-programs-ndb-config. and *Note `ndb_error_reporter': mysql-cluster-programs-ndb-error-reporter. were printing warnings about management and data nodes running on the same host to `stdout' instead of `stderr', as was the case in earlier MySQL Cluster release series. (Bug #44689, Bug #49160) See also Bug #25941. * *Note `DROP DATABASE': drop-database. failed when there were stale temporary *Note `NDB': mysql-cluster. tables in the database. This situation could occur if *Note `mysqld': mysqld. crashed during execution of a *Note `DROP TABLE': drop-table. statement after the table definition had been removed from *Note `NDBCLUSTER': mysql-cluster. but before the corresponding `.ndb' file had been removed from the crashed SQL node's data directory. Now, when *Note `mysqld': mysqld. executes *Note `DROP DATABASE': drop-database, it checks for these files and removes them if there are no corresponding table definitions for them found in *Note `NDBCLUSTER': mysql-cluster. (Bug #44529) * Creating an *Note `NDB': mysql-cluster. table with an excessive number of large *Note `BIT': numeric-types. columns caused the cluster to fail. Now, an attempt to create such a table is rejected with error 791 (`Too many total bits in bitfields'). (Bug #42046) See also Bug #42047. * When a long-running transaction lasting long enough to cause Error 410 (`REDO log files overloaded') was later committed or rolled back, it could happen that *Note `NDBCLUSTER': mysql-cluster. was not able to release the space used for the REDO log, so that the error condition persisted indefinitely. The most likely cause of such transactions is a bug in the application using MySQL Cluster. This fix should handle most cases where this might occur. (Bug #36500) * Deprecation and usage information obtained from *Note `ndb_config `--configinfo'': mysql-cluster-programs-ndb-config. regarding the `PortNumber' and `ServerPort' configuration parameters was improved. (Bug #24584) * *Disk Data*: When running a write-intensive workload with a very large disk page buffer cache, CPU usage approached 100% during a local checkpoint of a cluster containing Disk Data tables. (Bug #49532) * *Disk Data*: *Note `NDBCLUSTER': mysql-cluster. failed to provide a valid error message it failed to commit schema transactions during an initial start if the cluster was configured using the `InitialLogFileGroup' parameter. (Bug #48517) * *Disk Data*: In certain limited cases, it was possible when the cluster contained Disk Data tables for *Note `ndbmtd': mysql-cluster-programs-ndbmtd. to crash during a system restart. (Bug #48498) See also Bug #47832. * *Disk Data*: Repeatedly creating and then dropping Disk Data tables could eventually lead to data node failures. (Bug #45794, Bug #48910) * *Disk Data*: When a crash occurs due to a problem in Disk Data code, the currently active page list is printed to `stdout' (that is, in one or more `ndb_NODEID_out.log' files). One of these lists could contain an endless loop; this caused a printout that was effectively never-ending. Now in such cases, a maximum of 512 entries is printed from each list. (Bug #42431) * *Disk Data*: When the `FileSystemPathUndoFiles' configuration parameter was set to an non-existent path, the data nodes shut down with the generic error code 2341 (`Internal program error'). Now in such cases, the error reported is error 2815 (`File not found'). * *Cluster API*: When a DML operation failed due to a uniqueness violation on an *Note `NDB': mysql-cluster. table having more than one unique index, it was difficult to determine which constraint caused the failure; it was necessary to obtain an `NdbError' object, then decode its `details' property, which in could lead to memory management issues in application code. To help solve this problem, a new API method `Ndb::getNdbErrorDetail()' is added, providing a well-formatted string containing more precise information about the index that caused the unque constraint violation. The following additional changes are also made in the NDB API: * Use of `NdbError.details' is now deprecated in favor of the new method. * The `NdbDictionary::listObjects()' method has been modified to provide more information. For more information, see `Ndb::getNdbErrorDetail()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndb-methods.html#ndb-ndb-getndberrordetail), The `NdbError' Structure (http://dev.mysql.com/doc/ndbapi/en/ndb-ndberror.html#ndb-ndberror), and `Dictionary::listObjects()' (http://dev.mysql.com/doc/ndbapi/en/ndb-dictionary-methods.html#ndb-dictionary-listobjects). (Bug #48851) * *Cluster API*: When using blobs, calling `getBlobHandle()' requires the full key to have been set using `equal()', because `getBlobHandle()' must access the key for adding blob table operations. However, if `getBlobHandle()' was called without first setting all parts of the primary key, the application using it crashed. Now, an appropriate error code is returned instead. (Bug #28116, Bug #48973) *Changes in MySQL Cluster NDB 7.0.9a (5.1.39-ndb-7.0.9a) * *Bugs fixed:* * When the combined length of all names of tables using the *Note `NDB': mysql-cluster. storage engine was greater than or equal to 1024 bytes, issuing the `START BACKUP' command in the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client caused the cluster to crash. (Bug #48531) *Changes in MySQL Cluster NDB 7.0.8a (5.1.37-ndb-7.0.8a) * *Bugs fixed:* * The disconnection of an API or SQL node having a node ID greater than 49 caused a forced shutdown of the cluster. (Bug #47844) * The error message text for *Note `NDB': mysql-cluster. error code 410 (`REDO log files overloaded...') was truncated. (Bug #23662) *Changes in MySQL Cluster NDB 7.0.7 (5.1.35-ndb-7.0.7) * *Functionality added or changed:* * *Important Change*: The default value of the `DiskIOThreadPool' data node configuration parameter has changed from 8 to 2. * On Solaris platforms, the MySQL Cluster management server and NDB API applications now use `CLOCK_REALTIME' as the default clock. (Bug #46183) * Formerly, node IDs were represented in the cluster log using a complex hexadecimal/binary encoding scheme. Now, node IDs are reported in the cluster log using numbers in standard decimal notation. (Bug #44248) * A new option `--exclude-missing-columns' has been added for the *Note `ndb_restore': mysql-cluster-programs-ndb-restore. program. In the event that any tables in the database or databases being restored to have fewer columns than the same-named tables in the backup, the extra columns in the backup's version of the tables are ignored. For more information, see *Note mysql-cluster-programs-ndb-restore::. (Bug #43139) * *Note*: This issue, originally resolved in MySQL 5.1.16, re-occurred due to a later (unrelated) change. The fix has been re-applied. (Bug #25984) * Previously, it was possible to disable arbitration only by setting `ArbitrationRank' to 0 on all management and API nodes. A new data node configuration parameter `Arbitration' simplifies this task; to disable arbitration, you can now use `Arbitration = Disabled' in the `[ndbd default]' section of the `config.ini' file. It is now also possible to configure arbitration in such a way that the cluster waits until the time determined by `ArbitrationTimeout' passes for an external manager to perform arbitration instead of handling it internally. This can be done by setting `Arbitration = WaitExternal' in the `[ndbd default]' section of the `config.ini' file. The default value for the Arbitration parameter is `Default', which permits arbitration to proceed normally, as determined by the `ArbitrationRank' settings for the management and API nodes. For more information, see *Note mysql-cluster-ndbd-definition::. *Bugs fixed:* * *Packaging*: The `pkg' installer for MySQL Cluster on Solaris did not perform a complete installation due to an invalid directory reference in the postinstall script. (Bug #41998) * The output from *Note `ndb_config': mysql-cluster-programs-ndb-config. `--configinfo' `--xml' contained quote characters (`"') within quoted XML attributes, causing it to be not well-formed. (Bug #46891) * When using multi-threaded data node processes (*Note `ndbmtd': mysql-cluster-programs-ndbmtd.), it was possible for LQH threads to continue running even after all *Note `NDB': mysql-cluster. tables had been dropped. This meant that dropping the last remaining *Note `NDB': mysql-cluster. table during a local checkpoint could cause multi-threaded data nodes to fail. (Bug #46890) * During a global checkpoint, LQH threads could run unevenly, causing a circular buffer oveflow by the Subscription Manager, which led to data node failure. (Bug #46782) See also Bug #46123, Bug #46723, Bug #45612. * Restarting the cluster following a local checkpoint and an online *Note `ALTER TABLE': alter-table. on a non-empty table caused data nodes to crash. (Bug #46651) * A combination of index creation and drop operations (or creating and dropping tables having indexes) with node and system restarts could lead to a crash. (Bug #46552) * Following an upgrade from MySQL Cluster NDB 6.3.x to MySQL Cluster NDB 7.0.6, DDL and backup operations failed. (Bug #46494, Bug #46563) * Full table scans failed to execute when the cluster contained more than 21 table fragments. *Note*: The number of table fragments in the cluster can be calculated as the number of data nodes, times 8 (that is, times the value of the internal constant `MAX_FRAG_PER_NODE'), divided by the number of replicas. Thus, when `NoOfReplicas = 1' at least 3 data nodes were required to trigger this issue, and when `NoOfReplicas = 2' at least 4 data nodes were required to do so. (Bug #46490) * Killing MySQL Cluster nodes immediately following a local checkpoint could lead to a crash of the cluster when later attempting to perform a system restart. The exact sequence of events causing this issue was as follows: 1. Local checkpoint occurs. 2. Immediately following the LCP, kill the master data node. 3. Kill the remaining data nodes within a few seconds of killing the master. 4. Attempt to restart the cluster. (Bug #46412) * Creating an index when the cluster had run out of table records could cause data nodes to crash. (Bug #46295) * Ending a line in the `config.ini' file with an extra semicolon character (`;') caused reading the file to fail with a parsing error. (Bug #46242) * When combining an index scan and a delete with a primary key delete, the index scan and delete failed to initialize a flag properly. This could in rare circumstances cause a data node to crash. (Bug #46069) * *Note `OPTIMIZE TABLE': optimize-table. on an *Note `NDB': mysql-cluster. table could in some cases cause SQL and data nodes to crash. This issue was observed with both *Note `ndbd': mysql-cluster-programs-ndbd. and *Note `ndbmtd': mysql-cluster-programs-ndbmtd. (Bug #45971) * The `AutoReconnect' configuration parameter for API nodes (including SQL nodes) has been added. This is intended to prevent API nodes from re-using allocated node IDs during cluster restarts. For more information, see *Note mysql-cluster-api-definition::. This fix also introduces two new methods of the NDB API `Ndb_cluster_connection' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndb-cluster-connection.html#ndb-ndb-cluster-connection) class: `set_auto_reconnect()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndb-cluster-connection-methods.html#ndb-ndb-cluster-connection-set-auto-reconnect) and `get_auto_reconnect()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndb-cluster-connection-methods.html#ndb-ndb-cluster-connection-get-auto-reconnect). (Bug #45921) * DML statements run during an upgrade from MySQL Cluster NDB 6.3 to NDB 7.0 were not handled correctly. (Bug #45917) * On Windows, the internal `basestring_vsprintf()' function did not return a POSIX-compliant value as expected, causing the management server to crash when trying to start a MySQL Cluster with more than 4 data nodes. (Bug #45733) * The signals used by *Note `ndb_restore': mysql-cluster-programs-ndb-restore. to send progress information about backups to the cluster log accessed the cluster transporter without using any locks. Because of this, it was theoretically possible that these signals could be interefered with by heartbeat signals if both were sent at the same time, causing the *Note `ndb_restore': mysql-cluster-programs-ndb-restore. messages to be corrupted. (Bug #45646) * Due to changes in the way that *Note `NDBCLUSTER': mysql-cluster. handles schema changes (implementation of schema transactions) in MySQL Cluster NDB 7.0, it was not possible to create MySQL Cluster tables having more than 16 indexes using a single *Note `CREATE TABLE': create-table. statement. This issue occurs only in MySQL Cluster NDB 7.0 releases prior to 7.0.7 (including releases numbered NDB 6.4.x). If you are not yet able to upgrade from an earlier MySQL Cluster NDB 7.0 release, you can work around this problem by creating the table without any indexes, then adding the indexes using a separate *Note `CREATE INDEX': create-index. statement for each index. (Bug #45525) * `storage/ndb/src/common/util/CMakeLists.txt' did not build the `BaseString-t' test program for Windows as the equivalent `storage/ndb/src/common/util/Makefile.am' does when building MySQL Cluster on Unix platforms. (Bug #45099) * Problems could arise when using *Note `VARCHAR': char. columns whose size was greater than 341 characters and which used the `utf8_unicode_ci' collation. In some cases, this combination of conditions could cause certain queries and *Note `OPTIMIZE TABLE': optimize-table. statements to crash *Note `mysqld': mysqld. (Bug #45053) * The warning message `Possible bug in Dbdih::execBLOCK_COMMIT_ORD ...' could sometimes appear in the cluster log. This warning is obsolete, and has been removed. (Bug #44563) * Debugging code causing *Note `ndbd': mysql-cluster-programs-ndbd. to use file compression on NTFS file systems failed with an error. (The code was removed.) This issue affected debug builds of MySQL Cluster on Windows platforms only. (Bug #44418) * *Note `ALTER TABLE REORGANIZE PARTITION': alter-table. could fail with Error 741 (`Unsupported alter table') if the appropriate hash-map was not present. This could occur when adding nodes online; for example, when going from 2 data nodes to 3 data nodes with `NoOfReplicas=1', or from 4 data nodes to 6 data nodes with `NoOfReplicas=2'. (Bug #44301) * Previously, a `GCP STOP' event was written to the cluster log as an `INFO' event. Now it is logged as a `WARNING' event instead. (Bug #43853) * In some cases, *Note `OPTIMIZE TABLE': optimize-table. on an *Note `NDB': mysql-cluster. table did not free any `DataMemory'. (Bug #43683) * If the cluster crashed during the execution of a *Note `CREATE LOGFILE GROUP': create-logfile-group. statement, the cluster could not be restarted afterward. (Bug #36702) See also Bug #34102. * *Disk Data*: *Partitioning*: An *Note `NDB': mysql-cluster. table created with a very large value for the `MAX_ROWS' option could--if this table was dropped and a new table with fewer partitions, but having the same table ID, was created--cause *Note `ndbd': mysql-cluster-programs-ndbd. to crash when performing a system restart. This was because the server attempted to examine each partition whether or not it actually existed. (Bug #45154) See also Bug #58638. * *Disk Data*: If the value set in the `config.ini' file for `FileSystemPathDD', `FileSystemPathDataFiles', or `FileSystemPathUndoFiles' was identical to the value set for `FileSystemPath', that parameter was ignored when starting the data node with `--initial' option. As a result, the Disk Data files in the corresponding directory were not removed when performing an initial start of the affected data node or data nodes. (Bug #46243) *Changes in MySQL Cluster NDB 7.0.6 (5.1.34-ndb-7.0.6) * *Functionality added or changed:* * The *Note `ndb_config': mysql-cluster-programs-ndb-config. utility program can now provide an offline dump of all MySQL Cluster configuration parameters including information such as default and permitted values, brief description, and applicable section of the `config.ini' file. A dump in text format is produced when running *Note `ndb_config': mysql-cluster-programs-ndb-config. with the new `--configinfo' option, and in XML format when the options `--configinfo --xml' are used together. For more information and examples, see *Note mysql-cluster-programs-ndb-config::. *Bugs fixed:* * *Important Change*: *Partitioning*: User-defined partitioning of an *Note `NDBCLUSTER': mysql-cluster. table without any primary key sometimes failed, and could cause *Note `mysqld': mysqld. to crash. Now, if you wish to create an *Note `NDBCLUSTER': mysql-cluster. table with user-defined partitioning, the table must have an explicit primary key, and all columns listed in the partitioning expression must be part of the primary key. The hidden primary key used by the *Note `NDBCLUSTER': mysql-cluster. storage engine is not sufficient for this purpose. However, if the list of columns is empty (that is, the table is defined using `PARTITION BY [LINEAR] KEY()'), then no explicit primary key is required. This change does not effect the partitioning of tables using any storage engine other than *Note `NDBCLUSTER': mysql-cluster. (Bug #40709) * *Important Change*: Previously, the configuration parameter `NoOfReplicas' had no default value. Now the default for `NoOfReplicas' is 2, which is the recommended value in most settings. (Bug #44746) * *Important Note*: It was not possible to perform an online upgrade from any MySQL Cluster NDB 6.x release to MySQL Cluster NDB 7.0.5 or any to earlier MySQL Cluster NDB 7.0 release. With this fix, it is possible in MySQL Cluster NDB 7.0.6 and later to perform online upgrades from MySQL Cluster NDB 6.3.8 and later MySQL Cluster NDB 6.3 releases, or from MySQL Cluster NDB 7.0.5 or later MySQL Cluster NDB 7.0 releases. Online upgrades to MySQL Cluster NDB 7.0 releases previous to MySQL Cluster NDB 7.0.6 from earlier MySQL Cluster releases remain unsupported; online upgrades from MySQL Cluster NDB 7.0 releases previous to MySQL Cluster NDB 7.0.5 (including NDB 6.4.x beta releases) to later MySQL Cluster NDB 7.0 releases also remain unsupported. (Bug #44294) * An internal NDB API buffer was not properly initialized. (Bug #44977) * When a data node had written its GCI marker to the first page of a megabyte, and that node was later killed during restart after having processed that page (marker) but before completing a LCP, the data node could fail with file system errors. (Bug #44952) See also Bug #42564, Bug #44291. * When restarting a data nodes, management and API nodes reconnecting to it failed to re-use existing ports that had already been dynamically allocated for communications with that data node. (Bug #44866) * When *Note `ndb_config': mysql-cluster-programs-ndb-config. could not find the file referenced by the `--config-file' option, it tried to read `my.cnf' instead, then failed with a misleading error message. (Bug #44846) * When a data node was down so long that its most recent local checkpoint depended on a global checkpoint that was no longer restorable, it was possible for it to be unable to use optimized node recovery when being restarted later. (Bug #44844) See also Bug #26913. * Online upgrades to MySQL Cluster NDB 7.0 from a MySQL Cluster NDB 6.3 release could fail due to changes in the handling of key lengths and unique indexes during node recovery. (Bug #44827) * *Note `ndb_config `--xml'': mysql-cluster-programs-ndb-config. did not output any entries for the `HostName' parameter. In addition, the default listed for `MaxNoOfFiles' was outside the permitted range of values. (Bug #44749) See also Bug #44685, Bug #44746. * The output of *Note `ndb_config `--xml'': mysql-cluster-programs-ndb-config. did not provide information about all sections of the configuration file. (Bug #44685) See also Bug #44746, Bug #44749. * Use of `__builtin_expect()' had the side effect that compiler warnings about misuse of `=' (assignment) instead of `==' in comparisons were lost when building in debug mode. This is no longer employed when configuring the build with the `--with-debug' option. (Bug #44570) See also Bug #44567. * Inspection of the code revealed that several assignment operators (`=') were used in place of comparison operators (`==') in `DbdihMain.cpp'. (Bug #44567) See also Bug #44570. * When using large numbers of configuration parameters, the management server took an excessive amount of time (several minutes or more) to load these from the configuration cache when starting. This problem occurred when there were more than 32 configuration parameters specified, and became progressively worse with each additional multiple of 32 configuration parameters. (Bug #44488) * Building the MySQL Cluster NDB 7.0 tree failed when using the `icc' compiler. (Bug #44310) * SSL connections to SQL nodes failed on big-endian platforms. (Bug #44295) * Signals providing node state information (`NODE_STATE_REP' and `CHANGE_NODE_STATE_REQ') were not propagated to all blocks of *Note `ndbmtd': mysql-cluster-programs-ndbmtd. This could cause the following problems: * Inconsistent redo logs when performing a graceful shutdown; * Data nodes crashing when later restarting the cluster, data nodes needing to perform node recovery during the system restart, or both. (Bug #44291) See also Bug #42564. * An NDB internal timing function did not work correctly on Windows and could cause *Note `mysqld': mysqld. to fail on some AMD processors, or when running inside a virtual machine. (Bug #44276) * It was possible for NDB API applications to insert corrupt data into the database, which could subquently lead to data node crashes. Now, stricter checking is enforced on input data for inserts and updates. (Bug #44132) * *Note `ndb_restore': mysql-cluster-programs-ndb-restore. failed when trying to restore data on a big-endian machine from a backup file created on a little-endian machine. (Bug #44069) * Repeated starting and stopping of data nodes could cause ndb_mgmd to fail. This issue was observed on Solaris/SPARC. (Bug #43974) * A number of incorrectly formatted output strings in the source code caused compiler warnings. (Bug #43878) * When trying to use a data node with an older version of the management server, the data node crashed on startup. (Bug #43699) * In some cases, data node restarts during a system restart could fail due to insufficient redo log space. (Bug #43156) * *Note `NDBCLUSTER': mysql-cluster. did not build correctly on Solaris 9 platforms. (Bug #39080) See also Bug #39036, Bug #39038. * The output of *Note `ndbd `--help'': mysql-cluster-programs-ndbd. did not provide clear information about the program's `--initial' and `--initial-start' options. (Bug #28905) * It was theoretically possible for the value of a nonexistent column to be read as `NULL', rather than causing an error. (Bug #27843) * *Disk Data*: During a checkpoint, restore points are created for both the on-disk and in-memory parts of a Disk Data table. Under certain rare conditions, the in-memory restore point could include or exclude a row that should have been in the snapshot. This would later lead to a crash during or following recovery. This issue was somewhat more likely to be encountered when using *Note `ndbmtd': mysql-cluster-programs-ndbmtd. (Bug #41915) See also Bug #47832. * *Disk Data*: This fix supercedes and improves on an earlier fix made for this bug in MySQL 5.1.18. (Bug #24521) *Changes in MySQL Cluster NDB 7.0.5 (5.1.32-ndb-7.0.5) * *Functionality added or changed:* * Two new server status variables `Ndb_scan_count' and `Ndb_pruned_scan_count' have been introduced. `Ndb_scan_count' gives the number of scans executed since the cluster was last started. `Ndb_pruned_scan_count' gives the number of scans for which *Note `NDBCLUSTER': mysql-cluster. was able to use partition pruning. Together, these variables can be used to help determine in the MySQL server whether table scans are pruned by *Note `NDBCLUSTER': mysql-cluster. (Bug #44153) *Bugs fixed:* * *Important Note*: Due to problem discovered after the code freeze for this release, it is not possible to perform an online upgrade from any MySQL Cluster NDB 6.x release to MySQL Cluster NDB 7.0.5 or any earlier MySQL Cluster NDB 7.0 release. This issue is fixed in MySQL Cluster NDB 7.0.6 and later for upgrades from MySQL Cluster NDB 6.3.8 and later MySQL Cluster NDB 6.3 releases, or from MySQL Cluster NDB 7.0.5. (Bug #44294) * *Cluster Replication*: If data node failed during an event creation operation, there was a slight risk that a surviving data node could send an invalid table reference back to NDB, causing the operation to fail with a false Error 723 (`No such table'). This could take place when a data node failed as a *Note `mysqld': mysqld. process was setting up MySQL Cluster Replication. (Bug #43754) * *Cluster API*: The following issues occurred when performing an online (rolling) upgrade of a cluster to a version of MySQL Cluster that supports configuration caching from a version that does not: 1. When using multiple management servers, after upgrading and restarting one *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd, any remaining management servers using the previous version of *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. could not synchronize their configuration data. 2. The MGM API `ndb_mgm_get_configuration_nodeid()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-get-configuration-nodeid.html) function failed to obtain configuration data. (Bug #43641) * *Cluster API*: The following issues occurred when performing an online (rolling) upgrade of a cluster to a version of MySQL Cluster that supports configuration caching from a version that does not: 1. When using multiple management servers, after upgrading and restarting one *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd, any remaining management servers using the previous version of *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. could not synchronize their configuration data. 2. The MGM API `ndb_mgm_get_configuration_nodeid()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-get-configuration-nodeid.html) function failed to obtain configuration data. (Bug #43641) * If the number of fragments per table rises above a certain threshold, the `DBDIH' kernel block's on-disk table-definition grows large enough to occupy 2 pages. However, in MySQL Cluster NDB 7.0 (including MySQL Cluster NDB 6.4 releases), only 1 page was actually written, causing table definitions stored on disk to be incomplete. This issue was not observed in MySQL Cluster release series prior to MySQL Cluster NDB 7.0. (Bug #44135) * `TransactionDeadlockDetectionTimeout' values less than 100 were treated as 100. This could cause scans to time out unexpectedly. (Bug #44099) * The file `ndberror.c' contained a C++-style comment, which caused builds to fail with some C compilers. (Bug #44036) * A race condition could occur when a data node failed to restart just before being included in the next global checkpoint. This could cause other data nodes to fail. (Bug #43888) * The setting for `ndb_use_transactions' was ignored. This issue was only known to occur in MySQL Cluster NDB 6.4.3 and MySQL Cluster NDB 7.0.4. (Bug #43236) * When a data node process had been killed after allocating a node ID, but before making contact with any other data node processes, it was not possible to restart it due to a node ID allocation failure. This issue could effect either *Note `ndbd': mysql-cluster-programs-ndbd. or *Note `ndbmtd': mysql-cluster-programs-ndbmtd. processes. (Bug #43224) This regression was introduced by Bug #42973. * *Note `ndb_restore': mysql-cluster-programs-ndb-restore. crashed when trying to restore a backup made to a MySQL Cluster running on a platform having different endianness from that on which the original backup was taken. (Bug #39540) * PID files for the data and management node daemons were not removed following a normal shutdown. (Bug #37225) * *Note `ndb_restore `--print_data'': mysql-cluster-programs-ndb-restore. did not handle *Note `DECIMAL': numeric-types. columns correctly. (Bug #37171) * Invoking the management client `START BACKUP' command from the system shell (for example, as *Note `ndb_mgm -e "START BACKUP"': mysql-cluster-programs-ndb-mgm.) did not work correctly, unless the backup ID was included when the command was invoked. Now, the backup ID is no longer required in such cases, and the backup ID that is automatically generated is printed to stdout, similar to how this is done when invoking `START BACKUP' within the management client. (Bug #31754) * When aborting an operation involving both an insert and a delete, the insert and delete were aborted separately. This was because the transaction coordinator did not know that the operations affected on same row, and, in the case of a committed-read (tuple or index) scan, the abort of the insert was performed first, then the row was examined after the insert was aborted but before the delete was aborted. In some cases, this would leave the row in a inconsistent state. This could occur when a local checkpoint was performed during a backup. This issue did not affect primary ley operations or scans that used locks (these are serialized). After this fix, for ordered indexes, all operations that follow the operation to be aborted are now also aborted. * *Disk Data*: When using multi-threaded data nodes, *Note `DROP TABLE': drop-table. statements on Disk Data tables could hang. (Bug #43825) * *Disk Data*: This fix completes one that was made for this issue in MySQL Cluster NDB-7.0.4, which did not rectify the problem in all cases. (Bug #43632) * *Cluster API*: If the largest offset of a `RecordSpecification' used for an `NdbRecord' object was for the `NULL' bits (and thus not a column), this offset was not taken into account when calculating the size used for the `RecordSpecification'. This meant that the space for the `NULL' bits could be overwritten by key or other information. (Bug #43891) * *Cluster API*: *Note `BIT': numeric-types. columns created using the native NDB API format that were not created as nullable could still sometimes be overwritten, or cause other columns to be overwritten. This issue did not effect tables having *Note `BIT': numeric-types. columns created using the mysqld format (always used by MySQL Cluster SQL nodes). (Bug #43802) *Changes in MySQL Cluster NDB 7.0.4 (5.1.32-ndb-7.0.4) * *Functionality added or changed:* * *Important Change*: The default values for a number of MySQL Cluster configuration parameters relating to memory usage and buffering have changed. These parameters include `RedoBuffer', `LongMessageBuffer', `BackupMemory', `BackupDataBufferSize', `BackupLogBufferSize', `BackupWriteSize', `BackupMaxWriteSize', `SendBufferMemory' (when applied to TCP transporters), and `ReceiveBufferMemory'. For more information, see *Note mysql-cluster-configuration::. * When restoring from backup, *Note `ndb_restore': mysql-cluster-programs-ndb-restore. now reports the last global checkpoint reached when the backup was taken. (Bug #37384) *Bugs fixed:* * *Cluster API*: Partition pruning did not work correctly for queries involving multiple range scans. As part of the fix for this issue, several improvements have been made in the NDB API, including the addition of a new `NdbScanOperation::getPruned()' method, a new variant of `NdbIndexScanOperation::setBound()', and a new `PartitionSpec' data structure. (Bug #37934) * *Cluster API*: Partition pruning did not work correctly for queries involving multiple range scans. As part of the fix for this issue, several improvements have been made in the NDB API, including the addition of a new `NdbScanOperation::getPruned()' method, a new variant of `NdbIndexScanOperation::setBound()', and a new `PartitionSpec' data structure. (Bug #37934) * `TimeBetweenLocalCheckpoints' was measured from the end of one local checkpoint to the beginning of the next, rather than from the beginning of one LCP to the beginning of the next. This meant that the time spent performing the LCP was not taken into account when determining the `TimeBetweenLocalCheckpoints' interval, so that LCPs were not started often enough, possibly causing data nodes to run out of redo log space prematurely. (Bug #43567) * The management server failed to start correctly in daemon mode. (Bug #43559) * Following a `DROP NODEGROUP' command, the output of `SHOW' in the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. cliently was not updated to reflect the fact that the data nodes affected by this command were no longer part of a node group. (Bug #43413) * Using indexes containing variable-sized columns could lead to internal errors when the indexes were being built. (Bug #43226) * When using *Note `ndbmtd': mysql-cluster-programs-ndbmtd, multiple data node failures caused the remaining data nodes to fail as well. (Bug #43109) * It was not possible to add new data nodes to the cluster online using multi-threaded data node processes (*Note `ndbmtd': mysql-cluster-programs-ndbmtd.). (Bug #43108) * Some queries using combinations of logical and comparison operators on an indexed column in the `WHERE' clause could fail with the error `Got error 4541 'IndexBound has no bound information' from NDBCLUSTER'. (Bug #42857) * *Disk Data*: When using multi-threaded data nodes, dropping a Disk Data table followed by a data node restart led to a crash. (Bug #43632) * *Disk Data*: When using *Note `ndbmtd': mysql-cluster-programs-ndbmtd, repeated high-volume inserts (on the order of 10000 rows inserted at a time) on a Disk Data table would eventually lead to a data node crash. (Bug #41398) * *Disk Data*: When a log file group had an undo log file whose size was too small, restarting data nodes failed with `Read underflow' errors. As a result of this fix, the minimum permitted `INTIAL_SIZE' for an undo log file is now `1M' (1 megabyte). (Bug #29574) * *Cluster API*: The default `NdbRecord' structures created by `NdbDictionary' could have overlapping null bits and data fields. (Bug #43590) * *Cluster API*: When performing insert or write operations, `NdbRecord' permits key columns to be specified in both the key record and in the attribute record. Only one key column value for each key column should be sent to the NDB kernel, but this was not guaranteed. This is now ensured as follows: For insert and write operations, key column values are taken from the key record; for scan takeover update operations, key column values are taken from the attribute record. (Bug #42238) * *Cluster API*: Ordered index scans using `NdbRecord' formerly expressed a `BoundEQ' range as separate lower and upper bounds, resulting in 2 copies of the column values being sent to the NDB kernel. Now, when a range is specified by `NdbScanOperation::setBound()', the passed pointers, key lengths, and inclusive bits are compared, and only one copy of the equal key columns is sent to the kernel. This makes such operations more efficient, as half the amount of `KeyInfo' is now sent for a `BoundEQ' range as before. (Bug #38793) *Changes in MySQL Cluster NDB 6.4.3 (5.1.32-ndb-6.4.3) * *Functionality added or changed:* * A new data node configuration parameter `MaxLCPStartDelay' has been introduced to facilitate parallel node recovery by causing a local checkpoint to be delayed while recovering nodes are synchronizing data dictionaries and other meta-information. For more information about this parameter, see *Note mysql-cluster-ndbd-definition::. (Bug #43053) * New options are introduced for *Note `ndb_restore': mysql-cluster-programs-ndb-restore. for determining which tables or databases should be restored: * `--include-tables' and `--include-databases' can be used to restore specific tables or databases. * `--exclude-tables' and `--exclude-databases' can be used to exclude the specified tables or databases from being restored. For more information about these options, see *Note mysql-cluster-programs-ndb-restore::. (Bug #40429) * *Disk Data*: It is now possible to specify default locations for Disk Data data files and undo log files, either together or separately, using the data node configuration parameters `FileSystemPathDD', `FileSystemPathDataFiles', and `FileSystemPathUndoFiles'. For information about these configuration parameters, see `Disk Data file system parameters'. It is also now possible to specify a log file group, tablespace, or both, that is created when the cluster is started, using the `InitialLogFileGroup' and `InitialTablespace' data node configuration parameters. For information about these configuration parameters, see `Disk Data object creation parameters'. *Bugs fixed:* * *Performance*: Updates of the `SYSTAB_0' system table to obtain a unique identifier did not use transaction hints for tables having no primary key. In such cases the NDB kernel used a cache size of 1. This meant that each insert into a table not having a primary key required an update of the corresponding `SYSTAB_0' entry, creating a potential performance bottleneck. With this fix, inserts on `NDB' tables without primary keys can be under some conditions be performed up to 100% faster than previously. (Bug #39268) * *Important Note*: It is not possible in this release to install the *Note `InnoDB': innodb-storage-engine. plugin if *Note `InnoDB': innodb-storage-engine. support has been compiled into *Note `mysqld': mysqld. (Bug #42610) This regression was introduced by Bug #29263. * *Packaging*: Packages for MySQL Cluster were missing the `libndbclient.so' and `libndbclient.a' files. (Bug #42278) * *Partitioning*: Executing `ALTER TABLE ... REORGANIZE PARTITION' on an *Note `NDBCLUSTER': mysql-cluster. table having only one partition caused *Note `mysqld': mysqld. to crash. (Bug #41945) See also Bug #40389. * Backup IDs greater than 2^31 were not handled correctly, causing negative values to be used in backup directory names and printouts. (Bug #43042) * When using *Note `ndbmtd': mysql-cluster-programs-ndbmtd, NDB kernel threads could hang while trying to start the data nodes with `LockPagesInMainMemory' set to 1. (Bug #43021) * When using multiple management servers and starting several API nodes (possibly including one or more SQL nodes) whose connectstrings listed the management servers in different order, it was possible for 2 API nodes to be assigned the same node ID. When this happened it was possible for an API node not to get fully connected, consequently producing a number of errors whose cause was not easily recognizable. (Bug #42973) * When using multi-threaded data nodes, `IndexMemory', `MaxNoOfLocalOperations', and `MaxNoOfLocalScans' were effectively multiplied by the number of local query handlers in use by each *Note `ndbmtd': mysql-cluster-programs-ndbmtd. instance. (Bug #42765) See also Bug #42215. * *Note `ndb_error_reporter': mysql-cluster-programs-ndb-error-reporter. worked correctly only with GNU `tar'. (With other versions of `tar', it produced empty archives.) (Bug #42753) * Triggers on *Note `NDBCLUSTER': mysql-cluster. tables caused such tables to become locked. (Bug #42751) See also Bug #16229, Bug #18135. * When performing more than 32 index or tuple scans on a single fragment, the scans could be left hanging. This caused unnecessary timeouts, and in addition could possibly lead to a hang of an LCP. (Bug #42559) * A data node failure that occurred between calls to `NdbIndexScanOperation::readTuples(SF_OrderBy)' and `NdbTransaction::execute()' was not correctly handled; a subsequent call to `nextResult()' caused a null pointer to be deferenced, leading to a segfault in *Note `mysqld': mysqld. (Bug #42545) * If the cluster configuration cache file was larger than 32K, the management server would not start. (Bug #42543) * Issuing `SHOW GLOBAL STATUS LIKE 'NDB%'' before *Note `mysqld': mysqld. had connected to the cluster caused a segmentation fault. (Bug #42458) * When using *Note `ndbmtd': mysql-cluster-programs-ndbmtd. for all data nodes, repeated failures of one data node during DML operations caused other data nodes to fail. (Bug #42450) * Data node failures that occurred before all data nodes had connected to the cluster were not handled correctly, leading to additional data node failures. (Bug #42422) * When using multi-threaded data nodes, their `DataMemory' and `IndexMemory' usage as reported was multiplied by the number of local query handlers (worker threads), making it appear that much more memory was being used than was actually the case. (Bug #42215) See also Bug #42765. * Given a MySQL Cluster containing no data (that is, whose data nodes had all been started using `--initial', and into which no data had yet been imported) and having an empty backup directory, executing `START BACKUP' with a user-specified backup ID caused the data nodes to crash. (Bug #41031) * In some cases, *Note `NDB': mysql-cluster. did not check correctly whether tables had changed before trying to use the query cache. This could result in a crash of the debug MySQL server. (Bug #40464) * *Disk Data*: It was not possible to add an in-memory column online to a table that used a table-level or column-level `STORAGE DISK' option. The same issue prevented `ALTER ONLINE TABLE ... REORGANIZE PARTITION' from working on Disk Data tables. (Bug #42549) * *Disk Data*: Repeated insert and delete operations on disk-based tables could lead to failures in the NDB Tablespace Manager (`TSMAN' kernel block). (Bug #40344) * *Disk Data*: Creating a Disk Data tablespace with a very large extent size caused the data nodes to fail. The issue was observed when using extent sizes of 100 MB and larger. (Bug #39096) * *Disk Data*: Trying to execute a *Note `CREATE LOGFILE GROUP': create-logfile-group. statement using a value greater than `150M' for `UNDO_BUFFER_SIZE' caused data nodes to crash. As a result of this fix, the upper limit for `UNDO_BUFFER_SIZE' is now `600M'; attempting to set a higher value now fails gracefully with an error. (Bug #34102) See also Bug #36702. * *Disk Data*: When attempting to create a tablespace that already existed, the error message returned was `Table or index with given name already exists'. (Bug #32662) * *Disk Data*: Using a path or filename longer than 128 characters for Disk Data undo log files and tablespace data files caused a number of issues, including failures of *Note `CREATE LOGFILE GROUP': create-logfile-group, *Note `ALTER LOGFILE GROUP': alter-logfile-group, *Note `CREATE TABLESPACE': create-tablespace, and *Note `ALTER TABLESPACE': alter-tablespace. statements, as well as crashes of management nodes and data nodes. With this fix, the maximum length for path and file names used for Disk Data undo log files and tablespace data files is now the same as the maximum for the operating system. (Bug #31769, Bug #31770, Bug #31772) * *Disk Data*: Attempting to perform a system restart of the cluster where there existed a logfile group without and undo log files caused the data nodes to crash. *Note*: While issuing a *Note `CREATE LOGFILE GROUP': create-logfile-group. statement without an `ADD UNDOFILE' option fails with an error in the MySQL server, this situation could arise if an SQL node failed during the execution of a valid *Note `CREATE LOGFILE GROUP': create-logfile-group. statement; it is also possible to create a logfile group without any undo log files using the NDB API. (Bug #17614) * *Cluster API*: Some error messages from *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. contained newline (`\n') characters. This could break the MGM API protocol, which uses the newline as a line separator. (Bug #43104) * *Cluster API*: When using an ordered index scan without putting all key columns in the read mask, this invalid use of the NDB API went undetected, which resulted in the use of uninitialized memory. (Bug #42591) *Changes in MySQL Cluster NDB 6.4.2 (5.1.31-ndb-6.4.2) * *Bugs fixed:* * Connections using IPv6 were not handled correctly by *Note `mysqld': mysqld. (Bug #42413) See also Bug #42412, Bug #38247. * When a cluster backup failed with Error 1304 (Node NODE_ID1: Backup request from NODE_ID2 failed to start), no clear reason for the failure was provided. As part of this fix, MySQL Cluster now retries backups in the event of sequence errors. (Bug #42354) See also Bug #22698. * Issuing *Note `SHOW ENGINE NDBCLUSTER STATUS': show-engine. on an SQL node before the management server had connected to the cluster caused *Note `mysqld': mysqld. to crash. (Bug #42264) * When using *Note `ndbmtd': mysql-cluster-programs-ndbmtd, setting `MaxNoOfExecutionThreads' to a value higher than the actual number of cores available and with insufficient `SharedGlobalMemory' caused the data nodes to crash. The fix for this issue changes the behavior of *Note `ndbmtd': mysql-cluster-programs-ndbmtd. such that its internal job buffers no longer rely on `SharedGlobalMemory'. (Bug #42254) *Changes in MySQL Cluster NDB 6.4.1 (5.1.31-ndb-6.4.1) * *Functionality added or changed:* * *Important Change*: Formerly, when the management server failed to create a transporter for a data node connection, `net_write_timeout' seconds elapsed before the data node was actually permitted to disconnect. Now in such cases the disconnection occurs immediately. (Bug #41965) See also Bug #41713. * Formerly, when using MySQL Cluster Replication, records for `empty' epochs--that is, epochs in which no changes to *Note `NDBCLUSTER': mysql-cluster. data or tables took place--were inserted into the `ndb_apply_status' and `ndb_binlog_index' tables on the slave even when `--log-slave-updates' was disabled. Beginning with MySQL Cluster NDB 6.2.16 and MySQL Cluster NDB 6.3.13 this was changed so that these `empty' eopchs were no longer logged. However, it is now possible to re-enable the older behavior (and cause `empty' epochs to be logged) by using the `--ndb-log-empty-epochs' option. For more information, see *Note replication-options-slave::. See also Bug #37472. *Bugs fixed:* * A maximum of 11 `TUP' scans were permitted in parallel. (Bug #42084) * The management server could hang after attempting to halt it with the `STOP' command in the management client. (Bug #42056) See also Bug #40922. * When using *Note `ndbmtd': mysql-cluster-programs-ndbmtd, one thread could flood another thread, which would cause the system to stop with a `job buffer full' condition (currently implemented as an abort). This could be caused by committing or aborting a large transaction (50000 rows or more) on a single data node running *Note `ndbmtd': mysql-cluster-programs-ndbmtd. To prevent this from happening, the number of signals that can be accepted by the system threads is calculated before excuting them, and only executing them if sufficient space is found. (Bug #42052) * MySQL Cluster would not compile when using `libwrap'. This issue was known to occur only in MySQL Cluster NDB 6.4.0. (Bug #41918) * Trying to execute an *Note `ALTER ONLINE TABLE ... ADD COLUMN': alter-table. statement while inserting rows into the table caused *Note `mysqld': mysqld. to crash. (Bug #41905) * When a data node connects to the management server, the node sends its node ID and transporter type; the management server then verifies that there is a transporter set up for that node and that it is in the correct state, and then sends back an acknowledgment to the connecting node. If the transporter was not in the correct state, no reply was sent back to the connecting node, which would then hang until a read timeout occurred (60 seconds). Now, if the transporter is not in the correct state, the management server acknowledges this promptly, and the node immediately disconnects. (Bug #41713) See also Bug #41965. * Issuing `EXIT' in the management client sometimes caused the client to hang. (Bug #40922) * In the event that a MySQL Cluster backup failed due to file permissions issues, conflicting reports were issued in the management client. (Bug #34526) * If all data nodes were shut down, MySQL clients were unable to access *Note `NDBCLUSTER': mysql-cluster. tables and data even after the data nodes were restarted, unless the MySQL clients themselves were restarted. (Bug #33626) *Changes in MySQL Cluster NDB 6.4.0 (5.1.30-ndb-6.4.0) * *Functionality added or changed:* * *Important Change*: MySQL Cluster now caches its configuration data. This means that, by default, the management server only reads the global configuration file (usually named `config.ini') the first time that it is started, and does not automatically re-read the this file when restarted. This behavior can be controlled using new management server options (`--config-dir', `--initial', and `--reload') that have been added for this purpose. For more information, see *Note mysql-cluster-config-file::, and *Note mysql-cluster-programs-ndb-mgmd::. * It is now possible while in Single User Mode to restart all data nodes using `ALL RESTART' in the management client. Restarting of individual nodes while in Single User Mode remains not permitted. (Bug #31056) * It is now possible to add data nodes to a MySQL Cluster online--that is, to a running MySQL Cluster without shutting it down. For information about the procedure for adding data nodes online, see *Note mysql-cluster-online-add-node::. * A multi-threaded version of the MySQL Cluster data node daemon is now available. The multi-threaded *Note `ndbmtd': mysql-cluster-programs-ndbmtd. binary is similar to *Note `ndbd': mysql-cluster-programs-ndbd. and functions in much the same way, but is intended for use on machines with multiple CPU cores. For more information, see *Note mysql-cluster-programs-ndbmtd::. * It is now possible when performing a cluster backup to determine whether the backup matches the state of the data when the backup began or when it ended, using the new `START BACKUP' options `SNAPSHOTSTART' and `SNAPSHOTEND' in the management client. See *Note mysql-cluster-backup-using-management-client::, for more information. * *Cluster API*: Two new `Ndb_cluster_connection' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndb-cluster-connection.html#ndb-ndb-cluster-connection) methods have been added to help in diagnosing problems with NDB API client connections. The `get_latest_error()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndb-cluster-connection-methods.html#ndb-ndb-cluster-connection-get-latest-error) method tells whether or not the latest connection attempt succeeded; if the attempt failed, `get_latest_error_msg()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndb-cluster-connection-methods.html#ndb-ndb-cluster-connection-get-latest-error-msg) provides an error message giving the reason. *Bugs fixed:* * API nodes disconnected too agressively from cluster when data nodes were being restarted. This could sometimes lead to the API node being unable to access the cluster at all during a rolling restart. (Bug #41462) * When long signal buffer exhaustion in the *Note `ndbd': mysql-cluster-programs-ndbd. process resulted in a signal being dropped, the usual handling mechanism did not take fragmented signals into account. This could result in a crash of the data node because the fragmented signal handling mechanism was not able to work with the missing fragments. (Bug #39235) * The failure of a master node during a DDL operation caused the cluster to be unavailable for further DDL operations until it was restarted; failures of nonmaster nodes during DLL operations caused the cluster to become completely inaccessible. (Bug #36718) * Status messages shown in the management client when restarting a management node were inappropriate and misleading. Now, when restarting a management node, the messages displayed are as follows, where NODE_ID is the management node's node ID: ndb_mgm> NODE_ID RESTART Shutting down MGM node NODE_ID for restart Node NODE_ID is being restarted ndb_mgm> (Bug #29275) * A data node failure when `NoOfReplicas' was greater than 2 caused all cluster SQL nodes to crash. (Bug #18621)  File: manual.info, Node: mysql-cluster-news-6-3-series, Next: mysql-cluster-news-6-2-series, Prev: mysql-cluster-news-7-0-series, Up: mysql-cluster-news-series 17.7.7.3 Changes in the MySQL Cluster NDB 6.3 Series .................................................... This section contains unified change history highlights for all MySQL Cluster releases based on version 6.3 of the *Note `NDBCLUSTER': mysql-cluster. storage engine through MySQL Cluster NDB 6.3.45. Included are all changelog entries in the categories _MySQL Cluster_, _Disk Data_, and _Cluster API_. For an overview of features that were added in MySQL Cluster NDB 6.3, see *Note mysql-cluster-development-5-1-ndb-6-3::. * Changes in MySQL Cluster NDB 6.3.45 (5.1.56-ndb-6.3.45) * Changes in MySQL Cluster NDB 6.3.44 (5.1.56-ndb-6.3.44) * Changes in MySQL Cluster NDB 6.3.43 (5.1.56-ndb-6.3.43) * Changes in MySQL Cluster NDB 6.3.42 (5.1.51-ndb-6.3.42) * Changes in MySQL Cluster NDB 6.3.41 (5.1.51-ndb-6.3.41) * Changes in MySQL Cluster NDB 6.3.40 (5.1.51-ndb-6.3.40) * Changes in MySQL Cluster NDB 6.3.39 (5.1.51-ndb-6.3.39) * Changes in MySQL Cluster NDB 6.3.38 (5.1.47-ndb-6.3.38) * Changes in MySQL Cluster NDB 6.3.37 (5.1.47-ndb-6.3.37) * Changes in MySQL Cluster NDB 6.3.36 (5.1.47-ndb-6.3.36) * Changes in MySQL Cluster NDB 6.3.35 (5.1.47-ndb-6.3.35) * Changes in MySQL Cluster NDB 6.3.34 (5.1.44-ndb-6.3.34) * Changes in MySQL Cluster NDB 6.3.33 (5.1.44-ndb-6.3.33) * Changes in MySQL Cluster NDB 6.3.32 (5.1.41-ndb-6.3.32) * Changes in MySQL Cluster NDB 6.3.31a (5.1.41-ndb-6.3.31a) * Changes in MySQL Cluster NDB 6.3.30 (5.1.39-ndb-6.3.30) * Changes in MySQL Cluster NDB 6.3.29 (5.1.39-ndb-6.3.29) * Changes in MySQL Cluster NDB 6.3.28a (5.1.39-ndb-6.3.28a) * Changes in MySQL Cluster NDB 6.3.27 (5.1.37-ndb-6.3.27) * Changes in MySQL Cluster NDB 6.3.26 (5.1.35-ndb-6.3.26) * Changes in MySQL Cluster NDB 6.3.25 (5.1.34-ndb-6.3.25) * Changes in MySQL Cluster NDB 6.3.24 (5.1.32-ndb-6.3.24) * Changes in MySQL Cluster NDB 6.3.23 (5.1.32-ndb-6.3.23) * Changes in MySQL Cluster NDB 6.3.22 (5.1.31-ndb-6.3.22) * Changes in MySQL Cluster NDB 6.3.21 (5.1.31-ndb-6.3.21) * Changes in MySQL Cluster NDB 6.3.20 (5.1.30-ndb-6.3.20) * Changes in MySQL Cluster NDB 6.3.19 (5.1.29-ndb-6.3.19) * Changes in MySQL Cluster NDB 6.3.18 (5.1.28-ndb-6.3.18) * Changes in MySQL Cluster NDB 6.3.17 (5.1.27-ndb-6.3.17) * Changes in MySQL Cluster NDB 6.3.16 (5.1.24-ndb-6.3.16) * Changes in MySQL Cluster NDB 6.3.15 (5.1.24-ndb-6.3.15) * Changes in MySQL Cluster NDB 6.3.14 (5.1.24-ndb-6.3.14) * Changes in MySQL Cluster NDB 6.3.13 (5.1.24-ndb-6.3.13) * Changes in MySQL Cluster NDB 6.3.10 (5.1.23-ndb-6.3.10) * Changes in MySQL Cluster NDB 6.3.9 (5.1.23-ndb-6.3.9) * Changes in MySQL Cluster NDB 6.3.8 (5.1.23-ndb-6.3.8) * Changes in MySQL Cluster NDB 6.3.7 (5.1.23-ndb-6.3.7) * Changes in MySQL Cluster NDB 6.3.6 (5.1.22-ndb-6.3.6) * Changes in MySQL Cluster NDB 6.3.5 (5.1.22-ndb-6.3.5) * Changes in MySQL Cluster NDB 6.3.4 (5.1.22-ndb-6.3.4) * Changes in MySQL Cluster NDB 6.3.3 (5.1.22-ndb-6.3.3) * Changes in MySQL Cluster NDB 6.3.2 (5.1.22-ndb-6.3.2) * Changes in MySQL Cluster NDB 6.3.0 (5.1.19-ndb-6.3.0) *Changes in MySQL Cluster NDB 6.3.45 (5.1.56-ndb-6.3.45) * *Bugs fixed:* * When global checkpoint indexes were written with no intervening end-of-file or megabyte border markers, this could sometimes lead to a situation in which the end of the redo log was mistakenly regarded as being between these GCIs, so that if the restart of a data node took place before the start of the next redo log was overwritten, the node encountered an `Error while reading the REDO log'. (Bug #12653993, Bug #61500) See also Bug #56961. * Error reporting has been improved for cases in which API nodes are unable to connect due to apparent unavailability of node IDs. (Bug #12598398) * Error messages for `Failed to convert connection' transporter registration problems were inspecific. (Bug #12589691) * Under certain rare circumstances, a data node process could fail with Signal 11 during a restart. This was due to uninitialized variables in the `QMGR' kernel block. (Bug #12586190) * Handling of the `MaxNoOfTables' and `MaxNoOfAttributes' configuration parameters was not consistent in all parts of the *Note `NDB': mysql-cluster. kernel, and were only strictly enforced by the `DBDICT' and `SUMA' kernel blocks. This could lead to problems when tables could be created but not replicated. Now these parameters are treated by `SUMA' and `DBDICT' as suggested maximums rather than hard limits, as they are elsewhere in the *Note `NDB': mysql-cluster. kernel. (Bug #61684) * *Cluster API*: Within a transaction, after creating, executing, and closing a scan, calling `NdbTransaction::refresh()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndbtransaction-methods.html#ndb-ndbtransaction-refresh) after creating and executing but not closing a second scan caused the application to crash. (Bug #12646659) *Changes in MySQL Cluster NDB 6.3.44 (5.1.56-ndb-6.3.44) * *Bugs fixed:* * Two unused test files in `storage/ndb/test/sql' contained incorrect versions of the GNU Lesser General Public License. The files and the directory containing them have been removed. (Bug #11810156) See also Bug #11810224. *Changes in MySQL Cluster NDB 6.3.43 (5.1.56-ndb-6.3.43) * *Bugs fixed:* * *Cluster API*: Performing interpreted operations using a unique index did not work correctly, because the interpret bit was kept when sending the lookup to the index table. *Changes in MySQL Cluster NDB 6.3.42 (5.1.51-ndb-6.3.42) * *Bugs fixed:* * A scan with a pushed condition (filter) using the `CommittedRead' lock mode could hang for a short interval when it was aborted when just as it had decided to send a batch. (Bug #11932525) * When aborting a multi-read range scan exactly as it was changing ranges in the local query handler, LQH could fail to detect it, leaving the scan hanging. (Bug #11929643) * *Disk Data*: Limits imposed by the size of `SharedGlobalMemory' were not always enforced consistently with regard to Disk Data undo buffers and log files. This could sometimes cause a *Note `CREATE LOGFILE GROUP': create-logfile-group. or *Note `ALTER LOGFILE GROUP': alter-logfile-group. statement to fail for no apparent reason, or cause the log file group specified by `InitialLogFileGroup' not to be created when starting the cluster. (Bug #57317) *Changes in MySQL Cluster NDB 6.3.41 (5.1.51-ndb-6.3.41) * *Functionality added or changed:* * A new `--rewrite-database' option is added for *Note `ndb_restore': mysql-cluster-programs-ndb-restore, which makes it possible to restore to a database having a different name from that of the database in the backup. For more information, see *Note mysql-cluster-programs-ndb-restore::. (Bug #54327) *Changes in MySQL Cluster NDB 6.3.40 (5.1.51-ndb-6.3.40) * *Functionality added or changed:* * Added the `--skip-broken-objects' option for *Note `ndb_restore': mysql-cluster-programs-ndb-restore. This option causes *Note `ndb_restore': mysql-cluster-programs-ndb-restore. to ignore tables corrupted due to missing blob parts tables, and to continue reading from the backup file and restoring the remaining tables. (Bug #54613) See also Bug #51652. *Bugs fixed:* * Two related problems could occur with read-committed scans made in parallel with transactions combining multiple (concurrent) operations: 1. When committing a multiple-operation transaction that contained concurrent insert and update operations on the same record, the commit arrived first for the insert and then for the update. If a read-committed scan arrived between these operations, it could thus read incorrect data; in addition, if the scan read variable-size data, it could cause the data node to fail. 2. When rolling back a multiple-operation transaction having concurrent delete and insert operations on the same record, the abort arrived first for the delete operation, and then for the insert. If a read-committed scan arrived between the delete and the insert, it could incorrectly assume that the record should not be returned (in other words, the scan treated the insert as though it had not yet been committed). (Bug #59496) * A row insert or update followed by a delete operation on the same row within the same transaction could in some cases lead to a buffer overflow. (Bug #59242) See also Bug #56524. This regression was introduced by Bug #35208. * The `FAIL_REP' signal, used inside the NDB kernel to declare that a node has failed, now includes the node ID of the node that detected the failure. This information can be useful in debugging. (Bug #58904) * In some circumstances, an SQL trigger on an *Note `NDB': mysql-cluster. table could read stale data. (Bug #58538) * During a node takeover, it was possible in some circumstances for one of the remaining nodes to send an extra transaction confirmation (`LQH_TRANSCONF') signal to the `DBTC' kernel block, conceivably leading to a crash of the data node trying to take over as the new transaction coordinator. (Bug #58453) * A query having multiple predicates joined by `OR' in the `WHERE' clause and which used the `sort_union' access method (as shown using *Note `EXPLAIN': explain.) could return duplicate rows. (Bug #58280) * Trying to drop an index while it was being used to perform scan updates caused data nodes to crash. (Bug #58277, Bug #57057) * When handling failures of multiple data nodes, an error in the construction of internal signals could cause the cluster's remaining nodes to crash. This issue was most likely to affect clusters with large numbers of data nodes. (Bug #58240) * Some queries of the form *Note `SELECT ... WHERE COLUMN IN (SUBQUERY)': select. against an *Note `NDB': mysql-cluster. table could cause *Note `mysqld': mysqld. to hang in an endless loop. (Bug #58163) * The number of rows affected by a statement that used a `WHERE' clause having an `IN' condition with a value list containing a great many elements, and that deleted or updated enough rows such that *Note `NDB': mysql-cluster. processed them in batches, was not computed or reported correctly. (Bug #58040) * A query using `BETWEEN' as part of a pushed-down `WHERE' condition could cause mysqld to hang or crash. (Bug #57735) * In some circumstances, it was possible for *Note `mysqld': mysqld. to begin a new multi-range read scan without having closed a previous one. This could lead to exhaustion of all scan operation objects, transaction objects, or lock objects (or some combination of these) in *Note `NDB': mysql-cluster, causing queries to fail with such errors as `Lock wait timeout exceeded' or `Connect failure - out of connection objects'. (Bug #57481) See also Bug #58750. * Queries using `COLUMN IS' [`NOT'] `NULL' on a table with a unique index created with `USING HASH' on COLUMN always returned an empty result. (Bug #57032) * With `engine_condition_pushdown' enabled, a query using `LIKE' on an *Note `ENUM': enum. column of an *Note `NDB': mysql-cluster. table failed to return any results. This issue is resolved by disabling `engine_condition_pushdown' when performing such queries. (Bug #53360) * When a slash character (`/') was used as part of the name of an index on an *Note `NDB': mysql-cluster. table, attempting to execute a *Note `TRUNCATE TABLE': truncate-table. statement on the table failed with the error `Index not found', and the table was rendered unusable. (Bug #38914) * *Disk Data*: In certain cases, a race condition could occur when *Note `DROP LOGFILE GROUP': drop-logfile-group. removed the logfile group while a read or write of one of the effected files was in progress, which in turn could lead to a crash of the data node. (Bug #59502) * *Disk Data*: A race condition could sometimes be created when *Note `DROP TABLESPACE': drop-tablespace. was run concurrently with a local checkpoint; this could in turn lead to a crash of the data node. (Bug #59501) * *Disk Data*: Performing what should have been an online drop of a multi-column index was actually performed offline. (Bug #55618) * *Disk Data*: When at least one data node was not running, queries against the *Note `INFORMATION_SCHEMA.FILES': files-table. table took an excessive length of time to complete because the MySQL server waited for responses from any stopped nodes to time out. Now, in such cases, MySQL does not attempt to contact nodes which are not known to be running. (Bug #54199) * *Cluster API*: Attempting to read the same value (using `getValue()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndboperation-methods.html#ndb-ndboperation-getvalue)) more than 9000 times within the same transaction caused the transaction to hang when executed. Now when more reads are performed in this way than can be accommodated in a single transaction, the call to `execute()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndbtransaction-methods.html#ndb-ndbtransaction-execute) fails with a suitable error. (Bug #58110) *Changes in MySQL Cluster NDB 6.3.39 (5.1.51-ndb-6.3.39) * *Functionality added or changed:* * *Important Change*: The `Id' configuration parameter used with MySQL Cluster management, data, and API nodes (including SQL nodes) is now deprecated, and the `NodeId' parameter (long available as a synonym for `Id' when configuring these types of nodes) should be used instead. `Id' continues to be supported for reasons of backward compatibility, but now generates a warning when used with these types of nodes, and is subject to removal in a future release of MySQL Cluster. This change affects the name of the configuration parameter only, establishing a clear preference for `NodeId' over `Id' in the `[mgmd]', `[ndbd]', `[mysql]', and `[api]' sections of the MySQL Cluster global configuration (`config.ini') file. The behavior of unique identifiers for management, data, and SQL and API nodes in MySQL Cluster has not otherwise been altered. The `Id' parameter as used in the `[computer]' section of the MySQL Cluster global configuration file is not affected by this change. *Bugs fixed:* * *Packaging*: MySQL Cluster RPM distributions did not include a `shared-compat' RPM for the MySQL Server, which meant that MySQL applications depending on `libmysqlclient.so.15' (MySQL 5.0 and earlier) no longer worked. (Bug #38596) * The `LQHKEYREQ' request message used by the local query handler when checking the major schema version of a table, being only 16 bits wide, could cause this check to fail with an `Invalid schema version' error (*Note `NDB': mysql-cluster. error code 1227). This issue occurred after creating and dropping (and re-creating) the same table 65537 times, then trying to insert rows into the table. (Bug #57896) See also Bug #57897. * An internal buffer overrun could cause a data node to fail. (Bug #57767) * Data nodes compiled with `gcc' 4.5 or higher crashed during startup. (Bug #57761) * *Note `ndb_restore': mysql-cluster-programs-ndb-restore. now retries failed transactions when replaying log entries, just as it does when restoring data. (Bug #57618) * During a GCP takeover, it was possible for one of the data nodes not to receive a `SUB_GCP_COMPLETE_REP' signal, with the result that it would report itself as `GCP_COMMITTING' while the other data nodes reported `GCP_PREPARING'. (Bug #57522) * Specifying a *Note `WHERE': select. clause of the form `RANGE1 OR RANGE2' when selecting from an *Note `NDB': mysql-cluster. table having a primary key on multiple columns could result in Error 4259 `Invalid set of range scan bounds' if RANGE2 started exactly where RANGE1 ended and the primary key definition declared the columns in a different order relative to the order in the table's column list. (Such a query should simply return all rows in the table, since any expression `VALUE < CONSTANT OR VALUE >= CONSTANT' is always true.) Example Suppose `t' is an *Note `NDB': mysql-cluster. table defined by the following *Note `CREATE TABLE': create-table. statement: CREATE TABLE t (a, b, PRIMARY KEY (b, a)) ENGINE NDB; This issue could then be triggered by a query such as this one: SELECT * FROM t WHERE b < 8 OR b >= 8; In addition, the order of the ranges in the `WHERE' clause was significant; the issue was not triggered, for example, by the query *Note `SELECT * FROM t WHERE b <= 8 OR b > 8': select. (Bug #57396) * A GCP stop is detected using 2 parameters which determine the maximum time that a global checkpoint or epoch can go unchanged; one of these controls this timeout for GCPs and one controls the timeout for epochs. Suppose the cluster is configured such that `TimeBetweenEpochsTimeout' is 100 ms but `HeartbeatIntervalDbDb' is 1500 ms. A node failure can be signalled after 4 missed heartbeats--in this case, 6000 ms. However, this would exceed `TimeBetweenEpochsTimeout', causing false detection of a GCP. To prevent this from happening, the configured value for `TimeBetweenEpochsTimeout' is automatically adjusted, based on the values of `HeartbeatIntervalDbDb' and `ArbitrationTimeout'. The current issue arose when the automatic adjustment routine did not correctly take into consideration the fact that, during cascading node-failures, several intervals of length `4 * (HeartbeatIntervalDBDB + ArbitrationTimeout)' may elapse before all node failures have internally been resolved. This could cause false GCP detection in the event of a cascading node failure. (Bug #57322) * Queries using `WHERE VARCHAR_PK_COLUMN LIKE 'PATTERN%'' or `WHERE VARCHAR_PK_COLUMN LIKE 'PATTERN_'' against an *Note `NDB': mysql-cluster. table having a *Note `VARCHAR': char. column as its primary key failed to return all matching rows. (Bug #56853) * When a data node angel process failed to fork off a new worker process (to replace one that had failed), the failure was not handled. This meant that the angel process either transformed itself into a worker process, or itself failed. In the first case, the data node continued to run, but there was no longer any angel to restart it in the event of failure, even with `StopOnError' set to 0. (Bug #53456) * *Disk Data*: Adding unique indexes to *Note `NDB': mysql-cluster. Disk Data tables could take an extremely long time. This was particularly noticeable when using *Note `ndb_restore `--rebuild-indexes'': mysql-cluster-programs-ndb-restore. (Bug #57827) * *Cluster API*: An application dropping a table at the same time that another application tried to set up a replication event on the same table could lead to a crash of the data node. The same issue could sometimes cause `NdbEventOperation::execute()' to hang. (Bug #57886) * *Cluster API*: An NDB API client program under load could abort with an assertion error in `TransporterFacade::remove_from_cond_wait_queue'. (Bug #51775) See also Bug #32708. *Changes in MySQL Cluster NDB 6.3.38 (5.1.47-ndb-6.3.38) * *Functionality added or changed:* * *Note `mysqldump': mysqldump. as supplied with MySQL Cluster now has an `--add-drop-trigger' option which adds a *Note `DROP TRIGGER IF EXISTS': drop-trigger. statement before each dumped trigger definition. (Bug #55691) See also Bug #34325, Bug #11747863. * *Cluster API*: The MGM API function `ndb_mgm_get_version()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-get-version.html), which was previously internal, has now been moved to the public API. This function can be used to get `NDB' storage engine and other version information from the management server. (Bug #51310) See also Bug #51273. *Bugs fixed:* * A data node can be shut down having completed and synchronized a given GCI X, while having written a great many log records belonging to the next GCI X + 1, as part of normal operations. However, when starting, completing, and synchronizing GCI X + 1, then the log records from original start must not be read. To make sure that this does not happen, the REDO log reader finds the last GCI to restore, scans forward from that point, and erases any log records that were not (and should never be) used. The current issue occurred because this scan stopped immediately as soon as it encountered an empty page. This was problematic because the REDO log is divided into several files; thus, it could be that there were log records in the beginning of the next file, even if the end of the previous file was empty. These log records were never invalidated; following a start or restart, they could be reused, leading to a corrupt REDO log. (Bug #56961) * An error in program flow in `ndbd.cpp' could result in data node shutdown routines being called multiple times. (Bug #56890) * When distributing *Note `CREATE TABLE': create-table. and *Note `DROP TABLE': drop-table. operations among several SQL nodes attached to a MySQL Cluster. the `LOCK_OPEN' lock normally protecting *Note `mysqld': mysqld.'s internal table list is released so that other queries or DML statements are not blocked. However, to make sure that other DDL is not executed simultaneously, a global schema lock (implemented as a row-level lock by `NDB') is used, such that all operations that can modify the state of the *Note `mysqld': mysqld. internal table list also need to acquire this global schema lock. The *Note `SHOW TABLE STATUS': show-table-status. statement did not acquire this lock. (Bug #56841) * In certain cases, *Note `DROP DATABASE': drop-database. could sometimes leave behind a cached table object, which caused problems with subsequent DDL operations. (Bug #56840) * Memory pages used for `DataMemory', once assigned to ordered indexes, were not ever freed, even after any rows that belonged to the corresponding indexes had been deleted. (Bug #56829) * MySQL Cluster stores, for each row in each `NDB' table, a Global Checkpoint Index (GCI) which identifies the last committed transaction that modified the row. As such, a GCI can be thought of as a coarse-grained row version. Due to changes in the format used by `NDB' to store local checkpoints (LCPs) in MySQL Cluster NDB 6.3.11, it could happen that, following cluster shutdown and subsequent recovery, the GCI values for some rows could be changed unnecessarily; this could possibly, over the course of many node or system restarts (or both), lead to an inconsistent database. (Bug #56770) * When multiple SQL nodes were connected to the cluster and one of them stopped in the middle of a DDL operation, the *Note `mysqld': mysqld. process issuing the DDL timed out with the error `distributing TBL_NAME timed out. Ignoring'. (Bug #56763) * An online *Note `ALTER TABLE ... ADD COLUMN': alter-table. operation that changed the table schema such that the number of 32-bit words used for the bitmask allocated to each DML operation increased during a transaction in DML which was performed prior to DDL which was followed by either another DML operation or--if using replication--a commit, led to data node failure. This was because the data node did not take into account that the bitmask for the before-image was smaller than the current bitmask, which caused the node to crash. (Bug #56524) * The text file `cluster_change_hist.txt' containing old MySQL Cluster changelog information was no longer being maintained, and so has been removed from the tree. (Bug #56116) * The failure of a data node during some scans could cause other data nodes to fail. (Bug #54945) * Exhausting the number of available commit-ack markers (controlled by the `MaxNoOfConcurrentTransactions' parameter) led to a data node crash. (Bug #54944) * When running a *Note `SELECT': select. on an *Note `NDB': mysql-cluster. table with *Note `BLOB': blob. or *Note `TEXT': blob. columns, memory was allocated for the columns but was not freed until the end of the *Note `SELECT': select. This could cause problems with excessive memory usage when dumping (using for example *Note `mysqldump': mysqldump.) tables with such columns and having many rows, large column values, or both. (Bug #52313) See also Bug #56488, Bug #50310. *Changes in MySQL Cluster NDB 6.3.37 (5.1.47-ndb-6.3.37) * *Functionality added or changed:* * *Important Change*: More finely-grained control over restart-on-failure behavior is provided with two new data node configuration parameters `MaxStartFailRetries' and `StartFailRetryDelay'. `MaxStartFailRetries' limits the total number of retries made before giving up on starting the data node; `StartFailRetryDelay' sets the number of seconds between retry attempts. These parameters are used only if `StopOnError' is set to 0. For more information, see *Note mysql-cluster-ndbd-definition::. (Bug #54341) *Bugs fixed:* * Following a failure of the master data node, the new master sometimes experienced a race condition which caused the node to terminate with a GcpStop error. (Bug #56044) * The warning `MaxNoOfExecutionThreads (#) > LockExecuteThreadToCPU count (#), this could cause contention' could be logged when running *Note `ndbd': mysql-cluster-programs-ndbd, even though the condition described can occur only when using *Note `ndbmtd': mysql-cluster-programs-ndbmtd. (Bug #54342) * The graceful shutdown of a data node could sometimes cause transactions to be aborted unnecessarily. (Bug #18538) See also Bug #55641. *Changes in MySQL Cluster NDB 6.3.36 (5.1.47-ndb-6.3.36) * *Functionality added or changed:* * Added the `DictTrace' data node configuration parameter, for use in debugging *Note `NDB': mysql-cluster. code. For more information, see *Note mysql-cluster-ndbd-definition::. (Bug #55963) *Bugs fixed:* * *Cluster API*: *Important Change*: The poll and select calls made by the MGM API were not interrupt-safe; that is, a signal caught by the process while waiting for an event on one or more sockets returned error -1 with `errno' set to EINTR. This caused problems with MGM API functions such as `ndb_logevent_get_next()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-logevent-get-next.html) and `ndb_mgm_get_status2()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-get-status2.html). To fix this problem, the internal `ndb_socket_poller::poll()' function has been made EINTR-safe. The old version of this function has been retained as `poll_unsafe()', for use by those parts of NDB that do not need the EINTR-safe version of the function. (Bug #55906) * When another data node failed, a given data node `DBTC' kernel block could time out while waiting for `DBDIH' to signal commits of pending transactions, leading to a crash. Now in such cases the timeout generates a prinout, and the data node continues to operate. (Bug #55715) * The `configure.js' option `WITHOUT_DYNAMIC_PLUGINS=TRUE' was ignored when building MySQL Cluster for Windows using `CMake'. Among the effects of this issue was that `CMake' attempted to build the `InnoDB' storage engine as a plugin (`.DLL' file) even though the `InnoDB Plugin' is not currently supported by MySQL Cluster. (Bug #54913) * It was possible for a *Note `DROP DATABASE': drop-database. statement to remove *Note `NDB': mysql-cluster. hidden blob tables without removing the parent tables, with the result that the tables, although hidden to MySQL clients, were still visible in the output of *Note `ndb_show_tables': mysql-cluster-programs-ndb-show-tables. but could not be dropped using *Note `ndb_drop_table': mysql-cluster-programs-ndb-drop-table. (Bug #54788) * An excessive number of timeout warnings (normally used only for debugging) were written to the data node logs. (Bug #53987) * *Disk Data*: As an optimization when inserting a row to an empty page, the page is not read, but rather simply initialized. However, this optimzation was performed in all cases when an empty row was inserted, even though it should have been done only if it was the first time that the page had been used by a table or fragment. This is because, if the page had been in use, and then all records had been released from it, the page still needed to be read to learn its log sequence number (LSN). This caused problems only if the page had been flushed using an incorrect LSN and the data node failed before any local checkpoint was completed--which would removed any need to apply the undo log, hence the incorrect LSN was ignored. The user-visible result of the incorrect LSN was that it caused the data node to fail during a restart. It was perhaps also possible (although not conclusively proven) that this issue could lead to incorrect data. (Bug #54986) * *Cluster API*: Calling `NdbTransaction::refresh()' did not update the timer for `TransactionInactiveTimeout'. (Bug #54724) *Changes in MySQL Cluster NDB 6.3.35 (5.1.47-ndb-6.3.35) * *Functionality added or changed:* * Restrictions on some types of mismatches in column definitions when restoring data using *Note `ndb_restore': mysql-cluster-programs-ndb-restore. have been relaxed. These include the following types of mismatches: * Different `COLUMN_FORMAT' settings (`FIXED', `DYNAMIC', `DEFAULT') * Different `STORAGE' settings (`MEMORY', `DISK') * Different default values * Different distribution key settings Now, when one of these types of mismatches in column definitions is encountered, *Note `ndb_restore': mysql-cluster-programs-ndb-restore. no longer stops with an error; instead, it accepts the data and inserts it into the target table, while issuing a warning to the user. For more information, see *Note mysql-cluster-programs-ndb-restore::. (Bug #54423) See also Bug #53810, Bug #54178, Bug #54242, Bug #54279. * Introduced the `HeartbeatOrder' data node configuration parameter, which can be used to set the order in which heartbeats are transmitted between data nodes. This parameter can be useful in situations where multiple data nodes are running on the same host and a temporary disruption in connectivity between hosts would otherwise cause the loss of a node group, leading to failure of the cluster. (Bug #52182) *Bugs fixed:* * The disconnection of all API nodes (including SQL nodes) during an *Note `ALTER TABLE': alter-table. caused a memory leak. (Bug #54685) * If a node shutdown (either in isolation or as part of a system shutdown) occurred directly following a local checkpoint, it was possible that this local checkpoint would not be used when restoring the cluster. (Bug #54611) * When performing an online alter table where 2 or more SQL nodes connected to the cluster were generating binary logs, an incorrect message could be sent from the data nodes, causing *Note `mysqld': mysqld. processes to crash. This problem was often difficult to detect, because restarting SQL node or data node processes could clear the error, and because the crash in *Note `mysqld': mysqld. did not occur until several minutes after the erroneous message was sent and received. (Bug #54168) * A table having the maximum number of attributes permitted could not be backed up using the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client. *Note*: The maximum number of attributes supported per table is not the same for all MySQL Cluster releases. See *Note mysql-cluster-limitations-database-objects::, to determine the maximum that applies in the release which you are using. (Bug #54155) * During initial node restarts, initialization of the REDO log was always performed 1 node at a time, during start phase 4. Now this is done during start phase 2, so that the initialization can be performed in parallel, thus decreasing the time required for initial restarts involving multiple nodes. (Bug #50062) * *Cluster API*: When using the NDB API, it was possible to rename a table with the same name as that of an existing table. *Note*: This issue did not affect table renames executed using SQL on MySQL servers acting as MySQL Cluster API nodes. (Bug #54651) * *Cluster API*: An excessive number of client connections, such that more than 1024 file descriptors, sockets, or both were open, caused NDB API applications to crash. (Bug #34303) *Changes in MySQL Cluster NDB 6.3.34 (5.1.44-ndb-6.3.34) * *Functionality added or changed:* * A `--wait-nodes' option has been added for *Note `ndb_waiter': mysql-cluster-programs-ndb-waiter. When this option is used, the program waits only for the nodes having the listed IDs to reach the desired state. For more information, see *Note mysql-cluster-programs-ndb-waiter::. (Bug #52323) * Added the `--skip-unknown-objects' option for *Note `ndb_restore': mysql-cluster-programs-ndb-restore. This option causes *Note `ndb_restore': mysql-cluster-programs-ndb-restore. to ignore any schema objects which it does not recognize. Currently, this is useful chiefly for restoring native backups made from a cluster running MySQL Cluster NDB 7.0 to a cluster running MySQL Cluster NDB 6.3. *Bugs fixed:* * *Cluster API*: *Incompatible Change*: The default behavior of the NDB API Event API has changed as follows: Previously, when creating an `Event', DDL operations (alter and drop operations on tables) were automatically reported on any event operation that used this event, but as a result of this change, this is no longer the case. Instead, you must now invoke the event's `setReport()' method, with the new `EventReport' value `ER_DDL', to get this behavior. For existing NDB API applications where you wish to retain the old behavior, you must update the code as indicated previously, then recompile, following an upgrade. Otherwise, DDL operations are no longer reported after upgrading `libndbnclient'. For more information, see The `Event::EventReport' Type (http://dev.mysql.com/doc/ndbapi/en/ndb-event-types.html#ndb-event-eventreport), and `Event::setReport()' (http://dev.mysql.com/doc/ndbapi/en/ndb-event-methods.html#ndb-event-setreport). (Bug #53308) * *Cluster API*: *Incompatible Change*: The default behavior of the NDB API Event API has changed as follows: Previously, when creating an `Event', DDL operations (alter and drop operations on tables) were automatically reported on any event operation that used this event, but as a result of this change, this is no longer the case. Instead, you must now invoke the event's `setReport()' method, with the new `EventReport' value `ER_DDL', to get this behavior. For existing NDB API applications where you wish to retain the old behavior, you must update the code as indicated previously, then recompile, following an upgrade. Otherwise, DDL operations are no longer reported after upgrading `libndbnclient'. For more information, see The `Event::EventReport' Type (http://dev.mysql.com/doc/ndbapi/en/ndb-event-types.html#ndb-event-eventreport), and `Event::setReport()' (http://dev.mysql.com/doc/ndbapi/en/ndb-event-methods.html#ndb-event-setreport). (Bug #53308) * Creating a Disk Data table, dropping it, then creating an in-memory table and performing a restart, could cause data node processes to fail with errors in the `DBTUP' kernel block if the new table's internal ID was the same as that of the old Disk Data table. This could occur because undo log handling during the restart did not check that the table having this ID was now in-memory only. (Bug #53935) * A table created while `ndb_table_no_logging' was enabled was not always stored to disk, which could lead to a data node crash with `Error opening DIH schema files for table'. (Bug #53934) * An internal buffer allocator used by *Note `NDB': mysql-cluster. has the form `alloc(WANTED, MINIMUM)' and attempts to allocate WANTED pages, but is permitted to allocate a smaller number of pages, between WANTED and MINIMUM. However, this allocator could sometimes allocate fewer than MINIMUM pages, causing problems with multi-threaded building of ordered indexes. (Bug #53580) * When compiled with support for `epoll' but this functionality is not available at runtime, MySQL Cluster tries to fall back to use the `select()' function in its place. However, an extra `ndbout_c()' call in the transporter registry code caused *Note `ndbd': mysql-cluster-programs-ndbd. to fail instead. (Bug #53482) * `NDB' truncated a column declared as *Note `DECIMAL(65,0)': numeric-types. to a length of 64. Now such a column is accepted and handled correctly. In cases where the maximum length (65) is exceeded, `NDB' now raises an error instead of truncating. (Bug #53352) * When a watchdog shutdown occurred due to an error, the process was not terminated quickly enough, sometimes resulting in a hang. (To correct this, the internal `_exit()' function is now called in such situations, rather than `exit()'.) (Bug #53246) * Setting `DataMemory' higher than 4G on 32-bit platforms caused *Note `ndbd': mysql-cluster-programs-ndbd. to crash, instead of failing gracefully with an error. (Bug #52536, Bug #50928) * NDB did not distinguish correctly between table names differing only by lettercase when `lower_case_table_names' was set to 0. (Bug #33158) * `ndb_mgm -e "ALL STATUS"' erroneously reported that data nodes remained in start phase 0 until they had actually started. *Changes in MySQL Cluster NDB 6.3.33 (5.1.44-ndb-6.3.33) * *Functionality added or changed:* * *Cluster API*: It is now possible to determine, using the *Note `ndb_desc': mysql-cluster-programs-ndb-desc. utility or the NDB API, which data nodes contain replicas of which partitions. For *Note `ndb_desc': mysql-cluster-programs-ndb-desc, a new `--extra-node-info' option is added to cause this information to be included in its output. A new method `Table::getFragmentNodes()' is added to the NDB API for obtaining this information programmatically. (Bug #51184) * *Cluster API*: It is now possible to determine, using the *Note `ndb_desc': mysql-cluster-programs-ndb-desc. utility or the NDB API, which data nodes contain replicas of which partitions. For *Note `ndb_desc': mysql-cluster-programs-ndb-desc, a new `--extra-node-info' option is added to cause this information to be included in its output. A new method `Table::getFragmentNodes()' is added to the NDB API for obtaining this information programmatically. (Bug #51184) * Formerly, the `REPORT' and `DUMP' commands returned output to all *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. clients connected to the same MySQL Cluster. Now, these commands return their output only to the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client that actually issued the command. (Bug #40865) *Bugs fixed:* * If a node or cluster failure occurred while *Note `mysqld': mysqld. was scanning the `ndb.ndb_schema' table (which it does when attempting to connect to the cluster), insufficient error handling could lead to a crash by *Note `mysqld': mysqld. in certain cases. This could happen in a MySQL Cluster with a great many tables, when trying to restart data nodes while one or more *Note `mysqld': mysqld. processes were restarting. (Bug #52325) * After running a mixed series of node and system restarts, a system restart could hang or fail altogether. This was caused by setting the value of the newest completed global checkpoint too low for a data node performing a node restart, which led to the node reporting incorrect GCI intervals for its first local checkpoint. (Bug #52217) * When performing a complex mix of node restarts and system restarts, the node that was elected as master sometimes required optimized node recovery due to missing `REDO' information. When this happened, the node crashed with `Failure to recreate object ... during restart, error 721' (because the `DBDICT' restart code was run twice). Now when this occurs, node takeover is executed immediately, rather than being made to wait until the remaining data nodes have started. (Bug #52135) See also Bug #48436. * The redo log protects itself from being filled up by periodically checking how much space remains free. If insufficient redo log space is available, it sets the state `TAIL_PROBLEM' which results in transactions being aborted with error code 410 (`out of redo log'). However, this state was not set following a node restart, which meant that if a data node had insufficient redo log space following a node restart, it could crash a short time later with `Fatal error due to end of REDO log'. Now, this space is checked during node restarts. (Bug #51723) * The output of the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client `REPORT BACKUPSTATUS' command could sometimes contain errors due to uninitialized data. (Bug #51316) * A `GROUP BY' query against *Note `NDB': mysql-cluster. tables sometimes did not use any indexes unless the query included a `FORCE INDEX' option. With this fix, indexes are used by such queries (where otherwise possible) even when `FORCE INDEX' is not specified. (Bug #50736) * The *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client sometimes inserted extra prompts within the output of the `REPORT MEMORYUSAGE' command. (Bug #50196) * Issuing a command in the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client after it had lost its connection to the management server could cause the client to crash. (Bug #49219) * The *Note `ndb_print_backup_file': mysql-cluster-programs-ndb-print-backup-file. utility failed to function, due to a previous internal change in the NDB code. (Bug #41512, Bug #48673) * When the `MemReportFrequency' configuration parameter was set in `config.ini', the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client `REPORT MEMORYUSAGE' command printed its output multiple times. (Bug #37632) * *Note `ndb_mgm -e "... REPORT ..."': mysql-cluster-programs-ndb-mgm. did not write any output to `stdout'. The fix for this issue also prevents the cluster log from being flooded with `INFO' messages when `DataMemory' usage reaches 100%, and insures that when the usage is decreased, an appropriate message is written to the cluster log. (Bug #31542, Bug #44183, Bug #49782) * *Disk Data*: Inserts of blob column values into a MySQL Cluster Disk Data table that exhausted the tablespace resulted in misleading `no such tuple' error messages rather than the expected error `tablespace full'. This issue appeared similar to Bug#48113, but had a different underlying cause. (Bug #52201) * *Disk Data*: The error message returned after atttempting to execute *Note `ALTER LOGFILE GROUP': alter-logfile-group. on an nonexistent logfile group did not indicate the reason for the failure. (Bug #51111) * *Cluster API*: When reading blob data with lock mode `LM_SimpleRead', the lock was not upgraded as expected. (Bug #51034) * *Cluster API*: A number of issues were corrected in the NDB API coding examples found in the `storage/ndb/ndbapi-examples' directory in the MySQL Cluster source tree. These included possible endless recursion in `ndbapi_scan.cpp' as well as problems running some of the examples on systems using Windows or Mac OS X due to the lettercase used for some table names. (Bug #30552, Bug #30737) *Changes in MySQL Cluster NDB 6.3.32 (5.1.41-ndb-6.3.32) * *Functionality added or changed:* * A new configuration parameter `HeartbeatThreadPriority' makes it possible to select between a first-in, first-out or round-round scheduling policy for management node and API node heartbeat threads, as well as to set the priority of these threads. See *Note mysql-cluster-mgm-definition::, or *Note mysql-cluster-api-definition::, for more information. (Bug #49617) * *Disk Data*: The *Note `ndb_desc': mysql-cluster-programs-ndb-desc. utility can now show the extent space and free extent space for subordinate *Note `BLOB': blob. and *Note `TEXT': blob. columns (stored in hidden `BLOB' tables by NDB). A `--blob-info' option has been added for this program that causes *Note `ndb_desc': mysql-cluster-programs-ndb-desc. to generate a report for each subordinate `BLOB' table. For more information, see *Note mysql-cluster-programs-ndb-desc::. (Bug #50599) *Bugs fixed:* * When one or more data nodes read their LCPs and applied undo logs significantly faster than others, this could lead to a race condition causing system restarts of data nodes to hang. This could most often occur when using both *Note `ndbd': mysql-cluster-programs-ndbd. and *Note `ndbmtd': mysql-cluster-programs-ndbmtd. processes for the data nodes. (Bug #51644) * When deciding how to divide the REDO log, the `DBDIH' kernel block saved more than was needed to restore the previous local checkpoint, which could cause REDO log space to be exhausted prematurely (`NDB' error 410). (Bug #51547) * DML operations can fail with `NDB' error 1220 (`REDO log files overloaded...') if the opening and closing of REDO log files takes too much time. If this occurred as a GCI marker was being written in the REDO log while REDO log file 0 was being opened or closed, the error could persist until a GCP stop was encountered. This issue could be triggered when there was insufficient REDO log space (for example, with configuration parameter settings `NoOfFragmentLogFiles = 6' and `FragmentLogFileSize = 6M') with a load including a very high number of updates. (Bug #51512) See also Bug #20904. * During an online upgrade from MySQL Cluster NDB 6.2 to MySQL Cluster NDB 6.3, a sufficiently large amount of traffic with more than 1 DML operation per transaction could lead.an NDB 6.3 data node to crash an NDB 6.2 data node with an internal error in the `DBLOQH' kernel block. (Bug #51389) * A side effect of the *Note `ndb_restore': mysql-cluster-programs-ndb-restore. `--disable-indexes' and `--rebuild-indexes' options is to change the schema versions of indexes. When a *Note `mysqld': mysqld. later tried to drop a table that had been restored from backup using one or both of these options, the server failed to detect these changed indexes. This caused the table to be dropped, but the indexes to be left behind, leading to problems with subsequent backup and restore operations. (Bug #51374) * *Note `ndb_restore': mysql-cluster-programs-ndb-restore. crashed while trying to restore a corrupted backup, due to missing error handling. (Bug #51223) * The *Note `ndb_restore': mysql-cluster-programs-ndb-restore. message `Successfully created index `PRIMARY`...' was directed to `stderr' instead of `stdout'. (Bug #51037) * When using `NoOfReplicas' equal to 1 or 2, if data nodes from one node group were restarted 256 times and applications were running traffic such that it would encounter *Note `NDB': mysql-cluster. error 1204 (`Temporary failure, distribution changed'), the live node in the node group would crash, causing the cluster to crash as well. The crash occurred only when the error was encountered on the 256th restart; having the error on any previous or subsequent restart did not cause any problems. (Bug #50930) * A *Note `SELECT': select. requiring a sort could fail with the error `Can't find record in 'TABLE'' when run concurrently with a *Note `DELETE': delete. from the same table. (Bug #45687) * *Cluster API*: An issue internal to *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. could cause problems when trying to start a large number of data nodes at the same time. (Bug #51273) See also Bug #51310. *Changes in MySQL Cluster NDB 6.3.31a (5.1.41-ndb-6.3.31a) * *Bugs fixed:* * An initial restart of a data node configured with a large amount of memory could fail with a `Pointer too large' error. (Bug #51027) This regression was introduced by Bug #47818. *Changes in MySQL Cluster NDB 6.3.30 (5.1.39-ndb-6.3.30) * *Functionality added or changed:* * Added multi-threaded ordered index building capability during system restarts or node restarts, controlled by the `BuildIndexThreads' data node configuration parameter (also introduced in this release). *Changes in MySQL Cluster NDB 6.3.29 (5.1.39-ndb-6.3.29) * *Functionality added or changed:* * This enhanced functionality is supported for upgrades to MySQL Cluster NDB 7.0 when the *Note `NDB': mysql-cluster. engine version is 7.0.10 or later. (Bug #48528, Bug #49163) * The output from *Note `ndb_config': mysql-cluster-programs-ndb-config. `--configinfo' `--xml' now indicates, for each configuration parameter, the following restart type information: * Whether a system restart or a node restart is required when resetting that parameter; * Whether cluster nodes need to be restarted using the `--initial' option when resetting the parameter. (Bug #47366) *Bugs fixed:* * Node takeover during a system restart occurs when the REDO log for one or more data nodes is out of date, so that a node restart is invoked for that node or those nodes. If this happens while a *Note `mysqld': mysqld. process is attached to the cluster as an SQL node, the *Note `mysqld': mysqld. takes a global schema lock (a row lock), while trying to set up cluster-internal replication. However, this setup process could fail, causing the global schema lock to be held for an excessive length of time, which made the node restart hang as well. As a result, the mysqld failed to set up cluster-internal replication, which led to tables being read only, and caused one node to hang during the restart. *Note*: This issue could actually occur in MySQL Cluster NDB 7.0 only, but the fix was also applied MySQL Cluster NDB 6.3, in order to keep the two codebases in alignment. (Bug #49560) * Sending `SIGHUP' to a *Note `mysqld': mysqld. running with the `--ndbcluster' and `--log-bin' options caused the process to crash instead of refreshing its log files. (Bug #49515) * If the master data node receiving a request from a newly-started API or data node for a node ID died before the request has been handled, the management server waited (and kept a mutex) until all handling of this node failure was complete before responding to any other connections, instead of responding to other connections as soon as it was informed of the node failure (that is, it waited until it had received a NF_COMPLETEREP signal rather than a NODE_FAILREP signal). On visible effect of this misbehavior was that it caused management client commands such as SHOW and ALL STATUS to respond with unnecessary slowness in such circumstances. (Bug #49207) * When evaluating the options `--include-databases', `--include-tables', `--exclude-databases', and `--exclude-tables', the *Note `ndb_restore': mysql-cluster-programs-ndb-restore. program overwrote the result of the database-level options with the result of the table-level options rather than merging these results together, sometimes leading to unexpected and unpredictable results. As part of the fix for this problem, the semantics of these options have been clarified; because of this, the rules governing their evaluation have changed slightly. These changes be summed up as follows: * All `--include-*' and `--exclude-*' options are now evaluated from right to left in the order in which they are passed to *Note `ndb_restore': mysql-cluster-programs-ndb-restore. * All `--include-*' and `--exclude-*' options are now cumulative. * In the event of a conflict, the first (rightmost) option takes precedence. For more detailed information and examples, see *Note mysql-cluster-programs-ndb-restore::. (Bug #48907) * When performing tasks that generated large amounts of I/O (such as when using *Note `ndb_restore': mysql-cluster-programs-ndb-restore.), an internal memory buffer could overflow, causing data nodes to fail with signal 6. Subsequent analysis showed that this buffer was not actually required, so this fix removes it. (Bug #48861) * Exhaustion of send buffer memory or long signal memory caused data nodes to crash. Now an appropriate error message is provided instead when this situation occurs. (Bug #48852) * Under certain conditions, accounting of the number of free scan records in the local query handler could be incorrect, so that during node recovery or a local checkpoint operations, the LQH could find itself lacking a scan record that is expected to find, causing the node to crash. (Bug #48697) See also Bug #48564. * The creation of an ordered index on a table undergoing DDL operations could cause a data node crash under certain timing-dependent conditions. (Bug #48604) * During an LCP master takeover, when the newly elected master did not receive a `COPY_GCI' LCP protocol message but other nodes participating in the local checkpoint had received one, the new master could use an uninitialized variable, which caused it to crash. (Bug #48584) * When running many parallel scans, a local checkpoint (which performs a scan internally) could find itself not getting a scan record, which led to a data node crash. Now an extra scan record is reserved for this purpose, and a problem with obtaining the scan record returns an appropriate error (error code 489, `Too many active scans'). (Bug #48564) * During a node restart, logging was enabled on a per-fragment basis as the copying of each fragment was completed but local checkpoints were not enabled until all fragments were copied, making it possible to run out of redo log file space (*Note `NDB': mysql-cluster. error code 410) before the restart was complete. Now logging is enabled only after all fragments has been copied, just prior to enabling local checkpoints. (Bug #48474) * When employing *Note `NDB': mysql-cluster. native backup to back up and restore an empty *Note `NDB': mysql-cluster. table that used a non-sequential `AUTO_INCREMENT' value, the `AUTO_INCREMENT' value was not restored correctly. (Bug #48005) * *Note `ndb_config `--xml' `--configinfo'': mysql-cluster-programs-ndb-config. now indicates that parameters belonging in the `[SCI]', `[SCI DEFAULT]', `[SHM]', and `[SHM DEFAULT]' sections of the `config.ini' file are deprecated or experimental, as appropriate. (Bug #47365) * *Note `NDB': mysql-cluster. stores blob column data in a separate, hidden table that is not accessible from MySQL. If this table was missing for some reason (such as accidental deletion of the file corresponding to the hidden table) when making a MySQL Cluster native backup, ndb_restore crashed when attempting to restore the backup. Now in such cases, ndb_restore fails with the error message `Table TABLE_NAME has blob column (COLUMN_NAME) with missing parts table in backup' instead. (Bug #47289) * *Note `DROP DATABASE': drop-database. failed when there were stale temporary *Note `NDB': mysql-cluster. tables in the database. This situation could occur if *Note `mysqld': mysqld. crashed during execution of a *Note `DROP TABLE': drop-table. statement after the table definition had been removed from *Note `NDBCLUSTER': mysql-cluster. but before the corresponding `.ndb' file had been removed from the crashed SQL node's data directory. Now, when *Note `mysqld': mysqld. executes *Note `DROP DATABASE': drop-database, it checks for these files and removes them if there are no corresponding table definitions for them found in *Note `NDBCLUSTER': mysql-cluster. (Bug #44529) * Creating an *Note `NDB': mysql-cluster. table with an excessive number of large *Note `BIT': numeric-types. columns caused the cluster to fail. Now, an attempt to create such a table is rejected with error 791 (`Too many total bits in bitfields'). (Bug #42046) See also Bug #42047. * When a long-running transaction lasting long enough to cause Error 410 (`REDO log files overloaded') was later committed or rolled back, it could happen that *Note `NDBCLUSTER': mysql-cluster. was not able to release the space used for the REDO log, so that the error condition persisted indefinitely. The most likely cause of such transactions is a bug in the application using MySQL Cluster. This fix should handle most cases where this might occur. (Bug #36500) * Deprecation and usage information obtained from *Note `ndb_config `--configinfo'': mysql-cluster-programs-ndb-config. regarding the `PortNumber' and `ServerPort' configuration parameters was improved. (Bug #24584) * *Disk Data*: When running a write-intensive workload with a very large disk page buffer cache, CPU usage approached 100% during a local checkpoint of a cluster containing Disk Data tables. (Bug #49532) * *Disk Data*: Repeatedly creating and then dropping Disk Data tables could eventually lead to data node failures. (Bug #45794, Bug #48910) * *Disk Data*: When the `FileSystemPathUndoFiles' configuration parameter was set to an non-existent path, the data nodes shut down with the generic error code 2341 (`Internal program error'). Now in such cases, the error reported is error 2815 (`File not found'). * *Cluster API*: When a DML operation failed due to a uniqueness violation on an *Note `NDB': mysql-cluster. table having more than one unique index, it was difficult to determine which constraint caused the failure; it was necessary to obtain an `NdbError' object, then decode its `details' property, which in could lead to memory management issues in application code. To help solve this problem, a new API method `Ndb::getNdbErrorDetail()' is added, providing a well-formatted string containing more precise information about the index that caused the unque constraint violation. The following additional changes are also made in the NDB API: * Use of `NdbError.details' is now deprecated in favor of the new method. * The `NdbDictionary::listObjects()' method has been modified to provide more information. For more information, see `Ndb::getNdbErrorDetail()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndb-methods.html#ndb-ndb-getndberrordetail), The `NdbError' Structure (http://dev.mysql.com/doc/ndbapi/en/ndb-ndberror.html#ndb-ndberror), and `Dictionary::listObjects()' (http://dev.mysql.com/doc/ndbapi/en/ndb-dictionary-methods.html#ndb-dictionary-listobjects). (Bug #48851) * *Cluster API*: When using blobs, calling `getBlobHandle()' requires the full key to have been set using `equal()', because `getBlobHandle()' must access the key for adding blob table operations. However, if `getBlobHandle()' was called without first setting all parts of the primary key, the application using it crashed. Now, an appropriate error code is returned instead. (Bug #28116, Bug #48973) *Changes in MySQL Cluster NDB 6.3.28a (5.1.39-ndb-6.3.28a) * *Bugs fixed:* * When the combined length of all names of tables using the *Note `NDB': mysql-cluster. storage engine was greater than or equal to 1024 bytes, issuing the `START BACKUP' command in the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client caused the cluster to crash. (Bug #48531) *Changes in MySQL Cluster NDB 6.3.27 (5.1.37-ndb-6.3.27) * *Functionality added or changed:* * *Disk Data*: Two new columns have been added to the output of *Note `ndb_desc': mysql-cluster-programs-ndb-desc. to make it possible to determine how much of the disk space allocated to a given table or fragment remains free. (This information is not available from the *Note `INFORMATION_SCHEMA.FILES': files-table. table, since the *Note `FILES': files-table. table applies only to Disk Data files.) For more information, see *Note mysql-cluster-programs-ndb-desc::. (Bug #47131) *Bugs fixed:* * *Note `mysqld': mysqld. allocated an excessively large buffer for handling *Note `BLOB': blob. values due to overestimating their size. (For each row, enough space was allocated to accommodate _every_ *Note `BLOB': blob. or *Note `TEXT': blob. column value in the result set.) This could adversely affect performance when using tables containing *Note `BLOB': blob. or *Note `TEXT': blob. columns; in a few extreme cases, this issue could also cause the host system to run out of memory unexpectedly. (Bug #47574) See also Bug #47572, Bug #47573. * `NDBCLUSTER' uses a dynamically-allocated buffer to store *Note `BLOB': blob. or *Note `TEXT': blob. column data that is read from rows in MySQL Cluster tables. When an instance of the `NDBCLUSTER' table handler was recycled (this can happen due to table definition cache pressure or to operations such as *Note `FLUSH TABLES': flush. or *Note `ALTER TABLE': alter-table.), if the last row read contained blobs of zero length, the buffer was not freed, even though the reference to it was lost. This resulted in a memory leak. For example, consider the table defined and populated as shown here: CREATE TABLE t (a INT PRIMARY KEY, b LONGTEXT) ENGINE=NDB; INSERT INTO t VALUES (1, REPEAT('F', 20000)); INSERT INTO t VALUES (2, ''); Now execute repeatedly a *Note `SELECT': select. on this table, such that the zero-length *Note `LONGTEXT': blob. row is last, followed by a *Note `FLUSH TABLES': flush. statement (which forces the handler object to be re-used), as shown here: SELECT a, length(b) FROM bl ORDER BY a; FLUSH TABLES; Prior to the fix, this resulted in a memory leak proportional to the size of the stored *Note `LONGTEXT': blob. value each time these two statements were executed. (Bug #47573) See also Bug #47572, Bug #47574. * Large transactions involving joins between tables containing *Note `BLOB': blob. columns used excessive memory. (Bug #47572) See also Bug #47573, Bug #47574. * A variable was left uninitialized while a data node copied data from its peers as part of its startup routine; if the starting node died during this phase, this could lead a crash of the cluster when the node was later restarted. (Bug #47505) * When a data node restarts, it first runs the redo log until reaching the latest restorable global checkpoint; after this it scans the remainder of the redo log file, searching for entries that should be invalidated so they are not used in any subsequent restarts. (It is possible, for example, if restoring GCI number 25, that there might be entries belonging to GCI 26 in the redo log.) However, under certain rare conditions, during the invalidation process, the redo log files themselves were not always closed while scanning ahead in the redo log. In rare cases, this could lead to `MaxNoOfOpenFiles' being exceeded, causing a the data node to crash. (Bug #47171) * For very large values of `MaxNoOfTables' + `MaxNoOfAttributes', the calculation for `StringMemory' could overflow when creating large numbers of tables, leading to *Note `NDB': mysql-cluster. error 773 (`Out of string memory, please modify StringMemory config parameter'), even when `StringMemory' was set to `100' (100 percent). (Bug #47170) * The default value for the `StringMemory' configuration parameter, unlike other MySQL Cluster configuration parameters, was not set in `ndb/src/mgmsrv/ConfigInfo.cpp'. (Bug #47166) * Signals from a failed API node could be received after an `API_FAILREQ' signal (see Operations and Signals (http://dev.mysql.com/doc/ndbapi/en/ndb-internals-ndb-protocol-operations-signals.html)) has been received from that node, which could result in invalid states for processing subsequent signals. Now, all pending signals from a failing API node are processed before any `API_FAILREQ' signal is received. (Bug #47039) See also Bug #44607. * Using triggers on *Note `NDB': mysql-cluster. tables caused `ndb_autoincrement_prefetch_sz' to be treated as having the NDB kernel's internal default value (32) and the value for this variable as set on the cluster's SQL nodes to be ignored. (Bug #46712) * Running an *Note `ALTER TABLE': alter-table. statement while an *Note `NDB': mysql-cluster. backup was in progress caused *Note `mysqld': mysqld. to crash. (Bug #44695) * When performing auto-discovery of tables on individual SQL nodes, `NDBCLUSTER' attempted to overwrite existing `MyISAM' `.frm' files and corrupted them. Workaround In the *Note `mysql': mysql. client, create a new table (`t2') with same definition as the corrupted table (`t1'). Use your system shell or file manager to rename the old `.MYD' file to the new file name (for example, `mv t1.MYD t2.MYD'). In the *Note `mysql': mysql. client, repair the new table, drop the old one, and rename the new table using the old file name (for example, *Note `RENAME TABLE t2 TO t1': rename-table.). (Bug #42614) * Running *Note `ndb_restore': mysql-cluster-programs-ndb-restore. with the `--print' or `--print_log' option could cause it to crash. (Bug #40428, Bug #33040) * An insert on an *Note `NDB': mysql-cluster. table was not always flushed properly before performing a scan. One way in which this issue could manifest was that `LAST_INSERT_ID()' sometimes failed to return correct values when using a trigger on an *Note `NDB': mysql-cluster. table. (Bug #38034) * When a data node received a `TAKE_OVERTCCONF' signal from the master before that node had received a `NODE_FAILREP', a race condition could in theory result. (Bug #37688) See also Bug #25364, Bug #28717. * Some joins on large *Note `NDB': mysql-cluster. tables having *Note `TEXT': blob. or *Note `BLOB': blob. columns could cause *Note `mysqld': mysqld. processes to leak memory. The joins did not need to reference the *Note `TEXT': blob. or *Note `BLOB': blob. columns directly for this issue to occur. (Bug #36701) * On Mac OS X 10.5, commands entered in the management client failed and sometimes caused the client to hang, although management client commands invoked using the `--execute' (or `-e') option from the system shell worked normally. For example, the following command failed with an error and hung until killed manually, as shown here: ndb_mgm> SHOW `Warning, event thread startup failed, degraded printouts as result, errno=36' ^C However, the same management client command, invoked from the system shell as shown here, worked correctly: shell> ndb_mgm -e "SHOW" (Bug #35751) See also Bug #34438. * *Disk Data*: Calculation of free space for Disk Data table fragments was sometimes done incorrectly. This could lead to unnecessary allocation of new extents even when sufficient space was available in existing ones for inserted data. In some cases, this might also lead to crashes when restarting data nodes. *Note*: This miscalculation was not reflected in the contents of the *Note `INFORMATION_SCHEMA.FILES': files-table. table, as it applied to extents allocated to a fragment, and not to a file. (Bug #47072) * *Cluster API*: In some circumstances, if an API node encountered a data node failure between the creation of a transaction and the start of a scan using that transaction, then any subsequent calls to `startTransaction()' and `closeTransaction()' could cause the same transaction to be started and closed repeatedly. (Bug #47329) * *Cluster API*: Performing multiple operations using the same primary key within the same `NdbTransaction::execute()' call could lead to a data node crash. *Note*: This fix does not make change the fact that performing multiple operations using the same primary key within the same `execute()' is not supported; because there is no way to determine the order of such operations, the result of such combined operations remains undefined. (Bug #44065) See also Bug #44015. *Changes in MySQL Cluster NDB 6.3.26 (5.1.35-ndb-6.3.26) * *Functionality added or changed:* * On Solaris platforms, the MySQL Cluster management server and NDB API applications now use `CLOCK_REALTIME' as the default clock. (Bug #46183) * A new option `--exclude-missing-columns' has been added for the *Note `ndb_restore': mysql-cluster-programs-ndb-restore. program. In the event that any tables in the database or databases being restored to have fewer columns than the same-named tables in the backup, the extra columns in the backup's version of the tables are ignored. For more information, see *Note mysql-cluster-programs-ndb-restore::. (Bug #43139) * *Note*: This issue, originally resolved in MySQL 5.1.16, re-occurred due to a later (unrelated) change. The fix has been re-applied. (Bug #25984) *Bugs fixed:* * Restarting the cluster following a local checkpoint and an online *Note `ALTER TABLE': alter-table. on a non-empty table caused data nodes to crash. (Bug #46651) * Full table scans failed to execute when the cluster contained more than 21 table fragments. *Note*: The number of table fragments in the cluster can be calculated as the number of data nodes, times 8 (that is, times the value of the internal constant `MAX_FRAG_PER_NODE'), divided by the number of replicas. Thus, when `NoOfReplicas = 1' at least 3 data nodes were required to trigger this issue, and when `NoOfReplicas = 2' at least 4 data nodes were required to do so. (Bug #46490) * Killing MySQL Cluster nodes immediately following a local checkpoint could lead to a crash of the cluster when later attempting to perform a system restart. The exact sequence of events causing this issue was as follows: 1. Local checkpoint occurs. 2. Immediately following the LCP, kill the master data node. 3. Kill the remaining data nodes within a few seconds of killing the master. 4. Attempt to restart the cluster. (Bug #46412) * Ending a line in the `config.ini' file with an extra semicolon character (`;') caused reading the file to fail with a parsing error. (Bug #46242) * When combining an index scan and a delete with a primary key delete, the index scan and delete failed to initialize a flag properly. This could in rare circumstances cause a data node to crash. (Bug #46069) * *Note `OPTIMIZE TABLE': optimize-table. on an *Note `NDB': mysql-cluster. table could in some cases cause SQL and data nodes to crash. This issue was observed with both *Note `ndbd': mysql-cluster-programs-ndbd. and *Note `ndbmtd': mysql-cluster-programs-ndbmtd. (Bug #45971) * The `AutoReconnect' configuration parameter for API nodes (including SQL nodes) has been added. This is intended to prevent API nodes from re-using allocated node IDs during cluster restarts. For more information, see *Note mysql-cluster-api-definition::. This fix also introduces two new methods of the NDB API `Ndb_cluster_connection' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndb-cluster-connection.html#ndb-ndb-cluster-connection) class: `set_auto_reconnect()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndb-cluster-connection-methods.html#ndb-ndb-cluster-connection-set-auto-reconnect) and `get_auto_reconnect()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndb-cluster-connection-methods.html#ndb-ndb-cluster-connection-get-auto-reconnect). (Bug #45921) * The signals used by *Note `ndb_restore': mysql-cluster-programs-ndb-restore. to send progress information about backups to the cluster log accessed the cluster transporter without using any locks. Because of this, it was theoretically possible that these signals could be interefered with by heartbeat signals if both were sent at the same time, causing the *Note `ndb_restore': mysql-cluster-programs-ndb-restore. messages to be corrupted. (Bug #45646) * Problems could arise when using *Note `VARCHAR': char. columns whose size was greater than 341 characters and which used the `utf8_unicode_ci' collation. In some cases, this combination of conditions could cause certain queries and *Note `OPTIMIZE TABLE': optimize-table. statements to crash *Note `mysqld': mysqld. (Bug #45053) * An internal NDB API buffer was not properly initialized. (Bug #44977) * When a data node had written its GCI marker to the first page of a megabyte, and that node was later killed during restart after having processed that page (marker) but before completing a LCP, the data node could fail with file system errors. (Bug #44952) See also Bug #42564, Bug #44291. * The warning message `Possible bug in Dbdih::execBLOCK_COMMIT_ORD ...' could sometimes appear in the cluster log. This warning is obsolete, and has been removed. (Bug #44563) * In some cases, *Note `OPTIMIZE TABLE': optimize-table. on an *Note `NDB': mysql-cluster. table did not free any `DataMemory'. (Bug #43683) * If the cluster crashed during the execution of a *Note `CREATE LOGFILE GROUP': create-logfile-group. statement, the cluster could not be restarted afterward. (Bug #36702) See also Bug #34102. * *Disk Data*: *Partitioning*: An *Note `NDB': mysql-cluster. table created with a very large value for the `MAX_ROWS' option could--if this table was dropped and a new table with fewer partitions, but having the same table ID, was created--cause *Note `ndbd': mysql-cluster-programs-ndbd. to crash when performing a system restart. This was because the server attempted to examine each partition whether or not it actually existed. (Bug #45154) See also Bug #58638. * *Disk Data*: If the value set in the `config.ini' file for `FileSystemPathDD', `FileSystemPathDataFiles', or `FileSystemPathUndoFiles' was identical to the value set for `FileSystemPath', that parameter was ignored when starting the data node with `--initial' option. As a result, the Disk Data files in the corresponding directory were not removed when performing an initial start of the affected data node or data nodes. (Bug #46243) * *Disk Data*: During a checkpoint, restore points are created for both the on-disk and in-memory parts of a Disk Data table. Under certain rare conditions, the in-memory restore point could include or exclude a row that should have been in the snapshot. This would later lead to a crash during or following recovery. (Bug #41915) See also Bug #47832. *Changes in MySQL Cluster NDB 6.3.25 (5.1.34-ndb-6.3.25) * *Functionality added or changed:* * Two new server status variables `Ndb_scan_count' and `Ndb_pruned_scan_count' have been introduced. `Ndb_scan_count' gives the number of scans executed since the cluster was last started. `Ndb_pruned_scan_count' gives the number of scans for which *Note `NDBCLUSTER': mysql-cluster. was able to use partition pruning. Together, these variables can be used to help determine in the MySQL server whether table scans are pruned by *Note `NDBCLUSTER': mysql-cluster. (Bug #44153) * The *Note `ndb_config': mysql-cluster-programs-ndb-config. utility program can now provide an offline dump of all MySQL Cluster configuration parameters including information such as default and permitted values, brief description, and applicable section of the `config.ini' file. A dump in text format is produced when running *Note `ndb_config': mysql-cluster-programs-ndb-config. with the new `--configinfo' option, and in XML format when the options `--configinfo --xml' are used together. For more information and examples, see *Note mysql-cluster-programs-ndb-config::. *Bugs fixed:* * *Important Change*: *Partitioning*: User-defined partitioning of an *Note `NDBCLUSTER': mysql-cluster. table without any primary key sometimes failed, and could cause *Note `mysqld': mysqld. to crash. Now, if you wish to create an *Note `NDBCLUSTER': mysql-cluster. table with user-defined partitioning, the table must have an explicit primary key, and all columns listed in the partitioning expression must be part of the primary key. The hidden primary key used by the *Note `NDBCLUSTER': mysql-cluster. storage engine is not sufficient for this purpose. However, if the list of columns is empty (that is, the table is defined using `PARTITION BY [LINEAR] KEY()'), then no explicit primary key is required. This change does not effect the partitioning of tables using any storage engine other than *Note `NDBCLUSTER': mysql-cluster. (Bug #40709) * *Important Change*: Previously, the configuration parameter `NoOfReplicas' had no default value. Now the default for `NoOfReplicas' is 2, which is the recommended value in most settings. (Bug #44746) * *Packaging*: The `pkg' installer for MySQL Cluster on Solaris did not perform a complete installation due to an invalid directory reference in the postinstall script. (Bug #41998) * When *Note `ndb_config': mysql-cluster-programs-ndb-config. could not find the file referenced by the `--config-file' option, it tried to read `my.cnf' instead, then failed with a misleading error message. (Bug #44846) * When a data node was down so long that its most recent local checkpoint depended on a global checkpoint that was no longer restorable, it was possible for it to be unable to use optimized node recovery when being restarted later. (Bug #44844) See also Bug #26913. * *Note `ndb_config `--xml'': mysql-cluster-programs-ndb-config. did not output any entries for the `HostName' parameter. In addition, the default listed for `MaxNoOfFiles' was outside the permitted range of values. (Bug #44749) See also Bug #44685, Bug #44746. * The output of *Note `ndb_config `--xml'': mysql-cluster-programs-ndb-config. did not provide information about all sections of the configuration file. (Bug #44685) See also Bug #44746, Bug #44749. * Inspection of the code revealed that several assignment operators (`=') were used in place of comparison operators (`==') in `DbdihMain.cpp'. (Bug #44567) See also Bug #44570. * It was possible for NDB API applications to insert corrupt data into the database, which could subquently lead to data node crashes. Now, stricter checking is enforced on input data for inserts and updates. (Bug #44132) * *Note `ndb_restore': mysql-cluster-programs-ndb-restore. failed when trying to restore data on a big-endian machine from a backup file created on a little-endian machine. (Bug #44069) * The file `ndberror.c' contained a C++-style comment, which caused builds to fail with some C compilers. (Bug #44036) * When trying to use a data node with an older version of the management server, the data node crashed on startup. (Bug #43699) * In some cases, data node restarts during a system restart could fail due to insufficient redo log space. (Bug #43156) * *Note `NDBCLUSTER': mysql-cluster. did not build correctly on Solaris 9 platforms. (Bug #39080) See also Bug #39036, Bug #39038. * *Note `ndb_restore `--print_data'': mysql-cluster-programs-ndb-restore. did not handle *Note `DECIMAL': numeric-types. columns correctly. (Bug #37171) * The output of *Note `ndbd `--help'': mysql-cluster-programs-ndbd. did not provide clear information about the program's `--initial' and `--initial-start' options. (Bug #28905) * It was theoretically possible for the value of a nonexistent column to be read as `NULL', rather than causing an error. (Bug #27843) * *Disk Data*: This fix supercedes and improves on an earlier fix made for this bug in MySQL 5.1.18. (Bug #24521) *Changes in MySQL Cluster NDB 6.3.24 (5.1.32-ndb-6.3.24) * *Bugs fixed:* * *Cluster Replication*: If data node failed during an event creation operation, there was a slight risk that a surviving data node could send an invalid table reference back to NDB, causing the operation to fail with a false Error 723 (`No such table'). This could take place when a data node failed as a *Note `mysqld': mysqld. process was setting up MySQL Cluster Replication. (Bug #43754) * *Cluster API*: Partition pruning did not work correctly for queries involving multiple range scans. As part of the fix for this issue, several improvements have been made in the NDB API, including the addition of a new `NdbScanOperation::getPruned()' method, a new variant of `NdbIndexScanOperation::setBound()', and a new `PartitionSpec' data structure. (Bug #37934) * *Cluster API*: Partition pruning did not work correctly for queries involving multiple range scans. As part of the fix for this issue, several improvements have been made in the NDB API, including the addition of a new `NdbScanOperation::getPruned()' method, a new variant of `NdbIndexScanOperation::setBound()', and a new `PartitionSpec' data structure. (Bug #37934) * `TransactionDeadlockDetectionTimeout' values less than 100 were treated as 100. This could cause scans to time out unexpectedly. (Bug #44099) * A race condition could occur when a data node failed to restart just before being included in the next global checkpoint. This could cause other data nodes to fail. (Bug #43888) * `TimeBetweenLocalCheckpoints' was measured from the end of one local checkpoint to the beginning of the next, rather than from the beginning of one LCP to the beginning of the next. This meant that the time spent performing the LCP was not taken into account when determining the `TimeBetweenLocalCheckpoints' interval, so that LCPs were not started often enough, possibly causing data nodes to run out of redo log space prematurely. (Bug #43567) * Using indexes containing variable-sized columns could lead to internal errors when the indexes were being built. (Bug #43226) * When a data node process had been killed after allocating a node ID, but before making contact with any other data node processes, it was not possible to restart it due to a node ID allocation failure. This issue could effect either *Note `ndbd': mysql-cluster-programs-ndbd. or *Note `ndbmtd': mysql-cluster-programs-ndbmtd. processes. (Bug #43224) This regression was introduced by Bug #42973. * Some queries using combinations of logical and comparison operators on an indexed column in the `WHERE' clause could fail with the error `Got error 4541 'IndexBound has no bound information' from NDBCLUSTER'. (Bug #42857) * *Note `ndb_restore': mysql-cluster-programs-ndb-restore. crashed when trying to restore a backup made to a MySQL Cluster running on a platform having different endianness from that on which the original backup was taken. (Bug #39540) * When aborting an operation involving both an insert and a delete, the insert and delete were aborted separately. This was because the transaction coordinator did not know that the operations affected on same row, and, in the case of a committed-read (tuple or index) scan, the abort of the insert was performed first, then the row was examined after the insert was aborted but before the delete was aborted. In some cases, this would leave the row in a inconsistent state. This could occur when a local checkpoint was performed during a backup. This issue did not affect primary ley operations or scans that used locks (these are serialized). After this fix, for ordered indexes, all operations that follow the operation to be aborted are now also aborted. * *Disk Data*: When a log file group had an undo log file whose size was too small, restarting data nodes failed with `Read underflow' errors. As a result of this fix, the minimum permitted `INTIAL_SIZE' for an undo log file is now `1M' (1 megabyte). (Bug #29574) * *Cluster API*: If the largest offset of a `RecordSpecification' used for an `NdbRecord' object was for the `NULL' bits (and thus not a column), this offset was not taken into account when calculating the size used for the `RecordSpecification'. This meant that the space for the `NULL' bits could be overwritten by key or other information. (Bug #43891) * *Cluster API*: *Note `BIT': numeric-types. columns created using the native NDB API format that were not created as nullable could still sometimes be overwritten, or cause other columns to be overwritten. This issue did not effect tables having *Note `BIT': numeric-types. columns created using the mysqld format (always used by MySQL Cluster SQL nodes). (Bug #43802) * *Cluster API*: The default `NdbRecord' structures created by `NdbDictionary' could have overlapping null bits and data fields. (Bug #43590) * *Cluster API*: When performing insert or write operations, `NdbRecord' permits key columns to be specified in both the key record and in the attribute record. Only one key column value for each key column should be sent to the NDB kernel, but this was not guaranteed. This is now ensured as follows: For insert and write operations, key column values are taken from the key record; for scan takeover update operations, key column values are taken from the attribute record. (Bug #42238) * *Cluster API*: Ordered index scans using `NdbRecord' formerly expressed a `BoundEQ' range as separate lower and upper bounds, resulting in 2 copies of the column values being sent to the NDB kernel. Now, when a range is specified by `NdbScanOperation::setBound()', the passed pointers, key lengths, and inclusive bits are compared, and only one copy of the equal key columns is sent to the kernel. This makes such operations more efficient, as half the amount of `KeyInfo' is now sent for a `BoundEQ' range as before. (Bug #38793) *Changes in MySQL Cluster NDB 6.3.23 (5.1.32-ndb-6.3.23) * *Functionality added or changed:* * A new data node configuration parameter `MaxLCPStartDelay' has been introduced to facilitate parallel node recovery by causing a local checkpoint to be delayed while recovering nodes are synchronizing data dictionaries and other meta-information. For more information about this parameter, see *Note mysql-cluster-ndbd-definition::. (Bug #43053) *Bugs fixed:* * *Performance*: Updates of the `SYSTAB_0' system table to obtain a unique identifier did not use transaction hints for tables having no primary key. In such cases the NDB kernel used a cache size of 1. This meant that each insert into a table not having a primary key required an update of the corresponding `SYSTAB_0' entry, creating a potential performance bottleneck. With this fix, inserts on `NDB' tables without primary keys can be under some conditions be performed up to 100% faster than previously. (Bug #39268) * *Packaging*: Packages for MySQL Cluster were missing the `libndbclient.so' and `libndbclient.a' files. (Bug #42278) * *Partitioning*: Executing `ALTER TABLE ... REORGANIZE PARTITION' on an *Note `NDBCLUSTER': mysql-cluster. table having only one partition caused *Note `mysqld': mysqld. to crash. (Bug #41945) See also Bug #40389. * Backup IDs greater than 2^31 were not handled correctly, causing negative values to be used in backup directory names and printouts. (Bug #43042) * When using *Note `ndbmtd': mysql-cluster-programs-ndbmtd, NDB kernel threads could hang while trying to start the data nodes with `LockPagesInMainMemory' set to 1. (Bug #43021) * When using multiple management servers and starting several API nodes (possibly including one or more SQL nodes) whose connectstrings listed the management servers in different order, it was possible for 2 API nodes to be assigned the same node ID. When this happened it was possible for an API node not to get fully connected, consequently producing a number of errors whose cause was not easily recognizable. (Bug #42973) * *Note `ndb_error_reporter': mysql-cluster-programs-ndb-error-reporter. worked correctly only with GNU `tar'. (With other versions of `tar', it produced empty archives.) (Bug #42753) * Triggers on *Note `NDBCLUSTER': mysql-cluster. tables caused such tables to become locked. (Bug #42751) See also Bug #16229, Bug #18135. * Given a MySQL Cluster containing no data (that is, whose data nodes had all been started using `--initial', and into which no data had yet been imported) and having an empty backup directory, executing `START BACKUP' with a user-specified backup ID caused the data nodes to crash. (Bug #41031) * In some cases, *Note `NDB': mysql-cluster. did not check correctly whether tables had changed before trying to use the query cache. This could result in a crash of the debug MySQL server. (Bug #40464) * *Disk Data*: It was not possible to add an in-memory column online to a table that used a table-level or column-level `STORAGE DISK' option. The same issue prevented `ALTER ONLINE TABLE ... REORGANIZE PARTITION' from working on Disk Data tables. (Bug #42549) * *Disk Data*: Creating a Disk Data tablespace with a very large extent size caused the data nodes to fail. The issue was observed when using extent sizes of 100 MB and larger. (Bug #39096) * *Disk Data*: Trying to execute a *Note `CREATE LOGFILE GROUP': create-logfile-group. statement using a value greater than `150M' for `UNDO_BUFFER_SIZE' caused data nodes to crash. As a result of this fix, the upper limit for `UNDO_BUFFER_SIZE' is now `600M'; attempting to set a higher value now fails gracefully with an error. (Bug #34102) See also Bug #36702. * *Disk Data*: When attempting to create a tablespace that already existed, the error message returned was `Table or index with given name already exists'. (Bug #32662) * *Disk Data*: Using a path or filename longer than 128 characters for Disk Data undo log files and tablespace data files caused a number of issues, including failures of *Note `CREATE LOGFILE GROUP': create-logfile-group, *Note `ALTER LOGFILE GROUP': alter-logfile-group, *Note `CREATE TABLESPACE': create-tablespace, and *Note `ALTER TABLESPACE': alter-tablespace. statements, as well as crashes of management nodes and data nodes. With this fix, the maximum length for path and file names used for Disk Data undo log files and tablespace data files is now the same as the maximum for the operating system. (Bug #31769, Bug #31770, Bug #31772) * *Disk Data*: Attempting to perform a system restart of the cluster where there existed a logfile group without and undo log files caused the data nodes to crash. *Note*: While issuing a *Note `CREATE LOGFILE GROUP': create-logfile-group. statement without an `ADD UNDOFILE' option fails with an error in the MySQL server, this situation could arise if an SQL node failed during the execution of a valid *Note `CREATE LOGFILE GROUP': create-logfile-group. statement; it is also possible to create a logfile group without any undo log files using the NDB API. (Bug #17614) * *Cluster API*: Some error messages from *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. contained newline (`\n') characters. This could break the MGM API protocol, which uses the newline as a line separator. (Bug #43104) * *Cluster API*: When using an ordered index scan without putting all key columns in the read mask, this invalid use of the NDB API went undetected, which resulted in the use of uninitialized memory. (Bug #42591) *Changes in MySQL Cluster NDB 6.3.22 (5.1.31-ndb-6.3.22) * *Functionality added or changed:* * New options are introduced for *Note `ndb_restore': mysql-cluster-programs-ndb-restore. for determining which tables or databases should be restored: * `--include-tables' and `--include-databases' can be used to restore specific tables or databases. * `--exclude-tables' and `--exclude-databases' can be used to exclude the specified tables or databases from being restored. For more information about these options, see *Note mysql-cluster-programs-ndb-restore::. (Bug #40429) *Bugs fixed:* * When performing more than 32 index or tuple scans on a single fragment, the scans could be left hanging. This caused unnecessary timeouts, and in addition could possibly lead to a hang of an LCP. (Bug #42559) * A data node failure that occurred between calls to `NdbIndexScanOperation::readTuples(SF_OrderBy)' and `NdbTransaction::execute()' was not correctly handled; a subsequent call to `nextResult()' caused a null pointer to be deferenced, leading to a segfault in *Note `mysqld': mysqld. (Bug #42545) * Issuing `SHOW GLOBAL STATUS LIKE 'NDB%'' before *Note `mysqld': mysqld. had connected to the cluster caused a segmentation fault. (Bug #42458) * Data node failures that occurred before all data nodes had connected to the cluster were not handled correctly, leading to additional data node failures. (Bug #42422) * When a cluster backup failed with Error 1304 (Node NODE_ID1: Backup request from NODE_ID2 failed to start), no clear reason for the failure was provided. As part of this fix, MySQL Cluster now retries backups in the event of sequence errors. (Bug #42354) See also Bug #22698. * Issuing *Note `SHOW ENGINE NDBCLUSTER STATUS': show-engine. on an SQL node before the management server had connected to the cluster caused *Note `mysqld': mysqld. to crash. (Bug #42264) *Changes in MySQL Cluster NDB 6.3.21 (5.1.31-ndb-6.3.21) * *Functionality added or changed:* * *Important Change*: Formerly, when the management server failed to create a transporter for a data node connection, `net_write_timeout' seconds elapsed before the data node was actually permitted to disconnect. Now in such cases the disconnection occurs immediately. (Bug #41965) See also Bug #41713. * It is now possible while in Single User Mode to restart all data nodes using `ALL RESTART' in the management client. Restarting of individual nodes while in Single User Mode remains not permitted. (Bug #31056) * Formerly, when using MySQL Cluster Replication, records for `empty' epochs--that is, epochs in which no changes to *Note `NDBCLUSTER': mysql-cluster. data or tables took place--were inserted into the `ndb_apply_status' and `ndb_binlog_index' tables on the slave even when `--log-slave-updates' was disabled. Beginning with MySQL Cluster NDB 6.2.16 and MySQL Cluster NDB 6.3.13 this was changed so that these `empty' eopchs were no longer logged. However, it is now possible to re-enable the older behavior (and cause `empty' epochs to be logged) by using the `--ndb-log-empty-epochs' option. For more information, see *Note replication-options-slave::. See also Bug #37472. *Bugs fixed:* * A maximum of 11 `TUP' scans were permitted in parallel. (Bug #42084) * Trying to execute an *Note `ALTER ONLINE TABLE ... ADD COLUMN': alter-table. statement while inserting rows into the table caused *Note `mysqld': mysqld. to crash. (Bug #41905) * If the master node failed during a global checkpoint, it was possible in some circumstances for the new master to use an incorrect value for the global checkpoint index. This could occur only when the cluster used more than one node group. (Bug #41469) * API nodes disconnected too agressively from cluster when data nodes were being restarted. This could sometimes lead to the API node being unable to access the cluster at all during a rolling restart. (Bug #41462) * It was not possible to perform online upgrades from a MySQL Cluster NDB 6.2 release to MySQL Cluster NDB 6.3.8 or a later MySQL Cluster NDB 6.3 release. (Bug #41435) * Cluster log files were opened twice by internal log-handling code, resulting in a resource leak. (Bug #41362) * An abort path in the `DBLQH' kernel block failed to release a commit acknowledgment marker. This meant that, during node failure handling, the local query handler could be added multiple times to the marker record which could lead to additional node failures due an array overflow. (Bug #41296) * During node failure handling (of a data node other than the master), there was a chance that the master was waiting for a `GCP_NODEFINISHED' signal from the failed node after having received it from all other data nodes. If this occurred while the failed node had a transaction that was still being committed in the current epoch, the master node could crash in the `DBTC' kernel block when discovering that a transaction actually belonged to an epoch which was already completed. (Bug #41295) * Issuing `EXIT' in the management client sometimes caused the client to hang. (Bug #40922) * In the event that a MySQL Cluster backup failed due to file permissions issues, conflicting reports were issued in the management client. (Bug #34526) * If all data nodes were shut down, MySQL clients were unable to access *Note `NDBCLUSTER': mysql-cluster. tables and data even after the data nodes were restarted, unless the MySQL clients themselves were restarted. (Bug #33626) * *Disk Data*: Starting a cluster under load such that Disk Data tables used most of the undo buffer could cause data node failures. The fix for this bug also corrected an issue in the `LGMAN' kernel block where the amount of free space left in the undo buffer was miscalculated, causing buffer overruns. This could cause records in the buffer to be overwritten, leading to problems when restarting data nodes. (Bug #28077) * *Cluster API*: `mgmapi.h' contained constructs which only worked in C++, but not in C. (Bug #27004) *Changes in MySQL Cluster NDB 6.3.20 (5.1.30-ndb-6.3.20) * *Functionality added or changed:* * *Cluster API*: Two new `Ndb_cluster_connection' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndb-cluster-connection.html#ndb-ndb-cluster-connection) methods have been added to help in diagnosing problems with NDB API client connections. The `get_latest_error()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndb-cluster-connection-methods.html#ndb-ndb-cluster-connection-get-latest-error) method tells whether or not the latest connection attempt succeeded; if the attempt failed, `get_latest_error_msg()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndb-cluster-connection-methods.html#ndb-ndb-cluster-connection-get-latest-error-msg) provides an error message giving the reason. *Bugs fixed:* * If a transaction was aborted during the handling of a data node failure, this could lead to the later handling of an API node failure not being completed. (Bug #41214) * Issuing `SHOW TABLES' repeatedly could cause *Note `NDBCLUSTER': mysql-cluster. tables to be dropped. (Bug #40854) * Statements of the form `UPDATE ... ORDER BY ... LIMIT' run against *Note `NDBCLUSTER': mysql-cluster. tables failed to update all matching rows, or failed with the error `Can't find record in 'TABLE_NAME''. (Bug #40081) * Start phase reporting was inconsistent between the management client and the cluster log. (Bug #39667) * Status messages shown in the management client when restarting a management node were inappropriate and misleading. Now, when restarting a management node, the messages displayed are as follows, where NODE_ID is the management node's node ID: ndb_mgm> NODE_ID RESTART Shutting down MGM node NODE_ID for restart Node NODE_ID is being restarted ndb_mgm> (Bug #29275) * *Disk Data*: This improves on a previous fix for this issue that was made in MySQL Cluster 6.3.8. (Bug #37116) See also Bug #29186. * *Cluster API*: When creating a scan using an `NdbScanFilter' object, it was possible to specify conditions against a `BIT' column, but the correct rows were not returned when the scan was executed. As part of this fix, 4 new comparison operators have been implemented for use with scans on `BIT' columns: * `COL_AND_MASK_EQ_MASK' * `COL_AND_MASK_NE_MASK' * `COL_AND_MASK_EQ_ZERO' * `COL_AND_MASK_NE_ZERO' For more information about these operators, see The `NdbScanFilter::BinaryCondition' Type (http://dev.mysql.com/doc/ndbapi/en/ndb-ndbscanfilter-types.html#ndb-ndbscanfilter-binarycondition). Equivalent methods are now also defined for `NdbInterpretedCode'; for more information, see `NdbInterpretedCode' Bitwise Comparison Operations (http://dev.mysql.com/doc/ndbapi/en/ndb-ndbinterpretedcode-methods.html#ndb-ndbinterpretedcode-bitwise-comparisons). (Bug #40535) *Changes in MySQL Cluster NDB 6.3.19 (5.1.29-ndb-6.3.19) * *Functionality added or changed:* * *Cluster API*: *Important Change*: MGM API applications exited without raising any errors if the connection to the management server was lost. The fix for this issue includes two changes: 1. The MGM API now provides its own `SIGPIPE' handler to catch the `broken pipe' error that occurs when writing to a closed or reset socket. This means that MGM API now behaves the same as NDB API in this regard. 2. A new function `ndb_mgm_set_ignore_sigpipe()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-set-ignore-sigpipe.html) has been added to the MGM API. This function makes it possible to bypass the `SIGPIPE' handler provded by the MGM API. (Bug #40498) * When performing an initial start of a data node, fragment log files were always created sparsely--that is, not all bytes were written. Now it is possible to override this behavior using the new `InitFragmentLogFiles' configuration parameter. (Bug #40847) *Bugs fixed:* * *Cluster API*: Failed operations on *Note `BLOB': blob. and *Note `TEXT': blob. columns were not always reported correctly to the originating SQL node. Such errors were sometimes reported as being due to timeouts, when the actual problem was a transporter overload due to insufficient buffer space. (Bug #39867, Bug #39879) * *Cluster API*: Failed operations on *Note `BLOB': blob. and *Note `TEXT': blob. columns were not always reported correctly to the originating SQL node. Such errors were sometimes reported as being due to timeouts, when the actual problem was a transporter overload due to insufficient buffer space. (Bug #39867, Bug #39879) * Undo logs and data files were created in 32K increments. Now these files are created in 512K increments, resulting in shorter creation times. (Bug #40815) * Redo log creation was very slow on some platforms, causing MySQL Cluster to start more slowly than necessary with some combinations of hardware and operating system. This was due to all write operations being synchronized to disk while creating a redo log file. Now this synchronization occurs only after the redo log has been created. (Bug #40734) * Transaction failures took longer to handle than was necessary. When a data node acting as transaction coordinator (TC) failed, the surviving data nodes did not inform the API node initiating the transaction of this until the failure had been processed by all protocols. However, the API node needed only to know about failure handling by the transaction protocol--that is, it needed to be informed only about the TC takeover process. Now, API nodes (including MySQL servers acting as cluster SQL nodes) are informed as soon as the TC takeover is complete, so that it can carry on operating more quickly. (Bug #40697) * It was theoretically possible for stale data to be read from *Note `NDBCLUSTER': mysql-cluster. tables when the transaction isolation level was set to `ReadCommitted'. (Bug #40543) * The `LockExecuteThreadToCPU' and `LockMaintThreadsToCPU' parameters did not work on Solaris. (Bug #40521) * `SET SESSION ndb_optimized_node_selection = 1' failed with an invalid warning message. (Bug #40457) * A restarting data node could fail with an error in the `DBDIH' kernel block when a local or global checkpoint was started or triggered just as the node made a request for data from another data node. (Bug #40370) * Restoring a MySQL Cluster from a dump made using *Note `mysqldump': mysqldump. failed due to a spurious error: `Can't execute the given command because you have active locked tables or an active transaction'. (Bug #40346) * `O_DIRECT' was incorrectly disabled when making MySQL Cluster backups. (Bug #40205) * Heavy DDL usage caused the *Note `mysqld': mysqld. processes to hang due to a timeout error (*Note `NDB': mysql-cluster. error code 266). (Bug #39885) * Executing *Note `EXPLAIN SELECT': explain. on an *Note `NDBCLUSTER': mysql-cluster. table could cause *Note `mysqld': mysqld. to crash. (Bug #39872) * Events logged after setting `ALL CLUSTERLOG STATISTICS=15' in the management client did not always include the node ID of the reporting node. (Bug #39839) * The MySQL Query Cache did not function correctly with *Note `NDBCLUSTER': mysql-cluster. tables containing *Note `TEXT': blob. columns. (Bug #39295) * A segfault in `Logger::Log' caused *Note `ndbd': mysql-cluster-programs-ndbd. to hang indefinitely. This fix improves on an earlier one for this issue, first made in MySQL Cluster NDB 6.2.16 and MySQL Cluster NDB 6.3.17. (Bug #39180) See also Bug #38609. * Memory leaks could occur in handling of strings used for storing cluster metadata and providing output to users. (Bug #38662) * A duplicate key or other error raised when inserting into an *Note `NDBCLUSTER': mysql-cluster. table caused the current transaction to abort, after which any SQL statement other than a *Note `ROLLBACK': commit. failed. With this fix, the *Note `NDBCLUSTER': mysql-cluster. storage engine now performs an implicit rollback when a transaction is aborted in this way; it is no longer necessary to issue an explicit *Note `ROLLBACK': commit. statement, and the next statement that is issued automatically begins a new transaction. *Note*: It remains necessary in such cases to retry the complete transaction, regardless of which statement caused it to be aborted. (Bug #32656) See also Bug #47654. * Error messages for *Note `NDBCLUSTER': mysql-cluster. error codes 1224 and 1227 were missing. (Bug #28496) * *Disk Data*: Issuing concurrent *Note `CREATE TABLESPACE': create-tablespace, *Note `ALTER TABLESPACE': alter-tablespace, *Note `CREATE LOGFILE GROUP': create-logfile-group, or *Note `ALTER LOGFILE GROUP': alter-logfile-group. statements on separate SQL nodes caused a resource leak that led to data node crashes when these statements were used again later. (Bug #40921) * *Disk Data*: Disk-based variable-length columns were not always handled like their memory-based equivalents, which could potentially lead to a crash of cluster data nodes. (Bug #39645) * *Disk Data*: `O_SYNC' was incorrectly disabled on platforms that do not support `O_DIRECT'. This issue was noted on Solaris but could have affected other platforms not having `O_DIRECT' capability. (Bug #34638) * *Cluster API*: The MGM API reset error codes on management server handles before checking them. This meant that calling an MGM API function with a null handle caused applications to crash. (Bug #40455) * *Cluster API*: It was not always possible to access parent objects directly from `NdbBlob', `NdbOperation', and `NdbScanOperation' objects. To alleviate this problem, a new `getNdbOperation()' method has been added to `NdbBlob' and new getNdbTransaction() methods have been added to `NdbOperation' and `NdbScanOperation'. In addition, a const variant of `NdbOperation::getErrorLine()' is now also available. (Bug #40242) * *Cluster API*: `NdbScanOperation::getBlobHandle()' failed when used with incorrect column names or numbers. (Bug #40241) * *Cluster API*: The MGM API function `ndb_mgm_listen_event()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-listen-event.html) ignored bind addresses. As part of this fix, it is now possible to specify bind addresses in connectstrings. See *Note mysql-cluster-connectstring::, for more information. (Bug #38473) * *Cluster API*: The NDB API example programs included in MySQL Cluster source distributions failed to compile. (Bug #37491) See also Bug #40238. *Changes in MySQL Cluster NDB 6.3.18 (5.1.28-ndb-6.3.18) * *Functionality added or changed:* * It is no longer a requirement for database autodiscovery that an SQL node already be connected to the cluster at the time that a database is created on another SQL node. It is no longer necessary to issue *Note `CREATE DATABASE': create-database. (or *Note `CREATE SCHEMA': create-database.) statements on an SQL node joining the cluster after a database is created for the new SQL node to see the database and any `NDCLUSTER' tables that it contains. (Bug #39612) *Bugs fixed:* * When a transaction included a multi-row insert to an *Note `NDBCLUSTER': mysql-cluster. table that caused a constraint violation, the transaction failed to roll back. (Bug #395638) * Starting the MySQL Server with the `--ndbcluster' option plus an invalid command-line option (for example, using *Note `mysqld': mysqld. `--ndbcluster --foobar') caused it to hang while shutting down the binlog thread. (Bug #39635) * Dropping and then re-creating a database on one SQL node caused other SQL nodes to hang. (Bug #39613) * Setting a low value of `MaxNoOfLocalScans' (< 100) and performing a large number of (certain) scans could cause the Transaction Coordinator to run out of scan fragment records, and then crash. Now when this resource is exhausted, the cluster returns Error 291 (`Out of scanfrag records in TC (increase MaxNoOfLocalScans)') instead. (Bug #39549) * Creating a unique index on an *Note `NDBCLUSTER': mysql-cluster. table caused a memory leak in the *Note `NDB': mysql-cluster. subscription manager (`SUMA') which could lead to mysqld hanging, due to the fact that the resource shortage was not reported back to the *Note `NDB': mysql-cluster. kernel correctly. (Bug #39518) See also Bug #39450. * Embedded *Note `libmysqld': libmysqld. with *Note `NDB': mysql-cluster. did not drop table events. (Bug #39450) * Unique identifiers in tables having no primary key were not cached. This fix has been observed to increase the efficiency of *Note `INSERT': insert. operations on such tables by as much as 50%. (Bug #39267) * When restarting a data node, an excessively long shutodwn message could cause the node process to crash. (Bug #38580) * After a forced shutdown and initial restart of the cluster, it was possible for SQL nodes to retain `.frm' files corresponding to *Note `NDBCLUSTER': mysql-cluster. tables that had been dropped, and thus to be unaware that these tables no longer existed. In such cases, attempting to re-create the tables using `CREATE TABLE IF NOT EXISTS' could fail with a spurious `Table ... doesn't exist' error. (Bug #37921) * A statement of the form `DELETE FROM TABLE WHERE PRIMARY_KEY=VALUE' or `UPDATE TABLE WHERE PRIMARY_KEY=VALUE' where there was no row whose primary key column had the stated VALUE appeared to succeed, with the server reporting that 1 row had been changed. This issue was only known to affect MySQL Cluster NDB 6.3.11 and later NDB 6.3 versions. (Bug #37153) * *Cluster API*: Passing a value greater than 65535 to `NdbInterpretedCode::add_val()' and `NdbInterpretedCode::sub_val()' caused these methods to have no effect. (Bug #39536) *Changes in MySQL Cluster NDB 6.3.17 (5.1.27-ndb-6.3.17) * *Bugs fixed:* * *Packaging*: Support for the `InnoDB' storage engine was missing from the GPL source releases. An updated GPL source tarball `mysql-5.1.27-ndb-6.3.17-innodb.tar.gz' which includes code for building `InnoDB' can be found on the MySQL FTP site (ftp://ftp.mysql.com/pub/mysql/download/cluster_telco/mysql-5.1.27-ndb-6.3.17/). * `MgmtSrvr::allocNodeId()' left a mutex locked following an `Ambiguity for node if %d' error. (Bug #39158) * An invalid path specification caused `mysql-test-run.pl' to fail. (Bug #39026) * During transactional coordinator takeover (directly after node failure), the LQH finding an operation in the `LOG_COMMIT' state sent an `LQH_TRANS_CONF' signal twice, causing the TC to fail. (Bug #38930) * An invalid memory access caused the management server to crash on Solaris Sparc platforms. (Bug #38628) * A segfault in `Logger::Log' caused *Note `ndbd': mysql-cluster-programs-ndbd. to hang indefinitely. (Bug #38609) * *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. failed to start on older Linux distributions (2.4 kernels) that did not support e-polling. (Bug #38592) * *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. sometimes performed unnecessary network I/O with the client. This in combination with other factors led to long-running threads that were attempting to write to clients that no longer existed. (Bug #38563) * *Note `ndb_restore': mysql-cluster-programs-ndb-restore. failed with a floating point exception due to a division by zero error when trying to restore certain data files. (Bug #38520) * A failed connection to the management server could cause a resource leak in *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. (Bug #38424) * Failure to parse configuration parameters could cause a memory leak in the NDB log parser. (Bug #38380) * Renaming an *Note `NDBCLUSTER': mysql-cluster. table on one SQL node, caused a trigger on this table to be deleted on another SQL node. (Bug #36658) * Attempting to add a `UNIQUE INDEX' twice to an *Note `NDBCLUSTER': mysql-cluster. table, then deleting rows from the table could cause the MySQL Server to crash. (Bug #35599) * *Note `ndb_restore': mysql-cluster-programs-ndb-restore. failed when a single table was specified. (Bug #33801) * `GCP_COMMIT' did not wait for transaction takeover during node failure. This could cause `GCP_SAVE_REQ' to be executed too early. This could also cause (very rarely) replication to skip rows. (Bug #30780) * *Cluster API*: Support for Multi-Range Read index scans using the old API (using, for example, `NdbIndexScanOperation::setBound()' or `NdbIndexScanOperation::end_of_bound()') were dropped in MySQL Cluster NDB 6.2. This functionality is restored in MySQL Cluster NDB 6.3 beginning with 6.3.17, but remains unavailable in MySQL Cluster NDB 6.2. Both MySQL Cluster NDB 6.2 and 6.3 support Multi-Range Read scans through the `NdbRecord' API. (Bug #38791) * *Cluster API*: The `NdbScanOperation::readTuples()' method could be called multiple times without error. (Bug #38717) * *Cluster API*: Certain Multi-Range Read scans involving `IS NULL' and `IS NOT NULL' comparisons failed with an error in the *Note `NDB': mysql-cluster. local query handler. (Bug #38204) * *Cluster API*: Problems with the public headers prevented *Note `NDB': mysql-cluster. applications from being built with warnings turned on. (Bug #38177) * *Cluster API*: Creating an `NdbScanFilter' object using an `NdbScanOperation' object that had not yet had its `readTuples()' method called resulted in a crash when later attempting to use the `NdbScanFilter'. (Bug #37986) * *Cluster API*: Executing an `NdbRecord' interpreted delete created with an `ANYVALUE' option caused the transaction to abort. (Bug #37672) *Changes in MySQL Cluster NDB 6.3.16 (5.1.24-ndb-6.3.16) * *Functionality added or changed:* * Event buffer lag reports are now written to the cluster log. (Bug #37427) * Added the `--no-binlog' option for *Note `ndb_restore': mysql-cluster-programs-ndb-restore. When used, this option prevents information being written to SQL node binary logs from the restoration of a cluster backup. (Bug #30452) *Bugs fixed:* * *Cluster API*: Changing the system time on data nodes could cause MGM API applications to hang and the data nodes to crash. (Bug #35607) * *Cluster API*: Changing the system time on data nodes could cause MGM API applications to hang and the data nodes to crash. (Bug #35607) * Failure of a data node could sometimes cause mysqld to crash. (Bug #37628) * `DELETE ... WHERE UNIQUE_INDEX_COLUMN=VALUE' deleted the wrong row from the table. (Bug #37516) * If subscription was terminated while a node was down, the epoch was not properly acknowledged by that node. (Bug #37442) * `libmysqld' failed to wait for the cluster binlog thread to terminate before exiting. (Bug #37429) * In rare circumstances, a connection followed by a disconnection could give rise to a `stale' connection where the connection still existed but was not seen by the transporter. (Bug #37338) * Queries against *Note `NDBCLUSTER': mysql-cluster. tables were cached only if `autocommit' was in use. (Bug #36692) * *Cluster API*: When some operations succeeded and some failed following a call to `NdbTransaction::execute(Commit, AO_IgnoreOnError)', a race condition could cause spurious occurrences of NDB API Error 4011 (`Internal error'). (Bug #37158) * *Cluster API*: Creating a table on an SQL node, then starting an NDB API application that listened for events from this table, then dropping the table from an SQL node, prevented data node restarts. (Bug #32949, Bug #37279) * *Cluster API*: A buffer overrun in `NdbBlob::setValue()' caused erroneous results on Mac OS X. (Bug #31284) *Changes in MySQL Cluster NDB 6.3.15 (5.1.24-ndb-6.3.15) * *Bugs fixed:* * In certain rare situations, `ndb_size.pl' could fail with the error `Can't use string ("VALUE") as a HASH ref while "strict refs" in use'. (Bug #43022) * Under some circumstances, a failed *Note `CREATE TABLE': create-table. could mean that subsequent *Note `CREATE TABLE': create-table. statements caused node failures. (Bug #37092) * A fail attempt to create an *Note `NDB': mysql-cluster. table could in some cases lead to resource leaks or cluster failures. (Bug #37072) * Attempting to create a native backup of *Note `NDB': mysql-cluster. tables having a large number of `NULL' columns and data could lead to node failures. (Bug #37039) * Checking of API node connections was not efficiently handled. (Bug #36843) * Attempting to delete a nonexistent row from a table containing a *Note `TEXT': blob. or *Note `BLOB': blob. column within a transaction caused the transaction to fail. (Bug #36756) See also Bug #36851. * If the combined total of tables and indexes in the cluster was greater than 4096, issuing `START BACKUP' caused data nodes to fail. (Bug #36044) * Where column values to be compared in a query were of the *Note `VARCHAR': char. or *Note `VARBINARY': binary-varbinary. types, *Note `NDBCLUSTER': mysql-cluster. passed a value padded to the full size of the column, which caused unnecessary data to be sent to the data nodes. This also had the effect of wasting CPU and network bandwidth, and causing condition pushdown to be disabled where it could (and should) otherwise have been applied. (Bug #35393) * When dropping a table failed for any reason (such as when in single user mode) then the corresponding `.ndb' file was still removed. * *Cluster API*: Ordered index scans were not pruned correctly where a partitioning key was specified with an EQ-bound. (Bug #36950) * *Cluster API*: When an insert operation involving *Note `BLOB': blob. data was attempted on a row which already existed, no duplicate key error was correctly reported and the transaction is incorrectly aborted. In some cases, the existing row could also become corrupted. (Bug #36851) See also Bug #26756. * *Cluster API*: `NdbApi.hpp' depended on `ndb_global.h', which was not actually installed, causing the compilation of programs that used `NdbApi.hpp' to fail. (Bug #35853) *Changes in MySQL Cluster NDB 6.3.14 (5.1.24-ndb-6.3.14) * *Bugs fixed:* * `SET GLOBAL ndb_extra_logging' caused *Note `mysqld': mysqld. to crash. (Bug #36547) * A race condition caused by a failure in epoll handling could cause data nodes to fail. (Bug #36537) * Under certain rare circumstances, the failure of the new master node while attempting a node takeover would cause takeover errors to repeat without being resolved. (Bug #36199, Bug #36246, Bug #36247, Bug #36276) * When more than one SQL node connected to the cluster at the same time, creation of the `mysql.ndb_schema' table failed on one of them with an explicit `Table exists' error, which was not necessary. (Bug #35943) * *Note `mysqld': mysqld. failed to start after running *Note `mysql_upgrade': mysql-upgrade. (Bug #35708) * Notification of a cascading master node failures could sometimes not be transmitted correctly (that is, transmission of the `NF_COMPLETEREP' signal could fail), leading to transactions hanging and timing out (*Note `NDB': mysql-cluster. error 4012), scans hanging, and failure of the management server process. (Bug #32645) * If an API node disconnected and then reconnected during Start Phase 8, then the connection could be `blocked'--that is, the `QMGR' kernel block failed to detect that the API node was in fact connected to the cluster, causing issues with the *Note `NDB': mysql-cluster. Subscription Manager (`SUMA'). * *Note `NDB': mysql-cluster. error 1427 (`Api node died, when SUB_START_REQ reached node') was incorrectly classified as a schema error rather than a temporary error. * *Cluster API*: Accesing the debug version of `libndbclient' using `dlopen()' resulted in a segmentation fault. (Bug #35927) * *Cluster API*: Attempting to pass a nonexistent column name to the `equal()' and `setValue()' methods of `NdbOperation' caused NDB API applications to crash. Now the column name is checked, and an error is returned in the event that the column is not found. (Bug #33747) *Changes in MySQL Cluster NDB 6.3.13 (5.1.24-ndb-6.3.13) * *Bugs fixed:* * *Important Change*: *Note `mysqld_safe': mysqld-safe. now traps Signal 13 (`SIGPIPE') so that this signal no longer kills the MySQL server process. (Bug #33984) * Node or system restarts could fail due an unitialized variable in the `DTUP' kernel block. This issue was found in MySQL Cluster NDB 6.3.11. (Bug #35797) * If an error occurred while executing a statement involving a *Note `BLOB': blob. or *Note `TEXT': blob. column of an *Note `NDB': mysql-cluster. table, a memory leak could result. (Bug #35593) * It was not possible to determine the value used for the `--ndb-cluster-connection-pool' option in the *Note `mysql': mysql. client. Now this value is reported as a system status variable. (Bug #35573) * The *Note `ndb_waiter': mysql-cluster-programs-ndb-waiter. utility wrongly calculated timeouts. (Bug #35435) * A *Note `SELECT': select. on a table with a nonindexed, large *Note `VARCHAR': char. column which resulted in condition pushdown on this column could cause *Note `mysqld': mysqld. to crash. (Bug #35413) * *Note `ndb_restore': mysql-cluster-programs-ndb-restore. incorrectly handled some data types when applying log files from backups. (Bug #35343) * In some circumstances, a stopped data node was handled incorrectly, leading to redo log space being exhausted following an initial restart of the node, or an initial or partial restart of the cluster (the wrong CGI might be used in such cases). This could happen, for example, when a node was stopped following the creation of a new table, but before a new LCP could be executed. (Bug #35241) * `SELECT ... LIKE ...' queries yielded incorrect results when used on *Note `NDB': mysql-cluster. tables. As part of this fix, condition pushdown of such queries has been disabled; re-enabling it is expected to be done as part of a later, permanent fix for this issue. (Bug #35185) * *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. reported errors to `STDOUT' rather than to `STDERR'. (Bug #35169) * Nested Multi-Range Read scans failed when the second Multi-Range Read released the first read's unprocessed operations, sometimes leading to an SQL node crash. (Bug #35137) * In some situations, a problem with synchronizing checkpoints between nodes could cause a system restart or a node restart to fail with `Error 630 during restore of TX'. (Bug #34756) * A node failure during an initial node restart followed by another node start could cause the master data node to fail, because it incorrectly gave the node permission to start even if the invalidated node's LCP was still running. (Bug #34702) * When a secondary index on a *Note `DECIMAL': numeric-types. column was used to retrieve data from an *Note `NDB': mysql-cluster. table, no results were returned even if the target table had a matched value in the column that was defined with the secondary index. (Bug #34515) * An *Note `UPDATE': update. on an *Note `NDB': mysql-cluster. table that set a new value for a unique key column could cause subsequent queries to fail. (Bug #34208) * If a data node in one node group was placed in the `not started' state (using `NODE_ID RESTART -n'), it was not possible to stop a data node in a different node group. (Bug #34201) * Numerous *Note `NDBCLUSTER': mysql-cluster. test failures occurred in builds compiled using `icc' on IA64 platforms. (Bug #31239) * If a `START BACKUP' command was issued while *Note `ndb_restore': mysql-cluster-programs-ndb-restore. was running, the backup being restored could be overwritten. (Bug #26498) * *Note `REPLACE': replace. statements did not work correctly with *Note `NDBCLUSTER': mysql-cluster. tables when all columns were not explicitly listed. (Bug #22045) * *Note `CREATE TABLE': create-table. and *Note `ALTER TABLE': alter-table. statements using `ENGINE=NDB' or `ENGINE=NDBCLUSTER' caused *Note `mysqld': mysqld. to fail on Solaris 10 for x86 platforms. (Bug #19911) * *Cluster API*: Closing a scan before it was executed caused the application to segfault. (Bug #36375) * *Cluster API*: Using NDB API applications from older MySQL Cluster versions with `libndbclient' from newer ones caused the cluster to fail. (Bug #36124) * *Cluster API*: Some ordered index scans could return tuples out of order. (Bug #35908) * *Cluster API*: Scans having no bounds set were handled incorrectly. (Bug #35876) * *Cluster API*: `NdbScanFilter::getNdbOperation()', which was inadvertently removed in MySQL Cluster NDB 6.3.11, has been restored. (Bug #35854) *Changes in MySQL Cluster NDB 6.3.10 (5.1.23-ndb-6.3.10) * *Bugs fixed:* * Due to the reduction of the number of local checkpoints from 3 to 2 in MySQL Cluster NDB 6.3.8, a data node using ndbd from MySQL Cluster NDB 6.3.8 or later started using a file system from an earlier version could incorrectly invalidate local checkpoints too early during the startup process, causing the node to fail. (Bug #34596) *Changes in MySQL Cluster NDB 6.3.9 (5.1.23-ndb-6.3.9) * *Bugs fixed:* * Cluster failures could sometimes occur when performing more than three parallel takeovers during node restarts or system restarts. This affected MySQL Cluster NDB 6.3.X releases only. (Bug #34445) * Upgrades of a cluster using while a `DataMemory' setting in excess of 16 GB caused data nodes to fail. (Bug #34378) * Performing many SQL statements on *Note `NDB': mysql-cluster. tables while in `autocommit' mode caused a memory leak in *Note `mysqld': mysqld. (Bug #34275) * In certain rare circumstances, a race condition could occur between an aborted insert and a delete leading a data node crash. (Bug #34260) * Multi-table updates using ordered indexes during handling of node failures could cause other data nodes to fail. (Bug #34216) * When configured with *Note `NDB': mysql-cluster. support, MySQL failed to compile using `gcc' 4.3 on 64bit FreeBSD systems. (Bug #34169) * The failure of a DDL statement could sometimes lead to node failures when attempting to execute subsequent DDL statements. (Bug #34160) * Extremely long *Note `SELECT': select. statements (where the text of the statement was in excess of 50000 characters) against *Note `NDB': mysql-cluster. tables returned empty results. (Bug #34107) * When configured with *Note `NDB': mysql-cluster. support, MySQL failed to compile on 64bit FreeBSD systems. (Bug #34046) * Statements executing multiple inserts performed poorly on *Note `NDB': mysql-cluster. tables having `AUTO_INCREMENT' columns. (Bug #33534) * The *Note `ndb_waiter': mysql-cluster-programs-ndb-waiter. utility polled *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. excessively when obtaining the status of cluster data nodes. (Bug #32025) See also Bug #32023. * Transaction atomicity was sometimes not preserved between reads and inserts under high loads. (Bug #31477) * Having tables with a great many columns could cause Cluster backups to fail. (Bug #30172) * *Cluster Replication*: *Disk Data*: Statements violating unique keys on Disk Data tables (such as attempting to insert `NULL' into a `NOT NULL' column) could cause data nodes to fail. When the statement was executed from the binlog, this could also result in failure of the slave cluster. (Bug #34118) * *Disk Data*: Updating in-memory columns of one or more rows of Disk Data table, followed by deletion of these rows and re-insertion of them, caused data node failures. (Bug #33619) *Changes in MySQL Cluster NDB 6.3.8 (5.1.23-ndb-6.3.8) * *Functionality added or changed:* * *Cluster API*: *Important Change*: Because `NDB_LE_MemoryUsage.page_size_kb' shows memory page sizes in bytes rather than kilobytes, it has been renamed to `page_size_bytes'. The name `page_size_kb' is now deprecated and thus subject to removal in a future release, although it currently remains supported for reasons of backward compatibility. See The `Ndb_logevent_type' Type (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-logevent-type.html), for more information about `NDB_LE_MemoryUsage'. (Bug #30271) * *Note `ndb_restore': mysql-cluster-programs-ndb-restore. now supports basic _attribute promotion_; that is, data from a column of a given type can be restored to a column using a `larger' type. For example, Cluster backup data taken from a *Note `SMALLINT': numeric-types. column can be restored to a *Note `MEDIUMINT': numeric-types, *Note `INT': numeric-types, or *Note `BIGINT': numeric-types. column. For more information, see *Note mysql-cluster-programs-ndb-restore::. * Now only 2 local checkpoints are stored, rather than 3 as in previous MySQL Cluster versions. This lowers disk space requirements and reduces the size and number of redo log files needed. * The *Note `mysqld': mysqld. option `--ndb-batch-size' has been added. This enables control of the size of batches used for running transactions. * Node recovery can now be done in parallel, rather than sequentially, which can result in much faster recovery times. * Persistence of *Note `NDB': mysql-cluster. tables can now be controlled using the session variables `ndb_table_temporary' and `ndb_table_no_logging'. `ndb_table_no_logging' causes *Note `NDB': mysql-cluster. tables not to be checkpointed to disk. `ndb_table_temporary' has the same effect; in addition, when `ndb_table_temporary' is used, no *Note `NDB': mysql-cluster. table schema files are created. * *Note `OPTIMIZE TABLE': optimize-table. can now be interrupted. This can be done, for example, by killing the SQL thread performing the `OPTIMIZE' operation. *Bugs fixed:* * *Disk Data*: *Important Change*: It is no longer possible on 32-bit systems to issue statements appearing to create Disk Data log files or data files greater than 4 GB in size. (Trying to create log files or data files larger than 4 GB on 32-bit systems led to unrecoverable data node failures; such statements now fail with *Note `NDB': mysql-cluster. error 1515.) (Bug #29186) * *Replication*: The code implementing heartbeats did not check for possible errors in some circumstances; this kept the dump thread hanging while waiting for heartbeats loop even though the slave was no longer connected. (Bug #33332) * High numbers of insert operations, delete operations, or both could cause *Note `NDB': mysql-cluster. error 899 (`Rowid already allocated') to occur unnecessarily. (Bug #34033) * A periodic failure to flush the send buffer by the *Note `NDB': mysql-cluster. TCP transporter could cause a unnecessary delay of 10 ms between operations. (Bug #34005) * *Note `DROP TABLE': drop-table. did not free all data memory. This bug was observed in MySQL Cluster NDB 6.3.7 only. (Bug #33802) * A race condition could occur (very rarely) when the release of a GCI was followed by a data node failure. (Bug #33793) * Some tuple scans caused the wrong memory page to be accessed, leading to invalid results. This issue could affect both in-memory and Disk Data tables. (Bug #33739) * A failure to initialize an internal variable led to sporadic crashes during cluster testing. (Bug #33715) * The server failed to reject properly the creation of an *Note `NDB': mysql-cluster. table having an unindexed `AUTO_INCREMENT' column. (Bug #30417) * Issuing an *Note `INSERT ... ON DUPLICATE KEY UPDATE': insert-on-duplicate. concurrently with or following a *Note `TRUNCATE TABLE': truncate-table. statement on an *Note `NDB': mysql-cluster. table failed with *Note `NDB': mysql-cluster. error 4350 `Transaction already aborted'. (Bug #29851) * The Cluster backup process could not detect when there was no more disk space and instead continued to run until killed manually. Now the backup fails with an appropriate error when disk space is exhausted. (Bug #28647) * It was possible in `config.ini' to define cluster nodes having node IDs greater than the maximum permitted value. (Bug #28298) * Under some circumstances, a recovering data node did not use its own data, instead copying data from another node even when this was not required. This in effect bypassed the optimized node recovery protocol and caused recovery times to be unnecessarily long. (Bug #26913) * *Cluster API*: Transactions containing inserts or reads would hang during `NdbTransaction::execute()' calls made from NDB API applications built against a MySQL Cluster version that did not support micro-GCPs accessing a later version that supported micro-GCPs. This issue was observed while upgrading from MySQL Cluster NDB 6.1.23 to MySQL Cluster NDB 6.2.10 when the API application built against the earlier version attempted to access a data node already running the later version, even after disabling micro-GCPs by setting `TimeBetweenEpochs' equal to 0. (Bug #33895) * *Cluster API*: When reading a `BIT(64)' value using `NdbOperation:getValue()', 12 bytes were written to the buffer rather than the expected 8 bytes. (Bug #33750) *Changes in MySQL Cluster NDB 6.3.7 (5.1.23-ndb-6.3.7) * *Functionality added or changed:* * Compressed local checkpoints and backups are now supported, resulting in a space savings of 50% or more over uncompressed LCPs and backups. Compression of these can be enabled in the `config.ini' file using the two new data node configuration parameters `CompressedLCP' and `CompressedBackup', respectively. * *Note `OPTIMIZE TABLE': optimize-table. is now supported for *Note `NDBCLUSTER': mysql-cluster. tables, subject to the following limitations: * Only in-memory tables are supported. `OPTIMIZE' still has no effect on Disk Data tables. * Only variable-length columns are supported. However, you can force columns defined using fixed-length data types to be dynamic using the `ROW_FORMAT' or `COLUMN_FORMAT' option with a *Note `CREATE TABLE': create-table. or *Note `ALTER TABLE': alter-table. statement. Memory reclaimed from an *Note `NDB': mysql-cluster. table using `OPTIMIZE' is generally available to the cluster, and not confined to the table from which it was recovered, unlike the case with memory freed using *Note `DELETE': delete. The performance of `OPTIMIZE' on *Note `NDB': mysql-cluster. tables can be regulated by adjusting the value of the `ndb_optimization_delay' system variable. * It is now possible to cause statements occurring within the same transaction to be run as a batch by setting the session variable `transaction_allow_batching' to `1' or `ON'. *Note*: To use this feature, `autocommit' must be disabled. *Bugs fixed:* * *Partitioning*: When partition pruning on an *Note `NDB': mysql-cluster. table resulted in an ordered index scan spanning only one partition, any descending flag for the scan was wrongly discarded, causing `ORDER BY DESC' to be treated as `ORDER BY ASC', `MAX()' to be handled incorrectly, and similar problems. (Bug #33061) * When all data and SQL nodes in the cluster were shut down abnormally (that is, other than by using `STOP' in the cluster management client), *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. used excessive amounts of CPU. (Bug #33237) * When using micro-GCPs, if a node failed while preparing for a global checkpoint, the master node would use the wrong GCI. (Bug #32922) * Under some conditions, performing an *Note `ALTER TABLE': alter-table. on an *Note `NDBCLUSTER': mysql-cluster. table failed with a `Table is full' error, even when only 25% of `DataMemory' was in use and the result should have been a table using less memory (for example, changing a `VARCHAR(100)' column to `VARCHAR(80)'). (Bug #32670) *Changes in MySQL Cluster NDB 6.3.6 (5.1.22-ndb-6.3.6) * *Functionality added or changed:* * The output of the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client `SHOW' and `STATUS' commands now indicates when the cluster is in single user mode. (Bug #27999) * Unnecessary reads when performing a primary key or unique key update have been reduced, and in some cases, eliminated. (It is almost never necessary to read a record prior to an update, the lone exception to this being when a primary key is updated, since this requires a delete followed by an insert, which must be prepared by reading the record.) Depending on the number of primary key and unique key lookups that are performed per transaction, this can yield a considerable improvement in performance. * Batched operations are now better supported for *Note `DELETE': delete. and *Note `UPDATE': update. (`UPDATE WHERE...' and muliple *Note `DELETE': delete.) * Introduced the `Ndb_execute_count' status variable, which measures the number of round trips made by queries to the *Note `NDB': mysql-cluster. kernel. *Bugs fixed:* * An insert or update with combined range and equality constraints failed when run against an *Note `NDB': mysql-cluster. table with the error `Got unknown error from NDB'. An example of such a statement would be `UPDATE t1 SET b = 5 WHERE a IN (7,8) OR a >= 10;'. (Bug #31874) * An error with an `if' statement in `sql/ha_ndbcluster.cc' could potentially lead to an infinite loop in case of failure when working with `AUTO_INCREMENT' columns in *Note `NDB': mysql-cluster. tables. (Bug #31810) * The *Note `NDB': mysql-cluster. storage engine code was not safe for strict-alias optimization in `gcc' 4.2.1. (Bug #31761) * *Note `ndb_restore': mysql-cluster-programs-ndb-restore. displayed incorrect backup file version information. This meant (for example) that, when attempting to restore a backup made from a MySQL 5.1.22 cluster to a MySQL Cluster NDB 6.3.3 cluster, the restore process failed with the error `Restore program older than backup version. Not supported. Use new restore program.' (Bug #31723) * Following an upgrade, *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. would fail with an ArbitrationError. (Bug #31690) * The *Note `NDB': mysql-cluster. management client command `NODE_ID REPORT MEMORY' provided no output when NODE_ID was the node ID of a management or API node. Now, when this occurs, the management client responds with `Node NODE_ID: is not a data node'. (Bug #29485) * Performing *Note `DELETE': delete. operations after a data node had been shut down could lead to inconsistent data following a restart of the node. (Bug #26450) * `UPDATE IGNORE' could sometimes fail on *Note `NDB': mysql-cluster. tables due to the use of unitialized data when checking for duplicate keys to be ignored. (Bug #25817) *Changes in MySQL Cluster NDB 6.3.5 (5.1.22-ndb-6.3.5) * *Bugs fixed:* * A query against a table with *Note `TEXT': blob. or *Note `BLOB': blob. columns that would return more than a certain amount of data failed with `Got error 4350 'Transaction already aborted' from NDBCLUSTER'. (Bug #31482) This regression was introduced by Bug #29102. *Changes in MySQL Cluster NDB 6.3.4 (5.1.22-ndb-6.3.4) * *Functionality added or changed:* * *Incompatible Change*: The `--ndb_optimized_node_selection' startup option for *Note `mysqld': mysqld. now permits a wider range of values and corresponding behaviors for SQL nodes when selecting a transaction coordinator. You should be aware that the default value and behavior as well as the value type used for this option have changed, and that you may need to update the setting used for this option in your `my.cnf' file prior to upgrading *Note `mysqld': mysqld. See *Note server-system-variables::, for more information. * *Incompatible Change*: The `--ndb_optimized_node_selection' startup option for *Note `mysqld': mysqld. now permits a wider range of values and corresponding behaviors for SQL nodes when selecting a transaction coordinator. You should be aware that the default value and behavior as well as the value type used for this option have changed, and that you may need to update the setting used for this option in your `my.cnf' file prior to upgrading *Note `mysqld': mysqld. See *Note server-system-variables::, for more information. *Bugs fixed:* * It was possible in some cases for a node group to be `lost' due to missed local checkpoints following a system restart. (Bug #31525) * *Note `NDB': mysql-cluster. tables having names containing nonalphanumeric characters (such as ``$'') were not discovered correctly. (Bug #31470) * A node failure during a local checkpoint could lead to a subsequent failure of the cluster during a system restart. (Bug #31257) * A cluster restart could sometimes fail due to an issue with table IDs. (Bug #30975) * Transaction timeouts were not handled well in some circumstances, leading to excessive number of transactions being aborted unnecessarily. (Bug #30379) * In some cases, the cluster managment server logged entries multiple times following a restart of *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. (Bug #29565) * *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. `--help' did not display any information about the `-a' option. (Bug #29509) * An interpreted program of sufficient size and complexity could cause all cluster data nodes to shut down due to buffer overruns. (Bug #29390) * The cluster log was formatted inconsistently and contained extraneous newline characters. (Bug #25064) *Changes in MySQL Cluster NDB 6.3.3 (5.1.22-ndb-6.3.3) * *Functionality added or changed:* * Mapping of *Note `NDB': mysql-cluster. error codes to MySQL storage engine error codes has been improved. (Bug #28423) *Bugs fixed:* * *Partitioning*: *Note `EXPLAIN PARTITIONS': explain. reported partition usage by queries on *Note `NDB': mysql-cluster. tables according to the standard MySQL hash function than the hash function used in the *Note `NDB': mysql-cluster. storage engine. (Bug #29550) * Attempting to restore a backup made on a cluster host using one endian to a machine using the other endian could cause the cluster to fail. (Bug #29674) * The description of the `--print' option provided in the output from *Note `ndb_restore `--help' ': mysql-cluster-programs-ndb-restore. was incorrect. (Bug #27683) * Restoring a backup made on a cluster host using one endian to a machine using the other endian failed for *Note `BLOB': blob. and *Note `DATETIME': datetime. columns. (Bug #27543, Bug #30024) *Changes in MySQL Cluster NDB 6.3.2 (5.1.22-ndb-6.3.2) * *Functionality added or changed:* * Online `ADD COLUMN', `ADD INDEX', and `DROP INDEX' operations can now be performed explicitly for *Note `NDB': mysql-cluster. tables--that is, without copying or locking of the affected tables--using `ALTER ONLINE TABLE'. Indexes can also be created and dropped online using *Note `CREATE INDEX': create-index. and *Note `DROP INDEX': drop-index, respectively, using the `ONLINE' keyword. You can force operations that would otherwise be performed online to be done offline using the `OFFLINE' keyword. Renaming of tables and columns for *Note `NDB': mysql-cluster. and `MyISAM' tables is performed in place without table copying. For more information, see *Note alter-table-online-operations::, *Note create-index::, and *Note drop-index::. * It is now possible to control whether fixed-width or variable-width storage is used for a given column of an *Note `NDB': mysql-cluster. table by means of the `COLUMN_FORMAT' specifier as part of the column's definition in a *Note `CREATE TABLE': create-table. or *Note `ALTER TABLE': alter-table. statement. It is also possible to control whether a given column of an *Note `NDB': mysql-cluster. table is stored in memory or on disk, using the `STORAGE' specifier as part of the column's definition in a *Note `CREATE TABLE': create-table. or *Note `ALTER TABLE': alter-table. statement. For permitted values and other information about `COLUMN_FORMAT' and `STORAGE', see *Note create-table::. * A new cluster management server startup option `--bind-address' makes it possible to restrict management client connections to *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. to a single host and port. For more information, see *Note mysql-cluster-programs-ndb-mgmd::. *Bugs fixed:* * When an *Note `NDB': mysql-cluster. event was left behind but the corresponding table was later recreated and received a new table ID, the event could not be dropped. (Bug #30877) * When creating an `NDB' table with a column that has `COLUMN_FORMAT = DYNAMIC', but the table tiself uses `ROW_FORMAT=FIXED', the table is considered dynamic, but any columns for which the row format is unspecified default to `FIXED'. Now in such cases the server issues the warning `Row format FIXED incompatible with dynamic attribute COLUMN_NAME'. (Bug #30276) * An insufficiently descriptive and potentially misleading Error 4006 (`Connect failure - out of connection objects...') was produced when either of the following two conditions occurred: 1. There were no more transaction records in the transaction coordinator 2. An *Note `NDB': mysql-cluster. object in the NDB API was initialized with insufficient parallelism Separate error messages are now generated for each of these two cases. (Bug #11313) *Changes in MySQL Cluster NDB 6.3.0 (5.1.19-ndb-6.3.0) * *Functionality added or changed:* * Reporting functionality has been significantly enhanced in this release: * A new configuration parameter `BackupReportFrequency' now makes it possible to cause the management client to provide status reports at regular intervals as well as for such reports to be written to the cluster log (depending on cluster event logging levels). * A new `REPORT' command has been added in the cluster management client. `REPORT BackupStatus' enables you to obtain a backup status report at any time during a backup. `REPORT MemoryUsage' reports the current data memory and index memory used by each data node. For more about the `REPORT' command, see *Note mysql-cluster-mgm-client-commands::. * *Note `ndb_restore': mysql-cluster-programs-ndb-restore. now provides running reports of its progress when restoring a backup. In addition, a complete report status report on the backup is written to the cluster log. * A new configuration parameter `ODirect' causes *Note `NDB': mysql-cluster. to attempt using `O_DIRECT' writes for LCP, backups, and redo logs, often lowering CPU usage.  File: manual.info, Node: mysql-cluster-news-6-2-series, Next: mysql-cluster-news-6-1-series, Prev: mysql-cluster-news-6-3-series, Up: mysql-cluster-news-series 17.7.7.4 Changes in the MySQL Cluster NDB 6.2 Series .................................................... This section contains unified change history highlights for all MySQL Cluster releases based on version 6.2 of the *Note `NDBCLUSTER': mysql-cluster. storage engine through MySQL Cluster NDB 6.2.19. Included are all changelog entries in the categories _MySQL Cluster_, _Disk Data_, and _Cluster API_. For an overview of features that were added in MySQL Cluster NDB 6.2, see *Note mysql-cluster-development-5-1-ndb-6-2::. * Changes in MySQL Cluster NDB 6.2.18 (5.1.34-ndb-6.2.18) * Changes in MySQL Cluster NDB 6.2.17 (5.1.32-ndb-6.2.17) * Changes in MySQL Cluster NDB 6.2.16 (5.1.28-ndb-6.2.16) * Changes in MySQL Cluster NDB 6.2.14 (5.1.23-ndb-6.2.14) * Changes in MySQL Cluster NDB 6.2.13 (5.1.23-ndb-6.2.13) * Changes in MySQL Cluster NDB 6.2.12 (5.1.23-ndb-6.2.12) * Changes in MySQL Cluster NDB 6.2.11 (5.1.23-ndb-6.2.11) * Changes in MySQL Cluster NDB 6.2.10 (5.1.23-ndb-6.2.10) * Changes in MySQL Cluster NDB 6.2.9 (5.1.22-ndb-6.2.9) * Changes in MySQL Cluster NDB 6.2.8 (5.1.22-ndb-6.2.8) * Changes in MySQL Cluster NDB 6.2.7 (5.1.22-ndb-6.2.7) * Changes in MySQL Cluster NDB 6.2.6 (5.1.22-ndb-6.2.6) * Changes in MySQL Cluster NDB 6.2.5 (5.1.22-ndb-6.2.5) * Changes in MySQL Cluster NDB 6.2.4 (5.1.19-ndb-6.2.4) * Changes in MySQL Cluster NDB 6.2.3 (5.1.19-ndb-6.2.3) * Changes in MySQL Cluster NDB 6.2.2 (5.1.18-ndb-6.2.2) * Changes in MySQL Cluster NDB 6.2.1 (5.1.18-ndb-6.2.1) * Changes in MySQL Cluster NDB 6.2.0 (5.1.16-ndb-6.2.0) *Changes in MySQL Cluster NDB 6.2.18 (5.1.34-ndb-6.2.18) * *Bugs fixed:* * *Important Change*: *Partitioning*: User-defined partitioning of an *Note `NDBCLUSTER': mysql-cluster. table without any primary key sometimes failed, and could cause *Note `mysqld': mysqld. to crash. Now, if you wish to create an *Note `NDBCLUSTER': mysql-cluster. table with user-defined partitioning, the table must have an explicit primary key, and all columns listed in the partitioning expression must be part of the primary key. The hidden primary key used by the *Note `NDBCLUSTER': mysql-cluster. storage engine is not sufficient for this purpose. However, if the list of columns is empty (that is, the table is defined using `PARTITION BY [LINEAR] KEY()'), then no explicit primary key is required. This change does not effect the partitioning of tables using any storage engine other than *Note `NDBCLUSTER': mysql-cluster. (Bug #40709) * An internal NDB API buffer was not properly initialized. (Bug #44977) * When a data node had written its GCI marker to the first page of a megabyte, and that node was later killed during restart after having processed that page (marker) but before completing a LCP, the data node could fail with file system errors. (Bug #44952) See also Bug #42564, Bug #44291. * Inspection of the code revealed that several assignment operators (`=') were used in place of comparison operators (`==') in `DbdihMain.cpp'. (Bug #44567) See also Bug #44570. * It was possible for NDB API applications to insert corrupt data into the database, which could subquently lead to data node crashes. Now, stricter checking is enforced on input data for inserts and updates. (Bug #44132) * `TransactionDeadlockDetectionTimeout' values less than 100 were treated as 100. This could cause scans to time out unexpectedly. (Bug #44099) * The file `ndberror.c' contained a C++-style comment, which caused builds to fail with some C compilers. (Bug #44036) * A race condition could occur when a data node failed to restart just before being included in the next global checkpoint. This could cause other data nodes to fail. (Bug #43888) * When trying to use a data node with an older version of the management server, the data node crashed on startup. (Bug #43699) * Using indexes containing variable-sized columns could lead to internal errors when the indexes were being built. (Bug #43226) * In some cases, data node restarts during a system restart could fail due to insufficient redo log space. (Bug #43156) * Some queries using combinations of logical and comparison operators on an indexed column in the `WHERE' clause could fail with the error `Got error 4541 'IndexBound has no bound information' from NDBCLUSTER'. (Bug #42857) * *Note `ndb_restore `--print_data'': mysql-cluster-programs-ndb-restore. did not handle *Note `DECIMAL': numeric-types. columns correctly. (Bug #37171) * The output of *Note `ndbd `--help'': mysql-cluster-programs-ndbd. did not provide clear information about the program's `--initial' and `--initial-start' options. (Bug #28905) * It was theoretically possible for the value of a nonexistent column to be read as `NULL', rather than causing an error. (Bug #27843) * When aborting an operation involving both an insert and a delete, the insert and delete were aborted separately. This was because the transaction coordinator did not know that the operations affected on same row, and, in the case of a committed-read (tuple or index) scan, the abort of the insert was performed first, then the row was examined after the insert was aborted but before the delete was aborted. In some cases, this would leave the row in a inconsistent state. This could occur when a local checkpoint was performed during a backup. This issue did not affect primary ley operations or scans that used locks (these are serialized). After this fix, for ordered indexes, all operations that follow the operation to be aborted are now also aborted. * *Disk Data*: *Partitioning*: An *Note `NDB': mysql-cluster. table created with a very large value for the `MAX_ROWS' option could--if this table was dropped and a new table with fewer partitions, but having the same table ID, was created--cause *Note `ndbd': mysql-cluster-programs-ndbd. to crash when performing a system restart. This was because the server attempted to examine each partition whether or not it actually existed. (Bug #45154) See also Bug #58638. * *Disk Data*: During a checkpoint, restore points are created for both the on-disk and in-memory parts of a Disk Data table. Under certain rare conditions, the in-memory restore point could include or exclude a row that should have been in the snapshot. This would later lead to a crash during or following recovery. (Bug #41915) See also Bug #47832. * *Disk Data*: When a log file group had an undo log file whose size was too small, restarting data nodes failed with `Read underflow' errors. As a result of this fix, the minimum permitted `INTIAL_SIZE' for an undo log file is now `1M' (1 megabyte). (Bug #29574) * *Disk Data*: This fix supercedes and improves on an earlier fix made for this bug in MySQL 5.1.18. (Bug #24521) * *Cluster API*: If the largest offset of a `RecordSpecification' used for an `NdbRecord' object was for the `NULL' bits (and thus not a column), this offset was not taken into account when calculating the size used for the `RecordSpecification'. This meant that the space for the `NULL' bits could be overwritten by key or other information. (Bug #43891) * *Cluster API*: The default `NdbRecord' structures created by `NdbDictionary' could have overlapping null bits and data fields. (Bug #43590) * *Cluster API*: When performing insert or write operations, `NdbRecord' permits key columns to be specified in both the key record and in the attribute record. Only one key column value for each key column should be sent to the NDB kernel, but this was not guaranteed. This is now ensured as follows: For insert and write operations, key column values are taken from the key record; for scan takeover update operations, key column values are taken from the attribute record. (Bug #42238) * *Cluster API*: Ordered index scans using `NdbRecord' formerly expressed a `BoundEQ' range as separate lower and upper bounds, resulting in 2 copies of the column values being sent to the NDB kernel. Now, when a range is specified by `NdbScanOperation::setBound()', the passed pointers, key lengths, and inclusive bits are compared, and only one copy of the equal key columns is sent to the kernel. This makes such operations more efficient, as half the amount of `KeyInfo' is now sent for a `BoundEQ' range as before. (Bug #38793) *Changes in MySQL Cluster NDB 6.2.17 (5.1.32-ndb-6.2.17) * *Functionality added or changed:* * *Important Change*: Formerly, when the management server failed to create a transporter for a data node connection, `net_write_timeout' seconds elapsed before the data node was actually permitted to disconnect. Now in such cases the disconnection occurs immediately. (Bug #41965) See also Bug #41713. * *Disk Data*: It is now possible to specify default locations for Disk Data data files and undo log files, either together or separately, using the data node configuration parameters `FileSystemPathDD', `FileSystemPathDataFiles', and `FileSystemPathUndoFiles'. For information about these configuration parameters, see `Disk Data file system parameters'. It is also now possible to specify a log file group, tablespace, or both, that is created when the cluster is started, using the `InitialLogFileGroup' and `InitialTablespace' data node configuration parameters. For information about these configuration parameters, see `Disk Data object creation parameters'. *Bugs fixed:* * *Performance*: Updates of the `SYSTAB_0' system table to obtain a unique identifier did not use transaction hints for tables having no primary key. In such cases the NDB kernel used a cache size of 1. This meant that each insert into a table not having a primary key required an update of the corresponding `SYSTAB_0' entry, creating a potential performance bottleneck. With this fix, inserts on `NDB' tables without primary keys can be under some conditions be performed up to 100% faster than previously. (Bug #39268) * *Packaging*: Packages for MySQL Cluster were missing the `libndbclient.so' and `libndbclient.a' files. (Bug #42278) * *Partitioning*: Executing `ALTER TABLE ... REORGANIZE PARTITION' on an *Note `NDBCLUSTER': mysql-cluster. table having only one partition caused *Note `mysqld': mysqld. to crash. (Bug #41945) See also Bug #40389. * *Cluster API*: Failed operations on *Note `BLOB': blob. and *Note `TEXT': blob. columns were not always reported correctly to the originating SQL node. Such errors were sometimes reported as being due to timeouts, when the actual problem was a transporter overload due to insufficient buffer space. (Bug #39867, Bug #39879) * *Cluster API*: Failed operations on *Note `BLOB': blob. and *Note `TEXT': blob. columns were not always reported correctly to the originating SQL node. Such errors were sometimes reported as being due to timeouts, when the actual problem was a transporter overload due to insufficient buffer space. (Bug #39867, Bug #39879) * Backup IDs greater than 2^31 were not handled correctly, causing negative values to be used in backup directory names and printouts. (Bug #43042) * When using *Note `ndbmtd': mysql-cluster-programs-ndbmtd, NDB kernel threads could hang while trying to start the data nodes with `LockPagesInMainMemory' set to 1. (Bug #43021) * When using multiple management servers and starting several API nodes (possibly including one or more SQL nodes) whose connectstrings listed the management servers in different order, it was possible for 2 API nodes to be assigned the same node ID. When this happened it was possible for an API node not to get fully connected, consequently producing a number of errors whose cause was not easily recognizable. (Bug #42973) * *Note `ndb_error_reporter': mysql-cluster-programs-ndb-error-reporter. worked correctly only with GNU `tar'. (With other versions of `tar', it produced empty archives.) (Bug #42753) * Triggers on *Note `NDBCLUSTER': mysql-cluster. tables caused such tables to become locked. (Bug #42751) See also Bug #16229, Bug #18135. * When performing more than 32 index or tuple scans on a single fragment, the scans could be left hanging. This caused unnecessary timeouts, and in addition could possibly lead to a hang of an LCP. (Bug #42559) * A data node failure that occurred between calls to `NdbIndexScanOperation::readTuples(SF_OrderBy)' and `NdbTransaction::execute()' was not correctly handled; a subsequent call to `nextResult()' caused a null pointer to be deferenced, leading to a segfault in *Note `mysqld': mysqld. (Bug #42545) * Issuing `SHOW GLOBAL STATUS LIKE 'NDB%'' before *Note `mysqld': mysqld. had connected to the cluster caused a segmentation fault. (Bug #42458) * Data node failures that occurred before all data nodes had connected to the cluster were not handled correctly, leading to additional data node failures. (Bug #42422) * When a cluster backup failed with Error 1304 (Node NODE_ID1: Backup request from NODE_ID2 failed to start), no clear reason for the failure was provided. As part of this fix, MySQL Cluster now retries backups in the event of sequence errors. (Bug #42354) See also Bug #22698. * Issuing *Note `SHOW ENGINE NDBCLUSTER STATUS': show-engine. on an SQL node before the management server had connected to the cluster caused *Note `mysqld': mysqld. to crash. (Bug #42264) * A maximum of 11 `TUP' scans were permitted in parallel. (Bug #42084) * Trying to execute an *Note `ALTER ONLINE TABLE ... ADD COLUMN': alter-table. statement while inserting rows into the table caused *Note `mysqld': mysqld. to crash. (Bug #41905) * If the master node failed during a global checkpoint, it was possible in some circumstances for the new master to use an incorrect value for the global checkpoint index. This could occur only when the cluster used more than one node group. (Bug #41469) * API nodes disconnected too agressively from cluster when data nodes were being restarted. This could sometimes lead to the API node being unable to access the cluster at all during a rolling restart. (Bug #41462) * An abort path in the `DBLQH' kernel block failed to release a commit acknowledgment marker. This meant that, during node failure handling, the local query handler could be added multiple times to the marker record which could lead to additional node failures due an array overflow. (Bug #41296) * During node failure handling (of a data node other than the master), there was a chance that the master was waiting for a `GCP_NODEFINISHED' signal from the failed node after having received it from all other data nodes. If this occurred while the failed node had a transaction that was still being committed in the current epoch, the master node could crash in the `DBTC' kernel block when discovering that a transaction actually belonged to an epoch which was already completed. (Bug #41295) * If a transaction was aborted during the handling of a data node failure, this could lead to the later handling of an API node failure not being completed. (Bug #41214) * Given a MySQL Cluster containing no data (that is, whose data nodes had all been started using `--initial', and into which no data had yet been imported) and having an empty backup directory, executing `START BACKUP' with a user-specified backup ID caused the data nodes to crash. (Bug #41031) * Issuing `EXIT' in the management client sometimes caused the client to hang. (Bug #40922) * Redo log creation was very slow on some platforms, causing MySQL Cluster to start more slowly than necessary with some combinations of hardware and operating system. This was due to all write operations being synchronized to disk while creating a redo log file. Now this synchronization occurs only after the redo log has been created. (Bug #40734) * Transaction failures took longer to handle than was necessary. When a data node acting as transaction coordinator (TC) failed, the surviving data nodes did not inform the API node initiating the transaction of this until the failure had been processed by all protocols. However, the API node needed only to know about failure handling by the transaction protocol--that is, it needed to be informed only about the TC takeover process. Now, API nodes (including MySQL servers acting as cluster SQL nodes) are informed as soon as the TC takeover is complete, so that it can carry on operating more quickly. (Bug #40697) * It was theoretically possible for stale data to be read from *Note `NDBCLUSTER': mysql-cluster. tables when the transaction isolation level was set to `ReadCommitted'. (Bug #40543) * In some cases, *Note `NDB': mysql-cluster. did not check correctly whether tables had changed before trying to use the query cache. This could result in a crash of the debug MySQL server. (Bug #40464) * Restoring a MySQL Cluster from a dump made using *Note `mysqldump': mysqldump. failed due to a spurious error: `Can't execute the given command because you have active locked tables or an active transaction'. (Bug #40346) * `O_DIRECT' was incorrectly disabled when making MySQL Cluster backups. (Bug #40205) * Events logged after setting `ALL CLUSTERLOG STATISTICS=15' in the management client did not always include the node ID of the reporting node. (Bug #39839) * Start phase reporting was inconsistent between the management client and the cluster log. (Bug #39667) * The MySQL Query Cache did not function correctly with *Note `NDBCLUSTER': mysql-cluster. tables containing *Note `TEXT': blob. columns. (Bug #39295) * A segfault in `Logger::Log' caused *Note `ndbd': mysql-cluster-programs-ndbd. to hang indefinitely. This fix improves on an earlier one for this issue, first made in MySQL Cluster NDB 6.2.16 and MySQL Cluster NDB 6.3.17. (Bug #39180) See also Bug #38609. * Memory leaks could occur in handling of strings used for storing cluster metadata and providing output to users. (Bug #38662) * In the event that a MySQL Cluster backup failed due to file permissions issues, conflicting reports were issued in the management client. (Bug #34526) * A duplicate key or other error raised when inserting into an *Note `NDBCLUSTER': mysql-cluster. table caused the current transaction to abort, after which any SQL statement other than a *Note `ROLLBACK': commit. failed. With this fix, the *Note `NDBCLUSTER': mysql-cluster. storage engine now performs an implicit rollback when a transaction is aborted in this way; it is no longer necessary to issue an explicit *Note `ROLLBACK': commit. statement, and the next statement that is issued automatically begins a new transaction. *Note*: It remains necessary in such cases to retry the complete transaction, regardless of which statement caused it to be aborted. (Bug #32656) See also Bug #47654. * Error messages for *Note `NDBCLUSTER': mysql-cluster. error codes 1224 and 1227 were missing. (Bug #28496) * *Disk Data*: It was not possible to add an in-memory column online to a table that used a table-level or column-level `STORAGE DISK' option. The same issue prevented `ALTER ONLINE TABLE ... REORGANIZE PARTITION' from working on Disk Data tables. (Bug #42549) * *Disk Data*: Issuing concurrent *Note `CREATE TABLESPACE': create-tablespace, *Note `ALTER TABLESPACE': alter-tablespace, *Note `CREATE LOGFILE GROUP': create-logfile-group, or *Note `ALTER LOGFILE GROUP': alter-logfile-group. statements on separate SQL nodes caused a resource leak that led to data node crashes when these statements were used again later. (Bug #40921) * *Disk Data*: Disk-based variable-length columns were not always handled like their memory-based equivalents, which could potentially lead to a crash of cluster data nodes. (Bug #39645) * *Disk Data*: Creating a Disk Data tablespace with a very large extent size caused the data nodes to fail. The issue was observed when using extent sizes of 100 MB and larger. (Bug #39096) * *Disk Data*: Creation of a tablespace data file whose size was greater than 4 GB failed silently on 32-bit platforms. (Bug #37116) See also Bug #29186. * *Disk Data*: `O_SYNC' was incorrectly disabled on platforms that do not support `O_DIRECT'. This issue was noted on Solaris but could have affected other platforms not having `O_DIRECT' capability. (Bug #34638) * *Disk Data*: Trying to execute a *Note `CREATE LOGFILE GROUP': create-logfile-group. statement using a value greater than `150M' for `UNDO_BUFFER_SIZE' caused data nodes to crash. As a result of this fix, the upper limit for `UNDO_BUFFER_SIZE' is now `600M'; attempting to set a higher value now fails gracefully with an error. (Bug #34102) See also Bug #36702. * *Disk Data*: When attempting to create a tablespace that already existed, the error message returned was `Table or index with given name already exists'. (Bug #32662) * *Disk Data*: Using a path or filename longer than 128 characters for Disk Data undo log files and tablespace data files caused a number of issues, including failures of *Note `CREATE LOGFILE GROUP': create-logfile-group, *Note `ALTER LOGFILE GROUP': alter-logfile-group, *Note `CREATE TABLESPACE': create-tablespace, and *Note `ALTER TABLESPACE': alter-tablespace. statements, as well as crashes of management nodes and data nodes. With this fix, the maximum length for path and file names used for Disk Data undo log files and tablespace data files is now the same as the maximum for the operating system. (Bug #31769, Bug #31770, Bug #31772) * *Disk Data*: Starting a cluster under load such that Disk Data tables used most of the undo buffer could cause data node failures. The fix for this bug also corrected an issue in the `LGMAN' kernel block where the amount of free space left in the undo buffer was miscalculated, causing buffer overruns. This could cause records in the buffer to be overwritten, leading to problems when restarting data nodes. (Bug #28077) * *Disk Data*: Attempting to perform a system restart of the cluster where there existed a logfile group without and undo log files caused the data nodes to crash. *Note*: While issuing a *Note `CREATE LOGFILE GROUP': create-logfile-group. statement without an `ADD UNDOFILE' option fails with an error in the MySQL server, this situation could arise if an SQL node failed during the execution of a valid *Note `CREATE LOGFILE GROUP': create-logfile-group. statement; it is also possible to create a logfile group without any undo log files using the NDB API. (Bug #17614) * *Cluster API*: Some error messages from *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. contained newline (`\n') characters. This could break the MGM API protocol, which uses the newline as a line separator. (Bug #43104) * *Cluster API*: When using an ordered index scan without putting all key columns in the read mask, this invalid use of the NDB API went undetected, which resulted in the use of uninitialized memory. (Bug #42591) * *Cluster API*: The MGM API reset error codes on management server handles before checking them. This meant that calling an MGM API function with a null handle caused applications to crash. (Bug #40455) * *Cluster API*: It was not always possible to access parent objects directly from `NdbBlob', `NdbOperation', and `NdbScanOperation' objects. To alleviate this problem, a new `getNdbOperation()' method has been added to `NdbBlob' and new getNdbTransaction() methods have been added to `NdbOperation' and `NdbScanOperation'. In addition, a const variant of `NdbOperation::getErrorLine()' is now also available. (Bug #40242) * *Cluster API*: `NdbScanOperation::getBlobHandle()' failed when used with incorrect column names or numbers. (Bug #40241) * *Cluster API*: The NDB API example programs included in MySQL Cluster source distributions failed to compile. (Bug #37491) See also Bug #40238. * *Cluster API*: `mgmapi.h' contained constructs which only worked in C++, but not in C. (Bug #27004) *Changes in MySQL Cluster NDB 6.2.16 (5.1.28-ndb-6.2.16) * *Functionality added or changed:* * It is no longer a requirement for database autodiscovery that an SQL node already be connected to the cluster at the time that a database is created on another SQL node. It is no longer necessary to issue *Note `CREATE DATABASE': create-database. (or *Note `CREATE SCHEMA': create-database.) statements on an SQL node joining the cluster after a database is created for the new SQL node to see the database and any `NDCLUSTER' tables that it contains. (Bug #39612) *Bugs fixed:* * Heavy DDL usage caused the *Note `mysqld': mysqld. processes to hang due to a timeout error (*Note `NDB': mysql-cluster. error code 266). (Bug #39885) * Executing *Note `EXPLAIN SELECT': explain. on an *Note `NDBCLUSTER': mysql-cluster. table could cause *Note `mysqld': mysqld. to crash. (Bug #39872) * Starting the MySQL Server with the `--ndbcluster' option plus an invalid command-line option (for example, using *Note `mysqld': mysqld. `--ndbcluster --foobar') caused it to hang while shutting down the binlog thread. (Bug #39635) * Dropping and then re-creating a database on one SQL node caused other SQL nodes to hang. (Bug #39613) * Setting a low value of `MaxNoOfLocalScans' (< 100) and performing a large number of (certain) scans could cause the Transaction Coordinator to run out of scan fragment records, and then crash. Now when this resource is exhausted, the cluster returns Error 291 (`Out of scanfrag records in TC (increase MaxNoOfLocalScans)') instead. (Bug #39549) * Creating a unique index on an *Note `NDBCLUSTER': mysql-cluster. table caused a memory leak in the *Note `NDB': mysql-cluster. subscription manager (`SUMA') which could lead to mysqld hanging, due to the fact that the resource shortage was not reported back to the *Note `NDB': mysql-cluster. kernel correctly. (Bug #39518) See also Bug #39450. * Unique identifiers in tables having no primary key were not cached. This fix has been observed to increase the efficiency of *Note `INSERT': insert. operations on such tables by as much as 50%. (Bug #39267) * `MgmtSrvr::allocNodeId()' left a mutex locked following an `Ambiguity for node if %d' error. (Bug #39158) * An invalid path specification caused `mysql-test-run.pl' to fail. (Bug #39026) * During transactional coordinator takeover (directly after node failure), the LQH finding an operation in the `LOG_COMMIT' state sent an `LQH_TRANS_CONF' signal twice, causing the TC to fail. (Bug #38930) * An invalid memory access caused the management server to crash on Solaris Sparc platforms. (Bug #38628) * A segfault in `Logger::Log' caused *Note `ndbd': mysql-cluster-programs-ndbd. to hang indefinitely. (Bug #38609) * *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. failed to start on older Linux distributions (2.4 kernels) that did not support e-polling. (Bug #38592) * When restarting a data node, an excessively long shutodwn message could cause the node process to crash. (Bug #38580) * *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. sometimes performed unnecessary network I/O with the client. This in combination with other factors led to long-running threads that were attempting to write to clients that no longer existed. (Bug #38563) * *Note `ndb_restore': mysql-cluster-programs-ndb-restore. failed with a floating point exception due to a division by zero error when trying to restore certain data files. (Bug #38520) * A failed connection to the management server could cause a resource leak in *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. (Bug #38424) * Failure to parse configuration parameters could cause a memory leak in the NDB log parser. (Bug #38380) * After a forced shutdown and initial restart of the cluster, it was possible for SQL nodes to retain `.frm' files corresponding to *Note `NDBCLUSTER': mysql-cluster. tables that had been dropped, and thus to be unaware that these tables no longer existed. In such cases, attempting to re-create the tables using `CREATE TABLE IF NOT EXISTS' could fail with a spurious `Table ... doesn't exist' error. (Bug #37921) * Renaming an *Note `NDBCLUSTER': mysql-cluster. table on one SQL node, caused a trigger on this table to be deleted on another SQL node. (Bug #36658) * Attempting to add a `UNIQUE INDEX' twice to an *Note `NDBCLUSTER': mysql-cluster. table, then deleting rows from the table could cause the MySQL Server to crash. (Bug #35599) * *Note `ndb_restore': mysql-cluster-programs-ndb-restore. failed when a single table was specified. (Bug #33801) * `GCP_COMMIT' did not wait for transaction takeover during node failure. This could cause `GCP_SAVE_REQ' to be executed too early. This could also cause (very rarely) replication to skip rows. (Bug #30780) * *Cluster API*: Passing a value greater than 65535 to `NdbInterpretedCode::add_val()' and `NdbInterpretedCode::sub_val()' caused these methods to have no effect. (Bug #39536) * *Cluster API*: The `NdbScanOperation::readTuples()' method could be called multiple times without error. (Bug #38717) * *Cluster API*: Certain Multi-Range Read scans involving `IS NULL' and `IS NOT NULL' comparisons failed with an error in the *Note `NDB': mysql-cluster. local query handler. (Bug #38204) * *Cluster API*: Problems with the public headers prevented *Note `NDB': mysql-cluster. applications from being built with warnings turned on. (Bug #38177) * *Cluster API*: Creating an `NdbScanFilter' object using an `NdbScanOperation' object that had not yet had its `readTuples()' method called resulted in a crash when later attempting to use the `NdbScanFilter'. (Bug #37986) * *Cluster API*: Executing an `NdbRecord' interpreted delete created with an `ANYVALUE' option caused the transaction to abort. (Bug #37672) * *Cluster API*: Accesing the debug version of `libndbclient' using `dlopen()' resulted in a segmentation fault. (Bug #35927) *Changes in MySQL Cluster NDB 6.2.14 (5.1.23-ndb-6.2.14) * *Functionality added or changed:* * Added the `MaxBufferedEpochs' data node configuration parameter, which controls the maximum number of unprocessed epochs by which a subscribing node can lag. Subscribers which exceed this number are disconnected and forced to reconnect. See *Note mysql-cluster-ndbd-definition::, for more information. *Bugs fixed:* * *Incompatible Change*: The *Note `UPDATE': update. statement permitted `NULL' to be assigned to `NOT NULL' columns (the implicit default value for the column data type was assigned). This was changed so that on error occurs. This change was reverted, because the original report was determined not to be a bug: Assigning `NULL' to a `NOT NULL' column in an *Note `UPDATE': update. statement should produce an error only in strict SQL mode and set the column to the implicit default with a warning otherwise, which was the original behavior. See *Note data-type-defaults::, and Bug#39265. (Bug #33699) * *Cluster API*: Closing a scan before it was executed caused the application to segfault. (Bug #36375) * *Cluster API*: Using NDB API applications from older MySQL Cluster versions with `libndbclient' from newer ones caused the cluster to fail. (Bug #36124) * *Cluster API*: Scans having no bounds set were handled incorrectly. (Bug #35876) *Changes in MySQL Cluster NDB 6.2.13 (5.1.23-ndb-6.2.13) * *Bugs fixed:* * A node failure during an initial node restart followed by another node start could cause the master data node to fail, because it incorrectly gave the node permission to start even if the invalidated node's LCP was still running. (Bug #34702) *Changes in MySQL Cluster NDB 6.2.12 (5.1.23-ndb-6.2.12) * *Bugs fixed:* * Upgrades of a cluster using while a `DataMemory' setting in excess of 16 GB caused data nodes to fail. (Bug #34378) * Performing many SQL statements on *Note `NDB': mysql-cluster. tables while in `autocommit' mode caused a memory leak in *Note `mysqld': mysqld. (Bug #34275) * In certain rare circumstances, a race condition could occur between an aborted insert and a delete leading a data node crash. (Bug #34260) * Multi-table updates using ordered indexes during handling of node failures could cause other data nodes to fail. (Bug #34216) * When configured with *Note `NDB': mysql-cluster. support, MySQL failed to compile using `gcc' 4.3 on 64bit FreeBSD systems. (Bug #34169) * The failure of a DDL statement could sometimes lead to node failures when attempting to execute subsequent DDL statements. (Bug #34160) * Extremely long *Note `SELECT': select. statements (where the text of the statement was in excess of 50000 characters) against *Note `NDB': mysql-cluster. tables returned empty results. (Bug #34107) * Statements executing multiple inserts performed poorly on *Note `NDB': mysql-cluster. tables having `AUTO_INCREMENT' columns. (Bug #33534) * The *Note `ndb_waiter': mysql-cluster-programs-ndb-waiter. utility polled *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. excessively when obtaining the status of cluster data nodes. (Bug #32025) See also Bug #32023. * Transaction atomicity was sometimes not preserved between reads and inserts under high loads. (Bug #31477) * Having tables with a great many columns could cause Cluster backups to fail. (Bug #30172) * *Cluster Replication*: *Disk Data*: Statements violating unique keys on Disk Data tables (such as attempting to insert `NULL' into a `NOT NULL' column) could cause data nodes to fail. When the statement was executed from the binlog, this could also result in failure of the slave cluster. (Bug #34118) * *Disk Data*: Updating in-memory columns of one or more rows of Disk Data table, followed by deletion of these rows and re-insertion of them, caused data node failures. (Bug #33619) *Changes in MySQL Cluster NDB 6.2.11 (5.1.23-ndb-6.2.11) * *Functionality added or changed:* * *Cluster API*: *Important Change*: Because `NDB_LE_MemoryUsage.page_size_kb' shows memory page sizes in bytes rather than kilobytes, it has been renamed to `page_size_bytes'. The name `page_size_kb' is now deprecated and thus subject to removal in a future release, although it currently remains supported for reasons of backward compatibility. See The `Ndb_logevent_type' Type (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-logevent-type.html), for more information about `NDB_LE_MemoryUsage'. (Bug #30271) *Bugs fixed:* * High numbers of insert operations, delete operations, or both could cause *Note `NDB': mysql-cluster. error 899 (`Rowid already allocated') to occur unnecessarily. (Bug #34033) * A periodic failure to flush the send buffer by the *Note `NDB': mysql-cluster. TCP transporter could cause a unnecessary delay of 10 ms between operations. (Bug #34005) * A race condition could occur (very rarely) when the release of a GCI was followed by a data node failure. (Bug #33793) * Some tuple scans caused the wrong memory page to be accessed, leading to invalid results. This issue could affect both in-memory and Disk Data tables. (Bug #33739) * The server failed to reject properly the creation of an *Note `NDB': mysql-cluster. table having an unindexed `AUTO_INCREMENT' column. (Bug #30417) * Issuing an *Note `INSERT ... ON DUPLICATE KEY UPDATE': insert-on-duplicate. concurrently with or following a *Note `TRUNCATE TABLE': truncate-table. statement on an *Note `NDB': mysql-cluster. table failed with *Note `NDB': mysql-cluster. error 4350 `Transaction already aborted'. (Bug #29851) * The Cluster backup process could not detect when there was no more disk space and instead continued to run until killed manually. Now the backup fails with an appropriate error when disk space is exhausted. (Bug #28647) * It was possible in `config.ini' to define cluster nodes having node IDs greater than the maximum permitted value. (Bug #28298) * *Cluster API*: Transactions containing inserts or reads would hang during `NdbTransaction::execute()' calls made from NDB API applications built against a MySQL Cluster version that did not support micro-GCPs accessing a later version that supported micro-GCPs. This issue was observed while upgrading from MySQL Cluster NDB 6.1.23 to MySQL Cluster NDB 6.2.10 when the API application built against the earlier version attempted to access a data node already running the later version, even after disabling micro-GCPs by setting `TimeBetweenEpochs' equal to 0. (Bug #33895) * *Cluster API*: When reading a `BIT(64)' value using `NdbOperation:getValue()', 12 bytes were written to the buffer rather than the expected 8 bytes. (Bug #33750) *Changes in MySQL Cluster NDB 6.2.10 (5.1.23-ndb-6.2.10) * *Bugs fixed:* * *Partitioning*: When partition pruning on an *Note `NDB': mysql-cluster. table resulted in an ordered index scan spanning only one partition, any descending flag for the scan was wrongly discarded, causing `ORDER BY DESC' to be treated as `ORDER BY ASC', `MAX()' to be handled incorrectly, and similar problems. (Bug #33061) * When all data and SQL nodes in the cluster were shut down abnormally (that is, other than by using `STOP' in the cluster management client), *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. used excessive amounts of CPU. (Bug #33237) * When using micro-GCPs, if a node failed while preparing for a global checkpoint, the master node would use the wrong GCI. (Bug #32922) * Under some conditions, performing an *Note `ALTER TABLE': alter-table. on an *Note `NDBCLUSTER': mysql-cluster. table failed with a `Table is full' error, even when only 25% of `DataMemory' was in use and the result should have been a table using less memory (for example, changing a `VARCHAR(100)' column to `VARCHAR(80)'). (Bug #32670) *Changes in MySQL Cluster NDB 6.2.9 (5.1.22-ndb-6.2.9) * *Functionality added or changed:* * Added the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client command `DUMP 8011', which dumps all subscribers to the cluster log. See `DUMP 8011' (http://dev.mysql.com/doc/ndbapi/en/ndb-internals-dump-command-8011.html), for more information. *Bugs fixed:* * A local checkpoint could sometimes be started before the previous LCP was restorable from a global checkpoint. (Bug #32519) * High numbers of API nodes on a slow or congested network could cause connection negotiation to time out prematurely, leading to the following issues: * Excessive retries * Excessive CPU usage * Partially connected API nodes (Bug #32359) * The failure of a master node could lead to subsequent failures in local checkpointing. (Bug #32160) * Adding a new *Note `TINYTEXT': blob. column to an *Note `NDB': mysql-cluster. table which used `COLUMN_FORMAT = DYNAMIC', and when binary logging was enabled, caused all cluster *Note `mysqld': mysqld. processes to crash. (Bug #30213) * After adding a new column of one of the *Note `TEXT': blob. or *Note `BLOB': blob. types to an *Note `NDB': mysql-cluster. table which used `COLUMN_FORMAT = DYNAMIC', it was no longer possible to access or drop the table using SQL. (Bug #30205) * A restart of the cluster failed when more than 1 REDO phase was in use. (Bug #22696) *Changes in MySQL Cluster NDB 6.2.8 (5.1.22-ndb-6.2.8) * *Functionality added or changed:* * The output of the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client `SHOW' and `STATUS' commands now indicates when the cluster is in single user mode. (Bug #27999) *Bugs fixed:* * In a cluster running in diskless mode and with arbitration disabled, the failure of a data node during an insert operation caused other data node to fail. (Bug #31980) * An insert or update with combined range and equality constraints failed when run against an *Note `NDB': mysql-cluster. table with the error `Got unknown error from NDB'. An example of such a statement would be `UPDATE t1 SET b = 5 WHERE a IN (7,8) OR a >= 10;'. (Bug #31874) * An error with an `if' statement in `sql/ha_ndbcluster.cc' could potentially lead to an infinite loop in case of failure when working with `AUTO_INCREMENT' columns in *Note `NDB': mysql-cluster. tables. (Bug #31810) * The *Note `NDB': mysql-cluster. storage engine code was not safe for strict-alias optimization in `gcc' 4.2.1. (Bug #31761) * Following an upgrade, *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. would fail with an ArbitrationError. (Bug #31690) * The *Note `NDB': mysql-cluster. management client command `NODE_ID REPORT MEMORY' provided no output when NODE_ID was the node ID of a management or API node. Now, when this occurs, the management client responds with `Node NODE_ID: is not a data node'. (Bug #29485) * Performing *Note `DELETE': delete. operations after a data node had been shut down could lead to inconsistent data following a restart of the node. (Bug #26450) * `UPDATE IGNORE' could sometimes fail on *Note `NDB': mysql-cluster. tables due to the use of unitialized data when checking for duplicate keys to be ignored. (Bug #25817) *Changes in MySQL Cluster NDB 6.2.7 (5.1.22-ndb-6.2.7) * *Bugs fixed:* * It was possible in some cases for a node group to be `lost' due to missed local checkpoints following a system restart. (Bug #31525) * *Note `NDB': mysql-cluster. tables having names containing nonalphanumeric characters (such as ``$'') were not discovered correctly. (Bug #31470) * A node failure during a local checkpoint could lead to a subsequent failure of the cluster during a system restart. (Bug #31257) * A cluster restart could sometimes fail due to an issue with table IDs. (Bug #30975) * Transaction timeouts were not handled well in some circumstances, leading to excessive number of transactions being aborted unnecessarily. (Bug #30379) * In some cases, the cluster managment server logged entries multiple times following a restart of *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. (Bug #29565) * *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. `--help' did not display any information about the `-a' option. (Bug #29509) * The cluster log was formatted inconsistently and contained extraneous newline characters. (Bug #25064) *Changes in MySQL Cluster NDB 6.2.6 (5.1.22-ndb-6.2.6) * *Functionality added or changed:* * Mapping of *Note `NDB': mysql-cluster. error codes to MySQL storage engine error codes has been improved. (Bug #28423) *Bugs fixed:* * *Partitioning*: *Note `EXPLAIN PARTITIONS': explain. reported partition usage by queries on *Note `NDB': mysql-cluster. tables according to the standard MySQL hash function than the hash function used in the *Note `NDB': mysql-cluster. storage engine. (Bug #29550) * When an *Note `NDB': mysql-cluster. event was left behind but the corresponding table was later recreated and received a new table ID, the event could not be dropped. (Bug #30877) * Attempting to restore a backup made on a cluster host using one endian to a machine using the other endian could cause the cluster to fail. (Bug #29674) * The description of the `--print' option provided in the output from *Note `ndb_restore `--help' ': mysql-cluster-programs-ndb-restore. was incorrect. (Bug #27683) * Restoring a backup made on a cluster host using one endian to a machine using the other endian failed for *Note `BLOB': blob. and *Note `DATETIME': datetime. columns. (Bug #27543, Bug #30024) * An insufficiently descriptive and potentially misleading Error 4006 (`Connect failure - out of connection objects...') was produced when either of the following two conditions occurred: 1. There were no more transaction records in the transaction coordinator 2. An *Note `NDB': mysql-cluster. object in the NDB API was initialized with insufficient parallelism Separate error messages are now generated for each of these two cases. (Bug #11313) *Changes in MySQL Cluster NDB 6.2.5 (5.1.22-ndb-6.2.5) * *Functionality added or changed:* * The following improvements have been made in the *Note `ndb_size.pl': mysql-cluster-programs-ndb-size-pl. utility: * The script can now be used with multiple databases; lists of databases and tables can also be excluded from analysis. * Schema name information has been added to index table calculations. * The database name is now an optional parameter, the exclusion of which causes all databases to be examined. * If selecting from `INFORMATION_SCHEMA' fails, the script now attempts to fall back to *Note `SHOW TABLES': show-tables. * A `--real_table_name' option has been added; this designates a table to handle unique index size calculations. * The report title has been amended to cover cases where more than one database is being analyzed. Support for a `--socket' option was also added. For more information, see *Note mysql-cluster-programs-ndb-size-pl::. (Bug #28683, Bug #28253) * Online `ADD COLUMN', `ADD INDEX', and `DROP INDEX' operations can now be performed explicitly for *Note `NDB': mysql-cluster. tables--that is, without copying or locking of the affected tables--using `ALTER ONLINE TABLE'. Indexes can also be created and dropped online using *Note `CREATE INDEX': create-index. and *Note `DROP INDEX': drop-index, respectively, using the `ONLINE' keyword. You can force operations that would otherwise be performed online to be done offline using the `OFFLINE' keyword. Renaming of tables and columns for *Note `NDB': mysql-cluster. and `MyISAM' tables is performed in place without table copying. For more information, see *Note alter-table-online-operations::, *Note create-index::, and *Note drop-index::. * It is now possible to control whether fixed-width or variable-width storage is used for a given column of an *Note `NDB': mysql-cluster. table by means of the `COLUMN_FORMAT' specifier as part of the column's definition in a *Note `CREATE TABLE': create-table. or *Note `ALTER TABLE': alter-table. statement. It is also possible to control whether a given column of an *Note `NDB': mysql-cluster. table is stored in memory or on disk, using the `STORAGE' specifier as part of the column's definition in a *Note `CREATE TABLE': create-table. or *Note `ALTER TABLE': alter-table. statement. For permitted values and other information about `COLUMN_FORMAT' and `STORAGE', see *Note create-table::. * A new cluster management server startup option `--bind-address' makes it possible to restrict management client connections to *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. to a single host and port. For more information, see *Note mysql-cluster-programs-ndb-mgmd::. *Bugs fixed:* * When handling *Note `BLOB': blob. columns, the addition of read locks to the lock queue was not handled correctly. (Bug #30764) * Discovery of *Note `NDB': mysql-cluster. tables did not work correctly with `INFORMATION_SCHEMA'. (Bug #30667) * A file system close operation could fail during a node or system restart. (Bug #30646) * Using the `--ndb-cluster-connection-pool' option for *Note `mysqld': mysqld. caused DDL statements to be executed twice. (Bug #30598) * When creating an `NDB' table with a column that has `COLUMN_FORMAT = DYNAMIC', but the table tiself uses `ROW_FORMAT=FIXED', the table is considered dynamic, but any columns for which the row format is unspecified default to `FIXED'. Now in such cases the server issues the warning `Row format FIXED incompatible with dynamic attribute COLUMN_NAME'. (Bug #30276) * *Note `ndb_size.pl': mysql-cluster-programs-ndb-size-pl. failed on tables with *Note `FLOAT': numeric-types. columns whose definitions included commas (for example, `FLOAT(6,2)'). (Bug #29228) * Reads on *Note `BLOB': blob. columns were not locked when they needed to be to guarantee consistency. (Bug #29102) See also Bug #31482. * A query using joins between several large tables and requiring unique index lookups failed to complete, eventually returning `Uknown Error' after a very long period of time. This occurred due to inadequate handling of instances where the Transaction Coordinator ran out of `TransactionBufferMemory', when the cluster should have returned NDB error code 4012 (`Request ndbd time-out'). (Bug #28804) * An attempt to perform a `SELECT ... FROM INFORMATION_SCHEMA.TABLES' whose result included information about *Note `NDB': mysql-cluster. tables for which the user had no privileges crashed the MySQL Server on which the query was performed. (Bug #26793) * *Cluster API*: A call to `CHECK_TIMEDOUT_RET()' in `mgmapi.cpp' should have been a call to `DBUG_CHECK_TIMEDOUT_RET()'. (Bug #30681) *Changes in MySQL Cluster NDB 6.2.4 (5.1.19-ndb-6.2.4) * *Bugs fixed:* * When restarting a data node, queries could hang during that node's start phase 5, and continue only after the node had entered phase 6. (Bug #29364) * Replica redo logs were inconsistently handled during a system restart. (Bug #29354) * *Disk Data*: Performing Disk Data schema operations during a node restart could cause forced shutdowns of other data nodes. (Bug #29501) * *Disk Data*: Disk data meta-information that existed in *Note `ndbd': mysql-cluster-programs-ndbd. might not be visible to *Note `mysqld': mysqld. (Bug #28720) * *Disk Data*: The number of free extents was incorrectly reported for some tablespaces. (Bug #28642) *Changes in MySQL Cluster NDB 6.2.3 (5.1.19-ndb-6.2.3) * *Functionality added or changed:* * *Important Change*: The `TimeBetweenWatchdogCheckInitial' configuration parameter was added to enable setting of a separate watchdog timeout for memory allocation during startup of the data nodes. (Bug #28899) * *Cluster API*: *Important Change*: A new `NdbRecord' object has been added to the *Note `NDB': mysql-cluster. API. This object provides mapping to a record stored in *Note `NDB': mysql-cluster. * `auto_increment_increment' and `auto_increment_offset' are now supported for *Note `NDB': mysql-cluster. tables. (Bug #26342) * A `REPORT BackupStatus' command has been added in the cluster management client. This command enables you to obtain a backup status report at any time during a backup. For more about this command, see *Note mysql-cluster-mgm-client-commands::. * Reporting functionality has been significantly enhanced in this release: * A new configuration parameter `BackupReportFrequency' now makes it possible to cause the management client to provide status reports at regular intervals as well as for such reports to be written to the cluster log (depending on cluster event logging levels). * A new `REPORT' command has been added in the cluster management client. `REPORT BackupStatus' enables you to obtain a backup status report at any time during a backup. `REPORT MemoryUsage' reports the current data memory and index memory used by each data node. For more about the `REPORT' command, see *Note mysql-cluster-mgm-client-commands::. * *Note `ndb_restore': mysql-cluster-programs-ndb-restore. now provides running reports of its progress when restoring a backup. In addition, a complete report status report on the backup is written to the cluster log. * A new configuration parameter `ODirect' causes *Note `NDB': mysql-cluster. to attempt using `O_DIRECT' writes for LCP, backups, and redo logs, often lowering CPU usage. * *Note `ndb_restore': mysql-cluster-programs-ndb-restore. now provides running reports of its progress when restoring a backup. In addition, a complete report status report on the backup is written to the cluster log. * A new data node configuration parameter `BackupReportFrequency' now makes it possible to cause the management client to provide status reports at regular intervals as well as for such reports to be written to the cluster log (depending on cluster event logging levels). * A new memory allocator has been implemented for the *Note `NDB': mysql-cluster. kernel, which allocates memory to tables 32K page by 32K page rather than allocating it in variable-sized chunks as previously. This removes much of the memory overhead that was associated with the old memory allocator. *Bugs fixed:* * When a node failed to respond to a `COPY_GCI' signal as part of a global checkpoint, the master node was killed instead of the node that actually failed. (Bug #29331) * Memory corruption could occur due to a problem in the `DBTUP' kernel block. (Bug #29229) * A query having a large `IN(...)' or `NOT IN(...)' list in the `WHERE' condition on an *Note `NDB': mysql-cluster. table could cause *Note `mysqld': mysqld. to crash. (Bug #29185) * In the event that two data nodes in the same node group and participating in a GCP crashed before they had written their respective `P0.sysfile' files, `QMGR' could refuse to start, issuing an invalid `Insufficient nodes for restart' error instead. (Bug #29167) * An invalid comparison made during `REDO' validation that could lead to an `Error while reading REDO log' condition. (Bug #29118) * Attempting to restore a `NULL' row to a *Note `VARBINARY': binary-varbinary. column caused *Note `ndb_restore': mysql-cluster-programs-ndb-restore. to fail. (Bug #29103) * *Note `ndb_error_reporter': mysql-cluster-programs-ndb-error-reporter. now preserves timestamps on files. (Bug #29074) * The wrong data pages were sometimes invalidated following a global checkpoint. (Bug #29067) * If at least 2 files were involved in `REDO' invalidation, then file 0 of page 0 was not updated and so pointed to an invalid part of the redo log. (Bug #29057) * It is now possible to set the maximum size of the allocation unit for table memory using the `MaxAllocate' configuration parameter. (Bug #29044) * When shutting down *Note `mysqld': mysqld, the *Note `NDB': mysql-cluster. binlog process was not shut down before log cleanup began. (Bug #28949) * A corrupt schema file could cause a `File already open' error. (Bug #28770) * Having large amounts of memory locked caused swapping to disk. (Bug #28751) * Setting `InitialNoOfOpenFiles' equal to `MaxNoOfOpenFiles' caused an error. This was due to the fact that the actual value of `MaxNoOfOpenFiles' as used by the cluster was offset by 1 from the value set in `config.ini'. (Bug #28749) * LCP files were not removed following an initial system restart. (Bug #28726) * `UPDATE IGNORE' statements involving the primary keys of multiple tables could result in data corruption. (Bug #28719) * A race condition could result when nonmaster nodes (in addition to the master node) tried to update active status due to a local checkpoint (that is, between `NODE_FAILREP' and `COPY_GCIREQ' events). Now only the master updates the active status. (Bug #28717) * A fast global checkpoint under high load with high usage of the redo buffer caused data nodes to fail. (Bug #28653) * The management client's response to `START BACKUP WAIT COMPLETED' did not include the backup ID. (Bug #27640) * *Disk Data*: When dropping a page, the stack's bottom entry could sometime be left `cold' rather than `hot', violating the rules for stack pruning. (Bug #29176) * *Disk Data*: When loading data into a cluster following a version upgrade, the data nodes could forcibly shut down due to page and buffer management failures (that is, `ndbrequire' failures in `PGMAN'). (Bug #28525) * *Disk Data*: Repeated *Note `INSERT': insert. and *Note `DELETE': delete. operations on a Disk Data table having one or more large *Note `VARCHAR': char. columns could cause data nodes to fail. (Bug #20612) * *Cluster API*: The timeout set using the MGM API `ndb_mgm_set_timeout()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-set-timeout.html) function was incorrectly interpreted as seconds rather than as milliseconds. (Bug #29063) * *Cluster API*: An invalid error code could be set on transaction objects by *Note `BLOB': blob. handling code. (Bug #28724) *Changes in MySQL Cluster NDB 6.2.2 (5.1.18-ndb-6.2.2) * *Functionality added or changed:* * New cluster management client `DUMP' commands were added to aid in tracking transactions, scan operations, and locks. See `DUMP 2350' (http://dev.mysql.com/doc/ndbapi/en/ndb-internals-dump-command-2350.html), `DUMP 2352' (http://dev.mysql.com/doc/ndbapi/en/ndb-internals-dump-command-2352.html), and `DUMP 2550' (http://dev.mysql.com/doc/ndbapi/en/ndb-internals-dump-command-2550.html), for more information. * Added the *Note `mysqld': mysqld. option `--ndb-cluster-connection-pool' that enables a single MySQL server to use multiple connections to the cluster. This enables scaling out using multiple MySQL clients per SQL node instead of or in addition to using multiple SQL nodes with the cluster. For more information about this option, see *Note mysql-cluster-options-variables::. *Changes in MySQL Cluster NDB 6.2.1 (5.1.18-ndb-6.2.1) * *Bugs fixed:* * Multiple operations involving deletes followed by reads were not handled correctly. *Note*: This issue could also affect MySQL Cluster Replication. (Bug #28276) * *Cluster API*: Using `NdbBlob::writeData()' to write data in the middle of an existing blob value (that is, updating the value) could overwrite some data past the end of the data to be changed. (Bug #27018) *Changes in MySQL Cluster NDB 6.2.0 (5.1.16-ndb-6.2.0) * *Functionality added or changed:* * An `--ndb-wait-connected' option has been added for *Note `mysqld': mysqld. When used, it causes *Note `mysqld': mysqld. wait a specified amount of time to be connected to the cluster before accepting client connections. * *Cluster API*: The `Ndb::startTransaction()' method now provides an alternative interface for starting a transaction. * *Cluster API*: It is now possible to iterate over all existing *Note `NDB': mysql-cluster. objects using three new methods of the `Ndb_cluster_connection' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndb-cluster-connection.html#ndb-ndb-cluster-connection) class: * `lock_ndb_objects()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndb-cluster-connection-methods.html#ndb-ndb-cluster-connection-lock-ndb-objects) * `get_next_ndb_object()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndb-cluster-connection-methods.html#ndb-ndb-cluster-connection-get-next-ndb-object) * `unlock_ndb_objects()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndb-cluster-connection-methods.html#ndb-ndb-cluster-connection-unlock-ndb-objects)  File: manual.info, Node: mysql-cluster-news-6-1-series, Prev: mysql-cluster-news-6-2-series, Up: mysql-cluster-news-series 17.7.7.5 Changes in the MySQL Cluster NDB 6.1 Series .................................................... This section contains unified change history highlights for all MySQL Cluster releases based on version 6.1 of the *Note `NDBCLUSTER': mysql-cluster. storage engine through MySQL Cluster NDB 5.1.15-ndb-6.1.23. Included are all changelog entries in the categories _MySQL Cluster_, _Disk Data_, and _Cluster API_. For an overview of features that were added in MySQL Cluster NDB 6.1, see *Note mysql-cluster-development-5-1-ndb-6-1::. *Note*: MySQL Cluster NDB 6.1 is no longer being developed or maintained, and the information presented in this section should be considered to be of historical interest only. If you are using MySQL Cluster NDB 6.1, you should upgrade as soon as possible to the most recent version of MySQL Cluster NDB 6.2 or later MySQL Cluster release series. * Changes in MySQL Cluster NDB 6.1.23 (5.1.15-ndb-6.1.23) * Changes in MySQL Cluster NDB 6.1.22 (5.1.15-ndb-6.1.22) * Changes in MySQL Cluster NDB 6.1.21 (5.1.15-ndb-6.1.21) * Changes in MySQL Cluster NDB 6.1.19 (5.1.15-ndb-6.1.19) * Changes in MySQL Cluster NDB 6.1.18 (5.1.15-ndb-6.1.18) * Changes in MySQL Cluster NDB 6.1.17 (5.1.15-ndb-6.1.17) * Changes in MySQL Cluster NDB 6.1.16 (5.1.15-ndb-6.1.16) * Changes in MySQL Cluster NDB 6.1.15 (5.1.15-ndb-6.1.15) * Changes in MySQL Cluster NDB 6.1.14 (5.1.15-ndb-6.1.14) * Changes in MySQL Cluster NDB 6.1.13 (5.1.15-ndb-6.1.13) * Changes in MySQL Cluster NDB 6.1.12 (5.1.15-ndb-6.1.12) * Changes in MySQL Cluster NDB 6.1.11 (5.1.15-ndb-6.1.11) * Changes in MySQL Cluster NDB 6.1.10 (5.1.15-ndb-6.1.10) * Changes in MySQL Cluster NDB 6.1.9 (5.1.15-ndb-6.1.9) * Changes in MySQL Cluster NDB 6.1.8 (5.1.15-ndb-6.1.8) * Changes in MySQL Cluster NDB 6.1.7 (5.1.15-ndb-6.1.7) * Changes in MySQL Cluster NDB 6.1.6 (5.1.15-ndb-6.1.6) * Changes in MySQL Cluster NDB 6.1.5 (5.1.15-ndb-6.1.5) * Changes in MySQL Cluster NDB 6.1.4 (5.1.15-ndb-6.1.4) * Changes in MySQL Cluster NDB 6.1.3 (5.1.15-ndb-6.1.3) * Changes in MySQL Cluster NDB 6.1.2 (5.1.15-ndb-6.1.2) * Changes in MySQL Cluster NDB 6.1.1 (5.1.15-ndb-6.1.1) * Changes in MySQL Cluster NDB 6.1.0 (5.1.14-ndb-6.1.0) *Changes in MySQL Cluster NDB 6.1.23 (5.1.15-ndb-6.1.23) * *Bugs fixed:* * The *Note `NDB': mysql-cluster. storage engine code was not safe for strict-alias optimization in `gcc' 4.2.1. (Bug #31761) *Changes in MySQL Cluster NDB 6.1.22 (5.1.15-ndb-6.1.22) * *Bugs fixed:* * It was possible in some cases for a node group to be `lost' due to missed local checkpoints following a system restart. (Bug #31525) *Changes in MySQL Cluster NDB 6.1.21 (5.1.15-ndb-6.1.21) * *Bugs fixed:* * A node failure during a local checkpoint could lead to a subsequent failure of the cluster during a system restart. (Bug #31257) * A cluster restart could sometimes fail due to an issue with table IDs. (Bug #30975) *Changes in MySQL Cluster NDB 6.1.19 (5.1.15-ndb-6.1.19) * *Functionality added or changed:* * Whenever a TCP send buffer is over 80% full, temporary error 1218 (`Send Buffers overloaded in NDB kernel') is now returned. See SendBufferMemory for more information. *Changes in MySQL Cluster NDB 6.1.18 (5.1.15-ndb-6.1.18) * *Bugs fixed:* * When restarting a data node, queries could hang during that node's start phase 5, and continue only after the node had entered phase 6. (Bug #29364) * *Disk Data*: Disk data meta-information that existed in *Note `ndbd': mysql-cluster-programs-ndbd. might not be visible to *Note `mysqld': mysqld. (Bug #28720) * *Disk Data*: The number of free extents was incorrectly reported for some tablespaces. (Bug #28642) *Changes in MySQL Cluster NDB 6.1.17 (5.1.15-ndb-6.1.17) * *Bugs fixed:* * Replica redo logs were inconsistently handled during a system restart. (Bug #29354) *Changes in MySQL Cluster NDB 6.1.16 (5.1.15-ndb-6.1.16) * *Bugs fixed:* * When a node failed to respond to a `COPY_GCI' signal as part of a global checkpoint, the master node was killed instead of the node that actually failed. (Bug #29331) * An invalid comparison made during `REDO' validation that could lead to an `Error while reading REDO log' condition. (Bug #29118) * The wrong data pages were sometimes invalidated following a global checkpoint. (Bug #29067) * If at least 2 files were involved in `REDO' invalidation, then file 0 of page 0 was not updated and so pointed to an invalid part of the redo log. (Bug #29057) * *Disk Data*: When dropping a page, the stack's bottom entry could sometime be left `cold' rather than `hot', violating the rules for stack pruning. (Bug #29176) *Changes in MySQL Cluster NDB 6.1.15 (5.1.15-ndb-6.1.15) * *Bugs fixed:* * Memory corruption could occur due to a problem in the `DBTUP' kernel block. (Bug #29229) *Changes in MySQL Cluster NDB 6.1.14 (5.1.15-ndb-6.1.14) * *Bugs fixed:* * In the event that two data nodes in the same node group and participating in a GCP crashed before they had written their respective `P0.sysfile' files, `QMGR' could refuse to start, issuing an invalid `Insufficient nodes for restart' error instead. (Bug #29167) *Changes in MySQL Cluster NDB 6.1.13 (5.1.15-ndb-6.1.13) * *Bugs fixed:* * *Cluster API*: `NdbApi.hpp' depended on `ndb_global.h', which was not actually installed, causing the compilation of programs that used `NdbApi.hpp' to fail. (Bug #35853) *Changes in MySQL Cluster NDB 6.1.12 (5.1.15-ndb-6.1.12) * *Functionality added or changed:* * New cluster management client `DUMP' commands were added to aid in tracking transactions, scan operations, and locks. See `DUMP 2350' (http://dev.mysql.com/doc/ndbapi/en/ndb-internals-dump-command-2350.html), `DUMP 2352' (http://dev.mysql.com/doc/ndbapi/en/ndb-internals-dump-command-2352.html), and `DUMP 2550' (http://dev.mysql.com/doc/ndbapi/en/ndb-internals-dump-command-2550.html). *Bugs fixed:* * It is now possible to set the maximum size of the allocation unit for table memory using the `MaxAllocate' configuration parameter. (Bug #29044) *Changes in MySQL Cluster NDB 6.1.11 (5.1.15-ndb-6.1.11) * *Functionality added or changed:* * *Important Change*: The `TimeBetweenWatchdogCheckInitial' configuration parameter was added to enable setting of a separate watchdog timeout for memory allocation during startup of the data nodes. (Bug #28899) * A new configuration parameter `ODirect' causes *Note `NDB': mysql-cluster. to attempt using `O_DIRECT' writes for LCP, backups, and redo logs, often lowering CPU usage. *Bugs fixed:* * Having large amounts of memory locked caused swapping to disk. (Bug #28751) * LCP files were not removed following an initial system restart. (Bug #28726) * *Disk Data*: Repeated *Note `INSERT': insert. and *Note `DELETE': delete. operations on a Disk Data table having one or more large *Note `VARCHAR': char. columns could cause data nodes to fail. (Bug #20612) *Changes in MySQL Cluster NDB 6.1.10 (5.1.15-ndb-6.1.10) * *Functionality added or changed:* * A new `times' printout was added in the *Note `ndbd': mysql-cluster-programs-ndbd. watchdog thread. * Some unneeded printouts in the *Note `ndbd': mysql-cluster-programs-ndbd. out file were removed. *Bugs fixed:* * A regression in the heartbeat monitoring code could lead to node failure under high load. This issue affected MySQL 5.1.19 and MySQL Cluster NDB 6.1.10 only. (Bug #28783) * A corrupt schema file could cause a `File already open' error. (Bug #28770) * Setting `InitialNoOfOpenFiles' equal to `MaxNoOfOpenFiles' caused an error. This was due to the fact that the actual value of `MaxNoOfOpenFiles' as used by the cluster was offset by 1 from the value set in `config.ini'. (Bug #28749) * A race condition could result when nonmaster nodes (in addition to the master node) tried to update active status due to a local checkpoint (that is, between `NODE_FAILREP' and `COPY_GCIREQ' events). Now only the master updates the active status. (Bug #28717) * A fast global checkpoint under high load with high usage of the redo buffer caused data nodes to fail. (Bug #28653) * *Disk Data*: When loading data into a cluster following a version upgrade, the data nodes could forcibly shut down due to page and buffer management failures (that is, `ndbrequire' failures in `PGMAN'). (Bug #28525) *Changes in MySQL Cluster NDB 6.1.9 (5.1.15-ndb-6.1.9) * *Bugs fixed:* * When an API node sent more than 1024 signals in a single batch, *Note `NDB': mysql-cluster. would process only the first 1024 of these, and then hang. (Bug #28443) * *Disk Data*: The cluster backup process scanned in `ACC' index order, which had bad effects for disk data. (Bug #28593) *Changes in MySQL Cluster NDB 6.1.8 (5.1.15-ndb-6.1.8) * *Bugs fixed:* * Local checkpoint files relating to dropped *Note `NDB': mysql-cluster. tables were not removed. (Bug #28348) * Repeated insertion of data generated by *Note `mysqldump': mysqldump. into *Note `NDB': mysql-cluster. tables could eventually lead to failure of the cluster. (Bug #27437) * *Disk Data*: Extremely large inserts into Disk Data tables could lead to data node failure in some circumstances. (Bug #27942) * *Cluster API*: In a multi-operation transaction, a delete operation followed by the insertion of an implicit `NULL' failed to overwrite an existing value. (Bug #20535) *Changes in MySQL Cluster NDB 6.1.7 (5.1.15-ndb-6.1.7) * *Functionality added or changed:* * *Cluster Replication*: *Incompatible Change*: The schema for the `ndb_apply_status' table in the `mysql' system database has changed. When upgrading to this release from a previous MySQL Cluster NDB 6.x or mainline MySQL 5.1 release, you must drop the `mysql.ndb_apply_status' table, then restart the server for the table to be re-created with the new schema. See *Note mysql-cluster-replication-schema::, for additional information. *Bugs fixed:* * The cluster waited 30 seconds instead of 30 milliseconds before reading table statistics. (Bug #28093) * Under certain rare circumstances, *Note `ndbd': mysql-cluster-programs-ndbd. could get caught in an infinite loop when one transaction took a read lock and then a second transaction attempted to obtain a write lock on the same tuple in the lock queue. (Bug #28073) * Under some circumstances, a node restart could fail to update the Global Checkpoint Index (GCI). (Bug #28023) * An *Note `INSERT': insert. followed by a delete *Note `DELETE': delete. on the same *Note `NDB': mysql-cluster. table caused a memory leak. (Bug #27756) This regression was introduced by Bug #20612. * Under certain rare circumstances performing a *Note `DROP TABLE': drop-table. or *Note `TRUNCATE TABLE': truncate-table. on an *Note `NDB': mysql-cluster. table could cause a node failure or forced cluster shutdown. (Bug #27581) * Memory usage of a *Note `mysqld': mysqld. process grew even while idle. (Bug #27560) * Performing a delete followed by an insert during a local checkpoint could cause a `Rowid already allocated' error. (Bug #27205) * *Cluster Replication*: *Disk Data*: An issue with replication of Disk Data tables could in some cases lead to node failure. (Bug #28161) * *Disk Data*: Changes to a Disk Data table made as part of a transaction could not be seen by the client performing the changes until the transaction had been committed. (Bug #27757) * *Disk Data*: When restarting a data node following the creation of a large number of Disk Data objects (approximately 200 such objects), the cluster could not assign a node ID to the restarting node. (Bug #25741) * *Disk Data*: Changing a column specification or issuing a *Note `TRUNCATE TABLE': truncate-table. statement on a Disk Data table caused the table to become an in-memory table. This fix supersedes an incomplete fix that was made for this issue in MySQL 5.1.15. (Bug #24667, Bug #25296) * *Cluster API*: An issue with the way in which the `Dictionary::listEvents()' method freed resources could sometimes lead to memory corruption. (Bug #27663) *Changes in MySQL Cluster NDB 6.1.6 (5.1.15-ndb-6.1.6) * *Functionality added or changed:* * *Cluster Replication*: *Incompatible Change*: The schema for the `ndb_apply_status' table in the `mysql' system database has changed. When upgrading to this release from a previous MySQL Cluster NDB 6.x or mainline MySQL 5.1 release, you must drop the `mysql.ndb_apply_status' table, then restart the server for the table to be re-created with the new schema. See *Note mysql-cluster-replication-schema::, for additional information. *Bugs fixed:* * A data node failing while another data node was restarting could leave the cluster in an inconsistent state. In certain rare cases, this could lead to a race condition and the eventual forced shutdown of the cluster. (Bug #27466) * It was not possible to set `LockPagesInMainMemory' equal to `0'. (Bug #27291) * A race condition could sometimes occur if the node acting as master failed while node IDs were still being allocated during startup. (Bug #27286) * When a data node was taking over as the master node, a race condition could sometimes occur as the node was assuming responsibility for handling of global checkpoints. (Bug #27283) * *Note `mysqld': mysqld. could crash shortly after a data node failure following certain DML operations. (Bug #27169) * The same failed request from an API node could be handled by the cluster multiple times, resulting in reduced performance. (Bug #27087) * The failure of a data node while restarting could cause other data nodes to hang or crash. (Bug #27003) * *Note `mysqld': mysqld. processes would sometimes crash under high load. *Note*: This fix improves on and replaces a fix for this bug that was made in MySQL Cluster NDB 6.1.5. (Bug #26825) * *Disk Data*: *Note `DROP INDEX': drop-index. on a Disk Data table did not always move data from memory into the tablespace. (Bug #25877) * *Cluster API*: An issue with the way in which the `Dictionary::listEvents()' method freed resources could sometimes lead to memory corruption. (Bug #27663) * *Cluster API*: A delete operation using a scan followed by an insert using a scan could cause a data node to fail. (Bug #27203) *Changes in MySQL Cluster NDB 6.1.5 (5.1.15-ndb-6.1.5) * *Functionality added or changed:* * *Cluster Replication*: *Incompatible Change*: The schema for the `ndb_apply_status' table in the `mysql' system database has changed. When upgrading to this release from a previous MySQL Cluster NDB 6.x or mainline MySQL 5.1 release, you must drop the `mysql.ndb_apply_status' table, then restart the server for the table to be re-created with the new schema. See *Note mysql-cluster-replication-schema::, for additional information. *Bugs fixed:* * Creating a table on one SQL node while in single user mode caused other SQL nodes to crash. (Bug #26997) * *Note `mysqld': mysqld. processes would sometimes crash under high load. *Note*: This fix was reverted in MySQL Cluster NDB 6.1.6. (Bug #26825) * An infinite loop in an internal logging function could cause trace logs to fill up with `Unknown Signal type' error messages and thus grow to unreasonable sizes. (Bug #26720) * *Disk Data*: When creating a log file group, setting `INITIAL_SIZE' to less than `UNDO_BUFFER_SIZE' caused data nodes to crash. (Bug #25743) *Changes in MySQL Cluster NDB 6.1.4 (5.1.15-ndb-6.1.4) * *Functionality added or changed:* * An `--ndb-wait-connected' option has been added for *Note `mysqld': mysqld. When used, it causes *Note `mysqld': mysqld. wait a specified amount of time to be connected to the cluster before accepting client connections. * *Cluster API*: It is now possible to specify the transaction coordinator when starting a transaction. See `Ndb::startTransaction()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndb-methods.html#ndb-ndb-starttransaction), for more information. * *Cluster API*: It is now possible to iterate over all existing *Note `NDB': mysql-cluster. objects using three new methods of the `Ndb_cluster_connection' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndb-cluster-connection.html#ndb-ndb-cluster-connection) class: * `lock_ndb_objects()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndb-cluster-connection-methods.html#ndb-ndb-cluster-connection-lock-ndb-objects) * `get_next_ndb_object()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndb-cluster-connection-methods.html#ndb-ndb-cluster-connection-get-next-ndb-object) * `unlock_ndb_objects()' (http://dev.mysql.com/doc/ndbapi/en/ndb-ndb-cluster-connection-methods.html#ndb-ndb-cluster-connection-unlock-ndb-objects) *Bugs fixed:* * Using only the `--print_data' option (and no other options) with *Note `ndb_restore': mysql-cluster-programs-ndb-restore. caused *Note `ndb_restore': mysql-cluster-programs-ndb-restore. to fail. (Bug #26741) This regression was introduced by Bug #14612. * An inadvertent use of unaligned data caused *Note `ndb_restore': mysql-cluster-programs-ndb-restore. to fail on some 64-bit platforms, including Sparc and Itanium-2. (Bug #26739) *Changes in MySQL Cluster NDB 6.1.3 (5.1.15-ndb-6.1.3) * *Functionality added or changed:* * The *Note `ndbd_redo_log_reader': mysql-cluster-programs-ndbd-redo-log-reader. utility is now part of the default build. For more information, see *Note mysql-cluster-programs-ndbd-redo-log-reader::. * The *Note `ndb_show_tables': mysql-cluster-programs-ndb-show-tables. utility now displays information about table events. See *Note mysql-cluster-programs-ndb-show-tables::, for more information. * *Cluster API*: A new `listEvents()' method has been added to the `Dictionary' class. *Bugs fixed:* * An invalid pointer was returned following a `FSCLOSECONF' signal when accessing the REDO logs during a node restart or system restart. (Bug #26515) * The InvalidUndoBufferSize error used the same error code (763) as the IncompatibleVersions error. InvalidUndoBufferSize now uses its own error code (779). (Bug #26490) * The failure of a data node when restarting it with `--initial' could lead to failures of subsequent data node restarts. (Bug #26481) * Takeover for local checkpointing due to multiple failures of master nodes was sometimes incorrectly handled. (Bug #26457) * The `LockPagesInMainMemory' parameter was not read until after distributed communication had already started between cluster nodes. When the value of this parameter was `1', this could sometimes result in data node failure due to missed heartbeats. (Bug #26454) * Under some circumstances, following the restart of a management node, all data nodes would connect to it normally, but some of them subsequently failed to log any events to the management node. (Bug #26293) * No appropriate error message was provided when there was insufficient REDO log file space for the cluster to start. (Bug #25801) * A memory allocation failure in `SUMA' (the cluster Subscription Manager) could cause the cluster to crash. (Bug #25239) * The message `Error 0 in readAutoIncrementValue(): no Error' was written to the error log whenever *Note `SHOW TABLE STATUS': show-table-status. was performed on a Cluster table that did not have an `AUTO_INCREMENT' column. *Note*: This improves on and supersedes an earlier fix that was made for this issue in MySQL 5.1.12. (Bug #21033) * *Disk Data*: A memory overflow could occur with tables having a large amount of data stored on disk, or with queries using a very high degree of parallelism on Disk Data tables. (Bug #26514) * *Disk Data*: Use of a tablespace whose `INITIAL_SIZE' was greater than 1 GB could cause the cluster to crash. (Bug #26487) *Changes in MySQL Cluster NDB 6.1.2 (5.1.15-ndb-6.1.2) * *Bugs fixed:* * Using node IDs greater than 48 could sometimes lead to incorrect memory access and a subsequent forced shutdown of the cluster. (Bug #26267) *Changes in MySQL Cluster NDB 6.1.1 (5.1.15-ndb-6.1.1) * *Functionality added or changed:* * A single cluster can now support up to 255 API nodes, including MySQL servers acting as SQL nodes. See *Note mysql-cluster-limitations-exclusive-to-cluster::, for more information. *Bugs fixed:* * A memory leak could cause problems during a node or cluster shutdown or failure. (Bug #25997) * *Cluster API*: *Disk Data*: A delete and a read performed in the same operation could cause one or more data nodes to crash. This could occur when the operation affected more than 5 columns concurrently, or when one or more of the columns was of the *Note `VARCHAR': char. type and was stored on disk. (Bug #25794) * *Cluster API*: *Disk Data*: A delete and a read performed in the same operation could cause one or more data nodes to crash. This could occur when the operation affected more than 5 columns concurrently, or when one or more of the columns was of the *Note `VARCHAR': char. type and was stored on disk. (Bug #25794) *Changes in MySQL Cluster NDB 6.1.0 (5.1.14-ndb-6.1.0) * *Functionality added or changed:* * A new configuration parameter `MemReportFrequency' enables additional control of data node memory usage. Previously, only warnings at predetermined percentages of memory allocation were given; setting this parameter enables that behavior to be overridden. *Bugs fixed:* * When a data node was shut down using the management client `STOP' command, a connection event (`NDB_LE_Connected') was logged instead of a disconnection event (`NDB_LE_Disconnected'). (Bug #22773) * *Note `SELECT': select. statements with a *Note `BLOB': blob. or *Note `TEXT': blob. column in the selected column list and a `WHERE' condition including a primary key lookup on a *Note `VARCHAR': char. primary key produced empty result sets. (Bug #19956) * *Disk Data*: *Note `MEDIUMTEXT': blob. columns of Disk Data tables were stored in memory rather than on disk, even if the columns were not indexed. (Bug #25001) * *Disk Data*: Performing a node restart with a newly dropped Disk Data table could lead to failure of the node during the restart. (Bug #24917) * *Disk Data*: When restoring from backup a cluster containing any Disk Data tables with hidden primary keys, a node failure resulted which could lead to a crash of the cluster. (Bug #24166) * *Disk Data*: Repeated `CREATE', `DROP', or *Note `TRUNCATE TABLE': truncate-table. in various combinations with system restarts between these operations could lead to the eventual failure of a system restart. (Bug #21948) * *Disk Data*: Extents that should have been available for re-use following a *Note `DROP TABLE': drop-table. operation were not actually made available again until after the cluster had performed a local checkpoint. (Bug #17605) * *Cluster API*: Invoking the `NdbTransaction::execute()' method using execution type `Commit' and abort option `AO_IgnoreError' could lead to a crash of the transaction coordinator (`DBTC'). (Bug #25090) * *Cluster API*: A unique index lookup on a nonexistent tuple could lead to a data node timeout (error 4012). (Bug #25059) * *Cluster API*: When using the `NdbTransaction::execute()' method, a very long timeout (greater than 5 minutes) could result if the last data node being polled was disconnected from the cluster. (Bug #24949) * *Cluster API*: Due to an error in the computation of table fragment arrays, some transactions were not executed from the correct starting point. (Bug #24914)  File: manual.info, Node: partitioning, Next: stored-programs-views, Prev: mysql-cluster, Up: Top 18 Partitioning *************** * Menu: * partitioning-overview:: Overview of Partitioning in MySQL * partitioning-types:: Partitioning Types * partitioning-management:: Partition Management * partitioning-pruning:: Partition Pruning * partitioning-limitations:: Restrictions and Limitations on Partitioning This chapter discusses MySQL's implementation of _user-defined partitioning_. You can determine whether your MySQL Server supports partitioning by means of a *Note `SHOW VARIABLES': show-variables. statement such as this one: mysql> SHOW VARIABLES LIKE '%partition%'; +-------------------+-------+ | Variable_name | Value | +-------------------+-------+ | have_partitioning | YES | +-------------------+-------+ 1 row in set (0.00 sec) *Note*: Prior to MySQL 5.1.6, this variable was named `have_partition_engine'. (Bug#16718) You can also check the output of the *Note `SHOW PLUGINS': show-plugins. statement, as shown here: mysql> SHOW PLUGINS; +------------+----------+----------------+---------+---------+ | Name | Status | Type | Library | License | +------------+----------+----------------+---------+---------+ | binlog | ACTIVE | STORAGE ENGINE | NULL | GPL | *| partition | ACTIVE | STORAGE ENGINE | NULL | GPL |* | ARCHIVE | ACTIVE | STORAGE ENGINE | NULL | GPL | | BLACKHOLE | ACTIVE | STORAGE ENGINE | NULL | GPL | | CSV | ACTIVE | STORAGE ENGINE | NULL | GPL | | FEDERATED | DISABLED | STORAGE ENGINE | NULL | GPL | | MEMORY | ACTIVE | STORAGE ENGINE | NULL | GPL | | InnoDB | ACTIVE | STORAGE ENGINE | NULL | GPL | | MRG_MYISAM | ACTIVE | STORAGE ENGINE | NULL | GPL | | MyISAM | ACTIVE | STORAGE ENGINE | NULL | GPL | | ndbcluster | DISABLED | STORAGE ENGINE | NULL | GPL | +------------+----------+----------------+---------+---------+ 11 rows in set (0.00 sec) If you do not see the `have_partitioning' variable with the value `YES' listed in the output of an appropriate *Note `SHOW VARIABLES': show-variables. statement, or if you do not see the `partition' plugin listed with the value `ACTIVE' for the `Status' column in the output of *Note `SHOW PLUGINS': show-plugins. (show in bold text in the example just given), then your version of MySQL was not built with partitioning support. MySQL 5.1 Community binaries provided by Oracle include partitioning support. For information about partitioning support offered in commercial MySQL Server binaries, see `MySQL Enterprise Server 5.1' on the MySQL Web site at http://www.mysql.com/products/enterprise/server.html. If you are compiling MySQL 5.1 from source, the build must be configured using `--with-partition' to enable partitioning. Using `--with-plugins=max' to configure the build includes this option automatically. If your MySQL binary is built with partitioning support, nothing further needs to be done to enable it (for example, no special entries are required in your `my.cnf' file). If you want to disable partitioning support, you can start the MySQL Server with the `--skip-partition' option, in which case the value of `have_partitioning' is `DISABLED'. However, if you do this, you cannot access any partitioned tables until the server is once again restarted without the `--skip-partition' option. An introduction to partitioning and partitioning concepts may be found in *Note partitioning-overview::. MySQL supports several types of partitioning, which are discussed in *Note partitioning-types::, as well as subpartitioning, which is described in *Note partitioning-subpartitions::. Methods of adding, removing, and altering partitions in existing partitioned tables are covered in *Note partitioning-management::. Table maintenance commands for use with partitioned tables are discussed in *Note partitioning-maintenance::. Beginning with MySQL 5.1.6, the *Note `PARTITIONS': partitions-table. table in the `INFORMATION_SCHEMA' database provides information about partitions and partitioned tables. See *Note partitions-table::, for more information; for some examples of queries against this table, see *Note partitioning-handling-nulls::. *Important*: Partitioned tables created with MySQL versions prior to 5.1.6 cannot be read by a 5.1.6 or later MySQL Server. In addition, the *Note `INFORMATION_SCHEMA.TABLES': tables-table. table cannot be used if such tables are present on a 5.1.6 server. Beginning with MySQL 5.1.7, a suitable warning message is generated instead, to alert the user that incompatible partitioned tables have been found by the server. If you are using partitioned tables which were created in MySQL 5.1.5 or earlier, be sure to see *Note news-5-1-6:: for more information and suggested workarounds _before_ upgrading to MySQL 5.1.6 or later. For known issues with partitioning in MySQL 5.1, see *Note partitioning-limitations::. You may also find the following resources to be useful when working with partitioned tables. Additional Resources Other sources of information about user-defined partitioning in MySQL include the following: * MySQL Partitioning Forum (http://forums.mysql.com/list.php?106) This is the official discussion forum for those interested in or experimenting with MySQL Partitioning technology. It features announcements and updates from MySQL developers and others. It is monitored by members of the Partitioning Development and Documentation Teams. * Mikael Ronstro"m's Blog (http://mikaelronstrom.blogspot.com/) MySQL Partitioning Architect and Lead Developer Mikael Ronstro"m frequently posts articles here concerning his work with MySQL Partitioning and MySQL Cluster. * PlanetMySQL (http://www.planetmysql.org/) A MySQL news site featuring MySQL-related blogs, which should be of interest to anyone using my MySQL. We encourage you to check here for links to blogs kept by those working with MySQL Partitioning, or to have your own blog added to those covered. MySQL 5.1 binaries are available from `http://dev.mysql.com/downloads/mysql/5.1.html'. However, for the latest partitioning bugfixes and feature additions, you can obtain the source from our Bazaar repository. To enable partitioning, you need to compile the server using the `--with-partition' option. For more information about building MySQL, see *Note source-installation::. If you have problems compiling a partitioning-enabled MySQL 5.1 build, check the MySQL Partitioning Forum (http://forums.mysql.com/list.php?106) and ask for assistance there if you do not find a solution to your problem already posted.  File: manual.info, Node: partitioning-overview, Next: partitioning-types, Prev: partitioning, Up: partitioning 18.1 Overview of Partitioning in MySQL ====================================== This section provides a conceptual overview of partitioning in MySQL 5.1. For information on partitioning restrictions and feature limitations, see *Note partitioning-limitations::. The SQL standard does not provide much in the way of guidance regarding the physical aspects of data storage. The SQL language itself is intended to work independently of any data structures or media underlying the schemas, tables, rows, or columns with which it works. Nonetheless, most advanced database management systems have evolved some means of determining the physical location to be used for storing specific pieces of data in terms of the file system, hardware or even both. In MySQL, the `InnoDB' storage engine has long supported the notion of a tablespace, and the MySQL Server, even prior to the introduction of partitioning, could be configured to employ different physical directories for storing different databases (see *Note symbolic-links::, for an explanation of how this is done). _Partitioning_ takes this notion a step further, by enabling you to distribute portions of individual tables across a file system according to rules which you can set largely as needed. In effect, different portions of a table are stored as separate tables in different locations. The user-selected rule by which the division of data is accomplished is known as a _partitioning function_, which in MySQL can be the modulus, simple matching against a set of ranges or value lists, an internal hashing function, or a linear hashing function. The function is selected according to the partitioning type specified by the user, and takes as its parameter the value of a user-supplied expression. This expression can be a column value, a function acting on one or more column values, or a set of one or more column values, depending on the type of partitioning that is used. In the case of `RANGE', `LIST', and [`LINEAR'] `HASH' partitioning, the value of the partitioning column is passed to the partitioning function, which returns an integer value representing the number of the partition in which that particular record should be stored. This function must be nonconstant and nonrandom. It may not contain any queries, but may use an SQL expression that is valid in MySQL, as long as that expression returns either `NULL' or an integer INTVAL such that -MAXVALUE <= INTVAL <= MAXVALUE (`MAXVALUE' is used to represent the least upper bound for the type of integer in question. `-MAXVALUE' represents the greatest lower bound.) For [`LINEAR'] `KEY', the partitioning expression consists of a list of one or more columns, and the partitioning function is supplied by MySQL. For more information about permitted partitioning column types and partitioning functions, see *Note partitioning-types::, as well as *Note create-table::, which provides partitioning syntax descriptions and additional examples. For information about restrictions on partitioning functions, see *Note partitioning-limitations-functions::. This is known as _horizontal partitioning_--that is, different rows of a table may be assigned to different physical partitions. MySQL 5.1 does not support _vertical partitioning_, in which different columns of a table are assigned to different physical partitions. There are not at this time any plans to introduce vertical partitioning into MySQL 5.1. For information about determining whether your MySQL Server binary supports user-defined partitioning, see *Note partitioning::. For creating partitioned tables, you can use most storage engines that are supported by your MySQL server; the MySQL partitioning engine runs in a separate layer and can interact with any of these. In MySQL 5.1, all partitions of the same partitioned table must use the same storage engine; for example, you cannot use `MyISAM' for one partition and `InnoDB' for another. However, there is nothing preventing you from using different storage engines for different partitioned tables on the same MySQL server or even in the same database. MySQL partitioning cannot be used with the `MERGE' or `CSV' storage engines. Beginning with MySQL 5.1.15, `FEDERATED' tables also cannot be partitioned (Bug#22451). Prior to MySQL 5.1.6, it was also not feasible to create a partitioned table using the `BLACKHOLE' storage engine (Bug#14524). See *Note partitioning-limitations-storage-engines::. Partitioning by `KEY' or `LINEAR KEY' is possible with *Note `NDBCLUSTER': mysql-cluster, but other types of user-defined partitioning are not supported for tables using this storage engine. In addition, an *Note `NDBCLUSTER': mysql-cluster. table that employs user-defined partitioning must have an explicit primary key, and any columns referenced in the table's partitioning expression must be part of the primary key. However, if no columns are listed in the `PARTITION BY KEY' or `PARTITION BY LINEAR KEY' clause of the *Note `CREATE TABLE': create-table. or *Note `ALTER TABLE': alter-table-partition-operations. statement used to create or modify a user-partitioned *Note `NDBCLUSTER': mysql-cluster. table, then the table is not required to have an explicit primary key. For more information, see *Note mysql-cluster-limitations-syntax::. To employ a particular storage engine for a partitioned table, it is necessary only to use the `[STORAGE] ENGINE' option just as you would for a nonpartitioned table. However, you should keep in mind that `[STORAGE] ENGINE' (and other table options) need to be listed _before_ any partitioning options are used in a *Note `CREATE TABLE': create-table. statement. This example shows how to create a table that is partitioned by hash into 6 partitions and which uses the `InnoDB' storage engine: CREATE TABLE ti (id INT, amount DECIMAL(7,2), tr_date DATE) ENGINE=INNODB PARTITION BY HASH( MONTH(tr_date) ) PARTITIONS 6; Each `PARTITION' clause can include a `[STORAGE] ENGINE' option, but in MySQL 5.1 this has no effect. *Important*: Partitioning applies to all data and indexes of a table; you cannot partition only the data and not the indexes, or _vice versa_, nor can you partition only a portion of the table. Data and indexes for each partition can be assigned to a specific directory using the `DATA DIRECTORY' and `INDEX DIRECTORY' options for the `PARTITION' clause of the *Note `CREATE TABLE': create-table. statement used to create the partitioned table. Prior to MySQL 5.1.18, these options were permitted even when the `NO_DIR_IN_CREATE' server SQL mode was in effect (Bug#24633). The `DATA DIRECTORY' and `INDEX DIRECTORY' options have no effect when defining partitions for tables using the `InnoDB' storage engine. `DATA DIRECTORY' and `INDEX DIRECTORY' are not supported for individual partitions or subpartitions on Windows. Beginning with MySQL 5.1.24, these options are ignored on Windows, except that a warning is generated (Bug#30459)- In addition, `MAX_ROWS' and `MIN_ROWS' can be used to determine the maximum and minimum numbers of rows, respectively, that can be stored in each partition. See *Note partitioning-management::, for more information on these options. Some advantages of partitioning are listed here: * Partitioning makes it possible to store more data in one table than can be held on a single disk or file system partition. * Data that loses its usefulness can often be easily removed from a partitioned table by dropping the partition (or partitions) containing only that data. Conversely, the process of adding new data can in some cases be greatly facilitated by adding one or more new partitions for storing specifically that data. * Some queries can be greatly optimized in virtue of the fact that data satisfying a given `WHERE' clause can be stored only on one or more partitions, which automatically excluding any remaining partitions from the search. Because partitions can be altered after a partitioned table has been created, you can reorganize your data to enhance frequent queries that may not have been often used when the partitioning scheme was first set up. This ability to exclude non-matching partitions (and thus any rows they contain) is often referred to as _partition pruning_, and was implemented in MySQL 5.1.6. For more information, see *Note partitioning-pruning::. Other benefits usually associated with partitioning include those in the following list. These features are not currently implemented in MySQL Partitioning, but are high on our list of priorities. * Queries involving aggregate functions such as `SUM()' and `COUNT()' can easily be parallelized. A simple example of such a query might be `SELECT salesperson_id, COUNT(orders) as order_total FROM sales GROUP BY salesperson_id;'. By `parallelized,' we mean that the query can be run simultaneously on each partition, and the final result obtained merely by summing the results obtained for all partitions. * Achieving greater query throughput in virtue of spreading data seeks over multiple disks. Be sure to check this section and chapter frequently for updates as MySQL Partitioning development continues.  File: manual.info, Node: partitioning-types, Next: partitioning-management, Prev: partitioning-overview, Up: partitioning 18.2 Partitioning Types ======================= * Menu: * partitioning-range:: `RANGE' Partitioning * partitioning-list:: `LIST' Partitioning * partitioning-hash:: `HASH' Partitioning * partitioning-key:: `KEY' Partitioning * partitioning-subpartitions:: Subpartitioning * partitioning-handling-nulls:: How MySQL Partitioning Handles `NULL' This section discusses the types of partitioning which are available in MySQL 5.1. These include the types listed here: * `RANGE' partitioning This type of partitioning assigns rows to partitions based on column values falling within a given range. See *Note partitioning-range::. * `LIST' partitioning Similar to partitioning by `RANGE', except that the partition is selected based on columns matching one of a set of discrete values. See *Note partitioning-list::. * `HASH' partitioning With this type of partitioning, a partition is selected based on the value returned by a user-defined expression that operates on column values in rows to be inserted into the table. The function may consist of any expression valid in MySQL that yields a nonnegative integer value. An extension to this type, `LINEAR HASH', is also available. See *Note partitioning-hash::. * `KEY' partitioning This type of partitioning is similar to partitioning by `HASH', except that only one or more columns to be evaluated are supplied, and the MySQL server provides its own hashing function. These columns can contain other than integer values, since the hashing function supplied by MySQL guarantees an integer result regardless of the column data type. An extension to this type, `LINEAR KEY', is also available. See *Note partitioning-key::. A very common use of database partitioning is to segregate data by date. Some database systems support explicit date partitioning, which MySQL does not implement in 5.1. However, it is not difficult in MySQL to create partitioning schemes based on *Note `DATE': datetime, *Note `TIME': time, or *Note `DATETIME': datetime. columns, or based on expressions making use of such columns. When partitioning by `KEY' or `LINEAR KEY', you can use a *Note `DATE': datetime, *Note `TIME': time, or *Note `DATETIME': datetime. column as the partitioning column without performing any modification of the column value. For example, this table creation statement is perfectly valid in MySQL: CREATE TABLE members ( firstname VARCHAR(25) NOT NULL, lastname VARCHAR(25) NOT NULL, username VARCHAR(16) NOT NULL, email VARCHAR(35), joined DATE NOT NULL ) PARTITION BY KEY(joined) PARTITIONS 6; MySQL's other partitioning types, however, require a partitioning expression that yields an integer value or `NULL'. If you wish to use date-based partitioning by `RANGE', `LIST', `HASH', or `LINEAR HASH', you can simply employ a function that operates on a *Note `DATE': datetime, *Note `TIME': time, or *Note `DATETIME': datetime. column and returns such a value, as shown here: CREATE TABLE members ( firstname VARCHAR(25) NOT NULL, lastname VARCHAR(25) NOT NULL, username VARCHAR(16) NOT NULL, email VARCHAR(35), joined DATE NOT NULL ) PARTITION BY RANGE( YEAR(joined) ) ( PARTITION p0 VALUES LESS THAN (1960), PARTITION p1 VALUES LESS THAN (1970), PARTITION p2 VALUES LESS THAN (1980), PARTITION p3 VALUES LESS THAN (1990), PARTITION p4 VALUES LESS THAN MAXVALUE ); Additional examples of partitioning using dates may be found in the following sections of this chapter: * *Note partitioning-range:: * *Note partitioning-hash:: * *Note partitioning-linear-hash:: For more complex examples of date-based partitioning, see the following sections: * *Note partitioning-pruning:: * *Note partitioning-subpartitions:: MySQL partitioning is optimized for use with the `TO_DAYS()' and `YEAR()' functions. However, you can use other date and time functions that return an integer or `NULL', such as `WEEKDAY()', `DAYOFYEAR()', or `MONTH()'. See *Note date-and-time-functions::, for more information about such functions. It is important to remember--regardless of the type of partitioning that you use--that partitions are always numbered automatically and in sequence when created, starting with `0'. When a new row is inserted into a partitioned table, it is these partition numbers that are used in identifying the correct partition. For example, if your table uses 4 partitions, these partitions are numbered `0', `1', `2', and `3'. For the `RANGE' and `LIST' partitioning types, it is necessary to ensure that there is a partition defined for each partition number. For `HASH' partitioning, the user function employed must return an integer value greater than `0'. For `KEY' partitioning, this issue is taken care of automatically by the hashing function which the MySQL server employs internally. Names of partitions generally follow the rules governing other MySQL identifiers, such as those for tables and databases. However, you should note that partition names are not case-sensitive. For example, the following *Note `CREATE TABLE': create-table. statement fails as shown: mysql> CREATE TABLE t2 (val INT) -> PARTITION BY LIST(val)( -> PARTITION mypart VALUES IN (1,3,5), -> PARTITION MyPart VALUES IN (2,4,6) -> ); ERROR 1488 (HY000): Duplicate partition name mypart Failure occurs because MySQL sees no difference between the partition names `mypart' and `MyPart'. When you specify the number of partitions for the table, this must be expressed as a positive, nonzero integer literal with no leading zeros, and may not be an expression such as `0.8E+01' or `6-2', even if it evaluates to an integer value. (Beginning with MySQL 5.1.12, decimal fractions are no longer truncated, but instead are prohibited entirely.) In the sections that follow, we do not necessarily provide all possible forms for the syntax that can be used for creating each partition type; this information may be found in *Note create-table::.  File: manual.info, Node: partitioning-range, Next: partitioning-list, Prev: partitioning-types, Up: partitioning-types 18.2.1 `RANGE' Partitioning --------------------------- A table that is partitioned by range is partitioned in such a way that each partition contains rows for which the partitioning expression value lies within a given range. Ranges should be contiguous but not overlapping, and are defined using the `VALUES LESS THAN' operator. For the next few examples, suppose that you are creating a table such as the following to hold personnel records for a chain of 20 video stores, numbered 1 through 20: CREATE TABLE employees ( id INT NOT NULL, fname VARCHAR(30), lname VARCHAR(30), hired DATE NOT NULL DEFAULT '1970-01-01', separated DATE NOT NULL DEFAULT '9999-12-31', job_code INT NOT NULL, store_id INT NOT NULL ); This table can be partitioned by range in a number of ways, depending on your needs. One way would be to use the `store_id' column. For instance, you might decide to partition the table 4 ways by adding a `PARTITION BY RANGE' clause as shown here: CREATE TABLE employees ( id INT NOT NULL, fname VARCHAR(30), lname VARCHAR(30), hired DATE NOT NULL DEFAULT '1970-01-01', separated DATE NOT NULL DEFAULT '9999-12-31', job_code INT NOT NULL, store_id INT NOT NULL ) PARTITION BY RANGE (store_id) ( PARTITION p0 VALUES LESS THAN (6), PARTITION p1 VALUES LESS THAN (11), PARTITION p2 VALUES LESS THAN (16), PARTITION p3 VALUES LESS THAN (21) ); In this partitioning scheme, all rows corresponding to employees working at stores 1 through 5 are stored in partition `p0', to those employed at stores 6 through 10 are stored in partition `p1', and so on. Note that each partition is defined in order, from lowest to highest. This is a requirement of the `PARTITION BY RANGE' syntax; you can think of it as being analogous to a series of `if ... elseif ...' statements in C or Java in this regard. It is easy to determine that a new row containing the data `(72, 'Michael', 'Widenius', '1998-06-25', NULL, 13)' is inserted into partition `p2', but what happens when your chain adds a 21^st store? Under this scheme, there is no rule that covers a row whose `store_id' is greater than 20, so an error results because the server does not know where to place it. You can keep this from occurring by using a `catchall' `VALUES LESS THAN' clause in the *Note `CREATE TABLE': create-table. statement that provides for all values greater than the highest value explicitly named: CREATE TABLE employees ( id INT NOT NULL, fname VARCHAR(30), lname VARCHAR(30), hired DATE NOT NULL DEFAULT '1970-01-01', separated DATE NOT NULL DEFAULT '9999-12-31', job_code INT NOT NULL, store_id INT NOT NULL ) PARTITION BY RANGE (store_id) ( PARTITION p0 VALUES LESS THAN (6), PARTITION p1 VALUES LESS THAN (11), PARTITION p2 VALUES LESS THAN (16), _PARTITION p3 VALUES LESS THAN MAXVALUE_ ); *Note*: Another way to avoid an error when no matching value is found is to use the `IGNORE' keyword as part of the *Note `INSERT': insert. statement. For an example, see *Note partitioning-list::. Also see *Note insert::, for general information about `IGNORE'. `MAXVALUE' represents an integer value that is always greater than the largest possible integer value (in mathematical language, it serves as a _least upper bound_). Now, any rows whose `store_id' column value is greater than or equal to 16 (the highest value defined) are stored in partition `p3'. At some point in the future--when the number of stores has increased to 25, 30, or more--you can use an *Note `ALTER TABLE': alter-table-partition-operations. statement to add new partitions for stores 21-25, 26-30, and so on (see *Note partitioning-management::, for details of how to do this). In much the same fashion, you could partition the table based on employee job codes--that is, based on ranges of `job_code' column values. For example--assuming that two-digit job codes are used for regular (in-store) workers, three-digit codes are used for office and support personnel, and four-digit codes are used for management positions--you could create the partitioned table using the following statement: CREATE TABLE employees ( id INT NOT NULL, fname VARCHAR(30), lname VARCHAR(30), hired DATE NOT NULL DEFAULT '1970-01-01', separated DATE NOT NULL DEFAULT '9999-12-31', job_code INT NOT NULL, store_id INT NOT NULL ) PARTITION BY RANGE (job_code) ( PARTITION p0 VALUES LESS THAN (100), PARTITION p1 VALUES LESS THAN (1000), PARTITION p2 VALUES LESS THAN (10000) ); In this instance, all rows relating to in-store workers would be stored in partition `p0', those relating to office and support staff in `p1', and those relating to managers in partition `p2'. It is also possible to use an expression in `VALUES LESS THAN' clauses. However, MySQL must be able to evaluate the expression's return value as part of a `LESS THAN' (`<') comparison. Rather than splitting up the table data according to store number, you can use an expression based on one of the two *Note `DATE': datetime. columns instead. For example, let us suppose that you wish to partition based on the year that each employee left the company; that is, the value of `YEAR(separated)'. An example of a *Note `CREATE TABLE': create-table. statement that implements such a partitioning scheme is shown here: CREATE TABLE employees ( id INT NOT NULL, fname VARCHAR(30), lname VARCHAR(30), hired DATE NOT NULL DEFAULT '1970-01-01', separated DATE NOT NULL DEFAULT '9999-12-31', job_code INT, store_id INT ) PARTITION BY RANGE ( YEAR(separated) ) ( PARTITION p0 VALUES LESS THAN (1991), PARTITION p1 VALUES LESS THAN (1996), PARTITION p2 VALUES LESS THAN (2001), PARTITION p3 VALUES LESS THAN MAXVALUE ); In this scheme, for all employees who left before 1991, the rows are stored in partition `p0'; for those who left in the years 1991 through 1995, in `p1'; for those who left in the years 1996 through 2000, in `p2'; and for any workers who left after the year 2000, in `p3'. Beginning with MySQL 5.1.43, it is also possible to partition a table by `RANGE' based on the value of a *Note `TIMESTAMP': datetime. column, using the `UNIX_TIMESTAMP()' function, as shown in this example: CREATE TABLE quarterly_report_status ( report_id INT NOT NULL, report_status VARCHAR(20) NOT NULL, report_updated TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP ) PARTITION BY RANGE ( UNIX_TIMESTAMP(report_updated) ) ( PARTITION p0 VALUES LESS THAN ( UNIX_TIMESTAMP('2008-01-01 00:00:00') ), PARTITION p1 VALUES LESS THAN ( UNIX_TIMESTAMP('2008-04-01 00:00:00') ), PARTITION p2 VALUES LESS THAN ( UNIX_TIMESTAMP('2008-07-01 00:00:00') ), PARTITION p3 VALUES LESS THAN ( UNIX_TIMESTAMP('2008-10-01 00:00:00') ), PARTITION p4 VALUES LESS THAN ( UNIX_TIMESTAMP('2009-01-01 00:00:00') ), PARTITION p5 VALUES LESS THAN ( UNIX_TIMESTAMP('2009-04-01 00:00:00') ), PARTITION p6 VALUES LESS THAN ( UNIX_TIMESTAMP('2009-07-01 00:00:00') ), PARTITION p7 VALUES LESS THAN ( UNIX_TIMESTAMP('2009-10-01 00:00:00') ), PARTITION p8 VALUES LESS THAN ( UNIX_TIMESTAMP('2010-01-01 00:00:00') ), PARTITION p9 VALUES LESS THAN (MAXVALUE) ); Also beginning with MySQL 5.1.43, any other expressions involving *Note `TIMESTAMP': datetime. values are not permitted. (See Bug#42849.) *Note*: It is also possible in MySQL 5.1.43 and later to use `UNIX_TIMESTAMP(TIMESTAMP_COLUMN)' as a partitioning expression for tables that are partitioned by `LIST'. However, it is usually not practical to do so. Range partitioning is particularly useful when one or more of the following conditions is true: * You want or need to delete `old' data. If you are using the partitioning scheme shown immediately above, you can simply use `ALTER TABLE employees DROP PARTITION p0;' to delete all rows relating to employees who stopped working for the firm prior to 1991. (See *Note alter-table::, and *Note partitioning-management::, for more information.) For a table with a great many rows, this can be much more efficient than running a *Note `DELETE': delete. query such as `DELETE FROM employees WHERE YEAR(separated) <= 1990;'. * You want to use a column containing date or time values, or containing values arising from some other series. * You frequently run queries that depend directly on the column used for partitioning the table. For example, when executing a query such as *Note `EXPLAIN PARTITIONS SELECT COUNT(*) FROM employees WHERE separated BETWEEN '2000-01-01' AND '2000-12-31' GROUP BY store_id;': explain, MySQL can quickly determine that only partition `p2' needs to be scanned because the remaining partitions cannot contain any records satisfying the `WHERE' clause. See *Note partitioning-pruning::, for more information about how this is accomplished.  File: manual.info, Node: partitioning-list, Next: partitioning-hash, Prev: partitioning-range, Up: partitioning-types 18.2.2 `LIST' Partitioning -------------------------- List partitioning in MySQL is similar to range partitioning in many ways. As in partitioning by `RANGE', each partition must be explicitly defined. The chief difference between the two types of partitioning is that, in list partitioning, each partition is defined and selected based on the membership of a column value in one of a set of value lists, rather than in one of a set of contiguous ranges of values. This is done by using `PARTITION BY LIST(EXPR)' where EXPR is a column value or an expression based on a column value and returning an integer value, and then defining each partition by means of a `VALUES IN (VALUE_LIST)', where VALUE_LIST is a comma-separated list of integers. *Note*: In MySQL 5.1, it is possible to match against only a list of integers (and possibly `NULL'--see *Note partitioning-handling-nulls::) when partitioning by `LIST'. Unlike the case with partitions defined by range, list partitions do not need to be declared in any particular order. For more detailed syntactical information, see *Note create-table::. For the examples that follow, we assume that the basic definition of the table to be partitioned is provided by the *Note `CREATE TABLE': create-table. statement shown here: CREATE TABLE employees ( id INT NOT NULL, fname VARCHAR(30), lname VARCHAR(30), hired DATE NOT NULL DEFAULT '1970-01-01', separated DATE NOT NULL DEFAULT '9999-12-31', job_code INT, store_id INT ); (This is the same table used as a basis for the examples in *Note partitioning-range::.) Suppose that there are 20 video stores distributed among 4 franchises as shown in the following table. Region Store ID Numbers North 3, 5, 6, 9, 17 East 1, 2, 10, 11, 19, 20 West 4, 12, 13, 14, 18 Central 7, 8, 15, 16 To partition this table in such a way that rows for stores belonging to the same region are stored in the same partition, you could use the *Note `CREATE TABLE': create-table. statement shown here: CREATE TABLE employees ( id INT NOT NULL, fname VARCHAR(30), lname VARCHAR(30), hired DATE NOT NULL DEFAULT '1970-01-01', separated DATE NOT NULL DEFAULT '9999-12-31', job_code INT, store_id INT ) PARTITION BY LIST(store_id) ( PARTITION pNorth VALUES IN (3,5,6,9,17), PARTITION pEast VALUES IN (1,2,10,11,19,20), PARTITION pWest VALUES IN (4,12,13,14,18), PARTITION pCentral VALUES IN (7,8,15,16) ); This makes it easy to add or drop employee records relating to specific regions to or from the table. For instance, suppose that all stores in the West region are sold to another company. All rows relating to employees working at stores in that region can be deleted with an `ALTER TABLE employees DROP PARTITION pWest' statement, which can be executed much more efficiently than the equivalent *Note `DELETE': delete. statement (`DELETE FROM employees WHERE store_id IN (4,12,13,14,18)'). However, the *Note `ALTER TABLE ... DROP PARTITION': alter-table. statement also removes the partition itself from the definition for the table, and you must execute an *Note `ALTER TABLE ... ADD PARTITION': alter-table. statement to restore the table's original partitioning scheme. (This problem is resolved in MySQL 5.5, which adds the *Note `ALTER TABLE ... TRUNCATE PARTITION': alter-table. statement for removing all rows from a given partition without affecting the table definition.) As with `RANGE' partitioning, it is possible to combine `LIST' partitioning with partitioning by hash or key to produce a composite partitioning (subpartitioning). See *Note partitioning-subpartitions::. Unlike the case with `RANGE' partitioning, there is no `catch-all' such as `MAXVALUE'; all expected values for the partitioning expression should be covered in `PARTITION ... VALUES IN (...)' clauses. An *Note `INSERT': insert. statement containing an unmatched partitioning column value fails with an error, as shown in this example: mysql> CREATE TABLE h2 ( -> c1 INT, -> c2 INT -> ) -> PARTITION BY LIST(c1) ( -> PARTITION p0 VALUES IN (1, 4, 7), -> PARTITION p1 VALUES IN (2, 5, 8) -> ); Query OK, 0 rows affected (0.11 sec) mysql> INSERT INTO h2 VALUES (3, 5); `ERROR 1525 (HY000): Table has no partition for value 3' When inserting multiple rows using a single *Note `INSERT': insert. statement, any rows coming before the row containing the unmatched value are inserted, but any coming after it are not: mysql> SELECT * FROM h2; Empty set (0.00 sec) mysql> INSERT INTO h2 VALUES (4, 7), (3, 5), (6, 0); `ERROR 1525 (HY000): Table has no partition for value 3' mysql> SELECT * FROM h2; +------+------+ | c1 | c2 | +------+------+ | 4 | 7 | +------+------+ 1 row in set (0.00 sec) You can cause this type of error to be ignored by using the `IGNORE' keyword. If you do so, rows containing unmatched partitioning column values are not inserted, but any rows with matching values _are_ inserted, and no errors are reported: mysql> TRUNCATE h2; Query OK, 1 row affected (0.00 sec) mysql> SELECT * FROM h2; Empty set (0.00 sec) mysql> INSERT IGNORE INTO h2 VALUES (2, 5), (6, 10), (7, 5), (3, 1), (1, 9); Query OK, 3 rows affected (0.00 sec) Records: 5 Duplicates: 2 Warnings: 0 mysql> SELECT * FROM h2; +------+------+ | c1 | c2 | +------+------+ | 7 | 5 | | 1 | 9 | | 2 | 5 | +------+------+ 3 rows in set (0.00 sec)  File: manual.info, Node: partitioning-hash, Next: partitioning-key, Prev: partitioning-list, Up: partitioning-types 18.2.3 `HASH' Partitioning -------------------------- * Menu: * partitioning-linear-hash:: `LINEAR HASH' Partitioning Partitioning by `HASH' is used primarily to ensure an even distribution of data among a predetermined number of partitions. With range or list partitioning, you must specify explicitly into which partition a given column value or set of column values is to be stored; with hash partitioning, MySQL takes care of this for you, and you need only specify a column value or expression based on a column value to be hashed and the number of partitions into which the partitioned table is to be divided. To partition a table using `HASH' partitioning, it is necessary to append to the *Note `CREATE TABLE': create-table. statement a `PARTITION BY HASH (EXPR)' clause, where EXPR is an expression that returns an integer. This can simply be the name of a column whose type is one of MySQL's integer types. In addition, you will most likely want to follow this with a `PARTITIONS NUM' clause, where NUM is a positive integer representing the number of partitions into which the table is to be divided. For example, the following statement creates a table that uses hashing on the `store_id' column and is divided into 4 partitions: CREATE TABLE employees ( id INT NOT NULL, fname VARCHAR(30), lname VARCHAR(30), hired DATE NOT NULL DEFAULT '1970-01-01', separated DATE NOT NULL DEFAULT '9999-12-31', job_code INT, store_id INT ) PARTITION BY HASH(store_id) PARTITIONS 4; If you do not include a `PARTITIONS' clause, the number of partitions defaults to `1'. Using the `PARTITIONS' keyword without a number following it results in a syntax error. You can also use an SQL expression that returns an integer for EXPR. For instance, you might want to partition based on the year in which an employee was hired. This can be done as shown here: CREATE TABLE employees ( id INT NOT NULL, fname VARCHAR(30), lname VARCHAR(30), hired DATE NOT NULL DEFAULT '1970-01-01', separated DATE NOT NULL DEFAULT '9999-12-31', job_code INT, store_id INT ) PARTITION BY HASH( YEAR(hired) ) PARTITIONS 4; EXPR must return a nonconstant, nonrandom integer value (in other words, it should be varying but deterministic), and must not contain any prohibited constructs as described in *Note partitioning-limitations::. You should also keep in mind that this expression is evaluated each time a row is inserted or updated (or possibly deleted); this means that very complex expressions may give rise to performance issues, particularly when performing operations (such as batch inserts) that affect a great many rows at one time. The most efficient hashing function is one which operates upon a single table column and whose value increases or decreases consistently with the column value, as this allows for `pruning' on ranges of partitions. That is, the more closely that the expression varies with the value of the column on which it is based, the more efficiently MySQL can use the expression for hash partitioning. For example, where `date_col' is a column of type *Note `DATE': datetime, then the expression `TO_DAYS(date_col)' is said to vary directly with the value of `date_col', because for every change in the value of `date_col', the value of the expression changes in a consistent manner. The variance of the expression `YEAR(date_col)' with respect to `date_col' is not quite as direct as that of `TO_DAYS(date_col)', because not every possible change in `date_col' produces an equivalent change in `YEAR(date_col)'. Even so, `YEAR(date_col)' is a good candidate for a hashing function, because it varies directly with a portion of `date_col' and there is no possible change in `date_col' that produces a disproportionate change in `YEAR(date_col)'. By way of contrast, suppose that you have a column named `int_col' whose type is *Note `INT': numeric-types. Now consider the expression `POW(5-int_col,3) + 6'. This would be a poor choice for a hashing function because a change in the value of `int_col' is not guaranteed to produce a proportional change in the value of the expression. Changing the value of `int_col' by a given amount can produce by widely different changes in the value of the expression. For example, changing `int_col' from `5' to `6' produces a change of `-1' in the value of the expression, but changing the value of `int_col' from `6' to `7' produces a change of `-7' in the expression value. In other words, the more closely the graph of the column value _versus_ the value of the expression follows a straight line as traced by the equation `y=Cx' where C is some nonzero constant, the better the expression is suited to hashing. This has to do with the fact that the more nonlinear an expression is, the more uneven the distribution of data among the partitions it tends to produce. In theory, pruning is also possible for expressions involving more than one column value, but determining which of such expressions are suitable can be quite difficult and time-consuming. For this reason, the use of hashing expressions involving multiple columns is not particularly recommended. When `PARTITION BY HASH' is used, MySQL determines which partition of NUM partitions to use based on the modulus of the result of the user function. In other words, for an expression EXPR, the partition in which the record is stored is partition number N, where `N = MOD(EXPR, NUM)'. Suppose that table `t1' is defined as follows, so that it has 4 partitions: CREATE TABLE t1 (col1 INT, col2 CHAR(5), col3 DATE) PARTITION BY HASH( YEAR(col3) ) PARTITIONS 4; If you insert a record into `t1' whose `col3' value is `'2005-09-15'', then the partition in which it is stored is determined as follows: MOD(YEAR('2005-09-01'),4) = MOD(2005,4) = 1 MySQL 5.1 also supports a variant of `HASH' partitioning known as _linear hashing_ which employs a more complex algorithm for determining the placement of new rows inserted into the partitioned table. See *Note partitioning-linear-hash::, for a description of this algorithm. The user function is evaluated each time a record is inserted or updated. It may also--depending on the circumstances--be evaluated when records are deleted. *Note*: If a table to be partitioned has a `UNIQUE' key, then any columns supplied as arguments to the `HASH' user function or to the `KEY''s COLUMN_LIST must be part of that key.  File: manual.info, Node: partitioning-linear-hash, Prev: partitioning-hash, Up: partitioning-hash 18.2.3.1 `LINEAR HASH' Partitioning ................................... MySQL also supports linear hashing, which differs from regular hashing in that linear hashing utilizes a linear powers-of-two algorithm whereas regular hashing employs the modulus of the hashing function's value. Syntactically, the only difference between linear-hash partitioning and regular hashing is the addition of the `LINEAR' keyword in the `PARTITION BY' clause, as shown here: CREATE TABLE employees ( id INT NOT NULL, fname VARCHAR(30), lname VARCHAR(30), hired DATE NOT NULL DEFAULT '1970-01-01', separated DATE NOT NULL DEFAULT '9999-12-31', job_code INT, store_id INT ) PARTITION BY LINEAR HASH( YEAR(hired) ) PARTITIONS 4; Given an expression EXPR, the partition in which the record is stored when linear hashing is used is partition number N from among NUM partitions, where N is derived according to the following algorithm: 1. Find the next power of 2 greater than NUM. We call this value V; it can be calculated as: V = POWER(2, CEILING(LOG(2, NUM))) (Suppose that NUM is 13. Then `LOG(2,13)' is 3.7004397181411. `CEILING(3.7004397181411)' is 4, and V = `POWER(2,4)', which is 16.) 2. Set N = F(COLUMN_LIST) & (V - 1). 3. While N >= NUM: * Set V = CEIL(V / 2) * Set N = N & (V - 1) Suppose that the table `t1', using linear hash partitioning and having 6 partitions, is created using this statement: CREATE TABLE t1 (col1 INT, col2 CHAR(5), col3 DATE) PARTITION BY LINEAR HASH( YEAR(col3) ) PARTITIONS 6; Now assume that you want to insert two records into `t1' having the `col3' column values `'2003-04-14'' and `'1998-10-19''. The partition number for the first of these is determined as follows: V = POWER(2, CEILING( LOG(2,6) )) = 8 N = YEAR('2003-04-14') & (8 - 1) = 2003 & 7 = 3 (_3 >= 6 is FALSE: record stored in partition #3_) The number of the partition where the second record is stored is calculated as shown here: V = 8 N = YEAR('1998-10-19') & (8-1) = 1998 & 7 = 6 (_6 >= 6 is TRUE: additional step required_) N = 6 & CEILING(8 / 2) = 6 & 3 = 2 (_2 >= 6 is FALSE: record stored in partition #2_) The advantage in partitioning by linear hash is that the adding, dropping, merging, and splitting of partitions is made much faster, which can be beneficial when dealing with tables containing extremely large amounts (terabytes) of data. The disadvantage is that data is less likely to be evenly distributed between partitions as compared with the distribution obtained using regular hash partitioning.  File: manual.info, Node: partitioning-key, Next: partitioning-subpartitions, Prev: partitioning-hash, Up: partitioning-types 18.2.4 `KEY' Partitioning ------------------------- Partitioning by key is similar to partitioning by hash, except that where hash partitioning employs a user-defined expression, the hashing function for key partitioning is supplied by the MySQL server. MySQL Cluster uses `MD5()' for this purpose; for tables using other storage engines, the server employs its own internal hashing function which is based on the same algorithm as `PASSWORD()'. The syntax rules for `CREATE TABLE ... PARTITION BY KEY' are similar to those for creating a table that is partitioned by hash. The major differences are listed here: * `KEY' is used rather than `HASH'. * `KEY' takes only a list of one or more column names. Beginning with MySQL 5.1.5, the column or columns used as the partitioning key must comprise part or all of the table's primary key, if the table has one. Beginning with MySQL 5.1.6, `KEY' takes a list of zero or more column names. Where no column name is specified as the partitioning key, the table's primary key is used, if there is one. For example, the following *Note `CREATE TABLE': create-table. statement is valid in MySQL 5.1.6 or later: CREATE TABLE k1 ( id INT NOT NULL PRIMARY KEY, name VARCHAR(20) ) PARTITION BY KEY() PARTITIONS 2; If there is no primary key but there is a unique key, then the unique key is used for the partitioning key: CREATE TABLE k1 ( id INT NOT NULL, name VARCHAR(20), UNIQUE KEY (id) ) PARTITION BY KEY() PARTITIONS 2; However, if the unique key column were not defined as `NOT NULL', then the previous statement would fail. In both of these cases, the partitioning key is the `id' column, even though it is not shown in the output of *Note `SHOW CREATE TABLE': show-create-table. or in the `PARTITION_EXPRESSION' column of the *Note `INFORMATION_SCHEMA.PARTITIONS': partitions-table. table. Unlike the case with other partitioning types, columns used for partitioning by `KEY' are not restricted to integer or `NULL' values. For example, the following *Note `CREATE TABLE': create-table. statement is valid: CREATE TABLE tm1 ( s1 CHAR(32) PRIMARY KEY ) PARTITION BY KEY(s1) PARTITIONS 10; The preceding statement would _not_ be valid, were a different partitioning type to be specified. (In this case, simply using `PARTITION BY KEY()' would also be valid and have the same effect as `PARTITION BY KEY(s1)', since `s1' is the table's primary key.) For additional information about this issue, see *Note partitioning-limitations::. *Note*: Also beginning with MySQL 5.1.6, tables using the *Note `NDBCLUSTER': mysql-cluster. storage engine are implicitly partitioned by `KEY', again using the table's primary key as the partitioning key. In the event that the MySQL Cluster table has no explicit primary key, the `hidden' primary key generated by the *Note `NDBCLUSTER': mysql-cluster. storage engine for each MySQL Cluster table is used as the partitioning key. Beginning with MySQL Cluster NDB 6.2.18, MySQL Cluster NDB 6.3.25, and MySQL Cluster NDB 7.0.6, if you define an explicit partitioning scheme for an *Note `NDBCLUSTER': mysql-cluster. table, the table must have an explicit primary key, and any columns used in the partitioning expression must be part of this key. However, if the table uses an `empty' partitioning expression--that is, `PARTITION BY KEY()' with no column references--then no explicit primary key is required. You can observe this partitioning using the *Note `ndb_desc': mysql-cluster-programs-ndb-desc. utility (with the `-p' option). *Important*: For a key-partitioned table using any MySQL storage engine other than *Note `NDBCLUSTER': mysql-cluster, you cannot execute an `ALTER TABLE DROP PRIMARY KEY', as doing so generates the error `ERROR 1466 (HY000): Field in list of fields for partition function not found in table'. This is not an issue for MySQL Cluster tables which are partitioned by `KEY'; in such cases, the table is reorganized using the `hidden' primary key as the table's new partitioning key. See *Note mysql-cluster::. It is also possible to partition a table by linear key. Here is a simple example: CREATE TABLE tk ( col1 INT NOT NULL, col2 CHAR(5), col3 DATE ) PARTITION BY LINEAR KEY (col1) PARTITIONS 3; Using `LINEAR' has the same effect on `KEY' partitioning as it does on `HASH' partitioning, with the partition number being derived using a powers-of-two algorithm rather than modulo arithmetic. See *Note partitioning-linear-hash::, for a description of this algorithm and its implications.  File: manual.info, Node: partitioning-subpartitions, Next: partitioning-handling-nulls, Prev: partitioning-key, Up: partitioning-types 18.2.5 Subpartitioning ---------------------- Subpartitioning--also known as _composite partitioning_--is the further division of each partition in a partitioned table. Consider the following *Note `CREATE TABLE': create-table. statement: CREATE TABLE ts (id INT, purchased DATE) PARTITION BY RANGE( YEAR(purchased) ) SUBPARTITION BY HASH( TO_DAYS(purchased) ) SUBPARTITIONS 2 ( PARTITION p0 VALUES LESS THAN (1990), PARTITION p1 VALUES LESS THAN (2000), PARTITION p2 VALUES LESS THAN MAXVALUE ); Table `ts' has 3 `RANGE' partitions. Each of these partitions--`p0', `p1', and `p2'--is further divided into 2 subpartitions. In effect, the entire table is divided into `3 * 2 = 6' partitions. However, due to the action of the `PARTITION BY RANGE' clause, the first 2 of these store only those records with a value less than 1990 in the `purchased' column. In MySQL 5.1, it is possible to subpartition tables that are partitioned by `RANGE' or `LIST'. Subpartitions may use either `HASH' or `KEY' partitioning. This is also known as _composite partitioning_. *Note*: `SUBPARTITION BY HASH' and `SUBPARTITION BY KEY' generally follow the same syntax rules as `PARTITION BY HASH' and `PARTITION BY KEY', respectively. An exception to this is that `SUBPARTITION BY KEY' (unlike `PARTITION BY KEY') does not currently support a default column, so the column used for this purpose must be specified, even if the table has an explicit primary key. This is a known issue which we are working to address; see *Note partitioning-limitations-subpartitions::, for more information and an example. It is also possible to define subpartitions explicitly using `SUBPARTITION' clauses to specify options for individual subpartitions. For example, a more verbose fashion of creating the same table `ts' as shown in the previous example would be: CREATE TABLE ts (id INT, purchased DATE) PARTITION BY RANGE( YEAR(purchased) ) SUBPARTITION BY HASH( TO_DAYS(purchased) ) ( PARTITION p0 VALUES LESS THAN (1990) ( SUBPARTITION s0, SUBPARTITION s1 ), PARTITION p1 VALUES LESS THAN (2000) ( SUBPARTITION s2, SUBPARTITION s3 ), PARTITION p2 VALUES LESS THAN MAXVALUE ( SUBPARTITION s4, SUBPARTITION s5 ) ); Some syntactical items of note are listed here: * Each partition must have the same number of subpartitions. * If you explicitly define any subpartitions using `SUBPARTITION' on any partition of a partitioned table, you must define them all. In other words, the following statement will fail: CREATE TABLE ts (id INT, purchased DATE) PARTITION BY RANGE( YEAR(purchased) ) SUBPARTITION BY HASH( TO_DAYS(purchased) ) ( PARTITION p0 VALUES LESS THAN (1990) ( SUBPARTITION s0, SUBPARTITION s1 ), PARTITION p1 VALUES LESS THAN (2000), PARTITION p2 VALUES LESS THAN MAXVALUE ( SUBPARTITION s2, SUBPARTITION s3 ) ); This statement would still fail even if it included a `SUBPARTITIONS 2' clause. * Each `SUBPARTITION' clause must include (at a minimum) a name for the subpartition. Otherwise, you may set any desired option for the subpartition or allow it to assume its default setting for that option. * In MySQL 5.1.7 and earlier, names of subpartitions were required to be unique within each partition, but did not have to be unique within the table as a whole. Beginning with MySQL 5.1.8, subpartition names must be unique across the entire table. For example, the following *Note `CREATE TABLE': create-table. statement is valid in MySQL 5.1.8 and later: CREATE TABLE ts (id INT, purchased DATE) PARTITION BY RANGE( YEAR(purchased) ) SUBPARTITION BY HASH( TO_DAYS(purchased) ) ( PARTITION p0 VALUES LESS THAN (1990) ( SUBPARTITION s0, SUBPARTITION s1 ), PARTITION p1 VALUES LESS THAN (2000) ( SUBPARTITION s2, SUBPARTITION s3 ), PARTITION p2 VALUES LESS THAN MAXVALUE ( SUBPARTITION s4, SUBPARTITION s5 ) ); (The previous statement is also valid for versions of MySQL prior to 5.1.8.) Subpartitions can be used with especially large tables to distribute data and indexes across many disks. Suppose that you have 6 disks mounted as `/disk0', `/disk1', `/disk2', and so on. Now consider the following example: CREATE TABLE ts (id INT, purchased DATE) PARTITION BY RANGE( YEAR(purchased) ) SUBPARTITION BY HASH( TO_DAYS(purchased) ) ( PARTITION p0 VALUES LESS THAN (1990) ( SUBPARTITION s0 DATA DIRECTORY = '/disk0/data' INDEX DIRECTORY = '/disk0/idx', SUBPARTITION s1 DATA DIRECTORY = '/disk1/data' INDEX DIRECTORY = '/disk1/idx' ), PARTITION p1 VALUES LESS THAN (2000) ( SUBPARTITION s2 DATA DIRECTORY = '/disk2/data' INDEX DIRECTORY = '/disk2/idx', SUBPARTITION s3 DATA DIRECTORY = '/disk3/data' INDEX DIRECTORY = '/disk3/idx' ), PARTITION p2 VALUES LESS THAN MAXVALUE ( SUBPARTITION s4 DATA DIRECTORY = '/disk4/data' INDEX DIRECTORY = '/disk4/idx', SUBPARTITION s5 DATA DIRECTORY = '/disk5/data' INDEX DIRECTORY = '/disk5/idx' ) ); In this case, a separate disk is used for the data and for the indexes of each `RANGE'. Many other variations are possible; another example might be: CREATE TABLE ts (id INT, purchased DATE) PARTITION BY RANGE(YEAR(purchased)) SUBPARTITION BY HASH( TO_DAYS(purchased) ) ( PARTITION p0 VALUES LESS THAN (1990) ( SUBPARTITION s0a DATA DIRECTORY = '/disk0' INDEX DIRECTORY = '/disk1', SUBPARTITION s0b DATA DIRECTORY = '/disk2' INDEX DIRECTORY = '/disk3' ), PARTITION p1 VALUES LESS THAN (2000) ( SUBPARTITION s1a DATA DIRECTORY = '/disk4/data' INDEX DIRECTORY = '/disk4/idx', SUBPARTITION s1b DATA DIRECTORY = '/disk5/data' INDEX DIRECTORY = '/disk5/idx' ), PARTITION p2 VALUES LESS THAN MAXVALUE ( SUBPARTITION s2a, SUBPARTITION s2b ) ); Here, the storage is as follows: * Rows with `purchased' dates from before 1990 take up a vast amount of space, so are split up 4 ways, with a separate disk dedicated to the data and to the indexes for each of the two subpartitions (`s0a' and `s0b') making up partition `p0'. In other words: * The data for subpartition `s0a' is stored on `/disk0'. * The indexes for subpartition `s0a' are stored on `/disk1'. * The data for subpartition `s0b' is stored on `/disk2'. * The indexes for subpartition `s0b' are stored on `/disk3'. * Rows containing dates ranging from 1990 to 1999 (partition `p1') do not require as much room as those from before 1990. These are split between 2 disks (`/disk4' and `/disk5') rather than 4 disks as with the legacy records stored in `p0': * Data and indexes belonging to `p1''s first subpartition (`s1a') are stored on `/disk4'--the data in `/disk4/data', and the indexes in `/disk4/idx'. * Data and indexes belonging to `p1''s second subpartition (`s1b') are stored on `/disk5'--the data in `/disk5/data', and the indexes in `/disk5/idx'. * Rows reflecting dates from the year 2000 to the present (partition `p2') do not take up as much space as required by either of the two previous ranges. Currently, it is sufficient to store all of these in the default location. In future, when the number of purchases for the decade beginning with the year 2000 grows to a point where the default location no longer provides sufficient space, the corresponding rows can be moved using an `ALTER TABLE ... REORGANIZE PARTITION' statement. See *Note partitioning-management::, for an explanation of how this can be done. Beginning with MySQL 5.1.18, the `DATA DIRECTORY' and `INDEX DIRECTORY' options are not permitted in partition definitions when the `NO_DIR_IN_CREATE' server SQL mode is in effect. However, this not true when defining subpartitions; this is a known issue which is fixed in MySQL 5.5 (Bug#42954).  File: manual.info, Node: partitioning-handling-nulls, Prev: partitioning-subpartitions, Up: partitioning-types 18.2.6 How MySQL Partitioning Handles `NULL' -------------------------------------------- Partitioning in MySQL does nothing to disallow `NULL' as the value of a partitioning expression, whether it is a column value or the value of a user-supplied expression. Even though it is permitted to use `NULL' as the value of an expression that must otherwise yield an integer, it is important to keep in mind that `NULL' is not a number. Beginning with MySQL 5.1.8, the partitioning implementation treats `NULL' as being less than any non-`NULL' value, just as `ORDER BY' does. This means that treatment of `NULL' varies between partitioning of different types, and may produce behavior which you do not expect if you are not prepared for it. This being the case, we discuss in this section how each MySQL partitioning type handles `NULL' values when determining the partition in which a row should be stored, and provide examples for each. Handling of `NULL' with `RANGE' partitioning If you insert a row into a table partitioned by `RANGE' such that the column value used to determine the partition is `NULL', the row is inserted into the lowest partition. Consider these two tables in a database named `p', created as follows: mysql> CREATE TABLE t1 ( -> c1 INT, -> c2 VARCHAR(20) -> ) -> PARTITION BY RANGE(c1) ( -> PARTITION p0 VALUES LESS THAN (0), -> PARTITION p1 VALUES LESS THAN (10), -> PARTITION p2 VALUES LESS THAN MAXVALUE -> ); Query OK, 0 rows affected (0.09 sec) mysql> CREATE TABLE t2 ( -> c1 INT, -> c2 VARCHAR(20) -> ) -> PARTITION BY RANGE(c1) ( -> PARTITION p0 VALUES LESS THAN (-5), -> PARTITION p1 VALUES LESS THAN (0), -> PARTITION p2 VALUES LESS THAN (10), -> PARTITION p3 VALUES LESS THAN MAXVALUE -> ); Query OK, 0 rows affected (0.09 sec) You can see the partitions created by these two *Note `CREATE TABLE': create-table. statements using the following query against the *Note `PARTITIONS': partitions-table. table in the `INFORMATION_SCHEMA' database: mysql> SELECT TABLE_NAME, PARTITION_NAME, TABLE_ROWS, AVG_ROW_LENGTH, DATA_LENGTH > FROM INFORMATION_SCHEMA.PARTITIONS > WHERE TABLE_SCHEMA = 'p' AND TABLE_NAME LIKE 't_'; +------------+----------------+------------+----------------+-------------+ | TABLE_NAME | PARTITION_NAME | TABLE_ROWS | AVG_ROW_LENGTH | DATA_LENGTH | +------------+----------------+------------+----------------+-------------+ | t1 | p0 | 0 | 0 | 0 | | t1 | p1 | 0 | 0 | 0 | | t1 | p2 | 0 | 0 | 0 | | t2 | p0 | 0 | 0 | 0 | | t2 | p1 | 0 | 0 | 0 | | t2 | p2 | 0 | 0 | 0 | | t2 | p3 | 0 | 0 | 0 | +------------+----------------+------------+----------------+-------------+ 7 rows in set (0.00 sec) (For more information about this table, see *Note partitions-table::.) Now let us populate each of these tables with a single row containing a `NULL' in the column used as the partitioning key, and verify that the rows were inserted using a pair of *Note `SELECT': select. statements: mysql> INSERT INTO t1 VALUES (NULL, 'mothra'); Query OK, 1 row affected (0.00 sec) mysql> INSERT INTO t2 VALUES (NULL, 'mothra'); Query OK, 1 row affected (0.00 sec) mysql> SELECT * FROM t1; +------+--------+ | id | name | +------+--------+ | NULL | mothra | +------+--------+ 1 row in set (0.00 sec) mysql> SELECT * FROM t2; +------+--------+ | id | name | +------+--------+ | NULL | mothra | +------+--------+ 1 row in set (0.00 sec) You can see which partitions are used to store the inserted rows by rerunning the previous query against *Note `INFORMATION_SCHEMA.PARTITIONS': partitions-table. and inspecting the output: mysql> SELECT TABLE_NAME, PARTITION_NAME, TABLE_ROWS, AVG_ROW_LENGTH, DATA_LENGTH > FROM INFORMATION_SCHEMA.PARTITIONS > WHERE TABLE_SCHEMA = 'p' AND TABLE_NAME LIKE 't_'; +------------+----------------+------------+----------------+-------------+ | TABLE_NAME | PARTITION_NAME | TABLE_ROWS | AVG_ROW_LENGTH | DATA_LENGTH | +------------+----------------+------------+----------------+-------------+ _| t1 | p0 | 1 | 20 | 20 |_ | t1 | p1 | 0 | 0 | 0 | | t1 | p2 | 0 | 0 | 0 | _| t2 | p0 | 1 | 20 | 20 |_ | t2 | p1 | 0 | 0 | 0 | | t2 | p2 | 0 | 0 | 0 | | t2 | p3 | 0 | 0 | 0 | +------------+----------------+------------+----------------+-------------+ 7 rows in set (0.01 sec) You can also demonstrate that these rows were stored in the lowest partition of each table by dropping these partitions, and then re-running the *Note `SELECT': select. statements: mysql> ALTER TABLE t1 DROP PARTITION p0; Query OK, 0 rows affected (0.16 sec) mysql> ALTER TABLE t2 DROP PARTITION p0; Query OK, 0 rows affected (0.16 sec) mysql> SELECT * FROM t1; Empty set (0.00 sec) mysql> SELECT * FROM t2; Empty set (0.00 sec) *Important*: Prior to MySQL 5.1.8, `RANGE' partitioning treated a partitioning expression value of `NULL' as 0 with respect to determining placement. (The only way to circumvent this behavior was to design tables so as not to permit nulls, usually by declaring columns `NOT NULL'.) If you have a `RANGE' partitioning scheme that depends on this earlier behavior, you must re-implement it when upgrading to MySQL 5.1.8 or later. (Bug#15447) `NULL' is also treated in this way for partitioning expressions that use SQL functions. Suppose that we define a table using a *Note `CREATE TABLE': create-table. statement such as this one: CREATE TABLE tndate ( id INT, dt DATE ) PARTITION BY RANGE( YEAR(dt) ) ( PARTITION p0 VALUES LESS THAN (1990), PARTITION p1 VALUES LESS THAN (2000), PARTITION p2 VALUES LESS THAN MAXVALUE ); As with other MySQL functions, `YEAR(NULL)' returns `NULL'. A row with a `dt' column value of `NULL' is treated as though the partitioning expression evaluated to a value less than any other value, and so is inserted into partition `p0'. Handling of `NULL' with `LIST' partitioning A table that is partitioned by `LIST' admits `NULL' values if and only if one of its partitions is defined using that value-list that contains `NULL'. The converse of this is that a table partitioned by `LIST' which does not explicitly use `NULL' in a value list rejects rows resulting in a `NULL' value for the partitioning expression, as shown in this example: mysql> CREATE TABLE ts1 ( -> c1 INT, -> c2 VARCHAR(20) -> ) -> PARTITION BY LIST(c1) ( -> PARTITION p0 VALUES IN (0, 3, 6), -> PARTITION p1 VALUES IN (1, 4, 7), -> PARTITION p2 VALUES IN (2, 5, 8) -> ); Query OK, 0 rows affected (0.01 sec) mysql> INSERT INTO ts1 VALUES (9, 'mothra'); `ERROR 1504 (HY000): Table has no partition for value 9' mysql> INSERT INTO ts1 VALUES (NULL, 'mothra'); `ERROR 1504 (HY000): Table has no partition for value NULL' Only rows having a `c1' value between `0' and `8' inclusive can be inserted into `ts1'. `NULL' falls outside this range, just like the number `9'. We can create tables `ts2' and `ts3' having value lists containing `NULL', as shown here: mysql> CREATE TABLE ts2 ( -> c1 INT, -> c2 VARCHAR(20) -> ) -> PARTITION BY LIST(c1) ( -> PARTITION p0 VALUES IN (0, 3, 6), -> PARTITION p1 VALUES IN (1, 4, 7), -> PARTITION p2 VALUES IN (2, 5, 8), -> PARTITION p3 VALUES IN (NULL) -> ); Query OK, 0 rows affected (0.01 sec) mysql> CREATE TABLE ts3 ( -> c1 INT, -> c2 VARCHAR(20) -> ) -> PARTITION BY LIST(c1) ( -> PARTITION p0 VALUES IN (0, 3, 6), -> PARTITION p1 VALUES IN (1, 4, 7, NULL), -> PARTITION p2 VALUES IN (2, 5, 8) -> ); Query OK, 0 rows affected (0.01 sec) When defining value lists for partitioning, you can (and should) treat `NULL' just as you would any other value. For example, both `VALUES IN (NULL)' and `VALUES IN (1, 4, 7, NULL)' are valid, as are `VALUES IN (1, NULL, 4, 7)', `VALUES IN (NULL, 1, 4, 7)', and so on. You can insert a row having `NULL' for column `c1' into each of the tables `ts2' and `ts3': mysql> INSERT INTO ts2 VALUES (NULL, 'mothra'); Query OK, 1 row affected (0.00 sec) mysql> INSERT INTO ts3 VALUES (NULL, 'mothra'); Query OK, 1 row affected (0.00 sec) By issuing the appropriate query against *Note `INFORMATION_SCHEMA.PARTITIONS': partitions-table, you can determine which partitions were used to store the rows just inserted (we assume, as in the previous examples, that the partitioned tables were created in the `p' database): mysql> SELECT TABLE_NAME, PARTITION_NAME, TABLE_ROWS, AVG_ROW_LENGTH, DATA_LENGTH > FROM INFORMATION_SCHEMA.PARTITIONS > WHERE TABLE_SCHEMA = 'p' AND TABLE_NAME LIKE 'ts_'; +------------+----------------+------------+----------------+-------------+ | TABLE_NAME | PARTITION_NAME | TABLE_ROWS | AVG_ROW_LENGTH | DATA_LENGTH | +------------+----------------+------------+----------------+-------------+ | ts2 | p0 | 0 | 0 | 0 | | ts2 | p1 | 0 | 0 | 0 | | ts2 | p2 | 0 | 0 | 0 | _| ts2 | p3 | 1 | 20 | 20 |_ | ts3 | p0 | 0 | 0 | 0 | _| ts3 | p1 | 1 | 20 | 20 |_ | ts3 | p2 | 0 | 0 | 0 | +------------+----------------+------------+----------------+-------------+ 7 rows in set (0.01 sec) As shown earlier in this section, you can also verify which partitions were used for storing the rows by deleting these partitions and then performing a *Note `SELECT': select. Handling of `NULL' with `HASH' and `KEY' partitioning `NULL' is handled somewhat differently for tables partitioned by `HASH' or `KEY'. In these cases, any partition expression that yields a `NULL' value is treated as though its return value were zero. We can verify this behavior by examining the effects on the file system of creating a table partitioned by `HASH' and populating it with a record containing appropriate values. Suppose that you have a table `th' (also in the `p' database) created using the following statement: mysql> CREATE TABLE th ( -> c1 INT, -> c2 VARCHAR(20) -> ) -> PARTITION BY HASH(c1) -> PARTITIONS 2; Query OK, 0 rows affected (0.00 sec) The partitions belonging to this table can be viewed using the query shown here: mysql> SELECT TABLE_NAME,PARTITION_NAME,TABLE_ROWS,AVG_ROW_LENGTH,DATA_LENGTH > FROM INFORMATION_SCHEMA.PARTITIONS > WHERE TABLE_SCHEMA = 'p' AND TABLE_NAME ='th'; +------------+----------------+------------+----------------+-------------+ | TABLE_NAME | PARTITION_NAME | TABLE_ROWS | AVG_ROW_LENGTH | DATA_LENGTH | +------------+----------------+------------+----------------+-------------+ | th | p0 | 0 | 0 | 0 | | th | p1 | 0 | 0 | 0 | +------------+----------------+------------+----------------+-------------+ 2 rows in set (0.00 sec) Note that `TABLE_ROWS' for each partition is 0. Now insert two rows into `th' whose `c1' column values are `NULL' and 0, and verify that these rows were inserted, as shown here: mysql> INSERT INTO th VALUES (NULL, 'mothra'), (0, 'gigan'); Query OK, 1 row affected (0.00 sec) mysql> SELECT * FROM th; +------+---------+ | c1 | c2 | +------+---------+ | NULL | mothra | +------+---------+ | 0 | gigan | +------+---------+ 2 rows in set (0.01 sec) Recall that for any integer N, the value of `NULL MOD N' is always `NULL'. For tables that are partitioned by `HASH' or `KEY', this result is treated for determining the correct partition as `0'. Checking the *Note `INFORMATION_SCHEMA.PARTITIONS': partitions-table. table once again, we can see that both rows were inserted into partition `p0': mysql> SELECT TABLE_NAME, PARTITION_NAME, TABLE_ROWS, AVG_ROW_LENGTH, DATA_LENGTH > FROM INFORMATION_SCHEMA.PARTITIONS > WHERE TABLE_SCHEMA = 'p' AND TABLE_NAME ='th'; +------------+----------------+------------+----------------+-------------+ | TABLE_NAME | PARTITION_NAME | TABLE_ROWS | AVG_ROW_LENGTH | DATA_LENGTH | +------------+----------------+------------+----------------+-------------+ _| th | p0 | 2 | 20 | 20 |_ | th | p1 | 0 | 0 | 0 | +------------+----------------+------------+----------------+-------------+ 2 rows in set (0.00 sec) If you repeat this example using `PARTITION BY KEY' in place of `PARTITION BY HASH' in the definition of the table, you can verify easily that `NULL' is also treated like 0 for this type of partitioning.  File: manual.info, Node: partitioning-management, Next: partitioning-pruning, Prev: partitioning-types, Up: partitioning 18.3 Partition Management ========================= * Menu: * partitioning-management-range-list:: Management of `RANGE' and `LIST' Partitions * partitioning-management-hash-key:: Management of `HASH' and `KEY' Partitions * partitioning-maintenance:: Maintenance of Partitions * partitioning-info:: Obtaining Information About Partitions MySQL 5.1 provides a number of ways to modify partitioned tables. It is possible to add, drop, redefine, merge, or split existing partitions. All of these actions can be carried out using the partitioning extensions to the *Note `ALTER TABLE': alter-table-partition-operations. statement *Note alter-table::. There are also ways to obtain information about partitioned tables and partitions. We discuss these topics in the sections that follow. * For information about partition management in tables partitioned by `RANGE' or `LIST', see *Note partitioning-management-range-list::. * For a discussion of managing `HASH' and `KEY' partitions, see *Note partitioning-management-hash-key::. * See *Note partitioning-info::, for a discussion of mechanisms provided in MySQL 5.1 for obtaining information about partitioned tables and partitions. * For a discussion of performing maintenance operations on partitions, see *Note partitioning-maintenance::. *Note*: In MySQL 5.1, all partitions of a partitioned table must have the same number of subpartitions, and it is not possible to change the subpartitioning once the table has been created. The statement *Note `ALTER TABLE ... PARTITION BY ...': alter-table-partition-operations. is available and is functional beginning with MySQL 5.1.6; previously in MySQL 5.1, this was accepted as valid syntax, but the statement did nothing. To change a table's partitioning scheme, it is necessary only to use the *Note `ALTER TABLE': alter-table-partition-operations. statement with a PARTITION_OPTIONS clause. This clause has the same syntax as that as used with *Note `CREATE TABLE': create-table. for creating a partitioned table, and always begins with the keywords `PARTITION BY'. Suppose that you have a table partitioned by range using the following *Note `CREATE TABLE': create-table. statement: CREATE TABLE trb3 (id INT, name VARCHAR(50), purchased DATE) PARTITION BY RANGE( YEAR(purchased) ) ( PARTITION p0 VALUES LESS THAN (1990), PARTITION p1 VALUES LESS THAN (1995), PARTITION p2 VALUES LESS THAN (2000), PARTITION p3 VALUES LESS THAN (2005) ); To repartition this table so that it is partitioned by key into two partitions using the `id' column value as the basis for the key, you can use this statement: ALTER TABLE trb3 PARTITION BY KEY(id) PARTITIONS 2; This has the same effect on the structure of the table as dropping the table and re-creating it using `CREATE TABLE trb3 PARTITION BY KEY(id) PARTITIONS 2;'. In MySQL 5.1.7 and earlier MySQL 5.1 releases, `ALTER TABLE ... ENGINE = ...' removed all partitioning from the affected table. Beginning with MySQL 5.1.8, this statement changes only the storage engine used by the table, and leaves the table's partitioning scheme intact. As of MySQL 5.1.8, use `ALTER TABLE ... REMOVE PARTITIONING' to remove a table's partitioning. See *Note alter-table::. *Important*: Only a single `PARTITION BY', `ADD PARTITION', `DROP PARTITION', `REORGANIZE PARTITION', or `COALESCE PARTITION' clause can be used in a given *Note `ALTER TABLE': alter-table-partition-operations. statement. If you (for example) wish to drop a partition and reorganize a table's remaining partitions, you must do so in two separate *Note `ALTER TABLE': alter-table-partition-operations. statements (one using `DROP PARTITION' and then a second one using `REORGANIZE PARTITIONS').  File: manual.info, Node: partitioning-management-range-list, Next: partitioning-management-hash-key, Prev: partitioning-management, Up: partitioning-management 18.3.1 Management of `RANGE' and `LIST' Partitions -------------------------------------------------- Range and list partitions are very similar with regard to how the adding and dropping of partitions are handled. For this reason we discuss the management of both sorts of partitioning in this section. For information about working with tables that are partitioned by hash or key, see *Note partitioning-management-hash-key::. Dropping a `RANGE' or `LIST' partition is more straightforward than adding one, so we discuss this first. Dropping a partition from a table that is partitioned by either `RANGE' or by `LIST' can be accomplished using the *Note `ALTER TABLE': alter-table-partition-operations. statement with a `DROP PARTITION' clause. Here is a very basic example, which supposes that you have already created a table which is partitioned by range and then populated with 10 records using the following *Note `CREATE TABLE': create-table. and *Note `INSERT': insert. statements: mysql> CREATE TABLE tr (id INT, name VARCHAR(50), purchased DATE) -> PARTITION BY RANGE( YEAR(purchased) ) ( -> PARTITION p0 VALUES LESS THAN (1990), -> PARTITION p1 VALUES LESS THAN (1995), -> PARTITION p2 VALUES LESS THAN (2000), -> PARTITION p3 VALUES LESS THAN (2005) -> ); Query OK, 0 rows affected (0.01 sec) mysql> INSERT INTO tr VALUES -> (1, 'desk organiser', '2003-10-15'), -> (2, 'CD player', '1993-11-05'), -> (3, 'TV set', '1996-03-10'), -> (4, 'bookcase', '1982-01-10'), -> (5, 'exercise bike', '2004-05-09'), -> (6, 'sofa', '1987-06-05'), -> (7, 'popcorn maker', '2001-11-22'), -> (8, 'aquarium', '1992-08-04'), -> (9, 'study desk', '1984-09-16'), -> (10, 'lava lamp', '1998-12-25'); Query OK, 10 rows affected (0.01 sec) You can see which items should have been inserted into partition `p2' as shown here: mysql> SELECT * FROM tr -> WHERE purchased BETWEEN '1995-01-01' AND '1999-12-31'; +------+-----------+------------+ | id | name | purchased | +------+-----------+------------+ | 3 | TV set | 1996-03-10 | | 10 | lava lamp | 1998-12-25 | +------+-----------+------------+ 2 rows in set (0.00 sec) To drop the partition named `p2', execute the following command: mysql> ALTER TABLE tr DROP PARTITION p2; Query OK, 0 rows affected (0.03 sec) *Note*: The *Note `NDBCLUSTER': mysql-cluster. storage engine does not support `ALTER TABLE ... DROP PARTITION'. It does, however, support the other partitioning-related extensions to *Note `ALTER TABLE': alter-table-partition-operations. that are described in this chapter. It is very important to remember that, _when you drop a partition, you also delete all the data that was stored in that partition_. You can see that this is the case by re-running the previous *Note `SELECT': select. query: mysql> SELECT * FROM tr WHERE purchased -> BETWEEN '1995-01-01' AND '1999-12-31'; Empty set (0.00 sec) Because of this, the requirement was added in MySQL 5.1.10 that you have the `DROP' privilege for a table before you can execute `ALTER TABLE ... DROP PARTITION' on that table. If you wish to drop all data from all partitions while preserving the table definition and its partitioning scheme, use the *Note `TRUNCATE TABLE': truncate-table. statement. (See *Note truncate-table::.) If you intend to change the partitioning of a table _without_ losing data, use `ALTER TABLE ... REORGANIZE PARTITION' instead. See below or in *Note alter-table::, for information about `REORGANIZE PARTITION'. If you now execute a *Note `SHOW CREATE TABLE': show-create-table. statement, you can see how the partitioning makeup of the table has been changed: mysql> SHOW CREATE TABLE tr\G *************************** 1. row *************************** Table: tr Create Table: CREATE TABLE `tr` ( `id` int(11) default NULL, `name` varchar(50) default NULL, `purchased` date default NULL ) ENGINE=MyISAM DEFAULT CHARSET=latin1 PARTITION BY RANGE ( YEAR(purchased) ) ( PARTITION p0 VALUES LESS THAN (1990) ENGINE = MyISAM, PARTITION p1 VALUES LESS THAN (1995) ENGINE = MyISAM, PARTITION p3 VALUES LESS THAN (2005) ENGINE = MyISAM ) 1 row in set (0.01 sec) When you insert new rows into the changed table with `purchased' column values between `'1995-01-01'' and `'2004-12-31'' inclusive, those rows will be stored in partition `p3'. You can verify this as follows: mysql> INSERT INTO tr VALUES (11, 'pencil holder', '1995-07-12'); Query OK, 1 row affected (0.00 sec) mysql> SELECT * FROM tr WHERE purchased -> BETWEEN '1995-01-01' AND '2004-12-31'; +------+----------------+------------+ | id | name | purchased | +------+----------------+------------+ | 11 | pencil holder | 1995-07-12 | | 1 | desk organiser | 2003-10-15 | | 5 | exercise bike | 2004-05-09 | | 7 | popcorn maker | 2001-11-22 | +------+----------------+------------+ 4 rows in set (0.00 sec) mysql> ALTER TABLE tr DROP PARTITION p3; Query OK, 0 rows affected (0.03 sec) mysql> SELECT * FROM tr WHERE purchased -> BETWEEN '1995-01-01' AND '2004-12-31'; Empty set (0.00 sec) Note that the number of rows dropped from the table as a result of `ALTER TABLE ... DROP PARTITION' is not reported by the server as it would be by the equivalent *Note `DELETE': delete. query. Dropping `LIST' partitions uses exactly the same `ALTER TABLE ... DROP PARTITION' syntax as used for dropping `RANGE' partitions. However, there is one important difference in the effect this has on your use of the table afterward: You can no longer insert into the table any rows having any of the values that were included in the value list defining the deleted partition. (See *Note partitioning-list::, for an example.) To add a new range or list partition to a previously partitioned table, use the `ALTER TABLE ... ADD PARTITION' statement. For tables which are partitioned by `RANGE', this can be used to add a new range to the end of the list of existing partitions. Suppose that you have a partitioned table containing membership data for your organization, which is defined as follows: CREATE TABLE members ( id INT, fname VARCHAR(25), lname VARCHAR(25), dob DATE ) PARTITION BY RANGE( YEAR(dob) ) ( PARTITION p0 VALUES LESS THAN (1970), PARTITION p1 VALUES LESS THAN (1980), PARTITION p2 VALUES LESS THAN (1990) ); Suppose further that the minimum age for members is 16. As the calendar approaches the end of 2005, you realize that you will soon be admitting members who were born in 1990 (and later in years to come). You can modify the `members' table to accommodate new members born in the years 1990 to 1999 as shown here: ALTER TABLE ADD PARTITION (PARTITION p3 VALUES LESS THAN (2000)); *Important*: With tables that are partitioned by range, you can use `ADD PARTITION' to add new partitions to the high end of the partitions list only. Trying to add a new partition in this manner between or before existing partitions will result in an error as shown here: mysql> ALTER TABLE members > ADD PARTITION ( > PARTITION p3 VALUES LESS THAN (1960)); ERROR 1463 (HY000): VALUES LESS THAN value must be strictly » increasing for each partition In a similar fashion, you can add new partitions to a table that is partitioned by `LIST'. Suppose a table `tt' is defined using the following *Note `CREATE TABLE': create-table. statement: CREATE TABLE tt ( id INT, data INT ) PARTITION BY LIST(data) ( PARTITION p0 VALUES IN (5, 10, 15), PARTITION p1 VALUES IN (6, 12, 18) ); You can add a new partition in which to store rows having the `data' column values `7', `14', and `21' as shown: ALTER TABLE tt ADD PARTITION (PARTITION p2 VALUES IN (7, 14, 21)); Note that you _cannot_ add a new `LIST' partition encompassing any values that are already included in the value list of an existing partition. If you attempt to do so, an error will result: mysql> ALTER TABLE tt ADD PARTITION > (PARTITION np VALUES IN (4, 8, 12)); ERROR 1465 (HY000): Multiple definition of same constant » in list partitioning Because any rows with the `data' column value `12' have already been assigned to partition `p1', you cannot create a new partition on table `tt' that includes `12' in its value list. To accomplish this, you could drop `p1', and add `np' and then a new `p1' with a modified definition. However, as discussed earlier, this would result in the loss of all data stored in `p1'--and it is often the case that this is not what you really want to do. Another solution might appear to be to make a copy of the table with the new partitioning and to copy the data into it using *Note `CREATE TABLE ... SELECT ...': create-table, then drop the old table and rename the new one, but this could be very time-consuming when dealing with a large amounts of data. This also might not be feasible in situations where high availability is a requirement. Beginning with MySQL 5.1.6, you can add multiple partitions in a single `ALTER TABLE ... ADD PARTITION' statement as shown here: CREATE TABLE employees ( id INT NOT NULL, fname VARCHAR(50) NOT NULL, lname VARCHAR(50) NOT NULL, hired DATE NOT NULL ) PARTITION BY RANGE( YEAR(hired) ) ( PARTITION p1 VALUES LESS THAN (1991), PARTITION p2 VALUES LESS THAN (1996), PARTITION p3 VALUES LESS THAN (2001), PARTITION p4 VALUES LESS THAN (2005) ); ALTER TABLE employees ADD PARTITION ( PARTITION p5 VALUES LESS THAN (2010), PARTITION p6 VALUES LESS THAN MAXVALUE ); Fortunately, MySQL's partitioning implementation provides ways to redefine partitions without losing data. Let us look first at a couple of simple examples involving `RANGE' partitioning. Recall the `members' table which is now defined as shown here: mysql> SHOW CREATE TABLE members\G *************************** 1. row *************************** Table: members Create Table: CREATE TABLE `members` ( `id` int(11) default NULL, `fname` varchar(25) default NULL, `lname` varchar(25) default NULL, `dob` date default NULL ) ENGINE=MyISAM DEFAULT CHARSET=latin1 PARTITION BY RANGE ( YEAR(dob) ) ( PARTITION p0 VALUES LESS THAN (1970) ENGINE = MyISAM, PARTITION p1 VALUES LESS THAN (1980) ENGINE = MyISAM, PARTITION p2 VALUES LESS THAN (1990) ENGINE = MyISAM. PARTITION p3 VALUES LESS THAN (2000) ENGINE = MyISAM ) Suppose that you would like to move all rows representing members born before 1960 into a separate partition. As we have already seen, this cannot be done using *Note `ALTER TABLE ... ADD PARTITION': alter-table-partition-operations. However, you can use another partition-related extension to *Note `ALTER TABLE': alter-table-partition-operations. to accomplish this: ALTER TABLE members REORGANIZE PARTITION p0 INTO ( PARTITION s0 VALUES LESS THAN (1960), PARTITION s1 VALUES LESS THAN (1970) ); In effect, this command splits partition `p0' into two new partitions `s0' and `s1'. It also moves the data that was stored in `p0' into the new partitions according to the rules embodied in the two `PARTITION ... VALUES ...' clauses, so that `s0' contains only those records for which `YEAR(dob)' is less than 1960 and `s1' contains those rows in which `YEAR(dob)' is greater than or equal to 1960 but less than 1970. A `REORGANIZE PARTITION' clause may also be used for merging adjacent partitions. You can return the `members' table to its previous partitioning as shown here: ALTER TABLE members REORGANIZE PARTITION s0,s1 INTO ( PARTITION p0 VALUES LESS THAN (1970) ); No data is lost in splitting or merging partitions using `REORGANIZE PARTITION'. In executing the above statement, MySQL moves all of the records that were stored in partitions `s0' and `s1' into partition `p0'. The general syntax for `REORGANIZE PARTITION' is shown here: ALTER TABLE TBL_NAME REORGANIZE PARTITION PARTITION_LIST INTO (PARTITION_DEFINITIONS); Here, TBL_NAME is the name of the partitioned table, and PARTITION_LIST is a comma-separated list of names of one or more existing partitions to be changed. PARTITION_DEFINITIONS is a comma-separated list of new partition definitions, which follow the same rules as for the PARTITION_DEFINITIONS list used in *Note `CREATE TABLE': create-table. (see *Note create-table::). It should be noted that you are not limited to merging several partitions into one, or to splitting one partition into many, when using `REORGANIZE PARTITION'. For example, you can reorganize all four partitions of the `members' table into two, as follows: ALTER TABLE members REORGANIZE PARTITION p0,p1,p2,p3 INTO ( PARTITION m0 VALUES LESS THAN (1980), PARTITION m1 VALUES LESS THAN (2000) ); You can also use `REORGANIZE PARTITION' with tables that are partitioned by `LIST'. Let us return to the problem of adding a new partition to the list-partitioned `tt' table and failing because the new partition had a value that was already present in the value-list of one of the existing partitions. We can handle this by adding a partition that contains only nonconflicting values, and then reorganizing the new partition and the existing one so that the value which was stored in the existing one is now moved to the new one: ALTER TABLE tt ADD PARTITION (PARTITION np VALUES IN (4, 8)); ALTER TABLE tt REORGANIZE PARTITION p1,np INTO ( PARTITION p1 VALUES IN (6, 18), PARTITION np VALUES in (4, 8, 12) ); Here are some key points to keep in mind when using `ALTER TABLE ... REORGANIZE PARTITION' to repartition tables that are partitioned by `RANGE' or `LIST': * The `PARTITION' clauses used to determine the new partitioning scheme are subject to the same rules as those used with a *Note `CREATE TABLE': create-table. statement. Most importantly, you should remember that the new partitioning scheme cannot have any overlapping ranges (applies to tables partitioned by `RANGE') or sets of values (when reorganizing tables partitioned by `LIST'). *Note*: Prior to MySQL 5.1.4, you could not reuse the names of existing partitions in the `INTO' clause, even when those partitions were being dropped or redefined. See *Note news-5-1-4::, for more information. * The combination of partitions in the PARTITION_DEFINITIONS list should account for the same range or set of values overall as the combined partitions named in the PARTITION_LIST. For instance, in the `members' table used as an example in this section, partitions `p1' and `p2' together cover the years 1980 through 1999. Therefore, any reorganization of these two partitions should cover the same range of years overall. * For tables partitioned by `RANGE', you can reorganize only adjacent partitions; you cannot skip over range partitions. For instance, you could not reorganize the `members' table used as an example in this section using a statement beginning with `ALTER TABLE members REORGANIZE PARTITION p0,p2 INTO ...' because `p0' covers the years prior to 1970 and `p2' the years from 1990 through 1999 inclusive, and thus the two are not adjacent partitions. * You cannot use `REORGANIZE PARTITION' to change the table's partitioning type; that is, you cannot (for example) change `RANGE' partitions to `HASH' partitions or _vice versa_. You also cannot use this command to change the partitioning expression or column. To accomplish either of these tasks without dropping and re-creating the table, you can use *Note `ALTER TABLE ... PARTITION BY ...': alter-table-partition-operations. For example: ALTER TABLE members PARTITION BY HASH( YEAR(dob) ) PARTITIONS 8;  File: manual.info, Node: partitioning-management-hash-key, Next: partitioning-maintenance, Prev: partitioning-management-range-list, Up: partitioning-management 18.3.2 Management of `HASH' and `KEY' Partitions ------------------------------------------------ Tables which are partitioned by hash or by key are very similar to one another with regard to making changes in a partitioning setup, and both differ in a number of ways from tables which have been partitioned by range or list. For that reason, this section addresses the modification of tables partitioned by hash or by key only. For a discussion of adding and dropping of partitions of tables that are partitioned by range or list, see *Note partitioning-management-range-list::. You cannot drop partitions from tables that are partitioned by `HASH' or `KEY' in the same way that you can from tables that are partitioned by `RANGE' or `LIST'. However, you can merge `HASH' or `KEY' partitions using the `ALTER TABLE ... COALESCE PARTITION' statement. Suppose that you have a table containing data about clients, which is divided into twelve partitions. The `clients' table is defined as shown here: CREATE TABLE clients ( id INT, fname VARCHAR(30), lname VARCHAR(30), signed DATE ) PARTITION BY HASH( MONTH(signed) ) PARTITIONS 12; To reduce the number of partitions from twelve to eight, execute the following *Note `ALTER TABLE': alter-table-partition-operations. command: mysql> ALTER TABLE clients COALESCE PARTITION 4; Query OK, 0 rows affected (0.02 sec) `COALESCE' works equally well with tables that are partitioned by `HASH', `KEY', `LINEAR HASH', or `LINEAR KEY'. Here is an example similar to the previous one, differing only in that the table is partitioned by `LINEAR KEY': mysql> CREATE TABLE clients_lk ( -> id INT, -> fname VARCHAR(30), -> lname VARCHAR(30), -> signed DATE -> ) -> PARTITION BY LINEAR KEY(signed) -> PARTITIONS 12; Query OK, 0 rows affected (0.03 sec) mysql> ALTER TABLE clients_lk COALESCE PARTITION 4; Query OK, 0 rows affected (0.06 sec) Records: 0 Duplicates: 0 Warnings: 0 Note that the number following `COALESCE PARTITION' is the number of partitions to merge into the remainder--in other words, it is the number of partitions to remove from the table. If you attempt to remove more partitions than the table has, the result is an error like the one shown: mysql> ALTER TABLE clients COALESCE PARTITION 18; ERROR 1478 (HY000): Cannot remove all partitions, use DROP TABLE instead To increase the number of partitions for the `clients' table from 12 to 18. use `ALTER TABLE ... ADD PARTITION' as shown here: ALTER TABLE clients ADD PARTITION PARTITIONS 6;  File: manual.info, Node: partitioning-maintenance, Next: partitioning-info, Prev: partitioning-management-hash-key, Up: partitioning-management 18.3.3 Maintenance of Partitions -------------------------------- A number of table and partition maintenance tasks can be carried out using SQL statements intended for such purposes on partitioned tables in MySQL 5.1. Table maintenance of partitioned tables can be accomplished using the statements *Note `CHECK TABLE': check-table, *Note `OPTIMIZE TABLE': optimize-table, *Note `ANALYZE TABLE': analyze-table, and *Note `REPAIR TABLE': repair-table, which are supported for partitioned tables as of MySQL 5.1.27. Also beginning with MySQL 5.1.27, you can use a number of extensions to *Note `ALTER TABLE': alter-table-partition-operations. for performing operations of this type on one or more partitions directly, as described in the following list: * Rebuilding partitions Rebuilds the partition; this has the same effect as dropping all records stored in the partition, then reinserting them. This can be useful for purposes of defragmentation. Example: ALTER TABLE t1 REBUILD PARTITION p0, p1; * Optimizing partitions If you have deleted a large number of rows from a partition or if you have made many changes to a partitioned table with variable-length rows (that is, having `VARCHAR', `BLOB', or `TEXT' columns), you can use `ALTER TABLE ... OPTIMIZE PARTITION' to reclaim any unused space and to defragment the partition data file. Example: ALTER TABLE t1 OPTIMIZE PARTITION p0, p1; Using `OPTIMIZE PARTITION' on a given partition is equivalent to running `CHECK PARTITION', `ANALYZE PARTITION', and `REPAIR PARTITION' on that partition. * Analyzing partitions This reads and stores the key distributions for partitions. Example: ALTER TABLE t1 ANALYZE PARTITION p3; * Repairing partitions This repairs corrupted partitions. Example: ALTER TABLE t1 REPAIR PARTITION p0,p1; * Checking partitions You can check partitions for errors in much the same way that you can use `CHECK TABLE' with nonpartitioned tables. Example: ALTER TABLE trb3 CHECK PARTITION p1; This command will tell you if the data or indexes in partition `p1' of table `t1' are corrupted. If this is the case, use `ALTER TABLE ... REPAIR PARTITION' to repair the partition. Each of the statements in the list just shown also supports the keyword `ALL' in place of the list of partition names. Using `ALL' causes the statement to act on all partitions in the table. *Note*: The statements `ALTER TABLE ... ANALYZE PARTITION', `ALTER TABLE ... CHECK PARTITION', `ALTER TABLE ... OPTIMIZE PARTITION', and `ALTER TABLE ... REPAIR PARTITION' were originally introduced in MySQL 5.1.5, but did not work properly and were disabled in MySQL 5.1.24. They were re-introduced in MySQL 5.1.27. (Bug#20129) The use of these partitioning-specific `ALTER TABLE' statements with tables which are not partitioned is not supported; beginning with MySQL 5.1.31, it is expressly not permitted. (Bug#39434) `ALTER TABLE ... REBUILD PARTITION' was also introduced in MySQL 5.1.5. The use of *Note `mysqlcheck': mysqlcheck. and *Note `myisamchk': myisamchk. is not supported with partitioned tables.  File: manual.info, Node: partitioning-info, Prev: partitioning-maintenance, Up: partitioning-management 18.3.4 Obtaining Information About Partitions --------------------------------------------- This section discusses obtaining information about existing partitions, which can be done in a number of ways. Methods of obtaining such information include the following: * Using the *Note `SHOW CREATE TABLE': show-create-table. statement to view the partitioning clauses used in creating a partitioned table. * Using the *Note `SHOW TABLE STATUS': show-table-status. statement to determine whether a table is partitioned. * Querying the *Note `INFORMATION_SCHEMA.PARTITIONS': partitions-table. table. * Using the statement *Note `EXPLAIN PARTITIONS SELECT': explain. to see which partitions are used by a given *Note `SELECT': select. As discussed elsewhere in this chapter, *Note `SHOW CREATE TABLE': show-create-table. includes in its output the `PARTITION BY' clause used to create a partitioned table. For example: mysql> SHOW CREATE TABLE trb3\G *************************** 1. row *************************** Table: trb3 Create Table: CREATE TABLE `trb3` ( `id` int(11) default NULL, `name` varchar(50) default NULL, `purchased` date default NULL ) ENGINE=MyISAM DEFAULT CHARSET=latin1 PARTITION BY RANGE (YEAR(purchased)) ( PARTITION p0 VALUES LESS THAN (1990) ENGINE = MyISAM, PARTITION p1 VALUES LESS THAN (1995) ENGINE = MyISAM, PARTITION p2 VALUES LESS THAN (2000) ENGINE = MyISAM, PARTITION p3 VALUES LESS THAN (2005) ENGINE = MyISAM ) 1 row in set (0.00 sec) *Note*: In early MySQL 5.1 releases, the `PARTITIONS' clause was not shown for tables partitioned by `HASH' or `KEY'. This issue was fixed in MySQL 5.1.6. *Note `SHOW TABLE STATUS': show-table-status. works with partitioned tables. Beginning with MySQL 5.1.9, its output is the same as that for nonpartitioned tables, except that the `Create_options' column contains the string `partitioned'. In MySQL 5.1.8 and earlier, the `Engine' column always contained the value `PARTITION'; beginning with MySQL 5.1.9, this column contains the name of the storage engine used by all partitions of the table. (See *Note show-table-status::, for more information about this statement.) You can also obtain information about partitions from `INFORMATION_SCHEMA', which contains a *Note `PARTITIONS': partitions-table. table. See *Note partitions-table::. Beginning with MySQL 5.1.5, it is possible to determine which partitions of a partitioned table are involved in a given *Note `SELECT': select. query using *Note `EXPLAIN PARTITIONS': explain. The `PARTITIONS' keyword adds a `partitions' column to the output of *Note `EXPLAIN': explain. listing the partitions from which records would be matched by the query. Suppose that you have a table `trb1' created and populated as follows: CREATE TABLE trb1 (id INT, name VARCHAR(50), purchased DATE) PARTITION BY RANGE(id) ( PARTITION p0 VALUES LESS THAN (3), PARTITION p1 VALUES LESS THAN (7), PARTITION p2 VALUES LESS THAN (9), PARTITION p3 VALUES LESS THAN (11) ); INSERT INTO trb1 VALUES (1, 'desk organiser', '2003-10-15'), (2, 'CD player', '1993-11-05'), (3, 'TV set', '1996-03-10'), (4, 'bookcase', '1982-01-10'), (5, 'exercise bike', '2004-05-09'), (6, 'sofa', '1987-06-05'), (7, 'popcorn maker', '2001-11-22'), (8, 'aquarium', '1992-08-04'), (9, 'study desk', '1984-09-16'), (10, 'lava lamp', '1998-12-25'); You can see which partitions are used in a query such as `SELECT * FROM trb1;', as shown here: mysql> EXPLAIN PARTITIONS SELECT * FROM trb1\G *************************** 1. row *************************** id: 1 select_type: SIMPLE table: trb1 partitions: p0,p1,p2,p3 type: ALL possible_keys: NULL key: NULL key_len: NULL ref: NULL rows: 10 Extra: Using filesort In this case, all four partitions are searched. However, when a limiting condition making use of the partitioning key is added to the query, you can see that only those partitions containing matching values are scanned, as shown here: mysql> EXPLAIN PARTITIONS SELECT * FROM trb1 WHERE id < 5\G *************************** 1. row *************************** id: 1 select_type: SIMPLE table: trb1 partitions: p0,p1 type: ALL possible_keys: NULL key: NULL key_len: NULL ref: NULL rows: 10 Extra: Using where *Note `EXPLAIN PARTITIONS': explain. provides information about keys used and possible keys, just as with the standard *Note `EXPLAIN SELECT': explain. statement: mysql> ALTER TABLE trb1 ADD PRIMARY KEY (id); Query OK, 10 rows affected (0.03 sec) Records: 10 Duplicates: 0 Warnings: 0 mysql> EXPLAIN PARTITIONS SELECT * FROM trb1 WHERE id < 5\G *************************** 1. row *************************** id: 1 select_type: SIMPLE table: trb1 partitions: p0,p1 type: range possible_keys: PRIMARY key: PRIMARY key_len: 4 ref: NULL rows: 7 Extra: Using where You should take note of the following restrictions and limitations on *Note `EXPLAIN PARTITIONS': explain.: * You cannot use the `PARTITIONS' and `EXTENDED' keywords together in the same *Note `EXPLAIN ... SELECT': explain. statement. Attempting to do so produces a syntax error. * If *Note `EXPLAIN PARTITIONS': explain. is used to examine a query against a nonpartitioned table, no error is produced, but the value of the `partitions' column is always `NULL'. As of MySQL 5.1.28, the `rows' column of *Note `EXPLAIN PARTITIONS': explain. output always displays the total number of rows in the table. Previously, this was the number of matching rows (see Bug#35745). See also *Note explain::.  File: manual.info, Node: partitioning-pruning, Next: partitioning-limitations, Prev: partitioning-management, Up: partitioning 18.4 Partition Pruning ====================== This section discusses an optimization known as _partition pruning_, which was implemented for partitioned tables in MySQL 5.1.6. The core concept behind partition pruning is relatively simple, and can be described as `Do not scan partitions where there can be no matching values'. Suppose that you have a partitioned table `t1' defined by this statement: CREATE TABLE t1 ( fname VARCHAR(50) NOT NULL, lname VARCHAR(50) NOT NULL, region_code TINYINT UNSIGNED NOT NULL, dob DATE NOT NULL ) PARTITION BY RANGE( region_code ) ( PARTITION p0 VALUES LESS THAN (64), PARTITION p1 VALUES LESS THAN (128), PARTITION p2 VALUES LESS THAN (192), PARTITION p3 VALUES LESS THAN MAXVALUE ); Consider the case where you wish to obtain results from a query such as this one: SELECT fname, lname, region_code, dob FROM t1 WHERE region_code > 125 AND region_code < 130; It is easy to see that none of the rows which ought to be returned will be in either of the partitions `p0' or `p3'; that is, we need to search only in partitions `p1' and `p2' to find matching rows. By doing so, it is possible to expend much less time and effort in finding matching rows than would be required to scan all partitions in the table. This `cutting away' of unneeded partitions is known as _pruning_. When the optimizer can make use of partition pruning in performing a query, execution of the query can be an order of magnitude faster than the same query against a nonpartitioned table containing the same column definitions and data. The query optimizer can perform pruning whenever a `WHERE' condition can be reduced to either one of the following two cases: * `PARTITION_COLUMN = CONSTANT' * `PARTITION_COLUMN IN (CONSTANT1, CONSTANT2, ..., CONSTANTN)' In the first case, the optimizer simply evaluates the partitioning expression for the value given, determines which partition contains that value, and scans only this partition. In many cases, the equal sign can be replaced with another arithmetic comparison, including `<', `>', `<=', `>=', and `<>'. Some queries using `BETWEEN' in the `WHERE' clause can also take advantage of partition pruning. See the examples later in this section. In the second case, the optimizer evaluates the partitioning expression for each value in the list, creates a list of matching partitions, and then scans only the partitions in this partition list. Pruning can also be applied to short ranges, which the optimizer can convert into equivalent lists of values. For instance, in the previous example, the `WHERE' clause can be converted to `WHERE region_code IN (125, 126, 127, 128, 129, 130)'. Then the optimizer can determine that the first three values in the list are found in partition `p1', the remaining three values in partition `p2', and that the other partitions contain no relevant values and so do not need to be searched for matching rows. This type of optimization can be applied whenever the partitioning expression consists of an equality or a range which can be reduced to a set of equalities, or when the partitioning expression represents an increasing or decreasing relationship. Pruning can also be applied for tables partitioned on a *Note `DATE': datetime. or *Note `DATETIME': datetime. column when the partitioning expression uses the `YEAR()' or `TO_DAYS()' function. Suppose that table `t2', defined as shown here, is partitioned on a *Note `DATE': datetime. column: CREATE TABLE t2 ( fname VARCHAR(50) NOT NULL, lname VARCHAR(50) NOT NULL, region_code TINYINT UNSIGNED NOT NULL, dob DATE NOT NULL ) PARTITION BY RANGE( YEAR(dob) ) ( PARTITION d0 VALUES LESS THAN (1970), PARTITION d1 VALUES LESS THAN (1975), PARTITION d2 VALUES LESS THAN (1980), PARTITION d3 VALUES LESS THAN (1985), PARTITION d4 VALUES LESS THAN (1990), PARTITION d5 VALUES LESS THAN (2000), PARTITION d6 VALUES LESS THAN (2005), PARTITION d7 VALUES LESS THAN MAXVALUE ); The following queries on `t2' can make of use partition pruning: SELECT * FROM t2 WHERE dob = '1982-06-23'; SELECT * FROM t2 WHERE dob BETWEEN '1991-02-15' AND '1997-04-25'; SELECT * FROM t2 WHERE dob >= '1984-06-21' AND dob <= '1999-06-21' In the case of the last query, the optimizer can also act as follows: 1. _Find the partition containing the low end of the range_. `YEAR('1984-06-21')' yields the value `1984', which is found in partition `d3'. 2. _Find the partition containing the high end of the range_. `YEAR('1999-06-21')' evaluates to `1999', which is found in partition `d5'. 3. _Scan only these two partitions and any partitions that may lie between them_. In this case, this means that only partitions `d3', `d4', and `d5' are scanned. The remaining partitions may be safely ignored (and are ignored). *Important*: Invalid `DATE' and `DATETIME' values referenced in the `WHERE' clause of a query on a partitioned table are treated as `NULL'. This means that a query such as `SELECT * FROM PARTITIONED_TABLE WHERE DATE_COLUMN < '2008-12-00'' does not return any values (see Bug#40972). So far, we have looked only at examples using `RANGE' partitioning, but pruning can be applied with other partitioning types as well. Consider a table that is partitioned by `LIST', where the partitioning expression is increasing or decreasing, such as the table `t3' shown here. (In this example, we assume for the sake of brevity that the `region_code' column is limited to values between 1 and 10 inclusive.) CREATE TABLE t3 ( fname VARCHAR(50) NOT NULL, lname VARCHAR(50) NOT NULL, region_code TINYINT UNSIGNED NOT NULL, dob DATE NOT NULL ) PARTITION BY LIST(region_code) ( PARTITION r0 VALUES IN (1, 3), PARTITION r1 VALUES IN (2, 5, 8), PARTITION r2 VALUES IN (4, 9), PARTITION r3 VALUES IN (6, 7, 10) ); For a query such as `SELECT * FROM t3 WHERE region_code BETWEEN 1 AND 3', the optimizer determines in which partitions the values 1, 2, and 3 are found (`r0' and `r1') and skips the remaining ones (`r2' and `r3'). For tables that are partitioned by `HASH' or `KEY', partition pruning is also possible in cases in which the `WHERE' clause uses a simple `=' relation against a column used in the partitioning expression. Consider a table created like this: CREATE TABLE t4 ( fname VARCHAR(50) NOT NULL, lname VARCHAR(50) NOT NULL, region_code TINYINT UNSIGNED NOT NULL, dob DATE NOT NULL ) PARTITION BY KEY(region_code) PARTITIONS 8; Any query, such as this one, that compares a column value with a constant can be pruned: SELECT * FROM t4 WHERE region_code = 7; Pruning can also be employed for short ranges, because the optimizer can turn such conditions into `IN' relations. For example, using the same table `t4' as defined previously, queries such as these can be pruned: SELECT * FROM t4 WHERE region_code > 2 AND region_code < 6; SELECT * FROM t4 WHERE region_code BETWEEN 3 AND 5; In both these cases, the `WHERE' clause is transformed by the optimizer into `WHERE region_code IN (3, 4, 5)'. *Important*: This optimization is used only if the range size is smaller than the number of partitions. Consider this query: SELECT * FROM t4 WHERE region_code BETWEEN 4 AND 12; The range in the `WHERE' clause covers 9 values (4, 5, 6, 7, 8, 9, 10, 11, 12), but `t4' has only 8 partitions. This means that the previous query cannot be pruned. Pruning can be used only on integer columns of tables partitioned by `HASH' or `KEY'. For example, this query on table `t4' cannot use pruning because `dob' is a *Note `DATE': datetime. column: SELECT * FROM t4 WHERE dob >= '2001-04-14' AND dob <= '2005-10-15'; However, if the table stores year values in an *Note `INT': numeric-types. column, then a query having `WHERE year_col >= 2001 AND year_col <= 2005' can be pruned. For a table that is partitioned by `KEY', has a composite primary key, and uses a composite partitioning key, it is possible to perform pruning for queries meeting the following two criteria: * The query must have a `WHERE' clause of the form `pkcol1 = c1 AND pkcol2 = c2 AND ... pkcolN = cN', where `pkcol1' ... `pkcolN' are the partitioning key columns and `c1' ... `cN' are constant values. * All columns of the partitioning key must be referenced in the `WHERE' clause. For example, suppose a table named `cities' is created as shown here: CREATE TABLE cities ( id INT NOT NULL AUTO_INCREMENT, name CHAR(35) NOT NULL DEFAULT '', country_code CHAR(3) NOT NULL DEFAULT '', district CHAR(20) NOT NULL DEFAULT '', population INT NOT NULL DEFAULT 0, PRIMARY KEY (ID, Population) ) PARTITION BY KEY () PARTITIONS 8; (Note that `PARTITION BY KEY()' is equivalent in this case to `PARTITION BY KEY(id, population)'.) Only a query that references both the `id' and `population' columns of this table can be pruned, as shown here: mysql> SELECT * FROM cities WHERE id = 101; +-----+------------+--------------+----------+------------+ | id | name | country_code | district | population | +-----+------------+--------------+----------+------------+ | 101 | Godoy Cruz | ARG | Mendoza | 206998 | +-----+------------+--------------+----------+------------+ 1 row in set (0.00 sec) mysql> SELECT * FROM cities WHERE population = 206998; +-----+------------+--------------+----------+------------+ | id | name | country_code | district | population | +-----+------------+--------------+----------+------------+ | 101 | Godoy Cruz | ARG | Mendoza | 206998 | +-----+------------+--------------+----------+------------+ 1 row in set (0.00 sec) mysql> EXPLAIN PARTITIONS SELECT * FROM cities WHERE id = 101; +----+-------------+--------+-------------------------+------+---------------+---------+---------+-------+------+-------+ | id | select_type | table | partitions | type | possible_keys | key | key_len | ref | rows | Extra | +----+-------------+--------+-------------------------+------+---------------+---------+---------+-------+------+-------+ | 1 | SIMPLE | cities | p0,p1,p2,p3,p4,p5,p6,p7 | ref | PRIMARY | PRIMARY | 4 | const | 8 | | +----+-------------+--------+-------------------------+------+---------------+---------+---------+-------+------+-------+ 1 row in set (0.00 sec) mysql> EXPLAIN PARTITIONS SELECT * FROM cities WHERE population = 206998; +----+-------------+--------+-------------------------+------+---------------+------+---------+------+------+-------------+ | id | select_type | table | partitions | type | possible_keys | key | key_len | ref | rows | Extra | +----+-------------+--------+-------------------------+------+---------------+------+---------+------+------+-------------+ | 1 | SIMPLE | cities | p0,p1,p2,p3,p4,p5,p6,p7 | ALL | NULL | NULL | NULL | NULL | 4079 | Using where | +----+-------------+--------+-------------------------+------+---------------+------+---------+------+------+-------------+ 1 row in set (0.00 sec) mysql> EXPLAIN PARTITIONS SELECT * FROM cities WHERE id = 101 AND population = 206998; +----+-------------+--------+------------+-------+---------------+---------+---------+-------------+------+-------+ | id | select_type | table | partitions | type | possible_keys | key | key_len | ref | rows | Extra | +----+-------------+--------+------------+-------+---------------+---------+---------+-------------+------+-------+ | 1 | SIMPLE | cities | p2 | const | PRIMARY | PRIMARY | 8 | const,const | 1 | | +----+-------------+--------+------------+-------+---------------+---------+---------+-------------+------+-------+ 1 row in set (0.00 sec) This limitation on pruning with composite partitioning keys is removed in MySQL 5.5.  File: manual.info, Node: partitioning-limitations, Prev: partitioning-pruning, Up: partitioning 18.5 Restrictions and Limitations on Partitioning ================================================= * Menu: * partitioning-limitations-partitioning-keys-unique-keys:: Partitioning Keys, Primary Keys, and Unique Keys * partitioning-limitations-storage-engines:: Partitioning Limitations Relating to Storage Engines * partitioning-limitations-functions:: Partitioning Limitations Relating to Functions This section discusses current restrictions and limitations on MySQL partitioning support. Prohibited constructs Beginning with MySQL 5.1.12, the following constructs are not permitted in partitioning expressions: * Stored procedures, stored functions, UDFs, or plugins. * Declared variables or user variables. For a list of SQL functions which are permitted in partitioning expressions, see *Note partitioning-limitations-functions::. Arithmetic and logical operators Use of the arithmetic operators `+', `-', and `*' is permitted in partitioning expressions. However, the result must be an integer value or `NULL' (except in the case of `[LINEAR] KEY' partitioning, as discussed elsewhere in this chapter; see *Note partitioning-types::, for more information). Beginning with MySQL 5.1.23, the `DIV' operator is also supported, and the `/' operator is not permitted. (Bug#30188, Bug#33182) Beginning with MySQL 5.1.12, the bit operators `|', `&', `^', `<<', `>>', and `~' are not permitted in partitioning expressions. Server SQL mode Tables employing user-defined partitioning do not preserve the SQL mode in effect at the time that they were created. As discussed in *Note server-sql-mode::, the results of many MySQL functions and operators may change according to the server SQL mode. Therefore, a change in the SQL mode at any time after the creation of partitioned tables may lead to major changes in the behavior of such tables, and could easily lead to corruption or loss of data. For these reasons, _it is strongly recommended that you never change the server SQL mode after creating partitioned tables_. Examples The following examples illustrate some changes in behavior of partitioned tables due to a change in the server SQL mode: 1. Error handling Suppose that you create a partitioned table whose partitioning expression is one such as `COLUMN DIV 0' or `COLUMN MOD 0', as shown here: mysql> CREATE TABLE tn (c1 INT) -> PARTITION BY LIST(1 DIV c1) ( -> PARTITION p0 VALUES IN (NULL), -> PARTITION p1 VALUES IN (1) -> ); Query OK, 0 rows affected (0.05 sec) The default behavior for MySQL is to return `NULL' for the result of a division by zero, without producing any errors: mysql> SELECT @@sql_mode; +------------+ | @@sql_mode | +------------+ | | +------------+ 1 row in set (0.00 sec) mysql> INSERT INTO tn VALUES (NULL), (0), (1); Query OK, 3 rows affected (0.00 sec) Records: 3 Duplicates: 0 Warnings: 0 However, changing the server SQL mode to treat division by zero as an error and to enforce strict error handling causes the same *Note `INSERT': insert. statement to fail, as shown here: mysql> SET sql_mode='STRICT_ALL_TABLES,ERROR_FOR_DIVISION_BY_ZERO'; Query OK, 0 rows affected (0.00 sec) mysql> INSERT INTO tn VALUES (NULL), (0), (1); `ERROR 1365 (22012): Division by 0' 2. Table accessibility Sometimes a change in the server SQL mode can make partitioned tables unusable. The following *Note `CREATE TABLE': create-table. statement can be executed successfully only if the `NO_UNSIGNED_SUBTRACTION' mode is in effect: mysql> SELECT @@sql_mode; +------------+ | @@sql_mode | +------------+ | | +------------+ 1 row in set (0.00 sec) mysql> CREATE TABLE tu (c1 BIGINT UNSIGNED) -> PARTITION BY RANGE(c1 - 10) ( -> PARTITION p0 VALUES LESS THAN (-5), -> PARTITION p1 VALUES LESS THAN (0), -> PARTITION p2 VALUES LESS THAN (5), -> PARTITION p3 VALUES LESS THAN (10), -> PARTITION p4 VALUES LESS THAN (MAXVALUE) -> ); `ERROR 1563 (HY000): Partition constant is out of partition function domain' mysql> SET sql_mode='NO_UNSIGNED_SUBTRACTION'; Query OK, 0 rows affected (0.00 sec) mysql> SELECT @@sql_mode; +-------------------------+ | @@sql_mode | +-------------------------+ | NO_UNSIGNED_SUBTRACTION | +-------------------------+ 1 row in set (0.00 sec) mysql> CREATE TABLE tu (c1 BIGINT UNSIGNED) -> PARTITION BY RANGE(c1 - 10) ( -> PARTITION p0 VALUES LESS THAN (-5), -> PARTITION p1 VALUES LESS THAN (0), -> PARTITION p2 VALUES LESS THAN (5), -> PARTITION p3 VALUES LESS THAN (10), -> PARTITION p4 VALUES LESS THAN (MAXVALUE) -> ); Query OK, 0 rows affected (0.05 sec) If you remove the `NO_UNSIGNED_SUBTRACTION' server SQL mode after creating `tu', you may no longer be able to access this table: mysql> SET sql_mode=''; Query OK, 0 rows affected (0.00 sec) mysql> SELECT * FROM tu; `ERROR 1563 (HY000): Partition constant is out of partition function domain' mysql> INSERT INTO tu VALUES (20); `ERROR 1563 (HY000): Partition constant is out of partition function domain' Server SQL modes also impact replication of partitioned tables. Differing SQL modes on master and slave can lead to partitioning expressions being evaluated differently; this can cause the distribution of data among partitions to be different in the master's and slave's copies of a given table, and may even cause inserts into partitioned tables that succeed on the master to fail on the slave. For best results, you should always use the same server SQL mode on the master and on the slave. Performance considerations Some affects of partitioning operations on performance are given in the following list: * File system operations Partitioning and repartitioning operations (such as *Note `ALTER TABLE': alter-table-partition-operations. with `PARTITION BY ...', `REORGANIZE PARTITIONS', or `REMOVE PARTITIONING') depend on file system operations for their implementation. This means that the speed of these operations is affected by such factors as file system type and characteristics, disk speed, swap space, file handling efficiency of the operating system, and MySQL server options and variables that relate to file handling. In particular, you should make sure that `large_files_support' is enabled and that `open_files_limit' is set properly. For partitioned tables using the `MyISAM' storage engine, increasing `myisam_max_sort_file_size' may improve performance; partitioning and repartitioning operations involving `InnoDB' tables may be made more efficient by enabling `innodb_file_per_table'. See also *Note partitioning-limitations-max-partitions::. * Table locks The process executing a partitioning operation on a table takes a write lock on the table. Reads from such tables are relatively unaffected; pending *Note `INSERT': insert. and *Note `UPDATE': update. operations are performed as soon as the partitioning operation has completed. * Storage engine Partitioning operations, queries, and update operations generally tend to be faster with `MyISAM' tables than with `InnoDB' or *Note `NDB': mysql-cluster. tables. * Use of indexes and partition pruning As with nonpartitioned tables, proper use of indexes can speed up queries on partitioned tables significantly. In addition, designing partitioned tables and queries on these tables to take advantage of _partition pruning_ can improve performance dramatically. See *Note partitioning-pruning::, for more information. * Performance with `LOAD DATA' Prior to MySQL 5.1.23, *Note `LOAD DATA': load-data. performed very poorly when importing into partitioned tables. The statement now uses buffering to improve performance; however, the buffer uses 130 KB memory per partition to achieve this. (Bug#26527) Maximum number of partitions The maximum possible number of partitions for a given table (that does not use the *Note `NDB': mysql-cluster. storage engine) is 1024. This includes subpartitions. The maximum possible number of user-defined partitions for a table using the *Note `NDBCLUSTER': mysql-cluster. storage engine is determined according to the version of the MySQL Cluster software being used, the number of data nodes, and other factors. See *Note mysql-cluster-nodes-groups-user-partitioning::, for more information. If, when creating tables with a large number of partitions (but less than the maximum), you encounter an error message such as `Got error ... from storage engine: Out of resources when opening file', you may be able to address the issue by increasing the value of the `open_files_limit' system variable. However, this is dependent on the operating system, and may not be possible or advisable on all platforms; see *Note not-enough-file-handles::, for more information. In some cases, using large numbers (hundreds) of partitions may also not be advisable due to other concerns, so using more partitions does not automatically lead to better results. See also *Note partitioning-limitations-file-system-ops::. Foreign keys not supported Partitioned tables do not support foreign keys. More specifically, this means that the following two statements are true: 1. Definitions of tables employing user-defined partitioning may not contain foreign key references to other tables. 2. No table definition may contain a foreign key reference to a partitioned table. The scope of these restrictions includes tables that use the `InnoDB' storage engine. `ALTER TABLE ... ORDER BY' An `ALTER TABLE ... ORDER BY COLUMN' statement run against a partitioned table causes ordering of rows only within each partition. FULLTEXT indexes Partitioned tables do not support `FULLTEXT' indexes. This includes partitioned tables employing the `MyISAM' storage engine. Spatial columns Columns with spatial data types such as `POINT' or `GEOMETRY' cannot be used in partitioned tables. Temporary tables As of MySQL 5.1.8, temporary tables cannot be partitioned. (Bug#17497) Log tables Beginning with MySQL 5.1.20, it is no longer possible to partition the log tables; beginning with that version, an *Note `ALTER TABLE ... PARTITION BY ...': alter-table-partition-operations. statement on such a table fails with an error. (Bug#27816) Data type of partitioning key A partitioning key must be either an integer column or an expression that resolves to an integer. The column or expression value may also be `NULL'. (See *Note partitioning-handling-nulls::.) The lone exception to this restriction occurs when partitioning by [`LINEAR'] `KEY', where it is possible to use columns of other types as partitioning keys, because MySQL's internal key-hashing functions produce the correct data type from these types. For example, the following *Note `CREATE TABLE': create-table. statement is valid: CREATE TABLE tkc (c1 CHAR) PARTITION BY KEY(c1) PARTITIONS 4; This exception does _not_ apply to *Note `BLOB': blob. or *Note `TEXT': blob. column types. Subqueries A partitioning key may not be a subquery, even if that subquery resolves to an integer value or `NULL'. Issues with subpartitions Subpartitions must use `HASH' or `KEY' partitioning. Only `RANGE' and `LIST' partitions may be subpartitioned; `HASH' and `KEY' partitions cannot be subpartitioned. Currently, `SUBPARTITION BY KEY' requires that the subpartitioning column or columns be specified explicitly, unlike the case with `PARTITION BY KEY', where it can be omitted (in which case the table's primary key column is used by default). Consider the table created by this statement: CREATE TABLE ts ( id INT NOT NULL AUTO_INCREMENT PRIMARY KEY, name VARCHAR(30) ); You can create a table having the same columns, partitioned by `KEY', using a statement such as this one: CREATE TABLE ts ( id INT NOT NULL AUTO_INCREMENT PRIMARY KEY, name VARCHAR(30) ) PARTITION BY KEY() PARTITIONS 4; The previous statement is treated as though it had been written like this, with the table's primary key column used as the partitioning column: CREATE TABLE ts ( id INT NOT NULL AUTO_INCREMENT PRIMARY KEY, name VARCHAR(30) ) PARTITION BY KEY(id) PARTITIONS 4; However, the following statement that attempts to create a subpartitioned table using the default column as the subpartitioning column fails, and the column must be specified for the statement to succeed, as shown here: mysql> CREATE TABLE ts ( -> id INT NOT NULL AUTO_INCREMENT PRIMARY KEY, -> name VARCHAR(30) -> ) -> PARTITION BY RANGE(id) -> SUBPARTITION BY KEY() -> SUBPARTITIONS 4 -> ( -> PARTITION p0 VALUES LESS THAN (100), -> PARTITION p1 VALUES LESS THAN (MAXVALUE) -> ); `ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ')' mysql> CREATE TABLE ts ( -> id INT NOT NULL AUTO_INCREMENT PRIMARY KEY, -> name VARCHAR(30) -> ) -> PARTITION BY RANGE(id) -> SUBPARTITION BY KEY(id) -> SUBPARTITIONS 4 -> ( -> PARTITION p0 VALUES LESS THAN (100), -> PARTITION p1 VALUES LESS THAN (MAXVALUE) -> ); Query OK, 0 rows affected (0.07 sec) This is a known issue (see Bug#51470). Key caches not supported Key caches are not supported for partitioned tables. The *Note `CACHE INDEX': cache-index. and *Note `LOAD INDEX INTO CACHE': load-index. statements, when you attempt to use them on tables having user-defined partitioning, fail with the errors `The storage engine for the table doesn't support assign_to_keycache' and `The storage engine for the table doesn't support preload_keys', respectively. `DELAYED' option not supported Use of *Note `INSERT DELAYED': insert-delayed. to insert rows into a partitioned table is not supported. Beginning with MySQL 5.1.23, attempting to do so fails with an error (see Bug#31210). `DATA DIRECTORY' and `INDEX DIRECTORY' options `DATA DIRECTORY' and `INDEX DIRECTORY' are subject to the following restrictions when used with partitioned tables: * Beginning with MySQL 5.1.23, table-level `DATA DIRECTORY' and `INDEX DIRECTORY' options are ignored (see Bug#32091). * On Windows, the `DATA DIRECTORY' and `INDEX DIRECTORY' options are not supported for individual partitions or subpartitions (Bug#30459). Repairing and rebuilding partitioned tables The statements *Note `CHECK TABLE': check-table, *Note `OPTIMIZE TABLE': optimize-table, *Note `ANALYZE TABLE': analyze-table, and *Note `REPAIR TABLE': repair-table. are supported for partitioned tables beginning with MySQL 5.1.27. (See Bug#20129.) In addition, you can use `ALTER TABLE ... REBUILD PARTITION' to rebuild one or more partitions of a partitioned table; `ALTER TABLE ... REORGANIZE PARTITION' also causes partitions to be rebuilt. Both of these statements were added in MySQL 5.1.5. See *Note alter-table::, for more information about these two statements. *Note `mysqlcheck': mysqlcheck. and *Note `myisamchk': myisamchk. are not supported with partitioned tables.  File: manual.info, Node: partitioning-limitations-partitioning-keys-unique-keys, Next: partitioning-limitations-storage-engines, Prev: partitioning-limitations, Up: partitioning-limitations 18.5.1 Partitioning Keys, Primary Keys, and Unique Keys ------------------------------------------------------- This section discusses the relationship of partitioning keys with primary keys and unique keys. The rule governing this relationship can be expressed as follows: All columns used in the partitioning expression for a partitioned table must be part of every unique key that the table may have. In other words, _every unique key on the table must use every column in the table's partitioning expression_. (This also includes the table's primary key, since it is by definition a unique key. This particular case is discussed later in this section.) For example, each of the following table creation statements is invalid: CREATE TABLE t1 ( col1 INT NOT NULL, col2 DATE NOT NULL, col3 INT NOT NULL, col4 INT NOT NULL, UNIQUE KEY (col1, col2) ) PARTITION BY HASH(col3) PARTITIONS 4; CREATE TABLE t2 ( col1 INT NOT NULL, col2 DATE NOT NULL, col3 INT NOT NULL, col4 INT NOT NULL, UNIQUE KEY (col1), UNIQUE KEY (col3) ) PARTITION BY HASH(col1 + col3) PARTITIONS 4; In each case, the proposed table would have at least one unique key that does not include all columns used in the partitioning expression. Each of the following statements is valid, and represents one way in which the corresponding invalid table creation statement could be made to work: CREATE TABLE t1 ( col1 INT NOT NULL, col2 DATE NOT NULL, col3 INT NOT NULL, col4 INT NOT NULL, UNIQUE KEY (col1, col2, col3) ) PARTITION BY HASH(col3) PARTITIONS 4; CREATE TABLE t2 ( col1 INT NOT NULL, col2 DATE NOT NULL, col3 INT NOT NULL, col4 INT NOT NULL, UNIQUE KEY (col1, col3) ) PARTITION BY HASH(col1 + col3) PARTITIONS 4; This example shows the error produced in such cases: mysql> CREATE TABLE t3 ( -> col1 INT NOT NULL, -> col2 DATE NOT NULL, -> col3 INT NOT NULL, -> col4 INT NOT NULL, -> UNIQUE KEY (col1, col2), -> UNIQUE KEY (col3) -> ) -> PARTITION BY HASH(col1 + col3) -> PARTITIONS 4; `ERROR 1491 (HY000): A PRIMARY KEY must include all columns in the table's partitioning function' The *Note `CREATE TABLE': create-table. statement fails because both `col1' and `col3' are included in the proposed partitioning key, but neither of these columns is part of both of unique keys on the table. This shows one possible fix for the invalid table definition: mysql> CREATE TABLE t3 ( -> col1 INT NOT NULL, -> col2 DATE NOT NULL, -> col3 INT NOT NULL, -> col4 INT NOT NULL, -> UNIQUE KEY (col1, col2, col3), -> UNIQUE KEY (col3) -> ) -> PARTITION BY HASH(col3) -> PARTITIONS 4; Query OK, 0 rows affected (0.05 sec) In this case, the proposed partitioning key `col3' is part of both unique keys, and the table creation statement succeeds. The following table cannot be partitioned at all, because there is no way to include in a partitioning key any columns that belong to both unique keys: CREATE TABLE t4 ( col1 INT NOT NULL, col2 INT NOT NULL, col3 INT NOT NULL, col4 INT NOT NULL, UNIQUE KEY (col1, col3), UNIQUE KEY (col2, col4) ); Since every primary key is by definition a unique key, this restriction also includes the table's primary key, if it has one. For example, the next two statements are invalid: CREATE TABLE t5 ( col1 INT NOT NULL, col2 DATE NOT NULL, col3 INT NOT NULL, col4 INT NOT NULL, PRIMARY KEY(col1, col2) ) PARTITION BY HASH(col3) PARTITIONS 4; CREATE TABLE t6 ( col1 INT NOT NULL, col2 DATE NOT NULL, col3 INT NOT NULL, col4 INT NOT NULL, PRIMARY KEY(col1, col3), UNIQUE KEY(col2) ) PARTITION BY HASH( YEAR(col2) ) PARTITIONS 4; In both cases, the primary key does not include all columns referenced in the partitioning expression. However, both of the next two statements are valid: CREATE TABLE t7 ( col1 INT NOT NULL, col2 DATE NOT NULL, col3 INT NOT NULL, col4 INT NOT NULL, PRIMARY KEY(col1, col2) ) PARTITION BY HASH(col1 + YEAR(col2)) PARTITIONS 4; CREATE TABLE t8 ( col1 INT NOT NULL, col2 DATE NOT NULL, col3 INT NOT NULL, col4 INT NOT NULL, PRIMARY KEY(col1, col2, col4), UNIQUE KEY(col2, col1) ) PARTITION BY HASH(col1 + YEAR(col2)) PARTITIONS 4; If a table has no unique keys--this includes having no primary key--then this restriction does not apply, and you may use any column or columns in the partitioning expression as long as the column type is compatible with the partitioning type. For the same reason, you cannot later add a unique key to a partitioned table unless the key includes all columns used by the table's partitioning expression. Consider the partitioned table created as shown here: mysql> CREATE TABLE t_no_pk (c1 INT, c2 INT) -> PARTITION BY RANGE(c1) ( -> PARTITION p0 VALUES LESS THAN (10), -> PARTITION p1 VALUES LESS THAN (20), -> PARTITION p2 VALUES LESS THAN (30), -> PARTITION p3 VALUES LESS THAN (40) -> ); Query OK, 0 rows affected (0.12 sec) It is possible to add a primary key to `t_no_pk' using either of these *Note `ALTER TABLE': alter-table-partition-operations. statements: # possible PK mysql> ALTER TABLE t_no_pk ADD PRIMARY KEY(c1); Query OK, 0 rows affected (0.13 sec) Records: 0 Duplicates: 0 Warnings: 0 # drop this PK mysql> ALTER TABLE t_no_pk DROP PRIMARY KEY; Query OK, 0 rows affected (0.10 sec) Records: 0 Duplicates: 0 Warnings: 0 # use another possible PK mysql> ALTER TABLE t_no_pk ADD PRIMARY KEY(c1, c2); Query OK, 0 rows affected (0.12 sec) Records: 0 Duplicates: 0 Warnings: 0 # drop this PK mysql> ALTER TABLE t_no_pk DROP PRIMARY KEY; Query OK, 0 rows affected (0.09 sec) Records: 0 Duplicates: 0 Warnings: 0 However, the next statement fails, because `c1' is part of the partitioning key, but is not part of the proposed primary key: # fails with error 1503 mysql> ALTER TABLE t_no_pk ADD PRIMARY KEY(c2); `ERROR 1503 (HY000): A PRIMARY KEY must include all columns in the table's partitioning function' Since `t_no_pk' has only `c1' in its partitioning expression, attempting to adding a unique key on `c2' alone fails. However, you can add a unique key that uses both `c1' and `c2'. These rules also apply to existing nonpartitioned tables that you wish to partition using *Note `ALTER TABLE ... PARTITION BY': alter-table-partition-operations. Consider a table `np_pk' created as shown here: mysql> CREATE TABLE np_pk ( -> id INT NOT NULL AUTO_INCREMENT, -> name VARCHAR(50), -> added DATE, -> PRIMARY KEY (id) -> ); Query OK, 0 rows affected (0.08 sec) The following *Note `ALTER TABLE': alter-table-partition-operations. statement fails with an error, because the `added' column is not part of any unique key in the table: mysql> ALTER TABLE np_pk -> PARTITION BY HASH( TO_DAYS(added) ) -> PARTITIONS 4; `ERROR 1503 (HY000): A PRIMARY KEY must include all columns in the table's partitioning function' However, this statement using the `id' column for the partitioning column is valid, as shown here: mysql> ALTER TABLE np_pk -> PARTITION BY HASH(id) -> PARTITIONS 4; Query OK, 0 rows affected (0.11 sec) Records: 0 Duplicates: 0 Warnings: 0 In the case of `np_pk', the only column that may be used as part of a partitioning expression is `id'; if you wish to partition this table using any other column or columns in the partitioning expression, you must first modify the table, either by adding the desired column or columns to the primary key, or by dropping the primary key altogether.  File: manual.info, Node: partitioning-limitations-storage-engines, Next: partitioning-limitations-functions, Prev: partitioning-limitations-partitioning-keys-unique-keys, Up: partitioning-limitations 18.5.2 Partitioning Limitations Relating to Storage Engines ----------------------------------------------------------- The following limitations apply to the use of storage engines with user-defined partitioning of tables. `MERGE' storage engine User-defined partitioning and the `MERGE' storage engine are not compatible. Tables using the `MERGE' storage engine cannot be partitioned. Partitioned tables cannot be merged. `FEDERATED' storage engine Partitioning of `FEDERATED' tables is not supported. Beginning with MySQL 5.1.15, it is not possible to create partitioned `FEDERATED' tables at all. `CSV' storage engine Partitioned tables using the `CSV' storage engine are not supported. Starting with MySQL 5.1.12, it is not possible to create partitioned `CSV' tables at all. `BLACKHOLE' storage engine Prior to MySQL 5.1.6, tables using the `BLACKHOLE' storage engine also could not be partitioned. `NDBCLUSTER' storage engine (MySQL Cluster) Partitioning by `KEY' (including `LINEAR KEY') is the only type of partitioning supported for the *Note `NDBCLUSTER': mysql-cluster. storage engine. Beginning with MySQL 5.1.12, it is not possible to create a MySQL Cluster table using any partitioning type other than [`LINEAR'] `KEY', and attempting to do so fails with an error. In addition, the maximum number of partitions that can be defined for an *Note `NDBCLUSTER': mysql-cluster. table depends on the number of data nodes and node groups in the cluster, the version of the MySQL Cluster software in use, and other factors. See *Note mysql-cluster-nodes-groups-user-partitioning::, for more information. Beginning with MySQL Cluster NDB 6.2.18, MySQL Cluster NDB 6.3.25, and MySQL Cluster NDB 7.0.6, *Note `CREATE TABLE': create-table. and *Note `ALTER TABLE': alter-table-partition-operations. statements that would cause a user-partitioned *Note `NDBCLUSTER': mysql-cluster. table not to meet either or both of the following two requirements are not permitted, and fail with an error (Bug#40709): 1. The table must have an explicit primary key. 2. All columns listed in the table's partitioning expression must be part of the primary key. Exception If a user-partitioned *Note `NDBCLUSTER': mysql-cluster. table is created using an empty column-list (that is, using `PARTITION BY KEY()' or `PARTITION BY LINEAR KEY()'), then no explicit primary key is required. Upgrading partitioned tables When performing an upgrade, tables which are partitioned by `KEY' and which use any storage engine other than *Note `NDBCLUSTER': mysql-cluster. must be dumped and reloaded. Same storage engine for all partitions All partitions of a partitioned table must use the same storage engine and it must be the same storage engine used by the table as a whole. In addition, if one does not specify an engine on the table level, then one must do either of the following when creating or altering a partitioned table: * Do _not_ specify any engine for _any_ partition or subpartition * Specify the engine for _all_ partitions or subpartitions  File: manual.info, Node: partitioning-limitations-functions, Prev: partitioning-limitations-storage-engines, Up: partitioning-limitations 18.5.3 Partitioning Limitations Relating to Functions ----------------------------------------------------- This section discusses limitations in MySQL Partitioning relating specifically to functions used in partitioning expressions. Beginning with MySQL 5.1.12, only the MySQL functions shown in the following table are supported in partitioning expressions. `ABS()' `CEILING()' (see *Note `DAY()' partitioning-limitations-ceiling-floor::) `DAYOFMONTH()' `DAYOFWEEK()' `DAYOFYEAR()' `DATEDIFF()' `EXTRACT()' (see *Note `FLOOR()' (see *Note partitioning-limitations-extract::)partitioning-limitations-ceiling-floor::) `HOUR()' `MICROSECOND()' `MINUTE()' `MOD()' `MONTH()' `QUARTER()' `SECOND()' `TIME_TO_SEC()' `TO_DAYS()' `UNIX_TIMESTAMP()' `WEEKDAY()' `YEAR()' (permitted in MySQL 5.1.43 and later, with *Note `TIMESTAMP': datetime. columns) `YEARWEEK()' In MySQL 5.1, partition pruning is supported only for the `TO_DAYS()' and `YEAR()' functions. See *Note partitioning-pruning::, for more information. `CEILING()' and `FLOOR()' Each of these functions returns an integer only if it is passed an argument of an exact numeric type, such as one of the *Note `INT': numeric-types. types or *Note `DECIMAL': numeric-types. This means, for example, that the following *Note `CREATE TABLE': create-table. statement fails with an error, as shown here: mysql> CREATE TABLE t (c FLOAT) PARTITION BY LIST( FLOOR(c) )( -> PARTITION p0 VALUES IN (1,3,5), -> PARTITION p1 VALUES IN (2,4,6) -> ); `ERROR 1490 (HY000): The PARTITION function returns the wrong type' `EXTRACT()' function with `WEEK' specifier The value returned by the `EXTRACT()' function, when used as `EXTRACT(WEEK FROM COL)', depends on the value of the `default_week_format' system variable. For this reason, beginning with MySQL 5.1.55, `EXTRACT()' is longer permitted as a partitioning function when it specifies the unit as `WEEK'. (Bug#54483) See *Note mathematical-functions::, for more information about the return types of these functions, as well as *Note numeric-types::.  File: manual.info, Node: stored-programs-views, Next: information-schema, Prev: partitioning, Up: Top 19 Stored Programs and Views **************************** * Menu: * stored-programs-defining:: Defining Stored Programs * stored-routines:: Using Stored Routines (Procedures and Functions) * triggers:: Using Triggers * events:: Using the Event Scheduler * views:: Using Views * stored-programs-security:: Access Control for Stored Programs and Views * stored-programs-logging:: Binary Logging of Stored Programs This chapter discusses stored programs and views, which are database objects defined in terms of SQL code that is stored on the server for later execution. Stored programs include these objects: * Stored routines, that is, stored procedures and functions. A stored procedure is invoked using the *Note `CALL': call. statement. A procedure does not have a return value but can modify its parameters for later inspection by the caller. It can also generate result sets to be returned to the client program. A stored function is used much like a built-in function. you invoke it in an expression and it returns a value during expression evaluation. * Triggers. A trigger is a named database object that is associated with a table and that is activated when a particular event occurs for the table, such as an insert or update. * Events. An event is a task that the server runs according to schedule. Views are stored queries that when referenced produce a result set. A view acts as a virtual table. This chapter describes how to use stored programs and views. The following sections provide additional information about SQL syntax for statements related to these objects: * For each object type, there are `CREATE', `ALTER', and `DROP' statements that control which objects exist and how they are defined. See *Note sql-syntax-data-definition::. * The *Note `CALL': call. statement is used to invoke stored procedures. See *Note call::. * Stored program definitions include a body that may use compound statements, loops, conditionals, and declared variables. See *Note sql-syntax-compound-statements::.  File: manual.info, Node: stored-programs-defining, Next: stored-routines, Prev: stored-programs-views, Up: stored-programs-views 19.1 Defining Stored Programs ============================= Each stored program contains a body that consists of an SQL statement. This statement may be a compound statement made up of several statements separated by semicolon (`;') characters. For example, the following stored procedure has a body made up of a *Note `BEGIN ... END': begin-end. block that contains a *Note `SET': set-option. statement and a *Note `REPEAT': repeat-statement. loop that itself contains another *Note `SET': set-option. statement: CREATE PROCEDURE dorepeat(p1 INT) BEGIN SET @x = 0; REPEAT SET @x = @x + 1; UNTIL @x > p1 END REPEAT; END; If you use the *Note `mysql': mysql. client program to define a stored program that contains the semicolon characters within its definition, a problem arises. By default, *Note `mysql': mysql. itself recognizes semicolon as a statement delimiter, so you must redefine the delimiter temporarily to cause *Note `mysql': mysql. to pass the entire stored program definition to the server. To redefine the *Note `mysql': mysql. delimiter, use the `delimiter' command. The following example shows how to do this for the `dorepeat()' procedure just shown. The delimiter is changed to `//' to enable the entire definition to be passed to the server as a single statement, and then restored to `;' before invoking the procedure. This enables the `;' delimiter used in the procedure body to be passed through to the server rather than being interpreted by *Note `mysql': mysql. itself. mysql> delimiter // mysql> CREATE PROCEDURE dorepeat(p1 INT) -> BEGIN -> SET @x = 0; -> REPEAT SET @x = @x + 1; UNTIL @x > p1 END REPEAT; -> END -> // Query OK, 0 rows affected (0.00 sec) mysql> delimiter ; mysql> CALL dorepeat(1000); Query OK, 0 rows affected (0.00 sec) mysql> SELECT @x; +------+ | @x | +------+ | 1001 | +------+ 1 row in set (0.00 sec) You can redefine the delimiter to a string other than `//', and the delimiter can consist of a single character or multiple characters. You should avoid the use of the backslash (``\'') character because that is the escape character for MySQL. The following is an example of a function that takes a parameter, performs an operation using an SQL function, and returns the result. In this case, it is unnecessary to use `delimiter' because the function definition contains no internal `;' statement delimiters: mysql> CREATE FUNCTION hello (s CHAR(20)) mysql> RETURNS CHAR(50) DETERMINISTIC -> RETURN CONCAT('Hello, ',s,'!'); Query OK, 0 rows affected (0.00 sec) mysql> SELECT hello('world'); +----------------+ | hello('world') | +----------------+ | Hello, world! | +----------------+ 1 row in set (0.00 sec)  File: manual.info, Node: stored-routines, Next: triggers, Prev: stored-programs-defining, Up: stored-programs-views 19.2 Using Stored Routines (Procedures and Functions) ===================================================== * Menu: * stored-routines-syntax:: Stored Routine Syntax * stored-routines-privileges:: Stored Routines and MySQL Privileges * stored-routines-metadata:: Stored Routine Metadata * stored-routines-last-insert-id:: Stored Procedures, Functions, Triggers, and `LAST_INSERT_ID()' Stored routines (procedures and functions) are supported in MySQL 5.1. A stored routine is a set of SQL statements that can be stored in the server. Once this has been done, clients don't need to keep reissuing the individual statements but can refer to the stored routine instead. Stored routines require the `proc' table in the `mysql' database. This table is created during the MySQL 5.1 installation procedure. If you are upgrading to MySQL 5.1 from an earlier version, be sure to update your grant tables to make sure that the `proc' table exists. See *Note mysql-upgrade::. Stored routines can be particularly useful in certain situations: * When multiple client applications are written in different languages or work on different platforms, but need to perform the same database operations. * When security is paramount. Banks, for example, use stored procedures and functions for all common operations. This provides a consistent and secure environment, and routines can ensure that each operation is properly logged. In such a setup, applications and users would have no access to the database tables directly, but can only execute specific stored routines. Stored routines can provide improved performance because less information needs to be sent between the server and the client. The tradeoff is that this does increase the load on the database server because more of the work is done on the server side and less is done on the client (application) side. Consider this if many client machines (such as Web servers) are serviced by only one or a few database servers. Stored routines also enable you to have libraries of functions in the database server. This is a feature shared by modern application languages that enable such design internally (for example, by using classes). Using these client application language features is beneficial for the programmer even outside the scope of database use. MySQL follows the SQL:2003 syntax for stored routines, which is also used by IBM's DB2. The MySQL implementation of stored routines is still in progress. All syntax described here is supported and any limitations and extensions are documented where appropriate. * Additional Resources * * You may find the Stored Procedures User Forum (http://forums.mysql.com/list.php?98) of use when working with stored procedures and functions. * For answers to some commonly asked questions regarding stored routines in MySQL, see *Note faqs-stored-procs::. * There are some restrictions on the use of stored routines. See *Note stored-program-restrictions::. * Binary logging for stored routines takes place as described in *Note stored-programs-logging::.  File: manual.info, Node: stored-routines-syntax, Next: stored-routines-privileges, Prev: stored-routines, Up: stored-routines 19.2.1 Stored Routine Syntax ---------------------------- A stored routine is either a procedure or a function. Stored routines are created with the *Note `CREATE PROCEDURE': create-procedure. and *Note `CREATE FUNCTION': create-function. statements (see *Note create-procedure::). A procedure is invoked using a *Note `CALL': call. statement (see *Note call::), and can only pass back values using output variables. A function can be called from inside a statement just like any other function (that is, by invoking the function's name), and can return a scalar value. The body of a stored routine can use compound statements (see *Note sql-syntax-compound-statements::). Stored routines can be dropped with the *Note `DROP PROCEDURE': drop-procedure. and *Note `DROP FUNCTION': drop-function. statements (see *Note drop-procedure::), and altered with the *Note `ALTER PROCEDURE': alter-procedure. and *Note `ALTER FUNCTION': alter-function. statements (see *Note alter-procedure::). A stored procedure or function is associated with a particular database. This has several implications: * When the routine is invoked, an implicit `USE DB_NAME' is performed (and undone when the routine terminates). *Note `USE': use. statements within stored routines are not permitted. * You can qualify routine names with the database name. This can be used to refer to a routine that is not in the current database. For example, to invoke a stored procedure `p' or function `f' that is associated with the `test' database, you can say `CALL test.p()' or `test.f()'. * When a database is dropped, all stored routines associated with it are dropped as well. Stored functions cannot be recursive. Recursion in stored procedures is permitted but disabled by default. To enable recursion, set the `max_sp_recursion_depth' server system variable to a value greater than zero. Stored procedure recursion increases the demand on thread stack space. If you increase the value of `max_sp_recursion_depth', it may be necessary to increase thread stack size by increasing the value of `thread_stack' at server startup. See *Note server-system-variables::, for more information. MySQL supports a very useful extension that enables the use of regular *Note `SELECT': select. statements (that is, without using cursors or local variables) inside a stored procedure. The result set of such a query is simply sent directly to the client. Multiple *Note `SELECT': select. statements generate multiple result sets, so the client must use a MySQL client library that supports multiple result sets. This means the client must use a client library from a version of MySQL at least as recent as 4.1. The client should also specify the `CLIENT_MULTI_RESULTS' option when it connects. For C programs, this can be done with the *Note `mysql_real_connect()': mysql-real-connect. C API function. See *Note mysql-real-connect::, and *Note c-api-multiple-queries::.  File: manual.info, Node: stored-routines-privileges, Next: stored-routines-metadata, Prev: stored-routines-syntax, Up: stored-routines 19.2.2 Stored Routines and MySQL Privileges ------------------------------------------- The MySQL grant system takes stored routines into account as follows: * The `CREATE ROUTINE' privilege is needed to create stored routines. * The `ALTER ROUTINE' privilege is needed to alter or drop stored routines. This privilege is granted automatically to the creator of a routine if necessary, and dropped from the creator when the routine is dropped. * The `EXECUTE' privilege is required to execute stored routines. However, this privilege is granted automatically to the creator of a routine if necessary (and dropped from the creator when the routine is dropped). Also, the default `SQL SECURITY' characteristic for a routine is `DEFINER', which enables users who have access to the database with which the routine is associated to execute the routine. * If the `automatic_sp_privileges' system variable is 0, the `EXECUTE' and `ALTER ROUTINE' privileges are not automatically granted to and dropped from the routine creator. * The creator of a routine is the account used to execute the `CREATE' statement for it. This might not be the same as the account named as the `DEFINER' in the routine definition. The server manipulates the `mysql.proc' table in response to statements that create, alter, or drop stored routines. It is not supported that the server will notice manual manipulation of this table.  File: manual.info, Node: stored-routines-metadata, Next: stored-routines-last-insert-id, Prev: stored-routines-privileges, Up: stored-routines 19.2.3 Stored Routine Metadata ------------------------------ Metadata about stored routines can be obtained as follows: * Query the *Note `ROUTINES': routines-table. table of the `INFORMATION_SCHEMA' database. See *Note routines-table::. * Use the *Note `SHOW CREATE PROCEDURE': show-create-procedure. and *Note `SHOW CREATE FUNCTION': show-create-function. statements to see routine definitions. See *Note show-create-procedure::. * Use the *Note `SHOW PROCEDURE STATUS': show-procedure-status. and *Note `SHOW FUNCTION STATUS': show-function-status. statements to see routine characteristics. See *Note show-procedure-status::. * `INFORMATION_SCHEMA' does not have a `PARAMETERS' table until MySQL 5.5, so applications that need to acquire routine parameter information at runtime must use workarounds such as parsing the output of `SHOW CREATE' statements or the `param_list' column of the `mysql.proc' table. `param_list' contents can be processed from within a stored routine, unlike the output from *Note `SHOW': show.  File: manual.info, Node: stored-routines-last-insert-id, Prev: stored-routines-metadata, Up: stored-routines 19.2.4 Stored Procedures, Functions, Triggers, and `LAST_INSERT_ID()' --------------------------------------------------------------------- Within the body of a stored routine (procedure or function) or a trigger, the value of `LAST_INSERT_ID()' changes the same way as for statements executed outside the body of these kinds of objects (see *Note information-functions::). The effect of a stored routine or trigger upon the value of `LAST_INSERT_ID()' that is seen by following statements depends on the kind of routine: * If a stored procedure executes statements that change the value of `LAST_INSERT_ID()', the changed value is seen by statements that follow the procedure call. * For stored functions and triggers that change the value, the value is restored when the function or trigger ends, so following statements do not see a changed value.  File: manual.info, Node: triggers, Next: events, Prev: stored-routines, Up: stored-programs-views 19.3 Using Triggers =================== * Menu: * trigger-syntax:: Trigger Syntax * trigger-metadata:: Trigger Metadata A trigger is a named database object that is associated with a table, and that activates when a particular event occurs for the table. Some uses for triggers are to perform checks of values to be inserted into a table or to perform calculations on values involved in an update. A trigger is defined to activate when an *Note `INSERT': insert, *Note `DELETE': delete, or *Note `UPDATE': update. statement executes for the associated table. A trigger can be set to activate either before or after the triggering statement. For example, you can have a trigger activate before each row that is inserted into a table or after each row that is updated. *Important*: MySQL triggers are activated by SQL statements _only_. They are not activated by changes in views, nor by changes to tables made by APIs that do not transmit SQL statements to the MySQL Server. This means that: * Triggers are not activated by changes in `INFORMATION_SCHEMA' tables, because these tables are actually views. * Triggers are not activated by updates made using the *Note `NDB': mysql-cluster. API. To use triggers if you have upgraded to MySQL 5.1 from an older release that did not support triggers, you should upgrade your grant tables so that they contain the trigger-related privileges. See *Note mysql-upgrade::. The following discussion describes the syntax for creating and dropping triggers, and shows some examples of how to use them. * Additional Resources * * You may find the Triggers User Forum (http://forums.mysql.com/list.php?100) of use when working with views. * For answers to some commonly asked questions regarding triggers in MySQL, see *Note faqs-triggers::. * There are some restrictions on the use of triggers; see *Note stored-program-restrictions::. * Binary logging for triggers takes place as described in *Note stored-programs-logging::.  File: manual.info, Node: trigger-syntax, Next: trigger-metadata, Prev: triggers, Up: triggers 19.3.1 Trigger Syntax --------------------- To create a trigger or drop a trigger, use the *Note `CREATE TRIGGER': create-trigger. or *Note `DROP TRIGGER': drop-trigger. statement. The syntax for these statements is described in *Note create-trigger::, and *Note drop-trigger::. Here is a simple example that associates a trigger with a table for *Note `INSERT': insert. statements. The trigger acts as an accumulator, summing the values inserted into one of the columns of the table. mysql> CREATE TABLE account (acct_num INT, amount DECIMAL(10,2)); Query OK, 0 rows affected (0.03 sec) mysql> CREATE TRIGGER ins_sum BEFORE INSERT ON account -> FOR EACH ROW SET @sum = @sum + NEW.amount; Query OK, 0 rows affected (0.06 sec) The *Note `CREATE TRIGGER': create-trigger. statement creates a trigger named `ins_sum' that is associated with the `account' table. It also includes clauses that specify the trigger activation time, the triggering event, and what to do with the trigger activates: * The keyword `BEFORE' indicates the trigger action time. In this case, the trigger should activate before each row inserted into the table. The other permissible keyword here is `AFTER'. * The keyword *Note `INSERT': insert. indicates the event that activates the trigger. In the example, *Note `INSERT': insert. statements cause trigger activation. You can also create triggers for *Note `DELETE': delete. and *Note `UPDATE': update. statements. * The statement following `FOR EACH ROW' defines the statement to execute each time the trigger activates, which occurs once for each row affected by the triggering statement In the example, the triggered statement is a simple *Note `SET': set-option. that accumulates the values inserted into the `amount' column. The statement refers to the column as `NEW.amount' which means `the value of the `amount' column to be inserted into the new row.' To use the trigger, set the accumulator variable to zero, execute an *Note `INSERT': insert. statement, and then see what value the variable has afterward: mysql> SET @sum = 0; mysql> INSERT INTO account VALUES(137,14.98),(141,1937.50),(97,-100.00); mysql> SELECT @sum AS 'Total amount inserted'; +-----------------------+ | Total amount inserted | +-----------------------+ | 1852.48 | +-----------------------+ In this case, the value of `@sum' after the *Note `INSERT': insert. statement has executed is `14.98 + 1937.50 - 100', or `1852.48'. To destroy the trigger, use a *Note `DROP TRIGGER': drop-trigger. statement. You must specify the schema name if the trigger is not in the default schema: mysql> DROP TRIGGER test.ins_sum; Triggers for a table are also dropped if you drop the table. Trigger names exist in the schema namespace, meaning that all triggers must have unique names within a schema. Triggers in different schemas can have the same name. In addition to the requirement that trigger names be unique for a schema, there are other limitations on the types of triggers you can create. In particular, you cannot have two triggers for a table that have the same activation time and activation event. For example, you cannot define two `BEFORE INSERT' triggers or two `AFTER UPDATE' triggers for a table. This should rarely be a significant limitation, because it is possible to define a trigger that executes multiple statements by using the *Note `BEGIN ... END': begin-end. compound statement construct after `FOR EACH ROW'. (An example appears later in this section.) The `OLD' and `NEW' keywords enable you to access columns in the rows affected by a trigger. (`OLD' and `NEW' are not case sensitive.) In an *Note `INSERT': insert. trigger, only `NEW.COL_NAME' can be used; there is no old row. In a *Note `DELETE': delete. trigger, only `OLD.COL_NAME' can be used; there is no new row. In an *Note `UPDATE': update. trigger, you can use `OLD.COL_NAME' to refer to the columns of a row before it is updated and `NEW.COL_NAME' to refer to the columns of the row after it is updated. A column named with `OLD' is read only. You can refer to it (if you have the *Note `SELECT': select. privilege), but not modify it. A column named with `NEW' can be referred to if you have the `SELECT' privilege for it. In a `BEFORE' trigger, you can also change its value with `SET NEW.COL_NAME = VALUE' if you have the `UPDATE' privilege for it. This means you can use a trigger to modify the values to be inserted into a new row or that are used to update a row. In a `BEFORE' trigger, the `NEW' value for an `AUTO_INCREMENT' column is 0, not the automatically generated sequence number that will be generated when the new record actually is inserted. `OLD' and `NEW' are MySQL extensions to triggers. By using the *Note `BEGIN ... END': begin-end. construct, you can define a trigger that executes multiple statements. Within the `BEGIN' block, you also can use other syntax that is permitted within stored routines such as conditionals and loops. However, just as for stored routines, if you use the *Note `mysql': mysql. program to define a trigger that executes multiple statements, it is necessary to redefine the *Note `mysql': mysql. statement delimiter so that you can use the `;' statement delimiter within the trigger definition. The following example illustrates these points. It defines an *Note `UPDATE': update. trigger that checks the new value to be used for updating each row, and modifies the value to be within the range from 0 to 100. This must be a `BEFORE' trigger because the value needs to be checked before it is used to update the row: mysql> delimiter // mysql> CREATE TRIGGER upd_check BEFORE UPDATE ON account -> FOR EACH ROW -> BEGIN -> IF NEW.amount < 0 THEN -> SET NEW.amount = 0; -> ELSEIF NEW.amount > 100 THEN -> SET NEW.amount = 100; -> END IF; -> END;// mysql> delimiter ; It can be easier to define a stored procedure separately and then invoke it from the trigger using a simple *Note `CALL': call. statement. This is also advantageous if you want to invoke the same routine from within several triggers. There are some limitations on what can appear in statements that a trigger executes when activated: * The trigger cannot use the *Note `CALL': call. statement to invoke stored procedures that return data to the client or that use dynamic SQL. (Stored procedures are permitted to return data to the trigger through `OUT' or `INOUT' parameters.) * The trigger cannot use statements that explicitly or implicitly begin or end a transaction such as *Note `START TRANSACTION': commit, *Note `COMMIT': commit, or *Note `ROLLBACK': commit. MySQL handles errors during trigger execution as follows: * If a `BEFORE' trigger fails, the operation on the corresponding row is not performed. * A `BEFORE' trigger is activated by the _attempt_ to insert or modify the row, regardless of whether the attempt subsequently succeeds. * An `AFTER' trigger is executed only if the `BEFORE' trigger (if any) and the row operation both execute successfully. * An error during either a `BEFORE' or `AFTER' trigger results in failure of the entire statement that caused trigger invocation. * For transactional tables, failure of a statement should cause rollback of all changes performed by the statement. Failure of a trigger causes the statement to fail, so trigger failure also causes rollback. For nontransactional tables, such rollback cannot be done, so although the statement fails, any changes performed prior to the point of the error remain in effect.  File: manual.info, Node: trigger-metadata, Prev: trigger-syntax, Up: triggers 19.3.2 Trigger Metadata ----------------------- Metadata about triggers can be obtained as follows: * Query the *Note `TRIGGERS': triggers-table. table of the `INFORMATION_SCHEMA' database. See *Note triggers-table::. * Use the *Note `SHOW TRIGGERS': show-triggers. statement. See *Note show-triggers::.  File: manual.info, Node: events, Next: views, Prev: triggers, Up: stored-programs-views 19.4 Using the Event Scheduler ============================== * Menu: * events-overview:: Event Scheduler Overview * events-configuration:: Event Scheduler Configuration * events-syntax:: Event Syntax * events-metadata:: Event Metadata * events-status-info:: Event Scheduler Status * events-privileges:: The Event Scheduler and MySQL Privileges The _MySQL Event Scheduler_ manages the scheduling and execution of events: Tasks that run according to schedule. Event support was added in MySQL 5.1.6. The following discussion covers the Event Scheduler and is divided into the following sections: * *Note events-overview::, provides an introduction to and conceptual overview of MySQL Events. * *Note events-syntax::, discusses the SQL statements for creating, altering, and dropping MySQL Events. * *Note events-metadata::, shows how to obtain information about events and how this information is stored by the MySQL Server. * *Note events-privileges::, discusses the privileges required to work with events and the ramifications that events have with regard to privileges when executing. Stored routines require the `event' table in the `mysql' database. This table is created during the MySQL 5.1 installation procedure. If you are upgrading to MySQL 5.1 from an earlier version, be sure to update your grant tables to make sure that the `event' table exists. See *Note mysql-upgrade::. * Additional Resources * * You may find the MySQL Event Scheduler User Forum (http://forums.mysql.com/list.php?119) of use when working with scheduled events. * There are some restrictions on the use of events; see *Note stored-program-restrictions::. * Binary logging for events takes place as described in *Note stored-programs-logging::.  File: manual.info, Node: events-overview, Next: events-configuration, Prev: events, Up: events 19.4.1 Event Scheduler Overview ------------------------------- MySQL Events are tasks that run according to a schedule. Therefore, we sometimes refer to them as _scheduled_ events. When you create an event, you are creating a named database object containing one or more SQL statements to be executed at one or more regular intervals, beginning and ending at a specific date and time. Conceptually, this is similar to the idea of the Unix `crontab' (also known as a `cron job') or the Windows Task Scheduler. Scheduled tasks of this type are also sometimes known as `temporal triggers', implying that these are objects that are triggered by the passage of time. While this is essentially correct, we prefer to use the term _events_ to avoid confusion with triggers of the type discussed in *Note triggers::. Events should more specifically not be confused with `temporary triggers'. Whereas a trigger is a database object whose statements are executed in response to a specific type of event that occurs on a given table, a (scheduled) event is an object whose statements are executed in response to the passage of a specified time interval. While there is no provision in the SQL Standard for event scheduling, there are precedents in other database systems, and you may notice some similarities between these implementations and that found in the MySQL Server. MySQL Events have the following major features and properties: * In MySQL 5.1.12 and later, an event is uniquely identified by its name and the schema to which it is assigned. (Previously, an event was also unique to its definer.) * An event performs a specific action according to a schedule. This action consists of an SQL statement, which can be a compound statement in a *Note `BEGIN ... END': begin-end. block if desired (see *Note sql-syntax-compound-statements::). An event's timing can be either _one-time_ or _recurrent_. A one-time event executes one time only. A recurrent event repeats its action at a regular interval, and the schedule for a recurring event can be assigned a specific start day and time, end day and time, both, or neither. (By default, a recurring event's schedule begins as soon as it is created, and continues indefinitely, until it is disabled or dropped.) If a repeating event does not terminate within its scheduling interval, the result may be multiple instances of the event executing simultaneously. If this is undesirable, you should institute a mechanism to prevent simultaneous instances. For example, you could use the `GET_LOCK()' function, or row or table locking. * Users can create, modify, and drop scheduled events using SQL statements intended for these purposes. Syntactically invalid event creation and modification statements fail with an appropriate error message. _A user may include statements in an event's action which require privileges that the user does not actually have_. The event creation or modification statement succeeds but the event's action fails. See *Note events-privileges:: for details. * Many of the properties of an event can be set or modified using SQL statements. These properties include the event's name, timing, persistence (that is, whether it is preserved following the expiration of its schedule), status (enabled or disabled), action to be performed, and the schema to which it is assigned. See *Note alter-event::. The default definer of an event is the user who created the event, unless the event has been altered, in which case the definer is the user who issued the last *Note `ALTER EVENT': alter-event. statement affecting that event. An event can be modified by any user having the `EVENT' privilege on the database for which the event is defined. (Prior to MySQL 5.1.12, only an event's definer, or a user having privileges on the `mysql.event' table, could modify a given event.) See *Note events-privileges::. * An event's action statement may include most SQL statements permitted within stored routines. For restrictions, see *Note stored-program-restrictions::.  File: manual.info, Node: events-configuration, Next: events-syntax, Prev: events-overview, Up: events 19.4.2 Event Scheduler Configuration ------------------------------------ Events are executed by a special _event scheduler thread_; when we refer to the Event Scheduler, we actually refer to this thread. When running, the event scheduler thread and its current state can be seen by users having the `PROCESS' privilege in the output of *Note `SHOW PROCESSLIST': show-processlist, as shown in the discussion that follows. The global `event_scheduler' system variable determines whether the Event Scheduler is enabled and running on the server. Beginning with MySQL 5.1.12, it has one of these 3 values, which affect event scheduling as described here: * `OFF': The Event Scheduler is stopped. The event scheduler thread does not run, is not shown in the output of *Note `SHOW PROCESSLIST': show-processlist, and no scheduled events are executed. `OFF' is the default value for `event_scheduler'. When the Event Scheduler is stopped (`event_scheduler' is `OFF'), it can be started by setting the value of `event_scheduler' to `ON'. (See next item.) * `ON': The Event Scheduler is started; the event scheduler thread runs and executes all scheduled events. When the Event Scheduler is `ON', the event scheduler thread is listed in the output of *Note `SHOW PROCESSLIST': show-processlist. as a daemon process, and its state is represented as shown here: mysql> SHOW PROCESSLIST\G *************************** 1. row *************************** Id: 1 User: root Host: localhost db: NULL Command: Query Time: 0 State: NULL Info: show processlist *************************** 2. row *************************** Id: 2 User: event_scheduler Host: localhost db: NULL Command: Daemon Time: 3 State: Waiting for next activation Info: NULL 2 rows in set (0.00 sec) Event scheduling can be stopped by setting the value of `event_scheduler' to `OFF'. * `DISABLED': This value renders the Event Scheduler nonoperational. When the Event Scheduler is `DISABLED', the event scheduler thread does not run (and so does not appear in the output of *Note `SHOW PROCESSLIST': show-processlist.). In addition, the Event Scheduler state cannot be changed at runtime. If the Event Scheduler status has not been set to `DISABLED', `event_scheduler' can be toggled between `ON' and `OFF' (using *Note `SET': set-option.). It is also possible to use `0' for `OFF', and `1' for `ON' when setting this variable. Thus, any of the following 4 statements can be used in the *Note `mysql': mysql. client to turn on the Event Scheduler: SET GLOBAL event_scheduler = ON; SET @@global.event_scheduler = ON; SET GLOBAL event_scheduler = 1; SET @@global.event_scheduler = 1; Similarly, any of these 4 statements can be used to turn off the Event Scheduler: SET GLOBAL event_scheduler = OFF; SET @@global.event_scheduler = OFF; SET GLOBAL event_scheduler = 0; SET @@global.event_scheduler = 0; Although `ON' and `OFF' have numeric equivalents, the value displayed for `event_scheduler' by *Note `SELECT': select. or *Note `SHOW VARIABLES': show-variables. is always one of `OFF', `ON', or `DISABLED'. _`DISABLED' has no numeric equivalent_. For this reason, `ON' and `OFF' are usually preferred over `1' and `0' when setting this variable. Note that attempting to set `event_scheduler' without specifying it as a global variable causes an error: mysql< SET @@event_scheduler = OFF; `ERROR 1229 (HY000): Variable 'event_scheduler' is a GLOBAL variable and should be set with SET GLOBAL' *Important*: It is possible to set the Event Scheduler to `DISABLED' only at server startup. If `event_scheduler' is `ON' or `OFF', you cannot set it to `DISABLED' at runtime. Also, if the Event Scheduler is set to `DISABLED' at startup, you cannot change the value of `event_scheduler' at runtime. To disable the event scheduler, use one of the following two methods: * As a command-line option when starting the server: --event-scheduler=DISABLED * In the server configuration file (`my.cnf', or `my.ini' on Windows systems), include the line where it will be read by the server (for example, in a `[mysqld]' section): event_scheduler=DISABLED To enable the Event Scheduler, restart the server without the `--event-scheduler=DISABLED' command-line option, or after removing or commenting out the line containing `event-scheduler=DISABLED' in the server configuration file, as appropriate. Alternatively, you can use `ON' (or `1') or `OFF' (or `0') in place of the `DISABLED' value when starting the server. *Note*: You can issue event-manipulation statements when `event_scheduler' is set to `DISABLED'. No warnings or errors are generated in such cases (provided that the statements are themselves valid). However, scheduled events cannot execute until this variable is set to `ON' (or `1'). Once this has been done, the event scheduler thread executes all events whose scheduling conditions are satisfied. In MySQL 5.1.11, `event_scheduler' behaved as follows: this variable could take one of the values `0' (or `OFF'), `1' (or `ON'), or `2'. Setting it to `0' turned event scheduling off, so that the event scheduler thread did not run; the `event_scheduler' variable could not be set to this value while the server was running. Setting it to `1' so that the event scheduler thread ran and executed scheduled events. In this state, the event scheduler thread appeared to be sleeping when viewed with *Note `SHOW PROCESSLIST': show-processlist. When `event_scheduler' was set to `2' (which was the default value), the Event Scheduler was considered to be `suspended'; the event scheduler thread ran and could be seen in the output of *Note `SHOW PROCESSLIST': show-processlist. (where `Suspended' was displayed in the `State' column), but did not execute any scheduled events. The value of `event_scheduler' could be changed only between `1' (or `ON') and `2' while the server was running. Setting it to `0' (or `OFF') required a server restart, as did changing its value from `0' (or `OFF') to `1' (or `ON') or `2'. Prior to MySQL 5.1.11, `event_scheduler' could take one of only the 2 values `0'|`OFF' or `1'|`ON', and the default value was `0'|`OFF'. It was also possible to start and stop the event scheduler thread while the MySQL server was running. For more information concerning the reasons for these changes in behavior, see Bug#17619. Beginning with MySQL 5.1.17, starting the MySQL server with the `--skip-grant-tables' option causes `event_scheduler' to be set to `DISABLED', overriding any other value set either on the command line or in the `my.cnf' or `my.ini' file (Bug#26807). For SQL statements used to create, alter, and drop events, see *Note events-syntax::. MySQL 5.1.6 and later provides an *Note `EVENTS': events-table. table in the `INFORMATION_SCHEMA' database. This table can be queried to obtain information about scheduled events which have been defined on the server. See *Note events-metadata::, and *Note events-table::, for more information. For information regarding event scheduling and the MySQL privilege system, see *Note events-privileges::.  File: manual.info, Node: events-syntax, Next: events-metadata, Prev: events-configuration, Up: events 19.4.3 Event Syntax ------------------- MySQL 5.1.6 and later provides several SQL statements for working with scheduled events: * New events are defined using the *Note `CREATE EVENT': create-event. statement. See *Note create-event::. * The definition of an existing event can be changed by means of the *Note `ALTER EVENT': alter-event. statement. See *Note alter-event::. * When a scheduled event is no longer wanted or needed, it can be deleted from the server by its definer using the *Note `DROP EVENT': drop-event. statement. See *Note drop-event::. Whether an event persists past the end of its schedule also depends on its `ON COMPLETION' clause, if it has one. See *Note create-event::. An event can be dropped by any user having the `EVENT' privilege for the database on which the event is defined. Prior to MySQL 5.1.12, a user other than the definer required privileges on the `mysql.event' table. See *Note events-privileges::.  File: manual.info, Node: events-metadata, Next: events-status-info, Prev: events-syntax, Up: events 19.4.4 Event Metadata --------------------- Metadata about events can be obtained as follows: * Query the `event' table of the `mysql' database. * Query the *Note `EVENTS': events-table. table of the `INFORMATION_SCHEMA' database. See *Note events-table::. * Use the *Note `SHOW CREATE EVENT': show-create-event. statement. See *Note show-create-event::. * Use the *Note `SHOW EVENTS': show-events. statement. See *Note show-events::. *Event Scheduler Time Representation* Each session in MySQL has a session time zone (STZ). This is the session `time_zone' value that is initialized from the server's global `time_zone' value when the session begins but may be changed during the session. The session time zone that is current when a *Note `CREATE EVENT': create-event. or *Note `ALTER EVENT': alter-event. statement executes is used to interpret times specified in the event definition. This becomes the event time zone (ETZ); that is, the time zone that is used for event scheduling and is in effect within the event as it executes. For representation of event information in the `mysql.event' table, the `execute_at', `starts', and `ends' times are converted to UTC and stored along with the event time zone. This enables event execution to proceed as defined regardless of any subsequent changes to the server time zone or daylight saving time effects. The `last_executed' time is also stored in UTC. If you select information from `mysql.event', the times just mentioned are retrieved as UTC values. These times can also be obtained by selecting from the *Note `INFORMATION_SCHEMA.EVENTS': events-table. table or from *Note `SHOW EVENTS': show-events, but they are reported as ETZ values. Other times available from these sources indicate when an event was created or last altered; these are displayed as STZ values. The following table summarizes representation of event times. Value `mysql.event' *Note *Note `SHOW `INFORMATION_SCHEMA.EVENTS':EVENTS': events-table. show-events. Execute at UTC ETZ ETZ Starts UTC ETZ ETZ Ends UTC ETZ ETZ Last executed UTC ETZ n/a Created STZ STZ n/a Last altered STZ STZ n/a The preceding table applies for MySQL 5.1.17 and up. Prior to MySQL 5.1.17, the event time zone is not stored in the `mysql.event' table or available from *Note `INFORMATION_SCHEMA.EVENTS': events-table. or *Note `SHOW EVENTS': show-events. Times that are displayed using ETZ from 5.1.17 and up are displayed in UTC before 5.1.17, as shown in the following table. Value `mysql.event' *Note *Note `SHOW `INFORMATION_SCHEMA.EVENTS':EVENTS': events-table. show-events. Execute at UTC UTC UTC Starts UTC UTC UTC Ends UTC UTC UTC Last executed UTC UTC n/a Created STZ STZ n/a Last altered STZ STZ n/a  File: manual.info, Node: events-status-info, Next: events-privileges, Prev: events-metadata, Up: events 19.4.5 Event Scheduler Status ----------------------------- The Event Scheduler writes information about event execution that terminates with an error or warning to the MySQL Server's error log. See *Note events-privileges:: for an example. (Before MySQL 5.1.31, the Event Scheduler also logged messages when events started execution and terminated successfully.) Information about the state of the Event Scheduler for debugging and troubleshooting purposes can be obtained as follows: * In debugging builds of MySQL 5.1.11, you can use the `SHOW SCHEDULER STATUS' statement; see *Note show-scheduler-status::. This statement was removed in MySQL 5.1.12. We intend to implement an SQL statement providing similar functionality in a future MySQL release. * Beginning with MySQL 5.1.12, event scheduler status information can be obtained by running *Note `mysqladmin debug': mysqladmin. (see *Note mysqladmin::); after running this command, the server's error log contains output relating to the Event Scheduler, similar to what is shown here: Events status: LLA = Last Locked At LUA = Last Unlocked At WOC = Waiting On Condition DL = Data Locked Event scheduler status: State : INITIALIZED Thread id : 0 LLA : init_scheduler:313 LUA : init_scheduler:318 WOC : NO Workers : 0 Executed : 0 Data locked: NO Event queue status: Element count : 1 Data locked : NO Attempting lock : NO LLA : init_queue:148 LUA : init_queue:168 WOC : NO Next activation : 0000-00-00 00:00:00 In statements that occur as part of events executed by the Event Scheduler, diagnostics messages (not only errors, but also warnings) are written to the error log, and, on Windows, to the application event log. For frequently executed events, it is possible for this to result in many logged messages. For example, for `SELECT ... INTO VAR_LIST' statements, if the query returns no rows, a warning with error code 1329 occurs (`No data'), and the variable values remain unchanged. If the query returns multiple rows, error 1172 occurs (`Result consisted of more than one row'). For either condition, you can avoid having the warnings be logged by declaring a condition handler; see *Note declare-handler::. For statements that may retrieve multiple rows, another strategy is to use `LIMIT 1' to limit the result set to a single row.  File: manual.info, Node: events-privileges, Prev: events-status-info, Up: events 19.4.6 The Event Scheduler and MySQL Privileges ----------------------------------------------- To enable or disable the execution of scheduled events, it is necessary to set the value of the global `event_scheduler' system variable. This requires the `SUPER' privilege. MySQL 5.1.6 introduces a privilege governing the creation, modification, and deletion of events, the `EVENT' privilege. This privilege can be bestowed using *Note `GRANT': grant. For example, this *Note `GRANT': grant. statement confers the `EVENT' privilege for the schema named `myschema' on the user `jon@ghidora': GRANT EVENT ON myschema.* TO jon@ghidora; (We assume that this user account already exists, and that we wish for it to remain unchanged otherwise.) To grant this same user the `EVENT' privilege on all schemas, use the following statement: GRANT EVENT ON *.* TO jon@ghidora; The `EVENT' privilege has global or schema-level scope. Therefore, trying to grant it on a single table results in an error as shown: mysql> GRANT EVENT ON myschema.mytable TO jon@ghidora; `ERROR 1144 (42000): Illegal GRANT/REVOKE command; please consult the manual to see which privileges can be used' It is important to understand that an event is executed with the privileges of its definer, and that it cannot perform any actions for which its definer does not have the requisite privileges. For example, suppose that `jon@ghidora' has the `EVENT' privilege for `myschema'. Suppose also that this user has the `SELECT' privilege for `myschema', but no other privileges for this schema. It is possible for `jon@ghidora' to create a new event such as this one: CREATE EVENT e_store_ts ON SCHEDULE EVERY 10 SECOND DO INSERT INTO myschema.mytable VALUES (UNIX_TIMESTAMP()); The user waits for a minute or so, and then performs a `SELECT * FROM mytable;' query, expecting to see several new rows in the table. Instead, the table is empty. Since the user does not have the `INSERT' privilege for the table in question, the event has no effect. If you inspect the MySQL error log (`HOSTNAME.err'), you can see that the event is executing, but the action it is attempting to perform fails, as indicated by `RetCode=0': 060209 22:39:44 [Note] EVEX EXECUTING event newdb.e [EXPR:10] 060209 22:39:44 [Note] EVEX EXECUTED event newdb.e [EXPR:10]. RetCode=0 060209 22:39:54 [Note] EVEX EXECUTING event newdb.e [EXPR:10] 060209 22:39:54 [Note] EVEX EXECUTED event newdb.e [EXPR:10]. RetCode=0 060209 22:40:04 [Note] EVEX EXECUTING event newdb.e [EXPR:10] 060209 22:40:04 [Note] EVEX EXECUTED event newdb.e [EXPR:10]. RetCode=0 Since this user very likely does not have access to the error log, it is possible to verify whether the event's action statement is valid by executing it directly: mysql> INSERT INTO myschema.mytable VALUES (UNIX_TIMESTAMP()); `ERROR 1142 (42000): INSERT command denied to user 'jon'@'ghidora' for table 'mytable'' Inspection of the *Note `INFORMATION_SCHEMA.EVENTS': events-table. table shows that `e_store_ts' exists and is enabled, but its `LAST_EXECUTED' column is `NULL': mysql> SELECT * FROM INFORMATION_SCHEMA.EVENTS > WHERE EVENT_NAME='e_store_ts' > AND EVENT_SCHEMA='myschema'\G *************************** 1. row *************************** EVENT_CATALOG: NULL EVENT_SCHEMA: myschema EVENT_NAME: e_store_ts DEFINER: jon@ghidora EVENT_BODY: SQL EVENT_DEFINITION: INSERT INTO myschema.mytable VALUES (UNIX_TIMESTAMP()) EVENT_TYPE: RECURRING EXECUTE_AT: NULL INTERVAL_VALUE: 5 INTERVAL_FIELD: SECOND SQL_MODE: NULL STARTS: 0000-00-00 00:00:00 ENDS: 0000-00-00 00:00:00 STATUS: ENABLED ON_COMPLETION: NOT PRESERVE CREATED: 2006-02-09 22:36:06 LAST_ALTERED: 2006-02-09 22:36:06 LAST_EXECUTED: NULL EVENT_COMMENT: 1 row in set (0.00 sec) *Note*: Prior to MySQL 5.1.12, there was no `EVENT_DEFINITION' column, and `EVENT_BODY' contained the SQL statement or statements to be executed. See *Note events-table::, for more information. To rescind the `EVENT' privilege, use the *Note `REVOKE': revoke. statement. In this example, the `EVENT' privilege on the schema `myschema' is removed from the `jon@ghidora' user account: REVOKE EVENT ON myschema.* FROM jon@ghidora; *Important*: Revoking the `EVENT' privilege from a user does not delete or disable any events that may have been created by that user. An event is not migrated or dropped as a result of renaming or dropping the user who created it. Suppose that the user `jon@ghidora' has been granted the `EVENT' and `INSERT' privileges on the `myschema' schema. This user then creates the following event: CREATE EVENT e_insert ON SCHEDULE EVERY 7 SECOND DO INSERT INTO myschema.mytable; After this event has been created, `root' revokes the `EVENT' privilege for `jon@ghidora'. However, `e_insert' continues to execute, inserting a new row into `mytable' each seven seconds. The same would be true if `root' had issued either of these statements: * `DROP USER jon@ghidora;' * `RENAME USER jon@ghidora TO someotherguy@ghidora;' You can verify that this is true by examining the `mysql.event' table (discussed later in this section) or the *Note `INFORMATION_SCHEMA.EVENTS': events-table. table (see *Note events-table::) before and after issuing a *Note `DROP USER': drop-user. or *Note `RENAME USER': rename-user. statement. Event definitions are stored in the `mysql.event' table, which was added in MySQL 5.1.6. To drop an event created by another user account, the MySQL `root' user (or another user with the necessary privileges) can delete rows from this table. For example, to remove the event `e_insert' shown previously, `root' can use the following statement: DELETE FROM mysql.event WHERE db = 'myschema' AND definer = 'jon@ghidora' AND name = 'e_insert'; It is very important to match the event name, database schema name, and user account when deleting rows from the `mysql.event' table. This is because the same user can create different events of the same name in different schemas. *Note*: The namespace for scheduled events changed in MySQL 5.1.12. Prior to that MySQL version, different users could create different events having the same name in the same database; in MySQL 5.1.12 and later, that is no longer the case. When upgrading to MySQL 5.1.12 or later from MySQL 5.1.11 or earlier, it is extremely important to make sure that no events in the same database share the same name, _prior to performing the upgrade_. Users' `EVENT' privileges are stored in the `Event_priv' columns of the `mysql.user' and `mysql.db' tables. In both cases, this column holds one of the values '`Y'' or '`N''. '`N'' is the default. `mysql.user.Event_priv' is set to '`Y'' for a given user only if that user has the global `EVENT' privilege (that is, if the privilege was bestowed using `GRANT EVENT ON *.*'). For a schema-level `EVENT' privilege, *Note `GRANT': grant. creates a row in `mysql.db' and sets that row's `Db' column to the name of the schema, the `User' column to the name of the user, and the `Event_priv' column to '`Y''. There should never be any need to manipulate these tables directly, since the *Note `GRANT EVENT': grant. and `REVOKE EVENT' statements perform the required operations on them. MySQL 5.1.6 introduces five status variables providing counts of event-related operations (but _not_ of statements executed by events; see *Note stored-program-restrictions::). These are: * `Com_create_event': The number of *Note `CREATE EVENT': create-event. statements executed since the last server restart. * `Com_alter_event': The number of *Note `ALTER EVENT': alter-event. statements executed since the last server restart. * `Com_drop_event': The number of *Note `DROP EVENT': drop-event. statements executed since the last server restart. * `Com_show_create_event': The number of *Note `SHOW CREATE EVENT': show-create-event. statements executed since the last server restart. * `Com_show_events': The number of *Note `SHOW EVENTS': show-events. statements executed since the last server restart. You can view current values for all of these at one time by running the statement `SHOW STATUS LIKE '%event%';'.  File: manual.info, Node: views, Next: stored-programs-security, Prev: events, Up: stored-programs-views 19.5 Using Views ================ * Menu: * view-syntax:: View Syntax * view-algorithms:: View Processing Algorithms * view-updatability:: Updatable and Insertable Views * view-metadata:: View Metadata Views (including updatable views) are available in MySQL Server 5.1. Views are stored queries that when invoked produce a result set. A view acts as a virtual table. To use views if you have upgraded to MySQL 5.1 from an older release that did not support views, you should upgrade your grant tables so that they contain the view-related privileges. See *Note mysql-upgrade::. The following discussion describes the syntax for creating and dropping views, and shows some examples of how to use them. * Additional Resources * * You may find the Views User Forum (http://forums.mysql.com/list.php?100) of use when working with views. * For answers to some commonly asked questions regarding views in MySQL, see *Note faqs-views::. * There are some restrictions on the use of views; see *Note view-restrictions::.  File: manual.info, Node: view-syntax, Next: view-algorithms, Prev: views, Up: views 19.5.1 View Syntax ------------------ The *Note `CREATE VIEW': create-view. statement creates a new view (see *Note create-view::). To alter the definition of a view or drop a view, use *Note `ALTER VIEW': alter-view. (see *Note alter-view::), or *Note `DROP VIEW': drop-view. (see *Note drop-view::). A view can be created from many kinds of *Note `SELECT': select. statements. It can refer to base tables or other views. It can use joins, *Note `UNION': union, and subqueries. The *Note `SELECT': select. need not even refer to any tables. The following example defines a view that selects two columns from another table, as well as an expression calculated from those columns: mysql> CREATE TABLE t (qty INT, price INT); mysql> INSERT INTO t VALUES(3, 50), (5, 60); mysql> CREATE VIEW v AS SELECT qty, price, qty*price AS value FROM t; mysql> SELECT * FROM v; +------+-------+-------+ | qty | price | value | +------+-------+-------+ | 3 | 50 | 150 | | 5 | 60 | 300 | +------+-------+-------+ mysql> SELECT * FROM v WHERE qty = 5; +------+-------+-------+ | qty | price | value | +------+-------+-------+ | 5 | 60 | 300 | +------+-------+-------+  File: manual.info, Node: view-algorithms, Next: view-updatability, Prev: view-syntax, Up: views 19.5.2 View Processing Algorithms --------------------------------- The optional `ALGORITHM' clause for *Note `CREATE VIEW': create-view. or *Note `ALTER VIEW': alter-view. is a MySQL extension to standard SQL. It affects how MySQL processes the view. `ALGORITHM' takes three values: `MERGE', `TEMPTABLE', or `UNDEFINED'. The default algorithm is `UNDEFINED' if no `ALGORITHM' clause is present. For `MERGE', the text of a statement that refers to the view and the view definition are merged such that parts of the view definition replace corresponding parts of the statement. For `TEMPTABLE', the results from the view are retrieved into a temporary table, which then is used to execute the statement. For `UNDEFINED', MySQL chooses which algorithm to use. It prefers `MERGE' over `TEMPTABLE' if possible, because `MERGE' is usually more efficient and because a view cannot be updatable if a temporary table is used. A reason to choose `TEMPTABLE' explicitly is that locks can be released on underlying tables after the temporary table has been created and before it is used to finish processing the statement. This might result in quicker lock release than the `MERGE' algorithm so that other clients that use the view are not blocked as long. A view algorithm can be `UNDEFINED' for three reasons: * No `ALGORITHM' clause is present in the *Note `CREATE VIEW': create-view. statement. * The *Note `CREATE VIEW': create-view. statement has an explicit `ALGORITHM = UNDEFINED' clause. * `ALGORITHM = MERGE' is specified for a view that can be processed only with a temporary table. In this case, MySQL generates a warning and sets the algorithm to `UNDEFINED'. As mentioned earlier, `MERGE' is handled by merging corresponding parts of a view definition into the statement that refers to the view. The following examples briefly illustrate how the `MERGE' algorithm works. The examples assume that there is a view `v_merge' that has this definition: CREATE ALGORITHM = MERGE VIEW v_merge (vc1, vc2) AS SELECT c1, c2 FROM t WHERE c3 > 100; Example 1: Suppose that we issue this statement: SELECT * FROM v_merge; MySQL handles the statement as follows: * `v_merge' becomes `t' * `*' becomes `vc1, vc2', which corresponds to `c1, c2' * The view `WHERE' clause is added The resulting statement to be executed becomes: SELECT c1, c2 FROM t WHERE c3 > 100; Example 2: Suppose that we issue this statement: SELECT * FROM v_merge WHERE vc1 < 100; This statement is handled similarly to the previous one, except that `vc1 < 100' becomes `c1 < 100' and the view `WHERE' clause is added to the statement `WHERE' clause using an `AND' connective (and parentheses are added to make sure the parts of the clause are executed with correct precedence). The resulting statement to be executed becomes: SELECT c1, c2 FROM t WHERE (c3 > 100) AND (c1 < 100); Effectively, the statement to be executed has a `WHERE' clause of this form: WHERE (select WHERE) AND (view WHERE) If the `MERGE' algorithm cannot be used, a temporary table must be used instead. `MERGE' cannot be used if the view contains any of the following constructs: * Aggregate functions (`SUM()', `MIN()', `MAX()', `COUNT()', and so forth) * `DISTINCT' * `GROUP BY' * `HAVING' * `LIMIT' * *Note `UNION': union. or *Note `UNION ALL': union. * Subquery in the select list * Refers only to literal values (in this case, there is no underlying table)  File: manual.info, Node: view-updatability, Next: view-metadata, Prev: view-algorithms, Up: views 19.5.3 Updatable and Insertable Views ------------------------------------- Some views are updatable. That is, you can use them in statements such as *Note `UPDATE': update, *Note `DELETE': delete, or *Note `INSERT': insert. to update the contents of the underlying table. For a view to be updatable, there must be a one-to-one relationship between the rows in the view and the rows in the underlying table. There are also certain other constructs that make a view nonupdatable. To be more specific, a view is not updatable if it contains any of the following: * Aggregate functions (`SUM()', `MIN()', `MAX()', `COUNT()', and so forth) * `DISTINCT' * `GROUP BY' * `HAVING' * *Note `UNION': union. or *Note `UNION ALL': union. * Subquery in the select list * Certain joins (see additional join discussion later in this section) * Nonupdatable view in the `FROM' clause * A subquery in the `WHERE' clause that refers to a table in the `FROM' clause * Refers only to literal values (in this case, there is no underlying table to update) * Uses `ALGORITHM = TEMPTABLE' (use of a temporary table always makes a view nonupdatable) * Multiple references to any column of a base table. With respect to insertability (being updatable with *Note `INSERT': insert. statements), an updatable view is insertable if it also satisfies these additional requirements for the view columns: * There must be no duplicate view column names. * The view must contain all columns in the base table that do not have a default value. * The view columns must be simple column references and not derived columns. A derived column is one that is not a simple column reference but is derived from an expression. These are examples of derived columns: 3.14159 col1 + 3 UPPER(col2) col3 / col4 (SUBQUERY) A view that has a mix of simple column references and derived columns is not insertable, but it can be updatable if you update only those columns that are not derived. Consider this view: CREATE VIEW v AS SELECT col1, 1 AS col2 FROM t; This view is not insertable because `col2' is derived from an expression. But it is updatable if the update does not try to update `col2'. This update is permissible: UPDATE v SET col1 = 0; This update is not permissible because it attempts to update a derived column: UPDATE v SET col2 = 0; It is sometimes possible for a multiple-table view to be updatable, assuming that it can be processed with the `MERGE' algorithm. For this to work, the view must use an inner join (not an outer join or a *Note `UNION': union.). Also, only a single table in the view definition can be updated, so the `SET' clause must name only columns from one of the tables in the view. Views that use *Note `UNION ALL': union. are not permitted even though they might be theoretically updatable, because the implementation uses temporary tables to process them. For a multiple-table updatable view, *Note `INSERT': insert. can work if it inserts into a single table. *Note `DELETE': delete. is not supported. *Note `INSERT DELAYED': insert-delayed. is not supported for views. If a table contains an `AUTO_INCREMENT' column, inserting into an insertable view on the table that does not include the `AUTO_INCREMENT' column does not change the value of `LAST_INSERT_ID()', because the side effects of inserting default values into columns not part of the view should not be visible. The `WITH CHECK OPTION' clause can be given for an updatable view to prevent inserts or updates to rows except those for which the `WHERE' clause in the SELECT_STATEMENT is true. In a `WITH CHECK OPTION' clause for an updatable view, the `LOCAL' and `CASCADED' keywords determine the scope of check testing when the view is defined in terms of another view. The `LOCAL' keyword restricts the `CHECK OPTION' only to the view being defined. `CASCADED' causes the checks for underlying views to be evaluated as well. When neither keyword is given, the default is `CASCADED'. Consider the definitions for the following table and set of views: mysql> CREATE TABLE t1 (a INT); mysql> CREATE VIEW v1 AS SELECT * FROM t1 WHERE a < 2 -> WITH CHECK OPTION; mysql> CREATE VIEW v2 AS SELECT * FROM v1 WHERE a > 0 -> WITH LOCAL CHECK OPTION; mysql> CREATE VIEW v3 AS SELECT * FROM v1 WHERE a > 0 -> WITH CASCADED CHECK OPTION; Here the `v2' and `v3' views are defined in terms of another view, `v1'. `v2' has a `LOCAL' check option, so inserts are tested only against the `v2' check. `v3' has a `CASCADED' check option, so inserts are tested not only against its own check, but against those of underlying views. The following statements illustrate these differences: mysql> INSERT INTO v2 VALUES (2); Query OK, 1 row affected (0.00 sec) mysql> INSERT INTO v3 VALUES (2); ERROR 1369 (HY000): CHECK OPTION failed 'test.v3' MySQL sets a flag, called the view updatability flag, at *Note `CREATE VIEW': create-view. time. The flag is set to `YES' (true) if *Note `UPDATE': update. and *Note `DELETE': delete. (and similar operations) are legal for the view. Otherwise, the flag is set to `NO' (false). The `IS_UPDATABLE' column in the *Note `INFORMATION_SCHEMA.VIEWS': views-table. table displays the status of this flag. It means that the server always knows whether a view is updatable. If the view is not updatable, statements such *Note `UPDATE': update, *Note `DELETE': delete, and *Note `INSERT': insert. are illegal and will be rejected. (Note that even if a view is updatable, it might not be possible to insert into it, as described elsewhere in this section.) The updatability of views may be affected by the value of the `updatable_views_with_limit' system variable. See *Note server-system-variables::.  File: manual.info, Node: view-metadata, Prev: view-updatability, Up: views 19.5.4 View Metadata -------------------- Metadata about views can be obtained as follows: * Query the *Note `VIEWS': views-table. table of the `INFORMATION_SCHEMA' database. See *Note views-table::. * Use the *Note `SHOW CREATE VIEW': show-create-view. statement. See *Note show-create-view::.  File: manual.info, Node: stored-programs-security, Next: stored-programs-logging, Prev: views, Up: stored-programs-views 19.6 Access Control for Stored Programs and Views ================================================= Stored programs and views are defined prior to use and, when referenced, execute within a security context that determines their privileges. These privileges are controlled by their `DEFINER' attribute, and, if there is one, their `SQL SECURITY' characteristic. All stored programs (procedures, functions, triggers, and events) and views can have a `DEFINER' attribute that names a MySQL account. If the `DEFINER' attribute is omitted from a stored program or view definition, the default account is the user who creates the object. In addition, stored routines (procedures and functions) and views can have a `SQL SECURITY' characteristic with a value of `DEFINER' or `INVOKER' to specify whether the object executes in definer or invoker context. If the `SQL SECURITY' characteristic is omitted, the default is definer context. Triggers and events have no `SQL SECURITY' characteristic and always execute in definer context. The server invokes these objects automatically as necessary, so there is no invoking user. Definer and invoker security contexts differ as follows: * A stored program or view that executes in definer security context executes with the privileges of the account named by its `DEFINER' attribute. These privileges may be entirely different from those of the invoking user. The invoker must have appropriate privileges to reference the object (for example, `EXECUTE' to call a stored procedure or `SELECT' to select from a view), but when the object executes, the invoker's privileges are ignored and only the `DEFINER' account privileges matter. If this account has few privileges, the object is correspondingly limited in the operations it can perform. If the `DEFINER' account is highly privileged (such as a `root' account), the object can perform powerful operations _no matter who invokes it._ * A stored routine or view that executes in invoker security context can perform only operations for which the invoker has privileges. The `DEFINER' attribute can be specified but has no effect for objects that execute in invoker context. Consider the following stored procedure: CREATE DEFINER = 'admin'@'localhost' PROCEDURE p1() SQL SECURITY DEFINER BEGIN UPDATE t1 SET counter = counter + 1; END; Any user who has the `EXECUTE' privilege for `p1' can invoke it with a *Note `CALL': call. statement. However, when `p1' executes, it does so in `DEFINER' security context and thus executes with the privileges of `'admin'@'localhost'', the account named in the `DEFINER' attribute. This account must have the `EXECUTE' privilege for `p1' as well as the `UPDATE' privilege for the table `t1'. Otherwise, the procedure fails. Now consider this stored procedure, which is identical to `p1' except that its `SQL SECURITY' characteristic is `INVOKER': CREATE DEFINER = 'admin'@'localhost' PROCEDURE p2() SQL SECURITY INVOKER BEGIN UPDATE t1 SET counter = counter + 1; END; `p2', unlike `p1', executes in `INVOKER' security context. The `DEFINER' attribute is irrelevant and `p2' executes with the privileges of the invoking user. `p2' fails if the invoker lacks the `EXECUTE' privilege for `p2' or the `UPDATE' privilege for the table `t1'. MySQL uses the following rules to control which accounts a user can specify in an object `DEFINER' attribute: * You can specify a `DEFINER' value other than your own account only if you have the `SUPER' privilege. * If you do not have the `SUPER' privilege, the only legal user value is your own account, either specified literally or by using `CURRENT_USER'. You cannot set the definer to some other account. To minimize the risk potential for stored program and view creation and use, follow these guidelines: * For a stored routine or view, use `SQL SECURITY INVOKER' in the object definition when possible so that it can be used only by users with permissions appropriate for the operations performed by the object. * If you create definer-context stored programs or views while using an account that has the `SUPER' privilege, specify an explicit `DEFINER' attribute that names an account possessing only the privileges required for the operations performed by the object. Specify a highly privileged `DEFINER' account only when absolutely necessary. * Administrators can prevent users from specifying highly privileged `DEFINER' accounts by not granting them the `SUPER' privilege. * Definer-context objects should be written keeping in mind that they may be able to access data for which the invoking user has no privileges. In some cases, you can prevent reference to these objects by not granting unauthorized users particular privileges: * A stored procedure or function cannot be referenced by a user who does not have the `EXECUTE' privilege for it. * A view cannot be referenced by a user who does not have the appropriate privilege for it (`SELECT' to select from it, `INSERT' to insert into it, and so forth). However, no such control exists for triggers because users do not reference them directly. A trigger always executes in `DEFINER' context and is activated by access to the table with which it is associated, even ordinary table accesses by users with no special privileges. If the `DEFINER' account is highly privileged, the trigger can perform sensitive or dangerous operations. This remains true if the `SUPER' and `TRIGGER' privileges needed to create the trigger are revoked from the account of the user who created it. Administrators should be especially careful about granting users that combination of privileges.  File: manual.info, Node: stored-programs-logging, Prev: stored-programs-security, Up: stored-programs-views 19.7 Binary Logging of Stored Programs ====================================== The binary log contains information about SQL statements that modify database contents. This information is stored in the form of `events' that describe the modifications. The binary log has two important purposes: * For replication, the binary log is used on master replication servers as a record of the statements to be sent to slave servers. The master server sends the events contained in its binary log to its slaves, which execute those events to make the same data changes that were made on the master. See *Note replication-implementation::. * Certain data recovery operations require use of the binary log. After a backup file has been restored, the events in the binary log that were recorded after the backup was made are re-executed. These events bring databases up to date from the point of the backup. See *Note recovery-from-backups::. However, there are certain binary logging issues that apply with respect to stored programs (stored procedures and functions, triggers, and events), if logging occurs at the statement level: * In some cases, it is possible that a statement will affect different sets of rows on a master and a slave. * Replicated statements executed on a slave are processed by the slave SQL thread, which has full privileges. It is possible for a procedure to follow different execution paths on master and slave servers, so a user can write a routine containing a dangerous statement that will execute only on the slave where it is processed by a thread that has full privileges. * If a stored program that modifies data is nondeterministic, it is not repeatable. This can result in different data on a master and slave, or cause restored data to differ from the original data. This section describes how MySQL 5.1 handles binary logging for stored programs. It states the current conditions that the implementation places on the use of stored programs, and what you can do to avoid problems. It also provides additional information about the reasons for these conditions. In general, the issues described here result when binary logging occurs at the SQL statement level. If you use row-based binary logging, the log contains changes made to individual rows as a result of executing SQL statements. When routines or triggers execute, row changes are logged, not the statements that make the changes. For stored procedures, this means that the *Note `CALL': call. statement is not logged. For stored functions, row changes made within the function are logged, not the function invocation. For triggers, row changes made by the trigger are logged. On the slave side, only the row changes are seen, not the stored program invocation. For general information about row-based logging, see *Note replication-formats::. Unless noted otherwise, the remarks here assume that you have enabled binary logging by starting the server with the `--log-bin' option. (See *Note binary-log::.) If the binary log is not enabled, replication is not possible, nor is the binary log available for data recovery. The current conditions on the use of stored functions in MySQL 5.1 can be summarized as follows. These conditions do not apply to stored procedures or Event Scheduler events and they do not apply unless binary logging is enabled. * To create or alter a stored function, you must have the `SUPER' privilege, in addition to the `CREATE ROUTINE' or `ALTER ROUTINE' privilege that is normally required. (Depending on the `DEFINER' value in the function definition, `SUPER' might be required regardless of whether binary logging is enabled. See *Note create-procedure::.) * When you create a stored function, you must declare either that it is deterministic or that it does not modify data. Otherwise, it may be unsafe for data recovery or replication. By default, for a *Note `CREATE FUNCTION': create-function. statement to be accepted, at least one of `DETERMINISTIC', `NO SQL', or `READS SQL DATA' must be specified explicitly. Otherwise an error occurs: ERROR 1418 (HY000): This function has none of DETERMINISTIC, NO SQL, or READS SQL DATA in its declaration and binary logging is enabled (you *might* want to use the less safe log_bin_trust_function_creators variable) This function is deterministic (and does not modify data), so it is safe: CREATE FUNCTION f1(i INT) RETURNS INT DETERMINISTIC READS SQL DATA BEGIN RETURN i; END; This function uses `UUID()', which is not deterministic, so the function also is not deterministic and is not safe: CREATE FUNCTION f2() RETURNS CHAR(36) CHARACTER SET utf8 BEGIN RETURN UUID(); END; This function modifies data, so it may not be safe: CREATE FUNCTION f3(p_id INT) RETURNS INT BEGIN UPDATE t SET modtime = NOW() WHERE id = p_id; RETURN ROW_COUNT(); END; Assessment of the nature of a function is based on the `honesty' of the creator: MySQL does not check that a function declared `DETERMINISTIC' is free of statements that produce nondeterministic results. * Although it is possible to create a deterministic stored function without specifying `DETERMINISTIC', you cannot as of MySQL 5.1.15 execute this function using statement-based binary logging. To execute such a function, you must use row-based or mixed binary logging. Alternatively, if you explicitly specify `DETERMINISTIC' in the function definition, you can use any kind of logging, including statement-based logging. * To relax the preceding conditions on function creation (that you must have the `SUPER' privilege and that a function must be declared deterministic or to not modify data), set the global `log_bin_trust_function_creators' system variable to 1. By default, this variable has a value of 0, but you can change it like this: mysql> SET GLOBAL log_bin_trust_function_creators = 1; You can also set this variable by using the `--log-bin-trust-function-creators=1' option when starting the server. If binary logging is not enabled, `log_bin_trust_function_creators' does not apply. `SUPER' is not required for function creation unless, as described previously, the `DEFINER' value in the function definition requires it. * For information about built-in functions that may be unsafe for replication (and thus cause stored functions that use them to be unsafe as well), see *Note replication-features::. Triggers are similar to stored functions, so the preceding remarks regarding functions also apply to triggers with the following exception: *Note `CREATE TRIGGER': create-trigger. does not have an optional `DETERMINISTIC' characteristic, so triggers are assumed to be always deterministic. However, this assumption might in some cases be invalid. For example, the `UUID()' function is nondeterministic (and does not replicate). You should be careful about using such functions in triggers. Triggers can update tables, so error messages similar to those for stored functions occur with *Note `CREATE TRIGGER': create-trigger. if you do not have the required privileges. On the slave side, the slave uses the trigger `DEFINER' attribute to determine which user is considered to be the creator of the trigger. The rest of this section provides additional detail about the logging implementation and its implications. You need not read it unless you are interested in the background on the rationale for the current logging-related conditions on stored routine use. This discussion applies only for statement-based logging, and not for row-based logging, with the exception of the first item: `CREATE' and `DROP' statements are logged as statements regardless of the logging mode. * The server writes *Note `CREATE EVENT': create-event, *Note `CREATE PROCEDURE': create-procedure, *Note `CREATE FUNCTION': create-function, *Note `ALTER EVENT': alter-event, *Note `ALTER PROCEDURE': alter-procedure, *Note `ALTER FUNCTION': alter-function, *Note `DROP EVENT': drop-event, *Note `DROP PROCEDURE': drop-procedure, and *Note `DROP FUNCTION': drop-function. statements to the binary log. * A stored function invocation is logged as a *Note `SELECT': select. statement if the function changes data and occurs within a statement that would not otherwise be logged. This prevents nonreplication of data changes that result from use of stored functions in nonlogged statements. For example, *Note `SELECT': select. statements are not written to the binary log, but a *Note `SELECT': select. might invoke a stored function that makes changes. To handle this, a `SELECT FUNC_NAME()' statement is written to the binary log when the given function makes a change. Suppose that the following statements are executed on the master: CREATE FUNCTION f1(a INT) RETURNS INT BEGIN IF (a < 3) THEN INSERT INTO t2 VALUES (a); END IF; RETURN 0; END; CREATE TABLE t1 (a INT); INSERT INTO t1 VALUES (1),(2),(3); SELECT f1(a) FROM t1; When the *Note `SELECT': select. statement executes, the function `f1()' is invoked three times. Two of those invocations insert a row, and MySQL logs a *Note `SELECT': select. statement for each of them. That is, MySQL writes the following statements to the binary log: SELECT f1(1); SELECT f1(2); The server also logs a *Note `SELECT': select. statement for a stored function invocation when the function invokes a stored procedure that causes an error. In this case, the server writes the *Note `SELECT': select. statement to the log along with the expected error code. On the slave, if the same error occurs, that is the expected result and replication continues. Otherwise, replication stops. Note: Before MySQL 5.1.7, you will see these `SELECT FUNC_NAME()' statements logged as `DO FUNC_NAME()'. The change to *Note `SELECT': select. was made because use of *Note `DO': do. was found to yield insufficient control over error code checking. * Logging stored function invocations rather than the statements executed by a function has a security implication for replication, which arises from two factors: * It is possible for a function to follow different execution paths on master and slave servers. * Statements executed on a slave are processed by the slave SQL thread which has full privileges. The implication is that although a user must have the `CREATE ROUTINE' privilege to create a function, the user can write a function containing a dangerous statement that will execute only on the slave where it is processed by a thread that has full privileges. For example, if the master and slave servers have server ID values of 1 and 2, respectively, a user on the master server could create and invoke an unsafe function `unsafe_func()' as follows: mysql> delimiter // mysql> CREATE FUNCTION unsafe_func () RETURNS INT -> BEGIN -> IF @@server_id=2 THEN DANGEROUS_STATEMENT; END IF; -> RETURN 1; -> END; -> // mysql> delimiter ; mysql> INSERT INTO t VALUES(unsafe_func()); The *Note `CREATE FUNCTION': create-function. and *Note `INSERT': insert. statements are written to the binary log, so the slave will execute them. Because the slave SQL thread has full privileges, it will execute the dangerous statement. Thus, the function invocation has different effects on the master and slave and is not replication-safe. To guard against this danger for servers that have binary logging enabled, stored function creators must have the `SUPER' privilege, in addition to the usual `CREATE ROUTINE' privilege that is required. Similarly, to use *Note `ALTER FUNCTION': alter-function, you must have the `SUPER' privilege in addition to the `ALTER ROUTINE' privilege. Without the `SUPER' privilege, an error will occur: ERROR 1419 (HY000): You do not have the SUPER privilege and binary logging is enabled (you *might* want to use the less safe log_bin_trust_function_creators variable) If you do not want to require function creators to have the `SUPER' privilege (for example, if all users with the `CREATE ROUTINE' privilege on your system are experienced application developers), set the global `log_bin_trust_function_creators' system variable to 1. You can also set this variable by using the `--log-bin-trust-function-creators=1' option when starting the server. If binary logging is not enabled, `log_bin_trust_function_creators' does not apply. `SUPER' is not required for function creation unless, as described previously, the `DEFINER' value in the function definition requires it. * If a function that performs updates is nondeterministic, it is not repeatable. This can have two undesirable effects: * It will make a slave different from the master. * Restored data will be different from the original data. To deal with these problems, MySQL enforces the following requirement: On a master server, creation and alteration of a function is refused unless you declare the function to be deterministic or to not modify data. Two sets of function characteristics apply here: * The `DETERMINISTIC' and `NOT DETERMINISTIC' characteristics indicate whether a function always produces the same result for given inputs. The default is `NOT DETERMINISTIC' if neither characteristic is given. To declare that a function is deterministic, you must specify `DETERMINISTIC' explicitly. * The `CONTAINS SQL', `NO SQL', `READS SQL DATA', and `MODIFIES SQL DATA' characteristics provide information about whether the function reads or writes data. Either `NO SQL' or `READS SQL DATA' indicates that a function does not change data, but you must specify one of these explicitly because the default is `CONTAINS SQL' if no characteristic is given. By default, for a *Note `CREATE FUNCTION': create-function. statement to be accepted, at least one of `DETERMINISTIC', `NO SQL', or `READS SQL DATA' must be specified explicitly. Otherwise an error occurs: ERROR 1418 (HY000): This function has none of DETERMINISTIC, NO SQL, or READS SQL DATA in its declaration and binary logging is enabled (you *might* want to use the less safe log_bin_trust_function_creators variable) If you set `log_bin_trust_function_creators' to 1, the requirement that functions be deterministic or not modify data is dropped. * Stored procedure calls are logged at the statement level rather than at the *Note `CALL': call. level. That is, the server does not log the *Note `CALL': call. statement, it logs those statements within the procedure that actually execute. As a result, the same changes that occur on the master will be observed on slave servers. This prevents problems that could result from a procedure having different execution paths on different machines. In general, statements executed within a stored procedure are written to the binary log using the same rules that would apply were the statements to be executed in standalone fashion. Some special care is taken when logging procedure statements because statement execution within procedures is not quite the same as in nonprocedure context: * A statement to be logged might contain references to local procedure variables. These variables do not exist outside of stored procedure context, so a statement that refers to such a variable cannot be logged literally. Instead, each reference to a local variable is replaced by this construct for logging purposes: NAME_CONST(VAR_NAME, VAR_VALUE) VAR_NAME is the local variable name, and VAR_VALUE is a constant indicating the value that the variable has at the time the statement is logged. `NAME_CONST()' has a value of VAR_VALUE, and a `name' of VAR_NAME. Thus, if you invoke this function directly, you get a result like this: mysql> SELECT NAME_CONST('myname', 14); +--------+ | myname | +--------+ | 14 | +--------+ `NAME_CONST()' enables a logged standalone statement to be executed on a slave with the same effect as the original statement that was executed on the master within a stored procedure. The use of `NAME_CONST()' can result in a problem for *Note `CREATE TABLE ... SELECT': create-table. statements when the source column expressions refer to local variables. Converting these references to `NAME_CONST()' expressions can result in column names that are different on the master and slave servers, or names that are too long to be legal column identifiers. A workaround is to supply aliases for columns that refer to local variables. Consider this statement when `myvar' has a value of 1: CREATE TABLE t1 SELECT myvar; That will be rewritten as follows: CREATE TABLE t1 SELECT NAME_CONST(myvar, 1); To ensure that the master and slave tables have the same column names, write the statement like this: CREATE TABLE t1 SELECT myvar AS myvar; The rewritten statement becomes: CREATE TABLE t1 SELECT NAME_CONST(myvar, 1) AS myvar; * A statement to be logged might contain references to user-defined variables. To handle this, MySQL writes a *Note `SET': set-option. statement to the binary log to make sure that the variable exists on the slave with the same value as on the master. For example, if a statement refers to a variable `@my_var', that statement will be preceded in the binary log by the following statement, where VALUE is the value of `@my_var' on the master: SET @my_var = VALUE; * Procedure calls can occur within a committed or rolled-back transaction. Transactional context is accounted for so that the transactional aspects of procedure execution are replicated correctly. That is, the server logs those statements within the procedure that actually execute and modify data, and also logs *Note `BEGIN': commit, *Note `COMMIT': commit, and *Note `ROLLBACK': commit. statements as necessary. For example, if a procedure updates only transactional tables and is executed within a transaction that is rolled back, those updates are not logged. If the procedure occurs within a committed transaction, *Note `BEGIN': commit. and *Note `COMMIT': commit. statements are logged with the updates. For a procedure that executes within a rolled-back transaction, its statements are logged using the same rules that would apply if the statements were executed in standalone fashion: * Updates to transactional tables are not logged. * Updates to nontransactional tables are logged because rollback does not cancel them. * Updates to a mix of transactional and nontransactional tables are logged surrounded by *Note `BEGIN': commit. and *Note `ROLLBACK': commit. so that slaves will make the same changes and rollbacks as on the master. * A stored procedure call is _not_ written to the binary log at the statement level if the procedure is invoked from within a stored function. In that case, the only thing logged is the statement that invokes the function (if it occurs within a statement that is logged) or a *Note `DO': do. statement (if it occurs within a statement that is not logged). For this reason, care should be exercised in the use of stored functions that invoke a procedure, even if the procedure is otherwise safe in itself.  File: manual.info, Node: information-schema, Next: connectors-apis, Prev: stored-programs-views, Up: Top 20 `INFORMATION_SCHEMA' Tables ****************************** * Menu: * schemata-table:: The `INFORMATION_SCHEMA SCHEMATA' Table * tables-table:: The `INFORMATION_SCHEMA TABLES' Table * columns-table:: The `INFORMATION_SCHEMA COLUMNS' Table * statistics-table:: The `INFORMATION_SCHEMA STATISTICS' Table * user-privileges-table:: The `INFORMATION_SCHEMA USER_PRIVILEGES' Table * schema-privileges-table:: The `INFORMATION_SCHEMA SCHEMA_PRIVILEGES' Table * table-privileges-table:: The `INFORMATION_SCHEMA TABLE_PRIVILEGES' Table * column-privileges-table:: The `INFORMATION_SCHEMA COLUMN_PRIVILEGES' Table * character-sets-table:: The `INFORMATION_SCHEMA CHARACTER_SETS' Table * collations-table:: The `INFORMATION_SCHEMA COLLATIONS' Table * collation-character-set-applicability-table:: The `INFORMATION_SCHEMA COLLATION_CHARACTER_SET_APPLICABILITY' Table * table-constraints-table:: The `INFORMATION_SCHEMA TABLE_CONSTRAINTS' Table * key-column-usage-table:: The `INFORMATION_SCHEMA KEY_COLUMN_USAGE' Table * routines-table:: The `INFORMATION_SCHEMA ROUTINES' Table * views-table:: The `INFORMATION_SCHEMA VIEWS' Table * triggers-table:: The `INFORMATION_SCHEMA TRIGGERS' Table * plugins-table:: The `INFORMATION_SCHEMA PLUGINS' Table * engines-table:: The `INFORMATION_SCHEMA ENGINES' Table * partitions-table:: The `INFORMATION_SCHEMA PARTITIONS' Table * events-table:: The `INFORMATION_SCHEMA EVENTS' Table * files-table:: The `INFORMATION_SCHEMA FILES' Table * processlist-table:: The `INFORMATION_SCHEMA PROCESSLIST' Table * referential-constraints-table:: The `INFORMATION_SCHEMA REFERENTIAL_CONSTRAINTS' Table * status-table:: The `INFORMATION_SCHEMA GLOBAL_STATUS' and `SESSION_STATUS' Tables * variables-table:: The `INFORMATION_SCHEMA GLOBAL_VARIABLES' and `SESSION_VARIABLES' Tables * profiling-table:: The `INFORMATION_SCHEMA PROFILING' Table * other-information-schema-tables:: Other `INFORMATION_SCHEMA' Tables * extended-show:: Extensions to `SHOW' Statements `INFORMATION_SCHEMA' provides access to database metadata. _Metadata_ is data about the data, such as the name of a database or table, the data type of a column, or access privileges. Other terms that sometimes are used for this information are _data dictionary_ and _system catalog_. `INFORMATION_SCHEMA' is the information database, the place that stores information about all the other databases that the MySQL server maintains. Inside `INFORMATION_SCHEMA' there are several read-only tables. They are actually views, not base tables, so there are no files associated with them. In effect, we have a database named `INFORMATION_SCHEMA', although the server does not create a database directory with that name. It is possible to select `INFORMATION_SCHEMA' as the default database with a *Note `USE': use. statement, but it is possible only to read the contents of tables. You cannot insert into them, update them, or delete from them. The fact that `INFORMATION_SCHEMA' tables are actually views also means that you cannot set triggers on them. See *Note triggers::. Here is an example of a statement that retrieves information from `INFORMATION_SCHEMA': mysql> SELECT table_name, table_type, engine -> FROM information_schema.tables -> WHERE table_schema = 'db5' -> ORDER BY table_name DESC; +------------+------------+--------+ | table_name | table_type | engine | +------------+------------+--------+ | v56 | VIEW | NULL | | v3 | VIEW | NULL | | v2 | VIEW | NULL | | v | VIEW | NULL | | tables | BASE TABLE | MyISAM | | t7 | BASE TABLE | MyISAM | | t3 | BASE TABLE | MyISAM | | t2 | BASE TABLE | MyISAM | | t | BASE TABLE | MyISAM | | pk | BASE TABLE | InnoDB | | loop | BASE TABLE | MyISAM | | kurs | BASE TABLE | MyISAM | | k | BASE TABLE | MyISAM | | into | BASE TABLE | MyISAM | | goto | BASE TABLE | MyISAM | | fk2 | BASE TABLE | InnoDB | | fk | BASE TABLE | InnoDB | +------------+------------+--------+ 17 rows in set (0.01 sec) Explanation: The statement requests a list of all the tables in database `db5', in reverse alphabetic order, showing just three pieces of information: the name of the table, its type, and its storage engine. The definition for character columns (for example, `TABLES.TABLE_NAME') is generally `VARCHAR(N) CHARACTER SET utf8' where N is at least 64. MySQL uses the default collation for this character set (`utf8_general_ci') for all searches, sorts, comparisons, and other string operations on such columns. However, searches in `INFORMATION_SCHEMA' string columns are also affected by file system case sensitivity. For more information, see *Note charset-collation-information-schema::. Each MySQL user has the right to access these tables, but can see only the rows in the tables that correspond to objects for which the user has the proper access privileges. In some cases (for example, the `ROUTINE_DEFINITION' column in the *Note `INFORMATION_SCHEMA.ROUTINES': routines-table. table), users who have insufficient privileges will see `NULL'. The `SELECT ... FROM INFORMATION_SCHEMA' statement is intended as a more consistent way to provide access to the information provided by the various *Note `SHOW': show. statements that MySQL supports (*Note `SHOW DATABASES': show-databases, *Note `SHOW TABLES': show-tables, and so forth). Using *Note `SELECT': select. has these advantages, compared to *Note `SHOW': show.: * It conforms to Codd's rules. That is, all access is done on tables. * Nobody needs to learn a new statement syntax. Because they already know how *Note `SELECT': select. works, they only need to learn the object names. * The implementor need not worry about adding keywords. * There are millions of possible output variations, instead of just one. This provides more flexibility for applications that have varying requirements about what metadata they need. * Migration is easier because every other DBMS does it this way. However, because *Note `SHOW': show. is popular and because it might be confusing were it to disappear, the advantages of conventional syntax are not a sufficient reason to eliminate *Note `SHOW': show. In fact, along with the implementation of `INFORMATION_SCHEMA', there are enhancements to *Note `SHOW': show. as well. These are described in *Note extended-show::. There is no difference between the privileges required for *Note `SHOW': show. statements and those required to select information from `INFORMATION_SCHEMA'. In either case, you have to have some privilege on an object in order to see information about it. `INFORMATION_SCHEMA' queries that search for information from more than one database might take a long time and impact performance. To check the efficiency of a query, you can use *Note `EXPLAIN': explain. For information about *Note `EXPLAIN': explain. output that is specific to interpreting the cost of `INFORMATION_SCHEMA' queries, see *Note information-schema-optimization::. The implementation for the `INFORMATION_SCHEMA' table structures in MySQL follows the ANSI/ISO SQL:2003 standard Part 11 `Schemata'. Our intent is approximate compliance with SQL:2003 core feature F021 `Basic information schema'. Users of SQL Server 2000 (which also follows the standard) may notice a strong similarity. However, MySQL has omitted many columns that are not relevant for our implementation, and added columns that are MySQL-specific. One such column is the `ENGINE' column in the *Note `INFORMATION_SCHEMA.TABLES': tables-table. table. Although other DBMSs use a variety of names, like `syscat' or `system', the standard name is `INFORMATION_SCHEMA'. The following sections describe each of the tables and columns that are in `INFORMATION_SCHEMA'. For each column, there are three pieces of information: * ``INFORMATION_SCHEMA' Name' indicates the name for the column in the `INFORMATION_SCHEMA' table. This corresponds to the standard SQL name unless the `Remarks' field says `MySQL extension.' * `*Note `SHOW': show. Name' indicates the equivalent field name in the closest *Note `SHOW': show. statement, if there is one. * `Remarks' provides additional information where applicable. If this field is `NULL', it means that the value of the column is always `NULL'. If this field says `MySQL extension,' the column is a MySQL extension to standard SQL. To avoid using any name that is reserved in the standard or in DB2, SQL Server, or Oracle, we changed the names of some columns marked `MySQL extension'. (For example, we changed `COLLATION' to `TABLE_COLLATION' in the *Note `TABLES': tables-table. table.) See the list of reserved words near the end of this article: `http://web.archive.org/web/20070409075643rn_1/www.dbazine.com/db2/db2-disarticles/gulutzan5'. Each section indicates what *Note `SHOW': show. statement is equivalent to a *Note `SELECT': select. that retrieves information from `INFORMATION_SCHEMA', if there is such a statement. For *Note `SHOW': show. statements that display information for the default database if you omit a `FROM DB_NAME' clause, you can often select information for the default database by adding an `AND TABLE_SCHEMA = SCHEMA()' condition to the `WHERE' clause of a query that retrieves information from an `INFORMATION_SCHEMA' table. *Note*: At present, there are some missing columns and some columns out of order. We are working on this and updating the documentation as changes are made. For answers to questions that are often asked concerning the `INFORMATION_SCHEMA' database, see *Note faqs-information-schema::.  File: manual.info, Node: schemata-table, Next: tables-table, Prev: information-schema, Up: information-schema 20.1 The `INFORMATION_SCHEMA SCHEMATA' Table ============================================ A schema is a database, so the *Note `SCHEMATA': schemata-table. table provides information about databases. `INFORMATION_SCHEMA' Name *Note `SHOW': show. Remarks Name `CATALOG_NAME' `NULL' `SCHEMA_NAME' Database `DEFAULT_CHARACTER_SET_NAME' `DEFAULT_COLLATION_NAME' `SQL_PATH' `NULL' The following statements are equivalent: SELECT SCHEMA_NAME AS `Database` FROM INFORMATION_SCHEMA.SCHEMATA [WHERE SCHEMA_NAME LIKE 'WILD'] SHOW DATABASES [LIKE 'WILD']  File: manual.info, Node: tables-table, Next: columns-table, Prev: schemata-table, Up: information-schema 20.2 The `INFORMATION_SCHEMA TABLES' Table ========================================== The *Note `TABLES': tables-table. table provides information about tables in databases. `INFORMATION_SCHEMA' Name *Note `SHOW': show. Remarks Name `TABLE_CATALOG' `NULL' `TABLE_SCHEMA' `Table_'... `TABLE_NAME' `Table_'... `TABLE_TYPE' `ENGINE' `Engine' MySQL extension `VERSION' `Version' The version number of the table's `.frm' file, MySQL extension `ROW_FORMAT' `Row_format' MySQL extension `TABLE_ROWS' `Rows' MySQL extension `AVG_ROW_LENGTH' `Avg_row_length' MySQL extension `DATA_LENGTH' `Data_length' MySQL extension `MAX_DATA_LENGTH' `Max_data_length' MySQL extension `INDEX_LENGTH' `Index_length' MySQL extension `DATA_FREE' `Data_free' MySQL extension `AUTO_INCREMENT' `Auto_increment' MySQL extension `CREATE_TIME' `Create_time' MySQL extension `UPDATE_TIME' `Update_time' MySQL extension `CHECK_TIME' `Check_time' MySQL extension `TABLE_COLLATION' `Collation' MySQL extension `CHECKSUM' `Checksum' MySQL extension `CREATE_OPTIONS' `Create_options' MySQL extension `TABLE_COMMENT' `Comment' MySQL extension *Notes*: * `TABLE_SCHEMA' and `TABLE_NAME' are a single field in a *Note `SHOW': show. display, for example `Table_in_db1'. * `TABLE_TYPE' should be `BASE TABLE' or `VIEW'. Currently, the *Note `TABLES': tables-table. table does not list `TEMPORARY' tables. * For partitioned tables, beginning with MySQL 5.1.9, the `ENGINE' column shows the name of the storage engine used by all partitions. (Previously, this column showed `PARTITION' for such tables.) * The `TABLE_ROWS' column is `NULL' if the table is in the `INFORMATION_SCHEMA' database. For *Note `InnoDB': innodb-storage-engine. tables, the row count is only a rough estimate used in SQL optimization. (This is also true if the *Note `InnoDB': innodb-storage-engine. table is partitioned.) * Prior to MySQL 5.1.12, MySQL Cluster allocated storage for variable-width columns in 10-page extents of 32 kilobytes each; thus, the `DATA_LENGTH' for such columns was reported in increments of 320 KB. Beginning with MySQL 5.1.12, the `DATA_LENGTH' column reflects the true amount of storage for variable-width columns of *Note `NDB': mysql-cluster. tables. (Bug#18413) For *Note `NDB': mysql-cluster. tables, `DATA_LENGTH' includes data stored in main memory only; the `MAX_DATA_LENGTH' and `DATA_FREE' columns apply to Disk Data. * Beginning with MySQL Cluster NDB 7.0.22 and MySQL Cluster NDB 7.1.11, for MySQL Cluster Disk Data tables, `MAX_DATA_LENGTH' shows the space allocated for the disk part of a Disk Data table or fragment. (In-memory data resource usage is reported by the `DATA_LENGTH' column.) * Beginning with MySQL 5.1.28, the `DATA_FREE' column shows the free space in bytes for `InnoDB' tables. Beginning with MySQL Cluster NDB 7.0.22 and MySQL Cluster NDB 7.1.11, `DATA_FREE' shows the space allocated on disk for, but not used by, a Disk Data table or fragment on disk. (In-memory data resource usage is reported by the `DATA_LENGTH' column.) * We have nothing for the table's default character set. `TABLE_COLLATION' is close, because collation names begin with a character set name. * Beginning with MySQL 5.1.9, the `CREATE_OPTIONS' column shows `partitioned' if the table is partitioned. The following statements are equivalent: SELECT table_name FROM INFORMATION_SCHEMA.TABLES WHERE table_schema = 'DB_NAME' [AND table_name LIKE 'WILD'] SHOW TABLES FROM DB_NAME [LIKE 'WILD']  File: manual.info, Node: columns-table, Next: statistics-table, Prev: tables-table, Up: information-schema 20.3 The `INFORMATION_SCHEMA COLUMNS' Table =========================================== The *Note `COLUMNS': columns-table. table provides information about columns in tables. `INFORMATION_SCHEMA' Name *Note `SHOW': show. Remarks Name `TABLE_CATALOG' `NULL' `TABLE_SCHEMA' `TABLE_NAME' `COLUMN_NAME' `Field' `ORDINAL_POSITION' see notes `COLUMN_DEFAULT' `Default' `IS_NULLABLE' `Null' `DATA_TYPE' `Type' `CHARACTER_MAXIMUM_LENGTH' `Type' `CHARACTER_OCTET_LENGTH' `NUMERIC_PRECISION' `Type' `NUMERIC_SCALE' `Type' `CHARACTER_SET_NAME' `COLLATION_NAME' `Collation' `COLUMN_TYPE' `Type' MySQL extension `COLUMN_KEY' `Key' MySQL extension `EXTRA' `Extra' MySQL extension `PRIVILEGES' `Privileges' MySQL extension `COLUMN_COMMENT' `Comment' MySQL extension *Notes*: * In *Note `SHOW': show, the `Type' display includes values from several different *Note `COLUMNS': columns-table. columns. * `ORDINAL_POSITION' is necessary because you might want to say `ORDER BY ORDINAL_POSITION'. Unlike *Note `SHOW': show, *Note `SELECT': select. does not have automatic ordering. * `CHARACTER_OCTET_LENGTH' should be the same as `CHARACTER_MAXIMUM_LENGTH', except for multi-byte character sets. * `CHARACTER_SET_NAME' can be derived from `Collation'. For example, if you say `SHOW FULL COLUMNS FROM t', and you see in the `Collation' column a value of `latin1_swedish_ci', the character set is what is before the first underscore: `latin1'. The following statements are nearly equivalent: SELECT COLUMN_NAME, DATA_TYPE, IS_NULLABLE, COLUMN_DEFAULT FROM INFORMATION_SCHEMA.COLUMNS WHERE table_name = 'TBL_NAME' [AND table_schema = 'DB_NAME'] [AND column_name LIKE 'WILD'] SHOW COLUMNS FROM TBL_NAME [FROM DB_NAME] [LIKE 'WILD']  File: manual.info, Node: statistics-table, Next: user-privileges-table, Prev: columns-table, Up: information-schema 20.4 The `INFORMATION_SCHEMA STATISTICS' Table ============================================== The *Note `STATISTICS': statistics-table. table provides information about table indexes. `INFORMATION_SCHEMA' Name *Note `SHOW': show. Remarks Name `TABLE_CATALOG' `NULL' `TABLE_SCHEMA' = Database `TABLE_NAME' `Table' `NON_UNIQUE' `Non_unique' `INDEX_SCHEMA' = Database `INDEX_NAME' `Key_name' `SEQ_IN_INDEX' `Seq_in_index' `COLUMN_NAME' `Column_name' `COLLATION' `Collation' `CARDINALITY' `Cardinality' `SUB_PART' `Sub_part' MySQL extension `PACKED' `Packed' MySQL extension `NULLABLE' `Null' MySQL extension `INDEX_TYPE' `Index_type' MySQL extension `COMMENT' `Comment' MySQL extension *Notes*: * There is no standard table for indexes. The preceding list is similar to what SQL Server 2000 returns for `sp_statistics', except that we replaced the name `QUALIFIER' with `CATALOG' and we replaced the name `OWNER' with `SCHEMA'. Clearly, the preceding table and the output from *Note `SHOW INDEX': show-index. are derived from the same parent. So the correlation is already close. The following statements are equivalent: SELECT * FROM INFORMATION_SCHEMA.STATISTICS WHERE table_name = 'TBL_NAME' AND table_schema = 'DB_NAME' SHOW INDEX FROM TBL_NAME FROM DB_NAME  File: manual.info, Node: user-privileges-table, Next: schema-privileges-table, Prev: statistics-table, Up: information-schema 20.5 The `INFORMATION_SCHEMA USER_PRIVILEGES' Table =================================================== The *Note `USER_PRIVILEGES': user-privileges-table. table provides information about global privileges. This information comes from the `mysql.user' grant table. `INFORMATION_SCHEMA' Name *Note `SHOW': show. Remarks Name `GRANTEE' `'USER_NAME'@'HOST_NAME'' value, MySQL extension `TABLE_CATALOG' `NULL', MySQL extension `PRIVILEGE_TYPE' MySQL extension `IS_GRANTABLE' MySQL extension *Notes*: * This is a nonstandard table. It takes its values from the `mysql.user' table.  File: manual.info, Node: schema-privileges-table, Next: table-privileges-table, Prev: user-privileges-table, Up: information-schema 20.6 The `INFORMATION_SCHEMA SCHEMA_PRIVILEGES' Table ===================================================== The *Note `SCHEMA_PRIVILEGES': schema-privileges-table. table provides information about schema (database) privileges. This information comes from the `mysql.db' grant table. `INFORMATION_SCHEMA' Name *Note `SHOW': show. Remarks Name `GRANTEE' `'USER_NAME'@'HOST_NAME'' value, MySQL extension `TABLE_CATALOG' `NULL', MySQL extension `TABLE_SCHEMA' MySQL extension `PRIVILEGE_TYPE' MySQL extension `IS_GRANTABLE' MySQL extension *Notes*: * This is a nonstandard table. It takes its values from the `mysql.db' table.  File: manual.info, Node: table-privileges-table, Next: column-privileges-table, Prev: schema-privileges-table, Up: information-schema 20.7 The `INFORMATION_SCHEMA TABLE_PRIVILEGES' Table ==================================================== The *Note `TABLE_PRIVILEGES': table-privileges-table. table provides information about table privileges. This information comes from the `mysql.tables_priv' grant table. `INFORMATION_SCHEMA' Name *Note `SHOW': show. Remarks Name `GRANTEE' `'USER_NAME'@'HOST_NAME'' value `TABLE_CATALOG' `NULL' `TABLE_SCHEMA' `TABLE_NAME' `PRIVILEGE_TYPE' `IS_GRANTABLE' *Notes*: * `PRIVILEGE_TYPE' can contain one (and only one) of these values: `SELECT', `INSERT', `UPDATE', `REFERENCES', `ALTER', `INDEX', `DROP', `CREATE VIEW'. The following statements are _not_ equivalent: SELECT ... FROM INFORMATION_SCHEMA.TABLE_PRIVILEGES SHOW GRANTS ...  File: manual.info, Node: column-privileges-table, Next: character-sets-table, Prev: table-privileges-table, Up: information-schema 20.8 The `INFORMATION_SCHEMA COLUMN_PRIVILEGES' Table ===================================================== The *Note `COLUMN_PRIVILEGES': column-privileges-table. table provides information about column privileges. This information comes from the `mysql.columns_priv' grant table. `INFORMATION_SCHEMA' Name *Note `SHOW': show. Remarks Name `GRANTEE' `'USER_NAME'@'HOST_NAME'' value `TABLE_CATALOG' `NULL' `TABLE_SCHEMA' `TABLE_NAME' `COLUMN_NAME' `PRIVILEGE_TYPE' `IS_GRANTABLE' *Notes*: * In the output from *Note `SHOW FULL COLUMNS': show-columns, the privileges are all in one field and in lowercase, for example, `select,insert,update,references'. In *Note `COLUMN_PRIVILEGES': column-privileges-table, there is one privilege per row, in uppercase. * `PRIVILEGE_TYPE' can contain one (and only one) of these values: `SELECT', `INSERT', `UPDATE', `REFERENCES'. * If the user has `GRANT OPTION' privilege, `IS_GRANTABLE' should be `YES'. Otherwise, `IS_GRANTABLE' should be `NO'. The output does not list `GRANT OPTION' as a separate privilege. The following statements are _not_ equivalent: SELECT ... FROM INFORMATION_SCHEMA.COLUMN_PRIVILEGES SHOW GRANTS ...  File: manual.info, Node: character-sets-table, Next: collations-table, Prev: column-privileges-table, Up: information-schema 20.9 The `INFORMATION_SCHEMA CHARACTER_SETS' Table ================================================== The *Note `CHARACTER_SETS': character-sets-table. table provides information about available character sets. `INFORMATION_SCHEMA' Name *Note `SHOW': show. Remarks Name `CHARACTER_SET_NAME' `Charset' `DEFAULT_COLLATE_NAME' `Default collation' `DESCRIPTION' `Description' MySQL extension `MAXLEN' `Maxlen' MySQL extension The following statements are equivalent: SELECT * FROM INFORMATION_SCHEMA.CHARACTER_SETS [WHERE CHARACTER_SET_NAME LIKE 'WILD'] SHOW CHARACTER SET [LIKE 'WILD']  File: manual.info, Node: collations-table, Next: collation-character-set-applicability-table, Prev: character-sets-table, Up: information-schema 20.10 The `INFORMATION_SCHEMA COLLATIONS' Table =============================================== The *Note `COLLATIONS': collations-table. table provides information about collations for each character set. `INFORMATION_SCHEMA' Name *Note `SHOW': show. Remarks Name `COLLATION_NAME' `Collation' `CHARACTER_SET_NAME' `Charset' MySQL extension `ID' `Id' MySQL extension `IS_DEFAULT' `Default' MySQL extension `IS_COMPILED' `Compiled' MySQL extension `SORTLEN' `Sortlen' MySQL extension * `COLLATION_NAME' is the collation name. * `CHARACTER_SET_NAME' is the name of the character set with which the collation is associated. * `ID' is the collation ID. * `IS_DEFAULT' indicates whether the collation is the default for its character set. * `IS_COMPILED' indicates whether the character set is compiled into the server. * `SORTLEN' is related to the amount of memory required to sort strings expressed in the character set. Collation information is also available from the *Note `SHOW COLLATION': show-collation. statement. The following statements are equivalent: SELECT COLLATION_NAME FROM INFORMATION_SCHEMA.COLLATIONS [WHERE COLLATION_NAME LIKE 'WILD'] SHOW COLLATION [LIKE 'WILD']  File: manual.info, Node: collation-character-set-applicability-table, Next: table-constraints-table, Prev: collations-table, Up: information-schema 20.11 The `INFORMATION_SCHEMA COLLATION_CHARACTER_SET_APPLICABILITY' Table ========================================================================== The *Note `COLLATION_CHARACTER_SET_APPLICABILITY': collation-character-set-applicability-table. table indicates what character set is applicable for what collation. The columns are equivalent to the first two display fields that we get from *Note `SHOW COLLATION': show-collation. `INFORMATION_SCHEMA' Name *Note `SHOW': show. Remarks Name `COLLATION_NAME' `Collation' `CHARACTER_SET_NAME' `Charset'  File: manual.info, Node: table-constraints-table, Next: key-column-usage-table, Prev: collation-character-set-applicability-table, Up: information-schema 20.12 The `INFORMATION_SCHEMA TABLE_CONSTRAINTS' Table ====================================================== The *Note `TABLE_CONSTRAINTS': table-constraints-table. table describes which tables have constraints. `INFORMATION_SCHEMA' Name *Note `SHOW': show. Remarks Name `CONSTRAINT_CATALOG' `NULL' `CONSTRAINT_SCHEMA' `CONSTRAINT_NAME' `TABLE_SCHEMA' `TABLE_NAME' `CONSTRAINT_TYPE' *Notes*: * The `CONSTRAINT_TYPE' value can be `UNIQUE', `PRIMARY KEY', or `FOREIGN KEY'. * The `UNIQUE' and `PRIMARY KEY' information is about the same as what you get from the `Key_name' field in the output from *Note `SHOW INDEX': show-index. when the `Non_unique' field is `0'. * The `CONSTRAINT_TYPE' column can contain one of these values: `UNIQUE', `PRIMARY KEY', `FOREIGN KEY', `CHECK'. This is a *Note `CHAR': char. (not *Note `ENUM': enum.) column. The `CHECK' value is not available until we support `CHECK'.  File: manual.info, Node: key-column-usage-table, Next: routines-table, Prev: table-constraints-table, Up: information-schema 20.13 The `INFORMATION_SCHEMA KEY_COLUMN_USAGE' Table ===================================================== The *Note `KEY_COLUMN_USAGE': key-column-usage-table. table describes which key columns have constraints. `INFORMATION_SCHEMA' Name *Note `SHOW': show. Remarks Name `CONSTRAINT_CATALOG' `NULL' `CONSTRAINT_SCHEMA' `CONSTRAINT_NAME' `TABLE_CATALOG' `TABLE_SCHEMA' `TABLE_NAME' `COLUMN_NAME' `ORDINAL_POSITION' `POSITION_IN_UNIQUE_CONSTRAINT' `REFERENCED_TABLE_SCHEMA' `REFERENCED_TABLE_NAME' `REFERENCED_COLUMN_NAME' *Notes*: * If the constraint is a foreign key, then this is the column of the foreign key, not the column that the foreign key references. * The value of `ORDINAL_POSITION' is the column's position within the constraint, not the column's position within the table. Column positions are numbered beginning with 1. * The value of `POSITION_IN_UNIQUE_CONSTRAINT' is `NULL' for unique and primary-key constraints. For foreign-key constraints, it is the ordinal position in key of the table that is being referenced. Suppose that there are two tables name `t1' and `t3' that have the following definitions: CREATE TABLE t1 ( s1 INT, s2 INT, s3 INT, PRIMARY KEY(s3) ) ENGINE=InnoDB; CREATE TABLE t3 ( s1 INT, s2 INT, s3 INT, KEY(s1), CONSTRAINT CO FOREIGN KEY (s2) REFERENCES t1(s3) ) ENGINE=InnoDB; For those two tables, the *Note `KEY_COLUMN_USAGE': key-column-usage-table. table has two rows: * One row with `CONSTRAINT_NAME' = `'PRIMARY'', `TABLE_NAME' = `'t1'', `COLUMN_NAME' = `'s3'', `ORDINAL_POSITION' = `1', `POSITION_IN_UNIQUE_CONSTRAINT' = `NULL'. * One row with `CONSTRAINT_NAME' = `'CO'', `TABLE_NAME' = `'t3'', `COLUMN_NAME' = `'s2'', `ORDINAL_POSITION' = `1', `POSITION_IN_UNIQUE_CONSTRAINT' = `1'.  File: manual.info, Node: routines-table, Next: views-table, Prev: key-column-usage-table, Up: information-schema 20.14 The `INFORMATION_SCHEMA ROUTINES' Table ============================================= The *Note `ROUTINES': routines-table. table provides information about stored routines (both procedures and functions). The *Note `ROUTINES': routines-table. table does not include user-defined functions (UDFs) at this time. The column named ``mysql.proc' name' indicates the `mysql.proc' table column that corresponds to the *Note `INFORMATION_SCHEMA.ROUTINES': routines-table. table column, if any. `INFORMATION_SCHEMA' Name `mysql.proc' Name Remarks `SPECIFIC_NAME' `specific_name' `ROUTINE_CATALOG' `NULL' `ROUTINE_SCHEMA' `db' `ROUTINE_NAME' `name' `ROUTINE_TYPE' `type' `{PROCEDURE|FUNCTION}' `DTD_IDENTIFIER' data type descriptor `ROUTINE_BODY' `SQL' `ROUTINE_DEFINITION' `body' `EXTERNAL_NAME' `NULL' `EXTERNAL_LANGUAGE' `language' `NULL' `PARAMETER_STYLE' `SQL' `IS_DETERMINISTIC' `is_deterministic' `SQL_DATA_ACCESS' `sql_data_access' `SQL_PATH' `NULL' `SECURITY_TYPE' `security_type' `CREATED' `created' `LAST_ALTERED' `modified' `SQL_MODE' `sql_mode' MySQL extension `ROUTINE_COMMENT' `comment' MySQL extension `DEFINER' `definer' MySQL extension `CHARACTER_SET_CLIENT' MySQL extension `COLLATION_CONNECTION' MySQL extension `DATABASE_COLLATION' MySQL extension *Notes*: * MySQL calculates `EXTERNAL_LANGUAGE' thus: * If `mysql.proc.language='SQL'', `EXTERNAL_LANGUAGE' is `NULL' * Otherwise, `EXTERNAL_LANGUAGE' is what is in `mysql.proc.language'. However, we do not have external languages yet, so it is always `NULL'. * `CHARACTER_SET_CLIENT' is the session value of the `character_set_client' system variable when the routine was created. `COLLATION_CONNECTION' is the session value of the `collation_connection' system variable when the routine was created. `DATABASE_COLLATION' is the collation of the database with which the routine is associated. These columns were added in MySQL 5.1.21.  File: manual.info, Node: views-table, Next: triggers-table, Prev: routines-table, Up: information-schema 20.15 The `INFORMATION_SCHEMA VIEWS' Table ========================================== The *Note `VIEWS': views-table. table provides information about views in databases. You must have the `SHOW VIEW' privilege to access this table. `INFORMATION_SCHEMA' Name *Note `SHOW': show. Remarks Name `TABLE_CATALOG' `NULL' `TABLE_SCHEMA' `TABLE_NAME' `VIEW_DEFINITION' `CHECK_OPTION' `IS_UPDATABLE' `DEFINER' `SECURITY_TYPE' `CHARACTER_SET_CLIENT' MySQL extension `COLLATION_CONNECTION' MySQL extension *Notes*: * The `VIEW_DEFINITION' column has most of what you see in the `Create Table' field that *Note `SHOW CREATE VIEW': show-create-view. produces. Skip the words before *Note `SELECT': select. and skip the words `WITH CHECK OPTION'. Suppose that the original statement was: CREATE VIEW v AS SELECT s2,s1 FROM t WHERE s1 > 5 ORDER BY s1 WITH CHECK OPTION; Then the view definition looks like this: SELECT s2,s1 FROM t WHERE s1 > 5 ORDER BY s1 * The `CHECK_OPTION' column has a value of `NONE', `CASCADE', or `LOCAL'. * MySQL sets a flag, called the view updatability flag, at *Note `CREATE VIEW': create-view. time. The flag is set to `YES' (true) if *Note `UPDATE': update. and *Note `DELETE': delete. (and similar operations) are legal for the view. Otherwise, the flag is set to `NO' (false). The `IS_UPDATABLE' column in the *Note `VIEWS': views-table. table displays the status of this flag. It means that the server always knows whether a view is updatable. If the view is not updatable, statements such *Note `UPDATE': update, *Note `DELETE': delete, and *Note `INSERT': insert. are illegal and will be rejected. (Note that even if a view is updatable, it might not be possible to insert into it; for details, refer to *Note create-view::.) * The `DEFINER' column indicates who defined the view. `SECURITY_TYPE' has a value of `DEFINER' or `INVOKER'. * `CHARACTER_SET_CLIENT' is the session value of the `character_set_client' system variable when the view was created. `COLLATION_CONNECTION' is the session value of the `collation_connection' system variable when the view was created. These columns were added in MySQL 5.1.21. MySQL lets you use different `sql_mode' settings to tell the server the type of SQL syntax to support. For example, you might use the `ANSI' SQL mode to ensure MySQL correctly interprets the standard SQL concatenation operator, the double bar (`||'), in your queries. If you then create a view that concatenates items, you might worry that changing the `sql_mode' setting to a value different from `ANSI' could cause the view to become invalid. But this is not the case. No matter how you write out a view definition, MySQL always stores it the same way, in a canonical form. Here is an example that shows how the server changes a double bar concatenation operator to a `CONCAT()' function: mysql> SET sql_mode = 'ANSI'; Query OK, 0 rows affected (0.00 sec) mysql> CREATE VIEW test.v AS SELECT 'a' || 'b' as col1; Query OK, 0 rows affected (0.00 sec) mysql> SELECT VIEW_DEFINITION FROM INFORMATION_SCHEMA.VIEWS -> WHERE TABLE_SCHEMA = 'test' AND TABLE_NAME = 'v'; +----------------------------------+ | VIEW_DEFINITION | +----------------------------------+ | select concat('a','b') AS `col1` | +----------------------------------+ 1 row in set (0.00 sec) The advantage of storing a view definition in canonical form is that changes made later to the value of `sql_mode' will not affect the results from the view. However an additional consequence is that comments prior to *Note `SELECT': select. are stripped from the definition by the server.  File: manual.info, Node: triggers-table, Next: plugins-table, Prev: views-table, Up: information-schema 20.16 The `INFORMATION_SCHEMA TRIGGERS' Table ============================================= The *Note `TRIGGERS': triggers-table. table provides information about triggers. You must have the `TRIGGER' privilege to access this table (prior to MySQL 5.1.23, you must have the `SUPER' privilege). You can see results only for databases and tables for which you have the `TRIGGER' privilege, or (prior to MySQL 5.1.23) if you have the `SUPER' privilege). `INFORMATION_SCHEMA' Name *Note `SHOW': show. Remarks Name `TRIGGER_CATALOG' `NULL' `TRIGGER_SCHEMA' `TRIGGER_NAME' `Trigger' `EVENT_MANIPULATION' `Event' `EVENT_OBJECT_CATALOG' `NULL' `EVENT_OBJECT_SCHEMA' `EVENT_OBJECT_TABLE' `Table' `ACTION_ORDER' `0' `ACTION_CONDITION' `NULL' `ACTION_STATEMENT' `Statement' `ACTION_ORIENTATION' `ROW' `ACTION_TIMING' `Timing' `ACTION_REFERENCE_OLD_TABLE' `NULL' `ACTION_REFERENCE_NEW_TABLE' `NULL' `ACTION_REFERENCE_OLD_ROW' `OLD' `ACTION_REFERENCE_NEW_ROW' `NEW' `CREATED' `NULL' (`0') `SQL_MODE' MySQL extension `DEFINER' MySQL extension `CHARACTER_SET_CLIENT' MySQL extension `COLLATION_CONNECTION' MySQL extension `DATABASE_COLLATION' MySQL extension *Notes*: * The `TRIGGER_SCHEMA' and `TRIGGER_NAME' columns contain the name of the database in which the trigger occurs and the trigger name, respectively. * The `EVENT_MANIPULATION' column contains one of the values `'INSERT'', `'DELETE'', or `'UPDATE''. * As noted in *Note triggers::, every trigger is associated with exactly one table. The `EVENT_OBJECT_SCHEMA' and `EVENT_OBJECT_TABLE' columns contain the database in which this table occurs, and the table's name. * The `ACTION_ORDER' column contains the ordinal position of the trigger's action within the list of all similar triggers on the same table. Currently, this value is always `0', because it is not possible to have more than one trigger with the same `EVENT_MANIPULATION' and `ACTION_TIMING' on the same table. * The `ACTION_STATEMENT' column contains the statement to be executed when the trigger is invoked. This is the same as the text displayed in the `Statement' column of the output from *Note `SHOW TRIGGERS': show-triggers. Note that this text uses UTF-8 encoding. * The `ACTION_ORIENTATION' column always contains the value `'ROW''. * The `ACTION_TIMING' column contains one of the two values `'BEFORE'' or `'AFTER''. * The columns `ACTION_REFERENCE_OLD_ROW' and `ACTION_REFERENCE_NEW_ROW' contain the old and new column identifiers, respectively. This means that `ACTION_REFERENCE_OLD_ROW' always contains the value `'OLD'' and `ACTION_REFERENCE_NEW_ROW' always contains the value `'NEW''. * The `SQL_MODE' column shows the server SQL mode that was in effect at the time when the trigger was created (and thus which remains in effect for this trigger whenever it is invoked, _regardless of the current server SQL mode_). The possible range of values for this column is the same as that of the `sql_mode' system variable. See *Note server-sql-mode::. * The `DEFINER' column was added in MySQL 5.1.2. `DEFINER' indicates who defined the trigger. * `CHARACTER_SET_CLIENT' is the session value of the `character_set_client' system variable when the trigger was created. `COLLATION_CONNECTION' is the session value of the `collation_connection' system variable when the trigger was created. `DATABASE_COLLATION' is the collation of the database with which the trigger is associated. These columns were added in MySQL 5.1.21. * The following columns currently always contain `NULL': `TRIGGER_CATALOG', `EVENT_OBJECT_CATALOG', `ACTION_CONDITION', `ACTION_REFERENCE_OLD_TABLE', `ACTION_REFERENCE_NEW_TABLE', and `CREATED'. Example, using the `ins_sum' trigger defined in *Note triggers::: mysql> SELECT * FROM INFORMATION_SCHEMA.TRIGGERS\G *************************** 1. row *************************** TRIGGER_CATALOG: NULL TRIGGER_SCHEMA: test TRIGGER_NAME: ins_sum EVENT_MANIPULATION: INSERT EVENT_OBJECT_CATALOG: NULL EVENT_OBJECT_SCHEMA: test EVENT_OBJECT_TABLE: account ACTION_ORDER: 0 ACTION_CONDITION: NULL ACTION_STATEMENT: SET @sum = @sum + NEW.amount ACTION_ORIENTATION: ROW ACTION_TIMING: BEFORE ACTION_REFERENCE_OLD_TABLE: NULL ACTION_REFERENCE_NEW_TABLE: NULL ACTION_REFERENCE_OLD_ROW: OLD ACTION_REFERENCE_NEW_ROW: NEW CREATED: NULL SQL_MODE: DEFINER: me@localhost See also *Note show-triggers::.  File: manual.info, Node: plugins-table, Next: engines-table, Prev: triggers-table, Up: information-schema 20.17 The `INFORMATION_SCHEMA PLUGINS' Table ============================================ The *Note `PLUGINS': plugins-table. table provides information about server plugins. `INFORMATION_SCHEMA' Name *Note `SHOW': show. Remarks Name `PLUGIN_NAME' `Name' MySQL extension `PLUGIN_VERSION' MySQL extension `PLUGIN_STATUS' `Status' MySQL extension `PLUGIN_TYPE' `Type' MySQL extension `PLUGIN_TYPE_VERSION' MySQL extension `PLUGIN_LIBRARY' `Library' MySQL extension `PLUGIN_LIBRARY_VERSION' MySQL extension `PLUGIN_AUTHOR' MySQL extension `PLUGIN_DESCRIPTION' MySQL extension `PLUGIN_LICENSE' MySQL extension *Notes*: * The *Note `PLUGINS': plugins-table. table is a nonstandard table. It was added in MySQL 5.1.5. * `PLUGIN_NAME' is the name used to refer to the plugin in statements such as *Note `INSTALL PLUGIN': install-plugin. and *Note `UNINSTALL PLUGIN': uninstall-plugin. * `PLUGIN_VERSION' is the version from the plugin's general type descriptor. * `PLUGIN_STATUS' indicates the plugin status, one of `ACTIVE', `INACTIVE', `DISABLED', or `DELETED'. * `PLUGIN_TYPE' indicates the type of plugin, such as `STORAGE ENGINE' or `INFORMATION_SCHEMA'. * `PLUGIN_TYPE_VERSION' is the version from the plugin's type-specific descriptor. * `PLUGIN_LIBRARY' is the name of the plugin shared object file. This is the name used to refer to the plugin file in statements such as *Note `INSTALL PLUGIN': install-plugin. and *Note `UNINSTALL PLUGIN': uninstall-plugin. This file is located in the directory named by the `plugin_dir' system variable. If the library name is `NULL', the plugin is compiled in and cannot be uninstalled with *Note `UNINSTALL PLUGIN': uninstall-plugin. * `PLUGIN_LIBRARY_VERSION' indicates the plugin API interface version. * `PLUGIN_AUTHOR' names the plugin author. * `PLUGIN_DESCRIPTION' provides a short description of the plugin. * `PLUGIN_LICENSE' indicates how the plugin is licensed; for example, `GPL'. This column was added in MySQL 5.1.12. For plugins installed with *Note `INSTALL PLUGIN': install-plugin, the `PLUGIN_NAME' and `PLUGIN_LIBRARY' values are also registered in the `mysql.plugin' table. These statements are equivalent: SELECT PLUGIN_NAME, PLUGIN_STATUS, PLUGIN_TYPE, PLUGIN_LIBRARY, PLUGIN_LICENSE FROM INFORMATION_SCHEMA.PLUGINS; SHOW PLUGINS; For information about plugin data structures that form the basis of the information in the *Note `PLUGINS': plugins-table. table, see *Note plugin-api::. Plugin information is also available using the *Note `SHOW PLUGINS': show-plugins. statement. See *Note show-plugins::.  File: manual.info, Node: engines-table, Next: partitions-table, Prev: plugins-table, Up: information-schema 20.18 The `INFORMATION_SCHEMA ENGINES' Table ============================================ The *Note `PLUGINS': plugins-table. table provides information about storage engines. `INFORMATION_SCHEMA' Name *Note `SHOW': show. Remarks Name `ENGINE' `Engine' MySQL extension `SUPPORT' `Support' MySQL extension `COMMENT' `Comment' MySQL extension `TRANSACTIONS' `Transactions' MySQL extension `XA' `XA' MySQL extension `SAVEPOINTS' `Savepoints' MySQL extension *Notes*: * The *Note `ENGINES': engines-table. table is a nonstandard table. It was added in MySQL 5.1.5. See also *Note show-engines::.  File: manual.info, Node: partitions-table, Next: events-table, Prev: engines-table, Up: information-schema 20.19 The `INFORMATION_SCHEMA PARTITIONS' Table =============================================== The *Note `PARTITIONS': partitions-table. table provides information about table partitions. See *Note partitioning::, for more information about partitioning tables. `INFORMATION_SCHEMA' Name *Note `SHOW': show. Remarks Name `TABLE_CATALOG' MySQL extension `TABLE_SCHEMA' MySQL extension `TABLE_NAME' MySQL extension `PARTITION_NAME' MySQL extension `SUBPARTITION_NAME' MySQL extension `PARTITION_ORDINAL_POSITION' MySQL extension `SUBPARTITION_ORDINAL_POSITION' MySQL extension `PARTITION_METHOD' MySQL extension `SUBPARTITION_METHOD' MySQL extension `PARTITION_EXPRESSION' MySQL extension `SUBPARTITION_EXPRESSION' MySQL extension `PARTITION_DESCRIPTION' MySQL extension `TABLE_ROWS' MySQL extension `AVG_ROW_LENGTH' MySQL extension `DATA_LENGTH' MySQL extension `MAX_DATA_LENGTH' MySQL extension `INDEX_LENGTH' MySQL extension `DATA_FREE' MySQL extension `CREATE_TIME' MySQL extension `UPDATE_TIME' MySQL extension `CHECK_TIME' MySQL extension `CHECKSUM' MySQL extension `PARTITION_COMMENT' MySQL extension `NODEGROUP' MySQL extension `TABLESPACE_NAME' MySQL extension *Notes*: * The *Note `PARTITIONS': partitions-table. table is a nonstandard table. It was added in MySQL 5.1.6. Each record in this table corresponds to an individual partition or subpartition of a partitioned table. * `TABLE_CATALOG': This column is always `NULL'. * `TABLE_SCHEMA': This column contains the name of the database to which the table belongs. * `TABLE_NAME': This column contains the name of the table containing the partition. * `PARTITION_NAME': The name of the partition. * `SUBPARTITION_NAME': If the *Note `PARTITIONS': partitions-table. table record represents a subpartition, then this column contains the name of subpartition; otherwise it is `NULL'. * `PARTITION_ORDINAL_POSITION': All partitions are indexed in the same order as they are defined, with `1' being the number assigned to the first partition. The indexing can change as partitions are added, dropped, and reorganized; the number shown is this column reflects the current order, taking into account any indexing changes. * `SUBPARTITION_ORDINAL_POSITION': Subpartitions within a given partition are also indexed and reindexed in the same manner as partitions are indexed within a table. * `PARTITION_METHOD': One of the values `RANGE', `LIST', `HASH', `LINEAR HASH', `KEY', or `LINEAR KEY'; that is, one of the available partitioning types as discussed in *Note partitioning-types::. * `SUBPARTITION_METHOD': One of the values `HASH', `LINEAR HASH', `KEY', or `LINEAR KEY'; that is, one of the available subpartitioning types as discussed in *Note partitioning-subpartitions::. * `PARTITION_EXPRESSION': This is the expression for the partitioning function used in the *Note `CREATE TABLE': create-table. or *Note `ALTER TABLE': alter-table. statement that created the table's current partitioning scheme. For example, consider a partitioned table created in the `test' database using this statement: CREATE TABLE tp ( c1 INT, c2 INT, c3 VARCHAR(25) ) PARTITION BY HASH(c1 + c2) PARTITIONS 4; The `PARTITION_EXPRESSION' column in a PARTITIONS table record for a partition from this table displays `c1 + c2', as shown here: mysql> SELECT DISTINCT PARTITION_EXPRESSION > FROM INFORMATION_SCHEMA.PARTITIONS > WHERE TABLE_NAME='tp' AND TABLE_SCHEMA='test'; +----------------------+ | PARTITION_EXPRESSION | +----------------------+ | c1 + c2 | +----------------------+ 1 row in set (0.09 sec) * `SUBPARTITION_EXPRESSION': This works in the same fashion for the subpartitioning expression that defines the subpartitioning for a table as `PARTITION_EXPRESSION' does for the partitioning expression used to define a table's partitioning. If the table has no subpartitions, then this column is `NULL'. * `PARTITION_DESCRIPTION': This column is used for RANGE and LIST partitions. For a `RANGE' partition, it contains the value set in the partition's `VALUES LESS THAN' clause, which can be either an integer or `MAXVALUE'. For a `LIST' partition, this column contains the values defined in the partition's `VALUES IN' clause, which is a comma-separated list of integer values. For partitions whose `PARTITION_METHOD' is other than `RANGE' or `LIST', this column is always `NULL'. * `TABLE_ROWS': The number of table rows in the partition. For partitioned *Note `InnoDB': innodb-storage-engine. tables, the row count given in the `TABLE_ROWS' column is only an estimated value used in SQL optimization, and may not always be exact. Beginning with MySQL Cluster NDB 7.0.22 and MySQL Cluster NDB 7.1.11, `TABLE_ROWS' shows correct information for *Note `NDB': mysql-cluster. tables. Previously, for partitions of *Note `NDB': mysql-cluster. tables, the `TABLE_ROWS' column value was always 0. For *Note `NDB': mysql-cluster. tables, you can also obtain this information using the *Note `ndb_desc': mysql-cluster-programs-ndb-desc. utility. * `AVG_ROW_LENGTH': The average length of the rows stored in this partition or subpartition, in bytes. This is the same as `DATA_LENGTH' divided by `TABLE_ROWS'. Beginning with MySQL Cluster NDB 7.0.22 and MySQL Cluster NDB 7.1.11, `AVG_ROW_LENGTH' includes statistics for partitions of *Note `NDB': mysql-cluster. tables, whether the tables use implicit or explicit partitioning. (Previously the value of this column was always 0 for partitions of *Note `NDB': mysql-cluster. tables.) You can also obtain equivalent information using the *Note `ndb_desc': mysql-cluster-programs-ndb-desc. utility. * `DATA_LENGTH': The total length of all rows stored in this partition or subpartition, in bytes--that is, the total number of bytes stored in the partition or subpartition. Beginning with MySQL Cluster NDB 7.0.22 and MySQL Cluster NDB 7.1.11, `DATA_LENGTH' shows correct information for in-memory data in *Note `NDB': mysql-cluster. tables. Previously, for partitions of *Note `NDB': mysql-cluster. tables, the `DATA_LENGTH' column value was always 0. For *Note `NDB': mysql-cluster. tables, you can also obtain this information using the *Note `ndb_desc': mysql-cluster-programs-ndb-desc. utility. * `MAX_DATA_LENGTH': The maximum number of bytes that can be stored in this partition or subpartition. Beginning with MySQL Cluster NDB 7.0.22 and MySQL Cluster NDB 7.1.11, `MAX_DATA_LENGTH' shows the space allocated for the disk part of a MySQL Cluster Disk Data table or fragment. (Previously, for partitions of *Note `NDB': mysql-cluster. tables, the `MAX_DATA_LENGTH' column value was always `NULL'.) For *Note `NDB': mysql-cluster. tables, you can also obtain this information using the *Note `ndb_desc': mysql-cluster-programs-ndb-desc. utility. * `INDEX_LENGTH': The length of the index file for this partition or subpartition, in bytes. For partitions of *Note `NDB': mysql-cluster. tables, whether the tables use implicit or explicit partitioning, the `INDEX_LENGTH' column value is always 0. However, you can obtain equivalent information using the *Note `ndb_desc': mysql-cluster-programs-ndb-desc. utility. * `DATA_FREE': The number of bytes allocated to the partition or subpartition but not used. For MySQL Cluster Disk Data tables, beginning with MySQL Cluster NDB 7.0.22 and MySQL Cluster NDB 7.1.11, `DATA_FREE' shows the space allocated on disk for, but not used by, a Disk Data table or fragment on disk. (Previously, for partitions of *Note `NDB': mysql-cluster. tables, the value of this column was always 0.) For *Note `NDB': mysql-cluster. tables, you can also obtain this information using the *Note `ndb_desc': mysql-cluster-programs-ndb-desc. utility. * `CREATE_TIME': The time of the partition's or subpartition's creation. * `UPDATE_TIME': The time that the partition or subpartition was last modified. * `CHECK_TIME': The last time that the table to which this partition or subpartition belongs was checked. *Note*: Some storage engines do not update this time; for tables using these storage engines, this value is always `NULL'. * `CHECKSUM': The checksum value, if any; otherwise, this column is `NULL'. * `PARTITION_COMMENT': This column contains the text of any comment made for the partition. The default value for this column is an empty string. * `NODEGROUP': This is the nodegroup to which the partition belongs. This is relevant only to MySQL Cluster tables; otherwise the value of this column is always `0'. * `TABLESPACE_NAME': This column contains the name of the tablespace to which the partition belongs. Currently, the value of this column is always `DEFAULT'. * *Important*: If any partitioned tables created in a MySQL version prior to MySQL 5.1.6 are present following an upgrade to MySQL 5.1.6 or later, it is not possible to *Note `SELECT': select. from, *Note `SHOW': show, or *Note `DESCRIBE': describe. the *Note `PARTITIONS': partitions-table. table. See *Note news-5-1-6:: _before_ upgrading from MySQL 5.1.5 or earlier to MySQL 5.1.6 or later. * A nonpartitioned table has one record in *Note `INFORMATION_SCHEMA.PARTITIONS': partitions-table.; however, the values of the `PARTITION_NAME', `SUBPARTITION_NAME', `PARTITION_ORDINAL_POSITION', `SUBPARTITION_ORDINAL_POSITION', `PARTITION_METHOD', `SUBPARTITION_METHOD', `PARTITION_EXPRESSION', `SUBPARTITION_EXPRESSION', and `PARTITION_DESCRIPTION' columns are all `NULL'. (The `PARTITION_COMMENT' column in this case is blank.) In MySQL 5.1, there is also only one record in the *Note `PARTITIONS': partitions-table. table for a table using the *Note `NDBCLUSTER': mysql-cluster. storage engine. The same columns are also `NULL' (or empty) as for a nonpartitioned table.  File: manual.info, Node: events-table, Next: files-table, Prev: partitions-table, Up: information-schema 20.20 The `INFORMATION_SCHEMA EVENTS' Table =========================================== The *Note `EVENTS': events-table. table provides information about scheduled events, which are discussed in *Note events::. The `SHOW Name' values correspond to column names of the *Note `SHOW EVENTS': show-events. statement. `INFORMATION_SCHEMA' Name *Note `SHOW': show. Remarks Name `EVENT_CATALOG' `NULL', MySQL extension `EVENT_SCHEMA' `Db' MySQL extension `EVENT_NAME' `Name' MySQL extension `DEFINER' `Definer' MySQL extension `TIME_ZONE' `Time zone' MySQL extension `EVENT_BODY' MySQL extension `EVENT_DEFINITION' MySQL extension `EVENT_TYPE' `Type' MySQL extension `EXECUTE_AT' `Execute at' MySQL extension `INTERVAL_VALUE' `Interval value' MySQL extension `INTERVAL_FIELD' `Interval field' MySQL extension `SQL_MODE' MySQL extension `STARTS' `Starts' MySQL extension `ENDS' `Ends' MySQL extension `STATUS' `Status' MySQL extension `ON_COMPLETION' MySQL extension `CREATED' MySQL extension `LAST_ALTERED' MySQL extension `LAST_EXECUTED' MySQL extension `EVENT_COMMENT' MySQL extension `ORIGINATOR' `Originator' MySQL extension `CHARACTER_SET_CLIENT' `character_set_client' MySQL extension `COLLATION_CONNECTION' `collation_connection' MySQL extension `DATABASE_COLLATION' `Database Collation' MySQL extension *Notes*: * The *Note `EVENTS': events-table. table is a nonstandard table. It was added in MySQL 5.1.6. * `EVENT_CATALOG': The value of this column is always `NULL'. * `EVENT_SCHEMA': The name of the schema (database) to which this event belongs. * `EVENT_NAME': The name of the event. * `DEFINER': The account of the user who created the event, in `'USER_NAME'@'HOST_NAME'' format. * `TIME_ZONE': The event time zone, which is the time zone used for scheduling the event and that is in effect within the event as it executes. The default value is `SYSTEM'. This column was added in MySQL 5.1.17. See *Note news-5-1-17::, for important information if you are using the Event Scheduler and are upgrading to MySQL 5.1.17 or later from an earlier version. * `EVENT_BODY': The language used for the statements in the event's *Note `DO': do. clause; in MySQL 5.1, this is always `SQL'. This column was added in MySQL 5.1.12. It is not to be confused with the column of the same name (now named `EVENT_DEFINITION') that existed in earlier MySQL versions. * `EVENT_DEFINITION': The text of the SQL statement making up the event's *Note `DO': do. clause; in other words, the statement executed by this event. *Note*: Prior to MySQL 5.1.12, this column was named `EVENT_BODY'. * `EVENT_TYPE': The event repetition type, either `ONE TIME' (transient) or `RECURRING' (repeating). * `EXECUTE_AT': For a one-time event, this is the *Note `DATETIME': datetime. value specified in the `AT' clause of the *Note `CREATE EVENT': create-event. statement used to create the event, or of the last *Note `ALTER EVENT': alter-event. statement that modified the event. The value shown in this column reflects the addition or subtraction of any `INTERVAL' value included in the event's `AT' clause. For example, if an event is created using `ON SCHEDULE AT CURRENT_TIMESTAMP + '1:6' DAY_HOUR', and the event was created at 2006-02-09 14:05:30, the value shown in this column would be `'2006-02-10 20:05:30''. If the event's timing is determined by an `EVERY' clause instead of an `AT' clause (that is, if the event is recurring), the value of this column is `NULL'. * `INTERVAL_VALUE': For recurring events, this column contains the numeric portion of the event's `EVERY' clause. For a one-time event (that is, an event whose timing is determined by an `AT' clause), this column is `NULL'. * `INTERVAL_FIELD': For recurring events, this column contains the units portion of the `EVERY' clause governing the timing of the event. Thus, this column contains a value such as '*Note `YEAR': year.', '`QUARTER'', '`DAY'', and so on. *Note*: In early MySQL 5.1 releases, this value was prefixed with '`INTERVAL_'', and was displayed as '`INTERVAL_YEAR'', '`INTERVAL_QUARTER'', '`INTERVAL_DAY'', and so on. For a one-time event (that is, an event whose timing is determined by an `AT' clause), this column is `NULL'. * `SQL_MODE': The SQL mode in effect at the time the event was created or altered. * `STARTS': For a recurring event whose definition includes a `STARTS' clause, this column contains the corresponding *Note `DATETIME': datetime. value. As with the `EXECUTE_AT' column, this value resolves any expressions used. If there is no `STARTS' clause affecting the timing of the event, this column is `NULL'. (Prior to MySQL 5.1.8, it contained `0000-00-00 00:00:00' in such cases.) * `ENDS': For a recurring event whose definition includes a `ENDS' clause, this column contains the corresponding *Note `DATETIME': datetime. value. As with the `EXECUTE_AT' column, this value resolves any expressions used. If there is no `ENDS' clause affecting the timing of the event, this column is `NULL'. * `STATUS': One of the three values `ENABLED', `DISABLED', or `SLAVESIDE_DISABLED'. `SLAVESIDE_DISABLED' was added to the list of possible values for this column in MySQL 5.1.18. This value indicates that the creation of the event occurred on another MySQL server acting as a replication master and was replicated to the current MySQL server which is acting as a slave, but the event is not presently being executed on the slave. See *Note replication-features-invoked::, for more information. * `ON_COMPLETION': One of the two values `PRESERVE' or `NOT PRESERVE'. * `CREATED': The date and time when the event was created. This is a *Note `DATETIME': datetime. value. * `LAST_ALTERED': The date and time when the event was last modified. This is a *Note `DATETIME': datetime. value. If the event has not been modified since its creation, this column holds the same value as the `CREATED' column. * `LAST_EXECUTED': The date and time when the event last executed. A *Note `DATETIME': datetime. value. If the event has never executed, this column is `NULL'. Before MySQL 5.1.23, `LAST_EXECUTED' indicates when event finished executing. As of 5.1.23, `LAST_EXECUTED' instead indicates when the event started. As a result, the `ENDS' column is never less than `LAST_EXECUTED'. * `EVENT_COMMENT': The text of a comment, if the event has one. If not, the value of this column is an empty string. * `ORIGINATOR': The server ID of the MySQL server on which the event was created; used in replication. The default value is 0. This column was added in MySQL 5.1.18. * `CHARACTER_SET_CLIENT' is the session value of the `character_set_client' system variable when the event was created. `COLLATION_CONNECTION' is the session value of the `collation_connection' system variable when the event was created. `DATABASE_COLLATION' is the collation of the database with which the event is associated. These columns were added in MySQL 5.1.21. *Example*: Suppose that the user `jon@ghidora' creates an event named `e_daily', and then modifies it a few minutes later using an *Note `ALTER EVENT': alter-event. statement, as shown here: DELIMITER | CREATE EVENT e_daily ON SCHEDULE EVERY 1 DAY COMMENT 'Saves total number of sessions then clears the table each day' DO BEGIN INSERT INTO site_activity.totals (time, total) SELECT CURRENT_TIMESTAMP, COUNT(*) FROM site_activity.sessions; DELETE FROM site_activity.sessions; END | DELIMITER ; ALTER EVENT e_daily ENABLED; (Note that comments can span multiple lines.) This user can then run the following *Note `SELECT': select. statement, and obtain the output shown: mysql> SELECT * FROM INFORMATION_SCHEMA.EVENTS > WHERE EVENT_NAME = 'e_daily' > AND EVENT_SCHEMA = 'myschema'\G *************************** 1. row *************************** EVENT_CATALOG: NULL EVENT_SCHEMA: test EVENT_NAME: e_daily DEFINER: paul@localhost TIME_ZONE: SYSTEM EVENT_BODY: SQL EVENT_DEFINITION: BEGIN INSERT INTO site_activity.totals (time, total) SELECT CURRENT_TIMESTAMP, COUNT(*) FROM site_activity.sessions; DELETE FROM site_activity.sessions; END EVENT_TYPE: RECURRING EXECUTE_AT: NULL INTERVAL_VALUE: 1 INTERVAL_FIELD: DAY SQL_MODE: STARTS: 2008-09-03 12:13:39 ENDS: NULL STATUS: ENABLED ON_COMPLETION: NOT PRESERVE CREATED: 2008-09-03 12:13:39 LAST_ALTERED: 2008-09-03 12:13:39 LAST_EXECUTED: NULL EVENT_COMMENT: Saves total number of sessions then clears the table each day ORIGINATOR: 1 CHARACTER_SET_CLIENT: latin1 COLLATION_CONNECTION: latin1_swedish_ci DATABASE_COLLATION: latin1_swedish_ci Times in the *Note `EVENTS': events-table. table are displayed using the event time zone or the current session time zone. Prior to MySQL 5.1.17, some of the times are displayed in UTC rather than the event time zone. For details, see *Note events-metadata::. See also *Note show-events::.  File: manual.info, Node: files-table, Next: processlist-table, Prev: events-table, Up: information-schema 20.21 The `INFORMATION_SCHEMA FILES' Table ========================================== The *Note `FILES': files-table. table provides information about the files in which MySQL *Note `NDB': mysql-cluster. Disk Data tables are stored. *Note*: This table provides information about Disk Data _files_ only; you cannot use it for determining disk space allocation or availability for individual `NDB' tables. However, beginning with MySQL Cluster NDB 6.3.27 and MySQL Cluster NDB 7.0.8, it is possible to see how much space is allocated for each *Note `NDB': mysql-cluster. table having data stored on disk, as well as how much remains available for storage of of data on disk for that table, using *Note `ndb_desc': mysql-cluster-programs-ndb-desc. For more information, see *Note mysql-cluster-programs-ndb-desc::. `INFORMATION_SCHEMA' Name *Note `SHOW': show. Remarks Name `FILE_ID' MySQL extension `FILE_NAME' MySQL extension `FILE_TYPE' MySQL extension `TABLESPACE_NAME' MySQL extension `TABLE_CATALOG' MySQL extension `TABLE_SCHEMA' MySQL extension `TABLE_NAME' MySQL extension `LOGFILE_GROUP_NAME' MySQL extension `LOGFILE_GROUP_NUMBER' MySQL extension `ENGINE' MySQL extension `FULLTEXT_KEYS' MySQL extension `DELETED_ROWS' MySQL extension `UPDATE_COUNT' MySQL extension `FREE_EXTENTS' MySQL extension `TOTAL_EXTENTS' MySQL extension `EXTENT_SIZE' MySQL extension `INITIAL_SIZE' MySQL extension `MAXIMUM_SIZE' MySQL extension `AUTOEXTEND_SIZE' MySQL extension `CREATION_TIME' MySQL extension `LAST_UPDATE_TIME' MySQL extension `LAST_ACCESS_TIME' MySQL extension `RECOVER_TIME' MySQL extension `TRANSACTION_COUNTER' MySQL extension `VERSION' MySQL extension `ROW_FORMAT' MySQL extension `TABLE_ROWS' MySQL extension `AVG_ROW_LENGTH' MySQL extension `DATA_LENGTH' MySQL extension `MAX_DATA_LENGTH' MySQL extension `INDEX_LENGTH' MySQL extension `DATA_FREE' MySQL extension `CREATE_TIME' MySQL extension `UPDATE_TIME' MySQL extension `CHECK_TIME' MySQL extension `CHECKSUM' MySQL extension `STATUS' MySQL extension `EXTRA' MySQL extension *Notes*: * `FILE_ID' column values are auto-generated. * `FILE_NAME' is the name of an `UNDO' log file created by *Note `CREATE LOGFILE GROUP': create-logfile-group. or *Note `ALTER LOGFILE GROUP': alter-logfile-group, or of a data file created by *Note `CREATE TABLESPACE': create-tablespace. or *Note `ALTER TABLESPACE': alter-tablespace. * `FILE_TYPE' is one of the values `UNDOFILE' or `DATAFILE'. Beginning with MySQL Cluster NDB 6.2.19, MySQL Cluster NDB 6.3.32, MySQL Cluster NDB 7.0.13, and MySQL Cluster NDB 7.1.2, this column can also have the value `TABLESPACE'. * `TABLESPACE_NAME' is the name of the tablespace with which the file is associated. * Currently, the value of the `TABLESPACE_CATALOG' column is always `NULL'. * `TABLE_NAME' is the name of the Disk Data table with which the file is associated, if any. * The `LOGFILE_GROUP_NAME' column gives the name of the log file group to which the log file or data file belongs. * For an `UNDO' log file, the `LOGFILE_GROUP_NUMBER' contains the auto-generated ID number of the log file group to which the log file belongs. * For a MySQL Cluster Disk Data log file or data file, the value of the `ENGINE' column is always *Note `NDB': mysql-cluster. or *Note `NDBCLUSTER': mysql-cluster. * For a MySQL Cluster Disk Data log file or data file, the value of the `FULLTEXT_KEYS' column is always empty. * The `FREE EXTENTS' column displays the number of extents which have not yet been used by the file. The `TOTAL EXTENTS' column show the total number of extents allocated to the file. The difference between these two columns is the number of extents currently in use by the file: SELECT TOTAL_EXTENTS - FREE_EXTENTS AS extents_used FROM INFORMATION_SCHEMA.FILES WHERE FILE_NAME = 'myfile.dat'; You can approximate the amount of disk space in use by the file by multiplying this difference by the value of the `EXTENT_SIZE' column, which gives the size of an extent for the file in bytes: SELECT (TOTAL_EXTENTS - FREE_EXTENTS) * EXTENT_SIZE AS bytes_used FROM INFORMATION_SCHEMA.FILES WHERE FILE_NAME = 'myfile.dat'; Similarly, you can estimate the amount of space that remains available in a given file by multiplying `FREE_EXTENTS' by `EXTENT_SIZE': SELECT FREE_EXTENTS * EXTENT_SIZE AS bytes_free FROM INFORMATION_SCHEMA.FILES WHERE FILE_NAME = 'myfile.dat'; *Important*: The byte values produced by the preceding queries are approximations only, and their precision is inversely proportional to the value of `EXTENT_SIZE'. That is, the larger `EXTENT_SIZE' becomes, the less accurate the approximations are. It is also important to remember that once an extent is used, it cannot be freed again without dropping the data file of which it is a part. This means that deletes from a Disk Data table do _not_ release disk space. The extent size can be set in a *Note `CREATE TABLESPACE': create-tablespace. statement. See *Note create-tablespace::, for more information. * The `INITIAL_SIZE' column shows the size in bytes of the file. This is the same value that was used in the `INITIAL_SIZE' clause of the *Note `CREATE LOGFILE GROUP': create-logfile-group, *Note `ALTER LOGFILE GROUP': alter-logfile-group, *Note `CREATE TABLESPACE': create-tablespace, or *Note `ALTER TABLESPACE': alter-tablespace. statement used to create the file. For MySQL Cluster Disk Data files, the value of the `MAXIMUM_SIZE' column is always the same as `INITIAL_SIZE', and the `AUTOEXTEND_SIZE' column is always empty. * The `CREATION_TIME' column shows the date and time when the file was created. The `LAST_UPDATE_TIME' column displays the date and time when the file was last modified. The `LAST_ACCESSED' column provides the date and time when the file was last accessed by the server. Currently, the values of these columns are as reported by the operating system, and are not supplied by the *Note `NDB': mysql-cluster. storage engine. Where no value is provided by the operating system, these columns display `0000-00-00 00:00:00'. * For MySQL Cluster Disk Data files, the value of the `RECOVER_TIME' and `TRANSACTION_COUNTER' columns is always `0'. * For MySQL Cluster Disk Data files, the following columns are always `NULL': * `VERSION' * `ROW_FORMAT' * `TABLE_ROWS' * `AVG_ROW_LENGTH' * `DATA_LENGTH' * `MAX_DATA_LENGTH' * `INDEX_LENGTH' * `DATA_FREE' * `CREATE_TIME' * `UPDATE_TIME' * `CHECK_TIME' * `CHECKSUM' * For MySQL Cluster Disk Data files, the value of the `STATUS' column is always `NORMAL'. * For MySQL Cluster Disk Data files, the `EXTRA' column shows which data node the file belongs to, as each data node has its own copy of the file. Suppose that you use this statement on a MySQL Cluster with four data nodes: CREATE LOGFILE GROUP mygroup ADD UNDOFILE 'new_undo.dat' INITIAL_SIZE 2G ENGINE NDB; After running the *Note `CREATE LOGFILE GROUP': create-logfile-group. statement successfully, you should see a result similar to the one shown here for this query against the *Note `FILES': files-table. table: mysql> SELECT LOGFILE_GROUP_NAME, FILE_TYPE, EXTRA -> FROM INFORMATION_SCHEMA.FILES -> WHERE FILE_NAME = 'new_undo.dat'; +--------------------+-------------+----------------+ | LOGFILE_GROUP_NAME | FILE_TYPE | EXTRA | +--------------------+-------------+----------------+ | mygroup | UNDO FILE | CLUSTER_NODE=3 | | mygroup | UNDO FILE | CLUSTER_NODE=4 | | mygroup | UNDO FILE | CLUSTER_NODE=5 | | mygroup | UNDO FILE | CLUSTER_NODE=6 | +--------------------+-------------+----------------+ 4 rows in set (0.01 sec) * The *Note `FILES': files-table. table is a nonstandard table. It was added in MySQL 5.1.6. * Beginning with MySQL 5.1.14, an additional row is present in the *Note `FILES': files-table. table following the creation of a logfile group. This row has `NULL' for the value of the `FILE_NAME' column. For this row, the value of the `FILE_ID' column is always `0', that of the `FILE_TYPE' column is always `UNDO FILE', and that of the `STATUS' column is always `NORMAL'. Currently, the value of the `ENGINE' column is always *Note `NDBCLUSTER': mysql-cluster. The `FREE_EXTENTS' column in this row shows the total number of free extents available to all undo files belonging to a given log file group whose name and number are shown in the `LOGFILE_GROUP_NAME' and `LOGFILE_GROUP_NUMBER' columns, respectively. Suppose there are no existing log file groups on your MySQL Cluster, and you create one using the following statement: mysql> CREATE LOGFILE GROUP lg1 -> ADD UNDOFILE 'undofile.dat' -> INITIAL_SIZE = 16M -> UNDO_BUFFER_SIZE = 1M -> ENGINE = NDB; Query OK, 0 rows affected (3.81 sec) You can now see this `NULL' row when you query the *Note `FILES': files-table. table: mysql> SELECT DISTINCT -> FILE_NAME AS File, -> FREE_EXTENTS AS Free, -> TOTAL_EXTENTS AS Total, -> EXTENT_SIZE AS Size, -> INITIAL_SIZE AS Initial -> FROM INFORMATION_SCHEMA.FILES; +--------------+---------+---------+------+----------+ | File | Free | Total | Size | Initial | +--------------+---------+---------+------+----------+ | undofile.dat | NULL | 4194304 | 4 | 16777216 | | NULL | 4184068 | NULL | 4 | NULL | +--------------+---------+---------+------+----------+ 2 rows in set (0.01 sec) The total number of free extents available for undo logging is always somewhat less than the sum of the `TOTAL_EXTENTS' column values for all undo files in the log file group due to overhead required for maintaining the undo files. This can be seen by adding a second undo file to the log file group, then repeating the previous query against the *Note `FILES': files-table. table: mysql> ALTER LOGFILE GROUP lg1 -> ADD UNDOFILE 'undofile02.dat' -> INITIAL_SIZE = 4M -> ENGINE = NDB; Query OK, 0 rows affected (1.02 sec) mysql> SELECT DISTINCT -> FILE_NAME AS File, -> FREE_EXTENTS AS Free, -> TOTAL_EXTENTS AS Total, -> EXTENT_SIZE AS Size, -> INITIAL_SIZE AS Initial -> FROM INFORMATION_SCHEMA.FILES; +----------------+---------+---------+------+----------+ | File | Free | Total | Size | Initial | +----------------+---------+---------+------+----------+ | undofile.dat | NULL | 4194304 | 4 | 16777216 | | undofile02.dat | NULL | 1048576 | 4 | 4194304 | | NULL | 5223944 | NULL | 4 | NULL | +----------------+---------+---------+------+----------+ 3 rows in set (0.01 sec) The amount of free space in bytes which is available for undo logging by Disk Data tables using this log file group can be approximated by multiplying the number of free extents by the initial size: mysql> SELECT -> FREE_EXTENTS AS 'Free Extents', -> FREE_EXTENTS * EXTENT_SIZE AS 'Free Bytes' -> FROM INFORMATION_SCHEMA.FILES -> WHERE LOGFILE_GROUP_NAME = 'lg1' -> AND FILE_NAME IS NULL; +--------------+------------+ | Free Extents | Free Bytes | +--------------+------------+ | 5223944 | 20895776 | +--------------+------------+ 1 row in set (0.02 sec) If you create a MySQL Cluster Disk Data table and then insert some rows into it, you can see approximately how much space remains for undo logging afterward, for example: mysql> CREATE TABLESPACE ts1 -> ADD DATAFILE 'data1.dat' -> USE LOGFILE GROUP lg1 -> INITIAL_SIZE 512M -> ENGINE = NDB; Query OK, 0 rows affected (8.71 sec) mysql> CREATE TABLE dd ( -> c1 INT NOT NULL PRIMARY KEY, -> c2 INT, -> c3 DATE -> ) -> TABLESPACE ts1 STORAGE DISK -> ENGINE = NDB; Query OK, 0 rows affected (2.11 sec) mysql> INSERT INTO dd VALUES -> (NULL, 1234567890, '2007-02-02'), -> (NULL, 1126789005, '2007-02-03'), -> (NULL, 1357924680, '2007-02-04'), -> (NULL, 1642097531, '2007-02-05'); Query OK, 4 rows affected (0.01 sec) mysql> SELECT -> FREE_EXTENTS AS 'Free Extents', -> FREE_EXTENTS * EXTENT_SIZE AS 'Free Bytes' -> FROM INFORMATION_SCHEMA.FILES -> WHERE LOGFILE_GROUP_NAME = 'lg1' -> AND FILE_NAME IS NULL; +--------------+------------+ | Free Extents | Free Bytes | +--------------+------------+ | 5207565 | 20830260 | +--------------+------------+ 1 row in set (0.01 sec) * Beginning with MySQL Cluster NDB 6.2.19, MySQL Cluster NDB 6.3.32, MySQL Cluster NDB 7.0.13, and MySQL Cluster NDB 7.1.2, an additional row is present in the *Note `FILES': files-table. table for any tablespace, whether or not any data files are associated with the tablespace. This row has `NULL' for the value of the `FILE_NAME' column. For this row, the value of the `FILE_ID' column is always `0', that of the `FILE_TYPE' column is always `TABLESPACE', and that of the `STATUS' column is always `NORMAL'. Currently, the value of the `ENGINE' column is always *Note `NDBCLUSTER': mysql-cluster. * There are no *Note `SHOW': show. statements associated with the *Note `FILES': files-table. table. * For additional information, and examples of creating and dropping MySQL Cluster Disk Data objects, see *Note mysql-cluster-disk-data::.  File: manual.info, Node: processlist-table, Next: referential-constraints-table, Prev: files-table, Up: information-schema 20.22 The `INFORMATION_SCHEMA PROCESSLIST' Table ================================================ The *Note `PROCESSLIST': processlist-table. table provides information about which threads are running. `INFORMATION_SCHEMA' Name *Note `SHOW': show. Remarks Name `ID' `Id' MySQL extension `USER' `User' MySQL extension `HOST' `Host' MySQL extension `DB' `db' MySQL extension `COMMAND' `Command' MySQL extension *Note `TIME': time. `Time' MySQL extension `STATE' `State' MySQL extension `INFO' `Info' MySQL extension For an extensive description of the table columns, see *Note show-processlist::. *Notes*: * The *Note `PROCESSLIST': processlist-table. table is a nonstandard table. It was added in MySQL 5.1.7. * Like the output from the corresponding *Note `SHOW': show. statement, the *Note `PROCESSLIST': processlist-table. table will only show information about your own threads, unless you have the `PROCESS' privilege, in which case you will see information about other threads, too. As an anonymous user, you cannot see any rows at all. * If an SQL statement refers to *Note `INFORMATION_SCHEMA.PROCESSLIST': processlist-table, then MySQL will populate the entire table once, when statement execution begins, so there is read consistency during the statement. There is no read consistency for a multi-statement transaction, though. The following statements are equivalent: SELECT * FROM INFORMATION_SCHEMA.PROCESSLIST SHOW FULL PROCESSLIST  File: manual.info, Node: referential-constraints-table, Next: status-table, Prev: processlist-table, Up: information-schema 20.23 The `INFORMATION_SCHEMA REFERENTIAL_CONSTRAINTS' Table ============================================================ The *Note `REFERENTIAL_CONSTRAINTS': referential-constraints-table. table provides information about foreign keys. `INFORMATION_SCHEMA' Name *Note `SHOW': show. Remarks Name CONSTRAINT_CATALOG NULL CONSTRAINT_SCHEMA CONSTRAINT_NAME UNIQUE_CONSTRAINT_CATALOG NULL UNIQUE_CONSTRAINT_SCHEMA UNIQUE_CONSTRAINT_NAME MATCH_OPTION UPDATE_RULE DELETE_RULE TABLE_NAME REFERENCED_TABLE_NAME *Notes*: * The *Note `REFERENTIAL_CONSTRAINTS': referential-constraints-table. table was added in MySQL 5.1.10. The `REFERENCED_TABLE_NAME' column was added in MySQL 5.1.16. * `TABLE_NAME' has the same value as `TABLE_NAME' in *Note `INFORMATION_SCHEMA.TABLE_CONSTRAINTS': table-constraints-table. * `CONSTRAINT_SCHEMA' and `CONSTRAINT_NAME' identify the foreign key. * `UNIQUE_CONSTRAINT_SCHEMA', `UNIQUE_CONSTRAINT_NAME', and `REFERENCED_TABLE_NAME' identify the referenced key. (Note: Before MySQL 5.1.16, `UNIQUE_CONSTRAINT_NAME' incorrectly named the referenced table, not the constraint.) * The only valid value at this time for `MATCH_OPTION' is `NONE'. * The possible values for `UPDATE_RULE' or `DELETE_RULE' are `CASCADE', `SET NULL', `SET DEFAULT', `RESTRICT', `NO ACTION'.  File: manual.info, Node: status-table, Next: variables-table, Prev: referential-constraints-table, Up: information-schema 20.24 The `INFORMATION_SCHEMA GLOBAL_STATUS' and `SESSION_STATUS' Tables ======================================================================== The *Note `GLOBAL_STATUS': status-table. and *Note `SESSION_STATUS': status-table. tables provide information about server status variables. Their contents correspond to the information produced by the *Note `SHOW GLOBAL STATUS': show-status. and *Note `SHOW SESSION STATUS': show-status. statements (see *Note show-status::). `INFORMATION_SCHEMA' Name *Note `SHOW': show. Remarks Name VARIABLE_NAME Variable_name VARIABLE_VALUE Value *Notes*: * The *Note `GLOBAL_STATUS': status-table. and *Note `SESSION_STATUS': status-table. tables were added in MySQL 5.1.12. * Beginning with MySQL 5.1.19, the `VARIABLE_VALUE' column for each of these tables is defined as `VARCHAR(20480)'. Previously, this column had the data type `DECIMAL(22,7)', but was changed to avoid loss of data when working with status variables whose values were strings (Bug#26994).  File: manual.info, Node: variables-table, Next: profiling-table, Prev: status-table, Up: information-schema 20.25 The `INFORMATION_SCHEMA GLOBAL_VARIABLES' and `SESSION_VARIABLES' Tables ============================================================================== The *Note `GLOBAL_VARIABLES': variables-table. and *Note `SESSION_VARIABLES': variables-table. tables provide information about server status variables. Their contents correspond to the information produced by the *Note `SHOW GLOBAL VARIABLES': show-variables. and *Note `SHOW SESSION VARIABLES': show-variables. statements (see *Note show-variables::). `INFORMATION_SCHEMA' Name *Note `SHOW': show. Remarks Name VARIABLE_NAME Variable_name VARIABLE_VALUE Value *Notes*: * The *Note `GLOBAL_VARIABLES': variables-table. and *Note `SESSION_VARIABLES': variables-table. tables were added in MySQL 5.1.12. * Beginning with MySQL 5.1.19, the `VARIABLE_VALUE' column for each of these tables is defined as `VARCHAR(20480)'. Previously, this column had the data type *Note `LONGTEXT': blob.; this was changed to make these tables consistent with the *Note `GLOBAL_STATUS': status-table. and *Note `SESSION_STATUS': status-table. tables, whose definitions had been changed in that version (see *Note status-table::).  File: manual.info, Node: profiling-table, Next: other-information-schema-tables, Prev: variables-table, Up: information-schema 20.26 The `INFORMATION_SCHEMA PROFILING' Table ============================================== The *Note `PROFILING': profiling-table. table provides statement profiling information. Its contents correspond to the information produced by the *Note `SHOW PROFILES': show-profiles. and *Note `SHOW PROFILE': show-profile. statements (see *Note show-profiles::). The table is empty unless the `profiling' session variable is set to 1. `INFORMATION_SCHEMA' Name *Note `SHOW': show. Remarks Name `QUERY_ID' `Query_ID' `SEQ' `' `STATE' `Status' `DURATION' `Duration' `CPU_USER' `CPU_user' `CPU_SYSTEM' `CPU_system' `CONTEXT_VOLUNTARY' `Context_voluntary' `CONTEXT_INVOLUNTARY' `Context_involuntary' `BLOCK_OPS_IN' `Block_ops_in' `BLOCK_OPS_OUT' `Block_ops_out' `MESSAGES_SENT' `Messages_sent' `MESSAGES_RECEIVED' `Messages_received' `PAGE_FAULTS_MAJOR' `Page_faults_major' `PAGE_FAULTS_MINOR' `Page_faults_minor' `SWAPS' `Swaps' `SOURCE_FUNCTION' `Source_function' `SOURCE_FILE' `Source_file' `SOURCE_LINE' `Source_line' *Notes*: * The *Note `PROFILING': profiling-table. table was added in MySQL 5.1.24 but contains no information unless the *Note `SHOW PROFILE': show-profile. feature is enabled. The *Note `SHOW PROFILE': show-profile. feature is not included in binary distributions by default until MySQL 5.1.28. * `QUERY_ID' is a numeric statement identifier. * `SEQ' is a sequence number indicating the display order for rows with the same `QUERY_ID' value. * `STATE' is the profiling state to which the row measurements apply. * `DURATION' indicates how long statement execution remained in the given state, in seconds. * `CPU_USER' and `CPU_SYSTEM' indicate user and system CPU use, in seconds. * `CONTEXT_VOLUNTARY' and `CONTEXT_INVOLUNTARY' indicate how many voluntary and involuntary context switches occurred. * `BLOCK_OPS_IN' and `BLOCK_OPS_OUT' indicate the number of block input and output operations. * `MESSAGES_SENT' and `MESSAGES_RECEIVED' indicate the number of communication messages sent and received. * `PAGE_FAULTS_MAJOR' and `PAGE_FAULTS_MINOR' indicate the number of major and minor page faults. * `SWAPS' indicates how many swaps occurred. * `SOURCE_FUNCTION', `SOURCE_FILE', and `SOURCE_LINE' provide information indicating where in the source code the profiled state executes.  File: manual.info, Node: other-information-schema-tables, Next: extended-show, Prev: profiling-table, Up: information-schema 20.27 Other `INFORMATION_SCHEMA' Tables ======================================= We intend to implement additional `INFORMATION_SCHEMA' tables. In particular, we acknowledge the need for the `PARAMETERS' table. (`PARAMETERS' is implemented in MySQL 5.5.)  File: manual.info, Node: extended-show, Prev: other-information-schema-tables, Up: information-schema 20.28 Extensions to `SHOW' Statements ===================================== Some extensions to *Note `SHOW': show. statements accompany the implementation of `INFORMATION_SCHEMA': * *Note `SHOW': show. can be used to get information about the structure of `INFORMATION_SCHEMA' itself. * Several *Note `SHOW': show. statements accept a `WHERE' clause that provides more flexibility in specifying which rows to display. `INFORMATION_SCHEMA' is an information database, so its name is included in the output from *Note `SHOW DATABASES': show-databases. Similarly, *Note `SHOW TABLES': show-tables. can be used with `INFORMATION_SCHEMA' to obtain a list of its tables: mysql> SHOW TABLES FROM INFORMATION_SCHEMA; +---------------------------------------+ | Tables_in_INFORMATION_SCHEMA | +---------------------------------------+ | CHARACTER_SETS | | COLLATIONS | | COLLATION_CHARACTER_SET_APPLICABILITY | | COLUMNS | | COLUMN_PRIVILEGES | | ENGINES | | EVENTS | | FILES | | GLOBAL_STATUS | | GLOBAL_VARIABLES | | KEY_COLUMN_USAGE | | PARTITIONS | | PLUGINS | | PROCESSLIST | | REFERENTIAL_CONSTRAINTS | | ROUTINES | | SCHEMATA | | SCHEMA_PRIVILEGES | | SESSION_STATUS | | SESSION_VARIABLES | | STATISTICS | | TABLES | | TABLE_CONSTRAINTS | | TABLE_PRIVILEGES | | TRIGGERS | | USER_PRIVILEGES | | VIEWS | +---------------------------------------+ 27 rows in set (0.00 sec) *Note `SHOW COLUMNS': show-columns. and *Note `DESCRIBE': describe. can display information about the columns in individual `INFORMATION_SCHEMA' tables. *Note `SHOW': show. statements that accept a `LIKE' clause to limit the rows displayed also permit a `WHERE' clause that specifies more general conditions that selected rows must satisfy: SHOW CHARACTER SET SHOW COLLATION SHOW COLUMNS SHOW DATABASES SHOW FUNCTION STATUS SHOW INDEX SHOW OPEN TABLES SHOW PROCEDURE STATUS SHOW STATUS SHOW TABLE STATUS SHOW TABLES SHOW TRIGGERS SHOW VARIABLES The `WHERE' clause, if present, is evaluated against the column names displayed by the *Note `SHOW': show. statement. For example, the *Note `SHOW CHARACTER SET': show-character-set. statement produces these output columns: mysql> SHOW CHARACTER SET; +----------+-----------------------------+---------------------+--------+ | Charset | Description | Default collation | Maxlen | +----------+-----------------------------+---------------------+--------+ | big5 | Big5 Traditional Chinese | big5_chinese_ci | 2 | | dec8 | DEC West European | dec8_swedish_ci | 1 | | cp850 | DOS West European | cp850_general_ci | 1 | | hp8 | HP West European | hp8_english_ci | 1 | | koi8r | KOI8-R Relcom Russian | koi8r_general_ci | 1 | | latin1 | cp1252 West European | latin1_swedish_ci | 1 | | latin2 | ISO 8859-2 Central European | latin2_general_ci | 1 | ... To use a `WHERE' clause with *Note `SHOW CHARACTER SET': show-character-set, you would refer to those column names. As an example, the following statement displays information about character sets for which the default collation contains the string `'japanese'': mysql> SHOW CHARACTER SET WHERE `Default collation` LIKE '%japanese%'; +---------+---------------------------+---------------------+--------+ | Charset | Description | Default collation | Maxlen | +---------+---------------------------+---------------------+--------+ | ujis | EUC-JP Japanese | ujis_japanese_ci | 3 | | sjis | Shift-JIS Japanese | sjis_japanese_ci | 2 | | cp932 | SJIS for Windows Japanese | cp932_japanese_ci | 2 | | eucjpms | UJIS for Windows Japanese | eucjpms_japanese_ci | 3 | +---------+---------------------------+---------------------+--------+ This statement displays the multi-byte character sets: mysql> SHOW CHARACTER SET WHERE Maxlen > 1; +---------+---------------------------+---------------------+--------+ | Charset | Description | Default collation | Maxlen | +---------+---------------------------+---------------------+--------+ | big5 | Big5 Traditional Chinese | big5_chinese_ci | 2 | | ujis | EUC-JP Japanese | ujis_japanese_ci | 3 | | sjis | Shift-JIS Japanese | sjis_japanese_ci | 2 | | euckr | EUC-KR Korean | euckr_korean_ci | 2 | | gb2312 | GB2312 Simplified Chinese | gb2312_chinese_ci | 2 | | gbk | GBK Simplified Chinese | gbk_chinese_ci | 2 | | utf8 | UTF-8 Unicode | utf8_general_ci | 3 | | ucs2 | UCS-2 Unicode | ucs2_general_ci | 2 | | cp932 | SJIS for Windows Japanese | cp932_japanese_ci | 2 | | eucjpms | UJIS for Windows Japanese | eucjpms_japanese_ci | 3 | +---------+---------------------------+---------------------+--------+  File: manual.info, Node: connectors-apis, Next: extending-mysql, Prev: information-schema, Up: Top 21 Connectors and APIs ********************** * Menu: * connector-odbc:: MySQL Connector/ODBC * connector-net:: MySQL Connector/NET * connector-j:: MySQL Connector/J * connector-mxj:: MySQL Connector/MXJ * connector-cpp:: MySQL Connector/C++ * connector-c:: MySQL Connector/C * connector-ooo:: MySQL Connector/OpenOffice.org * libmysqld:: libmysqld, the Embedded MySQL Server Library * c:: MySQL C API * apis-php:: MySQL PHP API * apis-perl:: MySQL Perl API * apis-python:: MySQL Python API * apis-ruby:: MySQL Ruby APIs * apis-tcl:: MySQL Tcl API * apis-eiffel:: MySQL Eiffel Wrapper MySQL Connectors provide connectivity to the MySQL server for client programs. APIs provide low-level access to the MySQL protocol and MySQL resources. Both Connectors and the APIs enable you to connect and execute MySQL statements from another language or environment, including Java (JDBC), ODBC, Perl, Python, PHP, Ruby, and native C and embedded MySQL instances. *Note*: Connector version numbers do not correlate with MySQL Server version numbers. See also *Note connectors-apis-versions::. A number of connectors are developed by MySQL: * Connector/ODBC provides driver support for connecting to a MySQL server using the Open Database Connectivity (ODBC) API. Support is available for ODBC connectivity from Windows, Unix and Mac OS X platforms. * Connector/NET enables developers to create .NET applications that use data stored in a MySQL database. Connector/NET implement a fully functional ADO.NET interface and provides support for use with ADO.NET aware tools. Applications that want to use Connector/NET can be written in any of the supported .NET languages. The MySQL Visual Studio Plugin works with Connector/NET and Visual Studio 2005. The plugin is a MySQL DDEX Provider, which means that you can use the schema and data manipulation tools within Visual Studio to create and edit objects within a MySQL database. * Connector/J provides driver support for connecting to MySQL from a Java application using the standard Java Database Connectivity (JDBC) API. * Connector/MXJ is a tool that enables easy deployment and management of MySQL server and database through your Java application. * Connector/C++ is a tool that enables easy deployment and management of MySQL server and database through your C++ application. * Connector/C is a standalone replacement for the MySQL Client Library (`libmysql'). * Connector/OpenOffice.org is a tool that enables OpenOffice.org applications to connect to MySQL server. There are two direct access methods for using MySQL natively within a C application: * The C API provides low-level access to the MySQL protocol through the `libmysql' client library; this is the primary method used to connect to an instance of the MySQL server, and is used both by MySQL command line clients and many of the APIs also detailed in this section. MySQL Connector/C can now also be used for this purpose. * `libmysqld' is an embedded MySQL server library that enables you to embed an instance of the MySQL server into your C applications. If you need to access MySQL from a C application, or build an interface to MySQL for a language not supported by the Connectors or APIs in this chapter, the C API is where you would start. A number of programmers utilities are available to help with the process, and also covered in this section. The remaining APIs provide an interface to MySQL from specific application languages. These solutions are not developed or supported by MySQL. Basic information on their usage and abilities is provided here for reference purposes only. All the language APIs are developed using one of two methods, using `libmysql' or by building a _native driver_. The two solutions offer different benefits: * Using _`libmysql'_ offers complete compatibility with MySQL as it uses the same libraries as the MySQL client applications. However, the feature set is limited to the implementation and interfaces exposed through `libmysql' and the performance may be lower as data is copied between the native language, and the MySQL API components. MySQL Connector/C is a possible alternative to using `libmysql'. * _Native drivers_ are an implementation of the MySQL network protocol entirely within the host language or environment. Native drivers are fast, as there is less copying of data between components, and they can offer advanced functionality not available through the standard MySQL API. Native drivers are also easier to build and deploy, as you do not need a copy of the MySQL client libraries to build the native driver components. A list of many of the libraries and interfaces available for MySQL are shown in the table. See *Note connectors-apis-summary::. *MySQL APIs and Interfaces* EnvironmentAPI Type Notes Ada MySQL Bindings for GNU `libmysql' See MySQL Bindings for GNU Ada Ada (http://gnade.sourceforge.net/) C Connector/C Replacement See *Note connector-c::. for `libmysql' C++ Connector/C++ `libmysql' See *Note connector-cpp::. MySQL++ `libmysql' See MySQL++ Web site (http://tangentsoft.net/mysql++/doc/). MySQL wrapped `libmysql' See MySQL wrapped (http://www.alhem.net/project/mysql/). Cocoa MySQL-Cocoa `libmysql' Compatible with the Objective-C Cocoa environment. See `http://mysql-cocoa.sourceforge.net/' D MySQL for D `libmysql' See MySQL for D (http://www.steinmole.de/d/). Eiffel Eiffel MySQL `libmysql' See *Note apis-eiffel::. Erlang `erlang-mysql-driver' `libmysql' See `erlang-mysql-driver'. (http://code.google.com/p/erlang-mysql-driver/) Haskell Haskell MySQL Bindings Native See Brian O'Sullivan's pure Driver Haskell MySQL bindings (http://www.serpentine.com/software/mysql). `hsql-mysql' `libmysql' See MySQL driver for Haskell (http://hackage.haskell.org/cgi-bin/hackage-scripts/package/hsql-mysql-1.7). Java/JDBCConnector/J Native See *Note connector-j::. Driver Kaya MyDB `libmysql' See MyDB (http://kayalang.org/library/latest/MyDB). Lua LuaSQL `libmysql' See LuaSQL (http://www.keplerproject.org/luasql/). .NET/MonoConnector/NET Native See *Note connector-net::. Driver ObjectiveMySQL Bindings for `libmysql' See MySQL Bindings for Caml OBjective Caml Objective Caml (http://raevnos.pennmush.org/code/ocaml-mysql/). Octave Database bindings for `libmysql' See Database bindings for GNU Octave GNU Octave (http://octave.sourceforge.net/database/index.html). ODBC Connector/ODBC `libmysql' See *Note connector-odbc::. OpenOfficeMySQL `libmysql' Direct connectivity, without Connector/OpenOffice.org using JDBC/ODBC. See *Note connector-ooo::. Perl `DBI'/`DBD::mysql' `libmysql' See *Note apis-perl::. `Net::MySQL' Native See `Net::MySQL' Driver (http://search.cpan.org/dist/Net-MySQL/MySQL.pm) at CPAN PHP `mysql', `ext/mysql' `libmysql' See See section interface (deprecated) "apis-php-mysql" in the online manual. `mysqli', `ext/mysqli' `libmysql' See See section interface "apis-php-mysqli" in the online manual. `PDO_MYSQL' `libmysql' See See section "apis-php-ref.pdo-mysql" in the online manual. PDO mysqlnd Native See PHP PDO `mysqlnd'. Driver (http://forge.mysql.com/wiki/PHP_PDO_MYSQLND) Python MySQLdb `libmysql' See *Note apis-python::. Ruby MySQL/Ruby `libmysql' Uses `libmysql'. See *Note apis-ruby-mysqlruby::. Ruby/MySQL Native See *Note Driver apis-ruby-rubymysql::. Scheme `Myscsh' `libmysql' See `Myscsh' (http://www-pu.informatik.uni-tuebingen.de/users/knauel/myscsh/). SPL `sql_mysql' `libmysql' See `sql_mysql' for SPL (http://www.clifford.at/spl/spldoc/sql_mysql.html). Tcl MySQLtcl `libmysql' See *Note apis-tcl::. *MySQL Connector Versions and MySQL Server Versions* Connector Connector version MySQL Server version Connector/C++ 1.0.5 GA 5.1, 5.4, 5.5, 5.6 Connector/OpenOffice.org 1.0 GA 5.0, 5.1, 5.4, 5.5, 5.6 Connector/J 5.1.8 4.1, 5.0, 5.1, 5.4, 5.5, 5.6 Connector/NET 1.0 (No longer 4.0, 5.0 supported) Connector/NET 5.2 5.0, 5.1, 5.4, 5.5, 5.6 Connector/NET 6.0 5.0, 5.1, 5.4, 5.5, 5.6 Connector/NET 6.1 5.0, 5.1, 5.4, 5.5, 5.6 Connector/ODBC 3.51 (Unicode not 4.1, 5.0, 5.1, supported) 5.4, 5.5, 5.6 Connector/ODBC 5.1 4.1.1+, 5.0, 5.1, 5.4, 5.5, 5.6  File: manual.info, Node: connector-odbc, Next: connector-net, Prev: connectors-apis, Up: connectors-apis 21.1 MySQL Connector/ODBC ========================= * Menu: * connector-odbc-versions:: Connector/ODBC Versions * connector-odbc-introduction:: Connector/ODBC Introduction * connector-odbc-installation:: Connector/ODBC Installation * connector-odbc-configuration:: Connector/ODBC Configuration * connector-odbc-examples:: Connector/ODBC Examples * connector-odbc-reference:: Connector/ODBC Reference * connector-odbc-usagenotes:: Connector/ODBC Notes and Tips * connector-odbc-support:: Connector/ODBC Support The MySQL Connector/ODBC is the name for the family of MySQL ODBC drivers (previously called MyODBC drivers) that provide access to a MySQL database using the industry standard Open Database Connectivity (ODBC) API. This reference covers Connector/ODBC 3.51 and Connector/ODBC 5.1. Both releases provide an ODBC compliant interface to MySQL Server. MySQL Connector/ODBC provides both driver-manager based and native interfaces to the MySQL database, which full support for MySQL functionality, including stored procedures, transactions and, with Connector/ODBC 5.1, full Unicode compliance. For more information on the ODBC API standard and how to use it, refer to `http://support.microsoft.com/kb/110093'. The application development part of this reference assumes a good working knowledge of C, general DBMS knowledge, and finally, but not least, familiarity with MySQL. For more information about MySQL functionality and its syntax, refer to `http://dev.mysql.com/doc/'. Typically, you need to install Connector/ODBC only on Windows machines. For Unix and Mac OS X you can use the native MySQL network or named pipe to communicate with your MySQL database. You may need Connector/ODBC for Unix or Mac OS X if you have an application that requires an ODBC interface to communicate with the database. Applications that require ODBC to communicate with MySQL include ColdFusion, Microsoft Office, and Filemaker Pro. *Key topics:* * For help installing Connector/ODBC see *Note connector-odbc-installation::. * For information on the configuration options, see *Note connector-odbc-configuration-connection-parameters::. * For more information on connecting to a MySQL database from a Windows host using Connector/ODBC see *Note connector-odbc-examples-walkthrough::. * If you want to use Microsoft Access as an interface to a MySQL database using Connector/ODBC see *Note connector-odbc-examples-tools-with-access::. * General tips on using Connector/ODBC, including obtaining the last auto-increment ID see *Note connector-odbc-usagenotes-functionality::. * For tips and common questions on using Connector/ODBC with specific application see *Note connector-odbc-usagenotes-apptips::. * For a general list of Frequently Asked Questions see *Note connector-odbc-errors::. * Additional support when using Connector/ODBC is available, see *Note connector-odbc-support::.  File: manual.info, Node: connector-odbc-versions, Next: connector-odbc-introduction, Prev: connector-odbc, Up: connector-odbc 21.1.1 Connector/ODBC Versions ------------------------------ There are currently two version of Connector/ODBC available: * Connector/ODBC 5.1, currently in GA status, is a partial rewrite of the of the 3.51 code base and is designed to work with all versions of MySQL from 4.1.1. It does not work with versions of MySQL Server prior to 4.1.1. Connector/ODBC 5.1 also includes the following changes and improvements over the 3.51 release: * Improved support on Windows 64-bit platforms. * Full Unicode support at the driver level. This includes support for the `SQL_WCHAR' data type, and support for Unicode login, password and DSN configurations. For more information,. see Microsoft Knowledgebase Article #716246 (http://msdn2.microsoft.com/en-us/library/ms716246.aspx). * Support for the `SQL_NUMERIC_STRUCT' data type, which provides easier access to the precise definition of numeric values. For more information, see Microsoft Knowledgebase Article #714556 (http://msdn2.microsoft.com/en-us/library/ms714556.aspx) * Native Windows setup library. This replaces the Qt library based interface for configuring DSN information within the ODBC Data Sources application. * Support for the ODBC descriptor, which improves the handling and metadata of columns and parameter data. For more information, see Microsoft Knowledgebase Article #716339 (http://msdn2.microsoft.com/en-us/library/ms716339.aspx). * Connector/ODBC 3.51 is the current release of the 32-bit ODBC driver, also known as the MySQL ODBC 3.51 driver. Connector/ODBC 3.51 has support for ODBC 3.5x specification level 1 (complete core API + level 2 features) to continue to provide all functionality of ODBC for accessing MySQL. The manual for versions of Connector/ODBC older than 3.51 can be located in the corresponding binary or source distribution. Please note that versions of Connector/ODBC earlier than the 3.51 revision were not fully compliant with the ODBC specification. *Note*: From this section onward, the primary focus of this guide is the Connector/ODBC 3.51 and Connector/ODBC 5.1 drivers. *Note*: Version numbers for MySQL products are formatted as X.X.X. However, Windows tools (Control Panel, properties display) may show the version numbers as XX.XX.XX. For example, the official MySQL formatted version number 5.0.9 may be displayed by Windows tools as 5.00.09. The two versions are the same; only the number display format is different.  File: manual.info, Node: connector-odbc-introduction, Next: connector-odbc-installation, Prev: connector-odbc-versions, Up: connector-odbc 21.1.2 Connector/ODBC Introduction ---------------------------------- * Menu: * connector-odbc-general-information:: General Information About ODBC and Connector/ODBC ODBC (Open Database Connectivity) provides a way for client programs to access a wide range of databases or data sources. ODBC is a standardized API that enables connections to SQL database servers. It was developed according to the specifications of the SQL Access Group and defines a set of function calls, error codes, and data types that can be used to develop database-independent applications. ODBC usually is used when database independence or simultaneous access to different data sources is required. For more information about ODBC, refer to `http://support.microsoft.com/kb/110093'.  File: manual.info, Node: connector-odbc-general-information, Prev: connector-odbc-introduction, Up: connector-odbc-introduction 21.1.2.1 General Information About ODBC and Connector/ODBC .......................................................... * Menu: * connector-odbc-architecture:: Connector/ODBC Architecture * connector-odbc-driver-manager:: ODBC Driver Managers Open Database Connectivity (ODBC) is a widely accepted application-programming interface (API) for database access. It is based on the Call-Level Interface (CLI) specifications from X/Open and ISO/IEC for database APIs and uses Structured Query Language (SQL) as its database access language. A survey of ODBC functions supported by Connector/ODBC is given at *Note connector-odbc-reference-api::. For general information about ODBC, see `http://support.microsoft.com/kb/110093'.  File: manual.info, Node: connector-odbc-architecture, Next: connector-odbc-driver-manager, Prev: connector-odbc-general-information, Up: connector-odbc-general-information 21.1.2.2 Connector/ODBC Architecture .................................... The Connector/ODBC architecture is based on five components, as shown in the following diagram: Connector/ODBC Architecture * *Application:* The Application uses the ODBC API to access the data from the MySQL server. The ODBC API in turn uses the communicates with the Driver Manager. The Application communicates with the Driver Manager using the standard ODBC calls. The Application does not care where the data is stored, how it is stored, or even how the system is configured to access the data. It needs to know only the Data Source Name (DSN). A number of tasks are common to all applications, no matter how they use ODBC. These tasks are: * Selecting the MySQL server and connecting to it * Submitting SQL statements for execution * Retrieving results (if any) * Processing errors * Committing or rolling back the transaction enclosing the SQL statement * Disconnecting from the MySQL server Because most data access work is done with SQL, the primary tasks for applications that use ODBC are submitting SQL statements and retrieving any results generated by those statements. * *Driver manager:* The Driver Manager is a library that manages communication between application and driver or drivers. It performs the following tasks: * Resolves Data Source Names (DSN). The DSN is a configuration string that identifies a given database driver, database, database host and optionally authentication information that enables an ODBC application to connect to a database using a standardized reference. Because the database connectivity information is identified by the DSN, any ODBC compliant application can connect to the data source using the same DSN reference. This eliminates the need to separately configure each application that needs access to a given database; instead you instruct the application to use a pre-configured DSN. * Loading and unloading of the driver required to access a specific database as defined within the DSN. For example, if you have configured a DSN that connects to a MySQL database then the driver manager will load the Connector/ODBC driver to enable the ODBC API to communicate with the MySQL host. * Processes ODBC function calls or passes them to the driver for processing. * *Connector/ODBC Driver:* The Connector/ODBC driver is a library that implements the functions supported by the ODBC API. It processes ODBC function calls, submits SQL requests to MySQL server, and returns results back to the application. If necessary, the driver modifies an application's request so that the request conforms to syntax supported by MySQL. * *DSN Configuration:* The ODBC configuration file stores the driver and database information required to connect to the server. It is used by the Driver Manager to determine which driver to be loaded according to the definition in the DSN. The driver uses this to read connection parameters based on the DSN specified. For more information, *Note connector-odbc-configuration::. * *MySQL Server:* The MySQL database where the information is stored. The database is used as the source of the data (during queries) and the destination for data (during inserts and updates).  File: manual.info, Node: connector-odbc-driver-manager, Prev: connector-odbc-architecture, Up: connector-odbc-general-information 21.1.2.3 ODBC Driver Managers ............................. An ODBC Driver Manager is a library that manages communication between the ODBC-aware application and any drivers. Its main functionality includes: * Resolving Data Source Names (DSN). * Driver loading and unloading. * Processing ODBC function calls or passing them to the driver. Both Windows and Mac OS X include ODBC driver managers with the operating system. Most ODBC Driver Manager implementations also include an administration application that makes the configuration of DSN and drivers easier. Examples and information on these managers, including Unix ODBC driver managers are listed below: * Microsoft Windows ODBC Driver Manager (`odbc32.dll'), `http://support.microsoft.com/kb/110093'. * Mac OS X includes `ODBC Administrator', a GUI application that provides a simpler configuration mechanism for the Unix iODBC Driver Manager. You can configure DSN and driver information either through ODBC Administrator or through the iODBC configuration files. This also means that you can test ODBC Administrator configurations using the `iodbctest' command. `http://www.apple.com'. * `unixODBC' Driver Manager for Unix (`libodbc.so'). See `http://www.unixodbc.org', for more information. The `unixODBC' Driver Manager includes the Connector/ODBC driver 3.51 in the installation package, starting with version `unixODBC' 2.1.2. * `iODBC' ODBC Driver Manager for Unix (`libiodbc.so'), see `http://www.iodbc.org', for more information.  File: manual.info, Node: connector-odbc-installation, Next: connector-odbc-configuration, Prev: connector-odbc-introduction, Up: connector-odbc 21.1.3 Connector/ODBC Installation ---------------------------------- * Menu: * connector-odbc-installation-binary-windows:: Installing Connector/ODBC from a Binary Distribution on Windows * connector-odbc-installation-binary-unix:: Installing Connector/ODBC from a Binary Distribution on Unix * connector-odbc-installation-binary-macosx:: Installing Connector/ODBC from a Binary Distribution on Mac OS X * connector-odbc-installation-source-windows:: Installing Connector/ODBC from a Source Distribution on Windows * connector-odbc-installation-source-unix:: Installing Connector/ODBC from a Source Distribution on Unix * connector-odbc-installation-source-development:: Installing Connector/ODBC from the Development Source Tree You can install the Connector/ODBC drivers using two different methods, a binary installation and a source installation. The binary installation is the easiest and most straightforward method of installation. Using the source installation methods should only be necessary on platforms where a binary installation package is not available, or in situations where you want to customize or modify the installation process or Connector/ODBC drivers before installation. *Where to Get Connector/ODBC* You can get a copy of the latest version of Connector/ODBC binaries and sources from our Web site at `http://dev.mysql.com/downloads/connector/odbc/'. For more information about Connector/ODBC, visit http://www.mysql.com/products/myodbc/. For more information about licensing, visit http://www.mysql.com/company/legal/licensing/. *Supported Platforms* Connector/ODBC can be used on all major platforms supported by MySQL. You can install it on: * Windows 95, 98, Me, NT, 2000, XP, 2003, Vista and 7 * All Unix-like Operating Systems, including: AIX, Amiga, BSDI, DEC, FreeBSD, HP-UX 10/11, Linux, NetBSD, OpenBSD, OS/2, SGI Irix, Solaris, SunOS, SCO OpenServer, SCO UnixWare, Tru64 Unix * Mac OS X and Mac OS X Server Using a binary distribution offers the most straightforward method for installing Connector/ODBC. If you want more control over the driver, the installation location and or to customize elements of the driver you will need to build and install from the source. If a binary distribution is not available for a particular platform build the driver from the original source code. You can contribute the binaries you create to MySQL by sending a mail message to , so that it becomes available for other users. *Note*: On all non-Windows platforms except Mac OS X, the driver is built against `unixODBC' and is expecting a 2-byte `SQLWCHAR', not 4 bytes as `iODBC' is using. For this reason, the binaries are *only* compatible with `unixODBC' and you will need to recompile the driver against `iODBC' if you wish to use them together. For further information see *Note connector-odbc-driver-manager::. For further instructions: Platform Binary Source Windows *Note Installation *Note Build Instructions: Instructions: connector-odbc-installation-binary-windows.connector-odbc-installation-source-windows. Unix/Linux *Note Installation *Note Build Instructions: Instructions: connector-odbc-installation-binary-unix.connector-odbc-installation-source-unix. Mac OS X *Note Installation Instructions: connector-odbc-installation-binary-macosx.  File: manual.info, Node: connector-odbc-installation-binary-windows, Next: connector-odbc-installation-binary-unix, Prev: connector-odbc-installation, Up: connector-odbc-installation 21.1.3.1 Installing Connector/ODBC from a Binary Distribution on Windows ........................................................................ * Menu: * connector-odbc-installation-binary-windows-installer:: Installing the Windows Connector/ODBC Driver using an installer * connector-odbc-installation-binary-windows-dll:: Installing the Windows Connector/ODBC Driver using the Zipped DLL package Before installing the Connector/ODBC drivers on Windows you should ensure that your Microsoft Data Access Components (MDAC) are up to date. You can obtain the latest version from the Microsoft Data Access and Storage (http://support.microsoft.com/kb/110093) Web site. There are three available distribution types to use when installing for Windows. The contents in each case are identical, it is only the installation method which is different. * Zipped installer consists of a Zipped package containing a standalone installation application. To install from this package, you must unzip the installer, and then run the installation application. See *Note connector-odbc-installation-binary-windows-installer:: to complete the installation. * MSI installer, an installation file that can be used with the installer included in Windows 2000, Windows XP and Windows Server 2003. See *Note connector-odbc-installation-binary-windows-installer:: to complete the installation. * Zipped DLL package, containing the DLL files that need must be manually installed. See *Note connector-odbc-installation-binary-windows-dll:: to complete the installation. *Note*: An OLEDB/ODBC driver for Windows 64-bit is available from Microsoft Downloads (http://www.microsoft.com/downloads/details.aspx?FamilyID=000364db-5e8b-44a8-b9be-ca44d18b059b&displaylang=en).  File: manual.info, Node: connector-odbc-installation-binary-windows-installer, Next: connector-odbc-installation-binary-windows-dll, Prev: connector-odbc-installation-binary-windows, Up: connector-odbc-installation-binary-windows 21.1.3.2 Installing the Windows Connector/ODBC Driver using an installer ........................................................................ The installer packages offer a very simple method for installing the Connector/ODBC drivers. If you have downloaded the zipped installer then you must extract the installer application. The basic installation process is identical for both installers. You should follow these steps to complete the installation: 1. Double-click the standalone installer that you extracted, or the MSI file you downloaded. 2. The MySQL Connector/ODBC 3.51 - Setup Wizard will start. Click the `Next' button to begin the installation process. Connector/ODBC Windows Installer - Welcome 3. You will need to choose the installation type. The Typical installation provides the standard files you will need to connect to a MySQL database using ODBC. The Complete option installs all the available files, including debug and utility components. It is recommended you choose one of these two options to complete the installation. If choose one of these methods, click `Next' and then proceed to step 5. You may also choose a Custom installation, which enables you to select the individual components that you want to install. You have chosen this method, click `Next' and then proceed to step 4. Connector/ODBC Windows Installer - Choosing a Setup type welcome 4. If you have chosen a custom installation, use the pop-ups to select which components to install and then click `Next' to install the necessary files. Connector/ODBC Windows Installer - Custom Installation welcome 5. Once the files have copied to your machine, the installation is complete. Click `Finish' to exit the installer. Connector/ODBC Windows Installer - Completion welcome Now the installation is complete, you can continue to configure your ODBC connections using *Note connector-odbc-configuration::.  File: manual.info, Node: connector-odbc-installation-binary-windows-dll, Prev: connector-odbc-installation-binary-windows-installer, Up: connector-odbc-installation-binary-windows 21.1.3.3 Installing the Windows Connector/ODBC Driver using the Zipped DLL package .................................................................................. If you have downloaded the Zipped DLL package then you must install the individual files required for Connector/ODBC operation manually. Once you have unzipped the installation files, you can either perform this operation by hand, executing each statement individually, or you can use the included Batch file to perform an installation to the default locations. *Note*: The following instructions will only work for 32-bit Windows systems. If you have a 64-bit Windows system you are advised to use the MSI installer, which will install both the 32-bit and 64-bit drivers to the correct locations. To install using the Batch file: 1. Unzip the Connector/ODBC Zipped DLL package. 2. Open a Command Prompt. 3. Change to the directory created when you unzipped the Connector/ODBC Zipped DLL package. 4. Run `Install.bat:' C:\> Install.bat This will copy the necessary files into the default location, and then register the Connector/ODBC driver with the Windows ODBC manager. If you want to copy the files to an alternative location - for example, to run or test different versions of the Connector/ODBC driver on the same machine, then you must copy the files by hand. It is however not recommended to install these files in a nonstandard location. To copy the files by hand to the default installation location use the following steps: 1. Unzip the Connector/ODBC Zipped DLL package. 2. Open a Command Prompt. 3. Change to the directory created when you unzipped the Connector/ODBC Zipped DLL package. 4. Copy the library files to a suitable directory. The default is to copy them into the default Windows system directory `\Windows\System32': C:\> copy lib\myodbc3S.dll \Windows\System32 C:\> copy lib\myodbc3S.lib \Windows\System32 C:\> copy lib\myodbc3.dll \Windows\System32 C:\> copy lib\myodbc3.lib \Windows\System32 5. Copy the Connector/ODBC tools. These must be placed into a directory that is in the system `PATH'. The default is to install these into the Windows system directory `\Windows\System32': C:\> copy bin\myodbc3i.exe \Windows\System32 C:\> copy bin\myodbc3m.exe \Windows\System32 C:\> copy bin\myodbc3c.exe \Windows\System32 6. Optionally copy the help files. For these files to be accessible through the help system, they must be installed in the Windows system directory: C:\> copy doc\*.hlp \Windows\System32 7. Finally, you must register the Connector/ODBC driver with the ODBC manager: C:\> myodbc3i -a -d -t"MySQL ODBC 3.51 Driver;\ DRIVER=myodbc3.dll;SETUP=myodbc3S.dll" You must change the references to the DLL files and command location in the above statement if you have not installed these files into the default location.  File: manual.info, Node: connector-odbc-installation-binary-unix, Next: connector-odbc-installation-binary-macosx, Prev: connector-odbc-installation-binary-windows, Up: connector-odbc-installation 21.1.3.4 Installing Connector/ODBC from a Binary Distribution on Unix ..................................................................... * Menu: * connector-odbc-installation-binary-unix-tarball:: Installing Connector/ODBC from a Binary Tarball Distribution * connector-odbc-installation-binary-unix-rpm:: Installing Connector/ODBC from an RPM Distribution There are two methods available for installing Connector/ODBC on Unix from a binary distribution. For most Unix environments you will need to use the tarball distribution. For Linux systems, there is also an RPM distribution available. *Note*: To install Connector/ODBC 5.1 on Unix you require unixODBC 2.2.12 or later to be installed.  File: manual.info, Node: connector-odbc-installation-binary-unix-tarball, Next: connector-odbc-installation-binary-unix-rpm, Prev: connector-odbc-installation-binary-unix, Up: connector-odbc-installation-binary-unix 21.1.3.5 Installing Connector/ODBC from a Binary Tarball Distribution ..................................................................... To install the driver from a tarball distribution (`.tar.gz' file), download the latest version of the driver for your operating system and follow these steps that demonstrate the process using the Linux version of the tarball: shell> su root shell> gunzip mysql-connector-odbc-3.51.11-i686-pc-linux.tar.gz shell> tar xvf mysql-connector-odbc-3.51.11-i686-pc-linux.tar shell> cd mysql-connector-odbc-3.51.11-i686-pc-linux Read the installation instructions in the `INSTALL' file and execute these commands. Then proceed on to *Note connector-odbc-configuration-dsn-unix::, to configure the DSN for Connector/ODBC. For more information, refer to the `INSTALL' file that comes with your distribution.  File: manual.info, Node: connector-odbc-installation-binary-unix-rpm, Prev: connector-odbc-installation-binary-unix-tarball, Up: connector-odbc-installation-binary-unix 21.1.3.6 Installing Connector/ODBC from an RPM Distribution ........................................................... To install or upgrade Connector/ODBC from an RPM distribution on Linux, simply download the RPM distribution of the latest version of Connector/ODBC and follow the instructions below. Use `su root' to become `root', then install the RPM file. If you are installing for the first time: shell> su root shell> rpm -ivh mysql-connector-odbc-3.51.12.i386.rpm If the driver exists, upgrade it like this: shell> su root shell> rpm -Uvh mysql-connector-odbc-3.51.12.i386.rpm If there is any dependency error for MySQL client library, `libmysqlclient', simply ignore it by supplying the `--nodeps' option, and then make sure the MySQL client shared library is in the path or set through `LD_LIBRARY_PATH'. This installs the driver libraries and related documents to `/usr/local/lib' and `/usr/share/doc/MyODBC', respectively. Proceed onto *Note connector-odbc-configuration-dsn-unix::. To *uninstall* the driver, become `root' and execute an `rpm' command: shell> su root shell> rpm -e mysql-connector-odbc  File: manual.info, Node: connector-odbc-installation-binary-macosx, Next: connector-odbc-installation-source-windows, Prev: connector-odbc-installation-binary-unix, Up: connector-odbc-installation 21.1.3.7 Installing Connector/ODBC from a Binary Distribution on Mac OS X ......................................................................... Mac OS X is based on the FreeBSD operating system, and you can normally use the MySQL network port for connecting to MySQL servers on other hosts. Installing the Connector/ODBC driver enables you to connect to MySQL databases on any platform through the ODBC interface. You should only need to install the Connector/ODBC driver when your application requires an ODBC interface. Applications that require or can use ODBC (and therefore the Connector/ODBC driver) include ColdFusion, Filemaker Pro, 4th Dimension and many other applications. Mac OS X includes its own ODBC manager, based on the `iODBC' manager. Mac OS X includes an administration tool that provides easier administration of ODBC drivers and configuration, updating the underlying `iODBC' configuration files. The method for installing Connector/ODBC on Mac OS X depends on the version on Connector/ODBC you are using. For Connector/ODBC 3.51.14 and later, the package is provided as a compressed tar archive that you must manually install. For Connector/ODBC 3.51.13 and earlier the software was provided on a compressed disk image (`.dmg') file and included an installer. In either case, the driver is designed to work with the iODBC driver manager included with Mac OS X. To install Connector/ODBC 3.51.14 and later: 1. Download the installation file. Note that versions are available for both PowerPC and Intel platforms. 2. Extract the archive: shell> tar zxf mysql-connector-odbc-3.51.16-osx10.4-x86-32bit.tar.gz 3. The directory created will contain two subdirectories, `lib' and `bin'. You need to copy these to a suitable location such as `/usr/local': shell> cp bin/* /usr/local/bin shell> cp lib/* /usr/local/lib 4. Finally, you must register the driver with iODBC using the `myodbc3i' tool you just installed: shell> myodbc3i -a -d -t"MySQL ODBC 3.51 Driver;Driver=/usr/local/lib/libmyodbc3.so;Setup=/usr/local/lib/libmyodbc3S.so" You can verify the installed drivers either by using the ODBC Administrator application or the `myodbc3i' utility: shell> myodbc3i -q -d To install Connector/ODBC 3.51.13 and earlier, follow these steps: 1. Download the file to your computer and double-click the downloaded image file. 2. Within the disk image you will find an installer package (with the `.pkg' extension). Double-click on this file to start the Mac OS X installer. 3. You will be presented with the installer welcome message. Click the `Continue' button to begin the installation process. Connector/ODBC Mac OS X Installer - Installer welcome 4. Please take the time to read the Important Information as it contains guidance on how to complete the installation process. Once you have read the notice and collected the necessary information, click `Continue'. Connector/ODBC Mac OS X Installer - Important Information 5. Connector/ODBC drivers are made available under the GNU General Public License. Please read the license if you are not familiar with it before continuing installation. Click `Continue' to approve the license (you will be asked to confirm that decision) and continue the installation. Connector/ODBC Mac OS X Installer - License 6. Choose a location to install the Connector/ODBC drivers and the ODBC Administrator application. You must install the files onto a drive with an operating system and you may be limited in the choices available. Select the drive you want to use, and then click `Continue'. Connector/ODBC Mac OS X Installer - Choosing a destination 7. The installer will automatically select the files that need to be installed on your machine. Click `Install' to continue. The installer will copy the necessary files to your machine. A progress bar will be shown indicating the installation progress. Connector/ODBC Mac OS X Installer - Installation type 8. When installation has been completed you will get a window like the one shown below. Click `Close' to close and quit the installer. Connector/ODBC Mac OS X Installer - Installation complete  File: manual.info, Node: connector-odbc-installation-source-windows, Next: connector-odbc-installation-source-unix, Prev: connector-odbc-installation-binary-macosx, Up: connector-odbc-installation 21.1.3.8 Installing Connector/ODBC from a Source Distribution on Windows ........................................................................ * Menu: * connector-odbc-installation-source-windows-3-51-building:: Building Connector/ODBC 3.51 * connector-odbc-installation-source-windows-3-51-testing:: Testing You should only need to install Connector/ODBC from source on Windows if you want to change or modify the source or installation. If you are unsure whether to install from source, please use the binary installation detailed in *Note connector-odbc-installation-binary-windows::. Installing Connector/ODBC from source on Windows requires a number of different tools and packages: * MDAC, Microsoft Data Access SDK from `http://support.microsoft.com/kb/110093'. * Suitable C compiler, such as Microsoft Visual C++ or the C compiler included with Microsoft Visual Studio. * Compatible `make' tool. Microsoft's `nmake' is used in the examples in this section. * MySQL client libraries and include files from MySQL 4.0.0 or higher. (Preferably MySQL 4.0.16 or higher). This is required because Connector/ODBC uses new calls and structures that exist only starting from this version of the library. To get the client libraries and include files, visit `http://dev.mysql.com/downloads/'.  File: manual.info, Node: connector-odbc-installation-source-windows-3-51-building, Next: connector-odbc-installation-source-windows-3-51-testing, Prev: connector-odbc-installation-source-windows, Up: connector-odbc-installation-source-windows 21.1.3.9 Building Connector/ODBC 3.51 ..................................... Connector/ODBC source distributions include `Makefiles' that require the `nmake' or other `make' utility. In the distribution, you can find `Makefile' for building the release version and `Makefile_debug' for building debugging versions of the driver libraries and DLLs. To build the driver, use this procedure: 1. Download and extract the sources to a folder, then change directory into that folder. The following command assumes the folder is named `myodbc3-src': C:\> cd myodbc3-src 2. Edit `Makefile' to specify the correct path for the MySQL client libraries and header files. Then use the following commands to build and install the release version: C:\> nmake -f Makefile C:\> nmake -f Makefile install `nmake -f Makefile' builds the release version of the driver and places the binaries in subdirectory called `Release'. `nmake -f Makefile install' installs (copies) the driver DLLs and libraries (`myodbc3.dll', `myodbc3.lib') to your system directory. 3. To build the debug version, use `Makefile_Debug' rather than `Makefile', as shown below: C:\> nmake -f Makefile_debug C:\> nmake -f Makefile_debug install 4. You can clean and rebuild the driver by using: C:\> nmake -f Makefile clean C:\> nmake -f Makefile install *Note*: * Make sure to specify the correct MySQL client libraries and header files path in the Makefiles (set the `MYSQL_LIB_PATH' and `MYSQL_INCLUDE_PATH' variables). The default header file path is assumed to be `C:\mysql\include'. The default library path is assumed to be `C:\mysql\lib\opt' for release DLLs and `C:\mysql\lib\debug' for debug versions. * For the complete usage of `nmake', visit `http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dv_vcce4/html/evgrfRunningNMAKE.asp'. * If you are using the Subversion tree for compiling, all Windows-specific `Makefiles' are named as `Win_Makefile*'.  File: manual.info, Node: connector-odbc-installation-source-windows-3-51-testing, Prev: connector-odbc-installation-source-windows-3-51-building, Up: connector-odbc-installation-source-windows 21.1.3.10 Testing ................. After the driver libraries are copied/installed to the system directory, you can test whether the libraries are properly built by using the samples provided in the `samples' subdirectory: C:\> cd samples C:\> nmake -f Makefile all  File: manual.info, Node: connector-odbc-installation-source-unix, Next: connector-odbc-installation-source-development, Prev: connector-odbc-installation-source-windows, Up: connector-odbc-installation 21.1.3.11 Installing Connector/ODBC from a Source Distribution on Unix ...................................................................... * Menu: * connector-odbc-installation-source-unix-configure-options:: Typical `configure' Options * connector-odbc-installation-source-unix-otheroptions:: Additional configure Options * connector-odbc-installation-source-unix-building:: Building and Compilation * connector-odbc-installation-source-unix-shared-libraries:: Building Shared Libraries * connector-odbc-installation-source-unix-installing:: Installing Driver Libraries * connector-odbc-installation-source-unix-testing:: Testing Connector/ODBC on Unix * connector-odbc-installation-source-unix-macosx:: Building Connector/ODBC from Source on Mac OS X * connector-odbc-installation-source-unix-hpux:: Building Connector/ODBC from Source on HP-UX * connector-odbc-installation-source-unix-aix:: Building Connector/ODBC from Source on AIX You need the following tools to build MySQL from source on Unix: * A working ANSI C++ compiler. `gcc' 2.95.2 or later, SGI C++, and SunPro C++ are some of the compilers that are known to work. * A good `make' program. GNU `make' is always recommended and is sometimes required. * MySQL client libraries and include files from MySQL 4.0.0 or higher. (Preferably MySQL 4.0.16 or higher). This is required because Connector/ODBC uses new calls and structures that exist only starting from this version of the library. To get the client libraries and include files, visit `http://dev.mysql.com/downloads/'. If you have built your own MySQL server or client libraries from source using the GNU autotools, you must use the `--enable-thread-safe-client' option to `configure' when the libraries were built. No special option is needed if you configure with `CMake'. You should also ensure that the `libmysqlclient' library were built and installed as a shared library. * A compatible ODBC manager must be installed. Connector/ODBC is known to work with the `iODBC' and `unixODBC' managers. See *Note connector-odbc-driver-manager::, for more information. * If you are using a character set that isn't compiled into the MySQL client library then you need to install the MySQL character definitions from the `charsets' directory into SHAREDIR (by default, `/usr/local/mysql/share/mysql/charsets'). These should be in place if you have installed the MySQL server on the same machine. See *Note charset::, for more information on character set support. Once you have all the required files, unpack the source files to a separate directory, you then have to run `configure' and build the library using `make'.  File: manual.info, Node: connector-odbc-installation-source-unix-configure-options, Next: connector-odbc-installation-source-unix-otheroptions, Prev: connector-odbc-installation-source-unix, Up: connector-odbc-installation-source-unix 21.1.3.12 Typical `configure' Options ..................................... The `configure' script gives you a great deal of control over how you configure your Connector/ODBC build. Typically you do this using options on the `configure' command line. You can also affect `configure' using certain environment variables. For a list of options and environment variables supported by `configure', run this command: shell> ./configure --help Some of the more commonly used `configure' options are described here: 1. To compile Connector/ODBC, you need to supply the MySQL client include and library files path using the `--with-mysql-path=DIR' option, where DIR is the directory where MySQL is installed. MySQL compile options can be determined by running `DIR/bin/mysql_config'. 2. Supply the standard header and library files path for your ODBC Driver Manager (`iODBC' or `unixODBC'). * If you are using `iODBC' and `iODBC' is not installed in its default location (`/usr/local'), you might have to use the `--with-iodbc=DIR' option, where DIR is the directory where `iODBC' is installed. If the `iODBC' headers do not reside in `DIR/include', you can use the `--with-iodbc-includes=INCDIR' option to specify their location. The applies to libraries. If they are not in `DIR/lib', you can use the `--with-iodbc-libs=LIBDIR' option. * If you are using `unixODBC', use the `--with-unixODBC=DIR' option (case sensitive) to make `configure' look for `unixODBC' instead of `iODBC' by default, DIR is the directory where `unixODBC' is installed. If the `unixODBC' headers and libraries aren't located in `DIR/include' and `DIR/lib', use the `--with-unixODBC-includes=INCDIR' and `--with-unixODBC-libs=LIBDIR' options. 3. You might want to specify an installation prefix other than `/usr/local'. For example, to install the Connector/ODBC drivers in `/usr/local/odbc/lib', use the `--prefix=/usr/local/odbc' option. The final configuration command looks something like this: shell> ./configure --prefix=/usr/local \ --with-iodbc=/usr/local \ --with-mysql-path=/usr/local/mysql  File: manual.info, Node: connector-odbc-installation-source-unix-otheroptions, Next: connector-odbc-installation-source-unix-building, Prev: connector-odbc-installation-source-unix-configure-options, Up: connector-odbc-installation-source-unix 21.1.3.13 Additional configure Options ...................................... There are a number of other options that you need, or want, to set when configuring the Connector/ODBC driver before it is built. * To link the driver with MySQL thread safe client libraries `libmysqlclient_r.so' or `libmysqlclient_r.a', you must specify the following `configure' option: --enable-thread-safe and can be disabled (default) using --disable-thread-safe This option enables the building of the driver thread-safe library `libmyodbc3_r.so' from by linking with MySQL thread-safe client library `libmysqlclient_r.so' (The extensions are OS dependent). If the compilation with the thread-safe option fails, it may be because the correct thread-libraries on the system could not be located. You should set the value of `LIBS' to point to the correct thread library for your system. LIBS="-lpthread" ./configure .. * You can enable or disable the shared and static versions of Connector/ODBC using these options: --enable-shared[=yes/no] --disable-shared --enable-static[=yes/no] --disable-static * By default, all the binary distributions are built as nondebugging versions (configured with `--without-debug'). To enable debugging information, build the driver from a source distribution with the proper configuration option to enable debugging support. See *Note source-configuration-options::. * This option is available only for source trees that have been obtained from the Subversion repository. This option does not apply to the packaged source distributions. By default, the driver is built with the `--without-docs' option. If you would like the documentation to be built, then execute `configure' with: --with-docs  File: manual.info, Node: connector-odbc-installation-source-unix-building, Next: connector-odbc-installation-source-unix-shared-libraries, Prev: connector-odbc-installation-source-unix-otheroptions, Up: connector-odbc-installation-source-unix 21.1.3.14 Building and Compilation .................................. To build the driver libraries, you have to just execute `make'. shell> make If any errors occur, correct them and continue the build process. If you aren't able to build, then send a detailed email to for further assistance.  File: manual.info, Node: connector-odbc-installation-source-unix-shared-libraries, Next: connector-odbc-installation-source-unix-installing, Prev: connector-odbc-installation-source-unix-building, Up: connector-odbc-installation-source-unix 21.1.3.15 Building Shared Libraries ................................... On most platforms, MySQL does not build or support `.so' (shared) client libraries by default. This is based on our experience of problems when building shared libraries. In cases like this, you have to download the MySQL distribution and configure it with these options: --without-server --enable-shared To build shared driver libraries, you must specify the `--enable-shared' option for `configure'. By default, `configure' does not enable this option. If you have configured with the `--disable-shared' option, you can build the `.so' file from the static libraries using the following commands: shell> cd mysql-connector-odbc-3.51.01 shell> make shell> cd driver shell> CC=/usr/bin/gcc \ $CC -bundle -flat_namespace -undefined error \ -o .libs/libmyodbc3-3.51.01.so \ catalog.o connect.o cursor.o dll.o error.o execute.o \ handle.o info.o misc.o myodbc3.o options.o prepare.o \ results.o transact.o utility.o \ -L/usr/local/mysql/lib/mysql/ \ -L/usr/local/iodbc/lib/ \ -lz -lc -lmysqlclient -liodbcinst Make sure to change `-liodbcinst' to `-lodbcinst' if you are using `unixODBC' instead of `iODBC', and configure the library paths accordingly. This builds and places the `libmyodbc3-3.51.01.so' file in the `.libs' directory. Copy this file to the Connector/ODBC library installation directory (`/usr/local/lib' (or the `lib' directory under the installation directory that you supplied with the `--prefix'). shell> cd .libs shell> cp libmyodbc3-3.51.01.so /usr/local/lib shell> cd /usr/local/lib shell> ln -s libmyodbc3-3.51.01.so libmyodbc3.so To build the thread-safe driver library: shell> CC=/usr/bin/gcc \ $CC -bundle -flat_namespace -undefined error -o .libs/libmyodbc3_r-3.51.01.so catalog.o connect.o cursor.o dll.o error.o execute.o handle.o info.o misc.o myodbc3.o options.o prepare.o results.o transact.o utility.o -L/usr/local/mysql/lib/mysql/ -L/usr/local/iodbc/lib/ -lz -lc -lmysqlclient_r -liodbcinst  File: manual.info, Node: connector-odbc-installation-source-unix-installing, Next: connector-odbc-installation-source-unix-testing, Prev: connector-odbc-installation-source-unix-shared-libraries, Up: connector-odbc-installation-source-unix 21.1.3.16 Installing Driver Libraries ..................................... To install the driver libraries, execute the following command: shell> make install That command installs one of the following sets of libraries: For Connector/ODBC 3.51: * `libmyodbc3.so' * `libmyodbc3-3.51.01.so', where 3.51.01 is the version of the driver * `libmyodbc3.a' For thread-safe Connector/ODBC 3.51: * `libmyodbc3_r.so' * `libmyodbc3-3_r.51.01.so' * `libmyodbc3_r.a' For more information on build process, refer to the `INSTALL' file that comes with the source distribution. Note that if you are trying to use the `make' from Sun, you may end up with errors. On the other hand, GNU `gmake' should work fine on all platforms.  File: manual.info, Node: connector-odbc-installation-source-unix-testing, Next: connector-odbc-installation-source-unix-macosx, Prev: connector-odbc-installation-source-unix-installing, Up: connector-odbc-installation-source-unix 21.1.3.17 Testing Connector/ODBC on Unix ........................................ To run the basic samples provided in the distribution with the libraries that you built, use the following command: shell> make test Before running the tests, create the DSN 'myodbc3' in `odbc.ini' and set the environment variable `ODBCINI' to the correct `odbc.ini' file; and MySQL server is running. You can find a sample `odbc.ini' with the driver distribution. You can even modify the `samples/run-samples' script to pass the desired DSN, UID, and PASSWORD values as the command-line arguments to each sample.  File: manual.info, Node: connector-odbc-installation-source-unix-macosx, Next: connector-odbc-installation-source-unix-hpux, Prev: connector-odbc-installation-source-unix-testing, Up: connector-odbc-installation-source-unix 21.1.3.18 Building Connector/ODBC from Source on Mac OS X ......................................................... To build the driver on Mac OS X (Darwin), make use of the following `configure' example: shell> ./configure --prefix=/usr/local --with-unixODBC=/usr/local --with-mysql-path=/usr/local/mysql --disable-shared --enable-gui=no --host=powerpc-apple The command assumes that the `unixODBC' and MySQL are installed in the default locations. If not, configure accordingly. On Mac OS X, `--enable-shared' builds `.dylib' files by default. You can build `.so' files like this: shell> make shell> cd driver shell> CC=/usr/bin/gcc \ $CC -bundle -flat_namespace -undefined error -o .libs/libmyodbc3-3.51.01.so *.o -L/usr/local/mysql/lib/ -L/usr/local/iodbc/lib -liodbcinst -lmysqlclient -lz -lc To build the thread-safe driver library: shell> CC=/usr/bin/gcc \ $CC -bundle -flat_namespace -undefined error -o .libs/libmyodbc3-3.51.01.so *.o -L/usr/local/mysql/lib/ -L/usr/local/iodbc/lib -liodbcinst -lmysqlclienti_r -lz -lc -lpthread Make sure to change the `-liodbcinst' to `-lodbcinst' in case of using `unixODBC' instead of `iODBC' and configure the libraries path accordingly. In Apple's version of GCC, both `cc' and `gcc' are actually symbolic links to `gcc3'. Copy this library to the `$prefix/lib' directory and symlink to `libmyodbc3.so'. You can cross-check the output shared-library properties using this command: shell> otool -LD .libs/libmyodbc3-3.51.01.so  File: manual.info, Node: connector-odbc-installation-source-unix-hpux, Next: connector-odbc-installation-source-unix-aix, Prev: connector-odbc-installation-source-unix-macosx, Up: connector-odbc-installation-source-unix 21.1.3.19 Building Connector/ODBC from Source on HP-UX ...................................................... To build the driver on HP-UX 10.x or 11.x, make use of the following `configure' example: If using `cc': shell> CC="cc" \ CFLAGS="+z" \ LDFLAGS="-Wl,+b:-Wl,+s" \ ./configure --prefix=/usr/local --with-unixodbc=/usr/local --with-mysql-path=/usr/local/mysql/lib/mysql --enable-shared --enable-thread-safe If using `gcc': shell> CC="gcc" \ LDFLAGS="-Wl,+b:-Wl,+s" \ ./configure --prefix=/usr/local --with-unixodbc=/usr/local --with-mysql-path=/usr/local/mysql --enable-shared --enable-thread-safe Once the driver is built, cross-check its attributes using `chatr .libs/libmyodbc3.sl' to determine whether you need to have set the MySQL client library path using the `SHLIB_PATH' environment variable. For static versions, ignore all shared-library options and run `configure' with the `--disable-shared' option.  File: manual.info, Node: connector-odbc-installation-source-unix-aix, Prev: connector-odbc-installation-source-unix-hpux, Up: connector-odbc-installation-source-unix 21.1.3.20 Building Connector/ODBC from Source on AIX .................................................... To build the driver on AIX, make use of the following `configure' example: shell> ./configure --prefix=/usr/local --with-unixodbc=/usr/local --with-mysql-path=/usr/local/mysql --disable-shared --enable-thread-safe *Note*: For more information about how to build and set up the static and shared libraries across the different platforms refer to ' Using static and shared libraries across platforms (http://www.fortran-2000.com/ArnaudRecipes/sharedlib.html)'.  File: manual.info, Node: connector-odbc-installation-source-development, Prev: connector-odbc-installation-source-unix, Up: connector-odbc-installation 21.1.3.21 Installing Connector/ODBC from the Development Source Tree .................................................................... *Caution*: You should read this section only if you are interested in helping us test our new code. If you just want to get MySQL Connector/ODBC up and running on your system, you should use a standard release distribution. To obtain the most recent development source tree, you first need to download and install Bazaar. You can obtain Bazaar from the Bazaar VCS Web site (http://bazaar-vcs.org). Bazaar is supported by any platform that supports Python, and is therefore compatible with any Linux, Unix, Windows or Mac OS X host. Instructions for downloading and installing Bazaar on the different platforms are available on the Bazaar Web site. To build from the source trees, you need the following tools: * autoconf 2.52 (or newer) * automake 1.4 (or newer) * libtool 1.4 (or newer) * m4 The most recent development source tree is available from our public Subversion trees at `http://dev.mysql.com/tech-resources/sources.html'. To check out out the Connector/ODBC sources, change to the directory where you want the copy of the Connector/ODBC tree to be stored, then use the following command: shell> bzr branch lp:myodbc You should now have a copy of the entire Connector/ODBC source tree in the directory `connector-odbc3'. To build from this source tree on Unix or Linux follow these steps: shell> cd myodbc shell> aclocal shell> autoheader shell> libtoolize -c -f shell> autoconf shell> automake; shell> ./configure # Add your favorite options here shell> make For more information on how to build, refer to the `INSTALL' file located in the same directory. For more information on options to `configure', see *Note connector-odbc-installation-source-unix-configure-options:: When the build is done, run `make install' to install the Connector/ODBC 3.51 driver on your system. If you have gotten to the `make' stage and the distribution does not compile, please report it to . On Windows, make use of Windows Makefiles `WIN-Makefile' and `WIN-Makefile_debug' in building the driver. For more information, see *Note connector-odbc-installation-source-windows::. After the initial checkout operation to get the source tree, you should run `bzr pull' periodically to update your source according to the latest version.  File: manual.info, Node: connector-odbc-configuration, Next: connector-odbc-examples, Prev: connector-odbc-installation, Up: connector-odbc 21.1.4 Connector/ODBC Configuration ----------------------------------- * Menu: * connector-odbc-configuration-dsn:: Data Source Names * connector-odbc-configuration-connection-parameters:: Connector/ODBC Connection Parameters * connector-odbc-configuration-dsn-windows:: Configuring a Connector/ODBC DSN on Windows * connector-odbc-configuration-dsn-macosx:: Configuring a Connector/ODBC DSN on Mac OS X * connector-odbc-configuration-dsn-unix:: Configuring a Connector/ODBC DSN on Unix * connector-odbc-configuration-connection-without-dsn:: Connecting Without a Predefined DSN * connector-odbc-configuration-connection-pooling:: ODBC Connection Pooling * connector-odbc-configuration-trace:: Getting an ODBC Trace File Before you connect to a MySQL database using the Connector/ODBC driver you must configure an ODBC _Data Source Name_. The DSN associates the various configuration parameters required to communicate with a database to a specific name. You use the DSN in an application to communicate with the database, rather than specifying individual parameters within the application itself. DSN information can be user specific, system specific, or provided in a special file. ODBC data source names are configured in different ways, depending on your platform and ODBC driver.  File: manual.info, Node: connector-odbc-configuration-dsn, Next: connector-odbc-configuration-connection-parameters, Prev: connector-odbc-configuration, Up: connector-odbc-configuration 21.1.4.1 Data Source Names .......................... A Data Source Name associates the configuration parameters for communicating with a specific database. Generally a DSN consists of the following parameters: * Name * Host Name * Database Name * Login * Password In addition, different ODBC drivers, including Connector/ODBC, may accept additional driver-specific options and parameters. There are three types of DSN: * A _System DSN_ is a global DSN definition that is available to any user and application on a particular system. A System DSN can normally only be configured by a systems administrator, or by a user who has specific permissions that let them create System DSNs. * A _User DSN_ is specific to an individual user, and can be used to store database connectivity information that the user regularly uses. * A _File DSN_ uses a simple file to define the DSN configuration. File DSNs can be shared between users and machines and are therefore more practical when installing or deploying DSN information as part of an application across many machines. DSN information is stored in different locations depending on your platform and environment.  File: manual.info, Node: connector-odbc-configuration-connection-parameters, Next: connector-odbc-configuration-dsn-windows, Prev: connector-odbc-configuration-dsn, Up: connector-odbc-configuration 21.1.4.2 Connector/ODBC Connection Parameters ............................................. You can specify the parameters in the following tables for Connector/ODBC when configuring a DSN. Users on Windows can use the Options and Advanced panels when configuring a DSN to set these parameters; see the table for information on which options relate to which fields and check boxes. On Unix and Mac OS X, use the parameter name and value as the keyword/value pair in the DSN configuration. Alternatively, you can set these parameters within the `InConnectionString' argument in the `SQLDriverConnect()' call. Parameter Default Value Comment `user' ODBC The user name used to connect to MySQL. `uid' ODBC Synonymous with `user'. Added in 3.51.16. `server' `localhost' The host name of the MySQL server. `database' The default database. `option' 0 Options that specify how Connector/ODBC should work. See below. `port' 3306 The TCP/IP port to use if `server' is not `localhost'. `initstmt' Initial statement. A statement to execute when connecting to MySQL. In version 3.51 the parameter is called `stmt'. Note, the driver supports the initial statement being executed only at the time of the initial connection. `password' The password for the `user' account on `server'. `pwd' Synonymous with `password'. Added in 3.51.16. `socket' The Unix socket file or Windows named pipe to connect to if `server' is `localhost'. `sslca' The path to a file with a list of trust SSL CAs. Added in 3.51.16. `sslcapath' The path to a directory that contains trusted SSL CA certificates in PEM format. Added in 3.51.16. `sslcert' The name of the SSL certificate file to use for establishing a secure connection. Added in 3.51.16. `sslcipher' A list of permissible ciphers to use for SSL encryption. The cipher list has the same format as the `openssl ciphers' command Added in 3.51.16. `sslkey' The name of the SSL key file to use for establishing a secure connection. Added in 3.51.16. `charset' The character set to use for the connection. Added in 3.51.17. `sslverify' If set to 1, the SSL certificate will be verified when used with the MySQL connection. If not set, then the default behavior is to ignore SSL certificate verification. `readtimeout' The timeout in seconds for attempts to read from the server. Each attempt uses this timeout value and there are retries if necessary, so the total effective timeout value is three times the option value. You can set the value so that a lost connection can be detected earlier than the TCP/IP `Close_Wait_Timeout' value of 10 minutes. This option works only for TCP/IP connections, and only for Windows prior to MySQL 5.1.12. Corresponds to the `MYSQL_OPT_READ_TIMEOUT' option of the MySQL Client Library. This option was added in Connector/ODBC 3.51.27. `writetimeout' The timeout in seconds for attempts to write to the server. Each attempt uses this timeout value and there are `net_retry_count' retries if necessary, so the total effective timeout value is `net_retry_count' times the option value. This option works only for TCP/IP connections, and only for Windows prior to MySQL 5.1.12. Corresponds to the `MYSQL_OPT_WRITE_TIMEOUT' option of the MySQL Client Library. This option was added in Connector/ODBC 3.51.27. `interactive' Enables the `CLIENT_INTERACTIVE' connection option of `mysql_real_connect'. *Note*: The SSL configuration parameters can also be automatically loaded from a `my.ini' or `my.cnf' file. The `option' argument is used to tell Connector/ODBC that the client isn't 100% ODBC compliant. On Windows, you normally select options by toggling the check boxes in the connection screen, but you can also select them in the `option' argument. The following options are listed in the order in which they appear in the Connector/ODBC connect screen. Flagname GUI Option Description `FLAG_FIELD_LENGTH'Do not The client cannot handle that Optimize Connector/ODBC returns the real width of a Column Width column. This option was removed in 3.51.18. `FLAG_FOUND_ROWS'Return The client cannot handle that MySQL Matching Rows returns the true value of affected rows. If this flag is set, MySQL returns `found rows' instead. You must have MySQL 3.21.14 or newer to get this to work. `FLAG_DEBUG' Trace Driver Make a debug log in `C:\myodbc.log' on Calls To Windows, or `/tmp/myodbc.log' on Unix myodbc.log variants. This option was removed in Connector/ODBC 3.51.18. `FLAG_BIG_PACKETS'Allow Big Do not set any packet limit for results Results and bind parameters. Without this option, parameter binding will be truncated to 255 characters. `FLAG_NO_PROMPT'Do not Prompt Do not prompt for questions even if driver Upon Connect would like to prompt. `FLAG_DYNAMIC_CURSOR'Enable Enable or disable the dynamic cursor Dynamic Cursor support. `FLAG_NO_SCHEMA'Ignore # in Ignore use of database name in Table Name DB_NAME.TBL_NAME.COL_NAME. `FLAG_NO_DEFAULT_CURSOR'User Manager Force use of ODBC manager cursors Cursors (experimental). `FLAG_NO_LOCALE'Do not Use Disable the use of extended fetch Set Locale (experimental). `FLAG_PAD_SPACE'Pad Char To Pad *Note `CHAR': char. columns to full Full Length column length. `FLAG_FULL_COLUMN_NAMES'Return Table `SQLDescribeCol()' returns fully qualified Names for column names. SQLDescribeCol `FLAG_COMPRESSED_PROTO'Use Use the compressed client/server protocol. Compressed Protocol `FLAG_IGNORE_SPACE'Ignore Space Tell server to ignore space after function After name and before ``('' (needed by Function Names PowerBuilder). This makes all function names keywords. `FLAG_NAMED_PIPE'Force Use of Connect with named pipes to a *Note Named Pipes `mysqld': mysqld. server running on NT. `FLAG_NO_BIGINT'Change BIGINT Change *Note `BIGINT': numeric-types. Columns to Int columns to *Note `INT': numeric-types. columns (some applications cannot handle *Note `BIGINT': numeric-types.). `FLAG_NO_CATALOG'No Catalog Forces results from the catalog functions, such as `SQLTables', to always return `NULL' and the driver to report that catalogs are not supported. `FLAG_USE_MYCNF'Read Options Read parameters from the `[client]' and From `my.cnf' `[odbc]' groups from `my.cnf'. `FLAG_SAFE' Safe Add some extra safety checks. `FLAG_NO_TRANSACTIONS'Disable Disable transactions. transactions `FLAG_LOG_QUERY'Save queries Enable query logging to to `c:\myodbc.sql'(`/tmp/myodbc.sql') file. `myodbc.sql' (Enabled only in debug mode.) `FLAG_NO_CACHE'Do not Cache Do not cache the results locally in the Result driver, instead read from server (*Note (forward only `mysql_use_result()': mysql-use-result.). cursors) This works only for forward-only cursors. This option is very important in dealing with large tables when you do not want the driver to cache the entire result set. `FLAG_FORWARD_CURSOR'Force Use Of Force the use of `Forward-only' cursor Forward Only type. In case of applications setting the Cursors default static/dynamic cursor type, and one wants the driver to use noncache result sets, then this option ensures the forward-only cursor behavior. `FLAG_AUTO_RECONNECT'Enable Enables auto-reconnection functionality. auto-reconnect.You should not use this option with transactions, since a auto reconnection during a incomplete transaction may cause corruption. Note that an auto-reconnected connection will not inherit the same settings and environment as the original. This option was added in Connector/ODBC 3.51.13. `FLAG_AUTO_IS_NULL'Flag Auto Is When `FLAG_AUTO_IS_NULL' is set, the Null driver does not change the default value of `sql_auto_is_null', leaving it at 1, so you get the MySQL default, not the SQL standard behavior. When `FLAG_AUTO_IS_NULL' is not set, the driver changes the default value of `SQL_AUTO_IS_NULL' to 0 after connecting, so you get the SQL standard, not the MySQL default behavior. Thus, omitting the flag disables the compatibility option and forces SQL standard behavior. See `IS NULL'. This option was added in Connector/ODBC 3.51.13. `FLAG_ZERO_DATE_TO_MIN'Return Translates zero dates (`XXXX-00-00') into SQL_NULL_DATA the minimum date values supported by ODBC, for zero date `XXXX-01-01'. This resolves an issue where some statements will not work because the date returned and the minimum ODBC date value are incompatible. This option was added in Connector/ODBC 3.51.17. `FLAG_MIN_DATE_TO_ZERO'Bind minimal Translates the minimum ODBC date value date as zero (`XXXX-01-01') to the zero date format date supported by MySQL (`XXXX-00-00'). This resolves an issue where some statements will not work because the date returned and the minimum ODBC date value are incompatible. This option was added in Connector/ODBC 3.51.17. `FLAG_MULTI_STATEMENTS'Allow Enables support for batched statements. multiple This option was added in Connector/ODBC statements 3.51.18. `FLAG_COLUMN_SIZE_S32'Limit column Limits the column size to a signed 32-bit size to value to prevent problems with larger 32-bit value column sizes in applications that do not support them. This option is automatically enabled when working with ADO applications. This option was added in Connector/ODBC 3.51.22. `FLAG_NO_BINARY_RESULT'Always handle When set this option disables charset 63 binary for columns with an empty `org_table'. function This option was added in Connector/ODBC results as 3.51.26. character data `FLAG_NO_INFORMATION_SCHEMA' Tells catalog functions not to use `INFORMATION_SCHEMA', but rather use legacy algorithms. The trade-off here is usually speed for information quality. Using `INFORMATION_SCHEMA' is often slow, but the information obtained is more complete. `FLAG_DFLT_BIGINT_BIND_STR' Causes `BIGINT' parameters to be bound as strings. Microsoft Access treats `BIGINT' as a string on linked tables. The value is read correctly, but bound as a string. This option is used automatically if the driver is used by Microsoft Access. To select multiple options, add together their values. *Note*: From version of MySQL Connector/ODBC 5.1.6 onwards, it is possible to use the flag name directly as a parameter in the connection string, by using the flag name without the FLAG_ prefix. So, in addition to using the `options' parameter with various flags set, it is now possible to use the flags directly as parameters. For example, `FIELD_LENGTH', `FOUND_ROWS' and `DEBUG' could all be used as parameters. The following table shows some recommended `option' values for various configurations. Configuration Option Value Microsoft Access, Visual Basic 3 Driver trace generation (Debug mode) 4 Microsoft Access (with improved DELETE queries) 35 Large tables with too many rows 2049 Sybase PowerBuilder 135168 Query log generation (Debug mode) 524288 Generate driver trace as well as query log (Debug mode) 524292 Large tables with no-cache results 3145731  File: manual.info, Node: connector-odbc-configuration-dsn-windows, Next: connector-odbc-configuration-dsn-macosx, Prev: connector-odbc-configuration-connection-parameters, Up: connector-odbc-configuration 21.1.4.3 Configuring a Connector/ODBC DSN on Windows .................................................... * Menu: * connector-odbc-configuration-dsn-windows-3-51:: Configuring a Connector/ODBC 3.51 DSN on Windows * connector-odbc-configuration-dsn-windows-5-1:: Configuring a Connector/ODBC 5.1 DSN on Windows * connector-odbc-configuration-dsn-windows-problems:: Errors and Debugging The `ODBC Data Source Administrator' within Windows enables you to create DSNs, check driver installation and configure ODBC systems such as tracing (used for debugging) and connection pooling. Different editions and versions of Windows store the `ODBC Data Source Administrator' in different locations depending on the version of Windows that you are using. To open the `ODBC Data Source Administrator' in Windows Server 2003: *Tip*: Because it is possible to create DSN using either the 32-bit or 64-bit driver, but using the same DNS identifier, it is advisable to include the driver being used within the DSN identifier. This will help you to identify the DSN when using it from applications such as Excel that are only compatible with the 32-bit driver. For example, you might add `Using32bitCODBC' to the DSN identifier for the 32-bit interface and `Using64bitCODBC' for those using the 64-bit Connector/ODBC driver. 1. On the `Start' menu, choose `Administrative Tools', and then click `Data Sources (ODBC)'. To open the `ODBC Data Source Administrator' in Windows 2000 Server or Windows 2000 Professional: 1. On the `Start' menu, choose `Settings', and then click `Control Panel'. 2. In `Control Panel', click `Administrative Tools'. 3. In `Administrative Tools', click `Data Sources (ODBC)'. To open the `ODBC Data Source Administrator' on Windows XP: 1. On the `Start' menu, click `Control Panel'. 2. In the `Control Panel' when in `Category View' click `Performance and Maintenance' and then click `Administrative Tools.'. If you are viewing the `Control Panel' in `Classic View', click `Administrative Tools'. 3. In `Administrative Tools', click `Data Sources (ODBC)'. Irrespective of your Windows version, you should be presented the `ODBC Data Source Administrator' window: `ODBC Data Source Administrator' Dialog Within Windows XP, you can add the `Administrative Tools' folder to your `Start' menu to make it easier to locate the ODBC Data Source Administrator. To do this: 1. Right-click the `Start' menu. 2. Select `Properties'. 3. Click `Customize...'. 4. Select the `Advanced' tab. 5. Within `Start menu items', within the `System Administrative Tools' section, select `Display on the All Programs menu'. Within both Windows Server 2003 and Windows XP you may want to permanently add the `ODBC Data Source Administrator' to your `Start' menu. To do this, locate the `Data Sources (ODBC)' icon using the methods shown, then right-click on the icon and then choose `Pin to Start Menu'. The interfaces for the 3.51 and 5.1 versions of the Connector/ODBC driver are different, although the fields and information that you need to enter remain the same. To configure a DSN using Connector/ODBC 3.51.x or Connector/ODBC 5.1.0, see *Note connector-odbc-configuration-dsn-windows-3-51::. To configure a DSN using Connector/ODBC 5.1.1 or later, see *Note connector-odbc-configuration-dsn-windows-5-1::.  File: manual.info, Node: connector-odbc-configuration-dsn-windows-3-51, Next: connector-odbc-configuration-dsn-windows-5-1, Prev: connector-odbc-configuration-dsn-windows, Up: connector-odbc-configuration-dsn-windows 21.1.4.4 Configuring a Connector/ODBC 3.51 DSN on Windows ......................................................... To add and configure a new Connector/ODBC data source on Windows, use the `ODBC Data Source Administrator': 1. Open the `ODBC Data Source Administrator'. 2. To create a System DSN (which will be available to all users) , select the `System DSN' tab. To create a User DSN, which will be unique only to the current user, click the `Add...' button. 3. You will need to select the ODBC driver for this DSN. `MySQL ODBC Driver Selection' Dialog Select `MySQL ODBC 3.51 Driver', then click `Finish'. 4. You now need to configure the specific fields for the DSN you are creating through the `Add Data Source Name' dialog. `Add Data Source Name' Dialog for Connector/ODBC 3.51.x In the `Data Source Name' box, enter the name of the data source you want to access. It can be any valid name that you choose. 5. In the `Description' box, enter some text to help identify the connection. 6. In the `Server' field, enter the name of the MySQL server host that you want to access. By default, it is `localhost'. 7. In the `User' field, enter the user name to use for this connection. 8. In the `Password' field, enter the corresponding password for this connection. 9. The `Database' pop-up should automatically populate with the list of databases that the user has permissions to access. 10. Click `OK' to save the DSN. A completed DSN configuration may look like this: Sample`MySQL ODBC DSN Configuration' Dialog You can verify the connection using the parameters you have entered by clicking the `Test' button. If the connection could be made successfully, you will be notified with a `Success; connection was made!' dialog. If the connection failed, you can obtain more information on the test and why it may have failed by clicking the `Diagnostics...' button to show additional error messages. You can configure a number of options for a specific DSN by using either the `Connect Options' or `Advanced' tabs in the DSN configuration dialog. Connector/ODBC Connect Options Dialog The three options you can configure are: * `Port' sets the TCP/IP port number to use when communicating with MySQL. Communication with MySQL uses port 3306 by default. If your server is configured to use a different TCP/IP port, you must specify that port number here. * `Socket' sets the name or location of a specific socket or Windows pipe to use when communicating with MySQL. * `Initial Statement' defines an SQL statement that will be executed when the connection to MySQL is opened. You can use this to set MySQL options for your connection, such as disabling autocommit. * `Character Set' is a pop-up list from which you can select the default character set to be used with this connection. The Character Set option was added in 3.5.17. The `Advanced' tab enables you to configure Connector/ODBC connection parameters. Refer to *Note connector-odbc-configuration-connection-parameters::, for information about the meaning of these options. Connector/ODBC Connection Advanced Dialog  File: manual.info, Node: connector-odbc-configuration-dsn-windows-5-1, Next: connector-odbc-configuration-dsn-windows-problems, Prev: connector-odbc-configuration-dsn-windows-3-51, Up: connector-odbc-configuration-dsn-windows 21.1.4.5 Configuring a Connector/ODBC 5.1 DSN on Windows ........................................................ The DSN configuration when using Connector/ODBC 5.1.1 and later has a slightly different layout. Also, due to the native Unicode support within Connector/ODBC 5.1, you no longer need to specify the initial character set to be used with your connection. To configure a DSN using the Connector/ODBC 5.1.1 or later driver: 1. Open the `ODBC Data Source Administrator'. 2. To create a System DSN (which will be available to all users) , select the `System DSN' tab. To create a User DSN, which will be unique only to the current user, click the `Add...' button. 3. You will need to select the ODBC driver for this DSN. `MySQL ODBC Driver Selection' Dialog Select `MySQL ODBC 5.1 Driver', then click `Finish'. 4. You now need to configure the specific fields for the DSN you are creating through the `Connection Parameters' dialog. `Add Data Source Name' Dialog for Connector/ODBC 5.1 In the `Data Source Name' box, enter the name of the data source you want to access. It can be any valid name that you choose. 5. In the `Description' box, enter some text to help identify the connection. 6. In the `Server' field, enter the name of the MySQL server host that you want to access. By default, it is `localhost'. 7. In the `User' field, enter the user name to use for this connection. 8. In the `Password' field, enter the corresponding password for this connection. 9. The `Database' pop-up should automatically populate with the list of databases that the user has permissions to access. 10. To communicate over a different TCP/IP port than the default (3306), change the value of the `Port'. 11. Click `OK' to save the DSN. You can verify the connection using the parameters you have entered by clicking the `Test' button. If the connection could be made successfully, you will be notified with a `Success; connection was made!' dialog. You can configure a number of options for a specific DSN by using the `Details' button. Connector/ODBC Connect Options Dialog The `Details' button opens a tabbed display which enables you to set additional options: * `Flags 1', `Flags 2', and `Flags 3' enable you to select the additional flags for the DSN connection. For more information on these flags, see *Note connector-odbc-configuration-connection-parameters::. * `Debug' enables you to enable ODBC debugging to record the queries you execute through the DSN to the `myodbc.sql' file. For more information, see *Note connector-odbc-configuration-trace::. * `SSL Settings' configures the additional options required for using the Secure Sockets Layer (SSL) when communicating with MySQL server. Note that you must have enabled SSL and configured the MySQL server with suitable certificates to communicate over SSL. Connector/ODBC 5.1 SSL Configuration The `Advanced' tab enables you to configure Connector/ODBC connection parameters. Refer to *Note connector-odbc-configuration-connection-parameters::, for information about the meaning of these options.  File: manual.info, Node: connector-odbc-configuration-dsn-windows-problems, Prev: connector-odbc-configuration-dsn-windows-5-1, Up: connector-odbc-configuration-dsn-windows 21.1.4.6 Errors and Debugging ............................. This section answers Connector/ODBC connection-related questions. * *While configuring a Connector/ODBC DSN, a `Could Not Load Translator or Setup Library' error occurs* For more information, refer to MS KnowledgeBase Article(Q260558) (http://support.microsoft.com/default.aspx?scid=kb;EN-US;q260558). Also, make sure you have the latest valid `ctl3d32.dll' in your system directory. * On Windows, the default `myodbc3.dll' is compiled for optimal performance. If you want to debug Connector/ODBC 3.51 (for example, to enable tracing), you should instead use `myodbc3d.dll'. To install this file, copy `myodbc3d.dll' over the installed `myodbc3.dll' file. Make sure to revert back to the release version of the driver DLL once you are done with the debugging because the debug version may cause performance issues. Note that the `myodbc3d.dll' isn't included in Connector/ODBC 3.51.07 through 3.51.11. If you are using one of these versions, you should copy that DLL from a previous version (for example, 3.51.06).  File: manual.info, Node: connector-odbc-configuration-dsn-macosx, Next: connector-odbc-configuration-dsn-unix, Prev: connector-odbc-configuration-dsn-windows, Up: connector-odbc-configuration 21.1.4.7 Configuring a Connector/ODBC DSN on Mac OS X ..................................................... To configure a DSN on Mac OS X you can either use the `myodbc3i' utility, edit the `odbc.ini' file within the `Library/ODBC' directory of the user or the should use the ODBC Administrator. If you have Mac OS X 10.2 or earlier, refer to *Note connector-odbc-configuration-dsn-unix::. Select whether you want to create a User DSN or a System DSN. If you want to add a System DSN, you may need to authenticate with the system. You must click the padlock and enter a user and password with administrator privileges. For correct operation of ODBC Administrator, you should ensure that the `/Library/ODBC/odbc.ini' file used to set up ODBC connectivity and DSNs are writable by the `admin' group. If this file is not writable by this group then the ODBC Administrator may fail, or may appear to have worked but not generated the correct entry. *Warning*: There are known issues with the OS X ODBC Administrator and Connector/ODBC that may prevent you from creating a DSN using this method. In this case you should use the command-line or edit the `odbc.ini' file directly. Note that existing DSNs or those that you create using the `myodbc3i' or `myodbc-installer' tool can still be checked and edited using ODBC Administrator. To create a DSN using the `myodbc3i' utility, you need only specify the DSN type and the DSN connection string. For example: shell> myodbc3i -a -s -t"DSN=mydb;DRIVER=MySQL ODBC 3.51 Driver;SERVER=mysql;USER=username;PASSWORD=pass" To use ODBC Administrator: 1. Open the ODBC Administrator from the `Utilities' folder in the `Applications' folder. `ODBC Administrator Main Panel' Dialog 2. On the User DSN or System DSN panel, click `Add.' 3. Select the Connector/ODBC driver and click `OK'. 4. You will be presented with the `Data Source Name' dialog. Enter The `Data Source Name' and an optional `Description' for the DSN. `ODBC Administrator Add DSN' Dialog 5. Click `Add' to add a new keyword/value pair to the panel. You should configure at least four pairs to specify the `server', `username', `password' and `database' connection parameters. See *Note connector-odbc-configuration-connection-parameters::. 6. Click `OK' to add the DSN to the list of configured data source names. A completed DSN configuration may look like this: `ODBC Administrator Sample DSN' Dialog You can configure other ODBC options in your DSN by adding further keyword/value pairs and setting the corresponding values. See *Note connector-odbc-configuration-connection-parameters::.  File: manual.info, Node: connector-odbc-configuration-dsn-unix, Next: connector-odbc-configuration-connection-without-dsn, Prev: connector-odbc-configuration-dsn-macosx, Up: connector-odbc-configuration 21.1.4.8 Configuring a Connector/ODBC DSN on Unix ................................................. On `Unix', you configure DSN entries directly in the `odbc.ini' file. Here is a typical `odbc.ini' file that configures `myodbc3' as the DSN name for Connector/ODBC 3.51: ; ; odbc.ini configuration for Connector/ODBC and Connector/ODBC 3.51 drivers ; [ODBC Data Sources] myodbc3 = MyODBC 3.51 Driver DSN [myodbc3] Driver = /usr/local/lib/libmyodbc3.so Description = Connector/ODBC 3.51 Driver DSN SERVER = localhost PORT = USER = root Password = Database = test OPTION = 3 SOCKET = [Default] Driver = /usr/local/lib/libmyodbc3.so Description = Connector/ODBC 3.51 Driver DSN SERVER = localhost PORT = USER = root Password = Database = test OPTION = 3 SOCKET = Refer to the *Note connector-odbc-configuration-connection-parameters::, for the list of connection parameters that can be supplied. *Note*: If you are using `unixODBC', you can use the following tools to set up the DSN: * ODBCConfig GUI tool(HOWTO: ODBCConfig (http://www.unixodbc.org/config.html)) * odbcinst In some cases when using `unixODBC', you might get this error: Data source name not found and no default driver specified If this happens, make sure the `ODBCINI' and `ODBCSYSINI' environment variables are pointing to the right `odbc.ini' file. For example, if your `odbc.ini' file is located in `/usr/local/etc', set the environment variables like this: export ODBCINI=/usr/local/etc/odbc.ini export ODBCSYSINI=/usr/local/etc  File: manual.info, Node: connector-odbc-configuration-connection-without-dsn, Next: connector-odbc-configuration-connection-pooling, Prev: connector-odbc-configuration-dsn-unix, Up: connector-odbc-configuration 21.1.4.9 Connecting Without a Predefined DSN ............................................ You can connect to the MySQL server using SQLDriverConnect, by specifying the `DRIVER' name field. Here are the connection strings for Connector/ODBC using DSN-Less connections: *For Connector/ODBC 3.51:* ConnectionString = "DRIVER={MySQL ODBC 3.51 Driver};\ SERVER=localhost;\ DATABASE=test;\ USER=venu;\ PASSWORD=venu;\ OPTION=3;" If your programming language converts backslash followed by whitespace to a space, it is preferable to specify the connection string as a single long string, or to use a concatenation of multiple strings that does not add spaces in between. For example: ConnectionString = "DRIVER={MySQL ODBC 3.51 Driver};" "SERVER=localhost;" "DATABASE=test;" "USER=venu;" "PASSWORD=venu;" "OPTION=3;" Note Note that on Mac OS X you may need to specify the full path to the Connector/ODBC driver library. Refer to the *Note connector-odbc-configuration-connection-parameters::, for the list of connection parameters that can be supplied.  File: manual.info, Node: connector-odbc-configuration-connection-pooling, Next: connector-odbc-configuration-trace, Prev: connector-odbc-configuration-connection-without-dsn, Up: connector-odbc-configuration 21.1.4.10 ODBC Connection Pooling ................................. Connection pooling enables the ODBC driver to re-use existing connections to a given database from a pool of connections, instead of opening a new connection each time the database is accessed. By enabling connection pooling you can improve the overall performance of your application by lowering the time taken to open a connection to a database in the connection pool. For more information about connection pooling: `http://support.microsoft.com/default.aspx?scid=kb;EN-US;q169470'.  File: manual.info, Node: connector-odbc-configuration-trace, Prev: connector-odbc-configuration-connection-pooling, Up: connector-odbc-configuration 21.1.4.11 Getting an ODBC Trace File .................................... * Menu: * connector-odbc-configuration-trace-windows:: Enabling ODBC Tracing on Windows * connector-odbc-configuration-trace-macosx:: Enabling ODBC Tracing on Mac OS X * connector-odbc-configuration-trace-unix:: Enabling ODBC Tracing on Unix * connector-odbc-configuration-trace-log:: Enabling a Connector/ODBC Log If you encounter difficulties or problems with Connector/ODBC, you should start by making a log file from the `ODBC Manager' and Connector/ODBC. This is called _tracing_, and is enabled through the ODBC Manager. The procedure for this differs for Windows, Mac OS X and Unix.  File: manual.info, Node: connector-odbc-configuration-trace-windows, Next: connector-odbc-configuration-trace-macosx, Prev: connector-odbc-configuration-trace, Up: connector-odbc-configuration-trace 21.1.4.12 Enabling ODBC Tracing on Windows .......................................... To enable the trace option on Windows: 1. The `Tracing' tab of the ODBC Data Source Administrator dialog box enables you to configure the way ODBC function calls are traced. ODBC Data Source Administrator Tracing Dialog 2. When you activate tracing from the `Tracing' tab, the `Driver Manager' logs all ODBC function calls for all subsequently run applications. 3. ODBC function calls from applications running before tracing is activated are not logged. ODBC function calls are recorded in a log file you specify. 4. Tracing ceases only after you click `Stop Tracing Now'. Remember that while tracing is on, the log file continues to increase in size and that tracing affects the performance of all your ODBC applications.  File: manual.info, Node: connector-odbc-configuration-trace-macosx, Next: connector-odbc-configuration-trace-unix, Prev: connector-odbc-configuration-trace-windows, Up: connector-odbc-configuration-trace 21.1.4.13 Enabling ODBC Tracing on Mac OS X ........................................... To enable the trace option on Mac OS X 10.3 or later you should use the `Tracing' tab within ODBC Administrator . 1. Open the ODBC Administrator. 2. Select the `Tracing' tab. ODBC Administrator Tracing Dialog 3. Select the `Enable Tracing' check box. 4. Enter the location where you want to save the Tracing log. If you want to append information to an existing log file, click the `Choose...' button.  File: manual.info, Node: connector-odbc-configuration-trace-unix, Next: connector-odbc-configuration-trace-log, Prev: connector-odbc-configuration-trace-macosx, Up: connector-odbc-configuration-trace 21.1.4.14 Enabling ODBC Tracing on Unix ....................................... To enable the trace option on Mac OS X 10.2 (or earlier) or Unix you must add the `trace' option to the ODBC configuration: 1. On Unix, you need to explicitly set the `Trace' option in the `ODBC.INI' file. Set the tracing `ON' or `OFF' by using `TraceFile' and `Trace' parameters in `odbc.ini' as shown below: TraceFile = /tmp/odbc.trace Trace = 1 `TraceFile' specifies the name and full path of the trace file and `Trace' is set to `ON' or `OFF'. You can also use `1' or `YES' for `ON' and `0' or `NO' for `OFF'. If you are using `ODBCConfig' from `unixODBC', then follow the instructions for tracing `unixODBC' calls at HOWTO-ODBCConfig (http://www.unixodbc.org/config.html).  File: manual.info, Node: connector-odbc-configuration-trace-log, Prev: connector-odbc-configuration-trace-unix, Up: connector-odbc-configuration-trace 21.1.4.15 Enabling a Connector/ODBC Log ....................................... To generate a Connector/ODBC log, do the following: 1. Within Windows, enable the `Trace Connector/ODBC' option flag in the Connector/ODBC connect/configure screen. The log is written to file `C:\myodbc.log'. If the trace option is not remembered when you are going back to the above screen, it means that you are not using the `myodbcd.dll' driver, see *Note connector-odbc-configuration-dsn-windows-problems::. On Mac OS X, Unix, or if you are using DSN-Less connection, then you need to supply `OPTION=4' in the connection string or set the corresponding keyword/value pair in the DSN. 2. Start your application and try to get it to fail. Then check the Connector/ODBC trace file to find out what could be wrong. If you need help determining what is wrong, see *Note connector-odbc-support-community::.  File: manual.info, Node: connector-odbc-examples, Next: connector-odbc-reference, Prev: connector-odbc-configuration, Up: connector-odbc 21.1.5 Connector/ODBC Examples ------------------------------ * Menu: * connector-odbc-examples-overview:: Basic Connector/ODBC Application Steps * connector-odbc-examples-walkthrough:: Step-by-step Guide to Connecting to a MySQL Database through Connector/ODBC * connector-odbc-examples-tools:: Connector/ODBC and Third-Party ODBC Tools * connector-odbc-examples-tools-with-access:: Using Connector/ODBC with Microsoft Access * connector-odbc-examples-tools-with-wordexcel:: Using Connector/ODBC with Microsoft Word or Excel * connector-odbc-examples-tools-with-crystalreports:: Using Connector/ODBC with Crystal Reports * connector-odbc-examples-programming:: Connector/ODBC Programming Once you have configured a DSN to provide access to a database, how you access and use that connection is dependent on the application or programming language. As ODBC is a standardized interface, any application or language that supports ODBC can use the DSN and connect to the configured database.  File: manual.info, Node: connector-odbc-examples-overview, Next: connector-odbc-examples-walkthrough, Prev: connector-odbc-examples, Up: connector-odbc-examples 21.1.5.1 Basic Connector/ODBC Application Steps ............................................... Interacting with a MySQL server from an applications using the Connector/ODBC typically involves the following operations: * Configure the Connector/ODBC DSN * Connect to MySQL server * Initialization operations * Execute SQL statements * Retrieve results * Perform Transactions * Disconnect from the server Most applications use some variation of these steps. The basic application steps are shown in the following diagram: Connector/ODBC Programming Flowchart  File: manual.info, Node: connector-odbc-examples-walkthrough, Next: connector-odbc-examples-tools, Prev: connector-odbc-examples-overview, Up: connector-odbc-examples 21.1.5.2 Step-by-step Guide to Connecting to a MySQL Database through Connector/ODBC .................................................................................... A typical installation situation where you would install Connector/ODBC is when you want to access a database on a Linux or Unix host from a Windows machine. As an example of the process required to set up access between two machines, the steps below take you through the basic steps. These instructions assume that you want to connect to system ALPHA from system BETA with a user name and password of `myuser' and `mypassword'. On system ALPHA (the MySQL server) follow these steps: 1. Start the MySQL server. 2. Use *Note `GRANT': grant. to set up an account with a user name of `myuser' that can connect from system BETA using a password of `myuser' to the database `test': GRANT ALL ON test.* to 'myuser'@'BETA' IDENTIFIED BY 'mypassword'; For more information about MySQL privileges, refer to *Note user-account-management::. On system BETA (the Connector/ODBC client), follow these steps: 1. Configure a Connector/ODBC DSN using parameters that match the server, database and authentication information that you have just configured on system ALPHA. Parameter Value Comment DSN remote_test A name to identify the connection. SERVER ALPHA The address of the remote server. DATABASE test The name of the default database. USER myuser The user name configured for access to this database. PASSWORD mypassword The password for `myuser'. 2. Using an ODBC-capable application, such as Microsoft Office, connect to the MySQL server using the DSN you have just created. If the connection fails, use tracing to examine the connection process. See *Note connector-odbc-configuration-trace::, for more information.  File: manual.info, Node: connector-odbc-examples-tools, Next: connector-odbc-examples-tools-with-access, Prev: connector-odbc-examples-walkthrough, Up: connector-odbc-examples 21.1.5.3 Connector/ODBC and Third-Party ODBC Tools .................................................. Once you have configured your Connector/ODBC DSN, you can access your MySQL database through any application that supports the ODBC interface, including programming languages and third-party applications. This section contains guides and help on using Connector/ODBC with various ODBC-compatible tools and applications, including Microsoft Word, Microsoft Excel and Adobe/Macromedia ColdFusion. Connector/ODBC has been tested with the following applications. Publisher Application Notes Adobe ColdFusion Formerly Macromedia ColdFusion Borland C++ Builder Builder 4 Delphi Business Objects Crystal Reports Claris Filemaker Pro Corel Paradox Computer Visual Objects Also known as CAVO Associates AllFusion ERwin Data Modeler Gupta Team Developer Previously known as Centura Team Developer; Gupta SQL/Windows Gensym G2-ODBC Bridge Inline iHTML Lotus Notes Versions 4.5 and 4.6 Microsoft Access Excel Visio Enterprise Visual C++ Visual Basic ODBC.NET Using C#, Visual Basic, C++ FoxPro Visual Interdev OpenOffice.org OpenOffice.org Perl DBD::ODBC Pervasive Software DataJunction Sambar Sambar Server Technologies SPSS SPSS SoftVelocity Clarion SQLExpress SQLExpress for Xbase++ Sun StarOffice SunSystems Vision Sybase PowerBuilder PowerDesigner theKompany.com Data Architect If you know of any other applications that work with Connector/ODBC, please send mail to about them.  File: manual.info, Node: connector-odbc-examples-tools-with-access, Next: connector-odbc-examples-tools-with-wordexcel, Prev: connector-odbc-examples-tools, Up: connector-odbc-examples 21.1.5.4 Using Connector/ODBC with Microsoft Access ................................................... * Menu: * connector-odbc-examples-tools-with-access-export:: Exporting Access Data to MySQL * connector-odbc-examples-tools-with-access-import:: Importing MySQL Data to Access * connector-odbc-examples-tools-with-access-linked-tables:: Using Microsoft Access as a Front-end to MySQL You can use MySQL database with Microsoft Access using Connector/ODBC. The MySQL database can be used as an import source, an export source, or as a linked table for direct use within an Access application, so you can use Access as the front-end interface to a MySQL database.  File: manual.info, Node: connector-odbc-examples-tools-with-access-export, Next: connector-odbc-examples-tools-with-access-import, Prev: connector-odbc-examples-tools-with-access, Up: connector-odbc-examples-tools-with-access 21.1.5.5 Exporting Access Data to MySQL ....................................... To export a table of data from an Access database to MySQL, follow these instructions: 1. When you open an Access database or an Access project, a Database window appears. It displays shortcuts for creating new database objects and opening existing objects. Access Database 2. Click the name of the `table' or `query' you want to export, and then in the `File' menu, select `Export'. 3. In the `Export Object Type OBJECT NAME To' dialog box, in the `Save As Type' box, select `ODBC Databases ()' as shown here: Selecting an ODBC Database 4. In the `Export' dialog box, enter a name for the file (or use the suggested name), and then select `OK'. 5. The Select Data Source dialog box is displayed; it lists the defined data sources for any ODBC drivers installed on your computer. Click either the File Data Source or Machine Data Source tab, and then double-click the Connector/ODBC or Connector/ODBC 3.51 data source that you want to export to. To define a new data source for Connector/ODBC, please *Note connector-odbc-configuration-dsn-windows::. *Note*: Ensure that the information that you are exporting to the MySQL table is valid for the corresponding MySQL data types. Values that are outside of the supported range of the MySQL data type but valid within Access may trigger an `overflow' error during the export. Microsoft Access connects to the MySQL Server through this data source and exports new tables and or data.  File: manual.info, Node: connector-odbc-examples-tools-with-access-import, Next: connector-odbc-examples-tools-with-access-linked-tables, Prev: connector-odbc-examples-tools-with-access-export, Up: connector-odbc-examples-tools-with-access 21.1.5.6 Importing MySQL Data to Access ....................................... To import a table or tables from MySQL to Access, follow these instructions: 1. Open a database, or switch to the Database window for the open database. 2. To import tables, on the `File' menu, point to `Get External Data', and then click `Import'. 3. In the `Import' dialog box, in the Files Of Type box, select `ODBC Databases ()'. The Select Data Source dialog box lists the defined data sources `The Select Data Source' dialog box is displayed; it lists the defined data source names. 4. If the ODBC data source that you selected requires you to log on, enter your login ID and password (additional information might also be required), and then click `OK'. 5. Microsoft Access connects to the MySQL server through `ODBC data source ' and displays the list of tables that you can `import'. 6. Click each table that you want to `import', and then click `OK'.  File: manual.info, Node: connector-odbc-examples-tools-with-access-linked-tables, Prev: connector-odbc-examples-tools-with-access-import, Up: connector-odbc-examples-tools-with-access 21.1.5.7 Using Microsoft Access as a Front-end to MySQL ....................................................... You can use Microsoft Access as a front end to a MySQL database by linking tables within your Microsoft Access database to tables that exist within your MySQL database. When a query is requested on a table within Access, ODBC is used to execute the queries on the MySQL database instead. *To create a linked table*: 1. Open the Access database that you want to link to MySQL. 2. From the `File', choose `Get External Data->Link Tables'. Linking Microsoft Access tables to MySQL tables 3. From the browser, choose `ODBC Databases ()' from the `Files of type' pop-up. 4. In the `Select Data Source' window, choose an existing DSN, either from a `File Data Source' or `Machine Data Source'.You can also create a new DSN using the `New...' button. For more information on creating a DSN see *Note connector-odbc-configuration-dsn-windows::. Linking Microsoft Access tables to MySQL tables, choosing a DSN 5. In the `Link Tables' dialog, select one or more tables from the MySQL database. A link will be created to each table that you select from this list. Linking Microsoft Access tables to MySQL tables, table selection 6. If Microsoft Access is unable to determine the unique record identifier for a table automatically then it may ask you to confirm the column, or combination of columns, to be used to uniquely identify each row from the source table. Select the columns you want to use and click `OK'. Linking Microsoft Access tables to MySQL tables, choosing unique record identifier Once the process has been completed, you can now build interfaces and queries to the linked tables just as you would for any Access database. Use the following procedure to view or to refresh links when the structure or location of a linked table has changed. The Linked Table Manager lists the paths to all currently linked tables. *To view or refresh links*: 1. Open the database that contains links to MySQL tables. 2. On the `Tools' menu, point to `Add-ins' (`Database Utilities' in Access 2000 or newer), and then click `Linked Table Manager'. 3. Select the check box for the tables whose links you want to refresh. 4. Click OK to refresh the links. Microsoft Access confirms a successful refresh or, if the table wasn't found, displays the `Select New Location of'
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dialog box in which you can specify its the table's new location. If several selected tables have moved to the new location that you specify, the Linked Table Manager searches that location for all selected tables, and updates all links in one step. *To change the path for a set of linked tables*: 1. Open the database that contains links to tables. 2. On the `Tools' menu, point to `Add-ins' (`Database Utilities' in Access 2000 or newer), and then click `Linked Table Manager'. 3. Select the `Always Prompt For A New Location' check box. 4. Select the check box for the tables whose links you want to change, and then click `OK'. 5. In the `Select New Location of'
dialog box, specify the new location, click `Open', and then click `OK'.  File: manual.info, Node: connector-odbc-examples-tools-with-wordexcel, Next: connector-odbc-examples-tools-with-crystalreports, Prev: connector-odbc-examples-tools-with-access, Up: connector-odbc-examples 21.1.5.8 Using Connector/ODBC with Microsoft Word or Excel .......................................................... You can use Microsoft Word and Microsoft Excel to access information from a MySQL database using Connector/ODBC. Within Microsoft Word, this facility is most useful when importing data for mailmerge, or for tables and data to be included in reports. Within Microsoft Excel, you can execute queries on your MySQL server and import the data directly into an Excel Worksheet, presenting the data as a series of rows and columns. With both applications, data is accessed and imported into the application using Microsoft Query , which enables you to execute a query though an ODBC source. You use Microsoft Query to build the SQL statement to be executed, selecting the tables, fields, selection criteria and sort order. For example, to insert information from a table in the World test database into an Excel spreadsheet, using the DSN samples shown in *Note connector-odbc-configuration::: 1. Create a new Worksheet. 2. From the `Data' menu, choose `Import External Data', and then select `New Database Query'. 3. Microsoft Query will start. First, you need to choose the data source, by selecting an existing Data Source Name. Microsoft Query, Choose Data Source 4. Within the `Query Wizard', you must choose the columns that you want to import. The list of tables available to the user configured through the DSN is shown on the left, the columns that will be added to your query are shown on the right. The columns you choose are equivalent to those in the first section of a *Note `SELECT': select. query. Click `Next' to continue. Microsoft Query, Choose Columns 5. You can filter rows from the query (the equivalent of a `WHERE' clause) using the `Filter Data' dialog. Click `Next' to continue. Microsoft Query, Filter Data 6. Select an (optional) sort order for the data. This is equivalent to using a `ORDER BY' clause in your SQL query. You can select up to three fields for sorting the information returned by the query. Click `Next' to continue. Microsoft Query, Sort Order 7. Select the destination for your query. You can select to return the data Microsoft Excel, where you can choose a worksheet and cell where the data will be inserted; you can continue to view the query and results within Microsoft Query, where you can edit the SQL query and further filter and sort the information returned; or you can create an OLAP Cube from the query, which can then be used directly within Microsoft Excel. Click `Finish'. Microsoft Query, Selecting a destination The same process can be used to import data into a Word document, where the data will be inserted as a table. This can be used for mail merge purposes (where the field data is read from a Word table), or where you want to include data and reports within a report or other document.  File: manual.info, Node: connector-odbc-examples-tools-with-crystalreports, Next: connector-odbc-examples-programming, Prev: connector-odbc-examples-tools-with-wordexcel, Up: connector-odbc-examples 21.1.5.9 Using Connector/ODBC with Crystal Reports .................................................. Crystal Reports can use an ODBC DSN to connect to a database from which you to extract data and information for reporting purposes. *Note*: There is a known issue with certain versions of Crystal Reports where the application is unable to open and browse tables and fields through an ODBC connection. Before using Crystal Reports with MySQL, please ensure that you have update to the latest version, including any outstanding service packs and hotfixes. For more information on this issue, see the Business) Objects Knowledgebase (http://support.crystaldecisions.com/library/kbase/new_articles/c2013269.asp) for more information. For example, to create a simple crosstab report within Crystal Reports XI, you should follow these steps: 1. Create a DSN using the `Data Sources (ODBC)' tool. You can either specify a complete database, including user name and password, or you can build a basic DSN and use Crystal Reports to set the user name and password. For the purposes of this example, a DSN that provides a connection to an instance of the MySQL Sakila sample database has been created. 2. Open Crystal Reports and create a new project, or an open an existing reporting project into which you want to insert data from your MySQL data source. 3. Start the Cross-Tab Report Wizard, either by clicking the option on the Start Page. Expand the `Create New Connection' folder, then expand the `ODBC (RDO)' folder to obtain a list of ODBC data sources. You will be asked to select a data source. Selecting an Data Source in Crystal Reports 4. When you first expand the `ODBC (RDO)' folder you will be presented the Data Source Selection screen. From here you can select either a pre-configured DSN, open a file-based DSN or enter and manual connection string. For this example, the `Sakila' DSN will be used. If the DSN contains a user name/password combination, or you want to use different authentication credentials, click `Next' to enter the user name and password that you want to use. Otherwise, click `Finish' to continue the data source selection wizard. Selecting an ODBC Data Source in Crystal Reports 5. You will be returned the Cross-Tab Report Creation Wizard. You now need to select the database and tables that you want to include in your report. For our example, we will expand the selected Sakila database. Click the `city' table and use the `>' button to add the table to the report. Then repeat the action with the `country' table. Alternatively you can select multiple tables and add them to the report. Finally, you can select the parent `Sakila' resource and add of the tables to the report. Once you have selected the tables you want to include, click `Next' to continue. Selecting an tables in Crystal Reports 6. Crystal Reports will now read the table definitions and automatically identify the links between the tables. The identification of links between tables enables Crystal Reports to automatically lookup and summarize information based on all the tables in the database according to your query. If Crystal Reports is unable to perform the linking itself, you can manually create the links between fields in the tables you have selected. Click `Next' to continue the process. Table links/structure in Crystal Reports 7. You can now select the columns and rows that you wish to include within the Cross-Tab report. Drag and drop or use the `>' buttons to add fields to each area of the report. In the example shown, we will report on cities, organized by country, incorporating a count of the number of cities within each country. If you want to browse the data, select a field and click the `Browse Data...' button. Click `Next' to create a graph of the results. Since we are not creating a graph from this data, click `Finish' to generate the report. Cross-tab definition in Crystal Reports 8. The finished report will be shown, a sample of the output from the Sakila sample database is shown below. Cross-tab final report in Crystal Reports Once the ODBC connection has been opened within Crystal Reports, you can browse and add any fields within the available tables into your reports.  File: manual.info, Node: connector-odbc-examples-programming, Prev: connector-odbc-examples-tools-with-crystalreports, Up: connector-odbc-examples 21.1.5.10 Connector/ODBC Programming .................................... * Menu: * connector-odbc-examples-programming-vb:: Using Connector/ODBC with Visual Basic Using ADO, DAO and RDO * connector-odbc-examples-programming-net:: Using Connector/ODBC with .NET With a suitable ODBC Manager and the Connector/ODBC driver installed, any programming language or environment that can support ODBC should be able to connect to a MySQL database through Connector/ODBC. This includes, but is certainly not limited to, Microsoft support languages (including Visual Basic, C# and interfaces such as ODBC.NET), Perl (through the DBI module, and the DBD::ODBC driver).  File: manual.info, Node: connector-odbc-examples-programming-vb, Next: connector-odbc-examples-programming-net, Prev: connector-odbc-examples-programming, Up: connector-odbc-examples-programming 21.1.5.11 Using Connector/ODBC with Visual Basic Using ADO, DAO and RDO ....................................................................... * Menu: * connector-odbc-examples-programming-vb-ado:: ADO: `rs.addNew', `rs.delete', and `rs.update' * connector-odbc-examples-programming-vb-dao:: DAO: `rs.addNew', `rs.update', and Scrolling * connector-odbc-examples-programming-vb-rdo:: RDO: `rs.addNew' and `rs.update' This section contains simple examples of the use of MySQL ODBC 3.51 Driver with ADO, DAO and RDO.  File: manual.info, Node: connector-odbc-examples-programming-vb-ado, Next: connector-odbc-examples-programming-vb-dao, Prev: connector-odbc-examples-programming-vb, Up: connector-odbc-examples-programming-vb 21.1.5.12 ADO: `rs.addNew', `rs.delete', and `rs.update' ........................................................ The following ADO (ActiveX Data Objects) example creates a table `my_ado' and demonstrates the use of `rs.addNew', `rs.delete', and `rs.update'. Private Sub myodbc_ado_Click() Dim conn As ADODB.Connection Dim rs As ADODB.Recordset Dim fld As ADODB.Field Dim sql As String 'connect to MySQL server using MySQL ODBC 3.51 Driver Set conn = New ADODB.Connection conn.ConnectionString = "DRIVER={MySQL ODBC 3.51 Driver};"_ & "SERVER=localhost;"_ & " DATABASE=test;"_ & "UID=venu;PWD=venu; OPTION=3" conn.Open 'create table conn.Execute "DROP TABLE IF EXISTS my_ado" conn.Execute "CREATE TABLE my_ado(id int not null primary key, name varchar(20)," _ & "txt text, dt date, tm time, ts timestamp)" 'direct insert conn.Execute "INSERT INTO my_ado(id,name,txt) values(1,100,'venu')" conn.Execute "INSERT INTO my_ado(id,name,txt) values(2,200,'MySQL')" conn.Execute "INSERT INTO my_ado(id,name,txt) values(3,300,'Delete')" Set rs = New ADODB.Recordset rs.CursorLocation = adUseServer 'fetch the initial table .. rs.Open "SELECT * FROM my_ado", conn Debug.Print rs.RecordCount rs.MoveFirst Debug.Print String(50, "-") & "Initial my_ado Result Set " & String(50, "-") For Each fld In rs.Fields Debug.Print fld.Name, Next Debug.Print Do Until rs.EOF For Each fld In rs.Fields Debug.Print fld.Value, Next rs.MoveNext Debug.Print Loop rs.Close 'rs insert rs.Open "select * from my_ado", conn, adOpenDynamic, adLockOptimistic rs.AddNew rs!Name = "Monty" rs!txt = "Insert row" rs.Update rs.Close 'rs update rs.Open "SELECT * FROM my_ado" rs!Name = "update" rs!txt = "updated-row" rs.Update rs.Close 'rs update second time.. rs.Open "SELECT * FROM my_ado" rs!Name = "update" rs!txt = "updated-second-time" rs.Update rs.Close 'rs delete rs.Open "SELECT * FROM my_ado" rs.MoveNext rs.MoveNext rs.Delete rs.Close 'fetch the updated table .. rs.Open "SELECT * FROM my_ado", conn Debug.Print rs.RecordCount rs.MoveFirst Debug.Print String(50, "-") & "Updated my_ado Result Set " & String(50, "-") For Each fld In rs.Fields Debug.Print fld.Name, Next Debug.Print Do Until rs.EOF For Each fld In rs.Fields Debug.Print fld.Value, Next rs.MoveNext Debug.Print Loop rs.Close conn.Close End Sub  File: manual.info, Node: connector-odbc-examples-programming-vb-dao, Next: connector-odbc-examples-programming-vb-rdo, Prev: connector-odbc-examples-programming-vb-ado, Up: connector-odbc-examples-programming-vb 21.1.5.13 DAO: `rs.addNew', `rs.update', and Scrolling ...................................................... The following DAO (Data Access Objects) example creates a table `my_dao' and demonstrates the use of `rs.addNew', `rs.update', and result set scrolling. Private Sub myodbc_dao_Click() Dim ws As Workspace Dim conn As Connection Dim queryDef As queryDef Dim str As String 'connect to MySQL using MySQL ODBC 3.51 Driver Set ws = DBEngine.CreateWorkspace("", "venu", "venu", dbUseODBC) str = "odbc;DRIVER={MySQL ODBC 3.51 Driver};"_ & "SERVER=localhost;"_ & " DATABASE=test;"_ & "UID=venu;PWD=venu; OPTION=3" Set conn = ws.OpenConnection("test", dbDriverNoPrompt, False, str) 'Create table my_dao Set queryDef = conn.CreateQueryDef("", "drop table if exists my_dao") queryDef.Execute Set queryDef = conn.CreateQueryDef("", "create table my_dao(Id INT AUTO_INCREMENT PRIMARY KEY, " _ & "Ts TIMESTAMP(14) NOT NULL, Name varchar(20), Id2 INT)") queryDef.Execute 'Insert new records using rs.addNew Set rs = conn.OpenRecordset("my_dao") Dim i As Integer For i = 10 To 15 rs.AddNew rs!Name = "insert record" & i rs!Id2 = i rs.Update Next i rs.Close 'rs update.. Set rs = conn.OpenRecordset("my_dao") rs.Edit rs!Name = "updated-string" rs.Update rs.Close 'fetch the table back... Set rs = conn.OpenRecordset("my_dao", dbOpenDynamic) str = "Results:" rs.MoveFirst While Not rs.EOF str = " " & rs!Id & " , " & rs!Name & ", " & rs!Ts & ", " & rs!Id2 Debug.Print "DATA:" & str rs.MoveNext Wend 'rs Scrolling rs.MoveFirst str = " FIRST ROW: " & rs!Id & " , " & rs!Name & ", " & rs!Ts & ", " & rs!Id2 Debug.Print str rs.MoveLast str = " LAST ROW: " & rs!Id & " , " & rs!Name & ", " & rs!Ts & ", " & rs!Id2 Debug.Print str rs.MovePrevious str = " LAST-1 ROW: " & rs!Id & " , " & rs!Name & ", " & rs!Ts & ", " & rs!Id2 Debug.Print str 'free all resources rs.Close queryDef.Close conn.Close ws.Close End Sub  File: manual.info, Node: connector-odbc-examples-programming-vb-rdo, Prev: connector-odbc-examples-programming-vb-dao, Up: connector-odbc-examples-programming-vb 21.1.5.14 RDO: `rs.addNew' and `rs.update' .......................................... The following RDO (Remote Data Objects) example creates a table `my_rdo' and demonstrates the use of `rs.addNew' and `rs.update'. Dim rs As rdoResultset Dim cn As New rdoConnection Dim cl As rdoColumn Dim SQL As String 'cn.Connect = "DSN=test;" cn.Connect = "DRIVER={MySQL ODBC 3.51 Driver};"_ & "SERVER=localhost;"_ & " DATABASE=test;"_ & "UID=venu;PWD=venu; OPTION=3" cn.CursorDriver = rdUseOdbc cn.EstablishConnection rdDriverPrompt 'drop table my_rdo SQL = "drop table if exists my_rdo" cn.Execute SQL, rdExecDirect 'create table my_rdo SQL = "create table my_rdo(id int, name varchar(20))" cn.Execute SQL, rdExecDirect 'insert - direct SQL = "insert into my_rdo values (100,'venu')" cn.Execute SQL, rdExecDirect SQL = "insert into my_rdo values (200,'MySQL')" cn.Execute SQL, rdExecDirect 'rs insert SQL = "select * from my_rdo" Set rs = cn.OpenResultset(SQL, rdOpenStatic, rdConcurRowVer, rdExecDirect) rs.AddNew rs!id = 300 rs!Name = "Insert1" rs.Update rs.Close 'rs insert SQL = "select * from my_rdo" Set rs = cn.OpenResultset(SQL, rdOpenStatic, rdConcurRowVer, rdExecDirect) rs.AddNew rs!id = 400 rs!Name = "Insert 2" rs.Update rs.Close 'rs update SQL = "select * from my_rdo" Set rs = cn.OpenResultset(SQL, rdOpenStatic, rdConcurRowVer, rdExecDirect) rs.Edit rs!id = 999 rs!Name = "updated" rs.Update rs.Close 'fetch back... SQL = "select * from my_rdo" Set rs = cn.OpenResultset(SQL, rdOpenStatic, rdConcurRowVer, rdExecDirect) Do Until rs.EOF For Each cl In rs.rdoColumns Debug.Print cl.Value, Next rs.MoveNext Debug.Print Loop Debug.Print "Row count="; rs.RowCount 'close rs.Close cn.Close End Sub  File: manual.info, Node: connector-odbc-examples-programming-net, Prev: connector-odbc-examples-programming-vb, Up: connector-odbc-examples-programming 21.1.5.15 Using Connector/ODBC with .NET ........................................ * Menu: * connector-odbc-examples-programming-net-csharp:: Using Connector/ODBC with ODBC.NET and C# (C sharp) * connector-odbc-examples-programming-net-vb:: Using Connector/ODBC with ODBC.NET and Visual Basic This section contains simple examples that demonstrate the use of Connector/ODBC drivers with ODBC.NET.  File: manual.info, Node: connector-odbc-examples-programming-net-csharp, Next: connector-odbc-examples-programming-net-vb, Prev: connector-odbc-examples-programming-net, Up: connector-odbc-examples-programming-net 21.1.5.16 Using Connector/ODBC with ODBC.NET and C# (C sharp) ............................................................. The following sample creates a table `my_odbc_net' and demonstrates its use in C#. /** * @sample : mycon.cs * @purpose : Demo sample for ODBC.NET using Connector/ODBC * @author : Venu, * * (C) Copyright MySQL AB, 1995-2006 * **/ /* build command * * csc /t:exe * /out:mycon.exe mycon.cs * /r:Microsoft.Data.Odbc.dll */ using Console = System.Console; using Microsoft.Data.Odbc; namespace myodbc3 { class mycon { static void Main(string[] args) { try { //Connection string for Connector/ODBC 3.51 string MyConString = "DRIVER={MySQL ODBC 3.51 Driver};" + "SERVER=localhost;" + "DATABASE=test;" + "UID=venu;" + "PASSWORD=venu;" + "OPTION=3"; //Connect to MySQL using Connector/ODBC OdbcConnection MyConnection = new OdbcConnection(MyConString); MyConnection.Open(); Console.WriteLine("\n !!! success, connected successfully !!!\n"); //Display connection information Console.WriteLine("Connection Information:"); Console.WriteLine("\tConnection String:" + MyConnection.ConnectionString); Console.WriteLine("\tConnection Timeout:" + MyConnection.ConnectionTimeout); Console.WriteLine("\tDatabase:" + MyConnection.Database); Console.WriteLine("\tDataSource:" + MyConnection.DataSource); Console.WriteLine("\tDriver:" + MyConnection.Driver); Console.WriteLine("\tServerVersion:" + MyConnection.ServerVersion); //Create a sample table OdbcCommand MyCommand = new OdbcCommand("DROP TABLE IF EXISTS my_odbc_net", MyConnection); MyCommand.ExecuteNonQuery(); MyCommand.CommandText = "CREATE TABLE my_odbc_net(id int, name varchar(20), idb bigint)"; MyCommand.ExecuteNonQuery(); //Insert MyCommand.CommandText = "INSERT INTO my_odbc_net VALUES(10,'venu', 300)"; Console.WriteLine("INSERT, Total rows affected:" + MyCommand.ExecuteNonQuery());; //Insert MyCommand.CommandText = "INSERT INTO my_odbc_net VALUES(20,'mysql',400)"; Console.WriteLine("INSERT, Total rows affected:" + MyCommand.ExecuteNonQuery()); //Insert MyCommand.CommandText = "INSERT INTO my_odbc_net VALUES(20,'mysql',500)"; Console.WriteLine("INSERT, Total rows affected:" + MyCommand.ExecuteNonQuery()); //Update MyCommand.CommandText = "UPDATE my_odbc_net SET id=999 WHERE id=20"; Console.WriteLine("Update, Total rows affected:" + MyCommand.ExecuteNonQuery()); //COUNT(*) MyCommand.CommandText = "SELECT COUNT(*) as TRows FROM my_odbc_net"; Console.WriteLine("Total Rows:" + MyCommand.ExecuteScalar()); //Fetch MyCommand.CommandText = "SELECT * FROM my_odbc_net"; OdbcDataReader MyDataReader; MyDataReader = MyCommand.ExecuteReader(); while (MyDataReader.Read()) { if(string.Compare(MyConnection.Driver,"myodbc3.dll") == 0) { //Supported only by Connector/ODBC 3.51 Console.WriteLine("Data:" + MyDataReader.GetInt32(0) + " " + MyDataReader.GetString(1) + " " + MyDataReader.GetInt64(2)); } else { //BIGINTs not supported by Connector/ODBC Console.WriteLine("Data:" + MyDataReader.GetInt32(0) + " " + MyDataReader.GetString(1) + " " + MyDataReader.GetInt32(2)); } } //Close all resources MyDataReader.Close(); MyConnection.Close(); } catch (OdbcException MyOdbcException) //Catch any ODBC exception .. { for (int i=0; i < MyOdbcException.Errors.Count; i++) { Console.Write("ERROR #" + i + "\n" + "Message: " + MyOdbcException.Errors[i].Message + "\n" + "Native: " + MyOdbcException.Errors[i].NativeError.ToString() + "\n" + "Source: " + MyOdbcException.Errors[i].Source + "\n" + "SQL: " + MyOdbcException.Errors[i].SQLState + "\n"); } } } } }  File: manual.info, Node: connector-odbc-examples-programming-net-vb, Prev: connector-odbc-examples-programming-net-csharp, Up: connector-odbc-examples-programming-net 21.1.5.17 Using Connector/ODBC with ODBC.NET and Visual Basic ............................................................. The following sample creates a table `my_vb_net' and demonstrates the use in VB. ' @sample : myvb.vb ' @purpose : Demo sample for ODBC.NET using Connector/ODBC ' @author : Venu, ' ' (C) Copyright MySQL AB, 1995-2006 ' ' ' ' build command ' ' vbc /target:exe ' /out:myvb.exe ' /r:Microsoft.Data.Odbc.dll ' /r:System.dll ' /r:System.Data.dll ' Imports Microsoft.Data.Odbc Imports System Module myvb Sub Main() Try 'Connector/ODBC 3.51 connection string Dim MyConString As String = "DRIVER={MySQL ODBC 3.51 Driver};" & _ "SERVER=localhost;" & _ "DATABASE=test;" & _ "UID=venu;" & _ "PASSWORD=venu;" & _ "OPTION=3;" 'Connection Dim MyConnection As New OdbcConnection(MyConString) MyConnection.Open() Console.WriteLine("Connection State::" & MyConnection.State.ToString) 'Drop Console.WriteLine("Dropping table") Dim MyCommand As New OdbcCommand() MyCommand.Connection = MyConnection MyCommand.CommandText = "DROP TABLE IF EXISTS my_vb_net" MyCommand.ExecuteNonQuery() 'Create Console.WriteLine("Creating....") MyCommand.CommandText = "CREATE TABLE my_vb_net(id int, name varchar(30))" MyCommand.ExecuteNonQuery() 'Insert MyCommand.CommandText = "INSERT INTO my_vb_net VALUES(10,'venu')" Console.WriteLine("INSERT, Total rows affected:" & _ MyCommand.ExecuteNonQuery()) 'Insert MyCommand.CommandText = "INSERT INTO my_vb_net VALUES(20,'mysql')" Console.WriteLine("INSERT, Total rows affected:" & _ MyCommand.ExecuteNonQuery()) 'Insert MyCommand.CommandText = "INSERT INTO my_vb_net VALUES(20,'mysql')" Console.WriteLine("INSERT, Total rows affected:" & _ MyCommand.ExecuteNonQuery()) 'Insert MyCommand.CommandText = "INSERT INTO my_vb_net(id) VALUES(30)" Console.WriteLine("INSERT, Total rows affected:" & _ MyCommand.ExecuteNonQuery()) 'Update MyCommand.CommandText = "UPDATE my_vb_net SET id=999 WHERE id=20" Console.WriteLine("Update, Total rows affected:" & _ MyCommand.ExecuteNonQuery()) 'COUNT(*) MyCommand.CommandText = "SELECT COUNT(*) as TRows FROM my_vb_net" Console.WriteLine("Total Rows:" & MyCommand.ExecuteScalar()) 'Select Console.WriteLine("Select * FROM my_vb_net") MyCommand.CommandText = "SELECT * FROM my_vb_net" Dim MyDataReader As OdbcDataReader MyDataReader = MyCommand.ExecuteReader While MyDataReader.Read If MyDataReader("name") Is DBNull.Value Then Console.WriteLine("id = " & _ CStr(MyDataReader("id")) & " name = " & _ "NULL") Else Console.WriteLine("id = " & _ CStr(MyDataReader("id")) & " name = " & _ CStr(MyDataReader("name"))) End If End While 'Catch ODBC Exception Catch MyOdbcException As OdbcException Dim i As Integer Console.WriteLine(MyOdbcException.ToString) 'Catch program exception Catch MyException As Exception Console.WriteLine(MyException.ToString) End Try End Sub  File: manual.info, Node: connector-odbc-reference, Next: connector-odbc-usagenotes, Prev: connector-odbc-examples, Up: connector-odbc 21.1.6 Connector/ODBC Reference ------------------------------- * Menu: * connector-odbc-reference-api:: Connector/ODBC API Reference * connector-odbc-reference-datatypes:: Connector/ODBC Data Types * connector-odbc-reference-errorcodes:: Connector/ODBC Error Codes This section provides reference material for the Connector/ODBC API, showing supported functions and methods, supported MySQL column types and the corresponding native type in Connector/ODBC, and the error codes returned by Connector/ODBC when a fault occurs.  File: manual.info, Node: connector-odbc-reference-api, Next: connector-odbc-reference-datatypes, Prev: connector-odbc-reference, Up: connector-odbc-reference 21.1.6.1 Connector/ODBC API Reference ..................................... This section summarizes ODBC routines, categorized by functionality. For the complete ODBC API reference, please refer to the ODBC Programmer's Reference at `http://msdn.microsoft.com/en-us/library/ms714177.aspx'. An application can call `SQLGetInfo' function to obtain conformance information about Connector/ODBC. To obtain information about support for a specific function in the driver, an application can call `SQLGetFunctions'. *Note*: For backward compatibility, the Connector/ODBC 3.51 driver supports all deprecated functions. The following tables list Connector/ODBC API calls grouped by task: *Connecting to a data source* Function name C/ODBC Standard Purpose 3.51 `SQLAllocHandle' Yes ISO 92 Obtains an environment, connection, statement, or descriptor handle. `SQLConnect' Yes ISO 92 Connects to a specific driver by data source name, user ID, and password. `SQLDriverConnect' Yes ODBC Connects to a specific driver by connection string or requests that the Driver Manager and driver display connection dialog boxes for the user. `SQLAllocEnv' Yes DeprecatedObtains an environment handle allocated from driver. `SQLAllocConnect' Yes DeprecatedObtains a connection handle *Obtaining information about a driver and data source* Function name C/ODBC Standard Purpose 3.51 `SQLDataSources' No ISO 92 Returns the list of available data sources, handled by the Driver Manager `SQLDrivers' No ODBC Returns the list of installed drivers and their attributes, handles by Driver Manager `SQLGetInfo' Yes ISO 92 Returns information about a specific driver and data source. `SQLGetFunctions' Yes ISO 92 Returns supported driver functions. `SQLGetTypeInfo' Yes ISO 92 Returns information about supported data types. *Setting and retrieving driver attributes* Function name C/ODBC Standard Purpose 3.51 `SQLSetConnectAttr' Yes ISO 92 Sets a connection attribute. `SQLGetConnectAttr' Yes ISO 92 Returns the value of a connection attribute. `SQLSetConnectOption'Yes DeprecatedSets a connection option `SQLGetConnectOption'Yes DeprecatedReturns the value of a connection option `SQLSetEnvAttr' Yes ISO 92 Sets an environment attribute. `SQLGetEnvAttr' Yes ISO 92 Returns the value of an environment attribute. `SQLSetStmtAttr' Yes ISO 92 Sets a statement attribute. `SQLGetStmtAttr' Yes ISO 92 Returns the value of a statement attribute. `SQLSetStmtOption' Yes DeprecatedSets a statement option `SQLGetStmtOption' Yes DeprecatedReturns the value of a statement option *Preparing SQL requests* Function name C/ODBC Standard Purpose 3.51 `SQLAllocStmt' Yes DeprecatedAllocates a statement handle `SQLPrepare' Yes ISO 92 Prepares an SQL statement for later execution. `SQLBindParameter' Yes ODBC Assigns storage for a parameter in an SQL statement. `SQLGetCursorName' Yes ISO 92 Returns the cursor name associated with a statement handle. `SQLSetCursorName' Yes ISO 92 Specifies a cursor name. `SQLSetScrollOptions'Yes ODBC Sets options that control cursor behavior. *Submitting requests* Function name C/ODBC Standard Purpose 3.51 `SQLExecute' Yes ISO 92 Executes a prepared statement. `SQLExecDirect' Yes ISO 92 Executes a statement `SQLNativeSql' Yes ODBC Returns the text of an SQL statement as translated by the driver. `SQLDescribeParam' Yes ODBC Returns the description for a specific parameter in a statement. `SQLNumParams' Yes ISO 92 Returns the number of parameters in a statement. `SQLParamData' Yes ISO 92 Used in conjunction with `SQLPutData' to supply parameter data at execution time. (Useful for long data values.) `SQLPutData' Yes ISO 92 Sends part or all of a data value for a parameter. (Useful for long data values.) *Retrieving results and information about results* Function name C/ODBC Standard Purpose 3.51 `SQLRowCount' Yes ISO 92 Returns the number of rows affected by an insert, update, or delete request. `SQLNumResultCols' Yes ISO 92 Returns the number of columns in the result set. `SQLDescribeCol' Yes ISO 92 Describes a column in the result set. `SQLColAttribute' Yes ISO 92 Describes attributes of a column in the result set. `SQLColAttributes' Yes DeprecatedDescribes attributes of a column in the result set. `SQLFetch' Yes ISO 92 Returns multiple result rows. `SQLFetchScroll' Yes ISO 92 Returns scrollable result rows. `SQLExtendedFetch' Yes DeprecatedReturns scrollable result rows. `SQLSetPos' Yes ODBC Positions a cursor within a fetched block of data and enables an application to refresh data in the rowset or to update or delete data in the result set. `SQLBulkOperations' Yes ODBC Performs bulk insertions and bulk bookmark operations, including update, delete, and fetch by bookmark. *Retrieving error or diagnostic information* Function name C/ODBC Standard Purpose 3.51 `SQLError' Yes DeprecatedReturns additional error or status information `SQLGetDiagField' Yes ISO 92 Returns additional diagnostic information (a single field of the diagnostic data structure). `SQLGetDiagRec' Yes ISO 92 Returns additional diagnostic information (multiple fields of the diagnostic data structure). *Obtaining information about the data source's system tables (catalog functions) item* Function name C/ODBC Standard Purpose 3.51 `SQLColumnPrivileges'Yes ODBC Returns a list of columns and associated privileges for one or more tables. `SQLColumns' Yes X/Open Returns the list of column names in specified tables. `SQLForeignKeys' Yes ODBC Returns a list of column names that make up foreign keys, if they exist for a specified table. `SQLPrimaryKeys' Yes ODBC Returns the list of column names that make up the primary key for a table. `SQLSpecialColumns' Yes X/Open Returns information about the optimal set of columns that uniquely identifies a row in a specified table, or the columns that are automatically updated when any value in the row is updated by a transaction. `SQLStatistics' Yes ISO 92 Returns statistics about a single table and the list of indexes associated with the table. `SQLTablePrivileges'Yes ODBC Returns a list of tables and the privileges associated with each table. `SQLTables' Yes X/Open Returns the list of table names stored in a specific data source. *Performing transactions* Function name C/ODBC Standard Purpose 3.51 `SQLTransact' Yes DeprecatedCommits or rolls back a transaction `SQLEndTran' Yes ISO 92 Commits or rolls back a transaction. *Terminating a statement* Function name C/ODBC Standard Purpose 3.51 `SQLFreeStmt' Yes ISO 92 Ends statement processing, discards pending results, and, optionally, frees all resources associated with the statement handle. `SQLCloseCursor' Yes ISO 92 Closes a cursor that has been opened on a statement handle. `SQLCancel' Yes ISO 92 Cancels an SQL statement. *Terminating a connection* Function name C/ODBC Standard Purpose 3.51 `SQLDisconnect' Yes ISO 92 Closes the connection. `SQLFreeHandle' Yes ISO 92 Releases an environment, connection, statement, or descriptor handle. `SQLFreeConnect' Yes DeprecatedReleases connection handle `SQLFreeEnv' Yes DeprecatedReleases an environment handle  File: manual.info, Node: connector-odbc-reference-datatypes, Next: connector-odbc-reference-errorcodes, Prev: connector-odbc-reference-api, Up: connector-odbc-reference 21.1.6.2 Connector/ODBC Data Types .................................. The following table illustrates how driver maps the server data types to default SQL and C data types. Native Value SQL Type C Type `bigint unsigned' `SQL_BIGINT' `SQL_C_UBIGINT' `bigint' `SQL_BIGINT' `SQL_C_SBIGINT' `bit' `SQL_BIT' `SQL_C_BIT' `bit' `SQL_CHAR' `SQL_C_CHAR' `blob' `SQL_LONGVARBINARY' `SQL_C_BINARY' `bool' `SQL_CHAR' `SQL_C_CHAR' `char' `SQL_CHAR' `SQL_C_CHAR' `date' `SQL_DATE' `SQL_C_DATE' `datetime' `SQL_TIMESTAMP' `SQL_C_TIMESTAMP' `decimal' `SQL_DECIMAL' `SQL_C_CHAR' `double precision' `SQL_DOUBLE' `SQL_C_DOUBLE' `double' `SQL_FLOAT' `SQL_C_DOUBLE' `enum' `SQL_VARCHAR' `SQL_C_CHAR' `float' `SQL_REAL' `SQL_C_FLOAT' `int unsigned' `SQL_INTEGER' `SQL_C_ULONG' `int' `SQL_INTEGER' `SQL_C_SLONG' `integer unsigned' `SQL_INTEGER' `SQL_C_ULONG' `integer' `SQL_INTEGER' `SQL_C_SLONG' `long varbinary' `SQL_LONGVARBINARY' `SQL_C_BINARY' `long varchar' `SQL_LONGVARCHAR' `SQL_C_CHAR' `longblob' `SQL_LONGVARBINARY' `SQL_C_BINARY' `longtext' `SQL_LONGVARCHAR' `SQL_C_CHAR' `mediumblob' `SQL_LONGVARBINARY' `SQL_C_BINARY' `mediumint unsigned' `SQL_INTEGER' `SQL_C_ULONG' `mediumint' `SQL_INTEGER' `SQL_C_SLONG' `mediumtext' `SQL_LONGVARCHAR' `SQL_C_CHAR' `numeric' `SQL_NUMERIC' `SQL_C_CHAR' `real' `SQL_FLOAT' `SQL_C_DOUBLE' `set' `SQL_VARCHAR' `SQL_C_CHAR' `smallint unsigned' `SQL_SMALLINT' `SQL_C_USHORT' `smallint' `SQL_SMALLINT' `SQL_C_SSHORT' `text' `SQL_LONGVARCHAR' `SQL_C_CHAR' `time' `SQL_TIME' `SQL_C_TIME' `timestamp' `SQL_TIMESTAMP' `SQL_C_TIMESTAMP' `tinyblob' `SQL_LONGVARBINARY' `SQL_C_BINARY' `tinyint unsigned' `SQL_TINYINT' `SQL_C_UTINYINT' `tinyint' `SQL_TINYINT' `SQL_C_STINYINT' `tinytext' `SQL_LONGVARCHAR' `SQL_C_CHAR' `varchar' `SQL_VARCHAR' `SQL_C_CHAR' `year' `SQL_SMALLINT' `SQL_C_SHORT'  File: manual.info, Node: connector-odbc-reference-errorcodes, Prev: connector-odbc-reference-datatypes, Up: connector-odbc-reference 21.1.6.3 Connector/ODBC Error Codes ................................... The following tables lists the error codes returned by the driver apart from the server errors. Native SQLSTATE 2 SQLSTATE 3 Error Message Code 500 01000 01000 General warning 501 01004 01004 String data, right truncated 502 01S02 01S02 Option value changed 503 01S03 01S03 No rows updated/deleted 504 01S04 01S04 More than one row updated/deleted 505 01S06 01S06 Attempt to fetch before the result set returned the first row set 506 07001 07002 `SQLBindParameter' not used for all parameters 507 07005 07005 Prepared statement not a cursor-specification 508 07009 07009 Invalid descriptor index 509 08002 08002 Connection name in use 510 08003 08003 Connection does not exist 511 24000 24000 Invalid cursor state 512 25000 25000 Invalid transaction state 513 25S01 25S01 Transaction state unknown 514 34000 34000 Invalid cursor name 515 S1000 HY000 General driver defined error 516 S1001 HY001 Memory allocation error 517 S1002 HY002 Invalid column number 518 S1003 HY003 Invalid application buffer type 519 S1004 HY004 Invalid SQL data type 520 S1009 HY009 Invalid use of null pointer 521 S1010 HY010 Function sequence error 522 S1011 HY011 Attribute can not be set now 523 S1012 HY012 Invalid transaction operation code 524 S1013 HY013 Memory management error 525 S1015 HY015 No cursor name available 526 S1024 HY024 Invalid attribute value 527 S1090 HY090 Invalid string or buffer length 528 S1091 HY091 Invalid descriptor field identifier 529 S1092 HY092 Invalid attribute/option identifier 530 S1093 HY093 Invalid parameter number 531 S1095 HY095 Function type out of range 532 S1106 HY106 Fetch type out of range 533 S1117 HY117 Row value out of range 534 S1109 HY109 Invalid cursor position 535 S1C00 HYC00 Optional feature not implemented 0 21S01 21S01 Column count does not match value count 0 23000 23000 Integrity constraint violation 0 42000 42000 Syntax error or access violation 0 42S02 42S02 Base table or view not found 0 42S12 42S12 Index not found 0 42S21 42S21 Column already exists 0 42S22 42S22 Column not found 0 08S01 08S01 Communication link failure  File: manual.info, Node: connector-odbc-usagenotes, Next: connector-odbc-support, Prev: connector-odbc-reference, Up: connector-odbc 21.1.7 Connector/ODBC Notes and Tips ------------------------------------ * Menu: * connector-odbc-usagenotes-functionality:: Connector/ODBC General Functionality * connector-odbc-usagenotes-apptips:: Connector/ODBC Application Specific Tips * connector-odbc-errors:: Connector/ODBC Errors and Resolutions (FAQ) Here are some common notes and tips for using Connector/ODBC within different environments, applications and tools. The notes provided here are based on the experiences of Connector/ODBC developers and users.  File: manual.info, Node: connector-odbc-usagenotes-functionality, Next: connector-odbc-usagenotes-apptips, Prev: connector-odbc-usagenotes, Up: connector-odbc-usagenotes 21.1.7.1 Connector/ODBC General Functionality ............................................. * Menu: * connector-odbc-usagenotes-functionality-last-insert-id:: Obtaining Auto-Increment Values * connector-odbc-usagenotes-functionality-dynamic-cursor:: Dynamic Cursor Support * connector-odbc-usagenotes-functionality-performance:: Connector/ODBC Performance * connector-odbc-usagenotes-functionality-query-timeout:: Setting ODBC Query Timeout in Windows This section provides help with common queries and areas of functionality in MySQL and how to use them with Connector/ODBC.  File: manual.info, Node: connector-odbc-usagenotes-functionality-last-insert-id, Next: connector-odbc-usagenotes-functionality-dynamic-cursor, Prev: connector-odbc-usagenotes-functionality, Up: connector-odbc-usagenotes-functionality 21.1.7.2 Obtaining Auto-Increment Values ........................................ Obtaining the value of column that uses `AUTO_INCREMENT' after an *Note `INSERT': insert. statement can be achieved in a number of different ways. To obtain the value immediately after an *Note `INSERT': insert, use a *Note `SELECT': select. query with the `LAST_INSERT_ID()' function. For example, using Connector/ODBC you would execute two separate statements, the *Note `INSERT': insert. statement and the *Note `SELECT': select. query to obtain the auto-increment value. INSERT INTO tbl (auto,text) VALUES(NULL,'text'); SELECT LAST_INSERT_ID(); If you do not require the value within your application, but do require the value as part of another *Note `INSERT': insert, the entire process can be handled by executing the following statements: INSERT INTO tbl (auto,text) VALUES(NULL,'text'); INSERT INTO tbl2 (id,text) VALUES(LAST_INSERT_ID(),'text'); Certain ODBC applications (including Delphi and Access) may have trouble obtaining the auto-increment value using the previous examples. In this case, try the following statement as an alternative: SELECT * FROM tbl WHERE auto IS NULL; This alternative method requires that `sql_auto_is_null' variable is not set to 0. See *Note server-system-variables::. See also *Note getting-unique-id::.  File: manual.info, Node: connector-odbc-usagenotes-functionality-dynamic-cursor, Next: connector-odbc-usagenotes-functionality-performance, Prev: connector-odbc-usagenotes-functionality-last-insert-id, Up: connector-odbc-usagenotes-functionality 21.1.7.3 Dynamic Cursor Support ............................... Support for the `dynamic cursor' is provided in Connector/ODBC 3.51, but dynamic cursors are not enabled by default. You can enable this function within Windows by selecting the `Enable Dynamic Cursor' check box within the ODBC Data Source Administrator. On other platforms, you can enable the dynamic cursor by adding `32' to the `OPTION' value when creating the DSN.  File: manual.info, Node: connector-odbc-usagenotes-functionality-performance, Next: connector-odbc-usagenotes-functionality-query-timeout, Prev: connector-odbc-usagenotes-functionality-dynamic-cursor, Up: connector-odbc-usagenotes-functionality 21.1.7.4 Connector/ODBC Performance ................................... The Connector/ODBC driver has been optimized to provide very fast performance. If you experience problems with the performance of Connector/ODBC, or notice a large amount of disk activity for simple queries, there are a number of aspects you should check: * Ensure that `ODBC Tracing' is not enabled. With tracing enabled, a lot of information is recorded in the tracing file by the ODBC Manager. You can check, and disable, tracing within Windows using the `Tracing' panel of the ODBC Data Source Administrator. Within Mac OS X, check the `Tracing' panel of ODBC Administrator. See *Note connector-odbc-configuration-trace::. * Make sure you are using the standard version of the driver, and not the debug version. The debug version includes additional checks and reporting measures. * Disable the Connector/ODBC driver trace and query logs. These options are enabled for each DSN, so make sure to examine only the DSN that you are using in your application. Within Windows, you can disable the Connector/ODBC and query logs by modifying the DSN configuration. Within Mac OS X and Unix, ensure that the driver trace (option value 4) and query logging (option value 524288) are not enabled.  File: manual.info, Node: connector-odbc-usagenotes-functionality-query-timeout, Prev: connector-odbc-usagenotes-functionality-performance, Up: connector-odbc-usagenotes-functionality 21.1.7.5 Setting ODBC Query Timeout in Windows .............................................. For more information on how to set the query timeout on Microsoft Windows when executing queries through an ODBC connection, read the Microsoft knowledgebase document at `http://support.microsoft.com/default.aspx?scid=kb%3Ben-us%3B153756'.  File: manual.info, Node: connector-odbc-usagenotes-apptips, Next: connector-odbc-errors, Prev: connector-odbc-usagenotes-functionality, Up: connector-odbc-usagenotes 21.1.7.6 Connector/ODBC Application Specific Tips ................................................. * Menu: * connector-odbc-usagenotes-apptips-microsoft:: Using Connector/ODBC with Microsoft Applications * connector-odbc-usagenotes-apptips-borland:: Using Connector/ODBC with Borland Applications * connector-odbc-usagenotes-apptips-coldfusion:: Using Connector/ODBC with ColdFusion * connector-odbc-usagenotes-apptips-openoffice:: Using Connector/ODBC with OpenOffice.org * connector-odbc-usagenotes-apptips-sambarserver:: Using Connector/ODBC with Sambar Server * connector-odbc-usagenotes-apptips-datajunction:: Using Connector/ODBC with Pervasive Software DataJunction * connector-odbc-usagenotes-apptips-vision:: Using Connector/ODBC with SunSystems Vision Most programs should work with Connector/ODBC, but for each of those listed here, there are specific notes and tips to improve or enhance the way you work with Connector/ODBC and these applications. With all applications you should ensure that you are using the latest Connector/ODBC drivers, ODBC Manager and any supporting libraries and interfaces used by your application. For example, on Windows, using the latest version of Microsoft Data Access Components (MDAC) will improve the compatibility with ODBC in general, and with the Connector/ODBC driver.  File: manual.info, Node: connector-odbc-usagenotes-apptips-microsoft, Next: connector-odbc-usagenotes-apptips-borland, Prev: connector-odbc-usagenotes-apptips, Up: connector-odbc-usagenotes-apptips 21.1.7.7 Using Connector/ODBC with Microsoft Applications ......................................................... * Menu: * connector-odbc-usagenotes-apptips-microsoft-access:: Microsoft Access * connector-odbc-usagenotes-apptips-microsoft-excel:: Microsoft Excel and Column Types * connector-odbc-usagenotes-apptips-microsoft-visualbasic:: Microsoft Visual Basic * connector-odbc-usagenotes-apptips-microsoft-visualinterdev:: Microsoft Visual InterDev * connector-odbc-usagenotes-apptips-microsoft-visualobjects:: Visual Objects * connector-odbc-usagenotes-apptips-microsoft-ado:: Microsoft ADO * connector-odbc-usagenotes-apptips-microsoft-asp:: Using Connector/ODBC with Active Server Pages (ASP) * connector-odbc-usagenotes-apptips-microsoft-vb-asp:: Using Connector/ODBC with Visual Basic (ADO, DAO and RDO) and ASP The majority of Microsoft applications have been tested with Connector/ODBC, including Microsoft Office, Microsoft Access and the various programming languages supported within ASP and Microsoft Visual Studio.  File: manual.info, Node: connector-odbc-usagenotes-apptips-microsoft-access, Next: connector-odbc-usagenotes-apptips-microsoft-excel, Prev: connector-odbc-usagenotes-apptips-microsoft, Up: connector-odbc-usagenotes-apptips-microsoft 21.1.7.8 Microsoft Access ......................... To improve the integration between Microsoft Access and MySQL through Connector/ODBC: * For all versions of Access, you should enable the Connector/ODBC `Return matching rows' option. For Access 2.0, you should additionally enable the `Simulate ODBC 1.0' option. * You should have a *Note `TIMESTAMP': datetime. column in all tables that you want to be able to update. For maximum portability, do not use a length specification in the column declaration (which is unsupported within MySQL in versions earlier than 4.1). * You should have a primary key in each MySQL table you want to use with Access. If not, new or updated rows may show up as `#DELETED#'. * Use only *Note `DOUBLE': numeric-types. float fields. Access fails when comparing with single-precision floats. The symptom usually is that new or updated rows may show up as `#DELETED#' or that you cannot find or update rows. * If you are using Connector/ODBC to link to a table that has a *Note `BIGINT': numeric-types. column, the results are displayed as `#DELETED#'. The work around solution is: * Have one more dummy column with *Note `TIMESTAMP': datetime. as the data type. * Select the `Change BIGINT columns to INT' option in the connection dialog in ODBC DSN Administrator. * Delete the table link from Access and re-create it. Old records may still display as `#DELETED#', but newly added/updated records are displayed properly. * If you still get the error `Another user has changed your data' after adding a *Note `TIMESTAMP': datetime. column, the following trick may help you: Do not use a `table' data sheet view. Instead, create a form with the fields you want, and use that `form' data sheet view. You should set the `DefaultValue' property for the *Note `TIMESTAMP': datetime. column to `NOW()'. It may be a good idea to hide the *Note `TIMESTAMP': datetime. column from view so your users are not confused. * In some cases, Access may generate SQL statements that MySQL cannot understand. You can fix this by selecting `"Query|SQLSpecific|Pass-Through"' from the Access menu. * On Windows NT, Access reports *Note `BLOB': blob. columns as `OLE OBJECTS'. If you want to have `MEMO' columns instead, you should change *Note `BLOB': blob. columns to *Note `TEXT': blob. with *Note `ALTER TABLE': alter-table. * Access cannot always handle the MySQL *Note `DATE': datetime. column properly. If you have a problem with these, change the columns to *Note `DATETIME': datetime. * If you have in Access a column defined as `BYTE', Access tries to export this as *Note `TINYINT': numeric-types. instead of `TINYINT UNSIGNED'. This gives you problems if you have values larger than 127 in the column. * If you have very large (long) tables in Access, it might take a very long time to open them. Or you might run low on virtual memory and eventually get an `ODBC Query Failed' error and the table cannot open. To deal with this, select the following options: * Return Matching Rows (2) * Allow BIG Results (8). These add up to a value of 10 (`OPTION=10'). Some external articles and tips that may be useful when using Access, ODBC and Connector/ODBC: * Read How to Trap ODBC Login Error Messages in Access (http://support.microsoft.com/support/kb/articles/Q124/9/01.asp?LN=EN-US&SD=gn&FR=0%3CP%3E) * Optimizing Access ODBC Applications * Optimizing for Client/Server Performance (http://support.microsoft.com/default.aspx?scid=kb;en-us;128808) * Tips for Converting Applications to Using ODBCDirect (http://support.microsoft.com/default.aspx?scid=kb;en-us;164481) * Tips for Optimizing Queries on Attached SQL Tables (http://support.microsoft.com/default.aspx?scid=kb;EN-US;q99321) * For a list of tools that can be used with Access and ODBC data sources, refer to http://www.mysql.com/portal/software/convertors/ section for list of available tools.  File: manual.info, Node: connector-odbc-usagenotes-apptips-microsoft-excel, Next: connector-odbc-usagenotes-apptips-microsoft-visualbasic, Prev: connector-odbc-usagenotes-apptips-microsoft-access, Up: connector-odbc-usagenotes-apptips-microsoft 21.1.7.9 Microsoft Excel and Column Types ......................................... If you have problems importing data into Microsoft Excel, particularly numeric, date, and time values, this is probably because of a bug in Excel, where the column type of the source data is used to determine the data type when that data is inserted into a cell within the worksheet. The result is that Excel incorrectly identifies the content and this affects both the display format and the data when it is used within calculations. To address this issue, use the `CONCAT()' function in your queries. The use of `CONCAT()' forces Excel to treat the value as a string, which Excel will then parse and usually correctly identify the embedded information. However, even with this option, some data may be incorrectly formatted, even though the source data remains unchanged. Use the `Format Cells' option within Excel to change the format of the displayed information.  File: manual.info, Node: connector-odbc-usagenotes-apptips-microsoft-visualbasic, Next: connector-odbc-usagenotes-apptips-microsoft-visualinterdev, Prev: connector-odbc-usagenotes-apptips-microsoft-excel, Up: connector-odbc-usagenotes-apptips-microsoft 21.1.7.10 Microsoft Visual Basic ................................ To be able to update a table, you must define a primary key for the table. Visual Basic with ADO cannot handle big integers. This means that some queries like *Note `SHOW PROCESSLIST': show-processlist. do not work properly. The fix is to use `OPTION=16384' in the ODBC connect string or to select the `Change BIGINT columns to INT' option in the Connector/ODBC connect screen. You may also want to select the `Return matching rows' option.  File: manual.info, Node: connector-odbc-usagenotes-apptips-microsoft-visualinterdev, Next: connector-odbc-usagenotes-apptips-microsoft-visualobjects, Prev: connector-odbc-usagenotes-apptips-microsoft-visualbasic, Up: connector-odbc-usagenotes-apptips-microsoft 21.1.7.11 Microsoft Visual InterDev ................................... If you have a *Note `BIGINT': numeric-types. in your result, you may get the error `[Microsoft][ODBC Driver Manager] Driver does not support this parameter'. Try selecting the `Change BIGINT columns to INT' option in the Connector/ODBC connect screen.  File: manual.info, Node: connector-odbc-usagenotes-apptips-microsoft-visualobjects, Next: connector-odbc-usagenotes-apptips-microsoft-ado, Prev: connector-odbc-usagenotes-apptips-microsoft-visualinterdev, Up: connector-odbc-usagenotes-apptips-microsoft 21.1.7.12 Visual Objects ........................ You should select the `Don't optimize column widths' option.  File: manual.info, Node: connector-odbc-usagenotes-apptips-microsoft-ado, Next: connector-odbc-usagenotes-apptips-microsoft-asp, Prev: connector-odbc-usagenotes-apptips-microsoft-visualobjects, Up: connector-odbc-usagenotes-apptips-microsoft 21.1.7.13 Microsoft ADO ....................... When you are coding with the ADO API and Connector/ODBC, you need to pay attention to some default properties that aren't supported by the MySQL server. For example, using the `CursorLocation Property' as `adUseServer' returns a result of -1 for the `RecordCount Property'. To have the right value, you need to set this property to `adUseClient', as shown in the VB code here: Dim myconn As New ADODB.Connection Dim myrs As New Recordset Dim mySQL As String Dim myrows As Long myconn.Open "DSN=MyODBCsample" mySQL = "SELECT * from user" myrs.Source = mySQL Set myrs.ActiveConnection = myconn myrs.CursorLocation = adUseClient myrs.Open myrows = myrs.RecordCount myrs.Close myconn.Close Another workaround is to use a `SELECT COUNT(*)' statement for a similar query to get the correct row count. To find the number of rows affected by a specific SQL statement in ADO, use the `RecordsAffected' property in the ADO execute method. For more information on the usage of execute method, refer to `http://msdn.microsoft.com/library/default.asp?url=/library/en-us/ado270/htm/mdmthcnnexecute.asp'. For information, see ActiveX Data Objects(ADO) Frequently Asked Questions (http://support.microsoft.com/default.aspx?scid=kb;EN-US;q183606).  File: manual.info, Node: connector-odbc-usagenotes-apptips-microsoft-asp, Next: connector-odbc-usagenotes-apptips-microsoft-vb-asp, Prev: connector-odbc-usagenotes-apptips-microsoft-ado, Up: connector-odbc-usagenotes-apptips-microsoft 21.1.7.14 Using Connector/ODBC with Active Server Pages (ASP) ............................................................. You should select the `Return matching rows' option in the DSN. For more information about how to access MySQL through ASP using Connector/ODBC, refer to the following articles: * Using MyODBC To Access Your MySQL Database Via ASP (http://www.devarticles.com/c/a/ASP/Using-MyODBC-To-Access-Your-MySQL-Database-Via-ASP/) * ASP and MySQL at DWAM.NT (http://www.dwam.net/mysql/asp_myodbc.asp) A Frequently Asked Questions list for ASP can be found at `http://support.microsoft.com/default.aspx?scid=/Support/ActiveServer/faq/data/adofaq.asp'.  File: manual.info, Node: connector-odbc-usagenotes-apptips-microsoft-vb-asp, Prev: connector-odbc-usagenotes-apptips-microsoft-asp, Up: connector-odbc-usagenotes-apptips-microsoft 21.1.7.15 Using Connector/ODBC with Visual Basic (ADO, DAO and RDO) and ASP ........................................................................... Some articles that may help with Visual Basic and ASP: * MySQL BLOB columns and Visual Basic 6 (http://dev.mysql.com/tech-resources/articles/vb-blob-handling.html) by Mike Hillyer (). * How to map Visual basic data type to MySQL types (http://dev.mysql.com/tech-resources/articles/visual-basic-datatypes.html) by Mike Hillyer ().  File: manual.info, Node: connector-odbc-usagenotes-apptips-borland, Next: connector-odbc-usagenotes-apptips-coldfusion, Prev: connector-odbc-usagenotes-apptips-microsoft, Up: connector-odbc-usagenotes-apptips 21.1.7.16 Using Connector/ODBC with Borland Applications ........................................................ * Menu: * connector-odbc-usagenotes-apptips-borland-builder:: Using Connector/ODBC with Borland Builder 4 * connector-odbc-usagenotes-apptips-borland-delphi:: Using Connector/ODBC with Delphi * connector-odbc-usagenotes-apptips-borland-cppbuilder:: Using Connector/ODBC with C++ Builder With all Borland applications where the Borland Database Engine (BDE) is used, follow these steps to improve compatibility: * Update to BDE 3.2 or newer. * Enable the `Don't optimize column widths' option in the DSN. * Enabled the `Return matching rows' option in the DSN.  File: manual.info, Node: connector-odbc-usagenotes-apptips-borland-builder, Next: connector-odbc-usagenotes-apptips-borland-delphi, Prev: connector-odbc-usagenotes-apptips-borland, Up: connector-odbc-usagenotes-apptips-borland 21.1.7.17 Using Connector/ODBC with Borland Builder 4 ..................................................... When you start a query, you can use the `Active' property or the `Open' method. Note that `Active' starts by automatically issuing a `SELECT * FROM ...' query. That may not be a good thing if your tables are large.  File: manual.info, Node: connector-odbc-usagenotes-apptips-borland-delphi, Next: connector-odbc-usagenotes-apptips-borland-cppbuilder, Prev: connector-odbc-usagenotes-apptips-borland-builder, Up: connector-odbc-usagenotes-apptips-borland 21.1.7.18 Using Connector/ODBC with Delphi .......................................... Also, here is some potentially useful Delphi code that sets up both an ODBC entry and a BDE entry for Connector/ODBC. The BDE entry requires a BDE Alias Editor that is free at a Delphi Super Page near you. (Thanks to Bryan Brunton for this): fReg:= TRegistry.Create; fReg.OpenKey('\Software\ODBC\ODBC.INI\DocumentsFab', True); fReg.WriteString('Database', 'Documents'); fReg.WriteString('Description', ' '); fReg.WriteString('Driver', 'C:\WINNT\System32\myodbc.dll'); fReg.WriteString('Flag', '1'); fReg.WriteString('Password', ''); fReg.WriteString('Port', ' '); fReg.WriteString('Server', 'xmark'); fReg.WriteString('User', 'winuser'); fReg.OpenKey('\Software\ODBC\ODBC.INI\ODBC Data Sources', True); fReg.WriteString('DocumentsFab', 'MySQL'); fReg.CloseKey; fReg.Free; Memo1.Lines.Add('DATABASE NAME='); Memo1.Lines.Add('USER NAME='); Memo1.Lines.Add('ODBC DSN=DocumentsFab'); Memo1.Lines.Add('OPEN MODE=READ/WRITE'); Memo1.Lines.Add('BATCH COUNT=200'); Memo1.Lines.Add('LANGDRIVER='); Memo1.Lines.Add('MAX ROWS=-1'); Memo1.Lines.Add('SCHEMA CACHE DIR='); Memo1.Lines.Add('SCHEMA CACHE SIZE=8'); Memo1.Lines.Add('SCHEMA CACHE TIME=-1'); Memo1.Lines.Add('SQLPASSTHRU MODE=SHARED AUTOCOMMIT'); Memo1.Lines.Add('SQLQRYMODE='); Memo1.Lines.Add('ENABLE SCHEMA CACHE=FALSE'); Memo1.Lines.Add('ENABLE BCD=FALSE'); Memo1.Lines.Add('ROWSET SIZE=20'); Memo1.Lines.Add('BLOBS TO CACHE=64'); Memo1.Lines.Add('BLOB SIZE=32'); AliasEditor.Add('DocumentsFab','MySQL',Memo1.Lines);  File: manual.info, Node: connector-odbc-usagenotes-apptips-borland-cppbuilder, Prev: connector-odbc-usagenotes-apptips-borland-delphi, Up: connector-odbc-usagenotes-apptips-borland 21.1.7.19 Using Connector/ODBC with C++ Builder ............................................... Tested with BDE 3.0. The only known problem is that when the table schema changes, query fields are not updated. BDE, however, does not seem to recognize primary keys, only the index named `PRIMARY', although this has not been a problem.  File: manual.info, Node: connector-odbc-usagenotes-apptips-coldfusion, Next: connector-odbc-usagenotes-apptips-openoffice, Prev: connector-odbc-usagenotes-apptips-borland, Up: connector-odbc-usagenotes-apptips 21.1.7.20 Using Connector/ODBC with ColdFusion .............................................. The following information is taken from the ColdFusion documentation: Use the following information to configure ColdFusion Server for Linux to use the `unixODBC' driver with Connector/ODBC for MySQL data sources. You can download Connector/ODBC at `http://dev.mysql.com/downloads/connector/odbc/'. ColdFusion version 4.5.1 enables you to use the ColdFusion Administrator to add the MySQL data source. However, the driver is not included with ColdFusion version 4.5.1. Before the MySQL driver appears in the ODBC data sources drop-down list, you must build and copy the Connector/ODBC driver to `/opt/coldfusion/lib/libmyodbc.so'. The Contrib directory contains the program `mydsn-XXX.zip' which enables you to build and remove the DSN registry file for the Connector/ODBC driver on ColdFusion applications. For more information and guides on using ColdFusion and Connector/ODBC, see the following external sites: * Troubleshooting Data Sources and Database Connectivity for Unix Platforms (http://www.macromedia.com/v1/handlers/index.cfm?ID=11328&Method=Full&PageCall=/support/index.cfm).  File: manual.info, Node: connector-odbc-usagenotes-apptips-openoffice, Next: connector-odbc-usagenotes-apptips-sambarserver, Prev: connector-odbc-usagenotes-apptips-coldfusion, Up: connector-odbc-usagenotes-apptips 21.1.7.21 Using Connector/ODBC with OpenOffice.org .................................................. Open Office (`http://www.openoffice.org') How-to: MySQL + OpenOffice (http://wiki.services.openoffice.org/wiki/Connect_MySQL_and_Base). How-to: OpenOffice + MyODBC + unixODBC (http://www.unixodbc.org/doc/OOoMySQL.pdf).  File: manual.info, Node: connector-odbc-usagenotes-apptips-sambarserver, Next: connector-odbc-usagenotes-apptips-datajunction, Prev: connector-odbc-usagenotes-apptips-openoffice, Up: connector-odbc-usagenotes-apptips 21.1.7.22 Using Connector/ODBC with Sambar Server ................................................. Sambar Server (`http://www.sambarserver.info') How-to: MyODBC + SambarServer + MySQL (http://www.sambarserver.info/article.php?sid=66).  File: manual.info, Node: connector-odbc-usagenotes-apptips-datajunction, Next: connector-odbc-usagenotes-apptips-vision, Prev: connector-odbc-usagenotes-apptips-sambarserver, Up: connector-odbc-usagenotes-apptips 21.1.7.23 Using Connector/ODBC with Pervasive Software DataJunction ................................................................... You have to change it to output *Note `VARCHAR': char. rather than *Note `ENUM': enum, as it exports the latter in a manner that causes MySQL problems.  File: manual.info, Node: connector-odbc-usagenotes-apptips-vision, Prev: connector-odbc-usagenotes-apptips-datajunction, Up: connector-odbc-usagenotes-apptips 21.1.7.24 Using Connector/ODBC with SunSystems Vision ..................................................... You should select the `Return matching rows' option.  File: manual.info, Node: connector-odbc-errors, Prev: connector-odbc-usagenotes-apptips, Up: connector-odbc-usagenotes 21.1.7.25 Connector/ODBC Errors and Resolutions (FAQ) ..................................................... The following section details some common errors and their suggested fix or alternative solution. If you are still experiencing problems, use the Connector/ODBC mailing list; see *Note connector-odbc-support-community::. Many problems can be resolved by upgrading your Connector/ODBC drivers to the latest available release. On Windows, you should also make sure that you have the latest versions of the Microsoft Data Access Components (MDAC) installed. *Questions* * 21.1.7.3.1: I have installed Connector/ODBC on Windows XP x64 Edition or Windows Server 2003 R2 x64. The installation completed successfully, but the Connector/ODBC driver does not appear in `ODBC Data Source Administrator'. * 21.1.7.3.2: When connecting or using the `Test' button in `ODBC Data Source Administrator' I get error 10061 (Cannot connect to server) * 21.1.7.3.3: The following error is reported when using transactions: `Transactions are not enabled' * 21.1.7.3.4: Access reports records as `#DELETED#' when inserting or updating records in linked tables. * 21.1.7.3.5: How do I handle Write Conflicts or Row Location errors? * 21.1.7.3.6: Exporting data from Access 97 to MySQL reports a `Syntax Error'. * 21.1.7.3.7: Exporting data from Microsoft DTS to MySQL reports a `Syntax Error'. * 21.1.7.3.8: Using ODBC.NET with Connector/ODBC, while fetching empty string (0 length), it starts giving the SQL_NO_DATA exception. * 21.1.7.3.9: Using `SELECT COUNT(*) FROM TBL_NAME' within Visual Basic and ASP returns an error. * 21.1.7.3.10: Using the `AppendChunk()' or `GetChunk()' ADO methods, the `Multiple-step operation generated errors. Check each status value' error is returned. * 21.1.7.3.11: Access Returns `Another user had modified the record that you have modified' while editing records on a Linked Table. * 21.1.7.3.12: When linking an application directly to the Connector/ODBC library under Unix/Linux, the application crashes. * 21.1.7.3.13: Applications in the Microsoft Office suite are unable to update tables that have *Note `DATE': datetime. or *Note `TIMESTAMP': datetime. columns. * 21.1.7.3.14: When connecting Connector/ODBC 5.x (Beta) to a MySQL 4.x server, the error `1044 Access denied for user 'xxx'@'%' to database 'information_schema'' is returned. * 21.1.7.3.15: When calling `SQLTables', the error `S1T00' is returned, but I cannot find this in the list of error numbers for Connector/ODBC. * 21.1.7.3.16: When linking to tables in Access 2000 and generating links to tables programmatically, rather than through the table designer interface, you may get errors about tables not existing. * 21.1.7.3.17: When I try to use batched statements, the execution of the batched statements fails. * 21.1.7.3.18: When connecting to a MySQL server using ADODB and Excel, occasionally the application fails to communicate with the server and the error `Got an error reading communication packets' appears in the error log. * 21.1.7.3.19: When using some applications to access a MySQL server using C/ODBC and outer joins, an error is reported regarding the Outer Join Escape Sequence. * 21.1.7.3.20: I can correctly store extended characters in the database (Hebrew/CJK) using C/ODBC 5.1, but when I retrieve the data, the text is not formatted correctly and I get garbled characters. * 21.1.7.3.21: I have a duplicate MySQL Connector/ODBC entry within my `Installed Programs' list, but I cannot delete one of them. * 21.1.7.3.22: When submitting queries with parameter binding using *Note `UPDATE': update, my field values are being truncated to 255 characters. * 21.1.7.3.23: Is it possible to disable data-at-execution using a flag? * 21.1.7.3.24: When you call `SQLColumns()' for a table column that is `AUTO_INCREMENT', the `NULLABLE' column of the result set is always `SQL_NULLABLE (1)'. *Questions and Answers* *21.1.7.3.1: ** I have installed Connector/ODBC on Windows XP x64 Edition or Windows Server 2003 R2 x64. The installation completed successfully, but the Connector/ODBC driver does not appear in `ODBC Data Source Administrator'. * This is not a bug, but is related to the way Windows x64 editions operate with the ODBC driver. On Windows x64 editions, the Connector/ODBC driver is installed in the `%SystemRoot%\SysWOW64' folder. However, the default `ODBC Data Source Administrator' that is available through the `Administrative Tools' or `Control Panel' in Windows x64 Editions is located in the `%SystemRoot%\system32' folder, and only searches this folder for ODBC drivers. On Windows x64 editions, you should use the ODBC administration tool located at `%SystemRoot%\SysWOW64\odbcad32.exe', this will correctly locate the installed Connector/ODBC drivers and enable you to create a Connector/ODBC DSN. This issue was originally reported as Bug#20301. *21.1.7.3.2: ** When connecting or using the `Test' button in `ODBC Data Source Administrator' I get error 10061 (Cannot connect to server) * This error can be raised by a number of different issues, including server problems, network problems, and firewall and port blocking problems. For more information, see *Note can-not-connect-to-server::. *21.1.7.3.3: ** The following error is reported when using transactions: `Transactions are not enabled' * This error indicates that you are trying to use transactions with a MySQL table that does not support transactions. Transactions are supported within MySQL when using the `InnoDB' database engine. In versions of MySQL before Mysql 5.1 you may also use the `BDB' engine. You should check the following before continuing: * Verify that your MySQL server supports a transactional database engine. Use *Note `SHOW ENGINES': show-engines. to obtain a list of the available engine types. * Verify that the tables you are updating use a transaction database engine. * Ensure that you have not enabled the `disable transactions' option in your DSN. *21.1.7.3.4: ** Access reports records as `#DELETED#' when inserting or updating records in linked tables. * If the inserted or updated records are shown as `#DELETED#' in the access, then: * If you are using Access 2000, you should get and install the newest (version 2.6 or higher) Microsoft MDAC (`Microsoft Data Access Components') from `http://support.microsoft.com/kb/110093'. This fixes a bug in Access that when you export data to MySQL, the table and column names aren't specified. You should also get and apply the Microsoft Jet 4.0 Service Pack 5 (SP5) which can be found at `http://support.microsoft.com/default.aspx?scid=kb;EN-US;q239114'. This fixes some cases where columns are marked as `#DELETED#' in Access. * For all versions of Access, you should enable the Connector/ODBC `Return matching rows' option. For Access 2.0, you should additionally enable the `Simulate ODBC 1.0' option. * You should have a timestamp in all tables that you want to be able to update. * You should have a primary key in the table. If not, new or updated rows may show up as `#DELETED#'. * Use only *Note `DOUBLE': numeric-types. float fields. Access fails when comparing with single-precision floats. The symptom usually is that new or updated rows may show up as `#DELETED#' or that you cannot find or update rows. * If you are using Connector/ODBC to link to a table that has a *Note `BIGINT': numeric-types. column, the results are displayed as `#DELETED'. The work around solution is: * Have one more dummy column with *Note `TIMESTAMP': datetime. as the data type. * Select the `Change BIGINT columns to INT' option in the connection dialog in ODBC DSN Administrator. * Delete the table link from Access and re-create it. Old records still display as `#DELETED#', but newly added/updated records are displayed properly. *21.1.7.3.5: ** How do I handle Write Conflicts or Row Location errors? * If you see the following errors, select the `Return Matching Rows' option in the DSN configuration dialog, or specify `OPTION=2', as the connection parameter: Write Conflict. Another user has changed your data. Row cannot be located for updating. Some values may have been changed since it was last read. *21.1.7.3.6: ** Exporting data from Access 97 to MySQL reports a `Syntax Error'. * This error is specific to Access 97 and versions of Connector/ODBC earlier than 3.51.02. Update to the latest version of the Connector/ODBC driver to resolve this problem. *21.1.7.3.7: ** Exporting data from Microsoft DTS to MySQL reports a `Syntax Error'. * This error occurs only with MySQL tables using the *Note `TEXT': blob. or *Note `VARCHAR': char. data types. You can fix this error by upgrading your Connector/ODBC driver to version 3.51.02 or higher. *21.1.7.3.8: ** Using ODBC.NET with Connector/ODBC, while fetching empty string (0 length), it starts giving the SQL_NO_DATA exception. * You can get the patch that addresses this problem from `http://support.microsoft.com/default.aspx?scid=kb;EN-US;q319243'. *21.1.7.3.9: ** Using `SELECT COUNT(*) FROM TBL_NAME' within Visual Basic and ASP returns an error. * This error occurs because the `COUNT(*)' expression is returning a *Note `BIGINT': numeric-types, and ADO cannot make sense of a number this big. Select the `Change BIGINT columns to INT' option (option value 16384). *21.1.7.3.10: ** Using the `AppendChunk()' or `GetChunk()' ADO methods, the `Multiple-step operation generated errors. Check each status value' error is returned. * The `GetChunk()' and `AppendChunk()' methods from ADO doesn't work as expected when the cursor location is specified as `adUseServer'. On the other hand, you can overcome this error by using `adUseClient'. A simple example can be found from `http://www.dwam.net/iishelp/ado/docs/adomth02_4.htm' *21.1.7.3.11: ** Access Returns `Another user had modified the record that you have modified' while editing records on a Linked Table. * In most cases, this can be solved by doing one of the following things: * Add a primary key for the table if one doesn't exist. * Add a timestamp column if one doesn't exist. * Only use double-precision float fields. Some programs may fail when they compare single-precision floats. If these strategies do not help, you should start by making a log file from the ODBC manager (the log you get when requesting logs from ODBCADMIN) and a Connector/ODBC log to help you figure out why things go wrong. For instructions, see *Note connector-odbc-configuration-trace::. *21.1.7.3.12: ** When linking an application directly to the Connector/ODBC library under Unix/Linux, the application crashes. * Connector/ODBC 3.51 under Unix/Linux is not compatible with direct application linking. You must use a driver manager, such as iODBC or unixODBC to connect to an ODBC source. *21.1.7.3.13: ** Applications in the Microsoft Office suite are unable to update tables that have *Note `DATE': datetime. or *Note `TIMESTAMP': datetime. columns. * This is a known issue with Connector/ODBC. You must ensure that the field has a default value (rather than `NULL' and that the default value is nonzero (that is, the default value is not `0000-00-00 00:00:00'). *21.1.7.3.14: ** When connecting Connector/ODBC 5.x (Beta) to a MySQL 4.x server, the error `1044 Access denied for user 'xxx'@'%' to database 'information_schema'' is returned. * Connector/ODBC 5.x is designed to work with MySQL 5.0 or later, taking advantage of the `INFORMATION_SCHEMA' database to determine data definition information. Support for MySQL 4.1 is planned for the final release. *21.1.7.3.15: ** When calling `SQLTables', the error `S1T00' is returned, but I cannot find this in the list of error numbers for Connector/ODBC. * The `S1T00' error indicates that a general timeout has occurred within the ODBC system and is not a MySQL error. Typically it indicates that the connection you are using is stale, the server is too busy to accept your request or that the server has gone away. *21.1.7.3.16: ** When linking to tables in Access 2000 and generating links to tables programmatically, rather than through the table designer interface, you may get errors about tables not existing. * There is a known issue with a specific version of the `msjet40.dll' that exhibits this issue. The version affected is 4.0.9025.0. Reverting to an older version will enable you to create the links. If you have recently updated your version, check your `WINDOWS' directory for the older version of the file and copy it to the drivers directory. *21.1.7.3.17: ** When I try to use batched statements, the execution of the batched statements fails. * Batched statement support was added in 3.51.18. Support for batched statements is not enabled by default. You must enable option `FLAG_MULTI_STATEMENTS', value 67108864, or select the `Allow multiple statements' flag within a GUI configuration. *21.1.7.3.18: ** When connecting to a MySQL server using ADODB and Excel, occasionally the application fails to communicate with the server and the error `Got an error reading communication packets' appears in the error log. * This error may be related to Keyboard Logger 1.1 from PanteraSoft.com, which is known to interfere with the network communication between MySQL Connector/ODBC and MySQL. *21.1.7.3.19: ** When using some applications to access a MySQL server using C/ODBC and outer joins, an error is reported regarding the Outer Join Escape Sequence. * This is a known issue with MySQL Connector/ODBC which is not correctly parsing the "Outer Join Escape Sequence", as per the specs at Microsoft ODBC Specs (http://msdn2.microsoft.com/en-us/library/ms710299.aspx). Currently, Connector/ODBC will return value > 0 when asked for `SQL_OJ_CAPABILITIES' even though no parsing takes place in the driver to handle the outer join escape sequence. *21.1.7.3.20: ** I can correctly store extended characters in the database (Hebrew/CJK) using C/ODBC 5.1, but when I retrieve the data, the text is not formatted correctly and I get garbled characters. * When using ASP and UTF8 characters you should add the following to your ASP files to ensure that the data returned is correctly encoded: Response.CodePage = 65001 Response.CharSet = "utf-8" *21.1.7.3.21: ** I have a duplicate MySQL Connector/ODBC entry within my `Installed Programs' list, but I cannot delete one of them. * This problem can occur when you upgrade an existing Connector/ODBC installation, rather than removing and then installing the updated version. *Warning*: To fix the problem you should use any working uninstallers to remove existing installations and then may have to edit the contents of the registry. Make sure you have a backup of your registry information before attempting any editing of the registry contents. *21.1.7.3.22: ** When submitting queries with parameter binding using *Note `UPDATE': update, my field values are being truncated to 255 characters. * You should ensure that the `FLAG_BIG_PACKETS' option is set for your connection. This removes the 255 character limitation on bound parameters. *21.1.7.3.23: ** Is it possible to disable data-at-execution using a flag? * If you do not wish to use data-at-execution, simply remove the corresponding calls. For example: SQLLEN ylen = SQL_LEN_DATA_AT_EXEC(10); SQLBindCol(hstmt,2,SQL_C_BINARY, buf, 10, &ylen); Would become: SQLBindCol(hstmt,2,SQL_C_BINARY, buf, 10, NULL); Note that in the call to `SQLBindCol()', &ylen has been replaced by NULL. For further information please refer to the MSDN documentation (http://msdn.microsoft.com/en-us/library/ms711010(VS.85).aspx) for `SQLBindCol()'. *21.1.7.3.24: ** When you call `SQLColumns()' for a table column that is `AUTO_INCREMENT', the `NULLABLE' column of the result set is always `SQL_NULLABLE (1)'. * This is because MySQL reports the `DEFAULT' value for such a column as `NULL'. It means, if you insert a `NULL' value into the column, you will get the next integer value for the table's `auto_increment' counter.  File: manual.info, Node: connector-odbc-support, Prev: connector-odbc-usagenotes, Up: connector-odbc 21.1.8 Connector/ODBC Support ----------------------------- * Menu: * connector-odbc-support-community:: Connector/ODBC Community Support * connector-odbc-support-bug-report:: How to Report Connector/ODBC Problems or Bugs * connector-odbc-support-patch-submission:: How to Submit a Connector/ODBC Patch * connector-odbc-support-changehistory:: Connector/ODBC Change History * connector-odbc-support-credits:: Credits There are many different places where you can get support for using Connector/ODBC. You should always try the Connector/ODBC Mailing List or Connector/ODBC Forum. See *Note connector-odbc-support-community::, for help before reporting a specific bug or issue to MySQL.  File: manual.info, Node: connector-odbc-support-community, Next: connector-odbc-support-bug-report, Prev: connector-odbc-support, Up: connector-odbc-support 21.1.8.1 Connector/ODBC Community Support ......................................... Oracle provides assistance to the user community by means of its mailing lists. For Connector/ODBC-related issues, you can get help from experienced users by using the mailing list. Archives are available online at `http://lists.mysql.com/myodbc'. For information about subscribing to MySQL mailing lists or to browse list archives, visit `http://lists.mysql.com/'. See *Note mailing-lists::. Community support from experienced users is also available through the ODBC Forum (http://forums.mysql.com/list.php?37). You may also find help from other users in the other MySQL Forums, located at `http://forums.mysql.com'. See *Note forums::.  File: manual.info, Node: connector-odbc-support-bug-report, Next: connector-odbc-support-patch-submission, Prev: connector-odbc-support-community, Up: connector-odbc-support 21.1.8.2 How to Report Connector/ODBC Problems or Bugs ...................................................... If you encounter difficulties or problems with Connector/ODBC, you should start by making a log file from the `ODBC Manager' (the log you get when requesting logs from `ODBC ADMIN') and Connector/ODBC. The procedure for doing this is described in *Note connector-odbc-configuration-trace::. Check the Connector/ODBC trace file to find out what could be wrong. You should be able to determine what statements were issued by searching for the string `>mysql_real_query' in the `myodbc.log' file. You should also try issuing the statements from the *Note `mysql': mysql. client program or from `admndemo'. This helps you determine whether the error is in Connector/ODBC or MySQL. If you find out something is wrong, please only send the relevant rows (maximum 40 rows) to the `myodbc' mailing list. See *Note mailing-lists::. Please never send the whole Connector/ODBC or ODBC log file! You should ideally include the following information with the email: * Operating system and version * Connector/ODBC version * ODBC Driver Manager type and version * MySQL server version * ODBC trace from Driver Manager * Connector/ODBC log file from Connector/ODBC driver * Simple reproducible sample Remember that the more information you can supply to us, the more likely it is that we can fix the problem! Also, before posting the bug, check the MyODBC mailing list archive at `http://lists.mysql.com/myodbc'. If you are unable to find out what is wrong, the last option is to create an archive in `tar' or Zip format that contains a Connector/ODBC trace file, the ODBC log file, and a `README' file that explains the problem. You can send this to `ftp://ftp.mysql.com/pub/mysql/upload/'. Only MySQL engineers have access to the files you upload, and we are very discreet with the data. If you can create a program that also demonstrates the problem, please include it in the archive as well. If the program works with another SQL server, you should include an ODBC log file where you perform exactly the same SQL statements so that we can compare the results between the two systems. Remember that the more information you can supply to us, the more likely it is that we can fix the problem.  File: manual.info, Node: connector-odbc-support-patch-submission, Next: connector-odbc-support-changehistory, Prev: connector-odbc-support-bug-report, Up: connector-odbc-support 21.1.8.3 How to Submit a Connector/ODBC Patch ............................................. You can send a patch or suggest a better solution for any existing code or problems by sending a mail message to .  File: manual.info, Node: connector-odbc-support-changehistory, Next: connector-odbc-support-credits, Prev: connector-odbc-support-patch-submission, Up: connector-odbc-support 21.1.8.4 Connector/ODBC Change History ...................................... The Connector/ODBC Change History (Changelog) is located with the main Changelog for MySQL. See *Note connector-odbc-news::.  File: manual.info, Node: connector-odbc-support-credits, Prev: connector-odbc-support-changehistory, Up: connector-odbc-support 21.1.8.5 Credits ................ These are the developers that have worked on the Connector/ODBC and Connector/ODBC 3.51 Drivers from MySQL AB. * Michael (Monty) Widenius * Venu Anuganti * Peter Harvey  File: manual.info, Node: connector-net, Next: connector-j, Prev: connector-odbc, Up: connectors-apis 21.2 MySQL Connector/NET ======================== * Menu: * connector-net-versions:: Connector/NET Versions * connector-net-installation:: Connector/NET Installation * connector-net-visual-studio:: Connector/NET Visual Studio Integration * connector-net-tutorials:: Connector/NET Tutorials * connector-net-programming:: Connector/NET Programming * connector-net-connection-options:: Connector/NET Connection String Options Reference * connector-net-ref:: Connector/NET API Reference * connect-net-support:: Connector/NET Support * connector-net-faq:: Connector/NET FAQ Connector/NET enables developers to easily create .NET applications that require secure, high-performance data connectivity with MySQL. It implements the required ADO.NET interfaces and integrates into ADO.NET aware tools. Developers can build applications using their choice of .NET languages. Connector/NET is a fully managed ADO.NET driver written in 100% pure C#. Connector/NET includes full support for: * Features provided by MySQL Server up to and including MySQL Server version 5.5. * Large-packet support for sending and receiving rows and BLOBs up to 2 gigabytes in size. * Protocol compression which enables compressing the data stream between the client and server. * Support for connecting using TCP/IP sockets, named pipes, or shared memory on Windows. * Support for connecting using TCP/IP sockets or Unix sockets on Unix. * Support for the Open Source Mono framework developed by Novell. * Fully managed, does not utilize the MySQL client library. This document is intended as a user's guide to Connector/NET and includes a full syntax reference. Syntax information is also included within the `Documentation.chm' file included with the Connector/NET distribution. If you are using MySQL 5.0 or later, and Visual Studio as your development environment, you may want also want to use the MySQL Visual Studio Plugin. The plugin acts as a DDEX (Data Designer Extensibility) provider, enabling you to use the data design tools within Visual Studio to manipulate the schema and objects within a MySQL database. For more information, see *Note connector-net-visual-studio::. *Note*: Connector/NET 5.1.2 and later include the Visual Studio Plugin by default. MySQL Connector/NET supports full versions of Visual Studio 2005, 2008, and 2010, although certain features are only available in Visual Studio 2010 when using MySQL Connector/NET version 6.3.2 and later. Note that MySQL Connector/NET does not currently support Express versions of Microsoft products, including Microsoft Visual Web Developer. *Key topics:* * For connection string properties when using the MySqlConnection class, see *Note connector-net-connection-options::.  File: manual.info, Node: connector-net-versions, Next: connector-net-installation, Prev: connector-net, Up: connector-net 21.2.1 Connector/NET Versions ----------------------------- There are several versions of Connector/NET available: * Connector/NET 1.0 includes support for MySQL Server 4.0, 4.1, and 5.0 features, and full compatibility with the ADO.NET driver interface. This version of Connector/NET is no longer supported. * Connector/NET 5.0 includes support for MySQL Server 4.0, 4.1, 5.0 and 5.1 features. Connector/NET 5.0 also includes full support for the ADO.Net 2.0 interfaces and subclasses, includes support for the usage advisor and performance monitor (PerfMon) hooks. This version of Connector/NET is no longer supported. * Connector/NET 5.1 includes support for MySQL Server 4.0, 4.1, 5.0, 5.1, 5.4 and 5.5 features. Connector/NET 5.1 also includes support for a new membership/role provider, Compact Framework 2.0, a new stored procedure parser and improvements to `GetSchema'. Connector/NET 5.1 also includes the Visual Studio Plugin as a standard installable component. This version of Connector/NET is no longer supported. * Connector/NET 5.2 includes support for MySQL Server 4.1, 5.0, 5.1, 5.4, and 5.5 features. Connector/NET 5.2 also includes support for a new membership/role provider, Compact Framework 2.0, a new stored procedure parser and improvements to `GetSchema'. Connector/NET 5.2 also includes the Visual Studio Plugin as a standard installable component. This version of Connector/NET is no longer supported. * Connector/NET 6.0 includes support for MySQL Server 4.1, 5.0, 5.1, 5.4 and 5.5. This version of Connector/NET is no longer supported. * Connector/NET 6.1 includes support for MySQL Server 4.1, 5.0, 5.1, 5.4, and 5.5. Important new features include the MySQL Website Configuration Tool and a Session State Provider. * Connector/NET 6.2 includes support for MySQL Server 4.1, 5.0, 5.1, 5.4, and 5.5. Important new features include a new logging system and client SSL certificates. Connector/NET 6.2 is currently available as a Beta release. * Connector/NET 6.3 includes support for MySQL Server 5.0, 5.1, 5.4, and 5.5. Important new features include integration with Visual Studio 2010, such as availability of DDL T4 template for Entity Framework, and a custom MySQL SQL Editor. Other features include refactored transaction scope: Connector/NET now supports nested transactions in a scope where they use the same connection string. Connector/NET 6.3 is available as a Beta release. The latest source code for Connector/NET can be downloaded from the MySQL public Subversion server. For further details see *Note connector-net-installation-source::. The following table shows the .NET Framework version required, and MySQL Server version supported by Connector/NET: Connector/NET ADO.NET version .NET Framework MySQL Server Currently version supported version required version supported supported 1.0 1.x 1.x 4.0, 4.1, 5.0 No 5.0 2.x+ 2.x+ 4.0, 4.1, 5.0 No 5.1 2.x+ 2.x+ 4.0, 4.1, 5.0, No 5.1, 5.4, 5.5 5.2 2.x+ 2.x+ 4.1, 5.0, 5.1, No 5.4, 5.5 6.0 2.x+ 2.x+ 4.1, 5.0, 5.1, Critical issues 5.4, 5.5 only 6.1 2.x+ 2.x+ 4.1, 5.0, 5.1, Yes 5.4, 5.5 6.2 2.x+ 2.x+ 4.1, 5.0, 5.1, Yes 5.4, 5.5 6.3 2.x+ 2.x+, 4.x+ for VS 5.0, 5.1, 5.4, 5.5 Yes 2010 support *Note*: Version numbers for MySQL products are formatted as X.Y.Z, where Z=0 indicates alpha, Z=1 indicates beta, and Z>=2 indicates GA. However, Windows tools (Control Panel, properties display) may show the version numbers as XX.YY.ZZ. For example, the official MySQL formatted version number 5.0.9 may be displayed by Windows tools as 5.00.09. The two versions are the same; only the number display format is different.  File: manual.info, Node: connector-net-installation, Next: connector-net-visual-studio, Prev: connector-net-versions, Up: connector-net 21.2.2 Connector/NET Installation --------------------------------- * Menu: * connector-net-installation-windows:: Installing Connector/NET on Windows * connector-net-installation-unix:: Installing Connector/NET on Unix with Mono * connector-net-installation-source:: Installing Connector/NET from the source code Connector/NET runs on any platform that supports the .NET framework. The .NET framework is primarily supported on recent versions of Microsoft Windows, and is supported on Linux through the Open Source Mono framework (see `http://www.mono-project.com'). Connector/NET is available for download from `http://dev.mysql.com/downloads/connector/net/5.2.html'.  File: manual.info, Node: connector-net-installation-windows, Next: connector-net-installation-unix, Prev: connector-net-installation, Up: connector-net-installation 21.2.2.1 Installing Connector/NET on Windows ............................................ * Menu: * connector-net-installation-binary-windows-installer:: Installing Connector/NET using the Installer * connector-net-installation-binary-windows-zip:: Installing Connector/NET using the Zip packages On Windows, installation is supported either through a binary installation process or by downloading a Zip file with the Connector/NET components. Before installing, you should ensure that your system is up to date, including installing the latest version of the .NET Framework.  File: manual.info, Node: connector-net-installation-binary-windows-installer, Next: connector-net-installation-binary-windows-zip, Prev: connector-net-installation-windows, Up: connector-net-installation-windows 21.2.2.2 Installing Connector/NET using the Installer ..................................................... Using the installer is the most straightforward method of installing Connector/NET on Windows and the installed components include the source code, test code and full reference documentation. Connector/NET is installed through the use of a Windows Installer (`.msi') installation package, which can be used to install Connector/NET on all Windows operating systems. The MSI package in contained within a Zip archive named `mysql-connector-net-VERSION.zip', where VERSION indicates the Connector/NET version. To install Connector/NET: 1. Double-click the MSI installer file extracted from the Zip you downloaded. Click `Next' to start the installation. Connector/NET Windows Installer - Welcome 2. You must choose the type of installation that you want to perform. Connector/NET Windows Installer - Installation type For most situations, the Typical installation will be suitable. Click the `Typical' button and proceed to Step 5. A Complete installation installs all the available files. To conduct a Complete installation, click the `Complete' button and proceed to step 5. If you want to customize your installation, including choosing the components to install and some installation options, click the `Custom' button and proceed to Step 3. The Connector/NET installer will register the connector within the Global Assembly Cache (GAC) - this will make the Connector/NET component available to all applications, not just those where you explicitly reference the Connector/NET component. The installer will also create the necessary links in the Start menu to the documentation and release notes. 3. If you have chosen a custom installation, you can select the individual components that you want to install, including the core interface component, supporting documentation (a CHM file) samples and examples and the source code. Select the items, and their installation level, and then click `Next' to continue the installation. *Note*: For Connector/NET 1.0.8 or lower and Connector 5.0.4 and lower the installer will attempt to install binaries for both 1.x and 2.x of the .NET Framework. If you only have one version of the framework installed, the connector installation may fail. If this happens, you can choose the framework version to be installed through the custom installation step. Connector/NET Windows Installer - Custom setup 4. You will be given a final opportunity to confirm the installation. Click `Install' to copy and install the files onto your machine. Connector/NET Windows Installer - Confirming installation 5. Once the installation has been completed, click `Finish' to exit the installer. Connector/NET Windows Installer - Finish installation Unless you choose otherwise, Connector/NET is installed in `C:\Program Files\MySQL\MySQL Connector Net X.X.X', where X.X.X is replaced with the version of Connector/NET you are installing. New installations do not overwrite existing versions of Connector/NET. Depending on your installation type, the installed components will include some or all of the following components: * `bin' - Connector/NET MySQL libraries for different versions of the .NET environment. * `docs' - contains a CHM of the Connector/NET documentation. * `samples' - sample code and applications that use the Connector/NET component. * `src' - the source code for the Connector/NET component. You may also use the `/quiet' or `/q' command-line option with the `msiexec' tool to install the Connector/NET package automatically (using the default options) with no notification to the user. Using this method the user cannot select options. Additionally, no prompts, messages or dialog boxes will be displayed. C:\> msiexec /package connector-net.msi /quiet To provide a progress bar to the user during automatic installation, use the `/passive' option.  File: manual.info, Node: connector-net-installation-binary-windows-zip, Prev: connector-net-installation-binary-windows-installer, Up: connector-net-installation-windows 21.2.2.3 Installing Connector/NET using the Zip packages ........................................................ If you are having problems running the installer, you can download a Zip file without an installer as an alternative. That file is called `mysql-connector-net-VERSION-noinstall.zip'. Once downloaded, you can extract the files to a location of your choice. The file contains the following directories: * `bin' - Connector/NET MySQL libraries for different versions of the .NET environment. * `Docs' - contains a CHM of the Connector/NET documentation. * `Samples' - sample code and applications that use the Connector/NET component. Connector/NET 6.0.x has a different directory structure: * `Assemblies' - contains a collection of DLLs that make up the connector functionality. * `Documentation' - contains the Connector/NET documentation as a CHM file. * `Samples' - sample code and applications that use the Connector/NET component. There is also another Zip file available for download called `mysql-connector-net-VERSION-src.zip'. This file contains the source code distribution. The file contains the following directories: * `Documentation' - This folder contains the source files to build the documentation into the compiled HTML (CHM) format. * `Installer' - This folder contains the source files to build the Connector/NET installer program. * `MySql.Data' - This folder contains the source files for the core data provider. * `MySql.VisualStudio' - This folder contains the source files for the Microsoft Visual Studio extensions. * `MySql.Web' - This folder contains the source files for the web providers. This includes code for the membership provider, role provider and profile provider. These are used in ASP.NET web sites. * `Samples' - This folder contains the source files for several example applications. * `Tests' - This folder contains a spreadsheet listing test cases. * `VisualStudio' - Contains resources used by the Visual Studio plug in. Finally, you need to ensure that `MySql.Data.dll' is accessible to your program at build time (and run time). If using Microsoft Visual Studio you will need to add `MySql.Data' as a Reference to your project. *Note*: If using MySQL Connector/NET 6.3.5 and above, the `MySql.Data' file provided will work with both .NET Framework 2.x and 4.x.  File: manual.info, Node: connector-net-installation-unix, Next: connector-net-installation-source, Prev: connector-net-installation-windows, Up: connector-net-installation 21.2.2.4 Installing Connector/NET on Unix with Mono ................................................... There is no installer available for installing the Connector/NET component on your Unix installation. Before installing, please ensure that you have a working Mono project installation. You can test whether your system has Mono installed by typing: shell> mono --version The version of the Mono JIT compiler will be displayed. To compile C# source code you will also need to make sure a Mono C# compiler, is installed. Note that there are two Mono C# compilers available, `mcs', which accesses the 1.0-profile libraries, and `gmcs', which accesses the 2.0-profile libraries. To install Connector/NET on Unix/Mono: 1. Download the `mysql-connector-net-VERSION-noinstall.zip' and extract the contents to a directory of your choice, for example: `~/connector-net/'. 2. In the directory where you unzipped the connector to, change into the `bin' directory. Ensure the file `MySql.Data.dll' is present. 3. You must register the Connector/NET component, `MySql.Data', in the Global Assembly Cache (GAC). In the current directory enter the `gacutil' command: root-shell> gacutil /i MySql.Data.dll This will register `MySql.Data' into the GAC. You can check this by listing the contents of `/usr/lib/mono/gac', where you will find `MySql.Data' if the registration has been successful. You are now ready to compile your application. You must ensure that when you compile your application you include the Connector/NET component using the `-r:' command-line option. For example: shell> gmcs -r:System.dll -r:System.Data.dll -r:MySql.Data.dll HelloWorld.cs Note, the assemblies that need to be referenced will depend on the requirements of the application, but applications using Connector/NET will need to provide `-r:MySql.Data' as a minimum. You can further check your installation by running the compiled program, for example: shell> mono HelloWorld.exe  File: manual.info, Node: connector-net-installation-source, Prev: connector-net-installation-unix, Up: connector-net-installation 21.2.2.5 Installing Connector/NET from the source code ...................................................... *Caution*: You should read this section only if you are interested in helping us test our new code. If you just want to get Connector/NET up and running on your system, you should use a standard release distribution. *Obtaining the source code* To obtain the most recent development source tree, you first need to download and install Bazaar. You can obtain Bazaar from the Bazaar VCS Website (http://bazaar-vcs.org). Bazaar is supported by any platform that supports Python, and is therefore compatible with any Linux, Unix, Windows or Mac OS X host. Instructions for downloading and installing Bazaar on the different platforms are available on the Bazaar Web site. The most recent development source tree is available from our public Subversion trees at `http://dev.mysql.com/tech-resources/sources.html'. To check out out the Connector/NET sources, change to the directory where you want the copy of the Connector/NET tree to be stored, then use the following command: shell> bzr branch lp:connectornet/trunk To download a specific version of Connector/NET, specify the version number instead of `trunk'. For example, to obtain a copy of the 6.0 version of the source tree: shell> bzr branch lp:connectornet/6.0 Source packages are also available on the downloads page. *Building the source code on Windows* The following procedure can be used to build the connector on Microsoft Windows. * Obtain the source code, either from the Subversion server, or through one of the prepared source code packages. * Navigate to the root of the source code tree. * A Microsoft Visual Studio 2005 solution file is available to build the connector, this is called `MySQL-VS2005.sln'. Click this file to load the solution into Visual Studio. * Select `Build', `Build Solution' from the main menu to build the solution. *Building the source code on Unix* Support for building Connector/NET on Mono/Unix is currently not available.  File: manual.info, Node: connector-net-visual-studio, Next: connector-net-tutorials, Prev: connector-net-installation, Up: connector-net 21.2.3 Connector/NET Visual Studio Integration ---------------------------------------------- * Menu: * connector-net-visual-studio-making-a-connection:: Making a connection * connector-net-visual-studio-editing-tables:: Editing Tables * connector-net-visual-studio-editing-views:: Editing Views * connector-net-visual-studio-editing-stored-procedures-and-functions:: Editing Stored Procedures and Functions * connector-net-visual-studio-editing-triggers:: Editing Triggers * connector-net-visual-studio-editing-user-defined-functions-udf:: Editing User Defined Functions (UDF) * connector-net-visual-studio-cloning-database-objects:: Cloning Database Objects * connector-net-visual-studio-dropping-database-objects:: Dropping Database Objects * connector-net-visual-studio-entity-framework:: Using the ADO.NET Entity Framework * connector-net-website-config:: MySQL Website Configuration Tool * connector-net-sql-editor:: MySQL SQL Editor * connector-net-ddl-t4-ef:: DDL T4 Template Macro When MySQL Connector/NET is installed on Microsoft Windows, Visual Studio integration components are also installed and initialized. This enables the developer to work seamlessly with MySQL Connector/NET in the familiar Visual Studio environment, as described in the following sections of the manual. MySQL Connector/NET supports Visual Studio versions 2005, 2008, and 2010. However, only MySQL Connector/NET version 6.3 fully integrates with Visual Studio 2010, although applications using earlier versions of the connector can be built with the Visual Studio 2010 environment using .NET 2.x frameworks. Visual Studio 2010 support was introduced with MySQL Connector/NET 6.3.2. From version 6.3.2 the connector ships with both .NET 2.x and .NET 4.x versions of the entity framework support files, `mysql.data.ef.dll' and ` mysql.visualstudio.dll'. The .NET 4.x versions need to be shipped to enable new integration features supported in Visual Studio 2010, including: * New DDL T4 template for the Entity Framework (EF) - This enables developers to design an EF model from scratch and use the native Visual Studio 2010 facility to generate MySQL DDL from that model. This is done by creating the model, and with the model open, choosing the SSDLToMySQL template in the properties window. The correct DDL is then generated. The developer can then save this code as a `.mysql' file in their project and execute it against the MySQL server. * New SQL Editor - A new SQL editor has been included that enables connections to servers to execute SQL. This is activated by creating a new file with a `.mysql' extension. A new template is also included to allow creation of this file type using the Visual Studio 2010 main menu item `File', `New'. Note that the MySQL SQL Editor is also available in 2005 and 2008.  File: manual.info, Node: connector-net-visual-studio-making-a-connection, Next: connector-net-visual-studio-editing-tables, Prev: connector-net-visual-studio, Up: connector-net-visual-studio 21.2.3.1 Making a connection ............................ Once the connector is installed, you can use it to create, modify, and delete connections to MySQL databases. To create a connection with a MySQL database, perform the following steps: * Start Visual Studio, and open the Server Explorer window (`View', `Server Explorer' option in the main Visual Studio menu, or `Control+W', `L' keyboard shortcuts). * Right-click the Data Connections node, and choose the `Add Connection...' menu item. * Add Connection dialog opens. Press the `Change' button to choose MySQL Database as a data source. FIGURE GOES HERE: Add Connection Context Menu * Change Data Source dialog opens. Choose MySQL Database in the list of data sources (or the `' option, if MySQL Database is absent), and then choose .NET Framework Data Provider for MySQL in the combo box of data providers. FIGURE GOES HERE: Choose Data Source * Input the connection settings: the server host name (for example, localhost if the MySQL server is installed on the local machine), the user name, the password, and the default schema name. Note that you must specify the default schema name to open the connection. FIGURE GOES HERE: Add Connection Dialog * You can also set the port to connect with the MySQL server by pressing the `Advanced' button. To test connection with the MySQL server, set the server host name, the user name, and the password, and press the `Test Connection' button. If the test succeeds, the success confirmation dialog opens. * After you set all settings and test the connection, press `OK'. The newly created connection is displayed in Server Explorer. Now you can work with the MySQL server through standard Server Explorer GUI. FIGURE GOES HERE: New Data Connection After the connection is successfully established, all settings are saved for future use. When you start Visual Studio for the next time, just open the connection node in Server Explorer to establish a connection to the MySQL server again. To modify and delete a connection, use the Server Explorer context menu for the corresponding node. You can modify any of the settings just by overwriting the existing values with new ones. Note that the connection may be modified or deleted only if no active editor for its objects is opened: otherwise you may loose your data.  File: manual.info, Node: connector-net-visual-studio-editing-tables, Next: connector-net-visual-studio-editing-views, Prev: connector-net-visual-studio-making-a-connection, Up: connector-net-visual-studio 21.2.3.2 Editing Tables ....................... * Menu: * connector-net-visual-studio-editing-tables-column-editor:: Column Editor * connector-net-visual-studio-editing-tables-indexes:: Editing Indexes * connector-net-visual-studio-editing-tables-foreign-keys:: Editing Foreign Keys * connector-net-visual-studio-editing-tables-column-details:: Column Properties * connector-net-visual-studio-editing-tables-table-properties:: Table Properties Connector/Net contains a table editor, which enables the visual creation and modification of tables. The Table Designer can be accessed through a mouse action on table-type node of Server Explorer. To create a new table, right-click the `Tables' node (under the connection node) and choose the `Create Table' command from the context menu. To modify an existing table, double-click the node of the table you wish to modify, or right-click this node and choose the `Design' item from the context menu. Either of the commands opens the Table Designer. The table editor is implemented in the manner of the well-known Query Browser Table Editor, but with minor differences. FIGURE GOES HERE: Editing New Table Table Designer consists of the following parts: * Columns Editor - a data grid on top of the Table Designer. Use the Columns grid for column creation, modification, and deletion. * Indexes tab - a tab on bottom of the Table Designer. Use the Indexes tab for indexes management. * Foreign Keys tab - a tab on bottom of the Table Designer. Use the Foreign Keys tab for foreign keys management. * Column Details tab - a tab on bottom of the Table Designer. Use the Column Details tab to set advanced column options. * Properties window - a standard Visual Studio Properties window, where the properties of the edited table are displayed. Use the Properties window to set the table properties. Each of these areas is discussed in more detail in subsequent sections. To save changes you have made in the Table Designer, use either `Save' or `Save All' button of the Visual Studio main toolbar, or just press `Control+S'. If you have not already named the table you will be prompted to do so. FIGURE GOES HERE: Choose Table Name Once created you can view the table in the Server Explorer. FIGURE GOES HERE: Newly Created Table The Table Designer main menu enables you to set a Primary Key column, edit Relationships such as Foreign Keys, and create Indexes. FIGURE GOES HERE: Table Designer Main Menu  File: manual.info, Node: connector-net-visual-studio-editing-tables-column-editor, Next: connector-net-visual-studio-editing-tables-indexes, Prev: connector-net-visual-studio-editing-tables, Up: connector-net-visual-studio-editing-tables 21.2.3.3 Column Editor ...................... You can use the Column Editor to set or change the name, data type, default value, and other properties of a table column. To set the focus to a needed cell of a grid, use the mouse click. Also you can move through the grid using `Tab' and `Shift'+`Tab' keys. To set or change the name, data type, default value and comment of a column, activate the appropriate cell and type the desired value. To set or unset flag-type column properties (`NOT NULL', auto incremented, flags), check or uncheck the corresponding check boxes. Note that the set of column flags depends on its data type. To reorder columns, index columns or foreign key columns in the Column Editor, select the whole column you wish to reorder by clicking the selector column on the left of the column grid. Then move the column by using `Control+Up' (to move the column up) or `Control+Down' (to move the column down) keys. To delete a column, select it by clicking the selector column on the left of the column grid, then press the `Delete' button on a keyboard.  File: manual.info, Node: connector-net-visual-studio-editing-tables-indexes, Next: connector-net-visual-studio-editing-tables-foreign-keys, Prev: connector-net-visual-studio-editing-tables-column-editor, Up: connector-net-visual-studio-editing-tables 21.2.3.4 Editing Indexes ........................ Indexes management is performed using the `Indexes/Keys' dialog. To add an index, select `Table Designer', `Indexes/Keys...' from the main menu, and click `Add' to add a new index. You can then set the index name, index kind, index type, and a set of index columns. FIGURE GOES HERE: Indexes Dialog To remove an index, select it in the list box on the left, and click the `Delete' button. To change index settings, select the needed index in the list box on the left. The detailed information about the index is displayed in the panel on the right hand side. Change the desired values.  File: manual.info, Node: connector-net-visual-studio-editing-tables-foreign-keys, Next: connector-net-visual-studio-editing-tables-column-details, Prev: connector-net-visual-studio-editing-tables-indexes, Up: connector-net-visual-studio-editing-tables 21.2.3.5 Editing Foreign Keys ............................. Foreign Keys management is performed using the `Foreign Key Relationships' dialog. To add a foreign key, select `Table Designer', `Relationships...' from the main menu. This displays the `Foreign Key Relationship' dialog. Click `Add'. You can then set the foreign key name, referenced table name, foreign key columns, and actions upon update and delete. To remove a foreign key, select it in the list box on the left, and click the `Delete' button. To change foreign key settings, select the required foreign key in the list box on the left. The detailed information about the foreign key is displayed in the right hand panel. Change the desired values. FIGURE GOES HERE: Foreign Key Relationships Dialog  File: manual.info, Node: connector-net-visual-studio-editing-tables-column-details, Next: connector-net-visual-studio-editing-tables-table-properties, Prev: connector-net-visual-studio-editing-tables-foreign-keys, Up: connector-net-visual-studio-editing-tables 21.2.3.6 Column Properties .......................... The `Column Properties' tab can be used to set column options. In addition to the general column properties presented in the Column Editor, in the `Column Properties' tab you can set additional properties such as Character Set, Collation and Precision.  File: manual.info, Node: connector-net-visual-studio-editing-tables-table-properties, Prev: connector-net-visual-studio-editing-tables-column-details, Up: connector-net-visual-studio-editing-tables 21.2.3.7 Table Properties ......................... To bring up Table Properties select the table and right-click to activate the context menu. Select `Properties'. The `Table Properties' dockable window will be displayed. FIGURE GOES HERE: Table Properties Menu Item The following table properties can be set: * Auto Increment * Average Row Length * Character Set * Collation * Comment * Data Directory * Index Directory * Maximum Rows * Minimum Rows * Name * Row Format * Schema * Storage Engine The property `Schema' is read only. FIGURE GOES HERE: Table Properties  File: manual.info, Node: connector-net-visual-studio-editing-views, Next: connector-net-visual-studio-editing-stored-procedures-and-functions, Prev: connector-net-visual-studio-editing-tables, Up: connector-net-visual-studio 21.2.3.8 Editing Views ...................... To create a new view, right-click the Views node under the connection node in Server Explorer. From the node's context menu, choose the `Create View' command. This command opens the SQL Editor. FIGURE GOES HERE: Editing View SQL You can then enter the SQL for your view. FIGURE GOES HERE: View SQL Added To modify an existing view, double-click a node of the view you wish to modify, or right-click this node and choose the `Alter View' command from a context menu. Either of the commands opens the SQL Editor. All other view properties can be set in the Properties window. These properties are: * Catalog * Check Option * Definer * Definition * Definer * Is Updateable * Name * Schema * Security Type Some of these properties can have arbitrary text values, others accept values from a predefined set. In the latter case you set the desired value with an embedded combobox. The properties `Is Updatable' and `Schema' are readonly. To save changes you have made, use either `Save' or `Save All' buttons of the Visual Studio main toolbar, or just press `Control+S'. FIGURE GOES HERE: View SQL Saved  File: manual.info, Node: connector-net-visual-studio-editing-stored-procedures-and-functions, Next: connector-net-visual-studio-editing-triggers, Prev: connector-net-visual-studio-editing-views, Up: connector-net-visual-studio 21.2.3.9 Editing Stored Procedures and Functions ................................................ To create a new stored procedure, right-click the `Stored Procedures' node under the connection node in Server Explorer. From the node's context menu, choose the `Create Routine' command. This command opens the SQL Editor. FIGURE GOES HERE: Edit Stored Procedure SQL To create a new stored function, right-click the `Functions' node under the connection node in Server Explorer. From the node's context menu, choose the `Create Routine' command. To modify an existing stored routine (procedure or function), double-click the node of the routine you wish to modify, or right-click this node and choose the `Alter Routine' command from the context menu. Either of the commands opens the SQL Editor. To create or alter the routine definition using SQL Editor, type this definition in the SQL Editor using standard SQL. All other routine properties can be set in the Properties window. These properties are: * Body * Catalog * Comment * Creation Time * Data Access * Definer * Definition * External Name * External Language * Is Deterministic * Last Modified * Name * Parameter Style * Returns * Schema * Security Type * Specific Name * SQL Mode * SQL Path * Type Some of these properties can have arbitrary text values, others accept values from a predefined set. In the latter case set the desired value using the embedded combo box. You can also set all the options directly in the SQL Editor, using the standard `CREATE PROCEDURE' or `CREATE FUNCTION' statement. However, it is recommended to use the Properties window instead. To save changes you have made, use either `Save' or `Save All' buttons of the Visual Studio main toolbar, or just press `Control+S'. FIGURE GOES HERE: Stored Procedure SQL Saved  File: manual.info, Node: connector-net-visual-studio-editing-triggers, Next: connector-net-visual-studio-editing-user-defined-functions-udf, Prev: connector-net-visual-studio-editing-stored-procedures-and-functions, Up: connector-net-visual-studio 21.2.3.10 Editing Triggers .......................... To create a new trigger, right-click the node of the table, for which you wish to add a trigger. From the node's context menu, choose the `Create Trigger' command. This command opens the SQL Editor. To modify an existing trigger, double-click the node of the trigger you wish to modify, or right-click this node and choose the `Alter Trigger' command from the context menu. Either of the commands opens the SQL Editor. To create or alter the trigger definition using SQL Editor, type the trigger statement in the SQL Editor using standard SQL. *Note*: You should enter only the trigger statement, that is, the part of the `CREATE TRIGGER' query that is placed after the `FOR EACH ROW' clause. All other trigger properties are set in the Properties window. These properties are: * Definer * Event Manipulation * Name * Timing Some of these properties can have arbitrary text values, others accept values from a predefined set. In the latter case set the desired value using the embedded combo box. The properties `Event Table', `Schema', and `Server' in the Properties window are read only. To save changes you have made, use either `Save' or `Save All' buttons of the Visual Studio main toolbar, or just press `Control+S'. Before changes are saved, you will be asked to confirm the execution of the corresponding SQL query in a confirmation dialog.  File: manual.info, Node: connector-net-visual-studio-editing-user-defined-functions-udf, Next: connector-net-visual-studio-cloning-database-objects, Prev: connector-net-visual-studio-editing-triggers, Up: connector-net-visual-studio 21.2.3.11 Editing User Defined Functions (UDF) .............................................. To create a new User Defined Function (UDF), right-click the `UDFs' node under the connection node in Server Explorer. From the node's context menu, choose the `Create UDF' command. This command opens the UDF Editor. To modify an existing UDF, double-click the node of the UDF you wish to modify, or right-click this node and choose the `Alter UDF' command from the context menu. Either of the commands opens the UDF Editor. The UDF editor enables you to set the following properties: * Name * So-name (DLL name) * Return type * Is Aggregate There are text fields for both names, a combo box for the return type, and a check box to indicate if the UDF is aggregate. All these options are also accessible using the Properties window. The property `Server' in the Properties window is read only. To save changes you have made, use either `Save' or `Save All' buttons of the Visual Studio main toolbar, or just press `Control+S'. Before changes are saved, you will be asked to confirm the execution of the corresponding SQL query in a confirmation dialog.  File: manual.info, Node: connector-net-visual-studio-cloning-database-objects, Next: connector-net-visual-studio-dropping-database-objects, Prev: connector-net-visual-studio-editing-user-defined-functions-udf, Up: connector-net-visual-studio 21.2.3.12 Cloning Database Objects .................................. Tables, views, stored procedures, and functions can be cloned using the appropriate Clone command from the context menu: `Clone Table', `Clone View', `Clone Routine'. The clone commands open the corresponding editor for a new object: the `Table Editor' for cloning a table, and the `SQL Editor' for cloning a view or a routine. The editor is filled with values of the original object. You can modify these values in a usual manner. To save the cloned object, use either Save or Save All buttons of the Visual Studio main toolbar, or just press `Control+S'. Before changes are saved, you will be asked to confirm the execution of the corresponding SQL query in a confirmation dialog.  File: manual.info, Node: connector-net-visual-studio-dropping-database-objects, Next: connector-net-visual-studio-entity-framework, Prev: connector-net-visual-studio-cloning-database-objects, Up: connector-net-visual-studio 21.2.3.13 Dropping Database Objects ................................... Tables, views, stored routines, triggers, and UDFs can be dropped with the appropriate Drop command selected from its context menu: `Drop Table', `Drop View', `Drop Routine', `Drop Trigger', `Drop UDF'. You will be asked to confirm the execution of the corresponding drop query in a confirmation dialog. Dropping of multiple objects is not supported.  File: manual.info, Node: connector-net-visual-studio-entity-framework, Next: connector-net-website-config, Prev: connector-net-visual-studio-dropping-database-objects, Up: connector-net-visual-studio 21.2.3.14 Using the ADO.NET Entity Framework ............................................ Connector/NET 6.0 introduced support for the ADO.NET Entity Framework. ADO.NET Entity Framework was included with .NET Framework 3.5 Service Pack 1, and Visual Studio 2008 Service Pack 1. ADO.NET Entity Framework was released on 11th August 2008. ADO.NET Entity Framework provides an Object Relational Mapping (ORM) service, mapping the relational database schema to objects. The ADO.NET Entity Framework defines several layers, these can be summarized as: * *Logical* - this layer defines the relational data and is defined by the Store Schema Definition Language (SSDL). * *Conceptual* - this layer defines the .NET classes and is defined by the Conceptual Schema Definition Language (CSDL) * *Mapping* - this layer defines the mapping from .NET classes to relational tables and associations, and is defined by Mapping Specification Language (MSL). Connector/NET integrates with Visual Studio 2008 to provide a range of helpful tools to assist the developer. A full treatment of ADO.NET Entity Framework is beyond the scope of this manual. You are encouraged to review the Microsoft ADO.NET Entity Framework documentation (http://msdn.microsoft.com/en-us/library/aa697427(VS.80).aspx). Tutorials on getting started with ADO.NET Entity Framework are available. See *Note connector-net-tutorials-entity-framework-winform-data-source:: and *Note connector-net-tutorials-entity-framework-databinding-linq-entities::.  File: manual.info, Node: connector-net-website-config, Next: connector-net-sql-editor, Prev: connector-net-visual-studio-entity-framework, Up: connector-net-visual-studio 21.2.3.15 MySQL Website Configuration Tool .......................................... MySQL Connector/NET 6.1 introduced the MySQL Website Configuration Tool. This is a facility available in Visual Studio that enables you to configure the Membership, Role, Session State and Profile Provider, without having to resort to editing configuration files. You simply run the tool, set your configuration options, and the tool will modify your `web.config' file accordingly. The MySQL Website Configuration Tool appears as a small icon on the Solution Explorer toolbar in Visual Studio, as show by the following screenshot: FIGURE GOES HERE: MySQL Website Configuration Tool Clicking the Website Configuration Tool icon launches the wizard and displays the first screen: FIGURE GOES HERE: MySQL Website Configuration Tool - Membership This allows you to enable use of the MySQL Membership Provider. Simply click the check box to enable this. You can now enter the name of the application that you are creating the configuration for. You can also enter a description for the application. You can then click the `Edit...' button to launch the Connection String Editor: FIGURE GOES HERE: MySQL Website Configuration Tool - Connection String Editor Note that if you have already defined a connection string for the providers manually in `web.config', or previously using the tool, this will be automatically loaded and displayed, and can then be modified in this dialog. You can also ensure that the necessary schema are created automatically for you by selecting the Autogenerate Schema check box. These schema are used to store membership information. The database used to storage is the one specified in the connection string. You can also ensure that exceptions generated by the application will be written to the event log by selecting the `Write exceptions to event log' check box. Clicking the `Advanced...' button launches a dialog that enables you to set Membership Options. These options dictate such variables as password length required when a user signs up, whether the password is encrypted and whether the user can reset their password or not. FIGURE GOES HERE: MySQL Website Configuration Tool - Advanced Options Once information has been set up as required for configuration of the Membership Provider the `Next' button can be clicked to display the Roles Provider screen: FIGURE GOES HERE: MySQL Website Configuration Tool - Roles Again the connection string can be edited, a description added and Autogenerate Schema can be enabled before clicking `Next' to go to the Profiles Provider screen: FIGURE GOES HERE: MySQL Website Configuration Tool - Profiles This screen display similar options to the previous screens. Click `Next' to proceed to the Session State configuration page: FIGURE GOES HERE: MySQL Website Configuration Tool - Session State Once you have set up the Session State Provider as required, click `Finish' to exit the wizard. At this point it is necessary to select the Authentication Type to From Internet. This can be done by launching the ASP.NET Configuration Tool, and selecting the Security tab. Click the Select authentication type link and ensure that the From the internet radio button is selected. You can now examine the database you created to store membership information. All the necessary tables will have been created for you: FIGURE GOES HERE: MySQL Website Configuration Tool - Tables  File: manual.info, Node: connector-net-sql-editor, Next: connector-net-ddl-t4-ef, Prev: connector-net-website-config, Up: connector-net-visual-studio 21.2.3.16 MySQL SQL Editor .......................... MySQL Connector/NET 6.3.2 introduced a new MySQL SQL Editor. The easiest way to invoke the editor is by selecting the `New', `File' menu item from the Visual Studio main menu. This displays the `New File' dialog: FIGURE GOES HERE: MySQL SQL Editor - New File From the `New File' dialog select the MySQL template, and then double-click the `MySQL SQL Script' document, or click the `Open' button. The MySQL SQL Editor will be displayed. You can now enter SQL code as required, or connect to a MySQL server. Click the `Connect to MySQL' button in the MySQL SQL Editor toolbar. You can enter the connection details into the `Connect to MySQL' dialog that is displayed. You can enter the server name, user id, password and database to connect to, or click the `Advanced' button to select other connection string options. Click the `Connect' button to connect to the MySQL server. It is now possible to execute your SQL code against the server by clicking the `Run SQL' button on the toolbar. FIGURE GOES HERE: MySQL SQL Editor - Query The results from any queries are displayed on the `Results' tab. Any errors are displayed on the `Messages' tab.  File: manual.info, Node: connector-net-ddl-t4-ef, Prev: connector-net-sql-editor, Up: connector-net-visual-studio 21.2.3.17 DDL T4 Template Macro ............................... MySQL Connector/NET 6.3 introduced the ability to convert an Entity Framework model to MySQL DDL code. Starting with a blank model, an entity model can be developed in Visual Studio's designer. Once the model has been created, the model's properties can be selected, and in the Database Script Generation category of the model's properties, the property `DDL Generation' can be found. The value `SSDLToMySQL.tt(VS)' can then be selected from the drop-down listbox. FIGURE GOES HERE: DDL T4 Template Macro - Model Properties Right-clicking the model design area will display a context-sensitive menu. Selecting `Generate Database from Model' from the menu will display the `Generate Database Wizard'. The wizard can then be used to generate MySQL DDL code. FIGURE GOES HERE: DDL T4 Template Macro - Generate Database Wizard  File: manual.info, Node: connector-net-tutorials, Next: connector-net-programming, Prev: connector-net-visual-studio, Up: connector-net 21.2.4 Connector/NET Tutorials ------------------------------ * Menu: * connector-net-tutorials-intro:: Tutorial: An Introduction to Connector/NET Programming * connector-net-tutorials-asp-roles:: Tutorial: MySQL Connector/NET ASP.NET Membership and Role Provider * connector-net-tutorials-asp-provider-session-state:: Tutorial: MySQL Connector/NET ASP.NET Session State Provider * connector-net-tutorials-asp-provider-profile:: Tutorial: MySQL Connector/NET ASP.NET Profile Provider * connector-net-tutorials-entity-framework-winform-data-source:: Tutorial: Using an Entity Framework Entity as a Windows Forms Data Source * connector-net-tutorials-entity-framework-databinding-linq-entities:: Tutorial: Databinding in ASP.NET using LINQ on Entities * connector-net-tutorials-ssl:: Tutorial: Using SSL with MySQL Connector/NET * connector-net-tutorials-mysqlscript:: Tutorial: Using MySqlScript * connector-net-tutorials-efmodel-ddl:: Tutorial: Generating MySQL DDL from an Entity Framework Model  File: manual.info, Node: connector-net-tutorials-intro, Next: connector-net-tutorials-asp-roles, Prev: connector-net-tutorials, Up: connector-net-tutorials 21.2.4.1 Tutorial: An Introduction to Connector/NET Programming ............................................................... * Menu: * connector-net-tutorials-connection:: The MySqlConnection Object * connector-net-tutorials-sql-command:: The MySqlCommand Object * connector-net-tutorials-data-adapter:: Working with Decoupled Data * connector-net-tutorials-parameters:: Working with Parameters * connector-net-tutorials-stored-procedures:: Working with Stored Procedures This section provides a gentle introduction to programming with Connector/NET. The example code is written in C#, and is designed to work on both Microsoft .NET Framework and Mono. This tutorial is designed to get you up and running with Connector/NET as quickly as possible, it does not go into detail on any particular topic. However, the following sections of this manual describe each of the topics introduced in this tutorial in more detail. In this tutorial you are encouraged to type in and run the code, modifying it as required for your setup. This tutorial assumes you have MySQL and Connector/NET already installed. It also assumes that you have installed the World example database, which can be downloaded from the MySQL Documentation page (http://dev.mysql.com/doc/index-other.html). You can also find details on how to install the database on the same page. *Note*: Before compiling the example code make sure that you have added References to your project as required. The References required are `System', `System.Data' and `MySql.Data'.  File: manual.info, Node: connector-net-tutorials-connection, Next: connector-net-tutorials-sql-command, Prev: connector-net-tutorials-intro, Up: connector-net-tutorials-intro 21.2.4.2 The MySqlConnection Object ................................... For your Connector/NET application to connect to a MySQL database it needs to establish a connection. This is achieved through the use of a `MySqlConnection' object. The MySqlConnection constructor takes a connection string as one of its parameters. The connection string provides necessary information to make the connection to the MySQL database. The connection string is discussed more fully in *Note connector-net-programming-connecting::. A reference containing a list of supported connection string options can also be found in *Note connector-net-connection-options::. The following code shows how to create a connection object. using System; using System.Data; using MySql.Data; using MySql.Data.MySqlClient; public class Tutorial1 { public static void Main() { string connStr = "server=localhost;user=root;database=world;port=3306;password=******;"; MySqlConnection conn = new MySqlConnection(connStr); try { Console.WriteLine("Connecting to MySQL..."); conn.Open(); // Perform database operations } catch (Exception ex) { Console.WriteLine(ex.ToString()); } conn.Close(); Console.WriteLine("Done."); } } When the `MySqlConnection' constructor is invoked it returns a connection object, which is used for subsequent database operations. The first operation in this example is to open the connection. This needs to be done before further operations take place. Before the application exits the connection to the database needs to be closed by calling `Close' on the connection object. Sometimes an attempt to perform an `Open' on a connection object can fail, this will generate an exception that can be handled using standard exception handling code. In this section you have learned how to create a connection to a MySQL database, and open and close the corresponding connection object.  File: manual.info, Node: connector-net-tutorials-sql-command, Next: connector-net-tutorials-data-adapter, Prev: connector-net-tutorials-connection, Up: connector-net-tutorials-intro 21.2.4.3 The MySqlCommand Object ................................ Once a connection has been established with the MySQL database, the next step is do carry out the desired database operations. This can be achieved through the use of the `MySqlCommand' object. You will see how to create a `MySqlCommand' object. Once it has been created there are three main methods of interest that you can call: * *ExecuteReader* - used to query the database. Results are usually returned in a `MySqlDataReader' object, created by `ExecuteReader'. * *ExecuteNonQuery* - used to insert and delete data. * *ExecuteScalar* - used to return a single value. Once a `MySqlCommand' object has been created, you will call one of the above methods on it to carry out a database operation, such as perform a query. The results are usually returned into a `MySqlDataReader' object, and then processed, for example the results might be displayed. The following code demonstrates how this could be done. using System; using System.Data; using MySql.Data; using MySql.Data.MySqlClient; public class Tutorial2 { public static void Main() { string connStr = "server=localhost;user=root;database=world;port=3306;password=******;"; MySqlConnection conn = new MySqlConnection(connStr); try { Console.WriteLine("Connecting to MySQL..."); conn.Open(); string sql = "SELECT Name, HeadOfState FROM Country WHERE Continent='Oceania'"; MySqlCommand cmd = new MySqlCommand(sql, conn); MySqlDataReader rdr = cmd.ExecuteReader(); while (rdr.Read()) { Console.WriteLine(rdr[0]+" -- "+rdr[1]); } rdr.Close(); } catch (Exception ex) { Console.WriteLine(ex.ToString()); } conn.Close(); Console.WriteLine("Done."); } } When a connection has been created and opened, the code then creates a `MySqlCommand' object. Note that the SQL query to be executed is passed to the `MySqlCommand' constructor. The `ExecuteReader' method is then used to generate a `MySqlReader' object. The `MySqlReader' object contains the results generated by the SQL executed on the command object. Once the results have been obtained in a `MySqlReader' object, the results can be processed. In this case the information is simply printed out as part of a `while' loop. Finally, the `MySqlReader' object is disposed of by running its `Close' method on it. In the next example you will see how to use the `ExecuteNonQuery' method. The procedure for performing an `ExecuteNonQuery' method call is simpler, as there is no need to create an object to store results. This is because `ExecuteNonQuery' is only used for inserting, updating and deleting data. The following example illustrates a simple update to the Country table: using System; using System.Data; using MySql.Data; using MySql.Data.MySqlClient; public class Tutorial3 { public static void Main() { string connStr = "server=localhost;user=root;database=world;port=3306;password=******;"; MySqlConnection conn = new MySqlConnection(connStr); try { Console.WriteLine("Connecting to MySQL..."); conn.Open(); string sql = "INSERT INTO Country (Name, HeadOfState, Continent) VALUES ('Disneyland','Mickey Mouse', 'North America')"; MySqlCommand cmd = new MySqlCommand(sql, conn); cmd.ExecuteNonQuery(); } catch (Exception ex) { Console.WriteLine(ex.ToString()); } conn.Close(); Console.WriteLine("Done."); } } The query is constructed, the command object created and the `ExecuteNonQuery' method called on the command object. You can access your MySQL database with the MySQL Client program and verify that the update was carried out correctly. Finally, you will see how the `ExecuteScalar' method can be used to return a single value. Again, this is straightforward, as a `MySqlDataReader' object is not required to store results, a simple variable will do. The following code illustrates how to use `ExecuteScalar': using System; using System.Data; using MySql.Data; using MySql.Data.MySqlClient; public class Tutorial4 { public static void Main() { string connStr = "server=localhost;user=root;database=world;port=3306;password=******;"; MySqlConnection conn = new MySqlConnection(connStr); try { Console.WriteLine("Connecting to MySQL..."); conn.Open(); string sql = "SELECT COUNT(*) FROM Country"; MySqlCommand cmd = new MySqlCommand(sql, conn); object result = cmd.ExecuteScalar(); if (result != null) { int r = Convert.ToInt32(result); Console.WriteLine("Number of countries in the World database is: " + r); } } catch (Exception ex) { Console.WriteLine(ex.ToString()); } conn.Close(); Console.WriteLine("Done."); } } This example uses a simple query to count the rows in the Country table. The result is obtained by calling `ExecuteScalar' on the command object.  File: manual.info, Node: connector-net-tutorials-data-adapter, Next: connector-net-tutorials-parameters, Prev: connector-net-tutorials-sql-command, Up: connector-net-tutorials-intro 21.2.4.4 Working with Decoupled Data .................................... Previously, when using MySqlDataReader, the connection to the database was continually maintained, unless explicitly closed. It is also possible to work in a manner where a connection is only established when needed. For example, in this mode, a connection could be established to read a chunk of data, the data could then be modified by the application as required. A connection could then be reestablished only if and when the application needs to write data back to the database. This decouples the working data set from the database. This decouple mode of working with data is supported by Connector/NET. There are several parts involved in allowing this method to work: * *Data Set* - The Data Set is the area in which data is loaded to read or modify it. A `DataSet' object is instantiated, which can store multiple tables of data. * *Data Adapter* - The Data Adapter is the interface between the Data Set and the database itself. The Data Adapter is responsible for efficiently managing connections to the database, opening and closing them as required. The Data Adapter is created by instantiating an object of the `MySqlDataAdapter' class. The `MySqlDataAdapter' object has two main methods: `Fill' which reads data into the Data Set, and `Update', which writes data from the Data Set to the database. * *Command Builder* - The Command Builder is a support object. The Command Builder works in conjunction with the Data Adapter. When a `MySqlDataAdapter' object is created it is typically given an initial SELECT statement. From this SELECT statement the Command Builder can work out the corresponding INSERT, UPDATE and DELETE statements that would be required should the database need to be updated. To create the Command Builder an object of the class `MySqlCommandBuilder' is created. Each of these classes will now be discussed in more detail. *Instantiating a DataSet object* A `DataSet' object can be created simply, as shown in the following example code snippet: DataSet dsCountry; ... dsCountry = new DataSet(); Although this creates the `DataSet' object it has not yet filled it with data. For that a Data Adapter is required. *Instantiating a MySqlDataAdapter object* The `MySqlDataAdapter' can be created as illustrated by the following example: MySqlDataAdapter daCountry; ... string sql = "SELECT Code, Name, HeadOfState FROM Country WHERE Continent='North America'"; daCountry = new MySqlDataAdapter (sql, conn); Note, the `MySqlDataAdapter' is given the SQL specifying the data you wish to work with. *Instantiating a MySqlCommandBuilder object* Once the `MySqlDataAdapter' has been created, it is necessary to generate the additional statements required for inserting, updating and deleting data. There are several ways to do this, but in this tutorial you will see how this can most easily be done with `MySqlCommandBuilder'. The following code snippet illustrates how this is done: MySqlCommandBuilder cb = new MySqlCommandBuilder(daCountry); Note that the `MySqlDataAdapter' object is passed as a parameter to the command builder. *Filling the Data Set* To do anything useful with the data from your database, you need to load it into a Data Set. This is one of the jobs of the `MySqlDataAdapter' object, and is carried out with its `Fill' method. The following example code illustrates this: DataSet dsCountry; ... dsCountry = new DataSet(); ... daCountry.Fill(dsCountry, "Country"); Note the `Fill' method is a `MySqlDataAdapter' method, the Data Adapter knows how to establish a connec tion with the database and retrieve the required data, and then populates the Data Set when the `Fill' method is called. The second parameter `Country' is the table in the Data Set to update. *Updating the Data Set* The data in the Data Set can now be manipulated by the application as required. At some point, changes to data will need to be written back to the database. This is achieved through a `MySqlDataAdapter' method, the `Update' method. daCountry.Update(dsCountry, "Country"); Again, the Data Set and the table within the Data Set to update are specified. *Working Example* The interactions between the `DataSet', `MySqlDataAdapter' and `MySqlCommandBuilder' classes can be a little confusing, so their operation can perhaps be best illustrated by working code. In this example, data from the World database is read into a Data Grid View control. Here, the data can be viewed and changed before clicking an update button. The update button then activates code to write changes back to the database. The code uses the principles explained above. The application was built using the Microsoft Visual Studio to place and create the user interface controls, but the main code that uses the key classes described above is shown below, and is portable. using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Linq; using System.Text; using System.Windows.Forms; using MySql.Data; using MySql.Data.MySqlClient; namespace WindowsFormsApplication5 { public partial class Form1 : Form { MySqlDataAdapter daCountry; DataSet dsCountry; public Form1() { InitializeComponent(); } private void Form1_Load(object sender, EventArgs e) { string connStr = "server=localhost;user=root;database=world;port=3306;password=******;"; MySqlConnection conn = new MySqlConnection(connStr); try { label2.Text = "Connecting to MySQL..."; string sql = "SELECT Code, Name, HeadOfState FROM Country WHERE Continent='North America'"; daCountry = new MySqlDataAdapter (sql, conn); MySqlCommandBuilder cb = new MySqlCommandBuilder(daCountry); dsCountry = new DataSet(); daCountry.Fill(dsCountry, "Country"); dataGridView1.DataSource = dsCountry; dataGridView1.DataMember = "Country"; } catch (Exception ex) { label2.Text = ex.ToString(); } } private void button1_Click(object sender, EventArgs e) { daCountry.Update(dsCountry, "Country"); label2.Text = "MySQL Database Updated!"; } } } The application running is shown below: FIGURE GOES HERE: World Database Application  File: manual.info, Node: connector-net-tutorials-parameters, Next: connector-net-tutorials-stored-procedures, Prev: connector-net-tutorials-data-adapter, Up: connector-net-tutorials-intro 21.2.4.5 Working with Parameters ................................ This part of the tutorial shows you how to use parameters in your Connector/NET application. Although it is possible to build SQL query strings directly from user input, this is not advisable as it does not prevent erroneous or malicious information being entered. It is safer to use parameters as they will be processed as field data only. For example, imagine the following query was constructed from user input: string sql = "SELECT Name, HeadOfState FROM Country WHERE Continent = "+user_continent; If the string `user_continent' came from a Text Box control, there would potentially be no control over the string entered by the user. The user could enter a string that generates a run time error, or in the worst case actually harms the system. When using parameters it is not possible to do this because a parameter is only ever treated as a field parameter, rather than an arbitrary piece of SQL code. The same query written user a parameter for user input would be: string sql = "SELECT Name, HeadOfState FROM Country WHERE Continent = @Continent"; Note that the parameter is preceded by an '@' symbol to indicate it is to be treated as a parameter. As well as marking the position of the parameter in the query string, it is necessary to add a parameter to the Command object. This is illustrated by the following code snippet: cmd.Parameters.AddWithValue("@Continent", "North America"); In this example the string "North America" is supplied as the parameter value statically, but in a more practical example it would come from a user input control. A further example illustrates the complete process: using System; using System.Data; using MySql.Data; using MySql.Data.MySqlClient; public class Tutorial5 { public static void Main() { string connStr = "server=localhost;user=root;database=world;port=3306;password=******;"; MySqlConnection conn = new MySqlConnection(connStr); try { Console.WriteLine("Connecting to MySQL..."); conn.Open(); string sql = "SELECT Name, HeadOfState FROM Country WHERE Continent=@Continent"; MySqlCommand cmd = new MySqlCommand(sql, conn); Console.WriteLine("Enter a continent e.g. 'North America', 'Europe': "); string user_input = Console.ReadLine(); cmd.Parameters.AddWithValue("@Continent", user_input); MySqlDataReader rdr = cmd.ExecuteReader(); while (rdr.Read()) { Console.WriteLine(rdr["Name"]+" --- "+rdr["HeadOfState"]); } rdr.Close(); } catch (Exception ex) { Console.WriteLine(ex.ToString()); } conn.Close(); Console.WriteLine("Done."); } } In this part of the tutorial you have see how to use parameters to make your code more secure.  File: manual.info, Node: connector-net-tutorials-stored-procedures, Prev: connector-net-tutorials-parameters, Up: connector-net-tutorials-intro 21.2.4.6 Working with Stored Procedures ....................................... In this section you will see how to work with Stored Procedures. This section assumes you have a basic understanding of what a Stored Procedure is, and how to create one. For the purposes of this tutorial, you will create a simple Stored Procedure to see how it can be called from Connector/NET. In the MySQL Client program, connect to the World database and enter the following Stored Procedure: DELIMITER // CREATE PROCEDURE country_hos (IN con CHAR(20)) BEGIN SELECT Name, HeadOfState FROM Country WHERE Continent = con; END // DELIMITER ; Test the Stored Procedure works as expected by typing the following into the MySQL Client program: CALL country_hos('Europe'); Note that The Stored Routine takes a single parameter, which is the continent you wish to restrict your search to. Having confirmed that the Stored Procedure is present and correct you can now move on to seeing how it can be accessed from Connector/NET. Calling a Stored Procedure from your Connector/NET application is similar to techniques you have seen earlier in this tutorial. A `MySqlCommand' object is created, but rather than taking an SQL query as a parameter it takes the name of the Stored Procedure to call. The `MySqlCommand' object also needs to be set to the type of Stored Procedure. This is illustrated by the following code snippet: string rtn = "country_hos"; MySqlCommand cmd = new MySqlCommand(rtn, conn); cmd.CommandType = CommandType.StoredProcedure; In this case you also need to pass a parameter to the Stored Procedure. This can be achieved using the techniques seen in the previous section on parameters, *Note connector-net-tutorials-parameters::. This is shown in the following code snippet: cmd.Parameters.AddWithValue("@con", "Europe"); The value of the parameter `@con' could more realistically have come from a user input control, but for simplicity it is set as a static string in this example. At this point everything is set up and all that now needs to be done is to call the routine. This can be achieved using techniques also learned in earlier sections, but in this case the `ExecuteReader' method of the `MySqlCommand' object is used. Complete working code for the Stored Procedure example is shown below: using System; using System.Data; using MySql.Data; using MySql.Data.MySqlClient; public class Tutorial6 { public static void Main() { string connStr = "server=localhost;user=root;database=world;port=3306;password=******;"; MySqlConnection conn = new MySqlConnection(connStr); try { Console.WriteLine("Connecting to MySQL..."); conn.Open(); string rtn = "country_hos"; MySqlCommand cmd = new MySqlCommand(rtn, conn); cmd.CommandType = CommandType.StoredProcedure; cmd.Parameters.AddWithValue("@con", "Europe"); MySqlDataReader rdr = cmd.ExecuteReader(); while (rdr.Read()) { Console.WriteLine(rdr[0] + " --- " + rdr[1]); } rdr.Close(); } catch (Exception ex) { Console.WriteLine(ex.ToString()); } conn.Close(); Console.WriteLine("Done."); } } In this section you have seen how to call a Stored Procedure from Connector/NET. For the moment, this concludes our introductory tutorial on programming with Connector/NET.  File: manual.info, Node: connector-net-tutorials-asp-roles, Next: connector-net-tutorials-asp-provider-session-state, Prev: connector-net-tutorials-intro, Up: connector-net-tutorials 21.2.4.7 Tutorial: MySQL Connector/NET ASP.NET Membership and Role Provider ........................................................................... Many web sites feature the facility for the user to create a user account. They can then log into the web site and enjoy a personalized experience. This requires that the developer creates database tables to store user information, along with code to gather and process this data. This represents a burden on the developer, and there is the possibility for security issues to creep into the developed code. However, ASP.NET 2.0 introduced the Membership system. This system is designed around the concept of Membership, Profile and Role Providers, which together provide all of the functionality to implement a user system, that previously would have to have been created by the developer from scratch. Currently, MySQL Connector/NET provides Membership, Role, Profile and Session State Providers. This tutorial shows you how to set up your ASP.NET web application to use the MySQL Connector/NET Membership and Role Providers. It assumes that you have MySQL Server installed, along with MySQL Connector/NET and Microsoft Visual Studio. This tutorial was tested with MySQL Connector/NET 6.0.4 and Microsoft Visual Studio 2008 Professional Edition. It is recommended you use 6.0.4 or above for this tutorial. 1. Create a new database in the MySQL Server using the MySQL Command Line Client program (`mysql'), or other suitable tool. It does not matter what name is used for the database, but it should be noted down so that it can be specified in the connection string constructed later in this tutorial. This database will contain the tables, automatically created for you later, used to store data about users and roles. 2. Create a new ASP.NET Web Site in Visual Studio. If you are not sure how to do this, refer to the following tutorial: *Note connector-net-tutorials-entity-framework-databinding-linq-entities::, which demonstrates how to create a simple ASP.NET web site. 3. Add References to `MySql.Data' and `MySql.Web' to the web site project. 4. Locate the `machine.config' file on your system, which is the configuration file for the .NET Framework. 5. Search the `machine.config' file to find the membership provider `MySQLMembershipProvider'. 6. Add the attribute `autogenerateschema="true"'. The appropriate section should now resemble the following (note: for the sake of brevity some information has been excluded): Note that the name for the connection string to be used to connect to the server that contains the membership database is `LocalMySqlServer'. The `autogenerateschema="true"' attribute will cause MySQL Connector/NET to silently create, or upgrade, the schema on the database server, to contain the required tables for storing membership information. 7. It is now necessary to create the connection string referenced in the previous step. Load the web site's `web.config' file into Visual Studio. 8. Locate the section marked `'. Add the following connection string information: The database specified is the one created in the first step. You could alternatively have used an existing database. 9. At this point build the solution to ensure no errors are present. This can be done by selecting `Build', `Build Solution' from the main menu, or pressing `F6'. 10. ASP.NET supports the concept of locally and remotely authenticated users. With local authentication the user is validated using their Windows credentials when they attempt to access the web site. This can be useful in an Intranet environment. With remote authentication a user is prompted for their login details when accessing the web site, and these credentials are checked against the membership information stored in a database server such as MySQL Server. You will now see how to choose this form of authentication. Start the ASP.NET Web Site Administration Tool. This can be done quickly by clicking the small hammer/Earth icon in the Solution Explorer. You can also launch this tool by selecting `Website', `ASP.NET Configuration' from the main menu. 11. In the ASP.NET Web Site Administration Tool click the `Security' tab. 12. Now click the `User Authentication Type' link. 13. Select the `From the internet' radio button. The web site will now need to provide a form to allow the user to enter their login details. These will be checked against membership information stored in the MySQL database. FIGURE GOES HERE: Authentication Type 14. You now need to specify the Role and Membership Provider to be used. Click the `Provider' tab. 15. Click the `Select a different provider for each feature (advanced)' link. 16. Now select the `MySQLMembershipProvider' and the `MySQLRoleProvider' radio buttons. FIGURE GOES HERE: Select Membership and Role Provider 17. In Visual Studio rebuild the solution by selecting `Build', `Rebuild Solution' from the main menu. 18. Check that the necessary schema has been created. This can be achieved using the MySQL Command Line Client program. FIGURE GOES HERE: Membership and Role Provider Tables 19. Assuming all is present and correct you can now create users and roles for your web application. The easiest way to do this is with the ASP.NET Web Site Administration Tool. However, many web applications contain their own modules for creating roles and users. For simplicity the ASP.NET Web Site Administration Tool will be used in this tutorial. 20. In the ASP.NET Web Site Administration Tool, click the `Security' tab. Now that both the Membership and Role Provider are enabled you will see links for creating roles and users. Click the `Create or Manage Roles' link. FIGURE GOES HERE: Security Tab 21. You can now enter the name of a new Role and click `Add Role' to create the new Role. Create new Roles as required. 22. Click the `Back' button. 23. Click the `Create User' link. You can now fill in information about the user to be created, and also allocate that user to one or more Roles. FIGURE GOES HERE: Create User 24. Using the MySQL Command Line Client program you can check that your database has been correctly populated with the Membership and Role data. FIGURE GOES HERE: Membership and Roles Table Contents In this tutorial you have seen how to set up the MySQL Connector/NET Membership and Role Providers for use in your ASP.NET web application.  File: manual.info, Node: connector-net-tutorials-asp-provider-session-state, Next: connector-net-tutorials-asp-provider-profile, Prev: connector-net-tutorials-asp-roles, Up: connector-net-tutorials 21.2.4.8 Tutorial: MySQL Connector/NET ASP.NET Session State Provider ..................................................................... MySQL Connector/NET from version 6.1 has included a MySQL Session State Provider. This provider enables you to store session state in a MySQL database. The following tutorial shows you how to prepare to use the MySQL Session State Provider, and then store session data into the MySQL database. This tutorial uses Microsoft Visual Studio 2008 Professional Edition, MySQL Connector/NET 6.1.1 and MySQL Server 5.1. This tutorial also assumes you have created an empty database, for example `test', where you will store session data. You could do this using the MySQL Command Line Client tool. 1. In Visual Studio create a new ASP.NET web site. If you are not sure how to do this refer to the tutorial *Note connector-net-tutorials-entity-framework-databinding-linq-entities:: which demonstrates how to do this. 2. Launch the MySQL MySQL Website Configuration tool. Due to a bug in 6.1.1 this may not appear unless you are connected to a server in the Server Explorer. If you are unfamiliar with the MySQL Website Configuration tool it is suggested that you first work through the following tutorial *Note connector-net-website-config::. 3. Navigate through the wizard to the Session State page. Make sure the check box `Use MySQL to manage my ASP.NET session data' is selected. 4. On the same page configure the connection string to the database that will contain your session data. This database can be empty as MySQL Connector/NET will create the schema required to store session data. 5. Ensure that the check box `Autogenerate Schema' is selected so that MySQL Connector/NET will create the schema in your database to store the session data correctly. 6. Enter the name of your application. 7. Click `Finish'. The MySQL Website Configuration tool will now update your application's `web.config' file with information about the connection string and default providers to be used. In this case we have selected the MySQL Session State Provider. At this point you are ready to use the MySQL database to store session data. To test that the set up has worked you can write a simple program that uses session variables. 1. Open `Default.aspx.cs'. In the Page_Load method add the following code: Session["SessionVariable1"] = "Test string"; 2. Build your solution. 3. Run the solution (without debugging). When the application runs, the provider will autogenerate tables required in the database you chose when setting up the application. 4. Check that the schema was in fact created. Using the MySQL Command Line Client use the target database and then type `SHOW TABLES;'. You will see that MySQL Connector/NET has created the required schema automatically, as we selected this to happen in the MySQL Website Configuration tool. 5. Now view the contents of these tables by typing `SELECT * FROM my_aspnet_sessions;' in the MySQL Command Line Client. This will display the session data our application used. Note that this is stored in binary format so some data may not display as expected. At this point you have installed the Session State Provider and carried out a preliminary test of the installation. You will now work a bit more with the Session State Provider. In this part of the tutorial you will set and retrieve a session variable. You can work with your existing project. 1. Select the `Default.aspx' and switch to Design View. Add a text box and three buttons. Change the text property for the buttons to `Store Session Variable', `Clear Textbox', and `Show Session Variable'. These will be `Button1', `Button2' and `Button3' respectively. Build your solution to ensure that no errors have been introduced. 2. Still in the Design View, double-click `Button1'. Now to the `Button1_Click' event handler add code some the handler resembles the following: protected void Button1_Click(object sender, EventArgs e) { Session["SessionString"] = TextBox1.Text; } You have created a new Session variable accessed using the key `SessionString'. This will be set to the text that was entered into the text box when `Button1' is clicked. 3. In Design View double-click `Button2' to add its click event handler. This button needs to clear text from the text box. The code to do this is as follows: protected void Button2_Click(object sender, EventArgs e) { TextBox1.Text = ""; } The code simply assigns an empty string to the `Text' property of the text box. 4. In the Design View double-click `Button3' and modify the click handler as follows: protected void Button3_Click(object sender, EventArgs e) { TextBox1.Text = (String)Session["SessionString"]; } This will retrieve the session string and display it in the text box. 5. Now modify the `Page_Load' method as follows: protected void Page_Load(object sender, EventArgs e) { if (!IsPostBack) { TextBox1.Text = "Enter some text"; } } This ensures that when the page loads the text box `Text' property is reset. 6. Ensure that the solution is saved and then rebuild the solution. 7. Run the solution without debugging. 8. The form will be displayed. Enter some text into the text box. Now click `Store Session Variable'. At this point you have stored the string in a session variable. 9. Now click `Clear Text' to clear the text box. 10. Now click `Show Session Variable' to retrieve and display the session variable. 11. Refresh the page to destroy the form and display a new form. 12. Click `Show Session Variable' the text box will display the stored session variable, demonstrating that the refreshing the page does not destroy the session variable. This illustrates that the session state data is not destroyed when a page is reloaded.  File: manual.info, Node: connector-net-tutorials-asp-provider-profile, Next: connector-net-tutorials-entity-framework-winform-data-source, Prev: connector-net-tutorials-asp-provider-session-state, Up: connector-net-tutorials 21.2.4.9 Tutorial: MySQL Connector/NET ASP.NET Profile Provider ............................................................... This tutorial shows you how to use the MySQL Profile Provider to store user profile information in a MySQL database. The tutorial uses MySQL Connector/NET 6.1.1, MySQL Server 5.1 and Microsoft Visual Studio 2008 Professional Edition. Many modern web sites allow the user to create a personal profile. This requires a significant amount of code, but ASP.NET reduces this considerable by including the functionality in its Profile classes. The Profile Provider provides an abstraction between these classes and a data source. The MySQL Profile Provider enables profile data to be stored in a MySQL database. This enables the profile properties to be written to a persistent store, and be retrieved when required. The Profile Provider also enables profile data to be managed effectively, for example it enables profiles that have not been accessed since a specific date to be deleted. The following steps show you how you can select the MySQL Profile Provider. 1. Create a new ASP.NET web project. 2. Select the MySQL Website Configuration tool. Due to a bug in 6.1.1 you may have to first connect to a server in Server Explorer before the tool's icon will display in the toolbar of the Solution Explorer. 3. In the MySQL Website Configuration tool navigate through the tool to the Profiles page. 4. Select the `Use MySQL to manage my profiles' check box. 5. Select the `Autogenerate Schema' check box. 6. Click the `Edit...' button and configure a connection string for the database that will be used to store user profile information. 7. Navigate to the last page of the tool and click `Finish' to save your changes and exit the tool. At this point you are now ready to start using the MySQL Profile Provider. With the following steps you can carry out a preliminary test of your installation. 1. Open your `web.config' file. 2. Add a simple profile such as the following: ... ... Note that `anonymousIdentification' has been set to true. This enables users who have not been authenticated to use profiles. They are identified by a GUID in a cookie rather than by user name. Now that the simple profile has been defined in `web.config', the next step is to write some code to test the profile. 1. In Design View design a simple page with the following controls: FIGURE GOES HERE: Simple Profile Application These will allow the user to enter some profile information. The user can also use the buttons to save their profile, clear the page, and restore their profile data. 2. In the Code View add code as follows: ... protected void Page_Load(object sender, EventArgs e) { if (!IsPostBack) { TextBox1.Text = Profile.Name; TextBox2.Text = Profile.Age.ToString(); Label1.Text = Profile.UI.Color; } } // Store Profile protected void Button1_Click(object sender, EventArgs e) { Profile.Name = TextBox1.Text; Profile.Age = UInt16.Parse(TextBox2.Text); } // Clear Form protected void Button2_Click(object sender, EventArgs e) { TextBox1.Text = ""; TextBox2.Text = ""; Label1.Text = ""; } // Retrieve Profile protected void Button3_Click(object sender, EventArgs e) { TextBox1.Text = Profile.Name; TextBox2.Text = Profile.Age.ToString(); Label1.Text = Profile.UI.Color; } protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e) { Profile.UI.Color = DropDownList1.SelectedValue; } ... 3. Save all files and build the solution to check that no errors have been introduced. 4. Run the application. 5. Enter your name, age and select a color from the listbox. Now store this information in your profile by clicking `Store Profile'. Note that if you do not select a color from the listbox your profile will use the default color `Blue' that was specified in the `web.config' file. 6. Click `Clear Form' to clear text from the textboxes and the label that displays your chosen color. 7. Now click `Retrieve Profile' to restore your profile data from the MySQL database. 8. Now exit the browser to terminate the application. 9. Run the application again. Note that when the page loads your profile information is restored from the MySQL database. In this tutorial you have seen how to using the MySQL Profile Provider with MySQL Connector/NET.  File: manual.info, Node: connector-net-tutorials-entity-framework-winform-data-source, Next: connector-net-tutorials-entity-framework-databinding-linq-entities, Prev: connector-net-tutorials-asp-provider-profile, Up: connector-net-tutorials 21.2.4.10 Tutorial: Using an Entity Framework Entity as a Windows Forms Data Source ................................................................................... In this tutorial you will learn how to create a Windows Forms Data Source from an Entity in an Entity Data Model. This tutorial assumes that you have installed the World example database, which can be downloaded from the MySQL Documentation page (http://dev.mysql.com/doc/index-other.html). You can also find details on how to install the database on the same page. It will also be convenient for you to create a connection to the World database after it is installed. For instructions on how to do this see *Note connector-net-visual-studio-making-a-connection::. *Creating a new Windows Forms application* The first step is to create a new Windows Forms application. 1. In Visual Studio, select `File', `New', `Project' from the main menu. 2. Choose the `Windows Forms Application' installed template. Click `OK'. The solution is created. *Adding an Entity Data Model* You will now add an Entity Data Model to your solution. 1. In the Solution Explorer, right-click your application and select `Add', `New Item...'. From `Visual Studio installed templates' select `ADO.NET Entity Data Model'. Click `Add'. FIGURE GOES HERE: Add Entity Data Model 2. You will now see the Entity Data Model Wizard. You will use the wizard to generate the Entity Data Model from the world example database. Select the icon ` Generate from database'. Click `Next'. FIGURE GOES HERE: Entity Data Model Wizard Screen 1 3. You can now select the connection you made earlier to the World database. If you have not already done so, you can create the new connection at this time by clicking `New Connection...'. For further instructions on creating a connection to a database see *Note connector-net-visual-studio-making-a-connection::. FIGURE GOES HERE: Entity Data Model Wizard Screen 2 4. Make a note of the entity connection settings to be used in App.Config, as these will be used later to write the necessary control code. 5. Click `Next'. 6. The Entity Data Model Wizard connects to the database. You are then presented with a tree structure of the database. From this you can select the object you would like to include in your model. If you had created Views and Stored Routines these will be displayed along with any tables. In this example you just need to select the tables. Click `Finish' to create the model and exit the wizard. FIGURE GOES HERE: Entity Data Model Wizard Screen 3 7. Visual Studio will generate the model and then display it. FIGURE GOES HERE: Entity Data Model Diagram 8. From the Visual Studio main menu select `Build', `Build Solution', to ensure that everything compiles correctly so far. *Adding a new Data Source* You will now add a new Data Source to your project and see how it can be used to read and write to the database. 1. From the Visual Studio main menu select `Data', `Add New Data Source...'. You will be presented with the Data Source Configuration Wizard. FIGURE GOES HERE: Entity Data Source Configuration Wizard Screen 1 2. Select the `Object' icon. Click `Next'. 3. You will now select the Object you wish to bind to. Expand the tree. In this tutorial you will select the city table. Once the city table has been selected click `Next'. FIGURE GOES HERE: Entity Data Source Configuration Wizard Screen 2 4. The wizard will confirm that the city object is to be added. Click `Finish'. FIGURE GOES HERE: Entity Data Source Configuration Wizard Screen 3 5. The city object will be display in the Data Sources panel. If the Data Sources panel is not displayed, select `Data', `Show Data Sources' from the Visual Studio main menu. The docked panel will then be displayed. FIGURE GOES HERE: Data Sources *Using the Data Source in a Windows Form* You will now learn how to use the Data Source in a Windows Form. 1. In the Data Sources panel select the Data Source you just created and drag and drop it onto the Form Designer. By default the Data Source object will be added as a Data Grid View control. Note that the Data Grid View control is bound to the `cityBindingSource' and the Navigator control is bound to `cityBindingNavigator'. FIGURE GOES HERE: Data Form Designer 2. Save and rebuild the solution before continuing. *Adding Code to Populate the Data Grid View* You are now ready to add code to ensure that the Data Grid View control will be populated with data from the City database table. 1. Double-click the form to access its code. 2. Add code to instatiate the Entity Data Model's EntityContainer object and retrieve data from the database to populate the control. FIGURE GOES HERE: Adding Code to the Form 3. Save and rebuild the solution. 4. Run the solution. Ensure the grid is populated and you can navigate the database. FIGURE GOES HERE: The Populated Grid Control *Adding Code to Save Changes to the Database* You will now add code to enable you to save changes to the database. The Binding source component ensures that changes made in the Data Grid View control are also made to the Entity classes bound to it. However, that data needs to be saved back from the entities to the database itself. This can be achieved by the enabling of the Save button in the Navigator control, and the addition of some code. 1. In the Form Designer, click the Save icon in the Form toolbar and ensure that its Enabled property is set to True. FIGURE GOES HERE: Save Button Enabled 2. Double-click the Save icon in the Form toolbar to display its code. 3. You now need to add code to ensure that data is saved to the database when the save button is clicked in the application. FIGURE GOES HERE: Adding Save Code to the Form 4. Once the code has been added, save the solution and rebuild it. Run the application and verify that changes made in the grid are saved.  File: manual.info, Node: connector-net-tutorials-entity-framework-databinding-linq-entities, Next: connector-net-tutorials-ssl, Prev: connector-net-tutorials-entity-framework-winform-data-source, Up: connector-net-tutorials 21.2.4.11 Tutorial: Databinding in ASP.NET using LINQ on Entities ................................................................. In this tutorial you create an ASP.NET web page that binds LINQ queries to entities using the Entity Framework mapping. If you have not already done so, you should install the World example database prior to attempting this tutorial. Instructions on where to obtain the database and instructions on how to install it where given in the tutorial *Note connector-net-tutorials-entity-framework-winform-data-source::. *Creating an ASP.NET web site* In this part of the tutorial you will create an ASP.NET web site. The web site will use the World database. The main web page will feature a drop down list from which you can select a country, data about that country's cities will then be displayed in a grid view control. 1. From the Visual Studio main menu select `File', `New', `Web Site...'. 2. From the Visual Studio installed templates select `ASP.NET Web Site'. Click `OK'. You will be presented with the Source view of your web page by default. 3. Click the Design view tab situated underneath the Source view panel. FIGURE GOES HERE: The Design Tab 4. In the Design view panel, enter some text to decorate the blank web page. 5. Click Toolbox. From the list of controls select `DropDownList'. Drag and drop the control to a location beneath the text on your web page. FIGURE GOES HERE: Drop Down List 6. From the `DropDownList' control's context menu, ensure that the `Enable AutoPostBack' check box is enabled. This will ensure the control's event handler is called when an item is selected. The user's choice will in turn be used to populate the `GridView' control. FIGURE GOES HERE: Enable AutoPostBack 7. From the Toolbox select the `GridView' control. FIGURE GOES HERE: Grid View Control Drag and drop the Grid Vew control to a location just below the Drop Down List you already placed. FIGURE GOES HERE: Placed Grid Vew Control 8. At this point it is recommended that you save your solution, and build the solution to ensure that there are no errors. 9. If you run the solution you will see that the text and drop down list are displayed, but the list is empty. Also, the grid view does not appear at all. Adding this functionality is described in the following sections. At this stage you have a web site that will build, but further functionality is required. The next step will be to use the Entity Framework to create a mapping from the World database into entities that you can control programmatically. *Creating an ADO.NET Entity Data Model* In this stage of the tutorial you will add an ADO.NET Entity Data Model to your project, using the World database at the storage level. The procedure for doing this is described in the tutorial *Note connector-net-tutorials-entity-framework-winform-data-source::, and so will not be repeated here. *Populating a Drop Data List Box with using the results of a entity LINQ query* In this part of the tutorial you will write code to populate the DropDownList control. When the web page loads the data to populate the list will be achieved by using the results of a LINQ query on the model created previously. 1. In the Design view panel, double-click any blank area. This brings up the Page_Load method. 2. Modify the relevant section of code according to the following listing: ... public partial class _Default : System.Web.UI.Page { worldModel.worldEntities we; protected void Page_Load(object sender, EventArgs e) { we = new worldModel.worldEntities(); if (!IsPostBack) { var countryQuery = from c in we.country orderby c.Name select new { c.Code, c.Name }; DropDownList1.DataValueField = "Code"; DropDownList1.DataTextField = "Name"; DropDownList1.DataSource = countryQuery; DataBind(); } } ... Note that the list control only needs to be populated when the page first loads. The conditional code ensures that if the page is subsequently reloaded, the list control is not repopulated, which would cause the user selection to be lost. 3. Save the solution, build it and run it. You should see the list control has been populated. You can select an item, but as yet the grid view control does not appear. At this point you have a working Drop Down List control, populated by a LINQ query on your entity data model. *Populating a Grid View control using an entity LINQ query* In the last part of this tutorial you will populate the Grid View Control using a LINQ query on your entity data model. 1. In the Design view, double-click the `DropDownList' control. This causes its SelectedIndexChanged code to be displayed. This method is called when a user selects an item in the list control and thus fires an AutoPostBack event. 2. Modify the relevant section of code accordingly to the following listing: ... protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e) { var cityQuery = from c in we.city where c.CountryCode == DropDownList1.SelectedValue orderby c.Name select new { c.Name, c.Population, c.CountryCode }; GridView1.DataSource = cityQuery; DataBind(); } ... The grid view control is populated from the result of the LINQ query on the entity data model. 3. As a check compare your code to that shown in the following screenshot: FIGURE GOES HERE: Source Code 4. Save, build and run the solution. As you select a country you will see its cities are displayed in the grid view control. FIGURE GOES HERE: The Working Web Site In this tutorial you have seen how to create an ASP.NET web site, you have also seen how you can access a MySQL database using LINQ queries on an entity data model.  File: manual.info, Node: connector-net-tutorials-ssl, Next: connector-net-tutorials-mysqlscript, Prev: connector-net-tutorials-entity-framework-databinding-linq-entities, Up: connector-net-tutorials 21.2.4.12 Tutorial: Using SSL with MySQL Connector/NET ...................................................... In this tutorial you will learn how you can use MySQL Connector/NET to connect to a MySQL server configured to use SSL. Support for SSL client certificates was added with MySQL Connector/NET 6.2. MySQL Server uses the PEM format for certificates and private keys. This tutorial will use the test certificates from the server test suite by way of example. You can obtain the MySQL Server source code from MySQL Downloads (http://dev.mysql.com/downloads/mysql/5.1.html#source). The certificates can be found in the directory `./mysql-test/std_data'. To carry out the steps in this tutorial you will also need to have Open SSL installed. This can be downloaded for Microsoft Windows at no charge from Shining Light Productions (http://www.slproweb.com/products/Win32OpenSSL.html). Further details on the connection string options used in this tutorial can be found at *Note connector-net-connection-options::. *Configuring the MySQL Server to use SSL* 1. In the MySQL Server configuration file, set the SSL parameters as follows: ssl-ca=path/to/repo/mysql-test/std_data/cacert.pem ssl-cert=path/to/repo/mysql-test/std_data/server-cert.pem ssl-key=path/to/repo/mysql-test/std_data/server-key.pem Adjust the directories according to the location in which you installed the MySQL source code. 2. In this step you create a test user and set the user to require SSL. Using the MySQL Command Line Client, connect as root and create the user `sslclient'. 3. To set privileges and requirements, issue the following command: GRANT ALL PRIVILEGES ON *.* TO sslclient@'%' REQUIRE SSL; * Creating a certificate file to use with the .NET client* 1. The .NET client does not use the PEM file format, as .NET does not support this format natively. You will be using test client certificates from the same server repository, for the purposes of this example. You will need to convert these to PFX format first. This format is also known as PKCS#12. An article describing this procedure can be found at the Citrix website (http://support.citrix.com/article/CTX106630). From the directory `SERVER-REPOSITORY-ROOT/mysql-test/std_data', issue the following command: openssl pkcs12 -export -in client-cert.pem -inkey client-key.pem -certfile cacert.pem -out client.pfx 2. When asked for an export password, enter the password `pass'. The file `client.pfx' will be generated. This file is used in the remainder of the tutorial. *Connecting to the server using a file-based certificate* 1. You will use PFX file, `client.pfx' you created in the previous step to authenticate the client. The following example demonstrates how to connect using the `SSL Mode', `CertificateFile' and `CertificatePassword' connection string options: using (MySqlConnection connection = new MySqlConnection( "database=test;user=sslclient;" + "CertificateFile=H:\\bzr\\mysql-trunk\\mysqlest\\std_data\\client.pfx" + "CertificatePassword=pass;" + "SSL Mode=Required ")) { connection.Open(); } The path to the certificate file will need to be changed to reflect your individual installation. *Connecting to the server using a store-based certificate* 1. The first step is to import the PFX file, `client.pfx', into the Personal Store. Double-click the file in Windows explorer. This launches the Certificate Import Wizard. 2. Follow the steps dictated by the wizard, and when prompted for the password for the PFX file, enter `pass'. 3. Click `Finish' to close the wizard and import the certificate into the personal store. *Examine certificates in the Personal Store* 1. Start the Microsoft Management Console by entering `mmc.exe' at a command prompt. 2. Select `File', `Add/Remove snap-in'. Click `Add'. Select `Certificates' from the list of available snap-ins in the dialog. 3. Click `Add' button in the dialog, and select the `My user account' radio button. This is used for personal certificates. 4. Click the `Finish' button. 5. Click `OK' to close the Add/Remove Snap-in dialog. 6. You will now have `Certificates - Current User' displayed in the left panel of the Microsoft Management Console. Expand the Certificates - Current User tree item and select `Personal', `Certificates'. The right-hand panel will display a certificate issued to MySQL. This is the certificate that was previously imported. Double-click the certificate to display its details. 7. After you have imported the certificate to the Personal Store, you can use a more succint connection string to connect to the database, as illustrated by the following code: using (MySqlConnection connection = new MySqlConnection( "database=test;user=sslclient;" + "Certificate Store Location=CurrentUser;" + "SSL Mode=Required")) { connection.Open(); } *Certificate Thumbprint Parameter* If you have a large number of certificates in your store, and many have the same Issuer, this can be a source of confusion and result in the wrong certificate being used. To alleviate this situation, there is an optional Certificate Thumbprint parameter that can additionally be specified as part of the connection string. As mentioned before, you can double-click a certificate in the Microsoft Management Console to display the certificate's details. When the Certificate dialog is displayed click the `Details' tab and scroll down to see the thumbprint. The thumbprint will typically be a number such as `‎47 94 36 00 9a 40 f3 01 7a 14 5c f8 47 9e 76 94 d7 aa de f0'. This thumbprint can be used in the connection string, as the following code illustrates: using (MySqlConnection connection = new MySqlConnection( "database=test;user=sslclient;" + "Certificate Store Location=CurrentUser;" + "Certificate Thumbprint=479436009a40f3017a145cf8479e7694d7aadef0;"+ "SSL Mode=Required")) { connection.Open(); } Spaces in the thumbprint parameter are optional and the value is case-insensitive.  File: manual.info, Node: connector-net-tutorials-mysqlscript, Next: connector-net-tutorials-efmodel-ddl, Prev: connector-net-tutorials-ssl, Up: connector-net-tutorials 21.2.4.13 Tutorial: Using MySqlScript ..................................... * Menu: * connector-net-tutorials-mysqlscript-delimiter:: Using Delimiters with MySqlScript In this tutorial you will learn how to use the MySqlScript class. This class enables you to execute a series of statements. Depending on the circumstances, this can be more convenient than using the MySqlCommand approach. Further details of the MySqlScript class can be found in the reference documentation supplied with MySQL Connector/NET. If you wish to run the example programs in this tutorial, you will need to set up a simple test database and table. This can be achieved using the MySQL Command Line Client or MySql Workbench. Commands for the MySQL Command Line Client are given here: 1. `CREATE DATABASE TestDB;' 2. `USE TestDB;' 3. `CREATE TABLE TestTable (id INT NOT NULL PRIMARY KEY AUTO_INCREMENT, name VARCHAR(100));' The main method of the MySqlScript class is the Execute method. This method causes the script (sequence of statements) assigned to the Query property of the MySqlScript object to be executed. Note the Query property can be set through the MySqlScript constructor or using the Query property. Execute returns the number of statements executed. The MySqlScript object will execute the specified script on the connection set using the Connection property. Again, this property can be set directly or through the MySqlScript constructor. The following code snipets illustrate this: string sql = "SELECT * FROM TestTable"; ... MySqlScript script = new MySqlScript(conn, sql); ... MySqlScript script = new MySqlScript(); script.Query = sql; script.Connection = conn; ... script.Execute(); The MySqlScript class has several events associated with it. There are: 1. Error - generated in an error occurs. 2. ScriptCompleted - generated when the script successfully completes execution. 3. StatementExecuted - generated after each statement is executed. It is possible to assign event handlers to each of these events. These user-provided routines will be called back should the connected event occur. The following code shows how the event handlers are set up. script.Error += new MySqlScriptErrorEventHandler(script_Error); script.ScriptCompleted += new EventHandler(script_ScriptCompleted); script.StatementExecuted += new MySqlStatementExecutedEventHandler(script_StatementExecuted); In VisualStudio you can use tab completion to fill out stub routines for you, to save typing. To do this start by typing, for example, `script.Error +='. Then press `TAB', and then press `TAB' again. The assignment will be completed, and a stub event handler created. A complete working example is shown below: using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Data; using MySql.Data; using MySql.Data.MySqlClient; namespace MySqlScriptTest { class Program { static void Main(string[] args) { string connStr = "server=localhost;user=root;database=TestDB;port=3306;password=******;"; MySqlConnection conn = new MySqlConnection(connStr); try { Console.WriteLine("Connecting to MySQL..."); conn.Open(); string sql = "INSERT INTO TestTable(name) VALUES ('Superman');" + "INSERT INTO TestTable(name) VALUES ('Batman');" + "INSERT INTO TestTable(name) VALUES ('Wolverine');" + "INSERT INTO TestTable(name) VALUES ('Storm');"; MySqlScript script = new MySqlScript(conn, sql); script.Error += new MySqlScriptErrorEventHandler(script_Error); script.ScriptCompleted += new EventHandler(script_ScriptCompleted); script.StatementExecuted += new MySqlStatementExecutedEventHandler(script_StatementExecuted); int count = script.Execute(); Console.WriteLine("Executed " + count + " statement(s)."); Console.WriteLine("Delimiter: " + script.Delimiter); } catch (Exception ex) { Console.WriteLine(ex.ToString()); } conn.Close(); Console.WriteLine("Done."); } static void script_StatementExecuted(object sender, MySqlScriptEventArgs args) { Console.WriteLine("script_StatementExecuted"); } static void script_ScriptCompleted(object sender, EventArgs e) { /// EventArgs e will be EventArgs.Empty for this method Console.WriteLine("script_ScriptCompleted!"); } static void script_Error(Object sender, MySqlScriptErrorEventArgs args) { Console.WriteLine("script_Error: " + args.Exception.ToString()); } } } Note that in the script_ScriptCompleted event handler, the EventArgs parameter `e' will be `EventArgs.Empty'. In the case of the `ScriptCompleted' event there is no additional data to be obtained, which is why the event object is `EventArgs.Empty'.  File: manual.info, Node: connector-net-tutorials-mysqlscript-delimiter, Prev: connector-net-tutorials-mysqlscript, Up: connector-net-tutorials-mysqlscript 21.2.4.14 Using Delimiters with MySqlScript ........................................... Depending on the nature of the script, you made need control of the delimiter used to separate the statements that will make up a script. The most common example of this is where you have a multi-statement stored routine as part of your script. In this case if the default delimiter of `;' is used you will get an error when you attempt to execute the script. For example, consider the following stored routine: CREATE PROCEDURE test_routine() BEGIN SELECT name FROM TestTable ORDER BY name; SELECT COUNT(name) FROM TestTable; END This routine actually needs to be executed on the MySQL Server as a single statement. However, with the default delimiter of `;', the MySqlScript class would interpret the above as two statements, the first being: CREATE PROCEDURE test_routine() BEGIN SELECT name FROM TestTable ORDER BY name; Executing this as a statement would generate an error. To solve this problem MySqlScript supports the ability to set a different delimiter. This is achieved through the Delimiter property. For example, you could set the delimiter to `??', in which case the above stored routine would no longer generate an error when executed. Multiple statements can be delimited in the script, so for example, you could have a three statement script such as: string sql = "DROP PROCEDURE IF EXISTS test_routine??" + "CREATE PROCEDURE test_routine() " + "BEGIN " + "SELECT name FROM TestTable ORDER BY name;" + "SELECT COUNT(name) FROM TestTable;" + "END??" + "CALL test_routine()"; You can change the delimiter back at any point by setting the Delimiter property. The following code shows a complete working example: using System; using System.Collections.Generic; using System.Linq; using System.Text; using MySql.Data; using MySql.Data.MySqlClient; namespace ConsoleApplication8 { class Program { static void Main(string[] args) { string connStr = "server=localhost;user=root;database=TestDB;port=3306;password=******;"; MySqlConnection conn = new MySqlConnection(connStr); try { Console.WriteLine("Connecting to MySQL..."); conn.Open(); string sql = "DROP PROCEDURE IF EXISTS test_routine??" + "CREATE PROCEDURE test_routine() " + "BEGIN " + "SELECT name FROM TestTable ORDER BY name;" + "SELECT COUNT(name) FROM TestTable;" + "END??" + "CALL test_routine()"; MySqlScript script = new MySqlScript(conn); script.Query = sql; script.Delimiter = "??"; int count = script.Execute(); Console.WriteLine("Executed " + count + " statement(s)"); script.Delimiter = ";"; Console.WriteLine("Delimiter: " + script.Delimiter); Console.WriteLine("Query: " + script.Query); } catch (Exception ex) { Console.WriteLine(ex.ToString()); } conn.Close(); Console.WriteLine("Done."); } } }  File: manual.info, Node: connector-net-tutorials-efmodel-ddl, Prev: connector-net-tutorials-mysqlscript, Up: connector-net-tutorials 21.2.4.15 Tutorial: Generating MySQL DDL from an Entity Framework Model ....................................................................... In this tutorial you will learn how to create MySQL DDL from an Entity Framework model. You will need to use Visual Studio 2010 and MySQL Connector/NET 6.3 to carry out this tutorial. 1. Create a new console application in Visual Studio 2010. 2. Using the `Solution Explorer' add a reference to `MySql.Data.Entity'. 3. From the `Solution Explorer' select `Add', `New Item'. In the `Add New Item' dialog select `Online Templates'. Select `ADO.NET Entity Data Model' and click `Add'. The `Entity Data Model' dialog will be displayed. 4. In the `Entity Data Model' dialog select `Empty Model'. Click `Finish'. A blank model will be created. 5. Create a simple model. A single Entity will do for the purposes of this tutorial. 6. In the `Properties' panel select `ConceptualEntityModel' from the drop-down listbox. 7. In the `Properties' panel, locate the `DDL Generation Template' in the category `Database Script Generation'. 8. For the `DDL Generation' property select `SSDLToMySQL.tt(VS)' from the drop-down listbox. 9. Save the solution. 10. Right-click an empty space in the model design area. The context-sensitive menu will be displayed. 11. From the context-sensitive menu select `Generate Database from Model'. The `Generate Database Wizard' dialog will be displayed. 12. In the `Generate Database Wizard' dialog select an existing connection, or create a new connection to a server. Select an appropriate radio button to show or hide sensitive data. For the purposes of this tutorial you can select `Yes' (although you may not want to do this for commercial applications). 13. Click `Next'. MySQL compatible DDL code will be generated. Click `Finish' to exit the wizard. You have seen how to create MySQL DDL code from an Entity Framework model.  File: manual.info, Node: connector-net-programming, Next: connector-net-connection-options, Prev: connector-net-tutorials, Up: connector-net 21.2.5 Connector/NET Programming -------------------------------- * Menu: * connector-net-programming-connecting:: Connecting to MySQL Using Connector/NET * connector-net-programming-connecting-connection-string:: Creating a Connection String * connector-net-programming-mysqlcommand:: Using MySqlCommand * connector-net-programming-connection-pooling:: Using Connector/NET with Connection Pooling * connector-net-programming-prepared:: Using the Connector/NET with Prepared Statements * connector-net-programming-stored:: Accessing Stored Procedures with Connector/NET * connector-net-programming-blob:: Handling BLOB Data With Connector/NET * connector-net-programming-crystal:: Using Connector/NET with Crystal Reports * connector-net-programming-datetime:: Handling Date and Time Information in Connector/NET * connector-net-programming-asp-provider:: ASP.NET Provider Model * connector-net-programming-binary-issues:: Binary/Nonbinary Issues * connector-using-character-sets:: Character Sets * content-advanced-topics-medium-trust:: Working with medium trust * connector-net-programming-tracing:: Using the MySQL Connector/NET Trace Source Object * connector-net-programming-bulk-loader:: Using the Bulk Loader Connector/NET comprises several classes that are used to connect to the database, execute queries and statements, and manage query results. The following are the major classes of Connector/NET: * `MySqlCommand': Represents an SQL statement to execute against a MySQL database. * `MySqlCommandBuilder': Automatically generates single-table commands used to reconcile changes made to a DataSet with the associated MySQL database. * `MySqlConnection': Represents an open connection to a MySQL Server database. * `MySqlDataAdapter': Represents a set of data commands and a database connection that are used to fill a data set and update a MySQL database. * `MySqlDataReader': Provides a means of reading a forward-only stream of rows from a MySQL database. * `MySqlException': The exception that is thrown when MySQL returns an error. * `MySqlHelper': Helper class that makes it easier to work with the provider. * `MySqlTransaction': Represents an SQL transaction to be made in a MySQL database. In the following sections you will learn about some common use cases for Connector/NET, including BLOB handling, date handling, and using Connector/NET with common tools such as Crystal Reports.  File: manual.info, Node: connector-net-programming-connecting, Next: connector-net-programming-connecting-connection-string, Prev: connector-net-programming, Up: connector-net-programming 21.2.5.1 Connecting to MySQL Using Connector/NET ................................................ *Introduction* All interaction between a .NET application and the MySQL server is routed through a `MySqlConnection' object. Before your application can interact with the server, a `MySqlConnection' object must be instanced, configured, and opened. Even when using the `MySqlHelper' class, a `MySqlConnection' object is created by the helper class. In this section, we will describe how to connect to MySQL using the `MySqlConnection' object.  File: manual.info, Node: connector-net-programming-connecting-connection-string, Next: connector-net-programming-mysqlcommand, Prev: connector-net-programming-connecting, Up: connector-net-programming 21.2.5.2 Creating a Connection String ..................................... * Menu: * connector-net-programming-connecting-open:: Opening a Connection * connector-net-programming-connecting-errors:: Handling Connection Errors * connector-net-programming-getschema:: Using GetSchema on a Connection The `MySqlConnection' object is configured using a connection string. A connection string contains sever key/value pairs, separated by semicolons. Each key/value pair is joined with an equal sign. The following is a sample connection string: Server=127.0.0.1;Uid=root;Pwd=12345;Database=test; In this example, the `MySqlConnection' object is configured to connect to a MySQL server at `127.0.0.1', with a user name of `root' and a password of `12345'. The default database for all statements will be the `test' database. The following options are available: *Note*: Using the '@' symbol for parameters is now the preferred approach although the old pattern of using '?' is still supported. Please be aware however that using '@' can cause conflicts when user variables are also used. To help with this situation please see the documentation on the `Allow User Variables' connection string option, which can be found here: *Note connector-net-programming-connecting-connection-string::. The `Old Syntax' connection string option has now been deprecated.  File: manual.info, Node: connector-net-programming-connecting-open, Next: connector-net-programming-connecting-errors, Prev: connector-net-programming-connecting-connection-string, Up: connector-net-programming-connecting-connection-string 21.2.5.3 Opening a Connection ............................. Once you have created a connection string it can be used to open a connection to the MySQL server. The following code is used to create a `MySqlConnection' object, assign the connection string, and open the connection. Visual Basic Example Dim conn As New MySql.Data.MySqlClient.MySqlConnection Dim myConnectionString as String myConnectionString = "server=127.0.0.1;" _ & "uid=root;" _ & "pwd=12345;" _ & "database=test;" Try conn.ConnectionString = myConnectionString conn.Open() Catch ex As MySql.Data.MySqlClient.MySqlException MessageBox.Show(ex.Message) End Try C# Example MySql.Data.MySqlClient.MySqlConnection conn; string myConnectionString; myConnectionString = "server=127.0.0.1;uid=root;" + "pwd=12345;database=test;"; try { conn = new MySql.Data.MySqlClient.MySqlConnection(); conn.ConnectionString = myConnectionString; conn.Open(); } catch (MySql.Data.MySqlClient.MySqlException ex) { MessageBox.Show(ex.Message); } You can also pass the connection string to the constructor of the `MySqlConnection' class: Visual Basic Example Dim myConnectionString as String myConnectionString = "server=127.0.0.1;" _ & "uid=root;" _ & "pwd=12345;" _ & "database=test;" Try Dim conn As New MySql.Data.MySqlClient.MySqlConnection(myConnectionString) conn.Open() Catch ex As MySql.Data.MySqlClient.MySqlException MessageBox.Show(ex.Message) End Try C# Example MySql.Data.MySqlClient.MySqlConnection conn; string myConnectionString; myConnectionString = "server=127.0.0.1;uid=root;" + "pwd=12345;database=test;"; try { conn = new MySql.Data.MySqlClient.MySqlConnection(myConnectionString); conn.Open(); } catch (MySql.Data.MySqlClient.MySqlException ex) { MessageBox.Show(ex.Message); } Once the connection is open it can be used by the other Connector/NET classes to communicate with the MySQL server.  File: manual.info, Node: connector-net-programming-connecting-errors, Next: connector-net-programming-getschema, Prev: connector-net-programming-connecting-open, Up: connector-net-programming-connecting-connection-string 21.2.5.4 Handling Connection Errors ................................... Because connecting to an external server is unpredictable, it is important to add error handling to your .NET application. When there is an error connecting, the `MySqlConnection' class will return a `MySqlException' object. This object has two properties that are of interest when handling errors: * `Message': A message that describes the current exception. * `Number': The MySQL error number. When handling errors, you can your application's response based on the error number. The two most common error numbers when connecting are as follows: * `0': Cannot connect to server. * `1045': Invalid user name and/or password. The following code shows how to adapt the application's response based on the actual error: Visual Basic Example Dim myConnectionString as String myConnectionString = "server=127.0.0.1;" _ & "uid=root;" _ & "pwd=12345;" _ & "database=test;" Try Dim conn As New MySql.Data.MySqlClient.MySqlConnection(myConnectionString) conn.Open() Catch ex As MySql.Data.MySqlClient.MySqlException Select Case ex.Number Case 0 MessageBox.Show("Cannot connect to server. Contact administrator") Case 1045 MessageBox.Show("Invalid username/password, please try again") End Select End Try C# Example MySql.Data.MySqlClient.MySqlConnection conn; string myConnectionString; myConnectionString = "server=127.0.0.1;uid=root;" + "pwd=12345;database=test;"; try { conn = new MySql.Data.MySqlClient.MySqlConnection(myConnectionString); conn.Open(); } catch (MySql.Data.MySqlClient.MySqlException ex) { switch (ex.Number) { case 0: MessageBox.Show("Cannot connect to server. Contact administrator"); case 1045: MessageBox.Show("Invalid username/password, please try again"); } } *Important*: Note that if you are using multilanguage databases you must specify the character set in the connection string. If you do not specify the character set, the connection defaults to the `latin1' charset. You can specify the character set as part of the connection string, for example: MySqlConnection myConnection = new MySqlConnection("server=127.0.0.1;uid=root;" + "pwd=12345;database=test;Charset=latin1;");  File: manual.info, Node: connector-net-programming-getschema, Prev: connector-net-programming-connecting-errors, Up: connector-net-programming-connecting-connection-string 21.2.5.5 Using GetSchema on a Connection ........................................ * Menu: * connector-net-programming-getschema-collections:: Collections The `GetSchema()' method of the connection object can be used to retrieve schema information about the database currently connected to. The schema information is returned in the form of a `DataTable'. The schema information is organized into a number of collections. Different forms of the `GetSchema()' method can be used depending on the information required. There are three forms of the `GetSchema()' method: * `GetSchema()' - This call will return a list of available collections. * `GetSchema(String)' - This call returns information about the collection named in the string parameter. If the string `MetaDataCollections' is used then a list of all available collections is returned. This is the same as calling `GetSchema()' without any parameters. * `GetSchema(String, String[])' - In this call the first string parameter represents the collection name, and the second parameter represents a string array of restriction values. Restriction values limit the amount of data that will be returned. Restriction values are explained in more detail in the Microsoft .NET documentation (http://msdn.microsoft.com/en-us/library/ms254934(VS.80).aspx).  File: manual.info, Node: connector-net-programming-getschema-collections, Prev: connector-net-programming-getschema, Up: connector-net-programming-getschema 21.2.5.6 Collections .................... The collections can be broadly grouped into two types: collections that are common to all data providers, and collections specific to a particular provider. *Common* The following collections are common to all data providers: * MetaDataCollections * DataSourceInformation * DataTypes * Restrictions * ReservedWords *Provider-specific* The following are the collections currently provided by MySQL Connector/NET, in addition to the common collections above: * Databases * Tables * Columns * Users * Foreign Keys * IndexColumns * Indexes * Foreign Key Columns * UDF * Views * ViewColumns * Procedure Parameters * Procedures * Triggers *Example Code* A list of available collections can be obtained using the following code: using System; using System.Data; using System.Text; using MySql.Data; using MySql.Data.MySqlClient; namespace ConsoleApplication2 { class Program { private static void DisplayData(System.Data.DataTable table) { foreach (System.Data.DataRow row in table.Rows) { foreach (System.Data.DataColumn col in table.Columns) { Console.WriteLine("{0} = {1}", col.ColumnName, row[col]); } Console.WriteLine("============================"); } } static void Main(string[] args) { string connStr = "server=localhost;user=root;database=world;port=3306;password=******;"; MySqlConnection conn = new MySqlConnection(connStr); try { Console.WriteLine("Connecting to MySQL..."); conn.Open(); DataTable table = conn.GetSchema("MetaDataCollections"); //DataTable table = conn.GetSchema("UDF"); DisplayData(table); conn.Close(); } catch (Exception ex) { Console.WriteLine(ex.ToString()); } Console.WriteLine("Done."); } } } Further information on the `GetSchema()' method and schema collections can be found in the Microsoft .NET documentation (http://msdn.microsoft.com/en-us/library/kcax58fh(VS.80).aspx).  File: manual.info, Node: connector-net-programming-mysqlcommand, Next: connector-net-programming-connection-pooling, Prev: connector-net-programming-connecting-connection-string, Up: connector-net-programming 21.2.5.7 Using MySqlCommand ........................... A MySqlCommand has the `CommandText' and `CommandType' properties associated with it. The `CommandText' will be handled differently depending on the setting of `CommandType'. `CommandType' can be one of: 1. Text - A SQL text command (default) 2. StoredProcedure - The name of a Stored Procedure 3. TableDirect - The name of a table (new in Connector/NET 6.2) The default `CommandType', `Text', is used for executing queries and other SQL commands. Some example of this can be found in the following section *Note connector-net-tutorials-sql-command::. If `CommandType' is set to `StoredProcedure', `CommandText' should be set to the name of the Stored Procedure to access. If `CommandType' is set to `TableDirect', all rows and columns of the named table will be returned when you call one of the Execute methods. In effect, this command performs a `SELECT *' on the table specified. The `CommandText' property is set to the name of the table you wish to query. This is illustrated by the following code snippet: ... MySqlCommand cmd = new MySqlCommand(); cmd.CommandText = "mytable"; cmd.Connection = someConnection; cmd.CommandType = CommandType.TableDirect; MySqlDataReader reader = cmd.ExecuteReader(); while (reader.Read()) { Console.WriteLn(reader[0], reader[1]...); } ... Examples of using the CommandType of StoredProcedure can be found in the section *Note connector-net-programming-stored::. Commands can have a timeout associated with them. This is useful as you may not want a situation were a command takes up an excessive amount of time. A timeout can be set using the `CommandTimeout' property. The following code snippet sets a timeout of one minute: MySqlCommand cmd = new MySqlCommand(); cmd.CommandTimeout = 60; The default value is 30 secs. A value of 0 indicates an indefinite wait and should be avoided. Note the default command timeout can be changed using the connection string option `Default Command Timeout'. Prior to MySQL Connector/NET 6.2, `MySqlCommand.CommandTimeout' included user processing time, that is processing time not related to direct use of the connector. Timeout was implemented through a .NET Timer, that triggered after `CommandTimeout' seconds. This timer consumed a thread. MySQL Connector/NET 6.2 introduced timeouts that are aligned with how Microsoft handles `SqlCommand.CommandTimeout'. This property is the cumulative timeout for all network reads and writes during command execution or processing of the results. A timeout can still occur in the `MySqlReader.Read' method after the first row is returned, and does not include user processing time, only IO operations. The 6.2 implementation uses the underlying stream timeout facility, so is more efficient in that it does not require the additional timer thread as was the case with the previous implementation. Further details on this can be found in the relevant Microsoft documentation (http://msdn.microsoft.com/en-us/library/system.data.sqlclient.sqlcommand.commandtimeout.aspx).  File: manual.info, Node: connector-net-programming-connection-pooling, Next: connector-net-programming-prepared, Prev: connector-net-programming-mysqlcommand, Up: connector-net-programming 21.2.5.8 Using Connector/NET with Connection Pooling .................................................... The Connector/NET supports connection pooling. This is enabled by default, but can be turned off using connection string options. See *Note connector-net-programming-connecting-connection-string:: for further information. Connection pooling works by keeping the native connection to the server live when the client disposes of a `MySqlConnection'. Subsequently, if a new `MySqlConnection' object is opened, it will be created from the connection pool, rather than creating a new native connection. This improves performance. To work as designed, it is best to let the connection pooling system manage all connections. You should not create a globally accessible instance of `MySqlConnection' and then manually open and close it. This interferes with the way the pooling works and can lead to unpredictable results or even exceptions. One approach that simplifies things is to avoid manually creating a `MySqlConnection' object. Instead use the overloaded methods that take a connection string as an argument. Using this approach, Connector/NET will automatically create, open, close and destroy connections, using the connection pooling system for best performance. Typed Datasets and the `MembershipProvider' and `RoleProvider' classes use this approach. Most classes that have methods that take a `MySqlConnection' as an argument, also have methods that take a connection string as an argument. This includes `MySqlDataAdapter'. Instead of manually creating `MySqlCommand' objects, you can use the static methods of the `MySqlHelper' class. These take a connection string as an argument, and they fully support connection pooling. Starting with MySQL Connector/NET 6.2, there is a background job that runs every three minutes and removes connections from pool that have been idle (unused) for more than three minutes. The pool cleanup frees resources on both client and server side. This is because on the client side every connection uses a socket, and on the server side every connection uses a socket and a thread. Prior to this change, connections were never removed from the pool, and the pool always contained the peak number of open connections. For example, a web application that peaked at 1000 concurrent database connections would consume 1000 threads and 1000 open sockets at the server, without ever freeing up those resources from the connection pool. Note, connections, no matter how old, will not be closed if the number of connections in the pool is less than or equal to the value set by the `Min Pool Size' connection string parameter.  File: manual.info, Node: connector-net-programming-prepared, Next: connector-net-programming-stored, Prev: connector-net-programming-connection-pooling, Up: connector-net-programming 21.2.5.9 Using the Connector/NET with Prepared Statements ......................................................... * Menu: * connector-net-programming-prepared-preparing:: Preparing Statements in Connector/NET *Introduction* As of MySQL 4.1, it is possible to use prepared statements with Connector/NET. Use of prepared statements can provide significant performance improvements on queries that are executed more than once. Prepared execution is faster than direct execution for statements executed more than once, primarily because the query is parsed only once. In the case of direct execution, the query is parsed every time it is executed. Prepared execution also can provide a reduction of network traffic because for each execution of the prepared statement, it is necessary only to send the data for the parameters. Another advantage of prepared statements is that it uses a binary protocol that makes data transfer between client and server more efficient.  File: manual.info, Node: connector-net-programming-prepared-preparing, Prev: connector-net-programming-prepared, Up: connector-net-programming-prepared 21.2.5.10 Preparing Statements in Connector/NET ............................................... To prepare a statement, create a command object and set the `.CommandText' property to your query. After entering your statement, call the `.Prepare' method of the `MySqlCommand' object. After the statement is prepared, add parameters for each of the dynamic elements in the query. After you enter your query and enter parameters, execute the statement using the `.ExecuteNonQuery()', `.ExecuteScalar()', or `.ExecuteReader' methods. For subsequent executions, you need only modify the values of the parameters and call the execute method again, there is no need to set the `.CommandText' property or redefine the parameters. Visual Basic Example Dim conn As New MySqlConnection Dim cmd As New MySqlCommand conn.ConnectionString = strConnection Try conn.Open() cmd.Connection = conn cmd.CommandText = "INSERT INTO myTable VALUES(NULL, @number, @text)" cmd.Prepare() cmd.Parameters.AddWithValue("@number", 1) cmd.Parameters.AddWithValue("@text", "One") For i = 1 To 1000 cmd.Parameters("@number").Value = i cmd.Parameters("@text").Value = "A string value" cmd.ExecuteNonQuery() Next Catch ex As MySqlException MessageBox.Show("Error " & ex.Number & " has occurred: " & ex.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error) End Try C# Example MySql.Data.MySqlClient.MySqlConnection conn; MySql.Data.MySqlClient.MySqlCommand cmd; conn = new MySql.Data.MySqlClient.MySqlConnection(); cmd = new MySql.Data.MySqlClient.MySqlCommand(); conn.ConnectionString = strConnection; try { conn.Open(); cmd.Connection = conn; cmd.CommandText = "INSERT INTO myTable VALUES(NULL, @number, @text)"; cmd.Prepare(); cmd.Parameters.AddWithValue("@number", 1); cmd.Parameters.AddWithValue("@text", "One"); for (int i=1; i <= 1000; i++) { cmd.Parameters["@number"].Value = i; cmd.Parameters["@text"].Value = "A string value"; cmd.ExecuteNonQuery(); } } catch (MySql.Data.MySqlClient.MySqlException ex) { MessageBox.Show("Error " + ex.Number + " has occurred: " + ex.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error); }  File: manual.info, Node: connector-net-programming-stored, Next: connector-net-programming-blob, Prev: connector-net-programming-prepared, Up: connector-net-programming 21.2.5.11 Accessing Stored Procedures with Connector/NET ........................................................ * Menu: * connector-net-programming-stored-using:: Using Stored Routines from Connector/NET *Introduction* With the release of MySQL version 5 the MySQL server now supports stored procedures with the SQL 2003 stored procedure syntax. A stored procedure is a set of SQL statements that can be stored in the server. Once this has been done, clients do not need to keep reissuing the individual statements but can refer to the stored procedure instead. Stored procedures can be particularly useful in situations such as the following: * When multiple client applications are written in different languages or work on different platforms, but need to perform the same database operations. * When security is paramount. Banks, for example, use stored procedures for all common operations. This provides a consistent and secure environment, and procedures can ensure that each operation is properly logged. In such a setup, applications and users would not get any access to the database tables directly, but can only execute specific stored procedures. Connector/NET supports the calling of stored procedures through the `MySqlCommand' object. Data can be passed in and out of a MySQL stored procedure through use of the `MySqlCommand.Parameters' collection. *Note*: When you call a stored procedure, the command object makes an additional *Note `SELECT': select. call to determine the parameters of the stored procedure. You must ensure that the user calling the procedure has the `SELECT' privilege on the `mysql.proc' table to enable them to verify the parameters. Failure to do this will result in an error when calling the procedure. This section will not provide in-depth information on creating Stored Procedures. For such information, please refer to `http://dev.mysql.com/doc/mysql/en/stored-routines.html'. A sample application demonstrating how to use stored procedures with Connector/NET can be found in the `Samples' directory of your Connector/NET installation.  File: manual.info, Node: connector-net-programming-stored-using, Prev: connector-net-programming-stored, Up: connector-net-programming-stored 21.2.5.12 Using Stored Routines from Connector/NET .................................................. Stored procedures in MySQL can be created using a variety of tools. First, stored procedures can be created using the *Note `mysql': mysql. command-line client. Second, stored procedures can be created using MySQL Workbench. Finally, stored procedures can be created using the `.ExecuteNonQuery' method of the `MySqlCommand' object. It should be noted that, unlike the command-line and GUI clients, you are not required to specify a special delimiter when creating stored procedures in Connector/NET. To call a stored procedure using Connector/NET, you create a `MySqlCommand' object and pass the stored procedure name as the `.CommandText' property. You then set the `.CommandType' property to `CommandType.StoredProcedure'. After the stored procedure is named, you create one `MySqlCommand' parameter for every parameter in the stored procedure. `IN' parameters are defined with the parameter name and the object containing the value, `OUT' parameters are defined with the parameter name and the data type that is expected to be returned. All parameters need the parameter direction defined. After defining the parameters, you call the stored procedure by using the `MySqlCommand.ExecuteNonQuery()' method. Once the stored procedure is called, the values of the output parameters can be retrieved by using the `.Value' property of the `MySqlConnector.Parameters' collection. *Note*: When a stored procedure is called using `MySqlCommand.ExecuteReader', and the stored procedure has output parameters, the output parameters are only set after the `MySqlDataReader' returned by `ExecuteReader' is closed. The following C# example code demonstrates the use of stored procedures. It assumes the database 'employees' has already been created: using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Data; using MySql.Data; using MySql.Data.MySqlClient; namespace UsingStoredRoutines { class Program { static void Main(string[] args) { MySqlConnection conn = new MySqlConnection(); conn.ConnectionString = "server=localhost;user=root;database=employees;port=3306;password=******;"; MySqlCommand cmd = new MySqlCommand(); try { Console.WriteLine("Connecting to MySQL..."); conn.Open(); cmd.Connection = conn; cmd.CommandText = "DROP PROCEDURE IF EXISTS add_emp"; cmd.ExecuteNonQuery(); cmd.CommandText = "DROP TABLE IF EXISTS emp"; cmd.ExecuteNonQuery(); cmd.CommandText = "CREATE TABLE emp (empno INT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY, first_name VARCHAR(20), last_name VARCHAR(20), birthdate DATE)"; cmd.ExecuteNonQuery(); cmd.CommandText = "CREATE PROCEDURE add_emp(" + "IN fname VARCHAR(20), IN lname VARCHAR(20), IN bday DATETIME, OUT empno INT)" + "BEGIN INSERT INTO emp(first_name, last_name, birthdate) " + "VALUES(fname, lname, DATE(bday)); SET empno = LAST_INSERT_ID(); END"; cmd.ExecuteNonQuery(); } catch (MySqlException ex) { Console.WriteLine ("Error " + ex.Number + " has occurred: " + ex.Message); } conn.Close(); Console.WriteLine("Connection closed."); try { Console.WriteLine("Connecting to MySQL..."); conn.Open(); cmd.Connection = conn; cmd.CommandText = "add_emp"; cmd.CommandType = CommandType.StoredProcedure; cmd.Parameters.AddWithValue("@lname", "Jones"); cmd.Parameters["@lname"].Direction = ParameterDirection.Input; cmd.Parameters.AddWithValue("@fname", "Tom"); cmd.Parameters["@fname"].Direction = ParameterDirection.Input; cmd.Parameters.AddWithValue("@bday", "1940-06-07"); cmd.Parameters["@bday"].Direction = ParameterDirection.Input; cmd.Parameters.AddWithValue("@empno", MySqlDbType.Int32); cmd.Parameters["@empno"].Direction = ParameterDirection.Output; cmd.ExecuteNonQuery(); Console.WriteLine("Employee number: "+cmd.Parameters["@empno"].Value); Console.WriteLine("Birthday: " + cmd.Parameters["@bday"].Value); } catch (MySql.Data.MySqlClient.MySqlException ex) { Console.WriteLine("Error " + ex.Number + " has occurred: " + ex.Message); } conn.Close(); Console.WriteLine("Done."); } } } The following code shows the same application in Visual Basic: Imports System Imports System.Collections.Generic Imports System.Linq Imports System.Text Imports System.Data Imports MySql.Data Imports MySql.Data.MySqlClient Module Module1 Sub Main() Dim conn As New MySqlConnection() conn.ConnectionString = "server=localhost;user=root;database=world;port=3306;password=******;" Dim cmd As New MySqlCommand() Try Console.WriteLine("Connecting to MySQL...") conn.Open() cmd.Connection = conn cmd.CommandText = "DROP PROCEDURE IF EXISTS add_emp" cmd.ExecuteNonQuery() cmd.CommandText = "DROP TABLE IF EXISTS emp" cmd.ExecuteNonQuery() cmd.CommandText = "CREATE TABLE emp (empno INT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY, first_name VARCHAR(20), last_name VARCHAR(20), birthdate DATE)" cmd.ExecuteNonQuery() cmd.CommandText = "CREATE PROCEDURE add_emp(" & "IN fname VARCHAR(20), IN lname VARCHAR(20), IN bday DATETIME, OUT empno INT)" & "BEGIN INSERT INTO emp(first_name, last_name, birthdate) " & "VALUES(fname, lname, DATE(bday)); SET empno = LAST_INSERT_ID(); END" cmd.ExecuteNonQuery() Catch ex As MySqlException Console.WriteLine(("Error " & ex.Number & " has occurred: ") + ex.Message) End Try conn.Close() Console.WriteLine("Connection closed.") Try Console.WriteLine("Connecting to MySQL...") conn.Open() cmd.Connection = conn cmd.CommandText = "add_emp" cmd.CommandType = CommandType.StoredProcedure cmd.Parameters.AddWithValue("@lname", "Jones") cmd.Parameters("@lname").Direction = ParameterDirection.Input cmd.Parameters.AddWithValue("@fname", "Tom") cmd.Parameters("@fname").Direction = ParameterDirection.Input cmd.Parameters.AddWithValue("@bday", "1940-06-07") cmd.Parameters("@bday").Direction = ParameterDirection.Input cmd.Parameters.AddWithValue("@empno", MySqlDbType.Int32) cmd.Parameters("@empno").Direction = ParameterDirection.Output cmd.ExecuteNonQuery() Console.WriteLine("Employee number: " & cmd.Parameters("@empno").Value) Console.WriteLine("Birthday: " & cmd.Parameters("@bday").Value) Catch ex As MySql.Data.MySqlClient.MySqlException Console.WriteLine(("Error " & ex.Number & " has occurred: ") + ex.Message) End Try conn.Close() Console.WriteLine("Done.") End Sub End Module  File: manual.info, Node: connector-net-programming-blob, Next: connector-net-programming-crystal, Prev: connector-net-programming-stored, Up: connector-net-programming 21.2.5.13 Handling BLOB Data With Connector/NET ............................................... * Menu: * connector-net-programming-blob-serverprep:: Preparing the MySQL Server * connector-net-programming-blob-writing:: Writing a File to the Database * connector-net-programming-blob-reading:: Reading a BLOB from the Database to a File on Disk *Introduction* One common use for MySQL is the storage of binary data in *Note `BLOB': blob. columns. MySQL supports four different BLOB data types: *Note `TINYBLOB': blob, *Note `BLOB': blob, *Note `MEDIUMBLOB': blob, and *Note `LONGBLOB': blob. Data stored in a BLOB column can be accessed using Connector/NET and manipulated using client-side code. There are no special requirements for using Connector/NET with BLOB data. Simple code examples will be presented within this section, and a full sample application can be found in the `Samples' directory of the Connector/NET installation.  File: manual.info, Node: connector-net-programming-blob-serverprep, Next: connector-net-programming-blob-writing, Prev: connector-net-programming-blob, Up: connector-net-programming-blob 21.2.5.14 Preparing the MySQL Server .................................... The first step is using MySQL with BLOB data is to configure the server. Let's start by creating a table to be accessed. In my file tables, I usually have four columns: an AUTO_INCREMENT column of appropriate size (UNSIGNED SMALLINT) to serve as a primary key to identify the file, a VARCHAR column that stores the file name, an UNSIGNED MEDIUMINT column that stores the size of the file, and a MEDIUMBLOB column that stores the file itself. For this example, I will use the following table definition: CREATE TABLE file( file_id SMALLINT UNSIGNED AUTO_INCREMENT NOT NULL PRIMARY KEY, file_name VARCHAR(64) NOT NULL, file_size MEDIUMINT UNSIGNED NOT NULL, file MEDIUMBLOB NOT NULL); After creating a table, you may need to modify the max_allowed_packet system variable. This variable determines how large of a packet (that is, a single row) can be sent to the MySQL server. By default, the server will only accept a maximum size of 1MB from our client application. If you do not intend to exceed 1MB, this should be fine. If you do intend to exceed 1MB in your file transfers, this number has to be increased. The max_allowed_packet option can be modified using MySQL Administrator's Startup Variables screen. Adjust the Maximum permitted option in the Memory section of the Networking tab to an appropriate setting. After adjusting the value, click the `Apply Changes' button and restart the server using the `Service Control' screen of MySQL Administrator. You can also adjust this value directly in the my.cnf file (add a line that reads max_allowed_packet=xxM), or use the SET max_allowed_packet=xxM; syntax from within MySQL. Try to be conservative when setting max_allowed_packet, as transfers of BLOB data can take some time to complete. Try to set a value that will be adequate for your intended use and increase the value if necessary.  File: manual.info, Node: connector-net-programming-blob-writing, Next: connector-net-programming-blob-reading, Prev: connector-net-programming-blob-serverprep, Up: connector-net-programming-blob 21.2.5.15 Writing a File to the Database ........................................ To write a file to a database we need to convert the file to a byte array, then use the byte array as a parameter to an *Note `INSERT': insert. query. The following code opens a file using a FileStream object, reads it into a byte array, and inserts it into the `file' table: Visual Basic Example Dim conn As New MySqlConnection Dim cmd As New MySqlCommand Dim SQL As String Dim FileSize As UInt32 Dim rawData() As Byte Dim fs As FileStream conn.ConnectionString = "server=127.0.0.1;" _ & "uid=root;" _ & "pwd=12345;" _ & "database=test" Try fs = New FileStream("c:\image.png", FileMode.Open, FileAccess.Read) FileSize = fs.Length rawData = New Byte(FileSize) {} fs.Read(rawData, 0, FileSize) fs.Close() conn.Open() SQL = "INSERT INTO file VALUES(NULL, @FileName, @FileSize, @File)" cmd.Connection = conn cmd.CommandText = SQL cmd.Parameters.AddWithValue("@FileName", strFileName) cmd.Parameters.AddWithValue("@FileSize", FileSize) cmd.Parameters.AddWithValue("@File", rawData) cmd.ExecuteNonQuery() MessageBox.Show("File Inserted into database successfully!", _ "Success!", MessageBoxButtons.OK, MessageBoxIcon.Asterisk) conn.Close() Catch ex As Exception MessageBox.Show("There was an error: " & ex.Message, "Error", _ MessageBoxButtons.OK, MessageBoxIcon.Error) End Try C# Example MySql.Data.MySqlClient.MySqlConnection conn; MySql.Data.MySqlClient.MySqlCommand cmd; conn = new MySql.Data.MySqlClient.MySqlConnection(); cmd = new MySql.Data.MySqlClient.MySqlCommand(); string SQL; UInt32 FileSize; byte[] rawData; FileStream fs; conn.ConnectionString = "server=127.0.0.1;uid=root;" + "pwd=12345;database=test;"; try { fs = new FileStream(@"c:\image.png", FileMode.Open, FileAccess.Read); FileSize = fs.Length; rawData = new byte[FileSize]; fs.Read(rawData, 0, FileSize); fs.Close(); conn.Open(); SQL = "INSERT INTO file VALUES(NULL, @FileName, @FileSize, @File)"; cmd.Connection = conn; cmd.CommandText = SQL; cmd.Parameters.AddWithValue("@FileName", strFileName); cmd.Parameters.AddWithValue("@FileSize", FileSize); cmd.Parameters.AddWithValue("@File", rawData); cmd.ExecuteNonQuery(); MessageBox.Show("File Inserted into database successfully!", "Success!", MessageBoxButtons.OK, MessageBoxIcon.Asterisk); conn.Close(); } catch (MySql.Data.MySqlClient.MySqlException ex) { MessageBox.Show("Error " + ex.Number + " has occurred: " + ex.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error); } The `Read' method of the `FileStream' object is used to load the file into a byte array which is sized according to the `Length' property of the FileStream object. After assigning the byte array as a parameter of the `MySqlCommand' object, the `ExecuteNonQuery' method is called and the BLOB is inserted into the `file' table.  File: manual.info, Node: connector-net-programming-blob-reading, Prev: connector-net-programming-blob-writing, Up: connector-net-programming-blob 21.2.5.16 Reading a BLOB from the Database to a File on Disk ............................................................ Once a file is loaded into the `file' table, we can use the `MySqlDataReader' class to retrieve it. The following code retrieves a row from the `file' table, then loads the data into a `FileStream' object to be written to disk: Visual Basic Example Dim conn As New MySqlConnection Dim cmd As New MySqlCommand Dim myData As MySqlDataReader Dim SQL As String Dim rawData() As Byte Dim FileSize As UInt32 Dim fs As FileStream conn.ConnectionString = "server=127.0.0.1;" _ & "uid=root;" _ & "pwd=12345;" _ & "database=test" SQL = "SELECT file_name, file_size, file FROM file" Try conn.Open() cmd.Connection = conn cmd.CommandText = SQL myData = cmd.ExecuteReader If Not myData.HasRows Then Throw New Exception("There are no BLOBs to save") myData.Read() FileSize = myData.GetUInt32(myData.GetOrdinal("file_size")) rawData = New Byte(FileSize) {} myData.GetBytes(myData.GetOrdinal("file"), 0, rawData, 0, FileSize) fs = New FileStream("C:\newfile.png", FileMode.OpenOrCreate, FileAccess.Write) fs.Write(rawData, 0, FileSize) fs.Close() MessageBox.Show("File successfully written to disk!", "Success!", MessageBoxButtons.OK, MessageBoxIcon.Asterisk) myData.Close() conn.Close() Catch ex As Exception MessageBox.Show("There was an error: " & ex.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error) End Try C# Example MySql.Data.MySqlClient.MySqlConnection conn; MySql.Data.MySqlClient.MySqlCommand cmd; MySql.Data.MySqlClient.MySqlDataReader myData; conn = new MySql.Data.MySqlClient.MySqlConnection(); cmd = new MySql.Data.MySqlClient.MySqlCommand(); string SQL; UInt32 FileSize; byte[] rawData; FileStream fs; conn.ConnectionString = "server=127.0.0.1;uid=root;" + "pwd=12345;database=test;"; SQL = "SELECT file_name, file_size, file FROM file"; try { conn.Open(); cmd.Connection = conn; cmd.CommandText = SQL; myData = cmd.ExecuteReader(); if (! myData.HasRows) throw new Exception("There are no BLOBs to save"); myData.Read(); FileSize = myData.GetUInt32(myData.GetOrdinal("file_size")); rawData = new byte[FileSize]; myData.GetBytes(myData.GetOrdinal("file"), 0, rawData, 0, FileSize); fs = new FileStream(@"C:\newfile.png", FileMode.OpenOrCreate, FileAccess.Write); fs.Write(rawData, 0, FileSize); fs.Close(); MessageBox.Show("File successfully written to disk!", "Success!", MessageBoxButtons.OK, MessageBoxIcon.Asterisk); myData.Close(); conn.Close(); } catch (MySql.Data.MySqlClient.MySqlException ex) { MessageBox.Show("Error " + ex.Number + " has occurred: " + ex.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error); } After connecting, the contents of the `file' table are loaded into a `MySqlDataReader' object. The `GetBytes' method of the MySqlDataReader is used to load the BLOB into a byte array, which is then written to disk using a FileStream object. The `GetOrdinal' method of the MySqlDataReader can be used to determine the integer index of a named column. Use of the GetOrdinal method prevents errors if the column order of the *Note `SELECT': select. query is changed.  File: manual.info, Node: connector-net-programming-crystal, Next: connector-net-programming-datetime, Prev: connector-net-programming-blob, Up: connector-net-programming 21.2.5.17 Using Connector/NET with Crystal Reports .................................................. * Menu: * connector-net-programming-crystal-source:: Creating a Data Source * connector-net-programming-crystal-creating:: Creating the Report * connector-net-programming-crystal-displaying:: Displaying the Report *Introduction* Crystal Reports is a common tool used by Windows application developers to perform reporting and document generation. In this section we will show how to use Crystal Reports XI with MySQL and Connector/NET.  File: manual.info, Node: connector-net-programming-crystal-source, Next: connector-net-programming-crystal-creating, Prev: connector-net-programming-crystal, Up: connector-net-programming-crystal 21.2.5.18 Creating a Data Source ................................ When creating a report in Crystal Reports there are two options for accessing the MySQL data while designing your report. The first option is to use Connector/ODBC as an ADO data source when designing your report. You will be able to browse your database and choose tables and fields using drag and drop to build your report. The disadvantage of this approach is that additional work must be performed within your application to produce a data set that matches the one expected by your report. The second option is to create a data set in VB.NET and save it as XML. This XML file can then be used to design a report. This works quite well when displaying the report in your application, but is less versatile at design time because you must choose all relevant columns when creating the data set. If you forget a column you must re-create the data set before the column can be added to the report. The following code can be used to create a data set from a query and write it to disk: Visual Basic Example Dim myData As New DataSet Dim conn As New MySqlConnection Dim cmd As New MySqlCommand Dim myAdapter As New MySqlDataAdapter conn.ConnectionString = "server=127.0.0.1;" _ & "uid=root;" _ & "pwd=12345;" _ & "database=world" Try conn.Open() cmd.CommandText = "SELECT city.name AS cityName, city.population AS CityPopulation, " _ & "country.name, country.population, country.continent " _ & "FROM country, city ORDER BY country.continent, country.name" cmd.Connection = conn myAdapter.SelectCommand = cmd myAdapter.Fill(myData) myData.WriteXml("C:\dataset.xml", XmlWriteMode.WriteSchema) Catch ex As Exception MessageBox.Show(ex.Message, "Report could not be created", MessageBoxButtons.OK, MessageBoxIcon.Error) End Try C# Example DataSet myData = new DataSet(); MySql.Data.MySqlClient.MySqlConnection conn; MySql.Data.MySqlClient.MySqlCommand cmd; MySql.Data.MySqlClient.MySqlDataAdapter myAdapter; conn = new MySql.Data.MySqlClient.MySqlConnection(); cmd = new MySql.Data.MySqlClient.MySqlCommand(); myAdapter = new MySql.Data.MySqlClient.MySqlDataAdapter(); conn.ConnectionString = "server=127.0.0.1;uid=root;" + "pwd=12345;database=test;"; try { cmd.CommandText = "SELECT city.name AS cityName, city.population AS CityPopulation, " + "country.name, country.population, country.continent " + "FROM country, city ORDER BY country.continent, country.name"; cmd.Connection = conn; myAdapter.SelectCommand = cmd; myAdapter.Fill(myData); myData.WriteXml(@"C:\dataset.xml", XmlWriteMode.WriteSchema); } catch (MySql.Data.MySqlClient.MySqlException ex) { MessageBox.Show(ex.Message, "Report could not be created", MessageBoxButtons.OK, MessageBoxIcon.Error); } The resulting XML file can be used as an ADO.NET XML datasource when designing your report. If you choose to design your reports using Connector/ODBC, it can be downloaded from dev.mysql.com (http://dev.mysql.com/downloads/connector/odbc/3.51.html).  File: manual.info, Node: connector-net-programming-crystal-creating, Next: connector-net-programming-crystal-displaying, Prev: connector-net-programming-crystal-source, Up: connector-net-programming-crystal 21.2.5.19 Creating the Report ............................. For most purposes the Standard Report wizard should help with the initial creation of a report. To start the wizard, open Crystal Reports and choose the New > Standard Report option from the File menu. The wizard will first prompt you for a data source. If you are using Connector/ODBC as your data source, use the OLEDB provider for ODBC option from the OLE DB (ADO) tree instead of the ODBC (RDO) tree when choosing a data source. If using a saved data set, choose the ADO.NET (XML) option and browse to your saved data set. The remainder of the report creation process is done automatically by the wizard. After the report is created, choose the Report Options... entry of the File menu. Un-check the Save Data With Report option. This prevents saved data from interfering with the loading of data within our application.  File: manual.info, Node: connector-net-programming-crystal-displaying, Prev: connector-net-programming-crystal-creating, Up: connector-net-programming-crystal 21.2.5.20 Displaying the Report ............................... To display a report we first populate a data set with the data needed for the report, then load the report and bind it to the data set. Finally we pass the report to the crViewer control for display to the user. The following references are needed in a project that displays a report: * CrystalDecisions.CrystalReports.Engine * CrystalDecisions.ReportSource * CrystalDecisions.Shared * CrystalDecisions.Windows.Forms The following code assumes that you created your report using a data set saved using the code shown in *Note connector-net-programming-crystal-source::, and have a crViewer control on your form named `myViewer'. Visual Basic Example Imports CrystalDecisions.CrystalReports.Engine Imports System.Data Imports MySql.Data.MySqlClient Dim myReport As New ReportDocument Dim myData As New DataSet Dim conn As New MySqlConnection Dim cmd As New MySqlCommand Dim myAdapter As New MySqlDataAdapter conn.ConnectionString = _ "server=127.0.0.1;" _ & "uid=root;" _ & "pwd=12345;" _ & "database=test" Try conn.Open() cmd.CommandText = "SELECT city.name AS cityName, city.population AS CityPopulation, " _ & "country.name, country.population, country.continent " _ & "FROM country, city ORDER BY country.continent, country.name" cmd.Connection = conn myAdapter.SelectCommand = cmd myAdapter.Fill(myData) myReport.Load(".\world_report.rpt") myReport.SetDataSource(myData) myViewer.ReportSource = myReport Catch ex As Exception MessageBox.Show(ex.Message, "Report could not be created", MessageBoxButtons.OK, MessageBoxIcon.Error) End Try C# Example using CrystalDecisions.CrystalReports.Engine; using System.Data; using MySql.Data.MySqlClient; ReportDocument myReport = new ReportDocument(); DataSet myData = new DataSet(); MySql.Data.MySqlClient.MySqlConnection conn; MySql.Data.MySqlClient.MySqlCommand cmd; MySql.Data.MySqlClient.MySqlDataAdapter myAdapter; conn = new MySql.Data.MySqlClient.MySqlConnection(); cmd = new MySql.Data.MySqlClient.MySqlCommand(); myAdapter = new MySql.Data.MySqlClient.MySqlDataAdapter(); conn.ConnectionString = "server=127.0.0.1;uid=root;" + "pwd=12345;database=test;"; try { cmd.CommandText = "SELECT city.name AS cityName, city.population AS CityPopulation, " + "country.name, country.population, country.continent " + "FROM country, city ORDER BY country.continent, country.name"; cmd.Connection = conn; myAdapter.SelectCommand = cmd; myAdapter.Fill(myData); myReport.Load(@".\world_report.rpt"); myReport.SetDataSource(myData); myViewer.ReportSource = myReport; } catch (MySql.Data.MySqlClient.MySqlException ex) { MessageBox.Show(ex.Message, "Report could not be created", MessageBoxButtons.OK, MessageBoxIcon.Error); } A new data set it generated using the same query used to generate the previously saved data set. Once the data set is filled, a ReportDocument is used to load the report file and bind it to the data set. The ReportDocument is the passed as the ReportSource of the crViewer. This same approach is taken when a report is created from a single table using Connector/ODBC. The data set replaces the table used in the report and the report is displayed properly. When a report is created from multiple tables using Connector/ODBC, a data set with multiple tables must be created in our application. This enables each table in the report data source to be replaced with a report in the data set. We populate a data set with multiple tables by providing multiple *Note `SELECT': select. statements in our MySqlCommand object. These *Note `SELECT': select. statements are based on the SQL query shown in Crystal Reports in the Database menu's Show SQL Query option. Assume the following query: SELECT `country`.`Name`, `country`.`Continent`, `country`.`Population`, `city`.`Name`, `city`.`Population` FROM `world`.`country` `country` LEFT OUTER JOIN `world`.`city` `city` ON `country`.`Code`=`city`.`CountryCode` ORDER BY `country`.`Continent`, `country`.`Name`, `city`.`Name` This query is converted to two *Note `SELECT': select. queries and displayed with the following code: Visual Basic Example Imports CrystalDecisions.CrystalReports.Engine Imports System.Data Imports MySql.Data.MySqlClient Dim myReport As New ReportDocument Dim myData As New DataSet Dim conn As New MySqlConnection Dim cmd As New MySqlCommand Dim myAdapter As New MySqlDataAdapter conn.ConnectionString = "server=127.0.0.1;" _ & "uid=root;" _ & "pwd=12345;" _ & "database=world" Try conn.Open() cmd.CommandText = "SELECT name, population, countrycode FROM city ORDER BY countrycode, name; " _ & "SELECT name, population, code, continent FROM country ORDER BY continent, name" cmd.Connection = conn myAdapter.SelectCommand = cmd myAdapter.Fill(myData) myReport.Load(".\world_report.rpt") myReport.Database.Tables(0).SetDataSource(myData.Tables(0)) myReport.Database.Tables(1).SetDataSource(myData.Tables(1)) myViewer.ReportSource = myReport Catch ex As Exception MessageBox.Show(ex.Message, "Report could not be created", MessageBoxButtons.OK, MessageBoxIcon.Error) End Try C# Example using CrystalDecisions.CrystalReports.Engine; using System.Data; using MySql.Data.MySqlClient; ReportDocument myReport = new ReportDocument(); DataSet myData = new DataSet(); MySql.Data.MySqlClient.MySqlConnection conn; MySql.Data.MySqlClient.MySqlCommand cmd; MySql.Data.MySqlClient.MySqlDataAdapter myAdapter; conn = new MySql.Data.MySqlClient.MySqlConnection(); cmd = new MySql.Data.MySqlClient.MySqlCommand(); myAdapter = new MySql.Data.MySqlClient.MySqlDataAdapter(); conn.ConnectionString = "server=127.0.0.1;uid=root;" + "pwd=12345;database=test;"; try { cmd.CommandText = "SELECT name, population, countrycode FROM city ORDER " + "BY countrycode, name; *Note `SELECT': select. name, population, code, continent FROM " + "country ORDER BY continent, name"; cmd.Connection = conn; myAdapter.SelectCommand = cmd; myAdapter.Fill(myData); myReport.Load(@".\world_report.rpt"); myReport.Database.Tables(0).SetDataSource(myData.Tables(0)); myReport.Database.Tables(1).SetDataSource(myData.Tables(1)); myViewer.ReportSource = myReport; } catch (MySql.Data.MySqlClient.MySqlException ex) { MessageBox.Show(ex.Message, "Report could not be created", MessageBoxButtons.OK, MessageBoxIcon.Error); } It is important to order the *Note `SELECT': select. queries in alphabetic order, as this is the order the report will expect its source tables to be in. One SetDataSource statement is needed for each table in the report. This approach can cause performance problems because Crystal Reports must bind the tables together on the client-side, which will be slower than using a pre-saved data set.  File: manual.info, Node: connector-net-programming-datetime, Next: connector-net-programming-asp-provider, Prev: connector-net-programming-crystal, Up: connector-net-programming 21.2.5.21 Handling Date and Time Information in Connector/NET ............................................................. * Menu: * connector-net-programming-datetime-problems:: Problems when Using Invalid Dates * connector-net-programming-datetime-restricting:: Restricting Invalid Dates * connector-net-programming-datetime-invalid:: Handling Invalid Dates * connector-net-programming-datetime-null:: Handling NULL Dates *Introduction* MySQL and the .NET languages handle date and time information differently, with MySQL allowing dates that cannot be represented by a .NET data type, such as '`0000-00-00 00:00:00''. These differences can cause problems if not properly handled. In this section we will demonstrate how to properly handle date and time information when using Connector/NET.  File: manual.info, Node: connector-net-programming-datetime-problems, Next: connector-net-programming-datetime-restricting, Prev: connector-net-programming-datetime, Up: connector-net-programming-datetime 21.2.5.22 Problems when Using Invalid Dates ........................................... The differences in date handling can cause problems for developers who use invalid dates. Invalid MySQL dates cannot be loaded into native .NET `DateTime' objects, including `NULL' dates. Because of this issue, .NET `DataSet' objects cannot be populated by the `Fill' method of the `MySqlDataAdapter' class as invalid dates will cause a `System.ArgumentOutOfRangeException' exception to occur.  File: manual.info, Node: connector-net-programming-datetime-restricting, Next: connector-net-programming-datetime-invalid, Prev: connector-net-programming-datetime-problems, Up: connector-net-programming-datetime 21.2.5.23 Restricting Invalid Dates ................................... The best solution to the date problem is to restrict users from entering invalid dates. This can be done on either the client or the server side. Restricting invalid dates on the client side is as simple as always using the .NET `DateTime' class to handle dates. The `DateTime' class will only allow valid dates, ensuring that the values in your database are also valid. The disadvantage of this is that it is not useful in a mixed environment where .NET and non .NET code are used to manipulate the database, as each application must perform its own date validation. Users of MySQL 5.0.2 and higher can use the new `traditional' SQL mode to restrict invalid date values. For information on using the `traditional' SQL mode, see *Note server-sql-mode::.  File: manual.info, Node: connector-net-programming-datetime-invalid, Next: connector-net-programming-datetime-null, Prev: connector-net-programming-datetime-restricting, Up: connector-net-programming-datetime 21.2.5.24 Handling Invalid Dates ................................ Although it is strongly recommended that you avoid the use of invalid dates within your .NET application, it is possible to use invalid dates by means of the `MySqlDateTime' data type. The `MySqlDateTime' data type supports the same date values that are supported by the MySQL server. The default behavior of Connector/NET is to return a .NET DateTime object for valid date values, and return an error for invalid dates. This default can be modified to cause Connector/NET to return `MySqlDateTime' objects for invalid dates. To instruct Connector/NET to return a `MySqlDateTime' object for invalid dates, add the following line to your connection string: Allow Zero Datetime=True Please note that the use of the `MySqlDateTime' class can still be problematic. The following are some known issues: 1. Data binding for invalid dates can still cause errors (zero dates like 0000-00-00 do not seem to have this problem). 2. The `ToString' method return a date formatted in the standard MySQL format (for example, `2005-02-23 08:50:25'). This differs from the `ToString' behavior of the .NET DateTime class. 3. The `MySqlDateTime' class supports NULL dates, while the .NET DateTime class does not. This can cause errors when trying to convert a MySQLDateTime to a DateTime if you do not check for NULL first. Because of the known issues, the best recommendation is still to use only valid dates in your application.  File: manual.info, Node: connector-net-programming-datetime-null, Prev: connector-net-programming-datetime-invalid, Up: connector-net-programming-datetime 21.2.5.25 Handling NULL Dates ............................. The .NET `DateTime' data type cannot handle `NULL' values. As such, when assigning values from a query to a `DateTime' variable, you must first check whether the value is in fact `NULL'. When using a `MySqlDataReader', use the `.IsDBNull' method to check whether a value is `NULL' before making the assignment: Visual Basic Example If Not myReader.IsDBNull(myReader.GetOrdinal("mytime")) Then myTime = myReader.GetDateTime(myReader.GetOrdinal("mytime")) Else myTime = DateTime.MinValue End If C# Example if (! myReader.IsDBNull(myReader.GetOrdinal("mytime"))) myTime = myReader.GetDateTime(myReader.GetOrdinal("mytime")); else myTime = DateTime.MinValue; `NULL' values will work in a data set and can be bound to form controls without special handling.  File: manual.info, Node: connector-net-programming-asp-provider, Next: connector-net-programming-binary-issues, Prev: connector-net-programming-datetime, Up: connector-net-programming 21.2.5.26 ASP.NET Provider Model ................................ MySQL Connector/NET provides support for the ASP.NET 2.0 provider model. This model enables application developers to focus on the business logic of their application instead of having to recreate such boilerplate items as membership and roles support. MySQL Connector/NET supplies the following providers: * Membership Provider * Role Provider * Profile Provider * Session State Provider (MySQL Connector/NET 6.1 and later) The following tables show the supported providers, their default provider and the corresponding MySQL provider. *Membership Provider* Default Provider MySQL Provider System.Web.Security.SqlMembershipProviderMySql.Web.Security.MySQLMembershipProvider *Role Provider* Default Provider MySQL Provider System.Web.Security.SqlRoleProvider MySql.Web.Security.MySQLRoleProvider *Profile Provider* Default Provider MySQL Provider System.Web.Profile.SqlProfileProviderMySql.Web.Profile.MySQLProfileProvider *SessionState Provider* Default Provider MySQL Provider System.Web.SessionState.InProcSessionStateStoreMySql.Web.SessionState.MySqlSessionStateStore *Note*: The MySQL Session State provider uses slightly different capitalization on the class name compared to the other MySQL providers. *Installing The Providers* The installation of Connector/Net 5.1 or later will install the providers and register them in your machine's .NET configuration file, `machine.config'. The additional entries created will result in the `system.web' section appearing similar to the following code: Each provider type can have multiple provider implementations. The default provider can also be set here using the `defaultProvider' attribute, but usually this is set in the `web.config' file either manually or by using the ASP.NET configuration tool. At time of writing the `MySqlSessionStateStore' is not added to `machine.config' at install time, and so you would need to add the following: It should be pointed out that the SessionState Provider uses the `customProvider' attribute, rather than `defaultProvider', to set the provider as the default. A typical `web.config' file might contain: ... This sets the MySQL Providers as the defaults to be used in this web application. The providers are implemented in the file `mysql.web.dll' and this file can be found in your MySQL Connector/NET installation folder. There is no need to run any type of SQL script to set up the database schema as the providers create and maintain the proper schema automatically. * Using The Providers* The easiest way to start using the providers is to use the ASP.NET configuration tool that is available on the Solution Explorer toolbar when you have a website project loaded. In the web pages that open you will be able to select the MySQL membership and roles providers by indicating that you want to pick a custom provider for each area. When the provider is installed, it creates a dummy connection string named `LocalMySqlServer'. This has to be done so that the provider will work in the ASP.NET configuration tool. However, you will want to override this connection string in your `web.config' file. You do this by first removing the dummy connection string and then adding in the proper one, as shown in the following example: Note the database you want to connect to must be specified. Rather than manually editing configuration files it is recommended that you use the MySQL Website Configuration tool to config your desired provider setup. From MySQL Connector/NET 6.1.1 onwards all providers can be selected and configured from this wizard. The tool will modify your `website.config' file to the desired configuration. A tutorial on doing this is available in the following section *Note connector-net-website-config::. A tutorial demonstrating how to use the Membership and Role Providers can be found in the following section *Note connector-net-tutorials-asp-roles::. * Deployment* To use the providers on a production server you will need to distribute the `MySql.Data' and the `MySql.Web' assemblies and either register them in the remote systems Global Assembly Cache or keep them in your application's `bin/' directory.  File: manual.info, Node: connector-net-programming-binary-issues, Next: connector-using-character-sets, Prev: connector-net-programming-asp-provider, Up: connector-net-programming 21.2.5.27 Binary/Nonbinary Issues ................................. There are certain situations where MySQL will return incorrect metadata about one or more columns. More specifically, the server will sometimes report that a column is binary when it is not and vice versa. In these situations, it becomes practically impossible for the connector to be able to correctly identify the correct metadat. Some examples of situations that may return incorrect metadata are: * Execution of *Note `SHOW PROCESSLIST': show-processlist. Some of the columns will be returned as binary even though they only hold string data. * When a temp table is used to process a resultset, some columns may be returned with incorrect binary flags. * Some server functions such `DATE_FORMAT' will incorrectly return the column as binary. With the availability of `BINARY' and `VARBINARY' data types it is important that we respect the metadata returned by the sever. However, we are aware that some existing applications may break with this change so we are creating a connection string option to enable or disable it. By default, Connector/Net 5.1 will respect the binary flags returned by the server. This will mean that you may need to make small changes to your application to accommodate this change. In the event that the changes required to your application would be too large, you can add 'respect binary flags=false' to your connection string. This will cause the connector to use the prior behavior. In a nutshell, that behavior was that any column that is marked as string, regardless of binary flags, will be returned as string. Only columns that are specifically marked as a `BLOB' will be returned as `BLOB'.  File: manual.info, Node: connector-using-character-sets, Next: content-advanced-topics-medium-trust, Prev: connector-net-programming-binary-issues, Up: connector-net-programming 21.2.5.28 Character Sets ........................ *Treating Binary Blobs As UTF8* MySQL doesn't currently support 4 byte UTF8 sequences. This makes it difficult to represent some multi-byte languages such as Japanese. To try and alleviate this, Connector/Net now supports a mode where binary blobs can be treated as strings. To do this, you set the 'Treat Blobs As UTF8' connection string keyword to yes. This is all that needs to be done to enable conversion of all binary blobs to UTF8 strings. If you wish to convert only some of your blob columns, then you can make use of the 'BlobAsUTF8IncludePattern' and 'BlobAsUTF8ExcludePattern' keywords. These should be set to the regular expression pattern that matches the column names you wish to include or exclude respectively. One thing to note is that the regular expression patterns can both match a single column. When this happens, the include pattern is applied before the exclude pattern. The result, in this case, would be that the column would be excluded. You should also be aware that this mode does not apply to columns of type `BINARY' or `VARBINARY' and also do not apply to nonbinary `BLOB' columns. Currently this mode only applies to reading strings out of MySQL. To insert 4-byte UTF8 strings into blob columns you will need to use the .NET `Encoding.GetBytes' function to convert your string to a series of bytes. You can then set this byte array as a parameter for a `BLOB' column.  File: manual.info, Node: content-advanced-topics-medium-trust, Next: connector-net-programming-tracing, Prev: connector-using-character-sets, Up: connector-net-programming 21.2.5.29 Working with medium trust ................................... .NET applications operate under a given trust level. Normal desktop applications operate under full trust while web applications that are hosted in shared environments are normally run under the medium trust level. Some hosting providers host shared applications in their own app pools and allow the application to run under full trust, but this seems to be the exception rather than the rule. Connector/Net versions prior to 5.0.8 and 5.1.3 were not compatible with medium trust hosting. Starting with these versions, Connector/Net can be used under medium trust hosting that has been modified to allow the use of sockets for communication. By default, medium trust does not include `SocketPermission'. Connector/Net uses sockets to talk with the MySQL server so it is required that a new trust level be created that is an exact clone of medium trust but that has `SocketPermission' added.  File: manual.info, Node: connector-net-programming-tracing, Next: connector-net-programming-bulk-loader, Prev: content-advanced-topics-medium-trust, Up: connector-net-programming 21.2.5.30 Using the MySQL Connector/NET Trace Source Object ........................................................... * Menu: * connector-net-programming-tracing-mysql:: Viewing MySQL Trace Information * connector-net-programming-tracing-mysql-custom-listeners:: Building Custom Listeners MySQL Connector/NET 6.2 introduced support for .NET 2.0 compatible tracing, using `TraceSource' objects. The .NET 2.0 tracing architecture consists of four main parts: * _Source_ - This is the originator of the trace information. The source is used to send trace messages. The name of the source provided by MySQL Connector/NET is `mysql'. * _Switch_ - This defines the level of trace information to emit. Typically, this is specified in the `app.config' file, so that it is not necessary to recompile an application to change the trace level. * _Listener_ - Trace listeners define where the trace information will be written to. Supported listeners include, for example, the Visual Studio Output window, the Windows Event Log, and the console. * _Filter_ - Filters can be attached to listeners. Filters determine the level of trace information that will be written. While a switch defines the level of information that will be written to all listeners, a filter can be applied on a per-listener basis, giving finer grained control of trace information. To use tracing a `TraceSource' object first needs to be created. To create a `TraceSource' object in MySQL Connector/NET you would use code similar to the following: TraceSource ts = new TraceSource("mysql"); To enable trace messages you also need to configure a trace switch. There are three main switch classes, `BooleanSwitch', `SourceSwitch', and `TraceSwitch'. Trace switches also have associated with them a trace level enumeration, these are `Off', `Error', `Warning', `Info', and `Verbose'. The following code snippet illustrates creating a switch: ts.Switch = new SourceSwitch("MySwitch", "Verbose"); This creates a `SourceSwitch', called `MySwitch', and sets the trace level to `Verbose', meaning that all trace messages will be written. It is convenient to be able to change the trace level without having to recompile the code. This is achieved by specifying the trace level in application configuration file, `app.config'. You then simply need to specify the desired trace level in the configuration file and restart the application. The trace source is configured within the `system.diagnostics' section of the file. The following XML snippet illustrates this: ... ... ... ... By default trace information is written to the Output window of Microsoft Visual Studio. However, there are a wide range of listeners than can be attached to the trace source, so that trace messages can be written out to various destinations. It is also possible to create custom listeners to allow trace messages to be written to other destinations as mobile devices and web services. A commonly used example of a listener is `ConsoleTraceListener', which writes trace messages to the console. To add a listener at run time you can use code such as the following: ts.Listeners.Add(new ConsoleTraceListener()); You can then call methods on trace source object to generate trace information. For example, the `TraceInformation()', `TraceEvent()', or `TraceData()' methods can be used. The `TraceInformation()' method simply prints a string passed as a parameter. The `TraceEvent()' method, as well as the optional informational string, requires a `TraceEventType' value to be passed to indicate the trace message type, and also an application specific ID. The `TraceEventType' can have a value of `Verbose', `Information', `Warning', `Error', and `Critical'. Using the `TraceData()' method you can pass any object, for example an exception object, instead of a message. To ensure than these generated trace messages gets flushed from the trace source buffers to listeners, you need to invoke the `Flush()' method. When you are finished using a trace source, you should call the `Close()' method. The `Close()' method first calls `Flush()', to ensure any remaining data is written out. It then frees up resources, and closes the listeners associated with the trace source. ts.TraceInformation("Informational message"); ts.TraceEvent(TraceEventType.Error, 3, "Optional error message"); ts.TraceData(TraceEventType.Error, 3, ex); // pass exception object ts.Flush(); ... ts.Close();  File: manual.info, Node: connector-net-programming-tracing-mysql, Next: connector-net-programming-tracing-mysql-custom-listeners, Prev: connector-net-programming-tracing, Up: connector-net-programming-tracing 21.2.5.31 Viewing MySQL Trace Information ......................................... This section describes how to set up your application to view MySQL trace information. The first thing you need to do is create a suitable `app.config' file for your application. An example is shown in the following code: This ensures a suitable trace source is created, along with a switch. The switch level in this case is set to `Verbose' to display the maximum amount of information. In the application the only other step required is to add `logging=true' to the connection string. An example application could be: using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Diagnostics; using MySql.Data; using MySql.Data.MySqlClient; using MySql.Web; namespace ConsoleApplication1 { class Program { static void Main(string[] args) { string connStr = "server=localhost;user=root;database=world;port=3306;password=******;logging=true;"; MySqlConnection conn = new MySqlConnection(connStr); try { Console.WriteLine("Connecting to MySQL..."); conn.Open(); string sql = "SELECT Name, HeadOfState FROM Country WHERE Continent='Oceania'"; MySqlCommand cmd = new MySqlCommand(sql, conn); MySqlDataReader rdr = cmd.ExecuteReader(); while (rdr.Read()) { Console.WriteLine(rdr[0] + " -- " + rdr[1]); } rdr.Close(); conn.Close(); } catch (Exception ex) { Console.WriteLine(ex.ToString()); } Console.WriteLine("Done."); } } } This simple application will then generate the following output: Connecting to MySQL... mysql Information: 1 : 1: Connection Opened: connection string = 'server=localhost;User Id=root;database=world;port=3306 ;password=******;logging=True' mysql Information: 3 : 1: Query Opened: SHOW VARIABLES mysql Information: 4 : 1: Resultset Opened: field(s) = 2, affected rows = -1, inserted id = -1 mysql Information: 5 : 1: Resultset Closed. Total rows=272, skipped rows=0, size (bytes)=7058 mysql Information: 6 : 1: Query Closed mysql Information: 3 : 1: Query Opened: SHOW COLLATION mysql Information: 4 : 1: Resultset Opened: field(s) = 6, affected rows = -1, inserted id = -1 mysql Information: 5 : 1: Resultset Closed. Total rows=127, skipped rows=0, size (bytes)=4102 mysql Information: 6 : 1: Query Closed mysql Information: 3 : 1: Query Opened: SET character_set_results=NULL mysql Information: 4 : 1: Resultset Opened: field(s) = 0, affected rows = 0, inserted id = 0 mysql Information: 5 : 1: Resultset Closed. Total rows=0, skipped rows=0, size (bytes)=0 mysql Information: 6 : 1: Query Closed mysql Information: 10 : 1: Set Database: world mysql Information: 3 : 1: Query Opened: SELECT Name, HeadOfState FROM Country WHERE Continent='Oceania' mysql Information: 4 : 1: Resultset Opened: field(s) = 2, affected rows = -1, inserted id = -1 American Samoa -- George W. Bush Australia -- Elisabeth II ... Wallis and Futuna -- Jacques Chirac Vanuatu -- John Bani United States Minor Outlying Islands -- George W. Bush mysql Information: 5 : 1: Resultset Closed. Total rows=28, skipped rows=0, size (bytes)=788 mysql Information: 6 : 1: Query Closed Done. mysql Information: 2 : 1: Connection Closed The first number displayed in the trace message corresponds to the MySQL event type: Event Description 1 ConnectionOpened: connection string 2 ConnectionClosed: 3 QueryOpened: mysql server thread id, query text 4 ResultOpened: field count, affected rows (-1 if select), inserted id (-1 if select) 5 ResultClosed: total rows read, rows skipped, size of resultset in bytes 6 QueryClosed: 7 StatementPrepared: prepared sql, statement id 8 StatementExecuted: statement id, mysql server thread id 9 StatementClosed: statement id 10 NonQuery: [varies] 11 UsageAdvisorWarning: usage advisor flag. NoIndex = 1, BadIndex = 2, SkippedRows = 3, SkippedColumns = 4, FieldConversion = 5. 12 Warning: level, code, message 13 Error: error number, error message The second number displayed in the trace message is the connection count. Although this example uses the `ConsoleTraceListener', any of the other standard listeners could have been used. Another possibility is to create a custom listener that uses the information passed using the `TraceEvent' method. For example, a custom trace listener could be created to perform active monitoring of the MySQL event messages, rather than simply writing these to an output device. It is also possible to add listeners to the MySQL Trace Source at run time. This can be done with the following code: MySqlTrace.Listeners.Add(new ConsoleTraceListener()); MySQL Connector/NET 6.3.2 introduced the ability to switch tracing on and off at run time. This can be achieved using the calls `MySqlTrace.EnableQueryAnalyzer(string host, int postInterval)' and `MySqlTrace.DisableQueryAnalyzer()'. The parameter `host' is the URL of the MySQL Enterprise Monitor server to monitor. The parameter `postInterval' is how often the data should be periodically posted to MySQL Enterprise Monitor, in seconds.  File: manual.info, Node: connector-net-programming-tracing-mysql-custom-listeners, Prev: connector-net-programming-tracing-mysql, Up: connector-net-programming-tracing 21.2.5.32 Building Custom Listeners ................................... To build custom listeners that work with the MySQL Connector/NET Trace Source, it is necessary to understand the key methods used, and the event data formats used. The main method involved in passing trace messages is the `TraceSource.TraceEvent' method. This has the prototype: public void TraceEvent( TraceEventType eventType, int id, string format, params Object[] args ) This trace source method will process the list of attached listeners and call the listener's TraceListener.TraceEvent method. The prototype for the `TraceListener.TraceEvent' method is as follows: public virtual void TraceEvent( TraceEventCache eventCache, string source, TraceEventType eventType, int id, string format, params Object[] args ) The first three parameters are used in the standard as defined by Microsoft (http://msdn.microsoft.com/en-us/library/d193webf.aspx). The last three parameters contain MySQL-specific trace information. Each of these parameters is now discussed in more detail. *`int id'* This is a MySQL-specific identifier. It identifies the MySQL event type that has occurred, resulting in a trace message being generated. This value is defined by the `MySqlTraceEventType' public enum contained in the MySQL Connector/NET code: public enum MySqlTraceEventType : int { ConnectionOpened = 1, ConnectionClosed, QueryOpened, ResultOpened, ResultClosed, QueryClosed, StatementPrepared, StatementExecuted, StatementClosed, NonQuery, UsageAdvisorWarning, Warning, Error } The MySQL event type also determines the contents passed using the parameter `params Object[] args'. The nature of the `args' parameters are described in further detail in the following material. *`string format'* This is the format string that contains zero or more format items, which correspond to objects in the args array. This would be used by a listener such as `ConsoleTraceListener' to write a message to the output device. *`params Object[] args'* This is a list of objects that depends on the MySQL event type, `id'. However, the first parameter passed using this list is always the driver id. The driver id is a unique number that is incremented each time the connector is opened. This enables groups of queries on the same connection to be identified. The parameters that follow driver id depend of the MySQL event id, and are as follows: MySQL-specific event Arguments (params Object[] args) type ConnectionOpened Connection string ConnectionClosed No additional parameters QueryOpened mysql server thread id, query text ResultOpened field count, affected rows (-1 if select), inserted id (-1 if select) ResultClosed total rows read, rows skipped, size of resultset in bytes QueryClosed No additional parameters StatementPrepared prepared sql, statement id StatementExecuted statement id, mysql server thread id StatementClosed statement id NonQuery Varies UsageAdvisorWarning usage advisor flag. NoIndex = 1, BadIndex = 2, SkippedRows = 3, SkippedColumns = 4, FieldConversion = 5. Warning level, code, message Error error number, error message This information will allow you to create custom trace listeners that can actively monitor the MySQL-specific events.  File: manual.info, Node: connector-net-programming-bulk-loader, Prev: connector-net-programming-tracing, Up: connector-net-programming 21.2.5.33 Using the Bulk Loader ............................... MySQL Connector/NET features a bulk loader class that wraps the MySQL statement `LOAD DATA INFILE'. This gives MySQL Connector/NET the ability to load a data file from a local or remote host to the server. The class concerned is `MySqlBulkLoader'. This class has various methods, the main one being `load' to cause the specified file to be loaded to the server. Various parameters can be set to control how the data file is processed. This is achieved through setting various properties of the class. For example, the field separator used, such as comma or tab, can be specified, along with the record terminator, such as newline. The following code shows a simple example of using the `MySqlBulkLoader' class. First an empty table needs to be created, in this case in the `test' database: CREATE TABLE Career ( Name VARCHAR(100) NOT NULL, Age INTEGER, Profession VARCHAR(200) ); A simple tab-delimited data file is also created (it could use any other field delimiter such as comma): Table Career in Test Database Name Age Profession Tony 47 Technical Writer Ana 43 Nurse Fred 21 IT Specialist Simon 45 Hairy Biker Note that with this test file the first three lines will need to be ignored, as they do not contain table data. This can be achieved using the `NumberOfLinesToSkip' property. This file can then be loaded and used to populate the `Career' table in the `test' database: using System; using System.Text; using MySql.Data; using MySql.Data.MySqlClient; namespace ConsoleApplication1 { class Program { static void Main(string[] args) { string connStr = "server=localhost;user=root;database=test;port=3306;password=******;"; MySqlConnection conn = new MySqlConnection(connStr); MySqlBulkLoader bl = new MySqlBulkLoader(conn); bl.TableName = "Career"; bl.FieldTerminator = "\t"; bl.LineTerminator = "\n"; bl.FileName = "c:/career_data.txt"; bl.NumberOfLinesToSkip = 3; try { Console.WriteLine("Connecting to MySQL..."); conn.Open(); // Upload data from file int count = bl.Load(); Console.WriteLine(count + " lines uploaded."); string sql = "SELECT Name, Age, Profession FROM Career"; MySqlCommand cmd = new MySqlCommand(sql, conn); MySqlDataReader rdr = cmd.ExecuteReader(); while (rdr.Read()) { Console.WriteLine(rdr[0] + " -- " + rdr[1] + " -- " + rdr[2]); } rdr.Close(); conn.Close(); } catch (Exception ex) { Console.WriteLine(ex.ToString()); } Console.WriteLine("Done."); } } } Further information on `LOAD DATA INFILE' can be found in *Note load-data::. Further information on `MySqlBulkLoader' can be found in the reference documentation that was included with your connector.  File: manual.info, Node: connector-net-connection-options, Next: connector-net-ref, Prev: connector-net-programming, Up: connector-net 21.2.6 Connector/NET Connection String Options Reference -------------------------------------------------------- Name Default Description `Allow Batch' true When true, multiple SQL statements can be sent with one command execution. -Note- Starting with MySQL 4.1.1, batch statements should be separated by the server-defined separator character. Commands sent to earlier versions of MySQL should be separated with ';'. `Allow User Variables' false Setting this to `true' indicates that the provider expects user variables in the SQL. This option was added in Connector/NET version 5.2.2. `Allow Zero Datetime' false If set to `True', `MySqlDataReader.GetValue()' will return a `MySqlDateTime' object for date or datetime columns that have illegal values, such as zero datetime values, and a `System.DateTime' object for legal values. If set to `False' (the default setting) it will cause a `System.DateTime' object to be returned for all legal values and an exception to be thrown for illegal values, such as zero datetime values. `AutoEnlist' true If `AutoEnlist' is set to `true', which is the default, a connection opened using `TransactionScope' participates in this scope, it commits when the scope commits and rolls back if `TransactionScope' does not commit. However, this feature is considered security sensitive and therefore cannot be used in a medium trust environment. `BlobAsUTF8ExcludePattern'null `BlobAsUTF8IncludePattern'null `CertificateFile' null This option specifies the path to a certificate file in PFX format. For an example of usage see *Note connector-net-tutorials-ssl::. Was introduced with 6.2.1. `CertificatePassword' null This option enables you to specify a password which is used in conjunction with a certificate specified using the option `CertificateFile'. For an example of usage see *Note connector-net-tutorials-ssl::. Was introduced with 6.2.1. `Certificate Store null This option enables you to access a Location' certificate held in a personal store, rather than use a certificate file and password combination. For an example of usage see *Note connector-net-tutorials-ssl::. Was introduced with 6.2.1. `Certificate Thumbprint' null This option enables you to specify a certificate thumbprint to ensure correct identifcation of a certificate contained within a personal store. For an example of usage see *Note connector-net-tutorials-ssl::. Was introduced with 6.2.1. `CharSet', `Character Specifies the character set that should Set' be used to encode all queries sent to the server. Resultsets are still returned in the character set of the data returned. `Connect Timeout', 15 The length of time (in seconds) to wait `Connection Timeout' for a connection to the server before terminating the attempt and generating an error. `Connection Reset' false If true, the connection state will be reset when it is retrieved from the pool. If set to false this avoids making an additional server round trip when obtaining a connection, but the connection state is not reset. `Convert Zero Datetime' false True to have `MySqlDataReader.GetValue()' and `MySqlDataReader.GetDateTime()' return DateTime.MinValue for date or datetime columns that have illegal values. `Default Command Timeout' 30 Sets the default value of the command timeout to be used. This does not supercede the individual command timeout property on an individual command object. If you set the command timeout property, that will be used. This option was added in Connector/NET 5.1.4 `Encrypt', `UseSSL' false For Connector/NET 5.0.3 and later, when `true', SSL encryption is used for all data sent between the client and server if the server has a certificate installed. Recognized values are `true', `false', `yes', and `no'. In versions before 5.0.3, this option had no effect. From version 6.2.1 this option is deprecated and is replaced by `SSL Mode'. However, the option is still supported if used. If this option is set to true it is equivalent to `SSL Mode = Preferred'. `FunctionsReturnString' false This will cause the connector to return binary/varbinary values as strings, if they do not have a tablename in the metadata. `Host', `Server', `Data localhostThe name or network address of the Source', `DataSource', instance of MySQL to which to connect. `Address', `Addr', Multiple hosts can be specified `Network Address' separated by &. This can be useful where multiple MySQL servers are configured for replication and you are not concerned about the precise server you are connecting to. No attempt is made by the provider to synchronize writes to the database so care should be taken when using this option. In Unix environment with Mono, this can be a fully qualified path to MySQL socket file name. With this configuration, the Unix socket will be used instead of TCP/IP socket. Currently only a single socket name can be given so accessing MySQL in a replicated environment using Unix sockets is not currently supported. `Ignore Prepare' true When true, instructs the provider to ignore any calls to `MySqlCommand.Prepare()'. This option is provided to prevent issues with corruption of the statements when use with server side prepared statements. If you want to use server-side prepare statements, set this option to false. This option was added in Connector/NET 5.0.3 and Connector/NET 1.0.9. `Initial Catalog', mysql The name of the database to use `Database' initially `Interactive, false If set to true the client is InteractiveSession' interactive. An interactive client is one where the server variable `CLIENT_INTERACTIVE' is set. If an interactive client is set, the `wait_timeout' variable is set to the value of `interactive_timeout'. The client will then timeout after this period of inactivity. More details can be found in the server manual *Note server-system-variables::. `Logging' false When true, various pieces of information is output to any configured TraceListeners. See *Note connector-net-programming-tracing:: for further details. `Old Guids' false This option was introduced in Connector/NET 6.1.1. The backend representation of a GUID type was changed from `BINARY(16)' to `CHAR(36)'. This was done to allow developers to use the server function `UUID()' to populate a GUID table - `UUID()' generates a 36-character string. Developers of older applications can add 'Old Guids=true' to the connection string to use a GUID of data type `BINARY(16)'. `Old Syntax', `OldSyntax' false This option was deprecated in Connector/NET 5.2.2. All code should now be written using the '@' symbol as the parameter marker. `Password', `pwd' The password for the MySQL account being used. `Persist Security Info' false When set to `false' or `no' (strongly recommended), security-sensitive information, such as the password, is not returned as part of the connection if the connection is open or has ever been in an open state. Resetting the connection string resets all connection string values including the password. Recognized values are `true', `false', `yes', and `no'. `Pipe Name', `Pipe' mysql When set to the name of a named pipe, the `MySqlConnection' will attempt to connect to MySQL on that named pipe.This settings only applies to the Windows platform. `Port' 3306 The port MySQL is using to listen for connections. This value is ignored if Unix socket is used. `Procedure Cache Size' 25 Sets the size of the stored procedure cache. By default, Connector/NET will store the metadata (input/output data types) about the last 25 stored procedures used. To disable the stored procedure cache, set the value to zero (0). This option was added in Connector/NET 5.0.2 and Connector/NET 1.0.9. `Protocol' socket Specifies the type of connection to make to the server. Values can be: `socket' or `tcp' for a socket connection, `pipe' for a named pipe connection, `unix' for a Unix socket connection, `memory' to use MySQL shared memory. `Respect Binary Flags' true Setting this option to `false' means that Connector/NET will ignore a column's binary flags as set by the server. This option was added in Connector/NET version 5.1.3. `Shared Memory Name' MYSQL The name of the shared memory object to use for communication if the connection protocol is set to memory. `Sql Server Mode' false Allow SQL Server syntax. When set to `true' enables Connector/NET to support square brackets around symbols instead of backticks. This enables Visual Studio wizards that bracket symbols with [] to work with Connector/NET. This option incurs a performance hit, so should only be used if necessary. This option was added in version 6.3.1. `SSL Mode' None This option has the following values: * *None* - do not use SSL. * *Preferred* - use SSL if the server supports it, but allow connection in all cases. * *Required* - Always use SSL. Deny connection if server does not support SSL. * *VerifyCA* - Always use SSL. Validate the CA but tolerate name mismatch. * *VerifyFull* - Always use SSL. Fail if the host name is not correct. This option was introduced in MySQL Connector/NET 6.2.1. `TreatBlobsAsUTF8' false `Treat Tiny As Boolean' true Setting this value to `false' indicates that `TINYINT(1)' will be treated as an *Note `INT': numeric-types. See also *Note numeric-type-overview:: for a further explanation of the *Note `TINYINT': numeric-types. and *Note `BOOL': numeric-types. data types. `Use Affected Rows' false When `true' the connection will report changed rows instead of found rows. This option was added in Connector/NET version 5.2.6. `Use Procedure Bodies' true When set to `true', the default value, MySQL Connector/NET expects the body of the procedure to be viewable. This enables it to determine the parameter types and order. The option should be set to `false' when the user connecting to the database does not have the `SELECT' privileges for the `mysql.proc' (stored procedures) table, or cannot view `I_S.ROUTINES'. In this case, MySQL Connector/NET will not be able to determine the types and order of the parameters, and must be alerted to this fact by setting this option to `false'. When set to `false', MySQL Connector/NET will not rely on this information being available when the procedure is called. Because MySQL Connector/NET will not be able to determine this information, you should explicitly set the types of all the parameters before the call and the parameters should be added to the command in the same order as they appear in the procedure definition. This option was added in MySQL Connector/NET 5.0.4 and MySQL Connector/NET 1.0.10. `User Id', `Username', The MySQL login account being used. `Uid', `User name' `Use Compression' false Setting this option to `true' enables compression of packets exchanged between the client and the server. This exchange is defined by the MySQL client/server protocol. Compression is used if both client and server support ZLIB compression, and the client has requested compression using this option. A compressed packet header is: packet length (3 bytes), packet number (1 byte), and Uncompressed Packet Length (3 bytes). The Uncompressed Packet Length is the number of bytes in the original, uncompressed packet. If this is zero then the data in this packet has not been compressed. When the compression protocol is in use, either the client or the server may compress packets. However, compression will not occur if the compressed length is greater than the original length. Thus, some packets will contain compressed data while other packets will not. `Use Usage Advisor' false `Use Performance Monitor' false The following table lists the valid names for connection pooling values within the `ConnectionString'. For more information about connection pooling, see Connection Pooling for the MySQL Data Provider. Name Default Description `Cache Server false Specifies whether server variables Configuration', should be updated when a pooled `CacheServerConfiguration', connection is returned. Turning this on `CacheServerConfig' will yield faster opens but will also not catch any server changes made by other connections. `Connection Lifetime' 0 When a connection is returned to the pool, its creation time is compared with the current time, and the connection is destroyed if that time span (in seconds) exceeds the value specified by `Connection Lifetime'. This is useful in clustered configurations to force load balancing between a running server and a server just brought online. A value of zero (0) causes pooled connections to have the maximum connection timeout. `Max Pool Size' 100 The maximum number of connections allowed in the pool. `Min Pool Size' 0 The minimum number of connections allowed in the pool. `Pooling' true When `true', the `MySqlConnection' object is drawn from the appropriate pool, or if necessary, is created and added to the appropriate pool. Recognized values are `true', `false', `yes', and `no'.  File: manual.info, Node: connector-net-ref, Next: connect-net-support, Prev: connector-net-connection-options, Up: connector-net 21.2.7 Connector/NET API Reference ---------------------------------- * Menu: * connector-net-ref-mysqlclient:: `MySql.Data.MySqlClient' * connector-net-ref-types:: `MySql.Data.Types' This section of the manual contains a complete reference to the Connector/NET ADO.NET component, automatically generated from the embedded documentation.  File: manual.info, Node: connector-net-ref-mysqlclient, Next: connector-net-ref-types, Prev: connector-net-ref, Up: connector-net-ref 21.2.7.1 `MySql.Data.MySqlClient' ................................. * Menu: * connector-net-ref-mysqlclienthierarchy:: `MySql.Data.MySqlClientHierarchy' * connector-net-ref-mysqlclient-mysqlcommand:: `MySqlCommand' Class * connector-net-ref-mysqlclient-mysqlcommandbuilder:: `MySqlCommandBuilder' Class * connector-net-ref-mysqlclient-mysqlexception:: `MySqlException' Class * connector-net-ref-mysqlclient-mysqlhelper:: `MySqlHelper' Class * connector-net-ref-mysqlclient-mysqlerrorcode:: `MySqlErrorCode' Enumeration *Note Namespace hierarchy: connector-net-ref-mysqlclienthierarchy. *Classes* Class Description *Note MySqlCommand: connector-net-ref-mysqlclient-mysqlcommand. *Note MySqlCommandBuilder: connector-net-ref-mysqlclient-mysqlcommandbuilder. *Note MySqlConnection: connector-net-ref-mysqlclient-mysqlconnection. *Note MySqlDataAdapter: connector-net-ref-mysqlclient-mysqldataadapter. *Note MySqlDataReader: Provides a means of reading a connector-net-ref-mysqlclient-mysqldatareader.forward-only stream of rows from a MySQL database. This class cannot be inherited. *Note MySqlError: Collection of error codes that can connector-net-ref-mysqlclient-mysqlerror.be returned by the server *Note MySqlException: The exception that is thrown when connector-net-ref-mysqlclient-mysqlexception.MySQL returns an error. This class cannot be inherited. *Note MySqlHelper: Helper class that makes it easier connector-net-ref-mysqlclient-mysqlhelper.to work with the provider. *Note MySqlInfoMessageEventArgs: Provides data for the InfoMessage connector-net-ref-mysqlclient-mysqlinfomessageeventargs.event. This class cannot be inherited. *Note MySqlParameter: Represents a parameter to a *Note connector-net-ref-mysqlclient-mysqlparameter.MySqlCommand: connector-net-ref-mysqlclient-mysqlcommand , and optionally, its mapping to DataSetcolumns. This class cannot be inherited. *Note MySqlParameterCollection: Represents a collection of connector-net-ref-mysqlclient-mysqlparametercollection.parameters relevant to a *Note MySqlCommand: connector-net-ref-mysqlclient-mysqlcommand. as well as their respective mappings to columns in a DataSet. This class cannot be inherited. *Note MySqlRowUpdatedEventArgs: Provides data for the RowUpdated connector-net-ref-mysqlclient-mysqlrowupdatedeventargs.event. This class cannot be inherited. *Note MySqlRowUpdatingEventArgs: Provides data for the RowUpdating connector-net-ref-mysqlclient-mysqlrowupdatingeventargs.event. This class cannot be inherited. *Note MySqlTransaction: connector-net-ref-mysqlclient-mysqltransaction. *Delegates* Delegate Description *Note MySqlInfoMessageEventHandler: Represents the method that will connector-net-ref-mysqlclient-mysqlinfomessageeventhandler.handle the *Note InfoMessage: connector-net-ref-mysqlclient-mysqlconnection-infomessage. event of a *Note MySqlConnection: connector-net-ref-mysqlclient-mysqlconnection. *Note MySqlRowUpdatedEventHandler: Represents the method that will connector-net-ref-mysqlclient-mysqlrowupdatedeventhandler.handle the RowUpdatedevent of a *Note MySqlDataAdapter: connector-net-ref-mysqlclient-mysqldataadapter . *Note MySqlRowUpdatingEventHandler: Represents the method that will connector-net-ref-mysqlclient-mysqlrowupdatingeventhandler.handle the RowUpdatingevent of a *Note MySqlDataAdapter: connector-net-ref-mysqlclient-mysqldataadapter . *Enumerations* Enumeration Description *Note MySqlDbType: Specifies MySQL specific data type connector-net-ref-mysqlclient-mysqldbtype.of a field, property, for use in a *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter . *Note MySqlErrorCode: connector-net-ref-mysqlclient-mysqlerrorcode.  File: manual.info, Node: connector-net-ref-mysqlclienthierarchy, Next: connector-net-ref-mysqlclient-mysqlcommand, Prev: connector-net-ref-mysqlclient, Up: connector-net-ref-mysqlclient 21.2.7.2 `MySql.Data.MySqlClientHierarchy' .......................................... *See Also* *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlcommand, Next: connector-net-ref-mysqlclient-mysqlcommandbuilder, Prev: connector-net-ref-mysqlclienthierarchy, Up: connector-net-ref-mysqlclient 21.2.7.3 `MySqlCommand' Class ............................. * Menu: * connector-net-ref-mysqlclient-mysqlcommandmembers:: `MySqlCommand' Members For a list of all members of this type, see *Note MySqlCommand Members: connector-net-ref-mysqlclient-mysqlcommandmembers . *Syntax: Visual Basic* NotInheritable Public Class MySqlCommand_ Inherits Component_ Implements IDbCommand, ICloneable *Syntax: C#* public sealed class MySqlCommand : Component, IDbCommand, ICloneable *Thread Safety* Public static (Shared in Visual Basic) members of this type are safe for multithreaded operations. Instance members are not guaranteed to be thread-safe. *Requirements* Namespace: *Note MySql.Data.MySqlClient: connector-net-ref-mysqlclient. Assembly: MySql.Data (in MySql.Data.dll) *See Also* *Note MySqlCommand Members: connector-net-ref-mysqlclient-mysqlcommandmembers, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlcommandmembers, Prev: connector-net-ref-mysqlclient-mysqlcommand, Up: connector-net-ref-mysqlclient-mysqlcommand 21.2.7.4 `MySqlCommand' Members ............................... * Menu: * connector-net-ref-mysqlclient-mysqlcommandconstructor:: `MySqlCommand' Constructor * connector-net-ref-mysqlclient-mysqlcommand-commandtext:: CommandText Property * connector-net-ref-mysqlclient-mysqlcommand-commandtimeout:: CommandTimeout Property * connector-net-ref-mysqlclient-mysqlcommand-commandtype:: CommandType Property * connector-net-ref-mysqlclient-mysqlcommand-connection:: Connection Property * connector-net-ref-mysqlclient-mysqlcommand-isprepared:: IsPrepared Property * connector-net-ref-mysqlclient-mysqlcommand-parameters:: Parameters Property * connector-net-ref-mysqlclient-mysqlcommand-transaction:: Transaction Property * connector-net-ref-mysqlclient-mysqlcommand-updatedrowsource:: UpdatedRowSource Property * connector-net-ref-mysqlclient-mysqlcommand-cancel:: `MySqlCommand.Cancel' Method * connector-net-ref-mysqlclient-mysqlcommand-createparameter:: `MySqlCommand.CreateParameter' Method * connector-net-ref-mysqlclient-mysqlcommand-executenonquery:: `MySqlCommand.ExecuteNonQuery' Method * connector-net-ref-mysqlclient-mysqlcommand-executereader-overloads:: ExecuteReader Method * connector-net-ref-mysqlclient-mysqlcommand-executescalar:: `MySqlCommand.ExecuteScalar' Method * connector-net-ref-mysqlclient-mysqlcommand-prepare:: `MySqlCommand.Prepare' Method *Note MySqlCommand overview: connector-net-ref-mysqlclient-mysqlcommand. *Public Instance Constructors* *Note MySqlCommand: Overloaded. Initializes a new connector-net-ref-mysqlclient-mysqlcommandconstructor.instance of the MySqlCommand class. *Public Instance Properties* *Note CommandText: connector-net-ref-mysqlclient-mysqlcommand-commandtext. *Note CommandTimeout: connector-net-ref-mysqlclient-mysqlcommand-commandtimeout. *Note CommandType: connector-net-ref-mysqlclient-mysqlcommand-commandtype. *Note Connection: connector-net-ref-mysqlclient-mysqlcommand-connection. Container(inherited from Component) Gets the IContainerthat contains the Component. *Note IsPrepared: connector-net-ref-mysqlclient-mysqlcommand-isprepared. *Note Parameters: connector-net-ref-mysqlclient-mysqlcommand-parameters. Site(inherited from Component) Gets or sets the ISiteof the Component. *Note Transaction: connector-net-ref-mysqlclient-mysqlcommand-transaction. *Note UpdatedRowSource: connector-net-ref-mysqlclient-mysqlcommand-updatedrowsource. *Public Instance Methods* *Note Cancel: Attempts to cancel the execution of connector-net-ref-mysqlclient-mysqlcommand-cancel.a MySqlCommand. This operation is not supported. CreateObjRef(inherited from Creates an object that contains all MarshalByRefObject) the relevant information required to generate a proxy used to communicate with a remote object. *Note CreateParameter: Creates a new instance of a *Note connector-net-ref-mysqlclient-mysqlcommand-createparameter.MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. object. Dispose(inherited from Component) Releases all resources used by the Component. Equals(inherited from Object) Determines whether the specified Objectis equal to the current Object. *Note ExecuteNonQuery: connector-net-ref-mysqlclient-mysqlcommand-executenonquery. *Note ExecuteReader: Overloaded. connector-net-ref-mysqlclient-mysqlcommand-executereader-overloads. *Note ExecuteScalar: connector-net-ref-mysqlclient-mysqlcommand-executescalar. GetHashCode(inherited from Object) Serves as a hash function for a particular type. GetHashCodeis suitable for use in hashing algorithms and data structures like a hash table. GetLifetimeService(inherited from Retrieves the current lifetime MarshalByRefObject) service object that controls the lifetime policy for this instance. GetType(inherited from Object) Gets the Typeof the current instance. InitializeLifetimeService(inherited Obtains a lifetime service object from MarshalByRefObject) to control the lifetime policy for this instance. *Note Prepare: connector-net-ref-mysqlclient-mysqlcommand-prepare. ToString(inherited from Component) Returns a Stringcontaining the name of the Component, if any. This method should not be overridden. *Public Instance Events* Disposed(inherited from Component) Adds an event handler to listen to the Disposedevent on the component. *See Also* *Note MySqlCommand Class: connector-net-ref-mysqlclient-mysqlcommand, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlcommandconstructor, Next: connector-net-ref-mysqlclient-mysqlcommand-commandtext, Prev: connector-net-ref-mysqlclient-mysqlcommandmembers, Up: connector-net-ref-mysqlclient-mysqlcommandmembers 21.2.7.5 `MySqlCommand' Constructor ................................... * Menu: * connector-net-ref-mysqlclient-mysqlcommandconstructor1:: `MySqlCommand' Constructor () * connector-net-ref-mysqlclient-mysqlcommandconstructor2:: `MySqlCommand' Constructor (String) * connector-net-ref-mysqlclient-mysqlcommandconstructor3:: `MySqlCommand' Constructor * connector-net-ref-mysqlclient-mysqlcommandconstructor4:: `MySqlCommand' Constructor Initializes a new instance of the *Note MySqlCommand: connector-net-ref-mysqlclient-mysqlcommand. class. *Overload List* Initializes a new instance of the *Note MySqlCommand: connector-net-ref-mysqlclient-mysqlcommand. class. * *Note public MySqlCommand();: connector-net-ref-mysqlclient-mysqlcommandconstructor1. * *Note public MySqlCommand(string);: connector-net-ref-mysqlclient-mysqlcommandconstructor2. * *Note public MySqlCommand(string: (MySqlConnection);)connector-net-ref-mysqlclient-mysqlcommandconstructor3. * *Note public MySqlCommand(string: (MySqlConnection)connector-net-ref-mysqlclient-mysqlcommandconstructor4. *See Also* *Note MySqlCommand Class: connector-net-ref-mysqlclient-mysqlcommand, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlcommandconstructor1, Next: connector-net-ref-mysqlclient-mysqlcommandconstructor2, Prev: connector-net-ref-mysqlclient-mysqlcommandconstructor, Up: connector-net-ref-mysqlclient-mysqlcommandconstructor 21.2.7.6 `MySqlCommand' Constructor () ...................................... Initializes a new instance of the *Note MySqlCommand: connector-net-ref-mysqlclient-mysqlcommand. class. *Syntax: Visual Basic* Overloads Public Sub New() *Syntax: C#* public MySqlCommand(); *See Also* *Note MySqlCommand Class: connector-net-ref-mysqlclient-mysqlcommand, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note MySqlCommand Constructor Overload List: connector-net-ref-mysqlclient-mysqlcommandconstructor.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlcommandconstructor2, Next: connector-net-ref-mysqlclient-mysqlcommandconstructor3, Prev: connector-net-ref-mysqlclient-mysqlcommandconstructor1, Up: connector-net-ref-mysqlclient-mysqlcommandconstructor 21.2.7.7 `MySqlCommand' Constructor (String) ............................................ *Syntax: Visual Basic* Overloads Public Sub New( _ ByVal cmdText As String _ ) *Syntax: C#* public MySqlCommand( stringcmdText ); *See Also* *Note MySqlCommand Class: connector-net-ref-mysqlclient-mysqlcommand, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note MySqlCommand Constructor Overload List: connector-net-ref-mysqlclient-mysqlcommandconstructor.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlcommandconstructor3, Next: connector-net-ref-mysqlclient-mysqlcommandconstructor4, Prev: connector-net-ref-mysqlclient-mysqlcommandconstructor2, Up: connector-net-ref-mysqlclient-mysqlcommandconstructor 21.2.7.8 `MySqlCommand' Constructor ................................... * Menu: * connector-net-ref-mysqlclient-mysqlconnection:: `MySqlConnection' Class *Syntax: Visual Basic* Overloads Public Sub New( _ ByVal cmdText As String, _ ByVal connection As MySqlConnection _ ) *Syntax: C#* public MySqlCommand( stringcmdText, MySqlConnectionconnection ); *See Also* *Note MySqlCommand Class: connector-net-ref-mysqlclient-mysqlcommand, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note MySqlCommand Constructor Overload List: connector-net-ref-mysqlclient-mysqlcommandconstructor.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlconnection, Prev: connector-net-ref-mysqlclient-mysqlcommandconstructor3, Up: connector-net-ref-mysqlclient-mysqlcommandconstructor3 21.2.7.9 `MySqlConnection' Class ................................ * Menu: * connector-net-ref-mysqlclient-mysqlconnectionmembers:: `MySqlConnection' Members For a list of all members of this type, see *Note MySqlConnection Members: connector-net-ref-mysqlclient-mysqlconnectionmembers . *Syntax: Visual Basic* NotInheritable Public Class MySqlConnection_ Inherits Component_ Implements IDbConnection, ICloneable *Syntax: C#* public sealed class MySqlConnection : Component, IDbConnection, ICloneable *Thread Safety* Public static (Shared in Visual Basic) members of this type are safe for multithreaded operations. Instance members are not guaranteed to be thread-safe. *Requirements* Namespace: *Note MySql.Data.MySqlClient: connector-net-ref-mysqlclient. Assembly: MySql.Data (in MySql.Data.dll) *See Also* *Note MySqlConnection Members: connector-net-ref-mysqlclient-mysqlconnectionmembers, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlconnectionmembers, Prev: connector-net-ref-mysqlclient-mysqlconnection, Up: connector-net-ref-mysqlclient-mysqlconnection 21.2.7.10 `MySqlConnection' Members ................................... * Menu: * connector-net-ref-mysqlclient-mysqlconnectionconstructor:: `MySqlConnection' Constructor * connector-net-ref-mysqlclient-mysqlconnection-connectionstring:: ConnectionString Property * connector-net-ref-mysqlclient-mysqlconnection-connectiontimeout:: ConnectionTimeout Property * connector-net-ref-mysqlclient-mysqlconnection-database:: Database Property * connector-net-ref-mysqlclient-mysqlconnection-datasource:: DataSource Property * connector-net-ref-mysqlclient-mysqlconnection-serverthread:: ServerThread Property * connector-net-ref-mysqlclient-mysqlconnection-serverversion:: ServerVersion Property * connector-net-ref-mysqlclient-mysqlconnection-state:: State Property * connector-net-ref-mysqlclient-mysqlconnection-usecompression:: UseCompression Property * connector-net-ref-mysqlclient-mysqlconnection-begintransaction-overloads:: BeginTransaction Method * connector-net-ref-mysqlclient-mysqlconnection-changedatabase:: `MySqlConnection.ChangeDatabase' Method * connector-net-ref-mysqlclient-mysqlconnection-close:: `MySqlConnection.Close' Method * connector-net-ref-mysqlclient-mysqlconnection-createcommand:: `MySqlConnection.CreateCommand' Method * connector-net-ref-mysqlclient-mysqlconnection-open:: `MySqlConnection.Open' Method * connector-net-ref-mysqlclient-mysqlconnection-ping:: `MySqlConnection.Ping' Method * connector-net-ref-mysqlclient-mysqlconnection-infomessage:: `MySqlConnection.InfoMessage' Event * connector-net-ref-mysqlclient-mysqlconnection-statechange:: `MySqlConnection.StateChange' Event *Note MySqlConnection overview: connector-net-ref-mysqlclient-mysqlconnection. *Public Instance Constructors* *Note MySqlConnection: Overloaded. Initializes a new connector-net-ref-mysqlclient-mysqlconnectionconstructor.instance of the MySqlConnection class. *Public Instance Properties* *Note ConnectionString: connector-net-ref-mysqlclient-mysqlconnection-connectionstring. *Note ConnectionTimeout: connector-net-ref-mysqlclient-mysqlconnection-connectiontimeout. Container(inherited from Component) Gets the IContainerthat contains the Component. *Note Database: connector-net-ref-mysqlclient-mysqlconnection-database. *Note DataSource: Gets the name of the MySQL server connector-net-ref-mysqlclient-mysqlconnection-datasource.to which to connect. *Note ServerThread: Returns the id of the server thread connector-net-ref-mysqlclient-mysqlconnection-serverthread.this connection is executing on *Note ServerVersion: connector-net-ref-mysqlclient-mysqlconnection-serverversion. Site(inherited from Component) Gets or sets the ISiteof the Component. *Note State: connector-net-ref-mysqlclient-mysqlconnection-state. *Note UseCompression: Indicates if this connection should connector-net-ref-mysqlclient-mysqlconnection-usecompression.use compression when communicating with the server. *Public Instance Methods* *Note BeginTransaction: Overloaded. connector-net-ref-mysqlclient-mysqlconnection-begintransaction-overloads. *Note ChangeDatabase: connector-net-ref-mysqlclient-mysqlconnection-changedatabase. *Note Close: connector-net-ref-mysqlclient-mysqlconnection-close. *Note CreateCommand: connector-net-ref-mysqlclient-mysqlconnection-createcommand. CreateObjRef(inherited from Creates an object that contains all MarshalByRefObject) the relevant information required to generate a proxy used to communicate with a remote object. Dispose(inherited from Component) Releases all resources used by the Component. Equals(inherited from Object) Determines whether the specified Objectis equal to the current Object. GetHashCode(inherited from Object) Serves as a hash function for a particular type. GetHashCodeis suitable for use in hashing algorithms and data structures like a hash table. GetLifetimeService(inherited from Retrieves the current lifetime MarshalByRefObject) service object that controls the lifetime policy for this instance. GetType(inherited from Object) Gets the Typeof the current instance. InitializeLifetimeService(inherited Obtains a lifetime service object from MarshalByRefObject) to control the lifetime policy for this instance. *Note Open: connector-net-ref-mysqlclient-mysqlconnection-open. *Note Ping: Ping connector-net-ref-mysqlclient-mysqlconnection-ping. ToString(inherited from Component) Returns a Stringcontaining the name of the Component, if any. This method should not be overridden. *Public Instance Events* Disposed(inherited from Component) Adds an event handler to listen to the Disposedevent on the component. *Note InfoMessage: connector-net-ref-mysqlclient-mysqlconnection-infomessage. *Note StateChange: connector-net-ref-mysqlclient-mysqlconnection-statechange. *See Also* *Note MySqlConnection Class: connector-net-ref-mysqlclient-mysqlconnection, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlconnectionconstructor, Next: connector-net-ref-mysqlclient-mysqlconnection-connectionstring, Prev: connector-net-ref-mysqlclient-mysqlconnectionmembers, Up: connector-net-ref-mysqlclient-mysqlconnectionmembers 21.2.7.11 `MySqlConnection' Constructor ....................................... * Menu: * connector-net-ref-mysqlclient-mysqlconnectionconstructor1:: `MySqlConnection' Constructor * connector-net-ref-mysqlclient-mysqlconnectionconstructor2:: `MySqlConnection' Constructor Initializes a new instance of the *Note MySqlConnection: connector-net-ref-mysqlclient-mysqlconnection. class. *Overload List* Initializes a new instance of the *Note MySqlConnection: connector-net-ref-mysqlclient-mysqlconnection. class. * *Note public MySqlConnection();: connector-net-ref-mysqlclient-mysqlconnectionconstructor1. * *Note public MySqlConnection(string);: connector-net-ref-mysqlclient-mysqlconnectionconstructor2. *See Also* *Note MySqlConnection Class: connector-net-ref-mysqlclient-mysqlconnection, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlconnectionconstructor1, Next: connector-net-ref-mysqlclient-mysqlconnectionconstructor2, Prev: connector-net-ref-mysqlclient-mysqlconnectionconstructor, Up: connector-net-ref-mysqlclient-mysqlconnectionconstructor 21.2.7.12 `MySqlConnection' Constructor ....................................... Initializes a new instance of the *Note MySqlConnection: connector-net-ref-mysqlclient-mysqlconnection. class. *Syntax: Visual Basic* Overloads Public Sub New() *Syntax: C#* public MySqlConnection(); *See Also* *Note MySqlConnection Class: connector-net-ref-mysqlclient-mysqlconnection, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note MySqlConnection Constructor Overload List: connector-net-ref-mysqlclient-mysqlconnectionconstructor.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlconnectionconstructor2, Prev: connector-net-ref-mysqlclient-mysqlconnectionconstructor1, Up: connector-net-ref-mysqlclient-mysqlconnectionconstructor 21.2.7.13 `MySqlConnection' Constructor ....................................... *Syntax: Visual Basic* Overloads Public Sub New( _ ByVal connectionString As String _ ) *Syntax: C#* public MySqlConnection( stringconnectionString ); *See Also* *Note MySqlConnection Class: connector-net-ref-mysqlclient-mysqlconnection, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note MySqlConnection Constructor Overload List: connector-net-ref-mysqlclient-mysqlconnectionconstructor.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlconnection-connectionstring, Next: connector-net-ref-mysqlclient-mysqlconnection-connectiontimeout, Prev: connector-net-ref-mysqlclient-mysqlconnectionconstructor, Up: connector-net-ref-mysqlclient-mysqlconnectionmembers 21.2.7.14 ConnectionString Property ................................... *Syntax: Visual Basic* NotOverridable Public Property ConnectionString As String _ _ Implements IDbConnection.ConnectionString *Syntax: C#* public string ConnectionString {get; set;} *Implements* IDbConnection.ConnectionString *See Also* *Note MySqlConnection Class: connector-net-ref-mysqlclient-mysqlconnection, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlconnection-connectiontimeout, Next: connector-net-ref-mysqlclient-mysqlconnection-database, Prev: connector-net-ref-mysqlclient-mysqlconnection-connectionstring, Up: connector-net-ref-mysqlclient-mysqlconnectionmembers 21.2.7.15 ConnectionTimeout Property .................................... *Syntax: Visual Basic* NotOverridable Public ReadOnly Property ConnectionTimeout As Integer _ _ Implements IDbConnection.ConnectionTimeout *Syntax: C#* public int ConnectionTimeout {get;} *Implements* IDbConnection.ConnectionTimeout *See Also* *Note MySqlConnection Class: connector-net-ref-mysqlclient-mysqlconnection, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlconnection-database, Next: connector-net-ref-mysqlclient-mysqlconnection-datasource, Prev: connector-net-ref-mysqlclient-mysqlconnection-connectiontimeout, Up: connector-net-ref-mysqlclient-mysqlconnectionmembers 21.2.7.16 Database Property ........................... *Syntax: Visual Basic* NotOverridable Public ReadOnly Property Database As String _ _ Implements IDbConnection.Database *Syntax: C#* public string Database {get;} *Implements* IDbConnection.Database *See Also* *Note MySqlConnection Class: connector-net-ref-mysqlclient-mysqlconnection, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlconnection-datasource, Next: connector-net-ref-mysqlclient-mysqlconnection-serverthread, Prev: connector-net-ref-mysqlclient-mysqlconnection-database, Up: connector-net-ref-mysqlclient-mysqlconnectionmembers 21.2.7.17 DataSource Property ............................. Gets the name of the MySQL server to which to connect. *Syntax: Visual Basic* Public ReadOnly Property DataSource As String *Syntax: C#* public string DataSource {get;} *See Also* *Note MySqlConnection Class: connector-net-ref-mysqlclient-mysqlconnection, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlconnection-serverthread, Next: connector-net-ref-mysqlclient-mysqlconnection-serverversion, Prev: connector-net-ref-mysqlclient-mysqlconnection-datasource, Up: connector-net-ref-mysqlclient-mysqlconnectionmembers 21.2.7.18 ServerThread Property ............................... Returns the id of the server thread this connection is executing on *Syntax: Visual Basic* Public ReadOnly Property ServerThread As Integer *Syntax: C#* public int ServerThread {get;} *See Also* *Note MySqlConnection Class: connector-net-ref-mysqlclient-mysqlconnection, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlconnection-serverversion, Next: connector-net-ref-mysqlclient-mysqlconnection-state, Prev: connector-net-ref-mysqlclient-mysqlconnection-serverthread, Up: connector-net-ref-mysqlclient-mysqlconnectionmembers 21.2.7.19 ServerVersion Property ................................ *Syntax: Visual Basic* Public ReadOnly Property ServerVersion As String *Syntax: C#* public string ServerVersion {get;} *See Also* *Note MySqlConnection Class: connector-net-ref-mysqlclient-mysqlconnection, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlconnection-state, Next: connector-net-ref-mysqlclient-mysqlconnection-usecompression, Prev: connector-net-ref-mysqlclient-mysqlconnection-serverversion, Up: connector-net-ref-mysqlclient-mysqlconnectionmembers 21.2.7.20 State Property ........................ *Syntax: Visual Basic* NotOverridable Public ReadOnly Property State As ConnectionState _ _ Implements IDbConnection.State *Syntax: C#* public System.Data.ConnectionState State {get;} *Implements* IDbConnection.State *See Also* *Note MySqlConnection Class: connector-net-ref-mysqlclient-mysqlconnection, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlconnection-usecompression, Next: connector-net-ref-mysqlclient-mysqlconnection-begintransaction-overloads, Prev: connector-net-ref-mysqlclient-mysqlconnection-state, Up: connector-net-ref-mysqlclient-mysqlconnectionmembers 21.2.7.21 UseCompression Property ................................. Indicates if this connection should use compression when communicating with the server. *Syntax: Visual Basic* Public ReadOnly Property UseCompression As Boolean *Syntax: C#* public bool UseCompression {get;} *See Also* *Note MySqlConnection Class: connector-net-ref-mysqlclient-mysqlconnection, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlconnection-begintransaction-overloads, Next: connector-net-ref-mysqlclient-mysqlconnection-changedatabase, Prev: connector-net-ref-mysqlclient-mysqlconnection-usecompression, Up: connector-net-ref-mysqlclient-mysqlconnectionmembers 21.2.7.22 BeginTransaction Method ................................. * Menu: * connector-net-ref-mysqlclient-mysqlconnection-begintransaction-overload-1:: `MySqlConnection.BeginTransaction' Method * connector-net-ref-mysqlclient-mysqlconnection-begintransaction-overload-2:: `MySqlConnection.BeginTransaction' Method *Overload List* * *Note public MySqlTransaction BeginTransaction();: connector-net-ref-mysqlclient-mysqlconnection-begintransaction-overload-1. * *Note public MySqlTransaction BeginTransaction(IsolationLevel);: connector-net-ref-mysqlclient-mysqlconnection-begintransaction-overload-2. *See Also* *Note MySqlConnection Class: connector-net-ref-mysqlclient-mysqlconnection, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlconnection-begintransaction-overload-1, Next: connector-net-ref-mysqlclient-mysqlconnection-begintransaction-overload-2, Prev: connector-net-ref-mysqlclient-mysqlconnection-begintransaction-overloads, Up: connector-net-ref-mysqlclient-mysqlconnection-begintransaction-overloads 21.2.7.23 `MySqlConnection.BeginTransaction' Method ................................................... * Menu: * connector-net-ref-mysqlclient-mysqltransaction:: `MySqlTransaction' Class *Syntax: Visual Basic* Overloads Public Function BeginTransaction() As MySqlTransaction *Syntax: C#* public MySqlTransaction BeginTransaction(); *See Also* *Note MySqlConnection Class: connector-net-ref-mysqlclient-mysqlconnection, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note MySqlConnection.BeginTransaction Overload List: connector-net-ref-mysqlclient-mysqlconnection-begintransaction-overloads.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqltransaction, Prev: connector-net-ref-mysqlclient-mysqlconnection-begintransaction-overload-1, Up: connector-net-ref-mysqlclient-mysqlconnection-begintransaction-overload-1 21.2.7.24 `MySqlTransaction' Class .................................. * Menu: * connector-net-ref-mysqlclient-mysqltransactionmembers:: `MySqlTransaction' Members For a list of all members of this type, see *Note MySqlTransaction Members: connector-net-ref-mysqlclient-mysqltransactionmembers . *Syntax: Visual Basic* NotInheritable Public Class MySqlTransaction_ Implements IDbTransaction, IDisposable *Syntax: C#* public sealed class MySqlTransaction : IDbTransaction, IDisposable *Thread Safety* Public static (Sharedin Visual Basic) members of this type are safe for multithreaded operations. Instance members are notguaranteed to be thread-safe. *Requirements* Namespace: *Note MySql.Data.MySqlClient: connector-net-ref-mysqlclient. Assembly: MySql.Data (in MySql.Data.dll) *See Also* *Note MySqlTransaction Members: connector-net-ref-mysqlclient-mysqltransactionmembers, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqltransactionmembers, Prev: connector-net-ref-mysqlclient-mysqltransaction, Up: connector-net-ref-mysqlclient-mysqltransaction 21.2.7.25 `MySqlTransaction' Members .................................... * Menu: * connector-net-ref-mysqlclient-mysqltransaction-connection:: Connection Property * connector-net-ref-mysqlclient-mysqltransaction-isolationlevel:: IsolationLevel Property * connector-net-ref-mysqlclient-mysqltransaction-commit:: `MySqlTransaction.Commit' Method * connector-net-ref-mysqlclient-mysqltransaction-rollback:: `MySqlTransaction.Rollback' Method *Note MySqlTransaction overview: connector-net-ref-mysqlclient-mysqltransaction. *Public Instance Properties* *Note Connection: Gets the *Note MySqlConnection: connector-net-ref-mysqlclient-mysqltransaction-connection.connector-net-ref-mysqlclient-mysqlconnection. object associated with the transaction, or a null reference (Nothing in Visual Basic) if the transaction is no longer valid. *Note IsolationLevel: Specifies the IsolationLevelfor connector-net-ref-mysqlclient-mysqltransaction-isolationlevel.this transaction. *Public Instance Methods* *Note Commit: connector-net-ref-mysqlclient-mysqltransaction-commit. Equals(inherited from Object) Determines whether the specified Objectis equal to the current Object. GetHashCode(inherited from Object) Serves as a hash function for a particular type. GetHashCodeis suitable for use in hashing algorithms and data structures like a hash table. GetType(inherited from Object) Gets the Typeof the current instance. *Note Rollback: connector-net-ref-mysqlclient-mysqltransaction-rollback. ToString(inherited from Object) Returns a Stringthat represents the current Object. *See Also* *Note MySqlTransaction Class: connector-net-ref-mysqlclient-mysqltransaction, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqltransaction-connection, Next: connector-net-ref-mysqlclient-mysqltransaction-isolationlevel, Prev: connector-net-ref-mysqlclient-mysqltransactionmembers, Up: connector-net-ref-mysqlclient-mysqltransactionmembers 21.2.7.26 Connection Property ............................. Gets the *Note MySqlConnection: connector-net-ref-mysqlclient-mysqlconnection. object associated with the transaction, or a null reference (Nothing in Visual Basic) if the transaction is no longer valid. *Syntax: Visual Basic* Public ReadOnly Property Connection As MySqlConnection *Syntax: C#* public MySqlConnection Connection {get;} *Property Value* The *Note MySqlConnection: connector-net-ref-mysqlclient-mysqlconnection. object associated with this transaction. *Remarks* A single application may have multiple database connections, each with zero or more transactions. This property enables you to determine the connection object associated with a particular transaction created by *Note BeginTransaction: connector-net-ref-mysqlclient-mysqlconnection-begintransaction-overload-1 . *See Also* *Note MySqlTransaction Class: connector-net-ref-mysqlclient-mysqltransaction, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqltransaction-isolationlevel, Next: connector-net-ref-mysqlclient-mysqltransaction-commit, Prev: connector-net-ref-mysqlclient-mysqltransaction-connection, Up: connector-net-ref-mysqlclient-mysqltransactionmembers 21.2.7.27 IsolationLevel Property ................................. Specifies the IsolationLevelfor this transaction. *Syntax: Visual Basic* NotOverridable Public ReadOnly Property IsolationLevel As IsolationLevel _ _ Implements IDbTransaction.IsolationLevel *Syntax: C#* public System.Data.IsolationLevel IsolationLevel {get;} *Property Value* The IsolationLevel for this transaction. The default is ReadCommitted. *Implements* IDbTransaction.IsolationLevel *Remarks* Parallel transactions are not supported. Therefore, the IsolationLevel applies to the entire transaction. *See Also* *Note MySqlTransaction Class: connector-net-ref-mysqlclient-mysqltransaction, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqltransaction-commit, Next: connector-net-ref-mysqlclient-mysqltransaction-rollback, Prev: connector-net-ref-mysqlclient-mysqltransaction-isolationlevel, Up: connector-net-ref-mysqlclient-mysqltransactionmembers 21.2.7.28 `MySqlTransaction.Commit' Method .......................................... *Syntax: Visual Basic* NotOverridable Public Sub Commit() _ _ Implements IDbTransaction.Commit *Syntax: C#* public void Commit(); *Implements* IDbTransaction.Commit *See Also* *Note MySqlTransaction Class: connector-net-ref-mysqlclient-mysqltransaction, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqltransaction-rollback, Prev: connector-net-ref-mysqlclient-mysqltransaction-commit, Up: connector-net-ref-mysqlclient-mysqltransactionmembers 21.2.7.29 `MySqlTransaction.Rollback' Method ............................................ *Syntax: Visual Basic* NotOverridable Public Sub Rollback() _ _ Implements IDbTransaction.Rollback *Syntax: C#* public void Rollback(); *Implements* IDbTransaction.Rollback *See Also* *Note MySqlTransaction Class: connector-net-ref-mysqlclient-mysqltransaction, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlconnection-begintransaction-overload-2, Prev: connector-net-ref-mysqlclient-mysqlconnection-begintransaction-overload-1, Up: connector-net-ref-mysqlclient-mysqlconnection-begintransaction-overloads 21.2.7.30 `MySqlConnection.BeginTransaction' Method ................................................... *Syntax: Visual Basic* Overloads Public Function BeginTransaction( _ ByVal iso As IsolationLevel _ ) As MySqlTransaction *Syntax: C#* public MySqlTransaction BeginTransaction( IsolationLeveliso ); *See Also* *Note MySqlConnection Class: connector-net-ref-mysqlclient-mysqlconnection, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note MySqlConnection.BeginTransaction Overload List: connector-net-ref-mysqlclient-mysqlconnection-begintransaction-overloads.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlconnection-changedatabase, Next: connector-net-ref-mysqlclient-mysqlconnection-close, Prev: connector-net-ref-mysqlclient-mysqlconnection-begintransaction-overloads, Up: connector-net-ref-mysqlclient-mysqlconnectionmembers 21.2.7.31 `MySqlConnection.ChangeDatabase' Method ................................................. *Syntax: Visual Basic* NotOverridable Public Sub ChangeDatabase( _ ByVal databaseName As String _ ) _ _ Implements IDbConnection.ChangeDatabase *Syntax: C#* public void ChangeDatabase( stringdatabaseName ); *Implements* IDbConnection.ChangeDatabase *See Also* *Note MySqlConnection Class: connector-net-ref-mysqlclient-mysqlconnection, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlconnection-close, Next: connector-net-ref-mysqlclient-mysqlconnection-createcommand, Prev: connector-net-ref-mysqlclient-mysqlconnection-changedatabase, Up: connector-net-ref-mysqlclient-mysqlconnectionmembers 21.2.7.32 `MySqlConnection.Close' Method ........................................ *Syntax: Visual Basic* NotOverridable Public Sub Close() _ _ Implements IDbConnection.Close *Syntax: C#* public void Close(); *Implements* IDbConnection.Close *See Also* *Note MySqlConnection Class: connector-net-ref-mysqlclient-mysqlconnection, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlconnection-createcommand, Next: connector-net-ref-mysqlclient-mysqlconnection-open, Prev: connector-net-ref-mysqlclient-mysqlconnection-close, Up: connector-net-ref-mysqlclient-mysqlconnectionmembers 21.2.7.33 `MySqlConnection.CreateCommand' Method ................................................ *Syntax: Visual Basic* Public Function CreateCommand() As MySqlCommand *Syntax: C#* public MySqlCommand CreateCommand(); *See Also* *Note MySqlConnection Class: connector-net-ref-mysqlclient-mysqlconnection, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlconnection-open, Next: connector-net-ref-mysqlclient-mysqlconnection-ping, Prev: connector-net-ref-mysqlclient-mysqlconnection-createcommand, Up: connector-net-ref-mysqlclient-mysqlconnectionmembers 21.2.7.34 `MySqlConnection.Open' Method ....................................... *Syntax: Visual Basic* NotOverridable Public Sub Open() _ _ Implements IDbConnection.Open *Syntax: C#* public void Open(); *Implements* IDbConnection.Open *See Also* *Note MySqlConnection Class: connector-net-ref-mysqlclient-mysqlconnection, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlconnection-ping, Next: connector-net-ref-mysqlclient-mysqlconnection-infomessage, Prev: connector-net-ref-mysqlclient-mysqlconnection-open, Up: connector-net-ref-mysqlclient-mysqlconnectionmembers 21.2.7.35 `MySqlConnection.Ping' Method ....................................... Ping *Syntax: Visual Basic* Public Function Ping() As Boolean *Syntax: C#* public bool Ping(); *Return Value* *See Also* *Note MySqlConnection Class: connector-net-ref-mysqlclient-mysqlconnection, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlconnection-infomessage, Next: connector-net-ref-mysqlclient-mysqlconnection-statechange, Prev: connector-net-ref-mysqlclient-mysqlconnection-ping, Up: connector-net-ref-mysqlclient-mysqlconnectionmembers 21.2.7.36 `MySqlConnection.InfoMessage' Event ............................................. * Menu: * connector-net-ref-mysqlclient-mysqlinfomessageeventhandler:: `MySqlInfoMessageEventHandler' Delegate *Syntax: Visual Basic* Public Event InfoMessage As MySqlInfoMessageEventHandler *Syntax: C#* public event MySqlInfoMessageEventHandler InfoMessage; *See Also* *Note MySqlConnection Class: connector-net-ref-mysqlclient-mysqlconnection, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlinfomessageeventhandler, Prev: connector-net-ref-mysqlclient-mysqlconnection-infomessage, Up: connector-net-ref-mysqlclient-mysqlconnection-infomessage 21.2.7.37 `MySqlInfoMessageEventHandler' Delegate ................................................. * Menu: * connector-net-ref-mysqlclient-mysqlinfomessageeventargs:: `MySqlInfoMessageEventArgs' Class Represents the method that will handle the *Note InfoMessage: connector-net-ref-mysqlclient-mysqlconnection-infomessage. event of a *Note MySqlConnection: connector-net-ref-mysqlclient-mysqlconnection . *Syntax: Visual Basic* Public Delegate Sub MySqlInfoMessageEventHandler( _ ByVal sender As Object, _ ByVal args As MySqlInfoMessageEventArgs _ ) *Syntax: C#* public delegate void MySqlInfoMessageEventHandler( objectsender, MySqlInfoMessageEventArgsargs ); *Requirements* Namespace: *Note MySql.Data.MySqlClient: connector-net-ref-mysqlclient. Assembly: MySql.Data (in MySql.Data.dll) *See Also* *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlinfomessageeventargs, Prev: connector-net-ref-mysqlclient-mysqlinfomessageeventhandler, Up: connector-net-ref-mysqlclient-mysqlinfomessageeventhandler 21.2.7.38 `MySqlInfoMessageEventArgs' Class ........................................... * Menu: * connector-net-ref-mysqlclient-mysqlinfomessageeventargsmembers:: `MySqlInfoMessageEventArgs' Members Provides data for the InfoMessage event. This class cannot be inherited. For a list of all members of this type, see *Note MySqlInfoMessageEventArgs Members: connector-net-ref-mysqlclient-mysqlinfomessageeventargsmembers . *Syntax: Visual Basic* Public Class MySqlInfoMessageEventArgs_ Inherits EventArgs *Syntax: C#* public class MySqlInfoMessageEventArgs : EventArgs *Thread Safety* Public static (Sharedin Visual Basic) members of this type are safe for multithreaded operations. Instance members are notguaranteed to be thread-safe. *Requirements* Namespace: *Note MySql.Data.MySqlClient: connector-net-ref-mysqlclient. Assembly: MySql.Data (in MySql.Data.dll) *See Also* *Note MySqlInfoMessageEventArgs Members: connector-net-ref-mysqlclient-mysqlinfomessageeventargsmembers, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlinfomessageeventargsmembers, Prev: connector-net-ref-mysqlclient-mysqlinfomessageeventargs, Up: connector-net-ref-mysqlclient-mysqlinfomessageeventargs 21.2.7.39 `MySqlInfoMessageEventArgs' Members ............................................. * Menu: * connector-net-ref-mysqlclient-mysqlinfomessageeventargsconstructor:: `MySqlInfoMessageEventArgs' Constructor * connector-net-ref-mysqlclient-mysqlinfomessageeventargs-errors:: `MySqlInfoMessageEventArgs.errors' Field *Note MySqlInfoMessageEventArgs overview: connector-net-ref-mysqlclient-mysqlinfomessageeventargs. *Public Instance Constructors* *Note MySqlInfoMessageEventArgs Initializes a new instance of the Constructor: *Note MySqlInfoMessageEventArgs: connector-net-ref-mysqlclient-mysqlinfomessageeventargsconstructor.connector-net-ref-mysqlclient-mysqlinfomessageeventargs. class. *Public Instance Fields* *Note errors: connector-net-ref-mysqlclient-mysqlinfomessageeventargs-errors. *Public Instance Methods* Equals(inherited from Object) Determines whether the specified Objectis equal to the current Object. GetHashCode(inherited from Object) Serves as a hash function for a particular type. GetHashCodeis suitable for use in hashing algorithms and data structures like a hash table. GetType(inherited from Object) Gets the Typeof the current instance. ToString(inherited from Object) Returns a Stringthat represents the current Object. *Protected Instance Methods* Finalize(inherited from Object) Allows an Objectto attempt to free resources and perform other cleanup operations before the Objectis reclaimed by garbage collection. MemberwiseClone(inherited from Creates a shallow copy of the Object) current Object. *See Also* *Note MySqlInfoMessageEventArgs Class: connector-net-ref-mysqlclient-mysqlinfomessageeventargs, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlinfomessageeventargsconstructor, Next: connector-net-ref-mysqlclient-mysqlinfomessageeventargs-errors, Prev: connector-net-ref-mysqlclient-mysqlinfomessageeventargsmembers, Up: connector-net-ref-mysqlclient-mysqlinfomessageeventargsmembers 21.2.7.40 `MySqlInfoMessageEventArgs' Constructor ................................................. Initializes a new instance of the *Note MySqlInfoMessageEventArgs: connector-net-ref-mysqlclient-mysqlinfomessageeventargs. class. *Syntax: Visual Basic* Public Sub New() *Syntax: C#* public MySqlInfoMessageEventArgs(); *See Also* *Note MySqlInfoMessageEventArgs Class: connector-net-ref-mysqlclient-mysqlinfomessageeventargs, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlinfomessageeventargs-errors, Prev: connector-net-ref-mysqlclient-mysqlinfomessageeventargsconstructor, Up: connector-net-ref-mysqlclient-mysqlinfomessageeventargsmembers 21.2.7.41 `MySqlInfoMessageEventArgs.errors' Field .................................................. * Menu: * connector-net-ref-mysqlclient-mysqlerror:: `MySqlError' Class *Syntax: Visual Basic* Public errors As MySqlError() *Syntax: C#* public MySqlError[] errors; *See Also* *Note MySqlInfoMessageEventArgs Class: connector-net-ref-mysqlclient-mysqlinfomessageeventargs, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlerror, Prev: connector-net-ref-mysqlclient-mysqlinfomessageeventargs-errors, Up: connector-net-ref-mysqlclient-mysqlinfomessageeventargs-errors 21.2.7.42 `MySqlError' Class ............................ * Menu: * connector-net-ref-mysqlclient-mysqlerrormembers:: `MySqlError' Members Collection of error codes that can be returned by the server For a list of all members of this type, see *Note MySqlError Members: connector-net-ref-mysqlclient-mysqlerrormembers . *Syntax: Visual Basic* Public Class MySqlError *Syntax: C#* public class MySqlError *Thread Safety* Public static (Shared in Visual Basic) members of this type are safe for multithreaded operations. Instance members are not guaranteed to be thread-safe. *Requirements* Namespace: *Note MySql.Data.MySqlClient: connector-net-ref-mysqlclient. Assembly: MySql.Data (in MySql.Data.dll) *See Also* *Note MySqlError Members: connector-net-ref-mysqlclient-mysqlerrormembers, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlerrormembers, Prev: connector-net-ref-mysqlclient-mysqlerror, Up: connector-net-ref-mysqlclient-mysqlerror 21.2.7.43 `MySqlError' Members .............................. * Menu: * connector-net-ref-mysqlclient-mysqlerrorconstructor:: `MySqlError' Constructor * connector-net-ref-mysqlclient-mysqlerror-code:: Code Property * connector-net-ref-mysqlclient-mysqlerror-level:: Level Property * connector-net-ref-mysqlclient-mysqlerror-message:: Message Property *Note MySqlError overview: connector-net-ref-mysqlclient-mysqlerror. *Public Instance Constructors* *Note MySqlError Constructor: connector-net-ref-mysqlclient-mysqlerrorconstructor. *Public Instance Properties* *Note Code: Error code connector-net-ref-mysqlclient-mysqlerror-code. *Note Level: Error level connector-net-ref-mysqlclient-mysqlerror-level. *Note Message: Error message connector-net-ref-mysqlclient-mysqlerror-message. *Public Instance Methods* Equals(inherited from Object) Determines whether the specified Objectis equal to the current Object. GetHashCode(inherited from Object) Serves as a hash function for a particular type. GetHashCodeis suitable for use in hashing algorithms and data structures like a hash table. GetType(inherited from Object) Gets the Typeof the current instance. ToString(inherited from Object) Returns a Stringthat represents the current Object. *Protected Instance Methods* Finalize(inherited from Object) Allows an Objectto attempt to free resources and perform other cleanup operations before the Objectis reclaimed by garbage collection. MemberwiseClone(inherited from Creates a shallow copy of the Object) current Object. *See Also* *Note MySqlError Class: connector-net-ref-mysqlclient-mysqlerror, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlerrorconstructor, Next: connector-net-ref-mysqlclient-mysqlerror-code, Prev: connector-net-ref-mysqlclient-mysqlerrormembers, Up: connector-net-ref-mysqlclient-mysqlerrormembers 21.2.7.44 `MySqlError' Constructor .................................. *Syntax: Visual Basic* Public Sub New( _ ByVal level As String, _ ByVal code As Integer, _ ByVal message As String _ ) *Syntax: C#* public MySqlError( stringlevel, intcode, stringmessage ); *Parameters* * `level': * `code': * `message': *See Also* *Note MySqlError Class: connector-net-ref-mysqlclient-mysqlerror, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlerror-code, Next: connector-net-ref-mysqlclient-mysqlerror-level, Prev: connector-net-ref-mysqlclient-mysqlerrorconstructor, Up: connector-net-ref-mysqlclient-mysqlerrormembers 21.2.7.45 Code Property ....................... Error code *Syntax: Visual Basic* Public ReadOnly Property Code As Integer *Syntax: C#* public int Code {get;} *See Also* *Note MySqlError Class: connector-net-ref-mysqlclient-mysqlerror, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlerror-level, Next: connector-net-ref-mysqlclient-mysqlerror-message, Prev: connector-net-ref-mysqlclient-mysqlerror-code, Up: connector-net-ref-mysqlclient-mysqlerrormembers 21.2.7.46 Level Property ........................ Error level *Syntax: Visual Basic* Public ReadOnly Property Level As String *Syntax: C#* public string Level {get;} *See Also* *Note MySqlError Class: connector-net-ref-mysqlclient-mysqlerror, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlerror-message, Prev: connector-net-ref-mysqlclient-mysqlerror-level, Up: connector-net-ref-mysqlclient-mysqlerrormembers 21.2.7.47 Message Property .......................... Error message *Syntax: Visual Basic* Public ReadOnly Property Message As String *Syntax: C#* public string Message {get;} *See Also* *Note MySqlError Class: connector-net-ref-mysqlclient-mysqlerror, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlconnection-statechange, Prev: connector-net-ref-mysqlclient-mysqlconnection-infomessage, Up: connector-net-ref-mysqlclient-mysqlconnectionmembers 21.2.7.48 `MySqlConnection.StateChange' Event ............................................. *Syntax: Visual Basic* Public Event StateChange As StateChangeEventHandler *Syntax: C#* public event StateChangeEventHandler StateChange; *See Also* *Note MySqlConnection Class: connector-net-ref-mysqlclient-mysqlconnection, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlcommandconstructor4, Prev: connector-net-ref-mysqlclient-mysqlcommandconstructor3, Up: connector-net-ref-mysqlclient-mysqlcommandconstructor 21.2.7.49 `MySqlCommand' Constructor .................................... *Syntax: Visual Basic* Overloads Public Sub New( _ ByVal cmdText As String, _ ByVal connection As MySqlConnection, _ ByVal transaction As MySqlTransaction _ ) *Syntax: C#* public MySqlCommand( stringcmdText, MySqlConnectionconnection, MySqlTransactiontransaction ); *See Also* *Note MySqlCommand Class: connector-net-ref-mysqlclient-mysqlcommand, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note MySqlCommand Constructor Overload List: connector-net-ref-mysqlclient-mysqlcommandconstructor.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlcommand-commandtext, Next: connector-net-ref-mysqlclient-mysqlcommand-commandtimeout, Prev: connector-net-ref-mysqlclient-mysqlcommandconstructor, Up: connector-net-ref-mysqlclient-mysqlcommandmembers 21.2.7.50 CommandText Property .............................. *Syntax: Visual Basic* NotOverridable Public Property CommandText As String _ _ Implements IDbCommand.CommandText *Syntax: C#* public string CommandText {get; set;} *Implements* IDbCommand.CommandText *See Also* *Note MySqlCommand Class: connector-net-ref-mysqlclient-mysqlcommand, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlcommand-commandtimeout, Next: connector-net-ref-mysqlclient-mysqlcommand-commandtype, Prev: connector-net-ref-mysqlclient-mysqlcommand-commandtext, Up: connector-net-ref-mysqlclient-mysqlcommandmembers 21.2.7.51 CommandTimeout Property ................................. *Syntax: Visual Basic* NotOverridable Public Property CommandTimeout As Integer _ _ Implements IDbCommand.CommandTimeout *Syntax: C#* public int CommandTimeout {get; set;} *Implements* IDbCommand.CommandTimeout *See Also* *Note MySqlCommand Class: connector-net-ref-mysqlclient-mysqlcommand, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlcommand-commandtype, Next: connector-net-ref-mysqlclient-mysqlcommand-connection, Prev: connector-net-ref-mysqlclient-mysqlcommand-commandtimeout, Up: connector-net-ref-mysqlclient-mysqlcommandmembers 21.2.7.52 CommandType Property .............................. *Syntax: Visual Basic* NotOverridable Public Property CommandType As CommandType _ _ Implements IDbCommand.CommandType *Syntax: C#* public System.Data.CommandType CommandType {get; set;} *Implements* IDbCommand.CommandType *See Also* *Note MySqlCommand Class: connector-net-ref-mysqlclient-mysqlcommand, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlcommand-connection, Next: connector-net-ref-mysqlclient-mysqlcommand-isprepared, Prev: connector-net-ref-mysqlclient-mysqlcommand-commandtype, Up: connector-net-ref-mysqlclient-mysqlcommandmembers 21.2.7.53 Connection Property ............................. *Syntax: Visual Basic* Public Property Connection As MySqlConnection *Syntax: C#* public MySqlConnection Connection {get; set;} *See Also* *Note MySqlCommand Class: connector-net-ref-mysqlclient-mysqlcommand, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlcommand-isprepared, Next: connector-net-ref-mysqlclient-mysqlcommand-parameters, Prev: connector-net-ref-mysqlclient-mysqlcommand-connection, Up: connector-net-ref-mysqlclient-mysqlcommandmembers 21.2.7.54 IsPrepared Property ............................. *Syntax: Visual Basic* Public ReadOnly Property IsPrepared As Boolean *Syntax: C#* public bool IsPrepared {get;} *See Also* *Note MySqlCommand Class: connector-net-ref-mysqlclient-mysqlcommand, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlcommand-parameters, Next: connector-net-ref-mysqlclient-mysqlcommand-transaction, Prev: connector-net-ref-mysqlclient-mysqlcommand-isprepared, Up: connector-net-ref-mysqlclient-mysqlcommandmembers 21.2.7.55 Parameters Property ............................. * Menu: * connector-net-ref-mysqlclient-mysqlparametercollection:: `MySqlParameterCollection' Class *Syntax: Visual Basic* Public ReadOnly Property Parameters As MySqlParameterCollection *Syntax: C#* public MySqlParameterCollection Parameters {get;} *See Also* *Note MySqlCommand Class: connector-net-ref-mysqlclient-mysqlcommand, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlparametercollection, Prev: connector-net-ref-mysqlclient-mysqlcommand-parameters, Up: connector-net-ref-mysqlclient-mysqlcommand-parameters 21.2.7.56 `MySqlParameterCollection' Class .......................................... * Menu: * connector-net-ref-mysqlclient-mysqlparametercollectionmembers:: `MySqlParameterCollection' Members Represents a collection of parameters relevant to a *Note MySqlCommand: connector-net-ref-mysqlclient-mysqlcommand. as well as their respective mappings to columns in a DataSet. This class cannot be inherited. For a list of all members of this type, see *Note MySqlParameterCollection Members: connector-net-ref-mysqlclient-mysqlparametercollectionmembers . *Syntax: Visual Basic* NotInheritable Public Class MySqlParameterCollection_ Inherits MarshalByRefObject_ Implements IDataParameterCollection, IList, ICollection, IEnumerable *Syntax: C#* public sealed class MySqlParameterCollection : MarshalByRefObject, IDataParameterCollection, IList, ICollection, IEnumerable *Thread Safety* Public static (Shared in Visual Basic) members of this type are safe for multithreaded operations. Instance members are not guaranteed to be thread-safe. *Requirements* Namespace: *Note MySql.Data.MySqlClient: connector-net-ref-mysqlclient. Assembly: MySql.Data (in MySql.Data.dll) *See Also* *Note MySqlParameterCollection Members: connector-net-ref-mysqlclient-mysqlparametercollectionmembers, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlparametercollectionmembers, Prev: connector-net-ref-mysqlclient-mysqlparametercollection, Up: connector-net-ref-mysqlclient-mysqlparametercollection 21.2.7.57 `MySqlParameterCollection' Members ............................................ * Menu: * connector-net-ref-mysqlclient-mysqlparametercollectionconstructor:: `MySqlParameterCollection' Constructor * connector-net-ref-mysqlclient-mysqlparametercollection-count:: Count Property * connector-net-ref-mysqlclient-mysqlparametercollectionitem:: Item Property * connector-net-ref-mysqlclient-mysqlparametercollection-add-overloads:: Add Method * connector-net-ref-mysqlclient-mysqlparametercollection-clear:: `MySqlParameterCollection.Clear' Method * connector-net-ref-mysqlclient-mysqlparametercollection-contains-overloads:: Contains Method * connector-net-ref-mysqlclient-mysqlparametercollection-copyto:: `MySqlParameterCollection.CopyTo' Method * connector-net-ref-mysqlclient-mysqlparametercollection-indexof-overloads:: IndexOf Method * connector-net-ref-mysqlclient-mysqlparametercollection-insert:: `MySqlParameterCollection.Insert' Method * connector-net-ref-mysqlclient-mysqlparametercollection-remove:: `MySqlParameterCollection.Remove' Method * connector-net-ref-mysqlclient-mysqlparametercollection-removeat-overloads:: RemoveAt Method *Note MySqlParameterCollection overview: connector-net-ref-mysqlclient-mysqlparametercollection. *Public Instance Constructors* *Note MySqlParameterCollection Initializes a new instance of the Constructor: *Note MySqlParameterCollection: connector-net-ref-mysqlclient-mysqlparametercollectionconstructor.connector-net-ref-mysqlclient-mysqlparametercollection. class. *Public Instance Properties* *Note Count: Gets the number of MySqlParameter connector-net-ref-mysqlclient-mysqlparametercollection-count.objects in the collection. *Note Item: Overloaded. Gets the *Note connector-net-ref-mysqlclient-mysqlparametercollectionitem.MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. with a specified attribute. In C#, this property is the indexer for the *Note MySqlParameterCollection: connector-net-ref-mysqlclient-mysqlparametercollection. class. *Public Instance Methods* *Note Add: Overloaded. Adds the specified connector-net-ref-mysqlclient-mysqlparametercollection-add-overloads.*Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. object to the *Note MySqlParameterCollection: connector-net-ref-mysqlclient-mysqlparametercollection . *Note Clear: Removes all items from the connector-net-ref-mysqlclient-mysqlparametercollection-clear.collection. *Note Contains: Overloaded. Gets a value indicating connector-net-ref-mysqlclient-mysqlparametercollection-contains-overloads.whether a *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. exists in the collection. *Note CopyTo: Copies MySqlParameter objects from connector-net-ref-mysqlclient-mysqlparametercollection-copyto.the MySqlParameterCollection to the specified array. CreateObjRef(inherited from Creates an object that contains all MarshalByRefObject) the relevant information required to generate a proxy used to communicate with a remote object. Equals(inherited from Object) Determines whether the specified Objectis equal to the current Object. GetHashCode(inherited from Object) Serves as a hash function for a particular type. GetHashCodeis suitable for use in hashing algorithms and data structures like a hash table. GetLifetimeService(inherited from Retrieves the current lifetime MarshalByRefObject) service object that controls the lifetime policy for this instance. GetType(inherited from Object) Gets the Typeof the current instance. *Note IndexOf: Overloaded. Gets the location of a connector-net-ref-mysqlclient-mysqlparametercollection-indexof-overloads.*Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. in the collection. InitializeLifetimeService(inherited Obtains a lifetime service object from MarshalByRefObject) to control the lifetime policy for this instance. *Note Insert: Inserts a MySqlParameter into the connector-net-ref-mysqlclient-mysqlparametercollection-insert.collection at the specified index. *Note Remove: Removes the specified connector-net-ref-mysqlclient-mysqlparametercollection-remove.MySqlParameter from the collection. *Note RemoveAt: Overloaded. Removes the specified connector-net-ref-mysqlclient-mysqlparametercollection-removeat-overloads.*Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. from the collection. ToString(inherited from Object) Returns a Stringthat represents the current Object. *See Also* *Note MySqlParameterCollection Class: connector-net-ref-mysqlclient-mysqlparametercollection, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlparametercollectionconstructor, Next: connector-net-ref-mysqlclient-mysqlparametercollection-count, Prev: connector-net-ref-mysqlclient-mysqlparametercollectionmembers, Up: connector-net-ref-mysqlclient-mysqlparametercollectionmembers 21.2.7.58 `MySqlParameterCollection' Constructor ................................................ Initializes a new instance of the *Note MySqlParameterCollection: connector-net-ref-mysqlclient-mysqlparametercollection. class. *Syntax: Visual Basic* Public Sub New() *Syntax: C#* public MySqlParameterCollection(); *See Also* *Note MySqlParameterCollection Class: connector-net-ref-mysqlclient-mysqlparametercollection, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlparametercollection-count, Next: connector-net-ref-mysqlclient-mysqlparametercollectionitem, Prev: connector-net-ref-mysqlclient-mysqlparametercollectionconstructor, Up: connector-net-ref-mysqlclient-mysqlparametercollectionmembers 21.2.7.59 Count Property ........................ Gets the number of MySqlParameter objects in the collection. *Syntax: Visual Basic* NotOverridable Public ReadOnly Property Count As Integer _ _ Implements ICollection.Count *Syntax: C#* public int Count {get;} *Implements* ICollection.Count *See Also* *Note MySqlParameterCollection Class: connector-net-ref-mysqlclient-mysqlparametercollection, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlparametercollectionitem, Next: connector-net-ref-mysqlclient-mysqlparametercollection-add-overloads, Prev: connector-net-ref-mysqlclient-mysqlparametercollection-count, Up: connector-net-ref-mysqlclient-mysqlparametercollectionmembers 21.2.7.60 Item Property ....................... * Menu: * connector-net-ref-mysqlclient-mysqlparameter:: `MySqlParameter' Class * connector-net-ref-mysqlclient-mysqlparametercollection-item1:: Item Property (Int32) * connector-net-ref-mysqlclient-mysqlparametercollection-item2:: Item Property (String) Gets the *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. with a specified attribute. In C#, this property is the indexer for the *Note MySqlParameterCollection: connector-net-ref-mysqlclient-mysqlparametercollection. class. *Overload List* Gets the *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. at the specified index. * *Note public MySqlParameter this[int] {get; set;}: connector-net-ref-mysqlclient-mysqlparametercollection-item1. Gets the *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. with the specified name. * *Note public MySqlParameter this[string] {get; set;}: connector-net-ref-mysqlclient-mysqlparametercollection-item2. *See Also* *Note MySqlParameterCollection Class: connector-net-ref-mysqlclient-mysqlparametercollection, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlparameter, Next: connector-net-ref-mysqlclient-mysqlparametercollection-item1, Prev: connector-net-ref-mysqlclient-mysqlparametercollectionitem, Up: connector-net-ref-mysqlclient-mysqlparametercollectionitem 21.2.7.61 `MySqlParameter' Class ................................ * Menu: * connector-net-ref-mysqlclient-mysqlparametermembers:: `MySqlParameter' Members Represents a parameter to a *Note MySqlCommand: connector-net-ref-mysqlclient-mysqlcommand , and optionally, its mapping to DataSetcolumns. This class cannot be inherited. For a list of all members of this type, see *Note MySqlParameter Members: connector-net-ref-mysqlclient-mysqlparametermembers . *Syntax: Visual Basic* NotInheritable Public Class MySqlParameter_ Inherits MarshalByRefObject_ Implements IDataParameter, IDbDataParameter, ICloneable *Syntax: C#* public sealed class MySqlParameter : MarshalByRefObject, IDataParameter, IDbDataParameter, ICloneable *Thread Safety* Public static (Shared in Visual Basic) members of this type are safe for multithreaded operations. Instance members are not guaranteed to be thread-safe. *Requirements* Namespace: *Note MySql.Data.MySqlClient: connector-net-ref-mysqlclient. Assembly: MySql.Data (in MySql.Data.dll) *See Also* *Note MySqlParameter Members: connector-net-ref-mysqlclient-mysqlparametermembers, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlparametermembers, Prev: connector-net-ref-mysqlclient-mysqlparameter, Up: connector-net-ref-mysqlclient-mysqlparameter 21.2.7.62 `MySqlParameter' Members .................................. * Menu: * connector-net-ref-mysqlclient-mysqlparameterconstructor:: `MySqlParameter' Constructor * connector-net-ref-mysqlclient-mysqlparameter-dbtype:: DbType Property * connector-net-ref-mysqlclient-mysqlparameter-direction:: Direction Property * connector-net-ref-mysqlclient-mysqlparameter-isnullable:: IsNullable Property * connector-net-ref-mysqlclient-mysqlparameter-isunsigned:: IsUnsigned Property * connector-net-ref-mysqlclient-mysqlparameter-mysqldbtype:: `MySqlDbType' Property * connector-net-ref-mysqlclient-mysqlparameter-parametername:: ParameterName Property * connector-net-ref-mysqlclient-mysqlparameter-precision:: Precision Property * connector-net-ref-mysqlclient-mysqlparameter-scale:: Scale Property * connector-net-ref-mysqlclient-mysqlparameter-size:: Size Property * connector-net-ref-mysqlclient-mysqlparameter-sourcecolumn:: SourceColumn Property * connector-net-ref-mysqlclient-mysqlparameter-sourceversion:: SourceVersion Property * connector-net-ref-mysqlclient-mysqlparameter-tostring:: `MySqlParameter.ToString' Method *Note MySqlParameter overview: connector-net-ref-mysqlclient-mysqlparameter. *Public Instance Constructors* *Note MySqlParameter: Overloaded. Initializes a new connector-net-ref-mysqlclient-mysqlparameterconstructor.instance of the MySqlParameter class. *Public Instance Properties* *Note DbType: Gets or sets the DbTypeof the connector-net-ref-mysqlclient-mysqlparameter-dbtype.parameter. *Note Direction: Gets or sets a value indicating connector-net-ref-mysqlclient-mysqlparameter-direction.whether the parameter is input-only, output-only, bidirectional, or a stored procedure return value parameter. As of MySQL version 4.1 and earlier, input-only is the only valid choice. *Note IsNullable: Gets or sets a value indicating connector-net-ref-mysqlclient-mysqlparameter-isnullable.whether the parameter accepts null values. *Note IsUnsigned: connector-net-ref-mysqlclient-mysqlparameter-isunsigned. *Note MySqlDbType: Gets or sets the MySqlDbType of the connector-net-ref-mysqlclient-mysqlparameter-mysqldbtype.parameter. *Note ParameterName: Gets or sets the name of the connector-net-ref-mysqlclient-mysqlparameter-parametername.MySqlParameter. *Note Precision: Gets or sets the maximum number of connector-net-ref-mysqlclient-mysqlparameter-precision.digits used to represent the *Note Value: connector-net-ref-mysqlclient-mysqlparameter-value. property. *Note Scale: Gets or sets the number of decimal connector-net-ref-mysqlclient-mysqlparameter-scale.places to which *Note Value: connector-net-ref-mysqlclient-mysqlparameter-value. is resolved. *Note Size: Gets or sets the maximum size, in connector-net-ref-mysqlclient-mysqlparameter-size.bytes, of the data within the column. *Note SourceColumn: Gets or sets the name of the source connector-net-ref-mysqlclient-mysqlparameter-sourcecolumn.column that is mapped to the DataSetand used for loading or returning the *Note Value: connector-net-ref-mysqlclient-mysqlparameter-value . *Note SourceVersion: Gets or sets the DataRowVersionto connector-net-ref-mysqlclient-mysqlparameter-sourceversion.use when loading *Note Value: connector-net-ref-mysqlclient-mysqlparameter-value . *Note Value: Gets or sets the value of the connector-net-ref-mysqlclient-mysqlparameter-value.parameter. *Public Instance Methods* CreateObjRef(inherited from Creates an object that contains all MarshalByRefObject) the relevant information required to generate a proxy used to communicate with a remote object. Equals(inherited from Object) Determines whether the specified Objectis equal to the current Object. GetHashCode(inherited from Object) Serves as a hash function for a particular type. GetHashCodeis suitable for use in hashing algorithms and data structures like a hash table. GetLifetimeService(inherited from Retrieves the current lifetime MarshalByRefObject) service object that controls the lifetime policy for this instance. GetType(inherited from Object) Gets the Typeof the current instance. InitializeLifetimeService(inherited Obtains a lifetime service object from MarshalByRefObject) to control the lifetime policy for this instance. *Note ToString: Overridden. Gets a string connector-net-ref-mysqlclient-mysqlparameter-tostring.containing the *Note ParameterName: connector-net-ref-mysqlclient-mysqlparameter-parametername . *See Also* *Note MySqlParameter Class: connector-net-ref-mysqlclient-mysqlparameter, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlparameterconstructor, Next: connector-net-ref-mysqlclient-mysqlparameter-dbtype, Prev: connector-net-ref-mysqlclient-mysqlparametermembers, Up: connector-net-ref-mysqlclient-mysqlparametermembers 21.2.7.63 `MySqlParameter' Constructor ...................................... * Menu: * connector-net-ref-mysqlclient-mysqlparameterconstructor1:: `MySqlParameter' Constructor () * connector-net-ref-mysqlclient-mysqlparameterconstructor3:: `MySqlParameter' Constructor * connector-net-ref-mysqlclient-mysqlparameterconstructor4:: `MySqlParameter' Constructor (String, MySqlDbType, Int32) * connector-net-ref-mysqlclient-mysqlparameterconstructor6:: `MySqlParameter' Constructor * connector-net-ref-mysqlclient-mysqlparameterconstructor5:: `MySqlParameter' Constructor * connector-net-ref-mysqlclient-mysqlparameterconstructor2:: `MySqlParameter' Constructor Initializes a new instance of the MySqlParameter class. *Overload List* Initializes a new instance of the MySqlParameter class. * *Note public MySqlParameter();: connector-net-ref-mysqlclient-mysqlparameterconstructor1. Initializes a new instance of the *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. class with the parameter name and the data type. * *Note public MySqlParameter(string: (MySqlDbType);)connector-net-ref-mysqlclient-mysqlparameterconstructor3. Initializes a new instance of the *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. class with the parameter name, the *Note MySqlDbType: connector-net-ref-mysqlclient-mysqldbtype , and the size. * *Note public MySqlParameter(string: (MySqlDbType)connector-net-ref-mysqlclient-mysqlparameterconstructor4. Initializes a new instance of the *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. class with the parameter name, the type of the parameter, the size of the parameter, a ParameterDirection, the precision of the parameter, the scale of the parameter, the source column, a DataRowVersionto use, and the value of the parameter. * *Note public MySqlParameter(string: (MySqlDbType)connector-net-ref-mysqlclient-mysqlparameterconstructor6.ParameterDirection,bool,byte,byte,string,DataRowVersion,object); Initializes a new instance of the *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. class with the parameter name, the *Note MySqlDbType: connector-net-ref-mysqlclient-mysqldbtype , the size, and the source column name. * *Note public MySqlParameter(string: (MySqlDbType)connector-net-ref-mysqlclient-mysqlparameterconstructor5.string); Initializes a new instance of the *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. class with the parameter name and a value of the new MySqlParameter. * *Note public MySqlParameter(string: (object);)connector-net-ref-mysqlclient-mysqlparameterconstructor2. *See Also* *Note MySqlParameter Class: connector-net-ref-mysqlclient-mysqlparameter, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlparameterconstructor1, Next: connector-net-ref-mysqlclient-mysqlparameterconstructor3, Prev: connector-net-ref-mysqlclient-mysqlparameterconstructor, Up: connector-net-ref-mysqlclient-mysqlparameterconstructor 21.2.7.64 `MySqlParameter' Constructor () ......................................... Initializes a new instance of the MySqlParameter class. *Syntax: Visual Basic* Overloads Public Sub New() *Syntax: C#* public MySqlParameter(); *See Also* *Note MySqlParameter Class: connector-net-ref-mysqlclient-mysqlparameter, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note MySqlParameter Constructor Overload List: connector-net-ref-mysqlclient-mysqlparameterconstructor.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlparameterconstructor3, Next: connector-net-ref-mysqlclient-mysqlparameterconstructor4, Prev: connector-net-ref-mysqlclient-mysqlparameterconstructor1, Up: connector-net-ref-mysqlclient-mysqlparameterconstructor 21.2.7.65 `MySqlParameter' Constructor ...................................... * Menu: * connector-net-ref-mysqlclient-mysqldbtype:: `MySqlDbType' Enumeration Initializes a new instance of the *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. class with the parameter name and the data type. *Syntax: Visual Basic* Overloads Public Sub New( _ ByVal parameterName As String, _ ByVal dbType As MySqlDbType _ ) *Syntax: C#* public MySqlParameter( stringparameterName, MySqlDbTypedbType ); *Parameters* * `parameterName': The name of the parameter to map. * `dbType': One of the *Note MySqlDbType: connector-net-ref-mysqlclient-mysqldbtype. values. *See Also* *Note MySqlParameter Class: connector-net-ref-mysqlclient-mysqlparameter, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note MySqlParameter Constructor Overload List: connector-net-ref-mysqlclient-mysqlparameterconstructor.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqldbtype, Prev: connector-net-ref-mysqlclient-mysqlparameterconstructor3, Up: connector-net-ref-mysqlclient-mysqlparameterconstructor3 21.2.7.66 `MySqlDbType' Enumeration ................................... Specifies MySQL specific data type of a field, property, for use in a *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter . *Syntax: Visual Basic* Public Enum MySqlDbType *Syntax: C#* public enum MySqlDbType *Members* *Member Name* *Description* Newdate Obsolete. Use Datetime or Date type. Timestamp A timestamp. The range is '1970-01-01 00:00:01' to sometime in the year 2038. Time The range is '-838:59:59' to '838:59:59' Date Date The supported range is '1000-01-01' to '9999-12-31' Datetime The supported range is '1000-01-01 00:00:00' to '9999-12-31 23:59:59' Year A year in 2- or 4-digit format (default is 4-digit). The allowable values are 1901 to 2155, 0000 in the 4-digit year format, and 1970-2069 if you use the 2-digit format (70-69). TinyBlob A BLOB column with a maximum length of 255 (2^8 - 1) characters Blob A BLOB column with a maximum length of 65535 (2^16 - 1) characters MediumBlob A BLOB column with a maximum length of 16777215 (2^24 - 1) characters LongBlob A BLOB column with a maximum length of 4294967295 or 4G (2^32 - 1) characters Int16 A 16-bit signed integer. The signed range is -32768 to 32767. The unsigned range is 0 to 65535 Int24 Specifies a 24 (3 byte) signed or unsigned value Int32 A 32-bit signed integer Int64 A 64-bit signed integer Byte The signed range is -128 to 127. The unsigned range is 0 to 255. Float A small (single-precision) floating-point number. Allowable values are -3.402823466E+38 to -1.175494351E-38, 0, and 1.175494351E-38 to 3.402823466E+38. Double A normal-size (double-precision) floating-point number. Allowable values are -1.7976931348623157E+308 to -2.2250738585072014E-308, 0, and 2.2250738585072014E-308 to 1.7976931348623157E+308. UByte An 8-bit unsigned value UInt16 A 16-bit unsigned value UInt24 A 24-bit unsigned value UInt32 A 32-bit unsigned value UInt64 A 64-bit unsigned value Decimal A fixed precision and scale numeric value between -1038 -1 and 10 38 -1 NewDecimal New Decimal Set A set. A string object that can have zero or more values, each of which must be chosen from the list of values 'value1', 'value2', ... A SET can have a maximum of 64 members. String Obsolete Use VarChar type VarChar A variable-length string containing 0 to 255 characters VarString A variable-length string containing 0 to 65535 characters Enum An enumeration. A string object that can have only one value, chosen from the list of values 'value1', 'value2', ..., NULL or the special "" error value. An ENUM can have a maximum of 65535 distinct values. Geometry Bit Bit-field data type TinyText A nonbinary string column supporting a maximum length of 255 (2^8 - 1) characters Text A nonbinary string column supporting a maximum length of 65535 (2^16 - 1) characters MediumText A nonbinary string column supporting a maximum length of 16777215 (2^24 - 1) characters LongText A nonbinary string column supporting a maximum length of 4294967295 (2^32 - 1) characters *Requirements* Namespace: *Note MySql.Data.MySqlClient: connector-net-ref-mysqlclient. Assembly: MySql.Data (in MySql.Data.dll) *See Also* *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlparameterconstructor4, Next: connector-net-ref-mysqlclient-mysqlparameterconstructor6, Prev: connector-net-ref-mysqlclient-mysqlparameterconstructor3, Up: connector-net-ref-mysqlclient-mysqlparameterconstructor 21.2.7.67 `MySqlParameter' Constructor (String, MySqlDbType, Int32) ................................................................... Initializes a new instance of the *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. class with the parameter name, the *Note MySqlDbType: connector-net-ref-mysqlclient-mysqldbtype , and the size. *Syntax: Visual Basic* Overloads Public Sub New( _ ByVal parameterName As String, _ ByVal dbType As MySqlDbType, _ ByVal size As Integer _ ) *Syntax: C#* public MySqlParameter( stringparameterName, MySqlDbTypedbType, intsize ); *Parameters* * `parameterName': The name of the parameter to map. * `dbType': One of the *Note MySqlDbType: connector-net-ref-mysqlclient-mysqldbtype. values. * `size': The length of the parameter. *See Also* *Note MySqlParameter Class: connector-net-ref-mysqlclient-mysqlparameter, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note MySqlParameter Constructor Overload List: connector-net-ref-mysqlclient-mysqlparameterconstructor.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlparameterconstructor6, Next: connector-net-ref-mysqlclient-mysqlparameterconstructor5, Prev: connector-net-ref-mysqlclient-mysqlparameterconstructor4, Up: connector-net-ref-mysqlclient-mysqlparameterconstructor 21.2.7.68 `MySqlParameter' Constructor ...................................... * Menu: * connector-net-ref-mysqlclient-mysqlparameter-value:: Value Property Initializes a new instance of the *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. class with the parameter name, the type of the parameter, the size of the parameter, a ParameterDirection, the precision of the parameter, the scale of the parameter, the source column, a DataRowVersionto use, and the value of the parameter. *Syntax: Visual Basic* Overloads Public Sub New( _ ByVal parameterName As String, _ ByVal dbType As MySqlDbType, _ ByVal size As Integer, _ ByVal direction As ParameterDirection, _ ByVal isNullable As Boolean, _ ByVal precision As Byte, _ ByVal scale As Byte, _ ByVal sourceColumn As String, _ ByVal sourceVersion As DataRowVersion, _ ByVal value As Object _ ) *Syntax: C#* public MySqlParameter( stringparameterName, MySqlDbTypedbType, intsize, ParameterDirectiondirection, boolisNullable, byteprecision, bytescale, stringsourceColumn, DataRowVersionsourceVersion, objectvalue ); *Parameters* * `parameterName': The name of the parameter to map. * `dbType': One of the *Note MySqlDbType: connector-net-ref-mysqlclient-mysqldbtype. values. * `size': The length of the parameter. * `direction': One of the ParameterDirectionvalues. * `isNullable': true if the value of the field can be null, otherwise false. * `precision': The total number of digits to the left and right of the decimal point to which *Note Value: connector-net-ref-mysqlclient-mysqlparameter-value. is resolved. * `scale': The total number of decimal places to which *Note Value: connector-net-ref-mysqlclient-mysqlparameter-value. is resolved. * `sourceColumn': The name of the source column. * `sourceVersion': One of the DataRowVersionvalues. * `value': An Objectthat is the value of the *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter . *Exceptions* *Exception Type* *Condition* ArgumentException *See Also* *Note MySqlParameter Class: connector-net-ref-mysqlclient-mysqlparameter, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note MySqlParameter Constructor Overload List: connector-net-ref-mysqlclient-mysqlparameterconstructor.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlparameter-value, Prev: connector-net-ref-mysqlclient-mysqlparameterconstructor6, Up: connector-net-ref-mysqlclient-mysqlparameterconstructor6 21.2.7.69 Value Property ........................ Gets or sets the value of the parameter. *Syntax: Visual Basic* NotOverridable Public Property Value As Object _ _ Implements IDataParameter.Value *Syntax: C#* public object Value {get; set;} *Implements* IDataParameter.Value *See Also* *Note MySqlParameter Class: connector-net-ref-mysqlclient-mysqlparameter, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlparameterconstructor5, Next: connector-net-ref-mysqlclient-mysqlparameterconstructor2, Prev: connector-net-ref-mysqlclient-mysqlparameterconstructor6, Up: connector-net-ref-mysqlclient-mysqlparameterconstructor 21.2.7.70 `MySqlParameter' Constructor ...................................... Initializes a new instance of the *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. class with the parameter name, the *Note MySqlDbType: connector-net-ref-mysqlclient-mysqldbtype , the size, and the source column name. *Syntax: Visual Basic* Overloads Public Sub New( _ ByVal parameterName As String, _ ByVal dbType As MySqlDbType, _ ByVal size As Integer, _ ByVal sourceColumn As String _ ) *Syntax: C#* public MySqlParameter( stringparameterName, MySqlDbTypedbType, intsize, stringsourceColumn ); *Parameters* * `parameterName': The name of the parameter to map. * `dbType': One of the *Note MySqlDbType: connector-net-ref-mysqlclient-mysqldbtype. values. * `size': The length of the parameter. * `sourceColumn': The name of the source column. *See Also* *Note MySqlParameter Class: connector-net-ref-mysqlclient-mysqlparameter, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note MySqlParameter Constructor Overload List: connector-net-ref-mysqlclient-mysqlparameterconstructor.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlparameterconstructor2, Prev: connector-net-ref-mysqlclient-mysqlparameterconstructor5, Up: connector-net-ref-mysqlclient-mysqlparameterconstructor 21.2.7.71 `MySqlParameter' Constructor ...................................... Initializes a new instance of the *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. class with the parameter name and a value of the new MySqlParameter. *Syntax: Visual Basic* Overloads Public Sub New( _ ByVal parameterName As String, _ ByVal value As Object _ ) *Syntax: C#* public MySqlParameter( stringparameterName, objectvalue ); *Parameters* * `parameterName': The name of the parameter to map. * `value': An Objectthat is the value of the *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter . *See Also* *Note MySqlParameter Class: connector-net-ref-mysqlclient-mysqlparameter, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note MySqlParameter Constructor Overload List: connector-net-ref-mysqlclient-mysqlparameterconstructor.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlparameter-dbtype, Next: connector-net-ref-mysqlclient-mysqlparameter-direction, Prev: connector-net-ref-mysqlclient-mysqlparameterconstructor, Up: connector-net-ref-mysqlclient-mysqlparametermembers 21.2.7.72 DbType Property ......................... Gets or sets the DbTypeof the parameter. *Syntax: Visual Basic* NotOverridable Public Property DbType As DbType _ _ Implements IDataParameter.DbType *Syntax: C#* public System.Data.DbType DbType {get; set;} *Implements* IDataParameter.DbType *See Also* *Note MySqlParameter Class: connector-net-ref-mysqlclient-mysqlparameter, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlparameter-direction, Next: connector-net-ref-mysqlclient-mysqlparameter-isnullable, Prev: connector-net-ref-mysqlclient-mysqlparameter-dbtype, Up: connector-net-ref-mysqlclient-mysqlparametermembers 21.2.7.73 Direction Property ............................ Gets or sets a value indicating whether the parameter is input-only, output-only, bidirectional, or a stored procedure return value parameter. As of MySQL version 4.1 and earlier, input-only is the only valid choice. *Syntax: Visual Basic* NotOverridable Public Property Direction As ParameterDirection _ _ Implements IDataParameter.Direction *Syntax: C#* public System.Data.ParameterDirection Direction {get; set;} *Implements* IDataParameter.Direction *See Also* *Note MySqlParameter Class: connector-net-ref-mysqlclient-mysqlparameter, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlparameter-isnullable, Next: connector-net-ref-mysqlclient-mysqlparameter-isunsigned, Prev: connector-net-ref-mysqlclient-mysqlparameter-direction, Up: connector-net-ref-mysqlclient-mysqlparametermembers 21.2.7.74 IsNullable Property ............................. Gets or sets a value indicating whether the parameter accepts null values. *Syntax: Visual Basic* NotOverridable Public Property IsNullable As Boolean _ _ Implements IDataParameter.IsNullable *Syntax: C#* public bool IsNullable {get; set;} *Implements* IDataParameter.IsNullable *See Also* *Note MySqlParameter Class: connector-net-ref-mysqlclient-mysqlparameter, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlparameter-isunsigned, Next: connector-net-ref-mysqlclient-mysqlparameter-mysqldbtype, Prev: connector-net-ref-mysqlclient-mysqlparameter-isnullable, Up: connector-net-ref-mysqlclient-mysqlparametermembers 21.2.7.75 IsUnsigned Property ............................. *Syntax: Visual Basic* Public Property IsUnsigned As Boolean *Syntax: C#* public bool IsUnsigned {get; set;} *See Also* *Note MySqlParameter Class: connector-net-ref-mysqlclient-mysqlparameter, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlparameter-mysqldbtype, Next: connector-net-ref-mysqlclient-mysqlparameter-parametername, Prev: connector-net-ref-mysqlclient-mysqlparameter-isunsigned, Up: connector-net-ref-mysqlclient-mysqlparametermembers 21.2.7.76 `MySqlDbType' Property ................................ Gets or sets the MySqlDbType of the parameter. *Syntax: Visual Basic* Public Property MySqlDbType As MySqlDbType *Syntax: C#* public MySqlDbType MySqlDbType {get; set;} *See Also* *Note MySqlParameter Class: connector-net-ref-mysqlclient-mysqlparameter, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlparameter-parametername, Next: connector-net-ref-mysqlclient-mysqlparameter-precision, Prev: connector-net-ref-mysqlclient-mysqlparameter-mysqldbtype, Up: connector-net-ref-mysqlclient-mysqlparametermembers 21.2.7.77 ParameterName Property ................................ Gets or sets the name of the MySqlParameter. *Syntax: Visual Basic* NotOverridable Public Property ParameterName As String _ _ Implements IDataParameter.ParameterName *Syntax: C#* public string ParameterName {get; set;} *Implements* IDataParameter.ParameterName *See Also* *Note MySqlParameter Class: connector-net-ref-mysqlclient-mysqlparameter, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlparameter-precision, Next: connector-net-ref-mysqlclient-mysqlparameter-scale, Prev: connector-net-ref-mysqlclient-mysqlparameter-parametername, Up: connector-net-ref-mysqlclient-mysqlparametermembers 21.2.7.78 Precision Property ............................ Gets or sets the maximum number of digits used to represent the *Note Value: connector-net-ref-mysqlclient-mysqlparameter-value. property. *Syntax: Visual Basic* NotOverridable Public Property Precision As Byte _ _ Implements IDbDataParameter.Precision *Syntax: C#* public byte Precision {get; set;} *Implements* IDbDataParameter.Precision *See Also* *Note MySqlParameter Class: connector-net-ref-mysqlclient-mysqlparameter, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlparameter-scale, Next: connector-net-ref-mysqlclient-mysqlparameter-size, Prev: connector-net-ref-mysqlclient-mysqlparameter-precision, Up: connector-net-ref-mysqlclient-mysqlparametermembers 21.2.7.79 Scale Property ........................ Gets or sets the number of decimal places to which *Note Value: connector-net-ref-mysqlclient-mysqlparameter-value. is resolved. *Syntax: Visual Basic* NotOverridable Public Property Scale As Byte _ _ Implements IDbDataParameter.Scale *Syntax: C#* public byte Scale {get; set;} *Implements* IDbDataParameter.Scale *See Also* *Note MySqlParameter Class: connector-net-ref-mysqlclient-mysqlparameter, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlparameter-size, Next: connector-net-ref-mysqlclient-mysqlparameter-sourcecolumn, Prev: connector-net-ref-mysqlclient-mysqlparameter-scale, Up: connector-net-ref-mysqlclient-mysqlparametermembers 21.2.7.80 Size Property ....................... Gets or sets the maximum size, in bytes, of the data within the column. *Syntax: Visual Basic* NotOverridable Public Property Size As Integer _ _ Implements IDbDataParameter.Size *Syntax: C#* public int Size {get; set;} *Implements* IDbDataParameter.Size *See Also* *Note MySqlParameter Class: connector-net-ref-mysqlclient-mysqlparameter, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlparameter-sourcecolumn, Next: connector-net-ref-mysqlclient-mysqlparameter-sourceversion, Prev: connector-net-ref-mysqlclient-mysqlparameter-size, Up: connector-net-ref-mysqlclient-mysqlparametermembers 21.2.7.81 SourceColumn Property ............................... Gets or sets the name of the source column that is mapped to the DataSetand used for loading or returning the *Note Value: connector-net-ref-mysqlclient-mysqlparameter-value . *Syntax: Visual Basic* NotOverridable Public Property SourceColumn As String _ _ Implements IDataParameter.SourceColumn *Syntax: C#* public string SourceColumn {get; set;} *Implements* IDataParameter.SourceColumn *See Also* *Note MySqlParameter Class: connector-net-ref-mysqlclient-mysqlparameter, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlparameter-sourceversion, Next: connector-net-ref-mysqlclient-mysqlparameter-tostring, Prev: connector-net-ref-mysqlclient-mysqlparameter-sourcecolumn, Up: connector-net-ref-mysqlclient-mysqlparametermembers 21.2.7.82 SourceVersion Property ................................ Gets or sets the DataRowVersionto use when loading *Note Value: connector-net-ref-mysqlclient-mysqlparameter-value . *Syntax: Visual Basic* NotOverridable Public Property SourceVersion As DataRowVersion _ _ Implements IDataParameter.SourceVersion *Syntax: C#* public System.Data.DataRowVersion SourceVersion {get; set;} *Implements* IDataParameter.SourceVersion *See Also* *Note MySqlParameter Class: connector-net-ref-mysqlclient-mysqlparameter, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlparameter-tostring, Prev: connector-net-ref-mysqlclient-mysqlparameter-sourceversion, Up: connector-net-ref-mysqlclient-mysqlparametermembers 21.2.7.83 `MySqlParameter.ToString' Method .......................................... Overridden. Gets a string containing the *Note ParameterName: connector-net-ref-mysqlclient-mysqlparameter-parametername . *Syntax: Visual Basic* Overrides Public Function ToString() As String *Syntax: C#* public override string ToString(); *Return Value* *See Also* *Note MySqlParameter Class: connector-net-ref-mysqlclient-mysqlparameter, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlparametercollection-item1, Next: connector-net-ref-mysqlclient-mysqlparametercollection-item2, Prev: connector-net-ref-mysqlclient-mysqlparameter, Up: connector-net-ref-mysqlclient-mysqlparametercollectionitem 21.2.7.84 Item Property (Int32) ............................... Gets the *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. at the specified index. *Syntax: Visual Basic* Overloads Public Default Property Item( _ ByVal index As Integer _ ) As MySqlParameter *Syntax: C#* public MySqlParameter this[ intindex ] {get; set;} *See Also* *Note MySqlParameterCollection Class: connector-net-ref-mysqlclient-mysqlparametercollection, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note MySqlParameterCollection.Item Overload List: connector-net-ref-mysqlclient-mysqlparametercollectionitem.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlparametercollection-item2, Prev: connector-net-ref-mysqlclient-mysqlparametercollection-item1, Up: connector-net-ref-mysqlclient-mysqlparametercollectionitem 21.2.7.85 Item Property (String) ................................ Gets the *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. with the specified name. *Syntax: Visual Basic* Overloads Public Default Property Item( _ ByVal name As String _ ) As MySqlParameter *Syntax: C#* public MySqlParameter this[ stringname ] {get; set;} *See Also* *Note MySqlParameterCollection Class: connector-net-ref-mysqlclient-mysqlparametercollection, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note MySqlParameterCollection.Item Overload List: connector-net-ref-mysqlclient-mysqlparametercollectionitem.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlparametercollection-add-overloads, Next: connector-net-ref-mysqlclient-mysqlparametercollection-clear, Prev: connector-net-ref-mysqlclient-mysqlparametercollectionitem, Up: connector-net-ref-mysqlclient-mysqlparametercollectionmembers 21.2.7.86 Add Method .................... * Menu: * connector-net-ref-mysqlclient-mysqlparametercollection-add-overload-2:: `MySqlParameterCollection.Add' Method * connector-net-ref-mysqlclient-mysqlparametercollection-add-overload-1:: `MySqlParameterCollection.Add' Method * connector-net-ref-mysqlclient-mysqlparametercollection-add-overload-4:: `MySqlParameterCollection.Add' Method * connector-net-ref-mysqlclient-mysqlparametercollection-add-overload-5:: `MySqlParameterCollection.Add' Method * connector-net-ref-mysqlclient-mysqlparametercollection-add-overload-6:: `MySqlParameterCollection.Add' Method * connector-net-ref-mysqlclient-mysqlparametercollection-add-overload-3:: `MySqlParameterCollection.Add' Method Adds the specified *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. object to the *Note MySqlParameterCollection: connector-net-ref-mysqlclient-mysqlparametercollection . *Overload List* Adds the specified *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. object to the *Note MySqlParameterCollection: connector-net-ref-mysqlclient-mysqlparametercollection . * *Note public MySqlParameter Add(MySqlParameter);: connector-net-ref-mysqlclient-mysqlparametercollection-add-overload-2. Adds the specified *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. object to the *Note MySqlParameterCollection: connector-net-ref-mysqlclient-mysqlparametercollection . * *Note public int Add(object);: connector-net-ref-mysqlclient-mysqlparametercollection-add-overload-1. Adds a *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. to the *Note MySqlParameterCollection: connector-net-ref-mysqlclient-mysqlparametercollection. given the parameter name and the data type. * *Note public MySqlParameter Add(string: (MySqlDbType);)connector-net-ref-mysqlclient-mysqlparametercollection-add-overload-4. Adds a *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. to the *Note MySqlParameterCollection: connector-net-ref-mysqlclient-mysqlparametercollection. with the parameter name, the data type, and the column length. * *Note public MySqlParameter Add(string: (MySqlDbType)connector-net-ref-mysqlclient-mysqlparametercollection-add-overload-5. Adds a *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. to the *Note MySqlParameterCollection: connector-net-ref-mysqlclient-mysqlparametercollection. with the parameter name, the data type, the column length, and the source column name. * *Note public MySqlParameter Add(string: (MySqlDbType)connector-net-ref-mysqlclient-mysqlparametercollection-add-overload-6.string); Adds a *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. to the *Note MySqlParameterCollection: connector-net-ref-mysqlclient-mysqlparametercollection. given the specified parameter name and value. * *Note public MySqlParameter Add(string: (object);)connector-net-ref-mysqlclient-mysqlparametercollection-add-overload-3. *See Also* *Note MySqlParameterCollection Class: connector-net-ref-mysqlclient-mysqlparametercollection, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlparametercollection-add-overload-2, Next: connector-net-ref-mysqlclient-mysqlparametercollection-add-overload-1, Prev: connector-net-ref-mysqlclient-mysqlparametercollection-add-overloads, Up: connector-net-ref-mysqlclient-mysqlparametercollection-add-overloads 21.2.7.87 `MySqlParameterCollection.Add' Method ............................................... Adds the specified *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. object to the *Note MySqlParameterCollection: connector-net-ref-mysqlclient-mysqlparametercollection . *Syntax: Visual Basic* Overloads Public Function Add( _ ByVal value As MySqlParameter _ ) As MySqlParameter *Syntax: C#* public MySqlParameter Add( MySqlParametervalue ); *Parameters* * `value': The *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. to add to the collection. *Return Value* The newly added *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. object. *See Also* *Note MySqlParameterCollection Class: connector-net-ref-mysqlclient-mysqlparametercollection, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note MySqlParameterCollection.Add Overload List: connector-net-ref-mysqlclient-mysqlparametercollection-add-overloads.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlparametercollection-add-overload-1, Next: connector-net-ref-mysqlclient-mysqlparametercollection-add-overload-4, Prev: connector-net-ref-mysqlclient-mysqlparametercollection-add-overload-2, Up: connector-net-ref-mysqlclient-mysqlparametercollection-add-overloads 21.2.7.88 `MySqlParameterCollection.Add' Method ............................................... Adds the specified *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. object to the *Note MySqlParameterCollection: connector-net-ref-mysqlclient-mysqlparametercollection . *Syntax: Visual Basic* NotOverridable Overloads Public Function Add( _ ByVal value As Object _ ) As Integer _ _ Implements IList.Add *Syntax: C#* public int Add( objectvalue ); *Parameters* * `value': The *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. to add to the collection. *Return Value* The index of the new *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. object. *Implements* IList.Add *See Also* *Note MySqlParameterCollection Class: connector-net-ref-mysqlclient-mysqlparametercollection, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note MySqlParameterCollection.Add Overload List: connector-net-ref-mysqlclient-mysqlparametercollection-add-overloads.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlparametercollection-add-overload-4, Next: connector-net-ref-mysqlclient-mysqlparametercollection-add-overload-5, Prev: connector-net-ref-mysqlclient-mysqlparametercollection-add-overload-1, Up: connector-net-ref-mysqlclient-mysqlparametercollection-add-overloads 21.2.7.89 `MySqlParameterCollection.Add' Method ............................................... Adds a *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. to the *Note MySqlParameterCollection: connector-net-ref-mysqlclient-mysqlparametercollection. given the parameter name and the data type. *Syntax: Visual Basic* Overloads Public Function Add( _ ByVal parameterName As String, _ ByVal dbType As MySqlDbType _ ) As MySqlParameter *Syntax: C#* public MySqlParameter Add( stringparameterName, MySqlDbTypedbType ); *Parameters* * `parameterName': The name of the parameter. * `dbType': One of the *Note MySqlDbType: connector-net-ref-mysqlclient-mysqldbtype. values. *Return Value* The newly added *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. object. *See Also* *Note MySqlParameterCollection Class: connector-net-ref-mysqlclient-mysqlparametercollection, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note MySqlParameterCollection.Add Overload List: connector-net-ref-mysqlclient-mysqlparametercollection-add-overloads.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlparametercollection-add-overload-5, Next: connector-net-ref-mysqlclient-mysqlparametercollection-add-overload-6, Prev: connector-net-ref-mysqlclient-mysqlparametercollection-add-overload-4, Up: connector-net-ref-mysqlclient-mysqlparametercollection-add-overloads 21.2.7.90 `MySqlParameterCollection.Add' Method ............................................... Adds a *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. to the *Note MySqlParameterCollection: connector-net-ref-mysqlclient-mysqlparametercollection. with the parameter name, the data type, and the column length. *Syntax: Visual Basic* Overloads Public Function Add( _ ByVal parameterName As String, _ ByVal dbType As MySqlDbType, _ ByVal size As Integer _ ) As MySqlParameter *Syntax: C#* public MySqlParameter Add( stringparameterName, MySqlDbTypedbType, intsize ); *Parameters* * `parameterName': The name of the parameter. * `dbType': One of the *Note MySqlDbType: connector-net-ref-mysqlclient-mysqldbtype. values. * `size': The length of the column. *Return Value* The newly added *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. object. *See Also* *Note MySqlParameterCollection Class: connector-net-ref-mysqlclient-mysqlparametercollection, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note MySqlParameterCollection.Add Overload List: connector-net-ref-mysqlclient-mysqlparametercollection-add-overloads.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlparametercollection-add-overload-6, Next: connector-net-ref-mysqlclient-mysqlparametercollection-add-overload-3, Prev: connector-net-ref-mysqlclient-mysqlparametercollection-add-overload-5, Up: connector-net-ref-mysqlclient-mysqlparametercollection-add-overloads 21.2.7.91 `MySqlParameterCollection.Add' Method ............................................... Adds a *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. to the *Note MySqlParameterCollection: connector-net-ref-mysqlclient-mysqlparametercollection. with the parameter name, the data type, the column length, and the source column name. *Syntax: Visual Basic* Overloads Public Function Add( _ ByVal parameterName As String, _ ByVal dbType As MySqlDbType, _ ByVal size As Integer, _ ByVal sourceColumn As String _ ) As MySqlParameter *Syntax: C#* public MySqlParameter Add( stringparameterName, MySqlDbTypedbType, intsize, stringsourceColumn ); *Parameters* * `parameterName': The name of the parameter. * `dbType': One of the *Note MySqlDbType: connector-net-ref-mysqlclient-mysqldbtype. values. * `size': The length of the column. * `sourceColumn': The name of the source column. *Return Value* The newly added *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. object. *See Also* *Note MySqlParameterCollection Class: connector-net-ref-mysqlclient-mysqlparametercollection, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note MySqlParameterCollection.Add Overload List: connector-net-ref-mysqlclient-mysqlparametercollection-add-overloads.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlparametercollection-add-overload-3, Prev: connector-net-ref-mysqlclient-mysqlparametercollection-add-overload-6, Up: connector-net-ref-mysqlclient-mysqlparametercollection-add-overloads 21.2.7.92 `MySqlParameterCollection.Add' Method ............................................... Adds a *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. to the *Note MySqlParameterCollection: connector-net-ref-mysqlclient-mysqlparametercollection. given the specified parameter name and value. *Syntax: Visual Basic* Overloads Public Function Add( _ ByVal parameterName As String, _ ByVal value As Object _ ) As MySqlParameter *Syntax: C#* public MySqlParameter Add( stringparameterName, objectvalue ); *Parameters* * `parameterName': The name of the parameter. * `value': The *Note Value: connector-net-ref-mysqlclient-mysqlparameter-value. of the *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. to add to the collection. *Return Value* The newly added *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. object. *See Also* *Note MySqlParameterCollection Class: connector-net-ref-mysqlclient-mysqlparametercollection, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note MySqlParameterCollection.Add Overload List: connector-net-ref-mysqlclient-mysqlparametercollection-add-overloads.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlparametercollection-clear, Next: connector-net-ref-mysqlclient-mysqlparametercollection-contains-overloads, Prev: connector-net-ref-mysqlclient-mysqlparametercollection-add-overloads, Up: connector-net-ref-mysqlclient-mysqlparametercollectionmembers 21.2.7.93 `MySqlParameterCollection.Clear' Method ................................................. Removes all items from the collection. *Syntax: Visual Basic* NotOverridable Public Sub Clear() _ _ Implements IList.Clear *Syntax: C#* public void Clear(); *Implements* IList.Clear *See Also* *Note MySqlParameterCollection Class: connector-net-ref-mysqlclient-mysqlparametercollection, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlparametercollection-contains-overloads, Next: connector-net-ref-mysqlclient-mysqlparametercollection-copyto, Prev: connector-net-ref-mysqlclient-mysqlparametercollection-clear, Up: connector-net-ref-mysqlclient-mysqlparametercollectionmembers 21.2.7.94 Contains Method ......................... * Menu: * connector-net-ref-mysqlclient-mysqlparametercollection-contains-overload-1:: `MySqlParameterCollection.Contains' Method * connector-net-ref-mysqlclient-mysqlparametercollection-contains-overload-2:: `MySqlParameterCollection.Contains' Method Gets a value indicating whether a *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. exists in the collection. *Overload List* Gets a value indicating whether a MySqlParameter exists in the collection. * *Note public bool Contains(object);: connector-net-ref-mysqlclient-mysqlparametercollection-contains-overload-1. Gets a value indicating whether a *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. with the specified parameter name exists in the collection. * *Note public bool Contains(string);: connector-net-ref-mysqlclient-mysqlparametercollection-contains-overload-2. *See Also* *Note MySqlParameterCollection Class: connector-net-ref-mysqlclient-mysqlparametercollection, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlparametercollection-contains-overload-1, Next: connector-net-ref-mysqlclient-mysqlparametercollection-contains-overload-2, Prev: connector-net-ref-mysqlclient-mysqlparametercollection-contains-overloads, Up: connector-net-ref-mysqlclient-mysqlparametercollection-contains-overloads 21.2.7.95 `MySqlParameterCollection.Contains' Method .................................................... Gets a value indicating whether a MySqlParameter exists in the collection. *Syntax: Visual Basic* NotOverridable Overloads Public Function Contains( _ ByVal value As Object _ ) As Boolean _ _ Implements IList.Contains *Syntax: C#* public bool Contains( objectvalue ); *Parameters* * `value': The value of the *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. object to find. *Return Value* true if the collection contains the *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. object; otherwise, false. *Implements* IList.Contains *See Also* *Note MySqlParameterCollection Class: connector-net-ref-mysqlclient-mysqlparametercollection, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note MySqlParameterCollection.Contains Overload List: connector-net-ref-mysqlclient-mysqlparametercollection-contains-overloads.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlparametercollection-contains-overload-2, Prev: connector-net-ref-mysqlclient-mysqlparametercollection-contains-overload-1, Up: connector-net-ref-mysqlclient-mysqlparametercollection-contains-overloads 21.2.7.96 `MySqlParameterCollection.Contains' Method .................................................... Gets a value indicating whether a *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. with the specified parameter name exists in the collection. *Syntax: Visual Basic* NotOverridable Overloads Public Function Contains( _ ByVal name As String _ ) As Boolean _ _ Implements IDataParameterCollection.Contains *Syntax: C#* public bool Contains( stringname ); *Parameters* * `name': The name of the *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. object to find. *Return Value* true if the collection contains the parameter; otherwise, false. *Implements* IDataParameterCollection.Contains *See Also* *Note MySqlParameterCollection Class: connector-net-ref-mysqlclient-mysqlparametercollection, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note MySqlParameterCollection.Contains Overload List: connector-net-ref-mysqlclient-mysqlparametercollection-contains-overloads.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlparametercollection-copyto, Next: connector-net-ref-mysqlclient-mysqlparametercollection-indexof-overloads, Prev: connector-net-ref-mysqlclient-mysqlparametercollection-contains-overloads, Up: connector-net-ref-mysqlclient-mysqlparametercollectionmembers 21.2.7.97 `MySqlParameterCollection.CopyTo' Method .................................................. Copies MySqlParameter objects from the MySqlParameterCollection to the specified array. *Syntax: Visual Basic* NotOverridable Public Sub CopyTo( _ ByVal array As Array, _ ByVal index As Integer _ ) _ _ Implements ICollection.CopyTo *Syntax: C#* public void CopyTo( Arrayarray, intindex ); *Parameters* * `array': * `index': *Implements* ICollection.CopyTo *See Also* *Note MySqlParameterCollection Class: connector-net-ref-mysqlclient-mysqlparametercollection, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlparametercollection-indexof-overloads, Next: connector-net-ref-mysqlclient-mysqlparametercollection-insert, Prev: connector-net-ref-mysqlclient-mysqlparametercollection-copyto, Up: connector-net-ref-mysqlclient-mysqlparametercollectionmembers 21.2.7.98 IndexOf Method ........................ * Menu: * connector-net-ref-mysqlclient-mysqlparametercollection-indexof-overload-1:: `MySqlParameterCollection.IndexOf' Method * connector-net-ref-mysqlclient-mysqlparametercollection-indexof-overload-2:: `MySqlParameterCollection.IndexOf' Method Gets the location of a *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. in the collection. *Overload List* Gets the location of a *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. in the collection. * *Note public int IndexOf(object);: connector-net-ref-mysqlclient-mysqlparametercollection-indexof-overload-1. Gets the location of the *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. in the collection with a specific parameter name. * *Note public int IndexOf(string);: connector-net-ref-mysqlclient-mysqlparametercollection-indexof-overload-2. *See Also* *Note MySqlParameterCollection Class: connector-net-ref-mysqlclient-mysqlparametercollection, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlparametercollection-indexof-overload-1, Next: connector-net-ref-mysqlclient-mysqlparametercollection-indexof-overload-2, Prev: connector-net-ref-mysqlclient-mysqlparametercollection-indexof-overloads, Up: connector-net-ref-mysqlclient-mysqlparametercollection-indexof-overloads 21.2.7.99 `MySqlParameterCollection.IndexOf' Method ................................................... Gets the location of a *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. in the collection. *Syntax: Visual Basic* NotOverridable Overloads Public Function IndexOf( _ ByVal value As Object _ ) As Integer _ _ Implements IList.IndexOf *Syntax: C#* public int IndexOf( objectvalue ); *Parameters* * `value': The *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. object to locate. *Return Value* The zero-based location of the *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. in the collection. *Implements* IList.IndexOf *See Also* *Note MySqlParameterCollection Class: connector-net-ref-mysqlclient-mysqlparametercollection, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note MySqlParameterCollection.IndexOf Overload List: connector-net-ref-mysqlclient-mysqlparametercollection-indexof-overloads.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlparametercollection-indexof-overload-2, Prev: connector-net-ref-mysqlclient-mysqlparametercollection-indexof-overload-1, Up: connector-net-ref-mysqlclient-mysqlparametercollection-indexof-overloads 21.2.7.100 `MySqlParameterCollection.IndexOf' Method .................................................... Gets the location of the *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. in the collection with a specific parameter name. *Syntax: Visual Basic* NotOverridable Overloads Public Function IndexOf( _ ByVal parameterName As String _ ) As Integer _ _ Implements IDataParameterCollection.IndexOf *Syntax: C#* public int IndexOf( stringparameterName ); *Parameters* * `parameterName': The name of the *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. object to retrieve. *Return Value* The zero-based location of the *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. in the collection. *Implements* IDataParameterCollection.IndexOf *See Also* *Note MySqlParameterCollection Class: connector-net-ref-mysqlclient-mysqlparametercollection, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note MySqlParameterCollection.IndexOf Overload List: connector-net-ref-mysqlclient-mysqlparametercollection-indexof-overloads.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlparametercollection-insert, Next: connector-net-ref-mysqlclient-mysqlparametercollection-remove, Prev: connector-net-ref-mysqlclient-mysqlparametercollection-indexof-overloads, Up: connector-net-ref-mysqlclient-mysqlparametercollectionmembers 21.2.7.101 `MySqlParameterCollection.Insert' Method ................................................... Inserts a MySqlParameter into the collection at the specified index. *Syntax: Visual Basic* NotOverridable Public Sub Insert( _ ByVal index As Integer, _ ByVal value As Object _ ) _ _ Implements IList.Insert *Syntax: C#* public void Insert( intindex, objectvalue ); *Parameters* * `index': * `value': *Implements* IList.Insert *See Also* *Note MySqlParameterCollection Class: connector-net-ref-mysqlclient-mysqlparametercollection, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlparametercollection-remove, Next: connector-net-ref-mysqlclient-mysqlparametercollection-removeat-overloads, Prev: connector-net-ref-mysqlclient-mysqlparametercollection-insert, Up: connector-net-ref-mysqlclient-mysqlparametercollectionmembers 21.2.7.102 `MySqlParameterCollection.Remove' Method ................................................... Removes the specified MySqlParameter from the collection. *Syntax: Visual Basic* NotOverridable Public Sub Remove( _ ByVal value As Object _ ) _ _ Implements IList.Remove *Syntax: C#* public void Remove( objectvalue ); *Parameters* * `value': *Implements* IList.Remove *See Also* *Note MySqlParameterCollection Class: connector-net-ref-mysqlclient-mysqlparametercollection, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlparametercollection-removeat-overloads, Prev: connector-net-ref-mysqlclient-mysqlparametercollection-remove, Up: connector-net-ref-mysqlclient-mysqlparametercollectionmembers 21.2.7.103 RemoveAt Method .......................... * Menu: * connector-net-ref-mysqlclient-mysqlparametercollection-removeat-overload-1:: `MySqlParameterCollection.RemoveAt' Method * connector-net-ref-mysqlclient-mysqlparametercollection-removeat-overload-2:: `MySqlParameterCollection.RemoveAt' Method Removes the specified *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. from the collection. *Overload List* Removes the specified *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. from the collection using a specific index. * *Note public void RemoveAt(int);: connector-net-ref-mysqlclient-mysqlparametercollection-removeat-overload-1. Removes the specified *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. from the collection using the parameter name. * *Note public void RemoveAt(string);: connector-net-ref-mysqlclient-mysqlparametercollection-removeat-overload-2. *See Also* *Note MySqlParameterCollection Class: connector-net-ref-mysqlclient-mysqlparametercollection, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlparametercollection-removeat-overload-1, Next: connector-net-ref-mysqlclient-mysqlparametercollection-removeat-overload-2, Prev: connector-net-ref-mysqlclient-mysqlparametercollection-removeat-overloads, Up: connector-net-ref-mysqlclient-mysqlparametercollection-removeat-overloads 21.2.7.104 `MySqlParameterCollection.RemoveAt' Method ..................................................... Removes the specified *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. from the collection using a specific index. *Syntax: Visual Basic* NotOverridable Overloads Public Sub RemoveAt( _ ByVal index As Integer _ ) _ _ Implements IList.RemoveAt *Syntax: C#* public void RemoveAt( intindex ); *Parameters* * `index': The zero-based index of the parameter. *Implements* IList.RemoveAt *See Also* *Note MySqlParameterCollection Class: connector-net-ref-mysqlclient-mysqlparametercollection, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note MySqlParameterCollection.RemoveAt Overload List: connector-net-ref-mysqlclient-mysqlparametercollection-removeat-overloads.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlparametercollection-removeat-overload-2, Prev: connector-net-ref-mysqlclient-mysqlparametercollection-removeat-overload-1, Up: connector-net-ref-mysqlclient-mysqlparametercollection-removeat-overloads 21.2.7.105 `MySqlParameterCollection.RemoveAt' Method ..................................................... Removes the specified *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. from the collection using the parameter name. *Syntax: Visual Basic* NotOverridable Overloads Public Sub RemoveAt( _ ByVal name As String _ ) _ _ Implements IDataParameterCollection.RemoveAt *Syntax: C#* public void RemoveAt( stringname ); *Parameters* * `name': The name of the *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. object to retrieve. *Implements* IDataParameterCollection.RemoveAt *See Also* *Note MySqlParameterCollection Class: connector-net-ref-mysqlclient-mysqlparametercollection, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note MySqlParameterCollection.RemoveAt Overload List: connector-net-ref-mysqlclient-mysqlparametercollection-removeat-overloads.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlcommand-transaction, Next: connector-net-ref-mysqlclient-mysqlcommand-updatedrowsource, Prev: connector-net-ref-mysqlclient-mysqlcommand-parameters, Up: connector-net-ref-mysqlclient-mysqlcommandmembers 21.2.7.106 Transaction Property ............................... *Syntax: Visual Basic* Public Property Transaction As MySqlTransaction *Syntax: C#* public MySqlTransaction Transaction {get; set;} *See Also* *Note MySqlCommand Class: connector-net-ref-mysqlclient-mysqlcommand, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlcommand-updatedrowsource, Next: connector-net-ref-mysqlclient-mysqlcommand-cancel, Prev: connector-net-ref-mysqlclient-mysqlcommand-transaction, Up: connector-net-ref-mysqlclient-mysqlcommandmembers 21.2.7.107 UpdatedRowSource Property .................................... *Syntax: Visual Basic* NotOverridable Public Property UpdatedRowSource As UpdateRowSource _ _ Implements IDbCommand.UpdatedRowSource *Syntax: C#* public System.Data.UpdateRowSource UpdatedRowSource {get; set;} *Implements* IDbCommand.UpdatedRowSource *See Also* *Note MySqlCommand Class: connector-net-ref-mysqlclient-mysqlcommand, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlcommand-cancel, Next: connector-net-ref-mysqlclient-mysqlcommand-createparameter, Prev: connector-net-ref-mysqlclient-mysqlcommand-updatedrowsource, Up: connector-net-ref-mysqlclient-mysqlcommandmembers 21.2.7.108 `MySqlCommand.Cancel' Method ....................................... Attempts to cancel the execution of a MySqlCommand. This operation is not supported. *Syntax: Visual Basic* NotOverridable Public Sub Cancel() _ _ Implements IDbCommand.Cancel *Syntax: C#* public void Cancel(); *Implements* IDbCommand.Cancel *Remarks* Cancelling an executing command is currently not supported on any version of MySQL. *Exceptions* *Exception Type* *Condition* NotSupportedException This operation is not supported. *See Also* *Note MySqlCommand Class: connector-net-ref-mysqlclient-mysqlcommand, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlcommand-createparameter, Next: connector-net-ref-mysqlclient-mysqlcommand-executenonquery, Prev: connector-net-ref-mysqlclient-mysqlcommand-cancel, Up: connector-net-ref-mysqlclient-mysqlcommandmembers 21.2.7.109 `MySqlCommand.CreateParameter' Method ................................................ Creates a new instance of a *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. object. *Syntax: Visual Basic* Public Function CreateParameter() As MySqlParameter *Syntax: C#* public MySqlParameter CreateParameter(); *Return Value* A *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. object. *Remarks* This method is a strongly-typed version of CreateParameter. *See Also* *Note MySqlCommand Class: connector-net-ref-mysqlclient-mysqlcommand, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlcommand-executenonquery, Next: connector-net-ref-mysqlclient-mysqlcommand-executereader-overloads, Prev: connector-net-ref-mysqlclient-mysqlcommand-createparameter, Up: connector-net-ref-mysqlclient-mysqlcommandmembers 21.2.7.110 `MySqlCommand.ExecuteNonQuery' Method ................................................ *Syntax: Visual Basic* NotOverridable Public Function ExecuteNonQuery() As Integer _ _ Implements IDbCommand.ExecuteNonQuery *Syntax: C#* public int ExecuteNonQuery(); *Implements* IDbCommand.ExecuteNonQuery *See Also* *Note MySqlCommand Class: connector-net-ref-mysqlclient-mysqlcommand, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlcommand-executereader-overloads, Next: connector-net-ref-mysqlclient-mysqlcommand-executescalar, Prev: connector-net-ref-mysqlclient-mysqlcommand-executenonquery, Up: connector-net-ref-mysqlclient-mysqlcommandmembers 21.2.7.111 ExecuteReader Method ............................... * Menu: * connector-net-ref-mysqlclient-mysqlcommand-executereader-overload-1:: `MySqlCommand.ExecuteReader' Method * connector-net-ref-mysqlclient-mysqlcommand-executereader-overload-2:: `MySqlCommand.ExecuteReader' Method *Overload List* * *Note public MySqlDataReader ExecuteReader();: connector-net-ref-mysqlclient-mysqlcommand-executereader-overload-1. * *Note public MySqlDataReader ExecuteReader(CommandBehavior);: connector-net-ref-mysqlclient-mysqlcommand-executereader-overload-2. *See Also* *Note MySqlCommand Class: connector-net-ref-mysqlclient-mysqlcommand, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlcommand-executereader-overload-1, Next: connector-net-ref-mysqlclient-mysqlcommand-executereader-overload-2, Prev: connector-net-ref-mysqlclient-mysqlcommand-executereader-overloads, Up: connector-net-ref-mysqlclient-mysqlcommand-executereader-overloads 21.2.7.112 `MySqlCommand.ExecuteReader' Method .............................................. * Menu: * connector-net-ref-mysqlclient-mysqldatareader:: `MySqlDataReader' Class *Syntax: Visual Basic* Overloads Public Function ExecuteReader() As MySqlDataReader *Syntax: C#* public MySqlDataReader ExecuteReader(); *See Also* *Note MySqlCommand Class: connector-net-ref-mysqlclient-mysqlcommand, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note MySqlCommand.ExecuteReader Overload List: connector-net-ref-mysqlclient-mysqlcommand-executereader-overloads.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqldatareader, Prev: connector-net-ref-mysqlclient-mysqlcommand-executereader-overload-1, Up: connector-net-ref-mysqlclient-mysqlcommand-executereader-overload-1 21.2.7.113 `MySqlDataReader' Class .................................. * Menu: * connector-net-ref-mysqlclient-mysqldatareadermembers:: `MySqlDataReader' Members Provides a means of reading a forward-only stream of rows from a MySQL database. This class cannot be inherited. For a list of all members of this type, see *Note MySqlDataReader Members: connector-net-ref-mysqlclient-mysqldatareadermembers . *Syntax: Visual Basic* NotInheritable Public Class MySqlDataReader_ Inherits MarshalByRefObject_ Implements IEnumerable, IDataReader, IDisposable, IDataRecord *Syntax: C#* public sealed class MySqlDataReader : MarshalByRefObject, IEnumerable, IDataReader, IDisposable, IDataRecord *Thread Safety* Public static (Shared in Visual Basic) members of this type are safe for multithreaded operations. Instance members are not guaranteed to be thread-safe. *Requirements* Namespace: *Note MySql.Data.MySqlClient: connector-net-ref-mysqlclient. Assembly: MySql.Data (in MySql.Data.dll) *See Also* *Note MySqlDataReader Members: connector-net-ref-mysqlclient-mysqldatareadermembers, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqldatareadermembers, Prev: connector-net-ref-mysqlclient-mysqldatareader, Up: connector-net-ref-mysqlclient-mysqldatareader 21.2.7.114 `MySqlDataReader' Members .................................... * Menu: * connector-net-ref-mysqlclient-mysqldatareader-depth:: Depth Property * connector-net-ref-mysqlclient-mysqldatareader-fieldcount:: FieldCount Property * connector-net-ref-mysqlclient-mysqldatareader-hasrows:: HasRows Property * connector-net-ref-mysqlclient-mysqldatareader-isclosed:: IsClosed Property * connector-net-ref-mysqlclient-mysqldatareaderitem:: Item Property * connector-net-ref-mysqlclient-mysqldatareader-recordsaffected:: RecordsAffected Property * connector-net-ref-mysqlclient-mysqldatareader-close:: `MySqlDataReader.Close' Method * connector-net-ref-mysqlclient-mysqldatareader-getboolean:: `MySqlDataReader.GetBoolean' Method * connector-net-ref-mysqlclient-mysqldatareader-getbyte:: `MySqlDataReader.GetByte' Method * connector-net-ref-mysqlclient-mysqldatareader-getbytes:: `MySqlDataReader.GetBytes' Method * connector-net-ref-mysqlclient-mysqldatareader-getchar:: `MySqlDataReader.GetChar' Method * connector-net-ref-mysqlclient-mysqldatareader-getchars:: `MySqlDataReader.GetChars' Method * connector-net-ref-mysqlclient-mysqldatareader-getdatatypename:: `MySqlDataReader.GetDataTypeName' Method * connector-net-ref-mysqlclient-mysqldatareader-getdatetime:: `MySqlDataReader.GetDateTime' Method * connector-net-ref-mysqlclient-mysqldatareader-getdecimal:: `MySqlDataReader.GetDecimal' Method * connector-net-ref-mysqlclient-mysqldatareader-getdouble:: `MySqlDataReader.GetDouble' Method * connector-net-ref-mysqlclient-mysqldatareader-getfieldtype:: `MySqlDataReader.GetFieldType' Method * connector-net-ref-mysqlclient-mysqldatareader-getfloat:: `MySqlDataReader.GetFloat' Method * connector-net-ref-mysqlclient-mysqldatareader-getguid:: `MySqlDataReader.GetGuid' Method * connector-net-ref-mysqlclient-mysqldatareader-getint16:: `MySqlDataReader.GetInt16' Method * connector-net-ref-mysqlclient-mysqldatareader-getint32:: `MySqlDataReader.GetInt32' Method * connector-net-ref-mysqlclient-mysqldatareader-getint64:: `MySqlDataReader.GetInt64' Method * connector-net-ref-mysqlclient-mysqldatareader-getmysqldatetime:: `MySqlDataReader.GetMySqlDateTime' Method * connector-net-ref-mysqlclient-mysqldatareader-getname:: `MySqlDataReader.GetName' Method * connector-net-ref-mysqlclient-mysqldatareader-getordinal:: `MySqlDataReader.GetOrdinal' Method * connector-net-ref-mysqlclient-mysqldatareader-getschematable:: `MySqlDataReader.GetSchemaTable' Method * connector-net-ref-mysqlclient-mysqldatareader-getstring:: `MySqlDataReader.GetString' Method * connector-net-ref-mysqlclient-mysqldatareader-gettimespan:: `MySqlDataReader.GetTimeSpan' Method * connector-net-ref-mysqlclient-mysqldatareader-getuint16:: `MySqlDataReader.GetUInt16' Method * connector-net-ref-mysqlclient-mysqldatareader-getuint32:: `MySqlDataReader.GetUInt32' Method * connector-net-ref-mysqlclient-mysqldatareader-getuint64:: `MySqlDataReader.GetUInt64' Method * connector-net-ref-mysqlclient-mysqldatareader-getvalue:: `MySqlDataReader.GetValue' Method * connector-net-ref-mysqlclient-mysqldatareader-getvalues:: `MySqlDataReader.GetValues' Method * connector-net-ref-mysqlclient-mysqldatareader-isdbnull:: `MySqlDataReader.IsDBNull' Method * connector-net-ref-mysqlclient-mysqldatareader-nextresult:: `MySqlDataReader.NextResult' Method * connector-net-ref-mysqlclient-mysqldatareader-read:: `MySqlDataReader.Read' Method *Note MySqlDataReader overview: connector-net-ref-mysqlclient-mysqldatareader. *Public Instance Properties* *Note Depth: Gets a value indicating the depth connector-net-ref-mysqlclient-mysqldatareader-depth.of nesting for the current row. This method is not supported currently and always returns 0. *Note FieldCount: Gets the number of columns in the connector-net-ref-mysqlclient-mysqldatareader-fieldcount.current row. *Note HasRows: Gets a value indicating whether the connector-net-ref-mysqlclient-mysqldatareader-hasrows.MySqlDataReader contains one or more rows. *Note IsClosed: Gets a value indicating whether the connector-net-ref-mysqlclient-mysqldatareader-isclosed.data reader is closed. *Note Item: Overloaded. Overloaded. Gets the connector-net-ref-mysqlclient-mysqldatareaderitem.value of a column in its native format. In C#, this property is the indexer for the MySqlDataReader class. *Note RecordsAffected: Gets the number of rows changed, connector-net-ref-mysqlclient-mysqldatareader-recordsaffected.inserted, or deleted by execution of the SQL statement. *Public Instance Methods* *Note Close: Closes the MySqlDataReader object. connector-net-ref-mysqlclient-mysqldatareader-close. CreateObjRef(inherited from Creates an object that contains all MarshalByRefObject) the relevant information required to generate a proxy used to communicate with a remote object. Equals(inherited from Object) Determines whether the specified Objectis equal to the current Object. *Note GetBoolean: Gets the value of the specified connector-net-ref-mysqlclient-mysqldatareader-getboolean.column as a Boolean. *Note GetByte: Gets the value of the specified connector-net-ref-mysqlclient-mysqldatareader-getbyte.column as a byte. *Note GetBytes: Reads a stream of bytes from the connector-net-ref-mysqlclient-mysqldatareader-getbytes.specified column offset into the buffer an array starting at the given buffer offset. *Note GetChar: Gets the value of the specified connector-net-ref-mysqlclient-mysqldatareader-getchar.column as a single character. *Note GetChars: Reads a stream of characters from connector-net-ref-mysqlclient-mysqldatareader-getchars.the specified column offset into the buffer as an array starting at the given buffer offset. *Note GetDataTypeName: Gets the name of the source data connector-net-ref-mysqlclient-mysqldatareader-getdatatypename.type. *Note GetDateTime: connector-net-ref-mysqlclient-mysqldatareader-getdatetime. *Note GetDecimal: connector-net-ref-mysqlclient-mysqldatareader-getdecimal. *Note GetDouble: connector-net-ref-mysqlclient-mysqldatareader-getdouble. *Note GetFieldType: Gets the Type that is the data type connector-net-ref-mysqlclient-mysqldatareader-getfieldtype.of the object. *Note GetFloat: connector-net-ref-mysqlclient-mysqldatareader-getfloat. *Note GetGuid: connector-net-ref-mysqlclient-mysqldatareader-getguid. GetHashCode(inherited from Object) Serves as a hash function for a particular type. GetHashCodeis suitable for use in hashing algorithms and data structures like a hash table. *Note GetInt16: connector-net-ref-mysqlclient-mysqldatareader-getint16. *Note GetInt32: connector-net-ref-mysqlclient-mysqldatareader-getint32. *Note GetInt64: connector-net-ref-mysqlclient-mysqldatareader-getint64. GetLifetimeService(inherited from Retrieves the current lifetime MarshalByRefObject) service object that controls the lifetime policy for this instance. *Note GetMySqlDateTime: connector-net-ref-mysqlclient-mysqldatareader-getmysqldatetime. *Note GetName: Gets the name of the specified connector-net-ref-mysqlclient-mysqldatareader-getname.column. *Note GetOrdinal: Gets the column ordinal, given the connector-net-ref-mysqlclient-mysqldatareader-getordinal.name of the column. *Note GetSchemaTable: Returns a DataTable that describes connector-net-ref-mysqlclient-mysqldatareader-getschematable.the column metadata of the MySqlDataReader. *Note GetString: connector-net-ref-mysqlclient-mysqldatareader-getstring. *Note GetTimeSpan: connector-net-ref-mysqlclient-mysqldatareader-gettimespan. GetType(inherited from Object) Gets the Typeof the current instance. *Note GetUInt16: connector-net-ref-mysqlclient-mysqldatareader-getuint16. *Note GetUInt32: connector-net-ref-mysqlclient-mysqldatareader-getuint32. *Note GetUInt64: connector-net-ref-mysqlclient-mysqldatareader-getuint64. *Note GetValue: Gets the value of the specified connector-net-ref-mysqlclient-mysqldatareader-getvalue.column in its native format. *Note GetValues: Gets all attribute columns in the connector-net-ref-mysqlclient-mysqldatareader-getvalues.collection for the current row. InitializeLifetimeService(inherited Obtains a lifetime service object from MarshalByRefObject) to control the lifetime policy for this instance. *Note IsDBNull: Gets a value indicating whether the connector-net-ref-mysqlclient-mysqldatareader-isdbnull.column contains non-existent or missing values. *Note NextResult: Advances the data reader to the connector-net-ref-mysqlclient-mysqldatareader-nextresult.next result, when reading the results of batch SQL statements. *Note Read: Advances the MySqlDataReader to the connector-net-ref-mysqlclient-mysqldatareader-read.next record. ToString(inherited from Object) Returns a Stringthat represents the current Object. *See Also* *Note MySqlDataReader Class: connector-net-ref-mysqlclient-mysqldatareader, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqldatareader-depth, Next: connector-net-ref-mysqlclient-mysqldatareader-fieldcount, Prev: connector-net-ref-mysqlclient-mysqldatareadermembers, Up: connector-net-ref-mysqlclient-mysqldatareadermembers 21.2.7.115 Depth Property ......................... Gets a value indicating the depth of nesting for the current row. This method is not supported currently and always returns 0. *Syntax: Visual Basic* NotOverridable Public ReadOnly Property Depth As Integer _ _ Implements IDataReader.Depth *Syntax: C#* public int Depth {get;} *Implements* IDataReader.Depth *See Also* *Note MySqlDataReader Class: connector-net-ref-mysqlclient-mysqldatareader, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqldatareader-fieldcount, Next: connector-net-ref-mysqlclient-mysqldatareader-hasrows, Prev: connector-net-ref-mysqlclient-mysqldatareader-depth, Up: connector-net-ref-mysqlclient-mysqldatareadermembers 21.2.7.116 FieldCount Property .............................. Gets the number of columns in the current row. *Syntax: Visual Basic* NotOverridable Public ReadOnly Property FieldCount As Integer _ _ Implements IDataRecord.FieldCount *Syntax: C#* public int FieldCount {get;} *Implements* IDataRecord.FieldCount *See Also* *Note MySqlDataReader Class: connector-net-ref-mysqlclient-mysqldatareader, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqldatareader-hasrows, Next: connector-net-ref-mysqlclient-mysqldatareader-isclosed, Prev: connector-net-ref-mysqlclient-mysqldatareader-fieldcount, Up: connector-net-ref-mysqlclient-mysqldatareadermembers 21.2.7.117 HasRows Property ........................... Gets a value indicating whether the MySqlDataReader contains one or more rows. *Syntax: Visual Basic* Public ReadOnly Property HasRows As Boolean *Syntax: C#* public bool HasRows {get;} *See Also* *Note MySqlDataReader Class: connector-net-ref-mysqlclient-mysqldatareader, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqldatareader-isclosed, Next: connector-net-ref-mysqlclient-mysqldatareaderitem, Prev: connector-net-ref-mysqlclient-mysqldatareader-hasrows, Up: connector-net-ref-mysqlclient-mysqldatareadermembers 21.2.7.118 IsClosed Property ............................ Gets a value indicating whether the data reader is closed. *Syntax: Visual Basic* NotOverridable Public ReadOnly Property IsClosed As Boolean _ _ Implements IDataReader.IsClosed *Syntax: C#* public bool IsClosed {get;} *Implements* IDataReader.IsClosed *See Also* *Note MySqlDataReader Class: connector-net-ref-mysqlclient-mysqldatareader, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqldatareaderitem, Next: connector-net-ref-mysqlclient-mysqldatareader-recordsaffected, Prev: connector-net-ref-mysqlclient-mysqldatareader-isclosed, Up: connector-net-ref-mysqlclient-mysqldatareadermembers 21.2.7.119 Item Property ........................ * Menu: * connector-net-ref-mysqlclient-mysqldatareader-item1:: Item Property (Int32) * connector-net-ref-mysqlclient-mysqldatareader-item2:: Item Property (String) Overloaded. Gets the value of a column in its native format. In C#, this property is the indexer for the MySqlDataReader class. *Overload List* Overloaded. Gets the value of a column in its native format. In C#, this property is the indexer for the MySqlDataReader class. * *Note public object this[int] {get;}: connector-net-ref-mysqlclient-mysqldatareader-item1. Gets the value of a column in its native format. In C#, this property is the indexer for the MySqlDataReader class. * *Note public object this[string] {get;}: connector-net-ref-mysqlclient-mysqldatareader-item2. *See Also* *Note MySqlDataReader Class: connector-net-ref-mysqlclient-mysqldatareader, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqldatareader-item1, Next: connector-net-ref-mysqlclient-mysqldatareader-item2, Prev: connector-net-ref-mysqlclient-mysqldatareaderitem, Up: connector-net-ref-mysqlclient-mysqldatareaderitem 21.2.7.120 Item Property (Int32) ................................ Overloaded. Gets the value of a column in its native format. In C#, this property is the indexer for the MySqlDataReader class. *Syntax: Visual Basic* NotOverridable Overloads Public Default ReadOnly Property Item( _ ByVal i As Integer _ ) _ _ Implements IDataRecord.Item As Object _ _ Implements IDataRecord.Item *Syntax: C#* public object this[ inti ] {get;} *Implements* IDataRecord.Item *See Also* *Note MySqlDataReader Class: connector-net-ref-mysqlclient-mysqldatareader, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note MySqlDataReader.Item Overload List: connector-net-ref-mysqlclient-mysqldatareaderitem.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqldatareader-item2, Prev: connector-net-ref-mysqlclient-mysqldatareader-item1, Up: connector-net-ref-mysqlclient-mysqldatareaderitem 21.2.7.121 Item Property (String) ................................. Gets the value of a column in its native format. In C#, this property is the indexer for the MySqlDataReader class. *Syntax: Visual Basic* NotOverridable Overloads Public Default ReadOnly Property Item( _ ByVal name As String _ ) _ _ Implements IDataRecord.Item As Object _ _ Implements IDataRecord.Item *Syntax: C#* public object this[ stringname ] {get;} *Implements* IDataRecord.Item *See Also* *Note MySqlDataReader Class: connector-net-ref-mysqlclient-mysqldatareader, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note MySqlDataReader.Item Overload List: connector-net-ref-mysqlclient-mysqldatareaderitem.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqldatareader-recordsaffected, Next: connector-net-ref-mysqlclient-mysqldatareader-close, Prev: connector-net-ref-mysqlclient-mysqldatareaderitem, Up: connector-net-ref-mysqlclient-mysqldatareadermembers 21.2.7.122 RecordsAffected Property ................................... Gets the number of rows changed, inserted, or deleted by execution of the SQL statement. *Syntax: Visual Basic* NotOverridable Public ReadOnly Property RecordsAffected As Integer _ _ Implements IDataReader.RecordsAffected *Syntax: C#* public int RecordsAffected {get;} *Implements* IDataReader.RecordsAffected *See Also* *Note MySqlDataReader Class: connector-net-ref-mysqlclient-mysqldatareader, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqldatareader-close, Next: connector-net-ref-mysqlclient-mysqldatareader-getboolean, Prev: connector-net-ref-mysqlclient-mysqldatareader-recordsaffected, Up: connector-net-ref-mysqlclient-mysqldatareadermembers 21.2.7.123 `MySqlDataReader.Close' Method ......................................... Closes the MySqlDataReader object. *Syntax: Visual Basic* NotOverridable Public Sub Close() _ _ Implements IDataReader.Close *Syntax: C#* public void Close(); *Implements* IDataReader.Close *See Also* *Note MySqlDataReader Class: connector-net-ref-mysqlclient-mysqldatareader, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqldatareader-getboolean, Next: connector-net-ref-mysqlclient-mysqldatareader-getbyte, Prev: connector-net-ref-mysqlclient-mysqldatareader-close, Up: connector-net-ref-mysqlclient-mysqldatareadermembers 21.2.7.124 `MySqlDataReader.GetBoolean' Method .............................................. Gets the value of the specified column as a Boolean. *Syntax: Visual Basic* NotOverridable Public Function GetBoolean( _ ByVal i As Integer _ ) As Boolean _ _ Implements IDataRecord.GetBoolean *Syntax: C#* public bool GetBoolean( inti ); *Parameters* * `i': *Return Value* *Implements* IDataRecord.GetBoolean *See Also* *Note MySqlDataReader Class: connector-net-ref-mysqlclient-mysqldatareader, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqldatareader-getbyte, Next: connector-net-ref-mysqlclient-mysqldatareader-getbytes, Prev: connector-net-ref-mysqlclient-mysqldatareader-getboolean, Up: connector-net-ref-mysqlclient-mysqldatareadermembers 21.2.7.125 `MySqlDataReader.GetByte' Method ........................................... Gets the value of the specified column as a byte. *Syntax: Visual Basic* NotOverridable Public Function GetByte( _ ByVal i As Integer _ ) As Byte _ _ Implements IDataRecord.GetByte *Syntax: C#* public byte GetByte( inti ); *Parameters* * `i': *Return Value* *Implements* IDataRecord.GetByte *See Also* *Note MySqlDataReader Class: connector-net-ref-mysqlclient-mysqldatareader, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqldatareader-getbytes, Next: connector-net-ref-mysqlclient-mysqldatareader-getchar, Prev: connector-net-ref-mysqlclient-mysqldatareader-getbyte, Up: connector-net-ref-mysqlclient-mysqldatareadermembers 21.2.7.126 `MySqlDataReader.GetBytes' Method ............................................ Reads a stream of bytes from the specified column offset into the buffer an array starting at the given buffer offset. *Syntax: Visual Basic* NotOverridable Public Function GetBytes( _ ByVal i As Integer, _ ByVal dataIndex As Long, _ ByVal buffer As Byte(), _ ByVal bufferIndex As Integer, _ ByVal length As Integer _ ) As Long _ _ Implements IDataRecord.GetBytes *Syntax: C#* public long GetBytes( inti, longdataIndex, byte[]buffer, intbufferIndex, intlength ); *Parameters* * `i': The zero-based column ordinal. * `dataIndex': The index within the field from which to begin the read operation. * `buffer': The buffer into which to read the stream of bytes. * `bufferIndex': The index for buffer to begin the read operation. * `length': The maximum length to copy into the buffer. *Return Value* The actual number of bytes read. *Implements* IDataRecord.GetBytes *See Also* *Note MySqlDataReader Class: connector-net-ref-mysqlclient-mysqldatareader, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqldatareader-getchar, Next: connector-net-ref-mysqlclient-mysqldatareader-getchars, Prev: connector-net-ref-mysqlclient-mysqldatareader-getbytes, Up: connector-net-ref-mysqlclient-mysqldatareadermembers 21.2.7.127 `MySqlDataReader.GetChar' Method ........................................... Gets the value of the specified column as a single character. *Syntax: Visual Basic* NotOverridable Public Function GetChar( _ ByVal i As Integer _ ) As Char _ _ Implements IDataRecord.GetChar *Syntax: C#* public char GetChar( inti ); *Parameters* * `i': *Return Value* *Implements* IDataRecord.GetChar *See Also* *Note MySqlDataReader Class: connector-net-ref-mysqlclient-mysqldatareader, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqldatareader-getchars, Next: connector-net-ref-mysqlclient-mysqldatareader-getdatatypename, Prev: connector-net-ref-mysqlclient-mysqldatareader-getchar, Up: connector-net-ref-mysqlclient-mysqldatareadermembers 21.2.7.128 `MySqlDataReader.GetChars' Method ............................................ Reads a stream of characters from the specified column offset into the buffer as an array starting at the given buffer offset. *Syntax: Visual Basic* NotOverridable Public Function GetChars( _ ByVal i As Integer, _ ByVal fieldOffset As Long, _ ByVal buffer As Char(), _ ByVal bufferoffset As Integer, _ ByVal length As Integer _ ) As Long _ _ Implements IDataRecord.GetChars *Syntax: C#* public long GetChars( inti, longfieldOffset, char[]buffer, intbufferoffset, intlength ); *Parameters* * `i': * `fieldOffset': * `buffer': * `bufferoffset': * `length': *Return Value* *Implements* IDataRecord.GetChars *See Also* *Note MySqlDataReader Class: connector-net-ref-mysqlclient-mysqldatareader, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqldatareader-getdatatypename, Next: connector-net-ref-mysqlclient-mysqldatareader-getdatetime, Prev: connector-net-ref-mysqlclient-mysqldatareader-getchars, Up: connector-net-ref-mysqlclient-mysqldatareadermembers 21.2.7.129 `MySqlDataReader.GetDataTypeName' Method ................................................... Gets the name of the source data type. *Syntax: Visual Basic* NotOverridable Public Function GetDataTypeName( _ ByVal i As Integer _ ) As String _ _ Implements IDataRecord.GetDataTypeName *Syntax: C#* public string GetDataTypeName( inti ); *Parameters* * `i': *Return Value* *Implements* IDataRecord.GetDataTypeName *See Also* *Note MySqlDataReader Class: connector-net-ref-mysqlclient-mysqldatareader, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqldatareader-getdatetime, Next: connector-net-ref-mysqlclient-mysqldatareader-getdecimal, Prev: connector-net-ref-mysqlclient-mysqldatareader-getdatatypename, Up: connector-net-ref-mysqlclient-mysqldatareadermembers 21.2.7.130 `MySqlDataReader.GetDateTime' Method ............................................... *Syntax: Visual Basic* NotOverridable Public Function GetDateTime( _ ByVal index As Integer _ ) As Date _ _ Implements IDataRecord.GetDateTime *Syntax: C#* public DateTime GetDateTime( intindex ); *Implements* IDataRecord.GetDateTime *See Also* *Note MySqlDataReader Class: connector-net-ref-mysqlclient-mysqldatareader, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqldatareader-getdecimal, Next: connector-net-ref-mysqlclient-mysqldatareader-getdouble, Prev: connector-net-ref-mysqlclient-mysqldatareader-getdatetime, Up: connector-net-ref-mysqlclient-mysqldatareadermembers 21.2.7.131 `MySqlDataReader.GetDecimal' Method .............................................. *Syntax: Visual Basic* NotOverridable Public Function GetDecimal( _ ByVal index As Integer _ ) As Decimal _ _ Implements IDataRecord.GetDecimal *Syntax: C#* public decimal GetDecimal( intindex ); *Implements* IDataRecord.GetDecimal *See Also* *Note MySqlDataReader Class: connector-net-ref-mysqlclient-mysqldatareader, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqldatareader-getdouble, Next: connector-net-ref-mysqlclient-mysqldatareader-getfieldtype, Prev: connector-net-ref-mysqlclient-mysqldatareader-getdecimal, Up: connector-net-ref-mysqlclient-mysqldatareadermembers 21.2.7.132 `MySqlDataReader.GetDouble' Method ............................................. *Syntax: Visual Basic* NotOverridable Public Function GetDouble( _ ByVal index As Integer _ ) As Double _ _ Implements IDataRecord.GetDouble *Syntax: C#* public double GetDouble( intindex ); *Implements* IDataRecord.GetDouble *See Also* *Note MySqlDataReader Class: connector-net-ref-mysqlclient-mysqldatareader, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqldatareader-getfieldtype, Next: connector-net-ref-mysqlclient-mysqldatareader-getfloat, Prev: connector-net-ref-mysqlclient-mysqldatareader-getdouble, Up: connector-net-ref-mysqlclient-mysqldatareadermembers 21.2.7.133 `MySqlDataReader.GetFieldType' Method ................................................ Gets the Type that is the data type of the object. *Syntax: Visual Basic* NotOverridable Public Function GetFieldType( _ ByVal i As Integer _ ) As Type _ _ Implements IDataRecord.GetFieldType *Syntax: C#* public Type GetFieldType( inti ); *Parameters* * `i': *Return Value* *Implements* IDataRecord.GetFieldType *See Also* *Note MySqlDataReader Class: connector-net-ref-mysqlclient-mysqldatareader, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqldatareader-getfloat, Next: connector-net-ref-mysqlclient-mysqldatareader-getguid, Prev: connector-net-ref-mysqlclient-mysqldatareader-getfieldtype, Up: connector-net-ref-mysqlclient-mysqldatareadermembers 21.2.7.134 `MySqlDataReader.GetFloat' Method ............................................ *Syntax: Visual Basic* NotOverridable Public Function GetFloat( _ ByVal index As Integer _ ) As Single _ _ Implements IDataRecord.GetFloat *Syntax: C#* public float GetFloat( intindex ); *Implements* IDataRecord.GetFloat *See Also* *Note MySqlDataReader Class: connector-net-ref-mysqlclient-mysqldatareader, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqldatareader-getguid, Next: connector-net-ref-mysqlclient-mysqldatareader-getint16, Prev: connector-net-ref-mysqlclient-mysqldatareader-getfloat, Up: connector-net-ref-mysqlclient-mysqldatareadermembers 21.2.7.135 `MySqlDataReader.GetGuid' Method ........................................... *Syntax: Visual Basic* NotOverridable Public Function GetGuid( _ ByVal index As Integer _ ) As Guid _ _ Implements IDataRecord.GetGuid *Syntax: C#* public Guid GetGuid( intindex ); *Implements* IDataRecord.GetGuid *See Also* *Note MySqlDataReader Class: connector-net-ref-mysqlclient-mysqldatareader, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqldatareader-getint16, Next: connector-net-ref-mysqlclient-mysqldatareader-getint32, Prev: connector-net-ref-mysqlclient-mysqldatareader-getguid, Up: connector-net-ref-mysqlclient-mysqldatareadermembers 21.2.7.136 `MySqlDataReader.GetInt16' Method ............................................ *Syntax: Visual Basic* NotOverridable Public Function GetInt16( _ ByVal index As Integer _ ) As Short _ _ Implements IDataRecord.GetInt16 *Syntax: C#* public short GetInt16( intindex ); *Implements* IDataRecord.GetInt16 *See Also* *Note MySqlDataReader Class: connector-net-ref-mysqlclient-mysqldatareader, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqldatareader-getint32, Next: connector-net-ref-mysqlclient-mysqldatareader-getint64, Prev: connector-net-ref-mysqlclient-mysqldatareader-getint16, Up: connector-net-ref-mysqlclient-mysqldatareadermembers 21.2.7.137 `MySqlDataReader.GetInt32' Method ............................................ *Syntax: Visual Basic* NotOverridable Public Function GetInt32( _ ByVal index As Integer _ ) As Integer _ _ Implements IDataRecord.GetInt32 *Syntax: C#* public int GetInt32( intindex ); *Implements* IDataRecord.GetInt32 *See Also* *Note MySqlDataReader Class: connector-net-ref-mysqlclient-mysqldatareader, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqldatareader-getint64, Next: connector-net-ref-mysqlclient-mysqldatareader-getmysqldatetime, Prev: connector-net-ref-mysqlclient-mysqldatareader-getint32, Up: connector-net-ref-mysqlclient-mysqldatareadermembers 21.2.7.138 `MySqlDataReader.GetInt64' Method ............................................ *Syntax: Visual Basic* NotOverridable Public Function GetInt64( _ ByVal index As Integer _ ) As Long _ _ Implements IDataRecord.GetInt64 *Syntax: C#* public long GetInt64( intindex ); *Implements* IDataRecord.GetInt64 *See Also* *Note MySqlDataReader Class: connector-net-ref-mysqlclient-mysqldatareader, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqldatareader-getmysqldatetime, Next: connector-net-ref-mysqlclient-mysqldatareader-getname, Prev: connector-net-ref-mysqlclient-mysqldatareader-getint64, Up: connector-net-ref-mysqlclient-mysqldatareadermembers 21.2.7.139 `MySqlDataReader.GetMySqlDateTime' Method .................................................... *Syntax: Visual Basic* Public Function GetMySqlDateTime( _ ByVal index As Integer _ ) As MySqlDateTime *Syntax: C#* public MySqlDateTime GetMySqlDateTime( intindex ); *See Also* *Note MySqlDataReader Class: connector-net-ref-mysqlclient-mysqldatareader, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqldatareader-getname, Next: connector-net-ref-mysqlclient-mysqldatareader-getordinal, Prev: connector-net-ref-mysqlclient-mysqldatareader-getmysqldatetime, Up: connector-net-ref-mysqlclient-mysqldatareadermembers 21.2.7.140 `MySqlDataReader.GetName' Method ........................................... Gets the name of the specified column. *Syntax: Visual Basic* NotOverridable Public Function GetName( _ ByVal i As Integer _ ) As String _ _ Implements IDataRecord.GetName *Syntax: C#* public string GetName( inti ); *Parameters* * `i': *Return Value* *Implements* IDataRecord.GetName *See Also* *Note MySqlDataReader Class: connector-net-ref-mysqlclient-mysqldatareader, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqldatareader-getordinal, Next: connector-net-ref-mysqlclient-mysqldatareader-getschematable, Prev: connector-net-ref-mysqlclient-mysqldatareader-getname, Up: connector-net-ref-mysqlclient-mysqldatareadermembers 21.2.7.141 `MySqlDataReader.GetOrdinal' Method .............................................. Gets the column ordinal, given the name of the column. *Syntax: Visual Basic* NotOverridable Public Function GetOrdinal( _ ByVal name As String _ ) As Integer _ _ Implements IDataRecord.GetOrdinal *Syntax: C#* public int GetOrdinal( stringname ); *Parameters* * `name': *Return Value* *Implements* IDataRecord.GetOrdinal *See Also* *Note MySqlDataReader Class: connector-net-ref-mysqlclient-mysqldatareader, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqldatareader-getschematable, Next: connector-net-ref-mysqlclient-mysqldatareader-getstring, Prev: connector-net-ref-mysqlclient-mysqldatareader-getordinal, Up: connector-net-ref-mysqlclient-mysqldatareadermembers 21.2.7.142 `MySqlDataReader.GetSchemaTable' Method .................................................. Returns a DataTable that describes the column metadata of the MySqlDataReader. *Syntax: Visual Basic* NotOverridable Public Function GetSchemaTable() As DataTable _ _ Implements IDataReader.GetSchemaTable *Syntax: C#* public DataTable GetSchemaTable(); *Return Value* *Implements* IDataReader.GetSchemaTable *See Also* *Note MySqlDataReader Class: connector-net-ref-mysqlclient-mysqldatareader, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqldatareader-getstring, Next: connector-net-ref-mysqlclient-mysqldatareader-gettimespan, Prev: connector-net-ref-mysqlclient-mysqldatareader-getschematable, Up: connector-net-ref-mysqlclient-mysqldatareadermembers 21.2.7.143 `MySqlDataReader.GetString' Method ............................................. *Syntax: Visual Basic* NotOverridable Public Function GetString( _ ByVal index As Integer _ ) As String _ _ Implements IDataRecord.GetString *Syntax: C#* public string GetString( intindex ); *Implements* IDataRecord.GetString *See Also* *Note MySqlDataReader Class: connector-net-ref-mysqlclient-mysqldatareader, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqldatareader-gettimespan, Next: connector-net-ref-mysqlclient-mysqldatareader-getuint16, Prev: connector-net-ref-mysqlclient-mysqldatareader-getstring, Up: connector-net-ref-mysqlclient-mysqldatareadermembers 21.2.7.144 `MySqlDataReader.GetTimeSpan' Method ............................................... *Syntax: Visual Basic* Public Function GetTimeSpan( _ ByVal index As Integer _ ) As TimeSpan *Syntax: C#* public TimeSpan GetTimeSpan( intindex ); *See Also* *Note MySqlDataReader Class: connector-net-ref-mysqlclient-mysqldatareader, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqldatareader-getuint16, Next: connector-net-ref-mysqlclient-mysqldatareader-getuint32, Prev: connector-net-ref-mysqlclient-mysqldatareader-gettimespan, Up: connector-net-ref-mysqlclient-mysqldatareadermembers 21.2.7.145 `MySqlDataReader.GetUInt16' Method ............................................. *Syntax: Visual Basic* Public Function GetUInt16( _ ByVal index As Integer _ ) As UInt16 *Syntax: C#* public ushort GetUInt16( intindex ); *See Also* *Note MySqlDataReader Class: connector-net-ref-mysqlclient-mysqldatareader, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqldatareader-getuint32, Next: connector-net-ref-mysqlclient-mysqldatareader-getuint64, Prev: connector-net-ref-mysqlclient-mysqldatareader-getuint16, Up: connector-net-ref-mysqlclient-mysqldatareadermembers 21.2.7.146 `MySqlDataReader.GetUInt32' Method ............................................. *Syntax: Visual Basic* Public Function GetUInt32( _ ByVal index As Integer _ ) As UInt32 *Syntax: C#* public uint GetUInt32( intindex ); *See Also* *Note MySqlDataReader Class: connector-net-ref-mysqlclient-mysqldatareader, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqldatareader-getuint64, Next: connector-net-ref-mysqlclient-mysqldatareader-getvalue, Prev: connector-net-ref-mysqlclient-mysqldatareader-getuint32, Up: connector-net-ref-mysqlclient-mysqldatareadermembers 21.2.7.147 `MySqlDataReader.GetUInt64' Method ............................................. *Syntax: Visual Basic* Public Function GetUInt64( _ ByVal index As Integer _ ) As UInt64 *Syntax: C#* public ulong GetUInt64( intindex ); *See Also* *Note MySqlDataReader Class: connector-net-ref-mysqlclient-mysqldatareader, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqldatareader-getvalue, Next: connector-net-ref-mysqlclient-mysqldatareader-getvalues, Prev: connector-net-ref-mysqlclient-mysqldatareader-getuint64, Up: connector-net-ref-mysqlclient-mysqldatareadermembers 21.2.7.148 `MySqlDataReader.GetValue' Method ............................................ Gets the value of the specified column in its native format. *Syntax: Visual Basic* NotOverridable Public Function GetValue( _ ByVal i As Integer _ ) As Object _ _ Implements IDataRecord.GetValue *Syntax: C#* public object GetValue( inti ); *Parameters* * `i': *Return Value* *Implements* IDataRecord.GetValue *See Also* *Note MySqlDataReader Class: connector-net-ref-mysqlclient-mysqldatareader, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqldatareader-getvalues, Next: connector-net-ref-mysqlclient-mysqldatareader-isdbnull, Prev: connector-net-ref-mysqlclient-mysqldatareader-getvalue, Up: connector-net-ref-mysqlclient-mysqldatareadermembers 21.2.7.149 `MySqlDataReader.GetValues' Method ............................................. Gets all attribute columns in the collection for the current row. *Syntax: Visual Basic* NotOverridable Public Function GetValues( _ ByVal values As Object() _ ) As Integer _ _ Implements IDataRecord.GetValues *Syntax: C#* public int GetValues( object[]values ); *Parameters* * `values': *Return Value* *Implements* IDataRecord.GetValues *See Also* *Note MySqlDataReader Class: connector-net-ref-mysqlclient-mysqldatareader, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqldatareader-isdbnull, Next: connector-net-ref-mysqlclient-mysqldatareader-nextresult, Prev: connector-net-ref-mysqlclient-mysqldatareader-getvalues, Up: connector-net-ref-mysqlclient-mysqldatareadermembers 21.2.7.150 `MySqlDataReader.IsDBNull' Method ............................................ Gets a value indicating whether the column contains non-existent or missing values. *Syntax: Visual Basic* NotOverridable Public Function IsDBNull( _ ByVal i As Integer _ ) As Boolean _ _ Implements IDataRecord.IsDBNull *Syntax: C#* public bool IsDBNull( inti ); *Parameters* * `i': *Return Value* *Implements* IDataRecord.IsDBNull *See Also* *Note MySqlDataReader Class: connector-net-ref-mysqlclient-mysqldatareader, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqldatareader-nextresult, Next: connector-net-ref-mysqlclient-mysqldatareader-read, Prev: connector-net-ref-mysqlclient-mysqldatareader-isdbnull, Up: connector-net-ref-mysqlclient-mysqldatareadermembers 21.2.7.151 `MySqlDataReader.NextResult' Method .............................................. Advances the data reader to the next result, when reading the results of batch SQL statements. *Syntax: Visual Basic* NotOverridable Public Function NextResult() As Boolean _ _ Implements IDataReader.NextResult *Syntax: C#* public bool NextResult(); *Return Value* *Implements* IDataReader.NextResult *See Also* *Note MySqlDataReader Class: connector-net-ref-mysqlclient-mysqldatareader, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqldatareader-read, Prev: connector-net-ref-mysqlclient-mysqldatareader-nextresult, Up: connector-net-ref-mysqlclient-mysqldatareadermembers 21.2.7.152 `MySqlDataReader.Read' Method ........................................ Advances the MySqlDataReader to the next record. *Syntax: Visual Basic* NotOverridable Public Function Read() As Boolean _ _ Implements IDataReader.Read *Syntax: C#* public bool Read(); *Return Value* *Implements* IDataReader.Read *See Also* *Note MySqlDataReader Class: connector-net-ref-mysqlclient-mysqldatareader, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlcommand-executereader-overload-2, Prev: connector-net-ref-mysqlclient-mysqlcommand-executereader-overload-1, Up: connector-net-ref-mysqlclient-mysqlcommand-executereader-overloads 21.2.7.153 `MySqlCommand.ExecuteReader' Method .............................................. *Syntax: Visual Basic* Overloads Public Function ExecuteReader( _ ByVal behavior As CommandBehavior _ ) As MySqlDataReader *Syntax: C#* public MySqlDataReader ExecuteReader( CommandBehaviorbehavior ); *See Also* *Note MySqlCommand Class: connector-net-ref-mysqlclient-mysqlcommand, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note MySqlCommand.ExecuteReader Overload List: connector-net-ref-mysqlclient-mysqlcommand-executereader-overloads.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlcommand-executescalar, Next: connector-net-ref-mysqlclient-mysqlcommand-prepare, Prev: connector-net-ref-mysqlclient-mysqlcommand-executereader-overloads, Up: connector-net-ref-mysqlclient-mysqlcommandmembers 21.2.7.154 `MySqlCommand.ExecuteScalar' Method .............................................. *Syntax: Visual Basic* NotOverridable Public Function ExecuteScalar() As Object _ _ Implements IDbCommand.ExecuteScalar *Syntax: C#* public object ExecuteScalar(); *Implements* IDbCommand.ExecuteScalar *See Also* *Note MySqlCommand Class: connector-net-ref-mysqlclient-mysqlcommand, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlcommand-prepare, Prev: connector-net-ref-mysqlclient-mysqlcommand-executescalar, Up: connector-net-ref-mysqlclient-mysqlcommandmembers 21.2.7.155 `MySqlCommand.Prepare' Method ........................................ *Syntax: Visual Basic* NotOverridable Public Sub Prepare() _ _ Implements IDbCommand.Prepare *Syntax: C#* public void Prepare(); *Implements* IDbCommand.Prepare *See Also* *Note MySqlCommand Class: connector-net-ref-mysqlclient-mysqlcommand, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlcommandbuilder, Next: connector-net-ref-mysqlclient-mysqlexception, Prev: connector-net-ref-mysqlclient-mysqlcommand, Up: connector-net-ref-mysqlclient 21.2.7.156 `MySqlCommandBuilder' Class ...................................... * Menu: * connector-net-ref-mysqlclient-mysqlcommandbuildermembers:: `MySqlCommandBuilder' Members For a list of all members of this type, see *Note MySqlCommandBuilder Members: connector-net-ref-mysqlclient-mysqlcommandbuildermembers . *Syntax: Visual Basic* NotInheritable Public Class MySqlCommandBuilder_ Inherits Component *Syntax: C#* public sealed class MySqlCommandBuilder : Component *Thread Safety* Public static (Sharedin Visual Basic) members of this type are safe for multithreaded operations. Instance members are notguaranteed to be thread-safe. *Requirements* Namespace: *Note MySql.Data.MySqlClient: connector-net-ref-mysqlclient. Assembly: MySql.Data (in MySql.Data.dll) *See Also* *Note MySqlCommandBuilder Members: connector-net-ref-mysqlclient-mysqlcommandbuildermembers, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlcommandbuildermembers, Prev: connector-net-ref-mysqlclient-mysqlcommandbuilder, Up: connector-net-ref-mysqlclient-mysqlcommandbuilder 21.2.7.157 `MySqlCommandBuilder' Members ........................................ * Menu: * connector-net-ref-mysqlclient-mysqlcommandbuilder-deriveparameters-overloads:: DeriveParameters Method * connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor:: `MySqlCommandBuilder' Constructor * connector-net-ref-mysqlclient-mysqlcommandbuilder-dataadapter:: DataAdapter Property * connector-net-ref-mysqlclient-mysqlcommandbuilder-quoteprefix:: QuotePrefix Property * connector-net-ref-mysqlclient-mysqlcommandbuilder-quotesuffix:: QuoteSuffix Property * connector-net-ref-mysqlclient-mysqlcommandbuilder-getdeletecommand:: `MySqlCommandBuilder.GetDeleteCommand' Method * connector-net-ref-mysqlclient-mysqlcommandbuilder-getinsertcommand:: `MySqlCommandBuilder.GetInsertCommand' Method * connector-net-ref-mysqlclient-mysqlcommandbuilder-getupdatecommand:: `MySqlCommandBuilder.GetUpdateCommand' Method * connector-net-ref-mysqlclient-mysqlcommandbuilder-refreshschema:: `MySqlCommandBuilder.RefreshSchema' Method *Note MySqlCommandBuilder overview: connector-net-ref-mysqlclient-mysqlcommandbuilder. *Public Static (Shared) Methods* *Note DeriveParameters: Overloaded. Retrieves parameter connector-net-ref-mysqlclient-mysqlcommandbuilder-deriveparameters-overloads.information from the stored procedure specified in the MySqlCommand and populates the Parameters collection of the specified MySqlCommand object. This method is not currently supported since stored procedures are not available in MySql. *Public Instance Constructors* *Note MySqlCommandBuilder: Overloaded. Initializes a new connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor.instance of the MySqlCommandBuilder class. *Public Instance Properties* Container(inherited from Component) Gets the IContainerthat contains the Component. *Note DataAdapter: connector-net-ref-mysqlclient-mysqlcommandbuilder-dataadapter. *Note QuotePrefix: connector-net-ref-mysqlclient-mysqlcommandbuilder-quoteprefix. *Note QuoteSuffix: connector-net-ref-mysqlclient-mysqlcommandbuilder-quotesuffix. Site(inherited from Component) Gets or sets the ISiteof the Component. *Public Instance Methods* CreateObjRef(inherited from Creates an object that contains all MarshalByRefObject) the relevant information required to generate a proxy used to communicate with a remote object. Dispose(inherited from Component) Releases all resources used by the Component. Equals(inherited from Object) Determines whether the specified Objectis equal to the current Object. *Note GetDeleteCommand: connector-net-ref-mysqlclient-mysqlcommandbuilder-getdeletecommand. GetHashCode(inherited from Object) Serves as a hash function for a particular type. GetHashCodeis suitable for use in hashing algorithms and data structures like a hash table. *Note GetInsertCommand: connector-net-ref-mysqlclient-mysqlcommandbuilder-getinsertcommand. GetLifetimeService(inherited from Retrieves the current lifetime MarshalByRefObject) service object that controls the lifetime policy for this instance. GetType(inherited from Object) Gets the Typeof the current instance. *Note GetUpdateCommand: connector-net-ref-mysqlclient-mysqlcommandbuilder-getupdatecommand. InitializeLifetimeService(inherited Obtains a lifetime service object from MarshalByRefObject) to control the lifetime policy for this instance. *Note RefreshSchema: connector-net-ref-mysqlclient-mysqlcommandbuilder-refreshschema. ToString(inherited from Component) Returns a Stringcontaining the name of the Component, if any. This method should not be overridden. *Public Instance Events* Disposed(inherited from Component) Adds an event handler to listen to the Disposedevent on the component. *See Also* *Note MySqlCommandBuilder Class: connector-net-ref-mysqlclient-mysqlcommandbuilder, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlcommandbuilder-deriveparameters-overloads, Next: connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor, Prev: connector-net-ref-mysqlclient-mysqlcommandbuildermembers, Up: connector-net-ref-mysqlclient-mysqlcommandbuildermembers 21.2.7.158 DeriveParameters Method .................................. * Menu: * connector-net-ref-mysqlclient-mysqlcommandbuilder-deriveparameters-overload-1:: `MySqlCommandBuilder.DeriveParameters' Method * connector-net-ref-mysqlclient-mysqlcommandbuilder-deriveparameters-overload-2:: `MySqlCommandBuilder.DeriveParameters' Method Retrieves parameter information from the stored procedure specified in the MySqlCommand and populates the Parameters collection of the specified MySqlCommand object. This method is not currently supported since stored procedures are not available in MySql. *Overload List* Retrieves parameter information from the stored procedure specified in the MySqlCommand and populates the Parameters collection of the specified MySqlCommand object. This method is not currently supported since stored procedures are not available in MySql. * *Note public static void DeriveParameters(MySqlCommand);: connector-net-ref-mysqlclient-mysqlcommandbuilder-deriveparameters-overload-1. * *Note public static void DeriveParameters(MySqlCommand: (bool);)connector-net-ref-mysqlclient-mysqlcommandbuilder-deriveparameters-overload-2. *See Also* *Note MySqlCommandBuilder Class: connector-net-ref-mysqlclient-mysqlcommandbuilder, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlcommandbuilder-deriveparameters-overload-1, Next: connector-net-ref-mysqlclient-mysqlcommandbuilder-deriveparameters-overload-2, Prev: connector-net-ref-mysqlclient-mysqlcommandbuilder-deriveparameters-overloads, Up: connector-net-ref-mysqlclient-mysqlcommandbuilder-deriveparameters-overloads 21.2.7.159 `MySqlCommandBuilder.DeriveParameters' Method ........................................................ Retrieves parameter information from the stored procedure specified in the MySqlCommand and populates the Parameters collection of the specified MySqlCommand object. This method is not currently supported since stored procedures are not available in MySql. *Syntax: Visual Basic* Overloads Public Shared Sub DeriveParameters( _ ByVal command As MySqlCommand _ ) *Syntax: C#* public static void DeriveParameters( MySqlCommandcommand ); *Parameters* * `command': The MySqlCommand referencing the stored procedure from which the parameter information is to be derived. The derived parameters are added to the Parameters collection of the MySqlCommand. *Exceptions* *Exception Type* *Condition* InvalidOperationException The command text is not a valid stored procedure name. *See Also* *Note MySqlCommandBuilder Class: connector-net-ref-mysqlclient-mysqlcommandbuilder, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note MySqlCommandBuilder.DeriveParameters Overload List: connector-net-ref-mysqlclient-mysqlcommandbuilder-deriveparameters-overloads.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlcommandbuilder-deriveparameters-overload-2, Prev: connector-net-ref-mysqlclient-mysqlcommandbuilder-deriveparameters-overload-1, Up: connector-net-ref-mysqlclient-mysqlcommandbuilder-deriveparameters-overloads 21.2.7.160 `MySqlCommandBuilder.DeriveParameters' Method ........................................................ *Syntax: Visual Basic* Overloads Public Shared Sub DeriveParameters( _ ByVal command As MySqlCommand, _ ByVal useProc As Boolean _ ) *Syntax: C#* public static void DeriveParameters( MySqlCommandcommand, booluseProc ); *See Also* *Note MySqlCommandBuilder Class: connector-net-ref-mysqlclient-mysqlcommandbuilder, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note MySqlCommandBuilder.DeriveParameters Overload List: connector-net-ref-mysqlclient-mysqlcommandbuilder-deriveparameters-overloads.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor, Next: connector-net-ref-mysqlclient-mysqlcommandbuilder-dataadapter, Prev: connector-net-ref-mysqlclient-mysqlcommandbuilder-deriveparameters-overloads, Up: connector-net-ref-mysqlclient-mysqlcommandbuildermembers 21.2.7.161 `MySqlCommandBuilder' Constructor ............................................ * Menu: * connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor1:: `MySqlCommandBuilder' Constructor * connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor3:: `MySqlCommandBuilder' Constructor * connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor4:: `MySqlCommandBuilder' Constructor * connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor2:: `MySqlCommandBuilder' Constructor Initializes a new instance of the *Note MySqlCommandBuilder: connector-net-ref-mysqlclient-mysqlcommandbuilder. class. *Overload List* Initializes a new instance of the *Note MySqlCommandBuilder: connector-net-ref-mysqlclient-mysqlcommandbuilder. class. * *Note public MySqlCommandBuilder();: connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor1. * *Note public MySqlCommandBuilder(MySqlDataAdapter);: connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor3. * *Note public MySqlCommandBuilder(MySqlDataAdapter: (bool);)connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor4. * *Note public MySqlCommandBuilder(bool);: connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor2. *See Also* *Note MySqlCommandBuilder Class: connector-net-ref-mysqlclient-mysqlcommandbuilder, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor1, Next: connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor3, Prev: connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor, Up: connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor 21.2.7.162 `MySqlCommandBuilder' Constructor ............................................ Initializes a new instance of the *Note MySqlCommandBuilder: connector-net-ref-mysqlclient-mysqlcommandbuilder. class. *Syntax: Visual Basic* Overloads Public Sub New() *Syntax: C#* public MySqlCommandBuilder(); *See Also* *Note MySqlCommandBuilder Class: connector-net-ref-mysqlclient-mysqlcommandbuilder, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note MySqlCommandBuilder Constructor Overload List: connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor3, Next: connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor4, Prev: connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor1, Up: connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor 21.2.7.163 `MySqlCommandBuilder' Constructor ............................................ * Menu: * connector-net-ref-mysqlclient-mysqldataadapter:: `MySqlDataAdapter' Class *Syntax: Visual Basic* Overloads Public Sub New( _ ByVal adapter As MySqlDataAdapter _ ) *Syntax: C#* public MySqlCommandBuilder( MySqlDataAdapteradapter ); *See Also* *Note MySqlCommandBuilder Class: connector-net-ref-mysqlclient-mysqlcommandbuilder, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note MySqlCommandBuilder Constructor Overload List: connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqldataadapter, Prev: connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor3, Up: connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor3 21.2.7.164 `MySqlDataAdapter' Class ................................... * Menu: * connector-net-ref-mysqlclient-mysqldataadaptermembers:: `MySqlDataAdapter' Members For a list of all members of this type, see *Note MySqlDataAdapter Members: connector-net-ref-mysqlclient-mysqldataadaptermembers . *Syntax: Visual Basic* NotInheritable Public Class MySqlDataAdapter_ Inherits DbDataAdapter *Syntax: C#* public sealed class MySqlDataAdapter : DbDataAdapter *Thread Safety* Public static (Sharedin Visual Basic) members of this type are safe for multithreaded operations. Instance members are notguaranteed to be thread-safe. *Requirements* Namespace: *Note MySql.Data.MySqlClient: connector-net-ref-mysqlclient. Assembly: MySql.Data (in MySql.Data.dll) *See Also* *Note MySqlDataAdapter Members: connector-net-ref-mysqlclient-mysqldataadaptermembers, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqldataadaptermembers, Prev: connector-net-ref-mysqlclient-mysqldataadapter, Up: connector-net-ref-mysqlclient-mysqldataadapter 21.2.7.165 `MySqlDataAdapter' Members ..................................... * Menu: * connector-net-ref-mysqlclient-mysqldataadapterconstructor:: `MySqlDataAdapter' Constructor * connector-net-ref-mysqlclient-mysqldataadapter-deletecommand1:: DeleteCommand Property * connector-net-ref-mysqlclient-mysqldataadapter-insertcommand1:: InsertCommand Property * connector-net-ref-mysqlclient-mysqldataadapter-selectcommand1:: SelectCommand Property * connector-net-ref-mysqlclient-mysqldataadapter-updatecommand1:: UpdateCommand Property * connector-net-ref-mysqlclient-mysqldataadapter-rowupdated:: `MySqlDataAdapter.RowUpdated' Event * connector-net-ref-mysqlclient-mysqldataadapter-rowupdating:: `MySqlDataAdapter.RowUpdating' Event *Note MySqlDataAdapter overview: connector-net-ref-mysqlclient-mysqldataadapter. *Public Instance Constructors* *Note MySqlDataAdapter: Overloaded. Initializes a new connector-net-ref-mysqlclient-mysqldataadapterconstructor.instance of the MySqlDataAdapter class. *Public Instance Properties* AcceptChangesDuringFill(inherited Gets or sets a value indicating from DataAdapter) whether AcceptChangesis called on a DataRowafter it is added to the DataTableduring any of the Fill operations. AcceptChangesDuringUpdate(inherited Gets or sets whether from DataAdapter) AcceptChangesis called during a Update. Container(inherited from Component) Gets the IContainerthat contains the Component. ContinueUpdateOnError(inherited Gets or sets a value that specifies from DataAdapter) whether to generate an exception when an error is encountered during a row update. *Note DeleteCommand: Overloaded. connector-net-ref-mysqlclient-mysqldataadapter-deletecommand1. FillLoadOption(inherited from Gets or sets the LoadOptionthat DataAdapter) determines how the adapter fills the DataTablefrom the DbDataReader. *Note InsertCommand: Overloaded. connector-net-ref-mysqlclient-mysqldataadapter-insertcommand1. MissingMappingAction(inherited from Determines the action to take when DataAdapter) incoming data does not have a matching table or column. MissingSchemaAction(inherited from Determines the action to take when DataAdapter) existing DataSetschema does not match incoming data. ReturnProviderSpecificTypes(inheritedGets or sets whether the Fillmethod from DataAdapter) should return provider-specific values or common CLS-compliant values. *Note SelectCommand: Overloaded. connector-net-ref-mysqlclient-mysqldataadapter-selectcommand1. Site(inherited from Component) Gets or sets the ISiteof the Component. TableMappings(inherited from Gets a collection that provides the DataAdapter) master mapping between a source table and a DataTable. UpdateBatchSize(inherited from Gets or sets a value that enables DbDataAdapter) or disables batch processing support, and specifies the number of commands that can be executed in a batch. *Note UpdateCommand: Overloaded. connector-net-ref-mysqlclient-mysqldataadapter-updatecommand1. *Public Instance Methods* CreateObjRef(inherited from Creates an object that contains all MarshalByRefObject) the relevant information required to generate a proxy used to communicate with a remote object. Dispose(inherited from Component) Releases all resources used by the Component. Equals(inherited from Object) Determines whether the specified Objectis equal to the current Object. Fill(inherited from DbDataAdapter) Overloaded. Adds or refreshes rows in the DataSetto match those in the data source using the DataSetname, and creates a DataTablenamed "Table." FillSchema(inherited from Overloaded. Configures the schema DbDataAdapter) of the specified DataTablebased on the specified SchemaType. GetFillParameters(inherited from Gets the parameters set by the user DbDataAdapter) when executing an SQL *Note `SELECT': select. statement. GetHashCode(inherited from Object) Serves as a hash function for a particular type. GetHashCodeis suitable for use in hashing algorithms and data structures like a hash table. GetLifetimeService(inherited from Retrieves the current lifetime MarshalByRefObject) service object that controls the lifetime policy for this instance. GetType(inherited from Object) Gets the Typeof the current instance. InitializeLifetimeService(inherited Obtains a lifetime service object from MarshalByRefObject) to control the lifetime policy for this instance. ResetFillLoadOption(inherited from Resets FillLoadOptionto its default DataAdapter) state and causes Fillto honor AcceptChangesDuringFill. ShouldSerializeAcceptChangesDuringFill(inheritedDetermines whether the from DataAdapter) AcceptChangesDuringFillproperty should be persisted. ShouldSerializeFillLoadOption(inheritedDetermines whether the from DataAdapter) FillLoadOptionproperty should be persisted. ToString(inherited from Component) Returns a Stringcontaining the name of the Component, if any. This method should not be overridden. Update(inherited from DbDataAdapter) Overloaded. Calls the respective INSERT, UPDATE, or DELETE statements for each inserted, updated, or deleted row in the specified DataSet. *Public Instance Events* Disposed(inherited from Component) Adds an event handler to listen to the Disposedevent on the component. FillError(inherited from Returned when an error occurs DataAdapter) during a fill operation. *Note RowUpdated: Occurs during Update after a connector-net-ref-mysqlclient-mysqldataadapter-rowupdated.command is executed against the data source. The attempt to update is made, so the event fires. *Note RowUpdating: Occurs during Update before a connector-net-ref-mysqlclient-mysqldataadapter-rowupdating.command is executed against the data source. The attempt to update is made, so the event fires. *Protected Internal Instance Properties* FillCommandBehavior(inherited from Gets or sets the behavior of the DbDataAdapter) command used to fill the data adapter. *See Also* *Note MySqlDataAdapter Class: connector-net-ref-mysqlclient-mysqldataadapter, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqldataadapterconstructor, Next: connector-net-ref-mysqlclient-mysqldataadapter-deletecommand1, Prev: connector-net-ref-mysqlclient-mysqldataadaptermembers, Up: connector-net-ref-mysqlclient-mysqldataadaptermembers 21.2.7.166 `MySqlDataAdapter' Constructor ......................................... * Menu: * connector-net-ref-mysqlclient-mysqldataadapterconstructor1:: `MySqlDataAdapter' Constructor * connector-net-ref-mysqlclient-mysqldataadapterconstructor2:: `MySqlDataAdapter' Constructor * connector-net-ref-mysqlclient-mysqldataadapterconstructor3:: `MySqlDataAdapter' Constructor * connector-net-ref-mysqlclient-mysqldataadapterconstructor4:: `MySqlDataAdapter' Constructor Initializes a new instance of the *Note MySqlDataAdapter: connector-net-ref-mysqlclient-mysqldataadapter. class. *Overload List* Initializes a new instance of the *Note MySqlDataAdapter: connector-net-ref-mysqlclient-mysqldataadapter. class. * *Note public MySqlDataAdapter();: connector-net-ref-mysqlclient-mysqldataadapterconstructor1. * *Note public MySqlDataAdapter(MySqlCommand);: connector-net-ref-mysqlclient-mysqldataadapterconstructor2. * *Note public MySqlDataAdapter(string: (MySqlConnection);)connector-net-ref-mysqlclient-mysqldataadapterconstructor3. * *Note public MySqlDataAdapter(string: (string);)connector-net-ref-mysqlclient-mysqldataadapterconstructor4. *See Also* *Note MySqlDataAdapter Class: connector-net-ref-mysqlclient-mysqldataadapter, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqldataadapterconstructor1, Next: connector-net-ref-mysqlclient-mysqldataadapterconstructor2, Prev: connector-net-ref-mysqlclient-mysqldataadapterconstructor, Up: connector-net-ref-mysqlclient-mysqldataadapterconstructor 21.2.7.167 `MySqlDataAdapter' Constructor ......................................... Initializes a new instance of the *Note MySqlDataAdapter: connector-net-ref-mysqlclient-mysqldataadapter. class. *Syntax: Visual Basic* Overloads Public Sub New() *Syntax: C#* public MySqlDataAdapter(); *See Also* *Note MySqlDataAdapter Class: connector-net-ref-mysqlclient-mysqldataadapter, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note MySqlDataAdapter Constructor Overload List: connector-net-ref-mysqlclient-mysqldataadapterconstructor.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqldataadapterconstructor2, Next: connector-net-ref-mysqlclient-mysqldataadapterconstructor3, Prev: connector-net-ref-mysqlclient-mysqldataadapterconstructor1, Up: connector-net-ref-mysqlclient-mysqldataadapterconstructor 21.2.7.168 `MySqlDataAdapter' Constructor ......................................... *Syntax: Visual Basic* Overloads Public Sub New( _ ByVal selectCommand As MySqlCommand _ ) *Syntax: C#* public MySqlDataAdapter( MySqlCommandselectCommand ); *See Also* *Note MySqlDataAdapter Class: connector-net-ref-mysqlclient-mysqldataadapter, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note MySqlDataAdapter Constructor Overload List: connector-net-ref-mysqlclient-mysqldataadapterconstructor.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqldataadapterconstructor3, Next: connector-net-ref-mysqlclient-mysqldataadapterconstructor4, Prev: connector-net-ref-mysqlclient-mysqldataadapterconstructor2, Up: connector-net-ref-mysqlclient-mysqldataadapterconstructor 21.2.7.169 `MySqlDataAdapter' Constructor ......................................... *Syntax: Visual Basic* Overloads Public Sub New( _ ByVal selectCommandText As String, _ ByVal connection As MySqlConnection _ ) *Syntax: C#* public MySqlDataAdapter( stringselectCommandText, MySqlConnectionconnection ); *See Also* *Note MySqlDataAdapter Class: connector-net-ref-mysqlclient-mysqldataadapter, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note MySqlDataAdapter Constructor Overload List: connector-net-ref-mysqlclient-mysqldataadapterconstructor.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqldataadapterconstructor4, Prev: connector-net-ref-mysqlclient-mysqldataadapterconstructor3, Up: connector-net-ref-mysqlclient-mysqldataadapterconstructor 21.2.7.170 `MySqlDataAdapter' Constructor ......................................... *Syntax: Visual Basic* Overloads Public Sub New( _ ByVal selectCommandText As String, _ ByVal selectConnString As String _ ) *Syntax: C#* public MySqlDataAdapter( stringselectCommandText, stringselectConnString ); *See Also* *Note MySqlDataAdapter Class: connector-net-ref-mysqlclient-mysqldataadapter, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note MySqlDataAdapter Constructor Overload List: connector-net-ref-mysqlclient-mysqldataadapterconstructor.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqldataadapter-deletecommand1, Next: connector-net-ref-mysqlclient-mysqldataadapter-insertcommand1, Prev: connector-net-ref-mysqlclient-mysqldataadapterconstructor, Up: connector-net-ref-mysqlclient-mysqldataadaptermembers 21.2.7.171 DeleteCommand Property ................................. *Syntax: Visual Basic* Overloads Public Property DeleteCommand As MySqlCommand *Syntax: C#* new public MySqlCommand DeleteCommand {get; set;} *See Also* *Note MySqlDataAdapter Class: connector-net-ref-mysqlclient-mysqldataadapter, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqldataadapter-insertcommand1, Next: connector-net-ref-mysqlclient-mysqldataadapter-selectcommand1, Prev: connector-net-ref-mysqlclient-mysqldataadapter-deletecommand1, Up: connector-net-ref-mysqlclient-mysqldataadaptermembers 21.2.7.172 InsertCommand Property ................................. *Syntax: Visual Basic* Overloads Public Property InsertCommand As MySqlCommand *Syntax: C#* new public MySqlCommand InsertCommand {get; set;} *See Also* *Note MySqlDataAdapter Class: connector-net-ref-mysqlclient-mysqldataadapter, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqldataadapter-selectcommand1, Next: connector-net-ref-mysqlclient-mysqldataadapter-updatecommand1, Prev: connector-net-ref-mysqlclient-mysqldataadapter-insertcommand1, Up: connector-net-ref-mysqlclient-mysqldataadaptermembers 21.2.7.173 SelectCommand Property ................................. *Syntax: Visual Basic* Overloads Public Property SelectCommand As MySqlCommand *Syntax: C#* new public MySqlCommand SelectCommand {get; set;} *See Also* *Note MySqlDataAdapter Class: connector-net-ref-mysqlclient-mysqldataadapter, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqldataadapter-updatecommand1, Next: connector-net-ref-mysqlclient-mysqldataadapter-rowupdated, Prev: connector-net-ref-mysqlclient-mysqldataadapter-selectcommand1, Up: connector-net-ref-mysqlclient-mysqldataadaptermembers 21.2.7.174 UpdateCommand Property ................................. *Syntax: Visual Basic* Overloads Public Property UpdateCommand As MySqlCommand *Syntax: C#* new public MySqlCommand UpdateCommand {get; set;} *See Also* *Note MySqlDataAdapter Class: connector-net-ref-mysqlclient-mysqldataadapter, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqldataadapter-rowupdated, Next: connector-net-ref-mysqlclient-mysqldataadapter-rowupdating, Prev: connector-net-ref-mysqlclient-mysqldataadapter-updatecommand1, Up: connector-net-ref-mysqlclient-mysqldataadaptermembers 21.2.7.175 `MySqlDataAdapter.RowUpdated' Event .............................................. * Menu: * connector-net-ref-mysqlclient-mysqlrowupdatedeventhandler:: `MySqlRowUpdatedEventHandler' Delegate Occurs during Update after a command is executed against the data source. The attempt to update is made, so the event fires. *Syntax: Visual Basic* Public Event RowUpdated As MySqlRowUpdatedEventHandler *Syntax: C#* public event MySqlRowUpdatedEventHandler RowUpdated; *Event Data* The event handler receives an argument of type *Note MySqlRowUpdatedEventArgs: connector-net-ref-mysqlclient-mysqlrowupdatedeventargs. containing data related to this event. The following MySqlRowUpdatedEventArgsproperties provide information specific to this event. *Property* *Description* *Note Command: Gets or sets the MySqlCommand connector-net-ref-mysqlclient-mysqlrowupdatedeventargs-command1.executed when Update is called. Errors Gets any errors generated by the .NET Framework data provider when the Commandwas executed. RecordsAffected Gets the number of rows changed, inserted, or deleted by execution of the SQL statement. Row Gets the DataRowsent through an Update. RowCount Gets the number of rows processed in a batch of updated records. StatementType Gets the type of SQL statement executed. Status Gets the UpdateStatusof the Commandproperty. TableMapping Gets the DataTableMappingsent through an Update. *See Also* *Note MySqlDataAdapter Class: connector-net-ref-mysqlclient-mysqldataadapter, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlrowupdatedeventhandler, Prev: connector-net-ref-mysqlclient-mysqldataadapter-rowupdated, Up: connector-net-ref-mysqlclient-mysqldataadapter-rowupdated 21.2.7.176 `MySqlRowUpdatedEventHandler' Delegate ................................................. * Menu: * connector-net-ref-mysqlclient-mysqlrowupdatedeventargs:: `MySqlRowUpdatedEventArgs' Class Represents the method that will handle the RowUpdatedevent of a *Note MySqlDataAdapter: connector-net-ref-mysqlclient-mysqldataadapter . *Syntax: Visual Basic* Public Delegate Sub MySqlRowUpdatedEventHandler( _ ByVal sender As Object, _ ByVal e As MySqlRowUpdatedEventArgs _ ) *Syntax: C#* public delegate void MySqlRowUpdatedEventHandler( objectsender, MySqlRowUpdatedEventArgse ); *Requirements* Namespace: *Note MySql.Data.MySqlClient: connector-net-ref-mysqlclient. Assembly: MySql.Data (in MySql.Data.dll) *See Also* *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlrowupdatedeventargs, Prev: connector-net-ref-mysqlclient-mysqlrowupdatedeventhandler, Up: connector-net-ref-mysqlclient-mysqlrowupdatedeventhandler 21.2.7.177 `MySqlRowUpdatedEventArgs' Class ........................................... * Menu: * connector-net-ref-mysqlclient-mysqlrowupdatedeventargsmembers:: `MySqlRowUpdatedEventArgs' Members Provides data for the RowUpdated event. This class cannot be inherited. For a list of all members of this type, see *Note MySqlRowUpdatedEventArgs Members: connector-net-ref-mysqlclient-mysqlrowupdatedeventargsmembers . *Syntax: Visual Basic* NotInheritable Public Class MySqlRowUpdatedEventArgs_ Inherits RowUpdatedEventArgs *Syntax: C#* public sealed class MySqlRowUpdatedEventArgs : RowUpdatedEventArgs *Thread Safety* Public static (Sharedin Visual Basic) members of this type are safe for multithreaded operations. Instance members are notguaranteed to be thread-safe. *Requirements* Namespace: *Note MySql.Data.MySqlClient: connector-net-ref-mysqlclient. Assembly: MySql.Data (in MySql.Data.dll) *See Also* *Note MySqlRowUpdatedEventArgs Members: connector-net-ref-mysqlclient-mysqlrowupdatedeventargsmembers, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlrowupdatedeventargsmembers, Prev: connector-net-ref-mysqlclient-mysqlrowupdatedeventargs, Up: connector-net-ref-mysqlclient-mysqlrowupdatedeventargs 21.2.7.178 `MySqlRowUpdatedEventArgs' Members ............................................. * Menu: * connector-net-ref-mysqlclient-mysqlrowupdatedeventargsconstructor:: `MySqlRowUpdatedEventArgs' Constructor * connector-net-ref-mysqlclient-mysqlrowupdatedeventargs-command1:: Command Property *Note MySqlRowUpdatedEventArgs overview: connector-net-ref-mysqlclient-mysqlrowupdatedeventargs. *Public Instance Constructors* *Note MySqlRowUpdatedEventArgs Initializes a new instance of the Constructor: MySqlRowUpdatedEventArgs class. connector-net-ref-mysqlclient-mysqlrowupdatedeventargsconstructor. *Public Instance Properties* *Note Command: Overloaded. Gets or sets the connector-net-ref-mysqlclient-mysqlrowupdatedeventargs-command1.MySqlCommand executed when Update is called. Errors(inherited from Gets any errors generated by the RowUpdatedEventArgs) .NET Framework data provider when the Commandwas executed. RecordsAffected(inherited from Gets the number of rows changed, RowUpdatedEventArgs) inserted, or deleted by execution of the SQL statement. Row(inherited from Gets the DataRowsent through an RowUpdatedEventArgs) Update. RowCount(inherited from Gets the number of rows processed RowUpdatedEventArgs) in a batch of updated records. StatementType(inherited from Gets the type of SQL statement RowUpdatedEventArgs) executed. Status(inherited from Gets the UpdateStatusof the RowUpdatedEventArgs) Commandproperty. TableMapping(inherited from Gets the DataTableMappingsent RowUpdatedEventArgs) through an Update. *Public Instance Methods* CopyToRows(inherited from Overloaded. Copies references to RowUpdatedEventArgs) the modified rows into the provided array. Equals(inherited from Object) Determines whether the specified Objectis equal to the current Object. GetHashCode(inherited from Object) Serves as a hash function for a particular type. GetHashCodeis suitable for use in hashing algorithms and data structures like a hash table. GetType(inherited from Object) Gets the Typeof the current instance. ToString(inherited from Object) Returns a Stringthat represents the current Object. *See Also* *Note MySqlRowUpdatedEventArgs Class: connector-net-ref-mysqlclient-mysqlrowupdatedeventargs, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlrowupdatedeventargsconstructor, Next: connector-net-ref-mysqlclient-mysqlrowupdatedeventargs-command1, Prev: connector-net-ref-mysqlclient-mysqlrowupdatedeventargsmembers, Up: connector-net-ref-mysqlclient-mysqlrowupdatedeventargsmembers 21.2.7.179 `MySqlRowUpdatedEventArgs' Constructor ................................................. Initializes a new instance of the MySqlRowUpdatedEventArgs class. *Syntax: Visual Basic* Public Sub New( _ ByVal row As DataRow, _ ByVal command As IDbCommand, _ ByVal statementType As StatementType, _ ByVal tableMapping As DataTableMapping _ ) *Syntax: C#* public MySqlRowUpdatedEventArgs( DataRowrow, IDbCommandcommand, StatementTypestatementType, DataTableMappingtableMapping ); *Parameters* * `row': The DataRowsent through an Update. * `command': The IDbCommandexecuted when Updateis called. * `statementType': One of the StatementTypevalues that specifies the type of query executed. * `tableMapping': The DataTableMappingsent through an Update. *See Also* *Note MySqlRowUpdatedEventArgs Class: connector-net-ref-mysqlclient-mysqlrowupdatedeventargs, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlrowupdatedeventargs-command1, Prev: connector-net-ref-mysqlclient-mysqlrowupdatedeventargsconstructor, Up: connector-net-ref-mysqlclient-mysqlrowupdatedeventargsmembers 21.2.7.180 Command Property ........................... Gets or sets the MySqlCommand executed when Update is called. *Syntax: Visual Basic* Overloads Public ReadOnly Property Command As MySqlCommand *Syntax: C#* new public MySqlCommand Command {get;} *See Also* *Note MySqlRowUpdatedEventArgs Class: connector-net-ref-mysqlclient-mysqlrowupdatedeventargs, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqldataadapter-rowupdating, Prev: connector-net-ref-mysqlclient-mysqldataadapter-rowupdated, Up: connector-net-ref-mysqlclient-mysqldataadaptermembers 21.2.7.181 `MySqlDataAdapter.RowUpdating' Event ............................................... * Menu: * connector-net-ref-mysqlclient-mysqlrowupdatingeventhandler:: `MySqlRowUpdatingEventHandler' Delegate Occurs during Update before a command is executed against the data source. The attempt to update is made, so the event fires. *Syntax: Visual Basic* Public Event RowUpdating As MySqlRowUpdatingEventHandler *Syntax: C#* public event MySqlRowUpdatingEventHandler RowUpdating; *Event Data* The event handler receives an argument of type *Note MySqlRowUpdatingEventArgs: connector-net-ref-mysqlclient-mysqlrowupdatingeventargs. containing data related to this event. The following MySqlRowUpdatingEventArgsproperties provide information specific to this event. *Property* *Description* *Note Command: Gets or sets the MySqlCommand to connector-net-ref-mysqlclient-mysqlrowupdatingeventargs-command1.execute when performing the Update. Errors Gets any errors generated by the .NET Framework data provider when the Commandexecutes. Row Gets the DataRowthat will be sent to the server as part of an insert, update, or delete operation. StatementType Gets the type of SQL statement to execute. Status Gets or sets the UpdateStatusof the Commandproperty. TableMapping Gets the DataTableMappingto send through the Update. *See Also* *Note MySqlDataAdapter Class: connector-net-ref-mysqlclient-mysqldataadapter, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlrowupdatingeventhandler, Prev: connector-net-ref-mysqlclient-mysqldataadapter-rowupdating, Up: connector-net-ref-mysqlclient-mysqldataadapter-rowupdating 21.2.7.182 `MySqlRowUpdatingEventHandler' Delegate .................................................. * Menu: * connector-net-ref-mysqlclient-mysqlrowupdatingeventargs:: `MySqlRowUpdatingEventArgs' Class Represents the method that will handle the RowUpdatingevent of a *Note MySqlDataAdapter: connector-net-ref-mysqlclient-mysqldataadapter . *Syntax: Visual Basic* Public Delegate Sub MySqlRowUpdatingEventHandler( _ ByVal sender As Object, _ ByVal e As MySqlRowUpdatingEventArgs _ ) *Syntax: C#* public delegate void MySqlRowUpdatingEventHandler( objectsender, MySqlRowUpdatingEventArgse ); *Requirements* Namespace: *Note MySql.Data.MySqlClient: connector-net-ref-mysqlclient. Assembly: MySql.Data (in MySql.Data.dll) *See Also* *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlrowupdatingeventargs, Prev: connector-net-ref-mysqlclient-mysqlrowupdatingeventhandler, Up: connector-net-ref-mysqlclient-mysqlrowupdatingeventhandler 21.2.7.183 `MySqlRowUpdatingEventArgs' Class ............................................ * Menu: * connector-net-ref-mysqlclient-mysqlrowupdatingeventargsmembers:: `MySqlRowUpdatingEventArgs' Members Provides data for the RowUpdating event. This class cannot be inherited. For a list of all members of this type, see *Note MySqlRowUpdatingEventArgs Members: connector-net-ref-mysqlclient-mysqlrowupdatingeventargsmembers . *Syntax: Visual Basic* NotInheritable Public Class MySqlRowUpdatingEventArgs_ Inherits RowUpdatingEventArgs *Syntax: C#* public sealed class MySqlRowUpdatingEventArgs : RowUpdatingEventArgs *Thread Safety* Public static (Sharedin Visual Basic) members of this type are safe for multithreaded operations. Instance members are notguaranteed to be thread-safe. *Requirements* Namespace: *Note MySql.Data.MySqlClient: connector-net-ref-mysqlclient. Assembly: MySql.Data (in MySql.Data.dll) *See Also* *Note MySqlRowUpdatingEventArgs Members: connector-net-ref-mysqlclient-mysqlrowupdatingeventargsmembers, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlrowupdatingeventargsmembers, Prev: connector-net-ref-mysqlclient-mysqlrowupdatingeventargs, Up: connector-net-ref-mysqlclient-mysqlrowupdatingeventargs 21.2.7.184 `MySqlRowUpdatingEventArgs' Members .............................................. * Menu: * connector-net-ref-mysqlclient-mysqlrowupdatingeventargsconstructor:: `MySqlRowUpdatingEventArgs' Constructor * connector-net-ref-mysqlclient-mysqlrowupdatingeventargs-command1:: Command Property *Note MySqlRowUpdatingEventArgs overview: connector-net-ref-mysqlclient-mysqlrowupdatingeventargs. *Public Instance Constructors* *Note MySqlRowUpdatingEventArgs Initializes a new instance of the Constructor: MySqlRowUpdatingEventArgs class. connector-net-ref-mysqlclient-mysqlrowupdatingeventargsconstructor. *Public Instance Properties* *Note Command: Overloaded. Gets or sets the connector-net-ref-mysqlclient-mysqlrowupdatingeventargs-command1.MySqlCommand to execute when performing the Update. Errors(inherited from Gets any errors generated by the RowUpdatingEventArgs) .NET Framework data provider when the Commandexecutes. Row(inherited from Gets the DataRowthat will be sent RowUpdatingEventArgs) to the server as part of an insert, update, or delete operation. StatementType(inherited from Gets the type of SQL statement to RowUpdatingEventArgs) execute. Status(inherited from Gets or sets the UpdateStatusof the RowUpdatingEventArgs) Commandproperty. TableMapping(inherited from Gets the DataTableMappingto send RowUpdatingEventArgs) through the Update. *Public Instance Methods* Equals(inherited from Object) Determines whether the specified Objectis equal to the current Object. GetHashCode(inherited from Object) Serves as a hash function for a particular type. GetHashCodeis suitable for use in hashing algorithms and data structures like a hash table. GetType(inherited from Object) Gets the Typeof the current instance. ToString(inherited from Object) Returns a Stringthat represents the current Object. *See Also* *Note MySqlRowUpdatingEventArgs Class: connector-net-ref-mysqlclient-mysqlrowupdatingeventargs, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlrowupdatingeventargsconstructor, Next: connector-net-ref-mysqlclient-mysqlrowupdatingeventargs-command1, Prev: connector-net-ref-mysqlclient-mysqlrowupdatingeventargsmembers, Up: connector-net-ref-mysqlclient-mysqlrowupdatingeventargsmembers 21.2.7.185 `MySqlRowUpdatingEventArgs' Constructor .................................................. Initializes a new instance of the MySqlRowUpdatingEventArgs class. *Syntax: Visual Basic* Public Sub New( _ ByVal row As DataRow, _ ByVal command As IDbCommand, _ ByVal statementType As StatementType, _ ByVal tableMapping As DataTableMapping _ ) *Syntax: C#* public MySqlRowUpdatingEventArgs( DataRowrow, IDbCommandcommand, StatementTypestatementType, DataTableMappingtableMapping ); *Parameters* * `row': The DataRowto Update. * `command': The IDbCommandto execute during Update. * `statementType': One of the StatementTypevalues that specifies the type of query executed. * `tableMapping': The DataTableMappingsent through an Update. *See Also* *Note MySqlRowUpdatingEventArgs Class: connector-net-ref-mysqlclient-mysqlrowupdatingeventargs, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlrowupdatingeventargs-command1, Prev: connector-net-ref-mysqlclient-mysqlrowupdatingeventargsconstructor, Up: connector-net-ref-mysqlclient-mysqlrowupdatingeventargsmembers 21.2.7.186 Command Property ........................... Gets or sets the MySqlCommand to execute when performing the Update. *Syntax: Visual Basic* Overloads Public Property Command As MySqlCommand *Syntax: C#* new public MySqlCommand Command {get; set;} *See Also* *Note MySqlRowUpdatingEventArgs Class: connector-net-ref-mysqlclient-mysqlrowupdatingeventargs, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor4, Next: connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor2, Prev: connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor3, Up: connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor 21.2.7.187 `MySqlCommandBuilder' Constructor ............................................ *Syntax: Visual Basic* Overloads Public Sub New( _ ByVal adapter As MySqlDataAdapter, _ ByVal lastOneWins As Boolean _ ) *Syntax: C#* public MySqlCommandBuilder( MySqlDataAdapteradapter, boollastOneWins ); *See Also* *Note MySqlCommandBuilder Class: connector-net-ref-mysqlclient-mysqlcommandbuilder, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note MySqlCommandBuilder Constructor Overload List: connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor2, Prev: connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor4, Up: connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor 21.2.7.188 `MySqlCommandBuilder' Constructor ............................................ *Syntax: Visual Basic* Overloads Public Sub New( _ ByVal lastOneWins As Boolean _ ) *Syntax: C#* public MySqlCommandBuilder( boollastOneWins ); *See Also* *Note MySqlCommandBuilder Class: connector-net-ref-mysqlclient-mysqlcommandbuilder, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note MySqlCommandBuilder Constructor Overload List: connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlcommandbuilder-dataadapter, Next: connector-net-ref-mysqlclient-mysqlcommandbuilder-quoteprefix, Prev: connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor, Up: connector-net-ref-mysqlclient-mysqlcommandbuildermembers 21.2.7.189 DataAdapter Property ............................... *Syntax: Visual Basic* Public Property DataAdapter As MySqlDataAdapter *Syntax: C#* public MySqlDataAdapter DataAdapter {get; set;} *See Also* *Note MySqlCommandBuilder Class: connector-net-ref-mysqlclient-mysqlcommandbuilder, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlcommandbuilder-quoteprefix, Next: connector-net-ref-mysqlclient-mysqlcommandbuilder-quotesuffix, Prev: connector-net-ref-mysqlclient-mysqlcommandbuilder-dataadapter, Up: connector-net-ref-mysqlclient-mysqlcommandbuildermembers 21.2.7.190 QuotePrefix Property ............................... *Syntax: Visual Basic* Public Property QuotePrefix As String *Syntax: C#* public string QuotePrefix {get; set;} *See Also* *Note MySqlCommandBuilder Class: connector-net-ref-mysqlclient-mysqlcommandbuilder, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlcommandbuilder-quotesuffix, Next: connector-net-ref-mysqlclient-mysqlcommandbuilder-getdeletecommand, Prev: connector-net-ref-mysqlclient-mysqlcommandbuilder-quoteprefix, Up: connector-net-ref-mysqlclient-mysqlcommandbuildermembers 21.2.7.191 QuoteSuffix Property ............................... *Syntax: Visual Basic* Public Property QuoteSuffix As String *Syntax: C#* public string QuoteSuffix {get; set;} *See Also* *Note MySqlCommandBuilder Class: connector-net-ref-mysqlclient-mysqlcommandbuilder, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlcommandbuilder-getdeletecommand, Next: connector-net-ref-mysqlclient-mysqlcommandbuilder-getinsertcommand, Prev: connector-net-ref-mysqlclient-mysqlcommandbuilder-quotesuffix, Up: connector-net-ref-mysqlclient-mysqlcommandbuildermembers 21.2.7.192 `MySqlCommandBuilder.GetDeleteCommand' Method ........................................................ *Syntax: Visual Basic* Public Function GetDeleteCommand() As MySqlCommand *Syntax: C#* public MySqlCommand GetDeleteCommand(); *See Also* *Note MySqlCommandBuilder Class: connector-net-ref-mysqlclient-mysqlcommandbuilder, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlcommandbuilder-getinsertcommand, Next: connector-net-ref-mysqlclient-mysqlcommandbuilder-getupdatecommand, Prev: connector-net-ref-mysqlclient-mysqlcommandbuilder-getdeletecommand, Up: connector-net-ref-mysqlclient-mysqlcommandbuildermembers 21.2.7.193 `MySqlCommandBuilder.GetInsertCommand' Method ........................................................ *Syntax: Visual Basic* Public Function GetInsertCommand() As MySqlCommand *Syntax: C#* public MySqlCommand GetInsertCommand(); *See Also* *Note MySqlCommandBuilder Class: connector-net-ref-mysqlclient-mysqlcommandbuilder, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlcommandbuilder-getupdatecommand, Next: connector-net-ref-mysqlclient-mysqlcommandbuilder-refreshschema, Prev: connector-net-ref-mysqlclient-mysqlcommandbuilder-getinsertcommand, Up: connector-net-ref-mysqlclient-mysqlcommandbuildermembers 21.2.7.194 `MySqlCommandBuilder.GetUpdateCommand' Method ........................................................ *Syntax: Visual Basic* Public Function GetUpdateCommand() As MySqlCommand *Syntax: C#* public MySqlCommand GetUpdateCommand(); *See Also* *Note MySqlCommandBuilder Class: connector-net-ref-mysqlclient-mysqlcommandbuilder, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlcommandbuilder-refreshschema, Prev: connector-net-ref-mysqlclient-mysqlcommandbuilder-getupdatecommand, Up: connector-net-ref-mysqlclient-mysqlcommandbuildermembers 21.2.7.195 `MySqlCommandBuilder.RefreshSchema' Method ..................................................... *Syntax: Visual Basic* Public Sub RefreshSchema() *Syntax: C#* public void RefreshSchema(); *See Also* *Note MySqlCommandBuilder Class: connector-net-ref-mysqlclient-mysqlcommandbuilder, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlexception, Next: connector-net-ref-mysqlclient-mysqlhelper, Prev: connector-net-ref-mysqlclient-mysqlcommandbuilder, Up: connector-net-ref-mysqlclient 21.2.7.196 `MySqlException' Class ................................. * Menu: * connector-net-ref-mysqlclient-mysqlexceptionmembers:: `MySqlException' Members The exception that is thrown when MySQL returns an error. This class cannot be inherited. For a list of all members of this type, see *Note MySqlException Members: connector-net-ref-mysqlclient-mysqlexceptionmembers . *Syntax: Visual Basic* NotInheritable Public Class MySqlException_ Inherits SystemException *Syntax: C#* public sealed class MySqlException : SystemException *Thread Safety* Public static (Sharedin Visual Basic) members of this type are safe for multithreaded operations. Instance members are notguaranteed to be thread-safe. *Requirements* Namespace: *Note MySql.Data.MySqlClient: connector-net-ref-mysqlclient. Assembly: MySql.Data (in MySql.Data.dll) *See Also* *Note MySqlException Members: connector-net-ref-mysqlclient-mysqlexceptionmembers, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlexceptionmembers, Prev: connector-net-ref-mysqlclient-mysqlexception, Up: connector-net-ref-mysqlclient-mysqlexception 21.2.7.197 `MySqlException' Members ................................... * Menu: * connector-net-ref-mysqlclient-mysqlexception-number:: Number Property *Note MySqlException overview: connector-net-ref-mysqlclient-mysqlexception. *Public Instance Properties* Data(inherited from Exception) Gets a collection of key/value pairs that provide additional, user-defined information about the exception. HelpLink(inherited from Exception) Gets or sets a link to the help file associated with this exception. InnerException(inherited from Gets the Exceptioninstance that Exception) caused the current exception. Message(inherited from Exception) Gets a message that describes the current exception. *Note Number: Gets a number that identifies the connector-net-ref-mysqlclient-mysqlexception-number.type of error. This number corresponds to the error numbers given in *Note error-messages-server::. Source(inherited from Exception) Gets or sets the name of the application or the object that causes the error. StackTrace(inherited from Exception) Gets a string representation of the frames on the call stack at the time the current exception was thrown. TargetSite(inherited from Exception) Gets the method that throws the current exception. *Public Instance Methods* Equals(inherited from Object) Determines whether the specified Objectis equal to the current Object. GetBaseException(inherited from When overridden in a derived class, Exception) returns the Exceptionthat is the root cause of one or more subsequent exceptions. GetHashCode(inherited from Object) Serves as a hash function for a particular type. GetHashCodeis suitable for use in hashing algorithms and data structures like a hash table. GetObjectData(inherited from When overridden in a derived class, Exception) sets the SerializationInfowith information about the exception. GetType(inherited from Exception) Gets the runtime type of the current instance. ToString(inherited from Exception) Creates and returns a string representation of the current exception. *See Also* *Note MySqlException Class: connector-net-ref-mysqlclient-mysqlexception, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlexception-number, Prev: connector-net-ref-mysqlclient-mysqlexceptionmembers, Up: connector-net-ref-mysqlclient-mysqlexceptionmembers 21.2.7.198 Number Property .......................... Gets a number that identifies the type of error. *Syntax: Visual Basic* Public ReadOnly Property Number As Integer *Syntax: C#* public int Number {get;} *See Also* *Note MySqlException Class: connector-net-ref-mysqlclient-mysqlexception, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlhelper, Next: connector-net-ref-mysqlclient-mysqlerrorcode, Prev: connector-net-ref-mysqlclient-mysqlexception, Up: connector-net-ref-mysqlclient 21.2.7.199 `MySqlHelper' Class .............................. * Menu: * connector-net-ref-mysqlclient-mysqlhelpermembers:: `MySqlHelper' Members Helper class that makes it easier to work with the provider. For a list of all members of this type, see *Note MySqlHelper Members: connector-net-ref-mysqlclient-mysqlhelpermembers . *Syntax: Visual Basic* NotInheritable Public Class MySqlHelper *Syntax: C#* public sealed class MySqlHelper *Thread Safety* Public static (Shared in Visual Basic) members of this type are safe for multithreaded operations. Instance members are not guaranteed to be thread-safe. *Requirements* Namespace: *Note MySql.Data.MySqlClient: connector-net-ref-mysqlclient. Assembly: MySql.Data (in MySql.Data.dll) *See Also* *Note MySqlHelper Members: connector-net-ref-mysqlclient-mysqlhelpermembers, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlhelpermembers, Prev: connector-net-ref-mysqlclient-mysqlhelper, Up: connector-net-ref-mysqlclient-mysqlhelper 21.2.7.200 `MySqlHelper' Members ................................ * Menu: * connector-net-ref-mysqlclient-mysqlhelper-executedatarow:: `MySqlHelper.ExecuteDataRow' Method * connector-net-ref-mysqlclient-mysqlhelper-executedataset-overloads:: ExecuteDataset Method * connector-net-ref-mysqlclient-mysqlhelper-executenonquery-overloads:: ExecuteNonQuery Method * connector-net-ref-mysqlclient-mysqlhelper-executereader-overloads:: ExecuteReader Method * connector-net-ref-mysqlclient-mysqlhelper-executescalar-overloads:: ExecuteScalar Method * connector-net-ref-mysqlclient-mysqlhelper-updatedataset:: `MySqlHelper.UpdateDataSet' Method *Note MySqlHelper overview: connector-net-ref-mysqlclient-mysqlhelper. *Public Static (Shared) Methods* *Note ExecuteDataRow: Executes a single SQL statement and connector-net-ref-mysqlclient-mysqlhelper-executedatarow.returns the first row of the resultset. A new MySqlConnection object is created, opened, and closed during this method. *Note ExecuteDataset: Overloaded. Executes a single SQL connector-net-ref-mysqlclient-mysqlhelper-executedataset-overloads.statement and returns the resultset in a DataSet. A new MySqlConnection object is created, opened, and closed during this method. *Note ExecuteNonQuery: Overloaded. Executes a single connector-net-ref-mysqlclient-mysqlhelper-executenonquery-overloads.command against a MySQL database. The *Note MySqlConnection: connector-net-ref-mysqlclient-mysqlconnection. is assumed to be open when the method is called and remains open after the method completes. *Note ExecuteReader: Overloaded. Executes a single connector-net-ref-mysqlclient-mysqlhelper-executereader-overloads.command against a MySQL database. *Note ExecuteScalar: Overloaded. Execute a single connector-net-ref-mysqlclient-mysqlhelper-executescalar-overloads.command against a MySQL database. *Note UpdateDataSet: Updates the given table with data connector-net-ref-mysqlclient-mysqlhelper-updatedataset.from the given DataSet *Public Instance Methods* Equals(inherited from Object) Determines whether the specified Objectis equal to the current Object. GetHashCode(inherited from Object) Serves as a hash function for a particular type. GetHashCodeis suitable for use in hashing algorithms and data structures like a hash table. GetType(inherited from Object) Gets the Typeof the current instance. ToString(inherited from Object) Returns a Stringthat represents the current Object. *See Also* *Note MySqlHelper Class: connector-net-ref-mysqlclient-mysqlhelper, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlhelper-executedatarow, Next: connector-net-ref-mysqlclient-mysqlhelper-executedataset-overloads, Prev: connector-net-ref-mysqlclient-mysqlhelpermembers, Up: connector-net-ref-mysqlclient-mysqlhelpermembers 21.2.7.201 `MySqlHelper.ExecuteDataRow' Method .............................................. Executes a single SQL statement and returns the first row of the resultset. A new MySqlConnection object is created, opened, and closed during this method. *Syntax: Visual Basic* Public Shared Function ExecuteDataRow( _ ByVal connectionString As String, _ ByVal commandText As String, _ ParamArray parms As MySqlParameter() _ ) As DataRow *Syntax: C#* public static DataRow ExecuteDataRow( stringconnectionString, stringcommandText, params MySqlParameter[]parms ); *Parameters* * `connectionString': Settings to be used for the connection * `commandText': Command to execute * `parms': Parameters to use for the command *Return Value* DataRow containing the first row of the resultset *See Also* *Note MySqlHelper Class: connector-net-ref-mysqlclient-mysqlhelper, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlhelper-executedataset-overloads, Next: connector-net-ref-mysqlclient-mysqlhelper-executenonquery-overloads, Prev: connector-net-ref-mysqlclient-mysqlhelper-executedatarow, Up: connector-net-ref-mysqlclient-mysqlhelpermembers 21.2.7.202 ExecuteDataset Method ................................ * Menu: * connector-net-ref-mysqlclient-mysqlhelper-executedataset-overload-3:: `MySqlHelper.ExecuteDataset' Method * connector-net-ref-mysqlclient-mysqlhelper-executedataset-overload-4:: `MySqlHelper.ExecuteDataset' Method * connector-net-ref-mysqlclient-mysqlhelper-executedataset-overload-1:: `MySqlHelper.ExecuteDataset' Method * connector-net-ref-mysqlclient-mysqlhelper-executedataset-overload-2:: `MySqlHelper.ExecuteDataset' Method Executes a single SQL statement and returns the resultset in a DataSet. The state of the *Note MySqlConnection: connector-net-ref-mysqlclient-mysqlconnection. object remains unchanged after execution of this method. *Overload List* Executes a single SQL statement and returns the resultset in a DataSet. The state of the *Note MySqlConnection: connector-net-ref-mysqlclient-mysqlconnection. object remains unchanged after execution of this method. * *Note public static DataSet ExecuteDataset(MySqlConnection: (string);)connector-net-ref-mysqlclient-mysqlhelper-executedataset-overload-3. Executes a single SQL statement and returns the resultset in a DataSet. The state of the *Note MySqlConnection: connector-net-ref-mysqlclient-mysqlconnection. object remains unchanged after execution of this method. * *Note public static DataSet ExecuteDataset(MySqlConnection: (string)connector-net-ref-mysqlclient-mysqlhelper-executedataset-overload-4. Executes a single SQL statement and returns the resultset in a DataSet. A new MySqlConnection object is created, opened, and closed during this method. * *Note public static DataSet ExecuteDataset(string: (string);)connector-net-ref-mysqlclient-mysqlhelper-executedataset-overload-1. Executes a single SQL statement and returns the resultset in a DataSet. A new MySqlConnection object is created, opened, and closed during this method. * *Note public static DataSet ExecuteDataset(string: (string)connector-net-ref-mysqlclient-mysqlhelper-executedataset-overload-2. *See Also* *Note MySqlHelper Class: connector-net-ref-mysqlclient-mysqlhelper, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlhelper-executedataset-overload-3, Next: connector-net-ref-mysqlclient-mysqlhelper-executedataset-overload-4, Prev: connector-net-ref-mysqlclient-mysqlhelper-executedataset-overloads, Up: connector-net-ref-mysqlclient-mysqlhelper-executedataset-overloads 21.2.7.203 `MySqlHelper.ExecuteDataset' Method .............................................. Executes a single SQL statement and returns the resultset in a DataSet. The state of the *Note MySqlConnection: connector-net-ref-mysqlclient-mysqlconnection. object remains unchanged after execution of this method. *Syntax: Visual Basic* Overloads Public Shared Function ExecuteDataset( _ ByVal connection As MySqlConnection, _ ByVal commandText As String _ ) As DataSet *Syntax: C#* public static DataSet ExecuteDataset( MySqlConnectionconnection, stringcommandText ); *Parameters* * `connection': *Note MySqlConnection: connector-net-ref-mysqlclient-mysqlconnection. object to use * `commandText': Command to execute *Return Value* DataSetcontaining the resultset *See Also* *Note MySqlHelper Class: connector-net-ref-mysqlclient-mysqlhelper, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note MySqlHelper.ExecuteDataset Overload List: connector-net-ref-mysqlclient-mysqlhelper-executedataset-overloads.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlhelper-executedataset-overload-4, Next: connector-net-ref-mysqlclient-mysqlhelper-executedataset-overload-1, Prev: connector-net-ref-mysqlclient-mysqlhelper-executedataset-overload-3, Up: connector-net-ref-mysqlclient-mysqlhelper-executedataset-overloads 21.2.7.204 `MySqlHelper.ExecuteDataset' Method .............................................. Executes a single SQL statement and returns the resultset in a DataSet. The state of the *Note MySqlConnection: connector-net-ref-mysqlclient-mysqlconnection. object remains unchanged after execution of this method. *Syntax: Visual Basic* Overloads Public Shared Function ExecuteDataset( _ ByVal connection As MySqlConnection, _ ByVal commandText As String, _ ParamArray commandParameters As MySqlParameter() _ ) As DataSet *Syntax: C#* public static DataSet ExecuteDataset( MySqlConnectionconnection, stringcommandText, params MySqlParameter[]commandParameters ); *Parameters* * `connection': *Note MySqlConnection: connector-net-ref-mysqlclient-mysqlconnection. object to use * `commandText': Command to execute * `commandParameters': Parameters to use for the command *Return Value* DataSetcontaining the resultset *See Also* *Note MySqlHelper Class: connector-net-ref-mysqlclient-mysqlhelper, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note MySqlHelper.ExecuteDataset Overload List: connector-net-ref-mysqlclient-mysqlhelper-executedataset-overloads.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlhelper-executedataset-overload-1, Next: connector-net-ref-mysqlclient-mysqlhelper-executedataset-overload-2, Prev: connector-net-ref-mysqlclient-mysqlhelper-executedataset-overload-4, Up: connector-net-ref-mysqlclient-mysqlhelper-executedataset-overloads 21.2.7.205 `MySqlHelper.ExecuteDataset' Method .............................................. Executes a single SQL statement and returns the resultset in a DataSet. A new MySqlConnection object is created, opened, and closed during this method. *Syntax: Visual Basic* Overloads Public Shared Function ExecuteDataset( _ ByVal connectionString As String, _ ByVal commandText As String _ ) As DataSet *Syntax: C#* public static DataSet ExecuteDataset( stringconnectionString, stringcommandText ); *Parameters* * `connectionString': Settings to be used for the connection * `commandText': Command to execute *Return Value* DataSetcontaining the resultset *See Also* *Note MySqlHelper Class: connector-net-ref-mysqlclient-mysqlhelper, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note MySqlHelper.ExecuteDataset Overload List: connector-net-ref-mysqlclient-mysqlhelper-executedataset-overloads.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlhelper-executedataset-overload-2, Prev: connector-net-ref-mysqlclient-mysqlhelper-executedataset-overload-1, Up: connector-net-ref-mysqlclient-mysqlhelper-executedataset-overloads 21.2.7.206 `MySqlHelper.ExecuteDataset' Method .............................................. Executes a single SQL statement and returns the resultset in a DataSet. A new MySqlConnection object is created, opened, and closed during this method. *Syntax: Visual Basic* Overloads Public Shared Function ExecuteDataset( _ ByVal connectionString As String, _ ByVal commandText As String, _ ParamArray commandParameters As MySqlParameter() _ ) As DataSet *Syntax: C#* public static DataSet ExecuteDataset( stringconnectionString, stringcommandText, params MySqlParameter[]commandParameters ); *Parameters* * `connectionString': Settings to be used for the connection * `commandText': Command to execute * `commandParameters': Parameters to use for the command *Return Value* DataSetcontaining the resultset *See Also* *Note MySqlHelper Class: connector-net-ref-mysqlclient-mysqlhelper, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note MySqlHelper.ExecuteDataset Overload List: connector-net-ref-mysqlclient-mysqlhelper-executedataset-overloads.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlhelper-executenonquery-overloads, Next: connector-net-ref-mysqlclient-mysqlhelper-executereader-overloads, Prev: connector-net-ref-mysqlclient-mysqlhelper-executedataset-overloads, Up: connector-net-ref-mysqlclient-mysqlhelpermembers 21.2.7.207 ExecuteNonQuery Method ................................. * Menu: * connector-net-ref-mysqlclient-mysqlhelper-executenonquery-overload-1:: `MySqlHelper.ExecuteNonQuery' Method * connector-net-ref-mysqlclient-mysqlhelper-executenonquery-overload-2:: `MySqlHelper.ExecuteNonQuery' Method Executes a single command against a MySQL database. The *Note MySqlConnection: connector-net-ref-mysqlclient-mysqlconnection. is assumed to be open when the method is called and remains open after the method completes. *Overload List* Executes a single command against a MySQL database. The *Note MySqlConnection: connector-net-ref-mysqlclient-mysqlconnection. is assumed to be open when the method is called and remains open after the method completes. * *Note public static int ExecuteNonQuery(MySqlConnection: (string)connector-net-ref-mysqlclient-mysqlhelper-executenonquery-overload-1. Executes a single command against a MySQL database. A new *Note MySqlConnection: connector-net-ref-mysqlclient-mysqlconnection. is created using the *Note ConnectionString: connector-net-ref-mysqlclient-mysqlconnection-connectionstring. given. * *Note public static int ExecuteNonQuery(string: (string)connector-net-ref-mysqlclient-mysqlhelper-executenonquery-overload-2. *See Also* *Note MySqlHelper Class: connector-net-ref-mysqlclient-mysqlhelper, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlhelper-executenonquery-overload-1, Next: connector-net-ref-mysqlclient-mysqlhelper-executenonquery-overload-2, Prev: connector-net-ref-mysqlclient-mysqlhelper-executenonquery-overloads, Up: connector-net-ref-mysqlclient-mysqlhelper-executenonquery-overloads 21.2.7.208 `MySqlHelper.ExecuteNonQuery' Method ............................................... Executes a single command against a MySQL database. The *Note MySqlConnection: connector-net-ref-mysqlclient-mysqlconnection. is assumed to be open when the method is called and remains open after the method completes. *Syntax: Visual Basic* Overloads Public Shared Function ExecuteNonQuery( _ ByVal connection As MySqlConnection, _ ByVal commandText As String, _ ParamArray commandParameters As MySqlParameter() _ ) As Integer *Syntax: C#* public static int ExecuteNonQuery( MySqlConnectionconnection, stringcommandText, params MySqlParameter[]commandParameters ); *Parameters* * `connection': *Note MySqlConnection: connector-net-ref-mysqlclient-mysqlconnection. object to use * `commandText': SQL statement to be executed * `commandParameters': Array of *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. objects to use with the command. *Return Value* *See Also* *Note MySqlHelper Class: connector-net-ref-mysqlclient-mysqlhelper, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note MySqlHelper.ExecuteNonQuery Overload List: connector-net-ref-mysqlclient-mysqlhelper-executenonquery-overloads.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlhelper-executenonquery-overload-2, Prev: connector-net-ref-mysqlclient-mysqlhelper-executenonquery-overload-1, Up: connector-net-ref-mysqlclient-mysqlhelper-executenonquery-overloads 21.2.7.209 `MySqlHelper.ExecuteNonQuery' Method ............................................... Executes a single command against a MySQL database. A new *Note MySqlConnection: connector-net-ref-mysqlclient-mysqlconnection. is created using the *Note ConnectionString: connector-net-ref-mysqlclient-mysqlconnection-connectionstring. given. *Syntax: Visual Basic* Overloads Public Shared Function ExecuteNonQuery( _ ByVal connectionString As String, _ ByVal commandText As String, _ ParamArray parms As MySqlParameter() _ ) As Integer *Syntax: C#* public static int ExecuteNonQuery( stringconnectionString, stringcommandText, params MySqlParameter[]parms ); *Parameters* * `connectionString': *Note ConnectionString: connector-net-ref-mysqlclient-mysqlconnection-connectionstring. to use * `commandText': SQL statement to be executed * `parms': Array of *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. objects to use with the command. *Return Value* *See Also* *Note MySqlHelper Class: connector-net-ref-mysqlclient-mysqlhelper, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note MySqlHelper.ExecuteNonQuery Overload List: connector-net-ref-mysqlclient-mysqlhelper-executenonquery-overloads.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlhelper-executereader-overloads, Next: connector-net-ref-mysqlclient-mysqlhelper-executescalar-overloads, Prev: connector-net-ref-mysqlclient-mysqlhelper-executenonquery-overloads, Up: connector-net-ref-mysqlclient-mysqlhelpermembers 21.2.7.210 ExecuteReader Method ............................... * Menu: * connector-net-ref-mysqlclient-mysqlhelper-executereader-overload-1:: `MySqlHelper.ExecuteReader' Method * connector-net-ref-mysqlclient-mysqlhelper-executereader-overload-2:: `MySqlHelper.ExecuteReader' Method Executes a single command against a MySQL database. *Overload List* Executes a single command against a MySQL database. * *Note public static MySqlDataReader ExecuteReader(string: (string);)connector-net-ref-mysqlclient-mysqlhelper-executereader-overload-1. Executes a single command against a MySQL database. * *Note public static MySqlDataReader ExecuteReader(string: (string)connector-net-ref-mysqlclient-mysqlhelper-executereader-overload-2. *See Also* *Note MySqlHelper Class: connector-net-ref-mysqlclient-mysqlhelper, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlhelper-executereader-overload-1, Next: connector-net-ref-mysqlclient-mysqlhelper-executereader-overload-2, Prev: connector-net-ref-mysqlclient-mysqlhelper-executereader-overloads, Up: connector-net-ref-mysqlclient-mysqlhelper-executereader-overloads 21.2.7.211 `MySqlHelper.ExecuteReader' Method ............................................. Executes a single command against a MySQL database. *Syntax: Visual Basic* Overloads Public Shared Function ExecuteReader( _ ByVal connectionString As String, _ ByVal commandText As String _ ) As MySqlDataReader *Syntax: C#* public static MySqlDataReader ExecuteReader( stringconnectionString, stringcommandText ); *Parameters* * `connectionString': Settings to use for this command * `commandText': Command text to use *Return Value* *Note MySqlDataReader: connector-net-ref-mysqlclient-mysqldatareader. object ready to read the results of the command *See Also* *Note MySqlHelper Class: connector-net-ref-mysqlclient-mysqlhelper, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note MySqlHelper.ExecuteReader Overload List: connector-net-ref-mysqlclient-mysqlhelper-executereader-overloads.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlhelper-executereader-overload-2, Prev: connector-net-ref-mysqlclient-mysqlhelper-executereader-overload-1, Up: connector-net-ref-mysqlclient-mysqlhelper-executereader-overloads 21.2.7.212 `MySqlHelper.ExecuteReader' Method ............................................. Executes a single command against a MySQL database. *Syntax: Visual Basic* Overloads Public Shared Function ExecuteReader( _ ByVal connectionString As String, _ ByVal commandText As String, _ ParamArray commandParameters As MySqlParameter() _ ) As MySqlDataReader *Syntax: C#* public static MySqlDataReader ExecuteReader( stringconnectionString, stringcommandText, params MySqlParameter[]commandParameters ); *Parameters* * `connectionString': Settings to use for this command * `commandText': Command text to use * `commandParameters': Array of *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter. objects to use with the command *Return Value* *Note MySqlDataReader: connector-net-ref-mysqlclient-mysqldatareader. object ready to read the results of the command *See Also* *Note MySqlHelper Class: connector-net-ref-mysqlclient-mysqlhelper, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note MySqlHelper.ExecuteReader Overload List: connector-net-ref-mysqlclient-mysqlhelper-executereader-overloads.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlhelper-executescalar-overloads, Next: connector-net-ref-mysqlclient-mysqlhelper-updatedataset, Prev: connector-net-ref-mysqlclient-mysqlhelper-executereader-overloads, Up: connector-net-ref-mysqlclient-mysqlhelpermembers 21.2.7.213 ExecuteScalar Method ............................... * Menu: * connector-net-ref-mysqlclient-mysqlhelper-executescalar-overload-3:: `MySqlHelper.ExecuteScalar' Method * connector-net-ref-mysqlclient-mysqlhelper-executescalar-overload-4:: `MySqlHelper.ExecuteScalar' Method * connector-net-ref-mysqlclient-mysqlhelper-executescalar-overload-1:: `MySqlHelper.ExecuteScalar' Method * connector-net-ref-mysqlclient-mysqlhelper-executescalar-overload-2:: `MySqlHelper.ExecuteScalar' Method Execute a single command against a MySQL database. *Overload List* Execute a single command against a MySQL database. * *Note public static object ExecuteScalar(MySqlConnection: (string);)connector-net-ref-mysqlclient-mysqlhelper-executescalar-overload-3. Execute a single command against a MySQL database. * *Note public static object ExecuteScalar(MySqlConnection: (string)connector-net-ref-mysqlclient-mysqlhelper-executescalar-overload-4. Execute a single command against a MySQL database. * *Note public static object ExecuteScalar(string: (string);)connector-net-ref-mysqlclient-mysqlhelper-executescalar-overload-1. Execute a single command against a MySQL database. * *Note public static object ExecuteScalar(string: (string)connector-net-ref-mysqlclient-mysqlhelper-executescalar-overload-2. *See Also* *Note MySqlHelper Class: connector-net-ref-mysqlclient-mysqlhelper, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlhelper-executescalar-overload-3, Next: connector-net-ref-mysqlclient-mysqlhelper-executescalar-overload-4, Prev: connector-net-ref-mysqlclient-mysqlhelper-executescalar-overloads, Up: connector-net-ref-mysqlclient-mysqlhelper-executescalar-overloads 21.2.7.214 `MySqlHelper.ExecuteScalar' Method ............................................. Execute a single command against a MySQL database. *Syntax: Visual Basic* Overloads Public Shared Function ExecuteScalar( _ ByVal connection As MySqlConnection, _ ByVal commandText As String _ ) As Object *Syntax: C#* public static object ExecuteScalar( MySqlConnectionconnection, stringcommandText ); *Parameters* * `connection': *Note MySqlConnection: connector-net-ref-mysqlclient-mysqlconnection. object to use * `commandText': Command text to use for the command *Return Value* The first column of the first row in the result set, or a null reference if the result set is empty. *See Also* *Note MySqlHelper Class: connector-net-ref-mysqlclient-mysqlhelper, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note MySqlHelper.ExecuteScalar Overload List: connector-net-ref-mysqlclient-mysqlhelper-executescalar-overloads.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlhelper-executescalar-overload-4, Next: connector-net-ref-mysqlclient-mysqlhelper-executescalar-overload-1, Prev: connector-net-ref-mysqlclient-mysqlhelper-executescalar-overload-3, Up: connector-net-ref-mysqlclient-mysqlhelper-executescalar-overloads 21.2.7.215 `MySqlHelper.ExecuteScalar' Method ............................................. Execute a single command against a MySQL database. *Syntax: Visual Basic* Overloads Public Shared Function ExecuteScalar( _ ByVal connection As MySqlConnection, _ ByVal commandText As String, _ ParamArray commandParameters As MySqlParameter() _ ) As Object *Syntax: C#* public static object ExecuteScalar( MySqlConnectionconnection, stringcommandText, params MySqlParameter[]commandParameters ); *Parameters* * `connection': *Note MySqlConnection: connector-net-ref-mysqlclient-mysqlconnection. object to use * `commandText': Command text to use for the command * `commandParameters': Parameters to use for the command *Return Value* The first column of the first row in the result set, or a null reference if the result set is empty. *See Also* *Note MySqlHelper Class: connector-net-ref-mysqlclient-mysqlhelper, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note MySqlHelper.ExecuteScalar Overload List: connector-net-ref-mysqlclient-mysqlhelper-executescalar-overloads.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlhelper-executescalar-overload-1, Next: connector-net-ref-mysqlclient-mysqlhelper-executescalar-overload-2, Prev: connector-net-ref-mysqlclient-mysqlhelper-executescalar-overload-4, Up: connector-net-ref-mysqlclient-mysqlhelper-executescalar-overloads 21.2.7.216 `MySqlHelper.ExecuteScalar' Method ............................................. Execute a single command against a MySQL database. *Syntax: Visual Basic* Overloads Public Shared Function ExecuteScalar( _ ByVal connectionString As String, _ ByVal commandText As String _ ) As Object *Syntax: C#* public static object ExecuteScalar( stringconnectionString, stringcommandText ); *Parameters* * `connectionString': Settings to use for the update * `commandText': Command text to use for the update *Return Value* The first column of the first row in the result set, or a null reference if the result set is empty. *See Also* *Note MySqlHelper Class: connector-net-ref-mysqlclient-mysqlhelper, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note MySqlHelper.ExecuteScalar Overload List: connector-net-ref-mysqlclient-mysqlhelper-executescalar-overloads.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlhelper-executescalar-overload-2, Prev: connector-net-ref-mysqlclient-mysqlhelper-executescalar-overload-1, Up: connector-net-ref-mysqlclient-mysqlhelper-executescalar-overloads 21.2.7.217 `MySqlHelper.ExecuteScalar' Method ............................................. Execute a single command against a MySQL database. *Syntax: Visual Basic* Overloads Public Shared Function ExecuteScalar( _ ByVal connectionString As String, _ ByVal commandText As String, _ ParamArray commandParameters As MySqlParameter() _ ) As Object *Syntax: C#* public static object ExecuteScalar( stringconnectionString, stringcommandText, params MySqlParameter[]commandParameters ); *Parameters* * `connectionString': Settings to use for the command * `commandText': Command text to use for the command * `commandParameters': Parameters to use for the command *Return Value* The first column of the first row in the result set, or a null reference if the result set is empty. *See Also* *Note MySqlHelper Class: connector-net-ref-mysqlclient-mysqlhelper, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note MySqlHelper.ExecuteScalar Overload List: connector-net-ref-mysqlclient-mysqlhelper-executescalar-overloads.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlhelper-updatedataset, Prev: connector-net-ref-mysqlclient-mysqlhelper-executescalar-overloads, Up: connector-net-ref-mysqlclient-mysqlhelpermembers 21.2.7.218 `MySqlHelper.UpdateDataSet' Method ............................................. Updates the given table with data from the given DataSet *Syntax: Visual Basic* Public Shared Sub UpdateDataSet( _ ByVal connectionString As String, _ ByVal commandText As String, _ ByVal ds As DataSet, _ ByVal tablename As String _ ) *Syntax: C#* public static void UpdateDataSet( stringconnectionString, stringcommandText, DataSetds, stringtablename ); *Parameters* * `connectionString': Settings to use for the update * `commandText': Command text to use for the update * `ds': DataSetcontaining the new data to use in the update * `tablename': Tablename in the data set to update *See Also* *Note MySqlHelper Class: connector-net-ref-mysqlclient-mysqlhelper, *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-mysqlclient-mysqlerrorcode, Prev: connector-net-ref-mysqlclient-mysqlhelper, Up: connector-net-ref-mysqlclient 21.2.7.219 `MySqlErrorCode' Enumeration ....................................... *Syntax: Visual Basic* Public Enum MySqlErrorCode *Syntax: C#* public enum MySqlErrorCode *Members* *Member Name* *Description* PacketTooLarge PasswordNotAllowed DuplicateKeyEntry HostNotPrivileged PasswordNoMatch AnonymousUser DuplicateKey KeyNotFound DuplicateKeyName *Requirements* Namespace: *Note MySql.Data.MySqlClient: connector-net-ref-mysqlclient. Assembly: MySql.Data (in MySql.Data.dll) *See Also* *Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.  File: manual.info, Node: connector-net-ref-types, Prev: connector-net-ref-mysqlclient, Up: connector-net-ref 21.2.7.220 `MySql.Data.Types' ............................. * Menu: * connector-net-ref-typeshierarchy:: `MySql.Data.TypesHierarchy' * connector-net-ref-types-mysqlconversionexception:: `MySqlConversionException' Class * connector-net-ref-types-mysqldatetime:: `MySqlDateTime' Class *Note Namespace hierarchy: connector-net-ref-typeshierarchy. *Classes* *Class* *Description* *Note MySqlConversionException: Summary description for connector-net-ref-types-mysqlconversionexception.MySqlConversionException. *Note MySqlDateTime: Summary description for connector-net-ref-types-mysqldatetime.MySqlDateTime. *Note MySqlValue: connector-net-ref-types-mysqlvalue.  File: manual.info, Node: connector-net-ref-typeshierarchy, Next: connector-net-ref-types-mysqlconversionexception, Prev: connector-net-ref-types, Up: connector-net-ref-types 21.2.7.221 `MySql.Data.TypesHierarchy' ...................................... *See Also* *Note MySql.Data.Types Namespace: connector-net-ref-types.  File: manual.info, Node: connector-net-ref-types-mysqlconversionexception, Next: connector-net-ref-types-mysqldatetime, Prev: connector-net-ref-typeshierarchy, Up: connector-net-ref-types 21.2.7.222 `MySqlConversionException' Class ........................................... * Menu: * connector-net-ref-types-mysqlconversionexceptionmembers:: `MySqlConversionException' Members Summary description for MySqlConversionException. For a list of all members of this type, see *Note MySqlConversionException Members: connector-net-ref-types-mysqlconversionexceptionmembers . *Syntax: Visual Basic* Public Class MySqlConversionException_ Inherits ApplicationException *Syntax: C#* public class MySqlConversionException : ApplicationException *Thread Safety* Public static (Sharedin Visual Basic) members of this type are safe for multithreaded operations. Instance members are notguaranteed to be thread-safe. *Requirements* Namespace: *Note MySql.Data.Types: connector-net-ref-types. Assembly: MySql.Data (in MySql.Data.dll) *See Also* *Note MySqlConversionException Members: connector-net-ref-types-mysqlconversionexceptionmembers, *Note MySql.Data.Types Namespace: connector-net-ref-types.  File: manual.info, Node: connector-net-ref-types-mysqlconversionexceptionmembers, Prev: connector-net-ref-types-mysqlconversionexception, Up: connector-net-ref-types-mysqlconversionexception 21.2.7.223 `MySqlConversionException' Members ............................................. * Menu: * connector-net-ref-types-mysqlconversionexceptionconstructor:: `MySqlConversionException' Constructor *Note MySqlConversionException overview: connector-net-ref-types-mysqlconversionexception. *Public Instance Constructors* *Note MySqlConversionException Ctor Constructor: connector-net-ref-types-mysqlconversionexceptionconstructor. *Public Instance Properties* Data(inherited from Exception) Gets a collection of key/value pairs that provide additional, user-defined information about the exception. HelpLink(inherited from Exception) Gets or sets a link to the help file associated with this exception. InnerException(inherited from Gets the Exceptioninstance that Exception) caused the current exception. Message(inherited from Exception) Gets a message that describes the current exception. Source(inherited from Exception) Gets or sets the name of the application or the object that causes the error. StackTrace(inherited from Exception) Gets a string representation of the frames on the call stack at the time the current exception was thrown. TargetSite(inherited from Exception) Gets the method that throws the current exception. *Public Instance Methods* Equals(inherited from Object) Determines whether the specified Objectis equal to the current Object. GetBaseException(inherited from When overridden in a derived class, Exception) returns the Exceptionthat is the root cause of one or more subsequent exceptions. GetHashCode(inherited from Object) Serves as a hash function for a particular type. GetHashCodeis suitable for use in hashing algorithms and data structures like a hash table. GetObjectData(inherited from When overridden in a derived class, Exception) sets the SerializationInfowith information about the exception. GetType(inherited from Exception) Gets the runtime type of the current instance. ToString(inherited from Exception) Creates and returns a string representation of the current exception. *Protected Instance Properties* HResult(inherited from Exception) Gets or sets HRESULT, a coded numeric value that is assigned to a specific exception. *Protected Instance Methods* Finalize(inherited from Object) Allows an Objectto attempt to free resources and perform other cleanup operations before the Objectis reclaimed by garbage collection. MemberwiseClone(inherited from Creates a shallow copy of the Object) current Object. *See Also* *Note MySqlConversionException Class: connector-net-ref-types-mysqlconversionexception, *Note MySql.Data.Types Namespace: connector-net-ref-types.  File: manual.info, Node: connector-net-ref-types-mysqlconversionexceptionconstructor, Prev: connector-net-ref-types-mysqlconversionexceptionmembers, Up: connector-net-ref-types-mysqlconversionexceptionmembers 21.2.7.224 `MySqlConversionException' Constructor ................................................. *Syntax: Visual Basic* Public Sub New( _ ByVal msg As String _ ) *Syntax: C#* public MySqlConversionException( stringmsg ); *See Also* *Note MySqlConversionException Class: connector-net-ref-types-mysqlconversionexception, *Note MySql.Data.Types Namespace: connector-net-ref-types.  File: manual.info, Node: connector-net-ref-types-mysqldatetime, Prev: connector-net-ref-types-mysqlconversionexception, Up: connector-net-ref-types 21.2.7.225 `MySqlDateTime' Class ................................ * Menu: * connector-net-ref-types-mysqldatetimemembers:: `MySqlDateTime' Members Summary description for MySqlDateTime. For a list of all members of this type, see *Note MySqlDateTime Members: connector-net-ref-types-mysqldatetimemembers . *Syntax: Visual Basic* Public Class MySqlDateTime_ Inherits MySqlValue_ Implements IConvertible, IComparable *Syntax: C#* public class MySqlDateTime : MySqlValue, IConvertible, IComparable *Thread Safety* Public static (Shared in Visual Basic) members of this type are safe for multithreaded operations. Instance members are not guaranteed to be thread-safe. *Requirements* Namespace: *Note MySql.Data.Types: connector-net-ref-types. Assembly: MySql.Data (in MySql.Data.dll) *See Also* *Note MySqlDateTime Members: connector-net-ref-types-mysqldatetimemembers, *Note MySql.Data.Types Namespace: connector-net-ref-types.  File: manual.info, Node: connector-net-ref-types-mysqldatetimemembers, Prev: connector-net-ref-types-mysqldatetime, Up: connector-net-ref-types-mysqldatetime 21.2.7.226 `MySqlDateTime' Members .................................. * Menu: * connector-net-ref-types-mysqldatetime-op-explicit:: `MySqlDateTime' Explicit `MySqlDateTime' to `DateTime' Conversion * connector-net-ref-types-mysqldatetime-day:: Day Property * connector-net-ref-types-mysqldatetime-hour:: Hour Property * connector-net-ref-types-mysqlvalue-isnull:: IsNull Property * connector-net-ref-types-mysqldatetime-isvaliddatetime:: IsValidDateTime Property * connector-net-ref-types-mysqldatetime-minute:: Minute Property * connector-net-ref-types-mysqldatetime-month:: Month Property * connector-net-ref-types-mysqldatetime-second:: Second Property * connector-net-ref-types-mysqldatetime-year:: Year Property * connector-net-ref-types-mysqldatetime-getdatetime:: `MySqlDateTime.GetDateTime' Method * connector-net-ref-types-mysqldatetime-tostring:: `MySqlDateTime.ToString' Method *Note MySqlDateTime overview: connector-net-ref-types-mysqldatetime. *Public Static (Shared) Type Conversions* *Note Explicit MySqlDateTime to DateTime Conversion: connector-net-ref-types-mysqldatetime-op-explicit. *Public Instance Properties* *Note Day: Returns the day portion of this connector-net-ref-types-mysqldatetime-day.datetime *Note Hour: Returns the hour portion of this connector-net-ref-types-mysqldatetime-hour.datetime *Note IsNull: connector-net-ref-types-mysqlvalue-isnull. (inherited from MySqlValue) *Note IsValidDateTime: Indicates if this object contains a connector-net-ref-types-mysqldatetime-isvaliddatetime.value that can be represented as a DateTime *Note Minute: Returns the minute portion of this connector-net-ref-types-mysqldatetime-minute.datetime *Note Month: Returns the month portion of this connector-net-ref-types-mysqldatetime-month.datetime *Note Second: Returns the second portion of this connector-net-ref-types-mysqldatetime-second.datetime *Note ValueAsObject: Returns the value of this field as connector-net-ref-types-mysqlvalue-valueasobject.an object (inherited from MySqlValue) *Note Year: Returns the year portion of this connector-net-ref-types-mysqldatetime-year.datetime *Public Instance Methods* Equals(inherited from Object) Determines whether the specified Objectis equal to the current Object. *Note GetDateTime: Returns this value as a DateTime connector-net-ref-types-mysqldatetime-getdatetime. GetHashCode(inherited from Object) Serves as a hash function for a particular type. GetHashCodeis suitable for use in hashing algorithms and data structures like a hash table. GetType(inherited from Object) Gets the Typeof the current instance. *Note ToString: Returns a MySQL specific string connector-net-ref-types-mysqldatetime-tostring.representation of this value *Protected Instance Fields* *Note classType: The system type represented by this connector-net-ref-types-mysqlvalue-classtype.value (inherited from MySqlValue) *Note dbType: The generic dbtype of this value connector-net-ref-types-mysqlvalue-dbtype. (inherited from MySqlValue) *Note isNull: Is this value null connector-net-ref-types-mysqlvalue-isnull. (inherited from MySqlValue) *Note mySqlDbType: The specific MySQL db type connector-net-ref-types-mysqlvalue-mysqldbtype. (inherited from MySqlValue) *Note mySqlTypeName: The MySQL specific typename of this connector-net-ref-types-mysqlvalue-mysqltypename.value (inherited from MySqlValue) *Note objectValue: connector-net-ref-types-mysqlvalue-objectvalue. (inherited from MySqlValue) *Protected Instance Methods* Finalize(inherited from Object) Allows an Objectto attempt to free resources and perform other cleanup operations before the Objectis reclaimed by garbage collection. MemberwiseClone(inherited from Creates a shallow copy of the Object) current Object. *See Also* *Note MySqlDateTime Class: connector-net-ref-types-mysqldatetime, *Note MySql.Data.Types Namespace: connector-net-ref-types.  File: manual.info, Node: connector-net-ref-types-mysqldatetime-op-explicit, Next: connector-net-ref-types-mysqldatetime-day, Prev: connector-net-ref-types-mysqldatetimemembers, Up: connector-net-ref-types-mysqldatetimemembers 21.2.7.227 `MySqlDateTime' Explicit `MySqlDateTime' to `DateTime' Conversion ............................................................................ *Syntax: Visual Basic* MySqlDateTime.op_Explicit(val) *Syntax: C#* public static explicit operator DateTime( MySqlDateTimeval ); *Parameters* * `val': *Return Value* *See Also* *Note MySqlDateTime Class: connector-net-ref-types-mysqldatetime, *Note MySql.Data.Types Namespace: connector-net-ref-types.  File: manual.info, Node: connector-net-ref-types-mysqldatetime-day, Next: connector-net-ref-types-mysqldatetime-hour, Prev: connector-net-ref-types-mysqldatetime-op-explicit, Up: connector-net-ref-types-mysqldatetimemembers 21.2.7.228 Day Property ....................... Returns the day portion of this datetime *Syntax: Visual Basic* Public Property Day As Integer *Syntax: C#* public int Day {get; set;} *See Also* *Note MySqlDateTime Class: connector-net-ref-types-mysqldatetime, *Note MySql.Data.Types Namespace: connector-net-ref-types.  File: manual.info, Node: connector-net-ref-types-mysqldatetime-hour, Next: connector-net-ref-types-mysqlvalue-isnull, Prev: connector-net-ref-types-mysqldatetime-day, Up: connector-net-ref-types-mysqldatetimemembers 21.2.7.229 Hour Property ........................ Returns the hour portion of this datetime *Syntax: Visual Basic* Public Property Hour As Integer *Syntax: C#* public int Hour {get; set;} *See Also* *Note MySqlDateTime Class: connector-net-ref-types-mysqldatetime, *Note MySql.Data.Types Namespace: connector-net-ref-types.  File: manual.info, Node: connector-net-ref-types-mysqlvalue-isnull, Next: connector-net-ref-types-mysqldatetime-isvaliddatetime, Prev: connector-net-ref-types-mysqldatetime-hour, Up: connector-net-ref-types-mysqldatetimemembers 21.2.7.230 IsNull Property .......................... * Menu: * connector-net-ref-types-mysqlvalue:: `MySqlValue' Class *Syntax: Visual Basic* Public Property IsNull As Boolean *Syntax: C#* public bool IsNull {get; set;} *See Also* *Note MySqlValue Class: connector-net-ref-types-mysqlvalue, *Note MySql.Data.Types Namespace: connector-net-ref-types.  File: manual.info, Node: connector-net-ref-types-mysqlvalue, Prev: connector-net-ref-types-mysqlvalue-isnull, Up: connector-net-ref-types-mysqlvalue-isnull 21.2.7.231 `MySqlValue' Class ............................. * Menu: * connector-net-ref-types-mysqlvaluemembers:: `MySqlValue' Members For a list of all members of this type, see *Note MySqlValue Members: connector-net-ref-types-mysqlvaluemembers . *Syntax: Visual Basic* MustInherit Public Class MySqlValue *Syntax: C#* public abstract class MySqlValue *Thread Safety* Public static (Shared in Visual Basic) members of this type are safe for multithreaded operations. Instance members are not guaranteed to be thread-safe. *Requirements* Namespace: *Note MySql.Data.Types: connector-net-ref-types. Assembly: MySql.Data (in MySql.Data.dll) *See Also* *Note MySqlValue Members: connector-net-ref-types-mysqlvaluemembers, *Note MySql.Data.Types Namespace: connector-net-ref-types.  File: manual.info, Node: connector-net-ref-types-mysqlvaluemembers, Prev: connector-net-ref-types-mysqlvalue, Up: connector-net-ref-types-mysqlvalue 21.2.7.232 `MySqlValue' Members ............................... * Menu: * connector-net-ref-types-mysqlvalue-numberformat:: `MySqlValue.numberFormat' Field * connector-net-ref-types-mysqlvalueconstructor:: `MySqlValue' Constructor * connector-net-ref-types-mysqlvalue-valueasobject:: ValueAsObject Property * connector-net-ref-types-mysqlvalue-tostring:: `MySqlValue.ToString' Method * connector-net-ref-types-mysqlvalue-classtype:: `MySqlValue.classType' Field * connector-net-ref-types-mysqlvalue-dbtype:: `MySqlValue.dbType' Field * connector-net-ref-types-mysqlvalue-mysqldbtype:: `MySqlValue.mySqlDbType' Field * connector-net-ref-types-mysqlvalue-mysqltypename:: `MySqlValue.mySqlTypeName' Field * connector-net-ref-types-mysqlvalue-objectvalue:: `MySqlValue.objectValue' Field *Note MySqlValue overview: connector-net-ref-types-mysqlvalue. *Protected Static (Shared) Fields* *Note numberFormat: connector-net-ref-types-mysqlvalue-numberformat. *Public Instance Constructors* *Note MySqlValue Constructor: Initializes a new instance of the connector-net-ref-types-mysqlvalueconstructor.*Note MySqlValue: connector-net-ref-types-mysqlvalue. class. *Public Instance Properties* *Note IsNull: connector-net-ref-types-mysqlvalue-isnull. *Note ValueAsObject: Returns the value of this field as connector-net-ref-types-mysqlvalue-valueasobject.an object *Public Instance Methods* Equals(inherited from Object) Determines whether the specified Objectis equal to the current Object. GetHashCode(inherited from Object) Serves as a hash function for a particular type. GetHashCodeis suitable for use in hashing algorithms and data structures like a hash table. GetType(inherited from Object) Gets the Typeof the current instance. *Note ToString: Returns a string representation of connector-net-ref-types-mysqlvalue-tostring.this value *Protected Instance Fields* *Note classType: The system type represented by this connector-net-ref-types-mysqlvalue-classtype.value *Note dbType: The generic dbtype of this value connector-net-ref-types-mysqlvalue-dbtype. *Note isNull: Is this value null connector-net-ref-types-mysqlvalue-isnull. *Note mySqlDbType: The specific MySQL db type connector-net-ref-types-mysqlvalue-mysqldbtype. *Note mySqlTypeName: The MySQL specific typename of this connector-net-ref-types-mysqlvalue-mysqltypename.value *Note objectValue: connector-net-ref-types-mysqlvalue-objectvalue. *Protected Instance Methods* Finalize(inherited from Object) Allows an Objectto attempt to free resources and perform other cleanup operations before the Objectis reclaimed by garbage collection. MemberwiseClone(inherited from Creates a shallow copy of the Object) current Object. *See Also* *Note MySqlValue Class: connector-net-ref-types-mysqlvalue, *Note MySql.Data.Types Namespace: connector-net-ref-types.  File: manual.info, Node: connector-net-ref-types-mysqlvalue-numberformat, Next: connector-net-ref-types-mysqlvalueconstructor, Prev: connector-net-ref-types-mysqlvaluemembers, Up: connector-net-ref-types-mysqlvaluemembers 21.2.7.233 `MySqlValue.numberFormat' Field .......................................... *Syntax: Visual Basic* Protected Shared numberFormat As NumberFormatInfo *Syntax: C#* protected static NumberFormatInfo numberFormat; *See Also* *Note MySqlValue Class: connector-net-ref-types-mysqlvalue, *Note MySql.Data.Types Namespace: connector-net-ref-types.  File: manual.info, Node: connector-net-ref-types-mysqlvalueconstructor, Next: connector-net-ref-types-mysqlvalue-valueasobject, Prev: connector-net-ref-types-mysqlvalue-numberformat, Up: connector-net-ref-types-mysqlvaluemembers 21.2.7.234 `MySqlValue' Constructor ................................... Initializes a new instance of the *Note MySqlValue: connector-net-ref-types-mysqlvalue. class. *Syntax: Visual Basic* Public Sub New() *Syntax: C#* public MySqlValue(); *See Also* *Note MySqlValue Class: connector-net-ref-types-mysqlvalue, *Note MySql.Data.Types Namespace: connector-net-ref-types.  File: manual.info, Node: connector-net-ref-types-mysqlvalue-valueasobject, Next: connector-net-ref-types-mysqlvalue-tostring, Prev: connector-net-ref-types-mysqlvalueconstructor, Up: connector-net-ref-types-mysqlvaluemembers 21.2.7.235 ValueAsObject Property ................................. Returns the value of this field as an object *Syntax: Visual Basic* Public ReadOnly Property ValueAsObject As Object *Syntax: C#* public object ValueAsObject {get;} *See Also* *Note MySqlValue Class: connector-net-ref-types-mysqlvalue, *Note MySql.Data.Types Namespace: connector-net-ref-types.  File: manual.info, Node: connector-net-ref-types-mysqlvalue-tostring, Next: connector-net-ref-types-mysqlvalue-classtype, Prev: connector-net-ref-types-mysqlvalue-valueasobject, Up: connector-net-ref-types-mysqlvaluemembers 21.2.7.236 `MySqlValue.ToString' Method ....................................... Returns a string representation of this value *Syntax: Visual Basic* Overrides Public Function ToString() As String *Syntax: C#* public override string ToString(); *See Also* *Note MySqlValue Class: connector-net-ref-types-mysqlvalue, *Note MySql.Data.Types Namespace: connector-net-ref-types.  File: manual.info, Node: connector-net-ref-types-mysqlvalue-classtype, Next: connector-net-ref-types-mysqlvalue-dbtype, Prev: connector-net-ref-types-mysqlvalue-tostring, Up: connector-net-ref-types-mysqlvaluemembers 21.2.7.237 `MySqlValue.classType' Field ....................................... The system type represented by this value *Syntax: Visual Basic* Protected classType As Type *Syntax: C#* protected Type classType; *See Also* *Note MySqlValue Class: connector-net-ref-types-mysqlvalue, *Note MySql.Data.Types Namespace: connector-net-ref-types.  File: manual.info, Node: connector-net-ref-types-mysqlvalue-dbtype, Next: connector-net-ref-types-mysqlvalue-mysqldbtype, Prev: connector-net-ref-types-mysqlvalue-classtype, Up: connector-net-ref-types-mysqlvaluemembers 21.2.7.238 `MySqlValue.dbType' Field .................................... The generic dbtype of this value *Syntax: Visual Basic* Protected dbType As DbType *Syntax: C#* protected DbType dbType; *See Also* *Note MySqlValue Class: connector-net-ref-types-mysqlvalue, *Note MySql.Data.Types Namespace: connector-net-ref-types.  File: manual.info, Node: connector-net-ref-types-mysqlvalue-mysqldbtype, Next: connector-net-ref-types-mysqlvalue-mysqltypename, Prev: connector-net-ref-types-mysqlvalue-dbtype, Up: connector-net-ref-types-mysqlvaluemembers 21.2.7.239 `MySqlValue.mySqlDbType' Field ......................................... The specific MySQL db type *Syntax: Visual Basic* Protected mySqlDbType As MySqlDbType *Syntax: C#* protected MySqlDbType mySqlDbType; *See Also* *Note MySqlValue Class: connector-net-ref-types-mysqlvalue, *Note MySql.Data.Types Namespace: connector-net-ref-types.  File: manual.info, Node: connector-net-ref-types-mysqlvalue-mysqltypename, Next: connector-net-ref-types-mysqlvalue-objectvalue, Prev: connector-net-ref-types-mysqlvalue-mysqldbtype, Up: connector-net-ref-types-mysqlvaluemembers 21.2.7.240 `MySqlValue.mySqlTypeName' Field ........................................... The MySQL specific typename of this value *Syntax: Visual Basic* Protected mySqlTypeName As String *Syntax: C#* protected string mySqlTypeName; *See Also* *Note MySqlValue Class: connector-net-ref-types-mysqlvalue, *Note MySql.Data.Types Namespace: connector-net-ref-types.  File: manual.info, Node: connector-net-ref-types-mysqlvalue-objectvalue, Prev: connector-net-ref-types-mysqlvalue-mysqltypename, Up: connector-net-ref-types-mysqlvaluemembers 21.2.7.241 `MySqlValue.objectValue' Field ......................................... *Syntax: Visual Basic* Protected objectValue As Object *Syntax: C#* protected object objectValue; *See Also* *Note MySqlValue Class: connector-net-ref-types-mysqlvalue, *Note MySql.Data.Types Namespace: connector-net-ref-types.  File: manual.info, Node: connector-net-ref-types-mysqldatetime-isvaliddatetime, Next: connector-net-ref-types-mysqldatetime-minute, Prev: connector-net-ref-types-mysqlvalue-isnull, Up: connector-net-ref-types-mysqldatetimemembers 21.2.7.242 IsValidDateTime Property ................................... Indicates if this object contains a value that can be represented as a DateTime *Syntax: Visual Basic* Public ReadOnly Property IsValidDateTime As Boolean *Syntax: C#* public bool IsValidDateTime {get;} *See Also* *Note MySqlDateTime Class: connector-net-ref-types-mysqldatetime, *Note MySql.Data.Types Namespace: connector-net-ref-types.  File: manual.info, Node: connector-net-ref-types-mysqldatetime-minute, Next: connector-net-ref-types-mysqldatetime-month, Prev: connector-net-ref-types-mysqldatetime-isvaliddatetime, Up: connector-net-ref-types-mysqldatetimemembers 21.2.7.243 Minute Property .......................... Returns the minute portion of this datetime *Syntax: Visual Basic* Public Property Minute As Integer *Syntax: C#* public int Minute {get; set;} *See Also* *Note MySqlDateTime Class: connector-net-ref-types-mysqldatetime, *Note MySql.Data.Types Namespace: connector-net-ref-types.  File: manual.info, Node: connector-net-ref-types-mysqldatetime-month, Next: connector-net-ref-types-mysqldatetime-second, Prev: connector-net-ref-types-mysqldatetime-minute, Up: connector-net-ref-types-mysqldatetimemembers 21.2.7.244 Month Property ......................... Returns the month portion of this datetime *Syntax: Visual Basic* Public Property Month As Integer *Syntax: C#* public int Month {get; set;} *See Also* *Note MySqlDateTime Class: connector-net-ref-types-mysqldatetime, *Note MySql.Data.Types Namespace: connector-net-ref-types.  File: manual.info, Node: connector-net-ref-types-mysqldatetime-second, Next: connector-net-ref-types-mysqldatetime-year, Prev: connector-net-ref-types-mysqldatetime-month, Up: connector-net-ref-types-mysqldatetimemembers 21.2.7.245 Second Property .......................... Returns the second portion of this datetime *Syntax: Visual Basic* Public Property Second As Integer *Syntax: C#* public int Second {get; set;} *See Also* *Note MySqlDateTime Class: connector-net-ref-types-mysqldatetime, *Note MySql.Data.Types Namespace: connector-net-ref-types.  File: manual.info, Node: connector-net-ref-types-mysqldatetime-year, Next: connector-net-ref-types-mysqldatetime-getdatetime, Prev: connector-net-ref-types-mysqldatetime-second, Up: connector-net-ref-types-mysqldatetimemembers 21.2.7.246 Year Property ........................ Returns the year portion of this datetime *Syntax: Visual Basic* Public Property Year As Integer *Syntax: C#* public int Year {get; set;} *See Also* *Note MySqlDateTime Class: connector-net-ref-types-mysqldatetime, *Note MySql.Data.Types Namespace: connector-net-ref-types.  File: manual.info, Node: connector-net-ref-types-mysqldatetime-getdatetime, Next: connector-net-ref-types-mysqldatetime-tostring, Prev: connector-net-ref-types-mysqldatetime-year, Up: connector-net-ref-types-mysqldatetimemembers 21.2.7.247 `MySqlDateTime.GetDateTime' Method ............................................. Returns this value as a DateTime *Syntax: Visual Basic* Public Function GetDateTime() As Date *Syntax: C#* public DateTime GetDateTime(); *See Also* *Note MySqlDateTime Class: connector-net-ref-types-mysqldatetime, *Note MySql.Data.Types Namespace: connector-net-ref-types.  File: manual.info, Node: connector-net-ref-types-mysqldatetime-tostring, Prev: connector-net-ref-types-mysqldatetime-getdatetime, Up: connector-net-ref-types-mysqldatetimemembers 21.2.7.248 `MySqlDateTime.ToString' Method .......................................... Returns a MySQL specific string representation of this value *Syntax: Visual Basic* Overrides Public Function ToString() As String *Syntax: C#* public override string ToString(); *See Also* *Note MySqlDateTime Class: connector-net-ref-types-mysqldatetime, *Note MySql.Data.Types Namespace: connector-net-ref-types.  File: manual.info, Node: connect-net-support, Next: connector-net-faq, Prev: connector-net-ref, Up: connector-net 21.2.8 Connector/NET Support ---------------------------- * Menu: * connector-net-support-community:: Connector/NET Community Support * connector-net-support-bug-report:: How to report Connector/NET Problems or Bugs * connector-net-support-changehistory:: Connector/NET Change History The developers of Connector/NET greatly value the input of our users in the software development process. If you find Connector/NET lacking some feature important to you, or if you discover a bug and need to file a bug report, please use the instructions in *Note bug-reports::.  File: manual.info, Node: connector-net-support-community, Next: connector-net-support-bug-report, Prev: connect-net-support, Up: connect-net-support 21.2.8.1 Connector/NET Community Support ........................................ * Community support for Connector/NET can be found through the forums at `http://forums.mysql.com'. * Community support for Connector/NET can also be found through the mailing lists at `http://lists.mysql.com'. * Paid support is available from Oracle. Additional information is available at `http://dev.mysql.com/support/'.  File: manual.info, Node: connector-net-support-bug-report, Next: connector-net-support-changehistory, Prev: connector-net-support-community, Up: connect-net-support 21.2.8.2 How to report Connector/NET Problems or Bugs ..................................................... If you encounter difficulties or problems with Connector/NET, contact the Connector/NET community *Note connector-net-support-community::. You should first try to execute the same SQL statements and commands from the *Note `mysql': mysql. client program or from `admndemo'. This helps you determine whether the error is in Connector/NET or MySQL. If reporting a problem, you should ideally include the following information with the email: * Operating system and version * Connector/NET version * MySQL server version * Copies of error messages or other unexpected output * Simple reproducible sample Remember that the more information you can supply to us, the more likely it is that we can fix the problem. If you believe the problem to be a bug, then you must report the bug through `http://bugs.mysql.com/'.  File: manual.info, Node: connector-net-support-changehistory, Prev: connector-net-support-bug-report, Up: connect-net-support 21.2.8.3 Connector/NET Change History ..................................... The Connector/NET Change History (Changelog) is located with the main Changelog for MySQL. See *Note connector-net-news::.  File: manual.info, Node: connector-net-faq, Prev: connect-net-support, Up: connector-net 21.2.9 Connector/NET FAQ ------------------------ *Questions* * 21.2.9.1: How do I obtain the value of an auto-incremented column? *Questions and Answers* *21.2.9.1: ** How do I obtain the value of an auto-incremented column? * When using CommandBuilder, setting `ReturnGeneratedIdentifiers' property to `true' no longer works, as CommandBuilder does not add `last_insert_id()' by default. CommandBuilder hooks up to the DataAdapter.RowUpdating event handler, which means it will get called for every row. It examines the command object and, if it is the same referenced object, it essentially rebuilds the object, thereby destroying your command text changes. One approach to solving this problem is to clone the command object so you have a different actual reference: dataAdapter.InsertCommand = cb.GetInsertCommand().Clone() This will work, but since the CommandBuilder is still connected to the DataAdapter, the RowUpdating event will still fire and performance will be hit. To stop that, once all your commands have been added you need to disconnect the CommandBuilder from the DataAdapter: cb.DataAdapter = null; The last requirement is to make sure the `id' that is returned by `last_insert_id()' has the correct name. For example: SELECT last_insert_id() AS id A complete working example is shown here: using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Data; using MySql.Data; using MySql.Data.MySqlClient; namespace GetAutoIncId { class Program { static void Main(string[] args) { string connStr = "server=localhost;user=root;database=TestDB;port=3306;password=******;"; MySqlConnection conn = new MySqlConnection(connStr); try { Console.WriteLine("Connecting to MySQL..."); conn.Open(); string sql = "SELECT * FROM TestTable"; MySqlDataAdapter da = new MySqlDataAdapter(sql, conn); MySqlCommandBuilder cb = new MySqlCommandBuilder(da); MySqlCommand cmd = new MySqlCommand(); cmd.Connection = conn; cmd.CommandText = sql; // use Cloned object to avoid .NET rebuilding the object, and // thereby throwing away our command text additions. MySqlCommand insertCmd = cb.GetInsertCommand().Clone(); insertCmd.CommandText = insertCmd.CommandText + ";SELECT last_insert_id() AS id"; insertCmd.UpdatedRowSource = UpdateRowSource.FirstReturnedRecord; da.InsertCommand = insertCmd; cb.DataAdapter = null; // Unhook RowUpdating event handler DataTable dt = new DataTable(); da.Fill(dt); DataRow row = dt.NewRow(); row["name"] = "Joe Smith"; dt.Rows.Add(row); da.Update(dt); System.Console.WriteLine("ID after update: " + row["id"]); } catch (Exception ex) { Console.WriteLine(ex.ToString()); } conn.Close(); Console.WriteLine("Done."); } } }  File: manual.info, Node: connector-j, Next: connector-mxj, Prev: connector-net, Up: connectors-apis 21.3 MySQL Connector/J ====================== * Menu: * connector-j-versions:: Connector/J Versions * connector-j-installing:: Connector/J Installation * connector-j-examples:: Connector/J Examples * connector-j-reference:: Connector/J (JDBC) Reference * connector-j-usagenotes:: Connector/J Notes and Tips * connector-j-support:: Connector/J Support MySQL provides connectivity for client applications developed in the Java programming language through a JDBC driver, which is called MySQL Connector/J. MySQL Connector/J is a JDBC Type 4 driver. Different versions are available that are compatible with the JDBC 3.0 and JDBC 4.0 specifications. The Type 4 designation means that the driver is pure-Java implementation of the MySQL protocol and does not rely on the MySQL client libraries. Although JDBC is useful by itself, we would hope that if you are not familiar with JDBC that after reading the first few sections of this manual, that you would avoid using naked JDBC for all but the most trivial problems and consider using one of the popular persistence frameworks such as Hibernate (http://www.hibernate.org/), Spring's JDBC templates (http://www.springframework.org/) or Ibatis SQL Maps (http://ibatis.apache.org/) to do the majority of repetitive work and heavier lifting that is sometimes required with JDBC. This section is not designed to be a complete JDBC tutorial. If you need more information about using JDBC you might be interested in the following online tutorials that are more in-depth than the information presented here: * JDBC Basics (http://java.sun.com/docs/books/tutorial/jdbc/basics/index.html): A tutorial from Sun covering beginner topics in JDBC * JDBC Short Course (http://java.sun.com/developer/onlineTraining/Database/JDBCShortCourse/index.html): A more in-depth tutorial from Sun and JGuru *Key topics:* * For help with connection strings, connection options setting up your connection through JDBC, see *Note connector-j-reference-configuration-properties::. * For tips on using Connector/J and JDBC with generic J2EE toolkits, see *Note connector-j-usagenotes-j2ee::. * Developers using the Tomcat server platform, see *Note connector-j-usagenotes-tomcat::. * Developers using JBoss, see *Note connector-j-usagenotes-jboss::. * Developers using Spring, see *Note connector-j-usagenotes-spring-config::. * Developers using GlassFish (Sun Application Server), see *Note connector-j-usagenotes-glassfish-config::.  File: manual.info, Node: connector-j-versions, Next: connector-j-installing, Prev: connector-j, Up: connector-j 21.3.1 Connector/J Versions --------------------------- * Menu: * connector-j-versions-java:: Java Versions Supported There are currently four versions of MySQL Connector/J available: * Connector/J 5.1 is the Type 4 pure Java JDBC driver, which conforms to the JDBC 3.0 and JDBC 4.0 specifications. It provides compatibility with all the functionality of MySQL, including 4.1, 5.0, 5.1, 5.4 and 5.5. Connector/J 5.1 provides ease of development features, including auto-registration with the Driver Manager, standardized validity checks, categorized SQLExceptions, support for the JDBC-4.0 XML processing, per connection client information, *Note `NCHAR': char, *Note `NVARCHAR': char. and `NCLOB' types. This release also includes all bug fixes up to and including Connector/J 5.0.6. * Connector/J 5.0 provides support for all the functionality offered by Connector/J 3.1 and includes distributed transaction (XA) support. * Connector/J 3.1 was designed for connectivity to MySQL 4.1 and MySQL 5.0 servers and provides support for all the functionality in MySQL 5.0 except distributed transaction (XA) support. * Connector/J 3.0 provides core functionality and was designed with connectivity to MySQL 3.x or MySQL 4.1 servers, although it will provide basic compatibility with later versions of MySQL. Connector/J 3.0 does not support server-side prepared statements, and does not support any of the features in versions of MySQL later than 4.1. The following table summarizes the Connector/J versions available: Connector/J Driver Type JDBC version MySQL Server Status version version 5.1 4 3.0, 4.0 4.1, 5.0, Recommended 5.1, 5.4, 5.5 version 5.0 4 3.0 4.1, 5.0 Released version 3.1 4 3.0 4.1, 5.0 Obsolete 3.0 4 3.0 3.x, 4.1 Obsolete The current recommended version for Connector/J is 5.1. This guide covers all four connector versions, with specific notes given where a setting applies to a specific option.  File: manual.info, Node: connector-j-versions-java, Prev: connector-j-versions, Up: connector-j-versions 21.3.1.1 Java Versions Supported ................................ The following table summarizes Connector/J Java dependencies: Connector/J version Java RTE required JDK required (to build source code) 5.1 1.5.x, 1.6.x 1.6.x and 1.5.x 5.0 1.3.x, 1.4.x, 1.5.x, 1.4.2, 1.5.x, 1.6.x 1.6.x 3.1 1.2.x, 1.3.x, 1.4.x, 1.4.2, 1.5.x, 1.6.x 1.5.x, 1.6.x 3.0 1.2.x, 1.3.x, 1.4.x, 1.4.2, 1.5.x, 1.6.x 1.5.x, 1.6.x MySQL Connector/J does not support JDK-1.1.x or JDK-1.0.x. Because of the implementation of java.sql.Savepoint, Connector/J 3.1.0 and newer will not run on a Java runtime older than 1.4 unless the class verifier is turned off (by setting the `-Xverify:none' option to the Java runtime). This is because the class verifier will try to load the class definition for java.sql.Savepoint even though it is not accessed by the driver unless you actually use savepoint functionality. Caching functionality provided by Connector/J 3.1.0 or newer is also not available on JVMs older than 1.4.x, as it relies on java.util.LinkedHashMap which was first available in JDK-1.4.0. If you are building Connector/J from source code using the source distribution (see *Note connector-j-installing-source::) then you must use JDK 1.4.2 or newer to compile the Connector package. For Connector/J 5.1 you must have both JDK-1.6.x. and JDK-1.5.x installed to be able to build the source code.  File: manual.info, Node: connector-j-installing, Next: connector-j-examples, Prev: connector-j-versions, Up: connector-j 21.3.2 Connector/J Installation ------------------------------- * Menu: * connector-j-binary-installation:: Installing Connector/J from a Binary Distribution * connector-j-installing-classpath:: Installing the Driver and Configuring the `CLASSPATH' * connector-j-installing-upgrading:: Upgrading from an Older Version * connector-j-installing-source:: Installing from the Development Source Tree You can install the Connector/J package using either the binary or source distribution. The binary distribution provides the easiest method for installation; the source distribution enables you to customize your installation further. With either solution, you must manually add the Connector/J location to your Java `CLASSPATH'. If you are upgrading from a previous version, read the upgrade information before continuing. See *Note connector-j-installing-upgrading::. Connector/J is also available as part of the Maven project. More information, and the Connector/J JAR files can be found at the Maven repository (http://www.ibiblio.org/maven/).  File: manual.info, Node: connector-j-binary-installation, Next: connector-j-installing-classpath, Prev: connector-j-installing, Up: connector-j-installing 21.3.2.1 Installing Connector/J from a Binary Distribution .......................................................... The easiest method of installation is to use the binary distribution of the Connector/J package. The binary distribution is available either as a Tar/Gzip or Zip file which you must extract to a suitable location and then optionally make the information about the package available by changing your `CLASSPATH' (see *Note connector-j-installing-classpath::). MySQL Connector/J is distributed as a .zip or .tar.gz archive containing the sources, the class files, and the JAR archive named `mysql-connector-java-[VERSION]-bin.jar', and starting with Connector/J 3.1.8 a debug build of the driver in a file named `mysql-connector-java-[VERSION]-bin-g.jar'. Starting with Connector/J 3.1.9, the `.class' files that constitute the JAR files are only included as part of the driver JAR file. You should not use the debug build of the driver unless instructed to do so when reporting a problem or a bug, as it is not designed to be run in production environments, and will have adverse performance impact when used. The debug binary also depends on the Aspect/J runtime library, which is located in the `src/lib/aspectjrt.jar' file that comes with the Connector/J distribution. You will need to use the appropriate graphical or command-line utility to extract the distribution (for example, WinZip for the .zip archive, and `tar' for the .tar.gz archive). Because there are potentially long file names in the distribution, we use the GNU tar archive format. You will need to use GNU tar (or an application that understands the GNU tar archive format) to unpack the .tar.gz variant of the distribution.  File: manual.info, Node: connector-j-installing-classpath, Next: connector-j-installing-upgrading, Prev: connector-j-binary-installation, Up: connector-j-installing 21.3.2.2 Installing the Driver and Configuring the `CLASSPATH' .............................................................. Once you have extracted the distribution archive, you can install the driver by placing `mysql-connector-java-[version]-bin.jar 'in your classpath, either by adding the full path to it to your `CLASSPATH' environment variable, or by directly specifying it with the command line switch -cp when starting your JVM. If you are going to use the driver with the JDBC DriverManager, you would use `com.mysql.jdbc.Driver' as the class that implements java.sql.Driver. You can set the `CLASSPATH' environment variable under UNIX, Linux or Mac OS X either locally for a user within their `.profile', `.login' or other login file. You can also set it globally by editing the global `/etc/profile' file. For example, under a C shell (csh, tcsh) you would add the Connector/J driver to your `CLASSPATH' using the following: shell> setenv CLASSPATH /path/mysql-connector-java-[ver]-bin.jar:$CLASSPATH Or with a Bourne-compatible shell (sh, ksh, bash): shell> export set CLASSPATH=/path/mysql-connector-java-[ver]-bin.jar:$CLASSPATH Within Windows 2000, Windows XP, Windows Server 2003 and Windows Vista, you must set the environment variable through the System Control Panel. If you want to use MySQL Connector/J with an application server such as GlassFish, Tomcat or JBoss, you will have to read your vendor's documentation for more information on how to configure third-party class libraries, as most application servers ignore the `CLASSPATH' environment variable. For configuration examples for some J2EE application servers, see *Note connector-j-usagenotes-j2ee::. However, the authoritative source for JDBC connection pool configuration information for your particular application server is the documentation for that application server. If you are developing servlets or JSPs, and your application server is J2EE-compliant, you can put the driver's .jar file in the WEB-INF/lib subdirectory of your webapp, as this is a standard location for third party class libraries in J2EE web applications. You can also use the MysqlDataSource or MysqlConnectionPoolDataSource classes in the `com.mysql.jdbc.jdbc2.optional' package, if your J2EE application server supports or requires them. Starting with Connector/J 5.0.0, the `javax.sql.XADataSource' interface is implemented using the `com.mysql.jdbc.jdbc2.optional.MysqlXADataSource' class, which supports XA distributed transactions when used in combination with MySQL server version 5.0. The various MysqlDataSource classes support the following parameters (through standard set mutators): * user * password * serverName (see the previous section about fail-over hosts) * databaseName * port  File: manual.info, Node: connector-j-installing-upgrading, Next: connector-j-installing-source, Prev: connector-j-installing-classpath, Up: connector-j-installing 21.3.2.3 Upgrading from an Older Version ........................................ * Menu: * connector-j-installing-upgrading-3-0-to-3-1:: Upgrading from MySQL Connector/J 3.0 to 3.1 * connector-j-installing-upgrading-5-1:: Upgrading to MySQL Connector/J 5.1.x * connector-j-installing-upgrading-issues:: JDBC-Specific Issues When Upgrading to MySQL Server 4.1 or Newer We try to keep the upgrade process as easy as possible, however as is the case with any software, sometimes changes need to be made in new versions to support new features, improve existing functionality, or comply with new standards. This section has information about what users who are upgrading from one version of Connector/J to another (or to a new version of the MySQL server, with respect to JDBC functionality) should be aware of.  File: manual.info, Node: connector-j-installing-upgrading-3-0-to-3-1, Next: connector-j-installing-upgrading-5-1, Prev: connector-j-installing-upgrading, Up: connector-j-installing-upgrading 21.3.2.4 Upgrading from MySQL Connector/J 3.0 to 3.1 .................................................... Connector/J 3.1 is designed to be backward-compatible with Connector/J 3.0 as much as possible. Major changes are isolated to new functionality exposed in MySQL-4.1 and newer, which includes Unicode character sets, server-side prepared statements, SQLState codes returned in error messages by the server and various performance enhancements that can be enabled or disabled using configuration properties. * *Unicode Character Sets*: See the next section, as well as *Note charset::, for information on this new feature of MySQL. If you have something misconfigured, it will usually show up as an error with a message similar to `Illegal mix of collations'. * *Server-side Prepared Statements*: Connector/J 3.1 will automatically detect and use server-side prepared statements when they are available (MySQL server version 4.1.0 and newer). Starting with version 3.1.7, the driver scans SQL you are preparing using all variants of `Connection.prepareStatement()' to determine if it is a supported type of statement to prepare on the server side, and if it is not supported by the server, it instead prepares it as a client-side emulated prepared statement. You can disable this feature by passing emulateUnsupportedPstmts=false in your JDBC URL. If your application encounters issues with server-side prepared statements, you can revert to the older client-side emulated prepared statement code that is still presently used for MySQL servers older than 4.1.0 with the connection property useServerPrepStmts=false * *Datetimes* with all-zero components (`0000-00-00 ...'): These values can not be represented reliably in Java. Connector/J 3.0.x always converted them to `NULL' when being read from a ResultSet. Connector/J 3.1 throws an exception by default when these values are encountered as this is the most correct behavior according to the JDBC and SQL standards. This behavior can be modified using the zeroDateTimeBehavior configuration property. The permissible values are: * `exception' (the default), which throws an SQLException with an SQLState of `S1009'. * `convertToNull', which returns `NULL' instead of the date. * `round', which rounds the date to the nearest closest value which is `0001-01-01'. Starting with Connector/J 3.1.7, `ResultSet.getString()' can be decoupled from this behavior using noDatetimeStringSync=true (the default value is `false') so that you can retrieve the unaltered all-zero value as a String. It should be noted that this also precludes using any time zone conversions, therefore the driver will not allow you to enable noDatetimeStringSync and useTimezone at the same time. * *New SQLState Codes*: Connector/J 3.1 uses SQL:1999 SQLState codes returned by the MySQL server (if supported), which are different from the legacy X/Open state codes that Connector/J 3.0 uses. If connected to a MySQL server older than MySQL-4.1.0 (the oldest version to return SQLStates as part of the error code), the driver will use a built-in mapping. You can revert to the old mapping by using the configuration property useSqlStateCodes=false. * *`ResultSet.getString()'*: Calling `ResultSet.getString()' on a *Note `BLOB': blob. column will now return the address of the `byte[]' array that represents it, instead of a `String' representation of the *Note `BLOB': blob. *Note `BLOB': blob. values have no character set, so they cannot be converted to `java.lang.String's without data loss or corruption. To store strings in MySQL with LOB behavior, use one of the *Note `TEXT': blob. types, which the driver will treat as a `java.sql.Clob'. * *Debug builds*: Starting with Connector/J 3.1.8 a debug build of the driver in a file named `mysql-connector-java-[VERSION]-bin-g.jar' is shipped alongside the normal binary jar file that is named `mysql-connector-java-[VERSION]-bin.jar'. Starting with Connector/J 3.1.9, we do not ship the .class files unbundled, they are only available in the JAR archives that ship with the driver. You should not use the debug build of the driver unless instructed to do so when reporting a problem or bug, as it is not designed to be run in production environments, and will have adverse performance impact when used. The debug binary also depends on the Aspect/J runtime library, which is located in the `src/lib/aspectjrt.jar' file that comes with the Connector/J distribution.  File: manual.info, Node: connector-j-installing-upgrading-5-1, Next: connector-j-installing-upgrading-issues, Prev: connector-j-installing-upgrading-3-0-to-3-1, Up: connector-j-installing-upgrading 21.3.2.5 Upgrading to MySQL Connector/J 5.1.x ............................................. * In Connector/J 5.0.x and earlier, the alias for a table in a *Note `SELECT': select. statement is returned when accessing the result set metadata using `ResultSetMetaData.getColumnName()'. This behavior however is not JDBC compliant, and in Connector/J 5.1 this behavior was changed so that the original table name, rather than the alias, is returned. The JDBC-compliant behavior is designed to let API users reconstruct the DML statement based on the metadata within `ResultSet' and `ResultSetMetaData'. You can get the alias for a column in a result set by calling `ResultSetMetaData.getColumnLabel()'. If you want to use the old noncompliant behavior with `ResultSetMetaData.getColumnName()', use the `useOldAliasMetadataBehavior' option and set the value to `true'. In Connector/J 5.0.x the default value of `useOldAliasMetadataBehavior' was true, but in Connector/J 5.1 this was changed to a default value of false.  File: manual.info, Node: connector-j-installing-upgrading-issues, Prev: connector-j-installing-upgrading-5-1, Up: connector-j-installing-upgrading 21.3.2.6 JDBC-Specific Issues When Upgrading to MySQL Server 4.1 or Newer ......................................................................... * _Using the UTF-8 Character Encoding_ - Prior to MySQL server version 4.1, the UTF-8 character encoding was not supported by the server, however the JDBC driver could use it, allowing storage of multiple character sets in latin1 tables on the server. Starting with MySQL-4.1, this functionality is deprecated. If you have applications that rely on this functionality, and can not upgrade them to use the official Unicode character support in MySQL server version 4.1 or newer, you should add the following property to your connection URL: useOldUTF8Behavior=true * _Server-side Prepared Statements_ - Connector/J 3.1 will automatically detect and use server-side prepared statements when they are available (MySQL server version 4.1.0 and newer). If your application encounters issues with server-side prepared statements, you can revert to the older client-side emulated prepared statement code that is still presently used for MySQL servers older than 4.1.0 with the following connection property: useServerPrepStmts=false  File: manual.info, Node: connector-j-installing-source, Prev: connector-j-installing-upgrading, Up: connector-j-installing 21.3.2.7 Installing from the Development Source Tree .................................................... *Caution*: You should read this section only if you are interested in helping us test our new code. If you just want to get MySQL Connector/J up and running on your system, you should use a standard binary release distribution. To install MySQL Connector/J from the development source tree, make sure that you have the following prerequisites: * A Bazaar client, to check out the sources from our Launchpad repository (available from `http://bazaar-vcs.org/'). * Apache Ant version 1.7 or newer (available from `http://ant.apache.org/'). * JDK 1.4.2 or later. Although MySQL Connector/J can be be used with older JDKs, to compile it from source you must have at least JDK 1.4.2. If you are building Connector/J 5.1 you will need JDK 1.6.x and an older JDK such as JDK 1.5.x. You will then need to point your JAVA_HOME environment variable at the older installation. The source code repository for MySQL Connector/J is located on Launchpad at `https://code.launchpad.net/connectorj'. To check out and compile a specific branch of MySQL Connector/J, follow these steps: 1. Check out the latest code from the branch that you want with one of the following commands. To check out the latest development branch use: shell> bzr branch lp:connectorj This creates a `connectorj' subdirectory in the current directory that contains the latest sources for the requested branch. To check out the latest 5.1 code use: shell> bzr branch lp:connectorj/5.1 This will create a `5.1' subdirectory in the current directory containing the latest 5.1 code. 2. If you are building Connector/J 5.1 make sure that you have both JDK 1.6.x installed and an older JDK such as JDK 1.5.x. This is because Connector/J supports both JDBC 3.0 (which was prior to JDK 1.6.x) and JDBC 4.0. Set your JAVA_HOME environment variable to the path of the older JDK installation. 3. Change location to either the `connectorj' or `5.1' directory, depending on which branch you want to build, to make it your current working directory. For example: shell> cd connectorj 4. If you are building Connector/J 5.1 you need to edit the `build.xml' to reflect the location of your JDK 1.6.x installation. The lines that you need to change are: Alternatively, you can set the value of these property names through the Ant `-D' option. 5. Issue the following command to compile the driver and create a `.jar' file suitable for installation: shell> ant dist This creates a `build' directory in the current directory, where all build output will go. A directory is created in the `build' directory that includes the version number of the sources you are building from. This directory contains the sources, compiled `.class' files, and a `.jar' file suitable for deployment. For other possible targets, including ones that will create a fully packaged distribution, issue the following command: shell> ant -projecthelp 6. A newly created `.jar' file containing the JDBC driver will be placed in the directory `build/mysql-connector-java-[VERSION]'. Install the newly created JDBC driver as you would a binary `.jar' file that you download from MySQL by following the instructions in *Note connector-j-installing-classpath::. A package containing both the binary and source code for Connector/J 5.1 can also be found at the following location: Connector/J 5.1 Download (http://dev.mysql.com/downloads/connector/j/5.1.html)  File: manual.info, Node: connector-j-examples, Next: connector-j-reference, Prev: connector-j-installing, Up: connector-j 21.3.3 Connector/J Examples --------------------------- Examples of using Connector/J are located throughout this document, this section provides a summary and links to these examples. * *Note connector-j-examples-connection-drivermanager:: * *Note connector-j-examples-execute-select:: * *Note connector-j-examples-stored-procedure:: * *Note connector-j-examples-preparecall:: * *Note connector-j-examples-output-param:: * *Note connector-j-examples-callablestatement:: * *Note connector-j-examples-retrieving-results-params:: * *Note connector-j-examples-autoincrement-getgeneratedkeys:: * *Note connector-j-examples-autoincrement-select:: * *Note connector-j-examples-autoincrement-updateable-resultsets:: * *Note connector-j-examples-connectionpool-j2ee:: * *Note connector-j-examples-transaction-retry::  File: manual.info, Node: connector-j-reference, Next: connector-j-usagenotes, Prev: connector-j-examples, Up: connector-j 21.3.4 Connector/J (JDBC) Reference ----------------------------------- * Menu: * connector-j-reference-configuration-properties:: Driver/Datasource Class Names, URL Syntax and Configuration Properties for Connector/J * connector-j-reference-implementation-notes:: JDBC API Implementation Notes * connector-j-reference-type-conversions:: Java, JDBC and MySQL Types * connector-j-reference-charsets:: Using Character Sets and Unicode * connector-j-reference-using-ssl:: Connecting Securely Using SSL * connector-j-reference-replication-connection:: Using Master/Slave Replication with ReplicationConnection * connector-j-reference-error-sqlstates:: Mapping MySQL Error Numbers to SQLStates This section of the manual contains reference material for MySQL Connector/J, some of which is automatically generated during the Connector/J build process.  File: manual.info, Node: connector-j-reference-configuration-properties, Next: connector-j-reference-implementation-notes, Prev: connector-j-reference, Up: connector-j-reference 21.3.4.1 Driver/Datasource Class Names, URL Syntax and Configuration Properties for Connector/J ............................................................................................... The name of the class that implements java.sql.Driver in MySQL Connector/J is `com.mysql.jdbc.Driver'. The `org.gjt.mm.mysql.Driver' class name is also usable to remain backward-compatible with MM.MySQL. You should use this class name when registering the driver, or when otherwise configuring software to use MySQL Connector/J. The JDBC URL format for MySQL Connector/J is as follows, with items in square brackets ([, ]) being optional: jdbc:mysql://[host][,failoverhost...][:port]/[database] » [?propertyName1][=propertyValue1][&propertyName2][=propertyValue2]... If the host name is not specified, it defaults to 127.0.0.1. If the port is not specified, it defaults to 3306, the default port number for MySQL servers. jdbc:mysql://[host:port],[host:port].../[database] » [?propertyName1][=propertyValue1][&propertyName2][=propertyValue2]... If the database is not specified, the connection will be made with no default database. In this case, you will need to either call the `setCatalog()' method on the Connection instance or fully specify table names using the database name (that is, `SELECT dbname.tablename.colname FROM dbname.tablename...') in your SQL. Not specifying the database to use upon connection is generally only useful when building tools that work with multiple databases, such as GUI database managers. *Note*: JDBC clients should never employ the `USE database' statement to specify the desired database, they should always use the `Connection.setCatalog()' method instead. MySQL Connector/J has fail-over support. This enables the driver to fail-over to any number of slave hosts and still perform read-only queries. Fail-over only happens when the connection is in an `autoCommit(true)' state, because fail-over can not happen reliably when a transaction is in progress. Most application servers and connection pools set `autoCommit' to `true' at the end of every transaction/connection use. The fail-over functionality has the following behavior: * If the URL property autoReconnect is false: Failover only happens at connection initialization, and failback occurs when the driver determines that the first host has become available again. * If the URL property autoReconnect is true: Failover happens when the driver determines that the connection has failed (before _every_ query), and falls back to the first host when it determines that the host has become available again (after `queriesBeforeRetryMaster' queries have been issued). In either case, whenever you are connected to a "failed-over" server, the connection will be set to read-only state, so queries that would modify data will have exceptions thrown (the query will *never* be processed by the MySQL server). Configuration properties define how Connector/J will make a connection to a MySQL server. Unless otherwise noted, properties can be set for a DataSource object or for a Connection object. Configuration Properties can be set in one of the following ways: * Using the set*() methods on MySQL implementations of java.sql.DataSource (which is the preferred method when using implementations of java.sql.DataSource): * com.mysql.jdbc.jdbc2.optional.MysqlDataSource * com.mysql.jdbc.jdbc2.optional.MysqlConnectionPoolDataSource * As a key/value pair in the java.util.Properties instance passed to `DriverManager.getConnection()' or `Driver.connect()' * As a JDBC URL parameter in the URL given to `java.sql.DriverManager.getConnection()', `java.sql.Driver.connect()' or the MySQL implementations of the `javax.sql.DataSource' `setURL()' method. *Note*: If the mechanism you use to configure a JDBC URL is XML-based, you will need to use the XML character literal & to separate configuration parameters, as the ampersand is a reserved character for XML. The properties are listed in the following tables. Connection/Authentication * Property Name * * Definition * * * Default Since Value * Version * user The user to connect as all versions password The password to use when connecting all versions socketFactory The name of the class that the com.mysql.jdbc.StandardSocketFactory3.0.3 driver should use for creating socket connections to the server. This class must implement the interface 'com.mysql.jdbc.SocketFactory' and have public no-args constructor. connectTimeout Timeout for socket connect (in 0 3.0.1 milliseconds), with 0 being no timeout. Only works on JDK-1.4 or newer. Defaults to '0'. socketTimeout Timeout on network socket 0 3.0.1 operations (0, the default means no timeout). connectionLifecycleInterceptorsA comma-delimited list of classes 5.1.4 that implement "com.mysql.jdbc.ConnectionLifecycleInterceptor" that should notified of connection lifecycle events (creation, destruction, commit, rollback, setCatalog and setAutoCommit) and potentially alter the execution of these commands. ConnectionLifecycleInterceptors are "stackable", more than one interceptor may be specified via the configuration property as a comma-delimited list, with the interceptors executed in order from left to right. useConfigs Load the comma-delimited list of 3.1.5 configuration properties before parsing the URL or applying user-specified properties. These configurations are explained in the 'Configurations' of the documentation. interactiveClient Set the CLIENT_INTERACTIVE flag, false 3.1.0 which tells MySQL to timeout connections based on INTERACTIVE_TIMEOUT instead of WAIT_TIMEOUT localSocketAddress Hostname or IP address given to 5.0.5 explicitly configure the interface that the driver will bind the client side of the TCP/IP connection to when connecting. propertiesTransform An implementation of 3.1.4 com.mysql.jdbc.ConnectionPropertiesTransform that the driver will use to modify URL properties passed to the driver before attempting a connection useCompression Use zlib compression when false 3.0.17 communicating with the server (true/false)? Defaults to 'false'. Networking * Property Name * * Definition * * * Default Since Value * Version * maxAllowedPacket Maximum allowed packet size to send -1 5.1.8 to server. If not set, the value of system variable 'max_allowed_packet' will be used to initialize this upon connecting. This value will not take effect if set larger than the value of 'max_allowed_packet'. tcpKeepAlive If connecting using TCP/IP, should true 5.0.7 the driver set SO_KEEPALIVE? tcpNoDelay If connecting using TCP/IP, should true 5.0.7 the driver set SO_TCP_NODELAY (disabling the Nagle Algorithm)? tcpRcvBuf If connecting using TCP/IP, should 0 5.0.7 the driver set SO_RCV_BUF to the given value? The default value of '0', means use the platform default value for this property) tcpSndBuf If connecting using TCP/IP, shuold 0 5.0.7 the driver set SO_SND_BUF to the given value? The default value of '0', means use the platform default value for this property) tcpTrafficClass If connecting using TCP/IP, should 0 5.0.7 the driver set traffic class or type-of-service fields ?See the documentation for java.net.Socket.setTrafficClass() for more information. High Availability and Clustering * Property Name * * Definition * * * Default Since Value * Version * autoReconnect Should the driver try to false 1.1 re-establish stale and/or dead connections? If enabled the driver will throw an exception for a queries issued on a stale or dead connection, which belong to the current transaction, but will attempt reconnect before the next query issued on the connection in a new transaction. The use of this feature is not recommended, because it has side effects related to session state and data consistency when applications don't handle SQLExceptions properly, and is only designed to be used when you are unable to configure your application to handle SQLExceptions resulting from dead and stale connections properly. Alternatively, investigate setting the MySQL server variable "wait_timeout" to some high value rather than the default of 8 hours. autoReconnectForPools Use a reconnection strategy false 3.1.3 appropriate for connection pools (defaults to 'false') failOverReadOnly When failing over in autoReconnect true 3.0.12 mode, should the connection be set to 'read-only'? maxReconnects Maximum number of reconnects to 3 1.1 attempt if autoReconnect is true, default is '3'. reconnectAtTxEnd If autoReconnect is set to true, false 3.0.10 should the driver attempt reconnections at the end of every transaction? retriesAllDown When using loadbalancing, the 120 5.1.6 number of times the driver should cycle through available hosts, attempting to connect. Between cycles, the driver will pause for 250ms if no servers are available. initialTimeout If autoReconnect is enabled, the 2 1.1 initial time to wait between re-connect attempts (in seconds, defaults to '2'). roundRobinLoadBalance When autoReconnect is enabled, and false 3.1.2 failoverReadonly is false, should we pick hosts to connect to on a round-robin basis? queriesBeforeRetryMasterNumber of queries to issue before 50 3.0.2 falling back to master when failed over (when using multi-host failover). Whichever condition is met first, 'queriesBeforeRetryMaster' or 'secondsBeforeRetryMaster' will cause an attempt to be made to reconnect to the master. Defaults to 50. secondsBeforeRetryMasterHow long should the driver wait, 30 3.0.2 when failed over, before attempting selfDestructOnPingMaxOperations=If set to a non-zero value, the 0 5.1.6 driver will report close the connection and report failure when Connection.ping() or Connection.isValid(int) is called if the connnection's count of commands sent to the server exceeds this value. selfDestructOnPingSecondsLifetimeIf set to a non-zero value, the 0 5.1.6 driver will report close the connection and report failure when Connection.ping() or Connection.isValid(int) is called if the connnection's lifetime exceeds this value. resourceId A globally unique name that 5.0.1 identifies the resource that this datasource or connection is connected to, used for XAResource.isSameRM() when the driver can't determine this value based on hostnames used in the URL Security * Property Name * * Definition * * * Default Since Value * Version * allowMultiQueries Allow the use of ';' to delimit false 3.1.1 multiple queries during one statement (true/false), defaults to 'false' useSSL Use SSL when communicating with the false 3.0.2 server (true/false), defaults to 'false' requireSSL Require SSL connection if false 3.1.0 useSSL=true? (defaults to 'false'). verifyServerCertificateIf "useSSL" is set to "true", true 5.1.6 should the driver verify the server's certificate? When using this feature, the keystore parameters should be specified by the "clientCertificateKeyStore*" properties, rather than system properties. clientCertificateKeyStoreUrlURL to the client certificate 5.1.0 KeyStore (if not specified, use defaults) clientCertificateKeyStoreTypeKeyStore type for client JKS 5.1.0 certificates (NULL or empty means use the default, which is "JKS". Standard keystore types supported by the JVM are "JKS" and "PKCS12", your environment may have more available depending on what security products are installed and available to the JVM. clientCertificateKeyStorePasswordPassword for the client 5.1.0 certificates KeyStore trustCertificateKeyStoreUrlURL to the trusted root certificate 5.1.0 KeyStore (if not specified, use defaults) trustCertificateKeyStoreTypeKeyStore type for trusted root JKS 5.1.0 certificates (NULL or empty means use the default, which is "JKS". Standard keystore types supported by the JVM are "JKS" and "PKCS12", your environment may have more available depending on what security products are installed and available to the JVM. trustCertificateKeyStorePasswordPassword for the trusted root 5.1.0 certificates KeyStore allowLoadLocalInfile Should the driver allow use of true 3.0.3 'LOAD DATA LOCAL INFILE...' (defaults to 'true'). allowUrlInLocalInfile Should the driver allow URLs in false 3.1.4 'LOAD DATA LOCAL INFILE' statements? paranoid Take measures to prevent exposure false 3.0.1 sensitive information in error messages and clear data structures holding sensitive data when possible? (defaults to 'false') passwordCharacterEncodingWhat character encoding is used for 5.1.7 passwords? Leaving this set to the default value (null), uses the platform character set, which works for ISO8859_1 (i.e. "latin1") passwords. For passwords in other character encodings, the encoding will have to be specified with this property, as it's not possible for the driver to auto-detect this. Performance Extensions * Property Name * * Definition * * * Default Since Value * Version * callableStmtCacheSize If 'cacheCallableStmts' is enabled, 100 3.1.2 how many callable statements should be cached? metadataCacheSize The number of queries to cache 50 3.1.1 ResultSetMetadata for if cacheResultSetMetaData is set to 'true' (default 50) useLocalSessionState Should the driver refer to the false 3.1.7 internal values of autocommit and transaction isolation that are set by Connection.setAutoCommit() and Connection.setTransactionIsolation() and transaction state as maintained by the protocol, rather than querying the database or blindly sending commands to the database for commit() or rollback() method calls? useLocalTransactionStateShould the driver use the false 5.1.7 in-transaction state provided by the MySQL protocol to determine if a commit() or rollback() should actually be sent to the database? prepStmtCacheSize If prepared statement caching is 25 3.0.10 enabled, how many prepared statements should be cached? prepStmtCacheSqlLimit If prepared statement caching is 256 3.0.10 enabled, what's the largest SQL the driver will cache the parsing for? alwaysSendSetIsolation Should the driver always true 3.1.7 communicate with the database when Connection.setTransactionIsolation() is called? If set to false, the driver will only communicate with the database when the requested transaction isolation is different than the whichever is newer, the last value that was set via Connection.setTransactionIsolation(), or the value that was read from the server when the connection was established. maintainTimeStats Should the driver maintain various true 3.1.9 internal timers to enable idle time calculations as well as more verbose error messages when the connection to the server fails? Setting this property to false removes at least two calls to System.getCurrentTimeMillis() per query. useCursorFetch If connected to MySQL > 5.0.2, and false 5.0.0 setFetchSize() > 0 on a statement, should that statement use cursor-based fetching to retrieve rows? blobSendChunkSize Chunk to use when sending 1048576 3.1.9 BLOB/CLOBs via ServerPreparedStatements cacheCallableStmts Should the driver cache the parsing false 3.1.2 stage of CallableStatements cachePrepStmts Should the driver cache the parsing false 3.0.10 stage of PreparedStatements of client-side prepared statements, the "check" for suitability of server-side prepared and server-side prepared statements themselves? cacheResultSetMetadata Should the driver cache false 3.1.1 ResultSetMetaData for Statements and PreparedStatements? (Req. JDK-1.4+, true/false, default 'false') cacheServerConfigurationShould the driver cache the results false 3.1.5 of 'SHOW VARIABLES' and 'SHOW COLLATION' on a per-URL basis? defaultFetchSize The driver will call 0 3.1.9 setFetchSize(n) with this value on all newly-created Statements dontTrackOpenResources The JDBC specification requires the false 3.1.7 driver to automatically track and close resources, however if your application doesn't do a good job of explicitly calling close() on statements or result sets, this can cause memory leakage. Setting this property to true relaxes this constraint, and can be more memory efficient for some applications. dynamicCalendars Should the driver retrieve the false 3.1.5 default calendar when required, or cache it per connection/session? elideSetAutoCommits If using MySQL-4.1 or newer, should false 3.1.3 the driver only issue 'set autocommit=n' queries when the server's state doesn't match the requested state by Connection.setAutoCommit(boolean)? enableQueryTimeouts When enabled, query timeouts set true 5.0.6 via Statement.setQueryTimeout() use a shared java.util.Timer instance for scheduling. Even if the timeout doesn't expire before the query is processed, there will be memory used by the TimerTask for the given timeout which won't be reclaimed until the time the timeout would have expired if it hadn't been cancelled by the driver. High-load environments might want to consider disabling this functionality. holdResultsOpenOverStatementCloseShould the driver leave the result false 3.1.7 sets open on Statement.close() (enabling violates JDBC specification) largeRowSizeThreshold What size result set row should the 2048 5.1.1 JDBC driver consider "large", and thus use a more memory-efficient way of representing the row internally? loadBalanceStrategy If using a load-balanced connection random 5.0.6 to connect to SQL nodes in a MySQL Cluster/NDB configuration (by using the URL prefix "jdbc:mysql:loadbalance://"), which load balancing algorithm should the driver use: (1) "random" - the driver will pick a random host for each request. This tends to work better than round-robin, as the randomness will somewhat account for spreading loads where requests vary in response time, while round-robin can sometimes lead to overloaded nodes if there are variations in response times across the workload. (2) "bestResponseTime" - the driver will route the request to the host that had the best response time for the previous transaction. locatorFetchBufferSize If 'emulateLocators' is configured 1048576 3.2.1 to 'true', what size buffer should be used when fetching BLOB data for getBinaryInputStream? rewriteBatchedStatementsShould the driver use multiqueries false 3.1.13 (irregardless of the setting of "allowMultiQueries") as well as rewriting of prepared statements for INSERT into multi-value inserts when executeBatch() is called? Notice that this has the potential for SQL injection if using plain java.sql.Statements and your code doesn't sanitize input correctly. Notice that for prepared statements, server-side prepared statements can not currently take advantage of this rewrite option, and that if you don't specify stream lengths when using PreparedStatement.set*Stream(), the driver won't be able to determine the optimum number of parameters per batch and you might receive an error from the driver that the resultant packet is too large. Statement.getGeneratedKeys() for these rewritten statements only works when the entire batch includes INSERT statements. useDirectRowUnpack Use newer result set row unpacking true 5.1.1 code that skips a copy from network buffers to a MySQL packet instance and instead reads directly into the result set row data buffers. useDynamicCharsetInfo Should the driver use a true 5.0.6 per-connection cache of character set information queried from the server when necessary, or use a built-in static mapping that is more efficient, but isn't aware of custom character sets or character sets implemented after the release of the JDBC driver? useFastDateParsing Use internal true 5.0.5 String->Date/Time/Timestamp conversion routines to avoid excessive object creation? useFastIntParsing Use internal String->Integer true 3.1.4 conversion routines to avoid excessive object creation? useJvmCharsetConvertersAlways use the character encoding false 5.0.1 routines built into the JVM, rather than using lookup tables for single-byte character sets? useReadAheadInput Use newer, optimized non-blocking, true 3.1.5 buffered input stream when reading from the server? Debugging/Profiling * Property Name * * Definition * * * Default Since Value * Version * logger The name of a class that implements com.mysql.jdbc.log.StandardLogger3.1.1 "com.mysql.jdbc.log.Log" that will be used to log messages to. (default is "com.mysql.jdbc.log.StandardLogger", which logs to STDERR) gatherPerfMetrics Should the driver gather false 3.1.2 performance metrics, and report them via the configured logger every 'reportMetricsIntervalMillis' milliseconds? profileSQL Trace queries and their false 3.1.0 execution/fetch times to the configured logger (true/false) defaults to 'false' profileSql Deprecated, use 'profileSQL' 2.0.14 instead. Trace queries and their execution/fetch times on STDERR (true/false) defaults to 'false' reportMetricsIntervalMillisIf 'gatherPerfMetrics' is enabled, 30000 3.1.2 how often should they be logged (in ms)? maxQuerySizeToLog Controls the maximum length/size of 2048 3.1.3 a query that will get logged when profiling or tracing packetDebugBufferSize The maximum number of packets to 20 3.1.3 retain when 'enablePacketDebug' is true slowQueryThresholdMillisIf 'logSlowQueries' is enabled, how 2000 3.1.2 long should a query (in ms) before it is logged as 'slow'? slowQueryThresholdNanosIf 'useNanosForElapsedTime' is set 0 5.0.7 to true, and this property is set to a non-zero value, the driver will use this threshold (in nanosecond units) to determine if a query was slow. useUsageAdvisor Should the driver issue 'usage' false 3.1.1 warnings advising proper and efficient usage of JDBC and MySQL Connector/J to the log (true/false, defaults to 'false')? autoGenerateTestcaseScriptShould the driver dump the SQL it false 3.1.9 is executing, including server-side prepared statements to STDERR? autoSlowLog Instead of using true 5.1.4 slowQueryThreshold* to determine if a query is slow enough to be logged, maintain statistics that allow the driver to determine queries that are outside the 99th percentile? clientInfoProvider The name of a class that implements com.mysql.jdbc.JDBC4CommentClientInfoProvider5.1.0 the com.mysql.jdbc.JDBC4ClientInfoProvider interface in order to support JDBC-4.0's Connection.get/setClientInfo() methods dumpMetadataOnColumnNotFoundShould the driver dump the false 3.1.13 field-level metadata of a result set into the exception message when ResultSet.findColumn() fails? dumpQueriesOnException Should the driver dump the contents false 3.1.3 of the query sent to the server in the message for SQLExceptions? enablePacketDebug When enabled, a ring-buffer of false 3.1.3 'packetDebugBufferSize' packets will be kept, and dumped when exceptions are thrown in key areas in the driver's code explainSlowQueries If 'logSlowQueries' is enabled, false 3.1.2 should the driver automatically issue an 'EXPLAIN' on the server and send the results to the configured log at a WARN level? includeInnodbStatusInDeadlockExceptionsInclude the output of "SHOW ENGINE false 5.0.7 INNODB STATUS" in exception messages when deadlock exceptions are detected? includeThreadDumpInDeadlockExceptionsInclude a current Java thread dump false 5.1.15 in exception messages when deadlock exceptions are detected? includeThreadNamesAsStatementCommentInclude the name of the current false 5.1.15 thread as a comment visible in "SHOW PROCESSLIST", or in Innodb deadlock dumps, useful in correlation with "includeInnodbStatusInDeadlockExceptions=true" and "includeThreadDumpInDeadlockExceptions=true". logSlowQueries Should queries that take longer false 3.1.2 than 'slowQueryThresholdMillis' be logged? logXaCommands Should the driver log XA commands false 5.0.5 sent by MysqlXaConnection to the server, at the DEBUG level of logging? profilerEventHandler Name of a class that implements the com.mysql.jdbc.profiler.LoggingProfilerEventHandler5.1.6 interface com.mysql.jdbc.profiler.ProfilerEventHandler that will be used to handle profiling/tracing events. resultSetSizeThreshold If the usage advisor is enabled, 100 5.0.5 how many rows should a result set contain before the driver warns that it is suspiciously large? traceProtocol Should trace-level network protocol false 3.1.2 be logged? useNanosForElapsedTime For profiling/debugging false 5.0.7 functionality that measures elapsed time, should the driver try to use nanoseconds resolution if available (JDK >= 1.5)? Miscellaneous * Property Name * * Definition * * * Default Since Value * Version * useUnicode Forces the driver to use Unicode true 1.1g character encodings. Should only be set to false either when the driver can't determine the character set mapping (in which case, specify the Java character encoding in the characterEncoding property), or you are trying to force the driver to use a character set that MySQL doesn't natively support. Should be 'true' for all versions of MySQL 4.1 or higher unless you are trying to emulate the character set handling support provided in MySQL 4.0. Value is true/false, defaults to 'true' characterEncoding If 'useUnicode' is set to true, 1.1g what Java character encoding should the driver use when dealing with strings? (defaults is to 'autodetect'). If the encoding cannot be determined, then an exception will be raised. characterSetResults Character set to tell the server to 3.0.13 return results as. connectionCollation If set, tells the server to use 3.0.13 this collation via 'set collation_connection' useBlobToStoreUTF8OutsideBMPTells the driver to treat false 5.1.3 [MEDIUM/LONG]BLOB columns as [LONG]VARCHAR columns holding text encoded in UTF-8 that has characters outside the BMP (4-byte encodings), which MySQL server can't handle natively. utf8OutsideBmpExcludedColumnNamePatternWhen "useBlobToStoreUTF8OutsideBMP" 5.1.3 is set to "true", column names matching the given regex will still be treated as BLOBs unless they match the regex specified for "utf8OutsideBmpIncludedColumnNamePattern". The regex must follow the patterns used for the java.util.regex package. utf8OutsideBmpIncludedColumnNamePatternUsed to specify exclusion rules to 5.1.3 "utf8OutsideBmpExcludedColumnNamePattern". The regex must follow the patterns used for the java.util.regex package. loadBalanceEnableJMX Enables JMX-based management of false 5.1.13 load-balanced connection groups, including live addition/removal of hosts from load-balancing pool. sessionVariables A comma-separated list of 3.1.8 name/value pairs to be sent as SET SESSION ... to the server when the driver connects. useColumnNamesInFindColumnPrior to JDBC-4.0, the JDBC false 5.1.7 specification had a bug related to what could be given as a "column name" to ResultSet methods like findColumn(), or getters that took a String property. JDBC-4.0 clarified "column name" to mean the label, as given in an "AS" clause and returned by ResultSetMetaData.getColumnLabel(), and if no AS clause, the column name. Setting this property to "true" will give behavior that is congruent to JDBC-3.0 and earlier versions of the JDBC specification, but which because of the specification bug could give unexpected results. This property is preferred over "useOldAliasMetadataBehavior" unless you need the specific behavior that it provides with respect to ResultSetMetadata. allowNanAndInf Should the driver allow NaN or +/- false 3.1.5 INF values in PreparedStatement.setDouble()? autoClosePStmtStreams Should the driver automatically false 3.1.12 call .close() on streams/readers passed as arguments via set*() methods? autoDeserialize Should the driver automatically false 3.1.5 detect and de-serialize objects stored in BLOB fields? blobsAreStrings Should the driver always treat false 5.0.8 BLOBs as Strings - specifically to work around dubious metadata returned by the server for GROUP BY clauses? capitalizeTypeNames Capitalize type names in true 2.0.7 DatabaseMetaData? (usually only useful when using WebObjects, true/false, defaults to 'false') clobCharacterEncoding The character encoding to use for 5.0.0 sending and retrieving TEXT, MEDIUMTEXT and LONGTEXT values instead of the configured connection characterEncoding clobberStreamingResultsThis will cause a 'streaming' false 3.0.9 ResultSet to be automatically closed, and any outstanding data still streaming from the server to be discarded if another query is executed before all the data has been read from the server. compensateOnDuplicateKeyUpdateCountsShould the driver compensate for false 5.1.7 the update counts of "ON DUPLICATE KEY" INSERT statements (2 = 1, 0 = 1) when using prepared statements? continueBatchOnError Should the driver continue true 3.0.3 processing batch commands if one statement fails. The JDBC spec allows either way (defaults to 'true'). createDatabaseIfNotExistCreates the database given in the false 3.1.9 URL if it doesn't yet exist. Assumes the configured user has permissions to create databases. emptyStringsConvertToZeroShould the driver allow conversions true 3.1.8 from empty string fields to numeric values of '0'? emulateLocators Should the driver emulate false 3.1.0 java.sql.Blobs with locators? With this feature enabled, the driver will delay loading the actual Blob data until the one of the retrieval methods (getInputStream(), getBytes(), and so forth) on the blob data stream has been accessed. For this to work, you must use a column alias with the value of the column to the actual name of the Blob. The feature also has the following restrictions: The SELECT that created the result set must reference only one table, the table must have a primary key; the SELECT must alias the original blob column name, specified as a string, to an alternate name; the SELECT must cover all columns that make up the primary key. emulateUnsupportedPstmtsShould the driver detect prepared true 3.1.7 statements that are not supported by the server, and replace them with client-side emulated versions? exceptionInterceptors Comma-delimited list of classes 5.1.8 that implement com.mysql.jdbc.ExceptionInterceptor. These classes will be instantiated one per Connection instance, and all SQLExceptions thrown by the driver will be allowed to be intercepted by these interceptors, in a chained fashion, with the first class listed as the head of the chain. functionsNeverReturnBlobsShould the driver always treat data false 5.0.8 from functions returning BLOBs as Strings - specifically to work around dubious metadata returned by the server for GROUP BY clauses? generateSimpleParameterMetadataShould the driver generate false 5.0.5 simplified parameter metadata for PreparedStatements when no metadata is available either because the server couldn't support preparing the statement, or server-side prepared statements are disabled? ignoreNonTxTables Ignore non-transactional table false 3.0.9 warning for rollback? (defaults to 'false'). jdbcCompliantTruncationThis sets whether Connector/J true 3.1.2 should throw java.sql.DataTruncation exceptions when data is truncated. This is required by the JDBC specification when connected to a server that supports warnings (MySQL 4.1.0 and newer). This property has no effect if the server sql-mode includes STRICT_TRANS_TABLES. Note that if STRICT_TRANS_TABLES is not set, it will be set as a result of using this connection string option. loadBalanceAutoCommitStatementRegexWhen load-balancing is enabled for 5.1.15 auto-commit statements (via loadBalanceAutoCommitStatementThreshold), the statement counter will only increment when the SQL matches the regular expression. By default, every statement issued matches. loadBalanceAutoCommitStatementThresholdWhen auto-commit is enabled, the 0 5.1.15 number of statements which should be executed before triggering load-balancing to rebalance. Default value of 0 causes load-balanced connections to only rebalance when exceptions are encountered, or auto-commit is disabled and transactions are explicitly committed or rolled back. loadBalanceBlacklistTimeoutTime in milliseconds between checks 0 5.1.0 of servers which are unavailable. loadBalanceConnectionGroupLogical group of load-balanced 5.1.13 connections within a classloader, used to manage different groups independently. If not specified, live management of load-balanced connections is disabled. loadBalanceExceptionCheckerFully-qualified class name of com.mysql.jdbc.StandardLoadBalanceExceptionChecker5.1.13 custom exception checker. The class must implement com.mysql.jdbc.LoadBalanceExceptionChecker interface, and is used to inspect SQLExceptions and determine whether they should trigger fail-over to another host in a load-balanced deployment. loadBalancePingTimeout Time in milliseconds to wait for 0 5.1.13 ping response from each of load-balanced physical connections when using load-balanced Connection. loadBalanceSQLExceptionSubclassFailoverComma-delimited list of 5.1.13 classes/interfaces used by default load-balanced exception checker to determine whether a given SQLException should trigger failover. The comparison is done using Class.isInstance(SQLException) using the thrown SQLException. loadBalanceSQLStateFailoverComma-delimited list of SQLState 5.1.13 codes used by default load-balanced exception checker to determine whether a given SQLException should trigger failover. The SQLState of a given SQLException is evaluated to determine whether it begins with any value in the comma-delimited list. loadBalanceValidateConnectionOnSwapServerShould the load-balanced Connection false 5.1.13 explicitly check whether the connection is live when swapping to a new physical connection at commit/rollback? maxRows The maximum number of rows to -1 all return (0, the default means return versions all rows). netTimeoutForStreamingResultsWhat value should the driver 600 5.1.0 automatically set the server setting 'net_write_timeout' to when the streaming result sets feature is in use? (value has unit of seconds, the value '0' means the driver will not try and adjust this value) noAccessToProcedureBodiesWhen determining procedure false 5.0.3 parameter types for CallableStatements, and the connected user can't access procedure bodies through "SHOW CREATE PROCEDURE" or select on mysql.proc should the driver instead create basic metadata (all parameters reported as IN VARCHARs, but allowing registerOutParameter() to be called on them anyway) instead of throwing an exception? noDatetimeStringSync Don't ensure that false 3.1.7 ResultSet.getDatetimeType().toString().equals(ResultSet.getString()) noTimezoneConversionForTimeTypeDon't convert TIME values using the false 5.0.0 server timezone if 'useTimezone'='true' nullCatalogMeansCurrentWhen DatabaseMetadataMethods ask true 3.1.8 for a 'catalog' parameter, does the value null mean use the current catalog? When nullCatalogMeansCurrent is true the current catalog will be used if the catalog parameter is null. If nullCatalogMeansCurrent is false and the catalog parameter is null then the catalog parameter is not used to restrict the catalog search. (This is not JDBC-compliant, but follows legacy behavior from earlier versions of the driver) nullNamePatternMatchesAllShould DatabaseMetaData methods true 3.1.8 that accept *pattern parameters treat null the same as '%' (this is not JDBC-compliant, however older versions of the driver accepted this departure from the specification) overrideSupportsIntegrityEnhancementFacilityShould the driver return "true" for false 3.1.12 DatabaseMetaData.supportsIntegrityEnhancementFacility() even if the database doesn't support it to workaround applications that require this method to return "true" to signal support of foreign keys, even though the SQL specification states that this facility contains much more than just foreign key support (one such application being OpenOffice)? padCharsWithSpace If a result set column has the CHAR false 5.0.6 type and the value does not fill the amount of characters specified in the DDL for the column, should the driver pad the remaining characters with space (for ANSI compliance)? pedantic Follow the JDBC spec to the letter. false 3.0.0 pinGlobalTxToPhysicalConnectionWhen using XAConnections, should false 5.0.1 the driver ensure that operations on a given XID are always routed to the same physical connection? This allows the XAConnection to support "XA START ... JOIN" after "XA END" has been called populateInsertRowWithDefaultValuesWhen using ResultSets that are false 5.0.5 CONCUR_UPDATABLE, should the driver pre-populate the "insert" row with default values from the DDL for the table used in the query so those values are immediately available for ResultSet accessors? This functionality requires a call to the database for metadata each time a result set of this type is created. If disabled (the default), the default values will be populated by the an internal call to refreshRow() which pulls back default values and/or values changed by triggers. processEscapeCodesForPrepStmtsShould the driver process escape true 3.1.12 codes in queries that are prepared? queryTimeoutKillsConnectionIf the timeout given in false 5.1.9 Statement.setQueryTimeout() expires, should the driver forcibly abort the Connection instead of attempting to abort the query? relaxAutoCommit If the version of MySQL the driver false 2.0.13 connects to does not support transactions, still allow calls to commit(), rollback() and setAutoCommit() (true/false, defaults to 'false')? retainStatementAfterResultSetCloseShould the driver retain the false 3.1.11 Statement reference in a ResultSet after ResultSet.close() has been called. This is not JDBC-compliant after JDBC-4.0. rollbackOnPooledClose Should the driver issue a true 3.0.15 rollback() when the logical connection in a pool is closed? runningCTS13 Enables workarounds for bugs in false 3.1.7 Sun's JDBC compliance testsuite version 1.3 serverTimezone Override detection/mapping of 3.0.2 timezone. Used when timezone from server doesn't map to Java timezone statementInterceptors A comma-delimited list of classes 5.1.1 that implement "com.mysql.jdbc.StatementInterceptor" that should be placed "in between" query execution to influence the results. StatementInterceptors are "chainable", the results returned by the "current" interceptor will be passed on to the next in in the chain, from left-to-right order, as specified in this property. strictFloatingPoint Used only in older versions of false 3.0.0 compliance test strictUpdates Should the driver do strict true 3.0.4 checking (all primary keys selected) of updatable result sets (true, false, defaults to 'true')? tinyInt1isBit Should the driver treat the true 3.0.16 datatype TINYINT(1) as the BIT type (because the server silently converts BIT -> TINYINT(1) when creating tables)? transformedBitIsBooleanIf the driver converts TINYINT(1) false 3.1.9 to a different type, should it use BOOLEAN instead of BIT for future compatibility with MySQL-5.0, as MySQL-5.0 has a BIT type? treatUtilDateAsTimestampShould the driver treat true 5.0.5 java.util.Date as a TIMESTAMP for the purposes of PreparedStatement.setObject()? ultraDevHack Create PreparedStatements for false 2.0.3 prepareCall() when required, because UltraDev is broken and issues a prepareCall() for _all_ statements? (true/false, defaults to 'false') useAffectedRows Don't set the CLIENT_FOUND_ROWS false 5.1.7 flag when connecting to the server (not JDBC-compliant, will break most applications that rely on "found" rows vs. "affected rows" for DML statements), but does cause "correct" update counts from "INSERT ... ON DUPLICATE KEY UPDATE" statements to be returned by the server. useGmtMillisForDatetimesConvert between session timezone false 3.1.12 and GMT before creating Date and Timestamp instances (value of "false" is legacy behavior, "true" leads to more JDBC-compliant behavior. useHostsInPrivileges Add '@hostname' to users in true 3.0.2 DatabaseMetaData.getColumn/TablePrivileges() (true/false), defaults to 'true'. useInformationSchema When connected to MySQL-5.0.7 or false 5.0.0 newer, should the driver use the INFORMATION_SCHEMA to derive information used by DatabaseMetaData? useJDBCCompliantTimezoneShiftShould the driver use false 5.0.0 JDBC-compliant rules when converting TIME/TIMESTAMP/DATETIME values' timezone information for those JDBC arguments which take a java.util.Calendar argument? (Notice that this option is exclusive of the "useTimezone=true" configuration option.) useLegacyDatetimeCode Use code for true 5.1.6 DATE/TIME/DATETIME/TIMESTAMP handling in result sets and statements that consistently handles timezone conversions from client to server and back again, or use the legacy code for these datatypes that has been in the driver for backwards-compatibility? useOldAliasMetadataBehaviorShould the driver use the legacy false 5.0.4 behavior for "AS" clauses on columns and tables, and only return aliases (if any) for ResultSetMetaData.getColumnName() or ResultSetMetaData.getTableName() rather than the original column/table name? In 5.0.x, the default value was true. useOldUTF8Behavior Use the UTF-8 behavior the driver false 3.1.6 did when communicating with 4.0 and older servers useOnlyServerErrorMessagesDon't prepend 'standard' SQLState true 3.0.15 error messages to error messages returned by the server. useSSPSCompatibleTimezoneShiftIf migrating from an environment false 5.0.5 that was using server-side prepared statements, and the configuration property "useJDBCCompliantTimeZoneShift" set to "true", use compatible behavior when not using server-side prepared statements when sending TIMESTAMP values to the MySQL server. useServerPrepStmts Use server-side prepared statements false 3.1.0 if the server supports them? useSqlStateCodes Use SQL Standard state codes true 3.1.3 instead of 'legacy' X/Open/SQL state codes (true/false), default is 'true' useStreamLengthsInPrepStmtsHonor stream length parameter in true 3.0.2 PreparedStatement/ResultSet.setXXXStream() method calls (true/false, defaults to 'true')? useTimezone Convert time/date types between false 3.0.2 client and server timezones (true/false, defaults to 'false')? useUnbufferedInput Don't use BufferedInputStream for true 3.0.11 reading data from the server yearIsDateType Should the JDBC driver treat the true 3.1.9 MySQL type "YEAR" as a java.sql.Date, or as a SHORT? zeroDateTimeBehavior What should happen when the driver exception3.1.4 encounters DATETIME values that are composed entirely of zeros (used by MySQL to represent invalid dates)? Valid values are "exception", "round" and "convertToNull". Connector/J also supports access to MySQL using named pipes on Windows NT/2000/XP using the NamedPipeSocketFactory as a plugin-socket factory using the socketFactory property. If you do not use a namedPipePath property, the default of '\\.\pipe\MySQL' will be used. If you use the `NamedPipeSocketFactory', the host name and port number values in the JDBC url will be ignored. You can enable this feature using: socketFactory=com.mysql.jdbc.NamedPipeSocketFactory Named pipes only work when connecting to a MySQL server on the same physical machine as the one the JDBC driver is being used on. In simple performance tests, it appears that named pipe access is between 30%-50% faster than the standard TCP/IP access. However, this varies per system, and named pipes are slower than TCP/IP in many Windows configurations. You can create your own socket factories by following the example code in com.mysql.jdbc.NamedPipeSocketFactory, or com.mysql.jdbc.StandardSocketFactory.  File: manual.info, Node: connector-j-reference-implementation-notes, Next: connector-j-reference-type-conversions, Prev: connector-j-reference-configuration-properties, Up: connector-j-reference 21.3.4.2 JDBC API Implementation Notes ...................................... MySQL Connector/J passes all of the tests in the publicly available version of Sun's JDBC compliance test suite. However, in many places the JDBC specification is vague about how certain functionality should be implemented, or the specification enables leeway in implementation. This section gives details on a interface-by-interface level about how certain implementation decisions may affect how you use MySQL Connector/J. * *Blob* Starting with Connector/J version 3.1.0, you can emulate Blobs with locators by adding the property 'emulateLocators=true' to your JDBC URL. Using this method, the driver will delay loading the actual Blob data until you retrieve the other data and then use retrieval methods (`getInputStream()', `getBytes()', and so forth) on the blob data stream. For this to work, you must use a column alias with the value of the column to the actual name of the Blob, for example: SELECT id, 'data' as blob_data from blobtable For this to work, you must also follow these rules: * The *Note `SELECT': select. must also reference only one table, the table must have a primary key. * The *Note `SELECT': select. must alias the original blob column name, specified as a string, to an alternate name. * The *Note `SELECT': select. must cover all columns that make up the primary key. The Blob implementation does not allow in-place modification (they are copies, as reported by the `DatabaseMetaData.locatorsUpdateCopies()' method). Because of this, you should use the corresponding `PreparedStatement.setBlob()' or `ResultSet.updateBlob()' (in the case of updatable result sets) methods to save changes back to the database. * *CallableStatement* Starting with Connector/J 3.1.1, stored procedures are supported when connecting to MySQL version 5.0 or newer using the CallableStatement interface. Currently, the `getParameterMetaData()' method of CallableStatement is not supported. * *Clob* The Clob implementation does not allow in-place modification (they are copies, as reported by the `DatabaseMetaData.locatorsUpdateCopies()' method). Because of this, you should use the `PreparedStatement.setClob()' method to save changes back to the database. The JDBC API does not have a `ResultSet.updateClob()' method. * *Connection* Unlike older versions of MM.MySQL the `isClosed()' method does not ping the server to determine if it is available. In accordance with the JDBC specification, it only returns true if `closed()' has been called on the connection. If you need to determine if the connection is still valid, you should issue a simple query, such as `SELECT 1'. The driver will throw an exception if the connection is no longer valid. * *DatabaseMetaData* Foreign Key information (`getImportedKeys()'/`getExportedKeys()' and `getCrossReference()') is only available from InnoDB tables. However, the driver uses *Note `SHOW CREATE TABLE': show-create-table. to retrieve this information, so when other storage engines support foreign keys, the driver will transparently support them as well. * *PreparedStatement* PreparedStatements are implemented by the driver, as MySQL does not have a prepared statement feature. Because of this, the driver does not implement `getParameterMetaData()' or `getMetaData()' as it would require the driver to have a complete SQL parser in the client. Starting with version 3.1.0 MySQL Connector/J, server-side prepared statements and binary-encoded result sets are used when the server supports them. Take care when using a server-side prepared statement with *large* parameters that are set using `setBinaryStream()', `setAsciiStream()', `setUnicodeStream()', `setBlob()', or `setClob()'. If you want to re-execute the statement with any large parameter changed to a nonlarge parameter, it is necessary to call `clearParameters()' and set all parameters again. The reason for this is as follows: * During both server-side prepared statements and client-side emulation, large data is exchanged only when `PreparedStatement.execute()' is called. * Once that has been done, the stream used to read the data on the client side is closed (as per the JDBC spec), and cannot be read from again. * If a parameter changes from large to nonlarge, the driver must reset the server-side state of the prepared statement to allow the parameter that is being changed to take the place of the prior large value. This removes all of the large data that has already been sent to the server, thus requiring the data to be re-sent, using the `setBinaryStream()', `setAsciiStream()', `setUnicodeStream()', `setBlob()' or `setClob()' method. Consequently, if you want to change the type of a parameter to a nonlarge one, you must call `clearParameters()' and set all parameters of the prepared statement again before it can be re-executed. * *ResultSet* By default, ResultSets are completely retrieved and stored in memory. In most cases this is the most efficient way to operate, and due to the design of the MySQL network protocol is easier to implement. If you are working with ResultSets that have a large number of rows or large values, and can not allocate heap space in your JVM for the memory required, you can tell the driver to stream the results back one row at a time. To enable this functionality, you need to create a Statement instance in the following manner: stmt = conn.createStatement(java.sql.ResultSet.TYPE_FORWARD_ONLY, java.sql.ResultSet.CONCUR_READ_ONLY); stmt.setFetchSize(Integer.MIN_VALUE); The combination of a forward-only, read-only result set, with a fetch size of `Integer.MIN_VALUE' serves as a signal to the driver to stream result sets row-by-row. After this any result sets created with the statement will be retrieved row-by-row. There are some caveats with this approach. You will have to read all of the rows in the result set (or close it) before you can issue any other queries on the connection, or an exception will be thrown. The earliest the locks these statements hold can be released (whether they be `MyISAM' table-level locks or row-level locks in some other storage engine such as `InnoDB') is when the statement completes. If the statement is within scope of a transaction, then locks are released when the transaction completes (which implies that the statement needs to complete first). As with most other databases, statements are not complete until all the results pending on the statement are read or the active result set for the statement is closed. Therefore, if using streaming results, you should process them as quickly as possible if you want to maintain concurrent access to the tables referenced by the statement producing the result set. * *ResultSetMetaData* The `isAutoIncrement()' method only works when using MySQL servers 4.0 and newer. * *Statement* When using versions of the JDBC driver earlier than 3.2.1, and connected to server versions earlier than 5.0.3, the `setFetchSize()' method has no effect, other than to toggle result set streaming as described above. Connector/J 5.0.0 and later include support for both `Statement.cancel()' and `Statement.setQueryTimeout()'. Both require MySQL 5.0.0 or newer server, and require a separate connection to issue the *Note `KILL QUERY': kill. statement. In the case of `setQueryTimeout()', the implementation creates an additional thread to handle the timeout functionality. *Note*: Failures to cancel the statement for `setQueryTimeout()' may manifest themselves as `RuntimeException' rather than failing silently, as there is currently no way to unblock the thread that is executing the query being cancelled due to timeout expiration and have it throw the exception instead. MySQL does not support SQL cursors, and the JDBC driver doesn't emulate them, so "setCursorName()" has no effect. Connector/J 5.1.3 and later include two additional methods: * `setLocalInfileInputStream()' sets an `InputStream' instance that will be used to send data to the MySQL server for a *Note `LOAD DATA LOCAL INFILE': load-data. statement rather than a `FileInputStream' or `URLInputStream' that represents the path given as an argument to the statement. This stream will be read to completion upon execution of a *Note `LOAD DATA LOCAL INFILE': load-data. statement, and will automatically be closed by the driver, so it needs to be reset before each call to `execute*()' that would cause the MySQL server to request data to fulfill the request for *Note `LOAD DATA LOCAL INFILE': load-data. If this value is set to `NULL', the driver will revert to using a `FileInputStream' or `URLInputStream' as required. * `getLocalInfileInputStream()' returns the `InputStream' instance that will be used to send data in response to a *Note `LOAD DATA LOCAL INFILE': load-data. statement. This method returns `NULL' if no such stream has been set using `setLocalInfileInputStream()'.  File: manual.info, Node: connector-j-reference-type-conversions, Next: connector-j-reference-charsets, Prev: connector-j-reference-implementation-notes, Up: connector-j-reference 21.3.4.3 Java, JDBC and MySQL Types ................................... MySQL Connector/J is flexible in the way it handles conversions between MySQL data types and Java data types. In general, any MySQL data type can be converted to a java.lang.String, and any numeric type can be converted to any of the Java numeric types, although round-off, overflow, or loss of precision may occur. Starting with Connector/J 3.1.0, the JDBC driver will issue warnings or throw DataTruncation exceptions as is required by the JDBC specification unless the connection was configured not to do so by using the property jdbcCompliantTruncation and setting it to `false'. The conversions that are always guaranteed to work are listed in the following table: Connection Properties - Miscellaneous These MySQL Data Types Can always be converted to these Java types `CHAR, VARCHAR, BLOB, TEXT, ENUM, `java.lang.String, and SET' java.io.InputStream, java.io.Reader, java.sql.Blob, java.sql.Clob' `FLOAT, REAL, DOUBLE PRECISION, `java.lang.String, java.lang.Short, NUMERIC, DECIMAL, TINYINT, java.lang.Integer, java.lang.Long, SMALLINT, MEDIUMINT, INTEGER, java.lang.Double, BIGINT' java.math.BigDecimal' `DATE, TIME, DATETIME, TIMESTAMP' `java.lang.String, java.sql.Date, java.sql.Timestamp' *Note*: Round-off, overflow or loss of precision may occur if you choose a Java numeric data type that has less precision or capacity than the MySQL data type you are converting to/from. The ResultSet.getObject() method uses the type conversions between MySQL and Java types, following the JDBC specification where appropriate. The value returned by ResultSetMetaData.GetColumnClassName() is also shown below. For more information on the `java.sql.Types' classes see Java 2 Platform Types (http://java.sun.com/j2se/1.4.2/docs/api/java/sql/Types.html). MySQL Types to Java Types for ResultSet.getObject() MySQL Type Name Return value of Returned as Java Class `GetColumnClassName' BIT(1) (new in BIT java.lang.Boolean MySQL-5.0) BIT( > 1) (new in BIT byte[] MySQL-5.0) TINYINT TINYINT java.lang.Boolean if the configuration property `tinyInt1isBit' is set to `true' (the default) and the storage size is 1, or java.lang.Integer if not. BOOL, BOOLEAN TINYINT See TINYINT, above as these are aliases for TINYINT(1), currently. SMALLINT[(M)] SMALLINT java.lang.Integer (regardless if [UNSIGNED] [UNSIGNED] UNSIGNED or not) MEDIUMINT[(M)] MEDIUMINT java.lang.Integer, if UNSIGNED [UNSIGNED] [UNSIGNED] java.lang.Long (C/J 3.1 and earlier), or java.lang.Integer for C/J 5.0 and later INT,INTEGER[(M)] INTEGER [UNSIGNED] java.lang.Integer, if UNSIGNED [UNSIGNED] java.lang.Long BIGINT[(M)] BIGINT [UNSIGNED] java.lang.Long, if UNSIGNED [UNSIGNED] java.math.BigInteger FLOAT[(M,D)] FLOAT java.lang.Float DOUBLE[(M,B)] DOUBLE java.lang.Double DECIMAL[(M[,D])] DECIMAL java.math.BigDecimal DATE DATE java.sql.Date DATETIME DATETIME java.sql.Timestamp TIMESTAMP[(M)] TIMESTAMP java.sql.Timestamp TIME TIME java.sql.Time YEAR[(2|4)] YEAR If `yearIsDateType' configuration property is set to false, then the returned object type is java.sql.Short. If set to true (the default) then an object of type java.sql.Date (with the date set to January 1st, at midnight). CHAR(M) CHAR java.lang.String (unless the character set for the column is BINARY, then byte[] is returned. VARCHAR(M) VARCHAR java.lang.String (unless the [BINARY] character set for the column is BINARY, then byte[] is returned. BINARY(M) BINARY byte[] VARBINARY(M) VARBINARY byte[] TINYBLOB TINYBLOB byte[] TINYTEXT VARCHAR java.lang.String BLOB BLOB byte[] TEXT VARCHAR java.lang.String MEDIUMBLOB MEDIUMBLOB byte[] MEDIUMTEXT VARCHAR java.lang.String LONGBLOB LONGBLOB byte[] LONGTEXT VARCHAR java.lang.String ENUM('value1','value2',...)CHAR java.lang.String SET('value1','value2',...)CHAR java.lang.String  File: manual.info, Node: connector-j-reference-charsets, Next: connector-j-reference-using-ssl, Prev: connector-j-reference-type-conversions, Up: connector-j-reference 21.3.4.4 Using Character Sets and Unicode ......................................... All strings sent from the JDBC driver to the server are converted automatically from native Java Unicode form to the client character encoding, including all queries sent using `Statement.execute()', `Statement.executeUpdate()', `Statement.executeQuery()' as well as all PreparedStatement and CallableStatement parameters with the exclusion of parameters set using `setBytes()', `setBinaryStream()', `setAsciiStream()', `setUnicodeStream()' and `setBlob()'. Prior to MySQL Server 4.1, Connector/J supported a single character encoding per connection, which could either be automatically detected from the server configuration, or could be configured by the user through the useUnicode and characterEncoding properties. Starting with MySQL Server 4.1, Connector/J supports a single character encoding between client and server, and any number of character encodings for data returned by the server to the client in ResultSets. The character encoding between client and server is automatically detected upon connection. The encoding used by the driver is specified on the server using the `character_set' system variable for server versions older than 4.1.0 and `character_set_server' for server versions 4.1.0 and newer. For more information, see *Note charset-server::. To override the automatically detected encoding on the client side, use the characterEncoding property in the URL used to connect to the server. When specifying character encodings on the client side, Java-style names should be used. The following table lists Java-style names for MySQL character sets: MySQL to Java Encoding Name Translations MySQL Character Set Name Java-Style Character Encoding Name ascii US-ASCII big5 Big5 gbk GBK sjis SJIS (or Cp932 or MS932 for MySQL Server < 4.1.11) cp932 Cp932 or MS932 (MySQL Server > 4.1.11) gb2312 EUC_CN ujis EUC_JP euckr EUC_KR latin1 Cp1252 latin2 ISO8859_2 greek ISO8859_7 hebrew ISO8859_8 cp866 Cp866 tis620 TIS620 cp1250 Cp1250 cp1251 Cp1251 cp1257 Cp1257 macroman MacRoman macce MacCentralEurope utf8 UTF-8 ucs2 UnicodeBig *Warning*: Do not issue the query 'set names' with Connector/J, as the driver will not detect that the character set has changed, and will continue to use the character set detected during the initial connection setup. To allow multiple character sets to be sent from the client, the UTF-8 encoding should be used, either by configuring `utf8' as the default server character set, or by configuring the JDBC driver to use UTF-8 through the characterEncoding property.  File: manual.info, Node: connector-j-reference-using-ssl, Next: connector-j-reference-replication-connection, Prev: connector-j-reference-charsets, Up: connector-j-reference 21.3.4.5 Connecting Securely Using SSL ...................................... SSL in MySQL Connector/J encrypts all data (other than the initial handshake) between the JDBC driver and the server. The performance penalty for enabling SSL is an increase in query processing time between 35% and 50%, depending on the size of the query, and the amount of data it returns. For SSL Support to work, you must have the following: * A JDK that includes JSSE (Java Secure Sockets Extension), like JDK-1.4.1 or newer. SSL does not currently work with a JDK that you can add JSSE to, like JDK-1.2.x or JDK-1.3.x due to the following JSSE bug: `http://developer.java.sun.com/developer/bugParade/bugs/4273544.html' * A MySQL server that supports SSL and has been compiled and configured to do so, which is MySQL-4.0.4 or later, see *Note secure-connections::, for more information. * A client certificate (covered later in this section) The system works through two Java truststore files, one file contains the certificate information for the server (`truststore' in the examples below). The other file contains the certificate for the client (`keystore' in the examples below). All Java truststore files are password protected by supplying a suitable password to the `keytool' when you create the files. You need the file names and associated passwords to create an SSL connection. You will first need to import the MySQL server CA Certificate into a Java truststore. A sample MySQL server CA Certificate is located in the `SSL' subdirectory of the MySQL source distribution. This is what SSL will use to determine if you are communicating with a secure MySQL server. Alternatively, use the CA Certificate that you have generated or been provided with by your SSL provider. To use Java's `keytool' to create a truststore in the current directory , and import the server's CA certificate (`cacert.pem'), you can do the following (assuming that `keytool' is in your path. The `keytool' should be located in the `bin' subdirectory of your JDK or JRE): shell> keytool -import -alias mysqlServerCACert \ -file cacert.pem -keystore truststore You will need to enter the password when prompted for the keystore file. Interaction with `keytool' will look like this: Enter keystore password: ********* Owner: EMAILADDRESS=walrus@example.com, CN=Walrus, O=MySQL AB, L=Orenburg, ST=Some-State, C=RU Issuer: EMAILADDRESS=walrus@example.com, CN=Walrus, O=MySQL AB, L=Orenburg, ST=Some-State, C=RU Serial number: 0 Valid from: Fri Aug 02 16:55:53 CDT 2002 until: Sat Aug 02 16:55:53 CDT 2003 Certificate fingerprints: MD5: 61:91:A0:F2:03:07:61:7A:81:38:66:DA:19:C4:8D:AB SHA1: 25:77:41:05:D5:AD:99:8C:14:8C:CA:68:9C:2F:B8:89:C3:34:4D:6C Trust this certificate? [no]: yes Certificate was added to keystore You then have two options, you can either import the client certificate that matches the CA certificate you just imported, or you can create a new client certificate. To import an existing certificate, the certificate should be in DER format. You can use `openssl' to convert an existing certificate into the new format. For example: shell> openssl x509 -outform DER -in client-cert.pem -out client.cert You now need to import the converted certificate into your keystore using `keytool': shell> keytool -import -file client.cert -keystore keystore -alias mysqlClientCertificate To generate your own client certificate, use `keytool' to create a suitable certificate and add it to the `keystore' file: shell> keytool -genkey -keyalg rsa \ -alias mysqlClientCertificate -keystore keystore Keytool will prompt you for the following information, and create a keystore named `keystore' in the current directory. You should respond with information that is appropriate for your situation: Enter keystore password: ********* What is your first and last name? [Unknown]: Matthews What is the name of your organizational unit? [Unknown]: Software Development What is the name of your organization? [Unknown]: MySQL AB What is the name of your City or Locality? [Unknown]: Flossmoor What is the name of your State or Province? [Unknown]: IL What is the two-letter country code for this unit? [Unknown]: US Is correct? [no]: y Enter key password for (RETURN if same as keystore password): Finally, to get JSSE to use the keystore and truststore that you have generated, you need to set the following system properties when you start your JVM, replacing path_to_keystore_file with the full path to the keystore file you created, path_to_truststore_file with the path to the truststore file you created, and using the appropriate password values for each property. You can do this either on the command line: -Djavax.net.ssl.keyStore=path_to_keystore_file -Djavax.net.ssl.keyStorePassword=password -Djavax.net.ssl.trustStore=path_to_truststore_file -Djavax.net.ssl.trustStorePassword=password Or you can set the values directly within the application: System.setProperty("javax.net.ssl.keyStore","path_to_keystore_file"); System.setProperty("javax.net.ssl.keyStorePassword","password"); System.setProperty("javax.net.ssl.trustStore","path_to_truststore_file"); System.setProperty("javax.net.ssl.trustStorePassword","password"); You will also need to set useSSL to `true' in your connection parameters for MySQL Connector/J, either by adding `useSSL=true' to your URL, or by setting the property useSSL to `true' in the java.util.Properties instance you pass to `DriverManager.getConnection()'. You can test that SSL is working by turning on JSSE debugging (as detailed below), and look for the following key events: ... *** ClientHello, v3.1 RandomCookie: GMT: 1018531834 bytes = { 199, 148, 180, 215, 74, 12, » 54, 244, 0, 168, 55, 103, 215, 64, 16, 138, 225, 190, 132, 153, 2, » 217, 219, 239, 202, 19, 121, 78 } Session ID: {} Cipher Suites: { 0, 5, 0, 4, 0, 9, 0, 10, 0, 18, 0, 19, 0, 3, 0, 17 } Compression Methods: { 0 } *** [write] MD5 and SHA1 hashes: len = 59 0000: 01 00 00 37 03 01 3D B6 90 FA C7 94 B4 D7 4A 0C ...7..=.......J. 0010: 36 F4 00 A8 37 67 D7 40 10 8A E1 BE 84 99 02 D9 6...7g.@........ 0020: DB EF CA 13 79 4E 00 00 10 00 05 00 04 00 09 00 ....yN.......... 0030: 0A 00 12 00 13 00 03 00 11 01 00 ........... main, WRITE: SSL v3.1 Handshake, length = 59 main, READ: SSL v3.1 Handshake, length = 74 *** ServerHello, v3.1 RandomCookie: GMT: 1018577560 bytes = { 116, 50, 4, 103, 25, 100, 58, » 202, 79, 185, 178, 100, 215, 66, 254, 21, 83, 187, 190, 42, 170, 3, » 132, 110, 82, 148, 160, 92 } Session ID: {163, 227, 84, 53, 81, 127, 252, 254, 178, 179, 68, 63, » 182, 158, 30, 11, 150, 79, 170, 76, 255, 92, 15, 226, 24, 17, 177, » 219, 158, 177, 187, 143} Cipher Suite: { 0, 5 } Compression Method: 0 *** %% Created: [Session-1, SSL_RSA_WITH_RC4_128_SHA] ** SSL_RSA_WITH_RC4_128_SHA [read] MD5 and SHA1 hashes: len = 74 0000: 02 00 00 46 03 01 3D B6 43 98 74 32 04 67 19 64 ...F..=.C.t2.g.d 0010: 3A CA 4F B9 B2 64 D7 42 FE 15 53 BB BE 2A AA 03 :.O..d.B..S..*.. 0020: 84 6E 52 94 A0 5C 20 A3 E3 54 35 51 7F FC FE B2 .nR..\ ..T5Q.... 0030: B3 44 3F B6 9E 1E 0B 96 4F AA 4C FF 5C 0F E2 18 .D?.....O.L.\... 0040: 11 B1 DB 9E B1 BB 8F 00 05 00 .......... main, READ: SSL v3.1 Handshake, length = 1712 ... JSSE provides debugging (to STDOUT) when you set the following system property: `-Djavax.net.debug=all' This will tell you what keystores and truststores are being used, as well as what is going on during the SSL handshake and certificate exchange. It will be helpful when trying to determine what is not working when trying to get an SSL connection to happen.  File: manual.info, Node: connector-j-reference-replication-connection, Next: connector-j-reference-error-sqlstates, Prev: connector-j-reference-using-ssl, Up: connector-j-reference 21.3.4.6 Using Master/Slave Replication with ReplicationConnection .................................................................. Starting with Connector/J 3.1.7, we've made available a variant of the driver that will automatically send queries to a read/write master, or a failover or round-robin loadbalanced set of slaves based on the state of `Connection.getReadOnly()' . An application signals that it wants a transaction to be read-only by calling `Connection.setReadOnly(true)', this replication-aware connection will use one of the slave connections, which are load-balanced per-vm using a round-robin scheme (a given connection is sticky to a slave unless that slave is removed from service). If you have a write transaction, or if you have a read that is time-sensitive (remember, replication in MySQL is asynchronous), set the connection to be not read-only, by calling `Connection.setReadOnly(false)' and the driver will ensure that further calls are sent to the master MySQL server. The driver takes care of propagating the current state of autocommit, isolation level, and catalog between all of the connections that it uses to accomplish this load balancing functionality. To enable this functionality, use the " `com.mysql.jdbc.ReplicationDriver' " class when configuring your application server's connection pool or when creating an instance of a JDBC driver for your standalone application. Because it accepts the same URL format as the standard MySQL JDBC driver, `ReplicationDriver' does not currently work with `java.sql.DriverManager' -based connection creation unless it is the only MySQL JDBC driver registered with the `DriverManager' . Here is a short, simple example of how ReplicationDriver might be used in a standalone application. import java.sql.Connection; import java.sql.ResultSet; import java.util.Properties; import com.mysql.jdbc.ReplicationDriver; public class ReplicationDriverDemo { public static void main(String[] args) throws Exception { ReplicationDriver driver = new ReplicationDriver(); Properties props = new Properties(); // We want this for failover on the slaves props.put("autoReconnect", "true"); // We want to load balance between the slaves props.put("roundRobinLoadBalance", "true"); props.put("user", "foo"); props.put("password", "bar"); // // Looks like a normal MySQL JDBC url, with a // comma-separated list of hosts, the first // being the 'master', the rest being any number // of slaves that the driver will load balance against // Connection conn = driver.connect("jdbc:mysql:replication://master,slave1,slave2,slave3/test", props); // // Perform read/write work on the master // by setting the read-only flag to "false" // conn.setReadOnly(false); conn.setAutoCommit(false); conn.createStatement().executeUpdate("UPDATE some_table ...."); conn.commit(); // // Now, do a query from a slave, the driver automatically picks one // from the list // conn.setReadOnly(true); ResultSet rs = conn.createStatement().executeQuery("SELECT a,b FROM alt_table"); ....... } } You may also want to investigate the Load Balancing JDBC Pool (lbpol) tool, which provides a wrapper around the standard JDBC driver and enables you to use DB connection pools that includes checks for system failures and uneven load distribution. For more information, see Load Balancing JDBC Pool (lbpool) (http://code.tailrank.com/lbpool).  File: manual.info, Node: connector-j-reference-error-sqlstates, Prev: connector-j-reference-replication-connection, Up: connector-j-reference 21.3.4.7 Mapping MySQL Error Numbers to SQLStates ................................................. The table below provides a mapping of the MySQL Error Numbers to `SQL States' *Mapping of MySQL Error Numbers to SQLStates* MySQL Error MySQL Error Name Legacy SQL Standard Number (X/Open) SQLState SQLState 1022 ER_DUP_KEY S1000 23000 1037 ER_OUTOFMEMORY S1001 HY001 1038 ER_OUT_OF_SORTMEMORY S1001 HY001 1040 ER_CON_COUNT_ERROR 08004 08004 1042 ER_BAD_HOST_ERROR 08004 08S01 1043 ER_HANDSHAKE_ERROR 08004 08S01 1044 ER_DBACCESS_DENIED_ERROR S1000 42000 1045 ER_ACCESS_DENIED_ERROR 28000 28000 1047 ER_UNKNOWN_COM_ERROR 08S01 HY000 1050 ER_TABLE_EXISTS_ERROR S1000 42S01 1051 ER_BAD_TABLE_ERROR 42S02 42S02 1052 ER_NON_UNIQ_ERROR S1000 23000 1053 ER_SERVER_SHUTDOWN S1000 08S01 1054 ER_BAD_FIELD_ERROR S0022 42S22 1055 ER_WRONG_FIELD_WITH_GROUP S1009 42000 1056 ER_WRONG_GROUP_FIELD S1009 42000 1057 ER_WRONG_SUM_SELECT S1009 42000 1058 ER_WRONG_VALUE_COUNT 21S01 21S01 1059 ER_TOO_LONG_IDENT S1009 42000 1060 ER_DUP_FIELDNAME S1009 42S21 1061 ER_DUP_KEYNAME S1009 42000 1062 ER_DUP_ENTRY S1009 23000 1063 ER_WRONG_FIELD_SPEC S1009 42000 1064 ER_PARSE_ERROR 42000 42000 1065 ER_EMPTY_QUERY 42000 42000 1066 ER_NONUNIQ_TABLE S1009 42000 1067 ER_INVALID_DEFAULT S1009 42000 1068 ER_MULTIPLE_PRI_KEY S1009 42000 1069 ER_TOO_MANY_KEYS S1009 42000 1070 ER_TOO_MANY_KEY_PARTS S1009 42000 1071 ER_TOO_LONG_KEY S1009 42000 1072 ER_KEY_COLUMN_DOES_NOT_EXITS S1009 42000 1073 ER_BLOB_USED_AS_KEY S1009 42000 1074 ER_TOO_BIG_FIELDLENGTH S1009 42000 1075 ER_WRONG_AUTO_KEY S1009 42000 1080 ER_FORCING_CLOSE S1000 08S01 1081 ER_IPSOCK_ERROR 08S01 08S01 1082 ER_NO_SUCH_INDEX S1009 42S12 1083 ER_WRONG_FIELD_TERMINATORS S1009 42000 1084 ER_BLOBS_AND_NO_TERMINATED S1009 42000 1090 ER_CANT_REMOVE_ALL_FIELDS S1000 42000 1091 ER_CANT_DROP_FIELD_OR_KEY S1000 42000 1101 ER_BLOB_CANT_HAVE_DEFAULT S1000 42000 1102 ER_WRONG_DB_NAME S1000 42000 1103 ER_WRONG_TABLE_NAME S1000 42000 1104 ER_TOO_BIG_SELECT S1000 42000 1106 ER_UNKNOWN_PROCEDURE S1000 42000 1107 ER_WRONG_PARAMCOUNT_TO_PROCEDURES1000 42000 1109 ER_UNKNOWN_TABLE S1000 42S02 1110 ER_FIELD_SPECIFIED_TWICE S1000 42000 1112 ER_UNSUPPORTED_EXTENSION S1000 42000 1113 ER_TABLE_MUST_HAVE_COLUMNS S1000 42000 1115 ER_UNKNOWN_CHARACTER_SET S1000 42000 1118 ER_TOO_BIG_ROWSIZE S1000 42000 1120 ER_WRONG_OUTER_JOIN S1000 42000 1121 ER_NULL_COLUMN_IN_INDEX S1000 42000 1129 ER_HOST_IS_BLOCKED 08004 HY000 1130 ER_HOST_NOT_PRIVILEGED 08004 HY000 1131 ER_PASSWORD_ANONYMOUS_USER S1000 42000 1132 ER_PASSWORD_NOT_ALLOWED S1000 42000 1133 ER_PASSWORD_NO_MATCH S1000 42000 1136 ER_WRONG_VALUE_COUNT_ON_ROW S1000 21S01 1138 ER_INVALID_USE_OF_NULL S1000 42000 1139 ER_REGEXP_ERROR S1000 42000 1140 ER_MIX_OF_GROUP_FUNC_AND_FIELDSS1000 42000 1141 ER_NONEXISTING_GRANT S1000 42000 1142 ER_TABLEACCESS_DENIED_ERROR S1000 42000 1143 ER_COLUMNACCESS_DENIED_ERROR S1000 42000 1144 ER_ILLEGAL_GRANT_FOR_TABLE S1000 42000 1145 ER_GRANT_WRONG_HOST_OR_USER S1000 42000 1146 ER_NO_SUCH_TABLE S1000 42S02 1147 ER_NONEXISTING_TABLE_GRANT S1000 42000 1148 ER_NOT_ALLOWED_COMMAND S1000 42000 1149 ER_SYNTAX_ERROR S1000 42000 1152 ER_ABORTING_CONNECTION S1000 08S01 1153 ER_NET_PACKET_TOO_LARGE S1000 08S01 1154 ER_NET_READ_ERROR_FROM_PIPE S1000 08S01 1155 ER_NET_FCNTL_ERROR S1000 08S01 1156 ER_NET_PACKETS_OUT_OF_ORDER S1000 08S01 1157 ER_NET_UNCOMPRESS_ERROR S1000 08S01 1158 ER_NET_READ_ERROR S1000 08S01 1159 ER_NET_READ_INTERRUPTED S1000 08S01 1160 ER_NET_ERROR_ON_WRITE S1000 08S01 1161 ER_NET_WRITE_INTERRUPTED S1000 08S01 1162 ER_TOO_LONG_STRING S1000 42000 1163 ER_TABLE_CANT_HANDLE_BLOB S1000 42000 1164 ER_TABLE_CANT_HANDLE_AUTO_INCREMENTS1000 42000 1166 ER_WRONG_COLUMN_NAME S1000 42000 1167 ER_WRONG_KEY_COLUMN S1000 42000 1169 ER_DUP_UNIQUE S1000 23000 1170 ER_BLOB_KEY_WITHOUT_LENGTH S1000 42000 1171 ER_PRIMARY_CANT_HAVE_NULL S1000 42000 1172 ER_TOO_MANY_ROWS S1000 42000 1173 ER_REQUIRES_PRIMARY_KEY S1000 42000 1177 ER_CHECK_NO_SUCH_TABLE S1000 42000 1178 ER_CHECK_NOT_IMPLEMENTED S1000 42000 1179 ER_CANT_DO_THIS_DURING_AN_TRANSACTIONS1000 25000 1184 ER_NEW_ABORTING_CONNECTION S1000 08S01 1189 ER_MASTER_NET_READ S1000 08S01 1190 ER_MASTER_NET_WRITE S1000 08S01 1203 ER_TOO_MANY_USER_CONNECTIONS S1000 42000 1205 ER_LOCK_WAIT_TIMEOUT 41000 41000 1207 ER_READ_ONLY_TRANSACTION S1000 25000 1211 ER_NO_PERMISSION_TO_CREATE_USERS1000 42000 1213 ER_LOCK_DEADLOCK 41000 40001 1216 ER_NO_REFERENCED_ROW S1000 23000 1217 ER_ROW_IS_REFERENCED S1000 23000 1218 ER_CONNECT_TO_MASTER S1000 08S01 1222 ER_WRONG_NUMBER_OF_COLUMNS_IN_SELECTS1000 21000 1226 ER_USER_LIMIT_REACHED S1000 42000 1230 ER_NO_DEFAULT S1000 42000 1231 ER_WRONG_VALUE_FOR_VAR S1000 42000 1232 ER_WRONG_TYPE_FOR_VAR S1000 42000 1234 ER_CANT_USE_OPTION_HERE S1000 42000 1235 ER_NOT_SUPPORTED_YET S1000 42000 1239 ER_WRONG_FK_DEF S1000 42000 1241 ER_OPERAND_COLUMNS S1000 21000 1242 ER_SUBQUERY_NO_1_ROW S1000 21000 1247 ER_ILLEGAL_REFERENCE S1000 42S22 1248 ER_DERIVED_MUST_HAVE_ALIAS S1000 42000 1249 ER_SELECT_REDUCED S1000 01000 1250 ER_TABLENAME_NOT_ALLOWED_HERE S1000 42000 1251 ER_NOT_SUPPORTED_AUTH_MODE S1000 08004 1252 ER_SPATIAL_CANT_HAVE_NULL S1000 42000 1253 ER_COLLATION_CHARSET_MISMATCH S1000 42000 1261 ER_WARN_TOO_FEW_RECORDS S1000 01000 1262 ER_WARN_TOO_MANY_RECORDS S1000 01000 1263 ER_WARN_NULL_TO_NOTNULL S1000 01000 1264 ER_WARN_DATA_OUT_OF_RANGE S1000 01000 1265 ER_WARN_DATA_TRUNCATED S1000 01000 1280 ER_WRONG_NAME_FOR_INDEX S1000 42000 1281 ER_WRONG_NAME_FOR_CATALOG S1000 42000 1286 ER_UNKNOWN_STORAGE_ENGINE S1000 42000  File: manual.info, Node: connector-j-usagenotes, Next: connector-j-support, Prev: connector-j-reference, Up: connector-j 21.3.5 Connector/J Notes and Tips --------------------------------- * Menu: * connector-j-usagenotes-basic:: Basic JDBC Concepts * connector-j-usagenotes-j2ee:: Using Connector/J with J2EE and Other Java Frameworks * connector-j-usagenotes-troubleshooting:: Connector/J: Common Problems and Solutions  File: manual.info, Node: connector-j-usagenotes-basic, Next: connector-j-usagenotes-j2ee, Prev: connector-j-usagenotes, Up: connector-j-usagenotes 21.3.5.1 Basic JDBC Concepts ............................ * Menu: * connector-j-usagenotes-connect-drivermanager:: Connecting to MySQL Using the `DriverManager' Interface * connector-j-usagenotes-statements:: Using Statements to Execute SQL * connector-j-usagenotes-statements-callable:: Using `CallableStatements' to Execute Stored Procedures * connector-j-usagenotes-last-insert-id:: Retrieving `AUTO_INCREMENT' Column Values This section provides some general JDBC background.  File: manual.info, Node: connector-j-usagenotes-connect-drivermanager, Next: connector-j-usagenotes-statements, Prev: connector-j-usagenotes-basic, Up: connector-j-usagenotes-basic 21.3.5.2 Connecting to MySQL Using the `DriverManager' Interface ................................................................ When you are using JDBC outside of an application server, the `DriverManager' class manages the establishment of Connections. The `DriverManager' needs to be told which JDBC drivers it should try to make Connections with. The easiest way to do this is to use `Class.forName()' on the class that implements the `java.sql.Driver' interface. With MySQL Connector/J, the name of this class is `com.mysql.jdbc.Driver'. With this method, you could use an external configuration file to supply the driver class name and driver parameters to use when connecting to a database. The following section of Java code shows how you might register MySQL Connector/J from the `main()' method of your application. If testing this code please ensure you read the installation section first at *Note connector-j-installing::, to make sure you have connector installed correctly and the `CLASSPATH' set up. Also, ensure that MySQL is configured to accept external TCP/IP connections. import java.sql.Connection; import java.sql.DriverManager; import java.sql.SQLException; // Notice, do not import com.mysql.jdbc.* // or you will have problems! public class LoadDriver { public static void main(String[] args) { try { // The newInstance() call is a work around for some // broken Java implementations Class.forName("com.mysql.jdbc.Driver").newInstance(); } catch (Exception ex) { // handle the error } } } After the driver has been registered with the `DriverManager', you can obtain a `Connection' instance that is connected to a particular database by calling `DriverManager.getConnection()': If you have not already done so, please review the section *Note connector-j-usagenotes-connect-drivermanager:: before working with these examples. This example shows how you can obtain a `Connection' instance from the `DriverManager'. There are a few different signatures for the `getConnection()' method. You should see the API documentation that comes with your JDK for more specific information on how to use them. import java.sql.Connection; import java.sql.DriverManager; import java.sql.SQLException; Connection conn = null; ... try { conn = DriverManager.getConnection("jdbc:mysql://localhost/test?" + "user=monty&password=greatsqldb"); // Do something with the Connection ... } catch (SQLException ex) { // handle any errors System.out.println("SQLException: " + ex.getMessage()); System.out.println("SQLState: " + ex.getSQLState()); System.out.println("VendorError: " + ex.getErrorCode()); } Once a Connection is established, it can be used to create Statement and PreparedStatement objects, as well as retrieve metadata about the database. This is explained in the following sections.  File: manual.info, Node: connector-j-usagenotes-statements, Next: connector-j-usagenotes-statements-callable, Prev: connector-j-usagenotes-connect-drivermanager, Up: connector-j-usagenotes-basic 21.3.5.3 Using Statements to Execute SQL ........................................ Statement objects allow you to execute basic SQL queries and retrieve the results through the `ResultSet' class which is described later. To create a Statement instance, you call the `createStatement()' method on the `Connection' object you have retrieved using one of the `DriverManager.getConnection()' or `DataSource.getConnection()' methods described earlier. Once you have a Statement instance, you can execute a *Note `SELECT': select. query by calling the `executeQuery(String)' method with the SQL you want to use. To update data in the database, use the `executeUpdate(String SQL)' method. This method returns the number of rows matched by the update statement, not the number of rows that were modified. If you do not know ahead of time whether the SQL statement will be a *Note `SELECT': select. or an *Note `UPDATE': update./*Note `INSERT': insert, then you can use the `execute(String SQL)' method. This method will return true if the SQL query was a *Note `SELECT': select, or false if it was an *Note `UPDATE': update, *Note `INSERT': insert, or *Note `DELETE': delete. statement. If the statement was a *Note `SELECT': select. query, you can retrieve the results by calling the `getResultSet()' method. If the statement was an *Note `UPDATE': update, *Note `INSERT': insert, or *Note `DELETE': delete. statement, you can retrieve the affected rows count by calling `getUpdateCount()' on the Statement instance. import java.sql.Connection; import java.sql.DriverManager; import java.sql.SQLException; import java.sql.Statement; import java.sql.ResultSet; // assume that conn is an already created JDBC connection (see previous examples) Statement stmt = null; ResultSet rs = null; try { stmt = conn.createStatement(); rs = stmt.executeQuery("SELECT foo FROM bar"); // or alternatively, if you don't know ahead of time that // the query will be a SELECT... if (stmt.execute("SELECT foo FROM bar")) { rs = stmt.getResultSet(); } // Now do something with the ResultSet .... } catch (SQLException ex){ // handle any errors System.out.println("SQLException: " + ex.getMessage()); System.out.println("SQLState: " + ex.getSQLState()); System.out.println("VendorError: " + ex.getErrorCode()); } finally { // it is a good idea to release // resources in a finally{} block // in reverse-order of their creation // if they are no-longer needed if (rs != null) { try { rs.close(); } catch (SQLException sqlEx) { } // ignore rs = null; } if (stmt != null) { try { stmt.close(); } catch (SQLException sqlEx) { } // ignore stmt = null; } }  File: manual.info, Node: connector-j-usagenotes-statements-callable, Next: connector-j-usagenotes-last-insert-id, Prev: connector-j-usagenotes-statements, Up: connector-j-usagenotes-basic 21.3.5.4 Using `CallableStatements' to Execute Stored Procedures ................................................................ Starting with MySQL server version 5.0 when used with Connector/J 3.1.1 or newer, the java.sql.CallableStatement interface is fully implemented with the exception of the `getParameterMetaData()' method. For more information on MySQL stored procedures, please refer to `http://dev.mysql.com/doc/mysql/en/stored-routines.html'. Connector/J exposes stored procedure functionality through JDBC's CallableStatement interface. *Note*: Current versions of MySQL server do not return enough information for the JDBC driver to provide result set metadata for callable statements. This means that when using `CallableStatement', `ResultSetMetaData' may return `NULL'. The following example shows a stored procedure that returns the value of inOutParam incremented by 1, and the string passed in using inputParam as a ResultSet: CREATE PROCEDURE demoSp(IN inputParam VARCHAR(255), \ INOUT inOutParam INT) BEGIN DECLARE z INT; SET z = inOutParam + 1; SET inOutParam = z; SELECT inputParam; SELECT CONCAT('zyxw', inputParam); END To use the `demoSp' procedure with Connector/J, follow these steps: 1. Prepare the callable statement by using `Connection.prepareCall()' . Notice that you have to use JDBC escape syntax, and that the parentheses surrounding the parameter placeholders are not optional: import java.sql.CallableStatement; ... // // Prepare a call to the stored procedure 'demoSp' // with two parameters // // Notice the use of JDBC-escape syntax ({call ...}) // CallableStatement cStmt = conn.prepareCall("{call demoSp(?, ?)}"); cStmt.setString(1, "abcdefg"); *Note*: `Connection.prepareCall()' is an expensive method, due to the metadata retrieval that the driver performs to support output parameters. For performance reasons, you should try to minimize unnecessary calls to `Connection.prepareCall()' by reusing CallableStatement instances in your code. 2. Register the output parameters (if any exist) To retrieve the values of output parameters (parameters specified as `OUT' or `INOUT' when you created the stored procedure), JDBC requires that they be specified before statement execution using the various `registerOutputParameter()' methods in the CallableStatement interface: import java.sql.Types; ... // // Connector/J supports both named and indexed // output parameters. You can register output // parameters using either method, as well // as retrieve output parameters using either // method, regardless of what method was // used to register them. // // The following examples show how to use // the various methods of registering // output parameters (you should of course // use only one registration per parameter). // // // Registers the second parameter as output, and // uses the type 'INTEGER' for values returned from // getObject() // cStmt.registerOutParameter(2, Types.INTEGER); // // Registers the named parameter 'inOutParam', and // uses the type 'INTEGER' for values returned from // getObject() // cStmt.registerOutParameter("inOutParam", Types.INTEGER); ... 3. Set the input parameters (if any exist) Input and in/out parameters are set as for PreparedStatement objects. However, CallableStatement also supports setting parameters by name: ... // // Set a parameter by index // cStmt.setString(1, "abcdefg"); // // Alternatively, set a parameter using // the parameter name // cStmt.setString("inputParameter", "abcdefg"); // // Set the 'in/out' parameter using an index // cStmt.setInt(2, 1); // // Alternatively, set the 'in/out' parameter // by name // cStmt.setInt("inOutParam", 1); ... 4. Execute the CallableStatement, and retrieve any result sets or output parameters. Although CallableStatement supports calling any of the Statement execute methods (`executeUpdate()', `executeQuery()' or `execute()'), the most flexible method to call is `execute()', as you do not need to know ahead of time if the stored procedure returns result sets: ... boolean hadResults = cStmt.execute(); // // Process all returned result sets // while (hadResults) { ResultSet rs = cStmt.getResultSet(); // process result set ... hadResults = cStmt.getMoreResults(); } // // Retrieve output parameters // // Connector/J supports both index-based and // name-based retrieval // int outputValue = cStmt.getInt(2); // index-based outputValue = cStmt.getInt("inOutParam"); // name-based ...  File: manual.info, Node: connector-j-usagenotes-last-insert-id, Prev: connector-j-usagenotes-statements-callable, Up: connector-j-usagenotes-basic 21.3.5.5 Retrieving `AUTO_INCREMENT' Column Values .................................................. Before version 3.0 of the JDBC API, there was no standard way of retrieving key values from databases that supported auto increment or identity columns. With older JDBC drivers for MySQL, you could always use a MySQL-specific method on the Statement interface, or issue the query `SELECT LAST_INSERT_ID()' after issuing an *Note `INSERT': insert. to a table that had an `AUTO_INCREMENT' key. Using the MySQL-specific method call isn't portable, and issuing a *Note `SELECT': select. to get the `AUTO_INCREMENT' key's value requires another round-trip to the database, which isn't as efficient as possible. The following code snippets demonstrate the three different ways to retrieve `AUTO_INCREMENT' values. First, we demonstrate the use of the new JDBC-3.0 method `getGeneratedKeys()' which is now the preferred method to use if you need to retrieve `AUTO_INCREMENT' keys and have access to JDBC-3.0. The second example shows how you can retrieve the same value using a standard `SELECT LAST_INSERT_ID()' query. The final example shows how updatable result sets can retrieve the `AUTO_INCREMENT' value when using the `insertRow()' method. Statement stmt = null; ResultSet rs = null; try { // // Create a Statement instance that we can use for // 'normal' result sets assuming you have a // Connection 'conn' to a MySQL database already // available stmt = conn.createStatement(java.sql.ResultSet.TYPE_FORWARD_ONLY, java.sql.ResultSet.CONCUR_UPDATABLE); // // Issue the DDL queries for the table for this example // stmt.executeUpdate("DROP TABLE IF EXISTS autoIncTutorial"); stmt.executeUpdate( "CREATE TABLE autoIncTutorial (" + "priKey INT NOT NULL AUTO_INCREMENT, " + "dataField VARCHAR(64), PRIMARY KEY (priKey))"); // // Insert one row that will generate an AUTO INCREMENT // key in the 'priKey' field // stmt.executeUpdate( "INSERT INTO autoIncTutorial (dataField) " + "values ('Can I Get the Auto Increment Field?')", Statement.RETURN_GENERATED_KEYS); // // Example of using Statement.getGeneratedKeys() // to retrieve the value of an auto-increment // value // int autoIncKeyFromApi = -1; rs = stmt.getGeneratedKeys(); if (rs.next()) { autoIncKeyFromApi = rs.getInt(1); } else { // throw an exception from here } rs.close(); rs = null; System.out.println("Key returned from getGeneratedKeys():" + autoIncKeyFromApi); } finally { if (rs != null) { try { rs.close(); } catch (SQLException ex) { // ignore } } if (stmt != null) { try { stmt.close(); } catch (SQLException ex) { // ignore } } } Statement stmt = null; ResultSet rs = null; try { // // Create a Statement instance that we can use for // 'normal' result sets. stmt = conn.createStatement(); // // Issue the DDL queries for the table for this example // stmt.executeUpdate("DROP TABLE IF EXISTS autoIncTutorial"); stmt.executeUpdate( "CREATE TABLE autoIncTutorial (" + "priKey INT NOT NULL AUTO_INCREMENT, " + "dataField VARCHAR(64), PRIMARY KEY (priKey))"); // // Insert one row that will generate an AUTO INCREMENT // key in the 'priKey' field // stmt.executeUpdate( "INSERT INTO autoIncTutorial (dataField) " + "values ('Can I Get the Auto Increment Field?')"); // // Use the MySQL LAST_INSERT_ID() // function to do the same thing as getGeneratedKeys() // int autoIncKeyFromFunc = -1; rs = stmt.executeQuery("SELECT LAST_INSERT_ID()"); if (rs.next()) { autoIncKeyFromFunc = rs.getInt(1); } else { // throw an exception from here } rs.close(); System.out.println("Key returned from " + "'SELECT LAST_INSERT_ID()': " + autoIncKeyFromFunc); } finally { if (rs != null) { try { rs.close(); } catch (SQLException ex) { // ignore } } if (stmt != null) { try { stmt.close(); } catch (SQLException ex) { // ignore } } } Statement stmt = null; ResultSet rs = null; try { // // Create a Statement instance that we can use for // 'normal' result sets as well as an 'updatable' // one, assuming you have a Connection 'conn' to // a MySQL database already available // stmt = conn.createStatement(java.sql.ResultSet.TYPE_FORWARD_ONLY, java.sql.ResultSet.CONCUR_UPDATABLE); // // Issue the DDL queries for the table for this example // stmt.executeUpdate("DROP TABLE IF EXISTS autoIncTutorial"); stmt.executeUpdate( "CREATE TABLE autoIncTutorial (" + "priKey INT NOT NULL AUTO_INCREMENT, " + "dataField VARCHAR(64), PRIMARY KEY (priKey))"); // // Example of retrieving an AUTO INCREMENT key // from an updatable result set // rs = stmt.executeQuery("SELECT priKey, dataField " + "FROM autoIncTutorial"); rs.moveToInsertRow(); rs.updateString("dataField", "AUTO INCREMENT here?"); rs.insertRow(); // // the driver adds rows at the end // rs.last(); // // We should now be on the row we just inserted // int autoIncKeyFromRS = rs.getInt("priKey"); rs.close(); rs = null; System.out.println("Key returned for inserted row: " + autoIncKeyFromRS); } finally { if (rs != null) { try { rs.close(); } catch (SQLException ex) { // ignore } } if (stmt != null) { try { stmt.close(); } catch (SQLException ex) { // ignore } } } When you run the preceding example code, you should get the following output: Key returned from `getGeneratedKeys()': 1 Key returned from `SELECT LAST_INSERT_ID()': 1 Key returned for inserted row: 2 You should be aware, that at times, it can be tricky to use the `SELECT LAST_INSERT_ID()' query, as that function's value is scoped to a connection. So, if some other query happens on the same connection, the value will be overwritten. On the other hand, the `getGeneratedKeys()' method is scoped by the Statement instance, so it can be used even if other queries happen on the same connection, but not on the same Statement instance.  File: manual.info, Node: connector-j-usagenotes-j2ee, Next: connector-j-usagenotes-troubleshooting, Prev: connector-j-usagenotes-basic, Up: connector-j-usagenotes 21.3.5.6 Using Connector/J with J2EE and Other Java Frameworks .............................................................. * Menu: * connector-j-usagenotes-j2ee-concepts:: General J2EE Concepts * connector-j-usagenotes-tomcat:: Using Connector/J with Tomcat * connector-j-usagenotes-jboss:: Using Connector/J with JBoss * connector-j-usagenotes-spring-config:: Using Connector/J with Spring * connector-j-usagenotes-glassfish-config:: Using Connector/J with GlassFish This section describes how to use Connector/J in several contexts.  File: manual.info, Node: connector-j-usagenotes-j2ee-concepts, Next: connector-j-usagenotes-tomcat, Prev: connector-j-usagenotes-j2ee, Up: connector-j-usagenotes-j2ee 21.3.5.7 General J2EE Concepts .............................. * Menu: * connector-j-usagenotes-j2ee-concepts-connection-pooling:: Understanding Connection Pooling * connector-j-usagenotes-j2ee-concepts-managing-load-balanced-connections:: Managing Load Balanced Connections * connector-j-usagenotes-j2ee-concepts-load-balancing-failover:: Load Balancing Failover Policies This section provides general background on J2EE concepts that pertain to use of Connector/J.  File: manual.info, Node: connector-j-usagenotes-j2ee-concepts-connection-pooling, Next: connector-j-usagenotes-j2ee-concepts-managing-load-balanced-connections, Prev: connector-j-usagenotes-j2ee-concepts, Up: connector-j-usagenotes-j2ee-concepts 21.3.5.8 Understanding Connection Pooling ......................................... Connection pooling is a technique of creating and managing a pool of connections that are ready for use by any thread that needs them. This technique of pooling connections is based on the fact that most applications only need a thread to have access to a JDBC connection when they are actively processing a transaction, which usually take only milliseconds to complete. When not processing a transaction, the connection would otherwise sit idle. Instead, connection pooling enables the idle connection to be used by some other thread to do useful work. In practice, when a thread needs to do work against a MySQL or other database with JDBC, it requests a connection from the pool. When the thread is finished using the connection, it returns it to the pool, so that it may be used by any other threads that want to use it. When the connection is loaned out from the pool, it is used exclusively by the thread that requested it. From a programming point of view, it is the same as if your thread called `DriverManager.getConnection()' every time it needed a JDBC connection, however with connection pooling, your thread may end up using either a new, or already-existing connection. Connection pooling can greatly increase the performance of your Java application, while reducing overall resource usage. The main benefits to connection pooling are: * Reduced connection creation time Although this is not usually an issue with the quick connection setup that MySQL offers compared to other databases, creating new JDBC connections still incurs networking and JDBC driver overhead that will be avoided if connections are recycled. * Simplified programming model When using connection pooling, each individual thread can act as though it has created its own JDBC connection, allowing you to use straight-forward JDBC programming techniques. * Controlled resource usage If you do not use connection pooling, and instead create a new connection every time a thread needs one, your application's resource usage can be quite wasteful and lead to unpredictable behavior under load. Remember that each connection to MySQL has overhead (memory, CPU, context switches, and so forth) on both the client and server side. Every connection limits how many resources there are available to your application as well as the MySQL server. Many of these resources will be used whether or not the connection is actually doing any useful work! Connection pools can be tuned to maximize performance, while keeping resource utilization below the point where your application will start to fail rather than just run slower. Luckily, Sun has standardized the concept of connection pooling in JDBC through the JDBC-2.0 Optional interfaces, and all major application servers have implementations of these APIs that work fine with MySQL Connector/J. Generally, you configure a connection pool in your application server configuration files, and access it through the Java Naming and Directory Interface (JNDI). The following code shows how you might use a connection pool from an application deployed in a J2EE application server: import java.sql.Connection; import java.sql.SQLException; import java.sql.Statement; import javax.naming.InitialContext; import javax.sql.DataSource; public class MyServletJspOrEjb { public void doSomething() throws Exception { /* * Create a JNDI Initial context to be able to * lookup the DataSource * * In production-level code, this should be cached as * an instance or static variable, as it can * be quite expensive to create a JNDI context. * * Note: This code only works when you are using servlets * or EJBs in a J2EE application server. If you are * using connection pooling in standalone Java code, you * will have to create/configure datasources using whatever * mechanisms your particular connection pooling library * provides. */ InitialContext ctx = new InitialContext(); /* * Lookup the DataSource, which will be backed by a pool * that the application server provides. DataSource instances * are also a good candidate for caching as an instance * variable, as JNDI lookups can be expensive as well. */ DataSource ds = (DataSource)ctx.lookup("java:comp/env/jdbc/MySQLDB"); /* * The following code is what would actually be in your * Servlet, JSP or EJB 'service' method...where you need * to work with a JDBC connection. */ Connection conn = null; Statement stmt = null; try { conn = ds.getConnection(); /* * Now, use normal JDBC programming to work with * MySQL, making sure to close each resource when you're * finished with it, which permits the connection pool * resources to be recovered as quickly as possible */ stmt = conn.createStatement(); stmt.execute("SOME SQL QUERY"); stmt.close(); stmt = null; conn.close(); conn = null; } finally { /* * close any jdbc instances here that weren't * explicitly closed during normal code path, so * that we don't 'leak' resources... */ if (stmt != null) { try { stmt.close(); } catch (sqlexception sqlex) { // ignore -- as we can't do anything about it here } stmt = null; } if (conn != null) { try { conn.close(); } catch (sqlexception sqlex) { // ignore -- as we can't do anything about it here } conn = null; } } } } As shown in the example above, after obtaining the JNDI InitialContext, and looking up the DataSource, the rest of the code should look familiar to anyone who has done JDBC programming in the past. The most important thing to remember when using connection pooling is to make sure that no matter what happens in your code (exceptions, flow-of-control, and so forth), connections, and anything created by them (such as statements or result sets) are closed, so that they may be re-used, otherwise they will be stranded, which in the best case means that the MySQL server resources they represent (such as buffers, locks, or sockets) may be tied up for some time, or worst case, may be tied up forever. *What Is the Best Size for my Connection Pool?* As with all other configuration rules-of-thumb, the answer is: it depends. Although the optimal size depends on anticipated load and average database transaction time, the optimum connection pool size is smaller than you might expect. If you take Sun's Java Petstore blueprint application for example, a connection pool of 15-20 connections can serve a relatively moderate load (600 concurrent users) using MySQL and Tomcat with response times that are acceptable. To correctly size a connection pool for your application, you should create load test scripts with tools such as Apache JMeter or The Grinder, and load test your application. An easy way to determine a starting point is to configure your connection pool's maximum number of connections to be unbounded, run a load test, and measure the largest amount of concurrently used connections. You can then work backward from there to determine what values of minimum and maximum pooled connections give the best performance for your particular application. *Validating Connections* MySQL Connector/J has the ability to execute a lightweight ping against a server, in order to validate the connection. In the case of load-balanced connections, this is performed against all active pooled internal connections that are retained. This is beneficial to Java applications using connection pools, as the pool can use this feature to validate connections. Depending on your connection pool and configuration, this validation can be carried out at different times: 1. Before the pool returns a connection to the application. 2. When the application returns a connection to the pool. 3. During periodic checks of idle connections. In order to use this feature you need to specify a validation query in your connection pool that starts with `/* ping */'. Note the syntax must be exactly as specified. This will cause the driver send a ping to the server and return a fake, light-weight, result set. When using a `ReplicationConnection' or `LoadBalancedConnection', the ping will be sent across all active connections. It is critical that the syntax be specified correctly. For example, consider the following snippets: sql = "/* PING */ SELECT 1"; sql = "SELECT 1 /* ping*/"; sql = "/*ping*/ SELECT 1"; sql = " /* ping */ SELECT 1"; sql = "/*to ping or not to ping*/ SELECT 1"; None of the above statements will work. This is because the ping syntax is sensitive to whitespace, capitalization, and placement. The syntax needs to be exact for reasons of efficiency, as this test is done for every statement that is executed: protected static final String PING_MARKER = "/* ping */"; ... if (sql.charAt(0) == '/') { if (sql.startsWith(PING_MARKER)) { doPingInstead(); ... All of the previous statements will issue a normal `SELECT' statement and will *not* be transformed into the lightweight ping. Further, for load-balanced connections the statement will be executed against one connection in the internal pool, rather than validating each underlying physical connection. This results in the non-active physical connections assuming a stale state, and they may die. If Connector/J then re-balances it may select a dead connection, resulting in an exception being passed to the application. To help prevent this you can use `loadBalanceValidateConnectionOnSwapServer' to validate the connection before use. If your Connector/J deployment uses a connection pool that allows you to specify a validation query, this should be taken advantage of, but ensure that the query starts _exactly_ with `/* ping */'. This is particularly important if you are using the load-balancing or replication-aware features of Connector/J, as it will help keep alive connections which otherwise will go stale and die, causing problems later.  File: manual.info, Node: connector-j-usagenotes-j2ee-concepts-managing-load-balanced-connections, Next: connector-j-usagenotes-j2ee-concepts-load-balancing-failover, Prev: connector-j-usagenotes-j2ee-concepts-connection-pooling, Up: connector-j-usagenotes-j2ee-concepts 21.3.5.9 Managing Load Balanced Connections ........................................... Connector/J has long provided an effective means to distribute read/write load across multiple MySQL server instances for Cluster or master-master replication deployments, but until version 5.1.13, managing such deployments frequently required a service outage to redeploy a new configuration. Given that the ease of scaling out by adding additional MySQL Cluster (server) instances is a key element in that product offering, which is also naturally targeted at deployments with very strict availability requirements, it was necessary to add support for online changes of this nature. This is also critical for online upgrades, as the alternative is to take a MySQL Cluster server instance down hard, which will lose any in-process transactions and will also generate application exceptions, if any application is trying to use that particular server instance. Connector/J now has the ability to dynamically configure load-balanced connections. There are two connection string options associated with this functionality: * `loadBalanceConnectionGroup' - This provides the ability to group connections from different sources. This allows you to manage these JDBC sources within a single class-loader in any combination you choose. If they use the same configuration, and you want to manage them as a logical single group, give them the same name. This is the key property for management, if you do not define a name (string) for `loadBalanceConnectionGroup', you cannot manage the connections. All load-balanced connections sharing the same `loadBalanceConnectionGroup' value, regardless of how the application creates them, will be managed together. * `loadBalanceEnableJMX' - The ability to manage the connections is exposed when you define a `loadBalanceConnectionGroup', but if you want to manage this externally, it is necessary to enable JMX by setting this property to `true'. This enables a JMX implementation, which exposes the management and monitoring operations of a connection group. Further, you need to start your application with the `-Dcom.sun.management.jmxremote' JVM flag. You can then perform connect and perform operations using a JMX client such as `jconsole'. Once a connection has been made using the correct connection string options, a number of monitoring properties are available: * Current active host count * Current active physical connection count * Current active logical connection count * Total logical connections created * Total transaction count The following management operations can also be performed: * Add host * Remove host The JMX interface, `com.mysql.jdbc.jmx.LoadBalanceConnectionGroupManagerMBean', has the following methods: * int getActiveHostCount(String group); * int getTotalHostCount(String group); * long getTotalLogicalConnectionCount(String group); * long getActiveLogicalConnectionCount(String group); * long getActivePhysicalConnectionCount(String group); * long getTotalPhysicalConnectionCount(String group); * long getTotalTransactionCount(String group); * void removeHost(String group, String host) throws SQLException; * void stopNewConnectionsToHost(String group, String host) throws SQLException; * void addHost(String group, String host, boolean forExisting); * String getActiveHostsList(String group); * String getRegisteredConnectionGroups(); The `getRegisteredConnectionGroups()' method will return the names of all connection groups defined in that class-loader. You can test this setup with the following code: public class Test { private static String URL = "jdbc:mysql:loadbalance://" + "localhost:3306,localhost:3310/test?" + "loadBalanceConnectionGroup=first&loadBalanceEnableJMX=true"; public static void main(String[] args) throws Exception { new Thread(new Repeater()).start(); new Thread(new Repeater()).start(); new Thread(new Repeater()).start(); } static Connection getNewConnection() throws SQLException, ClassNotFoundException { Class.forName("com.mysql.jdbc.Driver"); return DriverManager.getConnection(URL, "root", ""); } static void executeSimpleTransaction(Connection c, int conn, int trans){ try { c.setAutoCommit(false); Statement s = c.createStatement(); s.executeQuery("SELECT SLEEP(1) /* Connection: " + conn + ", transaction: " + trans + " */"); c.commit(); } catch (SQLException e) { e.printStackTrace(); } } public static class Repeater implements Runnable { public void run() { for(int i=0; i < 100; i++){ try { Connection c = getNewConnection(); for(int j=0; j < 10; j++){ executeSimpleTransaction(c, i, j); Thread.sleep(Math.round(100 * Math.random())); } c.close(); Thread.sleep(100); } catch (Exception e) { e.printStackTrace(); } } } } } After compiling, the application can be started with the `-Dcom.sun.management.jmxremote' flag, to enable remote management. `jconsole' can then be started. The Test main class will be listed by jconsole. Select this and click `Connect'. You can then navigate to the `com.mysql.jdbc.jmx.LoadBalanceConnectionGroupManager' bean. At this point you can click on various operations and examine the returned result. If you now had an additional instance of MySQL running on port 3309, you could ensure that Connector/J starts using it by using the `addHost()', which is exposed in `jconsole'. Note that these operations can be performed dynamically without having to stop the application running.  File: manual.info, Node: connector-j-usagenotes-j2ee-concepts-load-balancing-failover, Prev: connector-j-usagenotes-j2ee-concepts-managing-load-balanced-connections, Up: connector-j-usagenotes-j2ee-concepts 21.3.5.10 Load Balancing Failover Policies .......................................... Connector/J provides a useful load-balancing implementation for Cluster or multi-master deployments. As of Connector/J 5.1.12, this same implementation is used for balancing load between read-only slaves with `ReplicationDriver'. When trying to balance workload between multiple servers, the driver has to determine when it is safe to swap servers, doing so in the middle of a transaction, for example, could cause problems. It is important not to lose state information. For this reason, Connector/J will only try to pick a new server when one of the following happens: 1. At transaction boundaries (transactions are explicitly committed or rolled back). 2. A communication exception (SQL State starting with "08") is encountered. 3. When a `SQLException' matches conditions defined by user, using the extension points defined by the `loadBalanceSQLStateFailover', `loadBalanceSQLExceptionSubclassFailover' or `loadBalanceExceptionChecker' properties. The third condition revolves around three new properties introduced with Connector/J 5.1.13. It allows you to control which `SQLException's trigger failover. * `loadBalanceExceptionChecker' - The `loadBalanceExceptionChecker' property is really the key. This takes a fully-qualified class name which implements the new `com.mysql.jdbc.LoadBalanceExceptionChecker' interface. This interface is very simple, and you only need to implement the following method: public boolean shouldExceptionTriggerFailover(SQLException ex) A `SQLException' is passed in, and a boolean returned. `True' triggers a failover, `false' does not. You can use this to implement your own custom logic. An example where this might be useful is when dealing with transient errors when using MySQL Cluster, where certain buffers may become overloaded. The following code snippet illustrates this: public class NdbLoadBalanceExceptionChecker extends StandardLoadBalanceExceptionChecker { public boolean shouldExceptionTriggerFailover(SQLException ex) { return super.shouldExceptionTriggerFailover(ex) || checkNdbException(ex); } private boolean checkNdbException(SQLException ex){ // Have to parse the message since most NDB errors // are mapped to the same DEMC. return (ex.getMessage().startsWith("Lock wait timeout exceeded") || (ex.getMessage().startsWith("Got temporary error") && ex.getMessage().endsWith("from NDB"))); } } The code above extends `com.mysql.jdbc.StandardLoadBalanceExceptionChecker', which is the default implementation. There are a few convenient shortcuts built into this, for those who want to have some level of control using properties, without writing Java code. This default implementation uses the two remaining properties: `loadBalanceSQLStateFailover' and `loadBalanceSQLExceptionSubclassFailover'. * `loadBalanceSQLStateFailover' - allows you to define a comma-delimited list of `SQLState' code prefixes, against which a `SQLException' is compared. If the prefix matches, failover is triggered. So, for example, the following would trigger a failover if a given `SQLException' starts with "00", or is "12345": loadBalanceSQLStateFailover=00,12345 * `loadBalanceSQLExceptionSubclassFailover' - can be used in conjunction with `loadBalanceSQLStateFailover' or on its own. If you want certain subclasses of `SQLException' to trigger failover, simply provide a comma-delimited list of fully-qualified class or interface names to check against. For example, if you want all `SQLTransientConnectionExceptions' to trigger failover, you would specify: loadBalanceSQLExceptionSubclassFailover=java.sql.SQLTransientConnectionException While the three fail-over conditions enumerated earlier suit most situations, if `auto-commit' is enabled, Connector/J never re-balances, and continues using the same physical connection. This can be problematic, particularly when load-balancing is being used to distribute read-only load across multiple slaves. However, Connector/J can be configured to re-balance after a certain number of statements are executed, when `auto-commit' is enabled. This functionality is dependent upon the following properties: * `loadBalanceAutoCommitStatementThreshold' - defines the number of matching statements which will trigger the driver to potentially swap physical server connections. The default value, 0, retains the behavior that connections with `auto-commit' enabled are never balanced. * `loadBalanceAutoCommitStatementRegex' - the regular expression against which statements must match. The default value, blank, matches all statements. So, for example, using the following properties will cause Connector/J to re-balance after every third statement that contains the string `test': loadBalanceAutoCommitStatementThreshold=3 loadBalanceAutoCommitStatementRegex=.*test.* `loadBalanceAutoCommitStatementRegex' can prove useful in a number of situations. Your application may use temporary tables, server-side session state variables, or connection state, where letting the driver arbitrarily swap physical connections before processing is complete could cause data loss or other problems. This allows you to identify a trigger statement that is only executed when it is safe to swap physical connections.  File: manual.info, Node: connector-j-usagenotes-tomcat, Next: connector-j-usagenotes-jboss, Prev: connector-j-usagenotes-j2ee-concepts, Up: connector-j-usagenotes-j2ee 21.3.5.11 Using Connector/J with Tomcat ....................................... The following instructions are based on the instructions for Tomcat-5.x, available at `http://tomcat.apache.org/tomcat-5.5-doc/jndi-datasource-examples-howto.html' which is current at the time this document was written. First, install the .jar file that comes with Connector/J in `$CATALINA_HOME/common/lib' so that it is available to all applications installed in the container. Next, Configure the JNDI DataSource by adding a declaration resource to `$CATALINA_HOME/conf/server.xml' in the context that defines your web application: ... factory org.apache.commons.dbcp.BasicDataSourceFactory maxActive 10 maxIdle 5 validationQuery SELECT 1 <-- See discussion below for update to this option --> testOnBorrow true testWhileIdle true timeBetweenEvictionRunsMillis 10000 minEvictableIdleTimeMillis 60000 username someuser password somepass driverClassName com.mysql.jdbc.Driver url jdbc:mysql://localhost:3306/test Note that Connector/J 5.1.3 introduced a facility whereby, rather than use a `validationQuery' value of `SELECT 1', it is possible to use `validationQuery' with a value set to `/* ping */'. This sends a ping to the server which then returns a fake result set. This is a lighter weight solution. It also has the advantage that if using `ReplicationConnection' or `LoadBalancedConnection' type connections, the ping will be sent across all active connections. The following XML snippet illustrates how to select this option: validationQuery /* ping */ Note that `/* ping */' has to be specified exactly. In general, you should follow the installation instructions that come with your version of Tomcat, as the way you configure datasources in Tomcat changes from time-to-time, and unfortunately if you use the wrong syntax in your XML file, you will most likely end up with an exception similar to the following: Error: java.sql.SQLException: Cannot load JDBC driver class 'null ' SQL state: null  File: manual.info, Node: connector-j-usagenotes-jboss, Next: connector-j-usagenotes-spring-config, Prev: connector-j-usagenotes-tomcat, Up: connector-j-usagenotes-j2ee 21.3.5.12 Using Connector/J with JBoss ...................................... These instructions cover JBoss-4.x. To make the JDBC driver classes available to the application server, copy the .jar file that comes with Connector/J to the `lib' directory for your server configuration (which is usually called `default'). Then, in the same configuration directory, in the subdirectory named deploy, create a datasource configuration file that ends with "-ds.xml", which tells JBoss to deploy this file as a JDBC Datasource. The file should have the following contents: MySQLDB jdbc:mysql://localhost:3306/dbname com.mysql.jdbc.Driver user pass 5 20 5 com.mysql.jdbc.integration.jboss.ExtendedMysqlExceptionSorter com.mysql.jdbc.integration.jboss.MysqlValidConnectionChecker  File: manual.info, Node: connector-j-usagenotes-spring-config, Next: connector-j-usagenotes-glassfish-config, Prev: connector-j-usagenotes-jboss, Up: connector-j-usagenotes-j2ee 21.3.5.13 Using Connector/J with Spring ....................................... * Menu: * connector-j-usagenotes-spring-config-jdbctemplate:: Using JdbcTemplate * connector-j-usagenotes-spring-config-transactional:: Transactional JDBC Access * connector-j-usagenotes-spring-config-connpooling:: Connection Pooling The Spring Framework is a Java-based application framework designed for assisting in application design by providing a way to configure components. The technique used by Spring is a well known design pattern called Dependency Injection (see Inversion of Control Containers and the Dependency Injection pattern (http://www.martinfowler.com/articles/injection.html)). This article will focus on Java-oriented access to MySQL databases with Spring 2.0. For those wondering, there is a .NET port of Spring appropriately named Spring.NET. Spring is not only a system for configuring components, but also includes support for aspect oriented programming (AOP). This is one of the main benefits and the foundation for Spring's resource and transaction management. Spring also provides utilities for integrating resource management with JDBC and Hibernate. For the examples in this section the MySQL world sample database will be used. The first task is to set up a MySQL data source through Spring. Components within Spring use the "bean" terminology. For example, to configure a connection to a MySQL server supporting the world sample database you might use: In the above example we are assigning values to properties that will be used in the configuration. For the datasource configuration: The placeholders are used to provide values for properties of this bean. This means that you can specify all the properties of the configuration in one place instead of entering the values for each property on each bean. We do, however, need one more bean to pull this all together. The last bean is responsible for actually replacing the placeholders with the property values. Now that we have our MySQL data source configured and ready to go, we write some Java code to access it. The example below will retrieve three random cities and their corresponding country using the data source we configured with Spring. // Create a new application context. this processes the Spring config ApplicationContext ctx = new ClassPathXmlApplicationContext("ex1appContext.xml"); // Retrieve the data source from the application context DataSource ds = (DataSource) ctx.getBean("dataSource"); // Open a database connection using Spring's DataSourceUtils Connection c = DataSourceUtils.getConnection(ds); try { // retrieve a list of three random cities PreparedStatement ps = c.prepareStatement( "select City.Name as 'City', Country.Name as 'Country' " + "from City inner join Country on City.CountryCode = Country.Code " + "order by rand() limit 3"); ResultSet rs = ps.executeQuery(); while(rs.next()) { String city = rs.getString("City"); String country = rs.getString("Country"); System.out.printf("The city %s is in %s%n", city, country); } } catch (SQLException ex) { // something has failed and we print a stack trace to analyse the error ex.printStackTrace(); // ignore failure closing connection try { c.close(); } catch (SQLException e) { } } finally { // properly release our connection DataSourceUtils.releaseConnection(c, ds); } This is very similar to normal JDBC access to MySQL with the main difference being that we are using DataSourceUtils instead of the DriverManager to create the connection. While it may seem like a small difference, the implications are somewhat far reaching. Spring manages this resource in a way similar to a container managed data source in a J2EE application server. When a connection is opened, it can be subsequently accessed in other parts of the code if it is synchronized with a transaction. This makes it possible to treat different parts of your application as transactional instead of passing around a database connection.  File: manual.info, Node: connector-j-usagenotes-spring-config-jdbctemplate, Next: connector-j-usagenotes-spring-config-transactional, Prev: connector-j-usagenotes-spring-config, Up: connector-j-usagenotes-spring-config 21.3.5.14 Using JdbcTemplate ............................ Spring makes extensive use of the Template method design pattern (see Template Method Pattern (http://en.wikipedia.org/wiki/Template_method_pattern)). Our immediate focus will be on the `JdbcTemplate' and related classes, specifically `NamedParameterJdbcTemplate'. The template classes handle obtaining and releasing a connection for data access when one is needed. The next example shows how to use `NamedParameterJdbcTemplate' inside of a DAO (Data Access Object) class to retrieve a random city given a country code. public class Ex2JdbcDao { /** * Data source reference which will be provided by Spring. */ private DataSource dataSource; /** * Our query to find a random city given a country code. Notice * the ":country" parameter toward the end. This is called a * named parameter. */ private String queryString = "select Name from City " + "where CountryCode = :country order by rand() limit 1"; /** * Retrieve a random city using Spring JDBC access classes. */ public String getRandomCityByCountryCode(String cntryCode) { // A template that permits using queries with named parameters NamedParameterJdbcTemplate template = new NamedParameterJdbcTemplate(dataSource); // A java.util.Map is used to provide values for the parameters Map params = new HashMap(); params.put("country", cntryCode); // We query for an Object and specify what class we are expecting return (String)template.queryForObject(queryString, params, String.class); } /** * A JavaBean setter-style method to allow Spring to inject the data source. * @param dataSource */ public void setDataSource(DataSource dataSource) { this.dataSource = dataSource; } } The focus in the above code is on the `getRandomCityByCountryCode()' method. We pass a country code and use the `NamedParameterJdbcTemplate' to query for a city. The country code is placed in a Map with the key "country", which is the parameter is named in the SQL query. To access this code, you need to configure it with Spring by providing a reference to the data source. At this point, we can just grab a reference to the DAO from Spring and call `getRandomCityByCountryCode()'. // Create the application context ApplicationContext ctx = new ClassPathXmlApplicationContext("ex2appContext.xml"); // Obtain a reference to our DAO Ex2JdbcDao dao = (Ex2JdbcDao) ctx.getBean("dao"); String countryCode = "USA"; // Find a few random cities in the US for(int i = 0; i < 4; ++i) System.out.printf("A random city in %s is %s%n", countryCode, dao.getRandomCityByCountryCode(countryCode)); This example shows how to use Spring's JDBC classes to completely abstract away the use of traditional JDBC classes including `Connection' and `PreparedStatement'.  File: manual.info, Node: connector-j-usagenotes-spring-config-transactional, Next: connector-j-usagenotes-spring-config-connpooling, Prev: connector-j-usagenotes-spring-config-jdbctemplate, Up: connector-j-usagenotes-spring-config 21.3.5.15 Transactional JDBC Access ................................... You might be wondering how we can add transactions into our code if we do not deal directly with the JDBC classes. Spring provides a transaction management package that not only replaces JDBC transaction management, but also enables declarative transaction management (configuration instead of code). To use transactional database access, we will need to change the storage engine of the tables in the world database. The downloaded script explicitly creates MyISAM tables which do not support transactional semantics. The InnoDB storage engine does support transactions and this is what we will be using. We can change the storage engine with the following statements. ALTER TABLE City ENGINE=InnoDB; ALTER TABLE Country ENGINE=InnoDB; ALTER TABLE CountryLanguage ENGINE=InnoDB; A good programming practice emphasized by Spring is separating interfaces and implementations. What this means is that we can create a Java interface and only use the operations on this interface without any internal knowledge of what the actual implementation is. We will let Spring manage the implementation and with this it will manage the transactions for our implementation. First you create a simple interface: public interface Ex3Dao { Integer createCity(String name, String countryCode, String district, Integer population); } This interface contains one method that will create a new city record in the database and return the id of the new record. Next you need to create an implementation of this interface. public class Ex3DaoImpl implements Ex3Dao { protected DataSource dataSource; protected SqlUpdate updateQuery; protected SqlFunction idQuery; public Integer createCity(String name, String countryCode, String district, Integer population) { updateQuery.update(new Object[] { name, countryCode, district, population }); return getLastId(); } protected Integer getLastId() { return idQuery.run(); } } You can see that we only operate on abstract query objects here and do not deal directly with the JDBC API. Also, this is the complete implementation. All of our transaction management will be dealt with in the configuration. To get the configuration started, we need to create the DAO. ... ... Now you need to set up the transaction configuration. The first thing you must do is create transaction manager to manage the data source and a specification of what transaction properties are required for the `dao' methods. The preceding code creates a transaction manager that handles transactions for the data source provided to it. The `txAdvice' uses this transaction manager and the attributes specify to create a transaction for all methods. Finally you need to apply this advice with an AOP pointcut. This basically says that all methods called on the `Ex3Dao' interface will be wrapped in a transaction. To make use of this, you only have to retrieve the `dao' from the application context and call a method on the `dao' instance. Ex3Dao dao = (Ex3Dao) ctx.getBean("dao"); Integer id = dao.createCity(name, countryCode, district, pop); We can verify from this that there is no transaction management happening in our Java code and it is all configured with Spring. This is a very powerful notion and regarded as one of the most beneficial features of Spring.  File: manual.info, Node: connector-j-usagenotes-spring-config-connpooling, Prev: connector-j-usagenotes-spring-config-transactional, Up: connector-j-usagenotes-spring-config 21.3.5.16 Connection Pooling ............................ In many situations, such as web applications, there will be a large number of small database transactions. When this is the case, it usually makes sense to create a pool of database connections available for web requests as needed. Although MySQL does not spawn an extra process when a connection is made, there is still a small amount of overhead to create and set up the connection. Pooling of connections also alleviates problems such as collecting large amounts of sockets in the `TIME_WAIT' state. Setting up pooling of MySQL connections with Spring is as simple as changing the data source configuration in the application context. There are a number of configurations that we can use. The first example is based on the Jakarta Commons DBCP library (http://jakarta.apache.org/commons/dbcp/). The example below replaces the source configuration that was based on `DriverManagerDataSource' with DBCP's BasicDataSource. The configuration of the two solutions is very similar. The difference is that DBCP will pool connections to the database instead of creating a new connection every time one is requested. We have also set a parameter here called `initialSize'. This tells DBCP that we want three connections in the pool when it is created. Another way to configure connection pooling is to configure a data source in our J2EE application server. Using JBoss as an example, you can set up the MySQL connection pool by creating a file called `mysql-local-ds.xml' and placing it in the server/default/deploy directory in JBoss. Once we have this setup, we can use JNDI to look it up. With Spring, this lookup is very simple. The data source configuration looks like this.  File: manual.info, Node: connector-j-usagenotes-glassfish-config, Prev: connector-j-usagenotes-spring-config, Up: connector-j-usagenotes-j2ee 21.3.5.17 Using Connector/J with GlassFish .......................................... * Menu: * connector-j-usagenotes-glassfish-config-jsp:: A Simple JSP Application with Glassfish, Connector/J and MySQL * connector-j-usagenotes-glassfish-config-servlet:: A Simple Servlet with Glassfish, Connector/J and MySQL This section explains how to use MySQL Connector/J with Glassfish (tm) Server Open Source Edition 3.0.1. Glassfish can be downloaded from the Glassfish website (https://glassfish.dev.java.net/public/downloadsindex.html#top). Once Glassfish is installed you will need to make sure it can access MySQL Connector/J. To do this copy the MySQL Connector/J JAR file to the directory `GLASSFISH_INSTALL/glassfish/lib'. For example, copy `mysql-connector-java-5.1.12-bin.jar' to `C:\glassfishv3\glassfish\lib'. Restart the Glassfish Application Server. You are now ready to create JDBC Connection Pools and JDBC Resources. *Creating a Connection Pool* 1. In the Glassfish Administration Console, using the navigation tree navigate to `Resources', `JDBC', `Connection Pools'. 2. In the `JDBC Connection Pools' frame click `New'. You will enter a two step wizard. 3. In the `Name' field under `General Settings' enter the name for the connection pool, for example enter MySQLConnPool. 4. In the `Resource Type' field, select `javax.sql.DataSource' from the drop-down listbox. 5. In the `Database Vendor' field, select `MySQL' from the drop-down listbox. Click `Next' to go to the next page of the wizard. 6. You can accept the default settings for General Settings, Pool Settings and Transactions for this example. Scroll down to Additional Properties. 7. In Additional Properties you will need to ensure the following properties are set: * *ServerName* - The server you wish to connect to. For local testing this will be `localhost'. * *User* - The user name with which to connect to MySQL. * *Password* - The corresponding password for the user. * *DatabaseName* - The database you wish to connect to, for example the sample MySQL database `World'. 8. Click `Finish' to exit the wizard. You will be taken to the `JDBC Connection Pools' page where all current connection pools, including the one you just created, will be displayed. 9. In the `JDBC Connection Pools' frame click on the connection pool you just created. Here you can review and edit information about the connection pool. 10. To test your connection pool click the `Ping' button at the top of the frame. A message will be displayed confirming correct operation or otherwise. If an error message is received recheck the previous steps, and ensure that MySQL Connector/J has been correctly copied into the previously specified location. Now that you have created a connection pool you will also need to create a JDBC Resource (data source) for use by your application. *Creating a JDBC Resource* Your Java application will usually reference a data source object to establish a connection with the database. This needs to be created first using the following procedure. * Using the navigation tree in the Glassfish Administration Console, navigate to `Resources', `JDBC', `JDBC Resources'. A list of resources will be displayed in the `JDBC Resources' frame. * Click `New'. The `New JDBC Resource' frame will be displayed. * In the `JNDI Name' field, enter the JNDI name that will be used to access this resource, for example enter jdbc/MySQLDataSource. * In the `Pool Name' field, select a connection pool you want this resource to use from the drop-down listbox. * Optionally, you can enter a description into the `Description' field. * Additional properties can be added if required. * Click `OK' to create the new JDBC resource. The `JDBC Resources' frame will list all available JDBC Resources.  File: manual.info, Node: connector-j-usagenotes-glassfish-config-jsp, Next: connector-j-usagenotes-glassfish-config-servlet, Prev: connector-j-usagenotes-glassfish-config, Up: connector-j-usagenotes-glassfish-config 21.3.5.18 A Simple JSP Application with Glassfish, Connector/J and MySQL ........................................................................ This section shows how to deploy a simple JSP application on Glassfish, that connects to a MySQL database. This example assumes you have already set up a suitable Connection Pool and JDBC Resource, as explained in the preceding sections. It is also assumed you have a sample database installed, such as `world'. The main application code, `index.jsp' is presented here: <%@ page import="java.sql.*, javax.sql.*, java.io.*, javax.naming.*" %> Hello world from JSP <% InitialContext ctx; DataSource ds; Connection conn; Statement stmt; ResultSet rs; try { ctx = new InitialContext(); ds = (DataSource) ctx.lookup("java:comp/env/jdbc/MySQLDataSource"); //ds = (DataSource) ctx.lookup("jdbc/MySQLDataSource"); conn = ds.getConnection(); stmt = conn.createStatement(); rs = stmt.executeQuery("SELECT * FROM Country"); while(rs.next()) { %>

Name: <%= rs.getString("Name") %>

Population: <%= rs.getString("Population") %>

<% } } catch (SQLException se) { %> <%= se.getMessage() %> <% } catch (NamingException ne) { %> <%= ne.getMessage() %> <% } %> In addition two XML files are required: `web.xml', and `sun-web.xml'. There may be other files present, such as classes and images. These files are organized into the directory structure as follows: index.jsp WEB-INF | - web.xml - sun-web.xml The code for `web.xml' is: HelloWebApp jdbc/MySQLDataSource javax.sql.DataSource Container Shareable The code for `sun-web.xml' is: HelloWebApp jdbc/MySQLDataSource jdbc/MySQLDataSource These XML files illustrate a very important aspect of running JDBC applications on Glassfish. On Glassfish it is important to map the string specified for a JDBC resource to its JNDI name, as set up in the Glassfish administration console. In this example, the JNDI name for the JDBC resource, as specified in the Glassfish Administration console when creating the JDBC Resource, was `jdbc/MySQLDataSource'. This must be mapped to the name given in the application. In this example the name specified in the application, `jdbc/MySQLDataSource', and the JNDI name, happen to be the same, but this does not necessarily have to be the case. Note that the XML element is used to specify the name as used in the application source code, and this is mapped to the JNDI name specified using the element, in the file `sun-web.xml'. The resource also has to be created in the `web.xml' file, although the mapping of the resource to a JNDI name takes place in the `sun-web.xml' file. If you do not have this mapping set up correctly in the XML files you will not be able to lookup the data source using a JNDI lookup string such as: ds = (DataSource) ctx.lookup("java:comp/env/jdbc/MySQLDataSource"); You will still be able to access the data source directly using: ds = (DataSource) ctx.lookup("jdbc/MySQLDataSource"); With the source files in place, in the correct directory structure, you are ready to deploy the application: 1. In the navigation tree, navigate to `Applications' - the `Applications' frame will be displayed. Click `Deploy'. 2. You can now deploy an application packaged into a single WAR file from a remote client, or you can choose a packaged file or directory that is locally accessible to the server. If you are simply testing an application locally you can simply point Glassfish at the directory that contains your application, without needing to package the application into a WAR file. 3. Now select the application type from the `Type' drop-down listbox, which in this example is `Web application'. 4. Click OK. Now, when you navigate to the `Applications' frame, you will have the option to `Launch', `Redeploy', or `Restart' your application. You can test your application by clicking `Launch'. The application will connection to the MySQL database and display the Name and Population of countries in the `Country' table.  File: manual.info, Node: connector-j-usagenotes-glassfish-config-servlet, Prev: connector-j-usagenotes-glassfish-config-jsp, Up: connector-j-usagenotes-glassfish-config 21.3.5.19 A Simple Servlet with Glassfish, Connector/J and MySQL ................................................................ This section describes a simple servlet that can be used in the Glassfish environment to access a MySQL database. As with the previous section, this example assumes the sample database `world' is installed. The project is set up with the following directory structure: index.html WEB-INF | - web.xml - sun-web.xml - classes | - HelloWebServlet.java - HelloWebServlet.class The code for the servlet, located in `HelloWebServlet.java', is as follows: import javax.servlet.http.*; import javax.servlet.*; import java.io.*; import java.sql.*; import javax.sql.*; import javax.naming.*; public class HelloWebServlet extends HttpServlet { InitialContext ctx = null; DataSource ds = null; Connection conn = null; PreparedStatement ps = null; ResultSet rs = null; String sql = "SELECT Name, Population FROM Country WHERE Name=?"; public void init () throws ServletException { try { ctx = new InitialContext(); ds = (DataSource) ctx.lookup("java:comp/env/jdbc/MySQLDataSource"); conn = ds.getConnection(); ps = conn.prepareStatement(sql); } catch (SQLException se) { System.out.println("SQLException: "+se.getMessage()); } catch (NamingException ne) { System.out.println("NamingException: "+ne.getMessage()); } } public void destroy () { try { if (rs != null) rs.close(); if (ps != null) ps.close(); if (conn != null) conn.close(); if (ctx != null) ctx.close(); } catch (SQLException se) { System.out.println("SQLException: "+se.getMessage()); } catch (NamingException ne) { System.out.println("NamingException: "+ne.getMessage()); } } public void doPost(HttpServletRequest req, HttpServletResponse resp){ try { String country_name = req.getParameter("country_name"); resp.setContentType("text/html"); PrintWriter writer = resp.getWriter(); writer.println(""); writer.println("

Country: "+country_name+"

"); ps.setString(1, country_name); rs = ps.executeQuery(); if (!rs.next()){ writer.println("

Country does not exist!

"); } else { rs.beforeFirst(); while(rs.next()) { writer.println("

Name: "+rs.getString("Name")+"

"); writer.println("

Population: "+rs.getString("Population")+"

"); } } writer.println(""); writer.close(); } catch (Exception e) { e.printStackTrace(); } } public void doGet(HttpServletRequest req, HttpServletResponse resp){ try { resp.setContentType("text/html"); PrintWriter writer = resp.getWriter(); writer.println(""); writer.println("

Hello from servlet doGet()

"); writer.println(""); writer.close(); } catch (Exception e) { e.printStackTrace(); } } } In the preceding code a basic `doGet()' method is implemented, but is not used in the example. The code to establish the connection with the database is as shown in the previous example, *Note connector-j-usagenotes-glassfish-config-jsp::, and is most conveniently located in the servlet `init()' method. The corresponding freeing of resources is located in the destroy method. The main functionality of the servlet is located in the `doPost()' method. If the user enters nto the input form a country name that can be located in the database, the population of the country is returned. The code is invoked using a POST action associated with the input form. The form is defined in the file `index.html': HelloWebServlet

HelloWebServlet

Please enter country name:

The XML files `web.xml' and `sun-web.xml' are as for the example in the preceding section, *Note connector-j-usagenotes-glassfish-config-jsp::, no additional changes are required. Whe compiling the Java source code, you will need to specify the path to the file `javaee.jar'. On Windows, this can be done as follows: shell> javac -classpath c:\glassfishv3\glassfish\lib\javaee.jar HelloWebServlet.java Once the code is correctly located within its directory structure, and compiled, the application can be deployed in Glassfish. This is done in exactly the same way as described in the preceding section, *Note connector-j-usagenotes-glassfish-config-jsp::. Once deployed the application can be launched from within the Glassfish Administration Console. Enter a country name such as `England', and the application will return `Country does not exist!'. Enter `France', and the application will return a population of 59225700.  File: manual.info, Node: connector-j-usagenotes-troubleshooting, Prev: connector-j-usagenotes-j2ee, Up: connector-j-usagenotes 21.3.5.20 Connector/J: Common Problems and Solutions .................................................... There are a few issues that seem to be commonly encountered often by users of MySQL Connector/J. This section deals with their symptoms, and their resolutions. *Questions* * 21.3.5.3.1: When I try to connect to the database with MySQL Connector/J, I get the following exception: SQLException: Server configuration denies access to data source SQLState: 08001 VendorError: 0 What is going on? I can connect just fine with the MySQL command-line client. * 21.3.5.3.2: My application throws an SQLException 'No Suitable Driver'. Why is this happening? * 21.3.5.3.3: I'm trying to use MySQL Connector/J in an applet or application and I get an exception similar to: SQLException: Cannot connect to MySQL server on host:3306. Is there a MySQL server running on the machine/port you are trying to connect to? (java.security.AccessControlException) SQLState: 08S01 VendorError: 0 * 21.3.5.3.4: I have a servlet/application that works fine for a day, and then stops working overnight * 21.3.5.3.5: I'm trying to use JDBC-2.0 updatable result sets, and I get an exception saying my result set is not updatable. * 21.3.5.3.6: I cannot connect to the MySQL server using Connector/J, and I'm sure the connection paramters are correct. * 21.3.5.3.7: I am trying to connect to my MySQL server within my application, but I get the following error and stack trace: java.net.SocketException MESSAGE: Software caused connection abort: recv failed STACKTRACE: java.net.SocketException: Software caused connection abort: recv failed at java.net.SocketInputStream.socketRead0(Native Method) at java.net.SocketInputStream.read(Unknown Source) at com.mysql.jdbc.MysqlIO.readFully(MysqlIO.java:1392) at com.mysql.jdbc.MysqlIO.readPacket(MysqlIO.java:1414) at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:625) at com.mysql.jdbc.Connection.createNewIO(Connection.java:1926) at com.mysql.jdbc.Connection.(Connection.java:452) at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:411) * 21.3.5.3.8: My application is deployed through JBoss and I am using transactions to handle the statements on the MySQL database. Under heavy loads I am getting a error and stack trace, but these only occur after a fixed period of heavy activity. * 21.3.5.3.9: When using `gcj' an `java.io.CharConversionException' is raised when working with certain character sequences. * 21.3.5.3.10: Updating a table that contains a primary key that is either *Note `FLOAT': numeric-types. or compound primary key that uses *Note `FLOAT': numeric-types. fails to update the table and raises an exception. * 21.3.5.3.11: You get an `ER_NET_PACKET_TOO_LARGE' exception, even though the binary blob size you want to insert using JDBC is safely below the `max_allowed_packet' size. * 21.3.5.3.12: What should you do if you receive error messages similar to the following: `Communications link failure - Last packet sent to the server was X ms ago'? * 21.3.5.3.13: Why does Connector/J not reconnect to MySQL and re-issue the statement after a communication failure, instead of throwing an Exception, even though I use the `autoReconnect' connection string option? * 21.3.5.3.14: How can I use 3-byte UTF8 with Connector/J? * 21.3.5.3.15: How can I use 4-byte UTF8, `utf8mb4' with Connector/J? * 21.3.5.3.16: Using `useServerPrepStmts=false' and certain character encodings can lead to corruption when inserting BLOBs. How can this be avoided? *Questions and Answers* *21.3.5.3.1: ** When I try to connect to the database with MySQL Connector/J, I get the following exception: * SQLException: Server configuration denies access to data source SQLState: 08001 VendorError: 0 * What is going on? I can connect just fine with the MySQL command-line client. * MySQL Connector/J must use TCP/IP sockets to connect to MySQL, as Java does not support Unix Domain Sockets. Therefore, when MySQL Connector/J connects to MySQL, the security manager in MySQL server will use its grant tables to determine whether the connection should be permitted. You must add the necessary security credentials to the MySQL server for this to happen, using the *Note `GRANT': grant. statement to your MySQL Server. See *Note grant::, for more information. *Note*: Testing your connectivity with the *Note `mysql': mysql. command-line client will not work unless you add the `--host' flag, and use something other than `localhost' for the host. The *Note `mysql': mysql. command-line client will use Unix domain sockets if you use the special host name `localhost'. If you are testing connectivity to `localhost', use `127.0.0.1' as the host name instead. *Warning*: Changing privileges and permissions improperly in MySQL can potentially cause your server installation to not have optimal security properties. *21.3.5.3.2: ** My application throws an SQLException 'No Suitable Driver'. Why is this happening? * There are three possible causes for this error: * The Connector/J driver is not in your `CLASSPATH', see *Note connector-j-installing::. * The format of your connection URL is incorrect, or you are referencing the wrong JDBC driver. * When using DriverManager, the `jdbc.drivers' system property has not been populated with the location of the Connector/J driver. *21.3.5.3.3: ** I'm trying to use MySQL Connector/J in an applet or application and I get an exception similar to: * SQLException: Cannot connect to MySQL server on host:3306. Is there a MySQL server running on the machine/port you are trying to connect to? (java.security.AccessControlException) SQLState: 08S01 VendorError: 0 Either you're running an Applet, your MySQL server has been installed with the "-skip-networking" option set, or your MySQL server has a firewall sitting in front of it. Applets can only make network connections back to the machine that runs the web server that served the .class files for the applet. This means that MySQL must run on the same machine (or you must have some sort of port re-direction) for this to work. This also means that you will not be able to test applets from your local file system, you must always deploy them to a web server. MySQL Connector/J can only communicate with MySQL using TCP/IP, as Java does not support Unix domain sockets. TCP/IP communication with MySQL might be affected if MySQL was started with the "-skip-networking" flag, or if it is firewalled. If MySQL has been started with the "-skip-networking" option set (the Debian Linux package of MySQL server does this for example), you need to comment it out in the file /etc/mysql/my.cnf or /etc/my.cnf. Of course your my.cnf file might also exist in the `data' directory of your MySQL server, or anywhere else (depending on how MySQL was compiled for your system). Binaries created by us always look in /etc/my.cnf and [datadir]/my.cnf. If your MySQL server has been firewalled, you will need to have the firewall configured to allow TCP/IP connections from the host where your Java code is running to the MySQL server on the port that MySQL is listening to (by default, 3306). *21.3.5.3.4: ** I have a servlet/application that works fine for a day, and then stops working overnight * MySQL closes connections after 8 hours of inactivity. You either need to use a connection pool that handles stale connections or use the "autoReconnect" parameter (see *Note connector-j-reference-configuration-properties::). Also, you should be catching SQLExceptions in your application and dealing with them, rather than propagating them all the way until your application exits, this is just good programming practice. MySQL Connector/J will set the SQLState (see `java.sql.SQLException.getSQLState()' in your APIDOCS) to "08S01" when it encounters network-connectivity issues during the processing of a query. Your application code should then attempt to re-connect to MySQL at this point. The following (simplistic) example shows what code that can handle these exceptions might look like: public void doBusinessOp() throws SQLException { Connection conn = null; Statement stmt = null; ResultSet rs = null; // // How many times do you want to retry the transaction // (or at least _getting_ a connection)? // int retryCount = 5; boolean transactionCompleted = false; do { try { conn = getConnection(); // assume getting this from a // javax.sql.DataSource, or the // java.sql.DriverManager conn.setAutoCommit(false); // // Okay, at this point, the 'retry-ability' of the // transaction really depends on your application logic, // whether or not you're using autocommit (in this case // not), and whether you're using transactional storage // engines // // For this example, we'll assume that it's _not_ safe // to retry the entire transaction, so we set retry // count to 0 at this point // // If you were using exclusively transaction-safe tables, // or your application could recover from a connection going // bad in the middle of an operation, then you would not // touch 'retryCount' here, and just let the loop repeat // until retryCount == 0. // retryCount = 0; stmt = conn.createStatement(); String query = "SELECT foo FROM bar ORDER BY baz"; rs = stmt.executeQuery(query); while (rs.next()) { } rs.close(); rs = null; stmt.close(); stmt = null; conn.commit(); conn.close(); conn = null; transactionCompleted = true; } catch (SQLException sqlEx) { // // The two SQL states that are 'retry-able' are 08S01 // for a communications error, and 40001 for deadlock. // // Only retry if the error was due to a stale connection, // communications problem or deadlock // String sqlState = sqlEx.getSQLState(); if ("08S01".equals(sqlState) || "40001".equals(sqlState)) { retryCount--; } else { retryCount = 0; } } finally { if (rs != null) { try { rs.close(); } catch (SQLException sqlEx) { // You'd probably want to log this . . . } } if (stmt != null) { try { stmt.close(); } catch (SQLException sqlEx) { // You'd probably want to log this as well . . . } } if (conn != null) { try { // // If we got here, and conn is not null, the // transaction should be rolled back, as not // all work has been done try { conn.rollback(); } finally { conn.close(); } } catch (SQLException sqlEx) { // // If we got an exception here, something // pretty serious is going on, so we better // pass it up the stack, rather than just // logging it. . . throw sqlEx; } } } } while (!transactionCompleted && (retryCount > 0)); } *Note*: Use of the `autoReconnect' option is not recommended because there is no safe method of reconnecting to the MySQL server without risking some corruption of the connection state or database state information. Instead, you should use a connection pool which will enable your application to connect to the MySQL server using an available connection from the pool. The `autoReconnect' facility is deprecated, and may be removed in a future release. *21.3.5.3.5: ** I'm trying to use JDBC-2.0 updatable result sets, and I get an exception saying my result set is not updatable. * Because MySQL does not have row identifiers, MySQL Connector/J can only update result sets that have come from queries on tables that have at least one primary key, the query must select every primary key and the query can only span one table (that is, no joins). This is outlined in the JDBC specification. Note that this issue only occurs when using updatable result sets, and is caused because Connector/J is unable to guarantee that it can identify the correct rows within the result set to be updated without having a unique reference to each row. There is no requirement to have a unique field on a table if you are using *Note `UPDATE': update. or *Note `DELETE': delete. statements on a table where you can individually specify the criteria to be matched using a `WHERE' clause. *21.3.5.3.6: ** I cannot connect to the MySQL server using Connector/J, and I'm sure the connection paramters are correct. * Make sure that the `skip-networking' option has not been enabled on your server. Connector/J must be able to communicate with your server over TCP/IP, named sockets are not supported. Also ensure that you are not filtering connections through a Firewall or other network security system. For more information, see *Note can-not-connect-to-server::. *21.3.5.3.7: ** I am trying to connect to my MySQL server within my application, but I get the following error and stack trace: * java.net.SocketException MESSAGE: Software caused connection abort: recv failed STACKTRACE: java.net.SocketException: Software caused connection abort: recv failed at java.net.SocketInputStream.socketRead0(Native Method) at java.net.SocketInputStream.read(Unknown Source) at com.mysql.jdbc.MysqlIO.readFully(MysqlIO.java:1392) at com.mysql.jdbc.MysqlIO.readPacket(MysqlIO.java:1414) at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:625) at com.mysql.jdbc.Connection.createNewIO(Connection.java:1926) at com.mysql.jdbc.Connection.(Connection.java:452) at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:411) The error probably indicates that you are using a older version of the Connector/J JDBC driver (2.0.14 or 3.0.x) and you are trying to connect to a MySQL server with version 4.1x or newer. The older drivers are not compatible with 4.1 or newer of MySQL as they do not support the newer authentication mechanisms. It is likely that the older version of the Connector/J driver exists within your application directory or your `CLASSPATH' includes the older Connector/J package. *21.3.5.3.8: ** My application is deployed through JBoss and I am using transactions to handle the statements on the MySQL database. Under heavy loads I am getting a error and stack trace, but these only occur after a fixed period of heavy activity. * This is a JBoss, not Connector/J, issue and is connected to the use of transactions. Under heavy loads the time taken for transactions to complete can increase, and the error is caused because you have exceeded the predefined timeout. You can increase the timeout value by setting the `TransactionTimeout' attribute to the `TransactionManagerService' within the `/conf/jboss-service.xml' file (pre-4.0.3) or `/deploy/jta-service.xml' for JBoss 4.0.3 or later. See TransactionTimeoute (http://wiki.jboss.org/wiki/Wiki.jsp?page=TransactionTimeout) within the JBoss wiki for more information. *21.3.5.3.9: ** When using `gcj' an `java.io.CharConversionException' is raised when working with certain character sequences. * This is a known issue with `gcj' which raises an exception when it reaches an unknown character or one it cannot convert. You should add `useJvmCharsetConverters=true' to your connection string to force character conversion outside of the `gcj' libraries, or try a different JDK. *21.3.5.3.10: ** Updating a table that contains a primary key that is either *Note `FLOAT': numeric-types. or compound primary key that uses *Note `FLOAT': numeric-types. fails to update the table and raises an exception. * Connector/J adds conditions to the `WHERE' clause during an *Note `UPDATE': update. to check the old values of the primary key. If there is no match then Connector/J considers this a failure condition and raises an exception. The problem is that rounding differences between supplied values and the values stored in the database may mean that the values never match, and hence the update fails. The issue will affect all queries, not just those from Connector/J. To prevent this issue, use a primary key that does not use *Note `FLOAT': numeric-types. If you have to use a floating point column in your primary key use *Note `DOUBLE': numeric-types. or *Note `DECIMAL': numeric-types. types in place of *Note `FLOAT': numeric-types. *21.3.5.3.11: ** You get an `ER_NET_PACKET_TOO_LARGE' exception, even though the binary blob size you want to insert using JDBC is safely below the `max_allowed_packet' size. * This is because the `hexEscapeBlock()' method in `com.mysql.jdbc.PreparedStatement.streamToBytes()' may almost double the size of your data. *21.3.5.3.12: ** What should you do if you receive error messages similar to the following: `Communications link failure - Last packet sent to the server was X ms ago'? * Generally speaking, this error suggests that the network connection has been closed. There can be several root causes: * Firewalls or routers may clamp down on idle connections (the MySQL client/server protocol does not ping). * The MySQL Server may be closing idle connections which exceed the `wait_timeout' or `interactive_timeout' threshold. To help troubleshoot these issues, the following tips can be used. If a recent (5.1.13+) version of Connector/J is used, you will see an improved level of information compared to earlier versions. Older versions simply display the last time a packet was sent to the server, which is frequently 0 ms ago. This is of limited use, as it may be that a packet was just sent, while a packet from the server has not been received for several hours. Knowing the period of time since Connector/J last received a packet from the server is useful information, so if this is not displayed in your exception message, it is recommended that you update Connector/J. Further, if the time a packet was last sent/received exceeds the `wait_timeout' or `interactive_timeout' threshold, this is noted in the exception message. Although network connections can be volatile, the following can be helpful in avoiding problems: * Ensure connections are valid when used from the connection pool. Use a query that starts with `/* ping */' to execute a lightweight ping instead of full query. Note, the syntax of the ping needs to be exactly as specified here. * Minimize the duration a connection object is left idle while other application logic is executed. * Explicitly validate the connection before using it if the connection has been left idle for an extended period of time. * Ensure that `wait_timeout' and `interactive_timeout' are set sufficiently high. * Ensure that `tcpKeepalive' is enabled. * Ensure that any configurable firewall or router timeout settings allow for the maximum expected connection idle time. *Note*: Do not expect to be able to reuse a connection without problems, if it has being lying idle for a period. If a connection is to be reused after being idle for any length of time, ensure that you explicitly test it before reusing it. *21.3.5.3.13: ** Why does Connector/J not reconnect to MySQL and re-issue the statement after a communication failure, instead of throwing an Exception, even though I use the `autoReconnect' connection string option? * There are several reasons for this. The first is transactional integrity. The MySQL Reference Manual states that `there is no safe method of reconnecting to the MySQL server without risking some corruption of the connection state or database state information'. Consider the following series of statements for example: conn.createStatement().execute( "UPDATE checking_account SET balance = balance - 1000.00 WHERE customer='Smith'"); conn.createStatement().execute( "UPDATE savings_account SET balance = balance + 1000.00 WHERE customer='Smith'"); conn.commit(); Consider the case where the connection to the server fails after the `UPDATE' to `checking_account'. If no exception is thrown, and the application never learns about the problem, it will continue executing. However, the server did not commit the first transaction in this case, so that will get rolled back. But execution continues with the next transaction, and increases the `savings_account' balance by 1000. The application did not receive an exception, so it continued regardless, eventually committing the second transaction, as the commit only applies to the changes made in the new connection. Rather than a transfer taking place, a deposit was made in this example. Note that running with `auto-commit' enabled does not solve this problem. When Connector/J encounters a communication problem, there is no means to determine whether the server processed the currently executing statement or not. The following theoretical states are equally possible: * The server never received the statement, and therefore no related processing occurred on the server. * The server received the statement, executed it in full, but the response was not received by the client. If you are running with `auto-commit' enabled, it is not possible to guarantee the state of data on the server when a communication exception is encountered. The statement may have reached the server, or it may not. All you know is that communication failed at some point, before the client received confirmation (or data) from the server. This does not only affect `auto-commit' statements though. If the communication problem occurred during `Connection.commit()', the question arises of whether the transaction was committed on the server before the communication failed, or whether the server received the commit request at all. The second reason for the generation of exceptions is that transaction-scoped contextual data may be vulnerable, for example: * Temporary tables * User-defined variables * Server-side prepared statements These items are lost when a connection fails, and if the connection silently reconnects without generating an exception, this could be detrimental to the correct execution of your application. In summary, communication errors generate conditions that may well be unsafe for Connector/J to simply ignore by silently reconnecting. It is necessary for the application to be notified. It is then for the application developer to decide how to proceed in the event of connection errors and failures. *21.3.5.3.14: ** How can I use 3-byte UTF8 with Connector/J? * To use 3-byte UTF8 with Connector/J set `characterEncoding=utf8' and set `useUnicode=true' in the connection string. *21.3.5.3.15: ** How can I use 4-byte UTF8, `utf8mb4' with Connector/J? * To use 4-byte UTF8 with Connector/J configure the MySQL server with `character_set_server=utf8mb4'. Connector/J will then use that setting as long as `characterEncoding' has not been set in the connection string. This is equivalent to autodetection of the character set. *21.3.5.3.16: ** Using `useServerPrepStmts=false' and certain character encodings can lead to corruption when inserting BLOBs. How can this be avoided? * When using certain character encodings, such as SJIS, CP932, and BIG5, it is possible that BLOB data contains characters that can be interpreted as control characters, for example, backslash, '\'. This can lead to corrupted data when inserting BLOBs into the database. There are two things that need to be done to avoid this: 1. Set the connection string option `useServerPrepStmts' to `true'. 2. Set `SQL_MODE' to `NO_BACKSLASH_ESCAPES'.  File: manual.info, Node: connector-j-support, Prev: connector-j-usagenotes, Up: connector-j 21.3.6 Connector/J Support -------------------------- * Menu: * connector-j-support-community:: Connector/J Community Support * connector-j-support-bug-report:: How to Report Connector/J Bugs or Problems * connector-j-support-changelog:: Connector/J Change History  File: manual.info, Node: connector-j-support-community, Next: connector-j-support-bug-report, Prev: connector-j-support, Up: connector-j-support 21.3.6.1 Connector/J Community Support ...................................... Oracle provides assistance to the user community by means of its mailing lists. For Connector/J related issues, you can get help from experienced users by using the MySQL and Java mailing list. Archives and subscription information is available online at `http://lists.mysql.com/java'. For information about subscribing to MySQL mailing lists or to browse list archives, visit `http://lists.mysql.com/'. See *Note mailing-lists::. Community support from experienced users is also available through the JDBC Forum (http://forums.mysql.com/list.php?39). You may also find help from other users in the other MySQL Forums, located at `http://forums.mysql.com'. See *Note forums::.  File: manual.info, Node: connector-j-support-bug-report, Next: connector-j-support-changelog, Prev: connector-j-support-community, Up: connector-j-support 21.3.6.2 How to Report Connector/J Bugs or Problems ................................................... The normal place to report bugs is `http://bugs.mysql.com/', which is the address for our bugs database. This database is public, and can be browsed and searched by anyone. If you log in to the system, you will also be able to enter new reports. If you have found a sensitive security bug in MySQL, you can send email to . Writing a good bug report takes patience, but doing it right the first time saves time both for us and for yourself. A good bug report, containing a full test case for the bug, makes it very likely that we will fix the bug in the next release. This section will help you write your report correctly so that you do not waste your time doing things that may not help us much or at all. If you have a repeatable bug report, please report it to the bugs database at `http://bugs.mysql.com/'. Any bug that we are able to repeat has a high chance of being fixed in the next MySQL release. To report other problems, you can use one of the MySQL mailing lists. Remember that it is possible for us to respond to a message containing too much information, but not to one containing too little. People often omit facts because they think they know the cause of a problem and assume that some details do not matter. A good principle is this: If you are in doubt about stating something, state it. It is faster and less troublesome to write a couple more lines in your report than to wait longer for the answer if we must ask you to provide information that was missing from the initial report. The most common errors made in bug reports are (a) not including the version number of Connector/J or MySQL used, and (b) not fully describing the platform on which Connector/J is installed (including the JVM version, and the platform type and version number that MySQL itself is installed on). This is highly relevant information, and in 99 cases out of 100, the bug report is useless without it. Very often we get questions like, `Why doesn't this work for me?' Then we find that the feature requested wasn't implemented in that MySQL version, or that a bug described in a report has already been fixed in newer MySQL versions. Sometimes the error is platform-dependent; in such cases, it is next to impossible for us to fix anything without knowing the operating system and the version number of the platform. If at all possible, you should create a repeatable, standalone testcase that doesn't involve any third-party classes. To streamline this process, we ship a base class for testcases with Connector/J, named 'com.mysql.jdbc.util.BaseBugReport'. To create a testcase for Connector/J using this class, create your own class that inherits from com.mysql.jdbc.util.BaseBugReport and override the methods `setUp()', `tearDown()' and `runTest()'. In the `setUp()' method, create code that creates your tables, and populates them with any data needed to demonstrate the bug. In the `runTest()' method, create code that demonstrates the bug using the tables and data you created in the `setUp' method. In the `tearDown()' method, drop any tables you created in the `setUp()' method. In any of the above three methods, you should use one of the variants of the `getConnection()' method to create a JDBC connection to MySQL: * `getConnection()' - Provides a connection to the JDBC URL specified in `getUrl()'. If a connection already exists, that connection is returned, otherwise a new connection is created. * `getNewConnection()' - Use this if you need to get a new connection for your bug report (that is, there is more than one connection involved). * `getConnection(String url)' - Returns a connection using the given URL. * `getConnection(String url, Properties props)' - Returns a connection using the given URL and properties. If you need to use a JDBC URL that is different from 'jdbc:mysql:///test', override the method `getUrl()' as well. Use the `assertTrue(boolean expression)' and `assertTrue(String failureMessage, boolean expression)' methods to create conditions that must be met in your testcase demonstrating the behavior you are expecting (vs. the behavior you are observing, which is why you are most likely filing a bug report). Finally, create a `main()' method that creates a new instance of your testcase, and calls the `run' method: public static void main(String[] args) throws Exception { new MyBugReport().run(); } Once you have finished your testcase, and have verified that it demonstrates the bug you are reporting, upload it with your bug report to `http://bugs.mysql.com/'.  File: manual.info, Node: connector-j-support-changelog, Prev: connector-j-support-bug-report, Up: connector-j-support 21.3.6.3 Connector/J Change History ................................... The Connector/J Change History (Changelog) is located with the main Changelog for MySQL. See *Note cj-news::.  File: manual.info, Node: connector-mxj, Next: connector-cpp, Prev: connector-j, Up: connectors-apis 21.4 MySQL Connector/MXJ ======================== * Menu: * connector-mxj-overview:: Connector/MXJ Overview * connector-mxj-versions:: Connector/MXJ Versions * connector-mxj-install:: Connector/MXJ Installation * connector-mxj-configuration:: Connector/MXJ Configuration * connector-mxj-ref:: Connector/MXJ Reference * connector-mxj-usagenotes:: Connector/MXJ Notes and Tips * connector-mxj-samples:: Connector/MXJ Samples * connector-mxj-support:: Connector/MXJ Support MySQL Connector/MXJ is a Java Utility package for deploying and managing a MySQL database. Deploying and using MySQL can be as easy as adding another parameter to the JDBC connection url, which will result in the database being started when the first connection is made. This makes it easy for Java developers to deploy applications which require a database by reducing installation barriers for their end-users. MySQL Connector/MXJ makes the MySQL database appear to be a java-based component. It does this by determining what platform the system is running on, selecting the appropriate binary, and launching the executable. It will also optionally deploy an initial database, with any specified parameters. Included are instructions for use with a JDBC driver and deploying as a JMX MBean to JBoss. You can download sources and binaries from: `http://dev.mysql.com/downloads/connector/mxj/' This a beta release and feedback is welcome and encouraged. Please send questions or comments to the MySQL and Java mailing list (http://lists.mysql.com/java).  File: manual.info, Node: connector-mxj-overview, Next: connector-mxj-versions, Prev: connector-mxj, Up: connector-mxj 21.4.1 Connector/MXJ Overview ----------------------------- Connector/MXJ consists of a Java class, a copy of the `mysqld' binary for a specific list of platforms, and associated files and support utilities. The Java class controls the initialization of an instance of the embedded `mysqld' binary, and the ongoing management of the `mysqld' process. The entire sequence and management can be controlled entirely from within Java using the Connector/MXJ Java classes. You can see an overview of the contents of the Connector/MXJ package in the figure below. Connector/MXJ Overview It is important to note that Connector/MXJ is not an embedded version of MySQL, or a version of MySQL written as part of a Java class. Connector/MXJ works through the use of an embedded, compiled binary of `mysqld' as would normally be used when deploying a standard MySQL installation. It is the Connector/MXJ wrapper, support classes and tools, that enable Connector/MXJ to appear as a MySQL instance. When Connector/MXJ is initialized, the corresponding `mysqld' binary for the current platform is extracted, along with a pre-configured data directed. Both are contained within the Connector/MXJ JAR file. The `mysqld' instance is then started, with any additional options as specified during the initialization, and the MySQL database becomes accessible. Because Connector/MXJ works in combination with Connector/J, you can access and integrate with the MySQL instance through a JDBC connection. When you have finished with the server, the instance is terminated, and, by default, any data created during the session is retained within the temporary directory created when the instance was started. Connector/MXJ and the embedded `mysqld' instance can be deployed in a number of environments where relying on an existing database, or installing a MySQL instance would be impossible, including CD-ROM embedded database applications and temporary database requirements within a Java-based application environment.  File: manual.info, Node: connector-mxj-versions, Next: connector-mxj-install, Prev: connector-mxj-overview, Up: connector-mxj 21.4.2 Connector/MXJ Versions ----------------------------- Connector/MXJ 5.x, currently in beta status, includes `mysqld' version 5.x and includes binaries for Linux x86, Mac OS X PPC, Windows XP/NT/2000 x86 and Solaris SPARC. Connector/MXJ 5.x requires the Connector/J 5.x package. A summary of the different MySQL versions supplied with each Connector/MXJ release are shown in the table. Connector/MXJ Version MySQL Version(s) 5.0.11 5.1.40 5.0.9 5.0.51a (CS), 5.0.54 (ES) 5.0.8 5.0.45 (CS), 5.0.46 (ES) 5.0.7 5.0.41 (CS), 5.0.42 (ES) 5.0.6 5.0.37 (CS), 5.0.40 (ES) 5.0.5 5.0.37 (CS), 5.0.36 (ES) 5.0.4 5.0.27 (CS), 5.0.32 (ES) 5.0.3 5.0.22 5.0.2 5.0.19 This guide provides information on the Connector/MXJ 5.x release. For information on using the older releases, please see the documentation included with the appropriate distribution.  File: manual.info, Node: connector-mxj-install, Next: connector-mxj-configuration, Prev: connector-mxj-versions, Up: connector-mxj 21.4.3 Connector/MXJ Installation --------------------------------- * Menu: * connector-mxj-install-platforms:: Supported Platforms * connector-mxj-install-base:: Connector/MXJ Base Installation * connector-mxj-install-quickstart:: Connector/MXJ Quick Start Guide * connector-mxj-install-class:: Deploying Connector/MXJ using Driver Launch * connector-mxj-install-jboss:: Deploying Connector/MXJ within JBoss * connector-mxj-installation-test:: Verifying Installation using JUnit Connector/MXJ does not have a installation application or process, but there are some steps you can follow to make the installation and deployment of Connector/MXJ easier. Before you start, there are some baseline requirements for * Java Runtime Environment (v1.4.0 or newer) if you are only going to deploy the package. * Java Development Kit (v1.4.0 or newer) if you want to build Connector/MXJ from source. * Connector/J 5.0 or newer. Depending on your target installation/deployment environment you may also require: * JBoss - 4.0rc1 or newer * Apache Tomcat - 5.0 or newer * Sun's JMX reference implementation version 1.2.1 (from `http://java.sun.com/products/JavaManagement/')  File: manual.info, Node: connector-mxj-install-platforms, Next: connector-mxj-install-base, Prev: connector-mxj-install, Up: connector-mxj-install 21.4.3.1 Supported Platforms ............................ Connector/MXJ is compatible with any platform supporting Java and MySQL. By default, Connector/MXJ incorporates the `mysqld' binary for a select number of platforms which differs by version. The following platforms have been tested and working as deployment platforms. Support for all the platforms listed below is not included by default. * Linux (i386) * FreeBSD (i386) * Windows NT (x86), Windows 2000 (x86), Windows XP (x86), Windows Vista (x86) * Solaris 8, SPARC 32-bit (compatible with Solaris 8, Solaris 9 and Solaris 10 on SPARC 32-bit and 64-bit platforms) * Mac OS X (PowerPC and Intel) The Connector/MXJ 5.0.8 release includes *Note `mysqld': mysqld. binaries for the following platforms: * Linux (i386) * Windows (x86), compatible with Windows NT, Windows 2000, Windows XP , Windows Vista * Solaris 8, SPARC 32-bit (compatible with Solaris 8, Solaris 9 and Solaris 10 on SPARC 32-bit and 64-bit platforms) * Mac OS X (PowerPC and Intel) For more information on packaging your own Connector/MXJ with the platforms you require, see *Note connector-mxj-usagenotes-packaging::  File: manual.info, Node: connector-mxj-install-base, Next: connector-mxj-install-quickstart, Prev: connector-mxj-install-platforms, Up: connector-mxj-install 21.4.3.2 Connector/MXJ Base Installation ........................................ Because there is no formal installation process, the method, installation directory, and access methods you use for Connector/MXJ are entirely up to your individual requirements. To perform a basic installation, choose a target directory for the files included in the Connector/MXJ package. On Unix/Linux systems you may opt to use a directory such as `/usr/local/connector-mxj'; On Windows, you may want to install the files in the base directory, `C:\Connector-MXJ', or within the `Program Files' directory. To install the files, for a Connector/MXJ 5.0.4 installation: 1. Download the Connector/MXJ package, either in Tar/Gzip format (ideal for Unix/Linux systems) or Zip format (Windows). 2. Extract the files from the package. This will create a directory `mysql-connector-mxj-gpl-[ver]'. Copy and optionally rename this directory to your desired location. 3. For best results, you should update your global `CLASSPATH' variable with the location of the required `jar' files. Within Unix/Linux you can do this globally by editing the global shell profile, or on a user by user basis by editing their individual shell profile. On Windows 2000, Windows NT and Windows XP, you can edit the global `CLASSPATH' by editing the `Environment Variables' configured through the `System' control panel. For Connector/MXJ 5.0.6 and later you need the following JAR files in your `CLASSPATH': * `mysql-connector-mxj-gpl-[ver].jar': contains the main Connector/MXJ classes. * `mysql-connector-mxj-gpl-[ver]-db-files.jar': contains the embedded `mysqld' and database files. * `aspectjrt.jar': the AspectJ runtime library, located in `lib/aspectjrt.jar' in the Connector/MXJ package. * `mysql-connector-java-[ver]-bin.jar': Connector/J, see *Note connector-j::. For Connector/MXJ 5.0.4 and later you need the following JAR files in your `CLASSPATH': * `connector-mxj.jar': contains the main Connector/MXJ classes. * `connector-mxj-db-files.jar': contains the embedded `mysqld' and database files. * `aspectjrt.jar': the AspectJ runtime library, located in `lib/aspectjrt.jar' in the Connector/MXJ package. * `mysql-connector-mxj-gpl-[ver].jar': Connector/J, see *Note connector-j::. For Connector/MXJ 5.0.3 and earlier, you need the following JAR files: * `connector-mxj.jar' * `aspectjrt.jar': the AspectJ runtime library, located in `lib/aspectjrt.jar' in the Connector/MXJ package. * `mysql-connector-mxj-gpl-[ver].jar': Connector/J, see *Note connector-j::.  File: manual.info, Node: connector-mxj-install-quickstart, Next: connector-mxj-install-class, Prev: connector-mxj-install-base, Up: connector-mxj-install 21.4.3.3 Connector/MXJ Quick Start Guide ........................................ Once you have extracted the Connector/MXJ and Connector/J components you can run one of the sample applications that initiates a MySQL instance. You can test the installation by running the `ConnectorMXJUrlTestExample': shell> java ConnectorMXJUrlTestExample jdbc:mysql:mxj://localhost:3336/our_test_app?server.basedir» =/var/tmp/test-mxj&createDatabaseIfNotExist=true&server.initialize-user=true [/var/tmp/test-mxj/bin/mysqld][--no-defaults][--port=3336][--socket=mysql.sock]» [--basedir=/var/tmp/test-mxj][--datadir=/var/tmp/test-mxj/data]» [--pid-file=/var/tmp/test-mxj/data/MysqldResource.pid] [MysqldResource] launching mysqld (driver_launched_mysqld_1) InnoDB: The first specified data file ./ibdata1 did not exist: InnoDB: a new database to be created! 080220 9:40:20 InnoDB: Setting file ./ibdata1 size to 10 MB InnoDB: Database physically writes the file full: wait... 080220 9:40:20 InnoDB: Log file ./ib_logfile0 did not exist: new to be created InnoDB: Setting log file ./ib_logfile0 size to 5 MB InnoDB: Database physically writes the file full: wait... 080220 9:40:20 InnoDB: Log file ./ib_logfile1 did not exist: new to be created InnoDB: Setting log file ./ib_logfile1 size to 5 MB InnoDB: Database physically writes the file full: wait... InnoDB: Doublewrite buffer not found: creating new InnoDB: Doublewrite buffer created InnoDB: Creating foreign key constraint system tables InnoDB: Foreign key constraint system tables created 080220 9:40:21 InnoDB: Started; log sequence number 0 0 080220 9:40:21 [Note] /var/tmp/test-mxj/bin/mysqld: ready for connections. Version: '5.0.51a' socket: 'mysql.sock' port: 3336 MySQL Community Server (GPL) [MysqldResource] mysqld running as process: 2238 ------------------------ SELECT VERSION() ------------------------ 5.0.51a ------------------------ [MysqldResource] stopping mysqld (process: 2238) 080220 9:40:27 [Note] /var/tmp/test-mxj/bin/mysqld: Normal shutdown 080220 9:40:27 InnoDB: Starting shutdown... 080220 9:40:29 InnoDB: Shutdown completed; log sequence number 0 43655 080220 9:40:29 [Note] /var/tmp/test-mxj/bin/mysqld: Shutdown complete [MysqldResource] shutdown complete The above output shows an instance of MySQL starting, the necessary files being created (log files, InnoDB data files) and the MySQL database entering the running state. The instance is then shutdown by Connector/MXJ before the example terminates. *Warning*: You should avoid running your Connector/MXJ application as the `root' user, because this will cause the *Note `mysqld': mysqld. to also be executed with root privileges. For more information, see *Note changing-mysql-user::.  File: manual.info, Node: connector-mxj-install-class, Next: connector-mxj-install-jboss, Prev: connector-mxj-install-quickstart, Up: connector-mxj-install 21.4.3.4 Deploying Connector/MXJ using Driver Launch .................................................... Connector/MXJ and Connector/J work together to enable you to launch an instance of the `mysqld' server through the use of a keyword in the JDBC connection string. Deploying Connector/MXJ within a Java application can be automated through this method, making the deployment of Connector/MXJ a simple process: 1. Download and unzip Connector/MXJ, add `mysql-connector-mxj-gpl-[ver].jar' to the `CLASSPATH'. If you are using Connector/MXJ v5.0.4 or later you will also need to add the `mysql-connector-mxj-gpl-[ver]-db-files.jar' file to your `CLASSPATH'. 2. To the JDBC connection string, embed the `mxj' keyword, for example: `jdbc:mysql:mxj://localhost:PORT/DBNAME'. For more details, see *Note connector-mxj-configuration::.  File: manual.info, Node: connector-mxj-install-jboss, Next: connector-mxj-installation-test, Prev: connector-mxj-install-class, Up: connector-mxj-install 21.4.3.5 Deploying Connector/MXJ within JBoss ............................................. For deployment of Connector/MXJ within a JBoss environment, you must configure the JBoss environment to use the Connector/MXJ component within the JDBC parameters: 1. Download Connector/MXJ and copy the `mysql-connector-mxj-gpl-[ver].jar' file to the `$JBOSS_HOME/server/default/lib' directory. If you are using Connector/MXJ v5.0.4 or later you will also need to copy the `mysql-connector-mxj-gpl-[ver]-db-files.jar' file to `$JBOSS_HOME/server/default/lib'. 2. Download Connector/J and copy the `mysql-connector-java-5.1.5-bin.jar' file to the `$JBOSS_HOME/server/default/lib' directory. 3. Create an MBean service xml file in the `$JBOSS_HOME/server/default/deploy' directory with any attributes set, for instance the `datadir' and `autostart'. 4. Set the JDBC parameters of your web application to use: String driver = "com.mysql.jdbc.Driver"; String url = "jdbc:mysql:///test?propertiesTransform="+ "com.mysql.management.jmx.ConnectorMXJPropertiesTransform"; String user = "root"; String password = ""; Class.forName(driver); Connection conn = DriverManager.getConnection(url, user, password); You may wish to create a separate users and database table spaces for each application, rather than using "root and test". We highly suggest having a routine backup procedure for backing up the database files in the `datadir'.  File: manual.info, Node: connector-mxj-installation-test, Prev: connector-mxj-install-jboss, Up: connector-mxj-install 21.4.3.6 Verifying Installation using JUnit ........................................... * Menu: * connector-mxj-installation-test-requirements:: JUnit Test Requirements * connector-mxj-installation-test-running:: Running the JUnit Tests The best way to ensure that your platform is supported is to run the JUnit tests. These will test the Connector/MXJ classes and the associated components.  File: manual.info, Node: connector-mxj-installation-test-requirements, Next: connector-mxj-installation-test-running, Prev: connector-mxj-installation-test, Up: connector-mxj-installation-test 21.4.3.7 JUnit Test Requirements ................................ The first thing to do is make sure that the components will work on the platform. The MysqldResource class is really a wrapper for a native version of MySQL, so not all platforms are supported. At the time of this writing, Linux on the i386 architecture has been tested and seems to work quite well, as does OS X v10.3. There has been limited testing on Windows and Solaris. Requirements: 1. JDK-1.4 or newer (or the JRE if you aren't going to be compiling the source or JSPs). 2. MySQL Connector/J version 5.0 or newer (from `http://dev.mysql.com/downloads/connector/j/') installed and available using your CLASSPATH. 3. The `javax.management' classes for JMX version 1.2.1, these are present in the following application servers: * JBoss - 4.0rc1 or newer. * Apache Tomcat - 5.0 or newer. * Sun's JMX reference implementation version 1.2.1 (from `http://java.sun.com/products/JavaManagement/'). 4. JUnit 3.8.1 (from `http://www.junit.org/'). If building from source, All of the requirements from above, plus: 1. Ant version 1.5 or newer (download from `http://ant.apache.org/').  File: manual.info, Node: connector-mxj-installation-test-running, Prev: connector-mxj-installation-test-requirements, Up: connector-mxj-installation-test 21.4.3.8 Running the JUnit Tests ................................ 1. The tests attempt to launch MySQL on the port 3336. If you have a MySQL running, it may conflict, but this isn't very likely because the default port for MySQL is 3306. However, You may set the "c-mxj_test_port" Java property to a port of your choosing. Alternatively, you may wish to start by shutting down any instances of MySQL you have running on the target machine. The tests suppress output to the console by default. For verbose output, you may set the "c-mxj_test_silent" Java property to "false". 2. To run the JUnit test suite, the $CLASSPATH must include the following: * JUnit * JMX * Connector/J * MySQL Connector/MXJ 3. If `connector-mxj.jar' is not present in your download, unzip MySQL Connector/MXJ source archive. cd mysqldjmx ant dist Then add `$TEMP/cmxj/stage/connector-mxj/connector-mxj.jar' to the CLASSPATH. 4. If you have `junit', execute the unit tests. From the command line, type: java com.mysql.management.AllTestsSuite The output should look something like this: ......................................... ......................................... .......... Time: 259.438 OK (101 tests) Note that the tests are a bit slow near the end, so please be patient.  File: manual.info, Node: connector-mxj-configuration, Next: connector-mxj-ref, Prev: connector-mxj-install, Up: connector-mxj 21.4.4 Connector/MXJ Configuration ---------------------------------- * Menu: * connector-mxj-configuration-driver-launched:: Running as part of the JDBC Driver * connector-mxj-configuration-java-object:: Running within a Java Object * connector-mxj-configuration-options:: Setting server options  File: manual.info, Node: connector-mxj-configuration-driver-launched, Next: connector-mxj-configuration-java-object, Prev: connector-mxj-configuration, Up: connector-mxj-configuration 21.4.4.1 Running as part of the JDBC Driver ........................................... A feature of the MySQL Connector/J JDBC driver is the ability to specify a connection to an embedded Connector/MXJ instance through the use of the mxj keyword in the JDBC connection string. In the following example, we have a program which creates a connection, executes a query, and prints the result to the System.out. The MySQL database will be deployed and started as part of the connection process, and shutdown as part of the finally block. You can find this file in the Connector/MXJ package as `src/ConnectorMXJUrlTestExample.java'. import java.io.File; import java.sql.Connection; import java.sql.DriverManager; import com.mysql.management.driverlaunched.ServerLauncherSocketFactory; import com.mysql.management.util.QueryUtil; public class ConnectorMXJUrlTestExample { public static String DRIVER = "com.mysql.jdbc.Driver"; public static String JAVA_IO_TMPDIR = "java.io.tmpdir"; public static void main(String[] args) throws Exception { File ourAppDir = new File(System.getProperty(JAVA_IO_TMPDIR)); File databaseDir = new File(ourAppDir, "test-mxj"); int port = Integer.parseInt(System.getProperty("c-mxj_test_port", "3336")); String dbName = "our_test_app"; String url = "jdbc:mysql:mxj://localhost:" + port + "/" + dbName // + "?" + "server.basedir=" + databaseDir // + "&" + "createDatabaseIfNotExist=true"// + "&" + "server.initialize-user=true" // ; System.out.println(url); String userName = "alice"; String password = "q93uti0opwhkd"; Class.forName(DRIVER); Connection conn = null; try { conn = DriverManager.getConnection(url, userName, password); String sql = "SELECT VERSION()"; String queryForString = new QueryUtil(conn).queryForString(sql); System.out.println("------------------------"); System.out.println(sql); System.out.println("------------------------"); System.out.println(queryForString); System.out.println("------------------------"); System.out.flush(); Thread.sleep(100); // wait for System.out to finish flush } finally { try { if (conn != null) conn.close(); } catch (Exception e) { e.printStackTrace(); } ServerLauncherSocketFactory.shutdown(databaseDir, null); } } } To run the above program, be sure to have connector-mxj.jar and Connector/J in the CLASSPATH. Then type: java ConnectorMXJUrlTestExample  File: manual.info, Node: connector-mxj-configuration-java-object, Next: connector-mxj-configuration-options, Prev: connector-mxj-configuration-driver-launched, Up: connector-mxj-configuration 21.4.4.2 Running within a Java Object ..................................... If you have a java application and wish to `embed' a MySQL database, make use of the `com.mysql.management.MysqldResource' class directly. This class may be instantiated with the default (no argument) constructor, or by passing in a java.io.File object representing the directory you wish the server to be "unzipped" into. It may also be instantiated with printstreams for "stdout" and "stderr" for logging. Once instantiated, a `java.util.Map', the object will be able to provide a `java.util.Map' of server options appropriate for the platform and version of MySQL which you will be using. The MysqldResource enables you to "start" MySQL with a `java.util.Map' of server options which you provide, as well as "shutdown" the database. The following example shows a simplistic way to embed MySQL in an application using plain java objects. You can find this file in the Connector/MXJ package as `src/ConnectorMXJObjectTestExample.java'. import java.io.File; import java.sql.Connection; import java.sql.DriverManager; import java.util.HashMap; import java.util.Map; import com.mysql.management.MysqldResource; import com.mysql.management.MysqldResourceI; import com.mysql.management.util.QueryUtil; public class ConnectorMXJObjectTestExample { public static final String DRIVER = "com.mysql.jdbc.Driver"; public static final String JAVA_IO_TMPDIR = "java.io.tmpdir"; public static void main(String[] args) throws Exception { File ourAppDir = new File(System.getProperty(JAVA_IO_TMPDIR)); File databaseDir = new File(ourAppDir, "mysql-mxj"); int port = Integer.parseInt(System.getProperty("c-mxj_test_port", "3336")); String userName = "alice"; String password = "q93uti0opwhkd"; MysqldResource mysqldResource = startDatabase(databaseDir, port, userName, password); Class.forName(DRIVER); Connection conn = null; try { String dbName = "our_test_app"; String url = "jdbc:mysql://localhost:" + port + "/" + dbName // + "?" + "createDatabaseIfNotExist=true"// ; conn = DriverManager.getConnection(url, userName, password); String sql = "SELECT VERSION()"; String queryForString = new QueryUtil(conn).queryForString(sql); System.out.println("------------------------"); System.out.println(sql); System.out.println("------------------------"); System.out.println(queryForString); System.out.println("------------------------"); System.out.flush(); Thread.sleep(100); // wait for System.out to finish flush } finally { try { if (conn != null) { conn.close(); } } catch (Exception e) { e.printStackTrace(); } try { mysqldResource.shutdown(); } catch (Exception e) { e.printStackTrace(); } } } public static MysqldResource startDatabase(File databaseDir, int port, String userName, String password) { MysqldResource mysqldResource = new MysqldResource(databaseDir); Map database_options = new HashMap(); database_options.put(MysqldResourceI.PORT, Integer.toString(port)); database_options.put(MysqldResourceI.INITIALIZE_USER, "true"); database_options.put(MysqldResourceI.INITIALIZE_USER_NAME, userName); database_options.put(MysqldResourceI.INITIALIZE_PASSWORD, password); mysqldResource.start("test-mysqld-thread", database_options); if (!mysqldResource.isRunning()) { throw new RuntimeException("MySQL did not start."); } System.out.println("MySQL is running."); return mysqldResource; } }  File: manual.info, Node: connector-mxj-configuration-options, Prev: connector-mxj-configuration-java-object, Up: connector-mxj-configuration 21.4.4.3 Setting server options ............................... Of course there are many options we may wish to set for a MySQL database. These options may be specified as part of the JDBC connection string simply by prefixing each server option with `server.'. In the following example we set two driver parameters and two server parameters: String url = "jdbc:mysql://" + hostColonPort + "/" + "?" + "cacheServerConfiguration=true" + "&" + "useLocalSessionState=true" + "&" + "server.basedir=/opt/myapp/db" + "&" + "server.datadir=/mnt/bigdisk/myapp/data"; Starting with Connector/MXJ 5.0.6 you can use the `initialize-user' property to a connection string. If set to true, the default anonymous and root users will be removed and the user/password combination from the connection URL will be used to create a new user. For example: String url = "jdbc:mysql:mxj://localhost:" + port + "/alice_db" + "?server.datadir=" + dataDir.getPath() + "&server.initialize-user=true" + "&createDatabaseIfNotExist=true" ;  File: manual.info, Node: connector-mxj-ref, Next: connector-mxj-usagenotes, Prev: connector-mxj-configuration, Up: connector-mxj 21.4.5 Connector/MXJ Reference ------------------------------ * Menu: * connector-mxj-ref-mysqldresource-ctor:: MysqldResource Constructors * connector-mxj-ref-mysqldresource-methods:: MysqldResource Methods The following sections include detailed information on the different API interfaces to Connector/MXJ.  File: manual.info, Node: connector-mxj-ref-mysqldresource-ctor, Next: connector-mxj-ref-mysqldresource-methods, Prev: connector-mxj-ref, Up: connector-mxj-ref 21.4.5.1 MysqldResource Constructors .................................... The `MysqldResource' class supports three different constructor forms: * `public MysqldResource(File baseDir, File dataDir, String mysqlVersionString, PrintStream out, PrintStream err)' Enables you to set the base directory, data directory, select a server by its version string, standard out and standard error. * `public MysqldResource(File baseDir, File dataDir, String mysqlVersionString) ' Enables you to set the base directory, data directory and select a server by its version string. Output for standard out and standard err are directed to System.out and System.err. * `public MysqldResource(File baseDir, File dataDir) ' Enables you to set the base directory and data directory. The default MySQL version is selected, and output for standard out and standard err are directed to System.out and System.err. * `public MysqldResource(File baseDir);' Enables the setting of the "basedir" to deploy the MySQL files to. Output for standard out and standard err are directed to System.out and System.err. * `public MysqldResource();' The basedir is defaulted to a subdirectory of the java.io.tempdir. Output for standard out and standard err are directed to System.out and System.err;  File: manual.info, Node: connector-mxj-ref-mysqldresource-methods, Prev: connector-mxj-ref-mysqldresource-ctor, Up: connector-mxj-ref 21.4.5.2 MysqldResource Methods ............................... MysqldResource API includes the following methods: * `void start(String threadName, Map mysqldArgs);' Deploys and starts MySQL. The "threadName" string is used to name the thread which actually performs the execution of the MySQL command line. The map is the set of arguments and their values to be passed to the command line. * `void shutdown(); ' Shuts down the MySQL instance managed by the MysqldResource object. * ` Map getServerOptions(); ' Returns a map of all the options and their current (or default, if not running) options available for the MySQL database. * ` boolean isRunning(); ' Returns true if the MySQL database is running. * ` boolean isReadyForConnections(); ' Returns true once the database reports that is ready for connections. * ` void setKillDelay(int millis); ' The default `Kill Delay' is 30 seconds. This represents the amount of time to wait between the initial request to shutdown and issuing a `force kill' if the database has not shutdown by itself. * ` void addCompletionListenser(Runnable listener); ' Enables applications to be notified when the server process completes. Each `listener' will be fired off in its own thread. * ` String getVersion(); ' Returns the version of MySQL. * ` void setVersion(int MajorVersion, int minorVersion, int patchLevel); ' The standard distribution comes with only one version of MySQL packaged. However, it is possible to package multiple versions, and specify which version to use.  File: manual.info, Node: connector-mxj-usagenotes, Next: connector-mxj-samples, Prev: connector-mxj-ref, Up: connector-mxj 21.4.6 Connector/MXJ Notes and Tips ----------------------------------- * Menu: * connector-mxj-usagenotes-packaging:: Creating your own Connector/MXJ Package * connector-mxj-usagenotes-customdb:: Deploying Connector/MXJ with a pre-configured database * connector-mxj-usagenotes-jmx-agent:: Running within a JMX Agent (custom) * connector-mxj-usagenotes-standard-environment:: Deployment in a standard JMX Agent environment (JBoss) This section contains notes and tips on using the Connector/MXJ component within your applications.  File: manual.info, Node: connector-mxj-usagenotes-packaging, Next: connector-mxj-usagenotes-customdb, Prev: connector-mxj-usagenotes, Up: connector-mxj-usagenotes 21.4.6.1 Creating your own Connector/MXJ Package ................................................ If you want to create a custom Connector/MXJ package that includes a specific `mysqld' version or platform then you must extract and rebuild the `mysql-connector-mxj.jar' (Connector/MXJ v5.0.3 or earlier) or `mysql-connector-mxj-gpl-[ver]-db-files.jar' (Connector/MXJ v5.0.4 or later) file. First, you should create a new directory into which you can extract the current `connector-mxj.jar': shell> mkdir custom-mxj shell> cd custom-mxj shell> jar -xf connector-mxj.jar shell> ls 5-0-22/ ConnectorMXJObjectTestExample.class ConnectorMXJUrlTestExample.class META-INF/ TestDb.class com/ kill.exe If you are using Connector/MXJ v5.0.4 or later, you should unpack the `connector-mxj-db-files.jar': shell> mkdir custom-mxj shell> cd custom-mxj shell> jar -xf connector-mxj-db-files.jar shell> ls 5-0-51a/ META-INF/ connector-mxj.properties The MySQL version directory, `5-0-22' or `5-0-51a' in the preceding examples, contains all of the files used to create an instance of MySQL when Connector/MXJ is executed. All of the files in this directory are required for each version of MySQL that you want to embed. Note as well the format of the version number, which uses hyphens instead of periods to separate the version number components. Within the version specific directory are the platform specific directories, and archives of the `data' and `share' directory required by MySQL for the various platforms. For example, here is the listing for the default Connector/MXJ package: shell>> ls Linux-i386/ META-INF/ Mac_OS_X-ppc/ SunOS-sparc/ Win-x86/ com/ data_dir.jar share_dir.jar win_share_dir.jar Platform specific directories are listed by their OS and platform - for example the `mysqld' for Mac OS X PowerPC is located within the `Mac_OS_X-ppc' directory. You can delete directories from this location that you do not require, and add new directories for additional platforms that you want to support. To add a platform specific `mysqld', create a new directory with the corresponding name for your operating system/platform. For example, you could add a directory for Mac OS X/Intel using the directory `Mac_OS_X-i386'. On Unix systems, you can determine the platform using `uname': shell> uname -p i386 In Connector/MXJ v5.0.9 and later, an additional `platform-map.properties' file is used to associate a specific platform and operating system combination with the directory in which the `mysqld' for that combination is located. The determined operating system and platform are on the left, and the directory name where the appropriate mysqld is located is on the right. You can see a sample of the file below: Linux-i386=Linux-i386 Linux-x86=Linux-i386 Linux-i686=Linux-i386 Linux-x86_64=Linux-i386 Linux-ia64=Linux-i386 #Linux-ppc=Linux-ppc #Linux-ppc64=Linux-ppc Mac_OS_X-i386=Mac_OS_X-i386 Mac_OS_X-ppc=Mac_OS_X-ppc Rhapsody-PowerPC=Mac_OS_X-ppc #Mac_OS-PowerPC= #macos-PowerPC= #MacOS-PowerPC= SunOS-sparc=SunOS-sparc Solaris-sparc=SunOS-sparc SunOS-x86=SunOS-x86 Solaris-x86=SunOS-x86 FreeBSD-x86=FreeBSD-x86 Windows_Vista-x86=Win-x86 Windows_2003-x86=Win-x86 Windows_XP-x86=Win-x86 Windows_2000-x86=Win-x86 Windows_NT-x86=Win-x86 Windows_NT_(unknown)-x86=Win-x86 Now you need to download or compile `mysqld' for the MySQL version and platform you want to include in your custom `connector-mxj.jar' package into the new directory. Create a file called `version.txt' in the OS/platform directory you have just created that contains the version string/path of the mysqld binary. For example: mysql-5.0.22-osx10.3-i386/bin/mysqld You can now recreate the `connector-mxj.jar' file with the added `mysqld': shell> cd custom-mxj shell> jar -cf ../connector-mxj.jar * For Connector/MXJ v5.0.4 and later, you should repackage to the `connector-mxj-db-files.jar': shell> cd custom-mxj shell> jar -cf ../mysql-connector-mxj-gpl-[ver]-db-files.jar * You should test this package using the steps outlined in *Note connector-mxj-install-quickstart::. *Note*: Because the `mysql-connector-mxj-gpl-[ver]-db-files.jar' file is separate from the main Connector/MXJ classes you can distribute different `mysql-connector-mxj-gpl-[ver]-db-files.jar' files to different hosts or for different projects without having to create a completely new main `mysql-connector-mxj-gpl-[ver].jar' file for each one.  File: manual.info, Node: connector-mxj-usagenotes-customdb, Next: connector-mxj-usagenotes-jmx-agent, Prev: connector-mxj-usagenotes-packaging, Up: connector-mxj-usagenotes 21.4.6.2 Deploying Connector/MXJ with a pre-configured database ............................................................... To include a pre-configured/populated database within your Connector/MXJ JAR file you must create a custom `data_dir.jar' file, as included within the main `connector-mxj.jar' (Connector/MXJ 5.0.3 or earlier) or `mysql-connector-mxj-gpl-[ver]-db-files.jar' (Connector/MXJ 5.0.4 or later) file: 1. First extract the `connector-mxj.jar' or `mysql-connector-gpl-[ver]-db-files.jar' file, as outlined in the previous section (see *Note connector-mxj-usagenotes-packaging::). 2. First, create your database and populate the database with the information you require in an existing instance of MySQL - including Connector/MXJ instances. Data file formats are compatible across platforms. 3. Shutdown the instance of MySQL. 4. Create a JAR file of the data directory and databases that you want to include your Connector/MXJ package. You should include the `mysql' database, which includes user authentication information, in addition to the specific databases you want to include. For example, to create a JAR of the `mysql' and `mxjtest' databases: shell> jar -cf ../data_dir.jar mysql mxjtest 5. For Connector/MXJ 5.0.3 or earlier, copy the `data_dir.jar' file into the extracted `connector-mxj.jar' directory, and then create an archive for `connector-mxj.jar'. For Connector/MXJ 5.0.4 or later, copy the `data_dir.jar' file into the extracted `mysql-connector-mxj-gpl-[ver]-db-files.jar' directory, and then create an archive for `mysql-connector-mxj-db-gpl-[ver]--files.jar'. Note that if you are create databases using the InnoDB engine, you must include the `ibdata.*' and `ib_logfile*' files within the `data_dir.jar' archive.  File: manual.info, Node: connector-mxj-usagenotes-jmx-agent, Next: connector-mxj-usagenotes-standard-environment, Prev: connector-mxj-usagenotes-customdb, Up: connector-mxj-usagenotes 21.4.6.3 Running within a JMX Agent (custom) ............................................ As a JMX MBean, MySQL Connector/MXJ requires a JMX v1.2 compliant MBean container, such as JBoss version 4. The MBean will uses the standard JMX management APIs to present (and allow the setting of) parameters which are appropriate for that platform. If you are not using the SUN Reference implementation of the JMX libraries, you should skip this section. Or, if you are deploying to JBoss, you also may wish to skip to the next section. We want to see the MysqldDynamicMBean in action inside of a JMX agent. In the `com.mysql.management.jmx.sunri' package is a custom JMX agent with two MBeans: 1. The MysqldDynamicMBean, and 2. A com.sun.jdmk.comm.HtmlAdaptorServer, which provides a web interface for manipulating the beans inside of a JMX agent. When this very simple agent is started, it will allow a MySQL database to be started and stopped with a web browser. 1. Complete the testing of the platform as above. * Current JDK, JUnit, Connector/J, MySQL Connector/MXJ * This section _requires_ the SUN reference implementation of JMX * `PATH', `JAVA_HOME', `ANT_HOME', `CLASSPATH' 2. If not building from source, skip to next step Rebuild with the "sunri.present" ant -Dsunri.present=true dist re-run tests: java junit.textui.TestRunner com.mysql.management.AllTestsSuite 3. Launch the test agent from the command line: java com.mysql.management.jmx.sunri.MysqldTestAgentSunHtmlAdaptor & 4. From a browser: http://localhost:9092/ 5. Under MysqldAgent, select "name=mysqld" 6. Observe the MBean View 7. Scroll to the bottom of the screen press the `startMysqld' button 8. Click `Back to MBean View' 9. Scroll to the bottom of the screen press `stopMysqld' button 10. Kill the java process running the Test Agent (jmx server)  File: manual.info, Node: connector-mxj-usagenotes-standard-environment, Prev: connector-mxj-usagenotes-jmx-agent, Up: connector-mxj-usagenotes 21.4.6.4 Deployment in a standard JMX Agent environment (JBoss) ............................................................... Once there is confidence that the MBean will function on the platform, deploying the MBean inside of a standard JMX Agent is the next step. Included are instructions for deploying to JBoss. 1. Ensure a current version of java development kit (v1.4.x), see above. * Ensure `JAVA_HOME' is set (JBoss requires `JAVA_HOME') * Ensure `JAVA_HOME/bin' is in the `PATH' (You will NOT need to set your CLASSPATH, nor will you need any of the jars used in the previous tests). 2. Ensure a current version of JBoss (v4.0RC1 or better) http://www.jboss.org/index.html select "Downloads" select "jboss-4.0.zip" pick a mirror unzip ~/dload/jboss-4.0.zip create a JBOSS_HOME environment variable set to the unzipped directory unix only: cd $JBOSS_HOME/bin chmod +x *.sh 3. Deploy (copy) the `connector-mxj.jar' to `$JBOSS_HOME/server/default/lib'. 4. Deploy (copy) `mysql-connector-java-3.1.4-beta-bin.jar' to `$JBOSS_HOME/server/default/lib'. 5. Create a `mxjtest.war' directory in `$JBOSS_HOME/server/default/deploy'. 6. Deploy (copy) `index.jsp' to `$JBOSS_HOME/server/default/deploy/mxjtest.war'. 7. Create a `mysqld-service.xml' file in `$JBOSS_HOME/server/default/deploy'. /tmp/xxx_data_xxx true 8. Start jboss: * On unix: `$JBOSS_HOME/bin/run.sh' * On windows: `%JBOSS_HOME%\bin\run.bat' Be ready: JBoss sends a lot of output to the screen. 9. When JBoss seems to have stopped sending output to the screen, open a web browser to: `http://localhost:8080/jmx-console' 10. Scroll down to the bottom of the page in the `mysql' section, select the bulleted `mysqld' link. 11. Observe the JMX MBean View page. MySQL should already be running. 12. (If "autostart=true" was set, you may skip this step.) Scroll to the bottom of the screen. You may press the `Invoke' button to stop (or start) MySQL observe `Operation completed successfully without a return value.' Click `Back to MBean View' 13. To confirm MySQL is running, open a web browser to `http://localhost:8080/mxjtest/' and you should see that SELECT 1 returned with a result of 1 14. Guided by the `$JBOSS_HOME/server/default/deploy/mxjtest.war/index.jsp' you will be able to use MySQL in your Web Application. There is a `test' database and a `root' user (no password) ready to experiment with. Try creating a table, inserting some rows, and doing some selects. 15. Shut down MySQL. MySQL will be stopped automatically when JBoss is stopped, or: from the browser, scroll down to the bottom of the MBean View press the stop service `Invoke' button to halt the service. Observe `Operation completed successfully without a return value.' Using `ps' or `task manager' see that MySQL is no longer running As of 1.0.6-beta version is the ability to have the MBean start the MySQL database upon start up. Also, we've taken advantage of the JBoss life-cycle extension methods so that the database will gracefully shut down when JBoss is shutdown.  File: manual.info, Node: connector-mxj-samples, Next: connector-mxj-support, Prev: connector-mxj-usagenotes, Up: connector-mxj 21.4.7 Connector/MXJ Samples ---------------------------- * Menu: * connector-mxj-samples-jsp:: Using Connector/MXJ with JSP This section contains some sample applications using Connector/MXJ.  File: manual.info, Node: connector-mxj-samples-jsp, Prev: connector-mxj-samples, Up: connector-mxj-samples 21.4.7.1 Using Connector/MXJ with JSP ..................................... The following web application was provided by Pavan Venkatesh as an example of a JSP based application using Connector/MXJ to provide contact data. The example consists of two components, `insertdata.jsp' and `response.jsp'. The `insertdata.jsp' provides a form into which you can enter information to be stored within the MySQL database provided by Connector/MXJ. The `response.jsp' file is called when you submit the form and then provides a table of the data. Because the data is stored through Connector/MXJ the instantiation of the MySQL database is handled dynamically on the fly, making the script lightweight and self-contained. <%@page contentType="text/html" pageEncoding="UTF-8"%> <%@ page import="java.sql.*"%> <%@ page import="java.io.*"%> <%@ page import="java.io.*"%> <%@ page import="java.sql.*"%> insert data

Welcome to MySQL world

MySQL with MXJ Connection

Insert data in existing "contactdetails2009" table under "Directory" database

ID
Name
City
Phone
<%@ page import="java.sql.*"%> <%@ page import="java.sql.*"%> <%@ page import="java.io.*"%> <%@ page import="java.io.*"%> <%@ page import="java.sql.*"%> <%@ page import="java.sql.Connection"%> <%@ page import="java.sql.DriverManager"%> <%@ page language="java"%> <%@ page import=" com.mysql.management.util.QueryUtil"%> <%@page contentType="text/html" pageEncoding="UTF-8"%> JSP Page

Welcome to Directory Database

<% String ID = request.getParameter("ID"); String name = request.getParameter("names"); String city = request.getParameter("place"); String phone = request.getParameter("phone"); File ourAppDir1 = new File("/tmp/src"); File databaseDir1 = new File(ourAppDir1,"database"); int port = 4336; String dbName = "Directory"; try { String url = "jdbc:mysql:mxj://localhost:" + port + "/" + dbName // + "?" + "server.basedir=" + databaseDir1 // + "&" + "createDatabaseIfNotExist=true"// + "&" + "server.initialize-user=true" // ; Connection connection = null; int updateQuery=0; Class.forName("com.mysql.jdbc.Driver").newInstance(); String userName = "alice"; String password = "q93uti0opwhkd"; connection = DriverManager.getConnection(url, userName, password); PreparedStatement pstatement = null; String sql = "SELECT VERSION()"; String queryForString = new QueryUtil(connection).queryForString(sql); String command = "INSERT INTO contactdetails2009 (ID, name,city,phone) VALUES (?,?,?,?)"; pstatement = connection.prepareStatement(command); pstatement.setString(1, ID); pstatement.setString(2, name); pstatement.setString(3, city); pstatement.setString(4, phone); updateQuery = pstatement.executeUpdate(); ResultSet resultset = pstatement.executeQuery("select * from contactdetails2009"); if (updateQuery != 0) { %>

MySQL Version------------> <% out.println(queryForString); %>

Data successfully inserted into MySQL database using MXJ connection
Storage Engine used is MyISAM

ContactDetails2009 Table

<% while(resultset.next()){ %> <% } %> <% resultset.close(); pstatement.close(); connection.close(); } } catch (Exception e) { %>
ID name city phone
<%= resultset.getString(1) %> <%= resultset.getString(2) %> <%= resultset.getString(3) %> <%= resultset.getString(4) %>
ERROR------------> <% out.println("ID or Row already exist"); } %>
 File: manual.info, Node: connector-mxj-support, Prev: connector-mxj-samples, Up: connector-mxj 21.4.8 Connector/MXJ Support ---------------------------- * Menu: * connector-mxj-support-community:: Connector/MXJ Community Support * connector-mxj-support-bug-report:: How to Report Connector/MXJ Problems * connector-mxj-support-changelog:: Connector/MXJ Change History There are a wide variety of options available for obtaining support for using Connector/MXJ. You should contact the Connector/MXJ community for help before reporting a potential bug or problem. See *Note connector-mxj-support-community::.  File: manual.info, Node: connector-mxj-support-community, Next: connector-mxj-support-bug-report, Prev: connector-mxj-support, Up: connector-mxj-support 21.4.8.1 Connector/MXJ Community Support ........................................ Oracle provides assistance to the user community by means of a number of mailing lists and web based forums. You can find help and support through the MySQL and Java (http://lists.mysql.com/java) mailing list. For information about subscribing to MySQL mailing lists or to browse list archives, visit `http://lists.mysql.com/'. See *Note mailing-lists::. Community support from experienced users is also available through the MyODBC Forum (http://forums.mysql.com/list.php?39). You may also find help from other users in the other MySQL Forums, located at `http://forums.mysql.com'. See *Note forums::.  File: manual.info, Node: connector-mxj-support-bug-report, Next: connector-mxj-support-changelog, Prev: connector-mxj-support-community, Up: connector-mxj-support 21.4.8.2 How to Report Connector/MXJ Problems ............................................. If you encounter difficulties or problems with Connector/MXJ, contact the Connector/MXJ community *Note connector-mxj-support-community::. If reporting a problem, you should ideally include the following information with the email: * Operating system and version * Connector/MXJ version * MySQL server version * Copies of error messages or other unexpected output * Simple reproducible sample Remember that the more information you can supply to us, the more likely it is that we can fix the problem. If you believe the problem to be a bug, then you must report the bug through `http://bugs.mysql.com/'.  File: manual.info, Node: connector-mxj-support-changelog, Prev: connector-mxj-support-bug-report, Up: connector-mxj-support 21.4.8.3 Connector/MXJ Change History ..................................... The Connector/MXJ Change History (Changelog) is located with the main Changelog for MySQL. See *Note news-connector-mxj::.  File: manual.info, Node: connector-cpp, Next: connector-c, Prev: connector-mxj, Up: connectors-apis 21.5 MySQL Connector/C++ ======================== * Menu: * connector-cpp-installation-binary:: MySQL Connector/C++ Binary Installation * connector-cpp-installation-source:: MySQL Connector/C++ Source Installation * connector-cpp-apps-windows-visual-studio:: MySQL Connector/C++ Building Windows applications with Microsoft Visual Studio * connector-cpp-apps-linux-netbeans:: MySQL Connector/C++ Building Linux applications with NetBeans * connector-cpp-getting-started-examples:: MySQL Connector/C++ Getting Started: Usage Examples * connector-cpp-tutorials:: MySQL Connector/C++ Tutorials * connector-cpp-debug-tracing:: MySQL Connector/C++ Debug Tracing * connector-cpp-usage-notes:: MySQL Connector/C++ Usage Notes * connector-cpp-bugs:: MySQL Connector/C++ Known Bugs and Issues * connector-cpp-requests:: MySQL Connector/C++ Feature requests * connector-cpp-support:: MySQL Connector/C++ Support * connector-cpp-faq:: MySQL Connector/C++ FAQ MySQL Connector/C++ is a MySQL database connector for C++. The MySQL Connector/C++ is licensed under the terms of the GPL, like most MySQL Connectors. There are special exceptions to the terms and conditions of the GPL as it is applied to this software, see FLOSS License Exception. If you need a non-GPL license for commercial distribution please contact us. The MySQL Connector/C++ is compatible with the JDBC 4.0 API. However, MySQL Connector/C++ does not implement all of the JDBC 4.0 API. The MySQL Connector/C++ current version features the following classes: * Connection * DatabaseMetaData * Driver * PreparedStatement * ResultSet * ResultSetMetaData * Savepoint * Statement The JDBC 4.0 API defines approximately 450 methods for the above mentioned classes. MySQL Connector/C++ implements around 80% of these and makes them available in the current release. The release has been successfully compiled and tested on the following platforms: *AIX* * 5.2 (PPC32, PPC64) * 5.3 (PPC32, PPC64) *FreeBSD* * 6.0 (x86, x86_64) *HPUX* * 11.11 (PA-RISC 32bit, PA-RISC 64bit) *Linux* * Debian 3.1 (PPC32, x86) * FC4 (x86) * RHEL 3 (ia64, x86, x86_64) * RHEL 4 (ia64, x86, x86_64) * RHEL 5 (ia64, x86, x86_64) * SLES 9 (ia64, x86, x86_64) * SLES 10 (ia64, x86_64) * SuSE 10.3, (x86_64) * Ubuntu 8.04 (x86) * Ubuntu 8.10 (x86_64) *Mac* * MacOSX 10.3 (PPC32, PPC64) * MacOSX 10.4 (PPC32, PPC64, x86) * MacOSX 10.5 (PPC32, PPC64, x86, x86_64) *SunOS* * Solaris 8 (SPARC32, SPARC64, x86) * Solaris 9 (SPARC32, SPARC64, x86) * Solaris 10 (SPARC32, SPARC64, x86, x86_64) *Windows* * XP Professional (32bit) * 2003 (64bit) Future versions will run on all platforms supported by the MySQL Server. *Note*: MySQL Connector/C++ supports MySQL 5.1 and later. *Note*: MySQL Connector/C++ supports only Microsoft Visual Studio 2003 and above on Windows. *MySQL Connector/C++ Download* You can download the source code for the MySQL Connector/C++ current release at the MySQL Connector/C++ downloads (http://dev.mysql.com/downloads/connector/cpp/). *MySQL Connector/C++ Source repository* The latest development version is also available through Launchpad (https://launchpad.net/mysql-connector-cpp). Bazaar is used for the MySQL Connector/C++ code repository. You can check out the latest source code using the `bzr' command line tool: shell> bzr branch lp:~mysql/mysql-connector-cpp/trunk . *Binary distributions* Starting with 1.0.4 Beta, binary distributions were made available in addition to source code releases. The releases available are shown below. Microsoft Windows platform: * Without installer, a Zip file * MSI installer package Other platforms: * Compressed GNU TAR archive (tar.gz) *Note*: Note that source packages are available for all platforms in the Compressed GNU TAR archive (tar.gz) format. Binary and source packages can be obtained from MySQL Connector/C++ downloads (http://dev.mysql.com/downloads/connector/cpp/). *MySQL Connector/C++ Advantages* Using MySQL Connector/C++ instead of the MySQL C API (MySQL Client Library) offers the following advantages for C++ users: * Convenience of pure C++, no C function calls required * Supports an industry standard API, JDBC 4.0 * Supports the object-oriented programming paradigm * Reduces development time * MySQL Connector/C++ is licensed under the GPL with the FLOSS License Exception * MySQL Connector/C++ is available under a commercial license upon request *MySQL Connector/C++ Status* MySQL Connector/C++ is available as a GA version. We kindly ask users and developers to try it out and provide us with feedback. Note that MySQL Workbench is successfully using MySQL Connector/C++. If you have any queries please *Note contact us: connector-cpp-support.  File: manual.info, Node: connector-cpp-installation-binary, Next: connector-cpp-installation-source, Prev: connector-cpp, Up: connector-cpp 21.5.1 MySQL Connector/C++ Binary Installation ---------------------------------------------- *Caution*: One problem that can occur is when the tools you use to build your application are not compatible with the tools used to build the binary versions of MySQL Connector/C++. Ideally you need to build your application with the same tools that were used to build the MySQL Connector/C++ binaries. To help with this the following resources are provided. All distributions contain a `README' file, which contains platform-specific notes. At the end of the `README' file contained in the binary distribution you will find the settings used to build the binaries. If you experience build-related issues on a platform, it may help to check the settings used on the platform to build the binary. Developers using Microsoft Windows need to ensure they meet the following requirements: 1. Use a supported version of Visual Studio, either Visual Studio 2005 or Visual Studio 2008. 2. Ensure that your application uses the same run time library as that used to build MySQL Connector/C++. Visual Studio 2005 builds use Microsoft.VC80.CRT (8.0.50727.762), and Visual Studio 2008 builds use Microsoft.VC90.CRT (9.0.21022.8). 3. Your application should use the same linker configuration as MySQL Connector/C++, for example use one of /MD, /MDd, /MT, /MTd. If you wish to use a variation of the requirements previously listed, such as a different compiler version, release configuration, or run time library, you must compile MySQL Connector/C++ from source using your desired settings, and then ensure that your application is built with these same settings. The three variables of compiler version, run time library, and run time linker configuration settings should always be the same for both application and MySQL Connector/C++ itself, in order to avoid issues. For your convenience the same information, but more frequently updated, can be found on the MySQL Forge site (http://forge.mysql.com/wiki/Connector_C%2B%2B_Binary_Builds). A better solution is to build your MySQL Connector/C++ libraries from the source code, using the same tools that you use for building your application. This ensures compatibility. *Downloading MySQL Connector/C++* Binary and source packages can be obtained from MySQL Connector/C++ downloads (http://dev.mysql.com/downloads/connector/cpp/). *Archive Package* Unpack the archive into an appropriate directory. If you plan to use a dynamically linked version of MySQL Connector/C++, make sure that your system can reference the MySQL Client Library. Consult your operating system documentation on how do modify and expand the search path for libraries. In case you cannot modify the library search path it may help to copy your application, the MySQL Connector/C++ library and the MySQL Client Library into the same directory. Most systems search for libraries in the current directory. *Windows MSI Installer* Windows users can choose between two binary packages: 1. Without installer (unzip in C:\) 2. Windows MSI Installer (x86) Using the MSI Installer may be the easiest solution. Running the MSI Installer does not require any administrative permissions as it simply copies files. FIGURE GOES HERE: Windows Installer Welcome Screen FIGURE GOES HERE: Windows Installer Overview Screen The `Typical' installation consists of all required header files and the Release libraries. The only available `Custom' installation option enables you to install additional Debug versions of the connector libraries. FIGURE GOES HERE: Windows Installer Custom Setup Screen  File: manual.info, Node: connector-cpp-installation-source, Next: connector-cpp-apps-windows-visual-studio, Prev: connector-cpp-installation-binary, Up: connector-cpp 21.5.2 MySQL Connector/C++ Source Installation ---------------------------------------------- * Menu: * connector-cpp-installation-source-unix:: Building source on Unix, Solaris and Mac OS X * connector-cpp-installation-source-windows:: Building source on Windows * connector-cpp-dynamic-linking-client-library:: Dynamically Linking MySQL Connector/C++ against the MySQL Client Library The MySQL Connector/C++ is based on the MySQL Client Library (MySQL C API). MySQL Connector/C++ is linked against the MySQL Client Library. You need to have the MySQL Client Library installed to compile MySQL Connector/C++. You also need to have the cross-platform build tool `CMake' 2.4, or newer, and GLib 2.2.3 or newer installed. Check the `README' file included with the distribution for platform specific notes on building for Windows and SunOS. Typically the MySQL Client Library is installed when the MySQL Server is installed. However, check your operating system documentation for other installation options. As of MySQL Connector/C++ version 1.1.0 it is necessary to have the Boost C++ libraries 1.34.0 or newer installed. Boost is only required to build the connector, it is not required to use the connector. You can obtain Boost from the official site (http://www.boost.org) and installation instructions can be obtained from the same site. Once Boost has been installed you will need to tell the make system where the Boost files are. This is done by setting the define `-DBOOST_ROOT:STRING='. This can be done when initially invoking `CMake', for example: shell> CMake . -DBOOST_ROOT:STRING=/usr/local/boost_1_40_0 You may need to change /USR/LOCAL/BOOST_1_40_0/ to match your installation. See the *Note connector-cpp-installation-source-unix:: and *Note connector-cpp-installation-source-windows:: for further details.  File: manual.info, Node: connector-cpp-installation-source-unix, Next: connector-cpp-installation-source-windows, Prev: connector-cpp-installation-source, Up: connector-cpp-installation-source 21.5.2.1 Building source on Unix, Solaris and Mac OS X ...................................................... 1. Run `CMake' to build a `Makefile': shell> me@host:/path/to/mysql-connector-cpp> cmake . -- Check for working C compiler: /usr/local/bin/gcc -- Check for working C compiler: /usr/local/bin/gcc -- works [...] -- Generating done -- Build files have been written to: /path/to/mysql-connector-cpp/ On non-Windows systems, `CMake' first checks to see if the `CMake' variable `MYSQL_CONFIG_EXECUTABLE' is set. If it is not found `CMake' tries to locate `mysql_config' in the default locations. If you have any problems with the configure process please check the troubleshooting instructions below. 2. Use make to build the libraries. First make sure you have a clean build: shell> me@host:/path/to/mysql-connector-cpp> make clean Then build the connector: me@host:/path/to/mysql-connector-cpp> make [ 1%] Building CXX object » driver/CMakeFiles/mysqlcppconn.dir/mysql_connection.o [ 3%] Building CXX object » driver/CMakeFiles/mysqlcppconn.dir/mysql_constructed_resultset.o [...] [100%] Building CXX object examples/CMakeFiles/statement.dir/statement.o Linking CXX executable statement If all goes well, you will find the MySQL Connector/C++ library in `/path/to/cppconn/libmysqlcppconn.so'. 3. Finally make sure the header and library files are installed to their correct locations: make install Unless you have changed this in the configuration step, the header files will be copied to the directory `/usr/local/include'. The header files copied are `mysql_connection.h' and `mysql_driver.h'. Again, unless you have specified otherwise, the library files will be copied to `/usr/local/lib'. The files copied are `libmysqlcppcon.so', the dynamic library, and `libmysqlcppconn-static.a', the static library. If you encounter any errors, please first carry out the checks shown below: 1. `CMake' options: MySQL installation path, debug version and more In case of configuration or compilation problems, check the list of `CMake' options: shell> me@host:/path/to/mysql-connector-cpp> cmake -L [...] CMAKE_BACKWARDS_COMPATIBILITY:STRING=2.4 CMAKE_BUILD_TYPE:STRING= CMAKE_INSTALL_PREFIX:PATH=/usr/local EXECUTABLE_OUTPUT_PATH:PATH= LIBRARY_OUTPUT_PATH:PATH= MYSQLCPPCONN_GCOV_ENABLE:BOOL=0 MYSQLCPPCONN_TRACE_ENABLE:BOOL=0 MYSQL_CONFIG_EXECUTABLE:FILEPATH=/usr/bin/mysql_config For example, if your MySQL Server installation path is not `/usr/local/mysql' and you want to build a debug version of the MySQL Connector/C++ use: shell> me@host:/path/to/mysql-connector-cpp> cmake » -D CMAKE_BUILD_TYPE:STRING=Debug » -D MYSQL_CONFIG_EXECUTABLE=/path/to/my/mysql/server/bin/mysql_config . 2. Verify your settings with `cmake `-L'': shell> me@host:/path/to/mysql-connector-cpp> cmake -L [...] CMAKE_BACKWARDS_COMPATIBILITY:STRING=2.4 CMAKE_BUILD_TYPE:STRING= CMAKE_INSTALL_PREFIX:PATH=/usr/local EXECUTABLE_OUTPUT_PATH:PATH= LIBRARY_OUTPUT_PATH:PATH= MYSQLCPPCONN_GCOV_ENABLE:BOOL=0 MYSQLCPPCONN_TRACE_ENABLE:BOOL=0 MYSQL_CONFIG_EXECUTABLE=/path/to/my/mysql/server/bin/mysql_config Proceed by carrying out a `make clean' command followed by a `make' command, as described above. Once you have installed MySQL Connector/C++ you can carry out a quick test to check the installation. To do this you can compile and run one of the example programs, such as `examples/standalone_example.cpp'. This example is discussed in more detail later, but for now you can use it to test the connector has been correctly installed. This procedure assumes you have a working MySQL Server that you can connect to. 1. First compile the example. To do this change to the `examples' directory and type: shell> g++ -o test_install -I/usr/local/include -I/usr/local/include/cppconn -Wl,-Bdynamic -lmysqlcppconn standalone_example.cpp 2. You need to make sure the dynamic library which is used in this case can be found at run time. To do this enter: shell> export LD_LIBRARY_PATH=/usr/local/lib 3. Now run the program to test your installation, exchanging the host, user, password and database to be accessed given below to match your system: ./test_install localhost root password database You will see something similar to the following: Connector/C++ standalone program example... ... running 'SELECT 'Welcome to Connector/C++' AS _message' ... MySQL replies: Welcome to Connector/C++ ... say it again, MySQL ....MySQL replies: Welcome to Connector/C++ ... find more at http://www.mysql.com If you see any errors take note of them and go through the troubleshooting procedures discussed earlier.  File: manual.info, Node: connector-cpp-installation-source-windows, Next: connector-cpp-dynamic-linking-client-library, Prev: connector-cpp-installation-source-unix, Up: connector-cpp-installation-source 21.5.2.2 Building source on Windows ................................... *Note*: Please note the only compiler formally supported for Windows is Microsoft Visual Studio 2003 and above. The basic steps for building the connector on Windows are the same as for Unix. It is important to use `CMake' 2.6.2 or newer to generate build files for your compiler and to invoke the compiler. *Note*: On Windows, `mysql_config' is not present, so `CMake' will attempt to retrieve the location of MySQL from the environment variable `$ENV{MYSQL_DIR}'. If `MYSQL_DIR' is not set, `CMake' will then proceed to check for MySQL in the following locations: `$ENV{ProgramFiles}/MySQL/*/include', and `$ENV{SystemDrive}/MySQL/*/include'. `CMake' makes it easy for you to try other compilers. However, you may experience compile warnings, compile errors or linking issues not detected by Visual Studio. Patches are gratefully accepted to fix issues with other compilers. Consult the `CMake' manual or check `cmake --help' to find out which build systems are supported by your `CMake' version: C:\>cmake --help cmake version 2.6-patch 2 Usage [...] Generators The following generators are available on this platform: Borland Makefiles = Generates Borland makefiles. MSYS Makefiles = Generates MSYS makefiles. MinGW Makefiles = Generates a make file for use with mingw32-make. NMake Makefiles = Generates NMake makefiles. Unix Makefiles = Generates standard UNIX makefiles. Visual Studio 6 = Generates Visual Studio 6 project files. Visual Studio 7 = Generates Visual Studio .NET 2002 project files. Visual Studio 7 .NET 2003 = Generates Visual Studio .NET 2003 project files. Visual Studio 8 2005 = Generates Visual Studio .NET 2005 project files. Visual Studio 8 2005 Win64 = Generates Visual Studio .NET 2005 Win64 project files. Visual Studio 9 2008 = Generates Visual Studio 9 2008 project fil Visual Studio 9 2008 Win64 = Generates Visual Studio 9 2008 Win64 proje files. [...] It is likely that your `CMake' binary will support more compilers, known by `CMake' as _generators_, than supported by MySQL Connector/C++. We have built the connector using the following generators: * Microsoft Visual Studio 8 (Visual Studio 2005) * Microsoft Visual Studio 9 (Visual Studio 2008, Visual Studio 2008 Express) * NMake Please see the building instructions for Unix, Solaris and Mac OS X for troubleshooting and configuration hints. The steps to build the connector are given below: 1. Run `CMake' to generate build files for your _generator_: *Visual Studio* C:\path_to_mysql_cpp>cmake -G "Visual Studio 9 2008" -- Check for working C compiler: cl -- Check for working C compiler: cl -- works -- Detecting C compiler ABI info -- Detecting C compiler ABI info - done -- Check for working CXX compiler: cl -- Check for working CXX compiler: cl -- works -- Detecting CXX compiler ABI info -- Detecting CXX compiler ABI info - done -- ENV{MYSQL_DIR} = -- MySQL Include dir: C:/Programme/MySQL/MySQL Server 5.1/include -- MySQL Library : C:/Progams/MySQL/MySQL Server 5.1/lib/opt/mysqlclient.lib -- MySQL Library dir: C:/Progams/MySQL/MySQL Server 5.1/lib/opt -- MySQL CFLAGS: -- MySQL Link flags: -- MySQL Include dir: C:/Progams/MySQL/MySQL Server 5.1/include -- MySQL Library dir: C:/Progams/MySQL/MySQL Server 5.1/lib/opt -- MySQL CFLAGS: -- MySQL Link flags: -- Configuring cppconn -- Configuring test cases -- Looking for isinf -- Looking for isinf - not found -- Looking for isinf -- Looking for isinf - not found. -- Looking for finite -- Looking for finite - not found. -- Configuring C/J junit tests port -- Configuring examples -- Configuring done -- Generating done -- Build files have been written to: C:\path_to_mysql_cpp C:\path_to_mysql_cpp>dir *.sln *.vcproj [...] 19.11.2008 12:16 23.332 MYSQLCPPCONN.sln [...] 19.11.2008 12:16 27.564 ALL_BUILD.vcproj 19.11.2008 12:16 27.869 INSTALL.vcproj 19.11.2008 12:16 28.073 PACKAGE.vcproj 19.11.2008 12:16 27.495 ZERO_CHECK.vcproj *NMake* C:\path_to_mysql_cpp>cmake -G "NMake Makefiles" -- The C compiler identification is MSVC -- The CXX compiler identification is MSVC [...] -- Build files have been written to: C:\path_to_mysql_cpp 2. Use your compiler to build MySQL Connector/C++ *Visual Studio - GUI* Open the newly generated project files in the Visual Studio GUI or use a Visual Studio command line to build the driver. The project files contain a variety of different configurations. Among them debug and nondebug versions. *Visual Studio - NMake* C:\path_to_mysql_cpp>nmake Microsoft (R) Program Maintenance Utility Version 9.00.30729.01 Copyright (C) Microsoft Corporation. All rights reserved. Scanning dependencies of target mysqlcppconn [ 2%] Building CXX object driver/CMakeFiles/mysqlcppconn.dir/mysql_connection.obj mysql_connection.cpp [...] Linking CXX executable statement.exe [100%] Built target statement  File: manual.info, Node: connector-cpp-dynamic-linking-client-library, Prev: connector-cpp-installation-source-windows, Up: connector-cpp-installation-source 21.5.2.3 Dynamically Linking MySQL Connector/C++ against the MySQL Client Library ................................................................................. *Note*: Note this section refers to dynamic linking of the MySQL Connector/C++ with the client library, not the dynamic linking of the application to MySQL Connector/C++. An application that uses MySQL Connector/C++ can be either statically or dynamically linked to the MySQL Connector/C++ libraries. MySQL Connector/C++ is usually statically linked to the underlying MySQL Client Library (or Connector/C). Note, that unless otherwise stated, reference to the MySQL Client Library is also taken to include Connector/C, which is a separately packaged, stand alone version of the MySQL Client Library. From MySQL Connector/C++ version 1.1.0 it is possible to also dynamically link to the underlying MySQL Client Library. The ability of MySQL Connector/C++ to dynamically link to MySQL Client Library is not enabled by default, and enabling this feature is done through a compile time option, when compiling the MySQL Connector/C++ source code. To use the ability to dynamically link the client library to MySQL Connector/C++ the `MYSQLCLIENT_STATIC_BINDING:BOOL' needs to be defined when building the MySQL Connector/C++ source code: rm CMakeCache.txt cmake -DMYSQLCLIENT_STATIC_BINDING:BOOL=1 . make clean make make install Note that precompiled binaries of MySQL Connector/C++ use static binding with the client library by default. Now, in your application, when creating a connection, MySQL Connector/C++ will select and load a client library at runtime. It will choose the client library by searching defined locations and environment variables depending on the host operating system. It also possible when creating a connection in an application to define an absolute path to the client library to be loaded at runtime. This can be convenient if you have defined a standard location from which you want the client library to be loaded. This is sometimes done to circumvent possible conflicts with other versions of the client library that may be located on the system.  File: manual.info, Node: connector-cpp-apps-windows-visual-studio, Next: connector-cpp-apps-linux-netbeans, Prev: connector-cpp-installation-source, Up: connector-cpp 21.5.3 MySQL Connector/C++ Building Windows applications with Microsoft Visual Studio ------------------------------------------------------------------------------------- MySQL Connector/C++ is available as a static or dynamic library to use with your application. This section looks at how to link the library to your application. *Note*: To avoid potential crashes the build configuration of MySQL Connector/C++ should match the build configuration of the application using it. For example, do not use the release build of MySQL Connector/C++ with a debug build of the client application. *Static library* The MySQL Connector/C++ static library file is `mysqlcppconn-static.lib'. This needs to be statically linked with your application. You also need to link against the files `libmysql.dll' and `libmysql.lib'. Once linking has been successfully completed, the application will require access to `libmysql.dll' at run time. *Dynamic library* The MySQL Connector/C++ dynamic library file is `mysqlcppconn.dll'. To build your client application, you must link it with the file `mysqlcppconn.lib'. At run time, the application will require access to the files `mysqlcppconn.dll' and `libmysql.dll'. *Building a MySQL Connector/C++ application with Microsoft Visual Studio* Initially, the procedure for building an application to use either the static or dynamic library is the same. You then carry out some additional steps depending on whether you want to build your application to use the static or dynamic library. 1. Select `File', `New', `Project' from the main menu. FIGURE GOES HERE: Creating a New Project 2. In the wizard select `Visual C++', `Win32'. From `Visual Studio Installed Templates' select the application type `Win32 Console Application'. Enter a name for the application, and then click `OK', to move to the Win32 Application Wizard. FIGURE GOES HERE: The New Project Dialog Box 3. In the Win32 Application Wizard, click `Application Settings' and ensure the defaults are selected. The radio button `Console application', and the check box `Precompiled headers' will be selected. Click `Finish' to close the wizard. FIGURE GOES HERE: The Win32 Application Wizard 4. From the drop down list box on the toolbar, change from the default `Debug' build to the `Release' build. FIGURE GOES HERE: Selecting the Release Build 5. From the main menu select `Project', `Properties'. This can also be accessed using the hot key `ALT' + `F7'. FIGURE GOES HERE: Selecting Project Properties from the Main Menu 6. Under `Configuration Properties', open the tree view. 7. Select `C++', `General' in the tree view. FIGURE GOES HERE: Setting Properties 8. You now need to ensure that Visual Studio can find the MySQL include directory. This directory includes header files that can optionally be installed when installing MySQL Server. FIGURE GOES HERE: MySQL Include Directory 9. Then in the `Additional Include Directories' text field, add the MySQL `include/' directory. FIGURE GOES HERE: Select Directory Dialog 10. You will also need to set the location of additional libraries that Visual Studio will need to build the application. These are located in the MySQL `lib/opt' directory, a sub-directory of the MySQL Server installation directory. FIGURE GOES HERE: Typical Contents of MySQL lib/opt Directory 11. In the tree view open `Linker', `General', `Additional Library Directories'. FIGURE GOES HERE: Additional Library Directories 12. Add the `lib/opt' directory into the `Additional Library Directories' text field. This enables the library file `libmysql.lib' to be found. FIGURE GOES HERE: Additional Library Directories Dialog The remaining steps depend on whether you are building an application to use the MySQL Connector/C++ static or dynamic library. If you are building your application to use the dynamic library go here. If you are building your application to use the static library, carry out the following steps: 1. Then open `Linker', `Input', `Additional Dependencies'. FIGURE GOES HERE: 2. Enter `mysqlcppconn-static.lib' and `libmysql.lib'. FIGURE GOES HERE: Adding Additional Dependencies 3. By default `CPPCONN_PUBLIC_FUNC' is defined to declare functions to be compatible with an application that calls a DLL. If building an application to call the static library, you must ensure that function prototypes are compatible with this. In this case `CPPCONN_PUBLIC_FUNC' needs to be defined to be an empty string, so that functions are declared with the correct prototype. In the `Project', `Properties' tree view, under `C++', `Preprocessor', enter `CPPCONN_PUBLIC_FUNC=' into the `Preprocessor Definitions' text field. FIGURE GOES HERE: Setting the CPPCONN_PUBLIC_FUNC Define *Note*: Make sure you enter `CPPCONN_PUBLIC_FUNC=' and not `CPPCONN_PUBLIC_FUNC', as it needs to be defined as an empty string. If building an application to use the MySQL Connector/C++ dynamically linked library carry out these steps: 1. Under `Linker', `Input', add `mysqlcppconn.lib' into the `Additional Dependencies' text field. 2. The application will need to access the MySQL Connector/C++ Dynamic Linked Library at run time. Therefore, `mysqlcppconn.dll' needs to be in the same directory as the application executable, or somewhere on the system's path. Copy `mysqlcppconn.dll' to the same directory as the application. Alternatively, extend the `PATH' environment variable using `SET PATH=%PATH%;C:\path\to\cpp'. Alternatively, you can copy `mysqlcppconn.dll' to the Windows installation Directory, typically `c:\windows'.  File: manual.info, Node: connector-cpp-apps-linux-netbeans, Next: connector-cpp-getting-started-examples, Prev: connector-cpp-apps-windows-visual-studio, Up: connector-cpp 21.5.4 MySQL Connector/C++ Building Linux applications with NetBeans -------------------------------------------------------------------- This section describes how you can build MySQL Connector/C++ applications for Linux using the NetBeans IDE. FIGURE GOES HERE: The NetBeans IDE *Note*: To avoid potential crashes the build configuration of MySQL Connector/C++ should match the build configuration of the application using it. For example, do not use the release build of MySQL Connector/C++ with a debug build of the client application. 1. The first step of building your application is to create a new project. Select `File', `New Project'. Choose a `C/C++ Application' and click `Next'. 2. Give the project a name and click `Finish'. A new project is created. 3. In the `Projects' tab, right-click `Source Files' and select `New', then `Main C++ File...'. 4. Change the filename, or simply select the defaults and click `Finish' to add the new file to the project. 5. You now need to add some working code to you main source file. Explore your MySQL Connector/C++ installation and navigate to the `examples' directory. 6. Select a suitable example such as `standalone_example_docs1.cpp'. Copy all the code in this file, and use it to replace the code in your existing main source file. Amend the code to reflect the connection properties required for your test database. You now have a working example that will access a MySQL database using MySQL Connector/C++. 7. You will notice that at this point NetBeans is showing some errors in the source code. This is because you need to direct NetBeans to the necessary header files that need to be included. Select `File', `Project Properties' from the main menu. 8. In the `Categories:' tree view panel, navigate to `Build', `C++ Compiler'. 9. In the `General' panel, select `Include Directories'. 10. Click the `...' button. 11. Click `Add' and then navigate to the directory where the MySQL Connector/C++ header files are located. This will be `/usr/local/include' unless you have installed the files to a different location. Click `Select'. Click `OK'. FIGURE GOES HERE: Setting the Header Include Directory 12. Click `OK' again to close the `Project Properties' dialog. At this point you have created a NetBeans project, containing a single C++ source file. You have also ensured that the necessary include files are accessible. Before continuing, you need to decide whether your project is to use the MySQL Connector/C++ static or dynamic library. The project settings are slightly different in each case, as you need to link against a different library. *Using the static library* If you intend to use the static library you will need to link against two library files, `libmysqlcppconn-static.a' and `libmysqlclient.a'. The locations of the files will depend on your setup, but typically the former will be found in `/usr/local/lib' and the latter in `/usr/lib'. Note the file `libmysqlclient.a' is not part of MySQL Connector/C++, but is the MySQL Client Library file distributed with MySQL Server. Remember, the MySQL Client Library is an optional component as part of the MySQL Server installation process. Note the MySQL Client Library is also available as part of the new MySQL Connector/C distribution. 1. The first step is to set the project to link the necessary library files. Select `File', `Project Properties' from the main menu. 2. In the `Categories:' tree view navigate to `Linker'. 3. In the `General' panel select `Additional Library Directories'. Click the `...' button. 4. Select and add the `/usr/lib' and `/usr/local/lib' directories. 5. In the same panel add the two library files required for static linking as discussed earlier. The properties panel should then look similar to the following screenshot: FIGURE GOES HERE: Setting the Static Library Directories and File Names 6. Click `OK' to close the `Project Properties' dialog. *Using the dynamic library* If you require your application to use the MySQL Connector/C++ dynamic library, you simply need to link your project with a single library file, `libmysqlcppconn.so'. The location of this file will depend on how you configured your installation of MySQL Connector/C++, but will typically be `/usr/local/lib'. 1. The first step is to set the project to link the necessary library file. Select `File', `Project Properties' from the main menu. 2. In the `Categories:' tree view navigate to `Linker'. 3. In the `General' panel select `Additional Library Directories'. Click the `...' button. 4. Select and add the `/usr/local/lib' directories. 5. In the same panel add the library file required for static linking as discussed earlier. The properties panel should then look similar to the following screenshot: FIGURE GOES HERE: Setting the Dynamic Library Directory and File Name 6. Click OK to close the Project Properties dialog. Having configured your project you can build it by selecting `Run', `Build Main Project' from the main menu. You can then run the project using `Run', `Run Main Project'. On running the application you should see a screen similar to the following (this is actually the static version of the application shown): FIGURE GOES HERE: The Example Application Running *Note*: Note the above settings and procedures were carried out for the default `Debug' configuration. If you want to create a `Release' configuration you will need to select that configuration before setting the Project Properties.  File: manual.info, Node: connector-cpp-getting-started-examples, Next: connector-cpp-tutorials, Prev: connector-cpp-apps-linux-netbeans, Up: connector-cpp 21.5.5 MySQL Connector/C++ Getting Started: Usage Examples ---------------------------------------------------------- * Menu: * connector-cpp-examples-connecting:: MySQL Connector/C++ Connecting to MySQL * connector-cpp-examples-query:: MySQL Connector/C++ Running a simple query * connector-cpp-examples-results:: MySQL Connector/C++ Fetching results * connector-cpp-examples-prepared-statements:: MySQL Connector/C++ Using Prepared Statements * connector-cpp-examples-complete-example-1:: MySQL Connector/C++ Complete Example 1 * connector-cpp-examples-complete-example-2:: MySQL Connector/C++ Complete Example 2 The download package contains usage examples in the directory `examples/'. The examples explain the basic usage of the following classes: * Connection * Driver * PreparedStatement * ResultSet * ResultSetMetaData * Statement The examples cover: * Using the Driver class to connect to MySQL * Creating tables, inserting rows, fetching rows using (simple) statements * Creating tables, inserting rows, fetching rows using prepared statements * Hints for working around prepared statement limitations * Accessing result set metadata The examples in this document are only code snippets. The code snippets provide a brief overview on the API. They are not complete programs. Please check the `examples/' directory of your MySQL Connector/C++ installation for complete programs. Please also read the `README' file in the `examples/' directory. Note to test the example code you will first need to edit the `examples.h' file in the `examples/' directory, to add your connection information. Then simply rebuild the code by issuing a `make' command. The examples in the `examples/' directory include: * `examples/connect.cpp': How to create a connection, insert data into MySQL and handle exceptions. * `examples/connection_meta_schemaobj.cpp': How to obtain metadata associated with a connection object, for example, a list of tables, databases, MySQL version, connector version. * `examples/debug_output.cpp': How to activate and deactivate the MySQL Connector/C++ debug protocol. * `examples/exceptions.cpp': A closer look at the exceptions thrown by the connector and how to fetch error information. * `examples/prepared_statements.cpp': How to run Prepared Statements including an example how to handle SQL commands that cannot be prepared by the MySQL Server. * `examples/resultset.cpp': How to fetch data and iterate over the result set (cursor). * `examples/resultset_meta.cpp': How to obtain metadata associated with a result set, for example, number of columns and column types. * `examples/resultset_types.cpp': Result sets returned from metadata methods - this is more a test than much of an example. * `examples/standalone_example.cpp': Simple standalone program not integrated into regular `CMake' builds. * `examples/statements.cpp': How to run SQL commands without using Prepared Statements. * `examples/cpp_trace_analyzer.cpp': This example shows how to filter the output of the *Note debug trace: connector-cpp-debug-tracing. Please see the inline comments for further documentation. This script is unsupported.  File: manual.info, Node: connector-cpp-examples-connecting, Next: connector-cpp-examples-query, Prev: connector-cpp-getting-started-examples, Up: connector-cpp-getting-started-examples 21.5.5.1 MySQL Connector/C++ Connecting to MySQL ................................................ A connection to MySQL is established by retrieving an instance of sql::Connection from a sql::mysql::MySQL_Driver object. A sql::mysql::MySQL_Driver object is returned by sql::mysql::MySQL_Driver::get_mysql_driver_instance(). sql::mysql::MySQL_Driver *driver; sql::Connection *con; driver = sql::mysql::MySQL_Driver::get_mysql_driver_instance(); con = driver->connect("tcp://127.0.0.1:3306", "user", "password"); delete con; Make sure that you free the sql::Connection object as soon as you do not need it any more. But do not explicitly free the connector object!  File: manual.info, Node: connector-cpp-examples-query, Next: connector-cpp-examples-results, Prev: connector-cpp-examples-connecting, Up: connector-cpp-getting-started-examples 21.5.5.2 MySQL Connector/C++ Running a simple query ................................................... For running simple queries you can use the methods sql::Statement::execute(), sql::Statement::executeQuery() and sql::Statement::executeUpdate(). The method sql::Statement::execute() should be used if your query does not return a result set or if your query returns more than one result set. See the `examples/' directory for more on this. sql::mysql::MySQL_Driver *driver; sql::Connection *con; sql::Statement *stmt driver = sql::mysql::get_mysql_driver_instance(); con = driver->connect("tcp://127.0.0.1:3306", "user", "password"); stmt = con->createStatement(); stmt->execute("USE " EXAMPLE_DB); stmt->execute("DROP TABLE IF EXISTS test"); stmt->execute("CREATE TABLE test(id INT, label CHAR(1))"); stmt->execute("INSERT INTO test(id, label) VALUES (1, 'a')"); delete stmt; delete con; Note that you have to free sql::Statement and sql::Connection objects explicitly using delete.  File: manual.info, Node: connector-cpp-examples-results, Next: connector-cpp-examples-prepared-statements, Prev: connector-cpp-examples-query, Up: connector-cpp-getting-started-examples 21.5.5.3 MySQL Connector/C++ Fetching results ............................................. The API for fetching result sets is identical for (simple) statements and prepared statements. If your query returns one result set you should use sql::Statement::executeQuery() or sql::PreparedStatement::executeQuery() to run your query. Both methods return sql::ResultSet objects. The preview version does buffer all result sets on the client to support cursors. // ... sql::Connection *con; sql::Statement *stmt sql::ResultSet *res; // ... stmt = con->createStatement(); // ... res = stmt->executeQuery("SELECT id, label FROM test ORDER BY id ASC"); while (res->next()) { // You can use either numeric offsets... cout << "id = " << res->getInt(1); // getInt(1) returns the first column // ... or column names for accessing results. // The latter is recommended. cout << ", label = '" << res->getString("label") << "'" << endl; } delete res; delete stmt; delete con; *Note*: Note in the preceding code snippet that column indexing starts from 1. Note that you have to free sql::Statement, sql::Connection and sql::ResultSet objects explicitly using delete. The usage of cursors is demonstrated in the examples contained in the download package.  File: manual.info, Node: connector-cpp-examples-prepared-statements, Next: connector-cpp-examples-complete-example-1, Prev: connector-cpp-examples-results, Up: connector-cpp-getting-started-examples 21.5.5.4 MySQL Connector/C++ Using Prepared Statements ...................................................... If you are not familiar with Prepared Statements on MySQL have an extra look at the source code comments and explanations in the file `examples/prepared_statement.cpp'. sql::PreparedStatement is created by passing an SQL query to sql::Connection::prepareStatement(). As sql::PreparedStatement is derived from sql::Statement, you will feel familiar with the API once you have learned how to use (simple) statements (sql::Statement). For example, the syntax for fetching results is identical. // ... sql::Connection *con; sql::PreparedStatement *prep_stmt // ... prep_stmt = con->prepareStatement("INSERT INTO test(id, label) VALUES (?, ?)"); prep_stmt->setInt(1, 1); prep_stmt->setString(2, "a"); prep_stmt->execute(); prep_stmt->setInt(1, 2); prep_stmt->setString(2, "b"); prep_stmt->execute(); delete prep_stmt; delete con; As usual, you have to free sql::PreparedStatement and sql::Connection objects explicitly.  File: manual.info, Node: connector-cpp-examples-complete-example-1, Next: connector-cpp-examples-complete-example-2, Prev: connector-cpp-examples-prepared-statements, Up: connector-cpp-getting-started-examples 21.5.5.5 MySQL Connector/C++ Complete Example 1 ............................................... The following code shows a complete example of how to use MySQL Connector/C++: /* Copyright 2008, 2010, Oracle and/or its affiliates. All rights reserved. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; version 2 of the License. There are special exceptions to the terms and conditions of the GPL as it is applied to this software. View the full text of the exception in file EXCEPTIONS-CONNECTOR-C++ in the directory of this software distribution. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ /* Standard C++ includes */ #include #include /* Include directly the different headers from cppconn/ and mysql_driver.h + mysql_util.h (and mysql_connection.h). This will reduce your build time! */ #include "mysql_connection.h" #include #include #include #include using namespace std; int main(void) { cout << endl; cout << "Running 'SELECT 'Hello World!' » AS _message'..." << endl; try { sql::Driver *driver; sql::Connection *con; sql::Statement *stmt; sql::ResultSet *res; /* Create a connection */ driver = get_driver_instance(); con = driver->connect("tcp://127.0.0.1:3306", "root", "root"); /* Connect to the MySQL test database */ con->setSchema("test"); stmt = con->createStatement(); res = stmt->executeQuery("SELECT 'Hello World!' AS _message"); while (res->next()) { cout << "\t... MySQL replies: "; /* Access column data by alias or column name */ cout << res->getString("_message") << endl; cout << "\t... MySQL says it again: "; /* Access column fata by numeric offset, 1 is the first column */ cout << res->getString(1) << endl; } delete res; delete stmt; delete con; } catch (sql::SQLException &e) { cout << "# ERR: SQLException in " << __FILE__; cout << "(" << __FUNCTION__ << ") on line " » << __LINE__ << endl; cout << "# ERR: " << e.what(); cout << " (MySQL error code: " << e.getErrorCode(); cout << ", SQLState: " << e.getSQLState() << " )" << endl; } cout << endl; return EXIT_SUCCESS; }  File: manual.info, Node: connector-cpp-examples-complete-example-2, Prev: connector-cpp-examples-complete-example-1, Up: connector-cpp-getting-started-examples 21.5.5.6 MySQL Connector/C++ Complete Example 2 ............................................... The following code shows a complete example of how to use MySQL Connector/C++: /* Copyright 2008, 2010, Oracle and/or its affiliates. All rights reserved. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; version 2 of the License. There are special exceptions to the terms and conditions of the GPL as it is applied to this software. View the full text of the exception in file EXCEPTIONS-CONNECTOR-C++ in the directory of this software distribution. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ /* Standard C++ includes */ #include #include /* Include directly the different headers from cppconn/ and mysql_driver.h + mysql_util.h (and mysql_connection.h). This will reduce your build time! */ #include "mysql_connection.h" #include #include #include #include #include using namespace std; int main(void) { cout << endl; cout << "Let's have MySQL count from 10 to 1..." << endl; try { sql::Driver *driver; sql::Connection *con; sql::Statement *stmt; sql::ResultSet *res; sql::PreparedStatement *pstmt; /* Create a connection */ driver = get_driver_instance(); con = driver->connect("tcp://127.0.0.1:3306", "root", "root"); /* Connect to the MySQL test database */ con->setSchema("test"); stmt = con->createStatement(); stmt->execute("DROP TABLE IF EXISTS test"); stmt->execute("CREATE TABLE test(id INT)"); delete stmt; /* '?' is the supported placeholder syntax */ pstmt = con->prepareStatement("INSERT INTO test(id) VALUES (?)"); for (int i = 1; i <= 10; i++) { pstmt->setInt(1, i); pstmt->executeUpdate(); } delete pstmt; /* Select in ascending order */ pstmt = con->prepareStatement("SELECT id FROM test ORDER BY id ASC"); res = pstmt->executeQuery(); /* Fetch in reverse = descending order! */ res->afterLast(); while (res->previous()) cout << "\t... MySQL counts: " << res->getInt("id") << endl; delete res; delete pstmt; delete con; } catch (sql::SQLException &e) { cout << "# ERR: SQLException in " << __FILE__; cout << "(" << __FUNCTION__ << ") on line " » << __LINE__ << endl; cout << "# ERR: " << e.what(); cout << " (MySQL error code: " << e.getErrorCode(); cout << ", SQLState: " << e.getSQLState() << » " )" << endl; } cout << endl; return EXIT_SUCCESS; }  File: manual.info, Node: connector-cpp-tutorials, Next: connector-cpp-debug-tracing, Prev: connector-cpp-getting-started-examples, Up: connector-cpp 21.5.6 MySQL Connector/C++ Tutorials ------------------------------------ * Menu: * connector-cpp-tutorials-stored-routines-statements:: Tutorial: Calling Stored Procedures with Statements in MySQL Connector/C++ * connector-cpp-tutorials-stored-routines-prepared-statements:: Tutorial: Calling Stored Procedures with Prepared Statements in MySQL Connector/C++ Here are some tutorials on using MySQL Connector/C++. You should also have a look at the examples which can be found in the following section *Note connector-cpp-getting-started-examples::. *Setting up the World database for use in the tutorials* These tutorials primarily use the `World' database, so you need to have that installed. You can download the `World' database, and documentation on how to install it, from the MySQL Documentation (http://dev.mysql.com/doc/index-other.html) page - look for the section called `Example Databases'. *Tutorial framework code* Rather than repeating the same code, a framework is given here. You can reuse this framework with all the tutorials unless otherwise stated. This boiler plate code can then simply be reused for each tutorial. The framework code is given here: #include #include #include #include #include "mysql_connection.h" #include #include #include #include #include #define EXAMPLE_HOST "localhost" #define EXAMPLE_USER "root" #define EXAMPLE_PASS "" #define EXAMPLE_DB "world" using namespace std; int main(int argc, const char **argv) { string url(argc >= 2 ? argv[1] : EXAMPLE_HOST); const string user(argc >= 3 ? argv[2] : EXAMPLE_USER); const string pass(argc >= 4 ? argv[3] : EXAMPLE_PASS); const string database(argc >= 5 ? argv[4] : EXAMPLE_DB); cout << "Connector/C++ tutorial framework..." << endl; cout << endl; try { /* INSERT TUTORIAL CODE HERE! */ } catch (sql::SQLException &e) { /* The MySQL Connector/C++ throws three different exceptions: - sql::MethodNotImplementedException (derived from sql::SQLException) - sql::InvalidArgumentException (derived from sql::SQLException) - sql::SQLException (derived from std::runtime_error) */ cout << "# ERR: SQLException in " << __FILE__; cout << "(" << __FUNCTION__ << ") on line " << __LINE__ << endl; /* Use what() (derived from std::runtime_error) to fetch the error message */ cout << "# ERR: " << e.what(); cout << " (MySQL error code: " << e.getErrorCode(); cout << ", SQLState: " << e.getSQLState() << " )" << endl; return EXIT_FAILURE; } cout << "Done." << endl; return EXIT_SUCCESS; } *To compile and run the framework* First, copy and paste the framework code to a file such as `frmwk.cpp'. Edit the `#define' statements to reflect your connection details (server, user, password, database). To compile the framework, for example on Mac OS X, type: shell> g++ -o frmwk -I/usr/local/include -I/usr/local/include/cppconn -lmysqlcppconn frmwk.cpp To run the framework, enter the following: shell> ./frmwk You will see a simple message. You are now ready to continue to the tutorials.  File: manual.info, Node: connector-cpp-tutorials-stored-routines-statements, Next: connector-cpp-tutorials-stored-routines-prepared-statements, Prev: connector-cpp-tutorials, Up: connector-cpp-tutorials 21.5.6.1 Tutorial: Calling Stored Procedures with Statements in MySQL Connector/C++ ................................................................................... Stored Procedures can be called using both Statements and Prepared Statements. This tutorial looks at calling Stored Procedures using Statements. The following tutorial *Note connector-cpp-tutorials-stored-routines-prepared-statements:: will cover the use of Prepared Statements. When considering calling Stored Procedures there are several scenarios that can occur: 1. A Stored Procedure that does not return a result set. 2. A Stored Procedure that returns an output parameter. 3. A Stored Procedure that returns a result set. Stored Procedures are given below that illustrate each of the above scenarios. The following routine enables you to add a country into the World database, but does not return a result. This corresponds to Scenario 1 above. CREATE PROCEDURE add_country (IN country_code CHAR(3), IN country_name CHAR(52), IN continent_name CHAR(30)) BEGIN INSERT INTO Country(Code, Name, Continent) VALUES (country_code, country_name, continent_name); END The next routine returns the population of a specified country, and corresponds to Scenario 2 above: CREATE PROCEDURE get_pop (IN country_name CHAR(52), OUT country_pop INT(11)) BEGIN SELECT Population INTO country_pop FROM Country WHERE Name = country_name; END The next routine is an example of a procedure returning a result set containing multiple records. This routine corresponds to Scenario 3 above. CREATE PROCEDURE get_data () BEGIN SELECT Code, Name, Population, Continent FROM Country WHERE Continent = "Oceania" AND Population < 10000; SELECT Code, Name, Population, Continent FROM Country WHERE Continent = "Europe" AND Population < 10000; SELECT Code, Name, Population, Continent FROM Country WHERE Continent = "North America" AND Population < 10000; END Enter and test the Stored Procedures to ensure no errors have been introduced. You are now ready to start writing routines to test out the use of Stored Procedures using Connector/C++. *Scenario 1 - Stored Procedure does not return a result set* In the first case you will examine Scenario 1, you call a Stored procedure that does not return a result set. 1. Make a copy of the tutorial framework code. 2. Insert the following code into the framework at the correct location (denoted by an INSERT HERE comment in the framework). sql::Driver* driver = get_driver_instance(); std::auto_ptr con(driver->connect(url, user, pass)); con->setSchema(database); std::auto_ptr stmt(con->createStatement()); // We don't need to check the return value explicitly, if it indicates // an error Connector/C++ will generate an exception. stmt->execute("CALL add_country(\"ATL\", \"Atlantis\", \"North America\")"); 3. Compile the program using the following command: shell> g++ -o sp_scenario1 -I/usr/local/include/cppconn/ -lmysqlcppconn sp_scenario1.cpp 4. Run the program by typing: shell> ./sp_scenario1 5. Using the MySQL Command Line Client, or other suitable tool, check the World database to determine that it has been updated correctly. You can use a query such as: SELECT Code, Name, Continent FROM Country WHERE Code="ATL"; The code in this case simply creates a statement and then invokes the execute method on it, passing the call to the Stored Procedure as a parameter. The Stored Procedure itself does not return a value, although it is important to note there will always be a return value from the call - this is simply the call status. MySQL Connector/C++ handles this status for you, so you do not need code to handle it explicitly. If the call should fail for some reason an exception will be raised, and this will be handled by the `catch' statement in the code. *Scenario 2 - Stored Procedure returns an output parameter* You will now see how to handle a Stored Procedure that returns an output parameter. 1. Enter the following code into the tutorial framework code: sql::Driver* driver = get_driver_instance(); std::auto_ptr con(driver->connect(url, user, pass)); con->setSchema(database); std::auto_ptr stmt(con->createStatement()); stmt->execute("CALL get_pop(\"Uganda\", @pop)"); std::auto_ptr res(stmt->executeQuery("SELECT @pop AS _reply")); while (res->next()) cout << "Population of Uganda: " << res->getString("_reply") << endl; stmt->execute("CALL get_pop_continent(\"Asia\", @pop)"); res.reset(stmt->executeQuery("SELECT @pop AS _reply")); while (res->next()) cout << "Population of Asia: " << res->getString("_reply") << endl; stmt->execute("CALL get_world_pop(@pop)"); res.reset(stmt->executeQuery("SELECT @pop AS _reply")); while (res->next()) cout << "Population of World: " << res->getString("_reply") << endl; 2. Compile the program using the following command: shell> g++ -o sp_scenario2 -I/usr/local/include/cppconn/ -lmysqlcppconn sp_scenario2.cpp 3. Run the program by typing: shell> ./sp_scenario2 Note the output generated by the program. In this scenario the Stored Procedure sets an output parameter. This is not returned as such, but needs to be obtained using a query. If running the SQL statements directly this might be similar to the following: CALL get_world_pop(@pop); SELECT @pop; In the C++ code a similar sequence is carried out. First, the `CALL' is executed as seen earlier. To obtain the output parameter an additional query must be executed. This query results in a `ResultSet' that can then be processed in a `while' loop. The simplest way to retrieve the data in this case is to use a getString method on the ResultSet, passing the name of the variable to access. In this example `_reply' is used as a placeholder for the variable and therefore is used as the key to access the correct element of the result dictionary. *Scenario 3 - Stored Procedure returns a Result Set* You will now see how to handle a Stored Procedure that returns a result set. 1. Enter the following code into the tutorial framework code: sql::Driver* driver = get_driver_instance(); std::auto_ptr con(driver->connect(url, user, pass)); con->setSchema(database); std::auto_ptr stmt(con->createStatement()); stmt->execute("CALL get_stats()"); std::auto_ptr< sql::ResultSet > res; do { res.reset(stmt->getResultSet()); while (res->next()) { cout << "Result: " << res->getString(1) << endl; } } while (stmt->getMoreResults()); 2. Compile the program using the following command: shell> g++ -o sp_scenario3 -I/usr/local/include/cppconn/ -lmysqlcppconn sp_scenario3.cpp 3. Run the program by typing: shell> ./sp_scenario3 Note the output generated by the program. The code is similar to the examples you have previously seen. The code of particular interest in this case is: do { res.reset(stmt->getResultSet()); while (res->next()) { cout << "Name: " << res->getString("Name") << " Population: " << res->getInt("Population") << endl; } } while (stmt->getMoreResults()); The `CALL' is executed as before, with the results being returned into multiple `ResultSet's. This is because the Stored Procedure in this case uses multiple `SELECT' statements. In this example the output shows that three Result Sets are processed, because there are three `SELECT' statements in the Stored Procedure. All of the Result Sets have more than one row. Studying the code it should be noted that the results are processed using the pattern: do { Get Result Set while (Get Result) { Process Result } } while (Get More Result Sets); *Note*: Note this pattern would be used even if the Stored Procedure carried out a single `SELECT' and you knew there was only one result set. This is a requirement of the underlying protocol.  File: manual.info, Node: connector-cpp-tutorials-stored-routines-prepared-statements, Prev: connector-cpp-tutorials-stored-routines-statements, Up: connector-cpp-tutorials 21.5.6.2 Tutorial: Calling Stored Procedures with Prepared Statements in MySQL Connector/C++ ............................................................................................ Before working through this tutorial it is recommended you first work through the previous tutorial *Note connector-cpp-tutorials-stored-routines-statements::. *Scenario 1 - Using a Prepared Statement to prepare a Stored Procedure that does not return a result set* 1. Add the following code to the `try' block of the tutorial framework: vector code_vector; code_vector.push_back("SLD"); code_vector.push_back("DSN"); code_vector.push_back("ATL"); vector name_vector; name_vector.push_back("Sealand"); name_vector.push_back("Disneyland"); name_vector.push_back("Atlantis"); vector cont_vector; cont_vector.push_back("Europe"); cont_vector.push_back("North America"); cont_vector.push_back("Oceania"); sql::Driver * driver = get_driver_instance(); std::auto_ptr< sql::Connection > con(driver->connect(url, user, pass)); con->setSchema(database); std::auto_ptr< sql::PreparedStatement > pstmt; pstmt.reset(con->prepareStatement("CALL add_country(?,?,?)")); for (int i=0; i<3; i++) { pstmt->setString(1,code_vector[i]); pstmt->setString(2,name_vector[i]); pstmt->setString(3,cont_vector[i]); pstmt->execute(); } You will also need to add `#include ' to the top of your code as vectors are used to store sample data. 2. Compile the code using the following command: g++ -o ps_scenario1 -I/usr/local/include/cppconn/ -lmysqlcppconn ps_scenario1.cpp 3. Run the code using the command: ./ps_scenario1 4. You can test the database has been updated correctly by using a query such as: SELECT Code, Name, Continent FROM Country WHERE Code = "DSN" OR Code="ATL" OR Code="SLD"; The code is relatively simple, as no processing is required to handle Result Sets. The procedure call, `CALL add_country(?,?,?)', is made using placeholders for input parameters denoted by '?'. These placeholders are replaced by values using the Prepared Statement's `setString' method in this case. The `for' loop is set up to iterate 3 times, as there are three data sets in this example. The same Prepared Statement is executed three times, each time with different input parameters. *Scenario 2 - Using a Prepared Statement to prepare a Stored Procedure that uses an output parameter* In this scenario a different Stored Procedure is going to be used compared to the one used in the tutorial *Note connector-cpp-tutorials-stored-routines-statements::. This is to illustrate passing an input parameter as well as fetching an output parameter. The stored routine is as follows: CREATE PROCEDURE get_pop_continent (IN continent_name CHAR(30), OUT continent_pop INT(11)) BEGIN SELECT SUM(Population) INTO continent_pop FROM Country WHERE Continent = continent_name; END 1. Copy the following code into the try block of the tutorial framework code: vector cont_vector; cont_vector.push_back("Europe"); cont_vector.push_back("North America"); cont_vector.push_back("Oceania"); sql::Driver * driver = get_driver_instance(); std::auto_ptr< sql::Connection > con(driver->connect(url, user, pass)); con->setSchema(database); std::auto_ptr< sql::Statement > stmt(con->createStatement()); std::auto_ptr< sql::PreparedStatement > pstmt; std::auto_ptr< sql::ResultSet > res; pstmt.reset(con->prepareStatement("CALL get_pop_continent(?,@pop)")); for (int i=0; i<3; i++) { pstmt->setString(1,cont_vector[i]); pstmt->execute(); res.reset(stmt->executeQuery("SELECT @pop AS _population")); while (res->next()) cout << "Population of " << cont_vector[i] << " is " << res->getString("_population") << endl; } You will also need to add the line `#include ' to the top of the code, as vectors are used in this example. 2. Compile the code using: shell> g++ -o ps_scenario2 -I/usr/local/include/cppconn/ -lmysqlcppconn ps_scenario2.cpp 3. Run the code using: shell> ./ps_scenario2 4. Make a note of the output. In this scenario a Prepared Statement is created that calls the Stored Procedure `get_pop_continent'. This procedure takes an input parameter, and also returns an output parameter. The approach used is to create another statement that can be used to fetch the output parameter using a `SELECT' query. Note that when the Prepared Statement is created, the input parameter to the Stored Procedure is denoted by '?'. Prior to execution of Prepared Statement it is necessary to replace this placeholder by an actual value. This is done using methods such as `setString' and `setInt', for example: pstmt->setString(1,cont_vector[i]); Although for the query used to obtain the output parameter a single result set is expected, it is important to use the `while' loop to catch more than one result, to avoid the possibility of the connection becoming unstable. *Scenario 3 - Using a Prepared Statement to prepare a Stored Procedure that returns multiple Result Sets* *Note*: Note this scenario is not supported on versions of MySQL prior to 5.5.3. This is due to a limitation in the client/server protocol. 1. Enter the following code into the `try' block of the tutorial framework: sql::Driver * driver = get_driver_instance(); std::auto_ptr< sql::Connection > con(driver->connect(url, user, pass)); con->setSchema(database); std::auto_ptr< sql::PreparedStatement > pstmt; std::auto_ptr< sql::ResultSet > res; pstmt.reset(con->prepareStatement("CALL get_data()")); res.reset(pstmt->executeQuery()); do { res.reset(pstmt->getResultSet()); while (res->next()) { cout << "Name: " << res->getString("Name") << " Population: " << res->getInt("Population") << endl; } } while (pstmt->getMoreResults()); 2. Compile the code using the following command: shell> g++ -o ps_scenario3 -I/usr/local/include/cppconn/ -lmysqlcppconn ps_scenario3.cpp 3. Run the program using the command: shell> ./ps_scenario3 4. Make a note of the output generated. The code executes the Stored Procedure using a Prepared Statement. The standard do-while construct is used to ensure that all Result Sets are fetched. In this case the returned values are fetched from the Result Sets using the `getInt' and `getString' methods.  File: manual.info, Node: connector-cpp-debug-tracing, Next: connector-cpp-usage-notes, Prev: connector-cpp-tutorials, Up: connector-cpp 21.5.7 MySQL Connector/C++ Debug Tracing ---------------------------------------- Although a debugger can be used to debug your application, you may find it beneficial to turn on the debug traces of the connector. Some problems happen randomly which makes them difficult to debug using a debugger. In such cases debug traces and protocol files are more useful because they allow you to trace the activities of all instances of your program. DTrace is a very powerful technology to trace any application without having to develop an extra trace module for your application. Unfortunately, DTrace is currently only available on Solaris, MacOS 10.5, and FreeBSD. The MySQL Connector/C++ can write two trace files: 1. Trace file generated by the MySQL Client Library 2. Trace file generated internally by MySQL Connector/C++ The first trace file can be generated by the underlying MySQL Client Library (libmysql). To enable this trace the connector will call the C-API function `mysql_debug()' internally. Only debug versions of the MySQL Client Library are capable of writing a trace file. Therefore you need to compile MySQL Connector/C++ against a debug version of the library, if you want utilize this trace. The trace shows the internal function calls and the addresses of internal objects as you can see below: >mysql_stmt_init | >_mymalloc | | enter: Size: 816 | | exit: ptr: 0x68e7b8 | <_mymalloc | >init_alloc_root | | enter: root: 0x68e7b8 | | >_mymalloc | | | enter: Size: 2064 | | | exit: ptr: 0x68eb28 [...] The second trace is the MySQL Connector/C++ internal trace. It is available with debug and nondebug builds of the connector as long as you have enabled the tracing module at compile time using `cmake -DMYSQLCPPCONN_TRACE_ENABLE:BOOL=1'. By default, the tracing functionality is not available and calls to trace functions are removed by the preprocessor. Compiling the connector with tracing functionality enabled will cause two additional tracing function calls per each connector function call. You will need to run your own benchmark to find out how much this will impact the performance of your application. A simple test using a loop running 30,000 INSERT SQL statements showed no significant real-time impact. The two variants of this application using a trace enabled and trace disabled version of the connector performed equally well. The run time measured in real-time was not significantly impacted as long as writing a debug trace was not enabled. However, there will be a difference in the time spent in the application. When writing a debug trace the IO subsystem may become a bottleneck. In summary, use connector builds with tracing enabled carefully. Trace enabled versions may cause higher CPU usage even if the overall run time of your application is not impacted significantly. | INF: Tracing enabled MySQL_Prepared_Statement::setInt | INF: this=0x69a2e0 | >MySQL_Prepared_Statement::checkClosed | con(driver->connect(host, user, pass)); /* Activate debug trace of the MySQL Client Library (C-API) Only available with a debug build of the MySQL Client Library! */ con->setClientOption("libmysql_debug", "d:t:O,client.trace"); /* Tracing is available if you have compiled the driver using cmake -DMYSQLCPPCONN_TRACE_ENABLE:BOOL=1 */ con->setClientOption("client_trace", &on_off);  File: manual.info, Node: connector-cpp-usage-notes, Next: connector-cpp-bugs, Prev: connector-cpp-debug-tracing, Up: connector-cpp 21.5.8 MySQL Connector/C++ Usage Notes -------------------------------------- See the JDBC overview (http://java.sun.com/products/jdbc/overview.html) for information on JDBC 4.0. Please also check the `examples/' directory of the download package. *Notes on using the MySQL Connector/C++ API* * `DatabaseMetaData::supportsBatchUpdates()' returns `true' because MySQL supports batch updates in general. However, no API calls for batch updates are provided by the MySQL Connector/C++ API. * Two non-JDBC methods have been introduced for fetching and setting unsigned integers: `getUInt64()' and `getUInt()'. These are available for ResultSet and Prepared_Statement: * `ResultSet::getUInt64()' * `ResultSet::getUInt()' * `Prepared_Statement::setUInt64()' * `Prepared_Statement::setUInt()' The corresponding `getLong()' and `setLong()' methods have been removed. * The method `DatabaseMetaData::getColumns()' has 23 columns in its result set, rather than the 22 columns defined by JDBC. The first 22 columns are as described in the JDBC documentation, but column 23 is new: 23. `IS_AUTOINCREMENT': String which is `YES' if the column is an auto-increment column. Otherwise the string contains `NO'. * MySQL Connector/C++ may return different metadata for the same column. When you have any column that accepts a charset and a collation in its specification and you specify a binary collation, such as: CHAR(250) CHARACTER SET 'latin1' COLLATE 'latin1_bin' The server sets the `BINARY' flag in the result set metadata of this column. The method `ResultSetMetadata::getColumnTypeName()' uses the metadata and will report, due to the `BINARY' flag, that the column type name is `BINARY'. This is illustrated below: mysql> create table varbin(a varchar(20) character set utf8 collate utf8_bin); Query OK, 0 rows affected (0.00 sec) mysql> select * from varbin; Field 1: `a` Catalog: `def` Database: `test` Table: `varbin` Org_table: `varbin` Type: VAR_STRING Collation: latin1_swedish_ci (8) Length: 20 Max_length: 0 Decimals: 0 Flags: BINARY 0 rows in set (0.00 sec) mysql> select * from information_schema.columns where table_name='varbin'\G *************************** 1. row *************************** TABLE_CATALOG: NULL TABLE_SCHEMA: test TABLE_NAME: varbin COLUMN_NAME: a ORDINAL_POSITION: 1 COLUMN_DEFAULT: NULL IS_NULLABLE: YES DATA_TYPE: varchar CHARACTER_MAXIMUM_LENGTH: 20 CHARACTER_OCTET_LENGTH: 60 NUMERIC_PRECISION: NULL NUMERIC_SCALE: NULL CHARACTER_SET_NAME: utf8 COLLATION_NAME: utf8_bin COLUMN_TYPE: varchar(20) COLUMN_KEY: EXTRA: PRIVILEGES: select,insert,update,references COLUMN_COMMENT: 1 row in set (0.01 sec) However, `INFORMATION_SCHEMA' gives no hint in its `COLUMNS' table that metadata will contain the `BINARY' flag. `DatabaseMetaData::getColumns()' uses `INFORMATION_SCHEMA'. It will report the type name `CHAR' for the same column. Note, a different type code is also returned. * The MySQL Connector/C++ class sql::DataType defines the following JDBC standard data types: `UNKNOWN', `BIT', `TINYINT', `SMALLINT', `MEDIUMINT', `INTEGER', `BIGINT', `REAL', `DOUBLE', `DECIMAL', `NUMERIC', `CHAR', `BINARY', `VARCHAR', `VARBINARY', `LONGVARCHAR', `LONGVARBINARY', `TIMESTAMP', `DATE', `TIME', `GEOMETRY', `ENUM', `SET', `SQLNULL'. However, the following JDBC standard data types are _not_ supported by MySQL Connector/C++: `ARRAY', `BLOB', `CLOB', `DISTINCT', `FLOAT', `OTHER', `REF', `STRUCT'. * When inserting or updating `BLOB' or `TEXT' columns, MySQL Connector/C++ developers are advised not to use `setString()'. Instead it is recommended that the dedicated API function `setBlob()' be used instead. The use of `setString()' can cause a Packet too large (http://dev.mysql.com/doc/refman/5.1/en/packet-too-large.html) error message. The error will occur if the length of the string passed to the connector using `setString()' exceeds `max_allowed_packet' (minus a few bytes reserved in the protocol for control purposes). This situation is not handled in MySQL Connector/C++, as this could lead to security issues, such as extremely large memory allocation requests due to malevolently long strings. However, if `setBlob()' is used, this problem does not arise. This is because `setBlob()' takes a streaming approach based on `std::istream'. When sending the data from the stream to MySQL Server, MySQL Connector/C++ will split the stream into chunks appropriate for MySQL Server and observe the `max_allowed_packet' setting currently being used. *Caution*: When using `setString()' it is not possible to set `max_allowed_packet' to a value large enough for the string, prior to passing it to MySQL Connector/C++. The MySQL 5.1 documentation (http://dev.mysql.com/doc/refman/5.1/en/server-system-variables.html#sysvar_max_allowed_packet) for `max_allowed_packet' states: `As of MySQL 5.1.31, the session value of this variable is read only. Before 5.1.31, setting the session value is permitted but has no effect.' This difference with the JDBC specification ensures that MySQL Connector/C++ is not vulnerable to memory flooding attacks. * In general MySQL Connector/C++ works with MySQL 5.0, but it is not completely supported. Some methods may not be available when connecting to MySQL 5.0. This is because the Information Schema is used to obtain the requested information. There are no plans to improve the support for 5.0 because the current GA version of MySQL Server is 5.1. As a new product, MySQL Connector/C++ is primarily targeted at the MySQL Server GA version that was available on its release. The following methods will throw a `sql::MethodNotImplemented' exception when you connect to MySQL earlier than 5.1.0: * `DatabaseMetadata::getCrossReference()' * `DatabaseMetadata::getExportedKeys()' * MySQL Connector/C++ includes a method `Connection::getClientOption()' which is not included in the JDBC API specification. The prototype is: void getClientOption(const std::string & optionName, void * optionValue) The method can be used to check the value of connection properties set when establishing a database connection. The values are returned through the `optionValue' argument passed to the method with the type `void *'. Currently, `getClientOption()' supports fetching the `optionValue' of the following options: * `metadataUseInfoSchema' * `defaultStatementResultType' * `defaultPreparedStatementResultType' The connection option `metadataUseInfoSchema' controls whether to use the `Information_Schemata' for returning the meta data of `SHOW' commands. In the case of `metadataUseInfoSchema' the `optionValue' argument should be interpreted as a boolean upon return. In the case of both `defaultStatementResultType' and `defaultPreparedStatementResultType', the `optionValue' argument should be interpreted as an integer upon return. The connection property can be either set when establishing the connection through the connection property map or using `void Connection::setClientOption(const std::string & optionName, const void * optionValue)' where `optionName' is assigned the value `metadataUseInfoSchema'. Some examples are given below: int defaultStmtResType; int defaultPStmtResType; conn->getClientOption("defaultStatementResultType", (void *) &defaultStmtResType); conn->getClientOption("defaultPreparedStatementResultType", (void *) &defaultPStmtResType); bool isInfoSchemaUsed; conn->getClientOption("metadataUseInfoSchema", (void *) &isInfoSchemaUsed); * MySQL Connector/C++ also supports the following methods not found in the JDBC API standard: std::string MySQL_Connection::getSessionVariable(const std::string & varname) void MySQL_Connection::setSessionVariable(const std::string & varname, const std::string & value) Note that both methods are members of the `MySQL_Connection' class. The methods get and set MySQL session variables. `setSessionVariable()' is equivalent to executing: SET SESSION = `getSessionVariable()' is equivalent to executing the following and fetching the first return value: SHOW SESSION VARIABLES LIKE "" You can use `%' and other placeholders in , if the underlying MySQL server supports this. * Fetching the value of a column can sometimes return different values depending on whether the call is made from a Statement or Prepared Statement. This is because the protocol used to communicate with the server differs depending on whether a Statement or Prepared Statement is used. To illustrate this, consider the case where a column has been defined as of type `BIGINT'. The most negative `BIGINT' value is then inserted into the column. If a Statement and Prepared Statement are created that perform a `GetUInt64()' call, then the results will be found to be different in each case. The Statement returns the maximum positive value for `BIGINT'. The Prepared Statement returns 0. The reason for the different results is due to the fact that Statements use a text protocol, and Prepared Statements use a binary protocol. With the binary protocol in this case, a binary value is returned from the server that can be interpreted as an `int64'. In the above scenario a very large negative value was fetched with `GetUInt64()', which fetches unsigned integers. As the large negative value cannot be sensibly converted to an unsigned value 0 is returned. In the case of the Statement, which uses the text protocol, values are returned from the server as strings, and then converted as required. When a string value is returned from the server in the above scenario the large negative value will need to be converted by the runtime library function `strtoul()', which `GetUInt64()' calls. The behavior of `strtoul()' is dependent upon the specific runtime and host operating system, so the results can be variable. In the case given a large positive value was actually returned. Although it is very rare, there are some cases where Statements and Prepared Statements can return different values unexpectedly, but this usually only happens in extreme cases such as the one mentioned. * The JDBC documentation lists many fields (http://java.sun.com/j2se/1.4.2/docs/api/java/sql/DatabaseMetaData.html) for the `DatabaseMetaData' class. JDBC also appears to define certain values (http://java.sun.com/j2se/1.4.2/docs/api/constant-values.html#java.sql.DatabaseMetaData.attributeNoNulls) for those fields. However, MySQL Connector/C++ does not define certain values for those fields. Internally enumerations are used and the compiler determines the values to assign to a field. To compare a value with the field, code such as the following should be used, rather than making assumptions about specific values for the attribute: // dbmeta is an instance of DatabaseMetaData if (myvalue == dbmeta->attributeNoNulls) { ... } Usually MYVALUE will be a column from a result set holding metadata information. MySQL Connector/C++ does not guarantee that `attributeNoNulls' is 0. It can be any value. * When programming Stored Procedures JDBC has available an extra class, an extra abstraction layer for callable statements, the `CallableStatement' class. This is not present in MySQL Connector/C++. You therefore need to use the methods from the `Statement' and `Prepared Statement' classes to run a Stored Procedure using `CALL'.  File: manual.info, Node: connector-cpp-bugs, Next: connector-cpp-requests, Prev: connector-cpp-usage-notes, Up: connector-cpp 21.5.9 MySQL Connector/C++ Known Bugs and Issues ------------------------------------------------ *Note*: Please report bugs through MySQL Bug System (http://bugs.mysql.com). * Known bugs: * None. * Known issues: * * When linking against a static library for 1.0.3 on Windows you need to define `CPPDBC_PUBLIC_FUNC' either in the compiler options (preferable) or with `/D "CPPCONN_PUBLIC_FUNC="'. You can also explicitly define it in your code by placing `#define CPPCONN_PUBLIC_FUNC' before the header inclusions. * Generally speaking C++ library binaries are less portable than C library binaries. Issues can be caused by name mangling, different Standard Template Library (STL) versions and using different compilers and linkers for linking against the libraries than were used for building the library itself. Even a small change in the compiler version can, but does not have to, cause problems. If you obtain error messages, that you suspect are related to binary incompatibilities, build MySQL Connector/C++ from source, using the same compiler and linker that you will use to build and link your application. Due to the variations between Linux distributions, compiler and linker versions and STL versions, it is not possible to provide binaries for each and every possible configuration. However, the MySQL Connector/C++ binary distributions contain a `README' file that describes the environment and settings used to build the binary versions of the libraries. * To avoid potential crashes the build configuration of MySQL Connector/C++ should match the build configuration of the application using it. For example, do not use the release build of MySQL Connector/C++ with a debug build of the client application. See also the MySQL Connector/C++ Changelogs which can be found here *Note ccpp-news::.  File: manual.info, Node: connector-cpp-requests, Next: connector-cpp-support, Prev: connector-cpp-bugs, Up: connector-cpp 21.5.10 MySQL Connector/C++ Feature requests -------------------------------------------- You can suggest new features in the first instance by joining the mailing list or forum and talking with the developers directly. See *Note connector-cpp-support:: The following feature requests are currently being worked on: * C++ references for `Statements', `ResultSets', and exceptions, are being considered, instead of pointers to heap memory. This reduces the exception handling burden for the programmer. * Adopt STL (suggestions are welcome). * JDBC compliance: data type interfaces and support through `ResultSet:getType()' and `PreparedStatement:bind()'. Introduce `sql::Blob', `sql::Clob', `sql::Date', `sql::Time', `sql::Timestamp', `sql::URL'. Support `get|setBlob()', `get|setClob()', `get|setDate()', `get|setTime()', `get|setTimestamp()', `get|setURL()' * Add support for all C-API connection options. Improved support for `mysql_options'. * Add connect method which supports passing options using HashMaps. * Create Windows installer.  File: manual.info, Node: connector-cpp-support, Next: connector-cpp-faq, Prev: connector-cpp-requests, Up: connector-cpp 21.5.11 MySQL Connector/C++ Support ----------------------------------- For general discussion of the MySQL Connector/C++ please use the C/C++ community forum (http://forums.mysql.com/list.php?167) or join the MySQL Connector/C++ mailing list (http://lists.mysql.com). Bugs can be reported at the MySQL bug Web site (http://bugs.mysql.com). For Licensing questions, and to purchase MySQL Products and Services, please http://www.mysql.com/buy-mysql/ The MySQL Connector/C++ Changelogs can be found here *Note ccpp-news::  File: manual.info, Node: connector-cpp-faq, Prev: connector-cpp-support, Up: connector-cpp 21.5.12 MySQL Connector/C++ FAQ ------------------------------- *Questions* * 21.5.12.1: What is MySQL Connector/C++? * 21.5.12.2: Are any MySQL products using MySQL Connector/C++? * 21.5.12.3: Does MySQL Connector/C++ implement the client/server protocol? * 21.5.12.4: Which MySQL Server version(s) is MySQL Connector/C++ compatible with? *Questions and Answers* *21.5.12.1: ** What is MySQL Connector/C++? * MySQL Connector/C++ is a MySQL database connector for C++. It allows you develop applications in C++ that connect to the MySQL Server. MySQL Connector/C++ is compatible with the JDBC 4.0 API. *21.5.12.2: ** Are any MySQL products using MySQL Connector/C++? * Yes, MySQL Workbench and MySQL Connector/OpenOffice.org. *21.5.12.3: ** Does MySQL Connector/C++ implement the client/server protocol? * No. MySQL Connector/C++ uses the MySQL Client Library for the client/server communication. *21.5.12.4: ** Which MySQL Server version(s) is MySQL Connector/C++ compatible with? * MySQL Connector/C++ fully supports MySQL Server version 5.1 and later.  File: manual.info, Node: connector-c, Next: connector-ooo, Prev: connector-cpp, Up: connectors-apis 21.6 MySQL Connector/C ====================== * Menu: * connector-c-building:: Building MySQL Connector/C from the Source Code * connector-c-testing:: Testing MySQL Connector/C * connector-c-faq:: MySQL Connector/C FAQ *What is MySQL Connector/C?* MySQL Connector/C is a C client library for client/server communication. It is a standalone replacement for the MySQL Client Library shipped with the MySQL Server. *Why have a replacement for MySQL Client Library?* There is no need to compile or install the MySQL Server package if you only need the client library. MySQL Connector/C does not rely on the MySQL Server release cycle, so bug fixes and new features are released more often. MySQL Connector/C API documentation is available here *Note c-api-functions::. Supported platforms include: * Windows * Windows x64 * Linux * Solaris * FreeBSD * Mac OS X * HP-UX * IBM AIX * IBM i5/OS  File: manual.info, Node: connector-c-building, Next: connector-c-testing, Prev: connector-c, Up: connector-c 21.6.1 Building MySQL Connector/C from the Source Code ------------------------------------------------------ *Obtaining the Source Code* A TAR file containing the source code can be downloaded (http://dev.mysql.com/downloads/connector/c/#downloads) from the MySQL Developers site. You will need to select the source code package from the drop down list. The source code for development releases of the connector can be found at Launchpad. The project home page can be found here (http://launchpad.net/libmysql). The source code for the 1.0 branch can be found here (https://code.launchpad.net/~libmysql-team/libmysql/1.0). To obtain the code you will need to have Bazaar installed and use the command `bzr branch lp:libmysql'. * *Building on Unix* Examples of supported Unix or Unix-like operating systems include: * Solaris * Linux * HP-UX * AIX * OS X *Compiler Tools* Ideally, the native compiler tool set for the target platform is used for compilation. This would be SunStudio for Solaris and aCC for HP-UX for example. However, the GNU tool-chain can be used across all platforms. You also need `CMake' 2.6 or newer, which is available online (http://www.cmake.org). *To Build* If using GNU AutoTools change to the MySQL Connector/C source directory and follow the procedure below. 1. To generate the makefile enter: shell> cmake -G "Unix Makefiles" or for a Debug build enter: shell> cmake -G "Unix Makefiles" -DCMAKE_BUILD_TYPE=Debug 2. Then build the project using: shell> make *To Install* By default make install will install the MySQL Connector/C files in the `/usr/local' directory. You can change this behavior by specifying another directory when generating the `makefile': shell> cmake -G "Unix Makefiles" -DCMAKE_INSTALL_PREFIX=/mypath Now, in the root shell, enter the following to install the MySQL Connector/C libraries and tools: root-shell> make install At this point all of the MySQL Connector/C files will be in place. * *Building on Microsoft Windows* Older versions of Microsoft Windows are not supported. Supported versions are Windows 2000, Windows XP, Windows Vista, Windows Server 2003, or Windows Server 2008. *Compiler Tools* Microsoft Visual Studio 8 and 9 are recommended. The Express Edition of Visual Studio and other compilers may work, but are untested. You also need `CMake' 2.6 or newer, available at http://www.cmake.org *To Build* You need to have the environment variables set for the Visual Studio toolchain. Visual Studio includes a batch file to set these for you, and installs a shortcut into the `Start' menu to open a command prompt with these variables set. Build MySQL Connector/C using the `CMake' command-line tool by entering the following from the source root directory in a command prompt window: shell> cmake -G "Visual Studio 9 2008" This produces a project file that you can open with Visual Studio or build from the command line with either of: shell> devenv.com libmysql.sln /build Release shell> devenv.com libmysql.sln /build RelWithDebInfo For other versions of Visual Studio or `nmake' based build, run the following command: shell> cmake --help to check the supported generators. To compile the Debug build, you must run set the `CMake' build type so the correct version of external libraries are used: shell> cmake -G "Visual Studio 8 2005" -DCMAKE_BUILD_TYPE=Debug Followed by: shell> devenv.com libmysql.sln /build Debug *To Install* To create a install package you can choose between two variants: 1. Creating a Zip package 2. Creating an MSI install package * *Zip package* To create a Zip package, run the `cpack' command from the root of your MySQL Connector/C source directory. * *MSI Install package* The required tools include Windows XML Installer toolset (WIX), which is available online (http://sourceforge.net/projects/wix/). To create the MSI install package change to the subdirectory `win' and generate the `makefile': shell> cmake -G "NMake Makefiles" Create the MSI install package by calling `nmake': shell> nmake *Build Options* The following options can be used when building the MySQL Connector/C source code: Build Option Description -DWITH_OPENSSL=1 Enables dynamic linking to the system OpenSSL library. -DWITH_EXTERNAL_ZLIB=1 Enables dynamic linking to the system Zlib library.  File: manual.info, Node: connector-c-testing, Next: connector-c-faq, Prev: connector-c-building, Up: connector-c 21.6.2 Testing MySQL Connector/C -------------------------------- For testing MySQL Connector/C you will need a running MySQL server instance. Before you run the test suite you need to specify the following environment variables: * `MYSQL_TEST_HOST' (default localhost) * `MYSQL_TEST_USER' * `MYSQL_TEST_PASSWD' * `MYSQL_TEST_PORT' * `MYSQL_TEST_SOCKET' * `MYSQL_TEST_DB' (default test) To run the test suite, execute `ctest' from the command line: shell> ctest  File: manual.info, Node: connector-c-faq, Prev: connector-c-testing, Up: connector-c 21.6.3 MySQL Connector/C FAQ ---------------------------- *Questions* * 21.6.3.1: What is the `MySQL Native C API'? What are its typical benefits and use cases? * 21.6.3.2: What is `libmysql'? * 21.6.3.3: What is `libmysqld'? * 21.6.3.4: What is `MySQL Connector/C'? * 21.6.3.5: What is the difference between `Native C API', `libmysql', `libmysqld' and `MySQL Connector/C'? * 21.6.3.6: Does MySQL Connector/C replace any of `Native C API', `libmysql' and `libmysqld'? *Questions and Answers* *21.6.3.1: ** What is the `MySQL Native C API'? What are its typical benefits and use cases? * MySQL Connector/C, also known as `libmysql', or MySQL Native C API, is a standalone, C-based API and library that you can use in C applications to connect with the MySQL Server. It implements the same MySQL client API that has been in use for a decade. It is also used as the foundation for drivers for standard database APIs such as ODBC, Perl's DBI, and Python's DB API. *21.6.3.2: ** What is `libmysql'? * `libmysql' is the name of the library that MySQL Connector/C provides. *21.6.3.3: ** What is `libmysqld'? * `libmysqld' is an embedded database server with the same API as MySQL Connector/C. It is included with the MySQL Server distribution. *21.6.3.4: ** What is `MySQL Connector/C'? * MySQL Connector/C is a standalone distribution of the `libmysql' library, which was previously only available as part of the MySQL Server distribution. The version of `libmysql' included with MySQL Connector/C and the version bundled with the server are functionally equivalent, but the cross-platform build system for MySQL Connector/C uses `CMake'. *21.6.3.5: ** What is the difference between `Native C API', `libmysql', `libmysqld' and `MySQL Connector/C'? * MySQL Connector/C and `libmysql' are the `native C API for MySQL', and all three terms can be used interchangeably. `libmysqld' is the embedded version of the MySQL Server, and is included in the server distribution. *21.6.3.6: ** Does MySQL Connector/C replace any of `Native C API', `libmysql' and `libmysqld'? * MySQL Connector/C contains `libmysql', and implements a native C API. It does not include `libmysqld', which can be found with the MySQL server distribution.  File: manual.info, Node: connector-ooo, Next: libmysqld, Prev: connector-c, Up: connectors-apis 21.7 MySQL Connector/OpenOffice.org =================================== * Menu: * connector-ooo-installation:: Installation * connector-ooo-getting-started:: Getting Started: Connecting to MySQL * connector-ooo-getting-started-examples:: Getting Started: Usage Examples * connector-ooo-references:: References * connector-ooo-bugs:: Known Bugs * connector-ooo-contact:: Contact MySQL Connector/OpenOffice.org is a native MySQL database connector for OpenOffice.org. Currently, it is in preview status and supports OpenOffice.org 3.1 and above. It can be used to connect OpenOffice.org applications to a MySQL server. Before MySQL Connector/OpenOffice.org became available you would have to use MySQL Connector/J (JDBC) or MySQL Connector/ODBC to connect to a MySQL server. Connector/OpenOffice.org is a community project. The source code for Connector/OpenOffice.org is available under GPL with the FLOSS License Exception. *Advantages* Using MySQL Connector/OpenOffice.org has the following advantages: * Easy installation through the OpenOffice.org Extension Manager. * Seamless integration into OpenOffice.org. * No need to go through an additional Connector installation routine (ODBC/JDBC) * No need to configure or register an additional Connector (ODBC) * No need to install or configure a driver manager (ODBC) *Status* MySQL Connector/OpenOffice.org is currently at version 1.0 GA. If you have any queries please contact us through our mailing list at  File: manual.info, Node: connector-ooo-installation, Next: connector-ooo-getting-started, Prev: connector-ooo, Up: connector-ooo 21.7.1 Installation ------------------- 1. Install or upgrade to OpenOffice.org 3.1. 2. Download MySQL Connector/OpenOffice.org from The OpenOffice.org extension download site (http://extensions.services.openoffice.org/project/mysql_connector). Save the file corresponding to your platform. Currently supported platforms are Windows, Linux, Linux x86-64, Mac OS X, Solaris x86 and Solaris SPARC. 3. Add the `.oxt' extension through the Extension Manager of OpenOffice.org. In OpenOffice.org, select `Tools', `Extension Manager...' and specify the `.oxt' file as a new extension. When done, MySQL Connector/OpenOffice.org will show up as a new extension in the Extension Manager. FIGURE GOES HERE: Adding an Extension 4. Restart OpenOffice.org.  File: manual.info, Node: connector-ooo-getting-started, Next: connector-ooo-getting-started-examples, Prev: connector-ooo-installation, Up: connector-ooo 21.7.2 Getting Started: Connecting to MySQL ------------------------------------------- MySQL Connector/OpenOffice.org enables you to access the MySQL Server and its schemata from the OpenOffice.org suite. The following example demonstrates the creation of a new OpenOffice.org Base database which uses a local MySQL Server for storage and the new connector for connecting. 1. * Select the database* Create a new database by selecting `File', `New', `Database'. This starts a wizard that enables you to create a new database, open an existing database, or connect to an existing database. Select the `Connect to existing database' radio button. From the listbox select MySQL. Click `Next >>'. FIGURE GOES HERE: Selecting the Database 2. You will be asked how you would like to connect to the database. Select the `Connect native' radio button. FIGURE GOES HERE: Selecting the connection type Click `Next >>'. 3. * Fill in the connection settings* Enter the name of the database, server URL, and optionally the socket to connect on (if not using the default). Note that if you do not specify a database all databases will be available for selection. FIGURE GOES HERE: Entering Connection Settings Click `Next >>'. 4. * Set up user authentication* If you are using MySQL server's anonymous account without a password, you do not have to fill in anything in this step. Otherwise, fill in your MySQL user name and check the password check box. Note, for security reasons, you should not normally use the anonymous account without a password. FIGURE GOES HERE: Setting Up User Authentication You can now test your connection to the MySQL database server by clicking the `Test Connection' button. Check the check box if you do not want OpenOffice.org to ask you for your password again in the current session. Testing the connection is optional, although recommended. Click `Next >>'. 5. * Decide how to proceed after connecting to the database * FIGURE GOES HERE: After Connecting to the Database Keep the default settings. Click `Finish'. 6. You will then be prompted to save you database as a database file. Enter the name of the database and the location in which to save the file. FIGURE GOES HERE: Entering the Database File Name Click `Save'. You will be located in the Base application with your database tables displayed.  File: manual.info, Node: connector-ooo-getting-started-examples, Next: connector-ooo-references, Prev: connector-ooo-getting-started, Up: connector-ooo 21.7.3 Getting Started: Usage Examples -------------------------------------- *Listing Tables* In the `Database' area of the `Base' main window, select `Tables'. If this is the first time you are accessing the database you will be prompted for your credentials (user name and password); you can store these settings for your current Base session. FIGURE GOES HERE: Listing Tables Depending on your connection settings you will now see all databases with all their tables, or just the database you have specified in the connection settings.  File: manual.info, Node: connector-ooo-references, Next: connector-ooo-bugs, Prev: connector-ooo-getting-started-examples, Up: connector-ooo 21.7.4 References ----------------- See the OpenOffice.org Web site (http://www.openoffice.org/) for documentation of the office suite and its Extension Manager.  File: manual.info, Node: connector-ooo-bugs, Next: connector-ooo-contact, Prev: connector-ooo-references, Up: connector-ooo 21.7.5 Known Bugs ----------------- If you discover a bug in Connector/OpenOffice.org please add it to this list (http://wiki.services.openoffice.org/wiki/Database/Drivers/MySQL_Native#Known_issues) and send an email to . You need to be logged in with an OpenOffice.org account for both; see the project mailing list (http://dba.openoffice.org/servlets/ProjectMailingListList) for details.  File: manual.info, Node: connector-ooo-contact, Prev: connector-ooo-bugs, Up: connector-ooo 21.7.6 Contact -------------- To discuss the new MySQL Connector/OpenOffice.org, please subscribe to the mailing list . It is a low-volume list with less than 10 mails per day.  File: manual.info, Node: libmysqld, Next: c, Prev: connector-ooo, Up: connectors-apis 21.8 libmysqld, the Embedded MySQL Server Library ================================================= * Menu: * libmysqld-compiling:: Compiling Programs with `libmysqld' * libmysqld-restrictions:: Restrictions When Using the Embedded MySQL Server * libmysqld-options:: Options with the Embedded Server * libmysqld-example:: Embedded Server Examples * libmysqld-licensing:: Licensing the Embedded Server The embedded MySQL server library makes it possible to run a full-featured MySQL server inside a client application. The main benefits are increased speed and more simple management for embedded applications. The embedded server library is based on the client/server version of MySQL, which is written in C/C++. Consequently, the embedded server also is written in C/C++. There is no embedded server available in other languages. The API is identical for the embedded MySQL version and the client/server version. To change an old threaded application to use the embedded library, you normally only have to add calls to the following functions. Function When to Call *Note Should be called before any other MySQL function `mysql_library_init()':is called, preferably early in the `main()' mysql-library-init.function. *Note Should be called before your program exits. `mysql_library_end()': mysql-library-end. *Note Should be called in each thread you create that `mysql_thread_init()':accesses MySQL. mysql-thread-init. *Note Should be called before calling `pthread_exit()' `mysql_thread_end()': mysql-thread-end. Then you must link your code with `libmysqld.a' instead of `libmysqlclient.a'. To ensure binary compatibility between your application and the server library, be sure to compile your application against headers for the same series of MySQL that was used to compile the server library. For example, if `libmysqld' was compiled against MySQL 4.1 headers, do not compile your application against MySQL 5.1 headers, or vice versa. The `mysql_library_XXX()' functions are also included in `libmysqlclient.a' to enable you to change between the embedded and the client/server version by just linking your application with the right library. See *Note mysql-library-init::. One difference between the embedded server and the standalone server is that for the embedded server, authentication for connections is disabled by default. To use authentication for the embedded server, specify the `--with-embedded-privilege-control' option when you invoke `configure' to configure your MySQL distribution.  File: manual.info, Node: libmysqld-compiling, Next: libmysqld-restrictions, Prev: libmysqld, Up: libmysqld 21.8.1 Compiling Programs with `libmysqld' ------------------------------------------ In precompiled binary MySQL distributions that include `libmysqld', the embedded server library, MySQL builds the library using the appropriate vendor compiler if there is one. To get a `libmysqld' library if you build MySQL from source yourself, you should configure MySQL with the `--with-embedded-server' option. See *Note source-configuration-options::. When you link your program with `libmysqld', you must also include the system-specific `pthread' libraries and some libraries that the MySQL server uses. You can get the full list of libraries by executing *Note `mysql_config --libmysqld-libs': mysql-config. The correct flags for compiling and linking a threaded program must be used, even if you do not directly call any thread functions in your code. To compile a C program to include the necessary files to embed the MySQL server library into an executable version of a program, the compiler will need to know where to find various files and need instructions on how to compile the program. The following example shows how a program could be compiled from the command line, assuming that you are using `gcc', use the GNU C compiler: gcc mysql_test.c -o mysql_test -lz \ `/usr/local/mysql/bin/mysql_config --include --libmysqld-libs` Immediately following the `gcc' command is the name of the C program source file. After it, the `-o' option is given to indicate that the file name that follows is the name that the compiler is to give to the output file, the compiled program. The next line of code tells the compiler to obtain the location of the include files and libraries and other settings for the system on which it is compiled. Because of a problem with *Note `mysql_config': mysql-config, the option `-lz' (for compression) is added here. The *Note `mysql_config': mysql-config. command is contained in backticks, not single quotation marks. On some non-`gcc' platforms, the embedded library depends on C++ runtime libraries and linking against the embedded library might result in missing-symbol errors. To solve this, link using a C++ compiler or explicitly list the required libraries on the link command line.  File: manual.info, Node: libmysqld-restrictions, Next: libmysqld-options, Prev: libmysqld-compiling, Up: libmysqld 21.8.2 Restrictions When Using the Embedded MySQL Server -------------------------------------------------------- The embedded server has the following limitations: * No user-defined functions (UDFs). * No stack trace on core dump. * You cannot set this up as a master or a slave (no replication). * Very large result sets may be unusable on low memory systems. * You cannot connect to an embedded server from an outside process with sockets or TCP/IP. However, you can connect to an intermediate application, which in turn can connect to an embedded server on the behalf of a remote client or outside process. * `InnoDB' is not reentrant in the embedded server and cannot be used for multiple connections, either successively or simultaneously. * The Event Scheduler is not available. Because of this, the `event_scheduler' system variable is disabled. Some of these limitations can be changed by editing the `mysql_embed.h' include file and recompiling MySQL.  File: manual.info, Node: libmysqld-options, Next: libmysqld-example, Prev: libmysqld-restrictions, Up: libmysqld 21.8.3 Options with the Embedded Server --------------------------------------- Any options that may be given with the *Note `mysqld': mysqld. server daemon, may be used with an embedded server library. Server options may be given in an array as an argument to the *Note `mysql_library_init()': mysql-library-init, which initializes the server. They also may be given in an option file like `my.cnf'. To specify an option file for a C program, use the `--defaults-file' option as one of the elements of the second argument of the *Note `mysql_library_init()': mysql-library-init. function. See *Note mysql-library-init::, for more information on the *Note `mysql_library_init()': mysql-library-init. function. Using option files can make it easier to switch between a client/server application and one where MySQL is embedded. Put common options under the `[server]' group. These are read by both MySQL versions. Client/server-specific options should go under the `[mysqld]' section. Put options specific to the embedded MySQL server library in the `[embedded]' section. Options specific to applications go under section labeled `[ApplicationName_SERVER]'. See *Note option-files::.  File: manual.info, Node: libmysqld-example, Next: libmysqld-licensing, Prev: libmysqld-options, Up: libmysqld 21.8.4 Embedded Server Examples ------------------------------- These two example programs should work without any changes on a Linux or FreeBSD system. For other operating systems, minor changes are needed, mostly with file paths. These examples are designed to give enough details for you to understand the problem, without the clutter that is a necessary part of a real application. The first example is very straightforward. The second example is a little more advanced with some error checking. The first is followed by a command-line entry for compiling the program. The second is followed by a GNUmake file that may be used for compiling instead. *Example 1* `test1_libmysqld.c' #include #include #include #include "mysql.h" MYSQL *mysql; MYSQL_RES *results; MYSQL_ROW record; static char *server_options[] = \ { "mysql_test", "--defaults-file=my.cnf", NULL }; int num_elements = (sizeof(server_options) / sizeof(char *)) - 1; static char *server_groups[] = { "libmysqld_server", "libmysqld_client", NULL }; int main(void) { mysql_library_init(num_elements, server_options, server_groups); mysql = mysql_init(NULL); mysql_options(mysql, MYSQL_READ_DEFAULT_GROUP, "libmysqld_client"); mysql_options(mysql, MYSQL_OPT_USE_EMBEDDED_CONNECTION, NULL); mysql_real_connect(mysql, NULL,NULL,NULL, "database1", 0,NULL,0); mysql_query(mysql, "SELECT column1, column2 FROM table1"); results = mysql_store_result(mysql); while((record = mysql_fetch_row(results))) { printf("%s - %s \n", record[0], record[1]); } mysql_free_result(results); mysql_close(mysql); mysql_library_end(); return 0; } Here is the command line for compiling the above program: gcc test1_libmysqld.c -o test1_libmysqld -lz \ `/usr/local/mysql/bin/mysql_config --include --libmysqld-libs` *Example 2* To try the example, create an `test2_libmysqld' directory at the same level as the MySQL source directory. Save the `test2_libmysqld.c' source and the `GNUmakefile' in the directory, and run GNU `make' from inside the `test2_libmysqld' directory. `test2_libmysqld.c' /* * A simple example client, using the embedded MySQL server library */ #include #include #include #include MYSQL *db_connect(const char *dbname); void db_disconnect(MYSQL *db); void db_do_query(MYSQL *db, const char *query); const char *server_groups[] = { "test2_libmysqld_SERVER", "embedded", "server", NULL }; int main(int argc, char **argv) { MYSQL *one, *two; /* mysql_library_init() must be called before any other mysql * functions. * * You can use mysql_library_init(0, NULL, NULL), and it * initializes the server using groups = { * "server", "embedded", NULL * }. * * In your $HOME/.my.cnf file, you probably want to put: [test2_libmysqld_SERVER] language = /path/to/source/of/mysql/sql/share/english * You could, of course, modify argc and argv before passing * them to this function. Or you could create new ones in any * way you like. But all of the arguments in argv (except for * argv[0], which is the program name) should be valid options * for the MySQL server. * * If you link this client against the normal mysqlclient * library, this function is just a stub that does nothing. */ mysql_library_init(argc, argv, (char **)server_groups); one = db_connect("test"); two = db_connect(NULL); db_do_query(one, "SHOW TABLE STATUS"); db_do_query(two, "SHOW DATABASES"); mysql_close(two); mysql_close(one); /* This must be called after all other mysql functions */ mysql_library_end(); exit(EXIT_SUCCESS); } static void die(MYSQL *db, char *fmt, ...) { va_list ap; va_start(ap, fmt); vfprintf(stderr, fmt, ap); va_end(ap); (void)putc('\n', stderr); if (db) db_disconnect(db); exit(EXIT_FAILURE); } MYSQL * db_connect(const char *dbname) { MYSQL *db = mysql_init(NULL); if (!db) die(db, "mysql_init failed: no memory"); /* * Notice that the client and server use separate group names. * This is critical, because the server does not accept the * client's options, and vice versa. */ mysql_options(db, MYSQL_READ_DEFAULT_GROUP, "test2_libmysqld_CLIENT"); if (!mysql_real_connect(db, NULL, NULL, NULL, dbname, 0, NULL, 0)) die(db, "mysql_real_connect failed: %s", mysql_error(db)); return db; } void db_disconnect(MYSQL *db) { mysql_close(db); } void db_do_query(MYSQL *db, const char *query) { if (mysql_query(db, query) != 0) goto err; if (mysql_field_count(db) > 0) { MYSQL_RES *res; MYSQL_ROW row, end_row; int num_fields; if (!(res = mysql_store_result(db))) goto err; num_fields = mysql_num_fields(res); while ((row = mysql_fetch_row(res))) { (void)fputs(">> ", stdout); for (end_row = row + num_fields; row < end_row; ++row) (void)printf("%s\t", row ? (char*)*row : "NULL"); (void)fputc('\n', stdout); } (void)fputc('\n', stdout); mysql_free_result(res); } else (void)printf("Affected rows: %lld\n", mysql_affected_rows(db)); return; err: die(db, "db_do_query failed: %s [%s]", mysql_error(db), query); } `GNUmakefile' # This assumes the MySQL software is installed in /usr/local/mysql inc := /usr/local/mysql/include/mysql lib := /usr/local/mysql/lib # If you have not installed the MySQL software yet, try this instead #inc := $(HOME)/mysql-5.1/include #lib := $(HOME)/mysql-5.1/libmysqld CC := gcc CPPFLAGS := -I$(inc) -D_THREAD_SAFE -D_REENTRANT CFLAGS := -g -W -Wall LDFLAGS := -static # You can change -lmysqld to -lmysqlclient to use the # client/server library LDLIBS = -L$(lib) -lmysqld -lz -lm -ldl -lcrypt ifneq (,$(shell grep FreeBSD /COPYRIGHT 2>/dev/null)) # FreeBSD LDFLAGS += -pthread else # Assume Linux LDLIBS += -lpthread endif # This works for simple one-file test programs sources := $(wildcard *.c) objects := $(patsubst %c,%o,$(sources)) targets := $(basename $(sources)) all: $(targets) clean: rm -f $(targets) $(objects) *.core  File: manual.info, Node: libmysqld-licensing, Prev: libmysqld-example, Up: libmysqld 21.8.5 Licensing the Embedded Server ------------------------------------ We encourage everyone to promote free software by releasing code under the GPL or a compatible license. For those who are not able to do this, another option is to purchase a commercial license for the MySQL code from Oracle Corporation. For details, please see http://www.mysql.com/company/legal/licensing/.  File: manual.info, Node: c, Next: apis-php, Prev: libmysqld, Up: connectors-apis 21.9 MySQL C API ================ * Menu: * c-api-data-structures:: C API Data Structures * c-api-function-overview:: C API Function Overview * c-api-functions:: C API Function Descriptions * c-api-prepared-statements:: C API Prepared Statements * c-api-prepared-statement-data-structures:: C API Prepared Statement Data Structures * c-api-prepared-statement-function-overview:: C API Prepared Statement Function Overview * c-api-prepared-statement-functions:: C API Prepared Statement Function Descriptions * c-api-thread-functions:: C API Threaded Function Descriptions * c-api-embedded-server-functions:: C API Embedded Server Function Descriptions * c-api-problems:: Common Questions and Problems When Using the C API * auto-reconnect:: Controlling Automatic Reconnection Behavior * c-api-multiple-queries:: C API Support for Multiple Statement Execution * c-api-prepared-statement-problems:: C API Prepared Statement Problems * c-api-prepared-statement-date-handling:: C API Prepared Statement Handling of Date and Time Values * c-api-prepared-call-statements:: C API Support for Prepared `CALL' Statements * building-clients:: Building Client Programs The C API code is distributed with MySQL. It is included in the `mysqlclient' library and enables C programs to access a database. Many of the clients in the MySQL source distribution are written in C. If you are looking for examples that demonstrate how to use the C API, take a look at these clients. You can find these in the `client' directory in the MySQL source distribution. Most of the other client APIs (all except Connector/J and Connector/NET) use the `mysqlclient' library to communicate with the MySQL server. This means that, for example, you can take advantage of many of the same environment variables that are used by other client programs, because they are referenced from the library. See *Note programs::, for a list of these variables. The client has a maximum communication buffer size. The size of the buffer that is allocated initially (16KB) is automatically increased up to the maximum size (the maximum is 16MB). Because buffer sizes are increased only as demand warrants, simply increasing the default maximum limit does not in itself cause more resources to be used. This size check is mostly a check for erroneous statements and communication packets. The communication buffer must be large enough to contain a single SQL statement (for client-to-server traffic) and one row of returned data (for server-to-client traffic). Each thread's communication buffer is dynamically enlarged to handle any query or row up to the maximum limit. For example, if you have *Note `BLOB': blob. values that contain up to 16MB of data, you must have a communication buffer limit of at least 16MB (in both server and client). The client's default maximum is 16MB, but the default maximum in the server is 1MB. You can increase this by changing the value of the `max_allowed_packet' parameter when the server is started. See *Note server-parameters::. The MySQL server shrinks each communication buffer to `net_buffer_length' bytes after each query. For clients, the size of the buffer associated with a connection is not decreased until the connection is closed, at which time client memory is reclaimed. For programming with threads, see *Note threaded-clients::. For creating a standalone application which includes the "server" and "client" in the same program (and does not communicate with an external MySQL server), see *Note libmysqld::. *Note*: If, after an upgrade, you experience problems with compiled client programs, such as `Commands out of sync' or unexpected core dumps, you probably have used old header or library files when compiling your programs. In this case, you should check the date for your `mysql.h' file and `libmysqlclient.a' library to verify that they are from the new MySQL distribution. If not, recompile your programs with the new headers and libraries. Recompilation might also be necessary for programs compiled against the shared client library if the library major version number has changed (for example from `libmysqlclient.so.15' to `libmysqlclient.so.16'.  File: manual.info, Node: c-api-data-structures, Next: c-api-function-overview, Prev: c, Up: c 21.9.1 C API Data Structures ---------------------------- This section describes C API data structures other than those used for prepared statements. For information about the latter, see *Note c-api-prepared-statement-data-structures::. * `MYSQL' This structure represents a handle to one database connection. It is used for almost all MySQL functions. You should not try to make a copy of a `MYSQL' structure. There is no guarantee that such a copy will be usable. * `MYSQL_RES' This structure represents the result of a query that returns rows (*Note `SELECT': select, *Note `SHOW': show, *Note `DESCRIBE': describe, *Note `EXPLAIN': explain.). The information returned from a query is called the _result set_ in the remainder of this section. * `MYSQL_ROW' This is a type-safe representation of one row of data. It is currently implemented as an array of counted byte strings. (You cannot treat these as null-terminated strings if field values may contain binary data, because such values may contain null bytes internally.) Rows are obtained by calling *Note `mysql_fetch_row()': mysql-fetch-row. * `MYSQL_FIELD' This structure contains information about a field, such as the field's name, type, and size. Its members are described in more detail later in this section. You may obtain the `MYSQL_FIELD' structures for each field by calling *Note `mysql_fetch_field()': mysql-fetch-field. repeatedly. Field values are not part of this structure; they are contained in a `MYSQL_ROW' structure. * `MYSQL_FIELD_OFFSET' This is a type-safe representation of an offset into a MySQL field list. (Used by *Note `mysql_field_seek()': mysql-field-seek.) Offsets are field numbers within a row, beginning at zero. * `my_ulonglong' The type used for the number of rows and for *Note `mysql_affected_rows()': mysql-affected-rows, *Note `mysql_num_rows()': mysql-num-rows, and *Note `mysql_insert_id()': mysql-insert-id. This type provides a range of `0' to `1.84e19'. On some systems, attempting to print a value of type `my_ulonglong' does not work. To print such a value, convert it to `unsigned long' and use a `%lu' print format. Example: printf ("Number of rows: %lu\n", (unsigned long) mysql_num_rows(result)); * `my_bool' A boolean type, for values that are true (nonzero) or false (zero). The `MYSQL_FIELD' structure contains the members described in the following list: * `char * name' The name of the field, as a null-terminated string. If the field was given an alias with an `AS' clause, the value of `name' is the alias. * `char * org_name' The name of the field, as a null-terminated string. Aliases are ignored. * `char * table' The name of the table containing this field, if it isn't a calculated field. For calculated fields, the `table' value is an empty string. If the column is selected from a view, `table' names the view. If the table or view was given an alias with an `AS' clause, the value of `table' is the alias. For a *Note `UNION': union, the value is the empty string. * `char * org_table' The name of the table, as a null-terminated string. Aliases are ignored. If the column is selected from a view, `org_table' names the underlying table. For a *Note `UNION': union, the value is the empty string. * `char * db' The name of the database that the field comes from, as a null-terminated string. If the field is a calculated field, `db' is an empty string. For a *Note `UNION': union, the value is the empty string. * `char * catalog' The catalog name. This value is always `"def"'. * `char * def' The default value of this field, as a null-terminated string. This is set only if you use *Note `mysql_list_fields()': mysql-list-fields. * `unsigned long length' The width of the field. This corresponds to the display length, in bytes. The server determines the `length' value before it generates the result set, so this is the minimum length required for a data type capable of holding the largest possible value from the result column, without knowing in advance the actual values that will be produced by the query for the result set. * `unsigned long max_length' The maximum width of the field for the result set (the length in bytes of the longest field value for the rows actually in the result set). If you use *Note `mysql_store_result()': mysql-store-result. or *Note `mysql_list_fields()': mysql-list-fields, this contains the maximum length for the field. If you use *Note `mysql_use_result()': mysql-use-result, the value of this variable is zero. The value of `max_length' is the length of the string representation of the values in the result set. For example, if you retrieve a *Note `FLOAT': numeric-types. column and the `widest' value is `-12.345', `max_length' is 7 (the length of `'-12.345''). If you are using prepared statements, `max_length' is not set by default because for the binary protocol the lengths of the values depend on the types of the values in the result set. (See *Note c-api-prepared-statement-data-structures::.) If you want the `max_length' values anyway, enable the `STMT_ATTR_UPDATE_MAX_LENGTH' option with *Note `mysql_stmt_attr_set()': mysql-stmt-attr-set. and the lengths will be set when you call *Note `mysql_stmt_store_result()': mysql-stmt-store-result. (See *Note mysql-stmt-attr-set::, and *Note mysql-stmt-store-result::.) * `unsigned int name_length' The length of `name'. * `unsigned int org_name_length' The length of `org_name'. * `unsigned int table_length' The length of `table'. * `unsigned int org_table_length' The length of `org_table'. * `unsigned int db_length' The length of `db'. * `unsigned int catalog_length' The length of `catalog'. * `unsigned int def_length' The length of `def'. * `unsigned int flags' Bit-flags that describe the field. The `flags' value may have zero or more of the bits set that are shown in the following table. Flag Value Flag Description `NOT_NULL_FLAG' Field can't be `NULL' `PRI_KEY_FLAG' Field is part of a primary key `UNIQUE_KEY_FLAG' Field is part of a unique key `MULTIPLE_KEY_FLAG' Field is part of a nonunique key `UNSIGNED_FLAG' Field has the `UNSIGNED' attribute `ZEROFILL_FLAG' Field has the `ZEROFILL' attribute `BINARY_FLAG' Field has the `BINARY' attribute `AUTO_INCREMENT_FLAG' Field has the `AUTO_INCREMENT' attribute `NUM_FLAG' Field is numeric `ENUM_FLAG' Field is an *Note `ENUM': enum. (deprecated) `SET_FLAG' Field is a *Note `SET': set. (deprecated) `BLOB_FLAG' Field is a *Note `BLOB': blob. or *Note `TEXT': blob. (deprecated) `TIMESTAMP_FLAG' Field is a *Note `TIMESTAMP': datetime. (deprecated) `NO_DEFAULT_VALUE_FLAG' Field has no default value; see additional notes following table Some of these flags indicate data type information and are superseded by or used in conjunction with the `MYSQL_TYPE_XXX' value in the `field->type' member described later: * To check for *Note `BLOB': blob. or *Note `TIMESTAMP': datetime. values, check whether `type' is `MYSQL_TYPE_BLOB' or `MYSQL_TYPE_TIMESTAMP'. (The `BLOB_FLAG' and `TIMESTAMP_FLAG' flags are unneeded.) * *Note `ENUM': enum. and *Note `SET': set. values are returned as strings. For these, check that the `type' value is `MYSQL_TYPE_STRING' and that the `ENUM_FLAG' or `SET_FLAG' flag is set in the `flags' value. `NUM_FLAG' indicates that a column is numeric. This includes columns with a type of `MYSQL_TYPE_DECIMAL', `MYSQL_TYPE_TINY', `MYSQL_TYPE_SHORT', `MYSQL_TYPE_LONG', `MYSQL_TYPE_FLOAT', `MYSQL_TYPE_DOUBLE', `MYSQL_TYPE_NULL', `MYSQL_TYPE_LONGLONG', `MYSQL_TYPE_INT24', and `MYSQL_TYPE_YEAR'. `NO_DEFAULT_VALUE_FLAG' indicates that a column has no `DEFAULT' clause in its definition. This does not apply to `NULL' columns (because such columns have a default of `NULL'), or to `AUTO_INCREMENT' columns (which have an implied default value). The following example illustrates a typical use of the `flags' value: if (field->flags & NOT_NULL_FLAG) printf("Field can't be null\n"); You may use the convenience macros shown in the following table to determine the boolean status of the `flags' value. Flag Status Description `IS_NOT_NULL(flags)' True if this field is defined as `NOT NULL' `IS_PRI_KEY(flags)' True if this field is a primary key `IS_BLOB(flags)' True if this field is a *Note `BLOB': blob. or *Note `TEXT': blob. (deprecated; test `field->type' instead) * `unsigned int decimals' The number of decimals for numeric fields. * `unsigned int charsetnr' An ID number that indicates the character set/collation pair for the field. To distinguish between binary and nonbinary data for string data types, check whether the `charsetnr' value is 63. If so, the character set is `binary', which indicates binary rather than nonbinary data. This enables you to distinguish *Note `BINARY': binary-varbinary. from *Note `CHAR': char, *Note `VARBINARY': binary-varbinary. from *Note `VARCHAR': char, and the *Note `BLOB': blob. types from the *Note `TEXT': blob. types. `charsetnr' values are the same as those displayed in the `Id' column of the *Note `SHOW COLLATION': show-collation. statement or the `ID' column of the `INFORMATION_SCHEMA' *Note `COLLATIONS': collations-table. table. You can use those information sources to see which character set and collation specific `charsetnr' values indicate: mysql> SHOW COLLATION WHERE Id = 63; +-----------+---------+----+---------+----------+---------+ | Collation | Charset | Id | Default | Compiled | Sortlen | +-----------+---------+----+---------+----------+---------+ | binary | binary | 63 | Yes | Yes | 1 | +-----------+---------+----+---------+----------+---------+ mysql> SELECT COLLATION_NAME, CHARACTER_SET_NAME -> FROM INFORMATION_SCHEMA.COLLATIONS WHERE ID = 33; +-----------------+--------------------+ | COLLATION_NAME | CHARACTER_SET_NAME | +-----------------+--------------------+ | utf8_general_ci | utf8 | +-----------------+--------------------+ * `enum enum_field_types type' The type of the field. The `type' value may be one of the `MYSQL_TYPE_' symbols shown in the following table. Type Value Type Description `MYSQL_TYPE_TINY' *Note `TINYINT': numeric-types. field `MYSQL_TYPE_SHORT' *Note `SMALLINT': numeric-types. field `MYSQL_TYPE_LONG' *Note `INTEGER': numeric-types. field `MYSQL_TYPE_INT24' *Note `MEDIUMINT': numeric-types. field `MYSQL_TYPE_LONGLONG' *Note `BIGINT': numeric-types. field `MYSQL_TYPE_DECIMAL' *Note `DECIMAL': numeric-types. or *Note `NUMERIC': numeric-types. field `MYSQL_TYPE_NEWDECIMAL' Precision math *Note `DECIMAL': numeric-types. or *Note `NUMERIC': numeric-types. `MYSQL_TYPE_FLOAT' *Note `FLOAT': numeric-types. field `MYSQL_TYPE_DOUBLE' *Note `DOUBLE': numeric-types. or *Note `REAL': numeric-types. field `MYSQL_TYPE_BIT' *Note `BIT': numeric-types. field `MYSQL_TYPE_TIMESTAMP' *Note `TIMESTAMP': datetime. field `MYSQL_TYPE_DATE' *Note `DATE': datetime. field `MYSQL_TYPE_TIME' *Note `TIME': time. field `MYSQL_TYPE_DATETIME' *Note `DATETIME': datetime. field `MYSQL_TYPE_YEAR' *Note `YEAR': year. field `MYSQL_TYPE_STRING' *Note `CHAR': char. or *Note `BINARY': binary-varbinary. field `MYSQL_TYPE_VAR_STRING' *Note `VARCHAR': char. or *Note `VARBINARY': binary-varbinary. field `MYSQL_TYPE_BLOB' *Note `BLOB': blob. or *Note `TEXT': blob. field (use `max_length' to determine the maximum length) `MYSQL_TYPE_SET' *Note `SET': set. field `MYSQL_TYPE_ENUM' *Note `ENUM': enum. field `MYSQL_TYPE_GEOMETRY' Spatial field `MYSQL_TYPE_NULL' `NULL'-type field You can use the `IS_NUM()' macro to test whether a field has a numeric type. Pass the `type' value to `IS_NUM()' and it evaluates to TRUE if the field is numeric: if (IS_NUM(field->type)) printf("Field is numeric\n"); *Note `ENUM': enum. and *Note `SET': set. values are returned as strings. For these, check that the `type' value is `MYSQL_TYPE_STRING' and that the `ENUM_FLAG' or `SET_FLAG' flag is set in the `flags' value.  File: manual.info, Node: c-api-function-overview, Next: c-api-functions, Prev: c-api-data-structures, Up: c 21.9.2 C API Function Overview ------------------------------ The functions available in the C API are summarized here and described in greater detail in a later section. See *Note c-api-functions::. *C API Function Names and Descriptions* Function Description *Note `my_init()': Initialize global variables, and thread handler my-init. in thread-safe programs *Note Returns the number of rows `mysql_affected_rows()':changed/deleted/inserted by the last *Note mysql-affected-rows. `UPDATE': update, *Note `DELETE': delete, or *Note `INSERT': insert. query *Note Toggles autocommit mode on/off `mysql_autocommit()': mysql-autocommit. *Note Changes user and database on an open connection `mysql_change_user()': mysql-change-user. *Note Return default character set name for current `mysql_character_set_name()':connection mysql-character-set-name. *Note `mysql_close()': Closes a server connection mysql-close. *Note Commits the transaction `mysql_commit()': mysql-commit. *Note Connects to a MySQL server (this function is `mysql_connect()': deprecated; use *Note `mysql_real_connect()': mysql-connect. mysql-real-connect. instead) *Note Creates a database (this function is deprecated; `mysql_create_db()': use the SQL statement *Note `CREATE DATABASE': mysql-create-db. create-database. instead) *Note Seeks to an arbitrary row number in a query `mysql_data_seek()': result set mysql-data-seek. *Note `mysql_debug()': Does a `DBUG_PUSH' with the given string mysql-debug. *Note Drops a database (this function is deprecated; `mysql_drop_db()': use the SQL statement *Note `DROP DATABASE': mysql-drop-db. drop-database. instead) *Note Makes the server write debug information to the `mysql_dump_debug_info()':log mysql-dump-debug-info. *Note `mysql_eof()': Determines whether the last row of a result set mysql-eof. has been read (this function is deprecated; *Note `mysql_errno()': mysql-errno. or *Note `mysql_error()': mysql-error. may be used instead) *Note `mysql_errno()': Returns the error number for the most recently mysql-errno. invoked MySQL function *Note `mysql_error()': Returns the error message for the most recently mysql-error. invoked MySQL function *Note Escapes special characters in a string for use `mysql_escape_string()':in an SQL statement mysql-escape-string. *Note Returns the type of the next table field `mysql_fetch_field()': mysql-fetch-field. *Note Returns the type of a table field, given a field `mysql_fetch_field_direct()':number mysql-fetch-field-direct. *Note Returns an array of all field structures `mysql_fetch_fields()': mysql-fetch-fields. *Note Returns the lengths of all columns in the `mysql_fetch_lengths()':current row mysql-fetch-lengths. *Note Fetches the next row from the result set `mysql_fetch_row()': mysql-fetch-row. *Note Returns the number of result columns for the `mysql_field_count()': most recent statement mysql-field-count. *Note Puts the column cursor on a specified column `mysql_field_seek()': mysql-field-seek. *Note Returns the position of the field cursor used `mysql_field_tell()': for the last *Note `mysql_fetch_field()': mysql-field-tell. mysql-fetch-field. *Note Frees memory used by a result set `mysql_free_result()': mysql-free-result. *Note Return information about default character set `mysql_get_character_set_info()': mysql-get-character-set-info. *Note Returns client version information as a string `mysql_get_client_info()': mysql-get-client-info. *Note Returns client version information as an integer `mysql_get_client_version()': mysql-get-client-version. *Note Returns a string describing the connection `mysql_get_host_info()': mysql-get-host-info. *Note Returns the protocol version used by the `mysql_get_proto_info()':connection mysql-get-proto-info. *Note Returns the server version number `mysql_get_server_info()': mysql-get-server-info. *Note Returns version number of server as an integer `mysql_get_server_version()': mysql-get-server-version. *Note Return current SSL cipher `mysql_get_ssl_cipher()': mysql-get-ssl-cipher. *Note Encode string in hexadecimal format `mysql_hex_string()': mysql-hex-string. *Note `mysql_info()': Returns information about the most recently mysql-info. executed query *Note `mysql_init()': Gets or initializes a `MYSQL' structure mysql-init. *Note Returns the ID generated for an `AUTO_INCREMENT' `mysql_insert_id()': column by the previous query mysql-insert-id. *Note `mysql_kill()': Kills a given thread mysql-kill. *Note Finalize the MySQL C API library `mysql_library_end()': mysql-library-end. *Note Initialize the MySQL C API library `mysql_library_init()': mysql-library-init. *Note Returns database names matching a simple regular `mysql_list_dbs()': expression mysql-list-dbs. *Note Returns field names matching a simple regular `mysql_list_fields()': expression mysql-list-fields. *Note Returns a list of the current server threads `mysql_list_processes()': mysql-list-processes. *Note Returns table names matching a simple regular `mysql_list_tables()': expression mysql-list-tables. *Note Checks whether any more results exist `mysql_more_results()': mysql-more-results. *Note Returns/initiates the next result in `mysql_next_result()': multiple-result executions mysql-next-result. *Note Returns the number of columns in a result set `mysql_num_fields()': mysql-num-fields. *Note Returns the number of rows in a result set `mysql_num_rows()': mysql-num-rows. *Note Sets connect options for *Note `mysql_options()': `mysql_real_connect()': mysql-real-connect. mysql-options. *Note `mysql_ping()': Checks whether the connection to the server is mysql-ping. working, reconnecting as necessary *Note `mysql_query()': Executes an SQL query specified as a mysql-query. null-terminated string *Note Connects to a MySQL server `mysql_real_connect()': mysql-real-connect. *Note Escapes special characters in a string for use `mysql_real_escape_string()':in an SQL statement, taking into account the mysql-real-escape-string.current character set of the connection *Note Executes an SQL query specified as a counted `mysql_real_query()': string mysql-real-query. *Note Flush or reset tables and caches `mysql_refresh()': mysql-refresh. *Note Tells the server to reload the grant tables `mysql_reload()': mysql-reload. *Note Rolls back the transaction `mysql_rollback()': mysql-rollback. *Note Seeks to a row offset in a result set, using `mysql_row_seek()': value returned from *Note `mysql_row_tell()': mysql-row-seek. mysql-row-tell. *Note Returns the row cursor position `mysql_row_tell()': mysql-row-tell. *Note Selects a database `mysql_select_db()': mysql-select-db. *Note Finalize the MySQL C API library `mysql_server_end()': mysql-server-end. *Note Initialize the MySQL C API library `mysql_server_init()': mysql-server-init. *Note Set default character set for current connection `mysql_set_character_set()': mysql-set-character-set. *Note Set the *Note `LOAD DATA LOCAL INFILE': `mysql_set_local_infile_default()':load-data. handler callbacks to their default mysql-set-local-infile-default.values *Note Install application-specific *Note `LOAD DATA `mysql_set_local_infile_handler()':LOCAL INFILE': load-data. handler callbacks mysql-set-local-infile-handler. *Note Sets an option for the connection (like `mysql_set_server_option()':`multi-statements') mysql-set-server-option. *Note Returns the SQLSTATE error code for the last `mysql_sqlstate()': error mysql-sqlstate. *Note Shuts down the database server `mysql_shutdown()': mysql-shutdown. *Note Prepare to establish SSL connection to server `mysql_ssl_set()': mysql-ssl-set. *Note `mysql_stat()': Returns the server status as a string mysql-stat. *Note Retrieves a complete result set to the client `mysql_store_result()': mysql-store-result. *Note Finalize thread handler `mysql_thread_end()': mysql-thread-end. *Note Returns the current thread ID `mysql_thread_id()': mysql-thread-id. *Note Initialize thread handler `mysql_thread_init()': mysql-thread-init. *Note Returns 1 if the clients are compiled as `mysql_thread_safe()': thread-safe mysql-thread-safe. *Note Initiates a row-by-row result set retrieval `mysql_use_result()': mysql-use-result. *Note Returns the warning count for the previous SQL `mysql_warning_count()':statement mysql-warning-count. Application programs should use this general outline for interacting with MySQL: 1. Initialize the MySQL library by calling *Note `mysql_library_init()': mysql-library-init. This function exists in both the `mysqlclient' C client library and the `mysqld' embedded server library, so it is used whether you build a regular client program by linking with the `-libmysqlclient' flag, or an embedded server application by linking with the `-libmysqld' flag. 2. Initialize a connection handler by calling *Note `mysql_init()': mysql-init. and connect to the server by calling *Note `mysql_real_connect()': mysql-real-connect. 3. Issue SQL statements and process their results. (The following discussion provides more information about how to do this.) 4. Close the connection to the MySQL server by calling *Note `mysql_close()': mysql-close. 5. End use of the MySQL library by calling *Note `mysql_library_end()': mysql-library-end. The purpose of calling *Note `mysql_library_init()': mysql-library-init. and *Note `mysql_library_end()': mysql-library-end. is to provide proper initialization and finalization of the MySQL library. For applications that are linked with the client library, they provide improved memory management. If you don't call *Note `mysql_library_end()': mysql-library-end, a block of memory remains allocated. (This does not increase the amount of memory used by the application, but some memory leak detectors will complain about it.) For applications that are linked with the embedded server, these calls start and stop the server. In a nonmulti-threaded environment, the call to *Note `mysql_library_init()': mysql-library-init. may be omitted, because *Note `mysql_init()': mysql-init. will invoke it automatically as necessary. However, *Note `mysql_library_init()': mysql-library-init. is not thread-safe in a multi-threaded environment, and thus neither is *Note `mysql_init()': mysql-init, which calls *Note `mysql_library_init()': mysql-library-init. You must either call *Note `mysql_library_init()': mysql-library-init. prior to spawning any threads, or else use a mutex to protect the call, whether you invoke *Note `mysql_library_init()': mysql-library-init. or indirectly through *Note `mysql_init()': mysql-init. This should be done prior to any other client library call. To connect to the server, call *Note `mysql_init()': mysql-init. to initialize a connection handler, then call *Note `mysql_real_connect()': mysql-real-connect. with that handler (along with other information such as the host name, user name, and password). Upon connection, *Note `mysql_real_connect()': mysql-real-connect. sets the `reconnect' flag (part of the `MYSQL' structure) to a value of `1' in versions of the API older than 5.0.3, or `0' in newer versions. A value of `1' for this flag indicates that if a statement cannot be performed because of a lost connection, to try reconnecting to the server before giving up. You can use the `MYSQL_OPT_RECONNECT' option to *Note `mysql_options()': mysql-options. to control reconnection behavior. When you are done with the connection, call *Note `mysql_close()': mysql-close. to terminate it. While a connection is active, the client may send SQL statements to the server using *Note `mysql_query()': mysql-query. or *Note `mysql_real_query()': mysql-real-query. The difference between the two is that *Note `mysql_query()': mysql-query. expects the query to be specified as a null-terminated string whereas *Note `mysql_real_query()': mysql-real-query. expects a counted string. If the string contains binary data (which may include null bytes), you must use *Note `mysql_real_query()': mysql-real-query. For each non-*Note `SELECT': select. query (for example, *Note `INSERT': insert, *Note `UPDATE': update, *Note `DELETE': delete.), you can find out how many rows were changed (affected) by calling *Note `mysql_affected_rows()': mysql-affected-rows. For *Note `SELECT': select. queries, you retrieve the selected rows as a result set. (Note that some statements are *Note `SELECT': select.-like in that they return rows. These include *Note `SHOW': show, *Note `DESCRIBE': describe, and *Note `EXPLAIN': explain. They should be treated the same way as *Note `SELECT': select. statements.) There are two ways for a client to process result sets. One way is to retrieve the entire result set all at once by calling *Note `mysql_store_result()': mysql-store-result. This function acquires from the server all the rows returned by the query and stores them in the client. The second way is for the client to initiate a row-by-row result set retrieval by calling *Note `mysql_use_result()': mysql-use-result. This function initializes the retrieval, but does not actually get any rows from the server. In both cases, you access rows by calling *Note `mysql_fetch_row()': mysql-fetch-row. With *Note `mysql_store_result()': mysql-store-result, *Note `mysql_fetch_row()': mysql-fetch-row. accesses rows that have previously been fetched from the server. With *Note `mysql_use_result()': mysql-use-result, *Note `mysql_fetch_row()': mysql-fetch-row. actually retrieves the row from the server. Information about the size of the data in each row is available by calling *Note `mysql_fetch_lengths()': mysql-fetch-lengths. After you are done with a result set, call *Note `mysql_free_result()': mysql-free-result. to free the memory used for it. The two retrieval mechanisms are complementary. Client programs should choose the approach that is most appropriate for their requirements. In practice, clients tend to use *Note `mysql_store_result()': mysql-store-result. more commonly. An advantage of *Note `mysql_store_result()': mysql-store-result. is that because the rows have all been fetched to the client, you not only can access rows sequentially, you can move back and forth in the result set using *Note `mysql_data_seek()': mysql-data-seek. or *Note `mysql_row_seek()': mysql-row-seek. to change the current row position within the result set. You can also find out how many rows there are by calling *Note `mysql_num_rows()': mysql-num-rows. On the other hand, the memory requirements for *Note `mysql_store_result()': mysql-store-result. may be very high for large result sets and you are more likely to encounter out-of-memory conditions. An advantage of *Note `mysql_use_result()': mysql-use-result. is that the client requires less memory for the result set because it maintains only one row at a time (and because there is less allocation overhead, *Note `mysql_use_result()': mysql-use-result. can be faster). Disadvantages are that you must process each row quickly to avoid tying up the server, you don't have random access to rows within the result set (you can only access rows sequentially), and you don't know how many rows are in the result set until you have retrieved them all. Furthermore, you _must_ retrieve all the rows even if you determine in mid-retrieval that you've found the information you were looking for. The API makes it possible for clients to respond appropriately to statements (retrieving rows only as necessary) without knowing whether the statement is a *Note `SELECT': select. You can do this by calling *Note `mysql_store_result()': mysql-store-result. after each *Note `mysql_query()': mysql-query. (or *Note `mysql_real_query()': mysql-real-query.). If the result set call succeeds, the statement was a *Note `SELECT': select. and you can read the rows. If the result set call fails, call *Note `mysql_field_count()': mysql-field-count. to determine whether a result was actually to be expected. If *Note `mysql_field_count()': mysql-field-count. returns zero, the statement returned no data (indicating that it was an *Note `INSERT': insert, *Note `UPDATE': update, *Note `DELETE': delete, and so forth), and was not expected to return rows. If *Note `mysql_field_count()': mysql-field-count. is nonzero, the statement should have returned rows, but didn't. This indicates that the statement was a *Note `SELECT': select. that failed. See the description for *Note `mysql_field_count()': mysql-field-count. for an example of how this can be done. Both *Note `mysql_store_result()': mysql-store-result. and *Note `mysql_use_result()': mysql-use-result. enable you to obtain information about the fields that make up the result set (the number of fields, their names and types, and so forth). You can access field information sequentially within the row by calling *Note `mysql_fetch_field()': mysql-fetch-field. repeatedly, or by field number within the row by calling *Note `mysql_fetch_field_direct()': mysql-fetch-field-direct. The current field cursor position may be changed by calling *Note `mysql_field_seek()': mysql-field-seek. Setting the field cursor affects subsequent calls to *Note `mysql_fetch_field()': mysql-fetch-field. You can also get information for fields all at once by calling *Note `mysql_fetch_fields()': mysql-fetch-fields. For detecting and reporting errors, MySQL provides access to error information by means of the *Note `mysql_errno()': mysql-errno. and *Note `mysql_error()': mysql-error. functions. These return the error code or error message for the most recently invoked function that can succeed or fail, enabling you to determine when an error occurred and what it was.  File: manual.info, Node: c-api-functions, Next: c-api-prepared-statements, Prev: c-api-function-overview, Up: c 21.9.3 C API Function Descriptions ---------------------------------- * Menu: * mysql-affected-rows:: `mysql_affected_rows()' * mysql-autocommit:: `mysql_autocommit()' * mysql-change-user:: `mysql_change_user()' * mysql-character-set-name:: `mysql_character_set_name()' * mysql-close:: `mysql_close()' * mysql-commit:: `mysql_commit()' * mysql-connect:: `mysql_connect()' * mysql-create-db:: `mysql_create_db()' * mysql-data-seek:: `mysql_data_seek()' * mysql-debug:: `mysql_debug()' * mysql-drop-db:: `mysql_drop_db()' * mysql-dump-debug-info:: `mysql_dump_debug_info()' * mysql-eof:: `mysql_eof()' * mysql-errno:: `mysql_errno()' * mysql-error:: `mysql_error()' * mysql-escape-string:: `mysql_escape_string()' * mysql-fetch-field:: `mysql_fetch_field()' * mysql-fetch-field-direct:: `mysql_fetch_field_direct()' * mysql-fetch-fields:: `mysql_fetch_fields()' * mysql-fetch-lengths:: `mysql_fetch_lengths()' * mysql-fetch-row:: `mysql_fetch_row()' * mysql-field-count:: `mysql_field_count()' * mysql-field-seek:: `mysql_field_seek()' * mysql-field-tell:: `mysql_field_tell()' * mysql-free-result:: `mysql_free_result()' * mysql-get-character-set-info:: `mysql_get_character_set_info()' * mysql-get-client-info:: `mysql_get_client_info()' * mysql-get-client-version:: `mysql_get_client_version()' * mysql-get-host-info:: `mysql_get_host_info()' * mysql-get-proto-info:: `mysql_get_proto_info()' * mysql-get-server-info:: `mysql_get_server_info()' * mysql-get-server-version:: `mysql_get_server_version()' * mysql-get-ssl-cipher:: `mysql_get_ssl_cipher()' * mysql-hex-string:: `mysql_hex_string()' * mysql-info:: `mysql_info()' * mysql-init:: `mysql_init()' * mysql-insert-id:: `mysql_insert_id()' * mysql-kill:: `mysql_kill()' * mysql-library-end:: `mysql_library_end()' * mysql-library-init:: `mysql_library_init()' * mysql-list-dbs:: `mysql_list_dbs()' * mysql-list-fields:: `mysql_list_fields()' * mysql-list-processes:: `mysql_list_processes()' * mysql-list-tables:: `mysql_list_tables()' * mysql-more-results:: `mysql_more_results()' * mysql-next-result:: `mysql_next_result()' * mysql-num-fields:: `mysql_num_fields()' * mysql-num-rows:: `mysql_num_rows()' * mysql-options:: `mysql_options()' * mysql-ping:: `mysql_ping()' * mysql-query:: `mysql_query()' * mysql-real-connect:: `mysql_real_connect()' * mysql-real-escape-string:: `mysql_real_escape_string()' * mysql-real-query:: `mysql_real_query()' * mysql-refresh:: `mysql_refresh()' * mysql-reload:: `mysql_reload()' * mysql-rollback:: `mysql_rollback()' * mysql-row-seek:: `mysql_row_seek()' * mysql-row-tell:: `mysql_row_tell()' * mysql-select-db:: `mysql_select_db()' * mysql-set-character-set:: `mysql_set_character_set()' * mysql-set-local-infile-default:: `mysql_set_local_infile_default()' * mysql-set-local-infile-handler:: `mysql_set_local_infile_handler()' * mysql-set-server-option:: `mysql_set_server_option()' * mysql-shutdown:: `mysql_shutdown()' * mysql-sqlstate:: `mysql_sqlstate()' * mysql-ssl-set:: `mysql_ssl_set()' * mysql-stat:: `mysql_stat()' * mysql-store-result:: `mysql_store_result()' * mysql-thread-id:: `mysql_thread_id()' * mysql-use-result:: `mysql_use_result()' * mysql-warning-count:: `mysql_warning_count()' In the descriptions here, a parameter or return value of `NULL' means `NULL' in the sense of the C programming language, not a MySQL `NULL' value. Functions that return a value generally return a pointer or an integer. Unless specified otherwise, functions returning a pointer return a non-`NULL' value to indicate success or a `NULL' value to indicate an error, and functions returning an integer return zero to indicate success or nonzero to indicate an error. Note that `nonzero' means just that. Unless the function description says otherwise, do not test against a value other than zero: if (result) /* correct */ ... error ... if (result < 0) /* incorrect */ ... error ... if (result == -1) /* incorrect */ ... error ... When a function returns an error, the *Errors* subsection of the function description lists the possible types of errors. You can find out which of these occurred by calling *Note `mysql_errno()': mysql-errno. A string representation of the error may be obtained by calling *Note `mysql_error()': mysql-error.  File: manual.info, Node: mysql-affected-rows, Next: mysql-autocommit, Prev: c-api-functions, Up: c-api-functions 21.9.3.1 `mysql_affected_rows()' ................................ `my_ulonglong mysql_affected_rows(MYSQL *mysql)' * Description * *Note `mysql_affected_rows()': mysql-affected-rows. may be called immediately after executing a statement with *Note `mysql_query()': mysql-query. or *Note `mysql_real_query()': mysql-real-query. It returns the number of rows changed, deleted, or inserted by the last statement if it was an *Note `UPDATE': update, *Note `DELETE': delete, or *Note `INSERT': insert. For *Note `SELECT': select. statements, *Note `mysql_affected_rows()': mysql-affected-rows. works like *Note `mysql_num_rows()': mysql-num-rows. For *Note `UPDATE': update. statements, the affected-rows value by default is the number of rows actually changed. If you specify the `CLIENT_FOUND_ROWS' flag to *Note `mysql_real_connect()': mysql-real-connect. when connecting to *Note `mysqld': mysqld, the affected-rows value is the number of rows `found'; that is, matched by the `WHERE' clause. For *Note `REPLACE': replace. statements, the affected-rows value is 2 if the new row replaced an old row, because in this case, one row was inserted after the duplicate was deleted. For *Note `INSERT ... ON DUPLICATE KEY UPDATE': insert-on-duplicate. statements, the affected-rows value is 1 if the row is inserted as a new row and 2 if an existing row is updated. Following a *Note `CALL': call. statement for a stored procedure, *Note `mysql_affected_rows()': mysql-affected-rows. returns the value that it would return for the last statement executed within the procedure, or `0' if that statement would return `-1'. Within the procedure, you can use `ROW_COUNT()' at the SQL level to obtain the affected-rows value for individual statements. * Return Values * An integer greater than zero indicates the number of rows affected or retrieved. Zero indicates that no records were updated for an *Note `UPDATE': update. statement, no rows matched the `WHERE' clause in the query or that no query has yet been executed. -1 indicates that the query returned an error or that, for a *Note `SELECT': select. query, *Note `mysql_affected_rows()': mysql-affected-rows. was called prior to calling *Note `mysql_store_result()': mysql-store-result. Because *Note `mysql_affected_rows()': mysql-affected-rows. returns an unsigned value, you can check for -1 by comparing the return value to `(my_ulonglong)-1' (or to `(my_ulonglong)~0', which is equivalent). * Errors * None. * Example * char *stmt = "UPDATE products SET cost=cost*1.25 WHERE group=10"; mysql_query(&mysql,stmt); printf("%ld products updated", (long) mysql_affected_rows(&mysql));  File: manual.info, Node: mysql-autocommit, Next: mysql-change-user, Prev: mysql-affected-rows, Up: c-api-functions 21.9.3.2 `mysql_autocommit()' ............................. `my_bool mysql_autocommit(MYSQL *mysql, my_bool mode)' * Description * Sets autocommit mode on if `mode' is 1, off if `mode' is 0. * Return Values * Zero if successful. Nonzero if an error occurred. * Errors * None.  File: manual.info, Node: mysql-change-user, Next: mysql-character-set-name, Prev: mysql-autocommit, Up: c-api-functions 21.9.3.3 `mysql_change_user()' .............................. `my_bool mysql_change_user(MYSQL *mysql, const char *user, const char *password, const char *db)' * Description * Changes the user and causes the database specified by `db' to become the default (current) database on the connection specified by `mysql'. In subsequent queries, this database is the default for table references that do not include an explicit database specifier. *Note `mysql_change_user()': mysql-change-user. fails if the connected user cannot be authenticated or doesn't have permission to use the database. In this case, the user and database are not changed. The `db' parameter may be set to `NULL' if you don't want to have a default database. This command resets the state as if one had done a new connect. (See *Note auto-reconnect::.) It always performs a *Note `ROLLBACK': commit. of any active transactions, closes and drops all temporary tables, and unlocks all locked tables. Session system variables are reset to the values of the corresponding global system variables. Prepared statements are released and *Note `HANDLER': handler. variables are closed. Locks acquired with `GET_LOCK()' are released. These effects occur even if the user didn't change. * Return Values * Zero for success. Nonzero if an error occurred. * Errors * The same that you can get from *Note `mysql_real_connect()': mysql-real-connect. * `CR_COMMANDS_OUT_OF_SYNC' Commands were executed in an improper order. * `CR_SERVER_GONE_ERROR' The MySQL server has gone away. * `CR_SERVER_LOST' The connection to the server was lost during the query. * `CR_UNKNOWN_ERROR' An unknown error occurred. * `ER_UNKNOWN_COM_ERROR' The MySQL server doesn't implement this command (probably an old server). * `ER_ACCESS_DENIED_ERROR' The user or password was wrong. * `ER_BAD_DB_ERROR' The database didn't exist. * `ER_DBACCESS_DENIED_ERROR' The user did not have access rights to the database. * `ER_WRONG_DB_NAME' The database name was too long. * Example * if (mysql_change_user(&mysql, "user", "password", "new_database")) { fprintf(stderr, "Failed to change user. Error: %s\n", mysql_error(&mysql)); }  File: manual.info, Node: mysql-character-set-name, Next: mysql-close, Prev: mysql-change-user, Up: c-api-functions 21.9.3.4 `mysql_character_set_name()' ..................................... `const char *mysql_character_set_name(MYSQL *mysql)' * Description * Returns the default character set name for the current connection. * Return Values * The default character set name * Errors * None.  File: manual.info, Node: mysql-close, Next: mysql-commit, Prev: mysql-character-set-name, Up: c-api-functions 21.9.3.5 `mysql_close()' ........................ `void mysql_close(MYSQL *mysql)' * Description * Closes a previously opened connection. *Note `mysql_close()': mysql-close. also deallocates the connection handle pointed to by `mysql' if the handle was allocated automatically by *Note `mysql_init()': mysql-init. or *Note `mysql_connect()': mysql-connect. * Return Values * None. * Errors * None.  File: manual.info, Node: mysql-commit, Next: mysql-connect, Prev: mysql-close, Up: c-api-functions 21.9.3.6 `mysql_commit()' ......................... `my_bool mysql_commit(MYSQL *mysql)' * Description * Commits the current transaction. The action of this function is subject to the value of the `completion_type' system variable. In particular, if the value of `completion_type' is 2, the server performs a release after terminating a transaction and closes the client connection. The client program should call *Note `mysql_close()': mysql-close. to close the connection from the client side. * Return Values * Zero if successful. Nonzero if an error occurred. * Errors * None.  File: manual.info, Node: mysql-connect, Next: mysql-create-db, Prev: mysql-commit, Up: c-api-functions 21.9.3.7 `mysql_connect()' .......................... `MYSQL *mysql_connect(MYSQL *mysql, const char *host, const char *user, const char *passwd)' * Description * This function is deprecated. Use *Note `mysql_real_connect()': mysql-real-connect. instead. *Note `mysql_connect()': mysql-connect. attempts to establish a connection to a MySQL database engine running on `host'. *Note `mysql_connect()': mysql-connect. must complete successfully before you can execute any of the other API functions, with the exception of *Note `mysql_get_client_info()': mysql-get-client-info. The meanings of the parameters are the same as for the corresponding parameters for *Note `mysql_real_connect()': mysql-real-connect. with the difference that the connection parameter may be `NULL'. In this case, the C API allocates memory for the connection structure automatically and frees it when you call *Note `mysql_close()': mysql-close. The disadvantage of this approach is that you can't retrieve an error message if the connection fails. (To get error information from *Note `mysql_errno()': mysql-errno. or *Note `mysql_error()': mysql-error, you must provide a valid `MYSQL' pointer.) * Return Values * Same as for *Note `mysql_real_connect()': mysql-real-connect. * Errors * Same as for *Note `mysql_real_connect()': mysql-real-connect.  File: manual.info, Node: mysql-create-db, Next: mysql-data-seek, Prev: mysql-connect, Up: c-api-functions 21.9.3.8 `mysql_create_db()' ............................ `int mysql_create_db(MYSQL *mysql, const char *db)' * Description * Creates the database named by the `db' parameter. This function is deprecated. It is preferable to use *Note `mysql_query()': mysql-query. to issue an SQL *Note `CREATE DATABASE': create-database. statement instead. * Return Values * Zero if the database was created successfully. Nonzero if an error occurred. * Errors * * `CR_COMMANDS_OUT_OF_SYNC' Commands were executed in an improper order. * `CR_SERVER_GONE_ERROR' The MySQL server has gone away. * `CR_SERVER_LOST' The connection to the server was lost during the query. * `CR_UNKNOWN_ERROR' An unknown error occurred. * Example * if(mysql_create_db(&mysql, "my_database")) { fprintf(stderr, "Failed to create new database. Error: %s\n", mysql_error(&mysql)); }  File: manual.info, Node: mysql-data-seek, Next: mysql-debug, Prev: mysql-create-db, Up: c-api-functions 21.9.3.9 `mysql_data_seek()' ............................ `void mysql_data_seek(MYSQL_RES *result, my_ulonglong offset)' * Description * Seeks to an arbitrary row in a query result set. The `offset' value is a row number and should be in the range from `0' to *Note `mysql_num_rows(result)-1': mysql-num-rows. This function requires that the result set structure contains the entire result of the query, so *Note `mysql_data_seek()': mysql-data-seek. may be used only in conjunction with *Note `mysql_store_result()': mysql-store-result, not with *Note `mysql_use_result()': mysql-use-result. * Return Values * None. * Errors * None.  File: manual.info, Node: mysql-debug, Next: mysql-drop-db, Prev: mysql-data-seek, Up: c-api-functions 21.9.3.10 `mysql_debug()' ......................... `void mysql_debug(const char *debug)' * Description * Does a `DBUG_PUSH' with the given string. *Note `mysql_debug()': mysql-debug. uses the Fred Fish debug library. To use this function, you must compile the client library to support debugging. See MySQL Internals: Porting (http://forge.mysql.com/wiki/MySQL_Internals_Porting). * Return Values * None. * Errors * None. * Example * The call shown here causes the client library to generate a trace file in `/tmp/client.trace' on the client machine: mysql_debug("d:t:O,/tmp/client.trace");  File: manual.info, Node: mysql-drop-db, Next: mysql-dump-debug-info, Prev: mysql-debug, Up: c-api-functions 21.9.3.11 `mysql_drop_db()' ........................... `int mysql_drop_db(MYSQL *mysql, const char *db)' * Description * Drops the database named by the `db' parameter. This function is deprecated. It is preferable to use *Note `mysql_query()': mysql-query. to issue an SQL *Note `DROP DATABASE': drop-database. statement instead. * Return Values * Zero if the database was dropped successfully. Nonzero if an error occurred. * Errors * * `CR_COMMANDS_OUT_OF_SYNC' Commands were executed in an improper order. * `CR_SERVER_GONE_ERROR' The MySQL server has gone away. * `CR_SERVER_LOST' The connection to the server was lost during the query. * `CR_UNKNOWN_ERROR' An unknown error occurred. * Example * if(mysql_drop_db(&mysql, "my_database")) fprintf(stderr, "Failed to drop the database: Error: %s\n", mysql_error(&mysql));  File: manual.info, Node: mysql-dump-debug-info, Next: mysql-eof, Prev: mysql-drop-db, Up: c-api-functions 21.9.3.12 `mysql_dump_debug_info()' ................................... `int mysql_dump_debug_info(MYSQL *mysql)' * Description * Instructs the server to write some debug information to the log. For this to work, the connected user must have the `SUPER' privilege. * Return Values * Zero if the command was successful. Nonzero if an error occurred. * Errors * * `CR_COMMANDS_OUT_OF_SYNC' Commands were executed in an improper order. * `CR_SERVER_GONE_ERROR' The MySQL server has gone away. * `CR_SERVER_LOST' The connection to the server was lost during the query. * `CR_UNKNOWN_ERROR' An unknown error occurred.  File: manual.info, Node: mysql-eof, Next: mysql-errno, Prev: mysql-dump-debug-info, Up: c-api-functions 21.9.3.13 `mysql_eof()' ....................... `my_bool mysql_eof(MYSQL_RES *result)' * Description * This function is deprecated. *Note `mysql_errno()': mysql-errno. or *Note `mysql_error()': mysql-error. may be used instead. *Note `mysql_eof()': mysql-eof. determines whether the last row of a result set has been read. If you acquire a result set from a successful call to *Note `mysql_store_result()': mysql-store-result, the client receives the entire set in one operation. In this case, a `NULL' return from *Note `mysql_fetch_row()': mysql-fetch-row. always means the end of the result set has been reached and it is unnecessary to call *Note `mysql_eof()': mysql-eof. When used with *Note `mysql_store_result()': mysql-store-result, *Note `mysql_eof()': mysql-eof. always returns true. On the other hand, if you use *Note `mysql_use_result()': mysql-use-result. to initiate a result set retrieval, the rows of the set are obtained from the server one by one as you call *Note `mysql_fetch_row()': mysql-fetch-row. repeatedly. Because an error may occur on the connection during this process, a `NULL' return value from *Note `mysql_fetch_row()': mysql-fetch-row. does not necessarily mean the end of the result set was reached normally. In this case, you can use *Note `mysql_eof()': mysql-eof. to determine what happened. *Note `mysql_eof()': mysql-eof. returns a nonzero value if the end of the result set was reached and zero if an error occurred. Historically, *Note `mysql_eof()': mysql-eof. predates the standard MySQL error functions *Note `mysql_errno()': mysql-errno. and *Note `mysql_error()': mysql-error. Because those error functions provide the same information, their use is preferred over *Note `mysql_eof()': mysql-eof, which is deprecated. (In fact, they provide more information, because *Note `mysql_eof()': mysql-eof. returns only a boolean value whereas the error functions indicate a reason for the error when one occurs.) * Return Values * Zero if no error occurred. Nonzero if the end of the result set has been reached. * Errors * None. * Example * The following example shows how you might use *Note `mysql_eof()': mysql-eof.: mysql_query(&mysql,"SELECT * FROM some_table"); result = mysql_use_result(&mysql); while((row = mysql_fetch_row(result))) { // do something with data } if(!mysql_eof(result)) // mysql_fetch_row() failed due to an error { fprintf(stderr, "Error: %s\n", mysql_error(&mysql)); } However, you can achieve the same effect with the standard MySQL error functions: mysql_query(&mysql,"SELECT * FROM some_table"); result = mysql_use_result(&mysql); while((row = mysql_fetch_row(result))) { // do something with data } if(mysql_errno(&mysql)) // mysql_fetch_row() failed due to an error { fprintf(stderr, "Error: %s\n", mysql_error(&mysql)); }  File: manual.info, Node: mysql-errno, Next: mysql-error, Prev: mysql-eof, Up: c-api-functions 21.9.3.14 `mysql_errno()' ......................... `unsigned int mysql_errno(MYSQL *mysql)' * Description * For the connection specified by `mysql', *Note `mysql_errno()': mysql-errno. returns the error code for the most recently invoked API function that can succeed or fail. A return value of zero means that no error occurred. Client error message numbers are listed in the MySQL `errmsg.h' header file. Server error message numbers are listed in `mysqld_error.h'. Errors also are listed at *Note error-handling::. Note that some functions like *Note `mysql_fetch_row()': mysql-fetch-row. don't set *Note `mysql_errno()': mysql-errno. if they succeed. A rule of thumb is that all functions that have to ask the server for information reset *Note `mysql_errno()': mysql-errno. if they succeed. MySQL-specific error numbers returned by *Note `mysql_errno()': mysql-errno. differ from SQLSTATE values returned by *Note `mysql_sqlstate()': mysql-sqlstate. For example, the *Note `mysql': mysql. client program displays errors using the following format, where `1146' is the *Note `mysql_errno()': mysql-errno. value and `'42S02'' is the corresponding *Note `mysql_sqlstate()': mysql-sqlstate. value: shell> SELECT * FROM no_such_table; ERROR 1146 (42S02): Table 'test.no_such_table' doesn't exist * Return Values * An error code value for the last `mysql_XXX()' call, if it failed. zero means no error occurred. * Errors * None.  File: manual.info, Node: mysql-error, Next: mysql-escape-string, Prev: mysql-errno, Up: c-api-functions 21.9.3.15 `mysql_error()' ......................... `const char *mysql_error(MYSQL *mysql)' * Description * For the connection specified by `mysql', *Note `mysql_error()': mysql-error. returns a null-terminated string containing the error message for the most recently invoked API function that failed. If a function didn't fail, the return value of *Note `mysql_error()': mysql-error. may be the previous error or an empty string to indicate no error. A rule of thumb is that all functions that have to ask the server for information reset *Note `mysql_error()': mysql-error. if they succeed. For functions that reset *Note `mysql_error()': mysql-error, the following two tests are equivalent: if(*mysql_error(&mysql)) { // an error occurred } if(mysql_error(&mysql)[0]) { // an error occurred } The language of the client error messages may be changed by recompiling the MySQL client library. Currently, you can choose error messages in several different languages. See *Note error-message-language::. * Return Values * A null-terminated character string that describes the error. An empty string if no error occurred. * Errors * None.  File: manual.info, Node: mysql-escape-string, Next: mysql-fetch-field, Prev: mysql-error, Up: c-api-functions 21.9.3.16 `mysql_escape_string()' ................................. You should use *Note `mysql_real_escape_string()': mysql-real-escape-string. instead! This function is identical to *Note `mysql_real_escape_string()': mysql-real-escape-string. except that *Note `mysql_real_escape_string()': mysql-real-escape-string. takes a connection handler as its first argument and escapes the string according to the current character set. *Note `mysql_escape_string()': mysql-escape-string. does not take a connection argument and does not respect the current character set.  File: manual.info, Node: mysql-fetch-field, Next: mysql-fetch-field-direct, Prev: mysql-escape-string, Up: c-api-functions 21.9.3.17 `mysql_fetch_field()' ............................... `MYSQL_FIELD *mysql_fetch_field(MYSQL_RES *result)' * Description * Returns the definition of one column of a result set as a `MYSQL_FIELD' structure. Call this function repeatedly to retrieve information about all columns in the result set. *Note `mysql_fetch_field()': mysql-fetch-field. returns `NULL' when no more fields are left. *Note `mysql_fetch_field()': mysql-fetch-field. is reset to return information about the first field each time you execute a new *Note `SELECT': select. query. The field returned by *Note `mysql_fetch_field()': mysql-fetch-field. is also affected by calls to *Note `mysql_field_seek()': mysql-field-seek. If you've called *Note `mysql_query()': mysql-query. to perform a *Note `SELECT': select. on a table but have not called *Note `mysql_store_result()': mysql-store-result, MySQL returns the default blob length (8KB) if you call *Note `mysql_fetch_field()': mysql-fetch-field. to ask for the length of a *Note `BLOB': blob. field. (The 8KB size is chosen because MySQL doesn't know the maximum length for the *Note `BLOB': blob. This should be made configurable sometime.) Once you've retrieved the result set, `field->max_length' contains the length of the largest value for this column in the specific query. * Return Values * The `MYSQL_FIELD' structure for the current column. `NULL' if no columns are left. * Errors * None. * Example * MYSQL_FIELD *field; while((field = mysql_fetch_field(result))) { printf("field name %s\n", field->name); }  File: manual.info, Node: mysql-fetch-field-direct, Next: mysql-fetch-fields, Prev: mysql-fetch-field, Up: c-api-functions 21.9.3.18 `mysql_fetch_field_direct()' ...................................... `MYSQL_FIELD *mysql_fetch_field_direct(MYSQL_RES *result, unsigned int fieldnr)' * Description * Given a field number `fieldnr' for a column within a result set, returns that column's field definition as a `MYSQL_FIELD' structure. You may use this function to retrieve the definition for an arbitrary column. The value of `fieldnr' should be in the range from 0 to *Note `mysql_num_fields(result)-1': mysql-num-fields. * Return Values * The `MYSQL_FIELD' structure for the specified column. * Errors * None. * Example * unsigned int num_fields; unsigned int i; MYSQL_FIELD *field; num_fields = mysql_num_fields(result); for(i = 0; i < num_fields; i++) { field = mysql_fetch_field_direct(result, i); printf("Field %u is %s\n", i, field->name); }  File: manual.info, Node: mysql-fetch-fields, Next: mysql-fetch-lengths, Prev: mysql-fetch-field-direct, Up: c-api-functions 21.9.3.19 `mysql_fetch_fields()' ................................ `MYSQL_FIELD *mysql_fetch_fields(MYSQL_RES *result)' * Description * Returns an array of all `MYSQL_FIELD' structures for a result set. Each structure provides the field definition for one column of the result set. * Return Values * An array of `MYSQL_FIELD' structures for all columns of a result set. * Errors * None. * Example * unsigned int num_fields; unsigned int i; MYSQL_FIELD *fields; num_fields = mysql_num_fields(result); fields = mysql_fetch_fields(result); for(i = 0; i < num_fields; i++) { printf("Field %u is %s\n", i, fields[i].name); }  File: manual.info, Node: mysql-fetch-lengths, Next: mysql-fetch-row, Prev: mysql-fetch-fields, Up: c-api-functions 21.9.3.20 `mysql_fetch_lengths()' ................................. `unsigned long *mysql_fetch_lengths(MYSQL_RES *result)' * Description * Returns the lengths of the columns of the current row within a result set. If you plan to copy field values, this length information is also useful for optimization, because you can avoid calling `strlen()'. In addition, if the result set contains binary data, you *must* use this function to determine the size of the data, because `strlen()' returns incorrect results for any field containing null characters. The length for empty columns and for columns containing `NULL' values is zero. To see how to distinguish these two cases, see the description for *Note `mysql_fetch_row()': mysql-fetch-row. * Return Values * An array of unsigned long integers representing the size of each column (not including any terminating null characters). `NULL' if an error occurred. * Errors * *Note `mysql_fetch_lengths()': mysql-fetch-lengths. is valid only for the current row of the result set. It returns `NULL' if you call it before calling *Note `mysql_fetch_row()': mysql-fetch-row. or after retrieving all rows in the result. * Example * MYSQL_ROW row; unsigned long *lengths; unsigned int num_fields; unsigned int i; row = mysql_fetch_row(result); if (row) { num_fields = mysql_num_fields(result); lengths = mysql_fetch_lengths(result); for(i = 0; i < num_fields; i++) { printf("Column %u is %lu bytes in length.\n", i, lengths[i]); } }  File: manual.info, Node: mysql-fetch-row, Next: mysql-field-count, Prev: mysql-fetch-lengths, Up: c-api-functions 21.9.3.21 `mysql_fetch_row()' ............................. `MYSQL_ROW mysql_fetch_row(MYSQL_RES *result)' * Description * Retrieves the next row of a result set. When used after *Note `mysql_store_result()': mysql-store-result, *Note `mysql_fetch_row()': mysql-fetch-row. returns `NULL' when there are no more rows to retrieve. When used after *Note `mysql_use_result()': mysql-use-result, *Note `mysql_fetch_row()': mysql-fetch-row. returns `NULL' when there are no more rows to retrieve or if an error occurred. The number of values in the row is given by *Note `mysql_num_fields(result)': mysql-num-fields. If `row' holds the return value from a call to *Note `mysql_fetch_row()': mysql-fetch-row, pointers to the values are accessed as `row[0]' to `row[mysql_num_fields(result)-1]'. `NULL' values in the row are indicated by `NULL' pointers. The lengths of the field values in the row may be obtained by calling *Note `mysql_fetch_lengths()': mysql-fetch-lengths. Empty fields and fields containing `NULL' both have length 0; you can distinguish these by checking the pointer for the field value. If the pointer is `NULL', the field is `NULL'; otherwise, the field is empty. * Return Values * A `MYSQL_ROW' structure for the next row. `NULL' if there are no more rows to retrieve or if an error occurred. * Errors * Note that error is not reset between calls to *Note `mysql_fetch_row()': mysql-fetch-row. * `CR_SERVER_LOST' The connection to the server was lost during the query. * `CR_UNKNOWN_ERROR' An unknown error occurred. * Example * MYSQL_ROW row; unsigned int num_fields; unsigned int i; num_fields = mysql_num_fields(result); while ((row = mysql_fetch_row(result))) { unsigned long *lengths; lengths = mysql_fetch_lengths(result); for(i = 0; i < num_fields; i++) { printf("[%.*s] ", (int) lengths[i], row[i] ? row[i] : "NULL"); } printf("\n"); }  File: manual.info, Node: mysql-field-count, Next: mysql-field-seek, Prev: mysql-fetch-row, Up: c-api-functions 21.9.3.22 `mysql_field_count()' ............................... `unsigned int mysql_field_count(MYSQL *mysql)' * Description * Returns the number of columns for the most recent query on the connection. The normal use of this function is when *Note `mysql_store_result()': mysql-store-result. returned `NULL' (and thus you have no result set pointer). In this case, you can call *Note `mysql_field_count()': mysql-field-count. to determine whether *Note `mysql_store_result()': mysql-store-result. should have produced a nonempty result. This enables the client program to take proper action without knowing whether the query was a *Note `SELECT': select. (or *Note `SELECT': select.-like) statement. The example shown here illustrates how this may be done. See *Note null-mysql-store-result::. * Return Values * An unsigned integer representing the number of columns in a result set. * Errors * None. * Example * MYSQL_RES *result; unsigned int num_fields; unsigned int num_rows; if (mysql_query(&mysql,query_string)) { // error } else // query succeeded, process any data returned by it { result = mysql_store_result(&mysql); if (result) // there are rows { num_fields = mysql_num_fields(result); // retrieve rows, then call mysql_free_result(result) } else // mysql_store_result() returned nothing; should it have? { if(mysql_field_count(&mysql) == 0) { // query does not return data // (it was not a SELECT) num_rows = mysql_affected_rows(&mysql); } else // mysql_store_result() should have returned data { fprintf(stderr, "Error: %s\n", mysql_error(&mysql)); } } } An alternative is to replace the *Note `mysql_field_count(&mysql)': mysql-field-count. call with *Note `mysql_errno(&mysql)': mysql-errno. In this case, you are checking directly for an error from *Note `mysql_store_result()': mysql-store-result. rather than inferring from the value of *Note `mysql_field_count()': mysql-field-count. whether the statement was a *Note `SELECT': select.  File: manual.info, Node: mysql-field-seek, Next: mysql-field-tell, Prev: mysql-field-count, Up: c-api-functions 21.9.3.23 `mysql_field_seek()' .............................. `MYSQL_FIELD_OFFSET mysql_field_seek(MYSQL_RES *result, MYSQL_FIELD_OFFSET offset)' * Description * Sets the field cursor to the given offset. The next call to *Note `mysql_fetch_field()': mysql-fetch-field. retrieves the field definition of the column associated with that offset. To seek to the beginning of a row, pass an `offset' value of zero. * Return Values * The previous value of the field cursor. * Errors * None.  File: manual.info, Node: mysql-field-tell, Next: mysql-free-result, Prev: mysql-field-seek, Up: c-api-functions 21.9.3.24 `mysql_field_tell()' .............................. `MYSQL_FIELD_OFFSET mysql_field_tell(MYSQL_RES *result)' * Description * Returns the position of the field cursor used for the last *Note `mysql_fetch_field()': mysql-fetch-field. This value can be used as an argument to *Note `mysql_field_seek()': mysql-field-seek. * Return Values * The current offset of the field cursor. * Errors * None.  File: manual.info, Node: mysql-free-result, Next: mysql-get-character-set-info, Prev: mysql-field-tell, Up: c-api-functions 21.9.3.25 `mysql_free_result()' ............................... `void mysql_free_result(MYSQL_RES *result)' * Description * Frees the memory allocated for a result set by *Note `mysql_store_result()': mysql-store-result, *Note `mysql_use_result()': mysql-use-result, *Note `mysql_list_dbs()': mysql-list-dbs, and so forth. When you are done with a result set, you must free the memory it uses by calling *Note `mysql_free_result()': mysql-free-result. Do not attempt to access a result set after freeing it. * Return Values * None. * Errors * None.  File: manual.info, Node: mysql-get-character-set-info, Next: mysql-get-client-info, Prev: mysql-free-result, Up: c-api-functions 21.9.3.26 `mysql_get_character_set_info()' .......................................... `void mysql_get_character_set_info(MYSQL *mysql, MY_CHARSET_INFO *cs)' * Description * This function provides information about the default client character set. The default character set may be changed with the *Note `mysql_set_character_set()': mysql-set-character-set. function. * Example * This example shows the fields that are available in the `MY_CHARSET_INFO' structure: if (!mysql_set_character_set(&mysql, "utf8")) { MY_CHARSET_INFO cs; mysql_get_character_set_info(&mysql, &cs); printf("character set information:\n"); printf("character set+collation number: %d\n", cs.number); printf("character set name: %s\n", cs.name); printf("collation name: %s\n", cs.csname); printf("comment: %s\n", cs.comment); printf("directory: %s\n", cs.dir); printf("multi byte character min. length: %d\n", cs.mbminlen); printf("multi byte character max. length: %d\n", cs.mbmaxlen); }  File: manual.info, Node: mysql-get-client-info, Next: mysql-get-client-version, Prev: mysql-get-character-set-info, Up: c-api-functions 21.9.3.27 `mysql_get_client_info()' ................................... `const char *mysql_get_client_info(void)' * Description * Returns a string that represents the client library version. * Return Values * A character string that represents the MySQL client library version. * Errors * None.  File: manual.info, Node: mysql-get-client-version, Next: mysql-get-host-info, Prev: mysql-get-client-info, Up: c-api-functions 21.9.3.28 `mysql_get_client_version()' ...................................... `unsigned long mysql_get_client_version(void)' * Description * Returns an integer that represents the client library version. The value has the format `XYYZZ' where `X' is the major version, `YY' is the release level, and `ZZ' is the version number within the release level. For example, a value of `40102' represents a client library version of `4.1.2'. * Return Values * An integer that represents the MySQL client library version. * Errors * None.  File: manual.info, Node: mysql-get-host-info, Next: mysql-get-proto-info, Prev: mysql-get-client-version, Up: c-api-functions 21.9.3.29 `mysql_get_host_info()' ................................. `const char *mysql_get_host_info(MYSQL *mysql)' * Description * Returns a string describing the type of connection in use, including the server host name. * Return Values * A character string representing the server host name and the connection type. * Errors * None.  File: manual.info, Node: mysql-get-proto-info, Next: mysql-get-server-info, Prev: mysql-get-host-info, Up: c-api-functions 21.9.3.30 `mysql_get_proto_info()' .................................. `unsigned int mysql_get_proto_info(MYSQL *mysql)' * Description * Returns the protocol version used by current connection. * Return Values * An unsigned integer representing the protocol version used by the current connection. * Errors * None.  File: manual.info, Node: mysql-get-server-info, Next: mysql-get-server-version, Prev: mysql-get-proto-info, Up: c-api-functions 21.9.3.31 `mysql_get_server_info()' ................................... `const char *mysql_get_server_info(MYSQL *mysql)' * Description * Returns a string that represents the server version number. * Return Values * A character string that represents the server version number. * Errors * None.  File: manual.info, Node: mysql-get-server-version, Next: mysql-get-ssl-cipher, Prev: mysql-get-server-info, Up: c-api-functions 21.9.3.32 `mysql_get_server_version()' ...................................... `unsigned long mysql_get_server_version(MYSQL *mysql)' * Description * Returns the version number of the server as an integer. * Return Values * A number that represents the MySQL server version in this format: major_version*10000 + minor_version *100 + sub_version For example, 5.1.5 is returned as 50105. This function is useful in client programs for quickly determining whether some version-specific server capability exists. * Errors * None.  File: manual.info, Node: mysql-get-ssl-cipher, Next: mysql-hex-string, Prev: mysql-get-server-version, Up: c-api-functions 21.9.3.33 `mysql_get_ssl_cipher()' .................................. `const char *mysql_get_ssl_cipher(MYSQL *mysql)' * Description * *Note `mysql_get_ssl_cipher()': mysql-get-ssl-cipher. returns the SSL cipher used for the given connection to the server. `mysql' is the connection handler returned from *Note `mysql_init()': mysql-init. This function was added in MySQL 5.1.11. * Return Values * A string naming the SSL cipher used for the connection, or `NULL' if no cipher is being used.  File: manual.info, Node: mysql-hex-string, Next: mysql-info, Prev: mysql-get-ssl-cipher, Up: c-api-functions 21.9.3.34 `mysql_hex_string()' .............................. `unsigned long mysql_hex_string(char *to, const char *from, unsigned long length)' * Description * This function is used to create a legal SQL string that you can use in an SQL statement. See *Note string-syntax::. The string in `from' is encoded to hexadecimal format, with each character encoded as two hexadecimal digits. The result is placed in `to' and a terminating null byte is appended. The string pointed to by `from' must be `length' bytes long. You must allocate the `to' buffer to be at least `length*2+1' bytes long. When *Note `mysql_hex_string()': mysql-hex-string. returns, the contents of `to' is a null-terminated string. The return value is the length of the encoded string, not including the terminating null character. The return value can be placed into an SQL statement using either `0xVALUE' or `X'VALUE'' format. However, the return value does not include the `0x' or `X'...''. The caller must supply whichever of those is desired. * Example * char query[1000],*end; end = strmov(query,"INSERT INTO test_table values("); end = strmov(end,"0x"); end += mysql_hex_string(end,"What is this",12); end = strmov(end,",0x"); end += mysql_hex_string(end,"binary data: \0\r\n",16); *end++ = ')'; if (mysql_real_query(&mysql,query,(unsigned int) (end - query))) { fprintf(stderr, "Failed to insert row, Error: %s\n", mysql_error(&mysql)); } The `strmov()' function used in the example is included in the `mysqlclient' library and works like `strcpy()' but returns a pointer to the terminating null of the first parameter. * Return Values * The length of the value placed into `to', not including the terminating null character. * Errors * None.  File: manual.info, Node: mysql-info, Next: mysql-init, Prev: mysql-hex-string, Up: c-api-functions 21.9.3.35 `mysql_info()' ........................ `const char *mysql_info(MYSQL *mysql)' * Description * Retrieves a string providing information about the most recently executed statement, but only for the statements listed here. For other statements, *Note `mysql_info()': mysql-info. returns `NULL'. The format of the string varies depending on the type of statement, as described here. The numbers are illustrative only; the string contains values appropriate for the statement. * *Note `INSERT INTO ... SELECT ...': insert-select. String format: `Records: 100 Duplicates: 0 Warnings: 0' * `INSERT INTO ... VALUES (...),(...),(...)...' String format: `Records: 3 Duplicates: 0 Warnings: 0' * *Note `LOAD DATA INFILE ...': load-data. String format: `Records: 1 Deleted: 0 Skipped: 0 Warnings: 0' * *Note `ALTER TABLE': alter-table. String format: `Records: 3 Duplicates: 0 Warnings: 0' * *Note `UPDATE': update. String format: `Rows matched: 40 Changed: 40 Warnings: 0' Note that *Note `mysql_info()': mysql-info. returns a non-`NULL' value for *Note `INSERT ... VALUES': insert. only for the multiple-row form of the statement (that is, only if multiple value lists are specified). * Return Values * A character string representing additional information about the most recently executed statement. `NULL' if no information is available for the statement. * Errors * None.  File: manual.info, Node: mysql-init, Next: mysql-insert-id, Prev: mysql-info, Up: c-api-functions 21.9.3.36 `mysql_init()' ........................ `MYSQL *mysql_init(MYSQL *mysql)' * Description * Allocates or initializes a `MYSQL' object suitable for *Note `mysql_real_connect()': mysql-real-connect. If `mysql' is a `NULL' pointer, the function allocates, initializes, and returns a new object. Otherwise, the object is initialized and the address of the object is returned. If *Note `mysql_init()': mysql-init. allocates a new object, it is freed when *Note `mysql_close()': mysql-close. is called to close the connection. * Return Values * An initialized `MYSQL*' handle. `NULL' if there was insufficient memory to allocate a new object. * Errors * In case of insufficient memory, `NULL' is returned.  File: manual.info, Node: mysql-insert-id, Next: mysql-kill, Prev: mysql-init, Up: c-api-functions 21.9.3.37 `mysql_insert_id()' ............................. `my_ulonglong mysql_insert_id(MYSQL *mysql)' * Description * Returns the value generated for an `AUTO_INCREMENT' column by the previous *Note `INSERT': insert. or *Note `UPDATE': update. statement. Use this function after you have performed an *Note `INSERT': insert. statement into a table that contains an `AUTO_INCREMENT' field, or have used *Note `INSERT': insert. or *Note `UPDATE': update. to set a column value with `LAST_INSERT_ID(EXPR)'. The return value of *Note `mysql_insert_id()': mysql-insert-id. is always zero unless explicitly updated under one of the following conditions: * *Note `INSERT': insert. statements that store a value into an `AUTO_INCREMENT' column. This is true whether the value is automatically generated by storing the special values `NULL' or `0' into the column, or is an explicit nonspecial value. * In the case of a multiple-row *Note `INSERT': insert. statement, the return value of *Note `mysql_insert_id()': mysql-insert-id. depends on the MySQL server version. In MySQL 5.1.12 and later, *Note `mysql_insert_id()': mysql-insert-id. returns the _first_ automatically generated `AUTO_INCREMENT' value that was _successfully_ inserted. In MySQL 5.1.11 and earlier, *Note `mysql_insert_id()': mysql-insert-id. returns the _first_ automatically generated `AUTO_INCREMENT' value, regardless of whether insertion of that value was successful. If no rows are successfully inserted, *Note `mysql_insert_id()': mysql-insert-id. returns 0. * Starting in MySQL 5.1.12, if an *Note `INSERT ... SELECT': insert-select. statement is executed, and no automatically generated value is successfully inserted, *Note `mysql_insert_id()': mysql-insert-id. returns the ID of the last inserted row. * Starting in MySQL 5.1.12, if an *Note `INSERT ... SELECT': insert-select. statement uses `LAST_INSERT_ID(EXPR)', *Note `mysql_insert_id()': mysql-insert-id. returns EXPR. * *Note `INSERT': insert. statements that generate an `AUTO_INCREMENT' value by inserting `LAST_INSERT_ID(EXPR)' into any column or by updating any column to `LAST_INSERT_ID(EXPR)'. * If the previous statement returned an error, the value of *Note `mysql_insert_id()': mysql-insert-id. is undefined. For 5.1.12 and later, the return value of *Note `mysql_insert_id()': mysql-insert-id. can be simplified to the following sequence: 1. If there is an `AUTO_INCREMENT' column, and an automatically generated value was successfully inserted, return the first such value. 2. If `LAST_INSERT_ID(EXPR)' occurred in the statement, return EXPR, even if there was an `AUTO_INCREMENT' column in the affected table. 3. The return value varies depending on the statement used. When called after an *Note `INSERT': insert. statement: * If there is an `AUTO_INCREMENT' column in the table, and there were some explicit values for this column that were successfully inserted into the table, return the last of the explicit values. When called after an *Note `INSERT ... ON DUPLICATE KEY UPDATE': insert-on-duplicate. statement: * If there is an `AUTO_INCREMENT' column in the table and there were some explicit successfully inserted values, or some updated rows, return the last of the inserted or updated values. *Note `mysql_insert_id()': mysql-insert-id. returns `0' if the previous statement does not use an `AUTO_INCREMENT' value. If you need to save the value for later, be sure to call *Note `mysql_insert_id()': mysql-insert-id. immediately after the statement that generates the value. The value of *Note `mysql_insert_id()': mysql-insert-id. is affected only by statements issued within the current client connection. It is not affected by statements issued by other clients. The `LAST_INSERT_ID()' SQL function returns the value of the first automatically generated value that was successfully inserted (starting from 5.1.12) or the first automatically generated value if any rows were successfully inserted (before 5.1.12). `LAST_INSERT_ID()' is not reset between statements because the value of that function is maintained in the server. Another difference from *Note `mysql_insert_id()': mysql-insert-id. is that `LAST_INSERT_ID()' is not updated if you set an `AUTO_INCREMENT' column to a specific nonspecial value. See *Note information-functions::. *Note `mysql_insert_id()': mysql-insert-id. returns `0' following a *Note `CALL': call. statement for a stored procedure that generates an `AUTO_INCREMENT' value because in this case *Note `mysql_insert_id()': mysql-insert-id. applies to *Note `CALL': call. and not the statement within the procedure. Within the procedure, you can use `LAST_INSERT_ID()' at the SQL level to obtain the `AUTO_INCREMENT' value. The reason for the differences between `LAST_INSERT_ID()' and *Note `mysql_insert_id()': mysql-insert-id. is that `LAST_INSERT_ID()' is made easy to use in scripts while *Note `mysql_insert_id()': mysql-insert-id. tries to provide more exact information about what happens to the `AUTO_INCREMENT' column. * Return Values * Described in the preceding discussion. * Errors * None.  File: manual.info, Node: mysql-kill, Next: mysql-library-end, Prev: mysql-insert-id, Up: c-api-functions 21.9.3.38 `mysql_kill()' ........................ `int mysql_kill(MYSQL *mysql, unsigned long pid)' * Description * Asks the server to kill the thread specified by `pid'. This function is deprecated. It is preferable to use *Note `mysql_query()': mysql-query. to issue an SQL *Note `KILL': kill. statement instead. * Return Values * Zero for success. Nonzero if an error occurred. * Errors * * `CR_COMMANDS_OUT_OF_SYNC' Commands were executed in an improper order. * `CR_SERVER_GONE_ERROR' The MySQL server has gone away. * `CR_SERVER_LOST' The connection to the server was lost during the query. * `CR_UNKNOWN_ERROR' An unknown error occurred.  File: manual.info, Node: mysql-library-end, Next: mysql-library-init, Prev: mysql-kill, Up: c-api-functions 21.9.3.39 `mysql_library_end()' ............................... `void mysql_library_end(void)' * Description * This function finalizes the MySQL library. You should call it when you are done using the library (for example, after disconnecting from the server). The action taken by the call depends on whether your application is linked to the MySQL client library or the MySQL embedded server library. For a client program linked against the `libmysqlclient' library by using the `-lmysqlclient' flag, *Note `mysql_library_end()': mysql-library-end. performs some memory management to clean up. For an embedded server application linked against the `libmysqld' library by using the `-lmysqld' flag, *Note `mysql_library_end()': mysql-library-end. shuts down the embedded server and then cleans up. For usage information, see *Note c-api-function-overview::, and *Note mysql-library-init::.  File: manual.info, Node: mysql-library-init, Next: mysql-list-dbs, Prev: mysql-library-end, Up: c-api-functions 21.9.3.40 `mysql_library_init()' ................................ `int mysql_library_init(int argc, char **argv, char **groups)' * Description * This function should be called to initialize the MySQL library before you call any other MySQL function, whether your application is a regular client program or uses the embedded server. If the application uses the embedded server, this call starts the server and initializes any subsystems (`mysys', `InnoDB', and so forth) that the server uses. After your application is done using the MySQL library, call *Note `mysql_library_end()': mysql-library-end. to clean up. See *Note mysql-library-end::. The choice of whether the application operates as a regular client or uses the embedded server depends on whether you use the `libmysqlclient' or `libmysqld' library at link time to produce the final executable. For additional information, see *Note c-api-function-overview::. In a nonmulti-threaded environment, the call to *Note `mysql_library_init()': mysql-library-init. may be omitted, because *Note `mysql_init()': mysql-init. will invoke it automatically as necessary. However, *Note `mysql_library_init()': mysql-library-init. is not thread-safe in a multi-threaded environment, and thus neither is *Note `mysql_init()': mysql-init, which calls *Note `mysql_library_init()': mysql-library-init. You must either call *Note `mysql_library_init()': mysql-library-init. prior to spawning any threads, or else use a mutex to protect the call, whether you invoke *Note `mysql_library_init()': mysql-library-init. or indirectly through *Note `mysql_init()': mysql-init. This should be done prior to any other client library call. The `argc' and `argv' arguments are analogous to the arguments to `main()', and enable passing of options to the embedded server. For convenience, `argc' may be `0' (zero) if there are no command-line arguments for the server. This is the usual case for applications intended for use only as regular (nonembedded) clients, and the call typically is written as *Note `mysql_library_init(0, NULL, NULL)': mysql-library-init. #include #include int main(void) { if (mysql_library_init(0, NULL, NULL)) { fprintf(stderr, "could not initialize MySQL library\n"); exit(1); } /* Use any MySQL API functions here */ mysql_library_end(); return EXIT_SUCCESS; } When arguments are to be passed (`argc' is greater than `0'), the first element of `argv' is ignored (it typically contains the program name). *Note `mysql_library_init()': mysql-library-init. makes a copy of the arguments so it is safe to destroy `argv' or `groups' after the call. For embedded applications, if you want to connect to an external server without starting the embedded server, you have to specify a negative value for `argc'. The `groups' argument should be an array of strings that indicate the groups in option files from which options should be read. See *Note option-files::. The final entry in the array should be `NULL'. For convenience, if the `groups' argument itself is `NULL', the `[server]' and `[embedded]' groups are used by default. #include #include static char *server_args[] = { "this_program", /* this string is not used */ "--datadir=.", "--key_buffer_size=32M" }; static char *server_groups[] = { "embedded", "server", "this_program_SERVER", (char *)NULL }; int main(void) { if (mysql_library_init(sizeof(server_args) / sizeof(char *), server_args, server_groups)) { fprintf(stderr, "could not initialize MySQL library\n"); exit(1); } /* Use any MySQL API functions here */ mysql_library_end(); return EXIT_SUCCESS; } * Return Values * Zero if successful. Nonzero if an error occurred.  File: manual.info, Node: mysql-list-dbs, Next: mysql-list-fields, Prev: mysql-library-init, Up: c-api-functions 21.9.3.41 `mysql_list_dbs()' ............................ `MYSQL_RES *mysql_list_dbs(MYSQL *mysql, const char *wild)' * Description * Returns a result set consisting of database names on the server that match the simple regular expression specified by the `wild' parameter. `wild' may contain the wildcard characters ``%'' or ``_'', or may be a `NULL' pointer to match all databases. Calling *Note `mysql_list_dbs()': mysql-list-dbs. is similar to executing the query `SHOW DATABASES [LIKE WILD]'. You must free the result set with *Note `mysql_free_result()': mysql-free-result. * Return Values * A `MYSQL_RES' result set for success. `NULL' if an error occurred. * Errors * * `CR_COMMANDS_OUT_OF_SYNC' Commands were executed in an improper order. * `CR_OUT_OF_MEMORY' Out of memory. * `CR_SERVER_GONE_ERROR' The MySQL server has gone away. * `CR_SERVER_LOST' The connection to the server was lost during the query. * `CR_UNKNOWN_ERROR' An unknown error occurred.  File: manual.info, Node: mysql-list-fields, Next: mysql-list-processes, Prev: mysql-list-dbs, Up: c-api-functions 21.9.3.42 `mysql_list_fields()' ............................... `MYSQL_RES *mysql_list_fields(MYSQL *mysql, const char *table, const char *wild)' * Description * Returns a result set consisting of field names in the given table that match the simple regular expression specified by the `wild' parameter. `wild' may contain the wildcard characters ``%'' or ``_'', or may be a `NULL' pointer to match all fields. Calling *Note `mysql_list_fields()': mysql-list-fields. is similar to executing the query `SHOW COLUMNS FROM TBL_NAME [LIKE WILD]'. It is preferable to use `SHOW COLUMNS FROM TBL_NAME' instead of *Note `mysql_list_fields()': mysql-list-fields. You must free the result set with *Note `mysql_free_result()': mysql-free-result. * Return Values * A `MYSQL_RES' result set for success. `NULL' if an error occurred. * Errors * * `CR_COMMANDS_OUT_OF_SYNC' Commands were executed in an improper order. * `CR_SERVER_GONE_ERROR' The MySQL server has gone away. * `CR_SERVER_LOST' The connection to the server was lost during the query. * `CR_UNKNOWN_ERROR' An unknown error occurred.  File: manual.info, Node: mysql-list-processes, Next: mysql-list-tables, Prev: mysql-list-fields, Up: c-api-functions 21.9.3.43 `mysql_list_processes()' .................................. `MYSQL_RES *mysql_list_processes(MYSQL *mysql)' * Description * Returns a result set describing the current server threads. This is the same kind of information as that reported by *Note `mysqladmin processlist': mysqladmin. or a *Note `SHOW PROCESSLIST': show-processlist. query. You must free the result set with *Note `mysql_free_result()': mysql-free-result. * Return Values * A `MYSQL_RES' result set for success. `NULL' if an error occurred. * Errors * * `CR_COMMANDS_OUT_OF_SYNC' Commands were executed in an improper order. * `CR_SERVER_GONE_ERROR' The MySQL server has gone away. * `CR_SERVER_LOST' The connection to the server was lost during the query. * `CR_UNKNOWN_ERROR' An unknown error occurred.  File: manual.info, Node: mysql-list-tables, Next: mysql-more-results, Prev: mysql-list-processes, Up: c-api-functions 21.9.3.44 `mysql_list_tables()' ............................... `MYSQL_RES *mysql_list_tables(MYSQL *mysql, const char *wild)' * Description * Returns a result set consisting of table names in the current database that match the simple regular expression specified by the `wild' parameter. `wild' may contain the wildcard characters ``%'' or ``_'', or may be a `NULL' pointer to match all tables. Calling *Note `mysql_list_tables()': mysql-list-tables. is similar to executing the query `SHOW TABLES [LIKE WILD]'. You must free the result set with *Note `mysql_free_result()': mysql-free-result. * Return Values * A `MYSQL_RES' result set for success. `NULL' if an error occurred. * Errors * * `CR_COMMANDS_OUT_OF_SYNC' Commands were executed in an improper order. * `CR_SERVER_GONE_ERROR' The MySQL server has gone away. * `CR_SERVER_LOST' The connection to the server was lost during the query. * `CR_UNKNOWN_ERROR' An unknown error occurred.  File: manual.info, Node: mysql-more-results, Next: mysql-next-result, Prev: mysql-list-tables, Up: c-api-functions 21.9.3.45 `mysql_more_results()' ................................ `my_bool mysql_more_results(MYSQL *mysql)' * Description * This function is used when you execute multiple statements specified as a single statement string, or when you execute *Note `CALL': call. statements, which can return multiple result sets. *Note `mysql_more_results()': mysql-more-results. true if more results exist from the currently executed statement, in which case the application must call *Note `mysql_next_result()': mysql-next-result. to fetch the results. * Return Values * `TRUE' (1) if more results exist. `FALSE' (0) if no more results exist. In most cases, you can call *Note `mysql_next_result()': mysql-next-result. instead to test whether more results exist and initiate retrieval if so. See *Note c-api-multiple-queries::, and *Note mysql-next-result::. * Errors * None.  File: manual.info, Node: mysql-next-result, Next: mysql-num-fields, Prev: mysql-more-results, Up: c-api-functions 21.9.3.46 `mysql_next_result()' ............................... `int mysql_next_result(MYSQL *mysql)' * Description * This function is used when you execute multiple statements specified as a single statement string, or when you use *Note `CALL': call. statements to execute stored procedures, which can return multiple result sets. *Note `mysql_next_result()': mysql-next-result. reads the next statement result and returns a status to indicate whether more results exist. If *Note `mysql_next_result()': mysql-next-result. returns an error, there are no more results. Before each call to *Note `mysql_next_result()': mysql-next-result, you must call *Note `mysql_free_result()': mysql-free-result. for the current statement if it is a statement that returned a result set (rather than just a result status). After calling *Note `mysql_next_result()': mysql-next-result. the state of the connection is as if you had called *Note `mysql_real_query()': mysql-real-query. or *Note `mysql_query()': mysql-query. for the next statement. This means that you can call *Note `mysql_store_result()': mysql-store-result, *Note `mysql_warning_count()': mysql-warning-count, *Note `mysql_affected_rows()': mysql-affected-rows, and so forth. If your program uses *Note `CALL': call. statements to execute stored procedures, the `CLIENT_MULTI_RESULTS' flag must be enabled. This is because each *Note `CALL': call. returns a result to indicate the call status, in addition to any result sets that might be returned by statements executed within the procedure. Because *Note `CALL': call. can return multiple results, you should process them using a loop that calls *Note `mysql_next_result()': mysql-next-result. to determine whether there are more results. `CLIENT_MULTI_RESULTS' can be enabled when you call *Note `mysql_real_connect()': mysql-real-connect, either explicitly by passing the `CLIENT_MULTI_RESULTS' flag itself, or implicitly by passing `CLIENT_MULTI_STATEMENTS' (which also enables `CLIENT_MULTI_RESULTS'). It is also possible to test whether there are more results by calling *Note `mysql_more_results()': mysql-more-results. However, this function does not change the connection state, so if it returns true, you must still call *Note `mysql_next_result()': mysql-next-result. to advance to the next result. For an example that shows how to use *Note `mysql_next_result()': mysql-next-result, see *Note c-api-multiple-queries::. * Return Values * Return Value Description 0 Successful and there are more results -1 Successful and there are no more results >0 An error occurred * Errors * * `CR_COMMANDS_OUT_OF_SYNC' Commands were executed in an improper order. For example, if you didn't call *Note `mysql_use_result()': mysql-use-result. for a previous result set. * `CR_SERVER_GONE_ERROR' The MySQL server has gone away. * `CR_SERVER_LOST' The connection to the server was lost during the query. * `CR_UNKNOWN_ERROR' An unknown error occurred.  File: manual.info, Node: mysql-num-fields, Next: mysql-num-rows, Prev: mysql-next-result, Up: c-api-functions 21.9.3.47 `mysql_num_fields()' .............................. `unsigned int mysql_num_fields(MYSQL_RES *result)' To pass a `MYSQL*' argument instead, use `unsigned int mysql_field_count(MYSQL *mysql)'. * Description * Returns the number of columns in a result set. Note that you can get the number of columns either from a pointer to a result set or to a connection handle. You would use the connection handle if *Note `mysql_store_result()': mysql-store-result. or *Note `mysql_use_result()': mysql-use-result. returned `NULL' (and thus you have no result set pointer). In this case, you can call *Note `mysql_field_count()': mysql-field-count. to determine whether *Note `mysql_store_result()': mysql-store-result. should have produced a nonempty result. This enables the client program to take proper action without knowing whether the query was a *Note `SELECT': select. (or *Note `SELECT': select.-like) statement. The example shown here illustrates how this may be done. See *Note null-mysql-store-result::. * Return Values * An unsigned integer representing the number of columns in a result set. * Errors * None. * Example * MYSQL_RES *result; unsigned int num_fields; unsigned int num_rows; if (mysql_query(&mysql,query_string)) { // error } else // query succeeded, process any data returned by it { result = mysql_store_result(&mysql); if (result) // there are rows { num_fields = mysql_num_fields(result); // retrieve rows, then call mysql_free_result(result) } else // mysql_store_result() returned nothing; should it have? { if (mysql_errno(&mysql)) { fprintf(stderr, "Error: %s\n", mysql_error(&mysql)); } else if (mysql_field_count(&mysql) == 0) { // query does not return data // (it was not a SELECT) num_rows = mysql_affected_rows(&mysql); } } } An alternative (if you know that your query should have returned a result set) is to replace the *Note `mysql_errno(&mysql)': mysql-errno. call with a check whether *Note `mysql_field_count(&mysql)': mysql-field-count. returns 0. This happens only if something went wrong.  File: manual.info, Node: mysql-num-rows, Next: mysql-options, Prev: mysql-num-fields, Up: c-api-functions 21.9.3.48 `mysql_num_rows()' ............................ `my_ulonglong mysql_num_rows(MYSQL_RES *result)' * Description * Returns the number of rows in the result set. The use of *Note `mysql_num_rows()': mysql-num-rows. depends on whether you use *Note `mysql_store_result()': mysql-store-result. or *Note `mysql_use_result()': mysql-use-result. to return the result set. If you use *Note `mysql_store_result()': mysql-store-result, *Note `mysql_num_rows()': mysql-num-rows. may be called immediately. If you use *Note `mysql_use_result()': mysql-use-result, *Note `mysql_num_rows()': mysql-num-rows. does not return the correct value until all the rows in the result set have been retrieved. *Note `mysql_num_rows()': mysql-num-rows. is intended for use with statements that return a result set, such as *Note `SELECT': select. For statements such as *Note `INSERT': insert, *Note `UPDATE': update, or *Note `DELETE': delete, the number of affected rows can be obtained with *Note `mysql_affected_rows()': mysql-affected-rows. * Return Values * The number of rows in the result set. * Errors * None.  File: manual.info, Node: mysql-options, Next: mysql-ping, Prev: mysql-num-rows, Up: c-api-functions 21.9.3.49 `mysql_options()' ........................... `int mysql_options(MYSQL *mysql, enum mysql_option option, const void *arg)' * Description * Can be used to set extra connect options and affect behavior for a connection. This function may be called multiple times to set several options. *Note `mysql_options()': mysql-options. should be called after *Note `mysql_init()': mysql-init. and before *Note `mysql_connect()': mysql-connect. or *Note `mysql_real_connect()': mysql-real-connect. The `option' argument is the option that you want to set; the `arg' argument is the value for the option. If the option is an integer, `arg' should point to the value of the integer. The following list describes the possible options, their effect, and how `arg' is used for each option. Several of the options apply only when the application is linked against the `libmysqld' embedded server library and are unused for applications linked against the `libmysql' client library. For option descriptions that indicate `arg' is unused, its value is irrelevant; it is conventional to pass 0. * `MYSQL_INIT_COMMAND' (argument type: `char *') SQL statement to execute when connecting to the MySQL server. Automatically re-executed if reconnection occurs. * `MYSQL_OPT_COMPRESS' (argument: not used) Use the compressed client/server protocol. * `MYSQL_OPT_CONNECT_TIMEOUT' (argument type: `unsigned int *') Connect timeout in seconds. * `MYSQL_OPT_GUESS_CONNECTION' (argument: not used) For an application linked against the `libmysqld' embedded server library, this enables the library to guess whether to use the embedded server or a remote server. `Guess' means that if the host name is set and is not `localhost', it uses a remote server. This behavior is the default. `MYSQL_OPT_USE_EMBEDDED_CONNECTION' and `MYSQL_OPT_USE_REMOTE_CONNECTION' can be used to override it. This option is ignored for applications linked against the `libmysqlclient' client library. * `MYSQL_OPT_LOCAL_INFILE' (argument type: optional pointer to `unsigned int') If no pointer is given or if pointer points to an `unsigned int' that has a nonzero value, the `LOAD LOCAL INFILE' statement is enabled. * `MYSQL_OPT_NAMED_PIPE' (argument: not used) Use named pipes to connect to a MySQL server on Windows, if the server permits named-pipe connections. * `MYSQL_OPT_PROTOCOL' (argument type: `unsigned int *') Type of protocol to use. Should be one of the enum values of `mysql_protocol_type' defined in `mysql.h'. * `MYSQL_OPT_READ_TIMEOUT' (argument type: `unsigned int *') The timeout in seconds for attempts to read from the server. Each attempt uses this timeout value and there are retries if necessary, so the total effective timeout value is three times the option value. You can set the value so that a lost connection can be detected earlier than the TCP/IP `Close_Wait_Timeout' value of 10 minutes. Before MySQL 5.1.41, this option applies only to TCP/IP connections and, prior to MySQL 5.1.12, only for Windows. * `MYSQL_OPT_RECONNECT' (argument type: `my_bool *') Enable or disable automatic reconnection to the server if the connection is found to have been lost. Reconnect is off by default; this option provides a way to set reconnection behavior explicitly. Note: *Note `mysql_real_connect()': mysql-real-connect. incorrectly reset the `MYSQL_OPT_RECONNECT' option to its default value before MySQL 5.1.6. Therefore, prior to that version, if you want reconnect to be enabled for each connection, you must call *Note `mysql_options()': mysql-options. with the `MYSQL_OPT_RECONNECT' option after each call to *Note `mysql_real_connect()': mysql-real-connect. This is not necessary as of 5.1.6: Call *Note `mysql_options()': mysql-options. only before *Note `mysql_real_connect()': mysql-real-connect. as usual. * `MYSQL_SET_CLIENT_IP' (argument type: `char *') For an application linked against the `libmysqld' embedded server library (when `libmysqld' is compiled with authentication support), this means that the user is considered to have connected from the specified IP address (specified as a string) for authentication purposes. This option is ignored for applications linked against the `libmysqlclient' client library. * `MYSQL_OPT_SSL_VERIFY_SERVER_CERT' (argument type: `my_bool *') Enable or disable verification of the server's Common Name value in its certificate against the host name used when connecting to the server. The connection is rejected if there is a mismatch. This feature can be used to prevent man-in-the-middle attacks. Verification is disabled by default. Added in MySQL 5.1.11. * `MYSQL_OPT_USE_EMBEDDED_CONNECTION' (argument: not used) For an application linked against the `libmysqld' embedded server library, this forces the use of the embedded server for the connection. This option is ignored for applications linked against the `libmysqlclient' client library. * `MYSQL_OPT_USE_REMOTE_CONNECTION' (argument: not used) For an application linked against the `libmysqld' embedded server library, this forces the use of a remote server for the connection. This option is ignored for applications linked against the `libmysqlclient' client library. * `MYSQL_OPT_USE_RESULT' (argument: not used) This option is unused. * `MYSQL_OPT_WRITE_TIMEOUT' (argument type: `unsigned int *') The timeout in seconds for attempts to write to the server. Each attempt uses this timeout value and there are `net_retry_count' retries if necessary, so the total effective timeout value is `net_retry_count' times the option value. Before MySQL 5.1.41, this option applies only to TCP/IP connections and, prior to MySQL 5.1.12, only for Windows. * `MYSQL_READ_DEFAULT_FILE' (argument type: `char *') Read options from the named option file instead of from `my.cnf'. * `MYSQL_READ_DEFAULT_GROUP' (argument type: `char *') Read options from the named group from `my.cnf' or the file specified with `MYSQL_READ_DEFAULT_FILE'. * `MYSQL_REPORT_DATA_TRUNCATION' (argument type: `my_bool *') Enable or disable reporting of data truncation errors for prepared statements using the `error' member of `MYSQL_BIND' structures. (Default: enabled.) * `MYSQL_SECURE_AUTH' (argument type: `my_bool *') Whether to connect to a server that does not support the password hashing used in MySQL 4.1.1 and later. * `MYSQL_SET_CHARSET_DIR' (argument type: `char *') The path name to the directory that contains character set definition files. * `MYSQL_SET_CHARSET_NAME' (argument type: `char *') The name of the character set to use as the default character set. * `MYSQL_SHARED_MEMORY_BASE_NAME' (argument type: `char *') The name of the shared-memory object for communication to the server on Windows, if the server supports shared-memory connections. Should have the same value as the `--shared-memory-base-name' option used for the *Note `mysqld': mysqld. server you want to connect to. The `client' group is always read if you use `MYSQL_READ_DEFAULT_FILE' or `MYSQL_READ_DEFAULT_GROUP'. The specified group in the option file may contain the following options. Option Description `character-sets-dir=PATH' The directory where character sets are installed. `compress' Use the compressed client/server protocol. `connect-timeout=SECONDS' Connect timeout in seconds. On Linux this timeout is also used for waiting for the first answer from the server. `database=DB_NAME' Connect to this database if no database was specified in the connect command. `debug' Debug options. `default-character-set=CHARSET_NAME'The default character set to use. `disable-local-infile' Disable use of *Note `LOAD DATA LOCAL': load-data. `host=HOST_NAME' Default host name. `init-command=STMT' Statement to execute when connecting to MySQL server. Automatically re-executed if reconnection occurs. `interactive-timeout=SECONDS'Same as specifying `CLIENT_INTERACTIVE' to *Note `mysql_real_connect()': mysql-real-connect. See *Note mysql-real-connect::. `local-infile[={0|1}]' If no argument or nonzero argument, enable use of *Note `LOAD DATA LOCAL': load-data.; otherwise disable. `max_allowed_packet=BYTES'Maximum size of packet that client can read from server. `multi-queries', Enable multiple result sets from `multi-results' multiple-statement executions or stored procedures. `multi-statements' Enable the client to send multiple statements in a single string (separated by ``;''). `password=PASSWORD' Default password. `pipe' Use named pipes to connect to a MySQL server on Windows. `port=PORT_NUM' Default port number. `protocol={TCP|SOCKET|PIPE|MEMORY}'The protocol to use when connecting to the server. `return-found-rows' Tell *Note `mysql_info()': mysql-info. to return found rows instead of updated rows when using *Note `UPDATE': update. `shared-memory-base-name=NAME'Shared-memory name to use to connect to server. `socket=PATH' Default socket file. `ssl-ca=FILE_NAME' Certificate Authority file. `ssl-capath=PATH' Certificate Authority directory. `ssl-cert=FILE_NAME' Certificate file. `ssl-cipher=CIPHER_LIST' Permissible SSL ciphers. `ssl-key=FILE_NAME' Key file. `timeout=SECONDS' Like `connect-timeout'. `user' Default user. `timeout' has been replaced by `connect-timeout', but `timeout' is still supported in MySQL 5.1 for backward compatibility. For more information about option files, see *Note option-files::. Before MySQL 5.1.18, the `arg' argument was declared as `char *'. * Return Values * Zero for success. Nonzero if you specify an unknown option. * Example * The following *Note `mysql_options()': mysql-options. calls request the use of compression in the client/server protocol, cause options to be read from the `[odbc]' group of option files, and disable transaction autocommit mode: MYSQL mysql; mysql_init(&mysql); mysql_options(&mysql,MYSQL_OPT_COMPRESS,0); mysql_options(&mysql,MYSQL_READ_DEFAULT_GROUP,"odbc"); mysql_options(&mysql,MYSQL_INIT_COMMAND,"SET autocommit=0"); if (!mysql_real_connect(&mysql,"host","user","passwd","database",0,NULL,0)) { fprintf(stderr, "Failed to connect to database: Error: %s\n", mysql_error(&mysql)); } This code requests that the client use the compressed client/server protocol and read the additional options from the `odbc' section in the `my.cnf' file.  File: manual.info, Node: mysql-ping, Next: mysql-query, Prev: mysql-options, Up: c-api-functions 21.9.3.50 `mysql_ping()' ........................ `int mysql_ping(MYSQL *mysql)' * Description * Checks whether the connection to the server is working. If the connection has gone down and auto-reconnect is enabled an attempt to reconnect is made. If the connection is down and auto-reconnect is disabled, *Note `mysql_ping()': mysql-ping. returns an error. Auto-reconnect is disabled by default. To enable it, call *Note `mysql_options()': mysql-options. with the `MYSQL_OPT_RECONNECT' option. For details, see *Note mysql-options::. *Note `mysql_ping()': mysql-ping. can be used by clients that remain idle for a long while, to check whether the server has closed the connection and reconnect if necessary. If *Note `mysql_ping()': mysql-ping.) does cause a reconnect, there is no explicit indication of it. To determine whether a reconnect occurs, call *Note `mysql_thread_id()': mysql-thread-id. to get the original connection identifier before calling *Note `mysql_ping()': mysql-ping, then call *Note `mysql_thread_id()': mysql-thread-id. again to see whether the identifier has changed. If reconnect occurs, some characteristics of the connection will have been reset. For details about these characteristics, see *Note auto-reconnect::. * Return Values * Zero if the connection to the server is active. Nonzero if an error occurred. A nonzero return does not indicate whether the MySQL server itself is down; the connection might be broken for other reasons such as network problems. * Errors * * `CR_COMMANDS_OUT_OF_SYNC' Commands were executed in an improper order. * `CR_SERVER_GONE_ERROR' The MySQL server has gone away. * `CR_UNKNOWN_ERROR' An unknown error occurred.  File: manual.info, Node: mysql-query, Next: mysql-real-connect, Prev: mysql-ping, Up: c-api-functions 21.9.3.51 `mysql_query()' ......................... `int mysql_query(MYSQL *mysql, const char *stmt_str)' * Description * Executes the SQL statement pointed to by the null-terminated string `stmt_str'. Normally, the string must consist of a single SQL statement and you should not add a terminating semicolon (``;'') or `\g' to the statement. If multiple-statement execution has been enabled, the string can contain several statements separated by semicolons. See *Note c-api-multiple-queries::. *Note `mysql_query()': mysql-query. cannot be used for statements that contain binary data; you must use *Note `mysql_real_query()': mysql-real-query. instead. (Binary data may contain the ``\0'' character, which *Note `mysql_query()': mysql-query. interprets as the end of the statement string.) If you want to know whether the statement should return a result set, you can use *Note `mysql_field_count()': mysql-field-count. to check for this. See *Note mysql-field-count::. * Return Values * Zero if the statement was successful. Nonzero if an error occurred. * Errors * * `CR_COMMANDS_OUT_OF_SYNC' Commands were executed in an improper order. * `CR_SERVER_GONE_ERROR' The MySQL server has gone away. * `CR_SERVER_LOST' The connection to the server was lost during the query. * `CR_UNKNOWN_ERROR' An unknown error occurred.  File: manual.info, Node: mysql-real-connect, Next: mysql-real-escape-string, Prev: mysql-query, Up: c-api-functions 21.9.3.52 `mysql_real_connect()' ................................ `MYSQL *mysql_real_connect(MYSQL *mysql, const char *host, const char *user, const char *passwd, const char *db, unsigned int port, const char *unix_socket, unsigned long client_flag)' * Description * *Note `mysql_real_connect()': mysql-real-connect. attempts to establish a connection to a MySQL database engine running on `host'. *Note `mysql_real_connect()': mysql-real-connect. must complete successfully before you can execute any other API functions that require a valid `MYSQL' connection handle structure. The parameters are specified as follows: * The first parameter should be the address of an existing `MYSQL' structure. Before calling *Note `mysql_real_connect()': mysql-real-connect. you must call *Note `mysql_init()': mysql-init. to initialize the `MYSQL' structure. You can change a lot of connect options with the *Note `mysql_options()': mysql-options. call. See *Note mysql-options::. * The value of `host' may be either a host name or an IP address. If `host' is `NULL' or the string `"localhost"', a connection to the local host is assumed: For Windows, the client connects using a shared-memory connection, if the server has shared-memory connections enabled. Otherwise, TCP/IP is used. For Unix, the client connects using a Unix socket file. For local connections, you can also influence the type of connection to use with the `MYSQL_OPT_PROTOCOL' or `MYSQL_OPT_NAMED_PIPE' options to *Note `mysql_options()': mysql-options. The type of connection must be supported by the server. For a `host' value of `"."' on Windows, the client connects using a named pipe, if the server has named-pipe connections enabled. If named-pipe connections are not enabled, an error occurs. * The `user' parameter contains the user's MySQL login ID. If `user' is `NULL' or the empty string `""', the current user is assumed. Under Unix, this is the current login name. Under Windows ODBC, the current user name must be specified explicitly. See the MyODBC section of *Note connectors-apis::. * The `passwd' parameter contains the password for `user'. If `passwd' is `NULL', only entries in the `user' table for the user that have a blank (empty) password field are checked for a match. This enables the database administrator to set up the MySQL privilege system in such a way that users get different privileges depending on whether they have specified a password. *Note*: Do not attempt to encrypt the password before calling *Note `mysql_real_connect()': mysql-real-connect.; password encryption is handled automatically by the client API. * The `user' and `passwd' parameters use whatever character set has been configured for the `MYSQL' object. By default, this is `latin1', but can be changed by calling *Note `mysql_options(mysql, MYSQL_SET_CHARSET_NAME, "CHARSET_NAME")': mysql-options. prior to connecting. * `db' is the database name. If `db' is not `NULL', the connection sets the default database to this value. * If `port' is not 0, the value is used as the port number for the TCP/IP connection. Note that the `host' parameter determines the type of the connection. * If `unix_socket' is not `NULL', the string specifies the socket or named pipe that should be used. Note that the `host' parameter determines the type of the connection. * The value of `client_flag' is usually 0, but can be set to a combination of the following flags to enable certain features. Flag Name Flag Description `CLIENT_COMPRESS' Use compression protocol. `CLIENT_FOUND_ROWS' Return the number of found (matched) rows, not the number of changed rows. `CLIENT_IGNORE_SIGPIPE' Prevents the client library from installing a `SIGPIPE' signal handler. This can be used to avoid conflicts with a handler that the application has already installed. `CLIENT_IGNORE_SPACE' Permit spaces after function names. Makes all functions names reserved words. `CLIENT_INTERACTIVE' Permit `interactive_timeout' seconds (instead of `wait_timeout' seconds) of inactivity before closing the connection. The client's session `wait_timeout' variable is set to the value of the session `interactive_timeout' variable. `CLIENT_LOCAL_FILES' Enable *Note `LOAD DATA LOCAL': load-data. handling. `CLIENT_MULTI_RESULTS' Tell the server that the client can handle multiple result sets from multiple-statement executions or stored procedures. This flag is automatically enabled if `CLIENT_MULTI_STATEMENTS' is enabled. See the note following this table for more information about this flag. `CLIENT_MULTI_STATEMENTS'Tell the server that the client may send multiple statements in a single string (separated by ``;''). If this flag is not set, multiple-statement execution is disabled. See the note following this table for more information about this flag. `CLIENT_NO_SCHEMA' Do not permit the DB_NAME.TBL_NAME.COL_NAME syntax. This is for ODBC. It causes the parser to generate an error if you use that syntax, which is useful for trapping bugs in some ODBC programs. `CLIENT_ODBC' Unused. `CLIENT_SSL' Use SSL (encrypted protocol). This option should not be set by application programs; it is set internally in the client library. Instead, use *Note `mysql_ssl_set()': mysql-ssl-set. before calling *Note `mysql_real_connect()': mysql-real-connect. `CLIENT_REMEMBER_OPTIONS'Remember options specified by calls to *Note `mysql_options()': mysql-options. Without this option, if *Note `mysql_real_connect()': mysql-real-connect. fails, you must repeat the *Note `mysql_options()': mysql-options. calls before trying to connect again. With this option, the *Note `mysql_options()': mysql-options. calls need not be repeated. If your program uses *Note `CALL': call. statements to execute stored procedures, the `CLIENT_MULTI_RESULTS' flag must be enabled. This is because each *Note `CALL': call. returns a result to indicate the call status, in addition to any result sets that might be returned by statements executed within the procedure. Because *Note `CALL': call. can return multiple results, you should process them using a loop that calls *Note `mysql_next_result()': mysql-next-result. to determine whether there are more results. `CLIENT_MULTI_RESULTS' can be enabled when you call *Note `mysql_real_connect()': mysql-real-connect, either explicitly by passing the `CLIENT_MULTI_RESULTS' flag itself, or implicitly by passing `CLIENT_MULTI_STATEMENTS' (which also enables `CLIENT_MULTI_RESULTS'). If you enable `CLIENT_MULTI_STATEMENTS' or `CLIENT_MULTI_RESULTS', you should process the result for every call to *Note `mysql_query()': mysql-query. or *Note `mysql_real_query()': mysql-real-query. by using a loop that calls *Note `mysql_next_result()': mysql-next-result. to determine whether there are more results. For an example, see *Note c-api-multiple-queries::. For some parameters, it is possible to have the value taken from an option file rather than from an explicit value in the *Note `mysql_real_connect()': mysql-real-connect. call. To do this, call *Note `mysql_options()': mysql-options. with the `MYSQL_READ_DEFAULT_FILE' or `MYSQL_READ_DEFAULT_GROUP' option before calling *Note `mysql_real_connect()': mysql-real-connect. Then, in the *Note `mysql_real_connect()': mysql-real-connect. call, specify the `no-value' value for each parameter to be read from an option file: * For `host', specify a value of `NULL' or the empty string (`""'). * For `user', specify a value of `NULL' or the empty string. * For `passwd', specify a value of `NULL'. (For the password, a value of the empty string in the *Note `mysql_real_connect()': mysql-real-connect. call cannot be overridden in an option file, because the empty string indicates explicitly that the MySQL account must have an empty password.) * For `db', specify a value of `NULL' or the empty string. * For `port', specify a value of 0. * For `unix_socket', specify a value of `NULL'. If no value is found in an option file for a parameter, its default value is used as indicated in the descriptions given earlier in this section. * Return Values * A `MYSQL*' connection handle if the connection was successful, `NULL' if the connection was unsuccessful. For a successful connection, the return value is the same as the value of the first parameter. * Errors * * `CR_CONN_HOST_ERROR' Failed to connect to the MySQL server. * `CR_CONNECTION_ERROR' Failed to connect to the local MySQL server. * `CR_IPSOCK_ERROR' Failed to create an IP socket. * `CR_OUT_OF_MEMORY' Out of memory. * `CR_SOCKET_CREATE_ERROR' Failed to create a Unix socket. * `CR_UNKNOWN_HOST' Failed to find the IP address for the host name. * `CR_VERSION_ERROR' A protocol mismatch resulted from attempting to connect to a server with a client library that uses a different protocol version. * `CR_NAMEDPIPEOPEN_ERROR' Failed to create a named pipe on Windows. * `CR_NAMEDPIPEWAIT_ERROR' Failed to wait for a named pipe on Windows. * `CR_NAMEDPIPESETSTATE_ERROR' Failed to get a pipe handler on Windows. * `CR_SERVER_LOST' If `connect_timeout' > 0 and it took longer than `connect_timeout' seconds to connect to the server or if the server died while executing the `init-command'. * Example * MYSQL mysql; mysql_init(&mysql); mysql_options(&mysql,MYSQL_READ_DEFAULT_GROUP,"your_prog_name"); if (!mysql_real_connect(&mysql,"host","user","passwd","database",0,NULL,0)) { fprintf(stderr, "Failed to connect to database: Error: %s\n", mysql_error(&mysql)); } By using *Note `mysql_options()': mysql-options. the MySQL library reads the `[client]' and `[your_prog_name]' sections in the `my.cnf' file which ensures that your program works, even if someone has set up MySQL in some nonstandard way. Note that upon connection, *Note `mysql_real_connect()': mysql-real-connect. sets the `reconnect' flag (part of the `MYSQL' structure) to a value of `1' in versions of the API older than 5.0.3, or `0' in newer versions. A value of `1' for this flag indicates that if a statement cannot be performed because of a lost connection, to try reconnecting to the server before giving up. You can use the `MYSQL_OPT_RECONNECT' option to *Note `mysql_options()': mysql-options. to control reconnection behavior.  File: manual.info, Node: mysql-real-escape-string, Next: mysql-real-query, Prev: mysql-real-connect, Up: c-api-functions 21.9.3.53 `mysql_real_escape_string()' ...................................... `unsigned long mysql_real_escape_string(MYSQL *mysql, char *to, const char *from, unsigned long length)' Note that `mysql' must be a valid, open connection. This is needed because the escaping depends on the character set in use by the server. * Description * This function is used to create a legal SQL string that you can use in an SQL statement. See *Note string-syntax::. The string in `from' is encoded to an escaped SQL string, taking into account the current character set of the connection. The result is placed in `to' and a terminating null byte is appended. Characters encoded are `NUL' (ASCII 0), ``\n'', ``\r'', ``\'', ``''', ``"'', and Control+Z (see *Note literals::). (Strictly speaking, MySQL requires only that backslash and the quote character used to quote the string in the query be escaped. This function quotes the other characters to make them easier to read in log files.) The string pointed to by `from' must be `length' bytes long. You must allocate the `to' buffer to be at least `length*2+1' bytes long. (In the worst case, each character may need to be encoded as using two bytes, and you need room for the terminating null byte.) When *Note `mysql_real_escape_string()': mysql-real-escape-string. returns, the contents of `to' is a null-terminated string. The return value is the length of the encoded string, not including the terminating null character. If you need to change the character set of the connection, you should use the *Note `mysql_set_character_set()': mysql-set-character-set. function rather than executing a `SET NAMES' (or `SET CHARACTER SET') statement. *Note `mysql_set_character_set()': mysql-set-character-set. works like `SET NAMES' but also affects the character set used by *Note `mysql_real_escape_string()': mysql-real-escape-string, which `SET NAMES' does not. * Example * char query[1000],*end; end = strmov(query,"INSERT INTO test_table values("); *end++ = '\''; end += mysql_real_escape_string(&mysql, end,"What is this",12); *end++ = '\''; *end++ = ','; *end++ = '\''; end += mysql_real_escape_string(&mysql, end,"binary data: \0\r\n",16); *end++ = '\''; *end++ = ')'; if (mysql_real_query(&mysql,query,(unsigned int) (end - query))) { fprintf(stderr, "Failed to insert row, Error: %s\n", mysql_error(&mysql)); } The `strmov()' function used in the example is included in the `mysqlclient' library and works like `strcpy()' but returns a pointer to the terminating null of the first parameter. * Return Values * The length of the value placed into `to', not including the terminating null character. * Errors * None.  File: manual.info, Node: mysql-real-query, Next: mysql-refresh, Prev: mysql-real-escape-string, Up: c-api-functions 21.9.3.54 `mysql_real_query()' .............................. `int mysql_real_query(MYSQL *mysql, const char *stmt_str, unsigned long length)' * Description * Executes the SQL statement pointed to by `stmt_str', which should be a string `length' bytes long. Normally, the string must consist of a single SQL statement and you should not add a terminating semicolon (``;'') or `\g' to the statement. If multiple-statement execution has been enabled, the string can contain several statements separated by semicolons. See *Note c-api-multiple-queries::. *Note `mysql_query()': mysql-query. cannot be used for statements that contain binary data; you must use *Note `mysql_real_query()': mysql-real-query. instead. (Binary data may contain the ``\0'' character, which *Note `mysql_query()': mysql-query. interprets as the end of the statement string.) In addition, *Note `mysql_real_query()': mysql-real-query. is faster than *Note `mysql_query()': mysql-query. because it does not call `strlen()' on the statement string. If you want to know whether the statement should return a result set, you can use *Note `mysql_field_count()': mysql-field-count. to check for this. See *Note mysql-field-count::. * Return Values * Zero if the statement was successful. Nonzero if an error occurred. * Errors * * `CR_COMMANDS_OUT_OF_SYNC' Commands were executed in an improper order. * `CR_SERVER_GONE_ERROR' The MySQL server has gone away. * `CR_SERVER_LOST' The connection to the server was lost during the query. * `CR_UNKNOWN_ERROR' An unknown error occurred.  File: manual.info, Node: mysql-refresh, Next: mysql-reload, Prev: mysql-real-query, Up: c-api-functions 21.9.3.55 `mysql_refresh()' ........................... `int mysql_refresh(MYSQL *mysql, unsigned int options)' * Description * This function flushes tables or caches, or resets replication server information. The connected user must have the `RELOAD' privilege. The `options' argument is a bit mask composed from any combination of the following values. Multiple values can be OR'ed together to perform multiple operations with a single call. * `REFRESH_GRANT' Refresh the grant tables, like *Note `FLUSH PRIVILEGES': flush. * `REFRESH_LOG' Flush the logs, like *Note `FLUSH LOGS': flush. * `REFRESH_TABLES' Flush the table cache, like *Note `FLUSH TABLES': flush. * `REFRESH_HOSTS' Flush the host cache, like *Note `FLUSH HOSTS': flush. * `REFRESH_STATUS' Reset status variables, like `FLUSH STATUS'. * `REFRESH_THREADS' Flush the thread cache. * `REFRESH_SLAVE' On a slave replication server, reset the master server information and restart the slave, like *Note `RESET SLAVE': reset-slave. * `REFRESH_MASTER' On a master replication server, remove the binary log files listed in the binary log index and truncate the index file, like *Note `RESET MASTER': reset-master. * Return Values * Zero for success. Nonzero if an error occurred. * Errors * * `CR_COMMANDS_OUT_OF_SYNC' Commands were executed in an improper order. * `CR_SERVER_GONE_ERROR' The MySQL server has gone away. * `CR_SERVER_LOST' The connection to the server was lost during the query. * `CR_UNKNOWN_ERROR' An unknown error occurred.  File: manual.info, Node: mysql-reload, Next: mysql-rollback, Prev: mysql-refresh, Up: c-api-functions 21.9.3.56 `mysql_reload()' .......................... `int mysql_reload(MYSQL *mysql)' * Description * Asks the MySQL server to reload the grant tables. The connected user must have the `RELOAD' privilege. This function is deprecated. It is preferable to use *Note `mysql_query()': mysql-query. to issue an SQL *Note `FLUSH PRIVILEGES': flush. statement instead. * Return Values * Zero for success. Nonzero if an error occurred. * Errors * * `CR_COMMANDS_OUT_OF_SYNC' Commands were executed in an improper order. * `CR_SERVER_GONE_ERROR' The MySQL server has gone away. * `CR_SERVER_LOST' The connection to the server was lost during the query. * `CR_UNKNOWN_ERROR' An unknown error occurred.  File: manual.info, Node: mysql-rollback, Next: mysql-row-seek, Prev: mysql-reload, Up: c-api-functions 21.9.3.57 `mysql_rollback()' ............................ `my_bool mysql_rollback(MYSQL *mysql)' * Description * Rolls back the current transaction. The action of this function is subject to the value of the `completion_type' system variable. In particular, if the value of `completion_type' is 2, the server performs a release after terminating a transaction and closes the client connection. The client program should call *Note `mysql_close()': mysql-close. to close the connection from the client side. * Return Values * Zero if successful. Nonzero if an error occurred. * Errors * None.  File: manual.info, Node: mysql-row-seek, Next: mysql-row-tell, Prev: mysql-rollback, Up: c-api-functions 21.9.3.58 `mysql_row_seek()' ............................ `MYSQL_ROW_OFFSET mysql_row_seek(MYSQL_RES *result, MYSQL_ROW_OFFSET offset)' * Description * Sets the row cursor to an arbitrary row in a query result set. The `offset' value is a row offset that should be a value returned from *Note `mysql_row_tell()': mysql-row-tell. or from *Note `mysql_row_seek()': mysql-row-seek. This value is not a row number; if you want to seek to a row within a result set by number, use *Note `mysql_data_seek()': mysql-data-seek. instead. This function requires that the result set structure contains the entire result of the query, so *Note `mysql_row_seek()': mysql-row-seek. may be used only in conjunction with *Note `mysql_store_result()': mysql-store-result, not with *Note `mysql_use_result()': mysql-use-result. * Return Values * The previous value of the row cursor. This value may be passed to a subsequent call to *Note `mysql_row_seek()': mysql-row-seek. * Errors * None.  File: manual.info, Node: mysql-row-tell, Next: mysql-select-db, Prev: mysql-row-seek, Up: c-api-functions 21.9.3.59 `mysql_row_tell()' ............................ `MYSQL_ROW_OFFSET mysql_row_tell(MYSQL_RES *result)' * Description * Returns the current position of the row cursor for the last *Note `mysql_fetch_row()': mysql-fetch-row. This value can be used as an argument to *Note `mysql_row_seek()': mysql-row-seek. You should use *Note `mysql_row_tell()': mysql-row-tell. only after *Note `mysql_store_result()': mysql-store-result, not after *Note `mysql_use_result()': mysql-use-result. * Return Values * The current offset of the row cursor. * Errors * None.  File: manual.info, Node: mysql-select-db, Next: mysql-set-character-set, Prev: mysql-row-tell, Up: c-api-functions 21.9.3.60 `mysql_select_db()' ............................. `int mysql_select_db(MYSQL *mysql, const char *db)' * Description * Causes the database specified by `db' to become the default (current) database on the connection specified by `mysql'. In subsequent queries, this database is the default for table references that do not include an explicit database specifier. *Note `mysql_select_db()': mysql-select-db. fails unless the connected user can be authenticated as having permission to use the database. * Return Values * Zero for success. Nonzero if an error occurred. * Errors * * `CR_COMMANDS_OUT_OF_SYNC' Commands were executed in an improper order. * `CR_SERVER_GONE_ERROR' The MySQL server has gone away. * `CR_SERVER_LOST' The connection to the server was lost during the query. * `CR_UNKNOWN_ERROR' An unknown error occurred.  File: manual.info, Node: mysql-set-character-set, Next: mysql-set-local-infile-default, Prev: mysql-select-db, Up: c-api-functions 21.9.3.61 `mysql_set_character_set()' ..................................... `int mysql_set_character_set(MYSQL *mysql, const char *csname)' * Description * This function is used to set the default character set for the current connection. The string `csname' specifies a valid character set name. The connection collation becomes the default collation of the character set. This function works like the `SET NAMES' statement, but also sets the value of `mysql->charset', and thus affects the character set used by *Note `mysql_real_escape_string()': mysql-real-escape-string. * Return Values * Zero for success. Nonzero if an error occurred. * Example * MYSQL mysql; mysql_init(&mysql); if (!mysql_real_connect(&mysql,"host","user","passwd","database",0,NULL,0)) { fprintf(stderr, "Failed to connect to database: Error: %s\n", mysql_error(&mysql)); } if (!mysql_set_character_set(&mysql, "utf8")) { printf("New client character set: %s\n", mysql_character_set_name(&mysql)); }  File: manual.info, Node: mysql-set-local-infile-default, Next: mysql-set-local-infile-handler, Prev: mysql-set-character-set, Up: c-api-functions 21.9.3.62 `mysql_set_local_infile_default()' ............................................ `void mysql_set_local_infile_default(MYSQL *mysql);' * Description * Sets the `LOAD LOCAL DATA INFILE' handler callback functions to the defaults used internally by the C client library. The library calls this function automatically if *Note `mysql_set_local_infile_handler()': mysql-set-local-infile-handler. has not been called or does not supply valid functions for each of its callbacks. * Return Values * None. * Errors * None.  File: manual.info, Node: mysql-set-local-infile-handler, Next: mysql-set-server-option, Prev: mysql-set-local-infile-default, Up: c-api-functions 21.9.3.63 `mysql_set_local_infile_handler()' ............................................ `void mysql_set_local_infile_handler(MYSQL *mysql, int (*local_infile_init)(void **, const char *, void *), int (*local_infile_read)(void *, char *, unsigned int), void (*local_infile_end)(void *), int (*local_infile_error)(void *, char*, unsigned int), void *userdata);' * Description * This function installs callbacks to be used during the execution of *Note `LOAD DATA LOCAL INFILE': load-data. statements. It enables application programs to exert control over local (client-side) data file reading. The arguments are the connection handler, a set of pointers to callback functions, and a pointer to a data area that the callbacks can use to share information. To use *Note `mysql_set_local_infile_handler()': mysql-set-local-infile-handler, you must write the following callback functions: int local_infile_init(void **ptr, const char *filename, void *userdata); The initialization function. This is called once to do any setup necessary, open the data file, allocate data structures, and so forth. The first `void**' argument is a pointer to a pointer. You can set the pointer (that is, `*ptr') to a value that will be passed to each of the other callbacks (as a `void*'). The callbacks can use this pointed-to value to maintain state information. The `userdata' argument is the same value that is passed to *Note `mysql_set_local_infile_handler()': mysql-set-local-infile-handler. The initialization function should return zero for success, nonzero for an error. int local_infile_read(void *ptr, char *buf, unsigned int buf_len); The data-reading function. This is called repeatedly to read the data file. `buf' points to the buffer where the read data should be stored, and `buf_len' is the maximum number of bytes that the callback can read and store in the buffer. (It can read fewer bytes, but should not read more.) The return value is the number of bytes read, or zero when no more data could be read (this indicates EOF). Return a value less than zero if an error occurs. void local_infile_end(void *ptr) The termination function. This is called once after `local_infile_read()' has returned zero (EOF) or an error. This function should deallocate any memory allocated by `local_infile_init()' and perform any other cleanup necessary. It is invoked even if the initialization function returns an error. int local_infile_error(void *ptr, char *error_msg, unsigned int error_msg_len); The error-handling function. This is called to get a textual error message to return to the user in case any of your other functions returns an error. `error_msg' points to the buffer into which the message should be written, and `error_msg_len' is the length of the buffer. The message should be written as a null-terminated string, so the message can be at most `error_msg_len'-1 bytes long. The return value is the error number. Typically, the other callbacks store the error message in the data structure pointed to by `ptr', so that `local_infile_error()' can copy the message from there into `error_msg'. After calling *Note `mysql_set_local_infile_handler()': mysql-set-local-infile-handler. in your C code and passing pointers to your callback functions, you can then issue a *Note `LOAD DATA LOCAL INFILE': load-data. statement (for example, by using *Note `mysql_query()': mysql-query.). The client library automatically invokes your callbacks. The file name specified in *Note `LOAD DATA LOCAL INFILE': load-data. will be passed as the second parameter to the `local_infile_init()' callback. * Return Values * None. * Errors * None.  File: manual.info, Node: mysql-set-server-option, Next: mysql-shutdown, Prev: mysql-set-local-infile-handler, Up: c-api-functions 21.9.3.64 `mysql_set_server_option()' ..................................... `int mysql_set_server_option(MYSQL *mysql, enum enum_mysql_set_option option)' * Description * Enables or disables an option for the connection. `option' can have one of the following values. Option Description `MYSQL_OPTION_MULTI_STATEMENTS_ON' Enable multiple-statement support `MYSQL_OPTION_MULTI_STATEMENTS_OFF' Disable multiple-statement support If you enable multiple-statement support, you should retrieve results from calls to *Note `mysql_query()': mysql-query. or *Note `mysql_real_query()': mysql-real-query. by using a loop that calls *Note `mysql_next_result()': mysql-next-result. to determine whether there are more results. For an example, see *Note c-api-multiple-queries::. Enabling multiple-statement support with `MYSQL_OPTION_MULTI_STATEMENTS_ON' does not have quite the same effect as enabling it by passing the `CLIENT_MULTI_STATEMENTS' flag to *Note `mysql_real_connect()': mysql-real-connect.: `CLIENT_MULTI_STATEMENTS' also enables `CLIENT_MULTI_RESULTS'. If you are using the *Note `CALL': call. SQL statement in your programs, multiple-result support must be enabled; this means that `MYSQL_OPTION_MULTI_STATEMENTS_ON' by itself is insufficient to permit the use of *Note `CALL': call. * Return Values * Zero for success. Nonzero if an error occurred. * Errors * * `CR_COMMANDS_OUT_OF_SYNC' Commands were executed in an improper order. * `CR_SERVER_GONE_ERROR' The MySQL server has gone away. * `CR_SERVER_LOST' The connection to the server was lost during the query. * `ER_UNKNOWN_COM_ERROR' The server didn't support *Note `mysql_set_server_option()': mysql-set-server-option. (which is the case that the server is older than 4.1.1) or the server didn't support the option one tried to set.  File: manual.info, Node: mysql-shutdown, Next: mysql-sqlstate, Prev: mysql-set-server-option, Up: c-api-functions 21.9.3.65 `mysql_shutdown()' ............................ `int mysql_shutdown(MYSQL *mysql, enum mysql_enum_shutdown_level shutdown_level)' * Description * Asks the database server to shut down. The connected user must have the `SHUTDOWN' privilege. MySQL 5.1 servers support only one type of shutdown; `shutdown_level' must be equal to `SHUTDOWN_DEFAULT'. Additional shutdown levels are planned to make it possible to choose the desired level. Dynamically linked executables which have been compiled with older versions of the `libmysqlclient' headers and call *Note `mysql_shutdown()': mysql-shutdown. need to be used with the old `libmysqlclient' dynamic library. The shutdown process is described in *Note server-shutdown::. * Return Values * Zero for success. Nonzero if an error occurred. * Errors * * `CR_COMMANDS_OUT_OF_SYNC' Commands were executed in an improper order. * `CR_SERVER_GONE_ERROR' The MySQL server has gone away. * `CR_SERVER_LOST' The connection to the server was lost during the query. * `CR_UNKNOWN_ERROR' An unknown error occurred.  File: manual.info, Node: mysql-sqlstate, Next: mysql-ssl-set, Prev: mysql-shutdown, Up: c-api-functions 21.9.3.66 `mysql_sqlstate()' ............................ `const char *mysql_sqlstate(MYSQL *mysql)' * Description * Returns a null-terminated string containing the SQLSTATE error code for the most recently executed SQL statement. The error code consists of five characters. `'00000'' means `no error'. The values are specified by ANSI SQL and ODBC. For a list of possible values, see *Note error-handling::. SQLSTATE values returned by *Note `mysql_sqlstate()': mysql-sqlstate. differ from MySQL-specific error numbers returned by *Note `mysql_errno()': mysql-errno. For example, the *Note `mysql': mysql. client program displays errors using the following format, where `1146' is the *Note `mysql_errno()': mysql-errno. value and `'42S02'' is the corresponding *Note `mysql_sqlstate()': mysql-sqlstate. value: shell> SELECT * FROM no_such_table; ERROR 1146 (42S02): Table 'test.no_such_table' doesn't exist Not all MySQL error numbers are mapped to SQLSTATE error codes. The value `'HY000'' (general error) is used for unmapped error numbers. If you call *Note `mysql_sqlstate()': mysql-sqlstate. after *Note `mysql_real_connect()': mysql-real-connect. fails, *Note `mysql_sqlstate()': mysql-sqlstate. might not return a useful value. For example, this happens if a host is blocked by the server and the connection is closed without any SQLSTATE value being sent to the client. * Return Values * A null-terminated character string containing the SQLSTATE error code. * See Also * See *Note mysql-errno::, *Note mysql-error::, and *Note mysql-stmt-sqlstate::.  File: manual.info, Node: mysql-ssl-set, Next: mysql-stat, Prev: mysql-sqlstate, Up: c-api-functions 21.9.3.67 `mysql_ssl_set()' ........................... `my_bool mysql_ssl_set(MYSQL *mysql, const char *key, const char *cert, const char *ca, const char *capath, const char *cipher)' * Description * *Note `mysql_ssl_set()': mysql-ssl-set. is used for establishing secure connections using SSL. It must be called before *Note `mysql_real_connect()': mysql-real-connect. *Note `mysql_ssl_set()': mysql-ssl-set. does nothing unless SSL support is enabled in the client library. `mysql' is the connection handler returned from *Note `mysql_init()': mysql-init. The other parameters are specified as follows: * `key' is the path name to the key file. * `cert' is the path name to the certificate file. * `ca' is the path name to the certificate authority file. * `capath' is the path name to a directory that contains trusted SSL CA certificates in pem format. * `cipher' is a list of permissible ciphers to use for SSL encryption. Any unused SSL parameters may be given as `NULL'. * Return Values * This function always returns `0'. If SSL setup is incorrect, *Note `mysql_real_connect()': mysql-real-connect. returns an error when you attempt to connect.  File: manual.info, Node: mysql-stat, Next: mysql-store-result, Prev: mysql-ssl-set, Up: c-api-functions 21.9.3.68 `mysql_stat()' ........................ `const char *mysql_stat(MYSQL *mysql)' * Description * Returns a character string containing information similar to that provided by the *Note `mysqladmin status': mysqladmin. command. This includes uptime in seconds and the number of running threads, questions, reloads, and open tables. * Return Values * A character string describing the server status. `NULL' if an error occurred. * Errors * * `CR_COMMANDS_OUT_OF_SYNC' Commands were executed in an improper order. * `CR_SERVER_GONE_ERROR' The MySQL server has gone away. * `CR_SERVER_LOST' The connection to the server was lost during the query. * `CR_UNKNOWN_ERROR' An unknown error occurred.  File: manual.info, Node: mysql-store-result, Next: mysql-thread-id, Prev: mysql-stat, Up: c-api-functions 21.9.3.69 `mysql_store_result()' ................................ `MYSQL_RES *mysql_store_result(MYSQL *mysql)' * Description * After invoking *Note `mysql_query()': mysql-query. or *Note `mysql_real_query()': mysql-real-query, you must call *Note `mysql_store_result()': mysql-store-result. or *Note `mysql_use_result()': mysql-use-result. for every statement that successfully produces a result set (*Note `SELECT': select, *Note `SHOW': show, *Note `DESCRIBE': describe, *Note `EXPLAIN': explain, *Note `CHECK TABLE': check-table, and so forth). You must also call *Note `mysql_free_result()': mysql-free-result. after you are done with the result set. You don't have to call *Note `mysql_store_result()': mysql-store-result. or *Note `mysql_use_result()': mysql-use-result. for other statements, but it does not do any harm or cause any notable performance degradation if you call *Note `mysql_store_result()': mysql-store-result. in all cases. You can detect whether the statement has a result set by checking whether *Note `mysql_store_result()': mysql-store-result. returns a nonzero value (more about this later on). If you enable multiple-statement support, you should retrieve results from calls to *Note `mysql_query()': mysql-query. or *Note `mysql_real_query()': mysql-real-query. by using a loop that calls *Note `mysql_next_result()': mysql-next-result. to determine whether there are more results. For an example, see *Note c-api-multiple-queries::. If you want to know whether a statement should return a result set, you can use *Note `mysql_field_count()': mysql-field-count. to check for this. See *Note mysql-field-count::. *Note `mysql_store_result()': mysql-store-result. reads the entire result of a query to the client, allocates a `MYSQL_RES' structure, and places the result into this structure. *Note `mysql_store_result()': mysql-store-result. returns a null pointer if the statement didn't return a result set (for example, if it was an *Note `INSERT': insert. statement). *Note `mysql_store_result()': mysql-store-result. also returns a null pointer if reading of the result set failed. You can check whether an error occurred by checking whether *Note `mysql_error()': mysql-error. returns a nonempty string, *Note `mysql_errno()': mysql-errno. returns nonzero, or *Note `mysql_field_count()': mysql-field-count. returns zero. An empty result set is returned if there are no rows returned. (An empty result set differs from a null pointer as a return value.) After you have called *Note `mysql_store_result()': mysql-store-result. and gotten back a result that isn't a null pointer, you can call *Note `mysql_num_rows()': mysql-num-rows. to find out how many rows are in the result set. You can call *Note `mysql_fetch_row()': mysql-fetch-row. to fetch rows from the result set, or *Note `mysql_row_seek()': mysql-row-seek. and *Note `mysql_row_tell()': mysql-row-tell. to obtain or set the current row position within the result set. See *Note null-mysql-store-result::. * Return Values * A `MYSQL_RES' result structure with the results. `NULL' (0) if an error occurred. * Errors * *Note `mysql_store_result()': mysql-store-result. resets *Note `mysql_error()': mysql-error. and *Note `mysql_errno()': mysql-errno. if it succeeds. * `CR_COMMANDS_OUT_OF_SYNC' Commands were executed in an improper order. * `CR_OUT_OF_MEMORY' Out of memory. * `CR_SERVER_GONE_ERROR' The MySQL server has gone away. * `CR_SERVER_LOST' The connection to the server was lost during the query. * `CR_UNKNOWN_ERROR' An unknown error occurred.  File: manual.info, Node: mysql-thread-id, Next: mysql-use-result, Prev: mysql-store-result, Up: c-api-functions 21.9.3.70 `mysql_thread_id()' ............................. `unsigned long mysql_thread_id(MYSQL *mysql)' * Description * Returns the thread ID of the current connection. This value can be used as an argument to *Note `mysql_kill()': mysql-kill. to kill the thread. If the connection is lost and you reconnect with *Note `mysql_ping()': mysql-ping, the thread ID changes. This means you should not get the thread ID and store it for later. You should get it when you need it. * Return Values * The thread ID of the current connection. * Errors * None.  File: manual.info, Node: mysql-use-result, Next: mysql-warning-count, Prev: mysql-thread-id, Up: c-api-functions 21.9.3.71 `mysql_use_result()' .............................. `MYSQL_RES *mysql_use_result(MYSQL *mysql)' * Description * After invoking *Note `mysql_query()': mysql-query. or *Note `mysql_real_query()': mysql-real-query, you must call *Note `mysql_store_result()': mysql-store-result. or *Note `mysql_use_result()': mysql-use-result. for every statement that successfully produces a result set (*Note `SELECT': select, *Note `SHOW': show, *Note `DESCRIBE': describe, *Note `EXPLAIN': explain, *Note `CHECK TABLE': check-table, and so forth). You must also call *Note `mysql_free_result()': mysql-free-result. after you are done with the result set. *Note `mysql_use_result()': mysql-use-result. initiates a result set retrieval but does not actually read the result set into the client like *Note `mysql_store_result()': mysql-store-result. does. Instead, each row must be retrieved individually by making calls to *Note `mysql_fetch_row()': mysql-fetch-row. This reads the result of a query directly from the server without storing it in a temporary table or local buffer, which is somewhat faster and uses much less memory than *Note `mysql_store_result()': mysql-store-result. The client allocates memory only for the current row and a communication buffer that may grow up to `max_allowed_packet' bytes. On the other hand, you shouldn't use *Note `mysql_use_result()': mysql-use-result. if you are doing a lot of processing for each row on the client side, or if the output is sent to a screen on which the user may type a `^S' (stop scroll). This ties up the server and prevent other threads from updating any tables from which the data is being fetched. When using *Note `mysql_use_result()': mysql-use-result, you must execute *Note `mysql_fetch_row()': mysql-fetch-row. until a `NULL' value is returned, otherwise, the unfetched rows are returned as part of the result set for your next query. The C API gives the error `Commands out of sync; you can't run this command now' if you forget to do this! You may not use *Note `mysql_data_seek()': mysql-data-seek, *Note `mysql_row_seek()': mysql-row-seek, *Note `mysql_row_tell()': mysql-row-tell, *Note `mysql_num_rows()': mysql-num-rows, or *Note `mysql_affected_rows()': mysql-affected-rows. with a result returned from *Note `mysql_use_result()': mysql-use-result, nor may you issue other queries until *Note `mysql_use_result()': mysql-use-result. has finished. (However, after you have fetched all the rows, *Note `mysql_num_rows()': mysql-num-rows. accurately returns the number of rows fetched.) You must call *Note `mysql_free_result()': mysql-free-result. once you are done with the result set. When using the `libmysqld' embedded server, the memory benefits are essentially lost because memory usage incrementally increases with each row retrieved until *Note `mysql_free_result()': mysql-free-result. is called. * Return Values * A `MYSQL_RES' result structure. `NULL' if an error occurred. * Errors * *Note `mysql_use_result()': mysql-use-result. resets *Note `mysql_error()': mysql-error. and *Note `mysql_errno()': mysql-errno. if it succeeds. * `CR_COMMANDS_OUT_OF_SYNC' Commands were executed in an improper order. * `CR_OUT_OF_MEMORY' Out of memory. * `CR_SERVER_GONE_ERROR' The MySQL server has gone away. * `CR_SERVER_LOST' The connection to the server was lost during the query. * `CR_UNKNOWN_ERROR' An unknown error occurred.  File: manual.info, Node: mysql-warning-count, Prev: mysql-use-result, Up: c-api-functions 21.9.3.72 `mysql_warning_count()' ................................. `unsigned int mysql_warning_count(MYSQL *mysql)' * Description * Returns the number of warnings generated during execution of the previous SQL statement. * Return Values * The warning count. * Errors * None.  File: manual.info, Node: c-api-prepared-statements, Next: c-api-prepared-statement-data-structures, Prev: c-api-functions, Up: c 21.9.4 C API Prepared Statements -------------------------------- The MySQL client/server protocol provides for the use of prepared statements. This capability uses the `MYSQL_STMT' statement handler data structure returned by the *Note `mysql_stmt_init()': mysql-stmt-init. initialization function. Prepared execution is an efficient way to execute a statement more than once. The statement is first parsed to prepare it for execution. Then it is executed one or more times at a later time, using the statement handle returned by the initialization function. Prepared execution is faster than direct execution for statements executed more than once, primarily because the query is parsed only once. In the case of direct execution, the query is parsed every time it is executed. Prepared execution also can provide a reduction of network traffic because for each execution of the prepared statement, it is necessary only to send the data for the parameters. Prepared statements might not provide a performance increase in some situations. For best results, test your application both with prepared and nonprepared statements and choose whichever yields best performance. Another advantage of prepared statements is that it uses a binary protocol that makes data transfer between client and server more efficient. The following SQL statements can be used as prepared statements: *Note `CALL': call, *Note `CREATE TABLE': create-table, *Note `DELETE': delete, *Note `DO': do, *Note `INSERT': insert, *Note `REPLACE': replace, *Note `SELECT': select, *Note `SET': set-option, *Note `UPDATE': update, and most *Note `SHOW': show. statements. As of MySQL 5.1.10, the following additional statements are supported: ANALYZE TABLE OPTIMIZE TABLE REPAIR TABLE As of MySQL 5.1.12, the following additional statements are supported: CACHE INDEX CHANGE MASTER CHECKSUM {TABLE | TABLES} {CREATE | RENAME | DROP} DATABASE {CREATE | RENAME | DROP} USER FLUSH {TABLE | TABLES | TABLES WITH READ LOCK | HOSTS | PRIVILEGES | LOGS | STATUS | MASTER | SLAVE | DES_KEY_FILE | USER_RESOURCES} GRANT REVOKE KILL LOAD INDEX INTO CACHE RESET {MASTER | SLAVE | QUERY CACHE} SHOW BINLOG EVENTS SHOW CREATE {PROCEDURE | FUNCTION | EVENT | TABLE | VIEW} SHOW {AUTHORS | CONTRIBUTORS | WARNINGS | ERRORS} SHOW {MASTER | BINARY} LOGS SHOW {MASTER | SLAVE} STATUS SLAVE {START | STOP} INSTALL PLUGIN UNINSTALL PLUGIN Other statements are not yet supported in MySQL 5.1. As of MySQL 5.1.25, metadata changes to tables or views referred to by prepared statements are detected and cause automatic repreparation of the statement when it is next executed. For more information, see *Note statement-repreparation::.  File: manual.info, Node: c-api-prepared-statement-data-structures, Next: c-api-prepared-statement-function-overview, Prev: c-api-prepared-statements, Up: c 21.9.5 C API Prepared Statement Data Structures ----------------------------------------------- * Menu: * c-api-prepared-statement-type-codes:: C API Prepared Statement Type Codes * c-api-prepared-statement-type-conversions:: C API Prepared Statement Type Conversions Prepared statements use several data structures: * To obtain a statement handle, pass a `MYSQL' connection handler to *Note `mysql_stmt_init()': mysql-stmt-init, which returns a pointer to a `MYSQL_STMT' data structure. This structure is used for further operations with the statement. To specify the statement to prepare, pass the `MYSQL_STMT' pointer and the statement string to *Note `mysql_stmt_prepare()': mysql-stmt-prepare. * To provide input parameters for a prepared statement, set up `MYSQL_BIND' structures and pass them to *Note `mysql_stmt_bind_param()': mysql-stmt-bind-param. To receive output column values, set up `MYSQL_BIND' structures and pass them to *Note `mysql_stmt_bind_result()': mysql-stmt-bind-result. * The `MYSQL_TIME' structure is used to transfer temporal data in both directions. The following discussion describes the prepared statement data types in detail. For examples that show how to use them, see *Note mysql-stmt-execute::, and *Note mysql-stmt-fetch::. * `MYSQL_STMT' This structure is a handle for a prepared statement. A handle is created by calling *Note `mysql_stmt_init()': mysql-stmt-init, which returns a pointer to a `MYSQL_STMT'. The handle is used for all subsequent operations with the statement until you close it with *Note `mysql_stmt_close()': mysql-stmt-close, at which point the handle becomes invalid. The `MYSQL_STMT' structure has no members intended for application use. Applications should not try to copy a `MYSQL_STMT' structure. There is no guarantee that such a copy will be usable. Multiple statement handles can be associated with a single connection. The limit on the number of handles depends on the available system resources. * `MYSQL_BIND' This structure is used both for statement input (data values sent to the server) and output (result values returned from the server): * For input, use `MYSQL_BIND' structures with *Note `mysql_stmt_bind_param()': mysql-stmt-bind-param. to bind parameter data values to buffers for use by *Note `mysql_stmt_execute()': mysql-stmt-execute. * For output, use `MYSQL_BIND' structures with *Note `mysql_stmt_bind_result()': mysql-stmt-bind-result. to bind buffers to result set columns, for use in fetching rows with *Note `mysql_stmt_fetch()': mysql-stmt-fetch. To use a `MYSQL_BIND' structure, zero its contents to initialize it, then set its members appropriately. For example, to declare and initialize an array of three `MYSQL_BIND' structures, use this code: MYSQL_BIND bind[3]; memset(bind, 0, sizeof(bind)); The `MYSQL_BIND' structure contains the following members for use by application programs. For several of the members, the manner of use depends on whether the structure is used for input or output. * `enum enum_field_types buffer_type' The type of the buffer. This member indicates the data type of the C language variable bound to a statement parameter or result set column. For input, `buffer_type' indicates the type of the variable containing the value to be sent to the server. For output, it indicates the type of the variable into which a value received from the server should be stored. For permissible `buffer_type' values, see *Note c-api-prepared-statement-type-codes::. * `void *buffer' A pointer to the buffer to be used for data transfer. This is the address of a C language variable. For input, `buffer' is a pointer to the variable in which you store the data value for a statement parameter. When you call *Note `mysql_stmt_execute()': mysql-stmt-execute, MySQL use the value stored in the variable in place of the corresponding parameter marker in the statement (specified with `?' in the statement string). For output, `buffer' is a pointer to the variable in which to return a result set column value. When you call *Note `mysql_stmt_fetch()': mysql-stmt-fetch, MySQL stores a column value from the current row of the result set in this variable. You can access the value when the call returns. To minimize the need for MySQL to perform type conversions between C language values on the client side and SQL values on the server side, use C variables that have types similar to those of the corresponding SQL values: * For numeric data types, `buffer' should point to a variable of the proper numeric C type. For integer variables (which can be `char' for single-byte values or an integer type for larger values), you should also indicate whether the variable has the `unsigned' attribute by setting the `is_unsigned' member, described later. * For character (nonbinary) and binary string data types, `buffer' should point to a character buffer. * For date and time data types, `buffer' should point to a `MYSQL_TIME' structure. For guidelines about mapping between C types and SQL types and notes about type conversions, see *Note c-api-prepared-statement-type-codes::, and *Note c-api-prepared-statement-type-conversions::. * `unsigned long buffer_length' The actual size of `*buffer' in bytes. This indicates the maximum amount of data that can be stored in the buffer. For character and binary C data, the `buffer_length' value specifies the length of `*buffer' when used with *Note `mysql_stmt_bind_param()': mysql-stmt-bind-param. to specify input values, or the maximum number of output data bytes that can be fetched into the buffer when used with *Note `mysql_stmt_bind_result()': mysql-stmt-bind-result. * `unsigned long *length' A pointer to an `unsigned long' variable that indicates the actual number of bytes of data stored in `*buffer'. `length' is used for character or binary C data. For input parameter data binding, set `*length' to indicate the actual length of the parameter value stored in `*buffer'. This is used by *Note `mysql_stmt_execute()': mysql-stmt-execute. For output value binding, MySQL sets `*length' when you call *Note `mysql_stmt_fetch()': mysql-stmt-fetch. The *Note `mysql_stmt_fetch()': mysql-stmt-fetch. return value determines how to interpret the length: * If the return value is 0, `*length' indicates the actual length of the parameter value. * If the return value is `MYSQL_DATA_TRUNCATED', `*length' indicates the nontruncated length of the parameter value. In this case, the minimum of `*length' and `buffer_length' indicates the actual length of the value. `length' is ignored for numeric and temporal data types because the `buffer_type' value determines the length of the data value. If you must determine the length of a returned value before fetching it, see *Note mysql-stmt-fetch::, for some strategies. * `my_bool *is_null' This member points to a `my_bool' variable that is true if a value is `NULL', false if it is not `NULL'. For input, set `*is_null' to true to indicate that you are passing a `NULL' value as a statement parameter. `is_null' is a _pointer_ to a boolean scalar, not a boolean scalar, to provide flexibility in how you specify `NULL' values: * If your data values are always `NULL', use `MYSQL_TYPE_NULL' as the `buffer_type' value when you bind the column. The other `MYSQL_BIND' members, including `is_null', do not matter. * If your data values are always `NOT NULL', set `is_null = (my_bool*) 0', and set the other members appropriately for the variable you are binding. * In all other cases, set the other members appropriately and set `is_null' to the address of a `my_bool' variable. Set that variable's value to true or false appropriately between executions to indicate whether the corresponding data value is `NULL' or `NOT NULL', respectively. For output, when you fetch a row, MySQL sets the value pointed to by `is_null' to true or false according to whether the result set column value returned from the statement is or is not `NULL'. * `my_bool is_unsigned' This member applies for C variables with data types that can be `unsigned' (`char', `short int', `int', `long long int'). Set `is_unsigned' to true if the variable pointed to by `buffer' is `unsigned' and false otherwise. For example, if you bind a `signed char' variable to `buffer', specify a type code of `MYSQL_TYPE_TINY' and set `is_unsigned' to false. If you bind an `unsigned char' instead, the type code is the same but `is_unsigned' should be true. (For `char', it is not defined whether it is signed or unsigned, so it is best to be explicit about signedness by using `signed char' or `unsigned char'.) `is_unsigned' applies only to the C language variable on the client side. It indicates nothing about the signedness of the corresponding SQL value on the server side. For example, if you use an `int' variable to supply a value for a `BIGINT UNSIGNED' column, `is_unsigned' should be false because `int' is a signed type. If you use an `unsigned int' variable to supply a value for a *Note `BIGINT': numeric-types. column, `is_unsigned' should be true because `unsigned int' is an unsigned type. MySQL performs the proper conversion between signed and unsigned values in both directions, although a warning occurs if truncation results. * `my_bool *error' For output, set this member to point to a `my_bool' variable to have truncation information for the parameter stored there after a row fetching operation. When truncation reporting is enabled, *Note `mysql_stmt_fetch()': mysql-stmt-fetch. returns `MYSQL_DATA_TRUNCATED' and `*error' is true in the `MYSQL_BIND' structures for parameters in which truncation occurred. Truncation indicates loss of sign or significant digits, or that a string was too long to fit in a column. Truncation reporting is enabled by default, but can be controlled by calling *Note `mysql_options()': mysql-options. with the `MYSQL_REPORT_DATA_TRUNCATION' option. * `MYSQL_TIME' This structure is used to send and receive *Note `DATE': datetime, *Note `TIME': time, *Note `DATETIME': datetime, and *Note `TIMESTAMP': datetime. data directly to and from the server. Set the `buffer' member to point to a `MYSQL_TIME' structure, and set the `buffer_type' member of a `MYSQL_BIND' structure to one of the temporal types (`MYSQL_TYPE_TIME', `MYSQL_TYPE_DATE', `MYSQL_TYPE_DATETIME', `MYSQL_TYPE_TIMESTAMP'). The `MYSQL_TIME' structure contains the members listed in the following table. Member Description `unsigned int year' The year `unsigned int month' The month of the year `unsigned int day' The day of the month `unsigned int hour' The hour of the day `unsigned int minute' The minute of the hour `unsigned int second' The second of the minute `my_bool neg' A boolean flag indicating whether the time is negative `unsigned long second_part' The fractional part of the second in microseconds; currently unused Only those parts of a `MYSQL_TIME' structure that apply to a given type of temporal value are used. The `year', `month', and `day' elements are used for *Note `DATE': datetime, *Note `DATETIME': datetime, and *Note `TIMESTAMP': datetime. values. The `hour', `minute', and `second' elements are used for *Note `TIME': time, *Note `DATETIME': datetime, and *Note `TIMESTAMP': datetime. values. See *Note c-api-prepared-statement-date-handling::.  File: manual.info, Node: c-api-prepared-statement-type-codes, Next: c-api-prepared-statement-type-conversions, Prev: c-api-prepared-statement-data-structures, Up: c-api-prepared-statement-data-structures 21.9.5.1 C API Prepared Statement Type Codes ............................................ The `buffer_type' member of `MYSQL_BIND' structures indicates the data type of the C language variable bound to a statement parameter or result set column. For input, `buffer_type' indicates the type of the variable containing the value to be sent to the server. For output, it indicates the type of the variable into which a value received from the server should be stored. The following table shows the permissible values for the `buffer_type' member of `MYSQL_BIND' structures for input values sent to the server. The table shows the C variable types that you can use, the corresponding type codes, and the SQL data types for which the supplied value can be used without conversion. Choose the `buffer_type' value according to the data type of the C language variable that you are binding. For the integer types, you should also set the `is_unsigned' member to indicate whether the variable is signed or unsigned. Input Variable C Type `buffer_type' Value SQL Type of Destination Value `signed char' `MYSQL_TYPE_TINY' *Note `TINYINT': numeric-types. `short int' `MYSQL_TYPE_SHORT' *Note `SMALLINT': numeric-types. `int' `MYSQL_TYPE_LONG' *Note `INT': numeric-types. `long long int' `MYSQL_TYPE_LONGLONG' *Note `BIGINT': numeric-types. `float' `MYSQL_TYPE_FLOAT' *Note `FLOAT': numeric-types. `double' `MYSQL_TYPE_DOUBLE' *Note `DOUBLE': numeric-types. `MYSQL_TIME' `MYSQL_TYPE_TIME' *Note `TIME': time. `MYSQL_TIME' `MYSQL_TYPE_DATE' *Note `DATE': datetime. `MYSQL_TIME' `MYSQL_TYPE_DATETIME' *Note `DATETIME': datetime. `MYSQL_TIME' `MYSQL_TYPE_TIMESTAMP' *Note `TIMESTAMP': datetime. `char[]' `MYSQL_TYPE_STRING' *Note `TEXT': blob, *Note `CHAR': char, *Note `VARCHAR': char. `char[]' `MYSQL_TYPE_BLOB' *Note `BLOB': blob, *Note `BINARY': binary-varbinary, *Note `VARBINARY': binary-varbinary. `MYSQL_TYPE_NULL' `NULL' Use `MYSQL_TYPE_NULL' as indicated in the description for the `is_null' member in *Note c-api-prepared-statement-data-structures::. For input string data, use `MYSQL_TYPE_STRING' or `MYSQL_TYPE_BLOB' depending on whether the value is a character (nonbinary) or binary string: * `MYSQL_TYPE_STRING' indicates character input string data. The value is assumed to be in the character set indicated by the `character_set_client' system variable. If the server stores the value into a column with a different character set, it converts the value to that character set. * `MYSQL_TYPE_BLOB' indicates binary input string data. The value is treated as having the `binary' character set. That is, it is treated as a byte string and no conversion occurs. The following table shows the permissible values for the `buffer_type' member of `MYSQL_BIND' structures for output values received from the server. The table shows the SQL types of received values, the corresponding type codes that such values have in result set metadata, and the recommended C language data types to bind to the `MYSQL_BIND' structure to receive the SQL values without conversion. Choose the `buffer_type' value according to the data type of the C language variable that you are binding. For the integer types, you should also set the `is_unsigned' member to indicate whether the variable is signed or unsigned. SQL Type of Received `buffer_type' Value Output Variable C Type Value *Note `TINYINT': `MYSQL_TYPE_TINY' `signed char' numeric-types. *Note `SMALLINT': `MYSQL_TYPE_SHORT' `short int' numeric-types. *Note `MEDIUMINT': `MYSQL_TYPE_INT24' `int' numeric-types. *Note `INT': `MYSQL_TYPE_LONG' `int' numeric-types. *Note `BIGINT': `MYSQL_TYPE_LONGLONG' `long long int' numeric-types. *Note `FLOAT': `MYSQL_TYPE_FLOAT' `float' numeric-types. *Note `DOUBLE': `MYSQL_TYPE_DOUBLE' `double' numeric-types. *Note `DECIMAL': `MYSQL_TYPE_NEWDECIMAL' `char[]' numeric-types. *Note `YEAR': year. `MYSQL_TYPE_SHORT' `short int' *Note `TIME': time. `MYSQL_TYPE_TIME' `MYSQL_TIME' *Note `DATE': `MYSQL_TYPE_DATE' `MYSQL_TIME' datetime. *Note `DATETIME': `MYSQL_TYPE_DATETIME' `MYSQL_TIME' datetime. *Note `TIMESTAMP': `MYSQL_TYPE_TIMESTAMP' `MYSQL_TIME' datetime. *Note `CHAR': char, `MYSQL_TYPE_STRING' `char[]' *Note `BINARY': binary-varbinary. *Note `VARCHAR': char, `MYSQL_TYPE_VAR_STRING' `char[]' *Note `VARBINARY': binary-varbinary. *Note `TINYBLOB': `MYSQL_TYPE_TINY_BLOB' `char[]' blob, *Note `TINYTEXT': blob. *Note `BLOB': blob, `MYSQL_TYPE_BLOB' `char[]' *Note `TEXT': blob. *Note `MEDIUMBLOB': `MYSQL_TYPE_MEDIUM_BLOB' `char[]' blob, *Note `MEDIUMTEXT': blob. *Note `LONGBLOB': `MYSQL_TYPE_LONG_BLOB' `char[]' blob, *Note `LONGTEXT': blob. *Note `BIT': `MYSQL_TYPE_BIT' `char[]' numeric-types.  File: manual.info, Node: c-api-prepared-statement-type-conversions, Prev: c-api-prepared-statement-type-codes, Up: c-api-prepared-statement-data-structures 21.9.5.2 C API Prepared Statement Type Conversions .................................................. Prepared statements transmit data between the client and server using C language variables on the client side that correspond to SQL values on the server side. If there is a mismatch between the C variable type on the client side and the corresponding SQL value type on the server side, MySQL performs implicit type conversions in both directions. MySQL knows the type code for the SQL value on the server side. The `buffer_type' value in the `MYSQL_BIND' structure indicates the type code of the C variable that holds the value on the client side. The two codes together tell MySQL what conversion must be performed, if any. Here are some examples: * If you use `MYSQL_TYPE_LONG' with an `int' variable to pass an integer value to the server that is to be stored into a *Note `FLOAT': numeric-types. column, MySQL converts the value to floating-point format before storing it. * If you fetch an SQL *Note `MEDIUMINT': numeric-types. column value, but specify a `buffer_type' value of `MYSQL_TYPE_LONGLONG' and use a C variable of type `long long int' as the destination buffer, MySQL converts the *Note `MEDIUMINT': numeric-types. value (which requires less than 8 bytes) for storage into the `long long int' (an 8-byte variable). * If you fetch a numeric column with a value of 255 into a `char[4]' character array and specify a `buffer_type' value of `MYSQL_TYPE_STRING', the resulting value in the array is a 4-byte string `'255\0''. * MySQL returns *Note `DECIMAL': numeric-types. values as the string representation of the original server-side value, which is why the corresponding C type is `char[]'. For example, `12.345' is returned to the client as `'12.345''. If you specify `MYSQL_TYPE_NEWDECIMAL' and bind a string buffer to the `MYSQL_BIND' structure, *Note `mysql_stmt_fetch()': mysql-stmt-fetch. stores the value in the buffer as a string without conversion. If instead you specify a numeric variable and type code, *Note `mysql_stmt_fetch()': mysql-stmt-fetch. converts the string-format *Note `DECIMAL': numeric-types. value to numeric form. * For the `MYSQL_TYPE_BIT' type code, *Note `BIT': numeric-types. values are returned into a string buffer, which is why the corresponding C type is `char[]'. The value represents a bit string that requires interpretation on the client side. To return the value as a type that is easier to deal with, you can cause the value to be cast to integer using either of the following types of expressions: SELECT bit_col + 0 FROM t SELECT CAST(bit_col AS UNSIGNED) FROM t To retrieve the value, bind an integer variable large enough to hold the value and specify the appropriate corresponding integer type code. Before binding variables to the `MYSQL_BIND' structures that are to be used for fetching column values, you can check the type codes for each column of the result set. This might be desirable if you want to determine which variable types would be best to use to avoid type conversions. To get the type codes, call *Note `mysql_stmt_result_metadata()': mysql-stmt-result-metadata. after executing the prepared statement with *Note `mysql_stmt_execute()': mysql-stmt-execute. The metadata provides access to the type codes for the result set as described in *Note mysql-stmt-result-metadata::, and *Note c-api-data-structures::. To determine whether output string values in a result set returned from the server contain binary or nonbinary data, check whether the `charsetnr' value of the result set metadata is 63 (see *Note c-api-data-structures::). If so, the character set is `binary', which indicates binary rather than nonbinary data. This enables you to distinguish *Note `BINARY': binary-varbinary. from *Note `CHAR': char, *Note `VARBINARY': binary-varbinary. from *Note `VARCHAR': char, and the *Note `BLOB': blob. types from the *Note `TEXT': blob. types. If you cause the `max_length' member of the `MYSQL_FIELD' column metadata structures to be set (by calling *Note `mysql_stmt_attr_set()': mysql-stmt-attr-set.), be aware that the `max_length' values for the result set indicate the lengths of the longest string representation of the result values, not the lengths of the binary representation. That is, `max_length' does not necessarily correspond to the size of the buffers needed to fetch the values with the binary protocol used for prepared statements. Choose the size of the buffers according to the types of the variables into which you fetch the values. For example, a `TINYINT' column containing the value -128 might have a `max_length' value of 4. But the binary representation of any `TINYINT' value requires only 1 byte for storage, so you can supply a `signed char' variable in which to store the value and set `is_unsigned' to indicate that values are signed. As of MySQL 5.1.25, metadata changes to tables or views referred to by prepared statements are detected and cause automatic repreparation of the statement when it is next executed. For more information, see *Note statement-repreparation::.  File: manual.info, Node: c-api-prepared-statement-function-overview, Next: c-api-prepared-statement-functions, Prev: c-api-prepared-statement-data-structures, Up: c 21.9.6 C API Prepared Statement Function Overview ------------------------------------------------- The functions available for prepared statement processing are summarized here and described in greater detail in a later section. See *Note c-api-prepared-statement-functions::. Function Description *Note Returns the number of rows changed, deleted, or `mysql_stmt_affected_rows()':inserted by prepared *Note `UPDATE': update, mysql-stmt-affected-rows.*Note `DELETE': delete, or *Note `INSERT': insert. statement *Note Gets value of an attribute for a prepared `mysql_stmt_attr_get()':statement mysql-stmt-attr-get. *Note Sets an attribute for a prepared statement `mysql_stmt_attr_set()': mysql-stmt-attr-set. *Note Associates application data buffers with the `mysql_stmt_bind_param()':parameter markers in a prepared SQL statement mysql-stmt-bind-param. *Note Associates application data buffers with columns `mysql_stmt_bind_result()':in a result set mysql-stmt-bind-result. *Note Frees memory used by a prepared statement `mysql_stmt_close()': mysql-stmt-close. *Note Seeks to an arbitrary row number in a statement `mysql_stmt_data_seek()':result set mysql-stmt-data-seek. *Note Returns the error number for the last statement `mysql_stmt_errno()': execution mysql-stmt-errno. *Note Returns the error message for the last statement `mysql_stmt_error()': execution mysql-stmt-error. *Note Executes a prepared statement `mysql_stmt_execute()': mysql-stmt-execute. *Note Fetches the next row of data from a result set `mysql_stmt_fetch()': and returns data for all bound columns mysql-stmt-fetch. *Note Fetch data for one column of the current row of `mysql_stmt_fetch_column()':a result set mysql-stmt-fetch-column. *Note Returns the number of result columns for the `mysql_stmt_field_count()':most recent statement mysql-stmt-field-count. *Note Free the resources allocated to a statement `mysql_stmt_free_result()':handle mysql-stmt-free-result. *Note Allocates memory for a `MYSQL_STMT' structure and `mysql_stmt_init()': initializes it mysql-stmt-init. *Note Returns the ID generated for an `AUTO_INCREMENT' `mysql_stmt_insert_id()':column by a prepared statement mysql-stmt-insert-id. *Note Returns the row count from a buffered statement `mysql_stmt_num_rows()':result set mysql-stmt-num-rows. *Note Returns the number of parameters in a prepared `mysql_stmt_param_count()':statement mysql-stmt-param-count. *Note (Return parameter metadata in the form of a `mysql_stmt_param_metadata()':result set) Currently, this function does nothing mysql-stmt-param-metadata. *Note Prepares an SQL statement string for execution `mysql_stmt_prepare()': mysql-stmt-prepare. *Note Resets the statement buffers in the server `mysql_stmt_reset()': mysql-stmt-reset. *Note Returns prepared statement metadata in the form `mysql_stmt_result_metadata()':of a result set mysql-stmt-result-metadata. *Note Seeks to a row offset in a statement result set, `mysql_stmt_row_seek()':using value returned from *Note mysql-stmt-row-seek. `mysql_stmt_row_tell()': mysql-stmt-row-tell. *Note Returns the statement row cursor position `mysql_stmt_row_tell()': mysql-stmt-row-tell. *Note Sends long data in chunks to server `mysql_stmt_send_long_data()': mysql-stmt-send-long-data. *Note Returns the SQLSTATE error code for the last `mysql_stmt_sqlstate()':statement execution mysql-stmt-sqlstate. *Note Retrieves a complete result set to the client `mysql_stmt_store_result()': mysql-stmt-store-result. Call *Note `mysql_stmt_init()': mysql-stmt-init. to create a statement handle, then *Note `mysql_stmt_prepare()': mysql-stmt-prepare. to prepare the statement string, *Note `mysql_stmt_bind_param()': mysql-stmt-bind-param. to supply the parameter data, and *Note `mysql_stmt_execute()': mysql-stmt-execute. to execute the statement. You can repeat the *Note `mysql_stmt_execute()': mysql-stmt-execute. by changing parameter values in the respective buffers supplied through *Note `mysql_stmt_bind_param()': mysql-stmt-bind-param. You can send text or binary data in chunks to server using *Note `mysql_stmt_send_long_data()': mysql-stmt-send-long-data. See *Note mysql-stmt-send-long-data::. If the statement is a *Note `SELECT': select. or any other statement that produces a result set, *Note `mysql_stmt_prepare()': mysql-stmt-prepare. also returns the result set metadata information in the form of a `MYSQL_RES' result set through *Note `mysql_stmt_result_metadata()': mysql-stmt-result-metadata. You can supply the result buffers using *Note `mysql_stmt_bind_result()': mysql-stmt-bind-result, so that the *Note `mysql_stmt_fetch()': mysql-stmt-fetch. automatically returns data to these buffers. This is row-by-row fetching. When statement execution has been completed, close the statement handle using *Note `mysql_stmt_close()': mysql-stmt-close. so that all resources associated with it can be freed. If you obtained a *Note `SELECT': select. statement's result set metadata by calling *Note `mysql_stmt_result_metadata()': mysql-stmt-result-metadata, you should also free the metadata using *Note `mysql_free_result()': mysql-free-result. * Execution Steps * To prepare and execute a statement, an application follows these steps: 1. Create a prepared statement handle with *Note `mysql_stmt_init()': mysql-stmt-init. To prepare the statement on the server, call *Note `mysql_stmt_prepare()': mysql-stmt-prepare. and pass it a string containing the SQL statement. 2. If the statement will produce a result set, call *Note `mysql_stmt_result_metadata()': mysql-stmt-result-metadata. to obtain the result set metadata. This metadata is itself in the form of result set, albeit a separate one from the one that contains the rows returned by the query. The metadata result set indicates how many columns are in the result and contains information about each column. 3. Set the values of any parameters using *Note `mysql_stmt_bind_param()': mysql-stmt-bind-param. All parameters must be set. Otherwise, statement execution returns an error or produces unexpected results. 4. Call *Note `mysql_stmt_execute()': mysql-stmt-execute. to execute the statement. 5. If the statement produces a result set, bind the data buffers to use for retrieving the row values by calling *Note `mysql_stmt_bind_result()': mysql-stmt-bind-result. 6. Fetch the data into the buffers row by row by calling *Note `mysql_stmt_fetch()': mysql-stmt-fetch. repeatedly until no more rows are found. 7. Repeat steps 3 through 6 as necessary, by changing the parameter values and re-executing the statement. When *Note `mysql_stmt_prepare()': mysql-stmt-prepare. is called, the MySQL client/server protocol performs these actions: * The server parses the statement and sends the okay status back to the client by assigning a statement ID. It also sends total number of parameters, a column count, and its metadata if it is a result set oriented statement. All syntax and semantics of the statement are checked by the server during this call. * The client uses this statement ID for the further operations, so that the server can identify the statement from among its pool of statements. When *Note `mysql_stmt_execute()': mysql-stmt-execute. is called, the MySQL client/server protocol performs these actions: * The client uses the statement handle and sends the parameter data to the server. * The server identifies the statement using the ID provided by the client, replaces the parameter markers with the newly supplied data, and executes the statement. If the statement produces a result set, the server sends the data back to the client. Otherwise, it sends an okay status and the number of rows changed, deleted, or inserted. When *Note `mysql_stmt_fetch()': mysql-stmt-fetch. is called, the MySQL client/server protocol performs these actions: * The client reads the data from the current row of the result set and places it into the application data buffers by doing the necessary conversions. If the application buffer type is same as that of the field type returned from the server, the conversions are straightforward. If an error occurs, you can get the statement error number, error message, and SQLSTATE code using *Note `mysql_stmt_errno()': mysql-stmt-errno, *Note `mysql_stmt_error()': mysql-stmt-error, and *Note `mysql_stmt_sqlstate()': mysql-stmt-sqlstate, respectively. * Prepared Statement Logging * For prepared statements that are executed with the *Note `mysql_stmt_prepare()': mysql-stmt-prepare. and *Note `mysql_stmt_execute()': mysql-stmt-execute. C API functions, the server writes `Prepare' and `Execute' lines to the general query log so that you can tell when statements are prepared and executed. Suppose that you prepare and execute a statement as follows: 1. Call *Note `mysql_stmt_prepare()': mysql-stmt-prepare. to prepare the statement string `"SELECT ?"'. 2. Call *Note `mysql_stmt_bind_param()': mysql-stmt-bind-param. to bind the value `3' to the parameter in the prepared statement. 3. Call *Note `mysql_stmt_execute()': mysql-stmt-execute. to execute the prepared statement. As a result of the preceding calls, the server writes the following lines to the general query log: Prepare [1] SELECT ? Execute [1] SELECT 3 Each `Prepare' and `Execute' line in the log is tagged with a `[N]' statement identifier so that you can keep track of which prepared statement is being logged. N is a positive integer. If there are multiple prepared statements active simultaneously for the client, N may be greater than 1. Each `Execute' lines shows a prepared statement after substitution of data values for `?' parameters.  File: manual.info, Node: c-api-prepared-statement-functions, Next: c-api-thread-functions, Prev: c-api-prepared-statement-function-overview, Up: c 21.9.7 C API Prepared Statement Function Descriptions ----------------------------------------------------- * Menu: * mysql-stmt-affected-rows:: `mysql_stmt_affected_rows()' * mysql-stmt-attr-get:: `mysql_stmt_attr_get()' * mysql-stmt-attr-set:: `mysql_stmt_attr_set()' * mysql-stmt-bind-param:: `mysql_stmt_bind_param()' * mysql-stmt-bind-result:: `mysql_stmt_bind_result()' * mysql-stmt-close:: `mysql_stmt_close()' * mysql-stmt-data-seek:: `mysql_stmt_data_seek()' * mysql-stmt-errno:: `mysql_stmt_errno()' * mysql-stmt-error:: `mysql_stmt_error()' * mysql-stmt-execute:: `mysql_stmt_execute()' * mysql-stmt-fetch:: `mysql_stmt_fetch()' * mysql-stmt-fetch-column:: `mysql_stmt_fetch_column()' * mysql-stmt-field-count:: `mysql_stmt_field_count()' * mysql-stmt-free-result:: `mysql_stmt_free_result()' * mysql-stmt-init:: `mysql_stmt_init()' * mysql-stmt-insert-id:: `mysql_stmt_insert_id()' * mysql-stmt-num-rows:: `mysql_stmt_num_rows()' * mysql-stmt-param-count:: `mysql_stmt_param_count()' * mysql-stmt-param-metadata:: `mysql_stmt_param_metadata()' * mysql-stmt-prepare:: `mysql_stmt_prepare()' * mysql-stmt-reset:: `mysql_stmt_reset()' * mysql-stmt-result-metadata:: `mysql_stmt_result_metadata()' * mysql-stmt-row-seek:: `mysql_stmt_row_seek()' * mysql-stmt-row-tell:: `mysql_stmt_row_tell()' * mysql-stmt-send-long-data:: `mysql_stmt_send_long_data()' * mysql-stmt-sqlstate:: `mysql_stmt_sqlstate()' * mysql-stmt-store-result:: `mysql_stmt_store_result()' To prepare and execute queries, use the functions described in detail in the following sections. All functions that operate with a `MYSQL_STMT' structure begin with the prefix `mysql_stmt_'. To create a `MYSQL_STMT' handle, use the *Note `mysql_stmt_init()': mysql-stmt-init. function.  File: manual.info, Node: mysql-stmt-affected-rows, Next: mysql-stmt-attr-get, Prev: c-api-prepared-statement-functions, Up: c-api-prepared-statement-functions 21.9.7.1 `mysql_stmt_affected_rows()' ..................................... `my_ulonglong mysql_stmt_affected_rows(MYSQL_STMT *stmt)' * Description * *Note `mysql_stmt_affected_rows()': mysql-stmt-affected-rows. may be called immediately after executing a statement with *Note `mysql_stmt_execute()': mysql-stmt-execute. It is like *Note `mysql_affected_rows()': mysql-affected-rows. but for prepared statements. For a description of what the affected-rows value returned by this function means, See *Note mysql-affected-rows::. * Errors * None. * Example * See the Example in *Note mysql-stmt-execute::.  File: manual.info, Node: mysql-stmt-attr-get, Next: mysql-stmt-attr-set, Prev: mysql-stmt-affected-rows, Up: c-api-prepared-statement-functions 21.9.7.2 `mysql_stmt_attr_get()' ................................ `my_bool mysql_stmt_attr_get(MYSQL_STMT *stmt, enum enum_stmt_attr_type option, void *arg)' * Description * Can be used to get the current value for a statement attribute. The `option' argument is the option that you want to get; the `arg' should point to a variable that should contain the option value. If the option is an integer, `arg' should point to the value of the integer. See *Note mysql-stmt-attr-set::, for a list of options and option types. *Note*: In MySQL 5.1, *Note `mysql_stmt_attr_get()': mysql-stmt-attr-get. originally used `unsigned int *', not `my_bool *', for `STMT_ATTR_UPDATE_MAX_LENGTH'. This was corrected in MySQL 5.1.7. * Return Values * Zero if successful. Nonzero if `option' is unknown. * Errors * None.  File: manual.info, Node: mysql-stmt-attr-set, Next: mysql-stmt-bind-param, Prev: mysql-stmt-attr-get, Up: c-api-prepared-statement-functions 21.9.7.3 `mysql_stmt_attr_set()' ................................ `my_bool mysql_stmt_attr_set(MYSQL_STMT *stmt, enum enum_stmt_attr_type option, const void *arg)' * Description * Can be used to affect behavior for a prepared statement. This function may be called multiple times to set several options. The `option' argument is the option that you want to set. The `arg' argument is the value for the option. `arg' should point to a variable that is set to the desired attribute value. The variable type is as indicated in the following table. The following table shows the possible `option' values. Option Argument Type Function `STMT_ATTR_UPDATE_MAX_LENGTH' `my_bool *' If set to 1, causes *Note `mysql_stmt_store_result()': mysql-stmt-store-result. to update the metadata `MYSQL_FIELD->max_length' value. `STMT_ATTR_CURSOR_TYPE' `unsigned Type of cursor to open for long *' statement when *Note `mysql_stmt_execute()': mysql-stmt-execute. is invoked. `*arg' can be `CURSOR_TYPE_NO_CURSOR' (the default) or `CURSOR_TYPE_READ_ONLY'. `STMT_ATTR_PREFETCH_ROWS' `unsigned Number of rows to fetch long *' from server at a time when using a cursor. `*arg' can be in the range from 1 to the maximum value of `unsigned long'. The default is 1. If you use the `STMT_ATTR_CURSOR_TYPE' option with `CURSOR_TYPE_READ_ONLY', a cursor is opened for the statement when you invoke *Note `mysql_stmt_execute()': mysql-stmt-execute. If there is already an open cursor from a previous *Note `mysql_stmt_execute()': mysql-stmt-execute. call, it closes the cursor before opening a new one. *Note `mysql_stmt_reset()': mysql-stmt-reset. also closes any open cursor before preparing the statement for re-execution. *Note `mysql_stmt_free_result()': mysql-stmt-free-result. closes any open cursor. If you open a cursor for a prepared statement, *Note `mysql_stmt_store_result()': mysql-stmt-store-result. is unnecessary, because that function causes the result set to be buffered on the client side. * Return Values * Zero if successful. Nonzero if `option' is unknown. * Errors * None. * Example * The following example opens a cursor for a prepared statement and sets the number of rows to fetch at a time to 5: MYSQL_STMT *stmt; int rc; unsigned long type; unsigned long prefetch_rows = 5; stmt = mysql_stmt_init(mysql); type = (unsigned long) CURSOR_TYPE_READ_ONLY; rc = mysql_stmt_attr_set(stmt, STMT_ATTR_CURSOR_TYPE, (void*) &type); /* ... check return value ... */ rc = mysql_stmt_attr_set(stmt, STMT_ATTR_PREFETCH_ROWS, (void*) &prefetch_rows); /* ... check return value ... */  File: manual.info, Node: mysql-stmt-bind-param, Next: mysql-stmt-bind-result, Prev: mysql-stmt-attr-set, Up: c-api-prepared-statement-functions 21.9.7.4 `mysql_stmt_bind_param()' .................................. `my_bool mysql_stmt_bind_param(MYSQL_STMT *stmt, MYSQL_BIND *bind)' * Description * *Note `mysql_stmt_bind_param()': mysql-stmt-bind-param. is used to bind input data for the parameter markers in the SQL statement that was passed to *Note `mysql_stmt_prepare()': mysql-stmt-prepare. It uses `MYSQL_BIND' structures to supply the data. `bind' is the address of an array of `MYSQL_BIND' structures. The client library expects the array to contain one element for each ``?'' parameter marker that is present in the query. Suppose that you prepare the following statement: INSERT INTO mytbl VALUES(?,?,?) When you bind the parameters, the array of `MYSQL_BIND' structures must contain three elements, and can be declared like this: MYSQL_BIND bind[3]; *Note c-api-prepared-statement-data-structures::, describes the members of each `MYSQL_BIND' element and how they should be set to provide input values. * Return Values * Zero if the bind operation was successful. Nonzero if an error occurred. * Errors * * `CR_UNSUPPORTED_PARAM_TYPE' The conversion is not supported. Possibly the `buffer_type' value is illegal or is not one of the supported types. * `CR_OUT_OF_MEMORY' Out of memory. * `CR_UNKNOWN_ERROR' An unknown error occurred. * Example * See the Example in *Note mysql-stmt-execute::.  File: manual.info, Node: mysql-stmt-bind-result, Next: mysql-stmt-close, Prev: mysql-stmt-bind-param, Up: c-api-prepared-statement-functions 21.9.7.5 `mysql_stmt_bind_result()' ................................... `my_bool mysql_stmt_bind_result(MYSQL_STMT *stmt, MYSQL_BIND *bind)' * Description * *Note `mysql_stmt_bind_result()': mysql-stmt-bind-result. is used to associate (that is, bind) output columns in the result set to data buffers and length buffers. When *Note `mysql_stmt_fetch()': mysql-stmt-fetch. is called to fetch data, the MySQL client/server protocol places the data for the bound columns into the specified buffers. All columns must be bound to buffers prior to calling *Note `mysql_stmt_fetch()': mysql-stmt-fetch. `bind' is the address of an array of `MYSQL_BIND' structures. The client library expects the array to contain one element for each column of the result set. If you do not bind columns to `MYSQL_BIND' structures, *Note `mysql_stmt_fetch()': mysql-stmt-fetch. simply ignores the data fetch. The buffers should be large enough to hold the data values, because the protocol doesn't return data values in chunks. A column can be bound or rebound at any time, even after a result set has been partially retrieved. The new binding takes effect the next time *Note `mysql_stmt_fetch()': mysql-stmt-fetch. is called. Suppose that an application binds the columns in a result set and calls *Note `mysql_stmt_fetch()': mysql-stmt-fetch. The client/server protocol returns data in the bound buffers. Then suppose that the application binds the columns to a different set of buffers. The protocol places data into the newly bound buffers when the next call to *Note `mysql_stmt_fetch()': mysql-stmt-fetch. occurs. To bind a column, an application calls *Note `mysql_stmt_bind_result()': mysql-stmt-bind-result. and passes the type, address, and length of the output buffer into which the value should be stored. *Note c-api-prepared-statement-data-structures::, describes the members of each `MYSQL_BIND' element and how they should be set to receive output values. * Return Values * Zero if the bind operation was successful. Nonzero if an error occurred. * Errors * * `CR_UNSUPPORTED_PARAM_TYPE' The conversion is not supported. Possibly the `buffer_type' value is illegal or is not one of the supported types. * `CR_OUT_OF_MEMORY' Out of memory. * `CR_UNKNOWN_ERROR' An unknown error occurred. * Example * See the Example in *Note mysql-stmt-fetch::.  File: manual.info, Node: mysql-stmt-close, Next: mysql-stmt-data-seek, Prev: mysql-stmt-bind-result, Up: c-api-prepared-statement-functions 21.9.7.6 `mysql_stmt_close()' ............................. `my_bool mysql_stmt_close(MYSQL_STMT *)' * Description * Closes the prepared statement. *Note `mysql_stmt_close()': mysql-stmt-close. also deallocates the statement handle pointed to by `stmt'. If the current statement has pending or unread results, this function cancels them so that the next query can be executed. * Return Values * Zero if the statement was freed successfully. Nonzero if an error occurred. * Errors * * `CR_SERVER_GONE_ERROR' The MySQL server has gone away. * `CR_UNKNOWN_ERROR' An unknown error occurred. * Example * See the Example in *Note mysql-stmt-execute::.  File: manual.info, Node: mysql-stmt-data-seek, Next: mysql-stmt-errno, Prev: mysql-stmt-close, Up: c-api-prepared-statement-functions 21.9.7.7 `mysql_stmt_data_seek()' ................................. `void mysql_stmt_data_seek(MYSQL_STMT *stmt, my_ulonglong offset)' * Description * Seeks to an arbitrary row in a statement result set. The `offset' value is a row number and should be in the range from `0' to *Note `mysql_stmt_num_rows(stmt)-1': mysql-stmt-num-rows. This function requires that the statement result set structure contains the entire result of the last executed query, so *Note `mysql_stmt_data_seek()': mysql-stmt-data-seek. may be used only in conjunction with *Note `mysql_stmt_store_result()': mysql-stmt-store-result. * Return Values * None. * Errors * None.  File: manual.info, Node: mysql-stmt-errno, Next: mysql-stmt-error, Prev: mysql-stmt-data-seek, Up: c-api-prepared-statement-functions 21.9.7.8 `mysql_stmt_errno()' ............................. `unsigned int mysql_stmt_errno(MYSQL_STMT *stmt)' * Description * For the statement specified by `stmt', *Note `mysql_stmt_errno()': mysql-stmt-errno. returns the error code for the most recently invoked statement API function that can succeed or fail. A return value of zero means that no error occurred. Client error message numbers are listed in the MySQL `errmsg.h' header file. Server error message numbers are listed in `mysqld_error.h'. Errors also are listed at *Note error-handling::. * Return Values * An error code value. Zero if no error occurred. * Errors * None.  File: manual.info, Node: mysql-stmt-error, Next: mysql-stmt-execute, Prev: mysql-stmt-errno, Up: c-api-prepared-statement-functions 21.9.7.9 `mysql_stmt_error()' ............................. `const char *mysql_stmt_error(MYSQL_STMT *stmt)' * Description * For the statement specified by `stmt', *Note `mysql_stmt_error()': mysql-stmt-error. returns a null-terminated string containing the error message for the most recently invoked statement API function that can succeed or fail. An empty string (`""') is returned if no error occurred. This means the following two tests are equivalent: if(*mysql_stmt_errno(stmt)) { // an error occurred } if (mysql_stmt_error(stmt)[0]) { // an error occurred } The language of the client error messages may be changed by recompiling the MySQL client library. Currently, you can choose error messages in several different languages. * Return Values * A character string that describes the error. An empty string if no error occurred. * Errors * None.  File: manual.info, Node: mysql-stmt-execute, Next: mysql-stmt-fetch, Prev: mysql-stmt-error, Up: c-api-prepared-statement-functions 21.9.7.10 `mysql_stmt_execute()' ................................ `int mysql_stmt_execute(MYSQL_STMT *stmt)' * Description * *Note `mysql_stmt_execute()': mysql-stmt-execute. executes the prepared query associated with the statement handle. The currently bound parameter marker values are sent to server during this call, and the server replaces the markers with this newly supplied data. Statement processing following *Note `mysql_stmt_execute()': mysql-stmt-execute. depends on the type of statement: * For an *Note `UPDATE': update, *Note `DELETE': delete, or *Note `INSERT': insert, the number of changed, deleted, or inserted rows can be found by calling *Note `mysql_stmt_affected_rows()': mysql-stmt-affected-rows. * For a statement such as *Note `SELECT': select. that generates a result set, you must call *Note `mysql_stmt_fetch()': mysql-stmt-fetch. to fetch the data prior to calling any other functions that result in query processing. For more information on how to fetch the results, refer to *Note mysql-stmt-fetch::. Do not following invocation of *Note `mysql_stmt_execute()': mysql-stmt-execute. with a call to *Note `mysql_store_result()': mysql-store-result. or *Note `mysql_use_result()': mysql-use-result. Those functions are not intended for processing results from prepared statements. For statements that generate a result set, you can request that *Note `mysql_stmt_execute()': mysql-stmt-execute. open a cursor for the statement by calling *Note `mysql_stmt_attr_set()': mysql-stmt-attr-set. before executing the statement. If you execute a statement multiple times, *Note `mysql_stmt_execute()': mysql-stmt-execute. closes any open cursor before opening a new one. As of MySQL 5.1.25, metadata changes to tables or views referred to by prepared statements are detected and cause automatic repreparation of the statement when it is next executed. For more information, see *Note statement-repreparation::. * Return Values * Zero if execution was successful. Nonzero if an error occurred. * Errors * * `CR_COMMANDS_OUT_OF_SYNC' Commands were executed in an improper order. * `CR_OUT_OF_MEMORY' Out of memory. * `CR_SERVER_GONE_ERROR' The MySQL server has gone away. * `CR_SERVER_LOST' The connection to the server was lost during the query. * `CR_UNKNOWN_ERROR' An unknown error occurred. * Example * The following example demonstrates how to create and populate a table using *Note `mysql_stmt_init()': mysql-stmt-init, *Note `mysql_stmt_prepare()': mysql-stmt-prepare, *Note `mysql_stmt_param_count()': mysql-stmt-param-count, *Note `mysql_stmt_bind_param()': mysql-stmt-bind-param, *Note `mysql_stmt_execute()': mysql-stmt-execute, and *Note `mysql_stmt_affected_rows()': mysql-stmt-affected-rows. The `mysql' variable is assumed to be a valid connection handle. For an example that shows how to retrieve data, see *Note mysql-stmt-fetch::. #define STRING_SIZE 50 #define DROP_SAMPLE_TABLE "DROP TABLE IF EXISTS test_table" #define CREATE_SAMPLE_TABLE "CREATE TABLE test_table(col1 INT,\ col2 VARCHAR(40),\ col3 SMALLINT,\ col4 TIMESTAMP)" #define INSERT_SAMPLE "INSERT INTO \ test_table(col1,col2,col3) \ VALUES(?,?,?)" MYSQL_STMT *stmt; MYSQL_BIND bind[3]; my_ulonglong affected_rows; int param_count; short small_data; int int_data; char str_data[STRING_SIZE]; unsigned long str_length; my_bool is_null; if (mysql_query(mysql, DROP_SAMPLE_TABLE)) { fprintf(stderr, " DROP TABLE failed\n"); fprintf(stderr, " %s\n", mysql_error(mysql)); exit(0); } if (mysql_query(mysql, CREATE_SAMPLE_TABLE)) { fprintf(stderr, " CREATE TABLE failed\n"); fprintf(stderr, " %s\n", mysql_error(mysql)); exit(0); } /* Prepare an INSERT query with 3 parameters */ /* (the TIMESTAMP column is not named; the server */ /* sets it to the current date and time) */ stmt = mysql_stmt_init(mysql); if (!stmt) { fprintf(stderr, " mysql_stmt_init(), out of memory\n"); exit(0); } if (mysql_stmt_prepare(stmt, INSERT_SAMPLE, strlen(INSERT_SAMPLE))) { fprintf(stderr, " mysql_stmt_prepare(), INSERT failed\n"); fprintf(stderr, " %s\n", mysql_stmt_error(stmt)); exit(0); } fprintf(stdout, " prepare, INSERT successful\n"); /* Get the parameter count from the statement */ param_count= mysql_stmt_param_count(stmt); fprintf(stdout, " total parameters in INSERT: %d\n", param_count); if (param_count != 3) /* validate parameter count */ { fprintf(stderr, " invalid parameter count returned by MySQL\n"); exit(0); } /* Bind the data for all 3 parameters */ memset(bind, 0, sizeof(bind)); /* INTEGER PARAM */ /* This is a number type, so there is no need to specify buffer_length */ bind[0].buffer_type= MYSQL_TYPE_LONG; bind[0].buffer= (char *)&int_data; bind[0].is_null= 0; bind[0].length= 0; /* STRING PARAM */ bind[1].buffer_type= MYSQL_TYPE_STRING; bind[1].buffer= (char *)str_data; bind[1].buffer_length= STRING_SIZE; bind[1].is_null= 0; bind[1].length= &str_length; /* SMALLINT PARAM */ bind[2].buffer_type= MYSQL_TYPE_SHORT; bind[2].buffer= (char *)&small_data; bind[2].is_null= &is_null; bind[2].length= 0; /* Bind the buffers */ if (mysql_stmt_bind_param(stmt, bind)) { fprintf(stderr, " mysql_stmt_bind_param() failed\n"); fprintf(stderr, " %s\n", mysql_stmt_error(stmt)); exit(0); } /* Specify the data values for the first row */ int_data= 10; /* integer */ strncpy(str_data, "MySQL", STRING_SIZE); /* string */ str_length= strlen(str_data); /* INSERT SMALLINT data as NULL */ is_null= 1; /* Execute the INSERT statement - 1*/ if (mysql_stmt_execute(stmt)) { fprintf(stderr, " mysql_stmt_execute(), 1 failed\n"); fprintf(stderr, " %s\n", mysql_stmt_error(stmt)); exit(0); } /* Get the number of affected rows */ affected_rows= mysql_stmt_affected_rows(stmt); fprintf(stdout, " total affected rows(insert 1): %lu\n", (unsigned long) affected_rows); if (affected_rows != 1) /* validate affected rows */ { fprintf(stderr, " invalid affected rows by MySQL\n"); exit(0); } /* Specify data values for second row, then re-execute the statement */ int_data= 1000; strncpy(str_data, " The most popular Open Source database", STRING_SIZE); str_length= strlen(str_data); small_data= 1000; /* smallint */ is_null= 0; /* reset */ /* Execute the INSERT statement - 2*/ if (mysql_stmt_execute(stmt)) { fprintf(stderr, " mysql_stmt_execute, 2 failed\n"); fprintf(stderr, " %s\n", mysql_stmt_error(stmt)); exit(0); } /* Get the total rows affected */ affected_rows= mysql_stmt_affected_rows(stmt); fprintf(stdout, " total affected rows(insert 2): %lu\n", (unsigned long) affected_rows); if (affected_rows != 1) /* validate affected rows */ { fprintf(stderr, " invalid affected rows by MySQL\n"); exit(0); } /* Close the statement */ if (mysql_stmt_close(stmt)) { fprintf(stderr, " failed while closing the statement\n"); fprintf(stderr, " %s\n", mysql_stmt_error(stmt)); exit(0); } *Note*: For complete examples on the use of prepared statement functions, refer to the file `tests/mysql_client_test.c'. This file can be obtained from a MySQL source distribution or from the Bazaar source repository.  File: manual.info, Node: mysql-stmt-fetch, Next: mysql-stmt-fetch-column, Prev: mysql-stmt-execute, Up: c-api-prepared-statement-functions 21.9.7.11 `mysql_stmt_fetch()' .............................. `int mysql_stmt_fetch(MYSQL_STMT *stmt)' * Description * *Note `mysql_stmt_fetch()': mysql-stmt-fetch. returns the next row in the result set. It can be called only while the result set exists; that is, after a call to *Note `mysql_stmt_execute()': mysql-stmt-execute. for a statement such as *Note `SELECT': select. that produces a result set. *Note `mysql_stmt_fetch()': mysql-stmt-fetch. returns row data using the buffers bound by *Note `mysql_stmt_bind_result()': mysql-stmt-bind-result. It returns the data in those buffers for all the columns in the current row set and the lengths are returned to the `length' pointer. All columns must be bound by the application before it calls *Note `mysql_stmt_fetch()': mysql-stmt-fetch. By default, result sets are fetched unbuffered a row at a time from the server. To buffer the entire result set on the client, call *Note `mysql_stmt_store_result()': mysql-stmt-store-result. after binding the data buffers and before calling *Note `mysql_stmt_fetch()': mysql-stmt-fetch. If a fetched data value is a `NULL' value, the `*is_null' value of the corresponding `MYSQL_BIND' structure contains TRUE (1). Otherwise, the data and its length are returned in the `*buffer' and `*length' elements based on the buffer type specified by the application. Each numeric and temporal type has a fixed length, as listed in the following table. The length of the string types depends on the length of the actual data value, as indicated by `data_length'. Type Length `MYSQL_TYPE_TINY' 1 `MYSQL_TYPE_SHORT' 2 `MYSQL_TYPE_LONG' 4 `MYSQL_TYPE_LONGLONG' 8 `MYSQL_TYPE_FLOAT' 4 `MYSQL_TYPE_DOUBLE' 8 `MYSQL_TYPE_TIME' `sizeof(MYSQL_TIME)' `MYSQL_TYPE_DATE' `sizeof(MYSQL_TIME)' `MYSQL_TYPE_DATETIME' `sizeof(MYSQL_TIME)' `MYSQL_TYPE_STRING' `data length' `MYSQL_TYPE_BLOB' `data_length' In some cases you might want to determine the length of a column value before fetching it with *Note `mysql_stmt_fetch()': mysql-stmt-fetch. For example, the value might be a long string or *Note `BLOB': blob. value for which you want to know how much space must be allocated. To accomplish this, you can use these strategies: * Before invoking *Note `mysql_stmt_fetch()': mysql-stmt-fetch. to retrieve individual rows, pass `STMT_ATTR_UPDATE_MAX_LENGTH' to *Note `mysql_stmt_attr_set()': mysql-stmt-attr-set, then invoke *Note `mysql_stmt_store_result()': mysql-stmt-store-result. to buffer the entire result on the client side. Setting the `STMT_ATTR_UPDATE_MAX_LENGTH' attribute causes the maximal length of column values to be indicated by the `max_length' member of the result set metadata returned by *Note `mysql_stmt_result_metadata()': mysql-stmt-result-metadata. * Invoke *Note `mysql_stmt_fetch()': mysql-stmt-fetch. with a zero-length buffer for the column in question and a pointer in which the real length can be stored. Then use the real length with *Note `mysql_stmt_fetch_column()': mysql-stmt-fetch-column. real_length= 0; bind[0].buffer= 0; bind[0].buffer_length= 0; bind[0].length= &real_length mysql_stmt_bind_result(stmt, bind); mysql_stmt_fetch(stmt); if (real_length > 0) { data= malloc(real_length); bind[0].buffer= data; bind[0].buffer_length= real_length; mysql_stmt_fetch_column(stmt, bind, 0, 0); } * Return Values * Return Value Description 0 Successful, the data has been fetched to application data buffers. 1 Error occurred. Error code and message can be obtained by calling *Note `mysql_stmt_errno()': mysql-stmt-errno. and *Note `mysql_stmt_error()': mysql-stmt-error. `MYSQL_NO_DATA' No more rows/data exists `MYSQL_DATA_TRUNCATED' Data truncation occurred `MYSQL_DATA_TRUNCATED' is returned when truncation reporting is enabled. To determine which column values were truncated when this value is returned, check the `error' members of the `MYSQL_BIND' structures used for fetching values. Truncation reporting is enabled by default, but can be controlled by calling *Note `mysql_options()': mysql-options. with the `MYSQL_REPORT_DATA_TRUNCATION' option. * Errors * * `CR_COMMANDS_OUT_OF_SYNC' Commands were executed in an improper order. * `CR_OUT_OF_MEMORY' Out of memory. * `CR_SERVER_GONE_ERROR' The MySQL server has gone away. * `CR_SERVER_LOST' The connection to the server was lost during the query. * `CR_UNKNOWN_ERROR' An unknown error occurred. * `CR_UNSUPPORTED_PARAM_TYPE' The buffer type is `MYSQL_TYPE_DATE', `MYSQL_TYPE_TIME', `MYSQL_TYPE_DATETIME', or `MYSQL_TYPE_TIMESTAMP', but the data type is not *Note `DATE': datetime, *Note `TIME': time, *Note `DATETIME': datetime, or *Note `TIMESTAMP': datetime. * All other unsupported conversion errors are returned from *Note `mysql_stmt_bind_result()': mysql-stmt-bind-result. * Example * The following example demonstrates how to fetch data from a table using *Note `mysql_stmt_result_metadata()': mysql-stmt-result-metadata, *Note `mysql_stmt_bind_result()': mysql-stmt-bind-result, and *Note `mysql_stmt_fetch()': mysql-stmt-fetch. (This example expects to retrieve the two rows inserted by the example shown in *Note mysql-stmt-execute::.) The `mysql' variable is assumed to be a valid connection handle. #define STRING_SIZE 50 #define SELECT_SAMPLE "SELECT col1, col2, col3, col4 \ FROM test_table" MYSQL_STMT *stmt; MYSQL_BIND bind[4]; MYSQL_RES *prepare_meta_result; MYSQL_TIME ts; unsigned long length[4]; int param_count, column_count, row_count; short small_data; int int_data; char str_data[STRING_SIZE]; my_bool is_null[4]; my_bool error[4]; /* Prepare a SELECT query to fetch data from test_table */ stmt = mysql_stmt_init(mysql); if (!stmt) { fprintf(stderr, " mysql_stmt_init(), out of memory\n"); exit(0); } if (mysql_stmt_prepare(stmt, SELECT_SAMPLE, strlen(SELECT_SAMPLE))) { fprintf(stderr, " mysql_stmt_prepare(), SELECT failed\n"); fprintf(stderr, " %s\n", mysql_stmt_error(stmt)); exit(0); } fprintf(stdout, " prepare, SELECT successful\n"); /* Get the parameter count from the statement */ param_count= mysql_stmt_param_count(stmt); fprintf(stdout, " total parameters in SELECT: %d\n", param_count); if (param_count != 0) /* validate parameter count */ { fprintf(stderr, " invalid parameter count returned by MySQL\n"); exit(0); } /* Fetch result set meta information */ prepare_meta_result = mysql_stmt_result_metadata(stmt); if (!prepare_meta_result) { fprintf(stderr, " mysql_stmt_result_metadata(), \ returned no meta information\n"); fprintf(stderr, " %s\n", mysql_stmt_error(stmt)); exit(0); } /* Get total columns in the query */ column_count= mysql_num_fields(prepare_meta_result); fprintf(stdout, " total columns in SELECT statement: %d\n", column_count); if (column_count != 4) /* validate column count */ { fprintf(stderr, " invalid column count returned by MySQL\n"); exit(0); } /* Execute the SELECT query */ if (mysql_stmt_execute(stmt)) { fprintf(stderr, " mysql_stmt_execute(), failed\n"); fprintf(stderr, " %s\n", mysql_stmt_error(stmt)); exit(0); } /* Bind the result buffers for all 4 columns before fetching them */ memset(bind, 0, sizeof(bind)); /* INTEGER COLUMN */ bind[0].buffer_type= MYSQL_TYPE_LONG; bind[0].buffer= (char *)&int_data; bind[0].is_null= &is_null[0]; bind[0].length= &length[0]; bind[0].error= &error[0]; /* STRING COLUMN */ bind[1].buffer_type= MYSQL_TYPE_STRING; bind[1].buffer= (char *)str_data; bind[1].buffer_length= STRING_SIZE; bind[1].is_null= &is_null[1]; bind[1].length= &length[1]; bind[1].error= &error[1]; /* SMALLINT COLUMN */ bind[2].buffer_type= MYSQL_TYPE_SHORT; bind[2].buffer= (char *)&small_data; bind[2].is_null= &is_null[2]; bind[2].length= &length[2]; bind[2].error= &error[2]; /* TIMESTAMP COLUMN */ bind[3].buffer_type= MYSQL_TYPE_TIMESTAMP; bind[3].buffer= (char *)&ts; bind[3].is_null= &is_null[3]; bind[3].length= &length[3]; bind[3].error= &error[3]; /* Bind the result buffers */ if (mysql_stmt_bind_result(stmt, bind)) { fprintf(stderr, " mysql_stmt_bind_result() failed\n"); fprintf(stderr, " %s\n", mysql_stmt_error(stmt)); exit(0); } /* Now buffer all results to client (optional step) */ if (mysql_stmt_store_result(stmt)) { fprintf(stderr, " mysql_stmt_store_result() failed\n"); fprintf(stderr, " %s\n", mysql_stmt_error(stmt)); exit(0); } /* Fetch all rows */ row_count= 0; fprintf(stdout, "Fetching results ...\n"); while (!mysql_stmt_fetch(stmt)) { row_count++; fprintf(stdout, " row %d\n", row_count); /* column 1 */ fprintf(stdout, " column1 (integer) : "); if (is_null[0]) fprintf(stdout, " NULL\n"); else fprintf(stdout, " %d(%ld)\n", int_data, length[0]); /* column 2 */ fprintf(stdout, " column2 (string) : "); if (is_null[1]) fprintf(stdout, " NULL\n"); else fprintf(stdout, " %s(%ld)\n", str_data, length[1]); /* column 3 */ fprintf(stdout, " column3 (smallint) : "); if (is_null[2]) fprintf(stdout, " NULL\n"); else fprintf(stdout, " %d(%ld)\n", small_data, length[2]); /* column 4 */ fprintf(stdout, " column4 (timestamp): "); if (is_null[3]) fprintf(stdout, " NULL\n"); else fprintf(stdout, " %04d-%02d-%02d %02d:%02d:%02d (%ld)\n", ts.year, ts.month, ts.day, ts.hour, ts.minute, ts.second, length[3]); fprintf(stdout, "\n"); } /* Validate rows fetched */ fprintf(stdout, " total rows fetched: %d\n", row_count); if (row_count != 2) { fprintf(stderr, " MySQL failed to return all rows\n"); exit(0); } /* Free the prepared result metadata */ mysql_free_result(prepare_meta_result); /* Close the statement */ if (mysql_stmt_close(stmt)) { fprintf(stderr, " failed while closing the statement\n"); fprintf(stderr, " %s\n", mysql_stmt_error(stmt)); exit(0); }  File: manual.info, Node: mysql-stmt-fetch-column, Next: mysql-stmt-field-count, Prev: mysql-stmt-fetch, Up: c-api-prepared-statement-functions 21.9.7.12 `mysql_stmt_fetch_column()' ..................................... `int mysql_stmt_fetch_column(MYSQL_STMT *stmt, MYSQL_BIND *bind, unsigned int column, unsigned long offset)' * Description * Fetch one column from the current result set row. `bind' provides the buffer where data should be placed. It should be set up the same way as for *Note `mysql_stmt_bind_result()': mysql-stmt-bind-result. `column' indicates which column to fetch. The first column is numbered 0. `offset' is the offset within the data value at which to begin retrieving data. This can be used for fetching the data value in pieces. The beginning of the value is offset 0. * Return Values * Zero if the value was fetched successfully. Nonzero if an error occurred. * Errors * * `CR_INVALID_PARAMETER_NO' Invalid column number. * `CR_NO_DATA' The end of the result set has already been reached.  File: manual.info, Node: mysql-stmt-field-count, Next: mysql-stmt-free-result, Prev: mysql-stmt-fetch-column, Up: c-api-prepared-statement-functions 21.9.7.13 `mysql_stmt_field_count()' .................................... `unsigned int mysql_stmt_field_count(MYSQL_STMT *stmt)' * Description * Returns the number of columns for the most recent statement for the statement handler. This value is zero for statements such as *Note `INSERT': insert. or *Note `DELETE': delete. that do not produce result sets. *Note `mysql_stmt_field_count()': mysql-stmt-field-count. can be called after you have prepared a statement by invoking *Note `mysql_stmt_prepare()': mysql-stmt-prepare. * Return Values * An unsigned integer representing the number of columns in a result set. * Errors * None.  File: manual.info, Node: mysql-stmt-free-result, Next: mysql-stmt-init, Prev: mysql-stmt-field-count, Up: c-api-prepared-statement-functions 21.9.7.14 `mysql_stmt_free_result()' .................................... `my_bool mysql_stmt_free_result(MYSQL_STMT *stmt)' * Description * Releases memory associated with the result set produced by execution of the prepared statement. If there is a cursor open for the statement, *Note `mysql_stmt_free_result()': mysql-stmt-free-result. closes it. * Return Values * Zero if the result set was freed successfully. Nonzero if an error occurred. * Errors *  File: manual.info, Node: mysql-stmt-init, Next: mysql-stmt-insert-id, Prev: mysql-stmt-free-result, Up: c-api-prepared-statement-functions 21.9.7.15 `mysql_stmt_init()' ............................. `MYSQL_STMT *mysql_stmt_init(MYSQL *mysql)' * Description * Create a `MYSQL_STMT' handle. The handle should be freed with *Note `mysql_stmt_close(MYSQL_STMT *)': mysql-stmt-close. See also *Note c-api-prepared-statement-data-structures::, for more information. * Return Values * A pointer to a `MYSQL_STMT' structure in case of success. `NULL' if out of memory. * Errors * * `CR_OUT_OF_MEMORY' Out of memory.  File: manual.info, Node: mysql-stmt-insert-id, Next: mysql-stmt-num-rows, Prev: mysql-stmt-init, Up: c-api-prepared-statement-functions 21.9.7.16 `mysql_stmt_insert_id()' .................................. `my_ulonglong mysql_stmt_insert_id(MYSQL_STMT *stmt)' * Description * Returns the value generated for an `AUTO_INCREMENT' column by the prepared *Note `INSERT': insert. or *Note `UPDATE': update. statement. Use this function after you have executed a prepared *Note `INSERT': insert. statement on a table which contains an `AUTO_INCREMENT' field. See *Note mysql-insert-id::, for more information. * Return Values * Value for `AUTO_INCREMENT' column which was automatically generated or explicitly set during execution of prepared statement, or value generated by `LAST_INSERT_ID(EXPR)' function. Return value is undefined if statement does not set `AUTO_INCREMENT' value. * Errors * None.  File: manual.info, Node: mysql-stmt-num-rows, Next: mysql-stmt-param-count, Prev: mysql-stmt-insert-id, Up: c-api-prepared-statement-functions 21.9.7.17 `mysql_stmt_num_rows()' ................................. `my_ulonglong mysql_stmt_num_rows(MYSQL_STMT *stmt)' * Description * Returns the number of rows in the result set. The use of *Note `mysql_stmt_num_rows()': mysql-stmt-num-rows. depends on whether you used *Note `mysql_stmt_store_result()': mysql-stmt-store-result. to buffer the entire result set in the statement handle. If you use *Note `mysql_stmt_store_result()': mysql-stmt-store-result, *Note `mysql_stmt_num_rows()': mysql-stmt-num-rows. may be called immediately. Otherwise, the row count is unavailable unless you count the rows as you fetch them. *Note `mysql_stmt_num_rows()': mysql-stmt-num-rows. is intended for use with statements that return a result set, such as *Note `SELECT': select. For statements such as *Note `INSERT': insert, *Note `UPDATE': update, or *Note `DELETE': delete, the number of affected rows can be obtained with *Note `mysql_stmt_affected_rows()': mysql-stmt-affected-rows. * Return Values * The number of rows in the result set. * Errors * None.  File: manual.info, Node: mysql-stmt-param-count, Next: mysql-stmt-param-metadata, Prev: mysql-stmt-num-rows, Up: c-api-prepared-statement-functions 21.9.7.18 `mysql_stmt_param_count()' .................................... `unsigned long mysql_stmt_param_count(MYSQL_STMT *stmt)' * Description * Returns the number of parameter markers present in the prepared statement. * Return Values * An unsigned long integer representing the number of parameters in a statement. * Errors * None. * Example * See the Example in *Note mysql-stmt-execute::.  File: manual.info, Node: mysql-stmt-param-metadata, Next: mysql-stmt-prepare, Prev: mysql-stmt-param-count, Up: c-api-prepared-statement-functions 21.9.7.19 `mysql_stmt_param_metadata()' ....................................... `MYSQL_RES *mysql_stmt_param_metadata(MYSQL_STMT *stmt)' This function currently does nothing. * Description * * Return Values * * Errors *  File: manual.info, Node: mysql-stmt-prepare, Next: mysql-stmt-reset, Prev: mysql-stmt-param-metadata, Up: c-api-prepared-statement-functions 21.9.7.20 `mysql_stmt_prepare()' ................................ `int mysql_stmt_prepare(MYSQL_STMT *stmt, const char *stmt_str, unsigned long length)' * Description * Given the statement handle returned by *Note `mysql_stmt_init()': mysql-stmt-init, prepares the SQL statement pointed to by the string `stmt_str' and returns a status value. The string length should be given by the `length' argument. The string must consist of a single SQL statement. You should not add a terminating semicolon (``;'') or `\g' to the statement. The application can include one or more parameter markers in the SQL statement by embedding question mark (``?'') characters into the SQL string at the appropriate positions. The markers are legal only in certain places in SQL statements. For example, they are permitted in the `VALUES()' list of an *Note `INSERT': insert. statement (to specify column values for a row), or in a comparison with a column in a `WHERE' clause to specify a comparison value. However, they are not permitted for identifiers (such as table or column names), or to specify both operands of a binary operator such as the `=' equal sign. The latter restriction is necessary because it would be impossible to determine the parameter type. In general, parameters are legal only in Data Manipulation Language (DML) statements, and not in Data Definition Language (DDL) statements. The parameter markers must be bound to application variables using *Note `mysql_stmt_bind_param()': mysql-stmt-bind-param. before executing the statement. * Return Values * Zero if the statement was prepared successfully. Nonzero if an error occurred. * Errors * * `CR_COMMANDS_OUT_OF_SYNC' Commands were executed in an improper order. * `CR_OUT_OF_MEMORY' Out of memory. * `CR_SERVER_GONE_ERROR' The MySQL server has gone away. * `CR_SERVER_LOST' The connection to the server was lost during the query * `CR_UNKNOWN_ERROR' An unknown error occurred. If the prepare operation was unsuccessful (that is, *Note `mysql_stmt_prepare()': mysql-stmt-prepare. returns nonzero), the error message can be obtained by calling *Note `mysql_stmt_error()': mysql-stmt-error. * Example * See the Example in *Note mysql-stmt-execute::.  File: manual.info, Node: mysql-stmt-reset, Next: mysql-stmt-result-metadata, Prev: mysql-stmt-prepare, Up: c-api-prepared-statement-functions 21.9.7.21 `mysql_stmt_reset()' .............................. `my_bool mysql_stmt_reset(MYSQL_STMT *stmt)' * Description * Resets a prepared statement on client and server to state after prepare. It resets the statement on the server, data sent using *Note `mysql_stmt_send_long_data()': mysql-stmt-send-long-data, unbuffered result sets and current errors. It does not clear bindings or stored result sets. Stored result sets will be cleared when executing the prepared statement (or closing it). To re-prepare the statement with another query, use *Note `mysql_stmt_prepare()': mysql-stmt-prepare. * Return Values * Zero if the statement was reset successfully. Nonzero if an error occurred. * Errors * * `CR_COMMANDS_OUT_OF_SYNC' Commands were executed in an improper order. * `CR_SERVER_GONE_ERROR' The MySQL server has gone away. * `CR_SERVER_LOST' The connection to the server was lost during the query * `CR_UNKNOWN_ERROR' An unknown error occurred.  File: manual.info, Node: mysql-stmt-result-metadata, Next: mysql-stmt-row-seek, Prev: mysql-stmt-reset, Up: c-api-prepared-statement-functions 21.9.7.22 `mysql_stmt_result_metadata()' ........................................ `MYSQL_RES *mysql_stmt_result_metadata(MYSQL_STMT *stmt)' * Description * If a statement passed to *Note `mysql_stmt_prepare()': mysql-stmt-prepare. is one that produces a result set, *Note `mysql_stmt_result_metadata()': mysql-stmt-result-metadata. returns the result set metadata in the form of a pointer to a `MYSQL_RES' structure that can be used to process the meta information such as number of fields and individual field information. This result set pointer can be passed as an argument to any of the field-based API functions that process result set metadata, such as: * *Note `mysql_num_fields()': mysql-num-fields. * *Note `mysql_fetch_field()': mysql-fetch-field. * *Note `mysql_fetch_field_direct()': mysql-fetch-field-direct. * *Note `mysql_fetch_fields()': mysql-fetch-fields. * *Note `mysql_field_count()': mysql-field-count. * *Note `mysql_field_seek()': mysql-field-seek. * *Note `mysql_field_tell()': mysql-field-tell. * *Note `mysql_free_result()': mysql-free-result. The result set structure should be freed when you are done with it, which you can do by passing it to *Note `mysql_free_result()': mysql-free-result. This is similar to the way you free a result set obtained from a call to *Note `mysql_store_result()': mysql-store-result. The result set returned by *Note `mysql_stmt_result_metadata()': mysql-stmt-result-metadata. contains only metadata. It does not contain any row results. The rows are obtained by using the statement handle with *Note `mysql_stmt_fetch()': mysql-stmt-fetch. * Return Values * A `MYSQL_RES' result structure. `NULL' if no meta information exists for the prepared query. * Errors * * `CR_OUT_OF_MEMORY' Out of memory. * `CR_UNKNOWN_ERROR' An unknown error occurred. * Example * See the Example in *Note mysql-stmt-fetch::.  File: manual.info, Node: mysql-stmt-row-seek, Next: mysql-stmt-row-tell, Prev: mysql-stmt-result-metadata, Up: c-api-prepared-statement-functions 21.9.7.23 `mysql_stmt_row_seek()' ................................. `MYSQL_ROW_OFFSET mysql_stmt_row_seek(MYSQL_STMT *stmt, MYSQL_ROW_OFFSET offset)' * Description * Sets the row cursor to an arbitrary row in a statement result set. The `offset' value is a row offset that should be a value returned from *Note `mysql_stmt_row_tell()': mysql-stmt-row-tell. or from *Note `mysql_stmt_row_seek()': mysql-stmt-row-seek. This value is not a row number; if you want to seek to a row within a result set by number, use *Note `mysql_stmt_data_seek()': mysql-stmt-data-seek. instead. This function requires that the result set structure contains the entire result of the query, so *Note `mysql_stmt_row_seek()': mysql-stmt-row-seek. may be used only in conjunction with *Note `mysql_stmt_store_result()': mysql-stmt-store-result. * Return Values * The previous value of the row cursor. This value may be passed to a subsequent call to *Note `mysql_stmt_row_seek()': mysql-stmt-row-seek. * Errors * None.  File: manual.info, Node: mysql-stmt-row-tell, Next: mysql-stmt-send-long-data, Prev: mysql-stmt-row-seek, Up: c-api-prepared-statement-functions 21.9.7.24 `mysql_stmt_row_tell()' ................................. `MYSQL_ROW_OFFSET mysql_stmt_row_tell(MYSQL_STMT *stmt)' * Description * Returns the current position of the row cursor for the last *Note `mysql_stmt_fetch()': mysql-stmt-fetch. This value can be used as an argument to *Note `mysql_stmt_row_seek()': mysql-stmt-row-seek. You should use *Note `mysql_stmt_row_tell()': mysql-stmt-row-tell. only after *Note `mysql_stmt_store_result()': mysql-stmt-store-result. * Return Values * The current offset of the row cursor. * Errors * None.  File: manual.info, Node: mysql-stmt-send-long-data, Next: mysql-stmt-sqlstate, Prev: mysql-stmt-row-tell, Up: c-api-prepared-statement-functions 21.9.7.25 `mysql_stmt_send_long_data()' ....................................... `my_bool mysql_stmt_send_long_data(MYSQL_STMT *stmt, unsigned int parameter_number, const char *data, unsigned long length)' * Description * Enables an application to send parameter data to the server in pieces (or `chunks'). Call this function after *Note `mysql_stmt_bind_param()': mysql-stmt-bind-param. and before *Note `mysql_stmt_execute()': mysql-stmt-execute. It can be called multiple times to send the parts of a character or binary data value for a column, which must be one of the *Note `TEXT': blob. or *Note `BLOB': blob. data types. `parameter_number' indicates which parameter to associate the data with. Parameters are numbered beginning with 0. `data' is a pointer to a buffer containing data to be sent, and `length' indicates the number of bytes in the buffer. *Note*: The next *Note `mysql_stmt_execute()': mysql-stmt-execute. call ignores the bind buffer for all parameters that have been used with *Note `mysql_stmt_send_long_data()': mysql-stmt-send-long-data. since last *Note `mysql_stmt_execute()': mysql-stmt-execute. or *Note `mysql_stmt_reset()': mysql-stmt-reset. If you want to reset/forget the sent data, you can do it with *Note `mysql_stmt_reset()': mysql-stmt-reset. See *Note mysql-stmt-reset::. As of MySQL 5.1.57, the `max_long_data_size' system variable controls the maximum size of parameter values that can be sent with `mysql_stmt_send_long_data()'. If this variable not set at server startup, the default is the value of the `max_allowed_packet' system variable. `max_long_data_size' is deprecated. In MySQL 5.6, it is removed and the maximum parameter size is controlled by `max_allowed_packet'. * Return Values * Zero if the data is sent successfully to server. Nonzero if an error occurred. * Errors * * `CR_INVALID_BUFFER_USE' The parameter does not have a string or binary type. * `CR_COMMANDS_OUT_OF_SYNC' Commands were executed in an improper order. * `CR_SERVER_GONE_ERROR' The MySQL server has gone away. * `CR_OUT_OF_MEMORY' Out of memory. * `CR_UNKNOWN_ERROR' An unknown error occurred. * Example * The following example demonstrates how to send the data for a *Note `TEXT': blob. column in chunks. It inserts the data value `'MySQL - The most popular Open Source database'' into the `text_column' column. The `mysql' variable is assumed to be a valid connection handle. #define INSERT_QUERY "INSERT INTO \ test_long_data(text_column) VALUES(?)" MYSQL_BIND bind[1]; long length; stmt = mysql_stmt_init(mysql); if (!stmt) { fprintf(stderr, " mysql_stmt_init(), out of memory\n"); exit(0); } if (mysql_stmt_prepare(stmt, INSERT_QUERY, strlen(INSERT_QUERY))) { fprintf(stderr, "\n mysql_stmt_prepare(), INSERT failed"); fprintf(stderr, "\n %s", mysql_stmt_error(stmt)); exit(0); } memset(bind, 0, sizeof(bind)); bind[0].buffer_type= MYSQL_TYPE_STRING; bind[0].length= &length; bind[0].is_null= 0; /* Bind the buffers */ if (mysql_stmt_bind_param(stmt, bind)) { fprintf(stderr, "\n param bind failed"); fprintf(stderr, "\n %s", mysql_stmt_error(stmt)); exit(0); } /* Supply data in chunks to server */ if (mysql_stmt_send_long_data(stmt,0,"MySQL",5)) { fprintf(stderr, "\n send_long_data failed"); fprintf(stderr, "\n %s", mysql_stmt_error(stmt)); exit(0); } /* Supply the next piece of data */ if (mysql_stmt_send_long_data(stmt,0, " - The most popular Open Source database",40)) { fprintf(stderr, "\n send_long_data failed"); fprintf(stderr, "\n %s", mysql_stmt_error(stmt)); exit(0); } /* Now, execute the query */ if (mysql_stmt_execute(stmt)) { fprintf(stderr, "\n mysql_stmt_execute failed"); fprintf(stderr, "\n %s", mysql_stmt_error(stmt)); exit(0); }  File: manual.info, Node: mysql-stmt-sqlstate, Next: mysql-stmt-store-result, Prev: mysql-stmt-send-long-data, Up: c-api-prepared-statement-functions 21.9.7.26 `mysql_stmt_sqlstate()' ................................. `const char *mysql_stmt_sqlstate(MYSQL_STMT *stmt)' * Description * For the statement specified by `stmt', *Note `mysql_stmt_sqlstate()': mysql-stmt-sqlstate. returns a null-terminated string containing the SQLSTATE error code for the most recently invoked prepared statement API function that can succeed or fail. The error code consists of five characters. `"00000"' means `no error.' The values are specified by ANSI SQL and ODBC. For a list of possible values, see *Note error-handling::. Note that not all MySQL errors are yet mapped to SQLSTATE codes. The value `"HY000"' (general error) is used for unmapped errors. * Return Values * A null-terminated character string containing the SQLSTATE error code.  File: manual.info, Node: mysql-stmt-store-result, Prev: mysql-stmt-sqlstate, Up: c-api-prepared-statement-functions 21.9.7.27 `mysql_stmt_store_result()' ..................................... `int mysql_stmt_store_result(MYSQL_STMT *stmt)' * Description * Result sets are produced by calling *Note `mysql_stmt_execute()': mysql-stmt-execute. to executed prepared statements for SQL statements such as *Note `SELECT': select, *Note `SHOW': show, *Note `DESCRIBE': describe, and *Note `EXPLAIN': explain. By default, result sets for successfully executed prepared statements are not buffered on the client and *Note `mysql_stmt_fetch()': mysql-stmt-fetch. fetches them one at a time from the server. To cause the complete result set to be buffered on the client, call *Note `mysql_stmt_store_result()': mysql-stmt-store-result. after binding data buffers with *Note `mysql_stmt_bind_result()': mysql-stmt-bind-result. and before calling *Note `mysql_stmt_fetch()': mysql-stmt-fetch. to fetch rows. (For an example, see *Note mysql-stmt-fetch::.) *Note `mysql_stmt_store_result()': mysql-stmt-store-result. is optional for result set processing, unless you will call *Note `mysql_stmt_data_seek()': mysql-stmt-data-seek, *Note `mysql_stmt_row_seek()': mysql-stmt-row-seek, or *Note `mysql_stmt_row_tell()': mysql-stmt-row-tell. Those functions require a seekable result set. It is unnecessary to call *Note `mysql_stmt_store_result()': mysql-stmt-store-result. after executing an SQL statement that does not produce a result set, but if you do, it does not harm or cause any notable performance problem. You can detect whether the statement produced a result set by checking if *Note `mysql_stmt_result_metadata()': mysql-stmt-result-metadata. returns `NULL'. For more information, refer to *Note mysql-stmt-result-metadata::. *Note*: MySQL doesn't by default calculate `MYSQL_FIELD->max_length' for all columns in *Note `mysql_stmt_store_result()': mysql-stmt-store-result. because calculating this would slow down *Note `mysql_stmt_store_result()': mysql-stmt-store-result. considerably and most applications don't need `max_length'. If you want `max_length' to be updated, you can call *Note `mysql_stmt_attr_set(MYSQL_STMT, STMT_ATTR_UPDATE_MAX_LENGTH, &flag)': mysql-stmt-attr-set. to enable this. See *Note mysql-stmt-attr-set::. * Return Values * Zero if the results are buffered successfully. Nonzero if an error occurred. * Errors * * `CR_COMMANDS_OUT_OF_SYNC' Commands were executed in an improper order. * `CR_OUT_OF_MEMORY' Out of memory. * `CR_SERVER_GONE_ERROR' The MySQL server has gone away. * `CR_SERVER_LOST' The connection to the server was lost during the query. * `CR_UNKNOWN_ERROR' An unknown error occurred.  File: manual.info, Node: c-api-thread-functions, Next: c-api-embedded-server-functions, Prev: c-api-prepared-statement-functions, Up: c 21.9.8 C API Threaded Function Descriptions ------------------------------------------- * Menu: * my-init:: `my_init()' * mysql-thread-end:: `mysql_thread_end()' * mysql-thread-init:: `mysql_thread_init()' * mysql-thread-safe:: `mysql_thread_safe()' To create a threaded client, use the functions described in the following sections. See also *Note threaded-clients::.  File: manual.info, Node: my-init, Next: mysql-thread-end, Prev: c-api-thread-functions, Up: c-api-thread-functions 21.9.8.1 `my_init()' .................... `void my_init(void)' * Description * *Note `my_init()': my-init. initializes some global variables that MySQL needs. If you are using a thread-safe client library, it also calls *Note `mysql_thread_init()': mysql-thread-init. for this thread. It is necessary for *Note `my_init()': my-init. to be called early in the initialization phase of a program's use of the MySQL library. However, *Note `my_init()': my-init. is automatically called by *Note `mysql_init()': mysql-init, *Note `mysql_library_init()': mysql-library-init, *Note `mysql_server_init()': mysql-server-init, and *Note `mysql_connect()': mysql-connect. If you ensure that your program invokes one of those functions before any other MySQL calls, there is no need to invoke *Note `my_init()': my-init. explicitly. To access the prototype for *Note `my_init()': my-init, your program should include these header files: #include #include * Return Values * None.  File: manual.info, Node: mysql-thread-end, Next: mysql-thread-init, Prev: my-init, Up: c-api-thread-functions 21.9.8.2 `mysql_thread_end()' ............................. `void mysql_thread_end(void)' * Description * This function needs to be called before calling `pthread_exit()' to free memory allocated by *Note `mysql_thread_init()': mysql-thread-init. *Note `mysql_thread_end()': mysql-thread-end. _is not invoked automatically by the client library_. It must be called explicitly to avoid a memory leak. * Return Values * None.  File: manual.info, Node: mysql-thread-init, Next: mysql-thread-safe, Prev: mysql-thread-end, Up: c-api-thread-functions 21.9.8.3 `mysql_thread_init()' .............................. `my_bool mysql_thread_init(void)' * Description * This function must be called early within each created thread to initialize thread-specific variables. However, you may not necessarily need to invoke it explicitly: *Note `mysql_thread_init()': mysql-thread-init. is automatically called by *Note `my_init()': my-init, which itself is automatically called by *Note `mysql_init()': mysql-init, *Note `mysql_library_init()': mysql-library-init, *Note `mysql_server_init()': mysql-server-init, and *Note `mysql_connect()': mysql-connect. If you invoke any of those functions, *Note `mysql_thread_init()': mysql-thread-init. will be called for you. * Return Values * Zero if successful. Nonzero if an error occurred.  File: manual.info, Node: mysql-thread-safe, Prev: mysql-thread-init, Up: c-api-thread-functions 21.9.8.4 `mysql_thread_safe()' .............................. `unsigned int mysql_thread_safe(void)' * Description * This function indicates whether the client library is compiled as thread-safe. * Return Values * 1 if the client library is thread-safe, 0 otherwise.  File: manual.info, Node: c-api-embedded-server-functions, Next: c-api-problems, Prev: c-api-thread-functions, Up: c 21.9.9 C API Embedded Server Function Descriptions -------------------------------------------------- * Menu: * mysql-server-init:: `mysql_server_init()' * mysql-server-end:: `mysql_server_end()' MySQL applications can be written to use an embedded server. See *Note libmysqld::. To write such an application, you must link it against the `libmysqld' library by using the `-lmysqld' flag rather than linking it against the `libmysqlclient' client library by using the `-lmysqlclient' flag. However, the calls to initialize and finalize the library are the same whether you write a client application or one that uses the embedded server: Call *Note `mysql_library_init()': mysql-library-init. to initialize the library and *Note `mysql_library_end()': mysql-library-end. when you are done with it. See *Note c-api-function-overview::.  File: manual.info, Node: mysql-server-init, Next: mysql-server-end, Prev: c-api-embedded-server-functions, Up: c-api-embedded-server-functions 21.9.9.1 `mysql_server_init()' .............................. `int mysql_server_init(int argc, char **argv, char **groups)' * Description * This function initializes the MySQL library, which must be done before you call any other MySQL function. However, *Note `mysql_server_init()': mysql-server-init. is deprecated and you should call *Note `mysql_library_init()': mysql-library-init. instead. See *Note mysql-library-init::. * Return Values * Zero if successful. Nonzero if an error occurred.  File: manual.info, Node: mysql-server-end, Prev: mysql-server-init, Up: c-api-embedded-server-functions 21.9.9.2 `mysql_server_end()' ............................. `void mysql_server_end(void)' * Description * This function finalizes the MySQL library, which should be done when you are done using the library. However, *Note `mysql_server_end()': mysql-server-end. is deprecated and *Note `mysql_library_end()': mysql-library-end. should be used instead. See *Note mysql-library-end::. * Return Values * None.  File: manual.info, Node: c-api-problems, Next: auto-reconnect, Prev: c-api-embedded-server-functions, Up: c 21.9.10 Common Questions and Problems When Using the C API ---------------------------------------------------------- * Menu: * null-mysql-store-result:: Why `mysql_store_result()' Sometimes Returns `NULL' After `mysql_query()' Returns Success * query-results:: What Results You Can Get from a Query * getting-unique-id:: How to Get the Unique ID for the Last Inserted Row  File: manual.info, Node: null-mysql-store-result, Next: query-results, Prev: c-api-problems, Up: c-api-problems 21.9.10.1 Why `mysql_store_result()' Sometimes Returns `NULL' After `mysql_query()' Returns Success ................................................................................................... It is possible for *Note `mysql_store_result()': mysql-store-result. to return `NULL' following a successful call to *Note `mysql_query()': mysql-query. When this happens, it means one of the following conditions occurred: * There was a `malloc()' failure (for example, if the result set was too large). * The data couldn't be read (an error occurred on the connection). * The query returned no data (for example, it was an *Note `INSERT': insert, *Note `UPDATE': update, or *Note `DELETE': delete.). You can always check whether the statement should have produced a nonempty result by calling *Note `mysql_field_count()': mysql-field-count. If *Note `mysql_field_count()': mysql-field-count. returns zero, the result is empty and the last query was a statement that does not return values (for example, an *Note `INSERT': insert. or a *Note `DELETE': delete.). If *Note `mysql_field_count()': mysql-field-count. returns a nonzero value, the statement should have produced a nonempty result. See the description of the *Note `mysql_field_count()': mysql-field-count. function for an example. You can test for an error by calling *Note `mysql_error()': mysql-error. or *Note `mysql_errno()': mysql-errno.  File: manual.info, Node: query-results, Next: getting-unique-id, Prev: null-mysql-store-result, Up: c-api-problems 21.9.10.2 What Results You Can Get from a Query ............................................... In addition to the result set returned by a query, you can also get the following information: * *Note `mysql_affected_rows()': mysql-affected-rows. returns the number of rows affected by the last query when doing an *Note `INSERT': insert, *Note `UPDATE': update, or *Note `DELETE': delete. For a fast re-create, use *Note `TRUNCATE TABLE': truncate-table. * *Note `mysql_num_rows()': mysql-num-rows. returns the number of rows in a result set. With *Note `mysql_store_result()': mysql-store-result, *Note `mysql_num_rows()': mysql-num-rows. may be called as soon as *Note `mysql_store_result()': mysql-store-result. returns. With *Note `mysql_use_result()': mysql-use-result, *Note `mysql_num_rows()': mysql-num-rows. may be called only after you have fetched all the rows with *Note `mysql_fetch_row()': mysql-fetch-row. * *Note `mysql_insert_id()': mysql-insert-id. returns the ID generated by the last query that inserted a row into a table with an `AUTO_INCREMENT' index. See *Note mysql-insert-id::. * Some queries (*Note `LOAD DATA INFILE ...': load-data, *Note `INSERT INTO ... SELECT ...': insert-select, *Note `UPDATE': update.) return additional information. The result is returned by *Note `mysql_info()': mysql-info. See the description for *Note `mysql_info()': mysql-info. for the format of the string that it returns. *Note `mysql_info()': mysql-info. returns a `NULL' pointer if there is no additional information.  File: manual.info, Node: getting-unique-id, Prev: query-results, Up: c-api-problems 21.9.10.3 How to Get the Unique ID for the Last Inserted Row ............................................................ If you insert a record into a table that contains an `AUTO_INCREMENT' column, you can obtain the value stored into that column by calling the *Note `mysql_insert_id()': mysql-insert-id. function. You can check from your C applications whether a value was stored in an `AUTO_INCREMENT' column by executing the following code (which assumes that you've checked that the statement succeeded). It determines whether the query was an *Note `INSERT': insert. with an `AUTO_INCREMENT' index: if ((result = mysql_store_result(&mysql)) == 0 && mysql_field_count(&mysql) == 0 && mysql_insert_id(&mysql) != 0) { used_id = mysql_insert_id(&mysql); } When a new `AUTO_INCREMENT' value has been generated, you can also obtain it by executing a `SELECT LAST_INSERT_ID()' statement with *Note `mysql_query()': mysql-query. and retrieving the value from the result set returned by the statement. When inserting multiple values, the last automatically incremented value is returned. For `LAST_INSERT_ID()', the most recently generated ID is maintained in the server on a per-connection basis. It is not changed by another client. It is not even changed if you update another `AUTO_INCREMENT' column with a nonmagic value (that is, a value that is not `NULL' and not `0'). Using `LAST_INSERT_ID()' and `AUTO_INCREMENT' columns simultaneously from multiple clients is perfectly valid. Each client will receive the last inserted ID for the last statement _that_ client executed. If you want to use the ID that was generated for one table and insert it into a second table, you can use SQL statements like this: INSERT INTO foo (auto,text) VALUES(NULL,'text'); # generate ID by inserting NULL INSERT INTO foo2 (id,text) VALUES(LAST_INSERT_ID(),'text'); # use ID in second table Note that *Note `mysql_insert_id()': mysql-insert-id. returns the value stored into an `AUTO_INCREMENT' column, whether that value is automatically generated by storing `NULL' or `0' or was specified as an explicit value. `LAST_INSERT_ID()' returns only automatically generated `AUTO_INCREMENT' values. If you store an explicit value other than `NULL' or `0', it does not affect the value returned by `LAST_INSERT_ID()'. For more information on obtaining the last ID in an `AUTO_INCREMENT' column: * For information on `LAST_INSERT_ID()', which can be used within an SQL statement, see *Note information-functions::. * For information on *Note `mysql_insert_id()': mysql-insert-id, the function you use from within the C API, see *Note mysql-insert-id::. * For information on obtaining the auto-incremented value when using Connector/J, see *Note connector-j-usagenotes::. * For information on obtaining the auto-incremented value when using Connector/ODBC, see *Note connector-odbc-usagenotes-functionality-last-insert-id::.  File: manual.info, Node: auto-reconnect, Next: c-api-multiple-queries, Prev: c-api-problems, Up: c 21.9.11 Controlling Automatic Reconnection Behavior --------------------------------------------------- The MySQL client library can perform an automatic reconnection to the server if it finds that the connection is down when you attempt to send a statement to the server to be executed. In this case, the library tries once to reconnect to the server and send the statement again. In MySQL 5.1, auto-reconnect is disabled by default. If it is important for your application to know that the connection has been dropped (so that is can exit or take action to adjust for the loss of state information), be sure that auto-reconnect is disabled. To ensure this, call *Note `mysql_options()': mysql-options. with the `MYSQL_OPT_RECONNECT' option: my_bool reconnect = 0; mysql_options(&mysql, MYSQL_OPT_RECONNECT, &reconnect); If the connection has gone down, the effect of *Note `mysql_ping()': mysql-ping. depends on the auto-reconnect state. If auto-reconnect is enabled, *Note `mysql_ping()': mysql-ping. performs a reconnect. Otherwise, it returns an error. Some client programs might provide the capability of controlling automatic reconnection. For example, *Note `mysql': mysql. reconnects by default, but the `--skip-reconnect' option can be used to suppress this behavior. If an automatic reconnection does occur (for example, as a result of calling *Note `mysql_ping()': mysql-ping.), there is no explicit indication of it. To check for reconnection, call *Note `mysql_thread_id()': mysql-thread-id. to get the original connection identifier before calling *Note `mysql_ping()': mysql-ping, then call *Note `mysql_thread_id()': mysql-thread-id. again to see whether the identifier has changed. Automatic reconnection can be convenient because you need not implement your own reconnect code, but if a reconnection does occur, several aspects of the connection state are reset on the server side and your application will not know about it. The connection-related state is affected as follows: * Any active transactions are rolled back and autocommit mode is reset. * All table locks are released. * All `TEMPORARY' tables are closed (and dropped). * Session variables are reinitialized to the values of the corresponding variables. This also affects variables that are set implicitly by statements such as `SET NAMES'. * User variable settings are lost. * Prepared statements are released. * *Note `HANDLER': handler. variables are closed. * The value of `LAST_INSERT_ID()' is reset to 0. * Locks acquired with `GET_LOCK()' are released. If the connection drops, it is possible that the session associated with the connection on the server side will still be running if the server has not yet detected that the client is no longer connected. In this case, any locks held by the original connection still belong to that session, so you may want to kill it by calling *Note `mysql_kill()': mysql-kill.  File: manual.info, Node: c-api-multiple-queries, Next: c-api-prepared-statement-problems, Prev: auto-reconnect, Up: c 21.9.12 C API Support for Multiple Statement Execution ------------------------------------------------------ By default, *Note `mysql_query()': mysql-query. and *Note `mysql_real_query()': mysql-real-query. interpret their statement string argument as a single statement to be executed, and you process the result according to whether the statement produces a result set (a set of rows, as for *Note `SELECT': select.) or an affected-rows count (as for *Note `INSERT': insert, *Note `UPDATE': update, and so forth). MySQL 5.1 also supports the execution of a string containing multiple statements separated by semicolon (``;'') characters. This capability is enabled by special options that are specified either when you connect to the server with *Note `mysql_real_connect()': mysql-real-connect. or after connecting by calling` *Note `mysql_set_server_option()': mysql-set-server-option. Executing a multiple-statement string can produce multiple result sets or row-count indicators. Processing these results involves a different approach than for the single-statement case: After handling the result from the first statement, it is necessary to check whether more results exist and process them in turn if so. To support multiple-result processing, the C API includes the *Note `mysql_more_results()': mysql-more-results. and *Note `mysql_next_result()': mysql-next-result. functions. These functions are used at the end of a loop that iterates as long as more results are available. _Failure to process the result this way may result in a dropped connection to the server._ Multiple-result processing also is required if you execute *Note `CALL': call. statements for stored procedures. Results from a stored procedure have these characteristics: * Statements within the procedure may produce result sets (for example, if it executes *Note `SELECT': select. statements). These result sets are returned in the order that they are produced as the procedure executes. In general, the caller cannot know how many result sets a procedure will return. Procedure execution may depend on loops or conditional statements that cause the execution path to differ from one call to the next. Therefore, you must be prepared to retrieve multiple results. * The final result from the procedure is a status result that includes no result set. The status indicates whether the procedure succeeded or an error occurred. The multiple statement and result capabilities can be used only with *Note `mysql_query()': mysql-query. or *Note `mysql_real_query()': mysql-real-query. They cannot be used with the prepared statement interface. Prepared statement handles are defined to work only with strings that contain a single statement. See *Note c-api-prepared-statements::. To enable multiple-statement execution and result processing, the following options may be used: * The *Note `mysql_real_connect()': mysql-real-connect. function has a `flags' argument for which two option values are relevant: * `CLIENT_MULTI_RESULTS' enables the client program to process multiple results. This option _must_ be enabled if you execute *Note `CALL': call. statements for stored procedures that produce result sets. Otherwise, such procedures result in an error `Error 1312 (0A000): PROCEDURE PROC_NAME can't return a result set in the given context'. * `CLIENT_MULTI_STATEMENTS' enables *Note `mysql_query()': mysql-query. and *Note `mysql_real_query()': mysql-real-query. to execute statement strings containing multiple statements separated by semicolons. This option also enables `CLIENT_MULTI_RESULTS' implicitly, so a `flags' argument of `CLIENT_MULTI_STATEMENTS' to *Note `mysql_real_connect()': mysql-real-connect. is equivalent to an argument of `CLIENT_MULTI_STATEMENTS | CLIENT_MULTI_RESULTS'. That is, `CLIENT_MULTI_STATEMENTS' is sufficient to enable multiple-statement execution and all multiple-result processing. * After the connection to the server has been established, you can use the *Note `mysql_set_server_option()': mysql-set-server-option. function to enable or disable multiple-statement execution by passing it an argument of `MYSQL_OPTION_MULTI_STATEMENTS_ON' or `MYSQL_OPTION_MULTI_STATEMENTS_OFF'. Enabling multiple-statement execution with this function also enables processing of `simple' results for a multiple-statement string where each statement produces a single result, but is _not_ sufficient to permit processing of stored procedures that produce result sets. The following procedure outlines a suggested strategy for handling multiple statements: 1. Pass `CLIENT_MULTI_STATEMENTS' to *Note `mysql_real_connect()': mysql-real-connect, to fully enable multiple-statement execution and multiple-result processing. 2. After calling *Note `mysql_query()': mysql-query. or *Note `mysql_real_query()': mysql-real-query. and verifying that it succeeds, enter a loop within which you process statement results. 3. For each iteration of the loop, handle the current statement result, retrieving either a result set or an affected-rows count. If an error occurs, exit the loop. 4. At the end of the loop, call *Note `mysql_next_result()': mysql-next-result. to check whether another result exists and initiate retrieval for it if so. If no more results are available, exit the loop. One possible implementation of the preceding strategy is shown following. The final part of the loop can be reduced to a simple test of whether *Note `mysql_next_result()': mysql-next-result. returns nonzero. The code as written distinguishes between no more results and an error, which enables a message to be printed for the latter occurrence. /* connect to server with the CLIENT_MULTI_STATEMENTS option */ if (mysql_real_connect (mysql, host_name, user_name, password, db_name, port_num, socket_name, CLIENT_MULTI_STATEMENTS) == NULL) { printf("mysql_real_connect() failed\n"); mysql_close(mysql); exit(1); } /* execute multiple statements */ status = mysql_query(mysql, "DROP TABLE IF EXISTS test_table;\ CREATE TABLE test_table(id INT);\ INSERT INTO test_table VALUES(10);\ UPDATE test_table SET id=20 WHERE id=10;\ SELECT * FROM test_table;\ DROP TABLE test_table"); if (status) { printf("Could not execute statement(s)"); mysql_close(mysql); exit(0); } /* process each statement result */ do { /* did current statement return data? */ result = mysql_store_result(mysql); if (result) { /* yes; process rows and free the result set */ process_result_set(mysql, result); mysql_free_result(result); } else /* no result set or error */ { if (mysql_field_count(mysql) == 0) { printf("%lld rows affected\n", mysql_affected_rows(mysql)); } else /* some error occurred */ { printf("Could not retrieve result set\n"); break; } } /* more results? -1 = no, >0 = error, 0 = yes (keep looping) */ if ((status = mysql_next_result(mysql)) > 0) printf("Could not execute statement\n"); } while (status == 0); mysql_close(mysql);  File: manual.info, Node: c-api-prepared-statement-problems, Next: c-api-prepared-statement-date-handling, Prev: c-api-multiple-queries, Up: c 21.9.13 C API Prepared Statement Problems ----------------------------------------- Here follows a list of the currently known problems with prepared statements: * *Note `TIME': time, *Note `TIMESTAMP': datetime, and *Note `DATETIME': datetime. do not support parts of seconds (for example, from `DATE_FORMAT()'). * When converting an integer to string, `ZEROFILL' is honored with prepared statements in some cases where the MySQL server doesn't print the leading zeros. (For example, with `MIN(NUMBER-WITH-ZEROFILL)'). * When converting a floating-point number to a string in the client, the rightmost digits of the converted value may differ slightly from those of the original value. * Before MySQL 5.1.17, prepared statements do not use the query cache. As of 5.1.17, prepared statements use the query cache under the conditions described in *Note query-cache-operation::. * Prepared statements do not support multi-statements (that is, multiple statements within a single string separated by ``;'' characters). * In MySQL 5.1, prepared *Note `CALL': call. statements cannot invoke stored procedures that return result sets because prepared statements do not support multiple result sets. Nor can the calling application access a stored procedure's `OUT' or `INOUT' parameters when the procedure returns. These capabilities are supported beginning with MySQL 5.5.  File: manual.info, Node: c-api-prepared-statement-date-handling, Next: c-api-prepared-call-statements, Prev: c-api-prepared-statement-problems, Up: c 21.9.14 C API Prepared Statement Handling of Date and Time Values ----------------------------------------------------------------- The binary (prepared statement) protocol enables you to send and receive date and time values (*Note `DATE': datetime, *Note `TIME': time, *Note `DATETIME': datetime, and *Note `TIMESTAMP': datetime.), using the `MYSQL_TIME' structure. The members of this structure are described in *Note c-api-prepared-statement-data-structures::. To send temporal data values, create a prepared statement using *Note `mysql_stmt_prepare()': mysql-stmt-prepare. Then, before calling *Note `mysql_stmt_execute()': mysql-stmt-execute. to execute the statement, use the following procedure to set up each temporal parameter: 1. In the `MYSQL_BIND' structure associated with the data value, set the `buffer_type' member to the type that indicates what kind of temporal value you're sending. For *Note `DATE': datetime, *Note `TIME': time, *Note `DATETIME': datetime, or *Note `TIMESTAMP': datetime. values, set `buffer_type' to `MYSQL_TYPE_DATE', `MYSQL_TYPE_TIME', `MYSQL_TYPE_DATETIME', or `MYSQL_TYPE_TIMESTAMP', respectively. 2. Set the `buffer' member of the `MYSQL_BIND' structure to the address of the `MYSQL_TIME' structure in which you pass the temporal value. 3. Fill in the members of the `MYSQL_TIME' structure that are appropriate for the type of temporal value to be passed. Use *Note `mysql_stmt_bind_param()': mysql-stmt-bind-param. to bind the parameter data to the statement. Then you can call *Note `mysql_stmt_execute()': mysql-stmt-execute. To retrieve temporal values, the procedure is similar, except that you set the `buffer_type' member to the type of value you expect to receive, and the `buffer' member to the address of a `MYSQL_TIME' structure into which the returned value should be placed. Use *Note `mysql_stmt_bind_result()': mysql-stmt-bind-result. to bind the buffers to the statement after calling *Note `mysql_stmt_execute()': mysql-stmt-execute. and before fetching the results. Here is a simple example that inserts *Note `DATE': datetime, *Note `TIME': time, and *Note `TIMESTAMP': datetime. data. The `mysql' variable is assumed to be a valid connection handle. MYSQL_TIME ts; MYSQL_BIND bind[3]; MYSQL_STMT *stmt; strmov(query, "INSERT INTO test_table(date_field, time_field, \ timestamp_field) VALUES(?,?,?"); stmt = mysql_stmt_init(mysql); if (!stmt) { fprintf(stderr, " mysql_stmt_init(), out of memory\n"); exit(0); } if (mysql_stmt_prepare(mysql, query, strlen(query))) { fprintf(stderr, "\n mysql_stmt_prepare(), INSERT failed"); fprintf(stderr, "\n %s", mysql_stmt_error(stmt)); exit(0); } /* set up input buffers for all 3 parameters */ bind[0].buffer_type= MYSQL_TYPE_DATE; bind[0].buffer= (char *)&ts; bind[0].is_null= 0; bind[0].length= 0; ... bind[1]= bind[2]= bind[0]; ... mysql_stmt_bind_param(stmt, bind); /* supply the data to be sent in the ts structure */ ts.year= 2002; ts.month= 02; ts.day= 03; ts.hour= 10; ts.minute= 45; ts.second= 20; mysql_stmt_execute(stmt); ..  File: manual.info, Node: c-api-prepared-call-statements, Next: building-clients, Prev: c-api-prepared-statement-date-handling, Up: c 21.9.15 C API Support for Prepared `CALL' Statements ---------------------------------------------------- In MySQL 5.1, prepared *Note `CALL': call. statements can be used only for stored procedures that produce at most one result set. Nor can the calling application use placeholders for `OUT' or `INOUT' parameters. MySQL 5.5 expands prepared *Note `CALL': call. statement support for stored procedures that produce multiple result sets and to provide placeholder access to `OUT' and `INOUT' parameters.  File: manual.info, Node: building-clients, Prev: c-api-prepared-call-statements, Up: c 21.9.16 Building Client Programs -------------------------------- * Menu: * c-api-linking-problems:: Problems Linking to the MySQL Client Library * threaded-clients:: How to Write a Threaded Client If you compile MySQL clients that you've written yourself or that you obtain from a third-party, they must be linked using the `-lmysqlclient -lz' options in the link command. You may also need to specify a `-L' option to tell the linker where to find the library. For example, if the library is installed in `/usr/local/mysql/lib', use `-L/usr/local/mysql/lib -lmysqlclient -lz' in the link command. For clients that use MySQL header files, you may need to specify an `-I' option when you compile them (for example, `-I/usr/local/mysql/include'), so that the compiler can find the header files. * Compiling MySQL Clients on Unix * To make it simpler to compile MySQL programs on Unix, we have provided the *Note `mysql_config': mysql-config. script for you. See *Note mysql-config::. You can use it to compile a MySQL client as follows: CFG=/usr/local/mysql/bin/mysql_config sh -c "gcc -o progname `$CFG --cflags` progname.c `$CFG --libs`" The `sh -c' is needed to get the shell not to treat the output from *Note `mysql_config': mysql-config. as one word. * Compiling MySQL Clients on Microsoft Windows * On Windows, you can link your code with either the dynamic or static client library. The static library is named `mysqlclient' and the dynamic library is named `libmysql'. If you link with the static library, failure can occur if certain conditions are not satisfied: * The client application must be compiled with exactly the same version of Visual Studio as that used to compile the library. * The client application should link the C runtime statically by using the `/MT' compiler option. If the client application is built in in debug mode and uses the static debug C runtime (`/MTd' compiler option), it can link the `mysqlclient' if that library was built using the same option. If the client application uses the dynamic C runtime (`/MD' option, or `/MDd' option in debug mode), it cannot link with the static client library and must use the dynamic library. The MSDN page describing the link options can be found here: `http://msdn.microsoft.com/en-us/library/2kzt1wy3.aspx'  File: manual.info, Node: c-api-linking-problems, Next: threaded-clients, Prev: building-clients, Up: building-clients 21.9.16.1 Problems Linking to the MySQL Client Library ...................................................... When linking with the C API, the following errors may occur on some systems: gcc -g -o client test.o -L/usr/local/lib/mysql \ -lmysqlclient -lsocket -lnsl Undefined first referenced symbol in file floor /usr/local/lib/mysql/libmysqlclient.a(password.o) ld: fatal: Symbol referencing errors. No output written to client If this happens on your system, you must include the math library by adding `-lm' to the end of the compile/link line. Linking with the single-threaded library (`libmysqlclient') may lead to linker errors related to `pthread' symbols. When using the single-threaded library, please compile your client with `MYSQL_CLIENT_NO_THREADS' defined. This can be done on the command line by using the `-D' option to the compiler, or in your source code before including the MySQL header files. This define should not be used when building for use with the thread-safe client library (`libmysqlclient_r'). When you are linking an application program to use the MySQL client library, you might get undefined reference errors for symbols that start with `mysql_', such as those shown here: /tmp/ccFKsdPa.o: In function `main': /tmp/ccFKsdPa.o(.text+0xb): undefined reference to `mysql_init' /tmp/ccFKsdPa.o(.text+0x31): undefined reference to `mysql_real_connect' /tmp/ccFKsdPa.o(.text+0x57): undefined reference to `mysql_real_connect' /tmp/ccFKsdPa.o(.text+0x69): undefined reference to `mysql_error' /tmp/ccFKsdPa.o(.text+0x9a): undefined reference to `mysql_close' You should be able to solve this problem by adding `-Ldir_path -lmysqlclient' at the end of your link command, where `dir_path' represents the path name of the directory where the client library is located. To determine the correct directory, try this command: shell> mysql_config --libs The output from *Note `mysql_config': mysql-config. might indicate other libraries that should be specified on the link command as well. If you get `undefined reference' errors for the `uncompress' or `compress' function, add `-lz' to the end of your link command and try again. If you get `undefined reference' errors for a function that should exist on your system, such as `connect', check the manual page for the function in question to determine which libraries you should add to the link command. You might get `undefined reference' errors such as the following for functions that don't exist on your system: mf_format.o(.text+0x201): undefined reference to `__lxstat' This usually means that your MySQL client library was compiled on a system that is not 100% compatible with yours. In this case, you should download the latest MySQL source distribution and compile MySQL yourself. See *Note source-installation::. You might get undefined reference errors at runtime when you try to execute a MySQL program. If these errors specify symbols that start with `mysql_' or indicate that the `mysqlclient' library can't be found, it means that your system can't find the shared `libmysqlclient.so' library. The fix for this is to tell your system to search for shared libraries where the library is located. Use whichever of the following methods is appropriate for your system: * Add the path to the directory where `libmysqlclient.so' is located to the `LD_LIBRARY_PATH' environment variable. * Add the path to the directory where `libmysqlclient.so' is located to the `LD_LIBRARY' environment variable. * Copy `libmysqlclient.so' to some directory that is searched by your system, such as `/lib', and update the shared library information by executing `ldconfig'. Another way to solve this problem is by linking your program statically with the `-static' option, or by removing the dynamic MySQL libraries before linking your code. Before trying the second method, you should be sure that no other programs are using the dynamic libraries.  File: manual.info, Node: threaded-clients, Prev: c-api-linking-problems, Up: building-clients 21.9.16.2 How to Write a Threaded Client ........................................ The client library is almost thread-safe. The biggest problem is that the subroutines in `net.c' that read from sockets are not interrupt safe. This was done with the thought that you might want to have your own alarm that can break a long read to a server. If you install interrupt handlers for the `SIGPIPE' interrupt, the socket handling should be thread-safe. To avoid aborting the program when a connection terminates, MySQL blocks `SIGPIPE' on the first call to *Note `mysql_library_init()': mysql-library-init, *Note `mysql_init()': mysql-init, or *Note `mysql_connect()': mysql-connect. If you want to use your own `SIGPIPE' handler, you should first call *Note `mysql_library_init()': mysql-library-init. and then install your handler. Current binary distributions should have both a normal client library, `libmysqlclient', and a thread-safe library, `libmysqlclient_r'. For threaded clients, link against the latter library. If `undefined symbol' errors occur, in most cases this is because you have not included the thread libraries on the link/compile command. The thread-safe client library, `libmysqlclient_r', is thread-safe per connection. You can let two threads share the same connection with the following caveats: * Two threads can't send a query to the MySQL server at the same time on the same connection. In particular, you have to ensure that between calls to *Note `mysql_query()': mysql-query. and *Note `mysql_store_result()': mysql-store-result. no other thread is using the same connection. * Many threads can access different result sets that are retrieved with *Note `mysql_store_result()': mysql-store-result. * If you use *Note `mysql_use_result()': mysql-use-result, you must ensure that no other thread is using the same connection until the result set is closed. However, it really is best for threaded clients that share the same connection to use *Note `mysql_store_result()': mysql-store-result. * If you want to use multiple threads on the same connection, you must have a mutex lock around your pair of *Note `mysql_query()': mysql-query. and *Note `mysql_store_result()': mysql-store-result. calls. Once *Note `mysql_store_result()': mysql-store-result. is ready, the lock can be released and other threads may query the same connection. * If you use POSIX threads, you can use `pthread_mutex_lock()' and `pthread_mutex_unlock()' to establish and release a mutex lock. You need to know the following if you have a thread that did not create the connection to the MySQL database but is calling MySQL functions: When you call *Note `mysql_init()': mysql-init, MySQL creates a thread-specific variable for the thread that is used by the debug library (among other things). If you call a MySQL function before the thread has called *Note `mysql_init()': mysql-init, the thread does not have the necessary thread-specific variables in place and you are likely to end up with a core dump sooner or later. To avoid problems, you must do the following: 1. Call *Note `mysql_library_init()': mysql-library-init. before any other MySQL functions. It is not thread-safe, so call it before threads are created, or protect the call with a mutex. 2. Arrange for *Note `mysql_thread_init()': mysql-thread-init. to be called early in the thread handler before calling any MySQL function. If you call *Note `mysql_init()': mysql-init, it will call *Note `mysql_thread_init()': mysql-thread-init. for you. 3. In the thread, call *Note `mysql_thread_end()': mysql-thread-end. before calling `pthread_exit()'. This frees the memory used by MySQL thread-specific variables. The preceding notes regarding *Note `mysql_init()': mysql-init. also apply to *Note `mysql_connect()': mysql-connect, which calls *Note `mysql_init()': mysql-init.  File: manual.info, Node: apis-php, Next: apis-perl, Prev: c, Up: connectors-apis 21.10 MySQL PHP API =================== * Menu: * connector-php:: Connector/PHP * apis-php-problems:: Common Problems with MySQL and PHP * php-mysql-mysqli:: Enabling Both `mysql' and `mysqli' in PHP PHP is a server-side, HTML-embedded scripting language that may be used to create dynamic Web pages. It is available for most operating systems and Web servers, and can access most common databases, including MySQL. PHP may be run as a separate program or compiled as a module for use with the Apache Web server. PHP actually provides two different MySQL API extensions: * `mysql': Available for PHP versions 4 and 5, this extension is intended for use with MySQL versions prior to MySQL 4.1. This extension does not support the improved authentication protocol used in MySQL 4.1, nor does it support prepared statements or multiple statements. If you wish to use this extension with MySQL 4.1, you will likely want to configure the MySQL server to use the `--old-passwords' option (see *Note old-client::). This extension is documented on the PHP Web site at `http://php.net/mysql'. * See section "apis-php-mysqli" in the online manual - Stands for `MySQL, Improved'; this extension is available only in PHP 5. It is intended for use with MySQL 4.1.1 and later. This extension fully supports the authentication protocol used in MySQL 5.0, as well as the Prepared Statements and Multiple Statements APIs. In addition, this extension provides an advanced, object-oriented programming interface. You can read the documentation for the `mysqli' extension at `http://php.net/mysqli'. Helpful article can be found at `http://devzone.zend.com/node/view/id/686' and `http://devzone.zend.com/node/view/id/687'. If you're experiencing problems with enabling both the `mysql' and the `mysqli' extension when building PHP on Linux yourself, see *Note php-mysql-mysqli::. The PHP distribution and documentation are available from the PHP Web site (http://www.php.net/). _Portions of this section are Copyright (c) 1997-2008 the PHP Documentation Group_ This material may be distributed only subject to the terms and conditions set forth in the Creative Commons Attribution 3.0 License or later. A copy of the Creative Commons Attribution 3.0 license is distributed with this manual. The latest version is presently available at This material may be distributed only subject to the terms and conditio\ ns set forth in the Open Publication License, v1.0.8 or later (the latest version is presently available at http://www.opencontent.org/openpub/ (http://www.opencontent.org/openpub/)).  File: manual.info, Node: connector-php, Next: apis-php-problems, Prev: apis-php, Up: apis-php 21.10.1 Connector/PHP --------------------- The MySQL Connector/PHP is a version of the `mysql' and `mysqli' extensions for PHP optimized for the Windows operating system. Later versions of the main PHP `mysql'/`mysqli' drivers are compatible with Windows and a separate, Windows specific driver is no longer required. For PHP for all platforms, including Windows, you should use the `mysql' or `mysqli' extensions shipped with the PHP sources. See *Note apis-php::.  File: manual.info, Node: apis-php-problems, Next: php-mysql-mysqli, Prev: connector-php, Up: apis-php 21.10.2 Common Problems with MySQL and PHP ------------------------------------------ * `Error: Maximum Execution Time Exceeded': This is a PHP limit; go into the `php.ini' file and set the maximum execution time up from 30 seconds to something higher, as needed. It is also not a bad idea to double the RAM allowed per script to 16MB instead of 8MB. * `Fatal error: Call to unsupported or undefined function mysql_connect() in ...': This means that your PHP version isn't compiled with MySQL support. You can either compile a dynamic MySQL module and load it into PHP or recompile PHP with built-in MySQL support. This process is described in detail in the PHP manual. * `Error: Undefined reference to 'uncompress'': This means that the client library is compiled with support for a compressed client/server protocol. The fix is to add `-lz' last when linking with `-lmysqlclient'. * `Error: Client does not support authentication protocol': This is most often encountered when trying to use the older `mysql' extension with MySQL 4.1.1 and later. Possible solutions are: downgrade to MySQL 4.0; switch to PHP 5 and the newer `mysqli' extension; or configure the MySQL server with `--old-passwords'. (See *Note old-client::, for more information.) Those with PHP4 legacy code can make use of a compatibility layer for the old and new MySQL libraries, such as this one: `http://www.coggeshall.org/oss/mysql2i'.  File: manual.info, Node: php-mysql-mysqli, Prev: apis-php-problems, Up: apis-php 21.10.3 Enabling Both `mysql' and `mysqli' in PHP ------------------------------------------------- If you're experiencing problems with enabling both the `mysql' and the `mysqli' extension when building PHP on Linux yourself, you should try the following procedure. 1. Configure PHP like this: ./configure --with-mysqli=/usr/bin/mysql_config --with-mysql=/usr 2. Edit the `Makefile' and search for a line that starts with `EXTRA_LIBS'. It might look like this (all on one line): EXTRA_LIBS = -lcrypt -lcrypt -lmysqlclient -lz -lresolv -lm -ldl -lnsl -lxml2 -lz -lm -lxml2 -lz -lm -lmysqlclient -lz -lcrypt -lnsl -lm -lxml2 -lz -lm -lcrypt -lxml2 -lz -lm -lcrypt Remove all duplicates, so that the line looks like this (all on one line): EXTRA_LIBS = -lcrypt -lcrypt -lmysqlclient -lz -lresolv -lm -ldl -lnsl -lxml2 3. Build and install PHP: make make install  File: manual.info, Node: apis-perl, Next: apis-python, Prev: apis-php, Up: connectors-apis 21.11 MySQL Perl API ==================== The Perl `DBI' module provides a generic interface for database access. You can write a DBI script that works with many different database engines without change. To use DBI, you must install the `DBI' module, as well as a DataBase Driver (DBD) module for each type of server you want to access. For MySQL, this driver is the `DBD::mysql' module. Perl DBI is the recommended Perl interface. It replaces an older interface called `mysqlperl', which should be considered obsolete. Installation instructions for Perl DBI support are given in *Note perl-support::. DBI information is available at the command line, online, or in printed form: * Once you have the `DBI' and `DBD::mysql' modules installed, you can get information about them at the command line with the `perldoc' command: shell> perldoc DBI shell> perldoc DBI::FAQ shell> perldoc DBD::mysql You can also use `pod2man', `pod2html', and so forth to translate this information into other formats. * For online information about Perl DBI, visit the DBI Web site, `http://dbi.perl.org/'. That site hosts a general DBI mailing list. Oracle Corporation hosts a list specifically about `DBD::mysql'; see *Note mailing-lists::. * For printed information, the official DBI book is `Programming the Perl DBI' (Alligator Descartes and Tim Bunce, O'Reilly & Associates, 2000). Information about the book is available at the DBI Web site, `http://dbi.perl.org/'. For information that focuses specifically on using DBI with MySQL, see `MySQL and Perl for the Web' (Paul DuBois, New Riders, 2001). This book's Web site is `http://www.kitebird.com/mysql-perl/'.  File: manual.info, Node: apis-python, Next: apis-ruby, Prev: apis-perl, Up: connectors-apis 21.12 MySQL Python API ====================== `MySQLdb' provides MySQL support for Python, compliant with the Python DB API version 2.0. It can be found at `http://sourceforge.net/projects/mysql-python/'.  File: manual.info, Node: apis-ruby, Next: apis-tcl, Prev: apis-python, Up: connectors-apis 21.13 MySQL Ruby APIs ===================== * Menu: * apis-ruby-mysqlruby:: The MySQL/Ruby API * apis-ruby-rubymysql:: The Ruby/MySQL API Two APIs available for Ruby programmers. The MySQL/Ruby API is based on the `libmysql' API library. The Ruby/MySQL API is written to use the native MySQL network protocol (a native driver). For more information on Ruby, see Ruby Programming Language (http://www.ruby-lang.org). For information on installing and using the MySQL/Ruby API, see *Note apis-ruby-mysqlruby::. For information on installing and using the Ruby/MySQL API, see *Note apis-ruby-rubymysql::.  File: manual.info, Node: apis-ruby-mysqlruby, Next: apis-ruby-rubymysql, Prev: apis-ruby, Up: apis-ruby 21.13.1 The MySQL/Ruby API -------------------------- The MySQL/Ruby module provides access to MySQL databases using Ruby through `libmysql'. For information on installing the module, and the functions exposed, see MySQL/Ruby (http://tmtm.org/en/mysql/ruby/).  File: manual.info, Node: apis-ruby-rubymysql, Prev: apis-ruby-mysqlruby, Up: apis-ruby 21.13.2 The Ruby/MySQL API -------------------------- The Ruby/MySQL module provides access to MySQL databases using Ruby through a native driver interface using the MySQL network protocol. For information on installing the module, and the functions exposed, see Ruby/MySQL (http://tmtm.org/en/ruby/mysql/README_en.html).  File: manual.info, Node: apis-tcl, Next: apis-eiffel, Prev: apis-ruby, Up: connectors-apis 21.14 MySQL Tcl API =================== `MySQLtcl' is a simple API for accessing a MySQL database server from the Tcl programming language. It can be found at `http://www.xdobry.de/mysqltcl/'.  File: manual.info, Node: apis-eiffel, Prev: apis-tcl, Up: connectors-apis 21.15 MySQL Eiffel Wrapper ========================== Eiffel MySQL is an interface to the MySQL database server using the Eiffel programming language, written by Michael Ravits. It can be found at `http://efsa.sourceforge.net/archive/ravits/mysql.htm'.  File: manual.info, Node: extending-mysql, Next: mysql-enterprise-monitor, Prev: connectors-apis, Up: Top 22 Extending MySQL ****************** * Menu: * mysql-internals:: MySQL Internals * plugin-api:: The MySQL Plugin API * adding-functions:: Adding New Functions to MySQL * adding-procedures:: Adding New Procedures to MySQL * porting:: Debugging and Porting MySQL  File: manual.info, Node: mysql-internals, Next: plugin-api, Prev: extending-mysql, Up: extending-mysql 22.1 MySQL Internals ==================== * Menu: * mysql-threads:: MySQL Threads * mysql-test-suite:: The MySQL Test Suite This chapter describes a lot of things that you need to know when working on the MySQL code. To track or contribute to MySQL development, follow the instructions in *Note installing-development-tree::. If you are interested in MySQL internals, you should also subscribe to our `internals' mailing list. This list has relatively low traffic. For details on how to subscribe, please see *Note mailing-lists::. Many MySQL developers at Oracle Corporation are on the `internals' list and we help other people who are working on the MySQL code. Feel free to use this list both to ask questions about the code and to send patches that you would like to contribute to the MySQL project!  File: manual.info, Node: mysql-threads, Next: mysql-test-suite, Prev: mysql-internals, Up: mysql-internals 22.1.1 MySQL Threads -------------------- The MySQL server creates the following threads: * Connection manager threads handle client connection requests on the network interfaces that the server listens to. On all platforms, one manager thread handles TCP/IP connection requests. On Unix, this manager thread also handles Unix socket file connection requests. On Windows, a manager thread handles shared-memory connection requests, and another handles named-pipe connection requests. The server does not create threads to handle interfaces that it does not listen to. For example, a Windows server that does not have support for named-pipe connections enabled does not create a thread to handle them. * Connection manager threads associate each client connection with a thread dedicated to it that handles authentication and request processing for that connection. Manager threads create a new thread when necessary but try to avoid doing so by consulting the thread cache first to see whether it contains a thread that can be used for the connection. When a connection ends, its thread is returned to the thread cache if the cache is not full. For information about tuning the parameters that control thread resources, see *Note connection-threads::. * On a master replication server, connections from slave servers are handled like client connections: There is one thread per connected slave. * On a slave replication server, an I/O thread is started to connect to the master server and read updates from it. An SQL thread is started to apply updates read from the master. These two threads run independently and can be started and stopped independently. * A signal thread handles all signals. This thread also normally handles alarms and calls `process_alarm()' to force timeouts on connections that have been idle too long. * If `InnoDB' is used, there will be 4 additional threads by default. Those are file I/O threads, controlled by the `innodb_file_io_threads' parameter. See *Note innodb-parameters::. * If *Note `mysqld': mysqld. is compiled with `-DUSE_ALARM_THREAD', a dedicated thread that handles alarms is created. This is only used on some systems where there are problems with `sigwait()' or if you want to use the `thr_alarm()' code in your application without a dedicated signal handling thread. * If the server is started with the `--flush_time=VAL' option, a dedicated thread is created to flush all tables every VAL seconds. * Each table for which *Note `INSERT DELAYED': insert-delayed. statements are issued gets its own thread. See *Note insert-delayed::. * If the event scheduler is active, there is one thread for the scheduler, and a thread for each event currently running. See *Note events-overview::. *Note `mysqladmin processlist': mysqladmin. only shows the connection, *Note `INSERT DELAYED': insert-delayed, replication, and event threads.  File: manual.info, Node: mysql-test-suite, Prev: mysql-threads, Up: mysql-internals 22.1.2 The MySQL Test Suite --------------------------- The test system that is included in Unix source and binary distributions makes it possible for users and developers to perform regression tests on the MySQL code. These tests can be run on Unix. You can also write your own test cases. For information about the MySQL Test Framework, including system requirements, see the manual available at `http://dev.mysql.com/doc/'. The current set of test cases doesn't test everything in MySQL, but it should catch most obvious bugs in the SQL processing code, operating system or library issues, and is quite thorough in testing replication. Our goal is to have the tests cover 100% of the code. We welcome contributions to our test suite. You may especially want to contribute tests that examine the functionality critical to your system because this ensures that all future MySQL releases work well with your applications. The test system consists of a test language interpreter (`mysqltest'), a Perl script to run all tests (`mysql-test-run.pl'), the actual test cases written in a special test language, and their expected results. To run the test suite on your system after a build, type `make test' from the source root directory, or change location to the `mysql-test' directory and type `./mysql-test-run.pl'. If you have installed a binary distribution, change location to the `mysql-test' directory under the installation root directory (for example, `/usr/local/mysql/mysql-test'), and run `./mysql-test-run.pl'. All tests should succeed. If any do not, feel free to try to find out why and report the problem if it indicates a bug in MySQL. See *Note bug-reports::. If one test fails, you should run `mysql-test-run.pl' with the `--force' option to check whether any other tests fail. If you have a copy of *Note `mysqld': mysqld. running on the machine where you want to run the test suite, you do not have to stop it, as long as it is not using ports `9306' or `9307'. If either of those ports is taken, you should set the `MTR_BUILD_THREAD' environment variable to an appropriate value, and the test suite will use a different set of ports for master, slave, NDB, and Instance Manager). For example: shell> export MTR_BUILD_THREAD=31 shell> ./mysql-test-run.pl [OPTIONS] [TEST_NAME] In the `mysql-test' directory, you can run an individual test case with `./mysql-test-run.pl TEST_NAME'. If you have a question about the test suite, or have a test case to contribute, send an email message to the MySQL `internals' mailing list. See *Note mailing-lists::. This list does not accept attachments, so you should FTP all the relevant files to: `ftp://ftp.mysql.com/pub/mysql/upload/'  File: manual.info, Node: plugin-api, Next: adding-functions, Prev: mysql-internals, Up: extending-mysql 22.2 The MySQL Plugin API ========================= * Menu: * plugin-api-characteristics:: Plugin API Characteristics * plugin-api-components:: Plugin API Components * plugin-types:: Types of Plugins * writing-plugins:: Writing Plugins MySQL 5.1 and up supports a plugin API that enables creation of server components. Plugins can be loaded at server startup, or loaded and unloaded at runtime without restarting the server. The API is generic and does not specify what plugins can do. The components supported by this interface include, but are not limited to, storage engines, full-text parser plugins, partitioning support, and server extensions. For example, full-text parser plugins can be used to replace or augment the built-in full-text parser. A plugin can parse text into words using rules that differ from those used by the built-in parser. This can be useful if you need to parse text with characteristics different from those expected by the built-in parser. The plugin interface is intended as the successor to the older user-defined function (UDF) interface. The plugin interface uses the `plugin' table in the `mysql' database to record information about plugins that have been installed permanently with the *Note `INSTALL PLUGIN': install-plugin. statement. This table is created as part of the MySQL installation process. (If you are upgrading from a version of MySQL older than 5.1, you should run the *Note `mysql_upgrade': mysql-upgrade. command to create this table. See *Note mysql-upgrade::.) Plugins can also be installed for a single server invocation with the `--plugin-load' option. Plugins installed this way are not recorded in the `plugin' table. See *Note server-plugin-loading::. * Additional Resources * The book `MySQL 5.1 Plugin Development' by Sergei Golubchik and Andrew Hutchings provides a wealth of detail about the plugin API. Despite the title says 5.1, most of the information applies to later versions as well.  File: manual.info, Node: plugin-api-characteristics, Next: plugin-api-components, Prev: plugin-api, Up: plugin-api 22.2.1 Plugin API Characteristics --------------------------------- The server plugin API has these characteristics: * All plugins have several things in common. Each plugin has a name that it can be referred to in SQL statements, as well as other metadata such as an author and a description that provide other information. This information can be examined in the *Note `INFORMATION_SCHEMA.PLUGINS': plugins-table. table or using the *Note `SHOW PLUGINS': show-plugins. statement. * The plugin framework is extendable to accommodate different kinds of plugins. Although some aspects of the plugin API are common to all types of plugins, the API also permits type-specific interface elements so that different types of plugins can be created. A plugin with one purpose can have an interface most appropriate to its own requirements and not the requirements of some other plugin type. Interfaces for several types of plugins exist, such as storage engines, full-text parser, and `INFORMATION_SCHEMA' tables. Others can be added. * Plugins can expose information to users. A plugin can implement system and status variables that are available through the *Note `SHOW VARIABLES': show-variables. and *Note `SHOW STATUS': show-status. statements. * The plugin API includes versioning information. The version information included in the plugin API enables a plugin library and each plugin that it contains to be self-identifying with respect to the API version that was used to build the library. If the API changes over time, the version numbers will change, but a server can examine a given plugin library's version information to determine whether it supports the plugins in the library. There are two types of version numbers. The first is the version for the general plugin framework itself. Each plugin library includes this kind of version number. The second type of version applies to individual plugins. Each specific type of plugin has a version for its interface, so each plugin in a library has a type-specific version number. For example, a library containing a full-text parser plugin has a general plugin API version number, and the plugin has a version number specific to the full-text plugin interface. * The plugin API implements security restrictions. A plugin library must be installed in a specific dedicated directory for which the location is controlled by the server and cannot be changed at runtime. Also, the library must contain specific symbols that identify it as a plugin library. The server will not load something as a plugin if it was not built as a plugin. In some respects, the server plugin API is similar to the older user-defined function (UDF) API that it supersedes, but the plugin API has several advantages over the older interface. For example, UDFs had no versioning information. Also, the newer plugin interface eliminates the security issues of the older UDF interface. The older interface for writing nonplugin UDFs permitted libraries to be loaded from any directory searched by the system's dynamic linker, and the symbols that identified the UDF library were relatively nonspecific.  File: manual.info, Node: plugin-api-components, Next: plugin-types, Prev: plugin-api-characteristics, Up: plugin-api 22.2.2 Plugin API Components ---------------------------- The server plugin implementation comprises several components. SQL statements: * *Note `INSTALL PLUGIN': install-plugin. registers a plugin in the `mysql.plugin' table and loads the plugin code. * *Note `UNINSTALL PLUGIN': uninstall-plugin. unregisters a plugin from the `mysql.plugin' table and unloads the plugin code. * The `WITH PARSER' clause for full-text index creation associates a full-text parser plugin with a given `FULLTEXT' index. * *Note `SHOW PLUGINS': show-plugins. displays information about server plugins. Command-line options and system variables: * The `--plugin-load' option enables plugins to be loaded at server startup time. * The `plugin_dir' system variable indicates the location of the directory where all plugins must be installed. The value of this variable can be specified at server startup with a `--plugin_dir=PATH' option. *Note `mysql_config --plugindir': mysql-config. displays the default plugin directory path name. For additional information about plugin loading, see *Note server-plugin-loading::. Plugin-related tables: * The *Note `INFORMATION_SCHEMA.PLUGINS': plugins-table. table contains plugin information. * The `mysql.plugin' table lists each plugin that was installed with *Note `INSTALL PLUGIN': install-plugin. and is required for plugin use. For new MySQL installations, this table is created during the installation process. If you are upgrading from a version of MySQL older than 5.1, you should run *Note `mysql_upgrade': mysql-upgrade. to update your system tables and create the `plugin' table (see *Note mysql-upgrade::). Source files (the locations indicate where the files are found in MySQL source distributions): * In the `include/mysql' directory, `plugin.h' exposes the public plugin API. This file should be examined by anyone who wants to write a plugin library. `plugin_XXX.h' files provide additional information that pertains to specific types of plugins. * In the `sql' directory, `sql_plugin.h' and `sql_plugin.cc' comprise the internal plugin implementation. These files need not be consulted by plugin developers. They may be of interest for those who want to know more about how the server handles plugins.  File: manual.info, Node: plugin-types, Next: writing-plugins, Prev: plugin-api-components, Up: plugin-api 22.2.3 Types of Plugins ----------------------- * Menu: * storage-engine-plugins:: Storage Engine Plugins * full-text-plugins:: Full-Text Parser Plugins * daemon-plugins:: Daemon Plugins * information-schema-plugins:: `INFORMATION_SCHEMA' Plugins The plugin API enables creation of plugins that implement several capabilities: * Storage engines * Full-text parsers * Daemons * `INFORMATION_SCHEMA' tables The following sections provide an overview of these plugin types.  File: manual.info, Node: storage-engine-plugins, Next: full-text-plugins, Prev: plugin-types, Up: plugin-types 22.2.3.1 Storage Engine Plugins ............................... The pluggable storage engine architecture used by MySQL Server enables storage engines to be written as plugins and loaded into and unloaded from a running server. For a description of this architecture, see *Note pluggable-storage-overview::. For information on how to use the plugin API to write storage engines, see MySQL Internals: Custom Engine (http://forge.mysql.com/wiki/MySQL_Internals_Custom_Engine).  File: manual.info, Node: full-text-plugins, Next: daemon-plugins, Prev: storage-engine-plugins, Up: plugin-types 22.2.3.2 Full-Text Parser Plugins ................................. MySQL has a built-in parser that it uses by default for full-text operations (parsing text to be indexed, or parsing a query string to determine the terms to be used for a search). For full-text processing, `parsing' means extracting words from text or a query string based on rules that define which character sequences make up a word and where word boundaries lie. When parsing for indexing purposes, the parser passes each word to the server, which adds it to a full-text index. When parsing a query string, the parser passes each word to the server, which accumulates the words for use in a search. The parsing properties of the built-in full-text parser are described in *Note fulltext-search::. These properties include rules for determining how to extract words from text. The parser is influenced by certain system variables such as `ft_min_word_len' and `ft_max_word_len' that cause words shorter or longer to be excluded, and by the stopword list that identifies common words to be ignored. The plugin API enables you to provide a full-text parser of your own so that you have control over the basic duties of a parser. A parser plugin can operate in either of two roles: * The plugin can replace the built-in parser. In this role, the plugin reads the input to be parsed, splits it up into words, and passes the words to the server (either for indexing or for word accumulation). One reason to use a parser this way is that you need to use different rules from those of the built-in parser for determining how to split up input into words. For example, the built-in parser considers the text `case-sensitive' to consist of two words `case' and `sensitive,' whereas an application might need to treat the text as a single word. * The plugin can act in conjunction with the built-in parser by serving as a front end for it. In this role, the plugin extracts text from the input and passes the text to the parser, which splits up the text into words using its normal parsing rules. In particular, this parsing will be affected by the `ft_XXX' system variables and the stopword list. One reason to use a parser this way is that you need to index content such as PDF documents, XML documents, or `.doc' files. The built-in parser is not intended for those types of input but a plugin can pull out the text from these input sources and pass it to the built-in parser. It is also possible for a parser plugin to operate in both roles. That is, it could extract text from nonplaintext input (the front end role), and also parse the text into words (thus replacing the built-in parser). A full-text plugin is associated with full-text indexes on a per-index basis. That is, when you install a parser plugin initially, that does not cause it to be used for any full-text operations. It simply becomes available. For example, a full-text parser plugin becomes available to be named in a `WITH PARSER' clause when creating individual `FULLTEXT' indexes. To create such an index at table-creation time, do this: CREATE TABLE t ( doc CHAR(255), FULLTEXT INDEX (doc) WITH PARSER my_parser ) ENGINE=MyISAM; Or you can add the index after the table has been created: ALTER TABLE t ADD FULLTEXT INDEX (doc) WITH PARSER my_parser; The only SQL change for associating the parser with the index is the `WITH PARSER' clause. Searches are specified as before, with no changes needed for queries. When you associate a parser plugin with a `FULLTEXT' index, the plugin is required for using the index. If the parser plugin is dropped, any index associated with it becomes unusable. Any attempt to use it a table for which a plugin is not available results in an error, although *Note `DROP TABLE': drop-table. is still possible. For more information about full-text plugins, see *Note writing-full-text-plugins::.  File: manual.info, Node: daemon-plugins, Next: information-schema-plugins, Prev: full-text-plugins, Up: plugin-types 22.2.3.3 Daemon Plugins ....................... A daemon plugin is a simple type of plugin used for code that should be run by the server but that does not communicate with it. MySQL distributions include an example daemon plugin that writes periodic heartbeat messages to a file. For more information about daemon plugins, see *Note writing-daemon-plugins::.  File: manual.info, Node: information-schema-plugins, Prev: daemon-plugins, Up: plugin-types 22.2.3.4 `INFORMATION_SCHEMA' Plugins ..................................... `INFORMATION_SCHEMA' plugins enable the creation of tables containing server metadata that are exposed to users through the `INFORMATION_SCHEMA' database. For example, `InnoDB' uses `INFORMATION_SCHEMA' plugins to provide tables that contain information about current transactions and locks.  File: manual.info, Node: writing-plugins, Prev: plugin-types, Up: plugin-api 22.2.4 Writing Plugins ---------------------- * Menu: * writing-plugins-overview:: Overview of Plugin Writing * plugin-data-structures:: Plugin Data Structures * compiling-plugin-libraries:: Compiling and Installing Plugin Libraries * writing-full-text-plugins:: Writing Full-Text Parser Plugins * writing-daemon-plugins:: Writing Daemon Plugins To create a plugin library, you must provide the required descriptor information that indicates what plugins the library file contains, and write the interface functions for each plugin. Every server plugin must have a general descriptor that provides information to the plugin API, and a type-specific descriptor that provides information about the plugin interface for a given type of plugin. The structure of the general descriptor is the same for all plugin types. The structure of the type-specific descriptor varies among plugin types and is determined by the requirements of what the plugin needs to do. The server plugin interface also enables plugins to expose status and system variables. These variables become visible through the *Note `SHOW STATUS': show-status. and *Note `SHOW VARIABLES': show-variables. statements and the corresponding `INFORMATION_SCHEMA' tables. You can write plugins in C or C++ (or another language that can use C calling conventions). Plugins are loaded and unloaded dynamically, so your operating system must support dynamic loading and you must have compiled *Note `mysqld': mysqld. dynamically (not statically). A server plugin contains code that becomes part of the running server, so when you write the plugin, you are bound by any and all constraints that otherwise apply to writing server code. For example, you may have problems if you attempt to use functions from the `libstdc++' library. These constraints may change in future versions of the server, so it is possible that server upgrades will require revisions to plugins originally written for older servers. For information about these constraints, see *Note source-configuration-options::, and *Note compilation-problems::.  File: manual.info, Node: writing-plugins-overview, Next: plugin-data-structures, Prev: writing-plugins, Up: writing-plugins 22.2.4.1 Overview of Plugin Writing ................................... The following procedure provides an overview of the steps needed to create a plugin library. The next sections provide additional details on setting plugin data structures and writing specific types of plugins. 1. In the plugin source file, include the header files that the plugin library needs. The `plugin.h' file is required, and the library might require other files as well. For example: #include #include #include 2. Set up the descriptor information for the plugin library file. This descriptor must contain the general plugin descriptor for each server plugin in the file. For more information, see *Note server-plugin-descriptors::. In addition, set up the type-specific descriptor for each server plugin in the library. Each plugin's general descriptor points to its type-specific descriptor. 3. Write the plugin interface functions for each plugin. Each plugin's general plugin descriptor points to the initialization and deinitialization functions that the server should invoke when it loads and unloads the plugin. The plugin's type-specific description may also point to interface functions. 4. Set up the status and system variables, if there are any. 5. Compile the plugin library as a shared library and install it in the plugin directory. For more information, see *Note compiling-plugin-libraries::. 6. Register the plugin with the server. For more information, see *Note server-plugin-loading::. 7. Test the plugin to verify that it works properly.  File: manual.info, Node: plugin-data-structures, Next: compiling-plugin-libraries, Prev: writing-plugins-overview, Up: writing-plugins 22.2.4.2 Plugin Data Structures ............................... * Menu: * server-plugin-descriptors:: Library and Plugin Descriptors * plugin-status-system-variables:: Plugin Status and System Variables A plugin library file includes descriptor information to indicate what plugins it contains. The plugin library must include the following descriptor information: * A library descriptor indicates the general server plugin API version number used by the library and contains a general plugin descriptor for each server plugin in the library. To provide the framework for this descriptor, invoke two macros from the `plugin.h' header file: mysql_declare_plugin(NAME) ... ONE OR MORE SERVER PLUGIN DESCRIPTORS HERE ... mysql_declare_plugin_end; The macros expand to provide a declaration for the API version automatically. You must provide the plugin descriptors. * Within the library descriptor, each general server plugin is described by a `st_mysql_plugin' structure. This plugin descriptor structure contains information that is common to every type of server plugin: A value that indicates the plugin type; the plugin name, author, description, and license type; pointers to the initialization and deinitialization functions that the server invokes when it loads and unloads the plugin, and pointers to any status or system variables the plugin implements. * Each general server plugin descriptor within the library descriptor also contains a pointer to a type-specific plugin descriptor. The structure of the type-specific descriptors varies from one plugin type to another because each type of plugin can have its own API. A type-specific plugin descriptor contains a type-specific API version number and pointers to the functions that are needed to implement that plugin type. For example, a full-text parser plugin has initialization and deinitialization functions, and a main parsing function. The server invokes these functions when it uses the plugin to parse text. The plugin library also contains the interface functions that are referenced by the general and type-specific descriptors for each plugin in the library.  File: manual.info, Node: server-plugin-descriptors, Next: plugin-status-system-variables, Prev: plugin-data-structures, Up: plugin-data-structures 22.2.4.3 Library and Plugin Descriptors ....................................... Every plugin library must include a library descriptor that contains the general plugin descriptor for each server plugin in the file. This section discusses how to write the library and general descriptors for server plugins. The library descriptor must define two symbols: * `_mysql_plugin_interface_version_' specifies the version number of the general plugin framework. This is given by the `MYSQL_PLUGIN_INTERFACE_VERSION' symbol, which is defined in the `plugin.h' file. * `_mysql_plugin_declarations_' defines an array of plugin declarations, terminated by a declaration with all members set to 0. Each declaration is an instance of the `st_mysql_plugin' structure (also defined in `plugin.h'). There must be one of these for each server plugin in the library. If the server does not find those two symbols in a library, it does not accept it as a legal plugin library and rejects it with an error. This prevents use of a library for plugin purposes unless it was built specifically as a plugin library. The conventional way to define the two required symbols is by using the `mysql_declare_plugin()' and `mysql_declare_plugin_end' macros from the `plugin.h' file: mysql_declare_plugin(NAME) ... ONE OR MORE SERVER PLUGIN DESCRIPTORS HERE ... mysql_declare_plugin_end; Each server plugin must have a general descriptor that provides information to the server plugin API. The general descriptor has the same structure for all plugin types. The `st_mysql_plugin' structure in the `plugin.h' file defines this descriptor: struct st_mysql_plugin { int type; /* the plugin type (a MYSQL_XXX_PLUGIN value) */ void *info; /* pointer to type-specific plugin descriptor */ const char *name; /* plugin name */ const char *author; /* plugin author (for SHOW PLUGINS) */ const char *descr; /* general descriptive text (for SHOW PLUGINS ) */ int license; /* the plugin license (PLUGIN_LICENSE_XXX) */ int (*init)(void *); /* the function to invoke when plugin is loaded */ int (*deinit)(void *);/* the function to invoke when plugin is unloaded */ unsigned int version; /* plugin version (for SHOW PLUGINS) */ struct st_mysql_show_var *status_vars; struct st_mysql_sys_var **system_vars; void * __reserved1; /* reserved for dependency checking */ }; The `st_mysql_plugin' descriptor structure members are used as follows. `char *' members should be specified as null-terminated strings. * `type': The plugin type. This must be one of the plugin-type values from `plugin.h': /* The allowable types of plugins */ #define MYSQL_UDF_PLUGIN 0 /* User-defined function */ #define MYSQL_STORAGE_ENGINE_PLUGIN 1 /* Storage Engine */ #define MYSQL_FTPARSER_PLUGIN 2 /* Full-text parser plugin */ #define MYSQL_DAEMON_PLUGIN 3 /* The daemon/raw plugin type */ #define MYSQL_INFORMATION_SCHEMA_PLUGIN 4 /* The I_S plugin type */ ... For example, for a full-text parser plugin, the `type' value is `MYSQL_FTPARSER_PLUGIN'. * `info': A pointer to the type-specific descriptor for the plugin. This descriptor's structure depends on the particular type of plugin, unlike that of the general plugin descriptor structure. For version-control purposes, the first member of the type-specific descriptor for every plugin type is expected to be the interface version for the type. This enables the server to check the type-specific version for every plugin no matter its type. Following the version number, the descriptor includes any other members needed, such as callback functions and other information needed by the server to invoke the plugin properly. Later sections on writing particular types of server plugins describe the structure of their type-specific descriptors. * `name': A string that gives the plugin name. This is the name that will be listed in the `mysql.plugin' table and by which you refer to the plugin in SQL statements such as *Note `INSTALL PLUGIN': install-plugin. and *Note `UNINSTALL PLUGIN': uninstall-plugin, or with the `--plugin-load' option. The name is also visible in the *Note `INFORMATION_SCHEMA.PLUGINS': plugins-table. table or the output from *Note `SHOW PLUGINS': show-plugins. * `author': A string naming the plugin author. This can be whatever you like. * `desc': A string that provides a general description of the plugin. This can be whatever you like. * `license': The plugin license type. The value can be one of `PLUGIN_LICENSE_PROPRIETARY', `PLUGIN_LICENSE_GPL', or `PLUGIN_LICENSE_BSD'. * `init': A once-only initialization function, or `NULL' if there is no such function. The server executes this function when it loads the plugin, which happens for *Note `INSTALL PLUGIN': install-plugin. or, for plugins listed in the `mysql.plugin' table, at server startup. The function takes one argument that points to the internal structure used to identify the plugin. It returns zero for success and nonzero for failure. * `deinit': A once-only deinitialization function, or `NULL' if there is no such function. The server executes this function when it unloads the plugin, which happens for *Note `UNINSTALL PLUGIN': uninstall-plugin. or, for plugins listed in the `mysql.plugin' table, at server shutdown. The function takes one argument that points to the internal structure used to identify the plugin It returns zero for success and nonzero for failure. * `version': The plugin version number. When the plugin is installed, this value can be retrieved from the *Note `INFORMATION_SCHEMA.PLUGINS': plugins-table. table. The value includes major and minor numbers. If you write the value as a hex constant, the format is `0xMMNN', where MM and `NN' are the major and minor numbers, respectively. For example, `0x0302' represents version 3.2. * `status_vars': A pointer to a structure for status variables associated with the plugin, or `NULL' if there are no such variables. When the plugin is installed, these variables are displayed in the output of the *Note `SHOW STATUS': show-status. statement. The `status_vars' member, if not `NULL', points to an array of `st_mysql_show_var' structures that describe status variables. See *Note plugin-status-system-variables::. * `system_vars': A pointer to a structure for system variables associated with the plugin, or `NULL' if there are no such variables. These options and system variables can be used to help initialize variables within the plugin. The `system_vars' member, if not `NULL', points to an array of `st_mysql_sys_var' structures that describe system variables. See *Note plugin-status-system-variables::. * `__reserved1': A placeholder for the future. Currently, it should be set to `NULL'. The server invokes the `init' and `deinit' functions in the general plugin descriptor only when loading and unloading the plugin. They have nothing to do with use of the plugin such as happens when an SQL statement causes the plugin to be invoked. For example, the descriptor information for a library that contains a single full-text parser plugin named `simple_parser' looks like this: mysql_declare_plugin(ftexample) { MYSQL_FTPARSER_PLUGIN, /* type */ &simple_parser_descriptor, /* descriptor */ "simple_parser", /* name */ "Oracle Corporation", /* author */ "Simple Full-Text Parser", /* description */ PLUGIN_LICENSE_GPL, /* plugin license */ simple_parser_plugin_init, /* init function (when loaded) */ simple_parser_plugin_deinit,/* deinit function (when unloaded) */ 0x0001, /* version */ simple_status, /* status variables */ simple_system_variables, /* system variables */ NULL } mysql_declare_plugin_end; For a full-text parser plugin, the type must be `MYSQL_FTPARSER_PLUGIN'. This is the value that identifies the plugin as being legal for use in a `WITH PARSER' clause when creating a `FULLTEXT' index. (No other plugin type is legal for this clause.) `plugin.h' defines the `mysql_declare_plugin()' and `mysql_declare_plugin_end' macros like this: #ifndef MYSQL_DYNAMIC_PLUGIN #define __MYSQL_DECLARE_PLUGIN(NAME, VERSION, PSIZE, DECLS) \ int VERSION= MYSQL_PLUGIN_INTERFACE_VERSION; \ int PSIZE= sizeof(struct st_mysql_plugin); \ struct st_mysql_plugin DECLS[]= { #else #define __MYSQL_DECLARE_PLUGIN(NAME, VERSION, PSIZE, DECLS) \ MYSQL_PLUGIN_EXPORT int _mysql_plugin_interface_version_= MYSQL_PLUGIN_INTERFACE_VERSION; \ MYSQL_PLUGIN_EXPORT int _mysql_sizeof_struct_st_plugin_= sizeof(struct st_mysql_plugin); \ MYSQL_PLUGIN_EXPORT struct st_mysql_plugin _mysql_plugin_declarations_[]= { #endif #define mysql_declare_plugin(NAME) \ __MYSQL_DECLARE_PLUGIN(NAME, \ builtin_ ## NAME ## _plugin_interface_version, \ builtin_ ## NAME ## _sizeof_struct_st_plugin, \ builtin_ ## NAME ## _plugin) #define mysql_declare_plugin_end ,{0,0,0,0,0,0,0,0,0,0,0,0}} *Note*: Those declarations define the `_mysql_plugin_interface_version_' symbol only if the `MYSQL_DYNAMIC_PLUGIN' symbol is defined. This means that `-DMYSQL_DYNAMIC_PLUGIN' must be provided as part of the compilation command to build the plugin as a shared library. When the macros are used as just shown, they expand to the following code, which defines both of the required symbols (`_mysql_plugin_interface_version_' and `_mysql_plugin_declarations_'): int _mysql_plugin_interface_version_= MYSQL_PLUGIN_INTERFACE_VERSION; int _mysql_sizeof_struct_st_plugin_= sizeof(struct st_mysql_plugin); struct st_mysql_plugin _mysql_plugin_declarations_[]= { { MYSQL_FTPARSER_PLUGIN, /* type */ &simple_parser_descriptor, /* descriptor */ "simple_parser", /* name */ "Oracle Corporation", /* author */ "Simple Full-Text Parser", /* description */ PLUGIN_LICENSE_GPL, /* plugin license */ simple_parser_plugin_init, /* init function (when loaded) */ simple_parser_plugin_deinit,/* deinit function (when unloaded) */ 0x0001, /* version */ simple_status, /* status variables */ simple_system_variables, /* system variables */ NULL } ,{0,0,0,0,0,0,0,0,0,0,0,0}} }; The preceding example declares a single plugin in the general descriptor, but it is possible to declare multiple plugins. List the declarations one after the other between `mysql_declare_plugin()' and `mysql_declare_plugin_end', separated by commas. MySQL server plugins can be written in C or C++ (or another language that can use C calling conventions). If you write a C++ plugin, one C++ feature that you should not use is nonconstant variables to initialize global structures. Members of structures such as the `st_mysql_plugin' structure should be initialized only with constant variables. The `simple_parser' descriptor shown earlier is permissible in a C++ plugin because it satisfies that requirement: mysql_declare_plugin(ftexample) { MYSQL_FTPARSER_PLUGIN, /* type */ &simple_parser_descriptor, /* descriptor */ "simple_parser", /* name */ "Oracle Corporation", /* author */ "Simple Full-Text Parser", /* description */ PLUGIN_LICENSE_GPL, /* plugin license */ simple_parser_plugin_init, /* init function (when loaded) */ simple_parser_plugin_deinit,/* deinit function (when unloaded) */ 0x0001, /* version */ simple_status, /* status variables */ simple_system_variables, /* system variables */ NULL } mysql_declare_plugin_end; Here is another valid way to write the general descriptor. It uses constant variables to indicate the plugin name, author, and description: const char *simple_parser_name = "simple_parser"; const char *simple_parser_author = "Oracle Corporation"; const char *simple_parser_description = "Simple Full-Text Parser"; mysql_declare_plugin(ftexample) { MYSQL_FTPARSER_PLUGIN, /* type */ &simple_parser_descriptor, /* descriptor */ simple_parser_name, /* name */ simple_parser_author, /* author */ simple_parser_description, /* description */ PLUGIN_LICENSE_GPL, /* plugin license */ simple_parser_plugin_init, /* init function (when loaded) */ simple_parser_plugin_deinit,/* deinit function (when unloaded) */ 0x0001, /* version */ simple_status, /* status variables */ simple_system_variables, /* system variables */ NULL } mysql_declare_plugin_end; However, the following general descriptor is invalid. It uses structure members to indicate the plugin name, author, and description, but structures are not considered constant initializers in C++: typedef struct { const char *name; const char *author; const char *description; } plugin_info; plugin_info parser_info = { "simple_parser", "Oracle Corporation", "Simple Full-Text Parser" }; mysql_declare_plugin(ftexample) { MYSQL_FTPARSER_PLUGIN, /* type */ &simple_parser_descriptor, /* descriptor */ parser_info.name, /* name */ parser_info.author, /* author */ parser_info.description, /* description */ PLUGIN_LICENSE_GPL, /* plugin license */ simple_parser_plugin_init, /* init function (when loaded) */ simple_parser_plugin_deinit,/* deinit function (when unloaded) */ 0x0001, /* version */ simple_status, /* status variables */ simple_system_variables, /* system variables */ NULL } mysql_declare_plugin_end;  File: manual.info, Node: plugin-status-system-variables, Prev: server-plugin-descriptors, Up: plugin-data-structures 22.2.4.4 Plugin Status and System Variables ........................................... The server plugin interface enables plugins to expose status and system variables using the `status_vars' and `system_vars' members of the general plugin descriptor. The `status_vars' member of the general plugin descriptor, if not 0, points to an array of `st_mysql_show_var' structures, each of which describes one status variable, followed by a structure with all members set to 0. The `st_mysql_show_var' structure has this definition: struct st_mysql_show_var { const char *name; char *value; enum enum_mysql_show_type type; }; When the plugin is installed, the plugin name and the `name' value are joined with an underscore to form the name displayed by *Note `SHOW STATUS': show-status. The following table shows the permissible status variable `type' values and what the corresponding variable should be. *Server Plugin Status Variable Types* Variable Type Meaning `SHOW_BOOL' Pointer to a boolean variable `SHOW_INT' Pointer to an integer variable `SHOW_LONG' Pointer to a long integer variable `SHOW_LONGLONG' Pointer to a longlong integer variable `SHOW_CHAR' A string `SHOW_CHAR_PTR' Pointer to a string `SHOW_ARRAY' Pointer to another `st_mysql_show_var' array `SHOW_FUNC' Pointer to a function `SHOW_DOUBLE' Pointer to a double For the `SHOW_FUNC' type, the function is called and fills in its `out' parameter, which then provides information about the variable to be displayed. The function has this signature: #define SHOW_VAR_FUNC_BUFF_SIZE 1024 typedef int (*mysql_show_var_func) (void *thd, struct st_mysql_show_var *out, char *buf); The `system_vars' member, if not 0, points to an array of `st_mysql_sys_var' structures, each of which describes one system variable (which can also be set from the command-line or configuration file), followed by a structure with all members set to 0. The `st_mysql_sys_var' structure is defined as follows: struct st_mysql_sys_var { int flags; const char *name, *comment; int (*check)(THD*, struct st_mysql_sys_var *, void*, st_mysql_value*); void (*update)(THD*, struct st_mysql_sys_var *, void*, const void*); }; Additional fields are append as required depending upon the flags. For convenience, a number of macros are defined that make creating new system variables within a plugin much simpler. Throughout the macros, the following fields are available: * `name': An unquoted identifier for the system variable. * `varname': The identifier for the static variable. Where not available, it is the same as the `name' field. * `opt': Additional use flags for the system variable. The following table shows the permissible flags. *Server Plugin System Variable Flags* Flag Value Description `PLUGIN_VAR_READONLY'The system variable is read only `PLUGIN_VAR_NOSYSVAR'The system variable is not user visible at runtime `PLUGIN_VAR_NOCMDOPT'The system variable is not configurable from the command line `PLUGIN_VAR_NOCMDARG'No argument is required at the command line (typically used for boolean variables) `PLUGIN_VAR_RQCMDARG'An argument is required at the command line (this is the default) ` An argument is optional at the command line PLUGIN_VAR_OPCMDARG' `PLUGIN_VAR_MEMALLOC'Used for string variables; indicates that memory is to be allocated for storage of the string * `comment': A descriptive comment to be displayed in the server help message. `NULL' if this variable is to be hidden. * `check': The check function, `NULL' for default. * `update': The update function, `NULL' for default. * `default': The variable default value. * `minimum': The variable minimum value. * `maximum': The variable maximum value. * `blocksize': The variable block size. When the value is set, it is rounded to the nearest multiple of `blocksize'. A system variable may be accessed either by using the static variable directly or by using the `SYSVAR()'accessor macro. The `SYSVAR()' macro is provided for completeness. Usually it should be used only when the code cannot directly access the underlying variable. For example: static int my_foo; static MYSQL_SYSVAR_INT(foo_var, my_foo, PLUGIN_VAR_RQCMDARG, "foo comment", NULL, NULL, 0, 0, INT_MAX, 0); ... SYSVAR(foo_var)= value; value= SYSVAR(foo_var); my_foo= value; value= my_foo; Session variables may be accessed only through the `THDVAR()' accessor macro. For example: static MYSQL_THDVAR_BOOL(some_flag, PLUGIN_VAR_NOCMDARG, "flag comment", NULL, NULL, FALSE); ... if (THDVAR(thd, some_flag)) { do_something(); THDVAR(thd, some_flag)= FALSE; } All global and session system variables must be published to *Note `mysqld': mysqld. before use. This is done by constructing a `NULL'-terminated array of the variables and linking to it in the plugin public interface. For example: static struct st_mysql_sys_var *my_plugin_vars[]= { MYSQL_SYSVAR(my_foo), MYSQL_SYSVAR(some_flag), NULL }; mysql_declare_plugin(fooplug) { MYSQL_..._PLUGIN, &plugin_data, "fooplug", "foo author", "This does foo!", PLUGIN_LICENSE_GPL, foo_init, foo_fini, 0x0001, NULL, my_plugin_vars, NULL } mysql_declare_plugin_end; The following convenience macros enable you to declare different types of system variables: * Boolean system variables of type `my_bool', which is a 1-byte boolean. (0 = FALSE, 1 = TRUE) MYSQL_THDVAR_BOOL(name, opt, comment, check, update, default) MYSQL_SYSVAR_BOOL(name, varname, opt, comment, check, update, default) * String system variables of type `char*', which is a pointer to a null-terminated string. MYSQL_THDVAR_STR(name, opt, comment, check, update, default) MYSQL_SYSVAR_STR(name, varname, opt, comment, check, update, default) * Integer system variables, of which there are several varieties. * An `int' system variable, which is typically a 4-byte signed word. MYSQL_THDVAR_INT(name, opt, comment, check, update, default, min, max, blk) MYSQL_SYSVAR_INT(name, varname, opt, comment, check, update, default, minimum, maximum, blocksize) * An `unsigned int' system variable, which is typically a 4-byte unsigned word. MYSQL_THDVAR_UINT(name, opt, comment, check, update, default, min, max, blk) MYSQL_SYSVAR_UINT(name, varname, opt, comment, check, update, default, minimum, maximum, blocksize) * A `long' system variable, which is typically either a 4- or 8-byte signed word. MYSQL_THDVAR_LONG(name, opt, comment, check, update, default, min, max, blk) MYSQL_SYSVAR_LONG(name, varname, opt, comment, check, update, default, minimum, maximum, blocksize) * An `unsigned long' system variable, which is typically either a 4- or 8-byte unsigned word. MYSQL_THDVAR_ULONG(name, opt, comment, check, update, default, min, max, blk) MYSQL_SYSVAR_ULONG(name, varname, opt, comment, check, update, default, minimum, maximum, blocksize) * A `long long' system variable, which is typically an 8-byte signed word. MYSQL_THDVAR_LONGLONG(name, opt, comment, check, update, default, minimum, maximum, blocksize) MYSQL_SYSVAR_LONGLONG(name, varname, opt, comment, check, update, default, minimum, maximum, blocksize) * An `unsigned long long' system variable, which is typically an 8-byte unsigned word. MYSQL_THDVAR_ULONGLONG(name, opt, comment, check, update, default, minimum, maximum, blocksize) MYSQL_SYSVAR_ULONGLONG(name, varname, opt, comment, check, update, default, minimum, maximum, blocksize) * An `unsigned long' system variable, which is typically either a 4- or 8-byte unsigned word. The range of possible values is an ordinal of the number of elements in the `typelib', starting from 0. MYSQL_THDVAR_ENUM(name, opt, comment, check, update, default, typelib) MYSQL_SYSVAR_ENUM(name, varname, opt, comment, check, update, default, typelib) * An `unsigned long long' system variable, which is typically an 8-byte unsigned word. Each bit represents an element in the `typelib'. MYSQL_THDVAR_SET(name, opt, comment, check, update, default, typelib) MYSQL_SYSVAR_SET(name, varname, opt, comment, check, update, default, typelib) Internally, all mutable and plugin system variables are stored in a `HASH' structure. Display of the server command-line help text is handled by compiling a `DYNAMIC_ARRAY' of all variables relevant to command-line options, sorting them, and then iterating through them to display each option. When a command-line option has been handled, it is then removed from the `argv' by the `handle_option()' function (`my_getopt.c'); in effect, it is consumed. The server processes command-line options during the plugin installation process, immediately after the plugin has been successfully loaded but before the plugin initialization function has been called Plugins loaded at runtime do not benefit from any configuration options and must have usable defaults. Once they are installed, they are loaded at *Note `mysqld': mysqld. initialization time and configuration options can be set at the command line or within `my.cnf'. Plugins should consider the `thd' parameter to be read only.  File: manual.info, Node: compiling-plugin-libraries, Next: writing-full-text-plugins, Prev: plugin-data-structures, Up: writing-plugins 22.2.4.5 Compiling and Installing Plugin Libraries .................................................. After your plugin is written, you must compile it and install it. The procedure for compiling shared objects varies from system to system. If you build your library using the GNU autotools, `libtool' should be able to generate the correct compilation commands for your system. If the library is named `somepluglib', you should end up with a shared object file that has a name something like `somepluglib.so'. (The file name might have a different extension on your system.) To use the autotools, you'll need to make a few changes to the configuration files at this point to enable the plugin to be compiled and installed. Assume that your MySQL distribution is installed at a base directory of `/usr/local/mysql' and that its header files are located in the `include' directory under the base directory. Edit `Makefile.am', which should look something like this: #Makefile.am example for a plugin pkgplugindir=$(libdir)/mysql/plugin INCLUDES= -I$(top_builddir)/include -I$(top_srcdir)/include #noinst_LTLIBRARIES= somepluglib.la pkgplugin_LTLIBRARIES= somepluglib.la somepluglib_la_SOURCES= plugin_example.c somepluglib_la_LDFLAGS= -module -rpath $(pkgplugindir) somepluglib_la_CFLAGS= -DMYSQL_DYNAMIC_PLUGIN *Note*: As mentioned in *Note server-plugin-descriptors::, be sure to specify `-DMYSQL_DYNAMIC_PLUGIN' as part of the compilation command when you build the plugin. The `somepluglib_la_CFLAGS' line takes care of this. Adjust the `INCLUDES' line to specify the path name to the installed MySQL header files. Edit it to look like this: INCLUDES= -I/usr/local/mysql/include Make sure that the `noinst_LTLIBRARIES' line is commented out or remove it. Make sure that the `pkglib_LTLIBRARIES' line is not commented out; it enables the `make install' command. Set up the files needed for the `configure' command, invoke it, and run `make': shell> autoreconf --force --install --symlink shell> ./configure --prefix=/usr/local/mysql shell> make The `--prefix' option to `configure' indicates the MySQL base directory under which the plugin should be installed. You can see what value to use for this option with *Note `SHOW VARIABLES': show-variables.: mysql> SHOW VARIABLES LIKE 'basedir'; +---------------+------------------+ | Variable_name | Value | +---------------+------------------+ | base | /usr/local/mysql | +---------------+------------------+ The location of the plugin directory where you should install the library is given by the `plugin_dir' system variable. For example: mysql> SHOW VARIABLES LIKE 'plugin_dir'; +---------------+-----------------------------------+ | Variable_name | Value | +---------------+-----------------------------------+ | plugin_dir | /usr/local/mysql/lib/mysql/plugin | +---------------+-----------------------------------+ To install the plugin library, use `make': shell> make install Verify that `make install' installed the plugin library in the proper directory. After installing it, make sure that the library permissions permit it to be executed by the server.  File: manual.info, Node: writing-full-text-plugins, Next: writing-daemon-plugins, Prev: compiling-plugin-libraries, Up: writing-plugins 22.2.4.6 Writing Full-Text Parser Plugins ......................................... A full-text parser server plugin can be used to replace or modify the built-in full-text parser. This section describes how to write a full-text parser plugin named `simple_parser'. This plugin performs parsing based on simpler rules than those used by the MySQL built-in full-text parser: Words are nonempty runs of whitespace characters. The instructions use the source code in the `plugin/fulltext' directory of MySQL source distributions, so change location into that directory. The following procedure describes how the plugin library is created: 1. To write a full-text parser plugin, include the following header file in the plugin source file. Other MySQL or general header files might also be needed. #include `plugin.h' defines the `MYSQL_FTPARSER_PLUGIN' server plugin type and the data structures needed to declare the plugin. 2. Set up the library descriptor for the plugin library file. This descriptor contains the general plugin descriptor for the server plugin. For a full-text parser plugin, the type must be `MYSQL_FTPARSER_PLUGIN'. This is the value that identifies the plugin as being legal for use in a `WITH PARSER' clause when creating a `FULLTEXT' index. (No other plugin type is legal for this clause.) For example, the library descriptor for a library that contains a single full-text parser plugin named `simple_parser' looks like this: mysql_declare_plugin(ftexample) { MYSQL_FTPARSER_PLUGIN, /* type */ &simple_parser_descriptor, /* descriptor */ "simple_parser", /* name */ "Oracle Corporation", /* author */ "Simple Full-Text Parser", /* description */ PLUGIN_LICENSE_GPL, /* plugin license */ simple_parser_plugin_init, /* init function (when loaded) */ simple_parser_plugin_deinit,/* deinit function (when unloaded) */ 0x0001, /* version */ simple_status, /* status variables */ simple_system_variables, /* system variables */ NULL } mysql_declare_plugin_end; The `name' member (`simple_parser') indicates the name to use for references to the plugin in statements such as *Note `INSTALL PLUGIN': install-plugin. or *Note `UNINSTALL PLUGIN': uninstall-plugin. This is also the name displayed by *Note `SHOW PLUGINS': show-plugins. or *Note `INFORMATION_SCHEMA.PLUGINS': plugins-table. For more information, see *Note server-plugin-descriptors::. 3. Set up the type-specific plugin descriptor. Each general plugin descriptor in the library descriptor points to a type-specific descriptor. For a full-text parser plugin, the type-specific descriptor is an instance of the `st_mysql_ftparser' structure in the `plugin.h' file: struct st_mysql_ftparser { int interface_version; int (*parse)(MYSQL_FTPARSER_PARAM *param); int (*init)(MYSQL_FTPARSER_PARAM *param); int (*deinit)(MYSQL_FTPARSER_PARAM *param); }; As shown by the structure definition, the descriptor has an interface version number and contains pointers to three functions. The version is specified using a symbol of the form `MYSQL_XXX_INTERFACE_VERSION' (such as (`MYSQL_FTPARSER_INTERFACE_VERSION' for full-text parser plugins) The `init' and `deinit' members should point to a function or be set to 0 if the function is not needed. The `parse' member must point to the function that performs the parsing. In the `simple_parser' declaration, that descriptor is indicated by `&simple_parser_descriptor'. The descriptor specifies the version number for the full-text plugin interface (as given by `MYSQL_FTPARSER_INTERFACE_VERSION'), and the plugin's parsing, initialization, and deinitialization functions: static struct st_mysql_ftparser simple_parser_descriptor= { MYSQL_FTPARSER_INTERFACE_VERSION, /* interface version */ simple_parser_parse, /* parsing function */ simple_parser_init, /* parser init function */ simple_parser_deinit /* parser deinit function */ }; A full-text parser plugin is used in two different contexts, indexing and searching. In both contexts, the server calls the initialization and deinitialization functions at the beginning and end of processing each SQL statement that causes the plugin to be invoked. However, during statement processing, the server calls the main parsing function in context-specific fashion: * For indexing, the server calls the parser for each column value to be indexed. * For searching, the server calls the parser to parse the search string. The parser might also be called for rows processed by the statement. In natural language mode, there is no need for the server to call the parser. For boolean mode phrase searches or natural language searches with query expansion, the parser is used to parse column values for information that is not in the index. Also, if a boolean mode search is done for a column that has no `FULLTEXT' index, the built-in parser will be called. (Plugins are associated with specific indexes. If there is no index, no plugin is used.) The plugin declaration in the general plugin descriptor has `init' and `deinit' members that point initialization and deinitialization functions, and so does the type-specific plugin descriptor to which it points. However, these pairs of functions have different purposes and are invoked for different reasons: * For the plugin declaration in the general plugin descriptor, the initialization and deinitialization functions are invoked when the plugin is loaded and unloaded. * For the type-specific plugin descriptor, the initialization and deinitialization functions are invoked per SQL statement for which the plugin is used. Each interface function named in the plugin descriptor should return zero for success or nonzero for failure, and each of them receives an argument that points to a `MYSQL_FTPARSER_PARAM' structure containing the parsing context. The structure has this definition: typedef struct st_mysql_ftparser_param { int (*mysql_parse)(struct st_mysql_ftparser_param *, char *doc, int doc_len); int (*mysql_add_word)(struct st_mysql_ftparser_param *, char *word, int word_len, MYSQL_FTPARSER_BOOLEAN_INFO *boolean_info); void *ftparser_state; void *mysql_ftparam; struct charset_info_st *cs; char *doc; int length; int flags; enum enum_ftparser_mode mode; } MYSQL_FTPARSER_PARAM; *Note*: The definition shown is current as of MySQL 5.1.12. It is incompatible with versions of MySQL 5.1 older than 5.1.12. The structure members are used as follows: * `mysql_parse': A pointer to a callback function that invokes the server's built-in parser. Use this callback when the plugin acts as a front end to the built-in parser. That is, when the plugin parsing function is called, it should process the input to extract the text and pass the text to the `mysql_parse' callback. The first parameter for this callback function should be the `param' value itself: param->mysql_parse(param, ...); A front end plugin can extract text and pass it all at once to the built-in parser, or it can extract and pass text to the built-in parser a piece at a time. However, in this case, the built-in parser treats the pieces of text as though there are implicit word breaks between them. * `mysql_add_word': A pointer to a callback function that adds a word to a full-text index or to the list of search terms. Use this callback when the parser plugin replaces the built-in parser. That is, when the plugin parsing function is called, it should parse the input into words and invoke the `mysql_add_word' callback for each word. The first parameter for this callback function should be the `param' value itself: param->mysql_add_word(param, ...); * `ftparser_state': This is a generic pointer. The plugin can set it to point to information to be used internally for its own purposes. * `mysql_ftparam': This is set by the server. It is passed as the first argument to the `mysql_parse' or `mysql_add_word' callback. * `cs': A pointer to information about the character set of the text, or 0 if no information is available. * `doc': A pointer to the text to be parsed. * `length': The length of the text to be parsed, in bytes. * `flags': Parser flags. This is zero if there are no special flags. Currently, the only nonzero flag is `MYSQL_FTFLAGS_NEED_COPY', which means that `mysql_add_word()' must save a copy of the word (that is, it cannot use a pointer to the word because the word is in a buffer that will be overwritten.) This member was added in MySQL 5.1.12. This flag might be set or reset by MySQL before calling the parser plugin, by the parser plugin itself, or by the `mysql_parse()' function. * `mode': The parsing mode. This value will be one of the following constants: * `MYSQL_FTPARSER_SIMPLE_MODE': Parse in fast and simple mode, which is used for indexing and for natural language queries. The parser should pass to the server only those words that should be indexed. If the parser uses length limits or a stopword list to determine which words to ignore, it should not pass such words to the server. * `MYSQL_FTPARSER_WITH_STOPWORDS': Parse in stopword mode. This is used in boolean searches for phrase matching. The parser should pass all words to the server, even stopwords or words that are outside any normal length limits. * `MYSQL_FTPARSER_FULL_BOOLEAN_INFO': Parse in boolean mode. This is used for parsing boolean query strings. The parser should recognize not only words but also boolean-mode operators and pass them to the server as tokens using the `mysql_add_word' callback. To tell the server what kind of token is being passed, the plugin needs to fill in a `MYSQL_FTPARSER_BOOLEAN_INFO' structure and pass a pointer to it. If the parser is called in boolean mode, the `param->mode' value will be `MYSQL_FTPARSER_FULL_BOOLEAN_INFO'. The `MYSQL_FTPARSER_BOOLEAN_INFO' structure that the parser uses for passing token information to the server looks like this: typedef struct st_mysql_ftparser_boolean_info { enum enum_ft_token_type type; int yesno; int weight_adjust; bool wasign; bool trunc; /* These are parser state and must be removed. */ byte prev; byte *quot; } MYSQL_FTPARSER_BOOLEAN_INFO; The parser should fill in the structure members as follows: * `type': The token type. The following table shows the permissible types. *Full-Text Parser Token Types* Token Value Meaning `FT_TOKEN_EOF' End of data `FT_TOKEN_WORD' A regular word `FT_TOKEN_LEFT_PAREN' The beginning of a group or subexpression `FT_TOKEN_RIGHT_PAREN' The end of a group or subexpression `FT_TOKEN_STOPWORD' A stopword * `yesno': Whether the word must be present for a match to occur. 0 means that the word is optional but increases the match relevance if it is present. Values larger than 0 mean that the word must be present. Values smaller than 0 mean that the word must not be present. * `weight_adjust': A weighting factor that determines how much a match for the word counts. It can be used to increase or decrease the word's importance in relevance calculations. A value of zero indicates no weight adjustment. Values greater than or less than zero mean higher or lower weight, respectively. The examples at *Note fulltext-boolean::, that use the `<' and `>' operators illustrate how weighting works. * `wasign': The sign of the weighting factor. A negative value acts like the `~' boolean-search operator, which causes the word's contribution to the relevance to be negative. * `trunc': Whether matching should be done as if the boolean-mode `*' truncation operator had been given. Plugins should not use the `prev' and `quot' members of the `MYSQL_FTPARSER_BOOLEAN_INFO' structure. 4. Set up the plugin interface functions. The general plugin descriptor in the library descriptor names the initialization and deinitialization functions that the server should invoke when it loads and unloads the plugin. For `simple_parser', these functions do nothing but return zero to indicate that they succeeded: static int simple_parser_plugin_init(void *arg __attribute__((unused))) { return(0); } static int simple_parser_plugin_deinit(void *arg __attribute__((unused))) { return(0); } Because those functions do not actually do anything, you could omit them and specify 0 for each of them in the plugin declaration. The type-specific plugin descriptor for `simple_parser' names the initialization, deinitialization, and parsing functions that the server invokes when the plugin is used. For `simple_parser', the initialization and deinitialization functions do nothing: static int simple_parser_init(MYSQL_FTPARSER_PARAM *param __attribute__((unused))) { return(0); } static int simple_parser_deinit(MYSQL_FTPARSER_PARAM *param __attribute__((unused))) { return(0); } Here too, because those functions do nothing, you could omit them and specify 0 for each of them in the plugin descriptor. The main parsing function, `simple_parser_parse()', acts as a replacement for the built-in full-text parser, so it needs to split text into words and pass each word to the server. The parsing function's first argument is a pointer to a structure that contains the parsing context. This structure has a `doc' member that points to the text to be parsed, and a `length' member that indicates how long the text is. The simple parsing done by the plugin considers nonempty runs of whitespace characters to be words, so it identifies words like this: static int simple_parser_parse(MYSQL_FTPARSER_PARAM *param) { char *end, *start, *docend= param->doc + param->length; for (end= start= param->doc;; end++) { if (end == docend) { if (end > start) add_word(param, start, end - start); break; } else if (isspace(*end)) { if (end > start) add_word(param, start, end - start); start= end + 1; } } return(0); } As the parser finds each word, it invokes a function `add_word()' to pass the word to the server. `add_word()' is a helper function only; it is not part of the plugin interface. The parser passes the parsing context pointer to `add_word()', as well as a pointer to the word and a length value: static void add_word(MYSQL_FTPARSER_PARAM *param, char *word, size_t len) { MYSQL_FTPARSER_BOOLEAN_INFO bool_info= { FT_TOKEN_WORD, 0, 0, 0, 0, ' ', 0 }; param->mysql_add_word(param, word, len, &bool_info); } For boolean-mode parsing, `add_word()' fills in the members of the `bool_info' structure as described earlier in the discussion of the `st_mysql_ftparser_boolean_info' structure. 5. Set up the status variables. For the `simple_parser' plugin, the following status variable array sets up one status variable with a value that is static text, and another with a value that is stored in a long integer variable: long number_of_calls= 0; struct st_mysql_show_var simple_status[]= { {"static", (char *)"just a static text", SHOW_CHAR}, {"called", (char *)&number_of_calls, SHOW_LONG}, {0,0,0} }; When the plugin is installed, the plugin name and the `name' value are joined with an underscore to form the name displayed by *Note `SHOW STATUS': show-status. For the array just shown, the resulting status variable names are `simple_parser_static' and `simple_parser_called'. This convention means that you can easily display the variables for a plugin using its name: mysql> SHOW STATUS LIKE 'simple_parser%'; +----------------------+--------------------+ | Variable_name | Value | +----------------------+--------------------+ | simple_parser_static | just a static text | | simple_parser_called | 0 | +----------------------+--------------------+ 6. To compile and install a plugin library object file, use the instructions in *Note compiling-plugin-libraries::. For the `simple_parser' plugin, it is compiled and installed when you build MySQL from source. It is also included in binary distributions. The build process produces a shared object library with a name of `mypluglib.so' (the extension might be different depending on your platform). To use the library file, it must be installed in the plugin directory (the directory named by the `plugin_dir' system variable). 7. To use the plugin, register it with the server. For example, to register the plugin at runtime, use this statement (change the extension as necessary): mysql> INSTALL PLUGIN simple_parser SONAME 'mypluglib.so'; For additional information about plugin loading, see *Note server-plugin-loading::. 8. To verify plugin installation, examine the *Note `INFORMATION_SCHEMA.PLUGINS': plugins-table. table or use the *Note `SHOW PLUGINS': show-plugins. statement. 9. Test the plugin to verify that it works properly. Create a table that contains a string column and associate the parser plugin with a `FULLTEXT' index on the column: mysql> CREATE TABLE t (c VARCHAR(255), -> FULLTEXT (c) WITH PARSER simple_parser -> ) ENGINE=MyISAM; Query OK, 0 rows affected (0.01 sec) Insert some text into the table and try some searches. These should verify that the parser plugin treats all nonwhitespace characters as word characters: mysql> INSERT INTO t VALUES -> ('latin1_general_cs is a case-sensitive collation'), -> ('I\'d like a case of oranges'), -> ('this is sensitive information'), -> ('another row'), -> ('yet another row'); Query OK, 5 rows affected (0.02 sec) Records: 5 Duplicates: 0 Warnings: 0 mysql> SELECT c FROM t; +-------------------------------------------------+ | c | +-------------------------------------------------+ | latin1_general_cs is a case-sensitive collation | | I'd like a case of oranges | | this is sensitive information | | another row | | yet another row | +-------------------------------------------------+ 5 rows in set (0.00 sec) mysql> SELECT MATCH(c) AGAINST('case') FROM t; +--------------------------+ | MATCH(c) AGAINST('case') | +--------------------------+ | 0 | | 1.2968142032623 | | 0 | | 0 | | 0 | +--------------------------+ 5 rows in set (0.00 sec) mysql> SELECT MATCH(c) AGAINST('sensitive') FROM t; +-------------------------------+ | MATCH(c) AGAINST('sensitive') | +-------------------------------+ | 0 | | 0 | | 1.3253291845322 | | 0 | | 0 | +-------------------------------+ 5 rows in set (0.01 sec) mysql> SELECT MATCH(c) AGAINST('case-sensitive') FROM t; +------------------------------------+ | MATCH(c) AGAINST('case-sensitive') | +------------------------------------+ | 1.3109166622162 | | 0 | | 0 | | 0 | | 0 | +------------------------------------+ 5 rows in set (0.01 sec) mysql> SELECT MATCH(c) AGAINST('I\'d') FROM t; +--------------------------+ | MATCH(c) AGAINST('I\'d') | +--------------------------+ | 0 | | 1.2968142032623 | | 0 | | 0 | | 0 | +--------------------------+ 5 rows in set (0.01 sec) Note how neither `case' nor `insensitive' match `case-insensitive' the way that they would for the built-in parser.  File: manual.info, Node: writing-daemon-plugins, Prev: writing-full-text-plugins, Up: writing-plugins 22.2.4.7 Writing Daemon Plugins ............................... A daemon plugin is a simple type of plugin used for code that should be run by the server but that does not communicate with it. This section describes how to write a daemon server plugin, using the example plugin found in the `plugin/daemon_example' directory of MySQL source distributions. That directory contains the `daemon_example.cc' source file for a daemon plugin named `daemon_example' that writes a heartbeat string at regular intervals to a file named `mysql-heartbeat.log' in the data directory. To write a daemon plugin, include the following header file in the plugin source file. Other MySQL or general header files might also be needed. #include `plugin.h' defines the `MYSQL_DAEMON_PLUGIN' server plugin type and the data structures needed to declare the plugin. The `daemon_example.cc' file sets up the library descriptor as follows. The library descriptor includes a single general server plugin descriptor. mysql_declare_plugin(daemon_example) { MYSQL_DAEMON_PLUGIN, &daemon_example_plugin, "daemon_example", "Brian Aker", "Daemon example, creates a heartbeat beat file in mysql-heartbeat.log", PLUGIN_LICENSE_GPL, daemon_example_plugin_init, /* Plugin Init */ daemon_example_plugin_deinit, /* Plugin Deinit */ 0x0100 /* 1.0 */, NULL, /* status variables */ NULL, /* system variables */ NULL /* config options */ } mysql_declare_plugin_end; The `name' member (`daemon_example') indicates the name to use for references to the plugin in statements such as *Note `INSTALL PLUGIN': install-plugin. or *Note `UNINSTALL PLUGIN': uninstall-plugin. This is also the name displayed by *Note `SHOW PLUGINS': show-plugins. or *Note `INFORMATION_SCHEMA.PLUGINS': plugins-table. The second member of the plugin descriptor, `daemon_example_plugin', points to the type-specific daemon plugin descriptor. This structure consists only of the type-specific API version number: struct st_mysql_daemon daemon_example_plugin= { MYSQL_DAEMON_INTERFACE_VERSION }; The type-specific structure has no interface functions. There is no communication between the server and the plugin, except that the server calls the initialization and deinitialization functions from the general plugin descriptor to start and stop the plugin: * `daemon_example_plugin_init()' opens the heartbeat file and spawns a thread that wakes up periodically and writes the next message to the file. * `daemon_example_plugin_deinit()' closes the file and performs other cleanup. To compile and install a plugin library object file, use the instructions in *Note compiling-plugin-libraries::. For the `daemon_example' plugin, it is compiled and installed when you build MySQL from source. It is also included in binary distributions. The build process produces a shared object library with a name of `libdaemon_example.so' (the extension might be different depending on your platform). To use the library file, it must be installed in the plugin directory (the directory named by the `plugin_dir' system variable). To use the plugin, register it with the server. For example, to register the plugin at runtime, use this statement (change the extension as necessary): mysql> INSTALL PLUGIN daemon_example SONAME 'libdaemon_example.so'; For additional information about plugin loading, see *Note server-plugin-loading::. To verify plugin installation, examine the *Note `INFORMATION_SCHEMA.PLUGINS': plugins-table. table or use the *Note `SHOW PLUGINS': show-plugins. statement. While the plugin is loaded, it writes a heartbeat string at regular intervals to a file named `mysql-heartbeat.log' in the data directory. This file grows without limit, so after you have satistifed yourself that the plugin operates correctly, unload it: mysql> UNINSTALL PLUGIN daemon_example;  File: manual.info, Node: adding-functions, Next: adding-procedures, Prev: plugin-api, Up: extending-mysql 22.3 Adding New Functions to MySQL ================================== * Menu: * udf-features:: Features of the User-Defined Function Interface * adding-udf:: Adding a New User-Defined Function * adding-native-function:: Adding a New Native Function There are three ways to add new functions to MySQL: * You can add functions through the user-defined function (UDF) interface. User-defined functions are compiled as object files and then added to and removed from the server dynamically using the *Note `CREATE FUNCTION': create-function. and *Note `DROP FUNCTION': drop-function. statements. See *Note create-function-udf::. * You can add functions as native (built-in) MySQL functions. Native functions are compiled into the *Note `mysqld': mysqld. server and become available on a permanent basis. * Another way to add functions is by creating stored functions. These are written using SQL statements rather than by compiling object code. The syntax for writing stored functions is not covered here. See *Note stored-routines::. Each method of creating compiled functions has advantages and disadvantages: * If you write user-defined functions, you must install object files in addition to the server itself. If you compile your function into the server, you don't need to do that. * Native functions require you to modify a source distribution. UDFs do not. You can add UDFs to a binary MySQL distribution. No access to MySQL source is necessary. * If you upgrade your MySQL distribution, you can continue to use your previously installed UDFs, unless you upgrade to a newer version for which the UDF interface changes. For native functions, you must repeat your modifications each time you upgrade. Whichever method you use to add new functions, they can be invoked in SQL statements just like native functions such as `ABS()' or `SOUNDEX()'. See *Note function-resolution::, for the rules describing how the server interprets references to different kinds of functions. The following sections describe features of the UDF interface, provide instructions for writing UDFs, discuss security precautions that MySQL takes to prevent UDF misuse, and describe how to add native MySQL functions. For example source code that illustrates how to write UDFs, take a look at the `sql/udf_example.c' file that is provided in MySQL source distributions.  File: manual.info, Node: udf-features, Next: adding-udf, Prev: adding-functions, Up: adding-functions 22.3.1 Features of the User-Defined Function Interface ------------------------------------------------------ The MySQL interface for user-defined functions provides the following features and capabilities: * Functions can return string, integer, or real values and can accept arguments of those same types. * You can define simple functions that operate on a single row at a time, or aggregate functions that operate on groups of rows. * Information is provided to functions that enables them to check the number, types, and names of the arguments passed to them. * You can tell MySQL to coerce arguments to a given type before passing them to a function. * You can indicate that a function returns `NULL' or that an error occurred.  File: manual.info, Node: adding-udf, Next: adding-native-function, Prev: udf-features, Up: adding-functions 22.3.2 Adding a New User-Defined Function ----------------------------------------- * Menu: * udf-calling:: UDF Calling Sequences for Simple Functions * udf-aggr-calling:: UDF Calling Sequences for Aggregate Functions * udf-arguments:: UDF Argument Processing * udf-return-values:: UDF Return Values and Error Handling * udf-compiling:: Compiling and Installing User-Defined Functions * udf-security:: User-Defined Function Security Precautions For the UDF mechanism to work, functions must be written in C or C++ and your operating system must support dynamic loading. MySQL source distributions include a file `sql/udf_example.c' that defines 5 new functions. Consult this file to see how UDF calling conventions work. The `include/mysql_com.h' header file defines UDF-related symbols and data structures. (You need not include this header file directly because it is included by `mysql.h'.) A UDF contains code that becomes part of the running server, so when you write a UDF, you are bound by any and all constraints that otherwise apply to writing server code. For example, you may have problems if you attempt to use functions from the `libstdc++' library. These constraints may change in future versions of the server, so it is possible that server upgrades will require revisions to UDFs that were originally written for older servers. For information about these constraints, see *Note source-configuration-options::, and *Note compilation-problems::. To be able to use UDFs, you need to link *Note `mysqld': mysqld. dynamically. Don't configure MySQL using `--with-mysqld-ldflags=-all-static'. If you want to use a UDF that needs to access symbols from *Note `mysqld': mysqld. (for example, the `metaphone' function in `sql/udf_example.c' that uses `default_charset_info'), you must link the program with `-rdynamic' (see `man dlopen'). If you plan to use UDFs, the rule of thumb is to configure MySQL with `--with-mysqld-ldflags=-rdynamic' unless you have a very good reason not to. For each function that you want to use in SQL statements, you should define corresponding C (or C++) functions. In the following discussion, the name `xxx' is used for an example function name. To distinguish between SQL and C/C++ usage, `XXX()' (uppercase) indicates an SQL function call, and `xxx()' (lowercase) indicates a C/C++ function call. *Note*: When using C++ you can encapsulate your C functions within: extern "C" { ... } This will ensure that your C++ function names remain readable in the completed UDF. The C/C++ functions that you write to implement the interface for `XXX()' are: * `xxx()' (required) The main function. This is where the function result is computed. The correspondence between the SQL function data type and the return type of your C/C++ function is shown here. SQL Type C/C++ Type `STRING' `char *' *Note `INTEGER': `long long' numeric-types. *Note `REAL': `double' numeric-types. It is also possible to declare a *Note `DECIMAL': numeric-types. function, but currently the value is returned as a string, so you should write the UDF as though it were a `STRING' function. `ROW' functions are not implemented. * `xxx_init()' (optional) The initialization function for `xxx()'. It can be used for the following purposes: * To check the number of arguments to `XXX()'. * To check that the arguments are of a required type or, alternatively, to tell MySQL to coerce arguments to the types you want when the main function is called. * To allocate any memory required by the main function. * To specify the maximum length of the result. * To specify (for *Note `REAL': numeric-types. functions) the maximum number of decimal places in the result. * To specify whether the result can be `NULL'. * `xxx_deinit()' (optional) The deinitialization function for `xxx()'. It should deallocate any memory allocated by the initialization function. When an SQL statement invokes `XXX()', MySQL calls the initialization function `xxx_init()' to let it perform any required setup, such as argument checking or memory allocation. If `xxx_init()' returns an error, MySQL aborts the SQL statement with an error message and does not call the main or deinitialization functions. Otherwise, MySQL calls the main function `xxx()' once for each row. After all rows have been processed, MySQL calls the deinitialization function `xxx_deinit()' so that it can perform any required cleanup. For aggregate functions that work like `SUM()', you must also provide the following functions: * `xxx_clear()' Reset the current aggregate value but do not insert the argument as the initial aggregate value for a new group. * `xxx_add()' Add the argument to the current aggregate value. MySQL handles aggregate UDFs as follows: 1. Call `xxx_init()' to let the aggregate function allocate any memory it needs for storing results. 2. Sort the table according to the `GROUP BY' expression. 3. Call `xxx_clear()' for the first row in each new group. 4. Call `xxx_add()' for each row that belongs in the same group. 5. Call `xxx()' to get the result for the aggregate when the group changes or after the last row has been processed. 6. Repeat steps 3 to 5 until all rows has been processed 7. Call `xxx_deinit()' to let the UDF free any memory it has allocated. All functions must be thread-safe. This includes not just the main function, but the initialization and deinitialization functions as well, and also the additional functions required by aggregate functions. A consequence of this requirement is that you are not permitted to allocate any global or static variables that change! If you need memory, you should allocate it in `xxx_init()' and free it in `xxx_deinit()'.  File: manual.info, Node: udf-calling, Next: udf-aggr-calling, Prev: adding-udf, Up: adding-udf 22.3.2.1 UDF Calling Sequences for Simple Functions ................................................... This section describes the different functions that you need to define when you create a simple UDF. *Note adding-udf::, describes the order in which MySQL calls these functions. The main `xxx()' function should be declared as shown in this section. Note that the return type and parameters differ, depending on whether you declare the SQL function `XXX()' to return `STRING', *Note `INTEGER': numeric-types, or *Note `REAL': numeric-types. in the *Note `CREATE FUNCTION': create-function. statement: For `STRING' functions: char *xxx(UDF_INIT *initid, UDF_ARGS *args, char *result, unsigned long *length, char *is_null, char *error); For *Note `INTEGER': numeric-types. functions: long long xxx(UDF_INIT *initid, UDF_ARGS *args, char *is_null, char *error); For *Note `REAL': numeric-types. functions: double xxx(UDF_INIT *initid, UDF_ARGS *args, char *is_null, char *error); *Note `DECIMAL': numeric-types. functions return string values and should be declared the same way as `STRING' functions. `ROW' functions are not implemented. The initialization and deinitialization functions are declared like this: my_bool xxx_init(UDF_INIT *initid, UDF_ARGS *args, char *message); void xxx_deinit(UDF_INIT *initid); The `initid' parameter is passed to all three functions. It points to a `UDF_INIT' structure that is used to communicate information between functions. The `UDF_INIT' structure members follow. The initialization function should fill in any members that it wishes to change. (To use the default for a member, leave it unchanged.) * `my_bool maybe_null' `xxx_init()' should set `maybe_null' to `1' if `xxx()' can return `NULL'. The default value is `1' if any of the arguments are declared `maybe_null'. * `unsigned int decimals' The number of decimal digits to the right of the decimal point. The default value is the maximum number of decimal digits in the arguments passed to the main function. For example, if the function is passed `1.34', `1.345', and `1.3', the default would be 3, because `1.345' has 3 decimal digits. For arguments that have no fixed number of decimals, the `decimals' value is set to 31, which is 1 more than the maximum number of decimals permitted for the *Note `DECIMAL': numeric-types, *Note `FLOAT': numeric-types, and *Note `DOUBLE': numeric-types. data types. A `decimals' value of 31 is used for arguments in cases such as a *Note `FLOAT': numeric-types. or *Note `DOUBLE': numeric-types. column declared without an explicit number of decimals (for example, *Note `FLOAT': numeric-types. rather than `FLOAT(10,3)') and for floating-point constants such as `1345E-3'. It is also used for string and other nonnumber arguments that might be converted within the function to numeric form. The value to which the `decimals' member is initialized is only a default. It can be changed within the function to reflect the actual calculation performed. The default is determined such that the largest number of decimals of the arguments is used. If the number of decimals is 31 for even one of the arguments, that is the value used for `decimals'. * `unsigned int max_length' The maximum length of the result. The default `max_length' value differs depending on the result type of the function. For string functions, the default is the length of the longest argument. For integer functions, the default is 21 digits. For real functions, the default is 13 plus the number of decimal digits indicated by `initid->decimals'. (For numeric functions, the length includes any sign or decimal point characters.) If you want to return a blob value, you can set `max_length' to 65KB or 16MB. This memory is not allocated, but the value is used to decide which data type to use if there is a need to temporarily store the data. * `char *ptr' A pointer that the function can use for its own purposes. For example, functions can use `initid->ptr' to communicate allocated memory among themselves. `xxx_init()' should allocate the memory and assign it to this pointer: initid->ptr = allocated_memory; In `xxx()' and `xxx_deinit()', refer to `initid->ptr' to use or deallocate the memory. * `my_bool const_item' `xxx_init()' should set `const_item' to `1' if `xxx()' always returns the same value and to `0' otherwise.  File: manual.info, Node: udf-aggr-calling, Next: udf-arguments, Prev: udf-calling, Up: adding-udf 22.3.2.2 UDF Calling Sequences for Aggregate Functions ...................................................... This section describes the different functions that you need to define when you create an aggregate UDF. *Note adding-udf::, describes the order in which MySQL calls these functions. * `xxx_reset()' This function is called when MySQL finds the first row in a new group. It should reset any internal summary variables and then use the given `UDF_ARGS' argument as the first value in your internal summary value for the group. Declare `xxx_reset()' as follows: void xxx_reset(UDF_INIT *initid, UDF_ARGS *args, char *is_null, char *error); `xxx_reset()' is not needed or used in MySQL 5.1, in which the UDF interface uses `xxx_clear()' instead. However, you can define both `xxx_reset()' and `xxx_clear()' if you want to have your UDF work with older versions of the server. (If you do include both functions, the `xxx_reset()' function in many cases can be implemented internally by calling `xxx_clear()' to reset all variables, and then calling `xxx_add()' to add the `UDF_ARGS' argument as the first value in the group.) * `xxx_clear()' This function is called when MySQL needs to reset the summary results. It is called at the beginning for each new group but can also be called to reset the values for a query where there were no matching rows. Declare `xxx_clear()' as follows: void xxx_clear(UDF_INIT *initid, char *is_null, char *error); `is_null' is set to point to `CHAR(0)' before calling `xxx_clear()'. If something went wrong, you can store a value in the variable to which the `error' argument points. `error' points to a single-byte variable, not to a string buffer. `xxx_clear()' is required by MySQL 5.1. * `xxx_add()' This function is called for all rows that belong to the same group. You should use it to add the value in the `UDF_ARGS' argument to your internal summary variable. void xxx_add(UDF_INIT *initid, UDF_ARGS *args, char *is_null, char *error); The `xxx()' function for an aggregate UDF should be declared the same way as for a nonaggregate UDF. See *Note udf-calling::. For an aggregate UDF, MySQL calls the `xxx()' function after all rows in the group have been processed. You should normally never access its `UDF_ARGS' argument here but instead return a value based on your internal summary variables. Return value handling in `xxx()' should be done the same way as for a nonaggregate UDF. See *Note udf-return-values::. The `xxx_reset()' and `xxx_add()' functions handle their `UDF_ARGS' argument the same way as functions for nonaggregate UDFs. See *Note udf-arguments::. The pointer arguments to `is_null' and `error' are the same for all calls to `xxx_reset()', `xxx_clear()', `xxx_add()' and `xxx()'. You can use this to remember that you got an error or whether the `xxx()' function should return `NULL'. You should not store a string into `*error'! `error' points to a single-byte variable, not to a string buffer. `*is_null' is reset for each group (before calling `xxx_clear()'). `*error' is never reset. If `*is_null' or `*error' are set when `xxx()' returns, MySQL returns `NULL' as the result for the group function.  File: manual.info, Node: udf-arguments, Next: udf-return-values, Prev: udf-aggr-calling, Up: adding-udf 22.3.2.3 UDF Argument Processing ................................ The `args' parameter points to a `UDF_ARGS' structure that has the members listed here: * `unsigned int arg_count' The number of arguments. Check this value in the initialization function if you require your function to be called with a particular number of arguments. For example: if (args->arg_count != 2) { strcpy(message,"XXX() requires two arguments"); return 1; } For other `UDF_ARGS' member values that are arrays, array references are zero-based. That is, refer to array members using index values from 0 to `args->arg_count' - 1. * `enum Item_result *arg_type' A pointer to an array containing the types for each argument. The possible type values are `STRING_RESULT', `INT_RESULT', `REAL_RESULT', and `DECIMAL_RESULT'. To make sure that arguments are of a given type and return an error if they are not, check the `arg_type' array in the initialization function. For example: if (args->arg_type[0] != STRING_RESULT || args->arg_type[1] != INT_RESULT) { strcpy(message,"XXX() requires a string and an integer"); return 1; } Arguments of type `DECIMAL_RESULT' are passed as strings, so you should handle them the same way as `STRING_RESULT' values. As an alternative to requiring your function's arguments to be of particular types, you can use the initialization function to set the `arg_type' elements to the types you want. This causes MySQL to coerce arguments to those types for each call to `xxx()'. For example, to specify that the first two arguments should be coerced to string and integer, respectively, do this in `xxx_init()': args->arg_type[0] = STRING_RESULT; args->arg_type[1] = INT_RESULT; Exact-value decimal arguments such as `1.3' or *Note `DECIMAL': numeric-types. column values are passed with a type of `DECIMAL_RESULT'. However, the values are passed as strings. If you want to receive a number, use the initialization function to specify that the argument should be coerced to a `REAL_RESULT' value: args->arg_type[2] = REAL_RESULT; * `char **args' `args->args' communicates information to the initialization function about the general nature of the arguments passed to your function. For a constant argument `i', `args->args[i]' points to the argument value. (See later for instructions on how to access the value properly.) For a nonconstant argument, `args->args[i]' is `0'. A constant argument is an expression that uses only constants, such as `3' or `4*7-2' or `SIN(3.14)'. A nonconstant argument is an expression that refers to values that may change from row to row, such as column names or functions that are called with nonconstant arguments. For each invocation of the main function, `args->args' contains the actual arguments that are passed for the row currently being processed. If argument `i' represents `NULL', `args->args[i]' is a null pointer (0). If the argument is not `NULL', functions can refer to it as follows: * An argument of type `STRING_RESULT' is given as a string pointer plus a length, to enable handling of binary data or data of arbitrary length. The string contents are available as `args->args[i]' and the string length is `args->lengths[i]'. Do not assume that the string is null-terminated. * For an argument of type `INT_RESULT', you must cast `args->args[i]' to a `long long' value: long long int_val; int_val = *((long long*) args->args[i]); * For an argument of type `REAL_RESULT', you must cast `args->args[i]' to a `double' value: double real_val; real_val = *((double*) args->args[i]); * For an argument of type `DECIMAL_RESULT', the value is passed as a string and should be handled like a `STRING_RESULT' value. * `ROW_RESULT' arguments are not implemented. * `unsigned long *lengths' For the initialization function, the `lengths' array indicates the maximum string length for each argument. You should not change these. For each invocation of the main function, `lengths' contains the actual lengths of any string arguments that are passed for the row currently being processed. For arguments of types `INT_RESULT' or `REAL_RESULT', `lengths' still contains the maximum length of the argument (as for the initialization function). * `char *maybe_null' For the initialization function, the `maybe_null' array indicates for each argument whether the argument value might be null (0 if no, 1 if yes). * `char **attributes' `args->attributes' communicates information about the names of the UDF arguments. For argument `i', the attribute name is available as a string in `args->attributes[i]' and the attribute length is `args->attribute_lengths[i]'. Do not assume that the string is null-terminated. By default, the name of a UDF argument is the text of the expression used to specify the argument. For UDFs, an argument may also have an optional `[AS] ALIAS_NAME' clause, in which case the argument name is ALIAS_NAME. The `attributes' value for each argument thus depends on whether an alias was given. Suppose that a UDF `my_udf()' is invoked as follows: SELECT my_udf(expr1, expr2 AS alias1, expr3 alias2); In this case, the `attributes' and `attribute_lengths' arrays will have these values: args->attributes[0] = "expr1" args->attribute_lengths[0] = 5 args->attributes[1] = "alias1" args->attribute_lengths[1] = 6 args->attributes[2] = "alias2" args->attribute_lengths[2] = 6 * `unsigned long *attribute_lengths' The `attribute_lengths' array indicates the length of each argument name.  File: manual.info, Node: udf-return-values, Next: udf-compiling, Prev: udf-arguments, Up: adding-udf 22.3.2.4 UDF Return Values and Error Handling ............................................. The initialization function should return `0' if no error occurred and `1' otherwise. If an error occurs, `xxx_init()' should store a null-terminated error message in the `message' parameter. The message is returned to the client. The message buffer is `MYSQL_ERRMSG_SIZE' characters long, but you should try to keep the message to less than 80 characters so that it fits the width of a standard terminal screen. The return value of the main function `xxx()' is the function value, for `long long' and `double' functions. A string function should return a pointer to the result and set `*length' to the length (in bytes) of the return value. For example: memcpy(result, "result string", 13); *length = 13; MySQL passes a buffer to the `xxx()' function using the `result' parameter. This buffer is sufficiently long to hold 255 characters, which can be multi-byte characters. The `xxx()' function can store the result in this buffer if it fits, in which case the return value should be a pointer to the buffer. If the function stores the result in a different buffer, it should return a pointer to that buffer. If your string function does not use the supplied buffer (for example, if it needs to return a string longer than 255 characters), you must allocate the space for your own buffer with `malloc()' in your `xxx_init()' function or your `xxx()' function and free it in your `xxx_deinit()' function. You can store the allocated memory in the `ptr' slot in the `UDF_INIT' structure for reuse by future `xxx()' calls. See *Note udf-calling::. To indicate a return value of `NULL' in the main function, set `*is_null' to `1': *is_null = 1; To indicate an error return in the main function, set `*error' to `1': *error = 1; If `xxx()' sets `*error' to `1' for any row, the function value is `NULL' for the current row and for any subsequent rows processed by the statement in which `XXX()' was invoked. (`xxx()' is not even called for subsequent rows.)  File: manual.info, Node: udf-compiling, Next: udf-security, Prev: udf-return-values, Up: adding-udf 22.3.2.5 Compiling and Installing User-Defined Functions ........................................................ Files implementing UDFs must be compiled and installed on the host where the server runs. This process is described below for the example UDF file `sql/udf_example.c' that is included in MySQL source distributions. If a UDF will be referred to in statements that will be replicated to slave servers, you must ensure that every slave also has the function available. Otherwise, replication will fail on the slaves when they attempt to invoke the function. The immediately following instructions are for Unix. Instructions for Windows are given later in this section. The `udf_example.c' file contains the following functions: * `metaphon()' returns a metaphon string of the string argument. This is something like a soundex string, but it is more tuned for English. * `myfunc_double()' returns the sum of the ASCII values of the characters in its arguments, divided by the sum of the length of its arguments. * `myfunc_int()' returns the sum of the length of its arguments. * `sequence([const int])' returns a sequence starting from the given number or 1 if no number has been given. * `lookup()' returns the IP address for a host name. * `reverse_lookup()' returns the host name for an IP address. The function may be called either with a single string argument of the form `'xxx.xxx.xxx.xxx'' or with four numbers. * `avgcost()' returns an average cost. This is an aggregate function. A dynamically loadable file should be compiled as a sharable object file, using a command something like this: shell> gcc -shared -o udf_example.so udf_example.c If you are using `gcc' with `configure' and `libtool' (which is how MySQL is configured), you should be able to create `udf_example.so' with a simpler command: shell> make udf_example.la After you compile a shared object containing UDFs, you must install it and tell MySQL about it. Compiling a shared object from `udf_example.c' using `gcc' directly produces a file named `udf_example.so'. Compiling the shared object using `make' produces a file named something like `udf_example.so.0.0.0' in the `.libs' directory (the exact name may vary from platform to platform). Copy the shared object to the server's plugin directory and name it `udf_example.so'. This directory is given by the value of the `plugin_dir' system variable. *Note*: This is a change in MySQL 5.1. For earlier versions of MySQL, the shared object can be located in any directory that is searched by your system's dynamic linker. On some systems, the `ldconfig' program that configures the dynamic linker does not recognize a shared object unless its name begins with `lib'. In this case you should rename a file such as `udf_example.so' to `libudf_example.so'. On Windows, you can compile user-defined functions by using the following procedure: 1. Obtain the development source for MySQL 5.1. See *Note getting-mysql::. 2. Obtain the `CMake' build utility, if necessary, from `http://www.cmake.org'. (Version 2.6 or later is required). 3. In the source tree, look in the `sql' directory. There are files named `udf_example.def' `udf_example.c' there. Copy both files from this directory to your working directory. 4. Create a `CMake' `makefile' (`CMakeLists.txt') with these contents: PROJECT(udf_example) # Path for MySQL include directory INCLUDE_DIRECTORIES("c:/mysql/include") ADD_DEFINITIONS("-DHAVE_DLOPEN") ADD_LIBRARY(udf_example MODULE udf_example.c udf_example.def) TARGET_LINK_LIBRARIES(udf_example wsock32) 5. Create the VC project and solution files: cmake -G "" Invoking `cmake --help' shows you a list of valid Generators. 6. Create `udf_example.dll': devenv udf_example.sln /build Release After the shared object file has been installed, notify *Note `mysqld': mysqld. about the new functions with the following statements. If object files have a suffix different from `.so' on your system, substitute the correct suffix throughout (for example, `.dll' on Windows). mysql> CREATE FUNCTION metaphon RETURNS STRING SONAME 'udf_example.so'; mysql> CREATE FUNCTION myfunc_double RETURNS REAL SONAME 'udf_example.so'; mysql> CREATE FUNCTION myfunc_int RETURNS INTEGER SONAME 'udf_example.so'; mysql> CREATE FUNCTION sequence RETURNS INTEGER SONAME 'udf_example.so'; mysql> CREATE FUNCTION lookup RETURNS STRING SONAME 'udf_example.so'; mysql> CREATE FUNCTION reverse_lookup -> RETURNS STRING SONAME 'udf_example.so'; mysql> CREATE AGGREGATE FUNCTION avgcost -> RETURNS REAL SONAME 'udf_example.so'; To delete functions, use *Note `DROP FUNCTION': drop-function.: mysql> DROP FUNCTION metaphon; mysql> DROP FUNCTION myfunc_double; mysql> DROP FUNCTION myfunc_int; mysql> DROP FUNCTION sequence; mysql> DROP FUNCTION lookup; mysql> DROP FUNCTION reverse_lookup; mysql> DROP FUNCTION avgcost; The *Note `CREATE FUNCTION': create-function. and *Note `DROP FUNCTION': drop-function. statements update the `func' system table in the `mysql' database. The function's name, type and shared library name are saved in the table. You must have the `INSERT' or `DELETE' privilege for the `mysql' database to create or drop functions, respectively. You should not use *Note `CREATE FUNCTION': create-function. to add a function that has previously been created. If you need to reinstall a function, you should remove it with *Note `DROP FUNCTION': drop-function. and then reinstall it with *Note `CREATE FUNCTION': create-function. You would need to do this, for example, if you recompile a new version of your function, so that *Note `mysqld': mysqld. gets the new version. Otherwise, the server continues to use the old version. An active function is one that has been loaded with *Note `CREATE FUNCTION': create-function. and not removed with *Note `DROP FUNCTION': drop-function. All active functions are reloaded each time the server starts, unless you start *Note `mysqld': mysqld. with the `--skip-grant-tables' option. In this case, UDF initialization is skipped and UDFs are unavailable.  File: manual.info, Node: udf-security, Prev: udf-compiling, Up: adding-udf 22.3.2.6 User-Defined Function Security Precautions ................................................... MySQL takes the following measures to prevent misuse of user-defined functions. You must have the `INSERT' privilege to be able to use *Note `CREATE FUNCTION': create-function. and the `DELETE' privilege to be able to use *Note `DROP FUNCTION': drop-function. This is necessary because these statements add and delete rows from the `mysql.func' table. UDFs should have at least one symbol defined in addition to the `xxx' symbol that corresponds to the main `xxx()' function. These auxiliary symbols correspond to the `xxx_init()', `xxx_deinit()', `xxx_reset()', `xxx_clear()', and `xxx_add()' functions. *Note `mysqld': mysqld. also supports an `--allow-suspicious-udfs' option that controls whether UDFs that have only an `xxx' symbol can be loaded. By default, the option is off, to prevent attempts at loading functions from shared object files other than those containing legitimate UDFs. If you have older UDFs that contain only the `xxx' symbol and that cannot be recompiled to include an auxiliary symbol, it may be necessary to specify the `--allow-suspicious-udfs' option. Otherwise, you should avoid enabling this capability. UDF object files cannot be placed in arbitrary directories. They must be located in the server's plugin directory. This directory is given by the value of the `plugin_dir' system variable. *Note*: This is a change in MySQL 5.1. For earlier versions of MySQL, the shared object can be located in any directory that is searched by your system's dynamic linker.  File: manual.info, Node: adding-native-function, Prev: adding-udf, Up: adding-functions 22.3.3 Adding a New Native Function ----------------------------------- To add a new native MySQL function, use the procedure described here, which requires that you use a source distribution. You cannot add native functions to a binary distribution because it is necessary to modify MySQL source code and compile MySQL from the modified source. If you migrate to another version of MySQL (for example, when a new version is released), you must repeat the procedure with the new version. If the new native function will be referred to in statements that will be replicated to slave servers, you must ensure that every slave server also has the function available. Otherwise, replication will fail on the slaves when they attempt to invoke the function. To add a new native function, follow these steps to modify source files in the `sql' directory. For MySQL 5.1, the first two steps apply only as of 5.1.13. For older versions, see the instructions in the corresponding section of the MySQL 5.0 manual. 1. Create a subclass for the function in `item_create.cc': * If the function takes a fixed number of arguments, create a subclass of `Create_func_arg0', `Create_func_arg1', `Create_func_arg2', or `Create_func_arg3', respectively, depending on whether the function takes zero, one, two, or three arguments. For examples, see the `Create_func_uuid', `Create_func_abs', `Create_func_pow', and `Create_func_lpad' classes. * If the function takes a variable number of arguments, create a subclass of `Create_native_func'. For an example, see `Create_func_concat'. 2. To provide a name by which the function can be referred to in SQL statements, register the name in `item_create.cc' by adding a line to this array: static Native_func_registry func_array[] You can register several names for the same function. For example, see the lines for `"LCASE"' and `"LOWER"', which are aliases for `Create_func_lcase'. 3. In `item_func.h', declare a class inheriting from `Item_num_func' or `Item_str_func', depending on whether your function returns a number or a string. 4. In `item_func.cc', add one of the following declarations, depending on whether you are defining a numeric or string function: double Item_func_newname::val() longlong Item_func_newname::val_int() String *Item_func_newname::Str(String *str) If you inherit your object from any of the standard items (like `Item_num_func'), you probably only have to define one of these functions and let the parent object take care of the other functions. For example, the `Item_str_func' class defines a `val()' function that executes `atof()' on the value returned by `::str()'. 5. If the function is nondeterministic, include the following statement in the item constructor to indicate that function results should not be cached: current_thd->lex->safe_to_cache_query=0; A function is nondeterministic if, given fixed values for its arguments, it can return different results for different invocations. 6. You should probably also define the following object function: void Item_func_newname::fix_length_and_dec() This function should at least calculate `max_length' based on the given arguments. `max_length' is the maximum number of characters the function may return. This function should also set `maybe_null = 0' if the main function can't return a `NULL' value. The function can check whether any of the function arguments can return `NULL' by checking the arguments' `maybe_null' variable. Look at `Item_func_mod::fix_length_and_dec' for a typical example of how to do this. All functions must be thread-safe. In other words, do not use any global or static variables in the functions without protecting them with mutexes. If you want to return `NULL' from `::val()', `::val_int()', or `::str()', you should set `null_value' to 1 and return 0. For `::str()' object functions, there are additional considerations to be aware of: * The `String *str' argument provides a string buffer that may be used to hold the result. (For more information about the `String' type, take a look at the `sql_string.h' file.) * The `::str()' function should return the string that holds the result, or `(char*) 0' if the result is `NULL'. * All current string functions try to avoid allocating any memory unless absolutely necessary!  File: manual.info, Node: adding-procedures, Next: porting, Prev: adding-functions, Up: extending-mysql 22.4 Adding New Procedures to MySQL =================================== * Menu: * procedure-analyse:: `PROCEDURE ANALYSE' * writing-a-procedure:: Writing a Procedure In MySQL, you can define a procedure in C++ that can access and modify the data in a query before it is sent to the client. The modification can be done on a row-by-row or `GROUP BY' level. We have created an example procedure to show you what can be done.  File: manual.info, Node: procedure-analyse, Next: writing-a-procedure, Prev: adding-procedures, Up: adding-procedures 22.4.1 `PROCEDURE ANALYSE' -------------------------- `ANALYSE([MAX_ELEMENTS[,MAX_MEMORY]])' `ANALYSE()' is defined in the `sql/sql_analyse.cc' source file, which serves as an example of how to create a procedure for use with the `PROCEDURE' clause of *Note `SELECT': select. statements. `ANALYSE()' is built in and is available by default; other procedures can be created using the format demonstrated in the source file. `ANALYSE()' examines the result from a query and returns an analysis of the results that suggests optimal data types for each column that may help reduce table sizes. To obtain this analysis, append `PROCEDURE ANALYSE' to the end of a *Note `SELECT': select. statement: SELECT ... FROM ... WHERE ... PROCEDURE ANALYSE([MAX_ELEMENTS,[MAX_MEMORY]]) For example: SELECT col1, col2 FROM table1 PROCEDURE ANALYSE(10, 2000); The results show some statistics for the values returned by the query, and propose an optimal data type for the columns. This can be helpful for checking your existing tables, or after importing new data. You may need to try different settings for the arguments so that `PROCEDURE ANALYSE()' does not suggest the *Note `ENUM': enum. data type when it is not appropriate. The arguments are optional and are used as follows: * MAX_ELEMENTS (default 256) is the maximum number of distinct values that `ANALYSE()' notices per column. This is used by `ANALYSE()' to check whether the optimal data type should be of type *Note `ENUM': enum.; if there are more than MAX_ELEMENTS distinct values, then *Note `ENUM': enum. is not a suggested type. * MAX_MEMORY (default 8192) is the maximum amount of memory that `ANALYSE()' should allocate per column while trying to find all distinct values.  File: manual.info, Node: writing-a-procedure, Prev: procedure-analyse, Up: adding-procedures 22.4.2 Writing a Procedure -------------------------- You can find information about procedures by examining the following source files: * `sql/sql_analyse.cc' * `sql/procedure.h' * `sql/procedure.cc' * `sql/sql_select.cc' See also Writing a Procedure (http://forge.mysql.com/wiki/MySQL_Internals_Procedure) at MySQL Forge.  File: manual.info, Node: porting, Prev: adding-procedures, Up: extending-mysql 22.5 Debugging and Porting MySQL ================================ * Menu: * debugging-server:: Debugging a MySQL Server * debugging-client:: Debugging a MySQL Client * the-dbug-package:: The DBUG Package This appendix helps you port MySQL to other operating systems. Do check the list of currently supported operating systems first. See *Note general-installation-issues::. If you have created a new port of MySQL, please let us know so that we can list it here and on our Web site (http://www.mysql.com/), recommending it to other users. *Note*: If you create a new port of MySQL, you are free to copy and distribute it under the GPL license, but it does not make you a copyright holder of MySQL. A working POSIX thread library is needed for the server. Both the server and the client need a working C++ compiler. We use `gcc' on many platforms. Other compilers that are known to work are Sun Studio, HP-UX `aCC', IBM AIX `xlC_r'), Intel `ecc/icc'. With previous versions on the respective platforms, we also used Irix `cc' and Compaq `cxx'. *Important*: If you are trying to build MySQL 5.1 with `icc' on the IA64 platform, and need support for MySQL Cluster, you should first ensure that you are using `icc' version 9.1.043 or later. (For details, see Bug#21875.) To compile only the client, use `./configure --without-server'. If you want or need to change any `Makefile' or the `configure' script, you also need GNU Automake and Autoconf. See *Note installing-development-tree::. All steps needed to remake everything from the most basic files. /bin/rm */.deps/*.P /bin/rm -f config.cache aclocal autoheader aclocal automake autoconf ./configure --with-debug=full --prefix='your installation directory' # The makefiles generated above need GNU make 3.75 or newer. # (called gmake below) gmake clean all install init-db If you run into problems with a new port, you may have to do some debugging of MySQL! See *Note debugging-server::. *Note*: Before you start debugging *Note `mysqld': mysqld, first get the test programs `mysys/thr_alarm' and `mysys/thr_lock' to work. This ensures that your thread installation has even a remote chance to work!  File: manual.info, Node: debugging-server, Next: debugging-client, Prev: porting, Up: porting 22.5.1 Debugging a MySQL Server ------------------------------- * Menu: * compiling-for-debugging:: Compiling MySQL for Debugging * making-trace-files:: Creating Trace Files * making-windows-dumps:: Using `pdb' to create a Windows crashdump * using-gdb-on-mysqld:: Debugging `mysqld' under `gdb' * using-stack-trace:: Using a Stack Trace * using-log-files:: Using Server Logs to Find Causes of Errors in `mysqld' * reproducible-test-case:: Making a Test Case If You Experience Table Corruption If you are using some functionality that is very new in MySQL, you can try to run *Note `mysqld': mysqld. with the `--skip-new' (which disables all new, potentially unsafe functionality) or with `--safe-mode' which disables a lot of optimization that may cause problems. See *Note crashing::. Binary distributions of MySQL server from Oracle include a specific debug binary, `mysqld-debug'. This is a build including the debugging information and is built in the same way as the debug build format described in *Note compiling-for-debugging::. You should use this build when debugging the MySQL server. If *Note `mysqld': mysqld. doesn't want to start, you should verify that you don't have any `my.cnf' files that interfere with your setup! You can check your `my.cnf' arguments with *Note `mysqld --print-defaults': mysqld. and avoid using them by starting with *Note `mysqld --no-defaults ...': mysqld. If *Note `mysqld': mysqld. starts to eat up CPU or memory or if it `hangs,' you can use *Note `mysqladmin processlist status': mysqladmin. to find out if someone is executing a query that takes a long time. It may be a good idea to run *Note `mysqladmin -i10 processlist status': mysqladmin. in some window if you are experiencing performance problems or problems when new clients can't connect. The command *Note `mysqladmin debug': mysqladmin. dumps some information about locks in use, used memory and query usage to the MySQL log file. This may help solve some problems. This command also provides some useful information even if you haven't compiled MySQL for debugging! If the problem is that some tables are getting slower and slower you should try to optimize the table with *Note `OPTIMIZE TABLE': optimize-table. or *Note `myisamchk': myisamchk. See *Note server-administration::. You should also check the slow queries with *Note `EXPLAIN': explain. You should also read the OS-specific section in this manual for problems that may be unique to your environment. See *Note general-installation-issues::.  File: manual.info, Node: compiling-for-debugging, Next: making-trace-files, Prev: debugging-server, Up: debugging-server 22.5.1.1 Compiling MySQL for Debugging ...................................... If you have some very specific problem, you can always try to debug MySQL. To do this you must configure MySQL with the `--with-debug' or the `--with-debug=full' option. You can check whether MySQL was compiled with debugging by doing: *Note `mysqld --help': mysqld. If the `--debug' flag is listed with the options then you have debugging enabled. *Note `mysqladmin ver': mysqladmin. also lists the *Note `mysqld': mysqld. version as *Note `mysql ... --debug': mysql. in this case. If you are using `gcc', the recommended `configure' line is: CC=gcc CFLAGS="-O2" CXX=gcc CXXFLAGS="-O2 -felide-constructors \ -fno-exceptions -fno-rtti" ./configure --prefix=/usr/local/mysql \ --with-debug --with-extra-charsets=complex This avoids problems with the `libstdc++' library and with C++ exceptions (many compilers have problems with C++ exceptions in threaded code) and compile a MySQL version with support for all character sets. If you suspect a memory overrun error, you can configure MySQL with `--with-debug=full', which installs a memory allocation (`SAFEMALLOC') checker. However, running with `SAFEMALLOC' is quite slow, so if you get performance problems you should start *Note `mysqld': mysqld. with the `--skip-safemalloc' option. This disables the memory overrun checks for each call to `malloc()' and `free()'. If *Note `mysqld': mysqld. stops crashing when you compile it with `--with-debug', you probably have found a compiler bug or a timing bug within MySQL. In this case, you can try to add `-g' to the `CFLAGS' and `CXXFLAGS' variables above and not use `--with-debug'. If *Note `mysqld': mysqld. dies, you can at least attach to it with `gdb' or use `gdb' on the core file to find out what happened. When you configure MySQL for debugging you automatically enable a lot of extra safety check functions that monitor the health of *Note `mysqld': mysqld. If they find something `unexpected,' an entry is written to `stderr', which *Note `mysqld_safe': mysqld-safe. directs to the error log! This also means that if you are having some unexpected problems with MySQL and are using a source distribution, the first thing you should do is to configure MySQL for debugging! (The second thing is to send mail to a MySQL mailing list and ask for help. See *Note mailing-lists::. If you believe that you have found a bug, please use the instructions at *Note bug-reports::. In the Windows MySQL distribution, `mysqld.exe' is by default compiled with support for trace files.  File: manual.info, Node: making-trace-files, Next: making-windows-dumps, Prev: compiling-for-debugging, Up: debugging-server 22.5.1.2 Creating Trace Files ............................. If the *Note `mysqld': mysqld. server doesn't start or if you can cause it to crash quickly, you can try to create a trace file to find the problem. To do this, you must have a *Note `mysqld': mysqld. that has been compiled with debugging support. You can check this by executing `mysqld -V'. If the version number ends with `-debug', it is compiled with support for trace files. (On Windows, the debugging server is named *Note `mysqld-debug': mysqld. rather than *Note `mysqld': mysqld. as of MySQL 4.1.) Start the *Note `mysqld': mysqld. server with a trace log in `/tmp/mysqld.trace' on Unix or `C:\mysqld.trace' on Windows: shell> mysqld --debug On Windows, you should also use the `--standalone' flag to not start *Note `mysqld': mysqld. as a service. In a console window, use this command: C:\> mysqld-debug --debug --standalone After this, you can use the `mysql.exe' command-line tool in a second console window to reproduce the problem. You can stop the *Note `mysqld': mysqld. server with *Note `mysqladmin shutdown': mysqladmin. The trace file can become *very large*! To generate a smaller trace file, you can use debugging options something like this: *Note `mysqld --debug=d,info,error,query,general,where:O,/tmp/mysqld.trace': mysqld. This only prints information with the most interesting tags to the trace file. If you make a bug report about this, please only send the lines from the trace file to the appropriate mailing list where something seems to go wrong! If you can't locate the wrong place, you can ftp the trace file, together with a full bug report, to `ftp://ftp.mysql.com/pub/mysql/upload/' so that a MySQL developer can take a look at it. The trace file is made with the *DBUG* package by Fred Fish. See *Note the-dbug-package::.  File: manual.info, Node: making-windows-dumps, Next: using-gdb-on-mysqld, Prev: making-trace-files, Up: debugging-server 22.5.1.3 Using `pdb' to create a Windows crashdump .................................................. Starting with MySQL 5.1.12 the Program Database files (extension `pdb') are included in the Noinstall distribution of MySQL. These files provide information for debugging your MySQL installation in the event of a problem. The PDB file contains more detailed information about `mysqld' and other tools that enables more detailed trace and dump files to be created. You can use these with Dr Watson, `WinDbg' and Visual Studio to debug *Note `mysqld': mysqld. For more information on PDB files, see Microsoft Knowledge Base Article 121366 (http://support.microsoft.com/kb/121366/). For more information on the debugging options available, see Debugging Tools for Windows (http://www.microsoft.com/whdc/devtools/debugging/default.mspx). Dr Watson is installed with all Windows distributions, but if you have installed Windows development tools, Dr Watson may have been replaced with WinDbg, the debugger included with Visual Studio, or the debugging tools provided with Borland or Delphi. To generate a crash file using Dr Watson, follow these steps: 1. Start Dr Watson by running `drwtsn32.exe' interactively using the `-i' option: C:\> drwtsn32 -i 2. Set the `Log File Path' to the directory where you want to store trace files. 3. Make sure `Dump All Thread Contexts' and `Append To Existing Log File'. 4. Uncheck `Dump Symbol Table', `Visual Notification', `Sound Notification' and `Create Crash Dump File'. 5. Set the `Number of Instructions' to a suitable value to capture enough calls in the stacktrace. A value of at 25 should be enough. Note that the file generated can become very large.  File: manual.info, Node: using-gdb-on-mysqld, Next: using-stack-trace, Prev: making-windows-dumps, Up: debugging-server 22.5.1.4 Debugging `mysqld' under `gdb' ....................................... On most systems you can also start *Note `mysqld': mysqld. from `gdb' to get more information if *Note `mysqld': mysqld. crashes. With some older `gdb' versions on Linux you must use `run --one-thread' if you want to be able to debug *Note `mysqld': mysqld. threads. In this case, you can only have one thread active at a time. It is best to upgrade to `gdb' 5.1 because thread debugging works much better with this version! NPTL threads (the new thread library on Linux) may cause problems while running *Note `mysqld': mysqld. under `gdb'. Some symptoms are: * *Note `mysqld': mysqld. hangs during startup (before it writes `ready for connections'). * *Note `mysqld': mysqld. crashes during a `pthread_mutex_lock()' or `pthread_mutex_unlock()' call. In this case, you should set the following environment variable in the shell before starting `gdb': LD_ASSUME_KERNEL=2.4.1 export LD_ASSUME_KERNEL When running *Note `mysqld': mysqld. under `gdb', you should disable the stack trace with `--skip-stack-trace' to be able to catch segfaults within `gdb'. In MySQL 4.0.14 and above you should use the `--gdb' option to *Note `mysqld': mysqld. This installs an interrupt handler for `SIGINT' (needed to stop *Note `mysqld': mysqld. with `^C' to set breakpoints) and disable stack tracing and core file handling. It is very hard to debug MySQL under `gdb' if you do a lot of new connections the whole time as `gdb' doesn't free the memory for old threads. You can avoid this problem by starting *Note `mysqld': mysqld. with `thread_cache_size' set to a value equal to `max_connections' + 1. In most cases just using `--thread_cache_size=5'' helps a lot! If you want to get a core dump on Linux if *Note `mysqld': mysqld. dies with a SIGSEGV signal, you can start *Note `mysqld': mysqld. with the `--core-file' option. This core file can be used to make a backtrace that may help you find out why *Note `mysqld': mysqld. died: shell> gdb mysqld core gdb> backtrace full gdb> quit See *Note crashing::. If you are using `gdb' 4.17.x or above on Linux, you should install a `.gdb' file, with the following information, in your current directory: set print sevenbit off handle SIGUSR1 nostop noprint handle SIGUSR2 nostop noprint handle SIGWAITING nostop noprint handle SIGLWP nostop noprint handle SIGPIPE nostop handle SIGALRM nostop handle SIGHUP nostop handle SIGTERM nostop noprint If you have problems debugging threads with `gdb', you should download gdb 5.x and try this instead. The new `gdb' version has very improved thread handling! Here is an example how to debug *Note `mysqld': mysqld.: shell> gdb /usr/local/libexec/mysqld gdb> run ... backtrace full # Do this when mysqld crashes Include the preceding output in a bug report, which you can file using the instructions in *Note bug-reports::. If *Note `mysqld': mysqld. hangs, you can try to use some system tools like `strace' or `/usr/proc/bin/pstack' to examine where *Note `mysqld': mysqld. has hung. strace /tmp/log libexec/mysqld If you are using the Perl `DBI' interface, you can turn on debugging information by using the `trace' method or by setting the `DBI_TRACE' environment variable.  File: manual.info, Node: using-stack-trace, Next: using-log-files, Prev: using-gdb-on-mysqld, Up: debugging-server 22.5.1.5 Using a Stack Trace ............................ On some operating systems, the error log contains a stack trace if *Note `mysqld': mysqld. dies unexpectedly. You can use this to find out where (and maybe why) *Note `mysqld': mysqld. died. See *Note error-log::. To get a stack trace, you must not compile *Note `mysqld': mysqld. with the `-fomit-frame-pointer' option to gcc. See *Note compiling-for-debugging::. A stack trace in the error log looks something like this: mysqld got signal 11; Attempting backtrace. You can use the following information to find out where mysqld died. If you see no messages after this, something went terribly wrong... stack_bottom = 0x41fd0110 thread_stack 0x40000 mysqld(my_print_stacktrace+0x32)[0x9da402] mysqld(handle_segfault+0x28a)[0x6648e9] /lib/libpthread.so.0[0x7f1a5af000f0] /lib/libc.so.6(strcmp+0x2)[0x7f1a5a10f0f2] mysqld(_Z21check_change_passwordP3THDPKcS2_Pcj+0x7c)[0x7412cb] mysqld(_ZN16set_var_password5checkEP3THD+0xd0)[0x688354] mysqld(_Z17sql_set_variablesP3THDP4ListI12set_var_baseE+0x68)[0x688494] mysqld(_Z21mysql_execute_commandP3THD+0x41a0)[0x67a170] mysqld(_Z11mysql_parseP3THDPKcjPS2_+0x282)[0x67f0ad] mysqld(_Z16dispatch_command19enum_server_commandP3THDPcj+0xbb7[0x67fdf8] mysqld(_Z10do_commandP3THD+0x24d)[0x6811b6] mysqld(handle_one_connection+0x11c)[0x66e05e] If resolution of function names for the trace fails, the trace contains less information: mysqld got signal 11; Attempting backtrace. You can use the following information to find out where mysqld died. If you see no messages after this, something went terribly wrong... stack_bottom = 0x41fd0110 thread_stack 0x40000 [0x9da402] [0x6648e9] [0x7f1a5af000f0] [0x7f1a5a10f0f2] [0x7412cb] [0x688354] [0x688494] [0x67a170] [0x67f0ad] [0x67fdf8] [0x6811b6] [0x66e05e] In the latter case, you can use the *Note `resolve_stack_dump': resolve-stack-dump. utility to determine where *Note `mysqld': mysqld. died by using the following procedure: 1. Copy the numbers from the stack trace to a file, for example `mysqld.stack'. The numbers should not include the surrounding square brackets: 0x9da402 0x6648e9 0x7f1a5af000f0 0x7f1a5a10f0f2 0x7412cb 0x688354 0x688494 0x67a170 0x67f0ad 0x67fdf8 0x6811b6 0x66e05e 2. Make a symbol file for the *Note `mysqld': mysqld. server: shell> nm -n libexec/mysqld > /tmp/mysqld.sym If *Note `mysqld': mysqld. is not linked statically, use the following command instead: shell> nm -D -n libexec/mysqld > /tmp/mysqld.sym If you want to decode C++ symbols, use the `--demangle', if available, to `nm'. If your version of `nm' does not have this option, you will need to use the `c++filt' command after the stack dump has been produced to demangle the C++ names. 3. Execute the following command: shell> resolve_stack_dump -s /tmp/mysqld.sym -n mysqld.stack If you were not able to include demangled C++ names in your symbol file, process the *Note `resolve_stack_dump': resolve-stack-dump. output using `c++filt': shell> resolve_stack_dump -s /tmp/mysqld.sym -n mysqld.stack | c++filt This prints out where *Note `mysqld': mysqld. died. If that does not help you find out why *Note `mysqld': mysqld. died, you should create a bug report and include the output from the preceding command with the bug report. However, in most cases it does not help us to have just a stack trace to find the reason for the problem. To be able to locate the bug or provide a workaround, in most cases we need to know the statement that killed *Note `mysqld': mysqld. and preferably a test case so that we can repeat the problem! See *Note bug-reports::.  File: manual.info, Node: using-log-files, Next: reproducible-test-case, Prev: using-stack-trace, Up: debugging-server 22.5.1.6 Using Server Logs to Find Causes of Errors in `mysqld' ............................................................... Note that before starting *Note `mysqld': mysqld. with the general query log enabled, you should check all your tables with *Note `myisamchk': myisamchk. See *Note server-administration::. If *Note `mysqld': mysqld. dies or hangs, you should start *Note `mysqld': mysqld. with the general query log enabled. See *Note query-log::. When *Note `mysqld': mysqld. dies again, you can examine the end of the log file for the query that killed *Note `mysqld': mysqld. If you use the default general query log file, the log is stored in the database directory as `HOST_NAME.log' In most cases it is the last query in the log file that killed *Note `mysqld': mysqld, but if possible you should verify this by restarting *Note `mysqld': mysqld. and executing the found query from the *Note `mysql': mysql. command-line tools. If this works, you should also test all complicated queries that didn't complete. You can also try the command *Note `EXPLAIN': explain. on all *Note `SELECT': select. statements that takes a long time to ensure that *Note `mysqld': mysqld. is using indexes properly. See *Note explain::. You can find the queries that take a long time to execute by starting *Note `mysqld': mysqld. with the slow query log enabled. See *Note slow-query-log::. If you find the text `mysqld restarted' in the error log file (normally named `hostname.err') you probably have found a query that causes *Note `mysqld': mysqld. to fail. If this happens, you should check all your tables with *Note `myisamchk': myisamchk. (see *Note server-administration::), and test the queries in the MySQL log files to see whether one fails. If you find such a query, try first upgrading to the newest MySQL version. If this doesn't help and you can't find anything in the `mysql' mail archive, you should report the bug to a MySQL mailing list. The mailing lists are described at `http://lists.mysql.com/', which also has links to online list archives. If you have started *Note `mysqld': mysqld. with `--myisam-recover', MySQL automatically checks and tries to repair `MyISAM' tables if they are marked as 'not closed properly' or 'crashed'. If this happens, MySQL writes an entry in the `hostname.err' file `'Warning: Checking table ...'' which is followed by `Warning: Repairing table' if the table needs to be repaired. If you get a lot of these errors, without *Note `mysqld': mysqld. having died unexpectedly just before, then something is wrong and needs to be investigated further. See *Note server-options::. It is not a good sign if *Note `mysqld': mysqld. did die unexpectedly, but in this case, you should not investigate the `Checking table...' messages, but instead try to find out why *Note `mysqld': mysqld. died.  File: manual.info, Node: reproducible-test-case, Prev: using-log-files, Up: debugging-server 22.5.1.7 Making a Test Case If You Experience Table Corruption .............................................................. If you get corrupted tables or if *Note `mysqld': mysqld. always fails after some update commands, you can test whether this bug is reproducible by doing the following: * Take down the MySQL daemon (with *Note `mysqladmin shutdown': mysqladmin.). * Make a backup of the tables (to guard against the very unlikely case that the repair does something bad). * Check all tables with *Note `myisamchk -s database/*.MYI': myisamchk. Repair any wrong tables with *Note `myisamchk -r database/TABLE.MYI': myisamchk. * Make a second backup of the tables. * Remove (or move away) any old log files from the MySQL data directory if you need more space. * Start *Note `mysqld': mysqld. with the binary log enabled. If you want to find a query that crashes *Note `mysqld': mysqld, you should start the server with both the general query log enabled as well. See *Note query-log::, and *Note binary-log::. * When you have gotten a crashed table, stop the `mysqld server'. * Restore the backup. * Restart the *Note `mysqld': mysqld. server *without* the binary log enabled. * Re-execute the commands with *Note `mysqlbinlog binary-log-file | mysql': mysqlbinlog. The binary log is saved in the MySQL database directory with the name `hostname-bin.NNNNNN'. * If the tables are corrupted again or you can get *Note `mysqld': mysqld. to die with the above command, you have found reproducible bug that should be easy to fix! FTP the tables and the binary log to `ftp://ftp.mysql.com/pub/mysql/upload/' and report it in our bugs database using the instructions given in *Note bug-reports::. (Please note that the `/pub/mysql/upload/' FTP directory is not listable, so you'll not see what you've uploaded in your FTP client.) If you are a support customer, you can use the MySQL Customer Support Center `https://support.mysql.com/' to alert the MySQL team about the problem and have it fixed as soon as possible. You can also use the script *Note `mysql_find_rows': mysql-find-rows. to just execute some of the update statements if you want to narrow down the problem.  File: manual.info, Node: debugging-client, Next: the-dbug-package, Prev: debugging-server, Up: porting 22.5.2 Debugging a MySQL Client ------------------------------- To be able to debug a MySQL client with the integrated debug package, you should configure MySQL with `--with-debug' or `--with-debug=full'. See *Note source-configuration-options::. Before running a client, you should set the `MYSQL_DEBUG' environment variable: shell> MYSQL_DEBUG=d:t:O,/tmp/client.trace shell> export MYSQL_DEBUG This causes clients to generate a trace file in `/tmp/client.trace'. If you have problems with your own client code, you should attempt to connect to the server and run your query using a client that is known to work. Do this by running *Note `mysql': mysql. in debugging mode (assuming that you have compiled MySQL with debugging on): shell> mysql --debug=d:t:O,/tmp/client.trace This provides useful information in case you mail a bug report. See *Note bug-reports::. If your client crashes at some 'legal' looking code, you should check that your `mysql.h' include file matches your MySQL library file. A very common mistake is to use an old `mysql.h' file from an old MySQL installation with new MySQL library.  File: manual.info, Node: the-dbug-package, Prev: debugging-client, Up: porting 22.5.3 The DBUG Package ----------------------- The MySQL server and most MySQL clients are compiled with the DBUG package originally created by Fred Fish. When you have configured MySQL for debugging, this package makes it possible to get a trace file of what the program is debugging. See *Note making-trace-files::. This section summaries the argument values that you can specify in debug options on the command line for MySQL programs that have been built with debugging support. For more information about programming with the DBUG package, see the DBUG manual in the `dbug' directory of MySQL source distributions. It is best to use a recent distribution to get the most updated DBUG manual. You use the debug package by invoking a program with the `--debug="..."' or the `-#...' option. Most MySQL programs have a default debug string that is used if you don't specify an option to `--debug'. The default trace file is usually `/tmp/program_name.trace' on Unix and `\program_name.trace' on Windows. The debug control string is a sequence of colon-separated fields as follows: ::...: Each field consists of a mandatory flag character followed by an optional ``,'' and comma-separated list of modifiers: flag[,modifier,modifier,...,modifier] The following table shows the currently recognized flag characters. Flag Description `d' Enable output from DBUG_ macros for the current state. May be followed by a list of keywords which selects output only for the DBUG macros with that keyword. An empty list of keywords implies output for all macros. `D' Delay after each debugger output line. The argument is the number of tenths of seconds to delay, subject to machine capabilities. For example, `-#D,20' specifies a delay of two seconds. `f' Limit debugging, tracing, and profiling to the list of named functions. Note that a null list disables all functions. The appropriate `d' or `t' flags must still be given; this flag only limits their actions if they are enabled. `F' Identify the source file name for each line of debug or trace output. `i' Identify the process with the PID or thread ID for each line of debug or trace output. `g' Enable profiling. Create a file called `dbugmon.out' containing information that can be used to profile the program. May be followed by a list of keywords that select profiling only for the functions in that list. A null list implies that all functions are considered. `L' Identify the source file line number for each line of debug or trace output. `n' Print the current function nesting depth for each line of debug or trace output. `N' Number each line of debug output. `o' Redirect the debugger output stream to the specified file. The default output is `stderr'. `O' Like `o', but the file is really flushed between each write. When needed, the file is closed and reopened between each write. `p' Limit debugger actions to specified processes. A process must be identified with the `DBUG_PROCESS' macro and match one in the list for debugger actions to occur. `P' Print the current process name for each line of debug or trace output. `r' When pushing a new state, do not inherit the previous state's function nesting level. Useful when the output is to start at the left margin. `S' Do function `_sanity(_file_,_line_)' at each debugged function until `_sanity()' returns something that differs from 0. (Mostly used with `safemalloc' to find memory leaks) `t' Enable function call/exit trace lines. May be followed by a list (containing only one modifier) giving a numeric maximum trace level, beyond which no output occurs for either debugging or tracing macros. The default is a compile time option. Some examples of debug control strings that might appear on a shell command line (the `-#' is typically used to introduce a control string to an application program) are: -#d:t -#d:f,main,subr1:F:L:t,20 -#d,input,output,files:n -#d:t:i:O,\\mysqld.trace In MySQL, common tags to print (with the `d' option) are `enter', `exit', `error', `warning', `info', and `loop'.  File: manual.info, Node: mysql-enterprise-monitor, Next: mysql-enterprise-backup, Prev: extending-mysql, Up: Top 23 MySQL Enterprise Monitor *************************** MySQL Enterprise Monitor is an enterprise monitoring system for MySQL that keeps an eye on your MySQL servers, notifies you of potential issues and problems, and advises you how to fix the issues. MySQL Enterprise Monitor can monitor all kinds of configurations, from a single MySQL server that is important to your business, all the way up to a huge farm of MySQL servers powering a busy web site. The following discussion briefly describes the basic components that make up the MySQL Enterprise Monitor product. For more information, see the MySQL Enterprise Monitor manual, available at `http://dev.mysql.com/doc/mysql-monitor/en/'. MySQL Enterprise Monitor components can be installed in various configurations depending on your own database and network topology, to give you the best combination of reliable and responsive monitoring data, with minimal overhead on the database server machines. A typical MySQL Enterprise Monitor installation consists of: * One or more MySQL servers that you want to monitor. MySQL Enterprise Monitor can monitor both Community and Enterprise MySQL server releases. * A MySQL Enterprise Monitor Agent for each monitored MySQL server. * A single MySQL Enterprise Service Manager, which collates information from the agents, and provides the user interface to the collected data. MySQL Enterprise Monitor is designed to monitor one or more MySQL servers. The monitoring information is collected by using an agent, _MySQL Enterprise Monitor Agent_. The agent communicates with the MySQL server that it monitors, collecting variables, status and health information, and sending this information to the MySQL Enterprise Service Manager. If you have multiple MySQL servers, then you have multiple MySQL Enterprise Monitor Agent processes monitoring each MySQL server. The information collected by the agent about each MySQL server you are monitoring is sent to the _MySQL Enterprise Service Manager_. This server collates all of the information from the agents. As it collates the information sent by the agents, the MySQL Enterprise Service Manager continually tests the collected data, comparing the status of the server to reasonable values. When thresholds are reached, the server can trigger an event (including an alarm and notification) to highlight a potential issue, such as low memory, high CPU usage, or more complex conditions such insufficient buffer sizes and status information. We call each test, with its associated threshold value, a _rule_. These rules, and the alarms and notifications, are each known as a _MySQL Enterprise Advisor_. Advisors form a critical part of the MySQL Enterprise Service Manager, as they provide warning information and troubleshooting advice about potential problems. The MySQL Enterprise Service Manager includes a web server, and you interact with it through any web browser. This interface, the MySQL Enterprise Dashboard, displays all of the information collected by the agents, and lets you view all of your servers and their current status as a group or individually. You control and configure all aspects of the service using the MySQL Enterprise Dashboard. The information supplied by the MySQL Enterprise Monitor Agent processes also includes statistical and query information, which you can view in the form of graphs. For example, you can view aspects such as server load, query numbers, or index usage information as a graph over time. The graph lets you pinpoint problems or potential issues on your server, and can help diagnose the impact from database or external problems (such as external system or network failure) by examining the data from a specific time interval. The MySQL Enterprise Monitor Agent can also be configured to collect detailed information about the queries executed on your server, including the row counts and performance times for executing each query. You can correlate the detailed query data with the graphical information to identify which queries were executing when you experienced a particularly high load, index or other issue. The query data is supported by a system called Query Analyzer, and the data can be presented in different ways depending on your needs.  File: manual.info, Node: mysql-enterprise-backup, Next: workbench, Prev: mysql-enterprise-monitor, Up: Top 24 MySQL Enterprise Backup ************************** The MySQL Enterprise Backup product performs hot backup (http://dev.mysql.com/doc/innodb-plugin/1.0/en/glossary.html#glos_hot_backup) operations for MySQL databases. The product is architected for efficient and reliable backups of tables created by the InnoDB storage engine (http://dev.mysql.com/doc/innodb-plugin/1.0/en/glossary.html#glos_innodb). For completeness, it can also back up tables from MyISAM and other storage engines. Hot backups (http://dev.mysql.com/doc/innodb-plugin/1.0/en/glossary.html#glos_hot_backup) are performed while the database is running. This type of backup does not block normal database operations, and it captures even changes that occur while the backup is happening. For these reasons, hot backups are desirable when your database `grows up' - when the data is large enough that the backup takes significant time, and when your data is important enough to your business so that you must capture every last change, without taking your application, web site, or web service offline. MySQL Enterprise Backup does a hot backup of all tables that use the InnoDB storage engine. For tables using MyISAM or other non-InnoDB storage engines, it does a `warm' backup, where the database continues to run, but those tables cannot be modified while being backed up. For efficient backup operations, you can designate InnoDB as the default storage engine for new tables, or convert existing tables to use the InnoDB storage engine. For more information, see the MySQL Enterprise Backup manual, available at `http://dev.mysql.com/doc/mysql-enterprise-backup/en/'.  File: manual.info, Node: workbench, Next: licenses-third-party, Prev: mysql-enterprise-backup, Up: Top 25 MySQL Workbench ****************** MySQL Workbench provides a graphical tool for working with MySQL Servers and databases. MySQL Workbench fully supports MySQL Server versions 5.1 and above. It is also compatible with MySQL Server 5.0, but not every feature of 5.0 may be supported. It does not support MySQL Server versions 4.x. The following discussion briefly describes MySQL Workbench capabilities. For more information, see the MySQL Workbench manual, available at `http://dev.mysql.com/doc/workbench/en/'. MySQL Workbench provides three main areas of functionality: * *SQL Development*: Enables you to create and manage connections to database servers. As well as enabling you to configure connection parameters, MySQL Workbench provides the capability to execute SQL queries on the database connections using the built-in SQL Editor. This functionality replaces that previously provided by the Query Browser standalone application. * *Data Modeling*: Enables you to create models of your database schema graphically, reverse and forward engineer between a schema and a live database, and edit all aspects of your database using the comprehensive Table Editor. The Table Editor provides easy-to-use facilities for editing Tables, Columns, Indexes, Triggers, Partitioning, Options, Inserts and Privileges, Routines and Views. * *Server Administration*: Enables you to create and administer server instances. This functionality replaces that previously provided by the MySQL Administrator standalone application. MySQL Workbench is available in two editions, the Community Edition and the Standard Edition. The Community Edition is available free of charge. The Standard Edition provides additional Enterprise features, such as database documentation generation, at low cost.  File: manual.info, Node: licenses-third-party, Next: faqs, Prev: workbench, Up: Top Appendix A Licenses for Third-Party Components ********************************************** * Menu: * license-ant-contrib:: Ant-Contrib License * license-antlr-3:: ANTLR 3 License * license-boost:: Boost Library License * license-dtoa:: `dtoa.c' License * license-libedit:: Editline Library (`libedit') License * license-findgtest-cmake:: `FindGTest.cmake' License * license-dbug:: Fred Fish's Dbug Library License * license-getarg:: `getarg' License * license-glib-proxy:: GLib License (for MySQL Proxy) * license-gnu-gpl-2-0:: GNU General Public License Version 2.0, June 1991 * license-gnu-lgpl-2-1:: GNU Lesser General Public License Version 2.1, February 1999 * license-gnu-libtool:: GNU Libtool License * license-gnu-readline:: GNU Readline License * license-google-io-rate-patch:: Google Controlling Master Thread I/O Rate Patch License * license-google-tcmalloc:: Google Perftools (TCMalloc utility) License * license-google-smp-patch:: Google SMP Patch License * license-lib-sql:: `lib_sql.cc' License * license-libevent:: `libevent' License * license-linux-pam:: Linux-PAM License * license-lpeg:: `LPeg' Library License * license-lua:: Lua (liblua) License * license-luafilesystem:: `LuaFileSystem' Library License * license-md5:: md5 (Message-Digest Algorithm 5) License * license-memcached:: `memcached' License * license-nt-servc:: nt_servc (Windows NT Service class library) License * license-openpam:: OpenPAM License * license-pcre:: PCRE License * license-percona-io-threads-patch:: Percona Multiple I/O Threads Patch License * license-regex:: RegEX-Spencer Library License * license-us-secure-hash:: RFC 3174 - US Secure Hash Algorithm 1 (SHA1) License * license-libstring:: Richard A. O'Keefe String Library License * license-sha1-in-c:: SHA-1 in C License * license-slf4j:: Simple Logging Facade for Java (SLF4J) License * license-zlib:: `zlib' License * license-zlib-net:: ZLIB.NET License The following is a list of the libraries we have included with the MySQL Server source and components used to test MySQL. We are thankful to all individuals that have created these. Some of the components require that their licensing terms be included in the documentation of products that include them. Cross references to these licensing terms are given with the applicable items in the list. * Bjorn Benson For his safe_malloc (memory checker) package which is used in when you build MySQL using one of the `BUILD/compile-*-debug' scripts or by manually setting the `-DSAFEMALLOC' flag. * GroupLens Research Project The MySQL Quality Assurance team would like to acknowledge the use of the MovieLens Data Sets (10 million ratings and 100,000 tags for 10681 movies by 71567 users) to help test MySQL products and to thank the GroupLens Research Project at the University of Minnesota for making the data sets available. *MySQL 5.1* * *Note license-dtoa:: * *Note license-libedit:: * *Note license-findgtest-cmake:: * *Note license-dbug:: * *Note license-getarg:: * *Note license-gnu-gpl-2-0:: * *Note license-gnu-libtool:: * *Note license-gnu-readline:: * *Note license-google-io-rate-patch:: * *Note license-google-smp-patch:: * *Note license-lib-sql:: * *Note license-md5:: * *Note license-nt-servc:: * *Note license-percona-io-threads-patch:: * *Note license-regex:: * *Note license-us-secure-hash:: * *Note license-libstring:: * *Note license-zlib:: *MySQL Cluster* * *Note license-antlr-3:: * *Note license-dtoa:: * *Note license-libedit:: * *Note license-findgtest-cmake:: * *Note license-dbug:: * *Note license-getarg:: * *Note license-gnu-gpl-2-0:: * *Note license-gnu-libtool:: * *Note license-gnu-readline:: * *Note license-google-io-rate-patch:: * *Note license-google-tcmalloc:: * *Note license-google-smp-patch:: * *Note license-lib-sql:: * *Note license-libevent:: * *Note license-linux-pam:: * *Note license-md5:: * *Note license-memcached:: * *Note license-nt-servc:: * *Note license-openpam:: * *Note license-percona-io-threads-patch:: * *Note license-regex:: * *Note license-us-secure-hash:: * *Note license-libstring:: * *Note license-sha1-in-c:: * *Note license-zlib:: *MySQL Connector/C* * *Note license-dbug:: * *Note license-regex:: * *Note license-us-secure-hash:: * *Note license-zlib:: *MySQL Connector/CPP* * *Note license-boost:: *MySQL Connector/J* * *Note license-ant-contrib:: * *Note license-slf4j:: *MySQL Connector/NET* * *Note license-us-secure-hash:: * *Note license-zlib:: * *Note license-zlib-net:: *MySQL Proxy* * *Note license-glib-proxy:: * *Note license-gnu-lgpl-2-1:: * *Note license-libevent:: * *Note license-lpeg:: * *Note license-lua:: * *Note license-luafilesystem:: * *Note license-pcre::  File: manual.info, Node: license-ant-contrib, Next: license-antlr-3, Prev: licenses-third-party, Up: licenses-third-party A.1 Ant-Contrib License ======================= The following software may be included in this product: Ant-Contrib Ant-Contrib Copyright (c) 2001-2003 Ant-Contrib project. All rights reserved. Licensed under the Apache 1.1 License Agreement, a copy of which is reproduced below. The Apache Software License, Version 1.1 Copyright (c) 2001-2003 Ant-Contrib project. All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. 3. The end-user documentation included with the redistribution, if any, must include the following acknowlegement: "This product includes software developed by the Ant-Contrib project (http://sourceforge.net/projects/ant-contrib)." Alternately, this acknowlegement may appear in the software itself, if and wherever such third-party acknowlegements normally appear. 4. The name Ant-Contrib must not be used to endorse or promote products derived from this software without prior written permission. For written permission, please contact ant-contrib-developers@lists.sourceforge.net. 5. Products derived from this software may not be called "Ant-Contrib" nor may "Ant-Contrib" appear in their names without prior written permission of the Ant-Contrib project. THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE ANT-CONTRIB PROJECT OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.  File: manual.info, Node: license-antlr-3, Next: license-boost, Prev: license-ant-contrib, Up: licenses-third-party A.2 ANTLR 3 License =================== The following software may be included in this product: ANTLR 3 ANTLR 3 License [The BSD License] Copyright (c) 2003-2007, Terence Parr All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: * Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. * Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. * Neither the name of the author nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.  File: manual.info, Node: license-boost, Next: license-dtoa, Prev: license-antlr-3, Up: licenses-third-party A.3 Boost Library License ========================= The following software may be included in this product: *Boost C++ Libraries* Use of any of this software is governed by the terms of the license below: Boost Software License - Version 1.0 - August 17th, 2003 Permission is hereby granted, free of charge, to any person or organization obtaining a copy of the software and accompanying documentation covered by this license (the "Software") to use, reproduce, display, distribute, execute, and transmit the Software, and to prepare derivative works of the Software, and to permit third-parties to whom the Software is furnished to do so, all subject to the following: The copyright notices in the Software and this entire statement, including the above license grant, this restriction and the following disclaimer, must be included in all copies of the Software, in whole or in part, and all derivative works of the Software, unless such copies or derivative works are solely in the form of machine-executable object code generated by a source language processor. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.  File: manual.info, Node: license-dtoa, Next: license-libedit, Prev: license-boost, Up: licenses-third-party A.4 `dtoa.c' License ==================== The following software may be included in this product: `dtoa.c' The author of this software is David M. Gay. Copyright (c) 1991, 2000, 2001 by Lucent Technologies. Permission to use, copy, modify, and distribute this software for any purpose without fee is hereby granted, provided that this entire notice is included in all copies of any software which is or includes a copy or modification of this software and in all copies of the supporting documentation for such software. THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR IMPLIED WARRANTY. IN PARTICULAR, NEITHER THE AUTHOR NOR LUCENT MAKES ANY REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE MERCHANTABILITY OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR PURPOSE.  File: manual.info, Node: license-libedit, Next: license-findgtest-cmake, Prev: license-dtoa, Up: licenses-third-party A.5 Editline Library (`libedit') License ======================================== The following software may be included in this product: Editline Library (libedit) Some files are: Copyright (c) 1992, 1993 The Regents of the University of California. All rights reserved. This code is derived from software contributed to Berkeley by Christos Zoulas of Cornell University. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. 3. Neither the name of the University nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission. THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. Some files are: Copyright (c) 2001 The NetBSD Foundation, Inc. All rights reserved. This code is derived from software contributed to The NetBSD Foundation by Anthony Mallet. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. Some files are: Copyright (c) 1997 The NetBSD Foundation, Inc. All rights reserved. This code is derived from software contributed to The NetBSD Foundation by Jaromir Dolecek. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. Some files are: Copyright (c) 1998 Todd C. Miller Permission to use, copy, modify, and distribute this software for any purpose with or without fee is hereby granted, provided that the above copyright notice and this permission notice appear in all copies. THE SOFTWARE IS PROVIDED "AS IS" AND TODD C. MILLER DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL TODD C. MILLER BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.  File: manual.info, Node: license-findgtest-cmake, Next: license-dbug, Prev: license-libedit, Up: licenses-third-party A.6 `FindGTest.cmake' License ============================= The following software may be included in this product: FindGTest.cmake helper script (part of CMake) Copyright 2009 Kitware, Inc. Copyright 2009 Philip Lowman Copyright 2009 Daniel Blezek Distributed under the OSI-approved BSD License (the "License"); see accompanying file Copyright.txt for details. This software is distributed WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the License for more information. ========================================================================== (To distributed this file outside of CMake, substitute the full License text for the above reference.) Thanks to Daniel Blezek for the GTEST_ADD_TESTS code Text of Copyright.txt mentioned above: CMake - Cross Platform Makefile Generator Copyright 2000-2009 Kitware, Inc., Insight Software Consortium All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: * Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. * Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. * Neither the names of Kitware, Inc., the Insight Software Consortium, nor the names of their contributors may be used to endorse or promote products derived from this software without specific prior written permission. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.  File: manual.info, Node: license-dbug, Next: license-getarg, Prev: license-findgtest-cmake, Up: licenses-third-party A.7 Fred Fish's Dbug Library License ==================================== The following software may be included in this product: Fred Fish's Dbug Library N O T I C E Copyright Abandoned, 1987, Fred Fish This previously copyrighted work has been placed into the public domain by the author and may be freely used for any purpose, private or commercial. Because of the number of inquiries I was receiving about the use of this product in commercially developed works I have decided to simply make it public domain to further its unrestricted use. I specifically would be most happy to see this material become a part of the standard Unix distributions by AT&T and the Berkeley Computer Science Research Group, and a standard part of the GNU system from the Free Software Foundation. I would appreciate it, as a courtesy, if this notice is left in all copies and derivative works. Thank you. The author makes no warranty of any kind with respect to this product and explicitly disclaims any implied warranties of mer- chantability or fitness for any particular purpose. The dbug_analyze.c file is subject to the following notice: Copyright June 1987, Binayak Banerjee All rights reserved. This program may be freely distributed under the same terms and conditions as Fred Fish's Dbug package.  File: manual.info, Node: license-getarg, Next: license-glib-proxy, Prev: license-dbug, Up: licenses-third-party A.8 `getarg' License ==================== The following software may be included in this product: `getarg' Function (`getarg.h', `getarg.c' files) Copyright (c) 1997 - 2000 Kungliga Tekniska Ho"gskolan (Royal Institute of Technology, Stockholm, Sweden). All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. 3. Neither the name of the Institute nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission. THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.  File: manual.info, Node: license-glib-proxy, Next: license-gnu-gpl-2-0, Prev: license-getarg, Up: licenses-third-party A.9 GLib License (for MySQL Proxy) ================================== The following software may be included in this product: GLib You are receiving a copy of the GLib library in both source and object code in the following [proxy install dir]/lib/ and [proxy install dir]/licenses/lgpl folders. The terms of the Oracle license do NOT apply to the GLib library; it is licensed under the following license, separately from the Oracle programs you receive. If you do not wish to install this library, you may create an "exclude" file and run tar with the X option, as in the following example, but the Oracle program might not operate properly or at all without the library: tar -xvfX where the exclude-file contains, e.g.: /lib/libglib-2.0.so.0.1600.6 /lib/libglib-2.0.so.0 ... Example: tar -xvfX mysql-proxy-0.8.1-solaris10-x86-64bit.tar.gz Exclude Exclude File: mysql-proxy-0.8.1-solaris10-x86-64bit/lib/libglib-2.0.so mysql-proxy-0.8.1-solaris10-x86-64bit/lib/libglib-2.0.so.0 mysql-proxy-0.8.1-solaris10-x86-64bit/lib/libglib-2.0.so.0.1600.6 mysql-proxy-0.8.1-solaris10-x86-64bit/lib/libgmodule-2.0.so mysql-proxy-0.8.1-solaris10-x86-64bit/lib/libgmodule-2.0.so.0 mysql-proxy-0.8.1-solaris10-x86-64bit/lib/libgmodule-2.0.so.0.1600.6 mysql-proxy-0.8.1-solaris10-x86-64bit/lib/libgthread-2.0.so mysql-proxy-0.8.1-solaris10-x86-64bit/lib/libgthread-2.0.so.0 mysql-proxy-0.8.1-solaris10-x86-64bit/lib/libgthread-2.0.so.0.1600.6 mysql-proxy-0.8.1-solaris10-x86-64bit/licenses/lgpl/glib-2.16.6.tar.gz This component is licensed under *Note license-gnu-lgpl-2-1::.  File: manual.info, Node: license-gnu-gpl-2-0, Next: license-gnu-lgpl-2-1, Prev: license-glib-proxy, Up: licenses-third-party A.10 GNU General Public License Version 2.0, June 1991 ====================================================== The following applies to all products licensed under the GNU General Public License, Version 2.0: You may not use the identified files except in compliance with the GNU General Public License, Version 2.0 (the "License.") You may obtain a copy of the License at http://www.gnu.org/licenses/gpl-2.0.txt. A copy of the license is also reproduced below. Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License. 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If the program is interactive, make it output a short notice like this when it starts in an interactive mode: Gnomovision version 69, Copyright (C) year name of author Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type 'show w'. This is free software, and you are welcome to redistribute it under certain conditions; type 'show c' for details. The hypothetical commands 'show w' and 'show c' should show the appropriate parts of the General Public License. Of course, the commands you use may be called something other than 'show w' and 'show c'; they could even be mouse-clicks or menu items--whatever suits your program. You should also get your employer (if you work as a programmer) or your school, if any, to sign a "copyright disclaimer" for the program, if necessary. 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File: manual.info, Node: license-gnu-lgpl-2-1, Next: license-gnu-libtool, Prev: license-gnu-gpl-2-0, Up: licenses-third-party A.11 GNU Lesser General Public License Version 2.1, February 1999 ================================================================= The following applies to all products licensed under the GNU Lesser General Public License, Version 2.1: You may not use the identified files except in compliance with the GNU Lesser General Public License, Version 2.1 (the "License"). You may obtain a copy of the License at http://www.gnu.org/licenses/lgpl-2.1.html. A copy of the license is also reproduced below. Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License. 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File: manual.info, Node: license-gnu-libtool, Next: license-gnu-readline, Prev: license-gnu-lgpl-2-1, Up: licenses-third-party A.12 GNU Libtool License ======================== The following software may be included in this product: GNU Libtool (The GNU Portable Library Tool) If you are receiving a copy of the Oracle software in source code, you are also receiving a copy of two files (ltmain.sh and ltdl.h) generated by the GNU Libtool in source code. If you received the Oracle software under a license other than a commercial (non-GPL) license, then the terms of the Oracle license do NOT apply to these files from GNU Libtool; they are licensed under the following licenses, separately from the Oracle programs you receive. 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IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.  File: manual.info, Node: license-google-tcmalloc, Next: license-google-smp-patch, Prev: license-google-io-rate-patch, Up: licenses-third-party A.15 Google Perftools (TCMalloc utility) License ================================================ The following software may be included in this product: Google Perftools (TCMalloc utility) Copyright (c) 1998-2006, Google Inc. All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: * Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. * Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. * Neither the name of Google Inc. nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.  File: manual.info, Node: license-google-smp-patch, Next: license-lib-sql, Prev: license-google-tcmalloc, Up: licenses-third-party A.16 Google SMP Patch License ============================= The following software may be included in this product: Google SMP Patch Google SMP patch Copyright (c) 2008, Google Inc. All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: * Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. * Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. * Neither the name of the Google Inc. nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.  File: manual.info, Node: license-lib-sql, Next: license-libevent, Prev: license-google-smp-patch, Up: licenses-third-party A.17 `lib_sql.cc' License ========================= The following software may be included in this product: `lib_sql.cc' Copyright (c) 2000 SWsoft company This material is provided "as is", with absolutely no warranty expressed or implied. Any use is at your own risk. Permission to use or copy this software for any purpose is hereby granted without fee, provided the above notices are retained on all copies. Permission to modify the code and to distribute modified code is granted, provided the above notices are retained, and a notice that the code was modified is included with the above copyright notice. This code was modified by the MySQL team.  File: manual.info, Node: license-libevent, Next: license-linux-pam, Prev: license-lib-sql, Up: licenses-third-party A.18 `libevent' License ======================= The following software may be included in this product: libevent Copyright (c) 2000-2007 Niels Provos All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. 3. The name of the author may not be used to endorse or promote products derived from this software without specific prior written permission. THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE  File: manual.info, Node: license-linux-pam, Next: license-lpeg, Prev: license-libevent, Up: licenses-third-party A.19 Linux-PAM License ====================== The following software may be included in this product: Linux-PAM (pam-devel, Pluggable authentication modules for Linux) Copyright Theodore Ts'o, 1996. All rights reserved. (For the avoidance of doubt, Oracle uses and distributes this component under the terms below and elects not to do so under the GPL even though the GPL is referenced as an option below.) Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: 1. Redistributions of source code must retain the above copyright notice, and the entire permission notice in its entirety, including the disclaimer of warranties. 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. 3. The name of the author may not be used to endorse or promote products derived from this software without specific prior written permission. ALTERNATIVELY, this product may be distributed under the terms of the GNU Public License, in which case the provisions of the GPL are required INSTEAD OF the above restrictions. (This clause is necessary due to a potential bad interaction between the GPL and the restrictions contained in a BSD-style copyright.) THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.  File: manual.info, Node: license-lpeg, Next: license-lua, Prev: license-linux-pam, Up: licenses-third-party A.20 `LPeg' Library License =========================== The following software may be included in this product: LPeg Use of any of this software is governed by the terms of the license below: Copyright (C) 2008 Lua.org, PUC-Rio. Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.  File: manual.info, Node: license-lua, Next: license-luafilesystem, Prev: license-lpeg, Up: licenses-third-party A.21 Lua (liblua) License ========================= The following software may be included in this product: Lua (liblua) Copyright (C) 1994-2008 Lua.org, PUC-Rio. Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.  File: manual.info, Node: license-luafilesystem, Next: license-md5, Prev: license-lua, Up: licenses-third-party A.22 `LuaFileSystem' Library License ==================================== The following software may be included in this product: LuaFileSystem Copyright (C) 2003 Kepler Project. Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.  File: manual.info, Node: license-md5, Next: license-memcached, Prev: license-luafilesystem, Up: licenses-third-party A.23 md5 (Message-Digest Algorithm 5) License ============================================= The following software may be included in this product: md5 (Message-Digest Algorithm 5) This code implements the MD5 message-digest algorithm. The algorithm is due to Ron Rivest. This code was written by Colin Plumb in 1993, no copyright is claimed. This code is in the public domain; do with it what you wish. Equivalent code is available from RSA Data Security, Inc. This code has been tested against that, and is equivalent, except that you don't need to include two pages of legalese with every copy. The code has been modified by Mikael Ronstroem to handle calculating a hash value of a key that is always a multiple of 4 bytes long. Word 0 of the calculated 4-word hash value is returned as the hash value.  File: manual.info, Node: license-memcached, Next: license-nt-servc, Prev: license-md5, Up: licenses-third-party A.24 `memcached' License ======================== The following software may be included in this product: memcached Copyright (c) 2003, Danga Interactive, Inc. All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: * Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. * Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. * Neither the name of the Danga Interactive nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.  File: manual.info, Node: license-nt-servc, Next: license-openpam, Prev: license-memcached, Up: licenses-third-party A.25 nt_servc (Windows NT Service class library) License ======================================================== The following software may be included in this product: nt_servc (Windows NT Service class library) Windows NT Service class library Copyright Abandoned 1998 Irena Pancirov - Irnet Snc This file is public domain and comes with NO WARRANTY of any kind  File: manual.info, Node: license-openpam, Next: license-pcre, Prev: license-nt-servc, Up: licenses-third-party A.26 OpenPAM License ==================== The following software may be included in this product: OpenPAM Copyright (c) 2002-2003 Networks Associates Technology, Inc. Copyright (c) 2004-2007 Dag-Erling Sm/orgrav All rights reserved. This software was developed for the FreeBSD Project by ThinkSec AS and Network Associates Laboratories, the Security Research Division of Network Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the DARPA CHATS research program. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. 3. The name of the author may not be used to endorse or promote products derived from this software without specific prior written permission. THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.  File: manual.info, Node: license-pcre, Next: license-percona-io-threads-patch, Prev: license-openpam, Up: licenses-third-party A.27 PCRE License ================= The following software may be included in this product: PCRE (Perl Compatible Regular Expressions) Library PCRE LICENCE PCRE is a library of functions to support regular expressions whose syntax and semantics are as close as possible to those of the Perl 5 language. Release 7 of PCRE is distributed under the terms of the "BSD" licence, as specified below. The documentation for PCRE, supplied in the "doc" directory, is distributed under the same terms as the software itself. The basic library functions are written in C and are freestanding. Also included in the distribution is a set of C++ wrapper functions. THE BASIC LIBRARY FUNCTIONS --------------------------- Written by: Philip Hazel Email local part: ph10 Email domain: cam.ac.uk University of Cambridge Computing Service, Cambridge, England. Phone: +44 1223 334714. Copyright (c) 1997-2006 University of Cambridge All rights reserved. THE C++ WRAPPER FUNCTIONS ------------------------- Contributed by: Google Inc. Copyright (c) 2006, Google Inc. All rights reserved. THE "BSD" LICENCE ----------------- Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: * Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. * Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. * Neither the name of the University of Cambridge nor the name of Google Inc. nor the names of their contributors may be used to endorse or promote products derived from this software without specific prior written permission. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. End  File: manual.info, Node: license-percona-io-threads-patch, Next: license-regex, Prev: license-pcre, Up: licenses-third-party A.28 Percona Multiple I/O Threads Patch License =============================================== The following software may be included in this product: Percona Multiple I/O threads patch Copyright (c) 2008, 2009 Percona Inc All rights reserved. Redistribution and use of this software in source and binary forms, with or without modification, are permitted provided that the following conditions are met: * Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. * Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. * Neither the name of Percona Inc. nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission of Percona Inc. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.  File: manual.info, Node: license-regex, Next: license-us-secure-hash, Prev: license-percona-io-threads-patch, Up: licenses-third-party A.29 RegEX-Spencer Library License ================================== The following software may be included in this product: Henry Spencer's Regular-Expression Library (RegEX-Spencer) Copyright 1992, 1993, 1994 Henry Spencer. All rights reserved. This software is not subject to any license of the American Telephone and Telegraph Company or of the Regents of the University of California. Permission is granted to anyone to use this software for any purpose on any computer system, and to alter it and redistribute it, subject to the following restrictions: 1. The author is not responsible for the consequences of use of this software, no matter how awful, even if they arise from flaws in it. 2. The origin of this software must not be misrepresented, either by explicit claim or by omission. Since few users ever read sources, credits must appear in the documentation. 3. Altered versions must be plainly marked as such, and must not be misrepresented as being the original software. Since few users ever read sources, credits must appear in the documentation. 4. This notice may not be removed or altered.  File: manual.info, Node: license-us-secure-hash, Next: license-libstring, Prev: license-regex, Up: licenses-third-party A.30 RFC 3174 - US Secure Hash Algorithm 1 (SHA1) License ========================================================= The following software may be included in this product: RFC 3174 - US Secure Hash Algorithm 1 (SHA1) RFC 3174 - US Secure Hash Algorithm 1 (SHA1) Copyright (C) The Internet Society (2001). All Rights Reserved. This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implementation may be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works. However, this document itself may not be modified in any way, such as by removing the copyright notice or references to the Internet Society or other Internet organizations, except as needed for the purpose of developing Internet standards in which case the procedures for copyrights defined in the Internet Standards process must be followed, or as required to translate it into languages other than English. The limited permissions granted above are perpetual and will not be revoked by the Internet Society or its successors or assigns. This document and the information contained herein is provided on an "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Acknowledgement Funding for the RFC Editor function is currently provided by the Internet Society.  File: manual.info, Node: license-libstring, Next: license-sha1-in-c, Prev: license-us-secure-hash, Up: licenses-third-party A.31 Richard A. O'Keefe String Library License ============================================== The following software may be included in this product: Richard A. O'Keefe String Library The Richard O'Keefe String Library is subject to the following notice: These files are in the public domain. This includes getopt.c, which is the work of Henry Spencer, University of Toronto Zoology, who says of it "None of this software is derived from Bell software. I had no access to the source for Bell's versions at the time I wrote it. This software is hereby explicitly placed in the public domain. It may be used for any purpose on any machine by anyone." I would greatly prefer it if *my* material received no military use. The t_ctype.h file is subject to the following notice: Copyright (C) 1998, 1999 by Pruet Boonma, all rights reserved. Copyright (C) 1998 by Theppitak Karoonboonyanan, all rights reserved. Permission to use, copy, modify, distribute and sell this software and its documentation for any purpose is hereby granted without fee, provided that the above copyright notice appear in all copies. Smaphan Raruenrom and Pruet Boonma makes no representations about the suitability of this software for any purpose. It is provided "as is" without express or implied warranty.  File: manual.info, Node: license-sha1-in-c, Next: license-slf4j, Prev: license-libstring, Up: licenses-third-party A.32 SHA-1 in C License ======================= The following software may be included in this product: SHA-1 in C SHA-1 in C By Steve Reid 100% Public Domain  File: manual.info, Node: license-slf4j, Next: license-zlib, Prev: license-sha1-in-c, Up: licenses-third-party A.33 Simple Logging Facade for Java (SLF4J) License =================================================== The following software may be included in this product: Simple Logging Facade for Java (SLF4J) Copyright (c) 2004-2008 QOS.ch All rights reserved. Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.  File: manual.info, Node: license-zlib, Next: license-zlib-net, Prev: license-slf4j, Up: licenses-third-party A.34 `zlib' License =================== The following software may be included in this product: zlib Oracle gratefully acknowledges the contributions of Jean-loup Gailly and Mark Adler in creating the zlib general purpose compression library which is used in this product. zlib.h -- interface of the 'zlib' general purpose compression library version 1.2.3, July 18th, 2005 Copyright (C) 1995-2005 Jean-loup Gailly and Mark Adler zlib.h -- interface of the 'zlib' general purpose compression library version 1.2.5, April 19th, 2010 Copyright (C) 1995-2010 Jean-loup Gailly and Mark Adler This software is provided 'as-is', without any express or implied warranty. In no event will the authors be held liable for any damages arising from the use of this software. Permission is granted to anyone to use this software for any purpose,including commercial applications, and to alter it and redistribute it freely, subject to the following restrictions: 1. The origin of this software must not be misrepresented; you must not claim that you wrote the original software. If you use this software in a product, an acknowledgment in the product documentation would be appreciated but is not required. 2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software. 3. This notice may not be removed or altered from any source distribution. Jean-loup Gailly jloup@gzip.org Mark Adler madler@alumni.caltech.edu  File: manual.info, Node: license-zlib-net, Prev: license-zlib, Up: licenses-third-party A.35 ZLIB.NET License ===================== The following software may be included in this product: ZLIB.NET Copyright (c) 2006-2007, ComponentAce http://www.componentace.com All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: * Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. * Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. * Neither the name of ComponentAce nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.  File: manual.info, Node: faqs, Next: error-handling, Prev: licenses-third-party, Up: Top Appendix B MySQL 5.1 Frequently Asked Questions *********************************************** * Menu: * faqs-general:: MySQL 5.1 FAQ: General * faqs-storage-engines:: MySQL 5.1 FAQ: Storage Engines * faqs-sql-modes:: MySQL 5.1 FAQ: Server SQL Mode * faqs-stored-procs:: MySQL 5.1 FAQ: Stored Procedures and Functions * faqs-triggers:: MySQL 5.1 FAQ: Triggers * faqs-views:: MySQL 5.1 FAQ: Views * faqs-information-schema:: MySQL 5.1 FAQ: `INFORMATION_SCHEMA' * faqs-migration:: MySQL 5.1 FAQ: Migration * faqs-security:: MySQL 5.1 FAQ: Security * faqs-mysql-cluster:: MySQL 5.1 FAQ: MySQL Cluster * faqs-cjk:: MySQL 5.1 FAQ: MySQL Chinese, Japanese, and Korean Character Sets * faqs-connectors-apis:: MySQL 5.1 FAQ: Connectors & APIs * faqs-replication:: MySQL 5.1 FAQ: Replication * faqs-mysql-drbd-heartbeat:: MySQL 5.1 FAQ: MySQL, DRBD, and Heartbeat  File: manual.info, Node: faqs-general, Next: faqs-storage-engines, Prev: faqs, Up: faqs B.1 MySQL 5.1 FAQ: General ========================== *Questions* * B.1.1: Which version of MySQL is production-ready (GA)? * B.1.2: What is the state of development (non-GA) versions? * B.1.3: Can MySQL 5.1 do subqueries? * B.1.4: Can MySQL 5.1 perform multiple-table inserts, updates, and deletes? * B.1.5: Does MySQL 5.1 have a Query Cache? Does it work on Server, Instance or Database? * B.1.6: Does MySQL 5.1 have Sequences? * B.1.7: Does MySQL 5.1 have a `NOW()' function with fractions of seconds? * B.1.8: Does MySQL 5.1 work with multi-core processors? * B.1.9: Why do I see multiple processes for `mysqld'? * B.1.10: Have there been there any improvements in error reporting when foreign keys fail? Does MySQL now report which column and reference failed? * B.1.11: Can MySQL 5.1 perform ACID transactions? *Questions and Answers* *B.1.1: ** Which version of MySQL is production-ready (GA)? * Currently, both MySQL 5.0 and MySQL 5.1 are supported for production use. MySQL 5.0 achieved General Availability (GA) status with MySQL 5.0.15, which was released for production use on 19 October 2005. MySQL 5.1 achieved General Availability (GA) status with MySQL 5.1.30, which was released for production use on 14 November 2008. *B.1.2: ** What is the state of development (non-GA) versions? * MySQL follows a milestone release model that introduces pre-production-quality features and stabilizes them to release quality (see `http://forge.mysql.com/wiki/Development_Cycle'). This process then repeats, so releases cycle between pre-production and release quality status. Please check the change logs to identify the status of a given release. MySQL 5.4 was a development series. Work on this series has ceased. MySQL 5.5 is being actively developed using the milestone release methodology described above. MySQL 5.6 is being actively developed using the milestone release methodology described above. MySQL 6.0 was a development series. Work on this series has ceased. *B.1.3: ** Can MySQL 5.1 do subqueries? * Yes. See *Note subqueries::. *B.1.4: ** Can MySQL 5.1 perform multiple-table inserts, updates, and deletes? * Yes. For the syntax required to perform multiple-table updates, see *Note update::; for that required to perform multiple-table deletes, see *Note delete::. A multiple-table insert can be accomplished using a trigger whose `FOR EACH ROW' clause contains multiple *Note `INSERT': insert. statements within a `BEGIN ... END' block. See *Note triggers::. *B.1.5: ** Does MySQL 5.1 have a Query Cache? Does it work on Server, Instance or Database? * Yes. The query cache operates on the server level, caching complete result sets matched with the original query string. If an exactly identical query is made (which often happens, particularly in web applications), no parsing or execution is necessary; the result is sent directly from the cache. Various tuning options are available. See *Note query-cache::. *B.1.6: ** Does MySQL 5.1 have Sequences? * No. However, MySQL has an `AUTO_INCREMENT' system, which in MySQL 5.1 can also handle inserts in a multi-master replication setup. With the `auto_increment_increment' and `auto_increment_offset' system variables, you can set each server to generate auto-increment values that don't conflict with other servers. The `auto_increment_increment' value should be greater than the number of servers, and each server should have a unique offset. *B.1.7: ** Does MySQL 5.1 have a `NOW()' function with fractions of seconds? * No. This is on the MySQL roadmap as a `rolling feature'. This means that it is not a flagship feature, but will be implemented, development time permitting. Specific customer demand may change this scheduling. However, MySQL does parse time strings with a fractional component. See *Note time::. *B.1.8: ** Does MySQL 5.1 work with multi-core processors? * Yes. MySQL is fully multi-threaded, and will make use of multiple CPUs, provided that the operating system supports them. *B.1.9: ** Why do I see multiple processes for `mysqld'? * When using LinuxThreads, you should see a minimum of three *Note `mysqld': mysqld. processes running. These are in fact threads. There is one thread for the LinuxThreads manager, one thread to handle connections, and one thread to handle alarms and signals. *B.1.10: ** Have there been there any improvements in error reporting when foreign keys fail? Does MySQL now report which column and reference failed? * The foreign key support in `InnoDB' has seen improvements in each major version of MySQL. Foreign key support generic to all storage engines is scheduled for MySQL 6.x; this should resolve any inadequacies in the current storage engine specific implementation. *B.1.11: ** Can MySQL 5.1 perform ACID transactions? * Yes. All current MySQL versions support transactions. The `InnoDB' storage engine offers full ACID transactions with row-level locking, multi-versioning, nonlocking repeatable reads, and all four SQL standard isolation levels. The *Note `NDB': mysql-cluster. storage engine supports the `READ COMMITTED' transaction isolation level only.  File: manual.info, Node: faqs-storage-engines, Next: faqs-sql-modes, Prev: faqs-general, Up: faqs B.2 MySQL 5.1 FAQ: Storage Engines ================================== *Questions* * B.2.1: Where can I obtain complete documentation for MySQL storage engines and the pluggable storage engine architecture? * B.2.2: Are there any new storage engines in MySQL 5.1? * B.2.3: Have any storage engines been removed in MySQL 5.1? * B.2.4: What are the unique benefits of the `ARCHIVE' storage engine? * B.2.5: Do the new features in MySQL 5.1 apply to all storage engines? *Questions and Answers* *B.2.1: ** Where can I obtain complete documentation for MySQL storage engines and the pluggable storage engine architecture? * See *Note storage-engines::. That chapter contains information about all MySQL storage engines except for the *Note `NDB': mysql-cluster. storage engine used for MySQL Cluster; *Note `NDB': mysql-cluster. is covered in *Note mysql-cluster::. *B.2.2: ** Are there any new storage engines in MySQL 5.1? * Yes, the *Note `IBMDB2I': se-db2. storage engine is included in the IBM i5/OS (TAR packages) and IBM i5/OS (SAVF packages). Also, there have been significant improvements in existing storage engines, in particular for the *Note `NDB': mysql-cluster. storage engine that forms the basis for MySQL Cluster. Also, the `InnoDB Plugin' is available as an alternative to the built-in version of the `InnoDB' storage engine. *B.2.3: ** Have any storage engines been removed in MySQL 5.1? * Yes. MySQL 5.1 no longer supports the `BDB' storage engine. Any existing `BDB' tables should be converted to another storage engine before upgrading to MySQL 5.1. *B.2.4: ** What are the unique benefits of the `ARCHIVE' storage engine? * The `ARCHIVE' storage engine is ideally suited for storing large amounts of data without indexes; it has a very small footprint, and performs selects using table scans. See *Note archive-storage-engine::, for details. *B.2.5: ** Do the new features in MySQL 5.1 apply to all storage engines? * The general new features such as views, stored procedures, triggers, `INFORMATION_SCHEMA', precision math (*Note `DECIMAL': numeric-types. column type), and the *Note `BIT': numeric-types. column type, apply to all storage engines. There are also additions and changes for specific storage engines.  File: manual.info, Node: faqs-sql-modes, Next: faqs-stored-procs, Prev: faqs-storage-engines, Up: faqs B.3 MySQL 5.1 FAQ: Server SQL Mode ================================== *Questions* * B.3.1: What are server SQL modes? * B.3.2: How many server SQL modes are there? * B.3.3: How do you determine the server SQL mode? * B.3.4: Is the mode dependent on the database or connection? * B.3.5: Can the rules for strict mode be extended? * B.3.6: Does strict mode impact performance? * B.3.7: What is the default server SQL mode when My SQL 5.1 is installed? *Questions and Answers* *B.3.1: ** What are server SQL modes? * Server SQL modes define what SQL syntax MySQL should support and what kind of data validation checks it should perform. This makes it easier to use MySQL in different environments and to use MySQL together with other database servers. The MySQL Server apply these modes individually to different clients. For more information, see *Note server-sql-mode::. *B.3.2: ** How many server SQL modes are there? * Each mode can be independently switched on and off. See *Note server-sql-mode::, for a complete list of available modes. *B.3.3: ** How do you determine the server SQL mode? * You can set the default SQL mode (for *Note `mysqld': mysqld. startup) with the `--sql-mode' option. Using the statement *Note `SET [GLOBAL|SESSION] sql_mode='MODES'': set-option, you can change the settings from within a connection, either locally to the connection, or to take effect globally. You can retrieve the current mode by issuing a `SELECT @@sql_mode' statement. *B.3.4: ** Is the mode dependent on the database or connection? * A mode is not linked to a particular database. Modes can be set locally to the session (connection), or globally for the server. you can change these settings using *Note `SET [GLOBAL|SESSION] sql_mode='MODES'': set-option. *B.3.5: ** Can the rules for strict mode be extended? * When we refer to _strict mode_, we mean a mode where at least one of the modes `TRADITIONAL', `STRICT_TRANS_TABLES', or `STRICT_ALL_TABLES' is enabled. Options can be combined, so you can add restrictions to a mode. See *Note server-sql-mode::, for more information. *B.3.6: ** Does strict mode impact performance? * The intensive validation of input data that some settings requires more time than if the validation is not done. While the performance impact is not that great, if you do not require such validation (perhaps your application already handles all of this), then MySQL gives you the option of leaving strict mode disabled. However--if you do require it--strict mode can provide such validation. *B.3.7: ** What is the default server SQL mode when My SQL 5.1 is installed? * By default, no special modes are enabled. See *Note server-sql-mode::, for information about all available modes and MySQL's default behavior.  File: manual.info, Node: faqs-stored-procs, Next: faqs-triggers, Prev: faqs-sql-modes, Up: faqs B.4 MySQL 5.1 FAQ: Stored Procedures and Functions ================================================== *Questions* * B.4.1: Does MySQL 5.1 support stored procedures and functions? * B.4.2: Where can I find documentation for MySQL stored procedures and stored functions? * B.4.3: Is there a discussion forum for MySQL stored procedures? * B.4.4: Where can I find the ANSI SQL 2003 specification for stored procedures? * B.4.5: How do you manage stored routines? * B.4.6: Is there a way to view all stored procedures and stored functions in a given database? * B.4.7: Where are stored procedures stored? * B.4.8: Is it possible to group stored procedures or stored functions into packages? * B.4.9: Can a stored procedure call another stored procedure? * B.4.10: Can a stored procedure call a trigger? * B.4.11: Can a stored procedure access tables? * B.4.12: Do stored procedures have a statement for raising application errors? * B.4.13: Do stored procedures provide exception handling? * B.4.14: Can MySQL 5.1 stored routines return result sets? * B.4.15: Is `WITH RECOMPILE' supported for stored procedures? * B.4.16: Is there a MySQL equivalent to using `mod_plsql' as a gateway on Apache to talk directly to a stored procedure in the database? * B.4.17: Can I pass an array as input to a stored procedure? * B.4.18: Can I pass a cursor as an `IN' parameter to a stored procedure? * B.4.19: Can I return a cursor as an `OUT' parameter from a stored procedure? * B.4.20: Can I print out a variable's value within a stored routine for debugging purposes? * B.4.21: Can I commit or roll back transactions inside a stored procedure? * B.4.22: Do MySQL 5.1 stored procedures and functions work with replication? * B.4.23: Are stored procedures and functions created on a master server replicated to a slave? * B.4.24: How are actions that take place inside stored procedures and functions replicated? * B.4.25: Are there special security requirements for using stored procedures and functions together with replication? * B.4.26: What limitations exist for replicating stored procedure and function actions? * B.4.27: Do the preceding limitations affect MySQL's ability to do point-in-time recovery? * B.4.28: What is being done to correct the aforementioned limitations? *Questions and Answers* *B.4.1: ** Does MySQL 5.1 support stored procedures and functions? * Yes. MySQL 5.1 supports two types of stored routines--stored procedures and stored functions. *B.4.2: ** Where can I find documentation for MySQL stored procedures and stored functions? * See *Note stored-routines::. *B.4.3: ** Is there a discussion forum for MySQL stored procedures? * Yes. See http://forums.mysql.com/list.php?98 (http://forums.mysql.com/list.php?98). *B.4.4: ** Where can I find the ANSI SQL 2003 specification for stored procedures? * Unfortunately, the official specifications are not freely available (ANSI makes them available for purchase). However, there are books--such as `SQL-99 Complete, Really' by Peter Gulutzan and Trudy Pelzer--which give a comprehensive overview of the standard, including coverage of stored procedures. *B.4.5: ** How do you manage stored routines? * It is always good practice to use a clear naming scheme for your stored routines. You can manage stored procedures with `CREATE [FUNCTION|PROCEDURE]', `ALTER [FUNCTION|PROCEDURE]', `DROP [FUNCTION|PROCEDURE]', and `SHOW CREATE [FUNCTION|PROCEDURE]'. You can obtain information about existing stored procedures using the *Note `ROUTINES': routines-table. table in the `INFORMATION_SCHEMA' database (see *Note routines-table::). *B.4.6: ** Is there a way to view all stored procedures and stored functions in a given database? * Yes. For a database named DBNAME, use this query on the *Note `INFORMATION_SCHEMA.ROUTINES': routines-table. table: SELECT ROUTINE_TYPE, ROUTINE_NAME FROM INFORMATION_SCHEMA.ROUTINES WHERE ROUTINE_SCHEMA='DBNAME'; For more information, see *Note routines-table::. The body of a stored routine can be viewed using *Note `SHOW CREATE FUNCTION': show-create-function. (for a stored function) or *Note `SHOW CREATE PROCEDURE': show-create-procedure. (for a stored procedure). See *Note show-create-procedure::, for more information. *B.4.7: ** Where are stored procedures stored? * In the `proc' table of the `mysql' system database. However, you should not access the tables in the system database directly. Instead, use *Note `SHOW CREATE FUNCTION': show-create-function. to obtain information about stored functions, and *Note `SHOW CREATE PROCEDURE': show-create-procedure. to obtain information about stored procedures. See *Note show-create-procedure::, for more information about these statements. You can also query the *Note `ROUTINES': routines-table. table in the `INFORMATION_SCHEMA' database--see *Note routines-table::, for information about this table. *B.4.8: ** Is it possible to group stored procedures or stored functions into packages? * No. This is not supported in MySQL 5.1. *B.4.9: ** Can a stored procedure call another stored procedure? * Yes. *B.4.10: ** Can a stored procedure call a trigger? * A stored procedure can execute an SQL statement, such as an *Note `UPDATE': update, that causes a trigger to activate. *B.4.11: ** Can a stored procedure access tables? * Yes. A stored procedure can access one or more tables as required. *B.4.12: ** Do stored procedures have a statement for raising application errors? * Not in MySQL 5.1. The SQL standard `SIGNAL' and `RESIGNAL' statements are implemented in MySQL 5.5. *B.4.13: ** Do stored procedures provide exception handling? * MySQL implements *Note `HANDLER': handler. definitions according to the SQL standard. See *Note declare-handler::, for details. *B.4.14: ** Can MySQL 5.1 stored routines return result sets? * _Stored procedures_ can, but stored functions cannot. If you perform an ordinary *Note `SELECT': select. inside a stored procedure, the result set is returned directly to the client. You need to use the MySQL 4.1 (or above) client/server protocol for this to work. This means that--for instance--in PHP, you need to use the `mysqli' extension rather than the old `mysql' extension. *B.4.15: ** Is `WITH RECOMPILE' supported for stored procedures? * Not in MySQL 5.1. *B.4.16: ** Is there a MySQL equivalent to using `mod_plsql' as a gateway on Apache to talk directly to a stored procedure in the database? * There is no equivalent in MySQL 5.1. *B.4.17: ** Can I pass an array as input to a stored procedure? * Not in MySQL 5.1. *B.4.18: ** Can I pass a cursor as an `IN' parameter to a stored procedure? * In MySQL 5.1, cursors are available inside stored procedures only. *B.4.19: ** Can I return a cursor as an `OUT' parameter from a stored procedure? * In MySQL 5.1, cursors are available inside stored procedures only. However, if you do not open a cursor on a *Note `SELECT': select, the result will be sent directly to the client. You can also `SELECT INTO' variables. See *Note select::. *B.4.20: ** Can I print out a variable's value within a stored routine for debugging purposes? * Yes, you can do this in a _stored procedure_, but not in a stored function. If you perform an ordinary *Note `SELECT': select. inside a stored procedure, the result set is returned directly to the client. You will need to use the MySQL 4.1 (or above) client/server protocol for this to work. This means that--for instance--in PHP, you need to use the `mysqli' extension rather than the old `mysql' extension. *B.4.21: ** Can I commit or roll back transactions inside a stored procedure? * Yes. However, you cannot perform transactional operations within a stored function. *B.4.22: ** Do MySQL 5.1 stored procedures and functions work with replication? * Yes, standard actions carried out in stored procedures and functions are replicated from a master MySQL server to a slave server. There are a few limitations that are described in detail in *Note stored-programs-logging::. *B.4.23: ** Are stored procedures and functions created on a master server replicated to a slave? * Yes, creation of stored procedures and functions carried out through normal DDL statements on a master server are replicated to a slave, so the objects will exist on both servers. `ALTER' and `DROP' statements for stored procedures and functions are also replicated. *B.4.24: ** How are actions that take place inside stored procedures and functions replicated? * MySQL records each DML event that occurs in a stored procedure and replicates those individual actions to a slave server. The actual calls made to execute stored procedures are not replicated. Stored functions that change data are logged as function invocations, not as the DML events that occur inside each function. *B.4.25: ** Are there special security requirements for using stored procedures and functions together with replication? * Yes. Because a slave server has authority to execute any statement read from a master's binary log, special security constraints exist for using stored functions with replication. If replication or binary logging in general (for the purpose of point-in-time recovery) is active, then MySQL DBAs have two security options open to them: 1. Any user wishing to create stored functions must be granted the `SUPER' privilege. 2. Alternatively, a DBA can set the `log_bin_trust_function_creators' system variable to 1, which enables anyone with the standard `CREATE ROUTINE' privilege to create stored functions. *B.4.26: ** What limitations exist for replicating stored procedure and function actions? * Nondeterministic (random) or time-based actions embedded in stored procedures may not replicate properly. By their very nature, randomly produced results are not predictable and cannot be exactly reproduced, and therefore, random actions replicated to a slave will not mirror those performed on a master. Note that declaring stored functions to be `DETERMINISTIC' or setting the `log_bin_trust_function_creators' system variable to 0 will not allow random-valued operations to be invoked. In addition, time-based actions cannot be reproduced on a slave because the timing of such actions in a stored procedure is not reproducible through the binary log used for replication. It records only DML events and does not factor in timing constraints. Finally, nontransactional tables for which errors occur during large DML actions (such as bulk inserts) may experience replication issues in that a master may be partially updated from DML activity, but no updates are done to the slave because of the errors that occurred. A workaround is for a function's DML actions to be carried out with the `IGNORE' keyword so that updates on the master that cause errors are ignored and updates that do not cause errors are replicated to the slave. *B.4.27: ** Do the preceding limitations affect MySQL's ability to do point-in-time recovery? * The same limitations that affect replication do affect point-in-time recovery. *B.4.28: ** What is being done to correct the aforementioned limitations? * As of MySQL 5.1.5, you can choose either statement-based replication or row-based replication. The original replication implementation is based on statement-based binary logging. Row-based binary logging resolves the limitations mentioned earlier. Beginning with MySQL 5.1.8, _mixed_ replication is also available (by starting the server with `--binlog-format=mixed'). This hybrid, `smart' form of replication `knows' whether statement-level replication can safely be used, or row-level replication is required. For additional information, see *Note replication-formats::.  File: manual.info, Node: faqs-triggers, Next: faqs-views, Prev: faqs-stored-procs, Up: faqs B.5 MySQL 5.1 FAQ: Triggers =========================== *Questions* * B.5.1: Where can I find the documentation for MySQL 5.1 triggers? * B.5.2: Is there a discussion forum for MySQL Triggers? * B.5.3: Does MySQL 5.1 have statement-level or row-level triggers? * B.5.4: Are there any default triggers? * B.5.5: How are triggers managed in MySQL? * B.5.6: Is there a way to view all triggers in a given database? * B.5.7: Where are triggers stored? * B.5.8: Can a trigger call a stored procedure? * B.5.9: Can triggers access tables? * B.5.10: Can triggers call an external application through a UDF? * B.5.11: Is it possible for a trigger to update tables on a remote server? * B.5.12: Do triggers work with replication? * B.5.13: How are actions carried out through triggers on a master replicated to a slave? *Questions and Answers* *B.5.1: ** Where can I find the documentation for MySQL 5.1 triggers? * See *Note triggers::. *B.5.2: ** Is there a discussion forum for MySQL Triggers? * Yes. It is available at `http://forums.mysql.com/list.php?99'. *B.5.3: ** Does MySQL 5.1 have statement-level or row-level triggers? * In MySQL 5.1, all triggers are `FOR EACH ROW'--that is, the trigger is activated for each row that is inserted, updated, or deleted. MySQL 5.1 does not support triggers using `FOR EACH STATEMENT'. *B.5.4: ** Are there any default triggers? * Not explicitly. MySQL does have specific special behavior for some *Note `TIMESTAMP': datetime. columns, as well as for columns which are defined using `AUTO_INCREMENT'. *B.5.5: ** How are triggers managed in MySQL? * In MySQL 5.1, triggers can be created using the *Note `CREATE TRIGGER': create-trigger. statement, and dropped using *Note `DROP TRIGGER': drop-trigger. See *Note create-trigger::, and *Note drop-trigger::, for more about these statements. Information about triggers can be obtained by querying the *Note `INFORMATION_SCHEMA.TRIGGERS': triggers-table. table. See *Note triggers-table::. *B.5.6: ** Is there a way to view all triggers in a given database? * Yes. You can obtain a listing of all triggers defined on database `dbname' using a query on the *Note `INFORMATION_SCHEMA.TRIGGERS': triggers-table. table such as the one shown here: SELECT TRIGGER_NAME, EVENT_MANIPULATION, EVENT_OBJECT_TABLE, ACTION_STATEMENT FROM INFORMATION_SCHEMA.TRIGGERS WHERE TRIGGER_SCHEMA='DBNAME'; For more information about this table, see *Note triggers-table::. You can also use the *Note `SHOW TRIGGERS': show-triggers. statement, which is specific to MySQL. See *Note show-triggers::. *B.5.7: ** Where are triggers stored? * Triggers for a table are currently stored in `.TRG' files, with one such file one per table. *B.5.8: ** Can a trigger call a stored procedure? * Yes. *B.5.9: ** Can triggers access tables? * A trigger can access both old and new data in its own table. A trigger can also affect other tables, but it is not permitted to modify a table that is already being used (for reading or writing) by the statement that invoked the function or trigger. *B.5.10: ** Can triggers call an external application through a UDF? * Yes. For example, a trigger could invoke the `sys_exec()' UDF available at MySQL Forge here: `http://forge.mysql.com/projects/project.php?id=211' *B.5.11: ** Is it possible for a trigger to update tables on a remote server? * Yes. A table on a remote server could be updated using the `FEDERATED' storage engine. (See *Note federated-storage-engine::). *B.5.12: ** Do triggers work with replication? * Yes. However, the way in which they work depends whether you are using MySQL's `classic' statement-based replication available in all versions of MySQL, or the row-based replication format introduced in MySQL 5.1. When using statement-based replication, triggers on the slave are executed by statements that are executed on the master (and replicated to the slave). When using row-based replication, triggers are not executed on the slave due to statements that were run on the master and then replicated to the slave. Instead, when using row-based replication, the changes caused by executing the trigger on the master are applied on the slave. For more information, see *Note replication-features-triggers::. *B.5.13: ** How are actions carried out through triggers on a master replicated to a slave? * Again, this depends on whether you are using statement-based or row-based replication. Statement-based replication First, the triggers that exist on a master must be re-created on the slave server. Once this is done, the replication flow works as any other standard DML statement that participates in replication. For example, consider a table `EMP' that has an `AFTER' insert trigger, which exists on a master MySQL server. The same `EMP' table and `AFTER' insert trigger exist on the slave server as well. The replication flow would be: 1. An *Note `INSERT': insert. statement is made to `EMP'. 2. The `AFTER' trigger on `EMP' activates. 3. The *Note `INSERT': insert. statement is written to the binary log. 4. The replication slave picks up the *Note `INSERT': insert. statement to `EMP' and executes it. 5. The `AFTER' trigger on `EMP' that exists on the slave activates. Row-based replication When you use row-based replication, the changes caused by executing the trigger on the master are applied on the slave. However, the triggers themselves are not actually executed on the slave under row-based replication. This is because, if both the master and the slave applied the changes from the master and--in addition--the trigger causing these changes were applied on the slave, the changes would in effect be applied twice on the slave, leading to different data on the master and the slave. In most cases, the outcome is the same for both row-based and statement-based replication. However, if you use different triggers on the master and slave, you cannot use row-based replication. (This is because the row-based format replicates the changes made by triggers executing on the master to the slaves, rather than the statements that caused the triggers to execute, and the corresponding triggers on the slave are not executed.) Instead, any statements causing such triggers to be executed must be replicated using statement-based replication. For more information, see *Note replication-features-triggers::.  File: manual.info, Node: faqs-views, Next: faqs-information-schema, Prev: faqs-triggers, Up: faqs B.6 MySQL 5.1 FAQ: Views ======================== *Questions* * B.6.1: Where can I find documentation covering MySQL Views? * B.6.2: Is there a discussion forum for MySQL Views? * B.6.3: What happens to a view if an underlying table is dropped or renamed? * B.6.4: Does MySQL 5.1 have table snapshots? * B.6.5: Does MySQL 5.1 have materialized views? * B.6.6: Can you insert into views that are based on joins? *Questions and Answers* *B.6.1: ** Where can I find documentation covering MySQL Views? * See *Note views::. *B.6.2: ** Is there a discussion forum for MySQL Views? * Yes. See http://forums.mysql.com/list.php?100 (http://forums.mysql.com/list.php?100) *B.6.3: ** What happens to a view if an underlying table is dropped or renamed? * After a view has been created, it is possible to drop or alter a table or view to which the definition refers. To check a view definition for problems of this kind, use the *Note `CHECK TABLE': check-table. statement. (See *Note check-table::.) *B.6.4: ** Does MySQL 5.1 have table snapshots? * No. *B.6.5: ** Does MySQL 5.1 have materialized views? * No. *B.6.6: ** Can you insert into views that are based on joins? * It is possible, provided that your *Note `INSERT': insert. statement has a column list that makes it clear there is only one table involved. You _cannot_ insert into multiple tables with a single insert on a view.  File: manual.info, Node: faqs-information-schema, Next: faqs-migration, Prev: faqs-views, Up: faqs B.7 MySQL 5.1 FAQ: `INFORMATION_SCHEMA' ======================================= *Questions* * B.7.1: Where can I find documentation for the MySQL `INFORMATION_SCHEMA' database? * B.7.2: Is there a discussion forum for `INFORMATION_SCHEMA'? * B.7.3: Where can I find the ANSI SQL 2003 specification for `INFORMATION_SCHEMA'? * B.7.4: What is the difference between the Oracle Data Dictionary and MySQL's `INFORMATION_SCHEMA'? * B.7.5: Can I add to or otherwise modify the tables found in the `INFORMATION_SCHEMA' database? *Questions and Answers* *B.7.1: ** Where can I find documentation for the MySQL `INFORMATION_SCHEMA' database? * See *Note information-schema:: *B.7.2: ** Is there a discussion forum for `INFORMATION_SCHEMA'? * See http://forums.mysql.com/list.php?101 (http://forums.mysql.com/list.php?101). *B.7.3: ** Where can I find the ANSI SQL 2003 specification for `INFORMATION_SCHEMA'? * Unfortunately, the official specifications are not freely available. (ANSI makes them available for purchase.) However, there are books available--such as `SQL-99 Complete, Really' by Peter Gulutzan and Trudy Pelzer--which give a comprehensive overview of the standard, including `INFORMATION_SCHEMA'. *B.7.4: ** What is the difference between the Oracle Data Dictionary and MySQL's `INFORMATION_SCHEMA'? * Both Oracle and MySQL provide metadata in tables. However, Oracle and MySQL use different table names and column names. MySQL's implementation is more similar to those found in DB2 and SQL Server, which also support `INFORMATION_SCHEMA' as defined in the SQL standard. *B.7.5: ** Can I add to or otherwise modify the tables found in the `INFORMATION_SCHEMA' database? * No. Since applications may rely on a certain standard structure, this should not be modified. For this reason, _we cannot support bugs or other issues which result from modifying `INFORMATION_SCHEMA' tables or data_.  File: manual.info, Node: faqs-migration, Next: faqs-security, Prev: faqs-information-schema, Up: faqs B.8 MySQL 5.1 FAQ: Migration ============================ *Questions* * B.8.1: Where can I find information on how to migrate from MySQL 5.0 to MySQL 5.1? * B.8.2: How has storage engine (table type) support changed in MySQL 5.1 from previous versions? *Questions and Answers* *B.8.1: ** Where can I find information on how to migrate from MySQL 5.0 to MySQL 5.1? * For detailed upgrade information, see *Note upgrading::. Do not skip a major version when upgrading, but rather complete the process in steps, upgrading from one major version to the next in each step. This may seem more complicated, but it will you save time and trouble--if you encounter problems during the upgrade, their origin will be easier to identify, either by you or--if you have a MySQL Enterprise subscription--by MySQL support. *B.8.2: ** How has storage engine (table type) support changed in MySQL 5.1 from previous versions? * Storage engine support has changed as follows: * Support for `ISAM' tables was removed in MySQL 5.0 and you should now use the `MyISAM' storage engine in place of `ISAM'. To convert a table TBLNAME from `ISAM' to `MyISAM', simply issue a statement such as this one: ALTER TABLE TBLNAME ENGINE=MYISAM; * Internal `RAID' for `MyISAM' tables was also removed in MySQL 5.0. This was formerly used to allow large tables in file systems that did not support file sizes greater than 2GB. All modern file systems allow for larger tables; in addition, there are now other solutions such as `MERGE' tables and views. * The *Note `VARCHAR': char. column type now retains trailing spaces in all storage engines. * `MEMORY' tables (formerly known as `HEAP' tables) can also contain *Note `VARCHAR': char. columns.  File: manual.info, Node: faqs-security, Next: faqs-mysql-cluster, Prev: faqs-migration, Up: faqs B.9 MySQL 5.1 FAQ: Security =========================== *Questions* * B.9.1: Where can I find documentation that addresses security issues for MySQL? * B.9.2: Does MySQL 5.1 have native support for SSL? * B.9.3: Is SSL support be built into MySQL binaries, or must I recompile the binary myself to enable it? * B.9.4: Does MySQL 5.1 have built-in authentication against LDAP directories? * B.9.5: Does MySQL 5.1 include support for Roles Based Access Control (RBAC)? *Questions and Answers* *B.9.1: ** Where can I find documentation that addresses security issues for MySQL? * The best place to start is *Note security::. Other portions of the MySQL Documentation which you may find useful with regard to specific security concerns include the following: * *Note security-guidelines::. * *Note security-against-attack::. * *Note resetting-permissions::. * *Note changing-mysql-user::. * *Note udf-security::. * *Note privileges-options::. * *Note load-data-local::. * *Note postinstallation::. * *Note secure-basics::. *B.9.2: ** Does MySQL 5.1 have native support for SSL? * Most 5.1 binaries have support for SSL connections between the client and server. We can't currently build with the new YaSSL library everywhere, as it is still quite new and does not compile on all platforms yet. See *Note secure-connections::. You can also tunnel a connection using SSH, if (for example) the client application doesn't support SSL connections. For an example, see *Note windows-and-ssh::. *B.9.3: ** Is SSL support be built into MySQL binaries, or must I recompile the binary myself to enable it? * Most 5.1 binaries have SSL enabled for client/server connections that are secured, authenticated, or both. However, the YaSSL library currently does not compile on all platforms. See *Note secure-connections::, for a complete listing of supported and unsupported platforms. *B.9.4: ** Does MySQL 5.1 have built-in authentication against LDAP directories? * Not at this time. *B.9.5: ** Does MySQL 5.1 include support for Roles Based Access Control (RBAC)? * Not at this time.  File: manual.info, Node: faqs-mysql-cluster, Next: faqs-cjk, Prev: faqs-security, Up: faqs B.10 MySQL 5.1 FAQ: MySQL Cluster ================================= In the following section, we answer questions that are frequently asked about MySQL Cluster and the *Note `NDBCLUSTER': mysql-cluster. storage engine. *Questions* * B.10.1: Which versions of the MySQL software support Cluster? Do I have to compile from source? * B.10.2: What happened to MySQL Cluster NDB 6.4? * B.10.3: What do `NDB' and `NDBCLUSTER' mean? * B.10.4: What is the difference between using MySQL Cluster _vs_ using MySQL replication? * B.10.5: Do I need to do any special networking to run MySQL Cluster? How do computers in a cluster communicate? * B.10.6: How many computers do I need to run a MySQL Cluster, and why? * B.10.7: What do the different computers do in a MySQL Cluster? * B.10.8: When I run the `SHOW' command in the MySQL Cluster management client, I see a line of output that looks like this: id=2 @10.100.10.32 (Version: 5.1.59, Nodegroup: 0, Master) What is a `master node', and what does it do? How do I configure a node so that it is the master? * B.10.9: With which operating systems can I use Cluster? * B.10.10: What are the hardware requirements for running MySQL Cluster? * B.10.11: How much RAM do I need to use MySQL Cluster? Is it possible to use disk memory at all? * B.10.12: What file systems can I use with MySQL Cluster? What about network file systems or network shares? * B.10.13: Can I run MySQL Cluster nodes inside virtual machines (such as those created by VMWare, Parallels, or Xen)? * B.10.14: I am trying to populate a MySQL Cluster database. The loading process terminates prematurely and I get an error message like this one: ``ERROR 1114: The table 'my_cluster_table' is full'' Why is this happening? * B.10.15: MySQL Cluster uses TCP/IP. Does this mean that I can run it over the Internet, with one or more nodes in remote locations? * B.10.16: Do I have to learn a new programming or query language to use MySQL Cluster? * B.10.17: How do I find out what an error or warning message means when using MySQL Cluster? * B.10.18: Is MySQL Cluster transaction-safe? What isolation levels are supported? * B.10.19: What storage engines are supported by MySQL Cluster? * B.10.20: In the event of a catastrophic failure--say, for instance, the whole city loses power _and_ my UPS fails--would I lose all my data? * B.10.21: Is it possible to use `FULLTEXT' indexes with MySQL Cluster? * B.10.22: Can I run multiple nodes on a single computer? * B.10.23: Can I add data nodes to a MySQL Cluster without restarting it? * B.10.24: Are there any limitations that I should be aware of when using MySQL Cluster? * B.10.25: How do I import an existing MySQL database into a MySQL Cluster? * B.10.26: How do cluster nodes communicate with one another? * B.10.27: What is an _arbitrator_? * B.10.28: What data types are supported by MySQL Cluster? * B.10.29: How do I start and stop MySQL Cluster? * B.10.30: What happens to MySQL Cluster data when the cluster is shut down? * B.10.31: Is it a good idea to have more than one management node for a MySQL Cluster? * B.10.32: Can I mix different kinds of hardware and operating systems in one MySQL Cluster? * B.10.33: Can I run two data nodes on a single host? Two SQL nodes? * B.10.34: Can I use host names with MySQL Cluster? * B.10.35: Does MySQL Cluster support IPv6? * B.10.36: How do I handle MySQL users in a MySQL Cluster having multiple MySQL servers? * B.10.37: How do I continue to send queries in the event that one of the SQL nodes fails? * B.10.38: How do I back up and restore a MySQL Cluster? * B.10.39: What is an `angel process'? *Questions and Answers* *B.10.1: ** Which versions of the MySQL software support Cluster? Do I have to compile from source? * Beginning with MySQL 5.1.24, MySQL Cluster is no longer supported in standard MySQL Server 5.1 releases. Instead, MySQL Cluster is now released as a separate product. Currently, two MySQL Cluster release series are available for production use: * MySQL Cluster NDB 6.3 This series is now Generally Available (GA) for use in production. The latest MySQL Cluster NDB 6.3 sources and binaries can be obtained from `http://dev.mysql.com/downloads/cluster/'. * MySQL Cluster NDB 7.0 This series is now Generally Available (GA) for use in production. The latest MySQL Cluster NDB 7.0 sources can be obtained from `http://dev.mysql.com/downloads/cluster/'. You should use MySQL NDB Cluster NDB 6.3 or 7.0 for any new deployments; if you are already using MySQL 5.1 with clustering support, you should upgrade to one of these MySQL Cluster release series as soon as possible. For an overview of improvements made in MySQL Cluster NDB 6.3 and 7.0, see *Note mysql-cluster-development-5-1-ndb-6-3::, and *Note mysql-cluster-development-5-1-ndb-7-0::, respectively. You can determine whether your MySQL Server has *Note `NDBCLUSTER': mysql-cluster. support using either of the statements `SHOW VARIABLES LIKE 'have_%'' or *Note `SHOW ENGINES': show-engines. *B.10.2: ** What happened to MySQL Cluster NDB 6.4? * Because of the number and impact of new features introduced into MySQL Cluster following the General Availability of MySQL Cluster NDB 6.3, it was decided that the following release series represented a `major' new release series rather than a `minor' one, and should be known as MySQL Cluster 7.0. The earliest development versions of MySQL Cluster NDB 7.0 were originally designated `MySQL Cluster 6.4', and the first four releases in this series were identified as MySQL Cluster NDB 6.4.0 through NDB 6.4.3. MySQL Cluster NDB 7.0.4 is the fifth MySQL Cluster NDB 7.0 release; it is the successor to MySQL Cluster NDB 6.4.3. For more information about MySQL Cluster NDB 7.0, see *Note mysql-cluster-development-5-1-ndb-7-0::, and *Note mysql-cluster-news-7-0::. *B.10.3: ** What do `NDB' and `NDBCLUSTER' mean? * `NDB' stands for `*N*etwork *D*ata*b*ase'. *Note `NDB': mysql-cluster. and *Note `NDBCLUSTER': mysql-cluster. are both names for the storage engine that enables clustering support in MySQL. While our developers prefer *Note `NDB': mysql-cluster, either name is correct; both names appear in our documentation, and either name can be used in the `ENGINE' option of a *Note `CREATE TABLE': create-table. statement for creating a MySQL Cluster table. *B.10.4: ** What is the difference between using MySQL Cluster _vs_ using MySQL replication? * In traditional MySQL replication, a master MySQL server updates one or more slaves. Transactions are committed sequentially, and a slow transaction can cause the slave to lag behind the master. This means that if the master fails, it is possible that the slave might not have recorded the last few transactions. If a transaction-safe engine such as *Note `InnoDB': innodb-storage-engine. is being used, a transaction will either be complete on the slave or not applied at all, but replication does not guarantee that all data on the master and the slave will be consistent at all times. In MySQL Cluster, all data nodes are kept in synchrony, and a transaction committed by any one data node is committed for all data nodes. In the event of a data node failure, all remaining data nodes remain in a consistent state. In short, whereas standard MySQL replication is _asynchronous_, MySQL Cluster is _synchronous_. We have implemented (asynchronous) replication for Cluster in MySQL 5.1 and later. _MySQL Cluster Replication_ (also sometimes known as `geo-replication') includes the capability to replicate both between two MySQL Clusters, and from a MySQL Cluster to a non-Cluster MySQL server. However, we do _not_ plan to backport this functionality to MySQL 5.1. See *Note mysql-cluster-replication::. *B.10.5: ** Do I need to do any special networking to run MySQL Cluster? How do computers in a cluster communicate? * MySQL Cluster is intended to be used in a high-bandwidth environment, with computers connecting using TCP/IP. Its performance depends directly upon the connection speed between the cluster's computers. The minimum connectivity requirements for MySQL Cluster include a typical 100-megabit Ethernet network or the equivalent. We recommend you use gigabit Ethernet whenever available. The faster SCI protocol is also supported, but requires special hardware. See *Note mysql-cluster-interconnects::, for more information about SCI. *B.10.6: ** How many computers do I need to run a MySQL Cluster, and why? * A minimum of three computers is required to run a viable cluster. However, the minimum _recommended_ number of computers in a MySQL Cluster is four: one each to run the management and SQL nodes, and two computers to serve as data nodes. The purpose of the two data nodes is to provide redundancy; the management node must run on a separate machine to guarantee continued arbitration services in the event that one of the data nodes fails. To provide increased throughput and high availability, you should use multiple SQL nodes (MySQL Servers connected to the cluster). It is also possible (although not strictly necessary) to run multiple management servers. *B.10.7: ** What do the different computers do in a MySQL Cluster? * A MySQL Cluster has both a physical and logical organization, with computers being the physical elements. The logical or functional elements of a cluster are referred to as _nodes_, and a computer housing a cluster node is sometimes referred to as a _cluster host_. There are three types of nodes, each corresponding to a specific role within the cluster. These are: * Management node This node provides management services for the cluster as a whole, including startup, shutdown, backups, and configuration data for the other nodes. The management node server is implemented as the application *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd.; the management client used to control MySQL Cluster is *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. See *Note mysql-cluster-programs-ndb-mgmd::, and *Note mysql-cluster-programs-ndb-mgm::, for information about these programs. * Data node This type of node stores and replicates data. Data node functionality is handled by instances of the *Note `NDB': mysql-cluster. data node process *Note `ndbd': mysql-cluster-programs-ndbd. For more information, see *Note mysql-cluster-programs-ndbd::. * SQL node This is simply an instance of MySQL Server (*Note `mysqld': mysqld.) that is built with support for the *Note `NDBCLUSTER': mysql-cluster. storage engine and started with the `--ndb-cluster' option to enable the engine and the `--ndb-connectstring' option to enable it to connect to a MySQL Cluster management server. For more about these options, see *Note mysql-cluster-program-options-mysqld::. *Note*: An _API node_ is any application that makes direct use of Cluster data nodes for data storage and retrieval. An SQL node can thus be considered a type of API node that uses a MySQL Server to provide an SQL interface to the Cluster. You can write such applications (that do not depend on a MySQL Server) using the NDB API, which supplies a direct, object-oriented transaction and scanning interface to MySQL Cluster data; see MySQL Cluster API Overview: The NDB API (http://dev.mysql.com/doc/ndbapi/en/overview-ndb-api.html), for more information. *B.10.8: ** When I run the `SHOW' command in the MySQL Cluster management client, I see a line of output that looks like this: * id=2 @10.100.10.32 (Version: 5.1.59, Nodegroup: 0, Master) * What is a `master node', and what does it do? How do I configure a node so that it is the master? * The simplest answer is, `It's not something you can control, and it's nothing that you need to worry about in any case, unless you're a software engineer writing or analyzing the MySQL Cluster source code'. If you don't find that answer satisfactory, here's a longer and more technical version: A number of mechanisms in MySQL Cluster require distributed coordination among the data nodes. These distributed algorithms and protocols include global checkpointing, DDL (schema) changes, and node restart handling. To make this coordination simpler, the data nodes `elect' one of their number to be a `master'. There is no user-facing mechanism for influencing this selection, which is is completely automatic; the fact that it _is_ automatic is a key part of MySQL Cluster's internal architecture. When a node acts as a master for any of these mechanisms, it is usually the point of coordination for the activity, and the other nodes act as `servants', carrying out their parts of the activity as directed by the master. If the node acting as master fails, then the remaining nodes elect a new master. Tasks in progress that were being coordinated by the old master may either fail or be continued by the new master, depending on the actual mechanism involved. It is possible for some of these different mechanisms and protocols to have different master nodes, but in general the same master is chosen for all of them. The node indicated as the master in the output of `SHOW' in the management client is actually the `DICT' master (see The `DBDICT' Block (http://dev.mysql.com/doc/ndbapi/en/ndb-internals-kernel-blocks-dbdict.html), in the `MySQL Cluster API Developer Guide', for more information), responsible for coordinating DDL and metadata activity. MySQL Cluster is designed in such a way that the choice of master has no discernable effect outside the cluster itself. For example, the current master does not have significantly higher CPU or resource usage than the other data nodes, and failure of the master should not have a significantly different impact on the cluster than the failure of any other data node. *B.10.9: ** With which operating systems can I use Cluster? * MySQL Cluster is supported on most Unix-like operating systems, including Linux, Mac OS X, and Solaris. Beginning with MySQL Cluster NDB 7.1.3, MySQL Cluster is also supported in production on Microsoft Windows operating systems. For more detailed information concerning the level of support which is offered for MySQL Cluster on various operating system versions, operating system distributions, and hardware platforms, please refer to http://www.mysql.com/support/supportedplatforms/cluster.html . *B.10.10: ** What are the hardware requirements for running MySQL Cluster? * MySQL Cluster should run on any platform for which *Note `NDB': mysql-cluster.-enabled binaries are available. For data nodes and API nodes, faster CPUs and more memory are likely to improve performance, and 64-bit CPUs are likely to be more effective than 32-bit processors. There must be sufficient memory on machines used for data nodes to hold each node's share of the database (see _How much RAM do I Need?_ for more information). For a computer which is used only for running the MySQL Cluster management server, the requirements are minimal; a common desktop PC (or the equivalent) is generally sufficient for this task. Nodes can communicate through the standard TCP/IP network and hardware. They can also use the high-speed SCI protocol; however, special networking hardware and software are required to use SCI (see *Note mysql-cluster-interconnects::). *B.10.11: ** How much RAM do I need to use MySQL Cluster? Is it possible to use disk memory at all? * In MySQL 5.1, Cluster is in-memory only. This means that all table data (including indexes) is stored in RAM. Therefore, if your data takes up 1 GB of space and you want to replicate it once in the cluster, you need 2 GB of memory to do so (1 GB per replica). This is in addition to the memory required by the operating system and any applications running on the cluster computers. If a data node's memory usage exceeds what is available in RAM, then the system will attempt to use swap space up to the limit set for `DataMemory'. However, this will at best result in severely degraded performance, and may cause the node to be dropped due to slow response time (missed heartbeats). We do not recommend on relying on disk swapping in a production environment for this reason. In any case, once the `DataMemory' limit is reached, any operations requiring additional memory (such as inserts) will fail. We have implemented disk data storage for MySQL Cluster in MySQL 5.1 and later but we have no plans to add this capability in MySQL 5.1. See *Note mysql-cluster-disk-data::, for more information. You can use the following formula for obtaining a rough estimate of how much RAM is needed for each data node in the cluster: (SizeofDatabase x NumberOfReplicas x 1.1 ) / NumberOfDataNodes To calculate the memory requirements more exactly requires determining, for each table in the cluster database, the storage space required per row (see *Note storage-requirements::, for details), and multiplying this by the number of rows. You must also remember to account for any column indexes as follows: * Each primary key or hash index created for an *Note `NDBCLUSTER': mysql-cluster. table requires 21-25 bytes per record. These indexes use `IndexMemory'. * Each ordered index requires 10 bytes storage per record, using `DataMemory'. * Creating a primary key or unique index also creates an ordered index, unless this index is created with `USING HASH'. In other words: * A primary key or unique index on a Cluster table normally takes up 31 to 35 bytes per record. * However, if the primary key or unique index is created with `USING HASH', then it requires only 21 to 25 bytes per record. Note that creating MySQL Cluster tables with `USING HASH' for all primary keys and unique indexes will generally cause table updates to run more quickly--in some cases by a much as 20 to 30 percent faster than updates on tables where `USING HASH' was not used in creating primary and unique keys. This is due to the fact that less memory is required (because no ordered indexes are created), and that less CPU must be utilized (because fewer indexes must be read and possibly updated). However, it also means that queries that could otherwise use range scans must be satisfied by other means, which can result in slower selects. When calculating Cluster memory requirements, you may find useful the *Note `ndb_size.pl': mysql-cluster-programs-ndb-size-pl. utility which is available in recent MySQL 5.1 releases. This Perl script connects to a current (non-Cluster) MySQL database and creates a report on how much space that database would require if it used the *Note `NDBCLUSTER': mysql-cluster. storage engine. For more information, see *Note mysql-cluster-programs-ndb-size-pl::. It is especially important to keep in mind that _every MySQL Cluster table must have a primary key_. The *Note `NDB': mysql-cluster. storage engine creates a primary key automatically if none is defined; this primary key is created without `USING HASH'. There is no easy way to determine exactly how much memory is being used for storage of Cluster indexes at any given time; however, warnings are written to the Cluster log when 80% of available `DataMemory' or `IndexMemory' is in use, and again when use reaches 85%, 90%, and so on. *B.10.12: ** What file systems can I use with MySQL Cluster? What about network file systems or network shares? * Generally, any file system that is native to the host operating system should work well with MySQL Cluster. If you find that a given file system works particularly well (or not so especially well) with MySQL Cluster, we invite you to discuss your findings in the MySQL Cluster Forums (http://forums.mysql.com/list.php?25). For Windows, we recommend that you use `NTFS' file systems for MySQL Cluster, just as we do for standard MySQL. We do not test MySQL Cluster with `FAT' or `VFAT' file systems. Because of this, we do not recommend their use with MySQL or MySQL Cluster. MySQL Cluster is implemented as a shared-nothing solution; the idea behind this is that the failure of a single piece of hardware should not cause the failure of multiple cluster nodes, or possibly even the failure of the cluster as a whole. For this reason, the use of network shares or network file systems is not supported for MySQL Cluster. This also applies to shared storage devices such as SANs. *B.10.13: ** Can I run MySQL Cluster nodes inside virtual machines (such as those created by VMWare, Parallels, or Xen)? * This is possible but not recommended for a production environment. We have found that running MySQL Cluster processes inside a virtual machine can give rise to issues with timing and disk subsystems that have a strong negative impact on the operation of the cluster. The behavior of the cluster is often unpredictable in these cases. If an issue can be reproduced outside the virtual environment, then we may be able to provide assistance. Otherwise, we cannot support it at this time. *B.10.14: ** I am trying to populate a MySQL Cluster database. The loading process terminates prematurely and I get an error message like this one: ** ``ERROR 1114: The table 'my_cluster_table' is full'' ** Why is this happening? * The cause is very likely to be that your setup does not provide sufficient RAM for all table data and all indexes, _including the primary key required by the *Note `NDB': mysql-cluster. storage engine and automatically created in the event that the table definition does not include the definition of a primary key_. It is also worth noting that all data nodes should have the same amount of RAM, since no data node in a cluster can use more memory than the least amount available to any individual data node. For example, if there are four computers hosting Cluster data nodes, and three of these have 3GB of RAM available to store Cluster data while the remaining data node has only 1GB RAM, then each data node can devote at most 1GB to MySQL Cluster data and indexes. *B.10.15: ** MySQL Cluster uses TCP/IP. Does this mean that I can run it over the Internet, with one or more nodes in remote locations? * It is _very_ unlikely that a cluster would perform reliably under such conditions, as MySQL Cluster was designed and implemented with the assumption that it would be run under conditions guaranteeing dedicated high-speed connectivity such as that found in a LAN setting using 100 Mbps or gigabit Ethernet--preferably the latter. We neither test nor warrant its performance using anything slower than this. Also, it is extremely important to keep in mind that communications between the nodes in a MySQL Cluster are not secure; they are neither encrypted nor safeguarded by any other protective mechanism. The most secure configuration for a cluster is in a private network behind a firewall, with no direct access to any Cluster data or management nodes from outside. (For SQL nodes, you should take the same precautions as you would with any other instance of the MySQL server.) For more information, see *Note mysql-cluster-security::. *B.10.16: ** Do I have to learn a new programming or query language to use MySQL Cluster? * _No_. Although some specialized commands are used to manage and configure the cluster itself, only standard (My)SQL statements are required for the following operations: * Creating, altering, and dropping tables * Inserting, updating, and deleting table data * Creating, changing, and dropping primary and unique indexes Some specialized configuration parameters and files are required to set up a MySQL Cluster--see *Note mysql-cluster-config-file::, for information about these. A few simple commands are used in the MySQL Cluster management client (*Note `ndb_mgm': mysql-cluster-programs-ndb-mgm.) for tasks such as starting and stopping cluster nodes. See *Note mysql-cluster-mgm-client-commands::. *B.10.17: ** How do I find out what an error or warning message means when using MySQL Cluster? * There are two ways in which this can be done: * From within the *Note `mysql': mysql. client, use `SHOW ERRORS' or `SHOW WARNINGS' immediately upon being notified of the error or warning condition. * From a system shell prompt, use *Note `perror --ndb ERROR_CODE': perror. *B.10.18: ** Is MySQL Cluster transaction-safe? What isolation levels are supported? * _Yes_. For tables created with the *Note `NDB': mysql-cluster. storage engine, transactions are supported. Currently, MySQL Cluster supports only the `READ COMMITTED' transaction isolation level. *B.10.19: ** What storage engines are supported by MySQL Cluster? * Clustering with MySQL is supported only by the *Note `NDB': mysql-cluster. storage engine. That is, in order for a table to be shared between nodes in a MySQL Cluster, the table must be created using `ENGINE=NDB' (or the equivalent option `ENGINE=NDBCLUSTER'). It is possible to create tables using other storage engines (such as *Note `MyISAM': myisam-storage-engine. or *Note `InnoDB': innodb-storage-engine.) on a MySQL server being used with a MySQL Cluster, but these non-*Note `NDB': mysql-cluster. tables do _not_ participate in clustering; each such table is strictly local to the individual MySQL server instance on which it is created. *B.10.20: ** In the event of a catastrophic failure--say, for instance, the whole city loses power _and_ my UPS fails--would I lose all my data? * All committed transactions are logged. Therefore, although it is possible that some data could be lost in the event of a catastrophe, this should be quite limited. Data loss can be further reduced by minimizing the number of operations per transaction. (It is not a good idea to perform large numbers of operations per transaction in any case.) *B.10.21: ** Is it possible to use `FULLTEXT' indexes with MySQL Cluster? * `FULLTEXT' indexing is not supported by any storage engine other than *Note `MyISAM': myisam-storage-engine. We are working to add this capability to MySQL Cluster tables in a future release. *B.10.22: ** Can I run multiple nodes on a single computer? * It is possible but not always advisable. One of the chief reasons to run a cluster is to provide redundancy. To obtain the full benefits of this redundancy, each node should reside on a separate machine. If you place multiple nodes on a single machine and that machine fails, you lose all of those nodes. For this reason, if you do run multiple data nodes on a single machine, it is _extremely_ important that they be set up in such a way that the failure of this machine does not cause the loss of all the data nodes in a given node group. Given that MySQL Cluster can be run on commodity hardware loaded with a low-cost (or even no-cost) operating system, the expense of an extra machine or two is well worth it to safeguard mission-critical data. It also worth noting that the requirements for a cluster host running a management node are minimal. This task can be accomplished with a 300 MHz Pentium or equivalent CPU and sufficient RAM for the operating system, plus a small amount of overhead for the *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. and *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. processes. It is acceptable to run multiple cluster data nodes on a single host that has multiple CPUs, cores, or both. Beginning with MySQL Cluster NDB 6.4, there is also a special multi-threaded version of the data node binary intended for use on such systems. For more information, see *Note mysql-cluster-programs-ndbmtd::. It is also possible in some cases to run data nodes and SQL nodes concurrently on the same machine; how well such an arrangement performs is dependent on a number of factors such as number of cores and CPUs as well as the amount of disk and memory available to the data node and SQL node processes, and you must take these factors into account when planning such a configuration. *B.10.23: ** Can I add data nodes to a MySQL Cluster without restarting it? * Beginning with MySQL Cluster NDB 6.4, it is possible to add new data nodes to a running MySQL Cluster without taking it offline. For more information, see *Note mysql-cluster-online-add-node::. For other types of MySQL Cluster nodes, a rolling restart is all that is required (see *Note mysql-cluster-rolling-restart::). In MySQL Cluster NDB 6.3 and earlier, it was not possible to add new data nodes without shutting down and restarting the MySQL Cluster. *B.10.24: ** Are there any limitations that I should be aware of when using MySQL Cluster? * Limitations on *Note `NDB': mysql-cluster. tables in MySQL 5.1 (including MySQL Cluster NDB 6.x) include the following: * Temporary tables are not supported; a *Note `CREATE TEMPORARY TABLE': create-table. statement using `ENGINE=NDB' or `ENGINE=NDBCLUSTER' fails with an error. * The only types of user-defined partitioning supported for *Note `NDBCLUSTER': mysql-cluster. tables are `KEY' and `LINEAR KEY'. (Beginning with MySQL 5.1.12, attempting to create an *Note `NDB': mysql-cluster. table using any other partitioning type fails with an error.) * `FULLTEXT' indexes are not supported. * Index prefixes are not supported. Only complete columns may be indexed. * Spatial indexes are not supported (although spatial columns can be used). See *Note spatial-extensions::. * Prior to MySQL Cluster NDB 6.3.19, the *Note `NDBCLUSTER': mysql-cluster. storage engine did not support partial transactions or partial rollbacks of transactions. Beginning with MySQL Cluster NDB 6.3.19, this limitation has been removed, and the behavior of *Note `NDBCLUSTER': mysql-cluster. is now in line with that of other transactional storage engines (such as *Note `InnoDB': innodb-storage-engine.) that can roll back individual statements. * Prior to MySQL Cluster NDB 7.0.15 and MySQL Cluster NDB 7.1.4, the maximum number of attributes allowed per table was 128; beginning with MySQL Cluster NDB 7.0.15 and MySQL Cluster NDB 7.1.4, this limit is increased to 512. Attribute names cannot be any longer than 31 characters. For each table, the maximum combined length of the table and database names is 122 characters. * The maximum size for a table row is 8 kilobytes, not counting *Note `BLOB': blob. values. There is no set limit for the number of rows per table. Table size limits depend on a number of factors, in particular on the amount of RAM available to each data node. * The *Note `NDBCLUSTER': mysql-cluster. engine does not support foreign key constraints. As with *Note `MyISAM': myisam-storage-engine. tables, if these are specified in a *Note `CREATE TABLE': create-table. or *Note `ALTER TABLE': alter-table. statement, they are ignored. For a complete listing of limitations in MySQL Cluster, see *Note mysql-cluster-limitations::. For information about limitations in MySQL Cluster 5.0 that are lifted in MySQL 5.1, MySQL Cluster NDB 6.x, or MySQL Cluster NDB 7.0, see *Note mysql-cluster-limitations-resolved::. *B.10.25: ** How do I import an existing MySQL database into a MySQL Cluster? * You can import databases into MySQL Cluster much as you would with any other version of MySQL. Other than the limitations mentioned elsewhere in this FAQ, the only other special requirement is that any tables to be included in the cluster must use the *Note `NDB': mysql-cluster. storage engine. This means that the tables must be created with `ENGINE=NDB' or `ENGINE=NDBCLUSTER'. It is also possible to convert existing tables that use other storage engines to *Note `NDBCLUSTER': mysql-cluster. using one or more *Note `ALTER TABLE': alter-table. statement. However, the definition of the table must be compatible with the *Note `NDBCLUSTER': mysql-cluster. storage engine prior to making the conversion. In MySQL 5.1, an additional workaround is also required; see *Note mysql-cluster-limitations::, for details. *B.10.26: ** How do cluster nodes communicate with one another? * Cluster nodes can communicate through any of three different transport mechanisms: TCP/IP, SHM (shared memory), and SCI (Scalable Coherent Interface). Where available, SHM is used by default between nodes residing on the same cluster host; however, this is considered experimental. SCI is a high-speed (1 gigabit per second and higher), high-availability protocol used in building scalable multi-processor systems; it requires special hardware and drivers. See *Note mysql-cluster-interconnects::, for more about using SCI as a transport mechanism for MySQL Cluster. *B.10.27: ** What is an _arbitrator_? * If one or more data nodes in a cluster fail, it is possible that not all cluster data nodes will be able to `see' one another. In fact, it is possible that two sets of data nodes might become isolated from one another in a network partitioning, also known as a `split-brain' scenario. This type of situation is undesirable because each set of data nodes tries to behave as though it is the entire cluster. An arbitrator is required to decide between the competing sets of data nodes. When all data nodes in at least one node group are alive, network partitioning is not an issue, because no single subset of the cluster can form a functional cluster on its own. The real problem arises when no single node group has all its nodes alive, in which case network partitioning (the `split-brain' scenario) becomes possible. Then an arbitrator is required. All cluster nodes recognize the same node as the arbitrator, which is normally the management server; however, it is possible to configure any of the MySQL Servers in the cluster to act as the arbitrator instead. The arbitrator accepts the first set of cluster nodes to contact it, and tells the remaining set to shut down. Arbitrator selection is controlled by the `ArbitrationRank' configuration parameter for MySQL Server and management server nodes. In MySQL Cluster NDB 7.0.7 and later, you can also use the `ArbitrationRank' configuration parameter to control the arbitrator selection process. For more information about these parameters, see *Note mysql-cluster-mgm-definition::. The role of arbitrator does not in and of itself impose any heavy demands upon the host so designated, and thus the arbitrator host does not need to be particularly fast or to have extra memory especially for this purpose. *B.10.28: ** What data types are supported by MySQL Cluster? * MySQL Cluster NDB 6.x and later supports all of the usual MySQL data types, including those associated with MySQL's spatial extensions; however, the *Note `NDB': mysql-cluster. storage engine does not support spatial indexes. (Spatial indexes are supported only by *Note `MyISAM': myisam-storage-engine.; see *Note spatial-extensions::, for more information.) In addition, there are some differences with regard to indexes when used with *Note `NDB': mysql-cluster. tables. *Note*: MySQL Cluster Disk Data tables (that is, tables created with `TABLESPACE ... STORAGE DISK ENGINE=NDB' or `TABLESPACE ... STORAGE DISK ENGINE=NDBCLUSTER') have only fixed-width rows. This means that (for example) each Disk Data table record containing a *Note `VARCHAR(255)': char. column requires space for 255 characters (as required for the character set and collation being used for the table), regardless of the actual number of characters stored therein. See *Note mysql-cluster-limitations::, for more information about these issues. *B.10.29: ** How do I start and stop MySQL Cluster? * It is necessary to start each node in the cluster separately, in the following order: 1. Start the management node, using the *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. command. You must include the `-f' or `--config-file' option to tell the management node where its configuration file can be found. 2. Start each data node with the *Note `ndbd': mysql-cluster-programs-ndbd. command. Each data node must be started with the `-c' or `--connect-string' option so that the data node knows how to connect to the management server. 3. Start each MySQL Server (SQL node) using your preferred startup script, such as *Note `mysqld_safe': mysqld-safe. Each MySQL Server must be started with the `--ndbcluster' and `--ndb-connectstring' options. These options cause mysqld to enable *Note `NDBCLUSTER': mysql-cluster. storage engine support and how to connect to the management server. Each of these commands must be run from a system shell on the machine housing the affected node. (You do not have to be physically present at the machine--a remote login shell can be used for this purpose.) You can verify that the cluster is running by starting the *Note `NDB': mysql-cluster. management client *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. on the machine housing the management node and issuing the `SHOW' or `ALL STATUS' command. To shut down a running cluster, issue the command `SHUTDOWN' in the management client. Alternatively, you may enter the following command in a system shell: shell> ndb_mgm -e "SHUTDOWN" (The quotation marks in this example are optional, since there are no spaces in the command string following the `-e' option; in addition, the `SHUTDOWN' command, like other management client commands, is not case-sensitive.) Either of these commands causes the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm, *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm, and any *Note `ndbd': mysql-cluster-programs-ndbd. processes to terminate gracefully. MySQL servers running as SQL nodes can be stopped using *Note `mysqladmin shutdown': mysqladmin. For more information, see *Note mysql-cluster-mgm-client-commands::, and *Note mysql-cluster-install-shutdown-restart::. *B.10.30: ** What happens to MySQL Cluster data when the cluster is shut down? * The data that was held in memory by the cluster's data nodes is written to disk, and is reloaded into memory the next time that the cluster is started. *B.10.31: ** Is it a good idea to have more than one management node for a MySQL Cluster? * It can be helpful as a fail-safe. Only one management node controls the cluster at any given time, but it is possible to configure one management node as primary, and one or more additional management nodes to take over in the event that the primary management node fails. See *Note mysql-cluster-config-file::, for information on how to configure MySQL Cluster management nodes. *B.10.32: ** Can I mix different kinds of hardware and operating systems in one MySQL Cluster? * Yes, as long as all machines and operating systems have the same `endianness' (all big-endian or all little-endian). We are working to overcome this limitation in a future MySQL Cluster release. It is also possible to use software from different MySQL Cluster releases on different nodes. However, we support this only as part of a rolling upgrade procedure (see *Note mysql-cluster-rolling-restart::). *B.10.33: ** Can I run two data nodes on a single host? Two SQL nodes? * Yes, it is possible to do this. In the case of multiple data nodes, it is advisable (but not required) for each node to use a different data directory. If you want to run multiple SQL nodes on one machine, each instance of *Note `mysqld': mysqld. must use a different TCP/IP port. However, in MySQL 5.1, running more than one cluster node of a given type per machine is generally not encouraged or supported for production use. We also advise against running data nodes and SQL nodes together on the same host, since the *Note `ndbd': mysql-cluster-programs-ndbd. and *Note `mysqld': mysqld. processes may compete for memory. *B.10.34: ** Can I use host names with MySQL Cluster? * Yes, it is possible to use DNS and DHCP for cluster hosts. However, if your application requires `five nines' availability, you should use fixed (numeric) IP addresses, since making communication between Cluster hosts dependent on services such as DNS and DHCP introduces additional potential points of failure. *B.10.35: ** Does MySQL Cluster support IPv6? * Beginning with MySQL Cluster NDB 6.4, IPv6 is supported for connections between SQL nodes (MySQL servers). However, connections between all other types of nodes must use IPv4. In practical terms, this means that you can use IPv6 for replication between MySQL Clusters, but connections between nodes in the same MySQL Cluster must use IPv4. For more information, see *Note mysql-cluster-replication-issues::. *B.10.36: ** How do I handle MySQL users in a MySQL Cluster having multiple MySQL servers? * MySQL user accounts and privileges are _not_ automatically propagated between different MySQL servers accessing the same MySQL Cluster. Therefore, you must make sure that these are copied between the SQL nodes yourself. You can do this manually, or automate the task with scripts. *Warning*: Do not attempt to work around this issue by converting the MySQL system tables to use the *Note `NDBCLUSTER': mysql-cluster. storage engine. Only the *Note `MyISAM': myisam-storage-engine. storage engine is supported for these tables. *B.10.37: ** How do I continue to send queries in the event that one of the SQL nodes fails? * MySQL Cluster does not provide any sort of automatic failover between SQL nodes. Your application must be prepared to handlethe loss of SQL nodes and to fail over between them. *B.10.38: ** How do I back up and restore a MySQL Cluster? * You can use the NDB native backup and restore functionality in the MySQL Cluster management client and the *Note `ndb_restore': mysql-cluster-programs-ndb-restore. program. See *Note mysql-cluster-backup::, and *Note mysql-cluster-programs-ndb-restore::. You can also use the traditional functionality provided for this purpose in *Note `mysqldump': mysqldump. and the MySQL server. See *Note mysqldump::, for more information. *B.10.39: ** What is an `angel process'? * This process monitors and, if necessary, attempts to restart the data node process. If you check the list of active processes on your system after starting *Note `ndbd': mysql-cluster-programs-ndbd, you can see that there are actually 2 processes running by that name, as shown here (we omit the output from *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. and *Note `ndbd': mysql-cluster-programs-ndbd. for brevity): shell> ./ndb_mgmd shell> ps aux | grep ndb me 23002 0.0 0.0 122948 3104 ? Ssl 14:14 0:00 ./ndb_mgmd me 23025 0.0 0.0 5284 820 pts/2 S+ 14:14 0:00 grep ndb shell> ./ndbd -c 127.0.0.1 --initial shell> ps aux | grep ndb me 23002 0.0 0.0 123080 3356 ? Ssl 14:14 0:00 ./ndb_mgmd me 23096 0.0 0.0 35876 2036 ? Ss 14:14 0:00 ./ndbd -c 127.0.0.1 --initial me 23097 1.0 2.4 524116 91096 ? Sl 14:14 0:00 ./ndbd -c 127.0.0.1 --initial me 23168 0.0 0.0 5284 812 pts/2 R+ 14:15 0:00 grep ndb The *Note `ndbd': mysql-cluster-programs-ndbd. process showing 0 memory and CPU usage is the angel process. It actually does use a very small amount of each, of course. It simply checks to see if the main *Note `ndbd': mysql-cluster-programs-ndbd. process (the primary data node process that actually handles the data) is running. If permitted to do so (for example, if the `StopOnError' configuration parameter is set to false--see *Note mysql-cluster-params-ndbd::), the angel process tries to restart the primary data node process.  File: manual.info, Node: faqs-cjk, Next: faqs-connectors-apis, Prev: faqs-mysql-cluster, Up: faqs B.11 MySQL 5.1 FAQ: MySQL Chinese, Japanese, and Korean Character Sets ====================================================================== This set of Frequently Asked Questions derives from the experience of MySQL's Support and Development groups in handling many inquiries about CJK (Chinese-Japanese-Korean) issues. *Questions* * B.11.1: What CJK character sets are available in MySQL? * B.11.2: I have inserted CJK characters into my table. Why does *Note `SELECT': select. display them as `?' characters? * B.11.3: What problems should I be aware of when working with the Big5 Chinese character set? * B.11.4: Why do Japanese character set conversions fail? * B.11.5: What should I do if I want to convert SJIS `81CA' to `cp932'? * B.11.6: How does MySQL represent the Yen (`¥') sign? * B.11.7: Does MySQL plan to make a separate character set where `5C' is the Yen sign, as at least one other major DBMS does? * B.11.8: Of what issues should I be aware when working with Korean character sets in MySQL? * B.11.9: Why do I get `Incorrect string value' error messages? * B.11.10: Why does my GUI front end or browser not display CJK characters correctly in my application using Access, PHP, or another API? * B.11.11: I've upgraded to MySQL 5.1. How can I revert to behavior like that in MySQL 4.0 with regard to character sets? * B.11.12: Why do some `LIKE' and `FULLTEXT' searches with CJK characters fail? * B.11.13: How do I know whether character X is available in all character sets? * B.11.14: Why do CJK strings sort incorrectly in Unicode? (I) * B.11.15: Why do CJK strings sort incorrectly in Unicode? (II) * B.11.16: Why are my supplementary characters rejected by MySQL? * B.11.17: Shouldn't it be `CJKV'? * B.11.18: Does MySQL allow CJK characters to be used in database and table names? * B.11.19: Where can I find translations of the MySQL Manual into Chinese, Japanese, and Korean? * B.11.20: Where can I get help with CJK and related issues in MySQL? *Questions and Answers* *B.11.1: ** What CJK character sets are available in MySQL? * The list of CJK character sets may vary depending on your MySQL version. For example, the `eucjpms' character set was not supported prior to MySQL 5.0.3 (see Changes in MySQL 5.0.3 (http://dev.mysql.com/doc/refman/5.0/en/news-5-0-x.html#news-5-0-3)). However, since the name of the applicable language appears in the `DESCRIPTION' column for every entry in the *Note `INFORMATION_SCHEMA.CHARACTER_SETS': character-sets-table. table, you can obtain a current list of all the non-Unicode CJK character sets using this query: mysql> SELECT CHARACTER_SET_NAME, DESCRIPTION -> FROM INFORMATION_SCHEMA.CHARACTER_SETS -> WHERE DESCRIPTION LIKE '%Chinese%' -> OR DESCRIPTION LIKE '%Japanese%' -> OR DESCRIPTION LIKE '%Korean%' -> ORDER BY CHARACTER_SET_NAME; +--------------------+---------------------------+ | CHARACTER_SET_NAME | DESCRIPTION | +--------------------+---------------------------+ | big5 | Big5 Traditional Chinese | | cp932 | SJIS for Windows Japanese | | eucjpms | UJIS for Windows Japanese | | euckr | EUC-KR Korean | | gb2312 | GB2312 Simplified Chinese | | gbk | GBK Simplified Chinese | | sjis | Shift-JIS Japanese | | ujis | EUC-JP Japanese | +--------------------+---------------------------+ 8 rows in set (0.01 sec) (See *Note character-sets-table::, for more information.) MySQL supports the two common variants of the _GB_ (_Guojia Biaozhun_, or _National Standard_, or _Simplified Chinese_) character sets which are official in the People's Republic of China: `gb2312' and `gbk'. Sometimes people try to insert `gbk' characters into `gb2312', and it works most of the time because `gbk' is a superset of `gb2312'--but eventually they try to insert a rarer Chinese character and it doesn't work. (See Bug#16072 for an example). Here, we try to clarify exactly what characters are legitimate in `gb2312' or `gbk', with reference to the official documents. Please check these references before reporting `gb2312' or `gbk' bugs. * For a complete listing of the `gb2312' characters, ordered according to the `gb2312_chinese_ci' collation: gb2312 (http://www.collation-charts.org/mysql60/by-charset.html#gb2312) * MySQL's `gbk' is in reality `Microsoft code page 936'. This differs from the official `gbk' for characters `A1A4' (middle dot), `A1AA' (em dash), `A6E0-A6F5', and `A8BB-A8C0'. * For a listing of `gbk'/Unicode mappings, see `http://www.unicode.org/Public/MAPPINGS/VENDORS/MICSFT/WINDOWS/CP936.TXT'. * For MySQL's listing of `gbk' characters, see gbk (http://www.collation-charts.org/mysql60/by-charset.html#gbk). *B.11.2: ** I have inserted CJK characters into my table. Why does *Note `SELECT': select. display them as `?' characters? * This problem is usually due to a setting in MySQL that doesn't match the settings for the application program or the operating system. Here are some common steps for correcting these types of issues: * _Be certain of what MySQL version you are using_. Use the statement `SELECT VERSION();' to determine this. * _Make sure that the database is actually using the desired character set_. People often think that the client character set is always the same as either the server character set or the character set used for display purposes. However, both of these are false assumptions. You can make sure by checking the result of `SHOW CREATE TABLE TABLENAME' or--better yet--by using this statement: SELECT character_set_name, collation_name FROM information_schema.columns WHERE table_schema = your_database_name AND table_name = your_table_name AND column_name = your_column_name; * _Determine the hexadecimal value of the character or characters that are not being displayed correctly_. You can obtain this information for a column COLUMN_NAME in the table TABLE_NAME using the following query: SELECT HEX(COLUMN_NAME) FROM TABLE_NAME; `3F' is the encoding for the `?' character; this means that `?' is the character actually stored in the column. This most often happens because of a problem converting a particular character from your client character set to the target character set. * _Make sure that a round trip possible--that is, when you select LITERAL (or _INTRODUCER HEXADECIMAL-VALUE), you obtain LITERAL as a result_. For example, the Japanese _Katakana_ character _Pe_ (`ペ'') exists in all CJK character sets, and has the code point value (hexadecimal coding) `0x30da'. To test a round trip for this character, use this query: SELECT 'ペ' AS `ペ`; /* or SELECT _ucs2 0x30da; */ If the result is not also `ペ', then the round trip has failed. For bug reports regarding such failures, we might ask you to follow up with `SELECT HEX('ペ');'. Then we can determine whether the client encoding is correct. * _Make sure that the problem is not with the browser or other application, rather than with MySQL_. Use the *Note `mysql': mysql. client program (on Windows: *Note `mysql.exe': mysql.) to accomplish this task. If *Note `mysql': mysql. displays correctly but your application doesn't, then your problem is probably due to system settings. To find out what your settings are, use the *Note `SHOW VARIABLES': show-variables. statement, whose output should resemble what is shown here: mysql> SHOW VARIABLES LIKE 'char%'; +--------------------------+----------------------------------------+ | Variable_name | Value | +--------------------------+----------------------------------------+ | character_set_client | utf8 | | character_set_connection | utf8 | | character_set_database | latin1 | | character_set_filesystem | binary | | character_set_results | utf8 | | character_set_server | latin1 | | character_set_system | utf8 | | character_sets_dir | /usr/local/mysql/share/mysql/charsets/ | +--------------------------+----------------------------------------+ 8 rows in set (0.03 sec) These are typical character-set settings for an international-oriented client (notice the use of `utf8' Unicode) connected to a server in the West (`latin1' is a West Europe character set and a default for MySQL). Although Unicode (usually the `utf8' variant on Unix, and the `ucs2' variant on Windows) is preferable to Latin, it is often not what your operating system utilities support best. Many Windows users find that a Microsoft character set, such as `cp932' for Japanese Windows, is suitable. If you cannot control the server settings, and you have no idea what your underlying computer is, then try changing to a common character set for the country that you're in (`euckr' = Korea; `gb2312' or `gbk' = People's Republic of China; `big5' = Taiwan; `sjis', `ujis', `cp932', or `eucjpms' = Japan; `ucs2' or `utf8' = anywhere). Usually it is necessary to change only the client and connection and results settings. There is a simple statement which changes all three at once: `SET NAMES'. For example: SET NAMES 'big5'; Once the setting is correct, you can make it permanent by editing `my.cnf' or `my.ini'. For example you might add lines looking like these: [mysqld] character-set-server=big5 [client] default-character-set=big5 It is also possible that there are issues with the API configuration setting being used in your application; see `Why does my GUI front end or browser not display CJK characters correctly...?' for more information. *B.11.3: ** What problems should I be aware of when working with the Big5 Chinese character set? * MySQL supports the Big5 character set which is common in Hong Kong and Taiwan (Republic of China). MySQL's `big5' is in reality Microsoft code page 950, which is very similar to the original `big5' character set. We changed to this character set starting with MySQL version 4.1.16 / 5.0.16 (as a result of Bug#12476). For example, the following statements work in current versions of MySQL, but not in old versions: mysql> CREATE TABLE big5 (BIG5 CHAR(1) CHARACTER SET BIG5); Query OK, 0 rows affected (0.13 sec) mysql> INSERT INTO big5 VALUES (0xf9dc); Query OK, 1 row affected (0.00 sec) mysql> SELECT * FROM big5; +------+ | big5 | +------+ | 嫺 | +------+ 1 row in set (0.02 sec) A feature request for adding `HKSCS' extensions has been filed. People who need this extension may find the suggested patch for Bug#13577 to be of interest. *B.11.4: ** Why do Japanese character set conversions fail? * MySQL supports the `sjis', `ujis', `cp932', and `eucjpms' character sets, as well as Unicode. A common need is to convert between character sets. For example, there might be a Unix server (typically with `sjis' or `ujis') and a Windows client (typically with `cp932'). In the following conversion table, the `ucs2' column represents the source, and the `sjis', `cp932', `ujis', and `eucjpms' columns represent the destinations--that is, the last 4 columns provide the hexadecimal result when we use `CONVERT(ucs2)' or we assign a `ucs2' column containing the value to an `sjis', `cp932', `ujis', or `eucjpms' column. Character Name ucs2 sjis cp932 ujis eucjpms BROKEN BAR 00A6 3F 3F 8FA2C3 3F FULLWIDTH BROKEN BAR FFE4 3F FA55 3F 8FA2 YEN SIGN 00A5 3F 3F 20 3F FULLWIDTH YEN SIGN FFE5 818F 818F A1EF 3F TILDE 007E 7E 7E 7E 7E OVERLINE 203E 3F 3F 20 3F HORIZONTAL BAR 2015 815C 815C A1BD A1BD EM DASH 2014 3F 3F 3F 3F REVERSE SOLIDUS 005C 815F 5C 5C 5C FULLWIDTH "" FF3C 3F 815F 3F A1C0 WAVE DASH 301C 8160 3F A1C1 3F FULLWIDTH TILDE FF5E 3F 8160 3F A1C1 DOUBLE VERTICAL LINE 2016 8161 3F A1C2 3F PARALLEL TO 2225 3F 8161 3F A1C2 MINUS SIGN 2212 817C 3F A1DD 3F FULLWIDTH HYPHEN-MINUS FF0D 3F 817C 3F A1DD CENT SIGN 00A2 8191 3F A1F1 3F FULLWIDTH CENT SIGN FFE0 3F 8191 3F A1F1 POUND SIGN 00A3 8192 3F A1F2 3F FULLWIDTH POUND SIGN FFE1 3F 8192 3F A1F2 NOT SIGN 00AC 81CA 3F A2CC 3F FULLWIDTH NOT SIGN FFE2 3F 81CA 3F A2CC Now consider the following portion of the table. ucs2 sjis cp932 NOT SIGN 00AC 81CA 3F FULLWIDTH NOT SIGN FFE2 3F 81CA This means that MySQL converts the `NOT SIGN' (Unicode `U+00AC') to `sjis' code point `0x81CA' and to `cp932' code point `3F'. (`3F' is the question mark (`?')--this is what is always used when the conversion cannot be performed. *B.11.5: ** What should I do if I want to convert SJIS `81CA' to `cp932'? * Our answer is: `?'. There are serious complaints about this: many people would prefer a `loose' conversion, so that `81CA (NOT SIGN)' in `sjis' becomes `81CA (FULLWIDTH NOT SIGN)' in `cp932'. We are considering a change to this behavior. *B.11.6: ** How does MySQL represent the Yen (`¥') sign? * A problem arises because some versions of Japanese character sets (both `sjis' and `euc') treat `5C' as a _reverse solidus_ (`\'--also known as a backslash), and others treat it as a yen sign (`¥'). MySQL follows only one version of the JIS (Japanese Industrial Standards) standard description. In MySQL, _`5C' is always the reverse solidus (`\')_. *B.11.7: ** Does MySQL plan to make a separate character set where `5C' is the Yen sign, as at least one other major DBMS does? * This is one possible solution to the Yen sign issue; however, this will not happen in MySQL 5.1 or 6.0. *B.11.8: ** Of what issues should I be aware when working with Korean character sets in MySQL? * In theory, while there have been several versions of the `euckr' (_Extended Unix Code Korea_) character set, only one problem has been noted. We use the `ASCII' variant of EUC-KR, in which the code point `0x5c' is REVERSE SOLIDUS, that is `\', instead of the `KS-Roman' variant of EUC-KR, in which the code point `0x5c' is `WON SIGN'(`₩'). This means that you cannot convert Unicode `U+20A9' to `euckr': mysql> SELECT -> CONVERT('₩' USING euckr) AS euckr, -> HEX(CONVERT('₩' USING euckr)) AS hexeuckr; +-------+----------+ | euckr | hexeuckr | +-------+----------+ | ? | 3F | +-------+----------+ 1 row in set (0.00 sec) MySQL's graphic Korean chart is here: euckr (http://www.collation-charts.org/mysql60/by-charset.html#euckr). *B.11.9: ** Why do I get `Incorrect string value' error messages? * For illustration, we'll create a table with one Unicode (`ucs2') column and one Chinese (`gb2312') column. mysql> CREATE TABLE ch -> (ucs2 CHAR(3) CHARACTER SET ucs2, -> gb2312 CHAR(3) CHARACTER SET gb2312); Query OK, 0 rows affected (0.05 sec) We'll try to place the rare character `汌' in both columns. mysql> INSERT INTO ch VALUES ('A汌B','A汌B'); Query OK, 1 row affected, 1 warning (0.00 sec) Ah, there is a warning. Use the following statement to see what it is: mysql> SHOW WARNINGS\G *************************** 1. row *************************** Level: Warning Code: 1366 Message: Incorrect string value: '\xE6\xB1\x8CB' for column 'gb2312' at row 1 1 row in set (0.00 sec) So it is a warning about the `gb2312' column only. mysql> SELECT ucs2,HEX(ucs2),gb2312,HEX(gb2312) FROM ch; +-------+--------------+--------+-------------+ | ucs2 | HEX(ucs2) | gb2312 | HEX(gb2312) | +-------+--------------+--------+-------------+ | A汌B | 00416C4C0042 | A?B | 413F42 | +-------+--------------+--------+-------------+ 1 row in set (0.00 sec) Several things need explanation here: 1. The fact that it is a `warning' rather than an `error' is characteristic of MySQL. We like to try to do what we can, to get the best fit, rather than give up. 2. The `汌' character is not in the `gb2312' character set. We described that problem earlier. 3. If you are using an old version of MySQL, you will probably see a different message. 4. With `sql_mode=TRADITIONAL', there would be an error message, rather than a warning. *B.11.10: ** Why does my GUI front end or browser not display CJK characters correctly in my application using Access, PHP, or another API? * Obtain a direct connection to the server using the *Note `mysql': mysql. client (Windows: *Note `mysql.exe': mysql.), and try the same query there. If *Note `mysql': mysql. responds correctly, then the trouble may be that your application interface requires initialization. Use *Note `mysql': mysql. to tell you what character set or sets it uses with the statement `SHOW VARIABLES LIKE 'char%';'. If you are using Access, then you are most likely connecting with MyODBC. In this case, you should check *Note connector-odbc-configuration::. If, for instance, you use `big5', you would enter `SET NAMES 'big5''. (Note that no `;' is required in this case). If you are using ASP, you might need to add `SET NAMES' in the code. Here is an example that has worked in the past: <% Session.CodePage=0 Dim strConnection Dim Conn strConnection="driver={MySQL ODBC 3.51 Driver};server=SERVER;uid=USERNAME;" \ & "pwd=PASSWORD;database=DATABASE;stmt=SET NAMES 'big5';" Set Conn = Server.CreateObject("ADODB.Connection") Conn.Open strConnection %> In much the same way, if you are using any character set other than `latin1' with Connector/NET, then you must specify the character set in the connection string. See *Note connector-net-programming-connecting::, for more information. If you are using PHP, try this: In this case, we used `SET NAMES' to change `character_set_client' and `character_set_connection' and `character_set_results'. We encourage the use of the newer `mysqli' extension, rather than `mysql'. Using `mysqli', the previous example could be rewritten as shown here: query("SET NAMES 'utf8'"); ?> Another issue often encountered in PHP applications has to do with assumptions made by the browser. Sometimes adding or changing a `' tag suffices to correct the problem: for example, to insure that the user agent interprets page content as `UTF-8', you should include `' in the `' of the HTML page. If you are using Connector/J, see *Note connector-j-reference-charsets::. *B.11.11: ** I've upgraded to MySQL 5.1. How can I revert to behavior like that in MySQL 4.0 with regard to character sets? * In MySQL Version 4.0, there was a single `global' character set for both server and client, and the decision as to which character to use was made by the server administrator. This changed starting with MySQL Version 4.1. What happens now is a `handshake', as described in *Note charset-connection::: When a client connects, it sends to the server the name of the character set that it wants to use. The server uses the name to set the `character_set_client', `character_set_results', and `character_set_connection' system variables. In effect, the server performs a `SET NAMES' operation using the character set name. The effect of this is that you cannot control the client character set by starting *Note `mysqld': mysqld. with `--character-set-server=utf8'. However, some of our Asian customers have said that they prefer the MySQL 4.0 behavior. To make it possible to retain this behavior, we added a *Note `mysqld': mysqld. switch, `--character-set-client-handshake', which can be turned off with `--skip-character-set-client-handshake'. If you start *Note `mysqld': mysqld. with `--skip-character-set-client-handshake', then, when a client connects, it sends to the server the name of the character set that it wants to use--however, _the server ignores this request from the client_. By way of example, suppose that your favorite server character set is `latin1' (unlikely in a CJK area, but this is the default value). Suppose further that the client uses `utf8' because this is what the client's operating system supports. Now, start the server with `latin1' as its default character set: mysqld --character-set-server=latin1 And then start the client with the default character set `utf8': mysql --default-character-set=utf8 The current settings can be seen by viewing the output of *Note `SHOW VARIABLES': show-variables.: mysql> SHOW VARIABLES LIKE 'char%'; +--------------------------+----------------------------------------+ | Variable_name | Value | +--------------------------+----------------------------------------+ | character_set_client | utf8 | | character_set_connection | utf8 | | character_set_database | latin1 | | character_set_filesystem | binary | | character_set_results | utf8 | | character_set_server | latin1 | | character_set_system | utf8 | | character_sets_dir | /usr/local/mysql/share/mysql/charsets/ | +--------------------------+----------------------------------------+ 8 rows in set (0.01 sec) Now stop the client, and then stop the server using *Note `mysqladmin': mysqladmin. Then start the server again, but this time tell it to skip the handshake like so: mysqld --character-set-server=utf8 --skip-character-set-client-handshake Start the client with `utf8' once again as the default character set, then display the current settings: mysql> SHOW VARIABLES LIKE 'char%'; +--------------------------+----------------------------------------+ | Variable_name | Value | +--------------------------+----------------------------------------+ | character_set_client | latin1 | | character_set_connection | latin1 | | character_set_database | latin1 | | character_set_filesystem | binary | | character_set_results | latin1 | | character_set_server | latin1 | | character_set_system | utf8 | | character_sets_dir | /usr/local/mysql/share/mysql/charsets/ | +--------------------------+----------------------------------------+ 8 rows in set (0.01 sec) As you can see by comparing the differing results from *Note `SHOW VARIABLES': show-variables, the server ignores the client's initial settings if the `--skip-character-set-client-handshake' is used. *B.11.12: ** Why do some `LIKE' and `FULLTEXT' searches with CJK characters fail? * There is a very simple problem with `LIKE' searches on *Note `BINARY': binary-varbinary. and *Note `BLOB': blob. columns: we need to know the end of a character. With multi-byte character sets, different characters might have different octet lengths. For example, in `utf8', `A' requires one byte but `ペ' requires three bytes, as shown here: +-------------------------+---------------------------+ | OCTET_LENGTH(_utf8 'A') | OCTET_LENGTH(_utf8 'ペ') | +-------------------------+---------------------------+ | 1 | 3 | +-------------------------+---------------------------+ 1 row in set (0.00 sec) If we don't know where the first character ends, then we don't know where the second character begins, in which case even very simple searches such as `LIKE '_A%'' fail. The solution is to use a regular CJK character set in the first place, or to convert to a CJK character set before comparing. This is one reason why MySQL cannot allow encodings of nonexistent characters. If it is not strict about rejecting bad input, then it has no way of knowing where characters end. For `FULLTEXT' searches, we need to know where words begin and end. With Western languages, this is rarely a problem because most (if not all) of these use an easy-to-identify word boundary--the space character. However, this is not usually the case with Asian writing. We could use arbitrary halfway measures, like assuming that all Han characters represent words, or (for Japanese) depending on changes from Katakana to Hiragana due to grammatical endings. However, the only sure solution requires a comprehensive word list, which means that we would have to include a dictionary in the server for each Asian language supported. This is simply not feasible. *B.11.13: ** How do I know whether character X is available in all character sets? * The majority of simplified Chinese and basic nonhalfwidth Japanese _Kana_ characters appear in all CJK character sets. This stored procedure accepts a `UCS-2' Unicode character, converts it to all other character sets, and displays the results in hexadecimal. DELIMITER // CREATE PROCEDURE p_convert(ucs2_char CHAR(1) CHARACTER SET ucs2) BEGIN CREATE TABLE tj (ucs2 CHAR(1) character set ucs2, utf8 CHAR(1) character set utf8, big5 CHAR(1) character set big5, cp932 CHAR(1) character set cp932, eucjpms CHAR(1) character set eucjpms, euckr CHAR(1) character set euckr, gb2312 CHAR(1) character set gb2312, gbk CHAR(1) character set gbk, sjis CHAR(1) character set sjis, ujis CHAR(1) character set ujis); INSERT INTO tj (ucs2) VALUES (ucs2_char); UPDATE tj SET utf8=ucs2, big5=ucs2, cp932=ucs2, eucjpms=ucs2, euckr=ucs2, gb2312=ucs2, gbk=ucs2, sjis=ucs2, ujis=ucs2; /* If there is a conversion problem, UPDATE will produce a warning. */ SELECT hex(ucs2) AS ucs2, hex(utf8) AS utf8, hex(big5) AS big5, hex(cp932) AS cp932, hex(eucjpms) AS eucjpms, hex(euckr) AS euckr, hex(gb2312) AS gb2312, hex(gbk) AS gbk, hex(sjis) AS sjis, hex(ujis) AS ujis FROM tj; DROP TABLE tj; END// The input can be any single `ucs2' character, or it can be the code point value (hexadecimal representation) of that character. For example, from Unicode's list of `ucs2' encodings and names (`http://www.unicode.org/Public/UNIDATA/UnicodeData.txt'), we know that the _Katakana_ character _Pe_ appears in all CJK character sets, and that its code point value is `0x30da'. If we use this value as the argument to `p_convert()', the result is as shown here: mysql> CALL p_convert(0x30da)// +------+--------+------+-------+---------+-------+--------+------+------+------+ | ucs2 | utf8 | big5 | cp932 | eucjpms | euckr | gb2312 | gbk | sjis | ujis | +------+--------+------+-------+---------+-------+--------+------+------+------+ | 30DA | E3839A | C772 | 8379 | A5DA | ABDA | A5DA | A5DA | 8379 | A5DA | +------+--------+------+-------+---------+-------+--------+------+------+------+ 1 row in set (0.04 sec) Since none of the column values is `3F'--that is, the question mark character (`?')--we know that every conversion worked. *B.11.14: ** Why do CJK strings sort incorrectly in Unicode? (I) * Sometimes people observe that the result of a `utf8_unicode_ci' or `ucs2_unicode_ci' search, or of an `ORDER BY' sort is not what they think a native would expect. Although we never rule out the possibility that there is a bug, we have found in the past that many people do not read correctly the standard table of weights for the Unicode Collation Algorithm. MySQL uses the table found at `http://www.unicode.org/Public/UCA/4.0.0/allkeys-4.0.0.txt'. This is not the first table you will find by navigating from the `unicode.org' home page, because MySQL uses the older 4.0.0 `allkeys' table, rather than the more recent 4.1.0 table. (The newer `'520'' collations in MySQL 5.6 use the 5.2 `allkeys' table.) This is because we are very wary about changing ordering which affects indexes, lest we bring about situations such as that reported in Bug #16526, illustrated as follows: mysql< CREATE TABLE tj (s1 CHAR(1) CHARACTER SET utf8 COLLATE utf8_unicode_ci); Query OK, 0 rows affected (0.05 sec) mysql> INSERT INTO tj VALUES ('が'),('か'); Query OK, 2 rows affected (0.00 sec) Records: 2 Duplicates: 0 Warnings: 0 mysql> SELECT * FROM tj WHERE s1 = 'か'; +------+ | s1 | +------+ | が | | か | +------+ 2 rows in set (0.00 sec) The character in the first result row is not the one that we searched for. Why did MySQL retrieve it? First we look for the Unicode code point value, which is possible by reading the hexadecimal number for the `ucs2' version of the characters: mysql> SELECT s1, HEX(CONVERT(s1 USING ucs2)) FROM tj; +------+-----------------------------+ | s1 | HEX(CONVERT(s1 USING ucs2)) | +------+-----------------------------+ | が | 304C | | か | 304B | +------+-----------------------------+ 2 rows in set (0.03 sec) Now we search for `304B' and `304C' in the `4.0.0 allkeys' table, and find these lines: 304B ; [.1E57.0020.000E.304B] # HIRAGANA LETTER KA 304C ; [.1E57.0020.000E.304B][.0000.0140.0002.3099] # HIRAGANA LETTER GA; QQCM The official Unicode names (following the `#' mark) tell us the Japanese syllabary (Hiragana), the informal classification (letter, digit, or punctuation mark), and the Western identifier (`KA' or `GA', which happen to be voiced and unvoiced components of the same letter pair). More importantly, the _primary weight_ (the first hexadecimal number inside the square brackets) is `1E57' on both lines. For comparisons in both searching and sorting, MySQL pays attention to the primary weight only, ignoring all the other numbers. This means that we are sorting `が' and `か' correctly according to the Unicode specification. If we wanted to distinguish them, we'd have to use a non-UCA (Unicode Collation Algorithm) collation (`utf8_bin' or `utf8_general_ci'), or to compare the `HEX()' values, or use `ORDER BY CONVERT(s1 USING sjis)'. Being correct `according to Unicode' isn't enough, of course: the person who submitted the bug was equally correct. We plan to add another collation for Japanese according to the JIS X 4061 standard, in which voiced/unvoiced letter pairs like `KA'/`GA' are distinguishable for ordering purposes. *B.11.15: ** Why do CJK strings sort incorrectly in Unicode? (II) * If you are using Unicode (`ucs2' or `utf8'), and you know what the Unicode sort order is (see *Note faqs-cjk::), but MySQL still seems to sort your table incorrectly, then you should first verify the table character set: mysql> SHOW CREATE TABLE t\G ******************** 1. row ****************** Table: t Create Table: CREATE TABLE `t` ( `s1` char(1) CHARACTER SET ucs2 DEFAULT NULL ) ENGINE=MyISAM DEFAULT CHARSET=latin1 1 row in set (0.00 sec) Since the character set appears to be correct, let's see what information the *Note `INFORMATION_SCHEMA.COLUMNS': columns-table. table can provide about this column: mysql> SELECT COLUMN_NAME, CHARACTER_SET_NAME, COLLATION_NAME -> FROM INFORMATION_SCHEMA.COLUMNS -> WHERE COLUMN_NAME = 's1' -> AND TABLE_NAME = 't'; +-------------+--------------------+-----------------+ | COLUMN_NAME | CHARACTER_SET_NAME | COLLATION_NAME | +-------------+--------------------+-----------------+ | s1 | ucs2 | ucs2_general_ci | +-------------+--------------------+-----------------+ 1 row in set (0.01 sec) (See *Note columns-table::, for more information.) You can see that the collation is `ucs2_general_ci' instead of `ucs2_unicode_ci'. The reason why this is so can be found using `SHOW CHARSET', as shown here: mysql> SHOW CHARSET LIKE 'ucs2%'; +---------+---------------+-------------------+--------+ | Charset | Description | Default collation | Maxlen | +---------+---------------+-------------------+--------+ | ucs2 | UCS-2 Unicode | ucs2_general_ci | 2 | +---------+---------------+-------------------+--------+ 1 row in set (0.00 sec) For `ucs2' and `utf8', the default collation is `general'. To specify a Unicode collation, use `COLLATE ucs2_unicode_ci'. *B.11.16: ** Why are my supplementary characters rejected by MySQL? * Before MySQL 5.5.3, MySQL does not support supplementary characters--that is, characters which need more than 3 bytes--for `UTF-8'. We support only what Unicode calls the _Basic Multilingual Plane / Plane 0_. Only a few very rare Han characters are supplementary; support for them is uncommon. This has led to reports such as that found in Bug#12600, which we rejected as `not a bug'. With `utf8', we must truncate an input string when we encounter bytes that we don't understand. Otherwise, we wouldn't know how long the bad multi-byte character is. One possible workaround is to use `ucs2' instead of `utf8', in which case the `bad' characters are changed to question marks; however, no truncation takes place. You can also change the data type to *Note `BLOB': blob. or *Note `BINARY': binary-varbinary, which perform no validity checking. As of MySQL 5.5.3, Unicode support is extended to include supplementary characters by means of additional Unicode character sets: `utf16', `utf32', and 4-byte `utf8mb4'. These character sets support supplementary Unicode characters outside the Basic Multilingual Plane (BMP). *B.11.17: ** Shouldn't it be `CJKV'? * No. The term `CJKV' (_Chinese Japanese Korean Vietnamese_) refers to Vietnamese character sets which contain Han (originally Chinese) characters. MySQL has no plan to support the old Vietnamese script using Han characters. MySQL does of course support the modern Vietnamese script with Western characters. As of MySQL 5.6, there are Vietnamese collations for Unicode character sets, as described in *Note charset-unicode-sets::. *B.11.18: ** Does MySQL allow CJK characters to be used in database and table names? * This issue is fixed in MySQL 5.1, by automatically rewriting the names of the corresponding directories and files. For example, if you create a database named `楮' on a server whose operating system does not support CJK in directory names, MySQL creates a directory named `@0w@00a5@00ae'. which is just a fancy way of encoding `E6A5AE'--that is, the Unicode hexadecimal representation for the `楮' character. However, if you run a *Note `SHOW DATABASES': show-databases. statement, you can see that the database is listed as `楮'. *B.11.19: ** Where can I find translations of the MySQL Manual into Chinese, Japanese, and Korean? * A Simplified Chinese version of the Manual, current for MySQL 5.1.12, can be found at `http://dev.mysql.com/doc/'. The Japanese translation of the MySQL 4.1 manual can be downloaded from `http://dev.mysql.com/doc/'. *B.11.20: ** Where can I get help with CJK and related issues in MySQL? * The following resources are available: * A listing of MySQL user groups can be found at `http://dev.mysql.com/user-groups/'. * View feature requests relating to character set issues at `http://tinyurl.com/y6xcuf'. * Visit the MySQL Collation Unicode Forum. We are also in the process of adding foreign-language forums at `http://forums.mysql.com/'.  File: manual.info, Node: faqs-connectors-apis, Next: faqs-replication, Prev: faqs-cjk, Up: faqs B.12 MySQL 5.1 FAQ: Connectors & APIs ===================================== For common questions, issues, and answers relating to the MySQL Connectors and other APIs, see the following areas of the Manual: * *Note c-api-problems:: * *Note apis-php-problems:: * *Note connector-odbc-usagenotes:: * *Note connector-net-programming:: * *Note connector-j-usagenotes:: * *Note connector-mxj-usagenotes::  File: manual.info, Node: faqs-replication, Next: faqs-mysql-drbd-heartbeat, Prev: faqs-connectors-apis, Up: faqs B.13 MySQL 5.1 FAQ: Replication =============================== For answers to common queries and question regarding Replication within MySQL, see *Note replication-faq::.  File: manual.info, Node: faqs-mysql-drbd-heartbeat, Prev: faqs-replication, Up: faqs B.14 MySQL 5.1 FAQ: MySQL, DRBD, and Heartbeat ============================================== * Menu: * faqs-drbd:: Distributed Replicated Block Device (DRBD) * drbd-linux-heartbeat:: Linux Heartbeat * drbd-architecture:: DRBD Architecture * drbd-mysql-replication-scale:: DRBD and MySQL Replication * drbd-file-systems:: DRBD and File Systems * drbd-lvm:: DRBD and LVM * drbd-virtualization:: DRBD and Virtualization * drbd-security:: DRBD and Security * drbd-system-requirements:: DRBD and System Requirements * drbd-support-consulting:: DRBD and Support and Consulting  File: manual.info, Node: faqs-drbd, Next: drbd-linux-heartbeat, Prev: faqs-mysql-drbd-heartbeat, Up: faqs-mysql-drbd-heartbeat B.14.1 Distributed Replicated Block Device (DRBD) ------------------------------------------------- In the following section, we provide answers to questions that are most frequently asked about Distributed Replicated Block Device (DRBD). *Questions* * B.14.1.1: What is DRBD? * B.14.1.2: What are `Block Devices'? * B.14.1.3: How is DRBD licensed? * B.14.1.4: Where can I download DRBD? * B.14.1.5: If I find a bug in DRBD, to whom do I submit the issue? * B.14.1.6: Where can I get more technical and business information concerning MySQL and DRBD? *Questions and Answers* *B.14.1.1: ** What is DRBD? * DRBD is an acronym for Distributed Replicated Block Device. DRBD is an open source Linux kernel block device which leverages synchronous replication to achieve a consistent view of data between two systems, typically an Active and Passive system. DRBD currently supports all the major flavors of Linux and comes bundled in several major Linux distributions. The DRBD project is maintained by LINBIT (http://www.drbd.org/). *B.14.1.2: ** What are `Block Devices'? * A _block device_ is the type of device used to represent storage in the Linux Kernel. All physical disk devices present a block device interface. Additionally, virtual disk systems like LVM or DRBD present a block device interface. In this way, the file system or other software that might want to access a disk device can be used with any number of real or virtual devices without having to know anything about their underlying implementation details. *B.14.1.3: ** How is DRBD licensed? * DRBD is licensed under the GPL. *B.14.1.4: ** Where can I download DRBD? * Please see `http://www.drbd.org/download/packages/'. *B.14.1.5: ** If I find a bug in DRBD, to whom do I submit the issue? * Bug reports should be submitted to the DRBD mailing list. Please see `http://lists.linbit.com/'. *B.14.1.6: ** Where can I get more technical and business information concerning MySQL and DRBD? * Please visit `http://mysql.com/drbd/'.  File: manual.info, Node: drbd-linux-heartbeat, Next: drbd-architecture, Prev: faqs-drbd, Up: faqs-mysql-drbd-heartbeat B.14.2 Linux Heartbeat ---------------------- In the following section, we provide answers to questions that are most frequently asked about Linux Heartbeat. *Questions* * B.14.2.1: How is Linux Heartbeat licensed? * B.14.2.2: Where can I download Linux Heartbeat? * B.14.2.3: If I find a bug with Linux Heartbeat, to whom do I submit the issue? *Questions and Answers* *B.14.2.1: ** How is Linux Heartbeat licensed? * Linux Heartbeat is licensed under the GPL. *B.14.2.2: ** Where can I download Linux Heartbeat? * Please see `http://linux-ha.org/download/index.html'. *B.14.2.3: ** If I find a bug with Linux Heartbeat, to whom do I submit the issue? * Bug reports should be submitted to `http://www.linux-ha.org/ClusterResourceManager/BugReports'.  File: manual.info, Node: drbd-architecture, Next: drbd-mysql-replication-scale, Prev: drbd-linux-heartbeat, Up: faqs-mysql-drbd-heartbeat B.14.3 DRBD Architecture ------------------------ In the following section, we provide answers to questions that are most frequently asked about DRBD Architecture. *Questions* * B.14.3.1: Is an Active/Active option available for MySQL with DRBD? * B.14.3.2: What MySQL storage engines are supported with DRBD? * B.14.3.3: How long does a failover take? * B.14.3.4: How long does it take to resynchronize data after a failure? * B.14.3.5: Are there any situations where you shouldn't use DRBD? * B.14.3.6: Are there any limitations to DRBD? * B.14.3.7: Where can I find more information on sample architectures? *Questions and Answers* *B.14.3.1: ** Is an Active/Active option available for MySQL with DRBD? * Currently, MySQL does not support Active/Active configurations using DRBD `out of the box'. *B.14.3.2: ** What MySQL storage engines are supported with DRBD? * All of the MySQL transactional storage engines are supported by DRBD, including InnoDB and Falcon. For archived or read-only data, MyISAM or Archive can also be used. *B.14.3.3: ** How long does a failover take? * Failover time is dependent on many things, some of which are configurable. After activating the passive host, MySQL will have to start and run a normal recovery process. If the InnoDB log files have been configured to a large size and there was heavy write traffic, this may take a reasonably long period of time. However, under normal circumstances, failover tends to take less than a minute. *B.14.3.4: ** How long does it take to resynchronize data after a failure? * Resynchronization time depends on how long the two machines are out of communication and how much data was written during that period of time. Resynchronization time is a function of data to be synced, network speed and disk speed. DRBD maintains a bitmap of changed blocks on the primary machine, so only those blocks that have changed will need to be transferred. *B.14.3.5: ** Are there any situations where you shouldn't use DRBD? * See When Not To Use DRBD (http://fghaas.wordpress.com/2007/06/26/when-not-to-use-drbd/). *B.14.3.6: ** Are there any limitations to DRBD? * See DRBD limitations (or are they?) (http://fghaas.wordpress.com/2007/06/18/drbd-limitations-or-are-they/). *B.14.3.7: ** Where can I find more information on sample architectures? * For an example of a Heartbeat R1-compatible resource configuration involving a MySQL database backed by DRBD, see DRBD User's Guide (http://www.drbd.org/users-guide/s-heartbeat-r1.html). For an example of the same DRBD-backed configuration for a MySQL database in a Heartbeat CRM cluster, see DRBD User's Guide (http://www.drbd.org/users-guide/s-heartbeat-crm.html).  File: manual.info, Node: drbd-mysql-replication-scale, Next: drbd-file-systems, Prev: drbd-architecture, Up: faqs-mysql-drbd-heartbeat B.14.4 DRBD and MySQL Replication --------------------------------- In the following section, we provide answers to questions that are most frequently asked about MySQL Replication Scale-out. *Questions* * B.14.4.1: What is the difference between MySQL Cluster and DRBD? * B.14.4.2: What is the difference between MySQL Replication and DRBD? * B.14.4.3: How can I combine MySQL Replication scale-out with DRBD? *Questions and Answers* *B.14.4.1: ** What is the difference between MySQL Cluster and DRBD? * Both MySQL Cluster and DRBD replicate data synchronously. MySQL Cluster leverages a shared-nothing storage architecture in which the cluster can be architected beyond an Active/Passive configuration. DRBD operates at a much lower level within the `stack', at the disk I/O level. For a comparison of various high availability features between these two options, please refer to *Note ha-overview::. *B.14.4.2: ** What is the difference between MySQL Replication and DRBD? * MySQL Replication replicates data asynchronously while DRBD replicates data synchronously. Also, MySQL Replication replicates MySQL statements, while DRBD replicates the underlying block device that stores the MySQL data files. For a comparison of various high availability features between these two options, please refer to the high availability comparison grid, *Note ha-overview::. *B.14.4.3: ** How can I combine MySQL Replication scale-out with DRBD? * MySQL Replication is typically deployed in a Master to many Slaves configuration. In this configuration, having many Slaves provides read scalability. DRBD is used to provide high-availability for the Master MySQL Server in an Active/Passive configuration. This provides for automatic failover, safeguards against data loss, and automatically synchronizes the failed MySQL Master after a failover. The most likely scenario in which MySQL Replication scale-out can be leveraged with DRBD is in the form of attaching replicated MySQL `read-slaves' off of the Active-Master MySQL Server. Since DRBD replicates an entire block device, master information such as the binary logs are also replicated. In this way, all of the slaves can attach to the Virtual IP Address managed by Linux Heartbeat. In the event of a failure, the asynchronous nature of MySQL Replication allows the slaves to continue with the new Active machine as their master with no intervention needed. FIGURE GOES HERE: Active-Master MySQL Server  File: manual.info, Node: drbd-file-systems, Next: drbd-lvm, Prev: drbd-mysql-replication-scale, Up: faqs-mysql-drbd-heartbeat B.14.5 DRBD and File Systems ---------------------------- In the following section, we provide answers to questions that are most frequently asked about DRBD and file systems. *Questions* * B.14.5.1: Can XFS be used with DRBD? *Questions and Answers* *B.14.5.1: ** Can XFS be used with DRBD? * Yes. XFS uses dynamic block size, thus DRBD 0.7 or later is needed.  File: manual.info, Node: drbd-lvm, Next: drbd-virtualization, Prev: drbd-file-systems, Up: faqs-mysql-drbd-heartbeat B.14.6 DRBD and LVM ------------------- In the following section, we provide answers to questions that are most frequently asked about DRBD and LVM. *Questions* * B.14.6.1: Can I use DRBD on top of LVM? * B.14.6.2: Can I use LVM on top of DRBD? * B.14.6.3: Can I use DRBD on top of LVM while at the same time running LVM on top of that DRBD? *Questions and Answers* *B.14.6.1: ** Can I use DRBD on top of LVM? * Yes, DRBD supports on-line resizing. If you enlarge your logical volume that acts as a backing device for DRBD, you can enlarge DRBD itself too, and of course your file system if it supports resizing. *B.14.6.2: ** Can I use LVM on top of DRBD? * Yes, you can use DRBD as a Physical Volume (PV) for LVM. Depending on the default LVM configuration shipped with your distribution, you may need to add the `/dev/drbd*' device files to the `filter' option in your `lvm.conf' so LVM scans your DRBDs for PV signatures. *B.14.6.3: ** Can I use DRBD on top of LVM while at the same time running LVM on top of that DRBD? * This requires careful tuning of your LVM configuration to avoid duplicate PV scans, but yes, it is possible.  File: manual.info, Node: drbd-virtualization, Next: drbd-security, Prev: drbd-lvm, Up: faqs-mysql-drbd-heartbeat B.14.7 DRBD and Virtualization ------------------------------ In the following section, we provide answers to questions that are most frequently asked about DRBD and virtualization. *Questions* * B.14.7.1: Can I use DRBD with OpenVZ? * B.14.7.2: Can I use DRBD with Xen or KVM? *Questions and Answers* *B.14.7.1: ** Can I use DRBD with OpenVZ? * See `http://wiki.openvz.org/HA_cluster_with_DRBD_and_Heartbeat'. *B.14.7.2: ** Can I use DRBD with Xen or KVM? * Yes. If you are looking for professional consultancy or expert commercial support for Xen- or KVM-based virtualization clusters with DRBD, contact LINBIT (`http://www.linbit.com').  File: manual.info, Node: drbd-security, Next: drbd-system-requirements, Prev: drbd-virtualization, Up: faqs-mysql-drbd-heartbeat B.14.8 DRBD and Security ------------------------ In the following section, we provide answers to questions that are most frequently asked about DRBD and security. *Questions* * B.14.8.1: Can I encrypt/compress the exchanged data? * B.14.8.2: Does DRBD do mutual node authentication? *Questions and Answers* *B.14.8.1: ** Can I encrypt/compress the exchanged data? * Yes. But there is no option within DRBD to allow for this. You'll need to leverage a VPN and the network layer should do the rest. *B.14.8.2: ** Does DRBD do mutual node authentication? * Yes, starting with DRBD 8 shared-secret mutual node authentication is supported.  File: manual.info, Node: drbd-system-requirements, Next: drbd-support-consulting, Prev: drbd-security, Up: faqs-mysql-drbd-heartbeat B.14.9 DRBD and System Requirements ----------------------------------- In the following section, we provide answers to questions that are most frequently asked about DRBD and System Requirements. *Questions* * B.14.9.1: What other packages besides DRBD are required? * B.14.9.2: How many machines are required to set up DRBD? * B.14.9.3: Does DRBD only run on Linux? *Questions and Answers* *B.14.9.1: ** What other packages besides DRBD are required? * When using pre-built binary packages, none except a matching kernel, plus packages for `glibc' and your favorite shell. When compiling DRBD from source additional prerequisite packages may be required. They include but are not limited to: * glib-devel * openssl * devel * libgcrypt-devel * glib2-devel * pkgconfig * ncurses-devel * rpm-build * rpm-devel * redhat-rpm-config * gcc * gcc-c++ * bison * flex * gnutls-devel * lm_sensors-devel * net-snmp-devel * python-devel * bzip2-devel * libselinux-devel * perl-DBI * libnet Pre-built x86 and x86_64 packages for specific kernel versions are available with a support subscription from LINBIT. Please note that if the kernel is upgraded, DRBD must be as well. *B.14.9.2: ** How many machines are required to set up DRBD? * Two machines are required to achieve the minimum degree of high availability. Although at any one given point in time one will be primary and one will be secondary, it is better to consider the machines as part of a mirrored pair without a `natural' primary machine. *B.14.9.3: ** Does DRBD only run on Linux? * DRBD is a Linux Kernel Module, and can work with many popular Linux distributions. DRBD is currently not available for non-Linux operating systems.  File: manual.info, Node: drbd-support-consulting, Prev: drbd-system-requirements, Up: faqs-mysql-drbd-heartbeat B.14.10 DRBD and Support and Consulting --------------------------------------- In the following section, we provide answers to questions that are most frequently asked about DRBD and resources. *Questions* * B.14.10.1: Does MySQL offer professional consulting to help with designing a DRBD system? * B.14.10.2: Does MySQL offer support for DRBD and Linux Heartbeat from MySQL? * B.14.10.3: Are pre-built binaries or RPMs available? * B.14.10.4: Does MySQL have documentation to help me with the installation and configuration of DRBD and Linux Heartbeat? * B.14.10.5: Is there a dedicated discussion forum for MySQL High-Availability? * B.14.10.6: Where can I get more information about MySQL for DRBD? *Questions and Answers* *B.14.10.1: ** Does MySQL offer professional consulting to help with designing a DRBD system? * Yes. MySQL offers consulting for the design, installation, configuration, and monitoring of high availability DRBD. For more information concerning a High Availability Jumpstart, please see: http://www.mysql.com/consulting/packaged/scaleout.html. *B.14.10.2: ** Does MySQL offer support for DRBD and Linux Heartbeat from MySQL? * Yes. Support for DRBD is available with an add-on subscription to MySQL Enterprise called "DRBD for MySQL". For more information about support options for DRBD see: `http://mysql.com/products/enterprise/features.html'. For the list of supported Linux distributions, please see: http://www.mysql.com/support/supportedplatforms/enterprise.html. *Note*: DRBD is only available on Linux. DRBD is not available on Windows, MacOS, Solaris, HPUX, AIX, FreeBSD, or other non-Linux platforms. *B.14.10.3: ** Are pre-built binaries or RPMs available? * Yes. `DRBD for MySQL' is an add-on subscription to MySQL Enterprise, which provides pre-built binaries for DRBD. For more information, see: `http://mysql.com/products/enterprise/features.html'. *B.14.10.4: ** Does MySQL have documentation to help me with the installation and configuration of DRBD and Linux Heartbeat? * For MySQL-specific DRBD documentation, see *Note ha-drbd::. For general DRBD documentation, see DRBD User's Guide (http://www.drbd.org/users-guide/). *B.14.10.5: ** Is there a dedicated discussion forum for MySQL High-Availability? * Yes, `http://forums.mysql.com/list.php?144'. *B.14.10.6: ** Where can I get more information about MySQL for DRBD? * For more information about MySQL for DRBD, including a technical white paper please see: http://www.mysql.com/products/enterprise/drbd.html.  File: manual.info, Node: error-handling, Next: news, Prev: faqs, Up: Top Appendix C Errors, Error Codes, and Common Problems *************************************************** * Menu: * error-sources:: Sources of Error Information * error-types:: Types of Error Values * error-messages-server:: Server Error Codes and Messages * error-messages-client:: Client Error Codes and Messages * problems:: Problems and Common Errors This appendix lists common problems and errors that may occur and potential resolutions, in addition to listing the errors that may appear when you call MySQL from any host language. The first section covers problems and resolutions. Detailed information on errors is provided; The first list displays server error messages. The second list displays client program messages.  File: manual.info, Node: error-sources, Next: error-types, Prev: error-handling, Up: error-handling C.1 Sources of Error Information ================================ There are several sources of error information in MySQL: * Each SQL statement executed results in an error code, an SQLSTATE value, and an error message, as described in *Note error-types::. These errors are returned from the server side; see *Note error-messages-server::. * Errors can occur on the client side, usually involving problems communicating with the server; see *Note error-messages-client::. * SQL statement warning and error information is available through the *Note `SHOW WARNINGS': show-warnings. and *Note `SHOW ERRORS': show-errors. statements. The `warning_count' and `error_count' system variables provide counts of the number of warnings and errors. * *Note `SHOW SLAVE STATUS': show-slave-status. statement output includes information about replication errors occurring on the slave side. * *Note `SHOW ENGINE INNODB STATUS': show-engine. statement output includes information about the most recent foreign key error if a *Note `CREATE TABLE': create-table. statement for an *Note `InnoDB': innodb-storage-engine. table fails. * The *Note `perror': perror. program provides information from the command line about error numbers. See *Note perror::. Descriptions of server and client errors are provided later in this Appendix. For information about errors related to *Note `InnoDB': innodb-storage-engine, see *Note innodb-error-handling::.  File: manual.info, Node: error-types, Next: error-messages-server, Prev: error-sources, Up: error-handling C.2 Types of Error Values ========================= When an error occurs in MySQL, the server returns two types of error values: * A MySQL-specific error code. This value is numeric. It is not portable to other database systems. * An SQLSTATE value. The value is a five-character string (for example, `'42S02''). The values are specified by ANSI SQL and ODBC and are more standardized. A message string that provides a textual description of the error is also available. When an error occurs, you can access the MySQL error code, the SQLSTATE value, and the message string using C API functions: * MySQL error code: Call *Note `mysql_errno()': mysql-errno. * SQLSTATE value: Call *Note `mysql_sqlstate()': mysql-sqlstate. * Error message: Call *Note `mysql_error()': mysql-error. For prepared statements, the corresponding error functions are *Note `mysql_stmt_errno()': mysql-stmt-errno, *Note `mysql_stmt_sqlstate()': mysql-stmt-sqlstate, and *Note `mysql_stmt_error()': mysql-stmt-error. All error functions are described in *Note c::. The first two characters of an SQLSTATE value indicate the error class: * `'00'' indicates success. * `'01'' indicates a warning. * `'02'' indicates `not found.' These values are relevant only within the context of cursors and are used to control what happens when a cursor reaches the end of a data set. * Other values indicate an exception.  File: manual.info, Node: error-messages-server, Next: error-messages-client, Prev: error-types, Up: error-handling C.3 Server Error Codes and Messages =================================== MySQL programs have access to several types of error information when the server returns an error. For example, the *Note `mysql': mysql. client program displays errors using the following format: shell> SELECT * FROM no_such_table; ERROR 1146 (42S02): Table 'test.no_such_table' doesn't exist The message displayed contains three types of information: * A numeric error code (`1146'). This number is MySQL-specific and is not portable to other database systems. * A five-character SQLSTATE value (`'42S02''). The values are specified by ANSI SQL and ODBC and are more standardized. Not all MySQL error numbers are mapped to SQLSTATE error codes. The value `'HY000'' (general error) is used for unmapped errors. * A message string that provides a textual description of the error. For error checking, use error codes, not error messages. Error messages do not change often, but it is possible. Also if the database administrator changes the language setting, that affects the language of error messages. Error codes are stable across GA releases of a given MySQL series. Before a series reaches GA status, new codes may still be under development and subject to change. Server error information comes from the following source files. For details about the way that error information is defined, see the MySQL Internals manual, available at `http://forge.mysql.com/wiki/MySQL_Internals'. * Error message information is listed in the `share/errmsg.txt' file. `%d' and `%s' represent numbers and strings, respectively, that are substituted into the Message values when they are displayed. * The Error values listed in `share/errmsg.txt' are used to generate the definitions in the `include/mysqld_error.h' and `include/mysqld_ername.h' MySQL source files. * The SQLSTATE values listed in `share/errmsg.txt' are used to generate the definitions in the `include/sql_state.h' MySQL source file. Because updates are frequent, it is possible that those files will contain additional error information not listed here. * Error: `1000' SQLSTATE: `HY000' (`ER_HASHCHK') Message: hashchk * Error: `1001' SQLSTATE: `HY000' (`ER_NISAMCHK') Message: isamchk * Error: `1002' SQLSTATE: `HY000' (`ER_NO') Message: NO * Error: `1003' SQLSTATE: `HY000' (`ER_YES') Message: YES * Error: `1004' SQLSTATE: `HY000' (`ER_CANT_CREATE_FILE') Message: Can't create file '%s' (errno: %d) * Error: `1005' SQLSTATE: `HY000' (`ER_CANT_CREATE_TABLE') Message: Can't create table '%s' (errno: %d) * Error: `1006' SQLSTATE: `HY000' (`ER_CANT_CREATE_DB') Message: Can't create database '%s' (errno: %d) * Error: `1007' SQLSTATE: `HY000' (`ER_DB_CREATE_EXISTS') Message: Can't create database '%s'; database exists * Error: `1008' SQLSTATE: `HY000' (`ER_DB_DROP_EXISTS') Message: Can't drop database '%s'; database doesn't exist * Error: `1009' SQLSTATE: `HY000' (`ER_DB_DROP_DELETE') Message: Error dropping database (can't delete '%s', errno: %d) * Error: `1010' SQLSTATE: `HY000' (`ER_DB_DROP_RMDIR') Message: Error dropping database (can't rmdir '%s', errno: %d) * Error: `1011' SQLSTATE: `HY000' (`ER_CANT_DELETE_FILE') Message: Error on delete of '%s' (errno: %d) * Error: `1012' SQLSTATE: `HY000' (`ER_CANT_FIND_SYSTEM_REC') Message: Can't read record in system table * Error: `1013' SQLSTATE: `HY000' (`ER_CANT_GET_STAT') Message: Can't get status of '%s' (errno: %d) * Error: `1014' SQLSTATE: `HY000' (`ER_CANT_GET_WD') Message: Can't get working directory (errno: %d) * Error: `1015' SQLSTATE: `HY000' (`ER_CANT_LOCK') Message: Can't lock file (errno: %d) * Error: `1016' SQLSTATE: `HY000' (`ER_CANT_OPEN_FILE') Message: Can't open file: '%s' (errno: %d) * Error: `1017' SQLSTATE: `HY000' (`ER_FILE_NOT_FOUND') Message: Can't find file: '%s' (errno: %d) * Error: `1018' SQLSTATE: `HY000' (`ER_CANT_READ_DIR') Message: Can't read dir of '%s' (errno: %d) * Error: `1019' SQLSTATE: `HY000' (`ER_CANT_SET_WD') Message: Can't change dir to '%s' (errno: %d) * Error: `1020' SQLSTATE: `HY000' (`ER_CHECKREAD') Message: Record has changed since last read in table '%s' * Error: `1021' SQLSTATE: `HY000' (`ER_DISK_FULL') Message: Disk full (%s); waiting for someone to free some space... * Error: `1022' SQLSTATE: `23000' (`ER_DUP_KEY') Message: Can't write; duplicate key in table '%s' * Error: `1023' SQLSTATE: `HY000' (`ER_ERROR_ON_CLOSE') Message: Error on close of '%s' (errno: %d) * Error: `1024' SQLSTATE: `HY000' (`ER_ERROR_ON_READ') Message: Error reading file '%s' (errno: %d) * Error: `1025' SQLSTATE: `HY000' (`ER_ERROR_ON_RENAME') Message: Error on rename of '%s' to '%s' (errno: %d) * Error: `1026' SQLSTATE: `HY000' (`ER_ERROR_ON_WRITE') Message: Error writing file '%s' (errno: %d) * Error: `1027' SQLSTATE: `HY000' (`ER_FILE_USED') Message: '%s' is locked against change * Error: `1028' SQLSTATE: `HY000' (`ER_FILSORT_ABORT') Message: Sort aborted * Error: `1029' SQLSTATE: `HY000' (`ER_FORM_NOT_FOUND') Message: View '%s' doesn't exist for '%s' * Error: `1030' SQLSTATE: `HY000' (`ER_GET_ERRNO') Message: Got error %d from storage engine * Error: `1031' SQLSTATE: `HY000' (`ER_ILLEGAL_HA') Message: Table storage engine for '%s' doesn't have this option * Error: `1032' SQLSTATE: `HY000' (`ER_KEY_NOT_FOUND') Message: Can't find record in '%s' * Error: `1033' SQLSTATE: `HY000' (`ER_NOT_FORM_FILE') Message: Incorrect information in file: '%s' * Error: `1034' SQLSTATE: `HY000' (`ER_NOT_KEYFILE') Message: Incorrect key file for table '%s'; try to repair it * Error: `1035' SQLSTATE: `HY000' (`ER_OLD_KEYFILE') Message: Old key file for table '%s'; repair it! * Error: `1036' SQLSTATE: `HY000' (`ER_OPEN_AS_READONLY') Message: Table '%s' is read only * Error: `1037' SQLSTATE: `HY001' (`ER_OUTOFMEMORY') Message: Out of memory; restart server and try again (needed %d bytes) * Error: `1038' SQLSTATE: `HY001' (`ER_OUT_OF_SORTMEMORY') Message: Out of sort memory; increase server sort buffer size * Error: `1039' SQLSTATE: `HY000' (`ER_UNEXPECTED_EOF') Message: Unexpected EOF found when reading file '%s' (errno: %d) * Error: `1040' SQLSTATE: `08004' (`ER_CON_COUNT_ERROR') Message: Too many connections * Error: `1041' SQLSTATE: `HY000' (`ER_OUT_OF_RESOURCES') Message: Out of memory; check if mysqld or some other process uses all available memory; if not, you may have to use 'ulimit' to allow mysqld to use more memory or you can add more swap space * Error: `1042' SQLSTATE: `08S01' (`ER_BAD_HOST_ERROR') Message: Can't get hostname for your address * Error: `1043' SQLSTATE: `08S01' (`ER_HANDSHAKE_ERROR') Message: Bad handshake * Error: `1044' SQLSTATE: `42000' (`ER_DBACCESS_DENIED_ERROR') Message: Access denied for user '%s'@'%s' to database '%s' * Error: `1045' SQLSTATE: `28000' (`ER_ACCESS_DENIED_ERROR') Message: Access denied for user '%s'@'%s' (using password: %s) * Error: `1046' SQLSTATE: `3D000' (`ER_NO_DB_ERROR') Message: No database selected * Error: `1047' SQLSTATE: `08S01' (`ER_UNKNOWN_COM_ERROR') Message: Unknown command * Error: `1048' SQLSTATE: `23000' (`ER_BAD_NULL_ERROR') Message: Column '%s' cannot be null * Error: `1049' SQLSTATE: `42000' (`ER_BAD_DB_ERROR') Message: Unknown database '%s' * Error: `1050' SQLSTATE: `42S01' (`ER_TABLE_EXISTS_ERROR') Message: Table '%s' already exists * Error: `1051' SQLSTATE: `42S02' (`ER_BAD_TABLE_ERROR') Message: Unknown table '%s' * Error: `1052' SQLSTATE: `23000' (`ER_NON_UNIQ_ERROR') Message: Column '%s' in %s is ambiguous * Error: `1053' SQLSTATE: `08S01' (`ER_SERVER_SHUTDOWN') Message: Server shutdown in progress * Error: `1054' SQLSTATE: `42S22' (`ER_BAD_FIELD_ERROR') Message: Unknown column '%s' in '%s' * Error: `1055' SQLSTATE: `42000' (`ER_WRONG_FIELD_WITH_GROUP') Message: '%s' isn't in GROUP BY * Error: `1056' SQLSTATE: `42000' (`ER_WRONG_GROUP_FIELD') Message: Can't group on '%s' * Error: `1057' SQLSTATE: `42000' (`ER_WRONG_SUM_SELECT') Message: Statement has sum functions and columns in same statement * Error: `1058' SQLSTATE: `21S01' (`ER_WRONG_VALUE_COUNT') Message: Column count doesn't match value count * Error: `1059' SQLSTATE: `42000' (`ER_TOO_LONG_IDENT') Message: Identifier name '%s' is too long * Error: `1060' SQLSTATE: `42S21' (`ER_DUP_FIELDNAME') Message: Duplicate column name '%s' * Error: `1061' SQLSTATE: `42000' (`ER_DUP_KEYNAME') Message: Duplicate key name '%s' * Error: `1062' SQLSTATE: `23000' (`ER_DUP_ENTRY') Message: Duplicate entry '%s' for key %d * Error: `1063' SQLSTATE: `42000' (`ER_WRONG_FIELD_SPEC') Message: Incorrect column specifier for column '%s' * Error: `1064' SQLSTATE: `42000' (`ER_PARSE_ERROR') Message: %s near '%s' at line %d * Error: `1065' SQLSTATE: `42000' (`ER_EMPTY_QUERY') Message: Query was empty * Error: `1066' SQLSTATE: `42000' (`ER_NONUNIQ_TABLE') Message: Not unique table/alias: '%s' * Error: `1067' SQLSTATE: `42000' (`ER_INVALID_DEFAULT') Message: Invalid default value for '%s' * Error: `1068' SQLSTATE: `42000' (`ER_MULTIPLE_PRI_KEY') Message: Multiple primary key defined * Error: `1069' SQLSTATE: `42000' (`ER_TOO_MANY_KEYS') Message: Too many keys specified; max %d keys allowed * Error: `1070' SQLSTATE: `42000' (`ER_TOO_MANY_KEY_PARTS') Message: Too many key parts specified; max %d parts allowed * Error: `1071' SQLSTATE: `42000' (`ER_TOO_LONG_KEY') Message: Specified key was too long; max key length is %d bytes * Error: `1072' SQLSTATE: `42000' (`ER_KEY_COLUMN_DOES_NOT_EXITS') Message: Key column '%s' doesn't exist in table * Error: `1073' SQLSTATE: `42000' (`ER_BLOB_USED_AS_KEY') Message: BLOB column '%s' can't be used in key specification with the used table type * Error: `1074' SQLSTATE: `42000' (`ER_TOO_BIG_FIELDLENGTH') Message: Column length too big for column '%s' (max = %lu); use BLOB or TEXT instead * Error: `1075' SQLSTATE: `42000' (`ER_WRONG_AUTO_KEY') Message: Incorrect table definition; there can be only one auto column and it must be defined as a key * Error: `1076' SQLSTATE: `HY000' (`ER_READY') Message: %s: ready for connections. Version: '%s' socket: '%s' port: %d * Error: `1077' SQLSTATE: `HY000' (`ER_NORMAL_SHUTDOWN') Message: %s: Normal shutdown * Error: `1078' SQLSTATE: `HY000' (`ER_GOT_SIGNAL') Message: %s: Got signal %d. Aborting! * Error: `1079' SQLSTATE: `HY000' (`ER_SHUTDOWN_COMPLETE') Message: %s: Shutdown complete * Error: `1080' SQLSTATE: `08S01' (`ER_FORCING_CLOSE') Message: %s: Forcing close of thread %ld user: '%s' * Error: `1081' SQLSTATE: `08S01' (`ER_IPSOCK_ERROR') Message: Can't create IP socket * Error: `1082' SQLSTATE: `42S12' (`ER_NO_SUCH_INDEX') Message: Table '%s' has no index like the one used in CREATE INDEX; recreate the table * Error: `1083' SQLSTATE: `42000' (`ER_WRONG_FIELD_TERMINATORS') Message: Field separator argument is not what is expected; check the manual * Error: `1084' SQLSTATE: `42000' (`ER_BLOBS_AND_NO_TERMINATED') Message: You can't use fixed rowlength with BLOBs; please use 'fields terminated by' * Error: `1085' SQLSTATE: `HY000' (`ER_TEXTFILE_NOT_READABLE') Message: The file '%s' must be in the database directory or be readable by all * Error: `1086' SQLSTATE: `HY000' (`ER_FILE_EXISTS_ERROR') Message: File '%s' already exists * Error: `1087' SQLSTATE: `HY000' (`ER_LOAD_INFO') Message: Records: %ld Deleted: %ld Skipped: %ld Warnings: %ld * Error: `1088' SQLSTATE: `HY000' (`ER_ALTER_INFO') Message: Records: %ld Duplicates: %ld * Error: `1089' SQLSTATE: `HY000' (`ER_WRONG_SUB_KEY') Message: Incorrect prefix key; the used key part isn't a string, the used length is longer than the key part, or the storage engine doesn't support unique prefix keys * Error: `1090' SQLSTATE: `42000' (`ER_CANT_REMOVE_ALL_FIELDS') Message: You can't delete all columns with ALTER TABLE; use DROP TABLE instead * Error: `1091' SQLSTATE: `42000' (`ER_CANT_DROP_FIELD_OR_KEY') Message: Can't DROP '%s'; check that column/key exists * Error: `1092' SQLSTATE: `HY000' (`ER_INSERT_INFO') Message: Records: %ld Duplicates: %ld Warnings: %ld * Error: `1093' SQLSTATE: `HY000' (`ER_UPDATE_TABLE_USED') Message: You can't specify target table '%s' for update in FROM clause * Error: `1094' SQLSTATE: `HY000' (`ER_NO_SUCH_THREAD') Message: Unknown thread id: %lu * Error: `1095' SQLSTATE: `HY000' (`ER_KILL_DENIED_ERROR') Message: You are not owner of thread %lu * Error: `1096' SQLSTATE: `HY000' (`ER_NO_TABLES_USED') Message: No tables used * Error: `1097' SQLSTATE: `HY000' (`ER_TOO_BIG_SET') Message: Too many strings for column %s and SET * Error: `1098' SQLSTATE: `HY000' (`ER_NO_UNIQUE_LOGFILE') Message: Can't generate a unique log-filename %s.(1-999) * Error: `1099' SQLSTATE: `HY000' (`ER_TABLE_NOT_LOCKED_FOR_WRITE') Message: Table '%s' was locked with a READ lock and can't be updated * Error: `1100' SQLSTATE: `HY000' (`ER_TABLE_NOT_LOCKED') Message: Table '%s' was not locked with LOCK TABLES * Error: `1101' SQLSTATE: `42000' (`ER_BLOB_CANT_HAVE_DEFAULT') Message: BLOB/TEXT column '%s' can't have a default value * Error: `1102' SQLSTATE: `42000' (`ER_WRONG_DB_NAME') Message: Incorrect database name '%s' * Error: `1103' SQLSTATE: `42000' (`ER_WRONG_TABLE_NAME') Message: Incorrect table name '%s' * Error: `1104' SQLSTATE: `42000' (`ER_TOO_BIG_SELECT') Message: The SELECT would examine more than MAX_JOIN_SIZE rows; check your WHERE and use SET SQL_BIG_SELECTS=1 or SET SQL_MAX_JOIN_SIZE=# if the SELECT is okay * Error: `1105' SQLSTATE: `HY000' (`ER_UNKNOWN_ERROR') Message: Unknown error * Error: `1106' SQLSTATE: `42000' (`ER_UNKNOWN_PROCEDURE') Message: Unknown procedure '%s' * Error: `1107' SQLSTATE: `42000' (`ER_WRONG_PARAMCOUNT_TO_PROCEDURE') Message: Incorrect parameter count to procedure '%s' * Error: `1108' SQLSTATE: `HY000' (`ER_WRONG_PARAMETERS_TO_PROCEDURE') Message: Incorrect parameters to procedure '%s' * Error: `1109' SQLSTATE: `42S02' (`ER_UNKNOWN_TABLE') Message: Unknown table '%s' in %s * Error: `1110' SQLSTATE: `42000' (`ER_FIELD_SPECIFIED_TWICE') Message: Column '%s' specified twice * Error: `1111' SQLSTATE: `HY000' (`ER_INVALID_GROUP_FUNC_USE') Message: Invalid use of group function * Error: `1112' SQLSTATE: `42000' (`ER_UNSUPPORTED_EXTENSION') Message: Table '%s' uses an extension that doesn't exist in this MySQL version * Error: `1113' SQLSTATE: `42000' (`ER_TABLE_MUST_HAVE_COLUMNS') Message: A table must have at least 1 column * Error: `1114' SQLSTATE: `HY000' (`ER_RECORD_FILE_FULL') Message: The table '%s' is full * Error: `1115' SQLSTATE: `42000' (`ER_UNKNOWN_CHARACTER_SET') Message: Unknown character set: '%s' * Error: `1116' SQLSTATE: `HY000' (`ER_TOO_MANY_TABLES') Message: Too many tables; MySQL can only use %d tables in a join * Error: `1117' SQLSTATE: `HY000' (`ER_TOO_MANY_FIELDS') Message: Too many columns * Error: `1118' SQLSTATE: `42000' (`ER_TOO_BIG_ROWSIZE') Message: Row size too large. The maximum row size for the used table type, not counting BLOBs, is %ld. You have to change some columns to TEXT or BLOBs * Error: `1119' SQLSTATE: `HY000' (`ER_STACK_OVERRUN') Message: Thread stack overrun: Used: %ld of a %ld stack. Use 'mysqld -O thread_stack=#' to specify a bigger stack if needed * Error: `1120' SQLSTATE: `42000' (`ER_WRONG_OUTER_JOIN') Message: Cross dependency found in OUTER JOIN; examine your ON conditions * Error: `1121' SQLSTATE: `42000' (`ER_NULL_COLUMN_IN_INDEX') Message: Table handler doesn't support NULL in given index. Please change column '%s' to be NOT NULL or use another handler * Error: `1122' SQLSTATE: `HY000' (`ER_CANT_FIND_UDF') Message: Can't load function '%s' * Error: `1123' SQLSTATE: `HY000' (`ER_CANT_INITIALIZE_UDF') Message: Can't initialize function '%s'; %s * Error: `1124' SQLSTATE: `HY000' (`ER_UDF_NO_PATHS') Message: No paths allowed for shared library * Error: `1125' SQLSTATE: `HY000' (`ER_UDF_EXISTS') Message: Function '%s' already exists * Error: `1126' SQLSTATE: `HY000' (`ER_CANT_OPEN_LIBRARY') Message: Can't open shared library '%s' (errno: %d %s) * Error: `1127' SQLSTATE: `HY000' (`ER_CANT_FIND_DL_ENTRY') Message: Can't find symbol '%s' in library * Error: `1128' SQLSTATE: `HY000' (`ER_FUNCTION_NOT_DEFINED') Message: Function '%s' is not defined * Error: `1129' SQLSTATE: `HY000' (`ER_HOST_IS_BLOCKED') Message: Host '%s' is blocked because of many connection errors; unblock with 'mysqladmin flush-hosts' * Error: `1130' SQLSTATE: `HY000' (`ER_HOST_NOT_PRIVILEGED') Message: Host '%s' is not allowed to connect to this MySQL server * Error: `1131' SQLSTATE: `42000' (`ER_PASSWORD_ANONYMOUS_USER') Message: You are using MySQL as an anonymous user and anonymous users are not allowed to change passwords * Error: `1132' SQLSTATE: `42000' (`ER_PASSWORD_NOT_ALLOWED') Message: You must have privileges to update tables in the mysql database to be able to change passwords for others * Error: `1133' SQLSTATE: `42000' (`ER_PASSWORD_NO_MATCH') Message: Can't find any matching row in the user table * Error: `1134' SQLSTATE: `HY000' (`ER_UPDATE_INFO') Message: Rows matched: %ld Changed: %ld Warnings: %ld * Error: `1135' SQLSTATE: `HY000' (`ER_CANT_CREATE_THREAD') Message: Can't create a new thread (errno %d); if you are not out of available memory, you can consult the manual for a possible OS-dependent bug * Error: `1136' SQLSTATE: `21S01' (`ER_WRONG_VALUE_COUNT_ON_ROW') Message: Column count doesn't match value count at row %ld * Error: `1137' SQLSTATE: `HY000' (`ER_CANT_REOPEN_TABLE') Message: Can't reopen table: '%s' * Error: `1138' SQLSTATE: `22004' (`ER_INVALID_USE_OF_NULL') Message: Invalid use of NULL value * Error: `1139' SQLSTATE: `42000' (`ER_REGEXP_ERROR') Message: Got error '%s' from regexp * Error: `1140' SQLSTATE: `42000' (`ER_MIX_OF_GROUP_FUNC_AND_FIELDS') Message: Mixing of GROUP columns (MIN(),MAX(),COUNT(),...) with no GROUP columns is illegal if there is no GROUP BY clause * Error: `1141' SQLSTATE: `42000' (`ER_NONEXISTING_GRANT') Message: There is no such grant defined for user '%s' on host '%s' * Error: `1142' SQLSTATE: `42000' (`ER_TABLEACCESS_DENIED_ERROR') Message: %s command denied to user '%s'@'%s' for table '%s' * Error: `1143' SQLSTATE: `42000' (`ER_COLUMNACCESS_DENIED_ERROR') Message: %s command denied to user '%s'@'%s' for column '%s' in table '%s' * Error: `1144' SQLSTATE: `42000' (`ER_ILLEGAL_GRANT_FOR_TABLE') Message: Illegal GRANT/REVOKE command; please consult the manual to see which privileges can be used * Error: `1145' SQLSTATE: `42000' (`ER_GRANT_WRONG_HOST_OR_USER') Message: The host or user argument to GRANT is too long * Error: `1146' SQLSTATE: `42S02' (`ER_NO_SUCH_TABLE') Message: Table '%s.%s' doesn't exist * Error: `1147' SQLSTATE: `42000' (`ER_NONEXISTING_TABLE_GRANT') Message: There is no such grant defined for user '%s' on host '%s' on table '%s' * Error: `1148' SQLSTATE: `42000' (`ER_NOT_ALLOWED_COMMAND') Message: The used command is not allowed with this MySQL version * Error: `1149' SQLSTATE: `42000' (`ER_SYNTAX_ERROR') Message: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use * Error: `1150' SQLSTATE: `HY000' (`ER_DELAYED_CANT_CHANGE_LOCK') Message: Delayed insert thread couldn't get requested lock for table %s * Error: `1151' SQLSTATE: `HY000' (`ER_TOO_MANY_DELAYED_THREADS') Message: Too many delayed threads in use * Error: `1152' SQLSTATE: `08S01' (`ER_ABORTING_CONNECTION') Message: Aborted connection %ld to db: '%s' user: '%s' (%s) * Error: `1153' SQLSTATE: `08S01' (`ER_NET_PACKET_TOO_LARGE') Message: Got a packet bigger than 'max_allowed_packet' bytes * Error: `1154' SQLSTATE: `08S01' (`ER_NET_READ_ERROR_FROM_PIPE') Message: Got a read error from the connection pipe * Error: `1155' SQLSTATE: `08S01' (`ER_NET_FCNTL_ERROR') Message: Got an error from fcntl() * Error: `1156' SQLSTATE: `08S01' (`ER_NET_PACKETS_OUT_OF_ORDER') Message: Got packets out of order * Error: `1157' SQLSTATE: `08S01' (`ER_NET_UNCOMPRESS_ERROR') Message: Couldn't uncompress communication packet * Error: `1158' SQLSTATE: `08S01' (`ER_NET_READ_ERROR') Message: Got an error reading communication packets * Error: `1159' SQLSTATE: `08S01' (`ER_NET_READ_INTERRUPTED') Message: Got timeout reading communication packets * Error: `1160' SQLSTATE: `08S01' (`ER_NET_ERROR_ON_WRITE') Message: Got an error writing communication packets * Error: `1161' SQLSTATE: `08S01' (`ER_NET_WRITE_INTERRUPTED') Message: Got timeout writing communication packets * Error: `1162' SQLSTATE: `42000' (`ER_TOO_LONG_STRING') Message: Result string is longer than 'max_allowed_packet' bytes * Error: `1163' SQLSTATE: `42000' (`ER_TABLE_CANT_HANDLE_BLOB') Message: The used table type doesn't support BLOB/TEXT columns * Error: `1164' SQLSTATE: `42000' (`ER_TABLE_CANT_HANDLE_AUTO_INCREMENT') Message: The used table type doesn't support AUTO_INCREMENT columns * Error: `1165' SQLSTATE: `HY000' (`ER_DELAYED_INSERT_TABLE_LOCKED') Message: INSERT DELAYED can't be used with table '%s' because it is locked with LOCK TABLES * Error: `1166' SQLSTATE: `42000' (`ER_WRONG_COLUMN_NAME') Message: Incorrect column name '%s' * Error: `1167' SQLSTATE: `42000' (`ER_WRONG_KEY_COLUMN') Message: The used storage engine can't index column '%s' * Error: `1168' SQLSTATE: `HY000' (`ER_WRONG_MRG_TABLE') Message: Unable to open underlying table which is differently defined or of non-MyISAM type or doesn't exist * Error: `1169' SQLSTATE: `23000' (`ER_DUP_UNIQUE') Message: Can't write, because of unique constraint, to table '%s' * Error: `1170' SQLSTATE: `42000' (`ER_BLOB_KEY_WITHOUT_LENGTH') Message: BLOB/TEXT column '%s' used in key specification without a key length * Error: `1171' SQLSTATE: `42000' (`ER_PRIMARY_CANT_HAVE_NULL') Message: All parts of a PRIMARY KEY must be NOT NULL; if you need NULL in a key, use UNIQUE instead * Error: `1172' SQLSTATE: `42000' (`ER_TOO_MANY_ROWS') Message: Result consisted of more than one row * Error: `1173' SQLSTATE: `42000' (`ER_REQUIRES_PRIMARY_KEY') Message: This table type requires a primary key * Error: `1174' SQLSTATE: `HY000' (`ER_NO_RAID_COMPILED') Message: This version of MySQL is not compiled with RAID support * Error: `1175' SQLSTATE: `HY000' (`ER_UPDATE_WITHOUT_KEY_IN_SAFE_MODE') Message: You are using safe update mode and you tried to update a table without a WHERE that uses a KEY column * Error: `1176' SQLSTATE: `42000' (`ER_KEY_DOES_NOT_EXITS') Message: Key '%s' doesn't exist in table '%s' * Error: `1177' SQLSTATE: `42000' (`ER_CHECK_NO_SUCH_TABLE') Message: Can't open table * Error: `1178' SQLSTATE: `42000' (`ER_CHECK_NOT_IMPLEMENTED') Message: The storage engine for the table doesn't support %s * Error: `1179' SQLSTATE: `25000' (`ER_CANT_DO_THIS_DURING_AN_TRANSACTION') Message: You are not allowed to execute this command in a transaction * Error: `1180' SQLSTATE: `HY000' (`ER_ERROR_DURING_COMMIT') Message: Got error %d during COMMIT * Error: `1181' SQLSTATE: `HY000' (`ER_ERROR_DURING_ROLLBACK') Message: Got error %d during ROLLBACK * Error: `1182' SQLSTATE: `HY000' (`ER_ERROR_DURING_FLUSH_LOGS') Message: Got error %d during FLUSH_LOGS * Error: `1183' SQLSTATE: `HY000' (`ER_ERROR_DURING_CHECKPOINT') Message: Got error %d during CHECKPOINT * Error: `1184' SQLSTATE: `08S01' (`ER_NEW_ABORTING_CONNECTION') Message: Aborted connection %ld to db: '%s' user: '%s' host: '%s' (%s) * Error: `1185' SQLSTATE: `HY000' (`ER_DUMP_NOT_IMPLEMENTED') Message: The storage engine for the table does not support binary table dump * Error: `1186' SQLSTATE: `HY000' (`ER_FLUSH_MASTER_BINLOG_CLOSED') Message: Binlog closed, cannot RESET MASTER * Error: `1187' SQLSTATE: `HY000' (`ER_INDEX_REBUILD') Message: Failed rebuilding the index of dumped table '%s' * Error: `1188' SQLSTATE: `HY000' (`ER_MASTER') Message: Error from master: '%s' * Error: `1189' SQLSTATE: `08S01' (`ER_MASTER_NET_READ') Message: Net error reading from master * Error: `1190' SQLSTATE: `08S01' (`ER_MASTER_NET_WRITE') Message: Net error writing to master * Error: `1191' SQLSTATE: `HY000' (`ER_FT_MATCHING_KEY_NOT_FOUND') Message: Can't find FULLTEXT index matching the column list * Error: `1192' SQLSTATE: `HY000' (`ER_LOCK_OR_ACTIVE_TRANSACTION') Message: Can't execute the given command because you have active locked tables or an active transaction * Error: `1193' SQLSTATE: `HY000' (`ER_UNKNOWN_SYSTEM_VARIABLE') Message: Unknown system variable '%s' * Error: `1194' SQLSTATE: `HY000' (`ER_CRASHED_ON_USAGE') Message: Table '%s' is marked as crashed and should be repaired * Error: `1195' SQLSTATE: `HY000' (`ER_CRASHED_ON_REPAIR') Message: Table '%s' is marked as crashed and last (automatic?) repair failed * Error: `1196' SQLSTATE: `HY000' (`ER_WARNING_NOT_COMPLETE_ROLLBACK') Message: Some non-transactional changed tables couldn't be rolled back * Error: `1197' SQLSTATE: `HY000' (`ER_TRANS_CACHE_FULL') Message: Multi-statement transaction required more than 'max_binlog_cache_size' bytes of storage; increase this mysqld variable and try again * Error: `1198' SQLSTATE: `HY000' (`ER_SLAVE_MUST_STOP') Message: This operation cannot be performed with a running slave; run STOP SLAVE first * Error: `1199' SQLSTATE: `HY000' (`ER_SLAVE_NOT_RUNNING') Message: This operation requires a running slave; configure slave and do START SLAVE * Error: `1200' SQLSTATE: `HY000' (`ER_BAD_SLAVE') Message: The server is not configured as slave; fix in config file or with CHANGE MASTER TO * Error: `1201' SQLSTATE: `HY000' (`ER_MASTER_INFO') Message: Could not initialize master info structure; more error messages can be found in the MySQL error log * Error: `1202' SQLSTATE: `HY000' (`ER_SLAVE_THREAD') Message: Could not create slave thread; check system resources * Error: `1203' SQLSTATE: `42000' (`ER_TOO_MANY_USER_CONNECTIONS') Message: User %s already has more than 'max_user_connections' active connections * Error: `1204' SQLSTATE: `HY000' (`ER_SET_CONSTANTS_ONLY') Message: You may only use constant expressions with SET * Error: `1205' SQLSTATE: `HY000' (`ER_LOCK_WAIT_TIMEOUT') Message: Lock wait timeout exceeded; try restarting transaction * Error: `1206' SQLSTATE: `HY000' (`ER_LOCK_TABLE_FULL') Message: The total number of locks exceeds the lock table size * Error: `1207' SQLSTATE: `25000' (`ER_READ_ONLY_TRANSACTION') Message: Update locks cannot be acquired during a READ UNCOMMITTED transaction * Error: `1208' SQLSTATE: `HY000' (`ER_DROP_DB_WITH_READ_LOCK') Message: DROP DATABASE not allowed while thread is holding global read lock * Error: `1209' SQLSTATE: `HY000' (`ER_CREATE_DB_WITH_READ_LOCK') Message: CREATE DATABASE not allowed while thread is holding global read lock * Error: `1210' SQLSTATE: `HY000' (`ER_WRONG_ARGUMENTS') Message: Incorrect arguments to %s * Error: `1211' SQLSTATE: `42000' (`ER_NO_PERMISSION_TO_CREATE_USER') Message: '%s'@'%s' is not allowed to create new users * Error: `1212' SQLSTATE: `HY000' (`ER_UNION_TABLES_IN_DIFFERENT_DIR') Message: Incorrect table definition; all MERGE tables must be in the same database * Error: `1213' SQLSTATE: `40001' (`ER_LOCK_DEADLOCK') Message: Deadlock found when trying to get lock; try restarting transaction * Error: `1214' SQLSTATE: `HY000' (`ER_TABLE_CANT_HANDLE_FT') Message: The used table type doesn't support FULLTEXT indexes * Error: `1215' SQLSTATE: `HY000' (`ER_CANNOT_ADD_FOREIGN') Message: Cannot add foreign key constraint * Error: `1216' SQLSTATE: `23000' (`ER_NO_REFERENCED_ROW') Message: Cannot add or update a child row: a foreign key constraint fails * Error: `1217' SQLSTATE: `23000' (`ER_ROW_IS_REFERENCED') Message: Cannot delete or update a parent row: a foreign key constraint fails * Error: `1218' SQLSTATE: `08S01' (`ER_CONNECT_TO_MASTER') Message: Error connecting to master: %s * Error: `1219' SQLSTATE: `HY000' (`ER_QUERY_ON_MASTER') Message: Error running query on master: %s * Error: `1220' SQLSTATE: `HY000' (`ER_ERROR_WHEN_EXECUTING_COMMAND') Message: Error when executing command %s: %s * Error: `1221' SQLSTATE: `HY000' (`ER_WRONG_USAGE') Message: Incorrect usage of %s and %s * Error: `1222' SQLSTATE: `21000' (`ER_WRONG_NUMBER_OF_COLUMNS_IN_SELECT') Message: The used SELECT statements have a different number of columns * Error: `1223' SQLSTATE: `HY000' (`ER_CANT_UPDATE_WITH_READLOCK') Message: Can't execute the query because you have a conflicting read lock * Error: `1224' SQLSTATE: `HY000' (`ER_MIXING_NOT_ALLOWED') Message: Mixing of transactional and non-transactional tables is disabled * Error: `1225' SQLSTATE: `HY000' (`ER_DUP_ARGUMENT') Message: Option '%s' used twice in statement * Error: `1226' SQLSTATE: `42000' (`ER_USER_LIMIT_REACHED') Message: User '%s' has exceeded the '%s' resource (current value: %ld) * Error: `1227' SQLSTATE: `42000' (`ER_SPECIFIC_ACCESS_DENIED_ERROR') Message: Access denied; you need the %s privilege for this operation * Error: `1228' SQLSTATE: `HY000' (`ER_LOCAL_VARIABLE') Message: Variable '%s' is a SESSION variable and can't be used with SET GLOBAL * Error: `1229' SQLSTATE: `HY000' (`ER_GLOBAL_VARIABLE') Message: Variable '%s' is a GLOBAL variable and should be set with SET GLOBAL * Error: `1230' SQLSTATE: `42000' (`ER_NO_DEFAULT') Message: Variable '%s' doesn't have a default value * Error: `1231' SQLSTATE: `42000' (`ER_WRONG_VALUE_FOR_VAR') Message: Variable '%s' can't be set to the value of '%s' * Error: `1232' SQLSTATE: `42000' (`ER_WRONG_TYPE_FOR_VAR') Message: Incorrect argument type to variable '%s' * Error: `1233' SQLSTATE: `HY000' (`ER_VAR_CANT_BE_READ') Message: Variable '%s' can only be set, not read * Error: `1234' SQLSTATE: `42000' (`ER_CANT_USE_OPTION_HERE') Message: Incorrect usage/placement of '%s' * Error: `1235' SQLSTATE: `42000' (`ER_NOT_SUPPORTED_YET') Message: This version of MySQL doesn't yet support '%s' * Error: `1236' SQLSTATE: `HY000' (`ER_MASTER_FATAL_ERROR_READING_BINLOG') Message: Got fatal error %d from master when reading data from binary log: '%s' * Error: `1237' SQLSTATE: `HY000' (`ER_SLAVE_IGNORED_TABLE') Message: Slave SQL thread ignored the query because of replicate-*-table rules * Error: `1238' SQLSTATE: `HY000' (`ER_INCORRECT_GLOBAL_LOCAL_VAR') Message: Variable '%s' is a %s variable * Error: `1239' SQLSTATE: `42000' (`ER_WRONG_FK_DEF') Message: Incorrect foreign key definition for '%s': %s * Error: `1240' SQLSTATE: `HY000' (`ER_KEY_REF_DO_NOT_MATCH_TABLE_REF') Message: Key reference and table reference don't match * Error: `1241' SQLSTATE: `21000' (`ER_OPERAND_COLUMNS') Message: Operand should contain %d column(s) * Error: `1242' SQLSTATE: `21000' (`ER_SUBQUERY_NO_1_ROW') Message: Subquery returns more than 1 row * Error: `1243' SQLSTATE: `HY000' (`ER_UNKNOWN_STMT_HANDLER') Message: Unknown prepared statement handler (%.*s) given to %s * Error: `1244' SQLSTATE: `HY000' (`ER_CORRUPT_HELP_DB') Message: Help database is corrupt or does not exist * Error: `1245' SQLSTATE: `HY000' (`ER_CYCLIC_REFERENCE') Message: Cyclic reference on subqueries * Error: `1246' SQLSTATE: `HY000' (`ER_AUTO_CONVERT') Message: Converting column '%s' from %s to %s * Error: `1247' SQLSTATE: `42S22' (`ER_ILLEGAL_REFERENCE') Message: Reference '%s' not supported (%s) * Error: `1248' SQLSTATE: `42000' (`ER_DERIVED_MUST_HAVE_ALIAS') Message: Every derived table must have its own alias * Error: `1249' SQLSTATE: `01000' (`ER_SELECT_REDUCED') Message: Select %u was reduced during optimization * Error: `1250' SQLSTATE: `42000' (`ER_TABLENAME_NOT_ALLOWED_HERE') Message: Table '%s' from one of the SELECTs cannot be used in %s * Error: `1251' SQLSTATE: `08004' (`ER_NOT_SUPPORTED_AUTH_MODE') Message: Client does not support authentication protocol requested by server; consider upgrading MySQL client * Error: `1252' SQLSTATE: `42000' (`ER_SPATIAL_CANT_HAVE_NULL') Message: All parts of a SPATIAL index must be NOT NULL * Error: `1253' SQLSTATE: `42000' (`ER_COLLATION_CHARSET_MISMATCH') Message: COLLATION '%s' is not valid for CHARACTER SET '%s' * Error: `1254' SQLSTATE: `HY000' (`ER_SLAVE_WAS_RUNNING') Message: Slave is already running * Error: `1255' SQLSTATE: `HY000' (`ER_SLAVE_WAS_NOT_RUNNING') Message: Slave already has been stopped * Error: `1256' SQLSTATE: `HY000' (`ER_TOO_BIG_FOR_UNCOMPRESS') Message: Uncompressed data size too large; the maximum size is %d (probably, length of uncompressed data was corrupted) * Error: `1257' SQLSTATE: `HY000' (`ER_ZLIB_Z_MEM_ERROR') Message: ZLIB: Not enough memory * Error: `1258' SQLSTATE: `HY000' (`ER_ZLIB_Z_BUF_ERROR') Message: ZLIB: Not enough room in the output buffer (probably, length of uncompressed data was corrupted) * Error: `1259' SQLSTATE: `HY000' (`ER_ZLIB_Z_DATA_ERROR') Message: ZLIB: Input data corrupted * Error: `1260' SQLSTATE: `HY000' (`ER_CUT_VALUE_GROUP_CONCAT') Message: %d line(s) were cut by GROUP_CONCAT() * Error: `1261' SQLSTATE: `01000' (`ER_WARN_TOO_FEW_RECORDS') Message: Row %ld doesn't contain data for all columns * Error: `1262' SQLSTATE: `01000' (`ER_WARN_TOO_MANY_RECORDS') Message: Row %ld was truncated; it contained more data than there were input columns * Error: `1263' SQLSTATE: `22004' (`ER_WARN_NULL_TO_NOTNULL') Message: Column set to default value; NULL supplied to NOT NULL column '%s' at row %ld * Error: `1264' SQLSTATE: `22003' (`ER_WARN_DATA_OUT_OF_RANGE') Message: Out of range value for column '%s' at row %ld * Error: `1265' SQLSTATE: `01000' (`WARN_DATA_TRUNCATED') Message: Data truncated for column '%s' at row %ld * Error: `1266' SQLSTATE: `HY000' (`ER_WARN_USING_OTHER_HANDLER') Message: Using storage engine %s for table '%s' * Error: `1267' SQLSTATE: `HY000' (`ER_CANT_AGGREGATE_2COLLATIONS') Message: Illegal mix of collations (%s,%s) and (%s,%s) for operation '%s' * Error: `1268' SQLSTATE: `HY000' (`ER_DROP_USER') Message: Cannot drop one or more of the requested users * Error: `1269' SQLSTATE: `HY000' (`ER_REVOKE_GRANTS') Message: Can't revoke all privileges for one or more of the requested users * Error: `1270' SQLSTATE: `HY000' (`ER_CANT_AGGREGATE_3COLLATIONS') Message: Illegal mix of collations (%s,%s), (%s,%s), (%s,%s) for operation '%s' * Error: `1271' SQLSTATE: `HY000' (`ER_CANT_AGGREGATE_NCOLLATIONS') Message: Illegal mix of collations for operation '%s' * Error: `1272' SQLSTATE: `HY000' (`ER_VARIABLE_IS_NOT_STRUCT') Message: Variable '%s' is not a variable component (can't be used as XXXX.variable_name) * Error: `1273' SQLSTATE: `HY000' (`ER_UNKNOWN_COLLATION') Message: Unknown collation: '%s' * Error: `1274' SQLSTATE: `HY000' (`ER_SLAVE_IGNORED_SSL_PARAMS') Message: SSL parameters in CHANGE MASTER are ignored because this MySQL slave was compiled without SSL support; they can be used later if MySQL slave with SSL is started * Error: `1275' SQLSTATE: `HY000' (`ER_SERVER_IS_IN_SECURE_AUTH_MODE') Message: Server is running in -secure-auth mode, but '%s'@'%s' has a password in the old format; please change the password to the new format * Error: `1276' SQLSTATE: `HY000' (`ER_WARN_FIELD_RESOLVED') Message: Field or reference '%s%s%s%s%s' of SELECT #%d was resolved in SELECT #%d * Error: `1277' SQLSTATE: `HY000' (`ER_BAD_SLAVE_UNTIL_COND') Message: Incorrect parameter or combination of parameters for START SLAVE UNTIL * Error: `1278' SQLSTATE: `HY000' (`ER_MISSING_SKIP_SLAVE') Message: It is recommended to use -skip-slave-start when doing step-by-step replication with START SLAVE UNTIL; otherwise, you will get problems if you get an unexpected slave's mysqld restart * Error: `1279' SQLSTATE: `HY000' (`ER_UNTIL_COND_IGNORED') Message: SQL thread is not to be started so UNTIL options are ignored * Error: `1280' SQLSTATE: `42000' (`ER_WRONG_NAME_FOR_INDEX') Message: Incorrect index name '%s' * Error: `1281' SQLSTATE: `42000' (`ER_WRONG_NAME_FOR_CATALOG') Message: Incorrect catalog name '%s' * Error: `1282' SQLSTATE: `HY000' (`ER_WARN_QC_RESIZE') Message: Query cache failed to set size %lu; new query cache size is %lu * Error: `1283' SQLSTATE: `HY000' (`ER_BAD_FT_COLUMN') Message: Column '%s' cannot be part of FULLTEXT index * Error: `1284' SQLSTATE: `HY000' (`ER_UNKNOWN_KEY_CACHE') Message: Unknown key cache '%s' * Error: `1285' SQLSTATE: `HY000' (`ER_WARN_HOSTNAME_WONT_WORK') Message: MySQL is started in -skip-name-resolve mode; you must restart it without this switch for this grant to work * Error: `1286' SQLSTATE: `42000' (`ER_UNKNOWN_STORAGE_ENGINE') Message: Unknown table engine '%s' * Error: `1287' SQLSTATE: `HY000' (`ER_WARN_DEPRECATED_SYNTAX') Message: '%s' is deprecated and will be removed in a future release. Please use %s instead * Error: `1288' SQLSTATE: `HY000' (`ER_NON_UPDATABLE_TABLE') Message: The target table %s of the %s is not updatable * Error: `1289' SQLSTATE: `HY000' (`ER_FEATURE_DISABLED') Message: The '%s' feature is disabled; you need MySQL built with '%s' to have it working * Error: `1290' SQLSTATE: `HY000' (`ER_OPTION_PREVENTS_STATEMENT') Message: The MySQL server is running with the %s option so it cannot execute this statement * Error: `1291' SQLSTATE: `HY000' (`ER_DUPLICATED_VALUE_IN_TYPE') Message: Column '%s' has duplicated value '%s' in %s * Error: `1292' SQLSTATE: `22007' (`ER_TRUNCATED_WRONG_VALUE') Message: Truncated incorrect %s value: '%s' * Error: `1293' SQLSTATE: `HY000' (`ER_TOO_MUCH_AUTO_TIMESTAMP_COLS') Message: Incorrect table definition; there can be only one TIMESTAMP column with CURRENT_TIMESTAMP in DEFAULT or ON UPDATE clause * Error: `1294' SQLSTATE: `HY000' (`ER_INVALID_ON_UPDATE') Message: Invalid ON UPDATE clause for '%s' column * Error: `1295' SQLSTATE: `HY000' (`ER_UNSUPPORTED_PS') Message: This command is not supported in the prepared statement protocol yet * Error: `1296' SQLSTATE: `HY000' (`ER_GET_ERRMSG') Message: Got error %d '%s' from %s * Error: `1297' SQLSTATE: `HY000' (`ER_GET_TEMPORARY_ERRMSG') Message: Got temporary error %d '%s' from %s * Error: `1298' SQLSTATE: `HY000' (`ER_UNKNOWN_TIME_ZONE') Message: Unknown or incorrect time zone: '%s' * Error: `1299' SQLSTATE: `HY000' (`ER_WARN_INVALID_TIMESTAMP') Message: Invalid TIMESTAMP value in column '%s' at row %ld * Error: `1300' SQLSTATE: `HY000' (`ER_INVALID_CHARACTER_STRING') Message: Invalid %s character string: '%s' * Error: `1301' SQLSTATE: `HY000' (`ER_WARN_ALLOWED_PACKET_OVERFLOWED') Message: Result of %s() was larger than max_allowed_packet (%ld) - truncated * Error: `1302' SQLSTATE: `HY000' (`ER_CONFLICTING_DECLARATIONS') Message: Conflicting declarations: '%s%s' and '%s%s' * Error: `1303' SQLSTATE: `2F003' (`ER_SP_NO_RECURSIVE_CREATE') Message: Can't create a %s from within another stored routine * Error: `1304' SQLSTATE: `42000' (`ER_SP_ALREADY_EXISTS') Message: %s %s already exists * Error: `1305' SQLSTATE: `42000' (`ER_SP_DOES_NOT_EXIST') Message: %s %s does not exist * Error: `1306' SQLSTATE: `HY000' (`ER_SP_DROP_FAILED') Message: Failed to DROP %s %s * Error: `1307' SQLSTATE: `HY000' (`ER_SP_STORE_FAILED') Message: Failed to CREATE %s %s * Error: `1308' SQLSTATE: `42000' (`ER_SP_LILABEL_MISMATCH') Message: %s with no matching label: %s * Error: `1309' SQLSTATE: `42000' (`ER_SP_LABEL_REDEFINE') Message: Redefining label %s * Error: `1310' SQLSTATE: `42000' (`ER_SP_LABEL_MISMATCH') Message: End-label %s without match * Error: `1311' SQLSTATE: `01000' (`ER_SP_UNINIT_VAR') Message: Referring to uninitialized variable %s * Error: `1312' SQLSTATE: `0A000' (`ER_SP_BADSELECT') Message: PROCEDURE %s can't return a result set in the given context * Error: `1313' SQLSTATE: `42000' (`ER_SP_BADRETURN') Message: RETURN is only allowed in a FUNCTION * Error: `1314' SQLSTATE: `0A000' (`ER_SP_BADSTATEMENT') Message: %s is not allowed in stored procedures * Error: `1315' SQLSTATE: `42000' (`ER_UPDATE_LOG_DEPRECATED_IGNORED') Message: The update log is deprecated and replaced by the binary log; SET SQL_LOG_UPDATE has been ignored. This option will be removed in MySQL 5.6. * Error: `1316' SQLSTATE: `42000' (`ER_UPDATE_LOG_DEPRECATED_TRANSLATED') Message: The update log is deprecated and replaced by the binary log; SET SQL_LOG_UPDATE has been translated to SET SQL_LOG_BIN. This option will be removed in MySQL 5.6. * Error: `1317' SQLSTATE: `70100' (`ER_QUERY_INTERRUPTED') Message: Query execution was interrupted * Error: `1318' SQLSTATE: `42000' (`ER_SP_WRONG_NO_OF_ARGS') Message: Incorrect number of arguments for %s %s; expected %u, got %u * Error: `1319' SQLSTATE: `42000' (`ER_SP_COND_MISMATCH') Message: Undefined CONDITION: %s * Error: `1320' SQLSTATE: `42000' (`ER_SP_NORETURN') Message: No RETURN found in FUNCTION %s * Error: `1321' SQLSTATE: `2F005' (`ER_SP_NORETURNEND') Message: FUNCTION %s ended without RETURN * Error: `1322' SQLSTATE: `42000' (`ER_SP_BAD_CURSOR_QUERY') Message: Cursor statement must be a SELECT * Error: `1323' SQLSTATE: `42000' (`ER_SP_BAD_CURSOR_SELECT') Message: Cursor SELECT must not have INTO * Error: `1324' SQLSTATE: `42000' (`ER_SP_CURSOR_MISMATCH') Message: Undefined CURSOR: %s * Error: `1325' SQLSTATE: `24000' (`ER_SP_CURSOR_ALREADY_OPEN') Message: Cursor is already open * Error: `1326' SQLSTATE: `24000' (`ER_SP_CURSOR_NOT_OPEN') Message: Cursor is not open * Error: `1327' SQLSTATE: `42000' (`ER_SP_UNDECLARED_VAR') Message: Undeclared variable: %s * Error: `1328' SQLSTATE: `HY000' (`ER_SP_WRONG_NO_OF_FETCH_ARGS') Message: Incorrect number of FETCH variables * Error: `1329' SQLSTATE: `02000' (`ER_SP_FETCH_NO_DATA') Message: No data - zero rows fetched, selected, or processed * Error: `1330' SQLSTATE: `42000' (`ER_SP_DUP_PARAM') Message: Duplicate parameter: %s * Error: `1331' SQLSTATE: `42000' (`ER_SP_DUP_VAR') Message: Duplicate variable: %s * Error: `1332' SQLSTATE: `42000' (`ER_SP_DUP_COND') Message: Duplicate condition: %s * Error: `1333' SQLSTATE: `42000' (`ER_SP_DUP_CURS') Message: Duplicate cursor: %s * Error: `1334' SQLSTATE: `HY000' (`ER_SP_CANT_ALTER') Message: Failed to ALTER %s %s * Error: `1335' SQLSTATE: `0A000' (`ER_SP_SUBSELECT_NYI') Message: Subquery value not supported * Error: `1336' SQLSTATE: `0A000' (`ER_STMT_NOT_ALLOWED_IN_SF_OR_TRG') Message: %s is not allowed in stored function or trigger * Error: `1337' SQLSTATE: `42000' (`ER_SP_VARCOND_AFTER_CURSHNDLR') Message: Variable or condition declaration after cursor or handler declaration * Error: `1338' SQLSTATE: `42000' (`ER_SP_CURSOR_AFTER_HANDLER') Message: Cursor declaration after handler declaration * Error: `1339' SQLSTATE: `20000' (`ER_SP_CASE_NOT_FOUND') Message: Case not found for CASE statement * Error: `1340' SQLSTATE: `HY000' (`ER_FPARSER_TOO_BIG_FILE') Message: Configuration file '%s' is too big * Error: `1341' SQLSTATE: `HY000' (`ER_FPARSER_BAD_HEADER') Message: Malformed file type header in file '%s' * Error: `1342' SQLSTATE: `HY000' (`ER_FPARSER_EOF_IN_COMMENT') Message: Unexpected end of file while parsing comment '%s' * Error: `1343' SQLSTATE: `HY000' (`ER_FPARSER_ERROR_IN_PARAMETER') Message: Error while parsing parameter '%s' (line: '%s') * Error: `1344' SQLSTATE: `HY000' (`ER_FPARSER_EOF_IN_UNKNOWN_PARAMETER') Message: Unexpected end of file while skipping unknown parameter '%s' * Error: `1345' SQLSTATE: `HY000' (`ER_VIEW_NO_EXPLAIN') Message: EXPLAIN/SHOW can not be issued; lacking privileges for underlying table * Error: `1346' SQLSTATE: `HY000' (`ER_FRM_UNKNOWN_TYPE') Message: File '%s' has unknown type '%s' in its header * Error: `1347' SQLSTATE: `HY000' (`ER_WRONG_OBJECT') Message: '%s.%s' is not %s * Error: `1348' SQLSTATE: `HY000' (`ER_NONUPDATEABLE_COLUMN') Message: Column '%s' is not updatable * Error: `1349' SQLSTATE: `HY000' (`ER_VIEW_SELECT_DERIVED') Message: View's SELECT contains a subquery in the FROM clause * Error: `1350' SQLSTATE: `HY000' (`ER_VIEW_SELECT_CLAUSE') Message: View's SELECT contains a '%s' clause * Error: `1351' SQLSTATE: `HY000' (`ER_VIEW_SELECT_VARIABLE') Message: View's SELECT contains a variable or parameter * Error: `1352' SQLSTATE: `HY000' (`ER_VIEW_SELECT_TMPTABLE') Message: View's SELECT refers to a temporary table '%s' * Error: `1353' SQLSTATE: `HY000' (`ER_VIEW_WRONG_LIST') Message: View's SELECT and view's field list have different column counts * Error: `1354' SQLSTATE: `HY000' (`ER_WARN_VIEW_MERGE') Message: View merge algorithm can't be used here for now (assumed undefined algorithm) * Error: `1355' SQLSTATE: `HY000' (`ER_WARN_VIEW_WITHOUT_KEY') Message: View being updated does not have complete key of underlying table in it * Error: `1356' SQLSTATE: `HY000' (`ER_VIEW_INVALID') Message: View '%s.%s' references invalid table(s) or column(s) or function(s) or definer/invoker of view lack rights to use them * Error: `1357' SQLSTATE: `HY000' (`ER_SP_NO_DROP_SP') Message: Can't drop or alter a %s from within another stored routine * Error: `1358' SQLSTATE: `HY000' (`ER_SP_GOTO_IN_HNDLR') Message: GOTO is not allowed in a stored procedure handler * Error: `1359' SQLSTATE: `HY000' (`ER_TRG_ALREADY_EXISTS') Message: Trigger already exists * Error: `1360' SQLSTATE: `HY000' (`ER_TRG_DOES_NOT_EXIST') Message: Trigger does not exist * Error: `1361' SQLSTATE: `HY000' (`ER_TRG_ON_VIEW_OR_TEMP_TABLE') Message: Trigger's '%s' is view or temporary table * Error: `1362' SQLSTATE: `HY000' (`ER_TRG_CANT_CHANGE_ROW') Message: Updating of %s row is not allowed in %strigger * Error: `1363' SQLSTATE: `HY000' (`ER_TRG_NO_SUCH_ROW_IN_TRG') Message: There is no %s row in %s trigger * Error: `1364' SQLSTATE: `HY000' (`ER_NO_DEFAULT_FOR_FIELD') Message: Field '%s' doesn't have a default value * Error: `1365' SQLSTATE: `22012' (`ER_DIVISION_BY_ZERO') Message: Division by 0 * Error: `1366' SQLSTATE: `HY000' (`ER_TRUNCATED_WRONG_VALUE_FOR_FIELD') Message: Incorrect %s value: '%s' for column '%s' at row %ld * Error: `1367' SQLSTATE: `22007' (`ER_ILLEGAL_VALUE_FOR_TYPE') Message: Illegal %s '%s' value found during parsing * Error: `1368' SQLSTATE: `HY000' (`ER_VIEW_NONUPD_CHECK') Message: CHECK OPTION on non-updatable view '%s.%s' * Error: `1369' SQLSTATE: `HY000' (`ER_VIEW_CHECK_FAILED') Message: CHECK OPTION failed '%s.%s' * Error: `1370' SQLSTATE: `42000' (`ER_PROCACCESS_DENIED_ERROR') Message: %s command denied to user '%s'@'%s' for routine '%s' * Error: `1371' SQLSTATE: `HY000' (`ER_RELAY_LOG_FAIL') Message: Failed purging old relay logs: %s * Error: `1372' SQLSTATE: `HY000' (`ER_PASSWD_LENGTH') Message: Password hash should be a %d-digit hexadecimal number * Error: `1373' SQLSTATE: `HY000' (`ER_UNKNOWN_TARGET_BINLOG') Message: Target log not found in binlog index * Error: `1374' SQLSTATE: `HY000' (`ER_IO_ERR_LOG_INDEX_READ') Message: I/O error reading log index file * Error: `1375' SQLSTATE: `HY000' (`ER_BINLOG_PURGE_PROHIBITED') Message: Server configuration does not permit binlog purge * Error: `1376' SQLSTATE: `HY000' (`ER_FSEEK_FAIL') Message: Failed on fseek() * Error: `1377' SQLSTATE: `HY000' (`ER_BINLOG_PURGE_FATAL_ERR') Message: Fatal error during log purge * Error: `1378' SQLSTATE: `HY000' (`ER_LOG_IN_USE') Message: A purgeable log is in use, will not purge * Error: `1379' SQLSTATE: `HY000' (`ER_LOG_PURGE_UNKNOWN_ERR') Message: Unknown error during log purge * Error: `1380' SQLSTATE: `HY000' (`ER_RELAY_LOG_INIT') Message: Failed initializing relay log position: %s * Error: `1381' SQLSTATE: `HY000' (`ER_NO_BINARY_LOGGING') Message: You are not using binary logging * Error: `1382' SQLSTATE: `HY000' (`ER_RESERVED_SYNTAX') Message: The '%s' syntax is reserved for purposes internal to the MySQL server * Error: `1383' SQLSTATE: `HY000' (`ER_WSAS_FAILED') Message: WSAStartup Failed * Error: `1384' SQLSTATE: `HY000' (`ER_DIFF_GROUPS_PROC') Message: Can't handle procedures with different groups yet * Error: `1385' SQLSTATE: `HY000' (`ER_NO_GROUP_FOR_PROC') Message: Select must have a group with this procedure * Error: `1386' SQLSTATE: `HY000' (`ER_ORDER_WITH_PROC') Message: Can't use ORDER clause with this procedure * Error: `1387' SQLSTATE: `HY000' (`ER_LOGGING_PROHIBIT_CHANGING_OF') Message: Binary logging and replication forbid changing the global server %s * Error: `1388' SQLSTATE: `HY000' (`ER_NO_FILE_MAPPING') Message: Can't map file: %s, errno: %d * Error: `1389' SQLSTATE: `HY000' (`ER_WRONG_MAGIC') Message: Wrong magic in %s * Error: `1390' SQLSTATE: `HY000' (`ER_PS_MANY_PARAM') Message: Prepared statement contains too many placeholders * Error: `1391' SQLSTATE: `HY000' (`ER_KEY_PART_0') Message: Key part '%s' length cannot be 0 * Error: `1392' SQLSTATE: `HY000' (`ER_VIEW_CHECKSUM') Message: View text checksum failed * Error: `1393' SQLSTATE: `HY000' (`ER_VIEW_MULTIUPDATE') Message: Can not modify more than one base table through a join view '%s.%s' * Error: `1394' SQLSTATE: `HY000' (`ER_VIEW_NO_INSERT_FIELD_LIST') Message: Can not insert into join view '%s.%s' without fields list * Error: `1395' SQLSTATE: `HY000' (`ER_VIEW_DELETE_MERGE_VIEW') Message: Can not delete from join view '%s.%s' * Error: `1396' SQLSTATE: `HY000' (`ER_CANNOT_USER') Message: Operation %s failed for %s * Error: `1397' SQLSTATE: `XAE04' (`ER_XAER_NOTA') Message: XAER_NOTA: Unknown XID * Error: `1398' SQLSTATE: `XAE05' (`ER_XAER_INVAL') Message: XAER_INVAL: Invalid arguments (or unsupported command) * Error: `1399' SQLSTATE: `XAE07' (`ER_XAER_RMFAIL') Message: XAER_RMFAIL: The command cannot be executed when global transaction is in the %s state * Error: `1400' SQLSTATE: `XAE09' (`ER_XAER_OUTSIDE') Message: XAER_OUTSIDE: Some work is done outside global transaction * Error: `1401' SQLSTATE: `XAE03' (`ER_XAER_RMERR') Message: XAER_RMERR: Fatal error occurred in the transaction branch - check your data for consistency * Error: `1402' SQLSTATE: `XA100' (`ER_XA_RBROLLBACK') Message: XA_RBROLLBACK: Transaction branch was rolled back * Error: `1403' SQLSTATE: `42000' (`ER_NONEXISTING_PROC_GRANT') Message: There is no such grant defined for user '%s' on host '%s' on routine '%s' * Error: `1404' SQLSTATE: `HY000' (`ER_PROC_AUTO_GRANT_FAIL') Message: Failed to grant EXECUTE and ALTER ROUTINE privileges * Error: `1405' SQLSTATE: `HY000' (`ER_PROC_AUTO_REVOKE_FAIL') Message: Failed to revoke all privileges to dropped routine * Error: `1406' SQLSTATE: `22001' (`ER_DATA_TOO_LONG') Message: Data too long for column '%s' at row %ld * Error: `1407' SQLSTATE: `42000' (`ER_SP_BAD_SQLSTATE') Message: Bad SQLSTATE: '%s' * Error: `1408' SQLSTATE: `HY000' (`ER_STARTUP') Message: %s: ready for connections. Version: '%s' socket: '%s' port: %d %s * Error: `1409' SQLSTATE: `HY000' (`ER_LOAD_FROM_FIXED_SIZE_ROWS_TO_VAR') Message: Can't load value from file with fixed size rows to variable * Error: `1410' SQLSTATE: `42000' (`ER_CANT_CREATE_USER_WITH_GRANT') Message: You are not allowed to create a user with GRANT * Error: `1411' SQLSTATE: `HY000' (`ER_WRONG_VALUE_FOR_TYPE') Message: Incorrect %s value: '%s' for function %s * Error: `1412' SQLSTATE: `HY000' (`ER_TABLE_DEF_CHANGED') Message: Table definition has changed, please retry transaction * Error: `1413' SQLSTATE: `42000' (`ER_SP_DUP_HANDLER') Message: Duplicate handler declared in the same block * Error: `1414' SQLSTATE: `42000' (`ER_SP_NOT_VAR_ARG') Message: OUT or INOUT argument %d for routine %s is not a variable or NEW pseudo-variable in BEFORE trigger * Error: `1415' SQLSTATE: `0A000' (`ER_SP_NO_RETSET') Message: Not allowed to return a result set from a %s * Error: `1416' SQLSTATE: `22003' (`ER_CANT_CREATE_GEOMETRY_OBJECT') Message: Cannot get geometry object from data you send to the GEOMETRY field * Error: `1417' SQLSTATE: `HY000' (`ER_FAILED_ROUTINE_BREAK_BINLOG') Message: A routine failed and has neither NO SQL nor READS SQL DATA in its declaration and binary logging is enabled; if non-transactional tables were updated, the binary log will miss their changes * Error: `1418' SQLSTATE: `HY000' (`ER_BINLOG_UNSAFE_ROUTINE') Message: This function has none of DETERMINISTIC, NO SQL, or READS SQL DATA in its declaration and binary logging is enabled (you *might* want to use the less safe log_bin_trust_function_creators variable) * Error: `1419' SQLSTATE: `HY000' (`ER_BINLOG_CREATE_ROUTINE_NEED_SUPER') Message: You do not have the SUPER privilege and binary logging is enabled (you *might* want to use the less safe log_bin_trust_function_creators variable) * Error: `1420' SQLSTATE: `HY000' (`ER_EXEC_STMT_WITH_OPEN_CURSOR') Message: You can't execute a prepared statement which has an open cursor associated with it. Reset the statement to re-execute it. * Error: `1421' SQLSTATE: `HY000' (`ER_STMT_HAS_NO_OPEN_CURSOR') Message: The statement (%lu) has no open cursor. * Error: `1422' SQLSTATE: `HY000' (`ER_COMMIT_NOT_ALLOWED_IN_SF_OR_TRG') Message: Explicit or implicit commit is not allowed in stored function or trigger. * Error: `1423' SQLSTATE: `HY000' (`ER_NO_DEFAULT_FOR_VIEW_FIELD') Message: Field of view '%s.%s' underlying table doesn't have a default value * Error: `1424' SQLSTATE: `HY000' (`ER_SP_NO_RECURSION') Message: Recursive stored functions and triggers are not allowed. * Error: `1425' SQLSTATE: `42000' (`ER_TOO_BIG_SCALE') Message: Too big scale %d specified for column '%s'. Maximum is %lu. * Error: `1426' SQLSTATE: `42000' (`ER_TOO_BIG_PRECISION') Message: Too big precision %d specified for column '%s'. Maximum is %lu. * Error: `1427' SQLSTATE: `42000' (`ER_M_BIGGER_THAN_D') Message: For float(M,D), double(M,D) or decimal(M,D), M must be >= D (column '%s'). * Error: `1428' SQLSTATE: `HY000' (`ER_WRONG_LOCK_OF_SYSTEM_TABLE') Message: You can't combine write-locking of system tables with other tables or lock types * Error: `1429' SQLSTATE: `HY000' (`ER_CONNECT_TO_FOREIGN_DATA_SOURCE') Message: Unable to connect to foreign data source: %s * Error: `1430' SQLSTATE: `HY000' (`ER_QUERY_ON_FOREIGN_DATA_SOURCE') Message: There was a problem processing the query on the foreign data source. Data source error: %s * Error: `1431' SQLSTATE: `HY000' (`ER_FOREIGN_DATA_SOURCE_DOESNT_EXIST') Message: The foreign data source you are trying to reference does not exist. Data source error: %s * Error: `1432' SQLSTATE: `HY000' (`ER_FOREIGN_DATA_STRING_INVALID_CANT_CREATE') Message: Can't create federated table. The data source connection string '%s' is not in the correct format * Error: `1433' SQLSTATE: `HY000' (`ER_FOREIGN_DATA_STRING_INVALID') Message: The data source connection string '%s' is not in the correct format * Error: `1434' SQLSTATE: `HY000' (`ER_CANT_CREATE_FEDERATED_TABLE') Message: Can't create federated table. Foreign data src error: %s * Error: `1435' SQLSTATE: `HY000' (`ER_TRG_IN_WRONG_SCHEMA') Message: Trigger in wrong schema * Error: `1436' SQLSTATE: `HY000' (`ER_STACK_OVERRUN_NEED_MORE') Message: Thread stack overrun: %ld bytes used of a %ld byte stack, and %ld bytes needed. Use 'mysqld -O thread_stack=#' to specify a bigger stack. * Error: `1437' SQLSTATE: `42000' (`ER_TOO_LONG_BODY') Message: Routine body for '%s' is too long * Error: `1438' SQLSTATE: `HY000' (`ER_WARN_CANT_DROP_DEFAULT_KEYCACHE') Message: Cannot drop default keycache * Error: `1439' SQLSTATE: `42000' (`ER_TOO_BIG_DISPLAYWIDTH') Message: Display width out of range for column '%s' (max = %lu) * Error: `1440' SQLSTATE: `XAE08' (`ER_XAER_DUPID') Message: XAER_DUPID: The XID already exists * Error: `1441' SQLSTATE: `22008' (`ER_DATETIME_FUNCTION_OVERFLOW') Message: Datetime function: %s field overflow * Error: `1442' SQLSTATE: `HY000' (`ER_CANT_UPDATE_USED_TABLE_IN_SF_OR_TRG') Message: Can't update table '%s' in stored function/trigger because it is already used by statement which invoked this stored function/trigger. * Error: `1443' SQLSTATE: `HY000' (`ER_VIEW_PREVENT_UPDATE') Message: The definition of table '%s' prevents operation %s on table '%s'. * Error: `1444' SQLSTATE: `HY000' (`ER_PS_NO_RECURSION') Message: The prepared statement contains a stored routine call that refers to that same statement. It's not allowed to execute a prepared statement in such a recursive manner * Error: `1445' SQLSTATE: `HY000' (`ER_SP_CANT_SET_AUTOCOMMIT') Message: Not allowed to set autocommit from a stored function or trigger * Error: `1446' SQLSTATE: `HY000' (`ER_MALFORMED_DEFINER') Message: Definer is not fully qualified * Error: `1447' SQLSTATE: `HY000' (`ER_VIEW_FRM_NO_USER') Message: View '%s'.'%s' has no definer information (old table format). Current user is used as definer. Please recreate the view! * Error: `1448' SQLSTATE: `HY000' (`ER_VIEW_OTHER_USER') Message: You need the SUPER privilege for creation view with '%s'@'%s' definer * Error: `1449' SQLSTATE: `HY000' (`ER_NO_SUCH_USER') Message: The user specified as a definer ('%s'@'%s') does not exist * Error: `1450' SQLSTATE: `HY000' (`ER_FORBID_SCHEMA_CHANGE') Message: Changing schema from '%s' to '%s' is not allowed. * Error: `1451' SQLSTATE: `23000' (`ER_ROW_IS_REFERENCED_2') Message: Cannot delete or update a parent row: a foreign key constraint fails (%s) * Error: `1452' SQLSTATE: `23000' (`ER_NO_REFERENCED_ROW_2') Message: Cannot add or update a child row: a foreign key constraint fails (%s) * Error: `1453' SQLSTATE: `42000' (`ER_SP_BAD_VAR_SHADOW') Message: Variable '%s' must be quoted with `...`, or renamed * Error: `1454' SQLSTATE: `HY000' (`ER_TRG_NO_DEFINER') Message: No definer attribute for trigger '%s'.'%s'. The trigger will be activated under the authorization of the invoker, which may have insufficient privileges. Please recreate the trigger. * Error: `1455' SQLSTATE: `HY000' (`ER_OLD_FILE_FORMAT') Message: '%s' has an old format, you should re-create the '%s' object(s) * Error: `1456' SQLSTATE: `HY000' (`ER_SP_RECURSION_LIMIT') Message: Recursive limit %d (as set by the max_sp_recursion_depth variable) was exceeded for routine %s * Error: `1457' SQLSTATE: `HY000' (`ER_SP_PROC_TABLE_CORRUPT') Message: Failed to load routine %s. The table mysql.proc is missing, corrupt, or contains bad data (internal code %d) * Error: `1458' SQLSTATE: `42000' (`ER_SP_WRONG_NAME') Message: Incorrect routine name '%s' * Error: `1459' SQLSTATE: `HY000' (`ER_TABLE_NEEDS_UPGRADE') Message: Table upgrade required. Please do "REPAIR TABLE `%s`" or dump/reload to fix it! * Error: `1460' SQLSTATE: `42000' (`ER_SP_NO_AGGREGATE') Message: AGGREGATE is not supported for stored functions * Error: `1461' SQLSTATE: `42000' (`ER_MAX_PREPARED_STMT_COUNT_REACHED') Message: Can't create more than max_prepared_stmt_count statements (current value: %lu) * Error: `1462' SQLSTATE: `HY000' (`ER_VIEW_RECURSIVE') Message: `%s`.`%s` contains view recursion * Error: `1463' SQLSTATE: `42000' (`ER_NON_GROUPING_FIELD_USED') Message: non-grouping field '%s' is used in %s clause * Error: `1464' SQLSTATE: `HY000' (`ER_TABLE_CANT_HANDLE_SPKEYS') Message: The used table type doesn't support SPATIAL indexes * Error: `1465' SQLSTATE: `HY000' (`ER_NO_TRIGGERS_ON_SYSTEM_SCHEMA') Message: Triggers can not be created on system tables * Error: `1466' SQLSTATE: `HY000' (`ER_REMOVED_SPACES') Message: Leading spaces are removed from name '%s' * Error: `1467' SQLSTATE: `HY000' (`ER_AUTOINC_READ_FAILED') Message: Failed to read auto-increment value from storage engine * Error: `1468' SQLSTATE: `HY000' (`ER_USERNAME') Message: user name * Error: `1469' SQLSTATE: `HY000' (`ER_HOSTNAME') Message: host name * Error: `1470' SQLSTATE: `HY000' (`ER_WRONG_STRING_LENGTH') Message: String '%s' is too long for %s (should be no longer than %d) * Error: `1471' SQLSTATE: `HY000' (`ER_NON_INSERTABLE_TABLE') Message: The target table %s of the %s is not insertable-into * Error: `1472' SQLSTATE: `HY000' (`ER_ADMIN_WRONG_MRG_TABLE') Message: Table '%s' is differently defined or of non-MyISAM type or doesn't exist * Error: `1473' SQLSTATE: `HY000' (`ER_TOO_HIGH_LEVEL_OF_NESTING_FOR_SELECT') Message: Too high level of nesting for select * Error: `1474' SQLSTATE: `HY000' (`ER_NAME_BECOMES_EMPTY') Message: Name '%s' has become " * Error: `1475' SQLSTATE: `HY000' (`ER_AMBIGUOUS_FIELD_TERM') Message: First character of the FIELDS TERMINATED string is ambiguous; please use non-optional and non-empty FIELDS ENCLOSED BY * Error: `1476' SQLSTATE: `HY000' (`ER_FOREIGN_SERVER_EXISTS') Message: The foreign server, %s, you are trying to create already exists. * Error: `1477' SQLSTATE: `HY000' (`ER_FOREIGN_SERVER_DOESNT_EXIST') Message: The foreign server name you are trying to reference does not exist. Data source error: %s * Error: `1478' SQLSTATE: `HY000' (`ER_ILLEGAL_HA_CREATE_OPTION') Message: Table storage engine '%s' does not support the create option '%s' * Error: `1479' SQLSTATE: `HY000' (`ER_PARTITION_REQUIRES_VALUES_ERROR') Message: Syntax error: %s PARTITIONING requires definition of VALUES %s for each partition * Error: `1480' SQLSTATE: `HY000' (`ER_PARTITION_WRONG_VALUES_ERROR') Message: Only %s PARTITIONING can use VALUES %s in partition definition * Error: `1481' SQLSTATE: `HY000' (`ER_PARTITION_MAXVALUE_ERROR') Message: MAXVALUE can only be used in last partition definition * Error: `1482' SQLSTATE: `HY000' (`ER_PARTITION_SUBPARTITION_ERROR') Message: Subpartitions can only be hash partitions and by key * Error: `1483' SQLSTATE: `HY000' (`ER_PARTITION_SUBPART_MIX_ERROR') Message: Must define subpartitions on all partitions if on one partition * Error: `1484' SQLSTATE: `HY000' (`ER_PARTITION_WRONG_NO_PART_ERROR') Message: Wrong number of partitions defined, mismatch with previous setting * Error: `1485' SQLSTATE: `HY000' (`ER_PARTITION_WRONG_NO_SUBPART_ERROR') Message: Wrong number of subpartitions defined, mismatch with previous setting * Error: `1486' SQLSTATE: `HY000' (`ER_WRONG_EXPR_IN_PARTITION_FUNC_ERROR') Message: Constant, random or timezone-dependent expressions in (sub)partitioning function are not allowed * Error: `1487' SQLSTATE: `HY000' (`ER_NO_CONST_EXPR_IN_RANGE_OR_LIST_ERROR') Message: Expression in RANGE/LIST VALUES must be constant * Error: `1488' SQLSTATE: `HY000' (`ER_FIELD_NOT_FOUND_PART_ERROR') Message: Field in list of fields for partition function not found in table * Error: `1489' SQLSTATE: `HY000' (`ER_LIST_OF_FIELDS_ONLY_IN_HASH_ERROR') Message: List of fields is only allowed in KEY partitions * Error: `1490' SQLSTATE: `HY000' (`ER_INCONSISTENT_PARTITION_INFO_ERROR') Message: The partition info in the frm file is not consistent with what can be written into the frm file * Error: `1491' SQLSTATE: `HY000' (`ER_PARTITION_FUNC_NOT_ALLOWED_ERROR') Message: The %s function returns the wrong type * Error: `1492' SQLSTATE: `HY000' (`ER_PARTITIONS_MUST_BE_DEFINED_ERROR') Message: For %s partitions each partition must be defined * Error: `1493' SQLSTATE: `HY000' (`ER_RANGE_NOT_INCREASING_ERROR') Message: VALUES LESS THAN value must be strictly increasing for each partition * Error: `1494' SQLSTATE: `HY000' (`ER_INCONSISTENT_TYPE_OF_FUNCTIONS_ERROR') Message: VALUES value must be of same type as partition function * Error: `1495' SQLSTATE: `HY000' (`ER_MULTIPLE_DEF_CONST_IN_LIST_PART_ERROR') Message: Multiple definition of same constant in list partitioning * Error: `1496' SQLSTATE: `HY000' (`ER_PARTITION_ENTRY_ERROR') Message: Partitioning can not be used stand-alone in query * Error: `1497' SQLSTATE: `HY000' (`ER_MIX_HANDLER_ERROR') Message: The mix of handlers in the partitions is not allowed in this version of MySQL * Error: `1498' SQLSTATE: `HY000' (`ER_PARTITION_NOT_DEFINED_ERROR') Message: For the partitioned engine it is necessary to define all %s * Error: `1499' SQLSTATE: `HY000' (`ER_TOO_MANY_PARTITIONS_ERROR') Message: Too many partitions (including subpartitions) were defined * Error: `1500' SQLSTATE: `HY000' (`ER_SUBPARTITION_ERROR') Message: It is only possible to mix RANGE/LIST partitioning with HASH/KEY partitioning for subpartitioning * Error: `1501' SQLSTATE: `HY000' (`ER_CANT_CREATE_HANDLER_FILE') Message: Failed to create specific handler file * Error: `1502' SQLSTATE: `HY000' (`ER_BLOB_FIELD_IN_PART_FUNC_ERROR') Message: A BLOB field is not allowed in partition function * Error: `1503' SQLSTATE: `HY000' (`ER_UNIQUE_KEY_NEED_ALL_FIELDS_IN_PF') Message: A %s must include all columns in the table's partitioning function * Error: `1504' SQLSTATE: `HY000' (`ER_NO_PARTS_ERROR') Message: Number of %s = 0 is not an allowed value * Error: `1505' SQLSTATE: `HY000' (`ER_PARTITION_MGMT_ON_NONPARTITIONED') Message: Partition management on a not partitioned table is not possible * Error: `1506' SQLSTATE: `HY000' (`ER_FOREIGN_KEY_ON_PARTITIONED') Message: Foreign key clause is not yet supported in conjunction with partitioning * Error: `1507' SQLSTATE: `HY000' (`ER_DROP_PARTITION_NON_EXISTENT') Message: Error in list of partitions to %s * Error: `1508' SQLSTATE: `HY000' (`ER_DROP_LAST_PARTITION') Message: Cannot remove all partitions, use DROP TABLE instead * Error: `1509' SQLSTATE: `HY000' (`ER_COALESCE_ONLY_ON_HASH_PARTITION') Message: COALESCE PARTITION can only be used on HASH/KEY partitions * Error: `1510' SQLSTATE: `HY000' (`ER_REORG_HASH_ONLY_ON_SAME_NO') Message: REORGANIZE PARTITION can only be used to reorganize partitions not to change their numbers * Error: `1511' SQLSTATE: `HY000' (`ER_REORG_NO_PARAM_ERROR') Message: REORGANIZE PARTITION without parameters can only be used on auto-partitioned tables using HASH PARTITIONs * Error: `1512' SQLSTATE: `HY000' (`ER_ONLY_ON_RANGE_LIST_PARTITION') Message: %s PARTITION can only be used on RANGE/LIST partitions * Error: `1513' SQLSTATE: `HY000' (`ER_ADD_PARTITION_SUBPART_ERROR') Message: Trying to Add partition(s) with wrong number of subpartitions * Error: `1514' SQLSTATE: `HY000' (`ER_ADD_PARTITION_NO_NEW_PARTITION') Message: At least one partition must be added * Error: `1515' SQLSTATE: `HY000' (`ER_COALESCE_PARTITION_NO_PARTITION') Message: At least one partition must be coalesced * Error: `1516' SQLSTATE: `HY000' (`ER_REORG_PARTITION_NOT_EXIST') Message: More partitions to reorganize than there are partitions * Error: `1517' SQLSTATE: `HY000' (`ER_SAME_NAME_PARTITION') Message: Duplicate partition name %s * Error: `1518' SQLSTATE: `HY000' (`ER_NO_BINLOG_ERROR') Message: It is not allowed to shut off binlog on this command * Error: `1519' SQLSTATE: `HY000' (`ER_CONSECUTIVE_REORG_PARTITIONS') Message: When reorganizing a set of partitions they must be in consecutive order * Error: `1520' SQLSTATE: `HY000' (`ER_REORG_OUTSIDE_RANGE') Message: Reorganize of range partitions cannot change total ranges except for last partition where it can extend the range * Error: `1521' SQLSTATE: `HY000' (`ER_PARTITION_FUNCTION_FAILURE') Message: Partition function not supported in this version for this handler * Error: `1522' SQLSTATE: `HY000' (`ER_PART_STATE_ERROR') Message: Partition state cannot be defined from CREATE/ALTER TABLE * Error: `1523' SQLSTATE: `HY000' (`ER_LIMITED_PART_RANGE') Message: The %s handler only supports 32 bit integers in VALUES * Error: `1524' SQLSTATE: `HY000' (`ER_PLUGIN_IS_NOT_LOADED') Message: Plugin '%s' is not loaded * Error: `1525' SQLSTATE: `HY000' (`ER_WRONG_VALUE') Message: Incorrect %s value: '%s' * Error: `1526' SQLSTATE: `HY000' (`ER_NO_PARTITION_FOR_GIVEN_VALUE') Message: Table has no partition for value %s * Error: `1527' SQLSTATE: `HY000' (`ER_FILEGROUP_OPTION_ONLY_ONCE') Message: It is not allowed to specify %s more than once * Error: `1528' SQLSTATE: `HY000' (`ER_CREATE_FILEGROUP_FAILED') Message: Failed to create %s * Error: `1529' SQLSTATE: `HY000' (`ER_DROP_FILEGROUP_FAILED') Message: Failed to drop %s * Error: `1530' SQLSTATE: `HY000' (`ER_TABLESPACE_AUTO_EXTEND_ERROR') Message: The handler doesn't support autoextend of tablespaces * Error: `1531' SQLSTATE: `HY000' (`ER_WRONG_SIZE_NUMBER') Message: A size parameter was incorrectly specified, either number or on the form 10M * Error: `1532' SQLSTATE: `HY000' (`ER_SIZE_OVERFLOW_ERROR') Message: The size number was correct but we don't allow the digit part to be more than 2 billion * Error: `1533' SQLSTATE: `HY000' (`ER_ALTER_FILEGROUP_FAILED') Message: Failed to alter: %s * Error: `1534' SQLSTATE: `HY000' (`ER_BINLOG_ROW_LOGGING_FAILED') Message: Writing one row to the row-based binary log failed * Error: `1535' SQLSTATE: `HY000' (`ER_BINLOG_ROW_WRONG_TABLE_DEF') Message: Table definition on master and slave does not match: %s * Error: `1536' SQLSTATE: `HY000' (`ER_BINLOG_ROW_RBR_TO_SBR') Message: Slave running with -log-slave-updates must use row-based binary logging to be able to replicate row-based binary log events * Error: `1537' SQLSTATE: `HY000' (`ER_EVENT_ALREADY_EXISTS') Message: Event '%s' already exists * Error: `1538' SQLSTATE: `HY000' (`ER_EVENT_STORE_FAILED') Message: Failed to store event %s. Error code %d from storage engine. * Error: `1539' SQLSTATE: `HY000' (`ER_EVENT_DOES_NOT_EXIST') Message: Unknown event '%s' * Error: `1540' SQLSTATE: `HY000' (`ER_EVENT_CANT_ALTER') Message: Failed to alter event '%s' * Error: `1541' SQLSTATE: `HY000' (`ER_EVENT_DROP_FAILED') Message: Failed to drop %s * Error: `1542' SQLSTATE: `HY000' (`ER_EVENT_INTERVAL_NOT_POSITIVE_OR_TOO_BIG') Message: INTERVAL is either not positive or too big * Error: `1543' SQLSTATE: `HY000' (`ER_EVENT_ENDS_BEFORE_STARTS') Message: ENDS is either invalid or before STARTS * Error: `1544' SQLSTATE: `HY000' (`ER_EVENT_EXEC_TIME_IN_THE_PAST') Message: Event execution time is in the past. Event has been disabled * Error: `1545' SQLSTATE: `HY000' (`ER_EVENT_OPEN_TABLE_FAILED') Message: Failed to open mysql.event * Error: `1546' SQLSTATE: `HY000' (`ER_EVENT_NEITHER_M_EXPR_NOR_M_AT') Message: No datetime expression provided * Error: `1547' SQLSTATE: `HY000' (`ER_COL_COUNT_DOESNT_MATCH_CORRUPTED') Message: Column count of mysql.%s is wrong. Expected %d, found %d. The table is probably corrupted * Error: `1548' SQLSTATE: `HY000' (`ER_CANNOT_LOAD_FROM_TABLE') Message: Cannot load from mysql.%s. The table is probably corrupted * Error: `1549' SQLSTATE: `HY000' (`ER_EVENT_CANNOT_DELETE') Message: Failed to delete the event from mysql.event * Error: `1550' SQLSTATE: `HY000' (`ER_EVENT_COMPILE_ERROR') Message: Error during compilation of event's body * Error: `1551' SQLSTATE: `HY000' (`ER_EVENT_SAME_NAME') Message: Same old and new event name * Error: `1552' SQLSTATE: `HY000' (`ER_EVENT_DATA_TOO_LONG') Message: Data for column '%s' too long * Error: `1553' SQLSTATE: `HY000' (`ER_DROP_INDEX_FK') Message: Cannot drop index '%s': needed in a foreign key constraint * Error: `1554' SQLSTATE: `HY000' (`ER_WARN_DEPRECATED_SYNTAX_WITH_VER') Message: The syntax '%s' is deprecated and will be removed in MySQL %s. Please use %s instead * Error: `1555' SQLSTATE: `HY000' (`ER_CANT_WRITE_LOCK_LOG_TABLE') Message: You can't write-lock a log table. Only read access is possible * Error: `1556' SQLSTATE: `HY000' (`ER_CANT_LOCK_LOG_TABLE') Message: You can't use locks with log tables. * Error: `1557' SQLSTATE: `23000' (`ER_FOREIGN_DUPLICATE_KEY') Message: Upholding foreign key constraints for table '%s', entry '%s', key %d would lead to a duplicate entry * Error: `1558' SQLSTATE: `HY000' (`ER_COL_COUNT_DOESNT_MATCH_PLEASE_UPDATE') Message: Column count of mysql.%s is wrong. Expected %d, found %d. Created with MySQL %d, now running %d. Please use mysql_upgrade to fix this error. * Error: `1559' SQLSTATE: `HY000' (`ER_TEMP_TABLE_PREVENTS_SWITCH_OUT_OF_RBR') Message: Cannot switch out of the row-based binary log format when the session has open temporary tables * Error: `1560' SQLSTATE: `HY000' (`ER_STORED_FUNCTION_PREVENTS_SWITCH_BINLOG_FORMAT') Message: Cannot change the binary logging format inside a stored function or trigger * Error: `1561' SQLSTATE: `HY000' (`ER_NDB_CANT_SWITCH_BINLOG_FORMAT') Message: The NDB cluster engine does not support changing the binlog format on the fly yet * Error: `1562' SQLSTATE: `HY000' (`ER_PARTITION_NO_TEMPORARY') Message: Cannot create temporary table with partitions * Error: `1563' SQLSTATE: `HY000' (`ER_PARTITION_CONST_DOMAIN_ERROR') Message: Partition constant is out of partition function domain * Error: `1564' SQLSTATE: `HY000' (`ER_PARTITION_FUNCTION_IS_NOT_ALLOWED') Message: This partition function is not allowed * Error: `1565' SQLSTATE: `HY000' (`ER_DDL_LOG_ERROR') Message: Error in DDL log * Error: `1566' SQLSTATE: `HY000' (`ER_NULL_IN_VALUES_LESS_THAN') Message: Not allowed to use NULL value in VALUES LESS THAN * Error: `1567' SQLSTATE: `HY000' (`ER_WRONG_PARTITION_NAME') Message: Incorrect partition name * Error: `1568' SQLSTATE: `25001' (`ER_CANT_CHANGE_TX_ISOLATION') Message: Transaction isolation level can't be changed while a transaction is in progress * Error: `1569' SQLSTATE: `HY000' (`ER_DUP_ENTRY_AUTOINCREMENT_CASE') Message: ALTER TABLE causes auto_increment resequencing, resulting in duplicate entry '%s' for key '%s' * Error: `1570' SQLSTATE: `HY000' (`ER_EVENT_MODIFY_QUEUE_ERROR') Message: Internal scheduler error %d * Error: `1571' SQLSTATE: `HY000' (`ER_EVENT_SET_VAR_ERROR') Message: Error during starting/stopping of the scheduler. Error code %u * Error: `1572' SQLSTATE: `HY000' (`ER_PARTITION_MERGE_ERROR') Message: Engine cannot be used in partitioned tables * Error: `1573' SQLSTATE: `HY000' (`ER_CANT_ACTIVATE_LOG') Message: Cannot activate '%s' log * Error: `1574' SQLSTATE: `HY000' (`ER_RBR_NOT_AVAILABLE') Message: The server was not built with row-based replication * Error: `1575' SQLSTATE: `HY000' (`ER_BASE64_DECODE_ERROR') Message: Decoding of base64 string failed * Error: `1576' SQLSTATE: `HY000' (`ER_EVENT_RECURSION_FORBIDDEN') Message: Recursion of EVENT DDL statements is forbidden when body is present * Error: `1577' SQLSTATE: `HY000' (`ER_EVENTS_DB_ERROR') Message: Cannot proceed because system tables used by Event Scheduler were found damaged at server start * Error: `1578' SQLSTATE: `HY000' (`ER_ONLY_INTEGERS_ALLOWED') Message: Only integers allowed as number here * Error: `1579' SQLSTATE: `HY000' (`ER_UNSUPORTED_LOG_ENGINE') Message: This storage engine cannot be used for log tables" * Error: `1580' SQLSTATE: `HY000' (`ER_BAD_LOG_STATEMENT') Message: You cannot '%s' a log table if logging is enabled * Error: `1581' SQLSTATE: `HY000' (`ER_CANT_RENAME_LOG_TABLE') Message: Cannot rename '%s'. When logging enabled, rename to/from log table must rename two tables: the log table to an archive table and another table back to '%s' * Error: `1582' SQLSTATE: `42000' (`ER_WRONG_PARAMCOUNT_TO_NATIVE_FCT') Message: Incorrect parameter count in the call to native function '%s' * Error: `1583' SQLSTATE: `42000' (`ER_WRONG_PARAMETERS_TO_NATIVE_FCT') Message: Incorrect parameters in the call to native function '%s' * Error: `1584' SQLSTATE: `42000' (`ER_WRONG_PARAMETERS_TO_STORED_FCT') Message: Incorrect parameters in the call to stored function '%s' * Error: `1585' SQLSTATE: `HY000' (`ER_NATIVE_FCT_NAME_COLLISION') Message: This function '%s' has the same name as a native function * Error: `1586' SQLSTATE: `23000' (`ER_DUP_ENTRY_WITH_KEY_NAME') Message: Duplicate entry '%s' for key '%s' * Error: `1587' SQLSTATE: `HY000' (`ER_BINLOG_PURGE_EMFILE') Message: Too many files opened, please execute the command again * Error: `1588' SQLSTATE: `HY000' (`ER_EVENT_CANNOT_CREATE_IN_THE_PAST') Message: Event execution time is in the past and ON COMPLETION NOT PRESERVE is set. The event was dropped immediately after creation. * Error: `1589' SQLSTATE: `HY000' (`ER_EVENT_CANNOT_ALTER_IN_THE_PAST') Message: Event execution time is in the past and ON COMPLETION NOT PRESERVE is set. The event was dropped immediately after creation. * Error: `1590' SQLSTATE: `HY000' (`ER_SLAVE_INCIDENT') Message: The incident %s occured on the master. Message: %s * Error: `1591' SQLSTATE: `HY000' (`ER_NO_PARTITION_FOR_GIVEN_VALUE_SILENT') Message: Table has no partition for some existing values * Error: `1592' SQLSTATE: `HY000' (`ER_BINLOG_UNSAFE_STATEMENT') Message: Statement may not be safe to log in statement format. * Error: `1593' SQLSTATE: `HY000' (`ER_SLAVE_FATAL_ERROR') Message: Fatal error: %s * Error: `1594' SQLSTATE: `HY000' (`ER_SLAVE_RELAY_LOG_READ_FAILURE') Message: Relay log read failure: %s * Error: `1595' SQLSTATE: `HY000' (`ER_SLAVE_RELAY_LOG_WRITE_FAILURE') Message: Relay log write failure: %s * Error: `1596' SQLSTATE: `HY000' (`ER_SLAVE_CREATE_EVENT_FAILURE') Message: Failed to create %s * Error: `1597' SQLSTATE: `HY000' (`ER_SLAVE_MASTER_COM_FAILURE') Message: Master command %s failed: %s * Error: `1598' SQLSTATE: `HY000' (`ER_BINLOG_LOGGING_IMPOSSIBLE') Message: Binary logging not possible. Message: %s * Error: `1599' SQLSTATE: `HY000' (`ER_VIEW_NO_CREATION_CTX') Message: View `%s`.`%s` has no creation context * Error: `1600' SQLSTATE: `HY000' (`ER_VIEW_INVALID_CREATION_CTX') Message: Creation context of view `%s`.`%s' is invalid * Error: `1601' SQLSTATE: `HY000' (`ER_SR_INVALID_CREATION_CTX') Message: Creation context of stored routine `%s`.`%s` is invalid * Error: `1602' SQLSTATE: `HY000' (`ER_TRG_CORRUPTED_FILE') Message: Corrupted TRG file for table `%s`.`%s` * Error: `1603' SQLSTATE: `HY000' (`ER_TRG_NO_CREATION_CTX') Message: Triggers for table `%s`.`%s` have no creation context * Error: `1604' SQLSTATE: `HY000' (`ER_TRG_INVALID_CREATION_CTX') Message: Trigger creation context of table `%s`.`%s` is invalid * Error: `1605' SQLSTATE: `HY000' (`ER_EVENT_INVALID_CREATION_CTX') Message: Creation context of event `%s`.`%s` is invalid * Error: `1606' SQLSTATE: `HY000' (`ER_TRG_CANT_OPEN_TABLE') Message: Cannot open table for trigger `%s`.`%s` * Error: `1607' SQLSTATE: `HY000' (`ER_CANT_CREATE_SROUTINE') Message: Cannot create stored routine `%s`. Check warnings * Error: `1608' SQLSTATE: `HY000' (`ER_SLAVE_AMBIGOUS_EXEC_MODE') Message: Ambiguous slave modes combination. %s * Error: `1609' SQLSTATE: `HY000' (`ER_NO_FORMAT_DESCRIPTION_EVENT_BEFORE_BINLOG_STATEMENT') Message: The BINLOG statement of type `%s` was not preceded by a format description BINLOG statement. * Error: `1610' SQLSTATE: `HY000' (`ER_SLAVE_CORRUPT_EVENT') Message: Corrupted replication event was detected * Error: `1611' SQLSTATE: `HY000' (`ER_LOAD_DATA_INVALID_COLUMN') Message: Invalid column reference (%s) in LOAD DATA * Error: `1612' SQLSTATE: `HY000' (`ER_LOG_PURGE_NO_FILE') Message: Being purged log %s was not found * Error: `1613' SQLSTATE: `XA106' (`ER_XA_RBTIMEOUT') Message: XA_RBTIMEOUT: Transaction branch was rolled back: took too long * Error: `1614' SQLSTATE: `XA102' (`ER_XA_RBDEADLOCK') Message: XA_RBDEADLOCK: Transaction branch was rolled back: deadlock was detected * Error: `1615' SQLSTATE: `HY000' (`ER_NEED_REPREPARE') Message: Prepared statement needs to be re-prepared * Error: `1616' SQLSTATE: `HY000' (`ER_DELAYED_NOT_SUPPORTED') Message: DELAYED option not supported for table '%s' * Error: `1617' SQLSTATE: `HY000' (`WARN_NO_MASTER_INFO') Message: The master info structure does not exist * Error: `1618' SQLSTATE: `HY000' (`WARN_OPTION_IGNORED') Message: <%s> option ignored * Error: `1619' SQLSTATE: `HY000' (`WARN_PLUGIN_DELETE_BUILTIN') Message: Built-in plugins cannot be deleted * Error: `1620' SQLSTATE: `HY000' (`WARN_PLUGIN_BUSY') Message: Plugin is busy and will be uninstalled on shutdown * Error: `1621' SQLSTATE: `HY000' (`ER_VARIABLE_IS_READONLY') Message: %s variable '%s' is read-only. Use SET %s to assign the value * Error: `1622' SQLSTATE: `HY000' (`ER_WARN_ENGINE_TRANSACTION_ROLLBACK') Message: Storage engine %s does not support rollback for this statement. Transaction rolled back and must be restarted * Error: `1623' SQLSTATE: `HY000' (`ER_SLAVE_HEARTBEAT_FAILURE') Message: Unexpected master's heartbeat data: %s * Error: `1624' SQLSTATE: `HY000' (`ER_SLAVE_HEARTBEAT_VALUE_OUT_OF_RANGE') Message: The requested value for the heartbeat period %s %s * Error: `1625' SQLSTATE: `HY000' (`ER_NDB_REPLICATION_SCHEMA_ERROR') Message: Bad schema for mysql.ndb_replication table. Message: %s * Error: `1626' SQLSTATE: `HY000' (`ER_CONFLICT_FN_PARSE_ERROR') Message: Error in parsing conflict function. Message: %s * Error: `1627' SQLSTATE: `HY000' (`ER_EXCEPTIONS_WRITE_ERROR') Message: Write to exceptions table failed. Message: %s" * Error: `1628' SQLSTATE: `HY000' (`ER_TOO_LONG_TABLE_COMMENT') Message: Comment for table '%s' is too long (max = %lu) * Error: `1629' SQLSTATE: `HY000' (`ER_TOO_LONG_FIELD_COMMENT') Message: Comment for field '%s' is too long (max = %lu) * Error: `1630' SQLSTATE: `42000' (`ER_FUNC_INEXISTENT_NAME_COLLISION') Message: FUNCTION %s does not exist. Check the 'Function Name Parsing and Resolution' section in the Reference Manual * Error: `1631' SQLSTATE: `HY000' (`ER_DATABASE_NAME') Message: Database * Error: `1632' SQLSTATE: `HY000' (`ER_TABLE_NAME') Message: Table * Error: `1633' SQLSTATE: `HY000' (`ER_PARTITION_NAME') Message: Partition * Error: `1634' SQLSTATE: `HY000' (`ER_SUBPARTITION_NAME') Message: Subpartition * Error: `1635' SQLSTATE: `HY000' (`ER_TEMPORARY_NAME') Message: Temporary * Error: `1636' SQLSTATE: `HY000' (`ER_RENAMED_NAME') Message: Renamed * Error: `1637' SQLSTATE: `HY000' (`ER_TOO_MANY_CONCURRENT_TRXS') Message: Too many active concurrent transactions * Error: `1638' SQLSTATE: `HY000' (`WARN_NON_ASCII_SEPARATOR_NOT_IMPLEMENTED') Message: Non-ASCII separator arguments are not fully supported * Error: `1639' SQLSTATE: `HY000' (`ER_DEBUG_SYNC_TIMEOUT') Message: debug sync point wait timed out * Error: `1640' SQLSTATE: `HY000' (`ER_DEBUG_SYNC_HIT_LIMIT') Message: debug sync point hit limit reached  File: manual.info, Node: error-messages-client, Next: problems, Prev: error-messages-server, Up: error-handling C.4 Client Error Codes and Messages =================================== Client error information comes from the following source files: * The Error values and the symbols in parentheses correspond to definitions in the `include/errmsg.h' MySQL source file. * The Message values correspond to the error messages that are listed in the `libmysql/errmsg.c' file. `%d' and `%s' represent numbers and strings, respectively, that are substituted into the messages when they are displayed. Because updates are frequent, it is possible that those files will contain additional error information not listed here. * Error: `2000' (`CR_UNKNOWN_ERROR') Message: Unknown MySQL error * Error: `2001' (`CR_SOCKET_CREATE_ERROR') Message: Can't create UNIX socket (%d) * Error: `2002' (`CR_CONNECTION_ERROR') Message: Can't connect to local MySQL server through socket '%s' (%d) * Error: `2003' (`CR_CONN_HOST_ERROR') Message: Can't connect to MySQL server on '%s' (%d) * Error: `2004' (`CR_IPSOCK_ERROR') Message: Can't create TCP/IP socket (%d) * Error: `2005' (`CR_UNKNOWN_HOST') Message: Unknown MySQL server host '%s' (%d) * Error: `2006' (`CR_SERVER_GONE_ERROR') Message: MySQL server has gone away * Error: `2007' (`CR_VERSION_ERROR') Message: Protocol mismatch; server version = %d, client version = %d * Error: `2008' (`CR_OUT_OF_MEMORY') Message: MySQL client ran out of memory * Error: `2009' (`CR_WRONG_HOST_INFO') Message: Wrong host info * Error: `2010' (`CR_LOCALHOST_CONNECTION') Message: Localhost via UNIX socket * Error: `2011' (`CR_TCP_CONNECTION') Message: %s via TCP/IP * Error: `2012' (`CR_SERVER_HANDSHAKE_ERR') Message: Error in server handshake * Error: `2013' (`CR_SERVER_LOST') Message: Lost connection to MySQL server during query * Error: `2014' (`CR_COMMANDS_OUT_OF_SYNC') Message: Commands out of sync; you can't run this command now * Error: `2015' (`CR_NAMEDPIPE_CONNECTION') Message: Named pipe: %s * Error: `2016' (`CR_NAMEDPIPEWAIT_ERROR') Message: Can't wait for named pipe to host: %s pipe: %s (%lu) * Error: `2017' (`CR_NAMEDPIPEOPEN_ERROR') Message: Can't open named pipe to host: %s pipe: %s (%lu) * Error: `2018' (`CR_NAMEDPIPESETSTATE_ERROR') Message: Can't set state of named pipe to host: %s pipe: %s (%lu) * Error: `2019' (`CR_CANT_READ_CHARSET') Message: Can't initialize character set %s (path: %s) * Error: `2020' (`CR_NET_PACKET_TOO_LARGE') Message: Got packet bigger than 'max_allowed_packet' bytes * Error: `2021' (`CR_EMBEDDED_CONNECTION') Message: Embedded server * Error: `2022' (`CR_PROBE_SLAVE_STATUS') Message: Error on SHOW SLAVE STATUS: * Error: `2023' (`CR_PROBE_SLAVE_HOSTS') Message: Error on SHOW SLAVE HOSTS: * Error: `2024' (`CR_PROBE_SLAVE_CONNECT') Message: Error connecting to slave: * Error: `2025' (`CR_PROBE_MASTER_CONNECT') Message: Error connecting to master: * Error: `2026' (`CR_SSL_CONNECTION_ERROR') Message: SSL connection error * Error: `2027' (`CR_MALFORMED_PACKET') Message: Malformed packet * Error: `2028' (`CR_WRONG_LICENSE') Message: This client library is licensed only for use with MySQL servers having '%s' license * Error: `2029' (`CR_NULL_POINTER') Message: Invalid use of null pointer * Error: `2030' (`CR_NO_PREPARE_STMT') Message: Statement not prepared * Error: `2031' (`CR_PARAMS_NOT_BOUND') Message: No data supplied for parameters in prepared statement * Error: `2032' (`CR_DATA_TRUNCATED') Message: Data truncated * Error: `2033' (`CR_NO_PARAMETERS_EXISTS') Message: No parameters exist in the statement * Error: `2034' (`CR_INVALID_PARAMETER_NO') Message: Invalid parameter number * Error: `2035' (`CR_INVALID_BUFFER_USE') Message: Can't send long data for non-string/non-binary data types (parameter: %d) * Error: `2036' (`CR_UNSUPPORTED_PARAM_TYPE') Message: Using unsupported buffer type: %d (parameter: %d) * Error: `2037' (`CR_SHARED_MEMORY_CONNECTION') Message: Shared memory: %s * Error: `2038' (`CR_SHARED_MEMORY_CONNECT_REQUEST_ERROR') Message: Can't open shared memory; client could not create request event (%lu) * Error: `2039' (`CR_SHARED_MEMORY_CONNECT_ANSWER_ERROR') Message: Can't open shared memory; no answer event received from server (%lu) * Error: `2040' (`CR_SHARED_MEMORY_CONNECT_FILE_MAP_ERROR') Message: Can't open shared memory; server could not allocate file mapping (%lu) * Error: `2041' (`CR_SHARED_MEMORY_CONNECT_MAP_ERROR') Message: Can't open shared memory; server could not get pointer to file mapping (%lu) * Error: `2042' (`CR_SHARED_MEMORY_FILE_MAP_ERROR') Message: Can't open shared memory; client could not allocate file mapping (%lu) * Error: `2043' (`CR_SHARED_MEMORY_MAP_ERROR') Message: Can't open shared memory; client could not get pointer to file mapping (%lu) * Error: `2044' (`CR_SHARED_MEMORY_EVENT_ERROR') Message: Can't open shared memory; client could not create %s event (%lu) * Error: `2045' (`CR_SHARED_MEMORY_CONNECT_ABANDONED_ERROR') Message: Can't open shared memory; no answer from server (%lu) * Error: `2046' (`CR_SHARED_MEMORY_CONNECT_SET_ERROR') Message: Can't open shared memory; cannot send request event to server (%lu) * Error: `2047' (`CR_CONN_UNKNOW_PROTOCOL') Message: Wrong or unknown protocol * Error: `2048' (`CR_INVALID_CONN_HANDLE') Message: Invalid connection handle * Error: `2049' (`CR_SECURE_AUTH') Message: Connection using old (pre-4.1.1) authentication protocol refused (client option 'secure_auth' enabled) * Error: `2050' (`CR_FETCH_CANCELED') Message: Row retrieval was canceled by mysql_stmt_close() call * Error: `2051' (`CR_NO_DATA') Message: Attempt to read column without prior row fetch * Error: `2052' (`CR_NO_STMT_METADATA') Message: Prepared statement contains no metadata * Error: `2053' (`CR_NO_RESULT_SET') Message: Attempt to read a row while there is no result set associated with the statement * Error: `2054' (`CR_NOT_IMPLEMENTED') Message: This feature is not implemented yet * Error: `2055' (`CR_SERVER_LOST_EXTENDED') Message: Lost connection to MySQL server at '%s', system error: %d * Error: `2056' (`CR_STMT_CLOSED') Message: Statement closed indirectly because of a preceeding %s() call * Error: `2057' (`CR_NEW_STMT_METADATA') Message: The number of columns in the result set differs from the number of bound buffers. You must reset the statement, rebind the result set columns, and execute the statement again  File: manual.info, Node: problems, Prev: error-messages-client, Up: error-handling C.5 Problems and Common Errors ============================== * Menu: * what-is-crashing:: How to Determine What Is Causing a Problem * common-errors:: Common Errors When Using MySQL Programs * installation-issues:: Installation-Related Issues * administration-issues:: Administration-Related Issues * query-issues:: Query-Related Issues * optimizer-issues:: Optimizer-Related Issues * table-definition-issues:: Table Definition-Related Issues * bugs:: Known Issues in MySQL This section lists some common problems and error messages that you may encounter. It describes how to determine the causes of the problems and what to do to solve them.  File: manual.info, Node: what-is-crashing, Next: common-errors, Prev: problems, Up: problems C.5.1 How to Determine What Is Causing a Problem ------------------------------------------------ When you run into a problem, the first thing you should do is to find out which program or piece of equipment is causing it: * If you have one of the following symptoms, then it is probably a hardware problems (such as memory, motherboard, CPU, or hard disk) or kernel problem: * The keyboard doesn't work. This can normally be checked by pressing the Caps Lock key. If the Caps Lock light doesn't change, you have to replace your keyboard. (Before doing this, you should try to restart your computer and check all cables to the keyboard.) * The mouse pointer doesn't move. * The machine doesn't answer to a remote machine's pings. * Other programs that are not related to MySQL don't behave correctly. * Your system restarted unexpectedly. (A faulty user-level program should never be able to take down your system.) In this case, you should start by checking all your cables and run some diagnostic tool to check your hardware! You should also check whether there are any patches, updates, or service packs for your operating system that could likely solve your problem. Check also that all your libraries (such as `glibc') are up to date. It is always good to use a machine with ECC memory to discover memory problems early. * If your keyboard is locked up, you may be able to recover by logging in to your machine from another machine and executing `kbd_mode -a'. * Please examine your system log file (`/var/log/messages' or similar) for reasons for your problem. If you think the problem is in MySQL, you should also examine MySQL's log files. See *Note server-logs::. * If you don't think you have hardware problems, you should try to find out which program is causing problems. Try using `top', `ps', Task Manager, or some similar program, to check which program is taking all CPU or is locking the machine. * Use `top', `df', or a similar program to check whether you are out of memory, disk space, file descriptors, or some other critical resource. * If the problem is some runaway process, you can always try to kill it. If it doesn't want to die, there is probably a bug in the operating system. If after you have examined all other possibilities and you have concluded that the MySQL server or a MySQL client is causing the problem, it is time to create a bug report for our mailing list or our support team. In the bug report, try to give a very detailed description of how the system is behaving and what you think is happening. You should also state why you think that MySQL is causing the problem. Take into consideration all the situations in this chapter. State any problems exactly how they appear when you examine your system. Use the `copy and paste' method for any output and error messages from programs and log files. Try to describe in detail which program is not working and all symptoms you see. We have in the past received many bug reports that state only `the system doesn't work.' This doesn't provide us with any information about what could be the problem. If a program fails, it is always useful to know the following information: * Has the program in question made a segmentation fault (did it dump core)? * Is the program taking up all available CPU time? Check with `top'. Let the program run for a while, it may simply be evaluating something computationally intensive. * If the *Note `mysqld': mysqld. server is causing problems, can you get any response from it with *Note `mysqladmin -u root ping': mysqladmin. or *Note `mysqladmin -u root processlist': mysqladmin.? * What does a client program say when you try to connect to the MySQL server? (Try with *Note `mysql': mysql, for example.) Does the client jam? Do you get any output from the program? When sending a bug report, you should follow the outline described in *Note bug-reports::.  File: manual.info, Node: common-errors, Next: installation-issues, Prev: what-is-crashing, Up: problems C.5.2 Common Errors When Using MySQL Programs --------------------------------------------- * Menu: * error-access-denied:: `Access denied' * can-not-connect-to-server:: `Can't connect to [local] MySQL server' * error-lost-connection:: `Lost connection to MySQL server' * old-client:: `Client does not support authentication protocol' * password-too-long:: Password Fails When Entered Interactively * blocked-host:: `Host 'HOST_NAME' is blocked' * too-many-connections:: `Too many connections' * out-of-memory:: `Out of memory' * gone-away:: `MySQL server has gone away' * packet-too-large:: `Packet too large' * communication-errors:: Communication Errors and Aborted Connections * full-table:: `The table is full' * cannot-create:: `Can't create/write to file' * commands-out-of-sync:: `Commands out of sync' * ignoring-user:: `Ignoring user' * cannot-find-table:: `Table 'TBL_NAME' doesn't exist' * cannot-initialize-character-set:: `Can't initialize character set' * not-enough-file-handles:: `'FILE' Not Found' and Similar Errors * table-corruption:: Table-Corruption Issues This section lists some errors that users frequently encounter when running MySQL programs. Although the problems show up when you try to run client programs, the solutions to many of the problems involves changing the configuration of the MySQL server.  File: manual.info, Node: error-access-denied, Next: can-not-connect-to-server, Prev: common-errors, Up: common-errors C.5.2.1 `Access denied' ....................... An `Access denied' error can have many causes. Often the problem is related to the MySQL accounts that the server permits client programs to use when connecting. See *Note privilege-system::, and *Note access-denied::.  File: manual.info, Node: can-not-connect-to-server, Next: error-lost-connection, Prev: error-access-denied, Up: common-errors C.5.2.2 `Can't connect to [local] MySQL server' ............................................... * Menu: * can-not-connect-to-server-on-windows:: `Connection to MySQL Server Failing on Windows' A MySQL client on Unix can connect to the *Note `mysqld': mysqld. server in two different ways: By using a Unix socket file to connect through a file in the file system (default `/tmp/mysql.sock'), or by using TCP/IP, which connects through a port number. A Unix socket file connection is faster than TCP/IP, but can be used only when connecting to a server on the same computer. A Unix socket file is used if you don't specify a host name or if you specify the special host name `localhost'. If the MySQL server is running on Windows, you can connect using TCP/IP. If the server is started with the `--enable-named-pipe' option, you can also connect with named pipes if you run the client on the host where the server is running. The name of the named pipe is `MySQL' by default. If you don't give a host name when connecting to *Note `mysqld': mysqld, a MySQL client first tries to connect to the named pipe. If that doesn't work, it connects to the TCP/IP port. You can force the use of named pipes on Windows by using `.' as the host name. The error (2002) `Can't connect to ...' normally means that there is no MySQL server running on the system or that you are using an incorrect Unix socket file name or TCP/IP port number when trying to connect to the server. You should also check that the TCP/IP port you are using has not been blocked by a firewall or port blocking service. The error (2003) `Can't connect to MySQL server on 'SERVER' (10061)' indicates that the network connection has been refused. You should check that there is a MySQL server running, that it has network connections enabled, and that the network port you specified is the one configured on the server. Start by checking whether there is a process named *Note `mysqld': mysqld. running on your server host. (Use `ps xa | grep mysqld' on Unix or the Task Manager on Windows.) If there is no such process, you should start the server. See *Note starting-server::. If a *Note `mysqld': mysqld. process is running, you can check it by trying the following commands. The port number or Unix socket file name might be different in your setup. `host_ip' represents the IP address of the machine where the server is running. shell> mysqladmin version shell> mysqladmin variables shell> mysqladmin -h `hostname` version variables shell> mysqladmin -h `hostname` --port=3306 version shell> mysqladmin -h host_ip version shell> mysqladmin --protocol=SOCKET --socket=/tmp/mysql.sock version Note the use of backticks rather than forward quotation marks with the `hostname' command; these cause the output of `hostname' (that is, the current host name) to be substituted into the *Note `mysqladmin': mysqladmin. command. If you have no `hostname' command or are running on Windows, you can manually type the host name of your machine (without backticks) following the `-h' option. You can also try `-h 127.0.0.1' to connect with TCP/IP to the local host. Make sure that the server has not been configured to ignore network connections or (if you are attempting to connect remotely) that it has not been configured to listen only locally on its network interfaces. If the server was started with `--skip-networking', it will not accept TCP/IP connections at all. If the server was started with `--bind-address=127.0.0.1', it will listen for TCP/IP connections only locally on the loopback interface and will not accept remote connections. Check to make sure that there is no firewall blocking access to MySQL. Your firewall may be configured on the basis of the application being executed, or the port number used by MySQL for communication (3306 by default). Under Linux or Unix, check your IP tables (or similar) configuration to ensure that the port has not been blocked. Under Windows, applications such as ZoneAlarm or the Windows XP personal firewall may need to be configured not to block the MySQL port. Here are some reasons the `Can't connect to local MySQL server' error might occur: * *Note `mysqld': mysqld. is not running on the local host. Check your operating system's process list to ensure the *Note `mysqld': mysqld. process is present. * You're running a MySQL server on Windows with many TCP/IP connections to it. If you're experiencing that quite often your clients get that error, you can find a workaround here: *Note can-not-connect-to-server-on-windows::. * Someone has removed the Unix socket file that *Note `mysqld': mysqld. uses (`/tmp/mysql.sock' by default). For example, you might have a `cron' job that removes old files from the `/tmp' directory. You can always run *Note `mysqladmin version': mysqladmin. to check whether the Unix socket file that *Note `mysqladmin': mysqladmin. is trying to use really exists. The fix in this case is to change the `cron' job to not remove `mysql.sock' or to place the socket file somewhere else. See *Note problems-with-mysql-sock::. * You have started the *Note `mysqld': mysqld. server with the `--socket=/path/to/socket' option, but forgotten to tell client programs the new name of the socket file. If you change the socket path name for the server, you must also notify the MySQL clients. You can do this by providing the same `--socket' option when you run client programs. You also need to ensure that clients have permission to access the `mysql.sock' file. To find out where the socket file is, you can do: shell> netstat -ln | grep mysql See *Note problems-with-mysql-sock::. * You are using Linux and one server thread has died (dumped core). In this case, you must kill the other *Note `mysqld': mysqld. threads (for example, with *Note `kill': kill. or with the *Note `mysql_zap': mysql-zap. script) before you can restart the MySQL server. See *Note crashing::. * The server or client program might not have the proper access privileges for the directory that holds the Unix socket file or the socket file itself. In this case, you must either change the access privileges for the directory or socket file so that the server and clients can access them, or restart *Note `mysqld': mysqld. with a `--socket' option that specifies a socket file name in a directory where the server can create it and where client programs can access it. If you get the error message `Can't connect to MySQL server on some_host', you can try the following things to find out what the problem is: * Check whether the server is running on that host by executing `telnet some_host 3306' and pressing the Enter key a couple of times. (3306 is the default MySQL port number. Change the value if your server is listening to a different port.) If there is a MySQL server running and listening to the port, you should get a response that includes the server's version number. If you get an error such as `telnet: Unable to connect to remote host: Connection refused', then there is no server running on the given port. * If the server is running on the local host, try using *Note `mysqladmin -h localhost variables': mysqladmin. to connect using the Unix socket file. Verify the TCP/IP port number that the server is configured to listen to (it is the value of the `port' variable.) * If you are running under Linux and Security-Enhanced Linux (SELinux) is enabled, make sure you have disabled SELinux protection for the `mysqld' process.  File: manual.info, Node: can-not-connect-to-server-on-windows, Prev: can-not-connect-to-server, Up: can-not-connect-to-server C.5.2.3 `Connection to MySQL Server Failing on Windows' ....................................................... When you're running a MySQL server on Windows with many TCP/IP connections to it, and you're experiencing that quite often your clients get a `Can't connect to MySQL server' error, the reason might be that Windows does not allow for enough ephemeral (short-lived) ports to serve those connections. The purpose of `TIME_WAIT' is to keep a connection accepting packets even after the connection has been closed. This is because Internet routing can cause a packet to take a slow route to its destination and it may arrive after both sides have agreed to close. If the port is in use for a new connection, that packet from the old connection could break the protocol or compromise personal information from the original connection. The `TIME_WAIT' delay prevents this by ensuring that the port cannot be reused until after some time has been permitted for those delayed packets to arrive. It is safe to reduce `TIME_WAIT' greatly on LAN connections because there is little chance of packets arriving at very long delays, as they could through the Internet with its comparatively large distances and latencies. Windows permits ephemeral (short-lived) TCP ports to the user. After any port is closed it will remain in a `TIME_WAIT' status for 120 seconds. The port will not be available again until this time expires. The default range of port numbers depends on the version of Windows, with a more limited number of ports in older versions: * Windows through Server 2003: Ports in range 1025-5000 * Windows Vista, Server 2008, and newer: Ports in range 49152-65535 With a small stack of available TCP ports (5000) and a high number of TCP ports being open and closed over a short period of time along with the `TIME_WAIT' status you have a good chance for running out of ports. There are two ways to address this problem: * Reduce the number of TCP ports consumed quickly by investigating connection pooling or persistent connections where possible * Tune some settings in the Windows registry (see below) * IMPORTANT: The following procedure involves modifying the Windows registry. Before you modify the registry, make sure to back it up and make sure that you understand how to restore the registry if a problem occurs. For information about how to back up, restore, and edit the registry, view the following article in the Microsoft Knowledge Base: `http://support.microsoft.com/kb/256986/EN-US/'. * 1. Start Registry Editor (`Regedt32.exe'). 2. Locate the following key in the registry: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters 3. On the `Edit' menu, click `Add Value', and then add the following registry value: Value Name: MaxUserPort Data Type: REG_DWORD Value: 65534 This sets the number of ephemeral ports available to any user. The valid range is between 5000 and 65534 (decimal). The default value is 0x1388 (5000 decimal). 4. On the `Edit' menu, click `Add Value', and then add the following registry value: Value Name: TcpTimedWaitDelay Data Type: REG_DWORD Value: 30 This sets the number of seconds to hold a TCP port connection in `TIME_WAIT' state before closing. The valid range is between 0 (zero) and 300 (decimal). The default value is 0x78 (120 decimal). 5. Quit Registry Editor. 6. Reboot the machine. Note: Undoing the above should be as simple as deleting the registry entries you've created.  File: manual.info, Node: error-lost-connection, Next: old-client, Prev: can-not-connect-to-server, Up: common-errors C.5.2.4 `Lost connection to MySQL server' ......................................... There are three likely causes for this error message. Usually it indicates network connectivity trouble and you should check the condition of your network if this error occurs frequently. If the error message includes `during query,' this is probably the case you are experiencing. Sometimes the `during query' form happens when millions of rows are being sent as part of one or more queries. If you know that this is happening, you should try increasing `net_read_timeout' from its default of 30 seconds to 60 seconds or longer, sufficient for the data transfer to complete. More rarely, it can happen when the client is attempting the initial connection to the server. In this case, if your `connect_timeout' value is set to only a few seconds, you may be able to resolve the problem by increasing it to ten seconds, perhaps more if you have a very long distance or slow connection. You can determine whether you are experiencing this more uncommon cause by using `SHOW GLOBAL STATUS LIKE 'Aborted_connects''. It will increase by one for each initial connection attempt that the server aborts. You may see `reading authorization packet' as part of the error message; if so, that also suggests that this is the solution that you need. If the cause is none of those just described, you may be experiencing a problem with *Note `BLOB': blob. values that are larger than `max_allowed_packet', which can cause this error with some clients. Sometime you may see `packet too large' as part of the error message, and that confirms that you need to increase `max_allowed_packet'.  File: manual.info, Node: old-client, Next: password-too-long, Prev: error-lost-connection, Up: common-errors C.5.2.5 `Client does not support authentication protocol' ......................................................... MySQL 5.1 uses an authentication protocol based on a password hashing algorithm that is incompatible with that used by older (pre-4.1) clients. If you upgrade the server from 4.0, attempts to connect to it with an older client may fail with the following message: shell> mysql Client does not support authentication protocol requested by server; consider upgrading MySQL client To solve this problem, you should use one of the following approaches: * Upgrade all client programs to use a 4.1.1 or newer client library. * When connecting to the server with a pre-4.1 client program, use an account that still has a pre-4.1-style password. * Reset the password to pre-4.1 style for each user that needs to use a pre-4.1 client program. This can be done using the *Note `SET PASSWORD': set-password. statement and the `OLD_PASSWORD()' function: mysql> SET PASSWORD FOR -> 'SOME_USER'@'SOME_HOST' = OLD_PASSWORD('NEWPWD'); Alternatively, use *Note `UPDATE': update. and *Note `FLUSH PRIVILEGES': flush.: mysql> UPDATE mysql.user SET Password = OLD_PASSWORD('NEWPWD') -> WHERE Host = 'SOME_HOST' AND User = 'SOME_USER'; mysql> FLUSH PRIVILEGES; Substitute the password you want to use for `NEWPWD' in the preceding examples. MySQL cannot tell you what the original password was, so you'll need to pick a new one. * Tell the server to use the older password hashing algorithm: 1. Start *Note `mysqld': mysqld. with the `--old-passwords' option. 2. Assign an old-format password to each account that has had its password updated to the longer 4.1 format. You can identify these accounts with the following query: mysql> SELECT Host, User, Password FROM mysql.user -> WHERE LENGTH(Password) > 16; For each account record displayed by the query, use the `Host' and `User' values and assign a password using the `OLD_PASSWORD()' function and either *Note `SET PASSWORD': set-password. or *Note `UPDATE': update, as described earlier. *Note*: In older versions of PHP, the `mysql' extension does not support the authentication protocol in MySQL 4.1.1 and higher. This is true regardless of the PHP version being used. If you wish to use the `mysql' extension with MySQL 4.1 or newer, you may need to follow one of the options discussed above for configuring MySQL to work with old clients. The `mysqli' extension (stands for "MySQL, Improved"; added in PHP 5) is compatible with the improved password hashing employed in MySQL 4.1 and higher, and no special configuration of MySQL need be done to use this MySQL client library. For more information about the `mysqli' extension, see `http://php.net/mysqli'. It may also be possible to compile the older `mysql' extension against the new MySQL client library. This is beyond the scope of this Manual; consult the PHP documentation for more information. You also be able to obtain assistance with these issues in our MySQL with PHP forum (http://forums.mysql.com/list.php?52). For additional background on password hashing and authentication, see *Note password-hashing::.  File: manual.info, Node: password-too-long, Next: blocked-host, Prev: old-client, Up: common-errors C.5.2.6 Password Fails When Entered Interactively ................................................. MySQL client programs prompt for a password when invoked with a `--password' or `-p' option that has no following password value: shell> mysql -u USER_NAME -p Enter password: On some systems, you may find that your password works when specified in an option file or on the command line, but not when you enter it interactively at the `Enter password:' prompt. This occurs when the library provided by the system to read passwords limits password values to a small number of characters (typically eight). That is a problem with the system library, not with MySQL. To work around it, change your MySQL password to a value that is eight or fewer characters long, or put your password in an option file.  File: manual.info, Node: blocked-host, Next: too-many-connections, Prev: password-too-long, Up: common-errors C.5.2.7 `Host 'HOST_NAME' is blocked' ..................................... If you get the following error, it means that *Note `mysqld': mysqld. has received many connect requests from the host `'HOST_NAME'' that have been interrupted in the middle: Host 'HOST_NAME' is blocked because of many connection errors. Unblock with 'mysqladmin flush-hosts' The number of interrupted connect requests permitted is determined by the value of the `max_connect_errors' system variable. After `max_connect_errors' failed requests, *Note `mysqld': mysqld. assumes that something is wrong (for example, that someone is trying to break in), and blocks the host from further connections until you execute a *Note `mysqladmin flush-hosts': mysqladmin. command or issue a *Note `FLUSH HOSTS': flush. statement. See *Note server-system-variables::. By default, *Note `mysqld': mysqld. blocks a host after 10 connection errors. You can adjust the value by starting the server like this: shell> mysqld_safe --max_connect_errors=10000 & If you get this error message for a given host, you should first verify that there isn't anything wrong with TCP/IP connections from that host. If you are having network problems, it does you no good to increase the value of the `max_connect_errors' variable.  File: manual.info, Node: too-many-connections, Next: out-of-memory, Prev: blocked-host, Up: common-errors C.5.2.8 `Too many connections' .............................. If you get a `Too many connections' error when you try to connect to the *Note `mysqld': mysqld. server, this means that all available connections are in use by other clients. The number of connections permitted is controlled by the `max_connections' system variable. Beginning with MySQL 5.1.15, its default value is 151 to improve performance when MySQL is used with the Apache Web server. (Previously, the default was 100.) If you need to support more connections, you should set a larger value for this variable. *Note `mysqld': mysqld. actually permits `max_connections+1' clients to connect. The extra connection is reserved for use by accounts that have the `SUPER' privilege. By granting the `SUPER' privilege to administrators and not to normal users (who should not need it), an administrator can connect to the server and use *Note `SHOW PROCESSLIST': show-processlist. to diagnose problems even if the maximum number of unprivileged clients are connected. See *Note show-processlist::. The maximum number of connections MySQL can support depends on the quality of the thread library on a given platform, the amount of RAM available, how much RAM is used for each connection, the workload from each connection, and the desired response time. Linux or Solaris should be able to support at 500 to 1000 simultaneous connections routinely and as many as 10,000 connections if you have many gigabytes of RAM available and the workload from each is low or the response time target undemanding. Windows is limited to (open tables x 2 + open connections) < 2048 due to the Posix compatibility layer used on that platform. Increasing `open-files-limit' may be necessary. Also see *Note linux-installation::, for how to raise the operating system limit on how many handles can be used by MySQL.  File: manual.info, Node: out-of-memory, Next: gone-away, Prev: too-many-connections, Up: common-errors C.5.2.9 `Out of memory' ....................... If you issue a query using the *Note `mysql': mysql. client program and receive an error like the following one, it means that *Note `mysql': mysql. does not have enough memory to store the entire query result: mysql: Out of memory at line 42, 'malloc.c' mysql: needed 8136 byte (8k), memory in use: 12481367 bytes (12189k) ERROR 2008: MySQL client ran out of memory To remedy the problem, first check whether your query is correct. Is it reasonable that it should return so many rows? If not, correct the query and try again. Otherwise, you can invoke *Note `mysql': mysql. with the `--quick' option. This causes it to use the *Note `mysql_use_result()': mysql-use-result. C API function to retrieve the result set, which places less of a load on the client (but more on the server).  File: manual.info, Node: gone-away, Next: packet-too-large, Prev: out-of-memory, Up: common-errors C.5.2.10 `MySQL server has gone away' ..................................... This section also covers the related `Lost connection to server during query' error. The most common reason for the `MySQL server has gone away' error is that the server timed out and closed the connection. In this case, you normally get one of the following error codes (which one you get is operating system-dependent). Error Code Description `CR_SERVER_GONE_ERROR' The client couldn't send a question to the server. `CR_SERVER_LOST' The client didn't get an error when writing to the server, but it didn't get a full answer (or any answer) to the question. By default, the server closes the connection after eight hours if nothing has happened. You can change the time limit by setting the `wait_timeout' variable when you start *Note `mysqld': mysqld. See *Note server-system-variables::. If you have a script, you just have to issue the query again for the client to do an automatic reconnection. This assumes that you have automatic reconnection in the client enabled (which is the default for the `mysql' command-line client). Some other common reasons for the `MySQL server has gone away' error are: * You (or the db administrator) has killed the running thread with a *Note `KILL': kill. statement or a *Note `mysqladmin kill': mysqladmin. command. * You tried to run a query after closing the connection to the server. This indicates a logic error in the application that should be corrected. * A client application running on a different host does not have the necessary privileges to connect to the MySQL server from that host. * You got a timeout from the TCP/IP connection on the client side. This may happen if you have been using the commands: *Note `mysql_options(..., MYSQL_OPT_READ_TIMEOUT,...)': mysql-options. or *Note `mysql_options(..., MYSQL_OPT_WRITE_TIMEOUT,...)': mysql-options. In this case increasing the timeout may help solve the problem. * You have encountered a timeout on the server side and the automatic reconnection in the client is disabled (the `reconnect' flag in the `MYSQL' structure is equal to 0). * You are using a Windows client and the server had dropped the connection (probably because `wait_timeout' expired) before the command was issued. The problem on Windows is that in some cases MySQL doesn't get an error from the OS when writing to the TCP/IP connection to the server, but instead gets the error when trying to read the answer from the connection. Prior to MySQL 5.1.8, even if the `reconnect' flag in the `MYSQL' structure is equal to 1, MySQL does not automatically reconnect and re-issue the query as it doesn't know if the server did get the original query or not. The solution to this is to either do a *Note `mysql_ping()': mysql-ping. on the connection if there has been a long time since the last query (this is what `MyODBC' does) or set `wait_timeout' on the *Note `mysqld': mysqld. server so high that it in practice never times out. * You can also get these errors if you send a query to the server that is incorrect or too large. If *Note `mysqld': mysqld. receives a packet that is too large or out of order, it assumes that something has gone wrong with the client and closes the connection. If you need big queries (for example, if you are working with big *Note `BLOB': blob. columns), you can increase the query limit by setting the server's `max_allowed_packet' variable, which has a default value of 1MB. You may also need to increase the maximum packet size on the client end. More information on setting the packet size is given in *Note packet-too-large::. An *Note `INSERT': insert. or *Note `REPLACE': replace. statement that inserts a great many rows can also cause these sorts of errors. Either one of these statements sends a single request to the server irrespective of the number of rows to be inserted; thus, you can often avoid the error by reducing the number of rows sent per *Note `INSERT': insert. or *Note `REPLACE': replace. * You also get a lost connection if you are sending a packet 16MB or larger if your client is older than 4.0.8 and your server is 4.0.8 and above, or the other way around. * It is also possible to see this error if host name lookups fail (for example, if the DNS server on which your server or network relies goes down). This is because MySQL is dependent on the host system for name resolution, but has no way of knowing whether it is working--from MySQL's point of view the problem is indistinguishable from any other network timeout. You may also see the `MySQL server has gone away' error if MySQL is started with the `--skip-networking' option. Another networking issue that can cause this error occurs if the MySQL port (default 3306) is blocked by your firewall, thus preventing any connections at all to the MySQL server. * You can also encounter this error with applications that fork child processes, all of which try to use the same connection to the MySQL server. This can be avoided by using a separate connection for each child process. * You have encountered a bug where the server died while executing the query. You can check whether the MySQL server died and restarted by executing *Note `mysqladmin version': mysqladmin. and examining the server's uptime. If the client connection was broken because *Note `mysqld': mysqld. crashed and restarted, you should concentrate on finding the reason for the crash. Start by checking whether issuing the query again kills the server again. See *Note crashing::. You can get more information about the lost connections by starting *Note `mysqld': mysqld. with the `--log-warnings=2' option. This logs some of the disconnected errors in the `hostname.err' file. See *Note error-log::. If you want to create a bug report regarding this problem, be sure that you include the following information: * Indicate whether the MySQL server died. You can find information about this in the server error log. See *Note crashing::. * If a specific query kills *Note `mysqld': mysqld. and the tables involved were checked with *Note `CHECK TABLE': check-table. before you ran the query, can you provide a reproducible test case? See MySQL Internals: Porting (http://forge.mysql.com/wiki/MySQL_Internals_Porting). * What is the value of the `wait_timeout' system variable in the MySQL server? (*Note `mysqladmin variables': mysqladmin. gives you the value of this variable.) * Have you tried to run *Note `mysqld': mysqld. with the general query log enabled to determine whether the problem query appears in the log? (See *Note query-log::.) See also *Note communication-errors::, and *Note bug-reports::.  File: manual.info, Node: packet-too-large, Next: communication-errors, Prev: gone-away, Up: common-errors C.5.2.11 `Packet too large' ........................... A communication packet is a single SQL statement sent to the MySQL server, a single row that is sent to the client, or a binary log event sent from a master replication server to a slave. The largest possible packet that can be transmitted to or from a MySQL 5.1 server or client is 1GB. When a MySQL client or the *Note `mysqld': mysqld. server receives a packet bigger than `max_allowed_packet' bytes, it issues a `Packet too large' error and closes the connection. With some clients, you may also get a `Lost connection to MySQL server during query' error if the communication packet is too large. Both the client and the server have their own `max_allowed_packet' variable, so if you want to handle big packets, you must increase this variable both in the client and in the server. If you are using the *Note `mysql': mysql. client program, its default `max_allowed_packet' variable is 16MB. To set a larger value, start *Note `mysql': mysql. like this: shell> mysql --max_allowed_packet=32M That sets the packet size to 32MB. The server's default `max_allowed_packet' value is 1MB. You can increase this if the server needs to handle big queries (for example, if you are working with big *Note `BLOB': blob. columns). For example, to set the variable to 16MB, start the server like this: shell> mysqld --max_allowed_packet=16M You can also use an option file to set `max_allowed_packet'. For example, to set the size for the server to 16MB, add the following lines in an option file: [mysqld] max_allowed_packet=16M It is safe to increase the value of this variable because the extra memory is allocated only when needed. For example, *Note `mysqld': mysqld. allocates more memory only when you issue a long query or when *Note `mysqld': mysqld. must return a large result row. The small default value of the variable is a precaution to catch incorrect packets between the client and server and also to ensure that you do not run out of memory by using large packets accidentally. You can also get strange problems with large packets if you are using large *Note `BLOB': blob. values but have not given *Note `mysqld': mysqld. access to enough memory to handle the query. If you suspect this is the case, try adding `ulimit -d 256000' to the beginning of the *Note `mysqld_safe': mysqld-safe. script and restarting *Note `mysqld': mysqld.  File: manual.info, Node: communication-errors, Next: full-table, Prev: packet-too-large, Up: common-errors C.5.2.12 Communication Errors and Aborted Connections ..................................................... The server error log can be a useful source of information about connection problems. See *Note error-log::. If you start the server with the `--log-warnings' option, you might find messages like this in your error log: 010301 14:38:23 Aborted connection 854 to db: 'users' user: 'josh' If a client successfully connects but later disconnects improperly or is terminated, the server increments the `Aborted_clients' status variable, and logs an `Aborted connection' message to the error log. The cause can be any of the following: * The client program did not call *Note `mysql_close()': mysql-close. before exiting. * The client had been sleeping more than `wait_timeout' or `interactive_timeout' seconds without issuing any requests to the server. See *Note server-system-variables::. * The client program ended abruptly in the middle of a data transfer. If a client is unable even to connect, the server increments the `Aborted_connects' status variable. Unsuccessful connect attempts can occur for the following reasons: * A client doesn't have privileges to connect to a database. * A client uses an incorrect password. * A connection packet doesn't contain the right information. * It takes more than `connect_timeout' seconds to get a connect packet. See *Note server-system-variables::. If these kinds of things happen, it might indicate that someone is trying to break into your server! Messages for these types of problems are logged to the general query log if it is enabled. Other reasons for problems with aborted clients or aborted connections: * Use of Ethernet protocol with Linux, both half and full duplex. Many Linux Ethernet drivers have this bug. You should test for this bug by transferring a huge file using FTP between the client and server machines. If a transfer goes in burst-pause-burst-pause mode, you are experiencing a Linux duplex syndrome. The only solution is switching the duplex mode for both your network card and hub/switch to either full duplex or to half duplex and testing the results to determine the best setting. * Some problem with the thread library that causes interrupts on reads. * Badly configured TCP/IP. * Faulty Ethernets, hubs, switches, cables, and so forth. This can be diagnosed properly only by replacing hardware. * The `max_allowed_packet' variable value is too small or queries require more memory than you have allocated for *Note `mysqld': mysqld. See *Note packet-too-large::. See also *Note gone-away::.  File: manual.info, Node: full-table, Next: cannot-create, Prev: communication-errors, Up: common-errors C.5.2.13 `The table is full' ............................ If a table-full error occurs, it may be that the disk is full or that the table has reached its maximum size. The effective maximum table size for MySQL databases is usually determined by operating system constraints on file sizes, not by MySQL internal limits. See *Note table-size-limit::.  File: manual.info, Node: cannot-create, Next: commands-out-of-sync, Prev: full-table, Up: common-errors C.5.2.14 `Can't create/write to file' ..................................... If you get an error of the following type for some queries, it means that MySQL cannot create a temporary file for the result set in the temporary directory: Can't create/write to file '\\sqla3fe_0.ism'. The preceding error is a typical message for Windows; the Unix message is similar. One fix is to start *Note `mysqld': mysqld. with the `--tmpdir' option or to add the option to the `[mysqld]' section of your option file. For example, to specify a directory of `C:\temp', use these lines: [mysqld] tmpdir=C:/temp The `C:\temp' directory must exist and have sufficient space for the MySQL server to write to. See *Note option-files::. Another cause of this error can be permissions issues. Make sure that the MySQL server can write to the `tmpdir' directory. Check also the error code that you get with *Note `perror': perror. One reason the server cannot write to a table is that the file system is full: shell> perror 28 OS error code 28: No space left on device If you get an error of the following type during startup, it indicates that the file system or directory used for storing data files is write protected. Providing the write error is to a test file, This error is not serious and can be safely ignored. Can't create test file /usr/local/mysql/data/master.lower-test  File: manual.info, Node: commands-out-of-sync, Next: ignoring-user, Prev: cannot-create, Up: common-errors C.5.2.15 `Commands out of sync' ............................... If you get `Commands out of sync; you can't run this command now' in your client code, you are calling client functions in the wrong order. This can happen, for example, if you are using *Note `mysql_use_result()': mysql-use-result. and try to execute a new query before you have called *Note `mysql_free_result()': mysql-free-result. It can also happen if you try to execute two queries that return data without calling *Note `mysql_use_result()': mysql-use-result. or *Note `mysql_store_result()': mysql-store-result. in between.  File: manual.info, Node: ignoring-user, Next: cannot-find-table, Prev: commands-out-of-sync, Up: common-errors C.5.2.16 `Ignoring user' ........................ If you get the following error, it means that when *Note `mysqld': mysqld. was started or when it reloaded the grant tables, it found an account in the `user' table that had an invalid password. `Found wrong password for user 'SOME_USER'@'SOME_HOST'; ignoring user' As a result, the account is simply ignored by the permission system. The following list indicates possible causes of and fixes for this problem: * You may be running a new version of *Note `mysqld': mysqld. with an old `user' table. You can check this by executing *Note `mysqlshow mysql user': mysqlshow. to see whether the `Password' column is shorter than 16 characters. If so, you can correct this condition by running the `scripts/add_long_password' script. * The account has an old password (eight characters long). Update the account in the `user' table to have a new password. * You have specified a password in the `user' table without using the `PASSWORD()' function. Use *Note `mysql': mysql. to update the account in the `user' table with a new password, making sure to use the `PASSWORD()' function: mysql> UPDATE user SET Password=PASSWORD('NEWPWD') -> WHERE User='SOME_USER' AND Host='SOME_HOST';  File: manual.info, Node: cannot-find-table, Next: cannot-initialize-character-set, Prev: ignoring-user, Up: common-errors C.5.2.17 `Table 'TBL_NAME' doesn't exist' ......................................... If you get either of the following errors, it usually means that no table exists in the default database with the given name: Table 'TBL_NAME' doesn't exist Can't find file: 'TBL_NAME' (errno: 2) In some cases, it may be that the table does exist but that you are referring to it incorrectly: * Because MySQL uses directories and files to store databases and tables, database and table names are case sensitive if they are located on a file system that has case-sensitive file names. * Even for file systems that are not case sensitive, such as on Windows, all references to a given table within a query must use the same lettercase. You can check which tables are in the default database with *Note `SHOW TABLES': show-tables. See *Note show::.  File: manual.info, Node: cannot-initialize-character-set, Next: not-enough-file-handles, Prev: cannot-find-table, Up: common-errors C.5.2.18 `Can't initialize character set' ......................................... You might see an error like this if you have character set problems: MySQL Connection Failed: Can't initialize character set CHARSET_NAME This error can have any of the following causes: * The character set is a multi-byte character set and you have no support for the character set in the client. In this case, you need to recompile the client by running `configure' with the `--with-charset=CHARSET_NAME' or `--with-extra-charsets=CHARSET_NAME' option. See *Note source-configuration-options::. All standard MySQL binaries are compiled with `--with-extra-charsets=complex' or (for Windows) `--with-extra-charsets=complex', which enables support for all multi-byte character sets. See *Note source-configuration-options::. * The character set is a simple character set that is not compiled into *Note `mysqld': mysqld, and the character set definition files are not in the place where the client expects to find them. In this case, you need to use one of the following methods to solve the problem: * Recompile the client with support for the character set. See *Note source-configuration-options::. * Specify to the client the directory where the character set definition files are located. For many clients, you can do this with the `--character-sets-dir' option. * Copy the character definition files to the path where the client expects them to be.  File: manual.info, Node: not-enough-file-handles, Next: table-corruption, Prev: cannot-initialize-character-set, Up: common-errors C.5.2.19 `'FILE' Not Found' and Similar Errors .............................................. If you get `ERROR '...' not found (errno: 23)', `Can't open file: ... (errno: 24)', or any other error with `errno 23' or `errno 24' from MySQL, it means that you haven't allocated enough file descriptors for the MySQL server. You can use the *Note `perror': perror. utility to get a description of what the error number means: shell> perror 23 OS error code 23: File table overflow shell> perror 24 OS error code 24: Too many open files shell> perror 11 OS error code 11: Resource temporarily unavailable The problem here is that *Note `mysqld': mysqld. is trying to keep open too many files simultaneously. You can either tell *Note `mysqld': mysqld. not to open so many files at once or increase the number of file descriptors available to *Note `mysqld': mysqld. To tell *Note `mysqld': mysqld. to keep open fewer files at a time, you can make the table cache smaller by reducing the value of the `table_open_cache' system variable (the default value is 64). This may not entirely prevent running out of file descriptors because in some circumstances the server may attempt to extend the cache size temporarily, as described in *Note table-cache::. Reducing the value of `max_connections' also reduces the number of open files (the default value is 100). To change the number of file descriptors available to *Note `mysqld': mysqld, you can use the `--open-files-limit' option to *Note `mysqld_safe': mysqld-safe. or set the `open_files_limit' system variable. See *Note server-system-variables::. The easiest way to set these values is to add an option to your option file. See *Note option-files::. If you have an old version of *Note `mysqld': mysqld. that doesn't support setting the open files limit, you can edit the *Note `mysqld_safe': mysqld-safe. script. There is a commented-out line `ulimit -n 256' in the script. You can remove the ``#'' character to uncomment this line, and change the number `256' to set the number of file descriptors to be made available to *Note `mysqld': mysqld. `--open-files-limit' and `ulimit' can increase the number of file descriptors, but only up to the limit imposed by the operating system. There is also a `hard' limit that can be overridden only if you start *Note `mysqld_safe': mysqld-safe. or *Note `mysqld': mysqld. as `root' (just remember that you also need to start the server with the `--user' option in this case so that it does not continue to run as `root' after it starts up). If you need to increase the operating system limit on the number of file descriptors available to each process, consult the documentation for your system. *Note*: If you run the `tcsh' shell, `ulimit' does not work! `tcsh' also reports incorrect values when you ask for the current limits. In this case, you should start *Note `mysqld_safe': mysqld-safe. using `sh'.  File: manual.info, Node: table-corruption, Prev: not-enough-file-handles, Up: common-errors C.5.2.20 Table-Corruption Issues ................................ If you have started *Note `mysqld': mysqld. with `--myisam-recover', MySQL automatically checks and tries to repair `MyISAM' tables if they are marked as 'not closed properly' or 'crashed'. If this happens, MySQL writes an entry in the `hostname.err' file `'Warning: Checking table ...'' which is followed by `Warning: Repairing table' if the table needs to be repaired. If you get a lot of these errors, without *Note `mysqld': mysqld. having died unexpectedly just before, then something is wrong and needs to be investigated further. See also *Note server-options::, and *Note reproducible-test-case::.  File: manual.info, Node: installation-issues, Next: administration-issues, Prev: common-errors, Up: problems C.5.3 Installation-Related Issues --------------------------------- * Menu: * file-permissions:: Problems with File Permissions  File: manual.info, Node: file-permissions, Prev: installation-issues, Up: installation-issues C.5.3.1 Problems with File Permissions ...................................... If you have problems with file permissions, the `UMASK' environment variable might be set incorrectly when *Note `mysqld': mysqld. starts. For example, MySQL might issue the following error message when you create a table: ERROR: Can't find file: 'path/with/filename.frm' (Errcode: 13) The default `UMASK' value is `0660'. You can change this behavior by starting *Note `mysqld_safe': mysqld-safe. as follows: shell> UMASK=384 # = 600 in octal shell> export UMASK shell> mysqld_safe & By default, MySQL creates database directories with an access permission value of `0700'. You can modify this behavior by setting the `UMASK_DIR' variable. If you set its value, new directories are created with the combined `UMASK' and `UMASK_DIR' values. For example, if you want to give group access to all new directories, you can do this: shell> UMASK_DIR=504 # = 770 in octal shell> export UMASK_DIR shell> mysqld_safe & MySQL assumes that the value for `UMASK' or `UMASK_DIR' is in octal if it starts with a zero. See *Note environment-variables::.  File: manual.info, Node: administration-issues, Next: query-issues, Prev: installation-issues, Up: problems C.5.4 Administration-Related Issues ----------------------------------- * Menu: * resetting-permissions:: How to Reset the Root Password * crashing:: What to Do If MySQL Keeps Crashing * full-disk:: How MySQL Handles a Full Disk * temporary-files:: Where MySQL Stores Temporary Files * problems-with-mysql-sock:: How to Protect or Change the MySQL Unix Socket File * timezone-problems:: Time Zone Problems  File: manual.info, Node: resetting-permissions, Next: crashing, Prev: administration-issues, Up: administration-issues C.5.4.1 How to Reset the Root Password ...................................... * Menu: * resetting-permissions-windows:: Resetting the Root Password: Windows Systems * resetting-permissions-unix:: Resetting the Root Password: Unix Systems * resetting-permissions-generic:: Resetting the Root Password: Generic Instructions If you have never set a `root' password for MySQL, the server does not require a password at all for connecting as `root'. However, this is insecure. For instructions on assigning passwords, see *Note default-privileges::. If you know the `root' password, but want to change it, see *Note set-password::. If you set a `root' password previously, but have forgotten it, you can set a new password. The following sections provide instructions for Windows and Unix systems, as well as generic instructions that apply to any system.  File: manual.info, Node: resetting-permissions-windows, Next: resetting-permissions-unix, Prev: resetting-permissions, Up: resetting-permissions C.5.4.2 Resetting the Root Password: Windows Systems .................................................... On Windows, use the following procedure to reset the password for all MySQL `root' accounts: 1. Log on to your system as Administrator. 2. Stop the MySQL server if it is running. For a server that is running as a Windows service, go to the Services manager: From the `Start' menu, select `Control Panel', then `Administrative Tools', then `Services'. Find the MySQL service in the list and stop it. If your server is not running as a service, you may need to use the Task Manager to force it to stop. 3. Create a text file containing the following statements. Replace the password with the password that you want to use. UPDATE mysql.user SET Password=PASSWORD('MyNewPass') WHERE User='root'; FLUSH PRIVILEGES; Write the *Note `UPDATE': update. and *Note `FLUSH': flush. statements each on a single line. The *Note `UPDATE': update. statement resets the password for all `root' accounts, and the *Note `FLUSH': flush. statement tells the server to reload the grant tables into memory so that it notices the password change. 4. Save the file. For this example, the file will be named `C:\mysql-init.txt'. 5. Open a console window to get to the command prompt: From the `Start' menu, select `Run', then enter `cmd' as the command to be run. 6. Start the MySQL server with the special `--init-file' option (notice that the backslash in the option value is doubled): C:\> C:\mysql\bin\mysqld --init-file=C:\\mysql-init.txt If you installed MySQL to a location other than `C:\mysql', adjust the command accordingly. The server executes the contents of the file named by the `--init-file' option at startup, changing each `root' account password. You can also add the `--console' option to the command if you want server output to appear in the console window rather than in a log file. If you installed MySQL using the MySQL Installation Wizard, you may need to specify a `--defaults-file' option: C:\> "C:\Program Files\MySQL\MySQL Server 5.1\bin\mysqld.exe" --defaults-file="C:\\Program Files\\MySQL\\MySQL Server 5.1\\my.ini" --init-file=C:\\mysql-init.txt The appropriate `--defaults-file' setting can be found using the Services Manager: From the `Start' menu, select `Control Panel', then `Administrative Tools', then `Services'. Find the MySQL service in the list, right-click it, and choose the `Properties' option. The `Path to executable' field contains the `--defaults-file' setting. 7. After the server has started successfully, delete `C:\mysql-init.txt'. You should now be able to connect to the MySQL server as `root' using the new password. Stop the MySQL server, then restart it in normal mode again. If you run the server as a service, start it from the Windows Services window. If you start the server manually, use whatever command you normally use.  File: manual.info, Node: resetting-permissions-unix, Next: resetting-permissions-generic, Prev: resetting-permissions-windows, Up: resetting-permissions C.5.4.3 Resetting the Root Password: Unix Systems ................................................. On Unix, use the following procedure to reset the password for all MySQL `root' accounts. The instructions assume that you will start the server so that it runs using the Unix login account that you normally use for running the server. For example, if you run the server using the `mysql' login account, you should log in as `mysql' before using the instructions. Alternatively, you can log in as `root', but in this case you _must_ start *Note `mysqld': mysqld. with the `--user=mysql' option. If you start the server as `root' without using `--user=mysql', the server may create `root'-owned files in the data directory, such as log files, and these may cause permission-related problems for future server startups. If that happens, you will need to either change the ownership of the files to `mysql' or remove them. 1. Log on to your system as the Unix user that the *Note `mysqld': mysqld. server runs as (for example, `mysql'). 2. Locate the `.pid' file that contains the server's process ID. The exact location and name of this file depend on your distribution, host name, and configuration. Common locations are `/var/lib/mysql/', `/var/run/mysqld/', and `/usr/local/mysql/data/'. Generally, the file name has an extension of `.pid' and begins with either `mysqld' or your system's host name. You can stop the MySQL server by sending a normal `kill' (not `kill -9') to the *Note `mysqld': mysqld. process, using the path name of the `.pid' file in the following command: shell> kill `cat /mysql-data-directory/host_name.pid` Use backticks (not forward quotation marks) with the `cat' command. These cause the output of `cat' to be substituted into the `kill' command. 3. Create a text file containing the following statements. Replace the password with the password that you want to use. UPDATE mysql.user SET Password=PASSWORD('MyNewPass') WHERE User='root'; FLUSH PRIVILEGES; Write the *Note `UPDATE': update. and *Note `FLUSH': flush. statements each on a single line. The *Note `UPDATE': update. statement resets the password for all `root' accounts, and the *Note `FLUSH': flush. statement tells the server to reload the grant tables into memory so that it notices the password change. 4. Save the file. For this example, the file will be named `/home/me/mysql-init'. The file contains the password, so it should not be saved where it can be read by other users. If you are not logged in as `mysql' (the user the server runs as), make sure that the file has permissions that permit `mysql' to read it. 5. Start the MySQL server with the special `--init-file' option: shell> mysqld_safe --init-file=/home/me/mysql-init & The server executes the contents of the file named by the `--init-file' option at startup, changing each `root' account password. 6. After the server has started successfully, delete `/home/me/mysql-init'. You should now be able to connect to the MySQL server as `root' using the new password. Stop the server and restart it normally.  File: manual.info, Node: resetting-permissions-generic, Prev: resetting-permissions-unix, Up: resetting-permissions C.5.4.4 Resetting the Root Password: Generic Instructions ......................................................... The preceding sections provide password-resetting instructions for Windows and Unix systems. Alternatively, on any platform, you can set the new password using the *Note `mysql': mysql. client (but this approach is less secure): 1. Stop *Note `mysqld': mysqld. and restart it with the `--skip-grant-tables' option. This enables anyone to connect without a password and with all privileges. Because this is insecure, you might want to use `--skip-grant-tables' in conjunction with `--skip-networking' to prevent remote clients from connecting. 2. Connect to the *Note `mysqld': mysqld. server with this command: shell> mysql 3. Issue the following statements in the *Note `mysql': mysql. client. Replace the password with the password that you want to use. mysql> UPDATE mysql.user SET Password=PASSWORD('MyNewPass') -> WHERE User='root'; mysql> FLUSH PRIVILEGES; The *Note `FLUSH': flush. statement tells the server to reload the grant tables into memory so that it notices the password change. You should now be able to connect to the MySQL server as `root' using the new password. Stop the server, then restart it normally (without the `--skip-grant-tables' and `--skip-networking' options).  File: manual.info, Node: crashing, Next: full-disk, Prev: resetting-permissions, Up: administration-issues C.5.4.5 What to Do If MySQL Keeps Crashing .......................................... Each MySQL version is tested on many platforms before it is released. This doesn't mean that there are no bugs in MySQL, but if there are bugs, they should be very few and can be hard to find. If you have a problem, it always helps if you try to find out exactly what crashes your system, because you have a much better chance of getting the problem fixed quickly. First, you should try to find out whether the problem is that the *Note `mysqld': mysqld. server dies or whether your problem has to do with your client. You can check how long your *Note `mysqld': mysqld. server has been up by executing *Note `mysqladmin version': mysqladmin. If *Note `mysqld': mysqld. has died and restarted, you may find the reason by looking in the server's error log. See *Note error-log::. On some systems, you can find in the error log a stack trace of where *Note `mysqld': mysqld. died that you can resolve with the `resolve_stack_dump' program. See MySQL Internals: Porting (http://forge.mysql.com/wiki/MySQL_Internals_Porting). Note that the variable values written in the error log may not always be 100% correct. Many server crashes are caused by corrupted data files or index files. MySQL updates the files on disk with the `write()' system call after every SQL statement and before the client is notified about the result. (This is not true if you are running with `--delay-key-write', in which case data files are written but not index files.) This means that data file contents are safe even if *Note `mysqld': mysqld. crashes, because the operating system ensures that the unflushed data is written to disk. You can force MySQL to flush everything to disk after every SQL statement by starting *Note `mysqld': mysqld. with the `--flush' option. The preceding means that normally you should not get corrupted tables unless one of the following happens: * The MySQL server or the server host was killed in the middle of an update. * You have found a bug in *Note `mysqld': mysqld. that caused it to die in the middle of an update. * Some external program is manipulating data files or index files at the same time as *Note `mysqld': mysqld. without locking the table properly. * You are running many *Note `mysqld': mysqld. servers using the same data directory on a system that doesn't support good file system locks (normally handled by the `lockd' lock manager), or you are running multiple servers with external locking disabled. * You have a crashed data file or index file that contains very corrupt data that confused *Note `mysqld': mysqld. * You have found a bug in the data storage code. This isn't likely, but it is at least possible. In this case, you can try to change the storage engine to another engine by using *Note `ALTER TABLE': alter-table. on a repaired copy of the table. Because it is very difficult to know why something is crashing, first try to check whether things that work for others crash for you. Please try the following things: * Stop the *Note `mysqld': mysqld. server with *Note `mysqladmin shutdown': mysqladmin, run *Note `myisamchk --silent --force */*.MYI': myisamchk. from the data directory to check all `MyISAM' tables, and restart *Note `mysqld': mysqld. This ensures that you are running from a clean state. See *Note server-administration::. * Start *Note `mysqld': mysqld. with the general query log enabled (see *Note query-log::). Then try to determine from the information written to the log whether some specific query kills the server. About 95% of all bugs are related to a particular query. Normally, this is one of the last queries in the log file just before the server restarts. See *Note query-log::. If you can repeatedly kill MySQL with a specific query, even when you have checked all tables just before issuing it, then you have been able to locate the bug and should submit a bug report for it. See *Note bug-reports::. * Try to make a test case that we can use to repeat the problem. See MySQL Internals: Porting (http://forge.mysql.com/wiki/MySQL_Internals_Porting). * Try running the tests in the `mysql-test' directory and the MySQL benchmarks. See *Note mysql-test-suite::. They should test MySQL rather well. You can also add code to the benchmarks that simulates your application. The benchmarks can be found in the `sql-bench' directory in a source distribution or, for a binary distribution, in the `sql-bench' directory under your MySQL installation directory. * Try the `fork_big.pl' script. (It is located in the `tests' directory of source distributions.) * If you configure MySQL for debugging, it is much easier to gather information about possible errors if something goes wrong. Configuring MySQL for debugging causes a safe memory allocator to be included that can find some errors. It also provides a lot of output about what is happening. Reconfigure MySQL with the `--with-debug' or `--with-debug=full' option to `configure' and then recompile. See MySQL Internals: Porting (http://forge.mysql.com/wiki/MySQL_Internals_Porting). * Make sure that you have applied the latest patches for your operating system. * Use the `--skip-external-locking' option to *Note `mysqld': mysqld. On some systems, the `lockd' lock manager does not work properly; the `--skip-external-locking' option tells *Note `mysqld': mysqld. not to use external locking. (This means that you cannot run two *Note `mysqld': mysqld. servers on the same data directory and that you must be careful if you use *Note `myisamchk': myisamchk. Nevertheless, it may be instructive to try the option as a test.) * Have you tried *Note `mysqladmin -u root processlist': mysqladmin. when *Note `mysqld': mysqld. appears to be running but not responding? Sometimes *Note `mysqld': mysqld. is not comatose even though you might think so. The problem may be that all connections are in use, or there may be some internal lock problem. *Note `mysqladmin -u root processlist': mysqladmin. usually is able to make a connection even in these cases, and can provide useful information about the current number of connections and their status. * Run the command *Note `mysqladmin -i 5 status': mysqladmin. or *Note `mysqladmin -i 5 -r status': mysqladmin. in a separate window to produce statistics while you run your other queries. * Try the following: 1. Start *Note `mysqld': mysqld. from `gdb' (or another debugger). See MySQL Internals: Porting (http://forge.mysql.com/wiki/MySQL_Internals_Porting). 2. Run your test scripts. 3. Print the backtrace and the local variables at the three lowest levels. In `gdb', you can do this with the following commands when *Note `mysqld': mysqld. has crashed inside `gdb': backtrace info local up info local up info local With `gdb', you can also examine which threads exist with `info threads' and switch to a specific thread with `thread N', where N is the thread ID. * Try to simulate your application with a Perl script to force MySQL to crash or misbehave. * Send a normal bug report. See *Note bug-reports::. Be even more detailed than usual. Because MySQL works for many people, it may be that the crash results from something that exists only on your computer (for example, an error that is related to your particular system libraries). * If you have a problem with tables containing dynamic-length rows and you are using only *Note `VARCHAR': char. columns (not *Note `BLOB': blob. or *Note `TEXT': blob. columns), you can try to change all *Note `VARCHAR': char. to *Note `CHAR': char. with *Note `ALTER TABLE': alter-table. This forces MySQL to use fixed-size rows. Fixed-size rows take a little extra space, but are much more tolerant to corruption. The current dynamic row code has been in use for several years with very few problems, but dynamic-length rows are by nature more prone to errors, so it may be a good idea to try this strategy to see whether it helps. * Do not rule out your server hardware when diagnosing problems. Defective hardware can be the cause of data corruption. Particular attention should be paid to your memory and disk subsystems when troubleshooting hardware.  File: manual.info, Node: full-disk, Next: temporary-files, Prev: crashing, Up: administration-issues C.5.4.6 How MySQL Handles a Full Disk ..................................... This section describes how MySQL responds to disk-full errors (such as `no space left on device'), and to quota-exceeded errors (such as `write failed' or `user block limit reached'). This section is relevant for writes to `MyISAM' tables. It also applies for writes to binary log files and binary log index file, except that references to `row' and `record' should be understood to mean `event.' When a disk-full condition occurs, MySQL does the following: * It checks once every minute to see whether there is enough space to write the current row. If there is enough space, it continues as if nothing had happened. * Every 10 minutes it writes an entry to the log file, warning about the disk-full condition. To alleviate the problem, you can take the following actions: * To continue, you only have to free enough disk space to insert all records. * To abort the thread, you must use *Note `mysqladmin kill': mysqladmin. The thread is aborted the next time it checks the disk (in one minute). * Other threads might be waiting for the table that caused the disk-full condition. If you have several `locked' threads, killing the one thread that is waiting on the disk-full condition enables the other threads to continue. Exceptions to the preceding behavior are when you use *Note `REPAIR TABLE': repair-table. or *Note `OPTIMIZE TABLE': optimize-table. or when the indexes are created in a batch after *Note `LOAD DATA INFILE': load-data. or after an *Note `ALTER TABLE': alter-table. statement. All of these statements may create large temporary files that, if left to themselves, would cause big problems for the rest of the system. If the disk becomes full while MySQL is doing any of these operations, it removes the big temporary files and mark the table as crashed. The exception is that for *Note `ALTER TABLE': alter-table, the old table is left unchanged.  File: manual.info, Node: temporary-files, Next: problems-with-mysql-sock, Prev: full-disk, Up: administration-issues C.5.4.7 Where MySQL Stores Temporary Files .......................................... On Unix, MySQL uses the value of the `TMPDIR' environment variable as the path name of the directory in which to store temporary files. If `TMPDIR' is not set, MySQL uses the system default, which is usually `/tmp', `/var/tmp', or `/usr/tmp'. On Windows, Netware and OS2, MySQL checks in order the values of the `TMPDIR', `TEMP', and `TMP' environment variables. For the first one found to be set, MySQL uses it and does not check those remaining. If none of `TMPDIR', `TEMP', or `TMP' are set, MySQL uses the Windows system default, which is usually `C:\windows\temp\'. If the file system containing your temporary file directory is too small, you can use the `--tmpdir' option to *Note `mysqld': mysqld. to specify a directory in a file system where you have enough space. In MySQL 5.1, the `--tmpdir' option can be set to a list of several paths that are used in round-robin fashion. Paths should be separated by colon characters (``:'') on Unix and semicolon characters (``;'') on Windows, NetWare, and OS/2. *Note*: To spread the load effectively, these paths should be located on different _physical_ disks, not different partitions of the same disk. If the MySQL server is acting as a replication slave, you should not set `--tmpdir' to point to a directory on a memory-based file system or to a directory that is cleared when the server host restarts. A replication slave needs some of its temporary files to survive a machine restart so that it can replicate temporary tables or *Note `LOAD DATA INFILE': load-data. operations. If files in the temporary file directory are lost when the server restarts, replication fails. MySQL creates all temporary files as hidden files. This ensures that the temporary files are removed if *Note `mysqld': mysqld. is terminated. The disadvantage of using hidden files is that you do not see a big temporary file that fills up the file system in which the temporary file directory is located. When sorting (`ORDER BY' or `GROUP BY'), MySQL normally uses one or two temporary files. The maximum disk space required is determined by the following expression: (length of what is sorted + sizeof(row pointer)) * number of matched rows * 2 The row pointer size is usually four bytes, but may grow in the future for really big tables. For some *Note `SELECT': select. queries, MySQL also creates temporary SQL tables. These are not hidden and have names of the form `SQL_*'. *Note `ALTER TABLE': alter-table. creates a temporary table in the same directory as the original table.  File: manual.info, Node: problems-with-mysql-sock, Next: timezone-problems, Prev: temporary-files, Up: administration-issues C.5.4.8 How to Protect or Change the MySQL Unix Socket File ........................................................... The default location for the Unix socket file that the server uses for communication with local clients is `/tmp/mysql.sock'. (For some distribution formats, the directory might be different, such as `/var/lib/mysql' for RPMs.) On some versions of Unix, anyone can delete files in the `/tmp' directory or other similar directories used for temporary files. If the socket file is located in such a directory on your system, this might cause problems. On most versions of Unix, you can protect your `/tmp' directory so that files can be deleted only by their owners or the superuser (`root'). To do this, set the `sticky' bit on the `/tmp' directory by logging in as `root' and using the following command: shell> chmod +t /tmp You can check whether the `sticky' bit is set by executing `ls -ld /tmp'. If the last permission character is `t', the bit is set. Another approach is to change the place where the server creates the Unix socket file. If you do this, you should also let client programs know the new location of the file. You can specify the file location in several ways: * Specify the path in a global or local option file. For example, put the following lines in `/etc/my.cnf': [mysqld] socket=/path/to/socket [client] socket=/path/to/socket See *Note option-files::. * Specify a `--socket' option on the command line to *Note `mysqld_safe': mysqld-safe. and when you run client programs. * Set the `MYSQL_UNIX_PORT' environment variable to the path of the Unix socket file. * Recompile MySQL from source to use a different default Unix socket file location. Define the path to the file with the `--with-unix-socket-path' option when you run `configure'. See *Note source-configuration-options::. You can test whether the new socket location works by attempting to connect to the server with this command: shell> mysqladmin --socket=/path/to/socket version  File: manual.info, Node: timezone-problems, Prev: problems-with-mysql-sock, Up: administration-issues C.5.4.9 Time Zone Problems .......................... If you have a problem with `SELECT NOW()' returning values in UTC and not your local time, you have to tell the server your current time zone. The same applies if `UNIX_TIMESTAMP()' returns the wrong value. This should be done for the environment in which the server runs; for example, in *Note `mysqld_safe': mysqld-safe. or *Note `mysql.server': mysql-server. See *Note environment-variables::. You can set the time zone for the server with the `--timezone=TIMEZONE_NAME' option to *Note `mysqld_safe': mysqld-safe. You can also set it by setting the `TZ' environment variable before you start *Note `mysqld': mysqld. The permissible values for `--timezone' or `TZ' are system dependent. Consult your operating system documentation to see what values are acceptable.  File: manual.info, Node: query-issues, Next: optimizer-issues, Prev: administration-issues, Up: problems C.5.5 Query-Related Issues -------------------------- * Menu: * case-sensitivity:: Case Sensitivity in String Searches * using-date:: Problems Using `DATE' Columns * problems-with-null:: Problems with `NULL' Values * problems-with-alias:: Problems with Column Aliases * non-transactional-tables:: Rollback Failure for Nontransactional Tables * deleting-from-related-tables:: Deleting Rows from Related Tables * no-matching-rows:: Solving Problems with No Matching Rows * problems-with-float:: Problems with Floating-Point Values  File: manual.info, Node: case-sensitivity, Next: using-date, Prev: query-issues, Up: query-issues C.5.5.1 Case Sensitivity in String Searches ........................................... For nonbinary strings (*Note `CHAR': char, *Note `VARCHAR': char, *Note `TEXT': blob.), string searches use the collation of the comparison operands. For binary strings (*Note `BINARY': binary-varbinary, *Note `VARBINARY': binary-varbinary, *Note `BLOB': blob.), comparisons use the numeric values of the bytes in the operands; this means that for alphabetic characters, comparisons will be case sensitive. A comparison between a nonbinary string and binary string is treated as a comparison of binary strings. Simple comparison operations (`>=, >, =, <, <=', sorting, and grouping) are based on each character's `sort value.' Characters with the same sort value are treated as the same character. For example, if ``e'' and ``e''' have the same sort value in a given collation, they compare as equal. The default character set and collation are `latin1' and `latin1_swedish_ci', so nonbinary string comparisons are case insensitive by default. This means that if you search with `COL_NAME LIKE 'a%'', you get all column values that start with `A' or `a'. To make this search case sensitive, make sure that one of the operands has a case sensitive or binary collation. For example, if you are comparing a column and a string that both have the `latin1' character set, you can use the `COLLATE' operator to cause either operand to have the `latin1_general_cs' or `latin1_bin' collation: COL_NAME COLLATE latin1_general_cs LIKE 'a%' COL_NAME LIKE 'a%' COLLATE latin1_general_cs COL_NAME COLLATE latin1_bin LIKE 'a%' COL_NAME LIKE 'a%' COLLATE latin1_bin If you want a column always to be treated in case-sensitive fashion, declare it with a case sensitive or binary collation. See *Note create-table::. To cause a case-sensitive comparison of nonbinary strings to be case insensitive, use `COLLATE' to name a case-insensitive collation. The strings in the following example normally are case sensitive, but `COLLATE' changes the comparison to be case insensitive: mysql> SET @s1 = 'MySQL' COLLATE latin1_bin, -> @s2 = 'mysql' COLLATE latin1_bin; mysql> SELECT @s1 = @s2; +-----------+ | @s1 = @s2 | +-----------+ | 0 | +-----------+ mysql> SELECT @s1 COLLATE latin1_swedish_ci = @s2; +-------------------------------------+ | @s1 COLLATE latin1_swedish_ci = @s2 | +-------------------------------------+ | 1 | +-------------------------------------+ A binary string is case sensitive in comparisons. To compare the string as case insensitive, convert it to a nonbinary string and use `COLLATE' to name a case-insensitive collation: mysql> SET @s = BINARY 'MySQL'; mysql> SELECT @s = 'mysql'; +--------------+ | @s = 'mysql' | +--------------+ | 0 | +--------------+ mysql> SELECT CONVERT(@s USING latin1) COLLATE latin1_swedish_ci = 'mysql'; +--------------------------------------------------------------+ | CONVERT(@s USING latin1) COLLATE latin1_swedish_ci = 'mysql' | +--------------------------------------------------------------+ | 1 | +--------------------------------------------------------------+ To determine whether a value will compare as a nonbinary or binary string, use the `COLLATION()' function. This example shows that `VERSION()' returns a string that has a case-insensitive collation, so comparisons are case insensitive: mysql> SELECT COLLATION(VERSION()); +----------------------+ | COLLATION(VERSION()) | +----------------------+ | utf8_general_ci | +----------------------+ For binary strings, the collation value is `binary', so comparisons will be case sensitive. One context in which you will see `binary' is for compression and encryption functions, which return binary strings as a general rule: string: mysql> SELECT COLLATION(ENCRYPT('x')), COLLATION(SHA1('x')); +-------------------------+----------------------+ | COLLATION(ENCRYPT('x')) | COLLATION(SHA1('x')) | +-------------------------+----------------------+ | binary | binary | +-------------------------+----------------------+  File: manual.info, Node: using-date, Next: problems-with-null, Prev: case-sensitivity, Up: query-issues C.5.5.2 Problems Using `DATE' Columns ..................................... The format of a *Note `DATE': datetime. value is `'YYYY-MM-DD''. According to standard SQL, no other format is permitted. You should use this format in *Note `UPDATE': update. expressions and in the `WHERE' clause of *Note `SELECT': select. statements. For example: mysql> SELECT * FROM TBL_NAME WHERE date >= '2003-05-05'; As a convenience, MySQL automatically converts a date to a number if the date is used in a numeric context (and vice versa). It is also smart enough to permit a `relaxed' string form when updating and in a `WHERE' clause that compares a date to a *Note `TIMESTAMP': datetime, *Note `DATE': datetime, or *Note `DATETIME': datetime. column. (`Relaxed form' means that any punctuation character may be used as the separator between parts. For example, `'2004-08-15'' and `'2004#08#15'' are equivalent.) MySQL can also convert a string containing no separators (such as `'20040815''), provided it makes sense as a date. When you compare a *Note `DATE': datetime, *Note `TIME': time, *Note `DATETIME': datetime, or *Note `TIMESTAMP': datetime. to a constant string with the `<', `<=', `=', `>=', `>', or `BETWEEN' operators, MySQL normally converts the string to an internal long integer for faster comparison (and also for a bit more `relaxed' string checking). However, this conversion is subject to the following exceptions: * When you compare two columns * When you compare a *Note `DATE': datetime, *Note `TIME': time, *Note `DATETIME': datetime, or *Note `TIMESTAMP': datetime. column to an expression * When you use any other comparison method than those just listed, such as `IN' or `STRCMP()'. For these exceptional cases, the comparison is done by converting the objects to strings and performing a string comparison. To keep things safe, assume that strings are compared as strings and use the appropriate string functions if you want to compare a temporal value to a string. The special date `'0000-00-00'' can be stored and retrieved as `'0000-00-00'.' When using a `'0000-00-00'' date through MyODBC, it is automatically converted to `NULL' in MyODBC 2.50.12 and above, because ODBC can't handle this kind of date. Because MySQL performs the conversions described above, the following statements work: mysql> INSERT INTO TBL_NAME (idate) VALUES (19970505); mysql> INSERT INTO TBL_NAME (idate) VALUES ('19970505'); mysql> INSERT INTO TBL_NAME (idate) VALUES ('97-05-05'); mysql> INSERT INTO TBL_NAME (idate) VALUES ('1997.05.05'); mysql> INSERT INTO TBL_NAME (idate) VALUES ('1997 05 05'); mysql> INSERT INTO TBL_NAME (idate) VALUES ('0000-00-00'); mysql> SELECT idate FROM TBL_NAME WHERE idate >= '1997-05-05'; mysql> SELECT idate FROM TBL_NAME WHERE idate >= 19970505; mysql> SELECT MOD(idate,100) FROM TBL_NAME WHERE idate >= 19970505; mysql> SELECT idate FROM TBL_NAME WHERE idate >= '19970505'; However, the following does not work: mysql> SELECT idate FROM TBL_NAME WHERE STRCMP(idate,'20030505')=0; `STRCMP()' is a string function, so it converts `idate' to a string in `'YYYY-MM-DD'' format and performs a string comparison. It does not convert `'20030505'' to the date `'2003-05-05'' and perform a date comparison. If you are using the `ALLOW_INVALID_DATES' SQL mode, MySQL permits you to store dates that are given only limited checking: MySQL requires only that the day is in the range from 1 to 31 and the month is in the range from 1 to 12. This makes MySQL very convenient for Web applications where you obtain year, month, and day in three different fields and you want to store exactly what the user inserted (without date validation). If you are not using the `NO_ZERO_IN_DATE' SQL mode, the day or month part can be zero. This is convenient if you want to store a birthdate in a *Note `DATE': datetime. column and you know only part of the date. If you are not using the `NO_ZERO_DATE' SQL mode, MySQL also permits you to store `'0000-00-00'' as a `dummy date.' This is in some cases more convenient than using `NULL' values. If the date cannot be converted to any reasonable value, a `0' is stored in the *Note `DATE': datetime. column, which is retrieved as `'0000-00-00''. This is both a speed and a convenience issue. We believe that the database server's responsibility is to retrieve the same date you stored (even if the data was not logically correct in all cases). We think it is up to the application and not the server to check the dates. If you want MySQL to check all dates and accept only legal dates (unless overridden by IGNORE), you should set `sql_mode' to `"NO_ZERO_IN_DATE,NO_ZERO_DATE"'.  File: manual.info, Node: problems-with-null, Next: problems-with-alias, Prev: using-date, Up: query-issues C.5.5.3 Problems with `NULL' Values ................................... The concept of the `NULL' value is a common source of confusion for newcomers to SQL, who often think that `NULL' is the same thing as an empty string `'''. This is not the case. For example, the following statements are completely different: mysql> INSERT INTO my_table (phone) VALUES (NULL); mysql> INSERT INTO my_table (phone) VALUES (''); Both statements insert a value into the `phone' column, but the first inserts a `NULL' value and the second inserts an empty string. The meaning of the first can be regarded as `phone number is not known' and the meaning of the second can be regarded as `the person is known to have no phone, and thus no phone number.' To help with `NULL' handling, you can use the `IS NULL' and `IS NOT NULL' operators and the `IFNULL()' function. In SQL, the `NULL' value is never true in comparison to any other value, even `NULL'. An expression that contains `NULL' always produces a `NULL' value unless otherwise indicated in the documentation for the operators and functions involved in the expression. All columns in the following example return `NULL': mysql> SELECT NULL, 1+NULL, CONCAT('Invisible',NULL); If you want to search for column values that are `NULL', you cannot use an `expr = NULL' test. The following statement returns no rows, because `expr = NULL' is never true for any expression: mysql> SELECT * FROM my_table WHERE phone = NULL; To look for `NULL' values, you must use the `IS NULL' test. The following statements show how to find the `NULL' phone number and the empty phone number: mysql> SELECT * FROM my_table WHERE phone IS NULL; mysql> SELECT * FROM my_table WHERE phone = ''; See *Note working-with-null::, for additional information and examples. You can add an index on a column that can have `NULL' values if you are using the `MyISAM', `InnoDB', or `MEMORY' storage engine. Otherwise, you must declare an indexed column `NOT NULL', and you cannot insert `NULL' into the column. When reading data with *Note `LOAD DATA INFILE': load-data, empty or missing columns are updated with `'''. If you want a `NULL' value in a column, you should use `\N' in the data file. The literal word ``NULL'' may also be used under some circumstances. See *Note load-data::. When using `DISTINCT', `GROUP BY', or `ORDER BY', all `NULL' values are regarded as equal. When using `ORDER BY', `NULL' values are presented first, or last if you specify `DESC' to sort in descending order. Aggregate (summary) functions such as `COUNT()', `MIN()', and `SUM()' ignore `NULL' values. The exception to this is `COUNT(*)', which counts rows and not individual column values. For example, the following statement produces two counts. The first is a count of the number of rows in the table, and the second is a count of the number of non-`NULL' values in the `age' column: mysql> SELECT COUNT(*), COUNT(age) FROM person; For some data types, MySQL handles `NULL' values specially. If you insert `NULL' into a *Note `TIMESTAMP': datetime. column, the current date and time is inserted. If you insert `NULL' into an integer or floating-point column that has the `AUTO_INCREMENT' attribute, the next number in the sequence is inserted.  File: manual.info, Node: problems-with-alias, Next: non-transactional-tables, Prev: problems-with-null, Up: query-issues C.5.5.4 Problems with Column Aliases .................................... An alias can be used in a query select list to give a column a different name. You can use the alias in `GROUP BY', `ORDER BY', or `HAVING' clauses to refer to the column: SELECT SQRT(a*b) AS root FROM TBL_NAME GROUP BY root HAVING root > 0; SELECT id, COUNT(*) AS cnt FROM TBL_NAME GROUP BY id HAVING cnt > 0; SELECT id AS 'Customer identity' FROM TBL_NAME; Standard SQL disallows references to column aliases in a `WHERE' clause. This restriction is imposed because when the `WHERE' clause is evaluated, the column value may not yet have been determined. For example, the following query is illegal: SELECT id, COUNT(*) AS cnt FROM TBL_NAME WHERE cnt > 0 GROUP BY id; The `WHERE' clause determines which rows should be included in the `GROUP BY' clause, but it refers to the alias of a column value that is not known until after the rows have been selected, and grouped by the `GROUP BY'. In the select list of a query, a quoted column alias can be specified using identifier or string quoting characters: SELECT 1 AS `one`, 2 AS 'two'; Elsewhere in the statement, quoted references to the alias must use identifier quoting or the reference is treated as a string literal. For example, this statement groups by the values in column `id', referenced using the alias ``a`': SELECT id AS 'a', COUNT(*) AS cnt FROM TBL_NAME GROUP BY `a`; But this statement groups by the literal string `'a'' and will not work as expected: SELECT id AS 'a', COUNT(*) AS cnt FROM TBL_NAME GROUP BY 'a';  File: manual.info, Node: non-transactional-tables, Next: deleting-from-related-tables, Prev: problems-with-alias, Up: query-issues C.5.5.5 Rollback Failure for Nontransactional Tables .................................................... If you receive the following message when trying to perform a *Note `ROLLBACK': commit, it means that one or more of the tables you used in the transaction do not support transactions: Warning: Some non-transactional changed tables couldn't be rolled back These nontransactional tables are not affected by the *Note `ROLLBACK': commit. statement. If you were not deliberately mixing transactional and nontransactional tables within the transaction, the most likely cause for this message is that a table you thought was transactional actually is not. This can happen if you try to create a table using a transactional storage engine that is not supported by your *Note `mysqld': mysqld. server (or that was disabled with a startup option). If *Note `mysqld': mysqld. doesn't support a storage engine, it instead creates the table as a `MyISAM' table, which is nontransactional. You can check the storage engine for a table by using either of these statements: SHOW TABLE STATUS LIKE 'TBL_NAME'; SHOW CREATE TABLE TBL_NAME; See *Note show-table-status::, and *Note show-create-table::. You can check which storage engines your *Note `mysqld': mysqld. server supports by using this statement: SHOW ENGINES; You can also use the following statement, and check the value of the variable that is associated with the storage engine in which you are interested: SHOW VARIABLES LIKE 'have_%'; For example, to determine whether the `InnoDB' storage engine is available, check the value of the `have_innodb' variable. See *Note show-engines::, and *Note show-variables::.  File: manual.info, Node: deleting-from-related-tables, Next: no-matching-rows, Prev: non-transactional-tables, Up: query-issues C.5.5.6 Deleting Rows from Related Tables ......................................... If the total length of the *Note `DELETE': delete. statement for `related_table' is more than 1MB (the default value of the `max_allowed_packet' system variable), you should split it into smaller parts and execute multiple *Note `DELETE': delete. statements. You probably get the fastest *Note `DELETE': delete. by specifying only 100 to 1,000 `related_column' values per statement if the `related_column' is indexed. If the `related_column' isn't indexed, the speed is independent of the number of arguments in the `IN' clause.  File: manual.info, Node: no-matching-rows, Next: problems-with-float, Prev: deleting-from-related-tables, Up: query-issues C.5.5.7 Solving Problems with No Matching Rows .............................................. If you have a complicated query that uses many tables but that doesn't return any rows, you should use the following procedure to find out what is wrong: 1. Test the query with *Note `EXPLAIN': explain. to check whether you can find something that is obviously wrong. See *Note explain::. 2. Select only those columns that are used in the `WHERE' clause. 3. Remove one table at a time from the query until it returns some rows. If the tables are large, it is a good idea to use `LIMIT 10' with the query. 4. Issue a *Note `SELECT': select. for the column that should have matched a row against the table that was last removed from the query. 5. If you are comparing *Note `FLOAT': numeric-types. or *Note `DOUBLE': numeric-types. columns with numbers that have decimals, you can't use equality (`=') comparisons. This problem is common in most computer languages because not all floating-point values can be stored with exact precision. In some cases, changing the *Note `FLOAT': numeric-types. to a *Note `DOUBLE': numeric-types. fixes this. See *Note problems-with-float::. 6. If you still can't figure out what is wrong, create a minimal test that can be run with `mysql test < query.sql' that shows your problems. You can create a test file by dumping the tables with *Note `mysqldump --quick db_name TBL_NAME_1 ... TBL_NAME_N > query.sql': mysqldump. Open the file in an editor, remove some insert lines (if there are more than needed to demonstrate the problem), and add your *Note `SELECT': select. statement at the end of the file. Verify that the test file demonstrates the problem by executing these commands: shell> mysqladmin create test2 shell> mysql test2 < query.sql Attach the test file to a bug report, which you can file using the instructions in *Note bug-reports::.  File: manual.info, Node: problems-with-float, Prev: no-matching-rows, Up: query-issues C.5.5.8 Problems with Floating-Point Values ........................................... Floating-point numbers sometimes cause confusion because they are approximate and not stored as exact values. A floating-point value as written in an SQL statement may not be the same as the value represented internally. Attempts to treat floating-point values as exact in comparisons may lead to problems. They are also subject to platform or implementation dependencies. The *Note `FLOAT': numeric-types. and *Note `DOUBLE': numeric-types. data types are subject to these issues. For *Note `DECIMAL': numeric-types. columns, MySQL performs operations with a precision of 65 decimal digits, which should solve most common inaccuracy problems. The following example uses *Note `DOUBLE': numeric-types. to demonstrate how calculations that are done using floating-point operations are subject to floating-point error. mysql> CREATE TABLE t1 (i INT, d1 DOUBLE, d2 DOUBLE); mysql> INSERT INTO t1 VALUES (1, 101.40, 21.40), (1, -80.00, 0.00), -> (2, 0.00, 0.00), (2, -13.20, 0.00), (2, 59.60, 46.40), -> (2, 30.40, 30.40), (3, 37.00, 7.40), (3, -29.60, 0.00), -> (4, 60.00, 15.40), (4, -10.60, 0.00), (4, -34.00, 0.00), -> (5, 33.00, 0.00), (5, -25.80, 0.00), (5, 0.00, 7.20), -> (6, 0.00, 0.00), (6, -51.40, 0.00); mysql> SELECT i, SUM(d1) AS a, SUM(d2) AS b -> FROM t1 GROUP BY i HAVING a <> b; +------+-------+------+ | i | a | b | +------+-------+------+ | 1 | 21.4 | 21.4 | | 2 | 76.8 | 76.8 | | 3 | 7.4 | 7.4 | | 4 | 15.4 | 15.4 | | 5 | 7.2 | 7.2 | | 6 | -51.4 | 0 | +------+-------+------+ The result is correct. Although the first five records look like they should not satisfy the comparison (the values of `a' and `b' do not appear to be different), they may do so because the difference between the numbers shows up around the tenth decimal or so, depending on factors such as computer architecture or the compiler version or optimization level. For example, different CPUs may evaluate floating-point numbers differently. If columns `d1' and `d2' had been defined as *Note `DECIMAL': numeric-types. rather than *Note `DOUBLE': numeric-types, the result of the *Note `SELECT': select. query would have contained only one row--the last one shown above. The correct way to do floating-point number comparison is to first decide on an acceptable tolerance for differences between the numbers and then do the comparison against the tolerance value. For example, if we agree that floating-point numbers should be regarded the same if they are same within a precision of one in ten thousand (0.0001), the comparison should be written to find differences larger than the tolerance value: mysql> SELECT i, SUM(d1) AS a, SUM(d2) AS b FROM t1 -> GROUP BY i HAVING ABS(a - b) > 0.0001; +------+-------+------+ | i | a | b | +------+-------+------+ | 6 | -51.4 | 0 | +------+-------+------+ 1 row in set (0.00 sec) Conversely, to get rows where the numbers are the same, the test should find differences within the tolerance value: mysql> SELECT i, SUM(d1) AS a, SUM(d2) AS b FROM t1 -> GROUP BY i HAVING ABS(a - b) <= 0.0001; +------+------+------+ | i | a | b | +------+------+------+ | 1 | 21.4 | 21.4 | | 2 | 76.8 | 76.8 | | 3 | 7.4 | 7.4 | | 4 | 15.4 | 15.4 | | 5 | 7.2 | 7.2 | +------+------+------+ 5 rows in set (0.03 sec) Floating-point values are subject to platform or implementation dependencies. Suppose that you execute the following statements: CREATE TABLE t1(c1 FLOAT(53,0), c2 FLOAT(53,0)); INSERT INTO t1 VALUES('1e+52','-1e+52'); SELECT * FROM t1; On some platforms, the `SELECT' statement returns `inf' and `-inf'. Other others, it returns `0' and `-0'. An implication of the preceding issues is that if you attempt to create a replication slave by dumping table contents with *Note `mysqldump': mysqldump. on the master and reloading the dump file into the slave, tables containing floating-point columns might differ between the two hosts.  File: manual.info, Node: optimizer-issues, Next: table-definition-issues, Prev: query-issues, Up: problems C.5.6 Optimizer-Related Issues ------------------------------ MySQL uses a cost-based optimizer to determine the best way to resolve a query. In many cases, MySQL can calculate the best possible query plan, but sometimes MySQL doesn't have enough information about the data at hand and has to make `educated' guesses about the data. For the cases when MySQL does not do the "right" thing, tools that you have available to help MySQL are: * Use the *Note `EXPLAIN': explain. statement to get information about how MySQL processes a query. To use it, just add the keyword *Note `EXPLAIN': explain. to the front of your *Note `SELECT': select. statement: mysql> EXPLAIN SELECT * FROM t1, t2 WHERE t1.i = t2.i; *Note `EXPLAIN': explain. is discussed in more detail in *Note explain::. * Use `ANALYZE TABLE TBL_NAME' to update the key distributions for the scanned table. See *Note analyze-table::. * Use `FORCE INDEX' for the scanned table to tell MySQL that table scans are very expensive compared to using the given index: SELECT * FROM t1, t2 FORCE INDEX (index_for_column) WHERE t1.col_name=t2.col_name; `USE INDEX' and `IGNORE INDEX' may also be useful. See *Note index-hints::. * Global and table-level `STRAIGHT_JOIN'. See *Note select::. * You can tune global or thread-specific system variables. For example, Start *Note `mysqld': mysqld. with the `--max-seeks-for-key=1000' option or use `SET max_seeks_for_key=1000' to tell the optimizer to assume that no key scan causes more than 1,000 key seeks. See *Note server-system-variables::.  File: manual.info, Node: table-definition-issues, Next: bugs, Prev: optimizer-issues, Up: problems C.5.7 Table Definition-Related Issues ------------------------------------- * Menu: * alter-table-problems:: Problems with `ALTER TABLE' * temporary-table-problems:: `TEMPORARY' Table Problems  File: manual.info, Node: alter-table-problems, Next: temporary-table-problems, Prev: table-definition-issues, Up: table-definition-issues C.5.7.1 Problems with `ALTER TABLE' ................................... If you get a duplicate-key error when using *Note `ALTER TABLE': alter-table. to change the character set or collation of a character column, the cause is either that the new column collation maps two keys to the same value or that the table is corrupted. In the latter case, you should run *Note `REPAIR TABLE': repair-table. on the table. If *Note `ALTER TABLE': alter-table. dies with the following error, the problem may be that MySQL crashed during an earlier *Note `ALTER TABLE': alter-table. operation and there is an old table named `A-XXX' or `B-XXX' lying around: Error on rename of './database/name.frm' to './database/B-XXX.frm' (Errcode: 17) In this case, go to the MySQL data directory and delete all files that have names starting with `A-' or `B-'. (You may want to move them elsewhere instead of deleting them.) *Note `ALTER TABLE': alter-table. works in the following way: * Create a new table named `A-XXX' with the requested structural changes. * Copy all rows from the original table to `A-XXX'. * Rename the original table to `B-XXX'. * Rename `A-XXX' to your original table name. * Delete `B-XXX'. If something goes wrong with the renaming operation, MySQL tries to undo the changes. If something goes seriously wrong (although this shouldn't happen), MySQL may leave the old table as `B-XXX'. A simple rename of the table files at the system level should get your data back. If you use *Note `ALTER TABLE': alter-table. on a transactional table or if you are using Windows or OS/2, *Note `ALTER TABLE': alter-table. unlocks the table if you had done a *Note `LOCK TABLE': lock-tables. on it. This is done because `InnoDB' and these operating systems cannot drop a table that is in use.  File: manual.info, Node: temporary-table-problems, Prev: alter-table-problems, Up: table-definition-issues C.5.7.2 `TEMPORARY' Table Problems .................................. The following list indicates limitations on the use of `TEMPORARY' tables: * A `TEMPORARY' table can only be of type `MEMORY', `MyISAM', `MERGE', or `InnoDB'. Temporary tables are not supported for MySQL Cluster. * You cannot refer to a `TEMPORARY' table more than once in the same query. For example, the following does not work: mysql> SELECT * FROM temp_table, temp_table AS t2; ERROR 1137: Can't reopen table: 'temp_table' This error also occurs if you refer to a temporary table multiple times in a stored function under different aliases, even if the references occur in different statements within the function. * The *Note `SHOW TABLES': show-tables. statement does not list `TEMPORARY' tables. * You cannot use `RENAME' to rename a `TEMPORARY' table. However, you can use *Note `ALTER TABLE': alter-table. instead: mysql> ALTER TABLE orig_name RENAME new_name; * There are known issues in using temporary tables with replication. See *Note replication-features::, for more information.  File: manual.info, Node: bugs, Prev: table-definition-issues, Up: problems C.5.8 Known Issues in MySQL --------------------------- This section lists known issues in recent versions of MySQL. For information about platform-specific issues, see the installation and porting instructions in *Note general-installation-issues::, and MySQL Internals: Porting (http://forge.mysql.com/wiki/MySQL_Internals_Porting). The following problems are known: * Subquery optimization for `IN' is not as effective as for `='. * Even if you use `lower_case_table_names=2' (which enables MySQL to remember the case used for databases and table names), MySQL does not remember the case used for database names for the function `DATABASE()' or within the various logs (on case-insensitive systems). * Dropping a `FOREIGN KEY' constraint doesn't work in replication because the constraint may have another name on the slave. * *Note `REPLACE': replace. (and *Note `LOAD DATA': load-data. with the *Note `REPLACE': replace. option) does not trigger `ON DELETE CASCADE'. * `DISTINCT' with `ORDER BY' doesn't work inside `GROUP_CONCAT()' if you don't use all and only those columns that are in the `DISTINCT' list. * If one user has a long-running transaction and another user drops a table that is updated in the transaction, there is small chance that the binary log may contain the *Note `DROP TABLE': drop-table. statement before the table is used in the transaction itself. We plan to fix this by having the *Note `DROP TABLE': drop-table. statement wait until the table is not being used in any transaction. * When inserting a big integer value (between 2^63 and 2^64-1) into a decimal or string column, it is inserted as a negative value because the number is evaluated in a signed integer context. * *Note `FLUSH TABLES WITH READ LOCK': flush. does not block *Note `COMMIT': commit. if the server is running without binary logging, which may cause a problem (of consistency between tables) when doing a full backup. * *Note `ANALYZE TABLE': analyze-table, *Note `OPTIMIZE TABLE': optimize-table, and *Note `REPAIR TABLE': repair-table. may cause problems on tables for which you are using *Note `INSERT DELAYED': insert-delayed. * Performing `LOCK TABLE ...' and `FLUSH TABLES ...' doesn't guarantee that there isn't a half-finished transaction in progress on the table. * Replication uses query-level logging: The master writes the executed queries to the binary log. This is a very fast, compact, and efficient logging method that works perfectly in most cases. It is possible for the data on the master and slave to become different if a query is designed in such a way that the data modification is nondeterministic (generally not a recommended practice, even outside of replication). For example: * *Note `CREATE TABLE ... SELECT': create-table-select. or *Note `INSERT ... SELECT': insert-select. statements that insert zero or `NULL' values into an `AUTO_INCREMENT' column. * *Note `DELETE': delete. if you are deleting rows from a table that has foreign keys with `ON DELETE CASCADE' properties. * *Note `REPLACE ... SELECT': replace, `INSERT IGNORE ... SELECT' if you have duplicate key values in the inserted data. *If and only if the preceding queries have no `ORDER BY' clause guaranteeing a deterministic order*. For example, for *Note `INSERT ... SELECT': insert-select. with no `ORDER BY', the *Note `SELECT': select. may return rows in a different order (which results in a row having different ranks, hence getting a different number in the `AUTO_INCREMENT' column), depending on the choices made by the optimizers on the master and slave. A query is optimized differently on the master and slave only if: * The table is stored using a different storage engine on the master than on the slave. (It is possible to use different storage engines on the master and slave. For example, you can use `InnoDB' on the master, but `MyISAM' on the slave if the slave has less available disk space.) * MySQL buffer sizes (`key_buffer_size', and so on) are different on the master and slave. * The master and slave run different MySQL versions, and the optimizer code differs between these versions. This problem may also affect database restoration using `mysqlbinlog|mysql'. The easiest way to avoid this problem is to add an `ORDER BY' clause to the aforementioned nondeterministic queries to ensure that the rows are always stored or modified in the same order. In future MySQL versions, we will automatically add an `ORDER BY' clause when needed. The following issues are known and will be fixed in due time: * Log file names are based on the server host name (if you don't specify a file name with the startup option). You have to use options such as `--log-bin=OLD_HOST_NAME-bin' if you change your host name to something else. Another option is to rename the old files to reflect your host name change (if these are binary logs, you need to edit the binary log index file and fix the binary log file names there as well). See *Note server-options::. * *Note `mysqlbinlog': mysqlbinlog. does not delete temporary files left after a *Note `LOAD DATA INFILE': load-data. statement. See *Note mysqlbinlog::. * `RENAME' doesn't work with `TEMPORARY' tables or tables used in a `MERGE' table. * Due to the way table format (`.frm') files are stored, you cannot use character 255 (`CHAR(255)') in table names, column names, or enumerations. This is scheduled to be fixed in version 5.1 when we implement new table definition format files. * When using `SET CHARACTER SET', you can't use translated characters in database, table, and column names. * You can't use ``_'' or ``%'' with `ESCAPE' in `LIKE ... ESCAPE'. * *Note `BLOB': blob. and *Note `TEXT': blob. values can't reliably be used in `GROUP BY', `ORDER BY' or `DISTINCT'. Only the first `max_sort_length' bytes are used when comparing *Note `BLOB': blob. values in these cases. The default value of `max_sort_length' is 1024 and can be changed at server startup time or at runtime. * Numeric calculations are done with *Note `BIGINT': numeric-types. or *Note `DOUBLE': numeric-types. (both are normally 64 bits long). Which precision you get depends on the function. The general rule is that bit functions are performed with *Note `BIGINT': numeric-types. precision, `IF()' and `ELT()' with *Note `BIGINT': numeric-types. or *Note `DOUBLE': numeric-types. precision, and the rest with *Note `DOUBLE': numeric-types. precision. You should try to avoid using unsigned long long values if they resolve to be larger than 63 bits (9223372036854775807) for anything other than bit fields. * You can have up to 255 *Note `ENUM': enum. and *Note `SET': set. columns in one table. * In `MIN()', `MAX()', and other aggregate functions, MySQL currently compares *Note `ENUM': enum. and *Note `SET': set. columns by their string value rather than by the string's relative position in the set. * *Note `mysqld_safe': mysqld-safe. redirects all messages from *Note `mysqld': mysqld. to the *Note `mysqld': mysqld. log. One problem with this is that if you execute *Note `mysqladmin refresh': mysqladmin. to close and reopen the log, `stdout' and `stderr' are still redirected to the old log. If you use the general query log extensively, you should edit *Note `mysqld_safe': mysqld-safe. to log to `HOST_NAME.err' instead of `HOST_NAME.log' so that you can easily reclaim the space for the old log by deleting it and executing *Note `mysqladmin refresh': mysqladmin. * In an *Note `UPDATE': update. statement, columns are updated from left to right. If you refer to an updated column, you get the updated value instead of the original value. For example, the following statement increments `KEY' by `2', *not* `1': mysql> UPDATE TBL_NAME SET KEY=KEY+1,KEY=KEY+1; * You can refer to multiple temporary tables in the same query, but you cannot refer to any given temporary table more than once. For example, the following doesn't work: mysql> SELECT * FROM temp_table, temp_table AS t2; ERROR 1137: Can't reopen table: 'temp_table' * The optimizer may handle `DISTINCT' differently when you are using `hidden' columns in a join than when you are not. In a join, hidden columns are counted as part of the result (even if they are not shown), whereas in normal queries, hidden columns don't participate in the `DISTINCT' comparison. We will probably change this in the future to never compare the hidden columns when executing `DISTINCT'. An example of this is: SELECT DISTINCT mp3id FROM band_downloads WHERE userid = 9 ORDER BY id DESC; and SELECT DISTINCT band_downloads.mp3id FROM band_downloads,band_mp3 WHERE band_downloads.userid = 9 AND band_mp3.id = band_downloads.mp3id ORDER BY band_downloads.id DESC; In the second case, using MySQL Server 3.23.x, you may get two identical rows in the result set (because the values in the hidden `id' column may differ). Note that this happens only for queries where that do not have the `ORDER BY' columns in the result. * If you execute a `PROCEDURE' on a query that returns an empty set, in some cases the `PROCEDURE' does not transform the columns. * Creation of a table of type `MERGE' doesn't check whether the underlying tables are compatible types. * If you use *Note `ALTER TABLE': alter-table. to add a `UNIQUE' index to a table used in a `MERGE' table and then add a normal index on the `MERGE' table, the key order is different for the tables if there was an old, non-`UNIQUE' key in the table. This is because *Note `ALTER TABLE': alter-table. puts `UNIQUE' indexes before normal indexes to be able to detect duplicate keys as early as possible.  File: manual.info, Node: news, Next: restrictions, Prev: error-handling, Up: Top Appendix D MySQL Change History ******************************* * Menu: * news-5-1-x:: Changes in Release 5.1.x (Production) * mem-news:: MySQL Enterprise Monitor Change History * connector-odbc-news:: MySQL Connector/ODBC (MyODBC) Change History * connector-net-news:: MySQL Connector/NET Change History * vstudio-plugin-news:: MySQL Visual Studio Plugin Change History * cj-news:: MySQL Connector/J Change History * news-connector-mxj:: MySQL Connector/MXJ Change History * ccpp-news:: MySQL Connector/C++ Change History * mysql-proxy-news:: MySQL Proxy Change History This appendix lists the changes from version to version in the MySQL source code through the latest version of MySQL 5.1, which is currently MySQL 5.1.59. We offer a version of the Manual for each series of MySQL releases (5.0, 5.1, and so forth). For information about changes in another release series of the MySQL database software, see the corresponding version of this Manual. We update this section as we add new features in the 5.1 series, so that everybody can follow the development process. Note that we tend to update the manual at the same time we make changes to MySQL. If you find a recent version of MySQL listed here that you can't find on our download page (`http://dev.mysql.com/downloads/'), it means that the version has not yet been released. The date mentioned with a release version is the date of the last Bazaar ChangeSet on which the release was based, not the date when the packages were made available. The binaries are usually made available a few days after the date of the tagged ChangeSet, because building and testing all packages takes some time. The manual included in the source and binary distributions may not be fully accurate when it comes to the release changelog entries, because the integration of the manual happens at build time. For the most up-to-date release changelog, please refer to the online version instead.  File: manual.info, Node: news-5-1-x, Next: mem-news, Prev: news, Up: news D.1 Changes in Release 5.1.x (Production) ========================================= * Menu: * news-5-1-59:: Changes in MySQL 5.1.59 (Not yet released) * news-5-1-58:: Changes in MySQL 5.1.58 (Not yet released) * news-5-1-57:: Changes in MySQL 5.1.57 (05 May 2011) * news-5-1-56:: Changes in MySQL 5.1.56 (01 March 2011) * news-5-1-55:: Changes in MySQL 5.1.55 (07 February 2011) * news-5-1-54:: Changes in MySQL 5.1.54 (26 November 2010) * news-5-1-53:: Changes in MySQL 5.1.53 (03 November 2010) * news-5-1-52sp1:: Release Notes for MySQL Enterprise 5.1.52sp1 [QSP] (21 February 2011) * news-5-1-52:: Changes in MySQL 5.1.52 (11 October 2010) * news-5-1-51:: Changes in MySQL 5.1.51 (10 September 2010) * news-5-1-50:: Changes in MySQL 5.1.50 (03 August 2010) * news-5-1-49sp1:: Release Notes for MySQL Enterprise 5.1.49sp1 [QSP] (28 September 2010) * news-5-1-49:: Changes in MySQL 5.1.49 (09 July 2010) * news-5-1-48:: Changes in MySQL 5.1.48 (02 June 2010) * news-5-1-47:: Changes in MySQL 5.1.47 (06 May 2010) * news-5-1-46sp1:: Release Notes for MySQL Enterprise 5.1.46sp1 [QSP] (23 June 2010) * news-5-1-46:: Changes in MySQL 5.1.46 (06 April 2010) * news-5-1-45:: Changes in MySQL 5.1.45 (01 March 2010) * news-5-1-44:: Changes in MySQL 5.1.44 (04 February 2010) * news-5-1-43sp1:: Release Notes for MySQL Enterprise 5.1.43sp1 [QSP] (25 March 2010) * news-5-1-43:: Changes in MySQL 5.1.43 (15 January 2010) * news-5-1-42:: Changes in MySQL 5.1.42 (15 December 2009) * news-5-1-41:: Changes in MySQL 5.1.41 (05 November 2009) * news-5-1-40sp1:: Release Notes for MySQL Enterprise 5.1.40sp1 [QSP] (25 November 2009) * news-5-1-40:: Changes in MySQL 5.1.40 (06 October 2009) * news-5-1-39:: Changes in MySQL 5.1.39 (04 September 2009) * news-5-1-38:: Changes in MySQL 5.1.38 (01 September 2009) * news-5-1-37sp1:: Release Notes for MySQL Enterprise 5.1.37sp1 [QSP] (10 October 2009) * news-5-1-37:: Changes in MySQL 5.1.37 (13 July 2009) * news-5-1-36:: Changes in MySQL 5.1.36 (16 June 2009) * news-5-1-35:: Changes in MySQL 5.1.35 (13 May 2009) * news-5-1-34sp1:: Release Notes for MySQL Enterprise 5.1.34sp1 [QSP] (25 June 2009) * news-5-1-34:: Changes in MySQL 5.1.34 (02 April 2009) * news-5-1-33:: Changes in MySQL 5.1.33 (13 March 2009) * news-5-1-32:: Changes in MySQL 5.1.32 (14 February 2009) * news-5-1-31sp1:: Release Notes for MySQL Enterprise 5.1.31sp1 [QSP] (19 March 2009) * news-5-1-31:: Changes in MySQL 5.1.31 (19 January 2009) * news-5-1-30:: Changes in MySQL 5.1.30 (14 November 2008 General Availability) * news-5-1-29:: Changes in MySQL 5.1.29 (11 October 2008) * news-5-1-28:: Changes in MySQL 5.1.28 (28 August 2008) * news-5-1-27:: Changes in MySQL 5.1.27 (Not released) * news-5-1-26:: Changes in MySQL 5.1.26 (30 June 2008) * news-5-1-25:: Changes in MySQL 5.1.25 (28 May 2008) * news-5-1-24:: Changes in MySQL 5.1.24 (08 April 2008) * news-5-1-23:: Changes in MySQL 5.1.23 (29 January 2008) * news-5-1-22:: Changes in MySQL 5.1.22 (24 September 2007 Release Candidate) * news-5-1-21:: Changes in MySQL 5.1.21 (16 August 2007) * news-5-1-20:: Changes in MySQL 5.1.20 (25 June 2007) * news-5-1-19:: Changes in MySQL 5.1.19 (25 May 2007) * news-5-1-18:: Changes in MySQL 5.1.18 (08 May 2007) * news-5-1-17:: Changes in MySQL 5.1.17 (04 April 2007) * news-5-1-16:: Changes in MySQL 5.1.16 (26 February 2007) * news-5-1-15:: Changes in MySQL 5.1.15 (25 January 2007) * news-5-1-14:: Changes in MySQL 5.1.14 (05 December 2006) * news-5-1-13:: Changes in MySQL 5.1.13 (Not released) * news-5-1-12:: Changes in MySQL 5.1.12 (24 October 2006) * news-5-1-11:: Changes in MySQL 5.1.11 (26 May 2006) * news-5-1-10:: Changes in MySQL 5.1.10 (Not released) * news-5-1-9:: Changes in MySQL 5.1.9 (12 April 2006) * news-5-1-8:: Changes in MySQL 5.1.8 (Not released) * news-5-1-7:: Changes in MySQL 5.1.7 (27 February 2006) * news-5-1-6:: Changes in MySQL 5.1.6 (01 February 2006) * news-5-1-5:: Changes in MySQL 5.1.5 (10 January 2006) * news-5-1-4:: Changes in MySQL 5.1.4 (21 December 2005) * news-5-1-3:: Changes in MySQL 5.1.3 (29 November 2005) * news-5-1-2:: Changes in MySQL 5.1.2 (Not released) * news-5-1-1:: Changes in MySQL 5.1.1 (Not released) An overview of features added in MySQL 5.1 can be found here: *Note mysql-nutshell::. For a full list of changes, please refer to the changelog sections for individual 5.1 releases. For discussion of upgrade issues that you may encounter for upgrades from MySQL 5.0 to MySQL 5.1, see *Note upgrading-from-previous-series::. For changes relating to MySQL Cluster NDB 6.x, see *Note mysql-cluster-news::.  File: manual.info, Node: news-5-1-59, Next: news-5-1-58, Prev: news-5-1-x, Up: news-5-1-x D.1.1 Changes in MySQL 5.1.59 (Not yet released) ------------------------------------------------ *Bugs fixed:* * *Partitioning*: Auto-increment columns of partitioned tables were checked even when they were not being written to. In debug builds, this could lead to a crash of the server. (Bug #11765667, Bug #58655) * *Note `ALTER TABLE {MODIFY|CHANGE} ... FIRST': alter-table. did nothing except rename columns if the old and new versions of the table had exactly the same structure with respect to column data types. As a result, the mapping of column name to column data was incorrect. The same thing happened for *Note `ALTER TABLE DROP COLUMN, ADD COLUMN': alter-table. statements intended to produce a new version of table with exactly the same structure as the old version. (Bug #61493, Bug #12652385) * For a database having a mixed-case name and a `lower_case_table_names' value of 1 or 2, calling a stored function using a fully qualified name including the database name failed. (Bug #60347, Bug #11840395) * For *Note `MyISAM': myisam-storage-engine. tables, attempts to insert incorrect data into an index `GEOMETRY' column could result in table corruption. (Bug #57323, Bug #11764487) * A race condition between loading a stored routine using the name qualified by the database name and dropping that database resulted in a spurious error message: `The table mysql.proc is missing, corrupt, or contains bad data' (Bug #47870, Bug #11756013)  File: manual.info, Node: news-5-1-58, Next: news-5-1-57, Prev: news-5-1-59, Up: news-5-1-x D.1.2 Changes in MySQL 5.1.58 (Not yet released) ------------------------------------------------ *Bugs fixed:* * *InnoDB Storage Engine*: If the server crashed while an XA transaction was prepared but not yet committed, the transaction could remain in the system after restart, and cause a subsequent shutdown to hang. (Bug #11766513, Bug #59641) * *Partitioning*: When executing a row-ordered retrieval index merge, the partitioning handler used memory from that allocated for the table, rather than that allocated to the query, causing table object memory not to be freed until the table was closed. (Bug #11766249, Bug #59316) * *Replication*: When *Note `mysqlbinlog': mysqlbinlog. was invoked using `--base64-output=decode-row' and `--start-position=POS', (where POS is a point in the binary log past the format description log event), a spurious error of the type shown here was generated: `malformed binlog: it does not contain any Format_description_log_event'... However, since there is nothing unsafe about not printing the format description log event, the error has been removed for this case. (Bug #12354268) * *Replication*: Typographical errors appeared in the text of several replication error messages. (The word `position' was misspelled as `postion'.) (Bug #11762616, Bug #55229) * After the fix for Bug#11889186, `MAKEDATE()' arguments with a year part greater than 9999 raised an assertion. (Bug #12403504) * An assertion could be raised due to a missing `NULL' value check in `Item_func_round::fix_length_and_dec()'. (Bug #12392636) * In debug builds on Solaris, an assertion was raised if a reverse IP lookup with `gethostbyaddr_r()' failed. (Bug #12377872) * MySQL did not build if configured with both `--with-debug' and `--with-libedit'. (Bug #12329909) * A problem introduced in 5.1.57 caused very old (MySQL 4.0) clients to be unable to connect to the server. (Bug #61222, Bug #12563279) * Using *Note `CREATE EVENT IF NOT EXISTS': create-event. for an event that already existed and was enabled caused multiple instances of the event to run. (Bug #61005, Bug #12546938) * The incorrect `max_length' value for *Note `YEAR': year. values could be used in temporary result tables for *Note `UNION': union, leading to incorrect results. (Bug #59343, Bug #11766270) * In `Item_func_in::fix_length_and_dec()', a Valgrind warning for uninitialized values was corrected. (Bug #59270, Bug #11766212) * In `ROUND()' calculations, a Valgrind warning for uninitialized memory was corrected. (Bug #58937, Bug #11765923) * Valgrind warnings caused by comparing index values to an uninitialized field were corrected. (Bug #58705, Bug #11765713) * *Note `LOAD DATA INFILE': load-data. errors could leak I/O cache memory. (Bug #58072, Bug #11765141) * For *Note `LOAD DATA INFILE': load-data, multibyte character sequences could be pushed onto a stack too small to accommodate them. (Bug #58069, Bug #11765139) * An embedded client would abort rather than issue an error message if it issued a TEE command (`\T FILE_NAME') and the directory containing the file did not exist. This occurred because the wrong error handler was called. (Bug #57491, Bug #11764633) * In debug builds, `Field_new_decimal::store_value()' was subject to buffer overflows. (Bug #55436, Bug #11762799) * On Linux, the *Note `mysql': mysql. client built using the bundled `libedit' did not read `~/.editrc'. (Bug #49967, Bug #11757855) * The optimizer sometimes incorrectly processed `HAVING' clauses for queries that did not also have an `ORDER BY' clause. (Bug #48916, Bug #11756928) * `PROCEDURE ANALYZE()' could leak memory for `NULL' results, and could return incorrect results if used with a `LIMIT' clause. (Bug #48137, Bug #11756242) * On some platforms, the `Incorrect value: xxx for column yyy at row zzz' error produced by *Note `LOAD DATA INFILE': load-data. could have an incorrect value of ZZZ. (Bug #46895, Bug #11755168) * In MySQL 5.1 and up, if a table had triggers that used syntax supported in 5.0 but not 5.1, the table became unavailable. Now the table is marked as having broken triggers. (Bug #45235, Bug #11753738) * An attempt to install nonexistent files during installation was corrected. (Bug #43247, Bug #11752142) * On FreeBSD 64-built builds of the embedded server, exceptions were not prevented from propagating into the embedded application. (Bug #38965, Bug #11749418)  File: manual.info, Node: news-5-1-57, Next: news-5-1-56, Prev: news-5-1-58, Up: news-5-1-x D.1.3 Changes in MySQL 5.1.57 (05 May 2011) ------------------------------------------- *Functionality added or changed:* * When invoked with the `--auto-generate-sql' option, *Note `mysqlslap': mysqlslap. dropped the schema specified with the `--create-schema' option at the end of the test run, which may have been unexpected by the user. *Note `mysqlslap': mysqlslap. no longer drops the schema, but has a new `--create-and-drop-schema' option that both creates and drops a schema. (Bug #58090, Bug #11765157) * A new system variable, `max_long_data_size', now controls the maximum size of parameter values that can be sent with the `mysql_stmt_send_long_data()' C API function. If not set at server startup, the default is the value of the `max_allowed_packet' system variable. This variable is deprecated. In MySQL 5.6, it is removed and the maximum parameter size is controlled by `max_allowed_packet'. *Bugs fixed:* * *InnoDB Storage Engine*: *Replication*: Trying to update a column, previously set to `NULL', of an *Note `InnoDB': innodb-storage-engine. table with no primary key caused replication to fail with `Can't find record in 'TABLE' on the slave'. (Bug #11766865, Bug #60091) * *InnoDB Storage Engine*: The server could halt if `InnoDB' interpreted a very heavy I/O load for 15 minutes or more as an indication that the server was hung. This change fixes the logic that measures how long `InnoDB' threads were waiting, which formerly could produce false positives. (Bug #11877216, Bug #11755413, Bug #47183) * *Replication*: Using the `--server-id' option with *Note `mysqlbinlog': mysqlbinlog. could cause format description log events to be filtered out of the binary log, leaving *Note `mysqlbinlog': mysqlbinlog. unable to read the remainder of the log. Now such events are always read without regard to the value of this option. As part of the the fix for this problem, *Note `mysqlbinlog': mysqlbinlog. now also reads rotate log events without regard to the value of `--server-id'. (Bug #11766427, Bug #59530) * *Partitioning*: A problem with a previous fix for poor performance of *Note `INSERT ON DUPLICATE KEY UPDATE': insert. statements on tables having many partitions caused the handler function for reading a row from a specific index to fail to store the ID of the partition last used. This caused some statements to fail with `Can't find record' errors. (Bug #59297, Bug #11766232) * *Note `InnoDB': innodb-storage-engine. invoked some `zlib' functions without proper initialization. (Bug #11849231) * Two unused test files in `storage/ndb/test/sql' contained incorrect versions of the GNU Lesser General Public License. The files and the directory containing them have been removed. (Bug #11810224) See also Bug #11810156. * Selecting from a view for which the definition included a `HAVING' clause failed with an error: 1356: View '...' references invalid table(s) or column(s) or function(s) or definer/invoker of view lack rights to use them (Bug #60295, Bug #11829681) * The server permitted `max_allowed_packet' to be set lower than `net_buffer_length', which does not make sense because `max_allowed_packet' is the upper limit on `net_buffer_length' values. Now a warning occurs and the value remains unchanged. (Bug #59959, Bug #11766769) * The server read one byte too many when trying to process an XML string lacking a closing quote (`'') or double quote (`"') character used as an argument for `UpdateXML()' or `ExtractValue()'. (Bug #59901, Bug #11766725) See also Bug #44332, Bug #11752979. * Attempting to create a spatial index on a *Note `CHAR': char. column longer than 31 bytes led to an assertion failure if the server was compiled with safemutex support. (Bug #59888, Bug #11766714) * Aggregation followed by a subquery could produce an incorrect result. (Bug #59839, Bug #11766675) * An incorrect character set pointer passed to `my_strtoll10_mb2()' caused an assertion to be raised. (Bug #59648, Bug #11766519) * A missing variable initialization for `Item_func_set_user_var' objects could cause an assertion to be raised. (Bug #59527, Bug #11766424) * *Note `mysqldump': mysqldump. did not quote database names in *Note `ALTER DATABASE': alter-database. statements in its output, which could cause an error at reload time for database names containing a dash. (Bug #59398, Bug #11766310) * In `Item_func_month::val_str()', a Valgrind warning for a too-late `NULL' value check was corrected. (Bug #59166, Bug #11766126) * In `Item::get_date', a Valgrind warning for a missing `NULL' value check was corrected. (Bug #59164, Bug #11766124) * In `extract_date_time()', a Valgrind warning for a missing end-of-string check was corrected. (Bug #59151, Bug #11766112) * In string context, the `MIN()' and `MAX()' functions did not take into account the unsignedness of a `BIGINT UNSIGNED' argument. (Bug #59132, Bug #11766094) * In `Item_func::val_decimal', a Valgrind warning for a missing `NULL' value check was corrected. (Bug #59125, Bug #11766087) * In `Item_func_str_to_date::val_str', a Valgrind warning for an uninitialized variable was corrected. (Bug #58154, Bug #11765216) * The code for `PROCEDURE ANALYSE()' had a missing `DBUG_RETURN' statement, which could cause a server crash in debug builds. (Bug #58140, Bug #11765202) * An assertion could be raised in `Item_func_int_val::fix_num_length_and_dec()' due to overflow for geometry functions. (Bug #57900, Bug #11764994) * An assertion could be raised if a statement that required a name lock on a table (for example, *Note `DROP TRIGGER': drop-trigger.) executed concurrently with an `INFORMATION_SCHEMA' query that also used the table. (Bug #56541, Bug #11763784) * For a client connected using SSL, the `Ssl_cipher_list' status variable was empty and did not show the possible cipher types. (Bug #52596, Bug #11760210) * With `lower_case_table_names=2', resolution of objects qualified by database names could fail. (Bug #50924, Bug #11758687) * A potential invalid memory access discovered by Valgrind was fixed. (Bug #48053, Bug #11756169) * Bitmap functions used in one thread could change bitmaps used by other threads, causing an assertion to be raised. (Bug #43152, Bug #11752069) * *Note `SHOW EVENTS': show-events. did not always show events from the correct database. (Bug #41907, Bug #11751148)  File: manual.info, Node: news-5-1-56, Next: news-5-1-55, Prev: news-5-1-57, Up: news-5-1-x D.1.4 Changes in MySQL 5.1.56 (01 March 2011) --------------------------------------------- *Functionality added or changed:* * *Note `mysqldump --xml': mysqldump. now displays comments from column definitions. (Bug #13618, Bug #11745324) *Bugs fixed:* * *InnoDB Storage Engine*: *Note `InnoDB': innodb-storage-engine. returned values for `rows examined' in the query plan that were higher than expected. `NULL' values were treated in an inconsistent way. The inaccurate statistics could trigger `false positives' in combination with the `MAX_JOIN_SIZE' setting, because the queries did not really examine as many rows as reported. (Bug #30423) * *Partitioning*: Trying to use the same column more than once in the partitioning key when partitioning a table by `KEY' caused *Note `mysqld': mysqld. to crash. Such duplication of key columns is now expressly disallowed, and fails with an appropriate error. (Bug #53354, Bug #57924) * *Replication*: When using the statement-based logging format, *Note `INSERT ON DUPLICATE KEY UPDATE': insert-on-duplicate. and *Note `INSERT IGNORE': insert. statements affecting transactional tables that did not fail were not written to the binary log if they did not insert any rows. (With statement-based logging, all successful statements should be logged, whether they do or do not cause any rows to be changed.) (Bug #59338, Bug #11766266) * *Replication*: Formerly, *Note `STOP SLAVE': stop-slave. stopped the slave I/O thread first and then stopped the slave SQL thread; thus, it was possible for the I/O thread to stop after replicating only part of a transaction which the SQL thread was executing, in which case--if the transaction could not be rolled back safely--the SQL thread could hang. Now, *Note `STOP SLAVE': stop-slave. stops the slave SQL thread first and then stops the I/O thread; this guarantees that the I/O thread can fetch any remaining events in the transaction that the SQL thread is executing, so that the SQL thread can finish the transaction if it cannot be rolled back safely. (Bug #58546, Bug #11765563) * A query of the following form returned an incorrect result, where the values for COL_NAME in the result set were entirely replaced with `NULL' values: SELECT DISTINCT COL_NAME ... ORDER BY COL_NAME DESC; (Bug #59308, Bug #11766241) * *Note `DELETE': delete. or *Note `UPDATE': update. statements could fail if they used *Note `DATE': datetime. or *Note `DATETIME': datetime. values with a year, month, or day part of zero. (Bug #59173) * The `ESCAPE' clause for the `LIKE' operator allows only expressions that evaluate to a constant at execution time, but aggregate functions were not being rejected. (Bug #59149, Bug #11766110) * Memory leaks detected by Valgrind, some of which could cause incorrect query results, were corrected. (Bug #59110, Bug #11766075) * *Note `mysqlslap': mysqlslap. failed to check for a `NULL' return from *Note `mysql_store_result()': mysql-store-result. and crashed trying to process the result set. (Bug #59109, Bug #11766074) * In debug builds, `SUBSTRING_INDEX(FORMAT(...), FORMAT(...))' could cause a server crash. (Bug #58371, Bug #11765406) * When *Note `mysqladmin': mysqladmin. was run with the `--sleep' and `--count' options, it went into an infinite loop executing the specified command. (Bug #58221, Bug #11765270) * Some string manipulating SQL functions use a shared string object intended to contain an immutable empty string. This object was used by the SQL function `SUBSTRING_INDEX()' to return an empty string when one argument was of the wrong datatype. If the string object was then modified by the SQL function `INSERT()', undefined behavior ensued. (Bug #58165, Bug #11765225) * Parsing nested regular expressions could lead to recursion resulting in a stack overflow crash. (Bug #58026, Bug #11765099) * The *Note `mysql': mysql. client went into an infinite loop if the standard input was a directory. (Bug #57450, Bug #11764598) * The expression `CONST1 BETWEEN CONST2 AND FIELD' was optimized incorrectly and produced incorrect results. (Bug #57030, Bug #11764215) * Some RPM installation scripts used a hardcoded value for the data directory, which could result in a failed installation for users who have a nonstandard data directory location. The same was true for other configuration values such as the PID file name. (Bug #56581, Bug #11763817) * On FreeBSD and OpenBSD, the server incorrectly checked the range of the system date, causing legal values to be rejected. (Bug #55755, Bug #11763089) * When using `ExtractValue()' or `UpdateXML()', if the XML to be read contained an incomplete XML comment, MySQL read beyond the end of the XML string when processing, leading to a crash of the server. (Bug #44332, Bug #11752979)  File: manual.info, Node: news-5-1-55, Next: news-5-1-54, Prev: news-5-1-56, Up: news-5-1-x D.1.5 Changes in MySQL 5.1.55 (07 February 2011) ------------------------------------------------ *Functionality added or changed:* * The time zone tables available at `http://dev.mysql.com/downloads/timezones.html' have been updated. These tables can be used on systems such as Windows or HP-UX that do not include zoneinfo files. (Bug #40230) *Bugs fixed:* * *Performance*: Queries involving *Note `InnoDB': innodb-storage-engine. tables in the `INFORMATON_SCHEMA' tables *Note `TABLE_CONSTRAINTS': table-constraints-table, *Note `KEY_COLUMN_USAGE': key-column-usage-table, or *Note `REFERENTIAL_CONSTRAINTS': referential-constraints-table. were slower than necessary because statistics were rechecked more often than required, even more so when many foreign keys were present. The improvement to this may be of particular benefit to users of MySQL Enterprise Monitor with many monitored servers or tens of thousands of tables. (Bug #43818, Bug #11752585) * *Incompatible Change*: When `auto_increment_increment' is greater than one, values generated by a bulk insert that reaches the maximum column value could wrap around rather producing an overflow error. As a consequence of the fix, it is no longer possible for an auto-generated value to be equal to the maximum `BIGINT UNSIGNED' value. It is still possible to store that value manually, if the column can accept it. (Bug #39828, Bug #11749800) * *Important Change*: *Partitioning*: Date and time functions used as partitioning functions now have the types of their operands checked; use of a value of the wrong type is now disallowed in such cases. In addition, `EXTRACT(WEEK FROM col)', where COL is a *Note `DATE': datetime. or *Note `DATETIME': datetime. column, is now disallowed altogether because its return value depends on the value of the `default_week_format' system variable. (Bug #54483, Bug #11761948) See also Bug #57071, Bug #11764255. * *InnoDB Storage Engine*: A compilation problem affected the `InnoDB' source code on NetBSD/sparc64. (Bug #59327) See also Bug #53916. * *InnoDB Storage Engine*: In *Note `InnoDB': innodb-storage-engine. status output, the value for `I/O sum[]' could be incorrect, displayed as a very large number. (Bug #57600) * *InnoDB Storage Engine*: The server could crash with an assertion error, if a stored procedure, stored function, or trigger modified one *Note `InnoDB': innodb-storage-engine. table containing an auto-increment (http://dev.mysql.com/doc/innodb-plugin/1.0/en/glossary.html#glos_auto_increment) column, and dropped another *Note `InnoDB': innodb-storage-engine. table containing an auto-increment column. (Bug #56228) * *InnoDB Storage Engine*: It was not possible to query the `information_schema.innodb_trx' table while other connections were running queries involving BLOB types. (Bug #55397, Bug #11762763) * *InnoDB Storage Engine*: The *Note `OPTIMIZE TABLE': optimize-table. statement would reset the auto-increment counter for an *Note `InnoDB': innodb-storage-engine. table. Now the auto-increment value is preserved across this operation. (Bug #18274) * *Partitioning*: Failed *Note `ALTER TABLE ... PARTITION': alter-table. statements could cause memory leaks. (Bug #56380, Bug #11763641) See also Bug #46949, Bug #11755209, Bug #56996, Bug #11764187. * *Replication*: When closing a session that used temporary tables, binary logging could sometimes fail with a spurious `Failed to write the DROP statement for temporary tables to binary log'. (Bug #57288) * *Replication*: By default, a value is generated for an `AUTO_INCREMENT' column by inserting either `NULL' or 0 into the column. Setting the `NO_AUTO_VALUE_ON_ZERO' server SQL mode suppresses this behavior for 0, so that it occurs only when `NULL' is inserted into the column. This behavior is also followed on a replication slave (by the slave SQL thread) when applying events that have been logged on the master using the statement-based format. However, when applying events that had been logged using the row-based format, `NO_AUTO_VALUE_ON_ZERO' was ignored, which could lead to an assertion. To fix this issue, the value of an `AUTO_INCREMENT' column is no longer generated when applying an event that was logged using the row-based row format, as this value is already contained in the changes applied on the slave. (Bug #56662) * *Replication*: The *Note `BINLOG': binlog. statement modified the values of session variables, which could lead to problems with operations such a point-in-time recovery. One such case occurred when replaying a row-based binary log which relied on setting `foreign_key_checks = OFF' on the session level in order to create and populate a set of *Note `InnoDB': innodb-storage-engine. tables having foreign key constraints. (Bug #54903) * *Replication*: *Note `mysqlbinlog': mysqlbinlog. printed *Note `USE': use. statements to its output only when the default database changed between events. To illustrate how this could cause problems, suppose that a user issued the following sequence of statements: CREATE DATABASE mydb; USE mydb; CREATE TABLE mytable (COLUMN_DEFINITIONS); DROP DATABASE mydb; CREATE DATABASE mydb; USE mydb; CREATE TABLE mytable (COLUMN_DEFINITIONS); When played back using *Note `mysqlbinlog': mysqlbinlog, the second *Note `CREATE TABLE': create-table. statement failed with `Error: No Database Selected' because the second *Note `USE': use. statement was not played back, due to the fact that a database other than `mydb' was never selected. This fix insures that *Note `mysqlbinlog': mysqlbinlog. outputs a *Note `USE': use. statement whenever it reads one from the binary log. (Bug #50914, Bug #11758677) * *Replication*: Previously, when a statement failed with a different error on the slave than on the master, the slave SQL thread displayed a message containing: * The error message for the master error code * The master error code * The error message for the slaves error code * The slave error code However, the slave has no information with which to fill in any print format specifiers for the master message, so it actually displayed the message format string. To make it clearer that the slave is not displaying the actual message as it appears on the master, the slave now indicates that the master part of the output is the message format, not the actual message. For example, previously the slave displayed information like this: Error: "Query caused different errors on master and slave. Error on master: 'Duplicate entry '%-.192s' for key %d' (1062), Error on slave: 'no error' (0). Default database: 'test'. Query: 'insert into t1 values(1),(2)'" (expected different error codes on master and slave) Now the slave displays this: Error: "Query caused different errors on master and slave. Error on master: message format='Duplicate entry '%-.192s' for key %d' error code=1062 ; Error on slave: actual message='no error', error code=0. Default database: 'test'. Query: 'insert into t1 values(1),(2)'" (expected different error codes on master and slave) (Bug #46697) * *Replication*: When an error occurred in the generation of the name for a new binary log file, the error was logged but not shown to the user. (Bug #46166) See also Bug #37148, Bug #11748696, Bug #40611, Bug #11750196, Bug #43929, Bug #51019. * `MIN(YEAR_COL)' could return an incorrect result in some cases. (Bug #59211, Bug #11766165) * If `max_allowed_packet' was set larger than 16MB, the server failed to reject too-large packets with `Packet too large' errors. (Bug #58887, Bug #11765878) * Issuing *Note `EXPLAIN EXTENDED': explain. for a query that would use condition pushdown could cause *Note `mysqld': mysqld. to crash. (Bug #58553, Bug #11765570) * *Note `EXPLAIN': explain. could crash for queries that used `GROUP_CONCAT()'. (Bug #58396) * Configuration with maintainer mode enabled resulted in errors when compiling with `icc'. (Bug #57991, Bug #58871) * Unnecessary subquery evaluation in contexts such as statement preparation or view creation could cause a server crash. (Bug #57703) * View creation could produce Valgrind warnings. (Bug #57352) * `NULL' geometry values could cause a crash in `Item_func_spatial_collection::fix_length_and_dec'. (Bug #57321) * The `cp1251' character set did not properly support the Euro sign (`0x88'). For example, converting a string containing this character to `utf8' resulted in `'?'' rather than the `utf8' Euro sign. (Bug #56639) * Some unsigned system variables could be displayed with negative values. (Bug #55794) * *Note `CREATE DATABASE': create-database. and *Note `DROP DATABASE': drop-database. caused *Note `mysql --one-database': mysql. to lose track of the statement-filtering context. (Bug #54899) * An assertion could be raised during concurrent execution of *Note `DROP DATABASE': drop-database. and *Note `REPAIR TABLE': repair-table. if the drop deleted a table's `.TMD' file at the same time the repair tried to read details from the old file that was just removed. A problem could also occur when *Note `DROP TABLE': drop-table. tried to remove all files belonging to a table at the same time *Note `REPAIR TABLE': repair-table. had just deleted the table's `.TMD' file. (Bug #54486) * When *Note `mysqld': mysqld. printed crash dump information, it incorrectly indicated that some valid pointers were invalid. (Bug #51817) * On FreeBSD, if *Note `mysqld': mysqld. was killed with a `SIGHUP' signal, it could corrupt *Note `InnoDB': innodb-storage-engine. `.ibd' files. (Bug #51023, Bug #11758773) * An assertion could be raised if -1 was inserted into an `AUTO_INCREMENT' column by a statement writing more than one row. (Bug #50619, Bug #11758417) * If a client supplied a user name longer than the maximum 16 characters allowed for names stored in the MySQL grant tables, all characters were being considered significant. Historically, only the first 16 characters were used to check for a match; this behavior was restored. (Bug #49752) * The `my_seek()' and `my_tell()' functions ignored the `MY_WME' flag when they returned an error, which could cause client programs to hang. (Bug #48451) * During assignment of values to system variables, legality checks on the value range occurred too late, preventing proper error checking. (Bug #43233) * On Solaris, time-related functions such as `NOW()' or `SYSDATE()' could return a constant value. (Bug #42054) * If the remote server for a *Note `FEDERATED': federated-storage-engine. table could not be accessed, queries for the *Note `INFORMATION_SCHEMA.TABLES': tables-table. table failed. (Bug #35333)  File: manual.info, Node: news-5-1-54, Next: news-5-1-53, Prev: news-5-1-55, Up: news-5-1-x D.1.6 Changes in MySQL 5.1.54 (26 November 2010) ------------------------------------------------ *Functionality added or changed:* * Support for the `IBMDB2I' storage engine has been removed. (Bug #58079) * The `pstack' library was nonfunctional and has been removed, along with the `--with-pstack' option for `configure'. The `--enable-pstack' option for *Note `mysqld': mysqld. is deprecated and will be removed in MySQL 5.5. (Bug #57210) *Bugs fixed:* * *Performance*: *InnoDB Storage Engine*: Improved concurrency when several *Note `ANALYZE TABLE': analyze-table. or *Note `SHOW TABLE STATUS': show-table-status. statements are run simultaneously for `InnoDB' tables. (Bug #53046) * *InnoDB Storage Engine*: Dropping an `InnoDB' index used by a foreign key constraint, while `foreign_key_checks' was set to 0, could cause the server to crash with an assertion. This operation now does not cause a crash. The foreign key constraint can no longer be enforced once the associated index is removed, so do not rely on it for referential integrity in this case. (Bug #11762483, Bug #55084) * *InnoDB Storage Engine*: For an `InnoDB' table created with `ROW_FORMAT=COMPRESSED' or `ROW_FORMAT=DYNAMIC', a query using the `READ UNCOMMITTED' isolation level could cause the server to stop with an assertion error, if `BLOB' or other large columns that use off-page storage were being inserted at the same time. (Bug #57799) * *InnoDB Storage Engine*: An existing `InnoDB' table could be switched to `ROW_FORMAT=COMPRESSED' implicitly by a `KEY_BLOCK_SIZE' clause in an *Note `ALTER TABLE': alter-table. statement. Now, the row format is only switched to compressed if there is an explicit `ROW_FORMAT=COMPRESSED' clause. on the *Note `ALTER TABLE': alter-table. statement. Any valid, nondefault `ROW_FORMAT' parameter takes precedence over `KEY_BLOCK_SIZE' when both are specified. `KEY_BLOCK_SIZE' only enables `ROW_FORMAT=COMPRESSED' if `ROW_FORMAT' is not specified on either the `CREATE TABLE' or `ALTER TABLE' statement, or is specified as `DEFAULT'. In case of a conflict between `KEY_BLOCK_SIZE' and `ROW_FORMAT' clauses, the `KEY_BLOCK_SIZE' is ignored if `innodb_strict_mode' is off, and the statement causes an error if `innodb_strict_mode' is on. (Bug #56632) * *InnoDB Storage Engine*: The clause `KEY_BLOCK_SIZE=0' is now allowed on *Note `CREATE TABLE': create-table. and *Note `ALTER TABLE': alter-table. statements for `InnoDB' tables, regardless of the setting of `innodb_strict_mode'. The zero value has the effect of resetting the `KEY_BLOCK_SIZE' table parameter to its default value, depending on the `ROW_FORMAT' parameter, as if it had not been specified. That default is 8 if ROW_FORMAT=COMPRESSED. Otherwise, KEY_BLOCK_SIZE is not used or stored with the table parameters. As a consequence of this fix, `ROW_FORMAT=FIXED' is not allowed when the `innodb_strict_mode' is enabled. (Bug #56628) * *InnoDB Storage Engine*: `InnoDB' startup messages now include the start and end times for buffer pool initialization, and the total buffer pool size. (Bug #48026) * *Partitioning*: An *Note `INSERT ... ON DUPLICATE KEY UPDATE COLUMN = 0': insert. statement on an `AUTO_INCREMENT' column caused the debug server to crash. (Bug #57890) * *Partitioning*: An *Note `ALTER TABLE': alter-table-partition-operations. statement acting on table partitions that failed while the affected table was locked could cause the server to crash. (Bug #56172) * Several compilation problems were fixed. (Bug #57992, Bug #57993, Bug #57994, Bug #57995, Bug #57996, Bug #57997, Bug #58057) * Passing a string that was not null-terminated to `UpdateXML()' or `ExtractValue()' caused the server to fail with an assertion. (Bug #57279, Bug #11764447) * Queries executed using the Index Merge access method and a temporary file could return incorrect results. (Bug #56862) * Valgrind warnings about overlapping memory when double-assigning the same variable were corrected. (Bug #56138) * An error in a stored procedure could leave the session in a different default database. (Bug #54375) * Grouping by a `TIME_TO_SEC()' function result could cause a server crash or incorrect results. Grouping by a function returning a *Note `BLOB': blob. could cause an unexpected `Duplicate entry' error and incorrect result. (Bug #52160) * The `find_files()' function used by *Note `SHOW': show. statements performed redundant and unnecessary memory allocation. (Bug #51208) * The Windows sample option files contained values more appropriate for Linux. (Bug #50021) * A failed *Note `RENAME TABLE': rename-table. operation could prevent a *Note `FLUSH TABLES WITH READ LOCK': flush. from completing. (Bug #47924)  File: manual.info, Node: news-5-1-53, Next: news-5-1-52sp1, Prev: news-5-1-54, Up: news-5-1-x D.1.7 Changes in MySQL 5.1.53 (03 November 2010) ------------------------------------------------ *Bugs fixed:* * *InnoDB Storage Engine*: *Security Fix*: A failed *Note `CREATE TABLE': create-table. statement for an *Note `InnoDB': innodb-storage-engine. table could allocate memory that was never freed. (Bug #56947) * *InnoDB Storage Engine*: A followup fix to bug #54678. *Note `TRUNCATE TABLE': truncate-table. could still cause a crash (assertion error) in the debug version of the server. (Bug #57700) * *InnoDB Storage Engine*: The `InnoDB' system tablespace could grow continually for a server under heavy load. (Bug #57611) * *InnoDB Storage Engine*: Turning off the `innodb_stats_on_metadata' option could prevent the *Note `ANALYZE TABLE': analyze-table. statement from updating the cardinality statistics of *Note `InnoDB': innodb-storage-engine. tables. (Bug #57252) * *InnoDB Storage Engine*: If the server crashed during an *Note `ALTER TABLE': alter-table. operation on an `InnoDB' table, examining the table through `SHOW CREATE TABLE' or querying the `INFORMATION_SCHEMA' tables could cause the server to stop with an assertion error. (Bug #56982) * *InnoDB Storage Engine*: A query for an *Note `InnoDB': innodb-storage-engine. table could return the wrong value if a column value was changed to a different case, and the column had a case-insensitive index. (Bug #56680) * *InnoDB Storage Engine*: A large number of foreign key declarations could cause the output of the `SHOW CREATE STATEMENT' statement to be truncated. (Bug #56143) * *InnoDB Storage Engine*: A compilation problem affected the `InnoDB' source code on NetBSD/sparc64. (Bug #53916) See also Bug #59327. * *Replication*: *Note `SET PASSWORD': set-password. caused row-based replication to fail between a MySQL 5.1 master and a MySQL 5.5 slave. This fix makes it possible to replicate *Note `SET PASSWORD': set-password. correctly, using row-based replication between a master running MySQL 5.1.53 or a later MySQL 5.1 release to a slave running MySQL 5.5.7 or a later MySQL 5.5 release. (Bug #57098) See also Bug #55452, Bug #57357. * *Replication*: An *Note `ALTER TABLE': alter-table. statement that altered a column of a *Note `MyISAM': myisam-storage-engine. table without setting the column's size caused the binary log to become corrupted when the table map was unexpectedly set to 0 by updates (including deletes) on multiple tables, leading to replication failure when more than one table received the same table map ID. (Bug #56226, Bug #11763509) * *Replication*: When *Note `STOP SLAVE': stop-slave. is issued, the slave SQL thread rolls back the current transaction and stops immediately if the transaction updates only tables which use transactional storage engines are updated. Previously, this occurred even when the transaction contained *Note `CREATE TEMPORARY TABLE': create-table. statements, *Note `DROP TEMPORARY TABLE': drop-table. statements, or both, although these statements cannot be rolled back. Because temporary tables persist for the lifetime of a user session (in the case, the replication user), they remain until the slave is stopped or reset. When the transaction is restarted following a subsequent *Note `START SLAVE': start-slave. statement, the SQL thread aborts with an error that a temporary table to be created (or dropped) already exists (or does not exist, in the latter case). Following this fix, if an ongoing transaction contains *Note `CREATE TEMPORARY TABLE': create-table. statements, *Note `DROP TEMPORARY TABLE': drop-table. statements, or both, the SQL thread now waits until the transaction ends, then stops. (Bug #56118, Bug #11763416) * *Replication*: If there exist both a temporary table and a non-temporary table having the same name, updates normally apply only to the temporary table, with the exception of a *Note `CREATE TABLE ... SELECT': create-table-select. statement that creates a non-temporary table having the same name as an existing temporary table. When such a statement was replicated using the `MIXED' logging format, and the statement was unsafe for row-based logging, updates were misapplied to the temporary table. (Bug #55478) See also Bug #47899, Bug #55709. * *Replication*: When a slave tried to execute a transaction larger than the slave's value for `max_binlog_cache_size', it crashed. This was caused by an assertion that the server should roll back only the statement but not the entire transaction when the error `ER_TRANS_CACHE_FULL' occurred. However, the slave SQL thread always rolled back the entire transaction whenever any error occurred, regardless of the type of error. (Bug #55375) * *Replication*: When making changes to relay log settings using *Note `CHANGE MASTER TO': change-master-to, the I/O cache was not cleared. This could result in replication failure when the slave attempted to read stale data from the cache and then stopped with an assertion. (Bug #55263) * *Replication*: Trying to read from a binary log containing a log event of an invalid type caused the slave to crash. (Bug #38718) * *Replication*: When replicating the `mysql.tables_priv' table, the `Grantor' column was not replicated, and was thus left empty on the slave. (Bug #27606) * *Note `SET GLOBAL debug': set-option. could cause a crash on Solaris if the server failed to open the trace file. (Bug #57274) * A *Note `SELECT': select. statement could produce a different number of rows than a *Note `CREATE TABLE ... SELECT': create-table-select. that was supposed to select the same rows. (Bug #56423) * On file systems with case insensitive file names, and `lower_case_table_names=2', the server could crash due to a table definition cache inconsistency. (Bug #46941) * Handling of host name lettercase in *Note `GRANT': grant. statements was inconsistent. (Bug #36742)  File: manual.info, Node: news-5-1-52sp1, Next: news-5-1-52, Prev: news-5-1-53, Up: news-5-1-x D.1.8 Release Notes for MySQL Enterprise 5.1.52sp1 [QSP] (21 February 2011) --------------------------------------------------------------------------- This is a _Service Pack_ release of the MySQL Enterprise Server 5.1. *Functionality added or changed:* * Support for the `IBMDB2I' storage engine has been removed. (Bug #58079) *Bugs fixed:* * *Incompatible Change*: When `auto_increment_increment' is greater than one, values generated by a bulk insert that reaches the maximum column value could wrap around rather producing an overflow error. As a consequence of the fix, it is no longer possible for an auto-generated value to be equal to the maximum `BIGINT UNSIGNED' value. It is still possible to store that value manually, if the column can accept it. (Bug #39828, Bug #11749800) * *Important Change*: *Partitioning*: Date and time functions used as partitioning functions now have the types of their operands checked; use of a value of the wrong type is now disallowed in such cases. In addition, `EXTRACT(WEEK FROM col)', where COL is a *Note `DATE': datetime. or *Note `DATETIME': datetime. column, is now disallowed altogether because its return value depends on the value of the `default_week_format' system variable. (Bug #54483, Bug #11761948) See also Bug #57071, Bug #11764255. * *InnoDB Storage Engine*: The `InnoDB' system tablespace could grow continually for a server under heavy load. (Bug #57611) * *InnoDB Storage Engine*: If the server crashed during an *Note `ALTER TABLE': alter-table. operation on an `InnoDB' table, examining the table through `SHOW CREATE TABLE' or querying the `INFORMATION_SCHEMA' tables could cause the server to stop with an assertion error. (Bug #56982) * *Partitioning*: Failed *Note `ALTER TABLE ... PARTITION': alter-table. statements could cause memory leaks. (Bug #56380, Bug #11763641) See also Bug #46949, Bug #11755209, Bug #56996, Bug #11764187. * `MIN(YEAR_COL)' could return an incorrect result in some cases. (Bug #59211, Bug #11766165) * *Note `EXPLAIN': explain. could crash for queries that used `GROUP_CONCAT()'. (Bug #58396) * Unnecessary subquery evaluation in contexts such as statement preparation or view creation could cause a server crash. (Bug #57703) * View creation could produce Valgrind warnings. (Bug #57352) * `NULL' geometry values could cause a crash in `Item_func_spatial_collection::fix_length_and_dec'. (Bug #57321) * *Note `SET GLOBAL debug': set-option. could cause a crash on Solaris if the server failed to open the trace file. (Bug #57274) * Valgrind warnings about overlapping memory when double-assigning the same variable were corrected. (Bug #56138) * On FreeBSD, if *Note `mysqld': mysqld. was killed with a `SIGHUP' signal, it could corrupt *Note `InnoDB': innodb-storage-engine. `.ibd' files. (Bug #51023, Bug #11758773)  File: manual.info, Node: news-5-1-52, Next: news-5-1-51, Prev: news-5-1-52sp1, Up: news-5-1-x D.1.9 Changes in MySQL 5.1.52 (11 October 2010) ----------------------------------------------- *Bugs fixed:* * *InnoDB Storage Engine*: *Security Fix*: Issuing *Note `TRUNCATE TABLE': truncate-table. and examining the same table's information in the `INFORMATION_SCHEMA' database at the same time could cause a crash in the debug version of the server. (Bug #54678) * *Security Fix*: The server crashed for assignment of values of types other than `Geometry' to items of type `GeometryCollection' (`MultiPoint', `MultiCurve', `MultiSurface'). Now the server checks the field type and fails with `bad geometry value' if it detects incorrect parameters. (Bug #55531) * *Security Fix*: *Note `EXPLAIN EXTENDED': explain. caused a server crash with some prepared statements. (Bug #54494) * *Security Fix*: In prepared-statement mode, *Note `EXPLAIN': explain. for a *Note `SELECT': select. from a derived table caused a server crash. (Bug #54488) * *InnoDB Storage Engine*: The server could crash with a high volume of concurrent *Note `LOCK TABLES': lock-tables. and *Note `UNLOCK TABLES': lock-tables. statements. (Bug #57345) * *InnoDB Storage Engine*: `InnoDB' incorrectly reported an error when a cascading foreign key constraint deleted more than 250 rows. (Bug #57255) * *InnoDB Storage Engine*: A `SELECT ... FOR UPDATE' statement affecting a range of rows in an `InnoDB' table could cause a crash in the debug version of the server. (Bug #56716) * *InnoDB Storage Engine*: Improved the performance of `UPDATE' operations on `InnoDB' tables, when only non-indexed columns are changed. (Bug #56340) * *InnoDB Storage Engine*: The server could crash on shutdown, if started with `--innodb-use-system-malloc=0'. (Bug #55627) * *InnoDB Storage Engine*: For an `InnoDB' table with an auto-increment column, the server could crash if the first statement that references the table after a server restart is a `SHOW CREATE TABLE' statement. (Bug #55277) * *InnoDB Storage Engine*: Setting the `PACK_KEYS=0' table option for an *Note `InnoDB': innodb-storage-engine. table prevented new indexes from being added to the table. (Bug #54606) * *InnoDB Storage Engine*: Changed the locking mechanism for the `InnoDB' data dictionary during `ROLLBACK' operations, to improve concurrency for `REPLACE' statements. (Bug #54538) * *InnoDB Storage Engine*: `InnoDB' transactions could be incorrectly committed during recovery, rather than rolled back, if the server crashed and was restarted after performing `ALTER TABLE...ADD PRIMARY KEY' on an `InnoDB' table, or some other operation that involves copying the entire table. (Bug #53756) * *Partitioning*: *Replication*: Attempting to execute *Note `LOAD DATA': load-data. on a partitioned `MyISAM' table while using statement-based logging mode caused the master to hang or crash. (Bug #51851) * *Partitioning*: Multi-table *Note `UPDATE': update. statements involving a partitioned *Note `MyISAM': myisam-storage-engine. table could cause this table to become corrupted. Not all tables affected by the *Note `UPDATE': update. needed to be partitioned for this issue to be observed. (Bug #55458) * *Partitioning*: *Note `EXPLAIN PARTITIONS': explain. returned bad estimates for range queries on partitioned *Note `MyISAM': myisam-storage-engine. tables. In addition, values in the `rows' column of *Note `EXPLAIN PARTITIONS': explain. output did not take partition pruning into account. (Bug #53806, Bug #46754) * *Replication*: Backticks used to enclose identifiers for savepoints were not preserved in the binary log, which could lead to replication failure when the identifier, stripped of backticks, could be misinterpreted, causing a syntax or other error. This could cause problems with MySQL application programs making use of generated savepoint IDs. If, for instance, `java.sql.Connection.setSavepoint()' is called without any parameters, Connector/J automatically generates a savepoint identifier consisting of a string of hexadecimal digits `0'-`F' encased in backtick (``') characters. If such an ID took the form ``NeN`' (where N represents a string of the decimal digits `0'-`9', and `e' is a literal uppercase or lowercase `E' character). Removing the backticks when writing the identifier into the binary log left behind a substring which the slave MySQL server tried to interpret as a floating point number, rather than as an identifier. The resulting syntax error caused loss of replication. (Bug #55961) See also Bug #55962. * When *Note `mysqld': mysqld. was started as a service on Windows and *Note `mysqld': mysqld. was writing the error log to a file (for example, if it was started with the `--log-error' option), the server reassign the file descriptors of the `stdout' and `stderr' streams to the file descriptor of the log file. On Windows, if `stdout' or `stderr' is not associated with an output stream, the file descriptor returns a negative value. Previously, this would cause the file descriptor reassignment to fail and the server to abort. To avoid this problem on Windows, `stdout' and `stderr' streams are now first assigned to the log file stream by opening this file. This causes `stdout' and `stderr' file descriptors to be nonzero and the server can successfully reassign them to the file descriptor of the log file. (Bug #56821) * Memory leaks detected by Valgrind were corrected. (Bug #56709) * If a query specified a *Note `DATE': datetime. or *Note `DATETIME': datetime. value in a format different from `'YYYY-MM-DD HH:MM:SS'', a greater-than-or-equal (`>=') condition matched only greater-than values in an indexed *Note `TIMESTAMP': datetime. column. (Bug #55779, Bug #50774, Bug #11758558) * If there was an active *Note `SELECT': select. statement, an error arising during trigger execution could cause a server crash. (Bug #55421) * With an *Note `UPDATE IGNORE': update. statement including a subquery that was evaluated using a temporary table, an error transferring the data from the temporary was ignored, causing an assertion to be raised. (Bug #54543) * Row subqueries producing no rows were not handled as `UNKNOWN' values in row comparison expressions. (Bug #54190) * The `max_length' metadata value of *Note `MEDIUMBLOB': blob. types was reported as 1 byte greater than the correct value. (Bug #53296) * In some cases, when the left part of a `NOT IN' subquery predicate was a row and contained `NULL' values, the query result was incorrect. (Bug #51070) * For some queries, the optimizer produced incorrect results using the Index Merge access method with *Note `InnoDB': innodb-storage-engine. tables. (Bug #50402) * *Note `EXPLAIN': explain. produced an incorrect `rows' value for queries evaluated using an index scan and that included `LIMIT', `GROUP BY', and `ORDER BY' on a computed column. (Bug #50394) * *Note `mysql_store_result()': mysql-store-result. and *Note `mysql_use_result()': mysql-use-result. are not for use with prepared statements and are not intended to be called following *Note `mysql_stmt_execute()': mysql-stmt-execute, but failed to return an error when invoked that way. (Bug #47485) * Using `REPAIR TABLE TABLE USE_FRM' on a `MERGE' table caused the server to crash. (Bug #46339) * A malformed packet sent by the server when the query cache was in use resulted in lost-connection errors. (Bug #42503) * *Note `CREATE TABLE': create-table. failed if a column referred to in an index definition and foreign key definition was in different lettercases in the two definitions. (Bug #39932)  File: manual.info, Node: news-5-1-51, Next: news-5-1-50, Prev: news-5-1-52, Up: news-5-1-x D.1.10 Changes in MySQL 5.1.51 (10 September 2010) -------------------------------------------------- *InnoDB Notes* * `InnoDB Plugin' has been upgraded to version 1.0.12. This version is considered of General Availability (GA) quality. In this release, the `InnoDB Plugin' is included in source and binary distributions, except RHEL3, RHEL4, SuSE 9 (x86, x86_64, ia64), and generic Linux RPM packages. It also does not work for FreeBSD 6 and HP-UX or for Linux on generic ia64. *Bugs fixed:* * *Security Fix*: During evaluation of arguments to extreme-value functions (such as `LEAST()' and `GREATEST()'), type errors did not propagate properly, causing the server to crash. (Bug #55826, CVE-2010-3833) * *Security Fix*: The server could crash after materializing a derived table that required a temporary table for grouping. (Bug #55568, CVE-2010-3834) * *Security Fix*: A user-variable assignment expression that is evaluated in a logical expression context can be precalculated in a temporary table for `GROUP BY'. However, when the expression value is used after creation of the temporary table, it was re-evaluated, not read from the table and a server crash resulted. (Bug #55564, CVE-2010-3835) * *Security Fix*: The `CONVERT_TZ()' function crashed the server when the timezone argument was an empty *Note `SET': set. column value. (Bug #55424) * *Security Fix*: Pre-evaluation of `LIKE' predicates during view preparation could cause a server crash. (Bug #54568, CVE-2010-3836) * *Security Fix*: `GROUP_CONCAT()' and `WITH ROLLUP' together could cause a server crash. (Bug #54476, CVE-2010-3837) * *Security Fix*: Queries could cause a server crash if the `GREATEST()' or `LEAST()' function had a mixed list of numeric and *Note `LONGBLOB': blob. arguments, and the result of such a function was processed using an intermediate temporary table. (Bug #54461, CVE-2010-3838) * *Security Fix*: Queries with nested joins could cause an infinite loop in the server when used from stored procedures and prepared statements. (Bug #53544, CVE-2010-3839) * *Security Fix*: The `PolyFromWKB()' function could crash the server when improper WKB data was passed to the function. (Bug #51875, CVE-2010-3840) * *Incompatible Change*: *Replication*: As of MySQL 5.5.6, handling of *Note `CREATE TABLE IF NOT EXISTS ... SELECT': create-table-select. statements has been changed for the case that the destination table already exists: * Previously, for *Note `CREATE TABLE IF NOT EXISTS ... SELECT': create-table-select, MySQL produced a warning that the table exists, but inserted the rows and wrote the statement to the binary log anyway. By contrast, *Note `CREATE TABLE ... SELECT': create-table-select. (without `IF NOT EXISTS') failed with an error, but MySQL inserted no rows and did not write the statement to the binary log. * MySQL now handles both statements the same way when the destination table exists, in that neither statement inserts rows or is written to the binary log. The difference between them is that MySQL produces a warning when `IF NOT EXISTS' is present and an error when it is not. This change in handling of `IF NOT EXISTS' results in an incompatibility for statement-based replication from a MySQL 5.1 master with the original behavior and a MySQL 5.5 slave with the new behavior. Suppose that *Note `CREATE TABLE IF NOT EXISTS ... SELECT': create-table-select. is executed on the master and the destination table exists. The result is that rows are inserted on the master but not on the slave. (Row-based replication does not have this problem.) To address this issue, statement-based binary logging for *Note `CREATE TABLE IF NOT EXISTS ... SELECT': create-table-select. is changed in MySQL 5.1 as of 5.1.51: * If the destination table does not exist, there is no change: The statement is logged as is. * If the destination table does exist, the statement is logged as the equivalent pair of *Note `CREATE TABLE IF NOT EXISTS': create-table-select. and *Note `INSERT ... SELECT': insert-select. statements. (If the *Note `SELECT': select. in the original statement is preceded by `IGNORE' or *Note `REPLACE': replace, the *Note `INSERT': insert. becomes *Note `INSERT IGNORE': insert. or *Note `REPLACE': replace, respectively.) This change provides forward compatibility for statement-based replication from MySQL 5.1 to 5.5 because when the destination table exists, the rows will be inserted on both the master and slave. To take advantage of this compatibility measure, the 5.1 server must be at least 5.1.51 and the 5.5 server must be at least 5.5.6. To upgrade an existing 5.1-to-5.5 replication scenario, upgrade the master first to 5.1.51 or higher. Note that this differs from the usual replication upgrade advice of upgrading the slave first. A workaround for applications that wish to achieve the original effect (rows inserted regardless of whether the destination table exists) is to use *Note `CREATE TABLE IF NOT EXISTS': create-table-select. and *Note `INSERT ... SELECT': insert-select. statements rather than *Note `CREATE TABLE IF NOT EXISTS ... SELECT': create-table-select. statements. Along with the change just described, the following related change was made: Previously, if an existing view was named as the destination table for *Note `CREATE TABLE IF NOT EXISTS ... SELECT': create-table-select, rows were inserted into the underlying base table and the statement was written to the binary log. As of MySQL 5.1.51 and 5.5.6, nothing is inserted or logged. (Bug #47442, Bug #47132, Bug #48814, Bug #49494) * *Incompatible Change*: Previously, if you flushed the logs using *Note `FLUSH LOGS': flush. or *Note `mysqladmin flush-logs': mysqladmin. and *Note `mysqld': mysqld. was writing the error log to a file (for example, if it was started with the `--log-error' option), it renamed the current log file with the suffix `-old', then created a new empty log file. This had the problem that a second log-flushing operation thus caused the original error log file to be lost unless you saved it under a different name. For example, you could use the following commands to save the file: shell> mysqladmin flush-logs shell> mv HOST_NAME.err-old BACKUP-DIRECTORY To avoid the preceding file-loss problem, renaming no longer occurs. The server merely closes and reopens the log file. To rename the file, you can do so manually before flushing. Then flushing the logs reopens a new file with the original file name. For example, you can rename the file and create a new one using the following commands: shell> mv HOST_NAME.err HOST_NAME.err-old shell> mysqladmin flush-logs shell> mv HOST_NAME.err-old BACKUP-DIRECTORY (Bug #29751) See also Bug #56821. * *Important Change*: *InnoDB Storage Engine*: The server could crash with an assertion, possibly leading to data corruption, while updating the primary key of an *Note `InnoDB': innodb-storage-engine. table containing BLOB or other columns requiring off-page storage. This fix applies to the *Note `InnoDB': innodb-storage-engine. Plugin in MySQL 5.1, and to *Note `InnoDB': innodb-storage-engine. 1.1 in MySQL 5.5. (Bug #55543) * *InnoDB Storage Engine*: When MySQL was restarted after a crash with the option `innodb_force_recovery=6', certain queries against `InnoDB' tables could fail, depending on `WHERE' or `ORDER BY' clauses. Usually in such a disaster recovery situation, you dump the entire table using a query without these clauses. During advanced troubleshooting, you might use queries with these clauses to diagnose the position of the corrupted data, or to recover data following the corrupted part. (Bug #55832) * *InnoDB Storage Engine*: The `CHECK TABLE' command could cause a time-consuming verification of the `InnoDB' adaptive hash index memory structure. Now this extra checking is only performed in binaries built for debugging. (Bug #55716) * *InnoDB Storage Engine*: A heavy workload with a large number of threads could cause a crash in the debug version of the server. (Bug #55699) * *InnoDB Storage Engine*: If the server crashed during a `RENAME TABLE' operation on an `InnoDB' table, subsequent crash recovery could fail. This problem could also affect an `ALTER TABLE' statement that caused a rename operation internally. (Bug #55027) * *InnoDB Storage Engine*: The server could crash when opening an *Note `InnoDB': innodb-storage-engine. table linked through foreign keys to a long chain of child tables. (Bug #54582) * *Partitioning*: When the storage engine used to create a partitioned table was disabled, attempting to drop the table caused the server to crash. (Bug #46086) * If a view was named as the destination table for `CREATE TABLE ... SELECT', the server produced a warning whether or not `IF NOT EXISTS' was used. Now it produces a warning only when `IF NOT EXISTS' is used, and an error otherwise. (Bug #55777) * After the fix for Bug#39653, the shortest available secondary index was used for full table scans. The primary clustered key was used only if no secondary index could be used. However, when the chosen secondary index includes all columns of the table being scanned, it is better to use the primary index because the amount of data to scan is the same but the primary index is clustered. This is now taken into account. (Bug #55656) * The server was not checking for errors generated during the execution of `Item::val_xxx()' methods when copying data to a group, order, or distinct temp table's row. (Bug #55580) * `ORDER BY' clauses that included user variable expressions could cause a debug assertion to be raised. (Bug #55565) * Assignment of *Note `InnoDB': innodb-storage-engine. scalar subquery results to a variable resulted in unexpected `S' locks in `READ COMMITTED' transation isolation level. (Bug #55382) * Queries involving predicates of the form `CONST NOT BETWEEN NOT_INDEXED_COLUMN AND INDEXED_COLUMN' could return incorrect data due to incorrect handling by the range optimizer. (Bug #54802) * `MIN()' or `MAX()' with a subquery argument could raise a debug assertion for debug builds or return incorrect data for nondebug builds. (Bug #54465) * `INFORMATION_SCHEMA' plugins with no `deinit()' method resulted in a memory leak. (Bug #54253) * After *Note `ALTER TABLE': alter-table. was used on a temporary transactional table locked by *Note `LOCK TABLES': lock-tables, any later attempts to execute *Note `LOCK TABLES': lock-tables. or *Note `UNLOCK TABLES': lock-tables. caused a server crash. (Bug #54117) * *Note `INSERT IGNORE INTO ... SELECT': insert-select. statements could cause a debug assertion to be raised. (Bug #54106) * *Note `INFORMATION_SCHEMA.COLUMNS': columns-table. reported incorrect precision for `BIGINT UNSIGNED' columns. (Bug #53814) * The fix for Bug#30234 caused the server to reject the `DELETE tbl_name.* ...' Access compatibility syntax for multiple-table *Note `DELETE': delete. statements. (Bug #53034) * *Note `XA START': xa. had a race condition that could cause a server crash. (Bug #51855) * Enumeration plugin variables were subject to a type casting error, causing inconsistent results between different platforms. (Bug #42144) * A PKG install on Solaris put some files in incorrect locations. (Bug #31058) * Problems in the atomic operations implementation could lead to server crashes. (Bug #22320, Bug #52261)  File: manual.info, Node: news-5-1-50, Next: news-5-1-49sp1, Prev: news-5-1-51, Up: news-5-1-x D.1.11 Changes in MySQL 5.1.50 (03 August 2010) ----------------------------------------------- *icc Notes* * This is the final release of MySQL 5.1 for which Generic Linux MySQL binary packages built with the `icc' compiler on x86 and x86_64 will be offered. These were previously produced as an alternative to our main packages built using `gcc', as they provided noticeable performance benefits. In recent times the performance differences have diminished and build and runtime problems have surfaced, thus it is no longer viable to continue producing them. We continue to use the `icc' compiler to produce our distribution-specific RPM packages on ia64. *InnoDB Notes* * `InnoDB Plugin' has been upgraded to version 1.0.11. This version is considered of General Availability (GA) quality. In this release, the `InnoDB Plugin' is included in source and binary distributions, except RHEL3, RHEL4, SuSE 9 (x86, x86_64, ia64), generic Linux RPM packages, and any builds produced with the `icc' compiler. It also does not work for FreeBSD 6 and HP-UX or for Linux on generic ia64. *Bugs fixed:* * *Important Change*: *Replication*: The *Note `LOAD DATA INFILE': load-data. statement is now considered unsafe for statement-based replication. When using statement-based logging mode, the statement now produces a warning; when using mixed-format logging, the statement is made using the row-based format. (Bug #34283) * *InnoDB Storage Engine*: The server could crash on shutdown, if started with `--innodb-use-system-malloc=0'. (Bug #55581, Bug #11762927) * *InnoDB Storage Engine*: The database server could crash when renaming a table that had active transactions. (This issue only affected the database server when built for debugging.) (Bug #54453) * *InnoDB Storage Engine*: The server could crash during the recovery phase of startup, if it previously crashed while inserting `BLOB' or other large columns that use off-page storage into an `InnoDB' table created with `ROW_FORMAT=REDUNDANT' or `ROW_FORMAT=COMPACT'. (Bug #54408) * *InnoDB Storage Engine*: For an `InnoDB' table created with `ROW_FORMAT=COMPRESSED' or `ROW_FORMAT=DYNAMIC', a query using the `READ UNCOMMITTED' isolation level could cause the server to stop with an assertion error, if `BLOB' or other large columns that use off-page storage were being inserted at the same time. (Bug #54358) * *Partitioning*: *Note `UPDATE': update. and *Note `INSERT': insert. statements affecting partitioned tables performed poorly when using row-based replication. (Bug #52517) * *Partitioning*: *Note `INSERT ON DUPLICATE KEY UPDATE': insert. statements performed poorly on tables having many partitions. This was because the handler function for reading a row from a specific index was not optimized in the partitioning handler. (Bug #52455) * *Replication*: When using the row-based logging format, a failed *Note `CREATE TABLE ... SELECT': create-table. statement was written to the binary log, causing replication to break if the failed statement was later re-run on the master. In such cases, a *Note `DROP TABLE ... IF EXIST': drop-table. statement is now logged in the event that a *Note `CREATE TABLE ... SELECT': create-table. fails. (Bug #55625) * `GROUP BY' operations used `max_sort_length' inconsistently. (Bug #55188) * Building MySQL on Solaris 8 x86 failed when using Sun Studio due to `gcc' inline assembly code. (Bug #55061) * In debug builds, an assertion could be raised when the server tried to send an OK packet to the client after having failed to detect errors during processing of the `WHERE' condition of an *Note `UPDATE': update. statement. (Bug #54734) * A join with an aggregated function and impossible `WHERE' condition returned an extra row. (Bug #54416) * A client could supply data in chunks to a prepared statement parameter other than of type *Note `TEXT': blob. or *Note `BLOB': blob. using the *Note `mysql_stmt_send_long_data()': mysql-stmt-send-long-data. C API function (or `COM_STMT_SEND_LONG_DATA' command). This led to a crash because other data types are not valid for long data. (Bug #54041) * *Note `mysql_secure_installation': mysql-secure-installation. did not properly identify local accounts and could incorrectly remove nonlocal `root' accounts. (Bug #54004) * Portability problems in *Note `SHOW STATUS': show-status. could lead to incorrect results on some platforms. (Bug #53493) * Builds of MySQL generated a large number of warnings. (Bug #53445) * With `lower_case_table_names' set to a nonzero value, searches for table or database names in `INFORMATION_SCHEMA' tables could produce incorrect results. (Bug #53095) * The ABI check for MySQL failed to compile with `gcc' 4.5. (Bug #52514) * *Note `mysql_secure_installation': mysql-secure-installation. sometimes failed to locate the *Note `mysql': mysql. client. (Bug #52274) * Reading a `ucs2' data file with *Note `LOAD DATA INFILE': load-data. was subject to three problems. 1) Incorrect parsing of the file as `ucs2' data, resulting in incorrect length of the parsed string. This is fixed by truncating the invalid trailing bytes (incomplete multibyte characters) when reading from the file. 2) Reads from a proper `ucs2' file did not recognize newline characters. This is fixed by first checking whether a byte is a newline (or any other special character) before reading it as a part of a multibyte character. 3) When using user variables to hold column data, the character set of the user variable was set incorrectly to the database charset. This is fixed by setting it to the character set specified in the *Note `LOAD DATA INFILE': load-data. statement, if any. (Bug #51876) * Searches in `INFORMATION_SCHEMA' tables for rows matching a nonexistent database produced an error instead of an empty query result. (Bug #49542) * On FreeBSD, memory mapping for *Note `MERGE': merge-storage-engine. tables could fail if underlying tables were empty. (Bug #47139) * The `my_like_range_XXX()' functions returned badly formed maximum strings for Asian character sets, which caused problems for storage engines. (Bug #45012) * A debugging assertion could be raised after a write failure to a closed socket. (Bug #42496) * An assertion failure occurred within yaSSL for very long keys. (Bug #29784) See also Bug #53463.  File: manual.info, Node: news-5-1-49sp1, Next: news-5-1-49, Prev: news-5-1-50, Up: news-5-1-x D.1.12 Release Notes for MySQL Enterprise 5.1.49sp1 [QSP] (28 September 2010) ----------------------------------------------------------------------------- This is a _Service Pack_ release of the MySQL Enterprise Server 5.1. *Bugs fixed:* * Building MySQL on Solaris 8 x86 failed when using Sun Studio due to `gcc' inline assembly code. (Bug #55061) * A client could supply data in chunks to a prepared statement parameter other than of type *Note `TEXT': blob. or *Note `BLOB': blob. using the *Note `mysql_stmt_send_long_data()': mysql-stmt-send-long-data. C API function (or `COM_STMT_SEND_LONG_DATA' command). This led to a crash because other data types are not valid for long data. (Bug #54041)  File: manual.info, Node: news-5-1-49, Next: news-5-1-48, Prev: news-5-1-49sp1, Up: news-5-1-x D.1.13 Changes in MySQL 5.1.49 (09 July 2010) --------------------------------------------- *InnoDB Notes* * `InnoDB Plugin' has been upgraded to version 1.0.10. This version is considered of General Availability (GA) quality. In this release, the `InnoDB Plugin' is included in source and binary distributions, except RHEL3, RHEL4, SuSE 9 (x86, x86_64, ia64), generic Linux RPM packages, and any builds produced with the `icc' compiler. It also does not work for FreeBSD 6 and HP-UX or for Linux on generic ia64. *Bugs fixed:* * *InnoDB Storage Engine*: *Security Fix*: After changing the values of the `innodb_file_format' or `innodb_file_per_table' configuration parameters, DDL statements could cause a server crash. (Bug #55039, CVE-2010-3676) * *Security Fix*: Joins involving a table with a unique *Note `SET': set. column could cause a server crash. (Bug #54575, CVE-2010-3677) * *Security Fix*: Incorrect handling of `NULL' arguments could lead to a crash for `IN()' or `CASE' operations when `NULL' arguments were either passed explicitly as arguments (for `IN()') or implicitly generated by the `WITH ROLLUP' modifier (for `IN()' and `CASE'). (Bug #54477, CVE-2010-3678) * *Security Fix*: A malformed argument to the *Note `BINLOG': binlog. statement could result in Valgrind warnings or a server crash. (Bug #54393, CVE-2010-3679) * *Security Fix*: Use of `TEMPORARY' *Note `InnoDB': innodb-storage-engine. tables with nullable columns could cause a server crash. (Bug #54044, CVE-2010-3680) * *Security Fix*: The server could crash if there were alternate reads from two indexes on a table using the *Note `HANDLER': handler. interface. (Bug #54007, CVE-2010-3681) * *Security Fix*: Using *Note `EXPLAIN': explain. with queries of the form `SELECT ... UNION ... ORDER BY (SELECT ... WHERE ...)' could cause a server crash. (Bug #52711, CVE-2010-3682) * *Security Fix*: *Note `LOAD DATA INFILE': load-data. did not check for SQL errors and sent an OK packet even when errors were already reported. Also, an assert related to client/server protocol checking in debug servers sometimes was raised when it should not have been. (Bug #52512, CVE-2010-3683) * *InnoDB Storage Engine*: An *Note `ALTER TABLE': alter-table. statement could convert an `InnoDB' compressed table (with `row_format=compressed') back to an uncompressed table (with `row_format=compact'). (Bug #54679) * *InnoDB Storage Engine*: `InnoDB' could issue an incorrect message on startup, if tables were created under the setting `innodb_file_per_table=ON'. The message was of the form `InnoDB: Warning: allocated tablespace N, old maximum was 0 'and is no longer displayed during restarts after you have upgraded the MySQL server and created at least one `InnoDB' table with `innodb_file_per_table=ON'. If you continue to encounter this message, you might have corruption in your shared tablespace; if so, back up and reload your data. (Bug #54658) * *InnoDB Storage Engine*: Fast index creation in the `InnoDB' Plugin could fail, leaving the new secondary index corrupted. (Bug #54330) * *InnoDB Storage Engine*: Some combinations of `SELECT' and `SELECT FOR UPDATE' statements could fail with errors about locks, or incorrectly release a row lock during a semi-consistent read (http://dev.mysql.com/doc/innodb-plugin/1.0/en/glossary.html#glos_semi_consistent_read) operation. (Bug #53674) * *InnoDB Storage Engine*: Performing large numbers of *Note `RENAME TABLE': rename-table. statements caused excessive memory use. (Bug #47991) * *InnoDB Storage Engine*: The mechanism that checks if there is enough space for redo logs was improved, reducing the chance of encountering this message: `ERROR: the age of the last checkpoint is X, which exceeds the log group capacity Y'. (Bug #39168) * *Replication*: When using unique keys on `NULL' columns in row-based replication, the slave sometimes chose the wrong row when performing an update. This happened because a table having a unique key on such a column could have multiple rows containing `NULL' for the column used by the unique key, and the slave merely picked the first row containing `NULL' in that column. (Bug #53893) * *Replication*: *Note `FLUSH LOGS': flush. could in some circumstances crash the server. This occurred because the I/O thread could concurrently access the relay log I/O cache while another thread was performing the *Note `FLUSH LOGS': flush, which closes and reopens the relay log and, while doing so, initializes (or re-initializes) its I/O cache. This could cause problems if some other thread (in this case, the I/O thread) is accessing it at the same time. Now the thread performing the *Note `FLUSH LOGS': flush. takes a lock on the relay log before actually flushing it. (Bug #53657) See also Bug #50364. * *Replication*: Two related issues involving temporary tables and transactions were introduced by a fix made in MySQL 5.1.37: 1. When a temporary table was created or dropped within a transaction, any failed statement that following the *Note `CREATE TEMPORARY TABLE': create-table. or *Note `DROP TEMPORARY TABLE': drop-table. statement triggered a rollback, which caused the slave diverge from the master. 2. When a *Note `CREATE TEMPORARY TABLE ... SELECT * FROM ...': create-table. statement was executed within a transaction in which only tables using transactional storage engines were used and the transaction was rolled back at the end, the changes--including the creation of the temporary table--were not written to the binary log. The current fix restores the correct behavior in both of these cases. (Bug #53560) This regression was introduced by Bug #43929. * *Replication*: When `CURRENT_USER()' or `CURRENT_USER' was used to supply the name and host of the affected user or of the definer in any of the statements *Note `DROP USER': drop-user, *Note `RENAME USER': rename-user, *Note `GRANT': grant, *Note `REVOKE': revoke, and *Note `ALTER EVENT': alter-event, the reference to `CURRENT_USER()' or `CURRENT_USER' was not expanded when written to the binary log. This resulted in `CURRENT_USER()' or `CURRENT_USER' being expanded to the user and host of the slave SQL thread on the slave, thus breaking replication. Now `CURRENT_USER()' and `CURRENT_USER' are expanded prior to being written to the binary log in such cases, so that the correct user and host are referenced on both the master and the slave. (Bug #48321) * A signal-handler redefinition for `SIGUSR1' was removed. The redefinition could cause the server to encounter a kernel deadlock on Solaris when there are many active threads. Other POSIX platforms might also be affected. (Bug #54667) * The `make_binary_distribution' target to `make' could fail on some platforms because the lines generated were too long for the shell. (Bug #54590) * The server failed to disregard sort order for some zero-length tuples, leading to an assertion failure. (Bug #54459) * The default value of `myisam_max_extra_sort_file_size' (http://dev.mysql.com/doc/refman/5.0/en/server-system-variables.html#sysvar_myisam_max_extra_sort_file_size) could be higher than the maximum accepted value, leading to warnings upon the server start. (Bug #54457) * Inconsistent checking of the relationship between *Note `SHOW': show. statements and `INFORMATION_SCHEMA' queries caused such queries to fail sometimes. (Bug #54422) * If a session tried to drop a database containing a table opened with *Note `HANDLER': handler. in another session, any `DATABASE' statement (`CREATE', `DROP', `ALTER') executed by that session produced a deadlock. (Bug #54360) * Builds of the embedded *Note `mysqld': mysqld. would fail due to a missing element of the `struct NET'. (Bug #53908, Bug #53912) * The definition of the `MY_INIT' macro in `my_sys.h' included an extraneous semicolon, which could cause compilation failure. (Bug #53906) * A client with automatic reconnection enabled saw the error message `Lost connection to MySQL server during query' if the connection was lost between the *Note `mysql_stmt_prepare()': mysql-stmt-prepare. and *Note `mysql_stmt_execute()': mysql-stmt-execute. C API functions. However, *Note `mysql_stmt_errno()': mysql-stmt-errno. returned 0, not the corresponding error number 2013. (Bug #53899) * Queries that used `MIN()' or `MAX()' on indexed columns could be optimized incorrectly. (Bug #53859) * The `Lock_time' value in the slow query log was negative for stored routines. (Bug #53191) * The results of some `ORDER BY ... DESC' queries were sorted incorrectly. (Bug #51431) * `Index Merge' between three indexes could return incorrect results. (Bug #50389) * The server could crash with an out of memory error when trying to parse a query that was too long to fit in memory. Now the parser rejects such queries with an `ER_OUT_OF_RESOURCES' error. (Bug #42064) * Sort-`index_merge' for join tables other than the first table used excessive memory. (Bug #41660) * Valgrind warnings in the *Note `InnoDB': innodb-storage-engine. `compare_record()' function were corrected. (Bug #38999) * *Note `mysqld': mysqld. could fail during execution when using SSL. (Bug #34236) * The behavior of the RPM upgrade installation has changed. During an upgrade installation using the RPM packages, if the MySQL server is running when the upgrade occurs, the server is stopped, the upgrade occurs, and server is restarted. If the server is not already running when the RPM upgrade occurs, the server is not started at the end of the upgrade. The boot scripts for MySQL are installed in the appropriate directories in `/etc', so the MySQL server will be restarted automatically at the next machine reboot. (Bug #27072)  File: manual.info, Node: news-5-1-48, Next: news-5-1-47, Prev: news-5-1-49, Up: news-5-1-x D.1.14 Changes in MySQL 5.1.48 (02 June 2010) --------------------------------------------- *InnoDB Notes* * `InnoDB Plugin' has been upgraded to version 1.0.9. This version is considered of General Availability (GA) quality. In this release, the `InnoDB Plugin' is included in source and binary distributions, except RHEL3, RHEL4, SuSE 9 (x86, x86_64, ia64), generic Linux RPM packages, and any builds produced with the `icc' compiler. It also does not work for FreeBSD 6 and HP-UX or for Linux on generic ia64. *Functionality added or changed:* * The `Rows_examined' value in slow query log rows now is nonzero for *Note `UPDATE': update. and *Note `DELETE': delete. statements that modify rows. (Bug #49756) *Bugs fixed:* * *Important Change*: *Replication*: *Note `MyISAM': myisam-storage-engine. transactions replicated to a transactional slave left the slave in an unstable condition. This was due to the fact that, when replicating from a nontransactional storage engine to a transactional engine with `autocommit' disabled, no *Note `BEGIN': commit. and *Note `COMMIT': commit. statements were written to the binary log; thus, on the slave, a never-ending transaction was started. The fix for this issue includes enforcing `autocommit' mode on the slave by replicating all `autocommit=1' statements from the master. (Bug #29288) * *InnoDB Storage Engine*: *Replication*: Reading from a table that used a self-logging storage engine and updating a table that used a transactional engine (such as `InnoDB') generated changes that were written to the binary log using statement format which could make slaves diverge. However, when using mixed logging format, such changes should be written to the binary log using row format. (This issue did not occur when reading from tables using a self-logging engine and updating `MyISAM' tables, as this was already handled by checking for combinations of non-transactional and transactional engines.) Now such statements are classified as unsafe, and in mixed mode, cause a switch to row-based logging. (Bug #49019) * *InnoDB Storage Engine*: The server could crash with a message `InnoDB: Assertion failure in thread NNNN', typically during shutdown on a Windows system. (Bug #53947) * *InnoDB Storage Engine*: Adding a unique key on multiple columns, where one of the columns is null, could mistakenly report duplicate key errors. (Bug #53290) * *InnoDB Storage Engine*: Fixed a checksum error reported for compressed tables when the `--innodb_checksums' option is enabled. Although the message stated that the table was corrupted, the table is actually fine after the fix. (Bug #53248) * *InnoDB Storage Engine*: Corrected the handling of the setting `innodb_change_buffering=default'. (The appropriate default value is different between MySQL 5.1 and 5.5.) (Bug #53165) * *InnoDB Storage Engine*: Multi-statement execution could fail with an error about foreign key constraints. This problem could affect calls to `mysql_query()' and `mysql_real_query()', and `CALL' statements that invoke stored procedures. (Bug #48024) * *InnoDB Storage Engine*: If a crash occurs while creating an index using the InnoDB `Fast Index Creation' mechanism, the partially created index is dropped during the crash recovery processing when the database is restarted. * *Partitioning*: *Note `ALTER TABLE': alter-table-partition-operations. statements that cause table partitions to be renamed or dropped (such as `ALTER TABLE ... ADD PARTITION', `ALTER TABLE ... DROP PARTITION', and `ALTER TABLE ... REORGANIZE PARTITION') -- when run concurrently with queries against the *Note `INFORMATION_SCHEMA.PARTITIONS': partitions-table. table -- could fail, cause the affected partitioned tables to become unusable, or both. This was due to the fact that the `INFORMATION_SCHEMA' database ignored the name lock imposed by the *Note `ALTER TABLE': alter-table. statement on the partitions affected. In particular, this led to problems with *Note `InnoDB': innodb-storage-engine. tables, because *Note `InnoDB': innodb-storage-engine. would accept the rename operation, but put it in a background queue, so that subsequent rename operations failed when *Note `InnoDB': innodb-storage-engine. was unable to find the correct partition. Now, `INFORMATION_SCHEMA' honors name locks imposed by ongoing *Note `ALTER TABLE': alter-table. statements that cause partitions to be renamed or dropped. (Bug #50561) See also Bug #47343, Bug #45808. * *Partitioning*: It was possible to execute a `CREATE TEMPORARY TABLE tmp LIKE pt' statement, where `pt' is a partitioned table, even though partitioned temporary tables are not permitted, which caused the server to crash. Now a check is performed to prevent such statements from being executed. (Bug #49477) * *Partitioning*: When attempting to perform DDL on a partitioned table and the table's `.par' file could not be found, the server returned the inaccurate error message `Out of memory; restart server and try again (needed 2 bytes)'. Now in such cases, the server returns the error `Failed to initialize partitions from .par file'. (Bug #49161) * *Replication*: In some cases, attempting to update a column with a value of an incompatible type resulted in a mismatch between master and slave because the column value was set to its implicit default value on the master (as expected), but the same column on the slave was set to `NULL'. (Bug #52868) * *Replication*: When using a non-transactional table on the master with autocommit disabled, no *Note `COMMIT': commit. was recorded in the binary log following a statement affecting this table. If the slave's copy of the table used a transactional storage engine, the result on the slave was as though a transaction had been started, but never completed. (Bug #49522) See also Bug #29288. * Valgrind warnings resulting from passing incomplete *Note `DATETIME': datetime. values to the `TIMESTAMP()' function were corrected. (Bug #53942) * *Note `UPDATE': update. on an *Note `InnoDB': innodb-storage-engine. table modifying the same index that was used to satisfy the `WHERE' condition could trigger a debug assertion under some circumstances. (Bug #53830) * MySQL incorrectly processed *Note `ALTER DATABASE `#mysql50#` UPGRADE DATA DIRECTORY NAME': alter-database. where was `.', `..', or a sequence starting with `./' or `../'. It used the server data directory (that contains other regular databases) as the database directory. (Bug #53804, CVE-2010-2008) * *Note `InnoDB': innodb-storage-engine. crashed when replacing duplicates in a table after a fast *Note `ALTER TABLE': alter-table. added a unique index. (Bug #53592) * For *Note `InnoDB': innodb-storage-engine. tables, the error handler for a fast *Note `CREATE INDEX': create-index. did not reset the error state of the transaction before attempting to undo a failed operation, resulting in a crash. (Bug #53591) * For single-table *Note `DELETE': delete. statements that used quick select and index scan simultaneously caused a server crash or assertion failure. (Bug #53450) * Incorrect results could be returned for `LEFT JOIN' of *Note `InnoDB': innodb-storage-engine. tables with an impossible `WHERE' condition. (Bug #53334) * Setting the `innodb_change_buffering' system variable to `DEFAULT' produced an incorrect result. (Bug #53165) * *Note `mysqldump': mysqldump. and *Note `SELECT ... INTO OUTFILE': select. truncated long *Note `BLOB': blob. and *Note `TEXT': blob. values to 766 bytes. (Bug #53088) * In the debug version of the server, the `FreeState()' function could in some circumstances be called twice, leading to an assertion failure. (Bug #52884) * Aggregate functions could incorrectly return `NULL' in outer join queries. (Bug #52051) * For outer joins, the optimizer could fail to properly calculate table dependencies. (Bug #52005) * The Loose Index Scan optimization method assumed that it could depend on the partitioning engine to maintain interval endpoint information, as if it were a storage engine. (Bug #50939) * Calculation of intervals for Event Scheduler events was not portable. (Bug #50087) * Selecting from *Note `INFORMATION_SCHEMA.ROUTINES': routines-table. or `INFORMATION_SCHEMA.PARAMETERS' (http://dev.mysql.com/doc/refman/5.5/en/parameters-table.html) resulted in a memory leak. (Bug #48729) * On Intel x86 machines, the optimizer could choose different execution plans for a query depending on the compiler version and optimization flags used to build the server binary. (Bug #48537) * When the transaction isolation level was `REPEATABLE READ' and binary logging used statement or mixed format, *Note `SELECT': select. statements with subqueries referencing *Note `InnoDB': innodb-storage-engine. tables unnecessarily acquired shared locks on rows in these tables. (Bug #46947) * Using an initial command with *Note `mysql_options(..., MYSQL_INIT_COMMAND, ...)': mysql-options. that generated multiple result sets (such as a stored procedure or a multi-statement command) left the connection unusable. (Bug #42373)  File: manual.info, Node: news-5-1-47, Next: news-5-1-46sp1, Prev: news-5-1-48, Up: news-5-1-x D.1.15 Changes in MySQL 5.1.47 (06 May 2010) -------------------------------------------- *InnoDB Notes* * `InnoDB Plugin' has been upgraded to version 1.0.8. This version is considered of General Availability (GA) quality. In this release, the `InnoDB Plugin' is included in source and binary distributions, except RHEL3, RHEL4, SuSE 9 (x86, x86_64, ia64), and generic Linux RPM packages. It also does not work for FreeBSD 6 and HP-UX or for Linux on generic ia64. *Functionality added or changed:* * *InnoDB Storage Engine*: *Note `InnoDB': innodb-storage-engine. stores redo log records in a hash table during recovery. On 64-bit systems, this hash table was 1/8 of the buffer pool size. To reduce memory usage, the dimension of the hash table was reduced to 1/64 of the buffer pool size (or 1/128 on 32-bit systems). (Bug #53122) *Bugs fixed:* * *Performance*: *InnoDB Storage Engine*: Deadlock detection could be a bottleneck in *Note `InnoDB': innodb-storage-engine. processing, if many transactions attempted to update the same row simultaneously. The algorithm has been improved to enhance performance and scalability, in the InnoDB Plugin for MySQL 5.1, and in InnoDB 1.1 for MySQL 5.5. (Bug #49047) * *Security Fix*: The server failed to check the table name argument of a `COM_FIELD_LIST' command packet for validity and compliance to acceptable table name standards. This could be exploited to bypass almost all forms of checks for privileges and table-level grants by providing a specially crafted table name argument to `COM_FIELD_LIST'. In MySQL 5.0 and above, this permitted an authenticated user with `SELECT' privileges on one table to obtain the field definitions of any table in all other databases and potentially of other MySQL instances accessible from the server's file system. Additionally, for MySQL version 5.1 and above, an authenticated user with `DELETE' or `SELECT' privileges on one table could delete or read content from any other table in all databases on this server, and potentially of other MySQL instances accessible from the server's file system. (Bug #53371, CVE-2010-1848) * *Security Fix*: The server was susceptible to a buffer-overflow attack due to a failure to perform bounds checking on the table name argument of a `COM_FIELD_LIST' command packet. By sending long data for the table name, a buffer is overflown, which could be exploited by an authenticated user to inject malicious code. (Bug #53237, CVE-2010-1850) * *Security Fix*: The server could be tricked into reading packets indefinitely if it received a packet larger than the maximum size of one packet. (Bug #50974, CVE-2010-1849) * *Important Change*: *Replication*: When invoked, *Note `CHANGE MASTER TO': change-master-to. and *Note `SET GLOBAL sql_slave_skip_counter': set-global-sql-slave-skip-counter. now cause information to be written to the error log about the slave's state prior to execution of the statement. For *Note `CHANGE MASTER TO': change-master-to, this information includes the previous values of `MASTER_HOST', `MASTER_PORT', `MASTER_LOG_FILE', and `MASTER_LOG_POS'. For *Note `SET GLOBAL sql_slave_skip_counter': set-global-sql-slave-skip-counter, this information includes the previous values of `RELAY_LOG_FILE', `RELAY_LOG_POS', and `sql_slave_skip_counter'. (Bug #43406, Bug #43407) * *InnoDB Storage Engine*: When reporting a foreign key constraint violation during *Note `INSERT': insert, *Note `InnoDB': innodb-storage-engine. could display uninitialized data for the `DB_TRX_ID' and `DB_ROLL_PTR' system columns. (Bug #53202) * *InnoDB Storage Engine*: The values of `innodb_buffer_pool_pages_total' and `innodb_buffer_pool_pages_misc' in the `information_schema.global_status' table could be computed incorrectly. (Bug #52983) * *InnoDB Storage Engine*: *Note `InnoDB': innodb-storage-engine. page splitting could enter an infinite loop for compressed tables. (Bug #52964) * *InnoDB Storage Engine*: An overly strict assertion could fail during the purge of delete-marked records in `DYNAMIC' or `COMPRESSED' *Note `InnoDB': innodb-storage-engine. tables that contain column prefix indexes. (Bug #52746) * *InnoDB Storage Engine*: *Note `InnoDB': innodb-storage-engine. attempted to choose off-page storage without ensuring that there was an `off-page storage' flag in the record header. To correct this, in `DYNAMIC' and `COMPRESSED' formats, *Note `InnoDB': innodb-storage-engine. stores locally any non-*Note `BLOB': blob. columns having a maximum length not exceeding 256 bytes. This is because there is no room for the `external storage' flag when the maximum length is 255 bytes or less. This restriction trivially holds in `REDUNDANT' and `COMPACT' formats, because there *Note `InnoDB': innodb-storage-engine. always stores locally columns having a length up to `local_len' = 788 bytes. (Bug #52745) * *InnoDB Storage Engine*: Connections waiting for an `InnoDB' row lock ignored *Note `KILL': kill. until the row lock wait ended. Now, *Note `KILL': kill. during lock wait results in `query interrupted' instead of `lock wait timeout exceeded'. The corresponding transaction is rolled back. (Bug #51920) * *InnoDB Storage Engine*: `InnoDB Plugin' checks to see whether a row could possibly exceed the maximum size if all columns are fully used. This produced `Row size too large' errors for some tables that could be created with the built-in `InnoDB'. Now the check is only done when `innodb_strict_mode' is enabled or if the table is dynamic or compressed. (Bug #50495) * *InnoDB Storage Engine*: A mismatch between index information maintained within the `.frm' files and the corresponding information in the InnoDB system tablespace could produce this error: `[ERROR] Index INDEX of TABLE has N columns unique inside InnoDB, but MySQL is asking statistics for M columns. Have you mixed up .frm files from different installations?' (Bug #44571) * *Replication*: The failure of a *Note `REVOKE': revoke. statement was logged with the wrong error code, causing replication slaves to stop even when the failure was expected on the master. (Bug #51987) * Certain path names passed to `LOAD_FILE()' could cause a server crash. (Bug #53417) * Semi-consistent read was implemented for *Note `InnoDB': innodb-storage-engine. to address Bug#3300. Semi-consistent reads do not block when a nonmatching record is already locked by some other transaction. If the record is not locked, a lock is acquired, but is released if the record does not match the `WHERE' condition. However, semi-consistent read was attempted even for *Note `UPDATE': update. statements having a `WHERE' condition of the form `pk_col1=constant1, ..., pk_colN=constantN'. Some code that was designed with the assumption that semi-consistent read would be only attempted on table scans, failed. (Bug #52663) * Setting `@@GLOBAL.debug' to an empty string failed to clear the current debug settings. (Bug #52629) * A memory leak occurred due to missing deallocation of the `comparators' array (a member of the `Arg_comparator' class). (Bug #52124) * For debug builds, creating a view containing a subquery that might require collation adjustment caused an assertion to be raised. For example, this could occur if some items had different collations but the result collation could be adjusted to the one of them. (Bug #52120) * Locking involving the `LOCK_plugin', `LOCK_global_system_variables', and `LOCK_status' mutexes could deadlock. (Bug #51591) * *Note `InnoDB': innodb-storage-engine. fast index creation could incorrectly use a table copy in some cases. (Bug #50946) * A syntactically invalid trigger could cause the server to crash when trying to list triggers. (Bug #50755) * Setting `--secure-file-priv' to the empty string left the value unaffected. (Bug #50373) * In MySQL 5.1, `READ COMMITTED' was changed to use less locking due to the availability of row based binary logging (see the Note under `READ COMMITTED' at *Note set-transaction::). However, `READ UNCOMMITTED' did not have the same change, so it was using more locks than the higher isolation level, which is unexpected. This was changed so that `READ UNCOMMITTED' now also uses the lesser amount of locking and has the same restrictions for binary logging. (Bug #48607) * *Note `EXPLAIN': explain. could cause a server crash for some queries with subqueries. (Bug #48419) * On Windows, the server failed to find a description for Event ID 100. (Bug #48042) * For updates to `InnoDB' tables, *Note `TIMESTAMP': datetime. columns could be updated even when no values actually changed. (Bug #47453) * *Note `mysqld_safe': mysqld-safe. did not always pass `--open-files-limit' through to *Note `mysqld': mysqld. *Note `mysqld_safe': mysqld-safe. did not treat dashes and underscores as equivalent in option names. (Bug #47095) * If the server is started with `--skip-grant-tables', plugin loading and unloading should be prohibited, but the server failed to reject *Note `INSTALL PLUGIN': install-plugin. and *Note `UNINSTALL PLUGIN': uninstall-plugin. statements. (Bug #46261) * `InnoDB' could fail to create a unique index on `NULL' columns. (Bug #41904) * Storage engine plugins on Windows could've been built with a definition of `time_t' which was different from the server expectations. The difference could cause affected plugins to crash. In addition, the use of the `time_t' type in the storage engine API layer has been enforced. (Bug #39802, Bug #40092) * When using *Note `UNINSTALL PLUGIN': uninstall-plugin. to remove a loaded plugin, open tables and connections caused *Note `mysqld': mysqld. to hang until the open connections had been closed. (Bug #39053) * 1) In rare cases, if a thread was interrupted during a *Note `FLUSH PRIVILEGES': flush. operation, a debug assertion occurred later due to improper diagnostics area setup. 2) A *Note `KILL': kill. operation could cause a console error message referring to a diagnostic area state without first ensuring that the state existed. (Bug #33982)  File: manual.info, Node: news-5-1-46sp1, Next: news-5-1-46, Prev: news-5-1-47, Up: news-5-1-x D.1.16 Release Notes for MySQL Enterprise 5.1.46sp1 [QSP] (23 June 2010) ------------------------------------------------------------------------ This is a _Service Pack_ release of the MySQL Enterprise Server 5.1. *Important*: If you will be using the plugin version of *Note `InnoDB': innodb-storage-engine, we recommend that you use MySQL 5.1.48 or later instead of 5.1.46sp1. This is because 5.1.46sp1 contains the first production-ready version and the later version has fixes for some of the bugs found during more widespread production use. *Bugs fixed:* * *Security Fix*: The server failed to check the table name argument of a `COM_FIELD_LIST' command packet for validity and compliance to acceptable table name standards. This could be exploited to bypass almost all forms of checks for privileges and table-level grants by providing a specially crafted table name argument to `COM_FIELD_LIST'. In MySQL 5.0 and above, this permitted an authenticated user with `SELECT' privileges on one table to obtain the field definitions of any table in all other databases and potentially of other MySQL instances accessible from the server's file system. Additionally, for MySQL version 5.1 and above, an authenticated user with `DELETE' or `SELECT' privileges on one table could delete or read content from any other table in all databases on this server, and potentially of other MySQL instances accessible from the server's file system. (Bug #53371, CVE-2010-1848) * *Security Fix*: The server was susceptible to a buffer-overflow attack due to a failure to perform bounds checking on the table name argument of a `COM_FIELD_LIST' command packet. By sending long data for the table name, a buffer is overflown, which could be exploited by an authenticated user to inject malicious code. (Bug #53237, CVE-2010-1850) * *Security Fix*: The server could be tricked into reading packets indefinitely if it received a packet larger than the maximum size of one packet. (Bug #50974, CVE-2010-1849) * *InnoDB Storage Engine*: *Note `InnoDB': innodb-storage-engine. page splitting could enter an infinite loop for compressed tables. (Bug #52964) * *InnoDB Storage Engine*: *Note `InnoDB': innodb-storage-engine. attempted to choose off-page storage without ensuring that there was an `off-page storage' flag in the record header. To correct this, in `DYNAMIC' and `COMPRESSED' formats, *Note `InnoDB': innodb-storage-engine. stores locally any non-*Note `BLOB': blob. columns having a maximum length not exceeding 256 bytes. This is because there is no room for the `external storage' flag when the maximum length is 255 bytes or less. This restriction trivially holds in `REDUNDANT' and `COMPACT' formats, because there *Note `InnoDB': innodb-storage-engine. always stores locally columns having a length up to `local_len' = 788 bytes. (Bug #52745) * MySQL incorrectly processed *Note `ALTER DATABASE `#mysql50#` UPGRADE DATA DIRECTORY NAME': alter-database. where was `.', `..', or a sequence starting with `./' or `../'. It used the server data directory (that contains other regular databases) as the database directory. (Bug #53804, CVE-2010-2008) * A syntactically invalid trigger could cause the server to crash when trying to list triggers. (Bug #50755) * Selecting from *Note `INFORMATION_SCHEMA.ROUTINES': routines-table. or `INFORMATION_SCHEMA.PARAMETERS' (http://dev.mysql.com/doc/refman/5.5/en/parameters-table.html) resulted in a memory leak. (Bug #48729) * *Note `EXPLAIN': explain. could cause a server crash for some queries with subqueries. (Bug #48419)  File: manual.info, Node: news-5-1-46, Next: news-5-1-45, Prev: news-5-1-46sp1, Up: news-5-1-x D.1.17 Changes in MySQL 5.1.46 (06 April 2010) ---------------------------------------------- *Important*: If you will be using the plugin version of *Note `InnoDB': innodb-storage-engine, we recommend that you use MySQL 5.1.48 or later instead of 5.1.46sp1. This is because 5.1.46 contains the first production-ready version and the later version has fixes for some of the bugs found during more widespread production use. *InnoDB Notes* * `InnoDB Plugin' has been upgraded to version 1.0.7. This version is considered of General Availability (GA) quality. InnoDB Plugin Change History (http://dev.mysql.com/doc/innodb-plugin/1.0/en/innodb-changes.html), may contain information in addition to those changes reported here. In this release, the `InnoDB Plugin' is included in source and binary distributions, except RHEL3, RHEL4, SuSE 9 (x86, x86_64, ia64), and generic Linux RPM packages. It also does not work for FreeBSD 6 and HP-UX or for Linux on generic ia64. *Functionality added or changed:* * There is a new system variable, `skip_name_resolve', that is set from the value of the `--skip-name-resolve' server option. This provides a way to determine at runtime whether the server uses name resolution for client connections. (Bug #37168) *Bugs fixed:* * *Performance*: *InnoDB Storage Engine*: The redo scan during `InnoDB' recovery used excessive CPU. The efficiency of this scan was improved for `InnoDB Plugin', significantly speeding up crash recovery. (Bug #49535, Bug #29847) * *Performance*: *InnoDB Storage Engine*: `InnoDB Plugin' page-freeing operations were made faster for compressed blocks, speeding up *Note `ALTER TABLE': alter-table, *Note `DROP TABLE': drop-table, and other operations on compressed tables that free compressed blocks. One symptom of the older behavior could be 100% CPU use during these operations. (Bug #35077) * *Performance*: While looking for the shortest index for a covering index scan, the optimizer did not consider the full row length for a clustered primary key, as in *Note `InnoDB': innodb-storage-engine. Secondary covering indexes will now be preferred, making full table scans less likely. (Bug #39653) See also Bug #55656. * *Security Fix*: Privilege checking for *Note `UNINSTALL PLUGIN': uninstall-plugin. was incorrect. (Bug #51770, CVE-2010-1621) * *Important Change*: When using fast *Note `ALTER TABLE': alter-table, different internal ordering of indexes in the MySQL optimizer and the *Note `InnoDB': innodb-storage-engine. storage engine could cause error messages about possibly mixed up `.frm' files and incorrect index use. (Bug #47622) * *InnoDB Storage Engine*: *Replication*: *Note `TRUNCATE TABLE': truncate-table. performed on a temporary table using the *Note `InnoDB': innodb-storage-engine. storage engine was logged even when using row-based mode. (Bug #51251) * *InnoDB Storage Engine*: *Replication*: Column length information generated by *Note `InnoDB': innodb-storage-engine. did not match that generated by *Note `MyISAM': myisam-storage-engine, which caused invalid metadata to be written to the binary log when trying to replicate *Note `BIT': numeric-types. columns. (Bug #49618) * *InnoDB Storage Engine*: For `InnoDB Plugin', bit fields were causing problems with concurrency on SMP systems because of word-packing issues. (Bug #52360) * *InnoDB Storage Engine*: Fixed a performance issue on Windows systems that affected the InnoDB Plugin, by turning off atomic instructions. (Bug #52102) * *InnoDB Storage Engine*: The AIX implementation of `readdir_r()' caused `InnoDB' errors. (Bug #50691) * *Partitioning*: Partition pruning on `RANGE' partitioned tables did not always work correctly; the last partition was not excluded if the range was beyond it (when not using `MAXVALUE'). Now the last partition is not included if the partitioning function value is not within the range. (Bug #51830) * *Partitioning*: The `insert_id' server system variable was not reset following an insert that failed on a partitioned *Note `MyISAM': myisam-storage-engine. table having an `AUTO_INCREMENT' column. (Bug #50392) * *Partitioning*: Foreign keys are not supported on partitioned tables. However, it was possible using an *Note `ALTER TABLE': alter-table. statement to set a foreign key on a partitioned table; it was also possible to partition a table with a single foreign key. (Bug #50104) * *Partitioning*: `GROUP BY' queries performed poorly for some partitioned tables. This was due to the block size not being set for partitioned tables, thus the keys per block was not correct, which could cause such queries to be optimized incorrectly. (Bug #48229) See also Bug #37252. * *Partitioning*: *Note `REPAIR TABLE': repair-table. failed for partitioned *Note `ARCHIVE': archive-storage-engine. tables. (Bug #46565) * *Replication*: When using temporary tables the binary log needs to insert a pseudo-thread ID for threads that are using temporary tables, each time a switch happens between two threads, both of which are using temporary tables. However, if a thread issued a failing statement before exit, its ID was not recorded in the binary log, and this in turn caused the ID for the next thread that tried to do something with a temporary table not to be logged as well. Subsequent replays of the binary log failed with the error `Table ... doesn't exist'. (Bug #51226) * *Replication*: If the master was using `sql_mode='TRADITIONAL'', duplicate key errors were not sent to the slave, which received `0' rather than the expected error code. This caused replication to fail even when such an error was expected. (Bug #51055) * *Replication*: When run with the `--database' option, *Note `mysqlbinlog': mysqlbinlog. printed *Note `ROLLBACK': commit. statements but did not print any corresponding *Note `SAVEPOINT': savepoint. statements. (Bug #50407) * *Replication*: When a *Note `CREATE EVENT': create-event. statement was followed by an additional statement and the statements were executed together as a single statement, the *Note `CREATE EVENT': create-event. statement was padded with `garbage' characters when written to the binary log, which led to a syntax error when trying to read back from the log. (Bug #50095) * *Replication*: The value of `Slave_IO_running' in the output of *Note `SHOW SLAVE STATUS': show-slave-status. did not distinguish between all 3 possible states of the slave I/O thread (not running; running but not connected; connected). Now the value `Connecting' (rather than `No') is shown when the slave I/O thread is running but the slave is not connected to a replication master. The server system variable `Slave_running' also reflects this change, and is now consistent with what is shown for `Slave_IO_running'. (Bug #30703, Bug #41613, Bug #51089) * *Note `EXPLAIN EXTENDED': explain. crashed trying to resolve references to freed temporary table columns for `GROUP_CONCAT()' `ORDER BY' arguments. (Bug #52397) * The optimizer could attempt to evaluate the `WHERE' clause before any rows had been read, resulting in a server crash. (Bug #52177) * For LDML-defined collations, some data structures were not initialized properly to enable `UPPER()' and `LOWER()' to work correctly. (Bug #51976) * On Windows, `LOAD_FILE()' could cause a crash for some pathnames. (Bug #51893) * Invalid memory reads occurred for *Note `HANDLER ... READ NEXT': handler. after a failed *Note `HANDLER ... READ FIRST': handler. (Bug #51877) * After *Note `TRUNCATE TABLE': truncate-table. of a *Note `MyISAM': myisam-storage-engine. table, subsequent queries could crash the server if `myisam_use_mmap' was enabled. (Bug #51868) * If `myisam_sort_buffer_size' was set to a small value, table repair for *Note `MyISAM': myisam-storage-engine. tables with `FULLTEXT' indexes could crash the server. (Bug #51866) * In *Note `LOAD DATA INFILE': load-data, using a `SET' clause to set a column equal to itself caused a server crash. (Bug #51850) * A problem with equality propagation optimization for prepared statements and stored procedures caused a server crash upon re-execution of the prepared statement or stored procedure. (Bug #51650) See also Bug #8115, Bug #8849. * The optimizer performed an incorrect join type when `COALESCE()' appeared within an `IN()' operation. (Bug #51598) * The server crashed when the optimizer attempted to determine constant tables but a table storage engine did not support exact record count. (Bug #51494) * A unique index on a column prefix could not be upgraded to a primary index even if there was no primary index already defined. (Bug #51378) * The server could crash populating the *Note `INFORMATION_SCHEMA.PROCESSLIST': processlist-table. table due to lack of mutex protection. (Bug #51377) * Use of *Note `HANDLER': handler. statements with tables that had spatial indexes caused a server crash. (Bug #51357) * With an XA transaction active, *Note `SET autocommit = 1': set-option. could cause side effects such as memory corruption or a server crash. (Bug #51342) * Following a bulk insert into a *Note `MyISAM': myisam-storage-engine. table, if *Note `MyISAM': myisam-storage-engine. failed to build indexes using repair by sort, data file corruption could occur. (Bug #51307) * *Note `CHECKSUM TABLE': checksum-table. could compute the checksum for `BIT' columns incorrectly. (Bug #51304) * A `HAVING' clause on a joined table in some cases failed to eliminate rows which should have been excluded from the result set. (Bug #51242) * The type inference used for view columns caused some columns in views to be handled as the wrong type, as compared to the same columns in base tables. *Note `DATE': datetime. columns in base tables were treated as *Note `TIME': time. columns in views, and base table *Note `TIME': time. columns as view *Note `DATETIME': datetime. columns. (Bug #50918) * The *Note `YEAR': year. values `2000' and `0000' could be treated as equal. (Bug #49910) * Performing a single in-place *Note `ALTER TABLE': alter-table. containing `ADD INDEX' and `DROP INDEX' options that used the same index name could result in a corrupt table definition file. Now such *Note `ALTER TABLE': alter-table. statements are no longer performed in place. (Bug #49838) * *Note `mysql_upgrade': mysql-upgrade. did not detect when *Note `CSV': csv-storage-engine. log tables incorrectly contained columns that could be `NULL'. Now these columns are altered to be `NOT NULL'. (Bug #49823) * *Note `InnoDB': innodb-storage-engine. would return an error when inserting a negative value into an auto-increment column. (Bug #49497) * *Note `InnoDB': innodb-storage-engine. did not reset table `AUTO_INCREMENT' values to the last used values after a server restart. (Bug #49032) * If a stored function contained a *Note `RETURN': return. statement with an `ENUM' value in the `ucs2' character set, *Note `SHOW CREATE FUNCTION': show-create-function. and `SELECT DTD_IDENTIFIER FROM INFORMATION_SCHEMA.ROUTINES' returned incorrect values. (Bug #48766) * A trigger could change the behavior of assigning `NULL' to a `NOT NULL' column. (Bug #48525) * The server crashed when it could not determine the best execution plan for queries involving outer joins with nondeterministic `ON' clauses such as the ones containing the `RAND()' function, a user-defined function, or a `NOT DETERMINISTIC' stored function. (Bug #48483) * The *Note `MERGE': merge-storage-engine. engine failed to open a child table from a different database if the child table or database name contained characters that were the subject of table name to filename encoding. Further, the *Note `MERGE': merge-storage-engine. engine did not properly open a child table from the same database if the child table name contained characters such as '/', '#'. (Bug #48265) * A query that read from a derived table (of the form `SELECT ... FROM (SELECT ...)') produced incorrect results when the following conditions were present: * The table subquery contained a derived query (`(SELECT ... ) AS COLUMN'). * The derived query could potentially produce zero rows or a single `NULL' (that is, no rows matched, or the query used an aggregate function such as `SUM()' running over zero rows). * The table subquery joined at least two tables. * The join condition involved an index. (Bug #47904) * The optimization to read `MIN()' or `MAX()' values from an index did not properly handle comparisons with `NULL' values. This could produce incorrect results for `MIN()' or `MAX()'when the `WHERE' clause tested a `NOT NULL' column for `NULL'. (Bug #47762) * Killing a query during the optimization phase of a subquery could cause a server crash. (Bug #47761) * The query shown by *Note `EXPLAIN EXTENDED': explain. plus *Note `SHOW WARNINGS': show-warnings. could produce results different from the original query. (Bug #47669) * Renaming a column of an *Note `InnoDB': innodb-storage-engine. table caused the server to go out of sync with the *Note `InnoDB': innodb-storage-engine. data dictionary. To avoid this issue, renaming a column uses the older technique of copying all the table data rather than updating the table in-place. (Bug #47621) * *Note `MyISAM': myisam-storage-engine. could write uninitialized data to new index pages. Now zeros are written to unused bytes in the pages. (Bug #47598) * Setting `myisam_repair_threads' larger than 1 could result in the cardinality for all indexes of a *Note `MyISAM': myisam-storage-engine. table being set to 1 after parallel index repair. (Bug #47444) * In debug builds, if the listed columns in the view definition of the table used in an *Note `INSERT ... SELECT': insert. statement mismatched, an assertion was raised in the query cache invalidation code following the failing statement. (Bug #46615) * For a query that selected from a view and used an alias for the view, the metadata used the alias name rather than the view name in the `MYSQL_FIELD.table' member. (Bug #41788) * *Note `mysql_upgrade': mysql-upgrade. did not create temporary files properly. (Bug #41057) * It was possible for *Note `DROP TABLE': drop-table. of one *Note `MyISAM': myisam-storage-engine. table to remove the data and index files of a different *Note `MyISAM': myisam-storage-engine. table. (Bug #40980) * If the arguments to a `CONCAT()' call included a local routine variable, selecting the return value into a user variable could produce an incorrect result. (Bug #40625) * *Note `SHOW CREATE VIEW': show-create-view. returned invalid SQL if the definition contained a *Note `SELECT': select. `'STRING'' statement where the STRING was longer than the maximum length of a column name, due to the fact that this text was also used as an alias (in the `AS' clause). Because not all names retrieved from arbitrary *Note `SELECT': select. statements can be used as view column names due to length and format restrictions, the server now checks the conformity of automatically generated column names and rewrites according to a predefined format any names that are not acceptable as view column names before storing the final view definition on disk. In such cases, the name is now rewritten as `Name_exp_POS', where POS is the position of the column. To avoid this conversion scheme, define explicit, valid names for view columns using the COLUMN_LIST clause of the *Note `CREATE VIEW': create-view. statement. As part of this fix, aliases are now generated only for top-level statements. (Bug #40277) * *Note `mysqlbinlog': mysqlbinlog. option-processing code had a memory leak. (Bug #38468) * The test for `readline' during configuration failed when trying to build MySQL in a directory other than the source tree root. (Bug #35250) * A query on a `FEDERATED' table in which the data was ordered by a `TEXT' column returned incorrect results. For example, a query such as the following would result in incorrect results if column `column1' was a `TEXT' column: SELECT * FROM table1 ORDER BY column1; (Bug #32426)  File: manual.info, Node: news-5-1-45, Next: news-5-1-44, Prev: news-5-1-46, Up: news-5-1-x D.1.18 Changes in MySQL 5.1.45 (01 March 2010) ---------------------------------------------- *InnoDB Notes* * This release includes `InnoDB Plugin' 1.0.6. This version is considered of Release Candidate (RC) quality. In this release, the `InnoDB Plugin' is included in source and binary distributions, except RHEL3, RHEL4, SuSE 9 (x86, x86_64, ia64), and generic Linux RPM packages. It also does not work for FreeBSD 6 and HP-UX or for Linux on generic ia64. *Functionality added or changed:* * `mysqltest' has a new `--max-connections' option to set a higher number of maximum permitted server connections than the default 128. This option can also be passed using `mysql-test-run.pl'. (Bug #51135) * `mysql-test-run.pl' has a new `--portbase' option and a corresponding `MTR_PORT_BASE' environment variable for setting the port range, as an alternative to the existing `--build-thread' option. (Bug #50182) * `mysql-test-run.pl' has a new `--gprof' option that runs the server through the `gprof' profiler, much the same way the currently supported `--gcov' option runs it through `gcov'. (Bug #49345) * `mysqltest' has a new `lowercase_result' command that converts the output of the next statement to lowercase. This is useful for test cases where the lettercase may vary between platforms. (Bug #48863) * `mysqltest' has a new `remove_files_wildcard' command that removes files matching a pattern from a directory. (Bug #39774) *Bugs fixed:* * *InnoDB Storage Engine*: `SHOW INNODB STATUS' could display incorrect information about deadlocks, when the deadlock detection routine stops early (to avoid excessive CPU usage). (Bug #49001) * *Partitioning*: Attempting to drop a partitioned table from one connection while waiting for the completion of an *Note `ALTER TABLE': alter-table. that had been issued from a different connection, and that changed the storage engine used by the table, could cause the server to crash. (Bug #42438) * *Replication*: Adding an index to a table on the master caused the slave to stop logging slow queries to the slow query log. (Bug #50620) * *Replication*: Queries written to the slow query log on the master were not written to the slow query log on the slave. (Bug #23300) See also Bug #48632. * *Note `mysqld_multi': mysqld-multi. failed due to a syntax error in the script. (Bug #51468) * Referring to a subquery result in a `HAVING' clause could produce incorrect results. (Bug #50995) * Use of `filesort' plus the join cache normally is preferred to a full index scan. But it was used even if the index is clustered, in which case, the clustered index scan can be faster. (Bug #50843) * For debug builds, *Note `SHOW BINARY LOGS': show-binary-logs. caused an assertion to be raised if binary logging was not enabled. (Bug #50780) * The server did not recognize that the stored procedure cache became invalid if a view was created or modified within a procedure, resulting in a crash. (Bug #50624) * Incorrect handling of *Note `BIT': numeric-types. columns in temporary tables could lead to spurious duplicate-key errors. (Bug #50591) * The second or subsequent invocation of a stored procedure containing *Note `DROP TRIGGER': drop-trigger. could cause a server crash. (Bug #50423) * Full-text queries that used the truncation operator (`*') could enter an infinite loop. (Bug #50351) * For debug builds, an assertion was incorrectly raised in the optimizer when matching `ORDER BY' expressions. (Bug #50335) * Queries optimized with `GROUP_MIN_MAX' did not clean up `KEYREAD' optimizations properly, causing subsequent queries to return incomplete rows. (Bug #49902) * For dynamic format *Note `MyISAM': myisam-storage-engine. tables containing *Note `LONGTEXT': blob. columns, a bulk *Note `INSERT ... ON DUPLICATE KEY UPDATE': insert. or bulk *Note `REPLACE': replace. could cause corruption. (Bug #49628) * For debug builds, with `sql_safe_updates' enabled, a multiple-table *Note `UPDATE': update. with the `IGNORE' modifier could raise an assertion. (Bug #49534) * *Note `EXPLAIN EXTENDED': explain. crashed trying to print column names for a subquery in the `FROM' clause when the table had gone out of scope. (Bug #49487) * For *Note `InnoDB': innodb-storage-engine. tables, the test for using an index for `ORDER BY' sorting did not distinguish between primary keys and secondary indexes and expected primary key values to be concatenated to index values the way they are to secondary key values. (Bug #49324) * `mysqltest' no longer lets you execute an SQL statement on a connection after doing a `send' command, unless you do a `reap' first. This was previously accepted but could produce unpredictable results. (Bug #49269) * For debug builds on Windows, warnings about incorrect use of debugging directives were written to the error log. The directives were rewritten to eliminate these messages. (Bug #49025) * An ARZ file missing from the database directory caused the server to crash. (Bug #48757) * Running *Note `SHOW CREATE TABLE': show-create-table. on a view `v1' that contained a function which accessed another view `v2' could trigger a infinite loop if the view (`v2') referenced within the function caused a warning to be raised while being opened. (Bug #48449) * Invalid memory reads could occur following a query that referenced a *Note `MyISAM': myisam-storage-engine. tale multiple times with a write lock. (Bug #48438) * For debug builds, creating a view containing a row constructor caused an assertion to be raised. (Bug #48294) * Slow *Note `CALL': call. statements were not always logged to the slow query log because execution time for multiple-statement stored procedures was assessed incorrectly. (Bug #47905) * For debug builds, killing a *Note `SELECT': select. retrieving from a view that was processing a function caused an assertion to be raised. (Bug #47736) * Failure to open a view with a nonexistent `DEFINER' was improperly handled and the server would crash later attempting to lock the view. (Bug #47734) * If *Note `EXPLAIN': explain. encountered an error in the query, a memory leak occurred. (Bug #45989) * Grouping by a subquery in a query with a `DISTINCT' aggregate function led to incorrect and unordered grouping values. (Bug #45640) * Propagation of a large unsigned numeric constant in `WHERE' expressions could lead to incorrect results. This also affected *Note `EXPLAIN EXTENDED': explain, which printed incorrect numeric constants in such transformed `WHERE' expressions. (Bug #45360) * Valgrind warnings about uninitialized variables in optimizer code were corrected. (Bug #45195) * `flush_cache_records()' did not correctly check for errors that should cause statement execution to stop, leading to a server crash. (Bug #39022) * *Note `InnoDB': innodb-storage-engine. logged an error repeatedly trying to load a page into the buffer pool, filling the error log and using excessive disk space. Now the number of attempts is limited to 100, after which the operation aborts with a message. (Bug #38901) * When building MySQL when using a different target directory (for example using the `VPATH' environment variable), the build of the embedded `readline' component would fail. (Bug #35250) * *Note `INSERT INTO ... VALUES(DEFAULT)': insert. failed to insert the correct value for *Note `ENUM': enum. columns. For *Note `MyISAM': myisam-storage-engine. tables, an empty value was inserted. For *Note `CSV': csv-storage-engine. tables, the table became corrupt. (Bug #33717)  File: manual.info, Node: news-5-1-44, Next: news-5-1-43sp1, Prev: news-5-1-45, Up: news-5-1-x D.1.19 Changes in MySQL 5.1.44 (04 February 2010) ------------------------------------------------- *InnoDB Notes* * This release includes `InnoDB Plugin' 1.0.6. This version is considered of Release Candidate (RC) quality. In this release, the `InnoDB Plugin' is included in source and binary distributions, except RHEL3, RHEL4, SuSE 9 (x86, x86_64, ia64), and generic Linux RPM packages. It also does not work for FreeBSD 6 and HP-UX or for Linux on generic ia64. *Functionality added or changed:* * *Replication*: Introduced the `binlog_direct_non_transactional_updates' system variable. Enabling this variable causes updates using the statement-based logging format to tables using nontransactional engines to be written directly to the binary log, rather than to the transaction cache. Before enabling this variable, be certain that you have no dependencies between transactional and nontransactional tables. A statement that both selects from an *Note `InnoDB': innodb-storage-engine. table and inserts into a *Note `MyISAM': myisam-storage-engine. table is an example of such a dependency. For more information, see *Note replication-options-binary-log::. (Bug #46364) See also Bug #28976, Bug #40116. *Bugs fixed:* * *Performance*: The method for comparing `INFORMATION_SCHEMA' names and database names was nonoptimal and an improvement was made: When the database name length is already known, a length check is made first and content comparison skipped if the lengths are unequal. (Bug #49501) * *Performance*: The `MD5()' and `SHA1()' functions had excessive overhead for short strings. (Bug #49491) * *Partitioning*: *InnoDB Storage Engine*: When an *Note `ALTER TABLE ... REORGANIZE PARTITION': alter-table. statement on an `InnoDB' table failed due to `innodb_lock_wait_timeout' expiring while waiting for a lock, `InnoDB' did not clean up any temporary files or tables which it had created. Attempting to reissue the *Note `ALTER TABLE': alter-table. statement following the timeout could lead to storage engine errors, or possibly a crash of the server. (Bug #47343) * *InnoDB Storage Engine*: Creating or dropping a table with 1023 transactions active caused an assertion failure. (Bug #49238) * *InnoDB Storage Engine*: If `innodb_force_recovery' was set to 4 or higher, the server could crash when opening an *Note `InnoDB': innodb-storage-engine. table containing an auto-increment column. MySQL versions 5.1.31 and later were affected. (Bug #46193) * *Replication*: In some cases, inserting into a table with many columns could cause the binary log to become corrupted. (Bug #50018) See also Bug #42749. * *Replication*: When using row-based replication, setting a *Note `BIT': numeric-types. or *Note `CHAR': char. column of a *Note `MyISAM': myisam-storage-engine. table to `NULL', then trying to delete from the table, caused the slave to fail with the error `Can't find record in TABLE'. (Bug #49481, Bug #49482) * *Replication*: When logging in row-based mode, DDL statements are actually logged as statements; however, statements that affected temporary tables and followed DDL statements failed to reset the binary log format to `ROW', with the result that these statements were logged using the statement-based format. Now the state of `binlog_format' is restored after a DDL statement has been written to the binary log. (Bug #49132) * *Replication*: When using row-based logging, the statement *Note `CREATE TABLE t IF NOT EXIST ... SELECT': create-table. was logged as *Note `CREATE TEMPORARY TABLE t IF NOT EXIST ... SELECT': create-table. when `t' already existed as a temporary table. This was caused by the fact that the temporary table was opened and the results of the *Note `SELECT': select. were inserted into it when a temporary table existed and had the same name. Now, when this statement is executed, `t' is created as a base table, the results of the *Note `SELECT': select. are inserted into it--even if there already exists a temporary table having the same name--and the statement is logged correctly. (Bug #47418) See also Bug #47442. * *Replication*: Due to a change in the size of event representations in the binary log, when replicating from a MySQL 4.1 master to a slave running MySQL 5.0.60 or later, the *Note `START SLAVE UNTIL': start-slave. statement did not function correctly, stopping at the wrong position in the log. Now the slave detects that the master is using the older version of the binary log format, and corrects for the difference in event size, so that the slave stops in the correct position. (Bug #47142) * The SSL certificates in the test suite were about to expire. They have been updated with expiration dates in the year 2015. (Bug #50642) * The `printstack' function does not exist on Solaris 8 or earlier, which would lead to a compilation failure. (Bug #50409) * A user could see tables in *Note `INFORMATION_SCHEMA.TABLES': tables-table. without appropriate privileges for them. (Bug #50276) * Debug output for join structures was garbled. (Bug #50271) * The `filesort' sorting method applied to a *Note `CHAR(0)': char. column could lead to a server crash. (Bug #49897) * `sql_buffer_result' had an effect on non-*Note `SELECT': select. statements, contrary to the documentation. (Bug #49552) * In some cases a subquery need not be evaluated because it returns only aggregate values that can be calculated from table metadata. This sometimes was not handled by the enclosing subquery, resulting in a server crash. (Bug #49512) * Mixing full-text searches and row expressions caused a crash. (Bug #49445) * `mysql-test-run.pl' now recognizes the `MTR_TESTCASE_TIMEOUT', `MTR_SUITE_TIMEOUT', `MTR_SHUTDOWN_TIMEOUT', and `MTR_START_TIMEOUT' environment variables. If they are set, their values are used to set the `--testcase-timeout', `--suite-timeout', `--shutdown-timeout', and `--start-timeout' options, respectively. (Bug #49210) * The optimizer could continue to execute a query after a storage engine reported an error, leading to a server crash. (Bug #46175)  File: manual.info, Node: news-5-1-43sp1, Next: news-5-1-43, Prev: news-5-1-44, Up: news-5-1-x D.1.20 Release Notes for MySQL Enterprise 5.1.43sp1 [QSP] (25 March 2010) ------------------------------------------------------------------------- This is a _Service Pack_ release of the MySQL Enterprise Server 5.1. *Bugs fixed:* * *Partitioning*: *InnoDB Storage Engine*: When an *Note `ALTER TABLE ... REORGANIZE PARTITION': alter-table. statement on an `InnoDB' table failed due to `innodb_lock_wait_timeout' expiring while waiting for a lock, `InnoDB' did not clean up any temporary files or tables which it had created. Attempting to reissue the *Note `ALTER TABLE': alter-table. statement following the timeout could lead to storage engine errors, or possibly a crash of the server. (Bug #47343) * *InnoDB Storage Engine*: If `innodb_force_recovery' was set to 4 or higher, the server could crash when opening an *Note `InnoDB': innodb-storage-engine. table containing an auto-increment column. MySQL versions 5.1.31 and later were affected. (Bug #46193) * Referring to a subquery result in a `HAVING' clause could produce incorrect results. (Bug #50995) * The `filesort' sorting method applied to a *Note `CHAR(0)': char. column could lead to a server crash. (Bug #49897) * `sql_buffer_result' had an effect on non-*Note `SELECT': select. statements, contrary to the documentation. (Bug #49552) * In some cases a subquery need not be evaluated because it returns only aggregate values that can be calculated from table metadata. This sometimes was not handled by the enclosing subquery, resulting in a server crash. (Bug #49512) * `flush_cache_records()' did not correctly check for errors that should cause statement execution to stop, leading to a server crash. (Bug #39022)  File: manual.info, Node: news-5-1-43, Next: news-5-1-42, Prev: news-5-1-43sp1, Up: news-5-1-x D.1.21 Changes in MySQL 5.1.43 (15 January 2010) ------------------------------------------------ *InnoDB Notes* * This release includes `InnoDB Plugin' 1.0.6. This version is considered of Release Candidate (RC) quality. In this release, the `InnoDB Plugin' is included in source and binary distributions, except RHEL3, RHEL4, SuSE 9 (x86, x86_64, ia64), and generic Linux RPM packages. It also does not work for FreeBSD 6 and HP-UX or for Linux on S/390, PowerPC, and generic ia64. *Functionality added or changed:* * *Partitioning*: The `UNIX_TIMESTAMP()' function is now supported in partitioning expressions using *Note `TIMESTAMP': datetime. columns. For example, it now possible to create a partitioned table such as this one: CREATE TABLE t (c TIMESTAMP) PARTITION BY RANGE ( UNIX_TIMESTAMP(c) ) ( PARTITION p0 VALUES LESS THAN (631148400), PARTITION p1 VALUES LESS THAN (946681200), PARTITION p2 VALUES LESS THAN (MAXVALUE) ); All other expressions involving *Note `TIMESTAMP': datetime. values are now rejected with an error when attempting to create a new partitioned table or to alter an existing partitioned table. When accessing an existing partitioned table having a timezone-dependent partitioning function (where the table was using a previous version of MySQL), a warning rather than an error is issued. In such cases, you should fix the table. One way of doing this is to alter the table's partitioning expression so that it uses `UNIX_TIMESTAMP()'. (Bug #42849) *Bugs fixed:* * *Performance*: *Partitioning*: When used on partitioned tables, the `records_in_range' handler call checked more partitions than necessary. The fix for this issue reduces the number of unpruned partitions checked for statistics in partition range checking, which has resulted in some partition operations being performed up to 2-10 times faster than before this change was made, when testing with tables having 1024 partitions. (Bug #48846) See also Bug #37252, Bug #47261. * *Security Fix*: For servers built with yaSSL, a preauthorization buffer overflow could cause memory corruption or a server crash. We thank Evgeny Legerov from Intevydis for providing us with a proof-of-concept script that permitted us to reproduce this bug. (Bug #50227, CVE-2009-4484) * *Important Change*: *Replication*: The `RAND()' function is now marked as unsafe for statement-based replication. Using this function now generates a warning when `binlog_format=STATEMENT' and causes the format to switch to row-based logging when `binlog_format=MIXED'. This change is being introduced because, when `RAND()' was logged in statement mode, the seed was also written to the binary log, so the replication slave generated the same sequence of random numbers as was generated on the master. While this could make replication work in some cases, the order of affected rows was still not guaranteed when this function was used in statements that could update multiple rows, such as *Note `UPDATE': update. or *Note `INSERT ... SELECT': insert-select.; if the master and the slave retrieved rows in different order, they began to diverge. (Bug #49222) * *InnoDB Storage Engine*: When compiling on Windows, an error in the `CMake' definitions for `InnoDB' would cause the engine to be built incorrectly. (Bug #49502) * *InnoDB Storage Engine*: The `InnoDB Monitor' could fail to print diagnostic information after a long lock wait. (Bug #47814) * *InnoDB Storage Engine*: Crash recovery did not work for *Note `InnoDB': innodb-storage-engine. temporary tables. (Bug #41609) * *Partitioning*: A query that searched on a `ucs2' column failed if the table was partitioned. (Bug #48737) * *Replication*: A *Note `LOAD DATA INFILE': load-data. statement that loaded data into a table having a column name that had to be escaped (such as ``key` INT') caused replication to fail when logging in mixed or statement mode. In such cases, the master wrote the *Note `LOAD DATA': load-data. event into the binary log without escaping the column names. (Bug #49479) See also Bug #47927. * *Replication*: Spatial data types caused row-based replication to crash. (Bug #48776) * *Replication*: A flaw in the implementation of the purging of binary logs could result in orphaned files being left behind in the following circumstances: * If the server failed or was killed while purging binary logs. If the server failed or was killed after creating of a new binary log when the new log file was opened for the first time. In addition, if the slave was not connected during the purge operation, it was possible for a log file that was in use to be removed; this could lead data loss and possible inconsistencies between the master and slave. (Bug #45292) * *Replication*: When using the `STATEMENT' or `MIXED' logging format, the statements *Note `LOAD DATA CONCURRENT LOCAL INFILE': load-data. and *Note `LOAD DATA CONCURRENT INFILE': load-data. were logged as *Note `LOAD DATA LOCAL INFILE': load-data. and *Note `LOAD DATA LOCAL INFILE': load-data, respectively (in other words, the `CONCURRENT' keyword was omitted). As a result, when using replication with either of these logging modes, queries on the slaves were blocked by the replication SQL thread while trying to execute the affected statements. (Bug #34628) * *Replication*: Manually removing entries from the binary log index file on a replication master could cause the server to repeatedly send the same binary log file to slaves. (Bug #28421) * *Cluster Replication*: When `expire_logs_days' was set, the thread performing the purge of the log files could deadlock, causing all binary log operations to stop. (Bug #49536) * Within a stored routine, selecting the result of `CONCAT_WS()' with a routine parameter argument into a user variable could return incorrect results. (Bug #50096) * The *Note `IBMDB2I': se-db2. storage engine was missing from the i5os 64-bit distribution of MySQL 5.1.42. It is now included again. (Bug #50059) * *Note `EXPLAIN EXTENDED UNION ... ORDER BY': explain. caused a crash when the `ORDER BY' referred to a nonconstant or full-text function or a subquery. (Bug #49734) * The `push_warning_printf()' function was being called with an invalid error level `MYSQL_ERROR::WARN_LEVEL_ERROR', causing an assertion failure. To fix the problem, `MYSQL_ERROR::WARN_LEVEL_ERROR' has been replaced by `MYSQL_ERROR::WARN_LEVEL_WARN'. (Bug #49638) * Some prepared statements could raise an assertion when re-executed. (Bug #49570) * A Valgrind error in `make_cond_for_table_from_pred()' was corrected. Thanks to Sergey Petrunya for the patch to fix this bug. (Bug #49506) * Valgrind warnings for *Note `CHECKSUM TABLE': checksum-table. were corrected. (Bug #49465) * Specifying an index algorithm (such as `BTREE') for `SPATIAL' or `FULLTEXT' indexes caused a server crash. These index types do not support algorithm specification, and it is not longer permitted to do so. (Bug #49250) * The optimizer sometimes incorrectly handled conditions of the form `WHERE COL_NAME='CONST1' AND COL_NAME='CONST2''. (Bug #49199) * Execution of `DECODE()' and `ENCODE()' could be inefficient because multiple executions within a single statement reinitialized the random generator multiple times even with constant parameters. (Bug #49141) * MySQL 5.1 does not support 2-byte collation numbers, but did not check the number and crashed for out-of-range values. (Bug #49134) * With binary logging enabled, *Note `REVOKE ... ON {PROCEDURE|FUNCTION} FROM ...': revoke. could cause a crash. (Bug #49119) * The `LIKE' operator did not work correctly when using an index for a `ucs2' column. (Bug #49028) * `check_key_in_view()' was missing a `DBUG_RETURN' in one code branch, causing a crash in debug builds. (Bug #48995) * Several `strmake()' calls had an incorrect length argument (too large by one). (Bug #48983) * On Fedora 12, `strmov()' did not guarantee correct operation for overlapping source and destination buffer. Calls were fixed to use an overlap-safe version instead. (Bug #48866) * Incomplete reset of internal `TABLE' structures could cause a crash with `eq_ref' table access in subqueries. (Bug #48709) * Re-execution of a prepared statement could cause a server crash. (Bug #48508) * The error message for `ER_UPDATE_INFO' was subject to buffer overflow or truncation. (Bug #48500) * *Note `SHOW BINLOG EVENTS': show-binlog-events. could fail with a error: `Wrong offset or I/O error'. (Bug #48357) * Valgrind warnings related to binary logging of *Note `LOAD DATA INFILE': load-data. statements were corrected. (Bug #48340) * An aliasing violation in the C API could lead to a crash. (Bug #48284) * With one thread waiting for a lock on a table, if another thread dropped the table and created a new table with the same name and structure, the first thread would not notice that the table had been re-created and would try to used cached metadata that belonged to the old table but had been freed. (Bug #48157) * Queries containing `GROUP BY ... WITH ROLLUP' that did not use indexes could return incorrect results. (Bug #47650) * If an invocation of a stored procedure failed in the table-open stage, subsequent invocations that did not fail in that stage could cause a crash. (Bug #47649) * On Solaris, no stack trace was printed to the error log after a crash. (Bug #47391) * A crash occurred when a user variable that was assigned to a subquery result was used as a result field in a *Note `SELECT': select. statement with aggregate functions. (Bug #47371) * The first execution of *Note `STOP SLAVE UNTIL': stop-slave. stopped too early. (Bug #47210) * When the *Note `mysql': mysql. client was invoked with the `--vertical' option, it ignored the `--skip-column-names' option. (Bug #47147) * It was possible for `init_available_charsets()' not to initialize correctly. (Bug #45058) * For a *Note `VARCHAR(N)': char. column, `ORDER BY BINARY(COL_NAME)' sorted using only the first N bytes of the column, even though column values could be longer than N bytes if they contained multibyte characters. (Bug #44131) * Comparison with `NULL' values sometimes did not produce a correct result. (Bug #42760) * The *Note `mysql_upgrade': mysql-upgrade. command would create three additional fields to the `mysql.proc' table (`character_set_client', `collation_connection', and `db_collation'), but did not populate the fields with correct values. This would lead to error messages reported during stored procedure execution. (Bug #41569) * When compressed *Note `MyISAM': myisam-storage-engine. files were opened, they were always memory mapped, sometimes causing memory-swapping problems. To deal with this, a new system variable, `myisam_mmap_size', was added to limit the amount of memory used for memory mapping of *Note `MyISAM': myisam-storage-engine. files. (Bug #37408) * A race condition on the privilege hash tables permitted one thread to try to delete elements that had already been deleted by another thread. A consequence was that *Note `SET PASSWORD': set-option. or *Note `FLUSH PRIVILEGES': flush. could cause a crash. (Bug #35589, Bug #35591) * *Note `ALTER TABLE': alter-table. with both `DROP COLUMN' and `ADD COLUMN' clauses could crash or lock up the server. (Bug #31145)  File: manual.info, Node: news-5-1-42, Next: news-5-1-41, Prev: news-5-1-43, Up: news-5-1-x D.1.22 Changes in MySQL 5.1.42 (15 December 2009) ------------------------------------------------- *InnoDB Notes* * `InnoDB Plugin' has been upgraded to version 1.0.6. This version is considered of Release Candidate (RC) quality. InnoDB Plugin Change History (http://dev.mysql.com/doc/innodb-plugin/1.0/en/innodb-changes.html), may contain information in addition to those changes reported here. In this release, the `InnoDB Plugin' is included in source and binary distributions, except RHEL3, RHEL4, SuSE 9 (x86, x86_64, ia64), and generic Linux RPM packages. It also does not work for FreeBSD 6 and HP-UX or for Linux on S/390, PowerPC, and generic ia64. *Release availability:* * MySQL Server 5.1 is available on the following new platforms starting with the 5.1.42 release: * Mac OS X 10.6 x86/x64 * HP-UX 11.31 IA64 * SLES 11 x86/x64 *Bugs fixed:* * *Performance*: When the query cache is fragmented, the size of the free block lists in the memory bins grows, which causes query cache invalidation to become slow. There is now a 50ms timeout for a *Note `SELECT': select. statement waiting for the query cache lock. If the timeout expires, the statement executes without using the query cache. (Bug #39253) See also Bug #21074. * *Important Change*: *Replication*: The following functions have been marked unsafe for statement-based replication: * `GET_LOCK()' * `IS_FREE_LOCK()' * `IS_USED_LOCK()' * `MASTER_POS_WAIT()' * `RELEASE_LOCK()' * `SLEEP()' * `SYSDATE()' * `VERSION()' None of the functions just listed are guaranteed to replicate correctly when using the statement-based format, because they can produce different results on the master and the slave. The use of any of these functions while `binlog_format' is set to `STATEMENT' is logged with the warning, `Statement is not safe to log in statement format'. When `binlog_format' is set to `MIXED', the binary logging format is automatically switched to the row-based format whenever one of these functions is used. (Bug #47995) * *Important Change*: After a binary upgrade to MySQL 5.1 from a MySQL 5.0 installation that contains *Note `ARCHIVE': archive-storage-engine. tables: * Before MySQL 5.1.42, accessing those tables will cause the server to crash, even if you have run *Note `mysql_upgrade': mysql-upgrade. or *Note `CHECK TABLE ... FOR UPGRADE': check-table. * As of MySQL 5.1.42, the server will not open 5.0 *Note `ARCHIVE': archive-storage-engine. tables at all. In either case, the solution is to use *Note `mysqldump': mysqldump. to dump all 5.0 *Note `ARCHIVE': archive-storage-engine. tables before upgrading, and reload them into MySQL 5.1 after upgrading. The same problem occurs for binary downgrades from MySQL 5.1 to 5.0. (Bug #47012) * *Partitioning*: In some cases, it was not possible to add a new column to a table that had subpartitions. (Bug #48276) * *Partitioning*: *Note `SELECT COUNT(*)': select. from a partitioned table failed when using the `ONLY_FULL_GROUP_BY' SQL mode. (Bug #46923) This regression was introduced by Bug #45807. * *Partitioning*: `SUBPARTITION BY KEY' failed with `DEFAULT CHARSET=utf8'. (Bug #45904) * *Replication*: When using row-based logging, *Note `TRUNCATE TABLE': truncate-table. was written to the binary log even if the affected table was temporary, causing replication to fail. (Bug #48350) * *Replication*: Replicating *Note `TEXT': blob. or *Note `VARCHAR': char. columns declared as `NULL' on the master but `NOT NULL' on the slave caused the slave to crash. (Bug #43789) See also Bug #38850, Bug #43783, Bug #43785, Bug #47741, Bug #48091. * *Replication*: When using row-based format, replication failed with the error `Could not execute Write_rows event on table ...; Field '...' doesn't have a default value' when an *Note `INSERT': insert. was made on the master without specifying a value for a column having no default, even if strict server SQL mode was not in use and the statement would otherwise have succeeded on the master. Now the SQL mode is checked, and the statement is replicated unless strict mode is in effect. For more information, see *Note server-sql-mode::. (Bug #38173) See also Bug #38262, Bug #43992. * The result of comparison between nullable *Note `BIGINT': numeric-types. and *Note `INT': numeric-types. columns was inconsistent. (Bug #49517) * Incorrect cache initialization prevented storage of converted constant values and could produce incorrect comparison results. (Bug #49489) * Comparisons involving *Note `YEAR': year. values could produce incorrect results. (Bug #49480) See also Bug #43668. * If a query involving a table was terminated with *Note `KILL': kill, a subsequent *Note `SHOW CREATE TABLE': show-create-table. for that table caused a server crash. (Bug #48985) * Privileges for stored routines were ignored for mixed-case routine names. (Bug #48872) See also Bug #41049. * Building MySQL on Fedora Core 12 64-bit failed, due to errors in *Note `comp_err': comp-err. (Bug #48864) * Concurrent *Note `ALTER TABLE': alter-table. operations on an *Note `InnoDB': innodb-storage-engine. table could raise an assertion. (Bug #48782) * Certain `INTERVAL' expressions could cause a crash on 64-bit systems. (Bug #48739) * During query execution, ranges could be merged incorrectly for `OR' operations and return an incorrect result. (Bug #48665) * The *Note `InnoDB': innodb-storage-engine. Table Monitor reported the *Note `FLOAT': numeric-types. and *Note `DOUBLE': numeric-types. data types incorrectly. (Bug #48526) * With row-based binary logging, the server crashed for statements of the form `CREATE TABLE IF NOT EXISTS EXISTING_VIEW LIKE TEMPORARY_TABLE'. This occurred because the server handled the existing view as a table when logging the statement. (Bug #48506) * `DISTINCT' was ignored for queries with `GROUP BY WITH ROLLUP' and only `const' tables. (Bug #48475) * Loose index scan was inappropriately chosen for some `WHERE' conditions. (Bug #48472) * The server could crash and corrupt the tablespace if the *Note `InnoDB': innodb-storage-engine. tablespace was configured with too small a value, or if many *Note `CREATE TEMPORARY TABLE': create-table. statements were executed and the temporary file directory filled up with `innodb_file_per_table' enabled. (Bug #48469) * Parts of the range optimizer could be initialized incorrectly, resulting in Valgrind errors. (Bug #48459) * A bad typecast could cause query execution to allocate large amounts of memory. (Bug #48458) * *Note `GRANT': grant. and *Note `REVOKE': revoke. crashed if a user name was specified as `CURRENT_USER()'. (Bug #48319) * On Windows, *Note `InnoDB': innodb-storage-engine. could not be built as a statically linked library. (Bug #48317) * *Note `mysql_secure_installation': mysql-secure-installation. did not work on Solaris. (Bug #48086) * When running *Note `mysql_secure_installation': mysql-secure-installation, the command would fail if the root password contained multiple spaces, \, # or quote characters. (Bug #48031) * `MATCH IN BOOLEAN MODE' searches could return too many results inside a subquery. (Bug #47930) * Using *Note `REPLACE': replace. to update a previously inserted negative value in an `AUTO_INCREMENT' coumn in an *Note `InnoDB': innodb-storage-engine. table caused the table auto-increment value to be updated to 2147483647. (Bug #47720) * If a session held a global read lock acquired with *Note `FLUSH TABLES WITH READ LOCK': flush, a lock for one table acquired with *Note `LOCK TABLES': lock-tables, and issued an *Note `INSERT DELAYED': insert-delayed. statement for another table, deadlock could occur. (Bug #47682) * The *Note `mysql': mysql. client `status' command displayed an incorrect value for the server character set. (Bug #47671) * Connecting to a 4.1.x server from a 5.1.x or higher *Note `mysql': mysql. client resulted in a memory-free error when disconnecting. (Bug #47655) * Assignment of a system variable sharing the same base name as a declared stored program variable in the same context could lead to a crash. (Bug #47627) * *Note `mysqladmin debug': mysqladmin. could crash on 64-bit systems. (Bug #47382) * The `innodb_file_format_check' system variable could not be set at runtime to `DEFAULT' or to the value of a user-defined variable. (Bug #47167) * The Mac OS X `MySQL Preference Pane' component was not built for 64-bit, which would trigger the System Preferences application to restart into 32-bit mode. (Bug #46935) * The `IGNORE' clause on a *Note `DELETE': delete. statement masked an SQL statement error that occurred during trigger processing. (Bug #46425) * On 64-bit systems, `--skip-innodb' did not skip *Note `InnoDB': innodb-storage-engine. startup. (Bug #46043) * Valgrind errors for `InnoDB Plugin' were corrected. (Bug #45992, Bug #46656) * The return value was not checked for some `my_hash_insert()' calls. (Bug #45613) * Truncation of *Note `DECIMAL': numeric-types. values could lead to assertion failures; for example, when deducing the type of a table column from a literal *Note `DECIMAL': numeric-types. value. (Bug #45261) See also Bug #48370. * For *Note `YEAR(2)': year. values, `MIN()', `MAX()', and comparisons could yield incorrect results. (Bug #43668) * The server could crash when attempting to access a non-conformant `mysql.proc' system table. For example, the server could crash when invoking stored procedure-related statements after an upgrade from MySQL 5.0 to 5.1 without running *Note `mysql_upgrade': mysql-upgrade. (Bug #41726) * Multiple-statement execution could fail. (Bug #40877) * Use of *Note `InnoDB': innodb-storage-engine. monitoring (*Note `SHOW ENGINE INNODB STATUS': show-engine. or one of the *Note `InnoDB': innodb-storage-engine. Monitor tables) could cause a server crash due to invalid access to a shared variable in a concurrent environment. This is a further fix for a regression introduced in MySQL 5.1.38 to the original fix in MySQL 5.1.31. (Bug #38883) * When running *Note `mysql_secure_installation': mysql-secure-installation. on Windows, the command would fail to load a required module, `Term::ReadKey', which was required for correct operation. (Bug #35106) * If the `--log-bin' server option was set to a directory name with a trailing component separator character, the basename of the binary log files was empty so that the created files were named `.000001' and `.index'. The same thing occurred with the `--log-bin-index', `--relay-log', and `--relay-log-index' options. Now the server reports and error and exits. (Bug #34739) * If a comparison involved a constant value that required type conversion, the converted value might not be cached, resulting in repeated conversion and poorer performance. (Bug #34384) * Using the *Note `SHOW ENGINE INNODB STATUS': show-engine. statement when using partitions in `InnoDB' tables caused `Invalid (old?) table or database name' errors to be logged. (Bug #32430) * On some Windows systems, `InnoDB' could report `Operating system error number 995 in a file operation' due to transient driver or hardware problems. `InnoDB' now retries the operation and adds `Retry attempt is made' to the error message. (Bug #3139)  File: manual.info, Node: news-5-1-41, Next: news-5-1-40sp1, Prev: news-5-1-42, Up: news-5-1-x D.1.23 Changes in MySQL 5.1.41 (05 November 2009) ------------------------------------------------- *InnoDB Notes* * `InnoDB Plugin' has been upgraded to version 1.0.5. This version is considered of Release Candidate (RC) quality. InnoDB Plugin Change History (http://dev.mysql.com/doc/innodb-plugin/1.0/en/innodb-changes.html), may contain information in addition to those changes reported here. *Functionality added or changed:* * *Incompatible Change*: For `InnoDB Plugin', two status variables have been added: `Innodb_buffer_pool_read_ahead' and `Innodb_buffer_pool_read_ahead_evicted' indicate the number of pages read in by the *Note `InnoDB': innodb-storage-engine. read-ahead background thread, and the number of such pages evicted without ever being accessed, respectively. Also, the status variables `Innodb_buffer_pool_read_ahead_rnd' and `Innodb_buffer_pool_read_ahead_seq' status variables have been removed. The built-in version of *Note `InnoDB': innodb-storage-engine. is not affected by these changes. (Bug #42885) * The *Note `InnoDB': innodb-storage-engine. buffer pool is divided into two sublists: A new sublist containing blocks that are heavily used by queries, and an old sublist containing less-used blocks and from which candidates for eviction are taken. In the default operation of the buffer pool, a block when read in is loaded at the midpoint and then moved immediately to the head of the new sublist as soon as an access occurs. In the case of a table scan (such as performed for a *Note `mysqldump': mysqldump. operation), each block read by the scan ends up moving to the head of the new sublist because multiple rows are accessed from each block. This occurs even for a one-time scan, where the blocks are not otherwise used by other queries. Blocks may also be loaded by the read-ahead background thread and then moved to the head of the new sublist by a single access. These effects can be disadvantageous because they push blocks that are in heavy use by other queries out of the new sublist to the old sublist where they become subject to eviction. `InnoDB' now provides two system variables that enable LRU algorithm tuning: * `innodb_old_blocks_pct' Specifies the approximate percentage of the buffer pool used for the old block sublist. The range of values is 5 to 95. The default value is 37 (that is, 3/8 of the pool). * `innodb_old_blocks_time' Specifies how long in milliseconds (ms) a block inserted into the old sublist must stay there after its first access before it can be moved to the new sublist. The default value is 0: A block inserted into the old sublist moves immediately to the new sublist the first time it is accessed, no matter how soon after insertion the access occurs. If the value is greater than 0, blocks remain in the old sublist until an access occurs at least that many ms after the first access. For example, a value of 1000 causes blocks to stay in the old sublist for 1 second after the first access before they become eligible to move to the new sublist. See *Note innodb-buffer-pool::. (Bug #45015) * The server now supports a Debug Sync facility for thread synchronization during testing and debugging. To compile in this facility, configure MySQL with the `--enable-debug-sync' option. The `debug_sync' system variable provides the user interface Debug Sync. *Note `mysqld': mysqld. and `mysql-test-run.pl' support a `--debug-sync-timeout' option to enable the facility and set the default synchronization point timeout. *Bugs fixed:* * *Important Change*: *Security Fix*: Additional corrections were made for the symlink-related privilege problem originally addressed in MySQL 5.1.24. The original fix did not correctly handle the data directory path name if it contained symlinked directories in its path, and the check was made only at table-creation time, not at table-opening time later. (Bug #32167, CVE-2008-2079) See also Bug #39277. * *Security Fix*: MySQL clients linked against OpenSSL could be tricked not to check server certificates. (Bug #47320, CVE-2009-4028) * *InnoDB Storage Engine*: When a trigger inserts into a table containing an auto-increment column, an error `Error: Duplicate entry' could occur with the InnoDB Plugin if another insert was happening simultaneously. (Bug #26316) * *Partitioning*: An *Note `ALTER TABLE ... ADD PARTITION': alter-table. statement that caused `open_files_limit' to be exceeded led to a MySQL server crash. (Bug #46922) See also Bug #47343. * *Partitioning*: The cardinality of indexes on partitioned tables was calculated using the first partition in the table, which could result in suboptimal query execution plans being chosen. Now the partition having the most records is used instead, which should result in better use of indexes and thus improved performance of queries against partitioned tables in many if not most cases. (Bug #44059) * *Replication*: This issue occurred in MySQL 5.1.40 only. (Bug #48297) * *Replication*: When a session was closed on the master, temporary tables belonging to that session were logged with the wrong database names when either of the following conditions was true: 1. The length of the name of the database to which the temporary table belonged was greater than the length of the current database name. 2. The current database was not set. (Bug #48216) See also Bug #46861, Bug #48297. * *Replication*: When using row-based replication, changes to nontransactional tables that occurred early in a transaction were not immediately flushed upon committing a statement. This behavior could break consistency since changes made to nontransactional tables become immediately visible to other connections. (Bug #47678) See also Bug #47287, Bug #46864, Bug #43929, Bug #11752675, Bug #46129. * *Replication*: When *Note `mysqlbinlog': mysqlbinlog. `--verbose' was used to read a binary log that had been written using row-based format, the output for events that updated some but not all columns of tables was not correct. (Bug #47323) * *Replication*: When using the row-based format to replicate a transaction involving both transactional and nontransactional engines, which contained a DML statement affecting multiple rows, the statement failed. If this transaction was followed by a *Note `COMMIT': commit, the master and the slave could diverge, because the statement was correctly rolled back on the master, but was applied on the slave. (Bug #47287) See also Bug #46864. * *Replication*: A problem with the `BINLOG' statement in the output of *Note `mysqlbinlog': mysqlbinlog. could break replication; statements could be logged with the server ID stored within events by the `BINLOG' statement rather than the ID of the running server. With this fix, the server ID of the server executing the statements can no longer be overridden by the server ID stored in the binary log's `format description' statement. (Bug #46640) This regression was introduced by Bug #32407. * *Replication*: When using statement-based replication and the transaction isolation level was set to `READ COMMITTED' or a less strict level, *Note `InnoDB': innodb-storage-engine. returned an error even if the statement in question was filtered out according to the `--binlog-do-db' or `--binlog-ignore-db' rules in effect at the time. (Bug #42829) * *Replication*: *Note `FLUSH LOGS': flush. did not close and reopen the binary log index file. (Bug #34582) See also Bug #48738. * `SUM()' artificially increased the precision of a *Note `DECIMAL': numeric-types. argument, which was truncated when a temporary table was created to hold the results. (Bug #48370) See also Bug #45261. * If an outer query was invalid, a subquery might not be set up. *Note `EXPLAIN EXTENDED': explain. did not expect this and caused a crash by trying to dereference improperly set up information. (Bug #48295) * A query containing a view using temporary tables and multiple tables in the `FROM' clause and `PROCEDURE ANALYSE()' caused a server crash. As a result of this bug fix, `PROCEDURE ANALYSE()' is legal only in a top-level `SELECT'. (Bug #48293) See also Bug #46184. * Error handling was missing for *Note `SELECT': select. statements containing subqueries in the `WHERE' clause and that assigned a *Note `SELECT': select. result to a user variable. The server could crash as a result. (Bug #48291) * An assertion could fail if the optimizer used a `SPATIAL' index. (Bug #48258, Bug #47019) * *Note `InnoDB': innodb-storage-engine. mishandled memory-allocation failures in the `os_mem_alloc_large()' function. (Bug #48237) * `WHERE' clauses with `OUTER_VALUE_LIST NOT IN SUBQUERY' were handled incorrectly if the outer value list contained multiple items at least one of which could be `NULL'. (Bug #48177) * A combination of `GROUP BY WITH ROLLUP', `DISTINCT' and the `const' join type in a query caused a server crash when the optimizer used a temporary table to resolve `DISTINCT'. (Bug #48131) * In some cases, using a null microsecond part in a `WHERE' condition (for example, `WHERE date_time_field <= 'YYYY-MM-DD HH:MM:SS.0000'') could lead to incorrect results due to improper *Note `DATETIME': datetime. comparison. (Bug #47963) * A build configured using the `--without-server' option did not compile the yaSSL code, so if `--with-ssl' was also used, the build failed. (Bug #47957) * When a query used a *Note `DATE': datetime. or *Note `DATETIME': datetime. value formatted using any separator characters other than hyphen (`'-'') and a `>=' condition matching only the greatest value in an indexed column, the result was empty if an index range scan was employed. (Bug #47925) * `mysys/mf_keycache.c' requires threading, but no test was made for thread support. (Bug #47923) * For debug builds, an assertion could fail during the next statement executed for a temporary table after a multiple-table *Note `UPDATE': update. involving that table modified an `AUTO_INCREMENT' column with a user-supplied value. (Bug #47919) * The `mysys/mf_strip.c' file, which defines the `strip_sp()' function, has been removed from the MySQL source. The function was no longer used within the main build, and the supplied function was causing symbol errors on Windows builds. (Bug #47857) * The Windows build for MySQL would compile the `split.c' and `debug.c' files unnecessarily, causing additional symbols to be included in *Note `mysqld': mysqld. (Bug #47850) * When building storage engines on Windows it was not possible to specify additional libraries within the `CMake' file required for the build. An `${engine}_LIBS' macro has been included in the files to support these additional storage-engine specific libraries. (Bug #47797) * When building a pluggable storage engine on Windows, the engine name could be based on the directory name where the engine was located, rather than the configured storage engine name. (Bug #47795) * During cleanup of a stored procedure's internal structures, the flag to ignore the errors for *Note `INSERT IGNORE': insert. or *Note `UPDATE IGNORE': update. was not cleaned up, which could result in a server crash. (Bug #47788) * If the first argument to `GeomFromWKB()' function was a geometry value, the function just returned its value. However, it failed to preserve the argument's `null_value' flag, which caused an unexpected `NULL' value to be returned to the caller, resulting in a server crash. (Bug #47780) * *Note `InnoDB': innodb-storage-engine. could crash when updating spatial values. (Bug #47777) * On Windows, when an idle named pipe connection was forcibly closed with a *Note `KILL': kill. statement or because the server was being shut down, the thread that was closing the connection would hang infinitely. As a result of the work done for this bug, the `net_read_timeout' and `net_write_timeout' system variables now apply to connections over all transports, not just to TCP/IP. (Bug #47571, Bug #31621) * A function call could end without throwing an error or setting the return value. For example, this could happen when an error occurred while calculating the return value. This is fixed by setting the value to `NULL' when an error occurs during evaluation of an expression. (Bug #47412) * A simple *Note `SELECT': select. with implicit grouping could return many rows rather than a single row if the query was ordered by the aggregated column in the select list. (Bug #47280) * An assertion could be raised for *Note `CREATE TABLE': create-table. if there was a pending *Note `INSERT DELAYED': insert. or *Note `REPLACE DELAYED': replace. for the same table. (Bug #47274) * `InnoDB' raised errors in some cases in a manner not compatible with `SIGNAL' and `RESIGNAL'. (Bug #47233) * If an *Note `InnoDB': innodb-storage-engine. table was created with the `AUTO_INCREMENT' table option to specify an initial auto-increment value, and an index was added in a separate operation later, the auto-increment value was lost (subsequent inserts began at 1 rather than the specified value). (Bug #47125) * Incorrect handling of predicates involving `NULL' by the range optimizer could lead to an infinite loop during query execution. (Bug #47123) * Repair by sort or parallel repair of *Note `MyISAM': myisam-storage-engine. tables might not fail over to repair with key cache. (Bug #47073) * `InnoDB Plugin' did not compile on some Solaris systems. (Bug #47058) * On Windows, when a failed I/O operation occurred with return code of `ERROR_WORKING_SET_QUOTA', *Note `InnoDB': innodb-storage-engine. intentionally crashed the server. Now *Note `InnoDB': innodb-storage-engine. sleeps for 100ms and retries the failed operation. (Bug #47055) * *Note `InnoDB': innodb-storage-engine. now ignores negative values supplied by a user for an `AUTO_INCREMENT' column when calculating the next value to store in the data dictionary. Setting `AUTO_INCREMENT' columns to negative values is undefined behavior and this change should bring the behavior of *Note `InnoDB': innodb-storage-engine. closer to what users expect. (Bug #46965) * When MySQL crashed (or a snapshot was taken that simulates a crash), it was possible that internal XA transactions (used to synchronize the binary log and *Note `InnoDB': innodb-storage-engine.) could be left in a `PREPARED' state, whereas they should be rolled back. This occurred when the `server_id' value changed before the restart, because that value was used to construct XID values. Now the restriction is relaxed that the `server_id' value be consistent for XID values to be considered valid. The rollback phase should then be able to clean up all pending XA transactions. (Bug #46944) * `InnoDB Plugin' did not compile using `gcc' 4.1 on PowerPC systems. (Bug #46718) * If `InnoDB Plugin' reached its limit on the number of concurrent transactions (1023), it wrote a descriptive message to the error log but returned a misleading error message to the client, or an assertion failure occurred. (Bug #46672) See also Bug #18828. * A Valgrind error during index creation by `InnoDB Plugin' was corrected. (Bug #46657) * Concurrent *Note `INSERT INTO ... SELECT': insert. statements for an `InnoDB' table could cause an `AUTO_INCREMENT' assertion failure. (Bug #46650) * If a transaction was rolled back inside *Note `InnoDB': innodb-storage-engine. due to a deadlock or lock wait timeout, and a statement in the transaction had an `IGNORE' clause, the server could crash at the end of the statement or on shutdown. (Bug #46539) * Trailing spaces were not ignored for user-defined collations that mapped spaces to a character other than 0x20. (Bug #46448) See also Bug #29468. * The GPL and commercial license headers had different sizes, so that error log, backtrace, core dump, and cluster trace file line numbers could be off by one if they were not checked against the version of the source used for the build. (For example, checking a GPL build backtrace against commercial sources.) (Bug #46216) * `InnoDB' did not disallow creation of an index with the name `GEN_CLUST_INDEX', which is used internally. (Bug #46000) * During the build of the Red Hat IA64 MySQL server RPM, the system library link order was incorrect. This made the resulting Red Hat IA64 RPM depend on "libc.so.6.1(GLIBC_PRIVATE)(64bit)", thus preventing installation of the package. (Bug #45706) * The `caseinfo' member of the `CHARSET_INFO' structure was not initialized for user-defined Unicode collations, leading to a server crash. (Bug #45645) * With `InnoDB Plugin', renaming a table column and then creating an index on the renamed column caused a server crash due to the `.frm' file and the `InnoDB' data directory going out of sync. Now `InnoDB Plugin' 1.0.5 returns an error instead: `ERROR 1034 (HY000): Incorrect key file for table 'TBL_NAME'; try to repair it'. To work around the problem, create another table with the same structure and copy the original table to it. (Bug #44571) * An *Note `InnoDB': innodb-storage-engine. error message incorrectly referred to the nonexistent `innodb_max_files_open' variable rather than to `innodb_open_files'. (Bug #44338) * For *Note `ALTER TABLE': alter-table, renaming a *Note `DATETIME': datetime. or *Note `TIMESTAMP': datetime. column unnecessarily caused a table copy operation. (Bug #43508) * The weekday names for the Romanian `lc_time_names' locale `'ro_RO'' were incorrect. Thanks to Andrei Boros for the patch to fix this bug. (Bug #43207) * *Note `XA START': xa. could cause an assertion failure or server crash when it is called after a unilateral rollback issued by the Resource Manager (both in a regular transaction and after an XA transaction). (Bug #43171) * The `FORCE INDEX FOR ORDER BY' index hint was ignored when join buffering was used. (Bug #43029) * Incorrect handling of range predicates combined with `OR' operators could yield incorrect results. (Bug #42846) * Failure to treat *Note `BIT': numeric-types. values as unsigned could lead to unpredictable results. (Bug #42803) * For the embedded server on Windows, *Note `InnoDB': innodb-storage-engine. crashed when `innodb_file_per_table' was enabled and a table name was in full path format. (Bug #42383) * Some queries with nested outer joins could lead to crashes or incorrect results because an internal data structure was handled improperly. (Bug #42116) * In a replication scenario with `innodb_locks_unsafe_for_binlog' enabled on the slave, where rows were changed only on the slave (not through replication), in some rare cases, many messages of the following form were written to the slave error log: `InnoDB: Error: unlock row could not find a 4 mode lock on the record'. (Bug #41756) * After renaming a user, granting that user privileges could result in the user having privileges additional to those granted. (Bug #41597) * With a nonstandard *Note `InnoDB': innodb-storage-engine. page size, some error messages became inaccurate. *Note*: Changing the page size is not a supported operation and there is no guarantee that *Note `InnoDB': innodb-storage-engine. will function normally with a page size other than 16KB. Problems compiling or running InnoDB may occur. In particular, `ROW_FORMAT=COMPRESSED' in the `InnoDB Plugin' assumes that the page size is at most 16KB and uses 14-bit pointers. A version of *Note `InnoDB': innodb-storage-engine. built for one page size cannot use data files or log files from a version built for a different page size. (Bug #41490) * In some cases, the server did not recognize lettercase differences between *Note `GRANT': grant. attributes such as table name or user name. For example, a user was able to perform operations on a table with privileges of another user with the same user name but in a different lettercase. In consequence of this bug fix, the collation for the `Routine_name' column of the `mysql.proc' table is changed from `utf8_bin' to `utf8_general_ci'. (Bug #41049) See also Bug #48872. * Simultaneous *Note `ANALYZE TABLE': analyze-table. operations for an *Note `InnoDB': innodb-storage-engine. tables could be subject to a race condition. (Bug #38996) * Previously, `InnoDB' performed `REPLACE INTO T SELECT ... FROM S WHERE ...' by setting shared next-key locks on rows from `S'. Now `InnoDB' selects rows from `S' with shared locks or as a consistent read, as for *Note `INSERT ... SELECT': insert-select. This reduces lock contention between sessions. (Bug #37232) * When an `InnoDB' tablespace filled up, an error was logged to the client, but not to the error log. Also, the error message was misleading and did not indicate the real source of the problem. (Bug #31183) * In *Note `mysql': mysql, using `Control+C' to kill the current query resulted in a `ERROR 1053 (08S01): Server shutdown in progress" message' if the query was waiting for a lock. (Bug #28141)  File: manual.info, Node: news-5-1-40sp1, Next: news-5-1-40, Prev: news-5-1-41, Up: news-5-1-x D.1.24 Release Notes for MySQL Enterprise 5.1.40sp1 [QSP] (25 November 2009) ---------------------------------------------------------------------------- This is a _Service Pack_ release of the MySQL Enterprise Server 5.1. *Bugs fixed:* * *Replication*: When using statement-based or mixed-format replication, the database name was not written to the binary log when executing a *Note `LOAD DATA INFILE': load-data. statement. This caused problems when the table being loaded belonged to a database other than the current database; data could be loaded into the wrong table (if a table having the same name existed in the current database) or replication could fail (if no table having that name existed in the current database). Now a table referenced in a *Note `LOAD DATA INFILE': load-data. statement is always logged using its fully qualified name when the database to which it belongs is not the current database. (Bug #48297) * *Replication*: When a session was closed on the master, temporary tables belonging to that session were logged with the wrong database names when either of the following conditions was true: 1. The length of the name of the database to which the temporary table belonged was greater than the length of the current database name. 2. The current database was not set. (Bug #48216) See also Bug #46861, Bug #48297. * `SUM()' artificially increased the precision of a *Note `DECIMAL': numeric-types. argument, which was truncated when a temporary table was created to hold the results. (Bug #48370) See also Bug #45261. * If an outer query was invalid, a subquery might not be set up. *Note `EXPLAIN EXTENDED': explain. did not expect this and caused a crash by trying to dereference improperly set up information. (Bug #48295) * A query containing a view using temporary tables and multiple tables in the `FROM' clause and `PROCEDURE ANALYSE()' caused a server crash. As a result of this bug fix, `PROCEDURE ANALYSE()' is legal only in a top-level `SELECT'. (Bug #48293) See also Bug #46184. * Error handling was missing for *Note `SELECT': select. statements containing subqueries in the `WHERE' clause and that assigned a *Note `SELECT': select. result to a user variable. The server could crash as a result. (Bug #48291) * An assertion could fail if the optimizer used a `SPATIAL' index. (Bug #48258, Bug #47019) * A combination of `GROUP BY WITH ROLLUP', `DISTINCT' and the `const' join type in a query caused a server crash when the optimizer used a temporary table to resolve `DISTINCT'. (Bug #48131) * In some cases, using a null microsecond part in a `WHERE' condition (for example, `WHERE date_time_field <= 'YYYY-MM-DD HH:MM:SS.0000'') could lead to incorrect results due to improper *Note `DATETIME': datetime. comparison. (Bug #47963) * When a query used a *Note `DATE': datetime. or *Note `DATETIME': datetime. value formatted using any separator characters other than hyphen (`'-'') and a `>=' condition matching only the greatest value in an indexed column, the result was empty if an index range scan was employed. (Bug #47925) * During cleanup of a stored procedure's internal structures, the flag to ignore the errors for *Note `INSERT IGNORE': insert. or *Note `UPDATE IGNORE': update. was not cleaned up, which could result in a server crash. (Bug #47788) * If the first argument to `GeomFromWKB()' function was a geometry value, the function just returned its value. However, it failed to preserve the argument's `null_value' flag, which caused an unexpected `NULL' value to be returned to the caller, resulting in a server crash. (Bug #47780) * *Note `InnoDB': innodb-storage-engine. could crash when updating spatial values. (Bug #47777) * Incorrect handling of predicates involving `NULL' by the range optimizer could lead to an infinite loop during query execution. (Bug #47123) * *Note `InnoDB': innodb-storage-engine. now ignores negative values supplied by a user for an `AUTO_INCREMENT' column when calculating the next value to store in the data dictionary. Setting `AUTO_INCREMENT' columns to negative values is undefined behavior and this change should bring the behavior of *Note `InnoDB': innodb-storage-engine. closer to what users expect. (Bug #46965) * In a replication scenario with `innodb_locks_unsafe_for_binlog' enabled on the slave, where rows were changed only on the slave (not through replication), in some rare cases, many messages of the following form were written to the slave error log: `InnoDB: Error: unlock row could not find a 4 mode lock on the record'. (Bug #41756)  File: manual.info, Node: news-5-1-40, Next: news-5-1-39, Prev: news-5-1-40sp1, Up: news-5-1-x D.1.25 Changes in MySQL 5.1.40 (06 October 2009) ------------------------------------------------ *InnoDB Notes* * In this release, the `InnoDB Plugin' is included in source and binary distributions, except RHEL3, RHEL4, SuSE 9 (x86, x86_64, ia64), and generic Linux RPM packages. It also does not work for FreeBSD 6 and HP-UX or for Linux on S/390, PowerPC, and generic ia64. *Bugs fixed:* * *Incompatible Change*: *Replication*: Concurrent transactions that inserted rows into a table with an `AUTO_INCREMENT' column could break statement-based or mixed-format replication error 1062 `Duplicate entry '...' for key 'PRIMARY'' on the slave. This was especially likely to happen when one of the transactions activated a trigger that inserted rows into the table with the `AUTO_INCREMENT' column, although other conditions could also cause the issue to manifest. As part of the fix for this issue, any statement that causes a trigger or function to update an `AUTO_INCREMENT' column is now considered unsafe for statement-based replication. For more information, see *Note replication-features-auto-increment::. (Bug #45677) See also Bug #42415, Bug #48608, Bug #50440, Bug #53079. * *Incompatible Change*: In binary installations of MySQL, the supplied `binary-configure' script would start and configure MySQL, even when command help was requested with the `--help' command-line option. The `--help' option, if provided, no longer starts and installs the server. (Bug #30954) * *Partitioning*: When reorganizing partitions, not all affected subpartitions were removed prior to renaming. One way in which the issue was visible was that attempting to reorganize two partitions into a single partition having the same name as one of the original partitions could lead to a crash of the server. (Bug #47029) See also Bug #45961, Bug #43729. * *Partitioning*: An online or fast *Note `ALTER TABLE': alter-table. of a partitioned table could leave behind temporary files in the database directory. This issue was observed in MySQL 5.1.31 and later only. (Bug #46483) * *Partitioning*: When performing an *Note `INSERT ... SELECT': insert-select. into a partitioned table, `read_buffer_size' bytes of memory were allocated for every partition in the target table, resulting in consumption of large amounts of memory when the table had many partitions (more than 100). This fix changes the method used to estimate the buffer size required for each partition and limits the total buffer size to a maximum of approximately 10 times `read_buffer_size'. (Bug #45840) * *Partitioning*: Inserting negative values into an `AUTO_INCREMENT' column of a partitioned table could lead to apparently unrelated errors or a crash of the server. (Bug #45823) * *Partitioning*: Unnecessary calls were made in the server code for performing bulk inserts on partitions for which no inserts needed to be made. (Bug #35845) See also Bug #35843. * *Replication*: Performing *Note `ALTER TABLE ... DISABLE KEYS': alter-table. on a slave table caused row-based replication to fail. (Bug #47312) * *Replication*: *Note `BEGIN': commit. statements were not included in the output of *Note `mysqlbinlog': mysqlbinlog. (Bug #46998) * *Replication*: When using row-based replication, *Note `DROP TEMPORARY TABLE IF EXISTS': drop-table. was written to the binary log if the table named in the statement did not exist, even though a *Note `DROP TEMPORARY TABLE': drop-table. statement should never be logged in row-based logging mode, whether the table exists or not. (Bug #46572) * *Replication*: When using row-based replication, importing a dump made with *Note `mysqldump': mysqldump. and replicating a row with an `AUTO_INCREMENT' column set to 0, with `NO_AUTO_VALUE_ON_ZERO' active on the master, the row was inserted successfully on the master; however any setting for `NO_AUTO_VALUE_ON_ZERO' was ignored on the slave. When the `AUTO_INCREMENT' column was incremented, this caused replication to fail on the slave due to a duplicate key error. In some cases it could also cause the slave to crash. (Bug #45999) * *Replication*: By default, all statements executed by the *Note `mysql_upgrade': mysql-upgrade. program on the master are written to the binary log, then replicated to the slave. In some cases, this can result in problems; for example, it attempted to alter log tables on replicated databases (this failed due to logging being enabled). As part of this fix, a *Note `mysql_upgrade': mysql-upgrade. option, `--write-binlog', is added. Its inverse, `--skip-write-binlog', can be used to disable binary logging while the upgrade is in progress. (Bug #43579) * *Replication*: On the master, if a binary log event is larger than `max_allowed_packet', the error message `ER_MASTER_FATAL_ERROR_READING_BINLOG' is sent to a slave when it requests a dump from the master, thus leading the I/O thread to stop. On a slave, the I/O thread stops when receiving a packet larger than `max_allowed_packet'. In both cases, however, there was no *Note `Last_IO_Error': show-slave-status. reported, which made it difficult to determine why the slave had stopped in such cases. Now, *Note `Last_IO_Error': show-slave-status. is reported when `max_allowed_packet' is exceeded, and provides the reason for which the slave I/O thread stopped. (Bug #42914) See also Bug #14068, Bug #47200, Bug #47303. * *API*: The fix for Bug#24507 could lead in some cases to client application failures due to a race condition. Now the server waits for the `dummy' thread to return before exiting, thus making sure that only one thread can initialize the POSIX threads library. (Bug #42850) * The `pthread_cond_wait()' implementations for Windows could deadlock in some rare circumstances. (Bug #47768) * On Mac OS X or Windows, sending a `SIGHUP' signal to the server or an asynchronous flush (triggered by `flush_time') caused the server to crash. (Bug #47525) * Debug builds could not be compiled with the Sun Studio compiler. (Bug #47474) * A multiple-table *Note `UPDATE': update. involving a natural join and a mergeable view raised an assertion. (Bug #47150) * Solaris binary packages now are compiled with `-g0' rather than `-g'. (Bug #47137) * *Note `EXPLAIN': explain. caused a server crash for certain valid queries. (Bug #47106) * The `configure' option `--without-server' did not work. (Bug #46980) * The *Note `ARCHIVE': archive-storage-engine. storage engine lost records during a bulk insert. (Bug #46961) * Failed multiple-table *Note `DELETE': delete. statements could raise an assertion. (Bug #46958) * When creating a new instance on Windows using *Note `mysqld-nt': mysqld. and the `--install' parameter, the value of the service would be set incorrectly, resulting in a failure to start the configured service. (Bug #46917) * `CONCAT_WS()' could return incorrect results due to an argument buffer also being used as a result buffer. (Bug #46815) * The server crashed when re-using outer column references in correlated subqueries when the enclosing query used a temp table. (Bug #46791) * For `InnoDB' tables, an unnecessary table rebuild for *Note `ALTER TABLE': alter-table. could sometimes occur for metadata-only changes. (Bug #46760) * Assertion failure could result from repeated execution of a stored procedure containing an incorrect query with a subselect. (Bug #46629) * The server ignored the setting of `sync_frm' for *Note `CREATE TABLE ... LIKE': create-table. (Bug #46591) * An attempt to create a table with the same name as an existing view could cause a server crash. (Bug #46384) * A parser problem prevented properly stripping backquotes from an argument to a user-defined function (UDF). If the UDF was in an `ORDER BY' clause, its name would not be properly resolved against an alias with the same name in the select list. (Bug #46259) * Dropping an `InnoDB' table that used an unknown collation (created on a different server, for example) caused a server crash. (Bug #46256) * Certain *Note `SELECT': select. statements containing `DISTINCT', `GROUP BY', and `HAVING' clauses could hang in an infinite loop. (Bug #46159) * `InnoDB' did not disallow creation of an index with the name `GEN_CLUST_INDEX', which is used internally. (Bug #46000) * `CREATE TEMPORARY TABLE' failed for `InnoDB' tables on systems with case-insensitive file systems when `lower_case_table_names' `= 2' and the pathname of the temporary file directory contained uppercase characters. (Bug #45638) * Appending values to an *Note `ENUM': enum. or *Note `SET': set. definition is a metadata change for which *Note `ALTER TABLE': alter-table. need not rebuild the table, but it was being rebuilt anyway. (Bug #45567) * The `socket' system variable was unavailable on Windows. (Bug #45498) * When re-installing MySQL on Windows on a server that has a data directory from a previous MySQL installation, the installer would fail to identify the existence of the installation and the password configured for the `root' user. (Bug #45200) * Client flags were incorrectly initialized for the embedded server, causing several tests in the `jp' test suite to fail. (Bug #45159) * `InnoDB' did not always disallow creating tables containing columns with names that match the names of internal columns, such as `DB_ROW_ID', `DB_TRX_ID', `DB_ROLL_PTR', and `DB_MIX_ID'. (Bug #44369) * *Note `SELECT ... WHERE ... IN (NULL, ...)': select. was executed using a full table scan, even if the same query without the `NULL' used an efficient range scan. (Bug #44139) See also Bug #18360. * `InnoDB' use of `SELECT MAX(AUTOINC_COLUMN)' could cause a crash when MySQL data dictionaries went out of sync. (Bug #44030) * *Note `LOAD DATA INFILE': load-data. statements were written to the binary log in such a way that parsing problems could occur when re-executing the statement from the log. (Bug #43746) * Selecting from the process list in the embedded server caused a crash. (Bug #43733) See also Bug #47304. * Attempts to enable `large_pages' with a shared memory segment larger than 4GB caused a server crash. (Bug #43606) * A test for stack growth failed on some platforms, leading to server crashes. (Bug #42213) * The server used the wrong lock type (always `TL_READ' instead of `TL_READ_NO_INSERT' when appropriate) for tables used in subqueries of *Note `UPDATE': update. statements. This led in some cases to replication failure because statements were written in the wrong order to the binary log. (Bug #42108) * The `mysql-stress-test.pl' test script was missing from the `noinstall' packages on Windows. (Bug #41546) * Privileges for *Note `SHOW CREATE VIEW': show-create-view. were not being checked correctly. (Bug #35996) * Different invocations of *Note `CHECKSUM TABLE': checksum-table. could return different results for a table containing columns with spatial data types. (Bug #35570) * Concurrent execution of *Note `FLUSH TABLES': flush. along with *Note `SHOW FUNCTION STATUS': show-function-status. or *Note `SHOW PROCEDURE STATUS': show-procedure-status. could cause a server crash. (Bug #34895) * *Note `myisamchk': myisamchk. performed parameter value casting at startup that generated unnecessary warning messages. (Bug #33785) * When using the *Note `ARCHIVE': archive-storage-engine. storage engine, `SHOW TABLE STATUS' displayed incorrect information for `Max_data_length', `Data_length' and `Avg_row_length'. (Bug #29203) * When building MySQL on Windows from source, the `WITH_BERKELEY_STORAGE_ENGINE' option would fail to configure `BDB' support correctly. (Bug #27693)  File: manual.info, Node: news-5-1-39, Next: news-5-1-38, Prev: news-5-1-40, Up: news-5-1-x D.1.26 Changes in MySQL 5.1.39 (04 September 2009) -------------------------------------------------- *Bugs fixed:* * *Performance*: For `MyISAM' tables with `bulk_insert_buffer_size' values larger than 256KB, the performance of bulk insert operations such as multiple-row *Note `INSERT': insert. and *Note `INSERT ... SELECT': insert. operations has been improved greatly when up to a hundred rows are inserted at the same time. (Bug #44723) * *Partitioning*: An *Note `INSERT ... SELECT': insert-select. statement on an empty partition of a partitioned table failed with `ERROR 1030 (HY000): Got error 124 from storage engine'. This issue also caused queries run against a partitioned table while a *Note `LOAD DATA CONCURRENT INFILE': load-data. statement was in progress to fail with the same error. (Bug #46639) See also Bug #35845, Bug #44657, Bug #45840. * *Partitioning*: A partitioned table having a *Note `TIMESTAMP': datetime. column with a default value of `CURRENT_TIMESTAMP' and this column was not defined using an `ON UPDATE' option, an *Note `ALTER TABLE ... REORGANIZE PARTITION': alter-table. statement on the table caused the *Note `TIMESTAMP': datetime. column value to be set to `CURRENT_TIMESTAMP' regardless. (Bug #46478) * *Partitioning*: Partition pruning did not always work correctly when the table's partitioning key used the `TO_DAYS()' function. (Bug #46362) * *Partitioning*: Attempting to access a partitioned table when partitioning support was disabled in a MySQL server binary that had been compiled with partitioning support caused the server to crash. (Bug #39893) * *Partitioning*: The use of `TO_DAYS()' in the partitioning expression led to selection failures when the column having the date value contained invalid dates. This occurred because the function returns `NULL' in such cases, and the partition containing NULL values was pruned away. For example, this problem occurred if `'2001-02-00'' was inserted into a *Note `DATE': datetime. column of such a table, and a subsequent query on this table used `WHERE DATE_COL < '2001-02-00''--while `'2001-01-01'' is less than `'2001-02-00'', `TO_DAYS('2001-02-00')' evaluates as `NULL', and so the row containing `'2001-01-01'' was not returned. Now, for tables using `RANGE' or `LIST' partitioning and having `TO_DAYS()' in the partitioning expression, the `NULL' partition is also scanned instead of being ignored. The fix for this issue also corrects misbehavior such that a query of the form `SELECT * FROM TABLE WHERE DATE_COL < DATE_VAL' on a table partitioned by `RANGE' or `LIST' was handled as though the server SQL mode included `ALLOW_INVALID_DATES' even if this was not actually part of the server SQL mode at the time the query was issued. (Bug #20577) See also Bug #18198, Bug #32021, Bug #46362. * *Replication*: Performing a multi-row update of the `AUTO_INCREMENT' column of a transactional table could result in an inconsistency between master and slave when there was a trigger on the transactional table that updated a nontransactional table. When such an update failed on the master, no rows were updated on the master, but some rows could (erroneously) be updated on the slave. (Bug #46864) * *Replication*: When using the `--replicate-rewrite-db' option and the database referenced by this option on the master was the current database when the connection to the slave was closed, any temporary tables existing in this database were not properly dropped. (Bug #46861) * *Replication*: When a statement that changed both transactional and nontransactional tables failed, the transactional changes were automatically rolled back on the master but the slave ignored the error and did not roll them back, thus leading to inconsistencies between master and slave. This issue is fixed by automatically rolling back a statement that fails on the slave; however, the transaction is not rolled back unless a corresponding *Note `ROLLBACK': commit. statement is found in the relay log file. (Bug #46130) See also Bug #33864. * *Replication*: When `slave_transaction_retries' is set, a statement that replicates, but is then rolled back due to a deadlock on the slave, should be retried. However, in certain cases, replication was stopped with error 1213 (`Deadlock found when trying to get lock; try restarting transaction') instead, even when this variable was set. (Bug #45694) * *Replication*: The binary logging behavior (and thus, the replication behavior) of *Note `CREATE DATABASE IF NOT EXISTS': create-database, *Note `CREATE TABLE IF NOT EXISTS': create-table, and *Note `CREATE EVENT IF NOT EXISTS': create-event. was not consistent among these statements, nor with that of *Note `DROP DATABASE IF EXISTS': drop-database, *Note `DROP TABLE IF EXISTS': drop-table, and *Note `DROP EVENT IF EXISTS': drop-event.: A `DROP ... IF EXISTS' statement is always logged even if the database object named in the statement does not exist. However, of the `CREATE ... IF NOT EXISTS' statements, only the *Note `CREATE EVENT IF NOT EXISTS': create-event. statement was logged when the database object named in the statement already existed. Now, every `CREATE ... IF NOT EXISTS' statement is written to the binary log (and thus replicated), whether the database object named in the statement exists or not. For more information, see *Note replication-features-create-if-not-exists::. Exception Replication and logging of *Note `CREATE TABLE IF NOT EXISTS ... SELECT': create-table. continues to be handled according to existing rules. See *Note replication-features-create-select::, for more information. (Bug #45574) * *Replication*: When using statement-based replication, database-level character sets were not always honored by the replication SQL thread. This could cause data inserted on the master using *Note `LOAD DATA': load-data. to be replicated using the wrong character set. *Note*: This was not an issue when using row-based replication. (Bug #45516) * *Replication*: In some cases, a *Note `STOP SLAVE': stop-slave. statement could cause the replication slave to crash. This issue was specific to MySQL on Windows or Macintosh platforms. (Bug #45238, Bug #45242, Bug #45243, Bug #46013, Bug #46014, Bug #46030) See also Bug #40796. * *Replication*: Creating a scheduled event whose `DEFINER' clause was either set to `CURRENT_USER' or not set explicitly caused the master and the slave to become inconsistent. This issue stems from the fact that, in both cases, the `DEFINER' is set to the `CURRENT_USER' of the current thread. (On the master, the `CURRENT_USER' is the *Note `mysqld': mysqld. user; on the slave, the `CURRENT_USER' is empty.) This behavior has been modified as follows: * If `CURRENT_USER' is used as the `DEFINER', it is replaced with the _value_ of `CURRENT_USER' before the *Note `CREATE EVENT': create-event. statement is written to the binary log. * If the definer is not set explicitly, a `DEFINER' clause using the value of `CURRENT_USER' is added to the *Note `CREATE EVENT': create-event. statement before it is written to the binary log. (Bug #44331) See also Bug #42217. * *Replication*: When using the statement-based logging format, the only possible safe combination of transactional and nontransactional statements within the same transaction is to perform any updates on nontransactional tables (such as *Note `MyISAM': myisam-storage-engine. tables) first, before updating any transactional tables (such as those using the *Note `InnoDB': innodb-storage-engine. storage engine). This is due to the fact that, although a modification made to a nontransactional table is immediately visible to other connections, the update is not immediately written to the binary log, which can lead to inconsistencies between master and slave. (Other combinations may hide a causal dependency, thus making it impossible to write statements updating nontransactional tables to the binary log in the correct order.) However, in some cases, this situation was not handled properly, and the determination whether a given statement was safe or not under these conditions was not always correct. In particular, a multi-table update that affected both transactional and nontransactional tables or a statement modifying data in a nontransactional table having a trigger that operated on a transactional table (or the reverse) was not determined to be unsafe when it should have been. With this fix, the following determinations regarding replication safety are made when combining updates to transactional and nontransactional tables within the same transaction in statement-based logging mode: 1. Any statement modifying data in a nontransactional table within a given transaction is considered safe if it is issued prior to any data modification statement accessing a transactional table within the same transaction. 2. A statement that updates transactional tables only is always considered safe. 3. A statement affecting both transactional and nontransactional tables within a transaction is always considered unsafe. It is not necessary that both tables be modified for this to be true; for example, a statement such as `INSERT INTO INNODB_TABLE SELECT * FROM MYISAM_TABLE' is also considered unsafe. *Note*: The current fix is valid only when using statement-based logging mode; we plan to address similar issues occurring when using the `MIXED' or `ROW' format in a future MySQL release. (Bug #28976) * Stack overflow checking did not account for the size of the structure stored in the heap. (Bug #46807) * The server could crash for queries with the following elements: 1. An `impossible where' in the outermost `SELECT'; 2. An aggregate in the outermost `SELECT'; 3. A correlated subquery with a `WHERE' clause that includes an outer field reference as a top-level `WHERE' sargable predicate; (Bug #46749) * *Note `CREATE TABLE ... SELECT': create-table. could cause assertion failure if a table already existed with the same name and contained an `AUTO_INCREMENT' column. (Bug #46616) * *Note `SHOW CREATE TRIGGER': show-create-trigger. for a *Note `MERGE': merge-storage-engine. table trigger caused an assertion failure. (Bug #46614) * In queries for which the loose index scan access method was chosen, using a condition of the form COL_NAME rather than the equivalent `COL_NAME <> 0' caused an assertion failure. (Bug #46607) * *Note `TRUNCATE TABLE': truncate-table. for a table that was opened with *Note `HANDLER': handler. did not close the handler and left it in an inconsistent state that could lead to a server crash. Now *Note `TRUNCATE TABLE': truncate-table. for a table closes all open handlers for the table. (Bug #46456) * A query containing a subquery in the `FROM' clause and `PROCEDURE ANALYSE()' caused a server crash. (Bug #46184) See also Bug #48293. * Killing a query that was performing a sort could result in a memory leak. (Bug #45962) * Truncation of *Note `DECIMAL': numeric-types. values could lead to assertion failures; for example, when deducing the type of a table column from a literal *Note `DECIMAL': numeric-types. value. (Bug #45261) See also Bug #48370. * A buffer overflow could occur during handling of `IS NULL' ranges. (Bug #37044) * *Note `mysqladmin --wait ping': mysqladmin. crashed on Windows systems. (Bug #35132) * Installation of MySQL on Windows would fail to set the correct location for the character set files, which could lead to *Note `mysqld': mysqld. and *Note `mysql': mysql. failing to initialize properly. (Bug #17270)  File: manual.info, Node: news-5-1-38, Next: news-5-1-37sp1, Prev: news-5-1-39, Up: news-5-1-x D.1.27 Changes in MySQL 5.1.38 (01 September 2009) -------------------------------------------------- *InnoDB Notes* * As of MySQL 5.1.38, the `InnoDB Plugin' is included in MySQL 5.1 releases, in addition to the built-in version of `InnoDB' that has been included in previous releases. The version of the `InnoDB Plugin' in this release is 1.0.4 and is considered of Beta quality. The `InnoDB Plugin' offers new features, improved performance and scalability, enhanced reliability and new capabilities for flexibility and ease of use. Among the features of the `InnoDB Plugin' are `Fast index creation,' table and index compression, file format management, new `INFORMATION_SCHEMA' tables, capacity tuning, multiple background I/O threads, and group commit. For information about these features, see InnoDB Plugin 1.0 for MySQL 5.1 User's Guide (http://dev.mysql.com/doc/innodb-plugin/1.0/en/index.html). For general information about using `InnoDB' in MySQL, see *Note innodb-storage-engine::. The `InnoDB Plugin' is included in source and binary distributions, except RHEL3, RHEL4, SuSE 9 (x86, x86_64, ia64), and generic Linux RPM packages. For instructions on replacing the built-in version of `InnoDB' with `InnoDB Plugin', see *Note replacing-builtin-innodb::. *Functionality added or changed:* * *Replication*: With statement-based logging (SBL), repeatedly calling statements that are unsafe for SBL caused a warning message to be written to the error log for each statement, and there was no way to disable this behavior. Now the server logs messages about statements that are unsafe for statement-based logging only if the `log_warnings' variable is greater than 0. (Bug #46265) * The undocumented `TRANSACTIONAL' and `PAGE_CHECKSUM' keywords were removed from the grammar. (Bug #45829) * Previously, *Note `mysqldump': mysqldump. would not dump the `INFORMATION_SCHEMA' database and ignored it if it was named on the command line. Now, *Note `mysqldump': mysqldump. will dump `INFORMATION_SCHEMA' if it is named on the command line. Currently, this requires that the `--skip-lock-tables' (or `--skip-opt') option be given. (Bug #33762) * Previously, *Note `SELECT ... INTO OUTFILE': select. dumped column values without character set conversion, which could produce data files that cannot be imported without error if different columns used different character sets. A consequence of this is that *Note `mysqldump': mysqldump. ignored the `--default-character-set' option if the `--tab' option was given (which causes *Note `SELECT ... INTO OUTFILE': select. to be used to dump data.) `INTO OUTFILE' now can be followed by a `CHARACTER SET' clause indicating the character set to which dumped values should be converted. Also, *Note `mysqldump': mysqldump. adds a `CHARACTER SET' clause to the *Note `SELECT ... INTO OUTFILE': select. statement used to dump data, so that `--default-character-set' is no longer ignored if `--tab' is given. Other changes are that *Note `SELECT ... INTO OUTFILE': select. enforces that `ENCLOSED BY' and `ESCAPED BY' arguments must be a single character, and *Note `SELECT ... INTO OUTFILE': select. and *Note `LOAD DATA INFILE': load-data. produce warnings if non-ASCII field or line separators are specified. (Bug #30946) * Pluggable storage engines now can be built for Windows. * The MySQL `euckr' character set now can store extended codes [81...FE][41..5A,61..7A,81..FE], which makes `euckr' compatible with the Microsoft `cp949' character set. *Bugs fixed:* * *Performance*: The table cache lock (`LOCK_open') is now an adaptive mutex, which should improve performance in workloads where this lock is heavily contended. (Bug #43435) * *Partitioning*: Attempting to create a table using an invalid or inconsistent subpartition definition caused the server to crash. An example of such a statement is shown here: CREATE TABLE t2 (s1 INT, s2 INT) PARTITION BY LIST (s1) SUBPARTITION BY HASH (s2) SUBPARTITIONS 1 ( PARTITION p1 VALUES IN (1), PARTITION p2 VALUES IN (2) (SUBPARTITION p3) ); (Bug #46354) * *Partitioning*: When using a debug build of MySQL, if a query against a partitioned table having an index on one or more *Note `DOUBLE': numeric-types. columns used that index, the server failed with an assertion. (Bug #45816) * *Partitioning*: A failed *Note `RENAME TABLE': rename-table. operation on a table with user-defined partitioning left the table in an unusable state, due to only some of the table files having been renamed. (Bug #30102) * *Replication*: When a statement that changes a nontransactional table failed, the transactional cache was flushed, causing a mismatch between the execution and logging histories. Now we avoid flushing the transactional cache unless a *Note `COMMIT': commit. or *Note `ROLLBACK': commit. is issued. (Bug #46129) * *Replication*: The internal function `get_master_version_and_clock()' (defined in `sql/slave.cc') ignored errors and passed directly when queries failed, or when queries succeeded but the result retrieved was empty. Now this function tries to reconnect the master if a query fails due to transient network problems, and to fail otherwise. The I/O thread now prints a warning if the same system variables do not exist on master (in the event the master is a very old version of MySQL, compared to the slave.) (Bug #45214) * *Replication*: When using the `MIXED' logging format, after creating a temporary table and performing an update that switched the logging format to `ROW', the format switch persisted following the update. This prevented any subsequent DDL statements on temporary tables from being written to the binary log until the temporary table was dropped. (Bug #43046) See also Bug #40013. This regression was introduced by Bug #20499. * *Replication*: If the `--log-bin-trust-function-creators' option is not enabled, *Note `CREATE FUNCTION': create-procedure. requires one of the modifiers `DETERMINISTIC', `NO SQL', or `READS SQL DATA'. When using statement-based mode, the execution of a stored function should follow the same rules; however, only functions defined with `DETERMINISTIC' could actually be executed. In addition, the wrong error was generated (`ER_BINLOG_ROW_RBR_TO_SBR' instead of `ER_BINLOG_UNSAFE_ROUTINE'). Now execution of stored functions is compatible with creation in this regard; when a stored function without one of the modifiers above is executed in `STATEMENT' mode, the correct error is raised, and functions defined using `NO SQL', `READS SQL DATA', or both (that is, without using `DETERMINISTIC') can be excuted. (Bug #41166) * The test suite was missing from RPM packages. (Bug #46834) * Incorrect index optimization could lead to incorrect results or server crashes. (Bug #46454) * The server printed warnings at startup about adjusting the value of the `max_join_size' system variable. (These were harmless, but might be seen by users as significant.) (Bug #46385) * *Note `mysql': mysql. did not handle backspace properly for multi-byte characters. This has been fixed now if *Note `mysql': mysql. is linked with the `readline' library. It is not fixed if `mysql' is linked with `libedit', which does not contain the necessary support for multi-byte character sets. (Bug #46310) * After an error such as a table-full condition, *Note `INSERT IGNORE': insert. could cause an assertion failure for debug builds. (Bug #46075) * An optimization that moved an item from a subquery to an outer query could cause a server crash. (Bug #46051) * Several Valgrind warnings were corrected. (Bug #46003, Bug #46034, Bug #46042) * *Note `CREATE TABLE ... SELECT': create-table. could cause a server crash if no default database was selected. (Bug #45998) * The MySQL Server crashed when performing a `REPLACE' into a `MERGE' table if there was a duplicate. (Bug #45800) * An infinite hang and 100% CPU usage occurred after a handler tried to open a merge table. If the command *Note `mysqladmin shutdown': mysqladmin. was executed during the hang, the debug server generated the following assert: mysqld: table.cc:407: void free_table_share(TABLE_SHARE*): Assertion `share->ref_count == 0' failed. 090610 14:54:04 - mysqld got signal 6 ; (Bug #45781) * For problems reading SSL files during SSL initialization, the server wrote error messages to `stderr' rather than to the error log. (Bug #45770) * The vendor name change from MySQL AB to Sun Microsystems, Inc. in RPM packages was not handled gracefully when upgrading MySQL using an RPM package. (Bug #45534) * A Windows Installation using the GUI installer would fail with: MySQL Server 5.1 Setup Wizard ended prematurely The wizard was interrupted before MySQL Server 5.1. could be completely installed. Your system has not been modified. To complete installation at another time, please run setup again. Click Finish to exit the wizard This was due to an step in the MSI installer that could fail to execute correctly on some environments. (Bug #45418) * Invalid memory reads could occur using the compressed client/server protocol. (Bug #45031) * The *Note `mysql_real_connect()': mysql-real-connect. C API function only attempted to connect to the first IP address returned for a hostname. This could be a problem if a hostname mapped to multiple IP address and the server was not bound to the first one returned. Now *Note `mysql_real_connect()': mysql-real-connect. attempts to connect to all IPv4 or IPv6 addresses that a domain name maps to. (Bug #45017) See also Bug #47757. * Invalid input could cause invalid memory reads by the parser. (Bug #45010) * Some files in an AIX `tar' file distribution unpacked with incorrect permissions. (Bug #44647) * For debug builds, executing a stored procedure as a prepared statement could sometimes cause an assertion failure. (Bug #44521) * Using *Note `mysql_stmt_execute()': mysql-stmt-execute. to call a stored procedure could cause a server crash. (Bug #44495) * Creating a new instance after previously removing an instance would fail to complete the installation properly because the security settings could not be applied correctly. (Bug #44428) * *Note `mysqlslap': mysqlslap. ignored the `--csv' option if it was given without an argument. (Bug #44412) * Enabling the event scheduler from within the file specified by `--init-file' caused a server crash. (Bug #43587) * The server did not always check the return value of calls to the `hash_init()' function. (Bug #43572) * *Note `mysqladmin --count=X --sleep=Y': mysqladmin. incorrectly delayed Y seconds after the last iteration before exiting. (Bug #42639) * A test for stack growth failed on some platforms, leading to server crashes. (Bug #42213) * *Note `mysqladmin': mysqladmin. did not have enough space allocated for tracking all variables when using `--vertical' or `--relative' with `extended-status'. (Bug #40395) * Partitioning a log table caused a server crash. (Bug #40281) * When using quick access methods to search for rows in `UPDATE' and `DELETE' statements, there was no check whether a fatal error had already been sent to the client while evaluating the quick condition. Consequently, a false OK (following the error) was sent to the client, causing the error to be incorrectly transformed into a warning. (Bug #40113) * *Note `SHOW PROCESSLIST': show-processlist. could access freed memory of a stored procedure run in a concurrent session. (Bug #38816) * During installation on Windows, the MySQL Instance Configuration Wizard window could be opened at a size too small to be usable. (Bug #38723) * `make_binary_distribution' did not always generate correct distribution names. (Bug #37808) * The server crashed when executing a prepared statement containing a duplicated `MATCH()' function call in the select list and `ORDER BY' clause; for example, `SELECT MATCH(a) AGAINST('test') FROM t1 ORDER BY MATCH(a) AGAINST('test')'. (Bug #37740) * The output of *Note `mysqldump --tab': mysqldump. for views included a *Note `DROP TABLE': drop-table. statement without the `IF EXISTS' qualifier. (Bug #37377) * *Note `mysql_upgrade': mysql-upgrade. silently ignored the `--basedir' and `--datadir' options, which it accepts for backward compatibility. Now it prints a warning. (Bug #36558) * *Note `mysqlimport': mysqlimport. was not always compiled correctly to enable thread support, which is required for the `--use-threads' option. (Bug #32991) * *Note `mysqlcheck': mysqlcheck. failed to fix table names when the `--fix-table-names' and `--all-in-1' options were both specified. (Bug #31821) * If the MySQL server was killed without the PID file being removed, attempts to stop the server with *Note `mysql.server stop': mysql-server. waited 900 seconds before giving up. (Bug #31785) * When performing an installation on Windows using the GUI installer, the installer would fail to wait long enough during installation for the MySQL service to be installed, which would cause the installation to fail and may cause security settings, such as the `root' password to not be applied correctly. (Bug #30525) * *Note `mysql': mysql. included extra spaces at the end of some result set lines. (Bug #29622) * The *Note `mysql': mysql. client inconsistently handled NUL bytes in column data in various output formats. (Bug #28203) * *Note `mysqlimport': mysqlimport. did not correctly quote and escape table identifiers and file names. (Bug #28071) * When installing the Windows service, using quotation marks around command-line configuration parameters could cause the quotation marks to be incorrectly placed around the entire command-line option, and not just the value. (Bug #27535) * If the *Note `mysql': mysql. client was built with the `readline' library and the `.inputrc' file mapped `Space' to the `magic-space' function, it became impossible to enter spaces. (Bug #27439) * If `InnoDB' reached its limit on the number of concurrent transactions (1023), it wrote a descriptive message to the error log but returned a misleading error message to the client, or an assertion failure occurred. (Bug #18828) See also Bug #46672.  File: manual.info, Node: news-5-1-37sp1, Next: news-5-1-37, Prev: news-5-1-38, Up: news-5-1-x D.1.28 Release Notes for MySQL Enterprise 5.1.37sp1 [QSP] (10 October 2009) --------------------------------------------------------------------------- This is a _Service Pack_ release of the MySQL Enterprise Server 5.1. *Bugs fixed:* * The test suite was missing from RPM packages. (Bug #46834) * The server could crash for queries with the following elements: 1. An `impossible where' in the outermost `SELECT'; 2. An aggregate in the outermost `SELECT'; 3. A correlated subquery with a `WHERE' clause that includes an outer field reference as a top-level `WHERE' sargable predicate; (Bug #46749) * *Note `SHOW CREATE TRIGGER': show-create-trigger. for a *Note `MERGE': merge-storage-engine. table trigger caused an assertion failure. (Bug #46614) * Incorrect index optimization could lead to incorrect results or server crashes. (Bug #46454) * A query containing a subquery in the `FROM' clause and `PROCEDURE ANALYSE()' caused a server crash. (Bug #46184) See also Bug #48293. * *Note `CREATE TABLE ... SELECT': create-table. could cause a server crash if no default database was selected. (Bug #45998) * A Windows Installation using the GUI installer would fail with: MySQL Server 5.1 Setup Wizard ended prematurely The wizard was interrupted before MySQL Server 5.1. could be completely installed. Your system has not been modified. To complete installation at another time, please run setup again. Click Finish to exit the wizard This was due to an step in the MSI installer that could fail to execute correctly on some environments. (Bug #45418) * For debug builds, executing a stored procedure as a prepared statement could sometimes cause an assertion failure. (Bug #44521) * Using *Note `mysql_stmt_execute()': mysql-stmt-execute. to call a stored procedure could cause a server crash. (Bug #44495)  File: manual.info, Node: news-5-1-37, Next: news-5-1-36, Prev: news-5-1-37sp1, Up: news-5-1-x D.1.29 Changes in MySQL 5.1.37 (13 July 2009) --------------------------------------------- *Functionality added or changed:* * *Important Change*: *Replication*: *Note `RESET MASTER': reset-master. and *Note `RESET SLAVE': reset-slave. now reset the values shown for `Last_IO_Error', `Last_IO_Errno', `Last_SQL_Error', and `Last_SQL_Errno' in the output of *Note `SHOW SLAVE STATUS': show-slave-status. (Bug #44270) See also Bug #34654. *Bugs fixed:* * *Performance*: With `InnoDB' tables, MySQL used a less-selective secondary index to avoid a filesort even if a prefix of the primary key was much more selective. The fix for this problem might cause other queries to run more slowly. (Bug #45828) * *Partitioning*: *Security Fix*: Accessing a table having user-defined partitioning when the server SQL mode included `ONLY_FULL_GROUP_BY' caused the MySQL server to crash. For example, the following sequence of statements crashed the server: DROP TABLE IF EXISTS t1; SET SESSION sql_mode='ONLY_FULL_GROUP_BY'; CREATE TABLE t1 (id INT, KEY(id)) PARTITION BY HASH(id) PARTITIONS 2; (Bug #45807) * *Security Fix*: The `strxnmov()' library function could write a null byte after the end of the destination buffer. (Bug #44834) * *Important Change*: *Replication*: When using `STATEMENT' or `MIXED' binary logging format, a statement that changes both nontransactional and transactional tables must be written to the binary log whenever there are changes to nontransactional tables. This means that the statement goes into the binary log even when the changes to the transactional tables fail. In particular, in the event of a failure such statement is annotated with the error number and wrapped inside a pair of *Note `BEGIN': commit. and *Note `ROLLBACK': commit. statements. On the slave, while applying the statement, it is expected that the same failure and the rollback prevent the transactional changes from persisting. However, statements that fail due to concurrency issues such as deadlocks and timeouts are logged in the same way, causing the slave to stop since the statements are applied sequentially by the SQL thread. To address this issue, we ignore concurrency failures on the slave. Specifically, the following failures are now ignored: `ER_LOCK_WAIT_TIMEOUT', `ER_LOCK_DEADLOCK', and `ER_XA_RBDEADLOCK'. (Bug #44581) * *Partitioning*: Truncating a partitioned `MyISAM' table did not reset the `AUTO_INCREMENT' value. (Bug #35111) * *Replication*: The *Note `SHOW SLAVE STATUS': show-slave-status. connection thread competed with the slave SQL thread for use of the error message buffer. As a result, the connection thread sometimes received incomplete messages. This issue was uncovered with `valgrind' when message strings were passed without `NULL' terminators, causing the error `Conditional jump or move depends on uninitialised value(s)'. (Bug #45511) See also Bug #43076. * *Replication*: For replication of a stored procedure that uses the `gbk' character set, the result on the master and slave differed. (Bug #45485) * *Replication*: The internal function `purge_relay_logs()' did not propagate an error occurring in another internal function `count_relay_log_space()'. (Bug #44115) * *Replication*: Large transactions and statements could corrupt the binary log if the size of the cache (as set by `max_binlog_cache_size') was not large enough to store the changes. Now, for transactions that do not fit into the cache, the statement is not logged, and the statement generates an error instead. For nontransactional changes that do not fit into the cache, the statement is also not logged--an incident event is logged after committing or rolling back any pending transaction, and the statement then raises an error. *Note*: If a failure occurs before the incident event is written the binary log, the slave does not stop, and the master does not report any errors. (Bug #43929, Bug #11752675) See also Bug #37148, Bug #11748696, Bug #46166, Bug #11754544. * *Replication*: The `--database' option for *Note `mysqlbinlog': mysqlbinlog. was ignored when using the row-based logging format. (Bug #42941) * *Replication*: Statements using `LIMIT' generated spurious `Statement is not safe to log in statement format' warnings in the error log, causing the log to grow rapidly in size. (Bug #42851) See also Bug #46265, Bug #42415. This regression was introduced by Bug #34768. * *Replication*: Shutting down the slave while executing `FLUSH LOGS', *Note `CHANGE MASTER TO': change-master-to, or *Note `STOP SLAVE': stop-slave. could sometimes cause it to crash. (Bug #38240) * *Replication*: When reading a binary log that was in use by a master or that had not been properly closed (possibly due to a crash), the following message was printed: `Warning: this binlog was not closed properly. Most probably mysqld crashed writing it'. This message did not take into account the possibility that the file was merely in use by the master, which caused some users concern who were not aware that this could happen. To make this clear, the original message has been replaced with `Warning: this binlog is either is use or was not closed properly'. (Bug #34687) * The server crashed if evaluation of `GROUP_CONCAT(... ORDER BY)' required allocation of a sort buffer but allocation failed. (Bug #46080) * When creating tables using the `IBMDB2I' storage engine with the `ibmdb2i_create_index_option' option set to 1, creating an `IBMDB2I' table with a primary key should produce an additional index that uses EBCDIC hexadecimal sorting, but this index was not created. (Bug #45983) * The server crashed for attempts to use *Note `REPLACE': replace. or *Note `INSERT ... ON DUPLICATE KEY UPDATE': insert. with a view defined using a join. (Bug #45806) * Some collations were causing `IBMDB2I' to report inaccurate key range estimations to the optimizer for `LIKE' clauses that select substrings. This can be seen by running *Note `EXPLAIN': explain. This problem primarily affects multi-byte and unicode character sets. (Bug #45803) * Invalid memory reads and writes were generated when altering merge and base tables. This could lead to a crash or Valgrind errors: ==28038== Invalid write of size 1 at: memset (mc_replace_strmem.c:479) by: myrg_attach_children (myrg_open.c:433) by: ha_myisammrg::attach_children() (ha_myisammrg.cc:546) by: ha_myisammrg::extra(ha_extra_function) (ha_myisammrg.cc:944) by: attach_merge_children(TABLE_LIST*) (sql_base.cc:4147) by: open_tables(THD*, TABLE_LIST**, unsigned*, unsigned) (sql_base.cc:4709) by: open_and_lock_tables_derived(THD*, TABLE_LIST*, bool) (sql_base.cc:4977) by: open_n_lock_single_table (mysql_priv.h:1550) by: mysql_alter_table(sql_table.cc:6428) by: mysql_execute_command(THD*) (sql_parse.cc:2860) by: mysql_parse(THD*, char const*, unsigned, char const**) (sql_parse.cc:5933) by: dispatch_command (sql_parse.cc:1213) (Bug #45796) * Inserting data into a table using the `macce' character set with the `IBMDB2I' storage engine would fail. (Bug #45793) * There was a race condition when changing `innodb_commit_concurrency' at runtime to the value `DEFAULT'. (Bug #45749) See also Bug #42101. * Performing an empty XA transaction caused the server to crash for the next XA transaction. (Bug #45548) * *Note `SHOW CREATE TRIGGER': show-create-trigger. requires the `TRIGGER' privilege but was not checking privileges. (Bug #45412) * An assertion failure could occur if `InnoDB' tried to unlock a record when the clustered index record was unknown. (Bug #45357) * `--enable-PLUGIN_NAME' options (for example, `--enable-innodb') did not work correctly. (Bug #45336) See also Bug #19027. * If `autocommit' was enabled, `InnoDB' did not roll back *Note `DELETE': delete. or *Note `UPDATE': update. statements if the statement was killed. (Bug #45309) * The optimizer mishandled `impossible range' conditions and returned empty results due to an uninitialized variable. (Bug #45266) * Use of *Note `DECIMAL': numeric-types. constants with more than 65 digits in *Note `CREATE TABLE ... SELECT': create-table. statements led to spurious errors or assertion failures. (Bug #45262) * The *Note `mysql': mysql. client could misinterpret some character sequences as commands under some circumstances. (Bug #45236) * Use of `CONVERT()' with an empty *Note `SET': set. value could cause an assertion failure. (Bug #45168) * `InnoDB' recovery could hang due to redo logging of doublewrite buffer pages. (Bug #45097) * When reading binary data, the concatenation function for geometry data collections did not rigorously check for available data, leading to invalid reads and server crashes. (Bug #44684) * If an error occurred during the creation of a table (for example, the table already existed) having an `AUTO_INCREMENT' column and a `BEFORE' trigger that used the *Note `INSERT ... SELECT': insert-select. construct, an internal flag was not reset properly. This led to a crash the next time the table was opened again. (Bug #44653) * `configure.in' contained references to literal instances of `nm' and `libc', rather than to variables parameterized for the proper values on the current platform. (Bug #42721) * `configure.in' did not properly check for the `pthread_setschedprio()' function. (Bug #42599) * *Note `SHOW ERRORS': show-errors. returned an empty result set after an attempt to drop a nonexistent table. (Bug #42364) * A workaround for a Sun Studio bug was instituted. (Bug #41710) * For queries with a sufficient number of subqueries in the `FROM' clause of this form: SELECT * FROM (SELECT 1) AS t1, (SELECT 2) AS t2, (SELECT 3) AS t3, ... The query failed with a `Too high level of nesting for select' error, as though the query had this form: SELECT * FROM (SELECT 1 FROM (SELECT 2 FROM (SELECT 3 FROM ... (Bug #41156) * Some *Note `UPDATE': update. statements that affected no rows returned a rows-affected count of one. (Bug #40565) * Valgrind warnings that occurred for *Note `SHOW TABLE STATUS': show-table-status. with `InnoDB' tables were silenced. (Bug #38479) * In the *Note `mysql': mysql. client, if the server connection was lost during repeated `status' commands, the client would fail to detect this and command output would be inconsistent. (Bug #37274) * A Valgrind error during subquery execution was corrected. (Bug #36995) * When invoked to start multiple server instances, *Note `mysqld_multi': mysqld-multi. sometimes would fail to start them all due to not changing location into the base directory for each instance. (Bug #36654) * Rows written to the slow query log could have an indeterminate `Rows_examined' value due to improper initialization. (Bug #34002) * Renaming a column that appeared in a foreign key definition did not update the foreign key definition with the new column name. (Bug #21704)  File: manual.info, Node: news-5-1-36, Next: news-5-1-35, Prev: news-5-1-37, Up: news-5-1-x D.1.30 Changes in MySQL 5.1.36 (16 June 2009) --------------------------------------------- *Functionality added or changed:* * *Important Change*: *Replication*: Previously, incident log events were represented as comments in the output from *Note `mysqlbinlog': mysqlbinlog, making them effectively silent when playing back the binlog. (An incident log event represents an incident that could cause the contents of the database to change without that event being recorded in the binary log.) This meant that, if the SQL were applied to a server, it could potentially lead to the master and the slave having different data. To make it possible to handle incident log events without breaking applications that expect the previous behavior, the nonsense statement `RELOAD DATABASE' is added to the SQL output for that incident log event, which causes an error. To use this functionality currently requires hand editing of the dump file and handling of each case on an individual basis by a database administrator before applying the output to a server. (Bug #44442) * *Note `mysql_upgrade': mysql-upgrade. now displays a message indicating the connection parameters it uses when invoking *Note `mysqlcheck': mysqlcheck. (Bug #44638) * The time zone tables available at `http://dev.mysql.com/downloads/timezones.html' have been updated. These tables can be used on systems such as Windows or HP-UX that do not include zoneinfo files. (Bug #39923) * The `mysqltest' program now has a `move_file FROM_FILE TO_FILE' command for renaming files. This should be used in test cases rather than invoking an external command that might be platform specific. (Bug #39542) * The maximum value for `max_binlog_cache_size' has been increased from 2^32 - 1 to 2^64 - 1 (even on 32-bit platforms), which enables transactions 4GB and larger to be performed when binary logging is enabled. (Bug #10206) *Bugs fixed:* * *Performance*: The `InnoDB' adaptive hash latch is released (if held) for several potentially long-running operations. This improves throughput for other queries if the current query is removing a temporary table, changing a temporary table from memory to disk, using *Note `CREATE TABLE ... SELECT': create-table, or performing a `MyISAM' repair on a table used within a transaction. (Bug #32149) * *Security Fix*: The server crashed if an account with the `CREATE ROUTINE' privilege but not the `EXECUTE' privilege attempted to create a stored procedure. (Bug #44798) * *Security Fix*: The server crashed if an account without the proper privileges attempted to create a stored procedure. (Bug #44658) * *Security Fix*: Four potential format string vulnerabilities were fixed (discovered by the Veracode code analysis). (Bug #44166) * *Incompatible Change*: The server can load plugins under the control of startup options. For example, many storage engines can be built in pluggable form and loaded when the server starts. In the following descriptions, PLUGIN_NAME stands for a plugin name such as `innodb'. Previously, plugin options were handled like other boolean options (see *Note option-modifiers::). That is, any of these options enabled the plugin: --PLUGIN_NAME --PLUGIN_NAME=1 --enable-PLUGIN_NAME And these options disabled the plugin: --PLUGIN_NAME=0 --disable-PLUGIN_NAME --skip-PLUGIN_NAME However, use of a boolean option for plugin loading did not provide control over what to do if the plugin failed to start properly: Should the server exit, or start with the plugin disabled? The actual behavior has been that the server starts with the plugin disabled, which can be problematic. For example, if `InnoDB' fails to start, existing `InnoDB' tables become inaccessible, and attempts to create new `InnoDB' tables result in tables that use the default storage engine unless the `NO_ENGINE_SUBSTITUTION' SQL mode has been enabled to cause an error to occur instead. Now, there is a change in the options used to control plugin loading, such that they have a tristate format: * `--PLUGIN_NAME=OFF' Do not enable the plugin. * `--PLUGIN_NAME[=ON]' Enable the plugin. If plugin initialization fails, start the server anyway, but with the plugin disabled. Specifying the option as `--PLUGIN_NAME' without a value also enables the plugin. * `--PLUGIN_NAME=FORCE' Enable the plugin. If plugin initialization fails, do not start the server. In other words, force the server to run with the plugin or not at all. The values `OFF', `ON', and `FORCE' are not case sensitive. Suppose that `CSV' and `InnoDB' have been built as pluggable storage engines and that you want the server to load them at startup, subject to these conditions: The server is permitted to run if `CSV' initialization fails, but must require that `InnoDB' initialization succeed. To accomplish that, use these lines in an option file: [mysqld] csv=ON innodb=FORCE This change is incompatible with the previous implementation if you used options of the form `--PLUGIN_NAME=0' or `--PLUGIN_NAME=1', which should be changed to `--PLUGIN_NAME=OFF' or `--PLUGIN_NAME=ON', respectively. `--enable-PLUGIN_NAME' is still supported and is the same as `--PLUGIN_NAME=ON'. `--disable-PLUGIN_NAME' and `--skip-PLUGIN_NAME' are still supported and are the same as `--PLUGIN_NAME=OFF'. (Bug #19027) See also Bug #45336. * *Important Change*: *Replication*: *Note `BEGIN': commit, *Note `COMMIT': commit, and *Note `ROLLBACK': commit. statements are no longer affected by `--replicate-do-db' or `--replicate-ignore-db' rules. (Bug #43263) * *Partitioning*: Queries using `DISTINCT' on multiple columns or `GROUP BY' on multiple columns did not return correct results with partitioned tables. (Bug #44821) See also Bug #41136. * *Replication*: When using row-based logging, the length of an event for which the field metadata exceeded 255 bytes in size was incorrectly calculated. This could lead to corruption of the binary log, or cause the server to hang. (Bug #42749) See also Bug #44548, Bug #44672, Bug #44752. * *Replication*: The warning `Statement is not safe to log in statement format', issued in situations when it cannot be determined that a statement or other database event can be written reliably to the binary log using the statement-based format, has been changed to `Statement may not be safe to log in statement format'. (Bug #42415) * *Replication*: The `Query_log_event' used by replication to transfer a query to the slave has been refactored. `Query_log_event' also stores and sends the error code resulting from the execution since it, in some cases, is necessary to execute the statement on the slave as well, which should result in the same error code. The `Query_log_event' constructor previously worked out for itself the error code using a complex routine, the result of which was often set aside within the constructor itself. This was also involved with at least 2 known bugs relating to invalid errors, and taken as a clear sign that the constructor was not well-designed and needed to be re-written. (Bug #41948) See also Bug #37145. * *Replication*: When stopping and restarting the slave while it was replicating temporary tables, the slave server could crash or raise an assertion failure. This was due to the fact that, although temporary tables were saved between slave thread restarts, the reference to the thread being used (`table->in_use') was not being properly updated when restarting, continuing to reference the old thread instead of the new one. This issue affected statement-based replication only. (Bug #41725) * A separator was added between the time tag and the thread ID in the general query log file. (Bug #45387) * The combination of `MIN()' or `MAX()' in the select list with `WHERE' and `GROUP BY' clauses could lead to incorrect results. (Bug #45386) * Linker failures with `libmysqld' on VC++ 2008 were fixed. (Bug #45326) * Compiler warnings on Mac OS X were fixed. (Bug #45286) * Running a `SELECT' query over an `IBMDB2I' table using the `cp1250' character set would produce an error ibmdb2i error 2027: Error converting single-byte sort sequence to UCS-2 (Bug #45197) * Use of `ROUND()' on a *Note `LONGTEXT': blob. or *Note `LONGBLOB': blob. column of a derived table could cause a server crash. (Bug #45152) * *Note `DROP USER': drop-user. could fail to drop all privileges for an account if the `PAD_CHAR_TO_FULL_LENGTH' SQL mode was enabled. (Bug #45100) * `GROUP BY' on a `constant' (single-row) `InnoDB' table joined to other tables caused a server crash. (Bug #44886) * *Note `ALTER TABLE': alter-table. on a view crashed the server. (Bug #44860) * When using partitioning with the `IBMDB2I' storage engine, the engine could report that a valid character set was not supported. (Bug #44856) * Running queries on tables with the `IBMDB2I' storage engine using the `utf8' character would fail when using the 64-bit version of MySQL. (Bug #44811) * Index Merge followed by a filesort could result in a server crash if `sort_buffer_size' was not large enough for all sort keys. (Bug #44810) See also Bug #40974. * `UNCOMPRESSED_LENGTH()' returned a garbage result when passed a string shorter than 5 bytes. Now `UNCOMPRESSED_LENGTH()' returns `NULL' and generates a warning. (Bug #44796) * Several Valgrind warnings were silenced. (Bug #44774, Bug #44792) * Selecting `RAND(N)' function where N is a column of a `constant' table (table with a single row) failed with a `SIGFPE' signal. (Bug #44768) * The `PASSWORD()' and `OLD_PASSWORD()' functions could read memory outside of an internal buffer when used with *Note `BLOB': blob. arguments. (Bug #44767) * Conversion of a string to a different character set could use the same buffer for input and output, leading to incorrect results or warnings. (Bug #44743, Bug #44766) * *Note `mysqld_safe': mysqld-safe. could fail to find the `logger' program. (Bug #44736) * Code that optimized a read-only XA transaction failed to reset the XID once the transaction was no longer active. (Bug #44672) * A Valgrind warning related to transaction processing was silenced. (Bug #44664) * Some Perl scripts in AIX packages contained an incorrect path to the `perl' executable. (Bug #44643) * When creating tables using the `IBMDB2I' storage engine, the `RCDFMT' (record format) that would be applied to the corresponding files within the IBM i would be set according to the table name. During whole table operations, the name could get modified to a value inconsistent with the table name. In addition, the record format would be inconsistent compared to the file content. The `IBMDB2I' storage engine now adds an explicit `RCDFMT' clause to the `CREATE TABLE' statement passed down to the DB2 storage engine layer. (Bug #44610) * *Note `innochecksum': innochecksum. could incorrectly determine the input file name from the arguments. (Bug #44484) * Incorrect time was reported at the end of *Note `mysqldump': mysqldump. output. (Bug #44424) * Caching of `GROUP BY' expressions could lead to mismatches between compile-time and runtime calculations and cause a server crash. (Bug #44399) * Lettercase conversion in multibyte `cp932' or `sjis' character sequences could produce incorrect results. (Bug #44352) * `InnoDB' was missing `DB_ROLL_PTR' information in Table Monitor `COLUMNS' output. (Bug #44320) * Assertion failure could occur for duplicate-key errors in *Note `INSERT INTO ... SELECT': insert-select. statements. (Bug #44306) * Trying to use an unsupported character set on an `IBMDB2I' table would produce DB2 error 2501 or 2511. The error has been updated to produce Error 2504 (Character set is unsupported). (Bug #44232) * On 64-bit Windows systems, *Note `myisamchk': myisamchk. did not handle `key_buffer_size' values larger than 4GB. (Bug #43940) * For user-defined `utf8' collations, attempts to store values too long for a column could cause a server crash. (Bug #43827) * Invalidation of query cache entries due to table modifications could cause threads to hang inside the query cache with state `freeing items'. (Bug #43758) * *Note `EXPLAIN EXTENDED': explain. could crash for *Note `UNION': union. queries in which the last *Note `SELECT': select. was not parenthesized and included an `ORDER BY' clause. (Bug #43612) * Multiple-table updates for `InnoDB' tables could produce unexpected results. (Bug #43580) * If the client lost the connection to the MySQL server after *Note `mysql_stmt_prepare()': mysql-stmt-prepare, the first call to *Note `mysql_stmt_execute()': mysql-stmt-execute. returned an error (as expected) but consecutive calls to *Note `mysql_stmt_execute()': mysql-stmt-execute. or *Note `mysql_stmt_close()': mysql-stmt-close. crashed the client. (Bug #43560) * For `DELETE' statements with `ORDER BY VAR', where VAR was a global system variable with a `NULL' value, the server could crash. (Bug #42778) * Builds linked against OpenSSL had a memory leak in association with use of X509 certificates. (Bug #42158) * There was a race condition when changing `innodb_commit_concurrency' at runtime from zero to nonzero or from nonzero to zero. Now this variable cannot be changed at runtime from zero to nonzero or vice versa. The value can still be changed from one nonzero value to another. (Bug #42101) See also Bug #45749. * *Note `SELECT ... INTO @var': select. could produce values different from *Note `SELECT ...': select. without the `INTO' clause. (Bug #42009) * *Note `mysql_zap': mysql-zap. did not work on Mac OS X. (Bug #41883) * A crash occurred due to a race condition between the merge table and `table_cache' evictions. 00000001403C452F mysqld.exe!memcpy()[memcpy.asm:151] 00000001402A275F mysqld.exe!ha_myisammrg::info()[ha_myisammrg.cc:854] 00000001402A2471 mysqld.exe!ha_myisammrg::attach_children()[ha_myisammrg.cc:488] 00000001402A2788 mysqld.exe!ha_myisammrg::extra()[ha_myisammrg.cc:863] 000000014015FC5D mysqld.exe!attach_merge_children()[sql_base.cc:4135] 000000014016A4C1 mysqld.exe!open_tables()[sql_base.cc:4697] 000000014016A898 mysqld.exe!open_and_lock_tables_derived()[sql_base.cc:4956] 000000014018BB54 mysqld.exe!mysql_insert()[sql_insert.cc:613] 000000014019EDD3 mysqld.exe!mysql_execute_command()[sql_parse.cc:3066] 00000001401A2F06 mysqld.exe!mysql_parse()[sql_parse.cc:5791] 00000001401A3C1A mysqld.exe!dispatch_command()[sql_parse.cc:1202] 00000001401A4CD7 mysqld.exe!do_command()[sql_parse.cc:857] 0000000140246327 mysqld.exe!handle_one_connection()[sql_connect.cc:1115] 00000001402B82C5 mysqld.exe!pthread_start()[my_winthread.c:85] 00000001403CAC37 mysqld.exe!_callthreadstart()[thread.c:295] 00000001403CAD05 mysqld.exe!_threadstart()[thread.c:275] 0000000077D6B69A kernel32.dll!BaseThreadStart() Trying to get some variables. Some pointers may be invalid and cause the dump to abort... (Bug #41212) * Shared-memory connections did not work in Vista if *Note `mysqld': mysqld. was started from the command line. (Bug #41190) * For views created with a column list clause, column aliases were not substituted when selecting through the view using a `HAVING' clause. (Bug #40825) * A multiple-table *Note `DELETE': delete. involving a table self-join could cause a server crash. (Bug #39918) * Creating an `InnoDB' table with a comment containing a `'#'' character caused foreign key constraints to be omitted. (Bug #39793) * *Note `ALTER TABLE': alter-table. neglected to preserve `ROW_FORMAT' information from the original table, which could cause subsequent *Note `ALTER TABLE': alter-table. and *Note `OPTIMIZE TABLE': optimize-table. statements to lose the row format for `InnoDB' tables. (Bug #39200) * The *Note `mysql': mysql. option `--ignore-spaces' was nonfunctional. (Bug #39101) * If a query was such as to produce the error `1054 Unknown column '...' in 'field list'', using *Note `EXPLAIN EXTENDED': explain. with the query could cause a server crash. (Bug #37362) * In the *Note `mysql': mysql. client, using a default character set of `binary' caused internal commands such as `DELIMITER' to become case sensitive. (Bug #37268) * *Note `mysqldump --tab': mysqldump. dumped triggers to `stdout' rather than to the `.sql' file for the corresponding table. (Bug #34861) * If the `MYSQL_HISTFILE' environment variable was set to `/dev/null', the *Note `mysql': mysql. client overwrote the `/dev/null' device file as a normal file. (Bug #34224) * *Note `mysqld_safe': mysqld-safe. mishandled certain parameters if they contained spaces. (Bug #33685) * *Note `mysqladmin kill': mysqladmin. did not work for thread IDs larger than 32 bits. (Bug #32457) * Several client programs failed to interpret `--skip-password' as `send no password.' (Bug #28479) * Output from *Note `mysql --html': mysql. did not encode the `<', `>', or `&' characters. (Bug #27884) * *Note `mysql_convert_table_format': mysql-convert-table-format. did not prevent conversion of tables to `MEMORY' or `BLACKHOLE' tables, which could result in data loss. (Bug #27149)  File: manual.info, Node: news-5-1-35, Next: news-5-1-34sp1, Prev: news-5-1-36, Up: news-5-1-x D.1.31 Changes in MySQL 5.1.35 (13 May 2009) -------------------------------------------- *Windows Notes:* * This release of MySQL has two known outstanding issues for Windows: * The `.msi' installer does not detect an existing `root' password on the initial configuration attempt. To work around this, install and configure MySQL as normal, but skip any changes to security. (There is a check box that enables this on the security screen of the configuration wizard.) Then check your settings: * If the old `root' password and security settings are okay, you are done and can proceed to use MySQL. * Otherwise, reconfigure with the wizard and make any changes on the second configuration attempt. The wizard will properly prompt for the existing `root' password and permit changes to be made. This issue has been filed as Bug#45200 for correction in a future release. * The Windows configuration wizard permits changes to `InnoDB' settings during a reconfiguration operation. For an upgrade, this may cause difficulties. To work around this, use one of the following alternatives: * Do not change `InnoDB' settings. * Copy files from the old `InnoDB' location to the new one. This issue has been filed as Bug#45201 for correction in a future release. *Bugs fixed:* * *Performance*: *Note `InnoDB': innodb-storage-engine. uses random numbers to generate dives into indexes for calculating index cardinality. However, under certain conditions, the algorithm did not generate random numbers, so *Note `ANALYZE TABLE': analyze-table. did not update cardinality estimates properly. A new algorithm has been introduced with better randomization properties, together with a system variable, `innodb_use_legacy_cardinality_algorithm', that controls which algorithm to use. The default value of the variable is 1 (`ON'), to use the original algorithm for compatibility with existing applications. The variable can be set to 0 (`OFF') to use the new algorithm with improved randomness. (Bug #43660) * *Performance*: If the character set for a column being compared was neither the default server character set nor `latin1', `InnoDB' was slower than necessary due to excessive contention for a character set mutex. As a workaround for earlier versions, set the default server character set to the character set other than `latin1' that is most often used in indexed columns. (Bug #42649) * *Important Change*: *Replication*: The transactional behavior of *Note `STOP SLAVE': stop-slave. has changed. Formerly, it took effect immediately, even inside a transaction; now, it waits until the current replication event group (if any) has finished executing, or until the user issues a *Note `KILL QUERY': kill. or *Note `KILL CONNECTION': kill. statement. This was done to solve the problem encountered when replication was stopped while a nontransactional slave was replicating a transaction on the master. (It was impossible to roll back a mixed-engines transaction when one of the engines was nontransactional, which meant that the slave could not safely re-apply any transaction that had been interrupted by *Note `STOP SLAVE': stop-slave.) (Bug #319, Bug #38205) See also Bug #43217. * *Partitioning*: When a value was equal to a `PARTITION ... VALUES LESS THAN (VALUE)' value other than `MAXVALUE', the corresponding partition was not pruned. (Bug #42944) * *Replication*: Unrelated errors occurring during the execution of *Note `RESET SLAVE': reset-slave. could cause the slave to crash. (Bug #44179) * *Replication*: The `--slave-skip-errors' option had no effect when using row-based logging format. (Bug #39393) * *Replication*: The following errors were not correctly reported: * Failures during slave thread initialization * Failures while initializing the relay log position (immediately following the starting of the slave thread) * Failures while processing queries passed through the `--init_slave' option. Information about these types of failures can now be found in the output of *Note `SHOW SLAVE STATUS': show. (Bug #38197) * *Replication*: Killing the thread executing a DDL statement, after it had finished its execution but before it had written the binlog event, caused the error code in the binlog event to be set (incorrectly) to ER_SERVER_SHUTDOWN or ER_QUERY_INTERRUPTED, which caused replication to fail. (Bug #37145) See also Bug #27571, Bug #22725. * *Replication*: Column aliases used inside subqueries were ignored in the binary log. (Bug #35515) * Valgrind warnings for the `DECODE()', `ENCRYPT()', and `FIND_IN_SET()' functions were corrected. (Bug #44358, Bug #44365, Bug #44367) * On Windows, entries for `build-vs9.bat' and `build-vs9_x64.bat' were missing in `win/Makefile.am'. (Bug #44353) * Incomplete cleanup of `JOIN_TAB::select' during the filesort of rows for a `GROUP BY' clause inside a subquery caused a server crash. (Bug #44290) * Not all lock types had proper descriptive strings, resulting in garbage output from *Note `mysqladmin debug': mysqladmin. (Bug #44164) * Use of *Note `HANDLER': handler. statements with `INFORMATION_SCHEMA' tables caused a server crash. Now *Note `HANDLER': handler. is prohibited with such tables. (Bug #44151) * MySQL Server permitted the creation of a merge table based on views but crashed when attempts were made to read from that table. The following example demonstrates this: #Create a test table CREATE TABLE tmp (id int, c char(2)); #Create two VIEWs upon it CREATE VIEW v1 AS SELECT * FROM tmp; CREATE VIEW v2 AS SELECT * FROM tmp; #Finally create a MERGE table upon the VIEWs CREATE TABLE merge (id int, c char(2)) ENGINE=MERGE UNION(v1, v2); #Reading from the merge table lead to a crash SELECT * FROM merge; The final line of the code generated the crash. (Bug #44040) * Some schema names longer than 8 characters were not supported by `IBMDB2I'. The engine has been updated to permit digits and underscore characters to be used in names longer than 8 characters. (Bug #44025) * In some circumstances, when a table is created with the `IBMDB2I' engine, the `CREATE TABLE' statement will return successfully but the table will not exist. (Bug #44022) * The `ucs2_swedish_ci' and `utf8_swedish_ci' collations did not work with indexes using the `IBMDB2I' storage engine. Support is now provided for MySQL when running on IBM i 6.1 or higher. (Bug #44020) * Invoking *Note `SHOW TABLE STATUS': show-table-status. from within a stored procedure could cause a `Packets out of order' error. (Bug #43962) * *Note `myisamchk': myisamchk. could display a negative `Max keyfile length' value. (Bug #43950) * On 64-bit systems, a `key_buffer_size' value larger than 4GB could couse `MyISAM' index corruption. (Bug #43932) * *Note `mysqld_multi': mysqld-multi. incorrectly passed `--no-defaults' to *Note `mysqld_safe': mysqld-safe. (Bug #43876) * *Note `SHOW VARIABLES': show-variables. did not properly display the value of `slave_skip_errors'. (Bug #43835) * On Windows, a server crash occurred for attempts to insert a floating-point value into a *Note `CHAR': char. column with a maximum length less than the converted floating-point value length. (Bug #43833) * Incorrect initialization of `MyISAM' table indexes could cause incorrect query results. (Bug #43737) * `libmysqld' crashed when it was reinitialized. (Bug #43706, Bug #44091) * *Note `UNION': union. of floating-point numbers did unnecessary rounding. (Bug #43432) * *Note `ALTER DATABASE ... UPGRADE DATA DIRECTORY NAME': alter-database. failed when the database contained views. (Bug #43385) * Certain statements might open a table and then wait for an impending global read lock without noticing whether they hold a table being waiting for by the global read lock, causing a hang. Affected statements are *Note `SELECT ... FOR UPDATE': select, *Note `LOCK TABLES ... WRITE': lock-tables, *Note `TRUNCATE TABLE': truncate-table, and *Note `LOAD DATA INFILE': load-data. (Bug #43230) * Using an XML function such as `ExtractValue()' more than once in a single query could produce erroneous results. (Bug #43183) See also Bug #43937. * Full-text prefix searches could hang the connection and cause 100% CPU consumption. (Bug #42907) * Incorrect elevation of warning messages to error messages for unsafe statements caused a server crash. (Bug #42640) * *Note `CHECK TABLE': check-table. suggested use of *Note `REPAIR TABLE': repair-table. for corrupt tables for storage engines not supported by *Note `REPAIR TABLE': repair-table. Now *Note `CHECK TABLE': check-table. suggests that the user dump and reload the table. (Bug #42563) * Compressing a table with the *Note `myisampack': myisampack. utility caused the server to produce Valgrind warnings when it opened the table. (Bug #41541) * For a `MyISAM' table with `DELAY_KEY_WRITE' enabled, the index file could be corrupted without the table being marked as crashed if the server was killed. (Bug #41330) * For some queries, an equality propagation problem could cause `a = b' and `b = a' to be handled differently. (Bug #40925) * Killing an *Note `INSERT ... SELECT': insert-select. statement for a `MyISAM' table could cause table corruption if the table had indexes. (Bug #40827) * A multiple-table *Note `DELETE IGNORE': delete. statement involving a foreign key constraint caused an assertion failure. (Bug #40127) * Multiple-table *Note `UPDATE': update. statements did not properly activate triggers. (Bug #39953) * The *Note `mysql_setpermission': mysql-setpermission. operation for removing database privileges removed global privileges instead. (Bug #39852) * A stored routine contain a C-style comment could not be dumped and reloaded. (Bug #39559) * In an *Note `UPDATE': update. or *Note `DELETE': delete. through a secondary index, `InnoDB' did not store the cursor position. This made `InnoDB' crash in semi-consistent read while attempting to unlock a nonmatching record. (Bug #39320) * The functions listed in *Note gis-mysql-specific-functions::, previously accepted WKB arguments and returned WKB values. They now accept WKB or geometry arguments and return geometry values. The functions listed in *Note gis-wkb-functions::, previously accepted WKB arguments and returned geometry values. They now accept WKB or geometry arguments and return geometry values. (Bug #38990) * On Windows, running the server with `myisam_use_mmap' enabled caused `MyISAM' table corruption. (Bug #38848) * *Note `CHECK TABLE': check-table. did not properly check whether `MyISAM' tables created by servers from MySQL 4.0 or older needed to be upgraded. This could cause problems upgrading to MySQL 5.1 or higher. (Bug #37631) * An *Note `UPDATE': update. statement that updated a column using the same `DES_ENCRYPT()' value for each row actually updated different rows with different values. (Bug #35087) * For shared-memory connections, the read and write methods did not properly handle asynchronous close events, which could lead to the client locking up waiting for a server response. For example, a call to *Note `mysql_real_query()': mysql-real-query. would block forever on the client side if the executed statement was aborted on the server side. Thanks to Armin Scho"ffmann for the bug report and patch. (Bug #33899) * *Note `CHECKSUM TABLE': checksum-table. was not killable with *Note `KILL QUERY': kill. (Bug #33146) * *Note `myisamchk': myisamchk. and *Note `myisampack': myisampack. were not being linked with the library that enabled support for `*' filename pattern expansion. (Bug #29248) * For `InnoDB' tables that have their own `.ibd' tablespace file, a superfluous `ibuf cursor restoration fails!' message could be written to the error log. This warning has been suppressed. (Bug #27276) * *Note `COMMIT': commit. did not delete savepoints if there were no changes in the transaction. (Bug #26288) * Several memory allocation functions were not being checked for out-of-memory return values. (Bug #25058)  File: manual.info, Node: news-5-1-34sp1, Next: news-5-1-34, Prev: news-5-1-35, Up: news-5-1-x D.1.32 Release Notes for MySQL Enterprise 5.1.34sp1 [QSP] (25 June 2009) ------------------------------------------------------------------------ This is a _Service Pack_ release of the MySQL Enterprise Server 5.1. This section documents all changes and bugfixes that have been applied since the last MySQL Enterprise Server release (5.1.34). *Note*: The fix for Bug#40974 in MySQL 5.1.31 caused the regression problem reported in Bug#44810. Users for whom stability is of utmost priority should note that 5.1.34sp1 is affected by this problem because Bug#44810 is not fixed until MySQL 5.1.36. If you would like to receive more fine-grained and personalized _update alerts_ about fixes that are relevant to the version and features you use, please consider subscribing to _MySQL Enterprise_ (a commercial MySQL offering). For more details please see http://www.mysql.com/products/enterprise/advisors.html. *Bugs fixed:* * Incomplete cleanup of `JOIN_TAB::select' during the filesort of rows for a `GROUP BY' clause inside a subquery caused a server crash. (Bug #44290) * Use of *Note `HANDLER': handler. statements with `INFORMATION_SCHEMA' tables caused a server crash. Now *Note `HANDLER': handler. is prohibited with such tables. (Bug #44151) * On 64-bit systems, a `key_buffer_size' value larger than 4GB could couse `MyISAM' index corruption. (Bug #43932) * On Windows, a server crash occurred for attempts to insert a floating-point value into a *Note `CHAR': char. column with a maximum length less than the converted floating-point value length. (Bug #43833) * `libmysqld' crashed when it was reinitialized. (Bug #43706, Bug #44091) * Certain statements might open a table and then wait for an impending global read lock without noticing whether they hold a table being waiting for by the global read lock, causing a hang. Affected statements are *Note `SELECT ... FOR UPDATE': select, *Note `LOCK TABLES ... WRITE': lock-tables, *Note `TRUNCATE TABLE': truncate-table, and *Note `LOAD DATA INFILE': load-data. (Bug #43230) * Using an XML function such as `ExtractValue()' more than once in a single query could produce erroneous results. (Bug #43183) See also Bug #43937. * Incorrect elevation of warning messages to error messages for unsafe statements caused a server crash. (Bug #42640) * In an *Note `UPDATE': update. or *Note `DELETE': delete. through a secondary index, `InnoDB' did not store the cursor position. This made `InnoDB' crash in semi-consistent read while attempting to unlock a nonmatching record. (Bug #39320) * The functions listed in *Note gis-mysql-specific-functions::, previously accepted WKB arguments and returned WKB values. They now accept WKB or geometry arguments and return geometry values. The functions listed in *Note gis-wkb-functions::, previously accepted WKB arguments and returned geometry values. They now accept WKB or geometry arguments and return geometry values. (Bug #38990)  File: manual.info, Node: news-5-1-34, Next: news-5-1-33, Prev: news-5-1-34sp1, Up: news-5-1-x D.1.33 Changes in MySQL 5.1.34 (02 April 2009) ---------------------------------------------- *RPM Notes* * Support Ending for AIX 5.2: Per the http://www.mysql.com/about/legal/lifecycle/ regarding ending support for OS versions that have reached vendor end of life, we plan to discontinue building or supporting MySQL binaries for AIX 5.2 as of April 30, 2009. This release of MySQL 5.1 (5.1.34) is the last MySQL 5.1 release with support for AIX 5.2. For more information, see the March 24, 2009 note at MySQL Product Support EOL Announcements (http://dev.mysql.com/support/eol-notice.html). *Functionality added or changed:* * The `optimizer_switch' system variable is now available to control optimizations that can be switched on and off. See *Note switchable-optimizations::. *Bugs fixed:* * *Replication*: *Important Note*: Binary logging with `--binlog-format=ROW' failed when a change to be logged included more than 251 columns. This issue was not known to occur with mixed-format or statement-based logging. (Bug #42977) See also Bug #42914. * *Replication*: Assigning an invalid directory for the `--slave-load-tmpdir' caused the replication slave to crash. (Bug #42861) * *Replication*: The `mysql.procs_priv' system table was not replicated. (Bug #42217) * *Replication*: An *Note `INSERT DELAYED': insert. into a *Note `TIMESTAMP': datetime. column issued concurrently with an insert on the same column not using `DELAYED', but applied after the other insert, was logged using the same timestamp as generated by the other (non-`DELAYED') insert. (Bug #41719) * *Replication*: The `MIXED' binary logging format did not switch to row-based mode for statements containing the `LOAD_FILE()' function. (Bug #39701) * *Replication*: When the server SQL mode included `IGNORE_SPACE', statement-based replication of *Note `LOAD DATA INFILE ... INTO TBL_NAME': load-data. failed because the statement was read incorrectly from the binary log; a trailing space was omitted, causing the statement to fail with a syntax error when run on the slave. (Bug #22504) See also Bug #43746. * An attempt by a user who did not have the `SUPER' privilege to kill a system thread could cause a server crash. (Bug #43748) * On Windows, incorrectly specified link dependencies in `CMakeLists.txt' resulted in link errors for `mysql_embedded', `mysqltest_embedded', and `mysql_client_test_embedded'. (Bug #43715) * *Note `mysql': mysql. crashed if a request for the current database name returned an empty result, such as after the client has executed a preceding `SET sql_select_limit=0' statement. (Bug #43254) * If the value of the `version_comment' system variable was too long, the *Note `mysql': mysql. client displayed a truncated startup message. (Bug #43153) * Queries of the following form returned an empty result: SELECT ... WHERE ... (COL=COL AND COL=COL) OR ... (FALSE EXPRESSION) (Bug #42957) * The `strings/CHARSET_INFO.txt' file was not included in source distributions. (Bug #42937) * A dangling pointer in `mysys/my_error.c' could lead to client crashes. (Bug #42675) * Passing an unknown time zone specification to `CONVERT_TZ()' resulted in a memory leak. (Bug #42502) * The MySQL Instance Configuration Wizard would fail to start correctly on Windows Vista. (Bug #42386) * With more than two arguments, `LEAST()', `GREATEST()', and `CASE' could unnecessarily return `Illegal mix of collations' errors. (Bug #41627) * The *Note `mysql': mysql. client could misinterpret its input if a line was longer than an internal buffer. (Bug #41486) * In the `help' command output displayed by *Note `mysql': mysql, the description for the `\c' (`clear') command was misleading. (Bug #41268) * The `load_defaults()', `my_search_option_files()' and `my_print_default_files()' functions in the C client library were subject to a race condition in multi-threaded operation. (Bug #40552) * If `--basedir' was specified, *Note `mysqld_safe': mysqld-safe. did not use it when attempting to locate *Note `my_print_defaults': my-print-defaults. (Bug #39326) * When running the MySQL Instance Configuration Wizard in command-line only mode, the service name would be ignored (effectively creating all instances with the default `MySQL' service name), irrespective of the name specified on the command line. However, the wizard would attempt to start the service with the specified name, and would fail. (Bug #38379) * When MySQL was configured with the `--with-max-indexes=128' option, *Note `mysqld': mysqld. crashed. (Bug #36751) * Setting the `join_buffer_size' variable to its minimum value produced spurious warnings. (Bug #36446) * The use of `NAME_CONST()' can result in a problem for *Note `CREATE TABLE ... SELECT': create-table. statements when the source column expressions refer to local variables. Converting these references to `NAME_CONST()' expressions can result in column names that are different on the master and slave servers, or names that are too long to be legal column identifiers. A workaround is to supply aliases for columns that refer to local variables. Now a warning is issued in such cases that indicate possible problems. (Bug #35383) * An attempt to check or repair an *Note `ARCHIVE': archive-storage-engine. table that had been subjected to a server crash returned a 144 internal error. The data appeared to be irrecoverable. (Bug #32880) * The `Time' column for *Note `SHOW PROCESSLIST': show-processlist. output and the value of the `TIME' column of the *Note `INFORMATION_SCHEMA.PROCESSLIST': processlist-table. table now can have negative values. Previously, the column was unsigned and negative values were displayed incorrectly as large positive values. Negative values can occur if a thread alters the time into the future with *Note `SET TIMESTAMP = VALUE': set-option. or the thread is executing on a slave and processing events from a master that has its clock set ahead of the slave. (Bug #22047) * Restoring a *Note `mysqldump': mysqldump. dump file containing `FEDERATED' tables failed because the file contained the data for the table. Now only the table definition is dumped (because the data is located elsewhere). (Bug #21360)  File: manual.info, Node: news-5-1-33, Next: news-5-1-32, Prev: news-5-1-34, Up: news-5-1-x D.1.34 Changes in MySQL 5.1.33 (13 March 2009) ---------------------------------------------- *RPM Notes* * Support Ending for AIX 5.2: Per the http://www.mysql.com/about/legal/lifecycle/ regarding ending support for OS versions that have reached vendor end of life, we plan to discontinue building or supporting MySQL binaries for AIX 5.2 as of April 30, 2009. The next release of MySQL 5.1 (5.1.34) will be the last MySQL 5.1 release with support for AIX 5.2. For more information, see the March 24, 2009 note at MySQL Product Support EOL Announcements (http://dev.mysql.com/support/eol-notice.html). *Functionality added or changed:* * *Performance*: The query cache now checks whether a *Note `SELECT': select. statement begins with `SQL_NO_CACHE' to determine whether it can skip checking for the query result in the query cache. This is not supported when `SQL_NO_CACHE' occurs within a comment. (Bug #37416) * `mysql-test-run.pl' now supports an `--experimental=FILE_NAME' option. It enables you to specify a file that contains a list of test cases that should be displayed with the `[ exp-fail ]' code rather than `[ fail ]' if they fail. (Bug #42888) * The MD5 algorithm now uses the Xfree implementation. (Bug #42434) *Bugs fixed:* * *Partitioning*: A duplicate key error raised when inserting into a partitioned table using a different error code from that returned by such an error raised when inserting into a table that was not partitioned. (Bug #38719) See also Bug #28842. * *Partitioning*: Several error messages relating to partitioned tables were incorrect or missing. (Bug #36001) * *Replication*: When `binlog_format' was set to `STATEMENT', a statement unsafe for statement-based logging caused an error or warning to be issued even if `sql_log_bin' was set to 0. (Bug #41980) * *Replication*: When using `MIXED' replication format and temporary tables were created in statement-based mode, but a later operation in the same session caused a switch to row-based mode, the temporary tables were not dropped on the slave at the end of the session. (Bug #40013) See also Bug #43046. This regression was introduced by Bug #20499. * *Replication*: When using the `MIXED' replication format, *Note `UPDATE': update. and *Note `DELETE': delete. statements that searched for rows where part of the key had nullable *Note `BIT': numeric-types. columns failed. This occurred because operations that inserted the data were replicated as statements, but *Note `UPDATE': update. and *Note `DELETE': delete. statements affecting the same data were replicated using row-based format. This issue did not occur when using statement-based replication (only) or row-based replication (only). (Bug #39753) See also Bug #39648. * *Replication*: The server SQL mode in effect when a stored procedure was created was not retained in the binary log. This could cause a *Note `CREATE PROCEDURE': create-procedure. statement that succeeded on the master to fail on the slave. This issue was first noticed when a stored procedure was created when `ANSI_QUOTES' was in effect on the master, but could possibly cause failed *Note `CREATE PROCEDURE': create-procedure. statements and other problems on the slave when using other server SQL modes as well. (Bug #39526) * *Replication*: If `--secure-file-priv' was set on the slave, it was unable to execute *Note `LOAD DATA INFILE': load-data. statements sent from the master when using mixed-format or statement-based replication. As a result of this fix, this security restriction is now ignored on the slave in such cases; instead the slave checks whether the files were created and should be read by the slave in its `--slave-load-tmpdir'. (Bug #38174) * *Replication*: Server IDs greater than 2147483647 (2^32 - 1) were represented by negative numbers in the binary log. (Bug #37313) * *Replication*: When its disk becomes full, a replication slave may wait while writing the binary log, relay log or *Note `MyISAM': myisam-storage-engine. tables, continuing after space has been made available. The error message provided in such cases was not clear about the frequency with which checking for free space is done (once every 60 seconds), and how long the server waits after space has been freed before continuing (also 60 seconds); this caused users to think that the server had hung. These issues have been addressed by making the error message clearer, and dividing it into two separate messages: 1. The error message `Disk is full writing 'FILENAME' (Errcode: ERROR_CODE). Waiting for someone to free space... (Expect up to 60 secs delay for server to continue after freeing disk space)' is printed only once. 2. The warning `Retry in 60 secs, Message reprinted in 600 secs' is printed once every for every 10 times that the check for free space is made; that is, the check is performed once each 60 seconds, but the reminder that space needs to be freed is printed only once every 10 minutes (600 seconds). (Bug #22082) * *Replication*: The statements *Note `DROP PROCEDURE IF EXISTS': drop-procedure. and *Note `DROP FUNCTION IF EXISTS': drop-function. were not written to the binary log if the procedure or function to be dropped did not exist. (Bug #13684) See also Bug #25705. * The IBM DB2i storage engine has been added to this release for the IBM i Series platform. For more information, see *Note se-db2::. (Bug #44217) * On 64-bit debug builds, code in `safemalloc' resulted in errors due to use of a 32-bit value for 64-bit allocations. (Bug #43885) * `make distcheck' failed to properly handle subdirectories of `storage/ndb'. (Bug #43614) * Use of `USE INDEX' hints could cause *Note `EXPLAIN EXTENDED': explain. to crash. (Bug #43354) * For `InnoDB' tables, overflow in an `AUTO_INCREMENT' column could cause a server crash. (Bug #43203) * On 32-bit Windows, *Note `mysqld': mysqld. could not use large buffers due to a 2GB user mode address limit. (Bug #43082) * `stderr' should be unbuffered, but when the server redirected `stderr' to a file, it became buffered. (Bug #42790) * The `DATA_TYPE' column of the *Note `INFORMATION_SCHEMA.COLUMNS': columns-table. table displayed the `UNSIGNED' attribute for floating-point data types. (The column should contain only the data type name.) (Bug #42758) * For `InnoDB' tables, spurious duplicate-key errors could occur when inserting into an `AUTO_INCREMENT' column. (Bug #42714) * *Note `mysqldump': mysqldump. included views that were excluded with the `--ignore-table' option. (Bug #42635) * An earlier bug fix resulted in the problem that the `InnoDB' plugin could not be used with a server that was compiled with the built-in `InnoDB'. To handle this two changes were made: * The server now supports an `--ignore-builtin-innodb' option that causes the server to behave as if the built-in `InnoDB' is not present. This option causes other `InnoDB' options not to be recognized. * For the *Note `INSTALL PLUGIN': install-plugin. statement, the server reads option (`my.cnf') files just as during server startup. This enables the plugin to pick up any relevant options from those files. Consequently, a plugin no longer is started with each option set to its default value. Because of this change, it is possible to add plugin options to an option file even before loading a plugin (if the `loose' prefix is used). It is also possible to uninstall a plugin, edit `my.cnf', and install the plugin again. Restarting the plugin this way enables it to the new option values without a server restart. *Note*: `InnoDB' Plugin versions 1.0.4 and higher will take advantage of this bug fix. Although the `InnoDB' Plugin is source code compatible with multiple MySQL releases, a given binary `InnoDB' Plugin can be used only with a specific MySQL release. When `InnoDB' Plugin 1.0.4 is released, it is expected to be compiled for MySQL 5.1.34. For 5.1.33, you can use `InnoDB' Plugin 1.0.3, but you must build from source. (Bug #42610) This regression was introduced by Bug #29263. * With the `ONLY_FULL_GROUP_BY' SQL mode enabled, some legal queries failed. (Bug #42567) * Tables could enter open table cache for a thread without being properly cleaned up, leading to a server crash. (Bug #42419) * For `InnoDB' tables, inserting into floating-point `AUTO_INCREMENT' columns failed. (Bug #42400) * The `InnoDB' `btr_search_drop_page_hash_when_freed()' function had a race condition. (Bug #42279) * For `InnoDB' tables, there was a race condition for *Note `ALTER TABLE': alter-table, *Note `OPTIMIZE TABLE': optimize-table, *Note `CREATE INDEX': create-index, and *Note `DROP INDEX': drop-index. operations when periodically checking whether table copying can be committed. (Bug #42152) * Parsing of the optional microsecond component of *Note `DATETIME': datetime. values did not fail gracefully when that component width was larger than the permitted six places. (Bug #42146) * In `InnoDB' recovery after a server crash, table lookup could fail and corrupt the data dictionary cache. (Bug #42075) * *Note `mysqldumpslow': mysqldumpslow. parsed the `--debug' and `--verbose' options incorrectly. (Bug #42027) * Queries that used the loose index scan access method could return no rows. (Bug #41610) * In `InnoDB' recovery after a server crash, rollback of a transaction that updated a column from `NULL' to `NULL' could cause another crash. (Bug #41571) * The error message for a too-long column comment was `Unknown error' rather than a more appropriate message. (Bug #41465) * Use of `SELECT *' permitted users with rights to only some columns of a view to access all columns. (Bug #41354) * If the tables underlying a *Note `MERGE': merge-storage-engine. table had a primary key but the *Note `MERGE': merge-storage-engine. table itself did not, inserting a duplicate row into the *Note `MERGE': merge-storage-engine. table caused a server crash. (Bug #41305) * The server did not robustly handle problems hang if a table opened with *Note `HANDLER': handler. needed to be re-opened because it had been altered to use a different storage engine that does not support *Note `HANDLER': handler. The server also failed to set an error if the re-open attempt failed. These problems could cause the server to crash or hang. (Bug #41110, Bug #41112) * *Note `SELECT': select. statements executed concurrently with *Note `INSERT': insert. statements for a `MyISAM' table could cause incorrect results to be returned from the query cache. (Bug #41098) * For prepared statements, multibyte character sets were not taking into account when calculating `max_length' for string values and *Note `mysql_stmt_fetch()': mysql-stmt-fetch. could return truncated strings. (Bug #41078) * Deprecation warnings that referred to MySQL 5.2 were changed to refer to MySQL 6.0. (Bug #41077) * For user-defined variables in a query result, incorrect length values were returned in the result metadata. (Bug #41030) * On Windows, starting the server with an invalid value for `innodb_flush_method' caused a crash. (Bug #40757) * MySQL 5.1 crashed with index merge algorithm and merge tables. A query in the MyISAM merge table caused a crash if the index merge algorithm was being used. (Bug #40675) * With strict SQL mode enabled, setting a system variable to an out-of-bounds value caused an assertion failure. (Bug #40657) * Table temporary scans were slower than necessary due to use of mmap rather than caching, even with the `myisam_use_mmap' system variable disabled. (Bug #40634) * For a view that references a table in another database, *Note `mysqldump': mysqldump. wrote the view name qualified with the current database name. This makes it impossible to reload the dump file into a different database. (Bug #40345) * On platforms where long and pointer variables have different sizes, `MyISAM' could copy key statistics incorrectly, resulting in a server crash or incorrect cardinality values. (Bug #40321) * *Note `DELETE': delete. tried to acquire write (not read) locks for tables accessed within a subquery of the `WHERE' clause. (Bug #39843) * *Note `perror': perror. did not produce correct output for error codes 153 to 163. (Bug #39370) * Several functions in `libmysqld' called `exit()' when an error occurred rather than returning an error to the caller. (Bug #39289) * The `innodb_log_arch_dir' system variable is no longer available but was present in some of the sample option files included with MySQL distributions (such as `my-huge.cnf'). The line was present as a comment but uncommenting it would cause server startup failure so the line has been removed. (Bug #38249) * Setting a savepoint with the same name as an existing savepoint incorrectly deleted any other savepoints that had been set in the meantime. For example, setting savepoints named `a', `b', `c', `b' resulted in savepoints `a', `b', rather than the correct savepoints `a', `c', `b'. (Bug #38187) * `--help' output for *Note `myisamchk': myisamchk. did not list the `--HELP' option. (Bug #38103) * Comparisons between row constructors, such as `(a, b) = (c, d)' resulted in unnecessary `Illegal mix of collations' errors for string columns. (Bug #37601) * If a user created a view that referenced tables for which the user had disjoint privileges, an assertion failure occurred. (Bug #37191) * An argument to the `MATCH()' function that was an alias for an expression other than a column name caused a server crash. (Bug #36737) * The `event', `general_log', and `slow_log' tables in the `mysql' database store `server_id' values, but did not use an `UNSIGNED' column and thus were not able to store the full range of ID values. (Bug #36540) * On Windows, the `_PC' macro in `my_global.h' was causing problems for modern compilers. It has been removed because it is no longer used. (Bug #34309) * For *Note `DROP FUNCTION': drop-function. with names that were qualified with a database name, the database name was handled in case-sensitive fashion even with `lower_case_table_names' set to 1. (Bug #33813) * *Note `mysqldump --compatible=mysql40': mysqldump. emitted statements referring to the `character_set_client' system variable, which is unknown before MySQL 4.1. Now the statements are enclosed in version-specific comments. (Bug #33550) * Detection by `configure' of several functions such as `setsockopt()', `bind()', `sched_yield()', and `gtty()' could fail. (Bug #31506) * Use of MBR spatial functions such as `MBRTouches()' with columns of `InnoDB' tables caused a server crash rather than an error. (Bug #31435) * The *Note `mysql': mysql. client mishandled input parsing if a `delimiter' command was not first on the line. (Bug #31060) * *Note `SHOW PRIVILEGES': show-privileges. listed the `CREATE ROUTINE' privilege as having a context of `Functions,Procedures', but it is a database-level privilege. (Bug #30305) * *Note `mysqld --help': mysqld. did not work as `root'. (Bug #30261) * *Note `CHECK TABLE': check-table, *Note `REPAIR TABLE': repair-table, *Note `ANALYZE TABLE': analyze-table, and *Note `OPTIMIZE TABLE': optimize-table. erroneously reported a table to be corrupt if the table did not exist or the statement was terminated with *Note `KILL': kill. (Bug #29458) * *Note `SHOW TABLE STATUS': show-table-status. could fail to produce output for tables with non-ASCII characters in their name. (Bug #25830) * Allocation of stack space for error messages could be too small on HP-UX, leading to stack overflow crashes. (Bug #21476) * Floating-point numbers could be handled with different numbers of digits depending on whether the text or prepared-statement protocol was used. (Bug #21205) * Incorrect length metadata could be returned for `LONG TEXT' columns when a multibyte server character set was used. (Bug #19829) * `ROUND()' sometimes returned different results on different platforms. (Bug #15936)  File: manual.info, Node: news-5-1-32, Next: news-5-1-31sp1, Prev: news-5-1-33, Up: news-5-1-x D.1.35 Changes in MySQL 5.1.32 (14 February 2009) ------------------------------------------------- *Functionality added or changed:* * The `libedit' library was upgraded to version 2.11. (Bug #42433) *Bugs fixed:* * *Security Fix*: Using an XPath expression employing a scalar expression as a FilterExpr (http://www.w3.org/TR/xpath#NT-FilterExpr) with `ExtractValue()' or `UpdateXML()' caused the server to crash. Such expressions now cause an error instead. (Bug #42495) * *Incompatible Change*: The fix for Bug#33699 introduced a change to the *Note `UPDATE': update. statement such that assigning `NULL' to a `NOT NULL' column caused an error even when strict SQL mode was not enabled. The original behavior before was that such assignments caused an error only in strict SQL mode, and otherwise set the column to the implicit default value for the column data type and generated a warning. (For information about implicit default values, see *Note data-type-defaults::.) The change caused compatibility problems for applications that relied on the original behavior. It also caused replication problems between servers that had the original behavior and those that did not, for applications that assigned `NULL' to `NOT NULL' columns in *Note `UPDATE': update. statements without strict SQL mode enabled. This change has been reverted so that *Note `UPDATE': update. again had the original behavior. Problems can still occur if you replicate between servers that have the modified *Note `UPDATE': update. behavior and those that do not. (Bug #39265) * *Important Change*: When using the MySQL Instance Configuration Wizard with a configuration where you already have an existing installation with a custom `datadir', the wizard could reset the data to the default data directory. When performing an upgrade installation in this situation, you must re-specify your custom settings, including the `datadir', to ensure that your configuration file is not reset to the default values. (Bug #37534) * *Important Change*: Uninstalling MySQL using the MySQL installer on Windows would delete the `my.ini' file. The file is no longer deleted. In addition, when a new installation is conducted, any existing cofiguration file will be renamed to `myDATETIME.ini.bak' during configuration. (Bug #36493) * *Important Change*: When installing MySQL on Windows, it was possible to install multiple editions (Complete, and Essential, for example) of the same version of MySQL, leading to two separate entries in the installed packages which were impossible to isolate. This could lead to problems with installation and uninstallation. The MySQL installer on Windows no longers permits multiple installations of the same version of MySQL on a single machine. (Bug #4217) * *Replication*: *Note `START SLAVE UNTIL': start-slave. did not work correctly with `--replicate-same-server-id' enabled; when started with this option, the slave did not perform events recorded in the relay log and that originated from a different master. Log rotation events are automatically generated and written when rotating the binary log or relay log. Such events for relay logs are usually ignored by the slave SQL thread because they have the same server ID as that of the slave. However, when `--replicate-same-server-id' was enabled, the rotation event for the relay log was treated as if it originated on the master, because the log's name and position were incorrectly updated. This caused the `MASTER_POS_WAIT()' function always to return `NULL' and thus to fail. (Bug #38734, Bug #38934) * *Replication*: *Note `TRUNCATE TABLE': truncate-table. statements failed to replicate when statement-based binary logging mode was not available. The issue was observed when using *Note `InnoDB': innodb-storage-engine. with the transaction isolation level set to `READ UNCOMMITTED' (thus forcing *Note `InnoDB': innodb-storage-engine. not to permit statement-based logging). However, the same behavior could be reproduced using any transactional storage engine supporting only row-based logging, regardless of the isolation level. This was due to two separate problems: 1. An error was printed by *Note `InnoDB': innodb-storage-engine. for *Note `TRUNCATE TABLE': truncate-table. when using statement-based logging mode where the transaction isolation level was set to `READ COMMITTED' or `READ UNCOMMITTED', because *Note `InnoDB': innodb-storage-engine. permits statement-based replication for DML statements. However, *Note `TRUNCATE TABLE': truncate-table. is not transactional; since it is the equivalent of *Note `DROP TABLE': drop-table. followed by *Note `CREATE TABLE': create-table, it is actually DDL, and should therefore be permitted to be replicated as a statement. 2. *Note `TRUNCATE TABLE': truncate-table. was not logged in mixed mode because of the error just described; however, this error was not reported to the client. As a result of this fix, *Note `TRUNCATE TABLE': truncate-table. is now treated as DDL for purposes of binary logging and replication; that is, it is always logged as a statement and so no longer causes an error when replicated using a transactional storage engine such as *Note `InnoDB': innodb-storage-engine. (Bug #36763) See also Bug #42643. * *Replication*: *Note `mysqlbinlog': mysqlbinlog. replay of *Note `CREATE TEMPORARY TABLE ... LIKE': create-table. statements and of *Note `TRUNCATE TABLE': truncate-table. statements used on temporary tables failed with Error 1146 (`Table ... doesn't exist'). (Bug #35583) * *Replication*: In statement mode, *Note `mysqlbinlog': mysqlbinlog. failed to issue a `SET @@autommit' statement when the autocommit mode was changed. (Bug #34541) * *Replication*: *Note `LOAD DATA INFILE': load-data. statements did not replicate correctly from a master running MySQL 4.1 to a slave running MySQL 5.1 or later. (Bug #31240) * The use by `libedit' of the `__weak_reference()' macro caused compilation failure on FreeBSD. (Bug #42817) * A `'%'' character in SQL statements could cause the server to crash. (Bug #42634) * An optimization introduced for Bug#37553 required an explicit cast to be added for some uses of `TIMEDIFF()' because automatic casting could produce incorrect results. (It was necessary to use `TIME(TIMEDIFF(...))'.) (Bug #42525) * On the IBM i5 platform, the MySQL configuration process caused the system version of `pthread_setschedprio()' to be used. This function returns `SIGILL' on i5 because it is not supported, causing the server to crash. Now the `my_pthread_setprio()' function in the `mysys' library is used instead. (Bug #42524) * The SSL certficates included with MySQL distributions were regenerated because the previous ones had expired. (Bug #42366) * User variables within triggers could cause a crash if the *Note `mysql_change_user()': mysql-change-user. C API function was invoked. (Bug #42188) * Dependent subqueries such as the following caused a memory leak proportional to the number of outer rows: SELECT COUNT(*) FROM t1, t2 WHERE t2.b IN (SELECT DISTINCT t2.b FROM t2 WHERE t2.b = t1.a); (Bug #42037) * Some queries using `NAME_CONST(.. COLLATE ...)' led to a server crash due to a failed type cast. (Bug #42014) * On Mac OS X, some of the universal client libraries were not actually universal and were missing code for one or more architectures. (Bug #41940) * String reallocation could cause memory overruns. (Bug #41868) * *Note `mysql_install_db': mysql-install-db. did not pass some relevant options to *Note `mysqld': mysqld. (Bug #41828) * Setting `innodb_locks_unsafe_for_binlog' should be equivalent to setting the transaction isolation level to `READ COMMITTED'. However, if both of those things were done, nonmatching semi-consistently read rows were not unlocked when they should have been. (Bug #41671) * *Note `REPAIR TABLE': repair-table. crashed for compressed *Note `MyISAM': myisam-storage-engine. tables. (Bug #41574) * For a *Note `TIMESTAMP NOT NULL DEFAULT ...': datetime. column, storing `NULL' as the return value from some functions caused a `cannot be NULL' error. `NULL' returns now correctly cause the column default value to be stored. (Bug #41370) * The server cannot execute *Note `INSERT DELAYED': insert. statements when statement-based binary logging is enabled, but the error message displayed only the table name, not the entire statement. (Bug #41121) * `FULLTEXT' indexes did not work for Unicode columns that used a custom UCA collation. (Bug #41084) * The Windows installer displayed incorrect product names in some images. (Bug #40845) * Changing `innodb_thread_concurrency' at runtime could cause errors. (Bug #40760) * `SELECT' statements could be blocked by *Note `INSERT DELAYED': insert. statements that were waiting for a lock, even with `low_priority_updates' enabled. (Bug #40536) * For `InnoDB' tables that used `ROW_FORMAT=REDUNDANT', storage size of `NULL' columns could be determined incorrectly. (Bug #40369) * The query cache stored only partial query results if a statement failed while the results were being sent to the client. This could cause other clients to hang when trying to read the cached result. Now if a statement fails, the result is not cached. (Bug #40264) * When a *Note `MEMORY': memory-storage-engine. table became full, the error generated was returned to the client but was not written to the error log. (Bug #39886) * With row-based binary logging, replication of `InnoDB' tables containing `NULL'-valued *Note `BIT': numeric-types. columns could fail. (Bug #39648) * The expression `ROW(...) IN (SELECT ... FROM DUAL)' always returned `TRUE'. (Bug #39069) * The greedy optimizer could cause a server crash due to improper handling of nested outer joins. (Bug #38795) * Use of `COUNT(DISTINCT)' prevented `NULL' testing in the `HAVING' clause. (Bug #38637) * The `innodb_stats_on_metadata' system variable was not displayed by *Note `SHOW VARIABLES': show-variables. and was not settable at runtime. (Bug #38189) * Enabling the `sync_frm' system variable had no effect on the handling of `.frm' files for views. (Bug #38145) * The embedded server truncated some error messages. (Bug #37995) * For comparison of `NULL' to a subquery result inside `IS NULL', the comparison could evaluate to `NULL' rather than to `TRUE' or `FALSE'. This occurred for expressions such as: SELECT ... WHERE NULL IN (SELECT ...) IS NULL (Bug #37822) * Setting `myisam_repair_threads' greater than 1 caused a server crash for table repair or alteration operations for *Note `MyISAM': myisam-storage-engine. tables with multiple `FULLTEXT' indexes. (Bug #37756) * When using the MySQL MSI Installer on Windows and selecting `Back' after a choosing Repair, you would be returned to the Fresh Install section of the installer. You are now correctly returned to the Install, Repair, Modify screen. (Bug #37294) * The *Note `mysql': mysql. client sometimes improperly interpreted string escape sequences in nonstring contexts. (Bug #36391) * The query cache stored packets containing the server status of the time when the cached statement was run. This might lead to an incorrect transaction status on the client side if a statement was cached during a transaction and later served outside a transaction context (or vice versa). (Bug #36326) * If the system time was adjusted backward during query execution, the apparent execution time could be negative. But in some cases these queries would be written to the slow query log, with the negative execution time written as a large unsigned number. Now statements with apparent negative execution time are not written to the slow query log. (Bug #35396) * `libmysqld' was not built with all character sets. (Bug #32831) * For *Note `mysqld_multi': mysqld-multi, using the `--mysqld=mysqld_safe' option caused the `--defaults-file' and `--defaults-extra-file' options to behave the same way. (Bug #32136) * Attempts to open a valid *Note `MERGE': merge-storage-engine. table sometimes resulted in a `ER_WRONG_MRG_TABLE' error. This happened after failure to open an invalid *Note `MERGE': merge-storage-engine. table had also generated an `ER_WRONG_MRG_TABLE' error. (Bug #32047) * For Solaris package installation using `pkgadd', the postinstall script failed, causing the system tables in the `mysql' database not to be created. (Bug #31164) * If the default database was dropped, the value of `character_set_database' was not reset to `character_set_server' as it should have been. (Bug #27208)  File: manual.info, Node: news-5-1-31sp1, Next: news-5-1-31, Prev: news-5-1-32, Up: news-5-1-x D.1.36 Release Notes for MySQL Enterprise 5.1.31sp1 [QSP] (19 March 2009) ------------------------------------------------------------------------- This is a _Service Pack_ release of the MySQL Enterprise Server 5.1. This section documents all changes and bugfixes that have been applied since the last MySQL Enterprise Server release (5.1.31). If you would like to receive more fine-grained and personalized _update alerts_ about fixes that are relevant to the version and features you use, please consider subscribing to _MySQL Enterprise_ (a commercial MySQL offering). For more details please see http://www.mysql.com/products/enterprise/advisors.html. *Functionality added or changed:* * The `libedit' library was upgraded to version 2.11. (Bug #42433) *Bugs fixed:* * *Security Fix*: Using an XPath expression employing a scalar expression as a FilterExpr (http://www.w3.org/TR/xpath#NT-FilterExpr) with `ExtractValue()' or `UpdateXML()' caused the server to crash. Such expressions now cause an error instead. (Bug #42495) * On the IBM i5 platform, the MySQL configuration process caused the system version of `pthread_setschedprio()' to be used. This function returns `SIGILL' on i5 because it is not supported, causing the server to crash. Now the `my_pthread_setprio()' function in the `mysys' library is used instead. (Bug #42524) * The SSL certficates included with MySQL distributions were regenerated because the previous ones had expired. (Bug #42366) * User variables within triggers could cause a crash if the *Note `mysql_change_user()': mysql-change-user. C API function was invoked. (Bug #42188) * Some queries using `NAME_CONST(.. COLLATE ...)' led to a server crash due to a failed type cast. (Bug #42014)  File: manual.info, Node: news-5-1-31, Next: news-5-1-30, Prev: news-5-1-31sp1, Up: news-5-1-x D.1.37 Changes in MySQL 5.1.31 (19 January 2009) ------------------------------------------------ *Functionality added or changed:* * `MySQL-shared-compat-advanced-gpl-5.1.31-0.*.rpm' and `MySQL-shared-compat-advanced-5.1.31-0.*.rpm' packages are now available. These client library compatibility packages are like the `MySQL-shared-compat' package, but are for the `MySQL Enterprise Server --- Advanced Edition' products. Install these packages rather than the normal `MySQL-shared-compat' package if you want to included shared client libraries for older MySQL versions. (Bug #41838) * A new status variable, `Queries', indicates the number of statements executed by the server. This includes statements executed within stored programs, unlike the `Questions' variable which includes only statements sent to the server by clients. (Bug #41131) * Performance of `SELECT *' retrievals from *Note `INFORMATION_SCHEMA.COLUMNS': columns-table. was improved slightly. (Bug #38918) * Previously, index hints did not work for `FULLTEXT' searches. Now they work as follows: For natural language mode searches, index hints are silently ignored. For example, `IGNORE INDEX(i)' is ignored with no warning and the index is still used. For boolean mode searches, index hints with `FOR ORDER BY' or `FOR GROUP BY' are silently ignored. Index hints with `FOR JOIN' or no `FOR' modifier are honored. In contrast to how hints apply for non-`FULLTEXT' searches, the hint is used for all phases of query execution (finding rows and retrieval, grouping, and ordering). This is true even if the hint is given for a non-`FULLTEXT' index. (Bug #38842) *Bugs fixed:* * *Performance*: For an `InnoDB' table, *Note `DROP TABLE': drop-table. or *Note `ALTER TABLE ... DISCARD TABLESPACE': alter-table. could take a long time or cause a server crash. (Bug #39939) * *Important Change*: *Replication*: If a trigger was defined on an *Note `InnoDB': innodb-storage-engine. table and this trigger updated a nontransactional table, changes performed on the *Note `InnoDB': innodb-storage-engine. table were replicated and were visible on the slave before they were committed on the master, and were not rolled back on the slave after a successful rollback of those changes on the master. As a result of the fix for this issue, the semantics of mixing nontransactional and transactional tables in a transaction have changed. Previously, if the initial statements in a transaction contained nontransactional changes, those statements were written directly to the binary log. Now, any statement appearing after a *Note `BEGIN': commit. (or immediately following a *Note `COMMIT': commit. if `autocommit' = 0) is always considered part of the transaction and cached. This means that nontransactional changes do not propagate to the slave until the transaction is committed and thus written to the binary log. See *Note replication-features-transactions::, for more information about this change in behavior. (Bug #40116) * *Important Change*: The MSI installer packages for Windows are now digitally signed with a certificate, enabling installation on Windows where only certified packages are permitted by group policy or configuration. As part of this change, and to comply with the certified installer requirements, the `Setup.exe' versions of the MySQL installer have been discontinued. You must have Windows Installer support in your Windows installation to use the MSI install package. This is a standard component on Windows XP SP2 and higher. For earlier versions, you can download the Microsoft Installer support from Microsoft.com. (Bug #36409) * *Partitioning*: *Replication*: Changing the transaction isolation level while replicating partitioned `InnoDB' tables could cause statement-based logging to fail. (Bug #39084) * *Partitioning*: A comparison with an invalid `DATE' value in a query against a partitioned table could lead to a crash of the MySQL server. *Note*: Invalid `DATE' and `DATETIME' values referenced in the `WHERE' clause of a query on a partitioned table are treated as `NULL'. See *Note partitioning-pruning::, for more information. (Bug #40972) * *Partitioning*: A query on a user-partitioned table caused MySQL to crash, where the query had the following characteristics: * The query's `WHERE' clause referenced an indexed column that was also in the partitioning key. * The query's `WHERE' clause included a value found in the partition. * The query's `WHERE' clause used the `<' or `<>' operators to compare with the indexed column's value with a constant. * The query used an `ORDER BY' clause, and the same indexed column was used in the `ORDER BY' clause. * The `ORDER BY' clause used an explcit or implicit `ASC' sort priority. Two examples of such a query are given here, where `a' represents an indexed column used in the table's partitioning key: 1. SELECT * FROM TABLE WHERE a < CONSTANT ORDER BY a; 2. SELECT * FROM TABLE WHERE a <> CONSTANT ORDER BY a; This bug was introduced in MySQL 5.1.29. (Bug #40954) This regression was introduced by Bug #30573, Bug #33257, Bug #33555. * *Partitioning*: With `READ COMMITTED' transaction isolation level, *Note `InnoDB': innodb-storage-engine. uses a semi-consistent read that releases nonmatching rows after MySQL has evaluated the `WHERE' clause. However, this was not happening if the table used partitions. (Bug #40595) * *Partitioning*: A query that timed out when run against a partitioned table failed silently, without providing any warnings or errors, rather than returning `Lock wait timeout exceeded'. (Bug #40515) * *Partitioning*: `ALTER TABLE ... REORGANIZE PARTITION' could crash the server when the number of partitions was not changed. (Bug #40389) See also Bug #41945. * *Partitioning*: For a partitioned table having an `AUTO_INCREMENT' column: If the first statement following a start of the server or a `FLUSH TABLES' statement was an `UPDATE' statement, the `AUTO_INCREMENT' column was not incremented correctly. (Bug #40176) * *Partitioning*: The server attempted to execute the statements `ALTER TABLE ... ANALYZE PARTITION', `ALTER TABLE ... CHECK PARTITION', `ALTER TABLE ... OPTIMIZE PARTITION', and `ALTER TABLE ... REORGANIZE PARTITION' on tables that were not partitioned. (Bug #39434) See also Bug #20129. * *Partitioning*: The value of the `CREATE_COLUMNS' column in *Note `INFORMATION_SCHEMA.TABLES': tables-table. was not `partitioned' for partitioned tables. (Bug #38909) * *Partitioning*: When executing an `ORDER BY' query on a partitioned `InnoDB' table using an index that was not in the partition expression, the results were sorted on a per-partition basis rather than for the table as a whole. (Bug #37721) * *Partitioning*: Dropping or creating an index on a partitioned table managed by the `InnoDB' Plugin locked the table. (Bug #37453) * *Partitioning*: Partitioned table checking sometimes returned a warning with an error code of 0, making proper response to errors impossible. The fix also renders the error message subject to translation in non-English deployments. (Bug #36768) * *Partitioning*: `SHOW TABLE STATUS' could show a nonzero value for the `Mean record length' of a partitioned *Note `InnoDB': innodb-storage-engine. table, even if the table contained no rows. (Bug #36312) * *Partitioning*: When `SHOW CREATE TABLE' was used on a partitioned table, all of the table's `PARTITION' and `SUBPARTITION' clauses were output on a single line, making it difficult to read or parse. (Bug #14326) * *Replication*: Per-table `AUTO_INCREMENT' option values were not replicated correctly for *Note `InnoDB': innodb-storage-engine. tables. (Bug #41986) * *Replication*: Some `log_event' types did not skip the post-header when reading. (Bug #41961) * *Replication*: Attempting to read a binary log containing an `Incident_log_event' having an invalid incident number could cause the debug server to crash. (Bug #40482) * *Replication*: When using row-based replication, an update of a primary key that was rolled back on the master due to a duplicate key error was not rolled back on the slave. (Bug #40221) * *Replication*: When rotating relay log files, the slave deletes relay log files and then edits the relay log index file. Formerly, if the slave shut down unexpectedly between these two events, the relay log index file could then reference relay logs that no longer existed. Depending on the circumstances, this could when restarting the slave cause either a race condition or the failure of replication. (Bug #38826, Bug #39325) * *Replication*: With row-based replication, `UPDATE' and `DELETE' statements using `LIMIT' and a table's primary key could produce different results on the master and slave. (Bug #38230) * *Note `resolve_stack_dump': resolve-stack-dump. was unable to resolve the stack trace format produced by *Note `mysqld': mysqld. in MySQL 5.1 and up (see *Note using-stack-trace::). (Bug #41612) * In example option files provided in MySQL distributions, the `thread_stack' value was increased from 64K to 128K. (Bug #41577) * The optimizer could ignore an error and rollback request during a filesort, causing an assertion failure. (Bug #41543) * `DATE_FORMAT()' could cause a server crash for year-zero dates. (Bug #41470) * *Note `SET PASSWORD': set-password. caused a server crash if the account name was given as `CURRENT_USER()'. (Bug #41456) * When a repair operation was carried out on a *Note `CSV': csv-storage-engine. table, the debug server crashed. (Bug #41441) * When substituting system constant functions with a constant result, the server was not expecting `NULL' function return values and could crash. (Bug #41437) * Queries such as `SELECT ... CASE AVG(...) WHEN ...' that used aggregate functions in a `CASE' expression crashed the server. (Bug #41363) * *Note `INSERT INTO .. SELECT ... FROM': insert. and *Note `CREATE TABLE ... SELECT ... FROM': create-table. a TEMPORARY table could inadvertently change the locking type of the temporary table from a write lock to a read lock, causing statement failure. (Bug #41348) * The *Note `INFORMATION_SCHEMA.SCHEMA_PRIVILEGES': schema-privileges-table. table was limited to 7680 rows. (Bug #41079) * In debug builds, obsolete debug code could be used to crash the server. (Bug #41041) * Some queries that used a `range checked for each record' scan could return incorrect results. (Bug #40974) See also Bug #44810. * Certain *Note `SELECT': select. queries could fail with a `Duplicate entry' error. (Bug #40953) * For debug servers, *Note `OPTIMIZE TABLE': optimize-table. on a compressed table caused a server crash. (Bug #40949) * Accessing user variables within triggers could cause a server crash. (Bug #40770) * `IF(..., CAST(LONGTEXT_VAL AS UNSIGNED), SIGNED_VAL)' as an argument to an aggregate function could cause an assertion failure. (Bug #40761) * For single-table *Note `UPDATE': update. statements, an assertion failure resulted from a runtime error in a stored function (such as a recursive function call or an attempt to update the same table as in the *Note `UPDATE': update. statement). (Bug #40745) * *Note `TRUNCATE TABLE': truncate-table. for an `InnoDB' table did not flush cached queries for the table. (Bug #40386) * Prepared statements permitted invalid dates to be inserted when the `ALLOW_INVALID_DATES' SQL mode was not enabled. (Bug #40365) * `mc.exe' is no longer needed to compile MySQL on Windows. This makes it possible to build MySQL from source using Visual Studio Express 2008. (Bug #40280) * The `':'' character was incorrectly not permitted in table names. (Bug #40104) * Support for the `revision' field in `.frm' files has been removed. This addresses the downgrading problem introduced by the fix for Bug#17823. (Bug #40021) * Retrieval speed from the following `INFORMATION_SCHEMA' tables was improved by shortening the `VARIABLE_VALUE' column to 1024 characters: *Note `GLOBAL_VARIABLES': variables-table, *Note `SESSION_VARIABLES': variables-table, *Note `GLOBAL_STATUS': status-table, and *Note `SESSION_STATUS': status-table. As a result of this change, any variable value longer than 1024 characters will be truncated with a warning. This affects only the `init_connect' system variable. (Bug #39955) * If the operating system is configured to return leap seconds from OS time calls or if the MySQL server uses a time zone definition that has leap seconds, functions such as `NOW()' could return a value having a time part that ends with `:59:60' or `:59:61'. If such values are inserted into a table, they would be dumped as is by *Note `mysqldump': mysqldump. but considered invalid when reloaded, leading to backup/restore problems. Now leap second values are returned with a time part that ends with `:59:59'. This means that a function such as `NOW()' can return the same value for two or three consecutive seconds during the leap second. It remains true that literal temporal values having a time part that ends with `:59:60' or `:59:61' are considered invalid. For additional details about leap-second handling, see *Note time-zone-leap-seconds::. (Bug #39920) * The server could crash during a sort-order optimization of a dependent subquery. (Bug #39844) * For a server started with the `--temp-pool' option on Windows, temporary file creation could fail. This option now is ignored except on Linux systems, which was its original intended scope. (Bug #39750) * *Note `ALTER TABLE': alter-table. on a table with `FULLTEXT' index that used a pluggable `FULLTEXT' parser could cause debug servers to crash. (Bug #39746) * With the `ONLY_FULL_GROUP_BY' SQL mode enabled, the check for nonaggregated columns in queries with aggregate functions, but without a `GROUP BY' clause was treating all the parts of the query as if they were in the select list. This is fixed by ignoring the nonaggregated columns in the `WHERE' clause. (Bug #39656) * The server crashed if an integer field in a CSV file did not have delimiting quotation marks. (Bug #39616) * Creating a table with a comment of 62 characters or longer caused a server crash. (Bug #39591) * The `do_abi_check' program run during the build process depends on `mysql_version.h' but that file was not created first, resulting in build failure. (Bug #39571) * *Note `CHECK TABLE': check-table. failed for *Note `MyISAM': myisam-storage-engine. `INFORMATION_SCHEMA' tables. (Bug #39541) * On 64-bit Windows systems, the server accepted `key_buffer_size' values larger than 4GB, but allocated less. (For example, specifying a value of 5GB resulted in 1GB being allocated.) (Bug #39494) * `InnoDB' could hang trying to open an adaptive hash index. (Bug #39483) * Following *Note `ALTER TABLE ... DISCARD TABLESPACE': alter-table. for an `InnoDB' table, an attempt to determine the free space for the table before the *Note `ALTER TABLE': alter-table. operation had completely finished could cause a server crash. (Bug #39438) * Use of the `PACK_KEYS' or `MAX_ROWS' table option in *Note `ALTER TABLE': alter-table. should have triggered table reconstruction but did not. (Bug #39372) * The server returned a column type of *Note `VARBINARY': binary-varbinary. rather than *Note `DATE': datetime. as the result from the `COALESCE()', `IFNULL()', `IF()', `GREATEST()', or `LEAST()' functions or `CASE' expression if the result was obtained using `filesort' in an anonymous temporary table during the query execution. (Bug #39283) * A server built using yaSSL for SSL support would crash if configured to use an RSA key and a client sent a cipher list containing a non-RSA key as acceptable. (Bug #39178) * When built with Valgrind, the server failed to access tables created with the `DATA DIRECTORY' or `INDEX DIRECTORY' table option. (Bug #39102) * With binary logging enabled *Note `CREATE VIEW': create-view. was subject to possible buffer overwrite and a server crash. (Bug #39040) * The fast mutex implementation was subject to excessive lock contention. (Bug #38941) * Use of *Note `InnoDB': innodb-storage-engine. monitoring (*Note `SHOW ENGINE INNODB STATUS': show-engine. or one of the *Note `InnoDB': innodb-storage-engine. Monitor tables) could cause a server crash due to invalid access to a shared variable in a concurrent environment. (Bug #38883) * `InnoDB' could fail to generate `AUTO_INCREMENT' values after an *Note `UPDATE': update. statement for the table. (Bug #38839) * If delayed insert failed to upgrade the lock, it did not free the temporary memory storage used to keep newly constructed *Note `BLOB': blob. values in memory, resulting in a memory leak. (Bug #38693) * On Windows, a five-second delay occurred at shutdown of applications that used the embedded server. (Bug #38522) * On Solaris, a scheduling policy applied to the main server process could be unintentionally overwritten in client-servicing threads. (Bug #38477) * Building MySQL on FreeBSD would result in a failure during the `gen_lex_hash' phase of the build. (Bug #38364) * On Windows, the embedded server would crash in *Note `mysql_library_init()': mysql-library-init. if the language file was missing. (Bug #38293) * A mix of *Note `TRUNCATE TABLE': truncate-table. with *Note `LOCK TABLES': lock-tables. and *Note `UNLOCK TABLES': lock-tables. for an `InnoDB' could cause a server crash. (Bug #38231) * The `ExtractValue()' function did not work correctly with XML documents containing a `DOCTYPE' declaration. (Bug #38227) * Queries with a `HAVING' clause could return a spurious row. (Bug #38072) * The Event Scheduler no longer logs `started in thread' or `executed' successfully messages to the error log. (Bug #38066) * Use of spatial data types in prepared statements could cause memory leaks or server crashes. (Bug #37956, Bug #37671) * An error in a debugging check caused crashes in debug servers. (Bug #37936) * A *Note `SELECT': select. with a `NULL NOT IN' condition containing a complex subquery from the same table as in the outer select caused an assertion failure. (Bug #37894) * The presence of a `/* ... */' comment preceding a query could cause `InnoDB' to use unnecessary gap locks. (Bug #37885) * Use of an uninitialized constant in *Note `EXPLAIN': explain. evaluation caused an assertion failure. (Bug #37870) * When using *Note `ALTER TABLE': alter-table. on an *Note `InnoDB': innodb-storage-engine. table, the `AUTO_INCREMENT' value could be changed to an incorrect value. (Bug #37788) * Primary keys were treated as part of a covering index even if only a prefix of a key column was used. (Bug #37742) * Renaming an *Note `ARCHIVE': archive-storage-engine. table to the same name with different lettercase and then selecting from it could cause a server crash. (Bug #37719) * The `MONTHNAME()' and `DAYNAME()' functions returned a binary string, so that using `LOWER()' or `UPPER()' had no effect. Now `MONTHNAME()' and `DAYNAME()' return a value in `character_set_connection' character set. (Bug #37575) * `TIMEDIFF()' was erroneously treated as always returning a positive result. Also, `CAST()' of *Note `TIME': time. values to *Note `DECIMAL': numeric-types. dropped the sign of negative values. (Bug #37553) See also Bug #42525. * *Note `SHOW PROCESSLIST': show-processlist. displayed `copy to tmp table' when no such copy was occurring. (Bug #37550) * *Note `mysqlcheck': mysqlcheck. used *Note `SHOW FULL TABLES': show-tables. to get the list of tables in a database. For some problems, such as an empty `.frm' file for a table, this would fail and *Note `mysqlcheck': mysqlcheck. then would neglect to check other tables in the database. (Bug #37527) * Updating a view with a subquery in the `CHECK' option could cause an assertion failure. (Bug #37460) * Statements that displayed the value of system variables (for example, *Note `SHOW VARIABLES': show-variables.) expect variable values to be encoded in `character_set_system'. However, variables set from the command line such as `basedir' or `datadir' were encoded using `character_set_filesystem' and not converted correctly. (Bug #37339) * *Note `CREATE INDEX': create-index. could crash with `InnoDB' plugin 1.0.1. (Bug #37284) * Certain boolean-mode `FULLTEXT' searches that used the truncation operator did not return matching records and calculated relevance incorrectly. (Bug #37245) * On a 32-bit server built without big tables support, the offset argument in a `LIMIT' clause might be truncated due to a 64-bit to 32-bit cast. (Bug #37075) * For an `InnoDB' table with a `FOREIGN KEY' constraint, *Note `TRUNCATE TABLE': truncate-table. may be performed using row by row deletion. If an error occurred during this deletion, the table would be only partially emptied. Now if an error occurs, the truncation operation is rolled back and the table is left unchanged. (Bug #37016) * The code for the `ut_usectime()' function in `InnoDB' did not handle errors from the `gettimeofday()' system call. Now it retries `gettimeofday()' several times and updates the value of the `Innodb_row_lock_time_max' status variable only if `ut_usectime()' was successful. (Bug #36819) * Use of `CONVERT()' with `GROUP BY' to convert numeric values to *Note `CHAR': char. could return truncated results. (Bug #36772) * The *Note `mysql': mysql. client, when built with Visual Studio 2005, did not display Japanese characters. (Bug #36279) * *Note `CREATE INDEX': create-index. for `InnoDB' tables could under very rare circumstances cause the server to crash.. (Bug #36169) * A read past the end of the string could occur while parsing the value of the `--innodb-data-file-path' option. (Bug #36149) * Setting the `slave_compressed_protocol' system variable to `DEFAULT' failed in the embedded server. (Bug #35999) * For upgrades to MySQL 5.1 or higher, *Note `mysql_upgrade': mysql-upgrade. did not re-encode database or table names that contained nonalphanumeric characters. (They would still appear after the upgrade with the `#mysql50#' prefix described in *Note identifier-mapping::.) To correct this problem, it was necessary to run *Note `mysqlcheck --all-databases --check-upgrade --fix-db-names --fix-table-names': mysqlcheck. manually. *Note `mysql_upgrade': mysql-upgrade. now runs that command automatically after performing the initial upgrade. (Bug #35934) * *Note `SHOW CREATE TABLE': show-create-table. did not display a printable value for the default value of *Note `BIT': numeric-types. columns. (Bug #35796) * The columns that store character set and collation names in several `INFORMATION_SCHEMA' tables were lengthened because they were not long enough to store some possible values: *Note `SCHEMATA': schemata-table, *Note `TABLES': tables-table, *Note `COLUMNS': columns-table, *Note `CHARACTER_SETS': character-sets-table, *Note `COLLATIONS': collations-table, and *Note `COLLATION_CHARACTER_SET_APPLICABILITY': collation-character-set-applicability-table. (Bug #35789) * The `max_length' metadata value was calculated incorrectly for the `FORMAT()' function, which could cause incorrect result set metadata to be sent to clients. (Bug #35558) * `InnoDB' was not updating the `Handler_delete' or `Handler_update' status variables. (Bug #35537) * `InnoDB' could fail to generate `AUTO_INCREMENT' values if rows previously had been inserted containing literal values for the `AUTO_INCREMENT' column. (Bug #35498, Bug #36411, Bug #39830) * The `CREATE_OPTIONS' column for *Note `INFORMATION_SCHEMA.TABLES': tables-table. did not display the `KEY_BLOCK_SIZE' option. (Bug #35275) * Selecting from an `INFORMATION_SCHEMA' table into an incorrectly defined *Note `MERGE': merge-storage-engine. table caused an assertion failure. (Bug #35068) * *Note `perror': perror. on Windows did not know about Win32 system error codes. (Bug #34825) * *Note `EXPLAIN EXTENDED': explain. evaluation of aggregate functions that required a temporary table caused a server crash. (Bug #34773) * *Note `SHOW GLOBAL STATUS': show-status. shows values that aggregate the session status values for all threads. This did not work correctly for the embedded server. (Bug #34517) * *Note `mysqldumpslow': mysqldumpslow. did not aggregate times. (Bug #34129) * *Note `mysql_config': mysql-config. did not output `-ldl' (or equivalent) when needed for `--libmysqld-libs', so its output could be insufficient to build applications that use the embedded server. (Bug #34025) * The *Note `mysql': mysql. client incorrectly parsed statements containing the word `delimiter' in mid-statement. This fix is different from the one applied for this bug in MySQL 5.1.26. (Bug #33812) See also Bug #38158. * For a stored procedure containing a `SELECT * ... RIGHT JOIN' query, execution failed for the second call. (Bug #33811) * Previously, use of index hints with views (which do not have indexes) produced the error `ERROR 1221 (HY000): Incorrect usage of USE/IGNORE INDEX and VIEW'. Now this produces `ERROR 1176 (HY000): Key '...' doesn't exist in table '...'', the same error as for base tables without an appropriate index. (Bug #33461) * Three conditions were discovered that could cause an upgrade from MySQL 5.0 to 5.1 to fail: 1) Triggers associated with a table that had a `#mysql50#' prefix in the name could cause assertion failure. 2) *Note `ALTER DATABASE ... UPGRADE DATA DIRECTORY NAME': alter-database. failed for databases that had a `#mysql50#' prefix if there were triggers in the database. 3) *Note `mysqlcheck --fix-table-name': mysqlcheck. didn't use UTF8 as the default character set, resulting in parsing errors for tables with nonlatin symbols in their names and trigger definitions. (Bug #33094, Bug #41385) * Execution of a prepared statement that referred to a system variable caused a server crash. (Bug #32124) * Some division operations produced a result with incorrect precision. (Bug #31616) * Queries executed using join buffering of *Note `BIT': numeric-types. columns could produce incorrect results. (Bug #31399) * `ALTER TABLE CONVERT TO CHARACTER SET' did not convert *Note `TINYTEXT': blob. or *Note `MEDIUMTEXT': blob. columns to a longer text type if necessary when converting the column to a different character set. (Bug #31291) * Server variables could not be set to their current values on Linux platforms. (Bug #31177) See also Bug #6958. * For installation on Solaris using `pkgadd' packages, the *Note `mysql_install_db': mysql-install-db. script was generated in the `scripts' directory, but the temporary files used during the process were left there and not deleted. (Bug #31052) * Static storage engines and plugins that were disabled and dynamic plugins that were installed but disabled were not listed in the `INFORMATION_SCHEMA' appropriate *Note `PLUGINS': plugins-table. or *Note `ENGINES': engines-table. table. (Bug #29263) * Some *Note `SHOW': show. statements and retrievals from the `INFORMATION_SCHEMA' *Note `TRIGGERS': triggers-table. and *Note `EVENTS': events-table. tables used a temporary table and incremented the `Created_tmp_disk_tables' status variable, due to the way that `TEXT' columns are handled. The `TRIGGERS.SQL_MODE', `TRIGGERS.DEFINER', and `EVENTS.SQL_MODE' columns now are *Note `VARCHAR': char. to avoid this problem. (Bug #29153) * For several read only system variables that were viewable with *Note `SHOW VARIABLES': show-variables, attempting to view them with `SELECT @@VAR_NAME' or set their values with `SET' resulted in an `unknown system variable' error. Now they can be viewed with `SELECT @@VAR_NAME' and attempting to set their values results in a message indicating that they are read only. (Bug #28234) * On Windows, Visual Studio does not take into account some x86 hardware limitations, which led to incorrect results converting large *Note `DOUBLE': numeric-types. values to unsigned *Note `BIGINT': numeric-types. values. (Bug #27483) * SSL support was not included in some `generic' RPM packages. (Bug #26760) * The `Questions' status variable is intended as a count of statements sent by clients to the server, but was also counting statements executed within stored routines. (Bug #24289) * Setting the session value of the `max_allowed_packet' or `net_buffer_length' system variable was permitted but had no effect. The session value of these variables is now read only. (Bug #22891) See also Bug #32223. * A race condition between the *Note `mysqld.exe': mysqld. server and the Windows service manager could lead to inability to stop the server from the service manager. (Bug #20430) * On Windows, moving an `InnoDB' `.ibd' file and then symlinking to it in the database directory using a `.sym' file caused a server crash. (Bug #11894)  File: manual.info, Node: news-5-1-30, Next: news-5-1-29, Prev: news-5-1-31, Up: news-5-1-x D.1.38 Changes in MySQL 5.1.30 (14 November 2008 General Availability) ---------------------------------------------------------------------- *Bugs fixed:* * *Partitioning*: A `SELECT' using a range `WHERE' condition with an `ORDER BY' on a partitioned table caused a server crash. (Bug #40494) * *Replication*: Executing *Note `SHOW BINLOG EVENTS': show-binlog-events. increased the value of `max_allowed_packet' applying to the session that executed the statement. (Bug #55322) * *Replication*: Row-based replication failed with nonpartitioned `MyISAM' tables having no indexes. (Bug #40004) * With statement-based binary logging format and a transaction isolation level of `READ COMMITTED' or stricter, `InnoDB' printed an error because statement-based logging might lead to inconsistency between master and slave databases. However, this error was printed even when binary logging was not enabled (in which case, no such inconsistency can occur). (Bug #40360) * The *Note `CHECK TABLE ... FOR UPGRADE': check-table. statement did not check for incompatible collation changes made in MySQL 5.1.24 (Bug#27877). This also affects *Note `mysqlcheck': mysqlcheck. and *Note `mysql_upgrade': mysql-upgrade, which cause that statement to be executed. See *Note checking-table-incompatibilities::. Prior to this fix, a binary upgrade (performed without dumping tables with *Note `mysqldump': mysqldump. before the upgrade and reloading the dump file after the upgrade) would corrupt tables that have indexes that use the `utf8_general_ci' or `ucs2_general_ci' collation for columns that contain `'ss'' LATIN SMALL LETTER SHARP S (German). After the fix, *Note `CHECK TABLE ... FOR UPGRADE': check-table. properly detects the problem and warns about tables that need repair. However, the fix is not backward compatible and can result in a downgrading problem under these circumstances: 1. Perform a binary upgrade to a version of MySQL that includes the fix. 2. Run *Note `CHECK TABLE ... FOR UPGRADE': check-table. (or *Note `mysqlcheck': mysqlcheck. or *Note `mysql_upgrade': mysql-upgrade.) to upgrade tables. 3. Perform a binary downgrade to a version of MySQL that does not include the fix. The solution is to dump tables with *Note `mysqldump': mysqldump. before the downgrade and reload the dump file after the downgrade. Alternatively, drop and recreate affected indexes. (Bug #40053) * Some recent releases for Solaris 10 were built on Solaris 10 U5, which included a new version of `libnsl.so' that does not work on U4 or earlier. To correct this, Solaris 10 builds now are created on machines that do not have that upgraded `libnsl.so', so that they will work on Solaris 10 installations both with and without the upgraded `libnsl.so'. (Bug #39074) * With binary logging enabled, *Note `CREATE TABLE ... SELECT': create-table. and *Note `INSERT INTO ... SELECT': insert-select. failed if the source table was a log table. (Bug #34306) * XA transaction rollbacks could result in corrupted transaction states and a server crash. (Bug #28323) * *Note `ALTER TABLE': alter-table. for an *Note `ENUM': enum. column could change column values. (Bug #23113)  File: manual.info, Node: news-5-1-29, Next: news-5-1-28, Prev: news-5-1-30, Up: news-5-1-x D.1.39 Changes in MySQL 5.1.29 (11 October 2008) ------------------------------------------------ *Functionality added or changed:* * *Important Change*: The `--skip-thread-priority' option is now deprecated such that the server won't change the thread priorities by default. Giving threads different priorities might yield marginal improvements in some platforms (where it actually works), but it might instead cause significant degradation depending on the thread count and number of processors. Meddling with the thread priorities is a not a safe bet as it is very dependent on the behavior of the CPU scheduler and system where MySQL is being run. (Bug #35164, Bug #37536) * *Important Change*: The `--log' option now is deprecated and will be removed (along with the `log' system variable) in the future. Instead, use the `--general_log' option to enable the general query log and the `--general_log_file=FILE_NAME' option to set the general query log file name. The values of these options are available in the `general_log' and `general_log_file' system variables, which can be changed at runtime. Similar changes were made for the `--log-slow-queries' option and `log_slow_queries' system variable. You should use the `--slow_query_log' and `--slow_query_log_file=FILE_NAME' options instead (and the `slow_query_log' and `slow_query_log_file' system variables). * The `BUILD/compile-solaris-*' scripts now compile MySQL with the `mtmalloc' library rather than `malloc'. (Bug #38727) *Bugs fixed:* * *Incompatible Change*: *Replication*: The default binary logging mode has been changed from `MIXED' to `STATEMENT' for compatibility with MySQL 5.0. (Bug #39812) * *Incompatible Change*: *Note `CHECK TABLE ... FOR UPGRADE': check-table. did not check for incompatible collation changes made in MySQL 5.1.21 (Bug#29499) and 5.1.23 (Bug#27562, Bug#29461). This also affects *Note `mysqlcheck': mysqlcheck. and *Note `mysql_upgrade': mysql-upgrade, which cause that statement to be executed. See *Note checking-table-incompatibilities::. (Bug #39585) See also Bug #40984. * *Incompatible Change*: In connection with view creation, the server created `arc' directories inside database directories and maintained useless copies of `.frm' files there. Creation and renaming procedures of those copies as well as creation of `arc' directories has been discontinued. This change does cause a problem when downgrading to older server versions which manifests itself under these circumstances: 1. Create a view `v_orig' in MySQL 5.1.29 or higher. 2. Rename the view to `v_new' and then back to `v_orig'. 3. Downgrade to an older 5.1.x server and run *Note `mysql_upgrade': mysql-upgrade. 4. Try to rename `v_orig' to `v_new' again. This operation fails. As a workaround to avoid this problem, use either of these approaches: * Dump your data using *Note `mysqldump': mysqldump. before downgrading and reload the dump file after downgrading. * Instead of renaming a view after the downgrade, drop it and recreate it. The downgrade problem introduced by the fix for this bug has been addressed as Bug#40021. (Bug #17823) * *Important Change*: *Replication*: The `SUPER' privilege is now required to change the session value of `binlog_format' as well as its global value. For more information about `binlog_format', see *Note replication-formats::. (Bug #39106) * *Partitioning*: *Replication*: Replication to partitioned `MyISAM' tables could be slow with row-based binary logging. (Bug #35843) * *Partitioning*: If an error occurred when evaluating a column of a partitioned table for the partitioning function, the row could be inserted anyway. (Bug #38083) * *Partitioning*: Using *Note `INSERT ... SELECT': insert-select. to insert records into a partitioned `MyISAM' table could fail if some partitions were empty and others are not. (Bug #38005) * *Partitioning*: Ordered range scans on partitioned tables were not always handled correctly. In some cases this caused some rows to be returned twice. The same issue also caused `GROUP BY' query results to be aggregated incorrectly. (Bug #30573, Bug #33257, Bug #33555) * *Replication*: Server code used in binary logging could in some cases be invoked even though binary logging was not actually enabled, leading to asserts and other server errors. (Bug #38798) * *Replication*: Replication of `BLACKHOLE' tables did not work with row-based binary logging. (Bug #38360) * *Replication*: In some cases, a replication master sent a special event to a reconnecting slave to keep the slave's temporary tables, but they still had references to the `old' slave SQL thread and used them to access that thread's data. (Bug #38269) * *Replication*: Replication filtering rules were inappropiately applied when executing *Note `BINLOG': binlog. pseudo-queries. One way in which this problem showed itself was that, when replaying a binary log with *Note `mysqlbinlog': mysqlbinlog, RBR events were sometimes not executed if the `--replicate-do-db' option was specified. Now replication rules are applied only to those events executed by the slave SQL thread. (Bug #36099) * *Replication*: For a *Note `CREATE TABLE ... SELECT': create-table. statement that creates a table in a database other than the current one, the table could be created in the wrong database on replication slaves if row-based binary logging is used. (Bug #34707) * *Replication*: A statement did not always commit or roll back correctly when the server was shut down; the error could be triggered by having a failing *Note `UPDATE': update. or *Note `INSERT': insert. statement on a transactional table, causing an implicit rollback. (Bug #32709) See also Bug #38262. * The Sun Studio compiler failed to build debug versions of the server due to use of features specific to `gcc'. (Bug #39451) * For a *Note `TIMESTAMP': datetime. column in an `InnoDB' table, testing the column with multiple conditions in the `WHERE' clause caused a server crash. (Bug #39353) * References to local variables in stored procedures are replaced with `NAME_CONST(NAME, VALUE)' when written to the binary log. However, an `illegal mix of collation' error might occur when executing the log contents if the value's collation differed from that of the variable. Now information about the variable collation is written as well. (Bug #39182) * Queries of the form `SELECT ... REGEXP BINARY NULL' could lead to a hung or crashed server. (Bug #39021) * Statements of the form `INSERT ... SELECT .. ON DUPLICATE KEY UPDATE COL_NAME = DEFAULT' could result in a server crash. (Bug #39002) * Column names constructed due to wild-card expansion done inside a stored procedure could point to freed memory if the expansion was performed after the first call to the stored procedure. (Bug #38823) * Repeated *Note `CREATE TABLE ... SELECT': create-table. statements, where the created table contained an `AUTO_INCREMENT' column, could lead to an assertion failure. (Bug #38821) * For deadlock between two transactions that required a timeout to resolve, all server tables became inaccessible for the duration of the deadlock. (Bug #38804) * When inserting a string into a duplicate-key error message, the server could improperly interpret the string, resulting in a crash. (Bug #38701) * A race condition between threads sometimes caused unallocated memory to be addressed. (Bug #38692) * A server crash resulted from concurrent execution of a multiple-table *Note `UPDATE': update. that used a `NATURAL' or `USING' join together with *Note `FLUSH TABLES WITH READ LOCK': flush. or *Note `ALTER TABLE': alter-table. for the table being updated. (Bug #38691) * On ActiveState Perl, `mysql-test-run.pl --start-and-exit' started but did not exit. (Bug #38629) * An uninitialized variable in the query profiling code was corrected (detected by Valgrind). (Bug #38560) * A server crash resulted from execution of an *Note `UPDATE': update. that used a derived table together with *Note `FLUSH TABLES': flush. (Bug #38499) * Stored procedures involving substrings could crash the server on certain platforms due to invalid memory reads. (Bug #38469) * The handlerton-to-plugin mapping implementation did not free handler plugin references when the plugin was uninstalled, resulting in a server crash after several install/uninstall cycles. Also, on Mac OS X, the server crashed when trying to access an `EXAMPLE' table after the `EXAMPLE' plugin was installed. (Bug #37958) * The server crashed if an argument to a stored procedure was a subquery that returned more than one row. (Bug #37949) * When analyzing the possible index use cases, the server was incorrectly reusing an internal structure, leading to a server crash. (Bug #37943) * Access checks were skipped for *Note `SHOW PROCEDURE STATUS': show-procedure-status. and *Note `SHOW FUNCTION STATUS': show-function-status, which could lead to a server crash or insufficient access checks in subsequent statements. (Bug #37908) * The `<=>' operator could return incorrect results when comparing `NULL' to *Note `DATE': datetime, *Note `TIME': time, or *Note `DATETIME': datetime. values. (Bug #37526) * The combination of a subquery with a `GROUP BY', an aggregate function calculated outside the subquery, and a `GROUP BY' on the outer *Note `SELECT': select. could cause the server to crash. (Bug #37348) * The `NO_BACKSLASH_ESCAPES' SQL mode was ignored for *Note `LOAD DATA INFILE': load-data. and `SELECT INTO ... OUTFILE'. The setting is taken into account now. (Bug #37114) * In some cases, references to views were confused with references to anonymous tables and privilege checking was not performed. (Bug #36086) * For crash reports on Windows, symbol names in stack traces were not correctly resolved. (Bug #35987) * *Note `ALTER EVENT': alter-event. changed the `PRESERVE' attribute of an event even when `PRESERVE' was not specified in the statement. (Bug #35981) * Host name values in SQL statements were not being checked for `'@'', which is illegal according to RFC952. (Bug #35924) * *Note `mysql_install_db': mysql-install-db. failed on machines that had the host name set to `localhost'. (Bug #35754) * Dynamic plugins failed to load on i5/OS. (Bug #35743) * With the `PAD_CHAR_TO_FULL_LENGTH' SQL mode enabled, a `ucs2' *Note `CHAR': char. column returned additional garbage after trailing space characters. (Bug #35720) * A trigger for an `InnoDB' table activating multiple times could lead to `AUTO_INCREMENT' gaps. (Bug #31612) * *Note `mysqldump': mysqldump. could fail to dump views containing a large number of columns. (Bug #31434) * The server could improperly type user-defined variables used in the select list of a query. (Bug #26020) * For access to the *Note `INFORMATION_SCHEMA.VIEWS': views-table. table, the server did not check the `SHOW VIEW' and *Note `SELECT': select. privileges, leading to inconsistency between output from that table and the *Note `SHOW CREATE VIEW': show-create-view. statement. (Bug #22763) * `mysqld_safe' would sometimes fail to remove the pid file for the old `mysql' process after a crash. As a result, the server would fail to start due to a false `A mysqld process already exists...' error. (Bug #11122)  File: manual.info, Node: news-5-1-28, Next: news-5-1-27, Prev: news-5-1-29, Up: news-5-1-x D.1.40 Changes in MySQL 5.1.28 (28 August 2008) ----------------------------------------------- *Functionality added or changed:* * *Important Change*: *Note `mysqlbinlog': mysqlbinlog. now supports `--verbose' and `--base64-output=DECODE-ROWS' options to display row events as commented SQL statements. (The default otherwise is to display row events encoded as base-64 strings using *Note `BINLOG': binlog. statements.) See *Note mysqlbinlog-row-events::. (Bug #31455) * MySQL source distributions are now available in Zip format. (Bug #27742) * Added the *Note `SHOW PROFILES': show-profiles. and *Note `SHOW PROFILE': show-profile. statements to display statement profile data, and the accompanying *Note `INFORMATION_SCHEMA.PROFILING': profiling-table. table. Profiling is controlled using the `profiling' and `profiling_history_size' session variables. see *Note show-profiles::, and *Note profiling-table::. (Community contribution by Jeremy Cole) The profiling feature is enabled using the `--enable-community-features' and `--enable-profiling' options to `configure'. These options are enabled by default; to disable them, use `--disable-community-features' and `--disable-profiling'. (Bug #24795) *Bugs fixed:* * *Performance*: *Incompatible Change*: Some performance problems of *Note `SHOW ENGINE INNODB STATUS': show-engine. were reduced by removing `used cells' and `Total number of lock structs in row lock hash table' from the output. Now these values are present only if the `UNIV_DEBUG' symbol is defined at MySQL build time. (Bug #36941, Bug #36942) * *Performance*: Over-aggressive lock acquisition by `InnoDB' when calculating free space for tablespaces could result in performance degradation when multiple threads were executing statements on multi-core machines. (Bug #38185) * *Important Change*: *Security Fix*: Additional corrections were made for the symlink-related privilege problem originally addressed in MySQL 5.1.24. The original fix did not correctly handle the data directory path name if it contained symlinked directories in its path, and the check was made only at table-creation time, not at table-opening time later. *Note*: Additional fixes were made in MySQL 5.1.41. (Bug #32167, CVE-2008-2079) See also Bug #39277. * *Security Enhancement*: The server consumed excess memory while parsing statements with hundreds or thousands of nested boolean conditions (such as `OR (OR ... (OR ... ))'). This could lead to a server crash or incorrect statement execution, or cause other client statements to fail due to lack of memory. The latter result constitutes a denial of service. (Bug #38296) * *Incompatible Change*: There were some problems using `DllMain()' hook functions on Windows that automatically do global and per-thread initialization for `libmysqld.dll': * Per-thread initialization: MySQL internally counts the number of active threads, which causes a delay in `my_end()' if not all threads have exited. But there are threads that can be started either by Windows internally (often in TCP/IP scenarios) or by users. Those threads do not necessarily use `libmysql.dll' functionality but still contribute to the open-thread count. (One symptom is a five-second delay in times for PHP scripts to finish.) * Process-initialization: *Note `my_init()': my-init. calls `WSAStartup' that itself loads DLLs and can lead to a deadlock in the Windows loader. To correct these problems, DLL initialization code now is not invoked from `libmysql.dll' by default. To obtain the previous behavior (DLL initialization code will be called), set the `LIBMYSQL_DLLINIT' environment variable to any value. This variable exists only to prevent breakage of existing Windows-only applications that do not call *Note `mysql_thread_init()': mysql-thread-init. and work okay today. Use of `LIBMYSQL_DLLINIT' is discouraged and is removed in MySQL 6.0. (Bug #37226, Bug #33031) * *Incompatible Change*: *Note `SHOW STATUS': show-status. took a lot of CPU time for calculating the value of the `Innodb_buffer_pool_pages_latched' status variable. Now this variable is calculated and included in the output of *Note `SHOW STATUS': show-status. only if the `UNIV_DEBUG' symbol is defined at MySQL build time. (Bug #36600) * *Incompatible Change*: An additional correction to the original MySQL 5.1.23 fix was made to normalize directory names before adding them to the list of directories. This prevents `/etc/' and `/etc' from being considered different, for example. (Bug #20748) See also Bug #38180. * *Partitioning*: When a partitioned table had a *Note `TIMESTAMP': datetime. column defined with `CURRENT_TIMESTAMP' as the default but with no `ON UPDATE' clause, the column's value was incorrectly set to `CURRENT_TIMESTAMP' when updating across partitions. (Bug #38272) * *Partitioning*: *Note `myisamchk': myisamchk. failed with an assertion error when analyzing a partitioned `MyISAM' table. (Bug #37537) * *Partitioning*: A `LIST' partitioned `MyISAM' table returned erroneous results when an index was present on a column in the `WHERE' clause and `NOT IN' was used on that column. Searches using the index were also much slower then if the index were not present. (Bug #35931) * *Partitioning*: `SELECT COUNT(*)' was not correct for some partitioned tables using a storage engine that did not support `HA_STATS_RECORDS_IS_EXACT'. Tables using the `ARCHIVE' storage engine were known to be affected. This was because `ha_partition::records()' was not implemented, and so the default `handler::records()' was used in its place. However, this is not correct behavior if the storage engine does not support `HA_STATS_RECORDS_IS_EXACT'. The solution was to implement `ha_partition::records()' as a wrapper around the underlying partition records. As a result of this fix, the rows column in the output of *Note `EXPLAIN PARTITIONS': explain. now includes the total number of records in the partitioned table. (Bug #35745) * *Partitioning*: `MyISAM' recovery enabled with the `--myisam-recover' option did not work for partitioned `MyISAM' tables. (Bug #35161) * *Partitioning*: When one user was in the midst of a transaction on a partitioned table, a second user performing an *Note `ALTER TABLE': alter-table. on this table caused the server to hang. (Bug #34604) * *Partitioning*: Attempting to execute an *Note `INSERT DELAYED': insert-delayed. statement on a partitioned table produced the error `Table storage engine for 'TABLE' doesn't have this option', which did not reflect the source of the error accurately. The error message returned in such cases has been changed to `DELAYED option not supported for table 'TABLE''. (Bug #31210) * *Replication*: Some kinds of internal errors, such as `Out of memory' errors, could cause the server to crash when replicating statements with user variables. certain internal errors. (Bug #37150) * *Replication*: Row-based replication did not correctly copy *Note `TIMESTAMP': datetime. values from a big-endian storage engine to a little-endian storage engine. (Bug #37076) * *Replication*: *Note `INSTALL PLUGIN': install-plugin. and *Note `UNINSTALL PLUGIN': uninstall-plugin. caused row-based replication to fail. *Note*: These statements are not replicated; however, when using row-based logging, the changes they introduce in the `mysql' system tables are written to the binary log. (Bug #35807) * Server-side cursors were not initialized properly, which could cause a server crash. (Bug #38486) * A server crash or Valgrind warnings could result when a stored procedure selected from a view that referenced a function. (Bug #38291) * A failure to clean up binary log events was corrected (detected by Valgrind). (Bug #38290) * Incorrect handling of aggregate functions when loose index scan was used caused a server crash. (Bug #38195) * Queries containing a subquery with `DISTINCT' and `ORDER BY' could cause a server crash. (Bug #38191) * The fix for Bug#20748 caused a problem such that on Unix, MySQL programs looked for options in `~/my.cnf' rather than the standard location of `~/.my.cnf'. (Bug #38180) * If the table definition cache contained tables with many *Note `BLOB': blob. columns, much memory could be allocated to caching *Note `BLOB': blob. values. Now a size limit on the cached *Note `BLOB': blob. values is enforced. (Bug #38002) * For `InnoDB' tables, `ORDER BY ... DESC' sometimes returned results in ascending order. (Bug #37830) * If a table has a `BIT NOT NULL' column `c1' with a length shorter than 8 bits and some additional `NOT NULL' columns `c2', ..., and a *Note `SELECT': select. query has a `WHERE' clause of the form `(c1 = CONSTANT) AND c2 ...', the query could return an unexpected result set. (Bug #37799) * The server returned unexpected results if a right side of the `NOT IN' clause consisted of the `NULL' value and some constants of the same type. For example, this query might return 3, 4, 5, and so forth if a table contained those values: SELECT * FROM t WHERE NOT t.id IN (NULL, 1, 2); (Bug #37761) * Setting the session value of the `innodb_table_locks' system variable caused a server crash. (Bug #37669) * Nesting of `IF()' inside of `SUM()' could cause an extreme server slowdown. (Bug #37662) * Killing a query that used an `EXISTS' subquery as the argument to `SUM()' or `AVG()' caused a server crash. (Bug #37627) * When using indexed `ORDER BY' sorting, incorrect query results could be produced if the optimizer switched from a covering index to a noncovering index. (Bug #37548) * After *Note `TRUNCATE TABLE': truncate-table. for an `InnoDB' table, inserting explicit values into an `AUTO_INCREMENT' column could fail to increment the counter and result in a duplicate-key error for subsequent insertion of `NULL'. (Bug #37531) * Within stored programs or prepared statements, `REGEXP' could return incorrect results due to improper initialization. (Bug #37337) * For a `MyISAM' table with `CHECKSUM = 1' and `ROW_FORMAT = DYNAMIC' table options, a data consistency check (maximum record length) could fail and cause the table to be marked as corrupted. (Bug #37310) * The `max_length' result set metadata value was calculated incorrectly under some circumstances. (Bug #37301) * If the length of a field was 3, internal `InnoDB' to integer type conversion didn't work on big-endian machines in the `row_search_autoinc_column()' function. (Bug #36793) * A query which had an `ORDER BY DESC' clause that is satisfied with a reverse range scan could cause a server crash for some specific CPU/compiler combinations. (Bug #36639) * The `CSV' storage engine returned success even when it failed to open a table's data file. (Bug #36638) * *Note `SELECT DISTINCT': select. from a simple view on an `InnoDB' table, where all selected columns belong to the same unique index key, returned incorrect results. (Bug #36632) * Dumping information about locks in use by sending a `SIGHUP' signal to the server or by invoking the *Note `mysqladmin debug': mysqladmin. command could lead to a server crash in debug builds or to undefined behavior in production builds. (Bug #36579) * If initialization of an `INFORMATION_SCHEMA' plugin failed, *Note `INSTALL PLUGIN': install-plugin. freed some internal plugin data twice. (Bug #36399) * For `InnoDB' tables, the `DATA_FREE' column of the *Note `INFORMATION_SCHEMA.TABLES': tables-table. displayed free space in kilobytes rather than bytes. Now it displays bytes. (Bug #36278) * When the fractional part in a multiplication of *Note `DECIMAL': numeric-types. values overflowed, the server truncated the first operand rather than the longest. Now the server truncates so as to produce more precise multiplications. (Bug #36270) * The *Note `mysql': mysql. client failed to recognize comment lines consisting of `--' followed by a newline. (Bug #36244) * The server could crash with an assertion failure (or cause the client to get a `Packets out of order' error) when the expected query result was that it should terminate with a `Subquery returns more than 1 row' error. (Bug #36135) * The `UUID()' function returned UUIDs with the wrong time; this was because the offset for the time part in UUIDs was miscalculated. (Bug #35848) * The `configure' script did not permit `utf8_hungarian_ci' to be specified as the default collation. (Bug #35808) * On 64-bit systems, assigning values of 2 ^63 - 1 or larger to `key_buffer_size' caused memory overruns. (Bug #35616) * For `InnoDB' tables, *Note `REPLACE': replace. statements used `traditional' style locking, regardless of the setting of `innodb_autoinc_lock_mode'. Now *Note `REPLACE': replace. works the same way as `simple inserts' instead of using the old locking algorithm. (*Note `REPLACE': replace. statements are treated in the same way as *Note `INSERT': insert. statements.) (Bug #35602) * Freeing of an internal parser stack during parsing of complex stored programs caused a server crash. (Bug #35577, Bug #37269, Bug #37228) * *Note `mysqlbinlog': mysqlbinlog. left temporary files on the disk after shutdown, leading to the pollution of the temporary directory, which eventually caused *Note `mysqlbinlog': mysqlbinlog. to fail. This caused problems in testing and other situations where *Note `mysqlbinlog': mysqlbinlog. might be invoked many times in a relatively short period of time. (Bug #35543) * Index scans performed with the `sort_union()' access method returned wrong results, caused memory to be leaked, and caused temporary files to be deleted when the limit set by `sort_buffer_size' was reached. (Bug #35477, Bug #35478) * Table checksum calculation could cause a server crash for `FEDERATED' tables with *Note `BLOB': blob. columns containing `NULL' values. (Bug #34779) * A significant slowdown occurred when many *Note `SELECT': select. statements that return many rows from `InnoDB' tables were running concurrently. (Bug #34409) * *Note `mysql_install_db': mysql-install-db. failed if the server was running with an SQL mode of `TRADITIONAL'. This program now resets the SQL mode internally to avoid this problem. (Bug #34159) * Changes to build files were made to enable the MySQL distribution to compile on Microsoft Visual C++ Express 2008. (Bug #33907) * Fast *Note `ALTER TABLE': alter-table. operations were not fast for columns that used multibyte character sets. (Bug #33873) * The internal functions `my_getsystime()', `my_micro_time()', and `my_micro_time_and_time()' did not work correctly on Windows. One symptom was that uniqueness of `UUID()' values could be compromised. (Bug #33748) * Cached queries that used 256 or more tables were not properly cached, so that later query invalidation due to a *Note `TRUNCATE TABLE': truncate-table. for one of the tables caused the server to hang. (Bug #33362) * *Note `mysql_upgrade': mysql-upgrade. attempted to use the `/proc' file system even on systems that do not have it. (Bug #31605) * *Note `mysql_install_db': mysql-install-db. failed if the default storage engine was *Note `NDB': mysql-cluster. Now it explicitly uses `MyISAM' as the storage engine when running *Note `mysqld --bootstrap': mysqld. (Bug #31315) * Several MySQL programs could fail if the `HOME' environment variable had an empty value. (Bug #30394) * On NetWare, *Note `mysql_install_db': mysql-install-db. could appear to execute normally even if it failed to create the initial databases. (Bug #30129) * The Serbian translation for the `ER_INCORRECT_GLOBAL_LOCAL_VAR' error was corrected. (Bug #29738) * *Note `TRUNCATE TABLE': truncate-table. for `InnoDB' tables returned a count showing too many rows affected. Now the statement returns 0 for `InnoDB' tables. (Bug #29507) * The `BUILD/check-cpu' build script failed if `gcc' had a different name (such as `gcc.real' on Debian). (Bug #27526) * In some cases, the parser interpreted the `;' character as the end of input and misinterpreted stored program definitions. (Bug #26030) * The *Note `FLUSH PRIVILEGES': flush. statement did not produce an error when it failed. (Bug #21226) * After executing a prepared statement that accesses a stored function, the next execution would fail to find the function if the stored function cache was flushed in the meantime. (Bug #12093, Bug #21294)  File: manual.info, Node: news-5-1-27, Next: news-5-1-26, Prev: news-5-1-28, Up: news-5-1-x D.1.41 Changes in MySQL 5.1.27 (Not released) --------------------------------------------- *Functionality added or changed:* * `mysqltest' now installs signal handlers and generates a stack trace if it crashes. (Bug #37003) * `mysql-test-run.pl' now supports `--client-bindir' and `--client-libdir' options for specifying the directory where client binaries and libraries are located. (Bug #34995) *Bugs fixed:* * *Partitioning*: *Incompatible Change*: On Mac OS X, with `lower_case_table_names = 2', the server could not read partitioned tables whose names contained uppercase letters. Partitioned tables using mixed case names should be renamed or dropped before upgrading to this version of the server on Mac OS X. (Bug #37402) * *Important Change*: *Partitioning*: The statements *Note `ANALYZE TABLE': analyze-table, *Note `CHECK TABLE': check-table, *Note `OPTIMIZE TABLE': optimize-table, and *Note `REPAIR TABLE': repair-table. are now supported for partitioned tables. Also as a result of this fix, the following statements which were disabled in MySQL 5.1.24 have been re-enabled: * `ALTER TABLE ... ANALYZE PARTITION' * `ALTER TABLE ... CHECK PARTITION' * `ALTER TABLE ... OPTIMIZE PARTITION' * `ALTER TABLE ... REPAIR PARTITION' (Bug #20129) See also Bug #39434. * *Replication*: Issuing a *Note `DROP DATABASE': drop-database. while any temporary tables were open caused the server to switch to statement-based mode. (Bug #38773) * *Replication*: The `--replicate-*-table' options were not evaluated correctly when replicating multi-table updates. As a result of this fix, replication of multi-table updates no longer fails when an update references a missing table but does not update any of its columns. (Bug #37051) * The fix for Bug#33812 had the side effect of causing the *Note `mysql': mysql. client not to be able to read some dump files produced with *Note `mysqldump': mysqldump. To address this, that fix was reverted. (Bug #38158)  File: manual.info, Node: news-5-1-26, Next: news-5-1-25, Prev: news-5-1-27, Up: news-5-1-x D.1.42 Changes in MySQL 5.1.26 (30 June 2008) --------------------------------------------- *Functionality added or changed:* * *Important Change*: *Incompatible Change*: The `FEDERATED' storage engine is now disabled by default in binary distributions. The engine is still available and can be enabled by starting the server with the `--federated' option. (Bug #37069) * `mysqltest' was changed to be more robust in the case of a race condition that can occur for rapid disconnect/connect sequences with the server. The account used by `mysqltest' could reach its permitted simultaneous-sessions user limit if the connect attempt occurred before the server had fully processed the preceding disconnect. `mysqltest' now checks specificaly for a user-limits error when it connects; if that error occurs, it delays briefly before retrying. (Bug #23921) *Bugs fixed:* * *Replication*: Row-based replication broke for `utf8' *Note `CHAR': char. columns longer than 85 characters. (Bug #37426) * *Replication*: Performing an insert on a table having an `AUTO_INCREMENT' column and an *Note `INSERT': insert. trigger that was being replicated from a master running MySQL 5.0 or any version of MySQL 5.1 up to and including MySQL 5.1.11 to a slave running MySQL 5.1.12 or later caused the replication slave to crash. (Bug #36443) See also Bug #33029. * Some binary distributions had a duplicate `-64bit' suffix in the file name. (Bug #37623) * `NOT IN' subqueries that selected `MIN()' or `MAX()' values but produced an empty result could cause a server crash. (Bug #37004) * `ha_innodb.so' was incorrectly installed in the `lib/mysql' directory rather than in `lib/mysql/plugin'. (Bug #36434) * An empty bit-string literal (`b''') caused a server crash. Now the value is parsed as an empty bit value (which is treated as an empty string in string context or 0 in numeric context). (Bug #35658) * The code for detecting a byte order mark (BOM) caused *Note `mysql': mysql. to crash for empty input. (Bug #35480) * The *Note `mysql': mysql. client incorrectly parsed statements containing the word `delimiter' in mid-statement. The fix for this bug had the side effect of causing the problem reported in Bug#38158, so it was reverted in MySQL 5.1.27. (Bug #33812)  File: manual.info, Node: news-5-1-25, Next: news-5-1-24, Prev: news-5-1-26, Up: news-5-1-x D.1.43 Changes in MySQL 5.1.25 (28 May 2008) -------------------------------------------- *Functionality added or changed:* * *Incompatible Change*: A change has been made to the way that the server handles prepared statements. This affects prepared statements processed at the SQL level (using the *Note `PREPARE': prepare. statement) and those processed using the binary client/server protocol (using the *Note `mysql_stmt_prepare()': mysql-stmt-prepare. C API function). Previously, changes to metadata of tables or views referred to in a prepared statement could cause a server crash when the statement was next executed, or perhaps an error at execute time with a crash occurring later. For example, this could happen after dropping a table and recreating it with a different definition. Now metadata changes to tables or views referred to by prepared statements are detected and cause automatic repreparation of the statement when it is next executed. Metadata changes occur for DDL statements such as those that create, drop, alter, rename, or truncate tables, or that analyze, optimize, or repair tables. Repreparation also occurs after referenced tables or views are flushed from the table definition cache, either implicitly to make room for new entries in the cache, or explicitly due to *Note `FLUSH TABLES': flush. Repreparation is automatic, but to the extent that it occurs, performance of prepared statements is diminished. Table content changes (for example, with *Note `INSERT': insert. or *Note `UPDATE': update.) do not cause repreparation, nor do *Note `SELECT': select. statements. An incompatibility with previous versions of MySQL is that a prepared statement may now return a different set of columns or different column types from one execution to the next. For example, if the prepared statement is `SELECT * FROM t1', altering `t1' to contain a different number of columns causes the next execution to return a number of columns different from the previous execution. Older versions of the client library cannot handle this change in behavior. For applications that use prepared statements with the new server, an upgrade to the new client library is strongly recommended. Along with this change to statement repreparation, the default value of the `table_definition_cache' system variable has been increased from 128 to 256. The purpose of this increase is to lessen the chance that prepared statements will need repreparation due to referred-to tables/views having been flushed from the cache to make room for new entries. A status variable, `Com_stmt_reprepare', has been introduced to track the number of repreparations. (Bug #27420, Bug #27430, Bug #27690) * *Important Change*: Some changes were made to *Note `CHECK TABLE ... FOR UPGRADE': check-table. and *Note `REPAIR TABLE': repair-table. with respect to detection and handling of tables with incompatible `.frm' files (files created with a different version of the MySQL server). These changes also affect *Note `mysqlcheck': mysqlcheck. because that program uses *Note `CHECK TABLE': check-table. and *Note `REPAIR TABLE': repair-table, and thus also *Note `mysql_upgrade': mysql-upgrade. because that program invokes *Note `mysqlcheck': mysqlcheck. * If your table was created by a different version of the MySQL server than the one you are currently running, *Note `CHECK TABLE ... FOR UPGRADE': check-table. indicates that the table has an `.frm' file with an incompatible version. In this case, the result set returned by *Note `CHECK TABLE': check-table. contains a line with a `Msg_type' value of `error' and a `Msg_text' value of `Table upgrade required. Please do "REPAIR TABLE `TBL_NAME`" to fix it!' * *Note `REPAIR TABLE': repair-table. without `USE_FRM' upgrades the `.frm' file to the current version. * If you use `REPAIR TABLE ...USE_FRM' and your table was created by a different version of the MySQL server than the one you are currently running, *Note `REPAIR TABLE': repair-table. will not attempt to repair the table. In this case, the result set returned by *Note `REPAIR TABLE': repair-table. contains a line with a `Msg_type' value of `error' and a `Msg_text' value of `Failed repairing incompatible .FRM file'. Previously, use of `REPAIR TABLE ...USE_FRM' with a table created by a different version of the MySQL server risked the loss of all rows in the table. (Bug #36055) * *Note `mysql_upgrade': mysql-upgrade. now has a `--tmpdir' option to enable the location of temporary files to be specified. (Bug #36469) * *Note `mysqldump': mysqldump. now adds the `LOCAL' qualifier to the *Note `FLUSH TABLES': flush. statement that is sent to the server when the `--master-data' option is enabled. This prevents the *Note `FLUSH TABLES': flush. statement from replicating to slaves, which is disadvantageous because it would cause slaves to block while the statement executes. (Bug #35157) See also Bug #38303. *Bugs fixed:* * *Important Change*: The server no longer issues warnings for truncation of excess spaces for values inserted into *Note `CHAR': char. columns. This reverts a change in the previous release that caused warnings to be issued. (Bug #30059) * *Replication*: *Note `CREATE PROCEDURE': create-procedure. and *Note `CREATE FUNCTION': create-function. statements containing extended comments were not written to the binary log correctly, causing parse errors on the slave. (Bug #36570) See also Bug #32575. * *Replication*: When flushing tables, there was a slight chance that the flush occurred between the processing of one table map event and the next. Since the tables were opened one by one, subsequent locking of tables would cause the slave to crash. This problem was observed when replicating *Note `NDBCLUSTER': mysql-cluster. or `InnoDB' tables, when executing multi-table updates, and when a trigger or a stored routine performed an (additional) insert on a table so that two tables were effectively being inserted into in the same statement. (Bug #36197) * *Replication*: *Note `CREATE VIEW': create-view. statements containing extended comments were not written to the binary log correctly, causing parse errors on the slave. Now, all comments are stripped from such statements before being written to the binary log. (Bug #32575) See also Bug #36570. * On Windows 64-bit systems, temporary variables of `long' types were used to store `ulong' values, causing key cache initialization to receive distorted parameters. The effect was that setting `key_buffer_size' to values of 2GB or more caused memory exhaustion to due allocation of too much memory. (Bug #36705) * Multiple-table *Note `UPDATE': update. statements that used a temporary table could fail to update all qualifying rows or fail with a spurious duplicate-key error. (Bug #36676) * A `REGEXP' match could return incorrect rows when the previous row matched the expression and used `CONCAT()' with an empty string. (Bug #36488) * `mysqltest' ignored the value of `--tmpdir' in one place. (Bug #36465) * When updating an existing instance (for example, from MySQL 5.0 to 5.1, or 5.1 to 6.0), the Instance Configuration Wizard unnecessarily prompted for a `root' password when there was an existing `root' password. (Bug #36305) * Conversion of a `FLOAT ZEROFILL' value to string could cause a server crash if the value was `NULL'. (Bug #36139) * On Windows, the installer attempted to use JScript to determine whether the target data directory already existed. On Windows Vista x64, this resulted in an error because the installer was attempting to run the JScript in a 32-bit engine, which wasn't registered on Vista. The installer no longer uses JScript but instead relies on a native WiX command. (Bug #36103) * `mysqltest' was performing escape processing for the `--replace_result' command, which it should not have been. (Bug #36041) * An error in calculation of the precision of zero-length items (such as `NULL') caused a server crash for queries that employed temporary tables. (Bug #36023) * For *Note `EXPLAIN EXTENDED': explain, execution of an uncorrelated `IN' subquery caused a crash if the subquery required a temporary table for its execution. (Bug #36011) * The *Note `MERGE': merge-storage-engine. storage engine did a table scan for `SELECT COUNT(*)' statements when it could calculate the number of records from the underlying tables. (Bug #36006) * The server crashed inside `NOT IN' subqueries with an impossible `WHERE' or `HAVING' clause, such as `NOT IN (SELECT ... FROM t1, t2, ... WHERE 0)'. (Bug #36005) * The Event Scheduler was not designed to work under the embedded server. It is now disabled for the embedded server, and the `event_scheduler' system variable is not displayed. (Bug #35997) * Grouping or ordering of long values in unindexed *Note `BLOB': blob. or *Note `TEXT': blob. columns with the `gbk' or `big5' character set crashed the server. (Bug #35993) * `SET GLOBAL debug=''' resulted in a Valgrind warning in `DbugParse()', which was reading beyond the end of the control string. (Bug #35986) * The `prefer full scan on clustered primary key over full scan of any secondary key' optimizer rule introduced by Bug#26447 caused a performance regression for some queries, so it has been disabled. (Bug #35850) * The server ignored any covering index used for `ref' access of a table in a query with `ORDER BY' if this index was incompatible with the `ORDER BY' list and there was another covering index compatible with this list. As a result, suboptimal execution plans were chosen for some queries that used an `ORDER BY' clause. (Bug #35844) * *Note `mysql_upgrade': mysql-upgrade. did not properly update the `mysql.event' table. (Bug #35824) * An incorrect error and message was produced for attempts to create a `MyISAM' table with an index (`.MYI') file name that was already in use by some other `MyISAM' table that was open at the same time. For example, this might happen if you use the same value of the `INDEX DIRECTORY' table option for tables belonging to different databases. (Bug #35733) * Enabling the `read_only' system variable while `autocommit' mode was enabled caused *Note `SELECT': select. statements for transactional storage engines to fail. (Bug #35732) * The combination of `GROUP_CONCAT()', `DISTINCT', and `LEFT JOIN' could crash the server when the right table is empty. (Bug #35298) * Some binaries produced stack corruption messages due to being built with versions of `bison' older than 2.1. Builds are now created using `bison' 2.3. (Bug #34926) * The `log_output' system variable could be set to an illegal value. (Bug #34820) * On Windows 64-bit builds, an apparent compiler bug caused memory overruns for code in `innobase/mem/*'. Removed optimizations so as not to trigger this problem. (Bug #34297) * Several additional configuration scripts in the `BUILD' directory now are included in source distributions. These may be useful for users who wish to build MySQL from source. (See *Note installing-development-tree::, for information about what they do.) (Bug #34291) * Executing a *Note `FLUSH PRIVILEGES': flush. statement after creating a temporary table in the `mysql' database with the same name as one of the MySQL system tables caused the server to crash. *Note*: While it is possible to shadow a system table in this way, the temporary table exists only for the current user and connection, and does not effect any user privileges. (Bug #33275) * *Note `UNION': union. constructs cannot contain *Note `SELECT ... INTO': select. except in the final *Note `SELECT': select. However, if a *Note `UNION': union. was used in a subquery and an `INTO' clause appeared in the top-level query, the parser interpreted it as having appeared in the *Note `UNION': union. and raised an error. (Bug #32858) * Assignment of relative path names to `general_log_file' or `slow_query_log_file' did not always work. (Bug #32748) * The `mysql.servers' table was not created during installation on Windows. (Bug #28680, Bug #32797) * The `jp' test suite was not working. (Bug #28563) * The internal `init_time()' library function was renamed to `my_init_time()' to avoid conflicts with external libraries. (Bug #26294) * The parser used signed rather than unsigned values in some cases that caused legal lengths in column declarations to be rejected. (Bug #15776)  File: manual.info, Node: news-5-1-24, Next: news-5-1-23, Prev: news-5-1-25, Up: news-5-1-x D.1.44 Changes in MySQL 5.1.24 (08 April 2008) ---------------------------------------------- *Functionality added or changed:* * *Important Change*: *MySQL Cluster*: *Packaging*: Beginning with this release, standard MySQL 5.1 binaries are no longer built with support for the *Note `NDBCLUSTER': mysql-cluster. storage engine, and the *Note `NDBCLUSTER': mysql-cluster. code included in 5.1 mainline sources is no longer guaranteed to be maintained or supported. Those using MySQL Cluster in MySQL 5.1.23 and earlier MySQL 5.1 mainline releases should upgrade to MySQL Cluster NDB 6.2.15 or a later MySQL Cluster NDB 6.2 or 6.3 release. (Bug #36193) * *Important Change*: The `FEDERATED' storage engine is not included in binary distributions of MySQL 5.1.24. (It will be included again in 5.1.25.) * *Replication*: Introduced the `slave_exec_mode' system variable to control whether idempotent or strict mode is used for replication conflict resolution. Idempotent mode suppresses duplicate-key, no-key-found, and some other errors, and is needed for circular replication, multi-master replication, and some other complex replication setups when using MySQL Cluster, where idempotent mode is the default. However, strict mode is the default for storage engines other than *Note `NDB': mysql-cluster. (Bug #31609) * *Replication*: When running the server with `--binlog-format=MIXED' or `--binlog-format=STATEMENT', a query that referred to a system variable used the slave's value when replayed on the slave. This meant that, if the value of a system variable was inserted into a table, the slave differed from the master. Now, statements that refer to a system variable are marked as `unsafe', which means that: * When the server is using `--binlog-format=MIXED', the row-based format is used automatically to replicate these statements. * When the server is using `--binlog-format=STATEMENT', these statements produce a warning. (Bug #31168) See also Bug #34732. * The `PROCESS' privilege now is required to start or stop the `InnoDB' monitor tables (see *Note innodb-monitors::). Previously, no privilege was required. (Bug #34053) * For binary `.tar.gz' packages, *Note `mysqld': mysqld. and other binaries now are compiled with debugging symbols included to enable easier use with a debugger. If you do not need debugging symbols and are short on disk space, you can use `strip' to remove the symbols from the binaries. (Bug #33252) * Formerly, when the MySQL server crashed, the generated stack dump was numeric and required external tools to properly resolve the names of functions. This is not very helpful to users having a limited knowledge of debugging techniques. In addition, the generated stack trace contained only the names of functions and was formatted differently for each platform due to different stack layouts. Now it is possible to take advantage of newer versions of the GNU C Library provide a set of functions to obtain and manipulate stack traces from within the program. On systems that use the ELF binary format, the stack trace contains important information such as the shared object where the call was generated, an offset into the function, and the actual return address. Having the function name also makes possible the name demangling of C++ functions. The library generates meaningful stack traces on the following platforms: i386, x86_64, PowerPC, IA64, Alpha, and S390. On other platforms, a numeric stack trace is still produced, and the use of the *Note `resolve_stack_dump': resolve-stack-dump. utility is still required. (Bug #31891) * `mysqltest' now has `mkdir' and `rmdir' commands for creating and removing directories. (Bug #31004) * The server uses less memory when loading privileges containing table grants. (Patch provided by Google.) (Bug #25175) * Added the `Uptime_since_flush_status' status variable, which indicates the number of seconds since the most recent `FLUSH STATUS' statement. (Community contribution by Jeremy Cole) (Bug #24822) * *Note `SHOW OPEN TABLES': show-open-tables. now supports `FROM' and `LIKE' clauses. (Bug #12183) * The new read-only global system variables `report_host', `report_password', `report_port', and `report_user' system variables provide runtime access to the values of the corresponding `--report-host', `--report-password', `--report-port', and `--report-user' options. * Formerly it was possible to specify an `innodb_flush_method' value of `fdatasync' to obtain the default flush behavior of using `fdatasync()' for flushing. This is no longer possible because it can be confusing that a value of `fdatasync' causes use of `fsync()' rather than `fdatasync()'. * The use of `InnoDB' hash indexes now can be controlled by setting the new `innodb_adaptive_hash_index' system variable at server startup. By default, this variable is enabled. See *Note innodb-adaptive-hash::. *Bugs fixed:* * *Performance*: `InnoDB' adaptive hash latches could be held too long during filesort operations, resulting in a server crash. Now the hash latch is released when a query on `InnoDB' tables performs a filesort. This eliminates the crash and may provide significant performance improvements on systems on which many queries using filesorts with temporary tables are being performed. (Bug #32149) * *Performance*: `InnoDB' exhibited thread thrashing with more than 50 concurrent connections under an update-intensive workload. (Bug #22868) * *Important Change*: *Security Fix*: It was possible to circumvent privileges through the creation of `MyISAM' tables employing the `DATA DIRECTORY' and `INDEX DIRECTORY' options to overwrite existing table files in the MySQL data directory. Use of the MySQL data directory in `DATA DIRECTORY' and `INDEX DIRECTORY' is no longer permitted. This is now also true of these options when used with partitioned tables and individual partitions of such tables. *Note*: Additional fixes were made in MySQL 5.1.28, 5.1.41. (Bug #32167, CVE-2008-2079) See also Bug #39277. * *Security Fix*: A client that connects to a malicious server could be tricked by the server into sending files from the client host to the server. This occurs because the `libmysqlclient' client library would respond to a `FETCH LOCAL FILE' request from the server even if the request is sent for statements from the client other than *Note `LOAD DATA LOCAL INFILE': load-data. The client library has been modified to respond to a `FETCH LOCAL FILE' request from the server only if is sent in response to a *Note `LOAD DATA LOCAL INFILE': load-data. statement from the client. The client library now also checks whether `CLIENT_LOCAL_FILE' is set and refuses to send a local file if not. *Note*: Binary distributions ship with the `local-infile' capability enabled. Applications that do not use this functionality should disable it to be safe. (Bug #29605) * *Important Change*: *Security Enhancement*: On Windows Vista and Windows Server 2008, a user without administrative privileges does not have write permissions to the `Program Files' directory where MySQL and the associated data files are normally installed. Using data files located in the standard `Program Files' installation directory could therefore cause MySQL to fail, or lead to potential security issues in an installed instance. To address the problem, on Windows XP, Windows Vista and Windows Server 2008, the datafiles and data file configuration are now set to the Microsoft recommended `AppData' folder. The `AppData' folder is typically located within the user's home directory. *Important*: When upgrading an existing 5.1.23 or 6.0.4 installation of MySQL you must take a backup of your data and configuration file (`my.ini' before installing the new version. To migrate your data, either extract the data and re-import (using *Note `mysqldump': mysqldump, then upgrade and re-import using *Note `mysql': mysql.), or back up your data, upgrade to the new version, and copy your existing data files from your old `datadir' directory to the new directory located within `AppData'. Failure to back up your data and follow these procedures may lead to data loss. (Bug #34593) * *Incompatible Change*: In MySQL 5.1.23, the `last_errno' and `last_error' members of the `NET' structure in `mysql_com.h' were renamed to `client_last_errno' and `client_last_error'. This was found to cause problems for connectors that use the internal `NET' structure for error handling. The change has been reverted. (Bug #34655) See also Bug #12713. * *Incompatible Change*: It was possible to use `FRAC_SECOND' as a synonym for `MICROSECOND' with `DATE_ADD()', `DATE_SUB()', and `INTERVAL'; now, using `FRAC_SECOND' with anything other than `TIMESTAMPADD()' or `TIMESTAMPDIFF()' produces a syntax error. It is now possible (and preferable) to use `MICROSECOND' with `TIMESTAMPADD()' and `TIMESTAMPDIFF()', and `FRAC_SECOND' is now deprecated. (Bug #33834) * *Incompatible Change*: The *Note `UPDATE': update. statement permitted `NULL' to be assigned to `NOT NULL' columns (the implicit default value for the column data type was assigned). This was changed so that on error occurs. This change was reverted, because the original report was determined not to be a bug: Assigning `NULL' to a `NOT NULL' column in an *Note `UPDATE': update. statement should produce an error only in strict SQL mode and set the column to the implicit default with a warning otherwise, which was the original behavior. See *Note data-type-defaults::, and Bug#39265. (Bug #33699) * *Incompatible Change*: For packages that are built within their own prefix (for example, `/usr/local/mysql') the plugin directory will be `lib/plugin'. For packages that are built to be installed into a system-wide prefix (such as RPM packages with a prefix of `/usr'), the plugin directory will be `lib/mysql/plugin' to ensure a clean `/usr/lib' hierarchy. In both cases, the `$pkglibdir' configuration setting is used at build time to set the plugin directory. The current plugin directory location is available as the value of the `plugin_dir' system variable as before, but the *Note `mysql_config': mysql-config. script now has a `--plugindir' option that can be used externally to the server by third-party plugin writers to obtain the default plugin directory path name and configure their installation directory appropriately. (Bug #31736) * *Incompatible Change*: The `-', `*', and `/' operators and the functions `POW()' and `EXP()' could misbehave when used with floating-point numbers. Previously they might return `+INF', `-INF', or `NaN' in cases of numeric overflow (including that caused by division by zero) or when invalid arguments were used. Now `NULL' is returned in all such cases. (Bug #31236) * *Incompatible Change*: The `utf8_general_ci' and `ucs2_general_ci' collations did not sort the letter "U+00DF SHARP S" equal to `'s''. As a result of this bug fix, indexes must be rebuilt for columns that use the `utf8_general_ci' or `ucs2_general_ci' collation for columns that contain SHARP S. See *Note checking-table-incompatibilities::. (Bug #27877) See also Bug #37046. * *Important Change*: *Partitioning*: The following statements did not function correctly with corrupted or crashed tables and have been disabled: * `ALTER TABLE ... ANALYZE PARTITION' * `ALTER TABLE ... CHECK PARTITION' * `ALTER TABLE ... OPTIMIZE PARTITION' * `ALTER TABLE ... REPAIR PARTITION' `ALTER TABLE ... REBUILD PARTITION' is unaffected by this change and continues to be available. This statement and `ALTER TABLE ... REORGANIZE PARTITION' may be used to analyze and optimize partitioned tables, since these operations cause the partition files to be rebuilt. (Bug #20129) See also Bug #39434. * *Important Change*: *Replication*: When the master crashed during an update on a transactional table while in `autocommit' mode, the slave failed. This fix causes every transaction (including `autocommit' transactions) to be recorded in the binary log as starting with a *Note `BEGIN': commit. and ending with a *Note `COMMIT': commit. or *Note `ROLLBACK': commit. *Note*: The current fix does _not_ cause nontransactional changes to be wrapped in *Note `BEGIN': commit ... *Note `COMMIT': commit. or *Note `BEGIN': commit ... *Note `ROLLBACK': commit. when written to the binary log. For this purpose, any statements affecting tables using a nontransactional storage engine such as *Note `MyISAM': myisam-storage-engine. are regarded as nontransactional, even when `autocommit' is enabled. (Bug #26395) See also Bug #29288, Bug #49522. * *Important Change*: `InnoDB' free space information is now shown in the `Data_free' column of *Note `SHOW TABLE STATUS': show-table-status. and in the `DATA_FREE' column of the *Note `INFORMATION_SCHEMA.TABLES': tables-table. table. (Bug #32440) See also Bug #11379. * *Important Change*: The server handled truncation of values having excess trailing spaces into *Note `CHAR': char, *Note `VARCHAR': char, and *Note `TEXT': blob. columns in different ways. This behavior has now been made consistent for columns of all three of these types, and now follows the existing behavior of *Note `VARCHAR': char. columns in this regard; that is, a `Note' is always issued whenever such truncation occurs. This change does not affect columns of these three types when using a binary encoding; *Note `BLOB': blob. columns are also unaffected by the change, since they always use a binary encoding. (Bug #30059) * *Important Change*: An `AFTER UPDATE' trigger was not invoked when the *Note `UPDATE': update. did not make any changes to the table for which the trigger was defined. Now `AFTER UPDATE' triggers behave the same in this regard as do `BEFORE UPDATE' triggers, which are invoked whether the *Note `UPDATE': update. makes any changes in the table or not. (Bug #23771) * *Replication*: *Important Note*: Network timeouts between the master and the slave could result in corruption of the relay log. This fix rectifies a long-standing replication issue when using unreliable networks, including replication over wide area networks such as the Internet. If you experience reliability issues and see many `You have an error in your SQL syntax' errors on replication slaves, we strongly recommend that you upgrade to a MySQL version which includes this fix. (Bug #26489) * *Partitioning*: In some cases, matching rows from a partitioned `MyISAM' using a *Note `BIT': numeric-types. column as the primary key were not found by queries. (Bug #34358) * *Partitioning*: Enabling `innodb_file_per_table' produced problems with partitioning and tablespace operations on partitioned `InnoDB' tables, in some cases leading to corrupt partitions or causing the server to crash. (Bug #33429) * *Partitioning*: A table defined using `PARTITION BY KEY' and having a *Note `BIT': numeric-types. column referenced in the partitioning key did not behave correctly; some rows could be inserted into the wrong partition, causing wrong results to be returned from queries. (Bug #33379) * *Partitioning*: For `InnoDB' tables, there was a race condition involving the data dictionary and repartitioning. (Bug #33349) * *Partitioning*: When `ALTER TABLE DROP PARTITION' was executed on a table on which there was a trigger, the statement failed with an error. This occurred even if the trigger did not reference any tables. (Bug #32943) * *Partitioning*: Currently, all partitions of a partitioned table must use the same storage engine. One may optinally specify the storage engine on a per-partition basis; however, where this is the done, the storage engine must be the same as used by the table as a whole. *Note `ALTER TABLE': alter-table. did not enforce these rules correctly, the result being that incaccurate error messages were shown when trying to use the statement to change the storage engine used by an individual partition or partitions. (Bug #31931) * *Partitioning*: Using the `DATA DIRECTORY' and `INDEX DIRECTORY' options for partitions with *Note `CREATE TABLE': create-table. or *Note `ALTER TABLE': alter-table. statements appeared to work on Windows, although they are not supported by MySQL on Windows systems, and subsequent attempts to use the tables referenced caused errors. Now these options are disabled on Windows, and attempting to use them generates a warning. (Bug #30459) * *Replication*: The failure of a `CREATE TABLE ... ENGINE=InnoDB ... SELECT' statement caused the slave to lose data. (Bug #35762) * *Replication*: When using row-based replication, a slave could crash at startup because it received a row-based replication event that `InnoDB' could not handle due to an incorrect test of the query string provided by MySQL, which was `NULL' for row-based replication events. (Bug #35226) * *Replication*: `insert_id' was not written to the binary log for inserts into `BLACKHOLE' tables. (Bug #35178) * *Replication*: When using statement-based replication and a *Note `DELETE': delete, *Note `UPDATE': update, or *Note `INSERT ... SELECT': insert-select. statement using a `LIMIT' clause is encountered, a warning that the statement is not safe to replicate in statement mode is now issued; when using `MIXED' mode, the statement is now replicated using the row-based format. (Bug #34768) * *Replication*: *Note `mysqlbinlog': mysqlbinlog. did not output the values of `auto_increment_increment' and `auto_increment_offset' when both were equal to their default values (for both of these variables, the default is 1). This meant that a binary log recorded by a client using the defaults for both variables and then replayed on another client using its own values for either or both of these variables produced erroneous results. (Bug #34732) See also Bug #31168. * *Replication*: When the Windows version of *Note `mysqlbinlog': mysqlbinlog. read 4.1 binlogs containing *Note `LOAD DATA INFILE': load-data. statements, it output backslashes as path separators, causing problems for client programs expecting forward slashes. In such cases, it now converts `\\' to `/' in directory paths. (Bug #34355) * *Replication*: *Note `SHOW SLAVE STATUS': show-slave-status. failed when slave I/O was about to terminate. (Bug #34305) * *Replication*: The character sets and collations used for constant identifiers in stored procedures were not replicated correctly. (Bug #34289) * *Replication*: *Note `mysqlbinlog': mysqlbinlog. from a 5.1 or later MySQL distribution could not read binary logs generated by a 4.1 server when the logs contained *Note `LOAD DATA INFILE': load-data. statements. (Bug #34141) This regression was introduced by Bug #32407. * *Replication*: A *Note `CREATE USER': create-user, *Note `DROP USER': drop-user, or *Note `RENAME USER': rename-user. statement that fails on the master, or that is a duplicate of any of these statements, is no longer written to the binlog; previously, either of these occurrences could cause the slave to fail. (Bug #33862) See also Bug #29749. * *Replication*: *Note `SHOW BINLOG EVENTS': show-binlog-events. could fail when the binlog contained one or more events whose size was close to the value of `max_allowed_packet'. (Bug #33413) * *Replication*: An extraneous *Note `ROLLBACK': commit. statement was written to the binary log by a connection that did not use any transactional tables. (Bug #33329) * *Replication*: *Note `mysqlbinlog': mysqlbinlog. failed to release all of its memory after terminating abnormally. (Bug #33247) * *Replication*: When a stored routine or trigger, running on a master that used MySQL 5.0 or MySQL 5.1.11 or earlier, performed an insert on an `AUTO_INCREMENT' column, the `insert_id' value was not replicated correctly to a slave running MySQL 5.1.12 or later (including any MySQL 6.0 release). (Bug #33029) See also Bug #19630. * *Replication*: The error message generated due to lack of a default value for an extra column was not sufficiently informative. (Bug #32971) * *Replication*: When a user variable was used inside an *Note `INSERT': insert. statement, the corresponding binlog event was not written to the binlog correctly. (Bug #32580) * *Replication*: When using row-based replication, deletes from a table with a foreign key constraint failed on the slave. (Bug #32468) * *Replication*: The `--base64-output' option for *Note `mysqlbinlog': mysqlbinlog. was not honored for all types of events. This interfered in some cases with performing point-in-time recovery. (Bug #32407) See also Bug #46640, Bug #34777. * *Replication*: SQL statements containing comments using `--' syntax were not replayable by *Note `mysqlbinlog': mysqlbinlog, even though such statements replicated correctly. (Bug #32205) * *Replication*: When using row-based replication from a master running MySQL 5.1.21 or earlier to a slave running 5.1.22 or later, updates of integer columns failed on the slave with `Error in Unknown event: row application failed'. (Bug #31583) This regression was introduced by Bug #21842. * *Replication*: Replicating write, update, or delete events from a master running MySQL 5.1.15 or earlier to a slave running 5.1.16 or later caused the slave to crash. (Bug #31581) * *Replication*: When using row-based replication, the slave stopped when attempting to delete nonexistent rows from a slave table without a primary key. In addition, no error was reported when this occurred. (Bug #31552) * *Replication*: Errors due to server ID conflicts were reported only in the slave's error log; now these errors are also shown in the `Server_IO_State' column in the output of *Note `SHOW SLAVE STATUS': show-slave-status. (Bug #31316) * *Replication*: *Note `STOP SLAVE': stop-slave. did not stop connection attempts properly. If the I/O slave thread was attempting to connect, *Note `STOP SLAVE': stop-slave. waited for the attempt to finish, sometimes for a long period of time, rather than stopping the slave immediately. (Bug #31024) See also Bug #30932. * *Replication*: Issuing a *Note `DROP VIEW': drop-view. statement caused replication to fail if the view did not actually exist. (Bug #30998) * *Replication*: Replication of *Note `LOAD DATA INFILE': load-data. could fail when `read_buffer_size' was larger than `max_allowed_packet'. (Bug #30435) * *Replication*: Replication crashed with the *Note `NDB': mysql-cluster. storage engine when *Note `mysqld': mysqld. was started with `--character-set-server=ucs2'. (Bug #29562) * *Replication*: When using row-based logging, nontransactional updates were not written atomically to the binary log. If a nontransactional update was made concurrently with some other update, this could cause incorrect binary logging, and consequently the slave could diverge from the master. Now, nontransactional updates are always written atomically to the binary log. (Bug #29020) * *Replication*: Setting `server_id' did not update its value for the current session. (Bug #28908) * *Replication*: Some older servers wrote events to the binary log using different numbering from what is currently used, even though the file format number in the file is the same. Slaves running MySQL 5.1.18 and later could not read these binary logs properly. Binary logs from these older versions now are recognized and event numbers are mapped to the current numbering so that they can be interpreted properly. (Bug #27779, Bug #32434) This regression was introduced by Bug #22583. * *Replication*: `MASTER_POS_WAIT()' did not return `NULL' when the server was not a slave. (Bug #26622) * *Replication*: The nonspecific error message `Wrong parameters to function register_slave' resulted when *Note `START SLAVE': start-slave. failed to register on the master due to excess length of any the slave server options `--report-host', `--report-user', or `--report-password'. An error message specific to each of these options is now returned in such cases. The new error messages are: * `Failed to register slave: too long 'report-host'' * `Failed to register slave: too long 'report-user'' * `Failed to register slave; too long 'report-password'' (Bug #22989) See also Bug #19328. * *Replication*: `PURGE BINARY LOGS TO' and `PURGE BINARY LOGS BEFORE' did not handle missing binary log files correctly or in the same way. Now for both of these statements, if any files listed in the `.index' file are missing from the file system, the statement fails with an error. (Bug #18199, Bug #18453) * *Replication*: `START SLAVE UNTIL MASTER_LOG_POS=POSITION' issued on a slave that was using `--log-slave-updates' and that was involved in circular replication would cause the slave to run and stop one event later than that specified by the value of POSITION. (Bug #13861) * Manually replacing a binary log file with a directory having the same name caused an error that was not handled correctly. (Bug #35675) * Using *Note `LOAD DATA INFILE': load-data. with a view could crash the server. (Bug #35469) * Selecting from *Note `INFORMATION_SCHEMA.REFERENTIAL_CONSTRAINTS': referential-constraints-table. could cause a server crash. (Bug #35406) See also Bug #35108. * For a `TEMPORARY' table, *Note `DELETE': delete. with no `WHERE' clause could fail when preceded by *Note `DELETE': delete. statements with a `WHERE' clause. (Bug #35392) * If the server crashed with an `InnoDB' error due to unavailability of undo slots, errors could persist during rollback when the server was restarted: There are two `UNDO' slot caches (for *Note `INSERT': insert. and *Note `UPDATE': update.). If all slots end up in one of the slot caches, a request for a slot from the other slot cache would fail. This can happen if the request is for an *Note `UPDATE': update. slot and all slots are in the *Note `INSERT': insert. slot cache, or vice versa. (Bug #35352) * In some cases, when too many clients tried to connect to the server, the proper `SQLSTATE' code was not returned. (Bug #35289) * Memory-allocation failures for attempts to set `key_buffer_size' to large values could result in a server crash. (Bug #35272) * For `InnoDB' tables, `ALTER TABLE DROP' failed if the name of the column to be dropped began with `foreign'. (Bug #35220) * Queries could return different results depending on whether `ORDER BY' columns were indexed. (Bug #35206) * When a view containing a reference to `DUAL' was created, the reference was removed when the definition was stored, causing some queries against the view to fail with invalid SQL syntax errors. (Bug #35193) * `SELECT ... FROM INFORMATION_SCHEMA.REFERENTIAL_CONSTRAINTS' caused the server to crash if the table referenced by a foreign key had been dropped. This issue was observed on Windows platforms only. (Bug #35108) See also Bug #35406. * Debugging symbols were missing for some executables in Windows binary distributions. (Bug #35104) * Nonconnection threads were being counted in the value of the `Max_used_connections' status variable. (Bug #35074) * A query that performed a `ref_or_null' join where the second table used a key having one or columns that could be `NULL' and had a column value that was `NULL' caused the server to crash. (Bug #34945) This regression was introduced by Bug #12144. * For some queries, the optimizer used an ordered index scan for `GROUP BY' or `DISTINCT' when it was supposed to use a loose index scan, leading to incorrect results. (Bug #34928) * Creating a foreign key on an `InnoDB' table that was created with an explicit `AUTO_INCREMENT' value caused that value to be reset to 1. (Bug #34920) * *Note `mysqldump': mysqldump. failed to return an error code when using the `--master-data' option without binary logging being enabled on the server. (Bug #34909) * Under some circumstances, the value of *Note `mysql_insert_id()': mysql-insert-id. following a `SELECT ... INSERT' statement could return an incorrect value. This could happen when the last `SELECT ... INSERT' did not involve an `AUTO_INCREMENT' column, but the value of *Note `mysql_insert_id()': mysql-insert-id. was changed by some previous statements. (Bug #34889) * Table and database names were mixed up in some places of the subquery transformation procedure. This could affect debugging trace output and further extensions of that procedure. (Bug #34830) * If `fsync()' returned `ENOLCK', `InnoDB' could treat this as fatal and cause abnormal server termination. `InnoDB' now retries the operation. (Bug #34823) * *Note `CREATE SERVER': create-server. and *Note `ALTER SERVER': alter-server. could crash the server if out-of-memory conditions occurred. (Bug #34790) * *Note `DROP SERVER': drop-server. does not release memory cached for server structures created by *Note `CREATE SERVER': create-server, so repeated iterations of these statements resulted in a memory leak. *Note `FLUSH PRIVILEGES': flush. now releases the memory allocated for *Note `CREATE SERVER': create-server. (Bug #34789) * A malformed URL used for a `FEDERATED' table's `CONNECTION' option value in a *Note `CREATE TABLE': create-table. statement was not handled correctly and could crash the server. (Bug #34788) * Queries such as `SELECT ROW(1, 2) IN (SELECT t1.a, 2) FROM t1 GROUP BY t1.a' (combining row constructors and subqueries in the `FROM' clause) could lead to assertion failure or unexpected error messages. (Bug #34763) * Using `NAME_CONST()' with a negative number and an aggregate function caused MySQL to crash. This could also have a negative impact on replication. (Bug #34749) * A memory-handling error associated with use of `GROUP_CONCAT()' in subqueries could result in a server crash. (Bug #34747) * For an indexed integer column COL_NAME and a value N that is one greater than the maximum value permitted for the data type of COL_NAME, conditions of the form `WHERE COL_NAME < N' failed to return rows where the value of COL_NAME is `N - 1'. (Bug #34731) * A server running with the `--debug' option could attempt to dereference a null pointer when opening tables, resulting in a crash. (Bug #34726) * Assigning an `incremental' value to the `debug' system variable did not add the new value to the current value. For example, if the current `debug' value was `'T'', the statement `SET debug = '+P'' resulted in a value of `'P'' rather than the correct value of `'P:T''. (Bug #34678) * For debug builds, reading from *Note `INFORMATION_SCHEMA.TABLES': tables-table. or *Note `INFORMATION_SCHEMA.COLUMNS': columns-table. could cause assertion failures. This could happen under rare circumstances when `INFORMATION_SCHEMA' fails to get information about a table (for example, when a connection is killed). (Bug #34656) * Executing a *Note `TRUNCATE TABLE': truncate-table. statement on a table having both a foreign key reference and a *Note `DELETE': delete. trigger crashed the server. (Bug #34643) * Some subqueries using an expression that included an aggregate function could fail or in some cases lead to a crash of the server. (Bug #34620) * Dangerous pointer arithmetic crashed the server on some systems. (Bug #34598) * Creating a view inside a stored procedure could lead to a crash of the MySQL Server. (Bug #34587) * A server crash could occur if `INFORMATION_SCHEMA' tables built in memory were swapped out to disk during query execution. (Bug #34529) * `CAST(AVG(ARG) AS DECIMAL)' produced incorrect results for non-*Note `DECIMAL': numeric-types. arguments. (Bug #34512) * The per-thread debugging settings stack was not being deallocated before thread termination, resulting in a stack memory leak. (Bug #34424) * Executing an *Note `ALTER VIEW': alter-view. statement on a table crashed the server. (Bug #34337) * `InnoDB' could crash if overflow occurred for an `AUTO_INCREMENT' column. (Bug #34335) * For `InnoDB', exporting and importing a table could corrupt *Note `TINYBLOB': blob. columns, and a subsequent *Note `ALTER TABLE': alter-table. could corrupt *Note `TINYTEXT': blob. columns as well. (Bug #34300) * `DEFAULT 0' was not permitted for the *Note `YEAR': year. data type. (Bug #34274) * Under some conditions, a `SET GLOBAL innodb_commit_concurrency' or `SET GLOBAL innodb_autoextend_increment' statement could fail. (Bug #34223) * *Note `mysqldump': mysqldump. attempts to set the `character_set_results' system variable after connecting to the server. This failed for pre-4.1 servers that have no such variable, but *Note `mysqldump': mysqldump. did not account for this and 1) failed to dump database contents; 2) failed to produce any error message alerting the user to the problem. (Bug #34192) * Use of stored functions in the `WHERE' clause for *Note `SHOW OPEN TABLES': show-open-tables. caused a server crash. (Bug #34166) * For a `FEDERATED' table with an index on a nullable column, accessing the table could crash a server, return an incorrect result set, or return `ERROR 1030 (HY000): Got error 1430 from storage engine'. (Bug #33946) * Passing anything other than an integer argument to a `LIMIT' clause in a prepared statement would fail. (This limitation was introduced to avoid replication problems; for example, replicating the statement with a string argument would cause a parse failure in the slave). Now, arguments to the `LIMIT' clause are converted to integer values, and these converted values are used when logging the statement. (Bug #33851) * An internal buffer in *Note `mysql': mysql. was too short. Overextending it could cause stack problems or segmentation violations on some architectures. (This is not a problem that could be exploited to run arbitrary code.) (Bug #33841) * A query using `WHERE (column1='STRING1' AND column2=CONSTANT1) OR (column1='STRING2' AND column2=CONSTANT2)', where `col1' used a binary collation and STRING1 matched STRING2 except for case, failed to match any records even when matches were found by a query using the equivalent clause `WHERE column2=CONSTANT1 OR column2=CONSTANT2'. (Bug #33833) * Large unsigned integers were improperly handled for prepared statements, resulting in truncation or conversion to negative numbers. (Bug #33798) * Reuse of prepared statements could cause a memory leak in the embedded server. (Bug #33796) * The server crashed when executing a query that had a subquery containing an equality X=Y where Y referred to a named select list expression from the parent select. The server crashed when trying to use the X=Y equality for `ref'-based access. (Bug #33794) * Some queries using a combination of `IN', `CONCAT()', and an implicit type conversion could return an incorrect result. (Bug #33764) * In some cases a query that produced a result set when using `ORDER BY ASC' did not return any results when this was changed to `ORDER BY DESC'. (Bug #33758) * Disabling concurrent inserts caused some cacheable queries not to be saved in the query cache. (Bug #33756) * `ORDER BY ... DESC' sorts could produce misordered results. (Bug #33697) * The server could crash when *Note `REPEAT': repeat-statement. or another control instruction was used in conjunction with labels and a *Note `LEAVE': leave-statement. instruction. (Bug #33618) * The parser permitted control structures in compound statements to have mismatched beginning and ending labels. (Bug #33618) * `make_binary_distribution' passed the `--print-libgcc-file' option to the C compiler, but this does not work with the `ICC' compiler. (Bug #33536) * Threads created by the event scheduler were incorrectly counted against the `max_connections' thread limit, which could lead to client lockout. (Bug #33507) * Dropping a function after dropping the function's creator could cause the server to crash. (Bug #33464) * Certain combinations of views, subselects with outer references and stored routines or triggers could cause the server to crash. (Bug #33389) * `SET GLOBAL myisam_max_sort_file_size=DEFAULT' set `myisam_max_sort_file_size' to an incorrect value. (Bug #33382) See also Bug #31177. * *Note `ENUM': enum.- or `SET'-valued plugin variables could not be set from the command line. (Bug #33358) * Loading plugins using command-line options to *Note `mysqld': mysqld. could cause an assertion failure. (Bug #33345) * `SLEEP(0)' failed to return on 64-bit Mac OS X due to a bug in `pthread_cond_timedwait()'. (Bug #33304) * Using `Control+R' in the *Note `mysql': mysql. client caused it to crash. (Bug #33288) * For `MyISAM' tables, *Note `CHECK TABLE': check-table. (non-`QUICK') and any form of *Note `REPAIR TABLE': repair-table. incorrected treated rows as corrupted under the combination of the following conditions: * The table had dynamic row format * The table had a *Note `CHAR': char. (not *Note `VARCHAR': char.) column longer than 127 bytes (for multi-byte character sets this could be less than 127 characters) * The table had rows with a signifcant length of more than 127 bytes significant length in that *Note `CHAR': char. column (that is, a byte beyond byte position 127 must be a nonspace character) This problem affected *Note `CHECK TABLE': check-table, *Note `REPAIR TABLE': repair-table, *Note `OPTIMIZE TABLE': optimize-table, *Note `ALTER TABLE': alter-table. *Note `CHECK TABLE': check-table. reported and marked the table as crashed if any row was present that fulfilled the third condition. The other statements deleted these rows. (Bug #33222) * Granting the `UPDATE' privilege on one column of a view caused the server to crash. (Bug #33201) * For *Note `DECIMAL': numeric-types. columns used with the `ROUND(X,D)' or `TRUNCATE(X,D)' function with a nonconstant value of D, adding an `ORDER BY' for the function result produced misordered output. (Bug #33143) See also Bug #33402, Bug #30617. * The `CSV' engine did not honor update requests for *Note `BLOB': blob. columns when the new column value had the same length as the value to be updated. (Bug #33067) * After receiving a `SIGHUP' signal, the server could crash, and user-specified log options were ignored when reopening the logs. (Bug #33065) * When MySQL was built with OpenSSL, the SSL library was not properly initialized with information of which endpoint it was (server or client), causing connection failures. (Bug #33050) * Under some circumstances a combination of aggregate functions and `GROUP BY' in a *Note `SELECT': select. query over a view could lead to incorrect calculation of the result type of the aggregate function. This in turn could lead to incorrect results, or to crashes on debug builds of the server. (Bug #33049) * For `DISTINCT' queries, MySQL 4.0 and 4.1 stopped reading joined tables as soon as the first matching row was found. However, this optimization was lost in MySQL 5.0, which instead read all matching rows. This fix for this regression may result in a major improvement in performance for `DISTINCT' queries in cases where many rows match. (Bug #32942) * Repeated creation and deletion of views within prepared statements could eventually crash the server. (Bug #32890) See also Bug #34587. * Incorrect assertions could cause a server crash for *Note `DELETE': delete. triggers for transactional tables. (Bug #32790) * In some cases where setting a system variable failed, no error was sent to the client, causing the client to hang. (Bug #32757) * Enabling the `PAD_CHAR_TO_FULL_LENGTH' SQL mode caused privilege-loading operations (such as *Note `FLUSH PRIVILEGES': flush.) to include trailing spaces from grant table values stored in *Note `CHAR': char. columns. Authentication for incoming connections failed as a result. Now privilege loading does not include trailing spaces, regardless of SQL mode. (Bug #32753) * The *Note `SHOW ENGINE INNODB STATUS': show-engine. and *Note `SHOW ENGINE INNODB MUTEX': show-engine. statements incorrectly required the `SUPER' privilege rather than the `PROCESS' privilege. (Bug #32710) * Inserting strings with a common prefix into a table that used the `ucs2' character set corrupted the table. (Bug #32705) * Tables in the `mysql' database that stored the current `sql_mode' value as part of stored program definitions were not updated with newer mode values (`NO_ENGINE_SUBSTITUTION', `PAD_CHAR_TO_FULL_LENGTH'). This causes various problems defining stored programs if those modes were included in the current `sql_mode' value. (Bug #32633) * A view created with a string literal for one of the columns picked up the connection character set, but not the collation. Comparison to that field therefore used the default collation for that character set, causing an error if the connection collation was not compatible with the default collation. The problem was caused by text literals in a view being dumped with a character set introducer even when this was not necessary, sometimes leading to a loss of collation information. Now the character set introducer is dumped only if it was included in the original query. (Bug #32538) See also Bug #21505. * Queries using `LIKE' on tables having indexed *Note `CHAR': char. columns using either of the `eucjpms' or `ujis' character sets did not return correct results. (Bug #32510) * Executing a prepared statement associated with a materialized cursor sent to the client a metadata packet with incorrect table and database names. The problem occurred because the server sent the name of the temporary table used by the cursor instead of the table name of the original table. The same problem occurred when selecting from a view, in which case the name of the table name was sent, rather than the name of the view. (Bug #32265) * On Windows, `mysqltest_embedded.exe' did not properly execute the `send' command. (Bug #32044) * A variable named `read_only' could be declared even though that is a reserved word. (Bug #31947) * On Windows, the build process failed with four parallel build threads. (Bug #31929) * Queries testing numeric constants containing leading zeros against `ZEROFILL' columns were not evaluated correctly. (Bug #31887) * If an error occurred during file creation, the server sometimes did not remove the file, resulting in an unused file in the file system. (Bug #31781) * The *Note `mysqld': mysqld. crash handler failed on Windows. (Bug #31745) * When upgrading from MySQL 5.1.19 to any version between MySQL 5.1.20 to MySQL 5.1.23, the MySQL Instance Configuration Wizard would fail to account for the change in name for the *Note `mysqld-nt.exe': mysqld. to *Note `mysqld.exe': mysqld, causing MySQL to fail to start properly after the upgrade. (Bug #31674) * The server returned the error message `Out of memory; restart server and try again' when the actual problem was that the sort buffer was too small. Now an appropriate error message is returned in such cases. (Bug #31590) * A table having an index that included a *Note `BLOB': blob. or *Note `TEXT': blob. column, and that was originally created with a MySQL server using version 4.1 or earlier, could not be opened by a 5.1 or later server. (Bug #31331) * The *Note `mysql_change_user()': mysql-change-user. C API function caused global `Com_XXX' status variable values to be incorrect. (Bug #31222) * When sorting privilege table rows, the server treated escaped wildcard characters (`\%' and `\_') the same as unescaped wildcard characters (`%' and `_'), resulting in incorrect row ordering. (Bug #31194) * On Windows, *Note `SHOW PROCESSLIST': show-processlist. could display process entries with a `State' value of `*** DEAD ***'. (Bug #30960) * `ROUND(X,D)' or `TRUNCATE(X,D)' for nonconstant values of D could crash the server if these functions were used in an `ORDER BY' that was resolved using `filesort'. (Bug #30889) * Resetting the query cache by issuing a `SET GLOBAL query_cache_size=0' statement caused the server to crash if it concurrently was saving a new result set to the query cache. (Bug #30887) * Manifest problems prevented `MySQLInstanceConfig.exe' from running on Windows Vista. (Bug #30823) * If an alias was used to refer to the value returned by a stored function within a subselect, the outer select recognized the alias but failed to retrieve the value assigned to it in the subselect. (Bug #30787) * Binary logging for a stored procedure differed depending on whether or not execution occurred in a prepared statement. (Bug #30604) * An orphaned PID file from a no-longer-running process could cause *Note `mysql.server': mysql-server. to wait for that process to exit even though it does not exist. (Bug #30378) * The `Table_locks_waited' waited variable was not incremented in the cases that a lock had to be waited for but the waiting thread was killed or the request was aborted. (Bug #30331) * The `Com_create_function' status variable was not incremented properly. (Bug #30252) * View metadata returned from *Note `INFORMATION_SCHEMA.VIEWS': views-table. was changed by the fix for Bug#11986, causing the information returned in MySQL 5.1 to differ from that returned in 5.0. (Bug #30217) * *Note `mysqld': mysqld. displayed the `--enable-pstack' option in its help message even if MySQL was configured without `--with-pstack'. (Bug #29836) * The *Note `mysql_config': mysql-config. command would output `CFLAGS' values that were incompatible with C++ for the HP-UX platform. (Bug #29645) * Views were treated as insertable even if some base table columns with no default value were omitted from the view definition. (This is contrary to the condition for insertability that a view must contain all columns in the base table that do not have a default value.) (Bug #29477) * *Note `myisamchk': myisamchk. always reported the character set for a table as `latin1_swedish_ci (8)' regardless of the table' actual character set. (Bug #29182) * `InnoDB' could return an incorrect rows-updated value for *Note `UPDATE': update. statements. (Bug #29157) * The MySQL preferences pane did not work to start or stop MySQL on Mac OS X 10.5 (Leopard). (Bug #28854) * For upgrading to a new major version using RPM packages (such as 4.1 to 5.0), if the installation procedure found an existing MySQL server running, it could fail to shut down the old server, but also erroneously removed the server's socket file. Now the procedure checks for an existing server package from a different vendor or major MySQL version. In such case, it refuses to install the server and recommends how to safely remove the old packages before installing the new ones. (Bug #28555) * *Note `mysqlhotcopy': mysqlhotcopy. silently skipped databases with names consisting of two alphanumeric characters. (Bug #28460) * No information was written to the general query log for the `COM_STMT_CLOSE', `COM_STMT_RESET', and `COM_STMT_SEND_LONG_DATA' commands. (These occur when a client invokes the *Note `mysql_stmt_close()': mysql-stmt-close, *Note `mysql_stmt_reset()': mysql-stmt-reset. and *Note `mysql_stmt_send_long_data()': mysql-stmt-send-long-data. C API functions.) (Bug #28386) * Previously, the parser accepted the ODBC `{ OJ ... LEFT OUTER JOIN ...}' syntax for writing left outer joins. The parser now permits `{ OJ ... }' to be used to write other types of joins, such as `INNER JOIN' or `RIGHT OUTER JOIN'. This helps with compatibility with some third-party applications, but is not official ODBC syntax. (Bug #28317) * The `FEDERATED' storage engine did not perform identifier quoting for column names that are reserved words when sending statements to the remote server. (Bug #28269) * The SQL parser did not accept an empty `UNION=()' clause. This meant that, when there were no underlying tables specified for a *Note `MERGE': merge-storage-engine. table, *Note `SHOW CREATE TABLE': show-create-table. and *Note `mysqldump': mysqldump. both output statements that could not be executed. Now it is possible to execute a *Note `CREATE TABLE': create-table. or *Note `ALTER TABLE': alter-table. statement with an empty `UNION=()' clause. However, *Note `SHOW CREATE TABLE': show-create-table. and *Note `mysqldump': mysqldump. do not output the `UNION=()' clause if there are no underlying tables specified for a *Note `MERGE': merge-storage-engine. table. This also means it is now possible to remove the underlying tables for a *Note `MERGE': merge-storage-engine. table using *Note `ALTER TABLE ... UNION=()': alter-table. (Bug #28248) * It was possible to exhaust memory by repeatedly running `index_merge' queries and never performing any *Note `FLUSH TABLES': flush. statements. (Bug #27732) * When `utf8' was set as the connection character set, using `SPACE()' with a non-Unicode column produced an error. (Bug #27580) See also Bug #23637. * The parser rules for the *Note `SHOW PROFILE': show-profile. statement were revised to work with older versions of `bison'. (Bug #27433) * *Note `resolveip': resolveip. failed to produce correct results for host names that begin with a digit. (Bug #27427) * In `ORDER BY' clauses, mixing aggregate functions and nongrouping columns is not permitted if the `ONLY_FULL_GROUP_BY' SQL mode is enabled. However, in some cases, no error was thrown because of insufficient checking. (Bug #27219) * For the `--record_log_pos' option, *Note `mysqlhotcopy': mysqlhotcopy. now determines the slave status information from the result of *Note `SHOW SLAVE STATUS': show-slave-status. by using the `Relay_Master_Log_File' and `Exec_Master_Log_Pos' values rather than the `Master_Log_File' and `Read_Master_Log_Pos' values. This provides a more accurate indication of slave execution relative to the master. (Bug #27101) * The MySQL Instance Configuration Wizard would not permit you to choose a service name, even though the criteria for the service name were valid. The code that checks the name has been updated to support the correct criteria of any string less than 256 character and not containing either a forward or backward slash character. (Bug #27013) * Memory corruption, a crash of the MySQL server, or both, could take place if a low-level I/O error occurred while an `ARCHIVE' table was being opened. (Bug #26978) * *Note `DROP DATABASE': drop-database. failed for attempts to drop databases with names that contained the legacy `#mysql50#' name prefix. (Bug #26703) * `config-win.h' unconditionally defined `bool' as *Note `BOOL': numeric-types, causing problems on systems where `bool' is 1 byte and *Note `BOOL': numeric-types. is 4 bytes. (Bug #26461) * On Windows, for distributions built with debugging support, *Note `mysql': mysql. could crash if the user typed `Control+C'. (Bug #26243) * The XPath `boolean()' function did not cast string and nodeset values correctly in some cases. It now returns `TRUE' for any nonempty string or nodeset and 0 for a `NULL' string, as specified in the XPath standard.. (Bug #26051) * When symbolic links were disabled, either with a server startup option or by enabling the `NO_DIR_IN_CREATE' SQL mode, *Note `CREATE TABLE': create-table. silently ignored the `DATA DIRECTORY' and `INDEX DIRECTORY' table options. Now the server issues a warning if symbolic links are disabled when these table options are used. (Bug #25677) * Attempting to create an index with a prefix on a *Note `DECIMAL': numeric-types. column appeared to succeed with an inaccurate warning message. Now, this action fails with the error `Incorrect prefix key; the used key part isn't a string, the used length is longer than the key part, or the storage engine doesn't support unique prefix keys'. (Bug #25426) * *Note `mysqlcheck -A -r': mysqlcheck. did not correctly identify all tables that needed repairing. (Bug #25347) * On Windows, an error in `configure.js' caused installation of source distributions to fail. (Bug #25340) * The `Qcache_free_blocks' status variable did not display a value of 0 if the query cache was disabled. (Bug #25132) * The client library had no way to return an error if no connection had been established. This caused problems such as *Note `mysql_library_init()': mysql-library-init. failing silently if no `errmsg.sys' file was available. (Bug #25097) * On Mac OS X, the StartupItem for MySQL did not work. (Bug #25008) * For Windows 64-bit builds, enabling shared-memory support caused client connections to fail. (Bug #24992) * *Note `mysql': mysql. did not use its completion table. Also, the table contained few entries. (Bug #24624) * If a user installed MySQL Server and set a password for the `root' user, and then uninstalled and reinstalled MySQL Server to the same location, the user could not use the MySQL Instance Config wizard to configure the server because the uninstall operation left the previous data directory intact. The config wizard _assumed_ that any new install (not an upgrade) would have the default data directory where the `root' user has no password. The installer now writes a registry key named `FoundExistingDataDir'. If the installer finds an existing data directory, the key will have a value of 1, otherwise it will have a value of 0. When `MySQLInstanceConfig.exe' is run, it will attempt to read the key. If it can read the key, and the value is 1 and there is no existing instance of the server (indicating a new installation), the Config Wizard will permit the user to input the old password so the server can be configured. (Bug #24215) * Logging of statements to log tables was incorrect for statements that contained `utf8'-incompatible binary strings. Incompatible sequences are hex-encoded now. (Bug #23924) * The MySQL header files contained some duplicate macro definitions that could cause compilation problems. (Bug #23839) * *Note `SHOW COLUMNS': show-columns. on a `TEMPORARY' table caused locking issues. (Bug #23588) * For distributions compiled with the bundled `libedit' library, there were difficulties using the *Note `mysql': mysql. client to enter input for non-ASCII or multi-byte characters. (Bug #23097) * *Note `perror': perror. reported incomplete or inaccurate information. (Bug #23028, Bug #25177) * After stopping and starting the event scheduler, disabled events could remain in the execution queue. (Bug #22738) * The server produced a confusing error message when attempting to open a table that required a storage engine that was not loaded. (Bug #22708) * For views or stored programs created with an invalid `DEFINER' value, the error message was confusing (did not tie the problem to the `DEFINER' clause) and has been improved. (Bug #21854) * Warnings for deprecated syntax constructs used in stored routines make sense to report only when the routine is being created, but they were also being reported when the routine was parsed for loading into the execution cache. Now they are reported only at routine creation time. (Bug #21801) * On Mac OS X, *Note `mysqld': mysqld. did not react to Control+C when run under `gdb', even when run with the `--gdb' option. (Bug #21567) * `CREATE ... SELECT' did not always set `DEFAULT' column values in the new table. (Bug #21380) * *Note `mysql_config': mysql-config. output did not include `-lmygcc' on some platforms when it was needed. (Bug #21158) * `mysql-stress-test.pl' and `mysqld_multi.server.sh' were missing from some binary distributions. (Bug #21023, Bug #25486) * The `BENCHMARK()' function, invoked with more than 2147483648 iterations (the size of a signed 32-bit integer), terminated prematurely. (Bug #20752) * *Note `mysqldumpslow': mysqldumpslow. returned a confusing error message when no configuration file was found. (Bug #20455) * `MySQLInstanceConfig.exe' could lose the `innodb_data_home_dir' setting when reconfiguring an instance. (Bug #19797) * *Note `DROP DATABASE': drop-database. did not drop orphaned `FOREIGN KEY' constraints. (Bug #18942) * *Note `CREATE TABLE': create-table. permitted 0 as the default value for a *Note `TIMESTAMP': datetime. column when the server was running in `NO_ZERO_DATE' mode. (Bug #18834) * A `SET' column whose definition specified 64 elements could not be updated using integer values. (Bug #15409) * If a *Note `SELECT': select. calls a stored function in a transaction, and a statement within the function fails, that statement should roll back. Furthermore, if *Note `ROLLBACK': commit. is executed after that, the entire transaction should be rolled back. Before this fix, the failed statement did not roll back when it failed (even though it might ultimately get rolled back by a *Note `ROLLBACK': commit. later that rolls back the entire transaction). (Bug #12713) See also Bug #34655. * The parser incorrectly permitted `SQLSTATE '00000'' to be specified for a condition handler. (This is incorrect because the condition must be a failure condition and `'00000'' indicates success.) (Bug #8759) * `MySQLInstanceConfig.exe' did not save the `innodb_data_home_dir' value to the `my.ini' file under certain circumstances. (Bug #6627)  File: manual.info, Node: news-5-1-23, Next: news-5-1-22, Prev: news-5-1-24, Up: news-5-1-x D.1.45 Changes in MySQL 5.1.23 (29 January 2008) ------------------------------------------------ *Functionality added or changed:* * *Important Change*: *Partitioning*: *Security Fix*: It was possible, by creating a partitioned table using the `DATA DIRECTORY' and `INDEX DIRECTORY' options to gain privileges on other tables having the same name as the partitioned table. As a result of this fix, any table-level `DATA DIRECTORY' or `INDEX DIRECTORY' options are now ignored for partitioned tables. (Bug #32091, CVE-2007-5970) See also Bug #29325, Bug #32111. * *Incompatible Change*: In MySQL 5.1.6, when log tables were implemented, the default log destination for the general query and slow query log was `TABLE'. This default has been changed to `FILE', which is compatible with MySQL 5.0, but incompatible with earlier releases of MySQL 5.1 from 5.1.6 to 5.1.20. If you are upgrading from MySQL 5.0 to 5.1.21 or higher, no logging option changes should be necessary. However, if you are upgrading from 5.1.6 through 5.1.20 to 5.1.21 or higher and were using `TABLE' logging, use the `--log-output=TABLE' option explicitly to preserve your server's table-logging behavior. The MySQL 5.1.23 fix is in addition to a fix in 5.1.21 because it turned out that the default was set in two places, only one of which was fixed the first time. (Bug #29993) * *Incompatible Change* The parser accepted statements that contained `/* ... */' that were not properly closed with `*/', such as `SELECT 1 /* + 2'. Statements that contain unclosed `/*'-comments now are rejected with a syntax error. This fix has the potential to cause incompatibilities. Because of Bug#26302, which caused the trailing `*/' to be truncated from comments in views, stored routines, triggers, and events, it is possible that objects of those types may have been stored with definitions that now will be rejected as syntactically invalid. Such objects should be dropped and re-created so that their definitions do not contain truncated comments. (Bug #28779) * *MySQL Cluster*: The following improvements have been made in the *Note `ndb_size.pl': mysql-cluster-programs-ndb-size-pl. utility: * The script can now be used with multiple databases; lists of databases and tables can also be excluded from analysis. * Schema name information has been added to index table calculations. * The database name is now an optional parameter, the exclusion of which causes all databases to be examined. * If selecting from `INFORMATION_SCHEMA' fails, the script now attempts to fall back to *Note `SHOW TABLES': show-tables. * A `--real_table_name' option has been added; this designates a table to handle unique index size calculations. * The report title has been amended to cover cases where more than one database is being analyzed. Support for a `--socket' option was also added. For more information, see *Note mysql-cluster-programs-ndb-size-pl::. (Bug #28683, Bug #28253) * *MySQL Cluster*: Mapping of *Note `NDB': mysql-cluster. error codes to MySQL storage engine error codes has been improved. (Bug #28423) * *MySQL Cluster*: The output of the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client `SHOW' and `STATUS' commands now indicates when the cluster is in single user mode. (Bug #27999) * *MySQL Cluster*: The output from the cluster management client showing the progress of data node starts has been improved. (Bug #23354) * *Partitioning*: Error messages for partitioning syntax errors have been made more descriptive. (Bug #29368) * *Replication*: Replication of the following SQL functions now switches to row-based logging in `MIXED' mode, and generates a warning in `STATEMENT' mode: * `USER()' * `CURRENT_USER()' and its alias `CURRENT_USER' * `FOUND_ROWS()' * `ROW_COUNT()' See *Note binary-log-mixed::, for more information. (Bug #12092, Bug #28086, Bug #30244) * *Note `mysqldump': mysqldump. information at the top of the output now shows the same information as *Note `mysqldump': mysqldump. invoked with the `-V' option, namely the *Note `mysqldump': mysqldump. version number, the MySQL server version, and the distribution. (Bug #32350) * `mysqltest' now has a `change_user' command to change the user for the current connection. (It invokes the *Note `mysql_change_user()': mysql-change-user. C API function.) (Bug #31608) * `mysql-test-run.pl' now permits a suite name prefix to be specified in command-line arguments that name test cases. The test name syntax now is `[SUITE_NAME.]TEST_NAME[.SUFFIX]'. For example, `mysql-test-run.pl binlog.mytest' runs the `mytest.test' test in the `binlog' test suite. (Bug #31400) * The `--event-scheduler' option without a value disabled the event scheduler. Now it enables the event scheduler. (Bug #31332) * *Note `mysqldump': mysqldump. produces a `-- Dump completed on DATE' comment at the end of the dump if `--comments' is given. The date causes dump files for identical data take at different times to appear to be different. The new options `--dump-date' and `--skip-dump-date' control whether the date is added to the comment. `--skip-dump-date' suppresses date printing. The default is `--dump-date' (include the date in the comment). (Bug #31077) * Server parser performance was improved for expression parsing by lowering the number of state transitions and reductions needed. (Bug #30625) * Server parser performance was improved for identifier lists, expression lists, and UDF expression lists. (Bug #30333) * Server parser performance was improved for boolean expressions. (Bug #30237) * The `LAST_EXECUTED' column of the *Note `INFORMATION_SCHEMA.EVENTS': events-table. table now indicates when the event started executing rather than when it finished executing. As a result, the `ENDS' column is never less than `LAST_EXECUTED'. (Bug #29830) * The `mysql_odbc_escape_string()' C API function has been removed. It has multi-byte character escaping issues, doesn't honor the `NO_BACKSLASH_ESCAPES' SQL mode and is not needed anymore by Connector/ODBC as of 3.51.17. (Bug #29592) See also Bug #41728. * If a `MyISAM' table is created with no `DATA DIRECTORY' option, the `.MYD' file is created in the database directory. By default, if `MyISAM' finds an existing `.MYD' file in this case, it overwrites it. The same applies to `.MYI' files for tables created with no `INDEX DIRECTORY' option. To suppress this behavior, start the server with the new `--keep_files_on_create' option, in which case `MyISAM' will not overwrite existing files and returns an error instead. (Bug #29325) * The default value of the `connect_timeout' system variable was increased from 5 to 10 seconds. This might help in cases where clients frequently encounter errors of the form `Lost connection to MySQL server at 'XXX', system error: ERRNO'. (Bug #28359) * MySQL now can be compiled with `gcc' 4.2.x. There was a problem involving a conflict with the `min()' and `max()' macros in `my_global.h'. (Bug #28184) * `mysql-test-run.pl' now supports a `--combination' option for specifying options to the *Note `mysqld': mysqld. server. This option is similar to `--mysqld' but should be given two or more times. `mysql-test-run.pl' executes multiple test runs, using the options for each instance of `--combination' in successive runs. For test runs specific to a given test suite, an alternative to the use of `--combination' is to create a `combinations' file in the suite directory. The file should contain a section of options for each test run. * The argument for the `mysql-test-run.pl' `--do-test' and `--skip-test' options is now interpreted as a Perl regular expression if there is a pattern metacharacter in the argument value. This enables more flexible specification of which tests to perform or skip. *Bugs fixed:* * *Performance*: If a `LIMIT' clause was present, the server could fail to consider indexes that could be used for `ORDER BY' or `GROUP BY'. (Bug #28404) * *Security Fix*: *Replication*: It was possible for any connected user to issue a *Note `BINLOG': binlog. statement, which could be used to escalate privileges. Use of the *Note `BINLOG': binlog. statement now requires the `SUPER' privilege. (Bug #31611, CVE-2007-6313) * *Security Fix*: Three vulnerabilities in yaSSL versions 1.7.5 and earlier were discovered that could lead to a server crash or execution of unauthorized code. The exploit requires a server with yaSSL enabled and TCP/IP connections enabled, but does not require valid MySQL account credentials. The exploit does not apply to OpenSSL. *Warning*: The proof-of-concept exploit is freely available on the Internet. Everyone with a vulnerable MySQL configuration is advised to upgrade _immediately_. (Bug #33814, CVE-2008-0226, CVE-2008-0227) * *Security Fix*: Using *Note `RENAME TABLE': rename-table. against a table with explicit `DATA DIRECTORY' and `INDEX DIRECTORY' options can be used to overwrite system table information by replacing the symbolic link points. the file to which the symlink points. MySQL will now return an error when the file to which the symlink points already exists. (Bug #32111, CVE-2007-5969) * *Security Fix*: *Note `ALTER VIEW': alter-view. retained the original `DEFINER' value, even when altered by another user, which could enable that user to gain the access rights of the view. Now *Note `ALTER VIEW': alter-view. is permitted only to the original definer or users with the `SUPER' privilege. (Bug #29908) * *Security Fix*: When using a `FEDERATED' table, the local server could be forced to crash if the remote server returned a result with fewer columns than expected. (Bug #29801) * *Security Enhancement*: It was possible to force an error message of excessive length which could lead to a buffer overflow. This has been made no longer possible as a security precaution. (Bug #32707) * *Incompatible Change*: It is no longer possible to create `CSV' tables with `NULL' columns. However, for backward compatibility, you can continue to use such tables that were created in previous MySQL releases. (Bug #32050) * *Incompatible Change*: With `ONLY_FULL_GROUP_BY' SQL mode enabled, queries such as `SELECT a FROM t1 HAVING COUNT(*)>2' were not being rejected as they should have been. This fix results in the following behavior: * There is a check against mixing group and nongroup columns _only_ when `ONLY_FULL_GROUP_BY' is enabled. * This check is done both for the select list and for the `HAVING' clause if there is one. This behavior differs from previous versions as follows: * Previously, the `HAVING' clause was not checked when `ONLY_FULL_GROUP_BY' was enabled; now it is checked. * Previously, the select list was checked even when `ONLY_FULL_GROUP_BY' was not enabled; now it is checked only when `ONLY_FULL_GROUP_BY' is enabled. (Bug #31794) * *Incompatible Change*: Inserting a row with a `NULL' value for a *Note `DATETIME': datetime. column results in a `CSV' file that the storage engine cannot read. All `CSV' tables now need to be defined with each column marked as `NOT NULL'. An error is raised if you try to create a `CSV' table with columns that are not defined with `NOT NULL'. (Bug #31473, Bug #32817) * *Incompatible Change*: *Note `SET PASSWORD': set-password. statements now cause an implicit commit, and thus are prohibited within stored functions and triggers. (Bug #30904) * *Incompatible Change*: The `mysql_install_db' script could fail to locate some components (including *Note `resolveip': resolveip.) during execution if the `--basedir' option was specified on the command-line or within the `my.cnf' file. This was due to a conflict when comparing the compiled-in values and the supplied values. The `--source-install' command-line option to the script has been removed and replaced with the `--srcdir' option. *Note `mysql_install_db': mysql-install-db. now locates components either using the compiled-in options, the `--basedir' option or `--srcdir' option. (Bug #30759) * *Incompatible Change*: Multiple-table *Note `DELETE': delete. statements containing ambiguous aliases could have unintended side effects such as deleting rows from the wrong table. Examples: DELETE FROM t1 AS a2 USING t1 AS a1 INNER JOIN t2 AS a2; DELETE t1 AS a2 FROM t1 AS a1 INNER JOIN t2 AS a2; To avoid ambiguity, declaration of aliases other than in the TABLE_REFERENCES part of the statement should be avoided: DELETE FROM t1 USING t1 AS a1 INNER JOIN t2 AS a2; DELETE t1 FROM t1 AS a1 INNER JOIN t2 AS a2; For the `USING' variant of multiple-table *Note `DELETE': delete. syntax, alias declarations outside the TABLE_REFERENCES part of the statement now are disallowed. (In MySQL 5.5, alias declarations outside TABLE_REFERENCES are disallowed for all multiple-table *Note `DELETE': delete. statements.) Statements containing aliases that are no longer permitted must be rewritten. (Bug #30234) See also Bug #27525. * *Incompatible Change*: Within a stored routine, it is no longer permissible to declare a cursor for a *Note `SHOW': show. or *Note `DESCRIBE': describe. statement. This happened to work in some instances, but is no longer supported. In many cases, a workaround for this change is to use the cursor with a *Note `SELECT': select. query to read from an `INFORMATION_SCHEMA' table that produces the same information as the *Note `SHOW': show. statement. (Bug #29223) * *Incompatible Change*: It was possible to create a view having a column whose name consisted of an empty string or space characters only. One result of this bug fix is that aliases for columns in the view `SELECT' statement are checked to ensure that they are legal column names. In particular, the length must be within the maximum column length of 64 characters, not the maximum alias length of 256 characters. This can cause problems for replication or loading dump files. For additional information and workarounds, see *Note view-restrictions::. (Bug #27695) See also Bug #31202. * *Incompatible Change*: Several type-preserving functions and operators returned an incorrect result type that does not match their argument types: `COALESCE()', `IF()', `IFNULL()', `LEAST()', `GREATEST()', `CASE'. These now aggregate using the precise SQL types of their arguments rather than the internal type. In addition, the result type of the `STR_TO_DATE()' function is now *Note `DATETIME': datetime. by default. (Bug #27216) * *Incompatible Change*: *Note `GRANT': grant. and *Note `REVOKE': revoke. statements now cause an implicit commit, and thus are prohibited within stored functions and triggers. (Bug #21975, Bug #21422, Bug #17244) * *Incompatible Change*: It was possible for option files to be read twice at program startup, if some of the standard option file locations turned out to be the same directory. Now duplicates are removed from the list of files to be read. Also, users could not override system-wide settings using `~/.my.cnf' because `SYSCONFDIR/my.cnf' was read last. The latter file now is read earlier so that `~/.my.cnf' can override system-wide settings. The fix for this problem had a side effect such that on Unix, MySQL programs looked for options in `~/my.cnf' rather than the standard location of `~/.my.cnf'. That problem was addressed as Bug#38180. (Bug #20748) * *Incompatible Change*: A number of problems existed in the implementation of *Note `MERGE': merge-storage-engine. tables that could cause problems. The problems are summarized below: * Bug#26379 - Combination of *Note `FLUSH TABLE': flush. and *Note `REPAIR TABLE': repair-table. corrupts a *Note `MERGE': merge-storage-engine. table. This was caused in a number of situations: 1. A thread trying to lock a *Note `MERGE': merge-storage-engine. table performs busy waiting while *Note `REPAIR TABLE': repair-table. or a similar table administration task is ongoing on one or more of its `MyISAM' tables. 2. A thread trying to lock a *Note `MERGE': merge-storage-engine. table performs busy waiting until all threads that did *Note `REPAIR TABLE': repair-table. or similar table administration tasks on one or more of its `MyISAM' tables in *Note `LOCK TABLES': lock-tables. segments do *Note `UNLOCK TABLES': lock-tables. The difference against problem #1 is that the busy waiting takes place after the administration task. It is terminated by *Note `UNLOCK TABLES': lock-tables. only. 3. Two *Note `FLUSH TABLES': flush. within a *Note `LOCK TABLES': lock-tables. segment can invalidate the lock. This does not require a *Note `MERGE': merge-storage-engine. table. The first *Note `FLUSH TABLES': flush. can be replaced by any statement that requires other threads to reopen the table. In 5.0 and 5.1 a single *Note `FLUSH TABLES': flush. can provoke the problem. * Bug#26867 - Simultaneously executing *Note `LOCK TABLES': lock-tables. and *Note `REPAIR TABLE': repair-table. on a *Note `MERGE': merge-storage-engine. table would result in memory/cpu hogging. Trying DML on a *Note `MERGE': merge-storage-engine. table, which has a child locked and repaired by another thread, made an infinite loop in the server. * Bug#26377 - Deadlock with *Note `MERGE': merge-storage-engine. and *Note `FLUSH TABLE': flush. Locking a *Note `MERGE': merge-storage-engine. table and its children in parent-child order and flushing the child deadlocked the server. * Bug#25038 - Waiting *Note `TRUNCATE TABLE': truncate-table. Truncating a *Note `MERGE': merge-storage-engine. child, while the *Note `MERGE': merge-storage-engine. table was in use, let the truncate fail instead of waiting for the table to become free. * Bug#25700 - *Note `MERGE': merge-storage-engine. base tables get corrupted by *Note `OPTIMIZE TABLE': optimize-table, *Note `ANALYZE TABLE': analyze-table, or *Note `REPAIR TABLE': repair-table. Repairing a child of an open *Note `MERGE': merge-storage-engine. table corrupted the child. It was necessary to *Note `FLUSH': flush. the child first. * Bug#30275 - *Note `MERGE': merge-storage-engine. tables: *Note `FLUSH TABLES': flush. or *Note `UNLOCK TABLES': lock-tables. causes server to crash. Flushing and optimizing locked *Note `MERGE': merge-storage-engine. children crashed the server. * Bug#19627 - temporary merge table locking Use of a temporary *Note `MERGE': merge-storage-engine. table with nontemporary children could corrupt the children. Temporary tables are never locked. Creation of tables with nontemporary children of a temporary *Note `MERGE': merge-storage-engine. table is now prohibited. * Bug#27660 - `Falcon': *Note `MERGE': merge-storage-engine. table possible It was possible to create a *Note `MERGE': merge-storage-engine. table with non-`MyISAM' children. * Bug#30273 - *Note `MERGE': merge-storage-engine. tables: Can't lock file (errno: 155) This was a Windows-only bug. Table administration statements sometimes failed with "Can't lock file (errno: 155)". The fix introduces the following changes in behavior: * This patch changes the behavior of temporary *Note `MERGE': merge-storage-engine. tables. Temporary *Note `MERGE': merge-storage-engine. must have temporary children. The old behavior was wrong. A temporary table is not locked. Hence even nontemporary children were not locked. See Bug #19627. * You cannot change the union list of a nontemporary *Note `MERGE': merge-storage-engine. table when *Note `LOCK TABLES': lock-tables. is in effect. The following does _not_ work: CREATE TABLE m1 ... ENGINE=MRG_MYISAM ...; LOCK TABLES t1 WRITE, t2 WRITE, m1 WRITE; ALTER TABLE m1 ... UNION=(t1,t2) ...; However, you can do this with a temporary *Note `MERGE': merge-storage-engine. table. * You cannot create a *Note `MERGE': merge-storage-engine. table with `CREATE ... SELECT', neither as a temporary *Note `MERGE': merge-storage-engine. table, nor as a nontemporary *Note `MERGE': merge-storage-engine. table. For example, `CREATE TABLE m1 ... ENGINE=MRG_MYISAM ... SELECT ...;' causes the error message: `table is not BASE TABLE'. (Bug #19627, Bug #25038, Bug #25700, Bug #26377, Bug #26379, Bug #26867, Bug #27660, Bug #30275, Bug #30491) * *Important Change*: *MySQL Cluster*: `AUTO_INCREMENT' columns had the following problems when used in *Note `NDB': mysql-cluster. tables: * The `AUTO_INCREMENT' counter was not updated correctly when such a column was updated. * `AUTO_INCREMENT' values were not prefetched beyond statement boundaries. * `AUTO_INCREMENT' values were not handled correctly with *Note `INSERT IGNORE': insert. statements. * After being set, `ndb_autoincrement_prefetch_sz' showed a value of 1, regardless of the value it had actually been set to. As part of this fix, the behavior of `ndb_autoincrement_prefetch_sz' has changed. Setting this to less than 32 no longer has any effect on prefetching within statements (where IDs are now always obtained in batches of 32 or more), but only between statements. The default value for this variable has also changed, and is now `1'. (Bug #25176, Bug #31956, Bug #32055) * *Partitioning*: *Important Note*: An apostrophe or single quote character (`'') used in the `DATA DIRECTORY', `INDEX DIRECTORY', or `COMMENT' for a `PARTITION' clause caused the server to crash. When used as part of a *Note `CREATE TABLE': create-table. statement, the crash was immediate. When used in an *Note `ALTER TABLE': alter-table. statement, the crash did not occur until trying to perform a *Note `SELECT': select. or DML statement on the table. In either case, the server could not be completely restarted until the `.frm' file corresponding to the newly created or altered table was deleted. *Note*: Upgrading to the current (or later) release solves this problem only for tables that are newly created or altered. Tables created or altered in previous versions of the server to include `'' characters in `PARTITION' options must still be removed by deleting the corresponding `.frm' files and re-creating them afterward. (Bug #30695) * *Important Note*: The `RENAME DATABASE' statement was removed and replaced with `ALTER DATABASE DB_NAME UPGRADE DATA DIRECTORY NAME'. The `RENAME DATABASE' statement was intended for upgrading database directory names to the encoding format used in 5.1 for representing identifiers in the file system (see *Note identifier-mapping::). However, the statement was found to be dangerous because it could result in loss of database contents. See *Note rename-database::, and *Note alter-database::. (Bug #17565, Bug #21741, Bug #28360) * *Replication*: *MySQL Cluster*: Row-based replication from or to a big-endian machine where the table used the *Note `NDB': mysql-cluster. storage engine failed, if the same table on the other machine was either non-*Note `NDB': mysql-cluster. or the other machine was little-endian. (Bug #29549, Bug #30790) See also Bug #24231, Bug #30024, Bug #30133, Bug #30134. * *MySQL Cluster*: An improperly reset internal signal was observed as a hang when using events in the *Note `NDB': mysql-cluster. API but could result in various errors. (Bug #33206) * *MySQL Cluster*: Incorrectly handled parameters could lead to a crash in the Transaction Coordinator during a node failure, causing other data nodes to fail. (Bug #33168) * *MySQL Cluster*: A memory leak occurred if a subscription start request was received by the subscription manager before the node making the request was fully connected to the cluster. (Bug #32652) * *MySQL Cluster*: A local checkpoint could sometimes be started before the previous LCP was restorable from a global checkpoint. (Bug #32519) * *MySQL Cluster*: High numbers of API nodes on a slow or congested network could cause connection negotiation to time out prematurely, leading to the following issues: * Excessive retries * Excessive CPU usage * Partially connected API nodes (Bug #32359) * *MySQL Cluster*: When a *Note `mysqld': mysqld. acting as a cluster SQL node starts the *Note `NDBCLUSTER': mysql-cluster. storage engine, there is a delay during which some necessary data structures cannot be initialized until after it has connected to the cluster, and all MySQL Cluster tables should be opened as read only. This worked correctly when the *Note `NDB': mysql-cluster. binlog thread was running, but when it was not running, Cluster tables were not opened as read only even when the data structures had not yet been set up. (Bug #32275, Bug #33763) * *MySQL Cluster*: The failure of a master node could lead to subsequent failures in local checkpointing. (Bug #32160) * *MySQL Cluster*: The management server was slow to respond when no data nodes were connected to the cluster. This was most noticeable when running *Note `SHOW': show. in the management client. (Bug #32023) * *MySQL Cluster*: An error with an `if' statement in `sql/ha_ndbcluster.cc' could potentially lead to an infinite loop in case of failure when working with `AUTO_INCREMENT' columns in *Note `NDB': mysql-cluster. tables. (Bug #31810) * *MySQL Cluster*: The *Note `NDB': mysql-cluster. storage engine code was not safe for strict-alias optimization in `gcc' 4.2.1. (Bug #31761) * *MySQL Cluster*: It was possible in some cases for a node group to be `lost' due to missed local checkpoints following a system restart. (Bug #31525) * *MySQL Cluster*: A query against a table with *Note `TEXT': blob. or *Note `BLOB': blob. columns that would return more than a certain amount of data failed with `Got error 4350 'Transaction already aborted' from NDBCLUSTER'. (Bug #31482) This regression was introduced by Bug #29102. * *MySQL Cluster*: *Note `NDB': mysql-cluster. tables having names containing nonalphanumeric characters (such as ``$'') were not discovered correctly. (Bug #31470) * *MySQL Cluster*: A node failure during a local checkpoint could lead to a subsequent failure of the cluster during a system restart. (Bug #31257) * *MySQL Cluster*: A cluster restart could sometimes fail due to an issue with table IDs. (Bug #30975) * *MySQL Cluster*: When handling *Note `BLOB': blob. columns, the addition of read locks to the lock queue was not handled correctly. (Bug #30764) * *MySQL Cluster*: Discovery of *Note `NDB': mysql-cluster. tables did not work correctly with `INFORMATION_SCHEMA'. (Bug #30667) * *MySQL Cluster*: A file system close operation could fail during a node or system restart. (Bug #30646) * *MySQL Cluster*: Transaction timeouts were not handled well in some circumstances, leading to excessive number of transactions being aborted unnecessarily. (Bug #30379) * *MySQL Cluster*: The cluster management client could not connect, and would hang instead. This issue affected Mac OS X 64-bit only. (Bug #30366) * *MySQL Cluster*: Attempting to restore a backup made on a cluster host using one endian to a machine using the other endian could cause the cluster to fail. (Bug #29674) * *MySQL Cluster*: Log event requests to *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. could time out, causing it to fail. (Bug #29621) * *MySQL Cluster*: In some cases, the cluster managment server logged entries multiple times following a restart of *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. (Bug #29565) * *MySQL Cluster*: *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. `--help' did not display any information about the `-a' option. (Bug #29509) * *MySQL Cluster*: An interpreted program of sufficient size and complexity could cause all cluster data nodes to shut down due to buffer overruns. (Bug #29390) * *MySQL Cluster*: *Note `ndb_size.pl': mysql-cluster-programs-ndb-size-pl. failed on tables with *Note `FLOAT': numeric-types. columns whose definitions included commas (for example, `FLOAT(6,2)'). (Bug #29228) * *MySQL Cluster*: The error message for *Note `NDB': mysql-cluster. error code 275 (`Out of transaction records for complete phase') was missing. (Bug #29139) * *MySQL Cluster*: Reads on *Note `BLOB': blob. columns were not locked when they needed to be to guarantee consistency. (Bug #29102) See also Bug #31482. * *MySQL Cluster*: A query using joins between several large tables and requiring unique index lookups failed to complete, eventually returning `Uknown Error' after a very long period of time. This occurred due to inadequate handling of instances where the Transaction Coordinator ran out of `TransactionBufferMemory', when the cluster should have returned NDB error code 4012 (`Request ndbd time-out'). (Bug #28804) * *MySQL Cluster*: There was a short interval during the startup process prior to the beginning of heartbeat detection such that, were an API or management node to reboot or a network failure to occur, data nodes could not detect this, with the result that there could be a lingering connection. (Bug #28445) * *MySQL Cluster*: The description of the `--print' option provided in the output from *Note `ndb_restore `--help' ': mysql-cluster-programs-ndb-restore. was incorrect. (Bug #27683) * *MySQL Cluster*: Restoring a backup made on a cluster host using one endian to a machine using the other endian failed for *Note `BLOB': blob. and *Note `DATETIME': datetime. columns. (Bug #27543, Bug #30024) * *MySQL Cluster*: An invalid subselect on an *Note `NDB': mysql-cluster. table could cause *Note `mysqld': mysqld. to crash. (Bug #27494) * *MySQL Cluster*: An attempt to perform a `SELECT ... FROM INFORMATION_SCHEMA.TABLES' whose result included information about *Note `NDB': mysql-cluster. tables for which the user had no privileges crashed the MySQL Server on which the query was performed. (Bug #26793) * *MySQL Cluster*: Performing *Note `DELETE': delete. operations after a data node had been shut down could lead to inconsistent data following a restart of the node. (Bug #26450) * *MySQL Cluster*: `UPDATE IGNORE' could sometimes fail on *Note `NDB': mysql-cluster. tables due to the use of unitialized data when checking for duplicate keys to be ignored. (Bug #25817) * *MySQL Cluster*: The cluster log was formatted inconsistently and contained extraneous newline characters. (Bug #25064) * *MySQL Cluster*: A restart of the cluster failed when more than 1 REDO phase was in use. (Bug #22696) * *MySQL Cluster*: When inserting a row into an *Note `NDB': mysql-cluster. table with a duplicate value for a nonprimary unique key, the error issued would reference the wrong key. This improves on an initial fix for this issue made in MySQL 5.1.13. (Bug #21072) * *MySQL Cluster*: An insufficiently descriptive and potentially misleading Error 4006 (`Connect failure - out of connection objects...') was produced when either of the following two conditions occurred: 1. There were no more transaction records in the transaction coordinator 2. An *Note `NDB': mysql-cluster. object in the NDB API was initialized with insufficient parallelism Separate error messages are now generated for each of these two cases. (Bug #11313) * *Partitioning*: *Replication*: Replication of partitioned tables using the `InnoDB' storage engine failed with `binlog-format=ROW' or `binlog-format=MIXED'. (Bug #28430) * *Partitioning*: It was possible to partition a table to which a foreign key referred. (Bug #32948) * *Partitioning*: A query of the form `SELECT COL1 FROM TABLE GROUP BY (SELECT COL2 FROM TABLE LIMIT 1);' against a partitioned TABLE having a `SET' column crashed the server. (Bug #32772) * *Partitioning*: *Note `SHOW CREATE TABLE': show-create-table. misreported the value of `AUTO_INCREMENT' for partitioned tables using either of the `InnoDB' or `ARCHIVE' storage engines. (Bug #32247) * *Partitioning*: Selecting from *Note `INFORMATION_SCHEMA.PARTITIONS': partitions-table. while partition management statements (for example, `ALTER TABLE ... ADD PARTITION') were executing caused the server to crash. (Bug #32178) * *Partitioning*: An error in the internal function `mysql_unpack_partition()' led to a fatal error in subsequent calls to `open_table_from_share()'. (Bug #32158) * *Partitioning*: Repeated updates of a table that was partitioned by `KEY' on a *Note `TIMESTAMP': datetime. column eventually crashed the server. (Bug #32067) * *Partitioning*: Changing the storage engine used by a table having subpartitions led to a server crash. (Bug #31893) * *Partitioning*: `ORDER BY ... DESC' did not always work correctly when selecting from partitioned tables. (Bug #31890) See also Bug #31001. * *Partitioning*: Selecting from a table partitioned by `KEY' on a *Note `VARCHAR': char. column whose size was greater than 65530 caused the server to crash. (Bug #31705) * *Partitioning*: *Note `INSERT DELAYED': insert-delayed. on a partitioned table crashed the server. The server now rejects the statement with an error. (Bug #31210) * *Partitioning*: Using *Note `ALTER TABLE': alter-table. to partition an existing table having an `AUTO_INCREMENT' column could crash the server. (Bug #30878) This regression was introduced by Bug #27405. * *Partitioning*: `ALTER TABLE ... COALESCE PARTITION' on a table partitioned by `[LINEAR] HASH' or `[LINEAR] KEY' caused the server to crash. (Bug #30822) * *Partitioning*: `LIKE' queries on tables partitioned by `KEY' and using third-party storage engines could return incomplete results. (Bug #30480) See also Bug #29320, Bug #29493, Bug #30563. * *Partitioning*: It was not possible to insert the greatest possible value for a given data type into a partitioned table. For example, consider a table defined as shown here: CREATE TABLE t (c BIGINT UNSIGNED) PARTITION BY RANGE(c) ( PARTITION p0 VALUES LESS THAN MAXVALUE ); The largest possible value for a `BIGINT UNSIGNED' column is 18446744073709551615, but the statement `INSERT INTO t VALUES (18446744073709551615);' would fail, even though the same statement succeeded were `t' not a partitioned table. In other words, `MAXVALUE' was treated as being equal to the greatest possible value, rather than as a least upper bound. (Bug #29258) * *Cluster Replication*: *Replication*: A node failure during replication could lead to buckets out of order; now active subscribers are checked for, rather than empty buckets. (Bug #31701) * *Cluster Replication*: *Replication*: Incorrect handling of *Note `INSERT': insert. plus *Note `DELETE': delete. operations with regard to local checkpoints caused data node failures in multi-master replication setups. (Bug #30914) * *Replication*: When dropping a database containing a stored procedure while using row-cased replication, the delete of the stored procedure from the `mysql.proc' table was recorded in the binary log following the *Note `DROP DATABASE': drop-database. statement. To correct this issue, *Note `DROP DATABASE': drop-database. now uses statement-based replication. (Bug #32435) * *Replication*: It was possible for the name of the relay log file to exceed the amount of memory reserved for it, possibly leading to a crash of the server. (Bug #31836) See also Bug #28597. * *Replication*: Corruption of log events caused the server to crash on 64-bit Linux systems having 4 GB or more of memory. (Bug #31793) * *Replication*: Trying to replicate an update of a row that was missing on the slave led to a failure on the slave. (Bug #31702) * *Replication*: Use of the `@@hostname' system variable in inserts in `mysql_system_tables_data.sql' did not replicate. The workaround is to select its value into a user variable (which does replicate) and insert that. (Bug #31167) * *Replication*: Table names were displayed as binary `garbage' characters in slave error messages. The issue was observed on 64-bit Windows but may have effected other platforms. (Bug #30854) * *Replication*: One thread could read uninitialized memory from the stack of another thread. This issue was only known to occur in a *Note `mysqld': mysqld. process acting as both a master and a slave. (Bug #30752) * *Replication*: It was possible to set `SQL_SLAVE_SKIP_COUNTER' such that the slave would jump into the middle of a transaction. This fix improves on one made for this bug in MySQL 5.1.20; the previous fix insured that the slave could not be made to jump into the middle of an event group, but the slave failed to recognize that *Note `BEGIN': commit, *Note `COMMIT': commit, and *Note `ROLLBACK': commit. statements could begin or end an event group. (Bug #28618) See also Bug #12691. * *Replication*: Due a previous change in how the default name and location of the binary log file were determined, replication failed following some upgrades. (Bug #28597, Bug #28603) See also Bug #31836. This regression was introduced by Bug #20166. * *Replication*: Stored procedures having *Note `BIT': numeric-types. parameters were not replicated correctly. (Bug #26199) * *Replication*: Issuing *Note `SHOW SLAVE STATUS': show-slave-status. as *Note `mysqld': mysqld. was shutting down could cause a crash. (Bug #26000) * *Replication*: If a temporary error occurred inside an event group on an event that was not the first event of the group, the slave could get caught in an endless loop because the retry counter was reset whenever an event was executed successfully. (Bug #24860) See also Bug #12691, Bug #23171. * *Replication*: An *Note `UPDATE': update. statement using a stored function that modified a nontransactional table was not logged if it failed. This caused the copy of the nontransactional table on the master have a row that the copy on the slave did not. In addition, when an *Note `INSERT ... ON DUPLICATE KEY UPDATE': insert-on-duplicate. statement encountered a duplicate key constraint, but the *Note `UPDATE': update. did not actually change any data, the statement was not logged. As a result of this fix, such statements are now treated the same for logging purposes as other *Note `UPDATE': update. statements, and so are written to the binary log. (Bug #23333) See also Bug #12713. * *Replication*: A replication slave sometimes failed to reconnect because it was unable to run *Note `SHOW SLAVE HOSTS': show-slave-hosts. It was not necessary to run this statement on slaves (since the master should track connection IDs), and the execution of this statement by slaves was removed. (Bug #21132) See also Bug #13963, Bug #21869. * *Replication*: A replication slave sometimes stopped for changes that were idempotent (that is, such changes should have been considered `safe'), even though it should have simply noted that the change was already done, and continued operation. (Bug #19958) * *Replication*: Replicating from a master table to a slave table where the size of a *Note `CHAR': char. or *Note `VARCHAR': char. column was a different size would cause *Note `mysqld': mysqld. to crash. For more information on replicating with different column definitions, see *Note replication-features-differing-tables::. * *Cluster Replication*: A replication slave could return `garbage' data that was not in recognizable row format due to a problem with the internal `all_set()' method. (Bug #33375) * *Cluster Replication*: Memory was mistakenly freed for `NdbBlob' objects when adding an index while replicating the cluster, which could cause *Note `mysqld': mysqld. to crash. (Bug #33142) See also Bug #18106. * *Cluster Replication*: Under certain conditions, the slave stopped processing relay logs. This resulted in the logs never being cleared and the slave eventually running out of disk space. (Bug #31958) * *Cluster Replication*: Replicating *Note `NDB': mysql-cluster. tables with extra *Note `VARCHAR': char. columns on the master caused the slave to fail. (Bug #31646) See also Bug #29549. * *Cluster Replication*: When the master *Note `mysqld': mysqld. crashed or was restarted, no `LOST_EVENTS' entry was made in the binlog. (Bug #31484) See also Bug #21494. * *Cluster Replication*: An issue with the `mysql.ndb_apply_status' table could cause *Note `NDB': mysql-cluster. schema autodiscovery to fail in certain rare circumstances. (Bug #20872) * *Cluster API*: A call to `CHECK_TIMEDOUT_RET()' in `mgmapi.cpp' should have been a call to `DBUG_CHECK_TIMEDOUT_RET()'. (Bug #30681) * *API*: When the language option was not set correctly, API programs calling *Note `mysql_server_init()': mysql-server-init. crashed. This issue was observed only on Windows platforms. (Bug #31868) * Corrected a typecast involving `bool' on Mac OS X 10.5 (Leopard), which evaluated differently from earlier Mac OS X versions. (Bug #38217) * Use of uninitialized memory for `filesort' in a subquery caused a server crash. (Bug #33675) * *Note `CREATE TABLE ... SELECT': create-table. created tables that for date columns used the obsolete `Field_date' type instead of `Field_newdate'. (Bug #33256) * Some valid *Note `SELECT': select. statements could not be used as views due to incorrect column reference resolution. (Bug #33133) * The fix for Bug#11230 and Bug#26215 introduced a significant input-parsing slowdown for the *Note `mysql': mysql. client. This has been corrected. (Bug #33057) * The correct data type for a `NULL' column resulting from a *Note `UNION': union. could be determined incorrectly in some cases: 1) Not correctly inferred as `NULL' depending on the number of selects; 2) Not inferred correctly as `NULL' if one select used a subquery. (Bug #32848) * For queries containing `GROUP_CONCAT(DISTINCT COL_LIST ORDER BY COL_LIST)', there was a limitation that the `DISTINCT' columns had to be the same as `ORDER BY' columns. Incorrect results could be returned if this was not true. (Bug #32798) * *Note `SHOW EVENTS': show-events. and selecting from the *Note `INFORMATION_SCHEMA.EVENTS': events-table. table failed if the current database was `INFORMATION_SCHEMA'. (Bug #32775) * Use of the `cp932' character set with `CAST()' in an `ORDER BY' clause could cause a server crash. (Bug #32726) * A subquery using an `IS NULL' check of a column defined as `NOT NULL' in a table used in the `FROM' clause of the outer query produced an invalid result. (Bug #32694) * *Note `mysqld_safe': mysqld-safe. looked for error messages in the wrong location. (Bug #32679) * Specifying a nonexistent column for an *Note `INSERT DELAYED': insert-delayed. statement caused a server crash rather than producing an error. (Bug #32676) * An issue with the `NO_ENGINE_SUBSTITUTION' `sql_mode' database can cause the creation of stored routines to fail. If you are having problems with creating stored routines while using this `sql_mode' value, remove this value from your `sql_mode' setting. (Bug #32633) * Use of `CLIENT_MULTI_QUERIES' caused `libmysqld' to crash. (Bug #32624) * The `INTERVAL()' function incorrectly handled `NULL' values in the value list. (Bug #32560) * Use of a `NULL'-returning `GROUP BY' expression in conjunction with `WITH ROLLUP' could cause a server crash. (Bug #32558) See also Bug #31095. * `ORDER BY UpdateXML(...)' caused the server to crash in queries where `UpdateXML()' returned `NULL'. (Bug #32557) * A `SELECT ... GROUP BY BIT_COLUMN' query failed with an assertion if the length of the *Note `BIT': numeric-types. column used for the `GROUP BY' was not an integer multiple of 8. (Bug #32556) * Using `SELECT INTO OUTFILE' with 8-bit `ENCLOSED BY' characters led to corrupted data when the data was reloaded using LOAD DATA INFILE. This was because `SELECT INTO OUTFILE' failed to escape the 8-bit characters. (Bug #32533) * For *Note `FLUSH TABLES WITH READ LOCK': flush, the server failed to properly detect write-locked tables when running with low-priority updates, resulting in a crash or deadlock. (Bug #32528) * The rules for valid column names were being applied differently for base tables and views. (Bug #32496) * A query of the form `SELECT @USER_VARIABLE := CONSTANT AS ALIAS FROM TABLE GROUP BY ALIAS WITH ROLLUP' crashed the server. (Bug #32482) * Sending several *Note `KILL QUERY': kill. statements to target a connection running `SELECT SLEEP()' could freeze the server. (Bug #32436) * `ssl-cipher' values in option files were not being read by `libmysqlclient'. (Bug #32429) * Repeated execution of a query containing a *Note `CASE': case-statement. expression and numerous `AND' and `OR' relations could crash the server. The root cause of the issue was determined to be that the internal `SEL_ARG' structure was not properly initialized when created. (Bug #32403) * Referencing within a subquery an alias used in the *Note `SELECT': select. list of the outer query was incorrectly permitted. (Bug #32400) * If a global read lock acquired with *Note `FLUSH TABLES WITH READ LOCK': flush. was in effect, executing *Note `ALTER TABLE': alter-table. could cause a server crash. (Bug #32395) * An `ORDER BY' query on a view created using a `FEDERATED' table as a base table caused the server to crash. (Bug #32374) * Comparison of a `BIGINT NOT NULL' column with a constant arithmetic expression that evaluated to NULL mistakenly caused the error `Column '...' cannot be null' (error 1048). (Bug #32335) * Assigning a 65,536-byte string to a *Note `TEXT': blob. column (which can hold a maximum of 65,535 bytes) resulted in truncation without a warning. Now a truncation warning is generated. (Bug #32282) * The `LAST_DAY()' function returns a *Note `DATE': datetime. value, but internally the value did not have the time fields zeroed and calculations involving the value could return incorrect results. (Bug #32270) * `MIN()' and `MAX()' could return incorrect results when an index was present if a loose index scan was used. (Bug #32268) * Some uses of user variables in a query could result in a server crash. (Bug #32260) * Memory corruption could occur due to large index map in `Range checked for each record' status reported by *Note `EXPLAIN SELECT': explain. The problem was based in an incorrectly calculated length of the buffer used to store a hexadecimal representation of an index map, which could result in buffer overrun and stack corruption under some circumstances. (Bug #32241) * Various test program cleanups were made: 1) `mytest' and `libmysqltest' were removed. 2) `bug25714' displays an error message when invoked with incorrect arguments or the `--help' option. 3) `mysql_client_test' exits cleanly with a proper error status. (Bug #32221) * The default grant tables on Windows contained information for host `production.mysql.com', which should not be there. (Bug #32219) * Under certain conditions, the presence of a `GROUP BY' clause could cause an `ORDER BY' clause to be ignored. (Bug #32202) * For comparisons of the form DATE_COL OP DATETIME_CONST (where OP is `=', `<', `>', `<=', or `>='), the comparison is done using *Note `DATETIME': datetime. values, per the fix for Bug#27590. However that fix caused any index on DATE_COL not to be used and compromised performance. Now the index is used again. (Bug #32198) * *Note `DATETIME': datetime. arguments specified in numeric form were treated by `DATE_ADD()' as *Note `DATE': datetime. values. (Bug #32180) * Killing a statement could lead to a race condition in the server. (Bug #32148) * `InnoDB' does not support `SPATIAL' indexes, but could crash when asked to handle one. Now an error is returned. (Bug #32125) * The server crashed on optimizations involving a join of *Note `INT': numeric-types. and *Note `MEDIUMINT': numeric-types. columns and a system variable in the `WHERE' clause. (Bug #32103) * `mysql-test-run.pl' used the `--user' option when starting *Note `mysqld': mysqld, which produces warnings if the current user is not `root'. Now `--user' is added only for `root'. (Bug #32078) * *Note `mysqlslap': mysqlslap. was missing from the MySQL 5.1.22 Linux RPM packages. (Bug #32077) * With `lower_case_table_names' set, `CREATE TABLE LIKE' was treated differently by `libmysqld' than by the nonembedded server. (Bug #32063) * Within a subquery, *Note `UNION': union. was handled differently than at the top level, which could result in incorrect results or a server crash. (Bug #32036, Bug #32051) * On 64-bit platforms, assignments of values to enumeration-valued storage engine-specific system variables were not validated and could result in unexpected values. (Bug #32034) * A *Note `DELETE': delete. statement with a subquery in the `WHERE' clause would sometimes ignore an error during subquery evaluation and proceed with the delete operation. (Bug #32030) * Using dates in the range `'0000-00-01'' to `'0000-00-99'' range in the `WHERE' clause could result in an incorrect result set. (These dates are not in the supported range for *Note `DATE': datetime, but different results for a given query could occur depending on position of records containing the dates within a table.) (Bug #32021) * User-defined functions are not loaded if the server is started with the `--skip-grant-tables' option, but the server did not properly handle this case and issued an `Out of memory' error message instead. (Bug #32020) * If a user-defined function was used in a *Note `SELECT': select. statement, and an error occurred during UDF initialization, the error did not terminate execution of the *Note `SELECT': select, but rather was converted to a warning. (Bug #32007) * `HOUR()', `MINUTE()', and `SECOND()' could return nonzero values for *Note `DATE': datetime. arguments. (Bug #31990) * Changing the SQL mode to cause dates with `zero' parts to be considered invalid (such as `'1000-00-00'') could result in indexed and nonindexed searches returning different results for a column that contained such dates. (Bug #31928) * The server used unnecessarily large amounts of memory when user variables were used as an argument to `CONCAT()' or `CONCAT_WS()'. (Bug #31898) * In debug builds, testing the result of an `IN' subquery against `NULL' caused an assertion failure. (Bug #31884) * `mysql-test-run.pl' sometimes set up test scenarios in which the same port number was passed to multiple servers, causing one of them to be unable to start. (Bug #31880) * *Note `SHOW CREATE TRIGGER': show-create-trigger. caused a server crash. (Bug #31866) * The server crashed after insertion of a negative value into an `AUTO_INCREMENT' column of an `InnoDB' table. (Bug #31860) * For `libmysqld' applications, handling of *Note `mysql_change_user()': mysql-change-user. calls left some pointers improperly updated, leading to server crashes. (Bug #31850) * Using `ORDER BY' led to the wrong result when using the `ARCHIVE' on a table with a *Note `BLOB': blob. when the table cache was full. The table could also be reported as crashed after the query had completed, even though the table data was intact. (Bug #31833) * Comparison results for `BETWEEN' were different from those for operators like `<' and `>' for *Note `DATETIME': datetime.-like values with trailing extra characters such as `'2007-10-01 00:00:00 GMT-6''. `BETWEEN' treated the values as *Note `DATETIME': datetime, whereas the other operators performed a binary-string comparison. Now they all uniformly use a *Note `DATETIME': datetime. comparison, but generate warnings for values with trailing garbage. (Bug #31800) * Name resolution for correlated subqueries and `HAVING' clauses failed to distinguish which of two was being performed when there was a reference to an outer aliased field. This could result in error messages about a `HAVING' clause for queries that had no such clause. (Bug #31797) * The server could crash during `filesort' for `ORDER BY' based on expressions with `INET_NTOA()' or `OCT()' if those functions returned `NULL'. (Bug #31758) * For tables with certain definitions, *Note `UPDATE': update. statements could fail to find the correct record to update and report an error when the record did in fact exist. (Bug #31747) * For a fatal error during a filesort in `find_all_keys()', the error was returned without the necessary handler uninitialization, causing an assertion failure. (Bug #31742) * *Note `mysqlslap': mysqlslap. failed to commit after the final record load. (Bug #31704) * The examined-rows count was not incremented for `const' queries. (Bug #31700) * The server crashed if a thread was killed while locking the `general_log' table at the beginning of statement processing. (Bug #31692) * The *Note `mysql_change_user()': mysql-change-user. C API function was subject to buffer overflow. (Bug #31669) * For *Note `SELECT ... INTO OUTFILE': select, if the `ENCLOSED BY' string is empty and the `FIELDS TERMINATED BY' string started with a special character (one of `n', `t', `r', `b', `0', `Z', or `N'), every occurrence of the character within field values would be duplicated. (Bug #31663) * *Note `SHOW COLUMNS': show-columns. and *Note `DESCRIBE': describe. displayed `null' as the column type for a view with no valid definer. This caused *Note `mysqldump': mysqldump. to produce a nonreloadable dump file for the view. (Bug #31662) * The *Note `mysqlbug': mysqlbug. script did not include the correct values of `CFLAGS' and `CXXFLAGS' that were used to configure the distribution. (Bug #31644) * Queries that include a comparison of an `INFORMATION_SCHEMA' table column to `NULL' caused a server crash. (Bug #31633) * *Note `EXPLAIN EXTENDED': explain. for *Note `SELECT': select. from `INFORMATION_SCHEMA' tables caused an assertion failure. (Bug #31630) * `ucs2' does not work as a client character set, but attempts to use it as such were not rejected. Now `character_set_client' cannot be set to `ucs2'. This also affects statements such as `SET NAMES' and `SET CHARACTER SET'. (Bug #31615) * A buffer used when setting variables was not dimensioned to accommodate the trailing `'\0'' byte, so a single-byte buffer overrun was possible. (Bug #31588) * `HAVING' could treat lettercase of table aliases incorrectly if `lower_case_table_names' was enabled. (Bug #31562) * Spurious duplicate-key errors could occur for multiple-row inserts into an `InnoDB' table that activate a trigger. (Bug #31540) * Using *Note `ALTER EVENT': alter-event. to rename a disabled event caused it to become enabled. (Bug #31539) * The fix for Bug#24989 introduced a problem such that a `NULL' thread handler could be used during a rollback operation. This problem is unlikely to be seen in practice. (Bug #31517) * The length of the result from `IFNULL()' could be calculated incorrectly because the sign of the result was not taken into account. (Bug #31471) * Queries that used the `ref' access method or index-based subquery execution over indexes that have *Note `DECIMAL': numeric-types. columns could fail with an error `Column COL_NAME cannot be null'. (Bug #31450) * `InnoDB' now tracks locking and use of tables by MySQL only after a table has been successfully locked on behalf of a transaction. Previously, the locked flag was set and the table in-use counter was updated before checking whether the lock on the table succeeded. A subsequent failure in obtaining a lock on the table led to an inconsistent state as the table was neither locked nor in use. (Bug #31444) * `SELECT 1 REGEX NULL' caused an assertion failure for debug servers. (Bug #31440) * The `UpdateXML()' function did not check for the validity of all its arguments; in some cases, this could lead to a crash of the server. (Bug #31438) * The *Note `mysql_change_user()': mysql-change-user. C API function caused advisory locks (obtained with `GET_LOCK()') to malfunction. (Bug #31418) * NDB libraries and include files were missing from some binary `tar' file distributions. (Bug #31414) * Executing `RENAME' while tables were open for use with *Note `HANDLER': handler. statements could cause a server crash. (Bug #31409) * `mysql-test-run.pl' tried to create files in a directory where it could not be expected to have write permission. `mysqltest' created `.reject' files in a directory other than the one where test results go. (Bug #31398) * For a table that had been opened with *Note `HANDLER': handler. and marked for reopening after being closed with *Note `FLUSH TABLES': flush, *Note `DROP TABLE': drop-table. did not properly discard the handler. (Bug #31397) * Automatically allocated memory for string options associated with a plugin was not freed if the plugin did not get installed. (Bug #31382) * *Note `INFORMATION_SCHEMA.TABLES': tables-table. was returning incorrect information. (Bug #31381) * *Note `DROP USER': drop-user. caused an increase in memory usage. (Bug #31347) * For `InnoDB' tables with `READ COMMITTED' isolation level, semi-consistent reads used for *Note `UPDATE': update. statements skipped rows locked by another transaction, rather than waiting for the locks to be released. Consequently, rows that possibly should have been updated were never examined. (Bug #31310) * For an almost-full `MyISAM' table, an insert that failed could leave the table in a corrupt state. (Bug #31305) * *Note `myisamchk --unpack': myisamchk. could corrupt a table that when unpacked has static (fixed-length) row format. (Bug #31277) * `CONVERT(VAL, DATETIME)' would fail on invalid input, but processing was not aborted for the `WHERE' clause, leading to a server crash. (Bug #31253) * Allocation of an insufficiently large group-by buffer following creation of a temporary table could lead to a server crash. (Bug #31249) * Use of `DECIMAL(N, N) ZEROFILL' in `GROUP_CONCAT()' could cause a server crash. (Bug #31227) * When a *Note `TIMESTAMP': datetime. with a nonzero time part was converted to a *Note `DATE': datetime. value, no warning was generated. This caused index lookups to assume that this is a valid conversion and was returning rows that match a comparison between a *Note `TIMESTAMP': datetime. value and a *Note `DATE': datetime. keypart. Now a warning is generated so that *Note `TIMESTAMP': datetime. with a nonzero time part will not match *Note `DATE': datetime. values. (Bug #31221) * Server variables could not be set to their current values on Linux platforms. (Bug #31177) See also Bug #6958. * With small values of `myisam_sort_buffer_size', *Note `REPAIR TABLE': repair-table. for `MyISAM' tables could cause a server crash. (Bug #31174) * If `MAKETIME()' returned `NULL' when used in an `ORDER BY' that was evaluated using `filesort', a server crash could result. (Bug #31160) * Data in *Note `BLOB': blob. or `GEOMETRY' columns could be cropped when performing a *Note `UNION': union. query. (Bug #31158) * `LAST_INSERT_ID()' execution could be handled improperly in subqueries. (Bug #31157) * An assertion designed to detect a bug in the `ROLLUP' implementation would incorrectly be triggered when used in a subquery context with noncacheable statements. (Bug #31156) * Selecting spatial types in a *Note `UNION': union. could cause a server crash. (Bug #31155) * Use of `GROUP_CONCAT(DISTINCT BIT_COLUMN)' caused an assertion failure. (Bug #31154) * The server crashed in the parser when running out of memory. Memory handling in the parser has been improved to gracefully return an error when out-of-memory conditions occur in the parser. (Bug #31153) * MySQL declares a `UNIQUE' key as a `PRIMARY' key if it doesn't have `NULL' columns and is not a partial key, and the `PRIMARY' key must alway be the first key. However, in some cases, a nonfirst key could be reported as `PRIMARY', leading to an assert failure by `InnoDB'. This is fixed by correcting the key sort order. (Bug #31137) * *Note `mysqldump': mysqldump. failed to handle databases containing a ``-'' character in the name. (Bug #31113) * Starting the server using `--read-only' and with the Event Scheduler enabled caused it to crash. *Note*: This issue occurred only when the server had been built with certain nonstandard combinations of `configure' options. (Bug #31111) * `GROUP BY NULL WITH ROLLUP' could cause a server crash. (Bug #31095) See also Bug #32558. * A rule to prefer `filesort' over an indexed `ORDER BY' when accessing all rows of a table was being used even if a `LIMIT' clause was present. (Bug #31094) * `REGEXP' operations could cause a server crash for character sets such as `ucs2'. Now the arguments are converted to `utf8' if possible, to permit correct results to be produced if the resulting strings contain only 8-bit characters. (Bug #31081) * Expressions of the form `WHERE COL NOT IN (COL, ...)', where the same column was named both times, could cause a server crash in the optimizer. (Bug #31075) * Internal conversion routines could fail for several multi-byte character sets (`big5', `cp932', `euckr', `gb2312', `sjis') for empty strings or during evaluation of `SOUNDS LIKE'. (Bug #31069, Bug #31070) * Many nested subqueries in a single query could led to excessive memory consumption and possibly a crash of the server. (Bug #31048) * Using `ORDER BY' with `ARCHIVE' tables caused a server crash. (Bug #31036) * A server crash could occur when a non-`DETERMINISTIC' stored function was used in a `GROUP BY' clause. (Bug #31035) * The `MOD()' function and the `%' operator crashed the server for a divisor less than 1 with a very long fractional part. (Bug #31019) * Transactions were committed prematurely when *Note `LOCK TABLE': lock-tables. and `SET autocommit = 0' were used together. (Bug #30996) * On Windows, the `pthread_mutex_trylock()' implementation was incorrect. (Bug #30992) * A character set introducer followed by a hexadecimal or bit-value literal did not check its argument and could return an ill-formed result for invalid input. (Bug #30986) * `CHAR(STR USING CHARSET)' did not check its argument and could return an ill-formed result for invalid input. (Bug #30982) * The result from `CHAR(STR USING ucs2') did not add a leading 0x00 byte for input strings with an odd number of bytes. (Bug #30981) * The `GeomFromText()' function could cause a server crash if the first argument was `NULL' or the empty string. (Bug #30955) * `MAKEDATE()' incorrectly moved year values in the 100 to 200 range into the 1970 to 2069 range. (This is legitimate for 00 to 99, but three-digit years should be used unchanged.) (Bug #30951) * When invoked with constant arguments, `STR_TO_DATE()' could use a cached value for the format string and return incorrect results. (Bug #30942) * `GROUP_CONCAT()' returned `','' rather than an empty string when the argument column contained only empty strings. (Bug #30897) * For `MEMORY' tables, lookups for `NULL' values in `BTREE' indexes could return incorrect results. (Bug #30885) * A server crash could occur if a stored function that contained a `DROP TEMPORARY TABLE' statement was invoked by a *Note `CREATE TEMPORARY TABLE': create-table. statement that created a table of the same name. (Bug #30882) * Calling `NAME_CONST()' with nonconstant arguments triggered an assertion failure. Nonconstant arguments are no longer permitted. (Bug #30832) * For a spatial column with a regular (non-`SPATIAL') index, queries failed if the optimizer tried to use the index. (Bug #30825) * Values for the `--tc-heuristic-recover' option incorrectly were treated as values for the `--myisam-stats-method' option. (Bug #30821) * *Note `INFORMATION_SCHEMA.SCHEMATA': schemata-table. was returning incorrect information. (Bug #30795) * The optimizer incorrectly optimized conditions out of the `WHERE' clause in some queries involving subqueries and indexed columns. (Bug #30788) * Improper calculation of `CASE' expression results could lead to value truncation. (Bug #30782) * On Windows, the `pthread_mutex_trylock()' implementation was incorrect. One symptom was that invalidating the query cache could cause a server crash. (Bug #30768) * A multiple-table *Note `UPDATE': update. involving transactional and nontransactional tables caused an assertion failure. (Bug #30763) * User-supplied names foreign key names might not be set to the right key, leading to foreign keys with no name. (Bug #30747) * Under some circumstances, *Note `CREATE TABLE ... SELECT': create-table. could crash the server or incorrectly report that the table row size was too large. (Bug #30736) * Using the `MIN()' or `MAX()' function to select one part of a multi-part key could cause a crash when the function result was `NULL'. (Bug #30715) * The embedded server did not properly check column-level privileges. (Bug #30710) * `INFORMATION_SCHEMA.VIEWS.VIEW_DEFINITION' was incorrect for views that were defined to select from other `INFORMATION_SCHEMA' tables. (Bug #30689) * Issuing an *Note `ALTER SERVER': alter-server. statement to update the settings for a `FEDERATED' server would cause the *Note `mysqld': mysqld. to crash. (Bug #30671) * The optimizer could ignore `ORDER BY' in cases when the result set is ordered by `filesort', resulting in rows being returned in incorrect order. (Bug #30666) * A different execution plan was displayed for *Note `EXPLAIN': explain. than would actually have been used for the *Note `SELECT': select. because the test of sort keys for `ORDER BY' did not consider keys mentioned in `IGNORE KEYS FOR ORDER BY'. (Bug #30665) * The `thread_handling' system variable was treated as having a `SESSION' value and as being settable at runtime. Now it has only a `GLOBAL' read-only value. (Bug #30651) * On Windows, `LIMIT' arguments greater than 2^32 did not work correctly. (Bug #30639) * `MyISAM' tables could not exceed 4294967295 (2^32 - 1) rows on Windows. (Bug #30638) * A failed `HANDLER ... READ' operation could leave the table in a locked state. (Bug #30632) * `mysql-test-run.pl' could not run *Note `mysqld': mysqld. with `root' privileges. (Bug #30630) * The *Note `mysqld_safe': mysqld-safe. script contained a syntax error. (Bug #30624) * The optimization that uses a unique index to remove `GROUP BY' did not ensure that the index was actually used, thus violating the `ORDER BY' that is implied by `GROUP BY'. (Bug #30596) * `SHOW STATUS LIKE 'Ssl_cipher_list'' from a MySQL client connected using SSL returned an empty string rather than a list of available ciphers. (Bug #30593) * For `MEMORY' tables, *Note `DELETE': delete. statements that remove rows based on an index read could fail to remove all matching rows. (Bug #30590) * Using `GROUP BY' on an expression of the form `TIMESTAMP_COL DIV NUMBER' caused a server crash due to incorrect calculation of number of decimals. (Bug #30587) * Executing a `SELECT COUNT(*)' query on an `InnoDB' table partitioned by `KEY' that used a *Note `DOUBLE': numeric-types. column as the partitioning key caused the server to crash. (Bug #30583) * The options available to the *Note `CHECK TABLE': check-table. statement were also permitted in *Note `OPTIMIZE TABLE': optimize-table. and *Note `ANALYZE TABLE': analyze-table. statements, but caused corruption during their execution. These options were never supported for these statements, and an error is now raised if you try to apply these options to these statements. (Bug #30495) * A self-referencing trigger on a partitioned table caused the server to crash instead of failing with an error. (Bug #30484) * The *Note `mysql_change_user()': mysql-change-user. C API function did not correctly reset the character set variables to the values they had just after initially connecting. (Bug #30472) * When expanding a `*' in a `USING' or `NATURAL' join, the check for table access for both tables in the join was done using only the grant information of the first table. (Bug #30468) * When casting a string value to an integer, cases where the input string contained a decimal point and was long enough to overrun the `unsigned long long' type were not handled correctly. The position of the decimal point was not taken into account which resulted in miscalculated numbers and incorrect truncation to appropriate SQL data type limits. (Bug #30453) * Versions of *Note `mysqldump': mysqldump. from MySQL 4.1 or higher tried to use `START TRANSACTION WITH CONSISTENT SNAPSHOT' if the `--single-transaction' and `--master-data' options were given, even with servers older than 4.1 that do not support consistent snapshots. (Bug #30444) * With `libmysqld', use of prepared statements and the query cache at the same time caused problems. (Bug #30430) * Issuing a *Note `DELETE': delete. statement having both an `ORDER BY' clause and a `LIMIT' clause could cause *Note `mysqld': mysqld. to crash. (Bug #30385) * For `CREATE ... SELECT ... FROM', where the resulting table contained indexes, adding `SQL_BUFFER_RESULT' to the *Note `SELECT': select. part caused index corruption in the table. (Bug #30384) * The `Last_query_cost' status variable value can be computed accurately only for simple `flat' queries, not complex queries such as those with subqueries or *Note `UNION': union. However, the value was not consistently being set to 0 for complex queries. (Bug #30377) * The optimizer made incorrect assumptions about the value of the `is_member' value for user-defined functions, sometimes resulting in incorrect ordering of UDF results. (Bug #30355) * Queries that had a `GROUP BY' clause and selected `COUNT(DISTINCT BIT_COLUMN)' returned incorrect results. (Bug #30324) * Some valid `euc-kr' characters having the second byte in the ranges `[0x41..0x5A]' and `[0x61..0x7A]' were rejected. (Bug #30315) * When loading a dynamic plugin on FreeBSD, the plugin would fail to load. This was due to a build error where the required symbols would be not exported correctly. (Bug #30296) * Simultaneous *Note `ALTER TABLE': alter-table. statements for `BLACKHOLE' tables caused 100% CPU use due to locking problems. (Bug #30294) * Setting certain values on a table using a spatial index could cause the server to crash. (Bug #30286) * Tables with a `GEOMETRY' column could be marked as corrupt if you added a non-`SPATIAL' index on a `GEOMETRY' column. (Bug #30284) * Flushing a merge table between the time it was opened and its child table were actually attached caused the server to crash. (Bug #30273) This regression was introduced by Bug #26379. * The query cache does not support retrieval of statements for which column level access control applies, but the server was still caching such statements, thus wasting memory. (Bug #30269) * Using `DISTINCT' or `GROUP BY' on a *Note `BIT': numeric-types. column in a *Note `SELECT': select. statement caused the column to be cast internally as an integer, with incorrect results being returned from the query. (Bug #30245) * `GROUP BY' on *Note `BIT': numeric-types. columns produced incorrect results. (Bug #30219) * Short-format *Note `mysql': mysql. commands embedded within `/*! ... */' comments were parsed incorrectly by *Note `mysql': mysql, which discarded the rest of the comment including the terminating `*/' characters. The result was a malformed (unclosed) comment. Now *Note `mysql': mysql. does not discard the `*/' characters. (Bug #30164) * If the server crashed during an *Note `ALTER TABLE': alter-table. statement, leaving a temporary file in the database directory, a subsequent *Note `DROP DATABASE': drop-database. statement failed due to the presence of the temporary file. (Bug #30152) * When *Note `mysqldump': mysqldump. wrote *Note `DROP DATABASE': drop-database. statements within version-specific comments, it included the terminating semicolon in the wrong place, causing following statements to fail when the dump file was reloaded. (Bug #30126) * It was not possible for client applications to distinguish between auto-set and auto-updated *Note `TIMESTAMP': datetime. column values. To rectify this problem, a new `ON_UPDATE_NOW_FLAG' flag is set by Field_timestamp constructors whenever a column should be set to `NOW' on *Note `UPDATE': update, and the `get_schema_column_record()' function now reports whether a timestamp column is set to `NOW' on *Note `UPDATE': update. In addition, such columns now display `on update CURRENT_TIMESTAMP' in the `Extra' column in the output from *Note `SHOW COLUMNS': show-columns. (Bug #30081) * Some `INFORMATION_SCHEMA' tables are intended for internal use, but could be accessed by using *Note `SHOW': show. statements. (Bug #30079) * On some 64-bit systems, inserting the largest negative value into a *Note `BIGINT': numeric-types. column resulted in incorrect data. (Bug #30069) * *Note `mysqlslap': mysqlslap. did not properly handle multiple result sets from stored procedures. (Bug #29985) * Specifying the `--without-geometry' option for `configure' caused server compilation to fail. (Bug #29972) * Statements within stored procedures ignored the value of the `low_priority_updates' system variable. (Bug #29963) See also Bug #26162. * With auto-reconnect enabled, row fetching for a prepared statement could crash after reconnect occurred because loss of the statement handler was not accounted for. (Bug #29948) * *Note `mysqldump': mysqldump. `--skip-events' `--all-databases' dumped data from the `mysqld.event' table, and when restoring from this dump, events were created in spite of the `--skip-events' option. (Bug #29938) * When *Note `mysqlslap': mysqlslap. was given a query to execute from a file using a `--query=FILE_NAME ' option, it executed the query one too many times. (Bug #29803) * `configure' did not find `nss' on some Linux platforms. (Bug #29658) * It was possible when creating a partitioned table using *Note `CREATE TABLE ... SELECT': create-table. to refer in the `PARTITION BY' clause to columns in the table being selected from, which could cause the server to crash. An example of such a statement is: CREATE TABLE t1 (b INT) PARTITION BY RANGE(t2.b) ( PARTITION p1 VALUES LESS THAN (10), PARTITION p2 VALUES LESS THAN (20) ) SELECT * FROM t2; The fix is to disallow references in `PARTITION BY' clauses to columns not in the table being created. (Bug #29444) * If a view used a function in its *Note `SELECT': select. statement, the columns from the view were not inserted into the *Note `INFORMATION_SCHEMA.COLUMNS': columns-table. table. (Bug #29408) * The *Note `mysql': mysql. client program now ignores Unicode byte order mark (BOM) characters at the beginning of input files. Previously, it read them and sent them to the server, resulting in a syntax error. Presence of a BOM does not cause *Note `mysql': mysql. to change its default character set. To do that, invoke *Note `mysql': mysql. with an option such as `--default-character-set=utf8'. (Bug #29323) * For transactional tables, an error during a multiple-table *Note `DELETE': delete. statement did not roll back the statement. (Bug #29136) * The `log' and `log_slow_queries' system variables were displayed by *Note `SHOW VARIABLES': show-variables. but could not be accessed in expressions as `@@log' and `@@log_slow_queries'. Also, attempting to set them with *Note `SET': set-option. produced an incorrect `Unknown system variable' message. Now these variables are treated as synonyms for `general_log' and `slow_query_log', which means that they can be accessed in expressions and their values can be changed with *Note `SET': set-option. (Bug #29131) * Denormalized double-precision numbers cannot be handled properly by old MIPS pocessors. For IRIX, this is now handled by enabling a mode to use a software workaround. (Bug #29085) * *Note `SHOW VARIABLES': show-variables. did not display the `relay_log', `relay_log_index', or `relay_log_info_file' system variables. (Bug #28893) * When doing a *Note `DELETE': delete. on a table that involved a `JOIN' with *Note `MyISAM': myisam-storage-engine. or *Note `MERGE': merge-storage-engine. tables and the `JOIN' referred to the same table, the operation could fail reporting `ERROR 1030 (HY000): Got error 134 from storage engine'. This was because scans on the table contents would change because of rows that had already been deleted. (Bug #28837) * Killing an SSL connection on platforms where MySQL is compiled with `-DSIGNAL_WITH_VIO_CLOSE' (Windows, Mac OS X, and some others) could crash the server. (Bug #28812) * *Note `SHOW VARIABLES': show-variables. did not correctly display the value of the `thread_handling' system variable. (Bug #28785) * On Windows, *Note `mysql_upgrade': mysql-upgrade. created temporary files in `C:\' and did not clean them up. (Bug #28774) * Index hints specified in view definitions were ignored when using the view to select from the base table. (Bug #28702) * Views do not have indexes, so index hints do not apply. Use of index hints when selecting from a view is no longer permitted. (Bug #28701) * After changing the SQL mode to a restrictive value that would make already-inserted dates in a column be considered invalid, searches returned different results depending on whether the column was indexed. (Bug #28687) * When running the MySQL Instance Configuration Wizard, a race condition could exist that would fail to connect to a newly configured instance. This was because *Note `mysqld': mysqld. had not completed the startup process before the next stage of the installation process. (Bug #28628) * A *Note `SELECT': select. in one connection could be blocked by *Note `INSERT ... ON DUPLICATE KEY UPDATE': insert-on-duplicate. in another connection even when `low_priority_updates' is set. (Bug #28587) * *Note `mysql_upgrade': mysql-upgrade. could run binaries dynamically linked against incorrect versions of shared libraries. (Bug #28560) * The result from `CHAR()' was incorrectly assumed in some contexts to return a single-byte result. (Bug #28550) * *Note `mysqldump': mysqldump. reversed the event name and program name in one of its error messages. (Bug #28535) * The parser confused user-defined function (UDF) and stored function creation for *Note `CREATE FUNCTION': create-function. and required that there be a default database when creating UDFs, although there is no such requirement. (Bug #28318, Bug #29816) * Fast-mutex locking was not thread-safe and optimization-safe on some platforms, which could cause program failures such as out-of-memory errors. (Bug #28284) * The result of a comparison between *Note `VARBINARY': binary-varbinary. and *Note `BINARY': binary-varbinary. columns differed depending on whether the *Note `VARBINARY': binary-varbinary. column was indexed. (Bug #28076) * The metadata in some `MYSQL_FIELD' members could be incorrect when a temporary table was used to evaluate a query. (Bug #27990) * Partition pruning was not used for queries having `<=' or `>=' conditions in the `WHERE' clause on a table using `TO_DAYS()' in the partitioning expression. (Bug #27927) * *Note `mysqlbinlog': mysqlbinlog. produced incorrectly formatted *Note `DATETIME': datetime. and *Note `TIMESTAMP': datetime. values. (Bug #27894) * Failure to log to the `general_log' or `slow_log' log tables were not logged to the error log at all or were logged incorrectly. (Bug #27858) * An `ORDER BY' at the end of a *Note `UNION': union. affected individual *Note `SELECT': select. statements rather than the overall query result. (Bug #27848) * *Note `comp_err': comp-err. created files with permissions such that they might be inaccessible during `make install' operations. (Bug #27789) * *Note `SHOW COLUMNS': show-columns. returned `NULL' instead of the empty string for the `Default' value of columns that had no default specified. (Bug #27747) * With recent versions of DBD::mysql, *Note `mysqlhotcopy': mysqlhotcopy. generated table names that were doubly qualified with the database name. (Bug #27694) * The anonymous accounts were not being created during MySQL installation. (Bug #27692) * Some *Note `SHOW': show. statements and `INFORMATION_SCHEMA' queries could expose information not permitted by the user's access privileges. An implication of this change is that *Note `SHOW TRIGGERS': show-triggers. and the *Note `INFORMATION_SCHEMA.TRIGGERS': triggers-table. table require the `TRIGGER' privilege, not `SUPER'. (Bug #27629) * `ALTER TABLE TBL_NAME ROW_FORMAT=FORMAT_TYPE' did not cause the table to be rebuilt. (Bug #27610) * A race condition between killing a statement and the thread executing the statement could lead to a situation such that the binary log contained an event indicating that the statement was killed, whereas the statement actually executed to completion. (Bug #27571) * Some character mappings in the `ascii.xml' file were incorrect. As a result of this bug fix, indexes must be rebuilt for columns that use the `ascii_general_ci' collation for columns that contain any of these characters: `'`'', `'['', `'\'', `']'', `'~''. See *Note checking-table-incompatibilities::. (Bug #27562) * Some queries using the `NAME_CONST()' function failed to return either a result or an error to the client, causing it to hang. This was due to the fact that there was no check to insure that both arguments to this function were constant expressions. (Bug #27545, Bug #32559) * With the `read_only' system variable enabled, *Note `CREATE DATABASE': create-database. and *Note `DROP DATABASE': drop-database. were permitted to users who did not have the `SUPER' privilege. (Bug #27440) * For an event with an `ON COMPLETION' value of `PRESERVE', an *Note `ALTER EVENT': alter-event. statement that specified no `ON COMPLETION' option caused the value to become `NOT PRESERVE'. (Bug #27407) * MySQL failed to generate or retrieve an `AUTO_INCREMENT' primary key for `InnoDB' tables with user-defined partitioning. (Bug #27405) * Changes to the `sql_mode' system variable were not tracked by *Note `INSERT DELAYED': insert-delayed. (Bug #27358) * A *Note `SELECT': select. with more than 31 nested dependent subqueries returned an incorrect result. (Bug #27352) * The `ExtractValue()' and `UpdateXML()' functions performed extremely slowly for large amounts of XML data (greater than 64 KB). These functions now execute approximately 2000 times faster than previously. (Bug #27287) * On Windows, writes to the debug log were using `freopen()' instead of `fflush()', resulting in slower performance. (Bug #27099) * For a table that used different full-text parsers for different `FULLTEXT' indexes, *Note `SHOW CREATE TABLE': show-create-table. displayed the first parser name for all of them. (Bug #27040) * `STR_TO_DATE()' displayed an error message that referred to `STR_TO_TIME()'. (Bug #27014) * The *Note `mysql_insert_id()': mysql-insert-id. C API function sometimes returned different results for `libmysqld' and `libmysqlclient'. (Bug #26921) * Symbolic links on Windows could fail to work. (Bug #26811) * *Note `mysqld': mysqld. sometimes miscalculated the number of digits required when storing a floating-point number in a *Note `CHAR': char. column. This caused the value to be truncated, or (when using a debug build) caused the server to crash. (Bug #26788) See also Bug #12860. * *Note `LOAD DATA INFILE': load-data. ran very slowly when reading large files into partitioned tables. (Bug #26527) * It makes no sense to attempt to use `ALTER TABLE ... ORDER BY' to order an `InnoDB' table if there is a user-defined clustered index, because rows are always ordered by the clustered index. Such attempts now are ignored and produce a warning. Also, in some cases, `InnoDB' incorrectly used a secondary index when the clustered index would produce a faster scan. *Note `EXPLAIN': explain. output now indicates use of the clustered index (for tables that have one) as lines with a `type' value of `index', a `key' value of `PRIMARY', and without `Using index' in the `Extra' value. (Bug #26447) See also Bug #35850. * Using *Note `HANDLER': handler. to open a table having a storage engine not supported by *Note `HANDLER': handler. properly returned an error, but also improperly prevented the table from being dropped by other connections. (Bug #25856) * For a prepared statement STMT, changing the default database following `PREPARE STMT' but before `EXECUTE STMT' caused STMT to be recorded incorrectly in the binary log. (Bug #25843) * `CREATE TABLE LIKE' did not work when the source table was an `INFORMATION_SCHEMA' table. (Bug #25629) * Threads that were calculating the estimated number of records for a range scan did not respond to the *Note `KILL': kill. statement. That is, if a `range' join type is possible (even if not selected by the optimizer as a join type of choice and thus not shown by *Note `EXPLAIN': explain.), the query in the `statistics' state (shown by the *Note `SHOW PROCESSLIST': show-processlist.) did not respond to the *Note `KILL': kill. statement. (Bug #25421) * For `InnoDB' tables, *Note `CREATE TABLE a AS SELECT * FROM A': create-table-select. would fail. (Bug #25164) * For *Note `mysql --show-warnings': mysql, warnings were in some cases not displayed. (Bug #25146) * The `returns' column of the `mysql.proc' table was `CHAR(64)', which is not long enough to store long data types such as *Note `ENUM': enum. types. The column has been changed to *Note `LONGBLOB': blob. and a warning is generated if truncation occurs when storing a row into the `proc' table. (Bug #24923) * If the expected precision of an arithmetic expression exceeded the maximum precision supported by MySQL, the precision of the result was reduced by an unpredictable or arbitrary amount, rather than to the maximum precision. In some cases, exceeding the maximum supported precision could also lead to a crash of the server. (Bug #24907) * For Vista installs, `MySQLInstanceConfig.exe' did not add the default MySQL port to the firewall exceptions. It now provides a check box that enables the user a choice of whether to do this. (Bug #24853) * A *Note `CREATE TRIGGER': create-trigger. statement could cause a deadlock or server crash if it referred to a table for which a table lock had been acquired with *Note `LOCK TABLES': lock-tables. (Bug #23713) * For storage engines that do not redefine `handler::index_next_same()' and are capable of indexes, statements that include a `WHERE' clause might select incorrect data. (Bug #22351) * The parser treated the `INTERVAL()' function incorrectly, leading to situations where syntax errors could result depending on which side of an arithmetic operator the function appeared. (Bug #22312) * Entries in the general query log were truncated at 1000 characters. (Bug #21557) * A memory leak occurred when `CREATE TEMPORARY TABLE .. SELECT' was invoked from a stored function that in turn was called from *Note `CREATE TABLE ... SELECT': create-table. (Bug #21136) * It was possible to execute `CREATE TABLE t1 ... SELECT ... FROM t2' with the `CREATE' privilege for `t1' and `SELECT' privilege for `t2', even in the absence of the `INSERT' privilege for `t1'. (Bug #20901) * Worked around an `icc' problem with an incorrect machine instruction being generated in the context of software pre-fetching after a subroutine got in-lined. (Upgrading to `icc' 10.0.026 makes the workaround unnecessary.) (Bug #20803) * If a column selected by a view referred to a stored function, the data type reported for the column in *Note `INFORMATION_SCHEMA.COLUMNS': columns-table. could be incorrect. (Bug #20550) * The *Note `mysql_change_user()': mysql-change-user. C API function changed the value of the `sql_big_selects' session variable. (Bug #20023) See also Bug #40363. * Host names sometimes were treated as case sensitive in account-management statements (*Note `CREATE USER': create-user, *Note `GRANT': grant, *Note `REVOKE': revoke, and so forth). (Bug #19828) * Issuing an SQL *Note `KILL': kill. of the active connection caused an error on Mac OS X. (Bug #19723) * The `readline' library has been updated to version 5.2. This addresses issues in the *Note `mysql': mysql. client where history and editing within the client would fail to work as expected. (Bug #18431) * The `-lmtmalloc' library was removed from the output of *Note `mysql_config': mysql-config. on Solaris, as it caused problems when building `DBD::mysql' (and possibly other applications) on that platform that tried to use `dlopen()' to access the client library. (Bug #18322) * `MySQLInstanceConfig.exe' failed to grant certain privileges to the `'root'@'%'' account. (Bug #17303) * The `Aborted_clients' status variable was incremented twice if a client exited without calling *Note `mysql_close()': mysql-close. (Bug #16918) * Use of *Note `GRANT': grant. statements with grant tables from an old version of MySQL could cause a server crash. (Bug #16470) * Clients were ignoring the TCP/IP port number specified as the default port using the `--with-tcp-port' configuration option. (Bug #15327) * Parameters of type *Note `DATETIME': datetime. or *Note `DATE': datetime. in stored procedures were silently converted to *Note `VARBINARY': binary-varbinary. (Bug #13675) * Zero-padding of exponent values was not the same across platforms. (Bug #12860) * Values of types `REAL ZEROFILL', `DOUBLE ZEROFILL', `FLOAT ZEROFILL', were not zero-filled when converted to a character representation in the C prepared statement API. (Bug #11589) * *Note `mysql': mysql. stripped comments from statements sent to the server. Now the `--comments' or `--skip-comments' option can be used to control whether to retain or strip comments. The default is `--skip-comments'. (Bug #11230, Bug #26215) * Several buffer-size system variables were either being handled incorrectly for large values (for settings larger than 4GB, they were truncated to values less than 4GB without a warning), or were limited unnecessarily to 4GB even on 64-bit systems. The following changes were made: * For `key_buffer_size', values larger than 4GB are permitted on 64-bit platforms. * For `join_buffer_size', `sort_buffer_size', and `myisam_sort_buffer_size', values larger than 4GB are permitted on 64-bit platforms (except Windows, for which large values are truncated to 4GB with a warning). In addition, settings for `read_buffer_size' and `read_rnd_buffer_size' are limited to 2GB on all platforms. Larger values are truncated to 2GB with a warning. (Bug #5731, Bug #29419, Bug #29446) * Executing `DISABLE KEYS' and `ENABLE KEYS' on a nonempty table would cause the size of the index file for the table to grow considerable. This was because the `DISABLE KEYS' operation would only mark the existing index, without deleting the index blocks. The `ENABLE KEYS' operation would re-create the index, adding new blocks, while the previous index blocks would remain. Existing indexes are now dropped and recreated when the `ENABLE KEYS' statement is executed. (Bug #4692) * Grant table checks failed in `libmysqld'.  File: manual.info, Node: news-5-1-22, Next: news-5-1-21, Prev: news-5-1-23, Up: news-5-1-x D.1.46 Changes in MySQL 5.1.22 (24 September 2007 Release Candidate) -------------------------------------------------------------------- *Functionality added or changed:* * There is a new `innodb_autoinc_lock_mode' system variable to configure the locking behavior that `InnoDB' uses for generating auto-increment values. The default behavior now is slightly different from before, which involves a minor incompatibility for multiple-row inserts that specify an explicit value for the auto-increment column in some but not all rows. See *Note innodb-auto-increment-handling::. *Bugs fixed:* * *MySQL Cluster*: *Replication*: (Replication): Multi-master replication setups did not handle `--log-slave-updates' correctly. (Bug #30017) * *MySQL Cluster*: Backups of *Note `TIMESTAMP': datetime. columns made with *Note `ndb_restore': mysql-cluster-programs-ndb-restore. on a MySQL Cluster using data nodes hosts of one endian could not be used to restore the cluster's data to data node hosts of the other endian. (Bug #30134) * *Replication*: Row-based replication from a pre-5.1.22 MySQL Server to a MySQL 5.1.22 was unstable due to an uninitialized variable. (Bug #31076) * *Replication*: Operations that used the time zone replicated the time zone only for successful operations, but did not replicate the time zone for errors that need to know it. (Bug #29536) * For an `InnoDB' table if a *Note `SELECT': select. was ordered by the primary key and also had a `WHERE field = value' clause on a different field that was indexed, a `DESC' order instruction would be ignored. (Bug #31001) * *Note `mysql_install_db': mysql-install-db. could fail to find its message file. (Bug #30678) * Memory corruption occurred for some queries with a top-level `OR' operation in the `WHERE' condition if they contained equality predicates and other sargable predicates in disjunctive parts of the condition. (Bug #30396) * `CONNECTION_ID()' always returned 0 for the embedded server (`libmysqld'). (Bug #30389) * The server created temporary tables for filesort operations in the working directory, not in the directory specified by the `tmpdir' system variable. (Bug #30287) * Using *Note `KILL QUERY': kill. or *Note `KILL CONNECTION': kill. to kill a *Note `SELECT': select. statement caused a server crash if the query cache was enabled. (Bug #30201) * *Note `mysqldump': mysqldump. from the MySQL 5.1.21 distribution could not be used to create a dump from a MySQL 5.1.20 or older server. (Bug #30123) * Under some circumstances, a UDF initialization function could be passed incorrect argument lengths. (Bug #29804) * When using a combination of `HANDLER... READ' and *Note `DELETE': delete. on a table, MySQL continued to open new copies of the table every time, leading to an exhaustion of file descriptors. (Bug #29474) This regression was introduced by Bug #21587. * The *Note `mysql_list_fields()': mysql-list-fields. C API function incorrectly set `MYSQL_FIELD::decimals' for some view columns. (Bug #29306) * Tables using the `InnoDB' storage engine incremented `AUTO_INCREMENT' values incorrectly with `ON DUPLICATE KEY UPDATE'. (Bug #28781) * Nonrange queries of the form `SELECT ... FROM ... WHERE KEYPART1=CONSTANT, ..., KEYPARTN=CONSTANT ORDER BY ... FOR UPDATE' sometimes were unnecessarily blocked waiting for a lock if another transaction was using *Note `SELECT ... FOR UPDATE': select. on the same table. (Bug #28570) * On Windows, symbols for yaSSL and taocrypt were missing from `mysqlclient.lib', resulting in unresolved symbol errors for clients linked against that library. (Bug #27861) * Read lock requests that were blocked by a pending write lock request were not permitted to proceed if the statement requesting the write lock was killed. (Bug #21281)  File: manual.info, Node: news-5-1-21, Next: news-5-1-20, Prev: news-5-1-22, Up: news-5-1-x D.1.47 Changes in MySQL 5.1.21 (16 August 2007) ----------------------------------------------- This is a new Beta development release, fixing recently discovered bugs. *Note*: This Beta release, as any other pre-production release, should not be installed on _production_ level systems or systems with critical data. It is good practice to back up your data before installing any new version of software. Although MySQL has worked very hard to ensure a high level of quality, protect your data by making a backup as you would for any software beta release. Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Note*: Subsequent to release, it was discovered that on some platforms, *Note `mysql_install_db': mysql-install-db. could fail to find its message file, resulting in error messages of the following form: shell> mysql_install_db Installing MySQL system tables... 070830 9:33:24 [ERROR] Can't find messagefile 'PATH/share/english/errmsg.sys' 070830 9:33:24 [ERROR] Aborting To deal with this problem, specify a `--language' option to specify the proper path name to the language file directory. For example: shell> mysql_install_db --language=/path/to/share/english/ This problem is corrected in MySQL 5.1.22. This section documents all changes and bug fixes that have been applied since the last official MySQL release. If you would like to receive more fine-grained and personalized _update alerts_ about fixes that are relevant to the version and features you use, please consider subscribing to _MySQL Enterprise_ (a commercial MySQL offering). For more details, please see http://www.mysql.com/products/enterprise. *Functionality added or changed:* * *Incompatible Change*: In MySQL 5.1.6, when log tables were implemented, the default log destination for the general query and slow query log was `TABLE'. This default has been changed to `FILE', which is compatible with MySQL 5.0, but incompatible with earlier releases of MySQL 5.1 from 5.1.6 to 5.1.20. If you are upgrading from MySQL 5.0 to 5.1.21 or higher, no logging option changes should be necessary. However, if you are upgrading from 5.1.6 through 5.1.20 to 5.1.21 or higher and were using `TABLE' logging, use the `--log-output=TABLE' option explicitly to preserve your server's table-logging behavior. A further fix for this issue was made in MySQL 5.1.23. (Bug #29993) * *Incompatible Change*: The `innodb_log_arch_dir' system variable (which has been deprecated since MySQL 5.0.24) has been removed and should no longer be used. * *Incompatible Change*: On Windows only, the *Note `mysqld-nt': mysqld. has been removed from this release and all future releases. The *Note `mysqld': mysqld. server now includes named-pipe support as standard, and you do not have to use the *Note `mysqld-nt': mysqld. version to enable named-pipe support. * *Important Change*: The default *Note `mysqld_safe': mysqld-safe. logging behavior now is `--skip-syslog' rather than `--syslog', which is compatible with the default behavior of writing an error log file for releases prior to 5.1.20. * *Replication*: The SQL thread on a slave now is always permitted to enter `InnoDB' even if this would exceed the limit imposed by the `innodb_thread_concurrency' system variable. In cases of high load on the slave server (when `innodb_thread_concurrency' is reached), this change helps the slave stay more up to date with the master; in the previous behavior, the SQL thread was competing for resources with all client threads active on the slave server. (Bug #25078) * *Replication*: Replication between master and slaves now supports different column numbers within a table on both master and slave. The rules for replication where the table definitions are different has also changed. This supercedes the functionality for replication from the master table to a slave table with more columns that was added in MySQL 5.1.12. For more information, see *Note replication-features-differing-tables::. * Several programs now accept `--debug-check' and `--debug-info' options: *Note `mysql': mysql, *Note `mysqladmin': mysqladmin, *Note `mysqlbinlog': mysqlbinlog, *Note `mysqlcheck': mysqlcheck, *Note `mysqldump': mysqldump, *Note `mysqlimport': mysqlimport, *Note `mysqlshow': mysqlshow, *Note `mysqlslap': mysqlslap, `mysqltest', *Note `mysql_upgrade': mysql-upgrade. (Note: *Note `mysql': mysql, *Note `mysqladmin': mysqladmin, *Note `mysqlcheck': mysqlcheck, *Note `mysqldump': mysqldump, *Note `mysqlimport': mysqlimport, *Note `mysqlshow': mysqlshow, and `mysqltest' already accepted `--debug-info'.) `--debug-check' prints debugging information at program exit. `--debug-info' is similar but also prints memory and CPU usage statistics. This patch also corrects a problem for *Note `mysql': mysql. that `--debug-info' did not display statistics at exit time. (Bug #30127) * The `--syslog' option that was introduced in 5.1.20 for *Note `mysqld_safe': mysqld-safe. (to send error output to `syslog') did not work correctly: Error output was buffered and not logged immediately. This has been corrected. In addition, some feature changes were made: * *Important*: The default *Note `mysqld_safe': mysqld-safe. logging behavior now is `--skip-syslog' rather than `--syslog', which is compatible with the default behavior of writing an error log file for releases prior to 5.1.20. * A new option, `--syslog-tag=TAG ', modifies the default tags written by *Note `mysqld_safe': mysqld-safe. and *Note `mysqld': mysqld. to syslog to be `mysqld_safe-TAG ' and `mysqld-TAG' rather than the default tags of `mysqld_safe' and `mysqld'. (Bug #29992) * Transaction support in the `FEDERATED' storage engine has been disabled due to issues with multiple active transactions and sessions on the same `FEDERATED' table. (Bug #29875) * Previously, prepared statements processed using *Note `PREPARE': prepare. and *Note `EXECUTE': execute. were not subject to caching in the query cache if they contained any `?' parameter markers. This limitation has been lifted. (Bug #29318) * It is now possible to set `long_query_time' in microseconds or to 0. Setting this value to 0 causes all queries to be recorded in the slow query log. Currently, fractional values can be used only when logging to files. We plan to provide this functionality for logging to tables when time-related data types are enhanced to support microsecond resolution. (Bug #25412) * `INFORMATION_SCHEMA' implementation changes were made that optimize certain types of queries for `INFORMATION_SCHEMA' tables so that they execute more quickly. *Note information-schema-optimization::, provides guidelines on how to take advantage of these optimizations by writing queries that minimize the need for the server to access the file system to obtain the information contained in `INFORMATION_SCHEMA' tables. By writing queries that enable the server to avoid directory scans or opening table files, you will obtain better performance. (Bug #19588) * Log table locking was redesigned, eliminating several lock-related problems: * Truncating `mysql.slow_log' in a stored procedure after use of a cursor caused the thread to lock. * Flushing a log table resulted in unnecessary warnings. * The server would hang when performing concurrent *Note `ALTER TABLE': alter-table. or *Note `TRUNCATE TABLE': truncate-table. statements against the log tables. * Changing the value of the `general_log' system variable while a global read lock was in place resulted in deadlock. The changes provide better-defined interface characteristics. See *Note log-destinations::. (Bug #17876, Bug #23044, Bug #25422, Bug #29129) * Added the `--commit', `--detach', `--post-system', and `--pre-system' options for *Note `mysqlslap': mysqlslap. * A new option, `--syslog-tag=TAG ', modifies the default tags written by *Note `mysqld_safe': mysqld-safe. and *Note `mysqld': mysqld. to syslog to be `mysqld_safe-TAG ' and `mysqld-TAG ' rather than the default tags of `mysqld_safe' and `mysqld'. * Two options relating to slow query logging have been added for *Note `mysqld': mysqld. `--log-slow-slave-statements' causes slow statements executed by a replication slave to be written to the slow query log; `min_examined_row_limit' can be used to cause queries which examine fewer than the stated number of rows not to be logged. *Bugs fixed:* * *Incompatible Change*: Failure to consider collation when comparing space characters could result in incorrect index entry order, leading to incorrect comparisons, inability to find some index values, misordered index entries, misordered `ORDER BY' results, or tables that *Note `CHECK TABLE': check-table. reports as having corrupt indexes. As a result of this bug fix, indexes must be rebuilt for columns that use any of these character sets: `eucjpms', `euc_kr', `gb2312', `latin7', `macce', `ujis'. See *Note checking-table-incompatibilities::. (Bug #29461) * *Incompatible Change*: Several issues were identified for stored programs (stored procedures and functions, triggers, and events) and views containing non-ASCII symbols. These issues involved conversion errors due to incomplete character set information when translating these objects to and from stored format, such as: * Parsing the original object definition so that it can be stored. * Compiling the stored definition into executable form when the object is invoked. * Retrieval of object definitions from `INFORMATION_SCHEMA' tables. * Displaying the object definition in *Note `SHOW': show. statements. This issue also affected *Note `mysqldump': mysqldump, which uses *Note `SHOW': show. The fix for the problems is to store character set information from the object creation context so that this information is available when the object needs to be used later. The context includes the client character set, the connection character set and collation, and the collation of the database with which the object is associated. As a result of the patch, several tables have new columns: * In the `mysql' database, the `proc' and `event' tables now have these columns: `character_set_client', `collation_connection', `db_collation', `body_utf8'. * In `INFORMATION_SCHEMA', the *Note `VIEWS': views-table. table now has these columns: `CHARACTER_SET_CLIENT', `COLLATION_CONNECTION'. The *Note `ROUTINES': routines-table, *Note `TRIGGERS': triggers-table, and *Note `EVENTS': events-table. tables now have these columns: `CHARACTER_SET_CLIENT', `COLLATION_CONNECTION', `DATABASE_COLLATION'. These columns store the session values of the `character_set_client' and `collation_connection' system variables, and the collation of the database with which the object is associated. The values are those in effect at object creation time. (The saved database collation is not the value of the `collation_database' system variable, which applies to the default database; the database that contains the object is not necessarily the default database.) Several *Note `SHOW': show. statements now display additional columns corresponding to the new table columns. These statements are: *Note `SHOW CREATE EVENT': show-create-event, *Note `SHOW CREATE FUNCTION': show-create-function, *Note `SHOW CREATE PROCEDURE': show-create-procedure, *Note `SHOW CREATE VIEW': show-create-view, *Note `SHOW EVENTS': show-events, *Note `SHOW FUNCTION STATUS': show-function-status, *Note `SHOW PROCEDURE STATUS': show-procedure-status, *Note `SHOW TRIGGERS': show-triggers. A new statement, *Note `SHOW CREATE TRIGGER': show-create-trigger. is introduced and is used by *Note `mysqldump': mysqldump. for producing *Note `CREATE TRIGGER': create-trigger. statements. Subsequent to the patch just described, it was discovered that the patch broke *Note `mysql_upgrade': mysql-upgrade.; this has been corrected. *Important*: The fixes for the problems just describe affect _all_ existing stored programs and views. (For example, you will see warnings about `no creation context.') To avoid warnings from the server about the use of old definitions from any release prior to 5.1.21, you should dump stored programs and views with *Note `mysqldump': mysqldump. after upgrading to 5.1.21, and then reload them to recreate them with new definitions. Invoke *Note `mysqldump': mysqldump. with a `--default-character-set' option that names the non-ASCII character set that was used for the definitions when the objects were originally created. For more information about upgrading stored programs, see *Note upgrading-from-previous-series::. (Bug #25221, Bug #21249, Bug #30027, Bug #16291, Bug #11986, Bug #25212, Bug #19443, Bug #30029) * *MySQL Cluster*: *Replication*: (Replication): Inconsistencies could occur between the master and the slave when replicating Disk Data tables. (Bug #19259, Bug #19227) * *MySQL Cluster*: `DELETE FROM TABLE WHERE PRIMARY_KEY IN (VALUE_LIST)', where the VALUE_LIST contained more than one value, called from an `AFTER DELETE' trigger on an *Note `NDB': mysql-cluster. table, caused *Note `mysqld': mysqld. to crash. (Bug #30337) * *MySQL Cluster*: When restarting a data node, queries could hang during that node's start phase 5, and continue only after the node had entered phase 6. (Bug #29364) * *MySQL Cluster*: Replica redo logs were inconsistently handled during a system restart. (Bug #29354) * *MySQL Cluster*: When a node failed to respond to a `COPY_GCI' signal as part of a global checkpoint, the master node was killed instead of the node that actually failed. (Bug #29331) * *MySQL Cluster*: An invalid comparison made during `REDO' validation that could lead to an `Error while reading REDO log' condition. (Bug #29118) * *MySQL Cluster*: The wrong data pages were sometimes invalidated following a global checkpoint. (Bug #29067) * *MySQL Cluster*: If at least 2 files were involved in `REDO' invalidation, then file 0 of page 0 was not updated and so pointed to an invalid part of the redo log. (Bug #29057) * *MySQL Cluster*: If a storage engine has its own logging capability, then any statement using both this engine and some other engine not having its own logging could not be correctly logged, due to the fact that entries from one engine could be logged before entries from the other engine were. This did not generate any error messages when it occurred. Now, if multiple storage engines are used in a statement and at least one of them has its own logging capability, then an error message is generated and the statement is not executed. *Note*: Currently, the only storage engine to have its own logging capability is *Note `NDBCLUSTER': mysql-cluster. (Bug #28722) * *MySQL Cluster*: Warnings and errors generated by *Note `ndb_config `--config-file=FILE'': mysql-cluster-programs-ndb-config. were sent to `stdout', rather than to `stderr'. (Bug #25941) * *MySQL Cluster*: When a cluster backup was terminated using the `ABORT BACKUP' command in the management client, a misleading error message `Backup aborted by application: Permanent error: Internal error' was returned. The error message returned in such cases now reads `Backup aborted by user request'. (Bug #21052) * *MySQL Cluster*: Large file support did not work in AIX server binaries. (Bug #10776) * *Replication*: The thread ID was not reset properly after execution of *Note `mysql_change_user()': mysql-change-user, which could cause replication failure when replicating temporary tables. (Bug #29734) * *Replication*: Storage engine error conditions in row-based replication were not correctly reported to the user. (Bug #29570) * *Replication*: *Note `INSERT DELAYED': insert-delayed. statements on a master server are replicated as non-`DELAYED' inserts on slaves (which is normal, to preserve serialization), but the inserts on the slave did not use concurrent inserts. Now *Note `INSERT DELAYED': insert-delayed. on a slave is converted to a concurrent insert when possible, and to a normal insert otherwise. (Bug #29152) * *Replication*: An error that happened inside *Note `INSERT': insert, *Note `UPDATE': update, or *Note `DELETE': delete. statements performed from within a stored function or trigger could cause inconsistency between master and slave servers. (Bug #27417) * *Replication*: Slave servers could incorrectly interpret an out-of-memory error from the master and reconnect using the wrong binary log position. (Bug #24192) * *Replication*: Using the `READ COMMITTED' transaction isolation level caused mixed and statement-based replication to fail. (Bug #23051) * *Disk Data*: Performing Disk Data schema operations during a node restart could cause forced shutdowns of other data nodes. (Bug #29501) * *Disk Data*: When dropping a page, the stack's bottom entry could sometime be left `cold' rather than `hot', violating the rules for stack pruning. (Bug #29176) * *Disk Data*: Disk data meta-information that existed in *Note `ndbd': mysql-cluster-programs-ndbd. might not be visible to *Note `mysqld': mysqld. (Bug #28720) * *Disk Data*: The number of free extents was incorrectly reported for some tablespaces. (Bug #28642) * *Cluster Replication*: When executing a statement where `binlog_format = statement', the result of the statement was logged both as a statement and as rows. (Bug #29222) * *Cluster Replication*: *Note `mysqld': mysqld. would segfault on startup when the *Note `NDB': mysql-cluster. storage engine was enabled and the default character set was a strictly multi-byte character set such as UCS2. This issue does _not_ apply to character sets that can contain single-byte characters in addition to multi-byte characters such as UTF-8. Additional issues remain with regard to the use of multi-byte character sets in MySQL Cluster Replication; see *Note mysql-cluster-replication-issues::, for more information. (Bug #27404) * Prepared statements containing `CONNECTION_ID()' could be written improperly to the binary log. (Bug #30200) * Use of local variables with non-ASCII names in stored procedures crashed the server. (Bug #30120) * On Windows, client libraries lacked symbols required for linking. (Bug #30118) * `--myisam-recover=''' (empty option value) did not disable `MyISAM' recovery. (Bug #30088) * For the `SHOW TABLE TYPES' statement, the server sent incorrect output to clients, possibly causing them to crash. (Bug #30036) * The `IS_UPDATABLE' column in the *Note `INFORMATION_SCHEMA.VIEWS': views-table. table was not always set correctly. (Bug #30020) * *Note `SHOW': show. statements were being written to the slow query log that should not have been. (Bug #30000) * `REPAIR TABLE ... USE_FRM' could corrupt tables. (Bug #29980) * For `MyISAM' tables on Windows, *Note `INSERT': insert, *Note `DELETE': delete, or *Note `UPDATE': update. followed by *Note `ALTER TABLE': alter-table. within *Note `LOCK TABLES': lock-tables. could cause table corruption. (Bug #29957) * *Note `LOCK TABLES': lock-tables. did not pre-lock tables used in triggers of the locked tables. Unexpected locking behavior and statement failures similar to `failed: 1100: Table 'XX' was not locked with LOCK TABLES' could result. (Bug #29929) * `INSERT ... VALUES(CONNECTION_ID(), ...)' statements were written to the binary log in such a way that they could not be properly restored. (Bug #29928) * Adding `DISTINCT' could cause incorrect rows to appear in a query result. (Bug #29911) * On Windows, the `CMake' build process did not produce the embedded server library or related binaries. (Bug #29903) * Using the `DATE()' function in a `WHERE' clause did not return any records after encountering `NULL'. However, using `TRIM()' or `CAST()' produced the correct results. (Bug #29898) * `SESSION_USER()' returned garbage data (rather than the correct value of the empty string) when executed by a slave SQL thread. (Bug #29878) * Very long prepared statements in stored procedures could cause a server crash. (Bug #29856) * If query execution involved a temporary table, `GROUP_CONCAT()' could return a result with an incorrect character set. (Bug #29850) * If one thread was performing concurrent inserts, other threads reading from the same table using equality key searches could see the index values for new rows before the data values had been written, leading to reports of table corruption. (Bug #29838) * Repeatedly accessing a view in a stored procedure (for example, in a loop) caused a small amount of memory to be allocated per access. Although this memory is deallocated on disconnect, it could be a problem for a long running stored procedures that make repeated access of views. (Bug #29834) * *Note `mysqldump': mysqldump. produced output that incorrectly discarded the `NO_AUTO_VALUE_ON_ZERO' value of the `sql_mode' variable after dumping triggers. (Bug #29788) * An assertion failure occurred within yaSSL for very long keys. (Bug #29784) See also Bug #53463. * For `MEMORY' tables, the `index_merge' union access method could return incorrect results. (Bug #29740) * Comparison of *Note `TIME': time. values using the `BETWEEN' operator led to string comparison, producing incorrect results in some cases. Now the values are compared as integers. (Bug #29739) * For a table with a *Note `DATE': datetime. column DATE_COL such that selecting rows with `WHERE DATE_COL = 'DATE_VAL 00:00:00'' yielded a nonempty result, adding `GROUP BY DATE_COL' caused the result to be empty. (Bug #29729) * In some cases, `INSERT INTO ... SELECT ... GROUP BY' could insert rows even if the *Note `SELECT': select. by itself produced an empty result. (Bug #29717) * Single-row inserts could report a row count greater than one. (Bug #29692) * For the embedded server, the *Note `mysql_stmt_store_result()': mysql-stmt-store-result. C API function caused a memory leak for empty result sets. (Bug #29687) * *Note `EXPLAIN': explain. produced `Impossible where' for statements of the form `SELECT ... FROM t WHERE c=0', where `c' was an *Note `ENUM': enum. column defined as a primary key. (Bug #29661) * On Windows, *Note `ALTER TABLE': alter-table. hung if records were locked in share mode by a long-running transaction. (Bug #29644) * *Note `mysqld_safe': mysqld-safe. produced error messages and did not create the error log file under some circumstances. (Bug #29634) * On 64-bit platforms, the filesort code (for queries with `GROUP BY' or `ORDER BY') could crash due to an incorrect pointer size. (Bug #29610) * A left join between two views could produce incorrect results. (Bug #29604) * Certain statements with unions, subqueries, and joins could result in huge memory consumption. (Bug #29582) * Clients using SSL could hang the server. (Bug #29579) * A slave running with `--log-slave-updates' would fail to write `INSERT DELAY IGNORE' statements to its binary log, resulting in different binary log contents on the master and slave. (Bug #29571) * An incorrect result was returned when comparing string values that were converted to *Note `TIME': time. values with `CAST()'. (Bug #29555) * `gcov' coverage-testing information was not written if the server crashed. (Bug #29543) * In the `ascii' character set, conversion of DEL (`0x7F') to Unicode incorrectly resulted in QUESTION MARK (`0x3F') rather than DEL. (Bug #29499) * A field packet with `NULL' fields caused a `libmysqlclient' crash. (Bug #29494) * On Windows, the *Note `mysql': mysql. client died if the user entered a statement and Return after entering `Control+C'. (Bug #29469) * The full-text parser could enter an infinite loop if it encountered an illegal multi-byte sequence or a sequence that has no mapping to Unicode. (Bug #29464) * Searching a `FULLTEXT' index for a word with the boolean mode truncation operator could cause an infinite loop. (Bug #29445) * Corrupt data resulted from use of `SELECT ... INTO OUTFILE 'FILE_NAME' FIELDS ENCLOSED BY 'C'', where C is a digit or minus sign, followed by `LOAD DATA INFILE 'FILE_NAME' FIELDS ENCLOSED BY 'C''. (Bug #29442) * Killing an *Note `INSERT DELAYED': insert-delayed. thread caused a server crash. (Bug #29431) * Use of *Note `SHOW BINLOG EVENTS': show-binlog-events. for a nonexistent log file followed by *Note `PURGE BINARY LOGS': purge-binary-logs. caused a server crash. (Bug #29420) * Assertion failure could occur for grouping queries that employed *Note `DECIMAL': numeric-types. user variables with assignments to them. (Bug #29417) * For `CAST(EXPR AS DECIMAL(M,D))', the limits of 65 and 30 on the precision (M) and scale (D) were not enforced. (Bug #29415) * Deleting from a `CSV' table could corrupt it. (Bug #29411) * Results for a select query that aliases the column names against a view could duplicate one column while omitting another. This bug could occur for a query over a multiple-table view that includes an `ORDER BY' clause in its definition. (Bug #29392) * *Note `mysqldump': mysqldump. created a stray file when a given a too-long file name argument. (Bug #29361) * The special `zero' *Note `ENUM': enum. value was coerced to the normal empty string *Note `ENUM': enum. value during a column-to-column copy. This affected `CREATE ... SELECT' statements and *Note `SELECT': select. statements with aggregate functions on *Note `ENUM': enum. columns in the `GROUP BY' clause. (Bug #29360) * Inserting a negative number into a `CSV' table could corrupt it. (Bug #29353) * Optimization of queries with `DETERMINISTIC' stored functions in the `WHERE' clause was ineffective: A sequential scan was always used. (Bug #29338) * `MyISAM' corruption could occur with the `cp932_japanese_ci' collation for the `cp932' character set due to incorrect comparison for trailing space. (Bug #29333) * For updates to `InnoDB' tables, a *Note `TIMESTAMP': datetime. column with the `ON UPDATE CURRENT_TIMESTAMP' attribute could be updated even when no values actually changed. (Bug #29310) * `FULLTEXT' indexes could be corrupted by certain `gbk' characters. (Bug #29299) * *Note `SELECT ... INTO OUTFILE': select. followed by *Note `LOAD DATA': load-data. could result in garbled characters when the `FIELDS ENCLOSED BY' clause named a delimiter of `'0'', `'b'', `'n'', `'r'', `'t'', `'N'', or `'Z'' due to an interaction of character encoding and doubling for data values containing the enclosed-by character. (Bug #29294) * Sort order of the collation wasn't used when comparing trailing spaces. This could lead to incorrect comparison results, incorrectly created indexes, or incorrect result set order for queries that include an `ORDER BY' clause. (Bug #29261) * *Note `CHECK TABLE': check-table. could erroneously report table corruption for a `CSV' table if multiple threads were modifying the table at the same time. (Bug #29253) * Many threads accessing a `CSV' table simultaneously could cause an assertion failure. (Bug #29252) * If an *Note `ENUM': enum. column contained `''' as one of its members (represented with numeric value greater than 0), and the column contained error values (represented as 0 and displayed as `'''), using *Note `ALTER TABLE': alter-table. to modify the column definition caused the 0 values to be given the numeric value of the nonzero `''' member. (Bug #29251) * Calling *Note `mysql_options()': mysql-options. after *Note `mysql_real_connect()': mysql-real-connect. could cause clients to crash. (Bug #29247) * *Note `CHECK TABLE': check-table. for `ARCHIVE' tables could falsely report table corruption or cause a server crash. (Bug #29207) * Mixing binary and `utf8' columns in a union caused field lengths to be calculated incorrectly, resulting in truncation. (Bug #29205) * `AsText()' could fail with a buffer overrun. (Bug #29166) * Under some circumstances, a `SELECT ... FROM mysql.event' could cause the server to crash. (Bug #29156) * `InnoDB' refused to start on some versions of FreeBSD with LinuxThreads. This is fixed by enabling file locking on FreeBSD. (Bug #29155) * *Note `LOCK TABLES': lock-tables. was not atomic when more than one `InnoDB' tables were locked. (Bug #29154) * *Note `mysqld': mysqld. failed to exit during shutdown. (Bug #29133) * A network structure was initialized incorrectly, leading to embedded server crashes. (Bug #29117) * An assertion failure occurred if a query contained a conjunctive predicate of the form ` VIEW_COLUMN = constant' in the `WHERE' clause and the `GROUP BY' clause contained a reference to a different view column. The fix also enables application of an optimization that was being skipped if a query contained a conjunctive predicate of the form `VIEW_COLUMN = constant' in the `WHERE' clause and the `GROUP BY' clause contained a reference to the same view column. (Bug #29104) * A maximum of 4TB `InnoDB' free space was reported by `SHOW TABLE STATUS,' which is incorrect on systems with more than 4TB space. (Bug #29097) * If an *Note `INSERT INTO ... SELECT': insert-select. statement inserted into the same table that the *Note `SELECT': select. retrieved from, and the *Note `SELECT': select. included `ORDER BY' and `LIMIT' clauses, different data was inserted than the data produced by the *Note `SELECT': select. executed by itself. (Bug #29095) * Queries that performed a lookup into a *Note `BINARY': binary-varbinary. index containing key values ending with spaces caused an assertion failure for debug builds and incorrect results for nondebug builds. (Bug #29087) * The semantics of *Note `BIGINT': numeric-types. depended on platform-specific characteristics. (Bug #29079) * A byte-order issue in writing a spatial index to disk caused bad index files on some systems. (Bug #29070) * Creation of a legal stored procedure could fail if no default database had been selected. (Bug #29050) * *Note `REPLACE': replace, *Note `INSERT IGNORE': insert, and `UPDATE IGNORE' did not work for `FEDERATED' tables. (Bug #29019) * Inserting into `InnoDB' tables and executing *Note `RESET MASTER': reset-master. in multiple threads cause assertion failure in debug server binaries. (Bug #28983) * Updates to a `CSV' table could cause a server crash or update the table with incorrect values. (Bug #28971) * For a `ucs2' column, `GROUP_CONCAT()' did not convert separators to the result character set before inserting them, producing a result containing a mixture of two different character sets. (Bug #28925) * Dropping the definer of an active event caused the server to crash. (Bug #28924) * For a join with `GROUP BY' or `ORDER BY' and a view reference in the `FROM' list, the query metadata erroneously showed empty table aliases and database names for the view columns. (Bug #28898) * Creating an event using `ON SCHEDULE AT CURRENT_TIMESTAMP + INTERVAL ...' could in some cases cause *Note `mysqld': mysqld. to crash. (Bug #28881) * Coercion of ASCII values to character sets that are a superset of ASCII sometimes was not done, resulting in `illegal mix of collations' errors. These cases now are resolved using repertoire, a new string expression attribute (see *Note charset-repertoire::). (Bug #28875) * Executing *Note `ALTER EVENT': alter-event. on an event whose definer's event creation privileges had been revoked cause the server to crash. (Bug #28873) * *Note `ALTER VIEW': alter-view. is not supported as a prepared statement but was not being rejected. *Note `ALTER VIEW': alter-view. is now prohibited as a prepared statement or when called within stored routines. (Bug #28846) * In strict SQL mode, errors silently stopped the SQL thread even for errors named using the `--slave-skip-errors' option. (Bug #28839) * Fast *Note `ALTER TABLE': alter-table. (that works without rebuilding the table) acquired duplicate locks in the storage engine. In `MyISAM', if *Note `ALTER TABLE': alter-table. was issued under *Note `LOCK TABLE': lock-tables, it caused all data inserted after *Note `LOCK TABLE': lock-tables. to disappear. (Bug #28838) * Runtime changes to the `log_queries_not_using_indexes' system variable were ignored. (Bug #28808) * Selecting a column not present in the selected-from table caused an extra error to be produced by *Note `SHOW ERRORS': show-errors. (Bug #28677) * Creating an event to be executed at a time close to the end of the permitted range (2038-01-19 03:14:07 UTC) would cause the server to crash. (Bug #28641) * For a statement of the form `CREATE t1 SELECT INTEGER_CONSTANT', the server created the column using the *Note `DECIMAL': numeric-types. data type for large negative values that are within the range of *Note `BIGINT': numeric-types. (Bug #28625) * Starting the server with an `innodb_force_recovery' value of 4 did not work. (Bug #28604) * For `InnoDB' tables, MySQL unnecessarily sorted records in certain cases when the records were retrieved by `InnoDB' in the proper order already. (Bug #28591) * *Note `mysql_install_db': mysql-install-db. could fail to find script files that it needs. (Bug #28585) * If a stored procedure was created and invoked prior to selecting a default database with *Note `USE': use, a `No database selected' error occurred. (Bug #28551) * On Mac OS X, shared-library installation path names were incorrect. (Bug #28544) * Using the `--skip-add-drop-table 'option with *Note `mysqldump': mysqldump. generated incorrect SQL if the database included any views. The recreation of views requires the creation and removal of temporary tables. This option suppressed the removal of those temporary tables. The same applied to `--compact' since this option also invokes `--skip-add-drop-table'. (Bug #28524) * *Note `mysqlbinlog --hexdump': mysqlbinlog. generated incorrect output due to omission of the ``#'' comment character for some comment lines. (Bug #28293) * `InnoDB' could crash if the server was shut down while `innodb_table_monitor' was running. (Bug #28254) * A race condition in the interaction between `MyISAM' and the query cache code caused the query cache not to invalidate itself for concurrently inserted data. (Bug #28249) * A duplicate-key error message could display an incorrect key value when not all columns of the key were used to select rows for update. (Bug #28158) * Indexing column prefixes in `InnoDB' tables could cause table corruption. (Bug #28138) * Index creation could fail due to truncation of key values to the maximum key length rather than to a mulitiple of the maximum character length. (Bug #28125) * Instance Manager had a race condition when it received a shutdown request while a guarded *Note `mysqld': mysqld. instance was starting such that it could fail to stop the *Note `mysqld': mysqld. instance. (Bug #28030) * *Note `SELECT ... FOR UPDATE': select. with partitioned tables could cause a server crash. (Bug #28026) * On Windows, Instance Manager would crash if an instance object failed to initialize during startup. This could happen if an incorrect *Note `mysqld': mysqld. path was supplied in the configuration file. (Bug #28012) * The `LOCATE()' function returned `NULL' if any of its arguments evaluated to `NULL'. Likewise, the predicate, `LOCATE(STR,NULL) IS NULL', erroneously evaluated to `FALSE'. (Bug #27932) * Dropping a user-defined function could cause a server crash if the function was still in use by another thread. (Bug #27564) * For some event-creation problems, the server displayed messages that implied the problems were errors when they were only warnings. (Bug #27406) * Unsafe aliasing in the source caused a client library crash when compiled with `gcc' 4 at high optimization levels. (Bug #27383) * Index-based range reads could fail for comparisons that involved contraction characters (such as `ch' in Czech or `ll' in Spanish). (Bug #27345) * Aggregations in subqueries that refer to outer query columns were not always correctly referenced to the proper outer query. (Bug #27333) * Error returns from the `time()' system call were ignored. (Bug #27198) * Phantom reads could occur under `InnoDB' `SERIALIZABLE' isolation level. (Bug #27197) * The `SUBSTRING()' function returned the entire string instead of an empty string when it was called from a stored procedure and when the length parameter was specified by a variable with the value ``0''. (Bug #27130) * Some functions when used in partitioning expressions could cause *Note `mysqld': mysqld. to crash. (Bug #27084) * The server acquired a global mutex for temporary tables, although such tables are thread-specific. This affected performance by blocking other threads. (Bug #27062) * `FEDERATED' tables had an artificially low maximum of key length. (Bug #26909) * Updates to rows in a partitioned table could update the wrong column. (Bug #26827) * Index creation could corrupt the table definition in the `.frm' file: 1) A table with the maximum number of key segments and maximum length key name would have a corrupted `.frm' file, due to incorrect calculation of the total key length. 2) `MyISAM' would reject a table with the maximum number of keys and the maximum number of key segments in all keys. (It would permit one less than this total maximum.) Now `MyISAM' accepts a table defined with the maximum. (Bug #26642) * The Windows implementation of `pthread_join()' was incorrect and could cause crashes. (Bug #26564) * After the first read of a `TEMPORARY' table, *Note `CHECK TABLE': check-table. could report the table as being corrupt. (Bug #26325) * If an operation had an `InnoDB' table, and two triggers, `AFTER UPDATE' and `AFTER INSERT', competing for different resources (such as two distinct `MyISAM' tables), the triggers were unable to execute concurrently. In addition, *Note `INSERT': insert. and *Note `UPDATE': update. statements for the `InnoDB' table were unable to run concurrently. (Bug #26141) * A number of unsupported constructs--including prohibited constructs, the `UCASE()' function, and nested function calls--were permitted in partitioning expressions. (Bug #26082, Bug #18198, Bug #29308) * *Note `ALTER DATABASE': alter-database. did not require at least one option. (Bug #25859) * The index merge union access algorithm could produce incorrect results with `InnoDB' tables. The problem could also occur for queries that used `DISTINCT'. (Bug #25798) * When using a `FEDERATED' table, the value of `LAST_INSERT_ID()' would not correctly update the C API interface, which would affect the autogenerated ID returned both through the C API and the MySQL protocol, affecting Connectors that used the protocol or C API. (Bug #25714) * The server was blocked from opening other tables while the `FEDERATED' engine was attempting to open a remote table. Now the server does not check the correctness of a `FEDERATED' table at *Note `CREATE TABLE': create-table. time, but waits until the table actually is accessed. (Bug #25679) * Under ActiveState Perl, `mysql-test-run.pl' could kill itself when attempting to kill other processes. (Bug #25657) * Several `InnoDB' assertion failures were corrected. (Bug #25645) * A query with `DISTINCT' in the select list to which the loose-scan optimization for grouping queries was applied returned an incorrect result set when the query was used with the `SQL_BIG_RESULT' option. (Bug #25602) * For a multiple-row insert into a `FEDERATED' table that refers to a remote transactional table, if the insert failed for a row due to constraint failure, the remote table would contain a partial commit (the rows preceding the failed one) instead of rolling back the statement completely. This occurred because the rows were treated as individual inserts. Now `FEDERATED' performs bulk-insert handling such that multiple rows are sent to the remote table in a batch. This provides a performance improvement and enables the remote table to perform statement rollback properly should an error occur. This capability has the following limitations: * The size of the insert cannot exceed the maximum packet size between servers. If the insert exceeds this size, it is broken into multiple packets and the rollback problem can occur. * Bulk-insert handling does not occur for *Note `INSERT ... ON DUPLICATE KEY UPDATE': insert-on-duplicate. (Bug #25513) * The `FEDERATED' storage engine failed silently for *Note `INSERT ... ON DUPLICATE KEY UPDATE': insert-on-duplicate. if a duplicate key violation occurred. `FEDERATED' does not support `ON DUPLICATE KEY UPDATE', so now it correctly returns an `ER_DUP_KEY' error if a duplicate key violation occurs. (Bug #25511) * In a stored function or trigger, when `InnoDB' detected deadlock, it attempted rollback and displayed an incorrect error message (`Explicit or implicit commit is not permitted in stored function or trigger'). Now `InnoDB' returns an error under these conditions and does not attempt rollback. Rollback is handled outside of `InnoDB' above the function/trigger level. (Bug #24989) * Dropping a temporary `InnoDB' table that had been locked with *Note `LOCK TABLES': lock-tables. caused a server crash. (Bug #24918) * On Windows, executables did not include Vista manifests. (Bug #24732) See also Bug #22563. * If MySQL/`InnoDB' crashed very quickly after starting up, it would not force a checkpoint. In this case, `InnoDB' would skip crash recovery at next startup, and the database would become corrupt. Now, if the redo log scan at `InnoDB' startup goes past the last checkpoint, crash recovery is forced. (Bug #23710) * *Note `SHOW INNODB STATUS': show-innodb-status. caused an assertion failure under high load. (Bug #22819) * *Note `SHOW BINLOG EVENTS': show-binlog-events. displayed incorrect values of `End_log_pos' for events associated with transactional storage engines. (Bug #22540) * When determining which transaction to kill after deadlock has been detected, `InnoDB' now adds the number of locks to a transaction's weight, and avoids killing transactions that mave modified nontransactional tables. This should reduce the likelihood of killing long-running transactions containing *Note `SELECT ... FOR UPDATE': select. or `INSERT/REPLACE INTO ... SELECT' statements, and of causing partial updates if the target is a `MyISAM' table. (Bug #21293) * `InnoDB' displayed an incorrect error message when a *Note `CREATE TABLE': create-table. statement exceeded the `InnoDB' maximum permissible row size. (Bug #21101) * Under heavy load with a large query cache, invalidating part of the cache could cause the server to freeze (that is, to be unable to service other operations until the invalidation was complete). (Bug #21074) See also Bug #39253. * On Windows, the server used 10MB of memory for each connection thread, resulting in memory exhaustion. Now each thread uses 1MB. (Bug #20815) * `InnoDB' produced an unnecessary (and harmless) warning: ``InnoDB': Error: trying to declare trx to enter `InnoDB', but `InnoDB': it already is declared'. (Bug #20090) * If a slave timed out while registering with the master to which it was connecting, auto-reconnect failed thereafter. (Bug #19328) * If `InnoDB' reached its limit on the number of concurrent transactions (1023), it wrote a descriptive message to the error log but returned a misleading error message to the client, or an assertion failure occurred. (Bug #18828) See also Bug #46672. * Under ActiveState Perl, `mysql-test-run.pl' would not run. (Bug #18415) * The server crashed when the size of an `ARCHIVE' table grew larger than 2GB. (Bug #15787) * `SQL_BIG_RESULT' had no effect for *Note `CREATE TABLE ... SELECT SQL_BIG_RESULT ...': create-table-select. statements. (Bug #15130) * On 64-bit Windows systems, the Config Wizard failed to complete the setup because 64-bit Windows does not resolve dynamic linking of the 64-bit `libmysql.dll' to a 32-bit application like the Config Wizard. (Bug #14649) * *Note `mysql_setpermission': mysql-setpermission. tried to grant global-only privileges at the database level. (Bug #14618) * For the general query log, logging of prepared statements executed using the C API differed from logging of prepared statements performed with *Note `PREPARE': prepare. and *Note `EXECUTE': execute. Logging for the latter was missing the `Prepare' and `Execute' lines. (Bug #13326) * The `TABLE_COMMENT' column of *Note `INFORMATION_SCHEMA.TABLES': tables-table. and the `Comment' column in the output of *Note `SHOW TABLE STATUS': show-table-status. displayed extraneous information for `InnoDB' and *Note `NDBCLUSTER': mysql-cluster. tables. (Bug #11379) See also Bug #32440. * The server returned data from *Note `SHOW CREATE TABLE': show-create-table. statement or a *Note `SELECT': select. statement on an `INFORMATION_SCHEMA' table using the `binary' character set. (Bug #10491) * Backup software can cause `ERROR_SHARING_VIOLATION' or `ERROR_LOCK_VIOLATION' conditions during file operations. `InnoDB' now retries forever until the condition goes away. (Bug #9709)  File: manual.info, Node: news-5-1-20, Next: news-5-1-19, Prev: news-5-1-21, Up: news-5-1-x D.1.48 Changes in MySQL 5.1.20 (25 June 2007) --------------------------------------------- This is a new Beta development release, fixing recently discovered bugs. *Note*: This Beta release, as any other pre-production release, should not be installed on _production_ level systems or systems with critical data. It is good practice to back up your data before installing any new version of software. Although MySQL has worked very hard to ensure a high level of quality, protect your data by making a backup as you would for any software beta release. Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. This section documents all changes and bug fixes that have been applied since the last official MySQL release. If you would like to receive more fine-grained and personalized _update alerts_ about fixes that are relevant to the version and features you use, please consider subscribing to _MySQL Enterprise_ (a commercial MySQL offering). For more details, please see http://www.mysql.com/products/enterprise. *Functionality added or changed:* * *Incompatible Change*: It is no longer possible to partition the log tables. (Bug #27816) * *Incompatible Change*: *Note `mysqld_safe': mysqld-safe. now supports error logging to `syslog' on systems that support the `logger' command. The new `--syslog' and `--skip-syslog' options can be used instead of the `--log-error' option to control logging behavior, as described in *Note mysqld-safe::. The default is to use `syslog', which differs from the previous default behavior of writing an error log file. *Currently, logging to `syslog' may fail to operate correctly in some cases; if so, use `--skip-syslog' or `--log-error'.* To maintain the older behavior if you were using no error-logging option, use `--skip-syslog'. If you were using `--log-error', continue to use it. Note: In 5.1.21, the default is changed to `--skip-syslog', which is compatible with releases prior to 5.1.20. (Bug #4858) * *Important Change*: *MySQL Cluster*: The `TimeBetweenWatchdogCheckInitial' configuration parameter was added to enable setting of a separate watchdog timeout for memory allocation during startup of the data nodes. (Bug #28899) * *MySQL Cluster*: The cluster management client now stores command history between sessions. (Bug #29073) * *MySQL Cluster*: `auto_increment_increment' and `auto_increment_offset' are now supported for *Note `NDB': mysql-cluster. tables. (Bug #26342) * *MySQL Cluster*: The server source tree now includes scripts to simplify building MySQL with SCI support. For more information about SCI interconnects and these build scripts, see *Note mysql-cluster-sci-sockets::. (Bug #25470) * *MySQL Cluster*: A new configuration parameter `ODirect' causes *Note `NDB': mysql-cluster. to attempt using `O_DIRECT' writes for LCP, backups, and redo logs, often lowering CPU usage. * *Replication*: The `sql_mode', `foreign_key_checks', `unique_checks', character set/collations, and `sql_auto_is_null' session variables are written to the binary log and honored during replication. See *Note binary-log::. * If a `MERGE' table cannot be opened or used because of a problem with an underlying table, *Note `CHECK TABLE': check-table. now displays information about which table caused the problem. (Bug #26976) * User variables and stored procedure variables are now supported for use in XPath expressions employed as arguments to the `ExtractValue()' and `UpdateXML()' functions. This means that: * XPath can now be used to load data from XML files using virtually any format, and so able to import data from most third party software which either has XML export functionality, or uses XML natively as a storage format. * Various complex conditions can be put on rows and columns, so one can filter for desired rows (or skip unwanted rows) when loading XML. * Various types of preprocessing using SQL functions are now possible when loading XML. For example, you can concatenate two XML tag or attribute values into a single column value using `CONCAT()', or remove some parts of the data using `REPLACE()'. See *Note xml-functions::, for more information. (Bug #26518) * Binary distributions for some platforms did not include shared libraries; now shared libraries are shipped for all platforms except AIX 5.2 64-bit. _Exception_: The library for the `libmysqld' embedded server is not shared except on Windows. (Bug #16520, Bug #26767, Bug #13450) * Added a new `PAD_CHAR_TO_FULL_LENGTH' SQL mode. By default, trailing spaces are trimmed from *Note `CHAR': char. column values on retrieval. If `PAD_CHAR_TO_FULL_LENGTH' is enabled, trimming does not occur and retrieved *Note `CHAR': char. values are padded to their full length. This mode does not apply to *Note `VARCHAR': char. columns, for which trailing spaces are retained on retrieval. * XPath can now be used to load data from XML files using virtually any format, and so able to import data from most third party software which either has XML export functionality, or uses XML natively as a storage format. * Various complex conditions can be put on rows and columns, so one can filter for desired rows (or skip unwanted rows) when loading XML. * Various types of preprocessing using SQL functions are now possible when loading XML. For example, you can concatenate two XML tag or attribute values into a single column value using `CONCAT()', or remove some parts of the data using `REPLACE()'. *Bugs fixed:* * *Security Fix*: A malformed password packet in the connection protocol could cause the server to crash. Thanks for Dormando for reporting this bug, and for providing details and a proof of concept. (Bug #28984, CVE-2007-3780) * *Security Fix*: *Note `CREATE TABLE LIKE': create-table. did not require any privileges on the source table. Now it requires the `SELECT' privilege. In addition, *Note `CREATE TABLE LIKE': create-table. was not isolated from alteration by other connections, which resulted in various errors and incorrect binary log order when trying to execute concurrently a *Note `CREATE TABLE LIKE': create-table. statement and either DDL statements on the source table or DML or DDL statements on the target table. (Bug #23667, Bug #25578, CVE-2007-3781) * *Incompatible Change*: Some error codes had error numbers in MySQL 5.1 different from the numbers in MySQL 5.0. In MySQL 5.1, error numbers have been changed to match the MySQL 5.0 values: Error codes with value of 1458 or higher have changed in MySQL 5.1 now. Client applications designed to work with MySQL 5.1 with hard-coded error code values (for example, in statements such as `if (mysql_errno(mysql) == 1463) { ... }') need to be updated in the source code. All clients designed to work with MySQL 5.1 that test error codes (for example, in statements such as `if (mysql_errno(mysql) == ER_VIEW_RECURSIVE) { ... }') should be recompiled. Existing 5.0 clients should now work, without changes or recompilation, against servers for MySQL 5.1.20 or higher. (Bug #29245) * *Incompatible Change*: The names of stored functions referenced by views were not properly displayed by *Note `SHOW CREATE VIEW': show-create-view. The fix corrects a problem introduced by Bug#23491. There is an incompatibility when upgrading from versions affected by that bug fix (MySQL 5.0.40 through 5.0.43, MySQL 5.1.18 through 5.1.19): If you use *Note `mysqldump': mysqldump. before upgrading from an affected version and reload the data after upgrading to a higher version, you must drop and recreate your views. (Bug #28605) * *Incompatible Change*: When *Note `mysqldump': mysqldump. was run with the `--delete-master-logs' option, binary log files were deleted before it was known that the dump had succeeded, not after. (The method for removing log files used *Note `RESET MASTER': reset-master. prior to the dump. This also reset the binary log sequence numbering to `.000001'.) Now *Note `mysqldump': mysqldump. flushes the logs (which creates a new binary log number with the next sequence number), performs the dump, and then uses *Note `PURGE BINARY LOGS': purge-binary-logs. to remove the log files older than the new one. This also preserves log numbering because the new log with the next number is generated and only the preceding logs are removed. However, this may affect applications if they rely on the log numbering sequence being reset. (Bug #24733) * *Incompatible Change*: The use of an `ORDER BY' or `DISTINCT' clause with a query containing a call to the `GROUP_CONCAT()' function caused results from previous queries to be redisplayed in the current result. The fix for this includes replacing a *Note `BLOB': blob. value used internally for sorting with a *Note `VARCHAR': char. This means that for long results (more than 65,535 bytes), it is possible for truncation to occur; if so, an appropriate warning is issued. (Bug #23856, Bug #28273) * *MySQL Cluster*: *Replication*: (Replication): A replicated unique key permitted duplicate key inserts on the slave. (Bug #27044) * *MySQL Cluster*: Memory corruption could occur due to a problem in the `DBTUP' kernel block. (Bug #29229) * *MySQL Cluster*: A query having a large `IN(...)' or `NOT IN(...)' list in the `WHERE' condition on an *Note `NDB': mysql-cluster. table could cause *Note `mysqld': mysqld. to crash. (Bug #29185) * *MySQL Cluster*: In the event that two data nodes in the same node group and participating in a GCP crashed before they had written their respective `P0.sysfile' files, `QMGR' could refuse to start, issuing an invalid `Insufficient nodes for restart' error instead. (Bug #29167) * *MySQL Cluster*: Attempting to restore a `NULL' row to a *Note `VARBINARY': binary-varbinary. column caused *Note `ndb_restore': mysql-cluster-programs-ndb-restore. to fail. (Bug #29103) * *MySQL Cluster*: *Note `ndb_error_reporter': mysql-cluster-programs-ndb-error-reporter. now preserves timestamps on files. (Bug #29074) * *MySQL Cluster*: It is now possible to set the maximum size of the allocation unit for table memory using the `MaxAllocate' configuration parameter. (Bug #29044) * *MySQL Cluster*: When shutting down *Note `mysqld': mysqld, the *Note `NDB': mysql-cluster. binlog process was not shut down before log cleanup began. (Bug #28949) * *MySQL Cluster*: *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. could hang when connecting to a nonexistent host. (Bug #28847) * *MySQL Cluster*: A regression in the heartbeat monitoring code could lead to node failure under high load. This issue affected MySQL 5.1.19 and MySQL Cluster NDB 6.1.10 only. (Bug #28783) * *MySQL Cluster*: A corrupt schema file could cause a `File already open' error. (Bug #28770) * *MySQL Cluster*: Having large amounts of memory locked caused swapping to disk. (Bug #28751) * *MySQL Cluster*: Setting `InitialNoOfOpenFiles' equal to `MaxNoOfOpenFiles' caused an error. This was due to the fact that the actual value of `MaxNoOfOpenFiles' as used by the cluster was offset by 1 from the value set in `config.ini'. (Bug #28749) * *MySQL Cluster*: LCP files were not removed following an initial system restart. (Bug #28726) * *MySQL Cluster*: `UPDATE IGNORE' statements involving the primary keys of multiple tables could result in data corruption. (Bug #28719) * *MySQL Cluster*: A race condition could result when nonmaster nodes (in addition to the master node) tried to update active status due to a local checkpoint (that is, between `NODE_FAILREP' and `COPY_GCIREQ' events). Now only the master updates the active status. (Bug #28717) * *MySQL Cluster*: A fast global checkpoint under high load with high usage of the redo buffer caused data nodes to fail. (Bug #28653) * *MySQL Cluster*: The management client's response to `START BACKUP WAIT COMPLETED' did not include the backup ID. (Bug #27640) * *Cluster Replication*: *Replication*: When replicating `MyISAM' or `InnoDB' tables to a MySQL Cluster, it was not possible to determine exactly what had been applied following a shutdown of the slave cluster or *Note `mysqld': mysqld. process. (Bug #26783) * *Replication*: *Note `DROP USER': drop-user. statements that named multiple users, only some of which could be dropped, were replicated incorrectly. (Bug #29030) * *Replication*: Using events in replication could cause the slave to crash. (Bug #28953) * *Replication*: It was possible to set `SQL_SLAVE_SKIP_COUNTER' such that the slave would jump into the middle of an event group. (Bug #28618) See also Bug #12691. * *Replication*: The result of executing of a prepared statement created with `PREPARE s FROM "SELECT 1 LIMIT ?"' was not replicated correctly. (Bug #28464) * *Replication*: Recreating a view that already exists on the master would cause a replicating slave to terminate replication with a 'different error message on slave and master' error. (Bug #28244) * *Replication*: Binary logging of prepared statements could produce syntactically incorrect queries in the binary log, replacing some parameters with variable names rather than variable values. This could lead to incorrect results on replication slaves. (Bug #26842, Bug #12826) * *Replication*: Connections from one *Note `mysqld': mysqld. server to another failed on Mac OS X, affecting replication and `FEDERATED' tables. (Bug #26664) See also Bug #29083. * *Replication*: When using transactions and replication, shutting down the master in the middle of a transaction would cause all slaves to stop replicating. (Bug #22725) * *Replication*: Using *Note `CREATE TABLE LIKE ...': create-table. would raise an assertion when replicated to a slave. (Bug #18950) * *Disk Data*: When loading data into a cluster following a version upgrade, the data nodes could forcibly shut down due to page and buffer management failures (that is, `ndbrequire' failures in `PGMAN'). (Bug #28525) * *Disk Data*: Repeated *Note `INSERT': insert. and *Note `DELETE': delete. operations on a Disk Data table having one or more large *Note `VARCHAR': char. columns could cause data nodes to fail. (Bug #20612) * *Cluster API*: The timeout set using the MGM API `ndb_mgm_set_timeout()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-set-timeout.html) function was incorrectly interpreted as seconds rather than as milliseconds. (Bug #29063) * *Cluster API*: An invalid error code could be set on transaction objects by *Note `BLOB': blob. handling code. (Bug #28724) * The *Note `TRUNCATE TABLE': truncate-table. statement was handled differently by the server when row-based logging was in effect, even though the binlogging format in effect does not effect the fact that *Note `TRUNCATE TABLE': truncate-table. is always logged as a statement. (Bug #29130) * If one of the queries in a *Note `UNION': union. used the `SQL_CACHE' option and another query in the *Note `UNION': union. contained a nondeterministic function, the result was still cached. For example, this query was incorrectly cached: SELECT NOW() FROM t1 UNION SELECT SQL_CACHE 1 FROM t1; (Bug #29053) * Long path names for internal temporary tables could cause stack overflows. (Bug #29015) * Using an *Note `INTEGER': numeric-types. column from a table to `ROUND()' a number produced different results than using a constant with the same value as the *Note `INTEGER': numeric-types. column. (Bug #28980) * If a program binds a given number of parameters to a prepared statement handle and then somehow changes `stmt->param_count' to a different number, *Note `mysql_stmt_execute()': mysql-stmt-execute. could crash the client or server. (Bug #28934) * Queries using UDFs or stored functions were cached. (Bug #28921) * `INSERT .. ON DUPLICATE KEY UPDATE' could under some circumstances silently update rows when it should not have. (Bug #28904) * Queries that used `UUID()' were incorrectly permitted into the query cache. (This should not happen because `UUID()' is nondeterministic.) (Bug #28897) * Using a `VIEW' created with a nonexisting `DEFINER' could lead to incorrect results under some circumstances. (Bug #28895) * For `InnoDB' tables that use the `utf8' character set, incorrect results could occur for DML statements such as *Note `DELETE': delete. or *Note `UPDATE': update. that use an index on character-based columns. (Bug #28878) See also Bug #29449, Bug #30485, Bug #31395. This regression was introduced by Bug #13195. * Non-`utf8' characters could get mangled when stored in `CSV' tables. (Bug #28862) * On Windows, `USE_TLS' was not defined for `mysqlclient.lib'. (Bug #28860) * In MySQL 5.1.15, a new error code `ER_DUP_ENTRY_WITH_KEY_NAME' (1582) was introduced to replace `ER_DUP_ENTRY' (1062) so that the key name could be provided instead of the key number. This was unnecessary, so `ER_DUP_ENTRY' is used again and the key name is printed. The incompatibility introduced in 5.1.15 no longer applies. (Bug #28842) * A subquery with `ORDER BY' and `LIMIT 1' could cause a server crash. (Bug #28811) * Running *Note `SHOW TABLE STATUS': show-table-status. while performing a high number of inserts on partitioned tables with a great many partitions could cause the server to crash. (Bug #28806) * Using `BETWEEN' with nonindexed date columns and short formats of the date string could return incorrect results. (Bug #28778) * Selecting `GEOMETRY' columns in a *Note `UNION': union. caused a server crash. (Bug #28763) * When constructing the path to the original `.frm' file, `ALTER .. RENAME' was unnecessarily (and incorrectly) lowercasing the entire path when not on a case-insensitive file system, causing the statement to fail. (Bug #28754) * The `binlog_format' system variable value was empty if the server was started with binary logging disabled. Now it is set to `MIXED'. (Bug #28752) * Searches on indexed and nonindexed *Note `ENUM': enum. columns could return different results for empty strings. (Bug #28729) * Executing *Note `EXPLAIN EXTENDED': explain. on a query using a derived table over a grouping subselect could lead to a server crash. This occurred only when materialization of the derived tables required creation of an auxiliary temporary table, an example being when a grouping operation was carried out with usage of a temporary table. (Bug #28728) * The result of evaluation for a view's `CHECK OPTION' option over an updated record and records of merged tables was arbitrary and dependant on the order of records in the merged tables during the execution of the *Note `SELECT': select. statement. (Bug #28716) * The `manager thread' of the LinuxThreads implementation was unintentionally started before *Note `mysqld': mysqld. had dropped privileges (to run as an unprivileged user). This caused signaling between threads in *Note `mysqld': mysqld. to fail when the privileges were finally dropped. (Bug #28690) * Setting an interval of `EVERY 0 SECOND' for a scheduled event caused the server to crash. (Bug #28666) * For debug builds, *Note `ALTER TABLE': alter-table. could trigger an assertion failure due to occurrence of a deadlock when committing changes. (Bug #28652) * Attempting to create an index on a *Note `BIT': numeric-types. column failed after modifying the column. (Bug #28631) * Conversion of U+00A5 YEN SIGN and U+203E OVERLINE from `ucs2' to `ujis' produced incorrect results. (Bug #28600) * Killing from one connection a long-running `EXPLAIN QUERY' started from another connection caused *Note `mysqld': mysqld. to crash. (Bug #28598) * *Note `SHOW GLOBAL VARIABLES': show-variables. repeated some variable names. (Bug #28580) * When one thread attempts to lock two (or more) tables and another thread executes a statement that aborts these locks (such as *Note `REPAIR TABLE': repair-table, *Note `OPTIMIZE TABLE': optimize-table, or *Note `CHECK TABLE': check-table.), the thread might get a table object with an incorrect lock type in the table cache. The result is table corruption or a server crash. (Bug #28574) * Outer join queries with `ON' conditions over constant outer tables did not return `NULL'-complemented rows when conditions were evaluated to `FALSE'. (Bug #28571) * An update on a multiple-table view with the `CHECK OPTION' clause and a subquery in the `WHERE' condition could cause an assertion failure. (Bug #28561) * Calling the `UpdateXML()' function using invalid XPath syntax caused memory corruption possibly leading to a crash of the server. (Bug #28558) * `PURGE MASTER LOGS BEFORE (SUBQUERY)' caused a server crash. Subqueries are forbidden in the `BEFORE' clause now. (Bug #28553) * *Note `mysqldump': mysqldump. calculated the required memory for a hex-blob string incorrectly causing a buffer overrun. This in turn caused *Note `mysqldump': mysqldump. to crash silently and produce incomplete output. (Bug #28522) * When upgrading from MySQL 5.1.17 to 5.1.18, *Note `mysql_upgrade': mysql-upgrade. and *Note `mysql_fix_privilege_tables': mysql-fix-privilege-tables. did not upgrade the system tables relating to the Event Scheduler correctly. (Bug #28521) * Passing a *Note `DECIMAL': numeric-types. value as a parameter of a statement prepared with *Note `PREPARE': prepare. resulted in an error. (Bug #28509) * *Note `mysql_affected_rows()': mysql-affected-rows. could return an incorrect result for *Note `INSERT ... ON DUPLICATE KEY UPDATE': insert-on-duplicate. if the `CLIENT_FOUND_ROWS' flag was set. (Bug #28505) * A query that grouped by the result of an expression returned a different result when the expression was assigned to a user variable. (Bug #28494) * Subselects returning `LONG' values in MySQL versions later than 5.0.24a returned `LONGLONG' prior to this. The previous behavior was restored. (Bug #28492) This regression was introduced by Bug #19714. * Performing `ALTER TABLE ... ADD PARTITION' or `ALTER TABLE DROP PARTITION' could result in inconsistent data, or cause the server to crash, if done concurrently with other accesses to the table. (Bug #28477, Bug #28488) * Forcing the use of an index on a *Note `SELECT': select. query when the index had been disabled would raise an error without running the query. The query now executes, with a warning generated noting that the use of a disabled index has been ignored. (Bug #28476) * The query `SELECT '2007-01-01' + INTERVAL COLUMN_NAME DAY FROM TABLE_NAME' caused *Note `mysqld': mysqld. to fail. (Bug #28450) * A server crash could happen under rare conditions such that a temporary table outgrew heap memory reserved for it and the remaining disk space was not big enough to store the table as a `MyISAM' table. (Bug #28449) * Using *Note `ALTER TABLE': alter-table. to move columns resulted only in the columns being renamed. The table contents were not changed. (Bug #28427) * The test case for *Note `mysqldump': mysqldump. failed with `bin-log' disabled. (Bug #28372) * Attempting to `LOAD_FILE' from an empty floppy drive under Windows, caused the server to hang. For example, if you opened a connection to the server and then issued the command `SELECT LOAD_FILE('a:test');', with no floppy in the drive, the server was inaccessible until the modal pop-up dialog box was dismissed. (Bug #28366) * `mysqltest' used a too-large stack size on PowerPC/Debian Linux, causing thread-creation failure for tests that use many threads. (Bug #28333) * When using a `MEMORY' table on Mac OS X, dropping a table and than creating a table with the same name could cause the information of the deleted table to remain accessible, leading to index errors. (Bug #28309) * The `IS_UPDATABLE' column in the *Note `INFORMATION_SCHEMA.VIEWS': views-table. table was not always set correctly. (Bug #28266) * For `CAST()' of a `NULL' value with type *Note `DECIMAL': numeric-types, the return value was incorrectly initialized, producing a runtime error for binaries built using Visual C++ 2005. (Bug #28250) * When the query cache was fully used, issuing `RENAME DATABASE' or `RENAME SCHEMA' could cause the server to hang, with 100% CPU usage. (Bug #28211) * The `Bytes_received' and `Bytes_sent' status variables could hold only 32-bit values (not 64-bit values) on some platforms. (Bug #28149) * Some valid identifiers were not parsed correctly. (Bug #28127) * Storing a large number into a *Note `FLOAT': numeric-types. or *Note `DOUBLE': numeric-types. column with a fixed length could result in incorrect truncation of the number if the column's length was greater than 31. (Bug #28121) * Sending debugging information from a dump of the Event Scheduler to `COM_DEBUG' could cause the server to crash. (Bug #28075) * The `PARTITION_COMMENT' column of the *Note `INFORMATION_SCHEMA.PARTITIONS': partitions-table. table had the wrong default value. (Bug #28007) * *Note `DECIMAL': numeric-types. values beginning with nine `9' digits could be incorrectly rounded. (Bug #27984) * For attempts to open a nonexistent table, the server should report `ER_NO_SUCH_TABLE' but sometimes reported `ER_TABLE_NOT_LOCKED'. (Bug #27907) * Following an invalid call to `UpdateXML()', calling the function again (even if valid) crashed the server. (Bug #27898) * A stored program that uses a variable name containing multibyte characters could fail to execute. (Bug #27876) * The server made strong assumptions about the structure of the `general_log' and `slow_log' log tables: It supported only the table structure defined in the `mysql' database creation scripts. The server also permitted limited *Note `ALTER TABLE': alter-table. operations on the log tables, but adding an `AUTO_INCREMENT' column did not properly initialize the column, and subsequent inserts into the table could fail to generate correct sequence numbers. Now an *Note `ALTER TABLE': alter-table. statement that adds an `AUTO_INCREMENT' column populates the column correctly. In addition, when the server writes a log table row, it will set columns not present in the original table structure to their default values. (Bug #27857) * `ON' conditions from `JOIN' expressions were ignored when checking the `CHECK OPTION' clause while updating a multiple-table view that included such a clause. (Bug #27827) * On some systems, `udf_example.c' returned an incorrect result length. Also on some systems, `mysql-test-run.pl' could not find the shared object built from `udf_example.c'. (Bug #27741) * The modification of a table by a partially completed multi-column update was not recorded in the binlog, rather than being marked by an event and a corresponding error code. (Bug #27716) * *Note `SHOW ENGINES': show-engines. and queries on *Note `INFORMATION_SCHEMA.ENGINES': engines-table. did not use the same values for representing the same storage engine states. (Bug #27684) * `HASH' indexes on *Note `VARCHAR': char. columns with binary collations did not ignore trailing spaces from strings before comparisons. This could result in duplicate records being successfully inserted into a `MEMORY' table with unique key constraints. A consequence was that internal `MEMORY' tables used for `GROUP BY' calculation contained duplicate rows that resulted in duplicate-key errors when converting those temporary tables to `MyISAM', and that error was incorrectly reported as a `table is full' error. (Bug #27643) * An error occurred trying to connect to *Note `mysqld-debug.exe': mysqld. (Bug #27597) * A stack overrun could occur when storing *Note `DATETIME': datetime. values using repeated prepared statements. (Bug #27592) * If a stored function or trigger was killed, it aborted but no error was thrown, permitting the calling statement to continue without noticing the problem. This could lead to incorrect results. (Bug #27563) * When *Note `ALTER TABLE': alter-table. was used to add a new *Note `DATE': datetime. column with no explicit default value, `'0000-00-00'' was used as the default even if the SQL mode included the `NO_ZERO_DATE' mode to prohibit that value. A similar problem occurred for *Note `DATETIME': datetime. columns. (Bug #27507) * `ALTER TABLE ... ENABLE KEYS' could cause *Note `mysqld': mysqld. to crash when executed on a table containing on a `MyISAM' table containing billions of rows. (Bug #27029) * Binary content `0x00' in a *Note `BLOB': blob. column sometimes became `0x5C 0x00' following a dump and reload, which could cause problems with data using multi-byte character sets such as `GBK' (Chinese). This was due to a problem with `SELECT INTO OUTFILE' whereby *Note `LOAD DATA': load-data. later incorrectly interpreted `0x5C' as the second byte of a multi-byte sequence rather than as the `SOLIDUS' (`\') character, used by MySQL as the escape character. (Bug #26711) * The server crashed when attempting to open a table having a `#mysql50#' prefix in the database or table name. The server now will not open such tables. (This prefix is reserved by *Note `mysql_upgrade': mysql-upgrade. for accessing 5.0 tables that have names not yet encoded for 5.1.) (Bug #26402) * A *Note `FLUSH TABLES WITH READ LOCK': flush. statement followed by a *Note `FLUSH LOGS': flush. statement caused a deadlock if the general log or the slow query log was enabled. (Bug #26380) * The query `SELECT /*2*/ user, host, db, info FROM INFORMATION_SCHEMA.PROCESSLIST WHERE (command!='Daemon' || user='event_scheduler') AND (info IS NULL OR info NOT LIKE '%processlist%') ORDER BY INFO' yielded inconsistent results. (Bug #26338) * For a given user variable `@v', the statements `SELECT @v' and *Note `CREATE TABLE ... AS SELECT @v': create-table-select. did not return the same data type. (Bug #26277) * Statements within triggers ignored the value of the `low_priority_updates' system variable. (Bug #26162) See also Bug #29963. * The embedded server library displayed error messages at startup if the `mysql.plugin' table was not present. This no longer occurs. (Bug #25800) * On Windows, an application that called *Note `mysql_thread_init()': mysql-thread-init. but forgot to call *Note `mysql_thread_end()': mysql-thread-end. would get this error: `Error in my_thread_global_end()'. (Bug #25621) * Embedded `/* ... */' comments were handled incorrectly within the definitions of stored programs and views, resulting in malformed definitions (the trailing `*/' was stripped). This also affected binary log contents. (Bug #25411, Bug #26302) * Due to a race condition, executing *Note `FLUSH PRIVILEGES': flush. in one thread could cause brief table unavailability in other threads. (Bug #24988) * In *Note `SHOW SLAVE STATUS': show-slave-status. output, `Last_Errno' and `Last_Error' were not set after `master_retry_count' errors had occurred. To provide additional information, the statement now displays four additional columns: * `Last_IO_Errno': The number of the last error that caused the I/O thread to stop * `Last_IO_Error': A description of the last error that caused the I/O thread to stop * `Last_SQL_Errno': The number of the last error that caused the SQL thread to stop * `Last_SQL_Error': A description of the last error that caused the SQL thread to stop Also, `Last_Errno' and `Last_Error' now are aliases for `Last_SQL_Errno' and `Last_SQL_Error'. (Bug #24954) * A too-long `shared-memory-base-name' value could cause a buffer overflow and crash the server or clients. (Bug #24924) * When *Note `mysqld': mysqld. was run as a Windows service, shared memory objects were not created in the global namespace and could not be used by clients to connect. (Bug #24731) * On some Linux distributions where LinuxThreads and NPTL `glibc' versions both are available, statically built binaries can crash because the linker defaults to LinuxThreads when linking statically, but calls to external libraries (such as `libnss') are resolved to NPTL versions. This cannot be worked around in the code, so instead if a crash occurs on such a binary/OS combination, print an error message that provides advice about how to fix the problem. (Bug #24611) * A number of *Note `SHOW': show. statements caused *Note `mysqld': mysqld. to crash on recent versions of Solaris. This issue is believed to be present only in MySQL 5.1.12 and later. (Bug #23810) * The server deducted some bytes from the `key_cache_block_size' option value and reduced it to the next lower 512 byte boundary. The resulting block size was not a power of two. Setting the `key_cache_block_size' system variable to a value that is not a power of two resulted in `MyISAM' table corruption. (Bug #23068, Bug #28478, Bug #25853) * Conversion errors could occur when constructing the condition for an `IN' predicate. The predicate was treated as if the affected column contains `NULL', but if the `IN' predicate is inside `NOT', incorrect results could be returned. (Bug #22855) * Linux binaries were unable to dump core after executing a `setuid()' call. (Bug #21723) * Stack overflow caused server crashes. (Bug #21476) * The server was ignoring the return value of the `parse()' function for full-text parser plugins. (Bug #18839) * Granting access privileges to an individual table where the database or table name contained an underscore would fail. (Bug #18660) * The `-lmtmalloc' library was removed from the output of *Note `mysql_config': mysql-config. on Solaris, as it caused problems when building `DBD::mysql' (and possibly other applications) on that platform that tried to use `dlopen()' to access the client library. (Bug #18322) * The `check-cpu' script failed to detect AMD64 Turion processors correctly. (Bug #17707) * When using *Note `mysqlbinlog': mysqlbinlog. with `--read-from-remote-server' to load the data direct from a remote MySQL server would cause a core dump when dumping certain binary log events. (Bug #17654) * Trying to shut down the server following a failed *Note `LOAD DATA INFILE': load-data. caused *Note `mysqld': mysqld. to crash. (Bug #17233) * The omission of leading zeros in dates could lead to erroneous results when these were compared with the output of certain date and time functions. (Bug #16377) * Using up-arrow for command-line recall in *Note `mysql': mysql. could cause a segmentation fault. (Bug #10218) * The result for `CAST()' when casting a value to `UNSIGNED' was limited to the maximum signed *Note `BIGINT': numeric-types. value (9223372036854775808), rather than the maximum unsigned value (18446744073709551615). (Bug #8663) * The internal functions for table preparation, creation, and alteration were not re-execution friendly, causing problems in code that: repeatedly altered a table; repeatedly created and dropped a table; opened and closed a cursor on a table, altered the table, and then reopened the cursor; used *Note `ALTER TABLE': alter-table. to change a table's current `AUTO_INCREMENT' value; created indexes on `utf8' columns. Re-execution of *Note `CREATE DATABASE': create-database, *Note `CREATE TABLE': create-table, and *Note `ALTER TABLE': alter-table. statements in stored routines or as prepared statements also caused incorrect results or crashes. (Bug #4968, Bug #6895, Bug #19182, Bug #19733, Bug #22060, Bug #24879)  File: manual.info, Node: news-5-1-19, Next: news-5-1-18, Prev: news-5-1-20, Up: news-5-1-x D.1.49 Changes in MySQL 5.1.19 (25 May 2007) -------------------------------------------- This is a new Beta development release, fixing recently discovered bugs. *Note*: This Beta release, as any other pre-production release, should not be installed on _production_ level systems or systems with critical data. It is good practice to back up your data before installing any new version of software. Although MySQL has worked very hard to ensure a high level of quality, protect your data by making a backup as you would for any software beta release. Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. This section documents all changes and bug fixes that have been applied since the last official MySQL release. If you would like to receive more fine-grained and personalized _update alerts_ about fixes that are relevant to the version and features you use, please consider subscribing to _MySQL Enterprise_ (a commercial MySQL offering). For more details, please see http://www.mysql.com/products/enterprise. *Functionality added or changed:* * *Incompatible Change*: *Note `INSERT DELAYED': insert-delayed. is now downgraded to a normal *Note `INSERT': insert. if the statement uses functions that access tables or triggers, or that is called from a function or a trigger. This was done to resolve the following interrelated issues: * The server could abort or deadlock for *Note `INSERT DELAYED': insert-delayed. statements for which another insert was performed implicitly (for example, using a stored function that inserted a row). * A trigger using an *Note `INSERT DELAYED': insert-delayed. caused the error `INSERT DELAYED can't be used with table ... because it is locked with LOCK TABLES' although the target table was not actually locked. * *Note `INSERT DELAYED': insert-delayed. into a table with a `BEFORE INSERT' or `AFTER INSERT' trigger gave an incorrect `NEW' pseudocolumn value and caused the server to deadlock or abort. (Bug #21483) See also Bug #20497, Bug #21714. * *MySQL Cluster*: Formerly, restoring a cluster backup made on a MySQL 5.0 Cluster to a 5.1 cluster using a 5.1 version of *Note `ndb_restore': mysql-cluster-programs-ndb-restore. did not resize *Note `VARCHAR': char. columns as might be expected; now, the default behavior of *Note `ndb_restore': mysql-cluster-programs-ndb-restore. in such cases is to resize the *Note `VARCHAR': char. columns. This changed default behavior can be overridden using the `--no-upgrade' (or `-u') option when invoking *Note `ndb_restore': mysql-cluster-programs-ndb-restore. (Bug #22240) * The `BLACKHOLE' storage engine now supports *Note `INSERT DELAYED': insert-delayed. Previously, *Note `INSERT DELAYED': insert-delayed. statements for `BLACKHOLE' tables were not supported, and caused the server to crash. (Bug #27998) * A new status variable, `Com_call_procedure', indicates the number of calls to stored procedures. (Bug #27994) * The `BLACKHOLE' storage engine now supports *Note `LOCK TABLES': lock-tables. and *Note `UNLOCK TABLES': lock-tables. (Bug #26241) * *Note `GLOBAL_STATUS': status-table. * *Note `GLOBAL_VARIABLES': variables-table. * *Note `SESSION_VARIABLES': variables-table. * The data type used for the `VARIABLE_VALUE' column of the following `INFORMATION_SCHEMA' tables has been changed to *Note `VARCHAR': char.: * *Note `GLOBAL_STATUS': status-table. * *Note `SESSION_STATUS': status-table. * *Note `GLOBAL_VARIABLES': variables-table. * *Note `SESSION_VARIABLES': variables-table. For more information, see *Note status-table::, and *Note variables-table::. See also Bug #26994. * *Note `SESSION_STATUS': status-table. *Bugs fixed:* * *Security Fix*: UDFs are supposed to be loadable only from the plugin directory, but this restriction was not being enforced. (Bug #28341) * *Security Fix*: Use of a view could enable a user to gain update privileges for tables in other databases. (Bug #27878, CVE-2007-3782) * *MySQL Cluster*: When an API node sent more than 1024 signals in a single batch, *Note `NDB': mysql-cluster. would process only the first 1024 of these, and then hang. (Bug #28443) * *MySQL Cluster*: A delay in obtaining `AUTO_INCREMENT' IDs could lead to excess temporary errors. (Bug #28410) * *MySQL Cluster*: Local checkpoint files relating to dropped *Note `NDB': mysql-cluster. tables were not removed. (Bug #28348) * *MySQL Cluster*: Multiple operations involving deletes followed by reads were not handled correctly. *Note*: This issue could also affect MySQL Cluster Replication. (Bug #28276) * *MySQL Cluster*: Repeated insertion of data generated by *Note `mysqldump': mysqldump. into *Note `NDB': mysql-cluster. tables could eventually lead to failure of the cluster. (Bug #27437) * *MySQL Cluster*: Restarting a data node caused SQL nodes to log repeatedly and unnecessarily the status of the event buffer, causing a memory leak of approximately 4 MB for each *Note `mysqld': mysqld. process each time this occurred. (This issue was known to occur in MySQL 5.1.16 and later only.) (Bug #27292) * *MySQL Cluster*: *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. failed silently when the cluster configuration file contained invalid `[tcp]' entries. (Bug #27207) * *MySQL Cluster*: `ndb_connectstring' did not appear in the output of *Note `SHOW VARIABLES': show-variables. (Bug #26675) * *MySQL Cluster*: A failure to release internal resources following an error could lead to problems with single user mode. (Bug #25818) * *MySQL Cluster*: DDL operations were not supported on a partially started cluster. (Bug #24631) * *Disk Data*: Extremely large inserts into Disk Data tables could lead to data node failure in some circumstances. (Bug #27942) * *Cluster API*: In a multi-operation transaction, a delete operation followed by the insertion of an implicit `NULL' failed to overwrite an existing value. (Bug #20535) * Some *Note `ALTER TABLE': alter-table. statements that worked in MySQL 5.0 did not work in 5.1. (Bug #28415) * *Note `mysql_upgrade': mysql-upgrade. failed if certain SQL modes were set. Now it sets the mode itself to avoid this problem. (Bug #28401) * A query with a `NOT IN' subquery predicate could cause a crash when the left operand of the predicate evaluated to `NULL'. (Bug #28375) * A buffer overflow could occur when using *Note `DECIMAL': numeric-types. columns on Windows operating systems. (Bug #28361) * `libmysql.dll' could not be dynamically loaded on Windows. (Bug #28358) * Grouping queries with correlated subqueries in `WHERE' conditions could produce incorrect results. (Bug #28337) * *Note `EXPLAIN': explain. for a query on an empty table immediately after its creation could result in a server crash. (Bug #28272) * Comparing a *Note `DATETIME': datetime. column value with a user variable yielded incorrect results. (Bug #28261) * Portability problems caused by use of `isinf()' were corrected. (Bug #28240) * When dumping procedures, *Note `mysqldump `--compact' ': mysqldump. generated output that restored the session variable `sql_mode' without first capturing it. When dumping routines, *Note `mysqldump `--compact' ': mysqldump. neither set nor retrieved the value of `sql_mode'. (Bug #28223) * Comparison of the string value of a date showed as unequal to `CURTIME()'. Similar behavior was exhibited for *Note `DATETIME': datetime. values. (Bug #28208) * For `InnoDB', in some rare cases the optimizer preferred a more expensive `ref' access to a less expensive range access. (Bug #28189) * Comparisons of *Note `DATE': datetime. or *Note `DATETIME': datetime. values for the `IN()' function could yield incorrect results. (Bug #28133) * It was not possible to use the value `-9223372036854775808' (that is, `-MAXVALUE + 1') when specifying a `LIST' partition. (Bug #28005) * The server could hang for `INSERT IGNORE ... ON DUPLICATE KEY UPDATE' if an update failed. (Bug #28000) * `CAST()' to *Note `DECIMAL': numeric-types. did not check for overflow. (Bug #27957) * The second execution of a prepared statement from a *Note `UNION': union. query with `ORDER BY RAND()' caused the server to crash. This problem could also occur when invoking a stored procedure containing such a query. (Bug #27937) * Views ignored precision for `CAST()' operations. (Bug #27921) * Changes to some system variables should invalidate statements in the query cache, but invalidation did not happen. (Bug #27792) * *Note `LOAD DATA': load-data. did not use `CURRENT_TIMESTAMP' as the default value for a *Note `TIMESTAMP': datetime. column for which no value was provided. (Bug #27670) * Selecting `MIN()' on an indexed column that contained only `NULL' values caused `NULL' to be returned for other result columns. (Bug #27573) * Using a *Note `TEXT': blob. local variable in a stored routine in an expression such as `SET VAR = SUBSTRING(VAR, 3)' produced an incorrect result. (Bug #27415) * The error message for error number `137' did not report which database/table combination reported the problem. (Bug #27173) * A large filesort could result in a division by zero error and a server crash. (Bug #27119) * Some `InnoDB' variables were missing from the output of *Note `mysqld --verbose --help': mysqld. (Bug #26987) * Flow control optimization in stored routines could cause exception handlers to never return or execute incorrect logic. (Bug #26977) * Some test suite files were missing from some MySQL-test packages. (Bug #26609) * Running *Note `CHECK TABLE': check-table. concurrently with a *Note `SELECT': select, *Note `INSERT': insert. or other statement on Windows could corrupt a MyISAM table. (Bug #25712) * Concurrent execution of *Note `CREATE TABLE ... SELECT': create-table. and other statements involving the target table suffered from various race conditions, some of which might have led to deadlocks. (Bug #24738) * An attempt to execute *Note `CREATE TABLE ... SELECT': create-table. when a temporary table with the same name already existed led to the insertion of data into the temporary table and creation of an empty nontemporary table. (Bug #24508) * A statement of the form *Note `CREATE TABLE IF NOT EXISTS t1 SELECT f1() AS i': create-table-select. failed with a deadlock error if the stored function `f1()' referred to a table with the same name as the to-be-created table. Now it correctly produces a message that the table already exists. (Bug #22427) * Quoted labels in stored routines were mishandled, rendering the routines unusable. (Bug #21513) * `CURDATE()' is less than `NOW()', either when comparing `CURDATE()' directly (`CURDATE() < NOW()' is true) or when casting `CURDATE()' to *Note `DATE': datetime. (`CAST(CURDATE() AS DATE) < NOW()' is true). However, storing `CURDATE()' in a *Note `DATE': datetime. column and comparing `COL_NAME < NOW()' incorrectly yielded false. This is fixed by comparing a *Note `DATE': datetime. column as *Note `DATETIME': datetime. for comparisons to a *Note `DATETIME': datetime. constant. (Bug #21103) * *Note `CREATE TABLE IF NOT EXISTS ... SELECT': create-table-select. caused a server crash if the target table already existed and had a `BEFORE INSERT' trigger. (Bug #20903) * Deadlock occurred for attempts to execute *Note `CREATE TABLE IF NOT EXISTS ... SELECT': create-table-select. when *Note `LOCK TABLES': lock-tables. had been used to acquire a read lock on the target table. (Bug #20662, Bug #15522) * For dates with 4-digit year parts less than 200, an incorrect implicit conversion to add a century was applied for date arithmetic performed with `DATE_ADD()', `DATE_SUB()', `+ INTERVAL', and `- INTERVAL'. (For example, `DATE_ADD('0050-01-01 00:00:00', INTERVAL 0 SECOND)' became `'2050-01-01 00:00:00''.) (Bug #18997) * Changing the size of a key buffer that is under heavy use could cause a server crash. The fix partially removes the limitation that *Note `LOAD INDEX INTO CACHE': load-index. fails unless all indexes in a table have the same block size. Now the statement fails only if `IGNORE LEAVES' is specified. (Bug #17332)  File: manual.info, Node: news-5-1-18, Next: news-5-1-17, Prev: news-5-1-19, Up: news-5-1-x D.1.50 Changes in MySQL 5.1.18 (08 May 2007) -------------------------------------------- This is a new Beta development release, fixing recently discovered bugs. *Note*: This Beta release, as any other pre-production release, should not be installed on _production_ level systems or systems with critical data. It is good practice to back up your data before installing any new version of software. Although MySQL has worked very hard to ensure a high level of quality, protect your data by making a backup as you would for any software beta release. Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. This section documents all changes and bug fixes that have been applied since the last official MySQL release. If you would like to receive more fine-grained and personalized _update alerts_ about fixes that are relevant to the version and features you use, please consider subscribing to _MySQL Enterprise_ (a commercial MySQL offering). For more details, please see http://www.mysql.com/products/enterprise. *Functionality added or changed:* * *Incompatible Change*: *MySQL Cluster*: The internal specifications for columns in *Note `NDB': mysql-cluster. tables has changed to enable compatibility with future MySQL Cluster releases that are expected to permit online adding and dropping of columns. This change is not backward compatible with earlier versions of MySQL Cluster. See *Note mysql-cluster-upgrade-downgrade-compatibility-online-add-drop-column::, for important information prior to upgrading a MySQL Cluster to MySQL 5.1.18 or later from MySQL 5.1.17 or earlier. See also Bug #28205. * *Incompatible Change*: *Replication*: The *Note `INFORMATION_SCHEMA.EVENTS': events-table. and `mysql.event' tables have been changed to facilitate replication of events. When upgrading to MySQL 5.1.18, you must run *Note `mysql_upgrade': mysql-upgrade. prior to working with events. Until you have done so, any statement relating to the Event Scheduler or these tables (including *Note `SHOW EVENTS': show-events.) will fail with the errors `Expected field status at position 12 to have type enum ('ENABLED','SLAVESIDE_DISABLED','DISABLED'), found enum('ENABLED','DISABLED')' and `Table mysql.event is damaged. Can not open'. These changes were made as part of fixes for the following bugs: * The effects of scheduled events were not replicated (that is, binary logging of scheduled events did not work). * Effects of scheduled events on a replication master were both replicated and executed on the slave, causing double execution of events. * *Note `CREATE FUNCTION': create-function. statements and their effects were not replicated correctly. For more information, see *Note replication-features-invoked::. (Bug #17857, Bug #16421, Bug #20384, Bug #17671) * *Cluster Replication*: *Incompatible Change*: The definition of the `mysql.ndb_apply_status' table has changed such that an online upgrade is not possible from MySQL 5.1.17 or earlier for a replication slave cluster; you must shut down all SQL nodes as part of the upgrade procedure. See *Note mysql-cluster-upgrade-downgrade::, before upgrading. For more information about the changes to `mysql.ndb_apply_status' see *Note mysql-cluster-replication-schema::. * *Incompatible Change*: Prior to this release, when *Note `DATE': datetime. values were compared with *Note `DATETIME': datetime. values, the time portion of the *Note `DATETIME': datetime. value was ignored, or the comparison could be performed as a string compare. Now a *Note `DATE': datetime. value is coerced to the *Note `DATETIME': datetime. type by adding the time portion as `00:00:00'. To mimic the old behavior, use the `CAST()' function as shown in this example: `SELECT DATE_COL = CAST(NOW() AS DATE) FROM TABLE;'. (Bug #28929) * *Incompatible Change*: The plugin interface and its handling of system variables was changed. Command-line options such as `--skip-innodb' now cause an error if `InnoDB' is not built-in or plugin-loaded. You should use `--loose-skip-innodb' if you do not want any error even if `InnoDB' is not available. The `--loose' prefix modifier should be used for all command-line options where you are uncertain whether the plugin exists and when you want the operation to proceed even if the option is necessarily ignored due to the absence of the plugin. (For a description of how `--loose' works, see *Note command-line-options::.) * *Important Change*: When upgrading to MySQL 5.1.18 or later from a previous MySQL version and scheduled events have been used, the upgrade utilities do not accommodate changes in event-related system tables. As a workaround, you can dump events before the upgrade, then restore them from the dump afterward. This issue was fixed in MySQL 5.1.20. See also Bug #28521. * *MySQL Cluster*: The behavior of the *Note `ndb_restore': mysql-cluster-programs-ndb-restore. utility has been changed as follows: * It is now possible to restore selected databases or tables using *Note `ndb_restore': mysql-cluster-programs-ndb-restore. * Several options have been added for use with *Note `ndb_restore': mysql-cluster-programs-ndb-restore. `--print_data' to facilitate the creation of structured data dump files. These options can be used to make dumps made using *Note `ndb_restore': mysql-cluster-programs-ndb-restore. more like those produced by *Note `mysqldump': mysqldump. For details of these changes, see *Note mysql-cluster-programs-ndb-restore::. (Bug #26899, Bug #26900) * *MySQL Cluster*: The following changes were made in the *Note `ndb_size.pl': mysql-cluster-programs-ndb-size-pl. utility: * When *Note `ndb_size.pl': mysql-cluster-programs-ndb-size-pl. calculates a value for a given configuration parameter that is less than the default value, it now suggests the default value instead. * The dependency on `HTML::Template' was removed, with the result that the file `ndb_size.tmpl' is no longer needed or included. (Bug #24227, Bug #24228) * *Cluster Replication*: *Replication*: Some circular replication setups are now supported for MySQL Cluster. See *Note mysql-cluster-replication-issues::, for detailed information. (Bug #17095, Bug #25688) * *Cluster API*: The MGM API now supports explicit setting of network timeouts using the `ndb_mgm_set_timeout()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-set-timeout.html) function. A utility function `ndb_mgm_number_of_mgmd_in_connect_string()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-number-of-mgmd-in-connect-string.html) is also implemented to facilitate calculation of timeouts based on the number of management servers in the cluster. * *Note `mysqld_multi': mysqld-multi. now understands the `--no-defaults', `--defaults-file', and `--defaults-extra-file' options. The `--config-file' option is deprecated; if given, it is treated like `--defaults-extra-file'. (Bug #27390) * If a set function S with an outer reference ` S(OUTER_REF)' cannot be aggregated in the outer query against which the outer reference has been resolved, MySQL interprets ` S(OUTER_REF)' the same way that it would interpret ` S(CONST)'. However, standard SQL requires throwing an error in this situation. An error now is thrown for such queries if the `ANSI' SQL mode is enabled. (Bug #27348) * Several additional data types are supported for columns in `INFORMATION_SCHEMA' tables: *Note `DATE': datetime, *Note `TIME': time, *Note `BLOB': blob, *Note `FLOAT': numeric-types, and all integer types. (Bug #27047) * The output of *Note `mysql': mysql. `--xml' and *Note `mysqldump': mysqldump. `--xml' now includes a valid XML namespace. (Bug #25946) * If you use SSL for a client connection, you can tell the client not to authenticate the server certificate by specifying neither `--ssl-ca' nor `--ssl-capath'. The server still verifies the client according to any applicable requirements established using *Note `GRANT': grant. statements for the client, and it still uses any `--ssl-ca'/`--ssl-capath' values that were passed to server at startup time. (Bug #25309) * Added a `MASTER_SSL_VERIFY_SERVER_CERT' option for the *Note `CHANGE MASTER TO': change-master-to. statement, and a `Master_SSL_Verify_Server_Cert' output column to the *Note `SHOW SLAVE STATUS': show-slave-status. statement. The option value also is written to the `master.info' file. (Bug #19991) * The `innodb_log_archive' system variable has been removed. The impact of this change should be low because the variable was unused, anyway. * Added the `--auto-generate-sql-add-autoincrement', `--auto-generate-sql-execute-number', `--auto-generate-sql-guid-primary', `--auto-generate-sql-secondary-indexes', `--auto-generate-sql-unique-query-number', `--auto-generate-sql-unique-write-number', `--post-query', and `--pre-query', options for *Note `mysqlslap': mysqlslap. Removed the `--lock-directory', `--slave', and `--use-threads' options. * Added `--write-binlog' option for *Note `mysqlcheck': mysqlcheck. This option is enabled by default, but can be given as `--skip-write-binlog' to cause *Note `ANALYZE TABLE': analyze-table, *Note `OPTIMIZE TABLE': optimize-table, and *Note `REPAIR TABLE': repair-table. statements generated by *Note `mysqlcheck': mysqlcheck. not to be written to the binary log. (Bug#26262) * New command-line options: To alleviate ambiguities in variable names, all variables related to plugins can be specified using a `plugin' part in the name. For example, every time where we used to have `innodb' in the command-line options, you can now write `plugin-innodb': --skip-plugin-innodb --plugin-innodb-buffer-pool-size=# Furthermore, this is the preferred syntax. It helps to avoid ambiguities when a plugin, say, `wait', has an option called `timeout'. `--wait-timeout' will still set a system variable, but `--plugin-wait-timeout' will set the plugin variable. Also, there is a new command-line option `--plugin-load' to install or load plugins at initialization time without using the `mysql.plugin' table. * Storage engine plugins may now be uninstalled at run time. However, a plugin is not actually uninstalled until after its reference count drops to zero. The `default_storage_engine' system variable consumes a reference count, so uninstalling will not complete until said reference is removed. * The `mysql_create_system_tables' script was removed because *Note `mysql_install_db': mysql-install-db. no longer uses it in MySQL 5.1. * Renamed the `old_mode' system variable to `old'. *Bugs fixed:* * *Security Fix*: The requirement of the `DROP' privilege for *Note `RENAME TABLE': rename-table. was not enforced. (Bug #27515, CVE-2007-2691) * *Security Fix*: If a stored routine was declared using `SQL SECURITY INVOKER', a user who invoked the routine could gain privileges. (Bug #27337, CVE-2007-2692) * *Security Fix*: A user with only the `ALTER' privilege on a partitioned table could obtain information about the table that should require the `SELECT' privilege. (Bug #23675, CVE-2007-2693) * *MySQL Cluster*: *Replication*: (Replication): An *Note `UPDATE': update. on the master became a *Note `DELETE': delete. on slaves. (Bug #27378) * *MySQL Cluster*: The cluster waited 30 seconds instead of 30 milliseconds before reading table statistics. (Bug #28093) * *MySQL Cluster*: Under certain rare circumstances, *Note `ndbd': mysql-cluster-programs-ndbd. could get caught in an infinite loop when one transaction took a read lock and then a second transaction attempted to obtain a write lock on the same tuple in the lock queue. (Bug #28073) * *MySQL Cluster*: Under some circumstances, a node restart could fail to update the Global Checkpoint Index (GCI). (Bug #28023) * *MySQL Cluster*: *Note `INSERT IGNORE': insert. wrongly ignored `NULL' values in unique indexes. (Bug #27980) * *MySQL Cluster*: The name of the month `March' was given incorrectly in the cluster error log. (Bug #27926) * *MySQL Cluster*: *Note `NDB': mysql-cluster. tables having `MEDIUMINT AUTO_INCREMENT' columns were not restored correctly by *Note `ndb_restore': mysql-cluster-programs-ndb-restore, causing spurious duplicate key errors. This issue did not affect *Note `TINYINT': numeric-types, *Note `INT': numeric-types, or *Note `BIGINT': numeric-types. columns with `AUTO_INCREMENT'. (Bug #27775) * *MySQL Cluster*: *Note `NDB': mysql-cluster. tables with indexes whose names contained space characters were not restored correctly by *Note `ndb_restore': mysql-cluster-programs-ndb-restore. (the index names were truncated). (Bug #27758) * *MySQL Cluster*: An *Note `INSERT': insert. followed by a delete *Note `DELETE': delete. on the same *Note `NDB': mysql-cluster. table caused a memory leak. (Bug #27756) This regression was introduced by Bug #20612. * *MySQL Cluster*: It was not possible to add a unique index to an *Note `NDB': mysql-cluster. table while in single user mode. (Bug #27710) * *MySQL Cluster*: Under certain rare circumstances performing a *Note `DROP TABLE': drop-table. or *Note `TRUNCATE TABLE': truncate-table. on an *Note `NDB': mysql-cluster. table could cause a node failure or forced cluster shutdown. (Bug #27581) * *MySQL Cluster*: Memory usage of a *Note `mysqld': mysqld. process grew even while idle. (Bug #27560) * *MySQL Cluster*: Using more than 16GB for `DataMemory' caused problems with variable-size columns. (Bug #27512) * *MySQL Cluster*: A data node failing while another data node was restarting could leave the cluster in an inconsistent state. In certain rare cases, this could lead to a race condition and the eventual forced shutdown of the cluster. (Bug #27466) * *MySQL Cluster*: When using the `MemReportFrequency' configuration parameter to generate periodic reports of memory usage in the cluster log, `DataMemory' usage was not always reported for all data nodes. (Bug #27444) * *MySQL Cluster*: When trying to create an *Note `NDB': mysql-cluster. table after the server was started with `--ndbcluster' but without `--ndb-connectstring', *Note `mysqld': mysqld. produced a memory allocation error. (Bug #27359) * *MySQL Cluster*: Performing a delete followed by an insert during a local checkpoint could cause a `Rowid already allocated' error. (Bug #27205) * *MySQL Cluster*: In an *Note `NDB': mysql-cluster. table having a *Note `TIMESTAMP': datetime. column using `DEFAULT CURRENT_TIMESTAMP', that column would assume a random value when another column in the same row was updated. (Bug #27127) * *MySQL Cluster*: Error messages displayed when running in single user mode were inconsistent. (Bug #27021) * *MySQL Cluster*: On Solaris, the value of an *Note `NDB': mysql-cluster. table column declared as `BIT(33)' was always displayed as `0'. (Bug #26986) * *MySQL Cluster*: Performing `ALTER TABLE ... ENGINE=MERGE' on an *Note `NDB': mysql-cluster. table caused *Note `mysqld': mysqld. to crash. (Bug #26898) * *MySQL Cluster*: The *Note `NDBCLUSTER': mysql-cluster. table handler did not set bits in null bytes correctly. (Bug #26591) * *MySQL Cluster*: In some cases, `AFTER UPDATE' and `AFTER DELETE' triggers on *Note `NDB': mysql-cluster. tables that referenced subject table did not see the results of operation which caused invocation of the trigger, but rather saw the row as it was prior to the update or delete operation. This was most noticeable when an update operation used a subquery to obtain the rows to be updated. An example would be `UPDATE tbl1 SET col2 = val1 WHERE tbl1.col1 IN (SELECT col3 FROM tbl2 WHERE c4 = val2)' where there was an `AFTER UPDATE' trigger on table `tbl1'. In such cases, the trigger would fail to execute. The problem occurred because the actual update or delete operations were deferred to be able to perform them later as one batch. The fix for this bug solves the problem by disabling this optimization for a given update or delete if the table has an `AFTER' trigger defined for this operation. (Bug #26242) * *MySQL Cluster*: Joins on multiple tables containing *Note `BLOB': blob. columns could cause data nodes run out of memory, and to crash with the error `NdbObjectIdMap::expand unable to expand'. (Bug #26176) * *MySQL Cluster*: `START BACKUP NOWAIT' caused a spurious `Out of backup record' error in the management client (`START BACKUP' and `START BACKUP WAIT STARTED' performed normally). (Bug #25446) * *MySQL Cluster*: Adding of indexes online failed for *Note `NDB': mysql-cluster. tables having *Note `BLOB': blob. or *Note `TEXT': blob. columns. (Bug #25431) * *MySQL Cluster*: When a cluster data node suffered a `hard' failure (such as a power failure or loss of a network connection) TCP sockets to the missing node were maintained indefinitely. Now socket-based transporters check for a response and terminate the socket if there is no activity on the socket after 2 hours. (Bug #24793) * *MySQL Cluster*: The `ndb_resize.pl' utility did not calculate memory usage for indexes correctly. (Bug #24229) * *MySQL Cluster*: While a data node was stopped, dropping a table then creating an index on a different table caused that node to fail during restart. This was due to the re-use of the dropped table's internal ID for the index without verifying that the index now referred to a different database object. (Bug #21755) * *MySQL Cluster*: When trying to create tables on an SQL node not connected to the cluster, a misleading error message `Table 'TBL_NAME' already exists' was generated. The error now generated is `Could not connect to storage engine'. (Bug #11217, Bug #18676) * *Cluster Replication*: *Replication*: An SQL node acting as a replication master server could be a single point of failure; that is, if it failed, the replication slave had no way of knowing this, which could result in a mismatch of data between the master and the slave. (Bug #21494) * *Replication*: Out-of-memory errors were not reported. Now they are written to the error log. (Bug #26844) * *Replication*: Improved out-of-memory detection when sending logs from a master server to slaves, and log a message when allocation fails. (Bug #26837) * *Replication*: Aborting a statement on the master that applied to a nontransactional statement broke replication. The statement was written to the binary log but not completely executed on the master. Slaves receiving the statement executed it completely, resulting in loss of data synchrony. Now an error code is written to the error log so that the slaves stop without executing the aborted statement. (That is, replication stops, but synchrony to the point of the stop is preserved and you can investigate the problem.) (Bug #26551) * *Replication*: When `RAND()' was called multiple times inside a stored procedure, the server did not write the correct random seed values to the binary log, resulting in incorrect replication. (Bug #25543) * *Replication*: *Note `GRANT': grant. statements were not replicated if the server was started with the `--replicate-ignore-table' or `--replicate-wild-ignore-table' option. (Bug #25482) * *Replication*: Restoration of the default database after stored routine or trigger execution on a slave could cause replication to stop if the database no longer existed. (Bug #25082) * *Replication*: If a rotate event occurred in the middle of a nontransaction group, the group position would be updated by the rotate event indicating an illegal group start position that was effectively inside a group. This can happen if, for example, a rotate occurs between an `Intvar' event and the associated `Query' event, or between the table map events and the rows events when using row-based replication. (Bug #23171) * *Replication*: Row-based replication of `MyISAM' to non-`MyISAM' tables did not work correctly for *Note `BIT': numeric-types. columns. This has been corrected, but the fix introduces an incompatibility into the binary log format. (The incompatibility is corrected by the fix for Bug#27779.) (Bug #22583) * *Cluster Replication*: *Disk Data*: An issue with replication of Disk Data tables could in some cases lead to node failure. (Bug #28161) * *Disk Data*: Changes to a Disk Data table made as part of a transaction could not be seen by the client performing the changes until the transaction had been committed. (Bug #27757) * *Disk Data*: When in single user mode, it was possible to create log file groups and tablespaces from any SQL node connected to the cluster. (Bug #27712) * *Disk Data*: *Note `CREATE TABLE ... LIKE DISK_DATA_TABLE': create-table. created an in-memory *Note `NDB': mysql-cluster. table. (Bug #25875) * *Disk Data*: When restarting a data node following the creation of a large number of Disk Data objects (approximately 200 such objects), the cluster could not assign a node ID to the restarting node. (Bug #25741) * *Disk Data*: Creating an excessive number of Disk Data tables (1000 or more) could cause data nodes to fail. (Bug #24951) * *Disk Data*: Changing a column specification or issuing a *Note `TRUNCATE TABLE': truncate-table. statement on a Disk Data table caused the table to become an in-memory table. This fix supersedes an incomplete fix that was made for this issue in MySQL 5.1.15. (Bug #24667, Bug #25296) * *Disk Data*: Setting the value of the `UNDO BUFFER SIZE' to 64K or less in a *Note `CREATE LOGFILE GROUP': create-logfile-group. statement led to failure of cluster data nodes. (Bug #24560) * *Disk Data*: Creating an excessive number of data files for a single tablespace caused data nodes to crash. (Bug #24521) * *Disk Data*: It was possible to drop the last remaining datafile in a tablespace using *Note `ALTER TABLESPACE': alter-tablespace, even when there was still an empty table using the tablespace. *Note*: The datafile could be not dropped if the table still contained any rows, so this bug involved no loss of data. (Bug #21699) * *Cluster Replication*: Some queries that updated multiple tables were not backed up correctly. (Bug #27748) * *Cluster Replication*: It was possible for API nodes to begin interacting with the cluster subscription manager before they were fully connected to the cluster. (Bug #27728) * *Cluster Replication*: Under very high loads, checkpoints could be read or written with checkpoint indexes out of order. (Bug #27651) * *Cluster Replication*: Trying to replicate a large number of frequent updates with a relatively small relay log (`max-relay-log-size' set to 1M or less) could cause the slave to crash. (Bug #27529) * *Cluster Replication*: Setting `sql_log_bin' to zero did not disable binary logging. This issue affected only the *Note `NDB': mysql-cluster. storage engine. (Bug #27076) * *Cluster API*: For *Note `BLOB': blob. reads on operations with lock mode `LM_CommittedRead', the lock mode was not upgraded to `LM_Read' before the state of the *Note `BLOB': blob. had already been calculated. The *Note `NDB': mysql-cluster. API methods affected by this problem included the following: * `NdbOperation::readTuple()' * `NdbScanOperation::readTuples()' * `NdbIndexScanOperation::readTuples()' (Bug #27320) * *Cluster API*: Using `NdbBlob::writeData()' to write data in the middle of an existing blob value (that is, updating the value) could overwrite some data past the end of the data to be changed. (Bug #27018) * A performance degradation was observed for outer join queries to which a not-exists optimization was applied. (Bug #28188) * `SELECT * INTO OUTFILE ... FROM INFORMATION_SCHEMA.SCHEMATA' failed with an `Access denied' error, even for a user who had the `FILE' privilege. (Bug #28181) * Early `NULL'-filtering optimization did not work for `eq_ref' table access. (Bug #27939) * Nongrouped columns were permitted by `*' in `ONLY_FULL_GROUP_BY' SQL mode. (Bug #27874) * Some equi-joins containing a `WHERE' clause that included a `NOT IN' subquery caused a server crash. (Bug #27870) * An error message suggested the use of *Note `mysql_fix_privilege_tables': mysql-fix-privilege-tables. after an upgrade, but the recommended program is now *Note `mysql_upgrade': mysql-upgrade. (Bug #27818) * Debug builds on Windows generated false alarms about uninitialized variables with some Visual Studio runtime libraries. (Bug #27811) * Certain queries that used uncorrelated scalar subqueries caused *Note `EXPLAIN': explain. to crash. (Bug #27807) * Performing a *Note `UNION': union. on two views that had `ORDER BY' clauses resulted in an `Unknown column' error. (Bug #27786) * *Note `mysql_install_db': mysql-install-db. is supposed to detect existing system tables and create only those that do not exist. Instead, it was exiting with an error if tables already existed. (Bug #27783) * The `LEAST()' and `GREATEST()' functions compared *Note `DATE': datetime. and *Note `DATETIME': datetime. values as strings, which in some cases could lead to an incorrect result. (Bug #27759) * A memory leak in the event scheduler was uncovered by Valgrind. (Bug #27733) * *Note `mysqld': mysqld. did not check the length of option values and could crash with a buffer overflow for long values. (Bug #27715) * Comparisons using row constructors could fail for rows containing `NULL' values. (Bug #27704) * *Note `mysqldump': mysqldump. could not connect using SSL. (Bug #27669) * *Note `SELECT DISTINCT': select. could return incorrect results if the select list contained duplicated columns. (Bug #27659) * On Linux, the server could not create temporary tables if `lower_case_table_names' was set to 1 and the value of `tmpdir' was a directory name containing any uppercase letters. (Bug #27653) * For `InnoDB' tables, a multiple-row *Note `INSERT': insert. of the form `INSERT INTO t (id...) VALUES (NULL...) ON DUPLICATE KEY UPDATE id=VALUES(id)', where `id' is an `AUTO_INCREMENT' column, could cause `ERROR 1062 (23000): Duplicate entry...' errors or lost rows. (Bug #27650) * When MySQL logged slow query information to a `CSV' table, it used an incorrect formula to calculate the `query_time' and `lock_time' values. (Bug #27638) * The XML output representing an empty result was an empty string rather than an empty `' element. (Bug #27608) * Comparison of a *Note `DATE': datetime. with a *Note `DATETIME': datetime. did not treat the *Note `DATE': datetime. as having a time part of `00:00:00'. (Bug #27590) See also Bug #32198. * With `NO_AUTO_VALUE_ON_ZERO' SQL mode enabled, *Note `LOAD DATA': load-data. operations could assign incorrect `AUTO_INCREMENT' values. (Bug #27586) * Group relay log rotation updated only the log position and not the name, causing the slave to stop. (Bug #27583) * Incorrect results could be returned for some queries that contained a select list expression with `IN' or `BETWEEN' together with an `ORDER BY' or `GROUP BY' on the same expression using `NOT IN' or `NOT BETWEEN'. (Bug #27532) * The fix for Bug#17212 provided correct sort order for misordered output of certain queries, but caused significant overall query performance degradation. (Results were correct (good), but returned much more slowly (bad).) The fix also affected performance of queries for which results were correct. The performance degradation has been addressed. (Bug #27531) * The `CRC32()' function returns an unsigned integer, but the metadata was signed, which could cause certain queries to return incorrect results. (For example, queries that selected a `CRC32()' value and used that value in the `GROUP BY' clause.) (Bug #27530) * An interaction between *Note `SHOW TABLE STATUS': show-table-status. and other concurrent statements that modify the table could result in a divide-by-zero error and a server crash. (Bug #27516) * Evaluation of an `IN()' predicate containing a decimal-valued argument caused a server crash. (Bug #27513, Bug #27362, CVE-2007-2583) * A race condition between *Note `DROP TABLE': drop-table. and *Note `SHOW TABLE STATUS': show-table-status. could cause the latter to display incorrect information. (Bug #27499) * In out-of-memory conditions, the server might crash or otherwise not report an error to the Windows event log. (Bug #27490) * Passing nested row expressions with different structures to an `IN' predicate caused a server crash. (Bug #27484) * The `decimal.h' header file was incorrectly omitted from binary distributions. (Bug #27456) * With `innodb_file_per_table' enabled, attempting to rename an `InnoDB' table to a nonexistent database caused the server to exit. (Bug #27381) * Nested aggregate functions could be improperly evaluated. (Bug #27363) * A stored function invocation in the `WHERE' clause was treated as a constant. (Bug #27354) * For the `INFORMATION_SCHEMA' *Note `SESSION_STATUS': status-table. and *Note `GLOBAL_STATUS': status-table. tables, some status values were incorrectly converted to the data type of the `VARIABLE_VALUE' column. (Bug #27327) * Failure to allocate memory associated with `transaction_prealloc_size' could cause a server crash. (Bug #27322) * A subquery could get incorrect values for references to outer query columns when it contained aggregate functions that were aggregated in outer context. (Bug #27321) * The server did not shut down cleanly. (Bug #27310) * In a view, a column that was defined using a `GEOMETRY' function was treated as having the *Note `LONGBLOB': blob. data type rather than the `GEOMETRY' type. (Bug #27300) * *Note `mysqldump': mysqldump. crashed if it got no data from *Note `SHOW CREATE PROCEDURE': show-create-procedure. (for example, when trying to dump a routine defined by a different user and for which the current user had no privileges). Now it prints a comment to indicate the problem. It also returns an error, or continues if the `--force' option is given. (Bug #27293) * Queries containing subqueries with `COUNT(*)' aggregated in an outer context returned incorrect results. This happened only if the subquery did not contain any references to outer columns. (Bug #27257) * Use of an aggregate function from an outer context as an argument to `GROUP_CONCAT()' caused a server crash. (Bug #27229) * String truncation upon insertion into an integer or year column did not generate a warning (or an error in strict mode). (Bug #27176, Bug #26359) * *Note `mysqlbinlog': mysqlbinlog. produced different output with the `-R' option than without it. (Bug #27171) * Storing `NULL' values in spatial fields caused excessive memory allocation and crashes on some systems. (Bug #27164) * Row equalities in `WHERE' clauses could cause memory corruption. (Bug #27154) * `ON DUPLICATE KEY UPDATE' failed for a table partitioned by `KEY' on a primary key *Note `VARCHAR': char. column. (Bug #27123) * `GROUP BY' on a `ucs2' column caused a server crash when there was at least one empty string in the column. (Bug #27079) * Duplicate members in *Note `SET': set. or *Note `ENUM': enum. definitions were not detected. Now they result in a warning; if strict SQL mode is enabled, an error occurs instead. (Bug #27069) * For `FEDERATED' tables, *Note `SHOW CREATE TABLE': show-create-table. could fail when the table name was longer than the connection name. (Bug #27036) * *Note `mysql_install_db': mysql-install-db. could terminate with an error after failing to determine that a system table already existed. (Bug #27022) * In a `MEMORY' table, using a `BTREE' index to scan for updatable rows could lead to an infinite loop. (Bug #26996) * *Note `make_win_bin_dist': make-win-bin-dist. neglected to copy some required `MyISAM' table files. (Bug #26922) * For `InnoDB' tables having a clustered index that began with a *Note `CHAR': char. or *Note `VARCHAR': char. column, deleting a record and then inserting another before the deleted record was purged could result in table corruption. (Bug #26835) * *Note `mysqldump': mysqldump. would not dump a view for which the `DEFINER' no longer exists. (Bug #26817) * Duplicates were not properly identified among (potentially) long strings used as arguments for `GROUP_CONCAT(DISTINCT)'. (Bug #26815) * *Note `ALTER VIEW': alter-view. requires the `CREATE VIEW' and `DROP' privileges for the view. However, if the view was created by another user, the server erroneously required the `SUPER' privilege. (Bug #26813) * If the name of a table given to *Note `myisamchk -rq': myisamchk. was a packed table and the name included the `.MYI' extension, *Note `myisamchk': myisamchk. incorrectly created a file with a `.MYI.MYI' extension. (Bug #26782) * Creating a temporary table with `InnoDB' when using the one-file-per-table setting, and when the host file system for temporary tables was `tmpfs', would cause an assertion within `mysqld'. This was due to the use of `O_DIRECT' when opening the temporary table file. (Bug #26662) * *Note `mysql_upgrade': mysql-upgrade. did not detect failure of external commands that it runs. (Bug #26639) * The range optimizer could cause the server to run out of memory. (Bug #26625) * The range optimizer could consume a combinatorial amount of memory for certain classes of `WHERE' clauses. (Bug #26624) * `mysqldump' could crash or exhibit incorrect behavior when some options were given very long values, such as `--fields-terminated-by="SOME VERY LONG STRING"'. The code has been cleaned up to remove a number of fixed-sized buffers and to be more careful about error conditions in memory allocation. (Bug #26346) * A possible buffer overflow in *Note `SHOW PROCEDURE CODE': show-procedure-code. was removed. (Bug #26303) * The `FEDERATED' engine did not permit the local and remote tables to have different names. (Bug #26257) * The temporary file-creation code was cleaned up on Windows to improve server stability. (Bug #26233) * For `MyISAM' tables, `COUNT(*)' could return an incorrect value if the `WHERE' clause compared an indexed *Note `TEXT': blob. column to the empty string (`'''). This happened if the column contained empty strings and also strings starting with control characters such as tab or newline. (Bug #26231) * For *Note `INSERT INTO ... SELECT': insert-select. where index searches used column prefixes, insert errors could occur when key value type conversion was done. (Bug #26207) * *Note `mysqlbinlog --base64-output': mysqlbinlog. produced invalid SQL. (Bug #26194) * For `DELETE FROM `tbl_name' ORDER BY COL_NAME' (with no `WHERE' or `LIMIT' clause), the server did not check whether COL_NAME was a valid column in the table. (Bug #26186) * Executing an `INSERT ... SELECT ... FROM INFORMATION_SCHEMA.GLOBAL_STATUS' statement from within an event caused a server crash. (Bug #26174) * *Note `mysqldump': mysqldump. could not dump log tables. (Bug #26121) * On Windows, trying to use backslash (`\') characters in paths for `DATA DIRECTORY' and `INDEX DIRECTORY' when creating partitioned tables caused MySQL to crash. (You must use `/' characters when specifying paths for these options, regardless of platform. See *Note partitioning-overview::, for an example using absolute paths for `DATA DIRECTORY' and `INDEX DIRECTORY' when creating a partitioned table on Windows.) (Bug #26074, Bug #25141) * *Note `mysqldump': mysqldump. crashed for `MERGE' tables if the `--complete-insert' (`-c') option was given. (Bug #25993) * Index hints (`USE INDEX', `IGNORE INDEX', `FORCE INDEX') cannot be used with `FULLTEXT' indexes, but were not being ignored. (Bug #25951) * Setting a column to `NOT NULL' with an `ON DELETE SET NULL' clause foreign key crashes the server. (Bug #25927) * Corrupted `MyISAM' tables that have different definitions in the `.frm' and `.MYI' tables might cause a server crash. (Bug #25908) * If *Note `CREATE TABLE t1 LIKE t2': create-table. failed due to a full disk, an empty `t2.frm' file could be created but not removed. This file then caused subsequent attempts to create a table named `t2' to fail. This is easily corrected at the file system level by removing the `t2.frm' file manually, but now the server removes the file if the create operation does not complete successfully. (Bug #25761) * In certain situations, `MATCH ... AGAINST' returned false hits for `NULL' values produced by `LEFT JOIN' when no full-text index was available. (Bug #25729) * Concurrent *Note `CREATE SERVER': create-server. and *Note `ALTER SERVER': alter-server. statements could cause a deadlock. (Bug #25721) * *Note `CREATE SERVER': create-server, *Note `DROP SERVER': drop-server, and *Note `ALTER SERVER': alter-server. did not require any privileges. Now these statements require the `SUPER' privilege. (Bug #25671) * On Windows, connection handlers did not properly decrement the server's thread count when exiting. (Bug #25621) * *Note `OPTIMIZE TABLE': optimize-table. might fail on Windows when it attempts to rename a temporary file to the original name if the original file had been opened, resulting in loss of the `.MYD' file. (Bug #25521) * For *Note `SHOW ENGINE INNODB STATUS': show-engine, the `LATEST DEADLOCK INFORMATION' was not always cleared properly. (Bug #25494) * *Note `mysql_stmt_fetch()': mysql-stmt-fetch. did an invalid memory deallocation when used with the embedded server. (Bug #25492) * *Note `mysql_upgrade': mysql-upgrade. did not pass a password to *Note `mysqlcheck': mysqlcheck. if one was given. (Bug #25452) * On Windows, *Note `mysql_upgrade': mysql-upgrade. was sensitive to lettercase of the names of some required components. (Bug #25405) * During a call to *Note `mysql_change_user()': mysql-change-user, when authentication fails or the database to change to is unknown, a subsequent call to any function that does network communication leads to packets out of order. This problem was introduced in MySQL 5.1.14. (Bug #25371) * Difficult repair or optimization operations could cause an assertion failure, resulting in a server crash. (Bug #25289) * For storage engines that permit the current auto-increment value to be set, using `ALTER TABLE ... ENGINE' to convert a table from one such storage engine to another caused loss of the current value. (For storage engines that do not support setting the value, it cannot be retained anyway when changing the storage engine.) (Bug #25262) * Duplicate entries were not assessed correctly in a `MEMORY' table with a `BTREE' primary key on a `utf8' *Note `ENUM': enum. column. (Bug #24985) * Several math functions produced incorrect results for large unsigned values. `ROUND()' produced incorrect results or a crash for a large number-of-decimals argument. (Bug #24912) * The result set of a query that used `WITH ROLLUP' and `DISTINCT' could lack some rollup rows (rows with `NULL' values for grouping attributes) if the `GROUP BY' list contained constant expressions. (Bug #24856) * Selecting the result of `AVG()' within a *Note `UNION': union. could produce incorrect values. (Bug #24791) * For queries that used `ORDER BY' with `InnoDB' tables, if the optimizer chose an index for accessing the table but found a covering index that enabled the `ORDER BY' to be skipped, no results were returned. (Bug #24778) * The `NO_DIR_IN_CREATE' server SQL mode was not enforced for partitioned tables. (Bug #24633) * `MBRDisjoint()', `MBRequal()', `MBRIntersects()', `MBROverlaps()', `MBRTouches()', and `MBRWithin()' were inadvertently omitted from recent versions of MySQL (5.1.14 to 5.1.17). (Bug #24588) * Access through `my_pread()' or `my_pwrite()' to table files larger than 2GB could fail on some systems. (Bug #24566) * `MBROverlaps()' returned incorrect values in some cases. (Bug #24563) * A problem in handling of aggregate functions in subqueries caused predicates containing aggregate functions to be ignored during query execution. (Bug #24484) * The `MERGE' storage engine could return incorrect results when several index values that compare equality were present in an index (for example, `'gross'' and `'gross '', which are considered equal but have different lengths). (Bug #24342) * Some upgrade problems are detected and better error messages suggesting that *Note `mysql_upgrade': mysql-upgrade. be run are produced. (Bug #24248) * The test for the `MYSQL_OPT_SSL_VERIFY_SERVER_CERT' option for *Note `mysql_options()': mysql-options. was performed incorrectly. Also changed as a result of this bug fix: The `arg' option for the *Note `mysql_options()': mysql-options. C API function was changed from `char *' to `void *'. (Bug #24121) * Some views could not be created even when the user had the requisite privileges. (Bug #24040) * The values displayed for the `Innodb_row_lock_time', `Innodb_row_lock_time_avg', and `Innodb_row_lock_time_max' status variables were incorrect. (Bug #23666) * Using `CAST()' to convert *Note `DATETIME': datetime. values to numeric values did not work. (Bug #23656) * A damaged or missing `mysql.event' table caused *Note `SHOW VARIABLES': show-variables. to fail. (Bug #23631) * *Note `SHOW CREATE VIEW': show-create-view. qualified references to stored functions in the view definition with the function's database name, even when the database was the default database. This affected *Note `mysqldump': mysqldump. (which uses *Note `SHOW CREATE VIEW': show-create-view. to dump views) because the resulting dump file could not be used to reload the database into a different database. *Note `SHOW CREATE VIEW': show-create-view. now suppresses the database name for references to stored functions in the default database. (Bug #23491) * An `INTO OUTFILE' clause is permitted only for the final *Note `SELECT': select. of a *Note `UNION': union, but this restriction was not being enforced correctly. (Bug #23345) * The `AUTO_INCREMENT' value would not be correctly reported for `InnoDB' tables when using *Note `SHOW CREATE TABLE': show-create-table. statement or *Note `mysqldump': mysqldump. command. (Bug #23313) * With the `NO_AUTO_VALUE_ON_ZERO' SQL mode enabled, `LAST_INSERT_ID()' could return 0 after *Note `INSERT ... ON DUPLICATE KEY UPDATE': insert-on-duplicate. Additionally, the next rows inserted (by the same *Note `INSERT': insert, or the following *Note `INSERT': insert. with or without `ON DUPLICATE KEY UPDATE'), would insert 0 for the auto-generated value if the value for the `AUTO_INCREMENT' column was `NULL' or missing. (Bug #23233) * Implicit conversion of `9912101' to *Note `DATE': datetime. did not match `CAST(9912101 AS DATE)'. (Bug #23093) * `SELECT COUNT(*)' from a table containing a `DATETIME NOT NULL' column could produce spurious warnings with the `NO_ZERO_DATE' SQL mode enabled. (Bug #22824) * Using *Note `SET GLOBAL': set-option. to change the `lc_time_names' system variable had no effect on new connections. (Bug #22648) * `SOUNDEX()' returned an invalid string for international characters in multi-byte character sets. (Bug #22638) * A multiple-table *Note `UPDATE': update. could return an incorrect rows-matched value if, during insertion of rows into a temporary table, the table had to be converted from a `MEMORY' table to a `MyISAM' table. (Bug #22364) * `COUNT(DECIMAL_EXPR)' sometimes generated a spurious truncation warning. (Bug #21976) * yaSSL crashed on pre-Pentium Intel CPUs. (Bug #21765) * A slave that used `--master-ssl-cipher' could not connect to the master. (Bug #21611) * Database and table names have a maximum length of 64 characters (even if they contain multi-byte characters), but were truncated to 64 bytes. *Note*: This improves on a previous fix made for this bug in MySQL 5.1.12. (Bug #21432) * `InnoDB': The first read statement, if served from the query cache, was not consistent with the `READ COMMITTED' isolation level. (Bug #21409) * On Windows, if the server was installed as a service, it did not auto-detect the location of the data directory. (Bug #20376) * Changing a `utf8' column in an `InnoDB' table to a shorter length did not shorten the data values. (Bug #20095) * In some cases, the optimizer preferred a range or full index scan access method over lookup access methods when the latter were much cheaper. (Bug #19372) * Conversion of *Note `DATETIME': datetime. values in numeric contexts sometimes did not produce a double (`YYYYMMDDHHMMSS.uuuuuu') value. (Bug #16546) * `INSERT...ON DUPLICATE KEY UPDATE' could cause `Error 1032: Can't find record in ...' for inserts into an `InnoDB' table unique index using key column prefixes with an underlying `utf8' string column. (Bug #13191) * Having the `EXECUTE' privilege for a routine in a database should make it possible to *Note `USE': use. that database, but the server returned an error instead. This has been corrected. As a result of the change, *Note `SHOW TABLES': show-tables. for a database in which you have only the `EXECUTE' privilege returns an empty set rather than an error. (Bug #9504)  File: manual.info, Node: news-5-1-17, Next: news-5-1-16, Prev: news-5-1-18, Up: news-5-1-x D.1.51 Changes in MySQL 5.1.17 (04 April 2007) ---------------------------------------------- This is a new Beta development release, fixing recently discovered bugs. *Note*: This Beta release, as any other pre-production release, should not be installed on _production_ level systems or systems with critical data. It is good practice to back up your data before installing any new version of software. Although MySQL has worked very hard to ensure a high level of quality, protect your data by making a backup as you would for any software beta release. Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. This section documents all changes and bug fixes that have been applied since the last official MySQL release. If you would like to receive more fine-grained and personalized _update alerts_ about fixes that are relevant to the version and features you use, please consider subscribing to _MySQL Enterprise_ (a commercial MySQL offering). For more details, please see http://www.mysql.com/products/enterprise. *Functionality added or changed:* * *Incompatible Change*: Scheduled events now use the session time zone that is current when a *Note `CREATE EVENT': create-event. or *Note `ALTER EVENT': alter-event. statement executes is used to interpret times specified in the event definition (rather than UTC as in previous releases). The session time zone becomes the event time zone; that is, the time zone that is used for event scheduling and is in effect within the event as it executes. Because of this change, scheduled event metadata now includes time zone information, which can be seen in the `TIME_ZONE' column of the *Note `INFORMATION_SCHEMA.EVENTS': events-table. table and the `Time zone' column in the output of the *Note `SHOW EVENTS': show-events. statement. These columns have been added in this release, along with a `time_zone' column in the `mysql.event' table. Due to these changes, events created in previous versions of MySQL cannot be created, viewed, or used until `mysql.event' has been upgraded. For retrievals from `INFORMATION_SCHEMA.EVENTS' or *Note `SHOW EVENTS': show-events, times previously displayed using UTC now use the event time zone. (Bug #16420) * *Important Change*: *Replication*: The following options for controlling replication master configuration on a slave are now deprecated. * `--master-host' * `--master-user' * `--master-password ' * `--master-port' * `--master-connect-retry' * `--master-ssl' * `--master-ssl-ca' * `--master-ssl-capath' * `--master-ssl-cert' * `--master-ssl-cipher' * `--master-ssl-key' To change the master configuration on a slave you should use the *Note `CHANGE MASTER TO': change-master-to. statement. See also Bug #21490. * *Important Change*: The *Note `CREATE EVENT': create-event. and *Note `ALTER EVENT': alter-event. statements now support a `DEFINER' clause, similar to that used in the *Note `CREATE TRIGGER': create-trigger. statement. See *Note create-event::, for detailed information. (Bug #16425) * *MySQL Cluster*: Added the `--skip-table-check' option (short form `-s') for *Note `ndb_restore': mysql-cluster-programs-ndb-restore, which causes the restoration process to ignore any changes that may have occurred in table schemas after the backup was made. Previously, this was the default behavior. See *Note mysql-cluster-programs-ndb-restore::, for more information. (Bug #24363) * Added a `--no-beep' option to *Note `mysqladmin': mysqladmin. It suppresses the warning beep that is emitted by default for errors such as a failure to connect to the server. (Bug #26964) * Added the `--service-startup-timeout' option for *Note `mysql.server': mysql-server. to specify how long to wait for the server to start. If the server does not start within the timeout period, *Note `mysql.server': mysql-server. exits with an error. (Bug #26952) * Prefix lengths for columns in `SPATIAL' indexes can no longer be specified. For tables created in older versions of MySQL that have `SPATIAL' indexes containing prefixed columns, dumping and reloading the table causes the indexes to be created with no prefixes. (The full column width of each column is indexed.) (Bug #26794) * Added the `innodb_stats_on_metadata' system variable to enable control over whether `InnoDB' performs statistics gathering when metadata statements are executed. See *Note innodb-parameters::. (Bug #26598) * Statements that affect `mysql' database tables now are written to the binary log using the following rules: * Data manipulation statements such as *Note `INSERT': insert. that change data in `mysql' database tables directly are logged according to the settings of the `binlog_format' system variable. * Statements such as *Note `GRANT': grant. that change the `mysql' database indirectly are logged as statements regardless of the value of `binlog_format'. For more details, see *Note binary-log-mysql-database::. (Bug #25091) * The server now includes a timestamp in error messages that are logged as a result of unhandled signals (such as `mysqld got signal 11' messages). (Bug #24878) * The syntax for index hints has been extended to enable more fine-grained control over the optimizer's selection of an execution plan for various phases of query processing. See *Note index-hints::. (Bug #21174) * Added the `--secure-file-priv' option for *Note `mysqld': mysqld, which limits the effect of the `LOAD_FILE()' function and the *Note `LOAD DATA': load-data. and *Note `SELECT ... INTO OUTFILE': select. statements to work only with files in a given directory. (Bug #18628) * Prepared statements now use the query cache under the conditions described in *Note query-cache-operation::. (Bug #735) * Added the `thread_handling' system variable to control whether the server use a single thread or one thread per connection. The `--one-thread' option now is deprecated; use `--thread_handling=one-thread' instead. * Statements such as *Note `GRANT': grant. that change the `mysql' database indirectly are logged as statements regardless of the value of `binlog_format'. * Added the read-only `hostname' system variable, which the server sets at startup to the server host name. * For *Note `ALTER TABLE': alter-table, `ADD INDEX' and `DROP INDEX' operations for dynamic (variable-width) columns on *Note `NDB': mysql-cluster. tables are now performed as online (noncopying) operations. This is also true for *Note `CREATE INDEX': create-index. and *Note `DROP INDEX': drop-index. Renaming of *Note `NDB': mysql-cluster. and *Note `MyISAM': myisam-storage-engine. tables and of columns in such tables is now performed in place without copying or locking the tables. As a result, these operations are now performed much more quickly than previously. For more information, see *Note alter-table::, *Note create-index::, and *Note drop-index::. * Data manipulation statements such as *Note `INSERT': insert. that change data in `mysql' database tables directly are logged according to the settings of the `binlog_format' system variable. * Added the `old_mode' system variable to cause the server to revert to certain behaviors present in older versions. Currently, this variable affects handling of index hints. See *Note index-hints::. *Bugs fixed:* * *Incompatible Change*: *Note `INSERT DELAYED': insert-delayed. statements are not supported for `MERGE' tables, but the `MERGE' storage engine was not rejecting such statements, resulting in table corruption. Applications previously using *Note `INSERT DELAYED': insert-delayed. into `MERGE' table will break when upgrading to versions with this fix. To avoid the problem, remove `DELAYED' from such statements. (Bug #26464) * *Important Note*: The parser accepted invalid code in SQL condition handlers, leading to server crashes or unexpected execution behavior in stored programs. Specifically, the parser permitted a condition handler to refer to labels for blocks that enclose the handler declaration. This was incorrect because block label scope does not include the code for handlers declared within the labeled block. The parser now rejects this invalid construct, but if you perform a binary upgrade (without dumping and reloading your databases), existing handlers that contain the construct are still invalid and should be rewritten _even if they appear to function as you expect._ To find affected handlers, use *Note `mysqldump': mysqldump. to dump all stored procedures and functions, triggers, and events. Then attempt to reload them into an upgraded server. Handlers that contain illegal label references will be rejected. For more information about condition handlers and writing them to avoid invalid jumps, see *Note declare-handler::. (Bug #26503) * *MySQL Cluster*: It was not possible to set `LockPagesInMainMemory' equal to `0'. (Bug #27291) * *MySQL Cluster*: A race condition could sometimes occur if the node acting as master failed while node IDs were still being allocated during startup. (Bug #27286) * *MySQL Cluster*: When a data node was taking over as the master node, a race condition could sometimes occur as the node was assuming responsibility for handling of global checkpoints. (Bug #27283) * *MySQL Cluster*: After putting the cluster in single user mode from one MySQL server, trying to drop an *Note `NDB': mysql-cluster. table from a second MySQL server also connected to the cluster would cause the second MySQL server to hang. (Bug #27254) * *MySQL Cluster*: *Note `mysqld': mysqld. could crash shortly after a data node failure following certain DML operations. (Bug #27169) * *MySQL Cluster*: (Disk Data): Under some circumstances, a data node could fail during restart while flushing Disk Data UNDO logs. (Bug #27102) * *MySQL Cluster*: The same failed request from an API node could be handled by the cluster multiple times, resulting in reduced performance. (Bug #27087) * *MySQL Cluster*: The failure of a data node while restarting could cause other data nodes to hang or crash. (Bug #27003) * *MySQL Cluster*: Creating a table on one SQL node while in single user mode caused other SQL nodes to crash. (Bug #26997) * *MySQL Cluster*: *Note `mysqld': mysqld. processes would sometimes crash under high load. (Bug #26825) * *MySQL Cluster*: Using only the `--print_data' option (and no other options) with *Note `ndb_restore': mysql-cluster-programs-ndb-restore. caused *Note `ndb_restore': mysql-cluster-programs-ndb-restore. to fail. (Bug #26741) This regression was introduced by Bug #14612. * *MySQL Cluster*: The output from *Note `ndb_restore `--print_data'': mysql-cluster-programs-ndb-restore. was incorrect for a backup made of a database containing tables with *Note `TINYINT': numeric-types. or *Note `SMALLINT': numeric-types. columns. (Bug #26740) * *MySQL Cluster*: An infinite loop in an internal logging function could cause trace logs to fill up with `Unknown Signal type' error messages and thus grow to unreasonable sizes. (Bug #26720) * *MySQL Cluster*: An invalid pointer was returned following a `FSCLOSECONF' signal when accessing the REDO logs during a node restart or system restart. (Bug #26515) * *MySQL Cluster*: The management client command ` NODE_ID STATUS' displayed the message `Node NODE_ID: not connected' when NODE_ID was not the node ID of a data node. *Note*: The `ALL STATUS' command in the cluster management client still displays status information for data nodes only. This is by design. See *Note mysql-cluster-mgm-client-commands::, for more information. (Bug #21715) * *MySQL Cluster*: When performing an upgrade or downgrade, no specific error information was made available when trying to upgrade data nodes or SQL nodes before upgrading management nodes. (Bug #21296) * *MySQL Cluster*: Some values of `MaxNoOfTables' caused the error `Job buffer congestion' to occur. (Bug #19378) * *Replication*: A multiple-row delayed insert with an auto-increment column could cause duplicate entries to be created on the slave in a replication environment. (Bug #26116, Bug #25507) * *Replication*: Duplicating the usage of a user variable in a stored procedure or trigger would not be replicated correctly to the slave. (Bug #25167) * *Replication*: *Note `DROP TRIGGER': drop-trigger. statements would not be filtered on the slave when using the `replication-wild-do-table' option. (Bug #24478) * *Replication*: For *Note `INSERT ... ON DUPLICATE KEY UPDATE': insert-on-duplicate. statements where some `AUTO_INCREMENT' values were generated automatically for inserts and some rows were updated, one auto-generated value was lost per updated row, leading to faster exhaustion of the range of the `AUTO_INCREMENT' column. Because the original problem can affect replication (different values on master and slave), it is recommended that the master and its slaves be upgraded to the current version. (Bug #24432) * *Replication*: Replication between master and slave would infinitely retry binary log transmission where the `max_allowed_packet' on the master was larger than that on the slave if the size of the transfer was between these two values. (Bug #23775) * *Replication*: Loading data using *Note `LOAD DATA INFILE': load-data. may not replicate correctly (due to character set incompatibilities) if the `character_set_database' variable is set before the data is loaded. (Bug #15126) * *Replication*: User defined variables used within stored procedures and triggers are not replicated correctly when operating in statement-based replication mode. (Bug #14914, Bug #20141) * *Disk Data*: A memory overflow could occur with tables having a large amount of data stored on disk, or with queries using a very high degree of parallelism on Disk Data tables. (Bug #26514) * *Disk Data*: Use of a tablespace whose `INITIAL_SIZE' was greater than 1 GB could cause the cluster to crash. (Bug #26487) * *Disk Data*: Creating multiple Disk Data tables using different tablespaces could sometimes cause the cluster to fail. (Bug #25992) * *Disk Data*: `ALTER TABLE ... ADD COLUMN ...' on a Disk Data table moved data for existing nonindexed columns from the tablespace into memory. (Bug #25880) * *Disk Data*: *Note `DROP INDEX': drop-index. on a Disk Data table did not always move data from memory into the tablespace. (Bug #25877) * *Disk Data*: When creating a log file group, setting `INITIAL_SIZE' to less than `UNDO_BUFFER_SIZE' caused data nodes to crash. (Bug #25743) * *Cluster Replication*: The simultaneous failure of a data node and an SQL node could cause replication to fail. (Bug #27005) * *Cluster API*: A delete operation using a scan followed by an insert using a scan could cause a data node to fail. (Bug #27203) * *Cluster API*: `NAND' and `NOR' operations with `NdbScanFilter' did not perform correctly. (Bug #24568) * *Cluster API*: You can now use the `ndb_mgm_check_connection()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-check-connection.html) function to determine whether a management server is running. * *Note `MyISAM': myisam-storage-engine. tables converted to *Note `ARCHIVE': archive-storage-engine. were excessively large. (Bug #27533) * *Note `SELECT ... INTO OUTFILE': select. with a long `FIELDS ENCLOSED BY' value could crash the server. (Bug #27231) * An *Note `INSERT ... ON DUPLICATE KEY UPDATE': insert-on-duplicate. statement might modify values in a table but not flush affected data from the query cache, causing subsequent selects to return stale results. This made the combination of query cache plus `ON DUPLICATE KEY UPDATE' very unreliable. (Bug #27210) See also Bug #27006, Bug #27033. This regression was introduced by Bug #19978. * For *Note `INSERT ... ON DUPLICATE KEY UPDATE': insert-on-duplicate. statements on tables containing `AUTO_INCREMENT' columns, `LAST_INSERT_ID()' was reset to 0 if no rows were successfully inserted or changed. `Not changed' includes the case where a row was updated to its current values, but in that case, `LAST_INSERT_ID()' should not be reset to 0. Now `LAST_INSERT_ID()' is reset to 0 only if no rows were successfully inserted or touched, whether or not touched rows were changed. (Bug #27033) See also Bug #27210, Bug #27006. This regression was introduced by Bug #19978. * Invalid optimization of pushdown conditions for queries where an outer join was guaranteed to read only one row from the outer table led to results with too few rows. (Bug #26963) * For `MERGE' tables defined on underlying tables that contained a short *Note `VARCHAR': char. column (shorter than four characters), using *Note `ALTER TABLE': alter-table. on at least one but not all of the underlying tables caused the table definitions to be considered different from that of the `MERGE' table, even if the *Note `ALTER TABLE': alter-table. did not change the definition. (Bug #26881) * Use of a subquery containing `GROUP BY' and `WITH ROLLUP' caused a server crash. (Bug #26830) * Setting `event_scheduler = 1' or `event_scheduler = ON' caused the server to crash if the server had been started with `--skip-grant-tables'. Starting the server with `--skip-grant-tables' now causes `event_scheduler' to be set to `DISABLED' automatically, overriding any other value that may have been set. (Bug #26807) * Added support for `--debugger=dbx' for `mysql-test-run.pl' and added support for `--debugger=devenv', `--debugger=DevEnv', and `--debugger=/PATH/TO/devenv'. (Bug #26792) * A result set column formed by concatention of string literals was incomplete when the column was produced by a subquery in the `FROM' clause. (Bug #26738) * SSL connections failed on Windows. (Bug #26678) * When using the result of `SEC_TO_TIME()' for time value greater than 24 hours in an `ORDER BY' clause, either directly or through a column alias, the rows were sorted incorrectly as strings. (Bug #26672) * Use of a subquery containing a *Note `UNION': union. with an invalid `ORDER BY' clause caused a server crash. (Bug #26661) * In some error messages, inconsistent format specifiers were used for the translations in different languages. *Note `comp_err': comp-err. (the error message compiler) now checks for mismatches. (Bug #26571) * Views that used a scalar correlated subquery returned incorrect results. (Bug #26560) * `UNHEX() IS NULL' comparisons failed when `UNHEX()' returned `NULL'. (Bug #26537) * On 64-bit Windows, large timestamp values could be handled incorrectly. (Bug #26536) * *Note `SHOW CREATE EVENT': show-create-event. failed to display the `STARTS' and `ENDS' clauses for an event defined with `STARTS NOW()', `ENDS NOW()', or both. (Bug #26429) * If the server was started with `--skip-grant-tables', Selecting from `INFORMATION_SCHEMA' tables causes a server crash. (Bug #26285) * For some values of the position argument, the `INSERT()' function could insert a NUL byte into the result. (Bug #26281) * For an *Note `INSERT': insert. statement that should fail due to a column with no default value not being assigned a value, the statement succeeded with no error if the column was assigned a value in an `ON DUPLICATE KEY UPDATE' clause, even if that clause was not used. (Bug #26261) * *Note `INSERT DELAYED': insert-delayed. statements inserted incorrect values into *Note `BIT': numeric-types. columns. (Bug #26238) * A query of type `index_merge', and with a `WHERE' clause having the form `WHERE INDEXED_COLUMN_1=VALUE_1 OR INDEXED_COLUMN_2=VALUE_2 ' on a partitioned table caused the server to crash. (Bug #26117) * `BENCHMARK()' did not work correctly for expressions that produced a *Note `DECIMAL': numeric-types. result. (Bug #26093) * For `MEMORY' tables, extending the length of a *Note `VARCHAR': char. column with *Note `ALTER TABLE': alter-table. might result in an unusable table. (Bug #26080) * The server could hang during binary log rotation. (Bug #26079) * *Note `LOAD DATA INFILE': load-data. sent an okay to the client before writing the binary log and committing the changes to the table had finished, thus violating ACID requirements. (Bug #26050) * `X() IS NULL' and `Y() IS NULL' comparisons failed when `X()' and `Y()' returned `NULL'. (Bug #26038) * Indexes on *Note `TEXT': blob. columns were ignored when `ref' accesses were evaluated. (Bug #25971) * If a thread previously serviced a connection that was killed, excessive memory and CPU use by the thread occurred if it later serviced a connection that had to wait for a table lock. (Bug #25966) * `VIEW' restrictions were applied to *Note `SELECT': select. statements after a *Note `CREATE VIEW': create-view. statement failed, as though the `CREATE' had succeeded. (Bug #25897) * Several deficiencies in resolution of column names for *Note `INSERT ... SELECT': insert-select. statements were corrected. (Bug #25831) * Inserting `utf8' data into a *Note `TEXT': blob. column that used a single-byte character set could result in spurious warnings about truncated data. (Bug #25815) * On Windows, debug builds of *Note `mysqld': mysqld. could fail with heap assertions. (Bug #25765) * In certain cases it could happen that deleting a row corrupted an `RTREE' index. This affected indexes on spatial columns. (Bug #25673) * Using *Note `mysqlbinlog': mysqlbinlog. on a binary log would crash if there were a large number of row-based events related to a single statement. (Bug #25628) * Expressions involving `SUM()', when used in an `ORDER BY' clause, could lead to out-of-order results. (Bug #25376) * Use of a `GROUP BY' clause that referred to a stored function result together with `WITH ROLLUP' caused incorrect results. (Bug #25373) * A stored procedure that made use of cursors failed when the procedure was invoked from a stored function. (Bug #25345) * On Windows, the server exhibited a file-handle leak after reaching the limit on the number of open file descriptors. (Bug #25222) * The `REPEAT()' function did not permit a column name as the COUNT parameter. (Bug #25197) * A reference to a nonexistent column in the `ORDER BY' clause of an `UPDATE ... ORDER BY' statement could cause a server crash. (Bug #25126) * A view on a join is insertable for *Note `INSERT': insert. statements that store values into only one table of the join. However, inserts were being rejected if the inserted-into table was used in a self-join because MySQL incorrectly was considering the insert to modify multiple tables of the view. (Bug #25122) * Creating a table with latin characters in the name caused the output of `SHOW FULL TABLES' to have `ERROR' for the table type. (Bug #25081) * MySQL would not compile when configured using `--without-query-cache'. (Bug #25075) * It was not possible to use XPath keywords as tag names for expressions used in the `ExtractValue()' function. (Bug #24747) * Increasing the width of a *Note `DECIMAL': numeric-types. column could cause column values to be changed. (Bug #24558) * IF(EXPR, UNSIGNED_EXPR, UNSIGNED_EXPR) was evaluated to a signed result, not unsigned. This has been corrected. The fix also affects constructs of the form `IS [NOT] {TRUE|FALSE}', which were transformed internally into `IF()' expressions that evaluated to a signed result. For existing views that were defined using `IS [NOT] {TRUE|FALSE}' constructs, there is a related implication. The definitions of such views were stored using the `IF()' expression, not the original construct. This is manifest in that *Note `SHOW CREATE VIEW': show-create-view. shows the transformed `IF()' expression, not the original one. Existing views will evaluate correctly after the fix, but if you want *Note `SHOW CREATE VIEW': show-create-view. to display the original construct, you must drop the view and re-create it using its original definition. New views will retain the construct in their definition. (Bug #24532) * `SHOW ENGINE MUTEX STATUS' failed to produce an `Unknown table engine' error. See *Note show-engine::. (Bug #24392) * A user-defined variable could be assigned an incorrect value if a temporary table was employed in obtaining the result of the query used to determine its value. (Bug #24010) * *Note `mysqlimport': mysqlimport. used a variable of the wrong type for the `--use-threads' option, which could cause a crash on some architectures. (Bug #23814) * Queries that used a temporary table for the outer query when evaluating a correlated subquery could return incorrect results. (Bug #23800) * On Windows, debug builds of *Note `mysqlbinlog': mysqlbinlog. could fail with a memory error. (Bug #23736) * When using certain server SQL modes, the `mysql.proc' table was not created by *Note `mysql_install_db': mysql-install-db. (Bug #23669) * *Note `DOUBLE': numeric-types. values such as `20070202191048.000000' were being treated as illegal arguments by `WEEK()'. (Bug #23616) * The server could crash if two or more threads initiated query cache resize operation at moments very close in time. (Bug #23527) * `NOW()' returned the wrong value in statements executed at server startup with the `--init-file' option. (Bug #23240) * Setting the `slow_query_log_file' system variable caused log output to go tothe general log, not the slow query log. (Bug #23225) * When nesting stored procedures within a trigger on a table, a false dependency error was thrown when one of the nested procedures contained a *Note `DROP TABLE': drop-table. statement. (Bug #22580) * Instance Manager did not remove the angel PID file on a clean shutdown. (Bug #22511) * *Note `EXPLAIN EXTENDED': explain. did not show `WHERE' conditions that were optimized away. (Bug #22331) * `IN ((SUBQUERY))', `IN (((SUBQUERY)))', and so forth, are equivalent to `IN (SUBQUERY)', which is always interpreted as a table subquery (so that it is permitted to return more than one row). MySQL was treating the `over-parenthesized' subquery as a single-row subquery and rejecting it if it returned more than one row. This bug primarily affected automatically generated code (such as queries generated by Hibernate), because humans rarely write the over-parenthesized forms. (Bug #21904) * An *Note `INSERT': insert. trigger invoking a stored routine that inserted into a table other than the one on which the trigger was defined would fail with a `Table '...' doesn't exist' referring to the second table when attempting to delete records from the first table. (Bug #21825) * `CURDATE()' is less than `NOW()', either when comparing `CURDATE()' directly (`CURDATE() < NOW()' is true) or when casting `CURDATE()' to *Note `DATE': datetime. (`CAST(CURDATE() AS DATE) < NOW()' is true). However, storing `CURDATE()' in a *Note `DATE': datetime. column and comparing `COL_NAME < NOW()' incorrectly yielded false. This is fixed by comparing a *Note `DATE': datetime. column as *Note `DATETIME': datetime. for comparisons to a *Note `DATETIME': datetime. constant. (Bug #21103) * When a stored routine attempted to execute a statement accessing a nonexistent table, the error was not caught by the routine's exception handler. (Bug #20713, Bug #8407) * For a stored procedure containing a *Note `SELECT': select. statement that used a complicated join with an `ON' expression, the expression could be ignored during re-execution of the procedure, yielding an incorrect result. (Bug #20492) * The conditions checked by the optimizer to permit use of indexes in `IN' predicate calculations were unnecessarily tight and were relaxed. (Bug #20420) * When a `TIME_FORMAT()' expression was used as a column in a `GROUP BY' clause, the expression result was truncated. (Bug #20293) * The creation of MySQL system tables was not checked for by `mysql-test-run.pl'. (Bug #20166) * For index reads, the `BLACKHOLE' engine did not return end-of-file (which it must because `BLACKHOLE' tables contain no rows), causing some queries to crash. (Bug #19717) * For `EXPR IN(VALUE_LIST)', the result could be incorrect if `BIGINT UNSIGNED' values were used for EXPR or in the value list. (Bug #19342) * When attempting to call a stored procedure creating a table from a trigger on a table `tbl' in a database `db', the trigger failed with `ERROR 1146 (42S02): Table 'db.tbl' doesn't exist'. However, the actual reason that such a trigger fails is due to the fact that *Note `CREATE TABLE': create-table. causes an implicit *Note `COMMIT': commit, and so a trigger cannot invoke a stored routine containing this statement. A trigger which does so now fails with `ERROR 1422 (HY000): Explicit or implicit commit is not permitted in stored function or trigger', which makes clear the reason for the trigger's failure. (Bug #18914) * While preparing prepared statements, the server acquired unnecessary table write locks. (Bug #18326) * The update columns for `INSERT ... SELECT ... ON DUPLICATE KEY UPDATE' could be assigned incorrect values if a temporary table was used to evaluate the *Note `SELECT': select. (Bug #16630) * For `SUBSTRING()' evaluation using a temporary table, when `SUBSTRING()' was used on a LONGTEXT column, the `max_length' metadata value of the result was incorrectly calculated and set to 0. Consequently, an empty string was returned instead of the correct result. (Bug #15757) * Local variables in stored routines or triggers, when declared as the *Note `BIT': numeric-types. type, were interpreted as strings. (Bug #12976) * For some operations, system tables in the `mysql' database must be accessed. For example, the *Note `HELP': help. statement requires the contents of the server-side help tables, and `CONVERT_TZ()' might need to read the time zone tables. However, to perform such operations while a *Note `LOCK TABLES': lock-tables. statement is in effect, the server required you to also lock the requisite system tables explicitly or a lock error occurred: mysql> LOCK TABLE t1 READ; Query OK, 0 rows affected (0.02 sec) mysql> HELP HELP; ERROR 1100 (HY000) at line 4: Table 'help_topic' was not locked with LOCK TABLES Now, the server implicitly locks the system tables for reading as necessary so that you need not lock them explicitly. These tables are treated as just described: mysql.help_category mysql.help_keyword mysql.help_relation mysql.help_topic mysql.proc mysql.time_zone mysql.time_zone_leap_second mysql.time_zone_name mysql.time_zone_transition mysql.time_zone_transition_type If you want to explicitly place a `WRITE' lock on any of those tables with a *Note `LOCK TABLES': lock-tables. statement, the table must be the only one locked; no other table can be locked with the same statement. (Bug #9953)  File: manual.info, Node: news-5-1-16, Next: news-5-1-15, Prev: news-5-1-17, Up: news-5-1-x D.1.52 Changes in MySQL 5.1.16 (26 February 2007) ------------------------------------------------- This is a new Beta development release, fixing recently discovered bugs. *Note*: This Beta release, as any other pre-production release, should not be installed on _production_ level systems or systems with critical data. It is good practice to back up your data before installing any new version of software. Although MySQL has worked very hard to ensure a high level of quality, protect your data by making a backup as you would for any software beta release. Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. *Note*: After release, a trigger failure problem was found to have been introduced. (Bug#27006) Users affected by this issue should upgrade to MySQL 5.1.17, which corrects the problem. This section documents all changes and bug fixes that have been applied since the last official MySQL release. If you would like to receive more fine-grained and personalized _update alerts_ about fixes that are relevant to the version and features you use, please consider subscribing to _MySQL Enterprise_ (a commercial MySQL offering). For more details, please see http://www.mysql.com/products/enterprise. *Functionality added or changed:* * *Cluster API*: *Incompatible Change*: The `AbortOption' type is now a member of the `NdbOperation' class; its values and behavior have also changed. `NdbTransaction::AbortOption' can no longer be used, and applications written against the NDB API may need to be rewritten and recompiled to accommodate these changes. For more information about this change, see The `NdbOperation::AbortOption' Type (http://dev.mysql.com/doc/ndbapi/en/ndb-ndboperation-types.html#ndb-ndboperation-abortoption). This also affects the behavior of the `NdbTransaction::execute()' method, which now reports failure only if the transaction was actually aborted. * *MySQL Cluster*: Previously, when a data node failed to start more than 8 times in succession, this caused a forced shutdown of the cluster. Now, when a data node fails to start 7 consecutive times, the node does not start again until it is started with the `--initial' option, and a warning to this effect is written to the error log. (Bug #25984) * *MySQL Cluster*: In the event that all cluster management and API nodes are configured with `ArbitrationRank = 0', *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. now issues the following warning when starting: `Cluster configuration warning: Neither MGM nor API nodes are configured with arbitrator, may cause complete cluster shutdown in case of host failure'. (Bug #23546) * *MySQL Cluster*: A number of new and more descriptive error messages covering transporter errors were added. (Bug #22025) * *MySQL Cluster*: A new configuration parameter `MemReportFrequency' enables additional control of data node memory usage. Previously, only warnings at predetermined percentages of memory allocation were given; setting this parameter enables that behavior to be overridden. * *Cluster API*: A new `ndb_mgm_get_clusterlog_loglevel()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-get-clusterlog-loglevel.html) function was added to the MGM API. * The `localhost' anonymous user account created during MySQL installation on Windows now has no global privileges. Formerly this account had all global privileges. For operations that require global privileges, the `root' account can be used instead. (Bug #24496) * In the `INFORMATION_SCHEMA' *Note `REFERENTIAL_CONSTRAINTS': referential-constraints-table. table, the `UNIQUE_CONSTRAINT_NAME' column incorrectly named the referenced table. Now it names the referenced constraint, and a new column, `REFERENCED_TABLE_NAME', names the referenced table. (Bug #21713) * `RAND()' now permits nonconstant initializers (such as a column name) as its argument. In this case, the seed is initialized with the value for each invocation of `RAND()'. (One implication of this is that for equal argument values, `RAND()' will return the same value each time.) (Bug #6172) * Added the `--auto-generate-sql-load-type' and `--auto-generate-sql-write-number' options for *Note `mysqlslap': mysqlslap. * The bundled yaSSL library was upgraded to version 1.5.8. *Bugs fixed:* * *Security Fix*: Using an `INFORMATION_SCHEMA' table with `ORDER BY' in a subquery could cause a server crash. We would like to thank Oren Isacson of Flowgate Security Consulting and Stefan Streichsbier of SEC Consult for informing us of this problem. (Bug #24630, Bug #26556, CVE-2007-1420) * *Partitioning*: *MySQL Cluster*: A query with an `IN' clause against an *Note `NDB': mysql-cluster. table employing explicit user-defined partitioning did not always return all matching rows. (Bug #25821) * *MySQL Cluster*: *Replication*: (Replication): Under some circumstances, the binary log thread could shut down while the slave SQL thread was still using it. (Bug #26015, Bug #26019) * *MySQL Cluster*: *Replication*: (Replication): The error message `Last_Errno: 4294967295, Error in Write_rows event' now supplies a valid error code. (Bug #19896) * *MySQL Cluster*: An inadvertent use of unaligned data caused *Note `ndb_restore': mysql-cluster-programs-ndb-restore. to fail on some 64-bit platforms, including Sparc and Itanium-2. (Bug #26739) * *MySQL Cluster*: The InvalidUndoBufferSize error used the same error code (763) as the IncompatibleVersions error. InvalidUndoBufferSize now uses its own error code (779). (Bug #26490) * *MySQL Cluster*: The failure of a data node when restarting it with `--initial' could lead to failures of subsequent data node restarts. (Bug #26481) * *MySQL Cluster*: Takeover for local checkpointing due to multiple failures of master nodes was sometimes incorrectly handled. (Bug #26457) * *MySQL Cluster*: The `LockPagesInMainMemory' parameter was not read until after distributed communication had already started between cluster nodes. When the value of this parameter was `1', this could sometimes result in data node failure due to missed heartbeats. (Bug #26454) * *MySQL Cluster*: Under some circumstances, following the restart of a management node, all data nodes would connect to it normally, but some of them subsequently failed to log any events to the management node. (Bug #26293) * *MySQL Cluster*: Condition pushdown did not work with prepared statements. (Bug #26225) * *MySQL Cluster*: A memory leak could cause problems during a node or cluster shutdown or failure. (Bug #25997) * *MySQL Cluster*: No appropriate error message was provided when there was insufficient REDO log file space for the cluster to start. (Bug #25801) * *MySQL Cluster*: An *Note `UPDATE': update. using an `IN' clause on an *Note `NDB': mysql-cluster. table on which there was a trigger caused *Note `mysqld': mysqld. to crash. (Bug #25522) * *MySQL Cluster*: A memory allocation failure in `SUMA' (the cluster Subscription Manager) could cause the cluster to crash. (Bug #25239) * *MySQL Cluster*: The `ndb_size.tmpl' file (necessary for using the `ndb_size.pl' script) was missing from binary distributions. (Bug #24191) * *MySQL Cluster*: The message `Error 0 in readAutoIncrementValue(): no Error' was written to the error log whenever *Note `SHOW TABLE STATUS': show-table-status. was performed on a Cluster table that did not have an `AUTO_INCREMENT' column. *Note*: This improves on and supersedes an earlier fix that was made for this issue in MySQL 5.1.12. (Bug #21033) * *MySQL Cluster*: When a node failed due to there being insufficient disk space to perform a local checkpoint, there was no indication that this was the source of the problem. Such a condition now produces an appropriate error message. (Bug #20121) * *MySQL Cluster*: In the event that cluster backup parameters such as `BackupWriteSize' were incorrectly set, no appropriate error was issued to indicate that this was the case. (Bug #19146) * *Replication*: If a slave server closed its relay log (for example, due to an error during log rotation), the I/O thread did not recognize this and still tried to write to the log, causing a server crash. (Bug #10798) * *Cluster API*: *Disk Data*: A delete and a read performed in the same operation could cause one or more data nodes to crash. This could occur when the operation affected more than 5 columns concurrently, or when one or more of the columns was of the *Note `VARCHAR': char. type and was stored on disk. (Bug #25794) * *Cluster API*: After defining a delete operation (using `NdbOperation::deleteTuple()') on a nonexistent primary key of a table having a *Note `BLOB': blob. or *Note `TEXT': blob. column, invoking `NdbTransaction::execute()' caused the calling application to enter an endless loop rather than raising an error. This issue also affected *Note `ndb_restore': mysql-cluster-programs-ndb-restore.; when restoring tables containing *Note `BLOB': blob. or *Note `TEXT': blob. columns, this could cause it to consume all available memory and then crash. (Bug #24028) See also Bug #27308, Bug #30177. * *Cluster API*: `libndbclient.so' was not versioned. (Bug #13522) * Using `ORDER BY' or `GROUP BY' could yield different results when selecting from a view and selecting from the underlying table. (Bug #26209) * `DISTINCT' queries that were executed using a loose scan for an `InnoDB' table that had been emptied caused a server crash. (Bug #26159) * A `WHERE' clause that used `BETWEEN' for *Note `DATETIME': datetime. values could be treated differently for a *Note `SELECT': select. and a view defined as that *Note `SELECT': select. (Bug #26124) * Collation for `LEFT JOIN' comparisons could be evaluated incorrectly, leading to improper query results. (Bug #26017) * The `WITH CHECK OPTION' clause for views was ignored for updates of multiple-table views when the updates could not be performed on fly and the rows to update had to be put into temporary tables first. (Bug #25931) * *Note `LOAD DATA INFILE': load-data. did not work with pipes. (Bug #25807) * The `SEC_TO_TIME()' and `QUARTER()' functions sometimes did not handle `NULL' values correctly. (Bug #25643) * View definitions that used the `!' operator were treated as containing the `NOT' operator, which has a different precedence and can produce different results. . (Bug #25580) * An error in the name resolution of nested `JOIN ... USING' constructs was corrected. (Bug #25575) * `GROUP BY' and `DISTINCT' did not group `NULL' values for columns that have a `UNIQUE' index. . (Bug #25551) * The `--with-readline' option for `configure' did not work for commercial source packages, but no error message was printed to that effect. Now a message is printed. (Bug #25530) * A yaSSL program named `test' was installed, causing conflicts with the `test' system utility. It is no longer installed. (Bug #25417) * For a `UNIQUE' index containing many `NULL' values, the optimizer would prefer the index for `COL IS NULL' conditions over other more selective indexes. . (Bug #25407) * An `AFTER UPDATE' trigger on an `InnoDB' table with a composite primary key caused the server to crash. (Bug #25398) * Passing a `NULL' value to a user-defined function from within a stored procedure crashes the server. (Bug #25382) * *Note `perror': perror. crashed on some platforms due to failure to handle a `NULL' pointer. (Bug #25344) * *Note `mysql.server stop': mysql-server. timed out too quickly (35 seconds) waiting for the server to exit. Now it waits up to 15 minutes, to ensure that the server exits. (Bug #25341) * A query that contained an `EXIST' subquery with a *Note `UNION': union. over correlated and uncorrelated *Note `SELECT': select. queries could cause the server to crash. (Bug #25219) * *Note `mysql_kill()': mysql-kill. caused a server crash when used on an SSL connection. (Bug #25203) * yaSSL was sensitive to the presence of whitespace at the ends of lines in PEM-encoded certificates, causing a server crash. (Bug #25189) * A query with `ORDER BY' and `GROUP BY' clauses where the `ORDER BY' clause had more elements than the `GROUP BY' clause caused a memory overrun leading to a crash of the server. (Bug #25172) * Use of `ON DUPLICATE KEY UPDATE' defeated the usual restriction against inserting into a join-based view unless only one of the underlying tables is used. (Bug #25123) * `ALTER TABLE ... ENABLE KEYS' acquired a global lock, preventing concurrent execution of other statements that use tables. . (Bug #25044) * *Note `OPTIMIZE TABLE': optimize-table. caused a race condition in the I/O cache. (Bug #25042) * A return value of `-1' from user-defined handlers was not handled well and could result in conflicts with server code. (Bug #24987) * Certain joins using `Range checked for each record' in the query execution plan could cause the server to crash. (Bug #24776) * *Note `ALTER TABLE': alter-table. caused loss of `CASCADE' clauses for `InnoDB' tables. (Bug #24741) * If an `ORDER BY' or `GROUP BY' list included a constant expression being optimized away and, at the same time, containing single-row subselects that returned more that one row, no error was reported. If a query required sorting by expressions containing single-row subselects that returned more than one row, execution of the query could cause a server crash. (Bug #24653) * For *Note `ALTER TABLE': alter-table, using `ORDER BY EXPRESSION' could cause a server crash. Now the `ORDER BY' clause permits only column names to be specified as sort criteria (which was the only documented syntax, anyway). (Bug #24562) * Within stored routines or prepared statements, inconsistent results occurred with multiple use of `INSERT ... SELECT ... ON DUPLICATE KEY UPDATE' when the `ON DUPLICATE KEY UPDATE' clause erroneously tried to assign a value to a column mentioned only in its *Note `SELECT': select. part. (Bug #24491) * Expressions of the form `(a, b) IN (SELECT a, MIN(b) FROM t GROUP BY a)' could produce incorrect results when column `a' of table `t' contained `NULL' values while column `b' did not. (Bug #24420) * If a prepared statement accessed a view, access to the tables listed in the query after that view was checked in the security context of the view. (Bug #24404) * A nested query on a partitioned table returned fewer records than on the corresponding nonpartitioned table, when the subquery affected more than one partition. (Bug #24186) * Expressions of the form `(a, b) IN (SELECT c, d ...)' could produce incorrect results if `a', `b', or both were `NULL'. (Bug #24127) * Queries that evaluate `NULL IN (SELECT ... UNION SELECT ...)' could produce an incorrect result (`FALSE' instead of `NULL'). (Bug #24085) * Some *Note `UPDATE': update. statements were slower than in previous versions when the search key could not be converted to a valid value for the type of the search column. (Bug #24035) * `ISNULL(DATE(NULL))' and `ISNULL(CAST(NULL AS DATE))' erroneously returned false. (Bug #23938) * Within a stored routine, accessing a declared routine variable with `PROCEDURE ANALYSE()' caused a server crash. (Bug #23782) * For an `InnoDB' table with any `ON DELETE' trigger, *Note `TRUNCATE TABLE': truncate-table. mapped to *Note `DELETE': delete. and activated triggers. Now a fast truncation occurs and triggers are not activated. . *Important*: As a result of this fix, *Note `TRUNCATE TABLE': truncate-table. now requires the `DROP' privilege rather than the `DELETE' privilege. (Bug #23556) * With `ONLY_FULL_GROUP_BY' enabled, the server was too strict: Some expressions involving only aggregate values were rejected as nonaggregate (for example, `MAX(a)' - `MIN(a)'). (Bug #23417) * The arguments to the `ENCODE()' and the `DECODE()' functions were not printed correctly, causing problems in the output of *Note `EXPLAIN EXTENDED': explain. and in view definitions. (Bug #23409) * Some queries against `INFORMATION_SCHEMA' that used subqueries failed. . (Bug #23299) * `readline' detection did not work correctly on NetBSD. (Bug #23293) * The number of `setsockopt()' calls performed for reads and writes to the network socket was reduced to decrease system call overhead. (Bug #22943) * Storing values specified as hexadecimal values 64 or more bits long in `BIT(64)', *Note `BIGINT': numeric-types, or `BIGINT UNSIGNED' columns did not raise any warning or error if the value was out of range. (Bug #22533) * Type conversion errors during formation of index search conditions were not correctly checked, leading to incorrect query results. (Bug #22344) * For the `IF()' and `COALESCE()' function and `CASE' expressions, large unsigned integer values could be mishandled and result in warnings. (Bug #22026) * Inserting `DEFAULT' into a column with no default value could result in garbage in the column. Now the same result occurs as when inserting `NULL' into a `NOT NULL' column. (Bug #20691) * Indexes disabled with `ALTER TABLE ... DISABLE KEYS' could in some cases be used by specifying `FORCE INDEX'. (Bug #20604) * If a duplicate key value was present in the table, *Note `INSERT ... ON DUPLICATE KEY UPDATE': insert-on-duplicate. reported a row count indicating that a record was updated, even when no record actually changed due to the old and new values being the same. Now it reports a row count of zero. (Bug #19978) See also Bug #27006, Bug #27033, Bug #27210. * `ORDER BY' values of the *Note `DOUBLE': numeric-types. or *Note `DECIMAL': numeric-types. types could change the result returned by a query. (Bug #19690) * The `readline' library wrote to uninitialized memory, causing *Note `mysql': mysql. to crash. (Bug #19474) * Use of already freed memory caused SSL connections to hang forever. (Bug #19209) * The server might fail to use an appropriate index for *Note `DELETE': delete. when `ORDER BY', `LIMIT', and a nonrestricting `WHERE' are present. (Bug #17711) * The optimizer used a filesort rather than a `const' table read in some cases when the latter was possible. (Bug #16590) * To enable installation of MySQL RPMs on Linux systems running RHEL 4 (which includes SE-Linux) additional information was provided to specify some actions that are permitted to the MySQL binaries. (Bug #12676) * `CONNECTION' is no longer treated as a reserved word. (Bug #12204) * The presence of `ORDER BY' in a view definition prevented the `MERGE' algorithm from being used to resolve the view even if nothing else in the definition required the `TEMPTABLE' algorithm. (Bug #12122)  File: manual.info, Node: news-5-1-15, Next: news-5-1-14, Prev: news-5-1-16, Up: news-5-1-x D.1.53 Changes in MySQL 5.1.15 (25 January 2007) ------------------------------------------------ This is a new Beta development release, fixing recently discovered bugs. *Note*: This Beta release, as any other pre-production release, should not be installed on _production_ level systems or systems with critical data. It is good practice to back up your data before installing any new version of software. Although MySQL has worked very hard to ensure a high level of quality, protect your data by making a backup as you would for any software beta release. Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. This section documents all changes and bug fixes that have been applied since the last official MySQL release. If you would like to receive more fine-grained and personalized _update alerts_ about fixes that are relevant to the version and features you use, please consider subscribing to _MySQL Enterprise_ (a commercial MySQL offering). For more details, please see http://www.mysql.com/products/enterprise. *Functionality added or changed:* * *Incompatible Change*: *MySQL Cluster*: The `LockPagesInMainMemory' configuration parameter has changed its type and possible values. *Important*: The values `true' and `false' are no longer accepted for this parameter. If you were using this parameter and had it set to `false' in a previous release, you must change it to `0'. If you had this parameter set to `true', you should instead use `1' to obtain the same behavior as previously, or `2' to take advantage of new functionality introduced with this release, as described in the section cited above. (Bug #25686) * *Incompatible Change*: `InnoDB' rolls back only the last statement on a transaction timeout. A new option, `--innodb_rollback_on_timeout', causes `InnoDB' to abort and roll back the entire transaction if a transaction timeout occurs (the same behavior as in MySQL 5.0.13 and earlier). (Bug #24200) * *Incompatible Change*: Previously, the `DATE_FORMAT()' function returned a binary string. Now it returns a string with a character set and collation given by `character_set_connection' and `collation_connection' so that it can return month and weekday names containing non-ASCII characters. (Bug #22646) * *Incompatible Change*: The following conditions apply to enabling the `read_only' system variable: * If you attempt to enable `read_only' while you have any explicit locks (acquired with *Note `LOCK TABLES': lock-tables. or have a pending transaction, an error will occur. * If other clients hold explicit table locks or have pending transactions, the attempt to enable `read_only' blocks until the locks are released and the transactions end. While the attempt to enable `read_only' is pending, requests by other clients for table locks or to begin transactions also block until `read_only' has been set. * `read_only' can be enabled while you hold a global read lock (acquired with *Note `FLUSH TABLES WITH READ LOCK': flush.) because that does not involve table locks. Previously, the attempt to enable `read_only' would return immediately even if explicit locks or transactions were pending, so some data changes could occur for statements executing in the server at the same time. (Bug #22009, Bug #11733) * *Incompatible Change*: Previously, the `ARCHIVE' storage engine created a metadata file with an extension of `.ARM' for each table. The engine no longer creates this file. * *Important Change*: When using a `MERGE' table, the definition of the table and the underlying `MyISAM' tables are checked each time the tables are opened for access (including any *Note `SELECT': select. or *Note `INSERT': insert. statement). Each table is compared for column order, types, sizes, and associated indexes. If there is a difference in any one of the tables, the statement will fail. * *Important Change*: Previously, duplicate-key errors were indicated by the `ER_DUP_ENTRY' error code (1062). This code is no longer used. Instead, the server returns `ER_DUP_ENTRY_WITH_KEY_NAME' (1582), and the error message indicates the name of the index for which the duplicate occurred. Applications that test for duplicate keys should look for both error codes if they need to be compatible with current and older servers. See also Bug #28842. * *MySQL Cluster*: The *Note `NDB': mysql-cluster. storage engine could leak memory during file operations. (Bug #21858) * *Replication*: Calling a nondeterministic stored routine when using statement-based replication now throws an error. Formerly, defining such a stored routine would cause an error to be thrown. (Bug #16456) * On Unix, when searching the standard locations for option files, MySQL programs now also look for `/etc/mysql/my.cnf' after checking for `/etc/my.cnf' and before checking the remaining locations. (Bug #25104) * The default value of the `max_connections' variable has been increased to 151 in order that Web sites running on Apache and using MySQL will not have more processes trying to access MySQL than the default number of connections available. The maximum number of Apache processes is determined by the Apache `MaxClient' setting, which defaults to 256, but is usually set to 150 in the `httpd.conf' commonly distributed with Apache. For more information about `MaxClient', see `http://httpd.apache.org/docs/2.2/mod/mpm_common.html#maxclients'. (Bug #23883) * The `Com_create_user' status variable was added (for counting *Note `CREATE USER': create-user. statements). (Bug #22958) * The `--memlock' option relies on system calls that are unreliable on some operating systems. If a crash occurs, the server now checks whether `--memlock' was specified and if so issues some information about possible workarounds. (Bug #22860) * The (undocumented) `UNIQUE_USERS()' and `GROUP_UNIQUE_USERS()' functions were removed. (Bug #22687) * Partitioning of tables using the `FEDERATED' storage engine is no longer permitted. Attempting to create such a table or to modify an existing table so that is uses both partitioning and `FEDERATED' now fails with an error. (Bug #22451) * The `--skip-thread-priority' option now is enabled by default for binary Mac OS X distributions. Use of thread priorities degrades performance on Mac OS X. (Bug #18526) * The bundled yaSSL library was upgraded to version 1.5.0. * Remote servers for use with the `FEDERATED' storage engine now can be managed with the new `CREATE/ALTER/DROP SERVER' syntax. * Added the `--disable-grant-options' option to `configure'. If `configure' is run with this option, the `--bootstrap', `--skip-grant-tables', and `--init-file' options for *Note `mysqld': mysqld. are disabled and cannot be used. For Windows, the `configure.js' script recognizes the `DISABLE_GRANT_OPTIONS' flag, which has the same effect. *Bugs fixed:* * *Incompatible Change*: For *Note `ENUM': enum. columns that had enumeration values containing commas, the commas were mapped to `0xff' internally. However, this rendered the commas indistinguishable from true `0xff' characters in the values. This no longer occurs. However, the fix requires that you dump and reload any tables that have *Note `ENUM': enum. columns containing any true `0xff' values. Dump the tables using *Note `mysqldump': mysqldump. with the current server before upgrading from a version of MySQL 5.1 older than 5.1.15 to version 5.1.15 or newer. (Bug #24660) * *Partitioning*: *MySQL Cluster*: Non-32-bit, nonaligned columns were not handled correctly in explicitly partitioned *Note `NDB': mysql-cluster. tables. (Bug #25587) * *MySQL Cluster*: *Replication*: (Replication): Connecting a *Note `mysqld': mysqld. to a cluster where not all nodes were running, starting the remaining cluster nodes, and then disconnecting from the cluster caused the *Note `mysqld': mysqld. process to crash. (Bug #25387) * *MySQL Cluster*: It was not possible to create an *Note `NDB': mysql-cluster. table with a key on two *Note `VARCHAR': char. columns where both columns had a storage length in excess of 256. (Bug #25746) * *MySQL Cluster*: Hosts in clusters with large numbers of nodes could experience excessive CPU usage while obtaining configuration data. (Bug #25711) * *MySQL Cluster*: In some circumstances, shutting down the cluster could cause connected *Note `mysqld': mysqld. processes to crash. (Bug #25668) * *MySQL Cluster*: Some aggregate queries such as `SELECT COUNT(*)' performed a table scan on *Note `NDB': mysql-cluster. tables rather than checking table statistics, causing such queries to perform much more slowly in MySQL Cluster 5.1 than in 5.0. (Bug #25567) * *MySQL Cluster*: Memory allocations for *Note `TEXT': blob. columns were calculated incorrectly, resulting in space being wasted and other issues. (Bug #25562) * *MySQL Cluster*: The failure of a master node during a node restart could lead to a resource leak, causing later node failures. (Bug #25554) * *MySQL Cluster*: The failure of a node during a local checkpoint could lead to other node failures. (Bug #25468) * *MySQL Cluster*: A node shutdown occurred if the master failed during a commit. (Bug #25364) * *MySQL Cluster*: Creating a nonunique index with the `USING HASH' clause silently created an ordered index instead of issuing a warning. (Bug #24820) * *MySQL Cluster*: *Note `ndb_config': mysql-cluster-programs-ndb-config. failed when trying to use 2 management servers and node IDs. (Bug #23887) * *MySQL Cluster*: When a data node was shut down using the management client `STOP' command, a connection event (`NDB_LE_Connected') was logged instead of a disconnection event (`NDB_LE_Disconnected'). (Bug #22773) * *MySQL Cluster*: The management server did not handle logging of node shutdown events correctly in certain cases. (Bug #22013) * *MySQL Cluster*: *Note `SELECT': select. statements with a *Note `BLOB': blob. or *Note `TEXT': blob. column in the selected column list and a `WHERE' condition including a primary key lookup on a *Note `VARCHAR': char. primary key produced empty result sets. (Bug #19956) * *MySQL Cluster*: When stopping and restarting multiple data nodes, the last node to be restarted would sometimes hang in Phase 100. (Bug #19645) * *Replication*: Using row-based replication to replicate to a table having at least one extra *Note `BIT': numeric-types. column with a default value on the slave as compared to the master could cause the slave to fail. (Bug #24490) * *Replication*: When *Note `SET PASSWORD': set-password. was written to the binary log, double quotation marks were included in the statement. If the slave was running in with the server SQL mode set to `ANSI_QUOTES', then the event failed, which halted the replication process. (Bug #24158) * *Replication*: A stored procedure, executed from a connection using a binary character set, and which wrote multibyte data, would write incorrectly escaped entries to the binary log. This caused syntax errors, and caused replication to fail. (Bug #23619, Bug #24492) * *Replication*: Using *Note `CREATE TABLE ... SELECT': create-table. and rolling back the transaction would leave an empty table on the master, but the instructions would not be recorded in the binary log and therefore replicated to the slave. This would result in a difference between the master and slave databases. An implicit commit has been added to ensure consistency. (Bug #22865) * *Replication*: Changes to the `lc_time_names' system variable were not replicated. (Bug #22645) * *Replication*: For *Note `SET': set-option, *Note `SELECT': select, and *Note `DO': do. statements that invoked a stored function from a database other than the default database, the function invocation could fail to be replicated. (Bug #19725) * *Disk Data*: Following three or more missed local checkpoints by a cluster node, a restart of the node caused incorrect undo information to be used for Disk Data tables. (Bug #25636) * *Disk Data*: *Note `MEDIUMTEXT': blob. columns of Disk Data tables were stored in memory rather than on disk, even if the columns were not indexed. (Bug #25001) * *Disk Data*: Performing a node restart with a newly dropped Disk Data table could lead to failure of the node during the restart. (Bug #24917) * *Disk Data*: Changing a column specification or issuing a *Note `TRUNCATE TABLE': truncate-table. statement on a Disk Data table caused the table to become an in-memory table. (Bug #24667, Bug #25296) * *Disk Data*: When restoring from backup a cluster containing any Disk Data tables with hidden primary keys, a node failure resulted which could lead to a crash of the cluster. (Bug #24166) * *Disk Data*: Repeated `CREATE', `DROP', or *Note `TRUNCATE TABLE': truncate-table. in various combinations with system restarts between these operations could lead to the eventual failure of a system restart. (Bug #21948) * *Disk Data*: Extents that should have been available for re-use following a *Note `DROP TABLE': drop-table. operation were not actually made available again until after the cluster had performed a local checkpoint. (Bug #17605) * *Cluster Replication*: Certain errors in replication setups could lead to unexpected node failures. (Bug #25755) * *Cluster Replication*: Connecting an API node to the cluster during a node restart while performing database operations could cause the restarting node to fail. (Bug #25329) * *Cluster Replication*: Following a restart of the master cluster, the latest GCI was set to 0 upon reconnection to the slave. (Bug #21806) * *Cluster API*: Deletion of an `Ndb_cluster_connection' object took a very long time. (Bug #25487) * *Cluster API*: Invoking the `NdbTransaction::execute()' method using execution type `Commit' and abort option `AO_IgnoreError' could lead to a crash of the transaction coordinator (`DBTC'). (Bug #25090) * *Cluster API*: A unique index lookup on a nonexistent tuple could lead to a data node timeout (error 4012). (Bug #25059) * *Cluster API*: When using the `NdbTransaction::execute()' method, a very long timeout (greater than 5 minutes) could result if the last data node being polled was disconnected from the cluster. (Bug #24949) * *Cluster API*: Due to an error in the computation of table fragment arrays, some transactions were not executed from the correct starting point. (Bug #24914) * `mysqltest_embedded' crashed at startup. (Bug #25890) * Referencing an ambiguous column alias in an expression in the `ORDER BY' clause of a query caused the server to crash. (Bug #25427) * A number of issues were uncovered by Valgrind. (Bug #25396) * Using a view in combination with a `USING' clause caused column aliases to be ignored. (Bug #25106) * A multiple-table *Note `DELETE QUICK': delete. could sometimes cause one of the affected tables to become corrupted. (Bug #25048) * An assertion failed incorrectly for prepared statements that contained a single-row uncorrelated subquery that was used as an argument of the `IS NULL' predicate. (Bug #25027) * In the *Note `INFORMATION_SCHEMA.KEY_COLUMN_USAGE': key-column-usage-table. table, the value displayed for the `REFERENCED_TABLE_NAME' column was the table name as encoded for disk storage, not the actual table name. (Bug #25026) * The `REPEAT()' function could return `NULL' when passed a column for the count argument. (Bug #24947) * *Note `mysql_upgrade': mysql-upgrade. failed if the `--password' (or `-p') option was given. (Bug #24896) * Accessing a fixed record format table with a crashed key definition results in server/*Note `myisamchk': myisamchk. segmentation fault. (Bug #24855) * *Note `mysqld_multi': mysqld-multi. and *Note `mysqlaccess': mysqlaccess. looked for option files in `/etc' even if the `--sysconfdir' option for `configure' had been given to specify a different directory. (Bug #24780) * If there was insufficient memory available to *Note `mysqld': mysqld, this could sometimes cause the server to hang during startup. (Bug #24751) * Optimizations that are legal only for subqueries without tables and `WHERE' conditions were applied for any subquery without tables. (Bug #24670) * Under certain rare circumstances, local checkpoints were not performed properly, leading to an inability to restart one or more data nodes. (Bug #24664) * A workaround was implemented to avoid a race condition in the NPTL `pthread_exit()' implementation. (Bug #24507) * Under some circumstances, a `REORGANIZE PARTITION' statement could crash *Note `mysqld': mysqld. (Bug #24502) * `mysqltest' crashed with a stack overflow. (Bug #24498) * Attempts to access a `MyISAM' table with a corrupt column definition caused a server crash. (Bug #24401) * *Note `ALTER TABLE ENABLE KEYS': alter-table. or *Note `ALTER TABLE DISABLE KEYS': alter-table. combined with another *Note `ALTER TABLE': alter-table. option other than `RENAME TO' did nothing. In addition, if *Note `ALTER TABLE': alter-table. was used on a table having disabled keys, the keys of the resulting table were enabled. (Bug #24395) * When opening a corrupted `.frm' file during a query, the server crashes. (Bug #24358) * The `--extern' option for `mysql-test-run.pl' did not function correctly. (Bug #24354) * Some joins in which one of the joined tables was a view could return erroneous results or crash the server. (Bug #24345) * The *Note `mysql.server': mysql-server. script used the `source' command, which is less portable than the `.' command; it now uses `.' instead. (Bug #24294) * A view was not handled correctly if the *Note `SELECT': select. part contained ``\Z''. (Bug #24293) * *Note `mysql_install_db': mysql-install-db. did not create the `mysql.plugin' table if strict SQL mode was enabled. (Bug #24270) * A query using `WHERE UNSIGNED_COLUMN NOT IN ('NEGATIVE_VALUE')' could cause the server to crash. (Bug #24261) * *Note `ALTER TABLE': alter-table. statements that performed both `RENAME TO' and `{ENABLE|DISABLE} KEYS' operations caused a server crash. (Bug #24219) * A *Note `FETCH': fetch. statement using a cursor on a table which was not in the table cache could sometimes cause the server to crash. (Bug #24117) * Hebrew-to-Unicode conversion failed for some characters. Definitions for the following Hebrew characters (as specified by the ISO/IEC 8859-8:1999) were added: LEFT-TO-RIGHT MARK (LRM), RIGHT-TO-LEFT MARK (RLM) (Bug #24037) * On HP-UX, `mysqltest' (nonthread-safe) crashed due to being linked against a thread-safe `libmysys' library. (Bug #23984) * The server was built even when `configure' was run with the `--without-server' option. (Bug #23973) See also Bug #32898. * The MySQL 5.1.12 binaries for Windows were missing the `FEDERATED', `EXAMPLE', and `BLACKHOLE' storage engines. (Bug #23900) * `ROW_COUNT()' did not work properly as an argument to a stored procedure. (Bug #23760) * When reading from the standard input on Windows, *Note `mysqlbinlog': mysqlbinlog. opened the input in text mode rather than binary mode and consequently misinterpreted some characters such as `Control+Z'. (Bug #23735) * *Note `OPTIMIZE TABLE': optimize-table. tried to sort R-tree indexes such as spatial indexes, although this is not possible (see *Note optimize-table::). (Bug #23578) * The row count for `MyISAM' tables was not updated properly, causing *Note `SHOW TABLE STATUS': show-table-status. to report incorrect values. (Bug #23526) * The Instance Manager `DROP INSTANCE' command did not work. (Bug #23476) * User-defined variables could consume excess memory, leading to a crash caused by the exhaustion of resources available to the `MEMORY' storage engine, due to the fact that this engine is used by MySQL for variable storage and intermediate results of `GROUP BY' queries. Where *Note `SET': set-option. had been used, such a condition could instead give rise to the misleading error message `You may only use constant expressions with SET', rather than `Out of memory (Needed NNNNNN bytes)'. (Bug #23443) * A table created with the `ROW_FORMAT = FIXED' table option lost that option if an index was added or dropped with *Note `CREATE INDEX': create-index. or *Note `DROP INDEX': drop-index. (Bug #23404) * A deadlock could occur, with the server hanging on `Closing tables', with a sufficient number of concurrent *Note `INSERT DELAYED': insert-delayed, *Note `FLUSH TABLES': flush, and *Note `ALTER TABLE': alter-table. operations. (Bug #23312) * Accuracy was improved for comparisons between *Note `DECIMAL': numeric-types. columns and numbers represented as strings. (Bug #23260) * The Instance Manager `STOP INSTANCE' command took too much time and caused Instance Manager to be unresponsive. (Bug #23215) * If there was insufficient memory to store or update a blob record in a `MyISAM' table then the table will marked as crashed. (Bug #23196) * A compressed `MyISAM' table that became corrupted could crash *Note `myisamchk': myisamchk. and possibly the MySQL Server. (Bug #23139) * *Note `CREATE TABLE ... SELECT': create-table. statements were not rolled back correctly. As part of the fix, such a statement now causes an implicit commit before and after it is executed. However, it does not cause a commit when used to create a temporary table. (Bug #22864) * *Note `mysql_upgrade': mysql-upgrade. failed when called with a `--basedir' path name containing spaces. (Bug #22801) * Using *Note `INSTALL PLUGIN': install-plugin. followed by a restart of the server caused an error due to memory not being properly initialized. (Bug #22694) * `SET lc_time_names = VALUE ' permitted only exact literal values, not expression values. (Bug #22647) * A partitioned table that used the `DATA DIRECTORY' option, where the data directory was the same as the directory in which the table definition file resided, became corrupted following `ALTER TABLE ENGINE=ARCHIVE'. This was actually due to an issue with the `ARCHIVE' storage engine, and not with partitioned tables in general. (Bug #22634) * The `STDDEV()' function returned a positive value for data sets consisting of a single value. (Bug #22555) * *Note `SHOW COLUMNS': show-columns. reported some `NOT NULL' columns as `NULL'. (Bug #22377) * A server crash occurred when using *Note `LOAD DATA': load-data. to load a table containing a `NOT NULL' spatial column, when the statement did not load the spatial column. Now a `NULL supplied to NOT NULL column' error occurs. (Bug #22372) * An *Note `ALTER TABLE': alter-table. statement that used a `RENAME' clause in combination with a `MODIFY' or `CHANGE' that did not actually change the table (for example, when it changed a column's type from *Note `INT': numeric-types. to *Note `INT': numeric-types.). The behavior caused by this bug differed according to whether or not the storage engine used by the table was transactional or nontransactional. For transactional tables (such as those using the `InnoDB' storage engine), the statement simply failed; for nontransactional tables (such as those using the `MyISAM' storage engine), the *Note `ALTER TABLE': alter-table. statement succeeding renaming the table, but subsequent *Note `SELECT': select. statements against the renamed table would fail. (Bug #22369) * The Instance Manager `STOP INSTANCE' command could not be applied to instances in the `Crashed', `Failed', or `Abandoned' state. (Bug #22306) * `DATE_ADD()' requires complete dates with no `zero' parts, but sometimes did not return `NULL' when given such a date. (Bug #22229) * Some small double precision numbers (such as `1.00000001e-300') that should have been accepted were truncated to zero. (Bug #22129) * Changing the value of `MI_KEY_BLOCK_LENGTH' in `myisam.h' and recompiling MySQL resulted in a *Note `myisamchk': myisamchk. that saw existing `MyISAM' tables as corrupt. (Bug #22119) * For a nonexistent table, `DROP TEMPORARY TABLE' failed with an incorrect error message if `read_only' was enabled. (Bug #22077) * A crash of the MySQL Server could occur when unpacking a *Note `BLOB': blob. column from a row in a corrupted MyISAM table. This could happen when trying to repair a table using either *Note `REPAIR TABLE': repair-table. or *Note `myisamchk': myisamchk.; it could also happen when trying to access such a `broken' row using statements like *Note `SELECT': select. if the table was not marked as crashed. (Bug #22053) * The code for generating *Note `USE': use. statements for binary logging of *Note `CREATE PROCEDURE': create-procedure. statements resulted in confusing output from *Note `mysqlbinlog': mysqlbinlog. for *Note `DROP PROCEDURE': drop-procedure. statements. (Bug #22043) * `STR_TO_DATE()' returned `NULL' if the format string contained a space following a nonformat character. (Bug #22029) * It was possible to use *Note `DATETIME': datetime. values whose year, month, and day parts were all zeros but whose hour, minute, and second parts contained nonzero values, an example of such an illegal *Note `DATETIME': datetime. being `'0000-00-00 11:23:45''. *Note*: This fix was reverted in MySQL 5.1.18. (Bug #21789) See also Bug #25301. * SSL connections could hang at connection shutdown. (Bug #21781, Bug #24148) * yaSSL crashed on pre-Pentium Intel CPUs. (Bug #21765) * Using *Note `FLUSH TABLES': flush. in one connection while another connection is using *Note `HANDLER': handler. statements caused a server crash. *Note*: This fix was reverted in MySQL 5.1.22 (Bug #21587) See also Bug #29474. * The `FEDERATED' storage engine did not support the `euckr' character set. (Bug #21556) * `InnoDB' crashed while performing XA recovery of prepared transactions. (Bug #21468) * It was possible to set the backslash character (``\'') as the delimiter character using `DELIMITER', but not actually possible to use it as the delimiter. (Bug #21412) * Using *Note `ALTER TABLE': alter-table. to convert a `CSV' table containing `NULL' values to `MyISAM' resulted in warnings. (Bug #21328) * When updating a table that used a `JOIN' of the table itself (for example, when building trees) and the table was modified on one side of the expression, the table would either be reported as crashed or the wrong rows in the table would be updated. (Bug #21310) * `mysqld_error.h' was not installed when only the client libraries were built. (Bug #21265) * `InnoDB': During a restart of the MySQL Server that followed the creation of a temporary table using the `InnoDB' storage engine, MySQL failed to clean up in such a way that `InnoDB' still attempted to find the files associated with such tables. (Bug #20867) * Selecting into variables sometimes returned incorrect wrong results. (Bug #20836) * Queries of the form `SELECT ... WHERE STRING = ANY(...)' failed when the server used a single-byte character set and the client used a multi-byte character set. (Bug #20835) See also Bug #34760. * `mysql_fix_privilege_tables.sql' altered the `table_privs.table_priv' column to contain too few privileges, causing loss of the *Note `CREATE VIEW': create-view. and `SHOW VIEW' privileges. (Bug #20589) * A stored routine containing semicolon in its body could not be reloaded from a dump of a binary log. (Bug #20396) * *Note `SELECT ... FOR UPDATE': select, *Note `SELECT ... LOCK IN SHARE MODE': select, *Note `DELETE': delete, and *Note `UPDATE': update. statements executed using a full table scan were not releasing locks on rows that did not satisfy the `WHERE' condition. (Bug #20390) * The `BUILD/check-cpu' script did not recognize Celeron processors. (Bug #20061) * Unsigned *Note `BIGINT': numeric-types. values treated as signed values by the `MOD()' function. (Bug #19955) * Compiling PHP 5.1 with the MySQL static libraries failed on some versions of Linux. (Bug #19817) * The `DELIMITER' statement did not work correctly when used in an SQL file run using the `SOURCE' statement. (Bug #19799) * `mysqltest' incorrectly tried to retrieve result sets for some queries where no result set was available. (Bug #19410) * *Note `VARBINARY': binary-varbinary. column values inserted on a MySQL 4.1 server had trailing zeros following upgrade to MySQL 5.0 or later. (Bug #19371) * Some *Note `CASE': case-statement. statements inside stored routines could lead to excessive resource usage or a crash of the server. (Bug #19194, Bug #24854) * Instance Manager could crash during shutdown. (Bug #19044) * *Note `myisampack': myisampack. wrote to unallocated memory, causing a crash. (Bug #17951) * *Note `FLUSH LOGS': flush. or *Note `mysqladmin flush-logs': mysqladmin. caused a server crash if the binary log was not open. (Bug #17733) * *Note `mysql_fix_privilege_tables': mysql-fix-privilege-tables. did not accept a password containing embedded space or apostrophe characters. (Bug #17700) * No warning was issued for use of the `DATA DIRECTORY' or `INDEX DIRECTORY' table options on a platform that does not support them. (Bug #17498) * The `FEDERATED' storage engine did not support the `utf8' character set. (Bug #17044) * The optimizer removes expressions from `GROUP BY' and `DISTINCT' clauses if they happen to participate in ` EXPRESSION = CONSTANT' predicates of the `WHERE' clause, the idea being that, if the expression is equal to a constant, then it cannot take on multiple values. However, for predicates where the expression and the constant item are of different result types (for example, when a string column is compared to 0), this is not valid, and can lead to invalid results in such cases. The optimizer now performs an additional check of the result types of the expression and the constant; if their types differ, then the expression is not removed from the `GROUP BY' list. (Bug #15881) * When a prepared statement failed during the prepare operation, the error code was not cleared when it was reused, even if the subsequent use was successful. (Bug #15518) * Dropping a user-defined function sometimes did not remove the UDF entry from the `mysql.proc' table. (Bug #15439) * Inserting a row into a table without specifying a value for a `BINARY(N) NOT NULL' column caused the column to be set to spaces, not zeros. (Bug #14171) * On Windows, the `SLEEP()' function could sleep too long, especially after a change to the system clock. (Bug #14094, Bug #24686, Bug #17635) * *Note `mysqldump --order-by-primary': mysqldump. failed if the primary key name was an identifier that required quoting. (Bug #13926) * Subqueries of the form `NULL IN (SELECT ...)' returned invalid results. (Bug #8804, Bug #23485)  File: manual.info, Node: news-5-1-14, Next: news-5-1-13, Prev: news-5-1-15, Up: news-5-1-x D.1.54 Changes in MySQL 5.1.14 (05 December 2006) ------------------------------------------------- This is a new Beta development release, fixing recently discovered bugs. *Note*: This Beta release, as any other pre-production release, should not be installed on _production_ level systems or systems with critical data. It is good practice to back up your data before installing any new version of software. Although MySQL has worked very hard to ensure a high level of quality, protect your data by making a backup as you would for any software beta release. Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. This section documents all changes and bug fixes that have been applied since the last official MySQL release. If you would like to receive more fine-grained and personalized _update alerts_ about fixes that are relevant to the version and features you use, please consider subscribing to _MySQL Enterprise_ (a commercial MySQL offering). For more details, please see http://www.mysql.com/products/enterprise. *Functionality added or changed:* * *Cluster Replication*: *Incompatible Change*: Two major changes have taken place with regard to the MySQL Cluster system tables. These are: 1. The `cluster' database is no longer used. The tables formerly found in the `cluster' database are now in the `mysql' database, and have been renamed as `ndb_binlog_index', `ndb_apply_status', and `ndb_schema'. 2. The `mysql.ndb_apply_status' and `mysql.ndb_schema' tables (formerly `cluster.apply_status' and `cluster.schema' are now created by *Note `ndb_restore': mysql-cluster-programs-ndb-restore, in the event that they do not already exist on the slave cluster. *Note*: When upgrading from versions of MySQL previous to 5.1.14 to 5.1.14 or later, `mysql_fix_privilege_tables' merely creates a new `mysql.ndb_binlog_index' table, but does not remove the existing `cluster' database (or, if upgrading from MySQL 5.1.7 or earlier, the existing `cluster_replication' database), nor any of the tables in it. For more information, see *Note mysql-cluster-replication-schema::. (Bug #14612) * *Cluster Replication*: *Incompatible Change*: The `cluster' database is no longer used. The tables formerly found in the `cluster' database are now in the `mysql' database, and have been renamed as `ndb_binlog_index', `ndb_apply_status', and `ndb_schema'. * *Incompatible Change*: The `prepared_stmt_count' system variable has been converted to the `Prepared_stmt_count' global status variable (viewable with the *Note `SHOW GLOBAL STATUS': show-status. statement). (Bug #23159) * *Incompatible Change*: Previously, you could create a user-defined function (UDF) or stored function with the same name as a built-in function, but could not invoke the UDF. Now an error occurs if you try to create such a UDF. The server also now generates a warning if you create a stored function with the same name as a built-in function. It is not considered an error to create a stored function with the same name as a built-in function because you can invoke the function using ` DB_NAME.FUNC_NAME()' syntax. However, the server now generates a warning in this case. See *Note function-resolution::, for the rules describing how the server interprets references to different kinds of functions. (Bug #22619, Bug #18239) * *Disk Data*: *Important Change*: The output of *Note `mysqldump': mysqldump. now includes by default all tablespace and logfile group definitions used by any tables or databases that are dumped. This fix also introduces the `--no-tablespaces' option (short form: `-y') for *Note `mysqldump': mysqldump, which has the effect of suppressing all *Note `CREATE LOGFILE GROUP': create-logfile-group. and *Note `CREATE TABLESPACE': create-tablespace. statements in the output. *Note*: The working of the `--all-tablespaces' or `-Y' option for *Note `mysqldump': mysqldump. remains unaffected by this change. (Bug #20839) * *MySQL Cluster*: Backup messages are now printed to the Cluster log. (Bug #24544) * *MySQL Cluster*: Setting the configuration parameter `LockPagesInMainMemory' had no effect. (Bug #24461) * *MySQL Cluster*: The error message `Management server closed connection', when recorded in the MySQL error log, now includes a timestamp indicating when the error took place. (Bug #21519) * *MySQL Cluster*: It is now possible to create a unique hashed index on a column that is not defined as `NOT NULL'. *Note*: This change applies only to tables using the *Note `NDB': mysql-cluster. storage engine. Unique indexes on columns in *Note `NDB': mysql-cluster. tables do not store null values because they are mapped to primary keys in an internal index table (and primary keys cannot contain nulls). Normally, an additional ordered index is created when one creates unique indexes on *Note `NDB': mysql-cluster. table columns; this can be used to search for `NULL' values. However, if `USING HASH' is specified when such an index is created, no ordered index is created. The reason for permitting unique hash indexes with null values is that, in some cases, the user wants to save space if a large number of records are pre-allocated but not fully initialized. This also assumes that the user will _not_ try to search for null values. Since MySQL does not support indexes that are not permitted to be searched in some cases, the *Note `NDB': mysql-cluster. storage engine uses a full table scan with pushed conditions for the referenced index columns to return the correct result. A warning is returned if one creates a unique nullable hash index, since the query optimizer should be provided a hint not to use it with `NULL' values if this can be avoided. (Bug #21507) * *Note `DROP TRIGGER': drop-trigger. now supports an `IF EXISTS' clause. (Bug #23703) * Direct and indirect usage of stored routines, user-defined functions, and table references is now prohibited in *Note `CREATE EVENT': create-event. and *Note `ALTER EVENT': alter-event. statements. See *Note create-event::, and *Note alter-event::, for more specific information. (Bug #22830) * The XPath operators `<' and `>', as implemented in the `ExtractValue()' function, operated in reverse. With this fix, all standard XPath comparison operators should now be supported correctly for use with the `ExtractValue()' and `UpdateXML()' functions. (Bug #22823) * For the *Note `mysql': mysql. client, display of result set metadata now is enabled with the `--column-type-info' option rather than with `--debug-info'/`-T'. * *Note `mysqladmin': mysqladmin, *Note `mysqlcheck': mysqlcheck, *Note `mysqldump': mysqldump, *Note `mysqlimport': mysqlimport, and *Note `mysqlshow': mysqlshow. now accept the `--debug-info' option, which displays debugging information and memory and CPU usage statistics at program exit. *Bugs fixed:* * *Performance*: Evaluation of subqueries that require the filesort algorithm were allocating and freeing the `sort_buffer_size' buffer many times, resulting in slow performance. Now the buffer is allocated once and reused. (Bug #21727) * *MySQL Cluster*: *Replication*: (Replication): If errors occurred during purging of the binary logs, extraneous rows could remain left in the `binlog_index' table. (Bug #15021) * *MySQL Cluster*: The failure of a data node failure during a schema operation could lead to additional node failures. (Bug #24752) * *MySQL Cluster*: A committed read could be attempted before a data node had time to connect, causing a timeout error. (Bug #24717) * *MySQL Cluster*: The simultaneous shutdown of *Note `mysqld': mysqld. and *Note `ndbd': mysql-cluster-programs-ndbd. processes caused unnecessary locking. (Bug #24655) * *MySQL Cluster*: The failure of the master node in a node group during the allocation of node IDs could cause *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. to hang. (Bug #24543) * *MySQL Cluster*: In certain rare cases, a data node could crash due to a typographical error in the MySQL Cluster source code. (Bug #24476) * *MySQL Cluster*: Creating a new tables containing a *Note `BLOB': blob. column when the server was short of memory could cause the server to crash. (Bug #24470) * *MySQL Cluster*: Sudden disconnection of an SQL or data node could lead to shutdown of data nodes with the error `failed ndbrequire'. (Bug #24447) * *MySQL Cluster*: Any statement following the execution of *Note `CREATE TABLE ... LIKE NDB_TABLE': create-table. (where NDB_TABLE was a table using the *Note `NDB': mysql-cluster. storage engine), would cause the *Note `mysql': mysql. client to hang. (Bug #24301) * *MySQL Cluster*: (Disk Data): Excessive fragmentation of Disk Data files (including log files and data files) could occur during the course of normal use. (Bug #24143) * *MySQL Cluster*: When the management client command `ALL RESTART -i' was executed while one data node was not running, all data nodes in the cluster were shut down. (Bug #24105) * *MySQL Cluster*: A query using an index scan followed by a delete operation, and then a rollback could cause one or more data nodes to crash. (Bug #24039) * *MySQL Cluster*: (Disk Data): Under some circumstances, a *Note `DELETE': delete. from a Disk Data table could cause *Note `mysqld': mysqld. to crash. (Bug #23542) * *MySQL Cluster*: It was possible for the sum of the `MaxNoOfTables', `MaxNoOfOrderedIndexes', and `MaxNoOfUniqueHashIndexes' configuration parameters, plus the number of system tables to exceed the maximum value for a `Uint32' number. In such a case, the cluster's data nodes failed to start, and no reason for this could easily be determined from the error messages provided. (Bug #22548) * *MySQL Cluster*: A value equal to or greater than the permitted maximum for `LongMessageBuffer' caused all data nodes to crash. (Bug #22547) * *MySQL Cluster*: Multiple occurrences of error conditions were logged with duplicat error messages rather than being reported with a single error message stating that the error was encountered N times. (Bug #22313) * *MySQL Cluster*: Given a table `mytbl' in a database `mydb' on a MySQL Server acting as an SQL node in a MySQL Cluster, then, following multiple `ALTER TABLE mytbl ENGINE=ENGINE' statements--first, to change the storage engine used for a table to *Note `NDB': mysql-cluster, and then again to change the table to use a non-*Note `NDB': mysql-cluster. storage engine--a `DROP DATABASE mydb' statement executed on any SQL node in the cluster would cause `mydb' to be dropped on _all_ SQL nodes in the cluster, even if `mydb' contained non-*Note `NDB': mysql-cluster. tables. (Bug #21495) * *MySQL Cluster*: An incorrect error message was displayed in the event that the value of the `MaxNoOfOrderedIndexes' parameter was set too low. (Bug #20065) * *MySQL Cluster*: An incorrect error message was displayed in the event that the value of the `DataMemory' parameter was insufficient for the amount of data to be stored by the cluster. (Bug #19808) * *MySQL Cluster*: Some values of `MaxNoOfTriggers' could cause the server to become inaccessible following startup of the data nodes. (Bug #19454) * *MySQL Cluster*: If the value set for `MaxNoOfAttributes' is excessive, a suitable error message is now returned. (Bug #19352) * *MySQL Cluster*: Different error messages were returned for similar cases involving failure to allocate memory for Cluster operations. (Bug #19203) * *MySQL Cluster*: A unique constraint violation was not ignored by an `UPDATE IGNORE' statement when the constraint violation occurred on a nonprimary key. (Bug #18487, Bug #24303) * *Replication*: With row-based binary logging, replicated multiple-statement transaction deadlocks did not return the correct error code, causing the slave SQL thread to stop rather than roll back and re-execute. (Bug #23831) * *Replication*: Changes to character set variables prior to an action on a replication-ignored table were forgotten by slave servers. (Bug #22877) * *Replication*: On slave servers, transactions that exceeded the lock wait timeout failed to roll back properly. (Bug #20697) * *Replication*: SQL statements close to the size of `max_allowed_packet' could produce binary log events larger than `max_allowed_packet' that could not be read by slave servers. (Bug #19402) * *Disk Data*: *Note `ndb_restore': mysql-cluster-programs-ndb-restore. sometimes failed when attempting to restore Disk Data tables due to data node failure caused by accessing uninitialized memory. (Bug #24331) * *Disk Data*: It was possible to execute a statement for creating a Disk Data table that referred to a nonexistent tablespace, in which case the table created was actually an in-memory *Note `NDB': mysql-cluster. table. Such a statement now fails instead, with an appropriate error message. (Bug #23576) * *Cluster API*: Using *Note `BIT': numeric-types. values with any of the comparison methods of the `NdbScanFilter' class caused data nodes to fail. (Bug #24503) * *Cluster API*: Some MGM API function calls could yield incorrect return values in certain cases where the cluster was operating under a very high load, or experienced timeouts in inter-node communications. (Bug #24011) * In some cases, a function that should be parsed as a user-defined function was parsed as a stored function. (Bug #24736) * Some unnecessary Valgrind warnings were removed from the server. (Bug #24488, Bug #24533) * The server source code had multiple exportable definitions of the `field_in_record_is_null()' function. These are now all declared `static'. (Bug #24190) * The loose index scan optimization for `GROUP BY' with `MIN' or `MAX' was not applied within other queries, such as *Note `CREATE TABLE ... SELECT ...': create-table, `INSERT ... SELECT ...', or in the `FROM' clauses of subqueries. (Bug #24156) * Subqueries for which a pushed-down condition did not produce exactly one key field could cause a server crash. (Bug #24056) * The size of `MEMORY' tables and internal temporary tables was limited to 4GB on 64-bit Windows systems. (Bug #24052) * `LAST_DAY('0000-00-00')' could cause a server crash. (Bug #23653) * A trigger that invoked a stored function could cause a server crash when activated by different client connections. (Bug #23651) * The stack size for NetWare binaries was increased to 128KB to prevent problems caused by insufficient stack size. (Bug #23504) * If elements in a nontop-level `IN' subquery were accessed by an index and the subquery result set included a `NULL' value, the quantified predicate that contained the subquery was evaluated to `NULL' when it should return a non-`NULL' value. (Bug #23478) * When applying the `group_concat_max_len' limit, `GROUP_CONCAT()' could truncate multi-byte characters in the middle. (Bug #23451) * *Note `mysql_affected_rows()': mysql-affected-rows. could return values different from *Note `mysql_stmt_affected_rows()': mysql-stmt-affected-rows. for the same sequence of statements. (Bug #23383) * Calculation of `COUNT(DISTINCT)', `AVG(DISTINCT)', or `SUM(DISTINCT)' when they are referenced more than once in a single query with `GROUP BY' could cause a server crash. (Bug #23184) * With row-based binary logging, for *Note `CREATE TABLE IF NOT EXISTS LIKE TEMPORARY_TABLE ': create-table. statements, the `IF NOT EXISTS' clause was not logged. (Bug #22762) * `BENCHMARK()', `ENCODE()', `DECODE()', and `FORMAT()' could only accept a constant for some parameters, and could not be used in prepared statements. (Bug #22684) * Queries using a column alias in an expression as part of an `ORDER BY' clause failed, an example of such a query being `SELECT mycol + 1 AS mynum FROM mytable ORDER BY 30 - mynum'. (Bug #22457) * Using *Note `EXPLAIN': explain. caused a server crash for queries that selected from `INFORMATION_SCHEMA' in a subquery in the `FROM' clause. (Bug #22413) * Instance Manager option-parsing code caused memory-allocation errors. (Bug #22242) * Trailing spaces were not removed from Unicode *Note `CHAR': char. column values when used in indexes. This resulted in excessive usage of storage space, and could affect the results of some `ORDER BY' queries that made use of such indexes. *Note*: When upgrading, it is necessary to re-create any existing indexes on Unicode *Note `CHAR': char. columns of each affected table to take advantage of the fix. See *Note rebuilding-tables::. (Bug #22052) * With row-based binary logging, *Note `CREATE TABLE IF NOT EXISTS SELECT': create-table-select. statements were not logged properly. (Bug #22027) * In some cases, the parser failed to distinguish a user-defined function from a stored function. (Bug #21809) * Inserting a default or invalid value into a spatial column could fail with `Unknown error' rather than a more appropriate error. (Bug #21790) * Through the C API, the member strings in `MYSQL_FIELD' for a query that contained expressions could return incorrect results. (Bug #21635) * View columns were always handled as having implicit derivation, leading to `illegal mix of collation errors' for some views in *Note `UNION': union. operations. Now view column derivation comes from the original expression given in the view definition. (Bug #21505) * `INET_ATON()' returned a signed *Note `BIGINT': numeric-types. value, not an unsigned value. (Bug #21466) * For debug builds, *Note `mysqladmin shutdown': mysqladmin. displayed an extraneous `skipped 9 bytes from file: socket (3)' message. (Bug #21428) * For renaming of views, encoding of table name to file names was not performed. (Bug #21370) * `CREATE FUNCTION X()' and `CREATE FUNCTION Y()' failed with a syntax error instead of warning the user that these function names are already used (for GIS functions). (Bug #21025) * `CONCURRENT' did not work correctly for *Note `LOAD DATA INFILE': load-data. (Bug #20637) * With `lower_case_table_names' set to 1, *Note `SHOW CREATE TABLE': show-create-table. printed incorrect output for table names containing Turkish I (LATIN CAPITAL LETTER I WITH DOT ABOVE). (Bug #20404) * A query with a subquery that references columns of a view from the outer *Note `SELECT': select. could return an incorrect result if used from a prepared statement. (Bug #20327) * For queries that select from a view, the server returned `MYSQL_FIELD' metadata inconsistently for view names and table names. For view columns, the server now returns the view name in the `table' field and, if the column selects from an underlying table, the table name in the `org_table' field. (Bug #20191) * Invalidating the query cache caused a server crash for *Note `INSERT INTO ... SELECT': insert-select. statements that selected from a view. (Bug #20045) * For a cast of a *Note `DATETIME': datetime. value containing microseconds to *Note `DECIMAL': numeric-types, the microseconds part was truncated without generating a warning. Now the microseconds part is preserved. (Bug #19491) * The server could send incorrect column count information to the client for queries that produce a larger number of columns than can fit in a two-byte number. (Bug #19216) * For some problems relating to character set conversion or incorrect string values for *Note `INSERT': insert. or *Note `UPDATE': update, the server reported truncation or length errors instead. (Bug #18908) * Constant expressions and some numeric constants used as input parameters to user-defined functions were not treated as constants. (Bug #18761) * Attempting to use a view containing `DEFINER' information for a nonexistent user resulted in an error message that revealed the definer account. Now the definer is revealed only to users that have the `SUPER' privilege. Other users receive only an `access denied' message. (Bug #17254) * `IN()' and `CHAR()' can return `NULL', but did not signal that to the query processor, causing incorrect results for `IS NULL' operations. (Bug #17047) * Warnings were generated when explicitly casting a character to a number (for example, `CAST('x' AS SIGNED)'), but not for implicit conversions in simple arithmetic operations (such as `'x' + 0'). Now warnings are generated in all cases. (Bug #11927) * Metadata for columns calculated from scalar subqueries was limited to integer, double, or string, even if the actual type of the column was different. (Bug #11032)  File: manual.info, Node: news-5-1-13, Next: news-5-1-12, Prev: news-5-1-14, Up: news-5-1-x D.1.55 Changes in MySQL 5.1.13 (Not released) --------------------------------------------- This is a new Beta development release, fixing recently discovered bugs. *Note*: This Beta release, as any other pre-production release, should not be installed on _production_ level systems or systems with critical data. It is good practice to back up your data before installing any new version of software. Although MySQL has worked very hard to ensure a high level of quality, protect your data by making a backup as you would for any software beta release. Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. This section documents all changes and bug fixes that have been applied since the last official MySQL release. If you would like to receive more fine-grained and personalized _update alerts_ about fixes that are relevant to the version and features you use, please consider subscribing to _MySQL Enterprise_ (a commercial MySQL offering). For more details, please see http://www.mysql.com/products/enterprise. *Functionality added or changed:* * *Incompatible Change*: The number of function names affected by `IGNORE_SPACE' was reduced significantly in MySQL 5.1.13, from about 200 to about 30. (For details about `IGNORE_SPACE', see *Note function-resolution::.) This change improves the consistency of parser operation. However, it also introduces the possibility of incompatibility for old SQL code that relies on the following conditions: * `IGNORE_SPACE' is disabled. * The presence or absence of whitespace following a function name is used to distinguish between a built-in function and stored function that have the same name (for example, `PI()' versus `PI ()'). For functions that are no longer affected by `IGNORE_SPACE' as of MySQL 5.1.13, that strategy no longer works. Either of the following approaches can be used if you have code that is subject to the preceding incompatibility: * If a stored function has a name that conflicts with a built-in function, refer to the stored function with a schema name qualifier, regardless of whether whitespace is present. For example, write ` SCHEMA_NAME.PI()' or `SCHEMA_NAME.PI ()'. * Alternatively, rename the stored function to use a nonconflicting name and change invocations of the function to use the new name. (Bug #21114) * *Incompatible Change*: The `innodb_buffer_pool_awe_mem_mb' system variable has been removed and should no longer be used. * *MySQL Cluster*: A change in the interfaces for the *Note `INFORMATION_SCHEMA.FILES': files-table. table has made the table accessible to storage engines other than *Note `NDB': mysql-cluster. (Bug #23013) * Binary distributions of MySQL 5.1.12 were built without support for partitioning. This has been corrected except for NetWare. (Bug #23949) * If the user specified the server options `--max-connections=N ' or `--table-open-cache=M ', a warning would be given in some cases that some values were recalculated, with the result that `--table-open-cache' could be assigned greater value. In such cases, both the warning and the increase in the `--table-open-cache' value were completely harmless. Note also that it is not possible for the MySQL Server to predict or to control limitations on the maximum number of open files, since this is determined by the operating system. The value of `--table-open-cache' is no longer increased automatically, and a warning is now given only if some values had to be decreased due to operating system limits. (Bug #21915) * For the *Note `CALL': call. statement, stored procedures that take no arguments now can be invoked without parentheses. That is, `CALL p()' and `CALL p' are equivalent. (Bug #21462) * `mysql_upgrade' now passes all the parameters specified on the command line to both `mysqlcheck' and `mysql' using the `upgrade_defaults' file. (Bug #20100) * *Note `mysqldump --single-transaction': mysqldump. now uses `START TRANSACTION /*!40100 WITH CONSISTENT SNAPSHOT */' rather than *Note `BEGIN': commit. to start a transaction, so that a consistent snapshot will be used on those servers that support it. (Bug #19660) *Bugs fixed:* * *Performance*: `InnoDB' showed substandard performance with multiple queries running concurrently. (Bug #15815) * *Important Change*: When installing MySQL on AIX 5.3, you must upgrade AIX to technology level 7 (5300-07) to ensure the required thread libraries are available. * *MySQL Cluster*: Backup of a cluster failed if there were any tables with 128 or more columns. (Bug #23502) * *MySQL Cluster*: Cluster backups failed when there were more than 2048 schema objects in the cluster. (Bug #23499) * *MySQL Cluster*: Restoring a cluster failed if there were any tables with 128 or more columns. (Bug #23494) * *MySQL Cluster*: The management client command `ALL DUMP 1000' would cause the cluster to crash if data nodes were connected to the cluster but not yet fully started. (Bug #23203) * *MySQL Cluster*: *Note `INSERT ... ON DUPLICATE KEY UPDATE': insert-on-duplicate. on an *Note `NDB': mysql-cluster. table could lead to deadlocks and memory leaks. (Bug #23200) * *MySQL Cluster*: An *Note `NDB': mysql-cluster. source file included a `memset()' call with reversed arguments. (Bug #23169) * *MySQL Cluster*: If a node restart could not be performed from the REDO log, no node takeover took place. This could cause partitions to be left empty during a system restart. (Bug #22893) * *MySQL Cluster*: Multiple node restarts in rapid succession could cause a system restart to fail , or induce a race condition. (Bug #22892, Bug #23210) * *MySQL Cluster*: Attempting to create a unique constraint with `USING HASH' on an *Note `NDB': mysql-cluster. table caused *Note `mysqld': mysqld. to crash. (Bug #21873) * *MySQL Cluster*: When inserting a row into an *Note `NDB': mysql-cluster. table with a duplicate value for a nonprimary unique key, the error issued would reference the wrong key. (Bug #21072) * *MySQL Cluster*: Aborting a cluster backup too soon after starting it caused a forced shutdown of the data nodes. (Bug #19148) * *Replication*: Column names were not quoted properly for replicated views. (Bug #19736) * *Replication*: Transient errors in replication from master to slave may trigger multiple `Got fatal error 1236: 'binlog truncated in the middle of event'' errors on the slave. (Bug #4053) * *Disk Data*: In the event of an aborted multiple update, the space in the Disk Data log buffer to be freed as a result was actually freed twice, which could eventually lead to a crash. (Bug #23430) * *Cluster API*: When multiple processes or threads in parallel performed the same ordered scan with exclusive lock and updated the retrieved records, the scan could skip some records, which as a result were not updated. (Bug #20446) * `FORMAT(X,D)' did not accept a nonconstant value for D. (Bug #48374) * There was a race condition in the `InnoDB' `fil_flush_file_spaces()' function. (Bug #24098) * yaSSL-related memory leaks were detected by Valgrind. (Bug #23981) * MySQL 5.0.26 introduced an ABI incompatibility, which this release reverts. Programs compiled against 5.0.26 are not compatible with any other version and must be recompiled. (Bug #23427) * `M % 0' returns `NULL', but (` M % 0) IS NULL' evaluated to false. (Bug #23411) * For not-yet-authenticated connections, the `Time' column in *Note `SHOW PROCESSLIST': show-processlist. was a random value rather than `NULL'. (Bug #23379) * `InnoDB' crashed when trying to display an error message about a foreign key constraint violation when the two tables are in different schemas. (Bug #23368) * MySQL failed to build on Linux/Alpha. (Bug #23256) This regression was introduced by Bug #21250. * If `COMPRESS()' returned `NULL', subsequent invocations of `COMPRESS()' within a result set or within a trigger also returned `NULL'. (Bug #23254) * Insufficient memory (`myisam_sort_buffer_size') could cause a server crash for several operations on `MyISAM' tables: repair table, create index by sort, repair by sort, parallel repair, bulk insert. (Bug #23175) * The column default value in the output from *Note `SHOW COLUMNS': show-columns. or `SELECT FROM INFORMATION_SCHEMA.COLUMNS' was truncated to 64 characters. (Bug #23037) * *Note `mysql': mysql. did not check for errors when fetching data during result set printing. (Bug #22913) * The return value from `my_seek()' was ignored. (Bug #22828) * Use of `SQL_BIG_RESULT' did not influence the sort plan for query execution. (Bug #22781) * The optimizer failed to use equality propagation for `BETWEEN' and `IN' predicates with string arguments. (Bug #22753) * The `Handler_rollback' status variable sometimes was incremented when no rollback had taken place. (Bug #22728) * The `Host' column in *Note `SHOW PROCESSLIST': show-processlist. output was blank when the server was started with the `--skip-grant-tables' option. (Bug #22723) * If a table contains an `AUTO_INCREMENT' column, inserting into an insertable view on the table that does not include the `AUTO_INCREMENT' column should not change the value of `LAST_INSERT_ID()', because the side effects of inserting default values into columns not part of the view should not be visible. MySQL was incorrectly setting `LAST_INSERT_ID()' to zero. (Bug #22584) * The optimizer used the `ref' join type rather than `eq_ref' for a simple join on strings. (Bug #22367) * Some queries that used `MAX()' and `GROUP BY' could incorrectly return an empty result. (Bug #22342) * If an `init_connect' SQL statement produced an error, the connection was silently terminated with no error message. Now the server writes a warning to the error log. (Bug #22158) * An unhandled `NULL' pointer caused a server crash. (Bug #22138) * Incorrect warnings occurred for use of *Note `CREATE TABLE ... LIKE': create-table. or *Note `REPAIR TABLE': repair-table. with the log tables. (Bug #21966) * The optimizer sometimes mishandled R-tree indexes for `GEOMETRY' data types, resulting in a server crash. (Bug #21888) * Use of a DES-encrypted SSL certificate file caused a server crash. (Bug #21868) * Use of *Note `PREPARE': prepare. with a *Note `CREATE PROCEDURE': create-procedure. statement that contained a syntax error caused a server crash. (Bug #21856) * Adding a day, month, or year interval to a *Note `DATE': datetime. value produced a *Note `DATE': datetime, but adding a week interval produced a *Note `DATETIME': datetime. value. Now all produce a *Note `DATE': datetime. value. (Bug #21811) * Use of a subquery that invoked a function in the column list of the outer query resulted in a memory leak. (Bug #21798) * It was not possible to do an atomic rename of the log tables without the possibility of losing rows. Now you can do this: USE mysql; CREATE TABLE IF NOT EXISTS general_log2 LIKE general_log; RENAME TABLE general_log TO general_log_backup, general_log2 TO general_log; (Bug #21785, Bug #17544) * Within a prepared statement, `SELECT (COUNT(*) = 1)' (or similar use of other aggregate functions) did not return the correct result for statement re-execution. (Bug #21354) * Within a stored routine, a view definition cannot refer to routine parameters or local variables. However, an error did not occur until the routine was called. Now it occurs during parsing of the routine creation statement. *Note*: A side effect of this fix is that if you have already created such routines, and error will occur if you execute *Note `SHOW CREATE PROCEDURE': show-create-procedure. or *Note `SHOW CREATE FUNCTION': show-create-function. You should drop these routines because they are erroneous. (Bug #20953) * In *Note `mysql': mysql, invoking `connect' or `\r' with very long DB_NAME or HOST_NAME parameters caused buffer overflow. (Bug #20894) * `WITH ROLLUP' could group unequal values. (Bug #20825) * Range searches on columns with an index prefix could miss records. (Bug #20732) * The server did not allocate sufficient memory for some queries for which a `DISTINCT' to `GROUP BY' conversion is possible and an `ORDER BY' clause is present, resulting in a server crash. (Bug #20503) * `LIKE' searches failed for indexed `utf8' character columns. (Bug #20471) * With `sql_mode = TRADITIONAL', MySQL incorrectly aborted on warnings within stored routines and triggers. (Bug #20028) * *Note `mysqldump --xml': mysqldump. produced invalid XML for *Note `BLOB': blob. data. (Bug #19745) * The range analysis optimizer did not take into account predicates for which an index could be used after reading `const' tables. In some cases this resulted in nonoptimal execution plans. (Bug #19579) * `FLUSH INSTANCES' in Instance Manager triggered an assertion failure. (Bug #19368) * For a debug server, a reference to an undefined user variable in a prepared statement executed with *Note `EXECUTE': execute. caused an assertion failure. (Bug #19356) * Within a trigger for a base table, selecting from a view on that base table failed. (Bug #19111) * The value of the `warning_count' system variable was not being calculated correctly (also affecting `SHOW COUNT(*) WARNINGS'). (Bug #19024) * `DELETE IGNORE' could hang for foreign key parent deletes. (Bug #18819) * `InnoDB' used table locks (not row locks) within stored functions. (Bug #18077) * *Note `mysql': mysql. would lose its connection to the server if its standard output was not writable. (Bug #17583) * At shutdown, Instance Manager told guarded server instances to stop, but did not wait until they actually stopped. (Bug #17486) * `mysql-test-run' did not work correctly for RPM-based installations. (Bug #17194) * A client library crash was caused by executing a statement such as `SELECT * FROM t1 PROCEDURE ANALYSE()' using a server side cursor on a table `t1' that does not have the same number of columns as the output from `PROCEDURE ANALYSE()'. (Bug #17039) * The `WITH CHECK OPTION' for a view failed to prevent storing invalid column values for *Note `UPDATE': update. statements. (Bug #16813) * *Note `ALTER TABLE': alter-table. was not able to rename a view. (Bug #14959) * Statements such as *Note `DROP PROCEDURE': drop-procedure. and *Note `DROP VIEW': drop-view. were written to the binary log too late due to a race condition. (Bug #14262) * A literal string in a `GROUP BY' clause could be interpreted as a column name. (Bug #14019) * Entries in the slow query log could have an incorrect `Rows_examined' value. (Bug #12240) * Lack of validation for input and output *Note `TIME': time. values resulted in several problems: `SEC_TO_TIME()' in some cases did not clip large values to the *Note `TIME': time. range appropriately; `SEC_TO_TIME()' treated `BIGINT UNSIGNED' values as signed; only truncation warnings were produced when both truncation and out-of-range *Note `TIME': time. values occurred. (Bug #11655, Bug #20927) * Several string functions could return incorrect results when given very large length arguments. (Bug #10963) * `FROM_UNIXTIME()' did not accept arguments up to `POWER(2,31)-1', which it had previously. (Bug #9191) * *Note `OPTIMIZE TABLE': optimize-table. with `myisam_repair_threads' > 1 could result in `MyISAM' table corruption. (Bug #8283)  File: manual.info, Node: news-5-1-12, Next: news-5-1-11, Prev: news-5-1-13, Up: news-5-1-x D.1.56 Changes in MySQL 5.1.12 (24 October 2006) ------------------------------------------------ This is a new Beta development release, fixing recently discovered bugs. This section documents all changes and bug fixes that have been applied since the last official MySQL release. If you would like to receive more fine-grained and personalized _update alerts_ about fixes that are relevant to the version and features you use, please consider subscribing to _MySQL Enterprise_ (a commercial MySQL offering). For more details, please see http://www.mysql.com/products/enterprise. *Functionality added or changed:* * *Incompatible Change*: *MySQL Cluster*: MySQL Cluster node and system restarts formerly required that all fragments use the same local checkpoint (LCP); beginning with this version, it is now possible for different fragments to use different LCPs during restarts. This means that data node file systems must be rebuilt as part of any upgrade to this version by restarting all data nodes with the `--initial' option. See *Note mysql-cluster-upgrade-downgrade-compatibility-5.1::, and related sections of the Manual before upgrading a MySQL Cluster to version 5.1.12 or later. (Bug #21478, Bug #21271) * *Incompatible Change*: In the *Note `INFORMATION_SCHEMA.EVENTS': events-table. table, the `EVENT_DEFINITION' column now contains the SQL executed by a scheduled event. The `EVENT_BODY' column now contains the language used for the statement or statements shown in `EVENT_DEFINITION'. In MySQL 5.1, the value shown in `EVENT_BODY' is always `SQL'. These changes were made to bring this table into line with the *Note `INFORMATION_SCHEMA.ROUTINES': routines-table. table, and that table's `ROUTINE_BODY' and `ROUTINE_DEFINITION' columns. (Bug #16992) * *Incompatible Change*: For `GRANT' and `REVOKE', `ON *' previously granted and revoked privileges for the default database if there was a default database and global privileges if there was none. Now `ON *' requires a default database and produces an error if there is none. * *Incompatible Change*: Support for the BerkeleyDB (`BDB') engine has been dropped from this release. Any existing tables that are in BDB format will not be readable from within MySQL from 5.1.12 or newer. You should convert your tables to another storage engine _before_ upgrading to 5.1.12. Because of this change, the `SHOW [BDB] LOGS' statement has been dropped. * *Incompatible Change*: A number of MySQL constructs are now prohibited in partitioning expressions, beginning with this release. These include the following: * A number of MySQL functions. For a complete list of these, see *Note partitioning-limitations-functions::. * The bit operators `|', `&', `^', `<<', `>>', and `~'. * Nested function calls. * Calls to stored routines, UDFs, or plugins. * Character-to-integer conversions involving non-8-bit character sets or any of the `latin1_german2_ci', `latin2_czech_cs', or `cp1250_czech_cs' collations. These restrictions were added in part as a result of Bug#18198 and related bug reports. For more information about these and other restrictions on partitioned tables in MySQL, see *Note partitioning-limitations::. * *Incompatible Change*: The permitted values for and behavior of the `event_scheduler' system variable have changed. Permitted values are now `ON', `OFF', and `DISABLED', with `OFF' being the default. It is not possible to change its value to or from `DISABLED' while the server is running. For details, see *Note events-overview::. * *Incompatible Change*: The plugin interface has changed: The `st_mysql_plugin' structure has a new `license' member to indicate the license type. (The permissible values are defined in `mysql/plugin.h'.) This change is not backward compatible, so the API version (`MYSQL_PLUGIN_INTERFACE_VERSION') has changed. For additional information, see *Note writing-plugins::. * *Incompatible Change*: The full-text parser plugin interface has changed in two ways: * The `MYSQL_FTPARSER_PARAM' structure has a new `flags' member. This is zero if there are no special flags, or `MYSQL_FTFLAGS_NEED_COPY', which means that `mysql_add_word()' must save a copy of the word (that is, it cannot use a pointer to the word because the word is in a buffer that will be overwritten.) This flag might be set or reset by MySQL before calling the parser plugin, by the parser plugin itself, or by the `mysql_parse()' function. * The `mysql_parse()' and `mysql_add_word()' functions now take a `MYSQL_FTPARSER_PARAM' as their first argument, not a `MYSQL_FTPARSER_PARAM::mysql_ftparam' as before. These changes are not backward compatible, so the API version (`MYSQL_FTPARSER_INTERFACE_VERSION') has changed. For additional information, see *Note writing-plugins::. * *Incompatible Change*: Storage engines can be pluggable at runtime, so the distinction between disabled and invalid storage engines no longer applies. This affects the `NO_ENGINE_SUBSTITUTION' SQL mode, as described in *Note server-sql-mode::. * *Incompatible Change*: The namespace for scheduled events has changed, such that events are no longer unique to individual users. This also means that a user with the `EVENT' privilege on a given database can now view, alter, or drop any events defined on that database. If you used scheduled events in an earlier MySQL 5.1 release, you should rename any of them having the same name and defined on the same database but belonging to different users--so that all events in a given database have unique names--_before_ upgrading to 5.1.12 (or newer). For additional information, see *Note events-privileges::. * *Important Change*: *Partitioning*: *MySQL Cluster*: It is no longer possible to create Cluster tables using any partitioning type other than [`LINEAR'] `KEY'. Attempting to do so now raises an error. * *Important Change*: *MySQL Cluster*: *Note `LOAD DATA INFILE': load-data. no longer causes an implicit commit for all storage engines. It now causes an implicit commit only for tables using the *Note `NDB': mysql-cluster. storage engine. (Bug #11151) * *Important Change*: *MySQL Cluster*: The status variables `Ndb_connected_host' and `Ndb_connected_port' were renamed to `Ndb_config_from_host' and `Ndb_config_from_port', respectively. * *Important Change*: *Replication*: The default value for the `--binlog-format' server option is now `MIXED'. * *MySQL Cluster*: The *Note `ndb_config': mysql-cluster-programs-ndb-config. utility now accepts `-c' as a short form of the `--ndb-connectstring' option. (Bug #22295) * *MySQL Cluster*: Added the `--bind-address' option for *Note `ndbd': mysql-cluster-programs-ndbd. This permits a data node process to be bound to a specific network interface. (Bug #22195) * *MySQL Cluster*: The `Ndb_number_of_storage_nodes' system variable was renamed to `Ndb_number_of_data_nodes'. (Bug #20848) * *MySQL Cluster*: The *Note `HELP': help. command in the Cluster management client now provides command-specific help. For example, `HELP RESTART' in *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. provides detailed information about the `RESTART' command. (Bug #19620) * *MySQL Cluster*: A number of erroneous, misleading, or missing error messages have been corrected. (Bug #17297, Bug #19543) * *MySQL Cluster*: Backup messages are no longer printed to the cluster log. * *MySQL Cluster*: Added the `--ndb-use-copying-alter-table' option to *Note `mysqld': mysqld. to provide a fallback in case of problems with online *Note `ALTER TABLE': alter-table. operations on *Note `NDB': mysql-cluster. tables. * *Replication*: The default binary log format (as used during replication) is now Mixed based, automatically using a combination of row-based and statement based log events as appropriate. * *Cluster API*: Two new NDB API methods `aggregate()' and `validate()' were added to the `Table' class. This was done to rectify the following issues: * Under some conditions, the data distribution could become unbalanced in a MySQL Cluster with 2 or more node groups following the creation of a new table. * Data was stored unevenly between partitions due to all *Note `BLOB': blob. data being placed in partition 0. (Bug #21690) * The number of `InnoDB' threads is no longer limited to 1,000 on Windows. (Bug #22268) * The `STATE' column of the *Note `INFORMATION_SCHEMA.PROCESSLIST': processlist-table. table was increased from 30 to 64 characters to accommodate longer state values. (Bug #21652) * *Note `mysqldump': mysqldump. now has a `--flush-privileges' option. It causes *Note `mysqldump': mysqldump. to emit a *Note `FLUSH PRIVILEGES': flush. statement after dumping the `mysql' database. This option should be used any time the dump contains the `mysql' database and any other database that depends on the data in the `mysql' database for proper restoration. (Bug #21424) * *Note `mysqlslap': mysqlslap. threads now try to connect up to 10 times if the initial connect attempt fails. (Bug #21297) * For *Note `mysqldump': mysqldump, the output generated by the server when using the `--xml' option has changed with regard to null values. It now matches the output from *Note `mysqldump': mysqldump. `--xml'. That is, a column containing a `NULL' value is now reported as whereas a column containing the string value `'NULL'' is reported as NULL and a column containing an empty string is reported as (Bug #21263) * The *Note `mysqld': mysqld. and `mysqlmanager' man pages have been reclassified from volume 1 to volume 8. (Bug #21220) * `InnoDB' now honors `IGNORE INDEX'. Previously using `IGNORE INDEX' in cases where an index sort would be slower than a filesort had no effect when used with `InnoDB' tables. (Bug #21174) * *Note `TIMESTAMP': datetime. columns that are `NOT NULL' now are reported that way by *Note `SHOW COLUMNS': show-columns. and `INFORMATION_SCHEMA'. (Bug #20910) * Memory consumption of the `InnoDB' data dictionary cache was roughly halved by cleaning up the data structures. (Bug #20877) * The `BINARY' keyword now is forbidden as a data type attribute in stored routines (for example, `DECLARE v1 VARCHAR(25) BINARY'), because *Note `DECLARE': declare. does not support collations, and in this context `BINARY' specifies the binary collation of the variable's character set. (Bug #20701) * The following statements now can be executed as prepared statements (using *Note `PREPARE': prepare. plus *Note `EXECUTE': execute.): CACHE INDEX CHANGE MASTER CHECKSUM {TABLE | TABLES} {CREATE | RENAME | DROP} DATABASE {CREATE | RENAME | DROP} USER FLUSH {TABLE | TABLES | TABLES WITH READ LOCK | HOSTS | PRIVILEGES | LOGS | STATUS | MASTER | SLAVE | DES_KEY_FILE | USER_RESOURCES} GRANT REVOKE KILL LOAD INDEX INTO CACHE RESET {MASTER | SLAVE | QUERY CACHE} SHOW BINLOG EVENTS SHOW CREATE {PROCEDURE | FUNCTION | EVENT | TABLE | VIEW} SHOW {AUTHORS | CONTRIBUTORS | WARNINGS | ERRORS} SHOW {MASTER | BINARY} LOGS SHOW {MASTER | SLAVE} STATUS SLAVE {START | STOP} INSTALL PLUGIN UNINSTALL PLUGIN (Bug #20665) * In the *Note `INFORMATION_SCHEMA.ROUTINES': routines-table. table the `ROUTINE_DEFINITION' column now is defined as `NULL' rather than `NOT NULL'. Also, `NULL' rather than the empty string is returned as the column value if the user does not have sufficient privileges to see the routine definition. (Bug #20230) * The *Note `mysqldumpslow': mysqldumpslow. script has been moved from client RPM packages to server RPM packages. This corrects a problem where *Note `mysqldumpslow': mysqldumpslow. could not be used with a client-only RPM install, because it depends on *Note `my_print_defaults': my-print-defaults. which is in the server RPM. (Bug #20216) * The MySQL distribution now compiles on UnixWare 7.13. (Bug #20190) * `configure' now defines the symbol `DBUG_ON' in `config.h' to indicate whether the source tree is configured to be compiled with debugging support. (Bug #19517) * *Note `TEXT': blob. and *Note `BLOB': blob. columns do not support `DEFAULT' values. However, when a default of `''' was specified, the specification was silently ignored. This now results in a warning, or an error in strict mode. (Bug #19498) * For *Note `mysqlshow': mysqlshow, if a database name argument contains wildcard characters (such as ``_'') but matches a single database name exactly, treat the name as a literal name. This enables a command such as *Note `mysqlshow information_schema': mysqlshow. to work without having to escape the wildcard character. (Bug #19147) * The source distribution has been updated so that the UDF example can be compiled under Windows with `CMake'. See *Note udf-compiling::. (Bug #19121) * The default value of the `tmp_table_size' system variable was lowered from 32MB to 16MB because it is bounded by the value of `max_heap_table_size', which has a default of 16MB. (Bug #18875) * Log table changes: By default, the log tables use the `CSV' storage engine, as before. But now the log tables can be altered to use the `MyISAM' storage engine. You cannot use *Note `ALTER TABLE': alter-table. to alter a log table that is in use. The log must be disabled first. No engines other than `CSV' or `MyISAM' are legal for the log tables. The use of *Note `DROP TABLE': drop-table. for log tables is similarly restricted: It cannot be used to drop a log table that is in use. The log must be disabled first. (These changes also correct a deadlock that occurred for an attempt to drop an in-use log table.) (Bug #18559) * Added the `--set-charset' option to *Note `mysqlbinlog': mysqlbinlog. to enable the character set to be specified for processing binary log files. (Bug #18351) * The `ExtractValue()' function now produces an error when passed an XML fragment that is not well-formed. (Previously, the function permitted invalid XML fragments to be used.) (Bug #18201) * On Windows, typing `Control+C' while a query was running caused the *Note `mysql': mysql. client to crash. Now it causes *Note `mysql': mysql. to attempt to kill the current statement. If this cannot be done, or `Control+C' is typed again before the statement is killed, *Note `mysql': mysql. exits. (In other words, *Note `mysql': mysql.'s behavior with regard to `Control+C' is now the same as it is on Unix platforms.) (Bug #17926) See also Bug #1989. * The bundled yaSSL library licensing has added a FLOSS exception similar to MySQL to resolve licensing incompatibilities with MySQL. (See the `extra/yassl/FLOSS-EXCEPTIONS' file in a MySQL source distribution for details.) (Bug #16755) * *Note `SHOW CREATE TABLE': show-create-table. now shows constraints for `InnoDB' tables. (Bug #16614) * *Note `EXPLAIN EXTENDED': explain. now shows a `filtered' column that is an estimated percentage of the examined rows that will be joined with the previous tables. This was added while dealing with a problem of MySQL choosing the wrong index for some queries. (Bug #14940) * The *Note `mysql': mysql. client now permits `\l' in the `prompt' command argument, to insert the current delimiter into the prompt. (Bug #14448) * The *Note `mysql': mysql. client used the default character set if it automatically reconnected to the server, which is incorrect if the character set had been changed. To enable the character set to remain synchronized on the client and server, the *Note `mysql': mysql. command `charset' (or `\C') that changes the default character set and now also issues a `SET NAMES' statement. The changed character set is used for reconnects. (Bug #11972) * The `LEFT()' and `RIGHT()' functions return `NULL' if any argument is `NULL'. (Bug #11728) * If a *Note `DROP VIEW': drop-view. statement named multiple views, it stopped with an error if a nonexistent view was named and did not drop the remaining views. Now it continues on and reports an error at the end, similar to *Note `DROP TABLE': drop-table. (Bug #11551) * For a successful dump, *Note `mysqldump': mysqldump. now writes a SQL comment to the end of the dump file in the following format: -- Dump completed on YYYY-MM-DD hh:mm:ss (Bug #10877) * There were several issues regarding how *Note `SHOW STATUS': show-status. affected some status variables and logging which could impact monitoring the MySQL Server. The behavior of this statement has been modified in two ways: * *Note `SHOW STATUS': show-status. is no longer logged to the slow query log. * *Note `SHOW STATUS': show-status. no longer updates any session status variables, except for `com_show_status'. However, *Note `SHOW STATUS': show-status. continues to update _global_ status variables to enable monitoring of what the server is actually doing. This is because *Note `SHOW STATUS': show-status. creates temporary tables that may affect performance if it is called excessively often. (Bug #10210) See also Bug #19764. * For spatial data types, the server formerly returned these as `VARSTRING' values with a binary collation. Now the server returns spatial values as *Note `BLOB': blob. values. (Bug #10166) * The `LOAD DATA FROM MASTER' and `LOAD TABLE FROM MASTER' statements are deprecated. See *Note load-data-from-master::, for recommended alternatives. (Bug #9125, Bug #20596, Bug #14399, Bug #12187, Bug #15025, Bug #18822) * For the *Note `mysql': mysql. client, typing `Control+C' causes *Note `mysql': mysql. to attempt to kill the current statement. If this cannot be done, or `Control+C' is typed again before the statement is killed, *Note `mysql': mysql. exits. Previously, `Control+C' caused *Note `mysql': mysql. to exit in all cases. (Bug #1989) * It is no longer possible to create partitioned tables using the `CSV' storage engine. * Binary MySQL distributions no longer include a `mysqld-max' server. Instead, distributions contain a binary that includes the features previously included in the `mysqld-max' binary. * *Note `SHOW STATUS': show-status. is no longer logged to the slow query log. * Program Database files (extension `.pdb') are now included by default in Windows distributions. These can be used to help diagnose problems with *Note `mysqld': mysqld. and other tools. See *Note debugging-server::. * `INFORMATION_SCHEMA' contains new tables, *Note `GLOBAL_STATUS': status-table, *Note `SESSION_STATUS': status-table, *Note `GLOBAL_VARIABLES': variables-table, and *Note `SESSION_VARIABLES': variables-table, that correspond to the output from the `SHOW {GLOBAL|SESSION} STATUS' and `SHOW {GLOBAL|SESSION} VARIABLES' statements. * *Note `SHOW STATUS': show-status. no longer updates any session status variables, except for `com_show_status'. * A new system variable, `lc_time_names', specifies the locale that controls the language used to display day and month names and abbreviations. This variable affects the output from the `DATE_FORMAT()', `DAYNAME()' and `MONTHNAME()' functions. See *Note locale-support::. * Using `--with-debug' to configure MySQL with debugging support enables you to use the `--debug="d,parser_debug"' option when you start the server. This causes the Bison parser that is used to process SQL statements to dump a parser trace to the server's standard error output. Typically, this output is written to the error log. * The bundled yaSSL library was upgraded to version 1.3.7. * The Instance Manager `--passwd' option has been renamed to `--print-password-line'. Other options were added to enable management of the IM password file from the command line: `--add-user', `--drop-user', `--edit-user', `--list-users', `--check-password-file', `--clean-password-file', `--username', and `--password'. The `--mysqld-safe-compatible' option was added to cause the Instance Manner to act similarly to *Note `mysqld_safe': mysqld-safe. * Added the *Note `SHOW CONTRIBUTORS': show-contributors. statement. * The general query log and slow query logs now can be enabled or disabled at runtime with the `general_log' and `slow_query_log' system variables, and the name of the log files can be changed by setting the `general_log_file' and `slow_query_log_file' system variables. See *Note query-log::, and *Note slow-query-log::. *Bugs fixed:* * *Security Fix*: A stored routine created by one user and then made accessible to a different user using *Note `GRANT EXECUTE': grant. could be executed by that user with the privileges of the routine's definer. (Bug #18630, CVE-2006-4227) * *Security Fix*: On Linux, and possibly other platforms using case-sensitive file systems, it was possible for a user granted rights on a database to create or access a database whose name differed only from that of the first by the case of one or more letters. (Bug #17647, CVE-2006-4226) * *Security Fix*: If a user has access to `MyISAM' table T, that user can create a `MERGE' table M that accesses T. However, if the user's privileges on T are subsequently revoked, the user can continue to access T by doing so through M. If this behavior is undesirable, you can start the server with the new `--skip-merge' option to disable the `MERGE' storage engine. (Bug #15195, CVE-2006-4031) * *Incompatible Change*: For `utf8' columns, the full-text parser incorrectly considered several nonword punctuation and whitespace characters as word characters, causing some searches to return incorrect results. The fix involves a change to the full-text parser, so any tables that have `FULLTEXT' indexes on `utf8' columns must be repaired with *Note `REPAIR TABLE': repair-table.: REPAIR TABLE TBL_NAME QUICK; (Bug #19580) * *MySQL Cluster*: *Packaging*: The *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. program was included in both the `MySQL-ndb-tools' and `MySQL-ndb-management' RPM packages, resulting in a conflict if both were installed. Now *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. is included only in `MySQL-ndb-tools'. (Bug #21058) * *MySQL Cluster*: *Replication*: A `DELETE FROM table' with no `WHERE' clause (deleting all rows) running concurrently with *Note `INSERT': insert. statements on a storage engine with row-level locking (such as *Note `NDB': mysql-cluster.) could produce inconsistent results when using statement-based replication. (Bug #19066) * *MySQL Cluster*: *Replication*: (Replication): A node failure could send duplicate events, causing a *Note `mysqld': mysqld. replicating tables containing *Note `BLOB': blob.s to crash. * *MySQL Cluster*: (NDB API): Inacivity timeouts for scans were not correctly handled. (Bug #23107) * *MySQL Cluster*: Inserting into an *Note `NDB': mysql-cluster. table failed when the table had no primary key but had a unique key added after table was created on one or more `NOT NULL' columns. This occurred when the unique key had been adding using either *Note `ALTER TABLE': alter-table. or `CREATE UNIQUE KEY'. (Bug #22838) * *MySQL Cluster*: (NDB API): Attempting to read a nonexistent tuple using `Commit' mode for `NdbTransaction::execute()' caused node failures. (Bug #22672) * *MySQL Cluster*: The `--help' output from *Note `NDB': mysql-cluster. binaries did not include file-related options. (Bug #21994) * *MySQL Cluster*: Setting `TransactionDeadlockDetectionTimeout' to a value greater than 12000 would cause scans to deadlock, time out, fail to release scan records, until the cluster ran out of scan records and stopped processing. (Bug #21800) * *MySQL Cluster*: A scan timeout returned Error 4028 (`Node failure caused abort of transaction') instead of Error 4008 (`Node failure caused abort of transaction...'). (Bug #21799) * *MySQL Cluster*: The node recovery algorithm was missing a version check for tables in the `ALTER_TABLE_COMMITTED' state (as opposed to the `TABLE_ADD_COMMITTED' state, which has the version check). This could cause inconsistent schemas across nodes following node recovery. (Bug #21756) * *MySQL Cluster*: A memory leak occurred when running *Note `ndb_mgm -e "SHOW"': mysql-cluster-programs-ndb-mgm. (Bug #21670) * *MySQL Cluster*: The server provided a nondescriptive error message when encountering a fatally corrupted REDO log. (Bug #21615) * *MySQL Cluster*: The output for the `--help' option used with *Note `NDB': mysql-cluster. executable programs (such as *Note `ndbd': mysql-cluster-programs-ndbd, *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm, *Note `ndb_restore': mysql-cluster-programs-ndb-restore, *Note `ndb_config': mysql-cluster-programs-ndb-config, and others mentioned in *Note mysql-cluster-programs::) referred to the `Ndb.cfg' file, instead of to `my.cnf'. (Bug #21585) * *MySQL Cluster*: A partial rollback could lead to node restart failures. (Bug #21536) * *MySQL Cluster*: Partition distribution keys were updated only for the primary and starting replicas during node recovery. This could lead to node failure recovery for clusters having an odd number of replicas. *Note*: For best results, use values for `NumberOfReplicas' that are even powers of 2. (Bug #21535) * *MySQL Cluster*: The *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. management client did not set the exit status on errors, always returning 0 instead. (Bug #21530) * *MySQL Cluster*: The failure of a unique index read due to an invalid schema version could be handled incorrectly in some cases, leading to unpredictable results. (Bug #21384) * *MySQL Cluster*: Attempting to create an *Note `NDB': mysql-cluster. table on a MySQL server with an existing non-Cluster table with the same name in the same database could result in data loss or corruption. Now, if such a table is encountered during autodiscovery, a warning is written to the error log of the affected *Note `mysqld': mysqld, and the local table is overwritten. (Bug #21378) * *MySQL Cluster*: Cluster logs were not rotated following the first rotation cycle. (Bug #21345) * *MySQL Cluster*: In a cluster with more than 2 replicas, a manual restart of one of the data nodes could fail and cause the other nodes in the same node group to shut down. (Bug #21213) * *MySQL Cluster*: The *Note `ndb_size.pl': mysql-cluster-programs-ndb-size-pl. script did not account for *Note `TEXT': blob. and *Note `BLOB': blob. column values correctly. (Bug #21204) * *MySQL Cluster*: Some queries involving joins on very large *Note `NDB': mysql-cluster. tables could crash the MySQL server. (Bug #21059) * *MySQL Cluster*: Condition pushdown did not work correctly with *Note `DATETIME': datetime. columns. (Bug #21056) * *MySQL Cluster*: Responses to the `ALL DUMP 1000' management client command were printed multiple times in the cluster log for each cluster node. (Bug #21044) * *MySQL Cluster*: The message `Error 0 in readAutoIncrementValue(): no Error' was written to the error log whenever *Note `SHOW TABLE STATUS': show-table-status. was performed on a Cluster table that did not have an `AUTO_INCREMENT' column. (Bug #21033) * *MySQL Cluster*: Restarting a data node while DDL operations were in progress on the cluster could cause other data nodes to fail. This could also lead to *Note `mysqld': mysqld. hanging or crashing under some circumstances. (Bug #21017, Bug #21050) * *MySQL Cluster*: In some situations with a high disk-load, writing of the redo log could hang, causing a crash with the error message `GCP STOP detected'. (Bug #20904) * *MySQL Cluster*: A race condition could in some cirumstances following a *Note `DROP TABLE': drop-table. (Bug #20897) * *MySQL Cluster*: Under some circumstances, local checkpointing would hang, keeping any unstarted nodes from being started. (Bug #20895) * *MySQL Cluster*: When the redo buffer ran out of space, a `Pointer too large' error was raised and the cluster could become unusable until restarted with `--initial'. (Bug #20892) * *MySQL Cluster*: A vague error message was returned when reading both schema files during a restart of the cluster. (Bug #20860) * *MySQL Cluster*: The repeated creating and dropping of a table would eventually lead to *Note `NDB': mysql-cluster. Error 826, `Too many tables and attributes ... Insufficient space'. (Bug #20847) * *MySQL Cluster*: When attempting to restart the cluster following a data import, the cluster failed during Phase 4 of the restart with `Error 2334: Job buffer congestion'. (Bug #20774) * *MySQL Cluster*: *Note `REPLACE': replace. statements did not work correctly on an *Note `NDB': mysql-cluster. table having both a primary key and a unique key. In such cases, proper values were not set for columns which were not explicitly referenced in the statement. (Bug #20728) * *MySQL Cluster*: The server did not honor the value set for `ndb_cache_check_time' in the `my.cnf' file. (Bug #20708) * *MySQL Cluster*: Truncating a table on one *Note `mysqld': mysqld. caused other *Note `mysqld': mysqld. processes connected to the cluster to return `ERROR 1412 (HY000): Table definition has changed, please retry transaction' on subsequent queries. (Bug #20705) * *MySQL Cluster*: Using an invalid node ID with the management client `STOP' command could cause *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. to hang. (Bug #20575) * *MySQL Cluster*: Renaming of table columns was not supported as fast a *Note `ALTER TABLE': alter-table. for NDB tables. (Bug #20456) * *MySQL Cluster*: *Note `ndb_size.pl': mysql-cluster-programs-ndb-size-pl. and *Note `ndb_error_reporter': mysql-cluster-programs-ndb-error-reporter. were missing from RPM packages. (Bug #20426) * *MySQL Cluster*: Running *Note `ndbd': mysql-cluster-programs-ndbd. `--nowait-nodes=ID ' where ID was the node ID of a node that was already running would fail with an invalid error message. (Bug #20419) * *MySQL Cluster*: Data nodes added while the cluster was running in single user mode were all assigned node ID 0, which could later cause multiple node failures. Adding nodes while in single user mode is no longer possible. (Bug #20395) * *MySQL Cluster*: The *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client command `ALL CLUSTERLOG STATISTICS=15' had no effect. (Bug #20336) * *MySQL Cluster*: A node failure during a scan could sometime cause the node to crash when restarting too quickly following the failure. (Bug #20197) * *MySQL Cluster*: The failure of a data node when preparing to commit a transaction (that is, while the node's status was `CS_PREPARE_TO_COMMIT') could cause the failure of other cluster data nodes. (Bug #20185) * *MySQL Cluster*: *Note `SHOW ENGINE NDB STATUS': show-engine. could sometimes return an incorrect value of `0' for the latest epoch, which could cause problems with synchronizing the binlog. (Bug #20142) * *MySQL Cluster*: An internal formatting error caused some management client error messages to be unreadable. (Bug #20016) * *MySQL Cluster*: Creating tables with variable-size columns caused `DataMemory' to be used but not freed when the tables were dropped. (Bug #20007) * *MySQL Cluster*: Renaming a table in such a way as to move it to a different database failed to move the table's indexes. (Bug #19967) * *MySQL Cluster*: Running management client commands while `mgmd' was in the process of disconnecting could cause the management server to fail. (Bug #19932) * *MySQL Cluster*: Under certain conditions, a starting node could miss transactions, leading to inconsistencies between the primary and backup replicas. (Bug #19929) * *MySQL Cluster*: An uncommitted row could sometimes be checkpointed and thus incorrectly included in a backup. (Bug #19928) * *MySQL Cluster*: In some cases where `SELECT COUNT(*)' from an *Note `NDB': mysql-cluster. table should have yielded an error, `MAX_INT' was returned instead. (Bug #19914) * *MySQL Cluster*: *Note `TEXT': blob. columns in Cluster tables having both an explicit primary key and a unique key were not correctly updated by *Note `REPLACE': replace. statements. (Bug #19906) * *MySQL Cluster*: The cluster's data nodes failed while trying to load data when `NoOfFrangmentLogFiles' was set equal to 1. (Bug #19894) * *MySQL Cluster*: Following the restart of a management node, the Cluster management client did not automatically reconnect. (Bug #19873) * *MySQL Cluster*: Restoring a backup with *Note `ndb_restore': mysql-cluster-programs-ndb-restore. failed when the backup had been taken from a cluster whose `DataMemory' had been completely used up. (Bug #19852) * *MySQL Cluster*: Error messages given when trying to make online changes to parameters such as `NoOfReplicas' that can only be changed using a complete shutdown and restart of the cluster did not indicate the true nature of the problem. (Bug #19787) * *MySQL Cluster*: Under some circumstances, repeated DDL operations on one `mysqld' could cause failure of a second `mysqld' attached to the same cluster. (Bug #19770) * *MySQL Cluster*: *Note `ndb_restore': mysql-cluster-programs-ndb-restore. did not always make clear that it had recovered successfully from temporary errors while restoring a cluster backup. (Bug #19651) * *MySQL Cluster*: Resources for unique indexes on Cluster table columns were incorrectly allocated, so that only one-fourth as many unique indexes as indicated by the value of `UniqueHashIndexes' could be created. (Bug #19623) * *MySQL Cluster*: *Note `LOAD DATA LOCAL': load-data. failed to ignore duplicate keys in Cluster tables. (Bug #19496) * *MySQL Cluster*: For *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd, Valgrind revealed problems with a memory leak and a dependency on an uninitialized variable. (Bug #19318, Bug #20333) * *MySQL Cluster*: A *Note `DELETE': delete. of many rows immediately followed by an *Note `INSERT': insert. on the same table could cause the *Note `ndbd': mysql-cluster-programs-ndbd. process on the backup replica to crash. (Bug #19293) * *MySQL Cluster*: An excessive number of *Note `ALTER TABLE': alter-table. operations could cause the cluster to fail with *Note `NDB': mysql-cluster. error code 773 (`Out of string memory, please modify StringMemory'). (Bug #19275) * *MySQL Cluster*: A problem with error handling when `ndb_use_exact_count' was enabled could lead to incorrect values returned from queries using `COUNT()'. A warning is now returned in such cases. (Bug #19202) * *MySQL Cluster*: In rare situations with resource shortages, a crash could result from an insufficient number of `IndexScanOperation' objects. (Bug #19198) * *MySQL Cluster*: Running out of `DataMemory' could sometimes crash *Note `ndbd': mysql-cluster-programs-ndbd. and *Note `mysqld': mysqld. processes. (Bug #19185) * *MySQL Cluster*: It was possible to use port numbers greater than 65535 for `ServerPort' in the `config.ini' file. (Bug #19164) * *MySQL Cluster*: *Note `ndb_mgm -e show | head': mysql-cluster-programs-ndb-mgm. would hang after displaying the first 10 lines of output. (Bug #19047) * *MySQL Cluster*: The error returned by the cluster when too many nodes were defined did not make clear the nature of the problem. (Bug #19045) * *MySQL Cluster*: The management client `ALL STOP' command shut down `mgmd' processes (as well as *Note `ndbd': mysql-cluster-programs-ndbd. processes). (Bug #18966) * *MySQL Cluster*: *Note `TRUNCATE TABLE': truncate-table. failed to reset the `AUTO_INCREMENT' counter. (Bug #18864) * *MySQL Cluster*: Restarting a failed node could sometimes crash the cluster. (Bug #18782) * *MySQL Cluster*: Trying to create or drop a table while a node was restarting caused the node to crash. This is now handled by raising an error. (Bug #18781) * *MySQL Cluster*: Repeated `CREATE' - *Note `INSERT': insert. - `DROP' operations on tables could in some circumstances cause the MySQL table definition cache to become corrupt, so that some *Note `mysqld': mysqld. processes could access table information but others could not. (Bug #18595) * *MySQL Cluster*: A *Note `CREATE TABLE': create-table. statement involving foreign key constraints raised an error rather than being silently ignored (see *Note create-table::). This bug affected Cluster in MySQL 5.1 only. (Bug #18483) * *MySQL Cluster*: The server failed with a nondescriptive error message when out of data memory. (Bug #18475) * *MySQL Cluster*: For *Note `NDB': mysql-cluster. and possibly `InnoDB' tables, a `BEFORE UPDATE' trigger could insert incorrect values. (Bug #18437) * *MySQL Cluster*: The `DATA_LENGTH' and `AVG_ROW_LENGTH' columns of the *Note `INFORMATION_SCHEMA.TABLES': tables-table. table did not report the size of variable-width column values correctly. See *Note tables-table::, for more information. (Bug #18413) * *MySQL Cluster*: *Note `SELECT ... FOR UPDATE': select. failed to lock the selected rows. (Bug #18184) * *MySQL Cluster*: (Disk Data): Deletes from Disk Data tables used a nonoptimal scan to find the rows to be deleted, resulting in poor performance. The fix causes disk order rather than memory order to be used, and can improve performance of Disk Data deletes by up to ~300% in some cases. (Bug #17929) * *MySQL Cluster*: *Note `perror': perror. did not properly report *Note `NDB': mysql-cluster. error codes. (Bug #16561) * *MySQL Cluster*: A problem with takeover during a system restart caused ordered indexes to be rebuilt incorrectly. This also adversely affected MySQL Cluster Replication. (Bug #15303) * *MySQL Cluster*: A cluster data node could crash when an ordered index became full before the table containing the index was full. (Bug #14935) * *MySQL Cluster*: The management client `ALL STATUS' command could sometimes report the status of some data nodes incorrectly. (Bug #13985) * *MySQL Cluster*: New *Note `mysqld': mysqld. processes were permitted to connect without a restart of the cluster, causing the cluster to crash. (Bug #13266) * *MySQL Cluster*: Cluster system status variables were not updated properly. (Bug #11459) * *MySQL Cluster*: (NDBAPI): Update operations on blobs were not checked for illegal operations. *Note*: Read locks with blob update operations are now upgraded from read committed to read shared. * *MySQL Cluster*: The loss of one or more data nodes could sometimes cause *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. to use a high amount of CPU (15 percent or more, as opposed to 1 to 2 percent normally). * *Partitioning*: Old partition and subpartition files were not always removed following `ALTER TABLE ... REORGANIZE PARTITION' statements. (Bug #20770) * *Cluster Replication*: *Replication*: In some cases, a large number of MySQL servers sending requests to the cluster simultaneously could cause the cluster to crash. This could also be triggered by many *Note `NDB': mysql-cluster. API clients making simultaneous event subscriptions or unsubscriptions. (Bug #20683) * *Cluster Replication*: *Replication*: Data definition and data manipulation statements on different tables were not serialized correctly in the binary log. For example, there was no guarantee that a *Note `CREATE TABLE': create-table. statement and an update on a different table would occur in the same order in the binary log as they did on the cluster being replicated. (Bug #18947) * *Replication*: *Note `BIT': numeric-types. columns were not replicated properly under row-based replication. (Bug #22550) * *Replication*: For row-based replication, log rotation could occur at an improper time. (Bug #21474) * *Replication*: In mixed-format binary logging mode, stored functions, triggers, and views that use functions in their body that require row-based logging did not replicate reliably because the logging did not switch from statement-based to row-based format. For example, `INSERT INTO t SELECT FROM v', where `v' is a view that selects `UUID()' could cause problems. This limitation has been removed. (Bug #20930) * *Replication*: A race condition during slave server shutdown caused an assert failure. (Bug #20850) * *Replication*: With mixed-format binary logging, *Note `INSERT DELAYED': insert-delayed. statements were logged using statement-based logging, and they did not replicate properly for statements that used values such as `UUID()', `RAND()', or user-defined variables that require row-based logging. To correct this, the `DELAYED' handler thread how switches to row-based logging if the logging format is mixed. (Bug #20633, Bug #20649) * *Replication*: With the `auto_increment_increment' system variable set larger than 1, if the next generated `AUTO_INCREMENT' value would be larger than the column's maximum value, the value would be clipped down to that maximum value and inserted, even if the resulting value would not be in the generated sequence. This could cause problems for master-master replication. Now the server clips the value down to the previous value in the sequence, which correctly produces a duplicate-key error if that value already exists in the column. (Bug #20524) * *Replication*: In mixed binary logging mode, a temporary switch from statement-based logging to row-based logging occurs when storing a row that uses a function such as `UUID()' into a temporary table. However, temporary table changes are not written to the binary log under row-based logging, so the row does not exist on the slave. A subsequent select from the temporary table to a nontemporary table using statement-based logging works correctly on the master, but not on the slave where the row does not exist. Replication no longer switches back from row-based logging to statement-based logging until there are no temporary tables for the session. (Bug #20499) * *Replication*: *Note `CREATE PROCEDURE': create-procedure, *Note `CREATE FUNCTION': create-function, *Note `CREATE TRIGGER': create-trigger, and *Note `CREATE VIEW': create-view. statements containing multi-line comments (`/* ... */') could not be replicated. (Bug #20438) * *Replication*: A stored procedure that used `LAST_INSERT_ID()' did not replicate properly using statement-based binary logging. (Bug #20339) * *Replication*: When using row based replication, a *Note `CREATE TABLE ... SELECT': create-table. statement was replicated, even if the table creation failed on the master (for example, due to a duplicate key failure). (Bug #20265) * *Replication*: If a table on a slave server had a higher `AUTO_INCREMENT' counter than the corresponding master table (even though all rows of the two tables were identical), in some cases *Note `REPLACE': replace. or *Note `INSERT ... ON DUPLICATE KEY UPDATE': insert-on-duplicate. would not replicate properly using statement-based logging. (Different values would be inserted on the master and slave.) (Bug #20188) * *Replication*: Shutting down a slave in a replication scenario where temporary tables are in use would cause the slave to produce a core dump. (Bug #19881) * *Replication*: The effect of a stored function or trigger that caused `AUTO_INCREMENT' values to be generated for multiple tables was not logged properly if statement-based logging was used. Only the first table's value was logged, causing replication to fail. Under mixed logging format, this is dealt with by switching to row-based logging for the function or trigger. For statement-based logging, this remains a problem. (Bug #19630) * *Replication*: For row-based replication, the *Note `BINLOG': binlog. statement did not lock tables properly, causing a crash for some table types. (Bug #19459) * *Replication*: Column names supplied for a view created on a master server could be lost on a slave server. (Bug #19419) * *Replication*: The dropping of a temporary table whose name contained a backtick ('``'') character was not correctly written to the binary log, which also caused it not to be replicated correctly. (Bug #19188) * *Replication*: With row-based replication, replicating a statement to a slave where the table had additional columns relative to the master table did not work. (Bug #19069) * *Replication*: Valgrind revealed an issue with *Note `mysqld': mysqld. that was corrected: memory corruption in replication slaves when switching databases. (Bug #19022) * *Replication*: A redundant table map event could be generated in the binary log when there were no actual changes to a table being replicated. In addition, a slave failed to stop when attempting to replicate a table that did not exist on the slave. (Bug #18948) * *Replication*: Row-based replication failed when the query cache was enabled on the slave. (Bug #17620) * *Replication*: Compilation on Windows would fail if row based replication was disabled using `--without-row-based-replication'. (Bug #16837) * *Replication*: An invalid *Note `GRANT': grant. statement for which `Ok' was returned on a replication master caused an error on the slave and replication to fail. (Bug #6774) * *Disk Data*: On some platforms, *Note `ndbd': mysql-cluster-programs-ndbd. compiled with `gcc' 4 would crash when attempting to run *Note `CREATE LOGFILE GROUP': create-logfile-group. (Bug #21981) * *Disk Data*: Trying to create a Disk Data table using a nonexistent tablespace or to drop a nonexistent data file from a tablespace produced an uninformative error message. (Bug #21751) * *Disk Data*: Errors could occur when dropping a data file during a node local checkpoint. (Bug #21710) * *Disk Data*: Creating a tablespace and log file group, then attempting to restart the cluster without using the `--initial' option and without having created any Disk Data tables could cause a forced shutdown of the cluster and raise a configuration error. (Bug #21172) * *Disk Data*: *Note `mysqldump': mysqldump. did not back up tablespace or log file group information for Disk Data tables correctly. Specifically, `UNDO_BUFFER_SIZE' and `INITIAL_SIZE' values were misreported. This meant that trying to restore from such a backup would produce error 1296: `Got error 1504 'Out of logbuffer memory' from NDB'. (Bug #20809) * *Disk Data*: Running a large number of scans on Disk Data could cause subsequent scans to perform poorly. (Bug #20334) * *Disk Data*: *Note `INFORMATION_SCHEMA.FILES': files-table. records for UNDO files showed incorrect values in the `EXTENT_SIZE', `FREE_EXTENTS', and `TOTAL_EXTENTS' columns. (Bug #20073) * *Disk Data*: A data file created for one tablespace could be dropped using `ALTER TABLESPACE ... DROP DATAFILE' using a different tablespace. (Bug #20053) * *Disk Data*: Trying to create Disk Data tables when running the cluster in diskless mode caused cluster data nodes to crash. *Note*: Disk Data tables are now disabled when running in diskless mode. (Bug #20008) * *Disk Data*: An issue with disk allocation could sometimes cause a forced shutdown of the cluster when running a mix of memory and Disk Data tables. (Bug #18780) * *Disk Data*: The failure of a *Note `CREATE TABLESPACE': create-tablespace. or *Note `CREATE LOGFILE GROUP': create-logfile-group. statement did not revert all changes made prior to the point of failure. (Bug #16341) * *Cluster Replication*: One or more of the *Note `mysqld': mysqld. processes could fail when subjecting a Cluster replication setup with multiple *Note `mysqld': mysqld. processes on both the master and slave clusters to high loads. (Bug #19768) * *Cluster API*: The `storage/ndb' directory was missing from the server binary distribution, making it impossible to compile *Note `NDB': mysql-cluster. API and MGM API applications. This directory can be found as `/usr/include/storage/ndb' after installing that distribution. (Bug #21955) * *Cluster API*: Invoking the MGM API function `ndb_mgm_listen_event()' (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-listen-event.html) caused a memory leak. (Bug #21671) * *Cluster API*: The inclusion of `my_config.h' in `NdbApi.h' required anyone wishing to write NDB API applications against MySQL 5.1 to have a complete copy of the 5.1 sources. (Bug #21253) * *Cluster API*: The MGM API function `ndb_logevent_get_fd()' was not implemented. (Bug #21129) * *Cluster API*: The `NdbOperation::getBlobHandle()' method, when called with the name of a nonexistent column, caused a segmentation fault. (Bug #21036) * *Cluster API*: `NdbScanOperation::readTuples()' and `NdbIndexScanOperation::readTuples()' ignored the BATCH parameter. (Bug #20252) * *Note `ALTER EVENT': alter-event. statements including only a `COMMENT' clause failed with a syntax error on two platforms: Linux for S/390, and OS X 10.4 for 64-bit PowerPC. (Bug #23423) * When `event_scheduler' was set to `DISABLED', its value was not displayed correctly by *Note `SHOW VARIABLES': show-variables. or `SELECT @@global.event_scheduler'. (Bug #22662) * *Note `ALTER EVENT': alter-event. in the body of a stored procedure led to a crash when the procedure was called. This affected only those *Note `ALTER EVENT': alter-event. statements which changed the interval of the event. (Bug #22397) * The optimizer could make an incorrect index choice for indexes with a skewed key distribution. (Bug #22393) * Deleting entries from a large `MyISAM' index could cause index corruption when it needed to shrink. Deletes from an index can happen when a record is deleted, when a key changes and must be moved, and when a key must be un-inserted because of a duplicate key. This can also happen in *Note `REPAIR TABLE': repair-table. when a duplicate key is found and in *Note `myisamchk': myisamchk. when sorting the records by an index. (Bug #22384) * Instance Manager had a race condition involving ` mysqld' PID file removal. (Bug #22379) * yaSSL had a conflicting definition for `socklen_t' on hurd-i386 systems. (Bug #22326) * Conversion of values inserted into a *Note `BIT': numeric-types. column could affect adjacent columns. (Bug #22271) * Some Linux-x86_64-icc packages (of previous releases) mistakenly contained 32-bit binaries. Only `ICC' builds are affected, not `gcc' builds. Solaris and FreeBSD x86_64 builds are not affected. (Bug #22238) * `mysql_com.h' unnecessarily referred to the `ulong' type. (Bug #22227) * The source distribution would not build on Windows due to a spurious dependency on `ib_config.h'. (Bug #22224) * Execution of a prepared statement that uses an `IN' subquery with aggregate functions in the `HAVING' clause could cause a server crash. (Bug #22085) * The `CSV' storage engine failed to detect some table corruption. (Bug #22080) * Using `GROUP_CONCAT()' on the result of a subquery in the `FROM' clause that itself used `GROUP_CONCAT()' could cause a server crash. (Bug #22015) * Running *Note `SHOW MASTER LOGS': show-binary-logs. at the same time as binary log files were being switched would cause `mysqld' to hang. (Bug #21965) * `libmysqlclient' defined a symbol `BN_bin2bn' which belongs to OpenSSL. This could break applications that also linked against OpenSSL's `libcrypto' library. The fix required correcting an error in a build script that was failing to add rename macros for some functions. (Bug #21930) * `character_set_results' can be `NULL' to signify `no conversion,' but some code did not check for `NULL', resulting in a server crash. (Bug #21913) * A misleading error message was displayed when attempting to define a unique key that was not valid for a partitioned table. (Bug #21862) * A query that used `GROUP BY' and an `ALL' or `ANY' quantified subquery in a `HAVING' clause could trigger an assertion failure. (Bug #21853) * An `InnoDB' mutex was not aquired and released under the same condition, leading to deadlock in some rare situations involving XA transactions. (Bug #21833) * A `NUL' byte within a prepared statement string caused the rest of the string not to be written to the query log, permitting logging to be bypassed. (Bug #21813) * `COUNT(*)' queries with `ORDER BY' and `LIMIT' could return the wrong result. *Note*: This problem was introduced by the fix for Bug#9676, which limited the rows stored in a temporary table to the `LIMIT' clause. This optimization is not applicable to nongroup queries with aggregate functions. The current fix disables the optimization in such cases. (Bug #21787) * Using *Note `DROP TABLE': drop-table. with concurrent queries causes `mysqld' to crash. (Bug #21784) * *Note `INSERT ... SELECT': insert-select. sometimes generated a spurious `Column count doesn't match value count' error. (Bug #21774) * `UPGRADE' was treated as a reserved word, although it is not. (Bug #21772) * A function result in a comparison was replaced with a constant by the optimizer under some circumstances when this optimization was invalid. (Bug #21698) * Selecting from *Note `INFORMATION_SCHEMA.FILES': files-table. could crash the server. (Bug #21676) * Errors could be generated during the execution of certain prepared statements that ran queries on partitioned tables. (Bug #21658) * The presence of a subquery in the `ON' clause of a join in a view definition prevented the `MERGE' algorithm from being used for the view in cases where it should be permitted. (Bug #21646) * When records are merged from the insert buffer and the page needs to be reorganized, `InnoDB' used incorrect column length information when interpreting the records of the page. This caused a server crash due to apparent corruption of secondary indexes in `ROW_FORMAT=COMPACT' that contain prefix indexes of fixed-length columns. Data files should not be corrupted, but the crash was likely to repeat every time the server was restarted. (Bug #21638) * For character sets having a `mbmaxlen' value of 2, any *Note `ALTER TABLE': alter-table. statement changed *Note `TEXT': blob. columns to *Note `MEDIUMTEXT': blob. (Bug #21620) * *Note `mysql': mysql. displayed an empty string for `NULL' values. (Bug #21618) * Selecting from a `MERGE' table could result in a server crash if the underlying tables had fewer indexes than the `MERGE' table itself. (Bug #21617, Bug #22937) * A loaded storage engine plugin did not load after a server restart. (Bug #21610) * For *Note `INSERT ... ON DUPLICATE KEY UPDATE': insert-on-duplicate, use of `VALUES(COL_NAME)' within the *Note `UPDATE': update. clause sometimes was handled incorrectly. (Bug #21555) * Subqueries with aggregate functions but no `FROM' clause could return incorrect results. (Bug #21540) * *Note `mysqldump': mysqldump. incorrectly tried to use *Note `LOCK TABLES': lock-tables. for tables in the `INFORMATION_SCHEMA' database. (Bug #21527) * The server could crash for the second execution of a function containing a *Note `SELECT': select. statement that uses an aggregating `IN' subquery. (Bug #21493) * Memory overruns could occur for certain kinds of subqueries. (Bug #21477) * A *Note `DATE': datetime. can be represented as an integer (such as `20060101') or as a string (such as `'2006.01.01''). When a *Note `DATE': datetime. (or *Note `TIME': time.) column is compared in one *Note `SELECT': select. against both representations, constant propagation by the optimizer led to comparison of *Note `DATE': datetime. as a string against *Note `DATE': datetime. as an integer. This could result in integer comparisons such as `2006' against `20060101', erroneously producing a false result. (Bug #21475) * *Note `myisam_ftdump': myisam-ftdump. produced bad counts for common words. (Bug #21459) * Adding `ORDER BY' to a `SELECT DISTINCT(EXPR)' query could produce incorrect results. (Bug #21456) * The URL into the online manual that is printed in the stack trace message by the server was out of date. (Bug #21449) * Database and table names have a maximum length of 64 characters (even if they contain multi-byte characters), but were truncated to 64 bytes. *Note*: An additional fix was made in MySQL 5.1.18. (Bug #21432) * With `max_sp_recursion' set to 0, a stored procedure that executed a *Note `SHOW CREATE PROCEDURE': show-create-procedure. statement for itself triggered a recursion limit exceeded error, though the statement involves no recursion. (Bug #21416) * After *Note `FLUSH TABLES WITH READ LOCK': flush. followed by *Note `UNLOCK TABLES': lock-tables, attempts to drop or alter a stored routine failed with an error that the routine did not exist, and attempts to execute the routine failed with a lock conflict error. (Bug #21414) * On 64-bit Windows, a missing table generated error 1017, not the correct value of 1146. (Bug #21396) * Table aliases in multiple-table *Note `DELETE': delete. statements sometimes were not resolved. (Bug #21392) * The optimizer sometimes produced an incorrect row-count estimate after elimination of `const' tables. This resulted in choosing extremely inefficient execution plans in same cases when distribution of data in joins were skewed. (Bug #21390) * For multiple-table *Note `UPDATE': update. statements, storage engines were not notified of duplicate-key errors. (Bug #21381) * Using relative paths for `DATA DIRECTORY' or `INDEX DIRECTORY' with a partitioned table generated a warning rather than an error, and caused `junk' files to be created in the server's data directory. (Bug #21350) * Using *Note `EXPLAIN PARTITIONS': explain. with a query on a table whose partitioning expression was based on the value of a *Note `DATE': datetime. column could sometimes cause the server to crash. (Bug #21339) * The feature of being able to recover a temporary table named `#sql_ID' in `InnoDB' by creating a table named `rsql_ID_recover_innodb_tmp_table' was broken by the introduction of the new identifier encoding in MySQL 5.1.6 (Bug #21313) * It was possible for a stored routine with a non-`latin1' name to cause a stack overrun. (Bug #21311) * A query result could be sorted improperly when using `ORDER BY' for the second table in a join. (Bug #21302) * Query results could be incorrect if the `WHERE' clause contained `t.KEY_PART NOT IN (VAL_LIST)', where VAL_LIST is a list of more than 1000 constants. (Bug #21282) * Queries that used the `index_merge' and `sort_union' methods to access an `InnoDB' table could produce inaccurate results. This issue was introduced in MySQL 5.1.10 when a new handler and bitmap interface was implemented. (Bug #21277) * For user-defined functions created with *Note `CREATE FUNCTION': create-function, the `DEFINER' clause is not legal, but no error was generated. (Bug #21269) * The `SELECT' privilege was required for an insert on a view, instead of the `INSERT' privilege. (Bug #21261) This regression was introduced by Bug #20989. * *Note `mysql_config --libmysqld-libs': mysql-config. did not produce any SSL options necessary for linking `libmysqld' with SSL support enabled. (Bug #21239) * Subqueries on `INFORMATION_SCHEMA' tables could erroneously return an empty result. (Bug #21231) * *Note `mysql_upgrade': mysql-upgrade. created temporary files in a possibly insecure way. (Bug #21224) * When *Note `DROP DATABASE': drop-database. or *Note `SHOW OPEN TABLES': show-open-tables. was issued while concurrently in another connection issuing *Note `DROP TABLE': drop-table, *Note `RENAME TABLE': rename-table, `CREATE TABLE LIKE' or any other statement that required a name lock, the server crashed. (Bug #21216, Bug #19403) * The `--master-data' option for *Note `mysqldump': mysqldump. requires certain privileges, but *Note `mysqldump': mysqldump. generated a truncated dump file without producing an appropriate error message or exit status if the invoking user did not have those privileges. (Bug #21215) * Using `ALTER TABLE ... REORGANIZE PARTITIONS' to reduce the number of subpartitions to 1 caused the server to crash. (Bug #21210) * In the package of pre-built time zone tables that is available for download at `http://dev.mysql.com/downloads/timezones.html', the tables now explicitly use the `utf8' character set so that they work the same way regardless of the system character set value. (Bug #21208) * Under heavy load (executing more than 1024 simultaneous complex queries), a problem in the code that handles internal temporary tables could lead to writing beyond allocated space and memory corruption. Use of more than 1024 simultaneous cursors server wide also could lead to memory corruption. This applies to both stored procedure cursors and C API cursors. (Bug #21206) * When run with the `--use-threads' option, *Note `mysqlimport': mysqlimport. returned a random exit code. (Bug #21188) * A subquery that uses an index for both the `WHERE' and `ORDER BY' clauses produced an empty result. (Bug #21180) * Running *Note `SHOW TABLE STATUS': show-table-status. on any `InnoDB' table having at least one record could crash the server. Note that this was not due to any issue in the `InnoDB' storage engine, but rather with `AUTO_INCREMENT' handling in the partitioning code--however, the table did not have to have an `AUTO_INCREMENT' column for the bug to manifest. (Bug #21173) * Some prepared statements caused a server crash when executed a second time. (Bug #21166) * The optimizer assumed that if `(a=x AND b=x)' is true, `(a=x AND b=x) AND a=b' is also true. But that is not always so if `a' and `b' have different data types. (Bug #21159) * Some *Note `ALTER TABLE': alter-table. statements affecting a table's subpartitioning could hang. (Bug #21143) * Certain malformed *Note `INSERT': insert. statements could crash the *Note `mysql': mysql. client. (Bug #21142) * *Note `SHOW INNODB STATUS': show-innodb-status. contained some duplicate output. (Bug #21113) * `InnoDB' was slow with more than 100,000 `.idb' files. (Bug #21112) * Creating a `TEMPORARY' table with the same name as an existing table that was locked by another client could result in a lock conflict for `DROP TEMPORARY TABLE' because the server unnecessarily tried to acquire a name lock. (Bug #21096) * Performing an *Note `INSERT': insert. on a view that was defined using a *Note `SELECT': select. that specified a collation and a column alias caused the server to crash . (Bug #21086) * Incorrect results could be obtained from re-execution of a parametrized prepared statement or a stored routine with a *Note `SELECT': select. that uses `LEFT JOIN' with a second table having only one row. (Bug #21081) * *Note `ALTER VIEW': alter-view. did not retain existing values of attributes that had been originally specified but were not changed in the *Note `ALTER VIEW': alter-view. statement. (Bug #21080) * The `myisam_stats_method' variable was mishandled when set from an option file or on the command line. (Bug #21054) * With `query_cache_type' set to 0, `RESET QUERY CACHE' was very slow and other threads were blocked during the operation. Now a cache reset is faster and nonblocking. (Bug #21051) * *Note `mysql': mysql. crashed for very long arguments to the `connect' command. (Bug #21042) * When creating a table using `CREATE...SELECT' and a stored procedure, there would be a mismatch between the binary log and transaction cache which would cause a server crash. (Bug #21039) * A query using `WHERE COLUMN = CONSTANT OR COLUMN IS NULL' did not return consistent results on successive invocations. The COLUMN in each part of the `WHERE' clause could be either the same column, or two different columns, for the effect to be observed. (Bug #21019) * *Note `mysqldump': mysqldump. sometimes did not select the correct database before trying to dump views from it, resulting in an empty result set that caused *Note `mysqldump': mysqldump. to die with a segmentation fault. (Bug #21014) * Performance during an import on a table with a trigger that called a stored procedure was severely degraded. (Bug #21013) * *Note `mysql_upgrade': mysql-upgrade. produced a malformed `upgrade_defaults' file by overwriting the `[client]' group header with a `password' option. This prevented *Note `mysqlcheck': mysqlcheck. from running successfully when invoked by *Note `mysql_upgrade': mysql-upgrade. (Bug #21011) * A query of the form shown here caused the server to crash: SELECT * FROM t1 NATURAL JOIN ( t2 JOIN ( t3 NATURAL JOIN t4, t5 NATURAL JOIN t6 ) ON (t3.id3 = t2.id3 AND t5.id5 = t2.id5) ); (Bug #21007) * A *Note `SELECT': select. that used a subquery in the `FROM' clause that did not select from a table failed when the subquery was used in a join. (Bug #21002) * *Note `REPLACE ... SELECT': replace. for a view required the `INSERT' privilege for tables other than the table being modified. (Bug #20989) * `STR_TO_DATE()' sometimes would return `NULL' if the `%D' format specifier was not the last specifier in the format string. (Bug #20987) * A query using `WHERE NOT (COLUMN < ANY (SUBQUERY))' yielded a different result from the same query using the same COLUMN and SUBQUERY with `WHERE (COLUMN > ANY (SUBQUERY))'. (Bug #20975) * Under certain circumstances, `AVG(KEY_VAL)' returned a value but `MAX(KEY_VAL)' returned an empty set due to incorrect application of `MIN()/MAX()' optimization. (Bug #20954) * Closing of temporary tables failed if binary logging was not enabled. (Bug #20919) * Use of zero-length variable names caused a server crash. (Bug #20908) * Building `mysql' on Windows with `CMake' 2.4 failed to create `libmysqld' correctly. (Bug #20907) * Creating a partitioned table that used the `InnoDB' storage engine and then restarting *Note `mysqld': mysqld. with `--skip-innodb' caused MySQL to crash. (Bug #20871) * For certain queries, the server incorrectly resolved a reference to an aggregate function and crashed. (Bug #20868) * If the binary logging format was changed between the times when a locked table was modified and when it was unlocked, the binary log contents were incorrect. (Bug #20863) * It was possible to provide the `ExtractValue()' function with input containing `tags' that were not valid XML; for example, it was possible to use tag names beginning with a digit, which are not permitted by the W3C's XML 1.0 specification. Such cases caused the function to return `junk' output rather than an error message signalling the user as to the true nature of the problem. (Bug #20854) * `InnoDB' (Partitioning): Updating an `InnoDB' table using `HASH' partitioning with a composite primary key would cause the server to hang. (Bug #20852) * *Note `mysqldump': mysqldump. did not add version-specific comments around `WITH PARSER' and `TABLESPACE ... STORAGE DISK' clauses for *Note `CREATE TABLE': create-table. statements, causing dump files from servers where these features were in use to fail when loaded into older servers. (Bug #20841) * For multiple *Note `INSERT DELAYED': insert-delayed. statements executed in a batch by the delayed-insert handler thread, not all rows were written to the binary log. (Bug #20821) * The `ExtractValue()' function did not accept XML tag names containing a period (`.') character. (Bug #20795) * Using aggregate functions in subqueries yielded incorrect results under certain circumstances due to incorrect application of `MIN()'/`MAX()' optimization. (Bug #20792) * On Windows, inserting into a `MERGE' table after renaming an underlying `MyISAM' table caused a server crash. (Bug #20789) * Within stored routines, some error messages were printed incorrectly. A nonnull-terminated string was passed to a message-printing routine that expected a null-terminated string. (Bug #20778) * Merging multiple partitions having subpartitions into a single partition with subpartitions, or splitting a single partition having subpartitions into multiple partitions with subpartitions, could sometimes crash the server. These issues were associated with a failure reported in the `partition_range' test. (Bug #20767, Bug #20893, Bug #20766, Bug #21357) * Searches against a `ZEROFILL' column of a partitioned table could fail when the `ZEROFILL' column was part of the table's partitioning key. (Bug #20733) * If a column definition contained a character set declaration, but a `DEFAULT' value began with an introducer, the introducer character set was used as the column character set. (Bug #20695) * An *Note `UPDATE': update. that referred to a key column in the `WHERE' clause and activated a trigger that modified the column resulted in a loop. (Bug #20670) * Issuing a *Note `SHOW CREATE FUNCTION': show-create-function. or *Note `SHOW CREATE PROCEDURE': show-create-procedure. statement without sufficient privileges could crash the *Note `mysql': mysql. client. (Bug #20664) * *Note `INSERT DELAYED': insert-delayed. did not honor `SET INSERT_ID' or the `auto_increment_*' system variables. (Bug #20627, Bug #20830) * A buffer overwrite error in Instance Manager caused a crash. (Bug #20622) * Loading a plugin caused any an existing plugin with the same name to be lost. (Bug #20615) * A query selecting records from a single partition of a partitioned table and using `ORDER BY IC DESC' (where IC represents an indexed column) could cause errors or crash the server. (Bug #20583) * Valgrind revealed several issues with *Note `mysqld': mysqld. that were corrected: A dangling stack pointer being overwritten; possible uninitialized data in a string comparison; `syscall()' write parameter pointing to an uninitialized byte. (Bug #20579, Bug #20769, Bug #20783, Bug #20791) * If the `auto_increment_offset' setting causes MySQL to generate a value larger than the column's maximum possible value, the *Note `INSERT': insert. statement is accepted in strict SQL mode, whereas but should fail with an error. (Bug #20573) * In a view defined with `SQL SECURITY DEFINER', the `CURRENT_USER()' function returned the invoker, not the definer. (Bug #20570) * The `fill_help_tables.sql' file did not contain a `SET NAMES 'utf8'' statement to indicate its encoding. This caused problems for some settings of the MySQL character set such as `big5'. (Bug #20551) * Scheduled events that invoked stored procedures executing DDL operations on partitioned tables could crash the server. (Bug #20548) * Users who had the `SHOW VIEW' privilege for a view and privileges on one of the view's base tables could not see records in `INFORMATION_SCHEMA' tables relating to the base table. (Bug #20543) * The `fill_help_tables.sql' file did not load properly if the `ANSI_QUOTES' SQL mode was enabled. (Bug #20542) * The `MD5()', `SHA1()', and `ENCRYPT()' functions should return a binary string, but the result sometimes was converted to the character set of the argument. `MAKE_SET()' and `EXPORT_SET()' now use the correct character set for their default separators, resulting in consistent result strings which can be coerced according to normal character set rules. (Bug #20536) * If a partitioned `InnoDB' table contained an `AUTO_INCREMENT' column, a *Note `SHOW': show. statement could cause an assertion failure with more than one connection. (Bug #20493) * Using *Note `EXPLAIN PARTITIONS': explain. with a *Note `UNION': union. query could crash the server. This could occur whether or not the query actually used any partitioned tables. (Bug #20484) * Creation of a view as a join of views or tables could fail if the views or tables are in different databases. (Bug #20482) * *Note `SELECT': select. statements using `GROUP BY' against a view could have missing columns in the output when there was a trigger defined on one of the base tables for the view. (Bug #20466) * For connections that required a `SUBJECT' value, a check was performed to verify that the value was correct, but the connection was not refused if not. (Bug #20411) * *Note `mysql_upgrade': mysql-upgrade. was missing from binary MySQL distributions. (Bug #20403, Bug #18516, Bug #20556) * Some user-level errors were being written to the server's error log, which is for server errors. (Bug #20402) * Using `ALTER TABLE ... ENGINE = X', where X was not a storage engine supported by the server, would cause *Note `mysqld': mysqld. to crash. (Bug #20397) * User names have a maximum length of 16 characters (even if they contain multi-byte characters), but were being truncated to 16 bytes. (Bug #20393) * Some queries using `ORDER BY ... DESC' on subpartitioned tables could crash the server. (Bug #20389) * *Note `mysqlslap': mysqlslap. did not enable the `CLIENT_MULTI_RESULTS' flag when connecting, which is necessary for executing stored procedures. (Bug #20365) * Queries using an indexed column as the argument for the `MIN()' and `MAX()' functions following an `ALTER TABLE .. DISABLE KEYS' statement returned `Got error 124 from storage engine' until `ALTER TABLE ... ENABLE KEYS' was run on the table. (Bug #20357) * When a statement used a stored function that inserted into an `AUTO_INCREMENT' column, the generated `AUTO_INCREMENT' value was not written into the binary log, so a different value could in some cases be inserted on the slave. (Bug #20341) * Partitions were represented internally as the wrong data type, which led in some cases to failures of queries such as `SELECT COUNT(*) FROM INFORMATION_SCHEMA.PARTITIONS WHERE PARTITION_NAME = 'PARTITION_NAME''. (Bug #20340) * `PROCEDURE ANALYSE()' returned incorrect values of M `FLOAT(M, D)' and `DOUBLE(M, D)'. (Bug #20305) * Defining a table partitioned by `LIST' with a single `PARTITION ... VALUES IN (NULL)' clause could lead to server crashes, particularly with queries having `WHERE' conditions comparing the partitioning key with a constant. (Bug #20268, Bug #19801) * Partition pruning could cause incorrect results from queries, such missing rows, when the partitioning expression relied on a `BIGINT UNSIGNED' column. (Bug #20257) * For a `MyISAM' table locked with `LOCK TABLES ...WRITE', queries optimized using the `index_merge' method did not show rows inserted with the lock in place. (Bug #20256) * *Note `mysqldump': mysqldump. produced a malformed dump file when dumping multiple databases that contained views. (Bug #20221) * Running `InnoDB' with many concurrent threads could cause memory corruption and a seg fault due to a bug introduced in MySQL 5.1.11. (Bug #20213) * `SUBSTRING()' results sometimes were stored improperly into a temporary table when multi-byte character sets were used. (Bug #20204) * The thread for *Note `INSERT DELAYED': insert-delayed. rows was maintaining a separate `AUTO_INCREMENT' counter, resulting in incorrect values being assigned if `DELAYED' and non-`DELAYED' inserts were mixed. (Bug #20195) * The `--default-storage-engine' server option did not work. (Bug #20168) * For a table having `LINEAR HASH' subpartitions, the `LINEAR' keyword did not appear in the `SUBPARTITION_METHOD' column of the *Note `INFORMATION_SCHEMA.PARTITIONS': partitions-table. table. (Bug #20161) * For a *Note `DATE': datetime. parameter sent using a `MYSQL_TIME' data structure, *Note `mysql_stmt_execute()': mysql-stmt-execute. zeroed the hour, minute, and second members of the structure rather than treating them as read only. (Bug #20152) * *Note `perror': perror. crashed on Solaris due to `NULL' return value of `strerror()' system call. (Bug #20145) * *Note `FLUSH TABLES': flush. followed by a *Note `LOCK TABLES': lock-tables. statement to lock a log table and a nonlog table caused an infinite loop and high CPU use. Now *Note `FLUSH TABLES': flush. ignores log tables. To flush the log tables, use *Note `FLUSH LOGS': flush. instead. (Bug #20139) * On Linux, `libmysqlclient' when compiled with yaSSL using the `icc' compiler had a spurious dependency on C++ libraries. (Bug #20119) * For an *Note `ENUM': enum. column that used the `ucs2' character set, using *Note `ALTER TABLE': alter-table. to modify the column definition caused the default value to be lost. (Bug #20108) * For *Note `mysql': mysql, escaping with backslash sometimes did not work. (Bug #20103) * Queries on tables that were partitioned by `KEY' and had a *Note `VARCHAR': char. column as the partitioning key produced an empty result set. (Bug #20086) * A number of dependency issues in the RPM `bench' and `test' packages caused installation of these packages to fail. (Bug #20078) * Use of `MIN()' or `MAX()' with `GROUP BY' on a `ucs2' column could cause a server crash. (Bug #20076) * *Note `mysqld --flush': mysqld. failed to flush `MyISAM' table changes to disk following an *Note `UPDATE': update. statement for which no updated column had an index. (Bug #20060) * In MySQL 5.1.11, the `--with-openssl' and `--with-yassl' options were replaced by `--with-ssl'. But no message was issued if the old options were given. Now `configure' produces a message indicating that the new option should be used and exits. (Bug #20002) * When a statement is executed that does not generate any rows, an extra table map event and associated binrows event would be generated and written to the binary log. (Bug #19995) * Join conditions using index prefixes on `utf8' columns of `InnoDB' tables incorrectly ignored rows where the length of the actual value was greater than the length of the index prefix. (Bug #19960) * `AUTHORS' and `CONTRIBUTORS' were not treated as reserved words. (Bug #19939) * The `query' command for `mysqltest' did not work. (Bug #19890) * Identifiers with embedded escape characters were not handled correctly by some *Note `SHOW': show. statements due to some old code that was doing some extra unescaping. (Bug #19874) * When executing a *Note `SELECT': select. with `ORDER BY' on a view that is constructed from a *Note `SELECT': select. statement containing a stored function, the stored function was evaluated too many times. (Bug #19862) * Using *Note `SELECT': select. on a corrupt `MyISAM' table using the dynamic record format could cause a server crash. (Bug #19835) * Using cursors with `READ COMMITTED' isolation level could cause `InnoDB' to crash. (Bug #19834) * *Note `CREATE DATABASE': create-database, `RENAME DATABASE', and *Note `DROP DATABASE': drop-database. could deadlock in cases where there was a global read lock. (Bug #19815) * The yaSSL library bundled with `libmysqlclient' had some conflicts with OpenSSL. Now macros are used to rename the conflicting symbols to have a prefix of `ya'. (Bug #19810) * The `WITH CHECK OPTION' was not enforced when a *Note `REPLACE': replace. statement was executed against a view. (Bug #19789) * Multiple-table updates with `FEDERATED' tables could cause a server crash. (Bug #19773) * On 64-bit systems, use of the `cp1250' character set with a primary key column in a `LIKE' clause caused a server crash for patterns having letters in the range 128..255. (Bug #19741) * `make install' tried to build files that should already have been built by `make all', causing a failure if installation was performed using a different account than the one used for the initial build. (Bug #19738) * `InnoDB' unlocked its data directory before committing a transaction, potentially resulting in nonrecoverable tables if a server crash occurred before the commit. (Bug #19727) * An issue with yaSSL prevented Connector/J clients from connecting to the server using a certificate. (Bug #19705) * For a `MyISAM' table with a `FULLTEXT' index, compression with *Note `myisampack': myisampack. or a check with *Note `myisamchk': myisamchk. after compression resulted in table corruption. (Bug #19702) * The `ENGINE' clause was displayed in the output of *Note `SHOW CREATE TABLE': show-create-table. for partitioned tables when the SQL mode included `no_table_options'. (Bug #19695) * A cast problem caused incorrect results for prepared statements that returned float values when MySQL was compiled with `gcc' 4.0. (Bug #19694) * *Note `EXPLAIN PARTITIONS': explain. would produce illegible output in the `partitions' column if the length of text to be displayed in that column was too long. This could occur when very many partitions were defined for the table, partitions were given very long names, or due to a combination of the two. (Bug #19684) * The *Note `mysql_list_fields()': mysql-list-fields. C API function returned the incorrect table name for views. (Bug #19671) * If a query had a condition of the form ` TABLEX.KEY = TABLEY.KEY ', which participated in equality propagation and also was used for `ref' access, then early `ref'-access `NULL' filtering was not performed for the condition. This could make query execution slower. (Bug #19649) * Re-execution of a prepared multiple-table *Note `DELETE': delete. statement that involves a trigger or stored function can result in a server crash. (Bug #19634) * File size specifications for `InnoDB' data files were case sensitive. (Bug #19609) * *Note `CHECK TABLE': check-table. on a `MyISAM' table briefly cleared its `AUTO_INCREMENT' value, while holding only a read lock. Concurrent inserts to that table could use the wrong `AUTO_INCREMENT' value. *Note `CHECK TABLE': check-table. no longer modifies the `AUTO_INCREMENT' value. (Bug #19604) * Some yaSSL public function names conflicted with those from OpenSSL, causing conflicts for applications that linked against both OpenSSL and a version of `libmysqlclient' that was built with yaSSL support. The yaSSL public functions now are renamed to avoid this conflict. (Bug #19575) * In the *Note `INFORMATION_SCHEMA.FILES': files-table. table, the `INITIAL_SIZE', `MAXIMUM_SIZE', and `AUTOEXTEND_SIZE' columns incorrectly were being stored as *Note `VARCHAR': char. rather than *Note `BIGINT': numeric-types. . (Bug #19544) * `InnoDB' failed to increment the `handler_read_prev' counter. (Bug #19542) * Portions of statements related to partitioning were not surrounded by version-specific comments by `mysqldump', breaking backward compatibility for dump files. (Bug #19488) * Repeated *Note `DROP TABLE': drop-table. statements in a stored procedure could sometimes cause the server to crash. (Bug #19399) * Renaming a database to itself caused a server crash. (Bug #19392) * Race conditions on certain platforms could cause the Instance Manager to fail to initialize. (Bug #19391) * When not running in strict mode, the server failed to convert the invalid years portion of a *Note `DATE': datetime. or *Note `DATETIME': datetime. value to `'0000'' when inserting it into a table. *Note*: This fix was reverted in MySQL 5.1.18. (Bug #19370) See also Bug #25301. * Use of the `--no-pager' option caused *Note `mysql': mysql. to crash. (Bug #19363) * Multiple calls to a stored procedure that altered a partitioned `MyISAM' table would cause the server to crash. (Bug #19309) * `ALTER TABLE ... COALESCE PARTITION' did not delete the files associated with the partitions that were removed. (Bug #19305) * Adding an index to a partitioned table that had been created using `AUTO_INCREMENT = VALUE ' caused the `AUTO_INCREMENT' value to be reset. (Bug #19281) * Multiple-table *Note `DELETE': delete. statements containing a subquery that selected from one of the tables being modified caused a server crash. (Bug #19225) * The final parenthesis of a *Note `CREATE INDEX': create-index. statement occurring in a stored procedure was omitted from the binary log when the stored procedure was called. (Bug #19207) * An *Note `ALTER TABLE': alter-table. operation that does not need to copy data, when executed on a table created prior to MySQL 4.0.25, could result in a server crash for subsequent accesses to the table. (Bug #19192) * SSL connections using yaSSL on OpenBSD could fail. (Bug #19191) * `ALTER TABLE ... REBUILD PARTITION' could cause the server to hang or crash. (Bug #19122) * Using *Note `ALTER TABLE': alter-table. on a subpartitioned table caused the server to crash. (Bug #19067) * Trying to execute a query having a `WHERE' clause using `INT_COL = "STRING_VALUE" OR INT_COL IS NULL' on a partitioned table whose partitioning or subpartitioning function used the integer column INT_COL would crash the server. (Bug #19055) * A *Note `SELECT': select. with a subquery that was bound to the outer query over multiple columns returned different results when a constant was used instead of one of the dependant columns. (Bug #18925) * It was possible using `ALTER EVENT ... RENAME ...' to move an event to a database on which the user did not have the `EVENT' privilege. (Bug #18897) * When used in the *Note `DO': do. clause of a *Note `CREATE EVENT': create-event. statement, the statements *Note `CREATE EVENT': create-event, *Note `CREATE FUNCTION': create-function, and *Note `CREATE PROCEDURE': create-procedure. caused the server to crash. (These statements are not permitted inside *Note `CREATE EVENT': create-event.) (Bug #18896, Bug #16409) * *Note `BIT': numeric-types. columns in a table could cause joins that use the table to fail. (Bug #18895) * The build process incorrectly tried to overwrite `sql/lex_hash.h'. This caused the build to fail when using a shadow link tree pointing to original sources that were owned by another account. (Bug #18888) * Setting `myisam_repair_threads' caused any repair operation on a `MyISAM' table to fail to update the cardinality of indexes, instead making them always equal to 1. (Bug #18874) * The MySQL server startup script `/etc/init.d/mysql' (created from *Note `mysql.server': mysql-server.) is now marked to ensure that the system services `ypbind', `nscd', `ldap', and `NTP' are started first (if these are configured on the machine). (Bug #18810) * `InnoDB': Quoted Unicode identifiers were not handled correctly. This included names of tables, columns, and foreign keys. (Bug #18800) * Intermediate tables created during the execution of an *Note `ALTER TABLE': alter-table. statement were visible in the output of *Note `SHOW TABLES': show-tables. (Bug #18775) * `FEDERATED' tables raised invalid duplicate key errors when attempting on one server to insert rows having the same primary key values as rows that had been deleted from the linked table on the other server. (Bug #18764) * Memory used by scheduled events was not freed when the events were dropped. (Bug #18683) * The implementation for `UNCOMPRESS()' did not indicate that it could return `NULL', causing the optimizer to do the wrong thing. (Bug #18539) * Referring to a stored function qualified with the name of one database and tables in another database caused a `table doesn't exist' error. (Bug #18444) * Identifiers could not contain bytes with a value of 255, though that should be permitted as of the identifier-encoding changes made in MySQL 5.1.6. (Bug #18396) * Triggers on tables in the `mysql' database caused a server crash. Triggers for tables in this database are no longer permitted. (Bug #18361, Bug #18005) * Incorrect type aggregation for `IN()' and `CASE' expressions could lead to an incorrect result. (Bug #18360) * The length of the pattern string prefix for `LIKE' operations was calculated incorrectly for multi-byte character sets. As a result, the scanned range was wider than necessary if the prefix contained any multi-byte characters, and rows could be missing from the result set. (Bug #18359, Bug #16674) * On Windows, corrected a crash stemming from differences in Visual C runtime library routines from POSIX behavior regarding invalid file descriptors. (Bug #18275) * Linking the `pthreads' library to single-threaded MySQL libraries caused `dlopen()' to fail at runtime on HP-UX. (Bug #18267) * The source distribution failed to compile when configured with the `--with-libwrap' option. (Bug #18246) * On Windows, terminating *Note `mysqld': mysqld. with `Control+C' could result in a crash during shutdown. (Bug #18235) * Selecting data from a `MEMORY' table with a *Note `VARCHAR': char. column and a `HASH' index over it returned only the first row matched. (Bug #18233) * The use of `MIN()' and `MAX()' on columns with an index prefix produced incorrect results in some queries. (Bug #18206) * A *Note `UNION': union. over more than 128 *Note `SELECT': select. statements that use an aggregate function failed. (Bug #18175) * The optimizer did not take advantage of indexes on columns used for the second or third arguments of `BETWEEN'. (Bug #18165) * Performing `INSERT ... SELECT ... JOIN ... USING' without qualifying the column names caused `ERROR 1052 "column 'x' in field list is ambiguous"' even in cases where the column references were unambiguous. (Bug #18080) * An update that used a join of a table to itself and modified the table on both sides of the join reported the table as crashed. (Bug #18036) * Race conditions on certain platforms could cause the Instance Manager to try to restart the same instance multiple times. (Bug #18023) * Changing the definition of a *Note `DECIMAL': numeric-types. column with *Note `ALTER TABLE': alter-table. caused loss of column values. (Bug #18014) * For table-format output, *Note `mysql': mysql. did not always calculate columns widths correctly for columns containing multi-byte characters in the column name or contents. (Bug #17939) * The character set was not being properly initialized for `CAST()' with a type such as *Note `CHAR(2) BINARY': char, which resulted in incorrect results or a server crash. (Bug #17903) * Checking a `MyISAM' table (using *Note `CHECK TABLE': check-table.) having a spatial index and only one row would wrongly indicate that the table was corrupted. (Bug #17877) * For a reference to a nonexistent index in `FORCE INDEX', the error message referred to a column, not an index. (Bug #17873) * A stored procedure that created and invoked a prepared statement was not executed when called in a mysqld init-file. (Bug #17843) * It is possible to create `MERGE' tables into which data cannot be inserted (by not specifying a *Note `UNION': union. clause. However, when an insert was attempted, the error message was confusing. Now an error occurs indicating that the table is read only. (Bug #17766) * Attempting to insert a string of greater than 4096 bytes into a `FEDERATED' table resulted in the error `ERROR 1296 (HY000) at line 2: Got error 10000 'Error on remote system: 1054: Unknown column 'STRING-VALUE' from FEDERATED'. This error was raised regardless of the type of column involved (*Note `VARCHAR': char, *Note `TEXT': blob, and so on.) (Bug #17608) * If a file name was specified for the `--log' or `--log-slow-queries' options but the server was logging to tables and not files, the server produced no error message. (Bug #17599) * If the general log table reached a large enough file size (27GB), `SELECT COUNT(*)' on the table caused a server crash. (Bug #17589) * Using the extended syntax for `TRIM()'--that is, `TRIM(... FROM ...)'--in a *Note `SELECT': select. statement defining a view caused an invalid syntax error when selecting from the view. (Bug #17526) * Use of the `--prompt' option or `prompt' command caused *Note `mysql': mysql. to be unable to connect to the Instance Manager. (Bug #17485) * *Note `OPTIMIZE TABLE': optimize-table. and *Note `REPAIR TABLE': repair-table. yielded incorrect messages or warnings when used on partitioned tables. (Bug #17455) * *Note `mysqldump': mysqldump. would not dump views that had become invalid because a table named in the view definition had been dropped. Instead, it quit with an error message. Now you can specify the `--force' option to cause *Note `mysqldump': mysqldump. to keep going and write an SQL comment containing the view definition to the dump output. (Bug #17371) * `N'xxx'' and `_utf8'xxx'' were not treated as equivalent because `N'xxx'' failed to unescape backslashes (`\') and doubled apostrophe/single quote characters (`'''). (Bug #17313) * Following a failed attempt to add an index to an `ARCHIVE' table, it was no longer possible to drop the database in which the table had been created. (Bug #17310) * Assignments of values to variables of type *Note `TEXT': blob. were handled incorrectly in stored routines. (Bug #17225) * Views created from prepared statements inside of stored procedures were created with a definition that included both `SQL_CACHE' and `SQL_NO_CACHE'. (Bug #17203) * *Note `mysqldump': mysqldump. wrote an extra pair of *Note `DROP DATABASE': drop-database. and *Note `CREATE DATABASE': create-database. statements if run with the `--add-drop-database' option and the database contained views. (Bug #17201) * A `Table ... doesn't exist' error could occur for statements that called a function defined in another database. (Bug #17199) * A prepared statement that altered partitioned table within a stored procedure failed with the error `Unknown prepared statement handler'. (Bug #17138) * *Note `myisam_ftdump': myisam-ftdump. would fail when trying to open a MyISAM index file that you did not have write permissions to access, even though the command would only be reading from the file. (Bug #17122) * *Note `ALTER TABLE': alter-table. on a table created prior to 5.0.3 would cause table corruption if the *Note `ALTER TABLE': alter-table. did one of the following: * Change the default value of a column. * Change the table comment. * Change the table password. (Bug #17001) * For statements that have a `DEFINER' clause such as *Note `CREATE TRIGGER': create-trigger. or *Note `CREATE VIEW': create-view, long user names or host names could cause a buffer overflow. (Bug #16899) * The `PASSWORD()' function returned invalid results when used in some *Note `UNION': union. queries. (Bug #16881) * `ORDER BY RAND() LIMIT 1' always set a user variable to the last possible value from the table. (Bug #16861) * Queries containing a subquery that used aggregate functions could return incorrect results. (Bug #16792) * Concatenating the results of multiple constant subselects produced incorrect results. (Bug #16716) * When performing a `GROUP_CONCAT()', the server transformed *Note `BLOB': blob. columns *Note `VARCHAR': char. columns, which could cause erroneous results when using Connector/J and possibly other MySQL APIs. (Bug #16712) * Stored procedures did not use the character set defined for the database in which they were created. (Bug #16676) * Some server errors were not reported to the client, causing both to try to read from the connection until a hang or crash resulted. (Bug #16581) * If the files for an open table were removed at the OS level (external to the server), the server exited with an assertion failure. (Bug #16532) * On Windows, a definition for *Note `mysql_set_server_option()': mysql-set-server-option. was missing from the C client library. (Bug #16513) * *Note `mysqlcheck': mysqlcheck. tried to check views instead of ignoring them. (Bug #16502) * Updating a column of a `FEDERATED' table to `NULL' sometimes failed. (Bug #16494) * For *Note `SELECT ... FOR UPDATE': select. statements that used `DISTINCT' or `GROUP BY' over all key parts of a unique index (or primary key), the optimizer unnecessarily created a temporary table, thus losing the linkage to the underlying unique index values. This caused a `Result set not updatable' error. (The temporary table is unnecessary because under these circumstances the distinct or grouped columns must also be unique.) (Bug #16458) * A scheduled event that took longer to execute than the length of time scheduled between successive executions could `skip' executions. For example, an event defined with `EVERY 1 SECOND'--but which required longer than 1 second to complete--might be executed only once every 2 seconds. (Bug #16417) * A subselect used in the `ON SCHEDULE' clause of a *Note `CREATE EVENT': create-event. or *Note `ALTER EVENT': alter-event. statement caused the server to crash, rather than producing an error as expected. (Bug #16394) * Grant table modifications sometimes did not refresh the in-memory tables if the host name was `''' or not specified. (Bug #16297) * A subquery in the `WHERE' clause of the outer query and using `IN' and `GROUP BY' returned an incorrect result. (Bug #16255) * A query could produce different results with and without and index, if the `WHERE' clause contained a range condition that used an invalid *Note `DATETIME': datetime. constant. (Bug #16249) * `TIMESTAMPDIFF()' examined only the date and ignored the time when the requested difference unit was months or quarters. (Bug #16226) * Using tables from MySQL 4.x in MySQL 5.x, in particular those with *Note `VARCHAR': char. fields and using *Note `INSERT DELAYED': insert-delayed. to update data in the table would result in either data corruption or a server crash. (Bug #16218, Bug #17294, Bug #16611) * The value returned by a stored function returning a string value was not of the declared character set. (Bug #16211) * The `index_merge'/`Intersection' optimizer could experience a memory overrun when the number of table columns covered by an index was sufficiently large, possibly resulting in a server crash. (Bug #16201) * Row equalities (such as `WHERE (a,b) = (c,d)' were not taken into account by the optimizer, resulting in slow query execution. Now they are treated as conjunctions of equalities between row elements. (Bug #16081) * Some memory leaks in the `libmysqld' embedded server were corrected. (Bug #16017) * Values greater than 2 gigabytes used in the VALUES LESS THAN clause of a table partitioned by RANGE were treated as negative numbers. (Bug #16002) * A *Note `CREATE TABLE': create-table. that produced a `The PARTITION function returns the wrong type' error also caused an `Incorrect information in file' to be printed to `STDERR', and a junk file to be left in the database directory. (Bug #16000) * The `max_length' metadata value for columns created from `CONCAT()' could be incorrect when the collation of an argument differed from the collation of the `CONCAT()' itself. In some contexts such as *Note `UNION': union, this could lead to truncation of the column contents. (Bug #15962) * When `NOW()' was used in a `BETWEEN' clause of the definition for a view, it was replaced with a constant in the view. (Bug #15950) * The server's handling of the number of partitions or subpartitions specified in a `PARTITIONS' or `SUBPARTITIONS' clause was changed. Beginning with this release, the number of partitions must: * be a positive, nonzero integer * not have any leading zeros * not be an expression Also beginning with this version, no attempt is made to convert, truncate, or evaluate a `PARTITIONS' or `SUBPARTITIONS' value; instead, the *Note `CREATE TABLE': create-table. or *Note `ALTER TABLE': alter-table. statement containing the `PARTITIONS' or `SUBPARTITIONS' clause now fails with an appropriate error message. (Bug #15890) * Long multiple-row *Note `INSERT': insert. statements could take a very long time for some multi-byte character sets. (Bug #15811) * The C API failed to return a status message when invoking a stored procedure. (Bug #15752) * *Note `mysqlimport': mysqlimport. sends a `set @@character_set_database=binary' statement to the server, but this is not understood by pre-4.1 servers. Now *Note `mysqlimport': mysqlimport. encloses the statement within a `/*!40101 ... */' comment so that old servers will ignore it. (Bug #15690) * *Note `DELETE': delete. with `LEFT JOIN' for `InnoDB' tables could crash the server if `innodb_locks_unsafe_for_binlog' was enabled. (Bug #15650) * `BIN()', `OCT()', and `CONV()' did not work with BIT values. (Bug #15583) * Nested natural joins worked executed correctly when executed as a nonprepared statement could fail with an `Unknown column 'COL_NAME' in 'field list'' error when executed as a prepared statement, due to a name resolution problem. (Bug #15355) * The `MD5()' and `SHA()' functions treat their arguments as case-sensitive strings. But when they are compared, their arguments were compared as case-insensitive strings, which leads to two function calls with different arguments (and thus different results) compared as being identical. This can lead to a wrong decision made in the range optimizer and thus to an incorrect result set. (Bug #15351) * Invalid escape sequences in option files caused MySQL programs that read them to abort. (Bug #15328) * `SHOW GRANTS FOR CURRENT_USER' did not return definer grants when executed in `DEFINER' context (such as within a stored prodedure defined with `SQL SECURITY DEFINER'), it returned the invoker grants. (Bug #15298) * The `--collation-server' server option was being ignored. With the fix, if you choose a nondefault character set with `--character-set-server', you should also use `--collation-server' to specify the collation. (Bug #15276) * Re-executing a stored procedure with a complex stored procedure cursor query could lead to a server crash. (Bug #15217) * The server crashed if it tried to access a `CSV' table for which the data file had been removed. (Bug #15205) * When using tables containing *Note `VARCHAR': char. columns created under MySQL 4.1 with a 5.0 or later server, for some queries the metadata sent to the client could have an empty column name. (Bug #14897) * An invalid comparison between keys with index prefixes over multi-byte character fields could lead to incorrect result sets if the selected query execution plan used a range scan by an index prefix over a `UTF8' character field. This also caused incorrect results under similar circumstances with many other character sets. (Bug #14896) * When setting a column to its implicit default value as the result of inserting a `NULL' into a `NOT NULL' column as part of a multi-row insert or *Note `LOAD DATA': load-data. operation, the server returned a misleading warning message. (Bug #14770) * For *Note `BOOLEAN': numeric-types. mode full-text searches on nonindexed columns, `NULL' rows generated by a `LEFT JOIN' caused incorrect query results. (Bug #14708, Bug #25637) * The parser rejected queries that selected from a table twice using a *Note `UNION': union. within a subquery. The parser now supports arbitrary subquery, join, and parenthesis operations within `EXISTS' subqueries. A limitation still exists for scalar subqueries: If the subquery contains *Note `UNION': union, the first *Note `SELECT': select. of the *Note `UNION': union. cannot be within parentheses. For example, `SELECT (SELECT a FROM t1 UNION SELECT b FROM t2)' will work, but `SELECT ((SELECT a FROM t1) UNION (SELECT b FROM t2))' will not. (Bug #14654) * Using *Note `SELECT': select. and a table join while running a concurrent *Note `INSERT': insert. operation would join incorrect rows. (Bug #14400) * Prepared statements caused general log and server memory corruption. (Bug #14346) * The binary log lacked character set information for table names when dropping temporary tables. (Bug #14157) * `libmysqld' produced some warnings to `stderr' which could not be silenced. These warnings now are suppressed. (Bug #13717) * RPM packages had spurious dependencies on Perl modules and other programs. (Bug #13634) * `InnoDB' locking was improved by removing a gap lock for the case that you try to delete the same row twice within a transaction. (Bug #13544) * *Note `REPLACE': replace. statements caused activation of *Note `UPDATE': update. triggers, not *Note `DELETE': delete. and *Note `INSERT': insert. triggers. (Bug #13479) * The source distribution failed to compile when configured with the `--without-geometry' option. (Bug #12991) * With settings of `read_buffer_size' >= 2G and `read_rnd_buffer_size' >=2G, *Note `LOAD DATA INFILE': load-data. failed with no error message or caused a server crash for files larger than 2GB. (Bug #12982) * A `B-TREE' index on a `MEMORY' table erroneously reported duplicate entry error for multiple `NULL' values. (Bug #12873) * Instance Manager didn't close the client socket file when starting a new *Note `mysqld': mysqld. instance. *Note `mysqld': mysqld. inherited the socket, causing clients connected to Instance Manager to hang. (Bug #12751) * On Mac OS X, zero-byte `read()' or `write()' calls to an SMB-mounted file system could return a nonstandard return value, leading to data corruption. Now such calls are avoided. (Bug #12620) * `DATE_ADD()' and `DATE_SUB()' returned `NULL' when the result date was on the day `'9999-12-31''. (Bug #12356) * For very complex *Note `SELECT': select. statements could create temporary tables that were too large, and for which the temporary files were not removed, causing subsequent queries to fail. (Bug #11824) * After an *Note `INSERT ... ON DUPLICATE KEY UPDATE': insert-on-duplicate. statement that updated an existing row, `LAST_INSERT_ID()' could return a value not in the table. (Bug #11460) * *Note `USE': use. did not refresh database privileges when employed to re-select the current database. (Bug #10979) * The server returns a more informative error message when it attempts to open a `MERGE' table that has been defined to use non-`MyISAM' tables. (Bug #10974) * The type of the value returned by the `VARIANCE()' function varied according to the type of the input value. The function should always return a *Note `DOUBLE': numeric-types. value. (Bug #10966) * The same trigger error message was produced under two conditions: The trigger duplicated an existing trigger name, or the trigger duplicated an existing combination of action and event. Now different messages are produced for the two conditions so as to be more informative. (Bug #10946) * A locking safety check in `InnoDB' reported a spurious error `stored_select_lock_type is 0 inside ::start_stmt()' for *Note `INSERT ... SELECT': insert-select. statements in `innodb_locks_unsafe_for_binlog' mode. The safety check was removed. (Bug #10746) * *Note `CREATE USER': create-user. did not respect the 16-character user name limit. (Bug #10668) * A server or network failure with an open client connection would cause the client to hang even though the server was no longer available. As a result of this change, the `MYSQL_OPT_READ_TIMEOUT' and `MYSQL_OPT_WRITE_TIMEOUT' options for *Note `mysql_options()': mysql-options. now apply to TCP/IP connections on all platforms. Previously, they applied only to Windows. (Bug #9678) * `INSERT INTO ... SELECT ... LIMIT 1' could be slow because the `LIMIT' was ignored when selecting candidate rows. (Bug #9676) * The optimizer could produce an incorrect result after `AND' with collations such as `latin1_german2_ci', `utf8_czech_ci', and `utf8_lithianian_ci'. (Bug #9509) * The `DATA DIRECTORY' table option did not work for `TEMPORARY' tables. (Bug #8706) * A stored procedure with a `CONTINUE' handler that encountered an error continued to execute a statement that caused an error, rather with the next statement following the one that caused the error. (Bug #8153) * For ODBC compatibility, MySQL supports use of `WHERE COL_NAME IS NULL' for *Note `DATE': datetime. or *Note `DATETIME': datetime. columns that are `NOT NULL', to permit column values of `'0000-00-00'' or `'0000-00-00 00:00:00'' to be selected. However, this was not working for `WHERE' clauses in *Note `DELETE': delete. statements. (Bug #8143) * A user variable set to a value selected from an unsigned column was stored as a signed value. (Bug #7498) * The `--with-collation' option was not honored for client connections. (Bug #7192) * With `TRADITIONAL' SQL mode, assignment of out-of-bound values and rounding of assigned values was done correctly, but assignment of the same numbers represented as strings sometimes was handled differently. (Bug #6147) * On an *Note `INSERT': insert. into an updatable but noninsertable view, an error message was issued stating that the view was not updatable. Now the message says the view is not insertable-into. (Bug #5505) * *Note `EXPLAIN': explain. sometimes returned an incorrect `select_type' for a *Note `SELECT': select. from a view, compared to the `select_type' for the equivalent *Note `SELECT': select. from the base table. (Bug #5500) * Some queries that used `ORDER BY' and `LIMIT' performed quickly in MySQL 3.23, but slowly in MySQL 4.x/5.x due to an optimizer problem. (Bug #4981) * Incorporated portability fixes into the definition of `__attribute__' in `my_global.h'. (Bug #2717) * User-created tables having a name beginning with `#sql' were not visible to *Note `SHOW TABLES': show-tables. and could collide with internal temporary table names. Now they are not hidden and do not collide. (Bug #1405)  File: manual.info, Node: news-5-1-11, Next: news-5-1-10, Prev: news-5-1-12, Up: news-5-1-x D.1.57 Changes in MySQL 5.1.11 (26 May 2006) -------------------------------------------- This is a new Beta development release, fixing recently discovered bugs. This section documents all changes and bug fixes that have been applied since the last official MySQL release. If you would like to receive more fine-grained and personalized _update alerts_ about fixes that are relevant to the version and features you use, please consider subscribing to _MySQL Enterprise_ (a commercial MySQL offering). For more details, please see http://www.mysql.com/products/enterprise. *Functionality added or changed:* * *Incompatible Change*: The Event Scheduler can now be in one of three states (on, off, or the new suspended state). In addition, due to the fact that `SET GLOBAL event_scheduler;' now acts in a synchronous rather than asynchronous manner, the Event Scheduler thread can be no longer be activated or deactivated at run time. For more information regarding these changes, see *Note events-overview::. (Bug #17619) * *MySQL Cluster*: The limit of 2048 ordered indexes per cluster has been lifted. There is now no upper limit on the number of ordered indexes (including `AUTO_INCREMENT' columns) that may be used. (Bug #14509) * Added the `log_queries_not_using_indexes' system variable. (Bug #19616) * Added the `ssl_ca', `ssl_capath', `ssl_cert', `ssl_cipher', and `ssl_key' system variables, which display the values given using the corresponding command options. See *Note ssl-options::. (Bug #19606) * The `ENABLE KEYS' and `DISABLE KEYS' clauses for the *Note `ALTER TABLE': alter-table. statement are now supported for partitioned tables. (Bug #19502) * Added the `--ssl-verify-server-cert' option to MySQL client programs. This option causes the server's Common Name value in its certificate to be verified against the host name used when connecting to the server, and the connection is rejected if there is a mismatch. Added `MYSQL_OPT_SSL_VERIFY_SERVER_CERT' option for the *Note `mysql_options()': mysql-options. C API function to enable this verification. This feature can be used to prevent man-in-the-middle attacks. Verification is disabled by default. (Bug #17208) * The default for the `innodb_thread_concurrency' system variable was changed to `8'. (Bug #15868) * It is now possible to use `NEW.VAR_NAME' values within triggers as `INOUT' parameters to stored procedures. (Bug #14635) * Added the `--angel-pid-file' option to `mysqlmanager' for specifying the file in which the angel process records its process ID when `mysqlmanager' runs in daemon mode. (Bug #14106) * Previously, to build MySQL from source with SSL support enabled, you would invoke `configure' with either the `--with-openssl' or `--with-yassl' option. Those options both have been replaced by the `--with-ssl' option. By default, `--with-ssl' causes the bundled yaSSL library to be used. To select OpenSSL instead, give the option as `--with-ssl=PATH ', where PATH is the directory where the OpenSSL header files and libraries are located. * The *Note `mysql_get_ssl_cipher()': mysql-get-ssl-cipher. C API function was added. * `mysql_explain_log' (a third-party program) is no longer included in MySQL distributions. *Bugs fixed:* * *Security Fix*: An SQL-injection security hole has been found in multi-byte encoding processing. The bug was in the server, incorrectly parsing the string escaped with the *Note `mysql_real_escape_string()': mysql-real-escape-string. C API function. This vulnerability was discovered and reported by Josh Berkus and Tom Lane as part of the inter-project security collaboration of the OSDB consortium. For more information about SQL injection, please see the following text. Discussion An SQL injection security hole has been found in multi-byte encoding processing. An SQL injection security hole can include a situation whereby when a user supplied data to be inserted into a database, the user might inject SQL statements into the data that the server will execute. With regards to this vulnerability, when character set-unaware escaping is used (for example, `addslashes()' in PHP), it is possible to bypass the escaping in some multi-byte character sets (for example, SJIS, BIG5 and GBK). As a result, a function such as `addslashes()' is not able to prevent SQL-injection attacks. It is impossible to fix this on the server side. The best solution is for applications to use character set-aware escaping offered by a function such *Note `mysql_real_escape_string()': mysql-real-escape-string. However, a bug was detected in how the MySQL server parses the output of *Note `mysql_real_escape_string()': mysql-real-escape-string. As a result, even when the character set-aware function *Note `mysql_real_escape_string()': mysql-real-escape-string. was used, SQL injection was possible. This bug has been fixed. Workarounds If you are unable to upgrade MySQL to a version that includes the fix for the bug in *Note `mysql_real_escape_string()': mysql-real-escape-string. parsing, but run MySQL 5.0.1 or higher, you can use the `NO_BACKSLASH_ESCAPES' SQL mode as a workaround. (This mode was introduced in MySQL 5.0.1.) `NO_BACKSLASH_ESCAPES' enables an SQL standard compatibility mode, where backslash is not considered a special character. The result will be that queries will fail. To set this mode for the current connection, enter the following SQL statement: SET sql_mode='NO_BACKSLASH_ESCAPES'; You can also set the mode globally for all clients: SET GLOBAL sql_mode='NO_BACKSLASH_ESCAPES'; This SQL mode also can be enabled automatically when the server starts by using the command-line option `--sql-mode=NO_BACKSLASH_ESCAPES' or by setting `sql-mode=NO_BACKSLASH_ESCAPES' in the server option file (for example, `my.cnf' or `my.ini', depending on your system). (Bug #8378, CVE-2006-2753) See also Bug #8303. * *Partitioning*: *MySQL Cluster*: `SELECT MIN(UNIQUE_COLUMN)' from a Cluster table with user-defined partitioning crashed the server. (Bug #18730) * *MySQL Cluster*: *Replication*: (Replication): Memory was not freed after some *Note `ALTER TABLE': alter-table. operations, which could cause *Note `mysqld': mysqld. processes to crash. (Bug #19885) * *MySQL Cluster*: Running `ALL START' in the *Note `NDB': mysql-cluster. management client or restarting multiple nodes simultaneously could under some circumstances cause the cluster to crash. (Bug #19930) * *MySQL Cluster*: *Note `TRUNCATE TABLE': truncate-table. failed on tables having *Note `BLOB': blob. or *Note `TEXT': blob. columns with the error `Lock wait timeout exceeded'. *Note*: This issue affected both in-memory and Disk Data tables. (Bug #19201) * *MySQL Cluster*: `ALTER TABLE ENGINE=...' failed when used to change a MySQL Cluster table having no explicit primary key to use a different storage engine. *Note*: As a consequence of this fix, *Note `SHOW CREATE TABLE': show-create-table. no longer displays auto-partitioning information for *Note `NDBCLUSTER': mysql-cluster. tables. (Bug #19010) * *MySQL Cluster*: Using `stale' *Note `mysqld': mysqld. `.frm' files could cause a newly-restored cluster to fail. This situation could arise when restarting a MySQL Cluster using the `--initial' option while leaving connected *Note `mysqld': mysqld. processes running. (Bug #16875) * *MySQL Cluster*: A Cluster whose storage nodes were installed from the `MySQL-ndb-storage-* ' RPMs could not perform `CREATE' or `ALTER' operations that made use of nondefault character sets or collations. (Bug #14918) * *MySQL Cluster*: Data node failures could cause excessive CPU usage by *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. (Bug #13987) * *Replication*: The embedded server crashed with row-based replication enabled. (Bug #18518) * *Cluster Replication*: *Note `mysqld': mysqld. processes did not always detect cluster shutdown, leading to issues with Cluster replication and schema distribution. (Bug #19395) * *Cluster API*: On big-endian platforms, `NdbOperation::write_attr()' did not update 32-bit fields correctly. (Bug #19537) * *Cluster API*: The `Ndb::dropEventOperation()' method failed to clean up all objects used, which could cause memory leaks to occur. (Bug #17610) * The `Data_free' column in the output of *Note `SHOW TABLE STATUS': show-table-status. always displayed 0 for partitioned tables. (Bug #19501) * Altering a *Note `VARCHAR': char. column in a `MyISAM' table to make it longer could cause corruption of the following column. (Bug #19386) * In was not possible to invoke a stored routine containing dynamic SQL from a scheduled event. (Bug #19264) * Adding an index to a table created using partitioning by `KEY' and the `MEMORY' storage engine caused the server to crash. (Bug #19140) * Use of uninitialized user variables in a subquery in the `FROM' clause resulted in invalid entries in the binary log. (Bug #19136) * A *Note `CREATE TABLE': create-table. statement that created a table from a materialized view did not inherit default values from the underlying table. (Bug #19089) * Premature optimization of nested subqueries in the `FROM' clause that refer to aggregate functions could lead to incorrect results. (Bug #19077) * When creating a table using *Note `CREATE TABLE ... PARTITION BY ... SELECT ...': create-table-select, the partitioning clause was ignored. (Bug #19062) * For dates with 4-digit year parts less than 200, an implicit conversion to add a century was applied for date arithmetic performed with `DATE_ADD()', `DATE_SUB()', `+ INTERVAL', and `- INTERVAL'. (For example, `DATE_ADD('0050-01-01 00:00:00', INTERVAL 0 SECOND)' became `'2050-01-01 00:00:00''.) Now these operations return `NULL' rather than an incorrect non-`NULL' value. (Bug #18997) * *Note `BLOB': blob. or *Note `TEXT': blob. arguments to or values returned from stored functions were not copied properly if too long and could become garbled. (Bug #18587) * The client libraries were not compiled for position-independent code on Solaris-SPARC and AMD x86_64 platforms. (Bug #18091, Bug #13159, Bug #14202) * Returning the value of a system variable from a stored function caused a server crash. (Bug #18037) * Revised memory allocation for local objects within stored functions and triggers to avoid memory leak for repeated function or trigger invocation. (Bug #17260) * Symlinking `.mysql_history' to `/dev/null' to suppress statement history saving by *Note `mysql': mysql. did not work. (*Note `mysql': mysql. deleted the symlink and recreated `.mysql_history' as a regular file, and then wrote history to it.) (Bug #16803) * `IS_USED_LOCK()' could return an incorrect connection identifier. (Bug #16501) * Simultaneous scheduled events whose actions conflicted with one another could crash the server. (Bug #16428) * Concurrent reading and writing of privilege structures could crash the server. (Bug #16372) * The server no longer uses a signal handler for signal 0 because it could cause a crash on some platforms. (Bug #15869) * `EXPLAIN ... SELECT INTO' caused the client to hang. (Bug #15463) * *Note `CREATE TABLE ... SELECT ...': create-table. statements that used a stored function explicitly or implicitly (through a view) resulted in a `Table not locked' error. (Bug #15137, Bug #12472) * Display better error message for *Note `ALTER TABLE': alter-table. operations that will result in duplicate keys due to `AUTO_INCREMENT' resequencing. (Bug #14573) * The result from `CONV()' is a string, but was not always treated the same way as a string when converted to a real value for an arithmetic operation. (Bug #13975) * Within a trigger, *Note `SET': set-option. statements used the SQL mode of the invoking statement, not the mode in effect at trigger creation time. (Bug #6951) * Corrected several problems with the treatment of the `--log-error' option by *Note `mysqld_safe': mysqld-safe. These problems were manifest as differences from *Note `mysqld': mysqld. in error log handling. * If a file name was given for `--log-error', *Note `mysqld_safe': mysqld-safe. ignored it and did not pass it to *Note `mysqld': mysqld, which then wrote error information to `stderr' and resulted in incorrect log rotation when *Note `FLUSH LOGS': flush. was used. * `mysql_safe' now adds `.err' to the end of the file name if no extension is present (the same as *Note `mysqld': mysqld.). * *Note `mysqld_safe': mysqld-safe. treated a relative path name as relative to its own current working directory. Now it treats a relative path name as relative to the data directory (the same as *Note `mysqld': mysqld.). In addition, some argument quoting problems were corrected. (Bug #6061) * The `basedir' and `tmpdir' system variables could not be accessed using `@@VAR_NAME' syntax. (Bug #1039) * *Note `mysqld_safe': mysqld-safe. treated a relative path name as relative to its own current working directory. Now it treats a relative path name as relative to the data directory (the same as *Note `mysqld': mysqld.). * `mysql_safe' now adds `.err' to the end of the file name if no extension is present (the same as *Note `mysqld': mysqld.). * If a file name was given for `--log-error', *Note `mysqld_safe': mysqld-safe. ignored it and did not pass it to *Note `mysqld': mysqld, which then wrote error information to `stderr' and resulted in incorrect log rotation when *Note `FLUSH LOGS': flush. was used. * The patch for Bug#8303 broke the fix for Bug#8378 and was reverted. In string literals with an escape character (`\') followed by a multi-byte character that had (`\') as its second byte, the literal was not interpreted correctly. Now only next byte now is escaped, and not the entire multi-byte character. This means it is a strict reverse of the *Note `mysql_real_escape_string()': mysql-real-escape-string. function.  File: manual.info, Node: news-5-1-10, Next: news-5-1-9, Prev: news-5-1-11, Up: news-5-1-x D.1.58 Changes in MySQL 5.1.10 (Not released) --------------------------------------------- *Note*: This was an internal release only, and no binaries were published. MySQL 5.1.10 includes the patches for recently reported security vulnerabilities in the MySQL client/server protocol. We would like to thank Stefano Di Paola for finding and reporting these to us. This section documents all changes and bug fixes that have been applied since the last official MySQL release. If you would like to receive more fine-grained and personalized _update alerts_ about fixes that are relevant to the version and features you use, please consider subscribing to _MySQL Enterprise_ (a commercial MySQL offering). For more details, please see http://www.mysql.com/products/enterprise. *Functionality added or changed:* * *Security Enhancement*: Added the global `max_prepared_stmt_count' system variable to limit the total number of prepared statements in the server. This limits the potential for denial-of-service attacks based on running the server out of memory by preparing huge numbers of statements. The current number of prepared statements is available through the `prepared_stmt_count' system variable. (Bug #16365) * *MySQL Cluster*: It is now possible to restore a MySQL Cluster backup between big-endian and little-endian machines. (Bug #19255) * *MySQL Cluster*: It is now possible to perform a partial start of a cluster. That is, it is now possible to bring up the cluster without first running *Note `ndbd `--initial'': mysql-cluster-programs-ndbd. on all configured data nodes. (Bug #18606) * *MySQL Cluster*: It is now possible to install MySQL with Cluster support to a nondefault location and change the search path for font description files using either the `--basedir' or `--character-sets-dir' options. (Previously in MySQL 5.1, *Note `ndbd': mysql-cluster-programs-ndbd. searched only the default path for character sets.) * *Packaging*: The `MySQL-shared-compat-5.1.X-.i386.rpm' shared compatibility RPMs no longer contain libraries for MySQL 5.0. This avoids a conflict because the 5.0 and 5.1 libraries share the same `soname' number. They now contain libraries for MySQL 3.23, 4.0, 4.1, and 5.1. (Bug #19288) * SQL syntax for prepared statements now supports *Note `ANALYZE TABLE': analyze-table, *Note `OPTIMIZE TABLE': optimize-table, and *Note `REPAIR TABLE': repair-table. (Bug #19308) * The `ONLY_FULL_GROUP_BY' SQL mode now also applies to the `HAVING' clause. That is, columns not named in the `GROUP BY' clause cannot be used in the `HAVING' clause if not used in an aggregate function. (Bug #18739) * XPath expressions passed to the `ExtractValue()' and `UpdateXML()' functions can now include the colon character (``:''). This enables use of these functions with XML which employs namespaces. (Bug #18170) * On Windows, some names such as `nul', `prn', and `aux' could not be used as file names because they are reserved as device names. These are now permissible names in MySQL. They are encoded by appending `@@@' to the name when the server creates the corresponding file or directory. This occurs on all platforms for portability of the corresponding database object between platforms. (Bug #17870) * The bundled yaSSL library was upgraded to version 1.3.5. This improves handling of certain problems with SSL-related command options. (Bug #17737) * You must now have the `DROP' privilege to drop table partitions. (Bug #17139) * Server and clients ignored the `--sysconfdir' option that was passed to `configure'. The directory specified by this option, if set, now is used as one of the standard locations in which to look for option files. (Bug #15069) * In result set metadata, the `MYSQL_FIELD.length' value for *Note `BIT': numeric-types. columns now is reported in number of bits. For example, the value for a `BIT(9)' column is 9. (Formerly, the value was related to number of bytes.) (Bug #13601) * The following statements now cause an implicit commit: *Note `ANALYZE TABLE': analyze-table, *Note `CHECK TABLE': check-table, *Note `OPTIMIZE TABLE': optimize-table, and *Note `REPAIR TABLE': repair-table. * Added the `KEY_BLOCK_SIZE' table option and index option. This can be used in *Note `CREATE TABLE': create-table, *Note `ALTER TABLE': alter-table, and *Note `CREATE INDEX': create-index. statements to provide a hint to the storage engine about the size to use for index key blocks. The engine is permitted to change the value if necessary. * Added the `sql_big_selects' system variable to the output of *Note `SHOW VARIABLES': show-variables. * The *Note `mysql_upgrade': mysql-upgrade. command has been converted from a shell script to a C program, so it is available on non-Unix systems such as Windows. This program should be run for each MySQL upgrade. See *Note mysql-upgrade::. * Added the *Note `REFERENTIAL_CONSTRAINTS': referential-constraints-table. table to `INFORMATION_SCHEMA'. It provides information about foreign keys. * Added the `have_dynamic_loading' system variable that indicates whether the server supports dynamic loading of plugins. * Added `--debug' option to Instance Manager. * Binary distributions that include SSL support now are built using yaSSL when possible. *Bugs fixed:* * *Security Fix*: A `NUL' byte within a comment in a statement string caused the rest of the string not to be written to the query log, permitting logging to be bypassed. (Bug #17667, CVE-2006-0903) * *Security Fix*: A malicious client, using specially crafted invalid `COM_TABLE_DUMP' packets was able to trigger an exploitable buffer overflow on the server. Thanks to Stefano Di Paola for finding and reporting this bug. (CVE-2006-1518) * *Security Fix*: A malicious client, using specially crafted invalid login or `COM_TABLE_DUMP' packets was able to read uninitialized memory, which potentially, though unlikely in MySQL, could have led to an information disclosure. (, ) Thanks to Stefano Di Paola for finding and reporting this bug. (CVE-2006-1516, CVE-2006-1517) * *MySQL Cluster*: *Replication*: (Replication): Delete and update of rows in a table without a primary key failed on the slave. (Bug #17400) * *MySQL Cluster*: A 5.1.6 or newer server did not read local checkpoints recorded by any other 5.1 version, thus preventing a system restart following an upgrade. (Bug #19333) * *MySQL Cluster*: Concurrent *Note `INSERT': insert. and *Note `ROLLBACK': commit. statements from different connections could cause node failures. (Bug #19245) * *MySQL Cluster*: (Disk Data): Running an *Note `INSERT': insert. and a *Note `DELETE': delete. on a Disk Data table in the same transaction could cause a deadlock. (Bug #19244) * *MySQL Cluster*: Starting *Note `mysqld': mysqld. without `--log-bin' caused DDL statements on *Note `NDB': mysql-cluster. tables to time out. (Bug #19214) * *MySQL Cluster*: `mysql-test-run.pl' started *Note `NDB': mysql-cluster. even for test cases that did not need it. (Bug #19083) * *MySQL Cluster*: Stopping multiple nodes could cause node failure handling not to be completed. (Bug #19039) * *MySQL Cluster*: The Cluster binlog *Note `mysqld': mysqld. accepted updates even though the binary log was not set up, which could lead to updates missing from the binary log. (Bug #18932) * *MySQL Cluster*: *Note `mysqld': mysqld. could crash when attempting an update if the cluster had failed previously. (Bug #18798) * *MySQL Cluster*: An *Note `INSERT': insert. or *Note `UPDATE': update. of more than 128 bytes of data in a 4-replica cluster could cause data nodes to crash. (Bug #18622) * *MySQL Cluster*: (Disk Data): *Note `CREATE LOGFILE GROUP': create-logfile-group. accepted values other than *Note `NDB': mysql-cluster. or *Note `NDBCLUSTER': mysql-cluster. in the `ENGINE' clause. (Bug #18604) * *MySQL Cluster*: (Disk Data): Omitting the required `ENGINE' clause from a *Note `CREATE LOGFILE GROUP': create-logfile-group. or *Note `CREATE TABLESPACE': create-tablespace. statement caused the server to crash. An appropriate error message is now returned instead. (Bug #18603) * *MySQL Cluster*: Queries using `ORDER BY PKN ' failed against a `LIST'-partitioned Cluster table having a multi-column primary key, where PKN represents one of the columns making up the primary key. (Bug #18598) * *MySQL Cluster*: A simultaneous *Note `DROP TABLE': drop-table. and table update operation utilising a table scan could trigger a node failure. (Bug #18597) * *MySQL Cluster*: Fragment IDs were not logged correctly, causing `ndb_restore_log' to fail. (Bug #18594) * *MySQL Cluster*: Repeated use of the *Note `SHOW': show. and `ALL STATUS' commands in the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client could cause the `mgmd' process to crash. (Bug #18591) * *MySQL Cluster*: *Note `ndbd': mysql-cluster-programs-ndbd. sometimes failed to start with the error `Node failure handling not completed' following a graceful restart. (Bug #18550) * *MySQL Cluster*: *Note `ndb_restore': mysql-cluster-programs-ndb-restore. failed to restore a backup made from a 5.0 cluster to a 5.1 cluster. (Bug #18210) * *MySQL Cluster*: Adding an index to an unsigned integer column did not work correctly. (Bug #18133) * *MySQL Cluster*: A *Note `SELECT': select. from an *Note `NDB': mysql-cluster. table with `ORDER BY INDEXED_COLUMN ' and a `LIMIT' clause would fail following *Note `ALTER TABLE': alter-table. (Bug #18094) * *MySQL Cluster*: *Note `mysqldump': mysqldump. included in its output data from the internal `cluster' database. (Bug #17840) * *MySQL Cluster*: Backups could fail for large clusters with many tables, where the number of tables approached `MaxNoOfTables'. (Bug #17607) * *MySQL Cluster*: Some queries having a `WHERE' clause of the form `c1=val1 OR c2 LIKE 'val2'' were not evaluated correctly. (Bug #17421) * *MySQL Cluster*: An issue with *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. prevented more than 27 `mysqld' processes from connecting to a single cluster at one time. (Bug #17150) * *MySQL Cluster*: In a 2-node cluster with a node failure, restarting the node with a low value for `StartPartialTimeout' could cause the cluster to come up partitioned (`split-brain' issue). A similar issue could occur when the cluster was first started with a sufficiently low value for this parameter. (Bug #16447, Bug #18612) * *MySQL Cluster*: Performing multiple *Note `ALTER TABLE': alter-table. operations on the same *Note `NDB': mysql-cluster. table from different *Note `mysqld': mysqld. processes in the same cluster led to schema versioning errors when trying to access the table again following the restart of one of the *Note `mysqld': mysqld. processes. (Bug #16445) * *MySQL Cluster*: On systems with multiple network interfaces, data nodes would get `stuck' in startup phase 2 if the interface connecting them to the management server was working on node startup while the interface interconnecting the data nodes experienced a temporary outage. (Bug #15695) * *MySQL Cluster*: On slow networks or CPUs, the management client *Note `SHOW': show. command could sometimes erroneously show all data nodes as being master nodes belonging to nodegroup 0. (Bug #15530) * *MySQL Cluster*: Unused open handlers for tables in which the metadata had changed were not properly closed. This could result in stale results from *Note `NDB': mysql-cluster. tables following an *Note `ALTER TABLE': alter-table. statement. (Bug #13228) * *MySQL Cluster*: Uninitialized internal variables could lead to unexpected results. (Bug #11033, Bug #11034) * *MySQL Cluster*: When attempting to create an index on a *Note `BIT': numeric-types. or *Note `BLOB': blob. column, `Error 743: Unsupported character set in table or index' was returned instead of `Error 906: Unsupported attribute type in index'. * *Cluster Replication*: *Partitioning*: Attempting to create an index using multiple columns on an explicitly partitioned table in a replicated Cluster database could cause the master *Note `mysqld': mysqld. process to crash. (Bug #18284) * *Cluster Replication*: *Replication*: An issue with replication caused a *Note `mysqld': mysqld. connected to a replicated cluster to crash when entering single user mode. (Bug #18535) * *Replication*: *Note `CREATE VIEW': create-view. statements would not be replicated to the slave if the `--replicate-wild-ignore-table' rule was enabled. (Bug #18715) * *Replication*: Updating a field value when also requesting a lock with `GET_LOCK()' would cause slave servers in a replication environment to terminate. (Bug #17284) * *Replication*: The binary log would create an incorrect `DROP' query when creating temporary tables during replication. (Bug #17263) * *Disk Data*: Issuing a *Note `CREATE LOGFILE GROUP': create-logfile-group. statement during the drop of an *Note `NDB': mysql-cluster. table would cause database corruption. (Bug #19141) * *Disk Data*: Concurrent table schema operations and operations on log file groups, tablespaces, data files, or undo files could lead to data node failures. (Bug #18575) * *Cluster Replication*: Using the `--binlog-do-db' option caused problems with *Note `CREATE TABLE': create-table. on the cluster acting as the replication master. (Bug #19492) * *Cluster Replication*: When taking part in Cluster replication of tables containing *Note `BLOB': blob. columns, *Note `mysqld': mysqld. falsely reported a large memory leak in the replication buffers when there was none. (Bug #19247) * *Cluster Replication*: Trying to restore the `apply_status' table from a 5.0 cluster backup failed on a 5.1 server. (Bug #18935) * *Cluster API*: Passing a nonexistent index name to `NdbIndexScanOperation::setBound()' caused a segmentation fault. (Bug #19088) * A compatibility issue with NPTL (Native POSIX Thread Library) on Linux could result in a deadlock with *Note `FLUSH TABLES WITH READ LOCK': flush. under some conditions. (Bug #20048) * Some outer joins were incorrectly converted to inner joins. (Bug #19816) This regression was introduced by Bug #17146. * A view definition that referred to an alias in the `HAVING' clause could be saved in the `.frm' file with the alias replaced by the expression that it referred to, causing failure of subsequent `SELECT * FROM VIEW_NAME ' statements. (Bug #19573) * *Note `mysql': mysql. displayed `NULL' for strings that are empty or contain only spaces. (Bug #19564) * Selecting from a view that used `GROUP BY' on a nonconstant temporal interval (such as `DATE(COL) + INTERVAL TIME_TO_SEC(COL) SECOND' could cause a server crash. (Bug #19490) * An outer join of two views that was written using `{ OJ ... }' syntax could cause a server crash. (Bug #19396) * An issue with file handling in the partitioning code could cause *Note `mysqld': mysqld. to crash when started and then stopped within a very short period of time. (Bug #19313) * *Note `myisamchk': myisamchk. and *Note `myisam_ftdump': myisam-ftdump. should permit either table names or `.MYI' file names as arguments, but permitted only table names. (Bug #19220) * `InnoDB' could read a delete mark from its system tables incorrectly. (Bug #19217) * Executing a *Note `CREATE EVENT': create-event. statement could cause 100% CPU usage. (Bug #19170) * Eliminated some memory corruption problems that resultsd in `double free or corruption' errors and a server crash. (Bug #19154) * Attempting to set the default value of an *Note `ENUM': enum. or *Note `SET': set. column to `NULL' caused a server crash. (Bug #19145) * Index corruption could occur in cases when `key_cache_block_size' was not a multiple of the `myisam-block-size' value (for example, with `--key_cache_block_size=1536' and `--myisam-block-size=1024'). (Bug #19079) * Instance Manager now finds the version numbers, so that it works properly when the executable name isn't the same as what the Instance Manager launched (such as when wrapping a `libtool'-wrapped executable from the source tree). (Bug #19059) * Some fast *Note `ALTER TABLE': alter-table. operations (requiring no temporary table) did not work for all tables. (Bug #19011) * Successive `ALTER TABLE ... DROP PARTITION' statements on the same subpartitioned table could eventually cause the server to crash. (Bug #18962) * Creating a table in an `InnoDB' database with a column name that matched the name of an internal `InnoDB' column (including `DB_ROW_ID', `DB_TRX_ID', `DB_ROLL_PTR' and `DB_MIX_ID') would cause a crash. MySQL now returns Error 1005 `Cannot create table' with `errno' set to -1. (Bug #18934) * The parser leaked memory when its stack needed to be extended. (Bug #18930) * MySQL would not compile on Linux distributions that use the `tinfo' library. (Bug #18912) * The server attempted to flush uninitialized log tables during `SIGHUP' processing, causing a crash. (Bug #18848) * For a reference to a nonexistent stored function in a stored routine that had a `CONTINUE' handler, the server continued as though a useful result had been returned, possibly resulting in a server crash. (Bug #18787) * For single-*Note `SELECT': select. union constructs of the form (SELECT ... ORDER BY ORDER_LIST1 [LIMIT N]) ORDER BY ORDER_LIST2, the `ORDER BY' lists were concatenated and the `LIMIT' clause was ignored. (Bug #18767) * Inserts failed with duplicate key errors on a table partitioned using an `AUTO_INCREMENT' column for the partitioning key. (Bug #18753, Bug #18552) * It was possible to create a `RANGE'-partitioned table with a partition defined using the clause `VALUES LESS THAN (NULL)', even though such a partition could never contain any values whatsoever. (Bug #18752) * Delimited identifiers for partitions were not being treated the same as delimited identifiers for other database objects (such as tables and columns) with regard to permitted characters. (Bug #18750) * Conversion of a number to a `CHAR UNICODE' string returned an invalid result. (Bug #18691) * If the second or third argument to `BETWEEN' was a constant expression such as `'2005-09-01 - INTERVAL 6 MONTH' and the other two arguments were columns, `BETWEEN' was evaluated incorrectly. (Bug #18618) * `LOAD DATA FROM MASTER' would fail when trying to load the `INFORMATION_SCHEMA' database from the master, because the `INFORMATION_SCHEMA' system database would already exist on the slave. (Bug #18607) * Running an *Note `ALTER TABLE': alter-table. on a partitioned table simultaneously experiencing a high number of concurrent DML statements could crash the server. (Bug #18572) * A *Note `LOCK TABLES': lock-tables. statement that failed could cause `MyISAM' not to update table statistics properly, causing a subsequent *Note `CHECK TABLE': check-table. to report table corruption. (Bug #18544) * `mysqltest' incorrectly interpreted some `ER_XXX' error names given in the `error' command. (Bug #18495) * `InnoDB': *Note `ALTER TABLE': alter-table. to add or drop a foreign key for an `InnoDB' table had no effect. (Bug #18477) * `InnoDB' did not use a consistent read for `CREATE ... SELECT' when `innodb_locks_unsafe_for_binlog' was set. (Bug #18350) * *Note `DROP DATABASE': drop-database. did not drop stored routines associated with the database if the database name was longer than 21 characters. (Bug #18344) * A query on a table partitioned or subpartitioned by `HASH' did not display all results when using a `WHERE' condition involving a column used in the hashing expression. (Bug #18329, Bug #18423) * In `mysqltest', `--sleep=0' had no effect. Now it correctly causes `sleep' commands in test case files to sleep for 0 seconds. (Bug #18312) * The `ExtractValue()' function did not return character data within `' as expected. (Bug #18285) * A recent change caused the *Note `mysql': mysql. client not to display `NULL' values correctly and to display numeric columns left-justified rather than right-justified. The problems have been corrected. (Bug #18265) * Updates to a `MEMORY' table caused the size of `BTREE' indexes for the table to increase. (Bug #18160) * A failed *Note `ALTER TABLE': alter-table. operation could fail to clean up a temporary `.frm' file. (Bug #18129) * Event-creation statements enclosed in multi-line comments using `/*!VERSION_NUMBER ... */' syntax were not parsed correctly. (Bug #18078) * *Note `SELECT DISTINCT': select. queries sometimes returned only the last row. (Bug #18068) * `InnoDB': A *Note `DELETE': delete. followed by an *Note `INSERT': insert. and then by an *Note `UPDATE': update. on a partitioned `InnoDB' table caused subsequent queries to return incorrect results. (Bug #17992) * It was possible to use trailing spaces in the names of partitions and subpartitions. Attempting to do so now raises the error `Incorrect partition name'. (Bug #17973) * `LIKE' searches failed on a *Note `CHAR': char. column used as the partitioning column of a table partitioned by `KEY'. (Bug #17946) * Executing *Note `SELECT': select. on a large table that had been compressed within *Note `myisampack': myisampack. could cause a crash. (Bug #17917) * The `sql_big_selects' system variable was not displayed by *Note `SHOW VARIABLES': show-variables. (Bug #17849) * *Note `REPAIR TABLE': repair-table. did not restore the length for packed keys in tables created under MySQL 4.x, which caused them to appear corrupt to *Note `CHECK TABLE': check-table. but not to *Note `REPAIR TABLE': repair-table. (Bug #17810) * A range access optimizer heuristic was invalid, causing some queries to be much slower in MySQL 5.0 than in 4.0. (Bug #17379, Bug #18940) * Logging to the `mysql.general_log' and `mysql.slow_log' tables did not work for Windows builds because the `CSV' storage engine was unavailable. The `CSV' engine now is enabled in Windows builds. (Bug #17368) * If the `WHERE' condition of a query contained an `OR'-ed `FALSE' term, the set of tables whose rows cannot serve for null-complements in outer joins was determined incorrectly. This resulted in blocking possible conversions of outer joins into joins by the optimizer for such queries. (Bug #17164) * Casting a string to *Note `DECIMAL': numeric-types. worked, but casting a trimmed string (using `LTRIM()' or `RTRIM()') resulted in loss of decimal digits. (Bug #17043) * `MyISAM' table deadlock was possible if one thread issued a *Note `LOCK TABLES': lock-tables. request for write locks and then an administrative statement such as *Note `OPTIMIZE TABLE': optimize-table, if between the two statements another client meanwhile issued a multiple-table *Note `SELECT': select. for some of the locked tables. (Bug #16986) * `ALTER TABLE ... REBUILD PARTITION' returned an inaccurate error message. (Bug #16819) * Use of `--default-storage-engine=innodb' resulted in an error with the server reporting that `InnoDB' was an unknown table type. (Bug #16691) * `MySQL-shared-compat-5.1.9-0.i386.rpm' incorrectly depended on `glibc' 2.3 and could not be installed on a `glibc' 2.2 system. (Bug #16539) * The presence of multiple equalities in a condition after reading a constant table could cause the optimizer not to use an index. This resulted in certain queries being much slower than in MySQL 4.1. (Bug #16504) * Within a trigger, `CONNECTION_ID()' did not return the connection ID of the thread that caused the trigger to be activated. (Bug #16461) * The XPath `string-length()' function was not implemented for use with `ExtractValue()'. (Bug #16319) * The `ExtractValue()' function failed with a syntax error when the XPath expression used special characters such as `N~' (`N-tilde'). (Bug #16233) * The `sql_notes' and `sql_warnings' system variables were not always displayed correctly by *Note `SHOW VARIABLES': show-variables. (for example, they were displayed as `ON' after being set to `OFF'). (Bug #16195) * If the first argument to `BETWEEN' was a *Note `DATE': datetime. or *Note `TIME': time. column of a view and the other arguments were constants, `BETWEEN' did not perform conversion of the constants to the appropriate temporary type, resulting in incorrect evaluation. (Bug #16069) * After calling `FLUSH STATUS', the `max_used_connections' variable did not increment for existing connections and connections which use the thread cache. (Bug #15933) * *Note `DELETE': delete. and *Note `UPDATE': update. statements that used large `NOT IN (VALUE_LIST)' clauses could use large amounts of memory. (Bug #15872) * `InnoDB' failure to release an adaptive hash index latch could cause a server crash if the query cache was enabled. (Bug #15758) * `LAST_INSERT_ID()' in a stored function or trigger returned zero. . (Bug #15728) * The `system_time_zone' and `version_*' system variables could not be accessed using `SELECT @@VAR_NAME' syntax. (Bug #15684, Bug #12792) * If the server were built without partition support, it was possible to run partitioning-related statements with no errors or warnings, even though these statements would have no effect. Now such statements are not permitted unless the server has been compiled using the `--with-partition' option. (Bug #15561) * Use of `CONVERT_TZ()' in a view definition could result in spurious syntax or access errors. (Bug #15153) * Prevent recursive views caused by using *Note `RENAME TABLE': rename-table. on a view after creating it. (Bug #14308) * Some queries were slower in 5.0 than in 4.1 because some 4.1 cost-evaluation code had not been merged into 5.0. (Bug #14292) * Avoid trying to include `' when it doesn't work in C++ code. (Bug #13621) * Running *Note `myisampack': myisampack. followed by *Note `myisamchk': myisamchk. with the `--unpack' option would corrupt the `AUTO_INCREMENT' key. (Bug #12633) * Use of `CONVERT_TZ()' in a stored function or trigger (or in a stored procedure called from a stored function or trigger) caused an error. (Bug #11081) * When *Note `myisamchk': myisamchk. needed to rebuild a table, `AUTO_INCREMENT' information was lost. (Bug #10405)  File: manual.info, Node: news-5-1-9, Next: news-5-1-8, Prev: news-5-1-10, Up: news-5-1-x D.1.59 Changes in MySQL 5.1.9 (12 April 2006) --------------------------------------------- This is a new Beta development release, fixing recently discovered bugs. *Note*: This Beta release, as any other pre-production release, should not be installed on _production_ level systems or systems with critical data. It is good practice to back up your data before installing any new version of software. Although MySQL has worked very hard to ensure a high level of quality, protect your data by making a backup as you would for any software beta release. Please refer to our bug database at `http://bugs.mysql.com/' for more details about the individual bugs fixed in this version. This section documents all changes and bug fixes that have been applied since the last official MySQL release. If you would like to receive more fine-grained and personalized _update alerts_ about fixes that are relevant to the version and features you use, please consider subscribing to _MySQL Enterprise_ (a commercial MySQL offering). For more details, please see http://www.mysql.com/products/enterprise. *Functionality added or changed:* * *MySQL Cluster*: The *Note `NDB': mysql-cluster. storage engine now supports *Note `CREATE TABLE': create-table. statements of arbitrary length. (Previously, *Note `CREATE TABLE': create-table. statements for MySQL Cluster tables could contain a maximum of 4096 characters only.) (Bug #17813) * *MySQL Cluster*: Added the `--nowait-nodes' startup option for *Note `ndbd': mysql-cluster-programs-ndbd, making it possible to skip specified nodes without waiting for them to start when starting the cluster. See *Note mysql-cluster-programs-ndbd::. * *Note `mysqld_safe': mysqld-safe. no longer checks for a `mysqld-max' binary. Instead, *Note `mysqld_safe': mysqld-safe. nows checks only for the standard *Note `mysqld': mysqld. server unless another server binary is specified explicitly using `--mysqld' or `--mysqld-version'. If you previously relied on the implicit invocation of `mysqld-max', you should use an appropriate option now. (Bug #17861) * For partitioned tables, the output of *Note `SHOW TABLE STATUS': show-table-status. now shows in the `Engine' column the name of the storage engine used by all partitions for the table; in the `Create_options' column, the output now shows `partitioned' for a partitioned table. This change also affects the values shown in the corresponding columns of the *Note `INFORMATION_SCHEMA.TABLES': tables-table. table. (Bug #17631) * `SHOW PLUGIN' was renamed to *Note `SHOW PLUGINS': show-plugins. `SHOW PLUGIN' now is deprecated and generates a warning. (Bug #17112) * Large file support was re-enabled for the MySQL server binary for the AIX 5.2 platform. (Bug #13571) * Binary MySQL distributions now include a `mysqld-max' server, in addition to the usual *Note `mysqld': mysqld. optimized server and the *Note `mysqld-debug': mysqld. debugging server. *Bugs fixed:* * *Security Fix*: Invalid arguments to `DATE_FORMAT()' caused a server crash. Thanks to Jean-David Maillefer for discovering and reporting this problem to the Debian project and to Christian Hammers from the Debian Team for notifying us of it. (Bug #20729, CVE-2006-3469) * *Partitioning*: *MySQL Cluster*: *Note `BLOB': blob. columns did not work correctly with user-partitioned *Note `NDB': mysql-cluster. tables. (Bug #16796) * *MySQL Cluster*: An uninitialized internal variable could lead to unexpected results. (Bug #18831) * *MySQL Cluster*: *Note `TRUNCATE TABLE': truncate-table. did not reset the `AUTO_INCREMENT' counter for `MyISAM' tables when issued inside a stored procedure. *Note*: This bug did not affect `InnoDB' tables. In addition, *Note `TRUNCATE TABLE': truncate-table. does not reset the `AUTO_INCREMENT' counter for *Note `NDB': mysql-cluster. tables regardless of when it is called. (Bug #14945) See also Bug #18864. * For full-text searches in boolean mode, and when a full-text parser plugin was used, a `MYSQL_FTPARSER_PARAM::ftparser_state' could have been corrupted by recursive calls to the plugin. (Bug #18836) * `mysql_reconnect()' sent a `SET NAMES' statement to the server, even for pre-4.1 servers that do not understand the statement. (Bug #18830) * A query against a partitioned table using `WHERE COL IS NULL' could produce incorrect results given the following conditions: * The table had partitions and subpartitions * The partitioning function depended on a single column COL of one of the MySQL integer types * The partitioning function was not monotonically increasing The same issue could cause the server to crash when run in debug mode. (Bug #18659) * Partition pruning did not work properly for some kinds of partitioning and subpartitioning, with certain `WHERE' clauses. (Partitions and subpartitions that should have been marked as used were not so marked.) The error could manifest as incorrect content in *Note `EXPLAIN PARTITIONS': explain. output as well as missing rows in the results of affected queries. (Bug #18558) * Building the server using `--with-example-storage-engine' failed to enable the `EXAMPLE' storage engine in the server. (Bug #18464) * If `InnoDB' encountered a `HA_ERR_LOCK_TABLE_FULL' error and rolled back a transaction, the transaction was still written to the binary log. (Bug #18283) * Complex queries with nested joins could cause a server crash. (Bug #18279) * `COUNT(*)' on a `MyISAM' table could return different results for the base table and a view on the base table. (Bug #18237) * `EXTRACT(QUARTER FROM DATE)' returned unexpected results. (Bug #18100) * Queries using `WHERE ... IS NULL' returned incorrect results from partitioned tables. (Bug #18070) * Partition pruning did not perform correctly with partitions on `NULL', and could potentially crash the server. (Bug #18053) * *Note `MEDIUMINT': numeric-types. columns were not handled in the same way as other column types by partition pruning. Partition pruning would sometimes use inappropriate columns in performing queries. Both of these issues were rectified as part of the same bug fix. (Bug #18025) * For tables created in a MySQL 4.1 installation upgraded to MySQL 5.0 and up, multiple-table updates could update only the first matching row. (Bug #16281) * For *Note `mysql.server': mysql-server, if the `basedir' option was specified after `datadir' in an option file, the setting for `datadir' was ignored and assumed to be located under `basedir'. (Bug #16240) * Triggers created in one version of the server could not be dropped after upgrading to a newer version. (Bug #15921) * `CAST(DOUBLE AS SIGNED INT)' for large DOUBLE values outside the signed integer range truncated the result to be within range, but the result sometimes had the wrong sign, and no warning was generated. (Bug #15098) * Quoted values could not be used for partition option values. (Bug #13520) * Delimited identifiers could not be used in defining partitions. (Bug #13433) * *Note `mysql_config': mysql-config. returned incorrect libraries on `x86_64' systems. (Bug #13158) * The server was always built as though `--with-extra-charsets=complex' had been specified. (Bug #12076)  File: manual.info, Node: news-5-1-8, Next: news-5-1-7, Prev: news-5-1-9, Up: news-5-1-x D.1.60 Changes in MySQL 5.1.8 (Not released) -------------------------------------------- *Note*: This was an internal release only, and no binaries were published. *Functionality added or changed:* * *Cluster Replication*: *Incompatible Change*: The `cluster_replication' database has been renamed to `cluster'. This will effect replication between MySQL Clusters where one cluster is running MySQL 5.1.8 or later, and the other is running MySQL 5.1.7 or earlier. See *Note mysql-cluster-replication::, and especially *Note mysql-cluster-replication-schema::. * *Incompatible Change*: The semantics of `ALTER TABLE T ENGINE=X;' for partitioned tables is changed, and now means that the storage engine used for table T is changed to X. The previous statement formerly (prior to MySQL 5.1.8) meant that all partitioning was removed from the table. To remove the partitioning of a table, the syntax `ALTER TABLE T REMOVE PARTITIONING;' is introduced. The `REMOVE PARTITIONING' option can be used in combination with existing *Note `ALTER TABLE': alter-table. options such as those employed for adding or dropping columns or indexes. (Bug #17754) * *Incompatible Change*: For purposes of determining placement, `RANGE' partitioning now treats `NULL' as less than any other value. (Formerly, `NULL' was treated as equal to zero.) See *Note partitioning-handling-nulls::. (Bug #15447) * *MySQL Cluster*: The stability of `CREATE' and `DROP' operations on *Note `NDB': mysql-cluster. tables containing *Note `BLOB': blob. columns has been improved. (Bug #17761) * *MySQL Cluster*: The *Note `NDBCLUSTER': mysql-cluster. storage engine now supports *Note `INSERT IGNORE': insert. and *Note `REPLACE': replace. statements. Previously, these statements failed with an error. (Bug #17431) * *Replication*: Triggers from older servers that included no `DEFINER' clause in the trigger definition now execute with the privileges of the invoker (which on the slave is the slave SQL thread). Previously, replication slaves could not replicate such triggers. (Bug #16266) * *Replication*: The `binlog_format' system variable now can be set to a third format, `MIXED', as described in *Note replication-formats::. * *Replication*: The `binlog_format' system variable now is dynamic and can be changed at runtime, as described in *Note replication-formats::. * *Replication*: A slave server may now switch the replication format automatically. This happens when the server is running in either `STATEMENT' or `MIXED' format and encounters a row in the binary log that is written in `ROW' logging format. In that case, the slave switches to row-based replication temporarily for that event, and switches back to the previous format afterward. * *Disk Data*: You can now have only one log file group at any one time. See *Note create-logfile-group::. (Bug #16386) * Builds for Windows, Linux, and Unix (except AIX) platforms now have SSL support enabled, in the server as well as in the client libraries. Because part of the SSL code is written in C++, this does introduce dependencies on the system's C++ runtime libraries in several cases, depending on compiler specifics. (Bug #18195) * Partition pruning was made more stable, particularly in cases involving queries using tests for `NULL' values in the `WHERE' clause against subpartitioned tables which were partitioned by `LIST( SOME_FUNCTION(COL1, ... ,COLN) )'. (Bug #17891) * The output of *Note `SHOW CREATE EVENT': show-create-event. no longer qualifies the event name with the name of the schem to which the event belongs. (Bug #17714) * The following deprecated constructs now generate warnings, and they are removed as of MySQL 5.5. Where alternatives are shown, applications should be updated to use them. Existing applications that depend on the deprecated constructs should be converted to make use of the current equivalents as soon as possible. You should not employ them in new applications. * The `log_bin_trust_routine_creators' system variable (use `log_bin_trust_function_creators'). * The `table_type' system variable (use `storage_engine'). * The `TYPE' table option to specify the storage engine for *Note `CREATE TABLE': create-table. or *Note `ALTER TABLE': alter-table. (use `ENGINE'). * The `SHOW TABLE TYPES' SQL statement (use *Note `SHOW ENGINES': show-engines.). * The *Note `SHOW INNODB STATUS': show-innodb-status. and `SHOW MUTEX STATUS' SQL statements (use *Note `SHOW ENGINE INNODB STATUS': show-engine. *Note `SHOW ENGINE INNODB MUTEX': show-engine.). * The `SHOW PLUGIN' SQL statement (use *Note `SHOW PLUGINS': show-plugins.). * The `LOAD TABLE ... FROM MASTER' and `LOAD DATA FROM MASTER' SQL statements (use *Note `mysqldump': mysqldump. or *Note `mysqlhotcopy': mysqlhotcopy. to dump tables and *Note `mysql': mysql. to reload dump files). * The *Note `BACKUP TABLE': backup-table. and *Note `RESTORE TABLE': restore-table. SQL statements (use *Note `mysqldump': mysqldump. or *Note `mysqlhotcopy': mysqlhotcopy. to dump tables and *Note `mysql': mysql. to reload dump files). * *Note `TIMESTAMP(N)': datetime. data type: The ability to specify a display width of N (use without N). * The `--master-XXX' server options to set replication parameters (use the *Note `CHANGE MASTER TO': change-master-to. statement instead): `--master-host', `--master-user', `--master-password ', `--master-port', `--master-connect-retry', `--master-ssl', `--master-ssl-ca', `--master-ssl-capath', `--master-ssl-cert', `--master-ssl-cipher', `--master-ssl-key'. In addition, `SHOW BDB LOGS' and `SHOW LOGS' are removed as of MySQL 5.1.12. *Important*: `TYPE' vs `ENGINE' In order not to break legacy applications, support for `TYPE = ENGINE_NAME '--deprecated since MySQL 4.0--has been restored, but now generates a warning. _Beginning with MySQL 5.5, `TYPE = ENGINE_NAME' will no longer be available and will produce a syntax error_. _You should not use `TYPE' in any new applications, and you should immediately begin conversion of existing applications to use the `ENGINE = ENGINE_NAME' syntax instead_. (Bug #17501) * Temporary tables may no longer be partitioned. (Bug #17497) * More specific error messages are now given when attempting to create an excessive number of partitions or subpartitions. (Previously, no distinction was made between an excessive number of partitions and an excessive number of subpartitions.) (Bug #17393) * Added the `--events' option to *Note `mysqldump': mysqldump. to enable events to be included in the dump output. (Bug #16853) * For an event having no `STARTS' time specified when it was created, the `mysql.event' table's `start' column now displays the creation time rather than `NULL'. In addition, both the *Note `SHOW EVENTS': show-events. statement's `Starts' column and the `STARTS' column of the *Note `INFORMATION_SCHEMA.EVENTS': events-table. table are now empty rather than `NULL' when `STARTS' was not used in the *Note `CREATE EVENT': create-event. statement. (Bug #16537) * Event names are now case-insenstive. That is (for example), you cannot have events with the names `Myevent' and `MyEvent' belonging to the same database and definer. (Bug #16415) * Description of the `EVENT' privilege has been changed to `To create, alter, drop, and execute events'. (Bug #16412) * `MICROSECOND' intervals are no longer permitted for events. (Bug #16411) * Events no longer support times past the end of the Unix epoch. (Formerly, such dates were interpreted as being at the beginning of the Unix epoch.) (Bug #16396) * The XPath `last()' function is now implemented for use with `ExtractValue()'. (Bug #16318) * The `ExtractValue()' function with `contains()' now uses the SQL collation in making comparisons. Previously, comparisons were always binary (that is, case-sensitive). (Bug #16316) * Names of subpartitions must now be unique for an entire table, and not merely within the same partition. (Bug #15408) * Added the `--sysdate-is-now' option to *Note `mysqld': mysqld. to enable `SYSDATE()' to be treated as an alias for `NOW()'. See *Note date-and-time-functions::. (Bug #15101) * `mysqldump' now surrounds the `DEFINER', `SQL SECURITY DEFINER' and `WITH CHECK OPTION' clauses of a *Note `CREATE VIEW': create-view. statement with "not in version" comments to prevent errors in earlier versions of MySQL. (Bug #14871) * The *Note `mysql_ping()': mysql-ping. function will now retry if the `reconnect' flag is set and error `CR_SERVER_LOST' is encountered during the first attempt to ping the server. (Bug #14057) * The `mysqltest' utility now converts all `CR/LF' combinations to `LF' to enable test cases intended for Windows to work properly on UNIX-like systems. (Bug #13809) * The output from *Note `SHOW CREATE TABLE': show-create-table. is more consistent about using uppercase for keywords. Data types still are in lowercase. (Bug #10460) * The client API now attempts to reconnect using TCP/IP if the `reconnect' flag is set, as is the case with sockets. (Bug #2845) * The syntax for *Note `CREATE PROCEDURE': create-procedure. and *Note `CREATE FUNCTION': create-function. statements now includes a `DEFINER' clause. The `DEFINER' value specifies the security context to be used when checking access privileges at routine invocation time if the routine has the `SQL SECURITY DEFINER' characteristic. See *Note create-procedure::, for more information. When *Note `mysqldump': mysqldump. is invoked with the `--routines' option, it now dumps the `DEFINER' value for stored routines. *Bugs fixed:* * *Partitioning*: *MySQL Cluster*: Trying to insert a value into a nonexistent `LIST' partition of an *Note `NDB': mysql-cluster. table would cause the server to crash. *Note*: Beginning with MySQL 5.1.12, user-defined partitioning types other than `KEY' or `LINEAR KEY' were disabled for *Note `NDB': mysql-cluster. tables. (Bug #17763) * *Partitioning*: *MySQL Cluster*: A repeated *Note `SELECT': select. on a partitioned table that used the *Note `NDB': mysql-cluster. storage engine could cause the server to crash. (Bug #17390) * *MySQL Cluster*: *Replication*: `AUTO_INCREMENT' values were not propagated correctly in statement-based replication. (Bug #18208) * *MySQL Cluster*: *Replication*: Memory was mistakenly freed for `NdbRecAttr' objects during addition of an index while replicating the cluster, which could cause *Note `mysqld': mysqld. to crash. (Bug #18106) * *MySQL Cluster*: *Replication*: Row-based replication could fail with tables using *Note `VARCHAR': char. columns for primary keys and having *Note `BLOB': blob. columns. (Bug #18067) * *MySQL Cluster*: *Replication*: (Replication): The binary log on the secondary master was not being set up correctly following a table rename. (Bug #17838) * *MySQL Cluster*: Attempting to restart a node with dropped events still pending would fail. (Bug #18491) * *MySQL Cluster*: Two *Note `mysqld': mysqld. processes starting at the same time could cause a race condition. (Bug #18472) * *MySQL Cluster*: A timeout in the handling of an `ABORT' condition with more that 32 operations could yield a node failure. (Bug #18414) * *MySQL Cluster*: Two *Note `mysqld': mysqld. processes did not synchronise *Note `DROP TABLE': drop-table. binary log events correctly. (Bug #18395) * *MySQL Cluster*: A node restart immediately following a *Note `CREATE TABLE': create-table. would fail. *Important*: This fix supports 2-node Clusters only. (Bug #18385) * *MySQL Cluster*: In event of a node failure during a rollback, a `false' lock could be established on the backup for that node, which lock could not be removed without restarting the node. (Bug #18352) * *MySQL Cluster*: When multiple node restarts were attempted without permitting each restart to complete, the error message returned was `Array index out of bounds' rather than `Too many crashed replicas'. (Bug #18349) * *MySQL Cluster*: The cluster created a crashed replica of a table having an ordered index--or when logging was not enabled, of a table having a table or unique index--leading to a crash of the cluster following 8 successive restarts. (Bug #18298) * *MySQL Cluster*: Issuing a *Note `DROP LOGFILE GROUP': drop-logfile-group. statement would cause *Note `ndbd': mysql-cluster-programs-ndbd. processes to crash if MySQL had been compiled with `gcc4'. (Bug #18295) * *MySQL Cluster*: When replacing a failed master node, the replacement node could cause the cluster to crash from a buffer overflow if it had an excessively large amount of data to write to the cluster log. (Bug #18118) * *MySQL Cluster*: Insufficient `StringBuffer' memory when attempting to create a trigger caused the server to crash. (Bug #18101) * *MySQL Cluster*: Variable-length columns used as primary keys were not handled correctly. (Bug #18075) * *MySQL Cluster*: `CREATE UNIQUE INDEX' on a column containing nonunique data could cause one or more *Note `ndbd': mysql-cluster-programs-ndbd. nodes to hang or crash. (Bug #18040) * *MySQL Cluster*: Node recovery of tables with *Note `VARCHAR': char. columns using character sets was inconsistent, which could cause a number of issues, including the data nodes failing to restart and *Note `ALTER TABLE': alter-table. statements to hang. (Bug #18026) * *MySQL Cluster*: A `SELECT ... ORDER BY' query on an explicitly partitioned Cluster table with no explicit indexes would crash the server. (Bug #17899) * *MySQL Cluster*: `ALTER TABLE ... ADD INDEX' failed with `ERROR 756: Index on disk column is not supported' when run against a Disk Data table having a primary key. (Bug #17888) * *MySQL Cluster*: In some cases, a single *Note `ndbd': mysql-cluster-programs-ndbd. node failed following a system restart. (Bug #17854) * *MySQL Cluster*: A simultaneous `RENAME' of several tables was logged multiple times. (Bug #17827) * *MySQL Cluster*: Trying to perform a *Note `DELETE': delete. from an *Note `NDB': mysql-cluster. table following a *Note `LOCK TABLES': lock-tables. caused the *Note `ndbd': mysql-cluster-programs-ndbd. processes to hang. (Bug #17812) * *MySQL Cluster*: Trying to update very large partitioned tables using the *Note `NDB': mysql-cluster. storage engine sometimes caused the server to crash. (Bug #17806, Bug #16385) * *MySQL Cluster*: Using `ALTER TABLE ... ADD PARTITION' on a table partitioned by `LIST' would cause the client to hang. (Bug #17701) * *MySQL Cluster*: With a single replica, transactions waiting in the log synchronisation queue were not being restarted, causing them to be aborted. (Bug #17536) * *MySQL Cluster*: *Note `ALTER TABLE': alter-table. on a partitioned *Note `NDB': mysql-cluster. table could cause the server to crash. (Bug #17499) * *MySQL Cluster*: *Note `DELETE': delete. operations on *Note `NDB': mysql-cluster. tables could cause memory leaks. (Bug #16874) * *MySQL Cluster*: Some query cache statistics were not always correctly reported for Cluster tables. (Bug #16795) * *MySQL Cluster*: Restarting nodes were permitted to start and join the cluster too early. (Bug #16772) * *MySQL Cluster*: `UNDO_BUFFER_SIZE' was limited to 17 MB. (Bug #16657, Bug #17890) * *MySQL Cluster*: Inserting and deleting *Note `BLOB': blob. column values while a backup was in process could cause data nodes to shut down. (Bug #14028) * *Replication*: Replication of data stored in a partitioned table would cause slave servers to issue a assertion and terminate. (Bug #18436) * *Replication*: Use of *Note `TRUNCATE TABLE': truncate-table. for a `TEMPORARY' table on a master server was propagated to slaves properly, but slaves did not decrement the `Slave_open_temp_tables' counter properly. (Bug #17137) * *Replication*: Slave servers would retry the execution of an SQL statement an infinite number of times, ignoring the value `SLAVE_TRANSACTION_RETRIES' when using the NDB engine. (Bug #16228) * *Replication*: The `DEFINER' value for stored routines was not replicated. (Bug #15963) * *Disk Data*: `CREATE UNIQUE INDEX' failed with `Error 4243: Index not found'. (Bug #18039) * *Disk Data*: It was not possible to create more than 9 tablespaces. (Bug #16913) * A `SELECT ... ORDER BY ...' from a view defined using a function could crash the server. An example of such a view is `CREATE VIEW v1 AS SELECT SQRT(c1) FROM t1'. (Bug #18386) * The server would crash when *Note `SHOW STATUS': show-status. was called on a server linked with `yaSSL'. (Bug #18310) * The `ExtractValue()' function did not return an error when passed an invalid XPath string. (Bug #18172) * Using the `position()' function in the XPath argument to `ExtractValue()' crashed the server. (Bug #18171) * *Note `REPAIR TABLE': repair-table, *Note `OPTIMIZE TABLE': optimize-table, and *Note `ALTER TABLE': alter-table. operations on transactional tables (or on tables of any type on Windows) could corrupt triggers associated with those tables. (Bug #18153) * Connecting to a server with a UCS2 default character set with a client using a non-UCS2 character set crashed the server. (Bug #18004) * Using `ALTER TABLE ... REBUILD PARTITION' without specifying the name of the partition caused the server to crash, rather than reporting a syntax error. (Bug #17947) * `ALTER TABLE ... REBUILD PARTITION' with no partition name specified would crash the server. (Bug #17940) * A query with a `WHERE DATE_COLUMN > DATE_VALUE' condition failed on a table partitioned by `RANGE'. (Bug #17894) * Renaming and adding a new column to a partitioned table in the same *Note `ALTER TABLE': alter-table. statement caused the server to crash. (Bug #17772) * `MyISAM': Performing a bulk insert on a table referenced by a trigger would crash the table. (Bug #17764) * Using triggers with partitioned `InnoDB' tables led to incorrect results. (Bug #17744) * Updating a view that filters certain rows to set a filtered out row to be included in the table caused infinite loop. For example, if the view has a WHERE clause of `salary > 100' then issuing an UPDATE statement of `SET salary = 200 WHERE id = 10', caused an infinite loop. (Bug #17726) * A security enhancement in Visual Studio 8 could cause a MySQL debug server compiled with it to hang when running *Note `SELECT': select. queries against partitioned tables. (Bug #17722) * The `EXAMPLE' storage engine did not work on Windows. (Bug #17721) * `ALTER TABLE ... REORGANIZE PARTITION' failed with `Error on rename of FILENAME ...' on Windows. (Bug #17720) * The MySQL server could crash with out of memory errors when performing aggregate functions on a *Note `DECIMAL': numeric-types. column. (Bug #17602) * `NULL' values were written to the `mysql.slow_log' table incorrectly. (Bug #17600) * *Note `mysql_fix_privilege_tables': mysql-fix-privilege-tables. did not create the `mysql.plugin' table. (Bug #17568) * Improper checking of binary log statements could result in a server crash. (Bug #17457) * Rpeated invocations of a stored procedure containing a *Note `SHOW CREATE EVENT': show-create-event. statement would result in the error `Packets out of order'. (Bug #17403) * For `FEDERATED' tables, a *Note `SELECT': select. statement with an `ORDER BY' clause did not return rows in the proper order. (Bug #17377) * `SELECT ... WHERE COLUMN LIKE 'A%'', when COLUMN had a key and used the `latin2_czech_cs' collation, caused the wrong number of rows to be returned. (Bug #17374) * Calling *Note `CREATE TABLE': create-table. or *Note `ALTER TABLE': alter-table. twice on a partitioned table in a stored procedure or a prepared statement resulted in errors and sometimes server crashes. (Bug #17290) * Checks for permissions on database operations could be performed in a case-insensitive manner (a user with permissions on database `MYDATABASE' could by accident get permissions on database `myDataBase'), if the privilege data were still cached from a previous check. (Bug #17279) * Stored procedures that call UDFs and pass local string variables caused server crashes. (Bug #17261) * A problem with `NULL's and interval mapping sometimes caused incorrect results or crashes when trying to use less-than searches on partitioned tables. (Bug #17173) * Attempting to add a new partition to a table partitioned by a unique key would cause an `Out of memory' error. (Bug #17169) * Creating a table with the same name as the mapped name of another table caused a server crash. For example, if MySQL maps the table name `txu#P#p1' to `txu@0023P@0023p1' on disk, creating another table named `txu@0023P@0023p1' crashed the server. (Bug #17142) * Trying to add a partition to a table having subpartitions could crash the server. (Bug #17140) * Attempting to use a conflicting `VALUES' clause in `ALTER TABLE ... ADD PARTITION' caused the server to crash. An example of such a conflicting clause would be that uses `VALUES LESS THAN (CONSTANT)' (which indicates a range) with a table that is partitioned by `LIST'. (Bug #17127) * A failed `ALTER TABLE ... ADD PRIMARY KEY' on a partitioned table would result in bad table metadata and could possibly crash the server. (Bug #17097) * Stored routine names longer than 64 characters were silently truncated. Now the limit is properly enforced and an error occurs. (Bug #17015) * Cursors in stored routines could cause a server crash. (Bug #16887) * Triggers created without `BEGIN' and `END' clauses resulted in `You have an error in your SQL syntax' errors when dumping and replaying a binary log. (Bug #16878) * Using *Note `ALTER TABLE': alter-table. to increase the length of a `BINARY(M)' column caused column values to be padded with spaces rather than `0x00' bytes. (Bug #16857) * `ALTER TABLE ... COALESCE PARTITION' failed with an `Out of Memory' error. (Bug #16810) * `ALTER TABLE ... ADD COLUMN ... AFTER ...' failed when used on partitioned tables. (Bug #16806) * If the server was started with the `--skip-grant-tables' option, it was impossible to create a trigger or a view without explicitly specifying a `DEFINER' clause. (Bug #16777) * In a highly concurrent environment, a server crash or deadlock could result from execution of a statement that used stored functions or activated triggers coincident with alteration of the tables used by these functions or triggers. (Bug #16593) * Clients compiled from source with the `--without-readline' did not save command history from session to session. (Bug #16557) * Using `ORDER BY INTVAR ' within a stored procedure (where INTVAR is an integer variable or expression) would crash the server. *Note*: The use of an integer I in an `ORDER BY I' clause for sorting the result by the I ^th column is deprecated (and nonstandard). It should _not_ be used in new applications. See *Note select::. (Bug #16474) * Slow queries executed by scheduled events were not being written to the slow query log. (Bug #16426) * *Note `INSERT': insert. statements executed by scheduled events were not written to the general log. (Bug #16413) * Repeated invocations of a stored procedure containing a *Note `CREATE EVENT': create-event. or *Note `ALTER EVENT': alter-event. statement would crash the server. (Bug #16408) * Names of subpartitions were not displayed in the output of *Note `SHOW CREATE TABLE': show-create-table. (Bug #16370) * The `ExtractValue()' function would not accept expressions which matched element names containing an underscore character. (Bug #16320) * The `self()' XPath function was not handled correcty by `ExtractValue()'. (Bug #16315) * The `ExtractValue()' function permitted the use of the `!' character in identifiers by ignoring the illegal character. This is now correctly reported as a syntax error. (Bug #16313) * A memory leak caused warnings on slaves for certain statements that executed without warning on the master. (Bug #16175) * No error was reported when subpartitions were defined for a nonsubpartitioned table. (Bug #15961) * Character set conversion of string constants for *Note `UNION': union. of constant and table column was not done when it was safe to do so. (Bug #15949) * The *Note `mysql_close()': mysql-close. C API function leaked handles for shared-memory connections on Windows. (Bug #15846) * A *Note `SELECT': select. using a function against a nested view would crash the server. (Bug #15683) * Setting up subpartitions on at least one but not all the partitions of a partitioned table caused the server to crash. (Bug #15407) * During conversion from one character set to `ucs2', multi-byte characters with no `ucs2' equivalent were converted to multiple characters, rather than to `0x003F QUESTION MARK'. (Bug #15375) * *Note `CREATE TABLE ... PARTITION ... AS SELECT ...': create-table-select. would cause the server to crash. (Bug #15336) * When attempting to insert a `0' into a `LIST'-partitioned table that had no value-list containing `0', no error was reported. (Bug #15253) * `SELECT COUNT(*)' for a `MyISAM' table could return different results depending on whether an index was used. (Bug #14980) * Stored routines that contained only a single statement were not written properly to the dumpfile when using `mysqldump'. (Bug #14857) * Execution of a stored function or trigger which inserted data into a table while running concurrent selects on the same table could result in storing incorrect data in the query cache. (Bug #14767) * Naming a partition using the characters *Ç* or *ç* (`c-cedilla'; Unicode `00C7' or `00E7') made unreadable the table containing the partition. (Bug #14527) * Searches on indexed columns of partitioned tables failed to find all matching rows following updates of the indexed columns. (Bug #14526) * Creating a partition which depends on an expression containing a column using the UTF8 character set would cause the server to crash. (Bug #14367) * On Linux, creation of table partitions failed within a stored procedure. (Bug #14363) * Invoking more than once a prepared statement that creates a partitioned table would crash the server. (Bug #14350) * The *Note `RENAME TABLE': rename-table. statement did not move triggers to the new table. (Bug #13525) * The server would execute stored routines that had a nonexistent definer. (Bug #13198) * The length of a `VARCHAR()' column that used the `utf8' character set would increase each time the table was re-created in a stored procedure or prepared statement, eventually causing the *Note `CREATE TABLE': create-table. statement to fail. (Bug #13134) * Loading of UDFs in a statically linked MySQL caused a server crash. UDF loading is now blocked if the MySQL server is statically linked. (Bug #11835) * Setting the `myisam_repair_threads' system variable to a value larger than 1 could cause corruption of large `MyISAM' tables. (Bug #11527) * Issuing *Note `GRANT EXECUTE': grant. on a procedure would display any warnings related to the creation of the procedure. (Bug #7787)  File: manual.info, Node: news-5-1-7, Next: news-5-1-6, Prev: news-5-1-8, Up: news-5-1-x D.1.61 Changes in MySQL 5.1.7 (27 February 2006) ------------------------------------------------ *Functionality added or changed:* * *Incompatible Change*: The *Note `mysql_stmt_attr_get()': mysql-stmt-attr-get. C API function now returns a boolean rather than an unsigned int for `STMT_ATTR_UPDATE_MAX_LENGTH'. (Bug #16144) * *Incompatible Change*: Due to a change in the naming scheme for partitioning and subpartitioning files, it is not possible for the server to read partitioned tables created in previous MySQL versions. Attempting to read pre-5.1.6 partitioned tables with a MySQL 5.1.7 or later server now generates a suitable warning message. Two possible workarounds are: * 1. Create a nonpartitioned table with the same table schema using a standard *Note `CREATE TABLE': create-table. statement (that is, with no partitioning clauses) 2. Issue a `SELECT INTO' to copy the data into the nonpartitioned table before the upgrade Following the upgrade, you can partition the new table using `ALTER TABLE ... PARTITION BY ...'. * Alternatively, you can dump the table using *Note `mysqldump': mysqldump. prior to upgrading and reload it afterward with *Note `LOAD DATA': load-data. In either case, you should drop the pre-5.1.6 partitioned tables before upgrading to 5.1.6 or later. *Important*: If any partitioned tables that were created prior to MySQL 5.1.6 are present following an upgrade to MySQL 5.1.6 or later, it is also not possible to read from the *Note `INFORMATION_SCHEMA.PARTITIONS': partitions-table. table, nor will you be able to drop those tables or the database or databases in which they are located. In this event, you must: 1. Shut down *Note `mysqld': mysqld. 2. Manually delete the table, partition, and (if any) subpartition files 3. Restart the MySQL Server (Bug #13437, Bug #16695) * *Incompatible Change*: `TYPE = ENGINE_NAME ' is no longer accepted as a synonym for the `ENGINE = ENGINE_NAME ' table option. (`TYPE' has been deprecated since MySQL 4.0.) * *MySQL Cluster*: Attempting to `SELECT ... FROM INFORMATION_SCHEMA.FILES' now raises a warning in the event that the cluster has crashed. (Bug #17087) * *Replication*: In row-based replication, when executing a Rows_log_event, the associated table was locked, the rows applied and the lock released. This did not work since there are storage engines that count locks and perform an autocommit when the number of locks reach zero. Now we ensure that all table maps come before all `ROWS' events in a statement. * *Disk Data*: Status messages have been added to *Note `ndb_restore': mysql-cluster-programs-ndb-restore. to enable users to know that data files for Disk Data are being created. (Bug #16873) * *Cluster Replication*: It is now possible to replicate *Note `NDB': mysql-cluster. tables having no explicit primary key. See *Note mysql-cluster-replication::. * Creator privileges are now checked for all events before execution. (Bug #17289) * *Note `CREATE EVENT': create-event, *Note `DROP EVENT': drop-event, and *Note `ALTER EVENT': alter-event. statements are not permitted in triggers. (Bug #16410) * The SQL mode in effect at the time an event is created or altered is recorded and used during event execution. (Bug #16407) * New `charset' command added to *Note `mysql': mysql. command-line client. By typing `charset NAME' or `\C NAME' (such as `\C UTF8'), the client character set can be changed without reconnecting. (Bug #16217) * Added the `--wait-timeout' option to `mysqlmanager' to enable configuration of the timeout for dropping an inactive connection, and increased the default timeout from 30 seconds to 28,800 seconds (8 hours). (Bug #15980, Bug #12674) * All subpartitions within a given partitioned table are now guaranteed to have unique names. (Bug #15408) * *Note `mysqlimport': mysqlimport. now has a `--use-threads=N' option for loading data files in parallel using N threads. * Added the `RENAME DATABASE' statement. * Added the *Note `PROCESSLIST': processlist-table. table to `INFORMATION_SCHEMA'. * Several changes were made to make upgrades easier: * Added the *Note `mysql_upgrade': mysql-upgrade. program that checks all tables for incompatibilities with the current version of MySQL Server and repairs them if necessary. This program should be run for each MySQL upgrade (rather than *Note `mysql_fix_privilege_tables': mysql-fix-privilege-tables.). See *Note mysql-upgrade::. * Added the `FOR UPGRADE' option for the *Note `CHECK TABLE': check-table. statement. This option checks whether tables are incompatible with the current version of MySQL Server. * Added the `--check-upgrade' to *Note `mysqlcheck': mysqlcheck. that invokes *Note `CHECK TABLE': check-table. with the `FOR UPGRADE' option. Added the `--fix-db-names' and `--fix-table-names' options to *Note `mysqlcheck': mysqlcheck. * Removed the `have_isam' and `have_raid' system variables. * Added the `IN NATURAL LANGUAGE MODE' and `IN NATURAL LANGUAGE MODE WITH QUERY EXPANSION' modifiers for full-text searches. See *Note fulltext-search::. *Bugs fixed:* * *MySQL Cluster*: Creating *Note `NDB': mysql-cluster. tables containing *Note `BLOB': blob. columns but no primary key caused unpredictable behavior. (Bug #17559) * *MySQL Cluster*: Inserting the output of `REPEAT('SOME_STRING', SOME_INT)' into a *Note `BLOB': blob. column resulted in the error `Invalid blob attributes or invalid blob parts table'. (Bug #17505) * *MySQL Cluster*: *Note `ndbd': mysql-cluster-programs-ndbd. restarts could sometimes fail due to incorrect memory access. (Bug #17417) * *MySQL Cluster*: Sharing of table names containing special characters between multiple SQL nodes was not handled correctly when binary logging was enabled (a timeout error resulted). (Bug #17415) * *MySQL Cluster*: Table definitions were not shared between multiple SQL nodes in a cluster without binary logging being enabled. (Bug #17414) * *MySQL Cluster*: Cluster log file paths were truncated to 128 characters. They may now be as long as `MAX_PATH' (the maximum path length permitted by the operating system). (Bug #17411) * *MySQL Cluster*: *Note `SHOW CREATE TABLE': show-create-table. would fail when run against a table created in a different session. (Bug #17340) * *MySQL Cluster*: Following multiple forced shutdowns and restarts of data nodes, *Note `DROP DATABASE': drop-database. could fail. (Bug #17325) * *MySQL Cluster*: The `REDO' log would become corrupted (and thus unreadable) in some circumstances, due to a failure in the query handler. (Bug #17295) * *MySQL Cluster*: An *Note `UPDATE': update. with an inner join failed to match any records if both tables in the join did not have a primary key. (Bug #17257) * *MySQL Cluster*: A *Note `DELETE': delete. with a join in the `WHERE' clause failed to retrieve any records if both tables in the join did not have a primary key. (Bug #17249) * *MySQL Cluster*: *Note `CREATE TEMPORARY TABLE': create-table. of a Cluster table would fail with an `Unsupported' error or crash the server. (Bug #17210, Bug #16552) * *MySQL Cluster*: The storage engine did not permit views to be updated. (Bug #17206) * *MySQL Cluster*: When attempting to import data into an *Note `NDB': mysql-cluster. table using *Note `LOAD DATA INFILE': load-data, the server would hang in the event of a duplicate key error. (Bug #17154) * *MySQL Cluster*: In some cases, *Note `LOAD DATA INFILE': load-data. did not load all data into *Note `NDB': mysql-cluster. tables. (Bug #17081) * *MySQL Cluster*: *Note `CREATE TABLE NEW_TBL LIKE OLD_TBL;': create-table. failed when OLD_TBL used the *Note `NDB': mysql-cluster. storage engine. (Bug #17005) * *MySQL Cluster*: An unhandled resources issue could cause node failure with a `DELETE FROM TABLE' affecting thousands of rows. (Bug #16492) * *MySQL Cluster*: `UNIQUE' keys in Cluster tables were limited to 225 bytes in length. (Bug #15918) * *MySQL Cluster*: *Note `REPLACE': replace. failed when attempting to update a primary key value in a Cluster table. (Bug #14007) * *MySQL Cluster*: No error message was generated for setting `NoOfFragmentLogFiles' too low. (Bug #13966) * *MySQL Cluster*: No error message was generated for setting `MaxNoOfAttributes' too low. (Bug #13965) * *MySQL Cluster*: Performing large numbers of data manipulation statements on cluster tables using Disk Data could lead to a server crash. * *Cluster Replication*: *Replication*: Row-based replication of a cluster failed to take `--binlog-ignore-db' settings into account. (Bug #17188) * *Replication*: An *Note `ALTER DATABASE': alter-database. statement on a replication master crashed the slaves. (Bug #17521) * *Replication*: For a transaction that used `MyISAM' and `InnoDB' tables, interruption of the transaction due to a dropped connection on a master server caused slaves to lose synchrony. (Bug #16559) * *Replication*: Previously, a stored function invocation was written to the binary log as `DO FUNC_NAME()' if the invocation changes data and occurs within a nonlogged statement, or if the function invokes a stored procedure that produces an error. These invocations now are logged as `SELECT FUNC_NAME()' instead for better control over error code checking (slave servers could stop due to detecting a different error than occurred on the master). (Bug #14769) * *Replication*: *Note `BIT': numeric-types. fields were not properly handled when using row-based replication. (Bug #13418) * *Disk Data*: In some cases, a cluster using Disk Data tables could not be restarted following a normal shutdown. (Bug #16872) * *Cluster Replication*: Row-based replication was not set up correctly if a backup was already in progress. For example, connecting a *Note `mysqld': mysqld. instance to a cluster which was being backed up would result in the message `NDB: skipping setup table TBL_NAME' being written to the error log. (Bug #17459) * *Cluster Replication*: Cluster tables not having an explicit primary key could not be replicated. (Bug #14541) * Column counts were encoded incorrectly in the binary log for row-based logging format. (Bug #17678) * Data truncations on non-`UNIQUE' indexes could crash `InnoDB' when using multi-byte character sets. (Bug #17530) * Execution times for scheduled events were not calculated correctly: the last execution time was used as a base rather than the actual start time. (Bug #17494) * Creating an event and using a whitespace character other than space following the *Note `DO': do. keyword caused a server crash. (Bug #17453) * Partitioning with certain `SUBPARTITION BY HASH' clauses caused an error when querying for a partitioned column using an `IS NULL' comparison. (Bug #17430, Bug #17432) * Race conditions between event creation, dropping, and execution could result in a server crash or hang. (Bug #17373) * Trying to create a partitioned table with more than 32 attributes failed. (Bug #17179) * Attempting to add a new partition to a table partitioned by a unique key would cause an `Out of memory' error. (Bug #17169) * *Note `myisam_ftdump': myisam-ftdump. did not work for `FULLTEXT' indexes associated with a parser plugin. (Bug #17116) * On Windows platforms, some attempts to create partitioned tables from the command line would cause the `mysql' client to hang. (Bug #17082) * A *Note `SELECT': select. from the last partition of a subpartitioned table having a `UNIQUE KEY' could crash the MySQL Server. (Bug #16907) * Statements that contained Unicode characters were not logged to the log tables correctly. (Bug #16905) * A *Note `SELECT': select. on a subpartitioned table having a multiple-column `PRIMARY' or `UNIQUE KEY', and whose partitioning function used only the first column of the key, could cause *Note `mysqld': mysqld. to crash. (Bug #16901) * A *Note `RETURN': return. statement within a trigger caused a server crash. *Note `RETURN': return. is no longer permitted within triggers. To exit immediately, use *Note `LEAVE': leave-statement. (Bug #16829) * Using `REPLACE INTO' on a partitioned table having a primary key would crash the server in the event of a duplicate key error. (Bug #16782) * *Note `DROP TABLE': drop-table. would sometimes fail on a table having subpartitions that used the default storage engine. (Bug #16775) * If the query optimizer transformed a `GROUP BY' clause in a subquery, it did not also transform the `HAVING' clause if there was one, producing incorrect results. (Bug #16603) * Querying the *Note `INFORMATION_SCHEMA.PARTITIONS': partitions-table. table on a nonmax server caused a server crash. This also happened following the creation of a table with a very large number (hundreds) of partitions. (Bug #16591, Bug #17141) * *Note `SHOW CREATE EVENT': show-create-event. displayed no output. (Bug #16423) * *Note `DROP DATABASE': drop-database. did not drop events for the database. (Bug #16406) * The `mysql_fix_privilege_tables.sql' script did not properly initialize the `Event_priv' column to `'Y'' for those accounts that should have the `EVENT' privilege. (Bug #16400) * *Note `SELECT': select. with `GROUP BY' on a view could cause a server crash. (Bug #16382) * MySQL server dropped client connection for certain *Note `SELECT': select. statements against views defined that used `MERGE' algorithm. (Bug #16260) * Using an XPath expression containing `=' with `ExtractValue()' caused the server to crash. (Bug #16242) * When used with the `ExtractValue()' function, an XPath expression having no leading ``/'' character would crash the server. (Bug #16234) * Using `GROUP BY' on column used in `WHERE' clause could cause empty set to be returned. (Bug #16203) * `CAST(... AS TIME)' operations returned different results when using versus not using prepared-statement protocol. (Bug #15805) * The `SELECT' privilege was required for triggers that performed no selects. (Bug #15196) * The `UPDATE' privilege was required for triggers that performed no updates. (Bug #15166) * A statement containing `GROUP BY' and `HAVING' clauses could return incorrect results when the `HAVING' clause contained logic that returned `FALSE' for every row. (Bug #14927) * Killing a long-running query containing a subquery could cause a server crash. (Bug #14851) * `SUBSTRING_INDEX()' could yield inconsistent results when applied with the same arguments to consecutive rows in a query. (Bug #14676) * `SET sql_mode = N', where N > 31, did not work properly. (Bug #13897) * *Note `SHOW CREATE TABLE': show-create-table. produced extraneous spaces following the keywords `PRIMARY KEY'. (Bug #13883) * `InnoDB' could display an incorrect error message for a cascading update. (Bug #9680) * *Note `CHECKSUM TABLE': checksum-table. returned different values for `MyISAM' tables depending on whether the `QUICK' or `EXTENDED' option was used. (Bug #8841) * *Note `SET TRANSACTION ISOLATION LEVEL': set-transaction. acted like *Note `SET SESSION TRANSACTION ISOLATION LEVEL': set-transaction. That is, it set the isolation level for longer than the next transaction. (Bug #7955) * Repeated invocation of `my_init()' and `my_end()' caused corruption of character set data and connection failure. (Bug #6536)  File: manual.info, Node: news-5-1-6, Next: news-5-1-5, Prev: news-5-1-7, Up: news-5-1-x D.1.62 Changes in MySQL 5.1.6 (01 February 2006) ------------------------------------------------ *Functionality added or changed:* * *Incompatible Change*: Words with apostrophes are now matched in a FULLTEXT search against nonapostrophe words (for example, a search for `Jerry' will match against the term `Jerry's'). Users upgrading to this version must issue `REPAIR TABLE ... QUICK' statements for tables containing `FULLTEXT' indexes. (Bug #14194) * *Incompatible Change*: This release introduces the `TRIGGER' privilege. Previously, the `SUPER' privilege was needed to create or drop triggers. Now those operations require the `TRIGGER' privilege. This is a security improvement because you no longer need to grant users the `SUPER' privilege to enable them to create triggers. However, the requirement that the account named in a trigger's `DEFINER' clause must have the `SUPER' privilege has changed to a requirement for the `TRIGGER' privilege. After upgrading, be sure to update your grant tables by running *Note `mysql_upgrade': mysql-upgrade. This will assign the `TRIGGER' privilege to all accounts that had the `SUPER' privilege. (After updating, you might also consider whether any of those accounts no longer need the `SUPER' privilege.) If you fail to update the grant tables, triggers may fail when activated. (Bug #9412) * *Incompatible Change*: Before MySQL 5.1.6, the server writes general query log and slow query log entries to log files. As of MySQL 5.1.6, the server's logging capabilities for these logs are more flexible. Log entries can be written to log files (as before) or to the `general_log' and `slow_log' tables in the `mysql' database. If logging is enabled, either or both destinations can be selected. The `--log-output' option controls the destination or destinations of log output. See *Note log-destinations::. If logging is enabled, the default destination now is to log to tables, which differs from earlier versions. If you had the server configured for logging to log files formerly, use `--log-output=FILE' to preserve this behavior after an upgrade to MySQL 5.1.6 or higher. * *Important Change*: *MySQL Cluster*: *Replication*: Replication between MySQL Clusters is now supported. It is now also possible to replicate between a MySQL Cluster and a noncluster database. See *Note mysql-cluster-replication::, for more information. * *MySQL Cluster*: Added the `ndb_extra_logging' system variable. * *MySQL Cluster*: The *Note `NDB': mysql-cluster. storage engine now supports the *Note `CREATE INDEX': create-index. and *Note `DROP INDEX': drop-index. statements. * *Packaging*: MySQL 5.1.6 introduces some changes to distribution packaging: * Distributions include both a *Note `mysqld': mysqld. optimized server and *Note `mysqld-debug': mysqld. debugging server. There is no separate debug distribution. * There is no longer a `mysqld-max' server. (Note: This changed in MySQL 5.1.9: The `mysqld-max' server also is included in binary distributions.) * Server binaries no longer are stripped, except for RPM distributions. * Binary distributions for Unix and Unix-like systems no longer include `safe_mysqld' as a link to *Note `mysqld_safe': mysqld-safe. `safe_mysqld' has been deprecated since MySQL 4.0 and now is removed. * The *Note `mysqldump': mysqldump. utility now supports an option for dumping tablespaces. Use `-Y' or `--all-tablespaces' to enable this functionality. (Bug #16753) * Partition support is not an `engine', but it was included in the output of *Note `SHOW ENGINES': show-engines. Now it is not. The `have_partition_engine' variable was renamed to `have_partitioning'. (Bug #14355, Bug #16718) * *Note `ANALYZE TABLE': analyze-table. is now supported for partitioned tables. (Bug #13441) * Added the `--use-threads' option for *Note `mysqlslap': mysqlslap. * Queries against partitioned tables can now take advantage of partition pruning. In some cases, this can result in query execution that is an order of magnitude faster than the same query against a nonpartitioned version of the same table. * There is no longer a `mysqld-max' server. (Note: This changed in MySQL 5.1.9: The `mysqld-max' server also is included in binary distributions.) * Added the *Note `FILES': files-table. table to `INFORMATION_SCHEMA'. * Binary distributions for Unix and Unix-like systems no longer include `safe_mysqld' as a link to *Note `mysqld_safe': mysqld-safe. `safe_mysqld' has been deprecated since MySQL 4.0 and now is removed. * Special characters in database and table identifiers now are encoded when creating the corresponding directory names and file names. This relaxes the restrictions on the characters that can appear in identifiers. See *Note identifier-mapping::. * Added the `event_scheduler' system variable. * MySQL 5.1.6 introduces the _Event Scheduler_ which enables statements to be scheduled for execution at predetermined times. Events can be transient (one-time-only) or recurrent at regular intervals, and may execute queries and statements permitted in stored routines, including compound statements. Events can be altered after creation, and dropped when no longer needed. Information about scheduled events can be obtained using the statements *Note `SHOW EVENTS': show-events. and *Note `SHOW CREATE EVENT': show-create-event, or by querying the *Note `INFORMATION_SCHEMA.EVENTS': events-table. table. All of these are available beginning in MySQL 5.1.6. Users must have the `EVENT' privilege (also added in 5.1.6) to create events. For more information, see *Note events::. * Distributions include both a *Note `mysqld': mysqld. optimized server and *Note `mysqld-debug': mysqld. debugging server. There is no separate debug distribution. * Server binaries no longer are stripped, except for RPM distributions. * The `ARCHIVE' storage engine now supports the `AUTO_INCREMENT' column attribute and the `AUTO_INCREMENT' table option. *Note archive-storage-engine::. * Server plugins can register their own status variables to be displayed by the *Note `SHOW STATUS': show-status. statement. * Added the *Note `PARTITIONS': partitions-table. table to `INFORMATION_SCHEMA'. * Added the *Note `EVENTS': events-table. table to `INFORMATION_SCHEMA'. *Bugs fixed:* * *MySQL Cluster*: *Note `NDB': mysql-cluster. leaked disk space when performing repeated *Note `INSERT': insert. or *Note `DELETE': delete. statements. (Bug #16771) * *MySQL Cluster*: *Note `ndb_delete_all': mysql-cluster-programs-ndb-delete-all. ran out of memory when processing tables containing *Note `BLOB': blob. columns. (Bug #16693) * *MySQL Cluster*: Trying to import too many dumped tables requiring resources beyond those allocated in the cluster configuration file caused the server to crash instead of reporting an insufficient resources error. (Bug #16455) * *MySQL Cluster*: A *Note `BIT': numeric-types. column whose offset and length totaled 32 caused the cluster to crash. (Bug #16125) * *MySQL Cluster*: The `ndb_autodiscover' test failed sporadically due to a node not being permitted to connect to the cluster. (Bug #15619) * *MySQL Cluster*: *Note `NDB': mysql-cluster. returned an incorrect `Can't find file error' for OS error 24; this has been changed to `Too many open files'. (Bug #15020) * *MySQL Cluster*: *Note `CREATE TABLESPACE': create-tablespace. statements were incorrectly parsed on 64-bit platforms. (`INITIAL SIZE SIZE' worked, but `INITIAL SIZE = SIZE ' failed.) (Bug #13556) * *MySQL Cluster*: Using *Note `mysqldump': mysqldump. to obtain a dump of a partitioned table employing the *Note `NDB': mysql-cluster. storage engine produced a nonfunctional table creation statement. (Bug #13155) * *Disk Data*: Tablespaces created using parameters with relatively low values (10 MB or less) produced filesizes much smaller than expected. (Bug #16742) * *Disk Data*: *Note `NDB': mysql-cluster. returned the wrong error when the tablespace on disk was full. (Bug #16738) * *Disk Data*: The error message generated by a failed `ADD UNDOFILE' did not provide any reasons for the failure. (Bug #16267) * *Disk Data*: *Note `DROP LOGFILE GROUP': drop-logfile-group. corrupted the cluster file system and caused *Note `ndbd': mysql-cluster-programs-ndbd. to fail when running more than one node on the same system. (Bug #16193) * *Cluster API*: Upon the completion of a scan where a key request remained outstanding on the primary replica and a starting node died, the scan did not terminate. This caused incomplete error handling for the failed node. (Bug #15908) * When the full-text search parser plugin returned more words than half of the length (in bytes) of the query string, the server would crash. (Bug #16722) * An indexing error sometimes caused values to be assigned to the wrong `RANGE' partition. (Bug #16684) * An *Note `INSERT': insert. statement in a stored procedure corrupted the binary log. (Bug #16621) * Trying to add more than one partition in a single `ALTER TABLE ... ADD PARTITION' statement caused the server to crash. (Bug #16534) * Parallel builds occasionally failed on Solaris. (Bug #16282) * Inserting a negative value into an integer column used as the partitioning key for a table partitioned by `HASH' could cause the server to crash. (Bug #15968) * Creating a partitioned table using a storage engine other than the session default storage engine caused the server to crash. (Bug #15966) * The error message for specifying values for which no partition exists returned wrong values on certain platforms. (Bug #15910) * Specifying a value for `--tmpdir' without a trailing slash had unpredictable results. (Bug #15904) * `STR_TO_DATE(1,NULL)' caused a server crash. (Bug #15828, CVE-2006-3081) * `ALTER TABLE ... ADD PARTITIONS' on a table with one partition crashed the server. (Bug #15820) * The *Note `mysql_real_connect()': mysql-real-connect. C API function incorrectly reset the `MYSQL_OPT_RECONNECT' option to its default value. (Bug #15719) * In some cases the query optimizer did not properly perform multiple joins where inner joins followed left joins, resulting in corrupted result sets. (Bug #15633) * Certain permission management statements could create a `NULL' host name for a user, resulting in a server crash. (Bug #15598) * Improper memory handling for stored routine variables could cause memory overruns and binary log corruption. (Bug #15588) * The absence of a table in the left part of a left or right join was not checked prior to name resolution, which resulted in a server crash. (Bug #15538) * An `ALTER TABLE ... PARTITION BY ...' statement did not have any effect. (Bug #15523) * Using `RANGE' partitioning with a `CASE' expression as the partitioning function would cause records to be placed in the wrong partition. (Bug #15393) * Certain subqueries where the inner query was the result of a aggregate function would return different results with MySQL 5.1 than with MySQL 4.1. Subselects could also return wrong results when the query cache and grouping were involved. (Bug #15347) * Attempting to insert data into a partitioned table that used the `BLACKHOLE' storage engine caused *Note `mysqld': mysqld. to crash. (Bug #14524) * A `FULLTEXT' query in a prepared statement could result in unexpected behavior. (Bug #14496) * With a table partitioned by `LIST', inserting a value which was smaller than any value shown in the partitioning value-lists could cause the server to crash. (Bug #14365) * The `DATA DIRECTORY' and `INDEX DIRECTORY' clauses of a *Note `CREATE TABLE': create-table. statement involving partitions did not work. (Bug #14354) * *Note `SHOW CREATE TABLE': show-create-table. did not display the `PARTITIONS' clause for tables partitioned by `HASH' or `KEY'. (Bug #14327) * `ALTER TABLE ... DROP PARTITION' would truncate all *Note `DATE': datetime. column values in the table's remaining partitions to `NULL'. (Bug #13644) * `ALTER TABLE ... ADD PARTITION' could crash the server or cause an `Out of memory' error in some circumstances. (Bug #13447) * The server would permit foreign keys to be declared in the definition of a partitioned table despite the fact that partitioned tables do not support foreign keys (see *Note partitioning-limitations::). (Bug #13446) * A *Note `SELECT': select. from a key-partitioned table with a multi-column key could cause the server to crash. (Bug #13445) * Issuing a *Note `TRUNCATE TABLE': truncate-table. statement twice in succession on the same partitioned table would cause the server to crash. (Bug #13442) * Using a *Note `REPLACE': replace. statement on a partitioned table caused the server to crash. (Bug #13440) * Using an identifier rather than a literal integer value in the `LESS THAN' clause of a range-partitioned table could cause the server to crash and corruption of tables. (Bug #13439) * Using `ENGINE=...' within a `PARTITION' clause could cause the server to crash. (Bug #13438) * *Note `CREATE TABLE ... LIKE': create-table. did not work if the table whose schema was to be copied was a partitoned table. (Bug #13435) * Multi-byte path names for *Note `LOAD DATA': load-data. and *Note `SELECT ... INTO OUTFILE': select. caused errors. Added the `character_set_filesystem' system variable, which controls the interpretation of string literals that refer to file names. (Bug #12448) * Temporary table aliasing did not work inside stored functions. (Bug #12198) * Using the `TRUNCATE()' function with a negative number for the second argument on a *Note `BIGINT': numeric-types. column returned incorrect results. (Bug #8461) * Certain Japanese table names were not properly saved during a *Note `CREATE TABLE': create-table. statement. (Bug #3906)  File: manual.info, Node: news-5-1-5, Next: news-5-1-4, Prev: news-5-1-6, Up: news-5-1-x D.1.63 Changes in MySQL 5.1.5 (10 January 2006) ----------------------------------------------- *Functionality added or changed:* * *Replication*: Added the `binlog_format' system variable that controls whether to use row-based or statement-based binary logging. Added the `--binlog-format' and `--binlog-row-event-max-size' server options for binary logging control. See *Note replication-formats::. * Added the `--port-open-timeout' option to *Note `mysqld': mysqld. to control how many seconds the server should wait for the TCP/IP port to become free if it cannot be opened. (Bug #15591) * A new statement, *Note `BINLOG': binlog, is generated by *Note `mysqlbinlog': mysqlbinlog. to represent row-based events in binary log files. The statement argument, a base 64-encoded string, is decoded by the server to determine the data change indicated by the corresponding event. * Added the `--create-schema', `--lock-directory', `--number-of-queries', `--only-print', `--preserve-schema', and `--slave' options for *Note `mysqlslap': mysqlslap. * If `innodb_locks_unsafe_for_binlog' is enabled or if the transaction isolation mode is `READ COMMITTED', *Note `InnoDB': innodb-storage-engine. can use `semi-consistent' reads. This affects treatment by *Note `UPDATE': update. statements for rows that are already locked by another transaction. If a row is locked, *Note `InnoDB': innodb-storage-engine. returns the latest committed version to MySQL so that MySQL can determine whether the row matches the `WHERE' condition of the *Note `UPDATE': update. If the row matches (must be updated), MySQL reads the row again and this time *Note `InnoDB': innodb-storage-engine. either locks it or waits for a lock on it. See also Bug #3300. * Added the `--base64-output' option to *Note `mysqlbinlog': mysqlbinlog. to print all binary log entries using base64 encoding. This is for debugging only. Logs produced using this option should not be applied on production systems. * Added the `INFORMATION_SCHEMA PLUGINS' table and the `SHOW PLUGIN' statement. * Two new Hungarian collations are included: `utf8_hungarian_ci' and `ucs2_hungarian_ci'. These support the correct sort order for Hungarian vowels. However, they do not support the correct order for sorting Hungarian consonant contractions; we expect to fix this issue in a future release. * Plugins now can have status variables that are displayed in the output from *Note `SHOW STATUS': show-status. See *Note writing-plugins::. * Added the `INFORMATION_SCHEMA ENGINES' table. * Added the XML functions `ExtractValue()' and `UpdateXML()'. `ExtractValue()' returns the content of a fragment of XML matching a given XPath expression. `UpdateXML()' replaces the element selected from a fragment of XML by an XPath expression supplied by the user with a second XML fragment (also user-supplied), and returns the modified XML. See *Note xml-functions::. *Bugs fixed:* * *Note `INSERT DELAYED': insert-delayed. caused *Note `mysqld': mysqld. to crash. (Bug #16095) * The `--plugin_dir' option was not working. Specifying the parser name for full-text also did not work correctly. (Bug #16068) * Attempting to insert into a table partitioned by `LIST' a value less than any specified in one of the table's partition definitions resulted in a server crash. In such cases, *Note `mysqld': mysqld. now returns `ERROR 1500 (HY000): Table has no partition for value V ' , where V is the out-of-range value. (Bug #15819) * Issuing a *Note `DROP USER': drop-user. statement could cause some users to encounter a ` HOSTNAME is not permitted to connect to this MySQL server' error. (Bug #15775) * The output of *Note `mysqldump --triggers': mysqldump. did not contain the `DEFINER' clause in dumped trigger definitions. (Bug #15110) * The output of *Note `SHOW TRIGGERS': show-triggers. contained extraneous whitespace. (Bug #15103) * Creating a trigger caused a server crash if the table or trigger database was not known because no default database had been selected. (Bug #14863) * `InnoDB': Comparison of indexed `VARCHAR CHARACTER SET ucs2 COLLATE ucs2_bin' columns using `LIKE' could fail. (Bug #14583) * A *Note `COMMIT': commit. statement followed by a *Note `ALTER TABLE': alter-table. statement on a BDB table caused server crash. (Bug #14212) * An *Note `INSERT ... SELECT': insert-select. statement between tables in a `MERGE' set can return errors when statement involves insert into child table from merge table or vice-versa. (Bug #5390) * `InnoDB': A semi-consistent read for an *Note `UPDATE': update. statement with no index column in the `WHERE' condition locked all the rows in the table. (Bug #3300)  File: manual.info, Node: news-5-1-4, Next: news-5-1-3, Prev: news-5-1-5, Up: news-5-1-x D.1.64 Changes in MySQL 5.1.4 (21 December 2005) ------------------------------------------------ *Functionality added or changed:* * Added the `--server-id' option to *Note `mysqlbinlog': mysqlbinlog. to enable only those events created by the server having the given server ID to be extracted. (Bug #15485) * It is now possible to build the server such that `MyISAM' tables can support up to 128 keys rather than the standard 64. This can be done by configuring the build using the option `--with-max-indexes=N ', where N<=128 is the maximum number of indexes to permit per table. (Bug #10932) * Added the `myisam_use_mmap' system variable. * Added the `--bdb-data-direct' and `--bdb-log-direct' server options. * Added the *Note `mysqlslap': mysqlslap. program, which is designed to emulate client load for a MySQL server and report the timing of each stage. It works as if multiple clients are accessing the server. * The bundled `BDB' library was upgraded to version 4.4.16. * Added the `cp1250_polish_ci' collation for the `cp1250' character set. *Bugs fixed:* * *MySQL Cluster*: The `--ndb' option for *Note `perror': perror. did not function. (Bug #15486) * *MySQL Cluster*: Using `ORDER BY PRIMARY_KEY_COLUMN' when selecting from a table having the primary key on a *Note `VARCHAR': char. column caused a forced shutdown of the cluster. (Bug #15240, Bug #15682, Bug #14828, Bug #15517) * Server could not be built on default Debian systems with BDB enabled. (Bug #15734) * *Note `SHOW ENGINES': show-engines. output showed the `FEDERATED' engine as `DISABLED' even for builds with `FEDERATED' support. (Bug #15559) * `BDB': A *Note `DELETE': delete, *Note `INSERT': insert, or *Note `UPDATE': update. of a `BDB' table could cause the server to crash where the query contained a subquery using an index read. (Bug #15536) * It was not possible to reorganize a partition reusing a discarded partition name. Now, for example, you can create a table such as this one: CREATE TABLE t1 (a INT) PARTITION BY RANGE (a) ( PARTITION p0 VALUES LESS THAN (10), PARTITION p1 VALUES LESS THAN (20), PARTITION p2 VALUES LESS THAN MAXVALUE ); and then repartition it as shown here: ALTER TABLE t1 REORGANIZE PARTITION p2 INTO ( PARTITION p2 VALUES LESS THAN (30) ); Previously, attempting to do so would produce the error `All partitions must have unique names in the table' . (Bug #15521) * The `BLACKHOLE' storage engine did not handle transactions properly: Rolled-back transactions were written to the binary log. Now they ae not. (Bug #15406) * A left join on a column that having a `NULL' value could cause the server to crash. (Bug #15268) * Selecting from a view processed with the temptable algorithm caused a server crash if the query cache was enabled. (Bug #15119) * Creating a view that referenced a stored function that selected from a view caused a crash upon selection from the view. (Bug #15096) * Multiple-table update operations were counting updates and not updated rows. As a result, if a row had several updates it was counted several times for the `rows matched' value but updated only once. (Bug #15028) * `ROW_COUNT()' returned an incorrect result after *Note `EXECUTE': execute. of a prepared statement. (Bug #14956) * *Note `ANALYZE TABLE': analyze-table. did not properly update table statistics for a `MyISAM' table with a `FULLTEXT' index containing stopwords, so a subsequent *Note `ANALYZE TABLE': analyze-table. would not recognize the table as having already been analyzed. (Bug #14902) * Creating a view within a stored procedure could result in an out of memory error or a server crash. (Bug #14885) * *Note `SELECT': select. queries that began with an opening parenthesis were not being placed in the query cache. (Bug #14652) * Space truncation was being ignored when inserting into *Note `BINARY': binary-varbinary. or *Note `VARBINARY': binary-varbinary. columns. Now space truncation results in a warning, or an error in strict mode. (Bug #14299) * The maximum value of `MAX_ROWS' was handled incorrectly on 64-bit systems. (Bug #14155) * For binary string data types, *Note `mysqldump --hex-blob': mysqldump. produced an illegal output value of `0x' rather than `'''. (Bug #13318) * Some comparisons for the `IN()' operator were inconsistent with equivalent comparisons for the `=' operator. (Bug #12612) * Attempts to assign `NULL' to a `NOT NULL' column in strict mode now result in a message of `Column 'COL_NAME' cannot be null', rather than `Column set to default value; NULL supplied to NOT NULL column 'COL_NAME' at row N'. (Bug #11491) * *Note `SHOW CREATE DATABASE': show-create-database. was sometimes refused when the client had privileges for the database. (Bug #9785) * Invalid casts to *Note `DATE': datetime. values now result in a message of `Incorrect datetime value', rather than `Truncated incorrect datetime value'. (Bug #8294) * *Note `mysql': mysql. ignored the `MYSQL_TCP_PORT' environment variable. (Bug #5792)  File: manual.info, Node: news-5-1-3, Next: news-5-1-2, Prev: news-5-1-4, Up: news-5-1-x D.1.65 Changes in MySQL 5.1.3 (29 November 2005) ------------------------------------------------ *Functionality added or changed:* * *Plugin API*: *Incompatible Change*: MySQL 5.1 adds support for a very flexible plugin API that enables loading and unloading of various components at runtime, without restarting the server. Although the work on this is not finished yet, _plugin full-text parsers_ are a first step in this direction. This enables users to implement their own input filter on the indexed text, enabling full-text search capability on arbitrary data such as PDF files or other document formats. A pre-parser full-text plugin performs the actual parsing and extraction of the text and hands it over to the built-in MySQL full-text search. (Author: Sergey Vojtovich) The plugin API requires the `mysql.plugin' table. When upgrading from an older version of MySQL, you should run the *Note `mysql_fix_privilege_tables': mysql-fix-privilege-tables. command to create this table. See *Note mysql-fix-privilege-tables::. Plugins are installed in the directory named by the `plugin_dir' system variable. This variable also controls the location from which the server loads user-defined functions (UDFs), which is a change from earlier versions of MySQL. That is, all UDF library files now must be installed in the plugin directory. When upgrading from an older version of MySQL, you must migrate your UDF files to the plugin directory. * *Incompatible Change*: Renamed the `table_cache' system variable to `table_open_cache'. Any scripts that refer to `table_cache' should be updated to use the new name. * *MySQL Cluster*: *Note `VARCHAR': char. columns used in MySQL Cluster tables are now variable-sized; that is, they now only allocate as much space as required to store the data. Previously, a `VARCHAR(N)' column allocated n+2 bytes (aligned to 4 bytes), regardless of whether the actual inserted value required that much space. (In other words, a *Note `VARCHAR': char. column always required the same, fixed, amount of storage as a *Note `CHAR': char. column of the same size.) * *Partitioning*: MySQL Server now supports user-defined table partitioning, which enables distributing portions of individual tables across a file system, according to rules which can be set when the table is created. In effect, different portions of a table are stored as separate tables in different locations, but from the user point of view, the partitioned table is still a single table. See *Note partitioning::, for further information on this functionality. (Author: Mikael Ronstro"m) * `RAND()' no longer permits nonconstant initializers. (Previously, the effect of nonconstant initializers is undefined.) (Bug #6172) * Added the `table_definition_cache' system variable. If you use a large number of tables, you can create a large table definition cache to speed up opening of tables. The table definition cache takes less space and does not use file descriptors, unlike the normal table cache. * `SET INSTANCE_NAME. OPTION_NAME=OPTION_VALUE ' sets an option to the specified value and writes it to the config file See *Note instance-manager::, for more details on these new commands. (Author: Petr Chardin) * `SHOW INSTANCE_NAME LOG FILES' provides a listing of all log files used by the instance. (Author: Petr Chardin) * Added the *Note `SHOW AUTHORS': show-authors. statement. * Fast *Note `ALTER TABLE': alter-table.: Operations that change only table metadata and not table data do not require a temporary table to be used, which improves performance. For example, renaming a column changes only the `.frm' file and no longer uses a temporary table. * *The Instance Manager (IM)* now has some additional functionality: * `SHOW INSTANCE_NAME LOG FILES' provides a listing of all log files used by the instance. (Author: Petr Chardin) * `SHOW INSTANCE_NAME LOG {ERROR | SLOW | GENERAL} SIZE ' retrieves a part of the specified log file. (Author: Petr Chardin) * `SET INSTANCE_NAME. OPTION_NAME=OPTION_VALUE ' sets an option to the specified value and writes it to the config file See *Note instance-manager::, for more details on these new commands. (Author: Petr Chardin) * `SHOW INSTANCE_NAME LOG {ERROR | SLOW | GENERAL} SIZE ' retrieves a part of the specified log file. (Author: Petr Chardin) * Added the *Note `SHOW FUNCTION CODE': show-function-code. and *Note `SHOW PROCEDURE CODE': show-procedure-code. statements (available only for servers that have been built with debugging support). See *Note show-procedure-code::. * The performance of boolean full-text searches (using the `+' Operator) has been improved. See *Note fulltext-search::, for more details about full-text searching. (Author: Sergey Vojtovich) *Bugs fixed:* * *Note `RESET MASTER': reset-master. failed to delete log files on Windows. One consequence of this change is that server opens the general query and slow log files in shared mode, so now they can be renamed while the server has them open (something not true in previous versions). (Bug #13377) * Set functions could not be aggregated in outer subqueries. (Bug #12762)  File: manual.info, Node: news-5-1-2, Next: news-5-1-1, Prev: news-5-1-3, Up: news-5-1-x D.1.66 Changes in MySQL 5.1.2 (Not released) -------------------------------------------- *Functionality added or changed:* * Added the `bdb_cache_parts' and `bdb_region_size' system variables, and permitted `bdb_cache_size' to be larger than 4GB on systems that support it. (Bug #14895) * Added `MAXLOCKS', `MINLOCKS', `MAXWRITE', and `MINWRITE' as permissible values of the `--bdb-lock-detect' option. (Bug #14876) * Added `--replace' to *Note `mysqldump': mysqldump. This option uses `REPLACE INTO', rather than `INSERT INTO', when writing the dumpfile. * Added `Transactions', `XA', and `Savepoints' columns to *Note `SHOW ENGINES': show-engines. output. *Bugs fixed:* * Foreign keys were not properly enforced in `TEMPORARY' tables. Foreign keys are no longer permitted in `TEMPORARY' tables. (Bug #12084)  File: manual.info, Node: news-5-1-1, Prev: news-5-1-2, Up: news-5-1-x D.1.67 Changes in MySQL 5.1.1 (Not released) -------------------------------------------- *Bugs fixed:* * *Partitioning*: *MySQL Cluster*: Specifying the wrong nodegroup in a *Note `CREATE TABLE': create-table. statement using partitioning would lead to the table name being locked after the statement failed (that is, the table name could not be re-used). (Bug #12114) * Using `ORDER BY' in a query with a partitioned table on a 64-bit operating system could crash the server. (Bug #12116) * Performing a *Note `CREATE TABLE': create-table. statement with a `PARTITION BY' clause in a prepared statement could crash a server running in debug mode. (Bug #12097) * When two threads competed for the same table, a deadlock could occur if one thread also had a lock on another table through *Note `LOCK TABLES': lock-tables. and the thread was attempting to remove the table in some manner while the other thread tried to place locks on both tables. (Bug #10600)  File: manual.info, Node: mem-news, Next: connector-odbc-news, Prev: news-5-1-x, Up: news D.2 MySQL Enterprise Monitor Change History =========================================== * Menu: * mem-news-2-1-2:: Changes in MySQL Enterprise Monitor 2.1.2 (26 May 2010) * mem-news-2-1-1:: Changes in MySQL Enterprise Monitor 2.1.1 (10 February 2010) * mem-news-2-1-0:: Changes in MySQL Enterprise Monitor 2.1.0 (08 September 2009) This appendix lists the changes to the MySQL Enterprise Monitor, beginning with the most recent release. Each release section covers added or changed functionality, bug fixes, and known issues, if applicable. All bug fixes are referenced by bug number and include a link to the bug database. Bugs are listed in order of resolution. To find a bug quickly, search by bug number.  File: manual.info, Node: mem-news-2-1-2, Next: mem-news-2-1-1, Prev: mem-news, Up: mem-news D.2.1 Changes in MySQL Enterprise Monitor 2.1.2 (26 May 2010) ------------------------------------------------------------- This section documents all changes and bug fixes that have been applied since the release of MySQL Enterprise Monitor, version 2.1.1. *Bugs fixed:* * *Security Fix*: A number of cross-site request forging issues have been identified and resolved. (Bug #52888, Bug #52910, Bug #52905, Bug #52897) * On Windows platforms, the MySQL Enterprise Monitor Agent could show increasing memory usage over time. (Bug #54313) * MySQL Enterprise Service Manager would crash during initial startup on Solaris SPARC 64-bit. (Bug #53751) * The dialog box during installation of MySQL Enterprise Service Manager has been updated to make the process of installing MySQL Enterprise Service Manager when using an existing MySQL server. (Bug #52839) * Using `LOAD DATA LOCAL INFILE' would cause the proxy component of MySQL Enterprise Monitor Agent to terminate. (Bug #51864) * Scheduling a rule against an instance, and then deleting that instance, would retain the instance within MySQL Enterprise Dashboard, identified as `Unknown'. (Bug #51095) * Deleting a server within MySQL Enterprise Dashboard could cause a `foreign key constraint' error. (Bug #50927) * Deleting a server that had purged all its monitoring data, but still have query analyzer information, would fail. (Bug #50916) * When using the MySQL Enterprise Agent Proxy Service, if the backend MySQL server went down, and then the clock on the MySQL Enterprise Agent Proxy Service host went back in time (for example, during daylight savings time adjustments), the MySQL Enterprise Agent Proxy Service would stop sending queries to the configured backend. (Bug #50806) * The SSL certificates supplied with MySQL Enterprise Service Manager have been updated. The certificate shipped with MySQL Enterprise Service Manager is an example certificate that expires after 1 year and that folks should create their own and back it up between MEM service manager updates. For more information on updating the certificate, see Creating a new SSL KeyStore (http://dev.mysql.com/doc/mysql-monitor/2.1/en/mem-reference.html#mem-program-reference-server-ssl). (Bug #50694) * Clicking a link to a support issue within the dashboard is now configured to open the issue within a new window. (Bug #50651) * The MySQL Enterprise Monitor Agent could report data using an old timestamp, or report information for a server that the MySQL Enterprise Monitor Agent can no longer connect to due to a permissions change. (Bug #50449) * Monitoring of a server that had `INFORMATION_SCHEMA', and a large number of schemas or tables could upset the gathering of monitoring data. (Bug #47947) * MySQL Enterprise Monitor Agent would fail to monitor MySQL servers using the InfoBright storage engine. (Bug #47165) * If you specify an invalid backend proxy address to MySQL Enterprise Monitor Agent, the agent would fail silently. (Bug #46927) * Installation on certain platforms could fail during the generation of a UUID because of a lack of privileges. A separate UUID generation tool, `agent-generate-uuid' is now used to create the UUID. (Bug #46370) * If a customer was using their own SSL certificate, they entered that information in the `server.xml' file. However, running the upgrade installer caused `server.xml', and any custom certificates, to be replaced. (Bug #44525) * Starting the agent could lead to an error regarding the `ssh-keygen' tool and a missing library (`libcrypto'). (Bug #43125)  File: manual.info, Node: mem-news-2-1-1, Next: mem-news-2-1-0, Prev: mem-news-2-1-2, Up: mem-news D.2.2 Changes in MySQL Enterprise Monitor 2.1.1 (10 February 2010) ------------------------------------------------------------------ This section documents all changes and bug fixes that have been applied since the release of MySQL Enterprise Monitor, version 2.1.0. *Functionality added or changed:* * The smallest purge log time interval that could be set in the Dashboard was one week. MySQL Enterprise Monitor was changed to enable setting the smallest purge log time interval to one day. (Bug #46822) * Certain heat chart rules cannot be unscheduled or disabled, this is because they are required for correct operation of MySQL Enterprise Monitor. Should an attempt be made to unschedule or disable one of these heat chart rules, a suitable message is now displayed, explaining this requirement. (Bug #46535) * If you are monitoring one instance of MySQL server *Note `mysqld': mysqld. and then upgrade that MySQL server, the correct version of the MySQL server is not displayed in the Dashboard. The agent will now perform a re-synchronization of the inventory if it identifies that the server has gone away and that the monitored MySQL has been upgraded. (Bug #38409) *Bugs fixed:* * The MySQL Enterprise Monitor Agent could fail to reconnect to a monitored MySQL instance if the agent was started while the MySQL instance was unavailable. (Bug #50797) * When installing MySQL Enterprise Monitor Agent on a Linux operating system using the SELinux security environment, the installation would fail if the `allow_execstack' option had been enabled. (Bug #50515) * When purging old data, the purging process could fail to remove all of the data if the inflow of new information was very high. Purging now removes all outdated information at each execution. (Bug #50422) * It was possible to updated an existing email notification list with two email addresses in the destination without a required comma between the addresses. Addresses are now validated during the editing phase to ensure that this does not occur. (Bug #50161) * The agent could not be installed on Mac OS X Snow Leopard (10.6) due to an incompatibility in the XML libraries used. (Bug #50126) * Deleting users within MySQL Enterprise Service Manager could lead to errors in the repository database that would affect further operations involving the deleted user. (Bug #49896) * When creating a new instance by copying an existing agent configuration, it is possible to create an orphaned agent. The recommended advice is to `TRUNCATE' the `mysql.inventory' table. However, doing this could lead to additional errors and an exception when the scheduled data updates on the now orphaned agent are executed. (Bug #49882) * Monitoring a MySQL 4.0 server would fail because MySQL 4.0 did not support table-level character set support. (Bug #49082) * RAM statistics for FreeBSD machines would not be reported correctly by MySQL Enterprise Monitor Agent. (Bug #48493) * The agent installer for Solaris on x64 would fail due to a library linker issue during the postinstallation phase of the installer. (Bug #48336) * The URL for viewing the contents of an event alerted by email were not populated correctly, making the supplied URL invalid. (Bug #48193) * Support has been added for SNMPv2 traps in addition to the existing SNMPv1 traps. You can configure the version to use for SNMP traps, see `SNMP Traps' (http://dev.mysql.com/doc/mysql-monitor/2.1/en/mem-global-settings.html#mem-snmp-traps). In addition, support has also been added to send SNMP notifications to two hosts in place of just one host. Notifications are sent to both hosts simultaneously. (Bug #47686, Bug #48955) * Support issues can have a Severity from S1 through S4, but can also have a value of `NS' meaning `No Severity Set'. MySQL Enterprise Monitor was not able to parse this, which resulted in errors such as the following: 2009-09-23 13:53:51,812 ERROR [em-worker-pool-thread-6:monitor.support.DevSpPoller] error consuming successful response java.lang.IllegalArgumentException: No enum const class com.mysql.etools.monitor.support.SpIssue$Severity.NS at java.lang.Enum.valueOf(Enum.java:196) ... (Bug #47562) * The pagination of errors within MySQL Enterprise Dashboard for MySQL Enterprise Service Manager logging made it difficult to identify the true source of the error. (Bug #47464) * An additional link has been added to the `Configure What's New' page to link to the relevant documentation. (Bug #47256) * MySQL Enterprise Monitor would fail to install on Miracle Linux4. (Bug #47209) * Some strings in the `What's New' tab of MySQL Enterprise Dashboard had not been translated from English to Japanese. (Bug #47203) * The diagnostic report file has been updated so that the filename of the report includes the timestamp when the report was generated. (Bug #47164) * When the `Configuring and troubleshooting this feed' link was clicked it opened the help screen in the current browser window, rather than in a new window. The link can be found on the `What's New' tab, at the bottom of the `Important Product-Related Announcements' section, in the `Welcome to the "What's New?" Live Feed!' sub-section. (Bug #47145) * The links for further information on the `What's New' feed were invalid. (Bug #47133) * When the Help link was clicked in the Dashboard, the following script error was generated: row: 32 char: 5 error: object expected code: 0 URL: http://xxx.yyy.com:38080/Help.action This only happened when using Internet Explorer. (Bug #47065) * The times used for queries in Query Analyzer would not match the time set for the user's timezone and browser setting. (Bug #47040) * The date format in the `configure what's new' pop-up on the `What's New?' tab did not reflect the locale set in the `User Preferences' page. (Bug #46901) * Two links in the Agent installer were incorrect. The link https://enterprise.mysql.com/docs/monitor/2.0/en/mem-install.html#mem-agent-rights should have pointed to https://enterprise.mysql.com/docs/monitor/2.1/en/mem-install.html#mem-agent-rights. Also, the link https://enterprise.mysql.com/docs/monitor/2.1/en/mem-query-analysis.html should have pointed to https://enterprise.mysql.com/docs/monitor/2.1/en/mem-query-analyzer.html. (Bug #46812) * The `REPLACE' and `CALL' statements did not show a rows graph within the statement pop-up graph tab. (Bug #46796) * When updating your scription after the subscription has expired, the ability to update your advisor bundle was not available. (Bug #46700) * The task message for a given server within the agent would be logged at the incorrect level. Messages are now logged at the message level. (Bug #46681) * Pressing cancel on a pop-up would cause a page reload, instead of just closing the pop-up window. (Bug #46604) * The cry for help email included a stack trace, however it was displayed on a single line without any line breaks. (Bug #46458) * If the `Last' link was clicked on the Infrastructure logs page, the following error was generated: Error Message fromIndex(400) > toIndex(31) (Bug #46229) * When using MySQL Enterprise Monitor Agent, if the current configured time went backward (for example, during time correction), the MySQL Enterprise Monitor Agent would stop reporting data and induce a high load on the machine running MySQL Enterprise Monitor Agent (Bug #46052) * The Windows installers for MySQL Enterprise Service Manager did not include 64-bit versions of the various binary tools. (Bug #45682) * The agent could get into a state where it loop through the resynchronization of the core data, without reporting information to the service manager, causing gaps in the data. (Bug #45382) * The IP address of the agent host on FreeBSD 7 systems would not be reported correctly. (Bug #45079)  File: manual.info, Node: mem-news-2-1-0, Prev: mem-news-2-1-1, Up: mem-news D.2.3 Changes in MySQL Enterprise Monitor 2.1.0 (08 September 2009) ------------------------------------------------------------------- This section documents all changes and bug fixes that have been applied since the release of MySQL Enterprise Monitor, version 2.0.6. *Functionality added or changed:* * *Incompatible Change*: The default proxy port used to relay queries when using the Query Analyzer has been changed from port 4040 to 6446. * The Agent did not write its version number to the log on startup or shutdown. The information is now available by setting log level `MESSAGE' in the Dashboard. It is also available when running the Agent from the command line with the command `mysql-monitor-agent `--version''. The Agent also now logs its version number on startup if the log level is set to `CRITICAL'. (Bug #45884) * The Agent did not have a configurable response size. The response size was hard coded to 65K. However, with large inventories, the customer might need to use a larger response size. The Agent command line option `--agent-max-response-size' was added which will set the maximum size (in bytes) of the response the agent will send to the Service Manager. The default is 65536. (Bug #45571) * If the Service Manager lost connection to the repository server, it would shut down after 50 attempts to reconnect or if it was unable to reconnect within 180 seconds. This behavior has now been made configurable through parameters in the `config.properties' file. The parameters are: * `mysql.max_connect_retries' - default is 50. * `mysql.max_connect_timeout_msec' - default is 180 seconds. (Bug #45471) * There was no way to force the Agent to resynch with the Service Manager. A link has now been added. The link can be found on the `Settings', `Manage Servers' page - click the context menu next to a server, the menu now contains a `Refresh' item. (Bug #45461) * When the Agent debug log was examined, it was found to contain XML returned by the Service Manager that did not contain carriage returns. This made the data difficult to read by a human. The Service Manager has been changed to return formatted XML. (Bug #45460) * The version of Enterprise Monitor was not logged on startup. Enterprise Monitor was changed to log the Monitor and Advisor version number on startup. See also Bug#45884. (Bug #45459) * The ability to customize the text of the email sent for an event was added. The URL to the event can now be added to the email, so that the administrator does not have to search for the action that triggered the email. (Bug #44383) * In large installations it can be desirable to locate the repository MySQL Server and the Tomcat server on difference computers to reduce load. However, the script `mysqlmonitorctl.sh' assumed these were running on the same server. The script was therefore changed to accommodate the above requirement. The `mysqlmonitorctl.sh' script now checks for a new configuration file called `mysqlmonitorctl.conf'. This configuration file is located in a new directory, `etc/defaults', relative to the install directory. The configuration file contains 2 variables: * START_MYSQL=yes * START_TOMCAT=yes The script will then start/stop the MySQL Server and Tomcat accordingly. Defaults for both variables in the file are set to `yes'. The update installers will not overwrite this file. (Bug #44379) * When Replication was configured to use SSL for encrypting the transfer of the binary log, even though replication worked and the dashboard displayed the replication group correctly, the agent still logged the following message (repeatedly): 2009-04-06 16:12:00: (critical) job_collect_mysql.c:698: [mysql] (master-uuid) mysql_real_connect(hostname:port replication:...) to the slave's master failed: Access denied for user 'replication'@'hostname' (using password: YES) (1045) (Bug #44200) * It was not possible to keep logs for a specific period of more than 52 weeks. The value for purging logs could be set in `Settings', `Global Settings' to values ranging from `Never' to `52 Weeks' using the drop down list boxes. The interface has now been changed to additionally offer periods of 18 months and 24 months. (Bug #43793) * Events used a GMT timestamp for the event time within email notifications, rather than the local time for the server generating the event. MySQL Enterprise Monitor has been changed so that it displays the time using the server's locale and GMT. (Bug #43739) * MySQL Enterprise Monitor did not include a graph to show `max_used_connections' versus `max_connections'. This has now been included with the Silver level advisor bundle. (Bug #43583) * A rule has been added named `Server Restarted' to signal a server restart. This has been added as a Heat Chart advisor to the Silver level advisor bundle. The rule has the following options: Expression: (%Uptime% < THRESHOLD) Critical Alert: 600 Warning Alert: 600 Info Alert: 600 Variable: %Uptime% Data Item: mysql.status:Uptime Instance: local Default frequency: 5 minutes (Bug #43243) * In the Enterprise Dashboard, it was possible to change the last remaining user with a manager role to having an agent role. This led to a problem whereby when attempting to subsequently login to the Dashboard, this caused redirection to the `setup.action' page which presents the Create Administrator facility. However, there was no `Continue' button on this page, so it was not possible to create the administrative account. The Dashboard has now been changed so that the currently logged in user is not able to change their role. (Bug #42436) * Certain alerts were misleadingly labelled as CRITICAL, and caused people to change settings unnecessarily, thereby adversely affecting their system performance and functionality. MySQL Enterprise Monitor was changed as follows: *Heat Chart Advisor* * MyISAM Key Cache Has Sub-Optimal Hit Rate. Critical threshold removed, Warning set to 75 and Info set to 85. * Query Cache Has Sub-Optimal Hit Rate. Critical threshold removed, Warning set to 40 and Info set to 50. * Temporary Tables To Disk Ratio Excessive. Critical threshold removed, others left unchanged. *Memory Usage Advisor* * InnoDB Buffer Cache Has Sub-Optimal Hit Rate. Critical threshold removed, others left unchanged. * Key Buffer Size May Not Be Optimal For Key Cache. Critical threshold removed, others left unchanged. * Key Buffer Size May Not Be Optimal For System RAM. Critical threshold removed, others left unchanged. * Table Cache Not Optimal. Critical threshold removed, Warning set to 60 and Info set to 40. * Thread Cache Size May Not Be Optimal. Critical threshold removed, Warning set to 75 and Info set to 85. *Performance Advisor* * Binary Log Usage Exceeding Disk Cache Memory Limits. Critical threshold removed, Warning set to 50 and Info set to 70. * Excessive Disk Temporary Table Usage Detected. Critical threshold removed, others left unchanged. * InnoDB Buffer Pool Writes May Be Performance Bottleneck. Critical threshold removed, Warning set to 99 and Info set to 99.5. * InnoDB Log Waits May Be Performance Bottleneck. Critical threshold removed, Warning set to 1 and Info set to 0.5. (Bug #42089) * In the Enterprise Dashboard, the `Monitor' page did not have detailed server meta information. For example, the hostname, datadir, socket and port information were not displayed. The interface has now been changed to include the following. Hostname, datadir, socket, and port information has been added to the server meta information on the monitor page. The port and datadir information has been added to the `Settings', `Manage Servers' page. Socket and datadir information has been added to the edit server pop-up. (Bug #40787) * When running multiple instances of the Enterprise Dashboard it could be difficult to determine which instance is currently being logged into. This was fixed by adding a name for the server on the login page. The name defaults to the hostname but may be changed in the `Settings' page. (Bug #40642) * The agent should be able to run as a non-`root' user. However, the startup scripts always started it as `root'. The agent chassis now has a new option `--user' to drop privileges after being started as `root'. Note, this does not work when not started as superuser, nor on Windows. A new dialog box has also been added to the agent installer. The dialog has the following text: `The agent does not need to run with `root' user privileges. The agent will switch to the user account provided below when started by the `root' user.' The dialog also has a text field to enable the entry of the user account. A new parameter was also added to the `mysql-monitor-agent.ini' file. The parameter has the format `user=xxx', where xxx is the user account to be used. (Bug #33778) * The Advisor rule `InnoDB Redo Logs Not Sized Correctly' has been renamed to `InnoDB Transaction Logs Not Sized Correctly'. The rule's Problem Description and Advice text have also been updated accordingly. (Bug #33528) * You can now configure an individual notification group to be used when sending critical email alerts. You can configure this by selecting the administration check box when configuring an individual notification group. For more information, see Manage Notification Groups (http://dev.mysql.com/doc/mysql-monitor/2.1/en/mem-dashboard-settings.html#mem-notification-groups). (Bug #30974) * The Event Log now tracks both the `Current' and `Worst' states for individual events. * To enable communication by MySQL Enterprise Service Manager with the MySQL Enterprise website, you can now configure an HTTP Proxy to be used when accessing the Internet. For more information, see Global Settings (http://dev.mysql.com/doc/mysql-monitor/2.1/en/mem-dashboard-settings.html#mem-global-settings). * The MySQL Enterprise Dashboard now includes a What's New page that incorporates information automatically from the MySQL Enterprise and MySQL Support websites. For more information, see The What's New Page (http://dev.mysql.com/doc/mysql-monitor/2.1/en/mem-whatsnew.html#mem-whatsnew). *Bugs fixed:* * The installer for MySQL Enterprise Monitor Agent on Linux 64-bit using glibc-2.3 would fail before the installation had completed properly. (Bug #50289) * The alert for `Connection Usage Excessive' recommended raising `max_connections'. However, if the users raised `max_connections' based only on the advice of the alert, they could potentially exhaust all RAM and SWAP. This alert should have made the proviso that `max_connections' be increased only if sufficient free RAM is available to support the additional connections. The alert should also have recommended checking that all connections are correctly closed, and suggest lowering the `wait_timeout' or `interactive_timeout' settings. (Bug #46921) * The `Slow Query Log Not Enabled' rule was missing a tag in the block. This caused a stack trace to be generated when the Service Manager started. (Bug #46899) * Table lock contention rules had inconsistent thresholds. The rule `lock_contention_excessive' (part of the Basic subscription) contained the following expression: (%Uptime% > 10800) && (((%Table_locks_waited% / (%Table_locks_immediate% + %Table_locks_waited%)) * 100) > THRESHOLD) This used thresholds of 1/3/5 (for Info/Warning/Critical). However, in the rule `table_lock_contention_excessive' (part of the Platinum subscription), the same expression existed but with different thresholds: (%Uptime% > 10800) && (((%Table_locks_waited% / (%Table_locks_immediate% + %Table_locks_waited%)) * 100) > THRESHOLD) In this case the thresholds were 30/60/95. (Bug #46768) * MySQL Enterprise Monitor 2.1 advisors for Windows suggested using `innodb_flush_method=unbuffered', which is an undocumented value. Only documented values should have been recommended. (Bug #46709) * When deleting a server within MySQL Enterprise Dashboard where there was a lot of historical data or a large number of instances being monitored, the deletion process could take some time and affect the loading of all pages within MySQL Enterprise Dashboard The process should no longer affect the performance UI. (Bug #46632) * The rule names and other content on the `Rules' page could be displayed without the necessary formatting and translation. (Bug #46608) * You would get a Java `NullPointerException' message if you omitted to select a server before using `Add server to group' to add a new server to an existing group. (Bug #46593) * Initial setup and registration of MySQL Enterprise Monitor could fail on Mac OS X when communicating with the MySQL Enterprise website. (Bug #46571) * The MySQL Enterprise Service Manager would send one email from each agent when agents were no longer able to write information to the repository. You now get one email containing a list of the affected agents. (Bug #46460) * The error message shown in the orange dialog when a Rule could not be scheduled showed the Rule's resource key instead of its name. For example: U0146 Unable to schedule rule "binary_logging_is_limited.name" due to "mysql.MasterStatus.Binlog_Ignore_DB" data not being collected from server "net-dev2:13306". It may be an unsupported collection for that server. (Bug #46442) * The length of the MySQL Enterprise Monitor related cookie information caused the web browser to fail with errors such as the following (from Safari 4): Bad Request Your browser sent a request that this server could not understand. Size of a request header field exceeds server limit. Cookie: __utma=183337658.3685800196369993700.1241092024.1248080652.1248188601.199; __utmc=183337658; __utmz=183337658.1247859315.194.26.ut...... (Bug #46348) * The values reported for the `os.mem.swap_page_out' and `os.mem.swap_page_in' could be identified incorrectly as delta, instead of absolute, values. (Bug #46326) * When upgrading an agent that uses SSL to connect to MySQL Enterprise Service Manager using a non-standard SSL port (i.e. not 18443), the upgrade would change the SSL port back to the default value. (Bug #46253) * When upgrading MySQL Enterprise Service Manager any custom properties set within `config.properties' would be lost. Changes are now retained during an upgrade. (Bug #46252) * When installing MySQL Enterprise Service Manager the disk space requirements could be calcualted incorrectly, which would cause the remainder of the installation to fail. (Bug #46251) * Installation of MySQL Enterprise Monitor Agent on Solaris 8 or Solaris 9 using the SPARC platform could fail if the latest patches of the SUNW UTF-8 and iconv libraries were not available. This prevented the installer from operating correctly, although the agent would work correctly. The installer for the agent has now been updated to avoid this issue. (Bug #46235) * In the Enterprise Dashboard, the query summary information pop-up on the BrowseQueries page forced a page reload after any hide. This affected both the user pressing the hide button, as well as the links on the `Example' and `Explain' tabs that caused the query summary information pop-up to be hidden, and the Query Analyzer config pop-up to be shown instead. (Bug #46230) * The Agent had a memory leak. The memory consumption increased by 35MB every five minutes. (Bug #46222) * The MySQL server embedded with MySQL Enterprise Service Manager has been updated to MySQL 5.1.37. (Bug #46214) * After a Service Manager upgrade, if there were migration errors, the message `Upgrade Status: there were errors in migration (details)' was displayed on the `Settings', `Manage Servers' page. When the details link was clicked the yellow `An Error Occurred' pop-up was briefly displayed before disappearing, making it impossible to determine the details of the error. (Bug #46181) * When installing a new Advisor JAR, the contents could overwrite localizations in your current installation. (Bug #46169) * The threshold information in email alerts listed the thresholds in a seemingly random order, for example: Thresholds Warning : 1024 Info : 512 Critical : 10240 Thresholds Info : 70 Critical : 5 Warning : 40 Thresholds Critical : 75 Warning : 85 Info : 95 (Bug #46143) * In the Enterprise Dashboard, the check boxes within the `configure what's new' panel did not function correctly. When deselecting a check box the accompanying text did not become de-emphasized (`grayed out') as expected, but only changed when another check box was selected. Further, when the check box was subsequently selected, the text did not become emphasized until another check box was selected or deselected. This problem was limited to Internet Explorer 8. (Bug #46104) * In the Enterprise Dashboard, selecting all three check boxes in the `Configure Query Analyzer' panel generated an error: The interval `00:00:00,500' could not be parsed. Intervals must be in hh:mm:ss.msec format. The error was due to the default value of `Auto-Explain Threshold' containing a `,' rather than a `.' character. (Bug #46102) * The MySQL Enterprise Monitor Agent could return a null value for a valid result set, resulting in incorrect results when using Query Analyzer. (Bug #46095) * The Rule `Non-Authorized User Has Server Admin Privileges' in the `Security' Advisor checked for the following: Create_user_priv = 'Y' File_priv = 'Y' Lock_tables_priv = 'Y' Reload_priv = 'Y' Shutdown_priv = 'Y' Super_priv = 'Y However, it did not include a check for the condition: Process_priv = 'Y' (Bug #46071) * The Query Analyzer Statement Pop-up history graphs were inconsistent with the other graphs. In particular: * The series colors were not consistent with other graphs. * The graph image was right aligned, but the title was left aligned. When the pop-up was expanded, unnecessary space was located on the left. * The Y axis did not have a Range Label. (Bug #46066) * In the Enterprise Dashboard, if a Notification Group was created, and also set to be the `MEM Admin' for cry for help emails, the MEM Admin column showed as "false" in the table overview when the group was saved. However, if the group was then edited and the flag added again, the MEM Admin status was saved. (Bug #46038) * Links in emails generated from the Query Analyzer were not linking to the Query Analyzer tab correctly. (Bug #46036) * When a query was clicked on the Query Analyzer page, the Explain Query tab displayed a potentially incorrect value for the Auto-Explain Threshold. The Threshold can actually be set to a user configurable value in Configure Query Analyzer, but the pop-up text did not reflect the currently set value, instead displaying a hard-coded default value. (Bug #46035) * The Rule `Server Includes A Root User Account' in the `Security' Advisor had a Recommended Action: UPDATE user SET user = 'new_name' WHERE user = 'root'; FLUSH PRIVILEGES; However, three other rules triggered in the case where `user' was not `root' but had administrative grants. This caused the following alerts to be generated: * Non-Authorized User Has DB, Table, Or Index Privileges On All Databases * Non-Authorized User Has GRANT Privileges On All Databases * Non-Authorized User Has Server Admin Privileges (Bug #46023) * In the Enterprise Dashboard, on the `Settings', `Manage Servers' page, the menu item `Configure Query Analyzer' generated an unhandled error message if clicked when using the Silver level subscription. Query Analyzer is not available at this subscription level, and the menu option to configure the analyzer should not be shown on this page. (Bug #46016) * If the Agent and monitored server had time settings that were out of sync the Enterprise Dashboard reported the server as `down'. (Bug #45937) * On the `What's New?' page of the Enterprise Dashboard, multiple messages were generated for the same error. This cluttered the user interface. (Bug #45927) * In the Enterprise Dashboard, when using the Safari web browser, the graph selection displayed on the `Query Analyzer' tab was sometimes drawn outside the plot area. (Bug #45926) * The Enterprise Monitor log was flooded with ERROR/WARN messages when the Service Manager was retrying for a `mysqld' connection: 2009-07-02 16:52:23,440 WARN [http-18080-4:com.mysql.sql] java.lang.Exception: MySQL server not running or accepting connections, retrying 30 times or 46 seconds, whichever expires first. Exception was: Communications link failure Last packet sent to the server was 0 ms ago. 2009-07-02 16:52:24,455 WARN [Purger:com.mysql.sql] java.lang.Exception: MySQL server not running or accepting connections, retrying 46 times or 151 seconds, whichever expires first. Exception was: Communications link failure Last packet sent to the server was 0 ms ago. 2009-07-02 16:52:25,471 WARN [http-18080-5:com.mysql.sql] java.lang.Exception: MySQL server not running or accepting connections, retrying 28 times or 34 seconds, whichever expires first. Exception was: Communications link failure Last packet sent to the server was 0 ms ago. 2009-07-02 16:52:26,377 WARN [http-18080-9:com.mysql.sql] java.lang.Exception: MySQL server not running or accepting connections, retrying 33 times or 64 seconds, whichever expires first. Exception was: Communications link failure Last packet sent to the server was 0 ms ago. (Bug #45924) * In the Enterprise Dashboard the icon file for `event.status.closed' was missing. The problem manifested differently in different browsers. In Internet Explorer 8 the UI cell was empty and no text was displayed. In Firefox 3 the text `event.status.closed' was displayed in the cell. (Bug #45872) * If the system time zone was different from that set in the Enterprise Dashboard, then there was inconsistency in the way times were displayed on the Query Analyzer page. Some times were displayed in the time zone of the system and some were displayed using the Dashboard time zone setting. (Bug #45858) * In Enterprise Dashboard, when a range on the graph in the `Graphs' tab was selected, the following error message was displayed: Error Message You do not have permissions to access this resource. E0211: PermissionDeniedException: [] com.mysql.merlin.ui.interceptors.AuthenticationInterceptor.intercept(AuthenticationInterce ptor.java:109) com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java :224) com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java :1) com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(UtilTimerStack.java:455) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:221) org.apache.struts2.impl.StrutsActionProxy.execute(StrutsActionProxy.java:50) org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:507) org.apache.struts2.dispatcher.FilterDispatcher.doFilter(FilterDispatcher.java:421) org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.ja va:235) org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) net.sf.ehcache.constructs.web.filter.GzipFilter.doFilter(GzipFilter.java:81) net.sf.ehcache.constructs.web.filter.Filter.doFilter(Filter.java:92) org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.ja va:235) org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) com.mysql.util.RequestCounterFilter.doFilter(RequestCounterFilter.java:117) org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.ja va:235) org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) com.mysql.merlin.ui.filters.AccessLogFilter.doFilter(AccessLogFilter.java:56) org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.ja va:235) org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233) org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175) org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128) org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102) org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109) org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:263) org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:844) org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.jav a:584) org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447) java.lang.Thread.run(Unknown Source) (Bug #45836) * If both the `View Readme' and `Launch Monitor in browser' check boxes were selected on the last screen of the Monitor installer, the Dashboard was not brought up in a browser until after the window displaying the `readme' information was closed. (Bug #45795) * The Agent did not report all the rows from an explain plan where the plan had more than one row. The Dashboard would display information for the first row, but subsequent rows would display NULL. (Bug #45791) * Custom collections did not override standard collections. If a custom collection file was defined, and collections specified which were the same as the defaults but with some extensions, the custom collection did not appear to be processed and so did not override the default collection. (Bug #45755) * When the Service Manager was restarted, or if the Service Manager was turned off for a brief period, and then turned back on, some graphs, such as Database Activity, showed an erroneous spike in traffic. (Bug #45688) * Cry for help emails were not sent for events such as the monitored server running out of connections or disk space. In the past these had been sent for any error code < 1026. (Bug #45667) * If custom collection files were created for the Agent, and references added to the `agent-item-files' variable within the `mysql-monitor-agent.ini' file, on upgrade the following problems occurred: 1. The `agent-item-files' variable was overwritten, thereby removing the custom entry. 2. The custom files were deleted, if they were contained in the `share/' directory. (Bug #45655) * In the Enterprise Dashboard, when closing single or multiple Events the following exception was generated: Could not execute JDBC batch update org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:71) (Bug #45627) * In the Enterprise Dashboard, the icon displayed for each server on the `Settings', `Manage Servers' page was incorrectly located. This resulted in fewer servers being displayed per page. (Bug #45564) * In Enterprise Dashboard, when clicking `configure what's new' in the `What's New?' tab, an error occurred. This only happened when using Internet Explorer 8. (Bug #45478) * After the initial server installation a user may select OpenSSL native integration with Tomcat. This will modify the `apache-tomcat/lib' directory. However, subsequently running an upgrade installer overwrote the `apache-tomcat/lib' directory which had been modified during the OpenSSL native integration. (Bug #45432) * The query `SELECT * FROM 23lk4kj234;' was reported incorrectly in the Query Analyzer. (Bug #45431) * When an event was closed a `SUCCESS' SNMP trap was sent, rather than a `CLOSED' SNMP trap. (Bug #45376) * When MySQL Enterprise Monitor 1.3 was upgraded directly to 2.1, and having requested SSL in the upgrade dialog, SSL did not work in the upgraded Monitor. (Bug #45339) * When an event was closed, the row in the event table where the event entry was located had its check box disabled, even though the event now in that row was open. This happened regardless of whether the `Close' button, or the `close' link were used to close the event. (Bug #45250) * The Notifications list in the Schedules or Edit Schedules pop-ups listed the Notification Groups targets in the order in which they were created, not alphabetic order. (Bug #45169) * A small memory leak occurred in the agent when a connection attempt to the dashboard failed. This represented a problem if the agent was unable to connect to the dashboard for a long period of time, as each failure to connect would leak some more memory. (Bug #45164) * When disabling Query Analyzer while the two sub-options remain enabled for an individual agent, the analyzer, explain and other options would be logged by the agent as critical errors. Now, only the disabling of Query Analyzer is logged as a critical error. The Example Query and Example Explain options are reported as info errors. (Bug #45041) * The Agent attempted to obtain the Query Analyzer configuration before the Monitor server has created it. This resulted in the Agent generating the following critical error in the log: 2009-05-21 15:59:42: (critical) network-io.c:255: successfully reconnected to dashboard at http://agent:merlin@127.0.0.1:18080/heartbeat 2009-05-21 15:59:47: (critical) agent_mysqld.c:641: successfully connected to database at 127.0.0.1:13306 as user marcos (with password: YES) 2009-05-21 15:59:52: (critical) network-io.c:807: starting task 2 for mysql::server[8b1294a5-b40b-457c-b8d3-a834848dc1df] 2009-05-21 15:59:52: (critical) job_collect_lua.c:323: ...ql/enterprise/agent/share/mysql-proxy/items/quan.lua:505: GETing quan-config from http://agent:merlin@127.0.0.1:18080/v2/rest/instance/mysql/StatementAnalysisSupport/8b1294 a5-b40b-457c-b8d3-a834848dc1df failed with: 404 8b1294a5-b40b-457c-b8d3-a834848dc1df of type mysql.StatementAnalysisSupport not found 2009-05-21 16:00:00: (critical) (share/mysql-proxy/items/quan.lua:528) setting .analyze_queries for 8b1294a5-b40b-457c-b8d3-a834848dc1df to true 2009-05-21 16:00:00: (critical) (share/mysql-proxy/items/quan.lua:532) setting .auto_explain for 8b1294a5-b40b-457c-b8d3-a834848dc1df to true 2009-05-21 16:00:00: (critical) (share/mysql-proxy/items/quan.lua:536) setting .analyze_worst_queries for 8b1294a5-b40b-457c-b8d3-a834848dc1df to true 2009-05-21 16:00:00: (critical) (share/mysql-proxy/items/quan.lua:540) setting .auto_explain_min_exec_time_us for 8b1294a5-b40b-457c-b8d3-a834848dc1df to 500000 (Bug #45016) * If a migration from 1.3 to 2.0 was initiated and a new server created during the migration, but then deleted before migration was finished, the new server delete operation failed with an Null Pointer Exception (NPE). (Bug #44991) * If you have the environment variable `http_proxy' set within your environment, when connections from MySQL Enterprise Monitor Agent could be redirected to an external site, instead of sending them to the configured MySQL Enterprise Service Manager. You can disable this behavior by adding the contents of the `agent-mgmt-hostname' configuration option for MySQL Enterprise Monitor Agent to the `no_proxy' variable. (Bug #44893) * The regular expression used to parse the adaptive hash index section of `SHOW INNODB STATUS' for the cell size/used and node size did not function correctly for versions of monitored server greater than 5.1.28. This was because the section of the expression dealing with `cells used' was removed as part of Bug#36941. (Bug #44853) * The Rule `InnoDB Buffer Cache Hit Rate Not Optimal' in the `Memory Usage' Advisor did not contain an uptime check. This resulted in premature firing of an info event. (Bug #44770) * Any `JAVA_OPTS' configuration changes made in the `catalina.sh' file, such as `-Xmx', `-Xms', were overwritten when the upgrade installer was run. These values were used for customizing larger installations. (Bug #44740) * In the Advisor `Administration' the Rule `InnoDB Redo Logs Not Sized Correctly' did not fire correctly. The rule contained the expression: (%have_innodb% == "YES") && ((%innodb_log_file_size% * %innodb_log_files_in_group%) < LEAST(1073741824, (%innodb_buffer_pool_size% / 2))) This was incorrect and needed to be changed to: (%have_innodb% == "YES") && ((%innodb_log_file_size% * %innodb_log_files_in_group%) <= LEAST(1073741824, (%innodb_buffer_pool_size% / 2))) (Bug #44734) * If the Service Manager was set up to use an HTTP proxy, all traffic attempted to go through the proxy, including the connection to the `mysqld' server running the repository. (Bug #44729) * The recommendation for the rule `Table Cache Not Optimal' says: Recommended Action SET GLOBAL table_cache = (64 + 16); But an error was generated on executing that query: mysql> SET GLOBAL table_cache = (64 + 16); ERROR 1193 (HY000): Unknown system variable 'table_cache' mysql> select version(); +------------+ | version() | +------------+ | 5.1.31-log | +------------+ 1 row in set (0.01 sec) (Bug #44602) * In Enterprise Dashboard, clicking a query listed on the Query Analyzer page resulted in a delay of around 28 seconds before the pop-up was displayed. (Bug #44601) * The frequency shown on the `Advanced' tab of an `Event' pop-up was the default frequency for a rule and not the frequency actually scheduled. (Bug #44591) * Any changes made to the `config.properties' file, were overwritten by the upgrade installer. (Bug #44526) * If a customer was using their own SSL certificate, they entered that information in the `server.xml' file. However, running the upgrade installer caused `server.xml', and any custom certificates, to be replaced. (Bug #44525) * If you edited the `server.xml' file inside the `tomcat/conf/' folder, and changed the Tomcat port, running the upgrade installer did not show you the new port number, but the one you used at the installation time. It also did not remember that you had enabled SSL. (Bug #44444) * Editing an Advisor and selecting the `Use SNMP Traps' check box led to confusing behavior. Advisors appeared to be incorrectly enabled or disabled. (Bug #44387) * The Agent failed to correctly determine the state of the monitored server if the `thread-id', extracted from the client/server protocol, is greater than 2^32. In the case with a `thread-id' greater than 2^32, the agent incorrectly determined that it was monitoring a remote server. High values of `thread-id' occur when the monitored server has many connections, or if it has been running for an extended period of time. (Bug #44168) * The Mac OS X version of the Service Manager uses the system JRE. The system JRE loads the libraries located in `/Library/Java/Extensions'. As libraries in the extensions directory take precedence over other libraries, this caused conflicts when user extension libraries were installed there, as these would be used by the JRE when running Service Manager, instead of the shipped libraries. This happened when Java-related products were installed such as Connector/J, Spring, and Hibernate. This fix stops user-installed extension libraries from being used when the JRE runs the Service Manager, thus giving a `pristine' environment with no library collisions. (Bug #44157) * The `What's New' tab can no longer be hidden, as it now provides important information and updates about MySQL and MySQL Enterprise Monitor. (Bug #44107) * In the Enterprise Dashboard, when the frequency for a rule was changed in `Advisors', `Manage Rules', `edit', incorrect thresholds were saved, leading to erroneous alerts. (Bug #44102) * MySQL Enterprise Monitor installation sometimes failed, generating the following error: Installing Innitializing User accounts. (4/6) Error running /opt/mysql/enterprise/monitor/mysql/bin/mysql --defaults-file=/opt/mysql/enterprise/monitor/mysql/my.cnf -S /opt/mysql/enterprise/monitor/mysql/tmp/mysql.sock -u root -D mysql -e "update user set Password = PASSWORD('service_manager') where User = 'root'; update user set User = 'service_manager' where User = 'root';delete from user where User = '';flush privileges;" : ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/opt/mysql/enterprise/monitor/mysql/tmp/mysql.sock' (2) After displaying this error, the MySQL Enterprise Monitor installer reported that it had `completed', but the message displayed contained an error message string: Report2.SetInstallerVariable.errorsOnSQLStatementsText (Bug #44038) * In the Enterprise Dashboard, in the `Query Analyzer' tab, the monitored parameter was not handled correctly during collapse and expansion of the graph. For example, if the graph was monitoring CPU Utilization, and then collapsed and the parameter changed to Database Activity, the monitored parameter reverted to CPU Utilization when the graph was expanded again. (Bug #44029) * The upgrade installer overwrote any custom settings stored in `WEB-INF/config.properties'. For example it set the database host back to `localhost'. (Bug #44003) * Accessing the Query Analyzer tab caused a full table scan to take place on the MySQL Enterprise Monitor database. (Bug #43989) * Some SNMP managers could not detect `Application Error' SNMP notifications. This happened because some SNMP managers do not follow the protocol correctly. Some use the `DisplayString' length of 255 as the maximum `OctetString', but this is in fact unlimited in SMIv1 and 64k in SMIv2. To work around this issue it is possible to override the correct behavior to enable non-comformant SNMP Managers to detect all messages. This is achieved by overriding the `OctetString' maximum size by setting a MySQL Enterprise Monitor server property. This is done by entering SQL such as the following: INSERT INTO map_entries VALUES (1,'2048','snmp.octetstring'); In this example the value 2048 will be the maximum SNMP `OctetString' size that would sent in any SNMP traps. After setting this property the server will need to be restarted. Note that the value used may need adjusting depending on the behavior of the SNMP manager. (Bug #43970) * When updating an Agent from 2.0 to 2.1 the `mysql-monitor-agent.ini' was incorrectly updated. This happened if the Agent was configured to use SSL to connect to the Enterprise Dashboard, on a port other than 18443. The update installer caused any value specified for the port to be changed to 18443. This did not happen if the Agent was not using SSL. (Bug #43900) * The Enterprise Dashboard was running abnormally slowly. Clicking on a tab in the Dashboard, or selecting a server from the server tree resulted in a delay of approximately one minute before the results were displayed. (Bug #43866) * The Agent failed on Linux 32-bit systems with the following error: 2009-03-24 16:01:09: (debug) chassis.c:1091: current RLIMIT_NOFILE = 4398046512128 (hard: 577792033385921489) 2009-03-24 16:01:09: (debug) chassis.c:1095: trying to set new RLIMIT_NOFILE = 4398046519296 (hard: 577792033385921489) 2009-03-24 16:01:09: (critical) chassis.c:1097: could not raise RLIMIT_NOFILE to 8192, Invalid argument (22). Current limit still 13811918798715880448. 2009-03-24 16:01:09: (message) MySQL Monitor Agent 2.0.5.7153 started. This happened with the following environment: $ ./mysql-monitor-agent -V mysql-proxy 0.7.0 glib2: 2.16.3 libevent: 1.4.6-stable proxy: 0.7.0 monitor: 0.7.0 MySQL Monitor Agent(agent): 2.0.5.7153 admin: 0.7.0 $ cat /etc/redhat-release Red Hat Enterprise Linux ES release 3 (Taroon Update 5) $ uname -a Linux xxxx 2.4.21-32.0.1.ELsmp #1 SMP Tue May 17 17:52:23 EDT 2005 i686 i686 i386 GNU/Linux The same error also occurred on CentOS 5.2 32-bit systems. (Bug #43821) * The Replication Group was renamed back to its default name after a new topology was discovered. (Bug #43816) * A new topology was not discovered after the previous replication group was renamed. (Bug #43815) * On Unix systems, executing the command: ./mysqlmonitorctl.sh stop did not make sure that `mysqld' was shutdown before finishing. This resulted in a situation such as the following: # /opt/mysql/enterprise/monitor-2.0.0.7092/mysqlmonitorctl.sh stop Using CATALINA_BASE: /opt/mysql/enterprise/monitor/apache-tomcat Using CATALINA_HOME: /opt/mysql/enterprise/monitor/apache-tomcat Using CATALINA_TMPDIR: /opt/mysql/enterprise/monitor/apache-tomcat/temp Using JRE_HOME: /opt/mysql/enterprise/monitor-2.0.0.7092/java Stopping tomcat service ... [ OK ] /opt/mysql/enterprise/monitor-2.0.0.7092/mysqlmonitorctl.sh : mysql stopped However, running the following command a few minutes later showed that the MySQL server was still running: # /opt/mysql/enterprise/monitor-2.0.0.7092/mysqlmonitorctl.sh status MySQL Network MySQL is running MySQL Network Tomcat is not running (Bug #43803) * The MySQL Enterprise Monitor upgrade installer incorrectly replaced the `AdvisorScript.jar' in `/apache-tomcat/webapps/ROOT/WEB-INF/lib/' with the default Advisor JAR. (Bug #43773) * The SNMP trap source IP was always set to 127.0.0.1. (Bug #43738) * The advisor `Replication - Slave Has Login Accounts With Inappropriate Privileges' contained inappropriate advice information. The advice message generated was: Server: slave-01 Time: 2009-03-17 12:00:04 GMT Advisor: Replication - Slave Has Login Accounts With Inappropriate Privileges Problem Description Altering and dropping tables on a slave can break replication. Unless the slave also hosts non-replicated tables, there is no need for accounts with these privileges. Advice Revoke the global ALTER and DROP privileges from the following accounts on server slave-01 unless they are absolutely necessary: user_1@localhost, user_2@localhost Recommended Action REVOKE ALTER, DROP ON *.* FROM user_name@host_name; FLUSH PRIVILEGES; However, the problems with this advice were: 1. The server was configured `read_only' so it would not be possible to `DROP' or `ALTER' tables unless the user had `SUPER' privilege. 2. MySQL grants were replicated from the master and therefore appeared on the slave. Also, `read_only' ensured the slave could not be changed. (Bug #43701) * In Enterprise Dashboard, if on the `Monitor' page the `Configure Graphs' link was clicked, no changes made, and then the `Save' button clicked, then the following error was generated: U0023 You must provide a non-zero interval (Bug #43682) * The installer exited with a return code `0', even if an error was detected and reported to the user during the installation. .../mysqlmonitor-2.1.0.1015-linux-x86-64bit-installer.bin --mode unattended --installdir /data0/merlin/monitoring/2.1.0.1015/host/38080 --tomcatport 38080 --tomcatshutdownport 38503 --tomcatsslport 38443 --dbport 33300 --usessl 1 --adminuser **user** --adminpassword **pwd** Error running /data0/merlin/monitoring/2.1.0.1015/host/38080/mysql/bin/mysql --defaults-file=/data0/merlin/monitoring/2.1.0.1015/host/38080/mysql/my.cnf -S /data0/merlin/monitoring/2.1.0.1015/qa-merlin/38080/mysql/tmp/mysql.sock -u root -D mysql -e "update user set Password = PASSWORD('**pwd**') where User = 'root'; update user set User = '**user**' where User = 'root';delete from user where User = '';flush privileges;" : ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/data0/merlin/monitoring/2.1.0.1015/host/38080/mysql/tmp/mysql.sock' (2) (Bug #43676) * The Connections graph did not include information from the Thread Cache graph. Connections and Thread Cache were available as separate graphs but it was difficult to compare them. (Bug #43584) * If it was desired to look at MySQL Enterprise Monitor graphs for time spans of over 24 hours, you had to change from Interval to From/To mode, and specify a fixed From and To period. This was inconvenient compared to simply specifying a greater interval. (Bug #43564) * The agent created the `mysql.inventory' table with an engine type of InnoDB, instead of MyISAM, when InnoDB was specified as the default engine type in `my.cnf'. This happened because the agent did not explicitly specify the table engine type to be of MyISAM. (Bug #43551) * When a trailing space, or tab character, was added at the end of a parameter in the `config.properties' file, MySQL Enterprise Monitor failed to start and generated the following errors in log: ERROR [Thread-1:org.springframework.web.context.ContextLoader] Context initialization failed ... Caused by: java.sql.SQLException: Illegal connection port value '13306' ... Resolving the problem required detailed log analysis because the configuration file did not show any apparent problems. (Bug #43540) * The MySQL Enterprise Monitor installer failed to install correctly due to insufficient disk space, even though the installer calculated there was sufficient disk space for the installation. This was due to the installer having out of date information regarding disk space requirements. (Bug #43538) * After removing enough servers to bring the host count back down to the number covered in the subscription, the Subscription Warnings reflected the new number. However, the warning message displayed: You are currently monitoring 1 host, however your subscription covers only 1. Your subscription needs to be updated to cover at least 0 additional hosts. Instead of displaying: Your subscription is up-to-date You have no warnings at this time. The former message resulted in confusion. (Bug #43163) * If a host was not a slave during the initial discovery phase, then it would not be displayed in the Replication tab if it subsequently became a slave. This was because after the initial discovery phase, if a host did not have `slavestatus' present, no subsequent checks were made to check for the host being a slave. It was therefore missed for the purposes of replication discovery and never showed in the Replication tab. (Bug #42997) * In the Enterprise Dashboard it is only possible to delete monitored servers if they are stopped. Monitored servers can be deleted in `Settings', `Manage Servers'. However, if after stopping the Agent, the Dashboard was not refreshed and the agent was started again, an error was generated saying that the agent was running and could therefore not be deleted. Although correct, this was confusing as the Dashboard showed the Agent as stopped but the delete operation error message showed the Agent as running. (Bug #42983) * Heat Chart rules could not be disabled or unscheduled. (Bug #42932) * There were four columns added to the *Note `SHOW SLAVE STATUS': show-slave-status. query in MySQL Server 5.1: `Last_IO_Errno', `Last_IO_Error', `Last_SQL_Errno', and `Last_SQL_Error'. However, these were not displayed within the Replication tab. (Bug #42811) * Agent IP address was not included in SNMP traps. It was also not possible to set these Agent IP addresses through a configuration, which would have been useful for situations where the Agent could not determine the monitored server IP address, such as when virtual IP addresses were used. (Bug #42703) * The Agent would not reconnect to a monitored database if it was started when the monitored server was down. The agent log contained the following error: Can't connect to MySQL server on '127.0.0.1' (0) (mysql-errno = 2003) The agent only sent OS data to the Dashboard. Further, when the monitored server was later started, no attempts to reconnect were logged. The problem could be worked around by restarting the agent when the monitored server was running again. (Bug #42581) * The installer used to upgrade from version 1.3 corrupted passwords containing the `?' character. (Bug #42452) * Sun multi-core processors caused all cores to be reported on the meta information page. The larger T-series SPARC processors have 32+ cores. This caused the meta information page in the Dashboard to scroll as it reported each one. (Bug #42355) * The username field for new users was populated by the last username used. When creating a new user for the second time in Dashboard, the previously created username appeared in the dialog. (Bug #42314) * The Agent shut down if the wrong username/password was given in the Service Manager. This happened on a fresh installation, when running the Service Manager through the Proxy. When `Complete' was clicked to finish the installation the error `Cannot open connection' was displayed. The Agent log also contained the following errors: 2009-01-20 15:54:16: (critical) <-- received HTTP-status: 401 (failed) for 'http://agent:mysql@127.0.0.1:8080/Monitor2/heartbeat': password are wrong 2009-01-20 15:54:16: (critical) shutting down normally 2009-01-20 15:54:19: (critical) <-- received HTTP-status: 401 (failed) for 'http://agent:mysql@127.0.0.1:8080/Monitor2/heartbeat': password are wrong 2009-01-20 15:54:19: (critical) shutting down normally (Bug #42228) * The `my.cnf' file for the Enterprise Monitor internal database had the following configuration item: innodb_autoextend_increment = 50M This generated the error: 16:36:23 [Warning] option 'innodb_autoextend_increment': unsigned value 52428800 adjusted to 1000 This variable is interpreted as being specified in MB, so 50M would be 50 TB. Such a high value results in the variable being adjusted to 1000 MB. The value in the configuration file should be: innodb_autoextend_increment = 50 (Bug #42096) * A number of Advisor rules had advice text that had not been translated into Japanese. The Advisors that contained untranslated rules included Performance, Schema and Security. (Bug #42067) * Using a long interval for the long data collection purging (such as 6 weeks), and a short interval for the query analysis purging (such as 1 week) caused the Query Analyzer purge `EXPLAIN' for the `INSERT' ... `SELECT' into the `temp_dc_ng_*_now' table to perform a full scan on the `dc_ng_*_now.end_time' index. For example: explain SELECT instance_attribute_id, end_time, end_time FROM dc_ng_long_now JOIN inventory_instance_attributes USING (instance_attribute_id) JOIN inventory_instances USING (instance_id) WHERE dc_ng_long_now.end_time <= 1230814870074 AND dc_ng_long_now.instance_attribute_id AND type_id in (8, 9, 7, 6) ORDER BY dc_ng_long_now.end_time ASC LIMIT 10000\G *************************** 1. row *************************** id: 1 select_type: SIMPLE table: dc_ng_long_now type: range possible_keys: PRIMARY,end_time key: end_time key_len: 8 ref: NULL rows: 8205369 Extra: Using where; Using index *************************** 2. row *************************** id: 1 select_type: SIMPLE table: inventory_instance_attributes type: eq_ref possible_keys: PRIMARY,instance_id key: PRIMARY key_len: 4 ref: mem.dc_ng_long_now.instance_attribute_id rows: 1 Extra: *************************** 3. row *************************** id: 1 select_type: SIMPLE table: inventory_instances type: eq_ref possible_keys: PRIMARY,FKD4320F5BBDD9C29B key: PRIMARY key_len: 4 ref: mem.inventory_instance_attributes.instance_id rows: 1 Extra: Using where 3 rows in set (0.55 sec) (Bug #42061) * `OM_REFRESH' was not supported by MySQL Proxy, it caused an `abort()'. shell> ./mysql-proxy --proxy-backend-addresses=192.168.250.3:3306 network-mysqld-proxy.c.3524: COM_(0x07) is not handled Aborted (core dumped) (gdb) bt 0x00b1b402 in ?? () 0x00cbaf30 in raise () from /lib/i686/nosegneg/libc.so.6 0x00cbc811 in abort () from /lib/i686/nosegneg/libc.so.6 0x08061efc in IA__g_logv at gmessages.c:497 0x08061f66 in IA__g_log at gmessages.c:517 0x08054645 in proxy_read_query_result at network-mysqld-proxy.c:3522 0x0804c5f4 in plugin_call at network-mysqld.c:977 0x0804d45a in network_mysqld_con_handle at network-mysqld.c:1520 0x08057cb9 in event_process_active (base=0x978b260) at event.c:331 0x08057e64 in event_base_loop (base=0x978b260, flags=0) at event.c:449 0x08057d1c in event_base_dispatch (event_base=0x978b260) at event.c:351 0x0804d9d0 in network_mysqld_thread (_srv=0x9789008) at network-mysqld.c:1768 0x0804b84a in main (argc=1, argv=0xbfc4fe84) at mysql-proxy.c:615 (Bug #41991) * The MySQL Enterprise Monitor file `my.cnf' specified an initial size of 500M for the central tablespace. However, `innodb_file_per_table' was used as well, resulting in approximately 500M of space being potentially wasted. (Bug #41967) * It was not possible to change any settings related to Query Analyzer unless at least one MySQL server was already being monitored. (Bug #41875) * The advisor `User Has Rights To Database That Does Not Exist' generated erroneous alerts. If a database was created with an `_' character in the name, and then user privileges granted to this database using the escaped character sequence `\_' to prevent wildcards, then the advisor generates an error stating there is no database for the privilege. For example, if the following is carried out on the monitored server: CREATE DATABASE test_foo; GRANT SELECT ON `test\_foo`.* to testuser@'localhost' identified by 'test'; then the advisor warns that these users have rights to a database that does not exist: ''@'%' on DB test_%, 'test'@'localhost' on DB test_foo, 'testuser'@'localhost' on DB test_foo (Bug #41717) * In the Enterprise Dashboard, when a new server group was clicked in the main tab an error message was generated. On checking the Monitor log there were many error messages related to lock timeouts and having to retry transactions. This problem occurred after enabling purging of the Repository. (Bug #41461) * Running the Service Manager on Mac OS X and monitoring two servers with two agents for at least 16 hours caused the Java process to use 2.08 GB of memory. (Bug #41438) * After an error was generated due to an incorrect password while trying to create a new user, the following error was obtained when subsequently attempting to create a valid new user: U0002 You must log in to access the requested resource (Bug #41384) * SNMP trap messages were sending 127.0.0.1 as the IP address, and there was no feature to enable the user to configure the IP address contained in the SNMP message, which would have been useful for troubleshooting. (Bug #41361) * Allowing the heat chart rules to be set to unscheduled caused the user interface to appear broken. (Bug #41312) * Data in the agent resource usage graphs (CPU, RAM) stopped after a full install of a new agent monitoring the same database was carried out. Usage history was available across agent versions for all graphs except the agent resource usage graphs. (Bug #41249) * Graphs were incorrect for data that did not change. The graphs appeared as if no data had been gathered. The Hit Ratios graph had gaps in it where there had not been any activity on the parameters being monitored. For instance, if MyISAM tables were not used, then no Key Cache hit ratio series was plotted, even though the variables were still being collected. (Bug #41232) * The generic Linux IA64 glibc2.3 Agent installer was missing from the build. (Bug #41224) * When creating a new Database Administrator user in FireFox 2 the following error message was generated: U0002 You must log in to access the requested resource. This occurred in a new installation using the default administrator account. No Query Analysis permissions were given. However, the operation worked correctly using the Safari web browser. (Bug #41032) * The Enterprise Dashboard displayed a blank entry for `Disk Space' in the Meta Info area. This happened on Open Solaris 2008.05. This problem only occurred when using the ZFS file system. (Bug #40907) * The configuration for Query Analyzer that sets the default for all servers (using the `Make this the default for all new servers' check box) could still applied even when the dialog box was canceled. (Bug #40828) * The `Manage Servers' page did not refresh in a manner consistent with other pages. This meant that changes to configuration made by others would not be reflected on the page. Also, changes in the status of the servers were not displayed automatically. (Bug #40792) * The agent installer for HP-UX 11.11 would fail to execute correctly. (Bug #40568, Bug #40566, Bug #37508) * The graphs for Thread Cache, Connections and Temporary Tables contained incorrect Japanese translations on their Y axis. The Japanese displayed `total connection time (min)' when it should have displayed something else. For example, the Thread Cache graph should have displayed `total/min'. (Bug #40413) * If the MySQL Enterprise Monitor Agent was unable to execute an `EXPLAIN' on a query, it would report an empty SQL query. The agent will now report the query hash value, which can be used to identify the original query by examining the repository. (Bug #40353) * The agent installer for Solaris 8 x86 32-bit was missing. (Bug #40248) * Even though Query Analysis was disabled through the user interface, the queries that go through the agent were still being collected. When Query Analysis was turned back on in the user interface, those queries were then displayed. (Bug #40032) * The Enterprise Dashboard did not display OS data if the Agent was changed from remote to local monitoring. (Bug #39954) * The agent crashed if `ssh-keygen' was not present and if a wireless card was being used instead of an Ethernet card. This only affected Unix based systems, it did not affect Microsoft Windows. (Bug #39938) * On Mac OS X when a server had more than 4GB RAM available the memory advisor was still triggered. This appeared to be due to an overflowing value. (Bug #39757) * The Agent received a critical error but did not terminate as expected. The critical error generated was: 2008-09-23 09:35:02: (critical) agent_mysqld.c:139: mysql_real_query() failed: Can't find file: './mysql/inventory.frm' (errno: 13) (errno=1017) (Bug #39603) * Alerts sent from MySQL Enterprise Monitor used the GMT timezone, for example: Time: 2008-09-17 19:41:08 GMT That was not convenient for users, as their timezones may not have been GMT. (Bug #39504) * The Agent running on AIX 5.3 did not report CPU data or RAM size, causing the Enterprise Dashboard to crash with a Null Pointer Exception. (Bug #38001) * The MySQL Enterprise Monitor upgrade installer replaced the `my.cnf' file. This resulted in the loss of any changes that had been made to the configuration file. (Bug #36528) * In the Enterprise Dashboard, on the `Graphs' page, the interface for selecting time intervals was not convenient, and it required multiple clicks to select the desired interval. This was fixed by adding a selection of pre-determined time intervals. (Bug #34556) * Auto-generated replication group names were not translated into Japanese. (Bug #32155) * If the `On Save send test trap' check box was checked when the `Save' button was clicked and the locale was set to Japanese, an error occurred. The orange error banner was displayed at the top of the page with the error message in Japanese. (Bug #32069) * The Enterprise Dashboard could communicate with https://enterprise.mysql.com using the customer username and password to download the license key and advisor bundle. However, it could not make use of a proxy to do so. This was a problem as many corporate firewalls required the use of a proxy for all HTTP and HTTPS traffic. The work around of having to manually download license keys and advisor bundles by hand was inconvenient. (Bug #31507) * The agent log does not include a specific note of when the monitoring by the agent was started. An entry `AgentMonitoringService started' is now added to the log. (Bug #30609) * When the Agent was started as a service on Windows for the first time, the name in the Task Manager window was `MYSQL-~1.EXE'. This occurred whether the Agent was started from within the installer or from the Start Menu. If the service was restarted, the Agent's name changed to the correct value, `mysql-service-agent.exe'. (Bug #30166) * When configuring a graph, setting a to date to a value prior to the from date, or the from date to a value after the to date will not automatically switch the dates when `Update' is pressed. (Bug #28473) * In the Enterprise Dashboard, the user interface permitted you to close an already closed event. This happened if multiple instances of the `Events' tab were created. It was possible to close an event with resolution notes in one instance, and then close the same event again with a different set of resolution notes in the other instance. However, on review, the resolution notes and event closure time stamp recorded, were those of the first closure. (Bug #24107) * When upgrading a monitored server, the information and configuration of the server would not be updated, leading to rules not being executed or applied correctly. Server's are now re-inventoried according to the specified schedule. For more information, see Remote Server Inventory Schedule (http://dev.mysql.com/doc/mysql-monitor/2.1/en/mem-global-settings.html#mem-config-reinventory). (Bug #24068) * The Dynamic Link Library (DLL) `libxml2.dll' did not contain version resources. This meant version information was not available to be displayed when the file was examined in Windows Explorer. (Bug #23948) * It was not possible to rename a notification group. (Bug #22962) * Failures by MySQL Enterprise Service Manager to send warning emails are now reported both in the logs and in the MySQL Enterprise Dashboard within the `Product Info' section of the `Settings' page. For more information, see The Product Information Screen (http://dev.mysql.com/doc/mysql-monitor/2.1/en/mem-dashboard-settings.html#mem-product-info). (Bug #20478)  File: manual.info, Node: connector-odbc-news, Next: connector-net-news, Prev: mem-news, Up: news D.3 MySQL Connector/ODBC (MyODBC) Change History ================================================ * Menu: * connector-odbc-news-5-1-9:: Changes in MySQL Connector/ODBC 5.1.9 (Not released yet) * connector-odbc-news-5-1-8:: Changes in MySQL Connector/ODBC 5.1.8 (07 November 2010) * connector-odbc-news-5-1-7:: Changes in MySQL Connector/ODBC 5.1.7 (24 August 2010) * connector-odbc-news-5-1-6:: Changes in MySQL Connector/ODBC 5.1.6 (09 November 2009) * connector-odbc-news-5-1-5:: Changes in MySQL Connector/ODBC 5.1.5 (18 August 2008) * connector-odbc-news-5-1-4:: Changes in MySQL Connector/ODBC 5.1.4 (15 April 2008) * connector-odbc-news-5-1-3:: Changes in MySQL Connector/ODBC 5.1.3 (26 March 2008) * connector-odbc-news-5-1-2:: Changes in MySQL Connector/ODBC 5.1.2 (13 February 2008) * connector-odbc-news-5-1-1:: Changes in MySQL Connector/ODBC 5.1.1 (13 December 2007) * connector-odbc-news-5-1-0:: Changes in MySQL Connector/ODBC 5.1.0 (10 September 2007) * connector-odbc-news-5-0-12:: Changes in MySQL Connector/ODBC 5.0.12 (Never released) * connector-odbc-news-5-0-11:: Changes in MySQL Connector/ODBC 5.0.11 (31 January 2007) * connector-odbc-news-5-0-10:: Changes in MySQL Connector/ODBC 5.0.10 (14 December 2006) * connector-odbc-news-5-0-9:: Changes in MySQL Connector/ODBC 5.0.9 (22 November 2006) * connector-odbc-news-5-0-8:: Changes in MySQL Connector/ODBC 5.0.8 (17 November 2006) * connector-odbc-news-5-0-7:: Changes in MySQL Connector/ODBC 5.0.7 (08 November 2006) * connector-odbc-news-5-0-6:: Changes in MySQL Connector/ODBC 5.0.6 (03 November 2006) * connector-odbc-news-5-0-5:: Changes in MySQL Connector/ODBC 5.0.5 (17 October 2006) * connector-odbc-news-5-0-3:: Changes in Connector/ODBC 5.0.3 (Connector/ODBC 5.0 Alpha 3) (20 June 2006) * connector-odbc-news-5-0-2:: Changes in Connector/ODBC 5.0.2 (Never released) * connector-odbc-news-5-0-1:: Changes in Connector/ODBC 5.0.1 (Connector/ODBC 5.0 Alpha 2) (05 June 2006) * connector-odbc-news-3-51-28:: Changes in MySQL Connector/ODBC 3.51.28 (09 February 2011) * connector-odbc-news-3-51-27:: Changes in MySQL Connector/ODBC 3.51.27 (20 November 2008) * connector-odbc-news-3-51-26:: Changes in MySQL Connector/ODBC 3.51.26 (07 July 2008) * connector-odbc-news-3-51-25:: Changes in MySQL Connector/ODBC 3.51.25 (11 April 2008) * connector-odbc-news-3-51-24:: Changes in MySQL Connector/ODBC 3.51.24 (14 March 2008) * connector-odbc-news-3-51-23:: Changes in MySQL Connector/ODBC 3.51.23 (09 January 2008) * connector-odbc-news-3-51-22:: Changes in MySQL Connector/ODBC 3.51.22 (13 November 2007) * connector-odbc-news-3-51-21:: Changes in MySQL Connector/ODBC 3.51.21 (08 October 2007) * connector-odbc-news-3-51-20:: Changes in MySQL Connector/ODBC 3.51.20 (10 September 2007) * connector-odbc-news-3-51-19:: Changes in MySQL Connector/ODBC 3.51.19 (10 August 2007) * connector-odbc-news-3-51-18:: Changes in MySQL Connector/ODBC 3.51.18 (08 August 2007) * connector-odbc-news-3-51-17:: Changes in MySQL Connector/ODBC 3.51.17 (14 July 2007) * connector-odbc-news-3-51-16:: Changes in MySQL Connector/ODBC 3.51.16 (14 June 2007) * connector-odbc-news-3-51-15:: Changes in MySQL Connector/ODBC 3.51.15 (07 May 2007) * connector-odbc-news-3-51-14:: Changes in MySQL Connector/ODBC 3.51.14 (08 March 2007) * connector-odbc-news-3-51-13:: Changes in MySQL Connector/ODBC 3.51.13 (Never released) * connector-odbc-news-3-51-12:: Changes in MySQL Connector/ODBC 3.51.12 (11 February 2005) * connector-odbc-news-3-51-11:: Changes in MySQL Connector/ODBC 3.51.11 (28 January 2005)  File: manual.info, Node: connector-odbc-news-5-1-9, Next: connector-odbc-news-5-1-8, Prev: connector-odbc-news, Up: connector-odbc-news D.3.1 Changes in MySQL Connector/ODBC 5.1.9 (Not released yet) -------------------------------------------------------------- *Bugs fixed:* * When executing the `SQLProcedureColumns()' ODBC function, the driver reported the following error: MySQL server does not provide the requested information (Bug #50400) * When using MySQL Connector/ODBC to fetch data, if a `net_write_timeout' condition occurred, the operation returned the standard "end of data" status, rather than an error. (Bug #39878)  File: manual.info, Node: connector-odbc-news-5-1-8, Next: connector-odbc-news-5-1-7, Prev: connector-odbc-news-5-1-9, Up: connector-odbc-news D.3.2 Changes in MySQL Connector/ODBC 5.1.8 (07 November 2010) -------------------------------------------------------------- *Functionality added or changed:* * Documentation in `.CHM' and `.HLP' format has been removed from the distribution. (Bug #56232) *Bugs fixed:* * For some procedure and parameter combinations `SQLProcedureColumns()' did not work correctly. For example, it could not return records for an existing procedure with correct parameters supplied. Further, it returned incorrect data for column 7, `TYPE_NAME'. For example, it returned `VARCHAR(20)' instead of `VARCHAR'. (Bug #57182) * The MySQL Connector/ODBC MSI installer did not set the `InstallLocation' value in the Microsoft Windows registry. (Bug #56978) * In bulk upload mode, `SQLExecute' would return `SQL_SUCCESS', even when the uploaded data contained errors, such as primary key duplication, and foreign key violation. (Bug #56804) * `SQLDescribeCol' and `SQLColAttribute' could not be called before `SQLExecute', if the query was parameterized and not all parameters were bound. Note, MSDN states that `For performance reasons, an application should not call `SQLColAttribute/SQLDescribeCol' before executing a statement.' However, it should still be possible to do so if performance reasons are not paramount. (Bug #56717) * When `SQLNumResultCols()' was called between `SQLPrepare()' and `SQLExecute()' the driver ran `SET @@sql_select_limit=1', which limited the resultset to just one row. (Bug #56677) * After installing MySQL Connector/ODBC, the system DSN created could not be configured or deleted. An error dialog was displayed, showing the error message `Invalid attribute string'. In this case the problem was due to the fact that the driver could not parse the NULL-separated connection string. (Bug #56233) * When used after a call to `SQLTables()', `SQLRowCount()' did not return the correct value. (Bug #55870) * When attempting to install the latest Connector/ODBC 5.1.6 on Windows using the MSI, with an existing 5.1.x version already installed, the following error was generated: Another version of this product is already installed. Installation of this version cannot continue. To configure or remove the existing version of this product, use Add/Remove Programs on the Control Panel. Also, the version number displayed in the ODBC Data Source Administrator/Drivers tab did not get updated when removing or installing a new version of 5.1.x. (Bug #54314)  File: manual.info, Node: connector-odbc-news-5-1-7, Next: connector-odbc-news-5-1-6, Prev: connector-odbc-news-5-1-8, Up: connector-odbc-news D.3.3 Changes in MySQL Connector/ODBC 5.1.7 (24 August 2010) ------------------------------------------------------------ *Functionality added or changed:* * MySQL Connector/ODBC has been changed to support the `CLIENT_INTERACTIVE' flag. (Bug #48603) *Bugs fixed:* * `SQLColAttribute(SQL_DESC_PRECISION...)' function returned incorrect results for type identifiers that have a negative value: #define SQL_LONGVARCHAR (-1) returned 4294967295 #define SQL_BINARY (-2) returned 4294967294 #define SQL_VARBINARY (-3) returned 4294967293 #define SQL_LONGVARBINARY (-4) returned 4294967292 #define SQL_BIGINT (-5) returned 4294967291 #define SQL_TINYINT (-6) returned 4294967290 #define SQL_BIT (-7) returned 4294967289 They were returned as 32-bit unsigned integer values. This only happened on 64-bit Linux. (Bug #55024) * `SQLColAttribute' for `SQL_DESC_OCTET_LENGTH' returned length including terminating null byte. It should not have included the null byte. (Bug #54206) * The `SQLColumns' function returned the incorrect transfer octet length into the column `BUFFER_LENGTH' for `DECIMAL' type. (Bug #53235) * `SQLForeignKeys()' did not return the correct information. The list of foreign keys in other tables should not have included foreign keys that point to unique constraints in the specified table. (Bug #51422) * In contrast to all other ODBC catalog functions `SQLTablePrivileges' required the user to have `SELECT' privilege on MySQL schemata, otherwise the function returned with an error: SQL Error. Native Code: 1142, SQLState: HY000, Return Code: -1 [MySQL][ODBC 5.1 Driver][mysqld-5.0.67-community-nt]SELECT command denied to user 'repadmin'@'localhost' for table 'tables_priv' [Error][SQL Error]Error executing SQLTablePrivileges for object cat: myrep, object Name: xxxxxxxxxx (Bug #50195) * MySQL Connector/ODBC manually added a `LIMIT' clause to the end of certain SQL statements, causing errors for statements that contained code that should be positioned after the `LIMIT' clause. (Bug #49726) * If `NO_BACKSLASH_ESCAPES' mode was used on a server, escaping binary data led to server query parsing errors. (Bug #49029) * Bulk upload operations did not work for queries that used parameters. (Bug #48310) * Retrieval of the current catalog at the moment when a connection was not ready, such as when the connection had been broken or when not all pending results had been processed, resulted in the application crashing. (Bug #46910) * Describing a view or table caused SQLPrepare to prefetch table data. For large tables this created an intolerable performance hit. (Bug #46411) * If an application was invoked by the root user, `SQLDriverConnect()' was not able to use the username and password in the connection string to connect to the database. (Bug #45378) * Calling `SQLColAttribute' on a date column did not set `SQL_DESC_DATETIME_INTERVAL_CODE'. `SQLColAttribute' returned `SQL_SUCCESS' but the integer passed in was not set to `SQL_CODE_DATE'. (Bug #44576) * Conversions for many types were missing from the file `driver/info.c'. (Bug #43855) * The `SQLTables()' function required approximately two to four minutes to return the list of 400 tables in a database. The `SHOW TABLE STATUS' query used by `SQLTables()' was extremely slow for InnoDB tables with a large number of rows because the query was calculating the approximate number of rows in each table. Further, the results could not be cached due to non-deterministic nature of the result set (the row count was re-calculated every time), impacting performance further. (Bug #43664) * Executing `SQLForeignKeys' to get imported foreign keys for tables took an excessively long time. For example, getting imported foreign keys for 252 tables to determine parent/child dependencies took about 3 minutes and 14 seconds for the 5.1.5 driver, whereas it took 3 seconds for the 3.5x.x driver. (Bug #39562) * `SQLDescribeCol' returned incorrect column definitions for `SQLTables' result. (Bug #37621) * When opening `ADO.Recordset' from Microsoft Access 2003, a run-time error occurred: ErrNo: -2147467259 ErrMessage: Data provider or other service returned an E_FAIL status. (Bug #36996) * `SQLPrimaryKeysW' returned mangled strings for table name, column name and primary key name. (Bug #36441) * On Windows, the SOCKET parameter to the DSN was used as the named pipe name to connect to. This was not exposed in the Windows setup GUI. (Bug #34477) * MySQL Connector/ODBC returned a value of zero for a column with a non-zero value. This happened when the column had a data type of `BIT', and any numeric type was used in `SQLBindCol'. (Bug #32821) * Option for handling bad dates was not available in the GUI. (Bug #30539)  File: manual.info, Node: connector-odbc-news-5-1-6, Next: connector-odbc-news-5-1-5, Prev: connector-odbc-news-5-1-7, Up: connector-odbc-news D.3.4 Changes in MySQL Connector/ODBC 5.1.6 (09 November 2009) -------------------------------------------------------------- *Functionality added or changed:* * In the MySQL Data Source Configuration dialog, an excessive number of tabs were required to navigate to selection of a database. MySQL Connector/ODBC has been changed to make the tab order more practical, thereby enabling faster configuration of a Data Source. (Bug #42905) *Bugs fixed:* * An error randomly occurred on Windows 2003 Servers (German language Version) serving classic ASP scripts on IIS6 MDAC version 2.8 SP2 on Windows 2003 SP2. The application connected to MySQL Server 5.0.44-log with a charset of UTF-8 Unicode (utf8). The MySQL server was running on Gentoo Linux. The script error occurred sporadically on the following line of code: SET my_conn = Server.CreateObject("ADODB.Connection") my_conn.Open ConnString <- ERROR The connection was either a DSN or the explicit connection string: Driver={MySQL ODBC 5.1 Driver};SERVER=abc.abc.abc.abc;DATABASE=dbname;UID=uidname;PWD=pwdname;PORT=3306;OPTION=67108864; The error occurred on connections established using either a DNS or a connection string. When IISState and Debug Diagnostic Tool 1.0.0.152 was used to analyse the code, the following crash analysis was generated: MYODBC5!UTF16TOUTF32+6In 4640-1242788336.dmp the assembly instruction at myodbc5!utf16toutf32+6 in C:\Programme\MySQL\Connector ODBC 5.1\myodbc5.dll from MySQL AB has caused an access violation exception (0xC0000005) when trying to read from memory location 0x194dd000 on thread 33 (Bug #44971) * MySQL Connector/ODBC overwrote the query log. MySQL Connector/ODBC was changed to append the log, rather than overwrite it. (Bug #44965) * MySQL Connector/ODBC failed to build with MySQL 5.1.30 due to incorrect use of the data type `bool'. (Bug #42120) * Inserting a new record using `SQLSetPos' did not correspond to the database name specified in the `SELECT' statement when querying tables from databases other than the current one. `SQLSetPos' attempted to do the `INSERT' in the current database, but finished with a `SQL_ERROR' result and `Table does not exist' message from MySQL Server. (Bug #41946) * Calling `SQLDescribeCol()' with a NULL buffer and nonzero buffer length caused a crash. (Bug #41942) * MySQL Connector/ODBC updated some fields with random values, rather than with `NULL'. (Bug #41256) * When a column of type `DECIMAL' containing `NULL' was accessed, MySQL Connector/ODBC returned a 0 rather than a `NULL'. (Bug #41081) * In Access 97, when linking a table containing a `LONGTEXT' or `TEXT' field to a MySQL Connector/ODBC DSN, the fields were shown as `TEXT(255)' in the table structure. Data was therefore truncated to 255 characters. (Bug #40932) * Calling `SQLDriverConnect()' with a `NULL' pointer for the output buffer caused a crash if `SQL_DRIVER_NOPROMPT' was also specified: SQLDriverConnect(dbc, NULL, "DSN=myodbc5", SQL_NTS, NULL, 0, NULL, SQL_DRIVER_NOPROMPT) (Bug #40316) * Setting the ADO `Recordset' decimal field value to 44.56 resulted in an incorrect value of 445600.0000 being stored when the record set was updated with the `Update' method. (Bug #39961) * The `SQLTablesW' API gave incorrect results. For example, table name and table type were returned as `NULL' rather than as the correct values. (Bug #39957) * MyODBC would crash when a character set was being used on the server that was not supported in the client, for example cp1251: [MySQL][ODBC 5.1 Driver][mysqld-5.0.27-community-nt]Restricted data type attribute violation The fix causes MyODBC to return an error message instead of crashing. (Bug #39831) * Binding `SQL_C_BIT' to an `INTEGER' column did not work. The `sql_get_data()' function only worked correctly for `BOOLEAN' columns that corresponded to `SQL_C_BIT' buffers. (Bug #39644) * When the SQLTables method was called with `NULL' passed as the `tablename' parameter, only one row in the `resultset', with table name of `NULL' was returned, instead of all tables for the given database. (Bug #39561) * The `SQLGetInfo()' function returned 0 for `SQL_CATALOG_USAGE' information. (Bug #39560) * MyODBC Driver 5.1.5 was not able to connect if the connection string parameters contained spaces or tab symbols. For example, if the `SERVER' parameter was specified as `SERVER= localhost' instead of `SERVER=localhost' the following error message will be displayed: [MySQL][ODBC 5.1 Driver] Unknown MySQL server host ' localhost' (11001). (Bug #39085) * The pointer passed to the SQLDriverConnect method to retrieve the output connection string length was one greater than it should have been due to the inclusion of the NULL terminator. (Bug #38949) * Data-at-execution parameters were not supported during positioned update. This meant updating a long text field with a cursor update would erroneously set the value to null. This would lead to the error `Column 'column_name' cannot be null' while updating the database, even when `column_name' had been assigned a valid nonnull string. (Bug #37649) * The SQLDriverConnect method truncated the `OutputConnectionString' parameter to 52 characters. (Bug #37278) * The connection string option `Enable Auto-reconnect' did not work. When the connection failed, it could not be restored, and the errors generated were the same as if the option had not been selected. (Bug #37179) * Insertion of data into a `LONGTEXT' table field did not work. If such an attempt was made the corresponding field would be found to be empty on examination, or contain random characters. (Bug #36071) * No result record was returned for `SQLGetTypeInfo' for the `TIMESTAMP' data type. An application would receive the result `return code 100 (SQL_NO_DATA_FOUND)'. (Bug #30626) * It was not possible to use MySQL Connector/ODBC to connect to a server using SSL. The following error was generated: Runtime error '-2147467259 (80004005)': [MySQL][ODBC 3.51 Driver]SSL connection error. (Bug #29955) * When the `recordSet.Update' function was called to update an `adLongVarChar' field, the field was updated but the recordset was immediately lost. This happened with driver cursors, whether the cursor was opened in optimistic or pessimistic mode. When the next update was called the test code would exit with the following error: -2147467259 : Query-based update failed because the row to update could not be found. (Bug #26950) * Microsoft Access was not able to read `BIGINT' values properly from a table with just two columns of type `BIGINT' and `VARCHAR'. `#DELETE' appeared instead of the correct values. (Bug #17679)  File: manual.info, Node: connector-odbc-news-5-1-5, Next: connector-odbc-news-5-1-4, Prev: connector-odbc-news-5-1-6, Up: connector-odbc-news D.3.5 Changes in MySQL Connector/ODBC 5.1.5 (18 August 2008) ------------------------------------------------------------ *Bugs fixed:* * ODBC *Note `TIMESTAMP': datetime. string format is not handled properly by the MyODBC driver. When passing a *Note `TIMESTAMP': datetime. or *Note `DATE': datetime. to MyODBC, in the ODBC format: {d } or {ts }, the string that represents this is copied once into the SQL statement, and then added again, as an escaped string. (Bug #37342) * The connector failed to prompt for additional information required to create a DSN-less connection from an application such as Microsoft Excel. (Bug #37254) * `SQLDriverConnect' does not return `SQL_NO_DATA' on cancel. The ODBC documentation specifies that this method should return `SQL_NO_DATA' when the user cancels the dialog to connect. The connector, however, returns `SQL_ERROR'. (Bug #36293) * Assigning a string longer than 67 characters to the `TableType' parameter resulted in a buffer overrun when the `SQLTables()' function was called. (Bug #36275) * The ODBC connector randomly uses logon information stored in `odbc-profile', or prompts the user for connection information and ignores any settings stored in `odbc-profile'. (Bug #36203) * After having successfully established a connection, a crash occurs when calling `SQLProcedures()' followed by `SQLFreeStmt()', using the ODBC C API. (Bug #36069)  File: manual.info, Node: connector-odbc-news-5-1-4, Next: connector-odbc-news-5-1-3, Prev: connector-odbc-news-5-1-5, Up: connector-odbc-news D.3.6 Changes in MySQL Connector/ODBC 5.1.4 (15 April 2008) ----------------------------------------------------------- *Bugs fixed:* * Wrong result obtained when using `sum()' on a `decimal(8,2)' field type. (Bug #35920) * The driver installer could not create a new DSN if many other drivers were already installed. (Bug #35776) * The `SQLColAttribute()' function returned `SQL_TRUE' when querying the `SQL_DESC_FIXED_PREC_SCALE (SQL_COLUMN_MONEY)' attribute of a *Note `DECIMAL': numeric-types. column. Previously, the correct value of `SQL_FALSE' was returned; this is now again the case. (Bug #35581) * On Linux, `SQLGetDiagRec()' returned `SQL_SUCCESS' in cases when it should have returned `SQL_NO_DATA'. (Bug #33910) * The driver crashes ODBC Administrator on attempting to add a new DSN. (Bug #32057)  File: manual.info, Node: connector-odbc-news-5-1-3, Next: connector-odbc-news-5-1-2, Prev: connector-odbc-news-5-1-4, Up: connector-odbc-news D.3.7 Changes in MySQL Connector/ODBC 5.1.3 (26 March 2008) ----------------------------------------------------------- *Platform specific notes:* * *Important Change*: You must uninstall previous 5.1.x editions of MySQL Connector/ODBC before installing the new version. * The HP-UX 11.23 IA64 binary package does not include the GUI bits because of problems building Qt on that platform. * There is no binary package for Mac OS X on 64-bit PowerPC because Apple does not currently provide a 64-bit PowerPC version of iODBC. * The installer for 64-bit Windows installs both the 32-bit and 64-bit driver. Please note that Microsoft does not yet supply a 64-bit bridge from ADO to ODBC. *Bugs fixed:* * *Important Change*: In previous versions, the SSL certificate would automatically be verified when used as part of the MySQL Connector/ODBC connection. The default mode is now to ignore the verificate of certificates. To enforce verification of the SSL certificate during connection, use the `SSLVERIFY' DSN parameter, setting the value to 1. (Bug #29955, Bug #34648) * Inserting characters to a UTF8 table using surrogate pairs would fail and insert invalid data. (Bug #34672) * Installation of MySQL Connector/ODBC would fail because it was unable to uninstall a previous installed version. The file being requested would match an older release version than any installed version of the connector. (Bug #34522) * Using `SqlGetData' in combination with `SQL_C_WCHAR' would return overlapping data. (Bug #34429) * Descriptor records were not cleared correctly when calling `SQLFreeStmt(SQL_UNBIND)'. (Bug #34271) * The dropdown selection for databases on a server when creating a DSN was too small. The list size now automatically adjusts up to a maximum size of 20 potential databases. (Bug #33918) * Microsoft Access would be unable to use `DBEngine.RegisterDatabase' to create a DSN using the MySQL Connector/ODBC driver. (Bug #33825) * MySQL Connector/ODBC erroneously reported that it supported the `CAST()' and `CONVERT()' ODBC functions for parsing values in SQL statements, which could lead to bad SQL generation during a query. (Bug #33808) * Using a linked table in Access 2003 where the table has a *Note `BIGINT': numeric-types. column as the first column in the table, and is configured as the primary key, shows `#DELETED' for all rows of the table. (Bug #24535) * Updating a `RecordSet' when the query involves a *Note `BLOB': blob. field would fail. (Bug #19065)  File: manual.info, Node: connector-odbc-news-5-1-2, Next: connector-odbc-news-5-1-1, Prev: connector-odbc-news-5-1-3, Up: connector-odbc-news D.3.8 Changes in MySQL Connector/ODBC 5.1.2 (13 February 2008) -------------------------------------------------------------- MySQL Connector/ODBC 5.1.2-beta, a new version of the ODBC driver for the MySQL database management system, has been released. This release is the second beta (feature-complete) release of the new 5.1 series and is suitable for use with any MySQL server version since MySQL 4.1, including MySQL 5.0, 5.1, and 6.0. (It will not work with 4.0 or earlier releases.) Keep in mind that this is a beta release, and as with any other pre-production release, caution should be taken when installing on production level systems or systems with critical data. *Platform specific notes:* * The HP-UX 11.23 IA64 binary package does not include the GUI bits because of problems building Qt on that platform. * There is no binary package for Mac OS X on 64-bit PowerPC because Apple does not currently provide a 64-bit PowerPC version of iODBC. * The installer for 64-bit Windows installs both the 32-bit and 64-bit driver. Please note that Microsoft does not yet supply a 64-bit bridge from ADO to ODBC. * Due to differences with the installation process used on Windows and potential registry corruption, it is recommended that uninstall any existing versions of MySQL Connector/ODBC 5.1.x before upgrading. See also Bug #34571. *Functionality added or changed:* * Explicit descriptors are implemented. (Bug #32064) * A full implementation of SQLForeignKeys based on the information available from INFORMATION_SCHEMA in 5.0 and later versions of the server has been implemented. * Changed `SQL_ATTR_PARAMSET_SIZE' to return an error until support for it is implemented. * Disabled `MYSQL_OPT_SSL_VERIFY_SERVER_CERT' when using an SSL connection. * `SQLForeignKeys' uses `INFORMATION_SCHEMA' when it is available on the server, which enables more complete information to be returned. *Bugs fixed:* * The `SSLCIPHER' option would be incorrectly recorded within the SSL configuration on Windows. (Bug #33897) * Within the GUI interface, when connecting to a MySQL server on a nonstandard port, the connection test within the GUI would fail. The issue was related to incorrect parsing of numeric values within the DSN when the option was not configured as the last parameter within the DSN. (Bug #33822) * Specifying a nonexistent database name within the GUI dialog would result in an empty list, not an error. (Bug #33615) * When deleting rows from a static cursor, the cursor position would be incorrectly reported. (Bug #33388) * `SQLGetInfo()' reported characters for `SQL_SPECIAL_CHARACTERS' that were not encoded correctly. (Bug #33130) * Retrieving data from a *Note `BLOB': blob. column would fail within `SQLGetData'when the target data type was `SQL_C_WCHAR' due to incorrect handling of the character buffer. (Bug #32684) * Renaming an existing DSN entry would create a new entry with the new name without deleting the old entry. (Bug #31165) * Reading a *Note `TEXT': blob. column that had been used to store UTF8 data would result in the wrong information being returned during a query. (Bug #28617) * `SQLForeignKeys' would return an empty string for the schema columns instead of `NULL'. (Bug #19923) * When accessing column data, `FLAG_COLUMN_SIZE_S32' did not limit the octet length or display size reported for fields, causing problems with Microsoft Visual FoxPro. The list of ODBC functions that could have caused failures in Microsoft software when retrieving the length of *Note `LONGBLOB': blob. or *Note `LONGTEXT': blob. columns includes: * `SQLColumns' * `SQLColAttribute' * `SQLColAttributes' * `SQLDescribeCol' * `SQLSpecialColumns' (theoretically can have the same problem) (Bug #12805, Bug #30890) * Dynamic cursors on statements with parameters were not supported. (Bug #11846) * Evaluating a simple numeric expression when using the OLEDB for ODBC provider and ADO would return an error, instead of the result. (Bug #10128) * Adding or updating a row using `SQLSetPos()' on a result set with aliased columns would fail. (Bug #6157)  File: manual.info, Node: connector-odbc-news-5-1-1, Next: connector-odbc-news-5-1-0, Prev: connector-odbc-news-5-1-2, Up: connector-odbc-news D.3.9 Changes in MySQL Connector/ODBC 5.1.1 (13 December 2007) -------------------------------------------------------------- MySQL Connector/ODBC 5.1.1-beta, a new version of the ODBC driver for the MySQL database management system, has been released. This release is the first beta (feature-complete) release of the new 5.1 series and is suitable for use with any MySQL server version since MySQL 4.1, including MySQL 5.0, 5.1, and 6.0. (It will not work with 4.0 or earlier releases.) Keep in mind that this is a beta release, and as with any other pre-production release, caution should be taken when installing on production level systems or systems with critical data. Includes changes from *Note Connector/ODBC 3.51.21: connector-odbc-news-3-51-21. and *Note 3.51.22: connector-odbc-news-3-51-22. Built using MySQL 5.0.52. *Platform specific notes:* * The HP-UX 11.23 IA64 binary package does not include the GUI bits because of problems building Qt on that platform. * There is no binary package for Mac OS X on 64-bit PowerPC because Apple does not currently provide a 64-bit PowerPC version of iODBC. * The installer for 64-bit Windows installs both the 32-bit and 64-bit driver. Please note that Microsoft does not yet supply a 64-bit bridge from ADO to ODBC. * Due to differences with the installation process used on Windows and potential registry corruption, it is recommended that uninstall any existing versions of MySQL Connector/ODBC 5.1.x before upgrading. See also Bug #34571. *Functionality added or changed:* * *Incompatible Change*: Replaced myodbc3i (now myodbc-installer) with MySQL Connector/ODBC 5.0 version. * *Incompatible Change*: Removed monitor (myodbc3m) and dsn-editor (myodbc3c). * *Incompatible Change*: Do not permit `SET NAMES' in initial statement and in executed statements. * A wrapper for the `SQLGetPrivateProfileStringW()' function, which is required for Unicode support, has been created. This function is missing from the unixODBC driver manager. (Bug #32685) * Added MSI installer for Windows 64-bit. (Bug #31510) * Implemented support for `SQLCancel()'. (Bug #15601) * Added support for `SQL_NUMERIC_STRUCT'. (Bug #3028, Bug #24920) * Removed nonthreadsafe configuration of the driver. The driver is now always built against the threadsafe version of libmysql. * Implemented native Windows setup library * Replaced the internal library which handles creation and loading of DSN information. The new library, which was originally a part of MySQL Connector/ODBC 5.0, supports Unicode option values. * The Windows installer now places files in a subdirectory of the `Program Files' directory instead of the Windows system directory. *Bugs fixed:* * The `SET NAMES' statement has been disabled because it causes problems in the ODBC driver when determining the current client character set. (Bug #32596) * `SQLDescribeColW' returned UTF-8 column as `SQL_VARCHAR' instead of `SQL_WVARCHAR'. (Bug #32161) * ADO was unable to open record set using dynamic cursor. (Bug #32014) * ADO applications would not open a `RecordSet' that contained a *Note `DECIMAL': numeric-types. field. (Bug #31720) * Memory usage would increase considerably. (Bug #31115) * SQL statements are limited to 64KB. (Bug #30983, Bug #30984) * `SQLSetPos' with `SQL_DELETE' advances dynamic cursor incorrectly. (Bug #29765) * Using an ODBC prepared statement with bound columns would produce an empty result set when called immediately after inserting a row into a table. (Bug #29239) * ADO Not possible to update a client side cursor. (Bug #27961) * Recordset `Update()' fails when using `adUseClient' cursor. (Bug #26985) * MySQL Connector/ODBC would fail to connect to the server if the password contained certain characters, including the semicolon and other punctuation marks. (Bug #16178) * Fixed `SQL_ATTR_PARAM_BIND_OFFSET', and fixed row offsets to work with updatable cursors. * `SQLSetConnectAttr()' did not clear previous errors, possibly confusing `SQLError()'. * `SQLError()' incorrectly cleared the error information, making it unavailable from subsequent calls to `SQLGetDiagRec()'. * NULL pointers passed to `SQLGetInfo()' could result in a crash. * `SQL_ODBC_SQL_CONFORMANCE' was not handled by `SQLGetInfo()'. * `SQLCopyDesc()' did not correctly copy all records. * Diagnostics were not correctly cleared on connection and environment handles.  File: manual.info, Node: connector-odbc-news-5-1-0, Next: connector-odbc-news-5-0-12, Prev: connector-odbc-news-5-1-1, Up: connector-odbc-news D.3.10 Changes in MySQL Connector/ODBC 5.1.0 (10 September 2007) ---------------------------------------------------------------- This release is the first of the new 5.1 series and is suitable for use with any MySQL server version since MySQL 4.1, including MySQL 5.0, 5.1, and 6.0. (It will not work with 4.0 or earlier releases.) Keep in mind that this is a alpha release, and as with any other pre-production release, caution should be taken when installing on production level systems or systems with critical data. Not all of the features planned for the final Connector/ODBC 5.1 release are implemented. Functionality is based on Connector/ODBC 3.51.20. *Platform specific notes:* * The HP-UX 11.23 IA64 binary package does not include the GUI bits because of problems building Qt on that platform. * There is no binary package for Mac OS X on 64-bit PowerPC because Apple does not currently provide a 64-bit PowerPC version of iODBC. * There are no installer packages for Microsoft Windows x64 Edition. * Due to differences with the installation process used on Windows and potential registry corruption, it is recommended that uninstall any existing versions of MySQL Connector/ODBC 5.1.x before upgrading. See also Bug #34571. *Functionality added or changed:* * Added support for Unicode functions (`SQLConnectW', etc). * Added descriptor support (`SQLGetDescField', `SQLGetDescRec', etc). * Added support for `SQL_C_WCHAR'.  File: manual.info, Node: connector-odbc-news-5-0-12, Next: connector-odbc-news-5-0-11, Prev: connector-odbc-news-5-1-0, Up: connector-odbc-news D.3.11 Changes in MySQL Connector/ODBC 5.0.12 (Never released) -------------------------------------------------------------- *Note*: Development on Connector/ODBC 5.0.x has ceased. New features and functionality will be incorporated into Connector/ODBC 5.1. *Bugs fixed:* * Inserting `NULL' values into a *Note `DATETIME': datetime. column from Access reports an error. (Bug #27896) * Tables with *Note `TEXT': blob. columns would be incorrectly identified, returning an `Unknown SQL type - 65535' error. (Bug #20127)  File: manual.info, Node: connector-odbc-news-5-0-11, Next: connector-odbc-news-5-0-10, Prev: connector-odbc-news-5-0-12, Up: connector-odbc-news D.3.12 Changes in MySQL Connector/ODBC 5.0.11 (31 January 2007) --------------------------------------------------------------- *Functionality added or changed:* * Added support for ODBC v2 statement options using attributes. * Driver now builds and is partially tested under Linux with the iODBC driver manager. *Bugs fixed:* * Connection string parsing for DSN-less connections could fail to identify some parameters. (Bug #25316) * Updates of `MEMO' or *Note `TEXT': blob. columns from within Microsoft Access would fail. (Bug #25263) * Transaction support has been added and tested. (Bug #25045) * Internal function, `my_setpos_delete_ignore()' could cause a crash. (Bug #22796) * Fixed occasional mis-handling of the `SQL_NUMERIC_C' type. * Fixed the binding of certain integer types.  File: manual.info, Node: connector-odbc-news-5-0-10, Next: connector-odbc-news-5-0-9, Prev: connector-odbc-news-5-0-11, Up: connector-odbc-news D.3.13 Changes in MySQL Connector/ODBC 5.0.10 (14 December 2006) ---------------------------------------------------------------- Connector/ODBC 5.0.10 is the sixth BETA release. *Functionality added or changed:* * Significant performance improvement when retrieving large text fields in pieces using `SQLGetData()' with a buffer smaller than the whole data. Mainly used in Access when fetching very large text fields. (Bug #24876) * Added initial unicode support in data and metadata. (Bug #24837) * Added initial support for removing braces when calling stored procedures and retrieving result sets from procedure calls. (Bug #24485) * Added loose handling of retrieving some diagnostic data. (Bug #15782) * Added wide-string type info for `SQLGetTypeInfo()'. *Bugs fixed:* * Editing DSN no longer crashes ODBC data source administrator. (Bug #24675) * String query parameters are new escaped correctly. (Bug #19078)  File: manual.info, Node: connector-odbc-news-5-0-9, Next: connector-odbc-news-5-0-8, Prev: connector-odbc-news-5-0-10, Up: connector-odbc-news D.3.14 Changes in MySQL Connector/ODBC 5.0.9 (22 November 2006) --------------------------------------------------------------- Connector/ODBC 5.0.9 is the fifth BETA release. This is an implementation and testing release, and is not designed for use within a production environment. *Functionality added or changed:* * Added support for column binding as SQL_NUMERIC_STRUCT. * Added recognition of `SQL_C_SHORT' and `SQL_C_TINYINT' as C types. *Bugs fixed:* * Fixed wildcard handling of and listing of catalogs and tables in `SQLTables'. * Added limit of display size when requested using `SQLColAttribute'/`SQL_DESC_DISPLAY_SIZE'. * Fixed buffer length return for SQLDriverConnect. * ODBC v2 behavior in driver now supports ODBC v3 date/time types (since DriverManager maps them). * Catch use of `SQL_ATTR_PARAMSET_SIZE' and report error until we fully support. * Fixed statistics to fail if it couldn't be completed. * Corrected retrieval multiple field types bit and blob/text. * Fixed SQLGetData to clear the NULL indicator correctly during multiple calls.  File: manual.info, Node: connector-odbc-news-5-0-8, Next: connector-odbc-news-5-0-7, Prev: connector-odbc-news-5-0-9, Up: connector-odbc-news D.3.15 Changes in MySQL Connector/ODBC 5.0.8 (17 November 2006) --------------------------------------------------------------- Connector/ODBC 5.0.8 is the fourth BETA release. This is an implementation and testing release, and is not designed for use within a production environment. *Functionality added or changed:* * Also made `SQL_DESC_NAME' only fill in the name if there was a data pointer given, otherwise just the length. * Fixed display size to be length if max length isn't available. * Made distinction between *Note `CHAR': char./*Note `BINARY': binary-varbinary. (and VAR versions). * Wildcards now support escaped chars and underscore matching (needed to link tables with underscores in access). *Bugs fixed:* * Fixed binding using `SQL_C_LONG'. * Fixed using wrong pointer for `SQL_MAX_DRIVER_CONNECTIONS' in `SQLGetInfo'. * Set default return to `SQL_SUCCESS' if nothing is done for `SQLSpecialColumns'. * Fixed MDiagnostic to use correct v2/v3 error codes. * Allow SQLDescribeCol to be called to retrieve the length of the column name, but not the name itself. * Length now used when handling bind parameter (needed in particular for `SQL_WCHAR') - this enables updating char data in MS Access. * Updated retrieval of descriptor fields to use the right pointer types. * Fixed handling of numeric pointers in SQLColAttribute. * Fixed type returned for `MYSQL_TYPE_LONG' to `SQL_INTEGER' instead of `SQL_TINYINT'. * Fix size return from `SQLDescribeCol'. * Fixed string length to chars, not bytes, returned by SQLGetDiagRec.  File: manual.info, Node: connector-odbc-news-5-0-7, Next: connector-odbc-news-5-0-6, Prev: connector-odbc-news-5-0-8, Up: connector-odbc-news D.3.16 Changes in MySQL Connector/ODBC 5.0.7 (08 November 2006) --------------------------------------------------------------- Connector/ODBC 5.0.7 is the third BETA release. This is an implementation and testing release, and is not designed for use within a production environment. *Functionality added or changed:* * Added support for `SQLStatistics' to `MYODBCShell'. * Improved trace/log. *Bugs fixed:* * SQLBindParameter now handles `SQL_C_DEFAULT'. * Corrected incorrect column index within `SQLStatistics'. Many more tables can now be linked into MS Access. * Fixed `SQLDescribeCol' returning column name length in bytes rather than chars.  File: manual.info, Node: connector-odbc-news-5-0-6, Next: connector-odbc-news-5-0-5, Prev: connector-odbc-news-5-0-7, Up: connector-odbc-news D.3.17 Changes in MySQL Connector/ODBC 5.0.6 (03 November 2006) --------------------------------------------------------------- Connector/ODBC 5.0.6 is the second BETA release. This is an implementation and testing release, and is not designed for use within a production environment. *Features, limitations, and notes on this release* * MySQL Connector/ODBC supports both `User' and `System' DSNs. * Installation is provided in the form of a standard Microsoft System Installer (MSI). * You no longer have to have MySQL Connector/ODBC 3.51 installed before installing this version. *Bugs fixed:* * You no longer have to have MySQL Connector/ODBC 3.51 installed before installing this version. * MySQL Connector/ODBC supports both `User' and `System' DSNs. * Installation is provided in the form of a standard Microsoft System Installer (MSI).  File: manual.info, Node: connector-odbc-news-5-0-5, Next: connector-odbc-news-5-0-3, Prev: connector-odbc-news-5-0-6, Up: connector-odbc-news D.3.18 Changes in MySQL Connector/ODBC 5.0.5 (17 October 2006) -------------------------------------------------------------- Connector/ODBC 5.0.5 is the first BETA release. This is an implementation and testing release, and is not designed for use within a production environment. You no longer have to have Connector/ODBC 3.51 installed before installing this version. *Bugs fixed:* * You no longer have to have MySQL Connector/ODBC 3.51 installed before installing this version.  File: manual.info, Node: connector-odbc-news-5-0-3, Next: connector-odbc-news-5-0-2, Prev: connector-odbc-news-5-0-5, Up: connector-odbc-news D.3.19 Changes in Connector/ODBC 5.0.3 (Connector/ODBC 5.0 Alpha 3) (20 June 2006) ---------------------------------------------------------------------------------- This is an implementation and testing release, and is not designed for use within a production environment. Features, limitations and notes on this release: * The following ODBC API functions have been added in this release: * `SQLBindParameter' * `SQLBindCol'  File: manual.info, Node: connector-odbc-news-5-0-2, Next: connector-odbc-news-5-0-1, Prev: connector-odbc-news-5-0-3, Up: connector-odbc-news D.3.20 Changes in Connector/ODBC 5.0.2 (Never released) ------------------------------------------------------- Connector/ODBC 5.0.2 was an internal implementation and testing release.  File: manual.info, Node: connector-odbc-news-5-0-1, Next: connector-odbc-news-3-51-28, Prev: connector-odbc-news-5-0-2, Up: connector-odbc-news D.3.21 Changes in Connector/ODBC 5.0.1 (Connector/ODBC 5.0 Alpha 2) (05 June 2006) ---------------------------------------------------------------------------------- Features, limitations and notes on this release: * Connector/ODBC 5.0 is Unicode aware. * Connector/ODBC is currently limited to basic applications. ADO applications and Microsoft Office are not supported. * Connector/ODBC must be used with a Driver Manager. * The following ODBC API functions are implemented: * `SQLAllocHandle' * `SQLCloseCursor' * `SQLColAttribute' * `SQLColumns' * `SQLConnect' * `SQLCopyDesc' * `SQLDisconnect' * `SQLExecDirect' * `SQLExecute' * `SQLFetch' * `SQLFreeHandle' * `SQLFreeStmt' * `SQLGetConnectAttr' * `SQLGetData' * `SQLGetDescField' * `SQLGetDescRec' * `SQLGetDiagField' * `SQLGetDiagRec' * `SQLGetEnvAttr' * `SQLGetFunctions' * `SQLGetStmtAttr' * `SQLGetTypeInfo' * `SQLNumResultCols' * `SQLPrepare' * `SQLRowcount' * `SQLTables' The following ODBC API function are implemented, but not yet support all the available attributes/options: * `SQLSetConnectAttr' * `SQLSetDescField' * `SQLSetDescRec' * `SQLSetEnvAttr' * `SQLSetStmtAttr'  File: manual.info, Node: connector-odbc-news-3-51-28, Next: connector-odbc-news-3-51-27, Prev: connector-odbc-news-5-0-1, Up: connector-odbc-news D.3.22 Changes in MySQL Connector/ODBC 3.51.28 (09 February 2011) ----------------------------------------------------------------- *Bugs fixed:* * `SQLColAttribute(...SQL_DESC_CASE_SENSITIVE...)' returned `SQL_FALSE' for binary types and `SQL_TRUE' for the rest. It should have returned `SQL_TRUE' for binary types, and `SQL_FALSE' for the rest. (Bug #54212) * `SQLColAttribute' for `SQL_DESC_OCTET_LENGTH' returned length including terminating null byte. It should not have included the null byte. (Bug #54206) * When executing the `SQLProcedureColumns()' ODBC function, the driver reported the following error: MySQL server does not provide the requested information (Bug #50400) * If `NO_BACKSLASH_ESCAPES' mode was used on a server, escaping binary data led to server query parsing errors. (Bug #49029) * Inserting a new record using `SQLSetPos' did not correspond to the database name specified in the `SELECT' statement when querying tables from databases other than the current one. `SQLSetPos' attempted to do the `INSERT' in the current database, but finished with a `SQL_ERROR' result and `Table does not exist' message from MySQL Server. (Bug #41946) * When using MySQL Connector/ODBC to fetch data, if a `net_write_timeout' condition occurred, the operation returned the standard "end of data" status, rather than an error. (Bug #39878) * No result record was returned for `SQLGetTypeInfo' for the `TIMESTAMP' data type. An application would receive the result `return code 100 (SQL_NO_DATA_FOUND)'. (Bug #30626) * Microsoft Access was not able to read `BIGINT' values properly from a table with just two columns of type `BIGINT' and `VARCHAR'. `#DELETE' appeared instead of the correct values. (Bug #17679)  File: manual.info, Node: connector-odbc-news-3-51-27, Next: connector-odbc-news-3-51-26, Prev: connector-odbc-news-3-51-28, Up: connector-odbc-news D.3.23 Changes in MySQL Connector/ODBC 3.51.27 (20 November 2008) ----------------------------------------------------------------- *Bugs fixed:* * The client program hung when the network connection to the server was interrupted. (Bug #40407) * The connection string option `Enable Auto-reconnect' did not work. When the connection failed, it could not be restored, and the errors generated were the same as if the option had not been selected. (Bug #37179) * It was not possible to use MySQL Connector/ODBC to connect to a server using SSL. The following error was generated: Runtime error '-2147467259 (80004005)': [MySQL][ODBC 3.51 Driver]SSL connection error. (Bug #29955)  File: manual.info, Node: connector-odbc-news-3-51-26, Next: connector-odbc-news-3-51-25, Prev: connector-odbc-news-3-51-27, Up: connector-odbc-news D.3.24 Changes in MySQL Connector/ODBC 3.51.26 (07 July 2008) ------------------------------------------------------------- *Functionality added or changed:* * There is a new connection option, `FLAG_NO_BINARY_RESULT'. When set this option disables charset 63 for columns with an empty `org_table'. (Bug #29402) *Bugs fixed:* * When an ADOConnection is created and attempts to open a schema with ADOConnection.OpenSchema an access violation occurs in `myodbc3.dll'. (Bug #30770) * When *Note `SHOW CREATE TABLE': show-create-table. was invoked and then the field values read, the result was truncated and unusable if the table had many rows and indexes. (Bug #24131)  File: manual.info, Node: connector-odbc-news-3-51-25, Next: connector-odbc-news-3-51-24, Prev: connector-odbc-news-3-51-26, Up: connector-odbc-news D.3.25 Changes in MySQL Connector/ODBC 3.51.25 (11 April 2008) -------------------------------------------------------------- *Bugs fixed:* * The `SQLColAttribute()' function returned `SQL_TRUE' when querying the `SQL_DESC_FIXED_PREC_SCALE (SQL_COLUMN_MONEY)' attribute of a *Note `DECIMAL': numeric-types. column. Previously, the correct value of `SQL_FALSE' was returned; this is now again the case. (Bug #35581) * The driver crashes ODBC Administrator on attempting to add a new DSN. (Bug #32057) * When accessing column data, `FLAG_COLUMN_SIZE_S32' did not limit the octet length or display size reported for fields, causing problems with Microsoft Visual FoxPro. The list of ODBC functions that could have caused failures in Microsoft software when retrieving the length of *Note `LONGBLOB': blob. or *Note `LONGTEXT': blob. columns includes: * `SQLColumns' * `SQLColAttribute' * `SQLColAttributes' * `SQLDescribeCol' * `SQLSpecialColumns' (theoretically can have the same problem) (Bug #12805, Bug #30890)  File: manual.info, Node: connector-odbc-news-3-51-24, Next: connector-odbc-news-3-51-23, Prev: connector-odbc-news-3-51-25, Up: connector-odbc-news D.3.26 Changes in MySQL Connector/ODBC 3.51.24 (14 March 2008) -------------------------------------------------------------- *Bugs fixed:* * *Security Enhancement*: Accessing a parameter with the type of `SQL_C_CHAR', but with a numeric type and a length of zero, the parameter marker would get stropped from the query. In addition, an SQL injection was possible if the parameter value had a nonzero length and was not numeric, the text would be inserted verbatim. (Bug #34575) * *Important Change*: In previous versions, the SSL certificate would automatically be verified when used as part of the MySQL Connector/ODBC connection. The default mode is now to ignore the verificate of certificates. To enforce verification of the SSL certificate during connection, use the `SSLVERIFY' DSN parameter, setting the value to 1. (Bug #29955, Bug #34648) * When using ADO, the count of parameters in a query would always return zero. (Bug #33298) * Using tables with a single quote or other nonstandard characters in the table or column names through ODBC would fail. (Bug #32989) * When using Crystal Reports, table and column names would be truncated to 21 characters, and truncated columns in tables where the truncated name was the duplicated would lead to only a single column being displayed. (Bug #32864) * `SQLExtendedFetch()' and `SQLFetchScroll()' ignored the rowset size if the `Don't cache result' DSN option was set. (Bug #32420) * When using the ODBC `SQL_TXN_READ_COMMITTED' option, 'dirty' records would be read from tables as if the option had not been applied. (Bug #31959) * When creating a System DSN using the ODBC Administrator on Mac OS X, a User DSN would be created instead. The root cause is a problem with the iODBC driver manager used on Mac OS X. The fix works around this issue. *Note*: ODBC Administrator may still be unable to register a System DSN unless the `/Library/ODBC/odbc.ini' file has the correct permissions. You should ensure that the file is writable by the `admin' group. (Bug #31495) * Calling `SQLFetch' or `SQLFetchScroll' would return negative data lengths when using `SQL_C_WCHAR'. (Bug #31220) * `SQLSetParam()' caused memory allocation errors due to driver manager's mapping of deprecated functions (buffer length -1). (Bug #29871) * Static cursor was unable to be used through ADO when dynamic cursors were enabled. (Bug #27351) * Using `connection.Execute' to create a record set based on a table without declaring the cmd option as `adCmdTable' will fail when communicating with versions of MySQL 5.0.37 and higher. The issue is related to the way that `SQLSTATE' is returned when ADO tries to confirm the existence of the target object. (Bug #27158) * Updating a `RecordSet' when the query involves a *Note `BLOB': blob. field would fail. (Bug #19065) * With some connections to MySQL databases using MySQL Connector/ODBC, the connection would mistakenly report 'user cancelled' for accesses to the database information. (Bug #16653)  File: manual.info, Node: connector-odbc-news-3-51-23, Next: connector-odbc-news-3-51-22, Prev: connector-odbc-news-3-51-24, Up: connector-odbc-news D.3.27 Changes in MySQL Connector/ODBC 3.51.23 (09 January 2008) ---------------------------------------------------------------- *Platform specific notes:* * The HP-UX 11.23 IA64 binary package does not include the GUI bits because of problems building Qt on that platform. * There is no binary package for Mac OS X on 64-bit PowerPC because Apple does not currently provide a 64-bit PowerPC version of iODBC. * There are no installer packages for Microsoft Windows x64 Edition. *Bugs fixed:* * MySQL Connector/ODBC would incorrectly return `SQL_SUCCESS' when checking for distributed transaction support. (Bug #32727) * When using unixODBC or directly linked applications where the thread level is set to less than 3 (within `odbcinst.ini'), a thread synchronization issue would lead to an application crash. This was because `SQLAllocStmt()' and `SQLFreeStmt()' did not synchronize access to the list of statements associated with a connection. (Bug #32587) * Cleaning up environment handles in multithread environments could result in a five (or more) second delay. (Bug #32366) * Renaming an existing DSN entry would create a new entry with the new name without deleting the old entry. (Bug #31165) * Setting the default database using the `DefaultDatabase' property of an ADO `Connection' object would fail with the error `Provider does not support this property'. The `SQLGetInfo()' returned the wrong value for `SQL_DATABASE_NAME' when no database was selected. (Bug #3780)  File: manual.info, Node: connector-odbc-news-3-51-22, Next: connector-odbc-news-3-51-21, Prev: connector-odbc-news-3-51-23, Up: connector-odbc-news D.3.28 Changes in MySQL Connector/ODBC 3.51.22 (13 November 2007) ----------------------------------------------------------------- *Functionality added or changed:* * The workaround for this bug was removed due to the fixes in MySQL Server 5.0.48 and 5.1.21. This regression was introduced by Bug #10491. *Bugs fixed:* * The `English' locale would be used when formatting floating point values. The `C' locale is now used for these values. (Bug #32294) * When accessing information about supported operations, the driver would return incorrect information about the support for *Note `UNION': union. (Bug #32253) * Unsigned integer values greater than the maximum value of a signed integer would be handled incorrectly. (Bug #32171) * The wrong result was returned by `SQLGetData()' when the data was an empty string and a zero-sized buffer was specified. (Bug #30958) * Added the `FLAG_COLUMN_SIZE_S32' option to limit the reported column size to a signed 32-bit integer. This option is automatically enabled for ADO applications to provide a work around for a bug in ADO. (Bug #13776)  File: manual.info, Node: connector-odbc-news-3-51-21, Next: connector-odbc-news-3-51-20, Prev: connector-odbc-news-3-51-22, Up: connector-odbc-news D.3.29 Changes in MySQL Connector/ODBC 3.51.21 (08 October 2007) ---------------------------------------------------------------- *Bugs fixed:* * When using a rowset/cursor and add a new row with a number of fields, subsequent rows with fewer fields will include the original fields from the previous row in the final *Note `INSERT': insert. statement. (Bug #31246) * Uninitiated memory could be used when C/ODBC internally calls `SQLGetFunctions()'. (Bug #31055) * The wrong `SQL_DESC_LITERAL_PREFIX' would be returned for date/time types. (Bug #31009) * The wrong `COLUMN_SIZE' would be returned by `SQLGetTypeInfo' for the TIME columns (`SQL_TYPE_TIME'). (Bug #30939) * Clicking outside the character set selection box when configuring a new DSN could cause the wrong character set to be selected. (Bug #30568) * Not specifying a user in the DSN dialog would raise a warning even though the parameter is optional. (Bug #30499) * `SQLSetParam()' caused memory allocation errors due to driver manager's mapping of deprecated functions (buffer length -1). (Bug #29871) * When using ADO, a column marked as `AUTO_INCREMENT' could incorrectly report that the column permitted `NULL' values. This was dur to an issue with `NULLABLE' and `IS_NULLABLE' return values from the call to `SQLColumns()'. (Bug #26108) * MySQL Connector/ODBC would return the wrong the error code when the server disconnects the active connection because the configured `wait_timeout' has expired. Previously it would return `HY000'. MySQL Connector/ODBC now correctly returns an `SQLSTATE' of `08S01'. (Bug #3456)  File: manual.info, Node: connector-odbc-news-3-51-20, Next: connector-odbc-news-3-51-19, Prev: connector-odbc-news-3-51-21, Up: connector-odbc-news D.3.30 Changes in MySQL Connector/ODBC 3.51.20 (10 September 2007) ------------------------------------------------------------------ *Bugs fixed:* * Using `FLAG_NO_PROMPT' doesn't suppress the dialogs normally handled by `SQLDriverConnect'. (Bug #30840) * The specified length of the user name and authentication parameters to `SQLConnect()' were not being honored. (Bug #30774) * The wrong column size was returned for binary data. (Bug #30547) * `SQLGetData()' will now always return `SQL_NO_DATA_FOUND' on second call when no data left, even if requested size is 0. (Bug #30520) * `SQLGetConnectAttr()' did not reflect the connection state correctly. (Bug #14639) * Removed check box in setup dialog for `FLAG_FIELD_LENGTH' (identified as `Don't Optimize Column Width' within the GUI dialog), which was removed from the driver in 3.51.18.  File: manual.info, Node: connector-odbc-news-3-51-19, Next: connector-odbc-news-3-51-18, Prev: connector-odbc-news-3-51-20, Up: connector-odbc-news D.3.31 Changes in MySQL Connector/ODBC 3.51.19 (10 August 2007) --------------------------------------------------------------- Connector/ODBC 3.51.19 fixes a specific issue with the 3.51.18 release. For a list of changes in the 3.51.18 release, see *Note connector-odbc-news-3-51-18::. *Functionality added or changed:* * Because of Bug#10491 in the server, character string results were sometimes incorrectly identified as `SQL_VARBINARY'. Until this server bug is corrected, the driver will identify all variable-length strings as `SQL_VARCHAR'.  File: manual.info, Node: connector-odbc-news-3-51-18, Next: connector-odbc-news-3-51-17, Prev: connector-odbc-news-3-51-19, Up: connector-odbc-news D.3.32 Changes in MySQL Connector/ODBC 3.51.18 (08 August 2007) --------------------------------------------------------------- *Platform specific notes:* * The HP-UX 11.23 IA64 binary package does not include the GUI bits because of problems building Qt on that platform. * There is no binary package for Mac OS X on 64-bit PowerPC because Apple does not currently provide a 64-bit PowerPC version of iODBC. * Binary packages for Sun Solaris are now available as `PKG' packages. * Binary packages as disk images with installers are now available for Mac OS X. * A binary package without an installer is available for Microsoft Windows x64 Edition. There are no installer packages for Microsoft Windows x64 Edition. *Functionality added or changed:* * *Incompatible Change*: The `FLAG_DEBUG' option was removed. * When connecting to a specific database when using a DSN, the system tables from the `mysql' database are no longer also available. Previously, tables from the mysql database (catalog) were listed as `SYSTEM TABLES' by `SQLTables()' even when a different catalog was being queried. (Bug #28662) * Installed for Mac OS X has been re-instated. The installer registers the driver at a system (not user) level and makes it possible to create both user and system DSNs using the MySQL Connector/ODBC driver. The installer also fixes the situation where the necessary drivers would bge installed local to the user, not globally. (Bug #15326, Bug #10444) * MySQL Connector/ODBC now supports batched statements. To enable cached statement support, you must switch enable the batched statement option (`FLAG_MULTI_STATEMENTS', 67108864, or `Allow multiple statements' within a GUI configuration). Be aware that batched statements create an increased chance of SQL injection attacks and you must ensure that your application protects against this scenario. (Bug #7445) * The `SQL_ATTR_ROW_BIND_OFFSET_PTR' is now supported for row bind offsets. (Bug #6741) * The `TRACE' and `TRACEFILE' DSN options have been removed. Use the ODBC driver manager trace options instead. *Bugs fixed:* * When using a table with multiple *Note `TIMESTAMP': datetime. columns, the final *Note `TIMESTAMP': datetime. column within the table definition would not be updateable. Note that there is still a limitation in MySQL server regarding multiple *Note `TIMESTAMP': datetime. columns . (Bug#9927) (Bug #30081) * Fixed an issue where the `myodbc3i' would update the user ODBC configuration file (`~/Library/ODBC/odbcinst.ini') instead of the system `/Library/ODBC/odbcinst.ini'. This was caused because `myodbc3i' was not honoring the `s' and `u' modifiers for the `-d' command-line option. (Bug #29964) * Getting table metadata (through the `SQLColumns()' would fail, returning a bad table definition to calling applications. (Bug #29888) * *Note `DATETIME': datetime. column types would return `FALSE' in place of `SQL_SUCCESS' when requesting the column type information. (Bug #28657) * The `SQL_COLUMN_TYPE', `SQL_COLUMN_DISPLAY' and `SQL_COLUMN_PRECISION' values would be returned incorrectly by `SQLColumns()', `SQLDescribeCol()' and `SQLColAttribute()' when accessing character columns, especially those generated through `concat()'. The lengths returned should now conform to the ODBC specification. The `FLAG_FIELD_LENGTH' option no longer has any affect on the results returned. (Bug #27862) * Obtaining the length of a column when using a character set for the connection of `utf8' would result in the length being returned incorrectly. (Bug #19345) * The `SQLColumns()' function could return incorrect information about *Note `TIMESTAMP': datetime. columns, indicating that the field was not nullable. (Bug #14414) * The `SQLColumns()' function could return incorrect information about `AUTO_INCREMENT' columns, indicating that the field was not nullable. (Bug #14407) * A binary package without an installer is available for Microsoft Windows x64 Edition. There are no installer packages for Microsoft Windows x64 Edition. * There is no binary package for Mac OS X on 64-bit PowerPC because Apple does not currently provide a 64-bit PowerPC version of iODBC. * `BIT(n)' columns are now treated as `SQL_BIT' data where `n = 1' and binary data where `n > 1'. * The wrong value from `SQL_DESC_LITERAL_SUFFIX' was returned for binary fields. * The `SQL_DATETIME_SUB' column in SQLColumns() was not correctly set for date and time types. * The value for `SQL_DESC_FIXED_PREC_SCALE' was not returned correctly for values in MySQL 5.0 and later. * The wrong value for `SQL_DESC_TYPE' was returned for date and time types. * `SQLConnect()' and `SQLDriverConnect()' were rewritten to eliminate duplicate code and ensure all options were supported using both connection methods. `SQLDriverConnect()' now only requires the setup library to be present when the call requires it. * The HP-UX 11.23 IA64 binary package does not include the GUI bits because of problems building Qt on that platform. * Binary packages as disk images with installers are now available for Mac OS X. * Binary packages for Sun Solaris are now available as `PKG' packages. * The wrong value for `DECIMAL_DIGITS' in `SQLColumns()' was reported for *Note `FLOAT': numeric-types. and *Note `DOUBLE': numeric-types. fields, as well as the wrong value for the scale parameter to `SQLDescribeCol()', and the `SQL_DESC_SCALE' attribute from `SQLColAttribute()'. * The `SQL_DATA_TYPE' column in `SQLColumns()' results did not report the correct value for date and time types.  File: manual.info, Node: connector-odbc-news-3-51-17, Next: connector-odbc-news-3-51-16, Prev: connector-odbc-news-3-51-18, Up: connector-odbc-news D.3.33 Changes in MySQL Connector/ODBC 3.51.17 (14 July 2007) ------------------------------------------------------------- *Platform specific notes:* * The HP-UX 11.23 IA64 binary package does not include the GUI bits because of problems building Qt on that platform. * There is no binary package for Mac OS X on 64-bit PowerPC because Apple does not currently provide a 64-bit PowerPC version of iODBC. * Binary packages for Sun Solaris are now available as `PKG' packages. * Binary packages as disk images with installers are now available for Mac OS X. * A binary package without an installer is available for Microsoft Windows x64 Edition. There are no installer packages for Microsoft Windows x64 Edition. *Functionality added or changed:* * It is now possible to specify a different character set as part of the DSN or connection string. This must be used instead of the `SET NAMES' statement. You can also configure the character set value from the GUI configuration. (Bug #9498, Bug #6667) * Fixed calling convention ptr and wrong free in `myodbc3i', and fixed the null terminating (was only one, not two) when writing DSN to string. * Dis-allow NULL ptr for null indicator when calling SQLGetData() if value is null. Now returns SQL_ERROR w/state 22002. * The setup library has been split into its own RPM package, to enable installing the driver itself with no GUI dependencies. *Bugs fixed:* * `myodbc3i' did not correctly format driver info, which could cause the installation to fail. (Bug #29709) * MySQL Connector/ODBC crashed with Crystal Reports due to a rproblem with `SQLProcedures()'. (Bug #28316) * Fixed a problem where the GUI would crash when configuring or removing a System or User DSN. (Bug #27315) * Fixed error handling of out-of-memory and bad connections in catalog functions. This might raise errors in code paths that had ignored them in the past. (Bug #26934) * For a stored procedure that returns multiple result sets, MySQL Connector/ODBC returned only the first result set. (Bug #16817) * Calling `SQLGetDiagField' with `RecNumber 0, DiagIdentifier NOT 0' returned `SQL_ERROR', preventing access to diagnostic header fields. (Bug #16224) * Added a new DSN option (`FLAG_ZERO_DATE_TO_MIN') to retrieve `XXXX-00-00' dates as the minimum permitted ODBC date (`XXXX-01-01'). Added another option (`FLAG_MIN_DATE_TO_ZERO') to mirror this but for bound parameters. `FLAG_MIN_DATE_TO_ZERO' only changes `0000-01-01' to `0000-00-00'. (Bug #13766) * If there was more than one unique key on a table, the correct fields were not used in handling `SQLSetPos()'. (Bug #10563) * When inserting a large *Note `BLOB': blob. field, MySQL Connector/ODBC would crash due to a memory allocation error. (Bug #10562) * The driver was using `mysql_odbc_escape_string()', which does not handle the `NO_BACKSLASH_ESCAPES' SQL mode. Now it uses *Note `mysql_real_escape_string()': mysql-real-escape-string, which does. (Bug #9498) * `SQLColumns()' did not handle many of its parameters correctly, which could lead to incorrect results. The table name argument was not handled as a pattern value, and most arguments were not escaped correctly when they contained nonalphanumeric characters. (Bug #8860) * There are no binary packages for Microsoft Windows x64 Edition. * There is no binary package for Mac OS X on 64-bit PowerPC because Apple does not currently provide a 64-bit PowerPC version of iODBC. * Correctly return error if `SQLBindCol' is called with an invalid column. * Fixed possible crash if `SQLBindCol()' was not called before `SQLSetPos()'. * The Mac OS X binary packages are only provided as tarballs, there is no installer. * The binary packages for Sun Solaris are only provided as tarballs, not the PKG format. * The HP-UX 11.23 IA64 binary package does not include the GUI bits because of problems building Qt on that platform.  File: manual.info, Node: connector-odbc-news-3-51-16, Next: connector-odbc-news-3-51-15, Prev: connector-odbc-news-3-51-17, Up: connector-odbc-news D.3.34 Changes in MySQL Connector/ODBC 3.51.16 (14 June 2007) ------------------------------------------------------------- *Functionality added or changed:* * MySQL Connector/ODBC now supports using SSL for communication. This is not yet exposed in the setup GUI, but must be enabled through configuration files or the DSN. (Bug #12918) *Bugs fixed:* * Calls to SQLNativeSql() could cause stack corruption due to an incorrect pointer cast. (Bug #28758) * Using cursors on results sets with multi-column keys could select the wrong value. (Bug #28255) * `SQLForeignKeys' does not escape `_' and `%' in the table name arguments. (Bug #27723) * When using stored procedures, making a *Note `SELECT': select. or second stored procedure call after an initial stored procedure call, the second statement will fail. (Bug #27544) * SQLTables() did not distinguish tables from views. (Bug #23031) * Data in *Note `TEXT': blob. columns would fail to be read correctly. (Bug #16917) * Specifying strings as parameters using the `adBSTR' or `adVarWChar' types, (`SQL_WVARCHAR' and `SQL_WLONGVARCHAR') would be incorrectly quoted. (Bug #16235) * SQL_WVARCHAR and SQL_WLONGVARCHAR parameters were not properly quoted and escaped. (Bug #16235) * Using `BETWEEN' with date values, the wrong results could be returned. (Bug #15773) * When using the `Don't Cache Results' (option value `1048576') with Microsoft Access, the connection will fail using DAO/VisualBasic. (Bug #4657) * Return values from `SQLTables()' may be truncated. (Bugs #22797)  File: manual.info, Node: connector-odbc-news-3-51-15, Next: connector-odbc-news-3-51-14, Prev: connector-odbc-news-3-51-16, Up: connector-odbc-news D.3.35 Changes in MySQL Connector/ODBC 3.51.15 (07 May 2007) ------------------------------------------------------------ *Bugs fixed:* * MySQL Connector/ODBC would incorrectly claim to support `SQLProcedureColumns' (by returning true when queried about `SQLPROCEDURECOLUMNS' with `SQLGetFunctions'), but this functionality is not supported. (Bug #27591) * An incorrect transaction isolation level may not be returned when accessing the connection attributes. (Bug #27589) * Adding a new DSN with the `myodbc3i' utility under AIX would fail. (Bug #27220) * When inserting data using bulk statements (through `SQLBulkOperations'), the indicators for all rows within the insert would not updated correctly. (Bug #24306) * Using `SQLProcedures' does not return the database name within the returned resultset. (Bug #23033) * The `SQLTransact()' function did not support an empty connection handle. (Bug #21588) * Using `SQLDriverConnect' instead of `SQLConnect' could cause later operations to fail. (Bug #7912) * When using blobs and parameter replacement in a statement with `WHERE CURSOR OF', the SQL is truncated. (Bug #5853) * MySQL Connector/ODBC would return too many foreign key results when accessing tables with similar names. (Bug #4518)  File: manual.info, Node: connector-odbc-news-3-51-14, Next: connector-odbc-news-3-51-13, Prev: connector-odbc-news-3-51-15, Up: connector-odbc-news D.3.36 Changes in MySQL Connector/ODBC 3.51.14 (08 March 2007) -------------------------------------------------------------- *Functionality added or changed:* * Use of `SQL_ATTR_CONNECTION_TIMEOUT' on the server has now been disabled. If you attempt to set this attribute on your connection the `SQL_SUCCESS_WITH_INFO' will be returned, with an error number/string of `HYC00: Optional feature not supported'. (Bug #19823) * Added auto is null option to MySQL Connector/ODBC option parameters. (Bug #10910) * Added auto-reconnect option to MySQL Connector/ODBC option parameters. * Added support for the `HENV' handlers in `SQLEndTran()'. *Bugs fixed:* * On 64-bit systems, some types would be incorrectly returned. (Bug #26024) * When retrieving *Note `TIME': time. columns, C/ODBC would incorrectly interpret the type of the string and could interpret it as a *Note `DATE': datetime. type instead. (Bug #25846) * MySQL Connector/ODBC may insert the wrong parameter values when using prepared statements under 64-bit Linux. (Bug #22446) * Using MySQL Connector/ODBC, with `SQLBindCol' and binding the length to the return value from `SQL_LEN_DATA_AT_EXEC' fails with a memory allocation error. (Bug #20547) * Using `DataAdapter', MySQL Connector/ODBC may continually consume memory when reading the same records within a loop (Windows Server 2003 SP1/SP2 only). (Bug #20459) * When retrieving data from columns that have been compressed using `COMPRESS()', the retrieved data would be truncated to 8KB. (Bug #20208) * The ODBC driver name and version number were incorrectly reported by the driver. (Bug #19740) * A string format exception would be raised when using iODBC, MySQL Connector/ODBC and the embedded MySQL server. (Bug #16535) * The `SQLDriverConnect()' ODBC method did not work with recent MySQL Connector/ODBC releases. (Bug #12393)  File: manual.info, Node: connector-odbc-news-3-51-13, Next: connector-odbc-news-3-51-12, Prev: connector-odbc-news-3-51-14, Up: connector-odbc-news D.3.37 Changes in MySQL Connector/ODBC 3.51.13 (Never released) --------------------------------------------------------------- Connector/ODBC 3.51.13 was an internal implementation and testing release. This section has no changelog entries.  File: manual.info, Node: connector-odbc-news-3-51-12, Next: connector-odbc-news-3-51-11, Prev: connector-odbc-news-3-51-13, Up: connector-odbc-news D.3.38 Changes in MySQL Connector/ODBC 3.51.12 (11 February 2005) ----------------------------------------------------------------- *Functionality added or changed:* * N/A *Bugs fixed:* * Using stored procedures with ADO, where the `CommandType' has been set correctly to `adCmdStoredProc', calls to stored procedures would fail. (Bug #15635) * File DSNs could not be saved. (Bug #12019) * `SQLColumns()' returned no information for tables that had a column named using a reserved word. (Bug #9539)  File: manual.info, Node: connector-odbc-news-3-51-11, Prev: connector-odbc-news-3-51-12, Up: connector-odbc-news D.3.39 Changes in MySQL Connector/ODBC 3.51.11 (28 January 2005) ---------------------------------------------------------------- *Bugs fixed:* * `mysql_list_dbcolumns()' and `insert_fields()' were retrieving all rows from a table. Fixed the queries generated by these functions to return no rows. (Bug #8198) * `SQLGetTypoInfo()' returned `tinyblob' for `SQL_VARBINARY' and nothing for `SQL_BINARY'. Fixed to return `varbinary' for `SQL_VARBINARY', `binary' for `SQL_BINARY', and `longblob' for `SQL_LONGVARBINARY'. (Bug #8138)  File: manual.info, Node: connector-net-news, Next: vstudio-plugin-news, Prev: connector-odbc-news, Up: news D.4 MySQL Connector/NET Change History ====================================== * Menu: * changes-6.4.x:: Changes in MySQL Connector/NET Version 6.4.x * changes-6.3.x:: Changes in MySQL Connector/NET Version 6.3.x * changes-6.2.x:: Changes in MySQL Connector/NET Version 6.2.x * changes-6.1.x:: Changes in MySQL Connector/NET Version 6.1.x * changes-6.0.x:: Changes in MySQL Connector/NET Version 6.0.x * changes-5.3.x:: Changes in MySQL Connector/NET Version 5.3.x * changes-5.2.x:: Changes in MySQL Connector/NET Version 5.2.x * changes-5.1.x:: Changes in MySQL Connector/NET Version 5.1.x * changes-5.0.x:: Changes in MySQL Connector/NET Version 5.0.x * changes-1.0.x:: Changes in MySQL Connector/NET Version 1.0.x * connector-net-0-9-0:: Changes in MySQL Connector/NET Version 0.9.0 (30 August 2004) * connector-net-news-0-76:: Changes in MySQL Connector/NET Version 0.76 * connector-net-news-0-75:: Changes in MySQL Connector/NET Version 0.75 * connector-net-0-74:: Changes in MySQL Connector/NET Version 0.74 * connector-net-news-0-71:: Changes in MySQL Connector/NET Version 0.71 * connector-net-news-0-70:: Changes in MySQL Connector/NET Version 0.70 * connector-net-news-0-68:: Changes in MySQL Connector/NET Version 0.68 * connector-net-news-0-65:: Changes in MySQL Connector/NET Version 0.65 * connector-net-news-0-60:: Changes in MySQL Connector/NET Version 0.60 * connector-net-news-0-50:: Changes in MySQL Connector/NET Version 0.50  File: manual.info, Node: changes-6.4.x, Next: changes-6.3.x, Prev: connector-net-news, Up: connector-net-news D.4.1 Changes in MySQL Connector/NET Version 6.4.x -------------------------------------------------- * Menu: * connector-net-news-6-4-1:: Changes in MySQL Connector/NET 6.4.1 (Not yet released Alpha)  File: manual.info, Node: connector-net-news-6-4-1, Prev: changes-6.4.x, Up: changes-6.4.x D.4.1.1 Changes in MySQL Connector/NET 6.4.1 (Not yet released Alpha) ..................................................................... First alpha. *Functionality added or changed:* * Calling a stored procedure with output parameters caused a marked performance decrease. (Bug #60366, Bug #12425959) * Changed how the procedure schema collection is retrieved. If the connection string contains ``use procedure bodies=true'' then a *Note `SELECT': select. is performed on the `mysql.proc' table directly, as this is up to 50 times faster than the current Information Schema implementation. If the connection string contains ``use procedure bodies=false'', then the Information Schema collection is queried. (Bug #36694)  File: manual.info, Node: changes-6.3.x, Next: changes-6.2.x, Prev: changes-6.4.x, Up: connector-net-news D.4.2 Changes in MySQL Connector/NET Version 6.3.x -------------------------------------------------- * Menu: * connector-net-news-6-3-7:: Changes in MySQL Connector/NET 6.3.7 (Not yet released GA) * connector-net-news-6-3-6:: Changes in MySQL Connector/NET 6.3.6 (03 January 2011 GA) * connector-net-news-6-3-5:: Changes in MySQL Connector/NET 6.3.5 (12 October 2010 GA) * connector-net-news-6-3-4:: Changes in MySQL Connector/NET 6.3.4 (01 September 2010 GA) * connector-net-news-6-3-3:: Changes in MySQL Connector/NET 6.3.3 (27 July 2010 beta) * connector-net-news-6-3-2:: Changes in MySQL Connector/NET 6.3.2 (24 May 2010 beta) * connector-net-news-6-3-1:: Changes in MySQL Connector/NET 6.3.1 (02 March 2010 alpha) * connector-net-news-6-3-0:: Changes in MySQL Connector/NET 6.3.0 (16 February 2010 alpha)  File: manual.info, Node: connector-net-news-6-3-7, Next: connector-net-news-6-3-6, Prev: changes-6.3.x, Up: changes-6.3.x D.4.2.1 Changes in MySQL Connector/NET 6.3.7 (Not yet released GA) .................................................................. Fourth GA release. Fixes bugs since 6.3.6. *Functionality added or changed:* * Calling a stored procedure with output parameters caused a marked performance decrease. (Bug #60366, Bug #12425959) *Bugs fixed:* * MySQL Connector/NET 6.3.6 did not work with Visual Studio 2010. (Bug #60723, Bug #12394470) * `MysqlDataReader.GetSchemaTable' returned incorrect values and types. (Bug #59989, Bug #11776346) * All queries other than `INSERT' were executed individually instead of as a batch even though batching was enabled for the connection. (Bug #59616, Bug #11850286) * MySQL Connector/NET generated an exception when executing a query consisting of ';', for example: mycmd(";",mycon) mycmd.executenonquery() The exception generated was: System.IndexOutOfRangeException: Index was outside the bounds of the array. at MySql.Data.MySqlClient.MySqlCommand.TrimSemicolons(String sql) at MySql.Data.MySqlClient.MySqlCommand.ExecuteReader(CommandBehavior behavior) at MySql.Data.MySqlClient.MySqlCommand.ExecuteReader() at MySql.Data.MySqlClient.MySqlCommand.ExecuteNonQuery() (Bug #59537, Bug #11766433) * Setting `Membership.ApplicationName' had no effect. (Bug #59438, Bug #11770465) * A `NullReferenceException' was thrown on disposal of a `TransactionScope' object. (Bug #59346, Bug #11766272) * The setup wizard failed with the error `Setup Wizard ended prematurely because of an error'. This was because it assumed .NET Framework version 4.0 was located on the C: drive, when it was actually located on the E: drive. (Bug #59301)  File: manual.info, Node: connector-net-news-6-3-6, Next: connector-net-news-6-3-5, Prev: connector-net-news-6-3-7, Up: changes-6.3.x D.4.2.2 Changes in MySQL Connector/NET 6.3.6 (03 January 2011 GA) ................................................................. Third GA release. Fixes bugs since 6.3.5. *Functionality added or changed:* * Changed how the procedure schema collection is retrieved. If the connection string contains ``use procedure bodies=true'' then a *Note `SELECT': select. is performed on the `mysql.proc' table directly, as this is up to 50 times faster than the current Information Schema implementation. If the connection string contains ``use procedure bodies=false'', then the Information Schema collection is queried. (Bug #36694) *Bugs fixed:* * `MembershipProvider' did not generate hashes correctly if the algorithm was keyed. The Key of the algorithm should have been set if the `HashAlgorithm' was `KeyedHashAlgorithm'. (Bug #58906) * Code introduced to fix bug #54863 proved problematic on .NET version 3.5 and above. (Bug #58853) * The `MySqlTokenizer' contained unnecessary `Substring' and `Trim' calls: string token = sql.Substring(startIndex, stopIndex - startIndex).Trim(); The variable `token' was not used anywhere in the code. (Bug #58757) * `MySqlCommand.ExecuteReader(CommandBehavior)' threw a `NullReferenceException' when being called with `CommandBehavior.CloseConnection', if the SQL statement contained a syntax error, or contained invalid data such as an invalid column name. (Bug #58652) * `ReadFieldLength()' returned incorrect value for `BIGINT' autoincrement columns. (Bug #58373) * When attempting to create an ADO.NET Entity Data Model, MySQL connections were not available. (Bug #58278) * MySQL Connector/NET did not support the `utf8mb4' character set. When attempting to connect to `utf8mb4' tables or columns, an exception `KeyNotFoundException' was generated. (Bug #58244) * Installation of MySQL Connector/NET 6.3.5 failed. The error reported was: MySQL Connector Net 6.3.5 Setup Wizard ended prematurely because of an error. Your system has not been modified. (Bug #57654) * When the tracing driver was used and an SQL statement was longer than 300 characters, an ArgumentOutOfRangeExcpetion occurred if the statement also contained a quoted character, and the 300th character was in the middle of a quoted token. (Bug #57641) * Calling the `Read()' method on a `DataReader' obtained from `MySqlHelper.ExecuteReader' generated the following exception: Unhandled Exception: MySql.Data.MySqlClient.MySqlException: Invalid attempt to R ead when reader is closed. at MySql.Data.MySqlClient.MySqlDataReader.Read() at MySqlTest.MainClass.Main(String[] args) (Bug #57501) * Default values returned for text columns were not quoted. This meant that the `COLUMN_DEFAULT' field of the `GetSchema' columns collection did not return a valid SQL expression. (Bug #56509) * When using MySQL Connector/NET on Mono 2.8 using .NET 4.0, attempting to connect to a MySQL database generated the following exception: Unhandled Exception: System.MissingMethodException: Method not found: 'System.Data.Common.DbConnection.EnlistTransaction'. at (wrapper remoting-invoke-with-check) MySql.Data.MySqlClient.MySqlConnection:Open () (Bug #56509) * MySQL Connector/NET for .NET/Mono attempted to dynamically load the assembly `Mono.Posix.dll' when a Unix socket was used to connect to the server. This failed and the connector was not able to use a Unix socket unless the `Mono.Posix.dll' assembly was previously loaded by the program. (Bug #56410) * The ADO.NET Entity Data Model could not add stored procedures from MySQL Server 5.0.45 but worked fine using MySQL Server 5.1. (Bug #55349) * In the ADO.NET Entity Data Model Wizard, the time to update a model scaled abnormally as the number of entities increased. (Bug #48791, Bug #12596237)  File: manual.info, Node: connector-net-news-6-3-5, Next: connector-net-news-6-3-4, Prev: connector-net-news-6-3-6, Up: changes-6.3.x D.4.2.3 Changes in MySQL Connector/NET 6.3.5 (12 October 2010 GA) ................................................................. Second GA release. Fixes bugs since 6.3.4. *Bugs fixed:* * A typed dataset did not get the table name. (Bug #57894, Bug #11764989) * Setting `MySqlCommand.CommandTimeout' to 0 had no effect. It should have resulted in an infinite timeout. (Bug #57265) * When performing a row-by-row update, only the first row was updated and all other rows were ignored. (Bug #57092) * MySQL Connector/NET experienced two problems as follows: 1. A call to `System.Data.Objects.ObjectContext.DatabaseExists()' returned false, even if the database existed. 2. A call to `System.Data.Objects.ObjectContext.CreateDatabase()' created a database but with a name other than the one specified in the connection string. It then failed to use it when EDM objects were processed. (Bug #56859) * Setting the `Default Command Timeout' connection string option had no effect. (Bug #56806) * When an output parameter was declared as type `MySqlDbType.Bit', it failed to return with the correct value. (Bug #56756) * `MySqlHelper.ExecuteReader' did not include an overload accepting `MySqlParameter' objects when using a `MySqlConnection'. However, `MySqlHelper' did include an overload for `MySqlParameter' objects when using a string object containing the connection string to the database. (Bug #56755) * MySQL Connector/NET 6.1.3 (GA) would not install on a Windows Server 2008 (Web Edition) clean installation. There were two problems: * If .NET framework version 4.0 was not installed, installation failed because c:\windows\microsoft.net\v4.0.* did not exist. * If .NET 4.0 was subsequently installed, then the following error was generated: InstallFiles: File: MySql.Data.Entity.dll, Directory: , Size: 229888 MSI (s) (E0:AC) [15:20:26:196]: Assembly Error:The assembly is built by a runtime newer than the currently loaded runtime, and cannot be loaded. MSI (s) (E0:AC) [15:20:26:196]: Note: 1: 1935 2: 3: 0x8013101B 4: IStream 5: Commit 6: MSI (s) (E0:A0) [15:20:26:196]: Note: 1: 1304 2: MySql.Data.Entity.dll Error 1304. Error writing to file: MySql.Data.Entity.dll. Verify that you have access to that directory. (Bug #56580)  File: manual.info, Node: connector-net-news-6-3-4, Next: connector-net-news-6-3-3, Prev: connector-net-news-6-3-5, Up: changes-6.3.x D.4.2.4 Changes in MySQL Connector/NET 6.3.4 (01 September 2010 GA) ................................................................... First GA release. Fixes bugs since 6.3.3. *Bugs fixed:* * The calculation of `lockAge' in the Session Provider sometimes generated a `System.Data.SqlTypes.SqlNullValueException'. (Bug #55701) * Attempting to read `Double.MinValue' from a `DOUBLE' column in MySQL table generated the following exception: System.OverflowException : Value was either too large or too small for a Double. --OverflowException at System.Number.ParseDouble(String value, NumberStyles options, NumberFormatInfo numfmt) at MySql.Data.Types.MySqlDouble.MySql.Data.Types.IMySqlValue.ReadValue(MySqlPacket packet, Int64 length, Boolean nullVal) at MySql.Data.MySqlClient.NativeDriver.ReadColumnValue(Int32 index, MySqlField field, IMySqlValue valObject) at MySql.Data.MySqlClient.ResultSet.ReadColumnData(Boolean outputParms) at MySql.Data.MySqlClient.ResultSet.NextRow(CommandBehavior behavior) at MySql.Data.MySqlClient.MySqlDataReader.Read() (Bug #55644) * Calling `MySqlDataAdapter.Update(DataTable)' resulted in an unacceptable performance hit when updating large amounts of data. (Bug #55609) * If using MySQL Server 5.0.x it was not possible to alter stored routines in Visual Studio. If the stored routine was clicked, and the context sensitive menu option, Alter Routine, selected, the following error was generated: Unable to load object with error: Object reference not set to an instance of an object (Bug #55170) * EventLog was not disposed in the SessionState provider. (Bug #52550) * When attempting to carry out an operation such as: from p in db.Products where p.PostedDate>=DateTime.Now select p; Where `p.PostedDate' is a `DateTimeOffset', and the underlying column type is a `TIMESTAMP', the following exception was generated: MySqlException occurred Unable to serialize date/time value MySQL Connector/NET has now been changed so that all `TIMESTAMP' columns will be surfaced as `DateTime'. (Bug #52550) * Stored procedure enumeration code generated an error if a procedure was used in a dataset that did not return any resultsets. (Bug #50671) * The `INSERT' command was significantly slower with MySQL Connector/NET 6.x compared to 5.x, when compression was enabled. (Bug #48243) * Opening a connection in the Visual Studio Server Explorer and choosing to alter an existing routine required another authentication at the server. (Bug #44715)  File: manual.info, Node: connector-net-news-6-3-3, Next: connector-net-news-6-3-2, Prev: connector-net-news-6-3-4, Up: changes-6.3.x D.4.2.5 Changes in MySQL Connector/NET 6.3.3 (27 July 2010 beta) ................................................................ Second Beta release. Fixes bugs since 6.3.2. *Bugs fixed:* * `MySqlDataAdapter.Update()' generated concurrency violations for custom stored procedure driven update commands that used `UpdateRowSource.FirstReturnedRecord'. (Bug #54895) * Several calls to `datadapter.Update()' with intervening changes to `DataTable' resulted in `ConcurrencyException' exceptions being generated. (Bug #54863) * MySQL Connector/NET generated a null reference exception when `TransactionScope' was used by multiple threads. (Bug #54681) * The icon for the MySQL Web Configuration Tool was not displayed in Visual Studio for Web Application Projects. (Bug #54571) * The `MySqlHelper' object did not have an overloaded version of the `ExecuteReader' method that accepted a `MySqlConnection' object. (Bug #54570) * If `MySqlDataAdapter' was used with an `INSERT' command where the `VALUES' clause contained an expression with parentheses in it, and set the `adapter.UpdateBatchSize' parameter to be greater than one, then the call to `adapter.Update' either generated an exception or failed to batch the commands, executing each insert individually. (Bug #54386) * The method `MySql.Data.Common.QueryNormalizer.CollapseValueList' generated an `ArgumentOutOfRangeException'. (Bug #54152, Bug #53865) * MySQL Connector/NET did not process `Thread.Abort()' correctly, and failed to cancel queries currently running on the server. (Bug #54012) * MySQL Connector/NET 6.3.2 failed to install on Windows Vista. (Bug #53975) * Garbage Collector disposal of a `MySqlConnection' object caused the following exception: System.IO.EndOfStreamException: Attempted to read past the end of the stream. MySql.Data.MySqlClient.MySqlStream.ReadFully(Stream stream, Byte[] buffer, Int32 offset, Int32 count) MySql.Data.MySqlClient.MySqlStream.LoadPacket() Outer Exception Reading from the stream has failed. ... (Bug #53457) * MySQL Connector/NET did not throw an `EndOfStreamException' exception when `net_write_timeout' was exceeded. (Bug #53439) * After a timeout exception, if an attempt was made to reuse a connection returned to the connection pool the following exception was generated: [MySqlException (0x80004005): There is already an open DataReader associated with this Connection which must be closed first.] MySql.Data.MySqlClient.MySqlCommand.CheckState() +278 MySql.Data.MySqlClient.MySqlCommand.ExecuteReader(CommandBehavior behavior) +43 MySql.Data.MySqlClient.MySqlCommand.ExecuteReader() +6 Controls.SimpleCommand.ExecuteReader(String SQL) in ...:323 Albums.GetImagesByAlbum(SimpleCommand Cmd, Int32 iAlbum, String Order, String Limit) in ...:13 Forecast.Page_Load(Object sender, EventArgs e) in ...:70 System.Web.UI.Control.OnLoad(EventArgs e) +99 System.Web.UI.Control.LoadRecursive() +50 System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +627 (Bug #53357) * Membership schema creation failed if the default schema collation was not Latin1. (Bug #53174) * The MySQL Connector/NET installation failed due to `machine.config' files not being present in configuration folders. MySQL Connector/NET has been changed to skip over configuration folders that do not contain a `machine.config' file. (Bug #52352) * `CHAR(36)' columns were not recognized as GUIDs when used in views with entity models. (Bug #52085) * When an application was subjected to increased concurrent load, MySQL Connector/NET generated the following error when calling stored procedures: A DataTable named \'Procedure Parameters\' already belongs to this DataSet. (Bug #49118) * When the connection string option `Connection Reset = True' was used, a connection reset used the previously used encoding for the subsequent authentication operation. This failed, for example, if UCS2 was used to read the last column before the reset. (Bug #47153) * When batching was used in `MySqlDataAdapter', a connection was not opened automatically in `MySqlDataAdapter.Update()'. This resulted in an `InvalidOperationException' exception being generated, with the message text `connection must be valid and open'. MySQL Connector/NET has been changed to behave more like SQL Server: if the connection is closed, it is opened for the duration of update operation. (Bug #38411) * Database name was emitted into typed datasets. This prevented users using the configured default database. (Bug #33870)  File: manual.info, Node: connector-net-news-6-3-2, Next: connector-net-news-6-3-1, Prev: connector-net-news-6-3-3, Up: changes-6.3.x D.4.2.6 Changes in MySQL Connector/NET 6.3.2 (24 May 2010 beta) ............................................................... First Beta release. Fixes bugs since 6.3.1. *Functionality added or changed:* * Procedure cacheing had a problem whereby if you created a procedure, dropped it, and recreated it with a different number of parameters an exception was generated. MySQL Connector/NET has been changed so that if the procedure is recreated with a different number of parameters, it will still be recognized. (Bug #52562) * MySQL Connector/NET has been changed to include `MySqlDataReader.GetFieldType(string columnname)'. Further, `MySqlDataReader.GetOrdinal()' now includes the name of the column in the exception if the column is not found. (Bug #47467) *Bugs fixed:* * After an exception, the internal datareader, `MySqlCommand.Connection.Reader', was not properly closed (it was not set to null). If another query was subsequently executed on that command object an exception was generated with the message `There is already an open DataReader associated with this Connection which must be closed first.' (Bug #55558) * MySQL Connector/NET generated an exception when used to read a `TEXT' column containing more than 32767 bytes. (Bug #54040) * In MySQL Connector/NET, the `MySqlConnection.Abort()' method contained a `try...catch' construct, with an empty `catch' block. This meant that any exception generated at this point would not be caught. (Bug #52769) * The procedure cache affected the MySQL Connector/NET performance, reducing it by around 65%. This was due to unnecessary calls of `String.Format()', related to debug logging. Even though the logging was disabled the string was still being formatted, resulting in impaired performance. (Bug #52475) * If `FunctionsReturnString=true' was used in the connection string, the decimal separator (according to locale) was not interpreted. (Bug #52187) * In MySQL Connector/NET, the `LoadCharsetMap()' function of the `CharSetMap' class set the following incorrect mapping: mapping.Add("latin1", new CharacterSet("latin1", 1)); This meant that, for example, the Euro sign was not handled correctly. The correct mapping should have been: mapping.Add("latin1", new CharacterSet("windows-1252", 1)); This is because MySQL's `latin1' character set is the same as the `windows-cp1252' character set and it extends the official ISO 8859-1 or IANA latin1. (Bug #51927) * A non-terminated string in SQL threw a CLR exception rather than a syntax exception. (Bug #51788) * When calling `ExecuteNonQuery' on a command object, the following exception occurred: Index and length must refer to a location within the string. Parameter name: length (Bug #51610) * MySQL Connector/NET 6.3.1 failed to install. (Bug #51407, Bug #51604) * When using table per type inheritance and listing the contents of the parent table, the result of the query was a list of child objects, even though there was no related child record with the same parent Id. (Bug #49850)  File: manual.info, Node: connector-net-news-6-3-1, Next: connector-net-news-6-3-0, Prev: connector-net-news-6-3-2, Up: changes-6.3.x D.4.2.7 Changes in MySQL Connector/NET 6.3.1 (02 March 2010 alpha) .................................................................. Fixes bugs since 6.3.0. *Functionality added or changed:* * Connector/NET was not compatible with Visual Studio wizards that used square brackets to delimit symbols. Connector/NET has been changed to include a new connection string option `Sql Server mode' that supports use of square brackets to delimit symbols. (Bug #35852) *Bugs fixed:* * Specifying a connection string where an option had no value generated an error, rather than the value being set to the default. For example, a connection string such as the following would result in an error: server=localhost;user=root;compress=;database=test;port=3306;password=123456; (Bug #51209) * The method `Command.TrimSemicolons' used `StringBuilder', and therefore allocated memory for the query even if it did not need to be trimmed. This led to excessive memory consumption when executing a number of large queries. (Bug #51149) * `MySqlCommand.Parameters.Clear()' did not work. (Bug #50444) * Binary Columns were not displayed in the Query Builder of Visual Studio. (Bug #50171) * When the `UpdateBatchSize' property was set to a value greater than 1, only the first row was applied to the database. (Bug #50123) * When trying to create stored procedures from an SQL script, a `MySqlException' was thrown when attempting to redefine the `DELIMITER': MySql.Data.MySqlClient.MySqlException was unhandled Message="You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'DELIMITER' at line 1" Source="MySql.Data" ErrorCode=-2147467259 Number=1064 StackTrace: a` MySql.Data.MySqlClient.MySqlStream.ReadPacket() a` MySql.Data.MySqlClient.NativeDriver.ReadResult(UInt64& affectedRows, Int64& lastInsertId) a` MySql.Data.MySqlClient.MySqlDataReader.GetResultSet() a` MySql.Data.MySqlClient.MySqlDataReader.NextResult() a` MySql.Data.MySqlClient.MySqlCommand.ExecuteReader(CommandBehavior behavior) a` MySql.Data.MySqlClient.MySqlCommand.ExecuteReader() a` MySql.Data.MySqlClient.MySqlCommand.ExecuteNonQuery() a` MySql.Data.MySqlClient.MySqlScript.Execute() Note: The `MySqlScript' class has been fixed to support the delimiter statement as it is found in SQL scripts. (Bug #46429) * A connection string set in `web.config' could not be reused after Visual Studio 2008 Professional was shut down. It continued working for the existing controls, but did not work for new controls added. (Bug #41629)  File: manual.info, Node: connector-net-news-6-3-0, Prev: connector-net-news-6-3-1, Up: changes-6.3.x D.4.2.8 Changes in MySQL Connector/NET 6.3.0 (16 February 2010 alpha) ..................................................................... First alpha release of 6.3. *Functionality added or changed:* * Nested transaction scopes were not supported. MySQL Connector/NET now implements nested transaction scopes. A per-thread stack of scopes is maintained, which is necessary to handle nested scopes with the `RequiresNew' or `Suppress' options. (Bug #45098) * Support for MySQL Server 4.1 has been removed from MySQL Connector/NET starting with version 6.3.0. The connector will now throw an exception if you try to connect to a server of version less than 5.0. *Bugs fixed:* * When adding a data set in Visual Studio 2008, the following error was generated: Relations couldn't be addded. Column 'REFERENCED_TABLE_CATALOG' does not belong to table. This was due to a 'REFERENCED_TABLE_CATALOG' column not being included in the foreign keys collection. (Bug #48974) * Attempting to execute a load data local infile on a file where the user did not have write permissions, or the file was open in an editor gave an access denied error. (Bug #48944) * The method `MySqlDataReader.GetSchemaTable()' returned 0 in the `NumericPrecision' field for decimal and newdecimal columns. (Bug #48171)  File: manual.info, Node: changes-6.2.x, Next: changes-6.1.x, Prev: changes-6.3.x, Up: connector-net-news D.4.3 Changes in MySQL Connector/NET Version 6.2.x -------------------------------------------------- * Menu: * connector-net-news-6-2-5:: Changes in MySQL Connector/NET 6.2.5 (Not yet released GA) * connector-net-news-6-2-4:: Changes in MySQL Connector/NET 6.2.4 (30 August 2010 GA) * connector-net-news-6-2-3:: Changes in MySQL Connector/NET 6.2.3 (10 April 2010 GA) * connector-net-news-6-2-2:: Changes in MySQL Connector/NET 6.2.2 (22 December 2009 GA) * connector-net-news-6-2-1:: Changes in MySQL Connector/NET 6.2.1 (16 November 2009 beta) * connector-net-news-6-2-0:: Changes in MySQL Connector/NET 6.2.0 (21 October 2009 alpha)  File: manual.info, Node: connector-net-news-6-2-5, Next: connector-net-news-6-2-4, Prev: changes-6.2.x, Up: changes-6.2.x D.4.3.1 Changes in MySQL Connector/NET 6.2.5 (Not yet released GA) .................................................................. This release fixes bugs since 6.2.4. *Bugs fixed:* * `MysqlDataReader.GetSchemaTable' returned incorrect values and types. (Bug #59989, Bug #11776346) * All queries other than `INSERT' were executed individually instead of as a batch even though batching was enabled for the connection. (Bug #59616, Bug #11850286) * MySQL Connector/NET generated an exception when executing a query consisting of ';', for example: mycmd(";",mycon) mycmd.executenonquery() The exception generated was: System.IndexOutOfRangeException: Index was outside the bounds of the array. at MySql.Data.MySqlClient.MySqlCommand.TrimSemicolons(String sql) at MySql.Data.MySqlClient.MySqlCommand.ExecuteReader(CommandBehavior behavior) at MySql.Data.MySqlClient.MySqlCommand.ExecuteReader() at MySql.Data.MySqlClient.MySqlCommand.ExecuteNonQuery() (Bug #59537, Bug #11766433) * Setting `Membership.ApplicationName' had no effect. (Bug #59438, Bug #11770465) * A `NullReferenceException' was thrown on disposal of a `TransactionScope' object. (Bug #59346, Bug #11766272) * `MembershipProvider' did not generate hashes correctly if the algorithm was keyed. The Key of the algorithm should have been set if the `HashAlgorithm' was `KeyedHashAlgorithm'. (Bug #58906) * Code introduced to fix bug #54863 proved problematic on .NET version 3.5 and above. (Bug #58853) * The `MySqlTokenizer' contained unnecessary `Substring' and `Trim' calls: string token = sql.Substring(startIndex, stopIndex - startIndex).Trim(); The variable `token' was not used anywhere in the code. (Bug #58757) * `MySqlCommand.ExecuteReader(CommandBehavior)' threw a `NullReferenceException' when being called with `CommandBehavior.CloseConnection', if the SQL statement contained a syntax error, or contained invalid data such as an invalid column name. (Bug #58652) * `ReadFieldLength()' returned incorrect value for `BIGINT' autoincrement columns. (Bug #58373) * MySQL Connector/NET did not support the `utf8mb4' character set. When attempting to connect to `utf8mb4' tables or columns, an exception `KeyNotFoundException' was generated. (Bug #58244) * A typed dataset did not get the table name. (Bug #57894, Bug #11764989) * Setting `MySqlCommand.CommandTimeout' to 0 had no effect. It should have resulted in an infinite timeout. (Bug #57265) * When performing a row-by-row update, only the first row was updated and all other rows were ignored. (Bug #57092) * Setting the `Default Command Timeout' connection string option had no effect. (Bug #56806) * When an output parameter was declared as type `MySqlDbType.Bit', it failed to return with the correct value. (Bug #56756) * `MySqlHelper.ExecuteReader' did not include an overload accepting `MySqlParameter' objects when using a `MySqlConnection'. However, `MySqlHelper' did include an overload for `MySqlParameter' objects when using a string object containing the connection string to the database. (Bug #56755) * Default values returned for text columns were not quoted. This meant that the `COLUMN_DEFAULT' field of the `GetSchema' columns collection did not return a valid SQL expression. (Bug #56509) * MySQL Connector/NET for .NET/Mono attempted to dynamically load the assembly `Mono.Posix.dll' when a Unix socket was used to connect to the server. This failed and the connector was not able to use a Unix socket unless the `Mono.Posix.dll' assembly was previously loaded by the program. (Bug #56410) * The ADO.NET Entity Data Model could not add stored procedures from MySQL Server 5.0.45 but worked fine using MySQL Server 5.1. (Bug #55349)  File: manual.info, Node: connector-net-news-6-2-4, Next: connector-net-news-6-2-3, Prev: connector-net-news-6-2-5, Up: changes-6.2.x D.4.3.2 Changes in MySQL Connector/NET 6.2.4 (30 August 2010 GA) ................................................................ This release fixes bugs since 6.2.3. *Functionality added or changed:* * Procedure cacheing had a problem whereby if you created a procedure, dropped it, and recreated it with a different number of parameters an exception was generated. MySQL Connector/NET has been changed so that if the procedure is recreated with a different number of parameters, it will still be recognized. (Bug #52562) *Bugs fixed:* * The calculation of `lockAge' in the Session Provider sometimes generated a `System.Data.SqlTypes.SqlNullValueException'. (Bug #55701) * Attempting to read `Double.MinValue' from a `DOUBLE' column in MySQL table generated the following exception: System.OverflowException : Value was either too large or too small for a Double. --OverflowException at System.Number.ParseDouble(String value, NumberStyles options, NumberFormatInfo numfmt) at MySql.Data.Types.MySqlDouble.MySql.Data.Types.IMySqlValue.ReadValue(MySqlPacket packet, Int64 length, Boolean nullVal) at MySql.Data.MySqlClient.NativeDriver.ReadColumnValue(Int32 index, MySqlField field, IMySqlValue valObject) at MySql.Data.MySqlClient.ResultSet.ReadColumnData(Boolean outputParms) at MySql.Data.MySqlClient.ResultSet.NextRow(CommandBehavior behavior) at MySql.Data.MySqlClient.MySqlDataReader.Read() (Bug #55644) * After an exception, the internal datareader, `MySqlCommand.Connection.Reader', was not properly closed (it was not set to null). If another query was subsequently executed on that command object an exception was generated with the message `There is already an open DataReader associated with this Connection which must be closed first.' (Bug #55558) * If using MySQL Server 5.0.x it was not possible to alter stored routines in Visual Studio. If the stored routine was clicked, and the context sensitive menu option, Alter Routine, selected, the following error was generated: Unable to load object with error: Object reference not set to an instance of an object (Bug #55170) * `MySqlDataAdapter.Update()' generated concurrency violations for custom stored procedure driven update commands that used `UpdateRowSource.FirstReturnedRecord'. (Bug #54895) * Several calls to `datadapter.Update()' with intervening changes to `DataTable' resulted in `ConcurrencyException' exceptions being generated. (Bug #54863) * The icon for the MySQL Web Configuration Tool was not displayed in Visual Studio for Web Application Projects. (Bug #54571) * The `MySqlHelper' object did not have an overloaded version of the `ExecuteReader' method that accepted a `MySqlConnection' object. (Bug #54570) * If `MySqlDataAdapter' was used with an `INSERT' command where the `VALUES' clause contained an expression with parentheses in it, and set the `adapter.UpdateBatchSize' parameter to be greater than one, then the call to `adapter.Update' either generated an exception or failed to batch the commands, executing each insert individually. (Bug #54386) * The method `MySql.Data.Common.QueryNormalizer.CollapseValueList' generated an `ArgumentOutOfRangeException'. (Bug #54152, Bug #53865) * MySQL Connector/NET did not process `Thread.Abort()' correctly, and failed to cancel queries currently running on the server. (Bug #54012) * Garbage Collector disposal of a `MySqlConnection' object caused the following exception: System.IO.EndOfStreamException: Attempted to read past the end of the stream. MySql.Data.MySqlClient.MySqlStream.ReadFully(Stream stream, Byte[] buffer, Int32 offset, Int32 count) MySql.Data.MySqlClient.MySqlStream.LoadPacket() Outer Exception Reading from the stream has failed. ... (Bug #53457) * MySQL Connector/NET did not throw an `EndOfStreamException' exception when `net_write_timeout' was exceeded. (Bug #53439) * After a timeout exception, if an attempt was made to reuse a connection returned to the connection pool the following exception was generated: [MySqlException (0x80004005): There is already an open DataReader associated with this Connection which must be closed first.] MySql.Data.MySqlClient.MySqlCommand.CheckState() +278 MySql.Data.MySqlClient.MySqlCommand.ExecuteReader(CommandBehavior behavior) +43 MySql.Data.MySqlClient.MySqlCommand.ExecuteReader() +6 Controls.SimpleCommand.ExecuteReader(String SQL) in ...:323 Albums.GetImagesByAlbum(SimpleCommand Cmd, Int32 iAlbum, String Order, String Limit) in ...:13 Forecast.Page_Load(Object sender, EventArgs e) in ...:70 System.Web.UI.Control.OnLoad(EventArgs e) +99 System.Web.UI.Control.LoadRecursive() +50 System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +627 (Bug #53357) * Membership schema creation failed if the default schema collation was not Latin1. (Bug #53174) * In MySQL Connector/NET, the `MySqlConnection.Abort()' method contained a `try...catch' construct, with an empty `catch' block. This meant that any exception generated at this point would not be caught. (Bug #52769) * EventLog was not disposed in the SessionState provider. (Bug #52550) * The procedure cache affected the MySQL Connector/NET performance, reducing it by around 65%. This was due to unnecessary calls of `String.Format()', related to debug logging. Even though the logging was disabled the string was still being formatted, resulting in impaired performance. (Bug #52475) * If `FunctionsReturnString=true' was used in the connection string, the decimal separator (according to locale) was not interpreted. (Bug #52187) * Periodically the session provider threw an `SqlNullValueException' exception. When this happened, the row within the `my_aspnet_Sessions' table had `locked' always set to '1'. The locked status never changed back to '0' and the user experienced the exception on every page, until their browser was closed and reopened (recreating a new sessionID), or the `locked' value was manually changed to '0'. (Bug #52175) * `CHAR(36)' columns were not recognized as GUIDs when used in views with entity models. (Bug #52085) * In MySQL Connector/NET, the `LoadCharsetMap()' function of the `CharSetMap' class set the following incorrect mapping: mapping.Add("latin1", new CharacterSet("latin1", 1)); This meant that, for example, the Euro sign was not handled correctly. The correct mapping should have been: mapping.Add("latin1", new CharacterSet("windows-1252", 1)); This is because MySQL's `latin1' character set is the same as the `windows-cp1252' character set and it extends the official ISO 8859-1 or IANA latin1. (Bug #51927) * Stored procedure enumeration code generated an error if a procedure was used in a dataset that did not return any resultsets. (Bug #50671) * When an application was subjected to increased concurrent load, MySQL Connector/NET generated the following error when calling stored procedures: A DataTable named \'Procedure Parameters\' already belongs to this DataSet. (Bug #49118) * In the ADO.NET Entity Data Model Wizard, the time to update a model scaled abnormally as the number of entities increased. (Bug #48791, Bug #12596237) * The `INSERT' command was significantly slower with MySQL Connector/NET 6.x compared to 5.x, when compression was enabled. (Bug #48243) * When the connection string option `Connection Reset = True' was used, a connection reset used the previously used encoding for the subsequent authentication operation. This failed, for example, if UCS2 was used to read the last column before the reset. (Bug #47153) * Opening a connection in the Visual Studio Server Explorer and choosing to alter an existing routine required another authentication at the server. (Bug #44715) * When batching was used in `MySqlDataAdapter', a connection was not opened automatically in `MySqlDataAdapter.Update()'. This resulted in an `InvalidOperationException' exception being generated, with the message text `connection must be valid and open'. MySQL Connector/NET has been changed to behave more like SQL Server: if the connection is closed, it is opened for the duration of update operation. (Bug #38411) * Database name was emitted into typed datasets. This prevented users using the configured default database. (Bug #33870)  File: manual.info, Node: connector-net-news-6-2-3, Next: connector-net-news-6-2-2, Prev: connector-net-news-6-2-4, Up: changes-6.2.x D.4.3.3 Changes in MySQL Connector/NET 6.2.3 (10 April 2010 GA) ............................................................... This release fixes bugs since 6.2.2. *Functionality added or changed:* * MySQL Connector/NET has been changed to include `MySqlDataReader.GetFieldType(string columnname)'. Further, `MySqlDataReader.GetOrdinal()' now includes the name of the column in the exception if the column is not found. (Bug #47467) *Bugs fixed:* * A non-terminated string in SQL threw a CLR exception rather than a syntax exception. (Bug #51788) * When calling `ExecuteNonQuery' on a command object, the following exception occurred: Index and length must refer to a location within the string. Parameter name: length (Bug #51610) * Specifying a connection string where an option had no value generated an error, rather than the value being set to the default. For example, a connection string such as the following would result in an error: server=localhost;user=root;compress=;database=test;port=3306;password=123456; (Bug #51209) * The method `Command.TrimSemicolons' used `StringBuilder', and therefore allocated memory for the query even if it did not need to be trimmed. This led to excessive memory consumption when executing a number of large queries. (Bug #51149) * `MySqlCommand.Parameters.Clear()' did not work. (Bug #50444) * When the `MySqlScript.execute()' method was called, the following exception was generated: InvalidOperationException : The CommandText property has not been properly initialized. (Bug #50344) * When using the Compact Framework the following exception occurred when attempting to connect to a MySQL Server: System.InvalidOperationException was unhandled Message="Timeouts are not supported on this stream." (Bug #50321) * Binary Columns were not displayed in the Query Builder of Visual Studio. (Bug #50171) * When the `UpdateBatchSize' property was set to a value greater than 1, only the first row was applied to the database. (Bug #50123) * When using table per type inheritance and listing the contents of the parent table, the result of the query was a list of child objects, even though there was no related child record with the same parent Id. (Bug #49850) * `MySqlDataReader.GetUInt64' returned an incorrect value when reading a `BIGINT UNSIGNED' column containing a value greater than 2147483647. (Bug #49794) * A `FormatException' was generated when an empty string was returned from a stored function. (Bug #49642) * When trying to create stored procedures from an SQL script, a `MySqlException' was thrown when attempting to redefine the `DELIMITER': MySql.Data.MySqlClient.MySqlException was unhandled Message="You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'DELIMITER' at line 1" Source="MySql.Data" ErrorCode=-2147467259 Number=1064 StackTrace: a` MySql.Data.MySqlClient.MySqlStream.ReadPacket() a` MySql.Data.MySqlClient.NativeDriver.ReadResult(UInt64& affectedRows, Int64& lastInsertId) a` MySql.Data.MySqlClient.MySqlDataReader.GetResultSet() a` MySql.Data.MySqlClient.MySqlDataReader.NextResult() a` MySql.Data.MySqlClient.MySqlCommand.ExecuteReader(CommandBehavior behavior) a` MySql.Data.MySqlClient.MySqlCommand.ExecuteReader() a` MySql.Data.MySqlClient.MySqlCommand.ExecuteNonQuery() a` MySql.Data.MySqlClient.MySqlScript.Execute() Note: The `MySqlScript' class has been fixed to support the delimiter statement as it is found in SQL scripts. (Bug #46429) * Calling a User Defined Function using Entity SQL in the Entity Framework caused a `NullReferenceException'. (Bug #45277) * A connection string set in `web.config' could not be reused after Visual Studio 2008 Professional was shut down. It continued working for the existing controls, but did not work for new controls added. (Bug #41629)  File: manual.info, Node: connector-net-news-6-2-2, Next: connector-net-news-6-2-1, Prev: connector-net-news-6-2-3, Up: changes-6.2.x D.4.3.4 Changes in MySQL Connector/NET 6.2.2 (22 December 2009 GA) .................................................................. First GA release of 6.2. This release fixes bugs since 6.2.1. *Bugs fixed:* * When adding a data set in Visual Studio 2008, the following error was generated: Relations couldn't be addded. Column 'REFERENCED_TABLE_CATALOG' does not belong to table. This was due to a 'REFERENCED_TABLE_CATALOG' column not being included in the foreign keys collection. (Bug #48974) * Attempting to execute a load data local infile on a file where the user did not have write permissions, or the file was open in an editor gave an access denied error. (Bug #48944) * The method `MySqlDataReader.GetSchemaTable()' returned 0 in the `NumericPrecision' field for decimal and newdecimal columns. (Bug #48171) * MySQL Connector/NET generated an invalid operation exception during a transaction rollback: System.InvalidOperationException: Connection must be valid and open to rollback transaction at MySql.Data.MySqlClient.MySqlTransaction.Rollback() at MySql.Data.MySqlClient.MySqlConnection.CloseFully() at MySql.Data.MySqlClient.MySqlPromotableTransaction.System.Transactions.IPromotableSinglePhaseNotification.Rollback(SinglePhaseEnlistment singlePhaseEnlistment) ... (Bug #35330) * Connection objects were not garbage collected when not in use. (Bug #31996)  File: manual.info, Node: connector-net-news-6-2-1, Next: connector-net-news-6-2-0, Prev: connector-net-news-6-2-2, Up: changes-6.2.x D.4.3.5 Changes in MySQL Connector/NET 6.2.1 (16 November 2009 beta) .................................................................... This release fixes bugs since 6.2.0. *Functionality added or changed:* * The `MySqlParameter' class now has a property named `PossibleValues'. This property is NULL unless the parameter is created by `MySqlCommandBuilder.DeriveParameters'. Further, it will be NULL unless the parameter is of type enum or set - in this case it will be a list of strings that are the possible values for the column. This feature is designed as an aid to the developer. (Bug #48586) * Prior to MySQL Connector/NET 6.2, `MySqlCommand.CommandTimeout' included user processing time, that is processing time not related to direct use of the connector. Timeout was implemented through a .NET Timer, that triggered after `CommandTimeout' seconds. MySQL Connector/NET 6.2 introduced timeouts that are aligned with how Microsoft handles `SqlCommand.CommandTimeout'. This property is the cumulative timeout for all network reads and writes during command execution or processing of the results. A timeout can still occur in the `MySqlReader.Read' method after the first row is returned, and does not include user processing time, only IO operations. Further details on this can be found in the relevant Microsoft documentation (http://msdn.microsoft.com/en-us/library/system.data.sqlclient.sqlcommand.commandtimeout.aspx). * Starting with MySQL Connector/NET 6.2, there is a background job that runs every three minutes and removes connections from pool that have been idle (unused) for more than three minutes. The pool cleanup frees resources on both client and server side. This is because on the client side every connection uses a socket, and on the server side every connection uses a socket and a thread. Prior to this change, connections were never removed from the pool, and the pool always contained the peak number of open connections. For example, a web application that peaked at 1000 concurrent database connections would consume 1000 threads and 1000 open sockets at the server, without ever freeing up those resources from the connection pool. * MySQL Connector/NET now supports the processing of certificates when connecting to an SSL-enabled MySQL Server. For further information see the connection string option SSL Mode in the section *Note connector-net-connection-options:: and the tutorial *Note connector-net-tutorials-ssl::. *Bugs fixed:* * Cloning of `MySqlCommand' was not typesafe. To clone a `MySqlCommand' it was necessary to do: MySqlCommand clone = (MySqlCommand)((ICloneable)comm).Clone(); MySQL Connector/NET was changed so that it was possible to do: MySqlCommand clone = comm.Clone(); (Bug #48460) * When used, the `Encrypt' connection string option caused a `Keyword not supported' exception to be generated. This option is in fact obsolete, and the option SSL Mode should be used instead. Although the `Encrypt' option has been fixed so that it does not generate an exception, it will be removed completely in version 6.4. (Bug #48290) * When building the `MySql.Data' project with .NET Framework 3.5 installed, the following build output was displayed: Project file contains ToolsVersion="4.0", which is not supported by this version of MSBuild. Treating the project as if it had ToolsVersion="3.5". The project had been created using the .NET Framework 4.0, which was beta, instead of using the 3.5 framework. (Bug #48271) * It was not possible to retrieve a value from a MySQL server table, if the value was larger than that supported by the .NET type `System.Decimal'. MySQL Connector/NET was changed to expose the `MySqlDecimal' type, along with the supporting method `GetMySqlDecimal'. (Bug #48100) * An entity model created from a schema containing a table with a column of type `UNSIGNED BIGINT' and a view of the table did not behave correctly. When an entity was created and mapped to the view, the column that was of type `UNSIGNED BIGINT' was displayed as `BIGINT'. (Bug #47872) * MySQL Connector/NET session support did not work with MySQL Server versions prior to 5.0, as the Session Provider used a call to `TIMESTAMPDIFF', which was not available on servers prior to 5.0. (Bug #47219)  File: manual.info, Node: connector-net-news-6-2-0, Prev: connector-net-news-6-2-1, Up: changes-6.2.x D.4.3.6 Changes in MySQL Connector/NET 6.2.0 (21 October 2009 alpha) .................................................................... The first alpha release of 6.2. *Bugs fixed:* * When using a `BINARY(16)' column to represent a GUID and having specified `old guids = true' in the connection string, the values were returned correctly until a null value was encountered in that field. After the null value was encountered a format exception was thrown with the following message: Guid should contain 32 digits with 4 dashes (xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx). (Bug #47928) * The Session Provider created invalid `session expires' on a random basis. This was due to the fact that the Session Provider was incorrectly reading from the root `web.config', rather than from the application specific `web.config'. (Bug #47815) * When loading the `MySQLClient-mono.sln' file included with the Connector/NET source into Mono Develop, the following error occurred: /home/tbedford/connector-net-src/6.1/MySQLClient-mono.sln(22): Unsupported or unrecognized project: '/home/tbedford/connector-net-src/6.1/Installer/Installer.wixproj' If the file was modified to remove this problem, then attempting to build the solution generated the following error: /home/tbedford/connector-net-src/6.1/MySql.Data/Provider/Source/Connection.cs(280,46): error CS0115: `MySql.Data.MySqlClient.MySqlConnection.DbProviderFactory' is marked as an override but no suitable property found to override (Bug #47048)  File: manual.info, Node: changes-6.1.x, Next: changes-6.0.x, Prev: changes-6.2.x, Up: connector-net-news D.4.4 Changes in MySQL Connector/NET Version 6.1.x -------------------------------------------------- * Menu: * connector-net-news-6-1-6:: Changes in MySQL Connector/NET 6.1.6 (Not yet released GA) * connector-net-news-6-1-5:: Changes in MySQL Connector/NET 6.1.5 (30 August 2010 GA) * connector-net-news-6-1-4:: Changes in MySQL Connector/NET 6.1.4 (28 April 2010 GA) * connector-net-news-6-1-3:: Changes in MySQL Connector/NET 6.1.3 (16 November 2009 GA) * connector-net-news-6-1-2:: Changes in MySQL Connector/NET 6.1.2 (08 September 2009 GA) * connector-net-news-6-1-1:: Changes in MySQL Connector/NET 6.1.1 (20 August 2009 beta) * connector-net-news-6-1-0:: Changes in MySQL Connector/NET 6.1.0 (15 July 2009 alpha)  File: manual.info, Node: connector-net-news-6-1-6, Next: connector-net-news-6-1-5, Prev: changes-6.1.x, Up: changes-6.1.x D.4.4.1 Changes in MySQL Connector/NET 6.1.6 (Not yet released GA) .................................................................. This release fixes bugs since 6.1.5. *Bugs fixed:* * `MysqlDataReader.GetSchemaTable' returned incorrect values and types. (Bug #59989, Bug #11776346) * All queries other than `INSERT' were executed individually instead of as a batch even though batching was enabled for the connection. (Bug #59616, Bug #11850286) * MySQL Connector/NET generated an exception when executing a query consisting of ';', for example: mycmd(";",mycon) mycmd.executenonquery() The exception generated was: System.IndexOutOfRangeException: Index was outside the bounds of the array. at MySql.Data.MySqlClient.MySqlCommand.TrimSemicolons(String sql) at MySql.Data.MySqlClient.MySqlCommand.ExecuteReader(CommandBehavior behavior) at MySql.Data.MySqlClient.MySqlCommand.ExecuteReader() at MySql.Data.MySqlClient.MySqlCommand.ExecuteNonQuery() (Bug #59537, Bug #11766433) * Setting `Membership.ApplicationName' had no effect. (Bug #59438, Bug #11770465) * `MembershipProvider' did not generate hashes correctly if the algorithm was keyed. The Key of the algorithm should have been set if the `HashAlgorithm' was `KeyedHashAlgorithm'. (Bug #58906) * Code introduced to fix bug #54863 proved problematic on .NET version 3.5 and above. (Bug #58853) * The `MySqlTokenizer' contained unnecessary `Substring' and `Trim' calls: string token = sql.Substring(startIndex, stopIndex - startIndex).Trim(); The variable `token' was not used anywhere in the code. (Bug #58757) * `MySqlCommand.ExecuteReader(CommandBehavior)' threw a `NullReferenceException' when being called with `CommandBehavior.CloseConnection', if the SQL statement contained a syntax error, or contained invalid data such as an invalid column name. (Bug #58652) * `ReadFieldLength()' returned incorrect value for `BIGINT' autoincrement columns. (Bug #58373) * MySQL Connector/NET did not support the `utf8mb4' character set. When attempting to connect to `utf8mb4' tables or columns, an exception `KeyNotFoundException' was generated. (Bug #58244) * A typed dataset did not get the table name. (Bug #57894, Bug #11764989) * Setting `MySqlCommand.CommandTimeout' to 0 had no effect. It should have resulted in an infinite timeout. (Bug #57265) * When performing a row-by-row update, only the first row was updated and all other rows were ignored. (Bug #57092) * Setting the `Default Command Timeout' connection string option had no effect. (Bug #56806) * When an output parameter was declared as type `MySqlDbType.Bit', it failed to return with the correct value. (Bug #56756) * `MySqlHelper.ExecuteReader' did not include an overload accepting `MySqlParameter' objects when using a `MySqlConnection'. However, `MySqlHelper' did include an overload for `MySqlParameter' objects when using a string object containing the connection string to the database. (Bug #56755) * Default values returned for text columns were not quoted. This meant that the `COLUMN_DEFAULT' field of the `GetSchema' columns collection did not return a valid SQL expression. (Bug #56509) * MySQL Connector/NET for .NET/Mono attempted to dynamically load the assembly `Mono.Posix.dll' when a Unix socket was used to connect to the server. This failed and the connector was not able to use a Unix socket unless the `Mono.Posix.dll' assembly was previously loaded by the program. (Bug #56410) * The ADO.NET Entity Data Model could not add stored procedures from MySQL Server 5.0.45 but worked fine using MySQL Server 5.1. (Bug #55349)  File: manual.info, Node: connector-net-news-6-1-5, Next: connector-net-news-6-1-4, Prev: connector-net-news-6-1-6, Up: changes-6.1.x D.4.4.2 Changes in MySQL Connector/NET 6.1.5 (30 August 2010 GA) ................................................................ This release fixes bugs since 6.1.4. *Bugs fixed:* * The calculation of `lockAge' in the Session Provider sometimes generated a `System.Data.SqlTypes.SqlNullValueException'. (Bug #55701) * Attempting to read `Double.MinValue' from a `DOUBLE' column in MySQL table generated the following exception: System.OverflowException : Value was either too large or too small for a Double. --OverflowException at System.Number.ParseDouble(String value, NumberStyles options, NumberFormatInfo numfmt) at MySql.Data.Types.MySqlDouble.MySql.Data.Types.IMySqlValue.ReadValue(MySqlPacket packet, Int64 length, Boolean nullVal) at MySql.Data.MySqlClient.NativeDriver.ReadColumnValue(Int32 index, MySqlField field, IMySqlValue valObject) at MySql.Data.MySqlClient.ResultSet.ReadColumnData(Boolean outputParms) at MySql.Data.MySqlClient.ResultSet.NextRow(CommandBehavior behavior) at MySql.Data.MySqlClient.MySqlDataReader.Read() (Bug #55644) * If using MySQL Server 5.0.x it was not possible to alter stored routines in Visual Studio. If the stored routine was clicked, and the context sensitive menu option, Alter Routine, selected, the following error was generated: Unable to load object with error: Object reference not set to an instance of an object (Bug #55170) * `MySqlDataAdapter.Update()' generated concurrency violations for custom stored procedure driven update commands that used `UpdateRowSource.FirstReturnedRecord'. (Bug #54895) * Several calls to `datadapter.Update()' with intervening changes to `DataTable' resulted in `ConcurrencyException' exceptions being generated. (Bug #54863) * The icon for the MySQL Web Configuration Tool was not displayed in Visual Studio for Web Application Projects. (Bug #54571) * The `MySqlHelper' object did not have an overloaded version of the `ExecuteReader' method that accepted a `MySqlConnection' object. (Bug #54570) * If `MySqlDataAdapter' was used with an `INSERT' command where the `VALUES' clause contained an expression with parentheses in it, and set the `adapter.UpdateBatchSize' parameter to be greater than one, then the call to `adapter.Update' either generated an exception or failed to batch the commands, executing each insert individually. (Bug #54386) * The method `MySql.Data.Common.QueryNormalizer.CollapseValueList' generated an `ArgumentOutOfRangeException'. (Bug #54152, Bug #53865) * Garbage Collector disposal of a `MySqlConnection' object caused the following exception: System.IO.EndOfStreamException: Attempted to read past the end of the stream. MySql.Data.MySqlClient.MySqlStream.ReadFully(Stream stream, Byte[] buffer, Int32 offset, Int32 count) MySql.Data.MySqlClient.MySqlStream.LoadPacket() Outer Exception Reading from the stream has failed. ... (Bug #53457) * MySQL Connector/NET did not throw an `EndOfStreamException' exception when `net_write_timeout' was exceeded. (Bug #53439) * After a timeout exception, if an attempt was made to reuse a connection returned to the connection pool the following exception was generated: [MySqlException (0x80004005): There is already an open DataReader associated with this Connection which must be closed first.] MySql.Data.MySqlClient.MySqlCommand.CheckState() +278 MySql.Data.MySqlClient.MySqlCommand.ExecuteReader(CommandBehavior behavior) +43 MySql.Data.MySqlClient.MySqlCommand.ExecuteReader() +6 Controls.SimpleCommand.ExecuteReader(String SQL) in ...:323 Albums.GetImagesByAlbum(SimpleCommand Cmd, Int32 iAlbum, String Order, String Limit) in ...:13 Forecast.Page_Load(Object sender, EventArgs e) in ...:70 System.Web.UI.Control.OnLoad(EventArgs e) +99 System.Web.UI.Control.LoadRecursive() +50 System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +627 (Bug #53357) * Membership schema creation failed if the default schema collation was not Latin1. (Bug #53174) * EventLog was not disposed in the SessionState provider. (Bug #52550) * `CHAR(36)' columns were not recognized as GUIDs when used in views with entity models. (Bug #52085) * Stored procedure enumeration code generated an error if a procedure was used in a dataset that did not return any resultsets. (Bug #50671) * When an application was subjected to increased concurrent load, MySQL Connector/NET generated the following error when calling stored procedures: A DataTable named \'Procedure Parameters\' already belongs to this DataSet. (Bug #49118) * In the ADO.NET Entity Data Model Wizard, the time to update a model scaled abnormally as the number of entities increased. (Bug #48791, Bug #12596237) * The `INSERT' command was significantly slower with MySQL Connector/NET 6.x compared to 5.x, when compression was enabled. (Bug #48243) * When the connection string option `Connection Reset = True' was used, a connection reset used the previously used encoding for the subsequent authentication operation. This failed, for example, if UCS2 was used to read the last column before the reset. (Bug #47153) * Opening a connection in the Visual Studio Server Explorer and choosing to alter an existing routine required another authentication at the server. (Bug #44715) * When batching was used in `MySqlDataAdapter', a connection was not opened automatically in `MySqlDataAdapter.Update()'. This resulted in an `InvalidOperationException' exception being generated, with the message text `connection must be valid and open'. MySQL Connector/NET has been changed to behave more like SQL Server: if the connection is closed, it is opened for the duration of update operation. (Bug #38411) * Database name was emitted into typed datasets. This prevented users using the configured default database. (Bug #33870)  File: manual.info, Node: connector-net-news-6-1-4, Next: connector-net-news-6-1-3, Prev: connector-net-news-6-1-5, Up: changes-6.1.x D.4.4.3 Changes in MySQL Connector/NET 6.1.4 (28 April 2010 GA) ............................................................... This release fixes bugs since 6.1.3. *Functionality added or changed:* * Procedure cacheing had a problem whereby if you created a procedure, dropped it, and recreated it with a different number of parameters an exception was generated. MySQL Connector/NET has been changed so that if the procedure is recreated with a different number of parameters, it will still be recognized. (Bug #52562) * MySQL Connector/NET has been changed to include `MySqlDataReader.GetFieldType(string columnname)'. Further, `MySqlDataReader.GetOrdinal()' now includes the name of the column in the exception if the column is not found. (Bug #47467) *Bugs fixed:* * In MySQL Connector/NET, the `MySqlConnection.Abort()' method contained a `try...catch' construct, with an empty `catch' block. This meant that any exception generated at this point would not be caught. (Bug #52769) * If `FunctionsReturnString=true' was used in the connection string, the decimal separator (according to locale) was not interpreted. (Bug #52187) * In MySQL Connector/NET, the `LoadCharsetMap()' function of the `CharSetMap' class set the following incorrect mapping: mapping.Add("latin1", new CharacterSet("latin1", 1)); This meant that, for example, the Euro sign was not handled correctly. The correct mapping should have been: mapping.Add("latin1", new CharacterSet("windows-1252", 1)); This is because MySQL's `latin1' character set is the same as the `windows-cp1252' character set and it extends the official ISO 8859-1 or IANA latin1. (Bug #51927) * A non-terminated string in SQL threw a CLR exception rather than a syntax exception. (Bug #51788) * When calling `ExecuteNonQuery' on a command object, the following exception occurred: Index and length must refer to a location within the string. Parameter name: length (Bug #51610) * The method `Command.TrimSemicolons' used `StringBuilder', and therefore allocated memory for the query even if it did not need to be trimmed. This led to excessive memory consumption when executing a number of large queries. (Bug #51149) * `MySqlCommand.Parameters.Clear()' did not work. (Bug #50444) * When the `MySqlScript.execute()' method was called, the following exception was generated: InvalidOperationException : The CommandText property has not been properly initialized. (Bug #50344) * Binary Columns were not displayed in the Query Builder of Visual Studio. (Bug #50171) * When the `UpdateBatchSize' property was set to a value greater than 1, only the first row was applied to the database. (Bug #50123) * When using table per type inheritance and listing the contents of the parent table, the result of the query was a list of child objects, even though there was no related child record with the same parent Id. (Bug #49850) * `MySqlDataReader.GetUInt64' returned an incorrect value when reading a `BIGINT UNSIGNED' column containing a value greater than 2147483647. (Bug #49794) * A `FormatException' was generated when an empty string was returned from a stored function. (Bug #49642) * When adding a data set in Visual Studio 2008, the following error was generated: Relations couldn't be addded. Column 'REFERENCED_TABLE_CATALOG' does not belong to table. This was due to a 'REFERENCED_TABLE_CATALOG' column not being included in the foreign keys collection. (Bug #48974) * Attempting to execute a load data local infile on a file where the user did not have write permissions, or the file was open in an editor gave an access denied error. (Bug #48944) * The method `MySqlDataReader.GetSchemaTable()' returned 0 in the `NumericPrecision' field for decimal and newdecimal columns. (Bug #48171) * When trying to create stored procedures from an SQL script, a `MySqlException' was thrown when attempting to redefine the `DELIMITER': MySql.Data.MySqlClient.MySqlException was unhandled Message="You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'DELIMITER' at line 1" Source="MySql.Data" ErrorCode=-2147467259 Number=1064 StackTrace: a` MySql.Data.MySqlClient.MySqlStream.ReadPacket() a` MySql.Data.MySqlClient.NativeDriver.ReadResult(UInt64& affectedRows, Int64& lastInsertId) a` MySql.Data.MySqlClient.MySqlDataReader.GetResultSet() a` MySql.Data.MySqlClient.MySqlDataReader.NextResult() a` MySql.Data.MySqlClient.MySqlCommand.ExecuteReader(CommandBehavior behavior) a` MySql.Data.MySqlClient.MySqlCommand.ExecuteReader() a` MySql.Data.MySqlClient.MySqlCommand.ExecuteNonQuery() a` MySql.Data.MySqlClient.MySqlScript.Execute() Note: The `MySqlScript' class has been fixed to support the delimiter statement as it is found in SQL scripts. (Bug #46429) * Calling a User Defined Function using Entity SQL in the Entity Framework caused a `NullReferenceException'. (Bug #45277) * A connection string set in `web.config' could not be reused after Visual Studio 2008 Professional was shut down. It continued working for the existing controls, but did not work for new controls added. (Bug #41629)  File: manual.info, Node: connector-net-news-6-1-3, Next: connector-net-news-6-1-2, Prev: connector-net-news-6-1-4, Up: changes-6.1.x D.4.4.4 Changes in MySQL Connector/NET 6.1.3 (16 November 2009 GA) .................................................................. This release fixes bugs since 6.1.2. *Bugs fixed:* * Cloning of `MySqlCommand' was not typesafe. To clone a `MySqlCommand' it was necessary to do: MySqlCommand clone = (MySqlCommand)((ICloneable)comm).Clone(); MySQL Connector/NET was changed so that it was possible to do: MySqlCommand clone = comm.Clone(); (Bug #48460) * When building the `MySql.Data' project with .NET Framework 3.5 installed, the following build output was displayed: Project file contains ToolsVersion="4.0", which is not supported by this version of MSBuild. Treating the project as if it had ToolsVersion="3.5". The project had been created using the .NET Framework 4.0, which was beta, instead of using the 3.5 framework. (Bug #48271) * If `MySqlConnection.GetSchema' was called for "Indexes" on a table named `b`a`d' as follows: DataTable schemaPrimaryKeys = connection.GetSchema( "Indexes", new string[] { null, schemaName, "b`a`d"}); Then the following exception was generated: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'a`d`' at line 1 (Bug #48101) * It was not possible to retrieve a value from a MySQL server table, if the value was larger than that supported by the .NET type `System.Decimal'. MySQL Connector/NET was changed to expose the `MySqlDecimal' type, along with the supporting method `GetMySqlDecimal'. (Bug #48100) * For some character sets such as UTF-8, a `CHAR' column would sometimes be incorrectly interpreted as a `GUID' by MySQL Connector/NET. MySQL Connector/NET was changed so that a column would only be interpreted as a `GUID' if it had a character length of 36, as opposed to a byte length of 36. (Bug #47985) * When using a `BINARY(16)' column to represent a GUID and having specified `old guids = true' in the connection string, the values were returned correctly until a null value was encountered in that field. After the null value was encountered a format exception was thrown with the following message: Guid should contain 32 digits with 4 dashes (xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx). (Bug #47928) * An entity model created from a schema containing a table with a column of type `UNSIGNED BIGINT' and a view of the table did not behave correctly. When an entity was created and mapped to the view, the column that was of type `UNSIGNED BIGINT' was displayed as `BIGINT'. (Bug #47872) * The Session Provider created invalid `session expires' on a random basis. This was due to the fact that the Session Provider was incorrectly reading from the root `web.config', rather than from the application specific `web.config'. (Bug #47815) * Attempting to build MySQL Connector/NET 6.1 `MySQL.Data' from source code on Windows failed with the following error: ...\clones\6.1\MySql.Data\Provider\Source\NativeDriver.cs(519,29): error CS0122: 'MySql.Data.MySqlClient.MySqlPacket.MySqlPacket()' is inaccessible due to its protection level (Bug #47354) * When tables were auto created for the Session State Provider they were set to use the MySQL Server's default collation, rather than the default collation set for the containing database. (Bug #47332) * When loading the `MySQLClient-mono.sln' file included with the Connector/NET source into Mono Develop, the following error occurred: /home/tbedford/connector-net-src/6.1/MySQLClient-mono.sln(22): Unsupported or unrecognized project: '/home/tbedford/connector-net-src/6.1/Installer/Installer.wixproj' If the file was modified to remove this problem, then attempting to build the solution generated the following error: /home/tbedford/connector-net-src/6.1/MySql.Data/Provider/Source/Connection.cs(280,46): error CS0115: `MySql.Data.MySqlClient.MySqlConnection.DbProviderFactory' is marked as an override but no suitable property found to override (Bug #47048)  File: manual.info, Node: connector-net-news-6-1-2, Next: connector-net-news-6-1-1, Prev: connector-net-news-6-1-3, Up: changes-6.1.x D.4.4.5 Changes in MySQL Connector/NET 6.1.2 (08 September 2009 GA) ................................................................... This is the first GA release of 6.1. *Bugs fixed:* * The MySQL Connector/NET Session State Provider truncated session data to 64KB, due to its column types being set to `BLOB'. (Bug #47339) * MySQL Connector/NET generated the following exception when using the Session State provider: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'MINUTEWHERE SessionId = 'dtmgga55x35oi255nrfrxe45' AND ApplicationId = 1 AND Loc' at line 1 Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. Exception Details: MySql.Data.MySqlClient.MySqlException: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'MINUTEWHERE SessionId = 'dtmgga55x35oi255nrfrxe45' AND ApplicationId = 1 AND Loc' at line 1 (Bug #46939) * If an error occurred during connection to a MySQL Server, deserializing the error message from the packet buffer caused a `NullReferenceException' to be thrown. When the method `MySqlPacket::ReadString()' attempted to retrieve the error message, the following line of code threw the exception: string s = encoding.GetString(bits, (int)buffer.Position, end - (int)buffer.Position); This was due to the fact that the encoding field had not been initialized correctly. (Bug #46844) * Input parameters were missing from Stored Procedures when using them with ADO.NET Data Entities. (Bug #44985) * MySQL Connector/NET did not time out correctly. The command timeout was set to 30 secs, but MySQL Connector/NET hung for several hours. (Bug #43761)  File: manual.info, Node: connector-net-news-6-1-1, Next: connector-net-news-6-1-0, Prev: connector-net-news-6-1-2, Up: changes-6.1.x D.4.4.6 Changes in MySQL Connector/NET 6.1.1 (20 August 2009 beta) .................................................................. This is the first Beta release of 6.1. *Bugs fixed:* * In the `MySqlDataReader' class the `GetSByte' function returned a `byte' value instead of an `sbyte' value. (Bug #46620) * The MySQL Connector/NET Profile Provider, `MySql.Web.Profile.MySQLProfileProvider', generated an error when running on Mono. When an attempt was made to save a string in `Profile.Name' the string was not saved to the `my_aspnet_Profiles' table. If an attempt was made to force the save with `Profile.Save()' the following error was generated: Server Error in '/mono' Application -------------------------------------------------------------------------------- The requested feature is not implemented. Description: HTTP 500. Error processing request. Stack Trace: System.NotImplementedException: The requested feature is not implemented. at MySql.Data.MySqlClient.MySqlConnection.EnlistTransaction (System.Transactions.Transaction transaction) [0x00000] at MySql.Data.MySqlClient.MySqlConnection.Open () [0x00000] at MySql.Web.Profile.MySQLProfileProvider.SetPropertyValues (System.Configuration.SettingsContext context, System.Configuration.SettingsPropertyValueCollection collection) [0x00000] -------------------------------------------------------------------------------- Version information: Mono Version: 2.0.50727.1433; ASP.NET Version: 2.0.50727.1433 (Bug #46375) * An exception was generated when using `TIMESTAMP' columns with the Entity Framework. (Bug #46311) * MySQL Connector/NET sometimes hung, without generating an exception. This happened if a read from a stream failed returning a 0, causing the code in `LoadPacket()' to enter an infinite loop. (Bug #46308) * When using MySQL Connector/NET 6.0.4 and a MySQL Server 4.1 an exception was generated when trying to execute: connection.GetSchema("Columns", ...); The exception generated was: 'connection.GetSchema("Columns")' threw an exception of type 'System.ArgumentException'System.Data.DataTable {System.ArgumentException} base{"Input string was not in a correct format.Couldn't store <'Select'> in NUMERIC_PRECISION Column. Expected type is UInt64."}System.Exception {System.ArgumentException} (Bug #46270) * The MySQL Connector/NET method `StoredProcedure.GetParameters(string)' ignored the programmer's setting of the `UseProcedureBodies' option. This broke any application for which the application's parameter names did not match the parameter names in the Stored Procedure, resulting in an `ArgumentException' with the message `Parameter 'foo' not found in the collection.' and the following stack trace: MySql.Data.dll!MySql.Data.MySqlClient.MySqlParameterCollection.GetParameterFlexible(stri ng parameterName = "pStart", bool throwOnNotFound = true) Line 459C# MySql.Data.dll!MySql.Data.MySqlClient.StoredProcedure.Resolve() Line 157 + 0x25 bytesC# MySql.Data.dll!MySql.Data.MySqlClient.MySqlCommand.ExecuteReader(System.Data.CommandBeha vior behavior = SequentialAccess) Line 405 + 0xb bytesC# MySql.Data.dll!MySql.Data.MySqlClient.MySqlCommand.ExecuteDbDataReader(System.Data.Comma ndBehavior behavior = SequentialAccess) Line 884 + 0xb bytesC# System.Data.dll!System.Data.Common.DbCommand.System.Data.IDbCommand.ExecuteReader(System .Data.CommandBehavior behavior) + 0xb bytes System.Data.dll!System.Data.Common.DbDataAdapter.FillInternal(System.Data.DataSet dataset = {System.Data.DataSet}, System.Data.DataTable[] datatables = null, int startRecord = 0, int maxRecords = 0, string srcTable = "Table", System.Data.IDbCommand command = {MySql.Data.MySqlClient.MySqlCommand}, System.Data.CommandBehavior behavior) + 0x83 bytes System.Data.dll!System.Data.Common.DbDataAdapter.Fill(System.Data.DataSet dataSet, int startRecord, int maxRecords, string srcTable, System.Data.IDbCommand command, System.Data.CommandBehavior behavior) + 0x120 bytes System.Data.dll!System.Data.Common.DbDataAdapter.Fill(System.Data.DataSet dataSet) + 0x5f bytes (Bug #46213) * Conversion of MySQL `TINYINT(1)' to `boolean' failed. (Bug #46205, Bug #46359, Bug #41953) * When populating a MySQL database table in Visual Studio using the Table Editor, if a `VARCHAR(10)' column was changed to a `VARCHAR(20)' column an exception was generated: SystemArgumentException: DataGridViewComboBoxCell value is not valid. To replace this default dialog please handle the DataError Event. (Bug #46100) * The Entity Framework provider was not calling `DBSortExpression' correctly when the `Skip' and `Take' methods were used, such as in the following statement: TestModel.tblquarantine.OrderByDescending(q => q.MsgDate).Skip(100).Take(100).ToList(); This resulted in the data being unsorted. (Bug #45723) * The MySQL Connector/NET 6.0.4 installer failed with an error. The error message generated was: There is a problem with this Windows Installer package. A DLL required for this install to complete could not be run. Contact your support personnel or package vendor. When `OK' was clicked to acknowledge the error the installer exited. (Bug #45474) * Calling the Entity Framework `SaveChanges()' method of any MySQL ORM Entity with a column type `TIME', generated an error message: Unknown PrimitiveKind Time (Bug #45457) * Insert into two tables failed when using the Entity Framework. The exception generated was: The value given is not an instance of type 'Edm.Int32' (Bug #45077) * Errors occurred when using the Entity Framework with cultures that used a comma as the decimal separator. This was because the formatting for `SINGLE', `DOUBLE' and `DECIMAL' values was not handled correctly. (Bug #44455) * When attempting to connect to MySQL using the Compact Framework version of MySQL Connector/NET, an `IndexOutOfRangeException' exception was generated on trying to open the connection. (Bug #43736) * When reading data, such as with a `MySqlDataAdapter' on a `MySqlConnection', MySQL Connector/NET could potentially enter an infinite loop in `CompressedStream.ReadNextpacket()' if compression was enabled. (Bug #43678) * An error occurred when building MySQL Connector/NET from source code checked out from the public SVN repository. This happened on Linux using Mono and Nant. The Mono JIT compiler version was 1.2.6.0. The Nant version was 0.85. When an attempt was made to build (for example) the MySQL Connector/NET 5.2 branch using the command: $ nant -buildfile:Client.build The following error occurred: BUILD FAILED Error loading buildfile. Encoding name 'Windows-1252' not supported. Parameter name: name (Bug #42411) * MySQL Connector/NET CHM documentation stated that MySQL Server 3.23 was supported. (Bug #42110) * In the case of long network inactivity, especially when connection pooling was used, connections were sometimes dropped, for example, by firewalls. Note: The bugfix introduced a new `keepalive' parameter, which prevents disconnects by sending an empty TCP packet after a specified timeout. (Bug #40684) * Calling a Stored Procedure with an output parameter through MySQL Connector/NET resulted in a memory leak. Calling the same Stored Procedure without an output parameter did not result in a memory leak. (Bug #36027)  File: manual.info, Node: connector-net-news-6-1-0, Prev: connector-net-news-6-1-1, Up: changes-6.1.x D.4.4.7 Changes in MySQL Connector/NET 6.1.0 (15 July 2009 alpha) ................................................................. This is the first Alpha release of 6.1. *Functionality added or changed:* * Changed GUID type - The backend representation of a guid type has been changed to be CHAR(36). This is so you can use the server UUID() function to populate a GUID table. UUID generates a 36 character string. Developers of older applications can add `old guids=true' to the connection string and the old BINARY(16) type will be used instead. * Support for native output parameters - This is supported when connected to a server that supports native output parameters. This includes servers as of 5.5.3 and 6.0.8. * Session State Provider - This enables you to store the state of your website in a MySQL server. * Website Configuration Dialog - This is a new wizard that is activated by clicking a button on the toolbar at the top of the Visual Studio Solution Explorer. It works in conjunction with the ASP.Net administration pages, making it easier to activate and set advanced options for the different MySQL web providers included.  File: manual.info, Node: changes-6.0.x, Next: changes-5.3.x, Prev: changes-6.1.x, Up: connector-net-news D.4.5 Changes in MySQL Connector/NET Version 6.0.x -------------------------------------------------- * Menu: * connector-net-news-6-0-8:: Changes in MySQL Connector/NET 6.0.8 (Not yet released) * connector-net-news-6-0-7:: Changes in MySQL Connector/NET 6.0.7 (30 August 2010) * connector-net-news-6-0-6:: Changes in MySQL Connector/NET 6.0.6 (28 April 2010) * connector-net-news-6-0-5:: Changes in MySQL Connector/NET 6.0.5 (12 November 2009) * connector-net-news-6-0-4:: Changes in MySQL Connector/NET 6.0.4 (16 June 2009) * connector-net-news-6-0-3:: Changes in MySQL Connector/NET 6.0.3 (28 April 2009) * connector-net-news-6-0-2:: Changes in MySQL Connector/NET 6.0.2 (07 April 2009 beta) * connector-net-news-6-0-1:: Changes in MySQL Connector/NET 6.0.1 (02 April 2009 beta) * connector-net-news-6-0-0:: Changes in MySQL Connector/NET 6.0.0 (02 March 2009 alpha)  File: manual.info, Node: connector-net-news-6-0-8, Next: connector-net-news-6-0-7, Prev: changes-6.0.x, Up: changes-6.0.x D.4.5.1 Changes in MySQL Connector/NET 6.0.8 (Not yet released) ............................................................... Fixes bugs since 6.0.7. *Bugs fixed:* * `MysqlDataReader.GetSchemaTable' returned incorrect values and types. (Bug #59989, Bug #11776346) * All queries other than `INSERT' were executed individually instead of as a batch even though batching was enabled for the connection. (Bug #59616, Bug #11850286) * MySQL Connector/NET generated an exception when executing a query consisting of ';', for example: mycmd(";",mycon) mycmd.executenonquery() The exception generated was: System.IndexOutOfRangeException: Index was outside the bounds of the array. at MySql.Data.MySqlClient.MySqlCommand.TrimSemicolons(String sql) at MySql.Data.MySqlClient.MySqlCommand.ExecuteReader(CommandBehavior behavior) at MySql.Data.MySqlClient.MySqlCommand.ExecuteReader() at MySql.Data.MySqlClient.MySqlCommand.ExecuteNonQuery() (Bug #59537, Bug #11766433) * Setting `Membership.ApplicationName' had no effect. (Bug #59438, Bug #11770465) * `MembershipProvider' did not generate hashes correctly if the algorithm was keyed. The Key of the algorithm should have been set if the `HashAlgorithm' was `KeyedHashAlgorithm'. (Bug #58906) * Code introduced to fix bug #54863 proved problematic on .NET version 3.5 and above. (Bug #58853) * The `MySqlTokenizer' contained unnecessary `Substring' and `Trim' calls: string token = sql.Substring(startIndex, stopIndex - startIndex).Trim(); The variable `token' was not used anywhere in the code. (Bug #58757) * `MySqlCommand.ExecuteReader(CommandBehavior)' threw a `NullReferenceException' when being called with `CommandBehavior.CloseConnection', if the SQL statement contained a syntax error, or contained invalid data such as an invalid column name. (Bug #58652) * `ReadFieldLength()' returned incorrect value for `BIGINT' autoincrement columns. (Bug #58373) * MySQL Connector/NET did not support the `utf8mb4' character set. When attempting to connect to `utf8mb4' tables or columns, an exception `KeyNotFoundException' was generated. (Bug #58244) * A typed dataset did not get the table name. (Bug #57894, Bug #11764989) * Setting `MySqlCommand.CommandTimeout' to 0 had no effect. It should have resulted in an infinite timeout. (Bug #57265) * When performing a row-by-row update, only the first row was updated and all other rows were ignored. (Bug #57092) * Setting the `Default Command Timeout' connection string option had no effect. (Bug #56806) * When an output parameter was declared as type `MySqlDbType.Bit', it failed to return with the correct value. (Bug #56756) * Default values returned for text columns were not quoted. This meant that the `COLUMN_DEFAULT' field of the `GetSchema' columns collection did not return a valid SQL expression. (Bug #56509) * MySQL Connector/NET for .NET/Mono attempted to dynamically load the assembly `Mono.Posix.dll' when a Unix socket was used to connect to the server. This failed and the connector was not able to use a Unix socket unless the `Mono.Posix.dll' assembly was previously loaded by the program. (Bug #56410) * The ADO.NET Entity Data Model could not add stored procedures from MySQL Server 5.0.45 but worked fine using MySQL Server 5.1. (Bug #55349)  File: manual.info, Node: connector-net-news-6-0-7, Next: connector-net-news-6-0-6, Prev: connector-net-news-6-0-8, Up: changes-6.0.x D.4.5.2 Changes in MySQL Connector/NET 6.0.7 (30 August 2010) ............................................................. Fixes bugs since 6.0.6. *Bugs fixed:* * Attempting to read `Double.MinValue' from a `DOUBLE' column in MySQL table generated the following exception: System.OverflowException : Value was either too large or too small for a Double. --OverflowException at System.Number.ParseDouble(String value, NumberStyles options, NumberFormatInfo numfmt) at MySql.Data.Types.MySqlDouble.MySql.Data.Types.IMySqlValue.ReadValue(MySqlPacket packet, Int64 length, Boolean nullVal) at MySql.Data.MySqlClient.NativeDriver.ReadColumnValue(Int32 index, MySqlField field, IMySqlValue valObject) at MySql.Data.MySqlClient.ResultSet.ReadColumnData(Boolean outputParms) at MySql.Data.MySqlClient.ResultSet.NextRow(CommandBehavior behavior) at MySql.Data.MySqlClient.MySqlDataReader.Read() (Bug #55644) * `MySqlDataAdapter.Update()' generated concurrency violations for custom stored procedure driven update commands that used `UpdateRowSource.FirstReturnedRecord'. (Bug #54895) * Several calls to `datadapter.Update()' with intervening changes to `DataTable' resulted in `ConcurrencyException' exceptions being generated. (Bug #54863) * The `MySqlHelper' object did not have an overloaded version of the `ExecuteReader' method that accepted a `MySqlConnection' object. (Bug #54570) * If `MySqlDataAdapter' was used with an `INSERT' command where the `VALUES' clause contained an expression with parentheses in it, and set the `adapter.UpdateBatchSize' parameter to be greater than one, then the call to `adapter.Update' either generated an exception or failed to batch the commands, executing each insert individually. (Bug #54386) * The method `MySql.Data.Common.QueryNormalizer.CollapseValueList' generated an `ArgumentOutOfRangeException'. (Bug #54152, Bug #53865) * Garbage Collector disposal of a `MySqlConnection' object caused the following exception: System.IO.EndOfStreamException: Attempted to read past the end of the stream. MySql.Data.MySqlClient.MySqlStream.ReadFully(Stream stream, Byte[] buffer, Int32 offset, Int32 count) MySql.Data.MySqlClient.MySqlStream.LoadPacket() Outer Exception Reading from the stream has failed. ... (Bug #53457) * After a timeout exception, if an attempt was made to reuse a connection returned to the connection pool the following exception was generated: [MySqlException (0x80004005): There is already an open DataReader associated with this Connection which must be closed first.] MySql.Data.MySqlClient.MySqlCommand.CheckState() +278 MySql.Data.MySqlClient.MySqlCommand.ExecuteReader(CommandBehavior behavior) +43 MySql.Data.MySqlClient.MySqlCommand.ExecuteReader() +6 Controls.SimpleCommand.ExecuteReader(String SQL) in ...:323 Albums.GetImagesByAlbum(SimpleCommand Cmd, Int32 iAlbum, String Order, String Limit) in ...:13 Forecast.Page_Load(Object sender, EventArgs e) in ...:70 System.Web.UI.Control.OnLoad(EventArgs e) +99 System.Web.UI.Control.LoadRecursive() +50 System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +627 (Bug #53357) * Membership schema creation failed if the default schema collation was not Latin1. (Bug #53174) * EventLog was not disposed in the SessionState provider. (Bug #52550) * Stored procedure enumeration code generated an error if a procedure was used in a dataset that did not return any resultsets. (Bug #50671) * When an application was subjected to increased concurrent load, MySQL Connector/NET generated the following error when calling stored procedures: A DataTable named \'Procedure Parameters\' already belongs to this DataSet. (Bug #49118) * In the ADO.NET Entity Data Model Wizard, the time to update a model scaled abnormally as the number of entities increased. (Bug #48791, Bug #12596237) * The `INSERT' command was significantly slower with MySQL Connector/NET 6.x compared to 5.x, when compression was enabled. (Bug #48243) * When the connection string option `Connection Reset = True' was used, a connection reset used the previously used encoding for the subsequent authentication operation. This failed, for example, if UCS2 was used to read the last column before the reset. (Bug #47153) * Opening a connection in the Visual Studio Server Explorer and choosing to alter an existing routine required another authentication at the server. (Bug #44715) * When batching was used in `MySqlDataAdapter', a connection was not opened automatically in `MySqlDataAdapter.Update()'. This resulted in an `InvalidOperationException' exception being generated, with the message text `connection must be valid and open'. MySQL Connector/NET has been changed to behave more like SQL Server: if the connection is closed, it is opened for the duration of update operation. (Bug #38411) * Database name was emitted into typed datasets. This prevented users using the configured default database. (Bug #33870)  File: manual.info, Node: connector-net-news-6-0-6, Next: connector-net-news-6-0-5, Prev: connector-net-news-6-0-7, Up: changes-6.0.x D.4.5.3 Changes in MySQL Connector/NET 6.0.6 (28 April 2010) ............................................................ Fixes bugs since 6.0.5. *Functionality added or changed:* * Procedure cacheing had a problem whereby if you created a procedure, dropped it, and recreated it with a different number of parameters an exception was generated. MySQL Connector/NET has been changed so that if the procedure is recreated with a different number of parameters, it will still be recognized. (Bug #52562) * MySQL Connector/NET has been changed to include `MySqlDataReader.GetFieldType(string columnname)'. Further, `MySqlDataReader.GetOrdinal()' now includes the name of the column in the exception if the column is not found. (Bug #47467) *Bugs fixed:* * If using MySQL Server 5.0.x it was not possible to alter stored routines in Visual Studio. If the stored routine was clicked, and the context sensitive menu option, Alter Routine, selected, the following error was generated: Unable to load object with error: Object reference not set to an instance of an object (Bug #55170) * In MySQL Connector/NET, the `MySqlConnection.Abort()' method contained a `try...catch' construct, with an empty `catch' block. This meant that any exception generated at this point would not be caught. (Bug #52769) * If `FunctionsReturnString=true' was used in the connection string, the decimal separator (according to locale) was not interpreted. (Bug #52187) * In MySQL Connector/NET, the `LoadCharsetMap()' function of the `CharSetMap' class set the following incorrect mapping: mapping.Add("latin1", new CharacterSet("latin1", 1)); This meant that, for example, the Euro sign was not handled correctly. The correct mapping should have been: mapping.Add("latin1", new CharacterSet("windows-1252", 1)); This is because MySQL's `latin1' character set is the same as the `windows-cp1252' character set and it extends the official ISO 8859-1 or IANA latin1. (Bug #51927) * A non-terminated string in SQL threw a CLR exception rather than a syntax exception. (Bug #51788) * When calling `ExecuteNonQuery' on a command object, the following exception occurred: Index and length must refer to a location within the string. Parameter name: length (Bug #51610) * The method `Command.TrimSemicolons' used `StringBuilder', and therefore allocated memory for the query even if it did not need to be trimmed. This led to excessive memory consumption when executing a number of large queries. (Bug #51149) * `MySqlCommand.Parameters.Clear()' did not work. (Bug #50444) * When the `MySqlScript.execute()' method was called, the following exception was generated: InvalidOperationException : The CommandText property has not been properly initialized. (Bug #50344) * Binary Columns were not displayed in the Query Builder of Visual Studio. (Bug #50171) * When the `UpdateBatchSize' property was set to a value greater than 1, only the first row was applied to the database. (Bug #50123) * When using table per type inheritance and listing the contents of the parent table, the result of the query was a list of child objects, even though there was no related child record with the same parent Id. (Bug #49850) * `MySqlDataReader.GetUInt64' returned an incorrect value when reading a `BIGINT UNSIGNED' column containing a value greater than 2147483647. (Bug #49794) * A `FormatException' was generated when an empty string was returned from a stored function. (Bug #49642) * When adding a data set in Visual Studio 2008, the following error was generated: Relations couldn't be addded. Column 'REFERENCED_TABLE_CATALOG' does not belong to table. This was due to a 'REFERENCED_TABLE_CATALOG' column not being included in the foreign keys collection. (Bug #48974) * Attempting to execute a load data local infile on a file where the user did not have write permissions, or the file was open in an editor gave an access denied error. (Bug #48944) * The method `MySqlDataReader.GetSchemaTable()' returned 0 in the `NumericPrecision' field for decimal and newdecimal columns. (Bug #48171) * When trying to create stored procedures from an SQL script, a `MySqlException' was thrown when attempting to redefine the `DELIMITER': MySql.Data.MySqlClient.MySqlException was unhandled Message="You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'DELIMITER' at line 1" Source="MySql.Data" ErrorCode=-2147467259 Number=1064 StackTrace: a` MySql.Data.MySqlClient.MySqlStream.ReadPacket() a` MySql.Data.MySqlClient.NativeDriver.ReadResult(UInt64& affectedRows, Int64& lastInsertId) a` MySql.Data.MySqlClient.MySqlDataReader.GetResultSet() a` MySql.Data.MySqlClient.MySqlDataReader.NextResult() a` MySql.Data.MySqlClient.MySqlCommand.ExecuteReader(CommandBehavior behavior) a` MySql.Data.MySqlClient.MySqlCommand.ExecuteReader() a` MySql.Data.MySqlClient.MySqlCommand.ExecuteNonQuery() a` MySql.Data.MySqlClient.MySqlScript.Execute() Note: The `MySqlScript' class has been fixed to support the delimiter statement as it is found in SQL scripts. (Bug #46429) * Calling a User Defined Function using Entity SQL in the Entity Framework caused a `NullReferenceException'. (Bug #45277) * A connection string set in `web.config' could not be reused after Visual Studio 2008 Professional was shut down. It continued working for the existing controls, but did not work for new controls added. (Bug #41629)  File: manual.info, Node: connector-net-news-6-0-5, Next: connector-net-news-6-0-4, Prev: connector-net-news-6-0-6, Up: changes-6.0.x D.4.5.4 Changes in MySQL Connector/NET 6.0.5 (12 November 2009) ............................................................... This is a new release, fixing recently discovered bugs. *Bugs fixed:* * Cloning of `MySqlCommand' was not typesafe. To clone a `MySqlCommand' it was necessary to do: MySqlCommand clone = (MySqlCommand)((ICloneable)comm).Clone(); MySQL Connector/NET was changed so that it was possible to do: MySqlCommand clone = comm.Clone(); (Bug #48460) * If `MySqlConnection.GetSchema' was called for "Indexes" on a table named `b`a`d' as follows: DataTable schemaPrimaryKeys = connection.GetSchema( "Indexes", new string[] { null, schemaName, "b`a`d"}); Then the following exception was generated: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'a`d`' at line 1 (Bug #48101) * It was not possible to retrieve a value from a MySQL server table, if the value was larger than that supported by the .NET type `System.Decimal'. MySQL Connector/NET was changed to expose the `MySqlDecimal' type, along with the supporting method `GetMySqlDecimal'. (Bug #48100) * An entity model created from a schema containing a table with a column of type `UNSIGNED BIGINT' and a view of the table did not behave correctly. When an entity was created and mapped to the view, the column that was of type `UNSIGNED BIGINT' was displayed as `BIGINT'. (Bug #47872) * When loading the `MySQLClient-mono.sln' file included with the Connector/NET source into Mono Develop, the following error occurred: /home/tbedford/connector-net-src/6.1/MySQLClient-mono.sln(22): Unsupported or unrecognized project: '/home/tbedford/connector-net-src/6.1/Installer/Installer.wixproj' If the file was modified to remove this problem, then attempting to build the solution generated the following error: /home/tbedford/connector-net-src/6.1/MySql.Data/Provider/Source/Connection.cs(280,46): error CS0115: `MySql.Data.MySqlClient.MySqlConnection.DbProviderFactory' is marked as an override but no suitable property found to override (Bug #47048) * If an error occurred during connection to a MySQL Server, deserializing the error message from the packet buffer caused a `NullReferenceException' to be thrown. When the method `MySqlPacket::ReadString()' attempted to retrieve the error message, the following line of code threw the exception: string s = encoding.GetString(bits, (int)buffer.Position, end - (int)buffer.Position); This was due to the fact that the encoding field had not been initialized correctly. (Bug #46844) * In the `MySqlDataReader' class the `GetSByte' function returned a `byte' value instead of an `sbyte' value. (Bug #46620) * The MySQL Connector/NET Profile Provider, `MySql.Web.Profile.MySQLProfileProvider', generated an error when running on Mono. When an attempt was made to save a string in `Profile.Name' the string was not saved to the `my_aspnet_Profiles' table. If an attempt was made to force the save with `Profile.Save()' the following error was generated: Server Error in '/mono' Application -------------------------------------------------------------------------------- The requested feature is not implemented. Description: HTTP 500. Error processing request. Stack Trace: System.NotImplementedException: The requested feature is not implemented. at MySql.Data.MySqlClient.MySqlConnection.EnlistTransaction (System.Transactions.Transaction transaction) [0x00000] at MySql.Data.MySqlClient.MySqlConnection.Open () [0x00000] at MySql.Web.Profile.MySQLProfileProvider.SetPropertyValues (System.Configuration.SettingsContext context, System.Configuration.SettingsPropertyValueCollection collection) [0x00000] -------------------------------------------------------------------------------- Version information: Mono Version: 2.0.50727.1433; ASP.NET Version: 2.0.50727.1433 (Bug #46375) * An exception was generated when using `TIMESTAMP' columns with the Entity Framework. (Bug #46311) * MySQL Connector/NET sometimes hung, without generating an exception. This happened if a read from a stream failed returning a 0, causing the code in `LoadPacket()' to enter an infinite loop. (Bug #46308) * When using MySQL Connector/NET 6.0.4 and a MySQL Server 4.1 an exception was generated when trying to execute: connection.GetSchema("Columns", ...); The exception generated was: 'connection.GetSchema("Columns")' threw an exception of type 'System.ArgumentException'System.Data.DataTable {System.ArgumentException} base{"Input string was not in a correct format.Couldn't store <'Select'> in NUMERIC_PRECISION Column. Expected type is UInt64."}System.Exception {System.ArgumentException} (Bug #46270) * The MySQL Connector/NET method `StoredProcedure.GetParameters(string)' ignored the programmer's setting of the `UseProcedureBodies' option. This broke any application for which the application's parameter names did not match the parameter names in the Stored Procedure, resulting in an `ArgumentException' with the message `Parameter 'foo' not found in the collection.' and the following stack trace: MySql.Data.dll!MySql.Data.MySqlClient.MySqlParameterCollection.GetParameterFlexible(stri ng parameterName = "pStart", bool throwOnNotFound = true) Line 459C# MySql.Data.dll!MySql.Data.MySqlClient.StoredProcedure.Resolve() Line 157 + 0x25 bytesC# MySql.Data.dll!MySql.Data.MySqlClient.MySqlCommand.ExecuteReader(System.Data.CommandBeha vior behavior = SequentialAccess) Line 405 + 0xb bytesC# MySql.Data.dll!MySql.Data.MySqlClient.MySqlCommand.ExecuteDbDataReader(System.Data.Comma ndBehavior behavior = SequentialAccess) Line 884 + 0xb bytesC# System.Data.dll!System.Data.Common.DbCommand.System.Data.IDbCommand.ExecuteReader(System .Data.CommandBehavior behavior) + 0xb bytes System.Data.dll!System.Data.Common.DbDataAdapter.FillInternal(System.Data.DataSet dataset = {System.Data.DataSet}, System.Data.DataTable[] datatables = null, int startRecord = 0, int maxRecords = 0, string srcTable = "Table", System.Data.IDbCommand command = {MySql.Data.MySqlClient.MySqlCommand}, System.Data.CommandBehavior behavior) + 0x83 bytes System.Data.dll!System.Data.Common.DbDataAdapter.Fill(System.Data.DataSet dataSet, int startRecord, int maxRecords, string srcTable, System.Data.IDbCommand command, System.Data.CommandBehavior behavior) + 0x120 bytes System.Data.dll!System.Data.Common.DbDataAdapter.Fill(System.Data.DataSet dataSet) + 0x5f bytes (Bug #46213) * Conversion of MySQL `TINYINT(1)' to `boolean' failed. (Bug #46205, Bug #46359, Bug #41953) * When populating a MySQL database table in Visual Studio using the Table Editor, if a `VARCHAR(10)' column was changed to a `VARCHAR(20)' column an exception was generated: SystemArgumentException: DataGridViewComboBoxCell value is not valid. To replace this default dialog please handle the DataError Event. (Bug #46100) * In MySQL Connector/NET 6.0.4 using `GetProcData' generated an error because the `parameters' data table was only created if MySQL Server was at least version 6.0.6, or if the `UseProcedureBodies' connection string option was set to true. Also the `DeriveParameters' command generated a null reference exception. This was because the `parameters' data table, which was null, was used in a `for each' loop. (Bug #45952) * The Entity Framework provider was not calling `DBSortExpression' correctly when the `Skip' and `Take' methods were used, such as in the following statement: TestModel.tblquarantine.OrderByDescending(q => q.MsgDate).Skip(100).Take(100).ToList(); This resulted in the data being unsorted. (Bug #45723) * The `EscapeString' code carried out escaping by calling `string.Replace' multiple times. This resulted in a performance bottleneck, as for every line a new string was allocated and another was disposed of by the garbage collector. (Bug #45699) * Adding the `Allow Batch=False' option to the connection string caused MySQL Connector/NET to generate the error: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'SET character_set_results=NULL' at line 1 (Bug #45502) * The MySQL Connector/NET 6.0.4 installer failed with an error. The error message generated was: There is a problem with this Windows Installer package. A DLL required for this install to complete could not be run. Contact your support personnel or package vendor. When `OK' was clicked to acknowledge the error the installer exited. (Bug #45474) * A MySQL Connector/NET test program that connected to MySQL Server using the connection string option `compress=true' crashed, but only when running on Mono. The program worked as expected when running on Microsoft Windows. This was due to a bug in Mono. MySQL Connector/NET was modified to avoid using `WeakReferences' in the `Compressed' stream class, which was causing the crash. (Bug #45463) * Calling the Entity Framework `SaveChanges()' method of any MySQL ORM Entity with a column type `TIME', generated an error message: Unknown PrimitiveKind Time (Bug #45457) * Insert into two tables failed when using the Entity Framework. The exception generated was: The value given is not an instance of type 'Edm.Int32' (Bug #45077) * Input parameters were missing from Stored Procedures when using them with ADO.NET Data Entities. (Bug #44985) * Errors occurred when using the Entity Framework with cultures that used a comma as the decimal separator. This was because the formatting for `SINGLE', `DOUBLE' and `DECIMAL' values was not handled correctly. (Bug #44455) * When attempting to connect to MySQL using the Compact Framework version of MySQL Connector/NET, an `IndexOutOfRangeException' exception was generated on trying to open the connection. (Bug #43736) * When reading data, such as with a `MySqlDataAdapter' on a `MySqlConnection', MySQL Connector/NET could potentially enter an infinite loop in `CompressedStream.ReadNextpacket()' if compression was enabled. (Bug #43678) * An error occurred when building MySQL Connector/NET from source code checked out from the public SVN repository. This happened on Linux using Mono and Nant. The Mono JIT compiler version was 1.2.6.0. The Nant version was 0.85. When an attempt was made to build (for example) the MySQL Connector/NET 5.2 branch using the command: $ nant -buildfile:Client.build The following error occurred: BUILD FAILED Error loading buildfile. Encoding name 'Windows-1252' not supported. Parameter name: name (Bug #42411) * After a Reference to "C:\Program Files\MySQL\MySQL Connector Net 5.2.4\Compact Framework\MySql.Data.CF.dll" was added to a Windows Mobile 5.0 project, the project then failed to build, generating a Microsoft Visual C# compiler error. The error generated was: Error 2 The type 'System.Runtime.CompilerServices.CompilerGeneratedAttribute' has no constructors defined MysqlTest Error 3 Internal Compiler Error (0xc0000005 at address 5A7E3714): likely culprit is 'COMPILE'. (Bug #42261) * MySQL Connector/NET CHM documentation stated that MySQL Server 3.23 was supported. (Bug #42110) * In the case of long network inactivity, especially when connection pooling was used, connections were sometimes dropped, for example, by firewalls. Note: The bugfix introduced a new `keepalive' parameter, which prevents disconnects by sending an empty TCP packet after a specified timeout. (Bug #40684) * MySQL Connector/NET generated the following exception: System.NullReferenceException: Object reference not set to an instance of an object. bei MySql.Data.MySqlClient.MySqlCommand.TimeoutExpired(Object commandObject) bei System.Threading._TimerCallback.TimerCallback_Context(Object state) bei System.Threading.ExecutionContext.runTryCode(Object userData) bei System.Runtime.CompilerServices.RuntimeHelpers.ExecuteCodeWithGuaranteedCleanup(TryCode code, CleanupCode backoutCode, Object userData) bei System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state) bei System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state) bei System.Threading._TimerCallback.PerformTimerCallback(Object state) (Bug #40005) * Calling a Stored Procedure with an output parameter through MySQL Connector/NET resulted in a memory leak. Calling the same Stored Procedure without an output parameter did not result in a memory leak. (Bug #36027) * Using a `DataAdapter' with a linked `MySqlCommandBuilder' the following exception was thrown when trying to call `da.Update(DataRow[] rows)': Connection must be valid and open (Bug #34657)  File: manual.info, Node: connector-net-news-6-0-4, Next: connector-net-news-6-0-3, Prev: connector-net-news-6-0-5, Up: changes-6.0.x D.4.5.5 Changes in MySQL Connector/NET 6.0.4 (16 June 2009) ........................................................... This is the first post-GA release, fixing recently discovered bugs. *Bugs fixed:* * If a certain socket exception occurred when trying to establish a MySQL database connection, MySQL Connector/NET displayed an exception message that appeared to be unrelated to the underlying problem. This masked the problem and made diagnosing problems more difficult. For example, if, when establishing a database connection using TCP/IP, Windows on the local machine allocated an ephemeral port that conflicted with a socket address still in use, then Windows/.NET would throw a socket exception with the following error text: Only one usage of each socket address (protocol/network address/port) is normally permitted IP ADDRESS/PORT. However, MySQL Connector/NET masked this socket exception and displayed an exception with the following text: Unable to connect to any of the specified MySQL hosts. (Bug #45021) * A SQL query string containing an escaped backslash caused an exception to be generated: Index and length must refer to a location within the string. Parameter name: length at System.String.InternalSubStringWithChecks(Int32 startIndex, Int32 length, Boolean fAlwaysCopy) at MySql.Data.MySqlClient.MySqlTokenizer.NextParameter() at MySql.Data.MySqlClient.Statement.InternalBindParameters(String sql, MySqlParameterCollection parameters, MySqlPacket packet) at MySql.Data.MySqlClient.Statement.BindParameters() at MySql.Data.MySqlClient.PreparableStatement.Execute() at MySql.Data.MySqlClient.MySqlCommand.ExecuteReader(CommandBehavior be‎havior) at MySql.Data.MySqlClient.MySqlCommand.ExecuteNonQuery() (Bug #44960) * The Microsoft Visual Studio solution file `MySQL-VS2005.sln' was invalid. Several projects could not be loaded and thus it was not possible to build MySQL Connector/NET from source. (Bug #44822) * The Data Set editor generated an error when attempts were made to modify insert, update or delete commands: Error in WHERE clause near '@'. Unable to parse query text. (Bug #44512) * The DataReader in MySQL Connector/NET 6.0.3 considered a BINARY(16) field as a GUID with a length of 16. (Bug #44507) * When creating a new DataSet the following error was generated: Failed to open a connection to database. Cannot load type with name 'MySQL.Data.VisualStudio.StoredProcedureColumnEnumerator' (Bug #44460) * The MySQL Connector/NET MySQLRoleProvider reported that there were no roles, even when roles existed. (Bug #44414) * MySQL Connector/NET was missing the capability to validate the server's certificate when using encryption. This made it possible to conduct a man-in-the-middle attack against the connection, which defeated the security provided by SSL. (Bug #38700)  File: manual.info, Node: connector-net-news-6-0-3, Next: connector-net-news-6-0-2, Prev: connector-net-news-6-0-4, Up: changes-6.0.x D.4.5.6 Changes in MySQL Connector/NET 6.0.3 (28 April 2009) ............................................................ First GA release. *Functionality added or changed:* * The `MySqlTokenizer' failed to split fieldnames from values if they were not separated by a space. This also happened if the string contained certain characters. As a result `MySqlCommand.ExecuteNonQuery' raised an index out of range exception. The resulting errors are illustrated by the following examples. Note, the example statements do not have delimiting spaces around the `=' operator. INSERT INTO anytable SET Text='test--test'; The tokenizer incorrectly interpreted the value as containing a comment. UPDATE anytable SET Project='123-456',Text='Can you explain this ?',Duration=15 WHERE ID=4711;' A `MySqlException' was generated, as the `?' in the value was interpreted by the tokenizer as a parameter sign. The error message generated was: Fatal error encountered during command execution. EXCEPTION: MySqlException - Parameter '?'' must be defined. (Bug #44318) *Bugs fixed:* * `MySQL.Data' was not displayed as a Reference inside Microsoft Visual Studio 2008 Professional. When a new C# project was created in Microsoft Visual Studio 2008 Professional, `MySQL.Data' was not displayed when `References', `Add Reference' was selected. (Bug #44141) * Column types for `SchemaProvider' and `ISSchemaProvider' did not match. When the source code in `SchemaProvider.cs' and `ISSchemaProvider.cs' were compared it was apparent that they were not using the same column types. The base provider used SQL such as `SHOW CREATE TABLE', while `ISSchemaProvider' used the schema information tables. Column types used by the base class were `INT64' and the column types used by `ISSchemaProvider' were `UNSIGNED'. (Bug #44123)  File: manual.info, Node: connector-net-news-6-0-2, Next: connector-net-news-6-0-1, Prev: connector-net-news-6-0-3, Up: changes-6.0.x D.4.5.7 Changes in MySQL Connector/NET 6.0.2 (07 April 2009 beta) ................................................................. This is a new development release, fixing recently discovered bugs. *Bugs fixed:* * MySQL Connector/NET 6.0.1 did not load in Microsoft Visual Studio 2008 and Visual Studio 2005 Pro. The following error message was generated: .NET Framework Data Provider for MySQL: The data provider object factory service was not found. (Bug #44064)  File: manual.info, Node: connector-net-news-6-0-1, Next: connector-net-news-6-0-0, Prev: connector-net-news-6-0-2, Up: changes-6.0.x D.4.5.8 Changes in MySQL Connector/NET 6.0.1 (02 April 2009 beta) ................................................................. This is a new Beta development release, fixing recently discovered bugs. *Bugs fixed:* * An insert and update error was generated by the decimal data type in the Entity Framework, when a German collation was used. (Bug #43574) * Generating an Entity Data Model (EDM) schema with a table containing columns with data types `MEDIUMTEXT' and `LONGTEXT' generated a runtime error message `Max value too long or too short for Int32'. (Bug #43480)  File: manual.info, Node: connector-net-news-6-0-0, Prev: connector-net-news-6-0-1, Up: changes-6.0.x D.4.5.9 Changes in MySQL Connector/NET 6.0.0 (02 March 2009 alpha) .................................................................. This is a new Alpha development release. *Bugs fixed:* * A null reference exception was generated when `MySqlConnection.ClearPool(connection)' was called. (Bug #42801)  File: manual.info, Node: changes-5.3.x, Next: changes-5.2.x, Prev: changes-6.0.x, Up: connector-net-news D.4.6 Changes in MySQL Connector/NET Version 5.3.x -------------------------------------------------- * Menu: * connector-net-news-5-3-0:: Changes in MySQL Connector/NET 5.3.0 (Not yet released)  File: manual.info, Node: connector-net-news-5-3-0, Prev: changes-5.3.x, Up: changes-5.3.x D.4.6.1 Changes in MySQL Connector/NET 5.3.0 (Not yet released) ............................................................... *Bugs fixed:* * The Web Provider did not work at all on a remote host, and did not create a database when using `autogenerateschema="true"'. (Bug #39072) * The MySQL Connector/NET installer program ended prematurely without reporting the specific error. (Bug #39019) * When called with an incorrect password the MembershipProvider.GetPassword() method threw a MySQLException instead of a MembershipPasswordException . (Bug #38939) * Possible overflow in MySqlPacket.ReadLong(). (Bug #36997) * The TokenizeSql method was adding query overhead and causing high CPU utilization for larger queries. (Bug #36836)  File: manual.info, Node: changes-5.2.x, Next: changes-5.1.x, Prev: changes-5.3.x, Up: connector-net-news D.4.7 Changes in MySQL Connector/NET Version 5.2.x -------------------------------------------------- * Menu: * connector-net-news-5-2-8:: Changes in MySQL Connector/NET 5.2.8 (Not yet released) * connector-net-news-5-2-7:: Changes in MySQL Connector/NET 5.2.7 (15 July 2009) * connector-net-news-5-2-6:: Changes in MySQL Connector/NET 5.2.6 (28 April 2009) * connector-net-news-5-2-5:: Changes in MySQL Connector/NET 5.2.5 (19 November 2008) * connector-net-news-5-2-4:: Changes in MySQL Connector/NET 5.2.4 (13 November 2008) * connector-net-news-5-2-3:: Changes in MySQL Connector/NET 5.2.3 (19 August 2008) * connector-net-news-5-2-2:: Changes in MySQL Connector/NET 5.2.2 (12 May 2008) * connector-net-news-5-2-1:: Changes in MySQL Connector/NET 5.2.1 (27 February 2008) * connector-net-news-5-2-0:: Changes in MySQL Connector/NET 5.2.0 (11 February 2008)  File: manual.info, Node: connector-net-news-5-2-8, Next: connector-net-news-5-2-7, Prev: changes-5.2.x, Up: changes-5.2.x D.4.7.1 Changes in MySQL Connector/NET 5.2.8 (Not yet released) ............................................................... *Bugs fixed:* * If `MySqlConnection.GetSchema' was called for "Indexes" on a table named `b`a`d' as follows: DataTable schemaPrimaryKeys = connection.GetSchema( "Indexes", new string[] { null, schemaName, "b`a`d"}); Then the following exception was generated: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'a`d`' at line 1 (Bug #48101) * When the connection string option `Connection Reset = True' was used, a connection reset used the previously used encoding for the subsequent authentication operation. This failed, for example, if UCS2 was used to read the last column before the reset. (Bug #47153) * In the `MySqlDataReader' class the `GetSByte' function returned a `byte' value instead of an `sbyte' value. (Bug #46620) * When trying to create stored procedures from an SQL script, a `MySqlException' was thrown when attempting to redefine the `DELIMITER': MySql.Data.MySqlClient.MySqlException was unhandled Message="You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'DELIMITER' at line 1" Source="MySql.Data" ErrorCode=-2147467259 Number=1064 StackTrace: a` MySql.Data.MySqlClient.MySqlStream.ReadPacket() a` MySql.Data.MySqlClient.NativeDriver.ReadResult(UInt64& affectedRows, Int64& lastInsertId) a` MySql.Data.MySqlClient.MySqlDataReader.GetResultSet() a` MySql.Data.MySqlClient.MySqlDataReader.NextResult() a` MySql.Data.MySqlClient.MySqlCommand.ExecuteReader(CommandBehavior behavior) a` MySql.Data.MySqlClient.MySqlCommand.ExecuteReader() a` MySql.Data.MySqlClient.MySqlCommand.ExecuteNonQuery() a` MySql.Data.MySqlClient.MySqlScript.Execute() Note: The `MySqlScript' class has been fixed to support the delimiter statement as it is found in SQL scripts. (Bug #46429) * The MySQL Connector/NET Profile Provider, `MySql.Web.Profile.MySQLProfileProvider', generated an error when running on Mono. When an attempt was made to save a string in `Profile.Name' the string was not saved to the `my_aspnet_Profiles' table. If an attempt was made to force the save with `Profile.Save()' the following error was generated: Server Error in '/mono' Application -------------------------------------------------------------------------------- The requested feature is not implemented. Description: HTTP 500. Error processing request. Stack Trace: System.NotImplementedException: The requested feature is not implemented. at MySql.Data.MySqlClient.MySqlConnection.EnlistTransaction (System.Transactions.Transaction transaction) [0x00000] at MySql.Data.MySqlClient.MySqlConnection.Open () [0x00000] at MySql.Web.Profile.MySQLProfileProvider.SetPropertyValues (System.Configuration.SettingsContext context, System.Configuration.SettingsPropertyValueCollection collection) [0x00000] -------------------------------------------------------------------------------- Version information: Mono Version: 2.0.50727.1433; ASP.NET Version: 2.0.50727.1433 (Bug #46375) * When using MySQL Connector/NET 6.0.4 and a MySQL Server 4.1 an exception was generated when trying to execute: connection.GetSchema("Columns", ...); The exception generated was: 'connection.GetSchema("Columns")' threw an exception of type 'System.ArgumentException'System.Data.DataTable {System.ArgumentException} base{"Input string was not in a correct format.Couldn't store <'Select'> in NUMERIC_PRECISION Column. Expected type is UInt64."}System.Exception {System.ArgumentException} (Bug #46270) * The MySQL Connector/NET method `StoredProcedure.GetParameters(string)' ignored the programmer's setting of the `UseProcedureBodies' option. This broke any application for which the application's parameter names did not match the parameter names in the Stored Procedure, resulting in an `ArgumentException' with the message `Parameter 'foo' not found in the collection.' and the following stack trace: MySql.Data.dll!MySql.Data.MySqlClient.MySqlParameterCollection.GetParameterFlexible(stri ng parameterName = "pStart", bool throwOnNotFound = true) Line 459C# MySql.Data.dll!MySql.Data.MySqlClient.StoredProcedure.Resolve() Line 157 + 0x25 bytesC# MySql.Data.dll!MySql.Data.MySqlClient.MySqlCommand.ExecuteReader(System.Data.CommandBeha vior behavior = SequentialAccess) Line 405 + 0xb bytesC# MySql.Data.dll!MySql.Data.MySqlClient.MySqlCommand.ExecuteDbDataReader(System.Data.Comma ndBehavior behavior = SequentialAccess) Line 884 + 0xb bytesC# System.Data.dll!System.Data.Common.DbCommand.System.Data.IDbCommand.ExecuteReader(System .Data.CommandBehavior behavior) + 0xb bytes System.Data.dll!System.Data.Common.DbDataAdapter.FillInternal(System.Data.DataSet dataset = {System.Data.DataSet}, System.Data.DataTable[] datatables = null, int startRecord = 0, int maxRecords = 0, string srcTable = "Table", System.Data.IDbCommand command = {MySql.Data.MySqlClient.MySqlCommand}, System.Data.CommandBehavior behavior) + 0x83 bytes System.Data.dll!System.Data.Common.DbDataAdapter.Fill(System.Data.DataSet dataSet, int startRecord, int maxRecords, string srcTable, System.Data.IDbCommand command, System.Data.CommandBehavior behavior) + 0x120 bytes System.Data.dll!System.Data.Common.DbDataAdapter.Fill(System.Data.DataSet dataSet) + 0x5f bytes (Bug #46213) * Conversion of MySQL `TINYINT(1)' to `boolean' failed. (Bug #46205, Bug #46359, Bug #41953) * If the application slept for longer than the specified `net_write_timeout', and then resumed `Read' operations on a connection, then the application failed silently. (Bug #45978) * When reading data, such as with a `MySqlDataAdapter' on a `MySqlConnection', MySQL Connector/NET could potentially enter an infinite loop in `CompressedStream.ReadNextpacket()' if compression was enabled. (Bug #43678) * An error occurred when building MySQL Connector/NET from source code checked out from the public SVN repository. This happened on Linux using Mono and Nant. The Mono JIT compiler version was 1.2.6.0. The Nant version was 0.85. When an attempt was made to build (for example) the MySQL Connector/NET 5.2 branch using the command: $ nant -buildfile:Client.build The following error occurred: BUILD FAILED Error loading buildfile. Encoding name 'Windows-1252' not supported. Parameter name: name (Bug #42411) * MySQL Connector/NET CHM documentation stated that MySQL Server 3.23 was supported. (Bug #42110) * Using a `DataAdapter' with a linked `MySqlCommandBuilder' the following exception was thrown when trying to call `da.Update(DataRow[] rows)': Connection must be valid and open (Bug #34657)  File: manual.info, Node: connector-net-news-5-2-7, Next: connector-net-news-5-2-6, Prev: connector-net-news-5-2-8, Up: changes-5.2.x D.4.7.2 Changes in MySQL Connector/NET 5.2.7 (15 July 2009) ........................................................... *Bugs fixed:* * The `EscapeString' code carried out escaping by calling `string.Replace' multiple times. This resulted in a performance bottleneck, as for every line a new string was allocated and another was disposed of by the garbage collector. (Bug #45699) * A MySQL Connector/NET test program that connected to MySQL Server using the connection string option `compress=true' crashed, but only when running on Mono. The program worked as expected when running on Microsoft Windows. This was due to a bug in Mono. MySQL Connector/NET was modified to avoid using `WeakReferences' in the `Compressed' stream class, which was causing the crash. (Bug #45463) * If a certain socket exception occurred when trying to establish a MySQL database connection, MySQL Connector/NET displayed an exception message that appeared to be unrelated to the underlying problem. This masked the problem and made diagnosing problems more difficult. For example, if, when establishing a database connection using TCP/IP, Windows on the local machine allocated an ephemeral port that conflicted with a socket address still in use, then Windows/.NET would throw a socket exception with the following error text: Only one usage of each socket address (protocol/network address/port) is normally permitted IP ADDRESS/PORT. However, MySQL Connector/NET masked this socket exception and displayed an exception with the following text: Unable to connect to any of the specified MySQL hosts. (Bug #45021) * The Microsoft Visual Studio solution file `MySQL-VS2005.sln' was invalid. Several projects could not be loaded and thus it was not possible to build MySQL Connector/NET from source. (Bug #44822) * The MySQL Connector/NET MySQLRoleProvider reported that there were no roles, even when roles existed. (Bug #44414) * After a Reference to "C:\Program Files\MySQL\MySQL Connector Net 5.2.4\Compact Framework\MySql.Data.CF.dll" was added to a Windows Mobile 5.0 project, the project then failed to build, generating a Microsoft Visual C# compiler error. The error generated was: Error 2 The type 'System.Runtime.CompilerServices.CompilerGeneratedAttribute' has no constructors defined MysqlTest Error 3 Internal Compiler Error (0xc0000005 at address 5A7E3714): likely culprit is 'COMPILE'. (Bug #42261) * MySQL Connector/NET generated the following exception: System.NullReferenceException: Object reference not set to an instance of an object. bei MySql.Data.MySqlClient.MySqlCommand.TimeoutExpired(Object commandObject) bei System.Threading._TimerCallback.TimerCallback_Context(Object state) bei System.Threading.ExecutionContext.runTryCode(Object userData) bei System.Runtime.CompilerServices.RuntimeHelpers.ExecuteCodeWithGuaranteedCleanup(TryCode code, CleanupCode backoutCode, Object userData) bei System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state) bei System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state) bei System.Threading._TimerCallback.PerformTimerCallback(Object state) (Bug #40005) * When a TableAdapter was created on a DataSet, it was not possible to use a stored procedure with variables. The following error was generated: The method or operation is not implemented (Bug #39409)  File: manual.info, Node: connector-net-news-5-2-6, Next: connector-net-news-5-2-5, Prev: connector-net-news-5-2-7, Up: changes-5.2.x D.4.7.3 Changes in MySQL Connector/NET 5.2.6 (28 April 2009) ............................................................ *Functionality added or changed:* * A new connection string option has been added: `use affected rows'. When `true' the connection will report changed rows instead of found rows. (Bug #44194) *Bugs fixed:* * Calling `GetSchema()' on `Indexes' or `IndexColumns' failed where index or column names were restricted. In `SchemaProvider.cs', methods `GetIndexes()' and `GetIndexColumns()' passed their restrictions directly to `GetTables()'. This only worked if the restrictions were no more specific than `schemaName' and `tableName'. If `IndexName' was given, this was passed to `GetTables()' where it was treated as `TableType'. As a result no tables were returned, unless the index name happened to be `BASE TABLE' or `VIEW'. This meant that both methods failed to return any rows. (Bug #43991) * `GetSchema("MetaDataCollections")' should have returned a table with a column named `NumberOfRestrictions' not `NumberOfRestriction'. This can be confirmed by referencing the Microsoft Documentation (http://msdn.microsoft.com/en-us/library/system.data.common.dbmetadatacolumnnames.numberofrestrictions.aspx). (Bug #43990) * Requests sent to the MySQL Connector/NET role provider to remove a user from a role failed. The query log showed the query was correctly executed within a transaction which was immediately rolled back. The rollback was caused by a missing call to the `Complete' method of the transaction. (Bug #43553) * When using `MySqlBulkLoader.Load()', the text file is opened by `NativeDriver.SendFileToServer'. If it encountered a problem opening the file as a stream, an exception was generated and caught. An attempt to clean up resources was then made in the `finally{}' clause by calling `fs.Close()', but since the stream was never successfully opened, this was an attempt to execute a method of a null reference. (Bug #43332) * A null reference exception was generated when `MySqlConnection.ClearPool(connection)' was called. (Bug #42801) * `MySQLMembershipProvider.ValidateUser' only used the `userId' to validate. However, it should also use the `applicationId' to perform the validation correctly. The generated query was, for example: SELECT Password, PasswordKey, PasswordFormat, IsApproved, Islockedout FROM my_aspnet_Membership WHERE userId=13 Note that `applicationId' is not used. (Bug #42574) * There was an error in the `ProfileProvider' class in the `private ProfileInfoCollection GetProfiles()' function. The column of the final table was named `lastUpdatdDate' ('e' is missing) instead of the correct `lastUpdatedDate'. (Bug #41654) * The GetGuid() method of MySqlDataReader did not treat `BINARY(16)' column data as a GUID. When operating on such a column a `FormatException' exception was generated. (Bug #41452) * When ASP.NET membership was configured to not require password question and answer using `requiresQuestionAndAnswer="false"', a `SqlNullValueException' was generated when using `MembershipUser.ResetPassword()' to reset the user password. (Bug #41408) * If a `Stored Procedure' contained spaces in its parameter list, and was then called from MySQL Connector/NET, an exception was generated. However, the same `Stored Procedure' called from the MySQL Query Analyzer or the MySQL Client worked correctly. The exception generated was: Parameter '0' not found in the collection. (Bug #41034) * The `DATETIME' format contained an erroneous space. (Bug #41021) * When `MySql.Web.Profile.MySQLProfileProvider' was configured, it was not possible to assign a name other than the default name `MySQLProfileProvider'. If the name `SCC_MySQLProfileProvider' was assigned, an exception was generated when attempting to use `Page.Context.Profile['custom prop']'. The exception generated was: The profile default provider was not found. Note that the exception stated: 'the profile *default provider*...', even though a different name was explicitly requested. (Bug #40871) * When `ExecuteNonQuery' was called with a command type of `Stored Procedure' it worked for one user but resulted in a hang for another user with the same database permissions. However, if *Note `CALL': call. was used in the command text and `ExecuteNonQuery' was used with a command type of `Text', the call worked for both users. (Bug #40139)  File: manual.info, Node: connector-net-news-5-2-5, Next: connector-net-news-5-2-4, Prev: connector-net-news-5-2-6, Up: changes-5.2.x D.4.7.4 Changes in MySQL Connector/NET 5.2.5 (19 November 2008) ............................................................... *Bugs fixed:* * Visual Studio 2008 displayed the following error three times on start-up: "Package Load Failure Package 'MySql.Data.VisualStudio.MySqlDataProviderPackage, MySql.VisualStudio, Version=5.2.4, Culture=neutral, PublicKeyToken=null' has failed to load properly (GUID = {79A115C9-B133-4891-9E7B-242509DAD272}). Please contact the package vendor for assistance. Application restart is recommended, due to possible environment corruption. Would you like to disable loading the package in the future? You may use 'devenve/resetskippkgs' to re-enable package loading." (Bug #40726)  File: manual.info, Node: connector-net-news-5-2-4, Next: connector-net-news-5-2-3, Prev: connector-net-news-5-2-5, Up: changes-5.2.x D.4.7.5 Changes in MySQL Connector/NET 5.2.4 (13 November 2008) ............................................................... *Bugs fixed:* * `MySqlDataReader' did not feature a `GetSByte' method. (Bug #40571) * When working with stored procedures MySQL Connector/NET generated an exception `Unknown "table parameters" in information_schema'. (Bug #40382) * `GetDefaultCollation' and `GetMaxLength' were not thread safe. These functions called the database to get a set of parameters and cached them in two static dictionaries in the function `InitCollections'. However, if many threads called them they would try to insert the same keys in the collections resulting in duplicate key exceptions. (Bug #40231) * If connection pooling was not set explicitly in the connection string, MySQL Connector/NET added `;Pooling=False' to the end of the connection string when `MySqlCommand.ExecuteReader()' was called. If connection pooling was explicitly set in the connection string, when `MySqlConnection.Open()' was called it converted `Pooling=True' to `pooling=True'. If `MySqlCommand.ExecuteReader()' was subsequently called, it concatenated `;Pooling=False' to the end of the connection string. The resulting connection string was thus terminated with `pooling=True;Pooling=False'. This disabled connection pooling completely. (Bug #40091) * The connection string option `Functions Return String' did not set the correct encoding for the result string. Even though the connection string option `Functions Return String=true;' is set, the result of `SELECT DES_DECRYPT()' contained `??' instead of the correct national character symbols. (Bug #40076) * If, when using the MySqlTransaction transaction object, an exception was thrown, the transaction object was not disposed of and the transaction was not rolled back. (Bug #39817) * After the `ConnectionString' property was initialized using the public setter of DbConnectionStringBuilder, the GetConnectionString method of MySqlConnectionStringBuilder incorrectly returned `null' when `true' was assigned to the `includePass' parameter. (Bug #39728) * When using ProfileProvider, attempting to update a previously saved property failed. (Bug #39330) * Reading a negative time value greater than -01:00:00 returned the absolute value of the original time value. (Bug #39294) * Inserting a negative time value (negative `TimeSpan') into a `Time' column through the use of MySqlParameter caused MySqlException to be thrown. (Bug #39275) * When a data connection was created in the server explorer of Visual Studio 2008 Team, an error was generated when trying to expand stored procedures that had parameters. Also, if `TableAdapter' was right-clicked and then `Add', `Query', `Use Existing Stored Procedures' selected, if you then attempted to select a stored procedure, the window would close and no error message would be displayed. (Bug #39252) * The Web Provider did not work at all on a remote host, and did not create a database when using `autogenerateschema="true"'. (Bug #39072) * MySQL Connector/NET called hashed password methods not supported in Mono 2.0 Preview 2. (Bug #38895)  File: manual.info, Node: connector-net-news-5-2-3, Next: connector-net-news-5-2-2, Prev: connector-net-news-5-2-4, Up: changes-5.2.x D.4.7.6 Changes in MySQL Connector/NET 5.2.3 (19 August 2008) ............................................................. *Functionality added or changed:* * Error string was returned after a 28000 second `wait_timeout'. This has been changed to generate a `ConnectionState.Closed' event. (Bug #38119) * Changed how the procedure schema collection is retrieved. If `use procedure bodies=true' then the `mysql.proc' table is selected directly as this is up to 50 times faster than the current `information_schema' implementation. If `use procedure bodies=false', then the `information_schema' collection is queried. (Bug #36694) * String escaping functionality has been moved from the MySqlString class to the MySqlHelper class, where it can be accessed by the EscapeString method. (Bug #36205) *Bugs fixed:* * The GetOrdinal() method failed to return the ordinal if the column name string contained an accent. (Bug #38721) * MySQL Connector/NET uninstaller did not clean up all installed files. (Bug #38534) * There was a short circuit evaluation error in the MySqlCommand.CheckState() method. When the statement `connection == null' was true a NullReferenceException was thrown and not the expected InvalidOperationException. (Bug #38276) * The provider did not silently create the user if the user did not exist. (Bug #38243) * Executing a command that resulted in a fatal exception did not close the connection. (Bug #37991) * When a prepared insert query is run that contains an `UNSIGNED TINYINT' in the parameter list, the complete query and data that should be inserted is corrupted and no error is thrown. (Bug #37968) * In a .NET application MySQL Connector/NET modifies the connection string so that it contains several occurrences of the same option with different values. This is illustrated by the example that follows. The original connection string: host=localhost;database=test;uid=*****;pwd=*****; connect timeout=25; auto enlist=false;pooling=false; The connection string after closing MySqlDataReader: host=localhost;database=test;uid=*****;pwd=*****; connect timeout=25;auto enlist=false;pooling=false; Allow User Variables=True;Allow User Variables=False; Allow User Variables=True;Allow User Variables=False; (Bug #37955) * Unnecessary network traffic was generated for the normal case where the web provider schema was up to date. (Bug #37469) * MySqlReader.GetOrdinal() performance enhancements break existing functionality. (Bug #37239) * The `autogenerateschema' option produced tables with incorrect collations. (Bug #36444) * GetSchema did not work correctly when querying for a collection, if using a non-English locale. (Bug #35459) * When reading back a stored double or single value using the .NET provider, the value had less precision than the one stored. (Bug #33322) * Using the MySQL Visual Studio plugin and a MySQL 4.1 server, certain field types (*Note `ENUM': enum.) would not be identified correctly. Also, when looking for tables, the plugin would list all tables matching a wildcard pattern of the database name supplied in the connection string, instead of only tables within the specified database. (Bug #30603)  File: manual.info, Node: connector-net-news-5-2-2, Next: connector-net-news-5-2-1, Prev: connector-net-news-5-2-3, Up: changes-5.2.x D.4.7.7 Changes in MySQL Connector/NET 5.2.2 (12 May 2008) .......................................................... *Bugs fixed:* * Product documentation incorrectly stated '?' is the preferred parameter marker. (Bug #37349) * An incorrect value for a bit field would returned in a multi-row query if a preceding value for the field returned `NULL'. (Bug #36313) * Tables with `GEOMETRY' field types would return an unknown data type exception. (Bug #36081) * When using the `MySQLProfileProvider', setting profile details and then reading back saved data would result in the default values being returned instead of the updated values. (Bug #36000) * When creating a connection, setting the `ConnectionString' property of `MySqlConnection' to `NULL' would throw an exception. (Bug #35619) * The DbCommandBuilder.QuoteIdentifer method was not implemented. (Bug #35492) * When using encrypted passwords, the `GetPassword()' function would return the wrong string. (Bug #35336) * An error would be raised when calling `GetPassword()' with a `NULL' value. (Bug #35332) * When retrieving data where a field has been identified as containing a GUID value, the incorrect value would be returned when a previous row contained a `NULL' value for that field. (Bug #35041) * Using the `TableAdapter Wizard' would fail when generating commands that used stored procedures due to the change in supported parameter characters. (Bug #34941) * When creating a new stored procedures, the new parameter code which permits the use of the `@' symbol would interfere with the specification of a `DEFINER'. (Bug #34940) * When using `SqlDataSource' to open a connection, the connection would not automatically be closed when access had completed. (Bug #34460) * There was a high level of contention in the connection pooling code that could lead to delays when opening connections and submitting queries. The connection pooling code has been modified to try and limit the effects of the contention issue. (Bug #34001) * Using the `TableAdaptor' wizard in combination with a suitable *Note `SELECT': select. statement, only the associated *Note `INSERT': insert. statement would also be created, rather than the required *Note `DELETE': delete. and *Note `UPDATE': update. statements. (Bug #31338) * Fixed problem in datagrid code related to creating a new table. This problem may have been introduced with .NET 2.0 SP1. * Fixed profile provider that would throw an exception if you were updating a profile that already existed.  File: manual.info, Node: connector-net-news-5-2-1, Next: connector-net-news-5-2-0, Prev: connector-net-news-5-2-2, Up: changes-5.2.x D.4.7.8 Changes in MySQL Connector/NET 5.2.1 (27 February 2008) ............................................................... *Bugs fixed:* * When using the provider to generate or update users and passwords, the password checking algorithm would not validate the password strength or requirements correctly. (Bug #34792) * When executing statements that used stored procedures and functions, the new parameter code could fail to identify the correct parameter format. (Bug #34699) * The installer would fail to the DDEX provider binary if the Visual Studio 2005 component was not selected. The result would lead to MySQL Connector/NET not loading properly when using the interface to a MySQL server within Visual Studio. (Bug #34674) * A number of issues were identified in the case, connection and schema areas of the code for `MembershipProvider', `RoleProvider', `ProfileProvider'. (Bug #34495) * When using web providers, the MySQL Connector/NET would check the schema and cache the application id, even when the connection string had been set. The effect would be to break the membership provider list. (Bug #34451) * Attempting to use an isolation level other than the default with a transaction scope would use the default isolation level. (Bug #34448) * When altering a stored procedure within Visual Studio, the parameters to the procedure could be lost. (Bug #34359) * A race condition could occur within the procedure cache resulting the cache contents overflowing beyond the configured cache size. (Bug #34338) * Fixed problem with Visual Studio 2008 integration that caused pop-up menus on server explorer nodes to not function * The provider code has been updated to fix a number of outstanding issues.  File: manual.info, Node: connector-net-news-5-2-0, Prev: connector-net-news-5-2-1, Up: changes-5.2.x D.4.7.9 Changes in MySQL Connector/NET 5.2.0 (11 February 2008) ............................................................... *Functionality added or changed:* * Performing `GetValue()' on a field `TINYINT(1)' returned a *Note `BOOLEAN': numeric-types. While not a bug, this caused problems in software that expected an *Note `INT': numeric-types. to be returned. A new connection string option `Treat Tiny As Boolean' has been added with a default value of `true'. If set to `false' the provider will treat `TINYINT(1)' as *Note `INT': numeric-types. (Bug #34052) * Added support for `DbDataAdapter' `UpdateBatchSize'. Batching is fully supported including collapsing inserts down into the multi-value form if possible. * DDEX provider now works under Visual Studio 2008 beta 2. * Added ClearPool and ClearAllPools features. *Bugs fixed:* * Some speed improvements have been implemented in the `TokenizeSql' process used to identify elements of SQL statements. (Bug #34220) * When accessing tables from different databases within the same `TransactionScope', the same user/password combination would be used for each database connection. MySQL Connector/NET does not handle multiple connections within the same transaction scope. An error is now returned if you attempt this process, instead of using the incorrect authorization information. (Bug #34204) * The status of connections reported through the state change handler was not being updated correctly. (Bug #34082) * Incorporated some connection string cache optimizations sent to us by Maxim Mass. (Bug #34000) * In an open connection where the server had disconnected unexpectedly, the status information of the connection would not be updated properly. (Bug #33909) * Data cached from the connection string could return invalid information because the internal routines were not using case-sensitive semantics. This lead to updated connection string options not being recognized if they were of a different case than the existing cached values. (Bug #31433) * Column name metadata was not using the character set as defined within the connection string being used. (Bug #31185) * Memory usage could increase and decrease significantly when updating or inserting a large number of rows. (Bug #31090) * Commands executed from within the state change handeler would fail with a `NULL' exception. (Bug #30964) * When running a stored procedure multiple times on the same connection, the memory usage could increase indefinitely. (Bug #30116) * Using compression in the MySQL connection with MySQL Connector/NET would be slower than using native (uncompressed) communication. (Bug #27865) * The `MySqlDbType.Datetime' has been replaced with `MySqlDbType.DateTime'. The old format has been obsoleted. (Bug #26344)  File: manual.info, Node: changes-5.1.x, Next: changes-5.0.x, Prev: changes-5.2.x, Up: connector-net-news D.4.8 Changes in MySQL Connector/NET Version 5.1.x -------------------------------------------------- * Menu: * connector-net-news-5-1-8:: Changes in MySQL Connector/NET 5.1.8 (Not yet released) * connector-net-news-5-1-7:: Changes in MySQL Connector/NET 5.1.7 (21 August 2008) * connector-net-news-5-1-6:: Changes in MySQL Connector/NET 5.1.6 (12 May 2008) * connector-net-news-5-1-5:: Changes in MySQL Connector/NET 5.1.5 (Not yet released) * connector-net-news-5-1-4:: Changes in MySQL Connector/NET 5.1.4 (20 November 2007) * connector-net-news-5-1-3:: Changes in MySQL Connector/NET 5.1.3 (21 September 2007 beta) * connector-net-news-5-1-2:: Changes in MySQL Connector/NET 5.1.2 (18 June 2007) * connector-net-news-5-1-1:: Changes in MySQL Connector/NET 5.1.1 (23 May 2007) * connector-net-news-5-1-0:: Changes in MySQL Connector/NET 5.1.0 (01 May 2007)  File: manual.info, Node: connector-net-news-5-1-8, Next: connector-net-news-5-1-7, Prev: changes-5.1.x, Up: changes-5.1.x D.4.8.1 Changes in MySQL Connector/NET 5.1.8 (Not yet released) ............................................................... *Bugs fixed:* * Calling `GetSchema()' on `Indexes' or `IndexColumns' failed where index or column names were restricted. In `SchemaProvider.cs', methods `GetIndexes()' and `GetIndexColumns()' passed their restrictions directly to `GetTables()'. This only worked if the restrictions were no more specific than `schemaName' and `tableName'. If `IndexName' was given, this was passed to `GetTables()' where it was treated as `TableType'. As a result no tables were returned, unless the index name happened to be `BASE TABLE' or `VIEW'. This meant that both methods failed to return any rows. (Bug #43991) * The `DATETIME' format contained an erroneous space. (Bug #41021) * If connection pooling was not set explicitly in the connection string, MySQL Connector/NET added `;Pooling=False' to the end of the connection string when `MySqlCommand.ExecuteReader()' was called. If connection pooling was explicitly set in the connection string, when `MySqlConnection.Open()' was called it converted `Pooling=True' to `pooling=True'. If `MySqlCommand.ExecuteReader()' was subsequently called, it concatenated `;Pooling=False' to the end of the connection string. The resulting connection string was thus terminated with `pooling=True;Pooling=False'. This disabled connection pooling completely. (Bug #40091) * MySQL Connector/NET generated the following exception: System.NullReferenceException: Object reference not set to an instance of an object. bei MySql.Data.MySqlClient.MySqlCommand.TimeoutExpired(Object commandObject) bei System.Threading._TimerCallback.TimerCallback_Context(Object state) bei System.Threading.ExecutionContext.runTryCode(Object userData) bei System.Runtime.CompilerServices.RuntimeHelpers.ExecuteCodeWithGuaranteedCleanup(TryCode code, CleanupCode backoutCode, Object userData) bei System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state) bei System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state) bei System.Threading._TimerCallback.PerformTimerCallback(Object state) (Bug #40005) * If, when using the MySqlTransaction transaction object, an exception was thrown, the transaction object was not disposed of and the transaction was not rolled back. (Bug #39817) * When a prepared insert query is run that contains an `UNSIGNED TINYINT' in the parameter list, the complete query and data that should be inserted is corrupted and no error is thrown. (Bug #37968) * Calling `MySqlDataAdapter.FillSchema' on a `SELECT' statement that referred to a table that did not exist left the connection in a bad state. After this call, all `SELECT' statements returned an empty result set. If the `SELECT' statement referred to a table that did exist then everything worked as expected. (Bug #30518)  File: manual.info, Node: connector-net-news-5-1-7, Next: connector-net-news-5-1-6, Prev: connector-net-news-5-1-8, Up: changes-5.1.x D.4.8.2 Changes in MySQL Connector/NET 5.1.7 (21 August 2008) ............................................................. *Bugs fixed:* * There was a short circuit evaluation error in the MySqlCommand.CheckState() method. When the statement `connection == null' was true a NullReferenceException was thrown and not the expected InvalidOperationException. (Bug #38276) * Executing a command that resulted in a fatal exception did not close the connection. (Bug #37991) * In a .NET application MySQL Connector/NET modifies the connection string so that it contains several occurrences of the same option with different values. This is illustrated by the example that follows. The original connection string: host=localhost;database=test;uid=*****;pwd=*****; connect timeout=25; auto enlist=false;pooling=false; The connection string after closing MySqlDataReader: host=localhost;database=test;uid=*****;pwd=*****; connect timeout=25;auto enlist=false;pooling=false; Allow User Variables=True;Allow User Variables=False; Allow User Variables=True;Allow User Variables=False; (Bug #37955) * As MySqlDbType.DateTime is not available in `VB.Net' the warning `The datetime enum value is obsolete' was always shown during compilation. (Bug #37406) * An unknown `MySqlErrorCode' was encountered when opening a connection with an incorrect password. (Bug #37398) * Documentation incorrectly stated that `the DataColumn class in .NET 1.0 and 1.1 does not permit columns with type of UInt16, UInt32, or UInt64 to be autoincrement columns'. (Bug #37350) * SemaphoreFullException is generated when application is closed. (Bug #36688) * GetSchema did not work correctly when querying for a collection, if using a non-English locale. (Bug #35459) * When reading back a stored double or single value using the .NET provider, the value had less precision than the one stored. (Bug #33322) * Using the MySQL Visual Studio plugin and a MySQL 4.1 server, certain field types (*Note `ENUM': enum.) would not be identified correctly. Also, when looking for tables, the plugin would list all tables matching a wildcard pattern of the database name supplied in the connection string, instead of only tables within the specified database. (Bug #30603)  File: manual.info, Node: connector-net-news-5-1-6, Next: connector-net-news-5-1-5, Prev: connector-net-news-5-1-7, Up: changes-5.1.x D.4.8.3 Changes in MySQL Connector/NET 5.1.6 (12 May 2008) .......................................................... *Bugs fixed:* * When creating a connection pool, specifying an invalid IP address will cause the entire application to crash, instead of providing an exception. (Bug #36432) * An incorrect value for a bit field would returned in a multi-row query if a preceding value for the field returned `NULL'. (Bug #36313) * The `MembershipProvider' will raise an exception when the connection string is configured with `enablePasswordRetrival = true' and `RequireQuestionAndAnswer = false'. (Bug #36159) * When calling `GetNumberOfUsersOnline' an exception is raised on the submitted query due to a missing parameter. (Bug #36157) * Tables with `GEOMETRY' field types would return an unknown data type exception. (Bug #36081) * When creating a connection, setting the `ConnectionString' property of `MySqlConnection' to `NULL' would throw an exception. (Bug #35619) * The DbCommandBuilder.QuoteIdentifer method was not implemented. (Bug #35492) * When using `SqlDataSource' to open a connection, the connection would not automatically be closed when access had completed. (Bug #34460) * Attempting to use an isolation level other than the default with a transaction scope would use the default isolation level. (Bug #34448) * When altering a stored procedure within Visual Studio, the parameters to the procedure could be lost. (Bug #34359) * A race condition could occur within the procedure cache resulting the cache contents overflowing beyond the configured cache size. (Bug #34338) * Using the `TableAdaptor' wizard in combination with a suitable *Note `SELECT': select. statement, only the associated *Note `INSERT': insert. statement would also be created, rather than the required *Note `DELETE': delete. and *Note `UPDATE': update. statements. (Bug #31338)  File: manual.info, Node: connector-net-news-5-1-5, Next: connector-net-news-5-1-4, Prev: connector-net-news-5-1-6, Up: changes-5.1.x D.4.8.4 Changes in MySQL Connector/NET 5.1.5 (Not yet released) ............................................................... *Functionality added or changed:* * Performing `GetValue()' on a field `TINYINT(1)' returned a *Note `BOOLEAN': numeric-types. While not a bug, this caused problems in software that expected an *Note `INT': numeric-types. to be returned. A new connection string option `Treat Tiny As Boolean' has been added with a default value of `true'. If set to `false' the provider will treat `TINYINT(1)' as *Note `INT': numeric-types. (Bug #34052) *Bugs fixed:* * Some speed improvements have been implemented in the `TokenizeSql' process used to identify elements of SQL statements. (Bug #34220) * When accessing tables from different databases within the same `TransactionScope', the same user/password combination would be used for each database connection. MySQL Connector/NET does not handle multiple connections within the same transaction scope. An error is now returned if you attempt this process, instead of using the incorrect authorization information. (Bug #34204) * The status of connections reported through the state change handler was not being updated correctly. (Bug #34082) * Incorporated some connection string cache optimizations sent to us by Maxim Mass. (Bug #34000) * In an open connection where the server had disconnected unexpectedly, the status information of the connection would not be updated properly. (Bug #33909) * MySQL Connector/NET would fail to compile properly with `nant'. (Bug #33508) * Problem with membership provider would mean that `FindUserByEmail' would fail with a `MySqlException' because it was trying to add a second parameter with the same name as the first. (Bug #33347) * Using compression in the MySQL connection with MySQL Connector/NET would be slower than using native (uncompressed) communication. (Bug #27865)  File: manual.info, Node: connector-net-news-5-1-4, Next: connector-net-news-5-1-3, Prev: connector-net-news-5-1-5, Up: changes-5.1.x D.4.8.5 Changes in MySQL Connector/NET 5.1.4 (20 November 2007) ............................................................... *Bugs fixed:* * Setting the size of a string parameter after the value could cause an exception. (Bug #32094) * Creation of parameter objects with noninput direction using a constructor would fail. This was cause by some old legacy code preventing their use. (Bug #32093) * A date string could be returned incorrectly by `MySqlDateTime.ToString()' when the date returned by MySQL was `0000-00-00 00:00:00'. (Bug #32010) * A syntax error in a set of batch statements could leave the data adapter in a state that appears hung. (Bug #31930) * Installing over a failed uninstall of a previous version could result in multiple clients being registered in the `machine.config'. This would prevent certain aspects of the MySQL connection within Visual Studio to work properly. (Bug #31731) * MySQL Connector/NET would incorrectly report success when enlisting in a distributed transaction, although distributed transactions are not supported. (Bug #31703) * Data cached from the connection string could return invalid information because the internal routines were not using case-sensitive semantics. This lead to updated connection string options not being recognized if they were of a different case than the existing cached values. (Bug #31433) * Trying to use a connection that was not open could return an ambiguous and misleading error message. (Bug #31262) * Column name metadata was not using the character set as defined within the connection string being used. (Bug #31185) * Memory usage could increase and decrease significantly when updating or inserting a large number of rows. (Bug #31090) * Commands executed from within the state change handeler would fail with a `NULL' exception. (Bug #30964) * Extracting data through XML functions within a query returns the data as `System.Byte[]'. This was due to MySQL Connector/NET incorrectly identifying *Note `BLOB': blob. fields as binary, rather than text. (Bug #30233) * When running a stored procedure multiple times on the same connection, the memory usage could increase indefinitely. (Bug #30116) * Column types with only 1-bit (such as *Note `BOOLEAN': numeric-types. and `TINYINT(1)' were not returned as boolean fields. (Bug #27959) * When accessing certain statements, the command would timeout before the command completed. Because this cannot always be controlled through the individual command timeout options, a `default command timeout' has been added to the connection string options. (Bug #27958) * The server error code was not updated in the `Data[]' hash, which prevented `DbProviderFactory' users from accessing the server error code. (Bug #27436) * The `MySqlDbType.Datetime' has been replaced with `MySqlDbType.DateTime'. The old format has been obsoleted. (Bug #26344) * Changing the connection string of a connection to one that changes the parameter marker after the connection had been assigned to a command but before the connection is opened could cause parameters to not be found. (Bug #13991)  File: manual.info, Node: connector-net-news-5-1-3, Next: connector-net-news-5-1-2, Prev: connector-net-news-5-1-4, Up: changes-5.1.x D.4.8.6 Changes in MySQL Connector/NET 5.1.3 (21 September 2007 beta) ..................................................................... This is a new Beta development release, fixing recently discovered bugs. *Bugs fixed:* * An incorrect `ConstraintException' could be raised on an *Note `INSERT': insert. when adding rows to a table with a multiple-column unique key index. (Bug #30204) * A *Note `DATE': datetime. field would be updated with a date/time value, causing a `MySqlDataAdapter.Update()' exception. (Bug #30077) * The Saudi Hijri calendar was not supported. (Bug #29931) * Calling *Note `SHOW CREATE PROCEDURE': show-create-procedure. for routines with a hyphen in the catalog name produced a syntax error. (Bug #29526) * Connecting to a MySQL server earlier than version 4.1 would raise a `NullException'. (Bug #29476) * The availability of a MySQL server would not be reset when using pooled connections (`pooling=true'). This would lead to the server being reported as unavailable, even if the server become available while the application was still running. (Bug #29409) * A `FormatException' error would be raised if a parameter had not been found, instead of `Resources.ParameterMustBeDefined'. (Bug #29312) * An exception would be thrown when using the Manage Role functionality within the web administrator to assign a role to a user. (Bug #29236) * Using the membership/role providers when `validationKey' or `decryptionKey' parameters are set to `AutoGenerate', an exception would be raised when accessing the corresponding values. (Bug #29235) * Certain operations would not check the `UsageAdvisor' setting, causing log messages from the Usage Advisor even when it was disabled. (Bug #29124) * Using the same connection string multiple times would result in `Database=DBNAME' appearing multiple times in the resulting string. (Bug #29123) * _Visual Studio Plugin_: Adding a new query based on a stored procedure that uses the *Note `SELECT': select. statement would terminate the query/TableAdapter wizard. (Bug #29098) * Using `TransactionScope' would cause an `InvalidOperationException'. (Bug #28709)  File: manual.info, Node: connector-net-news-5-1-2, Next: connector-net-news-5-1-1, Prev: connector-net-news-5-1-3, Up: changes-5.1.x D.4.8.7 Changes in MySQL Connector/NET 5.1.2 (18 June 2007) ........................................................... This is a new Beta development release, fixing recently discovered bugs. *Bugs fixed:* * Log messages would be truncated to 300 bytes. (Bug #28706) * Creating a user would fail due to the application name being set incorrectly. (Bug #28648) * _Visual Studio Plugin_: Adding a new query based on a stored procedure that used a *Note `UPDATE': update, *Note `INSERT': insert. or *Note `DELETE': delete. statement would terminate the query/TableAdapter wizard. (Bug #28536) * _Visual Studio Plugin_: Query Builder would fail to show *Note `TINYTEXT': blob. columns, and any columns listed after a *Note `TINYTEXT': blob. column correctly. (Bug #28437) * Accessing the results from a large query when using data compression in the connection would fail to return all the data. (Bug #28204) * _Visual Studio Plugin_: Update commands would not be generated correctly when using the TableAdapter wizard. (Bug #26347)  File: manual.info, Node: connector-net-news-5-1-1, Next: connector-net-news-5-1-0, Prev: connector-net-news-5-1-2, Up: changes-5.1.x D.4.8.8 Changes in MySQL Connector/NET 5.1.1 (23 May 2007) .......................................................... *Bugs fixed:* * Running the statement *Note `SHOW PROCESSLIST': show-processlist. would return columns as byte arrays instead of native columns. (Bug #28448) * Installation of the MySQL Connector/NET on Windows would fail if VisualStudio had not already been installed. (Bug #28260) * MySQL Connector/NET would look for the wrong table when executing `User.IsRole().' (Bug #28251) * Building a connection string within a tight loop would show slow performance. (Bug #28167) * The `UNSIGNED' flag for parameters in a stored procedure would be ignored when using `MySqlCommandBuilder' to obtain the parameter information. (Bug #27679) * Using `MySQLDataAdapter.FillSchema()' on a stored procedure would raise an exception: `Invalid attempt to access a field before calling Read()'. (Bug #27668) * *Note `DATETIME': datetime. fields from versions of MySQL bgefore 4.1 would be incorrectly parsed, resulting in a exception. (Bug #23342) * Fixed password property on `MySqlConnectionStringBuilder' to use `PasswordPropertyText' attribute. This causes dots to show instead of actual password text.  File: manual.info, Node: connector-net-news-5-1-0, Prev: connector-net-news-5-1-1, Up: changes-5.1.x D.4.8.9 Changes in MySQL Connector/NET 5.1.0 (01 May 2007) .......................................................... *Functionality added or changed:* * Now compiles for .NET CF 2.0. * Rewrote stored procedure parsing code using a new SQL tokenizer. Really nasty procedures including nested comments are now supported. * GetSchema will now report objects relative to the currently selected database. What this means is that passing in null as a database restriction will report objects on the currently selected database only. * Added Membership and Role provider contributed by Sean Wright (thanks!).  File: manual.info, Node: changes-5.0.x, Next: changes-1.0.x, Prev: changes-5.1.x, Up: connector-net-news D.4.9 Changes in MySQL Connector/NET Version 5.0.x -------------------------------------------------- * Menu: * connector-net-news-5-0-10:: Changes in MySQL Connector/NET 5.0.10 (Not yet released) * connector-net-news-5-0-9:: Changes in MySQL Connector/NET 5.0.9 (Not yet released) * connector-net-news-5-0-8:: Changes in MySQL Connector/NET 5.0.8 (21 August 2007) * connector-net-news-5-0-7:: Changes in MySQL Connector/NET 5.0.7 (18 May 2007) * connector-net-news-5-0-6:: Changes in MySQL Connector/NET 5.0.6 (22 March 2007) * connector-net-news-5-0-5:: Changes in MySQL Connector/NET 5.0.5 (07 March 2007) * connector-net-news-5-0-4:: Changes in MySQL Connector/NET 5.0.4 (Not released) * connector-net-news-5-0-3:: Changes in MySQL Connector/NET 5.0.3 (05 January 2007) * connector-net-news-5-0-2:: Changes in MySQL Connector/NET 5.0.2 (06 November 2006) * connector-net-news-5-0-1:: Changes in MySQL Connector/NET 5.0.1 (01 October 2006) * connector-net-news-5-0-0:: Changes in MySQL Connector/NET 5.0.0 (08 August 2006)  File: manual.info, Node: connector-net-news-5-0-10, Next: connector-net-news-5-0-9, Prev: changes-5.0.x, Up: changes-5.0.x D.4.9.1 Changes in MySQL Connector/NET 5.0.10 (Not yet released) ................................................................ *Bugs fixed:* * If, when using the MySqlTransaction transaction object, an exception was thrown, the transaction object was not disposed of and the transaction was not rolled back. (Bug #39817) * Executing a command that resulted in a fatal exception did not close the connection. (Bug #37991) * When a prepared insert query is run that contains an `UNSIGNED TINYINT' in the parameter list, the complete query and data that should be inserted is corrupted and no error is thrown. (Bug #37968) * In a .NET application MySQL Connector/NET modifies the connection string so that it contains several occurrences of the same option with different values. This is illustrated by the example that follows. The original connection string: host=localhost;database=test;uid=*****;pwd=*****; connect timeout=25; auto enlist=false;pooling=false; The connection string after closing MySqlDataReader: host=localhost;database=test;uid=*****;pwd=*****; connect timeout=25;auto enlist=false;pooling=false; Allow User Variables=True;Allow User Variables=False; Allow User Variables=True;Allow User Variables=False; (Bug #37955) * When creating a connection pool, specifying an invalid IP address will cause the entire application to crash, instead of providing an exception. (Bug #36432) * GetSchema did not work correctly when querying for a collection, if using a non-English locale. (Bug #35459) * When reading back a stored double or single value using the .NET provider, the value had less precision than the one stored. (Bug #33322)  File: manual.info, Node: connector-net-news-5-0-9, Next: connector-net-news-5-0-8, Prev: connector-net-news-5-0-10, Up: changes-5.0.x D.4.9.2 Changes in MySQL Connector/NET 5.0.9 (Not yet released) ............................................................... *Bugs fixed:* * The DbCommandBuilder.QuoteIdentifer method was not implemented. (Bug #35492) * Setting the size of a string parameter after the value could cause an exception. (Bug #32094) * Creation of parameter objects with noninput direction using a constructor would fail. This was cause by some old legacy code preventing their use. (Bug #32093) * A date string could be returned incorrectly by `MySqlDateTime.ToString()' when the date returned by MySQL was `0000-00-00 00:00:00'. (Bug #32010) * A syntax error in a set of batch statements could leave the data adapter in a state that appears hung. (Bug #31930) * Installing over a failed uninstall of a previous version could result in multiple clients being registered in the `machine.config'. This would prevent certain aspects of the MySQL connection within Visual Studio to work properly. (Bug #31731) * Data cached from the connection string could return invalid information because the internal routines were not using case-sensitive semantics. This lead to updated connection string options not being recognized if they were of a different case than the existing cached values. (Bug #31433) * Column name metadata was not using the character set as defined within the connection string being used. (Bug #31185) * Memory usage could increase and decrease significantly when updating or inserting a large number of rows. (Bug #31090) * Commands executed from within the state change handeler would fail with a `NULL' exception. (Bug #30964) * When running a stored procedure multiple times on the same connection, the memory usage could increase indefinitely. (Bug #30116) * The server error code was not updated in the `Data[]' hash, which prevented `DbProviderFactory' users from accessing the server error code. (Bug #27436) * Changing the connection string of a connection to one that changes the parameter marker after the connection had been assigned to a command but before the connection is opened could cause parameters to not be found. (Bug #13991)  File: manual.info, Node: connector-net-news-5-0-8, Next: connector-net-news-5-0-7, Prev: connector-net-news-5-0-9, Up: changes-5.0.x D.4.9.3 Changes in MySQL Connector/NET 5.0.8 (21 August 2007) ............................................................. *Note*: This version introduces a new installer technology. *Bugs fixed:* * Extracting data through XML functions within a query returns the data as `System.Byte[]'. This was due to MySQL Connector/NET incorrectly identifying *Note `BLOB': blob. fields as binary, rather than text. (Bug #30233) * An incorrect `ConstraintException' could be raised on an *Note `INSERT': insert. when adding rows to a table with a multiple-column unique key index. (Bug #30204) * A *Note `DATE': datetime. field would be updated with a date/time value, causing a `MySqlDataAdapter.Update()' exception. (Bug #30077) * Fixed bug where MySQL Connector/NET was hand building some date time patterns rather than using the patterns provided under CultureInfo. This caused problems with some calendars that do not support the same ranges as Gregorian.. (Bug #29931) * Calling *Note `SHOW CREATE PROCEDURE': show-create-procedure. for routines with a hyphen in the catalog name produced a syntax error. (Bug #29526) * The availability of a MySQL server would not be reset when using pooled connections (`pooling=true'). This would lead to the server being reported as unavailable, even if the server become available while the application was still running. (Bug #29409) * A `FormatException' error would be raised if a parameter had not been found, instead of `Resources.ParameterMustBeDefined'. (Bug #29312) * Certain operations would not check the `UsageAdvisor' setting, causing log messages from the Usage Advisor even when it was disabled. (Bug #29124) * Using the same connection string multiple times would result in `Database=DBNAME' appearing multiple times in the resulting string. (Bug #29123) * Log messages would be truncated to 300 bytes. (Bug #28706) * Accessing the results from a large query when using data compression in the connection will fail to return all the data. (Bug #28204) * Fixed problem where `MySqlConnection.BeginTransaction' checked the drivers status var before checking if the connection was open. The result was that the driver could report an invalid condition on a previously opened connection. * Fixed problem where we were not closing prepared statement handles when commands are disposed. This could lead to using up all prepared statement handles on the server. * Fixed the database schema collection so that it works on servers that are not properly respecting the `lower_case_table_names' setting. * Fixed problem where any attempt to not read all the records returned from a select where each row of the select is greater than 1024 bytes would hang the driver. * Fixed problem where a command timing out just after it actually finished would cause an exception to be thrown on the command timeout thread which would then be seen as an unhandled exception. * Fixed some serious issues with command timeout and cancel that could present as exceptions about thread ownership. The issue was that not all queries cancel the same. Some produce resultsets while others don't. ExecuteReader had to be changed to check for this.  File: manual.info, Node: connector-net-news-5-0-7, Next: connector-net-news-5-0-6, Prev: connector-net-news-5-0-8, Up: changes-5.0.x D.4.9.4 Changes in MySQL Connector/NET 5.0.7 (18 May 2007) .......................................................... *Bugs fixed:* * Running the statement *Note `SHOW PROCESSLIST': show-processlist. would return columns as byte arrays instead of native columns. (Bug #28448) * Building a connection string within a tight loop would show slow performance. (Bug #28167) * Using logging (with the `logging=true' parameter to the connection string) would not generate a log file. (Bug #27765) * The `UNSIGNED' flag for parameters in a stored procedure would be ignored when using `MySqlCommandBuilder' to obtain the parameter information. (Bug #27679) * Using `MySQLDataAdapter.FillSchema()' on a stored procedure would raise an exception: `Invalid attempt to access a field before calling Read()'. (Bug #27668) * If you close an open connection with an active transaction, the transaction is not automatically rolled back. (Bug #27289) * When cloning an open `MySqlClient.MySqlConnection' with the `Persist Security Info=False' option set, the cloned connection is not usable because the security information has not been cloned. (Bug #27269) * Enlisting a null transaction would affect the current connection object, such that further enlistment operations to the transaction are not possible. (Bug #26754) * Attempting to change the `Connection Protocol' property within a `PropertyGrid' control would raise an exception. (Bug #26472) * The `characterset' property would not be identified during a connection (also affected Visual Studion Plugin). (Bug #26147, Bug #27240) * The `CreateFormat' column of the `DataTypes' collection did not contain a format specification for creating a new column type. (Bug #25947) * *Note `DATETIME': datetime. fields from versions of MySQL bgefore 4.1 would be incorrectly parsed, resulting in a exception. (Bug #23342)  File: manual.info, Node: connector-net-news-5-0-6, Next: connector-net-news-5-0-5, Prev: connector-net-news-5-0-7, Up: changes-5.0.x D.4.9.5 Changes in MySQL Connector/NET 5.0.6 (22 March 2007) ............................................................ *Bugs fixed:* * Publisher listed in "Add/Remove Programs" is not consistent with other MySQL products. (Bug #27253) * `DESCRIBE ....' SQL statement returns byte arrays rather than data on MySQL versions older than 4.1.15. (Bug #27221) * `cmd.Parameters.RemoveAt("Id")' will cause an error if the last item is requested. (Bug #27187) * `MySqlParameterCollection' and parameters added with `Insert' method can not be retrieved later using `ParameterName'. (Bug #27135) * Exception thrown when using large values in `UInt64' parameters. (Bug #27093) * MySQL Visual Studio Plugin 1.1.2 does not work with MySQL Connector/NET 5.0.5. (Bug #26960)  File: manual.info, Node: connector-net-news-5-0-5, Next: connector-net-news-5-0-4, Prev: connector-net-news-5-0-6, Up: changes-5.0.x D.4.9.6 Changes in MySQL Connector/NET 5.0.5 (07 March 2007) ............................................................ *Functionality added or changed:* * Reverted behavior that required parameter names to start with the parameter marker. We apologize for this back and forth but we mistakenly changed the behavior to not match what `SqlClient' supports. We now support using either syntax for adding parameters however we also respond exactly like `SqlClient' in that if you ask for the index of a parameter using a syntax different from when you added the parameter, the result will be -1. * Assembly now properly appears in the Visual Studio 2005 Add/Remove Reference dialog. * Fixed problem that prevented use of `SchemaOnly' or `SingleRow' command behaviors with stored procedures or prepared statements. * Added `MySqlParameterCollection.AddWithValue' and marked the `Add(name, value)' method as obsolete. * Return parameters created with DeriveParameters now have the name `RETURN_VALUE'. * Fixed problem with parameter name hashing where the hashes were not getting updated when parameters were removed from the collection. * Fixed problem with calling stored functions when a return parameter was not given. * Added `Use Procedure Bodies' connection string option to enable calling procedures without using procedure metadata. *Bugs fixed:* * `MySqlConnection.GetSchema' fails with `NullReferenceException' for Foreign Keys. (Bug #26660) * MySQL Connector/NET would fail to install under Windows Vista. (Bug #26430) * Opening a connection would be slow due to host name lookup. (Bug #26152) * Incorrect values/formats would be applied when the `OldSyntax' connection string option was used. (Bug #25950) * Registry would be incorrectly populated with installation locations. (Bug #25928) * Times with negative values would be returned incorrectly. (Bug #25912) * Returned data types of a `DataTypes' collection do not contain the right correct CLR data type. (Bug #25907) * `GetSchema' and `DataTypes' would throw an exception due to an incorrect table name. (Bug #25906) * `MySqlConnection' throws an exception when connecting to MySQL v4.1.7. (Bug #25726) * *Note `SELECT': select. did not work correctly when using a `WHERE' clause containing a UTF-8 string. (Bug #25651) * When closing and then re-opening a connection to a database, the character set specification is lost. (Bug #25614) * Filling a table schema through a stored procedure triggers a runtime error. (Bug #25609) * *Note `BINARY': binary-varbinary. and *Note `VARBINARY': binary-varbinary. columns would be returned as a string, not binary, data type. (Bug #25605) * A critical `ConnectionPool' error would result in repeated `System.NullReferenceException'. (Bug #25603) * The `UpdateRowSource.FirstReturnedRecord' method does not work. (Bug #25569) * When connecting to a MySQL Server earlier than version 4.1, the connection would hang when reading data. (Bug #25458) * Using `ExecuteScalar()' with more than one query, where one query fails, will hang the connection. (Bug #25443) * When a `MySqlConversionException' is raised on a remote object, the client application would receive a `SerializationException' instead. (Bug #24957) * When connecting to a server, the return code from the connection could be zero, even though the host name was incorrect. (Bug #24802) * High CPU utilization would be experienced when there is no idle connection waiting when using pooled connections through `MySqlPool.GetConnection'. (Bug #24373) * MySQL Connector/NET would not compile properly when used with Mono 1.2. (Bug #24263) * Applications would crash when calling with `CommandType' set to `StoredProcedure'.  File: manual.info, Node: connector-net-news-5-0-4, Next: connector-net-news-5-0-3, Prev: connector-net-news-5-0-5, Up: changes-5.0.x D.4.9.7 Changes in MySQL Connector/NET 5.0.4 (Not released) ........................................................... This is a new Beta development release, fixing recently discovered bugs. This section has no changelog entries.  File: manual.info, Node: connector-net-news-5-0-3, Next: connector-net-news-5-0-2, Prev: connector-net-news-5-0-4, Up: changes-5.0.x D.4.9.8 Changes in MySQL Connector/NET 5.0.3 (05 January 2007) .............................................................. *Functionality added or changed:* * Usage Advisor has been implemented. The Usage Advisor checks your queries and will report if you are using the connection inefficiently. * PerfMon hooks have been added to monitor the stored procedure cache hits and misses. * The `MySqlCommand' object now supports asynchronous query methods. This is implemented useg the `BeginExecuteNonQuery' and `EndExecuteNonQuery' methods. * Metadata from storaed procedures and stored function execution are cached. * The `CommandBuilder.DeriveParameters' function has been updated to the procedure cache. * The `ViewColumns' `GetSchema' collection has been updated. * Improved speed and performance by re-architecting certain sections of the code. * Support for the embedded server and client library have been removed from this release. Support will be added back to a later release. * The ShapZipLib library has been replaced with the deflate support provided within .NET 2.0. * SSL support has been updated. *Bugs fixed:* * Additional text added to error message (Bug #25178) * An exception would be raised, or the process would hang, if `SELECT' privileges on a database were not granted and a stored procedure was used. (Bug #25033) * When adding parameter objects to a command object, if the parameter direction is set to `ReturnValue' before the parameter is added to the command object then when the command is executed it throws an error. (Bug #25013) * Using `Driver.IsTooOld()' would return the wrong value. (Bug #24661) * When using a `DbNull.Value' as the value for a parameter value, and then later setting a specific value type, the command would fail with an exception because the wrong type was implied from the `DbNull.Value'. (Bug #24565) * Stored procedure executions are not thread safe. (Bug #23905) * Deleting a connection to a disconnected server when using the Visual Studio Plugin would cause an assertion failure. (Bug #23687) * Nested transactions (which are unsupported)do not raise an error or warning. (Bug #22400)  File: manual.info, Node: connector-net-news-5-0-2, Next: connector-net-news-5-0-1, Prev: connector-net-news-5-0-3, Up: changes-5.0.x D.4.9.9 Changes in MySQL Connector/NET 5.0.2 (06 November 2006) ............................................................... *Functionality added or changed:* * An `Ignore Prepare' option has been added to the connection string options. If enabled, prepared statements will be disabled application-wide. The default for this option is true. * Implemented a stored procedure cache. By default, the connector caches the metadata for the last 25 procedures that are seen. You can change the numbver of procedures that are cacheds by using the `procedure cache' connection string. * *Important change:* Due to a number of issues with the use of server-side prepared statements, MySQL Connector/NET 5.0.2 has disabled their use by default. The disabling of server-side prepared statements does not affect the operation of the connector in any way. To enable server-side prepared statements you must add the following configuration property to your connector string properties: ignore prepare=false The default value of this property is true. *Bugs fixed:* * One system where IPv6 was enabled, MySQL Connector/NET would incorrectly resolve host names. (Bug #23758) * Column names with accented characters were not parsed properly causing malformed column names in result sets. (Bug #23657) * An exception would be thrown when calling `GetSchemaTable' and `fields' was null. (Bug #23538) * A `System.FormatException' exception would be raised when invoking a stored procedure with an *Note `ENUM': enum. input parameter. (Bug #23268) * During installation, an antivirus error message would be raised (indicating a malicious script problem). (Bug #23245) * Creating a connection through the Server Explorer when using the Visual Studio Plugin would fail. The installer for the Visual Studio Plugin has been updated to ensure that MySQL Connector/NET 5.0.2 must be installed. (Bug #23071) * Using Windows Vista (RC2) as a nonprivileged user would raise a `Registry key 'Global' access denied'. (Bug #22882) * Within Mono, using the `PreparedStatement' interface could result in an error due to a `BitArray' copying error. (Bug #18186) * MySQL Connector/NET did not work as a data source for the `SqlDataSource' object used by ASP.NET 2.0. (Bug #16126)  File: manual.info, Node: connector-net-news-5-0-1, Next: connector-net-news-5-0-0, Prev: connector-net-news-5-0-2, Up: changes-5.0.x D.4.9.10 Changes in MySQL Connector/NET 5.0.1 (01 October 2006) ............................................................... *Bugs fixed:* * MySQL Connector/NET on a Turkish operating system, may fail to execute certain SQL statements correctly. (Bug #22452) * Starting a transaction on a connection created by `MySql.Data.MySqlClient.MySqlClientFactory', using `BeginTransaction' without specifying an isolation level, causes the SQL statement to fail with a syntax error. (Bug #22042) * The `MySqlexception' class is now derived from the `DbException' class. (Bug #21874) * The `#' would not be accepted within column/table names, even though it was valid. (Bug #21521) * You can now install the MySQL Connector/NET MSI package from the command line using the `/passive', `/quiet', `/q' options. (Bug #19994) * Submitting an empty string to a command object through `prepare' raises an `System.IndexOutOfRangeException', rather than a MySQL Connector/NET exception. (Bug #18391) * Using `ExecuteScalar' with a datetime field, where the value of the field is "0000-00-00 00:00:00", a `MySqlConversionException' exception would be raised. (Bug #11991) * An `MySql.Data.Types.MySqlConversionException' would be raised when trying to update a row that contained a date field, where the date field contained a zero value (0000-00-00 00:00:00). (Bug #9619) * Executing multiple queries as part of a transaction returns `There is already an openDataReader associated with this Connection which must be closed first'. (Bug #7248) * Incorrect field/data lengths could be returned for *Note `VARCHAR': char. UTF8 columns. Bug (#14592)  File: manual.info, Node: connector-net-news-5-0-0, Prev: connector-net-news-5-0-1, Up: changes-5.0.x D.4.9.11 Changes in MySQL Connector/NET 5.0.0 (08 August 2006) .............................................................. *Functionality added or changed:* * Replaced use of ICSharpCode with .NET 2.0 internal deflate support. * Refactored test suite to test all protocols in a single pass. * Added usage advisor warnings for requesting column values by the wrong type. * Reimplemented PacketReader/PacketWriter support into MySqlStream class. * Reworked connection string classes to be simpler and faster. * Added procedure metadata caching. * Added internal implemention of SHA1 so we don't have to distribute the OpenNetCF on mobile devices. * Implemented MySqlClientFactory class. * Added perfmon hooks for stored procedure cache hits and misses. * Implemented classes and interfaces for ADO.Net 2.0 support. * Added Async query methods. * Implemented Usage Advisor. * Completely refactored how column values are handled to avoid boxing in some cases. * Implemented MySqlConnectionBuilder class. *Bugs fixed:* * CommandText: Question mark in comment line is being parsed as a parameter. (Bug #6214)  File: manual.info, Node: changes-1.0.x, Next: connector-net-0-9-0, Prev: changes-5.0.x, Up: connector-net-news D.4.10 Changes in MySQL Connector/NET Version 1.0.x --------------------------------------------------- * Menu: * connector-net-news-1-0-11:: Changes in MySQL Connector/NET 1.0.11 (Not yet released) * connector-net-news-1-0-10:: Changes in MySQL Connector/NET 1.0.10 (24 August 2007) * connector-net-news-1-0-9:: Changes in MySQL Connector/NET 1.0.9 (02 February 2007) * connector-net-news-1-0-8:: Changes in MySQL Connector/NET 1.0.8 (20 October 2006) * connector-net-news-1-0-7:: Changes in MySQL Connector/NET 1.0.7 (21 November 2005) * connector-net-news-1-0-6:: Changes in MySQL Connector/NET 1.0.6 (03 October 2005) * connector-net-news-1-0-5:: Changes in MySQL Connector/NET 1.0.5 (29 August 2005) * connector-net-news-1-0-4:: Changes in MySQL Connector/NET 1.0.4 (20 January 2005) * connector-net-news-1-0-3:: Changes in MySQL Connector/NET 1.0.3 (12 October 2004 gamma) * connector-net-news-1-0-2:: Changes in MySQL Connector/NET 1.0.2 (15 November 2004 gamma) * connector-net-news-1-0-1:: Changes in MySQL Connector/NET 1.0.1 (27 October 2004 beta) * connector-net-news-1-0-0:: Changes in MySQL Connector/NET 1.0.0 (01 September 2004)  File: manual.info, Node: connector-net-news-1-0-11, Next: connector-net-news-1-0-10, Prev: changes-1.0.x, Up: changes-1.0.x D.4.10.1 Changes in MySQL Connector/NET 1.0.11 (Not yet released) ................................................................. *Bugs fixed:* * Attempting to utilize MySQL Connector .Net version 1.0.10 throws a fatal exception under Mono when pooling is enabled. (Bug #33682) * Setting the size of a string parameter after the value could cause an exception. (Bug #32094) * Creation of parameter objects with noninput direction using a constructor would fail. This was cause by some old legacy code preventing their use. (Bug #32093) * Memory usage could increase and decrease significantly when updating or inserting a large number of rows. (Bug #31090) * Commands executed from within the state change handeler would fail with a `NULL' exception. (Bug #30964) * Extracting data through XML functions within a query returns the data as `System.Byte[]'. This was due to MySQL Connector/NET incorrectly identifying *Note `BLOB': blob. fields as binary, rather than text. (Bug #30233) * Using compression in the MySQL connection with MySQL Connector/NET would be slower than using native (uncompressed) communication. (Bug #27865) * Changing the connection string of a connection to one that changes the parameter marker after the connection had been assigned to a command but before the connection is opened could cause parameters to not be found. (Bug #13991)  File: manual.info, Node: connector-net-news-1-0-10, Next: connector-net-news-1-0-9, Prev: connector-net-news-1-0-11, Up: changes-1.0.x D.4.10.2 Changes in MySQL Connector/NET 1.0.10 (24 August 2007) ............................................................... *Bugs fixed:* * An incorrect `ConstraintException' could be raised on an *Note `INSERT': insert. when adding rows to a table with a multiple-column unique key index. (Bug #30204) * The availability of a MySQL server would not be reset when using pooled connections (`pooling=true'). This would lead to the server being reported as unavailable, even if the server become available while the application was still running. (Bug #29409) * Publisher listed in "Add/Remove Programs" is not consistent with other MySQL products. (Bug #27253) * `MySqlParameterCollection' and parameters added with `Insert' method can not be retrieved later using `ParameterName'. (Bug #27135) * *Note `BINARY': binary-varbinary. and *Note `VARBINARY': binary-varbinary. columns would be returned as a string, not binary, data type. (Bug #25605) * A critical `ConnectionPool' error would result in repeated `System.NullReferenceException'. (Bug #25603) * When a `MySqlConversionException' is raised on a remote object, the client application would receive a `SerializationException' instead. (Bug #24957) * High CPU utilization would be experienced when there is no idle connection waiting when using pooled connections through `MySqlPool.GetConnection'. (Bug #24373)  File: manual.info, Node: connector-net-news-1-0-9, Next: connector-net-news-1-0-8, Prev: connector-net-news-1-0-10, Up: changes-1.0.x D.4.10.3 Changes in MySQL Connector/NET 1.0.9 (02 February 2007) ................................................................ *Functionality added or changed:* * The ICSharpCode ZipLib is no longer used by the Connector, and is no longer distributed with it. * *Important change:* Binaries for .NET 1.0 are no longer supplied with this release. If you need support for .NET 1.0, you must build from source. * Improved `CommandBuilder.DeriveParameters' to first try and use the procedure cache before querying for the stored procedure metadata. Return parameters created with `DeriveParameters' now have the name `RETURN_VALUE'. * An `Ignore Prepare' option has been added to the connection string options. If enabled, prepared statements will be disabled application-wide. The default for this option is true. * Implemented a stored procedure cache. By default, the connector caches the metadata for the last 25 procedures that are seen. You can change the numbver of procedures that are cacheds by using the `procedure cache' connection string. * *Important change:* Due to a number of issues with the use of server-side prepared statements, MySQL Connector/NET 5.0.2 has disabled their use by default. The disabling of server-side prepared statements does not affect the operation of the connector in any way. To enable server-side prepared statements you must add the following configuration property to your connector string properties: ignore prepare=false The default value of this property is true. *Bugs fixed:* * Times with negative values would be returned incorrectly. (Bug #25912) * `MySqlConnection' throws a `NullReferenceException' and `ArgumentNullException' when connecting to MySQL v4.1.7. (Bug #25726) * *Note `SELECT': select. did not work correctly when using a `WHERE' clause containing a UTF-8 string. (Bug #25651) * When closing and then re-opening a connection to a database, the character set specification is lost. (Bug #25614) * Trying to fill a table schema through a stored procedure triggers a runtime error. (Bug #25609) * Using `ExecuteScalar()' with more than one query, where one query fails, will hang the connection. (Bug #25443) * Additional text added to error message. (Bug #25178) * When adding parameter objects to a command object, if the parameter direction is set to `ReturnValue' before the parameter is added to the command object then when the command is executed it throws an error. (Bug #25013) * When connecting to a server, the return code from the connection could be zero, even though the host name was incorrect. (Bug #24802) * Using `Driver.IsTooOld()' would return the wrong value. (Bug #24661) * When using a `DbNull.Value' as the value for a parameter value, and then later setting a specific value type, the command would fail with an exception because the wrong type was implied from the `DbNull.Value'. (Bug #24565) * Stored procedure executions are not thread safe. (Bug #23905) * The `CommandBuilder' would mistakenly add insert parameters for a table column with auto incrementation enabled. (Bug #23862) * One system where IPv6 was enabled, MySQL Connector/NET would incorrectly resolve host names. (Bug #23758) * Nested transactions do not raise an error or warning. (Bug #22400) * An `System.OverflowException' would be raised when accessing a varchar field over 255 bytes. Bug (#23749) * Within Mono, using the `PreparedStatement' interface could result in an error due to a `BitArray' copying error. (Bug 18186)  File: manual.info, Node: connector-net-news-1-0-8, Next: connector-net-news-1-0-7, Prev: connector-net-news-1-0-9, Up: changes-1.0.x D.4.10.4 Changes in MySQL Connector/NET 1.0.8 (20 October 2006) ............................................................... *Functionality added or changed:* * Stored procedures are now cached. * The method for retrieving stored procedure metadata has been changed so that users without `SELECT' privileges on the `mysql.proc' table can use a stored procedure. *Bugs fixed:* * MySQL Connector/NET on a Turkish operating system, may fail to execute certain SQL statements correctly. (Bug #22452) * The `#' would not be accepted within column/table names, even though it was valid. (Bug #21521) * Calling Close on a connection after calling a stored procedure would trigger a `NullReferenceException'. (Bug #20581) * You can now install the MySQL Connector/NET MSI package from the command line using the `/passive', `/quiet', `/q' options. (Bug #19994) * The DiscoverParameters function would fail when a stored procedure used a *Note `NUMERIC': numeric-types. parameter type. (Bug #19515) * When running a query that included a date comparison, a DateReader error would be raised. (Bug #19481) * `IDataRecord.GetString' would raise `NullPointerException' for null values in returned rows. Method now throws `SqlNullValueException'. (Bug #19294) * Parameter substitution in queries where the order of parameters and table fields did not match would substitute incorrect values. (Bug #19261) * Submitting an empty string to a command object through `prepare' raises an `System.IndexOutOfRangeException', rather than a MySQL Connector/NET exception. (Bug #18391) * An exception would be raised when using an output parameter to a `System.String' value. (Bug #17814) * CHAR type added to MySqlDbType. (Bug #17749) * A *Note `SELECT': select. query on a table with a date with a value of `'0000-00-00'' would hang the application. (Bug #17736) * The CommandBuilder ignored Unsigned flag at Parameter creation. (Bug #17375) * When working with multiple threads, character set initialization would generate errors. (Bug #17106) * When using an unsigned 64-bit integer in a stored procedure, the unsigned bit would be lost stored. (Bug #16934) * `DataReader' would show the value of the previous row (or last row with nonnull data) if the current row contained a `datetime' field with a null value. (Bug #16884) * Unsigned data types were not properly supported. (Bug #16788) * The connection string parser did not permit single or double quotation marks in the password. (Bug #16659) * The `MySqlDateTime' class did not contain constructors. (Bug #15112) * Called `MySqlCommandBuilder.DeriveParameters' for a stored procedure that has no paramers would cause an application crash. (Bug #15077) * Using `ExecuteScalar' with a datetime field, where the value of the field is "0000-00-00 00:00:00", a `MySqlConversionException' exception would be raised. (Bug #11991) * An `MySql.Data.Types.MySqlConversionException' would be raised when trying to update a row that contained a date field, where the date field contained a zero value (0000-00-00 00:00:00). (Bug #9619) * When using `MySqlDataAdapter', connections to a MySQL server may remain open and active, even though the use of the connection has been completed and the data received. (Bug #8131) * Executing multiple queries as part of a transaction returns `There is already an openDataReader associated with this Connection which must be closed first'. (Bug #7248) * Incorrect field/data lengths could be returned for *Note `VARCHAR': char. UTF8 columns. Bug (#14592)  File: manual.info, Node: connector-net-news-1-0-7, Next: connector-net-news-1-0-6, Prev: connector-net-news-1-0-8, Up: changes-1.0.x D.4.10.5 Changes in MySQL Connector/NET 1.0.7 (21 November 2005) ................................................................ *Bugs fixed:* * Unsigned `tinyint' (NET byte) would lead to and incorrectly determined parameter type from the parameter value. (Bug #18570) * A `#42000Query was empty' exception occurred when executing a query built with `MySqlCommandBuilder', if the query string ended with a semicolon. (Bug #14631) * The parameter collection object's `Add()' method added parameters to the list without first checking to see whether they already existed. Now it updates the value of the existing parameter object if it exists. (Bug #13927) * Added support for the `cp932' character set. (Bug #13806) * Calling a stored procedure where a parameter contained special characters (such as `'@'') would produce an exception. Note that `ANSI_QUOTES' had to be enabled to make this possible. (Bug #13753) * The `Ping()' method did not update the `State' property of the `Connection' object. (Bug #13658) * Implemented the `MySqlCommandBuilder.DeriveParameters' method that is used to discover the parameters for a stored procedure. (Bug #13632) * A statement that contained multiple references to the same parameter could not be prepared. (Bug #13541)  File: manual.info, Node: connector-net-news-1-0-6, Next: connector-net-news-1-0-5, Prev: connector-net-news-1-0-7, Up: changes-1.0.x D.4.10.6 Changes in MySQL Connector/NET 1.0.6 (03 October 2005) ............................................................... *Bugs fixed:* * MySQL Connector/NET 1.0.5 could not connect on Mono. (Bug #13345) * Serializing a parameter failed if the first value passed in was `NULL'. (Bug #13276) * Field names that contained the following characters caused errors: `()%<>/' (Bug #13036) * The `nant' build sequence had problems. (Bug #12978) * The MySQL Connector/NET 1.0.5 installer would not install alongside MySQL Connector/NET 1.0.4. (Bug #12835)  File: manual.info, Node: connector-net-news-1-0-5, Next: connector-net-news-1-0-4, Prev: connector-net-news-1-0-6, Up: changes-1.0.x D.4.10.7 Changes in MySQL Connector/NET 1.0.5 (29 August 2005) .............................................................. *Bugs fixed:* * MySQL Connector/NET could not connect to MySQL 4.1.14. (Bug #12771) * With multiple hosts in the connection string, MySQL Connector/NET would not connect to the last host in the list. (Bug #12628) * The `ConnectionString' property could not be set when a `MySqlConnection' object was added with the designer. (Bug #12551, Bug #8724) * The `cp1250' character set was not supported. (Bug #11621) * A call to a stored procedure caused an exception if the stored procedure had no parameters. (Bug #11542) * Certain malformed queries would trigger a `Connection must be valid and open' error message. (Bug #11490) * Trying to use a stored procedure when `Connection.Database' was not populated generated an exception. (Bug #11450) * MySQL Connector/NET interpreted the new decimal data type as a byte array. (Bug #11294) * Added support to call a stored function from MySQL Connector/NET. (Bug #10644) * Connection could fail when .NET thread pool had no available worker threads. (Bug #10637) * Calling `MySqlConnection.clone' when a connection string had not yet been set on the original connection would generate an error. (Bug #10281) * Decimal parameters caused syntax errors. (Bug #10152, Bug #11550, Bug #10486) * Parameters were not recognized when they were separated by linefeeds. (Bug #9722) * The `MySqlCommandBuilder' class could not handle queries that referenced tables in a database other than the default database. (Bug #8382) * Trying to read a *Note `TIMESTAMP': datetime. column generated an exception. (Bug #7951) * MySQL Connector/NET could not work properly with certain regional settings. (WL#8228)  File: manual.info, Node: connector-net-news-1-0-4, Next: connector-net-news-1-0-3, Prev: connector-net-news-1-0-5, Up: changes-1.0.x D.4.10.8 Changes in MySQL Connector/NET 1.0.4 (20 January 2005) ............................................................... *Bugs fixed:* * `MySqlReader.GetInt32' throws exception if column is unsigned. (Bug #7755) * Quote character \222 not quoted in `EscapeString'. (Bug #7724) * GetBytes is working no more. (Bug #7704) * `MySqlDataReader.GetString(index)' returns non-Null value when field is `Null'. (Bug #7612) * Clone method bug in `MySqlCommand'. (Bug #7478) * Problem with Multiple resultsets. (Bug #7436) * `MySqlAdapter.Fill' method throws error message `Non-negative number required'. (Bug #7345) * `MySqlCommand.Connection' returns an IDbConnection. (Bug #7258) * Calling prepare causing exception. (Bug #7243) * Fixed problem with shared memory connections. * Added or filled out several more topics in the API reference documentation. * Fixed another small problem with prepared statements. * Fixed problem that causes named pipes to not work with some blob functionality.  File: manual.info, Node: connector-net-news-1-0-3, Next: connector-net-news-1-0-2, Prev: connector-net-news-1-0-4, Up: changes-1.0.x D.4.10.9 Changes in MySQL Connector/NET 1.0.3 (12 October 2004 gamma) ..................................................................... *Bugs fixed:* * Invalid query string when using inout parameters (Bug #7133) * Inserting `DateTime' causes `System.InvalidCastException' to be thrown. (Bug #7132) * `MySqlDateTime' in Datatables sorting by Text, not Date. (Bug #7032) * Exception stack trace lost when re-throwing exceptions. (Bug #6983) * Errors in parsing stored procedure parameters. (Bug #6902) * InvalidCast when using `DATE_ADD'-function. (Bug #6879) * Int64 Support in `MySqlCommand' Parameters. (Bug #6863) * Test suite fails with MySQL 4.0 because of case sensitivity of table names. (Bug #6831) * `MySqlDataReader.GetChar(int i)' throws `IndexOutOfRange' exception. (Bug #6770) * Integer "out" parameter from stored procedure returned as string. (Bug #6668) * An Open Connection has been Closed by the Host System. (Bug #6634) * Fixed Invalid character set index: 200. (Bug #6547) * Connections now do not have to give a database on the connection string. * Installer now includes options to install into GAC and create `Start Menu' items. * Fixed major problem with detecting null values when using prepared statements. * Fixed problem where multiple resultsets having different numbers of columns would cause a problem. * Added `ServerThread' property to `MySqlConnection' to expose server thread id. * Added Ping method to `MySqlConnection'. * Changed the name of the test suite to `MySql.Data.Tests.dll'. * Now *Note `SHOW COLLATION': show-collation. is used upon connection to retrieve the full list of charset ids. * Made MySQL the default named pipe name.  File: manual.info, Node: connector-net-news-1-0-2, Next: connector-net-news-1-0-1, Prev: connector-net-news-1-0-3, Up: changes-1.0.x D.4.10.10 Changes in MySQL Connector/NET 1.0.2 (15 November 2004 gamma) ....................................................................... *Bugs fixed:* * Fixed Objects not being disposed (Bug #6649) * Fixed Charset-map for UCS-2 (Bug #6541) * Fixed Zero date "0000-00-00" is returned wrong when filling Dataset (Bug #6429) * Fixed double type handling in MySqlParameter(string parameterName, object value). (Bug #6428) * Fixed Installation directory ignored using custom installation (Bug #6329) * Fixed #HY000 Illegal mix of collations (latin1_swedish_ci,IMPLICIT) and (utf8_general_ (Bug #6322) * Added the TableEditor CS and VB sample * Added charset connection string option * Fixed problem with MySqlBinary where string values could not be used to update extended text columns * Provider is now using character set specified by server as default * Updated the installer to include the new samples * Fixed problem where setting command text leaves the command in a prepared state * Fixed Long inserts take very long time (Bu #5453) * Fixed problem where calling stored procedures might cause an "Illegal mix of collations" problem.  File: manual.info, Node: connector-net-news-1-0-1, Next: connector-net-news-1-0-0, Prev: connector-net-news-1-0-2, Up: changes-1.0.x D.4.10.11 Changes in MySQL Connector/NET 1.0.1 (27 October 2004 beta) ..................................................................... *Bugs fixed:* * Fixed IndexOutOfBounds when reading BLOB with DataReader with GetString(index) (Bug #6230) * Fixed GetBoolean returns wrong values (Bug #6227) * Fixed Method TokenizeSql() uses only a limited set of valid characters for parameters (Bug #6217) * Fixed NET Connector source missing resx files (Bug #6216) * Fixed System.OverflowException when using `YEAR' data type. (Bug #6036) * Fixed MySqlDateTime sets IsZero property on all subseq.records after first zero found (Bug #6006) * Fixed serializing of floating point parameters (double, numeric, single, decimal) (Bug #5900) * Fixed missing Reference in DbType setter (Bug #5897) * Fixed Parsing the ';' char (Bug #5876) * Fixed DBNull Values causing problems with retrieving/updating queries. (Bug #5798) * IsNullable error (Bug #5796) * Fixed problem where MySqlParameterCollection.Add() would throw unclear exception when given a null value (Bug #5621) * Fixed constructor initialize problems in MySqlCommand() (Bug #5613) * Fixed Yet Another "object reference not set to an instance of an object" (Bug #5496) * Fixed Can't display Chinese correctly (Bug #5288) * Fixed MySqlDataReader and 'show tables from ...' behavior (Bug #5256) * Fixed problem in PacketReader where it could try to allocate the wrong buffer size in EnsureCapacity * Fixed problem where using old syntax while using the interfaces caused problems * Fixed BUG #5458 Calling GetChars on a longtext column throws an exception * Added test case for resetting the command text on a prepared command * Fixed BUG #5388 DataReader reports all rows as NULL if one row is NULL * Fixed problem where connection lifetime on the connect string was not being respected * Fixed BUG #5602 Possible bug in MySqlParameter(string, object) constructor * Field buffers being reused to decrease memory allocations and increase speed * Fixed BUG #5392 MySqlCommand sees "?" as parameters in string literals * Added Aggregate function test (wasn't really a bug) * Using PacketWriter instead of Packet for writing to streams * Implemented SequentialAccess * Fixed problem with ConnectionInternal where a key might be added more than once * Fixed Russian character support as well * Fixed BUG #5474 cannot run a stored procedure populating mysqlcommand.parameters * Fixed problem where connector was not issuing a CMD_QUIT before closing the socket * Fixed problem where Min Pool Size was not being respected * Refactored compression code into CompressedStream to clean up NativeDriver * CP1252 is now used for Latin1 only when the server is 4.1.2 and later * Fixed BUG #5469 Setting DbType throws NullReferenceException * Virtualized driver subsystem so future releases could easily support client or embedded server support  File: manual.info, Node: connector-net-news-1-0-0, Prev: connector-net-news-1-0-1, Up: changes-1.0.x D.4.10.12 Changes in MySQL Connector/NET 1.0.0 (01 September 2004) .................................................................. *Bugs fixed:* * Thai encoding not correctly supported. (Bug #3889) * Bumped version number to 1.0.0 for beta 1 release. * Removed all of the XML comment warnings. * Added `COPYING.rtf' file for use in installer. * Updated many of the test cases. * Fixed problem with using compression. * Removed some last references to ByteFX.  File: manual.info, Node: connector-net-0-9-0, Next: connector-net-news-0-76, Prev: changes-1.0.x, Up: connector-net-news D.4.11 Changes in MySQL Connector/NET Version 0.9.0 (30 August 2004) -------------------------------------------------------------------- * Added test fixture for prepared statements. * All type classes now implement a `SerializeBinary' method for sending their data to a `PacketWriter'. * Added `PacketWriter' class that will enable future low-memory large object handling. * Fixed many small bugs in running prepared statements and stored procedures. * Changed command so that an exception will not be thrown in executing a stored procedure with parameters in old syntax mode. * `SingleRow' behavior now working right even with limit. * `GetBytes' now only works on binary columns. * Logger now truncates long SQL commands so blob columns do not blow out our log. * Host and database now have a default value of "" unless otherwise set. * Connection Timeout seems to be ignored. (Bug#5214) * Added test case for bug# 5051: GetSchema not working correctly. * Fixed problem where `GetSchema' would return false for `IsUnique' when the column is key. * `MySqlDataReader GetXXX' methods now using the field level `MySqlValue' object and not performing conversions. * `DataReader' returning `NULL' for time column. (Bug#5097) * Added test case for *Note `LOAD DATA LOCAL INFILE': load-data. * Added replacetext custom nant task. * Added `CommandBuilderTest' fixture. * Added Last One Wins feature to `CommandBuilder'. * Fixed persist security info case problem. * Fixed `GetBool' so that 1, true, "true", and "yes" all count as true. * Make parameter mark configurable. * Added the "old syntax" connection string parameter to enable use of @ parameter marker. * `MySqlCommandBuilder'. (Bug#4658) * `ByteFX.MySqlClient' caches passwords if `Persist Security Info' is false. (Bug#4864) * Updated license banner in all source files to include FLOSS exception. * Added new .Types namespace and implementations for most current MySql types. * Added `MySqlField41' as a subclass of `MySqlField'. * Changed many classes to now use the new .Types types. * Changed type `enum int' to `Int32', `short' to `Int16', and `bigint' to `Int64'. * Added dummy types `UInt16', `UInt32', and `UInt64' to allow an unsigned parameter to be made. * Connections are now reset when they are pulled from the connection pool. * Refactored auth code in driver so it can be used for both auth and reset. * Added `UserReset' test in `PoolingTests.cs'. * Connections are now reset using `COM_CHANGE_USER' when pulled from the pool. * Implemented `SingleResultSet' behavior. * Implemented support of unicode. * Added char set mappings for utf-8 and ucs-2. * Time fields overflow using bytefx .net mysql driver (Bug#4520) * Modified time test in data type test fixture to check for time spans where hours > 24. * Wrong string with backslash escaping in `ByteFx.Data.MySqlClient.MySqlParameter'. (Bug#4505) * Added code to Parameter test case TestQuoting to test for backslashes. * `MySqlCommandBuilder' fails with multi-word column names. (Bug#4486) * Fixed bug in `TokenizeSql' where underscore would terminate character capture in parameter name. * Added test case for spaces in column names. * `MySqlDataReader.GetBytes' do not work correctly. (Bug#4324) * Added `GetBytes()' test case to `DataReader' test fixture. * Now reading all server variables in `InternalConnection.Configure' into `Hashtable'. * Now using `string[]' for index map in `CharSetMap'. * Added CRInSQL test case for carriage returns in SQL. * Setting maxPacketSize to default value in `Driver.ctor'. * Setting `MySqlDbType' on a parameter doesn't set generic type. (Bug#4442) * Removed obsolete data types `Long' and `LongLong'. * Overflow exception thrown when using "use pipe" on connection string. (Bug#4071) * Changed "use pipe" keyword to "pipe name" or just "pipe". * Enable reading multiple resultsets from a single query. * Added flags attribute to `ServerStatusFlags' enum. * Changed name of `ServerStatus' enum to `ServerStatusFlags'. * Inserted data row doesn't update properly. * Error processing show create table. (Bug#4074) * Change `Packet.ReadLenInteger' to `ReadPackedLong' and added `packet.ReadPackedInteger' that always reads integers packed with 2,3,4. * Added `syntax.cs' test fixture to test various SQL syntax bugs. * Improper handling of time values. Now time value of 00:00:00 is not treated as null. (Bug#4149) * Moved all test suite files into `TestSuite' folder. * Fixed bug where null column would move the result packet pointer backward. * Added new nant build script. * Clear tablename so it will be regen'ed properly during the next `GenerateSchema'. (Bug#3917) * `GetValues' was always returning zero and was also always trying to copy all fields rather than respecting the size of the array passed in. (Bug#3915) * Implemented shared memory access protocol. * Implemented prepared statements for MySQL 4.1. * Implemented stored procedures for MySQL 5.0. * Renamed `MySqlInternalConnection' to `InternalConnection'. * SQL is now parsed as chars, fixes problems with other languages. * Added logging and allow batch connection string options. * `RowUpdating' event not set when setting the `DataAdapter' property. (Bug#3888) * Fixed bug in char set mapping. * Implemented 4.1 authentication. * Improved open/auth code in driver. * Improved how connection bits are set during connection. * Database name is now passed to server during initial handshake. * Changed namespace for client to `MySql.Data.MySqlClient'. * Changed assembly name of client to `MySql.Data.dll'. * Changed license text in all source files to GPL. * Added the `MySqlClient.build' Nant file. * Removed the mono batch files. * Moved some of the unused files into notused folder so nant build file can use wildcards. * Implemented shared memory access. * Major revamp in code structure. * Prepared statements now working for MySql 4.1.1 and later. * Finished implementing auth for 4.0, 4.1.0, and 4.1.1. * Changed namespace from `MySQL.Data.MySQLClient' back to `MySql.Data.MySqlClient'. * Fixed bug in `CharSetMapping' where it was trying to use text names as ints. * Changed namespace to `MySQL.Data.MySQLClient'. * Integrated auth changes from UC2004. * Fixed bug where calling any of the GetXXX methods on a datareader before or after reading data would not throw the appropriate exception (thanks Luca Morelli). * Added `TimeSpan' code in parameter.cs to properly serialize a timespan object to mysql time format (thanks Gianluca Colombo). * Added `TimeStamp' to parameter serialization code. Prevented `DataAdapter' updates from working right (thanks Michael King). * Fixed a misspelling in `MySqlHelper.cs' (thanks Patrick Kristiansen).  File: manual.info, Node: connector-net-news-0-76, Next: connector-net-news-0-75, Prev: connector-net-0-9-0, Up: connector-net-news D.4.12 Changes in MySQL Connector/NET Version 0.76 -------------------------------------------------- * Driver now using charset number given in handshake to create encoding. * Changed command editor to point to `MySqlClient.Design'. * Fixed bug in `Version.isAtLeast'. * Changed `DBConnectionString' to support changes done to `MySqlConnectionString'. * Removed `SqlCommandEditor' and `DataAdapterPreviewDialog'. * Using new long return values in many places. * Integrated new `CompressedStream' class. * Changed `ConnectionString' and added attributes to permit it to be used in `MySqlClient.Design'. * Changed `packet.cs' to support newer lengths in `ReadLenInteger'. * Changed other classes to use new properties and fields of `MySqlConnectionString'. * `ConnectionInternal' is now using PING to see whether the server is available. * Moved toolbox bitmaps into resource folder. * Changed `field.cs' to permit values to come directly from row buffer. * Changed to use the new driver.Send syntax. * Using a new packet queueing system. * Started work handling the "broken" compression packet handling. * Fixed bug in `StreamCreator' where failure to connect to a host would continue to loop infinitly (thanks Kevin Casella). * Improved connectstring handling. * Moved designers into Pro product. * Removed some old commented out code from `command.cs'. * Fixed a problem with compression. * Fixed connection object where an exception throw prior to the connection opening would not leave the connection in the connecting state (thanks Chris Cline). * Added GUID support. * Fixed sequence out of order bug (thanks Mark Reay).  File: manual.info, Node: connector-net-news-0-75, Next: connector-net-0-74, Prev: connector-net-news-0-76, Up: connector-net-news D.4.13 Changes in MySQL Connector/NET Version 0.75 -------------------------------------------------- * Enum values now supported as parameter values (thanks Philipp Sumi). * Year data type now supported. * Fixed compression. * Fixed bug where a parameter with a `TimeSpan' as the value would not serialize properly. * Fixed bug where default constructor would not set default connection string values. * Added some XML comments to some members. * Work to fix/improve compression handling. * Improved `ConnectionString' handling so that it better matches the standard set by `SqlClient'. * A `MySqlException' is now thrown if a user name is not included in the connection string. * Localhost is now used as the default if not specified on the connection string. * An exception is now thrown if an attempt is made to set the connection string while the connection is open. * Small changes to `ConnectionString' docs. * Removed `MultiHostStream' and `MySqlStream'. Replaced it with `Common/StreamCreator'. * Added support for Use Pipe connection string value. * Added Platform class for easier access to platform utility functions. * Fixed small pooling bug where new connection was not getting created after `IsAlive' fails. * Added `Platform.cs' and `StreamCreator.cs'. * Fixed `Field.cs' to properly handle 4.1 style timestamps. * Changed `Common.Version' to `Common.DBVersion' to avoid name conflict. * Fixed `field.cs' so that text columns return the right field type. * Added `MySqlError' class to provide some reference for error codes (thanks Geert Veenstra).  File: manual.info, Node: connector-net-0-74, Next: connector-net-news-0-71, Prev: connector-net-news-0-75, Up: connector-net-news D.4.14 Changes in MySQL Connector/NET Version 0.74 -------------------------------------------------- * Added Unix socket support (thanks Mohammad DAMT). * Only calling `Thread.Sleep' when no data is available. * Improved escaping of quote characters in parameter data. * Removed misleading comments from `parameter.cs'. * Fixed pooling bug. * Fixed `ConnectionString' editor dialog (thanks marco p (pomarc)). * `UserId' now supported in connection strings (thanks Jeff Neeley). * Attempting to create a parameter that is not input throws an exception (thanks Ryan Gregg). * Added much documentation. * Checked in new `MultiHostStream' capability. Big thanks to Dan Guisinger for this. he originally submitted the code and idea of supporting multiple machines on the connect string. * Added a lot of documentation. * Fixed speed issue with 0.73. * Changed to Thread.Sleep(0) in MySqlDataStream to help optimize the case where it doesn't need to wait (thanks Todd German). * Prepopulating the idlepools to `MinPoolSize'. * Fixed `MySqlPool' deadlock condition as well as stupid bug where CreateNewPooledConnection was not ever adding new connections to the pool. Also fixed `MySqlStream.ReadBytes' and `ReadByte' to not use `TicksPerSecond' which does not appear to always be right. (thanks Matthew J. Peddlesden) * Fix for precision and scale (thanks Matthew J. Peddlesden). * Added `Thread.Sleep(1)' to stream reading methods to be more cpu friendly (thanks Sean McGinnis). * Fixed problem where `ExecuteReader' would sometime return null (thanks Lloyd Dupont). * Fixed major bug with null field handling (thanks Naucki). * Enclosed queries for `max_allowed_packet' and `characterset' inside try catch (and set defaults). * Fixed problem where socket was not getting closed properly (thanks Steve!). * Fixed problem where `ExecuteNonQuery' was not always returning the right value. * Fixed `InternalConnection' to not use `@@session.max_allowed_packet' but use `@@max_allowed_packet'. (Thanks Miguel) * Added many new XML doc lines. * Fixed SQL parsing to not send empty queries (thanks Rory). * Fixed problem where the reader was not unpeeking the packet on close. * Fixed problem where user variables were not being handled (thanks Sami Vaaraniemi). * Fixed loop checking in the MySqlPool (thanks Steve M. Brown) * Fixed `ParameterCollection.Add' method to match `SqlClient' (thanks Joshua Mouch). * Fixed `ConnectionString' parsing to handle no and yes for boolean and not lowercase values (thanks Naucki). * Added `InternalConnection' class, changes to pooling. * Implemented Persist Security Info. * Added `security.cs' and `version.cs' to project * Fixed `DateTime' handling in `Parameter.cs' (thanks Burkhard Perkens-Golomb). * Fixed parameter serialization where some types would throw a cast exception. * Fixed `DataReader' to convert all returned values to prevent casting errors (thanks Keith Murray). * Added code to `Command.ExecuteReader' to return null if the initial SQL statement throws an exception (thanks Burkhard Perkens-Golomb). * Fixed `ExecuteScalar' bug introduced with restructure. * Restructure to permit `LOCAL DATA INFILE' and better sequencing of packets. * Fixed several bugs related to restructure. * Early work done to support more secure passwords in MySQL 4.1. Old passwords in 4.1 not supported yet. * Parameters appearing after system parameters are now handled correctly (Adam M. (adammil)). * Strings can now be assigned directly to blob fields (Adam M.). * Fixed float parameters (thanks Pent). * Improved Parameter constructor and `ParameterCollection.Add' methods to better match SqlClient (thanks Joshua Mouch). * Corrected `Connection.CreateCommand' to return a `MySqlCommand' type. * Fixed connection string designer dialog box problem (thanks Abraham Guyt). * Fixed problem with sending commands not always reading the response packet (thanks Joshua Mouch). * Fixed parameter serialization where some blobs types were not being handled (thanks Sean McGinnis). * Removed spurious `MessageBox.show' from `DataReader' code (thanks Joshua Mouch). * Fixed a nasty bug in the split SQL code (thanks everyone!).  File: manual.info, Node: connector-net-news-0-71, Next: connector-net-news-0-70, Prev: connector-net-0-74, Up: connector-net-news D.4.15 Changes in MySQL Connector/NET Version 0.71 -------------------------------------------------- * Fixed bug in `MySqlStream' where too much data could attempt to be read (thanks Peter Belbin) * Implemented `HasRows' (thanks Nash Pherson). * Fixed bug where tables with more than 252 columns cause an exception (thanks Joshua Kessler). * Fixed bug where SQL statements ending in ; would cause a problem (thanks Shane Krueger). * Fixed bug in driver where error messages were getting truncated by 1 character (thanks Shane Krueger). * Made `MySqlException' serializable (thanks Mathias Hasselmann).  File: manual.info, Node: connector-net-news-0-70, Next: connector-net-news-0-68, Prev: connector-net-news-0-71, Up: connector-net-news D.4.16 Changes in MySQL Connector/NET Version 0.70 -------------------------------------------------- * Updated some of the character code pages to be more accurate. * Fixed problem where readers could be opened on connections that had readers open. * Moved test to separate assembly `MySqlClientTests'. * Fixed stupid problem in driver with sequence out of order (Thanks Peter Belbin). * Added some pipe tests. * Increased default max pool size to 50. * Compiles with Mono 0-24. * Fixed connection and data reader dispose problems. * Added `String' data type handling to parameter serialization. * Fixed sequence problem in driver that occurred after thrown exception (thanks Burkhard Perkens-Golomb). * Added support for `CommandBehavior.SingleRow' to `DataReader'. * Fixed command SQL processing so quotation marks are better handled (thanks Theo Spears). * Fixed parsing of double, single, and decimal values to account for non-English separators. You still have to use the right syntax if you using hard coded SQL, but if you use parameters the code will convert floating point types to use '.' appropriately internal both into the server and out. * Added `MySqlStream' class to simplify timeouts and driver coding. * Fixed `DataReader' so that it is closed properly when the associated connection is closed. [thanks smishra] * Made client more SqlClient compliant so that DataReaders have to be closed before the connection can be used to run another command. * Improved `DBNull.Value' handling in the fields. * Added several unit tests. * Fixed `MySqlException' base class. * Improved driver coding * Fixed bug where NextResult was returning false on the last resultset. * Added more tests for MySQL. * Improved casting problems by equating unsigned 32bit values to Int64 and unsigned 16bit values to Int32, and so forth. * Added new constructor for `MySqlParameter' for (name, type, size, srccol) * Fixed bug in `MySqlDataReader' where it didn't check for null fieldlist before returning field count. * Started adding `MySqlClient' unit tests (added `MySqlClient/Tests' folder and some test cases). * Fixed some things in Connection String handling. * Moved `INIT_DB' to `MySqlPool'. I may move it again, this is in preparation of the conference. * Fixed bug inside `CommandBuilder' that prevented inserts from happening properly. * Reworked some of the internals so that all three execute methods of Command worked properly. * Fixed many small bugs found during benchmarking. * The first cut of `CoonectionPooling' is working. "min pool size" and "max pool size" are respected. * Work to enable multiple resultsets to be returned. * Character sets are handled much more intelligently now. The driver queries MySQL at startup for the default character set. That character set is then used for conversions if that code page can be loaded. If not, then the default code page for the current OS is used. * Added code to save the inferred type in the name,value constructor of `Parameter'. * Also, inferred type if value of null parameter is changed using `Value' property. * Converted all files to use proper Camel case. MySQL is now MySql in all files. PgSQL is now PgSql. * Added attribute to PgSql code to prevent designer from trying to show. * Added `MySQLDbType' property to Parameter object and added proper conversion code to convert from `DbType' to `MySQLDbType'). * Removed unused `ObjectToString' method from `MySQLParameter.cs'. * Fixed `Add(..)' method in `ParameterCollection' so that it doesn't use `Add(name, value)' instead. * Fixed `IndexOf' and `Contains' in `ParameterCollection' to be aware that parameter names are now stored without @. * Fixed `Command.ConvertSQLToBytes' so it only permits characters that can be in MySQL variable names. * Fixed `DataReader' and `Field' so that blob fields read their data from `Field.cs' and `GetBytes' works right. * Added simple query builder editor to `CommandText' property of `MySQLCommand'. * Fixed `CommandBuilder' and `Parameter' serialization to account for Parameters not storing @ in their names. * Removed `MySQLFieldType' enum from Field.cs. Now using `MySQLDbType' enum. * Added `Designer' attribute to several classes to prevent designer view when using VS.Net. * Fixed Initial catalog typo in `ConnectionString' designer. * Removed 3 parameter constructor for `MySQLParameter' that conflicted with (name, type, value). * Changed `MySQLParameter' so `paramName' is now stored without leading @ (this fixed null inserts when using designer). * Changed `TypeConverter' for `MySQLParameter' to use the constructor with all properties.  File: manual.info, Node: connector-net-news-0-68, Next: connector-net-news-0-65, Prev: connector-net-news-0-70, Up: connector-net-news D.4.17 Changes in MySQL Connector/NET Version 0.68 -------------------------------------------------- * Fixed sequence issue in driver. * Added `DbParametersEditor' to make parameter editing more like `SqlClient'. * Fixed `Command' class so that parameters can be edited using the designer * Update connection string designer to support `Use Compression' flag. * Fixed string encoding so that European characters will work correctly. * Creating base classes to aid in building new data providers. * Added support for UID key in connection string. * Field, parameter, command now using DBNull.Value instead of null. * `CommandBuilder' using `DBNull.Value'. * `CommandBuilder' now builds insert command correctly when an auto_insert field is not present. * Field now uses typeof keyword to return `System.Types' (performance).  File: manual.info, Node: connector-net-news-0-65, Next: connector-net-news-0-60, Prev: connector-net-news-0-68, Up: connector-net-news D.4.18 Changes in MySQL Connector/NET Version 0.65 -------------------------------------------------- * `MySQLCommandBuilder' now implemented. * Transaction support now implemented (not all table types support this). * `GetSchemaTable' fixed to not use xsd (for Mono). * Driver is now Mono-compatible. * TIME data type now supported. * More work to improve Timestamp data type handling. * Changed signatures of all classes to match corresponding `SqlClient' classes.  File: manual.info, Node: connector-net-news-0-60, Next: connector-net-news-0-50, Prev: connector-net-news-0-65, Up: connector-net-news D.4.19 Changes in MySQL Connector/NET Version 0.60 -------------------------------------------------- * Protocol compression using SharpZipLib (www.icsharpcode.net). * Named pipes on Windows now working properly. * Work done to improve `Timestamp' data type handling. * Implemented `IEnumerable' on `DataReader' so `DataGrid' would work.  File: manual.info, Node: connector-net-news-0-50, Prev: connector-net-news-0-60, Up: connector-net-news D.4.20 Changes in MySQL Connector/NET Version 0.50 -------------------------------------------------- * Speed increased dramatically by removing bugging network sync code. * Driver no longer buffers rows of data (more ADO.Net compliant). * Conversion bugs related to *Note `TIMESTAMP': datetime. and *Note `DATETIME': datetime. fields fixed.  File: manual.info, Node: vstudio-plugin-news, Next: cj-news, Prev: connector-net-news, Up: news D.5 MySQL Visual Studio Plugin Change History ============================================= * Menu: * vstudio-plugin-news-1-0-3:: Changes in MySQL Visual Studio Plugin 1.0.3 (Not yet released) * vstudio-plugin-news-1-0-2:: Changes in MySQL Visual Studio Plugin 1.0.2 (Not yet released) * vstudio-plugin-news-1-0-1:: Changes in MySQL Visual Studio Plugin 1.0.1 (04 October 2006) * vstudio-plugin-news-1-0-0:: Changes in MySQL Visual Studio Plugin 1.0.0 (04 October 2006) *Note*: As of Connector/NET 5.1.2 (14 June 2007), the Visual Studion Plugin is part of the main Connector/NET package. For the change history for the Visual Studio Plugin, see *Note connector-net-news::.  File: manual.info, Node: vstudio-plugin-news-1-0-3, Next: vstudio-plugin-news-1-0-2, Prev: vstudio-plugin-news, Up: vstudio-plugin-news D.5.1 Changes in MySQL Visual Studio Plugin 1.0.3 (Not yet released) -------------------------------------------------------------------- *Bugs fixed:* * Running queries based on a stored procedure would cause the data set designer to terminate. (Bugs #26364) * DataSet wizard would show all tables instead of only the tables available within the selected database. (Bugs #26348)  File: manual.info, Node: vstudio-plugin-news-1-0-2, Next: vstudio-plugin-news-1-0-1, Prev: vstudio-plugin-news-1-0-3, Up: vstudio-plugin-news D.5.2 Changes in MySQL Visual Studio Plugin 1.0.2 (Not yet released) -------------------------------------------------------------------- *Bugs fixed:* * The Add Connection dialog of the Server Explorer would freeze when accessing databases with capitalized characters in their name. (Bug #24875) * Creating a connection through the Server Explorer when using the Visual Studio Plugin would fail. The installer for the Visual Studio Plugin has been updated to ensure that Connector/NET 5.0.2 must be installed. (Bug #23071)  File: manual.info, Node: vstudio-plugin-news-1-0-1, Next: vstudio-plugin-news-1-0-0, Prev: vstudio-plugin-news-1-0-2, Up: vstudio-plugin-news D.5.3 Changes in MySQL Visual Studio Plugin 1.0.1 (04 October 2006) ------------------------------------------------------------------- This is a bug fix release to resolve an incompatibility issue with Connector/NET 5.0.1. It is critical that this release only be used with Connector/NET 5.0.1. After installing Connector/NET 5.0.1, you will need to make a small change in your machine.config file. This file should be located at `%win%\Microsoft.Net\Framework\v2.0.50727\CONFIG\machine.config' (`%win%' should be the location of your Windows folder). Near the bottom of the file you will see a line like this: It needs to be changed to be like this: This section has no changelog entries.  File: manual.info, Node: vstudio-plugin-news-1-0-0, Prev: vstudio-plugin-news-1-0-1, Up: vstudio-plugin-news D.5.4 Changes in MySQL Visual Studio Plugin 1.0.0 (04 October 2006) ------------------------------------------------------------------- *Bugs fixed:* * Ability to work with MySQL objects (tables, views, stored procedures, etc) from within Server Explorer. * DDEX (Data Designer Extensibility) compatibility.  File: manual.info, Node: cj-news, Next: news-connector-mxj, Prev: vstudio-plugin-news, Up: news D.6 MySQL Connector/J Change History ==================================== * Menu: * cj-news-5-1:: Changes in MySQL Connector/J 5.1.x * cj-news-5-0:: Changes in MySQL Connector/J 5.0.x * cg-news-3-1:: Changes in MySQL Connector/J 3.1.x * cg-news-3-0:: Changes in MySQL Connector/J 3.0.x * cj-news-2-0:: Changes in MySQL Connector/J 2.0.x * cj-news-1-2b:: Changes in MySQL Connector/J 1.2b (04 July 1999) * cg-news-1-0:: Changes in MySQL Connector/J 1.2.x and lower  File: manual.info, Node: cj-news-5-1, Next: cj-news-5-0, Prev: cj-news, Up: cj-news D.6.1 Changes in MySQL Connector/J 5.1.x ---------------------------------------- * Menu: * cj-news-5-1-15:: Changes in MySQL Connector/J 5.1.15 (09 February 2011) * cj-news-5-1-14:: Changes in MySQL Connector/J 5.1.14 (6th December 2010) * cj-news-5-1-13:: Changes in MySQL Connector/J 5.1.13 (24 June 2010) * cj-news-5-1-12:: Changes in MySQL Connector/J 5.1.12 (18 February 2010) * cj-news-5-1-11:: Changes in MySQL Connector/J 5.1.11 (21 January 2010) * cj-news-5-1-10:: Changes in MySQL Connector/J 5.1.10 (23 September 2009) * cj-news-5-1-9:: Changes in MySQL Connector/J 5.1.9 (21 September 2009) * cj-news-5-1-8:: Changes in MySQL Connector/J 5.1.8 (16 July 2009) * cj-news-5-1-7:: Changes in MySQL Connector/J 5.1.7 (21 October 2008) * cj-news-5-1-6:: Changes in MySQL Connector/J 5.1.6 (07 March 2008) * cj-news-5-1-5:: Changes in MySQL Connector/J 5.1.5 (09 October 2007) * cj-news-5-1-4:: Changes in MySQL Connector/J 5.1.4 (Not Released) * cj-news-5-1-3:: Changes in MySQL Connector/J 5.1.3 (10 September 2007) * cj-news-5-1-2:: Changes in MySQL Connector/J 5.1.2 (29 June 2007) * cj-news-5-1-1:: Changes in MySQL Connector/J 5.1.1 (22 June 2007) * cj-news-5-1-0:: Changes in MySQL Connector/J 5.1.0 (11 April 2007)  File: manual.info, Node: cj-news-5-1-15, Next: cj-news-5-1-14, Prev: cj-news-5-1, Up: cj-news-5-1 D.6.1.1 Changes in MySQL Connector/J 5.1.15 (09 February 2011) .............................................................. Fixes bugs found since release 5.1.14. *Bugs fixed:* * Optional logging class `com.mysql.jdbc.log.Log4JLogger' was not included in the source/binary package for 5.1.14. 5.1.15 will ship with an SLF4J logger (which can then be plugged into Log4J). Unfortunately, it is not possible to ship a direct Log4J integration because the GPL is not compatible with Log4J's license. (Bug #59511, Bug #11766408) * The hard-coded list of reserved words in Connector/J was not updated to reflect the list of reserved words in MySQL Server 5.5. (Bug #59224) * MySqlProcedure accepted null arguments as parameters, however the JDBC meta data did not indicate that. (Bug #38367, Bug #11749186) * Using Connector/J to connect from a z/OS machine to a MySQL Server failed when the database name to connect to was included in the connection URL. This was because the name was sent in z/OS default platform encoding, but the MySQL Server expected Latin1. It should be noted that when connecting from systems that do not use Latin1 as the default platform encoding, the following connection string options can be useful: `passwordCharacterEncoding=ASCII' and `characterEncoding=ASCII'. (Bug #18086, Bug #11745647)  File: manual.info, Node: cj-news-5-1-14, Next: cj-news-5-1-13, Prev: cj-news-5-1-15, Up: cj-news-5-1 D.6.1.2 Changes in MySQL Connector/J 5.1.14 (6th December 2010) ............................................................... Fixes bugs found since release 5.1.13. *Functionality added or changed:* * Connector/J's load-balancing functionality only allowed the following events to trigger failover: * Transaction commit/rollback * CommunicationExceptions * Matches to user-defined Exceptions using the loadBalanceSQLStateFailover, loadBalanceSQLExceptionSubclassFailover or loadBalanceExceptionChecker property. This meant that connections where auto-commit was enabled were not balanced, except for Exceptions, and this was problematic in the case of distribution of read-only work across slaves in a replication deployment. The ability to load-balance while auto-commit is enabled has now been added to Connector/J. This introduces two new properties: 1. loadBalanceAutoCommitStatementThreshold - defines the number of matching statements which will trigger the driver to (potentially) swap physical server connections. The default value (0) retains the previously-established behavior that connections with auto-commit enabled are never balanced. 2. loadBalanceAutoCommitStatementRegex - the regular expression against which statements must match. The default value (blank) matches all statements. Load-balancing will be done after the statement is executed, before control is returned to the application. If rebalancing fails, the driver will silently swallow the resulting Exception (as the statement itself completed successfully). (Bug #55723) *Bugs fixed:* * Connection failover left slave/secondary in read-only mode. Failover attempts between two read-write masters did not properly set `this.currentConn.setReadOnly(false)'. (Bug #58706) * Connector/J mapped both 3-byte and 4-byte UTF8 encodings to the same Java UTF8 encoding. To use 3-byte UTF8 with Connector/J set `characterEncoding=utf8' and set `useUnicode=true' in the connection string. To use 4-byte UTF8 with Connector/J configure the MySQL server with `character_set_server=utf8mb4'. Connector/J will then use that setting as long as `characterEncoding' has not been set in the connection string. This is equivalent to autodetection of the character set. (Bug #58232) * The `CallableStatementRegression' test suite failed with a Null Pointer Exception because the `OUT' parameter in the `I__S.PARAMETERS' table had no name, that is `COLUMN_NAME' had the value `NULL'. (Bug #58232) * `DatabaseMetaData.supportsMultipleResultSets()' was hard-coded to return `false', even though Connector/J supports multiple result sets. (Bug #57380) * Using the `useOldUTF8Behavior' parameter failed to set the connection character set to `latin1' as required. In versions prior to 5.1.3, the handshake was done using `latin1', and while there was logic in place to explicitly set the character set after the handshake was complete, this was bypassed when `useOldUTF8Behavior' was true. This was not a problem until 5.1.3, when the handshake was modified to use `utf8', but the logic continued to allow the character set configured during that handshake process to be retained for later use. As a result, `useOldUTF8Behavior' effectively failed. (Bug #57262) * Invoking a stored procedure containing output parameters by its full name, where the procedure was located in another database, generated the following exception: Parameter index of 1 is out of range (1, 0) (Bug #57022) * When a JDBC client disconnected from a remote server using `Connection.close()', the TCP connection remained in the `TIME_WAIT' state on the server side, rather than on the client side. (Bug #56979) * Leaving Trust/ClientCertStoreType properties unset caused an exception to be thrown when connecting with `useSSL=true', as no default was used. (Bug #56955) * When load-balanced connections swap servers, certain session state was copied from the previously active connection to the newly-selected connection. State synchronized included: * Auto-commit state * Transaction isolation state * Current schema/catalog However, the read-only state was not synchronized, which caused problems if a write was attempted on a read-only connection. (Bug #56706) * When using Connector/J configured for failover (jdbc:mysql://host1,host2,... URLs), the non-primary servers re-balanced when the transactions on the master were committed or rolled-back. (Bug #56429) * An unhandled Null Pointer Exception (NPE) was generated in `DatabaseMetaData.java' when calling an incorrectly cased function name where no permission to access `mysql.proc' was available. In addition to catching potential NPEs, a guard against calling JDBC functions with `db_name.proc_name' notation was also added. (Bug #56305) * Attempting to use JDBC4 functions on `Connection' objects resulted in errors being generated: Exception in thread "main" java.lang.AbstractMethodError: com.mysql.jdbc.LoadBalancedMySQLConnection.createBlob()Ljava/sql/Blob; at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at com.mysql.jdbc.LoadBalancingConnectionProxy.invoke(LoadBalancingConnectionProxy.java:476) at $Proxy0.createBlob(Unknown Source) (Bug #56099)  File: manual.info, Node: cj-news-5-1-13, Next: cj-news-5-1-12, Prev: cj-news-5-1-14, Up: cj-news-5-1 D.6.1.3 Changes in MySQL Connector/J 5.1.13 (24 June 2010) .......................................................... Fixes bugs found since release 5.1.12. *Functionality added or changed:* * Connector/J did not support `utf8mb4' for servers 5.5.2 and newer. Connector/J now auto-detects servers configured with `character_set_server=utf8mb4' or treats the Java encoding `utf-8' passed using `characterEncoding=...' as `utf8mb4' in the `SET NAMES=' calls it makes when establishing the connection. (Bug #54175) *Bugs fixed:* * The method `unSafeStatementInterceptors()' contained an erroneous line of code, which resulted in the interceptor being called, but the result being thrown away. (Bug #53041) * There was a performance regression of roughly 25% between r906 and r907, which appeared to be caused by pushing the Proxy down to the I/O layer. (Bug #52534) * Logic in implementations of `LoadBalancingConnectionProxy' and `LoadBalanceStrategy' behaved differently as to which `SQLException's trigger failover to a new host. The former looked at the first two characters of the SQLState: if (sqlState.startsWith("08")) ... The latter used a different test: if (sqlEx instanceof CommunicationsException || "08S01".equals(sqlEx.getSQLState())) { ... This meant it was possible for a new `Connection' object to throw an `Exception' when the first selected host was unavailable. This happened because `MySqlIO.createNewIO()' could throw an `SQLException' with a `SQLState' of `08001', which did not trigger the `try another host' logic in the `LoadBalanceStrategy' implementations, so an `Exception' was thrown after having only attempted connecting to a single host. (Bug #52231) * In the file `DatabaseMetadata.java', the function `private void getCallStmtParameterTypes' failed if the parameter was defined over more than one line by using the '\n' character. (Bug #52167) * The catalog parameter, `PARAM_CAT', was not correctly processed when calling for metadata with `getMetaData()' on stored procedures. This was because `PARAM_CAT' was hardcoded in the code to `NULL'. In the case where `nullcatalogmeanscurrent' was `true', which is its default value, a crash did not occur, but the metadata returned was for the stored procedures from the catalog currently attached to. If, however, `nullcatalogmeanscurrent' was set to `false' then a crash resulted. Connector/J has been changed so that when `NULL' is passed as `PARAM_CAT' it will not crash when `nullcatalogmeanscurrent' is `false', but rather iterate all catalogs in search of stored procedures. This means that `PARAM_CAT' is no longer hardcoded to `NULL' (see Bug #51904). (Bug #51912) * A load balanced `Connection' object with multiple open underlying physical connections rebalanced on `commit()', `rollback()', or on a communication exception, without validating the existing connection. This caused a problem when there was no pinging of the physical connections, using queries starting with `/* ping */', to ensure they remained active. This meant that calls to `Connection.commit()' could throw a `SQLException'. This did not occur when the transaction was actually committed; it occurred when the new connection was chosen and the driver attempted to set the auto-commit or transaction isolation state on the newly chosen physical connection. (Bug #51783) * The `rollback()' method could fail to rethrow a `SQLException' if the server became unavailable during a rollback. The errant code only rethrew when `ignoreNonTxTables' was true and the exception did not have the error code 1196, `SQLError.ER_WARNING_NOT_COMPLETE_ROLLBACK'. (Bug #51776) * When the `allowMultiQueries' connection string option was set to `true', a call to `Statement.executeBatch()' scanned the query for escape codes, even though `setEscapeProcessing(false)' had been called previously. (Bug #51704) * When a `StatementInterceptor' was used and an alternate `ResultSet' was returned from `preProcess()', the original statement was still executed. (Bug #51666) * Objects created by `ConnectionImpl', such as prepared statements, hold a reference to the `ConnectionImpl' that created them. However, when the load balancer picked a new connection, it did not update the reference contained in, for example, the `PreparedStatement'. This resulted in inserts and updates being directed to invalid connections, while commits were directed to the new connection. This resulted in silent data loss. (Bug #51643) * `jdbc:mysql:loadbalance://' would connect to the same host, even though `loadBalanceStrategy' was set to a value of `random', and multiple hosts were specified. (Bug #51266) * An unexpected exception when trying to register `OUT' parameters in `CallableStatement'. Sometimes Connector/J was not able to register `OUT' parameters for `CallableStatements'. (Bug #43576)  File: manual.info, Node: cj-news-5-1-12, Next: cj-news-5-1-11, Prev: cj-news-5-1-13, Up: cj-news-5-1 D.6.1.4 Changes in MySQL Connector/J 5.1.12 (18 February 2010) .............................................................. Fixes bugs found since release 5.1.11. *Bugs fixed:* * The catalog parameter was ignored in the `DatabaseMetaData.getProcedure()' method. It returned all procedures in all databases. (Bug #51022) * A call to `DatabaseMetaData.getDriverVersion()' returned the revision as `mysql-connector-java-5.1.11 ( Revision: ${svn.Revision} )'. The variable `${svn.Revision}' was not replaced by the SVN revision number. (Bug #50288)  File: manual.info, Node: cj-news-5-1-11, Next: cj-news-5-1-10, Prev: cj-news-5-1-12, Up: cj-news-5-1 D.6.1.5 Changes in MySQL Connector/J 5.1.11 (21 January 2010) ............................................................. Fixes bugs found since release 5.1.10. *Functionality added or changed:* * Replication connections, those with URLs that start with jdbc:mysql:replication, now use a jdbc:mysql:loadbalance connection for the slave pool. This means that it is possible to set load balancing properties such as `loadBalanceBlacklistTimeout' and `loadBalanceStrategy' to choose a mechanism for balancing the load, and failover or fault tolerance strategy for the slave pool. (Bug #49537) *Bugs fixed:* * `NullPointerException' sometimes occurred in `invalidateCurrentConnection()' for load-balanced connections. (Bug #50288) * The `deleteRow' method caused a full table scan, when using an updatable cursor and a multibyte character set. (Bug #49745) * For pooled connections, Connector/J did not process the session variable `time_zone' when set using the URL, resulting in incorrect timestamp values being stored. (Bug #49700) * The `ExceptionInterceptor' class did not provide a `Connection' context. (Bug #49607) * Ping left closed connections in the liveConnections map, causing subsequent Exceptions when that connection was used. (Bug #48605) * Using `MysqlConnectionPoolDataSource' with a load-balanced URL generated exceptions of type `ClassCastException': ClassCastException in MysqlConnectionPoolDataSource Caused by: java.lang.ClassCastException: $Proxy0 at com.mysql.jdbc.jdbc2.optional.MysqlConnectionPoolDataSource.getPooledConnection(MysqlConne ctionPoolDataSource.java:80) java.lang.ClassCastException: $Proxy2 at com.mysql.jdbc.jdbc2.optional.StatementWrapper.executeQuery(StatementWrapper.java:744) (Bug #48486) * The implementation for load-balanced `Connection' used a proxy, which delegated method calls, including `equals()' and `hashCode()', to underlying `Connection' objects. This meant that successive calls to `hashCode()' on the same object potentially returned different values, if the proxy state had changed such that it was utilizing a different underlying connection. (Bug #48442) * The batch rewrite functionality attempted to identify the start of the `VALUES' list by looking for `VALUES ' (with trailing space). However, valid MySQL syntax permits `VALUES' to be followed by whitespace or an opening parenthesis: INSERT INTO tbl VALUES (1); INSERT INTO tbl VALUES(1); Queries written with the above formats did not therefore gain the performance benefits of the batch rewrite. (Bug #48172) * A PermGen memory leaked was caused by the Connector/J statement cancellation timer (`java.util.Timer'). When the application was unloaded the cancellation timer did not terminate, preventing the ClassLoader from being garbage collected. (Bug #36565) * With the connection string option `noDatetimeStringSync' set to `true', and server-side prepared statements enabled, the following exception was generated if an attempt was made to obtain, using `ResultSet.getString()', a datetime value containing all zero components: java.sql.SQLException: Value '0000-00-00' can not be represented as java.sql.Date (Bug #32525)  File: manual.info, Node: cj-news-5-1-10, Next: cj-news-5-1-9, Prev: cj-news-5-1-11, Up: cj-news-5-1 D.6.1.6 Changes in MySQL Connector/J 5.1.10 (23 September 2009) ............................................................... Fixes bugs found since release 5.1.9. *Bugs fixed:* * The `DriverManager.getConnection()' method ignored a non-standard port if it was specified in the JDBC connection string. Connector/J always used the standard port 3306 for connection creation. For example, if the string was `jdbc:mysql://localhost:6777', Connector/J would attempt to connect to port 3306, rather than 6777. (Bug #47494)  File: manual.info, Node: cj-news-5-1-9, Next: cj-news-5-1-8, Prev: cj-news-5-1-10, Up: cj-news-5-1 D.6.1.7 Changes in MySQL Connector/J 5.1.9 (21 September 2009) .............................................................. *Bugs fixed:* * In the class `com.mysql.jdbc.jdbc2.optional.SuspendableXAConnection', which is used when `pinGlobalTxToPhysicalConnection=true', there is a static map (XIDS_TO_PHYSICAL_CONNECTIONS) that tracks the Xid with the XAConnection, however this map was not populated. The effect was that the `SuspendableXAConnection' was never pinned to the real XA connection. Instead it created new connections on calls to `start', `end', `resume', and `prepare'. (Bug #46925) * When using the ON DUPLICATE KEY UPDATE functionality together with the rewriteBatchedStatements option set to true, an exception was generated when trying to execute the prepared statement: INSERT INTO config_table (modified,id_) VALUES (?,?) ON DUPLICATE KEY UPDATE modified=? The exception generated was: java.sql.SQLException: Parameter index out of range (3 > number of parameters, which is 2). at com.sag.etl.job.processors.JdbcInsertProcessor.flush(JdbcInsertProcessor.java:135) ...... Caused by: java.sql.SQLException: Parameter index out of range (3 > number of parameters, which is 2). at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1055) at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:956) at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:926) at com.mysql.jdbc.PreparedStatement.checkBounds(PreparedStatement.java:3657) at com.mysql.jdbc.PreparedStatement.setInternal(PreparedStatement.java:3641) at com.mysql.jdbc.PreparedStatement.setBytesNoEscapeNoQuotes(PreparedStatement.java:3391) at com.mysql.jdbc.PreparedStatement.setOneBatchedParameterSet(PreparedStatement.java:4203) at com.mysql.jdbc.PreparedStatement.executeBatchedInserts(PreparedStatement.java:1759) at com.mysql.jdbc.PreparedStatement.executeBatch(PreparedStatement.java:1441) at com.sag.etl.job.processors.JdbcInsertProcessor.flush(JdbcInsertProcessor.java:131) ... 16 more (Bug #46788) * When Connector/J encountered an error condition that caused it to create a `CommunicationsException', it tried to build a friendly error message that helped diagnose what was wrong. However, if there had been no network packets received from the server, the error message contained the following incorrect text: The last packet successfully received from the server was 1,249,932,468,916 milliseconds ago. The last packet sent successfully to the server was 0 milliseconds ago. (Bug #46637) * The `getSuperTypes' method returned a result set with incorrect names for the first two columns. The name of the first column in the result set was expected to be `TYPE_CAT' and that of the second column `TYPE_SCHEM'. The method however returned the names as `TABLE_CAT' and `TABLE_SCHEM' for first and second column respectively. (Bug #44508) * SQLException for data truncation error gave the error code as 0 instead of 1265. (Bug #44324) * Calling `ResultSet.deleteRow()' on a table with a primary key of type `BINARY(8)' silently failed to delete the row, but only in some repeatable cases. The generated `DELETE' statement generated corrupted part of the primary key data. Specifically, one of the bytes was changed from 0x90 to 0x9D, although the corruption appeared to be different depending on whether the application was run on Windows or Linux. (Bug #43759) * Accessing result set columns by name after the result set had been closed resulted in a NullPointerException instead of a SQLException. (Bug #41484) * `QueryTimeout' did not work for batch statements waiting on a locked table. When a batch statement was issued to the server and was forced to wait because of a locked table, Connector/J only terminated the first statement in the batch when the timeout was exceeded, leaving the rest hanging. (Bug #34555) * The `parseURL' method in class `com.mysql.jdbc.Driver' did not work as expected. When given a URL such as `jdbc:mysql://www.mysql.com:12345/my_database' to parse, the property `PORT_PROPERTY_KEY' was found to be `null' and the `HOST_PROPERTY_KEY' property was found to be `www.mysql.com:12345'. *Note*: Connector/J has been fixed so that it will now always fill in the `PORT' property (using 3306 if not specified), and the `HOST' property (using `localhost' if not specified) when `parseURL()' is called. The driver also parses a list of hosts into `HOST.n' and `PORT.n' properties as well as adding a property `NUM_HOSTS' for the number of hosts it has found. If a list of hosts is passed to the driver, `HOST' and `PORT' will be set to the values given by `HOST.1' and `PORT.1' respectively. This change has centralized and cleaned up a large section of code used to generate lists of hosts, both for load-balanced and fault tolerant connections and their tests. (Bug #32216) * Attempting to delete rows using `ResultSet.deleteRow()' did not delete rows correctly. (Bug #27431) * The `setDate' method silently ignored the Calendar parameter. The code was implemented as follows: public void setDate(int parameterIndex, java.sql.Date x, Calendar cal) throws SQLException { setDate(parameterIndex, x); } From reviewing the code it was apparent that the Calendar parameter `cal' was ignored. (Bug #23584)  File: manual.info, Node: cj-news-5-1-8, Next: cj-news-5-1-7, Prev: cj-news-5-1-9, Up: cj-news-5-1 D.6.1.8 Changes in MySQL Connector/J 5.1.8 (16 July 2009) ......................................................... *Bugs fixed:* * The reported milliseconds since the last server packets were received/sent was incorrect by a factor of 1000. For example, the following method call: SQLError.createLinkFailureMessageBasedOnHeuristics( (ConnectionImpl) this.conn, System.currentTimeMillis() - 1000, System.currentTimeMillis() - 2000, e, false); returned the following string: The last packet successfully received from the server was 2 milliseconds ago. The last packet sent successfully to the server was 1 milliseconds ago. (Bug #45419) * Calling `Connection.serverPrepareStatement()' variants that do not take result set type or concurrency arguments returned statements that produced result sets with incorrect defaults, namely `TYPE_SCROLL_SENSITIVE'. (Bug #45171) * The result set returned by `getIndexInfo()' did not have the format defined in the JDBC API specifications. The fourth column, `DATA_TYPE', of the result set should be of type `BOOLEAN'. Connector/J however returns `CHAR'. (Bug #44869) * The result set returned by `getTypeInfo()' did not have the format defined in the JDBC API specifications. The second column, `DATA_TYPE', of the result set should be of type `INTEGER'. Connector/J however returns `SMALLINT'. (Bug #44868) * The `DEFERRABILITY' column in database metadata result sets was expected to be of type `SHORT'. However, Connector/J returned it as `INTEGER'. This affected the following methods: `getImportedKeys()', `getExportedKeys()', `getCrossReference()'. (Bug #44867) * The result set returned by `getColumns()' did not have the format defined in the JDBC API specifications. The fifth column, `DATA_TYPE', of the result set should be of type `INTEGER'. Connector/J however returns `SMALLINT'. (Bug #44865) * The result set returned by `getVersionColumns()' did not have the format defined in the JDBC API specifications. The third column, `DATA_TYPE', of the result set should be of type `INTEGER'. Connector/J however returns `SMALLINT'. (Bug #44863) * The result set returned by `getBestRowIdentifier()' did not have the format defined in the JDBC API specifications. The third column, `DATA_TYPE', of the result set should be of type `INTEGER'. Connector/J however returns `SMALLINT'. (Bug #44862) * Connector/J contains logic to generate a message text specifically for streaming result sets when there are `CommunicationsException' exceptions generated. However, this code was never reached. In the `CommunicationsException' code: private boolean streamingResultSetInPlay = false; public CommunicationsException(ConnectionImpl conn, long lastPacketSentTimeMs, long lastPacketReceivedTimeMs, Exception underlyingException) { this.exceptionMessage = SQLError.createLinkFailureMessageBasedOnHeuristics(conn, lastPacketSentTimeMs, lastPacketReceivedTimeMs, underlyingException, this.streamingResultSetInPlay); `streamingResultSetInPlay' was always false, which in the following code in `SQLError.createLinkFailureMessageBasedOnHeuristics()' never being executed: if (streamingResultSetInPlay) { exceptionMessageBuf.append( Messages.getString("CommunicationsException.ClientWasStreaming")); //$NON-NLS-1$ } else { ... (Bug #44588) * The `SQLError.createLinkFailureMessageBasedOnHeuristics()' method created a message text for communication link failures. When certain conditions were met, this message included both `last packet sent' and `last packet received' information, but when those conditions were not met, only `last packet sent' information was provided. Information about when the last packet was successfully received should be provided in all cases. (Bug #44587) * `Statement.getGeneratedKeys()' retained result set instances until the statement was closed. This caused memory leaks for long-lived statements, or statements used in tight loops. (Bug #44056) * Using `useInformationSchema' with `DatabaseMetaData.getExportedKeys()' generated the following exception: com.mysql.jdbc.exceptions.MySQLIntegrityConstraintViolationException: Column 'REFERENCED_TABLE_NAME' in where clause is ambiguous ... at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:1772) at com.mysql.jdbc.PreparedStatement.executeQuery(PreparedStatement.java:1923) at com.mysql.jdbc.DatabaseMetaDataUsingInfoSchema.executeMetadataQuery( DatabaseMetaDataUsingInfoSchema.java:50) at com.mysql.jdbc.DatabaseMetaDataUsingInfoSchema.getExportedKeys( DatabaseMetaDataUsingInfoSchema.java:603) (Bug #43714) * `LoadBalancingConnectionProxy.doPing()' did not have blacklist awareness. `LoadBalancingConnectionProxy' implemented `doPing()' to ping all underlying connections, but it threw any exceptions it encountered during this process. With the global blacklist enabled, it catches these exceptions, adds the host to the global blacklist, and only throws an exception if all hosts are down. (Bug #43421) * The method `Statement.getGeneratedKeys()' did not return values for `UNSIGNED BIGINTS' with values greater than `Long.MAX_VALUE'. Unfortunately, because the server does not tell clients what TYPE the auto increment value is, the driver cannot consistently return BigIntegers for the result set returned from `getGeneratedKeys()', it will only return them if the value is greater than `Long.MAX_VALUE'. If your application needs this consistency, it will need to check the class of the return value from `.getObject()' on the ResultSet returned by `Statement.getGeneratedKeys()' and if it is not a BigInteger, create one based on the `java.lang.Long' that is returned. (Bug #43196) * When the MySQL Server was upgraded from 4.0 to 5.0, the Connector/J application then failed to connect to the server. This was because authentication failed when the application ran from EBCDIC platforms such as z/OS. (Bug #43071) * When connecting with `traceProtocol=true', no trace data was generated for the server greeting or login request. (Bug #43070) * Connector/J generated an unhandled `StringIndexOutOfBoundsException': java.lang.StringIndexOutOfBoundsException: String index out of range: -1 at java.lang.String.substring(String.java:1938) at com.mysql.jdbc.EscapeProcessor.processTimeToken(EscapeProcessor.java:353) at com.mysql.jdbc.EscapeProcessor.escapeSQL(EscapeProcessor.java:257) at com.mysql.jdbc.StatementImpl.executeUpdate(StatementImpl.java:1546) at com.mysql.jdbc.StatementImpl.executeUpdate(StatementImpl.java:1524) (Bug #42253) * A `ConcurrentModificationException' was generated in `LoadBalancingConnectionProxy': java.util.ConcurrentModificationException at java.util.HashMap$HashIterator.nextEntry(Unknown Source) at java.util.HashMap$KeyIterator.next(Unknown Source) at com.mysql.jdbc.LoadBalancingConnectionProxy.getGlobalBlacklist(LoadBalancingConnectionProxy.java:520) at com.mysql.jdbc.RandomBalanceStrategy.pickConnection(RandomBalanceStrategy.java:55) at com.mysql.jdbc.LoadBalancingConnectionProxy.pickNewConnection(LoadBalancingConnectionProxy.java:414) at com.mysql.jdbc.LoadBalancingConnectionProxy.invoke(LoadBalancingConnectionProxy.java:390) (Bug #42055) * SQL injection was possible when using a string containing U+00A5 in a client-side prepared statement, and the character set being used was SJIS/Windows-31J. (Bug #41730) * If there was an apostrophe in a comment in a statement that was being sent through Connector/J, the apostrophe was still recognized as a quote and put the state machine in `EscapeTokenizer' into the `inQuotes' state. This led to further parse errors. For example, consider the following statement: String sql = "-- Customer's zip code will be fixed\n" + "update address set zip_code = 99999\n" + "where not regexp '^[0-9]{5}([[.-.]])?([0-9]{4})?$'"; When passed through Connector/J, the `EscapeTokenizer' did not recognize that the first apostrophe was in a comment and thus set `inQuotes' to true. When that happened, the quote count was incorrect and thus the regular expression did not appear to be in quotation marks. With the parser not detecting that the regular expression was in quotation marks, the curly braces were recognized as escape sequences and were removed from the regular expression, breaking it. The server thus received SQL such as: -- Customer's zip code will be fixed update address set zip_code = '99999' where not regexp '^[0-9]([[.-.]])?([0-9])?$' (Bug #41566) * MySQL Connector/J 5.1.7 was slower than previous versions when the `rewriteBatchedStatements' option was set to `true'. *Note*: The performance regression in `indexOfIgnoreCaseRespectMarker()'has been fixed. It has also been made possible for the driver to rewrite `INSERT' statements with `ON DUPLICATE KEY UPDATE' clauses in them, as long as the `UPDATE' clause contains no reference to `LAST_INSERT_ID()', as that would cause the driver to return bogus values for `getGeneratedKeys()' invocations. This has resulted in improved performance over version 5.1.7. (Bug #41532) * When accessing a result set column by name using `ResultSetImpl.findColumn()' an exception was generated: java.lang.NullPointerException at com.mysql.jdbc.ResultSetImpl.findColumn(ResultSetImpl.java:1103) at com.mysql.jdbc.ResultSetImpl.getShort(ResultSetImpl.java:5415) at org.apache.commons.dbcp.DelegatingResultSet.getShort(DelegatingResultSet.java:219) at com.zimbra.cs.db.DbVolume.constructVolume(DbVolume.java:297) at com.zimbra.cs.db.DbVolume.get(DbVolume.java:197) at com.zimbra.cs.db.DbVolume.create(DbVolume.java:95) at com.zimbra.cs.store.Volume.create(Volume.java:227) at com.zimbra.cs.store.Volume.create(Volume.java:189) at com.zimbra.cs.service.admin.CreateVolume.handle(CreateVolume.java:48) at com.zimbra.soap.SoapEngine.dispatchRequest(SoapEngine.java:428) at com.zimbra.soap.SoapEngine.dispatch(SoapEngine.java:285) (Bug #41484) * The `RETURN_GENERATED_KEYS' flag was being ignored. For example, in the following code the `RETURN_GENERATED_KEYS' flag was ignored: PreparedStatement ps = connection.prepareStatement("INSERT INTO table values(?,?)",PreparedStatement.RETURN_GENERATED_KEYS); (Bug #41448) * When using Connector/J 5.1.7 to connect to MySQL Server 4.1.18 the following error message was generated: Thu Dec 11 17:38:21 PST 2008 WARN: Invalid value {1} for server variable named {0}, falling back to sane default of {2} This occurred with MySQL Server version that did not support `auto_increment_increment'. The error message should not have been generated. (Bug #41416) * When `DatabaseMetaData.getProcedureColumns()' was called, the value for `LENGTH' was always returned as 65535, regardless of the column type (fixed or variable) or the actual length of the column. However, if you obtained the `PRECISION' value, this was correct for both fixed and variable length columns. (Bug #41269) * `PreparedStatement.addBatch()' did not check for all parameters being set, which led to inconsistent behavior in `executeBatch()', especially when rewriting batched statements into multi-value `INSERT's. (Bug #41161) * Error message strings contained variable values that were not expanded. For example: Mon Nov 17 11:43:18 JST 2008 WARN: Invalid value {1} for server variable named {0}, falling back to sane default of {2} (Bug #40772) * When using `rewriteBatchedStatements=true' with: INSERT INTO table_name_values (...) VALUES (...) Query rewriting failed because `values' at the end of the table name was mistaken for the reserved keyword. The error generated was as follows: testBug40439(testsuite.simple.TestBug40439)java.sql.BatchUpdateException: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'values (2,'toto',2),(id,data, ordr) values (3,'toto',3),(id,data, ordr) values (' at line 1 at com.mysql.jdbc.PreparedStatement.executeBatchedInserts(PreparedStatement.java:1495) at com.mysql.jdbc.PreparedStatement.executeBatch(PreparedStatement.java:1097) at testsuite.simple.TestBug40439.testBug40439(TestBug40439.java:42) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at testsuite.simple.TestBug40439.main(TestBug40439.java:57) (Bug #40439) * A statement interceptor received the incorrect parameters when used with a batched statement. (Bug #39426) * Using Connector/J 5.1.6 the method `ResultSet.getObject' returned a `BYTE[]' for following: SELECT TRIM(rowid) FROM tbl Where `rowid' had a type of `INT(11) PRIMARY KEY AUTO_INCREMENT'. The expected return type was one of `CHAR', `VARCHAR', `CLOB', however, a `BYTE[]' was returned. Further, adding `functionsNeverReturnBlobs=true' to the connection string did not have any effect on the return type. (Bug #38387)  File: manual.info, Node: cj-news-5-1-7, Next: cj-news-5-1-6, Prev: cj-news-5-1-8, Up: cj-news-5-1 D.6.1.9 Changes in MySQL Connector/J 5.1.7 (21 October 2008) ............................................................ *Functionality added or changed:* * When statements include `ON DUPLICATE UPDATE', and `rewriteBatchedStatements' is set to true, batched statements are not rewritten into the form `INSERT INTO table VALUES (), (), ()', instead the statements are executed sequentially. *Bugs fixed:* * `Statement.getGeneratedKeys()' returned two keys when using `ON DUPLICATE KEY UPDATE' and the row was updated, not inserted. (Bug #42309) * When using the replication driver with `autoReconnect=true', Connector/J checks in `PreparedStatement.execute' (also called by `CallableStatement.execute') to determine if the first character of the statement is an `S', in an attempt to block all statements that are not read-only-safe, for example non-*Note `SELECT': select. statements. However, this also blocked *Note `CALL': call.s to stored procedures, even if the stored procedures were defined as `SQL READ DATA' or `NO SQL'. (Bug #40031) * With large result sets `ResultSet.findColumn' became a performance bottleneck. (Bug #39962) * Connector/J ignored the value of the MySQL Server variable `auto_increment_increment'. (Bug #39956) * Connector/J failed to parse *Note `TIMESTAMP': datetime. strings for nanos correctly. (Bug #39911) * When the `LoadBalancingConnectionProxy' handles a `SQLException' with SQL state starting with `08', it calls `invalidateCurrentConnection', which in turn removes that `Connection' from `liveConnections' and the `connectionsToHostsMap', but it did not add the host to the new global blacklist, if the global blacklist was enabled. There was also the possibility of a `NullPointerException' when trying to update stats, where `connectionsToHostsMap.get(this.currentConn)' was called: int hostIndex = ((Integer) this.hostsToListIndexMap.get(this.connectionsToHostsMap.get(this.currentConn))).intValue(); This could happen if a client tried to issue a rollback after catching a `SQLException' caused by a connection failure. (Bug #39784) * When configuring the Java Replication Driver the last slave specified was never used. (Bug #39611) * When an `INSERT ON DUPLICATE KEY UPDATE' was performed, and the key already existed, the `affected-rows' value was returned as 1 instead of 0. (Bug #39352) * When using the random load balancing strategy and starting with two servers that were both unavailable, an `IndexOutOfBoundsException' was generated when removing a server from the `whiteList'. (Bug #38782) * Connector/J threw the following exception when using a read-only connection: java.sql.SQLException: Connection is read-only. Queries leading to data modification are not allowed. (Bug #38747) * Connector/J was unable to connect when using a non-`latin1' password. (Bug #37570) * The `useOldAliasMetadataBehavior' connection property was ignored. (Bug #35753) * Incorrect result is returned from `isAfterLast()' in streaming `ResultSet' when using `setFetchSize(Integer.MIN_VALUE)'. (Bug #35170) * When `getGeneratedKeys()' was called on a statement that had not been created with `RETURN_GENERATED_KEYS', no exception was thrown, and batched executions then returned erroneous values. (Bug #34185) * The `loadBalance' `bestResponseTime' blacklists did not have a global state. (Bug #33861)  File: manual.info, Node: cj-news-5-1-6, Next: cj-news-5-1-5, Prev: cj-news-5-1-7, Up: cj-news-5-1 D.6.1.10 Changes in MySQL Connector/J 5.1.6 (07 March 2008) ........................................................... *Functionality added or changed:* * Multiple result sets were not supported when using streaming mode to return data. Both normal statements and the resul sets from stored procedures now return multiple results sets, with the exception of result sets using registered `OUTPUT' parameters. (Bug #33678) * XAConnections and datasources have been updated to the JDBC-4.0 standard. * The profiler event handling has been made extensible using the `profilerEventHandler' connection property. * Add the `verifyServerCertificate' property. If set to "false" the driver will not verify the server's certificate when `useSSL' is set to "true" When using this feature, the keystore parameters should be specified by the `clientCertificateKeyStore*' properties, rather than system properties, as the JSSE doesn't it straightforward to have a nonverifying trust store and the "default" key store. *Bugs fixed:* * DatabaseMetaData.getColumns() returns incorrect `COLUMN_SIZE' value for `SET' column. (Bug #36830) * When trying to read Time values like `00:00:00' with ResultSet.getTime(int) an exception is thrown. (Bug #36051) * JDBC connection URL parameters is ignored when using `MysqlConnectionPoolDataSource'. (Bug #35810) * When `useServerPrepStmts=true' and slow query logging is enabled, the connector throws a NullPointerException when it encounters a slow query. (Bug #35666) * When using the keyword `loadbalance' in the connection string and trying to perform load balancing between two databases, the driver appears to hang. (Bug #35660) * JDBC data type getter method was changed to accept only column name, whereas previously it accepted column label. (Bug #35610) * Prepared statements from pooled connections caused a NullPointerException when closed() under JDBC-4.0. (Bug #35489) * In calling a stored function returning a `bigint', an exception is encountered beginning: java.sql.SQLException: java.lang.NumberFormatException: For input string: followed by the text of the stored function starting after the argument list. (Bug #35199) * The JDBC driver uses a different method for evaluating column names in resultsetmetadata.getColumnName() and when looking for a column in resultset.getObject(columnName). This causes Hibernate to fail in queries where the two methods yield different results, for example in queries that use alias names: SELECT column AS aliasName from table (Bug #35150) * `MysqlConnectionPoolDataSource' does not support `ReplicationConnection'. Notice that we implemented `com.mysql.jdbc.Connection' for `ReplicationConnection', however, only accessors from ConnectionProperties are implemented (not the mutators), and they return values from the currently active connection. All other methods from `com.mysql.jdbc.Connection' are implemented, and operate on the currently active connection, with the exception of `resetServerState()' and `changeUser()'. (Bug #34937) * `ResultSet.getTimestamp()' returns incorrect values for month/day of *Note `TIMESTAMP': datetime.s when using server-side prepared statements (not enabled by default). (Bug #34913) * RowDataStatic does't always set the metadata in ResultSetRow, which can lead to failures when unpacking *Note `DATE': datetime, *Note `TIME': time, *Note `DATETIME': datetime. and *Note `TIMESTAMP': datetime. types when using absolute, relative, and previous result set navigation methods. (Bug #34762) * When calling `isValid()' on an active connection, if the timeout is nonzero then the `Connection' is invalidated even if the `Connection' is valid. (Bug #34703) * It was not possible to truncate a *Note `BLOB': blob. using `Blog.truncate()' when using 0 as an argument. (Bug #34677) * When using a cursor fetch for a statement, the internal prepared statement could cause a memory leak until the connection was closed. The internal prepared statement is now deleted when the corresponding result set is closed. (Bug #34518) * When retrieving the column type name of a geometry field, the driver would return `UNKNOWN' instead of `GEOMETRY'. (Bug #34194) * Statements with batched values do not return correct values for `getGeneratedKeys()' when `rewriteBatchedStatements' is set to `true', and the statement has an `ON DUPLICATE KEY UPDATE' clause. (Bug #34093) * The internal class ResultSetInternalMethods referenced the nonpublic class com.mysql.jdbc.CachedResultSetMetaData. (Bug #33823) * A `NullPointerException' could be raised when using client-side prepared statements and enabled the prepared statement cache using the `cachePrepStmts'. (Bug #33734) * Using server side cursors and cursor fetch, the table metadata information would return the data type name instead of the column name. (Bug #33594) * ResultSet.getTimestamp() would throw a `NullPointerException' instead of a `SQLException' when called on an empty `ResultSet'. (Bug #33162) * Load balancing connection using best response time would incorrectly "stick" to hosts that were down when the connection was first created. We solve this problem with a black list that is used during the picking of new hosts. If the black list ends up including all configured hosts, the driver will retry for a configurable number of times (the `retriesAllDown' configuration property, with a default of 120 times), sleeping 250ms between attempts to pick a new connection. We've also went ahead and made the balancing strategy extensible. To create a new strategy, implement the interface com.mysql.jdbc.BalanceStrategy (which also includes our standard "extension" interface), and tell the driver to use it by passing in the class name using the `loadBalanceStrategy' configuration property. (Bug #32877) * During a Daylight Savings Time (DST) switchover, there was no way to store two timestamp/datetime values , as the hours end up being the same when sent as the literal that MySQL requires. Note that to get this scenario to work with MySQL (since it doesn't support per-value timezones), you need to configure your server (or session) to be in UTC, and tell the driver not to use the legacy date/time code by setting `useLegacyDatetimeCode' to "false". This will cause the driver to always convert to/from the server and client timezone consistently. This bug fix also fixes BUG#15604, by adding entirely new date/time handling code that can be switched on by `useLegacyDatetimeCode' being set to "false" as a JDBC configuration property. For Connector/J 5.1.x, the default is "true", in trunk and beyond it will be "false" (that is, the old date/time handling code will be deprecated) (Bug #32577, Bug #15604) * When unpacking rows directly, we don't hand off error message packets to the internal method which decodes them correctly, so no exception is raised, and the driver than hangs trying to read rows that aren't there. This tends to happen when calling stored procedures, as normal SELECTs won't have an error in this spot in the protocol unless an I/O error occurs. (Bug #32246) * When using a connection from ConnectionPoolDataSource, some `Connection.prepareStatement()' methods would return null instead of the prepared statement. (Bug #32101) * Using `CallableStatement.setNull()' on a stored function would throw an `ArrayIndexOutOfBounds' exception when setting the last parameter to null. (Bug #31823) * MysqlValidConnectionChecker doesn't properly handle connections created using ReplicationConnection. (Bug #31790) * Retrieving the server version information for an active connection could return invalid information if the default character encoding on the host was not ASCII compatible. (Bug #31192) * Further fixes have been made to this bug in the event that a node is nonresponsive. Connector/J will now try a different random node instead of waiting for the node to recover before continuing. (Bug #31053) * `ResultSet' returned by `Statement.getGeneratedKeys()' is not closed automatically when statement that created it is closed. (Bug #30508) * `DatabaseMetadata.getColumns()' doesn't return the correct column names if the connection character isn't UTF-8. A bug in MySQL server compounded the issue, but was fixed within the MySQL 5.0 release cycle. The fix includes changes to all the sections of the code that access the server metadata. (Bug #20491) * Fixed ResultSetMetadata.getColumnName() for result sets returned from Statement.getGeneratedKeys() - it was returning null instead of "GENERATED_KEY" as in 5.0.x.  File: manual.info, Node: cj-news-5-1-5, Next: cj-news-5-1-4, Prev: cj-news-5-1-6, Up: cj-news-5-1 D.6.1.11 Changes in MySQL Connector/J 5.1.5 (09 October 2007) ............................................................. *The following features are new, compared to the 5.0 series of Connector/J* * Support for JDBC-4.0 *Note `NCHAR': char, *Note `NVARCHAR': char. and `NCLOB' types. * JDBC-4.0 support for setting per-connection client information (which can be viewed in the comments section of a query using *Note `SHOW PROCESSLIST': show-processlist. on a MySQL server, or can be extended to support custom persistence of the information using a public interface). * Support for JDBC-4.0 XML processing using JAXP interfaces to DOM, SAX and StAX. * JDBC-4.0 standardized unwrapping to interfaces that include vendor extensions. *Functionality added or changed:* * Added `autoSlowLog' configuration property, overrides `slowQueryThreshold*' properties, driver determines slow queries by those that are slower than 5 * stddev of the mean query time (outside the 96% percentile). *Bugs fixed:* * When a connection is in read-only mode, queries that are wrapped in parentheses were incorrectly identified DML statements. (Bug #28256) * When calling `setTimestamp' on a prepared statement, the timezone information stored in the calendar object was ignored. This resulted in the incorrect `DATETIME' information being stored. The following example illustrates this: Timestamp t = new Timestamp( cal.getTimeInMillis() ); ps.setTimestamp( N, t, cal ); (Bug #15604)  File: manual.info, Node: cj-news-5-1-4, Next: cj-news-5-1-3, Prev: cj-news-5-1-5, Up: cj-news-5-1 D.6.1.12 Changes in MySQL Connector/J 5.1.4 (Not Released) .......................................................... Only released internally. This section has no changelog entries.  File: manual.info, Node: cj-news-5-1-3, Next: cj-news-5-1-2, Prev: cj-news-5-1-4, Up: cj-news-5-1 D.6.1.13 Changes in MySQL Connector/J 5.1.3 (10 September 2007) ............................................................... *The following features are new, compared to the 5.0 series of Connector/J* * Support for JDBC-4.0 *Note `NCHAR': char, *Note `NVARCHAR': char. and `NCLOB' types. * JDBC-4.0 support for setting per-connection client information (which can be viewed in the comments section of a query using *Note `SHOW PROCESSLIST': show-processlist. on a MySQL server, or can be extended to support custom persistence of the information using a public interface). * Support for JDBC-4.0 XML processing using JAXP interfaces to DOM, SAX and StAX. * JDBC-4.0 standardized unwrapping to interfaces that include vendor extensions. *Functionality added or changed:* * Connector/J now connects using an initial character set of `utf-8' solely for the purpose of authentication to permit user names or database names in any character set to be used in the JDBC connection URL. (Bug #29853) * Added two configuration parameters: * `blobsAreStrings': Should the driver always treat BLOBs as Strings. Added specifically to work around dubious metadata returned by the server for `GROUP BY' clauses. Defaults to false. * `functionsNeverReturnBlobs': Should the driver always treat data from functions returning `BLOBs' as Strings. Added specifically to work around dubious metadata returned by the server for `GROUP BY' clauses. Defaults to false. * Setting `rewriteBatchedStatements' to `true' now causes CallableStatements with batched arguments to be re-written in the form "CALL (...); CALL (...); ..." to send the batch in as few client/server round trips as possible. * The driver now picks appropriate internal row representation (whole row in one buffer, or individual byte[]s for each column value) depending on heuristics, including whether or not the row has *Note `BLOB': blob. or *Note `TEXT': blob. types and the overall row-size. The threshold for row size that will cause the driver to use a buffer rather than individual byte[]s is configured by the configuration property `largeRowSizeThreshold', which has a default value of 2KB. * The data (and how it is stored) for `ResultSet' rows are now behind an interface which enables us (in some cases) to allocate less memory per row, in that for "streaming" result sets, we re-use the packet used to read rows, since only one row at a time is ever active. * Added experimental support for statement "interceptors" through the `com.mysql.jdbc.StatementInterceptor' interface, examples are in `com/mysql/jdbc/interceptors'. Implement this interface to be placed "in between" query execution, so that it can be influenced (currently experimental). * The driver will automatically adjust the server session variable `net_write_timeout' when it determines its been asked for a "streaming" result, and resets it to the previous value when the result set has been consumed. (The configuration property is named `netTimeoutForStreamingResults', with a unit of seconds, the value '0' means the driver will not try and adjust this value). * JDBC-4.0 ease-of-development features including auto-registration with the `DriverManager' through the service provider mechanism, standardized Connection validity checks and categorized `SQLExceptions' based on recoverability/retry-ability and class of the underlying error. * `Statement.setQueryTimeout()'s now affect the entire batch for batched statements, rather than the individual statements that make up the batch. * Errors encountered during `Statement'/`PreparedStatement'/`CallableStatement.executeBatch()' when `rewriteBatchStatements' has been set to `true' now return `BatchUpdateExceptions' according to the setting of `continueBatchOnError'. If `continueBatchOnError' is set to `true', the update counts for the "chunk" that were sent as one unit will all be set to `EXECUTE_FAILED', but the driver will attempt to process the remainder of the batch. You can determine which "chunk" failed by looking at the update counts returned in the `BatchUpdateException'. If `continueBatchOnError' is set to "false", the update counts returned will contain all updates up-to and including the failed "chunk", with all counts for the failed "chunk" set to `EXECUTE_FAILED'. Since MySQL doesn't return multiple error codes for multiple-statements, or for multi-value *Note `INSERT': insert./*Note `REPLACE': replace, it is the application's responsibility to handle determining which item(s) in the "chunk" actually failed. * New methods on com.mysql.jdbc.Statement: `setLocalInfileInputStream()' and `getLocalInfileInputStream()': * `setLocalInfileInputStream()' sets an `InputStream' instance that will be used to send data to the MySQL server for a *Note `LOAD DATA LOCAL INFILE': load-data. statement rather than a `FileInputStream' or `URLInputStream' that represents the path given as an argument to the statement. This stream will be read to completion upon execution of a *Note `LOAD DATA LOCAL INFILE': load-data. statement, and will automatically be closed by the driver, so it needs to be reset before each call to `execute*()' that would cause the MySQL server to request data to fulfill the request for *Note `LOAD DATA LOCAL INFILE': load-data. If this value is set to `NULL', the driver will revert to using a `FileInputStream' or `URLInputStream' as required. * `getLocalInfileInputStream()' returns the `InputStream' instance that will be used to send data in response to a *Note `LOAD DATA LOCAL INFILE': load-data. statement. This method returns `NULL' if no such stream has been set using `setLocalInfileInputStream()'. * Setting `useBlobToStoreUTF8OutsideBMP' to `true' tells the driver to treat `[MEDIUM/LONG]BLOB' columns as `[LONG]VARCHAR' columns holding text encoded in UTF-8 that has characters outside the BMP (4-byte encodings), which MySQL server can't handle natively. Set `utf8OutsideBmpExcludedColumnNamePattern' to a regex so that column names matching the given regex will still be treated as `BLOBs' The regex must follow the patterns used for the `java.util.regex'package. The default is to exclude no columns, and include all columns. Set `utf8OutsideBmpIncludedColumnNamePattern' to specify exclusion rules to utf8OutsideBmpExcludedColumnNamePattern". The regex must follow the patterns used for the `java.util.regex' package. *Bugs fixed:* * `setObject(int, Object, int, int)' delegate in PreparedStatementWrapper delegates to wrong method. (Bug #30892) * NPE with null column values when `padCharsWithSpace' is set to true. (Bug #30851) * Collation on *Note `VARBINARY': binary-varbinary. column types would be misidentified. A fix has been added, but this fix only works for MySQL server versions 5.0.25 and newer, since earlier versions didn't consistently return correct metadata for functions, and thus results from subqueries and functions were indistinguishable from each other, leading to type-related bugs. (Bug #30664) * An `ArithmeticException' or `NullPointerException' would be raised when the batch had zero members and `rewriteBatchedStatements=true' when `addBatch()' was never called, or `executeBatch()' was called immediately after `clearBatch()'. (Bug #30550) * Closing a load-balanced connection would cause a `ClassCastException'. (Bug #29852) * Connection checker for JBoss didn't use same method parameters using reflection, causing connections to always seem "bad". (Bug #29106) * `DatabaseMetaData.getTypeInfo()' for the types *Note `DECIMAL': numeric-types. and *Note `NUMERIC': numeric-types. will return a precision of 254 for server versions older than 5.0.3, 64 for versions 5.0.3 to 5.0.5 and 65 for versions newer than 5.0.5. (Bug #28972) * `CallableStatement.executeBatch()' doesn't work when connection property `noAccessToProcedureBodies' has been set to `true'. The fix involves changing the behavior of `noAccessToProcedureBodies',in that the driver will now report all paramters as `IN' paramters but permit callers to call registerOutParameter() on them without throwing an exception. (Bug #28689) * `DatabaseMetaData.getColumns()' doesn't contain `SCOPE_*' or `IS_AUTOINCREMENT' columns. (Bug #27915) * Schema objects with identifiers other than the connection character aren't retrieved correctly in `ResultSetMetadata'. (Bug #27867) * `Connection.getServerCharacterEncoding()' doesn't work for servers with version >= 4.1. (Bug #27182) * The automated SVN revisions in `DBMD.getDriverVersion()'. The SVN revision of the directory is now inserted into the version information during the build. (Bug #21116) * Specifying a "validation query" in your connection pool that starts with "/* ping */" _exactly_ will cause the driver to instead send a ping to the server and return a fake result set (much lighter weight), and when using a ReplicationConnection or a LoadBalancedConnection, will send the ping across all active connections.  File: manual.info, Node: cj-news-5-1-2, Next: cj-news-5-1-1, Prev: cj-news-5-1-3, Up: cj-news-5-1 D.6.1.14 Changes in MySQL Connector/J 5.1.2 (29 June 2007) .......................................................... This is a new Beta development release, fixing recently discovered bugs. *Functionality added or changed:* * Setting the configuration property `rewriteBatchedStatements' to `true' will now cause the driver to rewrite batched prepared statements with more than 3 parameter sets in a batch into multi-statements (separated by ";") if they are not plain (that is, without *Note `SELECT': select. or `ON DUPLICATE KEY UPDATE' clauses) *Note `INSERT': insert. or *Note `REPLACE': replace. statements.  File: manual.info, Node: cj-news-5-1-1, Next: cj-news-5-1-0, Prev: cj-news-5-1-2, Up: cj-news-5-1 D.6.1.15 Changes in MySQL Connector/J 5.1.1 (22 June 2007) .......................................................... This is a new Alpha development release, adding new features and fixing recently discovered bugs. *Functionality added or changed:* * *Incompatible Change*: Pulled vendor-extension methods of `Connection' implementation out into an interface to support `java.sql.Wrapper' functionality from `ConnectionPoolDataSource'. The vendor extensions are javadoc'd in the `com.mysql.jdbc.Connection' interface. For those looking further into the driver implementation, it is not an API that is used for plugability of implementations inside our driver (which is why there are still references to `ConnectionImpl' throughout the code). We've also added server and client `prepareStatement()' methods that cover all of the variants in the JDBC API. `Connection.serverPrepare(String)' has been re-named to `Connection.serverPrepareStatement()' for consistency with `Connection.clientPrepareStatement()'. * Row navigation now causes any streams/readers open on the result set to be closed, as in some cases we're reading directly from a shared network packet and it will be overwritten by the "next" row. * Made it possible to retrieve prepared statement parameter bindings (to be used in `StatementInterceptors', primarily). * Externalized the descriptions of connection properties. * The data (and how it is stored) for `ResultSet' rows are now behind an interface which enables us (in some cases) to allocate less memory per row, in that for "streaming" result sets, we re-use the packet used to read rows, since only one row at a time is ever active. * Similar to `Connection', we pulled out vendor extensions to `Statement' into an interface named `com.mysql.Statement', and moved the `Statement' class into `com.mysql.StatementImpl'. The two methods (javadoc'd in `com.mysql.Statement' are `enableStreamingResults()', which already existed, and `disableStreamingResults()' which sets the statement instance back to the fetch size and result set type it had before `enableStreamingResults()' was called. * Driver now picks appropriate internal row representation (whole row in one buffer, or individual byte[]s for each column value) depending on heuristics, including whether or not the row has *Note `BLOB': blob. or *Note `TEXT': blob. types and the overall row-size. The threshold for row size that will cause the driver to use a buffer rather than individual byte[]s is configured by the configuration property `largeRowSizeThreshold', which has a default value of 2KB. * Added experimental support for statement "interceptors" through the `com.mysql.jdbc.StatementInterceptor' interface, examples are in `com/mysql/jdbc/interceptors'. Implement this interface to be placed "in between" query execution, so that you can influence it. (currently experimental). `StatementInterceptors' are "chainable" when configured by the user, the results returned by the "current" interceptor will be passed on to the next on in the chain, from left-to-right order, as specified by the user in the JDBC configuration property `statementInterceptors'. * See the sources (fully javadoc'd) for `com.mysql.jdbc.StatementInterceptor' for more details until we iron out the API and get it documented in the manual. * Setting `rewriteBatchedStatements' to `true' now causes `CallableStatements' with batched arguments to be re-written in the form `CALL (...); CALL (...); ...' to send the batch in as few client/server round trips as possible.  File: manual.info, Node: cj-news-5-1-0, Prev: cj-news-5-1-1, Up: cj-news-5-1 D.6.1.16 Changes in MySQL Connector/J 5.1.0 (11 April 2007) ........................................................... This is the first public alpha release of the current Connector/J 5.1 development branch, providing an insight to upcoming features. Although some of these are still under development, this release includes the following new features and changes (in comparison to the current Connector/J 5.0 production release): *Important change:* Due to a number of issues with the use of server-side prepared statements, Connector/J 5.0.5 has disabled their use by default. The disabling of server-side prepared statements does not affect the operation of the connector in any way. To enable server-side prepared statements you must add the following configuration property to your connector string: useServerPrepStmts=true The default value of this property is `false' (that is, Connector/J does not use server-side prepared statements). *Note*: The disabling of server-side prepared statements does not affect the operation of the connector. However, if you use the `useTimezone=true' connection option and use client-side prepared statements (instead of server-side prepared statements) you should also set `useSSPSCompatibleTimezoneShift=true'. *Functionality added or changed:* * Refactored `CommunicationsException' into a JDBC-3.0 version, and a JDBC-4.0 version (which extends `SQLRecoverableException', now that it exists). *Note*: This change means that if you were catching `com.mysql.jdbc.CommunicationsException' in your applications instead of looking at the SQLState class of `08', and are moving to Java 6 (or newer), you need to change your imports to that exception to be `com.mysql.jdbc.exceptions.jdbc4.CommunicationsException', as the old class will not be instantiated for communications link-related errors under Java 6. * Added support for JDBC-4.0 categorized `SQLExceptions'. * Added support for JDBC-4.0's `NCLOB', and *Note `NCHAR': char./*Note `NVARCHAR': char. types. * `com.mysql.jdbc.java6.javac': Full path to your Java-6 `javac' executable * Added support for JDBC-4.0's SQLXML interfaces. * Re-worked Ant buildfile to build JDBC-4.0 classes separately, as well as support building under Eclipse (since Eclipse can't mix/match JDKs). To build, you must set `JAVA_HOME' to J2SDK-1.4.2 or Java-5, and set the following properties on your Ant command line: * `com.mysql.jdbc.java6.javac': Full path to your Java-6 `javac' executable * `com.mysql.jdbc.java6.rtjar': Full path to your Java-6 `rt.jar' file * New feature--driver will automatically adjust session variable `net_write_timeout' when it determines it has been asked for a "streaming" result, and resets it to the previous value when the result set has been consumed. (configuration property is named `netTimeoutForStreamingResults' value and has a unit of seconds, the value `0' means the driver will not try and adjust this value). * Added support for JDBC-4.0's client information. The backend storage of information provided using `Connection.setClientInfo()' and retrieved by `Connection.getClientInfo()' is pluggable by any class that implements the `com.mysql.jdbc.JDBC4ClientInfoProvider' interface and has a no-args constructor. The implementation used by the driver is configured using the `clientInfoProvider' configuration property (with a default of value of `com.mysql.jdbc.JDBC4CommentClientInfoProvider', an implementation which lists the client information as a comment prepended to every query sent to the server). This functionality is only available when using Java-6 or newer. * `com.mysql.jdbc.java6.rtjar': Full path to your Java-6 `rt.jar' file * Added support for JDBC-4.0's `Wrapper' interface.  File: manual.info, Node: cj-news-5-0, Next: cg-news-3-1, Prev: cj-news-5-1, Up: cj-news D.6.2 Changes in MySQL Connector/J 5.0.x ---------------------------------------- * Menu: * cj-news-5-0-8:: Changes in MySQL Connector/J 5.0.8 (09 October 2007) * cj-news-5-0-7:: Changes in MySQL Connector/J 5.0.7 (20 July 2007) * cj-news-5-0-6:: Changes in MySQL Connector/J 5.0.6 (15 May 2007) * cj-news-5-0-5:: Changes in MySQL Connector/J 5.0.5 (02 March 2007) * cj-news-5-0-4:: Changes in MySQL Connector/J 5.0.4 (20 October 2006) * cj-news-5-0-3:: Changes in MySQL Connector/J 5.0.3 (26 July 2006 beta) * cj-news-5-0-2:: Changes in MySQL Connector/J 5.0.2 (11 July 2006) * cj-news-5-0-1:: Changes in MySQL Connector/J 5.0.1 (Not Released) * cj-news-5-0-0:: Changes in MySQL Connector/J 5.0.0 (22 December 2005)  File: manual.info, Node: cj-news-5-0-8, Next: cj-news-5-0-7, Prev: cj-news-5-0, Up: cj-news-5-0 D.6.2.1 Changes in MySQL Connector/J 5.0.8 (09 October 2007) ............................................................ *Functionality added or changed:* * `blobsAreStrings': Should the driver always treat BLOBs as Strings. Added specifically to work around dubious metadata returned by the server for `GROUP BY' clauses. Defaults to false. * Added two configuration parameters: * `blobsAreStrings': Should the driver always treat BLOBs as Strings. Added specifically to work around dubious metadata returned by the server for `GROUP BY' clauses. Defaults to false. * `functionsNeverReturnBlobs': Should the driver always treat data from functions returning `BLOBs' as Strings. Added specifically to work around dubious metadata returned by the server for `GROUP BY' clauses. Defaults to false. * `functionsNeverReturnBlobs': Should the driver always treat data from functions returning `BLOBs' as Strings. Added specifically to work around dubious metadata returned by the server for `GROUP BY' clauses. Defaults to false. * XAConnections now start in auto-commit mode (as per JDBC-4.0 specification clarification). * Driver will now fall back to sane defaults for `max_allowed_packet' and `net_buffer_length' if the server reports them incorrectly (and will log this situation at `WARN' level, since it is actually an error condition). *Bugs fixed:* * Connections established using URLs of the form `jdbc:mysql:loadbalance://' weren't doing failover if they tried to connect to a MySQL server that was down. The driver now attempts connections to the next "best" (depending on the load balance strategy in use) server, and continues to attempt connecting to the next "best" server every 250 milliseconds until one is found that is up and running or 5 minutes has passed. If the driver gives up, it will throw the last-received `SQLException'. (Bug #31053) * `setObject(int, Object, int, int)' delegate in PreparedStatementWrapper delegates to wrong method. (Bug #30892) * NPE with null column values when `padCharsWithSpace' is set to true. (Bug #30851) * Collation on *Note `VARBINARY': binary-varbinary. column types would be misidentified. A fix has been added, but this fix only works for MySQL server versions 5.0.25 and newer, since earlier versions didn't consistently return correct metadata for functions, and thus results from subqueries and functions were indistinguishable from each other, leading to type-related bugs. (Bug #30664) * An `ArithmeticException' or `NullPointerException' would be raised when the batch had zero members and `rewriteBatchedStatements=true' when `addBatch()' was never called, or `executeBatch()' was called immediately after `clearBatch()'. (Bug #30550) * Closing a load-balanced connection would cause a `ClassCastException'. (Bug #29852) * Connection checker for JBoss didn't use same method parameters using reflection, causing connections to always seem "bad". (Bug #29106) * `DatabaseMetaData.getTypeInfo()' for the types *Note `DECIMAL': numeric-types. and *Note `NUMERIC': numeric-types. will return a precision of 254 for server versions older than 5.0.3, 64 for versions 5.0.3 to 5.0.5 and 65 for versions newer than 5.0.5. (Bug #28972) * `CallableStatement.executeBatch()' doesn't work when connection property `noAccessToProcedureBodies' has been set to `true'. The fix involves changing the behavior of `noAccessToProcedureBodies',in that the driver will now report all paramters as `IN' paramters but permit callers to call registerOutParameter() on them without throwing an exception. (Bug #28689) * When a connection is in read-only mode, queries that are wrapped in parentheses were incorrectly identified DML statements. (Bug #28256) * `UNSIGNED' types not reported using `DBMD.getTypeInfo()', and capitalization of type names is not consistent between `DBMD.getColumns()', `RSMD.getColumnTypeName()' and `DBMD.getTypeInfo()'. This fix also ensures that the precision of `UNSIGNED MEDIUMINT' and `UNSIGNED BIGINT' is reported correctly using `DBMD.getColumns()'. (Bug #27916) * `DatabaseMetaData.getColumns()' doesn't contain `SCOPE_*' or `IS_AUTOINCREMENT' columns. (Bug #27915) * Schema objects with identifiers other than the connection character aren't retrieved correctly in `ResultSetMetadata'. (Bug #27867) * Cached metadata with `PreparedStatement.execute()' throws `NullPointerException'. (Bug #27412) * `Connection.getServerCharacterEncoding()' doesn't work for servers with version >= 4.1. (Bug #27182) * The automated SVN revisions in `DBMD.getDriverVersion()'. The SVN revision of the directory is now inserted into the version information during the build. (Bug #21116) * Specifying a "validation query" in your connection pool that starts with "/* ping */" _exactly_ will cause the driver to instead send a ping to the server and return a fake result set (much lighter weight), and when using a ReplicationConnection or a LoadBalancedConnection, will send the ping across all active connections.  File: manual.info, Node: cj-news-5-0-7, Next: cj-news-5-0-6, Prev: cj-news-5-0-8, Up: cj-news-5-0 D.6.2.2 Changes in MySQL Connector/J 5.0.7 (20 July 2007) ......................................................... *Functionality added or changed:* * The driver will now automatically set `useServerPrepStmts' to `true' when `useCursorFetch' has been set to `true', since the feature requires server-side prepared statements to function. * `tcpKeepAlive' - Should the driver set SO_KEEPALIVE (default `true')? * Give more information in EOFExceptions thrown out of MysqlIO (how many bytes the driver expected to read, how many it actually read, say that communications with the server were unexpectedly lost). * Driver detects when it is running in a ColdFusion MX server (tested with version 7), and uses the configuration bundle `coldFusion', which sets `useDynamicCharsetInfo' to `false' (see previous entry), and sets `useLocalSessionState' and autoReconnect to `true'. * `tcpNoDelay' - Should the driver set SO_TCP_NODELAY (disabling the Nagle Algorithm, default `true')? * Added configuration property `slowQueryThresholdNanos' - if `useNanosForElapsedTime' is set to `true', and this property is set to a nonzero value the driver will use this threshold (in nanosecond units) to determine if a query was slow, instead of using millisecond units. * `tcpRcvBuf' - Should the driver set SO_RCV_BUF to the given value? The default value of '0', means use the platform default value for this property. * Setting `useDynamicCharsetInfo' to `false' now causes driver to use static lookups for collations as well (makes ResultSetMetadata.isCaseSensitive() much more efficient, which leads to performance increase for ColdFusion, which calls this method for every column on every table it sees, it appears). * Added configuration properties to enable tuning of TCP/IP socket parameters: * `tcpNoDelay' - Should the driver set SO_TCP_NODELAY (disabling the Nagle Algorithm, default `true')? * `tcpKeepAlive' - Should the driver set SO_KEEPALIVE (default `true')? * `tcpRcvBuf' - Should the driver set SO_RCV_BUF to the given value? The default value of '0', means use the platform default value for this property. * `tcpSndBuf' - Should the driver set SO_SND_BUF to the given value? The default value of '0', means use the platform default value for this property. * `tcpTrafficClass' - Should the driver set traffic class or type-of-service fields? See the documentation for java.net.Socket.setTrafficClass() for more information. * Setting the configuration parameter `useCursorFetch' to `true' for MySQL-5.0+ enables the use of cursors that enable Connector/J to save memory by fetching result set rows in chunks (where the chunk size is set by calling setFetchSize() on a Statement or ResultSet) by using fully-materialized cursors on the server. * `tcpSndBuf' - Should the driver set SO_SND_BUF to the given value? The default value of '0', means use the platform default value for this property. * `tcpTrafficClass' - Should the driver set traffic class or type-of-service fields? See the documentation for java.net.Socket.setTrafficClass() for more information. * Added new debugging functionality - Setting configuration property `includeInnodbStatusInDeadlockExceptions' to `true' will cause the driver to append the output of *Note `SHOW ENGINE INNODB STATUS': show-engine. to deadlock-related exceptions, which will enumerate the current locks held inside InnoDB. * Added configuration property `useNanosForElapsedTime' - for profiling/debugging functionality that measures elapsed time, should the driver try to use nanoseconds resolution if available (requires JDK >= 1.5)? *Note*: If `useNanosForElapsedTime' is set to `true', and this property is set to "0" (or left default), then elapsed times will still be measured in nanoseconds (if possible), but the slow query threshold will be converted from milliseconds to nanoseconds, and thus have an upper bound of approximately 2000 milliseconds (as that threshold is represented as an integer, not a long). *Bugs fixed:* * Don't send any file data in response to LOAD DATA LOCAL INFILE if the feature is disabled at the client side. This is to prevent a malicious server or man-in-the-middle from asking the client for data that the client is not expecting. Thanks to Jan Kneschke for discovering the exploit and Andrey "Poohie" Hristov, Konstantin Osipov and Sergei Golubchik for discussions about implications and possible fixes. (Bug #29605) * Parser in client-side prepared statements runs to end of statement, rather than end-of-line for '#' comments. Also added support for '-' single-line comments. (Bug #28956) * Parser in client-side prepared statements eats character following '/' if it is not a multi-line comment. (Bug #28851) * PreparedStatement.getMetaData() for statements containing leading one-line comments is not returned correctly. As part of this fix, we also overhauled detection of DML for `executeQuery()' and *Note `SELECT': select.s for `executeUpdate()' in plain and prepared statements to be aware of the same types of comments. (Bug #28469)  File: manual.info, Node: cj-news-5-0-6, Next: cj-news-5-0-5, Prev: cj-news-5-0-7, Up: cj-news-5-0 D.6.2.3 Changes in MySQL Connector/J 5.0.6 (15 May 2007) ........................................................ *Functionality added or changed:* * Added an experimental load-balanced connection designed for use with SQL nodes in a MySQL Cluster/NDB environment (This is not for master-slave replication. For that, we suggest you look at `ReplicationConnection' or `lbpool'). If the JDBC URL starts with `jdbc:mysql:loadbalance://host-1,host-2,...host-n', the driver will create an implementation of `java.sql.Connection' that load balances requests across a series of MySQL JDBC connections to the given hosts, where the balancing takes place after transaction commit. Therefore, for this to work (at all), you must use transactions, even if only reading data. Physical connections to the given hosts will not be created until needed. The driver will invalidate connections that it detects have had communication errors when processing a request. A new connection to the problematic host will be attempted the next time it is selected by the load balancing algorithm. There are two choices for load balancing algorithms, which may be specified by the `loadBalanceStrategy' JDBC URL configuration property: * `random': The driver will pick a random host for each request. This tends to work better than round-robin, as the randomness will somewhat account for spreading loads where requests vary in response time, while round-robin can sometimes lead to overloaded nodes if there are variations in response times across the workload. * `bestResponseTime': The driver will route the request to the host that had the best response time for the previous transaction. * `bestResponseTime': The driver will route the request to the host that had the best response time for the previous transaction. * Added configuration property `padCharsWithSpace' (defaults to `false'). If set to `true', and a result set column has the *Note `CHAR': char. type and the value does not fill the amount of characters specified in the DDL for the column, the driver will pad the remaining characters with space (for ANSI compliance). * When `useLocalSessionState' is set to `true' and connected to a MySQL-5.0 or later server, the JDBC driver will now determine whether an actual `commit' or `rollback' statement needs to be sent to the database when `Connection.commit()' or `Connection.rollback()' is called. This is especially helpful for high-load situations with connection pools that always call `Connection.rollback()' on connection check-in/check-out because it avoids a round-trip to the server. * Added configuration property `useDynamicCharsetInfo'. If set to `false' (the default), the driver will use a per-connection cache of character set information queried from the server when necessary, or when set to `true', use a built-in static mapping that is more efficient, but isn't aware of custom character sets or character sets implemented after the release of the JDBC driver. *Note*: This only affects the `padCharsWithSpace' configuration property and the `ResultSetMetaData.getColumnDisplayWidth()' method. * New configuration property, `enableQueryTimeouts' (default `true'). When enabled, query timeouts set with `Statement.setQueryTimeout()' use a shared `java.util.Timer' instance for scheduling. Even if the timeout doesn't expire before the query is processed, there will be memory used by the `TimerTask' for the given timeout which won't be reclaimed until the time the timeout would have expired if it hadn't been cancelled by the driver. High-load environments might want to consider disabling this functionality. (this configuration property is part of the `maxPerformance' configuration bundle). * Give better error message when "streaming" result sets, and the connection gets clobbered because of exceeding `net_write_timeout' on the server. * `random': The driver will pick a random host for each request. This tends to work better than round-robin, as the randomness will somewhat account for spreading loads where requests vary in response time, while round-robin can sometimes lead to overloaded nodes if there are variations in response times across the workload. * `com.mysql.jdbc.[NonRegistering]Driver' now understands URLs of the format `jdbc:mysql:replication://' and `jdbc:mysql:loadbalance://' which will create a ReplicationConnection (exactly like when using `[NonRegistering]ReplicationDriver') and an experimental load-balanced connection designed for use with SQL nodes in a MySQL Cluster/NDB environment, respectively. In an effort to simplify things, we're working on deprecating multiple drivers, and instead specifying different core behavior based upon JDBC URL prefixes, so watch for `[NonRegistering]ReplicationDriver' to eventually disappear, to be replaced with `com.mysql.jdbc[NonRegistering]Driver' with the new URL prefix. * Fixed issue where a failed-over connection would let an application call `setReadOnly(false)', when that call should be ignored until the connection is reconnected to a writable master unless `failoverReadOnly' had been set to `false'. * Driver will now use `INSERT INTO ... VALUES (DEFAULT)'form of statement for updatable result sets for `ResultSet.insertRow()', rather than pre-populating the insert row with values from `DatabaseMetaData.getColumns()'(which results in a *Note `SHOW FULL COLUMNS': show-columns. on the server for every result set). If an application requires access to the default values before `insertRow()' has been called, the JDBC URL should be configured with `populateInsertRowWithDefaultValues' set to `true'. This fix specifically targets performance issues with ColdFusion and the fact that it seems to ask for updatable result sets no matter what the application does with them. * More intelligent initial packet sizes for the "shared" packets are used (512 bytes, rather than 16K), and initial packets used during handshake are now sized appropriately as to not require reallocation. *Bugs fixed:* * More useful error messages are generated when the driver thinks a result set is not updatable. (Thanks to Ashley Martens for the patch). (Bug #28085) * `Connection.getTransactionIsolation()' uses "`SHOW VARIABLES LIKE'" which is very inefficient on MySQL-5.0+ servers. (Bug #27655) * Fixed issue where calling `getGeneratedKeys()' on a prepared statement after calling `execute()' didn't always return the generated keys (`executeUpdate()' worked fine however). (Bug #27655) * `CALL /* ... */ SOME_PROC()' doesn't work. As a side effect of this fix, you can now use `/* */' and `#' comments when preparing statements using client-side prepared statement emulation. If the comments happen to contain parameter markers (`?'), they will be treated as belonging to the comment (that is, not recognized) rather than being a parameter of the statement. *Note*: The statement when sent to the server will contain the comments as-is, they're not stripped during the process of preparing the `PreparedStatement' or `CallableStatement'. (Bug #27400) * `ResultSet.get*()' with a column index < 1 returns misleading error message. (Bug #27317) * Using `ResultSet.get*()' with a column index less than 1 returns a misleading error message. (Bug #27317) * Comments in DDL of stored procedures/functions confuse procedure parser, and thus metadata about them can not be created, leading to inability to retrieve said metadata, or execute procedures that have certain comments in them. (Bug #26959) * Fast date/time parsing doesn't take into account `00:00:00' as a legal value. (Bug #26789) * `PreparedStatement' is not closed in `BlobFromLocator.getBytes()'. (Bug #26592) * When the configuration property `useCursorFetch' was set to `true', sometimes server would return new, more exact metadata during the execution of the server-side prepared statement that enables this functionality, which the driver ignored (using the original metadata returned during `prepare()'), causing corrupt reading of data due to type mismatch when the actual rows were returned. (Bug #26173) * `CallableStatements' with `OUT/INOUT' parameters that are "binary" (*Note `BLOB': blob, *Note `BIT': numeric-types, `(VAR)BINARY', `JAVA_OBJECT') have extra 7 bytes. (Bug #25715) * Whitespace surrounding storage/size specifiers in stored procedure parameters declaration causes `NumberFormatException' to be thrown when calling stored procedure on JDK-1.5 or newer, as the Number classes in JDK-1.5+ are whitespace intolerant. (Bug #25624) * Client options not sent correctly when using SSL, leading to stored procedures not being able to return results. Thanks to Don Cohen for the bug report, testcase and patch. (Bug #25545) * `Statement.setMaxRows()' is not effective on result sets materialized from cursors. (Bug #25517) * `BIT(> 1)' is returned as `java.lang.String' from `ResultSet.getObject()' rather than `byte[]'. (Bug #25328)  File: manual.info, Node: cj-news-5-0-5, Next: cj-news-5-0-4, Prev: cj-news-5-0-6, Up: cj-news-5-0 D.6.2.4 Changes in MySQL Connector/J 5.0.5 (02 March 2007) .......................................................... *Functionality added or changed:* * Usage Advisor will now issue warnings for result sets with large numbers of rows. You can configure the trigger value by using the `resultSetSizeThreshold' parameter, which has a default value of 100. * The `rewriteBatchedStatements' feature can now be used with server-side prepared statements. * *Important change:* Due to a number of issues with the use of server-side prepared statements, Connector/J 5.0.5 has disabled their use by default. The disabling of server-side prepared statements does not affect the operation of the connector in any way. To enable server-side prepared statements you must add the following configuration property to your connector string: useServerPrepStmts=true The default value of this property is `false' (that is, Connector/J does not use server-side prepared statements). * Improved speed of `datetime' parsing for ResultSets that come from plain or nonserver-side prepared statements. You can enable old implementation with `useFastDateParsing=false' as a configuration parameter. * Usage Advisor now detects empty results sets and does not report on columns not referenced in those empty sets. * Fixed logging of XA commands sent to server, it is now configurable using `logXaCommands' property (defaults to `false'). * Added configuration property `localSocketAddress', which is the host name or IP address given to explicitly configure the interface that the driver will bind the client side of the TCP/IP connection to when connecting. * We've added a new configuration option `treatUtilDateAsTimestamp', which is `false' by default, as (1) We already had specific behavior to treat java.util.Date as a java.sql.Timestamp because it is useful to many folks, and (2) that behavior will very likely be required for drivers JDBC-post-4.0. *Bugs fixed:* * Connection property `socketFactory' wasn't exposed using correctly named mutator/accessor, causing data source implementations that use JavaBean naming conventions to set properties to fail to set the property (and in the case of SJAS, fail silently when trying to set this parameter). (Bug #26326) * A query execution which timed out did not always throw a `MySQLTimeoutException'. (Bug #25836) * Storing a `java.util.Date' object in a *Note `BLOB': blob. column would not be serialized correctly during `setObject'. (Bug #25787) * Timer instance used for `Statement.setQueryTimeout()' created per-connection, rather than per-VM, causing memory leak. (Bug #25514) * `EscapeProcessor' gets confused by multiple backslashes. We now push the responsibility of syntax errors back on to the server for most escape sequences. (Bug #25399) * `INOUT' parameters in `CallableStatements' get doubly-escaped. (Bug #25379) * When using the `rewriteBatchedStatements' connection option with `PreparedState.executeBatch()' an internal memory leak would occur. (Bug #25073) * Fixed issue where field-level for metadata from `DatabaseMetaData' when using `INFORMATION_SCHEMA' didn't have references to current connections, sometimes leading to Null Pointer Exceptions (NPEs) when introspecting them using `ResultSetMetaData'. (Bug #25073) * `StringUtils.indexOfIgnoreCaseRespectQuotes()' isn't case-insensitive on the first character of the target. This bug also affected `rewriteBatchedStatements' functionality when prepared statements did not use uppercase for the `VALUES' clause. (Bug #25047) * Client-side prepared statement parser gets confused by in-line comments `/*...*/' and therefore cannot rewrite batch statements or reliably detect the type of statements when they are used. (Bug #25025) * Results sets from *Note `UPDATE': update. statements that are part of multi-statement queries would cause an `SQLException' error, "Result is from UPDATE". (Bug #25009) * Specifying `US-ASCII' as the character set in a connection to a MySQL 4.1 or newer server does not map correctly. (Bug #24840) * Using `DatabaseMetaData.getSQLKeywords()' does not return a all of the of the reserved keywords for the current MySQL version. Current implementation returns the list of reserved words for MySQL 5.1, and does not distinguish between versions. (Bug #24794) * Calling `Statement.cancel()' could result in a Null Pointer Exception (NPE). (Bug #24721) * Using `setFetchSize()' breaks prepared *Note `SHOW': show. and other commands. (Bug #24360) * Calendars and timezones are now lazily instantiated when required. (Bug #24351) * Using *Note `DATETIME': datetime. columns would result in time shifts when `useServerPrepStmts' was true. This occurred due to different behavior when using client-side compared to server-side prepared statements and the `useJDBCCompliantTimezoneShift' option. This is now fixed if moving from server-side prepared statements to client-side prepared statements by setting `useSSPSCompatibleTimezoneShift' to `true', as the driver can't tell if this is a new deployment that never used server-side prepared statements, or if it is an existing deployment that is switching to client-side prepared statements from server-side prepared statements. (Bug #24344) * Connector/J now returns a better error message when server doesn't return enough information to determine stored procedure/function parameter types. (Bug #24065) * A connection error would occur when connecting to a MySQL server with certain character sets. Some collations/character sets reported as "unknown" (specifically `cias' variants of existing character sets), and inability to override the detected server character set. (Bug #23645) * Inconsistency between `getSchemas' and `INFORMATION_SCHEMA'. (Bug #23304) * `DatabaseMetaData.getSchemas()' doesn't return a `TABLE_CATALOG' column. (Bug #23303) * When using a JDBC connection URL that is malformed, the `NonRegisteringDriver.getPropertyInfo' method will throw a Null Pointer Exception (NPE). (Bug #22628) * Some exceptions thrown out of `StandardSocketFactory' were needlessly wrapped, obscuring their true cause, especially when using socket timeouts. (Bug #21480) * When using a server-side prepared statement the driver would send timestamps to the server using nanoseconds instead of milliseconds. (Bug #21438) * When using server-side prepared statements and timestamp columns, value would be incorrectly populated (with nanoseconds, not microseconds). (Bug #21438) * `ParameterMetaData' throws `NullPointerException' when prepared SQL has a syntax error. Added `generateSimpleParameterMetadata' configuration property, which when set to `true' will generate metadata reflecting *Note `VARCHAR': char. for every parameter (the default is `false', which will cause an exception to be thrown if no parameter metadata for the statement is actually available). (Bug #21267) * Fixed an issue where `XADataSources' couldn't be bound into JNDI, as the `DataSourceFactory' didn't know how to create instances of them. *Other changes:* * Avoid static synchronized code in JVM class libraries for dealing with default timezones. * Performance enhancement of initial character set configuration, driver will only send commands required to configure connection character set session variables if the current values on the server do not match what is required. * Re-worked stored procedure parameter parser to be more robust. Driver no longer requires `BEGIN' in stored procedure definition, but does have requirement that if a stored function begins with a label directly after the "returns" clause, that the label is not a quoted identifier. * Throw exceptions encountered during timeout to thread calling `Statement.execute*()', rather than `RuntimeException'. * Changed cached result set metadata (when using `cacheResultSetMetadata=true') to be cached per-connection rather than per-statement as previously implemented. * Reverted back to internal character conversion routines for single-byte character sets, as the ones internal to the JVM are using much more CPU time than our internal implementation. * When extracting foreign key information from *Note `SHOW CREATE TABLE': show-create-table. in `DatabaseMetaData', ignore exceptions relating to tables being missing (which could happen for cross-reference or imported-key requests, as the list of tables is generated first, then iterated). * Fixed some Null Pointer Exceptions (NPEs) when cached metadata was used with `UpdatableResultSets'. * Take `localSocketAddress' property into account when creating instances of `CommunicationsException' when the underlying exception is a `java.net.BindException', so that a friendlier error message is given with a little internal diagnostics. * Fixed cases where `ServerPreparedStatements' weren't using cached metadata when `cacheResultSetMetadata=true' was used. * Use a `java.util.TreeMap' to map column names to ordinal indexes for `ResultSet.findColumn()' instead of a HashMap. This enables us to have case-insensitive lookups (required by the JDBC specification) without resorting to the many transient object instances needed to support this requirement with a normal `HashMap' with either case-adjusted keys, or case-insensitive keys. (In the worst case scenario for lookups of a 1000 column result set, TreeMaps are about half as fast wall-clock time as a HashMap, however in normal applications their use gives many orders of magnitude reduction in transient object instance creation which pays off later for CPU usage in garbage collection). * When using cached metadata, skip field-level metadata packets coming from the server, rather than reading them and discarding them without creating `com.mysql.jdbc.Field' instances.  File: manual.info, Node: cj-news-5-0-4, Next: cj-news-5-0-3, Prev: cj-news-5-0-5, Up: cj-news-5-0 D.6.2.5 Changes in MySQL Connector/J 5.0.4 (20 October 2006) ............................................................ *Bugs fixed:* * DBMD.getColumns() does not return expected COLUMN_SIZE for the SET type, now returns length of largest possible set disregarding whitespace or the "," delimitters to be consistent with the ODBC driver. (Bug #22613) * Added new _ci collations to CharsetMapping - utf8_unicode_ci not working. (Bug #22456) * Driver was using milliseconds for Statement.setQueryTimeout() when specification says argument is to be in seconds. (Bug #22359) * Workaround for server crash when calling stored procedures using a server-side prepared statement (driver now detects prepare(stored procedure) and substitutes client-side prepared statement). (Bug #22297) * Driver issues truncation on write exception when it shouldn't (due to sending big decimal incorrectly to server with server-side prepared statement). (Bug #22290) * Newlines causing whitespace to span confuse procedure parser when getting parameter metadata for stored procedures. (Bug #22024) * When using information_schema for metadata, COLUMN_SIZE for getColumns() is not clamped to range of java.lang.Integer as is the case when not using information_schema, thus leading to a truncation exception that isn't present when not using information_schema. (Bug #21544) * Column names don't match metadata in cases where server doesn't return original column names (column functions) thus breaking compatibility with applications that expect 1-to-1 mappings between `findColumn()' and `rsmd.getColumnName()', usually manifests itself as "Can't find column (")" exceptions. (Bug #21379) * Driver now sends numeric 1 or 0 for client-prepared statement `setBoolean()' calls instead of '1' or '0'. * Fixed configuration property `jdbcCompliantTruncation' was not being used for reads of result set values. * DatabaseMetaData correctly reports `true' for `supportsCatalog*()' methods. * Driver now supports `{call sp}' (without "()" if procedure has no arguments).  File: manual.info, Node: cj-news-5-0-3, Next: cj-news-5-0-2, Prev: cj-news-5-0-4, Up: cj-news-5-0 D.6.2.6 Changes in MySQL Connector/J 5.0.3 (26 July 2006 beta) .............................................................. *Functionality added or changed:* * Added configuration option `noAccessToProcedureBodies' which will cause the driver to create basic parameter metadata for `CallableStatements' when the user does not have access to procedure bodies using *Note `SHOW CREATE PROCEDURE': show-create-procedure. or selecting from `mysql.proc' instead of throwing an exception. The default value for this option is `false' *Bugs fixed:* * Fixed `Statement.cancel()' causes `NullPointerException' if underlying connection has been closed due to server failure. (Bug #20650) * If the connection to the server has been closed due to a server failure, then the cleanup process will call ` Statement.cancel()', triggering a `NullPointerException', even though there is no active connection. (Bug #20650)  File: manual.info, Node: cj-news-5-0-2, Next: cj-news-5-0-1, Prev: cj-news-5-0-3, Up: cj-news-5-0 D.6.2.7 Changes in MySQL Connector/J 5.0.2 (11 July 2006) ......................................................... *Bugs fixed:* * `MysqlXaConnection.recover(int flags)' now permits combinations of `XAResource.TMSTARTRSCAN' and `TMENDRSCAN'. To simulate the `scanning' nature of the interface, we return all prepared XIDs for `TMSTARTRSCAN', and no new XIDs for calls with `TMNOFLAGS', or `TMENDRSCAN' when not in combination with `TMSTARTRSCAN'. This change was made for API compliance, as well as integration with IBM WebSphere's transaction manager. (Bug #20242) * Fixed `MysqlValidConnectionChecker' for JBoss doesn't work with `MySQLXADataSources'. (Bug #20242) * Added connection/datasource property `pinGlobalTxToPhysicalConnection' (defaults to `false'). When set to `true', when using `XAConnections', the driver ensures that operations on a given XID are always routed to the same physical connection. This enables the `XAConnection' to support `XA START ... JOIN' after *Note `XA END': xa-statements. has been called, and is also a workaround for transaction managers that don't maintain thread affinity for a global transaction (most either always maintain thread affinity, or have it as a configuration option). (Bug #20242) * Better caching of character set converters (per-connection) to remove a bottleneck for multibyte character sets. (Bug #20242) * Fixed `ConnectionProperties' (and thus some subclasses) are not serializable, even though some J2EE containers expect them to be. (Bug #19169) * Fixed driver fails on non-ASCII platforms. The driver was assuming that the platform character set would be a superset of MySQL's `latin1' when doing the handshake for authentication, and when reading error messages. We now use Cp1252 for all strings sent to the server during the handshake phase, and a hard-coded mapping of the `language' system variable to the character set that is used for error messages. (Bug #18086) * Fixed can't use `XAConnection' for local transactions when no global transaction is in progress. (Bug #17401)  File: manual.info, Node: cj-news-5-0-1, Next: cj-news-5-0-0, Prev: cj-news-5-0-2, Up: cj-news-5-0 D.6.2.8 Changes in MySQL Connector/J 5.0.1 (Not Released) ......................................................... Not released due to a packaging error This section has no changelog entries.  File: manual.info, Node: cj-news-5-0-0, Prev: cj-news-5-0-1, Up: cj-news-5-0 D.6.2.9 Changes in MySQL Connector/J 5.0.0 (22 December 2005) ............................................................. *Bugs fixed:* * Added support for Connector/MXJ integration using url subprotocol `jdbc:mysql:mxj://...'. (Bug #14729) * Idle timeouts cause `XAConnections' to whine about rolling themselves back. (Bug #14729) * When fix for Bug#14562 was merged from 3.1.12, added functionality for `CallableStatement''s parameter metadata to return correct information for `.getParameterClassName()'. (Bug #14729) * Added service-provider entry to `META-INF/services/java.sql.Driver' for JDBC-4.0 support. (Bug #14729) * Fuller synchronization of `Connection' to avoid deadlocks when using multithreaded frameworks that multithread a single connection (usually not recommended, but the JDBC spec permits it anyways), part of fix to Bug#14972). (Bug #14729) * Moved all `SQLException' constructor usage to a factory in `SQLError' (ground-work for JDBC-4.0 `SQLState'-based exception classes). (Bug #14729) * Removed Java5-specific calls to `BigDecimal' constructor (when result set value is `''', `(int)0' was being used as an argument indirectly using method return value. This signature doesn't exist prior to Java5.) (Bug #14729) * Implementation of `Statement.cancel()' and `Statement.setQueryTimeout()'. Both require MySQL-5.0.0 or newer server, require a separate connection to issue the *Note `KILL QUERY': kill. statement, and in the case of `setQueryTimeout()' creates an additional thread to handle the timeout functionality. Note: Failures to cancel the statement for `setQueryTimeout()' may manifest themselves as `RuntimeExceptions' rather than failing silently, as there is currently no way to unblock the thread that is executing the query being cancelled due to timeout expiration and have it throw the exception instead. (Bug #14729) * Return "[VAR]BINARY" for `RSMD.getColumnTypeName()' when that is actually the type, and it can be distinguished (MySQL-4.1 and newer). (Bug #14729) * Attempt detection of the MySQL type *Note `BINARY': binary-varbinary. (it is an alias, so this isn't always reliable), and use the `java.sql.Types.BINARY' type mapping for it. * Added unit tests for `XADatasource', as well as friendlier exceptions for XA failures compared to the "stock" `XAException' (which has no messages). * If the connection `useTimezone' is set to `true', then also respect time zone conversions in escape-processed string literals (for example, `"{ts ...}"' and `"{t ...}"'). * Do not permit `.setAutoCommit(true)', or `.commit()' or `.rollback()' on an XA-managed connection as per the JDBC specification. * `XADataSource' implemented (ported from 3.2 branch which won't be released as a product). Use `com.mysql.jdbc.jdbc2.optional.MysqlXADataSource' as your datasource class name in your application server to utilize XA transactions in MySQL-5.0.10 and newer. * Moved `-bin-g.jar' file into separate `debug' subdirectory to avoid confusion. * Return original column name for `RSMD.getColumnName()' if the column was aliased, alias name for `.getColumnLabel()' (if aliased), and original table name for `.getTableName()'. Note this only works for MySQL-4.1 and newer, as older servers don't make this information available to clients. * Setting `useJDBCCompliantTimezoneShift=true' (it is not the default) causes the driver to use GMT for _all_ *Note `TIMESTAMP': datetime./*Note `DATETIME': datetime. time zones, and the current VM time zone for any other type that refers to time zones. This feature can not be used when `useTimezone=true' to convert between server and client time zones. * `PreparedStatement.setString()' didn't work correctly when `sql_mode' on server contained `NO_BACKSLASH_ESCAPES' and no characters that needed escaping were present in the string. * Add one level of indirection of internal representation of `CallableStatement' parameter metadata to avoid class not found issues on JDK-1.3 for `ParameterMetadata' interface (which doesn't exist prior to JDBC-3.0).  File: manual.info, Node: cg-news-3-1, Next: cg-news-3-0, Prev: cj-news-5-0, Up: cj-news D.6.3 Changes in MySQL Connector/J 3.1.x ---------------------------------------- * Menu: * cj-news-3-1-15:: Changes in MySQL Connector/J 3.1.15 (Not yet released) * cj-news-3-1-14:: Changes in MySQL Connector/J 3.1.14 (19 October 2006) * cj-news-3-1-13:: Changes in MySQL Connector/J 3.1.13 (26 May 2006) * cj-news-3-1-12:: Changes in MySQL Connector/J 3.1.12 (30 November 2005) * cj-news-3-1-11:: Changes in MySQL Connector/J 3.1.11 (07 October 2005) * cj-news-3-1-10:: Changes in MySQL Connector/J 3.1.10 (23 June 2005) * cj-news-3-1-9:: Changes in MySQL Connector/J 3.1.9 (22 June 2005) * cj-news-3-1-8:: Changes in MySQL Connector/J 3.1.8 (14 April 2005) * cj-news-3-1-7:: Changes in MySQL Connector/J 3.1.7 (18 February 2005) * cj-news-3-1-6:: Changes in MySQL Connector/J 3.1.6 (23 December 2004) * cj-news-3-1-5:: Changes in MySQL Connector/J 3.1.5 (02 December 2004) * cj-news-3-1-4:: Changes in MySQL Connector/J 3.1.4 (04 September 2004) * cj-news-3-1-3:: Changes in MySQL Connector/J 3.1.3 (07 July 2004) * cj-news-3-1-2:: Changes in MySQL Connector/J 3.1.2 (09 June 2004) * cj-news-3-1-1:: Changes in MySQL Connector/J 3.1.1 (14 February 2004 alpha) * cj-news-3-1-0:: Changes in MySQL Connector/J 3.1.0 (18 February 2003 alpha)  File: manual.info, Node: cj-news-3-1-15, Next: cj-news-3-1-14, Prev: cg-news-3-1, Up: cg-news-3-1 D.6.3.1 Changes in MySQL Connector/J 3.1.15 (Not yet released) .............................................................. *Important change:* Due to a number of issues with the use of server-side prepared statements, Connector/J 5.0.5 has disabled their use by default. The disabling of server-side prepared statements does not affect the operation of the connector in any way. To enable server-side prepared statements you must add the following configuration property to your connector string: useServerPrepStmts=true The default value of this property is `false' (that is, Connector/J does not use server-side prepared statements). *Bugs fixed:* * Specifying `US-ASCII' as the character set in a connection to a MySQL 4.1 or newer server does not map correctly. (Bug #24840)  File: manual.info, Node: cj-news-3-1-14, Next: cj-news-3-1-13, Prev: cj-news-3-1-15, Up: cg-news-3-1 D.6.3.2 Changes in MySQL Connector/J 3.1.14 (19 October 2006) ............................................................. *Bugs fixed:* * Check and store value for continueBatchOnError property in constructor of Statements, rather than when executing batches, so that Connections closed out from underneath statements don't cause NullPointerExceptions when it is required to check this property. (Bug #22290) * Fixed BUG#18258 - DatabaseMetaData.getTables(), columns() with bad catalog parameter threw exception rather than return empty result set (as required by spec). (Bug #22290) * Driver now sends numeric 1 or 0 for client-prepared statement setBoolean() calls instead of '1' or '0'. (Bug #22290) * Fixed bug where driver would not advance to next host if roundRobinLoadBalance=true and the last host in the list is down. (Bug #22290) * Driver issues truncation on write exception when it shouldn't (due to sending big decimal incorrectly to server with server-side prepared statement). (Bug #22290) * Fixed bug when calling stored functions, where parameters weren't numbered correctly (first parameter is now the return value, subsequent parameters if specified start at index "2"). (Bug #22290) * Removed logger autodetection altogether, must now specify logger explicitly if you want to use a logger other than one that logs to STDERR. (Bug #21207) * DDriver throws NPE when tracing prepared statements that have been closed (in asSQL()). (Bug #21207) * ResultSet.getSomeInteger() doesn't work for BIT(>1). (Bug #21062) * Escape of quotation marks in client-side prepared statements parsing not respected. Patch covers more than bug report, including NO_BACKSLASH_ESCAPES being set, and stacked quote characters forms of escaping (that is, " or ""). (Bug #20888) * Fixed can't pool server-side prepared statements, exception raised when re-using them. (Bug #20687) * Fixed Updatable result set that contains a BIT column fails when server-side prepared statements are used. (Bug #20485) * Fixed updatable result set throws ClassCastException when there is row data and moveToInsertRow() is called. (Bug #20479) * Fixed ResultSet.getShort() for UNSIGNED TINYINT returns incorrect values when using server-side prepared statements. (Bug #20306) * ReplicationDriver does not always round-robin load balance depending on URL used for slaves list. (Bug #19993) * Fixed calling toString() on ResultSetMetaData for driver-generated (that is, from DatabaseMetaData method calls, or from getGeneratedKeys()) result sets would raise a NullPointerException. (Bug #19993) * Connection fails to localhost when using timeout and IPv6 is configured. (Bug #19726) * ResultSet.getFloatFromString() can't retrieve values near Float.MIN/MAX_VALUE. (Bug #18880) * Fixed memory leak with profileSQL=true. (Bug #16987) * Fixed NullPointerException in MysqlDataSourceFactory due to Reference containing RefAddrs with null content. (Bug #16791)  File: manual.info, Node: cj-news-3-1-13, Next: cj-news-3-1-12, Prev: cj-news-3-1-14, Up: cg-news-3-1 D.6.3.3 Changes in MySQL Connector/J 3.1.13 (26 May 2006) ......................................................... *Bugs fixed:* * `Fixed PreparedStatement.setObject(int, Object, int)' doesn't respect scale of BigDecimals. (Bug #19615) * Fixed `ResultSet.wasNull()' returns incorrect value when extracting native string from server-side prepared statement generated result set. (Bug #19282) * Fixed invalid classname returned for `ResultSetMetaData.getColumnClassName()' for `BIGINT type'. (Bug #19282) * Fixed case where driver wasn't reading server status correctly when fetching server-side prepared statement rows, which in some cases could cause warning counts to be off, or multiple result sets to not be read off the wire. (Bug #19282) * Fixed data truncation and `getWarnings()' only returns last warning in set. (Bug #18740) * Fixed aliased column names where length of name > 251 are corrupted. (Bug #18554) * Improved performance of retrieving `BigDecimal', `Time', `Timestamp' and `Date' values from server-side prepared statements by creating fewer short-lived instances of `Strings' when the native type is not an exact match for the requested type. (Bug #18496) * Added performance feature, re-writing of batched executes for `Statement.executeBatch()' (for all DML statements) and `PreparedStatement.executeBatch()' (for INSERTs with VALUE clauses only). Enable by using "rewriteBatchedStatements=true" in your JDBC URL. (Bug #18041) * Fixed issue where server-side prepared statements don't cause truncation exceptions to be thrown when truncation happens. (Bug #18041) * Fixed `CallableStatement.registerOutParameter()' not working when some parameters pre-populated. Still waiting for feedback from JDBC experts group to determine what correct parameter count from `getMetaData()' should be, however. (Bug #17898) * Fixed calling `clearParameters()' on a closed prepared statement causes NPE. (Bug #17587) * Map "latin1" on MySQL server to CP1252 for MySQL > 4.1.0. (Bug #17587) * Added additional accessor and mutator methods on ConnectionProperties so that DataSource users can use same naming as regular URL properties. (Bug #17587) * Fixed `ResultSet.wasNull()' not always reset correctly for booleans when done using conversion for server-side prepared statements. (Bug #17450) * Fixed `Statement.getGeneratedKeys()' throws `NullPointerException' when no query has been processed. (Bug #17099) * Fixed updatable result set doesn't return `AUTO_INCREMENT' values for `insertRow()' when multiple column primary keys are used. (the driver was checking for the existence of single-column primary keys and an autoincrement value > 0 instead of a straightforward `isAutoIncrement()' check). (Bug #16841) * `DBMD.getColumns()' returns wrong type for *Note `BIT': numeric-types. (Bug #15854) * `lib-nodist' directory missing from package breaks out-of-box build. (Bug #15676) * Fixed issue with `ReplicationConnection' incorrectly copying state, doesn't transfer connection context correctly when transitioning between the same read-only states. (Bug #15570) * No "dos" character set in MySQL > 4.1.0. (Bug #15544) * `INOUT' parameter does not store `IN' value. (Bug #15464) * `PreparedStatement.setObject()' serializes `BigInteger' as object, rather than sending as numeric value (and is thus not complementary to `.getObject()' on an `UNSIGNED LONG' type). (Bug #15383) * Fixed issue where driver was unable to initialize character set mapping tables. Removed reliance on `.properties' files to hold this information, as it turns out to be too problematic to code around class loader hierarchies that change depending on how an application is deployed. Moved information back into the `CharsetMapping' class. (Bug #14938) * Exception thrown for new decimal type when using updatable result sets. (Bug #14609) * Driver now aware of fix for *Note `BIT': numeric-types. type metadata that went into MySQL-5.0.21 for server not reporting length consistently . (Bug #13601) * Added support for Apache Commons logging, use "com.mysql.jdbc.log.CommonsLogger" as the value for the "logger" configuration property. (Bug #13469) * Fixed driver trying to call methods that don't exist on older and newer versions of Log4j. The fix is not trying to auto-detect presence of log4j, too many different incompatible versions out there in the wild to do this reliably. If you relied on autodetection before, you will need to add "logger=com.mysql.jdbc.log.Log4JLogger" to your JDBC URL to enable Log4J usage, or alternatively use the new "CommonsLogger" class to take care of this. (Bug #13469) * LogFactory now prepends `com.mysql.jdbc.log' to the log class name if it cannot be found as specified. This enables you to use `short names' for the built-in log factories, for example, `logger=CommonsLogger' instead of `logger=com.mysql.jdbc.log.CommonsLogger'. (Bug #13469) * `ResultSet.getShort()' for `UNSIGNED TINYINT' returned wrong values. (Bug #11874)  File: manual.info, Node: cj-news-3-1-12, Next: cj-news-3-1-11, Prev: cj-news-3-1-13, Up: cg-news-3-1 D.6.3.4 Changes in MySQL Connector/J 3.1.12 (30 November 2005) .............................................................. *Bugs fixed:* * Process escape tokens in `Connection.prepareStatement(...)'. You can disable this behavior by setting the JDBC URL configuration property `processEscapeCodesForPrepStmts' to `false'. (Bug #15141) * Usage advisor complains about unreferenced columns, even though they've been referenced. (Bug #15065) * Driver incorrectly closes streams passed as arguments to `PreparedStatements'. Reverts to legacy behavior by setting the JDBC configuration property `autoClosePStmtStreams' to `true' (also included in the 3-0-Compat configuration `bundle'). (Bug #15024) * Deadlock while closing server-side prepared statements from multiple threads sharing one connection. (Bug #14972) * Unable to initialize character set mapping tables (due to J2EE classloader differences). (Bug #14938) * Escape processor replaces quote character in quoted string with string delimiter. (Bug #14909) * `DatabaseMetaData.getColumns()' doesn't return `TABLE_NAME' correctly. (Bug #14815) * `storesMixedCaseIdentifiers()' returns `false' (Bug #14562) * `storesLowerCaseIdentifiers()' returns `true' (Bug #14562) * `storesMixedCaseQuotedIdentifiers()' returns `false' (Bug #14562) * `storesMixedCaseQuotedIdentifiers()' returns `true' (Bug #14562) * If `lower_case_table_names=0' (on server): * `storesLowerCaseIdentifiers()' returns `false' * `storesLowerCaseQuotedIdentifiers()' returns `false' * `storesMixedCaseIdentifiers()' returns `true' * `storesMixedCaseQuotedIdentifiers()' returns `true' * `storesUpperCaseIdentifiers()' returns `false' * `storesUpperCaseQuotedIdentifiers()' returns `true' (Bug #14562) * `storesUpperCaseIdentifiers()' returns `false' (Bug #14562) * `storesUpperCaseQuotedIdentifiers()' returns `true' (Bug #14562) * If `lower_case_table_names=1' (on server): * `storesLowerCaseIdentifiers()' returns `true' * `storesLowerCaseQuotedIdentifiers()' returns `true' * `storesMixedCaseIdentifiers()' returns `false' * `storesMixedCaseQuotedIdentifiers()' returns `false' * `storesUpperCaseIdentifiers()' returns `false' * `storesUpperCaseQuotedIdentifiers()' returns `true' (Bug #14562) * `storesLowerCaseQuotedIdentifiers()' returns `true' (Bug #14562) * Fixed `DatabaseMetaData.stores*Identifiers()': * If `lower_case_table_names=0' (on server): * `storesLowerCaseIdentifiers()' returns `false' * `storesLowerCaseQuotedIdentifiers()' returns `false' * `storesMixedCaseIdentifiers()' returns `true' * `storesMixedCaseQuotedIdentifiers()' returns `true' * `storesUpperCaseIdentifiers()' returns `false' * `storesUpperCaseQuotedIdentifiers()' returns `true' * If `lower_case_table_names=1' (on server): * `storesLowerCaseIdentifiers()' returns `true' * `storesLowerCaseQuotedIdentifiers()' returns `true' * `storesMixedCaseIdentifiers()' returns `false' * `storesMixedCaseQuotedIdentifiers()' returns `false' * `storesUpperCaseIdentifiers()' returns `false' * `storesUpperCaseQuotedIdentifiers()' returns `true' (Bug #14562) * `storesMixedCaseIdentifiers()' returns `true' (Bug #14562) * `storesLowerCaseQuotedIdentifiers()' returns `false' (Bug #14562) * Java type conversion may be incorrect for *Note `MEDIUMINT': numeric-types. (Bug #14562) * `storesLowerCaseIdentifiers()' returns `false' (Bug #14562) * Added configuration property `useGmtMillisForDatetimes' which when set to `true' causes `ResultSet.getDate()', `.getTimestamp()' to return correct millis-since GMT when `.getTime()' is called on the return value (currently default is `false' for legacy behavior). (Bug #14562) * Extraneous sleep on `autoReconnect'. (Bug #13775) * Reconnect during middle of `executeBatch()' should not occur if `autoReconnect' is enabled. (Bug #13255) * `maxQuerySizeToLog' is not respected. Added logging of bound values for `execute()' phase of server-side prepared statements when `profileSQL=true' as well. (Bug #13048) * OpenOffice expects `DBMD.supportsIntegrityEnhancementFacility()' to return `true' if foreign keys are supported by the datasource, even though this method also covers support for check constraints, which MySQL _doesn't_ have. Setting the configuration property `overrideSupportsIntegrityEnhancementFacility' to `true' causes the driver to return `true' for this method. (Bug #12975) * Added `com.mysql.jdbc.testsuite.url.default' system property to set default JDBC url for testsuite (to speed up bug resolution when I'm working in Eclipse). (Bug #12975) * `logSlowQueries' should give better info. (Bug #12230) * Don't increase timeout for failover/reconnect. (Bug #6577) * Fixed client-side prepared statement bug with embedded `?' characters inside quoted identifiers (it was recognized as a placeholder, when it was not). * Do not permit `executeBatch()' for `CallableStatements' with registered `OUT'/`INOUT' parameters (JDBC compliance). * Fall back to platform-encoding for `URLDecoder.decode()' when parsing driver URL properties if the platform doesn't have a two-argument version of this method.  File: manual.info, Node: cj-news-3-1-11, Next: cj-news-3-1-10, Prev: cj-news-3-1-12, Up: cg-news-3-1 D.6.3.5 Changes in MySQL Connector/J 3.1.11 (07 October 2005) ............................................................. *Bugs fixed:* * The configuration property `sessionVariables' now permits you to specify variables that start with the ``@'' sign. (Bug #13453) * URL configuration parameters do not permit ``&'' or ``='' in their values. The JDBC driver now parses configuration parameters as if they are encoded using the application/x-www-form-urlencoded format as specified by `java.net.URLDecoder' (`http://java.sun.com/j2se/1.5.0/docs/api/java/net/URLDecoder.html'). If the ``%'' character is present in a configuration property, it must now be represented as `%25', which is the encoded form of ``%'' when using application/x-www-form-urlencoded encoding. (Bug #13453) * Workaround for Bug#13374: `ResultSet.getStatement()' on closed result set returns `NULL' (as per JDBC 4.0 spec, but not backward-compatible). Set the connection property `retainStatementAfterResultSetClose' to `true' to be able to retrieve a `ResultSet''s statement after the `ResultSet' has been closed using `.getStatement()' (the default is `false', to be JDBC-compliant and to reduce the chance that code using JDBC leaks `Statement' instances). (Bug #13277) * `ResultSetMetaData' from `Statement.getGeneratedKeys()' caused a `NullPointerException' to be thrown whenever a method that required a connection reference was called. (Bug #13277) * Backport of `VAR[BINARY|CHAR] [BINARY]' types detection from 5.0 branch. (Bug #13277) * Fixed `NullPointerException' when converting `catalog' parameter in many `DatabaseMetaDataMethods' to `byte[]'s (for the result set) when the parameter is `null'. (`null' is not technically permitted by the JDBC specification, but we have historically permitted it). (Bug #13277) * Backport of `Field' class, `ResultSetMetaData.getColumnClassName()', and `ResultSet.getObject(int)' changes from 5.0 branch to fix behavior surrounding `VARCHAR BINARY'/*Note `VARBINARY': binary-varbinary. and related types. (Bug #13277) * Read response in `MysqlIO.sendFileToServer()', even if the local file can't be opened, otherwise next query issued will fail, because it is reading the response to the empty *Note `LOAD DATA INFILE': load-data. packet sent to the server. (Bug #13277) * When `gatherPerfMetrics' is enabled for servers older than 4.1.0, a `NullPointerException' is thrown from the constructor of `ResultSet' if the query doesn't use any tables. (Bug #13043) * `java.sql.Types.OTHER' returned for *Note `BINARY': binary-varbinary. and *Note `VARBINARY': binary-varbinary. columns when using `DatabaseMetaData.getColumns()'. (Bug #12970) * `ServerPreparedStatement.getBinding()' now checks if the statement is closed before attempting to reference the list of parameter bindings, to avoid throwing a `NullPointerException'. (Bug #12970) * Tokenizer for `=' in URL properties was causing `sessionVariables=....' to be parameterized incorrectly. (Bug #12753) * `cp1251' incorrectly mapped to `win1251' for servers newer than 4.0.x. (Bug #12752) * `getExportedKeys()' (Bug #12541) * Specifying a catalog works as stated in the API docs. (Bug #12541) * Specifying `NULL' means that catalog will not be used to filter the results (thus all databases will be searched), unless you've set `nullCatalogMeansCurrent=true' in your JDBC URL properties. (Bug #12541) * `getIndexInfo()' (Bug #12541) * `getProcedures()' (and thus indirectly `getProcedureColumns()') (Bug #12541) * `getImportedKeys()' (Bug #12541) * Specifying `""' means `current' catalog, even though this isn't quite JDBC spec compliant, it is there for legacy users. (Bug #12541) * `getCrossReference()' (Bug #12541) * Added `Connection.isMasterConnection()' for clients to be able to determine if a multi-host master/slave connection is connected to the first host in the list. (Bug #12541) * `getColumns()' (Bug #12541) * Handling of catalog argument in `DatabaseMetaData.getIndexInfo()', which also means changes to the following methods in `DatabaseMetaData': * `getBestRowIdentifier()' * `getColumns()' * `getCrossReference()' * `getExportedKeys()' * `getImportedKeys()' * `getIndexInfo()' * `getPrimaryKeys()' * `getProcedures()' (and thus indirectly `getProcedureColumns()') * `getTables()' The `catalog' argument in all of these methods now behaves in the following way: * Specifying `NULL' means that catalog will not be used to filter the results (thus all databases will be searched), unless you've set `nullCatalogMeansCurrent=true' in your JDBC URL properties. * Specifying `""' means `current' catalog, even though this isn't quite JDBC spec compliant, it is there for legacy users. * Specifying a catalog works as stated in the API docs. * Made `Connection.clientPrepare()' available from `wrapped' connections in the `jdbc2.optional' package (connections built by `ConnectionPoolDataSource' instances). (Bug #12541) * `getBestRowIdentifier()' (Bug #12541) * Made `Connection.clientPrepare()' available from `wrapped' connections in the `jdbc2.optional' package (connections built by `ConnectionPoolDataSource' instances). (Bug #12541) * `getTables()' (Bug #12541) * `getPrimaryKeys()' (Bug #12541) * `Connection.prepareCall()' is database name case-sensitive (on Windows systems). (Bug #12417) * `explainSlowQueries' hangs with server-side prepared statements. (Bug #12229) * Properties shared between master and slave with replication connection. (Bug #12218) * Geometry types not handled with server-side prepared statements. (Bug #12104) * `maxPerformance.properties' mis-spells `elideSetAutoCommits'. (Bug #11976) * `ReplicationConnection' won't switch to slave, throws `Catalog can't be null' exception. (Bug #11879) * `Pstmt.setObject(...., Types.BOOLEAN)' throws exception. (Bug #11798) * Escape tokenizer doesn't respect stacked single quotation marks for escapes. (Bug #11797) * `GEOMETRY' type not recognized when using server-side prepared statements. (Bug #11797) * Foreign key information that is quoted is parsed incorrectly when `DatabaseMetaData' methods use that information. (Bug #11781) * The `sendBlobChunkSize' property is now clamped to `max_allowed_packet' with consideration of stream buffer size and packet headers to avoid `PacketTooBigExceptions' when `max_allowed_packet' is similar in size to the default `sendBlobChunkSize' which is 1M. (Bug #11781) * `CallableStatement.clearParameters()' now clears resources associated with `INOUT'/`OUTPUT' parameters as well as `INPUT' parameters. (Bug #11781) * Fixed regression caused by fix for Bug#11552 that caused driver to return incorrect values for unsigned integers when those integers where within the range of the positive signed type. (Bug #11663) * Moved source code to Subversion repository. (Bug #11663) * Incorrect generation of testcase scripts for server-side prepared statements. (Bug #11663) * Fixed statements generated for testcases missing `;' for `plain' statements. (Bug #11629) * Spurious `!' on console when character encoding is `utf8'. (Bug #11629) * `StringUtils.getBytes()' doesn't work when using multi-byte character encodings and a length in _characters_ is specified. (Bug #11614) * `DBMD.storesLower/Mixed/UpperIdentifiers()' reports incorrect values for servers deployed on Windows. (Bug #11575) * Reworked `Field' class, `*Buffer', and `MysqlIO' to be aware of field lengths > `Integer.MAX_VALUE'. (Bug #11498) * Escape processor didn't honor strings demarcated with double quotation marks. (Bug #11498) * Updated `DBMD.supportsCorrelatedQueries()' to return `true' for versions > 4.1, `supportsGroupByUnrelated()' to return `true' and `getResultSetHoldability()' to return `HOLD_CURSORS_OVER_COMMIT'. (Bug #11498) * Lifted restriction of changing streaming parameters with server-side prepared statements. As long as `all' streaming parameters were set before execution, `.clearParameters()' does not have to be called. (due to limitation of client/server protocol, prepared statements can not reset _individual_ stream data on the server side). (Bug #11498) * `ResultSet.moveToCurrentRow()' fails to work when preceded by a call to `ResultSet.moveToInsertRow()'. (Bug #11190) * *Note `VARBINARY': binary-varbinary. data corrupted when using server-side prepared statements and `.setBytes()'. (Bug #11115) * `Statement.getWarnings()' fails with NPE if statement has been closed. (Bug #10630) * Only get `char[]' from SQL in `PreparedStatement.ParseInfo()' when needed. (Bug #10630)  File: manual.info, Node: cj-news-3-1-10, Next: cj-news-3-1-9, Prev: cj-news-3-1-11, Up: cg-news-3-1 D.6.3.6 Changes in MySQL Connector/J 3.1.10 (23 June 2005) .......................................................... *Bugs fixed:* * Initial implemention of `ParameterMetadata' for `PreparedStatement.getParameterMetadata()'. Only works fully for `CallableStatements', as current server-side prepared statements return every parameter as a *Note `VARCHAR': char. type. * Fixed connecting without a database specified raised an exception in `MysqlIO.changeDatabaseTo()'.  File: manual.info, Node: cj-news-3-1-9, Next: cj-news-3-1-8, Prev: cj-news-3-1-10, Up: cg-news-3-1 D.6.3.7 Changes in MySQL Connector/J 3.1.9 (22 June 2005) ......................................................... *Bugs fixed:* * Production package doesn't include JBoss integration classes. (Bug #11411) * Removed nonsensical `costly type conversion' warnings when using usage advisor. (Bug #11411) * Fixed `PreparedStatement.setClob()' not accepting `null' as a parameter. (Bug #11360) * Connector/J dumping query into `SQLException' twice. (Bug #11360) * `autoReconnect' ping causes exception on connection startup. (Bug #11259) * `Connection.setCatalog()' is now aware of the `useLocalSessionState' configuration property, which when set to `true' will prevent the driver from sending `USE ...' to the server if the requested catalog is the same as the current catalog. (Bug #11115) * `3-0-Compat': Compatibility with Connector/J 3.0.x functionality (Bug #11115) * `maxPerformance': Maximum performance without being reckless (Bug #11115) * `solarisMaxPerformance': Maximum performance for Solaris, avoids syscalls where it can (Bug #11115) * Added `maintainTimeStats' configuration property (defaults to `true'), which tells the driver whether or not to keep track of the last query time and the last successful packet sent to the server's time. If set to `false', removes two syscalls per query. (Bug #11115) * *Note `VARBINARY': binary-varbinary. data corrupted when using server-side prepared statements and `ResultSet.getBytes()'. (Bug #11115) * Added the following configuration bundles, use one or many using the `useConfigs' configuration property: * `maxPerformance': Maximum performance without being reckless * `solarisMaxPerformance': Maximum performance for Solaris, avoids syscalls where it can * `3-0-Compat': Compatibility with Connector/J 3.0.x functionality (Bug #11115) * Try to handle `OutOfMemoryErrors' more gracefully. Although not much can be done, they will in most cases close the connection they happened on so that further operations don't run into a connection in some unknown state. When an OOM has happened, any further operations on the connection will fail with a `Connection closed' exception that will also list the OOM exception as the reason for the implicit connection close event. (Bug #10850) * Setting `cachePrepStmts=true' now causes the `Connection' to also cache the check the driver performs to determine if a prepared statement can be server-side or not, as well as caches server-side prepared statements for the lifetime of a connection. As before, the `prepStmtCacheSize' parameter controls the size of these caches. (Bug #10850) * Don't send `COM_RESET_STMT' for each execution of a server-side prepared statement if it isn't required. (Bug #10850) * 0-length streams not sent to server when using server-side prepared statements. (Bug #10850) * Driver detects if you're running MySQL-5.0.7 or later, and does not scan for `LIMIT ?[,?]' in statements being prepared, as the server supports those types of queries now. (Bug #10850) * Reorganized directory layout. Sources now are in `src' folder. Don't pollute parent directory when building, now output goes to `./build', distribution goes to `./dist'. (Bug #10496) * Added support/bug hunting feature that generates `.sql' test scripts to `STDERR' when `autoGenerateTestcaseScript' is set to `true'. (Bug #10496) * `SQLException' is thrown when using property `characterSetResults' with `cp932' or `eucjpms'. (Bug #10496) * The data type returned for `TINYINT(1)' columns when `tinyInt1isBit=true' (the default) can be switched between `Types.BOOLEAN' and `Types.BIT' using the new configuration property `transformedBitIsBoolean', which defaults to `false'. If set to `false' (the default), `DatabaseMetaData.getColumns()' and `ResultSetMetaData.getColumnType()' will return `Types.BOOLEAN' for `TINYINT(1)' columns. If `true', `Types.BOOLEAN' will be returned instead. Regardless of this configuration property, if `tinyInt1isBit' is enabled, columns with the type `TINYINT(1)' will be returned as `java.lang.Boolean' instances from `ResultSet.getObject(...)', and `ResultSetMetaData.getColumnClassName()' will return `java.lang.Boolean'. (Bug #10485) * `SQLException' thrown when retrieving `YEAR(2)' with `ResultSet.getString()'. The driver will now always treat *Note `YEAR': year. types as `java.sql.Dates' and return the correct values for `getString()'. Alternatively, the `yearIsDateType' connection property can be set to `false' and the values will be treated as `SHORT's. (Bug #10485) * Driver doesn't support `{?=CALL(...)}' for calling stored functions. This involved adding support for function retrieval to `DatabaseMetaData.getProcedures()' and `getProcedureColumns()' as well. (Bug #10310) * Unsigned *Note `SMALLINT': numeric-types. treated as signed for `ResultSet.getInt()', fixed all cases for `UNSIGNED' integer values and server-side prepared statements, as well as `ResultSet.getObject()' for `UNSIGNED TINYINT'. (Bug #10156) * Made `ServerPreparedStatement.asSql()' work correctly so auto-explain functionality would work with server-side prepared statements. (Bug #10155) * Double quotation marks not recognized when parsing client-side prepared statements. (Bug #10155) * Made JDBC2-compliant wrappers public to enable access to vendor extensions. (Bug #10155) * `DatabaseMetaData.supportsMultipleOpenResults()' now returns `true'. The driver has supported this for some time, DBMD just missed that fact. (Bug #10155) * Cleaned up logging of profiler events, moved code to dump a profiler event as a string to `com.mysql.jdbc.log.LogUtils' so that third parties can use it. (Bug #10155) * Made `enableStreamingResults()' visible on `com.mysql.jdbc.jdbc2.optional.StatementWrapper'. (Bug #10155) * Actually write manifest file to correct place so it ends up in the binary jar file. (Bug #10144) * Added `createDatabaseIfNotExist' property (default is `false'), which will cause the driver to ask the server to create the database specified in the URL if it doesn't exist. You must have the appropriate privileges for database creation for this to work. (Bug #10144) * Memory leak in `ServerPreparedStatement' if `serverPrepare()' fails. (Bug #10144) * `com.mysql.jdbc.PreparedStatement.ParseInfo' does unnecessary call to `toCharArray()'. (Bug #9064) * Driver now correctly uses CP932 if available on the server for Windows-31J, CP932 and MS932 java encoding names, otherwise it resorts to SJIS, which is only a close approximation. Currently only MySQL-5.0.3 and newer (and MySQL-4.1.12 or .13, depending on when the character set gets backported) can reliably support any variant of CP932. * Overhaul of character set configuration, everything now lives in a properties file.  File: manual.info, Node: cj-news-3-1-8, Next: cj-news-3-1-7, Prev: cj-news-3-1-9, Up: cg-news-3-1 D.6.3.8 Changes in MySQL Connector/J 3.1.8 (14 April 2005) .......................................................... *Bugs fixed:* * Should accept `null' for catalog (meaning use current) in DBMD methods, even though it is not JDBC-compliant for legacy's sake. Disable by setting connection property `nullCatalogMeansCurrent' to `false' (which will be the default value in C/J 3.2.x). (Bug #9917) * Fixed driver not returning `true' for `-1' when `ResultSet.getBoolean()' was called on result sets returned from server-side prepared statements. (Bug #9778) * Added a `Manifest.MF' file with implementation information to the `.jar' file. (Bug #9778) * More tests in `Field.isOpaqueBinary()' to distinguish opaque binary (that is, fields with type `CHAR(n)' and `CHARACTER SET BINARY') from output of various scalar and aggregate functions that return strings. (Bug #9778) * `DBMD.getTables()' shouldn't return tables if views are asked for, even if the database version doesn't support views. (Bug #9778) * Should accept `null' for name patterns in DBMD (meaning ``%''), even though it isn't JDBC compliant, for legacy's sake. Disable by setting connection property `nullNamePatternMatchesAll' to `false' (which will be the default value in C/J 3.2.x). (Bug #9769) * The performance metrics feature now gathers information about number of tables referenced in a SELECT. (Bug #9704) * The logging system is now automatically configured. If the value has been set by the user, using the URL property `logger' or the system property `com.mysql.jdbc.logger', then use that, otherwise, autodetect it using the following steps: 1. Log4j, if it is available, 2. Then JDK1.4 logging, 3. Then fallback to our `STDERR' logging. (Bug #9704) * `Statement.getMoreResults()' could throw NPE when existing result set was `.close()'d. (Bug #9704) * Stored procedures with *Note `DECIMAL': numeric-types. parameters with storage specifications that contained ``,'' in them would fail. (Bug #9682) * `PreparedStatement.setObject(int, Object, int type, int scale)' now uses scale value for `BigDecimal' instances. (Bug #9682) * Added support for the c3p0 connection pool's (`http://c3p0.sf.net/') validation/connection checker interface which uses the lightweight `COM_PING' call to the server if available. To use it, configure your c3p0 connection pool's `connectionTesterClassName' property to use `com.mysql.jdbc.integration.c3p0.MysqlConnectionTester'. (Bug #9320) * `PreparedStatement.getMetaData()' inserts blank row in database under certain conditions when not using server-side prepared statements. (Bug #9320) * Better detection of `LIMIT' inside/outside of quoted strings so that the driver can more correctly determine whether a prepared statement can be prepared on the server or not. (Bug #9320) * `Connection.canHandleAsPreparedStatement()' now makes `best effort' to distinguish `LIMIT' clauses with placeholders in them from ones without to have fewer false positives when generating work-arounds for statements the server cannot currently handle as server-side prepared statements. (Bug #9320) * Fixed `build.xml' to not compile `log4j' logging if `log4j' not available. (Bug #9320) * Added finalizers to `ResultSet' and `Statement' implementations to be JDBC spec-compliant, which requires that if not explicitly closed, these resources should be closed upon garbage collection. (Bug #9319) * Stored procedures with same name in different databases confuse the driver when it tries to determine parameter counts/types. (Bug #9319) * A continuation of Bug#8868, where functions used in queries that should return nonstring types when resolved by temporary tables suddenly become opaque binary strings (work-around for server limitation). Also fixed fields with type of `CHAR(n) CHARACTER SET BINARY' to return correct/matching classes for `RSMD.getColumnClassName()' and `ResultSet.getObject()'. (Bug #9236) * Cannot use `UTF-8' for characterSetResults configuration property. (Bug #9206) * `PreparedStatement.addBatch()' doesn't work with server-side prepared statements and streaming *Note `BINARY': binary-varbinary. data. (Bug #9040) * `ServerPreparedStatements' now correctly `stream' *Note `BLOB': blob./`CLOB' data to the server. You can configure the threshold chunk size using the JDBC URL property `blobSendChunkSize' (the default is 1MB). (Bug #8868) * `DATE_FORMAT()' queries returned as *Note `BLOB': blob.s from `getObject()'. (Bug #8868) * Server-side session variables can be preset at connection time by passing them as a comma-delimited list for the connection property `sessionVariables'. (Bug #8868) * `BlobFromLocator' now uses correct identifier quoting when generating prepared statements. (Bug #8868) * Fixed regression in `ping()' for users using `autoReconnect=true'. (Bug #8868) * Check for empty strings (`''') when converting *Note `CHAR': char./*Note `VARCHAR': char. column data to numbers, throw exception if `emptyStringsConvertToZero' configuration property is set to `false' (for backward-compatibility with 3.0, it is now set to `true' by default, but will most likely default to `false' in 3.2). (Bug #8803) * `DATA_TYPE' column from `DBMD.getBestRowIdentifier()' causes `ArrayIndexOutOfBoundsException' when accessed (and in fact, didn't return any value). (Bug #8803) * `DBMD.supportsMixedCase*Identifiers()' returns wrong value on servers running on case-sensitive file systems. (Bug #8800) * `DBMD.supportsResultSetConcurrency()' not returning `true' for forward-only/read-only result sets (we obviously support this). (Bug #8792) * Fixed `ResultSet.getTime()' on a `NULL' value for server-side prepared statements throws NPE. * Made `Connection.ping()' a public method. * Added support for new precision-math *Note `DECIMAL': numeric-types. type in MySQL 5.0.3 and up. * Fixed `DatabaseMetaData.getTables()' returning views when they were not asked for as one of the requested table types.  File: manual.info, Node: cj-news-3-1-7, Next: cj-news-3-1-6, Prev: cj-news-3-1-8, Up: cg-news-3-1 D.6.3.9 Changes in MySQL Connector/J 3.1.7 (18 February 2005) ............................................................. *Bugs fixed:* * `PreparedStatements' not creating streaming result sets. (Bug #8487) * Don't pass `NULL' to `String.valueOf()' in `ResultSet.getNativeConvertToString()', as it stringifies it (that is, returns `null'), which is not correct for the method in question. (Bug #8487) * Fixed NPE in `ResultSet.realClose()' when using usage advisor and result set was already closed. (Bug #8428) * `ResultSet.getString()' doesn't maintain format stored on server, bug fix only enabled when `noDatetimeStringSync' property is set to `true' (the default is `false'). (Bug #8428) * Added support for *Note `BIT': numeric-types. type in MySQL-5.0.3. The driver will treat `BIT(1-8)' as the JDBC standard *Note `BIT': numeric-types. type (which maps to `java.lang.Boolean'), as the server does not currently send enough information to determine the size of a bitfield when < 9 bits are declared. `BIT(>9)' will be treated as *Note `VARBINARY': binary-varbinary, and will return `byte[]' when `getObject()' is called. (Bug #8424) * Added `useLocalSessionState' configuration property, when set to `true' the JDBC driver trusts that the application is well-behaved and only sets autocommit and transaction isolation levels using the methods provided on `java.sql.Connection', and therefore can manipulate these values in many cases without incurring round-trips to the database server. (Bug #8424) * Added `enableStreamingResults()' to `Statement' for connection pool implementations that check `Statement.setFetchSize()' for specification-compliant values. Call `Statement.setFetchSize(>=0)' to disable the streaming results for that statement. (Bug #8424) * `ResultSet.getBigDecimal()' throws exception when rounding would need to occur to set scale. The driver now chooses a rounding mode of `half up' if nonrounding `BigDecimal.setScale()' fails. (Bug #8424) * Fixed synchronization issue with `ServerPreparedStatement.serverPrepare()' that could cause deadlocks/crashes if connection was shared between threads. (Bug #8096) * Emulated locators corrupt binary data when using server-side prepared statements. (Bug #8096) * Infinite recursion when `falling back' to master in failover configuration. (Bug #7952) * Disable multi-statements (if enabled) for MySQL-4.1 versions prior to version 4.1.10 if the query cache is enabled, as the server returns wrong results in this configuration. (Bug #7952) * Removed `dontUnpackBinaryResults' functionality, the driver now always stores results from server-side prepared statements as is from the server and unpacks them on demand. (Bug #7952) * Fixed duplicated code in `configureClientCharset()' that prevented `useOldUTF8Behavior=true' from working properly. (Bug #7952) * Added `holdResultsOpenOverStatementClose' property (default is `false'), that keeps result sets open over statement.close() or new execution on same statement (suggested by Kevin Burton). (Bug #7715) * Detect new `sql_mode' variable in string form (it used to be integer) and adjust quoting method for strings appropriately. (Bug #7715) * Timestamps converted incorrectly to strings with server-side prepared statements and updatable result sets. (Bug #7715) * Timestamp key column data needed `_binary' stripped for `UpdatableResultSet.refreshRow()'. (Bug #7686) * Choose correct `direction' to apply time adjustments when both client and server are in GMT time zone when using `ResultSet.get(..., cal)' and `PreparedStatement.set(...., cal)'. (Bug #4718) * Remove `_binary' introducer from parameters used as in/out parameters in `CallableStatement'. (Bug #4718) * Always return `byte[]'s for output parameters registered as `*BINARY'. (Bug #4718) * By default, the driver now scans SQL you are preparing using all variants of `Connection.prepareStatement()' to determine if it is a supported type of statement to prepare on the server side, and if it is not supported by the server, it instead prepares it as a client-side emulated prepared statement. You can disable this by passing `emulateUnsupportedPstmts=false' in your JDBC URL. (Bug #4718) * Added `dontTrackOpenResources' option (default is `false', to be JDBC compliant), which helps with memory use for nonwell-behaved apps (that is, applications that don't close `Statement' objects when they should). (Bug #4718) * Send correct value for `boolean' `true' to server for `PreparedStatement.setObject(n, "true", Types.BIT)'. (Bug #4718) * Fixed bug with Connection not caching statements from `prepareStatement()' when the statement wasn't a server-side prepared statement. (Bug #4718)  File: manual.info, Node: cj-news-3-1-6, Next: cj-news-3-1-5, Prev: cj-news-3-1-7, Up: cg-news-3-1 D.6.3.10 Changes in MySQL Connector/J 3.1.6 (23 December 2004) .............................................................. *Bugs fixed:* * `DBMD.getProcedures()' doesn't respect catalog parameter. (Bug #7026) * Fixed hang on `SocketInputStream.read()' with `Statement.setMaxRows()' and multiple result sets when driver has to truncate result set directly, rather than tacking a `LIMIT N' on the end of it.  File: manual.info, Node: cj-news-3-1-5, Next: cj-news-3-1-4, Prev: cj-news-3-1-6, Up: cg-news-3-1 D.6.3.11 Changes in MySQL Connector/J 3.1.5 (02 December 2004) .............................................................. *Bugs fixed:* * Use 1MB packet for sending file for *Note `LOAD DATA LOCAL INFILE': load-data. if that is < `max_allowed_packet' on server. (Bug #6537) * `SUM()' on *Note `DECIMAL': numeric-types. with server-side prepared statement ignores scale if zero-padding is needed (this ends up being due to conversion to *Note `DOUBLE': numeric-types. by server, which when converted to a string to parse into `BigDecimal', loses all `padding' zeros). (Bug #6537) * Use `DatabaseMetaData.getIdentifierQuoteString()' when building DBMD queries. (Bug #6537) * Use our own implementation of buffered input streams to get around blocking behavior of `java.io.BufferedInputStream'. Disable this with `useReadAheadInput=false'. (Bug #6399) * Make auto-deserialization of `java.lang.Objects' stored in *Note `BLOB': blob. columns configurable using `autoDeserialize' property (defaults to `false'). (Bug #6399) * `ResultSetMetaData.getColumnDisplaySize()' returns incorrect values for multi-byte charsets. (Bug #6399) * Re-work `Field.isOpaqueBinary()' to detect `CHAR(N) CHARACTER SET BINARY' to support fixed-length binary fields for `ResultSet.getObject()'. (Bug #6399) * Failing to connect to the server when one of the addresses for the given host name is IPV6 (which the server does not yet bind on). The driver now loops through _all_ IP addresses for a given host, and stops on the first one that `accepts()' a `socket.connect()'. (Bug #6348) * Removed unwanted new `Throwable()' in `ResultSet' constructor due to bad merge (caused a new object instance that was never used for every result set created). Found while profiling for Bug#6359. (Bug #6225) * `ServerSidePreparedStatement' allocating short-lived objects unnecessarily. (Bug #6225) * Use null-safe-equals for key comparisons in updatable result sets. (Bug #6225) * Fixed too-early creation of `StringBuffer' in `EscapeProcessor.escapeSQL()', also return `String' when escaping not needed (to avoid unnecessary object allocations). Found while profiling for Bug #6359. (Bug #6225) * `UNSIGNED BIGINT' unpacked incorrectly from server-side prepared statement result sets. (Bug #5729) * Added experimental configuration property `dontUnpackBinaryResults', which delays unpacking binary result set values until they're asked for, and only creates object instances for nonnumeric values (it is set to `false' by default). For some usecase/jvm combinations, this is friendlier on the garbage collector. (Bug #5706) * Don't throw exceptions for `Connection.releaseSavepoint()'. (Bug #5706) * Inefficient detection of pre-existing string instances in `ResultSet.getNativeString()'. (Bug #5706) * Use a per-session `Calendar' instance by default when decoding dates from `ServerPreparedStatements' (set to old, less performant behavior by setting property `dynamicCalendars=true'). (Bug #5706) * Fixed batched updates with server prepared statements weren't looking if the types had changed for a given batched set of parameters compared to the previous set, causing the server to return the error `Wrong arguments to mysql_stmt_execute()'. (Bug #5235) * Handle case when string representation of timestamp contains trailing ``.'' with no numbers following it. (Bug #5235) * Server-side prepared statements did not honor `zeroDateTimeBehavior' property, and would cause class-cast exceptions when using `ResultSet.getObject()', as the all-zero string was always returned. (Bug #5235) * Fix comparisons made between string constants and dynamic strings that are converted with either `toUpperCase()' or `toLowerCase()' to use `Locale.ENGLISH', as some locales `override' case rules for English. Also use `StringUtils.indexOfIgnoreCase()' instead of `.toUpperCase().indexOf()', avoids creating a very short-lived transient `String' instance.  File: manual.info, Node: cj-news-3-1-4, Next: cj-news-3-1-3, Prev: cj-news-3-1-5, Up: cg-news-3-1 D.6.3.12 Changes in MySQL Connector/J 3.1.4 (04 September 2004) ............................................................... *Bugs fixed:* * Fixed `ServerPreparedStatement' to read prepared statement metadata off the wire, even though it is currently a placeholder instead of using `MysqlIO.clearInputStream()' which didn't work at various times because data wasn't available to read from the server yet. This fixes sporadic errors users were having with `ServerPreparedStatements' throwing `ArrayIndexOutOfBoundExceptions'. (Bug #5032) * Added three ways to deal with all-zero datetimes when reading them from a `ResultSet': `exception' (the default), which throws an `SQLException' with an SQLState of `S1009'; `convertToNull', which returns `NULL' instead of the date; and `round', which rounds the date to the nearest closest value which is `'0001-01-01''. (Bug #5032) * The driver is more strict about truncation of numerics on `ResultSet.get*()', and will throw an `SQLException' when truncation is detected. You can disable this by setting `jdbcCompliantTruncation' to `false' (it is enabled by default, as this functionality is required for JDBC compliance). (Bug #5032) * You can now use URLs in *Note `LOAD DATA LOCAL INFILE': load-data. statements, and the driver will use Java's built-in handlers for retrieving the data and sending it to the server. This feature is not enabled by default, you must set the `allowUrlInLocalInfile' connection property to `true'. (Bug #5032) * `ResultSet.getObject()' doesn't return type `Boolean' for pseudo-bit types from prepared statements on 4.1.x (shortcut for avoiding extra type conversion when using binary-encoded result sets obscured test in `getObject()' for `pseudo' bit type). (Bug #5032) * Use `com.mysql.jdbc.Message''s classloader when loading resource bundle, should fix sporadic issues when the caller's classloader can't locate the resource bundle. (Bug #5032) * `ServerPreparedStatements' dealing with return of *Note `DECIMAL': numeric-types. type don't work. (Bug #5012) * Track packet sequence numbers if `enablePacketDebug=true', and throw an exception if packets received out-of-order. (Bug #4689) * `ResultSet.wasNull()' does not work for primatives if a previous `null' was returned. (Bug #4689) * Optimized integer number parsing, enable `old' slower integer parsing using JDK classes using `useFastIntParsing=false' property. (Bug #4642) * Added `useOnlyServerErrorMessages' property, which causes message text in exceptions generated by the server to only contain the text sent by the server (as opposed to the SQLState's `standard' description, followed by the server's error message). This property is set to `true' by default. (Bug #4642) * `ServerPreparedStatement.execute*()' sometimes threw `ArrayIndexOutOfBoundsException' when unpacking field metadata. (Bug #4642) * Connector/J 3.1.3 beta does not handle integers correctly (caused by changes to support unsigned reads in `Buffer.readInt()' -> `Buffer.readShort()'). (Bug #4510) * Added support in `DatabaseMetaData.getTables()' and `getTableTypes()' for views, which are now available in MySQL server 5.0.x. (Bug #4510) * `ResultSet.getObject()' returns wrong type for strings when using prepared statements. (Bug #4482) * Calling `MysqlPooledConnection.close()' twice (even though an application error), caused NPE. Fixed. (Bug #4482)  File: manual.info, Node: cj-news-3-1-3, Next: cj-news-3-1-2, Prev: cj-news-3-1-4, Up: cg-news-3-1 D.6.3.13 Changes in MySQL Connector/J 3.1.3 (07 July 2004) .......................................................... *Bugs fixed:* * Support new time zone variables in MySQL-4.1.3 when `useTimezone=true'. (Bug #4311) * Error in retrieval of `mediumint' column with prepared statements and binary protocol. (Bug #4311) * Support for unsigned numerics as return types from prepared statements. This also causes a change in `ResultSet.getObject()' for the `bigint unsigned' type, which used to return `BigDecimal' instances, it now returns instances of `java.lang.BigInteger'. (Bug #4311) * Externalized more messages (on-going effort). (Bug #4119) * Null bitmask sent for server-side prepared statements was incorrect. (Bug #4119) * Added constants for MySQL error numbers (publicly accessible, see `com.mysql.jdbc.MysqlErrorNumbers'), and the ability to generate the mappings of vendor error codes to SQLStates that the driver uses (for documentation purposes). (Bug #4119) * Added packet debugging code (see the `enablePacketDebug' property documentation). (Bug #4119) * Use SQL Standard SQL states by default, unless `useSqlStateCodes' property is set to `false'. (Bug #4119) * Mangle output parameter names for `CallableStatements' so they will not clash with user variable names. * Added support for `INOUT' parameters in `CallableStatements'.  File: manual.info, Node: cj-news-3-1-2, Next: cj-news-3-1-1, Prev: cj-news-3-1-3, Up: cg-news-3-1 D.6.3.14 Changes in MySQL Connector/J 3.1.2 (09 June 2004) .......................................................... *Bugs fixed:* * Don't enable server-side prepared statements for server version 5.0.0 or 5.0.1, as they aren't compatible with the '4.1.2+' style that the driver uses (the driver expects information to come back that isn't there, so it hangs). (Bug #3804) * `getWarnings()' returns `SQLWarning' instead of `DataTruncation'. (Bug #3804) * `getProcedureColumns()' doesn't work with wildcards for procedure name. (Bug #3540) * `getProcedures()' does not return any procedures in result set. (Bug #3539) * Fixed `DatabaseMetaData.getProcedures()' when run on MySQL-5.0.0 (output of *Note `SHOW PROCEDURE STATUS': show-procedure-status. changed between 5.0.0 and 5.0.1. (Bug #3520) * Added `connectionCollation' property to cause driver to issue `set collation_connection=...' query on connection init if default collation for given charset is not appropriate. (Bug #3520) * `DBMD.getSQLStateType()' returns incorrect value. (Bug #3520) * Correctly map output parameters to position given in `prepareCall()' versus. order implied during `registerOutParameter()'. (Bug #3146) * Cleaned up detection of server properties. (Bug #3146) * Correctly detect initial character set for servers >= 4.1.0. (Bug #3146) * Support placeholder for parameter metadata for server >= 4.1.2. (Bug #3146) * Added `gatherPerformanceMetrics' property, along with properties to control when/where this info gets logged (see docs for more info). * Fixed case when no parameters could cause a `NullPointerException' in `CallableStatement.setOutputParameters()'. * Enabled callable statement caching using `cacheCallableStmts' property. * Fixed sending of split packets for large queries, enabled nio ability to send large packets as well. * Added `.toString()' functionality to `ServerPreparedStatement', which should help if you're trying to debug a query that is a prepared statement (it shows SQL as the server would process). * Added `logSlowQueries' property, along with `slowQueriesThresholdMillis' property to control when a query should be considered `slow.' * Removed wrapping of exceptions in `MysqlIO.changeUser()'. * Fixed stored procedure parameter parsing info when size was specified for a parameter (for example, `char()', `varchar()'). * `ServerPreparedStatements' weren't actually de-allocating server-side resources when `.close()' was called. * Fixed case when no output parameters specified for a stored procedure caused a bogus query to be issued to retrieve out parameters, leading to a syntax error from the server.  File: manual.info, Node: cj-news-3-1-1, Next: cj-news-3-1-0, Prev: cj-news-3-1-2, Up: cg-news-3-1 D.6.3.15 Changes in MySQL Connector/J 3.1.1 (14 February 2004 alpha) .................................................................... *Bugs fixed:* * Use DocBook version of docs for shipped versions of drivers. (Bug #2671) * `NULL' fields were not being encoded correctly in all cases in server-side prepared statements. (Bug #2671) * Fixed rare buffer underflow when writing numbers into buffers for sending prepared statement execution requests. (Bug #2671) * Fixed `ConnectionProperties' that weren't properly exposed through accessors, cleaned up `ConnectionProperties' code. (Bug #2623) * Class-cast exception when using scrolling result sets and server-side prepared statements. (Bug #2623) * Merged unbuffered input code from 3.0. (Bug #2623) * Enabled streaming of result sets from server-side prepared statements. (Bug #2606) * Server-side prepared statements were not returning data type *Note `YEAR': year. correctly. (Bug #2606) * Fixed charset conversion issue in `getTables()'. (Bug #2502) * Implemented multiple result sets returned from a statement or stored procedure. (Bug #2502) * Implemented `Connection.prepareCall()', and `DatabaseMetaData'. `getProcedures()' and `getProcedureColumns()'. (Bug #2359) * Merged prepared statement caching, and `.getMetaData()' support from 3.0 branch. (Bug #2359) * Fixed off-by-1900 error in some cases for years in `TimeUtil.fastDate'/`TimeCreate()' when unpacking results from server-side prepared statements. (Bug #2359) * Reset `long binary' parameters in `ServerPreparedStatement' when `clearParameters()' is called, by sending `COM_RESET_STMT' to the server. (Bug #2359) * `NULL' values for numeric types in binary encoded result sets causing `NullPointerExceptions'. (Bug #2359) * Display where/why a connection was implicitly closed (to aid debugging). (Bug #1673) * `DatabaseMetaData.getColumns()' is not returning correct column ordinal info for non-`'%'' column name patterns. (Bug #1673) * Fixed `NullPointerException' in `ServerPreparedStatement.setTimestamp()', as well as year and month descrepencies in `ServerPreparedStatement.setTimestamp()', `setDate()'. (Bug #1673) * Added ability to have multiple database/JVM targets for compliance and regression/unit tests in `build.xml'. (Bug #1673) * Fixed sending of queries larger than 16M. (Bug #1673) * Merged fix of data type mapping from MySQL type *Note `FLOAT': numeric-types. to `java.sql.Types.REAL' from 3.0 branch. (Bug #1673) * Fixed NPE and year/month bad conversions when accessing some datetime functionality in `ServerPreparedStatements' and their resultant result sets. (Bug #1673) * Added named and indexed input/output parameter support to `CallableStatement'. MySQL-5.0.x or newer. (Bug #1673) * `CommunicationsException' implemented, that tries to determine why communications was lost with a server, and displays possible reasons when `.getMessage()' is called. (Bug #1673) * Detect collation of column for `RSMD.isCaseSensitive()'. (Bug #1673) * Optimized `Buffer.readLenByteArray()' to return shared empty byte array when length is 0. * Fix support for table aliases when checking for all primary keys in `UpdatableResultSet'. * Unpack `unknown' data types from server prepared statements as `Strings'. * Implemented `Statement.getWarnings()' for MySQL-4.1 and newer (using *Note `SHOW WARNINGS': show-warnings.). * Ensure that warnings are cleared before executing queries on prepared statements, as-per JDBC spec (now that we support warnings). * Correctly initialize datasource properties from JNDI Refs, including explicitly specified URLs. * Implemented long data (Blobs, Clobs, InputStreams, Readers) for server prepared statements. * Deal with 0-length tokens in `EscapeProcessor' (caused by callable statement escape syntax). * `DatabaseMetaData' now reports `supportsStoredProcedures()' for MySQL versions >= 5.0.0 * Support for *Note `mysql_change_user()': mysql-change-user. See the `changeUser()' method in `com.mysql.jdbc.Connection'. * Removed `useFastDates' connection property. * Support for NIO. Use `useNIO=true' on platforms that support NIO. * Check for closed connection on delete/update/insert row operations in `UpdatableResultSet'. * Support for transaction savepoints (MySQL >= 4.0.14 or 4.1.1). * Support `old' `profileSql' capitalization in `ConnectionProperties'. This property is deprecated, you should use `profileSQL' if possible. * Fixed character encoding issues when converting bytes to ASCII when MySQL doesn't provide the character set, and the JVM is set to a multi-byte encoding (usually affecting retrieval of numeric values). * Centralized setting of result set type and concurrency. * Fixed bug with `UpdatableResultSets' not using client-side prepared statements. * Default result set type changed to `TYPE_FORWARD_ONLY' (JDBC compliance). * Fixed `IllegalAccessError' to `Calendar.getTimeInMillis()' in `DateTimeValue' (for JDK < 1.4). * Allow contents of `PreparedStatement.setBlob()' to be retained between calls to `.execute*()'. * Fixed stack overflow in `Connection.prepareCall()' (bad merge). * Refactored how connection properties are set and exposed as `DriverPropertyInfo' as well as `Connection' and `DataSource' properties. * Reduced number of methods called in average query to be more efficient. * Prepared `Statements' will be re-prepared on auto-reconnect. Any errors encountered are postponed until first attempt to re-execute the re-prepared statement.  File: manual.info, Node: cj-news-3-1-0, Prev: cj-news-3-1-1, Up: cg-news-3-1 D.6.3.16 Changes in MySQL Connector/J 3.1.0 (18 February 2003 alpha) .................................................................... *Bugs fixed:* * Added `useServerPrepStmts' property (default `false'). The driver will use server-side prepared statements when the server version supports them (4.1 and newer) when this property is set to `true'. It is currently set to `false' by default until all bind/fetch functionality has been implemented. Currently only DML prepared statements are implemented for 4.1 server-side prepared statements. * Added `requireSSL' property. * Track open `Statements', close all when `Connection.close()' is called (JDBC compliance).  File: manual.info, Node: cg-news-3-0, Next: cj-news-2-0, Prev: cg-news-3-1, Up: cj-news D.6.4 Changes in MySQL Connector/J 3.0.x ---------------------------------------- * Menu: * cj-news-3-0-17:: Changes in MySQL Connector/J 3.0.17 (23 June 2005) * cj-news-3-0-16:: Changes in MySQL Connector/J 3.0.16 (15 November 2004) * cj-news-3-0-15:: Changes in MySQL Connector/J 3.0.15 (04 September 2004) * cj-news-3-0-14:: Changes in MySQL Connector/J 3.0.14 (28 May 2004) * cj-news-3-0-13:: Changes in MySQL Connector/J 3.0.13 (27 May 2004) * cj-news-3-0-12:: Changes in MySQL Connector/J 3.0.12 (18 May 2004) * cj-news-3-0-11:: Changes in MySQL Connector/J 3.0.11 (19 February 2004) * cj-news-3-0-10:: Changes in MySQL Connector/J 3.0.10 (13 January 2004) * cj-news-3-0-9:: Changes in MySQL Connector/J 3.0.9 (07 October 2003) * cj-news-3-0-8:: Changes in MySQL Connector/J 3.0.8 (23 May 2003) * cj-news-3-0-7:: Changes in MySQL Connector/J 3.0.7 (08 April 2003) * cj-news-3-0-6:: Changes in MySQL Connector/J 3.0.6 (18 February 2003) * cj-news-3-0-5:: Changes in MySQL Connector/J 3.0.5 (22 January 2003) * cj-news-3-0-4:: Changes in MySQL Connector/J 3.0.4 (06 January 2003) * cj-news-3-0-3:: Changes in MySQL Connector/J 3.0.3 (17 December 2002) * cj-news-3-0-2:: Changes in MySQL Connector/J 3.0.2 (08 November 2002) * cj-news-3-0-1:: Changes in MySQL Connector/J 3.0.1 (21 September 2002) * cj-news-3-0-0:: Changes in MySQL Connector/J 3.0.0 (31 July 2002)  File: manual.info, Node: cj-news-3-0-17, Next: cj-news-3-0-16, Prev: cg-news-3-0, Up: cg-news-3-0 D.6.4.1 Changes in MySQL Connector/J 3.0.17 (23 June 2005) .......................................................... *Bugs fixed:* * Workaround for server Bug#9098: Default values of `CURRENT_*' for *Note `DATE': datetime, *Note `TIME': time, *Note `DATETIME': datetime, and *Note `TIMESTAMP': datetime. columns can't be distinguished from `string' values, so `UpdatableResultSet.moveToInsertRow()' generates bad SQL for inserting default values. (Bug #8812) * `NON_UNIQUE' column from `DBMD.getIndexInfo()' returned inverted value. (Bug #8812) * `EUCKR' charset is sent as `SET NAMES euc_kr' which MySQL-4.1 and newer doesn't understand. (Bug #8629) * Added support for the `EUC_JP_Solaris' character encoding, which maps to a MySQL encoding of `eucjpms' (backported from 3.1 branch). This only works on servers that support `eucjpms', namely 5.0.3 or later. (Bug #8629) * Use hex escapes for `PreparedStatement.setBytes()' for double-byte charsets including `aliases' `Windows-31J', `CP934', `MS932'. (Bug #8629) * `DatabaseMetaData.supportsSelectForUpdate()' returns correct value based on server version. (Bug #8629) * Which requires hex escaping of binary data when using multi-byte charsets with prepared statements. (Bug #8064) * Fixed duplicated code in `configureClientCharset()' that prevented `useOldUTF8Behavior=true' from working properly. (Bug #7952) * Backported SQLState codes mapping from Connector/J 3.1, enable with `useSqlStateCodes=true' as a connection property, it defaults to `false' in this release, so that we don't break legacy applications (it defaults to `true' starting with Connector/J 3.1). (Bug #7686) * Timestamp key column data needed `_binary' stripped for `UpdatableResultSet.refreshRow()'. (Bug #7686) * `MS932', `SHIFT_JIS', and `Windows_31J' not recognized as aliases for `sjis'. (Bug #7607) * Handle streaming result sets with more than 2 billion rows properly by fixing wraparound of row number counter. (Bug #7601) * `PreparedStatement.fixDecimalExponent()' adding extra `+', making number unparseable by MySQL server. (Bug #7601) * Escape sequence {fn convert(..., type)} now supports ODBC-style types that are prepended by `SQL_'. (Bug #7601) * Statements created from a pooled connection were returning physical connection instead of logical connection when `getConnection()' was called. (Bug #7316) * Support new protocol type `MYSQL_TYPE_VARCHAR'. (Bug #7081) * Added `useOldUTF8Behavior'' configuration property, which causes JDBC driver to act like it did with MySQL-4.0.x and earlier when the character encoding is `utf-8' when connected to MySQL-4.1 or newer. (Bug #7081) * `DatabaseMetaData.getIndexInfo()' ignored `unique' parameter. (Bug #7081) * `PreparedStatement.fixDecimalExponent()' adding extra `+', making number unparseable by MySQL server. (Bug #7061) * `PreparedStatements' don't encode Big5 (and other multi-byte) character sets correctly in static SQL strings. (Bug #7033) * Connections starting up failed-over (due to down master) never retry master. (Bug #6966) * Adding `CP943' to aliases for `sjis'. (Bug #6549, Bug #7607) * `Timestamp'/`Time' conversion goes in the wrong `direction' when `useTimeZone=true' and server time zone differs from client time zone. (Bug #5874)  File: manual.info, Node: cj-news-3-0-16, Next: cj-news-3-0-15, Prev: cj-news-3-0-17, Up: cg-news-3-0 D.6.4.2 Changes in MySQL Connector/J 3.0.16 (15 November 2004) .............................................................. *Bugs fixed:* * Made `TINYINT(1)' -> *Note `BIT': numeric-types./`Boolean' conversion configurable using `tinyInt1isBit' property (default `true' to be JDBC compliant out of the box). (Bug #5664) * Off-by-one bug in `Buffer.readString(STRING)'. (Bug #5664) * `ResultSet.updateByte()' when on insert row throws `ArrayOutOfBoundsException'. (Bug #5664) * Fixed regression where `useUnbufferedInput' was defaulting to `false'. (Bug #5664) * `ResultSet.getTimestamp()' on a column with *Note `TIME': time. in it fails. (Bug #5664) * Fixed `DatabaseMetaData.getTypes()' returning incorrect (this is, nonnegative) scale for the *Note `NUMERIC': numeric-types. type. (Bug #5664) * Only set `character_set_results' during connection establishment if server version >= 4.1.1. (Bug #5664) * Fixed `ResultSetMetaData.isReadOnly()' to detect nonwritable columns when connected to MySQL-4.1 or newer, based on existence of `original' table and column names. * Re-issue character set configuration commands when re-using pooled connections or `Connection.changeUser()' when connected to MySQL-4.1 or newer.  File: manual.info, Node: cj-news-3-0-15, Next: cj-news-3-0-14, Prev: cj-news-3-0-16, Up: cg-news-3-0 D.6.4.3 Changes in MySQL Connector/J 3.0.15 (04 September 2004) ............................................................... *Bugs fixed:* * `ResultSet.getMetaData()' should not return incorrectly initialized metadata if the result set has been closed, but should instead throw an `SQLException'. Also fixed for `getRow()' and `getWarnings()' and traversal methods by calling `checkClosed()' before operating on instance-level fields that are nullified during `.close()'. (Bug #5069) * Use `_binary' introducer for `PreparedStatement.setBytes()' and `set*Stream()' when connected to MySQL-4.1.x or newer to avoid misinterpretation during character conversion. (Bug #5069) * Parse new time zone variables from 4.1.x servers. (Bug #5069) * `ResultSet' should release `Field[]' instance in `.close()'. (Bug #5022) * `RSMD.getPrecision()' returning 0 for nonnumeric types (should return max length in chars for nonbinary types, max length in bytes for binary types). This fix also fixes mapping of `RSMD.getColumnType()' and `RSMD.getColumnTypeName()' for the *Note `BLOB': blob. types based on the length sent from the server (the server doesn't distinguish between *Note `TINYBLOB': blob, *Note `BLOB': blob, *Note `MEDIUMBLOB': blob. or *Note `LONGBLOB': blob. at the network protocol level). (Bug #4880) * `Production' is now `GA' (General Availability) in naming scheme of distributions. (Bug #4860, Bug #4138) * `DBMD.getColumns()' returns incorrect JDBC type for unsigned columns. This affects type mappings for all numeric types in the `RSMD.getColumnType()' and `RSMD.getColumnTypeNames()' methods as well, to ensure that `like' types from `DBMD.getColumns()' match up with what `RSMD.getColumnType()' and `getColumnTypeNames()' return. (Bug #4860, Bug #4138) * Calling `.close()' twice on a `PooledConnection' causes NPE. (Bug #4808) * *Note `DOUBLE': numeric-types. mapped twice in `DBMD.getTypeInfo()'. (Bug #4742) * Added FLOSS license exemption. (Bug #4742) * Removed redundant calls to `checkRowPos()' in `ResultSet'. (Bug #4334) * Failover for `autoReconnect' not using port numbers for any hosts, and not retrying all hosts. *Warning*: This required a change to the `SocketFactory' `connect()' method signature, which is now `public Socket connect(String host, int portNumber, Properties props)'; therefore, any third-party socket factories will have to be changed to support this signature. (Bug #4334) * Logical connections created by `MysqlConnectionPoolDataSource' will now issue a `rollback()' when they are closed and sent back to the pool. If your application server/connection pool already does this for you, you can set the `rollbackOnPooledClose' property to `false' to avoid the overhead of an extra `rollback()'. (Bug #4334) * `StringUtils.escapeEasternUnicodeByteStream' was still broken for GBK. (Bug #4010)  File: manual.info, Node: cj-news-3-0-14, Next: cj-news-3-0-13, Prev: cj-news-3-0-15, Up: cg-news-3-0 D.6.4.4 Changes in MySQL Connector/J 3.0.14 (28 May 2004) ......................................................... *Bugs fixed:* * Fixed URL parsing error.  File: manual.info, Node: cj-news-3-0-13, Next: cj-news-3-0-12, Prev: cj-news-3-0-14, Up: cg-news-3-0 D.6.4.5 Changes in MySQL Connector/J 3.0.13 (27 May 2004) ......................................................... *Bugs fixed:* * `No Database Selected' when using `MysqlConnectionPoolDataSource'. (Bug #3920) * `PreparedStatement.getGeneratedKeys()' method returns only 1 result for batched insertions. (Bug #3873) * Using a `MySQLDatasource' without server name fails. (Bug #3848)  File: manual.info, Node: cj-news-3-0-12, Next: cj-news-3-0-11, Prev: cj-news-3-0-13, Up: cg-news-3-0 D.6.4.6 Changes in MySQL Connector/J 3.0.12 (18 May 2004) ......................................................... *Bugs fixed:* * Inconsistent reporting of data type. The server still doesn't return all types for *BLOBs *TEXT correctly, so the driver won't return those correctly. (Bug #3570) * `UpdatableResultSet' not picking up default values for `moveToInsertRow()'. (Bug #3557) * Not specifying database in URL caused `MalformedURL' exception. (Bug #3554) * Auto-convert MySQL encoding names to Java encoding names if used for `characterEncoding' property. (Bug #3554) * Use `junit.textui.TestRunner' for all unit tests (to enable them to be run from the command line outside of Ant or Eclipse). (Bug #3554) * Added encoding names that are recognized on some JVMs to fix case where they were reverse-mapped to MySQL encoding names incorrectly. (Bug #3554) * Made `StringRegressionTest' 4.1-unicode aware. (Bug #3520) * Fixed regression in `PreparedStatement.setString()' and eastern character encodings. (Bug #3520) * `DBMD.getSQLStateType()' returns incorrect value. (Bug #3520) * Renamed `StringUtils.escapeSJISByteStream()' to more appropriate `escapeEasternUnicodeByteStream()'. (Bug #3511) * `StringUtils.escapeSJISByteStream()' not covering all eastern double-byte charsets correctly. (Bug #3511) * Return creating statement for `ResultSets' created by `getGeneratedKeys()'. (Bug #2957) * Use `SET character_set_results' during initialization to enable any charset to be returned to the driver for result sets. (Bug #2670) * Don't truncate `BLOB' or `CLOB' values when using `setBytes()' and `setBinary/CharacterStream()'. (Bug #2670) * Dynamically configure character set mappings for field-level character sets on MySQL-4.1.0 and newer using *Note `SHOW COLLATION': show-collation. when connecting. (Bug #2670) * Map `binary' character set to `US-ASCII' to support *Note `DATETIME': datetime. charset recognition for servers >= 4.1.2. (Bug #2670) * Use `charsetnr' returned during connect to encode queries before issuing `SET NAMES' on MySQL >= 4.1.0. (Bug #2670) * Add helper methods to `ResultSetMetaData' (`getColumnCharacterEncoding()' and `getColumnCharacterSet()') to permit end users to see what charset the driver thinks it should be using for the column. (Bug #2670) * Only set `character_set_results' for MySQL >= 4.1.0. (Bug #2670) * Allow `url' parameter for `MysqlDataSource' and `MysqlConnectionPool' `DataSource' so that passing of other properties is possible from inside appservers. * Don't escape SJIS/GBK/BIG5 when using MySQL-4.1 or newer. * Backport documentation tooling from 3.1 branch. * Added `failOverReadOnly' property, to enable the user to configure the state of the connection (read-only/writable) when failed over. * Allow `java.util.Date' to be sent in as parameter to `PreparedStatement.setObject()', converting it to a `Timestamp' to maintain full precision. . (Bug #103) * Add unsigned attribute to `DatabaseMetaData.getColumns()' output in the `TYPE_NAME' column. * Map duplicate key and foreign key errors to SQLState of `23000'. * Backported `change user' and `reset server state' functionality from 3.1 branch, to enable clients of `MysqlConnectionPoolDataSource' to reset server state on `getConnection()' on a pooled connection.  File: manual.info, Node: cj-news-3-0-11, Next: cj-news-3-0-10, Prev: cj-news-3-0-12, Up: cg-news-3-0 D.6.4.7 Changes in MySQL Connector/J 3.0.11 (19 February 2004) .............................................................. *Bugs fixed:* * Return `java.lang.Double' for *Note `FLOAT': numeric-types. type from `ResultSetMetaData.getColumnClassName()'. (Bug #2855) * Return `[B' instead of `java.lang.Object' for *Note `BINARY': binary-varbinary, *Note `VARBINARY': binary-varbinary. and `LONGVARBINARY' types from `ResultSetMetaData.getColumnClassName()' (JDBC compliance). (Bug #2855) * Issue connection events on all instances created from a `ConnectionPoolDataSource'. (Bug #2855) * Return `java.lang.Integer' for *Note `TINYINT': numeric-types. and *Note `SMALLINT': numeric-types. types from `ResultSetMetaData.getColumnClassName()'. (Bug #2852) * Added `useUnbufferedInput' parameter, and now use it by default (due to JVM issue `http://developer.java.sun.com/developer/bugParade/bugs/4401235.html') (Bug #2578) * Fixed failover always going to last host in list. (Bug #2578) * Detect `on'/`off' or `1', `2', `3' form of `lower_case_table_names' value on server. (Bug #2578) * `AutoReconnect' time was growing faster than exponentially. (Bug #2447) * Trigger a `SET NAMES utf8' when encoding is forced to `utf8' _or_ `utf-8' using the `characterEncoding' property. Previously, only the Java-style encoding name of `utf-8' would trigger this.  File: manual.info, Node: cj-news-3-0-10, Next: cj-news-3-0-9, Prev: cj-news-3-0-11, Up: cg-news-3-0 D.6.4.8 Changes in MySQL Connector/J 3.0.10 (13 January 2004) ............................................................. *Bugs fixed:* * Enable caching of the parsing stage of prepared statements using the `cachePrepStmts', `prepStmtCacheSize', and `prepStmtCacheSqlLimit' properties (disabled by default). (Bug #2006) * Fixed security exception when used in Applets (applets can't read the system property `file.encoding' which is needed for *Note `LOAD DATA LOCAL INFILE': load-data.). (Bug #2006) * Speed up parsing of `PreparedStatements', try to use one-pass whenever possible. (Bug #2006) * Fixed exception `Unknown character set 'danish'' on connect with JDK-1.4.0 (Bug #2006) * Fixed mappings in SQLError to report deadlocks with SQLStates of `41000'. (Bug #2006) * Removed static synchronization bottleneck from instance factory method of `SingleByteCharsetConverter'. (Bug #2006) * Removed static synchronization bottleneck from `PreparedStatement.setTimestamp()'. (Bug #2006) * `ResultSet.findColumn()' should use first matching column name when there are duplicate column names in *Note `SELECT': select. query (JDBC-compliance). (Bug #2006) * `maxRows' property would affect internal statements, so check it for all statement creation internal to the driver, and set to 0 when it is not. (Bug #2006) * Use constants for SQLStates. (Bug #2006) * Map charset `ko18_ru' to `ko18r' when connected to MySQL-4.1.0 or newer. (Bug #2006) * Ensure that `Buffer.writeString()' saves room for the `\0'. (Bug #2006) * `ArrayIndexOutOfBounds' when parameter number == number of parameters + 1. (Bug #1958) * Connection property `maxRows' not honored. (Bug #1933) * Statements being created too many times in `DBMD.extractForeignKeyFromCreateTable()'. (Bug #1925) * Support escape sequence {fn convert ... }. (Bug #1914) * Implement `ResultSet.updateClob()'. (Bug #1913) * Autoreconnect code didn't set catalog upon reconnect if it had been changed. (Bug #1913) * `ResultSet.getObject()' on *Note `TINYINT': numeric-types. and *Note `SMALLINT': numeric-types. columns should return Java type `Integer'. (Bug #1913) * Added more descriptive error message `Server Configuration Denies Access to DataSource', as well as retrieval of message from server. (Bug #1913) * `ResultSetMetaData.isCaseSensitive()' returned wrong value for *Note `CHAR': char./*Note `VARCHAR': char. columns. (Bug #1913) * Added `alwaysClearStream' connection property, which causes the driver to always empty any remaining data on the input stream before each query. (Bug #1913) * `DatabaseMetaData.getSystemFunction()' returning bad function `VResultsSion'. (Bug #1775) * Foreign Keys column sequence is not consistent in `DatabaseMetaData.getImported/Exported/CrossReference()'. (Bug #1731) * Fix for `ArrayIndexOutOfBounds' exception when using `Statement.setMaxRows()'. (Bug #1695) * Subsequent call to `ResultSet.updateFoo()' causes NPE if result set is not updatable. (Bug #1630) * Fix for 4.1.1-style authentication with no password. (Bug #1630) * Cross-database updatable result sets are not checked for updatability correctly. (Bug #1592) * `DatabaseMetaData.getColumns()' should return `Types.LONGVARCHAR' for MySQL *Note `LONGTEXT': blob. type. (Bug #1592) * Fixed regression of `Statement.getGeneratedKeys()' and *Note `REPLACE': replace. statements. (Bug #1576) * Barge blobs and split packets not being read correctly. (Bug #1576) * Backported fix for aliased tables and `UpdatableResultSets' in `checkUpdatability()' method from 3.1 branch. (Bug #1534) * `Friendlier' exception message for `PacketTooLargeException'. (Bug #1534) * Don't count quoted IDs when inside a 'string' in `PreparedStatement' parsing. (Bug #1511)  File: manual.info, Node: cj-news-3-0-9, Next: cj-news-3-0-8, Prev: cj-news-3-0-10, Up: cg-news-3-0 D.6.4.9 Changes in MySQL Connector/J 3.0.9 (07 October 2003) ............................................................ *Bugs fixed:* * `ResultSet.get/setString' mashing char 127. (Bug #1247) * Added property to `clobber' streaming results, by setting the `clobberStreamingResults' property to `true' (the default is `false'). This will cause a `streaming' `ResultSet' to be automatically closed, and any outstanding data still streaming from the server to be discarded if another query is executed before all the data has been read from the server. (Bug #1247) * Added `com.mysql.jdbc.util.BaseBugReport' to help creation of testcases for bug reports. (Bug #1247) * Backported authentication changes for 4.1.1 and newer from 3.1 branch. (Bug #1247) * Made `databaseName', `portNumber', and `serverName' optional parameters for `MysqlDataSourceFactory'. (Bug #1246) * Optimized `CLOB.setChracterStream()'. (Bug #1131) * Fixed `CLOB.truncate()'. (Bug #1130) * Fixed deadlock issue with `Statement.setMaxRows()'. (Bug #1099) * `DatabaseMetaData.getColumns()' getting confused about the keyword `set' in character columns. (Bug #1099) * Clip +/- INF (to smallest and largest representative values for the type in MySQL) and NaN (to 0) for `setDouble'/`setFloat()', and issue a warning on the statement when the server does not support +/- INF or NaN. (Bug #884) * Don't fire connection closed events when closing pooled connections, or on `PooledConnection.getConnection()' with already open connections. (Bug #884) * Double-escaping of `'\'' when charset is SJIS or GBK and `'\'' appears in nonescaped input. (Bug #879) * When emptying input stream of unused rows for `streaming' result sets, have the current thread `yield()' every 100 rows to not monopolize CPU time. (Bug #879) * Issue exception on `ResultSet.getXXX()' on empty result set (wasn't caught in some cases). (Bug #848) * Don't hide messages from exceptions thrown in I/O layers. (Bug #848) * Fixed regression in large split-packet handling. (Bug #848) * Better diagnostic error messages in exceptions for `streaming' result sets. (Bug #848) * Don't change timestamp TZ twice if `useTimezone==true'. (Bug #774) * Don't wrap `SQLExceptions' in `RowDataDynamic'. (Bug #688) * Don't try and reset isolation level on reconnect if MySQL doesn't support them. (Bug #688) * The `insertRow' in an `UpdatableResultSet' is now loaded with the default column values when `moveToInsertRow()' is called. (Bug #688) * `DatabaseMetaData.getColumns()' wasn't returning `NULL' for default values that are specified as `NULL'. (Bug #688) * Change default statement type/concurrency to `TYPE_FORWARD_ONLY' and `CONCUR_READ_ONLY' (spec compliance). (Bug #688) * Fix `UpdatableResultSet' to return values for `getXXX()' when on insert row. (Bug #675) * Support `InnoDB' constraint names when extracting foreign key information in `DatabaseMetaData' (implementing ideas from Parwinder Sekhon). (Bug #664, Bug #517) * Backported 4.1 protocol changes from 3.1 branch (server-side SQL states, new field information, larger client capability flags, connect-with-database, and so forth). (Bug #664, Bug #517) * `refreshRow' didn't work when primary key values contained values that needed to be escaped (they ended up being doubly escaped). (Bug #661) * Fixed `ResultSet.previous()' behavior to move current position to before result set when on first row of result set. (Bug #496) * Fixed `Statement' and `PreparedStatement' issuing bogus queries when `setMaxRows()' had been used and a `LIMIT' clause was present in the query. (Bug #496) * Faster date handling code in `ResultSet' and `PreparedStatement' (no longer uses `Date' methods that synchronize on static calendars). * Fixed test for end of buffer in `Buffer.readString()'.  File: manual.info, Node: cj-news-3-0-8, Next: cj-news-3-0-7, Prev: cj-news-3-0-9, Up: cg-news-3-0 D.6.4.10 Changes in MySQL Connector/J 3.0.8 (23 May 2003) ......................................................... *Bugs fixed:* * Fixed SJIS encoding bug, thanks to Naoto Sato. (Bug #378) * Fix problem detecting server character set in some cases. (Bug #378) * Allow multiple calls to `Statement.close()'. (Bug #378) * Return correct number of generated keys when using *Note `REPLACE': replace. statements. (Bug #378) * Unicode character 0xFFFF in a string would cause the driver to throw an `ArrayOutOfBoundsException'. . (Bug #378) * Fix row data decoding error when using _very_ large packets. (Bug #378) * Optimized row data decoding. (Bug #378) * Issue exception when operating on an already closed prepared statement. (Bug #378) * Optimized usage of `EscapeProcessor'. (Bug #378) * Use JVM charset with file names and `LOAD DATA [LOCAL] INFILE'. * Fix infinite loop with `Connection.cleanup()'. * Changed Ant target `compile-core' to `compile-driver', and made testsuite compilation a separate target. * Fixed result set not getting set for `Statement.executeUpdate()', which affected `getGeneratedKeys()' and `getUpdateCount()' in some cases. * Return list of generated keys when using multi-value `INSERTS' with `Statement.getGeneratedKeys()'. * Allow bogus URLs in `Driver.getPropertyInfo()'.  File: manual.info, Node: cj-news-3-0-7, Next: cj-news-3-0-6, Prev: cj-news-3-0-8, Up: cg-news-3-0 D.6.4.11 Changes in MySQL Connector/J 3.0.7 (08 April 2003) ........................................................... *Bugs fixed:* * Fixed charset issues with database metadata (charset was not getting set correctly). * You can now toggle profiling on/off using `Connection.setProfileSql(boolean)'. * 4.1 Column Metadata fixes. * Fixed `MysqlPooledConnection.close()' calling wrong event type. * Fixed `StringIndexOutOfBoundsException' in `PreparedStatement.setClob()'. * `IOExceptions' during a transaction now cause the `Connection' to be closed. * Remove synchronization from `Driver.connect()' and `Driver.acceptsUrl()'. * Fixed missing conversion for *Note `YEAR': year. type in `ResultSetMetaData.getColumnTypeName()'. * Updatable `ResultSets' can now be created for aliased tables/columns when connected to MySQL-4.1 or newer. * Fixed *Note `LOAD DATA LOCAL INFILE': load-data. bug when file > `max_allowed_packet'. * Don't pick up indexes that start with `pri' as primary keys for `DBMD.getPrimaryKeys()'. * Ensure that packet size from `alignPacketSize()' does not exceed `max_allowed_packet' (JVM bug) * Don't reset `Connection.isReadOnly()' when autoReconnecting. * Fixed escaping of 0x5c (`'\'') character for GBK and Big5 charsets. * Fixed `ResultSet.getTimestamp()' when underlying field is of type *Note `DATE': datetime. * Throw `SQLExceptions' when trying to do operations on a forcefully closed `Connection' (that is, when a communication link failure occurs).  File: manual.info, Node: cj-news-3-0-6, Next: cj-news-3-0-5, Prev: cj-news-3-0-7, Up: cg-news-3-0 D.6.4.12 Changes in MySQL Connector/J 3.0.6 (18 February 2003) .............................................................. *Bugs fixed:* * Backported 4.1 charset field info changes from Connector/J 3.1. * Fixed `Statement.setMaxRows()' to stop sending `LIMIT' type queries when not needed (performance). * Fixed `DBMD.getTypeInfo()' and `DBMD.getColumns()' returning different value for precision in *Note `TEXT': blob. and *Note `BLOB': blob. types. * Fixed `SQLExceptions' getting swallowed on initial connect. * Fixed `ResultSetMetaData' to return `""' when catalog not known. Fixes `NullPointerExceptions' with Sun's `CachedRowSet'. * Allow ignoring of warning for `non transactional tables' during rollback (compliance/usability) by setting `ignoreNonTxTables' property to `true'. * Clean up `Statement' query/method mismatch tests (that is, *Note `INSERT': insert. not permitted with `.executeQuery()'). * Fixed `ResultSetMetaData.isWritable()' to return correct value. * More checks added in `ResultSet' traversal method to catch when in closed state. * Implemented `Blob.setBytes()'. You still need to pass the resultant `Blob' back into an updatable `ResultSet' or `PreparedStatement' to persist the changes, because MySQL does not support `locators'. * Add `window' of different `NULL' sorting behavior to `DBMD.nullsAreSortedAtStart' (4.0.2 to 4.0.10, true; otherwise, no).  File: manual.info, Node: cj-news-3-0-5, Next: cj-news-3-0-4, Prev: cj-news-3-0-6, Up: cg-news-3-0 D.6.4.13 Changes in MySQL Connector/J 3.0.5 (22 January 2003) ............................................................. *Bugs fixed:* * Fixed `ResultSet.isBeforeFirst()' for empty result sets. * Added missing *Note `LONGTEXT': blob. type to `DBMD.getColumns()'. * Implemented an empty `TypeMap' for `Connection.getTypeMap()' so that some third-party apps work with MySQL (IBM WebSphere 5.0 Connection pool). * Added update options for foreign key metadata. * Fixed `Buffer.fastSkipLenString()' causing `ArrayIndexOutOfBounds' exceptions with some queries when unpacking fields. * Quote table names in `DatabaseMetaData.getColumns()', `getPrimaryKeys()', `getIndexInfo()', `getBestRowIdentifier()'. * Retrieve `TX_ISOLATION' from database for `Connection.getTransactionIsolation()' when the MySQL version supports it, instead of an instance variable. * Greatly reduce memory required for `setBinaryStream()' in `PreparedStatements'.  File: manual.info, Node: cj-news-3-0-4, Next: cj-news-3-0-3, Prev: cj-news-3-0-5, Up: cg-news-3-0 D.6.4.14 Changes in MySQL Connector/J 3.0.4 (06 January 2003) ............................................................. *Bugs fixed:* * Streamlined character conversion and `byte[]' handling in `PreparedStatements' for `setByte()'. * Fixed `PreparedStatement.executeBatch()' parameter overwriting. * Added quoted identifiers to database names for `Connection.setCatalog'. * Added support for 4.0.8-style large packets. * Reduce memory footprint of `PreparedStatements' by sharing outbound packet with `MysqlIO'. * Added `strictUpdates' property to enable control of amount of checking for `correctness' of updatable result sets. Set this to `false' if you want faster updatable result sets and you know that you create them from *Note `SELECT': select. statements on tables with primary keys and that you have selected all primary keys in your query. * Added support for quoted identifiers in `PreparedStatement' parser.  File: manual.info, Node: cj-news-3-0-3, Next: cj-news-3-0-2, Prev: cj-news-3-0-4, Up: cg-news-3-0 D.6.4.15 Changes in MySQL Connector/J 3.0.3 (17 December 2002) .............................................................. *Bugs fixed:* * Allow user to alter behavior of `Statement'/ `PreparedStatement.executeBatch()' using `continueBatchOnError' property (defaults to `true'). * More robust escape tokenizer: Recognize `--' comments, and permit nested escape sequences (see `testsuite.EscapeProcessingTest'). * Fixed `Buffer.isLastDataPacket()' for 4.1 and newer servers. * `NamedPipeSocketFactory' now works (only intended for Windows), see `README' for instructions. * Changed `charsToByte' in `SingleByteCharConverter' to be nonstatic. * Use nonaliased table/column names and database names to fully qualify tables and columns in `UpdatableResultSet' (requires MySQL-4.1 or newer). * `LOAD DATA LOCAL INFILE ...' now works, if your server is configured to permit it. Can be turned off with the `allowLoadLocalInfile' property (see the `README'). * Implemented `Connection.nativeSQL()'. * Fixed `ResultSetMetaData.getColumnTypeName()' returning *Note `BLOB': blob. for *Note `TEXT': blob. and *Note `TEXT': blob. for *Note `BLOB': blob. types. * Fixed charset handling in `Fields.java'. * Because of above, implemented `ResultSetMetaData.isAutoIncrement()' to use `Field.isAutoIncrement()'. * Substitute `'?'' for unknown character conversions in single-byte character sets instead of `'\0''. * Added `CLIENT_LONG_FLAG' to be able to get more column flags (`isAutoIncrement()' being the most important). * Honor `lower_case_table_names' when enabled in the server when doing table name comparisons in `DatabaseMetaData' methods. * `DBMD.getImported/ExportedKeys()' now handles multiple foreign keys per table. * More robust implementation of updatable result sets. Checks that _all_ primary keys of the table have been selected. * Some MySQL-4.1 protocol support (extended field info from selects). * Check for connection closed in more `Connection' methods (`createStatement', `prepareStatement', `setTransactionIsolation', `setAutoCommit'). * Fixed `ResultSetMetaData.getPrecision()' returning incorrect values for some floating-point types. * Changed `SingleByteCharConverter' to use lazy initialization of each converter.  File: manual.info, Node: cj-news-3-0-2, Next: cj-news-3-0-1, Prev: cj-news-3-0-3, Up: cg-news-3-0 D.6.4.16 Changes in MySQL Connector/J 3.0.2 (08 November 2002) .............................................................. *Bugs fixed:* * Implemented `Clob.setString()'. * Added `com.mysql.jdbc.MiniAdmin' class, which enables you to send `shutdown' command to MySQL server. This is intended to be used when `embedding' Java and MySQL server together in an end-user application. * Added SSL support. See `README' for information on how to use it. * All `DBMD' result set columns describing schemas now return `NULL' to be more compliant with the behavior of other JDBC drivers for other database systems (MySQL does not support schemas). * Use *Note `SHOW CREATE TABLE': show-create-table. when possible for determining foreign key information for `DatabaseMetaData'. Also enables cascade options for *Note `DELETE': delete. information to be returned. * Implemented `Clob.setCharacterStream()'. * Failover and `autoReconnect' work only when the connection is in an `autoCommit(false)' state, to stay transaction-safe. * Fixed `DBMD.supportsResultSetConcurrency()' so that it returns `true' for `ResultSet.TYPE_SCROLL_INSENSITIVE' and `ResultSet.CONCUR_READ_ONLY' or `ResultSet.CONCUR_UPDATABLE'. * Implemented `Clob.setAsciiStream()'. * Removed duplicate code from `UpdatableResultSet' (it can be inherited from `ResultSet', the extra code for each method to handle updatability I thought might someday be necessary has not been needed). * Fixed `UnsupportedEncodingException' thrown when `forcing' a character encoding using properties. * Fixed incorrect conversion in `ResultSet.getLong()'. * Implemented `ResultSet.updateBlob()'. * Removed some not-needed temporary object creation by smarter use of `Strings' in `EscapeProcessor', `Connection' and `DatabaseMetaData' classes. * Escape `0x5c' character in strings for the SJIS charset. * `PreparedStatement' now honors stream lengths in setBinary/Ascii/Character Stream() unless you set the connection property `useStreamLengthsInPrepStmts' to `false'. * Fixed issue with updatable result sets and `PreparedStatements' not working. * Fixed start position off-by-1 error in `Clob.getSubString()'. * Added `connectTimeout' parameter that enables users of JDK-1.4 and newer to specify a maximum time to wait to establish a connection. * Fixed various non-ASCII character encoding issues. * Fixed `ResultSet.isLast()' for empty result sets (should return `false'). * Added driver property `useHostsInPrivileges'. Defaults to `true'. Affects whether or not `@hostname' will be used in `DBMD.getColumn/TablePrivileges'. * Fixed `ResultSet.setFetchDirection(FETCH_UNKNOWN)'. * Added `queriesBeforeRetryMaster' property that specifies how many queries to issue when failed over before attempting to reconnect to the master (defaults to 50). * Fixed issue when calling `Statement.setFetchSize()' when using arbitrary values. * Properly restore connection properties when autoReconnecting or failing-over, including `autoCommit' state, and isolation level. * Implemented `Clob.truncate()'.  File: manual.info, Node: cj-news-3-0-1, Next: cj-news-3-0-0, Prev: cj-news-3-0-2, Up: cg-news-3-0 D.6.4.17 Changes in MySQL Connector/J 3.0.1 (21 September 2002) ............................................................... *Bugs fixed:* * Charsets now automatically detected. Optimized code for single-byte character set conversion. * Fixed `ResultSetMetaData.isSigned()' for *Note `TINYINT': numeric-types. and *Note `BIGINT': numeric-types. * Fixed `RowDataStatic.getAt()' off-by-one bug. * Fixed `ResultSet.getRow()' off-by-one bug. * Massive code clean-up to follow Java coding conventions (the time had come). * Implemented `ResultSet.getCharacterStream()'. * Added limited `Clob' functionality (`ResultSet.getClob()', `PreparedStatement.setClob()', `PreparedStatement.setObject(Clob)'. * `Connection.isClosed()' no longer `pings' the server. * `Connection.close()' issues `rollback()' when `getAutoCommit()' is `false'. * Added `socketTimeout' parameter to URL. * Added `LOCAL TEMPORARY' to table types in `DatabaseMetaData.getTableTypes()'. * Added `paranoid' parameter, which sanitizes error messages by removing `sensitive' information from them (such as host names, ports, or user names), as well as clearing `sensitive' data structures when possible.  File: manual.info, Node: cj-news-3-0-0, Prev: cj-news-3-0-1, Up: cg-news-3-0 D.6.4.18 Changes in MySQL Connector/J 3.0.0 (31 July 2002) .......................................................... *Bugs fixed:* * General source-code cleanup. * The driver now only works with JDK-1.2 or newer. * Fix and sort primary key names in `DBMetaData' (SF bugs 582086 and 582086). * `ResultSet.getTimestamp()' now works for *Note `DATE': datetime. types (SF bug 559134). * Float types now reported as `java.sql.Types.FLOAT' (SF bug 579573). * Support for streaming (row-by-row) result sets (see `README') Thanks to Doron. * Testsuite now uses Junit (which you can get from `http://www.junit.org'. * JDBC Compliance: Passes all tests besides stored procedure tests. * `ResultSet.getDate/Time/Timestamp' now recognizes all forms of invalid values that have been set to all zeros by MySQL (SF bug 586058). * Added multi-host failover support (see `README'). * Repackaging: New driver name is `com.mysql.jdbc.Driver', old name still works, though (the driver is now provided by MySQL-AB). * Support for large packets (new addition to MySQL-4.0 protocol), see `README' for more information. * Better checking for closed connections in `Statement' and `PreparedStatement'. * Performance improvements in string handling and field metadata creation (lazily instantiated) contributed by Alex Twisleton-Wykeham-Fiennes. * JDBC-3.0 functionality including `Statement/PreparedStatement.getGeneratedKeys()' and `ResultSet.getURL()'. * Overall speed improvements using controlling transient object creation in `MysqlIO' class when reading packets. * *!!! LICENSE CHANGE !!!* The driver is now GPL. If you need non-GPL licenses, please contact me `'. * Performance enhancements: Driver is now 50-100% faster in most situations, and creates fewer temporary objects.  File: manual.info, Node: cj-news-2-0, Next: cj-news-1-2b, Prev: cg-news-3-0, Up: cj-news D.6.5 Changes in MySQL Connector/J 2.0.x ---------------------------------------- * Menu: * cj-news-2-0-14:: Changes in MySQL Connector/J 2.0.14 (16 May 2002) * cj-news-2-0-13:: Changes in MySQL Connector/J 2.0.13 (24 April 2002) * cj-news-2-0-12:: Changes in MySQL Connector/J 2.0.12 (07 April 2002) * cj-news-2-0-11:: Changes in MySQL Connector/J 2.0.11 (27 January 2002) * cj-news-2-0-10:: Changes in MySQL Connector/J 2.0.10 (24 January 2002) * cj-news-2-0-9:: Changes in MySQL Connector/J 2.0.9 (13 January 2002) * cj-news-2-0-8:: Changes in MySQL Connector/J 2.0.8 (25 November 2001) * cj-news-2-0-7:: Changes in MySQL Connector/J 2.0.7 (24 October 2001) * cj-news-2-0-6:: Changes in MySQL Connector/J 2.0.6 (16 June 2001) * cj-news-2-0-5:: Changes in MySQL Connector/J 2.0.5 (13 June 2001) * cj-news-2-0-3:: Changes in MySQL Connector/J 2.0.3 (03 December 2000) * cj-news-2-0-1:: Changes in MySQL Connector/J 2.0.1 (06 April 2000) * cj-news-2-0pre5:: Changes in MySQL Connector/J 2.0.0pre5 (21 February 2000) * cj-news-2-0pre4:: Changes in MySQL Connector/J 2.0.0pre4 (10 January 2000) * cj-news-2-0pre:: Changes in MySQL Connector/J 2.0.0pre (17 August 1999)  File: manual.info, Node: cj-news-2-0-14, Next: cj-news-2-0-13, Prev: cj-news-2-0, Up: cj-news-2-0 D.6.5.1 Changes in MySQL Connector/J 2.0.14 (16 May 2002) ......................................................... *Bugs fixed:* * `ResultSet.getDouble()' now uses code built into JDK to be more precise (but slower). * Fixed typo for `relaxAutoCommit' parameter. * `LogicalHandle.isClosed()' calls through to physical connection. * Added SQL profiling (to `STDERR'). Set `profileSql=true' in your JDBC URL. See `README' for more information. * `PreparedStatement' now releases resources on `.close()'. (SF bug 553268) * More code cleanup. * Quoted identifiers not used if server version does not support them. Also, if server started with `--ansi' or `--sql-mode=ANSI_QUOTES', ``"'' will be used as an identifier quote character, otherwise ``''' will be used.  File: manual.info, Node: cj-news-2-0-13, Next: cj-news-2-0-12, Prev: cj-news-2-0-14, Up: cj-news-2-0 D.6.5.2 Changes in MySQL Connector/J 2.0.13 (24 April 2002) ........................................................... *Bugs fixed:* * Fixed unicode chars being read incorrectly. (SF bug 541088) * Faster blob escaping for `PrepStmt'. * Added `setURL()' to `MySQLXADataSource'. (SF bug 546019) * Added `set'/`getPortNumber()' to `DataSource(s)'. (SF bug 548167) * `PreparedStatement.toString()' fixed. (SF bug 534026) * More code cleanup. * Rudimentary version of `Statement.getGeneratedKeys()' from JDBC-3.0 now implemented (you need to be using JDK-1.4 for this to work, I believe). * `DBMetaData.getIndexInfo()' - bad PAGES fixed. (SF BUG 542201) * `ResultSetMetaData.getColumnClassName()' now implemented.  File: manual.info, Node: cj-news-2-0-12, Next: cj-news-2-0-11, Prev: cj-news-2-0-13, Up: cj-news-2-0 D.6.5.3 Changes in MySQL Connector/J 2.0.12 (07 April 2002) ........................................................... *Bugs fixed:* * Fixed `testsuite.Traversal' `afterLast()' bug, thanks to Igor Lastric. * Added new types to `getTypeInfo()', fixed existing types thanks to Al Davis and Kid Kalanon. * Fixed time zone off-by-1-hour bug in `PreparedStatement' (538286, 528785). * Added identifier quoting to all `DatabaseMetaData' methods that need them (should fix 518108). * Added support for *Note `BIT': numeric-types. types (51870) to `PreparedStatement'. * `ResultSet.insertRow()' should now detect auto_increment fields in most cases and use that value in the new row. This detection will not work in multi-valued keys, however, due to the fact that the MySQL protocol does not return this information. * Relaxed synchronization in all classes, should fix 520615 and 520393. * `DataSources' - fixed `setUrl' bug (511614, 525565), wrong datasource class name (532816, 528767). * Added support for *Note `YEAR': year. type (533556). * Fixes for `ResultSet' updatability in `PreparedStatement'. * `ResultSet': Fixed updatability (values being set to `null' if not updated). * Added `getTable/ColumnPrivileges()' to DBMD (fixes 484502). * Added `getIdleFor()' method to `Connection' and `MysqlLogicalHandle'. * `ResultSet.refreshRow()' implemented. * Fixed `getRow()' bug (527165) in `ResultSet'. * General code cleanup.  File: manual.info, Node: cj-news-2-0-11, Next: cj-news-2-0-10, Prev: cj-news-2-0-12, Up: cj-news-2-0 D.6.5.4 Changes in MySQL Connector/J 2.0.11 (27 January 2002) ............................................................. *Bugs fixed:* * Full synchronization of `Statement.java'. * Fixed missing `DELETE_RULE' value in `DBMD.getImported/ExportedKeys()' and `getCrossReference()'. * More changes to fix `Unexpected end of input stream' errors when reading *Note `BLOB': blob. values. This should be the last fix.  File: manual.info, Node: cj-news-2-0-10, Next: cj-news-2-0-9, Prev: cj-news-2-0-11, Up: cj-news-2-0 D.6.5.5 Changes in MySQL Connector/J 2.0.10 (24 January 2002) ............................................................. *Bugs fixed:* * Fixed null-pointer-exceptions when using `MysqlConnectionPoolDataSource' with Websphere 4 (bug 505839). * Fixed spurious `Unexpected end of input stream' errors in `MysqlIO' (bug 507456).  File: manual.info, Node: cj-news-2-0-9, Next: cj-news-2-0-8, Prev: cj-news-2-0-10, Up: cj-news-2-0 D.6.5.6 Changes in MySQL Connector/J 2.0.9 (13 January 2002) ............................................................ *Bugs fixed:* * Fixed extra memory allocation in `MysqlIO.readPacket()' (bug 488663). * Added detection of network connection being closed when reading packets (thanks to Todd Lizambri). * Fixed casting bug in `PreparedStatement' (bug 488663). * `DataSource' implementations moved to `org.gjt.mm.mysql.jdbc2.optional' package, and (initial) implementations of `PooledConnectionDataSource' and `XADataSource' are in place (thanks to Todd Wolff for the implementation and testing of `PooledConnectionDataSource' with IBM WebSphere 4). * Fixed quoting error with escape processor (bug 486265). * Removed concatenation support from driver (the `||' operator), as older versions of VisualAge seem to be the only thing that use it, and it conflicts with the logical `||' operator. You will need to start *Note `mysqld': mysqld. with the `--ansi' flag to use the `||' operator as concatenation (bug 491680). * `Ant' build was corrupting included `jar' files, fixed (bug 487669). * Report batch update support through `DatabaseMetaData' (bug 495101). * Implementation of `DatabaseMetaData.getExported/ImportedKeys()' and `getCrossReference()'. * Fixed off-by-one-hour error in `PreparedStatement.setTimestamp()' (bug 491577). * Full synchronization on methods modifying instance and class-shared references, driver should be entirely thread-safe now (please let me know if you have problems).  File: manual.info, Node: cj-news-2-0-8, Next: cj-news-2-0-7, Prev: cj-news-2-0-9, Up: cj-news-2-0 D.6.5.7 Changes in MySQL Connector/J 2.0.8 (25 November 2001) ............................................................. *Bugs fixed:* * `XADataSource'/`ConnectionPoolDataSource' code (experimental) * `DatabaseMetaData.getPrimaryKeys()' and `getBestRowIdentifier()' are now more robust in identifying primary keys (matches regardless of case or abbreviation/full spelling of `Primary Key' in `Key_type' column). * Batch updates now supported (thanks to some inspiration from Daniel Rall). * `PreparedStatement.setAnyNumericType()' now handles positive exponents correctly (adds `+' so MySQL can understand it).  File: manual.info, Node: cj-news-2-0-7, Next: cj-news-2-0-6, Prev: cj-news-2-0-8, Up: cj-news-2-0 D.6.5.8 Changes in MySQL Connector/J 2.0.7 (24 October 2001) ............................................................ *Bugs fixed:* * Character sets read from database if `useUnicode=true' and `characterEncoding' is not set. (thanks to Dmitry Vereshchagin) * Initial transaction isolation level read from database (if available). (thanks to Dmitry Vereshchagin) * Fixed `PreparedStatement' generating SQL that would end up with syntax errors for some queries. * `PreparedStatement.setCharacterStream()' now implemented * Captialize type names when `captializeTypeNames=true' is passed in URL or properties (for WebObjects. (thanks to Anjo Krank) * `ResultSet.getBlob()' now returns `null' if column value was `null'. * Fixed `ResultSetMetaData.getPrecision()' returning one less than actual on newer versions of MySQL. * Fixed dangling socket problem when in high availability (`autoReconnect=true') mode, and finalizer for `Connection' will close any dangling sockets on GC. * Fixed time zone issue in `PreparedStatement.setTimestamp()'. (thanks to Erik Olofsson) * PreparedStatement.setDouble() now uses full-precision doubles (reverting a fix made earlier to truncate them). * Fixed `DatabaseMetaData.supportsTransactions()', and `supportsTransactionIsolationLevel()' and `getTypeInfo()' `SQL_DATETIME_SUB' and `SQL_DATA_TYPE' fields not being readable. * Updatable result sets now correctly handle `NULL' values in fields. * PreparedStatement.setBoolean() will use 1/0 for values if your MySQL version is 3.21.23 or higher. * Fixed `ResultSet.isAfterLast()' always returning `false'.  File: manual.info, Node: cj-news-2-0-6, Next: cj-news-2-0-5, Prev: cj-news-2-0-7, Up: cj-news-2-0 D.6.5.9 Changes in MySQL Connector/J 2.0.6 (16 June 2001) ......................................................... *Bugs fixed:* * Fixed `PreparedStatement' parameter checking. * Fixed case-sensitive column names in `ResultSet.java'.  File: manual.info, Node: cj-news-2-0-5, Next: cj-news-2-0-3, Prev: cj-news-2-0-6, Up: cj-news-2-0 D.6.5.10 Changes in MySQL Connector/J 2.0.5 (13 June 2001) .......................................................... *Bugs fixed:* * `ResultSet.insertRow()' works now, even if not all columns are set (they will be set to `NULL'). * Added `Byte' to `PreparedStatement.setObject()'. * Fixed data parsing of *Note `TIMESTAMP': datetime. values with 2-digit years. * Added `ISOLATION' level support to `Connection.setIsolationLevel()' * `DataBaseMetaData.getCrossReference()' no longer `ArrayIndexOOB'. * `ResultSet.getBoolean()' now recognizes `-1' as `true'. * `ResultSet' has +/-Inf/inf support. * `getObject()' on `ResultSet' correctly does *Note `TINYINT': numeric-types.->`Byte' and *Note `SMALLINT': numeric-types.->`Short'. * Fixed `ResultSetMetaData.getColumnTypeName' for *Note `TEXT': blob./*Note `BLOB': blob. * Fixed `ArrayIndexOutOfBounds' when sending large *Note `BLOB': blob. queries. (Max size packet was not being set) * Fixed NPE on `PreparedStatement.executeUpdate()' when all columns have not been set. * Fixed `ResultSet.getBlob()' `ArrayIndex' out-of-bounds.  File: manual.info, Node: cj-news-2-0-3, Next: cj-news-2-0-1, Prev: cj-news-2-0-5, Up: cj-news-2-0 D.6.5.11 Changes in MySQL Connector/J 2.0.3 (03 December 2000) .............................................................. *Bugs fixed:* * Fixed composite key problem with updatable result sets. * Faster ASCII string operations. * Fixed off-by-one error in `java.sql.Blob' implementation code. * Fixed incorrect detection of `MAX_ALLOWED_PACKET', so sending large blobs should work now. * Added detection of -/+INF for doubles. * Added `ultraDevHack' URL parameter, set to `true' to enable (broken) Macromedia UltraDev to use the driver. * Implemented `getBigDecimal()' without scale component for JDBC2.  File: manual.info, Node: cj-news-2-0-1, Next: cj-news-2-0pre5, Prev: cj-news-2-0-3, Up: cj-news-2-0 D.6.5.12 Changes in MySQL Connector/J 2.0.1 (06 April 2000) ........................................................... *Bugs fixed:* * Columns that are of type *Note `TEXT': blob. now return as `Strings' when you use `getObject()'. * Cleaned up exception handling when driver connects. * Fixed `RSMD.isWritable()' returning wrong value. Thanks to Moritz Maass. * `DatabaseMetaData.getPrimaryKeys()' now works correctly with respect to `key_seq'. Thanks to Brian Slesinsky. * Fixed many JDBC-2.0 traversal, positioning bugs, especially with respect to empty result sets. Thanks to Ron Smits, Nick Brook, Cessar Garcia and Carlos Martinez. * No escape processing is done on `PreparedStatements' anymore per JDBC spec. * Fixed some issues with updatability support in `ResultSet' when using multiple primary keys.  File: manual.info, Node: cj-news-2-0pre5, Next: cj-news-2-0pre4, Prev: cj-news-2-0-1, Up: cj-news-2-0 D.6.5.13 Changes in MySQL Connector/J 2.0.0pre5 (21 February 2000) .................................................................. * Fixed Bad Handshake problem.  File: manual.info, Node: cj-news-2-0pre4, Next: cj-news-2-0pre, Prev: cj-news-2-0pre5, Up: cj-news-2-0 D.6.5.14 Changes in MySQL Connector/J 2.0.0pre4 (10 January 2000) ................................................................. * Fixes to ResultSet for insertRow() - Thanks to Cesar Garcia * Fix to Driver to recognize JDBC-2.0 by loading a JDBC-2.0 class, instead of relying on JDK version numbers. Thanks to John Baker. * Fixed ResultSet to return correct row numbers * Statement.getUpdateCount() now returns rows matched, instead of rows actually updated, which is more SQL-92 like. 10-29-99 * Statement/PreparedStatement.getMoreResults() bug fixed. Thanks to Noel J. Bergman. * Added Short as a type to PreparedStatement.setObject(). Thanks to Jeff Crowder * Driver now automagically configures maximum/preferred packet sizes by querying server. * Autoreconnect code uses fast ping command if server supports it. * Fixed various bugs with respect to packet sizing when reading from the server and when alloc'ing to write to the server.  File: manual.info, Node: cj-news-2-0pre, Prev: cj-news-2-0pre4, Up: cj-news-2-0 D.6.5.15 Changes in MySQL Connector/J 2.0.0pre (17 August 1999) ............................................................... * Now compiles under JDK-1.2. The driver supports both JDK-1.1 and JDK-1.2 at the same time through a core set of classes. The driver will load the appropriate interface classes at runtime by figuring out which JVM version you are using. * Fixes for result sets with all nulls in the first row. (Pointed out by Tim Endres) * Fixes to column numbers in SQLExceptions in ResultSet (Thanks to Blas Rodriguez Somoza) * The database no longer needs to specified to connect. (Thanks to Christian Motschke)  File: manual.info, Node: cj-news-1-2b, Next: cg-news-1-0, Prev: cj-news-2-0, Up: cj-news D.6.6 Changes in MySQL Connector/J 1.2b (04 July 1999) ------------------------------------------------------ * Better Documentation (in progress), in doc/mm.doc/book1.html * DBMD now permits null for a column name pattern (not in spec), which it changes to '%'. * DBMD now has correct types/lengths for getXXX(). * ResultSet.getDate(), getTime(), and getTimestamp() fixes. (contributed by Alan Wilken) * EscapeProcessor now handles \{ \} and { or } inside quotation marks correctly. (thanks to Alik for some ideas on how to fix it) * Fixes to properties handling in Connection. (contributed by Juho Tikkala) * ResultSet.getObject() now returns null for NULL columns in the table, rather than bombing out. (thanks to Ben Grosman) * ResultSet.getObject() now returns Strings for types from MySQL that it doesn't know about. (Suggested by Chris Perdue) * Removed DataInput/Output streams, not needed, 1/2 number of method calls per IO operation. * Use default character encoding if one is not specified. This is a work-around for broken JVMs, because according to spec, EVERY JVM must support "ISO8859_1", but they do not. * Fixed Connection to use the platform character encoding instead of "ISO8859_1" if one isn't explicitly set. This fixes problems people were having loading the character- converter classes that didn't always exist (JVM bug). (thanks to Fritz Elfert for pointing out this problem) * Changed MysqlIO to re-use packets where possible to reduce memory usage. * Fixed escape-processor bugs pertaining to {} inside quotation marks.  File: manual.info, Node: cg-news-1-0, Prev: cj-news-1-2b, Up: cj-news D.6.7 Changes in MySQL Connector/J 1.2.x and lower -------------------------------------------------- * Menu: * cj-news-1-2a:: Changes in MySQL Connector/J 1.2a (14 April 1999) * cj-news-1-1i:: Changes in MySQL Connector/J 1.1i (24 March 1999) * cj-news-1-1h:: Changes in MySQL Connector/J 1.1h (08 March 1999) * cj-news-1-1g:: Changes in MySQL Connector/J 1.1g (19 February 1999) * cj-news-1-1f:: Changes in MySQL Connector/J 1.1f (31 December 1998) * cj-news-1-1b:: Changes in MySQL Connector/J 1.1b (03 November 1998) * cj-news-1-1:: Changes in MySQL Connector/J 1.1 (02 September 1998) * cj-news-1-0:: Changes in MySQL Connector/J 1.0 (24 August 1998) * cj-news-0-9d:: Changes in MySQL Connector/J 0.9d (04 August 1998) * cj-news-0-9:: Changes in MySQL Connector/J 0.9 (28 July 1998) * cj-news-0-8:: Changes in MySQL Connector/J 0.8 (06 July 1998) * cj-news-0-7:: Changes in MySQL Connector/J 0.7 (01 July 1998) * cj-news-0-6:: Changes in MySQL Connector/J 0.6 (21 May 1998)  File: manual.info, Node: cj-news-1-2a, Next: cj-news-1-1i, Prev: cg-news-1-0, Up: cg-news-1-0 D.6.7.1 Changes in MySQL Connector/J 1.2a (14 April 1999) ......................................................... * Fixed character-set support for non-Javasoft JVMs (thanks to many people for pointing it out) * Fixed ResultSet.getBoolean() to recognize 'y' & 'n' as well as '1' & '0' as boolean flags. (thanks to Tim Pizey) * Fixed ResultSet.getTimestamp() to give better performance. (thanks to Richard Swift) * Fixed getByte() for numeric types. (thanks to Ray Bellis) * Fixed DatabaseMetaData.getTypeInfo() for DATE type. (thanks to Paul Johnston) * Fixed EscapeProcessor for "fn" calls. (thanks to Piyush Shah at locomotive.org) * Fixed EscapeProcessor to not do extraneous work if there are no escape codes. (thanks to Ryan Gustafson) * Fixed Driver to parse URLs of the form "jdbc:mysql://host:port" (thanks to Richard Lobb)  File: manual.info, Node: cj-news-1-1i, Next: cj-news-1-1h, Prev: cj-news-1-2a, Up: cg-news-1-0 D.6.7.2 Changes in MySQL Connector/J 1.1i (24 March 1999) ......................................................... * Fixed Timestamps for PreparedStatements * Fixed null pointer exceptions in RSMD and RS * Re-compiled with jikes for valid class files (thanks ms!)  File: manual.info, Node: cj-news-1-1h, Next: cj-news-1-1g, Prev: cj-news-1-1i, Up: cg-news-1-0 D.6.7.3 Changes in MySQL Connector/J 1.1h (08 March 1999) ......................................................... * Fixed escape processor to deal with unmatched { and } (thanks to Craig Coles) * Fixed escape processor to create more portable (between DATETIME and TIMESTAMP types) representations so that it will work with BETWEEN clauses. (thanks to Craig Longman) * MysqlIO.quit() now closes the socket connection. Before, after many failed connections some OS's would run out of file descriptors. (thanks to Michael Brinkman) * Fixed NullPointerException in Driver.getPropertyInfo. (thanks to Dave Potts) * Fixes to MysqlDefs to allow all *text fields to be retrieved as Strings. (thanks to Chris at Leverage) * Fixed setDouble in PreparedStatement for large numbers to avoid sending scientific notation to the database. (thanks to J.S. Ferguson) * Fixed getScale() and getPrecision() in RSMD. (contrib'd by James Klicman) * Fixed getObject() when field was DECIMAL or NUMERIC (thanks to Bert Hobbs) * DBMD.getTables() bombed when passed a null table-name pattern. Fixed. (thanks to Richard Lobb) * Added check for "client not authorized" errors during connect. (thanks to Hannes Wallnoefer)  File: manual.info, Node: cj-news-1-1g, Next: cj-news-1-1f, Prev: cj-news-1-1h, Up: cg-news-1-0 D.6.7.4 Changes in MySQL Connector/J 1.1g (19 February 1999) ............................................................ * Result set rows are now byte arrays. Blobs and Unicode work bidriectonally now. The useUnicode and encoding options are implemented now. * Fixes to PreparedStatement to send binary set by setXXXStream to be sent untouched to the MySQL server. * Fixes to getDriverPropertyInfo().  File: manual.info, Node: cj-news-1-1f, Next: cj-news-1-1b, Prev: cj-news-1-1g, Up: cg-news-1-0 D.6.7.5 Changes in MySQL Connector/J 1.1f (31 December 1998) ............................................................ * Changed all ResultSet fields to Strings, this should allow Unicode to work, but your JVM must be able to convert between the character sets. This should also make reading data from the server be a bit quicker, because there is now no conversion from StringBuffer to String. * Changed PreparedStatement.streamToString() to be more efficient (code from Uwe Schaefer). * URL parsing is more robust (throws SQL exceptions on errors rather than NullPointerExceptions) * PreparedStatement now can convert Strings to Time/Date values using setObject() (code from Robert Currey). * IO no longer hangs in Buffer.readInt(), that bug was introduced in 1.1d when changing to all byte-arrays for result sets. (Pointed out by Samo Login)  File: manual.info, Node: cj-news-1-1b, Next: cj-news-1-1, Prev: cj-news-1-1f, Up: cg-news-1-0 D.6.7.6 Changes in MySQL Connector/J 1.1b (03 November 1998) ............................................................ * Fixes to DatabaseMetaData to allow both IBM VA and J-Builder to work. Let me know how it goes. (thanks to Jac Kersing) * Fix to ResultSet.getBoolean() for NULL strings (thanks to Barry Lagerweij) * Beginning of code cleanup, and formatting. Getting ready to branch this off to a parallel JDBC-2.0 source tree. * Added "final" modifier to critical sections in MysqlIO and Buffer to allow compiler to inline methods for speed. 9-29-98 * If object references passed to setXXX() in PreparedStatement are null, setNull() is automatically called for you. (Thanks for the suggestion goes to Erik Ostrom) * setObject() in PreparedStatement will now attempt to write a serialized representation of the object to the database for objects of Types.OTHER and objects of unknown type. * Util now has a static method readObject() which given a ResultSet and a column index will re-instantiate an object serialized in the above manner.  File: manual.info, Node: cj-news-1-1, Next: cj-news-1-0, Prev: cj-news-1-1b, Up: cg-news-1-0 D.6.7.7 Changes in MySQL Connector/J 1.1 (02 September 1998) ............................................................ * Got rid of "ugly hack" in MysqlIO.nextRow(). Rather than catch an exception, Buffer.isLastDataPacket() was fixed. * Connection.getCatalog() and Connection.setCatalog() should work now. * Statement.setMaxRows() works, as well as setting by property maxRows. Statement.setMaxRows() overrides maxRows set using properties or url parameters. * Automatic re-connection is available. Because it has to "ping" the database before each query, it is turned off by default. To use it, pass in "autoReconnect=true" in the connection URL. You may also change the number of reconnect tries, and the initial timeout value using "maxReconnects=n" (default 3) and "initialTimeout=n" (seconds, default 2) parameters. The timeout is an exponential backoff type of timeout; for example, if you have initial timeout of 2 seconds, and maxReconnects of 3, then the driver will timeout 2 seconds, 4 seconds, then 16 seconds between each re-connection attempt.  File: manual.info, Node: cj-news-1-0, Next: cj-news-0-9d, Prev: cj-news-1-1, Up: cg-news-1-0 D.6.7.8 Changes in MySQL Connector/J 1.0 (24 August 1998) ......................................................... * Fixed handling of blob data in Buffer.java * Fixed bug with authentication packet being sized too small. * The JDBC Driver is now under the LGPL 8-14-98 * Fixed Buffer.readLenString() to correctly read data for BLOBS. * Fixed PreparedStatement.stringToStream to correctly read data for BLOBS. * Fixed PreparedStatement.setDate() to not add a day. (above fixes thanks to Vincent Partington) * Added URL parameter parsing (?user=... and so forth).  File: manual.info, Node: cj-news-0-9d, Next: cj-news-0-9, Prev: cj-news-1-0, Up: cg-news-1-0 D.6.7.9 Changes in MySQL Connector/J 0.9d (04 August 1998) .......................................................... * Big news! New package name. Tim Endres from ICE Engineering is starting a new source tree for GNU GPL'd Java software. He's graciously given me the org.gjt.mm package directory to use, so now the driver is in the org.gjt.mm.mysql package scheme. I'm "legal" now. Look for more information on Tim's project soon. * Now using dynamically sized packets to reduce memory usage when sending commands to the DB. * Small fixes to getTypeInfo() for parameters, and so forth. * DatabaseMetaData is now fully implemented. Let me know if these drivers work with the various IDEs out there. I've heard that they're working with JBuilder right now. * Added JavaDoc documentation to the package. * Package now available in .zip or .tar.gz.  File: manual.info, Node: cj-news-0-9, Next: cj-news-0-8, Prev: cj-news-0-9d, Up: cg-news-1-0 D.6.7.10 Changes in MySQL Connector/J 0.9 (28 July 1998) ........................................................ * Implemented getTypeInfo(). Connection.rollback() now throws an SQLException per the JDBC spec. * Added PreparedStatement that supports all JDBC API methods for PreparedStatement including InputStreams. Please check this out and let me know if anything is broken. * Fixed a bug in ResultSet that would break some queries that only returned 1 row. * Fixed bugs in DatabaseMetaData.getTables(), DatabaseMetaData.getColumns() and DatabaseMetaData.getCatalogs(). * Added functionality to Statement that enables executeUpdate() to store values for IDs that are automatically generated for AUTO_INCREMENT fields. Basically, after an executeUpdate(), look at the SQLWarnings for warnings like "LAST_INSERTED_ID = 'some number', COMMAND = 'your SQL query'". If you are using AUTO_INCREMENT fields in your tables and are executing a lot of executeUpdate()s on one Statement, be sure to clearWarnings() every so often to save memory.  File: manual.info, Node: cj-news-0-8, Next: cj-news-0-7, Prev: cj-news-0-9, Up: cg-news-1-0 D.6.7.11 Changes in MySQL Connector/J 0.8 (06 July 1998) ........................................................ * Split MysqlIO and Buffer to separate classes. Some ClassLoaders gave an IllegalAccess error for some fields in those two classes. Now mm.mysql works in applets and all classloaders. Thanks to Joe Ennis for pointing out the problem and working on a fix with me.  File: manual.info, Node: cj-news-0-7, Next: cj-news-0-6, Prev: cj-news-0-8, Up: cg-news-1-0 D.6.7.12 Changes in MySQL Connector/J 0.7 (01 July 1998) ........................................................ * Fixed DatabaseMetadata problems in getColumns() and bug in switch statement in the Field constructor. Thanks to Costin Manolache for pointing these out.  File: manual.info, Node: cj-news-0-6, Prev: cj-news-0-7, Up: cg-news-1-0 D.6.7.13 Changes in MySQL Connector/J 0.6 (21 May 1998) ....................................................... * Incorporated efficiency changes from Richard Swift in `MysqlIO.java' and `ResultSet.java': * We're now 15% faster than gwe's driver. * Started working on `DatabaseMetaData'. * The following methods are implemented: * `getTables()' * `getTableTypes()' * `getColumns()' * `getCatalogs()'  File: manual.info, Node: news-connector-mxj, Next: ccpp-news, Prev: cj-news, Up: news D.7 MySQL Connector/MXJ Change History ====================================== * Menu: * news-connector-mxj-5-0-11:: Changes in MySQL Connector/MXJ 5.0.11 (24th November 2009) * news-connector-mxj-5-0-10:: Changes in MySQL Connector/MXJ 5.0.10 (Never released) * news-connector-mxj-5-0-9:: Changes in MySQL Connector/MXJ 5.0.9 (19 August 2008) * news-connector-mxj-5-0-8:: Changes in MySQL Connector/MXJ 5.0.8 (06 August 2007) * news-connector-mxj-5-0-7:: Changes in MySQL Connector/MXJ 5.0.7 (27 May 2007) * news-connector-mxj-5-0-6:: Changes in MySQL Connector/MXJ 5.0.6 (04 May 2007) * news-connector-mxj-5-0-5:: Changes in MySQL Connector/MXJ 5.0.5 (14 March 2007) * news-connector-mxj-5-0-4:: Changes in MySQL Connector/MXJ 5.0.4 (28 January 2007) * news-connector-mxj-5-0-3:: Changes in MySQL Connector/MXJ 5.0.3 (24 June 2006) * news-connector-mxj-5-0-2:: Changes in MySQL Connector/MXJ 5.0.2 (15 June 2006) * news-connector-mxj-5-0-1:: Changes in MySQL Connector/MXJ 5.0.1 (Never released) * news-connector-mxj-5-0-0:: Changes in MySQL Connector/MXJ 5.0.0 (09 December 2005)  File: manual.info, Node: news-connector-mxj-5-0-11, Next: news-connector-mxj-5-0-10, Prev: news-connector-mxj, Up: news-connector-mxj D.7.1 Changes in MySQL Connector/MXJ 5.0.11 (24th November 2009) ---------------------------------------------------------------- *Functionality added or changed:* * The embedded MySQL binaries have been updated to MySQL 5.1.40 for GPL releases and MySQL 5.1.40 for Commercial releases. * The contents of the directory used for bootstrapping the MySQL databases is now configurable by using the `windows-share-dir-jar' property. You should supply the name of a jar containing the files you want to use. * The embedded Aspect/J class has been removed. * The default timeout for the kill delay within the embedded test suite has been increased from 10 to 30 seconds. *Bugs fixed:* * On startup Connector/MXJ generated an exception on Windows 7: Exception in thread "Thread-3" java.util.MissingResourceException?: Resource `5-0-51a/Windows_7-x86/mysqld-nt.exe' not found at com.mysql.management.util.Streams.getResourceAsStream(Streams.java:133) at com.mysql.management.util.Streams.getResourceAsStream(Streams.java:107) at com.mysql.management.util.Streams$1.inner(Streams.java:149) at com.mysql.management.util.Exceptions$VoidBlock?.exec(Exceptions.java:128) at com.mysql.management.util.Streams.createFileFromResource(Streams.java:162) at com.mysql.management.MysqldResource?.makeMysqld(MysqldResource?.java:533) at com.mysql.management.MysqldResource?.deployFiles(MysqldResource?.java:518) at com.mysql.management.MysqldResource?.exec(MysqldResource?.java:495) at com.mysql.management.MysqldResource?.start(MysqldResource?.java:216) at com.mysql.management.MysqldResource?.start(MysqldResource?.java:166) The default `platform-map.properties' file, which maps platforms to the supplied binary bundles, has been updated with additional platforms, including Windows 7, Windows Server 2008, `amd64' and `sparcv9' for Solaris, and Mac OS X 64-bit. (Bug #48298)  File: manual.info, Node: news-connector-mxj-5-0-10, Next: news-connector-mxj-5-0-9, Prev: news-connector-mxj-5-0-11, Up: news-connector-mxj D.7.2 Changes in MySQL Connector/MXJ 5.0.10 (Never released) ------------------------------------------------------------ This was an internal only release. *Functionality added or changed:* * The embedded MySQL has been updated to the MySQL 5.1 series. The embedded MySQL binaries have been updated to MySQL 5.1.33 for GPL releases and MySQL 5.1.34 for Commercial releases. * The MySQL binary for Windows targets has been updated to be configurable through the `windows-mysqld-command' property. This is to handle the move in MySQL 5.1.33 from *Note `mysqld-nt.exe': mysqld. to *Note `mysqld.exe': mysqld. The default value is *Note `mysqld.exe': mysqld.  File: manual.info, Node: news-connector-mxj-5-0-9, Next: news-connector-mxj-5-0-8, Prev: news-connector-mxj-5-0-10, Up: news-connector-mxj D.7.3 Changes in MySQL Connector/MXJ 5.0.9 (19 August 2008) ----------------------------------------------------------- *Functionality added or changed:* * The port used in the `ConnectorMXJUrlTestExample' and `ConnectorMXJObjectTestExample' port is no longer hard coded. Instead, the code uses the `x-mxj_test_port' property a default value of `3336' * The utility used to kill MySQL on Windows (`kill.exe') has been configured to be loaded from the `kill.exe' property, instead of being hard-coded. The corresponding timeout, `KILL_DELAY' has also been moved to the properties file and defaults to 5 minutes. * The embedded MySQL binaries have been updated to MySQL 5.0.51a for GPL releases and MySQL 5.0.54 for Commercial releases. * The timeout for kill operations in the embedded test suite has been set to a default of 10 seconds.  File: manual.info, Node: news-connector-mxj-5-0-8, Next: news-connector-mxj-5-0-7, Prev: news-connector-mxj-5-0-9, Up: news-connector-mxj D.7.4 Changes in MySQL Connector/MXJ 5.0.8 (06 August 2007) ----------------------------------------------------------- *Functionality added or changed:* * The embedded documentation has been updated so that it now points to the main MySQL documentation pages in the MySQL reference manual. * The embedded MySQL binaries have been updated to MySQL 5.0.45 for GPL releases and MySQL 5.0.46 for Commercial releases.  File: manual.info, Node: news-connector-mxj-5-0-7, Next: news-connector-mxj-5-0-6, Prev: news-connector-mxj-5-0-8, Up: news-connector-mxj D.7.5 Changes in MySQL Connector/MXJ 5.0.7 (27 May 2007) -------------------------------------------------------- *Functionality added or changed:* * Updated the jar filename to be consistent with the Connector/J jar filename. Files are now formatted as `mysql-connector-mxj-MXJ-VERSION'. * The `ConnectorMXJUrlTestExample' and `ConnectorMXJObjectTestExammple' have been updated to include an example of initializing the user/password and creating an initial database. The `InitializePasswordExample' example class has now been removed. * The `PatchedStandardSocketFactory' class has been removed, because it fixed an issue in Connector/J that was corrected in Connector/J 5.0.6. * The embedded MySQL binaries have been updated to MySQL 5.0.41 for GPL releases and MySQL 5.0.42 for Commercial releases. *Bugs fixed:* * Added a null-check to deal with class loaders where `getClassLoader()' returns null.  File: manual.info, Node: news-connector-mxj-5-0-6, Next: news-connector-mxj-5-0-5, Prev: news-connector-mxj-5-0-7, Up: news-connector-mxj D.7.6 Changes in MySQL Connector/MXJ 5.0.6 (04 May 2007) -------------------------------------------------------- *Functionality added or changed:* * Updated internal jar file names to include version information and be more consistent with Connector/J jar naming. For example, `connector-mxj.jar' is now `mysql-connector-mxj-${mxj-version}.jar'. * Updated commercial license files. * Added copyright notices to some classes which were missing them. * Added InitializeUser and QueryUtil classes to support new feature. * Added new tests for initial-user & expanded some existing tests. * ConnectorMXJUrlTestExample and ConnectorMXJObjectTestExample now demonstrate the initialization of user/password and creating the initial database (rather than using "test"). * Added new connection property `initialize-user' which, if set to `true' will remove the default, un-passworded anonymous and root users, and create the user/password from the connection url. * Removed obsolete field `SimpleMysqldDynamicMBean.lastInvocation'. * Clarified code in `DefaultsMap.entrySet()'. * Removed obsolete `PatchedStandardSocketFactory' java file. * Added `main(String[])' to `com/mysql/management/AllTestsSuite.java'. * Errors reading `portFile' are now reported using `stacktrace(err)', previously `System.err' was used. * `portFile' now contains a new-line to be consistent with `pidFile'. * Fixed where versionString.trim() was ignored. * Removed references to File.deleteOnExit, a warning is printed instead. *Bugs fixed:* * Changed tests to shutdown mysqld prior to deleting files. * Fixed port file to always be written to datadir. * Added os.name-os.arch to resource directory mapping properties file. * Swapped out commercial binaries for v5.0.40. * Delete `portFile' on shutdown. * Moved `platform-map.properties' into `db-files.jar'. * Clarified the startup max wait numbers. * Updated `build.xml' in preperation for next beta build. * Removed `use-default-architecture' property replaced. * Added null-check to deal with C/MXJ being loaded by the bootstrap classloaders with JVMs for which `getClassLoader()' returns null. * Added robustness around reading portfile. * Removed `PatchedStandardSocketFactory' (fixed in Connector/J 5.0.6). * Refactored duplication from tests and examples to QueryUtil. * Removed obsolete InitializePasswordExample  File: manual.info, Node: news-connector-mxj-5-0-5, Next: news-connector-mxj-5-0-4, Prev: news-connector-mxj-5-0-6, Up: news-connector-mxj D.7.7 Changes in MySQL Connector/MXJ 5.0.5 (14 March 2007) ---------------------------------------------------------- *Bugs fixed:* * Moved `MysqldFactory' to main package. * Reformatting: Added newlines some files which did not end in them. * Swapped out commercial binaries for v5.0.36. * Found and removed dynamic linking in mysql_kill; updated solution. * Changed protected constructor of `SimpleMysqldDynamicMBean' from taking a `MysqldResource' to taking a `MysqldFactory', to lay groundwork for addressing BUG discovered by Andrew Rubinger. See: 143046#msg-143046MySQL Forums (Actual testing with JBoss, and filing a bug, is still required.) * `build.xml': `usage' now slightly more verbose; some reformatting. * Now incorporates Reggie Bernett's `SafeTerminateProcess' and only calls the unsafe TerminateProcess as a final last resort. * New windows `kill.exe' fixes a bug where mysqld was being force terminated. Issue reported by bruno haleblian and others, see: 140623#msg-140623MySQL Forums. * Replaced `Boolean.parseBoolean' with JDK 1.4 compliant `valueOf'. * Changed `connector-mxj.properties' default mysql version to 5.0.37. * In testing so far mysqld reliably shuts down cleanly much faster. * Added testcase to `com.mysql.management.jmx.AcceptanceTest' which demonstrates that `dataDir' is a mutable MBean property. * Updated `build.xml' in prep for next release. * Changed `SimpleMysqldDynamicMBean' to create `MysqldResource' on demand to enable setting of `datadir'. (Rubinger bug groundwork). * Clarified the synchronization of `MysqldResource' methods. * `SIGHUP' is replaced with `MySQLShutdown' event. * Clarified the immutability of `baseDir', `dataDir', `pidFile', `portFile'. * Added 5.1.15 binaries to the repository. * Removed 5.1.14 binaries from the repository. * Added `getDataDir()' to interface `MysqldResourceI'. * Added 5.1.14 binaries to repository. * Replaced windows *Note `kill.exe': kill. resource with re-written version specific to mysqld. * Added Patched `StandardSocketFactory' from Connector/J 5-0 HEAD. * Ensured 5.1.14 compatibility. * Swapped out gpl binaries for v5.0.37. * Removed 5.0.22 binaries from the repository.  File: manual.info, Node: news-connector-mxj-5-0-4, Next: news-connector-mxj-5-0-3, Prev: news-connector-mxj-5-0-5, Up: news-connector-mxj D.7.8 Changes in MySQL Connector/MXJ 5.0.4 (28 January 2007) ------------------------------------------------------------ *Bugs fixed:* * Allow multiple calls to start server from URL connection on non-3306 port. (Bug #24004) * Updated `build.xml' to build to handle with different gpl and commercial mysqld version numbers. * Only populate the options map from the help text if specifically requested or in the MBean case. * Introduced property for Linux & WinXX to default to 32bit versions. * Swapped out gpl binaries for v5.0.27. * Swapped out commercial binaries for v5.0.32. * Moved mysqld binary resourced into separate jar file NOTICE: `CLASSPATH' will now need to `connector-mxj-db-files.jar'. * Minor test robustness improvements. * Moved default version string out of java class into a text editable properties file (`connector-mxj.properties') in the resources directory. * Fixed test to be tollerant of `/tmp' being a symlink to `/foo/tmp'.  File: manual.info, Node: news-connector-mxj-5-0-3, Next: news-connector-mxj-5-0-2, Prev: news-connector-mxj-5-0-4, Up: news-connector-mxj D.7.9 Changes in MySQL Connector/MXJ 5.0.3 (24 June 2006) --------------------------------------------------------- *Bugs fixed:* * Removed unused imports, formatted code, made minor edits to tests. * Removed "TeeOutputStream" - no longer needed. * Swapped out the mysqld binaries for MySQL v5.0.22.  File: manual.info, Node: news-connector-mxj-5-0-2, Next: news-connector-mxj-5-0-1, Prev: news-connector-mxj-5-0-3, Up: news-connector-mxj D.7.10 Changes in MySQL Connector/MXJ 5.0.2 (15 June 2006) ---------------------------------------------------------- *Bugs fixed:* * Replaced string parsing with JDBC connection attempt for determining if a mysqld is "ready for connections" `CLASSPATH' will now need to include Connector/J jar. * "platform" directories replace spaces with underscores * extracted array and list printing to ListToString utility class * Swapped out the mysqld binaries for MySQL v5.0.21 * Added trace level logging with Aspect/J. `CLASSPATH' will now need to include `lib/aspectjrt.jar' * reformatted code * altered to be "basedir" rather than "port" oriented. * help parsing test reflects current help options * insulated users from problems with "." in basedir * swapped out the mysqld binaries for MySQL v5.0.18 * Made tests more robust be deleting the /tmp/test-c.mxj directory before running tests. * ServerLauncherSocketFactory.shutdown API change: now takes File parameter (basedir) instead of port. * socket is now "mysql.sock" in datadir * added ability to specify "mysql-version" as an url parameter * Extended timeout for help string parsing, to avoid cases where the help text was getting prematurely flushed, and thus truncated. * swapped out the mysqld binaries for MySQL v5.0.19 * MysqldResource now tied to dataDir as well as basedir (API CHANGE) * moved PID file into datadir * ServerLauncherSocketFactory.shutdown now works across JVMs. * extracted splitLines(String) to Str utility class * ServerLauncherSocketFactory.shutdown(port) no longer throws, only reports to System.err * ServerLauncherSocketFactory now treats URL parameters in the form of `&server.foo=null' as `serverOptionMap.put("foo", null)' * ServerLauncherSocketFactory.shutdown API change: now takes 2 File parameters (basedir, datadir)  File: manual.info, Node: news-connector-mxj-5-0-1, Next: news-connector-mxj-5-0-0, Prev: news-connector-mxj-5-0-2, Up: news-connector-mxj D.7.11 Changes in MySQL Connector/MXJ 5.0.1 (Never released) ------------------------------------------------------------ This was an internal only release. This section has no changelog entries.  File: manual.info, Node: news-connector-mxj-5-0-0, Prev: news-connector-mxj-5-0-1, Up: news-connector-mxj D.7.12 Changes in MySQL Connector/MXJ 5.0.0 (09 December 2005) -------------------------------------------------------------- *Bugs fixed:* * Removed HelpOptionsParser's need to reference a MysqldResource. * Reorganized utils into a single "Utils" collaborator. * Minor test tweaks * Altered examples and tests to use new Connector/J 5.0 URL syntax for launching Connector/MXJ ("jdbc:mysql:mxj://") * Swapped out the mysqld binaries for MySQL v5.0.16. * Ditched "ClassUtil" (merged with Str). * Minor refactorings for type casting and exception handling.  File: manual.info, Node: ccpp-news, Next: mysql-proxy-news, Prev: news-connector-mxj, Up: news D.8 MySQL Connector/C++ Change History ====================================== * Menu: * ccpp-news-1-1:: Changes in MySQL Connector/C++ 1.1.x * ccpp-news-1-0:: Changes in MySQL Connector/C++ 1.0.x  File: manual.info, Node: ccpp-news-1-1, Next: ccpp-news-1-0, Prev: ccpp-news, Up: ccpp-news D.8.1 Changes in MySQL Connector/C++ 1.1.x ------------------------------------------ * Menu: * ccpp-news-1-1-0:: Changes in MySQL Connector/CPP 1.1.0 (13th September 2010 GA)  File: manual.info, Node: ccpp-news-1-1-0, Prev: ccpp-news-1-1, Up: ccpp-news-1-1 D.8.1.1 Changes in MySQL Connector/CPP 1.1.0 (13th September 2010 GA) ..................................................................... This fixes bugs since the first GA release 1.0.5 and introduces new features. *Functionality added or changed:* * *Incompatible Change*: API incompatible change: `ConnectPropertyVal' is no longer a `struct' by a typedef that uses `boost::variant'. Code such as: sql::ConnectPropertyVal tmp; tmp.str.val=passwd.c_str(); tmp.str.len=passwd.length(); connection_properties["password"] = tmp; Should be changed to: connection_properties["password"] = sql::ConnectPropertyVal(passwd); * Instances of `std::auto_ptr' have been changed to `boost::scoped_ptr'. Scoped array instances now use boost::scoped_array. Further, `boost::shared_ptr' and `boost::weak_ptr' are now used for guarding access around result sets. * `LDFLAGS', `CXXFLAGS' and `CPPFLAGS' are now checked from the environment for every binary generated. * Connection map property `OPT_RECONNECT' was changed to be of type `boolean' from `long' `long'. * `get_driver_instance()' is now only available in dynamic library builds - static builds do not have this symbol. This was done to accommodate loading the DLL with `LoadLibrary' or `dlopen'. If you do not use `CMake' for building the source code you will need to define `mysqlcppconn_EXPORTS' if you are loading dynamically and want to use the `get_driver_instance()' entry point. * `Connection::getClientOption(const sql::SQLString & optionName, void * optionValue)' now accepts the `optionName' values `metadataUseInfoSchema', `defaultStatementResultType', `defaultPreparedStatementResultType', and `characterSetResults'. In the previous version only `metadataUseInfoSchema' was permitted. The same options are available for `Connection::setClientOption()'. *Bugs fixed:* * Certain header files were incorrectly present in the source distribution. The fix excludes dynamically generated and platform specific header files from source packages generated using CPack. (Bug #45846) * `CMake' generated an error if configuring an out of source build, that is, when `CMake' was not called from the source root directory. (Bug #45843) * Using Prepared Statements caused corruption of the heap. (Bug #45048) * Missing includes when using GCC 4.4. Note that GCC 4.4 is not yet in use for any official MySQL Connector/C++ builds. (Bug #44931) * A bug was fixed in Prepared Statements. The bug occurred when a stored procedure was prepared without any parameters. This led to an exception. (Bug #44931) * Fixed a Prepared Statements performance issue. Reading large result sets was slow. * Fixed bug in `ResultSetMetaData' for statements and prepared statements, `getScale' and `getPrecision' returned incorrect results.  File: manual.info, Node: ccpp-news-1-0, Prev: ccpp-news-1-1, Up: ccpp-news D.8.2 Changes in MySQL Connector/C++ 1.0.x ------------------------------------------ * Menu: * ccpp-news-1-0-5:: Changes in MySQL Connector/CPP 1.0.5 (21 April 2009) * ccpp-news-1-0-4:: Changes in MySQL Connector/CPP 1.0.4 (31 March 2009 beta) * ccpp-news-1-0-3:: Changes in MySQL Connector/CPP 1.0.3 (02 March 2009 alpha) * ccpp-news-1-0-2:: Changes in MySQL Connector/CPP 1.0.2 (19 December 2008 alpha) * ccpp-news-1-0-1:: Changes in MySQL Connector/CPP 1.0.1 (01 December 2008 alpha)  File: manual.info, Node: ccpp-news-1-0-5, Next: ccpp-news-1-0-4, Prev: ccpp-news-1-0, Up: ccpp-news-1-0 D.8.2.1 Changes in MySQL Connector/CPP 1.0.5 (21 April 2009) ............................................................ This is the first Generally Available (GA) release. *Functionality added or changed:* * The interface of `sql::ConnectionMetaData', `sql::ResultSetMetaData' and `sql::ParameterMetaData' was modified to have a protected destructor. As a result the client code has no need to destruct the metadata objects returned by the connector. MySQL Connector/C++ handles the required destruction. This enables statements such as: connection->getMetaData->getSchema(); This avoids potential memory leaks that could occur as a result of losing the pointer returned by `getMetaData()'. * Improved memory management. Potential memory leak situations are handled more robustly. * Changed the interface of `sql::Driver' and `sql::Connection' so they accept the options map by alias instead of by value. * Changed the return type of `sql::SQLException::getSQLState()' from `std::string' to `const char *' to be consistent with `std::exception::what()'. * Implemented `getResultSetType()' and `setResultSetType()' for `Statement'. Uses `TYPE_FORWARD_ONLY', which means unbuffered result set and `TYPE_SCROLL_INSENSITIVE', which means buffered result set. * Implemented `getResultSetType()' for `PreparedStatement'. The setter is not implemented because currently `PreparedStatement' cannot do refetching. Storing the result means the bind buffers will be correct. * Added the option `defaultStatementResultType' to `MySQL_Connection::setClientOption()'. Also, the method now returns `sql::Connection *'. * Added `Result::getType()'. Implemented for the three result set classes. * Enabled tracing functionality when building with Microsoft Visual C++ 8 and later, which corresponds to Microsoft Visual Studio 2005 and later. * Added better support for named pipes, on Windows. Use `pipe://' and add the path to the pipe. Shared memory connections are currently not supported. *Bugs fixed:* * A bug was fixed in `MySQL_Connection::setSessionVariable()', which had been causing exceptions to be thrown.  File: manual.info, Node: ccpp-news-1-0-4, Next: ccpp-news-1-0-3, Prev: ccpp-news-1-0-5, Up: ccpp-news-1-0 D.8.2.2 Changes in MySQL Connector/CPP 1.0.4 (31 March 2009 beta) ................................................................. *Functionality added or changed:* * An installer was added for the Windows operating system. * Minimum `CMake' version required was changed from 2.4.2 to 2.6.2. The latest version is required for building on Windows. * `metadataUseInfoSchema' was added to the connection property map, which enables control of the `INFORMATION_SCHEMA' for metadata. * Implemented `MySQL_ConnectionMetaData::supportsConvert(from, to)'. * Added support for MySQL Connector/C. * Introduced `ResultSetMetaData::isZerofill()', which is not in the JDBC specification. *Bugs fixed:* * A bug was fixed in all implementations of `ResultSet::relative()' which was giving a wrong return value although positioning was working correctly. * A leak was fixed in `MySQL_PreparedResultSet', which occurred when the result contained a `BLOB' column.  File: manual.info, Node: ccpp-news-1-0-3, Next: ccpp-news-1-0-2, Prev: ccpp-news-1-0-4, Up: ccpp-news-1-0 D.8.2.3 Changes in MySQL Connector/CPP 1.0.3 (02 March 2009 alpha) .................................................................. *Functionality added or changed:* * Added new tests in `test/unit/classes'. Those tests are mostly about code coverage. Most of the actual functionality of the driver is tested by the tests found in `test/CJUnitPort'. * New data types added to the list returned by `DatabaseMetaData::getTypeInfo()' are `FLOAT UNSIGNED', `DECIMAL UNSIGNED', `DOUBLE UNSIGNED'. Those tests may not be in the JDBC specification. However, due to the change you should be able to look up every type and type name returned by, for example, `ResultSetMetaData::getColumnTypeName()'. * `MySQL_Driver::getPatchVersion' introduced. * Major performance improvements due to new buffered `ResultSet' implementation. * Addition of `test/unit/README' with instructions for writing bug and regression tests. * Experimental support for STLPort. This feature may be removed again at any time later without prior warning! Type `cmake `-L'' for configuration instructions. * Added properties enabled methods for connecting, which add many connect options. This uses a dictionary (map) of key value pairs. Methods added are `Driver::connect(map)', and `Connection::Connection(map)'. * New BLOB implementation. `sql::Blob' was removed in favor of `std::istream'. C++'s `IOStream' library is very powerful, similar to PHP's streams. It makes no sense to reinvent the wheel. For example, you can pass a `std::istringstream' object to `setBlob()' if the data is in memory, or just open a file `std::fstream' and let it stream to the DB, or write its own stream. This is also true for `getBlob()' where you can just copy data (if a buffered result set), or stream data (if implemented). * Implemented `ResultSet::getBlob()' which returns `std::stream'. * Fixed `MySQL_DatabaseMetaData::getTablePrivileges()'. Test cases were added in the first unit testing framework. * Implemented `MySQL_Connection::setSessionVariable()' for setting variables like `sql_mode'. * Implemented `MySQL_DatabaseMetaData::getColumnPrivileges()'. * `cppconn/datatype.h' has changed and is now used again. Reimplemented the type subsystem to be more usable - more types for binary and nonbinary strings. * Implementation for `MySQL_DatabaseMetaData::getImportedKeys()' for MySQL versions before 5.1.16 using `SHOW', and above using `INFORMATION_SCHEMA'. * Implemented `MySQL_ConnectionMetaData::getProcedureColumns()'. * `make package_source' now packs with bzip2. * Re-added `getTypeInfo()' with information about all types supported by MySQL and the `sql::DataType'. * Changed the implementation of `MySQL_ConstructedResultSet' to use the more efficient O(1) access method. This should improve the speed with which the metadata result sets are used. Also, there is less copying during the construction of the result set, which means that all result sets returned from the metadata functions will be faster. * Introduced, internally, `sql::mysql::MyVal' which has implicit constructors. Used in `mysql_metadata.cpp' to create result sets with native data instead of always string (varchar). * Renamed `ResultSet::getLong()' to `ResultSet::getInt64()'. `resultset.h' includes typdefs for Windows to be able to use `int64_t'. * Introduced `ResultSet::getUInt()' and `ResultSet::getUInt64()'. * Improved the implementation for `ResultSetMetaData::isReadOnly()'. Values generated from views are read only. These generated values don't have `db' in `MYSQL_FIELD' set, while all normal columns do have. * Implemented `MySQL_DatabaseMetaData::getExportedKeys()'. * Implemented `MySQL_DatabaseMetaData::getCrossReference()'. *Bugs fixed:* * Bug fixed in `MySQL_PreparedResultSet::getString()'. Returned string that had real data but the length was random. Now, the string is initialized with the correct length and thus is binary safe. * Corrected handling of unsigned server types. Now returning correct values. * Fixed handling of numeric columns in `ResultSetMetaData::isCaseSensitive' to return `false'.  File: manual.info, Node: ccpp-news-1-0-2, Next: ccpp-news-1-0-1, Prev: ccpp-news-1-0-3, Up: ccpp-news-1-0 D.8.2.4 Changes in MySQL Connector/CPP 1.0.2 (19 December 2008 alpha) ..................................................................... *Functionality added or changed:* * Implemented `getScale()', `getPrecision()' and `getColumnDisplaySize()' for `MySQL_ResultSetMetaData' and `MySQL_Prepared_ResultSetMetaData'. * Changed `ResultSetMetaData' methods `getColumnDisplaySize()', `getPrecision()', `getScale()' to return `unsigned int' instead of `signed int'. * `DATE', `DATETIME' and `TIME' are now being handled when calling the `MySQL_PreparedResultSet' methods `getString()', `getDouble()', `getInt()', `getLong()', `getBoolean()'. * Reverted implementation of `MySQL_DatabaseMetaData::getTypeInfo()'. Now unimplemented. In addition, removed `cppconn/datatype.h' for now, until a more robust implementation of the types can be developed. * Implemented `MySQL_PreparedStatement::setNull()'. * Implemented `MySQL_PreparedStatement::clearParameters()'. * Added PHP script `examples/cpp_trace_analyzer.php' to filter the output of the debug trace. Please see the inline comments for documentation. This script is unsupported. * Implemented `MySQL_ResultSetMetaData::getPrecision()' and `MySQL_Prepared_ResultSetMetaData::getPrecision()', updating example. * Added new unit test framework for JDBC compliance and regression testing. * Added `test/unit' as a basis for general unit tests using the new test framework, see `test/unit/example' for basic usage examples. *Bugs fixed:* * Fixed `MySQL_PreparedStatementResultSet::getDouble()' to return the correct value when the underlying type is `MYSQL_TYPE_FLOAT'. * Fixed bug in `MySQL_ConnectionMetaData::getIndexInfo()'. The method did not work because the schema name wasn't included in the query sent to the server. * Fixed a bug in `MySQL_ConnectionMetaData::getColumns()' which was performing a cartesian product of the columns in the table times the columns matching `columnNamePattern'. The example `example/connection_meta_schemaobj.cpp' was extended to cover the function. * Fixed bugs in `MySQL_DatabaseMetaData'. All `supportsCatalogXXXXX' methods were incorrectly returning `true' and all `supportsSchemaXXXX' methods were incorrectly returning `false'. Now `supportsCatalogXXXXX' returns `false' and `supportsSchemaXXXXX' returns `true'. * Fixed bugs in the `MySQL_PreparedStatements' methods `setBigInt()' and `setDatetime()'. They decremented the internal column index before forwarding the request. This resulted in a double-decrement and therefore the wrong internal column index. The error message generated was: setString() ... invalid "parameterIndex" * Fixed a bug in `getString()'. `getString()' is now binary safe. A new example was also added. * Fixed bug in `FLOAT' handling. * Fixed `MySQL_PreparedStatement::setBlob()'. In the tests there is a simple example of a class implementing `sql::Blob'.  File: manual.info, Node: ccpp-news-1-0-1, Prev: ccpp-news-1-0-2, Up: ccpp-news-1-0 D.8.2.5 Changes in MySQL Connector/CPP 1.0.1 (01 December 2008 alpha) ..................................................................... *Functionality added or changed:* * `sql::mysql::MySQL_SQLException' was removed. The distinction between server and client (connector) errors, based on the type of the exception, has been removed. However, the error code can still be checked to evaluate the error type. * Support for (n)make install was added. You can change the default installation path. Carefully read the messages displayed after executing cmake. The following are installed: * Static and the dynamic version of the library, `libmysqlcppconn'. * Generic interface, `cppconn'. * Two MySQL specific headers: `mysql_driver.h', use this if you want to get your connections from the driver instead of instantiating a `MySQL_Connection' object. This makes your code portable when using the common interface. `mysql_connection.h', use this if you intend to link directly to the `MySQL_Connection' class and use its specifics not found in `sql::Connection'. However, you can make your application fully abstract by using the generic interface rather than these two headers. * Driver Manager was removed. * Added `ConnectionMetaData::getSchemas()' and `Connection::setSchema()'. * `ConnectionMetaData::getCatalogTerm()' returns not applicable, there is no counterpart to catalog in MySQL Connector/C++. * Added experimental GCov support, `cmake `-DMYSQLCPPCONN_GCOV_ENABLE:BOOL=1'' * All examples can be given optional connection parameters on the command line, for example: examples/connect tcp://host:port user pass database or examples/connect unix:///path/to/mysql.sock user pass database * Renamed `ConnectionMetaData::getTables: TABLE_COMMENT' to `REMARKS'. * Renamed `ConnectionMetaData::getProcedures: PROCEDURE_SCHEMA' to `PROCEDURE_SCHEM'. * Renamed `ConnectionMetaData::getPrimaryKeys(): COLUMN' to `COLUMN_NAME', `SEQUENCE' to `KEY_SEQ', and `INDEX_NAME' to `PK_NAME'. * Renamed `ConnectionMetaData::getImportedKeys(): PKTABLE_CATALOG' to `PKTABLE_CAT', `PKTABLE_SCHEMA' to `PKTABLE_SCHEM', `FKTABLE_CATALOG' to `FKTABLE_CAT', `FKTABLE_SCHEMA' to `FKTABLE_SCHEM'. * Changed metadata column name `TABLE_CATALOG' to `TABLE_CAT' and `TABLE_SCHEMA' to `TABLE_SCHEM' to ensure JDBC compliance. * Introduced experimental CPack support, see make help. * All tests changed to create TAP compliant output. * Renamed `sql::DbcMethodNotImplemented' to `sql::MethodNotImplementedException' * Renamed `sql::DbcInvalidArgument' to `sql::InvalidArgumentException' * Changed `sql::DbcException' to implement the interface of JDBC's `SQLException'. Renamed to `sql::SQLException'. * Converted Connector/J tests added. * MySQL Workbench 5.1 changed to use MySQL Connector/C++ for its database connectivity. * New directory layout.  File: manual.info, Node: mysql-proxy-news, Prev: ccpp-news, Up: news D.9 MySQL Proxy Change History ============================== * Menu: * mysql-proxy-news-0-8-1:: Changes in MySQL Proxy 0.8.1 (13 September 2010) * mysql-proxy-news-0-8-0:: Changes in MySQL Proxy 0.8.0 (21 January 2010) * mysql-proxy-news-0-7-2:: Changes in MySQL Proxy 0.7.2 (30 June 2009) * mysql-proxy-news-0-7-1:: Changes in MySQL Proxy 0.7.1 (15 May 2009) * mysql-proxy-news-0-7-0:: Changes in MySQL Proxy 0.7.0 (Not Released) * mysql-proxy-news-0-6-1:: Changes in MySQL Proxy 0.6.1 (06 February 2008) * mysql-proxy-news-0-6-0:: Changes in MySQL Proxy 0.6.0 (11 September 2007) * mysql-proxy-news-0-5-1:: Changes in MySQL Proxy 0.5.1 (30 June 2007) * mysql-proxy-news-0-5-0:: Changes in MySQL Proxy 0.5.0 (19 June 2007)  File: manual.info, Node: mysql-proxy-news-0-8-1, Next: mysql-proxy-news-0-8-0, Prev: mysql-proxy-news, Up: mysql-proxy-news D.9.1 Changes in MySQL Proxy 0.8.1 (13 September 2010) ------------------------------------------------------ *Functionality added or changed:* * Allow interception of *Note `LOAD DATA INFILE': load-data. and *Note `SHOW ERRORS': show-errors. statements. * The unused `network_mysqld_com_query_result_track_state()' function has been deprecated. * `chassis_set_fdlimit()' has been deprecated in favor of `chassis_fdlimit_set()'. * Shutdown hooks were added to free the global memory of third-party libraries such as `openssl'. * `con->in_load_data_local' has been removed. *Bugs fixed:* * The admin plugin had an undocumented default value for `--admin-password'. (Bug #53429) * Use of *Note `LOAD DATA LOCAL INFILE': load-data. caused the connection between the client and MySQL Proxy to abort. (Bug #51864) * If the backend MySQL server went down, and then the clock on the MySQL Proxy host went backward (for example, during daylight saving time adjustments), Proxy stopped forwarding queries to the backend. (Bug #50806) * `network_address_set_address()->network_address_set_address_ip()' called `gethostbyname()' which was not reentrant. This meant that a MySQL Proxy plugin needed to guard all calls to `network_address_set_address()' with a mutex. `network_address_set_address()' has been modified to be thread safe. (Bug #49099) * The hard limit was fixed for the case where the fdlimit was set. (Bug #48120) * MySQL Proxy returned an error message with a nonstandard SQL State when all backends were down: "#07000(proxy) all backends are down" This caused issues for clients with `retry' logic, as they could not handle these `custom' SQL States. (Bug #45417) * If MySQL Proxy used a UNIX socket, it did not remove the socket file at termination time. (Bug #38415) * The `--proxy-read-only-backend-addresses' option did not work. (Bug #38341, Bug #11749171) * When running `configure' to build, the error message relating to the `lua' libraries could be misleading. The wording and build advice have been updated.  File: manual.info, Node: mysql-proxy-news-0-8-0, Next: mysql-proxy-news-0-7-2, Prev: mysql-proxy-news-0-8-1, Up: mysql-proxy-news D.9.2 Changes in MySQL Proxy 0.8.0 (21 January 2010) ---------------------------------------------------- *Functionality added or changed:* * The `--no-daemon' has been renamed to The `--daemon'. By default, MySQL Proxy now starts in foreground mode. Use the `--daemon' option to override this and start in daemon mode. *Bugs fixed:* * A memory leak occurred in MySQL Proxy if clients older than MySQL 4.1 connected to it. (Bug #50993) * A segmentation fault occurred in MySQL Proxy if clients older than MySQL 4.1 connected to it. (Bug #48641) * MySQL Proxy would load a configuration file with unsafe permissions, which could permit password information to be exposed through the file. MySQL Proxy now refuses to load a configuration file with unsafe permissions. (Bug #47589) * Several supplied scripts were updated to account for flag and structure changes: * `active-transactions.lua' was updated to use the `resultset_is_needed' flag. * `ro-balance.lua' was updated to use the `resultset_is_needed' flag and updated `proxy.connection.dst.name' structure. * `rw-splitting.lua' was updated to use the `resultset_is_needed' flag and updated `proxy.connections' structure. (Bug #47349, Bug #45408, Bug #47345, Bug #43424, Bug #42841, Bug #46141) * The line numbers provided in stack traces were off by one. (Bug #47348) * MySQL Proxy accepted more than one address in the value of the `--proxy-backend-addresses' option. You should specify one `--proxy-backend-addresses' option for each backend address. (Bug #47273) * MySQL Proxy returned the wrong version string internally from the `proxy.PROXY_VERSION' constant. (Bug #45996) * MySQL Proxy could stop accepting network packets if it received a large number of packets. The listen queue has been extended to permit a larger backlog. (Bug #45878, Bug #43278) * Due to a memory leak, memory usage for each new connection to the proxy increased, leading to very high consumption. (Bug #45272) * MySQL Proxy failed to work with certain versions of MySQL, including MySQL 5.1.15, where a change in the MySQL protocol existed. Now Proxy denies `COM_CHANGE_USER' commands when it is connected to MySQL 5.1.14 to 5.1.17 servers by sending back an error: `COM_CHANGE_USER is broken on 5.1.14-.17, please upgrade the MySQL Server'. (Bug #45167) See also Bug #25371. * Logging to `syslog' with the `--log-use-syslog' option did not work. (Bug #36431) * MySQL Proxy could incorrectly insert `NULL' values into the returned result set, even though non-`NULL' values were returned in the original query. (Bug #35729) * MySQL Proxy raised an error when processing query packets larger than 16MB. (Bug #35202)  File: manual.info, Node: mysql-proxy-news-0-7-2, Next: mysql-proxy-news-0-7-1, Prev: mysql-proxy-news-0-8-0, Up: mysql-proxy-news D.9.3 Changes in MySQL Proxy 0.7.2 (30 June 2009) ------------------------------------------------- *Bugs fixed:* * On Windows, MySQL Proxy might not find the required modules during initialization. The core code has been updated to find the components correctly, and the Lua-based C modules are prefixed with `lua-' and Lua plugins with `plugin-'. (Bug #45833)  File: manual.info, Node: mysql-proxy-news-0-7-1, Next: mysql-proxy-news-0-7-0, Prev: mysql-proxy-news-0-7-2, Up: mysql-proxy-news D.9.4 Changes in MySQL Proxy 0.7.1 (15 May 2009) ------------------------------------------------ *Bugs fixed:* * Due to a memory leak, memory usage for each new connection to the proxy increased, leading to very high consumption. (Bug #45272) * The port number was reported incorrectly in `proxy.connection.client.address'. (Bug #43313) * Result sets with more than 250 fields could cause MySQL Proxy to crash. (Bug #43078) * MySQL Proxy was unable to increase its own maximum number of open files according to the limit specified by the `--max-open-files' option, if the limit was less than 8192. When set to debug level, Proxy now reports the open files limit and when the limit has been updated. (Bug #42783) * MySQL Proxy crashed when connecting to a MySQL 4.0 server. Now it generates an error message instead. (Bug #38601) * When using the `rw-splitting.lua' script, you could get an error when talking to the backend server: 2008-07-28 18:00:30: (critical) (read_query) [string "/usr/local/share/mysql-proxy/rw-splitting.l..."]:218: bad argument #1 to 'ipairs' (table expected, got userdata) This led to Proxy closing the connection to the configured MySQL backend. (Bug #38419) * When using MySQL Proxy with multiple backends, failure of one backend caused Proxy to disconnect all backends and stop routing requests. (Bug #34793)  File: manual.info, Node: mysql-proxy-news-0-7-0, Next: mysql-proxy-news-0-6-1, Prev: mysql-proxy-news-0-7-1, Up: mysql-proxy-news D.9.5 Changes in MySQL Proxy 0.7.0 (Not Released) ------------------------------------------------- *Functionality added or changed:* * Support for using a configuration file, in addition to the command-line options, has been added. To specify such a file, use the `--defaults-file=`file_name'' command-line option. See *Note mysql-proxy-configuration::. (Bug #30206) * A number of the internal structures developed for use with Lua scripts that work with MySQL Proxy have been updated and harmonized to make their meaning and contents easier to use and consistent across multiple locations. * The address information has been updated. Instead of a combined `ip:port' structure that you had to parse to extract the individual information, you can now access that information directly. For example, instead of structures providing a single `.address' item, you now have these items: `name' (the combined `ip:port'), `address' (the IP address), and `port' (port number). In addition, all addresses now supply both the `src' (source) and `dst' (destination) socket information for both ends of connections. Some familiar structures have been updated to accommodate this information: * `proxy.connection.client.address' is `proxy.connection.client.src.name' * `proxy.connection.server.address' is `proxy.connection.server.dst.name' * `proxy.backends' is now in `proxy.global.backends' The `.address' field of each backend is an address-object as described earlier. For example, `proxy.backends[1].address' is `proxy.global.backends[1].dst.name'. * The `read_auth()' and `read_handshake()' functions no longer receive an `auth' parameter. Instead, all the data is available in the connection tables. In `read_handshake()', you access the information through the global `proxy.connection' table: 0.6 0.7 `auth.thread_id' `proxy.connection.server.thread_id' `auth.mysqld_version ' `proxy.connection.server.mysqld_version' `auth.server_addr ' `proxy.connection.server.dst.name' `auth.client_addr ' `proxy.connection.client.src.name' `auth.scramble ' `proxy.connection.server.scramble_buffer' In `read_auth()', you can use the following: 0.6 0.7 `auth.username' `proxy.connection.client.username' `auth.password ' `proxy.connection.client.scrambled_password' `auth.default_db ' `proxy.connection.client.default_db' `auth.server_addr ' `proxy.connection.server.dst.name' `auth.client_addr ' `proxy.connection.client.src.name' * In the `proxy.queries:append()' function, a third parameter is an (optional) table with options specific to the this packet. Specifically, if you want to have access to the result set in the `read_query_result()' hook, you must set the `resultset_is_needed' flag: proxy.queries:append( 1, ..., { resultset_is_needed = true } ) For more information, see *Note mysql-proxy-scripting-structures-queries::. * `proxy.backends' is now in `proxy.global.backends'. *Bugs fixed:* * *Security Enhancement*: Accessing MySQL Proxy using a client or backend from earlier than MySQL 4.1 resulted in Proxy aborting with an assertion. This is because Proxy supports only MySQL 4.1 or higher. Proxy now reports a fault. (Bug #31419) * MySQL Proxy was configured with the `LUA_PATH' and `LUA_CPATH' directory locations according to the build host rather than the execution host. In addition, during installation, certain Lua source files could be installed into the incorrect locations. (Bug #44877, Bug #44497) * Using MySQL Proxy with very large return data sets from queries could cause a crash, with or without manipulation of the data set within the Lua engine. (Bug #39332) * MySQL Proxy terminated if a submitted packet was smaller than expected by the protocol. (Bug #36743) * When using MySQL Proxy in a master-master replication scenario, Proxy failed to identify failure in one of the replication masters and did not redirect connections to the other master. (Bug #35295)  File: manual.info, Node: mysql-proxy-news-0-6-1, Next: mysql-proxy-news-0-6-0, Prev: mysql-proxy-news-0-7-0, Up: mysql-proxy-news D.9.6 Changes in MySQL Proxy 0.6.1 (06 February 2008) ----------------------------------------------------- *Functionality added or changed:* * Fixed assertions on write errors. * Fixed sending fake server-greetings in `connect_server()'. * Fixed error handling for socket functions on Windows. * Added new features to `run-tests.lua'.  File: manual.info, Node: mysql-proxy-news-0-6-0, Next: mysql-proxy-news-0-5-1, Prev: mysql-proxy-news-0-6-1, Up: mysql-proxy-news D.9.7 Changes in MySQL Proxy 0.6.0 (11 September 2007) ------------------------------------------------------ *Functionality added or changed:* * When using read/write splitting and the `rw-splitting.lua' example script, connecting a second user to the proxy returns an error message. (Bug #30867) * Added support in `read_query_result()' to overwrite the result set. * By default, MySQL Proxy now starts in daemon mode. Use the new `--no-daemon' option to override this. Added the `--pid-file' option for writing the process ID to a file after becoming a daemon. * Added hooks for `read_auth()', `read_handshake()' and `read_auth_result()'. * Added handling of `proxy.connection.backend_ndx' in `connect_server()' and `read_query()' to support read/write splitting. * Added support for `proxy.response.packets'. * Added test cases. * Added `--no-proxy' to disable the proxy. * Added support for listening UNIX sockets. * Added a global Lua-scope `proxy.global.*'. * Added connection pooling. *Bugs fixed:* * Fixed an assertion on `COM_BINLOG_DUMP'. (Bug #29764) * Fixed an assertion on result-packets like `[field-len | fields | EOF | ERR]'. (Bug #29732) * Fixed an assertion that MySQL Proxy raised at login time if a client specified no password and no default database. (Bug #29719) * Fixed an assertion at `COM_SHUTDOWN'. (Bug #29719) * Fixed a crash if `proxy.connection' is used in `connect_server()'. * Fixed the `glib2' check to require at least `glib2' 2.6.0. * Fixed an assertion at connect time when all backends are down. * Fixed connection stalling if `read_query_result()' raised an assertion. * Fixed length encoding on `proxy.resultsets'. * Fixed compilation on win32. * Fixed an assertion when connecting to MySQL 6.0.1. * Fixed decoding of length-encoded ints for 3-byte notation. * Fixed `inj.resultset.affected_rows' on *Note `SELECT': select. queries. * Fixed handling of (SQL) `NULL' in result sets. * Fixed a memory leak when `proxy.response.*' is used.  File: manual.info, Node: mysql-proxy-news-0-5-1, Next: mysql-proxy-news-0-5-0, Prev: mysql-proxy-news-0-6-0, Up: mysql-proxy-news D.9.8 Changes in MySQL Proxy 0.5.1 (30 June 2007) ------------------------------------------------- *Functionality added or changed:* * Added `resultset.affected_rows' and `resultset.insert_id'. * Changed `--proxy.profiling' to `--proxy-skip-profiling'. * Added missing dependency to `libmysqlclient-dev' to the `INSTALL' file. * Added `inj.query_time' and `inj.response_time' into the Lua scripts. * Added support for pre-4.1 passwords in a 4.1 connection. * Added script examples for rewriting and injection. * Added `proxy.VERSION'. * Added support for UNIX sockets. * Added protection against duplicate result sets from a script. *Bugs fixed:* * Fixed mysql check in `configure' to die when `mysql.h' isn't detected. * Fixed handling of duplicate ERR on `COM_CHANGE_USER' in MySQL 5.1.18+. * Fixed a compile error with MySQL 4.1.x on missing `COM_STMT_*'. * Fixed a crash on fields longer than 250 bytes when the result set is inspected. * Fixed a warning if `connect_server()' is not provided. * Fixed an assertion when an error occurs at initial script exec time. * Fixed an assertion when `read_query_result()' is not provided when `PROXY_SEND_QUERY' is used.  File: manual.info, Node: mysql-proxy-news-0-5-0, Prev: mysql-proxy-news-0-5-1, Up: mysql-proxy-news D.9.9 Changes in MySQL Proxy 0.5.0 (19 June 2007) ------------------------------------------------- This is the first beta release. *Bugs fixed:* * Added `automake'/`autoconf' support. * Added `CMake' support.  File: manual.info, Node: restrictions, Prev: news, Up: Top Appendix E Restrictions and Limits ********************************** * Menu: * stored-program-restrictions:: Restrictions on Stored Routines, Triggers, and Events * cursor-restrictions:: Restrictions on Server-Side Cursors * subquery-restrictions:: Restrictions on Subqueries * view-restrictions:: Restrictions on Views * xa-restrictions:: Restrictions on XA Transactions * charset-restrictions:: Restrictions on Character Sets * limits:: Limits in MySQL The discussion here describes restrictions that apply to the use of MySQL features such as subqueries or views.  File: manual.info, Node: stored-program-restrictions, Next: cursor-restrictions, Prev: restrictions, Up: restrictions E.1 Restrictions on Stored Routines, Triggers, and Events ========================================================= These restrictions apply to the features described in *Note stored-programs-views::. Some of the restrictions noted here apply to all stored routines; that is, both to stored procedures and stored functions. There are also some restrictions specific to stored functions but not to stored procedures. The restrictions for stored functions also apply to triggers. There are also some restrictions specific to triggers. The restrictions for stored procedures also apply to the *Note `DO': do. clause of Event Scheduler event definitions. There are also some restrictions specific to events. * SQL Statements Not Permitted in Stored Routines * Stored routines cannot contain arbitrary SQL statements. The following statements are not permitted: * The locking statements *Note `LOCK TABLES': lock-tables. and *Note `UNLOCK TABLES': lock-tables. * *Note `ALTER VIEW': alter-view. (Before MySQL 5.1.21, this restriction is enforced only for stored functions.) * *Note `LOAD DATA': load-data. and `LOAD TABLE'. * SQL prepared statements (*Note `PREPARE': prepare, *Note `EXECUTE': execute, *Note `DEALLOCATE PREPARE': deallocate-prepare.) can be used in stored procedures, but not stored functions or triggers. Thus, stored functions and triggers cannot use dynamic SQL (where you construct statements as strings and then execute them). * SQL statements that are not permitted within prepared statements are also not permitted in stored routines. See *Note sql-syntax-prepared-statements::, for a list of statements supported as prepared statements. Only the statements listed there are supported for stored routines, unless noted otherwise in *Note stored-routines::. * Inserts cannot be delayed. *Note `INSERT DELAYED': insert-delayed. syntax is accepted, but the statement is handled as a normal *Note `INSERT': insert. * Within all stored programs (stored procedures and functions, triggers, and events), the parser treats *Note `BEGIN [WORK]': commit. as the beginning of a *Note `BEGIN ... END': begin-end. block. To begin a transaction in this context, use *Note `START TRANSACTION': commit. instead. * Restrictions for Stored Functions * The following additional statements or operations are not permitted within stored functions. They are permitted within stored procedures, except stored procedures that are invoked from within a stored function or trigger. For example, if you use *Note `FLUSH': flush. in a stored procedure, that stored procedure cannot be called from a stored function or trigger. * Statements that perform explicit or implicit commit or rollback. Support for these statements is not required by the SQL standard, which states that each DBMS vendor may decide whether to permit them. * Statements that return a result set. This includes *Note `SELECT': select. statements that do not have an `INTO VAR_LIST' clause and other statements such as *Note `SHOW': show, *Note `EXPLAIN': explain, and *Note `CHECK TABLE': check-table. A function can process a result set either with `SELECT ... INTO VAR_LIST' or by using a cursor and *Note `FETCH': fetch. statements. See *Note select-into-statement::. * *Note `FLUSH': flush. statements. * Stored functions cannot be used recursively. * A stored function or trigger cannot modify a table that is already being used (for reading or writing) by the statement that invoked the function or trigger. * If you refer to a temporary table multiple times in a stored function under different aliases, a `Can't reopen table: 'TBL_NAME`''' error occurs, even if the references occur in different statements within the function. * Restrictions for Triggers * For triggers, the following additional restrictions apply: * Triggers currently are not activated by foreign key actions. * When using row-based replication, triggers on the slave are not activated by statements originating on the master. The triggers on the slave are activated when using statement-based replication. For more information, see *Note replication-features-triggers::. * The *Note `RETURN': return. statement is not permitted in triggers, which cannot return a value. To exit a trigger immediately, use the *Note `LEAVE': leave-statement. statement. * Triggers are not permitted on tables in the `mysql' database. * The trigger cache does not detect when metadata of the underlying objects has changed. If a trigger uses a table and the table has changed since the trigger was loaded into the cache, the trigger operates using the outdated metadata. * Restrictions on Calling Stored Procedures * Before MySQL 5.1.4, *Note `CALL': call. statements cannot be prepared, meaning that stored procedures cannot be called from dynamic SQL. This is true both for server-side prepared statements and for SQL prepared statements. * Name Conflicts within Stored Routines * The same identifier might be used for a routine parameter, a local variable, and a table column. Also, the same local variable name can be used in nested blocks. For example: CREATE PROCEDURE p (i INT) BEGIN DECLARE i INT DEFAULT 0; SELECT i FROM t; BEGIN DECLARE i INT DEFAULT 1; SELECT i FROM t; END; END; In such cases, the identifier is ambiguous and the following precedence rules apply: * A local variable takes precedence over a routine parameter or table column. * A routine parameter takes precedence over a table column. * A local variable in an inner block takes precedence over a local variable in an outer block. The behavior that variables take precedence over table columns is nonstandard. * Replication Considerations * Use of stored routines can cause replication problems. This issue is discussed further in *Note stored-programs-logging::. The `--replicate-wild-do-table=DB_NAME.TBL_NAME' option applies to tables, views, and triggers. It does not apply to stored procedures and functions, or events. To filter statements operating on the latter objects, use one or more of the `--replicate-*-db' options. * Introspection Considerations * `INFORMATION_SCHEMA' does not have a `PARAMETERS' table until MySQL 5.5; this table enables stored routines or client applications to determine the names, types, and default values of parameters for stored routines. For releases without this `INFORMATION_SCHEMA.PARAMETERS' table, to examine these types of metadata, you must use workarounds such as parsing the output of `SHOW CREATE' statements or the `param_list' column of the `mysql.proc' table. `param_list' contents can be processed from within a stored routine, unlike the output from *Note `SHOW': show. * Debugging Considerations * There are no stored routine debugging facilities. * Unsupported Syntax from the SQL:2003 Standard * The MySQL stored routine syntax is based on the SQL:2003 standard. The following items from that standard are not currently supported: * `UNDO' handlers are not supported. * `FOR' loops are not supported. * Concurrency Considerations * To prevent problems of interaction between sessions, when a client issues a statement, the server uses a snapshot of routines and triggers available for execution of the statement. That is, the server calculates a list of procedures, functions, and triggers that may be used during execution of the statement, loads them, and then proceeds to execute the statement. While the statement executes, it does not see changes to routines performed by other sessions. For maximum concurrency, stored functions should minimize their side-effects; in particular, updating a table within a stored function can reduce concurrent operations on that table. A stored function acquires table locks before executing, to avoid inconsistency in the binary log due to mismatch of the order in which statements execute and when they appear in the log. When statement-based binary logging is used, statements that invoke a function are recorded rather than the statements executed within the function. Consequently, stored functions that update the same underlying tables do not execute in parallel. In contrast, stored procedures do not acquire table-level locks. All statements executed within stored procedures are written to the binary log, even for statement-based binary logging. See *Note stored-programs-logging::. * Event Scheduler Restrictions * The following limitations are specific to the Event Scheduler: * In MySQL 5.1.6 only, any table referenced in an event's action statement must be fully qualified with the name of the schema in which it occurs (that is, as `SCHEMA_NAME.TABLE_NAME'). * Beginning with MySQL 5.1.8, event names are handled in case-insensitive fashion. For example, this means that you cannot have two events in the same database (and--prior to MySQL 5.1.12--with the same definer) with the names `anEvent' and `AnEvent'. *Important*: If you have events created in MySQL 5.1.7 or earlier which are assigned to the same database and have the same definer, and whose names differ only with respect to lettercase, then you must rename these events to respect case-sensitive handling before upgrading to MySQL 5.1.8 or later. * An event may not be created, altered, or dropped by a stored routine, trigger, or another event. An event also may not create, alter, or drop stored routines or triggers. (Bug#16409, Bug#18896) * Event timings using the intervals `YEAR', `QUARTER', `MONTH', and `YEAR_MONTH' are resolved in months; those using any other interval are resolved in seconds. There is no way to cause events scheduled to occur at the same second to execute in a given order. In addition--due to rounding, the nature of threaded applications, and the fact that a nonzero length of time is required to create events and to signal their execution--events may be delayed by as much as 1 or 2 seconds. However, the time shown in the *Note `INFORMATION_SCHEMA.EVENTS': events-table. table's `LAST_EXECUTED' column or the `mysql.event' table's `last_executed' column is always accurate to within one second of the actual event execution time. (See also Bug#16522.) * Each execution of the statements contained in the body of an event takes place in a new connection; thus, these statements has no effect in a given user session on the server's statement counts such as `Com_select' and `Com_insert' that are displayed by *Note `SHOW STATUS': show-status. However, such counts _are_ updated in the global scope. (Bug#16422) * Prior to MySQL 5.1.12, you could not view another user's events in the *Note `INFORMATION_SCHEMA.EVENTS': events-table. table. In other words, any query made against this table was treated as though it contained the condition `DEFINER = CURRENT_USER()' in the `WHERE' clause. * Events do not support times later than the end of the Unix Epoch; this is approximately the beginning of the year 2038. Prior to MySQL 5.1.8, handling in scheduled events of dates later than this was buggy; starting with MySQL 5.1.8, such dates are specifically not permitted by the Event Scheduler. (Bug#16396) * In MySQL 5.1.6, *Note `INFORMATION_SCHEMA.EVENTS': events-table. shows `NULL' in the `SQL_MODE' column. Beginning with MySQL 5.1.7, the `SQL_MODE' displayed is that in effect when the event was created. * In MySQL 5.1.6, the only way to drop or alter an event created by a user who was not the definer of that event was by manipulation of the `mysql.event' system table by the MySQL `root' user or by another user with privileges on this table. Beginning with MySQL 5.1.7, *Note `DROP USER': drop-user. drops all events for which that user was the definer; also beginning with MySQL 5.1.7 *Note `DROP SCHEMA': drop-database. drops all events associated with the dropped schema. * References to stored functions, user-defined functions, and tables in the `ON SCHEDULE' clauses of *Note `CREATE EVENT': create-event. and *Note `ALTER EVENT': alter-event. statements are not supported. Beginning with MySQL 5.1.13, these sorts of references are not permitted. (See Bug#22830 for more information.) * Generally speaking, statements that are not permitted in stored routines or in SQL prepared statements are also not permitted in the body of an event. For more information, see *Note sql-syntax-prepared-statements::. * When upgrading to MySQL 5.1.18 or 5.1.19 from a previous MySQL version where scheduled events were in use, the upgrade utilities *Note `mysql_upgrade': mysql-upgrade. and *Note `mysql_fix_privilege_tables': mysql-fix-privilege-tables. do not accommodate changes in system tables relating to the Event Scheduler. This issue was fixed in MySQL 5.1.20 (see Bug#28521). Stored routines and triggers in MySQL Cluster Stored procedures, stored functions, and triggers are all supported by tables using the *Note `NDB': mysql-cluster. storage engine; however, it is important to keep in mind that they do _not_ propagate automatically between MySQL Servers acting as Cluster SQL nodes. This is because of the following: * Stored routine definitions are kept in tables in the `mysql' system database using the `MyISAM' storage engine, and so do not participate in clustering. * The `.TRN' and `.TRG' files containing trigger definitions are not read by the *Note `NDB': mysql-cluster. storage engine, and are not copied between Cluster nodes. Any stored routine or trigger that interacts with MySQL Cluster tables must be re-created by running the appropriate *Note `CREATE PROCEDURE': create-procedure, *Note `CREATE FUNCTION': create-function, or *Note `CREATE TRIGGER': create-trigger. statements on each MySQL Server that participates in the cluster where you wish to use the stored routine or trigger. Similarly, any changes to existing stored routines or triggers must be carried out explicitly on all Cluster SQL nodes, using the appropriate `ALTER' or `DROP' statements on each MySQL Server accessing the cluster. *Warning*: Do _not_ attempt to work around the issue described in the first item mentioned previously by converting any `mysql' database tables to use the *Note `NDB': mysql-cluster. storage engine. _Altering the system tables in the `mysql' database is not supported_ and is very likely to produce undesirable results.  File: manual.info, Node: cursor-restrictions, Next: subquery-restrictions, Prev: stored-program-restrictions, Up: restrictions E.2 Restrictions on Server-Side Cursors ======================================= Server-side cursors are implemented in the C API using the *Note `mysql_stmt_attr_set()': mysql-stmt-attr-set. function. The same implementation is used for cursors in stored routines. A server-side cursor enables a result set to be generated on the server side, but not transferred to the client except for those rows that the client requests. For example, if a client executes a query but is only interested in the first row, the remaining rows are not transferred. In MySQL, a server-side cursor is materialized into a temporary table. Initially, this is a `MEMORY' table, but is converted to a `MyISAM' table if its size reaches the value of the `max_heap_table_size' system variable. One limitation of the implementation is that for a large result set, retrieving its rows through a cursor might be slow. Cursors are read only; you cannot use a cursor to update rows. `UPDATE WHERE CURRENT OF' and `DELETE WHERE CURRENT OF' are not implemented, because updatable cursors are not supported. Cursors are nonholdable (not held open after a commit). Cursors are asensitive. Cursors are nonscrollable. Cursors are not named. The statement handler acts as the cursor ID. You can have open only a single cursor per prepared statement. If you need several cursors, you must prepare several statements. You cannot use a cursor for a statement that generates a result set if the statement is not supported in prepared mode. This includes statements such as *Note `CHECK TABLE': check-table, `HANDLER READ', and *Note `SHOW BINLOG EVENTS': show-binlog-events.  File: manual.info, Node: subquery-restrictions, Next: view-restrictions, Prev: cursor-restrictions, Up: restrictions E.3 Restrictions on Subqueries ============================== * In MySQL 5.1 before 5.1.16, if you compare a `NULL' value to a subquery using `ALL', `ANY', or `SOME', and the subquery returns an empty result, the comparison might evaluate to the nonstandard result of `NULL' rather than to `TRUE' or `FALSE'. As of 5.1.16, the comparison evaluates to `TRUE' or `FALSE' except for subqueries inside `IS NULL', such as this: SELECT ... WHERE NULL IN (SELECT ...) IS NULL As of 5.1.32, the `IS NULL' limitation is removed and the comparison evaluates to `TRUE' or `FALSE'. * A subquery's outer statement can be any one of: *Note `SELECT': select, *Note `INSERT': insert, *Note `UPDATE': update, *Note `DELETE': delete, *Note `SET': set-option, or *Note `DO': do. * Subquery optimization for `IN' is not as effective as for the `=' operator or for the `IN(VALUE_LIST)' operator. A typical case for poor `IN' subquery performance is when the subquery returns a small number of rows but the outer query returns a large number of rows to be compared to the subquery result. The problem is that, for a statement that uses an `IN' subquery, the optimizer rewrites it as a correlated subquery. Consider the following statement that uses an uncorrelated subquery: SELECT ... FROM t1 WHERE t1.a IN (SELECT b FROM t2); The optimizer rewrites the statement to a correlated subquery: SELECT ... FROM t1 WHERE EXISTS (SELECT 1 FROM t2 WHERE t2.b = t1.a); If the inner and outer queries return M and N rows, respectively, the execution time becomes on the order of O(MxN), rather than O(M+N) as it would be for an uncorrelated subquery. An implication is that an `IN' subquery can be much slower than a query written using an `IN(VALUE_LIST)' operator that lists the same values that the subquery would return. * In general, you cannot modify a table and select from the same table in a subquery. For example, this limitation applies to statements of the following forms: DELETE FROM t WHERE ... (SELECT ... FROM t ...); UPDATE t ... WHERE col = (SELECT ... FROM t ...); {INSERT|REPLACE} INTO t (SELECT ... FROM t ...); Exception: The preceding prohibition does not apply if you are using a subquery for the modified table in the `FROM' clause. Example: UPDATE t ... WHERE col = (SELECT * FROM (SELECT ... FROM t...) AS _t ...); Here the result from the subquery in the `FROM' clause is stored as a temporary table, so the relevant rows in `t' have already been selected by the time the update to `t' takes place. * Row comparison operations are only partially supported: * For `EXPR IN (SUBQUERY)', EXPR can be an N-tuple (specified using row constructor syntax) and the subquery can return rows of N-tuples. * For `EXPR OP {ALL|ANY|SOME} (SUBQUERY)', EXPR must be a scalar value and the subquery must be a column subquery; it cannot return multiple-column rows. In other words, for a subquery that returns rows of N-tuples, this is supported: (VAL_1, ..., VAL_N) IN (SUBQUERY) But this is not supported: (VAL_1, ..., VAL_N) OP {ALL|ANY|SOME} (SUBQUERY) The reason for supporting row comparisons for `IN' but not for the others is that `IN' is implemented by rewriting it as a sequence of `=' comparisons and `AND' operations. This approach cannot be used for `ALL', `ANY', or `SOME'. * Prior to MySQL 5.1.12, row constructors were not well optimized; of the following two equivalent expressions, only the second could be optimized: (col1, col2, ...) = (val1, val2, ...) col1 = val1 AND col2 = val2 AND ... In MySQL 5.1.12 and later, all row equalities are converted into conjunctions of equalities between row elements, and handled by the optimizer in the same way. (Bug#16081) * Subqueries in the `FROM' clause cannot be correlated subqueries. They are materialized (executed to produce a result set) before evaluating the outer query, so they cannot be evaluated per row of the outer query. * MySQL does not support `LIMIT' in subqueries for certain subquery operators: mysql> SELECT * FROM t1 -> WHERE s1 IN (SELECT s2 FROM t2 ORDER BY s1 LIMIT 1); ERROR 1235 (42000): This version of MySQL doesn't yet support 'LIMIT & IN/ALL/ANY/SOME subquery' * The optimizer is more mature for joins than for subqueries, so in many cases a statement that uses a subquery can be executed more efficiently if you rewrite it as a join. An exception occurs for the case where an `IN' subquery can be rewritten as a *Note `SELECT DISTINCT': select. join. Example: SELECT col FROM t1 WHERE id_col IN (SELECT id_col2 FROM t2 WHERE CONDITION); That statement can be rewritten as follows: SELECT DISTINCT col FROM t1, t2 WHERE t1.id_col = t2.id_col AND CONDITION; But in this case, the join requires an extra `DISTINCT' operation and is not more efficient than the subquery. * MySQL permits a subquery to refer to a stored function that has data-modifying side effects such as inserting rows into a table. For example, if `f()' inserts rows, the following query can modify data: SELECT ... WHERE x IN (SELECT f() ...); This behavior is nonstandard (not permitted by the SQL standard). In MySQL, it can produce indeterminate results because `f()' might be executed a different number of times for different executions of a given query depending on how the optimizer chooses to handle it. For statement-based or mixed-format replication, one implication of this indeterminism is that such a query can produce different results on the master and its slaves. * Possible future optimization: MySQL does not rewrite the join order for subquery evaluation. In some cases, a subquery could be executed more efficiently if MySQL rewrote it as a join. This would give the optimizer a chance to choose between more execution plans. For example, it could decide whether to read one table or the other first. Example: SELECT a FROM outer_table AS ot WHERE a IN (SELECT a FROM inner_table AS it WHERE ot.b = it.b); For that query, MySQL always scans `outer_table' first and then executes the subquery on `inner_table' for each row. If `outer_table' has a lot of rows and `inner_table' has few rows, the query probably will not be as fast as it could be. The preceding query could be rewritten like this: SELECT a FROM outer_table AS ot, inner_table AS it WHERE ot.a = it.a AND ot.b = it.b; In this case, we can scan the small table (`inner_table') and look up rows in `outer_table', which will be fast if there is an index on `(ot.a,ot.b)'. * Possible future optimization: A correlated subquery is evaluated for each row of the outer query. A better approach is that if the outer row values do not change from the previous row, do not evaluate the subquery again. Instead, use its previous result. * Possible future optimization: A subquery in the `FROM' clause is evaluated by materializing the result into a temporary table, and this table does not use indexes. This does not allow the use of indexes in comparison with other tables in the query, although that might be useful. * Possible future optimization: If a subquery in the `FROM' clause resembles a view to which the merge algorithm can be applied, rewrite the query and apply the merge algorithm so that indexes can be used. The following statement contains such a subquery: SELECT * FROM (SELECT * FROM t1 WHERE t1.t1_col) AS _t1, t2 WHERE t2.t2_col; The statement can be rewritten as a join like this: SELECT * FROM t1, t2 WHERE t1.t1_col AND t2.t2_col; This type of rewriting would provide two benefits: * It avoids the use of a temporary table for which no indexes can be used. In the rewritten query, the optimizer can use indexes on `t1'. * It gives the optimizer more freedom to choose between different execution plans. For example, rewriting the query as a join enables the optimizer to use `t1' or `t2' first. * Possible future optimization: For `IN', `= ANY', `<> ANY', `= ALL', and `<> ALL' with uncorrelated subqueries, use an in-memory hash for a result or a temporary table with an index for larger results. Example: SELECT a FROM big_table AS bt WHERE non_key_field IN (SELECT non_key_field FROM TABLE WHERE CONDITION) In this case, we could create a temporary table: CREATE TABLE t (key (non_key_field)) (SELECT non_key_field FROM TABLE WHERE CONDITION) Then, for each row in `big_table', do a key lookup in `t' based on `bt.non_key_field'.  File: manual.info, Node: view-restrictions, Next: xa-restrictions, Prev: subquery-restrictions, Up: restrictions E.4 Restrictions on Views ========================= View processing is not optimized: * It is not possible to create an index on a view. * Indexes can be used for views processed using the merge algorithm. However, a view that is processed with the temptable algorithm is unable to take advantage of indexes on its underlying tables (although indexes can be used during generation of the temporary tables). Subqueries cannot be used in the `FROM' clause of a view. There is a general principle that you cannot modify a table and select from the same table in a subquery. See *Note subquery-restrictions::. The same principle also applies if you select from a view that selects from the table, if the view selects from the table in a subquery and the view is evaluated using the merge algorithm. Example: CREATE VIEW v1 AS SELECT * FROM t2 WHERE EXISTS (SELECT 1 FROM t1 WHERE t1.a = t2.a); UPDATE t1, v2 SET t1.a = 1 WHERE t1.b = v2.b; If the view is evaluated using a temporary table, you _can_ select from the table in the view subquery and still modify that table in the outer query. In this case the view will be stored in a temporary table and thus you are not really selecting from the table in a subquery and modifying it `at the same time.' (This is another reason you might wish to force MySQL to use the temptable algorithm by specifying `ALGORITHM = TEMPTABLE' in the view definition.) You can use *Note `DROP TABLE': drop-table. or *Note `ALTER TABLE': alter-table. to drop or alter a table that is used in a view definition. No warning results from the `DROP' or `ALTER' operation, even though this invalidates the view. Instead, an error occurs later, when the view is used. *Note `CHECK TABLE': check-table. can be used to check for views that have been invalidated by `DROP' or `ALTER' operations. A view definition is `frozen' by certain statements: * If a statement prepared by *Note `PREPARE': prepare. refers to a view, the view definition seen each time the statement is executed later will be the definition of the view at the time it was prepared. This is true even if the view definition is changed after the statement is prepared and before it is executed. Example: CREATE VIEW v AS SELECT RAND(); PREPARE s FROM 'SELECT * FROM v'; ALTER VIEW v AS SELECT NOW(); EXECUTE s; The result returned by the *Note `EXECUTE': execute. statement is a random number, not the current date and time. * If a statement in a stored routine refers to a view, the view definition seen by the statement are its definition the first time that statement is executed. For example, this means that if the statement is executed in a loop, further iterations of the statement see the same view definition, even if the definition is changed later in the loop. Example: CREATE VIEW v AS SELECT 1; delimiter // CREATE PROCEDURE p () BEGIN DECLARE i INT DEFAULT 0; WHILE i < 5 DO SELECT * FROM v; SET i = i + 1; ALTER VIEW v AS SELECT 2; END WHILE; END; // delimiter ; CALL p(); When the procedure `p()' is called, the *Note `SELECT': select. returns 1 each time through the loop, even though the view definition is changed within the loop. As of MySQL 5.1.21, *Note `ALTER VIEW': alter-view. is prohibited within stored routines, so this restriction does not apply. With regard to view updatability, the overall goal for views is that if any view is theoretically updatable, it should be updatable in practice. This includes views that have *Note `UNION': union. in their definition. Currently, not all views that are theoretically updatable can be updated. The initial view implementation was deliberately written this way to get usable, updatable views into MySQL as quickly as possible. Many theoretically updatable views can be updated now, but limitations still exist: * Updatable views with subqueries anywhere other than in the `WHERE' clause. Some views that have subqueries in the *Note `SELECT': select. list may be updatable. * You cannot use *Note `UPDATE': update. to update more than one underlying table of a view that is defined as a join. * You cannot use *Note `DELETE': delete. to update a view that is defined as a join. There exists a shortcoming with the current implementation of views. If a user is granted the basic privileges necessary to create a view (the `CREATE VIEW' and `SELECT' privileges), that user will be unable to call *Note `SHOW CREATE VIEW': show-create-view. on that object unless the user is also granted the `SHOW VIEW' privilege. That shortcoming can lead to problems backing up a database with *Note `mysqldump': mysqldump, which may fail due to insufficient privileges. This problem is described in Bug#22062. The workaround to the problem is for the administrator to manually grant the `SHOW VIEW' privilege to users who are granted `CREATE VIEW', since MySQL doesn't grant it implicitly when views are created. Views do not have indexes, so index hints do not apply. Use of index hints when selecting from a view is not permitted. *Note `SHOW CREATE VIEW': show-create-view. displays view definitions using an `AS ALIAS_NAME' clause for each column. If a column is created from an expression, the default alias is the expression text, which can be quite long. As of MySQL 5.1.23, aliases for column names in *Note `CREATE VIEW': create-view. statements are checked against the maximum column length of 64 characters (not the maximum alias length of 256 characters). As a result, views created from the output of *Note `SHOW CREATE VIEW': show-create-view. fail if any column alias exceeds 64 characters. This can cause problems in the following circumstances for views with too-long aliases: * View definitions fail to replicate to newer slaves that enforce the column-length restriction. * Dump files created with *Note `mysqldump': mysqldump. cannot be loaded into servers that enforce the column-length restriction. A workaround for either problem is the modify each problematic view definition to use aliases that provide shorter column names. Then the view will replicate properly, and can be dumped and reloaded without causing an error. To modify the definition, drop and create the view again with *Note `DROP VIEW': drop-view. and *Note `CREATE VIEW': create-view, or replace the definition with *Note `CREATE OR REPLACE VIEW': create-view. For problems that occur when reloading view definitions in dump files, another workaround is to edit the dump file to modify its *Note `CREATE VIEW': create-view. statements. However, this does not change the original view definitions, which may cause problems for subsequent dump operations.  File: manual.info, Node: xa-restrictions, Next: charset-restrictions, Prev: view-restrictions, Up: restrictions E.5 Restrictions on XA Transactions =================================== XA transaction support is limited to the `InnoDB' storage engine. For `external XA,' a MySQL server acts as a Resource Manager and client programs act as Transaction Managers. For `Internal XA', storage engines within a MySQL server act as RMs, and the server itself acts as a TM. Internal XA support is limited by the capabilities of individual storage engines. Internal XA is required for handling XA transactions that involve more than one storage engine. The implementation of internal XA requires that a storage engine support two-phase commit at the table handler level, and currently this is true only for `InnoDB'. For *Note `XA START': xa-statements, the `JOIN' and `RESUME' clauses are not supported. For *Note `XA END': xa-statements, the `SUSPEND [FOR MIGRATE]' clause is not supported. The requirement that the BQUAL part of the XID value be different for each XA transaction within a global transaction is a limitation of the current MySQL XA implementation. It is not part of the XA specification. If an XA transaction has reached the `PREPARED' state and the MySQL server is killed (for example, with *Note `kill -9': kill. on Unix) or shuts down abnormally, the transaction can be continued after the server restarts. However, if the client reconnects and commits the transaction, the transaction will be absent from the binary log even though it has been committed. This means the data and the binary log have gone out of synchrony. An implication is that XA cannot be used safely together with replication. It is possible that the server will roll back a pending XA transaction, even one that has reached the `PREPARED' state. This happens if a client connection terminates and the server continues to run, or if clients are connected and the server shuts down gracefully. (In the latter case, the server marks each connection to be terminated, and then rolls back the `PREPARED' XA transaction associated with it.) It should be possible to commit or roll back a `PREPARED' XA transaction, but this cannot be done without changes to the binary logging mechanism.  File: manual.info, Node: charset-restrictions, Next: limits, Prev: xa-restrictions, Up: restrictions E.6 Restrictions on Character Sets ================================== * Identifiers are stored in `mysql' database tables (`user', `db', and so forth) using `utf8', but identifiers can contain only characters in the Basic Multilingual Plane (BMP). Supplementary characters are not permitted in identifiers. * The `ucs2' character sets has the following restrictions: * It cannot be used as a client character set, which means that it does not work for `SET NAMES' or `SET CHARACTER SET'. (See *Note charset-connection::.) * It is currently not possible to use *Note `LOAD DATA INFILE': load-data. to load data files that use this character set. * `FULLTEXT' indexes cannot be created on a column that this character set. However, you can perform `IN BOOLEAN MODE' searches on the column without an index. * The use of `ENCRYPT()' with this character set is not recommended because the underlying system call expects a string terminated by a zero byte. * The `REGEXP' and `RLIKE' operators work in byte-wise fashion, so they are not multi-byte safe and may produce unexpected results with multi-byte character sets. In addition, these operators compare characters by their byte values and accented characters may not compare as equal even if a given collation treats them as equal.  File: manual.info, Node: limits, Prev: charset-restrictions, Up: restrictions E.7 Limits in MySQL =================== * Menu: * joins-limits:: Limits of Joins * database-count-limit:: Limits on Number of Databases and Tables * table-size-limit:: Limits on Table Size * column-count-limit:: Table Column-Count and Row-Size Limits * limits-windows:: Windows Platform Limitations This section lists current limits in MySQL 5.1.  File: manual.info, Node: joins-limits, Next: database-count-limit, Prev: limits, Up: limits E.7.1 Limits of Joins --------------------- The maximum number of tables that can be referenced in a single join is 61. This also applies to the number of tables that can be referenced in the definition of a view.  File: manual.info, Node: database-count-limit, Next: table-size-limit, Prev: joins-limits, Up: limits E.7.2 Limits on Number of Databases and Tables ---------------------------------------------- MySQL has no limit on the number of databases. The underlying file system may have a limit on the number of directories. MySQL has no limit on the number of databases. The underlying file system may have a limit on the number of tables. Individual storage engines may impose engine-specific constraints. `InnoDB' permits up to 4 billion tables.  File: manual.info, Node: table-size-limit, Next: column-count-limit, Prev: database-count-limit, Up: limits E.7.3 Limits on Table Size -------------------------- The effective maximum table size for MySQL databases is usually determined by operating system constraints on file sizes, not by MySQL internal limits. The following table lists some examples of operating system file-size limits. This is only a rough guide and is not intended to be definitive. For the most up-to-date information, be sure to check the documentation specific to your operating system. Operating System File-size Limit Win32 w/ FAT/FAT32 2GB/4GB Win32 w/ NTFS 2TB (possibly larger) Linux 2.2-Intel 32-bit 2GB (LFS: 4GB) Linux 2.4+ (using ext3 file system) 4TB Solaris 9/10 16TB MacOS X w/ HFS+ 2TB NetWare w/NSS file 8TB system Windows users, please note that FAT and VFAT (FAT32) are _not_ considered suitable for production use with MySQL. Use NTFS instead. On Linux 2.2, you can get `MyISAM' tables larger than 2GB in size by using the Large File Support (LFS) patch for the ext2 file system. Most current Linux distributions are based on kernel 2.4 or higher and include all the required LFS patches. On Linux 2.4, patches also exist for ReiserFS to get support for big files (up to 2TB). With JFS and XFS, petabyte and larger files are possible on Linux. For a detailed overview about LFS in Linux, have a look at Andreas Jaeger's `Large File Support in Linux' page at `http://www.suse.de/~aj/linux_lfs.html'. If you do encounter a full-table error, there are several reasons why it might have occurred: * The disk might be full. * The `InnoDB' storage engine maintains `InnoDB' tables within a tablespace that can be created from several files. This enables a table to exceed the maximum individual file size. The tablespace can include raw disk partitions, which permits extremely large tables. The maximum tablespace size is 64TB. If you are using `InnoDB' tables and run out of room in the `InnoDB' tablespace. In this case, the solution is to extend the `InnoDB' tablespace. See *Note innodb-data-log-reconfiguration::. * You are using `MyISAM' tables on an operating system that supports files only up to 2GB in size and you have hit this limit for the data file or index file. * You are using a `MyISAM' table and the space required for the table exceeds what is permitted by the internal pointer size. `MyISAM' permits data and index files to grow up to 256TB by default, but this limit can be changed up to the maximum permissible size of 65,536TB (256^7 - 1 bytes). If you need a `MyISAM' table that is larger than the default limit and your operating system supports large files, the *Note `CREATE TABLE': create-table. statement supports `AVG_ROW_LENGTH' and `MAX_ROWS' options. See *Note create-table::. The server uses these options to determine how large a table to permit. If the pointer size is too small for an existing table, you can change the options with *Note `ALTER TABLE': alter-table. to increase a table's maximum permissible size. See *Note alter-table::. ALTER TABLE TBL_NAME MAX_ROWS=1000000000 AVG_ROW_LENGTH=NNN; You have to specify `AVG_ROW_LENGTH' only for tables with *Note `BLOB': blob. or *Note `TEXT': blob. columns; in this case, MySQL can't optimize the space required based only on the number of rows. To change the default size limit for `MyISAM' tables, set the `myisam_data_pointer_size', which sets the number of bytes used for internal row pointers. The value is used to set the pointer size for new tables if you do not specify the `MAX_ROWS' option. The value of `myisam_data_pointer_size' can be from 2 to 7. A value of 4 permits tables up to 4GB; a value of 6 permits tables up to 256TB. You can check the maximum data and index sizes by using this statement: SHOW TABLE STATUS FROM DB_NAME LIKE 'TBL_NAME'; You also can use *Note `myisamchk -dv /path/to/table-index-file': myisamchk. See *Note show::, or *Note myisamchk::. Other ways to work around file-size limits for `MyISAM' tables are as follows: * If your large table is read only, you can use *Note `myisampack': myisampack. to compress it. *Note `myisampack': myisampack. usually compresses a table by at least 50%, so you can have, in effect, much bigger tables. *Note `myisampack': myisampack. also can merge multiple tables into a single table. See *Note myisampack::. * MySQL includes a `MERGE' library that enables you to handle a collection of `MyISAM' tables that have identical structure as a single `MERGE' table. See *Note merge-storage-engine::. * You are using the *Note `NDB': mysql-cluster. storage engine, in which case you need to increase the values for the `DataMemory' and `IndexMemory' configuration parameters in your `config.ini' file. See *Note mysql-cluster-params-ndbd::. * You are using the `MEMORY' (`HEAP') storage engine; in this case you need to increase the value of the `max_heap_table_size' system variable. See *Note server-system-variables::.  File: manual.info, Node: column-count-limit, Next: limits-windows, Prev: table-size-limit, Up: limits E.7.4 Table Column-Count and Row-Size Limits -------------------------------------------- There is a hard limit of 4096 columns per table, but the effective maximum may be less for a given table. The exact limit depends on several interacting factors. * Every table (regardless of storage engine) has a maximum row size of 65,535 bytes. Storage engines may place additional constraints on this limit, reducing the effective maximum row size. The maximum row size constrains the number (and possibly size) of columns because the total length of all columns cannot exceed this size. For example, `utf8' characters require up to three bytes per character, so for a *Note `CHAR(255) CHARACTER SET utf8': char. column, the server must allocate 255 x 3 = 765 bytes per value. Consequently, a table cannot contain more than 65,535 / 765 = 85 such columns. Storage for variable-length columns includes length bytes, which are assessed against the row size. For example, a *Note `VARCHAR(255) CHARACTER SET utf8': char. column takes two bytes to store the length of the value, so each value can take up to 767 bytes. *Note `BLOB': blob. and *Note `TEXT': blob. columns count from one to four plus eight bytes each toward the row-size limit because their contents are stored separately from the rest of the row. Declaring columns `NULL' can reduce the maximum number of columns permitted. For *Note `MyISAM': myisam-storage-engine. tables, `NULL' columns require additional space in the row to record whether their values are `NULL'. Each `NULL' column takes one bit extra, rounded up to the nearest byte. The maximum row length in bytes can be calculated as follows: row length = 1 + (SUM OF COLUMN LENGTHS) + (NUMBER OF NULL COLUMNS + DELETE_FLAG + 7)/8 + (NUMBER OF VARIABLE-LENGTH COLUMNS) DELETE_FLAG is 1 for tables with static row format. Static tables use a bit in the row record for a flag that indicates whether the row has been deleted. DELETE_FLAG is 0 for dynamic tables because the flag is stored in the dynamic row header. For information about *Note `MyISAM': myisam-storage-engine. table formats, see *Note myisam-table-formats::. These calculations do not apply for *Note `InnoDB': innodb-storage-engine. tables. Storage size is the same for `NULL' and `NOT NULL' columns. The following statement to create table `t1' succeeds because the columns require 32,765 + 2 bytes and 32,766 + 2 bytes, which falls within the maximum row size of 65,535 bytes: mysql> CREATE TABLE t1 -> (c1 VARCHAR(32765) NOT NULL, c2 VARCHAR(32766) NOT NULL) -> ENGINE = MyISAM CHARACTER SET latin1; Query OK, 0 rows affected (0.02 sec) The following statement to create table `t2' fails because the columns are `NULL' and *Note `MyISAM': myisam-storage-engine. requires additional space that causes the row size to exceed 65,535 bytes: mysql> CREATE TABLE t2 -> (c1 VARCHAR(32765) NULL, c2 VARCHAR(32766) NULL) -> ENGINE = MyISAM CHARACTER SET latin1; ERROR 1118 (42000): Row size too large. The maximum row size for the used table type, not counting BLOBs, is 65535. You have to change some columns to TEXT or BLOBs The following statement to create table `t3' fails because although the column length is within the maximum length of 65,535 bytes, two additional bytes are required to record the length, which causes the row size to exceed 65,535 bytes: mysql> CREATE TABLE t3 -> (c1 VARCHAR(65535) NOT NULL) -> ENGINE = MyISAM CHARACTER SET latin1; ERROR 1118 (42000): Row size too large. The maximum row size for the used table type, not counting BLOBs, is 65535. You have to change some columns to TEXT or BLOBs Reducing the column length to 65,533 or less permits the statement to succeed. * Each table has an `.frm' file that contains the table definition. The server uses the following expression to check some of the table information stored in the file against an upper limit of 64KB: if (info_length+(ulong) create_fields.elements*FCOMP+288+ n_length+int_length+com_length > 65535L || int_count > 255) The portion of the information stored in the `.frm' file that is checked against the expression cannot grow beyond the 64KB limit, so if the table definition reaches this size, no more columns can be added. The relevant factors in the expression are: * `info_length' is space needed for `screens.' This is related to MySQL's Unireg heritage. * `create_fields.elements' is the number of columns. * `FCOMP' is 17. * `n_length' is the total length of all column names, including one byte per name as a separator. * `int_length' is related to the list of values for *Note `ENUM': enum. and *Note `SET': set. columns. * `com_length' is the total length of column and table comments. Thus, using long column names can reduce the maximum number of columns, as can the inclusion of *Note `ENUM': enum. or *Note `SET': set. columns, or use of column or table comments. * Individual storage engines might impose additional restrictions that limit table column count. Examples: * *Note `InnoDB': innodb-storage-engine. permits no more than 1000 columns. * *Note `InnoDB': innodb-storage-engine. restricts row size to something less than half a database page (approximately 8000 bytes), not including *Note `VARBINARY': binary-varbinary, *Note `VARCHAR': char, *Note `BLOB': blob, or *Note `TEXT': blob. columns. * Different *Note `InnoDB': innodb-storage-engine. storage formats (`COMPRESSED', `REDUNDANT') use different amounts of page header and trailer data, which affects the amount of storage available for rows.  File: manual.info, Node: limits-windows, Prev: column-count-limit, Up: limits E.7.5 Windows Platform Limitations ---------------------------------- The following limitations apply to use of MySQL on the Windows platform: * *Number of file descriptors* The number of open file descriptors on Windows is limited to a maximum of 2048, which may limit the ability to open a large number of tables simultaneously. This limit is due not to Windows but to C runtime library compatibility functions used to open files on Windows that use the POSIX compatibility layer. This limitation will also cause problems if you try to set `open_files_limit' to a value greater than the 2048 file limit. * *Process memory* On Windows 32-bit platforms it is not possible by default to use more than 2GB of RAM within a single process, including MySQL. This is because the physical address limit on Windows 32-bit is 4GB and the default setting within Windows is to split the virtual address space between kernel (2GB) and user/applications (2GB). Some versions of Windows have a boot time setting to enable larger applications by reducing the kernel application. Alternatively, to use more than 2GB, use a 64-bit version of Windows. * *File system aliases* When using `MyISAM' tables, you cannot use aliases within Windows link to the data files on another volume and then link back to the main MySQL `datadir' location. This facility is often used to move the data and index files to a RAID or other fast solution, while retaining the main `.frm' files in the default data directory configured with the `datadir' option. * *Limited number of ports* Windows systems have about 4,000 ports available for client connections, and after a connection on a port closes, it takes two to four minutes before the port can be reused. In situations where clients connect to and disconnect from the server at a high rate, it is possible for all available ports to be used up before closed ports become available again. If this happens, the MySQL server appears to be unresponsive even though it is running. Note that ports may be used by other applications running on the machine as well, in which case the number of ports available to MySQL is lower. For more information about this problem, see `http://support.microsoft.com/default.aspx?scid=kb;en-us;196271'. * *Concurrent reads* MySQL depends on the `pread()' and `pwrite()' system calls to be able to mix *Note `INSERT': insert. and *Note `SELECT': select. Currently, we use mutexes to emulate `pread()' and `pwrite()'. We intend to replace the file level interface with a virtual interface in the future so that we can use the `readfile()'/`writefile()' interface to get more speed. The current implementation limits the number of open files that MySQL 5.1 can use to 2,048, which means that you cannot run as many concurrent threads on Windows as on Unix. This problem is fixed in MySQL 5.5. * *Blocking read* Before MySQL 5.1.41, MySQL uses a blocking read for each connection. That has the following implications if named-pipe connections are enabled: * A connection is not disconnected automatically after eight hours, as happens with the Unix version of MySQL. * If a connection hangs, it is not possible to break it without killing MySQL. * *Note `mysqladmin kill': mysqladmin. does not work on a sleeping connection. * *Note `mysqladmin shutdown': mysqladmin. cannot abort as long as there are sleeping connections. * **Note `DROP DATABASE': drop-database.* You cannot drop a database that is in use by another session. * *Case-insensitive names* File names are not case sensitive on Windows, so MySQL database and table names are also not case sensitive on Windows. The only restriction is that database and table names must be specified using the same case throughout a given statement. See *Note identifier-case-sensitivity::. * *Directory and file names* On Windows, MySQL Server supports only directory and file names that are compatible with the current ANSI code pages. For example, the following Japanese directory name will not work in the Western locale (code page 1252): datadir="C:/私たちのプロジェクトのデータ" The same limitation applies to directory and file names referred to in SQL statements, such as the data file path name in *Note `LOAD DATA INFILE': load-data. * *The ``\'' path name separator character* Path name components in Windows are separated by the ``\'' character, which is also the escape character in MySQL. If you are using *Note `LOAD DATA INFILE': load-data. or *Note `SELECT ... INTO OUTFILE': select, use Unix-style file names with ``/'' characters: mysql> LOAD DATA INFILE 'C:/tmp/skr.txt' INTO TABLE skr; mysql> SELECT * INTO OUTFILE 'C:/tmp/skr.txt' FROM skr; Alternatively, you must double the ``\'' character: mysql> LOAD DATA INFILE 'C:\\tmp\\skr.txt' INTO TABLE skr; mysql> SELECT * INTO OUTFILE 'C:\\tmp\\skr.txt' FROM skr; * *Problems with pipes* Pipes do not work reliably from the Windows command-line prompt. If the pipe includes the character `^Z' / `CHAR(24)', Windows thinks that it has encountered end-of-file and aborts the program. This is mainly a problem when you try to apply a binary log as follows: C:\> mysqlbinlog BINARY_LOG_FILE | mysql --user=root If you have a problem applying the log and suspect that it is because of a `^Z' / `CHAR(24)' character, you can use the following workaround: C:\> mysqlbinlog BINARY_LOG_FILE --result-file=/tmp/bin.sql C:\> mysql --user=root --execute "source /tmp/bin.sql" The latter command also can be used to reliably read in any SQL file that may contain binary data. [index] * Menu: * ! (logical NOT): logical-operators. (line 29) * != (not equal): comparison-operators. (line 91) * ": identifiers. (line 20) * #mysql50 identifier prefix <1>: identifier-mapping. (line 83) * #mysql50 identifier prefix: identifiers. (line 108) * %: arithmetic-functions. (line 118) * % (modulo): mathematical-functions. (line 303) * % (wildcard character): string-syntax. (line 65) * & (bitwise AND): bit-functions. (line 29) * && (logical AND): logical-operators. (line 48) * () (parentheses): operator-precedence. (line 48) * (Control+Z) \Z <1>: load-data. (line 432) * (Control+Z) \Z: string-syntax. (line 63) * * (multiplication): arithmetic-functions. (line 83) * + (addition): arithmetic-functions. (line 55) * - (subtraction): arithmetic-functions. (line 62) * - (unary minus): arithmetic-functions. (line 69) * -? option (MySQL Cluster programs): mysql-cluster-program-options-common. (line 51) * -append option (ndb_restore): mysql-cluster-programs-ndb-restore. (line 476) * -backup_path option (ndb_restore): mysql-cluster-programs-ndb-restore. (line 307) * -backupid option (ndb_restore): mysql-cluster-programs-ndb-restore. (line 288) * -bind-address option (ndb_mgmd): mysql-cluster-programs-ndb-mgmd. (line 69) * -c option (MySQL Cluster programs): mysql-cluster-program-options-common. (line 76) * -c option (ndb_mgmd) (OBSOLETE): mysql-cluster-programs-ndb-mgmd. (line 188) * -character-sets-dir option (MySQL Cluster programs): mysql-cluster-program-options-common. (line 62) * -config-cache option (ndb_mgmd): mysql-cluster-programs-ndb-mgmd. (line 131) * -config-file option (ndb_mgmd): mysql-cluster-programs-ndb-mgmd. (line 188) * -configdir option (ndb_mgmd): mysql-cluster-programs-ndb-mgmd. (line 95) * -connect-string option (MySQL Cluster programs): mysql-cluster-program-options-common. (line 76) * -core-file option (MySQL Cluster programs): mysql-cluster-program-options-common. (line 96) * -d option (ndb_mgmd): mysql-cluster-programs-ndb-mgmd. (line 219) * -daemon option (ndb_mgmd): mysql-cluster-programs-ndb-mgmd. (line 219) * -debug option (MySQL Cluster programs): mysql-cluster-program-options-common. (line 120) * -disable option prefix: option-modifiers. (line 6) * -disable-indexes option (ndb_restore): mysql-cluster-programs-ndb-restore. (line 720) * -e option (ndb_mgm): mysql-cluster-programs-ndb-mgm. (line 41) * -enable option prefix: option-modifiers. (line 6) * -epoch option (ndb_restore): mysql-cluster-programs-ndb-restore. (line 300) * -exclude-databases option (ndb_restore): mysql-cluster-programs-ndb-restore. (line 581) * -exclude-missing-columns option (ndb_restore): mysql-cluster-programs-ndb-restore. (line 702) * -exclude-tables option (ndb_restore): mysql-cluster-programs-ndb-restore. (line 593) * -execute option (ndb_mgm): mysql-cluster-programs-ndb-mgm. (line 41) * -f option (ndb_mgmd): mysql-cluster-programs-ndb-mgmd. (line 188) * -fields-enclosed-by option (ndb_restore): mysql-cluster-programs-ndb-restore. (line 402) * -fields-optionally-enclosed-by option (ndb_restore): mysql-cluster-programs-ndb-restore. (line 417) * -fields-terminated-by option (ndb_restore): mysql-cluster-programs-ndb-restore. (line 434) * -help option (MySQL Cluster programs): mysql-cluster-program-options-common. (line 51) * -hex option (ndb_restore): mysql-cluster-programs-ndb-restore. (line 450) * -include-databases option (ndb_restore): mysql-cluster-programs-ndb-restore. (line 504) * -include-tables option (ndb_restore): mysql-cluster-programs-ndb-restore. (line 516) * -initial option (ndb_mgmd): mysql-cluster-programs-ndb-mgmd. (line 237) * -initial option (ndbd): mysql-cluster-programs-ndbd. (line 105) * -initial option (ndbmtd): mysql-cluster-programs-ndbd. (line 105) * -initial-start option (ndbd): mysql-cluster-programs-ndbd. (line 165) * -initial-start option (ndbmtd): mysql-cluster-programs-ndbd. (line 165) * -install option (ndb_mgmd): mysql-cluster-programs-ndb-mgmd. (line 518) * -install option (ndbd): mysql-cluster-programs-ndbd. (line 288) * -install option (ndbmtd): mysql-cluster-programs-ndbd. (line 288) * -log-name option (ndb_mgmd): mysql-cluster-programs-ndb-mgmd. (line 269) * -loose option prefix: option-modifiers. (line 6) * -lossy-conversions option (ndb_restore): mysql-cluster-programs-ndb-restore. (line 247) * -maximum option prefix: option-modifiers. (line 6) * -n option (ndbd): mysql-cluster-programs-ndbd. (line 266) * -n option (ndbmtd): mysql-cluster-programs-ndbd. (line 266) * -ndb-log-update-as-write (mysqld option): mysql-cluster-replication-conflict-resolution. (line 64) * -ndb-mgmd-host option (MySQL Cluster programs): mysql-cluster-program-options-common. (line 135) * -ndb-nodeid option (MySQL Cluster programs): mysql-cluster-program-options-common. (line 140) * -ndb-optimized-node-selection option (MySQL Cluster): mysql-cluster-program-options-common. (line 156) * -nodaemon option (ndb_mgmd): mysql-cluster-programs-ndb-mgmd. (line 285) * -nodaemon option (ndbd): mysql-cluster-programs-ndbd. (line 239) * -nodaemon option (ndbmtd): mysql-cluster-programs-ndbd. (line 239) * -nostart option (ndbd): mysql-cluster-programs-ndbd. (line 266) * -nostart option (ndbmtd): mysql-cluster-programs-ndbd. (line 266) * -nowait-nodes option (ndb_mgmd): mysql-cluster-programs-ndb-mgmd. (line 360) * -nowait-nodes option (ndbd): mysql-cluster-programs-ndbd. (line 206) * -nowait-nodes option (ndbmtd): mysql-cluster-programs-ndbd. (line 206) * -p option: password-security-user. (line 17) * -P option (ndb_mgmd): mysql-cluster-programs-ndb-mgmd. (line 309) * -password option: password-security-user. (line 17) * -preserve-trailing-spaces option (ndb_restore): mysql-cluster-programs-ndb-restore. (line 273) * -print-full-config option (ndb_mgmd): mysql-cluster-programs-ndb-mgmd. (line 309) * -print_data option (ndb_restore): mysql-cluster-programs-ndb-restore. (line 376) * -promote-attributes option (ndb_restore): mysql-cluster-programs-ndb-restore. (line 217) * -rebuild-indexes option (ndb_restore): mysql-cluster-programs-ndb-restore. (line 737) * -reload option (ndb_mgmd): mysql-cluster-programs-ndb-mgmd. (line 329) * -remove option (ndb_mgmd): mysql-cluster-programs-ndb-mgmd. (line 555) * -remove option (ndbd): mysql-cluster-programs-ndbd. (line 326) * -remove option (ndbmtd): mysql-cluster-programs-ndbd. (line 326) * -restore_connect option (ndb_restore): mysql-cluster-programs-ndb-restore. (line 145) * -restore_nodeid option (ndb_restore): mysql-cluster-programs-ndb-restore. (line 167) * -restore_skip-table-check option (ndb_restore): mysql-cluster-programs-ndb-restore. (line 180) * -rewrite-database option (ndb_restore): mysql-cluster-programs-ndb-restore. (line 787) * -skip option prefix: option-modifiers. (line 6) * -skip-broken-objects option (ndb_restore): mysql-cluster-programs-ndb-restore. (line 751) * -skip-unknown-objects option (ndb_restore): mysql-cluster-programs-ndb-restore. (line 769) * -tab option (ndb_restore): mysql-cluster-programs-ndb-restore. (line 389) * -usage option (MySQL Cluster programs): mysql-cluster-program-options-common. (line 51) * -V option (MySQL Cluster programs): mysql-cluster-program-options-common. (line 169) * -version option (MySQL Cluster programs): mysql-cluster-program-options-common. (line 169) * .my.cnf file <1>: multiple-server-clients. (line 34) * .my.cnf file <2>: access-denied. (line 101) * .my.cnf file <3>: password-security-user. (line 56) * .my.cnf file <4>: option-files. (line 11) * .my.cnf file: connecting. (line 220) * .mysql_history file <1>: password-security-user. (line 88) * .mysql_history file: mysql-history-file. (line 6) * .pid (process ID) file: myisam-maintenance-schedule. (line 17) * / (division): arithmetic-functions. (line 92) * /etc/passwd <1>: select. (line 330) * /etc/passwd: security-against-attack. (line 106) * := (assignment operator): assignment-operators. (line 15) * := (assignment): user-variables. (line 6) * < (less than): comparison-operators. (line 109) * <<: calculating-days. (line 6) * << (left shift): bit-functions. (line 51) * <= (less than or equal): comparison-operators. (line 102) * <=> (equal to): comparison-operators. (line 79) * <> (not equal): comparison-operators. (line 91) * = (assignment operator): assignment-operators. (line 70) * = (assignment): user-variables. (line 6) * = (equal): comparison-operators. (line 64) * > (greater than): comparison-operators. (line 123) * >= (greater than or equal): comparison-operators. (line 116) * >> (right shift): bit-functions. (line 63) * [api] (MySQL Cluster): mysql-cluster-params-api. (line 6) * [computer] (MySQL Cluster): mysql-cluster-params-other. (line 6) * [mgm] (MySQL Cluster): mysql-cluster-params-mgmd. (line 6) * [mysqld] (MySQL Cluster): mysql-cluster-params-api. (line 6) * [ndb_mgmd] (MySQL Cluster): mysql-cluster-params-mgmd. (line 6) * [ndbd default] (MySQL Cluster): mysql-cluster-params-ndbd. (line 6) * [ndbd] (MySQL Cluster): mysql-cluster-params-ndbd. (line 6) * [sci] (MySQL Cluster): mysql-cluster-params-other. (line 6) * [shm] (MySQL Cluster): mysql-cluster-params-other. (line 6) * [tcp] (MySQL Cluster): mysql-cluster-params-other. (line 6) * \" (double quote): string-syntax. (line 58) * \' (single quote): string-syntax. (line 57) * \. (mysql client command) <1>: batch-commands. (line 6) * \. (mysql client command): batch-mode. (line 90) * \0 (ASCII NUL) <1>: load-data. (line 427) * \0 (ASCII NUL): string-syntax. (line 56) * \\ (escape): string-syntax. (line 64) * \b (backspace) <1>: load-data. (line 428) * \b (backspace): string-syntax. (line 59) * \n (linefeed) <1>: load-data. (line 429) * \n (linefeed): string-syntax. (line 60) * \n (newline) <1>: load-data. (line 429) * \n (newline): string-syntax. (line 60) * \N (NULL): load-data. (line 433) * \r (carriage return) <1>: load-data. (line 430) * \r (carriage return): string-syntax. (line 61) * \t (tab) <1>: load-data. (line 431) * \t (tab): string-syntax. (line 62) * \Z (Control+Z) ASCII 26 <1>: load-data. (line 432) * \Z (Control+Z) ASCII 26: string-syntax. (line 63) * ^ (bitwise XOR): bit-functions. (line 38) * _ (wildcard character): string-syntax. (line 66) * _rowid: create-table. (line 442) * `: identifiers. (line 20) * abort-slave-event-count option, mysqld: replication-options-slave. (line 134) * aborted clients: communication-errors. (line 6) * aborted connection: communication-errors. (line 6) * ABS(): mathematical-functions. (line 54) * access control: connection-access. (line 6) * access denied errors: error-access-denied. (line 6) * access privileges: privilege-system. (line 16) * account names: account-names. (line 6) * account privileges, adding: adding-users. (line 6) * accounts, anonymous user: default-privileges. (line 6) * accounts, root: default-privileges. (line 6) * ACID <1>: innodb-storage-engine. (line 23) * ACID: ansi-diff-transactions. (line 6) * ACLs: privilege-system. (line 16) * ACOS(): mathematical-functions. (line 66) * activating plugins: server-plugin-loading. (line 6) * Active Server Pages (ASP): connector-odbc-usagenotes-apptips-microsoft-asp. (line 6) * ActiveState Perl: activestate-perl. (line 6) * add-drop-database option, mysqldump: mysqldump. (line 331) * add-drop-table option, mysqldump: mysqldump. (line 340) * add-drop-trigger option, mysqldump: mysqldump. (line 345) * add-locks option, mysqldump: mysqldump. (line 357) * add-user option, mysqlmanager: instance-manager-command-options. (line 27) * ADDDATE(): date-and-time-functions. (line 133) * adding, character sets: adding-character-set. (line 12) * adding, native functions: adding-native-function. (line 6) * adding, new account privileges: adding-users. (line 6) * adding, new functions: adding-functions. (line 12) * adding, new user privileges: adding-users. (line 6) * adding, new users: unix-postinstallation. (line 371) * adding, procedures: adding-procedures. (line 11) * adding, user-defined functions: adding-udf. (line 15) * addition (+): arithmetic-functions. (line 55) * ADDTIME(): date-and-time-functions. (line 151) * addtodest option, mysqlhotcopy: mysqlhotcopy. (line 83) * administration of MySQL Cluster: mysql-cluster-programs-ndb-mgm. (line 6) * administration, server: mysqladmin. (line 6) * administrative programs: programs-overview. (line 165) * AES_DECRYPT(): encryption-functions. (line 91) * AES_ENCRYPT(): encryption-functions. (line 97) * After create, thread state: general-thread-states. (line 11) * age, calculating: date-calculations. (line 6) * alias names, case sensitivity: identifier-case-sensitivity. (line 6) * aliases, for expressions: group-by-hidden-columns. (line 80) * aliases, for tables: select. (line 160) * aliases, in GROUP BY clauses: group-by-hidden-columns. (line 80) * aliases, names: identifiers. (line 13) * aliases, on expressions: select. (line 106) * ALL <1>: all-subqueries. (line 6) * ALL: select. (line 469) * ALL join type, optimizer: explain-output. (line 231) * all-databases option, mysqlcheck: mysqlcheck. (line 201) * all-databases option, mysqldump: mysqldump. (line 364) * all-in-1 option, mysqlcheck: mysqlcheck. (line 207) * all-tablespaces option, mysqldump: mysqldump. (line 370) * allocating local table, thread state: delayed-insert-thread-states. (line 17) * allow-keywords option, mysqldump: mysqldump. (line 380) * allow-suspicious-udfs option, mysqld <1>: privileges-options. (line 41) * allow-suspicious-udfs option, mysqld: server-options. (line 83) * ALLOW_INVALID_DATES SQL mode: server-sql-mode. (line 91) * allowold option, mysqlhotcopy: mysqlhotcopy. (line 88) * ALTER COLUMN: alter-table. (line 307) * ALTER DATABASE: alter-database. (line 6) * ALTER EVENT: alter-event. (line 6) * ALTER EVENT, and replication: replication-features-invoked. (line 49) * ALTER FUNCTION: alter-function. (line 6) * ALTER LOGFILE GROUP: alter-logfile-group. (line 6) * ALTER PROCEDURE: alter-procedure. (line 6) * ALTER SCHEMA: alter-database. (line 6) * ALTER SERVER: alter-server. (line 6) * ALTER TABLE <1>: alter-table-problems. (line 6) * ALTER TABLE: alter-table. (line 12) * ALTER TABLESPACE: alter-tablespace. (line 6) * ALTER VIEW: alter-view. (line 6) * altering, database: alter-database. (line 6) * altering, schema: alter-database. (line 6) * analyze option, myisamchk: myisamchk-other-options. (line 9) * analyze option, mysqlcheck: mysqlcheck. (line 213) * ANALYZE TABLE: analyze-table. (line 6) * ANALYZE TABLE, and partitioning: partitioning-maintenance. (line 6) * Analyzing, thread state: general-thread-states. (line 18) * AND, bitwise: bit-functions. (line 29) * AND, logical: logical-operators. (line 48) * angel-pid-file option, mysqlmanager: instance-manager-command-options. (line 32) * anonymous user <1>: request-access. (line 26) * anonymous user <2>: connection-access. (line 25) * anonymous user: default-privileges. (line 6) * ANSI mode, running: ansi-mode. (line 6) * ansi option, mysqld: server-options. (line 102) * ANSI SQL mode: server-sql-mode. (line 59) * ANSI_QUOTES SQL mode: server-sql-mode. (line 109) * answering questions, etiquette: mailing-list-use. (line 6) * ANY: any-in-some-subqueries. (line 6) * Apache: apache. (line 6) * API node (MySQL Cluster), defined: mysql-cluster-basics. (line 6) * API nodes: mysql-cluster-programs-mysqld. (line 6) * API's, list of: packages. (line 6) * APIs: connectors-apis. (line 24) * APIs, Perl: apis-perl. (line 6) * apply_status table (OBSOLETE): mysql-cluster-replication-schema. (line 79) * approximate-value literals: precision-math. (line 14) * Arbitration: mysql-cluster-ndbd-definition. (line 2557) * ArbitrationDelay <1>: mysql-cluster-api-definition. (line 157) * ArbitrationDelay: mysql-cluster-mgm-definition. (line 221) * ArbitrationRank <1>: mysql-cluster-api-definition. (line 129) * ArbitrationRank: mysql-cluster-mgm-definition. (line 183) * ArbitrationTimeout: mysql-cluster-ndbd-definition. (line 2538) * arbitrator: faqs-mysql-cluster. (line 6) * ARCHIVE storage engine <1>: archive-storage-engine. (line 6) * ARCHIVE storage engine: storage-engines. (line 23) * Area() <1>: multipolygon-property-functions. (line 8) * Area(): polygon-property-functions. (line 8) * argument processing: udf-arguments. (line 6) * arithmetic expressions: arithmetic-functions. (line 55) * arithmetic functions: bit-functions. (line 6) * AS <1>: join. (line 6) * AS: select. (line 134) * AS/400: i5os-installation. (line 6) * AsBinary(): functions-to-convert-geometries-between-formats. (line 9) * ASCII(): string-functions. (line 103) * ASIN(): mathematical-functions. (line 78) * assignment operator, :=: assignment-operators. (line 15) * assignment operator, =: assignment-operators. (line 70) * assignment operators: assignment-operators. (line 6) * AsText(): functions-to-convert-geometries-between-formats. (line 16) * asynchronous replication: mysql-cluster-replication. (line 20) * ATAN(): mathematical-functions. (line 101) * ATAN2(): mathematical-functions. (line 111) * attackers, security against: security-against-attack. (line 6) * attribute demotion, replication: replication-features-different-data-types. (line 6) * attribute promotion, ndb_restore: mysql-cluster-programs-ndb-restore. (line 217) * attribute promotion, replication: replication-features-different-data-types. (line 6) * auto-generate-sql option, mysqlslap: mysqlslap. (line 215) * auto-generate-sql-add-autoincrement option, mysqlslap: mysqlslap. (line 220) * auto-generate-sql-execute-number option, mysqlslap: mysqlslap. (line 225) * auto-generate-sql-guid-primary option, mysqlslap: mysqlslap. (line 230) * auto-generate-sql-load-type option, mysqlslap: mysqlslap. (line 235) * auto-generate-sql-secondary-indexes option, mysqlslap: mysqlslap. (line 243) * auto-generate-sql-unique-query-number option, mysqlslap: mysqlslap. (line 249) * auto-generate-sql-unique-write-number option, mysqlslap: mysqlslap. (line 257) * auto-generate-sql-write-number option, mysqlslap: mysqlslap. (line 263) * AUTO-INCREMENT, ODBC: connector-odbc-usagenotes-functionality-last-insert-id. (line 6) * auto-rehash option, mysql: mysql-command-options. (line 157) * auto-repair option, mysqlcheck: mysqlcheck. (line 217) * AUTO_INCREMENT <1>: numeric-types. (line 6) * AUTO_INCREMENT: example-auto-increment. (line 6) * AUTO_INCREMENT, and NULL values: problems-with-null. (line 71) * AUTO_INCREMENT, and replication: replication-features-auto-increment. (line 6) * auto_increment_increment system variable: replication-options-master. (line 21) * auto_increment_offset system variable: replication-options-master. (line 224) * autoclose option, mysqld_safe: mysqld-safe. (line 123) * autocommit session variable: server-system-variables. (line 573) * automatic_sp_privileges system variable: server-system-variables. (line 614) * AutoReconnect, API and SQL nodes: mysql-cluster-api-definition. (line 273) * AVG(): group-by-functions. (line 58) * AVG(DISTINCT): group-by-functions. (line 58) * back_log system variable: server-system-variables. (line 641) * backslash, escape character: string-syntax. (line 6) * backspace (\b) <1>: load-data. (line 428) * backspace (\b): string-syntax. (line 59) * backup identifiers, native backup and restore: mysql-cluster-backup-using-management-client. (line 105) * backup option, myisamchk: myisamchk-repair-options. (line 10) * backup option, myisampack: myisampack. (line 51) * BACKUP TABLE: backup-table. (line 6) * BackupDataBufferSize <1>: mysql-cluster-backup-configuration. (line 8) * BackupDataBufferSize: mysql-cluster-ndbd-definition. (line 2992) * BackupDataDir: mysql-cluster-ndbd-definition. (line 332) * BackupLogBufferSize <1>: mysql-cluster-backup-configuration. (line 13) * BackupLogBufferSize: mysql-cluster-ndbd-definition. (line 3016) * BackupMaxWriteSize <1>: mysql-cluster-backup-configuration. (line 29) * BackupMaxWriteSize: mysql-cluster-ndbd-definition. (line 3117) * BackupMemory <1>: mysql-cluster-backup-configuration. (line 18) * BackupMemory: mysql-cluster-ndbd-definition. (line 3051) * BackupReportFrequency: mysql-cluster-ndbd-definition. (line 3075) * backups: backup-and-recovery. (line 15) * backups, database: backup-table. (line 6) * backups, databases and tables <1>: mysqlhotcopy. (line 6) * backups, databases and tables: mysqldump. (line 6) * backups, in MySQL Cluster <1>: mysql-cluster-backup-configuration. (line 6) * backups, in MySQL Cluster <2>: mysql-cluster-backup-using-management-client. (line 6) * backups, in MySQL Cluster <3>: mysql-cluster-backup-concepts. (line 6) * backups, in MySQL Cluster <4>: mysql-cluster-backup. (line 13) * backups, in MySQL Cluster: mysql-cluster-programs-ndb-restore. (line 6) * backups, in MySQL Cluster replication: mysql-cluster-replication-backups. (line 11) * backups, InnoDB: innodb-backup. (line 12) * backups, troubleshooting, in MySQL Cluster: mysql-cluster-backup-troubleshooting. (line 6) * backups, with mysqldump: using-mysqldump. (line 14) * BackupWriteSize <1>: mysql-cluster-backup-configuration. (line 24) * BackupWriteSize: mysql-cluster-ndbd-definition. (line 3099) * base64-output option, mysqlbinlog: mysqlbinlog. (line 178) * basedir option, mysql.server: mysql-server. (line 36) * basedir option, mysql_install_db: mysql-install-db. (line 51) * basedir option, mysql_upgrade: mysql-upgrade. (line 120) * basedir option, mysqld: server-options. (line 114) * basedir option, mysqld_safe: mysqld-safe. (line 135) * basedir system variable: server-system-variables. (line 676) * batch mode: batch-mode. (line 6) * batch option, mysql: mysql-command-options. (line 171) * batch SQL files: mysql. (line 15) * BatchByteSize: mysql-cluster-api-definition. (line 173) * batched updates (MySQL Cluster Replication): mysql-cluster-replication-starting. (line 71) * BatchSize: mysql-cluster-api-definition. (line 199) * BatchSizePerLocalScan: mysql-cluster-ndbd-definition. (line 921) * Bazaar tree: installing-development-tree. (line 6) * BdMPolyFromText(): gis-wkt-functions. (line 59) * BdMPolyFromWKB(): gis-wkb-functions. (line 61) * BdPolyFromText(): gis-wkt-functions. (line 65) * BdPolyFromWKB(): gis-wkb-functions. (line 67) * BEGIN <1>: begin-end. (line 6) * BEGIN: commit. (line 6) * BEGIN, XA transactions: xa-statements. (line 6) * benchmark suite: mysql-benchmarks. (line 6) * BENCHMARK(): information-functions. (line 33) * benchmarks: custom-benchmarks. (line 6) * BETWEEN ... AND: comparison-operators. (line 195) * big-tables option, mysqld: server-options. (line 135) * big5: faqs-cjk. (line 6) * big_tables session variable: server-system-variables. (line 698) * BIGINT data type: numeric-type-overview. (line 125) * BIN(): string-functions. (line 118) * BINARY: cast-functions. (line 13) * BINARY data type <1>: binary-varbinary. (line 6) * BINARY data type: string-type-overview. (line 151) * binary distributions, installing: binary-installation. (line 6) * binary log: binary-log. (line 13) * binary log, event groups: set-global-sql-slave-skip-counter. (line 6) * binary logging, and MySQL Cluster: mysql-cluster-limitations-exclusive-to-cluster. (line 22) * bind-address option, mysql: mysql-command-options. (line 181) * bind-address option, mysqladmin: mysqladmin. (line 302) * bind-address option, mysqlbinlog: mysqlbinlog. (line 226) * bind-address option, mysqlcheck: mysqlcheck. (line 222) * bind-address option, mysqld: server-options. (line 158) * bind-address option, mysqldump: mysqldump. (line 385) * bind-address option, mysqlimport: mysqlimport. (line 133) * bind-address option, mysqlmanager: instance-manager-command-options. (line 46) * bind-address option, mysqlshow: mysqlshow. (line 114) * BINLOG: binlog. (line 6) * Binlog Dump, thread command: thread-commands. (line 8) * BINLOG statement, mysqlbinlog output: mysqlbinlog-row-events. (line 6) * binlog-do-db option, mysqld: replication-options-binary-log. (line 132) * binlog-format option, mysqld: server-options. (line 181) * binlog-ignore-db option, mysqld: replication-options-binary-log. (line 257) * binlog-row-event-max-size option, mysqld: replication-options-binary-log. (line 20) * binlog_cache_size system variable: replication-options-binary-log. (line 364) * binlog_direct_non_transactional_updates system variable: replication-options-binary-log. (line 400) * binlog_format system variable: replication-options-binary-log. (line 455) * binlog_index table (OBSOLETE): mysql-cluster-replication-schema. (line 6) * BIT data type: numeric-type-overview. (line 35) * BIT_AND(): group-by-functions. (line 69) * BIT_COUNT: calculating-days. (line 6) * BIT_COUNT(): bit-functions. (line 84) * bit_functions, example: calculating-days. (line 6) * BIT_LENGTH(): string-functions. (line 127) * BIT_OR: calculating-days. (line 6) * BIT_OR(): group-by-functions. (line 78) * BIT_XOR(): group-by-functions. (line 85) * BLACKHOLE storage engine <1>: blackhole-storage-engine. (line 6) * BLACKHOLE storage engine: storage-engines. (line 23) * BLOB columns, default values: blob. (line 53) * BLOB columns, indexing <1>: create-table. (line 494) * BLOB columns, indexing: column-indexes. (line 15) * BLOB data type <1>: blob. (line 6) * BLOB data type: string-type-overview. (line 180) * BLOB, inserting binary data: string-syntax. (line 142) * BLOB, size: storage-requirements. (line 197) * blob-info option, ndb_desc: mysql-cluster-programs-ndb-desc. (line 185) * Block Nested-Loop join algorithm: nested-loop-joins. (line 6) * block-search option, myisamchk: myisamchk-other-options. (line 18) * blocks, ndbinfo table: mysql-cluster-ndbinfo-blocks. (line 6) * BOOL data type: numeric-type-overview. (line 45) * BOOLEAN data type: numeric-type-overview. (line 45) * boolean options: option-modifiers. (line 6) * bootstrap option, mysqld: server-options. (line 254) * Borland Builder 4: connector-odbc-usagenotes-apptips-borland-builder. (line 6) * Boundary(): general-geometry-property-functions. (line 70) * brackets, square: data-types. (line 42) * brief option, mysqlaccess: mysqlaccess. (line 71) * Buffer pool, InnoDB: innodb-buffer-pool. (line 6) * buffer sizes, client: connectors-apis. (line 24) * buffer sizes, mysqld server: server-parameters. (line 6) * Buffer(): spatial-operators. (line 11) * bug reports, criteria for: bug-reports. (line 6) * bugs database: bug-reports. (line 6) * bugs, known: bugs. (line 6) * bugs, MySQL Cluster, reporting: mysql-cluster-programs-ndb-error-reporter. (line 6) * bugs, reporting: bug-reports. (line 6) * bugs.mysql.com: bug-reports. (line 6) * BuildIndexThreads: mysql-cluster-ndbd-definition. (line 3273) * building, client programs: building-clients. (line 11) * bulk_insert_buffer_size system variable: server-system-variables. (line 713) * C API, data types: c. (line 25) * C API, functions: c-api-function-overview. (line 6) * C API, linking problems: c-api-linking-problems. (line 6) * C prepared statement API, functions <1>: c-api-prepared-statement-function-overview. (line 6) * C prepared statement API, functions: c-api-prepared-statement-type-conversions. (line 6) * C prepared statement API, type codes: c-api-prepared-statement-type-codes. (line 6) * C++ Builder: connector-odbc-usagenotes-apptips-borland-cppbuilder. (line 6) * C++ compiler cannot create executables: compilation-problems. (line 62) * C++ compiler, gcc: source-configuration-options. (line 397) * C:\my.cnf file: multiple-server-clients. (line 34) * CACHE INDEX: cache-index. (line 6) * CACHE INDEX, and partitioning: partitioning-limitations. (line 379) * caches, clearing: flush. (line 6) * calculating, dates: date-calculations. (line 6) * calendar: mysql-calendar. (line 6) * CALL: call. (line 6) * calling sequences for aggregate functions, UDF: udf-aggr-calling. (line 6) * calling sequences for simple functions, UDF: udf-calling. (line 6) * can't create/write to file: cannot-create. (line 6) * carriage return (\r) <1>: load-data. (line 430) * carriage return (\r): string-syntax. (line 61) * CASE <1>: case-statement. (line 6) * CASE: control-flow-functions. (line 14) * case sensitivity, in access checking: grant-table-structure. (line 246) * case sensitivity, in identifiers: identifier-case-sensitivity. (line 6) * case sensitivity, in names: identifier-case-sensitivity. (line 6) * case sensitivity, in searches: case-sensitivity. (line 6) * case sensitivity, in string comparisons: string-comparison-functions. (line 17) * case sensitivity, of replication filtering options: replication-rules. (line 56) * case-sensitivity, of database names: extensions-to-ansi. (line 38) * case-sensitivity, of table names: extensions-to-ansi. (line 38) * CAST: cast-functions. (line 39) * cast functions: cast-functions. (line 6) * cast operators: cast-functions. (line 6) * casts <1>: cast-functions. (line 6) * casts <2>: comparison-operators. (line 38) * casts: type-conversion. (line 6) * CC environment variable <1>: environment-variables. (line 18) * CC environment variable <2>: compilation-problems. (line 88) * CC environment variable: source-configuration-options. (line 397) * cc1plus problems: compilation-problems. (line 37) * CEIL(): mathematical-functions. (line 123) * CEILING(): mathematical-functions. (line 127) * Centroid(): multipolygon-property-functions. (line 26) * CFLAGS environment variable <1>: environment-variables. (line 18) * CFLAGS environment variable: compilation-problems. (line 88) * cflags option, mysql_config: mysql-config. (line 11) * CHANGE MASTER TO: change-master-to. (line 6) * CHANGE MASTER TO, in MySQL Cluster: mysql-cluster-replication-preparation. (line 37) * Change user, thread command: thread-commands. (line 13) * ChangeLog: news. (line 18) * changes to privileges: privilege-changes. (line 6) * changes, log: news. (line 18) * changes, MySQL 5.1: news-5-1-x. (line 76) * changes, MySQL Cluster <1>: mysql-cluster-news-series. (line 14) * changes, MySQL Cluster: mysql-cluster-news. (line 16) * Changing master, thread state: slave-connection-thread-states. (line 9) * changing socket location <1>: problems-with-mysql-sock. (line 26) * changing socket location <2>: automatic-start. (line 139) * changing socket location: source-configuration-options. (line 377) * changing, column: alter-table. (line 307) * changing, field: alter-table. (line 307) * changing, table <1>: alter-table-problems. (line 6) * changing, table: alter-table. (line 12) * CHAR data type <1>: string-types. (line 14) * CHAR data type: string-type-overview. (line 89) * CHAR VARYING data type: string-type-overview. (line 121) * CHAR(): string-functions. (line 134) * CHAR_LENGTH(): string-functions. (line 176) * CHARACTER data type: string-type-overview. (line 89) * character set repertoire: charset-repertoire. (line 6) * Character sets: charset. (line 22) * character sets: source-configuration-options. (line 434) * character sets, adding: adding-character-set. (line 12) * character sets, and MySQL Cluster (replication): mysql-cluster-replication-issues. (line 69) * character sets, and replication: replication-features-charset. (line 6) * CHARACTER VARYING data type: string-type-overview. (line 121) * character-set-client-handshake option, mysqld: server-options. (line 289) * character-set-filesystem option, mysqld: server-options. (line 306) * character-set-server option, mysqld: server-options. (line 328) * character-sets-dir option, myisamchk: myisamchk-repair-options. (line 14) * character-sets-dir option, myisampack: myisampack. (line 56) * character-sets-dir option, mysql: mysql-command-options. (line 192) * character-sets-dir option, mysqladmin: mysqladmin. (line 313) * character-sets-dir option, mysqlbinlog: mysqlbinlog. (line 237) * character-sets-dir option, mysqlcheck: mysqlcheck. (line 233) * character-sets-dir option, mysqld: server-options. (line 269) * character-sets-dir option, mysqldump: mysqldump. (line 396) * character-sets-dir option, mysqlimport: mysqlimport. (line 144) * character-sets-dir option, mysqlshow: mysqlshow. (line 125) * CHARACTER_LENGTH(): string-functions. (line 183) * character_set_client system variable: server-system-variables. (line 747) * character_set_connection system variable: server-system-variables. (line 785) * character_set_database system variable: server-system-variables. (line 801) * character_set_filesystem system variable: server-system-variables. (line 840) * character_set_results system variable: server-system-variables. (line 871) * character_set_server system variable: server-system-variables. (line 886) * character_set_system system variable: server-system-variables. (line 905) * CHARACTER_SETS, INFORMATION_SCHEMA table: character-sets-table. (line 6) * character_sets_dir system variable: server-system-variables. (line 919) * characters, multi-byte: multi-byte-characters. (line 6) * charset command, mysql: mysql-commands. (line 61) * charset option, comp_err: comp-err. (line 30) * CHARSET(): information-functions. (line 79) * check option, myisamchk: myisamchk-check-options. (line 9) * check option, mysqlcheck: mysqlcheck. (line 238) * check options, myisamchk: myisamchk-check-options. (line 6) * CHECK TABLE: check-table. (line 6) * CHECK TABLE, and partitioning: partitioning-maintenance. (line 6) * check-only-changed option, myisamchk: myisamchk-check-options. (line 14) * check-only-changed option, mysqlcheck: mysqlcheck. (line 242) * check-password-file option, mysqlmanager: instance-manager-command-options. (line 50) * check-upgrade option, mysqlcheck: mysqlcheck. (line 247) * Checking master version, thread state: slave-io-thread-states. (line 20) * checking permissions, thread state: general-thread-states. (line 23) * checking privileges on cached query, thread state: query-cache-thread-states. (line 9) * checking query cache for query, thread state: query-cache-thread-states. (line 14) * Checking table, thread state: general-thread-states. (line 28) * checking, tables for errors: myisam-check. (line 6) * CHECKPOINT Events (MySQL Cluster): mysql-cluster-log-events. (line 35) * checkpoint option, mysqlhotcopy: mysqlhotcopy. (line 93) * Checksum: mysql-cluster-tcp-definition. (line 158) * Checksum (MySQL Cluster) <1>: mysql-cluster-sci-definition. (line 189) * Checksum (MySQL Cluster): mysql-cluster-shm-definition. (line 126) * checksum errors: solaris-installation. (line 11) * CHECKSUM TABLE: checksum-table. (line 6) * Chinese, Japanese, Korean character sets, frequently asked questions: faqs-cjk. (line 6) * choosing types: choosing-types. (line 6) * choosing, a MySQL version: which-version. (line 18) * chroot option, mysqld: server-options. (line 350) * chroot option, mysqlhotcopy: mysqlhotcopy. (line 98) * circular replication, in MySQL Cluster <1>: mysql-cluster-replication-conflict-resolution. (line 6) * circular replication, in MySQL Cluster <2>: mysql-cluster-replication-multi-master. (line 6) * circular replication, in MySQL Cluster: mysql-cluster-replication-issues. (line 76) * CJK (Chinese, Japanese, Korean), Access, PHP, etc.: faqs-cjk. (line 6) * CJK (Chinese, Japanese, Korean), availability of specific characters: faqs-cjk. (line 6) * CJK (Chinese, Japanese, Korean), available character sets: faqs-cjk. (line 6) * CJK (Chinese, Japanese, Korean), big5: faqs-cjk. (line 6) * CJK (Chinese, Japanese, Korean), character sets available: faqs-cjk. (line 6) * CJK (Chinese, Japanese, Korean), characters displayed as question marks: faqs-cjk. (line 6) * CJK (Chinese, Japanese, Korean), CJKV: faqs-cjk. (line 6) * CJK (Chinese, Japanese, Korean), collations: faqs-cjk. (line 6) * CJK (Chinese, Japanese, Korean), conversion problems with Japanese character sets: faqs-cjk. (line 6) * CJK (Chinese, Japanese, Korean), data truncation: faqs-cjk. (line 6) * CJK (Chinese, Japanese, Korean), Database and table names: faqs-cjk. (line 6) * CJK (Chinese, Japanese, Korean), documentation in Chinese: faqs-cjk. (line 6) * CJK (Chinese, Japanese, Korean), documentation in Japanese: faqs-cjk. (line 6) * CJK (Chinese, Japanese, Korean), documentation in Korean: faqs-cjk. (line 6) * CJK (Chinese, Japanese, Korean), gb2312, gbk: faqs-cjk. (line 6) * CJK (Chinese, Japanese, Korean), Japanese character sets: faqs-cjk. (line 6) * CJK (Chinese, Japanese, Korean), Korean character set: faqs-cjk. (line 6) * CJK (Chinese, Japanese, Korean), LIKE and FULLTEXT: faqs-cjk. (line 6) * CJK (Chinese, Japanese, Korean), MySQL 4.0 behavior: faqs-cjk. (line 6) * CJK (Chinese, Japanese, Korean), ORDER BY treatment: faqs-cjk. (line 6) * CJK (Chinese, Japanese, Korean), problems with Access, PHP, etc.: faqs-cjk. (line 6) * CJK (Chinese, Japanese, Korean), problems with Big5 character sets (Chinese): faqs-cjk. (line 6) * CJK (Chinese, Japanese, Korean), problems with data truncation: faqs-cjk. (line 6) * CJK (Chinese, Japanese, Korean), problems with euckr character set (Korean): faqs-cjk. (line 6) * CJK (Chinese, Japanese, Korean), problems with GB character sets (Chinese): faqs-cjk. (line 6) * CJK (Chinese, Japanese, Korean), problems with LIKE and FULLTEXT: faqs-cjk. (line 6) * CJK (Chinese, Japanese, Korean), problems with Yen sign (Japanese): faqs-cjk. (line 6) * CJK (Chinese, Japanese, Korean), rejected characters: faqs-cjk. (line 6) * CJK (Chinese, Japanese, Korean), sort order problems: faqs-cjk. (line 6) * CJK (Chinese, Japanese, Korean), sorting problems: faqs-cjk. (line 6) * CJK (Chinese, Japanese, Korean), testing availability of characters: faqs-cjk. (line 6) * CJK (Chinese, Japanese, Korean), Unicode collations: faqs-cjk. (line 6) * CJK (Chinese, Japanese, Korean), Vietnamese: faqs-cjk. (line 6) * CJK (Chinese, Japanese, Korean), Yen sign: faqs-cjk. (line 6) * CJK, FAQ: faqs-cjk. (line 6) * clean-password-file option, mysqlmanager: instance-manager-command-options. (line 55) * cleaning up, thread state: general-thread-states. (line 32) * clear command, mysql: mysql-commands. (line 70) * clearing, caches: flush. (line 6) * Clearing, thread state: event-scheduler-thread-states. (line 10) * client connection threads: connection-threads. (line 6) * client programs: programs-overview. (line 124) * client programs, building: building-clients. (line 11) * client tools: connectors-apis. (line 24) * clients, debugging: debugging-client. (line 6) * clients, threaded: threaded-clients. (line 6) * CLOSE: close. (line 6) * Close stmt, thread command: thread-commands. (line 17) * closing tables, thread state: general-thread-states. (line 37) * closing, tables: table-cache. (line 6) * cluster database (OBSOLETE): mysql-cluster-replication-schema. (line 6) * cluster logs <1>: mysql-cluster-logging-management-commands. (line 6) * cluster logs: mysql-cluster-event-reports. (line 12) * cluster.binlog_index table (OBSOLETE): mysql-cluster-replication-schema. (line 6) * cluster_replication database (OBSOLETE): mysql-cluster-replication-schema. (line 6) * clustered index, InnoDB: innodb-index-types. (line 6) * Clustering: mysql-cluster. (line 16) * CLUSTERLOG commands (MySQL Cluster): mysql-cluster-logging-management-commands. (line 8) * CLUSTERLOG STATISTICS command (MySQL Cluster): mysql-cluster-log-statistics. (line 6) * CMake: windows-source-build. (line 6) * COALESCE(): comparison-operators. (line 227) * COERCIBILITY(): information-functions. (line 90) * ColdFusion: connector-odbc-usagenotes-apptips-coldfusion. (line 6) * collating, strings: string-collating. (line 6) * collation names: charset-collation-names. (line 6) * COLLATION(): information-functions. (line 116) * collation, adding: adding-collation. (line 13) * collation, INFORMATION_SCHEMA: charset-collation-information-schema. (line 6) * collation, modifying: adding-collation. (line 59) * collation-server option, mysqld: server-options. (line 370) * COLLATION_CHARACTER_SET_APPLICABILITY, INFORMATION_SCHEMA table: collation-character-set-applicability-table. (line 6) * collation_connection system variable: server-system-variables. (line 938) * collation_database system variable: server-system-variables. (line 952) * collation_server system variable: server-system-variables. (line 991) * COLLATIONS, INFORMATION_SCHEMA table: collations-table. (line 6) * collations, naming conventions: charset-collation-names. (line 6) * column alias, problems: problems-with-alias. (line 6) * column alias, quoting <1>: problems-with-alias. (line 6) * column alias, quoting: identifiers. (line 81) * column comments: create-table. (line 354) * column format: create-table. (line 359) * column names, case sensitivity: identifier-case-sensitivity. (line 6) * column storage: create-table. (line 379) * column, changing: alter-table. (line 307) * column, types: data-types. (line 30) * column-names option, mysql: mysql-command-options. (line 197) * column-type-info option, mysql: mysql-command-options. (line 201) * COLUMN_PRIVILEGES, INFORMATION_SCHEMA table: column-privileges-table. (line 6) * columns option, mysqlimport: mysqlimport. (line 149) * columns, displaying: mysqlshow. (line 6) * columns, indexes: column-indexes. (line 6) * COLUMNS, INFORMATION_SCHEMA table: columns-table. (line 6) * columns, names: identifiers. (line 13) * columns, other types: other-vendor-data-types. (line 6) * columns, selecting: selecting-columns. (line 6) * columns, storage requirements: storage-requirements. (line 6) * comma-separated values data, reading <1>: select. (line 402) * comma-separated values data, reading: load-data. (line 327) * command options (MySQL Cluster), mysqld: mysql-cluster-program-options-mysqld. (line 6) * command options (MySQL Cluster), ndb_mgm: mysql-cluster-programs-ndb-mgm. (line 27) * command options (MySQL Cluster), ndb_mgmd: mysql-cluster-programs-ndb-mgmd. (line 12) * command options (MySQL Cluster), ndbd: mysql-cluster-programs-ndbd. (line 17) * command options, mysql: mysql-command-options. (line 6) * command options, mysqladmin: mysqladmin. (line 212) * command options, mysqld: server-options. (line 6) * command syntax: manual-conventions. (line 120) * command-line history, mysql: mysql-history-file. (line 6) * command-line options (MySQL Cluster): mysql-cluster-program-options-common. (line 6) * command-line tool: mysql. (line 15) * commands out of sync: commands-out-of-sync. (line 6) * commands, for binary distribution: binary-installation. (line 77) * comment syntax: comments. (line 6) * comments option, mysql: mysql-command-options. (line 207) * comments option, mysqldump: mysqldump. (line 401) * comments, adding: comments. (line 6) * comments, starting: ansi-diff-comments. (line 6) * COMMIT <1>: commit. (line 6) * COMMIT: ansi-diff-transactions. (line 6) * commit option, mysqlaccess: mysqlaccess. (line 75) * commit option, mysqlslap: mysqlslap. (line 268) * COMMIT, XA transactions: xa-statements. (line 6) * Committing events to binlog, thread state: mysql-cluster-thread-states. (line 6) * comp_err <1>: comp-err. (line 6) * comp_err: programs-overview. (line 68) * comp_err, charset option: comp-err. (line 30) * comp_err, debug option: comp-err. (line 35) * comp_err, debug-info option: comp-err. (line 40) * comp_err, header_file option: comp-err. (line 44) * comp_err, help option: comp-err. (line 26) * comp_err, in_file option: comp-err. (line 48) * comp_err, name_file option: comp-err. (line 53) * comp_err, out_dir option: comp-err. (line 57) * comp_err, out_file option: comp-err. (line 62) * comp_err, statefile option: comp-err. (line 66) * comp_err, version option: comp-err. (line 71) * compact option, mysqldump: mysqldump. (line 408) * comparison operators: comparison-operators. (line 6) * compatibility, between MySQL versions: upgrading-from-previous-series. (line 6) * compatibility, with mSQL: regexp. (line 32) * compatibility, with ODBC <1>: join. (line 145) * compatibility, with ODBC <2>: create-table. (line 277) * compatibility, with ODBC <3>: comparison-operators. (line 153) * compatibility, with ODBC <4>: type-conversion. (line 44) * compatibility, with ODBC <5>: numeric-type-overview. (line 228) * compatibility, with ODBC <6>: identifier-qualifiers. (line 41) * compatibility, with ODBC: server-system-variables. (line 4937) * compatibility, with Oracle <1>: describe. (line 39) * compatibility, with Oracle <2>: group-by-functions. (line 239) * compatibility, with Oracle: extensions-to-ansi. (line 99) * compatibility, with PostgreSQL: extensions-to-ansi. (line 193) * compatibility, with standard SQL: compatibility. (line 15) * compatibility, with Sybase: use. (line 27) * compatible option, mysqldump: mysqldump. (line 423) * compiler, C++ gcc: source-configuration-options. (line 397) * compiling clients, on Unix: building-clients. (line 25) * compiling clients, on Windows: building-clients. (line 39) * compiling, optimizing: system-optimization. (line 6) * compiling, problems: compilation-problems. (line 6) * compiling, speed: compile-and-link-options. (line 6) * compiling, statically: source-configuration-options. (line 389) * compiling, user-defined functions: udf-compiling. (line 6) * complete-insert option, mysqldump: mysqldump. (line 443) * completion_type system variable: server-system-variables. (line 1010) * compliance, Y2K: y2k-issues. (line 6) * composite partitioning: partitioning-subpartitions. (line 26) * compound statements: sql-syntax-compound-statements. (line 16) * compress option, mysql: mysql-command-options. (line 214) * compress option, mysqladmin: mysqladmin. (line 318) * compress option, mysqlcheck: mysqlcheck. (line 255) * compress option, mysqldump: mysqldump. (line 448) * compress option, mysqlimport: mysqlimport. (line 155) * compress option, mysqlshow: mysqlshow. (line 130) * compress option, mysqlslap: mysqlslap. (line 273) * COMPRESS(): encryption-functions. (line 131) * compressed tables <1>: compressed-format. (line 6) * compressed tables: myisampack. (line 6) * CompressedBackup: mysql-cluster-ndbd-definition. (line 1704) * CompressedLCP: mysql-cluster-ndbd-definition. (line 1733) * CONCAT(): string-functions. (line 187) * CONCAT_WS(): string-functions. (line 214) * concatenation, string <1>: string-functions. (line 187) * concatenation, string: string-syntax. (line 12) * concurrency option, mysqlslap: mysqlslap. (line 278) * concurrent inserts <1>: concurrent-inserts. (line 6) * concurrent inserts: internal-locking. (line 76) * concurrent_insert system variable: server-system-variables. (line 1049) * Conditions: declare-condition. (line 6) * config-file option, my_print_defaults: my-print-defaults. (line 29) * config-file option, mysqld_multi: mysqld-multi. (line 100) * config-file option, ndb_config: mysql-cluster-programs-ndb-config. (line 91) * config.cache: compilation-problems. (line 14) * config.cache file: compilation-problems. (line 6) * config.ini (MySQL Cluster) <1>: mysql-cluster-programs-ndb-mgmd. (line 495) * config.ini (MySQL Cluster) <2>: mysql-cluster-config-example. (line 6) * config.ini (MySQL Cluster) <3>: mysql-cluster-config-file. (line 22) * config.ini (MySQL Cluster): mysql-cluster-install-configuration. (line 6) * config_params, ndbinfo table: mysql-cluster-ndbinfo-config-params. (line 6) * configinfo option, ndb_config: mysql-cluster-programs-ndb-config. (line 241) * configuration files: access-denied. (line 101) * configuration options: source-configuration-options. (line 6) * configuration, MySQL Cluster: mysql-cluster-params-overview. (line 13) * configure option, -with-low-memory: compilation-problems. (line 37) * configure script: source-configuration-options. (line 6) * configure, disable-grant-options option: source-configuration-options. (line 538) * configure, enable-community-features option: source-configuration-options. (line 545) * configure, enable-debug-sync option: source-configuration-options. (line 493) * configure, enable-profiling option: source-configuration-options. (line 551) * configure, enable-thread-safe-client option: source-configuration-options. (line 513) * configure, localstatedir option: source-configuration-options. (line 349) * configure, prefix option: source-configuration-options. (line 349) * configure, running after prior invocation: compilation-problems. (line 14) * configure, with-big-tables option: source-configuration-options. (line 528) * configure, with-charset option: source-configuration-options. (line 434) * configure, with-client-ldflags option: source-configuration-options. (line 389) * configure, with-collation option: source-configuration-options. (line 434) * configure, with-debug option: source-configuration-options. (line 476) * configure, with-embedded-server option: source-configuration-options. (line 346) * configure, with-extra-charsets option: source-configuration-options. (line 434) * configure, with-tcp-port option: source-configuration-options. (line 370) * configure, with-unix-socket-path option: source-configuration-options. (line 377) * configure, with-zlib-dir option: source-configuration-options. (line 519) * configure, without-server option: source-configuration-options. (line 332) * configuring backups, in MySQL Cluster: mysql-cluster-backup-configuration. (line 6) * configuring MySQL Cluster <1>: mysql-cluster-programs-ndb-mgmd. (line 495) * configuring MySQL Cluster <2>: mysql-cluster-programs-mysqld. (line 49) * configuring MySQL Cluster <3>: mysql-cluster-configuration. (line 14) * configuring MySQL Cluster: mysql-cluster-installation. (line 16) * Configuring MySQL Cluster (concepts): mysql-cluster-basics. (line 6) * conflict resolution, and ndb_replication system table: mysql-cluster-replication-conflict-resolution. (line 149) * conflict resolution, enabling: mysql-cluster-replication-conflict-resolution. (line 141) * conflict resolution, in MySQL Cluster Replication: mysql-cluster-replication-conflict-resolution. (line 6) * conflict resolution, mysqld startup options: mysql-cluster-replication-conflict-resolution. (line 83) * connect command, mysql: mysql-commands. (line 75) * Connect Out, thread command: thread-commands. (line 25) * Connect, thread command: thread-commands. (line 21) * connect_timeout system variable: server-system-variables. (line 1087) * connect_timeout variable <1>: mysqladmin. (line 446) * connect_timeout variable: mysql-command-options. (line 611) * Connecting to master, thread state: slave-io-thread-states. (line 16) * connecting, remotely with SSH: windows-and-ssh. (line 6) * connecting, to the server <1>: connecting. (line 6) * connecting, to the server: connecting-disconnecting. (line 6) * connecting, verification: connection-access. (line 6) * CONNECTION Events (MySQL Cluster): mysql-cluster-log-events. (line 20) * connection, aborted: communication-errors. (line 6) * CONNECTION_ID(): information-functions. (line 125) * Connector/C: connectors-apis. (line 24) * Connector/C++: connectors-apis. (line 24) * Connector/JDBC: connectors-apis. (line 24) * Connector/MXJ: connectors-apis. (line 24) * Connector/NET <1>: connector-net. (line 18) * Connector/NET: connectors-apis. (line 24) * Connector/NET, reporting problems: connect-net-support. (line 12) * Connector/ODBC <1>: connector-odbc. (line 17) * Connector/ODBC: connectors-apis. (line 24) * Connector/ODBC, Borland: connector-odbc-usagenotes-apptips-borland. (line 12) * Connector/ODBC, Borland Database Engine: connector-odbc-usagenotes-apptips-borland. (line 12) * Connector/ODBC, reporting problems: connector-odbc-support. (line 14) * Connector/OpenOffice.org: connectors-apis. (line 24) * Connectors, MySQL: connectors-apis. (line 24) * connectstring: mysql-cluster-connectstring. (line 6) * console option, mysqld: server-options. (line 390) * const table, optimizer <1>: select. (line 493) * const table, optimizer: explain-output. (line 94) * constant table: where-optimizations. (line 50) * constraints: constraints. (line 12) * CONSTRAINTS, INFORMATION_SCHEMA table: table-constraints-table. (line 6) * Contains(): functions-that-test-spatial-relationships-between-geometries. (line 17) * contributing companies, list of: supporters. (line 6) * contributors, list of: contributors. (line 6) * control flow functions: control-flow-functions. (line 6) * CONV(): mathematical-functions. (line 140) * conventions, syntax: manual-conventions. (line 8) * conventions, typographical: manual-conventions. (line 8) * CONVERT: cast-functions. (line 45) * CONVERT TO: alter-table. (line 463) * CONVERT_TZ(): date-and-time-functions. (line 161) * converting HEAP to MyISAM, thread state: general-thread-states. (line 44) * ConvexHull(): spatial-operators. (line 16) * copy option, mysqlaccess: mysqlaccess. (line 82) * copy to tmp table, thread state: general-thread-states. (line 49) * copying databases: copying-databases. (line 6) * copying tables <1>: create-table-select. (line 6) * copying tables: create-table. (line 1235) * Copying to group table, thread state: general-thread-states. (line 55) * Copying to tmp table on disk, thread state: general-thread-states. (line 64) * Copying to tmp table, thread state: general-thread-states. (line 60) * core-file option, mysqld: server-options. (line 402) * core-file-size option, mysqld_safe: mysqld-safe. (line 139) * correct-checksum option, myisamchk: myisamchk-repair-options. (line 19) * correlated subqueries: correlated-subqueries. (line 6) * COS(): mathematical-functions. (line 160) * COT(): mathematical-functions. (line 167) * count option, myisam_ftdump: myisam-ftdump. (line 62) * count option, mysqladmin: mysqladmin. (line 323) * count option, mysqlshow: mysqlshow. (line 135) * COUNT(): group-by-functions. (line 92) * COUNT(DISTINCT): group-by-functions. (line 122) * counters, ndbinfo table: mysql-cluster-ndbinfo-counters. (line 6) * counting, table rows: counting-rows. (line 6) * CR_SERVER_GONE_ERROR: gone-away. (line 6) * CR_SERVER_LOST_ERROR: gone-away. (line 6) * crash: debugging-server. (line 16) * crash, recovery: myisam-crash-recovery. (line 6) * crash, repeated: crashing. (line 6) * crash, replication: replication-features-shutdowns. (line 6) * crash-me: mysql-benchmarks. (line 43) * crash-me program <1>: mysql-benchmarks. (line 6) * crash-me program: portability. (line 6) * CRC32(): mathematical-functions. (line 176) * CREATE ... IF NOT EXISTS, and replication: replication-features-create-if-not-exists. (line 6) * CREATE DATABASE: create-database. (line 6) * Create DB, thread command: thread-commands. (line 29) * CREATE EVENT: create-event. (line 6) * CREATE EVENT, and replication: replication-features-invoked. (line 49) * CREATE FUNCTION <1>: create-function-udf. (line 6) * CREATE FUNCTION: create-procedure. (line 6) * CREATE INDEX: create-index. (line 6) * CREATE LOGFILE GROUP: create-logfile-group. (line 6) * CREATE NODEGROUP command (MySQL Cluster): mysql-cluster-mgm-client-commands. (line 191) * create option, mysqlslap: mysqlslap. (line 283) * CREATE PROCEDURE: create-procedure. (line 6) * CREATE SCHEMA: create-database. (line 6) * CREATE SERVER: create-server. (line 6) * CREATE TABLE: create-table. (line 11) * CREATE TABLE ... SELECT, and replication: replication-features-create-select. (line 6) * CREATE TABLE, DIRECTORY options, and replication: replication-features-directory. (line 6) * CREATE TABLESPACE: create-tablespace. (line 6) * CREATE TRIGGER: create-trigger. (line 6) * CREATE USER: create-user. (line 6) * CREATE VIEW: create-view. (line 6) * create-and-drop-schema option, mysqlslap: mysqlslap. (line 288) * create-options option, mysqldump: mysqldump. (line 453) * create-schema option, mysqlslap: mysqlslap. (line 294) * Creating delayed handler, thread state: delayed-insert-thread-states. (line 22) * Creating index, thread state: general-thread-states. (line 72) * Creating sort index, thread state: general-thread-states. (line 77) * Creating table from master dump, thread state: slave-connection-thread-states. (line 14) * creating table, thread state: general-thread-states. (line 82) * Creating tmp table, thread state: general-thread-states. (line 87) * creating user accounts: create-user. (line 6) * creating, bug reports: bug-reports. (line 6) * creating, database: create-database. (line 6) * creating, databases: database-use. (line 13) * creating, default startup options: option-files. (line 11) * creating, function: create-function-udf. (line 6) * creating, schema: create-database. (line 6) * creating, tables: creating-tables. (line 6) * CROSS JOIN: join. (line 6) * Crosses(): functions-that-test-spatial-relationships-between-geometries. (line 22) * CSV data, reading <1>: select. (line 402) * CSV data, reading: load-data. (line 327) * csv option, mysqlslap: mysqlslap. (line 306) * CSV storage engine <1>: csv-storage-engine. (line 11) * CSV storage engine: storage-engines. (line 23) * CURDATE(): date-and-time-functions. (line 190) * CURRENT_DATE: date-and-time-functions. (line 201) * CURRENT_TIME: date-and-time-functions. (line 217) * CURRENT_TIMESTAMP: date-and-time-functions. (line 221) * CURRENT_USER(): information-functions. (line 134) * Cursors: cursors. (line 13) * CURTIME(): date-and-time-functions. (line 205) * CXX environment variable <1>: environment-variables. (line 18) * CXX environment variable <2>: compilation-problems. (line 65) * CXX environment variable: source-configuration-options. (line 397) * CXXFLAGS environment variable <1>: environment-variables. (line 18) * CXXFLAGS environment variable: compilation-problems. (line 88) * daemon plugins: daemon-plugins. (line 6) * Daemon, thread command: thread-commands. (line 33) * DATA DIRECTORY, and replication: replication-features-directory. (line 6) * data node (MySQL Cluster), defined: mysql-cluster-basics. (line 6) * data nodes (MySQL Cluster) <1>: mysql-cluster-programs-ndbmtd. (line 6) * data nodes (MySQL Cluster): mysql-cluster-programs-ndbd. (line 6) * Data truncation with CJK characters: faqs-cjk. (line 6) * data type, BIGINT: numeric-type-overview. (line 125) * data type, BINARY <1>: binary-varbinary. (line 6) * data type, BINARY: string-type-overview. (line 151) * data type, BIT: numeric-type-overview. (line 35) * data type, BLOB <1>: blob. (line 6) * data type, BLOB: string-type-overview. (line 180) * data type, BOOL <1>: other-vendor-data-types. (line 6) * data type, BOOL: numeric-type-overview. (line 45) * data type, BOOLEAN <1>: other-vendor-data-types. (line 6) * data type, BOOLEAN: numeric-type-overview. (line 45) * data type, CHAR <1>: string-types. (line 14) * data type, CHAR: string-type-overview. (line 89) * data type, CHAR VARYING: string-type-overview. (line 121) * data type, CHARACTER: string-type-overview. (line 89) * data type, CHARACTER VARYING: string-type-overview. (line 121) * data type, DATE <1>: datetime. (line 10) * data type, DATE: date-and-time-type-overview. (line 16) * data type, DATETIME <1>: datetime. (line 10) * data type, DATETIME: date-and-time-type-overview. (line 23) * data type, DEC: numeric-type-overview. (line 246) * data type, DECIMAL <1>: precision-math. (line 14) * data type, DECIMAL: numeric-type-overview. (line 230) * data type, DOUBLE: numeric-type-overview. (line 190) * data type, DOUBLE PRECISION: numeric-type-overview. (line 207) * data type, ENUM <1>: enum. (line 6) * data type, ENUM: string-type-overview. (line 239) * data type, FIXED: numeric-type-overview. (line 246) * data type, FLOAT: numeric-type-overview. (line 170) * data type, GEOMETRY: mysql-spatial-datatypes. (line 6) * data type, GEOMETRYCOLLECTION: mysql-spatial-datatypes. (line 6) * data type, INT: numeric-type-overview. (line 116) * data type, INTEGER: numeric-type-overview. (line 121) * data type, LINESTRING: mysql-spatial-datatypes. (line 6) * data type, LONG: blob. (line 6) * data type, LONGBLOB: string-type-overview. (line 218) * data type, LONGTEXT: string-type-overview. (line 228) * data type, MEDIUMBLOB: string-type-overview. (line 203) * data type, MEDIUMINT: numeric-type-overview. (line 111) * data type, MEDIUMTEXT: string-type-overview. (line 210) * data type, MULTILINESTRING: mysql-spatial-datatypes. (line 6) * data type, MULTIPOINT: mysql-spatial-datatypes. (line 6) * data type, MULTIPOLYGON: mysql-spatial-datatypes. (line 6) * data type, NATIONAL CHAR: string-type-overview. (line 89) * data type, NATIONAL VARCHAR: string-type-overview. (line 121) * data type, NCHAR: string-type-overview. (line 89) * data type, NUMERIC: numeric-type-overview. (line 246) * data type, NVARCHAR: string-type-overview. (line 121) * data type, POINT: mysql-spatial-datatypes. (line 6) * data type, POLYGON: mysql-spatial-datatypes. (line 6) * data type, REAL: numeric-type-overview. (line 207) * data type, SET <1>: set. (line 6) * data type, SET: string-type-overview. (line 248) * data type, SMALLINT: numeric-type-overview. (line 106) * data type, TEXT <1>: blob. (line 6) * data type, TEXT: string-type-overview. (line 191) * data type, TIME <1>: time. (line 6) * data type, TIME: date-and-time-type-overview. (line 63) * data type, TIMESTAMP <1>: datetime. (line 10) * data type, TIMESTAMP: date-and-time-type-overview. (line 31) * data type, TINYBLOB: string-type-overview. (line 165) * data type, TINYINT: numeric-type-overview. (line 40) * data type, TINYTEXT: string-type-overview. (line 172) * data type, VARBINARY <1>: binary-varbinary. (line 6) * data type, VARBINARY: string-type-overview. (line 158) * data type, VARCHAR <1>: string-types. (line 14) * data type, VARCHAR: string-type-overview. (line 121) * data type, VARCHARACTER: string-type-overview. (line 121) * data type, YEAR <1>: year. (line 6) * data type, YEAR: date-and-time-type-overview. (line 70) * data types: data-types. (line 30) * data types, C API: c. (line 25) * data types, overview: data-type-overview. (line 13) * data, importing <1>: mysqlimport. (line 6) * data, importing: batch-commands. (line 6) * data, loading into tables: loading-tables. (line 6) * data, retrieving: retrieving-data. (line 18) * data, size: data-size. (line 6) * data-file-length option, myisamchk: myisamchk-repair-options. (line 23) * Database information, obtaining: show. (line 51) * database metadata: information-schema. (line 37) * database names, case sensitivity: identifier-case-sensitivity. (line 6) * database names, case-sensitivity: extensions-to-ansi. (line 38) * database option, mysql: mysql-command-options. (line 219) * database option, mysqlbinlog: mysqlbinlog. (line 242) * database option, ndb_show_tables: mysql-cluster-programs-ndb-show-tables. (line 35) * DATABASE(): information-functions. (line 198) * database, altering: alter-database. (line 6) * database, creating: create-database. (line 6) * database, deleting: drop-database. (line 6) * databases option, mysqlcheck: mysqlcheck. (line 260) * databases option, mysqldump: mysqldump. (line 458) * databases, backups: backup-and-recovery. (line 15) * databases, copying: copying-databases. (line 6) * databases, creating: database-use. (line 13) * databases, defined: what-is-mysql. (line 25) * databases, displaying: mysqlshow. (line 6) * databases, dumping <1>: mysqlhotcopy. (line 6) * databases, dumping: mysqldump. (line 6) * databases, information about: getting-information. (line 6) * databases, names: identifiers. (line 13) * databases, replicating: replication. (line 13) * databases, selecting: creating-database. (line 6) * databases, symbolic links: symbolic-links-to-databases. (line 6) * databases, using: database-use. (line 13) * DataDir <1>: mysql-cluster-ndbd-definition. (line 286) * DataDir: mysql-cluster-mgm-definition. (line 237) * datadir option, mysql.server: mysql-server. (line 40) * datadir option, mysql_install_db: mysql-install-db. (line 61) * datadir option, mysql_upgrade: mysql-upgrade. (line 125) * datadir option, mysqld: server-options. (line 431) * datadir option, mysqld_safe: mysqld-safe. (line 144) * datadir system variable: server-system-variables. (line 1120) * DataJunction: connector-odbc-usagenotes-apptips-datajunction. (line 6) * DataMemory <1>: mysql-cluster-config-lcp-params. (line 6) * DataMemory: mysql-cluster-ndbd-definition. (line 364) * DATE: using-date. (line 6) * date and time functions: date-and-time-functions. (line 6) * Date and Time types: date-and-time-types. (line 13) * date calculations: date-calculations. (line 6) * DATE columns, problems: using-date. (line 6) * DATE data type <1>: datetime. (line 10) * DATE data type: date-and-time-type-overview. (line 16) * date functions, Y2K compliance: y2k-issues. (line 6) * date types: storage-requirements. (line 125) * date types, Y2K issues: y2k-issues. (line 6) * date values: date-and-time-values. (line 6) * date values, problems: datetime. (line 167) * DATE(): date-and-time-functions. (line 226) * DATE_ADD(): date-and-time-functions. (line 245) * date_format system variable: server-system-variables. (line 1141) * DATE_FORMAT(): date-and-time-functions. (line 402) * DATE_SUB(): date-and-time-functions. (line 245) * DATEDIFF(): date-and-time-functions. (line 233) * dates, used with partitioning: partitioning-types. (line 49) * dates, used with partitioning (examples) <1>: partitioning-pruning. (line 72) * dates, used with partitioning (examples) <2>: partitioning-subpartitions. (line 42) * dates, used with partitioning (examples) <3>: partitioning-hash. (line 49) * dates, used with partitioning (examples): partitioning-range. (line 127) * DATETIME data type <1>: datetime. (line 10) * DATETIME data type: date-and-time-type-overview. (line 23) * datetime_format system variable: server-system-variables. (line 1145) * DAY(): date-and-time-functions. (line 487) * DAYNAME(): date-and-time-functions. (line 491) * DAYOFMONTH(): date-and-time-functions. (line 500) * DAYOFWEEK(): date-and-time-functions. (line 509) * DAYOFYEAR(): date-and-time-functions. (line 518) * db option, mysqlaccess: mysqlaccess. (line 86) * db table, sorting: request-access. (line 51) * DB2 SQL mode: server-sql-mode. (line 465) * DBI interface: apis-perl. (line 6) * DBI->quote: string-syntax. (line 142) * DBI->trace: using-gdb-on-mysqld. (line 89) * DBI/DBD interface: apis-perl. (line 6) * DBI_TRACE environment variable <1>: using-gdb-on-mysqld. (line 89) * DBI_TRACE environment variable: environment-variables. (line 18) * DBI_USER environment variable: environment-variables. (line 18) * DBUG package: the-dbug-package. (line 6) * DEALLOCATE PREPARE <1>: deallocate-prepare. (line 6) * DEALLOCATE PREPARE: sql-syntax-prepared-statements. (line 13) * debug option, comp_err: comp-err. (line 35) * debug option, make_win_bin_dist: make-win-bin-dist. (line 36) * debug option, my_print_defaults: my-print-defaults. (line 35) * debug option, myisamchk: myisamchk-general-options. (line 21) * debug option, myisampack: myisampack. (line 61) * debug option, mysql: mysql-command-options. (line 223) * debug option, mysqlaccess: mysqlaccess. (line 90) * debug option, mysqladmin: mysqladmin. (line 328) * debug option, mysqlbinlog: mysqlbinlog. (line 327) * debug option, mysqlcheck: mysqlcheck. (line 268) * debug option, mysqld: server-options. (line 451) * debug option, mysqldump: mysqldump. (line 467) * debug option, mysqldumpslow: mysqldumpslow. (line 53) * debug option, mysqlhotcopy: mysqlhotcopy. (line 104) * debug option, mysqlimport: mysqlimport. (line 160) * debug option, mysqlmanager: instance-manager-command-options. (line 60) * debug option, mysqlshow: mysqlshow. (line 140) * debug option, mysqlslap: mysqlslap. (line 312) * debug system variable: server-system-variables. (line 1149) * Debug, thread command: thread-commands. (line 38) * debug-check option, mysql: mysql-command-options. (line 228) * debug-check option, mysql_upgrade: mysql-upgrade. (line 130) * debug-check option, mysqladmin: mysqladmin. (line 334) * debug-check option, mysqlbinlog: mysqlbinlog. (line 333) * debug-check option, mysqlcheck: mysqlcheck. (line 273) * debug-check option, mysqldump: mysqldump. (line 473) * debug-check option, mysqlimport: mysqlimport. (line 165) * debug-check option, mysqlshow: mysqlshow. (line 145) * debug-check option, mysqlslap: mysqlslap. (line 318) * debug-info option, comp_err: comp-err. (line 40) * debug-info option, mysql: mysql-command-options. (line 233) * debug-info option, mysql_upgrade: mysql-upgrade. (line 135) * debug-info option, mysqladmin: mysqladmin. (line 339) * debug-info option, mysqlbinlog: mysqlbinlog. (line 338) * debug-info option, mysqlcheck: mysqlcheck. (line 278) * debug-info option, mysqldump: mysqldump. (line 478) * debug-info option, mysqlimport: mysqlimport. (line 170) * debug-info option, mysqlshow: mysqlshow. (line 150) * debug-info option, mysqlslap: mysqlslap. (line 323) * debug-sync-timeout option, mysqld: server-options. (line 484) * debug_sync system variable: server-system-variables. (line 1201) * debugging support: source-configuration-options. (line 6) * debugging, client: debugging-client. (line 6) * debugging, server: debugging-server. (line 16) * DEC data type: numeric-type-overview. (line 246) * decimal arithmetic: precision-math. (line 14) * DECIMAL data type <1>: precision-math. (line 14) * DECIMAL data type: numeric-type-overview. (line 230) * decimal point: data-types. (line 38) * DECLARE: declare. (line 6) * DECODE(): encryption-functions. (line 164) * decode_bits myisamchk variable: myisamchk-general-options. (line 53) * default host name: connecting. (line 6) * default installation location: installation-layouts. (line 6) * default options: option-files. (line 11) * DEFAULT value clause <1>: create-table. (line 301) * DEFAULT value clause: data-type-defaults. (line 6) * default values <1>: insert. (line 70) * default values <2>: create-table. (line 301) * default values <3>: data-type-defaults. (line 6) * default values: design-limitations. (line 20) * default values, BLOB and TEXT columns: blob. (line 53) * default values, explicit: data-type-defaults. (line 6) * default values, implicit: data-type-defaults. (line 6) * default values, suppression: constraint-invalid-data. (line 6) * DEFAULT(): miscellaneous-functions. (line 29) * DEFAULT, constraint: constraint-invalid-data. (line 6) * default, privileges: default-privileges. (line 6) * default-character-set option, mysql: mysql-command-options. (line 241) * default-character-set option, mysqladmin: mysqladmin. (line 344) * default-character-set option, mysqlcheck: mysqlcheck. (line 283) * default-character-set option, mysqld: server-options. (line 512) * default-character-set option, mysqldump: mysqldump. (line 483) * default-character-set option, mysqlimport: mysqlimport. (line 175) * default-character-set option, mysqlshow: mysqlshow. (line 155) * default-collation option, mysqld: server-options. (line 531) * default-mysqld-path option, mysqlmanager: instance-manager-command-options. (line 65) * default-storage-engine option, mysqld: server-options. (line 548) * default-table-type option, mysqld: server-options. (line 562) * default-time-zone option, mysqld: server-options. (line 579) * default_week_format system variable: server-system-variables. (line 1239) * DefaultOperationRedoProblemAction, API and SQL nodes: mysql-cluster-api-definition. (line 302) * defaults, embedded: libmysqld-options. (line 6) * defaults-extra-file option: option-file-options. (line 22) * defaults-extra-file option, my_print_defaults: my-print-defaults. (line 41) * defaults-extra-file option, mysqld_multi: mysqld-multi. (line 68) * defaults-extra-file option, mysqld_safe: mysqld-safe. (line 148) * defaults-file option: option-file-options. (line 29) * defaults-file option, my_print_defaults: my-print-defaults. (line 31) * defaults-file option, mysqld_multi: mysqld-multi. (line 66) * defaults-file option, mysqld_safe: mysqld-safe. (line 155) * defaults-file option, mysqlmanager: instance-manager-command-options. (line 74) * defaults-group-suffix option: option-file-options. (line 35) * defaults-group-suffix option, my_print_defaults: my-print-defaults. (line 48) * DEGREES(): mathematical-functions. (line 188) * delay-key-write option, mysqld <1>: myisam-start. (line 42) * delay-key-write option, mysqld: server-options. (line 595) * delay_key_write system variable: server-system-variables. (line 1261) * DELAYED: insert-delayed. (line 6) * Delayed insert, thread command: thread-commands. (line 42) * delayed inserts, thread states: delayed-insert-thread-states. (line 6) * DELAYED, when ignored: insert. (line 226) * delayed-insert option, mysqldump: mysqldump. (line 494) * delayed_insert_limit: insert-delayed. (line 123) * delayed_insert_limit system variable: server-system-variables. (line 1308) * delayed_insert_timeout system variable: server-system-variables. (line 1340) * delayed_queue_size system variable: server-system-variables. (line 1361) * DELETE: delete. (line 6) * delete option, mysqlimport: mysqlimport. (line 180) * DELETE, and MySQL Cluster: mysql-cluster-limitations-limits. (line 9) * delete-master-logs option, mysqldump: mysqldump. (line 499) * deleting from main table, thread state: general-thread-states. (line 94) * deleting from reference tables, thread state: general-thread-states. (line 100) * deleting, database: drop-database. (line 6) * deleting, foreign key <1>: innodb-foreign-key-constraints. (line 162) * deleting, foreign key: alter-table. (line 428) * deleting, function: drop-function-udf. (line 6) * deleting, index <1>: drop-index. (line 6) * deleting, index: alter-table. (line 314) * deleting, primary key: alter-table. (line 329) * deleting, rows: deleting-from-related-tables. (line 6) * deleting, schema: drop-database. (line 6) * deleting, table: drop-table. (line 6) * deleting, user <1>: drop-user. (line 6) * deleting, user: removing-users. (line 6) * deleting, users <1>: drop-user. (line 6) * deleting, users: removing-users. (line 6) * deletion, mysql.sock: problems-with-mysql-sock. (line 6) * delimiter command, mysql: mysql-commands. (line 82) * delimiter option, mysql: mysql-command-options. (line 255) * delimiter option, mysqlslap: mysqlslap. (line 328) * delimiter option, ndb_select_all: mysql-cluster-programs-ndb-select-all. (line 49) * Delphi: connector-odbc-usagenotes-apptips-borland-delphi. (line 6) * derived tables: from-clause-subqueries. (line 6) * des-key-file option, mysqld: server-options. (line 629) * DES_DECRYPT(): encryption-functions. (line 169) * DES_ENCRYPT(): encryption-functions. (line 190) * DESC: describe. (line 6) * descending option, ndb_select_all: mysql-cluster-programs-ndb-select-all. (line 34) * DESCRIBE <1>: describe. (line 6) * DESCRIBE: getting-information. (line 6) * description option, myisamchk: myisamchk-other-options. (line 22) * design, issues: bugs. (line 6) * design, limitations: design-limitations. (line 6) * detach option, mysqlslap: mysqlslap. (line 333) * development of MySQL Cluster: mysql-cluster-development. (line 16) * development source tree: installing-development-tree. (line 6) * Difference(): spatial-operators. (line 21) * digits: data-types. (line 38) * Dimension(): general-geometry-property-functions. (line 9) * directory structure, default: installation-layouts. (line 6) * disable named command, mysql: mysql-command-options. (line 260) * disable-grant-options option, configure: source-configuration-options. (line 538) * disable-keys option, mysqldump: mysqldump. (line 506) * disable-log-bin option, mysqlbinlog: mysqlbinlog. (line 343) * DISCARD TABLESPACE <1>: innodb-multiple-tablespaces. (line 59) * DISCARD TABLESPACE: alter-table. (line 439) * discard_or_import_tablespace, thread state: general-thread-states. (line 105) * disconnect-slave-event-count option, mysqld: replication-options-slave. (line 161) * disconnecting, from the server: connecting-disconnecting. (line 6) * Disjoint(): functions-that-test-spatial-relationships-between-geometries. (line 40) * Disk Data tables (MySQL Cluster): mysql-cluster-disk-data. (line 12) * disk full: full-disk. (line 6) * disk option, ndb_select_all: mysql-cluster-programs-ndb-select-all. (line 56) * disk performance: disk-issues. (line 6) * DiskCheckpointSpeed: mysql-cluster-ndbd-definition. (line 2366) * DiskCheckpointSpeedInRestart: mysql-cluster-ndbd-definition. (line 2389) * DiskIOThreadPool: mysql-cluster-ndbd-definition. (line 3411) * Diskless: mysql-cluster-ndbd-definition. (line 1621) * diskpagebuffer, ndbinfo table: mysql-cluster-ndbinfo-diskpagebuffer. (line 6) * DiskPageBufferMemory: mysql-cluster-ndbd-definition. (line 3350) * disks, splitting data across: windows-symbolic-links. (line 6) * DiskSyncSize: mysql-cluster-ndbd-definition. (line 2339) * display size: data-types. (line 32) * display triggers: show-triggers. (line 6) * display width: data-types. (line 32) * displaying, database information: mysqlshow. (line 6) * displaying, information, Cardinality: show-index. (line 41) * displaying, information, Collation: show-index. (line 36) * displaying, information, SHOW <1>: show-tables. (line 6) * displaying, information, SHOW <2>: show-open-tables. (line 6) * displaying, information, SHOW <3>: show-index. (line 6) * displaying, information, SHOW <4>: show-columns. (line 6) * displaying, information, SHOW: show. (line 51) * displaying, table status: show-table-status. (line 6) * DISTINCT <1>: select. (line 469) * DISTINCT <2>: distinct-optimization. (line 6) * DISTINCT: selecting-columns. (line 43) * DISTINCT, AVG(): group-by-functions. (line 58) * DISTINCT, COUNT(): group-by-functions. (line 122) * DISTINCT, MAX(): group-by-functions. (line 191) * DISTINCT, MIN(): group-by-functions. (line 211) * DISTINCT, SUM(): group-by-functions. (line 262) * DISTINCTROW: select. (line 469) * distributed privileges (MySQL Cluster): mysql-cluster-privilege-distribution. (line 6) * distributed privileges (MySQL Cluster), and NDB API applications: mysql-cluster-privilege-distribution. (line 182) * DIV: arithmetic-functions. (line 108) * div_precision_increment system variable: server-system-variables. (line 1393) * division (/): arithmetic-functions. (line 92) * DNS: dns. (line 6) * DO: do. (line 6) * DocBook XML, documentation source format: manual-info. (line 31) * Documentation, in Chinese: faqs-cjk. (line 6) * Documentation, in Japanese: faqs-cjk. (line 6) * Documentation, in Korean: faqs-cjk. (line 6) * Documenters, list of: documenters-translators. (line 6) * DOUBLE data type: numeric-type-overview. (line 190) * DOUBLE PRECISION data type: numeric-type-overview. (line 207) * double quote (\"): string-syntax. (line 58) * downgrades, MySQL Cluster <1>: mysql-cluster-rolling-restart. (line 6) * downgrades, MySQL Cluster: mysql-cluster-upgrade-downgrade. (line 12) * downgrading <1>: downgrading. (line 10) * downgrading: upgrading-downgrading. (line 14) * downloading: getting-mysql. (line 6) * DRBD license: faqs-drbd. (line 6) * drbd, FAQ <1>: faqs-drbd. (line 6) * drbd, FAQ: faqs-mysql-drbd-heartbeat. (line 19) * DROP ... IF EXISTS, and replication: replication-features-drop-if-exists. (line 6) * DROP DATABASE: drop-database. (line 6) * Drop DB, thread command: thread-commands. (line 46) * DROP EVENT: drop-event. (line 6) * DROP FOREIGN KEY <1>: innodb-foreign-key-constraints. (line 162) * DROP FOREIGN KEY: alter-table. (line 428) * DROP FUNCTION <1>: drop-function-udf. (line 6) * DROP FUNCTION: drop-procedure. (line 6) * DROP INDEX <1>: drop-index. (line 6) * DROP INDEX: alter-table. (line 314) * DROP LOGFILE GROUP: drop-logfile-group. (line 6) * DROP NODEGROUP command (MySQL Cluster): mysql-cluster-mgm-client-commands. (line 214) * DROP PREPARE: deallocate-prepare. (line 6) * DROP PRIMARY KEY: alter-table. (line 329) * DROP PROCEDURE: drop-procedure. (line 6) * DROP SCHEMA: drop-database. (line 6) * DROP SERVER: drop-server. (line 6) * DROP TABLE: drop-table. (line 6) * DROP TABLE, and MySQL Cluster: mysql-cluster-limitations-limits. (line 9) * DROP TABLESPACE: drop-tablespace. (line 6) * DROP TRIGGER: drop-trigger. (line 6) * DROP USER: drop-user. (line 6) * DROP VIEW: drop-view. (line 6) * drop-user option, mysqlmanager: instance-manager-command-options. (line 86) * dropping, user <1>: drop-user. (line 6) * dropping, user: removing-users. (line 6) * dryrun option, mysqlhotcopy: mysqlhotcopy. (line 108) * DUAL: select. (line 66) * dump option, myisam_ftdump: myisam-ftdump. (line 66) * dump-date option, mysqldump: mysqldump. (line 515) * DUMPFILE: select. (line 410) * dumping, databases and tables <1>: mysqlhotcopy. (line 6) * dumping, databases and tables: mysqldump. (line 6) * dynamic table characteristics: dynamic-format. (line 6) * edit command, mysql: mysql-commands. (line 117) * edit-user option, mysqlmanager: instance-manager-command-options. (line 91) * ego command, mysql: mysql-commands. (line 126) * Eiffel Wrapper: apis-eiffel. (line 6) * ELT(): string-functions. (line 231) * email lists: mailing-lists. (line 10) * embedded MySQL server library: libmysqld. (line 14) * embedded option, make_win_bin_dist: make-win-bin-dist. (line 41) * embedded option, mysql_config: mysql-config. (line 24) * enable-community-features option, configure: source-configuration-options. (line 545) * enable-debug-sync option, configure: source-configuration-options. (line 493) * enable-named-pipe option, mysqld: server-options. (line 639) * enable-profiling option, configure: source-configuration-options. (line 551) * enable-pstack option, mysqld: server-options. (line 657) * enable-thread-safe-client option, configure: source-configuration-options. (line 513) * ENCODE(): encryption-functions. (line 241) * ENCRYPT(): encryption-functions. (line 251) * encryption: secure-basics. (line 18) * encryption functions: encryption-functions. (line 6) * END: begin-end. (line 6) * end, thread state: general-thread-states. (line 110) * EndPoint(): linestring-property-functions. (line 10) * engine option, mysqlslap: mysqlslap. (line 339) * engine_condition_pushdown system variable: server-system-variables. (line 1432) * ENGINES, INFORMATION_SCHEMA table: engines-table. (line 6) * ENTER SINGLE USER MODE command (MySQL Cluster): mysql-cluster-mgm-client-commands. (line 158) * entering, queries: entering-queries. (line 6) * ENUM data type <1>: enum. (line 6) * ENUM data type: string-type-overview. (line 239) * ENUM, size: storage-requirements. (line 252) * Envelope(): general-geometry-property-functions. (line 22) * environment variable, CC <1>: environment-variables. (line 18) * environment variable, CC <2>: compilation-problems. (line 88) * environment variable, CC: source-configuration-options. (line 397) * environment variable, CFLAGS <1>: environment-variables. (line 18) * environment variable, CFLAGS: compilation-problems. (line 88) * environment variable, CXX <1>: environment-variables. (line 18) * environment variable, CXX <2>: compilation-problems. (line 65) * environment variable, CXX: source-configuration-options. (line 397) * environment variable, CXXFLAGS <1>: environment-variables. (line 18) * environment variable, CXXFLAGS: compilation-problems. (line 88) * environment variable, DBI_TRACE <1>: using-gdb-on-mysqld. (line 89) * environment variable, DBI_TRACE: environment-variables. (line 18) * environment variable, DBI_USER: environment-variables. (line 18) * environment variable, HOME <1>: mysql-history-file. (line 6) * environment variable, HOME: environment-variables. (line 18) * environment variable, LD_LIBRARY_PATH: perl-support-problems. (line 20) * environment variable, LD_RUN_PATH <1>: perl-support-problems. (line 20) * environment variable, LD_RUN_PATH <2>: environment-variables. (line 18) * environment variable, LD_RUN_PATH: solaris-installation-source. (line 97) * environment variable, MYSQL_DEBUG <1>: debugging-client. (line 10) * environment variable, MYSQL_DEBUG <2>: programs-overview. (line 317) * environment variable, MYSQL_DEBUG: environment-variables. (line 18) * environment variable, MYSQL_GROUP_SUFFIX: environment-variables. (line 18) * environment variable, MYSQL_HISTFILE <1>: mysql-history-file. (line 6) * environment variable, MYSQL_HISTFILE: environment-variables. (line 18) * environment variable, MYSQL_HOME: environment-variables. (line 18) * environment variable, MYSQL_HOST <1>: connecting. (line 231) * environment variable, MYSQL_HOST: environment-variables. (line 18) * environment variable, MYSQL_PS1: environment-variables. (line 18) * environment variable, MYSQL_PWD <1>: connecting. (line 231) * environment variable, MYSQL_PWD <2>: programs-overview. (line 317) * environment variable, MYSQL_PWD: environment-variables. (line 18) * environment variable, MYSQL_TCP_PORT <1>: multiple-server-clients. (line 27) * environment variable, MYSQL_TCP_PORT <2>: multiple-unix-servers. (line 68) * environment variable, MYSQL_TCP_PORT <3>: programs-overview. (line 317) * environment variable, MYSQL_TCP_PORT: environment-variables. (line 18) * environment variable, MYSQL_UNIX_PORT <1>: multiple-server-clients. (line 27) * environment variable, MYSQL_UNIX_PORT <2>: multiple-unix-servers. (line 68) * environment variable, MYSQL_UNIX_PORT <3>: programs-overview. (line 317) * environment variable, MYSQL_UNIX_PORT <4>: environment-variables. (line 18) * environment variable, MYSQL_UNIX_PORT: mysql-install-db-problems. (line 84) * environment variable, PATH <1>: invoking-programs. (line 48) * environment variable, PATH <2>: environment-variables. (line 18) * environment variable, PATH: unix-postinstallation. (line 68) * environment variable, TMPDIR <1>: temporary-files. (line 6) * environment variable, TMPDIR <2>: programs-overview. (line 317) * environment variable, TMPDIR <3>: environment-variables. (line 18) * environment variable, TMPDIR: mysql-install-db-problems. (line 84) * environment variable, TZ <1>: timezone-problems. (line 6) * environment variable, TZ: environment-variables. (line 18) * environment variable, UMASK <1>: file-permissions. (line 6) * environment variable, UMASK: environment-variables. (line 18) * environment variable, UMASK_DIR <1>: file-permissions. (line 20) * environment variable, UMASK_DIR: environment-variables. (line 18) * environment variable, USER <1>: connecting. (line 231) * environment variable, USER: environment-variables. (line 18) * environment variables <1>: access-denied. (line 101) * environment variables <2>: setting-environment-variables. (line 6) * environment variables: programs-overview. (line 314) * environment variables, CXX: compilation-problems. (line 75) * environment variables, list of: environment-variables. (line 6) * eq_ref join type, optimizer: explain-output. (line 111) * equal (=): comparison-operators. (line 64) * Equals(): functions-that-test-spatial-relationships-between-geometries. (line 45) * Errcode: perror. (line 6) * errno: perror. (line 6) * ERROR Events (MySQL Cluster): mysql-cluster-log-events. (line 196) * error logs (MySQL Cluster): mysql-cluster-programs-ndbd. (line 358) * error messages, can't find file: file-permissions. (line 6) * error messages, displaying: perror. (line 6) * error messages, languages: error-message-language. (line 6) * Error, thread command: thread-commands. (line 50) * error_count session variable: server-system-variables. (line 1472) * ERROR_FOR_DIVISION_BY_ZERO SQL mode: server-sql-mode. (line 117) * errors, access denied: error-access-denied. (line 6) * errors, and replication: replication-features-slaveerrors. (line 6) * errors, checking tables for: myisam-check. (line 6) * errors, common: problems. (line 17) * errors, directory checksum: solaris-installation. (line 11) * errors, handling for UDFs: udf-return-values. (line 6) * errors, in subqueries: subquery-errors. (line 6) * errors, known: bugs. (line 6) * errors, linking: c-api-linking-problems. (line 6) * errors, list of: common-errors. (line 28) * errors, lost connection: error-lost-connection. (line 6) * errors, reporting <1>: bug-reports. (line 6) * errors, reporting: introduction. (line 82) * errors, sources of information: error-sources. (line 6) * escape (\\): string-syntax. (line 64) * escape sequences, option files: option-files. (line 161) * escape sequences, strings: string-syntax. (line 6) * estimating, query performance: estimating-performance. (line 6) * event groups: set-global-sql-slave-skip-counter. (line 6) * event log format (MySQL Cluster): mysql-cluster-log-events. (line 6) * event logs (MySQL Cluster) <1>: mysql-cluster-logging-management-commands. (line 6) * event logs (MySQL Cluster): mysql-cluster-event-reports. (line 12) * Event Scheduler: events. (line 15) * event scheduler: stored-programs-views. (line 16) * Event Scheduler, altering events: alter-event. (line 6) * Event Scheduler, and MySQL privileges: events-privileges. (line 6) * Event Scheduler, and mysqladmin debug: events-status-info. (line 6) * Event Scheduler, and replication: replication-features-invoked. (line 6) * Event Scheduler, and SHOW PROCESSLIST: events-configuration. (line 29) * Event Scheduler, concepts: events-overview. (line 6) * Event Scheduler, creating events: create-event. (line 6) * Event Scheduler, dropping events: drop-event. (line 6) * Event Scheduler, enabling and disabling: events-configuration. (line 12) * Event Scheduler, event metadata: events-metadata. (line 6) * Event Scheduler, obtaining status information <1>: events-status-info. (line 6) * Event Scheduler, obtaining status information: show-scheduler-status. (line 6) * Event Scheduler, SQL statements: events-syntax. (line 6) * Event Scheduler, starting and stopping: events-configuration. (line 12) * event scheduler, thread states: event-scheduler-thread-states. (line 6) * Event Scheduler, time representation: events-metadata. (line 21) * event severity levels (MySQL Cluster): mysql-cluster-logging-management-commands. (line 55) * event types (MySQL Cluster) <1>: mysql-cluster-log-events. (line 20) * event types (MySQL Cluster): mysql-cluster-event-reports. (line 49) * event, restrictions: stored-program-restrictions. (line 6) * event-scheduler option, mysqld: server-options. (line 699) * event_scheduler system variable: server-system-variables. (line 1478) * events <1>: events. (line 15) * events: stored-programs-views. (line 16) * events option, mysqldump: mysqldump. (line 529) * events, altering: alter-event. (line 6) * events, creating: create-event. (line 6) * events, dropping: drop-event. (line 6) * EVENTS, INFORMATION_SCHEMA table <1>: events-table. (line 6) * EVENTS, INFORMATION_SCHEMA table: events-privileges. (line 71) * events, metadata: events-metadata. (line 6) * events, status variables: events-privileges. (line 184) * exact-value literals: precision-math. (line 14) * example option, mysqld_multi: mysqld-multi. (line 114) * EXAMPLE storage engine <1>: example-storage-engine. (line 6) * EXAMPLE storage engine: storage-engines. (line 23) * examples, compressed tables: myisampack. (line 122) * examples, myisamchk output: myisamchk-table-info. (line 6) * examples, queries: examples. (line 18) * exe-suffix option, make_win_bin_dist: make-win-bin-dist. (line 46) * EXECUTE <1>: execute. (line 6) * EXECUTE: sql-syntax-prepared-statements. (line 13) * execute option, mysql: mysql-command-options. (line 268) * Execute, thread command: thread-commands. (line 52) * ExecuteOnComputer <1>: mysql-cluster-api-definition. (line 92) * ExecuteOnComputer <2>: mysql-cluster-ndbd-definition. (line 109) * ExecuteOnComputer: mysql-cluster-mgm-definition. (line 83) * executing SQL statements from text files <1>: batch-commands. (line 6) * executing SQL statements from text files: batch-mode. (line 6) * executing, thread state: general-thread-states. (line 117) * Execution of init_command, thread state: general-thread-states. (line 121) * execution threads (MySQL Cluster): mysql-cluster-programs-ndbmtd. (line 66) * EXISTS, with subqueries: exists-and-not-exists-subqueries. (line 6) * EXIT command (MySQL Cluster): mysql-cluster-mgm-client-commands. (line 176) * exit command, mysql: mysql-commands. (line 131) * EXIT SINGLE USER MODE command (MySQL Cluster): mysql-cluster-mgm-client-commands. (line 166) * exit-info option, mysqld: server-options. (line 726) * EXP(): mathematical-functions. (line 197) * expire_logs_days system variable: server-system-variables. (line 1507) * EXPLAIN <1>: explain. (line 6) * EXPLAIN: using-explain. (line 6) * EXPLAIN PARTITIONS: partitioning-info. (line 6) * EXPLAIN used with partitioned tables: partitioning-info. (line 6) * explicit default values: data-type-defaults. (line 6) * EXPORT_SET(): string-functions. (line 242) * expression aliases <1>: select. (line 106) * expression aliases: group-by-hidden-columns. (line 80) * expression syntax: expressions. (line 6) * expressions, extended: pattern-matching. (line 6) * extend-check option, myisamchk <1>: myisamchk-repair-options. (line 28) * extend-check option, myisamchk: myisamchk-check-options. (line 18) * extended option, mysqlcheck: mysqlcheck. (line 288) * extended-insert option, mysqldump: mysqldump. (line 534) * extensions, to standard SQL: compatibility. (line 15) * ExteriorRing(): polygon-property-functions. (line 21) * external locking <1>: general-thread-states. (line 316) * external locking <2>: external-locking. (line 6) * external locking <3>: myisam-crash-recovery. (line 6) * external locking <4>: server-system-variables. (line 4766) * external locking: server-options. (line 743) * external-locking option, mysqld: server-options. (line 743) * extra-file option, my_print_defaults: my-print-defaults. (line 43) * extra-node-info option, ndb_desc: mysql-cluster-programs-ndb-desc. (line 196) * extra-partition-info option, ndb_desc: mysql-cluster-programs-ndb-desc. (line 181) * EXTRACT(): date-and-time-functions. (line 525) * extracting, dates: date-calculations. (line 6) * ExtractValue(): xml-functions. (line 150) * failover, in MySQL Cluster replication: mysql-cluster-replication-failover. (line 6) * failover, Java clients: mysql-cluster-basics. (line 116) * FALSE <1>: boolean-values. (line 6) * FALSE: number-syntax. (line 6) * FALSE, testing for: comparison-operators. (line 130) * fast option, myisamchk: myisamchk-check-options. (line 33) * fast option, mysqlcheck: mysqlcheck. (line 297) * fatal signal 11: compilation-problems. (line 37) * features of MySQL: features. (line 6) * FEDERATED storage engine <1>: federated-storage-engine. (line 13) * FEDERATED storage engine: storage-engines. (line 23) * FETCH: fetch. (line 6) * Fetch, thread command: thread-commands. (line 56) * Field List, thread command: thread-commands. (line 61) * FIELD(): string-functions. (line 260) * field, changing: alter-table. (line 307) * fields option, ndb_config: mysql-cluster-programs-ndb-config. (line 201) * fields-enclosed-by option, mysqldump <1>: mysqlimport. (line 186) * fields-enclosed-by option, mysqldump: mysqldump. (line 542) * fields-escaped-by option, mysqldump <1>: mysqlimport. (line 190) * fields-escaped-by option, mysqldump: mysqldump. (line 546) * fields-optionally-enclosed-by option, mysqldump <1>: mysqlimport. (line 188) * fields-optionally-enclosed-by option, mysqldump: mysqldump. (line 544) * fields-terminated-by option, mysqldump <1>: mysqlimport. (line 184) * fields-terminated-by option, mysqldump: mysqldump. (line 540) * FILE: string-functions. (line 379) * files, binary log: binary-log. (line 13) * files, config.cache: compilation-problems. (line 6) * files, error messages: error-message-language. (line 6) * files, general query log: query-log. (line 6) * FILES, INFORMATION_SCHEMA table: files-table. (line 6) * files, log <1>: log-file-maintenance. (line 6) * files, log: source-configuration-options. (line 6) * files, my.cnf: replication-features. (line 43) * files, not found message: file-permissions. (line 6) * files, permissions: file-permissions. (line 6) * files, repairing: myisamchk-repair-options. (line 6) * files, script: batch-mode. (line 6) * files, size limits: table-size-limit. (line 6) * files, slow query log: slow-query-log. (line 6) * files, text <1>: mysqlimport. (line 6) * files, text: batch-commands. (line 6) * files, tmp: mysql-install-db-problems. (line 70) * filesort optimization: order-by-optimization. (line 113) * FileSystemPath: mysql-cluster-ndbd-definition. (line 303) * FileSystemPathDataFiles: mysql-cluster-ndbd-definition. (line 3519) * FileSystemPathDD: mysql-cluster-ndbd-definition. (line 3481) * FileSystemPathUndoFiles: mysql-cluster-ndbd-definition. (line 3552) * FIND_IN_SET(): string-functions. (line 279) * Finished reading one binlog; switching to next binlog, thread state: master-thread-states. (line 17) * firewalls (software), and MySQL Cluster: mysql-cluster-security-networking-issues. (line 98) * first-slave option, mysqldump: mysqldump. (line 552) * fix-db-names option, mysqlcheck: mysqlcheck. (line 301) * fix-table-names option, mysqlcheck: mysqlcheck. (line 307) * FIXED data type: numeric-type-overview. (line 246) * fixed-point arithmetic: precision-math. (line 14) * FLOAT data type: numeric-type-overview. (line 170) * floating-point number: numeric-type-overview. (line 215) * floating-point values, and replication: replication-features-floatvalues. (line 6) * floats: number-syntax. (line 6) * FLOOR(): mathematical-functions. (line 210) * FLUSH: flush. (line 6) * flush option, mysqld: server-options. (line 768) * flush system variable: server-system-variables. (line 1534) * flush tables: mysqladmin. (line 186) * FLUSH, and replication: replication-features-flush. (line 6) * flush-logs option, mysqldump: mysqldump. (line 557) * flush-privileges option, mysqldump: mysqldump. (line 569) * flush_time system variable: server-system-variables. (line 1556) * Flushing tables, thread state: general-thread-states. (line 132) * flushlog option, mysqlhotcopy: mysqlhotcopy. (line 112) * FOR UPDATE: select. (line 457) * FORCE INDEX <1>: optimizer-issues. (line 27) * FORCE INDEX: index-hints. (line 6) * FORCE KEY: index-hints. (line 6) * force option, myisamchk <1>: myisamchk-repair-options. (line 37) * force option, myisamchk: myisamchk-check-options. (line 37) * force option, myisampack: myisampack. (line 66) * force option, mysql: mysql-command-options. (line 275) * force option, mysql_convert_table_format: mysql-convert-table-format. (line 28) * force option, mysql_install_db: mysql-install-db. (line 55) * force option, mysql_upgrade: mysql-upgrade. (line 140) * force option, mysqladmin: mysqladmin. (line 349) * force option, mysqlcheck: mysqlcheck. (line 313) * force option, mysqldump: mysqldump. (line 577) * force option, mysqlimport: mysqlimport. (line 195) * force-read option, mysqlbinlog: mysqlbinlog. (line 357) * foreign key, constraint: constraint-primary-key. (line 6) * foreign key, deleting <1>: innodb-foreign-key-constraints. (line 162) * foreign key, deleting: alter-table. (line 428) * foreign keys <1>: alter-table. (line 405) * foreign keys <2>: example-foreign-keys. (line 6) * foreign keys: ansi-diff-foreign-keys. (line 6) * foreign_key_checks session variable: server-system-variables. (line 1585) * FORMAT(): string-functions. (line 294) * Forums: forums. (line 6) * FOUND_ROWS(): information-functions. (line 212) * FragmentLogFileSize: mysql-cluster-ndbd-definition. (line 1083) * FreeBSD troubleshooting: compilation-problems. (line 133) * freeing items, thread state: general-thread-states. (line 126) * frequently-asked questions about DRBD <1>: faqs-drbd. (line 6) * frequently-asked questions about DRBD: faqs-mysql-drbd-heartbeat. (line 19) * frequently-asked questions about MySQL Cluster: faqs-mysql-cluster. (line 6) * FROM: select. (line 134) * FROM_DAYS(): date-and-time-functions. (line 541) * FROM_UNIXTIME(): date-and-time-functions. (line 552) * ft_boolean_syntax system variable: server-system-variables. (line 1606) * ft_max_word_len myisamchk variable: myisamchk-general-options. (line 53) * ft_max_word_len system variable: server-system-variables. (line 1643) * ft_min_word_len myisamchk variable: myisamchk-general-options. (line 53) * ft_min_word_len system variable: server-system-variables. (line 1668) * ft_query_expansion_limit system variable: server-system-variables. (line 1694) * ft_stopword_file myisamchk variable: myisamchk-general-options. (line 53) * ft_stopword_file system variable: server-system-variables. (line 1715) * full disk: full-disk. (line 6) * full-text parser plugins: full-text-plugins. (line 6) * full-text search: fulltext-search. (line 16) * FULLTEXT: fulltext-search. (line 16) * FULLTEXT initialization, thread state: general-thread-states. (line 137) * fulltext join type, optimizer: explain-output. (line 155) * fulltext, stopword list: fulltext-fine-tuning. (line 40) * function names, parsing: function-resolution. (line 6) * function names, resolving ambiguity: function-resolution. (line 6) * function, creating: create-function-udf. (line 6) * function, deleting: drop-function-udf. (line 6) * functions: functions. (line 27) * functions for SELECT and WHERE clauses: functions. (line 27) * functions, and replication: replication-features-functions. (line 6) * functions, arithmetic: bit-functions. (line 6) * functions, bit: bit-functions. (line 6) * functions, C API: c-api-function-overview. (line 6) * functions, C prepared statement API <1>: c-api-prepared-statement-function-overview. (line 6) * functions, C prepared statement API: c-api-prepared-statement-type-conversions. (line 6) * functions, cast: cast-functions. (line 6) * functions, control flow: control-flow-functions. (line 6) * functions, date and time: date-and-time-functions. (line 6) * functions, encryption: encryption-functions. (line 6) * functions, GROUP BY: group-by-functions. (line 6) * functions, grouping: operator-precedence. (line 48) * functions, information: information-functions. (line 6) * functions, mathematical: mathematical-functions. (line 54) * functions, miscellaneous: miscellaneous-functions. (line 6) * functions, native, adding: adding-native-function. (line 6) * functions, new: adding-functions. (line 12) * functions, stored: stored-routines. (line 13) * functions, string: string-functions. (line 11) * functions, string comparison: string-comparison-functions. (line 6) * functions, user-defined: adding-functions. (line 12) * Functions, user-defined <1>: drop-function-udf. (line 6) * Functions, user-defined: create-function-udf. (line 6) * functions, user-defined, adding: adding-udf. (line 15) * gap event: mysql-cluster-replication-issues. (line 36) * gap lock, InnoDB <1>: innodb-next-key-locking. (line 6) * gap lock, InnoDB <2>: innodb-record-level-locks. (line 6) * gap lock, InnoDB <3>: innodb-transaction-model. (line 65) * gap lock, InnoDB: innodb-parameters. (line 1067) * gb2312, gbk: faqs-cjk. (line 6) * gcc: source-configuration-options. (line 397) * gci option, ndb_select_all: mysql-cluster-programs-ndb-select-all. (line 66) * GCP Stop errors (MySQL Cluster): mysql-cluster-ndbd-definition. (line 3731) * gdb option, mysqld: server-options. (line 788) * gdb, using: using-gdb-on-mysqld. (line 6) * general information: introduction. (line 18) * General Public License: what-is-mysql. (line 39) * general query log: query-log. (line 6) * general-log option, mysqld: server-options. (line 805) * general_log system variable: server-system-variables. (line 1747) * general_log_file system variable: server-system-variables. (line 1773) * geographic feature: gis-introduction. (line 27) * GeomCollFromText(): gis-wkt-functions. (line 14) * GeomCollFromWKB(): gis-wkb-functions. (line 17) * geometry: gis-introduction. (line 40) * GEOMETRY data type: mysql-spatial-datatypes. (line 6) * GEOMETRYCOLLECTION data type: mysql-spatial-datatypes. (line 6) * GeometryCollection(): gis-mysql-specific-functions. (line 31) * GeometryCollectionFromText(): gis-wkt-functions. (line 14) * GeometryCollectionFromWKB(): gis-wkb-functions. (line 17) * GeometryFromText(): gis-wkt-functions. (line 20) * GeometryFromWKB(): gis-wkb-functions. (line 23) * GeometryN(): geometrycollection-property-functions. (line 8) * GeometryType(): general-geometry-property-functions. (line 38) * GeomFromText() <1>: functions-to-convert-geometries-between-formats. (line 29) * GeomFromText(): gis-wkt-functions. (line 20) * GeomFromWKB() <1>: functions-to-convert-geometries-between-formats. (line 36) * GeomFromWKB(): gis-wkb-functions. (line 23) * geospatial feature: gis-introduction. (line 37) * GET_FORMAT(): date-and-time-functions. (line 580) * GET_LOCK(): miscellaneous-functions. (line 42) * getting MySQL: getting-mysql. (line 6) * GIS <1>: gis-introduction. (line 6) * GIS: spatial-extensions. (line 16) * GLength() <1>: multilinestring-property-functions. (line 8) * GLength(): linestring-property-functions. (line 23) * global privileges <1>: revoke. (line 6) * global privileges: grant. (line 6) * GLOBAL_STATUS, INFORMATION_SCHEMA table: status-table. (line 6) * GLOBAL_VARIABLES, INFORMATION_SCHEMA table: variables-table. (line 6) * globalization: globalization. (line 16) * go command, mysql: mysql-commands. (line 135) * goals of MySQL: what-is-mysql. (line 84) * got handler lock, thread state: delayed-insert-thread-states. (line 26) * got old table, thread state: delayed-insert-thread-states. (line 32) * GRANT: grant. (line 6) * GRANT statement: adding-users. (line 6) * grant table distribution (MySQL Cluster): mysql-cluster-privilege-distribution. (line 6) * grant tables, re-creating: mysql-install-db-problems. (line 104) * grant tables, sorting <1>: request-access. (line 51) * grant tables, sorting: connection-access. (line 120) * grant tables, structure: grant-table-structure. (line 6) * grant tables, upgrading: mysql-fix-privilege-tables. (line 6) * granting, privileges: grant. (line 6) * GRANTS: show-grants. (line 6) * greater than (>): comparison-operators. (line 123) * greater than or equal (>=): comparison-operators. (line 116) * greatest timestamp wins (conflict resolution): mysql-cluster-replication-conflict-resolution. (line 255) * greatest timestamp, delete wins (conflict resolution): mysql-cluster-replication-conflict-resolution. (line 285) * GREATEST(): comparison-operators. (line 237) * GROUP BY: group-by-optimization. (line 11) * GROUP BY functions: group-by-functions. (line 6) * GROUP BY, aliases in: group-by-hidden-columns. (line 80) * GROUP BY, extensions to standard SQL <1>: select. (line 204) * GROUP BY, extensions to standard SQL: group-by-hidden-columns. (line 6) * GROUP_CONCAT(): group-by-functions. (line 136) * group_concat_max_len system variable: server-system-variables. (line 1797) * grouping, expressions: operator-precedence. (line 48) * HANDLER: handler. (line 6) * Handlers: declare-handler. (line 6) * handling, errors: udf-return-values. (line 6) * Has read all relay log; waiting for the slave I/O thread to update it, thread state: slave-sql-thread-states. (line 18) * Has sent all binlog to slave; waiting for binlog to be updated, thread state: master-thread-states. (line 22) * hash partitioning: partitioning-hash. (line 10) * hash partitions, managing: partitioning-management-hash-key. (line 6) * hash partitions, splitting and merging: partitioning-management-hash-key. (line 6) * have_archive system variable: server-system-variables. (line 1827) * have_blackhole_engine system variable: server-system-variables. (line 1832) * have_community_features system variable: server-system-variables. (line 1843) * have_compress system variable: server-system-variables. (line 1837) * have_crypt system variable: server-system-variables. (line 1850) * have_csv system variable: server-system-variables. (line 1855) * have_dynamic_loading system variable: server-system-variables. (line 1863) * have_example_engine system variable: server-system-variables. (line 1868) * have_federated_engine system variable: server-system-variables. (line 1873) * have_geometry system variable: server-system-variables. (line 1878) * have_innodb system variable: server-system-variables. (line 1882) * have_isam system variable: server-system-variables. (line 1890) * have_merge_engine system variable: server-system-variables. (line 1896) * have_openssl system variable: server-system-variables. (line 1902) * have_partitioning system variable: server-system-variables. (line 1907) * have_query_cache system variable: server-system-variables. (line 1916) * have_raid system variable: server-system-variables. (line 1939) * have_row_based_replication system variable: server-system-variables. (line 1921) * have_rtree_keys system variable: server-system-variables. (line 1945) * have_ssl system variable: server-system-variables. (line 1950) * have_symlink system variable: server-system-variables. (line 1960) * HAVING: select. (line 218) * header option, ndb_select_all: mysql-cluster-programs-ndb-select-all. (line 39) * header_file option, comp_err: comp-err. (line 44) * HEAP storage engine <1>: memory-storage-engine. (line 6) * HEAP storage engine: storage-engines. (line 23) * HeartbeatIntervalDbApi: mysql-cluster-ndbd-definition. (line 1942) * HeartbeatIntervalDbDb: mysql-cluster-ndbd-definition. (line 1913) * HeartbeatOrder: mysql-cluster-ndbd-definition. (line 1970) * HeartbeatThreadPriority <1>: mysql-cluster-api-definition. (line 213) * HeartbeatThreadPriority: mysql-cluster-mgm-definition. (line 258) * HELP command (MySQL Cluster): mysql-cluster-mgm-client-commands. (line 20) * help command, mysql: mysql-commands. (line 51) * help option, comp_err: comp-err. (line 26) * help option, my_print_defaults: my-print-defaults. (line 25) * help option, myisam_ftdump: myisam-ftdump. (line 58) * HELP option, myisamchk: myisamchk-general-options. (line 16) * help option, myisamchk: myisamchk-general-options. (line 11) * help option, myisampack: myisampack. (line 47) * help option, mysql: mysql-command-options. (line 153) * help option, mysql_convert_table_format: mysql-convert-table-format. (line 24) * help option, mysql_find_rows: mysql-find-rows. (line 31) * help option, mysql_setpermission: mysql-setpermission. (line 29) * help option, mysql_upgrade: mysql-upgrade. (line 116) * help option, mysql_waitpid: mysql-waitpid. (line 27) * help option, mysqlaccess: mysqlaccess. (line 67) * help option, mysqladmin: mysqladmin. (line 298) * help option, mysqlbinlog: mysqlbinlog. (line 174) * help option, mysqlcheck: mysqlcheck. (line 197) * help option, mysqld: server-options. (line 72) * help option, mysqld_multi: mysqld-multi. (line 96) * help option, mysqld_safe: mysqld-safe. (line 119) * help option, mysqldump: mysqldump. (line 327) * help option, mysqldumpslow: mysqldumpslow. (line 45) * help option, mysqlhotcopy: mysqlhotcopy. (line 79) * help option, mysqlimport: mysqlimport. (line 129) * help option, mysqlmanager: instance-manager-command-options. (line 23) * help option, mysqlshow: mysqlshow. (line 110) * help option, mysqlslap: mysqlslap. (line 211) * help option, perror: perror. (line 40) * help option, resolve_stack_dump: resolve-stack-dump. (line 21) * help option, resolveip: resolveip. (line 15) * HELP statement: help. (line 6) * HEX() <1>: mathematical-functions. (line 229) * HEX(): string-functions. (line 307) * hex-blob option, mysqldump: mysqldump. (line 595) * hexadecimal values: hexadecimal-values. (line 6) * hexdump option, mysqlbinlog: mysqlbinlog. (line 364) * HIGH_NOT_PRECEDENCE SQL mode: server-sql-mode. (line 127) * HIGH_PRIORITY: select. (line 476) * hints: extensions-to-ansi. (line 6) * hints, index <1>: index-hints. (line 6) * hints, index: select. (line 142) * history of MySQL: history. (line 6) * HOME environment variable <1>: mysql-history-file. (line 6) * HOME environment variable: environment-variables. (line 18) * host name caching: dns. (line 6) * host name resolution: dns. (line 6) * host name, default: connecting. (line 6) * host option: connecting. (line 129) * host option, mysql: mysql-command-options. (line 279) * host option, mysql_convert_table_format: mysql-convert-table-format. (line 32) * host option, mysql_setpermission: mysql-setpermission. (line 33) * host option, mysqlaccess: mysqlaccess. (line 94) * host option, mysqladmin: mysqladmin. (line 354) * host option, mysqlbinlog: mysqlbinlog. (line 370) * host option, mysqlcheck: mysqlcheck. (line 317) * host option, mysqldump: mysqldump. (line 590) * host option, mysqlhotcopy: mysqlhotcopy. (line 116) * host option, mysqlimport: mysqlimport. (line 201) * host option, mysqlshow: mysqlshow. (line 160) * host option, mysqlslap: mysqlslap. (line 343) * host option, ndb_config: mysql-cluster-programs-ndb-config. (line 128) * host table: request-access. (line 148) * host table, sorting: request-access. (line 51) * Host*SciId* parameters: mysql-cluster-sci-definition. (line 52) * host.frm, problems finding: unix-postinstallation. (line 216) * HostName <1>: mysql-cluster-api-definition. (line 106) * HostName <2>: mysql-cluster-ndbd-definition. (line 123) * HostName: mysql-cluster-mgm-definition. (line 111) * HostName (MySQL Cluster): mysql-cluster-security-networking-issues. (line 40) * hostname system variable: server-system-variables. (line 1967) * HostName1 <1>: mysql-cluster-sci-definition. (line 110) * HostName1 <2>: mysql-cluster-shm-definition. (line 51) * HostName1: mysql-cluster-tcp-definition. (line 65) * HostName2 <1>: mysql-cluster-sci-definition. (line 121) * HostName2 <2>: mysql-cluster-shm-definition. (line 62) * HostName2: mysql-cluster-tcp-definition. (line 76) * HOUR(): date-and-time-functions. (line 617) * howto option, mysqlaccess: mysqlaccess. (line 98) * html option, mysql: mysql-command-options. (line 283) * i-am-a-dummy option, mysql: mysql-command-options. (line 467) * i5/OS: i5os-installation. (line 6) * IBM i5/OS: i5os-installation. (line 6) * IBMDB2I storage engine: storage-engines. (line 23) * icc, and MySQL Cluster support>: porting. (line 32) * icc, MySQL builds: compiler-characteristics. (line 6) * Id <1>: mysql-cluster-api-definition. (line 26) * Id <2>: mysql-cluster-ndbd-definition. (line 61) * Id: mysql-cluster-mgm-definition. (line 16) * id option, ndb_config: mysql-cluster-programs-ndb-config. (line 157) * ID, unique: getting-unique-id. (line 6) * identifiers: identifiers. (line 13) * identifiers, case sensitivity: identifier-case-sensitivity. (line 6) * identifiers, quoting: identifiers. (line 20) * identity session variable: server-system-variables. (line 1982) * IF: if-statement. (line 6) * IF(): control-flow-functions. (line 49) * IFNULL(): control-flow-functions. (line 85) * IGNORE INDEX: index-hints. (line 6) * IGNORE KEY: index-hints. (line 6) * ignore option, mysqlimport: mysqlimport. (line 206) * IGNORE, with partitioned tables: insert. (line 263) * ignore-builtin-innodb option, mysqld: innodb-parameters. (line 134) * ignore-lines option, mysqlimport: mysqlimport. (line 210) * ignore-spaces option, mysql: mysql-command-options. (line 287) * ignore-table option, mysqldump: mysqldump. (line 602) * IGNORE_SPACE SQL mode: server-sql-mode. (line 142) * implicit default values: data-type-defaults. (line 6) * IMPORT TABLESPACE <1>: innodb-multiple-tablespaces. (line 59) * IMPORT TABLESPACE: alter-table. (line 439) * importing, data <1>: mysqlimport. (line 6) * importing, data: batch-commands. (line 6) * IN <1>: any-in-some-subqueries. (line 6) * IN: comparison-operators. (line 252) * in_file option, comp_err: comp-err. (line 48) * include option, mysql_config: mysql-config. (line 20) * increasing with replication, speed: replication. (line 13) * increasing, performance: replication-faq. (line 24) * incremental recovery: point-in-time-recovery. (line 11) * incremental recovery, using MySQL Cluster replication: mysql-cluster-replication-pitr. (line 6) * INDEX DIRECTORY, and replication: replication-features-directory. (line 6) * index hints <1>: index-hints. (line 6) * index hints: select. (line 142) * index join type, optimizer: explain-output. (line 222) * index, deleting <1>: drop-index. (line 6) * index, deleting: alter-table. (line 314) * index, rebuilding: rebuilding-tables. (line 6) * index-record lock, InnoDB <1>: innodb-next-key-locking. (line 6) * index-record lock, InnoDB <2>: innodb-record-level-locks. (line 6) * index-record lock, InnoDB <3>: innodb-transaction-model. (line 65) * index-record lock, InnoDB: innodb-parameters. (line 1067) * index_merge join type, optimizer: explain-output. (line 172) * index_subquery join type, optimizer: explain-output. (line 190) * indexes: create-index. (line 6) * indexes, and BLOB columns <1>: create-table. (line 494) * indexes, and BLOB columns: column-indexes. (line 15) * indexes, and IS NULL: mysql-indexes. (line 137) * indexes, and LIKE: mysql-indexes. (line 111) * indexes, and NULL values: create-table. (line 473) * indexes, and TEXT columns <1>: create-table. (line 494) * indexes, and TEXT columns: column-indexes. (line 15) * indexes, assigning to key cache: cache-index. (line 6) * indexes, block size: server-system-variables. (line 2162) * indexes, columns: column-indexes. (line 6) * indexes, leftmost prefix of: mysql-indexes. (line 88) * indexes, multi-column: multiple-column-indexes. (line 6) * indexes, multiple-part: create-index. (line 6) * indexes, names: identifiers. (line 13) * indexes, use of: mysql-indexes. (line 6) * IndexMemory <1>: mysql-cluster-config-lcp-params. (line 6) * IndexMemory: mysql-cluster-ndbd-definition. (line 472) * INET_ATON(): miscellaneous-functions. (line 102) * INET_NTOA(): miscellaneous-functions. (line 128) * INFO Events (MySQL Cluster): mysql-cluster-log-events. (line 210) * information functions: information-functions. (line 6) * information option, myisamchk: myisamchk-check-options. (line 43) * INFORMATION_SCHEMA: information-schema. (line 37) * INFORMATION_SCHEMA plugins: information-schema-plugins. (line 6) * INFORMATION_SCHEMA, and security issues: mysql-cluster-security-mysql-privileges. (line 118) * INFORMATION_SCHEMA, collation and searching: charset-collation-information-schema. (line 6) * INFORMATION_SCHEMA.ENGINES table, and MySQL Cluster: mysql-cluster-sql-statements. (line 35) * INFORMATION_SCHEMA.GLOBAL_STATUS table, and MySQL Cluster: mysql-cluster-sql-statements. (line 159) * INFORMATION_SCHEMA.GLOBAL_VARIABLES table, and MySQL Cluster: mysql-cluster-sql-statements. (line 84) * Init DB, thread command: thread-commands. (line 65) * init, thread state: general-thread-states. (line 142) * init-file option, mysqld: server-options. (line 828) * init_connect system variable: server-system-variables. (line 1989) * init_file system variable: server-system-variables. (line 2030) * init_slave system variable: replication-options-slave. (line 1217) * InitFragmentLogFiles: mysql-cluster-ndbd-definition. (line 1109) * Initialized, thread state: event-scheduler-thread-states. (line 15) * InitialLogFileGroup: mysql-cluster-ndbd-definition. (line 3594) * InitialNoOfOpenFiles: mysql-cluster-ndbd-definition. (line 1169) * InitialTablespace: mysql-cluster-ndbd-definition. (line 3667) * INNER JOIN: join. (line 6) * innochecksum <1>: innochecksum. (line 6) * innochecksum: programs-overview. (line 165) * InnoDB: innodb-storage-engine. (line 23) * InnoDB buffer pool: innodb-buffer-pool. (line 6) * innodb option, mysqld: innodb-parameters. (line 172) * InnoDB storage engine <1>: innodb-storage-engine. (line 23) * InnoDB storage engine: storage-engines. (line 23) * InnoDB tables: ansi-diff-transactions. (line 6) * InnoDB, and application feature requirements: mysql-cluster-ndb-innodb-usage. (line 6) * InnoDB, applications supported: mysql-cluster-ndb-innodb-workloads. (line 6) * InnoDB, availability: mysql-cluster-compared. (line 36) * InnoDB, backups: innodb-backup. (line 12) * InnoDB, clustered index: innodb-index-types. (line 6) * InnoDB, compared to MySQL Cluster <1>: mysql-cluster-ndb-innodb-usage. (line 6) * InnoDB, compared to MySQL Cluster <2>: mysql-cluster-ndb-innodb-workloads. (line 6) * InnoDB, compared to MySQL Cluster <3>: mysql-cluster-ndb-innodb-engines. (line 6) * InnoDB, compared to MySQL Cluster: mysql-cluster-compared. (line 12) * InnoDB, gap lock <1>: innodb-next-key-locking. (line 6) * InnoDB, gap lock <2>: innodb-record-level-locks. (line 6) * InnoDB, gap lock <3>: innodb-transaction-model. (line 65) * InnoDB, gap lock: innodb-parameters. (line 1067) * InnoDB, index-record lock <1>: innodb-next-key-locking. (line 6) * InnoDB, index-record lock <2>: innodb-record-level-locks. (line 6) * InnoDB, index-record lock <3>: innodb-transaction-model. (line 65) * InnoDB, index-record lock: innodb-parameters. (line 1067) * InnoDB, Monitors <1>: innodb-troubleshooting-datadict. (line 57) * InnoDB, Monitors <2>: innodb-troubleshooting. (line 26) * InnoDB, Monitors <3>: innodb-monitors. (line 12) * InnoDB, Monitors <4>: innodb-file-space. (line 48) * InnoDB, Monitors: innodb-backup. (line 109) * InnoDB, next-key lock <1>: innodb-next-key-locking. (line 6) * InnoDB, next-key lock <2>: innodb-record-level-locks. (line 6) * InnoDB, next-key lock <3>: innodb-transaction-model. (line 65) * InnoDB, next-key lock: innodb-parameters. (line 1067) * InnoDB, NFS <1>: innodb-restrictions. (line 16) * InnoDB, NFS: innodb-configuration. (line 69) * InnoDB, page size <1>: innodb-restrictions. (line 180) * InnoDB, page size: innodb-physical-structure. (line 6) * InnoDB, record-level locks <1>: innodb-next-key-locking. (line 6) * InnoDB, record-level locks <2>: innodb-record-level-locks. (line 6) * InnoDB, record-level locks <3>: innodb-transaction-model. (line 65) * InnoDB, record-level locks: innodb-parameters. (line 1067) * InnoDB, secondary index: innodb-index-types. (line 6) * InnoDB, semi-consistent read: innodb-parameters. (line 1067) * InnoDB, Solaris 10 x86_64 issues: solaris-installation. (line 11) * InnoDB, transaction isolation levels: innodb-transaction-model. (line 53) * innodb-status-file option, mysqld: innodb-parameters. (line 186) * INSERT <1>: insert. (line 12) * INSERT: insert-speed. (line 6) * INSERT ... SELECT: insert-select. (line 6) * INSERT DELAYED: insert-delayed. (line 6) * INSERT statement, grant privileges: adding-users. (line 116) * INSERT(): string-functions. (line 325) * insert, thread state: delayed-insert-thread-states. (line 76) * insert-ignore option, mysqldump: mysqldump. (line 609) * insert_id session variable: server-system-variables. (line 2062) * insertable views, insertable: view-updatability. (line 6) * inserting, speed of: insert-speed. (line 6) * inserts, concurrent <1>: concurrent-inserts. (line 6) * inserts, concurrent: internal-locking. (line 76) * install option, mysqld: server-options. (line 856) * install option, mysqlmanager: instance-manager-command-options. (line 97) * INSTALL PLUGIN: install-plugin. (line 6) * install-manual option, mysqld: server-options. (line 867) * installation layouts: installation-layouts. (line 6) * installation overview: source-installation. (line 19) * installing MySQL Cluster: mysql-cluster-installation. (line 16) * installing MySQL Cluster, Linux: mysql-cluster-install-linux. (line 12) * installing MySQL Cluster, Linux binary release: mysql-cluster-install-linux-binary. (line 6) * installing MySQL Cluster, Linux RPM: mysql-cluster-install-linux-rpm. (line 6) * installing MySQL Cluster, Linux source release: mysql-cluster-install-linux-source. (line 6) * installing MySQL Cluster, Windows: mysql-cluster-install-windows. (line 13) * installing MySQL Cluster, Windows binary release: mysql-cluster-install-windows-binary. (line 6) * installing MySQL Cluster, Windows source: mysql-cluster-install-windows-source. (line 6) * installing plugins <1>: install-plugin. (line 6) * installing plugins: server-plugin-loading. (line 6) * installing, binary distribution: binary-installation. (line 6) * installing, installing on HP-UX: hpux-installation. (line 11) * installing, installing on IBM-AIX: aix-installation. (line 10) * installing, Linux RPM packages: linux-installation-rpm. (line 6) * installing, Mac OS X PKG packages: macosx-installation. (line 14) * installing, overview: installing. (line 24) * installing, Perl: perl-support. (line 12) * installing, Perl on Windows: activestate-perl. (line 6) * installing, Solaris PKG packages: solaris-installation. (line 11) * installing, source distribution: source-installation. (line 19) * installing, user-defined functions: udf-compiling. (line 6) * INSTR(): string-functions. (line 343) * INT data type: numeric-type-overview. (line 116) * integer arithmetic: precision-math. (line 14) * INTEGER data type: numeric-type-overview. (line 121) * integers: number-syntax. (line 6) * interactive_timeout system variable: server-system-variables. (line 2068) * InteriorRingN(): polygon-property-functions. (line 35) * internal compiler errors: compilation-problems. (line 37) * internal locking: internal-locking. (line 6) * internals: mysql-internals. (line 11) * internationalization: globalization. (line 16) * Internet Relay Chat: irc. (line 6) * Intersection(): spatial-operators. (line 26) * Intersects(): functions-that-test-spatial-relationships-between-geometries. (line 49) * INTERVAL(): comparison-operators. (line 312) * introducer, string literal <1>: charset-literal. (line 11) * introducer, string literal: string-syntax. (line 33) * invalid data, constraint: constraint-invalid-data. (line 6) * invalidating query cache entries, thread state: query-cache-thread-states. (line 19) * IRC: irc. (line 6) * IS boolean_value: comparison-operators. (line 130) * IS NOT boolean_value: comparison-operators. (line 138) * IS NOT NULL: comparison-operators. (line 188) * IS NULL <1>: comparison-operators. (line 146) * IS NULL: is-null-optimization. (line 6) * IS NULL, and indexes: mysql-indexes. (line 137) * IS_FREE_LOCK(): miscellaneous-functions. (line 138) * IS_USED_LOCK(): miscellaneous-functions. (line 149) * isamlog <1>: myisamlog. (line 6) * isamlog: programs-overview. (line 180) * IsClosed(): multilinestring-property-functions. (line 25) * IsEmpty(): general-geometry-property-functions. (line 75) * ISNULL(): comparison-operators. (line 295) * ISOLATION LEVEL: set-transaction. (line 6) * IsRing(): linestring-property-functions. (line 80) * IsSimple(): general-geometry-property-functions. (line 81) * ITERATE: iterate-statement. (line 6) * iterations option, mysqlslap: mysqlslap. (line 347) * Japanese character sets, conversion: faqs-cjk. (line 6) * Japanese, Korean, Chinese character sets, frequently asked questions: faqs-cjk. (line 6) * jdbc:mysql:loadbalance://: mysql-cluster-basics. (line 116) * JOIN: join. (line 6) * join algorithm, Block Nested-Loop: nested-loop-joins. (line 6) * join algorithm, Nested-Loop: nested-loop-joins. (line 6) * join option, myisampack: myisampack. (line 78) * join type, ALL: explain-output. (line 231) * join type, const: explain-output. (line 94) * join type, eq_ref: explain-output. (line 111) * join type, fulltext: explain-output. (line 155) * join type, index: explain-output. (line 222) * join type, index_merge: explain-output. (line 172) * join type, index_subquery: explain-output. (line 190) * join type, range: explain-output. (line 198) * join type, ref: explain-output. (line 132) * join type, ref_or_null: explain-output. (line 159) * join type, system: explain-output. (line 89) * join type, unique_subquery: explain-output. (line 180) * join, nested-loop algorithm: nested-join-optimization. (line 167) * join_buffer_size system variable: server-system-variables. (line 2093) * keep_files_on_create system variable: server-system-variables. (line 2127) * keepold option, mysqlhotcopy: mysqlhotcopy. (line 122) * key cache, assigning indexes to: cache-index. (line 6) * Key cache, MyISAM: myisam-key-cache. (line 15) * key partitioning: partitioning-key. (line 6) * key partitions, managing: partitioning-management-hash-key. (line 6) * key partitions, splitting and merging: partitioning-management-hash-key. (line 6) * key space, MyISAM: key-space. (line 6) * key_buffer_size myisamchk variable: myisamchk-general-options. (line 53) * key_buffer_size system variable: server-system-variables. (line 2162) * key_cache_age_threshold system variable: server-system-variables. (line 2261) * key_cache_block_size system variable: server-system-variables. (line 2292) * key_cache_division_limit system variable: server-system-variables. (line 2313) * KEY_COLUMN_USAGE, INFORMATION_SCHEMA table: key-column-usage-table. (line 6) * keys: column-indexes. (line 6) * keys option, mysqlshow: mysqlshow. (line 164) * keys, foreign <1>: example-foreign-keys. (line 6) * keys, foreign: ansi-diff-foreign-keys. (line 6) * keys, multi-column: multiple-column-indexes. (line 6) * keys, searching on two: searching-on-two-keys. (line 6) * keys-used option, myisamchk: myisamchk-repair-options. (line 42) * keywords: reserved-words. (line 6) * KILL: kill. (line 6) * Kill, thread command: thread-commands. (line 69) * Killed, thread state: general-thread-states. (line 158) * Killing slave, thread state: slave-connection-thread-states. (line 21) * known errors: bugs. (line 6) * Korean: faqs-cjk. (line 6) * Korean, Chinese, Japanese character sets, frequently asked questions: faqs-cjk. (line 6) * language option, mysqld: server-options. (line 879) * language support, error messages: error-message-language. (line 6) * language system variable: server-system-variables. (line 2336) * large page support: large-page-support. (line 6) * large tables, and MySQL Cluster: create-table. (line 814) * large tables, creating in NDB: create-table. (line 814) * large-pages option, mysqld: server-options. (line 906) * large_files_support system variable: server-system-variables. (line 2361) * large_page_size system variable: server-system-variables. (line 2392) * large_pages system variable: server-system-variables. (line 2371) * last row, unique ID: getting-unique-id. (line 6) * LAST_DAY(): date-and-time-functions. (line 629) * last_insert_id session variable: server-system-variables. (line 2409) * LAST_INSERT_ID() <1>: insert. (line 206) * LAST_INSERT_ID(): ansi-diff-transactions. (line 159) * LAST_INSERT_ID() and stored routines: stored-routines-last-insert-id. (line 6) * LAST_INSERT_ID() and triggers: stored-routines-last-insert-id. (line 6) * LAST_INSERT_ID(), and replication: replication-features-auto-increment. (line 6) * LAST_INSERT_ID([expr]): information-functions. (line 296) * layout of installation: installation-layouts. (line 6) * lc_time_names system variable: server-system-variables. (line 2417) * LCASE(): string-functions. (line 357) * LD_LIBRARY_PATH environment variable: perl-support-problems. (line 20) * LD_RUN_PATH environment variable <1>: perl-support-problems. (line 20) * LD_RUN_PATH environment variable <2>: environment-variables. (line 18) * LD_RUN_PATH environment variable: solaris-installation-source. (line 97) * ldata option, mysql_install_db: mysql-install-db. (line 61) * LDML syntax: ldml-rules. (line 6) * LEAST(): comparison-operators. (line 326) * LEAVE: leave-statement. (line 6) * ledir option, mysqld_safe: mysqld-safe. (line 161) * LEFT JOIN <1>: join. (line 6) * LEFT JOIN: left-join-optimization. (line 6) * LEFT OUTER JOIN: join. (line 6) * LEFT(): string-functions. (line 361) * leftmost prefix of indexes: mysql-indexes. (line 88) * legal names: identifiers. (line 13) * length option, myisam_ftdump: myisam-ftdump. (line 70) * LENGTH(): string-functions. (line 369) * less than (<): comparison-operators. (line 109) * less than or equal (<=): comparison-operators. (line 102) * libmysqld: libmysqld. (line 14) * libmysqld, options: libmysqld-options. (line 6) * libmysqld-libs option, mysql_config: mysql-config. (line 24) * library, mysqlclient: connectors-apis. (line 24) * library, mysqld: connectors-apis. (line 24) * libs option, mysql_config: mysql-config. (line 29) * libs_r option, mysql_config: mysql-config. (line 34) * license system variable: server-system-variables. (line 2439) * LIKE: string-comparison-functions. (line 20) * LIKE, and indexes: mysql-indexes. (line 111) * LIKE, and wildcards: mysql-indexes. (line 111) * LIMIT <1>: select. (line 275) * LIMIT <2>: information-functions. (line 212) * LIMIT: limit-optimization. (line 6) * LIMIT, and replication: replication-features-limit. (line 6) * limitations of MySQL Cluster: mysql-cluster-limitations. (line 20) * limitations, design: design-limitations. (line 6) * limitations, MySQL Limitations: limits. (line 14) * limitations, replication: replication-features. (line 43) * limits, file-size: table-size-limit. (line 6) * limits, MySQL Limits, limits in MySQL: limits. (line 14) * line-numbers option, mysql: mysql-command-options. (line 293) * linear hash partitioning: partitioning-linear-hash. (line 6) * linear key partitioning: partitioning-key. (line 109) * linefeed (\n) <1>: load-data. (line 429) * linefeed (\n): string-syntax. (line 60) * LineFromText(): gis-wkt-functions. (line 25) * LineFromWKB(): gis-wkb-functions. (line 28) * lines-terminated-by option, mysqldump <1>: mysqlimport. (line 214) * lines-terminated-by option, mysqldump: mysqldump. (line 614) * LINESTRING data type: mysql-spatial-datatypes. (line 6) * LineString(): gis-mysql-specific-functions. (line 35) * LineStringFromText(): gis-wkt-functions. (line 25) * LineStringFromWKB(): gis-wkb-functions. (line 28) * linking: building-clients. (line 11) * linking, errors: c-api-linking-problems. (line 6) * linking, problems: c-api-linking-problems. (line 6) * linking, speed: compile-and-link-options. (line 6) * links, symbolic: symbolic-links. (line 12) * list partitioning: partitioning-list. (line 6) * list partitions, adding and dropping: partitioning-management-range-list. (line 6) * list partitions, managing: partitioning-management-range-list. (line 6) * list-users option, mysqlmanager: instance-manager-command-options. (line 102) * literals: literals. (line 16) * LN(): mathematical-functions. (line 236) * LOAD DATA FROM MASTER: load-data-from-master. (line 6) * LOAD DATA INFILE <1>: problems-with-null. (line 51) * LOAD DATA INFILE: load-data. (line 6) * LOAD DATA, and replication: replication-features-load-data. (line 6) * load emulation: mysqlslap. (line 6) * LOAD INDEX INTO CACHE, and partitioning: partitioning-limitations. (line 379) * LOAD TABLE FROM MASTER: load-table-from-master. (line 6) * LOAD_FILE(): string-functions. (line 379) * loading, tables: loading-tables. (line 6) * local checkpoints (MySQL Cluster): mysql-cluster-config-lcp-params. (line 6) * local option, mysqlimport: mysqlimport. (line 223) * local-infile option, mysql: mysql-command-options. (line 298) * local-infile option, mysqld: privileges-options. (line 50) * local-load option, mysqlbinlog: mysqlbinlog. (line 374) * local_infile system variable: server-system-variables. (line 2453) * localhost, special treatment of: connecting. (line 75) * localization: globalization. (line 16) * localstatedir option, configure: source-configuration-options. (line 349) * LOCALTIME: date-and-time-functions. (line 644) * LOCALTIMESTAMP: date-and-time-functions. (line 648) * LOCATE(): string-functions. (line 400) * LOCK IN SHARE MODE: select. (line 457) * Lock Monitor, InnoDB: innodb-monitors. (line 12) * lock option, ndb_select_all: mysql-cluster-programs-ndb-select-all. (line 15) * LOCK TABLES: lock-tables. (line 12) * lock-all-tables option, mysqldump: mysqldump. (line 620) * lock-directory option, mysqlslap: mysqlslap. (line 351) * lock-tables option, mysqldump: mysqldump. (line 627) * lock-tables option, mysqlimport: mysqlimport. (line 227) * Locked, thread state: general-thread-states. (line 167) * locked_in_memory system variable: server-system-variables. (line 2467) * LockExecuteThreadToCPU: mysql-cluster-ndbd-definition. (line 3157) * locking: system-optimization. (line 24) * locking methods: internal-locking. (line 6) * locking, external <1>: general-thread-states. (line 316) * locking, external <2>: external-locking. (line 6) * locking, external <3>: myisam-crash-recovery. (line 6) * locking, external <4>: server-system-variables. (line 4766) * locking, external: server-options. (line 743) * locking, internal: internal-locking. (line 6) * locking, row-level <1>: internal-locking. (line 6) * locking, row-level: ansi-diff-transactions. (line 167) * locking, table-level: internal-locking. (line 6) * LockMaintThreadsToCPU: mysql-cluster-ndbd-definition. (line 3195) * LockPagesInMainMemory: mysql-cluster-ndbd-definition. (line 1539) * log files: source-configuration-options. (line 6) * log files (MySQL Cluster): mysql-cluster-programs-ndbd. (line 349) * log files (MySQL Cluster), ndbmtd: mysql-cluster-programs-ndbmtd. (line 134) * log files, maintaining: log-file-maintenance. (line 6) * log option, mysqld: server-options. (line 937) * log option, mysqld_multi: mysqld-multi. (line 118) * log option, mysqlmanager: instance-manager-command-options. (line 107) * log system variable: server-system-variables. (line 2477) * LOG(): mathematical-functions. (line 250) * log, changes: news. (line 18) * log-bin option, mysqld: replication-options-binary-log. (line 48) * log-bin-index option, mysqld: replication-options-binary-log. (line 78) * log-bin-trust-function-creators option, mysqld: replication-options-binary-log. (line 95) * log-error option, mysqld: server-options. (line 973) * log-error option, mysqld_safe: mysqld-safe. (line 167) * log-error option, mysqldump: mysqldump. (line 641) * log-isam option, mysqld: server-options. (line 995) * log-long-format option, mysqld: server-options. (line 1010) * log-output option, mysqld: server-options. (line 1028) * log-queries-not-using-indexes option, mysqld: server-options. (line 1072) * log-short-format option, mysqld: server-options. (line 1095) * log-slave-updates option, mysqld: replication-options-slave. (line 176) * log-slow-admin-statements option, mysqld: server-options. (line 1111) * log-slow-queries option, mysqld: server-options. (line 1127) * log-slow-slave-statements option, mysqld: replication-options-slave. (line 227) * log-tc option, mysqld: server-options. (line 1164) * log-tc-size option, mysqld: server-options. (line 1183) * log-warnings option, mysqld <1>: replication-options-slave. (line 246) * log-warnings option, mysqld: server-options. (line 1207) * LOG10(): mathematical-functions. (line 290) * LOG2(): mathematical-functions. (line 277) * log_bin system variable: server-system-variables. (line 2485) * log_bin_trust_function_creators system variable: server-system-variables. (line 2500) * log_error system variable: server-system-variables. (line 2530) * log_output system variable: server-system-variables. (line 2549) * log_queries_not_using_indexes system variable: server-system-variables. (line 2581) * log_slave_updates system variable: server-system-variables. (line 2601) * log_slow_queries system variable: server-system-variables. (line 2608) * log_warnings system variable: server-system-variables. (line 2635) * logbuffers, ndbinfo table: mysql-cluster-ndbinfo-logbuffers. (line 6) * LogDestination: mysql-cluster-mgm-definition. (line 127) * logging commands (MySQL Cluster): mysql-cluster-logging-management-commands. (line 6) * logging slow query, thread state: general-thread-states. (line 171) * logical operators: logical-operators. (line 6) * login, thread state: general-thread-states. (line 180) * LogLevelCheckpoint: mysql-cluster-ndbd-definition. (line 2803) * LogLevelCongestion: mysql-cluster-ndbd-definition. (line 2868) * LogLevelConnection: mysql-cluster-ndbd-definition. (line 2835) * LogLevelError: mysql-cluster-ndbd-definition. (line 2851) * LogLevelInfo: mysql-cluster-ndbd-definition. (line 2885) * LogLevelNodeRestart: mysql-cluster-ndbd-definition. (line 2820) * LogLevelShutdown: mysql-cluster-ndbd-definition. (line 2770) * LogLevelStartup: mysql-cluster-ndbd-definition. (line 2754) * LogLevelStatistic: mysql-cluster-ndbd-definition. (line 2786) * logs, and TIMESTAMP: upgrading-from-previous-series. (line 737) * logs, flushing: server-logs. (line 30) * logs, server: server-logs. (line 15) * logspaces, ndbinfo table: mysql-cluster-ndbinfo-logspaces. (line 6) * LONG data type: blob. (line 6) * Long Data, thread command: thread-commands. (line 73) * long_query_time system variable: server-system-variables. (line 2665) * LONGBLOB data type: string-type-overview. (line 218) * LongMessageBuffer: mysql-cluster-ndbd-definition. (line 938) * LONGTEXT data type: string-type-overview. (line 228) * LOOP: loop-statement. (line 6) * loops option, ndb_show_tables: mysql-cluster-programs-ndb-show-tables. (line 39) * lost connection errors: error-lost-connection. (line 6) * low-priority option, mysqlimport: mysqlimport. (line 232) * low-priority-updates option, mysqld: server-options. (line 1248) * low_priority_updates system variable: server-system-variables. (line 2698) * LOWER(): string-functions. (line 417) * lower_case_file_system system variable: server-system-variables. (line 2724) * lower_case_table_names system variable: server-system-variables. (line 2746) * LPAD(): string-functions. (line 441) * LTRIM(): string-functions. (line 452) * Mac OS X: connector-odbc. (line 17) * Mac OS X, installation: macosx-installation. (line 14) * mailing list address: introduction. (line 82) * mailing lists: mailing-lists. (line 10) * mailing lists, archive location: mailing-lists. (line 10) * mailing lists, guidelines: mailing-list-use. (line 6) * main features of MySQL: features. (line 6) * maintaining, log files: log-file-maintenance. (line 6) * maintaining, tables: myisam-maintenance-schedule. (line 6) * maintenance, tables: mysqlcheck. (line 6) * make_binary_distribution: programs-overview. (line 74) * MAKE_SET(): string-functions. (line 461) * make_win_bin_dist <1>: make-win-bin-dist. (line 6) * make_win_bin_dist: programs-overview. (line 80) * make_win_bin_dist, debug option: make-win-bin-dist. (line 36) * make_win_bin_dist, embedded option: make-win-bin-dist. (line 41) * make_win_bin_dist, exe-suffix option: make-win-bin-dist. (line 46) * make_win_bin_dist, no-debug option: make-win-bin-dist. (line 52) * make_win_bin_dist, no-embedded option: make-win-bin-dist. (line 56) * make_win_bin_dist, only-debug option: make-win-bin-dist. (line 60) * MAKEDATE(): date-and-time-functions. (line 652) * MAKETIME(): date-and-time-functions. (line 664) * Making temp file, thread state: slave-sql-thread-states. (line 25) * malicious SQL statements, and MySQL Cluster: mysql-cluster-security-mysql-privileges. (line 86) * manage keys, thread state: general-thread-states. (line 185) * management client (MySQL Cluster): mysql-cluster-programs-ndb-mgm. (line 6) * management node (MySQL Cluster), defined: mysql-cluster-basics. (line 6) * management nodes (MySQL Cluster): mysql-cluster-programs-ndb-mgmd. (line 6) * managing MySQL Cluster: mysql-cluster-management. (line 22) * managing MySQL Cluster processes: mysql-cluster-programs. (line 32) * manual, available formats: manual-info. (line 31) * manual, online location: manual-info. (line 6) * manual, syntax conventions: manual-conventions. (line 8) * manual, typographical conventions: manual-conventions. (line 8) * master-connect-retry option, mysqld: replication-options-slave. (line 281) * master-data option, mysqldump: mysqldump. (line 646) * master-host option, mysqld: replication-options-slave. (line 307) * master-info-file option, mysqld: replication-options-slave. (line 327) * master-password option, mysqld: replication-options-slave. (line 345) * master-port option, mysqld: replication-options-slave. (line 366) * master-retry-count option, mysqld: replication-options-slave. (line 387) * master-ssl option, mysqld: replication-options-slave. (line 417) * master-ssl-ca option, mysqld: replication-options-slave. (line 417) * master-ssl-capath option, mysqld: replication-options-slave. (line 417) * master-ssl-cert option, mysqld: replication-options-slave. (line 417) * master-ssl-cipher option, mysqld: replication-options-slave. (line 417) * master-ssl-key option, mysqld: replication-options-slave. (line 417) * master-user option, mysqld: replication-options-slave. (line 432) * MASTER_POS_WAIT() <1>: master-pos-wait. (line 6) * MASTER_POS_WAIT(): miscellaneous-functions. (line 159) * MATCH ... AGAINST(): fulltext-search. (line 16) * matching, patterns: pattern-matching. (line 6) * math: precision-math. (line 14) * mathematical functions: mathematical-functions. (line 54) * MAX(): group-by-functions. (line 191) * MAX(DISTINCT): group-by-functions. (line 191) * max-binlog-dump-events option, mysqld: replication-options-binary-log. (line 327) * max-record-length option, myisamchk: myisamchk-repair-options. (line 58) * max-relay-log-size option, mysqld: replication-options-slave. (line 455) * max_allowed_packet system variable: server-system-variables. (line 2794) * max_allowed_packet variable: mysql-command-options. (line 616) * max_allowed_packet, and replication: replication-features-max-allowed-packet. (line 6) * max_binlog_cache_size system variable: replication-options-binary-log. (line 570) * max_binlog_size system variable: replication-options-binary-log. (line 607) * max_connect_errors system variable: server-system-variables. (line 2839) * max_connections system variable: server-system-variables. (line 2874) * MAX_CONNECTIONS_PER_HOUR: user-resources. (line 6) * max_delayed_threads system variable: server-system-variables. (line 2915) * max_error_count system variable: server-system-variables. (line 2945) * max_heap_table_size system variable: server-system-variables. (line 2968) * max_insert_delayed_threads system variable: server-system-variables. (line 3009) * max_join_size system variable: server-system-variables. (line 3023) * max_join_size variable: mysql-command-options. (line 621) * max_length_for_sort_data system variable: server-system-variables. (line 3063) * max_long_data_size system variable: server-system-variables. (line 3085) * max_prepared_stmt_count system variable: server-system-variables. (line 3112) * MAX_QUERIES_PER_HOUR: user-resources. (line 6) * max_relay_log_size system variable: server-system-variables. (line 3143) * MAX_ROWS, and MySQL Cluster: create-table. (line 814) * MAX_ROWS, and NDB: create-table. (line 814) * max_seeks_for_key system variable: server-system-variables. (line 3172) * max_sort_length system variable: server-system-variables. (line 3207) * max_sp_recursion_depth system variable: server-system-variables. (line 3230) * max_tmp_tables system variable: server-system-variables. (line 3259) * MAX_UPDATES_PER_HOUR: user-resources. (line 6) * MAX_USER_CONNECTIONS: user-resources. (line 6) * max_user_connections system variable: server-system-variables. (line 3289) * max_write_lock_count system variable: server-system-variables. (line 3328) * MaxBufferedEpochs: mysql-cluster-ndbd-definition. (line 2231) * MAXDB SQL mode: server-sql-mode. (line 470) * MaxDMLOperationsPerTransaction: mysql-cluster-ndbd-definition. (line 738) * maximum memory used: mysqladmin. (line 201) * maximums, maximum columns per table: column-count-limit. (line 6) * maximums, maximum number of databases: database-count-limit. (line 6) * maximums, maximum number of tables: database-count-limit. (line 6) * maximums, maximum tables per join: joins-limits. (line 6) * maximums, table size: table-size-limit. (line 6) * MaxLCPStartDelay: mysql-cluster-ndbd-definition. (line 1204) * MaxNoOfAttributes: mysql-cluster-ndbd-definition. (line 1257) * MaxNoOfConcurrentIndexOperations: mysql-cluster-ndbd-definition. (line 779) * MaxNoOfConcurrentOperations: mysql-cluster-ndbd-definition. (line 658) * MaxNoOfConcurrentScans: mysql-cluster-ndbd-definition. (line 869) * MaxNoOfConcurrentSubOperations: mysql-cluster-ndbd-definition. (line 1504) * MaxNoOfConcurrentTransactions: mysql-cluster-ndbd-definition. (line 614) * MaxNoOfExecutionThreads, ndbmtd: mysql-cluster-programs-ndbmtd. (line 66) * MaxNoOfFiredTriggers: mysql-cluster-ndbd-definition. (line 805) * MaxNoOfIndexes: mysql-cluster-ndbd-definition. (line 1424) * MaxNoOfLocalOperations: mysql-cluster-ndbd-definition. (line 720) * MaxNoOfLocalScans: mysql-cluster-ndbd-definition. (line 902) * MaxNoOfOpenFiles: mysql-cluster-ndbd-definition. (line 1142) * MaxNoOfOrderedIndexes: mysql-cluster-ndbd-definition. (line 1349) * MaxNoOfSavedMessages: mysql-cluster-ndbd-definition. (line 1187) * MaxNoOfSubscribers: mysql-cluster-ndbd-definition. (line 1465) * MaxNoOfSubscriptions: mysql-cluster-ndbd-definition. (line 1436) * MaxNoOfTables: mysql-cluster-ndbd-definition. (line 1310) * MaxNoOfTriggers: mysql-cluster-ndbd-definition. (line 1400) * MaxNoOfUniqueHashIndexes: mysql-cluster-ndbd-definition. (line 1375) * MaxParallelScansPerFragment: mysql-cluster-ndbd-definition. (line 972) * MaxScanBatchSize: mysql-cluster-api-definition. (line 231) * MaxStartFailRetries: mysql-cluster-ndbd-definition. (line 3957) * MBR: relations-on-geometry-mbr. (line 6) * MBRContains(): relations-on-geometry-mbr. (line 10) * MBRDisjoint(): relations-on-geometry-mbr. (line 25) * MBREqual(): relations-on-geometry-mbr. (line 30) * MBRIntersects(): relations-on-geometry-mbr. (line 35) * MBROverlaps(): relations-on-geometry-mbr. (line 40) * MBRTouches(): relations-on-geometry-mbr. (line 48) * MBRWithin(): relations-on-geometry-mbr. (line 56) * MD5(): encryption-functions. (line 272) * medium-check option, myisamchk: myisamchk-check-options. (line 47) * medium-check option, mysqlcheck: mysqlcheck. (line 321) * MEDIUMBLOB data type: string-type-overview. (line 203) * MEDIUMINT data type: numeric-type-overview. (line 111) * MEDIUMTEXT data type: string-type-overview. (line 210) * memlock option, mysqld: server-options. (line 1306) * MEMORY storage engine <1>: memory-storage-engine. (line 6) * MEMORY storage engine: storage-engines. (line 23) * MEMORY storage engine, and replication: replication-features-memory. (line 6) * memory usage, myisamchk: myisamchk-memory. (line 6) * memory use <1>: memory-use. (line 6) * memory use: mysqladmin. (line 195) * memory use, in MySQL Cluster: mysql-cluster-limitations-limits. (line 9) * memoryusage, ndbinfo table: mysql-cluster-ndbinfo-memoryusage. (line 6) * MemReportFrequency: mysql-cluster-ndbd-definition. (line 2901) * MERGE storage engine <1>: merge-storage-engine. (line 11) * MERGE storage engine: storage-engines. (line 23) * MERGE tables, defined: merge-storage-engine. (line 11) * metadata, database: information-schema. (line 37) * metadata, stored routines: stored-routines-metadata. (line 6) * metadata, triggers: trigger-metadata. (line 6) * metadata, views: view-metadata. (line 6) * method option, mysqlhotcopy: mysqlhotcopy. (line 126) * methods, locking: internal-locking. (line 6) * mgmd (MySQL Cluster), defined: mysql-cluster-basics. (line 6) * MICROSECOND(): date-and-time-functions. (line 672) * Microsoft Access: connector-odbc-usagenotes-apptips-microsoft-access. (line 6) * Microsoft ADO: connector-odbc-usagenotes-apptips-microsoft-ado. (line 6) * Microsoft Excel: connector-odbc-usagenotes-apptips-microsoft-excel. (line 6) * Microsoft Visual Basic: connector-odbc-usagenotes-apptips-microsoft-visualbasic. (line 6) * Microsoft Visual InterDev: connector-odbc-usagenotes-apptips-microsoft-visualinterdev. (line 6) * MID(): string-functions. (line 478) * MIN(): group-by-functions. (line 211) * MIN(DISTINCT): group-by-functions. (line 211) * min-examined-row-limit option, mysqld: server-options. (line 1275) * min_examined_row_limit system variable: server-system-variables. (line 3357) * Minimum Bounding Rectangle: relations-on-geometry-mbr. (line 6) * minus, unary (-): arithmetic-functions. (line 69) * MINUTE(): date-and-time-functions. (line 682) * mirror sites: getting-mysql. (line 6) * miscellaneous functions: miscellaneous-functions. (line 6) * mixed statements (Replication): replication-features-transactions. (line 38) * MLineFromText(): gis-wkt-functions. (line 30) * MLineFromWKB(): gis-wkb-functions. (line 33) * MOD (modulo): mathematical-functions. (line 303) * MOD(): mathematical-functions. (line 303) * modes, batch: batch-mode. (line 6) * modulo (%): mathematical-functions. (line 303) * modulo (MOD): mathematical-functions. (line 303) * monitor, terminal: tutorial. (line 16) * monitoring-interval option, mysqlmanager: instance-manager-command-options. (line 125) * Monitors, InnoDB <1>: innodb-troubleshooting-datadict. (line 57) * Monitors, InnoDB <2>: innodb-troubleshooting. (line 26) * Monitors, InnoDB <3>: innodb-monitors. (line 12) * Monitors, InnoDB <4>: innodb-file-space. (line 48) * Monitors, InnoDB: innodb-backup. (line 109) * Mono: connector-net. (line 18) * MONTH(): date-and-time-functions. (line 689) * MONTHNAME(): date-and-time-functions. (line 698) * MPointFromText(): gis-wkt-functions. (line 35) * MPointFromWKB(): gis-wkb-functions. (line 38) * MPolyFromText(): gis-wkt-functions. (line 40) * MPolyFromWKB(): gis-wkb-functions. (line 43) * mSQL compatibility: regexp. (line 32) * msql2mysql: msql2mysql. (line 6) * MSSQL SQL mode: server-sql-mode. (line 476) * multi mysqld: mysqld-multi. (line 6) * multi-byte character sets: cannot-initialize-character-set. (line 6) * multi-byte character sets, and MySQL Cluster (replication): mysql-cluster-replication-issues. (line 69) * multi-byte characters: multi-byte-characters. (line 6) * multi-column indexes: multiple-column-indexes. (line 6) * multi-master replication, in MySQL Cluster <1>: mysql-cluster-replication-conflict-resolution. (line 6) * multi-master replication, in MySQL Cluster: mysql-cluster-replication-multi-master. (line 6) * MULTILINESTRING data type: mysql-spatial-datatypes. (line 6) * MultiLineString(): gis-mysql-specific-functions. (line 41) * MultiLineStringFromText(): gis-wkt-functions. (line 30) * MultiLineStringFromWKB(): gis-wkb-functions. (line 33) * multiple servers: multiple-servers. (line 13) * multiple-part index: create-index. (line 6) * multiplication (*): arithmetic-functions. (line 83) * MULTIPOINT data type: mysql-spatial-datatypes. (line 6) * MultiPoint(): gis-mysql-specific-functions. (line 46) * MultiPointFromText(): gis-wkt-functions. (line 35) * MultiPointFromWKB(): gis-wkb-functions. (line 38) * MULTIPOLYGON data type: mysql-spatial-datatypes. (line 6) * MultiPolygon(): gis-mysql-specific-functions. (line 51) * MultiPolygonFromText(): gis-wkt-functions. (line 40) * MultiPolygonFromWKB(): gis-wkb-functions. (line 43) * My, derivation: history. (line 6) * my.cnf file: replication-features. (line 43) * my.cnf, and MySQL Cluster <1>: mysql-cluster-config-example. (line 6) * my.cnf, and MySQL Cluster <2>: mysql-cluster-config-file. (line 22) * my.cnf, and MySQL Cluster: mysql-cluster-install-configuration. (line 6) * my.cnf, in MySQL Cluster: mysql-cluster-programs-mysqld. (line 49) * my_bool C type: c-api-data-structures. (line 63) * my_bool values, printing: c-api-data-structures. (line 63) * my_init(): my-init. (line 6) * my_print_defaults <1>: my-print-defaults. (line 6) * my_print_defaults: programs-overview. (line 267) * my_print_defaults, config-file option: my-print-defaults. (line 29) * my_print_defaults, debug option: my-print-defaults. (line 35) * my_print_defaults, defaults-extra-file option: my-print-defaults. (line 41) * my_print_defaults, defaults-file option: my-print-defaults. (line 31) * my_print_defaults, defaults-group-suffix option: my-print-defaults. (line 48) * my_print_defaults, extra-file option: my-print-defaults. (line 43) * my_print_defaults, help option: my-print-defaults. (line 25) * my_print_defaults, no-defaults option: my-print-defaults. (line 53) * my_print_defaults, verbose option: my-print-defaults. (line 57) * my_print_defaults, version option: my-print-defaults. (line 61) * my_ulonglong C type: c-api-data-structures. (line 49) * my_ulonglong values, printing: c-api-data-structures. (line 49) * MyISAM key cache: myisam-key-cache. (line 15) * MyISAM storage engine <1>: myisam-storage-engine. (line 13) * MyISAM storage engine: storage-engines. (line 23) * MyISAM, compressed tables <1>: compressed-format. (line 6) * MyISAM, compressed tables: myisampack. (line 6) * myisam-block-size option, mysqld: server-options. (line 1350) * myisam-recover option, mysqld <1>: myisam-start. (line 38) * myisam-recover option, mysqld: server-options. (line 1365) * myisam_block_size myisamchk variable: myisamchk-general-options. (line 53) * myisam_data_pointer_size system variable: server-system-variables. (line 3386) * myisam_ftdump <1>: myisam-ftdump. (line 6) * myisam_ftdump: programs-overview. (line 170) * myisam_ftdump, count option: myisam-ftdump. (line 62) * myisam_ftdump, dump option: myisam-ftdump. (line 66) * myisam_ftdump, help option: myisam-ftdump. (line 58) * myisam_ftdump, length option: myisam-ftdump. (line 70) * myisam_ftdump, stats option: myisam-ftdump. (line 74) * myisam_ftdump, verbose option: myisam-ftdump. (line 79) * myisam_max_sort_file_size system variable: server-system-variables. (line 3409) * myisam_mmap_size system variable: server-system-variables. (line 3438) * myisam_recover_options system variable: server-system-variables. (line 3471) * myisam_repair_threads system variable: server-system-variables. (line 3481) * myisam_sort_buffer_size system variable: server-system-variables. (line 3516) * myisam_stats_method system variable: server-system-variables. (line 3553) * myisam_use_mmap system variable: server-system-variables. (line 3590) * myisamchk <1>: myisamchk. (line 15) * myisamchk: programs-overview. (line 175) * myisamchk, analyze option: myisamchk-other-options. (line 9) * myisamchk, backup option: myisamchk-repair-options. (line 10) * myisamchk, block-search option: myisamchk-other-options. (line 18) * myisamchk, character-sets-dir option: myisamchk-repair-options. (line 14) * myisamchk, check option: myisamchk-check-options. (line 9) * myisamchk, check-only-changed option: myisamchk-check-options. (line 14) * myisamchk, correct-checksum option: myisamchk-repair-options. (line 19) * myisamchk, data-file-length option: myisamchk-repair-options. (line 23) * myisamchk, debug option: myisamchk-general-options. (line 21) * myisamchk, description option: myisamchk-other-options. (line 22) * myisamchk, example output: myisamchk-table-info. (line 6) * myisamchk, extend-check option <1>: myisamchk-repair-options. (line 28) * myisamchk, extend-check option: myisamchk-check-options. (line 18) * myisamchk, fast option: myisamchk-check-options. (line 33) * myisamchk, force option <1>: myisamchk-repair-options. (line 37) * myisamchk, force option: myisamchk-check-options. (line 37) * myisamchk, HELP option: myisamchk-general-options. (line 16) * myisamchk, help option: myisamchk-general-options. (line 11) * myisamchk, information option: myisamchk-check-options. (line 43) * myisamchk, keys-used option: myisamchk-repair-options. (line 42) * myisamchk, max-record-length option: myisamchk-repair-options. (line 58) * myisamchk, medium-check option: myisamchk-check-options. (line 47) * myisamchk, no-symlinks option: myisamchk-repair-options. (line 51) * myisamchk, options: myisamchk-general-options. (line 6) * myisamchk, parallel-recover option: myisamchk-repair-options. (line 63) * myisamchk, quick option: myisamchk-repair-options. (line 69) * myisamchk, read-only option: myisamchk-check-options. (line 53) * myisamchk, recover option: myisamchk-repair-options. (line 76) * myisamchk, safe-recover option: myisamchk-repair-options. (line 89) * myisamchk, set-auto-increment[ option: myisamchk-other-options. (line 28) * myisamchk, set-character-set option: myisamchk-repair-options. (line 102) * myisamchk, set-collation option: myisamchk-repair-options. (line 107) * myisamchk, silent option: myisamchk-general-options. (line 27) * myisamchk, sort-index option: myisamchk-other-options. (line 36) * myisamchk, sort-records option: myisamchk-other-options. (line 41) * myisamchk, sort-recover option: myisamchk-repair-options. (line 113) * myisamchk, tmpdir option: myisamchk-repair-options. (line 118) * myisamchk, unpack option: myisamchk-repair-options. (line 128) * myisamchk, update-state option: myisamchk-check-options. (line 60) * myisamchk, verbose option: myisamchk-general-options. (line 32) * myisamchk, version option: myisamchk-general-options. (line 38) * myisamchk, wait option: myisamchk-general-options. (line 42) * myisamlog <1>: myisamlog. (line 6) * myisamlog: programs-overview. (line 180) * myisampack <1>: compressed-format. (line 6) * myisampack <2>: silent-column-changes. (line 70) * myisampack <3>: myisampack. (line 6) * myisampack: programs-overview. (line 185) * myisampack, backup option: myisampack. (line 51) * myisampack, character-sets-dir option: myisampack. (line 56) * myisampack, debug option: myisampack. (line 61) * myisampack, force option: myisampack. (line 66) * myisampack, help option: myisampack. (line 47) * myisampack, join option: myisampack. (line 78) * myisampack, silent option: myisampack. (line 93) * myisampack, test option: myisampack. (line 97) * myisampack, tmpdir option: myisampack. (line 101) * myisampack, verbose option: myisampack. (line 106) * myisampack, version option: myisampack. (line 111) * myisampack, wait option: myisampack. (line 115) * MyODBC: connector-odbc. (line 17) * mysql <1>: mysql. (line 15) * mysql: programs-overview. (line 124) * mysql \. (command for reading from text files) <1>: batch-commands. (line 6) * mysql \. (command for reading from text files): batch-mode. (line 90) * MySQL binary distribution: which-version. (line 18) * MYSQL C type: c-api-data-structures. (line 10) * MySQL Cluster: mysql-cluster. (line 16) * MySQL Cluster Disk Data: mysql-cluster-disk-data. (line 12) * MySQL Cluster Disk Data, creating log file groups: mysql-cluster-disk-data-objects. (line 63) * MySQL Cluster Disk Data, creating tables: mysql-cluster-disk-data-objects. (line 43) * MySQL Cluster Disk Data, creating tablespaces: mysql-cluster-disk-data-objects. (line 127) * MySQL Cluster Disk Data, dropping Disk Data objects: mysql-cluster-disk-data-objects. (line 253) * MySQL Cluster Disk Data, storage requirements: mysql-cluster-disk-data-storage-requirements. (line 6) * MySQL Cluster How-To: mysql-cluster-installation. (line 16) * MySQL Cluster in MySQL 5.1: mysql-cluster-development. (line 16) * MySQL Cluster limitations: mysql-cluster-limitations. (line 20) * MySQL Cluster limitations, and differences from standard MySQL limits: mysql-cluster-limitations-limits. (line 6) * MySQL Cluster limitations, autodiscovery: mysql-cluster-limitations-resolved. (line 53) * MySQL Cluster limitations, binary logging: mysql-cluster-limitations-exclusive-to-cluster. (line 22) * MySQL Cluster limitations, character sets: mysql-cluster-limitations-resolved. (line 84) * MySQL Cluster limitations, CREATE TABLE statements: mysql-cluster-limitations-resolved. (line 133) * MySQL Cluster limitations, database objects: mysql-cluster-limitations-database-objects. (line 6) * MySQL Cluster limitations, Disk Data storage: mysql-cluster-limitations-disk-data. (line 6) * MySQL Cluster limitations, error handling and reporting: mysql-cluster-limitations-error-handling. (line 6) * MySQL Cluster limitations, geometry data types: mysql-cluster-limitations-syntax. (line 86) * MySQL Cluster limitations, implementation: mysql-cluster-limitations-exclusive-to-cluster. (line 6) * MySQL Cluster limitations, imposed by configuration: mysql-cluster-limitations-limits. (line 39) * MySQL Cluster limitations, INSERT IGNORE, UPDATE IGNORE, and REPLACE statements: mysql-cluster-limitations-resolved. (line 139) * MySQL Cluster limitations, memory usage and transaction handling: mysql-cluster-limitations-transactions. (line 109) * MySQL Cluster limitations, multiple data nodes <1>: mysql-cluster-limitations-resolved. (line 108) * MySQL Cluster limitations, multiple data nodes: mysql-cluster-development-5-1-ndb-6-2. (line 140) * MySQL Cluster limitations, multiple management servers <1>: mysql-cluster-limitations-resolved. (line 94) * MySQL Cluster limitations, multiple management servers: mysql-cluster-limitations-multiple-nodes. (line 29) * MySQL Cluster limitations, multiple MySQL servers: mysql-cluster-limitations-multiple-nodes. (line 8) * MySQL Cluster limitations, partitioning: mysql-cluster-limitations-syntax. (line 106) * MySQL Cluster limitations, performance: mysql-cluster-limitations-performance. (line 6) * MySQL Cluster limitations, replication <1>: mysql-cluster-limitations-resolved. (line 35) * MySQL Cluster limitations, replication: mysql-cluster-limitations-syntax. (line 161) * MySQL Cluster limitations, resolved in current version from previous versions: mysql-cluster-limitations-resolved. (line 6) * MySQL Cluster limitations, syntax: mysql-cluster-limitations-syntax. (line 6) * MySQL Cluster limitations, transactions: mysql-cluster-limitations-transactions. (line 6) * MySQL Cluster limitations, unsupported features: mysql-cluster-limitations-unsupported. (line 6) * MySQL Cluster NDB 6.x: mysql-cluster-development. (line 16) * MySQL Cluster NDB 7.x: mysql-cluster-development. (line 16) * MySQL Cluster processes: mysql-cluster-programs. (line 32) * MySQL Cluster programs: mysql-cluster-programs. (line 32) * MySQL Cluster replication: mysql-cluster-replication. (line 20) * MySQL Cluster replication, and -initial option: mysql-cluster-replication-issues. (line 211) * MySQL Cluster replication, and auto_increment* variables: mysql-cluster-replication-issues. (line 222) * MySQL Cluster replication, and circular replication: mysql-cluster-replication-issues. (line 76) * MySQL Cluster replication, and multi-byte character sets: mysql-cluster-replication-issues. (line 69) * MySQL Cluster replication, and primary key: mysql-cluster-replication-issues. (line 145) * MySQL Cluster replication, and single point of failure: mysql-cluster-replication-two-channels. (line 6) * MySQL Cluster replication, and unique keys: mysql-cluster-replication-issues. (line 156) * MySQL Cluster replication, backups: mysql-cluster-replication-backups. (line 11) * MySQL Cluster replication, circular replication: mysql-cluster-replication-multi-master. (line 6) * MySQL Cluster replication, concepts <1>: mysql-cluster-replication-general. (line 6) * MySQL Cluster replication, concepts: mysql-cluster-replication-abbreviations. (line 6) * MySQL Cluster replication, conflict resolution: mysql-cluster-replication-conflict-resolution. (line 6) * MySQL Cluster replication, failover <1>: mysql-cluster-replication-failover. (line 6) * MySQL Cluster replication, failover: mysql-cluster-replication-two-channels. (line 6) * MySQL Cluster replication, gap event: mysql-cluster-replication-issues. (line 36) * MySQL Cluster replication, known issues: mysql-cluster-replication-issues. (line 6) * MySQL Cluster replication, loss of connection: mysql-cluster-replication-issues. (line 12) * MySQL Cluster replication, multi-master replication: mysql-cluster-replication-multi-master. (line 6) * MySQL Cluster replication, point-in-time recovery: mysql-cluster-replication-pitr. (line 6) * MySQL Cluster replication, preparing: mysql-cluster-replication-preparation. (line 6) * MySQL Cluster replication, requirements: mysql-cluster-replication-general. (line 6) * MySQL Cluster replication, reset-slave.pl backup automation script: mysql-cluster-replication-auto-sync. (line 11) * MySQL Cluster replication, restoring from backup: mysql-cluster-replication-backups. (line 11) * MySQL Cluster replication, starting: mysql-cluster-replication-starting. (line 6) * MySQL Cluster replication, storage engines other than NDB on slave: mysql-cluster-replication-issues. (line 230) * MySQL Cluster replication, synchronization of master and slave: mysql-cluster-replication-auto-sync. (line 6) * MySQL Cluster replication, system tables used: mysql-cluster-replication-schema. (line 6) * MySQL Cluster, "quick" configuration: mysql-cluster-quick. (line 6) * MySQL Cluster, administration <1>: mysql-cluster-log-statistics. (line 6) * MySQL Cluster, administration <2>: mysql-cluster-mgm-client-commands. (line 6) * MySQL Cluster, administration <3>: mysql-cluster-program-options-common. (line 6) * MySQL Cluster, administration <4>: mysql-cluster-programs-ndb-mgm. (line 6) * MySQL Cluster, administration <5>: mysql-cluster-programs-ndb-mgmd. (line 12) * MySQL Cluster, administration <6>: mysql-cluster-programs-ndbd. (line 17) * MySQL Cluster, administration: mysql-cluster-program-options-mysqld. (line 6) * MySQL Cluster, and application feature requirements: mysql-cluster-ndb-innodb-usage. (line 6) * MySQL Cluster, and character sets: mysql-cluster-replication-issues. (line 69) * MySQL Cluster, and DNS: mysql-cluster-installation. (line 55) * MySQL Cluster, and INFORMATION_SCHEMA: mysql-cluster-security-mysql-privileges. (line 118) * MySQL Cluster, and IP addressing: mysql-cluster-installation. (line 55) * MySQL Cluster, and MySQL privileges: mysql-cluster-security-mysql-privileges. (line 6) * MySQL Cluster, and MySQL root user <1>: mysql-cluster-security-mysql-security-procedures. (line 50) * MySQL Cluster, and MySQL root user: mysql-cluster-security-mysql-privileges. (line 51) * MySQL Cluster, and networking: mysql-cluster-overview-requirements. (line 6) * MySQL Cluster, and transactions <1>: faqs-mysql-cluster. (line 6) * MySQL Cluster, and transactions: mysql-cluster-ndbd-definition. (line 443) * MySQL Cluster, and virtual machines: faqs-mysql-cluster. (line 6) * MySQL Cluster, API node <1>: mysql-cluster-api-definition. (line 6) * MySQL Cluster, API node: mysql-cluster-basics. (line 6) * MySQL Cluster, applications supported: mysql-cluster-ndb-innodb-workloads. (line 6) * MySQL Cluster, arbitrator: faqs-mysql-cluster. (line 6) * MySQL Cluster, availability: mysql-cluster-compared. (line 36) * MySQL Cluster, available platforms: mysql-cluster. (line 66) * MySQL Cluster, backups <1>: mysql-cluster-backup-troubleshooting. (line 6) * MySQL Cluster, backups <2>: mysql-cluster-backup-configuration. (line 6) * MySQL Cluster, backups <3>: mysql-cluster-backup-using-management-client. (line 6) * MySQL Cluster, backups <4>: mysql-cluster-backup-concepts. (line 6) * MySQL Cluster, backups <5>: mysql-cluster-backup. (line 13) * MySQL Cluster, backups: mysql-cluster-programs-ndb-restore. (line 6) * MySQL Cluster, benchmarks: mysql-cluster-interconnects-performance. (line 6) * MySQL Cluster, CHECKPOINT Events: mysql-cluster-log-events. (line 35) * MySQL Cluster, cluster logs <1>: mysql-cluster-logging-management-commands. (line 6) * MySQL Cluster, cluster logs: mysql-cluster-event-reports. (line 12) * MySQL Cluster, CLUSTERLOG commands: mysql-cluster-logging-management-commands. (line 8) * MySQL Cluster, CLUSTERLOG STATISTICS command: mysql-cluster-log-statistics. (line 6) * MySQL Cluster, commands <1>: mysql-cluster-mgm-client-commands. (line 6) * MySQL Cluster, commands <2>: mysql-cluster-programs-ndb-mgm. (line 27) * MySQL Cluster, commands <3>: mysql-cluster-programs-ndb-mgmd. (line 12) * MySQL Cluster, commands <4>: mysql-cluster-programs-ndbd. (line 17) * MySQL Cluster, commands: mysql-cluster-program-options-mysqld. (line 6) * MySQL Cluster, compared to InnoDB <1>: mysql-cluster-ndb-innodb-usage. (line 6) * MySQL Cluster, compared to InnoDB <2>: mysql-cluster-ndb-innodb-workloads. (line 6) * MySQL Cluster, compared to InnoDB <3>: mysql-cluster-ndb-innodb-engines. (line 6) * MySQL Cluster, compared to InnoDB: mysql-cluster-compared. (line 12) * MySQL Cluster, compared to standalone MySQL Server <1>: mysql-cluster-ndb-innodb-usage. (line 6) * MySQL Cluster, compared to standalone MySQL Server <2>: mysql-cluster-ndb-innodb-workloads. (line 6) * MySQL Cluster, compared to standalone MySQL Server <3>: mysql-cluster-ndb-innodb-engines. (line 6) * MySQL Cluster, compared to standalone MySQL Server: mysql-cluster-compared. (line 12) * MySQL Cluster, compiling with icc: porting. (line 32) * MySQL Cluster, concepts: mysql-cluster-basics. (line 6) * MySQL Cluster, configuration <1>: mysql-cluster-programs-ndb-mgmd. (line 495) * MySQL Cluster, configuration <2>: mysql-cluster-programs-mysqld. (line 49) * MySQL Cluster, configuration <3>: mysql-cluster-config-lcp-params. (line 6) * MySQL Cluster, configuration <4>: mysql-cluster-api-definition. (line 6) * MySQL Cluster, configuration <5>: mysql-cluster-ndbd-definition. (line 6) * MySQL Cluster, configuration <6>: mysql-cluster-mgm-definition. (line 6) * MySQL Cluster, configuration <7>: mysql-cluster-computer-definition. (line 6) * MySQL Cluster, configuration <8>: mysql-cluster-quick. (line 6) * MySQL Cluster, configuration <9>: mysql-cluster-configuration. (line 14) * MySQL Cluster, configuration: mysql-cluster-installation. (line 16) * MySQL Cluster, configuration (example): mysql-cluster-config-example. (line 6) * MySQL Cluster, configuration changes: mysql-cluster-rolling-restart. (line 20) * MySQL Cluster, configuration files <1>: mysql-cluster-config-file. (line 22) * MySQL Cluster, configuration files: mysql-cluster-install-configuration. (line 6) * MySQL Cluster, configuration parameters <1>: mysql-cluster-params-other. (line 6) * MySQL Cluster, configuration parameters <2>: mysql-cluster-params-api. (line 6) * MySQL Cluster, configuration parameters <3>: mysql-cluster-params-mgmd. (line 6) * MySQL Cluster, configuration parameters <4>: mysql-cluster-params-ndbd. (line 6) * MySQL Cluster, configuration parameters: mysql-cluster-params-overview. (line 13) * MySQL Cluster, configuring: mysql-cluster-backup-configuration. (line 6) * MySQL Cluster, CONNECTION Events: mysql-cluster-log-events. (line 20) * MySQL Cluster, connectstring: mysql-cluster-connectstring. (line 6) * MySQL Cluster, CREATE NODEGROUP command: mysql-cluster-mgm-client-commands. (line 191) * MySQL Cluster, creating large tables: create-table. (line 814) * MySQL Cluster, data node <1>: mysql-cluster-ndbd-definition. (line 6) * MySQL Cluster, data node: mysql-cluster-basics. (line 6) * MySQL Cluster, data nodes <1>: mysql-cluster-programs-ndbmtd. (line 6) * MySQL Cluster, data nodes: mysql-cluster-programs-ndbd. (line 6) * MySQL Cluster, data types supported: faqs-mysql-cluster. (line 6) * MySQL Cluster, defining node hosts: mysql-cluster-computer-definition. (line 6) * MySQL Cluster, direct connections between nodes: mysql-cluster-tcp-definition-direct. (line 6) * MySQL Cluster, Disk Data tables: mysql-cluster-disk-data. (line 12) * MySQL Cluster, DROP NODEGROUP command: mysql-cluster-mgm-client-commands. (line 214) * MySQL Cluster, ENTER SINGLE USER MODE command: mysql-cluster-mgm-client-commands. (line 158) * MySQL Cluster, ERROR Events: mysql-cluster-log-events. (line 196) * MySQL Cluster, error logs: mysql-cluster-programs-ndbd. (line 358) * MySQL Cluster, error messages: faqs-mysql-cluster. (line 6) * MySQL Cluster, event log format: mysql-cluster-log-events. (line 6) * MySQL Cluster, event logging thresholds: mysql-cluster-logging-management-commands. (line 34) * MySQL Cluster, event logs <1>: mysql-cluster-logging-management-commands. (line 6) * MySQL Cluster, event logs: mysql-cluster-event-reports. (line 12) * MySQL Cluster, event severity levels: mysql-cluster-logging-management-commands. (line 55) * MySQL Cluster, event types <1>: mysql-cluster-log-events. (line 20) * MySQL Cluster, event types: mysql-cluster-event-reports. (line 49) * MySQL Cluster, execution threads: mysql-cluster-programs-ndbmtd. (line 66) * MySQL Cluster, EXIT command: mysql-cluster-mgm-client-commands. (line 176) * MySQL Cluster, EXIT SINGLE USER MODE command: mysql-cluster-mgm-client-commands. (line 166) * MySQL Cluster, FAQ: faqs-mysql-cluster. (line 6) * MySQL Cluster, features added in MySQL 5.1: mysql-cluster-development-5-1. (line 6) * MySQL Cluster, GCP Stop errors: mysql-cluster-ndbd-definition. (line 3731) * MySQL Cluster, general description: mysql-cluster-overview. (line 15) * MySQL Cluster, hardware requirements: faqs-mysql-cluster. (line 6) * MySQL Cluster, HELP command: mysql-cluster-mgm-client-commands. (line 20) * MySQL Cluster, HostName parameter, and security: mysql-cluster-security-networking-issues. (line 40) * MySQL Cluster, how to obtain: faqs-mysql-cluster. (line 6) * MySQL Cluster, importing existing tables: faqs-mysql-cluster. (line 6) * MySQL Cluster, INFO Events: mysql-cluster-log-events. (line 210) * MySQL Cluster, information sources: mysql-cluster. (line 227) * MySQL Cluster, insecurity of communication protocols: mysql-cluster-security-networking-issues. (line 12) * MySQL Cluster, installation: mysql-cluster-installation. (line 16) * MySQL Cluster, installation (Linux): mysql-cluster-install-linux. (line 12) * MySQL Cluster, installation (Windows): mysql-cluster-install-windows. (line 13) * MySQL Cluster, installing binary (Windows): mysql-cluster-install-windows-binary. (line 6) * MySQL Cluster, installing binary release (Linux): mysql-cluster-install-linux-binary. (line 6) * MySQL Cluster, installing from source (Linux): mysql-cluster-install-linux-source. (line 6) * MySQL Cluster, installing from source (Windows): mysql-cluster-install-windows-source. (line 6) * MySQL Cluster, installing RPM (Linux): mysql-cluster-install-linux-rpm. (line 6) * MySQL Cluster, interconnects: mysql-cluster-interconnects. (line 11) * MySQL Cluster, Java clients: mysql-cluster-basics. (line 116) * MySQL Cluster, log files <1>: mysql-cluster-programs-ndbmtd. (line 134) * MySQL Cluster, log files: mysql-cluster-programs-ndbd. (line 349) * MySQL Cluster, logging commands: mysql-cluster-logging-management-commands. (line 6) * MySQL Cluster, management client (ndb_mgm): mysql-cluster-programs-ndb-mgm. (line 6) * MySQL Cluster, management commands: mysql-cluster-log-statistics. (line 6) * MySQL Cluster, management node <1>: mysql-cluster-mgm-definition. (line 6) * MySQL Cluster, management node: mysql-cluster-basics. (line 6) * MySQL Cluster, management nodes: mysql-cluster-programs-ndb-mgmd. (line 6) * MySQL Cluster, managing: mysql-cluster-management. (line 22) * MySQL Cluster, master node: faqs-mysql-cluster. (line 6) * MySQL Cluster, MAX_ROWS: create-table. (line 814) * MySQL Cluster, memory requirements: faqs-mysql-cluster. (line 6) * MySQL Cluster, memory usage and recovery <1>: mysql-cluster-rolling-restart. (line 64) * MySQL Cluster, memory usage and recovery: mysql-cluster-limitations-limits. (line 9) * MySQL Cluster, mgm: mysql-cluster-program-options-common. (line 6) * MySQL Cluster, mgm client: mysql-cluster-mgm-client-commands. (line 6) * MySQL Cluster, mgm management client: mysql-cluster-log-statistics. (line 6) * MySQL Cluster, mgm process: mysql-cluster-programs-ndb-mgm. (line 27) * MySQL Cluster, mgmd: mysql-cluster-program-options-common. (line 6) * MySQL Cluster, mgmd process: mysql-cluster-programs-ndb-mgmd. (line 12) * MySQL Cluster, mysqld options and variables for: mysql-cluster-options-variables. (line 13) * MySQL Cluster, mysqld process <1>: mysql-cluster-programs-mysqld. (line 6) * MySQL Cluster, mysqld process: mysql-cluster-program-options-mysqld. (line 6) * MySQL Cluster, ndb_mgm <1>: mysql-cluster-programs-ndb-mgm. (line 6) * MySQL Cluster, ndb_mgm: mysql-cluster-install-first-start. (line 34) * MySQL Cluster, ndb_mgmd process: mysql-cluster-programs-ndb-mgmd. (line 6) * MySQL Cluster, ndb_size.pl (utility): faqs-mysql-cluster. (line 6) * MySQL Cluster, ndbd <1>: mysql-cluster-program-options-common. (line 6) * MySQL Cluster, ndbd: mysql-cluster-programs-ndbd. (line 6) * MySQL Cluster, ndbd process <1>: mysql-cluster-log-statistics. (line 164) * MySQL Cluster, ndbd process: mysql-cluster-programs-ndbd. (line 17) * MySQL Cluster, ndbmtd: mysql-cluster-programs-ndbmtd. (line 6) * MySQL Cluster, network configuration, and security: mysql-cluster-security-networking-issues. (line 59) * MySQL Cluster, network transporters <1>: mysql-cluster-sci-sockets. (line 6) * MySQL Cluster, network transporters: mysql-cluster-interconnects. (line 11) * MySQL Cluster, networking <1>: mysql-cluster-sci-definition. (line 6) * MySQL Cluster, networking <2>: mysql-cluster-shm-definition. (line 6) * MySQL Cluster, networking: mysql-cluster-tcp-definition-direct. (line 6) * MySQL Cluster, networking requirements: faqs-mysql-cluster. (line 6) * MySQL Cluster, node failure (single user mode): mysql-cluster-single-user-mode. (line 52) * MySQL Cluster, node identifiers <1>: mysql-cluster-sci-definition. (line 26) * MySQL Cluster, node identifiers: mysql-cluster-shm-definition. (line 25) * MySQL Cluster, node logs: mysql-cluster-event-reports. (line 12) * MySQL Cluster, node types: faqs-mysql-cluster. (line 6) * MySQL Cluster, NODERESTART Events: mysql-cluster-log-events. (line 89) * MySQL Cluster, nodes and node groups: mysql-cluster-nodes-groups. (line 6) * MySQL Cluster, nodes and types: mysql-cluster-basics. (line 6) * MySQL Cluster, number of computers required: faqs-mysql-cluster. (line 6) * MySQL Cluster, partitioning support: mysql-cluster-limitations-syntax. (line 106) * MySQL Cluster, partitions: mysql-cluster-nodes-groups. (line 6) * MySQL Cluster, performance: mysql-cluster-interconnects-performance. (line 6) * MySQL Cluster, performing queries: mysql-cluster-install-example-data. (line 6) * MySQL Cluster, platforms supported: faqs-mysql-cluster. (line 6) * MySQL Cluster, preparing for replication: mysql-cluster-replication-preparation. (line 6) * MySQL Cluster, process management: mysql-cluster-programs. (line 32) * MySQL Cluster, QUIT command: mysql-cluster-mgm-client-commands. (line 176) * MySQL Cluster, replicas: mysql-cluster-nodes-groups. (line 6) * MySQL Cluster, replication: mysql-cluster-replication. (line 20) * MySQL Cluster, REPORT command: mysql-cluster-mgm-client-commands. (line 126) * MySQL Cluster, requirements: mysql-cluster-overview-requirements. (line 6) * MySQL Cluster, resetting: mysql-cluster-rolling-restart. (line 38) * MySQL Cluster, RESTART command: mysql-cluster-mgm-client-commands. (line 87) * MySQL Cluster, restarting: mysql-cluster-install-shutdown-restart. (line 6) * MySQL Cluster, restoring backups: mysql-cluster-programs-ndb-restore. (line 6) * MySQL Cluster, roles of computers: faqs-mysql-cluster. (line 6) * MySQL Cluster, runtime statistics: mysql-cluster-log-statistics. (line 6) * MySQL Cluster, SCI (Scalable Coherent Interface) <1>: mysql-cluster-sci-sockets. (line 6) * MySQL Cluster, SCI (Scalable Coherent Interface): mysql-cluster-sci-definition. (line 6) * MySQL Cluster, security <1>: faqs-mysql-cluster. (line 6) * MySQL Cluster, security: mysql-cluster-security. (line 12) * MySQL Cluster, security procedures: mysql-cluster-security-mysql-security-procedures. (line 6) * MySQL Cluster, security, and firewalls: mysql-cluster-security-networking-issues. (line 98) * MySQL Cluster, security, and HostName parameter: mysql-cluster-security-networking-issues. (line 40) * MySQL Cluster, security, and network configuration: mysql-cluster-security-networking-issues. (line 59) * MySQL Cluster, security, and network ports: mysql-cluster-security-networking-issues. (line 182) * MySQL Cluster, security, and remote administration: mysql-cluster-security-networking-issues. (line 189) * MySQL Cluster, security, networking: mysql-cluster-security-networking-issues. (line 6) * MySQL Cluster, shared memory transport: mysql-cluster-shm-definition. (line 6) * MySQL Cluster, SHOW command: mysql-cluster-mgm-client-commands. (line 24) * MySQL Cluster, SHUTDOWN command: mysql-cluster-mgm-client-commands. (line 182) * MySQL Cluster, shutting down: mysql-cluster-install-shutdown-restart. (line 6) * MySQL Cluster, single user mode <1>: mysql-cluster-single-user-mode. (line 6) * MySQL Cluster, single user mode: mysql-cluster-mgm-client-commands. (line 158) * MySQL Cluster, SQL node <1>: mysql-cluster-api-definition. (line 6) * MySQL Cluster, SQL node: mysql-cluster-basics. (line 6) * MySQL Cluster, SQL nodes: mysql-cluster-programs-mysqld. (line 6) * MySQL Cluster, SQL statements: faqs-mysql-cluster. (line 6) * MySQL Cluster, SQL statements for monitoring: mysql-cluster-sql-statements. (line 6) * MySQL Cluster, START BACKUP command: mysql-cluster-replication-backups. (line 40) * MySQL Cluster, START command: mysql-cluster-mgm-client-commands. (line 43) * MySQL Cluster, start phases (summary): mysql-cluster-start-phases. (line 6) * MySQL Cluster, starting: mysql-cluster-quick. (line 6) * MySQL Cluster, starting and stopping: faqs-mysql-cluster. (line 6) * MySQL Cluster, starting nodes <1>: mysql-cluster-install-first-start. (line 6) * MySQL Cluster, starting nodes: mysql-cluster-install-windows-initial-start. (line 6) * MySQL Cluster, starting or restarting: mysql-cluster-start-phases. (line 6) * MySQL Cluster, STARTUP Events: mysql-cluster-log-events. (line 54) * MySQL Cluster, STATISTICS Events: mysql-cluster-log-events. (line 172) * MySQL Cluster, STATUS command: mysql-cluster-mgm-client-commands. (line 117) * MySQL Cluster, STOP command: mysql-cluster-mgm-client-commands. (line 58) * MySQL Cluster, storage requirements: storage-requirements. (line 35) * MySQL Cluster, Table is full errors: faqs-mysql-cluster. (line 6) * MySQL Cluster, thread states: mysql-cluster-thread-states. (line 6) * MySQL Cluster, trace files: mysql-cluster-programs-ndbd. (line 390) * MySQL Cluster, transaction handling: mysql-cluster-limitations-transactions. (line 109) * MySQL Cluster, transporters, Scalable Coherent Interface (SCI): mysql-cluster-sci-definition. (line 6) * MySQL Cluster, transporters, shared memory (SHM): mysql-cluster-shm-definition. (line 6) * MySQL Cluster, transporters, TCP/IP: mysql-cluster-tcp-definition-direct. (line 6) * MySQL Cluster, troubleshooting backups: mysql-cluster-backup-troubleshooting. (line 6) * MySQL Cluster, upgrades and downgrades <1>: mysql-cluster-rolling-restart. (line 6) * MySQL Cluster, upgrades and downgrades: mysql-cluster-upgrade-downgrade. (line 12) * MySQL Cluster, using tables and data: mysql-cluster-install-example-data. (line 6) * MySQL Cluster, vs replication: faqs-mysql-cluster. (line 6) * mysql command options: mysql-command-options. (line 6) * mysql commands, list of: mysql-commands. (line 11) * MySQL Dolphin name: history. (line 6) * MySQL history: history. (line 6) * mysql history file: mysql-history-file. (line 6) * MySQL Instance Manager: instance-manager. (line 16) * MySQL mailing lists: mailing-lists. (line 10) * MySQL name: history. (line 6) * MySQL privileges, and MySQL Cluster: mysql-cluster-security-mysql-privileges. (line 10) * mysql prompt command: mysql-commands. (line 291) * MySQL server, mysqld <1>: mysqld-server. (line 19) * MySQL server, mysqld: mysqld. (line 6) * mysql source (command for reading from text files) <1>: batch-commands. (line 6) * mysql source (command for reading from text files): batch-mode. (line 90) * MySQL source distribution: which-version. (line 18) * MySQL storage engines: storage-engines. (line 23) * MySQL system tables, and MySQL Cluster: mysql-cluster-security-mysql-privileges. (line 23) * MySQL system tables, and replication: replication-features-mysqldb. (line 6) * MySQL version: getting-mysql. (line 6) * mysql, auto-rehash option: mysql-command-options. (line 157) * mysql, batch option: mysql-command-options. (line 171) * mysql, bind-address option: mysql-command-options. (line 181) * mysql, character-sets-dir option: mysql-command-options. (line 192) * mysql, charset command: mysql-commands. (line 61) * mysql, clear command: mysql-commands. (line 70) * mysql, column-names option: mysql-command-options. (line 197) * mysql, column-type-info option: mysql-command-options. (line 201) * mysql, comments option: mysql-command-options. (line 207) * mysql, compress option: mysql-command-options. (line 214) * mysql, connect command: mysql-commands. (line 75) * mysql, database option: mysql-command-options. (line 219) * mysql, debug option: mysql-command-options. (line 223) * mysql, debug-check option: mysql-command-options. (line 228) * mysql, debug-info option: mysql-command-options. (line 233) * mysql, default-character-set option: mysql-command-options. (line 241) * MySQL, defined: what-is-mysql. (line 6) * mysql, delimiter command: mysql-commands. (line 82) * mysql, delimiter option: mysql-command-options. (line 255) * mysql, disable named commands: mysql-command-options. (line 260) * mysql, edit command: mysql-commands. (line 117) * mysql, ego command: mysql-commands. (line 126) * mysql, execute option: mysql-command-options. (line 268) * mysql, exit command: mysql-commands. (line 131) * mysql, force option: mysql-command-options. (line 275) * mysql, go command: mysql-commands. (line 135) * mysql, help command: mysql-commands. (line 51) * mysql, help option: mysql-command-options. (line 153) * mysql, host option: mysql-command-options. (line 279) * mysql, html option: mysql-command-options. (line 283) * mysql, i-am-a-dummy option: mysql-command-options. (line 467) * mysql, ignore-spaces option: mysql-command-options. (line 287) * MySQL, introduction: what-is-mysql. (line 6) * mysql, line-numbers option: mysql-command-options. (line 293) * mysql, local-infile option: mysql-command-options. (line 298) * mysql, named-commands option: mysql-command-options. (line 306) * mysql, no-auto-rehash option: mysql-command-options. (line 313) * mysql, no-beep option: mysql-command-options. (line 318) * mysql, no-named-commands option: mysql-command-options. (line 322) * mysql, no-pager option: mysql-command-options. (line 327) * mysql, no-tee option: mysql-command-options. (line 332) * mysql, nopager command: mysql-commands. (line 139) * mysql, notee command: mysql-commands. (line 145) * mysql, nowarning command: mysql-commands. (line 150) * mysql, one-database option: mysql-command-options. (line 337) * mysql, pager command: mysql-commands. (line 154) * mysql, pager option: mysql-command-options. (line 380) * mysql, password option: mysql-command-options. (line 389) * mysql, pipe option: mysql-command-options. (line 401) * mysql, port option: mysql-command-options. (line 406) * mysql, print command: mysql-commands. (line 176) * mysql, prompt command: mysql-commands. (line 180) * mysql, prompt option: mysql-command-options. (line 410) * MySQL, pronunciation: what-is-mysql. (line 84) * mysql, protocol option: mysql-command-options. (line 416) * mysql, quick option: mysql-command-options. (line 423) * mysql, quit command: mysql-commands. (line 189) * mysql, raw option: mysql-command-options. (line 429) * mysql, reconnect option: mysql-command-options. (line 460) * mysql, rehash command: mysql-commands. (line 193) * mysql, safe-updates option: mysql-command-options. (line 467) * mysql, secure-auth option: mysql-command-options. (line 475) * mysql, show-warnings option: mysql-command-options. (line 481) * mysql, sigint-ignore option: mysql-command-options. (line 486) * mysql, silent option: mysql-command-options. (line 490) * mysql, skip-column-names option: mysql-command-options. (line 499) * mysql, skip-line-numbers option: mysql-command-options. (line 503) * mysql, socket option: mysql-command-options. (line 508) * mysql, source command: mysql-commands. (line 199) * mysql, SSL options: mysql-command-options. (line 513) * mysql, status command: mysql-commands. (line 204) * mysql, system command: mysql-commands. (line 211) * mysql, table option: mysql-command-options. (line 519) * mysql, tee command: mysql-commands. (line 217) * mysql, tee option: mysql-command-options. (line 525) * mysql, unbuffered option: mysql-command-options. (line 531) * MySQL, upgrading: mysql-upgrade. (line 6) * mysql, use command: mysql-commands. (line 231) * mysql, user option: mysql-command-options. (line 535) * mysql, verbose option: mysql-command-options. (line 539) * mysql, version option: mysql-command-options. (line 546) * mysql, vertical option: mysql-command-options. (line 550) * mysql, wait option: mysql-command-options. (line 556) * mysql, warnings command: mysql-commands. (line 235) * mysql, xml option: mysql-command-options. (line 561) * mysql.event table: events-privileges. (line 145) * mysql.ndb_binlog_index table: mysql-cluster-replication-schema. (line 6) * mysql.server <1>: mysql-server. (line 6) * mysql.server: programs-overview. (line 50) * mysql.server, basedir option: mysql-server. (line 36) * mysql.server, datadir option: mysql-server. (line 40) * mysql.server, pid-file option: mysql-server. (line 44) * mysql.server, service-startup-timeout option: mysql-server. (line 49) * mysql.server, use-manager option: mysql-server. (line 63) * mysql.server, use-mysqld_safe option: mysql-server. (line 58) * mysql.server, user option: mysql-server. (line 67) * mysql.sock, changing location of: source-configuration-options. (line 377) * mysql.sock, protection: problems-with-mysql-sock. (line 6) * MYSQL323 SQL mode: server-sql-mode. (line 481) * MYSQL40 SQL mode: server-sql-mode. (line 485) * mysql_affected_rows(): mysql-affected-rows. (line 6) * mysql_autocommit(): mysql-autocommit. (line 6) * MYSQL_BIND C type: c-api-prepared-statement-data-structures. (line 51) * mysql_change_user(): mysql-change-user. (line 6) * mysql_character_set_name(): mysql-character-set-name. (line 6) * mysql_close(): mysql-close. (line 6) * mysql_cluster_move_privileges: mysql-cluster-privilege-distribution. (line 54) * mysql_cluster_privileges_are_distributed: mysql-cluster-privilege-distribution. (line 83) * mysql_commit(): mysql-commit. (line 6) * mysql_config: mysql-config. (line 6) * mysql_config, cflags option: mysql-config. (line 11) * mysql_config, embedded option: mysql-config. (line 24) * mysql_config, include option: mysql-config. (line 20) * mysql_config, libmysqld-libs option: mysql-config. (line 24) * mysql_config, libs option: mysql-config. (line 29) * mysql_config, libs_r option: mysql-config. (line 34) * mysql_config, plugindir option: mysql-config. (line 39) * mysql_config, port option: mysql-config. (line 44) * mysql_config, socket option: mysql-config. (line 48) * mysql_config, version option: mysql-config. (line 52) * mysql_connect(): mysql-connect. (line 6) * mysql_convert_table_format <1>: mysql-convert-table-format. (line 6) * mysql_convert_table_format: programs-overview. (line 221) * mysql_convert_table_format, force option: mysql-convert-table-format. (line 28) * mysql_convert_table_format, help option: mysql-convert-table-format. (line 24) * mysql_convert_table_format, host option: mysql-convert-table-format. (line 32) * mysql_convert_table_format, password option: mysql-convert-table-format. (line 36) * mysql_convert_table_format, port option: mysql-convert-table-format. (line 46) * mysql_convert_table_format, socket option: mysql-convert-table-format. (line 50) * mysql_convert_table_format, type option: mysql-convert-table-format. (line 54) * mysql_convert_table_format, user option: mysql-convert-table-format. (line 59) * mysql_convert_table_format, verbose option: mysql-convert-table-format. (line 63) * mysql_convert_table_format, version option: mysql-convert-table-format. (line 67) * mysql_create_db(): mysql-create-db. (line 6) * mysql_data_seek(): mysql-data-seek. (line 6) * MYSQL_DEBUG environment variable <1>: debugging-client. (line 10) * MYSQL_DEBUG environment variable <2>: programs-overview. (line 317) * MYSQL_DEBUG environment variable: environment-variables. (line 18) * mysql_debug(): mysql-debug. (line 6) * mysql_drop_db(): mysql-drop-db. (line 6) * mysql_dump_debug_info(): mysql-dump-debug-info. (line 6) * mysql_eof(): mysql-eof. (line 6) * mysql_errno(): mysql-errno. (line 6) * mysql_error(): mysql-error. (line 6) * mysql_escape_string(): mysql-escape-string. (line 6) * mysql_fetch_field(): mysql-fetch-field. (line 6) * mysql_fetch_field_direct(): mysql-fetch-field-direct. (line 6) * mysql_fetch_fields(): mysql-fetch-fields. (line 6) * mysql_fetch_lengths(): mysql-fetch-lengths. (line 6) * mysql_fetch_row(): mysql-fetch-row. (line 6) * MYSQL_FIELD C type: c-api-data-structures. (line 34) * mysql_field_count() <1>: mysql-num-fields. (line 6) * mysql_field_count(): mysql-field-count. (line 6) * MYSQL_FIELD_OFFSET C type: c-api-data-structures. (line 43) * mysql_field_seek(): mysql-field-seek. (line 6) * mysql_field_tell(): mysql-field-tell. (line 6) * mysql_find_rows <1>: mysql-find-rows. (line 6) * mysql_find_rows: programs-overview. (line 226) * mysql_find_rows, help option: mysql-find-rows. (line 31) * mysql_find_rows, regexp option: mysql-find-rows. (line 35) * mysql_find_rows, rows option: mysql-find-rows. (line 39) * mysql_find_rows, skip-use-db option: mysql-find-rows. (line 43) * mysql_find_rows, start_row option: mysql-find-rows. (line 47) * mysql_fix_extensions <1>: mysql-fix-extensions. (line 6) * mysql_fix_extensions: programs-overview. (line 232) * mysql_fix_privilege_tables <1>: mysql-fix-privilege-tables. (line 6) * mysql_fix_privilege_tables: programs-overview. (line 86) * mysql_free_result(): mysql-free-result. (line 6) * mysql_get_character_set_info(): mysql-get-character-set-info. (line 6) * mysql_get_client_info(): mysql-get-client-info. (line 6) * mysql_get_client_version(): mysql-get-client-version. (line 6) * mysql_get_host_info(): mysql-get-host-info. (line 6) * mysql_get_proto_info(): mysql-get-proto-info. (line 6) * mysql_get_server_info(): mysql-get-server-info. (line 6) * mysql_get_server_version(): mysql-get-server-version. (line 6) * mysql_get_ssl_cipher(): mysql-get-ssl-cipher. (line 6) * MYSQL_GROUP_SUFFIX environment variable: environment-variables. (line 18) * mysql_hex_string(): mysql-hex-string. (line 6) * MYSQL_HISTFILE environment variable <1>: mysql-history-file. (line 6) * MYSQL_HISTFILE environment variable: environment-variables. (line 18) * MYSQL_HOME environment variable: environment-variables. (line 18) * MYSQL_HOST environment variable <1>: connecting. (line 231) * MYSQL_HOST environment variable: environment-variables. (line 18) * mysql_info() <1>: mysql-info. (line 6) * mysql_info() <2>: update. (line 86) * mysql_info() <3>: load-data. (line 668) * mysql_info() <4>: insert. (line 202) * mysql_info(): alter-table. (line 528) * mysql_init(): mysql-init. (line 6) * mysql_insert_id() <1>: mysql-insert-id. (line 6) * mysql_insert_id() <2>: insert. (line 206) * mysql_insert_id(): ansi-diff-transactions. (line 159) * mysql_install_db <1>: mysql-install-db. (line 6) * mysql_install_db <2>: programs-overview. (line 95) * mysql_install_db: mysql-install-db-problems. (line 6) * mysql_install_db, basedir option: mysql-install-db. (line 51) * mysql_install_db, datadir option: mysql-install-db. (line 61) * mysql_install_db, force option: mysql-install-db. (line 55) * mysql_install_db, ldata option: mysql-install-db. (line 61) * mysql_install_db, rpm option: mysql-install-db. (line 65) * mysql_install_db, skip-name-resolve option: mysql-install-db. (line 70) * mysql_install_db, srcdir option: mysql-install-db. (line 75) * mysql_install_db, user option: mysql-install-db. (line 82) * mysql_install_db, verbose option: mysql-install-db. (line 91) * mysql_install_db, windows option: mysql-install-db. (line 95) * mysql_kill(): mysql-kill. (line 6) * mysql_library_end(): mysql-library-end. (line 6) * mysql_library_init(): mysql-library-init. (line 6) * mysql_list_dbs(): mysql-list-dbs. (line 6) * mysql_list_fields(): mysql-list-fields. (line 6) * mysql_list_processes(): mysql-list-processes. (line 6) * mysql_list_tables(): mysql-list-tables. (line 6) * mysql_more_results(): mysql-more-results. (line 6) * mysql_next_result(): mysql-next-result. (line 6) * mysql_num_fields(): mysql-num-fields. (line 6) * mysql_num_rows(): mysql-num-rows. (line 6) * mysql_options(): mysql-options. (line 6) * mysql_ping(): mysql-ping. (line 6) * MYSQL_PS1 environment variable: environment-variables. (line 18) * MYSQL_PWD environment variable <1>: connecting. (line 231) * MYSQL_PWD environment variable <2>: programs-overview. (line 317) * MYSQL_PWD environment variable: environment-variables. (line 18) * mysql_query() <1>: c-api-problems. (line 12) * mysql_query(): mysql-query. (line 6) * mysql_real_connect(): mysql-real-connect. (line 6) * mysql_real_escape_string() <1>: mysql-real-escape-string. (line 6) * mysql_real_escape_string(): string-syntax. (line 142) * mysql_real_query(): mysql-real-query. (line 6) * mysql_refresh(): mysql-refresh. (line 6) * mysql_reload(): mysql-reload. (line 6) * MYSQL_RES C type: c-api-data-structures. (line 17) * mysql_rollback(): mysql-rollback. (line 6) * MYSQL_ROW C type: c-api-data-structures. (line 25) * mysql_row_seek(): mysql-row-seek. (line 6) * mysql_row_tell(): mysql-row-tell. (line 6) * mysql_secure_installation <1>: mysql-secure-installation. (line 6) * mysql_secure_installation: programs-overview. (line 103) * mysql_select_db(): mysql-select-db. (line 6) * mysql_server_end(): mysql-server-end. (line 6) * mysql_server_init(): mysql-server-init. (line 6) * mysql_set_character_set(): mysql-set-character-set. (line 6) * mysql_set_local_infile_default(): mysql-set-local-infile-default. (line 6) * mysql_set_server_option(): mysql-set-server-option. (line 6) * mysql_setpermission <1>: mysql-setpermission. (line 6) * mysql_setpermission: programs-overview. (line 239) * mysql_setpermission, help option: mysql-setpermission. (line 29) * mysql_setpermission, host option: mysql-setpermission. (line 33) * mysql_setpermission, password option: mysql-setpermission. (line 37) * mysql_setpermission, port option: mysql-setpermission. (line 47) * mysql_setpermission, socket option: mysql-setpermission. (line 51) * mysql_setpermission, user option: mysql-setpermission. (line 55) * mysql_shutdown(): mysql-shutdown. (line 6) * mysql_sqlstate(): mysql-sqlstate. (line 6) * mysql_ssl_set(): mysql-ssl-set. (line 6) * mysql_stat(): mysql-stat. (line 6) * MYSQL_STMT C type: c-api-prepared-statement-data-structures. (line 34) * mysql_stmt_affected_rows(): mysql-stmt-affected-rows. (line 6) * mysql_stmt_attr_get(): mysql-stmt-attr-get. (line 6) * mysql_stmt_attr_set(): mysql-stmt-attr-set. (line 6) * mysql_stmt_bind_param(): mysql-stmt-bind-param. (line 6) * mysql_stmt_bind_result(): mysql-stmt-bind-result. (line 6) * mysql_stmt_close(): mysql-stmt-close. (line 6) * mysql_stmt_data_seek(): mysql-stmt-data-seek. (line 6) * mysql_stmt_errno(): mysql-stmt-errno. (line 6) * mysql_stmt_error(): mysql-stmt-error. (line 6) * mysql_stmt_execute(): mysql-stmt-execute. (line 6) * mysql_stmt_fetch(): mysql-stmt-fetch. (line 6) * mysql_stmt_fetch_column(): mysql-stmt-fetch-column. (line 6) * mysql_stmt_field_count(): mysql-stmt-field-count. (line 6) * mysql_stmt_free_result(): mysql-stmt-free-result. (line 6) * mysql_stmt_init(): mysql-stmt-init. (line 6) * mysql_stmt_insert_id(): mysql-stmt-insert-id. (line 6) * mysql_stmt_num_rows(): mysql-stmt-num-rows. (line 6) * mysql_stmt_param_count(): mysql-stmt-param-count. (line 6) * mysql_stmt_param_metadata(): mysql-stmt-param-metadata. (line 6) * mysql_stmt_prepare(): mysql-stmt-prepare. (line 6) * mysql_stmt_reset(): mysql-stmt-reset. (line 6) * mysql_stmt_result_metadata: mysql-stmt-result-metadata. (line 6) * mysql_stmt_row_seek(): mysql-stmt-row-seek. (line 6) * mysql_stmt_row_tell(): mysql-stmt-row-tell. (line 6) * mysql_stmt_send_long_data(): mysql-stmt-send-long-data. (line 6) * mysql_stmt_sqlstate(): mysql-stmt-sqlstate. (line 6) * mysql_stmt_store_result(): mysql-stmt-store-result. (line 6) * mysql_store_result() <1>: c-api-problems. (line 12) * mysql_store_result(): mysql-store-result. (line 6) * MYSQL_TCP_PORT environment variable <1>: multiple-server-clients. (line 27) * MYSQL_TCP_PORT environment variable <2>: multiple-unix-servers. (line 68) * MYSQL_TCP_PORT environment variable <3>: programs-overview. (line 317) * MYSQL_TCP_PORT environment variable: environment-variables. (line 18) * mysql_thread_end(): mysql-thread-end. (line 6) * mysql_thread_id(): mysql-thread-id. (line 6) * mysql_thread_init(): mysql-thread-init. (line 6) * mysql_thread_safe(): mysql-thread-safe. (line 6) * MYSQL_TIME C type: c-api-prepared-statement-data-structures. (line 245) * mysql_tzinfo_to_sql <1>: mysql-tzinfo-to-sql. (line 6) * mysql_tzinfo_to_sql: programs-overview. (line 108) * MYSQL_UNIX_PORT environment variable <1>: multiple-server-clients. (line 27) * MYSQL_UNIX_PORT environment variable <2>: multiple-unix-servers. (line 68) * MYSQL_UNIX_PORT environment variable <3>: programs-overview. (line 317) * MYSQL_UNIX_PORT environment variable <4>: environment-variables. (line 18) * MYSQL_UNIX_PORT environment variable: mysql-install-db-problems. (line 84) * mysql_upgrade <1>: access-denied. (line 83) * mysql_upgrade <2>: mysql-upgrade. (line 6) * mysql_upgrade: programs-overview. (line 115) * mysql_upgrade, basedir option: mysql-upgrade. (line 120) * mysql_upgrade, datadir option: mysql-upgrade. (line 125) * mysql_upgrade, debug-check option: mysql-upgrade. (line 130) * mysql_upgrade, debug-info option: mysql-upgrade. (line 135) * mysql_upgrade, force option: mysql-upgrade. (line 140) * mysql_upgrade, help option: mysql-upgrade. (line 116) * mysql_upgrade, mysql_upgrade_info file: mysql-upgrade. (line 88) * mysql_upgrade, tmpdir option: mysql-upgrade. (line 147) * mysql_upgrade, user option: mysql-upgrade. (line 152) * mysql_upgrade, verbose option: mysql-upgrade. (line 157) * mysql_upgrade, write-binlog option: mysql-upgrade. (line 161) * mysql_upgrade_info file, mysql_upgrade: mysql-upgrade. (line 88) * mysql_use_result(): mysql-use-result. (line 6) * mysql_waitpid <1>: mysql-waitpid. (line 6) * mysql_waitpid: programs-overview. (line 244) * mysql_waitpid, help option: mysql-waitpid. (line 27) * mysql_waitpid, verbose option: mysql-waitpid. (line 31) * mysql_waitpid, version option: mysql-waitpid. (line 36) * mysql_warning_count(): mysql-warning-count. (line 6) * mysql_zap <1>: mysql-zap. (line 6) * mysql_zap: programs-overview. (line 249) * mysqlaccess <1>: mysqlaccess. (line 6) * mysqlaccess: programs-overview. (line 190) * mysqlaccess, brief option: mysqlaccess. (line 71) * mysqlaccess, commit option: mysqlaccess. (line 75) * mysqlaccess, copy option: mysqlaccess. (line 82) * mysqlaccess, db option: mysqlaccess. (line 86) * mysqlaccess, debug option: mysqlaccess. (line 90) * mysqlaccess, help option: mysqlaccess. (line 67) * mysqlaccess, host option: mysqlaccess. (line 94) * mysqlaccess, howto option: mysqlaccess. (line 98) * mysqlaccess, old_server option: mysqlaccess. (line 103) * mysqlaccess, password option: mysqlaccess. (line 108) * mysqlaccess, plan option: mysqlaccess. (line 117) * mysqlaccess, preview option: mysqlaccess. (line 121) * mysqlaccess, relnotes option: mysqlaccess. (line 126) * mysqlaccess, rhost option: mysqlaccess. (line 130) * mysqlaccess, rollback option: mysqlaccess. (line 134) * mysqlaccess, spassword option: mysqlaccess. (line 138) * mysqlaccess, superuser option: mysqlaccess. (line 148) * mysqlaccess, table option: mysqlaccess. (line 152) * mysqlaccess, user option: mysqlaccess. (line 156) * mysqlaccess, version option: mysqlaccess. (line 160) * mysqladmin <1>: kill. (line 6) * mysqladmin <2>: flush. (line 6) * mysqladmin <3>: show-variables. (line 9) * mysqladmin <4>: show-status. (line 9) * mysqladmin <5>: drop-database. (line 50) * mysqladmin <6>: create-database. (line 42) * mysqladmin <7>: mysqladmin. (line 6) * mysqladmin: programs-overview. (line 129) * mysqladmin command options: mysqladmin. (line 212) * mysqladmin option, mysqld_multi: mysqld-multi. (line 123) * mysqladmin, bind-address option: mysqladmin. (line 302) * mysqladmin, character-sets-dir option: mysqladmin. (line 313) * mysqladmin, compress option: mysqladmin. (line 318) * mysqladmin, count option: mysqladmin. (line 323) * mysqladmin, debug option: mysqladmin. (line 328) * mysqladmin, debug-check option: mysqladmin. (line 334) * mysqladmin, debug-info option: mysqladmin. (line 339) * mysqladmin, default-character-set option: mysqladmin. (line 344) * mysqladmin, force option: mysqladmin. (line 349) * mysqladmin, help option: mysqladmin. (line 298) * mysqladmin, host option: mysqladmin. (line 354) * mysqladmin, no-beep option: mysqladmin. (line 358) * mysqladmin, password option: mysqladmin. (line 364) * mysqladmin, pipe option: mysqladmin. (line 376) * mysqladmin, port option: mysqladmin. (line 381) * mysqladmin, protocol option: mysqladmin. (line 385) * mysqladmin, relative option: mysqladmin. (line 392) * mysqladmin, silent option: mysqladmin. (line 398) * mysqladmin, sleep option: mysqladmin. (line 402) * mysqladmin, socket option: mysqladmin. (line 409) * mysqladmin, SSL options: mysqladmin. (line 414) * mysqladmin, user option: mysqladmin. (line 420) * mysqladmin, verbose option: mysqladmin. (line 424) * mysqladmin, version option: mysqladmin. (line 428) * mysqladmin, vertical option: mysqladmin. (line 432) * mysqladmin, wait option: mysqladmin. (line 437) * mysqlbinlog <1>: mysqlbinlog. (line 11) * mysqlbinlog: programs-overview. (line 195) * mysqlbinlog, base64-output option: mysqlbinlog. (line 178) * mysqlbinlog, bind-address option: mysqlbinlog. (line 226) * mysqlbinlog, character-sets-dir option: mysqlbinlog. (line 237) * mysqlbinlog, database option: mysqlbinlog. (line 242) * mysqlbinlog, debug option: mysqlbinlog. (line 327) * mysqlbinlog, debug-check option: mysqlbinlog. (line 333) * mysqlbinlog, debug-info option: mysqlbinlog. (line 338) * mysqlbinlog, disable-log-bin option: mysqlbinlog. (line 343) * mysqlbinlog, force-read option: mysqlbinlog. (line 357) * mysqlbinlog, help option: mysqlbinlog. (line 174) * mysqlbinlog, hexdump option: mysqlbinlog. (line 364) * mysqlbinlog, host option: mysqlbinlog. (line 370) * mysqlbinlog, local-load option: mysqlbinlog. (line 374) * mysqlbinlog, offset option: mysqlbinlog. (line 384) * mysqlbinlog, password option: mysqlbinlog. (line 388) * mysqlbinlog, port option: mysqlbinlog. (line 400) * mysqlbinlog, position option: mysqlbinlog. (line 404) * mysqlbinlog, protocol option: mysqlbinlog. (line 409) * mysqlbinlog, read-from-remote-server option: mysqlbinlog. (line 416) * mysqlbinlog, result-file option: mysqlbinlog. (line 427) * mysqlbinlog, server-id option: mysqlbinlog. (line 431) * mysqlbinlog, server-id-bits option: mysqlbinlog. (line 436) * mysqlbinlog, set-charset option: mysqlbinlog. (line 450) * mysqlbinlog, short-form option: mysqlbinlog. (line 456) * mysqlbinlog, socket option: mysqlbinlog. (line 462) * mysqlbinlog, start-datetime option: mysqlbinlog. (line 467) * mysqlbinlog, start-position option: mysqlbinlog. (line 481) * mysqlbinlog, stop-datetime option: mysqlbinlog. (line 490) * mysqlbinlog, stop-position option: mysqlbinlog. (line 500) * mysqlbinlog, to-last-log option: mysqlbinlog. (line 509) * mysqlbinlog, user option: mysqlbinlog. (line 517) * mysqlbinlog, verbose option: mysqlbinlog. (line 521) * mysqlbinlog, version option: mysqlbinlog. (line 532) * mysqlbug: mysqlbug. (line 6) * mysqlcheck <1>: mysqlcheck. (line 6) * mysqlcheck: programs-overview. (line 137) * mysqlcheck, all-databases option: mysqlcheck. (line 201) * mysqlcheck, all-in-1 option: mysqlcheck. (line 207) * mysqlcheck, analyze option: mysqlcheck. (line 213) * mysqlcheck, auto-repair option: mysqlcheck. (line 217) * mysqlcheck, bind-address option: mysqlcheck. (line 222) * mysqlcheck, character-sets-dir option: mysqlcheck. (line 233) * mysqlcheck, check option: mysqlcheck. (line 238) * mysqlcheck, check-only-changed option: mysqlcheck. (line 242) * mysqlcheck, check-upgrade option: mysqlcheck. (line 247) * mysqlcheck, compress option: mysqlcheck. (line 255) * mysqlcheck, databases option: mysqlcheck. (line 260) * mysqlcheck, debug option: mysqlcheck. (line 268) * mysqlcheck, debug-check option: mysqlcheck. (line 273) * mysqlcheck, debug-info option: mysqlcheck. (line 278) * mysqlcheck, default-character-set option: mysqlcheck. (line 283) * mysqlcheck, extended option: mysqlcheck. (line 288) * mysqlcheck, fast option: mysqlcheck. (line 297) * mysqlcheck, fix-db-names option: mysqlcheck. (line 301) * mysqlcheck, fix-table-names option: mysqlcheck. (line 307) * mysqlcheck, force option: mysqlcheck. (line 313) * mysqlcheck, help option: mysqlcheck. (line 197) * mysqlcheck, host option: mysqlcheck. (line 317) * mysqlcheck, medium-check option: mysqlcheck. (line 321) * mysqlcheck, optimize option: mysqlcheck. (line 327) * mysqlcheck, password option: mysqlcheck. (line 331) * mysqlcheck, pipe option: mysqlcheck. (line 343) * mysqlcheck, port option: mysqlcheck. (line 348) * mysqlcheck, protocol option: mysqlcheck. (line 352) * mysqlcheck, quick option: mysqlcheck. (line 359) * mysqlcheck, repair option: mysqlcheck. (line 368) * mysqlcheck, silent option: mysqlcheck. (line 373) * mysqlcheck, socket option: mysqlcheck. (line 377) * mysqlcheck, SSL options: mysqlcheck. (line 382) * mysqlcheck, tables option: mysqlcheck. (line 388) * mysqlcheck, use-frm option: mysqlcheck. (line 393) * mysqlcheck, user option: mysqlcheck. (line 399) * mysqlcheck, verbose option: mysqlcheck. (line 403) * mysqlcheck, version option: mysqlcheck. (line 408) * mysqlcheck, write-binlog option: mysqlcheck. (line 412) * mysqlclient library: connectors-apis. (line 24) * mysqld: programs-overview. (line 38) * mysqld (MySQL Cluster): mysql-cluster-programs. (line 32) * mysqld library: connectors-apis. (line 24) * mysqld option, mysqld_multi: mysqld-multi. (line 128) * mysqld option, mysqld_safe: mysqld-safe. (line 171) * mysqld options: server-parameters. (line 11) * mysqld options and variables, MySQL Cluster: mysql-cluster-options-variables. (line 13) * mysqld server, buffer sizes: server-parameters. (line 6) * mysqld, abort-slave-event-count option: replication-options-slave. (line 134) * mysqld, allow-suspicious-udfs option <1>: privileges-options. (line 41) * mysqld, allow-suspicious-udfs option: server-options. (line 83) * mysqld, ansi option: server-options. (line 102) * mysqld, as MySQL Cluster process <1>: mysql-cluster-programs-mysqld. (line 6) * mysqld, as MySQL Cluster process: mysql-cluster-program-options-mysqld. (line 6) * mysqld, basedir option: server-options. (line 114) * mysqld, big-tables option: server-options. (line 135) * mysqld, bind-address option: server-options. (line 158) * mysqld, binlog-do-db option: replication-options-binary-log. (line 132) * mysqld, binlog-format option: server-options. (line 181) * mysqld, binlog-ignore-db option: replication-options-binary-log. (line 257) * mysqld, binlog-row-event-max-size option: replication-options-binary-log. (line 20) * mysqld, bootstrap option: server-options. (line 254) * mysqld, character-set-client-handshake option: server-options. (line 289) * mysqld, character-set-filesystem option: server-options. (line 306) * mysqld, character-set-server option: server-options. (line 328) * mysqld, character-sets-dir option: server-options. (line 269) * mysqld, chroot option: server-options. (line 350) * mysqld, collation-server option: server-options. (line 370) * mysqld, command options: server-options. (line 6) * mysqld, console option: server-options. (line 390) * mysqld, core-file option: server-options. (line 402) * mysqld, datadir option: server-options. (line 431) * mysqld, debug option: server-options. (line 451) * mysqld, debug-sync-timeout option: server-options. (line 484) * mysqld, default-character-set option: server-options. (line 512) * mysqld, default-collation option: server-options. (line 531) * mysqld, default-storage-engine option: server-options. (line 548) * mysqld, default-table-type option: server-options. (line 562) * mysqld, default-time-zone option: server-options. (line 579) * mysqld, delay-key-write option <1>: myisam-start. (line 42) * mysqld, delay-key-write option: server-options. (line 595) * mysqld, des-key-file option: server-options. (line 629) * mysqld, disconnect-slave-event-count option: replication-options-slave. (line 161) * mysqld, enable-named-pipe option: server-options. (line 639) * mysqld, enable-pstack option: server-options. (line 657) * mysqld, event-scheduler option: server-options. (line 699) * mysqld, exit-info option: server-options. (line 726) * mysqld, external-locking option: server-options. (line 743) * mysqld, flush option: server-options. (line 768) * mysqld, gdb option: server-options. (line 788) * mysqld, general-log option: server-options. (line 805) * mysqld, help option: server-options. (line 72) * mysqld, ignore-builtin-innodb option: innodb-parameters. (line 134) * mysqld, init-file option: server-options. (line 828) * mysqld, innodb option: innodb-parameters. (line 172) * mysqld, innodb-status-file option: innodb-parameters. (line 186) * mysqld, install option: server-options. (line 856) * mysqld, install-manual option: server-options. (line 867) * mysqld, language option: server-options. (line 879) * mysqld, large-pages option: server-options. (line 906) * mysqld, local-infile option: privileges-options. (line 50) * mysqld, log option: server-options. (line 937) * mysqld, log-bin option: replication-options-binary-log. (line 48) * mysqld, log-bin-index option: replication-options-binary-log. (line 78) * mysqld, log-bin-trust-function-creators option: replication-options-binary-log. (line 95) * mysqld, log-error option: server-options. (line 973) * mysqld, log-isam option: server-options. (line 995) * mysqld, log-long-format option: server-options. (line 1010) * mysqld, log-output option: server-options. (line 1028) * mysqld, log-queries-not-using-indexes option: server-options. (line 1072) * mysqld, log-short-format option: server-options. (line 1095) * mysqld, log-slave-updates option: replication-options-slave. (line 176) * mysqld, log-slow-admin-statements option: server-options. (line 1111) * mysqld, log-slow-queries option: server-options. (line 1127) * mysqld, log-slow-slave-statements option: replication-options-slave. (line 227) * mysqld, log-tc option: server-options. (line 1164) * mysqld, log-tc-size option: server-options. (line 1183) * mysqld, log-warnings option <1>: replication-options-slave. (line 246) * mysqld, log-warnings option: server-options. (line 1207) * mysqld, low-priority-updates option: server-options. (line 1248) * mysqld, master-connect-retry option: replication-options-slave. (line 281) * mysqld, master-host option: replication-options-slave. (line 307) * mysqld, master-info-file option: replication-options-slave. (line 327) * mysqld, master-password option: replication-options-slave. (line 345) * mysqld, master-port option: replication-options-slave. (line 366) * mysqld, master-retry-count option: replication-options-slave. (line 387) * mysqld, master-ssl option: replication-options-slave. (line 417) * mysqld, master-ssl-ca option: replication-options-slave. (line 417) * mysqld, master-ssl-capath option: replication-options-slave. (line 417) * mysqld, master-ssl-cert option: replication-options-slave. (line 417) * mysqld, master-ssl-cipher option: replication-options-slave. (line 417) * mysqld, master-ssl-key option: replication-options-slave. (line 417) * mysqld, master-user option: replication-options-slave. (line 432) * mysqld, max-binlog-dump-events option: replication-options-binary-log. (line 327) * mysqld, max-relay-log-size option: replication-options-slave. (line 455) * mysqld, memlock option: server-options. (line 1306) * mysqld, min-examined-row-limit option: server-options. (line 1275) * mysqld, myisam-block-size option: server-options. (line 1350) * mysqld, myisam-recover option <1>: myisam-start. (line 38) * mysqld, myisam-recover option: server-options. (line 1365) * mysqld, MySQL server <1>: mysqld-server. (line 19) * mysqld, MySQL server: mysqld. (line 6) * mysqld, ndb-batch-size option: mysql-cluster-program-options-mysqld. (line 23) * mysqld, ndb-blob-read-batch-bytes option: mysql-cluster-program-options-mysqld. (line 103) * mysqld, ndb-blob-write-batch-bytes option: mysql-cluster-program-options-mysqld. (line 144) * mysqld, ndb-cluster-connection-pool option: mysql-cluster-program-options-mysqld. (line 43) * mysqld, ndb-connectstring option: mysql-cluster-program-options-mysqld. (line 186) * mysqld, ndb-log-apply-status: mysql-cluster-program-options-mysqld. (line 224) * mysqld, ndb-nodeid: mysql-cluster-program-options-mysqld. (line 265) * mysqld, ndbcluster option: mysql-cluster-program-options-mysqld. (line 202) * mysqld, old-alter-table option: server-options. (line 1418) * mysqld, old-passwords option <1>: privileges-options. (line 56) * mysqld, old-passwords option: server-options. (line 1444) * mysqld, old-style-user-limits option: server-options. (line 1466) * mysqld, one-thread option: server-options. (line 1483) * mysqld, open-files-limit option: server-options. (line 1498) * mysqld, partition option: server-options. (line 1529) * mysqld, pid-file option: server-options. (line 1550) * mysqld, plugin option prefix: server-options. (line 1573) * mysqld, plugin-load option: server-options. (line 1598) * mysqld, port option: server-options. (line 1650) * mysqld, port-open-timeout option: server-options. (line 1672) * mysqld, read-only option: replication-options-slave. (line 461) * mysqld, relay-log option: replication-options-slave. (line 469) * mysqld, relay-log-index option: replication-options-slave. (line 514) * mysqld, relay-log-info-file option: replication-options-slave. (line 551) * mysqld, relay-log-purge option: replication-options-slave. (line 571) * mysqld, relay-log-space-limit option: replication-options-slave. (line 578) * mysqld, remove option: server-options. (line 1692) * mysqld, replicate-do-db option: replication-options-slave. (line 599) * mysqld, replicate-do-table option: replication-options-slave. (line 785) * mysqld, replicate-ignore-db option: replication-options-slave. (line 715) * mysqld, replicate-ignore-table option: replication-options-slave. (line 807) * mysqld, replicate-rewrite-db option: replication-options-slave. (line 830) * mysqld, replicate-same-server-id option: replication-options-slave. (line 859) * mysqld, replicate-wild-do-table option: replication-options-slave. (line 883) * mysqld, replicate-wild-ignore-table option: replication-options-slave. (line 930) * mysqld, report-host option: replication-options-slave. (line 956) * mysqld, report-password option: replication-options-slave. (line 982) * mysqld, report-port option: replication-options-slave. (line 1008) * mysqld, report-user option: replication-options-slave. (line 1031) * mysqld, role in MySQL Cluster: mysql-cluster-basics. (line 6) * mysqld, safe-mode option: server-options. (line 1702) * mysqld, safe-show-database option: server-options. (line 1712) * mysqld, safe-user-create option <1>: privileges-options. (line 62) * mysqld, safe-user-create option: server-options. (line 1733) * mysqld, secure-auth option <1>: privileges-options. (line 77) * mysqld, secure-auth option: server-options. (line 1758) * mysqld, secure-file-priv option <1>: privileges-options. (line 86) * mysqld, secure-file-priv option: server-options. (line 1778) * mysqld, server-id option: replication-options. (line 21) * mysqld, server-id-bits option: mysql-cluster-program-options-mysqld. (line 315) * mysqld, shared-memory option: server-options. (line 1802) * mysqld, shared-memory-base-name option: server-options. (line 1807) * mysqld, show-slave-auth-info option: replication-options-slave. (line 1057) * mysqld, skip-concurrent-insert option: server-options. (line 1813) * mysqld, skip-event-scheduler option: server-options. (line 1828) * mysqld, skip-external-locking option: server-options. (line 1819) * mysqld, skip-grant-tables option <1>: privileges-options. (line 95) * mysqld, skip-grant-tables option: server-options. (line 1841) * mysqld, skip-host-cache option: server-options. (line 1860) * mysqld, skip-innodb option <1>: innodb-parameters. (line 197) * mysqld, skip-innodb option: server-options. (line 1866) * mysqld, skip-merge option: privileges-options. (line 114) * mysqld, skip-name-resolve option <1>: privileges-options. (line 119) * mysqld, skip-name-resolve option: server-options. (line 1873) * mysqld, skip-ndbcluster option: mysql-cluster-program-options-mysqld. (line 363) * mysqld, skip-networking option <1>: privileges-options. (line 124) * mysqld, skip-networking option: server-options. (line 1880) * mysqld, skip-partition option: server-options. (line 1888) * mysqld, skip-safemalloc option: server-options. (line 1940) * mysqld, skip-show-database option <1>: privileges-options. (line 129) * mysqld, skip-show-database option: server-options. (line 1953) * mysqld, skip-slave-start option: replication-options-slave. (line 1074) * mysqld, skip-stack-trace option: server-options. (line 1974) * mysqld, skip-symbolic-links option: server-options. (line 1917) * mysqld, skip-thread-priority option: server-options. (line 1987) * mysqld, slave-load-tmpdir option: replication-options-slave. (line 1111) * mysqld, slave-net-timeout option: replication-options-slave. (line 1133) * mysqld, slave-skip-errors option: replication-options-slave. (line 1161) * mysqld, slave_compressed_protocol option: replication-options-slave. (line 1090) * mysqld, slow-query-log option: server-options. (line 2008) * mysqld, socket option: server-options. (line 2031) * mysqld, sporadic-binlog-dump-fail option: replication-options-binary-log. (line 342) * mysqld, sql-mode option: server-options. (line 2058) * mysqld, SSL options <1>: privileges-options. (line 139) * mysqld, SSL options: server-options. (line 1900) * mysqld, standalone option: server-options. (line 1906) * mysqld, starting: changing-mysql-user. (line 6) * mysqld, symbolic-links option: server-options. (line 1917) * mysqld, sysdate-is-now option: server-options. (line 2100) * mysqld, tc-heuristic-recover option: server-options. (line 2123) * mysqld, temp-pool option: server-options. (line 2139) * mysqld, tmpdir option: server-options. (line 2184) * mysqld, transaction-isolation option: server-options. (line 2159) * mysqld, user option: server-options. (line 2218) * mysqld, verbose option: server-options. (line 2253) * mysqld, version option: server-options. (line 2257) * mysqld-safe-compatible option, mysqlmanager: instance-manager-command-options. (line 153) * mysqld-version option, mysqld_safe: mysqld-safe. (line 180) * mysqld_multi <1>: mysqld-multi. (line 6) * mysqld_multi: programs-overview. (line 58) * mysqld_multi, config-file option: mysqld-multi. (line 100) * mysqld_multi, defaults-extra-file option: mysqld-multi. (line 68) * mysqld_multi, defaults-file option: mysqld-multi. (line 66) * mysqld_multi, example option: mysqld-multi. (line 114) * mysqld_multi, help option: mysqld-multi. (line 96) * mysqld_multi, log option: mysqld-multi. (line 118) * mysqld_multi, mysqladmin option: mysqld-multi. (line 123) * mysqld_multi, mysqld option: mysqld-multi. (line 128) * mysqld_multi, no-defaults option: mysqld-multi. (line 64) * mysqld_multi, no-log option: mysqld-multi. (line 144) * mysqld_multi, password option: mysqld-multi. (line 149) * mysqld_multi, silent option: mysqld-multi. (line 155) * mysqld_multi, tcp-ip option: mysqld-multi. (line 159) * mysqld_multi, user option: mysqld-multi. (line 167) * mysqld_multi, verbose option: mysqld-multi. (line 172) * mysqld_multi, version option: mysqld-multi. (line 176) * mysqld_safe <1>: mysqld-safe. (line 6) * mysqld_safe: programs-overview. (line 45) * mysqld_safe, autoclose option: mysqld-safe. (line 123) * mysqld_safe, basedir option: mysqld-safe. (line 135) * mysqld_safe, core-file-size option: mysqld-safe. (line 139) * mysqld_safe, datadir option: mysqld-safe. (line 144) * mysqld_safe, defaults-extra-file option: mysqld-safe. (line 148) * mysqld_safe, defaults-file option: mysqld-safe. (line 155) * mysqld_safe, help option: mysqld-safe. (line 119) * mysqld_safe, ledir option: mysqld-safe. (line 161) * mysqld_safe, log-error option: mysqld-safe. (line 167) * mysqld_safe, mysqld option: mysqld-safe. (line 171) * mysqld_safe, mysqld-version option: mysqld-safe. (line 180) * mysqld_safe, nice option: mysqld-safe. (line 191) * mysqld_safe, no-defaults option: mysqld-safe. (line 196) * mysqld_safe, open-files-limit option: mysqld-safe. (line 201) * mysqld_safe, pid-file option: mysqld-safe. (line 208) * mysqld_safe, port option: mysqld-safe. (line 212) * mysqld_safe, skip-kill-mysqld option: mysqld-safe. (line 218) * mysqld_safe, skip-syslog option: mysqld-safe. (line 228) * mysqld_safe, socket option: mysqld-safe. (line 223) * mysqld_safe, syslog option: mysqld-safe. (line 228) * mysqld_safe, syslog-tag option: mysqld-safe. (line 235) * mysqld_safe, timezone option: mysqld-safe. (line 244) * mysqld_safe, user option: mysqld-safe. (line 250) * mysqldump <1>: mysqldump. (line 6) * mysqldump <2>: programs-overview. (line 142) * mysqldump: copying-databases. (line 45) * mysqldump, add-drop-database option: mysqldump. (line 331) * mysqldump, add-drop-table option: mysqldump. (line 340) * mysqldump, add-drop-trigger option: mysqldump. (line 345) * mysqldump, add-locks option: mysqldump. (line 357) * mysqldump, all-databases option: mysqldump. (line 364) * mysqldump, all-tablespaces option: mysqldump. (line 370) * mysqldump, allow-keywords option: mysqldump. (line 380) * mysqldump, bind-address option: mysqldump. (line 385) * mysqldump, character-sets-dir option: mysqldump. (line 396) * mysqldump, comments option: mysqldump. (line 401) * mysqldump, compact option: mysqldump. (line 408) * mysqldump, compatible option: mysqldump. (line 423) * mysqldump, complete-insert option: mysqldump. (line 443) * mysqldump, compress option: mysqldump. (line 448) * mysqldump, create-options option: mysqldump. (line 453) * mysqldump, databases option: mysqldump. (line 458) * mysqldump, debug option: mysqldump. (line 467) * mysqldump, debug-check option: mysqldump. (line 473) * mysqldump, debug-info option: mysqldump. (line 478) * mysqldump, default-character-set option: mysqldump. (line 483) * mysqldump, delayed-insert option: mysqldump. (line 494) * mysqldump, delete-master-logs option: mysqldump. (line 499) * mysqldump, disable-keys option: mysqldump. (line 506) * mysqldump, dump-date option: mysqldump. (line 515) * mysqldump, events option: mysqldump. (line 529) * mysqldump, extended-insert option: mysqldump. (line 534) * mysqldump, fields-enclosed-by option <1>: mysqlimport. (line 186) * mysqldump, fields-enclosed-by option: mysqldump. (line 542) * mysqldump, fields-escaped-by option <1>: mysqlimport. (line 190) * mysqldump, fields-escaped-by option: mysqldump. (line 546) * mysqldump, fields-optionally-enclosed-by option <1>: mysqlimport. (line 188) * mysqldump, fields-optionally-enclosed-by option: mysqldump. (line 544) * mysqldump, fields-terminated-by option <1>: mysqlimport. (line 184) * mysqldump, fields-terminated-by option: mysqldump. (line 540) * mysqldump, first-slave option: mysqldump. (line 552) * mysqldump, flush-logs option: mysqldump. (line 557) * mysqldump, flush-privileges option: mysqldump. (line 569) * mysqldump, force option: mysqldump. (line 577) * mysqldump, help option: mysqldump. (line 327) * mysqldump, hex-blob option: mysqldump. (line 595) * mysqldump, host option: mysqldump. (line 590) * mysqldump, ignore-table option: mysqldump. (line 602) * mysqldump, insert-ignore option: mysqldump. (line 609) * mysqldump, lines-terminated-by option <1>: mysqlimport. (line 214) * mysqldump, lines-terminated-by option: mysqldump. (line 614) * mysqldump, lock-all-tables option: mysqldump. (line 620) * mysqldump, lock-tables option: mysqldump. (line 627) * mysqldump, log-error option: mysqldump. (line 641) * mysqldump, master-data option: mysqldump. (line 646) * mysqldump, no-autocommit option: mysqldump. (line 713) * mysqldump, no-create-db option: mysqldump. (line 719) * mysqldump, no-create-info option: mysqldump. (line 725) * mysqldump, no-data option: mysqldump. (line 737) * mysqldump, no-set-names option: mysqldump. (line 745) * mysqldump, no-tablespaces option: mysqldump. (line 749) * mysqldump, opt option: mysqldump. (line 758) * mysqldump, order-by-primary option: mysqldump. (line 772) * mysqldump, password option: mysqldump. (line 779) * mysqldump, pipe option: mysqldump. (line 791) * mysqldump, port option: mysqldump. (line 796) * mysqldump, problems <1>: view-restrictions. (line 111) * mysqldump, problems: mysqldump. (line 1150) * mysqldump, protocol option: mysqldump. (line 800) * mysqldump, quick option: mysqldump. (line 807) * mysqldump, quote-names option: mysqldump. (line 814) * mysqldump, replace option: mysqldump. (line 823) * mysqldump, result-file option: mysqldump. (line 829) * mysqldump, routines option: mysqldump. (line 837) * mysqldump, set-charset option: mysqldump. (line 864) * mysqldump, single-transaction option: mysqldump. (line 870) * mysqldump, skip-comments option: mysqldump. (line 908) * mysqldump, skip-opt option: mysqldump. (line 912) * mysqldump, socket option: mysqldump. (line 916) * mysqldump, SSL options: mysqldump. (line 921) * mysqldump, tab option: mysqldump. (line 927) * mysqldump, tables option: mysqldump. (line 956) * mysqldump, triggers option: mysqldump. (line 962) * mysqldump, tz-utc option: mysqldump. (line 967) * mysqldump, user option: mysqldump. (line 981) * mysqldump, using for backups: using-mysqldump. (line 14) * mysqldump, verbose option: mysqldump. (line 985) * mysqldump, version option: mysqldump. (line 989) * mysqldump, views <1>: view-restrictions. (line 111) * mysqldump, views: mysqldump. (line 1150) * mysqldump, where option: mysqldump. (line 993) * mysqldump, workarounds <1>: view-restrictions. (line 111) * mysqldump, workarounds: mysqldump. (line 1150) * mysqldump, xml option: mysqldump. (line 1005) * mysqldumpslow <1>: mysqldumpslow. (line 6) * mysqldumpslow: programs-overview. (line 201) * mysqldumpslow, debug option: mysqldumpslow. (line 53) * mysqldumpslow, help option: mysqldumpslow. (line 45) * mysqldumpslow, verbose option: mysqldumpslow. (line 103) * mysqlhotcopy <1>: mysqlhotcopy. (line 6) * mysqlhotcopy: programs-overview. (line 206) * mysqlhotcopy, addtodest option: mysqlhotcopy. (line 83) * mysqlhotcopy, allowold option: mysqlhotcopy. (line 88) * mysqlhotcopy, checkpoint option: mysqlhotcopy. (line 93) * mysqlhotcopy, chroot option: mysqlhotcopy. (line 98) * mysqlhotcopy, debug option: mysqlhotcopy. (line 104) * mysqlhotcopy, dryrun option: mysqlhotcopy. (line 108) * mysqlhotcopy, flushlog option: mysqlhotcopy. (line 112) * mysqlhotcopy, help option: mysqlhotcopy. (line 79) * mysqlhotcopy, host option: mysqlhotcopy. (line 116) * mysqlhotcopy, keepold option: mysqlhotcopy. (line 122) * mysqlhotcopy, method option: mysqlhotcopy. (line 126) * mysqlhotcopy, noindices option: mysqlhotcopy. (line 130) * mysqlhotcopy, password option: mysqlhotcopy. (line 137) * mysqlhotcopy, port option: mysqlhotcopy. (line 147) * mysqlhotcopy, quiet option: mysqlhotcopy. (line 151) * mysqlhotcopy, record_log_pos option: mysqlhotcopy. (line 155) * mysqlhotcopy, regexp option: mysqlhotcopy. (line 160) * mysqlhotcopy, resetmaster option: mysqlhotcopy. (line 165) * mysqlhotcopy, resetslave option: mysqlhotcopy. (line 169) * mysqlhotcopy, socket option: mysqlhotcopy. (line 173) * mysqlhotcopy, suffix option: mysqlhotcopy. (line 177) * mysqlhotcopy, tmpdir option: mysqlhotcopy. (line 181) * mysqlhotcopy, user option: mysqlhotcopy. (line 185) * mysqlimport <1>: load-data. (line 67) * mysqlimport <2>: mysqlimport. (line 6) * mysqlimport <3>: programs-overview. (line 147) * mysqlimport: copying-databases. (line 45) * mysqlimport, bind-address option: mysqlimport. (line 133) * mysqlimport, character-sets-dir option: mysqlimport. (line 144) * mysqlimport, columns option: mysqlimport. (line 149) * mysqlimport, compress option: mysqlimport. (line 155) * mysqlimport, debug option: mysqlimport. (line 160) * mysqlimport, debug-check option: mysqlimport. (line 165) * mysqlimport, debug-info option: mysqlimport. (line 170) * mysqlimport, default-character-set option: mysqlimport. (line 175) * mysqlimport, delete option: mysqlimport. (line 180) * mysqlimport, force option: mysqlimport. (line 195) * mysqlimport, help option: mysqlimport. (line 129) * mysqlimport, host option: mysqlimport. (line 201) * mysqlimport, ignore option: mysqlimport. (line 206) * mysqlimport, ignore-lines option: mysqlimport. (line 210) * mysqlimport, local option: mysqlimport. (line 223) * mysqlimport, lock-tables option: mysqlimport. (line 227) * mysqlimport, low-priority option: mysqlimport. (line 232) * mysqlimport, password option: mysqlimport. (line 238) * mysqlimport, pipe option: mysqlimport. (line 250) * mysqlimport, port option: mysqlimport. (line 255) * mysqlimport, protocol option: mysqlimport. (line 259) * mysqlimport, replace option: mysqlimport. (line 266) * mysqlimport, silent option: mysqlimport. (line 276) * mysqlimport, socket option: mysqlimport. (line 280) * mysqlimport, SSL options: mysqlimport. (line 285) * mysqlimport, use-threads option: mysqlimport. (line 295) * mysqlimport, user option: mysqlimport. (line 291) * mysqlimport, verbose option: mysqlimport. (line 300) * mysqlimport, version option: mysqlimport. (line 304) * mysqlmanager <1>: instance-manager. (line 16) * mysqlmanager: programs-overview. (line 211) * mysqlmanager, add-user option: instance-manager-command-options. (line 27) * mysqlmanager, angel-pid-file option: instance-manager-command-options. (line 32) * mysqlmanager, bind-address option: instance-manager-command-options. (line 46) * mysqlmanager, check-password-file option: instance-manager-command-options. (line 50) * mysqlmanager, clean-password-file option: instance-manager-command-options. (line 55) * mysqlmanager, debug option: instance-manager-command-options. (line 60) * mysqlmanager, default-mysqld-path option: instance-manager-command-options. (line 65) * mysqlmanager, defaults-file option: instance-manager-command-options. (line 74) * mysqlmanager, drop-user option: instance-manager-command-options. (line 86) * mysqlmanager, edit-user option: instance-manager-command-options. (line 91) * mysqlmanager, help option: instance-manager-command-options. (line 23) * mysqlmanager, install option: instance-manager-command-options. (line 97) * mysqlmanager, list-users option: instance-manager-command-options. (line 102) * mysqlmanager, log option: instance-manager-command-options. (line 107) * mysqlmanager, monitoring-interval option: instance-manager-command-options. (line 125) * mysqlmanager, mysqld-safe-compatible option: instance-manager-command-options. (line 153) * mysqlmanager, password option: instance-manager-command-options. (line 159) * mysqlmanager, password-file option: instance-manager-command-options. (line 167) * mysqlmanager, pid-file option: instance-manager-command-options. (line 175) * mysqlmanager, port option: instance-manager-command-options. (line 182) * mysqlmanager, print-defaults option: instance-manager-command-options. (line 187) * mysqlmanager, print-password-line option: instance-manager-command-options. (line 192) * mysqlmanager, remove option: instance-manager-command-options. (line 200) * mysqlmanager, run-as-service option: instance-manager-command-options. (line 206) * mysqlmanager, socket option: instance-manager-command-options. (line 212) * mysqlmanager, standalone option: instance-manager-command-options. (line 218) * mysqlmanager, user option: instance-manager-command-options. (line 224) * mysqlmanager, username option: instance-manager-command-options. (line 235) * mysqlmanager, version option: instance-manager-command-options. (line 240) * mysqlmanager, wait-timeout option: instance-manager-command-options. (line 244) * mysqlshow <1>: mysqlshow. (line 6) * mysqlshow: programs-overview. (line 152) * mysqlshow, bind-address option: mysqlshow. (line 114) * mysqlshow, character-sets-dir option: mysqlshow. (line 125) * mysqlshow, compress option: mysqlshow. (line 130) * mysqlshow, count option: mysqlshow. (line 135) * mysqlshow, debug option: mysqlshow. (line 140) * mysqlshow, debug-check option: mysqlshow. (line 145) * mysqlshow, debug-info option: mysqlshow. (line 150) * mysqlshow, default-character-set option: mysqlshow. (line 155) * mysqlshow, help option: mysqlshow. (line 110) * mysqlshow, host option: mysqlshow. (line 160) * mysqlshow, keys option: mysqlshow. (line 164) * mysqlshow, password option: mysqlshow. (line 168) * mysqlshow, pipe option: mysqlshow. (line 180) * mysqlshow, port option: mysqlshow. (line 185) * mysqlshow, protocol option: mysqlshow. (line 189) * mysqlshow, show-table-type option: mysqlshow. (line 196) * mysqlshow, socket option: mysqlshow. (line 201) * mysqlshow, SSL options: mysqlshow. (line 206) * mysqlshow, status option: mysqlshow. (line 212) * mysqlshow, user option: mysqlshow. (line 216) * mysqlshow, verbose option: mysqlshow. (line 220) * mysqlshow, version option: mysqlshow. (line 226) * mysqlslap <1>: mysqlslap. (line 6) * mysqlslap: programs-overview. (line 157) * mysqlslap, auto-generate-sql option: mysqlslap. (line 215) * mysqlslap, auto-generate-sql-add-autoincrement option: mysqlslap. (line 220) * mysqlslap, auto-generate-sql-execute-number option: mysqlslap. (line 225) * mysqlslap, auto-generate-sql-guid-primary option: mysqlslap. (line 230) * mysqlslap, auto-generate-sql-load-type option: mysqlslap. (line 235) * mysqlslap, auto-generate-sql-secondary-indexes option: mysqlslap. (line 243) * mysqlslap, auto-generate-sql-unique-query-number option: mysqlslap. (line 249) * mysqlslap, auto-generate-sql-unique-write-number option: mysqlslap. (line 257) * mysqlslap, auto-generate-sql-write-number option: mysqlslap. (line 263) * mysqlslap, commit option: mysqlslap. (line 268) * mysqlslap, compress option: mysqlslap. (line 273) * mysqlslap, concurrency option: mysqlslap. (line 278) * mysqlslap, create option: mysqlslap. (line 283) * mysqlslap, create-and-drop-schema option: mysqlslap. (line 288) * mysqlslap, create-schema option: mysqlslap. (line 294) * mysqlslap, csv option: mysqlslap. (line 306) * mysqlslap, debug option: mysqlslap. (line 312) * mysqlslap, debug-check option: mysqlslap. (line 318) * mysqlslap, debug-info option: mysqlslap. (line 323) * mysqlslap, delimiter option: mysqlslap. (line 328) * mysqlslap, detach option: mysqlslap. (line 333) * mysqlslap, engine option: mysqlslap. (line 339) * mysqlslap, help option: mysqlslap. (line 211) * mysqlslap, host option: mysqlslap. (line 343) * mysqlslap, iterations option: mysqlslap. (line 347) * mysqlslap, lock-directory option: mysqlslap. (line 351) * mysqlslap, number-char-cols option: mysqlslap. (line 356) * mysqlslap, number-int-cols option: mysqlslap. (line 361) * mysqlslap, number-of-queries option: mysqlslap. (line 366) * mysqlslap, only-print option: mysqlslap. (line 379) * mysqlslap, password option: mysqlslap. (line 385) * mysqlslap, pipe option: mysqlslap. (line 397) * mysqlslap, port option: mysqlslap. (line 402) * mysqlslap, post-query option: mysqlslap. (line 406) * mysqlslap, post-system option: mysqlslap. (line 418) * mysqlslap, pre-query option: mysqlslap. (line 424) * mysqlslap, pre-system option: mysqlslap. (line 430) * mysqlslap, preserve-schema option: mysqlslap. (line 436) * mysqlslap, protocol option: mysqlslap. (line 443) * mysqlslap, query option: mysqlslap. (line 450) * mysqlslap, shared-memory-base-name option: mysqlslap. (line 412) * mysqlslap, silent option: mysqlslap. (line 455) * mysqlslap, slave option: mysqlslap. (line 459) * mysqlslap, socket option: mysqlslap. (line 466) * mysqlslap, SSL options: mysqlslap. (line 471) * mysqlslap, use-threads option: mysqlslap. (line 477) * mysqlslap, user option: mysqlslap. (line 484) * mysqlslap, verbose option: mysqlslap. (line 488) * mysqlslap, version option: mysqlslap. (line 494) * mysqltest, MySQL Test Suite: mysql-test-suite. (line 6) * NAME_CONST() <1>: stored-programs-logging. (line 345) * NAME_CONST(): miscellaneous-functions. (line 181) * name_file option, comp_err: comp-err. (line 53) * named pipes <1>: windows-testing. (line 6) * named pipes: windows-select-server. (line 45) * named-commands option, mysql: mysql-command-options. (line 306) * named_pipe system variable: server-system-variables. (line 3611) * names: identifiers. (line 13) * names, case sensitivity: identifier-case-sensitivity. (line 6) * names, variables: user-variables. (line 6) * naming, releases of MySQL: choosing-version. (line 57) * NATIONAL CHAR data type: string-type-overview. (line 89) * NATIONAL VARCHAR data type: string-type-overview. (line 121) * native backup and restore, backup identifiers: mysql-cluster-backup-using-management-client. (line 105) * native functions, adding: adding-native-function. (line 6) * native thread support: supported-os. (line 6) * NATURAL LEFT JOIN: join. (line 6) * NATURAL LEFT OUTER JOIN: join. (line 6) * NATURAL RIGHT JOIN: join. (line 6) * NATURAL RIGHT OUTER JOIN: join. (line 6) * NCHAR data type: string-type-overview. (line 89) * NDB: faqs-mysql-cluster. (line 6) * NDB API, and distributed grant tables: mysql-cluster-privilege-distribution. (line 182) * NDB API, and distributed privileges: mysql-cluster-privilege-distribution. (line 182) * ndb option, perror: perror. (line 44) * NDB storage engine: mysql-cluster. (line 16) * NDB storage engine, FAQ: faqs-mysql-cluster. (line 6) * NDB tables, and MySQL root user: mysql-cluster-security-mysql-privileges. (line 51) * NDB utilities, security issues: mysql-cluster-security-mysql-security-procedures. (line 76) * NDB$MAX(): mysql-cluster-replication-conflict-resolution. (line 247) * NDB$MAX_DELETE_WIN(): mysql-cluster-replication-conflict-resolution. (line 270) * NDB$OLD: mysql-cluster-replication-conflict-resolution. (line 222) * NDB, creating large tables using: create-table. (line 814) * NDB, MAX_ROWS: create-table. (line 814) * ndb-batch-size option, mysqld: mysql-cluster-program-options-mysqld. (line 23) * ndb-blob-read-batch-bytes option, mysqld: mysql-cluster-program-options-mysqld. (line 103) * ndb-blob-write-batch-bytes option, mysqld: mysql-cluster-program-options-mysqld. (line 144) * ndb-cluster-connection-pool option, mysqld: mysql-cluster-program-options-mysqld. (line 43) * ndb-connectstring option, mysqld: mysql-cluster-program-options-mysqld. (line 186) * ndb-connectstring option, ndb_config: mysql-cluster-programs-ndb-config. (line 69) * ndb-log-apply-status option, mysqld: mysql-cluster-program-options-mysqld. (line 224) * ndb-nodeid option, mysqld: mysql-cluster-program-options-mysqld. (line 265) * ndb_apply_status table (MySQL Cluster replication) <1>: mysql-cluster-replication-failover. (line 10) * ndb_apply_status table (MySQL Cluster replication): mysql-cluster-replication-schema. (line 79) * ndb_binlog_index table (MySQL Cluster replication) <1>: mysql-cluster-replication-failover. (line 18) * ndb_binlog_index table (MySQL Cluster replication): mysql-cluster-replication-schema. (line 6) * ndb_config <1>: mysql-cluster-programs-ndb-config. (line 6) * ndb_config: mysql-cluster-programs. (line 32) * ndb_config, config-file option: mysql-cluster-programs-ndb-config. (line 91) * ndb_config, configinfo option: mysql-cluster-programs-ndb-config. (line 241) * ndb_config, fields option: mysql-cluster-programs-ndb-config. (line 201) * ndb_config, host option: mysql-cluster-programs-ndb-config. (line 128) * ndb_config, id option: mysql-cluster-programs-ndb-config. (line 157) * ndb_config, ndb-connectstring option: mysql-cluster-programs-ndb-config. (line 69) * ndb_config, nodeid option: mysql-cluster-programs-ndb-config. (line 159) * ndb_config, nodes option: mysql-cluster-programs-ndb-config. (line 165) * ndb_config, query option: mysql-cluster-programs-ndb-config. (line 99) * ndb_config, rows option: mysql-cluster-programs-ndb-config. (line 221) * ndb_config, type option: mysql-cluster-programs-ndb-config. (line 183) * ndb_config, usage option: mysql-cluster-programs-ndb-config. (line 48) * ndb_config, version option: mysql-cluster-programs-ndb-config. (line 59) * ndb_config, xml option: mysql-cluster-programs-ndb-config. (line 298) * ndb_cpcd <1>: mysql-cluster-programs-ndb-cpcd. (line 6) * ndb_cpcd: mysql-cluster-programs. (line 32) * ndb_delete_all <1>: mysql-cluster-programs-ndb-delete-all. (line 6) * ndb_delete_all: mysql-cluster-programs. (line 32) * ndb_delete_all, transactional option: mysql-cluster-programs-ndb-delete-all. (line 21) * ndb_desc <1>: mysql-cluster-programs-ndb-desc. (line 6) * ndb_desc: mysql-cluster-programs. (line 32) * ndb_desc, blob-info option: mysql-cluster-programs-ndb-desc. (line 185) * ndb_desc, extra-node-info option: mysql-cluster-programs-ndb-desc. (line 196) * ndb_desc, extra-partition-info option: mysql-cluster-programs-ndb-desc. (line 181) * ndb_dist_priv.sql: mysql-cluster-privilege-distribution. (line 11) * ndb_drop_index <1>: mysql-cluster-programs-ndb-drop-index. (line 6) * ndb_drop_index: mysql-cluster-programs. (line 32) * ndb_drop_table <1>: mysql-cluster-programs-ndb-drop-table. (line 6) * ndb_drop_table: mysql-cluster-programs. (line 32) * ndb_error_reporter <1>: mysql-cluster-programs-ndb-error-reporter. (line 6) * ndb_error_reporter: mysql-cluster-programs. (line 32) * ndb_mgm <1>: mysql-cluster-programs-ndb-mgm. (line 6) * ndb_mgm: mysql-cluster-programs. (line 32) * ndb_mgm (MySQL Cluster management node client): mysql-cluster-install-first-start. (line 34) * ndb_mgmd <1>: mysql-cluster-programs-ndb-mgmd. (line 6) * ndb_mgmd: mysql-cluster-programs. (line 32) * ndb_mgmd (MySQL Cluster process): mysql-cluster-programs-ndb-mgmd. (line 6) * ndb_mgmd (MySQL Cluster), defined: mysql-cluster-basics. (line 6) * ndb_print_backup_file <1>: mysql-cluster-programs-ndb-print-backup-file. (line 6) * ndb_print_backup_file: mysql-cluster-programs. (line 32) * ndb_print_schema_file <1>: mysql-cluster-programs-ndb-print-schema-file. (line 6) * ndb_print_schema_file: mysql-cluster-programs. (line 32) * ndb_print_sys_file <1>: mysql-cluster-programs-ndb-print-sys-file. (line 6) * ndb_print_sys_file: mysql-cluster-programs. (line 32) * ndb_replication system table: mysql-cluster-replication-conflict-resolution. (line 149) * ndb_restore: mysql-cluster-programs-ndb-restore. (line 6) * ndb_restore, -append option: mysql-cluster-programs-ndb-restore. (line 476) * ndb_restore, -disable-indexes option: mysql-cluster-programs-ndb-restore. (line 720) * ndb_restore, -exclude-databases option: mysql-cluster-programs-ndb-restore. (line 581) * ndb_restore, -exclude-missing-columns option: mysql-cluster-programs-ndb-restore. (line 702) * ndb_restore, -exclude-tables option: mysql-cluster-programs-ndb-restore. (line 593) * ndb_restore, -fields-enclosed-by option: mysql-cluster-programs-ndb-restore. (line 402) * ndb_restore, -fields-optionally-enclosed-by option: mysql-cluster-programs-ndb-restore. (line 417) * ndb_restore, -fields-terminated-by option: mysql-cluster-programs-ndb-restore. (line 434) * ndb_restore, -hex option: mysql-cluster-programs-ndb-restore. (line 450) * ndb_restore, -include-databases option: mysql-cluster-programs-ndb-restore. (line 504) * ndb_restore, -include-tables option: mysql-cluster-programs-ndb-restore. (line 516) * ndb_restore, -lossy-conversions option: mysql-cluster-programs-ndb-restore. (line 247) * ndb_restore, -print_data option: mysql-cluster-programs-ndb-restore. (line 376) * ndb_restore, -rebuild-indexes option: mysql-cluster-programs-ndb-restore. (line 737) * ndb_restore, -rewrite-database option: mysql-cluster-programs-ndb-restore. (line 787) * ndb_restore, -skip-broken-objects option: mysql-cluster-programs-ndb-restore. (line 751) * ndb_restore, -skip-unknown-objects option: mysql-cluster-programs-ndb-restore. (line 769) * ndb_restore, -tab option: mysql-cluster-programs-ndb-restore. (line 389) * ndb_restore, and circular replication: mysql-cluster-replication-multi-master. (line 79) * ndb_restore, attribute promotion: mysql-cluster-programs-ndb-restore. (line 217) * ndb_restore, errors: mysql-cluster-programs-ndb-restore. (line 839) * ndb_schema table (MySQL Cluster replication): mysql-cluster-replication-schema. (line 141) * ndb_select_all <1>: mysql-cluster-programs-ndb-select-all. (line 6) * ndb_select_all: mysql-cluster-programs. (line 32) * ndb_select_all, delimiter option: mysql-cluster-programs-ndb-select-all. (line 49) * ndb_select_all, descending option: mysql-cluster-programs-ndb-select-all. (line 34) * ndb_select_all, disk option: mysql-cluster-programs-ndb-select-all. (line 56) * ndb_select_all, gci option: mysql-cluster-programs-ndb-select-all. (line 66) * ndb_select_all, header option: mysql-cluster-programs-ndb-select-all. (line 39) * ndb_select_all, lock option: mysql-cluster-programs-ndb-select-all. (line 15) * ndb_select_all, nodata option: mysql-cluster-programs-ndb-select-all. (line 77) * ndb_select_all, order option: mysql-cluster-programs-ndb-select-all. (line 28) * ndb_select_all, rowid option: mysql-cluster-programs-ndb-select-all. (line 61) * ndb_select_all, tupscan option: mysql-cluster-programs-ndb-select-all. (line 73) * ndb_select_all, useHexFormat option: mysql-cluster-programs-ndb-select-all. (line 43) * ndb_select_count <1>: mysql-cluster-programs-ndb-select-count. (line 6) * ndb_select_count: mysql-cluster-programs. (line 32) * ndb_show_tables <1>: mysql-cluster-programs-ndb-show-tables. (line 6) * ndb_show_tables: mysql-cluster-programs. (line 32) * ndb_show_tables, database option: mysql-cluster-programs-ndb-show-tables. (line 35) * ndb_show_tables, loops option: mysql-cluster-programs-ndb-show-tables. (line 39) * ndb_show_tables, parsable option: mysql-cluster-programs-ndb-show-tables. (line 45) * ndb_show_tables, show-temp-status option: mysql-cluster-programs-ndb-show-tables. (line 50) * ndb_show_tables, type option: mysql-cluster-programs-ndb-show-tables. (line 54) * ndb_show_tables, unqualified option: mysql-cluster-programs-ndb-show-tables. (line 68) * ndb_size.pl <1>: mysql-cluster-programs-ndb-size-pl. (line 6) * ndb_size.pl: mysql-cluster-programs. (line 32) * ndb_size.pl (utility): faqs-mysql-cluster. (line 6) * ndb_waiter <1>: mysql-cluster-programs-ndb-waiter. (line 6) * ndb_waiter: mysql-cluster-programs. (line 32) * ndb_waiter, no-contact option: mysql-cluster-programs-ndb-waiter. (line 43) * ndb_waiter, not-started option: mysql-cluster-programs-ndb-waiter. (line 49) * ndb_waiter, nowait-nodes option: mysql-cluster-programs-ndb-waiter. (line 65) * ndb_waiter, single-user option: mysql-cluster-programs-ndb-waiter. (line 61) * ndb_waiter, timeout option: mysql-cluster-programs-ndb-waiter. (line 55) * ndb_waiter, wait-nodes option: mysql-cluster-programs-ndb-waiter. (line 79) * ndbcluster option, mysqld: mysql-cluster-program-options-mysqld. (line 202) * NDBCLUSTER storage engine: mysql-cluster. (line 16) * ndbd <1>: mysql-cluster-programs-ndbd. (line 6) * ndbd: mysql-cluster-programs. (line 32) * ndbd (MySQL Cluster), defined: mysql-cluster-basics. (line 6) * ndbd_redo_log_reader: mysql-cluster-programs-ndbd-redo-log-reader. (line 6) * ndbinfo database: mysql-cluster-ndbinfo. (line 20) * ndbinfo database, and query cache: mysql-cluster-ndbinfo. (line 112) * ndbinfo database, basic usage: mysql-cluster-ndbinfo. (line 146) * ndbinfo database, determining support for: mysql-cluster-ndbinfo. (line 28) * ndbmtd <1>: mysql-cluster-programs-ndbmtd. (line 6) * ndbmtd: mysql-cluster-programs. (line 32) * ndbmtd, MaxNoOfExecutionThreads: mysql-cluster-programs-ndbmtd. (line 66) * ndbmtd, trace files: mysql-cluster-programs-ndbmtd. (line 66) * negative values: number-syntax. (line 6) * nested queries: subqueries. (line 20) * nested-loop join algorithm: nested-join-optimization. (line 167) * Nested-Loop join algorithm: nested-loop-joins. (line 6) * net etiquette: mailing-list-use. (line 6) * net_buffer_length system variable: server-system-variables. (line 3627) * net_buffer_length variable: mysql-command-options. (line 626) * net_read_timeout system variable: server-system-variables. (line 3662) * net_retry_count system variable: server-system-variables. (line 3694) * net_write_timeout system variable: server-system-variables. (line 3733) * netmask notation, in account names: account-names. (line 88) * network ports, and MySQL Cluster: mysql-cluster-security-networking-issues. (line 182) * new features in MySQL 5.1: mysql-nutshell. (line 6) * new features in MySQL Cluster: mysql-cluster-development. (line 16) * new procedures, adding: adding-procedures. (line 11) * new system variable: server-system-variables. (line 3762) * new users, adding: unix-postinstallation. (line 371) * newline (\n) <1>: load-data. (line 429) * newline (\n): string-syntax. (line 60) * next-key lock, InnoDB <1>: innodb-next-key-locking. (line 6) * next-key lock, InnoDB <2>: innodb-record-level-locks. (line 6) * next-key lock, InnoDB <3>: innodb-transaction-model. (line 65) * next-key lock, InnoDB: innodb-parameters. (line 1067) * NFS, InnoDB <1>: innodb-restrictions. (line 16) * NFS, InnoDB: innodb-configuration. (line 69) * nice option, mysqld_safe: mysqld-safe. (line 191) * no matching rows: no-matching-rows. (line 6) * no-auto-rehash option, mysql: mysql-command-options. (line 313) * no-autocommit option, mysqldump: mysqldump. (line 713) * no-beep option, mysql: mysql-command-options. (line 318) * no-beep option, mysqladmin: mysqladmin. (line 358) * no-contact option, ndb_waiter: mysql-cluster-programs-ndb-waiter. (line 43) * no-create-db option, mysqldump: mysqldump. (line 719) * no-create-info option, mysqldump: mysqldump. (line 725) * no-data option, mysqldump: mysqldump. (line 737) * no-debug option, make_win_bin_dist: make-win-bin-dist. (line 52) * no-defaults option: option-file-options. (line 44) * no-defaults option, my_print_defaults: my-print-defaults. (line 53) * no-defaults option, mysqld_multi: mysqld-multi. (line 64) * no-defaults option, mysqld_safe: mysqld-safe. (line 196) * no-embedded option, make_win_bin_dist: make-win-bin-dist. (line 56) * no-log option, mysqld_multi: mysqld-multi. (line 144) * no-named-commands option, mysql: mysql-command-options. (line 322) * no-pager option, mysql: mysql-command-options. (line 327) * no-set-names option, mysqldump: mysqldump. (line 745) * no-symlinks option, myisamchk: myisamchk-repair-options. (line 51) * no-tablespaces option, mysqldump: mysqldump. (line 749) * no-tee option, mysql: mysql-command-options. (line 332) * NO_AUTO_CREATE_USER SQL mode: server-sql-mode. (line 167) * NO_AUTO_VALUE_ON_ZERO SQL mode: server-sql-mode. (line 173) * NO_BACKSLASH_ESCAPES SQL mode: server-sql-mode. (line 192) * NO_DIR_IN_CREATE SQL mode: server-sql-mode. (line 198) * NO_ENGINE_SUBSTITUTION SQL mode: server-sql-mode. (line 204) * NO_FIELD_OPTIONS SQL mode: server-sql-mode. (line 234) * NO_KEY_OPTIONS SQL mode: server-sql-mode. (line 240) * NO_TABLE_OPTIONS SQL mode: server-sql-mode. (line 246) * NO_UNSIGNED_SUBTRACTION SQL mode: server-sql-mode. (line 252) * NO_ZERO_DATE SQL mode: server-sql-mode. (line 299) * NO_ZERO_IN_DATE SQL mode: server-sql-mode. (line 305) * nodata option, ndb_select_all: mysql-cluster-programs-ndb-select-all. (line 77) * node groups (MySQL Cluster): mysql-cluster-nodes-groups. (line 6) * node logs (MySQL Cluster): mysql-cluster-event-reports. (line 12) * NodeGroup: mysql-cluster-ndbd-definition. (line 180) * NodeId <1>: mysql-cluster-api-definition. (line 60) * NodeId <2>: mysql-cluster-ndbd-definition. (line 86) * NodeId: mysql-cluster-mgm-definition. (line 50) * nodeid option, ndb_config: mysql-cluster-programs-ndb-config. (line 159) * NodeId1 <1>: mysql-cluster-sci-definition. (line 26) * NodeId1 <2>: mysql-cluster-shm-definition. (line 25) * NodeId1: mysql-cluster-tcp-definition. (line 37) * NodeId2 <1>: mysql-cluster-sci-definition. (line 37) * NodeId2 <2>: mysql-cluster-shm-definition. (line 36) * NodeId2: mysql-cluster-tcp-definition. (line 48) * NODERESTART Events (MySQL Cluster): mysql-cluster-log-events. (line 89) * nodes option, ndb_config: mysql-cluster-programs-ndb-config. (line 165) * nodes, ndbinfo table: mysql-cluster-ndbinfo-nodes. (line 6) * noindices option, mysqlhotcopy: mysqlhotcopy. (line 130) * nondelimited strings: datetime. (line 128) * Nontransactional tables: non-transactional-tables. (line 6) * NoOfDiskPagesToDiskAfterRestartACC (DEPRECATED): mysql-cluster-ndbd-definition. (line 2451) * NoOfDiskPagesToDiskAfterRestartACC, calculating: mysql-cluster-config-lcp-params. (line 6) * NoOfDiskPagesToDiskAfterRestartTUP (DEPRECATED): mysql-cluster-ndbd-definition. (line 2408) * NoOfDiskPagesToDiskAfterRestartTUP, calculating: mysql-cluster-config-lcp-params. (line 6) * NoOfDiskPagesToDiskDuringRestartACC: mysql-cluster-ndbd-definition. (line 2509) * NoOfDiskPagesToDiskDuringRestartTUP: mysql-cluster-ndbd-definition. (line 2477) * NoOfFragmentLogFiles: mysql-cluster-ndbd-definition. (line 1028) * NoOfFragmentLogFiles, calculating: mysql-cluster-config-lcp-params. (line 6) * NoOfReplicas: mysql-cluster-ndbd-definition. (line 213) * nopager command, mysql: mysql-commands. (line 139) * NOT BETWEEN: comparison-operators. (line 223) * not equal (!=): comparison-operators. (line 91) * not equal (<>): comparison-operators. (line 91) * NOT EXISTS, with subqueries: exists-and-not-exists-subqueries. (line 6) * NOT IN: comparison-operators. (line 291) * NOT LIKE: string-comparison-functions. (line 156) * NOT NULL, constraint: constraint-invalid-data. (line 6) * NOT REGEXP: regexp. (line 28) * NOT, logical: logical-operators. (line 29) * not-started option, ndb_waiter: mysql-cluster-programs-ndb-waiter. (line 49) * notee command, mysql: mysql-commands. (line 145) * NOW(): date-and-time-functions. (line 707) * NOWAIT (START BACKUP command): mysql-cluster-backup-using-management-client. (line 42) * nowait-nodes option, ndb_waiter: mysql-cluster-programs-ndb-waiter. (line 65) * nowarning command, mysql: mysql-commands. (line 150) * NUL <1>: load-data. (line 427) * NUL: string-syntax. (line 56) * NULL <1>: problems-with-null. (line 6) * NULL: working-with-null. (line 6) * NULL value <1>: null-values. (line 6) * NULL value: working-with-null. (line 6) * NULL values, and AUTO_INCREMENT columns: problems-with-null. (line 71) * NULL values, and indexes: create-table. (line 473) * NULL values, and TIMESTAMP columns: problems-with-null. (line 71) * NULL values, vs. empty values: problems-with-null. (line 6) * NULL, ORDER BY <1>: select. (line 197) * NULL, ORDER BY: order-by-optimization. (line 94) * NULL, testing for null <1>: control-flow-functions. (line 85) * NULL, testing for null: comparison-operators. (line 79) * NULL, thread state: general-thread-states. (line 175) * NULLIF(): control-flow-functions. (line 119) * Numa: mysql-cluster-ndbd-definition. (line 3320) * number-char-cols option, mysqlslap: mysqlslap. (line 356) * number-int-cols option, mysqlslap: mysqlslap. (line 361) * number-of-queries option, mysqlslap: mysqlslap. (line 366) * numbers: number-syntax. (line 6) * NUMERIC data type: numeric-type-overview. (line 246) * numeric types: storage-requirements. (line 83) * numeric-dump-file option, resolve_stack_dump: resolve-stack-dump. (line 25) * NumGeometries(): geometrycollection-property-functions. (line 21) * NumInteriorRings(): polygon-property-functions. (line 49) * NumPoints(): linestring-property-functions. (line 39) * NVARCHAR data type: string-type-overview. (line 121) * obtaining information about partitions: partitioning-info. (line 6) * OCT(): mathematical-functions. (line 327) * OCTET_LENGTH(): string-functions. (line 482) * ODBC: connector-odbc. (line 17) * ODBC compatibility <1>: join. (line 145) * ODBC compatibility <2>: create-table. (line 277) * ODBC compatibility <3>: comparison-operators. (line 153) * ODBC compatibility <4>: type-conversion. (line 44) * ODBC compatibility <5>: numeric-type-overview. (line 228) * ODBC compatibility <6>: identifier-qualifiers. (line 41) * ODBC compatibility: server-system-variables. (line 4937) * ODirect: mysql-cluster-ndbd-definition. (line 1651) * offset option, mysqlbinlog: mysqlbinlog. (line 384) * OLAP: group-by-modifiers. (line 6) * old system variable: server-system-variables. (line 3786) * old-alter-table option, mysqld: server-options. (line 1418) * old-passwords option, mysqld <1>: privileges-options. (line 56) * old-passwords option, mysqld: server-options. (line 1444) * old-style-user-limits option, mysqld: server-options. (line 1466) * old_alter_table system variable: server-system-variables. (line 3813) * OLD_PASSWORD(): encryption-functions. (line 288) * old_passwords system variable: server-system-variables. (line 3839) * old_server option, mysqlaccess: mysqlaccess. (line 103) * ON DUPLICATE KEY UPDATE: insert. (line 12) * one-database option, mysql: mysql-command-options. (line 337) * one-thread option, mysqld: server-options. (line 1483) * one_shot system variable: server-system-variables. (line 3860) * online location of manual: manual-info. (line 6) * online upgrades and downgrades (MySQL Cluster): mysql-cluster-rolling-restart. (line 6) * online upgrades and downgrades (MySQL Cluster), order of node updates: mysql-cluster-rolling-restart. (line 102) * only-debug option, make_win_bin_dist: make-win-bin-dist. (line 60) * only-print option, mysqlslap: mysqlslap. (line 379) * ONLY_FULL_GROUP_BY SQL mode: server-sql-mode. (line 314) * ONLY_FULL_GROUP_BY, SQL mode: group-by-hidden-columns. (line 6) * OPEN: open. (line 6) * Open Source, defined: what-is-mysql. (line 39) * open tables <1>: table-cache. (line 6) * open tables: mysqladmin. (line 191) * open-files-limit option, mysqld: server-options. (line 1498) * open-files-limit option, mysqld_safe: mysqld-safe. (line 201) * open_files_limit system variable: server-system-variables. (line 3865) * open_files_limit variable: mysqlbinlog. (line 539) * OpenGIS: gis-introduction. (line 6) * Opening master dump table, thread state: slave-connection-thread-states. (line 25) * Opening mysql.ndb_apply_status, thread state: mysql-cluster-thread-states. (line 8) * Opening table, thread state: general-thread-states. (line 189) * Opening tables, thread state: general-thread-states. (line 189) * opening, tables: table-cache. (line 6) * opens: mysqladmin. (line 182) * OpenSSL <1>: secure-using-ssl. (line 6) * OpenSSL: secure-connections. (line 13) * operating systems, file-size limits: table-size-limit. (line 6) * operating systems, supported: supported-os. (line 6) * operations, arithmetic: arithmetic-functions. (line 55) * operators: functions. (line 27) * operators, assignment <1>: assignment-operators. (line 6) * operators, assignment: user-variables. (line 6) * operators, cast <1>: cast-functions. (line 6) * operators, cast: arithmetic-functions. (line 6) * operators, logical: logical-operators. (line 6) * operators, precedence: operator-precedence. (line 6) * opt option, mysqldump: mysqldump. (line 758) * optimization, subquery: in-subquery-optimization. (line 6) * optimization, tips: miscellaneous-optimization-tips. (line 6) * optimizations <1>: index-merge-optimization. (line 12) * optimizations: where-optimizations. (line 6) * optimize option, mysqlcheck: mysqlcheck. (line 327) * OPTIMIZE TABLE: optimize-table. (line 6) * OPTIMIZE TABLE, and partitioning: partitioning-maintenance. (line 6) * optimizer, and replication: replication-features-optimizer. (line 6) * optimizer, controlling: controlling-optimizer. (line 11) * optimizer, query plan evaluation: controlling-query-plan-evaluation. (line 6) * optimizer, switchable optimizations: switchable-optimizations. (line 6) * optimizer_prune_level system variable: server-system-variables. (line 3890) * optimizer_search_depth system variable: server-system-variables. (line 3914) * optimizer_switch system variable <1>: switchable-optimizations. (line 6) * optimizer_switch system variable: server-system-variables. (line 3943) * optimizing, DISTINCT: distinct-optimization. (line 6) * optimizing, filesort: order-by-optimization. (line 113) * optimizing, GROUP BY: group-by-optimization. (line 11) * optimizing, LEFT JOIN: left-join-optimization. (line 6) * optimizing, LIMIT: limit-optimization. (line 6) * optimizing, tables: myisam-optimization. (line 6) * optimizing, thread state: general-thread-states. (line 198) * option files <1>: access-denied. (line 101) * option files: option-files. (line 11) * option files, escape sequences: option-files. (line 161) * option prefix, -disable: option-modifiers. (line 6) * option prefix, -enable: option-modifiers. (line 6) * option prefix, -loose: option-modifiers. (line 6) * option prefix, -maximum: option-modifiers. (line 6) * option prefix, -skip: option-modifiers. (line 6) * options, boolean: option-modifiers. (line 6) * options, command-line, mysql: mysql-command-options. (line 6) * options, command-line, mysqladmin: mysqladmin. (line 212) * options, configure: source-configuration-options. (line 6) * options, embedded server: libmysqld-options. (line 6) * options, libmysqld: libmysqld-options. (line 6) * options, myisamchk: myisamchk-general-options. (line 6) * options, provided by MySQL: tutorial. (line 16) * options, replication: replication-features. (line 43) * OR <1>: index-merge-optimization. (line 12) * OR: searching-on-two-keys. (line 6) * OR Index Merge optimization: index-merge-optimization. (line 12) * OR, bitwise: bit-functions. (line 20) * OR, logical: logical-operators. (line 65) * Oracle compatibility <1>: describe. (line 39) * Oracle compatibility <2>: group-by-functions. (line 239) * Oracle compatibility: extensions-to-ansi. (line 99) * ORACLE SQL mode: server-sql-mode. (line 489) * ORD(): string-functions. (line 486) * ORDER BY <1>: select. (line 169) * ORDER BY <2>: alter-table. (line 352) * ORDER BY: sorting-rows. (line 6) * ORDER BY, NULL <1>: select. (line 197) * ORDER BY, NULL: order-by-optimization. (line 94) * order option, ndb_select_all: mysql-cluster-programs-ndb-select-all. (line 28) * order-by-primary option, mysqldump: mysqldump. (line 772) * Out of resources error, and partitioned tables: partitioning-limitations. (line 218) * out-of-range handling: out-of-range-and-overflow. (line 6) * out_dir option, comp_err: comp-err. (line 57) * out_file option, comp_err: comp-err. (line 62) * OUTFILE: select. (line 330) * overflow handling: out-of-range-and-overflow. (line 6) * Overlaps(): functions-that-test-spatial-relationships-between-geometries. (line 53) * OverloadLimit: mysql-cluster-tcp-definition. (line 92) * overview: introduction. (line 18) * packages, list of: packages. (line 6) * PAD_CHAR_TO_FULL_LENGTH SQL mode: server-sql-mode. (line 327) * page size, InnoDB <1>: innodb-restrictions. (line 180) * page size, InnoDB: innodb-physical-structure. (line 6) * pager command, mysql: mysql-commands. (line 154) * pager option, mysql: mysql-command-options. (line 380) * parallel-recover option, myisamchk: myisamchk-repair-options. (line 63) * parameters, server: server-parameters. (line 6) * parentheses ( and ): operator-precedence. (line 48) * parsable option, ndb_show_tables: mysql-cluster-programs-ndb-show-tables. (line 45) * partial updates, and replication: replication-features-slaveerrors. (line 6) * PARTITION: partitioning. (line 14) * partition management: partitioning-management. (line 13) * partition option, mysqld: server-options. (line 1529) * partition pruning: partitioning-pruning. (line 6) * partitioning: partitioning. (line 14) * partitioning information statements: partitioning-info. (line 6) * partitioning keys and primary keys: partitioning-limitations-partitioning-keys-unique-keys. (line 6) * partitioning keys and unique keys: partitioning-limitations-partitioning-keys-unique-keys. (line 6) * partitioning, advantages: partitioning-overview. (line 143) * partitioning, and dates: partitioning-types. (line 49) * partitioning, and foreign keys: partitioning-limitations. (line 243) * partitioning, and FULLTEXT indexes: partitioning-limitations. (line 262) * partitioning, and key cache: partitioning-limitations. (line 379) * partitioning, and replication: replication-features-sql-mode. (line 6) * partitioning, and SQL mode <1>: partitioning-limitations. (line 43) * partitioning, and SQL mode: replication-features-sql-mode. (line 6) * partitioning, and subqueries: partitioning-limitations. (line 302) * partitioning, and temporary tables <1>: partitioning-limitations-partitioning-keys-unique-keys. (line 6) * partitioning, and temporary tables: partitioning-limitations. (line 272) * partitioning, by hash: partitioning-hash. (line 10) * partitioning, by key: partitioning-key. (line 6) * partitioning, by linear hash: partitioning-linear-hash. (line 6) * partitioning, by linear key: partitioning-key. (line 109) * partitioning, by list: partitioning-list. (line 6) * partitioning, by range: partitioning-range. (line 6) * partitioning, concepts: partitioning-overview. (line 6) * partitioning, data type of partitioning key: partitioning-limitations. (line 283) * partitioning, enabling: partitioning. (line 14) * partitioning, functions supported in partitioning expressions: partitioning-limitations-functions. (line 9) * partitioning, limitations: partitioning-limitations. (line 12) * Partitioning, maximum number of partitions: partitioning-limitations. (line 218) * partitioning, operators not permitted in partitioning expressions: partitioning-limitations. (line 29) * partitioning, operators supported in partitioning expressions: partitioning-limitations. (line 29) * partitioning, optimization <1>: partitioning-pruning. (line 6) * partitioning, optimization: partitioning-info. (line 62) * partitioning, resources: partitioning. (line 121) * partitioning, storage engines (limitations): partitioning-limitations-storage-engines. (line 6) * partitioning, subpartitioning: partitioning-limitations. (line 307) * partitioning, support: partitioning. (line 14) * partitioning, support in MySQL Cluster: mysql-cluster-limitations-syntax. (line 106) * partitioning, types: partitioning-types. (line 15) * partitions (MySQL Cluster): mysql-cluster-nodes-groups. (line 6) * partitions, adding and dropping: partitioning-management. (line 13) * partitions, analyzing: partitioning-maintenance. (line 6) * partitions, checking: partitioning-maintenance. (line 6) * PARTITIONS, INFORMATION_SCHEMA table: partitions-table. (line 6) * partitions, managing: partitioning-management. (line 13) * partitions, modifying: partitioning-management. (line 13) * partitions, optimizing: partitioning-maintenance. (line 6) * partitions, repairing: partitioning-maintenance. (line 6) * partitions, splitting and merging: partitioning-management. (line 13) * password encryption, reversibility of: encryption-functions. (line 309) * password option: connecting. (line 134) * password option, mysql: mysql-command-options. (line 389) * password option, mysql_convert_table_format: mysql-convert-table-format. (line 36) * password option, mysql_setpermission: mysql-setpermission. (line 37) * password option, mysqlaccess: mysqlaccess. (line 108) * password option, mysqladmin: mysqladmin. (line 364) * password option, mysqlbinlog: mysqlbinlog. (line 388) * password option, mysqlcheck: mysqlcheck. (line 331) * password option, mysqld_multi: mysqld-multi. (line 149) * password option, mysqldump: mysqldump. (line 779) * password option, mysqlhotcopy: mysqlhotcopy. (line 137) * password option, mysqlimport: mysqlimport. (line 238) * password option, mysqlmanager: instance-manager-command-options. (line 159) * password option, mysqlshow: mysqlshow. (line 168) * password option, mysqlslap: mysqlslap. (line 385) * PASSWORD() <1>: ignoring-user. (line 26) * PASSWORD() <2>: encryption-functions. (line 298) * PASSWORD() <3>: assigning-passwords. (line 6) * PASSWORD(): connection-access. (line 38) * password, root user: default-privileges. (line 6) * password-file option, mysqlmanager: instance-manager-command-options. (line 167) * passwords, administrator guidelines: password-security-admin. (line 6) * passwords, for users: user-names. (line 6) * passwords, forgotten: resetting-permissions. (line 12) * passwords, hashing: password-hashing. (line 6) * passwords, lost: resetting-permissions. (line 12) * passwords, resetting: resetting-permissions. (line 12) * passwords, security <1>: privilege-system. (line 16) * passwords, security: password-security. (line 13) * passwords, setting <1>: set-password. (line 6) * passwords, setting <2>: grant. (line 395) * passwords, setting: assigning-passwords. (line 6) * passwords, user guidelines: password-security-user. (line 6) * PATH environment variable <1>: invoking-programs. (line 48) * PATH environment variable <2>: environment-variables. (line 18) * PATH environment variable: unix-postinstallation. (line 68) * path name separators, Windows: option-files. (line 183) * pattern matching <1>: regexp. (line 6) * pattern matching: pattern-matching. (line 6) * performance, benchmarks: custom-benchmarks. (line 6) * performance, disk I/O: disk-issues. (line 6) * performance, estimating: estimating-performance. (line 6) * performance, improving <1>: replication-faq. (line 22) * performance, improving: data-size. (line 6) * PERIOD_ADD(): date-and-time-functions. (line 748) * PERIOD_DIFF(): date-and-time-functions. (line 757) * Perl API: apis-perl. (line 6) * Perl DBI/DBD, installation problems: perl-support-problems. (line 6) * Perl, installing: perl-support. (line 12) * Perl, installing on Windows: activestate-perl. (line 6) * permission checks, effect on speed: select-optimization. (line 25) * perror <1>: perror. (line 6) * perror: programs-overview. (line 279) * perror, -ndb option: faqs-mysql-cluster. (line 6) * perror, help option: perror. (line 40) * perror, ndb option: perror. (line 44) * perror, silent option: perror. (line 48) * perror, verbose option: perror. (line 52) * perror, version option: perror. (line 57) * phantom rows: innodb-next-key-locking. (line 6) * PHP API: apis-php. (line 12) * PI(): mathematical-functions. (line 336) * pid-file option, mysql.server: mysql-server. (line 44) * pid-file option, mysqld: server-options. (line 1550) * pid-file option, mysqld_safe: mysqld-safe. (line 208) * pid-file option, mysqlmanager: instance-manager-command-options. (line 175) * pid_file system variable: server-system-variables. (line 3978) * Ping, thread command: thread-commands. (line 78) * pipe option: connecting. (line 141) * pipe option, mysql <1>: mysqlcheck. (line 343) * pipe option, mysql: mysql-command-options. (line 401) * pipe option, mysqladmin: mysqladmin. (line 376) * pipe option, mysqldump: mysqldump. (line 791) * pipe option, mysqlimport: mysqlimport. (line 250) * pipe option, mysqlshow: mysqlshow. (line 180) * pipe option, mysqlslap: mysqlslap. (line 397) * PIPES_AS_CONCAT SQL mode: server-sql-mode. (line 365) * plan option, mysqlaccess: mysqlaccess. (line 117) * plugin API <1>: plugin-api. (line 13) * plugin API: server-plugins. (line 11) * plugin option prefix, mysqld: server-options. (line 1573) * plugin-load option, mysqld: server-options. (line 1598) * plugin_dir system variable: server-system-variables. (line 3998) * plugindir option, mysql_config: mysql-config. (line 39) * plugins, activating: server-plugin-loading. (line 6) * plugins, adding: plugin-api. (line 13) * plugins, daemon: daemon-plugins. (line 6) * plugins, full-text parser: full-text-plugins. (line 6) * plugins, INFORMATION_SCHEMA: information-schema-plugins. (line 6) * PLUGINS, INFORMATION_SCHEMA table: plugins-table. (line 6) * plugins, installing <1>: install-plugin. (line 6) * plugins, installing: server-plugin-loading. (line 6) * plugins, server: server-plugins. (line 11) * plugins, storage engine: storage-engine-plugins. (line 6) * plugins, uninstalling <1>: uninstall-plugin. (line 6) * plugins, uninstalling: server-plugin-loading. (line 6) * POINT data type: mysql-spatial-datatypes. (line 6) * Point(): gis-mysql-specific-functions. (line 56) * point-in-time recovery: point-in-time-recovery. (line 11) * point-in-time recovery, using MySQL Cluster replication: mysql-cluster-replication-pitr. (line 6) * PointFromText(): gis-wkt-functions. (line 45) * PointFromWKB(): gis-wkb-functions. (line 48) * PointN(): linestring-property-functions. (line 51) * PointOnSurface(): multipolygon-property-functions. (line 32) * PolyFromText(): gis-wkt-functions. (line 49) * PolyFromWKB(): gis-wkb-functions. (line 52) * POLYGON data type: mysql-spatial-datatypes. (line 6) * Polygon(): gis-mysql-specific-functions. (line 60) * PolygonFromText(): gis-wkt-functions. (line 49) * PolygonFromWKB(): gis-wkb-functions. (line 52) * pools (OBSOLETE), ndbinfo table: mysql-cluster-ndbinfo-pools. (line 6) * port option: connecting. (line 147) * port option, mysql: mysql-command-options. (line 406) * port option, mysql_config: mysql-config. (line 44) * port option, mysql_convert_table_format: mysql-convert-table-format. (line 46) * port option, mysql_setpermission: mysql-setpermission. (line 47) * port option, mysqladmin: mysqladmin. (line 381) * port option, mysqlbinlog: mysqlbinlog. (line 400) * port option, mysqlcheck: mysqlcheck. (line 348) * port option, mysqld: server-options. (line 1650) * port option, mysqld_safe: mysqld-safe. (line 212) * port option, mysqldump: mysqldump. (line 796) * port option, mysqlhotcopy: mysqlhotcopy. (line 147) * port option, mysqlimport: mysqlimport. (line 255) * port option, mysqlmanager: instance-manager-command-options. (line 182) * port option, mysqlshow: mysqlshow. (line 185) * port option, mysqlslap: mysqlslap. (line 402) * port system variable: server-system-variables. (line 4035) * port-open-timeout option, mysqld: server-options. (line 1672) * portability: portability. (line 6) * portability, types: other-vendor-data-types. (line 6) * porting, to other systems: porting. (line 12) * PortNumber: mysql-cluster-mgm-definition. (line 97) * PortNumber (OBSOLETE): mysql-cluster-tcp-definition. (line 176) * position option, mysqlbinlog: mysqlbinlog. (line 404) * POSITION(): string-functions. (line 502) * post-query option, mysqlslap: mysqlslap. (line 406) * post-system option, mysqlslap: mysqlslap. (line 418) * PostgreSQL compatibility: extensions-to-ansi. (line 193) * POSTGRESQL SQL mode: server-sql-mode. (line 495) * postinstall, multiple servers: multiple-servers. (line 13) * postinstallation, setup and testing: postinstallation. (line 11) * POW(): mathematical-functions. (line 347) * POWER(): mathematical-functions. (line 356) * pre-query option, mysqlslap: mysqlslap. (line 424) * pre-system option, mysqlslap: mysqlslap. (line 430) * precedence, operator: operator-precedence. (line 6) * precision math: precision-math. (line 14) * precision, arithmetic: precision-math. (line 14) * prefix option, configure: source-configuration-options. (line 349) * preload_buffer_size system variable: server-system-variables. (line 4056) * PREPARE <1>: prepare. (line 6) * PREPARE: sql-syntax-prepared-statements. (line 13) * Prepare, thread command: thread-commands. (line 82) * PREPARE, XA transactions: xa-statements. (line 6) * prepared statements <1>: c-api-prepared-statements. (line 6) * prepared statements <2>: deallocate-prepare. (line 6) * prepared statements <3>: execute. (line 6) * prepared statements <4>: prepare. (line 6) * prepared statements: sql-syntax-prepared-statements. (line 13) * prepared statements, repreparation: statement-repreparation. (line 6) * prepared_stmt_count system variable: server-system-variables. (line 4077) * preparing, thread state: general-thread-states. (line 202) * preserve-schema option, mysqlslap: mysqlslap. (line 436) * preview option, mysqlaccess: mysqlaccess. (line 121) * PRIMARY KEY <1>: create-table. (line 420) * PRIMARY KEY: alter-table. (line 332) * primary key, constraint: constraint-primary-key. (line 6) * primary key, deleting: alter-table. (line 329) * primary keys, and partitioning keys: partitioning-limitations-partitioning-keys-unique-keys. (line 6) * print command, mysql: mysql-commands. (line 176) * print-defaults option: option-file-options. (line 50) * print-defaults option, mysqlmanager: instance-manager-command-options. (line 187) * print-password-line option, mysqlmanager: instance-manager-command-options. (line 192) * privilege information, location: grant-table-structure. (line 6) * privilege system: privilege-system. (line 16) * privilege, changes: privilege-changes. (line 6) * privileges, access: privilege-system. (line 16) * privileges, adding: adding-users. (line 6) * privileges, and replication: replication-features-mysqldb. (line 6) * privileges, default: default-privileges. (line 6) * privileges, deleting <1>: drop-user. (line 6) * privileges, deleting: removing-users. (line 6) * privileges, display: show-grants. (line 6) * privileges, dropping <1>: drop-user. (line 6) * privileges, dropping: removing-users. (line 6) * privileges, granting: grant. (line 6) * privileges, revoking: revoke. (line 6) * problems, access denied errors: error-access-denied. (line 6) * problems, common errors: problems. (line 17) * problems, compiling: compilation-problems. (line 6) * problems, DATE columns: using-date. (line 6) * problems, date values: datetime. (line 167) * problems, installing on IBM-AIX: aix-installation. (line 10) * problems, installing on Solaris: solaris-installation. (line 11) * problems, installing Perl: perl-support-problems. (line 6) * problems, linking: c-api-linking-problems. (line 6) * problems, lost connection errors: error-lost-connection. (line 6) * problems, ODBC: connector-odbc-support. (line 14) * problems, reporting: bug-reports. (line 6) * problems, starting the server: starting-server. (line 6) * problems, table locking: table-locking. (line 6) * problems, time zone: timezone-problems. (line 6) * PROCEDURE: select. (line 324) * procedures, adding: adding-procedures. (line 11) * procedures, stored: stored-routines. (line 13) * process management (MySQL Cluster): mysql-cluster-programs. (line 32) * process support: supported-os. (line 6) * processes, display: show-processlist. (line 6) * Processing events from schema table, thread state: mysql-cluster-thread-states. (line 14) * Processing events, thread state: mysql-cluster-thread-states. (line 10) * processing, arguments: udf-arguments. (line 6) * PROCESSLIST: show-processlist. (line 6) * PROCESSLIST, INFORMATION_SCHEMA table: processlist-table. (line 6) * Processlist, thread command: thread-commands. (line 86) * profiling session variable: server-system-variables. (line 4085) * PROFILING, INFORMATION_SCHEMA table: profiling-table. (line 6) * profiling_history_size session variable: server-system-variables. (line 4093) * program options (MySQL Cluster): mysql-cluster-program-options-common. (line 6) * program variables, setting: program-variables. (line 6) * program-development utilities: programs-overview. (line 256) * programs, administrative: programs-overview. (line 165) * programs, client <1>: building-clients. (line 11) * programs, client: programs-overview. (line 124) * programs, crash-me: portability. (line 6) * programs, stored <1>: stored-programs-views. (line 16) * programs, stored: sql-syntax-compound-statements. (line 16) * programs, utility: programs-overview. (line 165) * prompt command, mysql: mysql-commands. (line 180) * prompt option, mysql: mysql-command-options. (line 410) * prompts, meanings: entering-queries. (line 134) * pronunciation, MySQL: what-is-mysql. (line 84) * protocol option: connecting. (line 152) * protocol option, mysql: mysql-command-options. (line 416) * protocol option, mysqladmin: mysqladmin. (line 385) * protocol option, mysqlbinlog: mysqlbinlog. (line 409) * protocol option, mysqlcheck: mysqlcheck. (line 352) * protocol option, mysqldump: mysqldump. (line 800) * protocol option, mysqlimport: mysqlimport. (line 259) * protocol option, mysqlshow: mysqlshow. (line 189) * protocol option, mysqlslap: mysqlslap. (line 443) * protocol_version system variable: server-system-variables. (line 4101) * pseudo_thread_id system variable: server-system-variables. (line 4114) * PURGE BINARY LOGS: purge-binary-logs. (line 6) * PURGE MASTER LOGS: purge-binary-logs. (line 6) * PURGE STALE SESSIONS: mysql-cluster-start-phases. (line 84) * Purging old relay logs, thread state: general-thread-states. (line 206) * Python API: apis-python. (line 6) * QUARTER(): date-and-time-functions. (line 766) * queries, entering: entering-queries. (line 6) * queries, estimating performance: estimating-performance. (line 6) * queries, examples: examples. (line 18) * queries, speed of: select-optimization. (line 25) * Query Cache: query-cache. (line 13) * query cache, and ndbinfo database tables: mysql-cluster-ndbinfo. (line 112) * query cache, thread states: query-cache-thread-states. (line 6) * query end, thread state: general-thread-states. (line 210) * query option, mysqlslap: mysqlslap. (line 450) * query option, ndb_config: mysql-cluster-programs-ndb-config. (line 99) * Query, thread command: thread-commands. (line 90) * query_alloc_block_size system variable: server-system-variables. (line 4127) * query_cache_limit system variable: server-system-variables. (line 4161) * query_cache_min_res_unit system variable: server-system-variables. (line 4190) * query_cache_size system variable: server-system-variables. (line 4220) * query_cache_type system variable: server-system-variables. (line 4258) * query_cache_wlock_invalidate system variable: server-system-variables. (line 4298) * query_prealloc_size system variable: server-system-variables. (line 4324) * questions: mysqladmin. (line 172) * questions, answering: mailing-list-use. (line 6) * Queueing master event to the relay log, thread state: slave-io-thread-states. (line 57) * quick option, myisamchk: myisamchk-repair-options. (line 69) * quick option, mysql: mysql-command-options. (line 423) * quick option, mysqlcheck: mysqlcheck. (line 359) * quick option, mysqldump: mysqldump. (line 807) * quiet option, mysqlhotcopy: mysqlhotcopy. (line 151) * QUIT command (MySQL Cluster): mysql-cluster-mgm-client-commands. (line 176) * quit command, mysql: mysql-commands. (line 189) * Quit, thread command: thread-commands. (line 94) * quotation marks, in strings: string-syntax. (line 93) * QUOTE(): string-functions. (line 506) * quote-names option, mysqldump: mysqldump. (line 814) * quoting: string-syntax. (line 142) * quoting binary data: string-syntax. (line 131) * quoting of identifiers: identifiers. (line 20) * quoting, column alias <1>: problems-with-alias. (line 6) * quoting, column alias: identifiers. (line 81) * RADIANS(): mathematical-functions. (line 360) * RAND(): mathematical-functions. (line 368) * rand_seed1 session variable: server-system-variables. (line 4360) * rand_seed2 session variable: server-system-variables. (line 4374) * range join type, optimizer: explain-output. (line 198) * range partitioning: partitioning-range. (line 6) * range partitions, adding and dropping: partitioning-management-range-list. (line 6) * range partitions, managing: partitioning-management-range-list. (line 6) * range_alloc_block_size system variable: server-system-variables. (line 4378) * raw option, mysql: mysql-command-options. (line 429) * re-creating, grant tables: mysql-install-db-problems. (line 104) * READ COMMITTED, transaction isolation level: set-transaction. (line 80) * READ UNCOMMITTED, transaction isolation level: set-transaction. (line 72) * read-from-remote-server option, mysqlbinlog: mysqlbinlog. (line 416) * read-only option, myisamchk: myisamchk-check-options. (line 53) * read-only option, mysqld: replication-options-slave. (line 461) * read_buffer_size myisamchk variable: myisamchk-general-options. (line 53) * read_buffer_size system variable: server-system-variables. (line 4402) * read_only system variable: server-system-variables. (line 4434) * read_rnd_buffer_size system variable: server-system-variables. (line 4503) * Reading event from the relay log, thread state: slave-sql-thread-states. (line 13) * Reading from net, thread state: general-thread-states. (line 215) * Reading master dump table data, thread state: slave-connection-thread-states. (line 29) * REAL data type: numeric-type-overview. (line 207) * REAL_AS_FLOAT SQL mode: server-sql-mode. (line 370) * RealtimeScheduler: mysql-cluster-ndbd-definition. (line 3216) * Rebuilding the index on master dump table, thread state: slave-connection-thread-states. (line 33) * ReceiveBufferMemory: mysql-cluster-tcp-definition. (line 183) * reconfiguring: compilation-problems. (line 6) * reconnect option, mysql: mysql-command-options. (line 460) * Reconnecting after a failed binlog dump request, thread state: slave-io-thread-states. (line 45) * Reconnecting after a failed master event read, thread state: slave-io-thread-states. (line 70) * reconnection, automatic: auto-reconnect. (line 6) * record-level locks, InnoDB <1>: innodb-next-key-locking. (line 6) * record-level locks, InnoDB <2>: innodb-record-level-locks. (line 6) * record-level locks, InnoDB <3>: innodb-transaction-model. (line 65) * record-level locks, InnoDB: innodb-parameters. (line 1067) * record_log_pos option, mysqlhotcopy: mysqlhotcopy. (line 155) * recover option, myisamchk: myisamchk-repair-options. (line 76) * RECOVER, XA transactions: xa-statements. (line 6) * recovery, from crash: myisam-crash-recovery. (line 6) * recovery, incremental: point-in-time-recovery. (line 11) * recovery, point in time: point-in-time-recovery. (line 11) * RedoBuffer: mysql-cluster-ndbd-definition. (line 2708) * RedoOverCommitCounter, data nodes: mysql-cluster-ndbd-definition. (line 3852) * RedoOverCommitLimit, data nodes: mysql-cluster-ndbd-definition. (line 3875) * reducing, data size: data-size. (line 6) * ref join type, optimizer: explain-output. (line 132) * ref_or_null: is-null-optimization. (line 6) * ref_or_null join type, optimizer: explain-output. (line 159) * references: alter-table. (line 405) * REFERENTIAL_CONSTRAINTS, INFORMATION_SCHEMA table: referential-constraints-table. (line 6) * Refresh, thread command: thread-commands. (line 98) * REGEXP: regexp. (line 32) * REGEXP operator: regexp. (line 6) * regexp option, mysql_find_rows: mysql-find-rows. (line 35) * regexp option, mysqlhotcopy: mysqlhotcopy. (line 160) * Register Slave, thread command: thread-commands. (line 103) * Registering slave on master, thread state: slave-io-thread-states. (line 25) * regular expression syntax: regexp. (line 6) * rehash command, mysql: mysql-commands. (line 193) * relational databases, defined: what-is-mysql. (line 39) * relative option, mysqladmin: mysqladmin. (line 392) * relay-log option, mysqld: replication-options-slave. (line 469) * relay-log-index option, mysqld: replication-options-slave. (line 514) * relay-log-info-file option, mysqld: replication-options-slave. (line 551) * relay-log-purge option, mysqld: replication-options-slave. (line 571) * relay-log-space-limit option, mysqld: replication-options-slave. (line 578) * relay_log_index system variable: replication-options-slave. (line 1246) * relay_log_info_file system variable: replication-options-slave. (line 1267) * relay_log_purge system variable: server-system-variables. (line 4537) * relay_log_space_limit system variable: server-system-variables. (line 4557) * release numbers: which-version. (line 18) * RELEASE SAVEPOINT: savepoint. (line 6) * RELEASE_LOCK(): miscellaneous-functions. (line 200) * releases, naming scheme: choosing-version. (line 57) * releases, testing: choosing-version. (line 119) * releases, updating: many-versions. (line 6) * relnotes option, mysqlaccess: mysqlaccess. (line 126) * remote administration (MySQL Cluster), and security issues: mysql-cluster-security-networking-issues. (line 189) * remove option, mysqld: server-options. (line 1692) * remove option, mysqlmanager: instance-manager-command-options. (line 200) * Removing duplicates, thread state: general-thread-states. (line 219) * removing tmp table, thread state: general-thread-states. (line 226) * RENAME DATABASE: rename-database. (line 6) * rename result table, thread state: general-thread-states. (line 236) * RENAME TABLE: rename-table. (line 6) * RENAME USER: rename-user. (line 6) * rename, thread state: general-thread-states. (line 232) * renaming user accounts: rename-user. (line 6) * Reopen tables, thread state: general-thread-states. (line 242) * Repair by sorting, thread state: general-thread-states. (line 248) * Repair done, thread state: general-thread-states. (line 252) * repair option, mysqlcheck: mysqlcheck. (line 368) * repair options, myisamchk: myisamchk-repair-options. (line 6) * REPAIR TABLE: repair-table. (line 6) * REPAIR TABLE, and partitioning: partitioning-maintenance. (line 6) * REPAIR TABLE, and replication <1>: replication-features-repair-table. (line 6) * REPAIR TABLE, and replication: repair-table. (line 132) * Repair with keycache, thread state: general-thread-states. (line 257) * repair, tables: mysqlcheck. (line 6) * repairing, tables: myisam-repair. (line 6) * REPEAT: repeat-statement. (line 6) * REPEAT(): string-functions. (line 521) * REPEATABLE READ, transaction isolation level: set-transaction. (line 115) * repertoire, character set: charset-repertoire. (line 6) * REPLACE: replace. (line 6) * replace: programs-overview. (line 284) * replace option, mysqldump: mysqldump. (line 823) * replace option, mysqlimport: mysqlimport. (line 266) * replace utility: replace-utility. (line 6) * REPLACE(): string-functions. (line 530) * replicas (MySQL Cluster): mysql-cluster-nodes-groups. (line 6) * replicate-do-db option, mysqld: replication-options-slave. (line 599) * replicate-do-table option, mysqld: replication-options-slave. (line 785) * replicate-ignore-db option, mysqld: replication-options-slave. (line 715) * replicate-ignore-table option, mysqld: replication-options-slave. (line 807) * replicate-rewrite-db option, mysqld: replication-options-slave. (line 830) * replicate-same-server-id option, mysqld: replication-options-slave. (line 859) * replicate-wild-do-table option, mysqld: replication-options-slave. (line 883) * replicate-wild-ignore-table option, mysqld: replication-options-slave. (line 930) * replication: replication. (line 13) * replication filtering options, and case sensitivity: replication-rules. (line 56) * replication formats, compared: replication-sbr-rbr. (line 6) * replication implementation: replication-implementation. (line 12) * replication limitations: replication-features. (line 43) * replication master, thread states: master-thread-states. (line 6) * replication masters, statements: replication-master-sql. (line 12) * replication options: replication-features. (line 43) * replication slave, thread states <1>: slave-connection-thread-states. (line 6) * replication slave, thread states <2>: slave-sql-thread-states. (line 6) * replication slave, thread states: slave-io-thread-states. (line 6) * replication slaves, statements: replication-slave-sql. (line 17) * replication, and AUTO_INCREMENT: replication-features-auto-increment. (line 6) * replication, and character sets: replication-features-charset. (line 6) * replication, and CREATE ... IF NOT EXISTS: replication-features-create-if-not-exists. (line 6) * replication, and CREATE TABLE ... SELECT: replication-features-create-select. (line 6) * replication, and DATA DIRECTORY: replication-features-directory. (line 6) * replication, and DROP ... IF EXISTS: replication-features-drop-if-exists. (line 6) * replication, and errors on slave: replication-features-slaveerrors. (line 6) * replication, and floating-point values: replication-features-floatvalues. (line 6) * replication, and FLUSH: replication-features-flush. (line 6) * replication, and functions: replication-features-functions. (line 6) * replication, and INDEX DIRECTORY: replication-features-directory. (line 6) * replication, and invoked features: replication-features-invoked. (line 6) * replication, and LAST_INSERT_ID(): replication-features-auto-increment. (line 6) * replication, and LIMIT: replication-features-limit. (line 6) * replication, and LOAD DATA: replication-features-load-data. (line 6) * replication, and max_allowed_packet: replication-features-max-allowed-packet. (line 6) * replication, and MEMORY tables: replication-features-memory. (line 6) * replication, and mysql (system) database: replication-features-mysqldb. (line 6) * replication, and partial updates: replication-features-slaveerrors. (line 6) * replication, and partitioning: replication-features-sql-mode. (line 6) * replication, and privileges: replication-features-mysqldb. (line 6) * replication, and query optimizer: replication-features-optimizer. (line 6) * replication, and REPAIR TABLE statement <1>: replication-features-repair-table. (line 6) * replication, and REPAIR TABLE statement: repair-table. (line 132) * replication, and reserved words: replication-features-reserved-words. (line 6) * replication, and scheduled events: replication-features-invoked. (line 6) * replication, and slow query log: replication-features-logging. (line 6) * replication, and SQL mode: replication-features-sql-mode. (line 6) * replication, and stored routines: replication-features-invoked. (line 6) * replication, and temporary tables: replication-features-temptables. (line 6) * replication, and time zones: replication-features-timezone. (line 6) * replication, and TIMESTAMP <1>: replication-features-timestamp. (line 6) * replication, and TIMESTAMP <2>: replication-features-auto-increment. (line 6) * replication, and TIMESTAMP: upgrading-from-previous-series. (line 737) * replication, and transactions <1>: replication-features-transactions. (line 6) * replication, and transactions: replication-features-timeout. (line 6) * replication, and triggers <1>: replication-features-triggers. (line 6) * replication, and triggers: replication-features-invoked. (line 6) * replication, and TRUNCATE TABLE: replication-features-truncate. (line 6) * replication, and variables: replication-features-variables. (line 6) * replication, and views: replication-features-views. (line 6) * replication, asynchronous: mysql-cluster-replication. (line 20) * replication, attribute demotion: replication-features-different-data-types. (line 6) * replication, attribute promotion: replication-features-different-data-types. (line 6) * replication, between MySQL server versions <1>: replication-features-timestamp. (line 6) * replication, between MySQL server versions: upgrading-from-previous-series. (line 737) * replication, circular: mysql-cluster-replication-issues. (line 76) * replication, crashes: replication-features-shutdowns. (line 6) * replication, in MySQL Cluster: mysql-cluster-replication. (line 20) * replication, row-based vs statement-based: replication-sbr-rbr. (line 6) * replication, safe and unsafe statements: replication-rbr-safe-unsafe. (line 6) * replication, shutdown and restart <1>: replication-features-temptables. (line 6) * replication, shutdown and restart: replication-features-shutdowns. (line 6) * replication, statements incompatible with STATEMENT format: replication-sbr-rbr. (line 30) * replication, timeouts: replication-features-timeout. (line 6) * replication, with differing tables on master and slave: replication-features-differing-tables. (line 11) * REPORT command (MySQL Cluster): mysql-cluster-mgm-client-commands. (line 126) * report-host option, mysqld: replication-options-slave. (line 956) * report-password option, mysqld: replication-options-slave. (line 982) * report-port option, mysqld: replication-options-slave. (line 1008) * report-user option, mysqld: replication-options-slave. (line 1031) * report_host system variable: server-system-variables. (line 4585) * report_password system variable: server-system-variables. (line 4604) * report_port system variable: server-system-variables. (line 4625) * report_user system variable: server-system-variables. (line 4645) * reporting, bugs: bug-reports. (line 6) * reporting, Connector/NET problems: connect-net-support. (line 12) * reporting, Connector/ODBC problems: connector-odbc-support. (line 14) * reporting, errors <1>: bug-reports. (line 6) * reporting, errors: introduction. (line 82) * Requesting binlog dump, thread state: slave-io-thread-states. (line 30) * REQUIRE GRANT option: grant. (line 492) * reschedule, thread state: delayed-insert-thread-states. (line 80) * reserved words: reserved-words. (line 6) * reserved words, and replication: replication-features-reserved-words. (line 6) * ReservedSendBufferMemory: mysql-cluster-ndbd-definition. (line 3813) * RESET MASTER: reset-master. (line 6) * RESET SLAVE: reset-slave. (line 6) * Reset stmt, thread command: thread-commands. (line 107) * reset-slave.pl: mysql-cluster-replication-auto-sync. (line 11) * resetmaster option, mysqlhotcopy: mysqlhotcopy. (line 165) * resetslave option, mysqlhotcopy: mysqlhotcopy. (line 169) * resolve_stack_dump <1>: resolve-stack-dump. (line 6) * resolve_stack_dump: programs-overview. (line 272) * resolve_stack_dump, help option: resolve-stack-dump. (line 21) * resolve_stack_dump, numeric-dump-file option: resolve-stack-dump. (line 25) * resolve_stack_dump, symbols-file option: resolve-stack-dump. (line 29) * resolve_stack_dump, version option: resolve-stack-dump. (line 33) * resolveip <1>: resolveip. (line 6) * resolveip: programs-overview. (line 289) * resolveip, help option: resolveip. (line 15) * resolveip, silent option: resolveip. (line 19) * resolveip, version option: resolveip. (line 23) * resource limits, user accounts <1>: grant. (line 460) * resource limits, user accounts <2>: user-resources. (line 6) * resource limits, user accounts: server-system-variables. (line 3289) * resources, ndbinfo table: mysql-cluster-ndbinfo-resources. (line 6) * RESTART command (MySQL Cluster): mysql-cluster-mgm-client-commands. (line 87) * restarting, the server: unix-postinstallation. (line 263) * RestartOnErrorInsert: mysql-cluster-ndbd-definition. (line 1687) * RESTORE TABLE: restore-table. (line 6) * restoring backups, in MySQL Cluster: mysql-cluster-programs-ndb-restore. (line 6) * restoring from backup, in MySQL Cluster replication: mysql-cluster-replication-backups. (line 11) * restrictions, events: stored-program-restrictions. (line 6) * restrictions, server-side cursors: cursor-restrictions. (line 6) * restrictions, stored routines: stored-program-restrictions. (line 6) * restrictions, subqueries: subquery-restrictions. (line 6) * restrictions, triggers: stored-program-restrictions. (line 6) * restrictions, views: view-restrictions. (line 6) * result-file option, mysqlbinlog: mysqlbinlog. (line 427) * result-file option, mysqldump: mysqldump. (line 829) * retrieving, data from tables: retrieving-data. (line 18) * RETURN: return. (line 6) * return (\r) <1>: load-data. (line 430) * return (\r): string-syntax. (line 61) * return values, UDFs: udf-return-values. (line 6) * REVERSE(): string-functions. (line 541) * REVOKE: revoke. (line 6) * revoking, privileges: revoke. (line 6) * rhost option, mysqlaccess: mysqlaccess. (line 130) * RIGHT JOIN: join. (line 6) * RIGHT OUTER JOIN: join. (line 6) * RIGHT(): string-functions. (line 550) * RLIKE: regexp. (line 32) * ROLLBACK <1>: commit. (line 6) * ROLLBACK: ansi-diff-transactions. (line 6) * rollback option, mysqlaccess: mysqlaccess. (line 134) * ROLLBACK TO SAVEPOINT: savepoint. (line 6) * ROLLBACK, XA transactions: xa-statements. (line 6) * Rolling back, thread state: general-thread-states. (line 262) * rolling restart (MySQL Cluster): mysql-cluster-rolling-restart. (line 6) * ROLLUP: group-by-modifiers. (line 6) * root password: default-privileges. (line 6) * root user, password resetting: resetting-permissions. (line 12) * ROUND(): mathematical-functions. (line 466) * rounding: precision-math. (line 14) * rounding errors: numeric-type-overview. (line 137) * routines option, mysqldump: mysqldump. (line 837) * ROUTINES, INFORMATION_SCHEMA table: routines-table. (line 6) * ROW: row-subqueries. (line 6) * row subqueries: row-subqueries. (line 6) * row-based replication, advantages: replication-sbr-rbr. (line 126) * row-based replication, disadvantages: replication-sbr-rbr. (line 169) * row-level locking: internal-locking. (line 6) * ROW_COUNT(): information-functions. (line 485) * rowid option, ndb_select_all: mysql-cluster-programs-ndb-select-all. (line 61) * rows option, mysql_find_rows: mysql-find-rows. (line 39) * rows option, ndb_config: mysql-cluster-programs-ndb-config. (line 221) * rows, counting: counting-rows. (line 6) * rows, deleting: deleting-from-related-tables. (line 6) * rows, locking: ansi-diff-transactions. (line 167) * rows, matching problems: no-matching-rows. (line 6) * rows, selecting: selecting-rows. (line 6) * rows, sorting: sorting-rows. (line 6) * RPAD(): string-functions. (line 560) * RPM file: linux-installation-rpm. (line 6) * rpm option, mysql_install_db: mysql-install-db. (line 65) * RPM Package Manager: linux-installation-rpm. (line 6) * RTRIM(): string-functions. (line 573) * Ruby API: apis-ruby. (line 11) * run-as-service option, mysqlmanager: instance-manager-command-options. (line 206) * running configure after prior invocation: compilation-problems. (line 14) * running, ANSI mode: ansi-mode. (line 6) * running, batch mode: batch-mode. (line 6) * running, multiple servers: multiple-servers. (line 13) * running, queries: entering-queries. (line 6) * safe statement (replication), defined: replication-rbr-safe-unsafe. (line 6) * safe-mode option, mysqld: server-options. (line 1702) * safe-recover option, myisamchk: myisamchk-repair-options. (line 89) * safe-show-database option, mysqld: server-options. (line 1712) * safe-updates option: safe-updates. (line 6) * safe-updates option, mysql: mysql-command-options. (line 467) * safe-user-create option, mysqld <1>: privileges-options. (line 62) * safe-user-create option, mysqld: server-options. (line 1733) * Sakila: history. (line 6) * same value wins (conflict resolution): mysql-cluster-replication-conflict-resolution. (line 233) * SAVEPOINT: savepoint. (line 6) * Saving state, thread state: general-thread-states. (line 266) * scale, arithmetic: precision-math. (line 14) * SchedulerExecutionTimer: mysql-cluster-ndbd-definition. (line 3233) * SchedulerSpinTimer: mysql-cluster-ndbd-definition. (line 3256) * SCHEMA(): information-functions. (line 542) * schema, altering: alter-database. (line 6) * schema, creating: create-database. (line 6) * schema, deleting: drop-database. (line 6) * SCHEMA_PRIVILEGES, INFORMATION_SCHEMA table: schema-privileges-table. (line 6) * SCHEMATA, INFORMATION_SCHEMA table: schemata-table. (line 6) * SCI (Scalable Coherent Interface) <1>: mysql-cluster-sci-sockets. (line 6) * SCI (Scalable Coherent Interface): mysql-cluster-sci-definition. (line 6) * script files: batch-mode. (line 6) * scripts <1>: mysqld-multi. (line 6) * scripts: mysqld-safe. (line 6) * scripts, mysql_install_db: mysql-install-db-problems. (line 6) * scripts, SQL: mysql. (line 15) * Searching rows for update, thread state: general-thread-states. (line 273) * searching, and case sensitivity: case-sensitivity. (line 6) * searching, full-text: fulltext-search. (line 16) * searching, MySQL Web pages: bug-reports. (line 6) * searching, two keys: searching-on-two-keys. (line 6) * SEC_TO_TIME(): date-and-time-functions. (line 780) * SECOND(): date-and-time-functions. (line 773) * secondary index, InnoDB: innodb-index-types. (line 6) * secure-auth option, mysql: mysql-command-options. (line 475) * secure-auth option, mysqld <1>: privileges-options. (line 77) * secure-auth option, mysqld: server-options. (line 1758) * secure-file-priv option, mysqld <1>: privileges-options. (line 86) * secure-file-priv option, mysqld: server-options. (line 1778) * secure_auth system variable: server-system-variables. (line 4664) * secure_file_priv system variable: server-system-variables. (line 4693) * securing a MySQL Cluster: mysql-cluster-security-mysql-security-procedures. (line 6) * security system: privilege-system. (line 16) * security, against attackers: security-against-attack. (line 6) * security, and malicious SQL statements: mysql-cluster-security-mysql-privileges. (line 86) * security, and NDB utilities: mysql-cluster-security-mysql-security-procedures. (line 76) * SELECT INTO: select-into-statement. (line 6) * SELECT INTO TABLE: ansi-diff-select-into-table. (line 6) * SELECT speed: select-speed. (line 6) * SELECT, LIMIT: select. (line 12) * SELECT, optimizing <1>: explain. (line 6) * SELECT, optimizing: using-explain. (line 6) * SELECT, Query Cache: query-cache. (line 13) * select_limit variable: mysql-command-options. (line 631) * selecting, databases: creating-database. (line 6) * semi-consistent read, InnoDB: innodb-parameters. (line 1067) * SendBufferMemory: mysql-cluster-tcp-definition. (line 105) * Sending binlog event to slave, thread state: master-thread-states. (line 11) * sending cached result to client, thread state: query-cache-thread-states. (line 24) * SendLimit: mysql-cluster-sci-definition. (line 158) * SendSignalId <1>: mysql-cluster-sci-definition. (line 173) * SendSignalId <2>: mysql-cluster-shm-definition. (line 109) * SendSignalId: mysql-cluster-tcp-definition. (line 138) * SEQUENCE: example-auto-increment. (line 6) * sequence emulation: information-functions. (line 448) * sequences: example-auto-increment. (line 6) * SERIAL: numeric-type-overview. (line 6) * SERIAL DEFAULT VALUE: data-type-defaults. (line 82) * SERIALIZABLE, transaction isolation level: set-transaction. (line 137) * server administration: mysqladmin. (line 6) * server plugins: server-plugins. (line 11) * server variables <1>: show-variables. (line 6) * server variables: server-system-variables. (line 6) * server, connecting <1>: connecting. (line 6) * server, connecting: connecting-disconnecting. (line 6) * server, debugging: debugging-server. (line 16) * server, disconnecting: connecting-disconnecting. (line 6) * server, logs: server-logs. (line 15) * server, restart: unix-postinstallation. (line 263) * server, shutdown: unix-postinstallation. (line 255) * server, signal handling: server-signal-response. (line 6) * server, starting: unix-postinstallation. (line 54) * server, starting and stopping: automatic-start. (line 6) * server, starting problems: starting-server. (line 6) * server-id option, mysqlbinlog: mysqlbinlog. (line 431) * server-id option, mysqld: replication-options. (line 21) * server-id-bits option, mysqlbinlog: mysqlbinlog. (line 436) * server-id-bits option, mysqld: mysql-cluster-program-options-mysqld. (line 315) * server-side cursor, restrictions: cursor-restrictions. (line 6) * server_id system variable: server-system-variables. (line 4718) * server_id_bits system variable: mysql-cluster-system-variables. (line 863) * ServerPort: mysql-cluster-ndbd-definition. (line 139) * servers, multiple: multiple-servers. (line 13) * service-startup-timeout option, mysql.server: mysql-server. (line 49) * session variable, autocommit: server-system-variables. (line 573) * session variable, big_tables: server-system-variables. (line 698) * session variable, error_count: server-system-variables. (line 1472) * session variable, foreign_key_checks: server-system-variables. (line 1585) * session variable, identity: server-system-variables. (line 1982) * session variable, insert_id: server-system-variables. (line 2062) * session variable, last_insert_id: server-system-variables. (line 2409) * session variable, profiling: server-system-variables. (line 4085) * session variable, profiling_history_size: server-system-variables. (line 4093) * session variable, rand_seed1: server-system-variables. (line 4360) * session variable, rand_seed2: server-system-variables. (line 4374) * session variable, sql_auto_is_null: server-system-variables. (line 4937) * session variable, sql_big_selects: server-system-variables. (line 4964) * session variable, sql_buffer_result: server-system-variables. (line 4987) * session variable, sql_log_bin: server-system-variables. (line 5005) * session variable, sql_log_off: server-system-variables. (line 5020) * session variable, sql_log_update: server-system-variables. (line 5036) * session variable, sql_notes: server-system-variables. (line 5096) * session variable, sql_quote_show_create: server-system-variables. (line 5104) * session variable, sql_safe_updates: server-system-variables. (line 5113) * session variable, sql_warnings: server-system-variables. (line 5152) * session variable, timestamp: server-system-variables. (line 5615) * session variable, transaction_allow_batching: server-system-variables. (line 5735) * session variable, unique_checks: server-system-variables. (line 5833) * session variable, warning_count: server-system-variables. (line 5975) * session variables, and replication: replication-features-variables. (line 6) * SESSION_STATUS, INFORMATION_SCHEMA table: status-table. (line 6) * SESSION_USER(): information-functions. (line 546) * SESSION_VARIABLES, INFORMATION_SCHEMA table: variables-table. (line 6) * SET <1>: set-statement. (line 6) * SET: set-option. (line 6) * SET data type <1>: set. (line 6) * SET data type: string-type-overview. (line 248) * SET GLOBAL sql_slave_skip_counter: set-global-sql-slave-skip-counter. (line 6) * SET OPTION: set-option. (line 6) * Set option, thread command: thread-commands. (line 111) * SET PASSWORD: set-password. (line 6) * SET PASSWORD statement: assigning-passwords. (line 6) * SET sql_log_bin: set-sql-log-bin. (line 6) * SET statement, assignment operator: assignment-operators. (line 70) * SET TRANSACTION: set-transaction. (line 6) * SET, CHARACTER SET <1>: set-option. (line 161) * SET, CHARACTER SET: charset-connection. (line 6) * SET, NAMES <1>: set-option. (line 177) * SET, NAMES <2>: charset-applications. (line 6) * SET, NAMES: charset-connection. (line 6) * SET, ONE_SHOT: set-option. (line 193) * SET, size: storage-requirements. (line 257) * set-auto-increment[ option, myisamchk: myisamchk-other-options. (line 28) * set-character-set option, myisamchk: myisamchk-repair-options. (line 102) * set-charset option, mysqlbinlog: mysqlbinlog. (line 450) * set-charset option, mysqldump: mysqldump. (line 864) * set-collation option, myisamchk: myisamchk-repair-options. (line 107) * setting passwords: set-password. (line 6) * setting program variables: program-variables. (line 6) * setting, passwords: assigning-passwords. (line 6) * setup, postinstallation: postinstallation. (line 11) * setup, thread state: general-thread-states. (line 287) * SHA(): encryption-functions. (line 330) * SHA1(): encryption-functions. (line 330) * shared memory transporter: mysql-cluster-shm-definition. (line 6) * shared-memory option, mysqld: server-options. (line 1802) * shared-memory-base-name option: connecting. (line 182) * shared-memory-base-name option, mysqld: server-options. (line 1807) * shared-memory-base-name option, mysqlslap: mysqlslap. (line 412) * shared_memory system variable: server-system-variables. (line 4742) * shared_memory_base_name system variable: server-system-variables. (line 4753) * SharedBufferSize: mysql-cluster-sci-definition. (line 137) * SharedGlobalMemory: mysql-cluster-ndbd-definition. (line 3379) * shell syntax: manual-conventions. (line 120) * ShmKey: mysql-cluster-shm-definition. (line 78) * ShmSize: mysql-cluster-shm-definition. (line 93) * short-form option, mysqlbinlog: mysqlbinlog. (line 456) * SHOW AUTHORS <1>: show-authors. (line 6) * SHOW AUTHORS: show. (line 51) * SHOW BINARY LOGS <1>: show-binary-logs. (line 6) * SHOW BINARY LOGS: show. (line 51) * SHOW BINLOG EVENTS <1>: show-binlog-events. (line 6) * SHOW BINLOG EVENTS: show. (line 51) * SHOW CHARACTER SET <1>: show-character-set. (line 6) * SHOW CHARACTER SET: show. (line 51) * SHOW COLLATION <1>: show-collation. (line 6) * SHOW COLLATION: show. (line 51) * SHOW COLUMNS <1>: show-columns. (line 6) * SHOW COLUMNS: show. (line 51) * SHOW command (MySQL Cluster): mysql-cluster-mgm-client-commands. (line 24) * SHOW CONTRIBUTORS <1>: show-contributors. (line 6) * SHOW CONTRIBUTORS: show. (line 51) * SHOW CREATE DATABASE <1>: show-create-database. (line 6) * SHOW CREATE DATABASE: show. (line 51) * SHOW CREATE EVENT: show. (line 51) * SHOW CREATE FUNCTION <1>: show-create-function. (line 6) * SHOW CREATE FUNCTION: show. (line 51) * SHOW CREATE PROCEDURE <1>: show-create-procedure. (line 6) * SHOW CREATE PROCEDURE: show. (line 51) * SHOW CREATE SCHEMA <1>: show-create-database. (line 6) * SHOW CREATE SCHEMA: show. (line 51) * SHOW CREATE TABLE <1>: show-create-table. (line 6) * SHOW CREATE TABLE: show. (line 51) * SHOW CREATE TRIGGER <1>: show-create-trigger. (line 6) * SHOW CREATE TRIGGER: show. (line 51) * SHOW CREATE VIEW <1>: show-create-view. (line 6) * SHOW CREATE VIEW: show. (line 51) * SHOW DATABASES <1>: show-databases. (line 6) * SHOW DATABASES: show. (line 51) * SHOW ENGINE <1>: show-engine. (line 6) * SHOW ENGINE: show. (line 51) * SHOW ENGINE INNODB STATUS: show-engine. (line 6) * SHOW ENGINE NDB STATUS <1>: mysql-cluster-sql-statements. (line 10) * SHOW ENGINE NDB STATUS: show-engine. (line 6) * SHOW ENGINE NDBCLUSTER STATUS <1>: mysql-cluster-sql-statements. (line 10) * SHOW ENGINE NDBCLUSTER STATUS: show-engine. (line 6) * SHOW ENGINE, and MySQL Cluster: mysql-cluster-sql-statements. (line 10) * SHOW ENGINES <1>: show-engines. (line 6) * SHOW ENGINES: show. (line 51) * SHOW ENGINES, and MySQL Cluster: mysql-cluster-sql-statements. (line 20) * SHOW ERRORS <1>: show-errors. (line 6) * SHOW ERRORS: show. (line 51) * SHOW ERRORS, and MySQL Cluster: faqs-mysql-cluster. (line 6) * SHOW EVENTS <1>: show-events. (line 6) * SHOW EVENTS: show. (line 51) * SHOW extensions: extended-show. (line 6) * SHOW FIELDS <1>: show-columns. (line 99) * SHOW FIELDS: show. (line 51) * SHOW FUNCTION CODE <1>: show-function-code. (line 6) * SHOW FUNCTION CODE: show. (line 51) * SHOW FUNCTION STATUS <1>: show-function-status. (line 6) * SHOW FUNCTION STATUS: show. (line 51) * SHOW GRANTS <1>: show-grants. (line 6) * SHOW GRANTS: show. (line 51) * SHOW INDEX <1>: show-index. (line 6) * SHOW INDEX: show. (line 51) * SHOW INNODB STATUS: show. (line 51) * SHOW KEYS <1>: show-index. (line 6) * SHOW KEYS: show. (line 51) * SHOW MASTER LOGS <1>: show-binary-logs. (line 6) * SHOW MASTER LOGS: show. (line 51) * SHOW MASTER STATUS <1>: show-master-status. (line 6) * SHOW MASTER STATUS: show. (line 51) * SHOW OPEN TABLES <1>: show-open-tables. (line 6) * SHOW OPEN TABLES: show. (line 51) * SHOW PLUGINS <1>: show-plugins. (line 6) * SHOW PLUGINS: show. (line 51) * SHOW PRIVILEGES <1>: show-privileges. (line 6) * SHOW PRIVILEGES: show. (line 51) * SHOW PROCEDURE CODE <1>: show-procedure-code. (line 6) * SHOW PROCEDURE CODE: show. (line 51) * SHOW PROCEDURE STATUS <1>: show-procedure-status. (line 6) * SHOW PROCEDURE STATUS: show. (line 51) * SHOW PROCESSLIST <1>: show-processlist. (line 6) * SHOW PROCESSLIST: show. (line 51) * SHOW PROFILE <1>: show-profiles. (line 6) * SHOW PROFILE <2>: show-profile. (line 6) * SHOW PROFILE: show. (line 51) * SHOW PROFILES <1>: show-profiles. (line 6) * SHOW PROFILES: show. (line 51) * SHOW SCHEDULER STATUS <1>: events-status-info. (line 6) * SHOW SCHEDULER STATUS: show. (line 51) * SHOW SCHEMAS <1>: show-databases. (line 6) * SHOW SCHEMAS: show. (line 51) * SHOW SLAVE HOSTS <1>: show-slave-hosts. (line 6) * SHOW SLAVE HOSTS: show. (line 51) * SHOW SLAVE STATUS <1>: show-slave-status. (line 6) * SHOW SLAVE STATUS: show. (line 51) * SHOW STATUS: show. (line 51) * SHOW STATUS, and MySQL Cluster: mysql-cluster-sql-statements. (line 125) * SHOW STORAGE ENGINES: show-engines. (line 6) * SHOW TABLE STATUS: show. (line 51) * SHOW TABLE TYPES: show-engines. (line 6) * SHOW TABLES <1>: show-tables. (line 6) * SHOW TABLES: show. (line 51) * SHOW TRIGGERS <1>: show-triggers. (line 6) * SHOW TRIGGERS: show. (line 51) * SHOW VARIABLES: show. (line 51) * SHOW VARIABLES, and MySQL Cluster: mysql-cluster-sql-statements. (line 58) * SHOW WARNINGS <1>: show-warnings. (line 6) * SHOW WARNINGS: show. (line 51) * SHOW WARNINGS, and MySQL Cluster: faqs-mysql-cluster. (line 6) * SHOW with WHERE <1>: extended-show. (line 6) * SHOW with WHERE: information-schema. (line 37) * SHOW, in MySQL Cluster management client: mysql-cluster-quick. (line 145) * show-slave-auth-info option, mysqld: replication-options-slave. (line 1057) * show-table-type option, mysqlshow: mysqlshow. (line 196) * show-temp-status option, ndb_show_tables: mysql-cluster-programs-ndb-show-tables. (line 50) * show-warnings option, mysql: mysql-command-options. (line 481) * showing, database information: mysqlshow. (line 6) * SHUTDOWN command (MySQL Cluster): mysql-cluster-mgm-client-commands. (line 182) * Shutdown, thread command: thread-commands. (line 116) * shutdown_timeout variable: mysqladmin. (line 451) * shutting down, the server: unix-postinstallation. (line 255) * Shutting down, thread state: mysql-cluster-thread-states. (line 18) * sigint-ignore option, mysql: mysql-command-options. (line 486) * SIGN(): mathematical-functions. (line 526) * signals, server response: server-signal-response. (line 6) * SigNum: mysql-cluster-shm-definition. (line 145) * silent column changes: silent-column-changes. (line 6) * silent option, myisamchk: myisamchk-general-options. (line 27) * silent option, myisampack: myisampack. (line 93) * silent option, mysql: mysql-command-options. (line 490) * silent option, mysqladmin: mysqladmin. (line 398) * silent option, mysqlcheck: mysqlcheck. (line 373) * silent option, mysqld_multi: mysqld-multi. (line 155) * silent option, mysqlimport: mysqlimport. (line 276) * silent option, mysqlslap: mysqlslap. (line 455) * silent option, perror: perror. (line 48) * silent option, resolveip: resolveip. (line 19) * SIN(): mathematical-functions. (line 538) * single quote (\'): string-syntax. (line 57) * single user mode (MySQL Cluster) <1>: mysql-cluster-single-user-mode. (line 6) * single user mode (MySQL Cluster): mysql-cluster-mgm-client-commands. (line 158) * single user mode (MySQL Cluster), and ndb_restore: mysql-cluster-programs-ndb-restore. (line 19) * single-transaction option, mysqldump: mysqldump. (line 870) * single-user option, ndb_waiter: mysql-cluster-programs-ndb-waiter. (line 61) * size of tables: table-size-limit. (line 6) * sizes, display: data-types. (line 32) * skip-column-names option, mysql: mysql-command-options. (line 499) * skip-comments option, mysqldump: mysqldump. (line 908) * skip-concurrent-insert option, mysqld: server-options. (line 1813) * skip-event-scheduler option, mysqld: server-options. (line 1828) * skip-external-locking option, mysqld: server-options. (line 1819) * skip-grant-tables option, mysqld <1>: privileges-options. (line 95) * skip-grant-tables option, mysqld: server-options. (line 1841) * skip-host-cache option, mysqld: server-options. (line 1860) * skip-innodb option, mysqld <1>: innodb-parameters. (line 197) * skip-innodb option, mysqld: server-options. (line 1866) * skip-kill-mysqld option, mysqld_safe: mysqld-safe. (line 218) * skip-line-numbers option, mysql: mysql-command-options. (line 503) * skip-merge option, mysqld: privileges-options. (line 114) * skip-name-resolve option, mysql_install_db: mysql-install-db. (line 70) * skip-name-resolve option, mysqld <1>: privileges-options. (line 119) * skip-name-resolve option, mysqld: server-options. (line 1873) * skip-ndbcluster option, mysqld: mysql-cluster-program-options-mysqld. (line 363) * skip-networking option, mysqld <1>: privileges-options. (line 124) * skip-networking option, mysqld: server-options. (line 1880) * skip-opt option, mysqldump: mysqldump. (line 912) * skip-partition option, mysqld: server-options. (line 1888) * skip-safemalloc option, mysqld: server-options. (line 1940) * skip-show-database option, mysqld <1>: privileges-options. (line 129) * skip-show-database option, mysqld: server-options. (line 1953) * skip-slave-start option, mysqld: replication-options-slave. (line 1074) * skip-stack-trace option, mysqld: server-options. (line 1974) * skip-symbolic-links option, mysqld: server-options. (line 1917) * skip-syslog option, mysqld_safe: mysqld-safe. (line 228) * skip-thread-priority option, mysqld: server-options. (line 1987) * skip-use-db option, mysql_find_rows: mysql-find-rows. (line 43) * skip_external_locking system variable: server-system-variables. (line 4766) * skip_name_resolve system variable: server-system-variables. (line 4772) * skip_networking system variable: server-system-variables. (line 4782) * skip_show_database system variable: server-system-variables. (line 4791) * slave option, mysqlslap: mysqlslap. (line 459) * slave-load-tmpdir option, mysqld: replication-options-slave. (line 1111) * slave-net-timeout option, mysqld: replication-options-slave. (line 1133) * slave-skip-errors option, mysqld: replication-options-slave. (line 1161) * slave_allow_batching: mysql-cluster-replication-starting. (line 88) * slave_compressed_protocol option, mysqld: replication-options-slave. (line 1090) * slave_compressed_protocol system variable: replication-options-slave. (line 1292) * slave_exec_mode system variable: replication-options-slave. (line 1312) * slave_load_tmpdir system variable: replication-options-slave. (line 1345) * slave_net_timeout system variable: replication-options-slave. (line 1366) * slave_skip_errors system variable: replication-options-slave. (line 1389) * slave_transaction_retries system variable: replication-options-slave. (line 1407) * slave_type_conversions system variable: replication-options-slave. (line 1443) * sleep option, mysqladmin: mysqladmin. (line 402) * SLEEP(): miscellaneous-functions. (line 216) * Sleep, thread command: thread-commands. (line 120) * slow queries: mysqladmin. (line 177) * slow query log: slow-query-log. (line 6) * slow query log, and replication: replication-features-logging. (line 6) * slow-query-log option, mysqld: server-options. (line 2008) * slow_launch_time system variable: server-system-variables. (line 4806) * slow_query_log system variable: server-system-variables. (line 4826) * slow_query_log_file system variable: server-system-variables. (line 4837) * SMALLINT data type: numeric-type-overview. (line 106) * SNAPSHOTEND (START BACKUP command): mysql-cluster-backup-using-management-client. (line 64) * SNAPSHOTSTART (START BACKUP command): mysql-cluster-backup-using-management-client. (line 64) * socket location, changing: source-configuration-options. (line 377) * socket option: connecting. (line 191) * socket option, mysql: mysql-command-options. (line 508) * socket option, mysql_config: mysql-config. (line 48) * socket option, mysql_convert_table_format: mysql-convert-table-format. (line 50) * socket option, mysql_setpermission: mysql-setpermission. (line 51) * socket option, mysqladmin: mysqladmin. (line 409) * socket option, mysqlbinlog: mysqlbinlog. (line 462) * socket option, mysqlcheck: mysqlcheck. (line 377) * socket option, mysqld: server-options. (line 2031) * socket option, mysqld_safe: mysqld-safe. (line 223) * socket option, mysqldump: mysqldump. (line 916) * socket option, mysqlhotcopy: mysqlhotcopy. (line 173) * socket option, mysqlimport: mysqlimport. (line 280) * socket option, mysqlmanager: instance-manager-command-options. (line 212) * socket option, mysqlshow: mysqlshow. (line 201) * socket option, mysqlslap: mysqlslap. (line 466) * socket system variable: server-system-variables. (line 4860) * Solaris installation problems: solaris-installation. (line 11) * Solaris troubleshooting: compilation-problems. (line 133) * Solaris x86_64 issues: innodb-tuning. (line 6) * Solaris, installation: solaris-installation. (line 11) * SOME: any-in-some-subqueries. (line 6) * sort-index option, myisamchk: myisamchk-other-options. (line 36) * sort-records option, myisamchk: myisamchk-other-options. (line 41) * sort-recover option, myisamchk: myisamchk-repair-options. (line 113) * sort_buffer_size myisamchk variable: myisamchk-general-options. (line 53) * sort_buffer_size system variable: server-system-variables. (line 4887) * sort_key_blocks myisamchk variable: myisamchk-general-options. (line 53) * Sorting for group, thread state: general-thread-states. (line 292) * Sorting for order, thread state: general-thread-states. (line 296) * Sorting index, thread state: general-thread-states. (line 300) * Sorting result, thread state: general-thread-states. (line 305) * sorting, data: sorting-rows. (line 6) * sorting, grant tables <1>: request-access. (line 51) * sorting, grant tables: connection-access. (line 120) * sorting, table rows: sorting-rows. (line 6) * SOUNDEX(): string-functions. (line 582) * SOUNDS LIKE: string-functions. (line 621) * source (mysql client command) <1>: batch-commands. (line 6) * source (mysql client command): batch-mode. (line 90) * source command, mysql: mysql-commands. (line 199) * source distribution, installing: source-installation. (line 19) * SPACE(): string-functions. (line 625) * spassword option, mysqlaccess: mysqlaccess. (line 138) * Spatial Extensions in MySQL: gis-introduction. (line 6) * speed, compiling: compile-and-link-options. (line 6) * speed, increasing with replication: replication. (line 13) * speed, inserting: insert-speed. (line 6) * speed, linking: compile-and-link-options. (line 6) * speed, of queries <1>: select-speed. (line 6) * speed, of queries: select-optimization. (line 25) * sporadic-binlog-dump-fail option, mysqld: replication-options-binary-log. (line 342) * SQL mode: server-sql-mode. (line 6) * SQL mode, ALLOW_INVALID_DATES: server-sql-mode. (line 91) * SQL mode, and partitioning <1>: partitioning-limitations. (line 43) * SQL mode, and partitioning: replication-features-sql-mode. (line 6) * SQL mode, and replication: replication-features-sql-mode. (line 6) * SQL mode, ANSI: server-sql-mode. (line 59) * SQL mode, ANSI_QUOTES: server-sql-mode. (line 109) * SQL mode, DB2: server-sql-mode. (line 465) * SQL mode, ERROR_FOR_DIVISION_BY_ZERO: server-sql-mode. (line 117) * SQL mode, HIGH_NOT_PRECEDENCE: server-sql-mode. (line 127) * SQL mode, IGNORE_SPACE: server-sql-mode. (line 142) * SQL mode, MAXDB: server-sql-mode. (line 470) * SQL mode, MSSQL: server-sql-mode. (line 476) * SQL mode, MYSQL323: server-sql-mode. (line 481) * SQL mode, MYSQL40: server-sql-mode. (line 485) * SQL mode, NO_AUTO_CREATE_USER: server-sql-mode. (line 167) * SQL mode, NO_AUTO_VALUE_ON_ZERO: server-sql-mode. (line 173) * SQL mode, NO_BACKSLASH_ESCAPES: server-sql-mode. (line 192) * SQL mode, NO_DIR_IN_CREATE: server-sql-mode. (line 198) * SQL mode, NO_ENGINE_SUBSTITUTION: server-sql-mode. (line 204) * SQL mode, NO_FIELD_OPTIONS: server-sql-mode. (line 234) * SQL mode, NO_KEY_OPTIONS: server-sql-mode. (line 240) * SQL mode, NO_TABLE_OPTIONS: server-sql-mode. (line 246) * SQL mode, NO_UNSIGNED_SUBTRACTION: server-sql-mode. (line 252) * SQL mode, NO_ZERO_DATE: server-sql-mode. (line 299) * SQL mode, NO_ZERO_IN_DATE: server-sql-mode. (line 305) * SQL mode, ONLY_FULL_GROUP_BY <1>: group-by-hidden-columns. (line 6) * SQL mode, ONLY_FULL_GROUP_BY: server-sql-mode. (line 314) * SQL mode, ORACLE: server-sql-mode. (line 489) * SQL mode, PAD_CHAR_TO_FULL_LENGTH: server-sql-mode. (line 327) * SQL mode, PIPES_AS_CONCAT: server-sql-mode. (line 365) * SQL mode, POSTGRESQL: server-sql-mode. (line 495) * SQL mode, REAL_AS_FLOAT: server-sql-mode. (line 370) * SQL mode, strict: server-sql-mode. (line 86) * SQL mode, STRICT_ALL_TABLES: server-sql-mode. (line 376) * SQL mode, STRICT_TRANS_TABLES: server-sql-mode. (line 64) * SQL mode, TRADITIONAL: server-sql-mode. (line 72) * SQL node (MySQL Cluster), defined: mysql-cluster-basics. (line 6) * SQL nodes (MySQL Cluster): mysql-cluster-programs-mysqld. (line 6) * SQL scripts: mysql. (line 15) * SQL statements relating to MySQL Cluster: mysql-cluster-sql-statements. (line 6) * SQL statements, replication masters: replication-master-sql. (line 12) * SQL statements, replication slaves: replication-slave-sql. (line 17) * SQL, defined: what-is-mysql. (line 39) * SQL-92, extensions to: compatibility. (line 15) * sql-mode option, mysqld: server-options. (line 2058) * sql_auto_is_null session variable: server-system-variables. (line 4937) * SQL_BIG_RESULT: select. (line 504) * sql_big_selects session variable: server-system-variables. (line 4964) * SQL_BUFFER_RESULT: select. (line 513) * sql_buffer_result session variable: server-system-variables. (line 4987) * SQL_CACHE <1>: select. (line 525) * SQL_CACHE: query-cache-in-select. (line 9) * SQL_CALC_FOUND_ROWS: select. (line 520) * sql_log_bin session variable: server-system-variables. (line 5005) * sql_log_off session variable: server-system-variables. (line 5020) * sql_log_update session variable: server-system-variables. (line 5036) * sql_mode system variable: server-system-variables. (line 5053) * SQL_NO_CACHE <1>: select. (line 525) * SQL_NO_CACHE: query-cache-in-select. (line 9) * sql_notes session variable: server-system-variables. (line 5096) * sql_quote_show_create session variable: server-system-variables. (line 5104) * sql_safe_updates session variable: server-system-variables. (line 5113) * sql_select_limit system variable: server-system-variables. (line 5122) * sql_slave_skip_counter: set-global-sql-slave-skip-counter. (line 6) * sql_slave_skip_counter system variable: replication-options-slave. (line 1480) * SQL_SMALL_RESULT: select. (line 504) * sql_warnings session variable: server-system-variables. (line 5152) * sql_yacc.cc problems: compilation-problems. (line 37) * SQRT(): mathematical-functions. (line 547) * square brackets: data-types. (line 42) * srcdir option, mysql_install_db: mysql-install-db. (line 75) * SRID(): general-geometry-property-functions. (line 51) * SSH: windows-and-ssh. (line 6) * SSL: secure-using-ssl. (line 6) * SSL and X509 Basics: secure-connections. (line 13) * SSL command options: ssl-options. (line 6) * ssl option: ssl-options. (line 38) * SSL options: connecting. (line 204) * SSL options, mysql: mysql-command-options. (line 513) * SSL options, mysqladmin: mysqladmin. (line 414) * SSL options, mysqlcheck: mysqlcheck. (line 382) * SSL options, mysqld <1>: privileges-options. (line 139) * SSL options, mysqld: server-options. (line 1900) * SSL options, mysqldump: mysqldump. (line 921) * SSL options, mysqlimport: mysqlimport. (line 285) * SSL options, mysqlshow: mysqlshow. (line 206) * SSL options, mysqlslap: mysqlslap. (line 471) * SSL related options: grant. (line 492) * ssl-ca option: ssl-options. (line 67) * ssl-capath option: ssl-options. (line 71) * ssl-cert option: ssl-options. (line 76) * ssl-cipher option: ssl-options. (line 81) * ssl-key option: ssl-options. (line 100) * ssl-verify-server-cert option: ssl-options. (line 105) * ssl_ca system variable: server-system-variables. (line 5158) * ssl_capath system variable: server-system-variables. (line 5179) * ssl_cert system variable: server-system-variables. (line 5200) * ssl_cipher system variable: server-system-variables. (line 5221) * ssl_key system variable: server-system-variables. (line 5242) * standalone option, mysqld: server-options. (line 1906) * standalone option, mysqlmanager: instance-manager-command-options. (line 218) * Standard Monitor, InnoDB: innodb-monitors. (line 12) * Standard SQL, differences from <1>: grant. (line 605) * Standard SQL, differences from: differences-from-ansi. (line 14) * Standard SQL, extensions to <1>: extensions-to-ansi. (line 6) * Standard SQL, extensions to: compatibility. (line 15) * standards compatibility: compatibility. (line 15) * START BACKUP, NOWAIT: mysql-cluster-backup-using-management-client. (line 42) * START BACKUP, SNAPSHOTEND: mysql-cluster-backup-using-management-client. (line 64) * START BACKUP, SNAPSHOTSTART: mysql-cluster-backup-using-management-client. (line 64) * START BACKUP, syntax: mysql-cluster-backup-using-management-client. (line 10) * START BACKUP, WAIT COMPLETED: mysql-cluster-backup-using-management-client. (line 59) * START BACKUP, WAIT STARTED: mysql-cluster-backup-using-management-client. (line 51) * START command (MySQL Cluster): mysql-cluster-mgm-client-commands. (line 43) * START SLAVE: start-slave. (line 6) * START TRANSACTION: commit. (line 6) * START, XA transactions: xa-statements. (line 6) * start-datetime option, mysqlbinlog: mysqlbinlog. (line 467) * start-position option, mysqlbinlog: mysqlbinlog. (line 481) * start_row option, mysql_find_rows: mysql-find-rows. (line 47) * StartFailRetryDelay: mysql-cluster-ndbd-definition. (line 3914) * StartFailureTimeout: mysql-cluster-ndbd-definition. (line 1860) * Starting many servers: multiple-servers. (line 13) * starting slave, thread state: slave-connection-thread-states. (line 37) * starting, comments: ansi-diff-comments. (line 6) * starting, mysqld: changing-mysql-user. (line 6) * starting, the server: unix-postinstallation. (line 54) * starting, the server automatically: automatic-start. (line 6) * StartNoNodeGroupTimeout: mysql-cluster-ndbd-definition. (line 1883) * StartPartialTimeout: mysql-cluster-ndbd-definition. (line 1815) * StartPartitionedTimeout: mysql-cluster-ndbd-definition. (line 1838) * StartPoint(): linestring-property-functions. (line 64) * STARTUP Events (MySQL Cluster): mysql-cluster-log-events. (line 54) * startup options, default: option-files. (line 11) * startup parameters: server-parameters. (line 6) * startup parameters, mysql: mysql-command-options. (line 6) * startup parameters, mysqladmin: mysqladmin. (line 212) * startup parameters, tuning: system-optimization. (line 6) * StartupStatusReportFrequency: mysql-cluster-ndbd-definition. (line 2941) * statefile option, comp_err: comp-err. (line 66) * statement-based replication, advantages: replication-sbr-rbr. (line 16) * statement-based replication, disadvantages: replication-sbr-rbr. (line 28) * statement-based replication, unsafe statements: replication-sbr-rbr. (line 30) * statements, compound: sql-syntax-compound-statements. (line 16) * statements, GRANT: adding-users. (line 6) * statements, INSERT: adding-users. (line 116) * statements, replication masters: replication-master-sql. (line 12) * statements, replication slaves: replication-slave-sql. (line 17) * statically, compiling: source-configuration-options. (line 389) * STATISTICS Events (MySQL Cluster): mysql-cluster-log-events. (line 172) * STATISTICS, INFORMATION_SCHEMA table: statistics-table. (line 6) * Statistics, thread command: thread-commands. (line 124) * statistics, thread state: general-thread-states. (line 310) * stats option, myisam_ftdump: myisam-ftdump. (line 74) * stats_method myisamchk variable: myisamchk-general-options. (line 53) * STATUS command (MySQL Cluster): mysql-cluster-mgm-client-commands. (line 117) * status command, mysql: mysql-commands. (line 204) * status command, results: mysqladmin. (line 161) * status option, mysqlshow: mysqlshow. (line 212) * status variables <1>: show-status. (line 6) * status variables: server-status-variables. (line 6) * status, tables: show-table-status. (line 6) * STD(): group-by-functions. (line 231) * STDDEV(): group-by-functions. (line 239) * STDDEV_POP(): group-by-functions. (line 247) * STDDEV_SAMP(): group-by-functions. (line 255) * STOP command (MySQL Cluster): mysql-cluster-mgm-client-commands. (line 58) * STOP SLAVE: stop-slave. (line 6) * stop-datetime option, mysqlbinlog: mysqlbinlog. (line 490) * stop-position option, mysqlbinlog: mysqlbinlog. (line 500) * StopOnError: mysql-cluster-ndbd-definition. (line 1604) * stopping, the server: automatic-start. (line 6) * stopword list, user-defined: fulltext-fine-tuning. (line 40) * storage engine plugins: storage-engine-plugins. (line 6) * storage engine, ARCHIVE: archive-storage-engine. (line 6) * storage engines, and application feature requirements: mysql-cluster-ndb-innodb-usage. (line 6) * storage engines, applications supported: mysql-cluster-ndb-innodb-workloads. (line 6) * storage engines, availability: mysql-cluster-compared. (line 36) * storage engines, choosing: storage-engines. (line 23) * storage engines, differences between NDB and InnoDB: mysql-cluster-ndb-innodb-engines. (line 6) * storage engines, usage scenarios: mysql-cluster-ndb-innodb-usage. (line 6) * storage nodes - see data nodes, ndbd: mysql-cluster-programs-ndbd. (line 6) * storage nodes - see data nodes, ndbd, ndbmtd: mysql-cluster-programs-ndbmtd. (line 6) * storage requirements, data type: storage-requirements. (line 6) * storage space, minimizing: data-size. (line 6) * storage_engine system variable: server-system-variables. (line 5262) * stored functions: stored-routines. (line 13) * stored functions, and INSERT DELAYED: insert. (line 230) * stored procedures: stored-routines. (line 13) * stored programs <1>: stored-programs-views. (line 16) * stored programs: sql-syntax-compound-statements. (line 16) * stored routine, restrictions: stored-program-restrictions. (line 6) * stored routines, and replication: replication-features-invoked. (line 6) * stored routines, LAST_INSERT_ID(): stored-routines-last-insert-id. (line 6) * stored routines, metadata: stored-routines-metadata. (line 6) * storing result in query cache, thread state: query-cache-thread-states. (line 29) * storing row into queue, thread state: delayed-insert-thread-states. (line 39) * STR_TO_DATE(): date-and-time-functions. (line 793) * STRAIGHT_JOIN <1>: join. (line 6) * STRAIGHT_JOIN <2>: select. (line 487) * STRAIGHT_JOIN <3>: left-join-optimization. (line 38) * STRAIGHT_JOIN <4>: explain-output. (line 677) * STRAIGHT_JOIN: using-explain. (line 33) * STRCMP(): string-comparison-functions. (line 182) * strict SQL mode: server-sql-mode. (line 86) * STRICT_ALL_TABLES SQL mode: server-sql-mode. (line 376) * STRICT_TRANS_TABLES SQL mode: server-sql-mode. (line 64) * string collating: string-collating. (line 6) * string comparison functions: string-comparison-functions. (line 6) * string comparisons, case sensitivity: string-comparison-functions. (line 17) * string concatenation <1>: string-functions. (line 187) * string concatenation: string-syntax. (line 12) * string functions: string-functions. (line 11) * string literal introducer <1>: charset-literal. (line 11) * string literal introducer: string-syntax. (line 33) * string replacement, replace utility: replace-utility. (line 6) * string types <1>: storage-requirements. (line 154) * string types: string-types. (line 14) * StringMemory: mysql-cluster-ndbd-definition. (line 497) * strings, defined: string-syntax. (line 6) * strings, escape sequences: string-syntax. (line 6) * strings, nondelimited: datetime. (line 128) * striping, defined: disk-issues. (line 27) * SUBDATE(): date-and-time-functions. (line 856) * SUBPARTITION BY KEY, known issues: partitioning-limitations. (line 311) * subpartitioning: partitioning-subpartitions. (line 6) * subpartitions: partitioning-subpartitions. (line 6) * subpartitions, known issues: partitioning-limitations. (line 307) * subqueries: subqueries. (line 20) * subqueries, correlated: correlated-subqueries. (line 6) * subqueries, errors: subquery-errors. (line 6) * subqueries, rewriting as joins: rewriting-subqueries. (line 6) * subqueries, with ALL: all-subqueries. (line 6) * subqueries, with ANY, IN, SOME: any-in-some-subqueries. (line 6) * subqueries, with EXISTS: exists-and-not-exists-subqueries. (line 6) * subqueries, with NOT EXISTS: exists-and-not-exists-subqueries. (line 6) * subqueries, with ROW: row-subqueries. (line 6) * subquery: subqueries. (line 20) * subquery optimization: in-subquery-optimization. (line 6) * subquery, restrictions: subquery-restrictions. (line 6) * subselects: subqueries. (line 20) * SUBSTR(): string-functions. (line 632) * SUBSTRING(): string-functions. (line 637) * SUBSTRING_INDEX(): string-functions. (line 670) * SUBTIME(): date-and-time-functions. (line 874) * subtraction (-): arithmetic-functions. (line 62) * suffix option, mysqlhotcopy: mysqlhotcopy. (line 177) * SUM(): group-by-functions. (line 262) * SUM(DISTINCT): group-by-functions. (line 262) * superuser: default-privileges. (line 6) * superuser option, mysqlaccess: mysqlaccess. (line 148) * support, for operating systems: supported-os. (line 6) * suppression, default values: constraint-invalid-data. (line 6) * Sybase compatibility: use. (line 27) * symbolic links <1>: windows-symbolic-links. (line 6) * symbolic links: symbolic-links. (line 12) * symbolic-links option, mysqld: server-options. (line 1917) * symbols-file option, resolve_stack_dump: resolve-stack-dump. (line 29) * SymDifference(): spatial-operators. (line 31) * sync_binlog system variable: replication-options-binary-log. (line 638) * sync_frm system variable: server-system-variables. (line 5274) * synchronization of master and slave, in MySQL Cluster Replication: mysql-cluster-replication-auto-sync. (line 6) * Syncing ndb table schema operation and binlog, thread state: mysql-cluster-thread-states. (line 20) * syntax conventions: manual-conventions. (line 8) * syntax, regular expression: regexp. (line 6) * SYSDATE(): date-and-time-functions. (line 885) * sysdate-is-now option, mysqld: server-options. (line 2100) * syslog option, mysqld_safe: mysqld-safe. (line 228) * syslog-tag option, mysqld_safe: mysqld-safe. (line 235) * system command, mysql: mysql-commands. (line 211) * System lock, thread state: general-thread-states. (line 316) * system optimization: system-optimization. (line 6) * system table, optimizer <1>: select. (line 493) * system table, optimizer: explain-output. (line 89) * system variable, auto_increment_increment: replication-options-master. (line 21) * system variable, auto_increment_offset: replication-options-master. (line 224) * system variable, automatic_sp_privileges: server-system-variables. (line 614) * system variable, back_log: server-system-variables. (line 641) * system variable, basedir: server-system-variables. (line 676) * system variable, binlog_cache_size: replication-options-binary-log. (line 364) * system variable, binlog_direct_non_transactional_updates: replication-options-binary-log. (line 400) * system variable, binlog_format: replication-options-binary-log. (line 455) * system variable, bulk_insert_buffer_size: server-system-variables. (line 713) * system variable, character_set_client: server-system-variables. (line 747) * system variable, character_set_connection: server-system-variables. (line 785) * system variable, character_set_database: server-system-variables. (line 801) * system variable, character_set_filesystem: server-system-variables. (line 840) * system variable, character_set_results: server-system-variables. (line 871) * system variable, character_set_server: server-system-variables. (line 886) * system variable, character_set_system: server-system-variables. (line 905) * system variable, character_sets_dir: server-system-variables. (line 919) * system variable, collation_connection: server-system-variables. (line 938) * system variable, collation_database: server-system-variables. (line 952) * system variable, collation_server: server-system-variables. (line 991) * system variable, completion_type: server-system-variables. (line 1010) * system variable, concurrent_insert: server-system-variables. (line 1049) * system variable, connect_timeout: server-system-variables. (line 1087) * system variable, datadir: server-system-variables. (line 1120) * system variable, date_format: server-system-variables. (line 1141) * system variable, datetime_format: server-system-variables. (line 1145) * system variable, debug: server-system-variables. (line 1149) * system variable, debug_sync: server-system-variables. (line 1201) * system variable, default_week_format: server-system-variables. (line 1239) * system variable, delay_key_write: server-system-variables. (line 1261) * system variable, delayed_insert_limit: server-system-variables. (line 1308) * system variable, delayed_insert_timeout: server-system-variables. (line 1340) * system variable, delayed_queue_size: server-system-variables. (line 1361) * system variable, div_precision_increment: server-system-variables. (line 1393) * system variable, engine_condition_pushdown: server-system-variables. (line 1432) * system variable, event_scheduler: server-system-variables. (line 1478) * system variable, expire_logs_days: server-system-variables. (line 1507) * system variable, flush: server-system-variables. (line 1534) * system variable, flush_time: server-system-variables. (line 1556) * system variable, ft_boolean_syntax: server-system-variables. (line 1606) * system variable, ft_max_word_len: server-system-variables. (line 1643) * system variable, ft_min_word_len: server-system-variables. (line 1668) * system variable, ft_query_expansion_limit: server-system-variables. (line 1694) * system variable, ft_stopword_file: server-system-variables. (line 1715) * system variable, general_log: server-system-variables. (line 1747) * system variable, general_log_file: server-system-variables. (line 1773) * system variable, group_concat_max_len: server-system-variables. (line 1797) * system variable, have_archive: server-system-variables. (line 1827) * system variable, have_blackhole_engine: server-system-variables. (line 1832) * system variable, have_community_features: server-system-variables. (line 1843) * system variable, have_compress: server-system-variables. (line 1837) * system variable, have_crypt: server-system-variables. (line 1850) * system variable, have_csv: server-system-variables. (line 1855) * system variable, have_dynamic_loading: server-system-variables. (line 1863) * system variable, have_example_engine: server-system-variables. (line 1868) * system variable, have_federated_engine: server-system-variables. (line 1873) * system variable, have_geometry: server-system-variables. (line 1878) * system variable, have_innodb: server-system-variables. (line 1882) * system variable, have_isam: server-system-variables. (line 1890) * system variable, have_merge_engine: server-system-variables. (line 1896) * system variable, have_openssl: server-system-variables. (line 1902) * system variable, have_partitioning: server-system-variables. (line 1907) * system variable, have_query_cache: server-system-variables. (line 1916) * system variable, have_raid: server-system-variables. (line 1939) * system variable, have_row_based_replication: server-system-variables. (line 1921) * system variable, have_rtree_keys: server-system-variables. (line 1945) * system variable, have_ssl: server-system-variables. (line 1950) * system variable, have_symlink: server-system-variables. (line 1960) * system variable, hostname: server-system-variables. (line 1967) * system variable, init_connect: server-system-variables. (line 1989) * system variable, init_file: server-system-variables. (line 2030) * system variable, init_slave: replication-options-slave. (line 1217) * system variable, interactive_timeout: server-system-variables. (line 2068) * system variable, join_buffer_size: server-system-variables. (line 2093) * system variable, keep_files_on_create: server-system-variables. (line 2127) * system variable, key_buffer_size: server-system-variables. (line 2162) * system variable, key_cache_age_threshold: server-system-variables. (line 2261) * system variable, key_cache_block_size: server-system-variables. (line 2292) * system variable, key_cache_division_limit: server-system-variables. (line 2313) * system variable, language: server-system-variables. (line 2336) * system variable, large_files_support: server-system-variables. (line 2361) * system variable, large_page_size: server-system-variables. (line 2392) * system variable, large_pages: server-system-variables. (line 2371) * system variable, lc_time_names: server-system-variables. (line 2417) * system variable, license: server-system-variables. (line 2439) * system variable, local_infile: server-system-variables. (line 2453) * system variable, locked_in_memory: server-system-variables. (line 2467) * system variable, log: server-system-variables. (line 2477) * system variable, log_bin: server-system-variables. (line 2485) * system variable, log_bin_trust_function_creators: server-system-variables. (line 2500) * system variable, log_error: server-system-variables. (line 2530) * system variable, log_output: server-system-variables. (line 2549) * system variable, log_queries_not_using_indexes: server-system-variables. (line 2581) * system variable, log_slave_updates: server-system-variables. (line 2601) * system variable, log_slow_queries: server-system-variables. (line 2608) * system variable, log_warnings: server-system-variables. (line 2635) * system variable, long_query_time: server-system-variables. (line 2665) * system variable, low_priority_updates: server-system-variables. (line 2698) * system variable, lower_case_file_system: server-system-variables. (line 2724) * system variable, lower_case_table_names: server-system-variables. (line 2746) * system variable, max_allowed_packet: server-system-variables. (line 2794) * system variable, max_binlog_cache_size: replication-options-binary-log. (line 570) * system variable, max_binlog_size: replication-options-binary-log. (line 607) * system variable, max_connect_errors: server-system-variables. (line 2839) * system variable, max_connections: server-system-variables. (line 2874) * system variable, max_delayed_threads: server-system-variables. (line 2915) * system variable, max_error_count: server-system-variables. (line 2945) * system variable, max_heap_table_size: server-system-variables. (line 2968) * system variable, max_insert_delayed_threads: server-system-variables. (line 3009) * system variable, max_join_size: server-system-variables. (line 3023) * system variable, max_length_for_sort_data: server-system-variables. (line 3063) * system variable, max_long_data_size: server-system-variables. (line 3085) * system variable, max_prepared_stmt_count: server-system-variables. (line 3112) * system variable, max_relay_log_size: server-system-variables. (line 3143) * system variable, max_seeks_for_key: server-system-variables. (line 3172) * system variable, max_sort_length: server-system-variables. (line 3207) * system variable, max_sp_recursion_depth: server-system-variables. (line 3230) * system variable, max_tmp_tables: server-system-variables. (line 3259) * system variable, max_user_connections: server-system-variables. (line 3289) * system variable, max_write_lock_count: server-system-variables. (line 3328) * system variable, min_examined_row_limit: server-system-variables. (line 3357) * system variable, myisam_data_pointer_size: server-system-variables. (line 3386) * system variable, myisam_max_sort_file_size: server-system-variables. (line 3409) * system variable, myisam_mmap_size: server-system-variables. (line 3438) * system variable, myisam_recover_options: server-system-variables. (line 3471) * system variable, myisam_repair_threads: server-system-variables. (line 3481) * system variable, myisam_sort_buffer_size: server-system-variables. (line 3516) * system variable, myisam_stats_method: server-system-variables. (line 3553) * system variable, myisam_use_mmap: server-system-variables. (line 3590) * system variable, named_pipe: server-system-variables. (line 3611) * system variable, net_buffer_length: server-system-variables. (line 3627) * system variable, net_read_timeout: server-system-variables. (line 3662) * system variable, net_retry_count: server-system-variables. (line 3694) * system variable, net_write_timeout: server-system-variables. (line 3733) * system variable, new: server-system-variables. (line 3762) * system variable, old: server-system-variables. (line 3786) * system variable, old_alter_table: server-system-variables. (line 3813) * system variable, old_passwords: server-system-variables. (line 3839) * system variable, one_shot: server-system-variables. (line 3860) * system variable, open_files_limit: server-system-variables. (line 3865) * system variable, optimizer_prune_level: server-system-variables. (line 3890) * system variable, optimizer_search_depth: server-system-variables. (line 3914) * system variable, optimizer_switch: server-system-variables. (line 3943) * system variable, pid_file: server-system-variables. (line 3978) * system variable, plugin_dir: server-system-variables. (line 3998) * system variable, port: server-system-variables. (line 4035) * system variable, preload_buffer_size: server-system-variables. (line 4056) * system variable, prepared_stmt_count: server-system-variables. (line 4077) * system variable, protocol_version: server-system-variables. (line 4101) * system variable, pseudo_thread_id: server-system-variables. (line 4114) * system variable, query_alloc_block_size: server-system-variables. (line 4127) * system variable, query_cache_limit: server-system-variables. (line 4161) * system variable, query_cache_min_res_unit: server-system-variables. (line 4190) * system variable, query_cache_size: server-system-variables. (line 4220) * system variable, query_cache_type: server-system-variables. (line 4258) * system variable, query_cache_wlock_invalidate: server-system-variables. (line 4298) * system variable, query_prealloc_size: server-system-variables. (line 4324) * system variable, range_alloc_block_size: server-system-variables. (line 4378) * system variable, read_buffer_size: server-system-variables. (line 4402) * system variable, read_only: server-system-variables. (line 4434) * system variable, read_rnd_buffer_size: server-system-variables. (line 4503) * system variable, relay_log_index: replication-options-slave. (line 1246) * system variable, relay_log_info_file: replication-options-slave. (line 1267) * system variable, relay_log_purge: server-system-variables. (line 4537) * system variable, relay_log_space_limit: server-system-variables. (line 4557) * system variable, report_host: server-system-variables. (line 4585) * system variable, report_password: server-system-variables. (line 4604) * system variable, report_port: server-system-variables. (line 4625) * system variable, report_user: server-system-variables. (line 4645) * system variable, secure_auth: server-system-variables. (line 4664) * system variable, secure_file_priv: server-system-variables. (line 4693) * system variable, server_id: server-system-variables. (line 4718) * system variable, server_id_bits: mysql-cluster-system-variables. (line 863) * system variable, shared_memory: server-system-variables. (line 4742) * system variable, shared_memory_base_name: server-system-variables. (line 4753) * system variable, skip_external_locking: server-system-variables. (line 4766) * system variable, skip_name_resolve: server-system-variables. (line 4772) * system variable, skip_networking: server-system-variables. (line 4782) * system variable, skip_show_database: server-system-variables. (line 4791) * system variable, slave_compressed_protocol: replication-options-slave. (line 1292) * system variable, slave_exec_mode: replication-options-slave. (line 1312) * system variable, slave_load_tmpdir: replication-options-slave. (line 1345) * system variable, slave_net_timeout: replication-options-slave. (line 1366) * system variable, slave_skip_errors: replication-options-slave. (line 1389) * system variable, slave_transaction_retries: replication-options-slave. (line 1407) * system variable, slave_type_conversions: replication-options-slave. (line 1443) * system variable, slow_launch_time: server-system-variables. (line 4806) * system variable, slow_query_log: server-system-variables. (line 4826) * system variable, slow_query_log_file: server-system-variables. (line 4837) * system variable, socket: server-system-variables. (line 4860) * system variable, sort_buffer_size: server-system-variables. (line 4887) * system variable, sql_mode: server-system-variables. (line 5053) * system variable, sql_select_limit: server-system-variables. (line 5122) * system variable, sql_slave_skip_counter: replication-options-slave. (line 1480) * system variable, ssl_ca: server-system-variables. (line 5158) * system variable, ssl_capath: server-system-variables. (line 5179) * system variable, ssl_cert: server-system-variables. (line 5200) * system variable, ssl_cipher: server-system-variables. (line 5221) * system variable, ssl_key: server-system-variables. (line 5242) * system variable, storage_engine: server-system-variables. (line 5262) * system variable, sync_binlog: replication-options-binary-log. (line 638) * system variable, sync_frm: server-system-variables. (line 5274) * system variable, system_time_zone: server-system-variables. (line 5296) * system variable, table_cache: server-system-variables. (line 5321) * system variable, table_definition_cache: server-system-variables. (line 5347) * system variable, table_lock_wait_timeout: server-system-variables. (line 5383) * system variable, table_open_cache: server-system-variables. (line 5403) * system variable, table_type: server-system-variables. (line 5431) * system variable, thread_cache_size: server-system-variables. (line 5450) * system variable, thread_concurrency: server-system-variables. (line 5483) * system variable, thread_handling: server-system-variables. (line 5507) * system variable, thread_stack: server-system-variables. (line 5528) * system variable, time_format: server-system-variables. (line 5564) * system variable, time_zone: server-system-variables. (line 5568) * system variable, timed_mutexes: server-system-variables. (line 5590) * system variable, tmp_table_size: server-system-variables. (line 5629) * system variable, tmpdir: server-system-variables. (line 5665) * system variable, transaction_alloc_block_size: server-system-variables. (line 5702) * system variable, transaction_prealloc_size: server-system-variables. (line 5756) * system variable, tx_isolation: server-system-variables. (line 5797) * system variable, updatable_views_with_limit: server-system-variables. (line 5856) * system variable, version: server-system-variables. (line 5889) * system variable, version_comment: server-system-variables. (line 5897) * system variable, version_compile_machine: server-system-variables. (line 5912) * system variable, version_compile_os: server-system-variables. (line 5925) * system variable, wait_timeout: server-system-variables. (line 5938) * system variables <1>: show-variables. (line 6) * system variables <2>: using-system-variables. (line 11) * system variables: server-system-variables. (line 6) * system variables, and replication: replication-features-variables. (line 6) * system, privilege: privilege-system. (line 16) * system, security: security. (line 15) * system_time_zone system variable: server-system-variables. (line 5296) * SYSTEM_USER(): information-functions. (line 550) * tab (\t) <1>: load-data. (line 431) * tab (\t): string-syntax. (line 62) * tab option, mysqldump: mysqldump. (line 927) * table aliases: select. (line 160) * table cache: table-cache. (line 6) * table description, myisamchk: myisamchk-table-info. (line 6) * Table Dump, thread command: thread-commands. (line 128) * table is full <1>: full-table. (line 6) * table is full: server-system-variables. (line 700) * Table is full errors, MySQL Cluster: faqs-mysql-cluster. (line 6) * Table lock, thread state: general-thread-states. (line 327) * Table Monitor, InnoDB <1>: innodb-troubleshooting-datadict. (line 57) * Table Monitor, InnoDB: innodb-monitors. (line 12) * table names, case sensitivity: identifier-case-sensitivity. (line 6) * table names, case-sensitivity: extensions-to-ansi. (line 38) * table option, mysql: mysql-command-options. (line 519) * table option, mysqlaccess: mysqlaccess. (line 152) * table scans, avoiding: how-to-avoid-table-scan. (line 6) * table types, choosing: storage-engines. (line 23) * table, changing <1>: alter-table-problems. (line 6) * table, changing: alter-table. (line 12) * table, deleting: drop-table. (line 6) * table, rebuilding: rebuilding-tables. (line 6) * table, repair: rebuilding-tables. (line 6) * table, row size: storage-requirements. (line 24) * table-level locking: internal-locking. (line 6) * table_cache system variable: server-system-variables. (line 5321) * table_definition_cache system variable: server-system-variables. (line 5347) * table_lock_wait_timeout system variable: server-system-variables. (line 5383) * table_open_cache: table-cache. (line 6) * table_open_cache system variable: server-system-variables. (line 5403) * TABLE_PRIVILEGES, INFORMATION_SCHEMA table: table-privileges-table. (line 6) * table_type system variable: server-system-variables. (line 5431) * tables option, mysqlcheck: mysqlcheck. (line 388) * tables option, mysqldump: mysqldump. (line 956) * tables, BLACKHOLE: blackhole-storage-engine. (line 6) * tables, checking: myisamchk-check-options. (line 6) * tables, closing: table-cache. (line 6) * tables, compressed: myisampack. (line 6) * tables, compressed format: compressed-format. (line 6) * tables, const: explain-output. (line 94) * tables, constant: where-optimizations. (line 50) * tables, copying <1>: create-table-select. (line 6) * tables, copying: create-table. (line 1235) * tables, counting rows: counting-rows. (line 6) * tables, creating: creating-tables. (line 6) * tables, CSV: csv-storage-engine. (line 11) * tables, defragment: dynamic-format. (line 16) * tables, defragmenting <1>: optimize-table. (line 6) * tables, defragmenting: myisam-maintenance-schedule. (line 38) * tables, deleting rows: deleting-from-related-tables. (line 6) * tables, displaying: mysqlshow. (line 6) * tables, displaying status: show-table-status. (line 6) * tables, dumping <1>: mysqlhotcopy. (line 6) * tables, dumping: mysqldump. (line 6) * tables, dynamic: dynamic-format. (line 6) * tables, error checking: myisam-check. (line 6) * tables, EXAMPLE: example-storage-engine. (line 6) * tables, FEDERATED: federated-storage-engine. (line 13) * tables, flush: mysqladmin. (line 186) * tables, fragmentation: optimize-table. (line 6) * tables, HEAP: memory-storage-engine. (line 6) * tables, host: request-access. (line 148) * tables, improving performance: data-size. (line 6) * tables, information: myisamchk-table-info. (line 6) * tables, information about: getting-information. (line 6) * TABLES, INFORMATION_SCHEMA table: tables-table. (line 6) * tables, InnoDB: innodb-storage-engine. (line 23) * tables, loading data: loading-tables. (line 6) * tables, maintenance: mysqlcheck. (line 6) * tables, maintenance schedule: myisam-maintenance-schedule. (line 6) * tables, maximum size: table-size-limit. (line 6) * tables, MEMORY: memory-storage-engine. (line 6) * tables, MERGE: merge-storage-engine. (line 11) * tables, merging: merge-storage-engine. (line 11) * tables, multiple: multiple-tables. (line 6) * tables, MyISAM: myisam-storage-engine. (line 13) * tables, names: identifiers. (line 13) * tables, open: table-cache. (line 6) * tables, opening: table-cache. (line 6) * tables, optimizing: myisam-optimization. (line 6) * tables, partitioning: merge-storage-engine. (line 11) * tables, repair: mysqlcheck. (line 6) * tables, repairing: myisam-repair. (line 6) * tables, retrieving data: retrieving-data. (line 18) * tables, selecting columns: selecting-columns. (line 6) * tables, selecting rows: selecting-rows. (line 6) * tables, sorting rows: sorting-rows. (line 6) * tables, symbolic links: symbolic-links-to-tables. (line 6) * tables, system: explain-output. (line 89) * tables, too many: creating-many-tables. (line 6) * tables, unique ID for last row: getting-unique-id. (line 6) * tables, updating: ansi-diff-transactions. (line 6) * Tablespace Monitor, InnoDB <1>: innodb-monitors. (line 12) * Tablespace Monitor, InnoDB <2>: innodb-file-space. (line 48) * Tablespace Monitor, InnoDB: innodb-backup. (line 109) * TAN(): mathematical-functions. (line 558) * tar, problems on Solaris: solaris-installation. (line 11) * tc-heuristic-recover option, mysqld: server-options. (line 2123) * Tcl API: apis-tcl. (line 6) * tcp-ip option, mysqld_multi: mysqld-multi. (line 159) * TCP/IP <1>: windows-testing. (line 6) * TCP/IP: windows-select-server. (line 45) * tee command, mysql: mysql-commands. (line 217) * tee option, mysql: mysql-command-options. (line 525) * temp-pool option, mysqld: server-options. (line 2139) * temporary file, write access: mysql-install-db-problems. (line 70) * temporary files: temporary-files. (line 6) * temporary tables, and replication: replication-features-temptables. (line 6) * temporary tables, internal: internal-temporary-tables. (line 6) * temporary tables, problems: temporary-table-problems. (line 6) * terminal monitor, defined: tutorial. (line 16) * test option, myisampack: myisampack. (line 97) * testing mysqld, mysqltest: mysql-test-suite. (line 6) * testing, connection to the server: connection-access. (line 6) * testing, installation: unix-postinstallation. (line 54) * testing, of MySQL releases: choosing-version. (line 119) * testing, postinstallation: postinstallation. (line 11) * TEXT columns, default values: blob. (line 53) * TEXT columns, indexing <1>: create-table. (line 494) * TEXT columns, indexing: column-indexes. (line 15) * TEXT data type <1>: blob. (line 6) * TEXT data type: string-type-overview. (line 191) * text files, importing <1>: mysqlimport. (line 6) * text files, importing: batch-commands. (line 6) * TEXT, size: storage-requirements. (line 197) * thread cache: connection-threads. (line 6) * thread command, Binlog Dump: thread-commands. (line 8) * thread command, Change user: thread-commands. (line 13) * thread command, Close stmt: thread-commands. (line 17) * thread command, Connect: thread-commands. (line 21) * thread command, Connect Out: thread-commands. (line 25) * thread command, Create DB: thread-commands. (line 29) * thread command, Daemon: thread-commands. (line 33) * thread command, Debug: thread-commands. (line 38) * thread command, Delayed insert: thread-commands. (line 42) * thread command, Drop DB: thread-commands. (line 46) * thread command, Error: thread-commands. (line 50) * thread command, Execute: thread-commands. (line 52) * thread command, Fetch: thread-commands. (line 56) * thread command, Field List: thread-commands. (line 61) * thread command, Init DB: thread-commands. (line 65) * thread command, Kill: thread-commands. (line 69) * thread command, Long Data: thread-commands. (line 73) * thread command, Ping: thread-commands. (line 78) * thread command, Prepare: thread-commands. (line 82) * thread command, Processlist: thread-commands. (line 86) * thread command, Query: thread-commands. (line 90) * thread command, Quit: thread-commands. (line 94) * thread command, Refresh: thread-commands. (line 98) * thread command, Register Slave: thread-commands. (line 103) * thread command, Reset stmt: thread-commands. (line 107) * thread command, Set option: thread-commands. (line 111) * thread command, Shutdown: thread-commands. (line 116) * thread command, Sleep: thread-commands. (line 120) * thread command, Statistics: thread-commands. (line 124) * thread command, Table Dump: thread-commands. (line 128) * thread command, Time: thread-commands. (line 132) * thread commands: thread-commands. (line 6) * thread state, After create: general-thread-states. (line 11) * thread state, allocating local table: delayed-insert-thread-states. (line 17) * thread state, Analyzing: general-thread-states. (line 18) * thread state, Changing master: slave-connection-thread-states. (line 9) * thread state, Checking master version: slave-io-thread-states. (line 20) * thread state, checking permissions: general-thread-states. (line 23) * thread state, checking privileges on cached query: query-cache-thread-states. (line 9) * thread state, checking query cache for query: query-cache-thread-states. (line 14) * thread state, Checking table: general-thread-states. (line 28) * thread state, cleaning up: general-thread-states. (line 32) * thread state, Clearing: event-scheduler-thread-states. (line 10) * thread state, closing tables: general-thread-states. (line 37) * thread state, Committing events to binlog: mysql-cluster-thread-states. (line 6) * thread state, Connecting to master: slave-io-thread-states. (line 16) * thread state, converting HEAP to MyISAM: general-thread-states. (line 44) * thread state, copy to tmp table: general-thread-states. (line 49) * thread state, Copying to group table: general-thread-states. (line 55) * thread state, Copying to tmp table: general-thread-states. (line 60) * thread state, Copying to tmp table on disk: general-thread-states. (line 64) * thread state, Creating delayed handler: delayed-insert-thread-states. (line 22) * thread state, Creating index: general-thread-states. (line 72) * thread state, Creating sort index: general-thread-states. (line 77) * thread state, creating table: general-thread-states. (line 82) * thread state, Creating table from master dump: slave-connection-thread-states. (line 14) * thread state, Creating tmp table: general-thread-states. (line 87) * thread state, deleting from main table: general-thread-states. (line 94) * thread state, deleting from reference tables: general-thread-states. (line 100) * thread state, discard_or_import_tablespace: general-thread-states. (line 105) * thread state, end: general-thread-states. (line 110) * thread state, executing: general-thread-states. (line 117) * thread state, Execution of init_command: general-thread-states. (line 121) * thread state, Finished reading one binlog; switching to next binlog: master-thread-states. (line 17) * thread state, Flushing tables: general-thread-states. (line 132) * thread state, freeing items: general-thread-states. (line 126) * thread state, FULLTEXT initialization: general-thread-states. (line 137) * thread state, got handler lock: delayed-insert-thread-states. (line 26) * thread state, got old table: delayed-insert-thread-states. (line 32) * thread state, Has read all relay log; waiting for the slave I/O thread to update it: slave-sql-thread-states. (line 18) * thread state, Has sent all binlog to slave; waiting for binlog to be updated: master-thread-states. (line 22) * thread state, init: general-thread-states. (line 142) * thread state, Initialized: event-scheduler-thread-states. (line 15) * thread state, insert: delayed-insert-thread-states. (line 76) * thread state, invalidating query cache entries: query-cache-thread-states. (line 19) * thread state, Killed: general-thread-states. (line 158) * thread state, Killing slave: slave-connection-thread-states. (line 21) * thread state, Locked: general-thread-states. (line 167) * thread state, logging slow query: general-thread-states. (line 171) * thread state, login: general-thread-states. (line 180) * thread state, Making temp file: slave-sql-thread-states. (line 25) * thread state, manage keys: general-thread-states. (line 185) * thread state, NULL: general-thread-states. (line 175) * thread state, Opening master dump table: slave-connection-thread-states. (line 25) * thread state, Opening mysql.ndb_apply_status: mysql-cluster-thread-states. (line 8) * thread state, Opening table: general-thread-states. (line 189) * thread state, Opening tables: general-thread-states. (line 189) * thread state, optimizing: general-thread-states. (line 198) * thread state, preparing: general-thread-states. (line 202) * thread state, Processing events: mysql-cluster-thread-states. (line 10) * thread state, Processing events from schema table: mysql-cluster-thread-states. (line 14) * thread state, Purging old relay logs: general-thread-states. (line 206) * thread state, query end: general-thread-states. (line 210) * thread state, Queueing master event to the relay log: slave-io-thread-states. (line 57) * thread state, Reading event from the relay log: slave-sql-thread-states. (line 13) * thread state, Reading from net: general-thread-states. (line 215) * thread state, Reading master dump table data: slave-connection-thread-states. (line 29) * thread state, Rebuilding the index on master dump table: slave-connection-thread-states. (line 33) * thread state, Reconnecting after a failed binlog dump request: slave-io-thread-states. (line 45) * thread state, Reconnecting after a failed master event read: slave-io-thread-states. (line 70) * thread state, Registering slave on master: slave-io-thread-states. (line 25) * thread state, Removing duplicates: general-thread-states. (line 219) * thread state, removing tmp table: general-thread-states. (line 226) * thread state, rename: general-thread-states. (line 232) * thread state, rename result table: general-thread-states. (line 236) * thread state, Reopen tables: general-thread-states. (line 242) * thread state, Repair by sorting: general-thread-states. (line 248) * thread state, Repair done: general-thread-states. (line 252) * thread state, Repair with keycache: general-thread-states. (line 257) * thread state, Requesting binlog dump: slave-io-thread-states. (line 30) * thread state, reschedule: delayed-insert-thread-states. (line 80) * thread state, Rolling back: general-thread-states. (line 262) * thread state, Saving state: general-thread-states. (line 266) * thread state, Searching rows for update: general-thread-states. (line 273) * thread state, Sending binlog event to slave: master-thread-states. (line 11) * thread state, sending cached result to client: query-cache-thread-states. (line 24) * thread state, setup: general-thread-states. (line 287) * thread state, Shutting down: mysql-cluster-thread-states. (line 18) * thread state, Sorting for group: general-thread-states. (line 292) * thread state, Sorting for order: general-thread-states. (line 296) * thread state, Sorting index: general-thread-states. (line 300) * thread state, Sorting result: general-thread-states. (line 305) * thread state, starting slave: slave-connection-thread-states. (line 37) * thread state, statistics: general-thread-states. (line 310) * thread state, storing result in query cache: query-cache-thread-states. (line 29) * thread state, storing row into queue: delayed-insert-thread-states. (line 39) * thread state, Syncing ndb table schema operation and binlog: mysql-cluster-thread-states. (line 20) * thread state, System lock: general-thread-states. (line 316) * thread state, Table lock: general-thread-states. (line 327) * thread state, update: delayed-insert-thread-states. (line 44) * thread state, Updating: general-thread-states. (line 333) * thread state, updating main table: general-thread-states. (line 337) * thread state, updating reference tables: general-thread-states. (line 343) * thread state, upgrading lock: delayed-insert-thread-states. (line 85) * thread state, User lock: general-thread-states. (line 348) * thread state, User sleep: general-thread-states. (line 355) * thread state, waiting for delay_list: delayed-insert-thread-states. (line 48) * thread state, Waiting for event from ndbcluster: mysql-cluster-thread-states. (line 25) * thread state, Waiting for first event from ndbcluster: mysql-cluster-thread-states. (line 30) * thread state, waiting for handler insert: delayed-insert-thread-states. (line 55) * thread state, waiting for handler lock: delayed-insert-thread-states. (line 60) * thread state, waiting for handler open: delayed-insert-thread-states. (line 66) * thread state, Waiting for INSERT: delayed-insert-thread-states. (line 90) * thread state, Waiting for master to send event: slave-io-thread-states. (line 49) * thread state, Waiting for master update: slave-io-thread-states. (line 12) * thread state, Waiting for ndbcluster binlog update to reach current position: mysql-cluster-thread-states. (line 32) * thread state, Waiting for ndbcluster to start: mysql-cluster-thread-states. (line 34) * thread state, Waiting for next activation: event-scheduler-thread-states. (line 20) * thread state, Waiting for release of readlock: general-thread-states. (line 359) * thread state, Waiting for scheduler to stop: event-scheduler-thread-states. (line 25) * thread state, Waiting for schema epoch: mysql-cluster-thread-states. (line 36) * thread state, Waiting for slave mutex on exit <1>: slave-sql-thread-states. (line 31) * thread state, Waiting for slave mutex on exit: slave-io-thread-states. (line 84) * thread state, Waiting for table: general-thread-states. (line 365) * thread state, Waiting for tables: general-thread-states. (line 365) * thread state, Waiting for the next event in relay log: slave-sql-thread-states. (line 9) * thread state, Waiting for the slave SQL thread to free enough relay log space: slave-io-thread-states. (line 76) * thread state, Waiting on cond: general-thread-states. (line 379) * thread state, Waiting on empty queue: event-scheduler-thread-states. (line 30) * thread state, Waiting to finalize termination: master-thread-states. (line 29) * thread state, Waiting to get readlock: general-thread-states. (line 384) * thread state, Waiting to reconnect after a failed binlog dump request: slave-io-thread-states. (line 37) * thread state, Waiting to reconnect after a failed master event read: slave-io-thread-states. (line 62) * thread state, Writing to net: general-thread-states. (line 390) * thread states, delayed inserts: delayed-insert-thread-states. (line 6) * thread states, event scheduler: event-scheduler-thread-states. (line 6) * thread states, general: general-thread-states. (line 6) * thread states, MySQL Cluster: mysql-cluster-thread-states. (line 6) * thread states, query cache: query-cache-thread-states. (line 6) * thread states, replication master: master-thread-states. (line 6) * thread states, replication slave <1>: slave-connection-thread-states. (line 6) * thread states, replication slave <2>: slave-sql-thread-states. (line 6) * thread states, replication slave: slave-io-thread-states. (line 6) * thread support: supported-os. (line 6) * thread_cache_size system variable: server-system-variables. (line 5450) * thread_concurrency system variable: server-system-variables. (line 5483) * thread_handling system variable: server-system-variables. (line 5507) * thread_stack system variable: server-system-variables. (line 5528) * threaded clients: threaded-clients. (line 6) * ThreadPool: mysql-cluster-ndbd-definition. (line 3411) * threads <1>: mysql-internals. (line 11) * threads <2>: show-processlist. (line 6) * threads: mysqladmin. (line 168) * threads, display: show-processlist. (line 6) * threads, monitoring <1>: processlist-table. (line 6) * threads, monitoring: show-processlist. (line 6) * TIME data type <1>: time. (line 6) * TIME data type: date-and-time-type-overview. (line 63) * time representation, Event Scheduler: events-metadata. (line 21) * time types: storage-requirements. (line 125) * time values: date-and-time-values. (line 6) * time zone problems: timezone-problems. (line 6) * time zone tables: mysql-tzinfo-to-sql. (line 6) * time zones, and replication: replication-features-timezone. (line 6) * time zones, leap seconds: time-zone-leap-seconds. (line 6) * time zones, support: time-zone-support. (line 11) * time zones, upgrading: time-zone-upgrades. (line 6) * TIME(): date-and-time-functions. (line 932) * Time, thread command: thread-commands. (line 132) * time_format system variable: server-system-variables. (line 5564) * TIME_FORMAT(): date-and-time-functions. (line 1015) * TIME_TO_SEC(): date-and-time-functions. (line 1030) * time_zone system variable: server-system-variables. (line 5568) * TimeBetweenEpochs: mysql-cluster-ndbd-definition. (line 2127) * TimeBetweenEpochsTimeout: mysql-cluster-ndbd-definition. (line 2155) * TimeBetweenGlobalCheckpoints: mysql-cluster-ndbd-definition. (line 2095) * TimeBetweenInactiveTransactionAbortCheck: mysql-cluster-ndbd-definition. (line 2261) * TimeBetweenLocalCheckpoints: mysql-cluster-ndbd-definition. (line 2065) * TimeBetweenWatchDogCheck: mysql-cluster-ndbd-definition. (line 1769) * TimeBetweenWatchDogCheckInitial: mysql-cluster-ndbd-definition. (line 1793) * timed_mutexes system variable: server-system-variables. (line 5590) * TIMEDIFF(): date-and-time-functions. (line 946) * timeout <1>: insert-delayed. (line 128) * timeout <2>: miscellaneous-functions. (line 42) * timeout: server-system-variables. (line 1087) * timeout option, ndb_waiter: mysql-cluster-programs-ndb-waiter. (line 55) * timeout, connect_timeout variable <1>: mysqladmin. (line 446) * timeout, connect_timeout variable: mysql-command-options. (line 611) * timeout, shutdown_timeout variable: mysqladmin. (line 451) * timeouts (replication): replication-features-timeout. (line 6) * TIMESTAMP data type <1>: datetime. (line 10) * TIMESTAMP data type: date-and-time-type-overview. (line 31) * timestamp session variable: server-system-variables. (line 5615) * TIMESTAMP(): date-and-time-functions. (line 959) * TIMESTAMP, and logs: upgrading-from-previous-series. (line 737) * TIMESTAMP, and NULL values: problems-with-null. (line 71) * TIMESTAMP, and replication <1>: replication-features-timestamp. (line 6) * TIMESTAMP, and replication <2>: replication-features-auto-increment. (line 6) * TIMESTAMP, and replication: upgrading-from-previous-series. (line 737) * TIMESTAMPADD(): date-and-time-functions. (line 971) * TIMESTAMPDIFF(): date-and-time-functions. (line 992) * timezone option, mysqld_safe: mysqld-safe. (line 244) * TINYBLOB data type: string-type-overview. (line 165) * TINYINT data type: numeric-type-overview. (line 40) * TINYTEXT data type: string-type-overview. (line 172) * tips, optimization: miscellaneous-optimization-tips. (line 6) * tmp_table_size system variable: server-system-variables. (line 5629) * TMPDIR environment variable <1>: temporary-files. (line 6) * TMPDIR environment variable <2>: programs-overview. (line 317) * TMPDIR environment variable <3>: environment-variables. (line 18) * TMPDIR environment variable: mysql-install-db-problems. (line 84) * tmpdir option, myisamchk: myisamchk-repair-options. (line 118) * tmpdir option, myisampack: myisampack. (line 101) * tmpdir option, mysql_upgrade: mysql-upgrade. (line 147) * tmpdir option, mysqld: server-options. (line 2184) * tmpdir option, mysqlhotcopy: mysqlhotcopy. (line 181) * tmpdir system variable: server-system-variables. (line 5665) * to-last-log option, mysqlbinlog: mysqlbinlog. (line 509) * TO_DAYS(): date-and-time-functions. (line 1039) * TODO, symlinks: symbolic-links-to-tables. (line 73) * tools, command-line: mysql. (line 15) * tools, list of: tools-used-to-create-mysql. (line 6) * tools, mysqld_multi: mysqld-multi. (line 6) * tools, mysqld_safe: mysqld-safe. (line 6) * TotalSendBufferMemory, API and SQL nodes: mysql-cluster-api-definition. (line 250) * TotalSendBufferMemory, data nodes: mysql-cluster-ndbd-definition. (line 3803) * TotalSendBufferMemory, management nodes: mysql-cluster-mgm-definition. (line 276) * Touches(): functions-that-test-spatial-relationships-between-geometries. (line 60) * trace DBI method: using-gdb-on-mysqld. (line 89) * trace files (MySQL Cluster): mysql-cluster-programs-ndbd. (line 390) * trace files, ndbmtd: mysql-cluster-programs-ndbmtd. (line 66) * TRADITIONAL SQL mode: server-sql-mode. (line 72) * transaction isolation level: set-transaction. (line 6) * transaction isolation level, READ COMMITTED: set-transaction. (line 80) * transaction isolation level, READ UNCOMMITTED: set-transaction. (line 72) * transaction isolation level, REPEATABLE READ: set-transaction. (line 115) * transaction isolation level, SERIALIZABLE: set-transaction. (line 137) * transaction-isolation option, mysqld: server-options. (line 2159) * transaction-safe tables <1>: innodb-storage-engine. (line 23) * transaction-safe tables: ansi-diff-transactions. (line 6) * transaction_alloc_block_size system variable: server-system-variables. (line 5702) * transaction_allow_batching session variable (MySQL Cluster): server-system-variables. (line 5735) * transaction_prealloc_size system variable: server-system-variables. (line 5756) * transactional option, ndb_delete_all: mysql-cluster-programs-ndb-delete-all. (line 21) * TransactionBufferMemory: mysql-cluster-ndbd-definition. (line 832) * TransactionDeadlockDetectionTimeout: mysql-cluster-ndbd-definition. (line 2299) * TransactionInactiveTimeout: mysql-cluster-ndbd-definition. (line 2279) * transactions, and replication <1>: replication-features-transactions. (line 6) * transactions, and replication: replication-features-timeout. (line 6) * transactions, support <1>: innodb-storage-engine. (line 23) * transactions, support: ansi-diff-transactions. (line 6) * Translators, list of: documenters-translators. (line 6) * transporters, ndbinfo table: mysql-cluster-ndbinfo-transporters. (line 6) * trigger, creating: create-trigger. (line 6) * trigger, dropping: drop-trigger. (line 6) * trigger, restrictions: stored-program-restrictions. (line 6) * triggers <1>: triggers. (line 11) * triggers <2>: stored-programs-views. (line 16) * triggers: show-triggers. (line 6) * triggers option, mysqldump: mysqldump. (line 962) * triggers, and INSERT DELAYED: insert. (line 230) * triggers, and replication <1>: replication-features-triggers. (line 6) * triggers, and replication: replication-features-invoked. (line 6) * TRIGGERS, INFORMATION_SCHEMA table: triggers-table. (line 6) * triggers, LAST_INSERT_ID(): stored-routines-last-insert-id. (line 6) * triggers, metadata: trigger-metadata. (line 6) * TRIM(): string-functions. (line 686) * troubleshooting, FreeBSD: compilation-problems. (line 133) * troubleshooting, Solaris: compilation-problems. (line 133) * TRUE <1>: boolean-values. (line 6) * TRUE: number-syntax. (line 6) * TRUE, testing for: comparison-operators. (line 130) * TRUNCATE TABLE: truncate-table. (line 6) * TRUNCATE TABLE, and MySQL Cluster: mysql-cluster-limitations-limits. (line 9) * TRUNCATE TABLE, and replication: replication-features-truncate. (line 6) * TRUNCATE(): mathematical-functions. (line 567) * tupscan option, ndb_select_all: mysql-cluster-programs-ndb-select-all. (line 73) * tutorial: tutorial. (line 16) * TwoPassInitialNodeRestartCopy: mysql-cluster-ndbd-definition. (line 3311) * tx_isolation system variable: server-system-variables. (line 5797) * type codes, C prepared statement API: c-api-prepared-statement-type-codes. (line 6) * type conversions <1>: comparison-operators. (line 38) * type conversions: type-conversion. (line 6) * type option, mysql_convert_table_format: mysql-convert-table-format. (line 54) * type option, ndb_config: mysql-cluster-programs-ndb-config. (line 183) * type option, ndb_show_tables: mysql-cluster-programs-ndb-show-tables. (line 54) * types, column: data-types. (line 30) * types, columns: choosing-types. (line 6) * types, data: data-types. (line 30) * types, date: storage-requirements. (line 125) * types, Date and Time: date-and-time-types. (line 13) * types, numeric: storage-requirements. (line 83) * types, of tables: storage-engines. (line 23) * types, portability: other-vendor-data-types. (line 6) * types, string: storage-requirements. (line 154) * types, strings: string-types. (line 14) * types, time: storage-requirements. (line 125) * typographical conventions: manual-conventions. (line 8) * TZ environment variable <1>: timezone-problems. (line 6) * TZ environment variable: environment-variables. (line 18) * tz-utc option, mysqldump: mysqldump. (line 967) * UCASE(): string-functions. (line 705) * UCS-2: charset. (line 22) * ucs2 character set: charset-unicode-ucs2. (line 6) * UDFs <1>: drop-function-udf. (line 6) * UDFs: create-function-udf. (line 6) * UDFs, compiling: udf-compiling. (line 6) * UDFs, defined: adding-functions. (line 12) * UDFs, return values: udf-return-values. (line 6) * ulimit: not-enough-file-handles. (line 33) * UMASK environment variable <1>: file-permissions. (line 6) * UMASK environment variable: environment-variables. (line 18) * UMASK_DIR environment variable <1>: file-permissions. (line 20) * UMASK_DIR environment variable: environment-variables. (line 18) * unary minus (-): arithmetic-functions. (line 69) * unbuffered option, mysql: mysql-command-options. (line 531) * UNCOMPRESS(): encryption-functions. (line 348) * UNCOMPRESSED_LENGTH(): encryption-functions. (line 361) * UndoDataBuffer: mysql-cluster-ndbd-definition. (line 2668) * UndoIndexBuffer: mysql-cluster-ndbd-definition. (line 2623) * UNHEX(): string-functions. (line 709) * Unicode: charset. (line 22) * Unicode Collation Algorithm: charset-unicode-sets. (line 69) * UNINSTALL PLUGIN: uninstall-plugin. (line 6) * uninstalling plugins <1>: uninstall-plugin. (line 6) * uninstalling plugins: server-plugin-loading. (line 6) * UNION <1>: union. (line 6) * UNION: searching-on-two-keys. (line 6) * Union(): spatial-operators. (line 36) * UNIQUE: alter-table. (line 332) * unique ID: getting-unique-id. (line 6) * unique key, constraint: constraint-primary-key. (line 6) * unique keys, and partitioning keys: partitioning-limitations-partitioning-keys-unique-keys. (line 6) * unique_checks session variable: server-system-variables. (line 5833) * unique_subquery join type, optimizer: explain-output. (line 180) * Unix <1>: connector-net. (line 18) * Unix: connector-odbc. (line 17) * Unix, compiling clients on: building-clients. (line 25) * UNIX_TIMESTAMP(): date-and-time-functions. (line 1096) * UNKNOWN, testing for: comparison-operators. (line 130) * unloading, tables: retrieving-data. (line 18) * UNLOCK TABLES: lock-tables. (line 12) * unnamed views: from-clause-subqueries. (line 6) * unpack option, myisamchk: myisamchk-repair-options. (line 128) * unqualified option, ndb_show_tables: mysql-cluster-programs-ndb-show-tables. (line 68) * unsafe statement (replication), defined: replication-rbr-safe-unsafe. (line 6) * unsafe statements (replication): replication-rbr-safe-unsafe. (line 40) * UNSIGNED <1>: numeric-types. (line 6) * UNSIGNED: numeric-type-overview. (line 6) * UNTIL: repeat-statement. (line 6) * updatable views: view-updatability. (line 6) * updatable_views_with_limit system variable: server-system-variables. (line 5856) * UPDATE <1>: update. (line 6) * UPDATE: ansi-diff-update. (line 6) * update, thread state: delayed-insert-thread-states. (line 44) * update-state option, myisamchk: myisamchk-check-options. (line 60) * UpdateXML(): xml-functions. (line 275) * updating main table, thread state: general-thread-states. (line 337) * updating reference tables, thread state: general-thread-states. (line 343) * updating, releases of MySQL: many-versions. (line 6) * updating, tables: ansi-diff-transactions. (line 6) * Updating, thread state: general-thread-states. (line 333) * upgrades and downgrades (MySQL Cluster), compatibility between versions: mysql-cluster-upgrade-downgrade. (line 12) * upgrades, MySQL Cluster <1>: mysql-cluster-rolling-restart. (line 6) * upgrades, MySQL Cluster: mysql-cluster-upgrade-downgrade. (line 12) * upgrading <1>: upgrading. (line 10) * upgrading: upgrading-downgrading. (line 14) * upgrading lock, thread state: delayed-insert-thread-states. (line 85) * upgrading MySQL: mysql-upgrade. (line 6) * upgrading, different architecture: copying-databases. (line 6) * upgrading, grant tables: mysql-fix-privilege-tables. (line 6) * upgrading, to ¤t-series;: upgrading-from-previous-series. (line 6) * UPPER(): string-functions. (line 752) * uptime: mysqladmin. (line 164) * URLs for downloading MySQL: getting-mysql. (line 6) * usage option, ndb_config: mysql-cluster-programs-ndb-config. (line 48) * USE: use. (line 6) * use command, mysql: mysql-commands. (line 231) * USE INDEX: index-hints. (line 6) * USE KEY: index-hints. (line 6) * use-frm option, mysqlcheck: mysqlcheck. (line 393) * use-manager option, mysql.server: mysql-server. (line 63) * use-mysqld_safe option, mysql.server: mysql-server. (line 58) * use-threads option, mysqlimport: mysqlimport. (line 295) * use-threads option, mysqlslap: mysqlslap. (line 477) * useHexFormat option, ndb_select_all: mysql-cluster-programs-ndb-select-all. (line 43) * user accounts, creating: create-user. (line 6) * user accounts, renaming: rename-user. (line 6) * user accounts, resource limits <1>: grant. (line 460) * user accounts, resource limits <2>: user-resources. (line 6) * user accounts, resource limits: server-system-variables. (line 3289) * USER environment variable <1>: connecting. (line 231) * USER environment variable: environment-variables. (line 18) * User lock, thread state: general-thread-states. (line 348) * user names, and passwords: user-names. (line 6) * user option: connecting. (line 210) * user option, mysql: mysql-command-options. (line 535) * user option, mysql.server: mysql-server. (line 67) * user option, mysql_convert_table_format: mysql-convert-table-format. (line 59) * user option, mysql_install_db: mysql-install-db. (line 82) * user option, mysql_setpermission: mysql-setpermission. (line 55) * user option, mysql_upgrade: mysql-upgrade. (line 152) * user option, mysqlaccess: mysqlaccess. (line 156) * user option, mysqladmin: mysqladmin. (line 420) * user option, mysqlbinlog: mysqlbinlog. (line 517) * user option, mysqlcheck: mysqlcheck. (line 399) * user option, mysqld: server-options. (line 2218) * user option, mysqld_multi: mysqld-multi. (line 167) * user option, mysqld_safe: mysqld-safe. (line 250) * user option, mysqldump: mysqldump. (line 981) * user option, mysqlhotcopy: mysqlhotcopy. (line 185) * user option, mysqlimport: mysqlimport. (line 291) * user option, mysqlmanager: instance-manager-command-options. (line 224) * user option, mysqlshow: mysqlshow. (line 216) * user option, mysqlslap: mysqlslap. (line 484) * user privileges, adding: adding-users. (line 6) * user privileges, deleting <1>: drop-user. (line 6) * user privileges, deleting: removing-users. (line 6) * user privileges, dropping <1>: drop-user. (line 6) * user privileges, dropping: removing-users. (line 6) * User sleep, thread state: general-thread-states. (line 355) * user table, sorting: connection-access. (line 120) * user variables: user-variables. (line 6) * user variables, and replication: replication-features-variables. (line 6) * USER(): information-functions. (line 554) * User-defined functions <1>: drop-function-udf. (line 6) * User-defined functions: create-function-udf. (line 6) * user-defined functions, adding <1>: adding-udf. (line 15) * user-defined functions, adding: adding-functions. (line 12) * USER_PRIVILEGES, INFORMATION_SCHEMA table: user-privileges-table. (line 6) * username option, mysqlmanager: instance-manager-command-options. (line 235) * users, adding: unix-postinstallation. (line 371) * users, deleting <1>: drop-user. (line 6) * users, deleting: removing-users. (line 6) * users, root: default-privileges. (line 6) * using multiple disks to start data: windows-symbolic-links. (line 6) * using MySQL Cluster programs: mysql-cluster-programs. (line 32) * UTC_DATE(): date-and-time-functions. (line 1154) * UTC_TIME(): date-and-time-functions. (line 1163) * UTC_TIMESTAMP(): date-and-time-functions. (line 1172) * UTF-8: charset. (line 22) * utf8 character set: charset-unicode-utf8. (line 6) * utilities, program-development: programs-overview. (line 256) * utility programs: programs-overview. (line 165) * UUID(): miscellaneous-functions. (line 226) * UUID_SHORT(): miscellaneous-functions. (line 275) * valid numbers, examples: number-syntax. (line 6) * VALUES(): miscellaneous-functions. (line 310) * VAR_POP(): group-by-functions. (line 270) * VAR_SAMP(): group-by-functions. (line 279) * VARBINARY data type <1>: binary-varbinary. (line 6) * VARBINARY data type: string-type-overview. (line 158) * VARCHAR data type <1>: string-types. (line 14) * VARCHAR data type: string-type-overview. (line 121) * VARCHAR, size: storage-requirements. (line 197) * VARCHARACTER data type: string-type-overview. (line 121) * variables, and replication: replication-features-variables. (line 6) * variables, environment: programs-overview. (line 314) * variables, mysqld: server-parameters. (line 11) * variables, server: show-variables. (line 6) * variables, status <1>: show-status. (line 6) * variables, status: server-status-variables. (line 6) * variables, system <1>: show-variables. (line 6) * variables, system <2>: using-system-variables. (line 11) * variables, system: server-system-variables. (line 6) * variables, user: user-variables. (line 6) * VARIANCE(): group-by-functions. (line 286) * verbose option, my_print_defaults: my-print-defaults. (line 57) * verbose option, myisam_ftdump: myisam-ftdump. (line 79) * verbose option, myisamchk: myisamchk-general-options. (line 32) * verbose option, myisampack: myisampack. (line 106) * verbose option, mysql: mysql-command-options. (line 539) * verbose option, mysql_convert_table_format: mysql-convert-table-format. (line 63) * verbose option, mysql_install_db: mysql-install-db. (line 91) * verbose option, mysql_upgrade: mysql-upgrade. (line 157) * verbose option, mysql_waitpid: mysql-waitpid. (line 31) * verbose option, mysqladmin: mysqladmin. (line 424) * verbose option, mysqlbinlog: mysqlbinlog. (line 521) * verbose option, mysqlcheck: mysqlcheck. (line 403) * verbose option, mysqld: server-options. (line 2253) * verbose option, mysqld_multi: mysqld-multi. (line 172) * verbose option, mysqldump: mysqldump. (line 985) * verbose option, mysqldumpslow: mysqldumpslow. (line 103) * verbose option, mysqlimport: mysqlimport. (line 300) * verbose option, mysqlshow: mysqlshow. (line 220) * verbose option, mysqlslap: mysqlslap. (line 488) * verbose option, perror: perror. (line 52) * version option, comp_err: comp-err. (line 71) * version option, my_print_defaults: my-print-defaults. (line 61) * version option, myisamchk: myisamchk-general-options. (line 38) * version option, myisampack: myisampack. (line 111) * version option, mysql: mysql-command-options. (line 546) * version option, mysql_config: mysql-config. (line 52) * version option, mysql_convert_table_format: mysql-convert-table-format. (line 67) * version option, mysql_waitpid: mysql-waitpid. (line 36) * version option, mysqlaccess: mysqlaccess. (line 160) * version option, mysqladmin: mysqladmin. (line 428) * version option, mysqlbinlog: mysqlbinlog. (line 532) * version option, mysqlcheck: mysqlcheck. (line 408) * version option, mysqld: server-options. (line 2257) * version option, mysqld_multi: mysqld-multi. (line 176) * version option, mysqldump: mysqldump. (line 989) * version option, mysqlimport: mysqlimport. (line 304) * version option, mysqlmanager: instance-manager-command-options. (line 240) * version option, mysqlshow: mysqlshow. (line 226) * version option, mysqlslap: mysqlslap. (line 494) * version option, ndb_config: mysql-cluster-programs-ndb-config. (line 59) * version option, perror: perror. (line 57) * version option, resolve_stack_dump: resolve-stack-dump. (line 33) * version option, resolveip: resolveip. (line 23) * version system variable: server-system-variables. (line 5889) * VERSION(): information-functions. (line 571) * version, choosing: which-version. (line 18) * version, latest: getting-mysql. (line 6) * version_comment system variable: server-system-variables. (line 5897) * version_compile_machine system variable: server-system-variables. (line 5912) * version_compile_os system variable: server-system-variables. (line 5925) * vertical option, mysql: mysql-command-options. (line 550) * vertical option, mysqladmin: mysqladmin. (line 432) * Vietnamese: faqs-cjk. (line 6) * view, restrictions: view-restrictions. (line 6) * views <1>: views. (line 13) * views <2>: stored-programs-views. (line 16) * views: create-view. (line 6) * views, algorithms: view-algorithms. (line 6) * views, and replication: replication-features-views. (line 6) * VIEWS, INFORMATION_SCHEMA table: views-table. (line 6) * Views, limitations: view-restrictions. (line 111) * views, metadata: view-metadata. (line 6) * Views, privileges: view-restrictions. (line 111) * Views, problems: view-restrictions. (line 111) * views, updatable <1>: view-updatability. (line 6) * views, updatable: create-view. (line 6) * virtual memory, problems while compiling: compilation-problems. (line 37) * Vision: connector-odbc-usagenotes-apptips-vision. (line 6) * Visual Objects: connector-odbc-usagenotes-apptips-microsoft-visualobjects. (line 6) * Visual Studio: windows-source-build. (line 6) * WAIT COMPLETED (START BACKUP command): mysql-cluster-backup-using-management-client. (line 59) * wait option, myisamchk: myisamchk-general-options. (line 42) * wait option, myisampack: myisampack. (line 115) * wait option, mysql: mysql-command-options. (line 556) * wait option, mysqladmin: mysqladmin. (line 437) * WAIT STARTED (START BACKUP command): mysql-cluster-backup-using-management-client. (line 51) * wait-nodes option, ndb_waiter: mysql-cluster-programs-ndb-waiter. (line 79) * wait-timeout option, mysqlmanager: instance-manager-command-options. (line 244) * wait_timeout system variable: server-system-variables. (line 5938) * waiting for delay_list, thread state: delayed-insert-thread-states. (line 48) * Waiting for event from ndbcluster, thread state: mysql-cluster-thread-states. (line 25) * Waiting for first event from ndbcluster, thread state: mysql-cluster-thread-states. (line 30) * waiting for handler insert, thread state: delayed-insert-thread-states. (line 55) * waiting for handler lock, thread state: delayed-insert-thread-states. (line 60) * waiting for handler open, thread state: delayed-insert-thread-states. (line 66) * Waiting for INSERT, thread state: delayed-insert-thread-states. (line 90) * Waiting for master to send event, thread state: slave-io-thread-states. (line 49) * Waiting for master update, thread state: slave-io-thread-states. (line 12) * Waiting for ndbcluster binlog update to reach current position, thread state: mysql-cluster-thread-states. (line 32) * Waiting for ndbcluster to start, thread state: mysql-cluster-thread-states. (line 34) * Waiting for next activation, thread state: event-scheduler-thread-states. (line 20) * Waiting for release of readlock, thread state: general-thread-states. (line 359) * Waiting for scheduler to stop, thread state: event-scheduler-thread-states. (line 25) * Waiting for schema epoch, thread state: mysql-cluster-thread-states. (line 36) * Waiting for slave mutex on exit, thread state <1>: slave-sql-thread-states. (line 31) * Waiting for slave mutex on exit, thread state: slave-io-thread-states. (line 84) * Waiting for table, thread state: general-thread-states. (line 365) * Waiting for tables, thread state: general-thread-states. (line 365) * Waiting for the next event in relay log, thread state: slave-sql-thread-states. (line 9) * Waiting for the slave SQL thread to free enough relay log space, thread state: slave-io-thread-states. (line 76) * Waiting on cond, thread state: general-thread-states. (line 379) * Waiting on empty queue, thread state: event-scheduler-thread-states. (line 30) * Waiting to finalize termination, thread state: master-thread-states. (line 29) * Waiting to get readlock, thread state: general-thread-states. (line 384) * Waiting to reconnect after a failed binlog dump request, thread state: slave-io-thread-states. (line 37) * Waiting to reconnect after a failed master event read, thread state: slave-io-thread-states. (line 62) * warning_count session variable: server-system-variables. (line 5975) * warnings command, mysql: mysql-commands. (line 235) * WEEK(): date-and-time-functions. (line 1181) * WEEKDAY(): date-and-time-functions. (line 1240) * WEEKOFYEAR(): date-and-time-functions. (line 1250) * Well-Known Binary format: gis-wkb-format. (line 6) * Well-Known Text format: gis-wkt-format. (line 6) * WHERE: where-optimizations. (line 6) * where option, mysqldump: mysqldump. (line 993) * WHERE, with SHOW <1>: extended-show. (line 6) * WHERE, with SHOW: information-schema. (line 37) * WHILE: while-statement. (line 6) * widths, display: data-types. (line 32) * Wildcard character (%): string-syntax. (line 65) * Wildcard character (_): string-syntax. (line 66) * wildcards, and LIKE: mysql-indexes. (line 111) * wildcards, in account names: account-names. (line 72) * wildcards, in mysql.columns_priv table: request-access. (line 59) * wildcards, in mysql.db table: request-access. (line 26) * wildcards, in mysql.host table: request-access. (line 26) * wildcards, in mysql.procs_priv table: request-access. (line 59) * wildcards, in mysql.tables_priv table: request-access. (line 59) * Windows <1>: connector-net. (line 18) * Windows: connector-odbc. (line 17) * windows option, mysql_install_db: mysql-install-db. (line 95) * Windows, compiling clients on: building-clients. (line 39) * Windows, MySQL limitations: limits-windows. (line 6) * Windows, path name separators: option-files. (line 183) * Windows, upgrading: windows-upgrading. (line 6) * with-big-tables option: source-configuration-options. (line 6) * with-big-tables option, configure: source-configuration-options. (line 528) * with-client-ldflags option, configure: source-configuration-options. (line 389) * with-debug option, configure: source-configuration-options. (line 476) * with-embedded-server option, configure: source-configuration-options. (line 346) * with-extra-charsets option, configure: source-configuration-options. (line 461) * with-tcp-port option, configure: source-configuration-options. (line 370) * with-unix-socket-path option, configure: source-configuration-options. (line 377) * with-zlib-dir option, configure: source-configuration-options. (line 519) * Within(): functions-that-test-spatial-relationships-between-geometries. (line 67) * without-server option: source-configuration-options. (line 6) * without-server option, configure: source-configuration-options. (line 332) * WKB format: gis-wkb-format. (line 6) * WKT format: gis-wkt-format. (line 6) * wrappers, Eiffel: apis-eiffel. (line 6) * write access, tmp: mysql-install-db-problems. (line 70) * write-binlog option, mysql_upgrade: mysql-upgrade. (line 161) * write-binlog option, mysqlcheck: mysqlcheck. (line 412) * write_buffer_size myisamchk variable: myisamchk-general-options. (line 53) * Writing to net, thread state: general-thread-states. (line 390) * X(): point-property-functions. (line 9) * X509/Certificate: secure-basics. (line 31) * XA BEGIN: xa-statements. (line 6) * XA COMMIT: xa-statements. (line 6) * XA PREPARE: xa-statements. (line 6) * XA RECOVER: xa-statements. (line 6) * XA ROLLBACK: xa-statements. (line 6) * XA START: xa-statements. (line 6) * XA transactions: xa. (line 11) * XA transactions, transaction identifiers: xa-statements. (line 6) * xid, XA transaction identifier: xa-statements. (line 6) * xml option, mysql: mysql-command-options. (line 561) * xml option, mysqldump: mysqldump. (line 1005) * xml option, ndb_config: mysql-cluster-programs-ndb-config. (line 298) * XOR, bitwise: bit-functions. (line 38) * XOR, logical: logical-operators. (line 84) * Y(): point-property-functions. (line 21) * yaSSL <1>: secure-using-ssl. (line 6) * yaSSL: secure-connections. (line 13) * Year 2000 compliance: y2k-issues. (line 6) * Year 2000 issues: y2k-issues. (line 6) * YEAR data type <1>: year. (line 6) * YEAR data type: date-and-time-type-overview. (line 70) * YEAR(): date-and-time-functions. (line 1259) * YEARWEEK(): date-and-time-functions. (line 1267) * Yen sign (Japanese): faqs-cjk. (line 6) * ZEROFILL <1>: c-api-prepared-statement-problems. (line 13) * ZEROFILL <2>: numeric-types. (line 6) * ZEROFILL: numeric-type-overview. (line 6) * | (bitwise OR): bit-functions. (line 20) * || (logical OR): logical-operators. (line 65) * ~: bit-functions. (line 75)  Tag Table: Node: Top167 Node: preface7460 Node: introduction8493 Node: manual-info11729 Node: manual-conventions13890 Node: what-is19020 Node: what-is-mysql19406 Node: history23613 Node: features24771 Node: development-history34263 Node: mysql-nutshell35536 Node: information-sources44850 Node: mailing-lists45454 Node: mailing-list-use50488 Node: forums51593 Node: irc52140 Node: mysql-enterprise-information53100 Node: bug-reports53890 Node: compatibility71269 Node: standards74038 Node: sql-mode74351 Node: ansi-mode75340 Node: extensions-to-ansi76537 Node: differences-from-ansi86445 Node: ansi-diff-select-into-table87585 Node: ansi-diff-update88496 Node: ansi-diff-transactions89085 Node: ansi-diff-foreign-keys97991 Node: ansi-diff-comments102771 Node: constraints105440 Node: constraint-primary-key107406 Node: constraint-invalid-data108776 Node: constraint-enum114597 Node: credits117213 Node: contributors117745 Node: documenters-translators126555 Node: packages128972 Node: tools-used-to-create-mysql130173 Node: supporters131203 Node: installing132141 Node: general-installation-issues137808 Node: supported-os138891 Node: which-version142656 Node: choosing-version143406 Node: choosing-distribution-format149863 Node: many-versions152904 Node: getting-mysql154764 Node: verifying-package-integrity155409 Node: verifying-md5-checksum156790 Node: checking-gpg-signature158488 Node: checking-rpm-signature164307 Node: installation-layouts165699 Node: compiler-characteristics166581 Node: binary-installation167175 Ref: binary-installation-layout169866 Ref: binary-installation-createsysuser172075 Ref: binary-installation-unpack172977 Ref: binary-installation-postinstall174396 Node: windows-installation174837 Node: windows-installation-layout180959 Node: windows-choosing-package183407 Ref: installer-windows-workflow-msi185076 Ref: installer-windows-workflow-zip185208 Node: windows-using-installer187713 Ref: installer-windows-workflow-installer189216 Node: windows-install-wizard191388 Node: mysql-install-wizard-starting193883 Node: mysql-install-wizard-install-type194639 Node: mysql-install-wizard-custom-install196167 Node: mysql-install-wizard-confirmation-dialog197228 Node: mysql-install-wizard-changes198552 Node: mysql-install-wizard-upgrading202513 Node: windows-installer-msi-quiet204841 Node: windows-installer-uninstalling206995 Node: mysql-config-wizard209183 Ref: installer-windows-instance-workflow211393 Node: mysql-config-wizard-starting211457 Node: mysql-config-wizard-maintenance214608 Node: mysql-config-wizard-configuration-type216009 Node: mysql-config-wizard-server-type217835 Node: mysql-config-wizard-database-usage219572 Node: mysql-config-wizard-tablespace221825 Node: mysql-config-wizard-connections222989 Node: mysql-config-wizard-networking224505 Node: mysql-config-wizard-character-set225858 Node: mysql-config-wizard-service227130 Node: mysql-config-wizard-security229267 Node: mysql-config-wizard-confirmation231934 Node: mysql-config-wizard-cmdline233745 Node: windows-install-archive241188 Node: windows-extract-archive242541 Node: windows-create-option-file243726 Node: windows-select-server247159 Node: windows-server-first-start249920 Node: windows-start-command-line253575 Node: mysql-installation-windows-path255849 Node: windows-start-service257957 Node: windows-testing264765 Node: windows-troubleshooting266584 Node: windows-upgrading271974 Node: windows-postinstallation275375 Node: macosx-installation279938 Node: macosx-installation-notes282546 Node: macosx-installation-pkg286322 Ref: mysql-installation-layout-macosx287904 Node: macosx-installation-startupitem290742 Node: macosx-installation-prefpane293241 Node: macosx-installation-server296359 Node: linux-installation298884 Node: linux-installation-rpm300959 Ref: mysql-installation-layout-linuxrpm301704 Node: linux-installation-native312362 Node: solaris-installation324694 Node: solaris-installation-pkg328322 Node: solaris-installation-opensolaris331159 Node: aix-installation334290 Node: aix-installation-general335272 Node: hpux-installation335628 Node: hpux-installation-general336973 Node: hpux-installation-depot338013 Node: freebsd-installation339968 Node: i5os-installation341907 Ref: installation-i5os-notes352942 Node: source-installation353691 Node: source-installation-layout357828 Node: installing-source-distribution359621 Node: installing-development-tree365675 Node: source-configuration-options374340 Ref: option_configure_without-server396229 Ref: option_configure_with-embedded-server396945 Ref: option_configure_prefix397051 Ref: option_configure_with-tcp-port398068 Ref: option_configure_with-unix-socket-path398342 Ref: option_configure_with-client-ldflags398863 Ref: option_configure_with-charset400861 Ref: option_configure_with-collation401573 Ref: option_configure_with-extra-charsets402133 Ref: option_configure_with-debug402705 Ref: option_configure_enable-debug-sync403443 Ref: 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rebuilding-tables559955 Node: copying-databases563661 Node: environment-variables566659 Node: perl-support571348 Node: perl-installation572900 Node: activestate-perl575776 Node: perl-support-problems576943 Node: tutorial579629 Node: connecting-disconnecting581654 Node: entering-queries584393 Node: database-use593200 Node: creating-database596439 Node: creating-tables598859 Node: loading-tables603299 Node: retrieving-data606910 Node: selecting-all608118 Node: selecting-rows610337 Node: selecting-columns614139 Node: sorting-rows616287 Node: date-calculations619185 Node: working-with-null626808 Node: pattern-matching629353 Node: counting-rows636860 Node: multiple-tables641900 Node: getting-information647226 Node: batch-mode650280 Node: examples653499 Node: example-maximum-column655705 Node: example-maximum-row656062 Node: example-maximum-column-group657204 Node: example-maximum-column-group-row657743 Node: example-user-variables659424 Node: example-foreign-keys660517 Node: searching-on-two-keys664776 Node: calculating-days665724 Node: example-auto-increment666901 Node: apache671707 Node: programs672605 Node: programs-overview673694 Node: programs-using685881 Node: invoking-programs686297 Node: connecting689758 Ref: option_general_host695422 Ref: option_general_password695547 Ref: option_general_pipe695840 Ref: option_general_port696031 Ref: option_general_protocol696193 Ref: option_general_shared-memory-base-name697545 Ref: option_general_socket697885 Ref: option_general_user698615 Node: program-options699766 Node: command-line-options702816 Node: option-modifiers708189 Node: option-files710242 Node: option-file-options722372 Ref: option_general_defaults-extra-file723313 Ref: option_general_defaults-file723604 Ref: option_general_defaults-group-suffix723822 Ref: option_general_no-defaults724262 Ref: option_general_print-defaults724488 Node: option-files-preconfigured724591 Node: program-variables725578 Node: option-defaults-equals728867 Node: setting-environment-variables736078 Node: programs-server739064 Node: mysqld739704 Node: mysqld-safe741148 Ref: option_mysqld_safe_help748180 Ref: option_mysqld_safe_autoclose748235 Ref: option_mysqld_safe_basedir748722 Ref: option_mysqld_safe_core-file-size748798 Ref: option_mysqld_safe_datadir748965 Ref: option_mysqld_safe_defaults-extra-file749027 Ref: option_mysqld_safe_defaults-file749319 Ref: option_mysqld_safe_ledir749508 Ref: option_mysqld_safe_log-error749695 Ref: option_mysqld_safe_mysqld749794 Ref: option_mysqld_safe_mysqld-version750222 Ref: option_mysqld_safe_nice750756 Ref: option_mysqld_safe_no-defaults750875 Ref: option_mysqld_safe_open-files-limit751004 Ref: option_mysqld_safe_pid-file751274 Ref: option_mysqld_safe_port751348 Ref: option_mysqld_safe_skip-kill-mysqld751566 Ref: option_mysqld_safe_socket751709 Ref: option_mysqld_safe_syslog751829 Ref: option_mysqld_safe_syslog-tag752121 Ref: option_mysqld_safe_timezone752511 Ref: option_mysqld_safe_user752714 Node: 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Ref: option_mysql_install_db_skip-name-resolve786804 Ref: option_mysql_install_db_srcdir786972 Ref: option_mysql_install_db_user787243 Ref: option_mysql_install_db_verbose787622 Ref: option_mysql_install_db_windows787713 Node: mysql-secure-installation787812 Node: mysql-tzinfo-to-sql789052 Node: mysql-upgrade791219 Ref: option_mysql_upgrade_help796642 Ref: option_mysql_upgrade_basedir796703 Ref: option_mysql_upgrade_datadir796848 Ref: option_mysql_upgrade_debug-check796979 Ref: option_mysql_upgrade_debug-info797110 Ref: option_mysql_upgrade_force797276 Ref: option_mysql_upgrade_tmpdir797512 Ref: option_mysql_upgrade_user797664 Ref: option_mysql_upgrade_verbose797809 Ref: option_mysql_upgrade_write-binlog797900 Node: programs-client798239 Node: mysql799052 Node: mysql-command-options801278 Ref: option_mysql_help811957 Ref: option_mysql_auto-rehash812018 Ref: option_mysql_batch812673 Ref: option_mysql_bind-address813048 Ref: option_mysql_character-sets-dir813479 Ref: 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option_mysql_port821195 Ref: option_mysql_prompt821291 Ref: option_mysql_protocol821492 Ref: option_mysql_quick821805 Ref: option_mysql_raw822039 Ref: option_mysql_reconnect822995 Ref: option_mysql_safe-updates823238 Ref: option_mysql_secure-auth823626 Ref: option_mysql_show-warnings823809 Ref: option_mysql_sigint-ignore823962 Ref: option_mysql_silent824061 Ref: option_mysql_skip-column-names824391 Ref: option_mysql_skip-line-numbers824470 Ref: option_mysql_socket824628 Ref: option_mysql_ssl824785 Ref: option_mysql_table824979 Ref: option_mysql_tee825146 Ref: option_mysql_unbuffered825327 Ref: option_mysql_user825396 Ref: option_mysql_verbose825502 Ref: option_mysql_version825759 Ref: option_mysql_vertical825828 Ref: option_mysql_wait826044 Ref: option_mysql_xml826154 Ref: option_mysql_connect_timeout827791 Ref: option_mysql_max_allowed_packet827900 Ref: option_mysql_max_join_size828029 Ref: option_mysql_select_limit828277 Node: mysql-commands828419 Node: mysql-history-file843503 Node: mysql-server-side-help844765 Node: batch-commands847144 Node: mysql-tips848959 Node: vertical-query-results849391 Node: safe-updates850631 Node: mysql-reconnect852433 Node: mysqladmin854099 Ref: command_mysqladmin_db_name854790 Ref: command_mysqladmin_debug854857 Ref: command_mysqladmin_drop855064 Ref: command_mysqladmin_extended-status855146 Ref: command_mysqladmin_flush-hosts855231 Ref: command_mysqladmin_flush-logs855299 Ref: command_mysqladmin_flush-privileges855341 Ref: command_mysqladmin_flush-status855417 Ref: command_mysqladmin_flush-tables855469 Ref: command_mysqladmin_flush-threads855515 Ref: command_mysqladmin_kill855568 Ref: command_mysqladmin_old-password855701 Ref: command_mysqladmin_password855893 Ref: command_mysqladmin_ping857299 Ref: command_mysqladmin_processlist857662 Ref: command_mysqladmin_reload857977 Ref: command_mysqladmin_refresh858024 Ref: command_mysqladmin_shutdown858094 Ref: command_mysqladmin_start-slave858135 Ref: command_mysqladmin_status858199 Ref: command_mysqladmin_stop-slave858260 Ref: command_mysqladmin_variables858322 Ref: command_mysqladmin_version858401 Ref: option_mysqladmin_help866477 Ref: option_mysqladmin_bind-address866538 Ref: option_mysqladmin_character-sets-dir866968 Ref: option_mysqladmin_compress867099 Ref: option_mysqladmin_count867229 Ref: option_mysqladmin_debug867365 Ref: option_mysqladmin_debug-check867563 Ref: option_mysqladmin_debug-info867694 Ref: option_mysqladmin_default-character-set867854 Ref: option_mysqladmin_force867993 Ref: option_mysqladmin_host868145 Ref: option_mysqladmin_no-beep868240 Ref: option_mysqladmin_password868428 Ref: option_mysqladmin_pipe869001 Ref: option_mysqladmin_port869160 Ref: option_mysqladmin_protocol869256 Ref: option_mysqladmin_relative869569 Ref: option_mysqladmin_silent869767 Ref: option_mysqladmin_sleep869864 Ref: option_mysqladmin_socket870155 Ref: option_mysqladmin_ssl870312 Ref: option_mysqladmin_user870506 Ref: option_mysqladmin_verbose870612 Ref: option_mysqladmin_version870709 Ref: option_mysqladmin_vertical870778 Ref: option_mysqladmin_wait870903 Ref: option_mysqladmin_connect_timeout871270 Ref: option_mysqladmin_shutdown_timeout871402 Node: mysqlcheck871530 Ref: option_mysqlcheck_help883309 Ref: option_mysqlcheck_all-databases883370 Ref: option_mysqlcheck_all-in-1883553 Ref: option_mysqlcheck_analyze883749 Ref: option_mysqlcheck_auto-repair883800 Ref: option_mysqlcheck_bind-address883956 Ref: option_mysqlcheck_character-sets-dir884386 Ref: option_mysqlcheck_check884517 Ref: option_mysqlcheck_check-only-changed884606 Ref: option_mysqlcheck_check-upgrade884749 Ref: option_mysqlcheck_compress885088 Ref: option_mysqlcheck_databases885212 Ref: option_mysqlcheck_debug885522 Ref: option_mysqlcheck_debug-check885693 Ref: option_mysqlcheck_debug-info885824 Ref: option_mysqlcheck_default-character-set885984 Ref: option_mysqlcheck_extended886123 Ref: option_mysqlcheck_fast886451 Ref: option_mysqlcheck_fix-db-names886533 Ref: option_mysqlcheck_fix-table-names886715 Ref: option_mysqlcheck_force886949 Ref: option_mysqlcheck_host887016 Ref: option_mysqlcheck_medium-check887111 Ref: option_mysqlcheck_optimize887297 Ref: option_mysqlcheck_password887350 Ref: option_mysqlcheck_pipe887923 Ref: option_mysqlcheck_port888082 Ref: option_mysqlcheck_protocol888178 Ref: option_mysqlcheck_quick888491 Ref: option_mysqlcheck_repair888818 Ref: option_mysqlcheck_silent888939 Ref: option_mysqlcheck_socket889009 Ref: option_mysqlcheck_ssl889166 Ref: option_mysqlcheck_tables889360 Ref: option_mysqlcheck_use-frm889501 Ref: option_mysqlcheck_user889697 Ref: option_mysqlcheck_verbose889803 Ref: option_mysqlcheck_version889918 Ref: option_mysqlcheck_write-binlog889987 Node: mysqldump890607 Ref: option_mysqldump_help911917 Ref: option_mysqldump_add-drop-database911978 Ref: option_mysqldump_add-drop-table912372 Ref: option_mysqldump_add-drop-trigger912517 Ref: option_mysqldump_add-locks912940 Ref: option_mysqldump_all-databases913187 Ref: option_mysqldump_all-tablespaces913369 Ref: option_mysqldump_allow-keywords913754 Ref: option_mysqldump_bind-address913904 Ref: option_mysqldump_character-sets-dir914332 Ref: option_mysqldump_comments914463 Ref: option_mysqldump_compact914706 Ref: option_mysqldump_compatible915310 Ref: option_mysqldump_complete-insert916226 Ref: option_mysqldump_compress916346 Ref: option_mysqldump_create-options916476 Ref: option_mysqldump_databases916609 Ref: option_mysqldump_debug917032 Ref: option_mysqldump_debug-check917235 Ref: option_mysqldump_debug-info917366 Ref: option_mysqldump_default-character-set917526 Ref: option_mysqldump_delayed-insert917950 Ref: option_mysqldump_delete-master-logs918094 Ref: option_mysqldump_disable-keys918373 Ref: option_mysqldump_dump-date918789 Ref: option_mysqldump_events919387 Ref: option_mysqldump_extended-insert919531 Ref: option_mysqldump_fields919752 Ref: option_mysqldump_first-slave920091 Ref: option_mysqldump_flush-logs920212 Ref: option_mysqldump_flush-privileges920852 Ref: option_mysqldump_force921216 Ref: option_mysqldump_host921811 Ref: option_mysqldump_hex-blob921948 Ref: option_mysqldump_ignore-table922241 Ref: option_mysqldump_insert-ignore922502 Ref: option_mysqldump_lines-terminated-by922634 Ref: option_mysqldump_lock-all-tables922854 Ref: option_mysqldump_lock-tables923111 Ref: option_mysqldump_log-error923783 Ref: option_mysqldump_master-data923959 Ref: option_mysqldump_no-autocommit926817 Ref: option_mysqldump_no-create-db926995 Ref: option_mysqldump_no-create-info927222 Ref: option_mysqldump_no-data927611 Ref: option_mysqldump_no-set-names927922 Ref: option_mysqldump_no-tablespaces928008 Ref: option_mysqldump_opt928293 Ref: option_mysqldump_order-by-primary928891 Ref: option_mysqldump_password929186 Ref: option_mysqldump_pipe929757 Ref: option_mysqldump_port929916 Ref: option_mysqldump_protocol930012 Ref: option_mysqldump_quick930325 Ref: option_mysqldump_quote-names930610 Ref: option_mysqldump_replace931033 Ref: option_mysqldump_result-file931198 Ref: option_mysqldump_routines931564 Ref: option_mysqldump_set-charset932960 Ref: option_mysqldump_single-transaction933152 Ref: option_mysqldump_skip-comments935082 Ref: option_mysqldump_skip-opt935162 Ref: option_mysqldump_socket935232 Ref: option_mysqldump_ssl935389 Ref: option_mysqldump_tab935583 Ref: option_mysqldump_tables936984 Ref: option_mysqldump_triggers937156 Ref: option_mysqldump_tz-utc937311 Ref: option_mysqldump_user938036 Ref: option_mysqldump_verbose938142 Ref: option_mysqldump_version938239 Ref: option_mysqldump_where938308 Ref: option_mysqldump_xml938664 Ref: option_mysqldump_net_buffer_length941851 Node: mysqlimport944993 Ref: option_mysqlimport_help953326 Ref: option_mysqlimport_bind-address953387 Ref: option_mysqlimport_character-sets-dir953819 Ref: option_mysqlimport_columns953950 Ref: option_mysqlimport_compress954177 Ref: option_mysqlimport_debug954307 Ref: option_mysqlimport_debug-check954478 Ref: option_mysqlimport_debug-info954609 Ref: option_mysqlimport_default-character-set954769 Ref: option_mysqlimport_delete954908 Ref: option_mysqlimport_fields954986 Ref: option_mysqlimport_force955274 Ref: option_mysqlimport_host955511 Ref: option_mysqlimport_ignore955648 Ref: option_mysqlimport_ignore-lines955726 Ref: option_mysqlimport_lines-terminated-by955801 Ref: option_mysqlimport_local956241 Ref: option_mysqlimport_lock-tables956317 Ref: option_mysqlimport_low-priority956482 Ref: option_mysqlimport_password956677 Ref: option_mysqlimport_pipe957252 Ref: option_mysqlimport_port957411 Ref: option_mysqlimport_protocol957507 Ref: option_mysqlimport_replace957820 Ref: option_mysqlimport_silent958335 Ref: option_mysqlimport_socket958417 Ref: option_mysqlimport_ssl958574 Ref: option_mysqlimport_user958768 Ref: option_mysqlimport_use-threads958874 Ref: option_mysqlimport_verbose958988 Ref: option_mysqlimport_version959085 Node: mysqlshow959964 Ref: option_mysqlshow_help966479 Ref: option_mysqlshow_bind-address966540 Ref: option_mysqlshow_character-sets-dir966968 Ref: option_mysqlshow_compress967099 Ref: option_mysqlshow_count967229 Ref: option_mysqlshow_debug967334 Ref: option_mysqlshow_debug-check967505 Ref: option_mysqlshow_debug-info967636 Ref: option_mysqlshow_default-character-set967796 Ref: option_mysqlshow_host967935 Ref: option_mysqlshow_keys968030 Ref: option_mysqlshow_password968078 Ref: option_mysqlshow_pipe968649 Ref: option_mysqlshow_port968808 Ref: option_mysqlshow_protocol968904 Ref: option_mysqlshow_show-table-type969217 Ref: option_mysqlshow_socket969364 Ref: option_mysqlshow_ssl969521 Ref: option_mysqlshow_status969715 Ref: option_mysqlshow_user969789 Ref: option_mysqlshow_verbose969895 Ref: option_mysqlshow_version970080 Node: mysqlslap970144 Ref: option_mysqlslap_help983489 Ref: option_mysqlslap_auto-generate-sql983550 Ref: option_mysqlslap_auto-generate-sql-add-autoincrement983696 Ref: option_mysqlslap_auto-generate-sql-execute-number983859 Ref: option_mysqlslap_auto-generate-sql-guid-primary984007 Ref: option_mysqlslap_auto-generate-sql-load-type984163 Ref: option_mysqlslap_auto-generate-sql-secondary-indexes984512 Ref: option_mysqlslap_auto-generate-sql-unique-query-number984721 Ref: option_mysqlslap_auto-generate-sql-unique-write-number985110 Ref: option_mysqlslap_auto-generate-sql-write-number985315 Ref: option_mysqlslap_commit985477 Ref: option_mysqlslap_compress985637 Ref: option_mysqlslap_concurrency985767 Ref: option_mysqlslap_create985897 Ref: option_mysqlslap_create-and-drop-schema986007 Ref: option_mysqlslap_create-schema986216 Ref: option_mysqlslap_csv986561 Ref: option_mysqlslap_debug986774 Ref: option_mysqlslap_debug-check986971 Ref: option_mysqlslap_debug-info987102 Ref: option_mysqlslap_delimiter987268 Ref: option_mysqlslap_detach987397 Ref: option_mysqlslap_engine987588 Ref: option_mysqlslap_host987689 Ref: option_mysqlslap_iterations987784 Ref: option_mysqlslap_lock-directory987860 Ref: option_mysqlslap_number-char-cols988002 Ref: option_mysqlslap_number-int-cols988142 Ref: option_mysqlslap_number-of-queries988286 Ref: option_mysqlslap_only-print988841 Ref: option_mysqlslap_password989014 Ref: option_mysqlslap_pipe989585 Ref: option_mysqlslap_port989744 Ref: option_mysqlslap_post-query989840 Ref: option_mysqlslap_shared-memory-base-name990061 Ref: option_mysqlslap_post-system990295 Ref: option_mysqlslap_pre-query990499 Ref: option_mysqlslap_pre-system990713 Ref: option_mysqlslap_preserve-schema990910 Ref: option_mysqlslap_protocol991159 Ref: option_mysqlslap_query991472 Ref: option_mysqlslap_silent991614 Ref: option_mysqlslap_slave991668 Ref: option_mysqlslap_socket991944 Ref: option_mysqlslap_ssl992101 Ref: option_mysqlslap_use-threads992295 Ref: option_mysqlslap_user992586 Ref: option_mysqlslap_verbose992692 Ref: option_mysqlslap_version992877 Node: programs-admin-utils992941 Node: innochecksum994710 Ref: option_innochecksum_count996246 Ref: option_innochecksum_debug996314 Ref: option_innochecksum_end996376 Ref: option_innochecksum_page996423 Ref: option_innochecksum_start996474 Ref: option_innochecksum_verbose996523 Node: myisam-ftdump996597 Ref: option_myisam_ftdump_help998967 Ref: option_myisam_ftdump_count999033 Ref: option_myisam_ftdump_dump999121 Ref: option_myisam_ftdump_length999206 Ref: option_myisam_ftdump_stats999268 Ref: option_myisam_ftdump_verbose999400 Node: myisamchk999487 Node: myisamchk-general-options1013425 Ref: option_myisamchk_help1013890 Ref: option_myisamchk_HELP1013998 Ref: option_myisamchk_debug1014104 Ref: option_myisamchk_silent1014297 Ref: option_myisamchk_verbose1014464 Ref: option_myisamchk_version1014670 Ref: option_myisamchk_wait1014739 Node: myisamchk-check-options1019036 Ref: option_myisamchk_check1019339 Ref: option_myisamchk_check-only-changed1019499 Ref: option_myisamchk_extend-check1019599 Ref: option_myisamchk_fast1020204 Ref: option_myisamchk_force1020285 Ref: option_myisamchk_information1020508 Ref: option_myisamchk_medium-check1020607 Ref: option_myisamchk_read-only1020796 Ref: option_myisamchk_update-state1021092 Node: myisamchk-repair-options1021479 Ref: option_myisamchk_backup1021867 Ref: option_myisamchk_character-sets-dir1021954 Ref: option_myisamchk_correct-checksum1022085 Ref: option_myisamchk_data-file-length1022167 Ref: option_myisamchk_extended-check1022304 Ref: option_myisamchk_keys-used1022732 Ref: option_myisamchk_no-symlinks1023178 Ref: option_myisamchk_max-record-length1023462 Ref: option_myisamchk_parallel-recover1023615 Ref: option_myisamchk_quick1023819 Ref: option_myisamchk_recover1024073 Ref: option_myisamchk_safe-recover1024644 Ref: option_myisamchk_set-character-set1025240 Ref: option_myisamchk_set-collation1025399 Ref: option_myisamchk_sort-recover1025576 Ref: option_myisamchk_tmpdir1025737 Ref: option_myisamchk_unpack1026241 Node: myisamchk-other-options1026334 Ref: option_myisamchk_analyze1026650 Ref: option_myisamchk_block-search1027069 Ref: option_myisamchk_description1027180 Ref: option_myisamchk_set-auto-increment1027393 Ref: option_myisamchk_sort-index1027762 Ref: option_myisamchk_sort-records1027915 Node: myisamchk-table-info1028905 Node: myisamchk-memory1043208 Node: myisamlog1046257 Ref: option_myisamlog_help1047143 Ref: option_myisamlog_files1047244 Ref: option_myisamlog_information1047306 Ref: option_myisamlog_offset1047366 Ref: option_myisamlog_path1047420 Ref: option_myisamlog_recovery1047471 Ref: option_myisamlog_record-position1047519 Ref: option_myisamlog_update1047614 Ref: option_myisamlog_verbose1047661 Ref: option_myisamlog_write1047819 Ref: option_myisamlog_version1047872 Node: myisampack1047914 Ref: option_myisampack_help1049895 Ref: option_myisampack_backup1049956 Ref: option_myisampack_character-sets-dir1050062 Ref: option_myisampack_debug1050193 Ref: option_myisampack_force1050364 Ref: option_myisampack_join1050997 Ref: option_myisampack_silent1051711 Ref: option_myisampack_test1051791 Ref: option_myisampack_tmpdir1051873 Ref: option_myisampack_verbose1052021 Ref: option_myisampack_version1052149 Ref: option_myisampack_wait1052218 Node: mysqlaccess1063348 Ref: option_mysqlaccess_help1067405 Ref: option_mysqlaccess_brief1067466 Ref: option_mysqlaccess_commit1067543 Ref: option_mysqlaccess_copy1067814 Ref: option_mysqlaccess_db1067890 Ref: option_mysqlaccess_debug1067959 Ref: option_mysqlaccess_host1068042 Ref: option_mysqlaccess_howto1068137 Ref: option_mysqlaccess_old_server1068242 Ref: option_mysqlaccess_password1068400 Ref: option_mysqlaccess_plan1068779 Ref: option_mysqlaccess_preview1068852 Ref: option_mysqlaccess_relnotes1068965 Ref: option_mysqlaccess_rhost1069018 Ref: option_mysqlaccess_rollback1069114 Ref: option_mysqlaccess_spassword1069200 Ref: option_mysqlaccess_superuser1069603 Ref: option_mysqlaccess_table1069711 Ref: option_mysqlaccess_user1069774 Ref: option_mysqlaccess_version1069869 Node: mysqlbinlog1070499 Ref: option_mysqlbinlog_help1081017 Ref: option_mysqlbinlog_base64-output1081078 Ref: option_mysqlbinlog_bind-address1083429 Ref: option_mysqlbinlog_character-sets-dir1083861 Ref: option_mysqlbinlog_database1083992 Ref: option_mysqlbinlog_debug1087773 Ref: option_mysqlbinlog_debug-check1087972 Ref: option_mysqlbinlog_debug-info1088103 Ref: option_mysqlbinlog_disable-log-bin1088263 Ref: option_mysqlbinlog_force-read1088925 Ref: option_mysqlbinlog_hexdump1089225 Ref: option_mysqlbinlog_host1089449 Ref: option_mysqlbinlog_local-load1089557 Ref: option_mysqlbinlog_offset1089852 Ref: option_mysqlbinlog_password1089923 Ref: option_mysqlbinlog_port1090498 Ref: option_mysqlbinlog_position1090609 Ref: option_mysqlbinlog_protocol1090724 Ref: option_mysqlbinlog_read-from-remote-server1091037 Ref: option_mysqlbinlog_result-file1091501 Ref: option_mysqlbinlog_server-id1091579 Ref: option_mysqlbinlog_server-id-bits1091734 Ref: option_mysqlbinlog_set-charset1092349 Ref: option_mysqlbinlog_short-form1092561 Ref: option_mysqlbinlog_socket1092778 Ref: option_mysqlbinlog_start-datetime1092935 Ref: option_mysqlbinlog_start-position1093546 Ref: option_mysqlbinlog_stop-datetime1093859 Ref: option_mysqlbinlog_stop-position1094269 Ref: option_mysqlbinlog_to-last-log1094571 Ref: option_mysqlbinlog_user1094898 Ref: option_mysqlbinlog_verbose1095009 Ref: option_mysqlbinlog_version1095416 Ref: option_mysqlbinlog_open_files_limit1095562 Node: mysqlbinlog-hexdump1099540 Node: mysqlbinlog-row-events1110326 Node: mysqldumpslow1119314 Ref: option_mysqldumpslow_help1121651 Ref: option_mysqldumpslow_abstract1121706 Ref: option_mysqldumpslow_debug1121781 Ref: option_mysqldumpslow_grep1121829 Ref: option_mysqldumpslow_host1121916 Ref: option_mysqldumpslow_instance1122069 Ref: option_mysqldumpslow_lock1122184 Ref: option_mysqldumpslow_abstract-numbers1122245 Ref: option_mysqldumpslow_reverse1122319 Ref: option_mysqldumpslow_sort1122361 Ref: option_mysqldumpslow_top1122812 Ref: option_mysqldumpslow_verbose1122880 Node: mysqlhotcopy1123480 Ref: option_mysqlhotcopy_help1127843 Ref: option_mysqlhotcopy_addtodest1127904 Ref: option_mysqlhotcopy_allowold1128007 Ref: option_mysqlhotcopy_checkpoint1128109 Ref: option_mysqlhotcopy_chroot1128241 Ref: option_mysqlhotcopy_debug1128450 Ref: option_mysqlhotcopy_dryrun1128494 Ref: option_mysqlhotcopy_flushlog1128564 Ref: option_mysqlhotcopy_host1128630 Ref: option_mysqlhotcopy_keepold1128855 Ref: option_mysqlhotcopy_method1128931 Ref: option_mysqlhotcopy_noindices1129030 Ref: option_mysqlhotcopy_password1129310 Ref: option_mysqlhotcopy_port1129707 Ref: option_mysqlhotcopy_quiet1129820 Ref: option_mysqlhotcopy_record_log_pos1129878 Ref: option_mysqlhotcopy_regexp1130017 Ref: option_mysqlhotcopy_resetmaster1130122 Ref: option_mysqlhotcopy_resetslave1130202 Ref: option_mysqlhotcopy_socket1130289 Ref: option_mysqlhotcopy_suffix1130389 Ref: option_mysqlhotcopy_tmpdir1130466 Ref: option_mysqlhotcopy_user1130543 Node: instance-manager1130877 Node: instance-manager-command-options1133754 Ref: option_mysqlmanager_help1134751 Ref: option_mysqlmanager_add-user1134812 Ref: option_mysqlmanager_angel-pid-file1134960 Ref: option_mysqlmanager_bind-address1135547 Ref: option_mysqlmanager_check-password-file1135607 Ref: option_mysqlmanager_clean-password-file1135746 Ref: option_mysqlmanager_debug1135866 Ref: option_mysqlmanager_default-mysqld-path1136046 Ref: option_mysqlmanager_defaults-file1136456 Ref: option_mysqlmanager_drop-user1137002 Ref: option_mysqlmanager_edit-user1137150 Ref: option_mysqlmanager_install1137326 Ref: option_mysqlmanager_list-users1137453 Ref: option_mysqlmanager_log1137562 Ref: option_mysqlmanager_monitoring-interval1138294 Ref: option_mysqlmanager_mysqld-safe-compatible1139582 Ref: option_mysqlmanager_password1139793 Ref: option_mysqlmanager_password-file1140146 Ref: option_mysqlmanager_pid-file1140500 Ref: option_mysqlmanager_port1140750 Ref: option_mysqlmanager_print-defaults1140913 Ref: option_mysqlmanager_print-password-line1141052 Ref: option_mysqlmanager_remove1141336 Ref: option_mysqlmanager_run-as-service1141507 Ref: option_mysqlmanager_socket1141731 Ref: option_mysqlmanager_standalone1141920 Ref: option_mysqlmanager_user1142110 Ref: option_mysqlmanager_username1142666 Ref: option_mysqlmanager_version1142846 Ref: option_mysqlmanager_wait-timeout1142915 Node: instance-manager-configuration-files1143191 Node: instance-manager-startup-process1146744 Node: instance-manager-security-passwords1151686 Node: instance-manager-security-monitoring1158741 Node: instance-manager-security1162411 Node: instance-manager-commands1163339 Node: mysql-convert-table-format1174460 Ref: option_mysql_convert_table_format_help1175449 Ref: option_mysql_convert_table_format_force1175504 Ref: option_mysql_convert_table_format_host1175558 Ref: option_mysql_convert_table_format_password1175637 Ref: option_mysql_convert_table_format_port1176030 Ref: option_mysql_convert_table_format_socket1176111 Ref: option_mysql_convert_table_format_type1176201 Ref: option_mysql_convert_table_format_user1176364 Ref: option_mysql_convert_table_format_verbose1176454 Ref: option_mysql_convert_table_format_version1176545 Node: mysql-find-rows1176603 Ref: option_mysql_find_rows_help1177878 Ref: option_mysql_find_rows_regexp1177950 Ref: option_mysql_find_rows_rows1178022 Ref: option_mysql_find_rows_skip-use-db1178079 Ref: option_mysql_find_rows_start_row1178163 Node: mysql-fix-extensions1178215 Node: mysql-setpermission1179167 Ref: option_mysql_setpermission_help1180424 Ref: option_mysql_setpermission_host1180479 Ref: option_mysql_setpermission_password1180558 Ref: option_mysql_setpermission_port1180951 Ref: option_mysql_setpermission_socket1181032 Ref: option_mysql_setpermission_user1181122 Node: mysql-waitpid1181207 Ref: option_mysql_waitpid_help1182289 Ref: option_mysql_waitpid_verbose1182356 Ref: option_mysql_waitpid_version1182484 Node: mysql-zap1182548 Ref: option_mysql_zap_help1183648 Ref: option_mysql_zap_force1183715 Ref: option_mysql_zap_test1183832 Node: programs-development1183920 Node: msql2mysql1185851 Node: mysql-config1186997 Ref: option_mysql_config_cflags1187452 Ref: option_mysql_config_include1187858 Ref: option_mysql_config_libmysqld-libs1187929 Ref: option_mysql_config_libs1188051 Ref: option_mysql_config_libs_r1188148 Ref: option_mysql_config_plugindir1188259 Ref: option_mysql_config_port1188402 Ref: option_mysql_config_socket1188488 Ref: option_mysql_config_version1188574 Node: my-print-defaults1190099 Ref: option_my_print_defaults_help1191129 Ref: option_my_print_defaults_config-file1191190 Ref: option_my_print_defaults_debug1191313 Ref: option_my_print_defaults_defaults-extra-file1191514 Ref: option_my_print_defaults_defaults-group-suffix1191708 Ref: option_my_print_defaults_no-defaults1191865 Ref: option_my_print_defaults_verbose1191924 Ref: option_my_print_defaults_version1192021 Node: resolve-stack-dump1192085 Ref: option_resolve_stack_dump_help1192934 Ref: option_resolve_stack_dump_numeric-dump-file1192995 Ref: option_resolve_stack_dump_symbols-file1193098 Ref: option_resolve_stack_dump_version1193182 Node: programs-miscellaneous1193246 Node: perror1193644 Ref: option_perror_help1194902 Ref: option_perror_ndb1194979 Ref: option_perror_silent1195056 Ref: option_perror_verbose1195129 Ref: option_perror_version1195239 Node: replace-utility1195303 Ref: option_replace_help1196839 Ref: option_replace_debug1196896 Ref: option_replace_silent1196945 Ref: option_replace_verbose1197022 Ref: option_replace_version1197106 Node: resolveip1197157 Ref: option_resolveip_help1197653 Ref: option_resolveip_silent1197730 Ref: option_resolveip_version1197794 Node: server-administration1197858 Node: mysqld-server1198796 Node: mysqld-option-tables1200040 Node: server-options1276400 Ref: option_mysqld_help1279725 Ref: option_mysqld_allow-suspicious-udfs1280064 Ref: option_mysqld_ansi1280907 Ref: option_mysqld_basedir1281331 Ref: option_mysqld_big-tables1282124 Ref: option_mysqld_bind-address1283095 Ref: option_mysqld_binlog-format1283964 Ref: option_mysqld_bootstrap1287106 Ref: option_mysqld_character-sets-dir1287622 Ref: option_mysqld_character-set-client-handshake1288414 Ref: option_mysqld_character-set-filesystem1289140 Ref: option_mysqld_character-set-server1290057 Ref: option_mysqld_chroot1291019 Ref: option_mysqld_collation-server1291826 Ref: option_mysqld_console1292606 Ref: option_mysqld_core-file1293029 Ref: option_mysqld_datadir1294451 Ref: option_mysqld_debug1295166 Ref: option_mysqld_debug-sync-timeout1296723 Ref: option_mysqld_default-character-set1298047 Ref: option_mysqld_default-collation1298827 Ref: option_mysqld_default-storage-engine1299497 Ref: option_mysqld_default-table-type1300030 Ref: option_mysqld_default-time-zone1300693 Ref: option_mysqld_delay-key-write1301362 Ref: option_mysqld_des-key-file1302848 Ref: option_mysqld_enable-named-pipe1303204 Ref: option_mysqld_enable-pstack1304007 Ref: option_mysqld_engine-condition-pushdown1304617 Ref: option_mysqld_event-scheduler1305705 Ref: option_mysqld_exit-info1306839 Ref: option_mysqld_external-locking1307501 Ref: option_mysqld_flush1308569 Ref: option_mysqld_gdb1309343 Ref: option_mysqld_general-log1309995 Ref: option_mysqld_init-file1310943 Ref: option_mysqld_install1311970 Ref: option_mysqld_install-manual1312380 Ref: option_mysqld_language1312853 Ref: option_mysqld_large-pages1313982 Ref: option_mysqld_log1315273 Ref: option_mysqld_log-error1316897 Ref: option_mysqld_log-isam1317761 Ref: option_mysqld_log-long-format1318266 Ref: option_mysqld_log-output1319075 Ref: option_mysqld_log-queries-not-using-indexes1321195 Ref: option_mysqld_log-short-format1322276 Ref: option_mysqld_log-slow-admin-statements1322877 Ref: option_mysqld_log-slow-queries1323544 Ref: option_mysqld_log-tc1325279 Ref: option_mysqld_log-tc-size1326053 Ref: option_mysqld_log-warnings1326986 Ref: option_mysqld_low-priority-updates1328982 Ref: option_mysqld_min-examined-row-limit1330243 Ref: option_mysqld_memlock1331540 Ref: option_mysqld_myisam-block-size1333283 Ref: option_mysqld_myisam-recover1333829 Ref: option_mysqld_old-alter-table1336368 Ref: option_mysqld_old-passwords1337494 Ref: option_mysqld_old-style-user-limits1338398 Ref: option_mysqld_one-thread1339091 Ref: option_mysqld_open-files-limit1339643 Ref: option_mysqld_partition1341064 Ref: option_mysqld_pid-file1341843 Ref: option_mysqld_plugin1342789 Ref: option_mysqld_plugin-load1344093 Ref: option_mysqld_port1346463 Ref: option_mysqld_port-open-timeout1347308 Ref: option_mysqld_remove1348200 Ref: option_mysqld_safe-mode1348544 Ref: option_mysqld_safe-show-database1348811 Ref: option_mysqld_safe-user-create1349699 Ref: option_mysqld_secure-auth1350793 Ref: option_mysqld_secure-file-priv1351541 Ref: option_mysqld_shared-memory1352495 Ref: option_mysqld_shared-memory-base-name1352624 Ref: option_mysqld_skip-concurrent-insert1352843 Ref: option_mysqld_skip-external-locking1353081 Ref: option_mysqld_skip-event-scheduler1353433 Ref: option_mysqld_skip-grant-tables1353946 Ref: option_mysqld_skip-host-cache1354945 Ref: option_mysqld_skip-name-resolve1355423 Ref: option_mysqld_skip-networking1355680 Ref: option_mysqld_skip-partition1356020 Ref: option_mysqld_standalone1356630 Ref: option_mysqld_symbolic-links1356954 Ref: option_mysqld_skip-safemalloc1357989 Ref: option_mysqld_skip-show-database1358508 Ref: option_mysqld_skip-stack-trace1359484 Ref: option_mysqld_skip-thread-priority1359988 Ref: option_mysqld_slow-query-log1360880 Ref: option_mysqld_socket1361846 Ref: option_mysqld_sql-mode1363006 Ref: option_mysqld_sysdate-is-now1364951 Ref: option_mysqld_tc-heuristic-recover1365943 Ref: option_mysqld_temp-pool1366571 Ref: option_mysqld_transaction-isolation1367459 Ref: option_mysqld_tmpdir1368565 Ref: option_mysqld_user1370265 Ref: option_mysqld_verbose1371966 Ref: option_mysqld_version1372057 Node: server-system-variables1373130 Ref: sysvar_autocommit1410289 Ref: sysvar_automatic_sp_privileges1411957 Ref: sysvar_back_log1413177 Ref: sysvar_basedir1414816 Ref: sysvar_big_tables1415678 Ref: sysvar_bulk_insert_buffer_size1416265 Ref: sysvar_character_set_client1417833 Ref: sysvar_character_set_connection1419647 Ref: sysvar_character_set_database1420263 Ref: sysvar_character_set_filesystem1421880 Ref: sysvar_character_set_results1423395 Ref: sysvar_character_set_server1423943 Ref: sysvar_character_set_system1424674 Ref: sysvar_character_sets_dir1425163 Ref: sysvar_collation_connection1425908 Ref: sysvar_collation_database1426391 Ref: sysvar_collation_server1427988 Ref: sysvar_completion_type1428691 Ref: sysvar_concurrent_insert1430460 Ref: sysvar_connect_timeout1432050 Ref: sysvar_datadir1433427 Ref: sysvar_date_format1434177 Ref: sysvar_datetime_format1434229 Ref: sysvar_debug1434285 Ref: sysvar_debug_sync1435951 Ref: sysvar_default_week_format1437647 Ref: sysvar_delay_key_write1438524 Ref: sysvar_delayed_insert_limit1440568 Ref: sysvar_delayed_insert_timeout1441960 Ref: sysvar_delayed_queue_size1442826 Ref: sysvar_div_precision_increment1444217 Ref: sysvar_engine_condition_pushdown1445707 Ref: sysvar_error_count1447635 Ref: sysvar_event_scheduler1447809 Ref: sysvar_expire_logs_days1449029 Ref: sysvar_flush1450152 Ref: sysvar_flush_time1451050 Ref: sysvar_foreign_key_checks1452241 Ref: sysvar_ft_boolean_syntax1453197 Ref: sysvar_ft_max_word_len1454653 Ref: sysvar_ft_min_word_len1455520 Ref: sysvar_ft_query_expansion_limit1456430 Ref: sysvar_ft_stopword_file1457296 Ref: sysvar_general_log1458673 Ref: sysvar_general_log_file1459834 Ref: sysvar_group_concat_max_len1460848 Ref: sysvar_have_archive1462107 Ref: sysvar_have_blackhole_engine1462256 Ref: sysvar_have_compress1462416 Ref: sysvar_have_community_features1462606 Ref: sysvar_have_crypt1462795 Ref: sysvar_have_csv1462951 Ref: sysvar_have_dynamic_loading1463166 Ref: sysvar_have_example_engine1463331 Ref: sysvar_have_federated_engine1463487 Ref: sysvar_have_geometry1463647 Ref: sysvar_have_innodb1463738 Ref: sysvar_have_isam1463985 Ref: sysvar_have_merge_engine1464207 Ref: sysvar_have_openssl1464388 Ref: sysvar_have_partitioning1464555 Ref: sysvar_have_query_cache1464862 Ref: sysvar_have_row_based_replication1464971 Ref: sysvar_have_raid1465726 Ref: sysvar_have_rtree_keys1465948 Ref: sysvar_have_ssl1466094 Ref: sysvar_have_symlink1466478 Ref: sysvar_hostname1466730 Ref: sysvar_identity1467242 Ref: sysvar_init_connect1467482 Ref: sysvar_init_file1469302 Ref: sysvar_insert_id1470601 Ref: sysvar_interactive_timeout1470828 Ref: sysvar_join_buffer_size1471891 Ref: sysvar_keep_files_on_create1473671 Ref: sysvar_key_buffer_size1475267 Ref: sysvar_key_cache_age_threshold1480395 Ref: sysvar_key_cache_block_size1481777 Ref: sysvar_key_cache_division_limit1482629 Ref: sysvar_language1483664 Ref: sysvar_large_files_support1484638 Ref: sysvar_large_pages1484941 Ref: sysvar_large_page_size1485735 Ref: sysvar_last_insert_id1486394 Ref: sysvar_lc_time_names1486720 Ref: sysvar_license1487667 Ref: sysvar_local_infile1488100 Ref: sysvar_locked_in_memory1488586 Ref: sysvar_log1488869 Ref: sysvar_log_bin1489101 Ref: sysvar_log_bin_trust_function_creators1489614 Ref: sysvar_log_error1491192 Ref: sysvar_log_output1491859 Ref: sysvar_log_queries_not_using_indexes1493305 Ref: sysvar_log_slave_updates1494165 Ref: sysvar_log_slow_queries1494440 Ref: sysvar_log_warnings1495519 Ref: sysvar_long_query_time1496829 Ref: sysvar_low_priority_updates1498411 Ref: sysvar_lower_case_file_system1499578 Ref: sysvar_lower_case_table_names1500593 Ref: sysvar_max_allowed_packet1502916 Ref: sysvar_max_connect_errors1504952 Ref: sysvar_max_connections1506579 Ref: sysvar_max_delayed_threads1508309 Ref: sysvar_max_error_count1509634 Ref: sysvar_max_heap_table_size1510575 Ref: sysvar_max_insert_delayed_threads1512486 Ref: sysvar_max_join_size1512995 Ref: sysvar_max_length_for_sort_data1514786 Ref: sysvar_max_long_data_size1515727 Ref: sysvar_max_prepared_stmt_count1516913 Ref: sysvar_max_relay_log_size1518411 Ref: sysvar_max_seeks_for_key1519805 Ref: sysvar_max_sort_length1521398 Ref: sysvar_max_sp_recursion_depth1522341 Ref: sysvar_max_tmp_tables1523615 Ref: sysvar_max_user_connections1524859 Ref: sysvar_max_write_lock_count1526514 Ref: sysvar_min_examined_row_limit1527743 Ref: sysvar_myisam_data_pointer_size1528985 Ref: sysvar_myisam_max_sort_file_size1530012 Ref: sysvar_myisam_mmap_size1531414 Ref: sysvar_myisam_recover_options1532860 Ref: sysvar_myisam_repair_threads1533162 Ref: sysvar_myisam_sort_buffer_size1534578 Ref: sysvar_myisam_stats_method1536239 Ref: sysvar_myisam_use_mmap1537934 Ref: sysvar_named_pipe1538748 Ref: sysvar_net_buffer_length1539287 Ref: sysvar_net_read_timeout1540840 Ref: sysvar_net_retry_count1542277 Ref: sysvar_net_write_timeout1544032 Ref: sysvar_new1545247 Ref: sysvar_old1546144 Ref: sysvar_old_alter_table1547263 Ref: sysvar_old_passwords1548391 Ref: sysvar_one_shot1549196 Ref: sysvar_open_files_limit1549336 Ref: sysvar_optimizer_prune_level1550441 Ref: sysvar_optimizer_search_depth1551535 Ref: sysvar_optimizer_switch1552958 Ref: sysvar_pid_file1554516 Ref: sysvar_plugin_dir1555263 Ref: sysvar_port1556841 Ref: sysvar_preload_buffer_size1557623 Ref: sysvar_prepared_stmt_count1558476 Ref: sysvar_profiling1558796 Ref: sysvar_profiling_history_size1559151 Ref: sysvar_protocol_version1559480 Ref: sysvar_pseudo_thread_id1559930 Ref: sysvar_query_alloc_block_size1560354 Ref: sysvar_query_cache_limit1561832 Ref: sysvar_query_cache_min_res_unit1563021 Ref: sysvar_query_cache_size1564355 Ref: sysvar_query_cache_type1566118 Ref: sysvar_query_cache_wlock_invalidate1567822 Ref: sysvar_query_prealloc_size1569084 Ref: sysvar_rand_seed11570695 Ref: sysvar_rand_seed21571386 Ref: sysvar_range_alloc_block_size1571450 Ref: sysvar_read_buffer_size1572415 Ref: sysvar_read_only1573844 Ref: sysvar_read_rnd_buffer_size1577282 Ref: sysvar_relay_log_purge1578828 Ref: sysvar_relay_log_space_limit1579628 Ref: sysvar_report_host1580799 Ref: sysvar_report_password1581494 Ref: sysvar_report_port1582287 Ref: sysvar_report_user1583018 Ref: sysvar_secure_auth1583708 Ref: sysvar_secure_file_priv1584916 Ref: sysvar_server_id1585923 Ref: sysvar_shared_memory1586899 Ref: sysvar_shared_memory_base_name1587215 Ref: sysvar_skip_external_locking1587721 Ref: sysvar_skip_name_resolve1587942 Ref: sysvar_skip_networking1588367 Ref: sysvar_skip_show_database1588769 Ref: sysvar_slow_launch_time1589564 Ref: sysvar_slow_query_log1590366 Ref: sysvar_slow_query_log_file1590892 Ref: sysvar_socket1591891 Ref: sysvar_sort_buffer_size1592983 Ref: sysvar_sql_auto_is_null1595431 Ref: sysvar_sql_big_selects1596577 Ref: sysvar_sql_buffer_result1597561 Ref: sysvar_sql_log_bin1598287 Ref: sysvar_sql_log_off1598817 Ref: sysvar_sql_log_update1599398 Ref: sysvar_sql_mode1600002 Ref: sysvar_sql_notes1601966 Ref: sysvar_sql_quote_show_create1602321 Ref: sysvar_sql_safe_updates1602756 Ref: sysvar_sql_select_limit1603182 Ref: sysvar_sql_warnings1604642 Ref: sysvar_ssl_ca1604877 Ref: sysvar_ssl_capath1605633 Ref: sysvar_ssl_cert1606443 Ref: sysvar_ssl_cipher1607242 Ref: sysvar_ssl_key1608028 Ref: sysvar_storage_engine1608770 Ref: sysvar_sync_frm1609181 Ref: sysvar_system_time_zone1610015 Ref: sysvar_table_cache1611115 Ref: sysvar_table_definition_cache1612144 Ref: sysvar_table_lock_wait_timeout1613791 Ref: sysvar_table_open_cache1614581 Ref: sysvar_table_type1615937 Ref: sysvar_thread_cache_size1616654 Ref: sysvar_thread_concurrency1618330 Ref: sysvar_thread_handling1619361 Ref: sysvar_thread_stack1620300 Ref: sysvar_time_format1621908 Ref: sysvar_time_zone1621960 Ref: sysvar_timed_mutexes1622886 Ref: sysvar_timestamp1623980 Ref: sysvar_tmp_table_size1624611 Ref: sysvar_tmpdir1626220 Ref: sysvar_transaction_alloc_block_size1628007 Ref: sysvar_transaction_allow_batching1629453 Ref: sysvar_transaction_prealloc_size1630341 Ref: sysvar_tx_isolation1632241 Ref: sysvar_unique_checks1633685 Ref: sysvar_updatable_views_with_limit1634689 Ref: sysvar_version1636121 Ref: sysvar_version_comment1636465 Ref: sysvar_version_compile_machine1637016 Ref: sysvar_version_compile_os1637480 Ref: sysvar_wait_timeout1637922 Ref: sysvar_warning_count1639531 Node: using-system-variables1639725 Node: structured-system-variables1651994 Node: dynamic-system-variables1657169 Node: server-status-variables1675531 Ref: statvar_Aborted_clients1705190 Ref: statvar_Aborted_connects1705374 Ref: statvar_Binlog_cache_disk_use1705508 Ref: statvar_Binlog_cache_use1705742 Ref: statvar_Bytes_received1705848 Ref: statvar_Bytes_sent1705925 Ref: statvar_Com_xxx1705992 Ref: statvar_Compression1708324 Ref: statvar_Connections1708456 Ref: statvar_Created_tmp_disk_tables1708563 Ref: statvar_Created_tmp_files1709544 Ref: statvar_Created_tmp_tables1709639 Ref: statvar_Delayed_errors1710231 Ref: statvar_Delayed_insert_threads1710401 Ref: statvar_Delayed_writes1710523 Ref: statvar_Flush_commands1710627 Ref: statvar_Handler_commit1710715 Ref: statvar_Handler_delete1710805 Ref: statvar_Handler_prepare1710896 Ref: statvar_Handler_read_first1710991 Ref: statvar_Handler_read_key1711255 Ref: statvar_Handler_read_next1711453 Ref: statvar_Handler_read_prev1711675 Ref: statvar_Handler_read_rnd1711840 Ref: statvar_Handler_read_rnd_next1712170 Ref: statvar_Handler_rollback1712493 Ref: statvar_Handler_savepoint1712607 Ref: statvar_Handler_savepoint_rollback1712706 Ref: statvar_Handler_update1712826 Ref: statvar_Handler_write1712907 Ref: statvar_Innodb_buffer_pool_pages_data1712987 Ref: statvar_Innodb_buffer_pool_pages_dirty1713086 Ref: statvar_Innodb_buffer_pool_pages_flushed1713169 Ref: statvar_Innodb_buffer_pool_pages_free1713264 Ref: statvar_Innodb_buffer_pool_pages_latched1713335 Ref: statvar_Innodb_buffer_pool_pages_misc1713714 Ref: statvar_Innodb_buffer_pool_pages_total1714059 Ref: statvar_Innodb_buffer_pool_read_ahead1714150 Ref: statvar_Innodb_buffer_pool_read_ahead_evicted1714362 Ref: statvar_Innodb_buffer_pool_read_ahead_rnd1714658 Ref: statvar_Innodb_buffer_pool_read_ahead_seq1714925 Ref: statvar_Innodb_buffer_pool_read_requests1715171 Ref: statvar_Innodb_buffer_pool_reads1715274 Ref: statvar_Innodb_buffer_pool_wait_free1715441 Ref: statvar_Innodb_buffer_pool_write_requests1715849 Ref: statvar_Innodb_data_fsyncs1715950 Ref: statvar_Innodb_data_pending_fsyncs1716027 Ref: statvar_Innodb_data_pending_reads1716121 Ref: statvar_Innodb_data_pending_writes1716199 Ref: statvar_Innodb_data_read1716279 Ref: statvar_Innodb_data_reads1716365 Ref: statvar_Innodb_data_writes1716430 Ref: statvar_Innodb_data_written1716497 Ref: statvar_Innodb_dblwr_pages_written1716577 Ref: statvar_Innodb_dblwr_writes1716723 Ref: statvar_Innodb_have_atomic_builtins1716854 Ref: statvar_Innodb_log_waits1717034 Ref: statvar_Innodb_log_write_requests1717189 Ref: statvar_Innodb_log_writes1717264 Ref: statvar_Innodb_os_log_fsyncs1717344 Ref: statvar_Innodb_os_log_pending_fsyncs1717433 Ref: statvar_Innodb_os_log_pending_writes1717530 Ref: statvar_Innodb_os_log_written1717613 Ref: statvar_Innodb_page_size1717695 Ref: statvar_Innodb_pages_created1717882 Ref: statvar_Innodb_pages_read1717947 Ref: statvar_Innodb_pages_written1718006 Ref: statvar_Innodb_row_lock_current_waits1718071 Ref: statvar_Innodb_row_lock_time1718168 Ref: statvar_Innodb_row_lock_time_avg1718266 Ref: statvar_Innodb_row_lock_time_max1718363 Ref: statvar_Innodb_row_lock_waits1718460 Ref: statvar_Innodb_rows_deleted1718550 Ref: statvar_Innodb_rows_inserted1718634 Ref: statvar_Innodb_rows_read1718720 Ref: statvar_Innodb_rows_updated1718798 Ref: statvar_Key_blocks_not_flushed1718880 Ref: statvar_Key_blocks_unused1719022 Ref: statvar_Key_blocks_used1719260 Ref: statvar_Key_read_requests1719461 Ref: statvar_Key_reads1719553 Ref: statvar_Key_write_requests1719804 Ref: statvar_Key_writes1719896 Ref: statvar_Last_query_cost1719976 Ref: statvar_Max_used_connections1720537 Ref: statvar_Not_flushed_delayed_rows1720675 Ref: statvar_Open_files1720812 Ref: statvar_Open_streams1721162 Ref: statvar_Open_table_definitions1721253 Ref: statvar_Open_tables1721371 Ref: statvar_Opened_files1721434 Ref: statvar_Opened_table_definitions1721699 Ref: statvar_Opened_tables1721835 Ref: statvar_Prepared_stmt_count1721993 Ref: statvar_Qcache_free_blocks1722216 Ref: statvar_Qcache_free_memory1722303 Ref: statvar_Qcache_hits1722384 Ref: statvar_Qcache_inserts1722443 Ref: statvar_Qcache_lowmem_prunes1722521 Ref: statvar_Qcache_not_cached1722646 Ref: statvar_Qcache_queries_in_cache1722786 Ref: statvar_Qcache_total_blocks1722878 Ref: statvar_Queries1722960 Ref: statvar_Questions1723247 Ref: statvar_Rpl_status1723651 Ref: statvar_Select_full_join1723790 Ref: statvar_Select_full_range_join1723989 Ref: statvar_Select_range1724094 Ref: statvar_Select_range_check1724256 Ref: statvar_Select_scan1724447 Ref: statvar_Slave_open_temp_tables1724535 Ref: statvar_Slave_retried_transactions1724779 Ref: statvar_Slave_running1724930 Ref: statvar_Slow_launch_threads1725133 Ref: statvar_Slow_queries1725259 Ref: statvar_Sort_merge_passes1725395 Ref: statvar_Sort_range1725612 Ref: statvar_Sort_rows1725687 Ref: statvar_Sort_scan1725739 Ref: statvar_Ssl_accept_renegotiates1725822 Ref: statvar_Ssl_accepts1725922 Ref: statvar_Ssl_callback_cache_hits1725989 Ref: statvar_Ssl_cipher1726063 Ref: statvar_Ssl_cipher_list1726145 Ref: statvar_Ssl_client_connects1726210 Ref: statvar_Ssl_connect_renegotiates1726309 Ref: statvar_Ssl_ctx_verify_depth1726440 Ref: statvar_Ssl_ctx_verify_mode1726565 Ref: statvar_Ssl_default_timeout1726635 Ref: statvar_Ssl_finished_accepts1726695 Ref: statvar_Ssl_finished_connects1726787 Ref: statvar_Ssl_session_cache_hits1726898 Ref: statvar_Ssl_session_cache_misses1726974 Ref: statvar_Ssl_session_cache_mode1727054 Ref: statvar_Ssl_session_cache_overflows1727120 Ref: statvar_Ssl_session_cache_size1727206 Ref: statvar_Ssl_session_cache_timeouts1727272 Ref: statvar_Ssl_sessions_reused1727356 Ref: statvar_Ssl_used_session_cache_entries1727444 Ref: statvar_Ssl_verify_depth1727536 Ref: statvar_Ssl_verify_mode1727624 Ref: statvar_Ssl_version1727710 Ref: statvar_Table_locks_immediate1727781 Ref: statvar_Table_locks_waited1727905 Ref: statvar_Tc_log_max_pages_used1728216 Ref: statvar_Tc_log_page_size1729062 Ref: statvar_Tc_log_page_waits1729342 Ref: statvar_Threads_cached1729911 Ref: statvar_Threads_connected1729984 Ref: statvar_Threads_created1730059 Ref: statvar_Threads_running1730317 Ref: statvar_Uptime1730393 Ref: statvar_Uptime_since_flush_status1730466 Node: server-sql-mode1730612 Ref: sqlmode_allow_invalid_dates1734260 Ref: sqlmode_ansi_quotes1735219 Ref: sqlmode_error_for_division_by_zero1735586 Ref: sqlmode_high_not_precedence1736048 Ref: sqlmode_ignore_space1736660 Ref: sqlmode_no_auto_create_user1737679 Ref: sqlmode_no_auto_value_on_zero1737881 Ref: sqlmode_no_backslash_escapes1738898 Ref: sqlmode_no_dir_in_create1739114 Ref: sqlmode_no_engine_substitution1739293 Ref: sqlmode_no_field_options1740704 Ref: sqlmode_no_key_options1740924 Ref: sqlmode_no_table_options1741141 Ref: sqlmode_no_unsigned_subtraction1741379 Ref: sqlmode_no_zero_date1743488 Ref: sqlmode_no_zero_in_date1743720 Ref: sqlmode_only_full_group_by1744123 Ref: sqlmode_pad_char_to_full_length1744637 Ref: sqlmode_pipes_as_concat1746045 Ref: sqlmode_real_as_float1746183 Ref: sqlmode_strict_all_tables1746406 Ref: sqlmode_strict_trans_tables1746549 Ref: sqlmode_ansi1749642 Ref: sqlmode_db21750493 Ref: sqlmode_maxdb1750639 Ref: sqlmode_mssql1750815 Ref: sqlmode_mysql3231750963 Ref: sqlmode_mysql401751044 Ref: sqlmode_oracle1751124 Ref: sqlmode_postgresql1751301 Ref: sqlmode_traditional1751454 Node: server-plugins1751632 Node: server-plugin-loading1752299 Ref: server-plugin-installing1752856 Ref: server-plugin-activating1757055 Ref: server-plugin-uninstalling1760618 Node: obtaining-plugin-information1761591 Node: server-side-help-support1764317 Node: server-signal-response1765995 Node: server-shutdown1767774 Node: server-logs1771831 Node: log-destinations1774521 Node: error-log1783558 Node: query-log1789345 Node: binary-log1793727 Node: binary-log-formats1807252 Node: binary-log-setting1809635 Node: binary-log-mixed1814221 Node: binary-log-mysql-database1824310 Node: slow-query-log1826062 Node: log-file-maintenance1830730 Node: security1835341 Node: security-guidelines1836356 Node: password-security1845680 Node: password-security-admin1846470 Node: password-security-user1848209 Node: password-hashing1853070 Node: application-password-use1867030 Node: security-against-attack1868506 Node: privileges-options1875379 Ref: option_mysqld_local-infile1878463 Ref: option_mysqld_skip-merge1881186 Ref: option_mysqld_ssl_xxxx1882160 Node: load-data-local1882353 Node: changing-mysql-user1885741 Node: privilege-system1888059 Node: privileges-provided1892633 Ref: priv_all1897139 Ref: priv_alter1897440 Ref: priv_alter-routine1897772 Ref: priv_create1897885 Ref: priv_create-routine1897966 Ref: priv_create-temporary-tables1898073 Ref: priv_create-user1898924 Ref: priv_create-view1899125 Ref: priv_delete1899214 Ref: priv_drop1899303 Ref: priv_event1899937 Ref: priv_execute1900087 Ref: priv_file1900190 Ref: priv_grant-option1900912 Ref: priv_index1901064 Ref: priv_insert1901329 Ref: priv_lock-tables1901612 Ref: priv_process1901892 Ref: priv_references1902302 Ref: priv_reload1902357 Ref: priv_replication-client1903172 Ref: priv_replication-slave1903341 Ref: priv_select1903620 Ref: priv_show-databases1904520 Ref: priv_show-view1904933 Ref: priv_shutdown1905030 Ref: priv_super1905183 Ref: priv_trigger1906217 Ref: priv_update1906501 Ref: priv_usage1906588 Node: grant-table-structure1908483 Node: account-names1922134 Node: connection-access1927513 Node: request-access1935760 Node: privilege-changes1944418 Node: access-denied1946731 Node: user-account-management1965254 Node: user-names1966540 Node: adding-users1971547 Node: removing-users1983508 Node: user-resources1983798 Node: assigning-passwords1991395 Node: secure-connections1996264 Node: secure-basics1998004 Node: secure-using-ssl2000315 Node: ssl-options2007364 Ref: option_general_ssl2009676 Ref: option_general_ssl-ca2011079 Ref: option_general_ssl-capath2011173 Ref: option_general_ssl-cert2011302 Ref: option_general_ssl-cipher2011425 Ref: option_general_ssl-key2012157 Ref: option_general_ssl-verify-server-cert2012271 Node: secure-create-certs2013221 Node: windows-and-ssh2026006 Node: account-activity-auditing2027756 Node: multiple-servers2032867 Node: multiple-data-directories2038068 Node: multiple-windows-servers2041401 Node: multiple-windows-command-line-servers2042390 Node: multiple-windows-services2045510 Node: multiple-unix-servers2049862 Node: multiple-server-clients2053796 Node: backup-and-recovery2056582 Node: backup-types2059751 Node: backup-methods2069785 Node: backup-strategy-example2077075 Node: backup-policy2080575 Node: recovery-from-backups2087834 Node: backup-strategy-summary2089866 Node: using-mysqldump2090912 Node: mysqldump-sql-format2093056 Node: reloading-sql-format-dumps2096114 Node: mysqldump-delimited-text2097422 Node: reloading-delimited-text-dumps2101680 Node: mysqldump-tips2103292 Node: mysqldump-copying-database2104180 Node: mysqldump-copying-to-other-server2104725 Node: mysqldump-stored-programs2105978 Node: mysqldump-definition-data-dumps2106848 Node: mysqldump-upgrade-testing2107868 Node: point-in-time-recovery2109224 Node: point-in-time-recovery-times2113978 Node: point-in-time-recovery-positions2116126 Node: myisam-table-maintenance2118478 Node: myisam-crash-recovery2121164 Node: myisam-check2124701 Node: myisam-repair2126554 Node: myisam-optimization2134252 Node: myisam-maintenance-schedule2135899 Node: optimization2138385 Node: optimize-overview2139530 Node: design-limitations2141335 Node: portability2143090 Node: mysql-benchmarks2147049 Node: custom-benchmarks2149449 Node: execution-plan-information2151587 Node: using-explain2152010 Node: explain-output2154342 Ref: jointype_system2158393 Ref: jointype_const2158529 Ref: jointype_eq_ref2159234 Ref: jointype_ref2160214 Ref: jointype_fulltext2161243 Ref: jointype_ref_or_null2161325 Ref: jointype_index_merge2161827 Ref: jointype_unique_subquery2162191 Ref: jointype_index_subquery2162528 Ref: jointype_range2162816 Ref: jointype_index2163700 Ref: jointype_all2164044 Node: estimating-performance2184327 Node: statement-optimization2186130 Node: select-optimization2186601 Node: select-speed2189464 Node: where-optimizations2191211 Node: range-optimization2195942 Node: range-access-single-part2196616 Node: range-access-multi-part2201090 Node: index-merge-optimization2206374 Node: index-merge-intersection2209234 Node: index-merge-union2210887 Node: index-merge-sort-union2211942 Node: condition-pushdown-optimization2212704 Node: is-null-optimization2217304 Node: left-join-optimization2219459 Node: nested-loop-joins2222444 Node: nested-join-optimization2226161 Node: outer-join-simplification2239895 Node: order-by-optimization2245662 Node: group-by-optimization2254849 Node: loose-index-scan2256433 Node: tight-index-scan2260146 Node: distinct-optimization2262260 Node: in-subquery-optimization2263796 Node: limit-optimization2276310 Node: how-to-avoid-table-scan2278593 Node: non-select-optimization2280578 Node: insert-speed2281075 Node: update-speed2287807 Node: delete-speed2288706 Node: repair-table-speed2289427 Node: information-schema-optimization2294242 Node: miscellaneous-optimization-tips2309469 Node: controlling-optimizer2320422 Node: controlling-query-plan-evaluation2320927 Node: switchable-optimizations2323980 Node: optimization-indexes2327658 Node: column-indexes2328083 Node: multiple-column-indexes2330217 Node: mysql-indexes2332198 Node: myisam-index-statistics2340932 Node: buffering-caching2346868 Node: myisam-key-cache2347315 Node: shared-key-cache2351197 Node: multiple-key-caches2352024 Node: midpoint-insertion2357520 Node: index-preloading2360067 Node: key-cache-block-size2361876 Node: key-cache-restructuring2362799 Node: innodb-buffer-pool2364178 Node: query-cache2372798 Node: query-cache-operation2376922 Node: query-cache-in-select2383109 Node: query-cache-configuration2383724 Node: query-cache-status-and-maintenance2390049 Node: locking-issues2392892 Node: internal-locking2393881 Node: table-locking2401326 Node: concurrent-inserts2406598 Node: external-locking2409542 Node: optimizing-database-structure2414153 Node: data-size2414665 Node: table-cache2419650 Node: creating-many-tables2425133 Node: internal-temporary-tables2425815 Node: optimizing-the-server2428757 Node: system-optimization2429448 Node: server-parameters2432058 Node: connection-threads2448498 Node: memory-use2451760 Node: disk-issues2457607 Node: symbolic-links2461744 Node: symbolic-links-to-databases2462597 Node: symbolic-links-to-tables2463998 Node: windows-symbolic-links2468478 Node: large-page-support2470717 Node: dns2475404 Node: thread-information2477313 Node: thread-commands2480390 Node: general-thread-states2482974 Node: delayed-insert-thread-states2495639 Node: query-cache-thread-states2498759 Node: master-thread-states2499723 Node: slave-io-thread-states2501041 Node: slave-sql-thread-states2504346 Node: slave-connection-thread-states2505690 Node: mysql-cluster-thread-states2507067 Node: event-scheduler-thread-states2508149 Node: language-structure2509097 Node: literals2509845 Node: string-syntax2510605 Node: number-syntax2517239 Node: date-and-time-values2517838 Node: hexadecimal-values2518534 Node: boolean-values2520146 Node: bit-field-values2520499 Node: null-values2522067 Node: identifiers2522686 Node: identifier-qualifiers2528749 Node: identifier-case-sensitivity2530903 Node: identifier-mapping2537285 Node: function-resolution2543730 Node: reserved-words2554334 Node: user-variables2561699 Node: expressions2569708 Node: comments2573676 Node: globalization2576533 Node: charset2577623 Node: charset-general2580017 Node: charset-mysql2582704 Node: charset-syntax2588024 Node: charset-server2589723 Node: charset-database2591896 Node: charset-table2594379 Node: charset-column2596039 Node: charset-literal2599385 Node: charset-national2604150 Node: charset-examples2605207 Node: charset-compatibility2607502 Node: charset-connection2607838 Node: charset-applications2615604 Node: charset-errors2621110 Node: charset-collations2622679 Node: charset-collation-names2623522 Node: charset-collate2624011 Node: charset-collate-precedence2625347 Node: charset-collation-charset2625719 Node: charset-collation-expressions2626389 Node: charset-binary-collations2630393 Node: charset-binary-op2636183 Node: charset-collation-effect2638322 Node: charset-collation-information-schema2641354 Node: charset-repertoire2646379 Node: charset-operations2651326 Node: charset-result2651821 Node: charset-convert2654817 Node: charset-show2656303 Node: charset-unicode2661349 Node: charset-unicode-ucs22663660 Node: charset-unicode-utf82664425 Node: charset-metadata2665979 Node: charset-conversion2670150 Node: charset-charsets2674222 Node: charset-unicode-sets2678551 Node: charset-we-sets2683526 Node: charset-ce-sets2687272 Node: charset-se-me-sets2688863 Node: charset-baltic-sets2690465 Node: charset-cyrillic-sets2691291 Node: charset-asian-sets2692540 Node: charset-cp9322694979 Node: error-message-language2701525 Node: adding-character-set2703094 Node: character-arrays2710493 Node: string-collating2713661 Node: multi-byte-characters2714705 Node: adding-collation2715576 Node: charset-collation-implementations2718753 Node: adding-collation-choosing-id2722842 Node: adding-collation-simple-8bit2725083 Node: adding-collation-unicode-uca2728895 Node: ldml-collation-example2730390 Node: ldml-rules2736301 Node: charset-configuration2738813 Node: time-zone-support2742110 Node: time-zone-upgrades2749726 Node: time-zone-leap-seconds2755251 Node: locale-support2757789 Node: data-types2764641 Node: data-type-overview2766569 Node: numeric-type-overview2766974 Node: date-and-time-type-overview2777375 Node: string-type-overview2781479 Node: data-type-defaults2792826 Node: numeric-types2796517 Node: date-and-time-types2807265 Node: datetime2812837 Node: timestamp2822458 Node: time2832816 Node: year2836413 Node: y2k-issues2838172 Node: string-types2840988 Node: char2841812 Node: binary-varbinary2847457 Node: blob2851912 Node: enum2858496 Node: set2864978 Node: storage-requirements2871036 Node: out-of-range-and-overflow2883742 Node: choosing-types2888172 Node: other-vendor-data-types2889382 Node: functions2891997 Node: func-op-summary-ref2895285 Node: type-conversion2914690 Node: non-typed-operators2919627 Node: operator-precedence2922401 Node: comparison-operators2924205 Ref: operator_equal2927160 Ref: operator_equal-to2927473 Ref: operator_not-equal2927891 Ref: operator_less-than-or-equal2928119 Ref: operator_less-than2928215 Ref: operator_greater-than-or-equal2928298 Ref: operator_greater-than2928395 Ref: operator_is2928481 Ref: operator_is-not2928709 Ref: operator_is-null2928958 Ref: operator_is-not-null2930775 Ref: operator_between2930941 Ref: operator_not-between2932239 Ref: function_coalesce2932337 Ref: function_greatest2932612 Ref: function_in2933083 Ref: function_not-in2934664 Ref: function_isnull2934752 Ref: function_interval2935264 Ref: function_least2935808 Node: logical-operators2937348 Ref: operator_not2938297 Ref: operator_and2938824 Ref: operator_or2939291 Ref: operator_xor2939878 Node: assignment-operators2940392 Ref: operator_assign-value2940928 Ref: operator_assign-equal2942983 Node: control-flow-functions2944722 Ref: operator_case2945178 Ref: function_if2946733 Ref: function_ifnull2948012 Ref: function_nullif2949373 Node: string-functions2949758 Ref: function_ascii2955117 Ref: function_bin2955554 Ref: function_bit-length2955839 Ref: function_char2955985 Ref: function_char-length2957923 Ref: function_character-length2958213 Ref: function_concat2958305 Ref: function_concat-ws2959285 Ref: function_elt2960068 Ref: function_export-set2960465 Ref: function_field2961371 Ref: function_find-in-set2962087 Ref: function_format2962812 Ref: function_hex2963271 Ref: function_insert2964032 Ref: function_instr2964766 Ref: function_lcase2965262 Ref: function_left2965326 Ref: function_length2965530 Ref: function_load-file2965870 Ref: function_locate2966791 Ref: function_lower2967468 Ref: function_lpad2968484 Ref: function_ltrim2968836 Ref: function_make-set2969038 Ref: function_mid2969723 Ref: function_octet-length2969817 Ref: function_ord2969896 Ref: function_position2970406 Ref: function_quote2970510 Ref: function_repeat2971093 Ref: function_replace2971381 Ref: function_reverse2971749 Ref: function_right2971951 Ref: function_rpad2972197 Ref: function_rtrim2972589 Ref: function_soundex2972793 Ref: operator_sounds-like2974355 Ref: function_space2974449 Ref: function_substr2974589 Ref: function_substring2974747 Ref: function_substring-index2976174 Ref: function_trim2976867 Ref: function_ucase2977576 Ref: function_unhex2977640 Ref: function_upper2979459 Node: string-comparison-functions2980080 Ref: operator_like2980848 Ref: operator_not-like2986208 Ref: function_strcmp2987274 Node: regexp2989068 Ref: operator_not-regexp2990179 Ref: operator_regexp2990281 Node: numeric-functions3003412 Node: arithmetic-functions3006572 Ref: operator_plus3009004 Ref: operator_minus3009084 Ref: operator_unary-minus3009168 Ref: operator_times3009544 Ref: operator_divide3009751 Ref: operator_div3010109 Ref: operator_mod3010398 Node: mathematical-functions3010585 Ref: function_abs3013310 Ref: function_acos3013563 Ref: function_asin3013902 Ref: function_atan3014721 Ref: function_atan23014961 Ref: function_ceil3015368 Ref: function_ceiling3015430 Ref: function_conv3015820 Ref: function_cos3016658 Ref: function_cot3016794 Ref: function_crc323016974 Ref: function_degrees3017377 Ref: function_exp3017594 Ref: function_floor3017988 Ref: function_ln3018859 Ref: function_log3019259 Ref: function_log23020108 Ref: function_log103020453 Ref: function_mod3020755 Ref: function_oct3021387 Ref: function_pi3021669 Ref: function_pow3021999 Ref: function_power3022191 Ref: function_radians3022248 Ref: function_rand3022456 Ref: function_round3026368 Ref: function_sign3028770 Ref: function_sin3029082 Ref: function_sqrt3029298 Ref: function_tan3029561 Ref: function_truncate3029790 Node: date-and-time-functions3030495 Ref: function_adddate3037201 Ref: function_addtime3037958 Ref: function_convert-tz3038370 Ref: function_curdate3039611 Ref: function_current-date3039935 Ref: function_curtime3040047 Ref: function_current-time3040431 Ref: function_current-timestamp3040543 Ref: function_date3040676 Ref: function_datediff3040854 Ref: function_date-add3041305 Ref: function_date-format3048745 Ref: function_date-sub3052513 Ref: function_day3052600 Ref: function_dayname3052666 Ref: function_dayofmonth3052970 Ref: function_dayofweek3053236 Ref: function_dayofyear3053488 Ref: function_extract3053658 Ref: function_from-days3054294 Ref: function_from-unixtime3054649 Ref: function_get-format3055980 Ref: function_hour3057833 Ref: function_last-day3058226 Ref: function_localtime3058737 Ref: function_localtimestamp3058833 Ref: function_makedate3058949 Ref: function_maketime3059395 Ref: function_microsecond3059598 Ref: function_minute3059926 Ref: function_month3060088 Ref: function_monthname3060359 Ref: function_now3060670 Ref: function_period-add3062569 Ref: function_period-diff3062842 Ref: function_quarter3063137 Ref: function_second3063304 Ref: function_sec-to-time3063455 Ref: function_str-to-date3063925 Ref: function_subdate3066687 Ref: function_subtime3067453 Ref: function_sysdate3067898 Ref: function_time3070229 Ref: function_timediff3070739 Ref: function_timestamp3071265 Ref: function_timestampadd3071785 Ref: function_timestampdiff3072714 Ref: function_time-format3073729 Ref: function_time-to-sec3074345 Ref: function_to-days3074579 Ref: function_unix-timestamp3076815 Ref: function_utc-date3079676 Ref: function_utc-time3079975 Ref: function_utc-timestamp3080280 Ref: function_week3080652 Ref: function_weekday3083255 Ref: function_weekofyear3083523 Ref: function_year3083802 Ref: function_yearweek3083990 Node: mysql-calendar3084561 Node: fulltext-search3086479 Ref: function_match3087115 Node: fulltext-natural-language3090518 Node: fulltext-boolean3101443 Node: fulltext-query-expansion3108567 Node: fulltext-stopwords3111714 Node: fulltext-restrictions3119956 Node: fulltext-fine-tuning3121530 Node: full-text-adding-collation3129275 Node: cast-functions3133638 Ref: operator_binary3134066 Ref: function_cast3135057 Ref: function_convert3135267 Node: xml-functions3141285 Ref: function_extractvalue3147541 Ref: function_updatexml3153554 Node: bit-functions3174123 Ref: operator_bitwise-or3174797 Ref: operator_bitwise-and3174932 Ref: operator_bitwise-xor3175068 Ref: operator_left-shift3175310 Ref: operator_right-shift3175671 Ref: operator_bitwise-invert3176033 Ref: function_bit-count3176171 Node: encryption-functions3176341 Ref: function_aes-decrypt3180598 Ref: function_aes-encrypt3180809 Ref: function_compress3182300 Ref: function_decode3183788 Ref: function_des-decrypt3183963 Ref: function_des-encrypt3184869 Ref: function_encode3186934 Ref: function_encrypt3187246 Ref: function_md53188088 Ref: function_old-password3188678 Ref: function_password3189139 Ref: function_sha13190441 Ref: function_uncompress3191267 Ref: function_uncompressed-length3191774 Node: information-functions3191999 Ref: function_benchmark3193629 Ref: function_charset3196072 Ref: function_coercibility3196378 Ref: function_collation3197348 Ref: function_connection-id3197594 Ref: function_current-user3197851 Ref: function_database3200206 Ref: function_found-rows3200730 Ref: function_last-insert-id3204803 Ref: function_row-count3213141 Ref: function_schema3215316 Ref: function_session-user3215385 Ref: function_system-user3215459 Ref: function_user3215531 Ref: function_version3216064 Node: miscellaneous-functions3216632 Ref: function_default3218095 Ref: function_get-lock3218496 Ref: function_inet-aton3221457 Ref: function_inet-ntoa3222509 Ref: function_is-free-lock3222837 Ref: function_is-used-lock3223310 Ref: function_master-pos-wait3223728 Ref: function_name-const3224916 Ref: function_release-lock3225591 Ref: function_sleep3226321 Ref: function_uuid3226762 Ref: function_uuid-short3228830 Ref: function_values3229940 Node: group-by-functions-and-modifiers3230810 Node: group-by-functions3231279 Ref: function_avg3234142 Ref: function_bit-and3234508 Ref: function_bit-or3234863 Ref: function_bit-xor3235091 Ref: function_count3235321 Ref: function_count-distinct3236569 Ref: function_group-concat3237084 Ref: function_max3239601 Ref: function_min3240477 Ref: function_std3241353 Ref: function_stddev3241606 Ref: function_stddev-pop3241881 Ref: function_stddev-samp3242158 Ref: function_sum3242345 Ref: function_var-pop3242621 Ref: function_var-samp3242965 Ref: function_variance3243161 Node: group-by-modifiers3243409 Node: group-by-hidden-columns3251368 Node: spatial-extensions3255455 Node: gis-introduction3257347 Node: opengis-geometry-model3259652 Node: gis-geometry-class-hierarchy3260932 Node: gis-class-geometry3263578 Node: gis-class-point3267133 Node: gis-class-curve3267766 Node: gis-class-linestring3268613 Node: gis-class-surface3269300 Node: gis-class-polygon3270023 Node: gis-class-geometrycollection3271250 Node: gis-class-multipoint3272083 Node: gis-class-multicurve3272858 Node: gis-class-multilinestring3273820 Node: gis-class-multisurface3274259 Node: gis-class-multipolygon3274841 Node: supported-spatial-data-formats3276316 Node: gis-wkt-format3277000 Node: gis-wkb-format3279419 Node: creating-a-spatially-enabled-mysql-database3281179 Node: mysql-spatial-datatypes3281917 Node: creating-spatial-values3282905 Node: gis-wkt-functions3283583 Ref: function_geomcollfromtext3284235 Ref: function_geomfromtext3284410 Ref: function_linefromtext3284566 Ref: function_mlinefromtext3284716 Ref: function_mpointfromtext3284877 Ref: function_mpolyfromtext3285029 Ref: function_pointfromtext3285184 Ref: function_polyfromtext3285291 Ref: function_bdmpolyfromtext3285713 Ref: function_bdpolyfromtext3285909 Node: gis-wkb-functions3286094 Ref: function_geomcollfromwkb3286892 Ref: function_geomfromwkb3287065 Ref: function_linefromwkb3287219 Ref: function_mlinefromwkb3287367 Ref: function_mpointfromwkb3287526 Ref: function_mpolyfromwkb3287676 Ref: function_pointfromwkb3287829 Ref: function_polyfromwkb3287935 Ref: function_bdmpolyfromwkb3288343 Ref: function_bdpolyfromwkb3288538 Node: gis-mysql-specific-functions3288722 Ref: function_geometrycollection3290036 Ref: function_linestring3290116 Ref: function_multilinestring3290321 Ref: function_multipoint3290457 Ref: function_multipolygon3290573 Ref: function_point3290709 Ref: function_polygon3290779 Node: creating-spatial-columns3291042 Node: populating-spatial-columns3292010 Node: fetching-spatial-data3294958 Node: spatial-analysis-functions3295883 Node: functions-to-convert-geometries-between-formats3297314 Ref: function_asbinary3297720 Ref: function_astext3297907 Node: geometry-property-functions3298932 Node: general-geometry-property-functions3300022 Ref: function_dimension3300380 Ref: function_envelope3300954 Ref: function_geometrytype3301669 Ref: function_srid3302219 Ref: function_boundary3302964 Ref: function_isempty3303090 Ref: function_issimple3303300 Node: point-property-functions3303928 Ref: function_x3304257 Ref: function_y3304596 Node: linestring-property-functions3304930 Ref: function_endpoint3305335 Ref: function_glength3305805 Ref: function_numpoints3306360 Ref: function_pointn3306781 Ref: function_startpoint3307273 Ref: function_isring3307856 Node: multilinestring-property-functions3308132 Ref: function_isclosed3309073 Node: polygon-property-functions3309662 Ref: function_area3309957 Ref: function_exteriorring3310437 Ref: function_interiorringn3310999 Ref: function_numinteriorrings3311625 Node: multipolygon-property-functions3312150 Ref: function_centroid3313090 Node: geometrycollection-property-functions3313392 Ref: function_geometryn3313688 Ref: function_numgeometries3314242 Node: functions-that-create-new-geometries-from-existing-ones3314722 Node: functions-that-produce-new-geometries3315350 Node: spatial-operators3316022 Ref: function_buffer3316413 Ref: function_convexhull3316574 Ref: function_difference3316684 Ref: function_intersection3316816 Ref: function_symdifference3316953 Ref: function_union3317098 Node: functions-for-testing-spatial-relations-between-geometric-objects3317215 Node: relations-on-geometry-mbr3317936 Ref: function_mbrcontains3318536 Ref: function_mbrdisjoint3319242 Ref: function_mbrequal3319413 Ref: function_mbrintersects3319562 Ref: function_mbroverlaps3319713 Ref: function_mbrtouches3320057 Ref: function_mbrwithin3320405 Node: functions-that-test-spatial-relationships-between-geometries3321104 Ref: function_contains3321833 Ref: function_crosses3321983 Ref: function_disjoint3322610 Ref: function_equals3322736 Ref: function_intersects3322829 Ref: function_overlaps3322925 Ref: function_touches3323214 Ref: function_within3323508 Node: optimizing-spatial-analysis3323653 Node: creating-spatial-indexes3325252 Node: using-a-spatial-index3327779 Node: mysql-gis-conformance-and-compatibility3334442 Node: precision-math3335443 Node: precision-math-numbers3337912 Node: precision-math-decimal-changes3339538 Node: precision-math-expressions3343393 Node: precision-math-rounding3348175 Node: precision-math-examples3350165 Node: sql-syntax3358921 Node: sql-syntax-data-definition3359675 Node: alter-database3361845 Node: alter-event3364911 Node: alter-logfile-group3369910 Node: alter-function3373973 Node: alter-procedure3375107 Node: alter-server3376212 Node: alter-table3376984 Node: alter-table-partition-operations3401617 Node: alter-table-online-operations3412606 Ref: alter-table-online-limitations3418432 Node: alter-table-examples3424367 Node: alter-tablespace3430816 Node: alter-view3434672 Node: create-database3435654 Node: create-event3437619 Node: create-function3454069 Node: create-index3454586 Node: create-logfile-group3465542 Node: create-procedure3469811 Node: create-server3487048 Node: create-table3489776 Node: create-table-select3546760 Node: silent-column-changes3556115 Node: create-tablespace3559182 Node: create-trigger3565809 Node: create-view3575459 Node: drop-database3590894 Node: drop-event3592832 Node: drop-function3593652 Node: drop-index3594135 Node: drop-logfile-group3596190 Node: drop-procedure3597212 Node: drop-server3598274 Node: drop-table3598969 Node: drop-tablespace3600885 Node: drop-trigger3601925 Node: drop-view3603142 Node: rename-database3603979 Node: rename-table3604849 Node: truncate-table3607215 Node: sql-syntax-data-manipulation3612440 Node: call3613157 Node: delete3618625 Node: do3630351 Node: handler3630851 Node: insert3636208 Node: insert-select3650472 Node: insert-delayed3653545 Node: insert-on-duplicate3661907 Node: load-data3664743 Node: replace3695003 Node: select3698584 Node: join3722775 Node: index-hints3742244 Node: union3748809 Node: subqueries3754635 Node: scalar-subqueries3758423 Node: comparisons-using-subqueries3760752 Node: any-in-some-subqueries3762296 Node: all-subqueries3764410 Node: row-subqueries3766113 Node: exists-and-not-exists-subqueries3768653 Node: correlated-subqueries3770731 Node: from-clause-subqueries3772869 Node: subquery-errors3779318 Node: optimizing-subqueries3782113 Node: rewriting-subqueries3786216 Node: update3787840 Node: sql-syntax-transactions3794145 Node: commit3795232 Node: cannot-roll-back3802941 Node: implicit-commit3803669 Node: savepoint3809124 Node: lock-tables3811409 Node: lock-tables-and-transactions3822093 Node: lock-tables-and-triggers3825189 Node: lock-tables-restrictions3827380 Node: set-transaction3831527 Ref: isolevel_read-uncommitted3834268 Ref: isolevel_read-committed3834611 Ref: isolevel_repeatable-read3836359 Ref: isolevel_serializable3837576 Node: xa3838221 Node: xa-statements3843962 Node: xa-states3848194 Node: sql-syntax-server-administration3851172 Node: account-management-sql3851765 Node: create-user3852897 Node: drop-user3855289 Node: grant3856756 Ref: grant-privileges3859815 Ref: grant-global-privileges3864949 Ref: grant-database-privileges3865773 Ref: grant-table-privileges3866552 Ref: grant-column-privileges3867235 Ref: grant-routine-privileges3867723 Ref: grant-accounts-passwords3869894 Ref: grant-other-characteristics3874709 Ref: grant-mysql-vs-standard-sql3882913 Node: rename-user3884775 Node: revoke3886131 Node: set-password3888357 Node: table-maintenance-sql3891178 Node: analyze-table3891791 Node: backup-table3893915 Node: check-table3895400 Node: checksum-table3903471 Node: optimize-table3905091 Node: repair-table3909759 Node: restore-table3916373 Node: plugin-sql3917720 Node: create-function-udf3918218 Node: drop-function-udf3921336 Node: install-plugin3922315 Node: uninstall-plugin3927098 Node: set-option3928867 Node: show3939245 Node: show-authors3944568 Node: show-binary-logs3944962 Node: show-binlog-events3945715 Node: show-character-set3946976 Node: show-collation3948273 Node: show-columns3951115 Node: show-contributors3955837 Node: show-create-database3956321 Node: show-create-event3957445 Node: show-create-function3959499 Node: show-create-procedure3959879 Node: show-create-table3962015 Node: show-create-trigger3962886 Node: show-create-view3963942 Node: show-databases3966673 Node: show-engine3967890 Ref: show-engine-ndb-status3972367 Node: show-engines3979152 Node: show-errors3983439 Node: show-events3984170 Node: show-function-code3989773 Node: show-function-status3990132 Node: show-grants3990532 Node: show-index3992554 Node: show-innodb-status3994941 Node: show-master-status3995343 Node: show-open-tables3996091 Node: show-plugins3997770 Node: show-privileges4000392 Node: show-procedure-code4001835 Node: show-procedure-status4004239 Node: show-processlist4006126 Node: show-profile4011190 Node: show-profiles4011643 Node: show-scheduler-status4018378 Node: show-slave-hosts4020299 Node: show-slave-status4021821 Node: show-status4036318 Node: show-table-status4039504 Node: show-tables4045040 Node: show-triggers4046045 Node: show-variables4049004 Node: show-warnings4054243 Node: other-administrative-sql4059760 Node: binlog4060265 Node: cache-index4060887 Node: flush4063319 Node: kill4071552 Node: load-index4074599 Node: reset4076674 Node: sql-syntax-replication4077603 Node: replication-master-sql4078164 Node: purge-binary-logs4079155 Node: reset-master4082365 Node: set-sql-log-bin4084458 Node: replication-slave-sql4084869 Node: change-master-to4085952 Node: load-data-from-master4097691 Node: load-table-from-master4100963 Node: master-pos-wait4102749 Node: reset-slave4103246 Node: set-global-sql-slave-skip-counter4105037 Node: start-slave4106484 Node: stop-slave4110555 Node: sql-syntax-prepared-statements4111691 Node: prepare4120715 Node: execute4122257 Node: deallocate-prepare4123215 Node: statement-repreparation4123792 Node: sql-syntax-compound-statements4126014 Node: begin-end4126990 Node: declare4129065 Node: variables-in-stored-programs4129929 Node: declare-local-variable4130469 Node: set-statement4131590 Node: select-into-statement4132584 Node: local-variable-scope4133830 Node: conditions-and-handlers4136343 Node: declare-condition4136835 Node: declare-handler4137833 Node: cursors4143886 Node: declare-cursor4145592 Node: open4146374 Node: fetch4146601 Node: close4147140 Node: flow-control-constructs4147456 Node: if-statement4148662 Node: case-statement4150937 Node: loop-statement4152965 Node: leave-statement4153701 Node: iterate-statement4154157 Node: repeat-statement4154835 Node: while-statement4156023 Node: return4156750 Node: sql-syntax-utility4157275 Node: describe4157644 Node: explain4159744 Node: help4161291 Node: use4167338 Node: storage-engines4168343 Node: storage-engine-compare-transactions4182009 Node: storage-engines-other4183877 Node: storage-engine-setting4187321 Node: pluggable-storage-overview4190188 Ref: figure-storage-engine-architecture4191280 Node: pluggable-storage4192600 Node: pluggable-storage-common-layer4194382 Node: myisam-storage-engine4197725 Node: myisam-start4208020 Node: key-space4213402 Node: myisam-table-formats4214533 Node: static-format4215729 Node: dynamic-format4218134 Node: compressed-format4221350 Node: myisam-table-problems4223295 Node: corrupted-myisam-tables4223855 Node: myisam-table-close4225990 Node: innodb-storage-engine4228672 Node: innodb-contact-information4237576 Node: innodb-configuration4238284 Node: replacing-builtin-innodb4252363 Node: innodb-multiple-tablespaces4257707 Node: innodb-raw-devices4261940 Node: innodb-init4264266 Node: error-creating-innodb4267595 Node: innodb-parameters4269130 Ref: option_mysqld_ignore-builtin-innodb4279750 Ref: option_mysqld_innodb4281347 Ref: option_mysqld_innodb-status-file4281975 Ref: sysvar_ignore_builtin_innodb4282561 Ref: sysvar_innodb_adaptive_flushing4282940 Ref: sysvar_innodb_adaptive_hash_index4283992 Ref: sysvar_innodb_additional_mem_pool_size4285032 Ref: sysvar_innodb_autoextend_increment4286355 Ref: sysvar_innodb_buffer_pool_awe_mem_mb4287617 Ref: sysvar_innodb_autoinc_lock_mode4289383 Ref: sysvar_innodb_buffer_pool_size4290676 Ref: sysvar_innodb_change_buffering4293229 Ref: sysvar_innodb_checksums4294163 Ref: sysvar_innodb_commit_concurrency4295202 Ref: sysvar_innodb_concurrency_tickets4296335 Ref: sysvar_innodb_data_file_path4297800 Ref: sysvar_innodb_data_home_dir4299259 Ref: sysvar_innodb_doublewrite4300336 Ref: sysvar_innodb_fast_shutdown4301326 Ref: sysvar_innodb_file_format4302729 Ref: sysvar_innodb_file_format_check4303805 Ref: sysvar_innodb_file_io_threads4305397 Ref: sysvar_innodb_file_per_table4306537 Ref: sysvar_innodb_flush_log_at_trx_commit4307473 Ref: sysvar_innodb_flush_method4310640 Ref: sysvar_innodb_force_recovery4314925 Ref: sysvar_innodb_io_capacity4316224 Ref: sysvar_innodb_lock_wait_timeout4320071 Ref: sysvar_innodb_locks_unsafe_for_binlog4322174 Ref: sysvar_innodb_log_arch_dir4331459 Ref: sysvar_innodb_log_archive4331556 Ref: sysvar_innodb_log_buffer_size4331652 Ref: sysvar_innodb_log_file_size4332885 Ref: sysvar_innodb_log_files_in_group4334102 Ref: sysvar_innodb_log_group_home_dir4335020 Ref: sysvar_innodb_max_dirty_pages_pct4335968 Ref: sysvar_innodb_max_purge_lag4337070 Ref: sysvar_innodb_mirrored_log_groups4339357 Ref: sysvar_innodb_old_blocks_pct4339500 Ref: sysvar_innodb_old_blocks_time4340521 Ref: sysvar_innodb_open_files4342010 Ref: sysvar_innodb_read_ahead_threshold4343096 Ref: sysvar_innodb_read_io_threads4344490 Ref: sysvar_innodb_replication_delay4345444 Ref: sysvar_innodb_rollback_on_timeout4346431 Ref: sysvar_innodb_spin_wait_delay4347531 Ref: sysvar_innodb_stats_on_metadata4348481 Ref: sysvar_innodb_stats_sample_pages4350067 Ref: sysvar_innodb_strict_mode4351183 Ref: sysvar_innodb_support_xa4352346 Ref: sysvar_innodb_sync_spin_loops4354324 Ref: sysvar_innodb_table_locks4355036 Ref: sysvar_innodb_thread_concurrency4356141 Ref: sysvar_innodb_thread_sleep_delay4358092 Ref: sysvar_innodb_use_legacy_cardinality_algorithm4359016 Ref: sysvar_innodb_use_sys_malloc4360851 Ref: sysvar_innodb_version4361792 Ref: sysvar_innodb_write_io_threads4361956 Node: using-innodb-tables4364642 Node: innodb-transactions-with-different-apis4366700 Node: converting-tables-to-innodb4368830 Node: innodb-auto-increment-handling4371896 Node: innodb-auto-increment-traditional4372820 Node: innodb-auto-increment-configurable4377028 Node: innodb-foreign-key-constraints4395077 Node: innodb-and-mysql-replication4411426 Node: innodb-data-log-reconfiguration4416671 Node: innodb-backup4420601 Node: innodb-recovery4426832 Node: forcing-innodb-recovery4428221 Node: innodb-checkpoints4431429 Node: innodb-migration4433220 Node: innodb-transaction-model4434850 Node: innodb-lock-modes4438877 Node: innodb-consistent-read4443977 Node: innodb-locking-reads4448881 Node: innodb-record-level-locks4454096 Node: innodb-next-key-locking4458758 Node: innodb-locks-set4462065 Node: innodb-implicit-commit4472000 Node: innodb-deadlock-detection4472850 Node: innodb-deadlocks4474635 Node: innodb-multi-versioning4478190 Node: innodb-table-and-index4481847 Node: innodb-index-types4482888 Node: innodb-physical-structure4484728 Node: innodb-insert-buffering4486081 Node: innodb-adaptive-hash4488065 Node: innodb-physical-record4489198 Node: innodb-disk-management4494851 Node: innodb-disk-io4495268 Node: innodb-file-space4496756 Node: innodb-file-defragmenting4500348 Node: innodb-error-handling4502083 Node: innodb-error-codes4505169 Node: operating-system-error-codes4507203 Ref: operating-system-error-codes-linux4507539 Ref: operating-system-error-codes-windows4509211 Node: innodb-tuning-troubleshooting4513112 Node: innodb-tuning4513688 Node: innodb-monitors4522697 Node: innodb-standard-monitor4528595 Node: innodb-tablespace-monitor4542208 Node: innodb-table-monitor4548028 Node: innodb-troubleshooting4557407 Node: innodb-troubleshooting-datadict4559314 Node: innodb-restrictions4563867 Node: se-db24574351 Node: se-db2-installation4576029 Node: se-db2-configuration4577035 Ref: option_ibmdb2i_assume_exclusive_use4578626 Ref: option_ibmdb2i_async_enabled4579854 Ref: option_ibmdb2i_create_index_option4580871 Ref: option_ibmdb2i_compat_opt_time_as_duration4582066 Ref: option_ibmdb2i_system_trace_level4583352 Ref: ibmdb2i_compat_opt_allow_zero_date_vals4584730 Ref: ibmdb2i_propagate_default_col_vals4586422 Ref: ibmdb2i_compat_opt_year_as_int4587519 Ref: option_ibmdb2i_lob_alloc_size4588643 Ref: option_ibmdb2i_compat_opt_blob_cols4589814 Ref: option_ibmdb2i_max_read_buffer_size4591391 Ref: option_ibmdb2i_max_write_buffer_size4592505 Ref: option_ibmdb2i_rdb_name4593596 Ref: option_ibmdb2i_transaction_unsafe4594511 Node: se-db2-creating-tables4596386 Node: se-db2-creating-tables-identifiers4597556 Node: se-db2-creating-tables-indexnames4599937 Node: se-db2-data-type-mapping4601158 Node: se-db2-metadata4601778 Node: se-db2-transactions4603402 Node: se-db2-terms4608217 Node: se-db2-notes4610643 Node: se-db2-collations4615342 Node: se-db2-errors4619701 Node: merge-storage-engine4631701 Node: merge-table-advantages4638953 Node: merge-table-problems4642733 Node: memory-storage-engine4652364 Ref: memory-compared-cluster4654802 Node: example-storage-engine4665870 Node: federated-storage-engine4667222 Node: federated-description4668476 Ref: figure-se-federated-structure4670144 Node: federated-create4671420 Node: federated-create-connection4673598 Node: federated-create-server4676205 Node: federated-usagenotes4679474 Node: federated-storage-engine-resources4685049 Node: archive-storage-engine4685469 Node: csv-storage-engine4691986 Node: se-csv-repair4694148 Node: se-csv-limitations4697179 Node: blackhole-storage-engine4697815 Node: ha-overview4704145 Ref: figure_ha-cost-vs-nines4707150 Ref: figure_ha-application-architecture-mapping4707452 Ref: ha-availability-comparison4707630 Node: ha-ovm-template4711971 Node: ha-drbd4714482 Ref: ha-drbd-overview4716036 Node: ha-drbd-install4717062 Node: ha-drbd-install-os4721116 Node: ha-drbd-install-drbd4728444 Node: ha-drbd-install-drbd-primary4731431 Node: ha-drbd-install-drbd-secondary4736723 Node: ha-drbd-install-drbd-using4738822 Node: ha-drbd-install-drbd-management4741199 Node: ha-drbd-install-drbd-othercfg4742992 Node: ha-drbd-install-mysql4744828 Node: ha-drbd-performance4747341 Ref: ha-drbd-performance-sepinterface4748286 Node: ha-drbd-performance-bonded4748878 Node: ha-drbd-performance-syncrate4754769 Node: ha-heartbeat4758353 Ref: ha-heartbeat-overview4760468 Node: ha-heartbeat-config4761688 Node: ha-heartbeat-drbd4766191 Node: ha-heartbeat-drbd-dopd4770713 Node: ha-heartbeat-errors4773351 Node: ha-vm4774658 Node: ha-vm-aws-setup4778059 Node: ha-vm-aws-instance4782010 Node: ha-vm-aws-deploy4783994 Node: ha-zfs-replication4788170 Node: ha-zfs-config4793028 Node: ha-zfs-mysql4796399 Node: ha-zfs-mysql-recovery4798074 Node: ha-memcached4799877 Ref: ha-memcached-fig-overview4801962 Node: ha-memcached-install4804176 Node: ha-memcached-using4807332 Node: ha-memcached-using-deployment4817595 Node: ha-memcached-using-namespaces4819919 Node: ha-memcached-using-expiry4821353 Node: ha-memcached-using-hashtypes4823606 Ref: ha-memcached-using-hashtypes-fig-selection4825586 Ref: ha-memcached-using-hashtypes-fig-addselect4828770 Node: ha-memcached-using-dtrace4832004 Node: ha-memcached-using-memory4840128 Ref: ha-memcached-fig-slabs4842367 Node: ha-memcached-using-threads4844256 Node: ha-memcached-using-logs4846070 Node: ha-memcached-interfaces4855300 Ref: ha-memcached-fig-basicflow4857219 Node: ha-memcached-interfaces-libmemcached4860194 Node: ha-memcached-interfaces-libmemcached-base4864293 Node: ha-memcached-interfaces-libmemcached-servers4865465 Node: ha-memcached-interfaces-libmemcached-set4868804 Node: ha-memcached-interfaces-libmemcached-get4873884 Node: ha-memcached-interfaces-libmemcached-behaviors4878500 Node: ha-memcached-interfaces-libmemcached-utilities4882542 Node: ha-memcached-interfaces-perl4884389 Node: ha-memcached-interfaces-python4891116 Node: ha-memcached-interfaces-php4897257 Node: ha-memcached-interfaces-ruby4904587 Node: ha-memcached-interfaces-java4907380 Node: ha-memcached-interfaces-mysqludf4911179 Node: ha-memcached-interfaces-protocol4918086 Node: ha-memcached-interfaces-protocol-tcp4918563 Ref: ha-memcached-interfaces-protocol-responses4927846 Node: ha-memcached-stats4929348 Node: ha-memcached-stats-general4935207 Node: ha-memcached-stats-slabs4941254 Node: ha-memcached-stats-items4945454 Node: ha-memcached-stats-sizes4947977 Node: ha-memcached-stats-detail4949302 Node: ha-memcached-stats-memcached-tool4951505 Node: ha-memcached-faq4957374 Ref: qandaitem-15-6-5-1-14961544 Ref: qandaitem-15-6-5-1-24961881 Ref: qandaitem-15-6-5-1-34962108 Ref: qandaitem-15-6-5-1-44962303 Ref: qandaitem-15-6-5-1-54962942 Ref: qandaitem-15-6-5-1-64963212 Ref: qandaitem-15-6-5-1-74963922 Ref: qandaitem-15-6-5-1-84964728 Ref: qandaitem-15-6-5-1-94965396 Ref: qandaitem-15-6-5-1-104965674 Ref: qandaitem-15-6-5-1-114966419 Ref: qandaitem-15-6-5-1-124966734 Ref: qandaitem-15-6-5-1-134967111 Ref: qandaitem-15-6-5-1-144967447 Ref: qandaitem-15-6-5-1-154967808 Ref: qandaitem-15-6-5-1-164968799 Ref: qandaitem-15-6-5-1-174969372 Ref: qandaitem-15-6-5-1-184969861 Ref: qandaitem-15-6-5-1-194970439 Ref: qandaitem-15-6-5-1-204970501 Ref: qandaitem-15-6-5-1-214971108 Ref: qandaitem-15-6-5-1-224971858 Ref: qandaitem-15-6-5-1-234972098 Ref: qandaitem-15-6-5-1-244972666 Ref: qandaitem-15-6-5-1-254973665 Ref: qandaitem-15-6-5-1-264974216 Ref: qandaitem-15-6-5-1-274974915 Ref: qandaitem-15-6-5-1-284975144 Ref: qandaitem-15-6-5-1-294976728 Ref: qandaitem-15-6-5-1-304977060 Node: mysql-proxy4978702 Node: mysql-proxy-platforms4981289 Node: mysql-proxy-install4982329 Node: mysql-proxy-install-binary4983439 Node: mysql-proxy-install-source4984917 Node: mysql-proxy-install-cvs4986515 Node: mysql-proxy-configuration-windows4988394 Node: mysql-proxy-configuration4990534 Ref: option_mysql-proxy_help4997515 Ref: option_mysql-proxy_help-admin4997768 Ref: option_mysql-proxy_help-all4998000 Ref: option_mysql-proxy_help-proxy4998212 Ref: option_mysql-proxy_admin-address4998444 Ref: option_mysql-proxy_admin-lua-script4999006 Ref: option_mysql-proxy_admin-password4999572 Ref: option_mysql-proxy_admin-username5000231 Ref: option_mysql-proxy_basedir5000932 Ref: option_mysql-proxy_daemon5001631 Ref: option_mysql-proxy_defaults-file5001845 Ref: option_mysql-proxy_event-threads5002145 Ref: option_mysql-proxy_keepalive5002658 Ref: option_mysql-proxy_log-backtrace-on-crash5003243 Ref: option_mysql-proxy_log-file5003588 Ref: option_mysql-proxy_log-level5004175 Ref: option_mysql-proxy_log-use-syslog5004987 Ref: option_mysql-proxy_lua-cpath5005244 Ref: option_mysql-proxy_lua-path5005771 Ref: option_mysql-proxy_max-open-files5006259 Ref: option_mysql-proxy_no-proxy5006832 Ref: option_mysql-proxy_plugin-dir5007047 Ref: option_mysql-proxy_plugins5007575 Ref: option_mysql-proxy_proxy-address5008010 Ref: option_mysql-proxy_proxy-read-only-backend-addresses5008692 Ref: option_mysql-proxy_proxy-backend-addresses5010381 Ref: option_mysql-proxy_proxy-pool-no-change-user5011946 Ref: option_mysql-proxy_proxy-skip-profiling5012373 Ref: option_mysql-proxy_proxy-fix-bug-253715012710 Ref: option_mysql-proxy_proxy-lua-script5013410 Ref: option_mysql-proxy_pid-file5014371 Ref: option_mysql-proxy_user5014862 Ref: option_mysql-proxy_version5015302 Node: mysql-proxy-scripting5016887 Node: mysql-proxy-scripting-injection5021726 Node: mysql-proxy-scripting-structures5024571 Ref: mysql-proxy-scripting-structures-proxy5025224 Ref: mysql-proxy-scripting-structures-connection5026281 Ref: mysql-proxy-scripting-structures-backends5028558 Ref: mysql-proxy-scripting-structures-queries5029856 Ref: mysql-proxy-scripting-structures-response5032494 Ref: mysql-proxy-scripting-structures-resultset5035444 Ref: mysql-proxy-scripting-structures-return-states5037393 Ref: mysql-proxy-scripting-structures-packet-states5038216 Ref: mysql-proxy-scripting-structures-backend-states5038550 Ref: mysql-proxy-scripting-structures-command-constants5039164 Ref: mysql-proxy-scripting-structures-type-constants5040769 Node: mysql-proxy-scripting-connect-server5042003 Node: mysql-proxy-scripting-read-handshake5043505 Node: mysql-proxy-scripting-read-auth5045649 Node: mysql-proxy-scripting-read-auth-result5047091 Node: mysql-proxy-scripting-read-query5048727 Node: mysql-proxy-scripting-read-query-result5052147 Node: mysql-proxy-using5056854 Node: mysql-proxy-using-admin5059313 Node: mysql-proxy-faq5071998 Ref: qandaitem-15-7-6-1-15076832 Ref: qandaitem-15-7-6-1-25077271 Ref: qandaitem-15-7-6-1-35077482 Ref: qandaitem-15-7-6-1-45077669 Ref: qandaitem-15-7-6-1-55077949 Ref: qandaitem-15-7-6-1-65078284 Ref: qandaitem-15-7-6-1-75078533 Ref: qandaitem-15-7-6-1-85078773 Ref: qandaitem-15-7-6-1-95079089 Ref: qandaitem-15-7-6-1-105079263 Ref: qandaitem-15-7-6-1-115079493 Ref: qandaitem-15-7-6-1-125079610 Ref: qandaitem-15-7-6-1-135079860 Ref: qandaitem-15-7-6-1-145080178 Ref: qandaitem-15-7-6-1-155080378 Ref: qandaitem-15-7-6-1-165080653 Ref: qandaitem-15-7-6-1-175080877 Ref: qandaitem-15-7-6-1-185081124 Ref: qandaitem-15-7-6-1-195081344 Ref: qandaitem-15-7-6-1-205081575 Ref: qandaitem-15-7-6-1-215081780 Ref: qandaitem-15-7-6-1-225081957 Ref: qandaitem-15-7-6-1-235082150 Ref: qandaitem-15-7-6-1-245082495 Ref: qandaitem-15-7-6-1-255082668 Ref: qandaitem-15-7-6-1-265083035 Ref: qandaitem-15-7-6-1-275083369 Ref: qandaitem-15-7-6-1-285083614 Ref: qandaitem-15-7-6-1-295083919 Ref: qandaitem-15-7-6-1-305084181 Ref: qandaitem-15-7-6-1-315084363 Ref: qandaitem-15-7-6-1-325084646 Ref: qandaitem-15-7-6-1-335084771 Ref: qandaitem-15-7-6-1-345085081 Ref: qandaitem-15-7-6-1-355085306 Ref: qandaitem-15-7-6-1-365085597 Ref: qandaitem-15-7-6-1-375085812 Node: replication5086108 Node: replication-configuration5090288 Node: replication-howto5094087 Node: replication-howto-masterbaseconfig5098438 Node: replication-howto-slavebaseconfig5100487 Node: replication-howto-repuser5102022 Node: replication-howto-masterstatus5103749 Node: replication-howto-mysqldump5107555 Node: replication-howto-rawdata5109863 Node: replication-howto-newservers5113631 Node: replication-howto-existingdata5115541 Node: replication-howto-additionalslaves5120153 Node: replication-howto-slaveinit5124111 Node: replication-formats5125329 Node: replication-sbr-rbr5129514 Node: replication-rbr-usage5139120 Node: replication-rbr-safe-unsafe5145447 Ref: replication-rbr-safe-unsafe-not5147631 Node: replication-options5150090 Ref: option_mysqld_server-id5151152 Node: replication-options-table5152550 Node: replication-options-master5161647 Ref: sysvar_auto_increment_increment5162639 Ref: sysvar_auto_increment_offset5171020 Node: replication-options-slave5172247 Ref: replication-optvars-slaves5177140 Ref: option_mysqld_abort-slave-event-count5177569 Ref: option_mysqld_disconnect-slave-event-count5178858 Ref: option_mysqld_log-slave-updates5179446 Ref: option_mysqld_log-slow-slave-statements5181863 Ref: option_mysqld_master-connect-retry5184151 Ref: option_mysqld_master-host5185297 Ref: option_mysqld_master-info-file5186059 Ref: option_mysqld_master-password5186811 Ref: option_mysqld_master-port5187622 Ref: option_mysqld_master-retry-count5188428 Ref: option_mysqld_master-ssl5189807 Ref: option_mysqld_master-user5190482 Ref: option_mysqld_max-relay-log-size5191407 Ref: option_mysqld_read-only5191597 Ref: option_mysqld_relay-log5191932 Ref: option_mysqld_relay-log-index5193981 Ref: option_mysqld_relay-log-info-file5195707 Ref: option_mysqld_relay-log-purge5196570 Ref: option_mysqld_relay-log-space-limit5196844 Ref: option_mysqld_replicate-do-db5198061 Ref: option_mysqld_replicate-ignore-db5203223 Ref: option_mysqld_replicate-do-table5206226 Ref: option_mysqld_replicate-ignore-table5207251 Ref: option_mysqld_replicate-rewrite-db5208358 Ref: option_mysqld_replicate-same-server-id5209745 Ref: option_mysqld_replicate-wild-do-table5210926 Ref: option_mysqld_replicate-wild-ignore-table5213347 Ref: option_mysqld_report-host5214547 Ref: option_mysqld_report-password5215753 Ref: option_mysqld_report-port5216919 Ref: option_mysqld_report-user5217893 Ref: option_mysqld_show-slave-auth-info5219018 Ref: option_mysqld_skip-slave-start5219686 Ref: optvar_slave_compressed_protocol5220292 Ref: option_mysqld_slave-load-tmpdir5221190 Ref: option_mysqld_slave-net-timeout5222417 Ref: option_mysqld_slave-skip-errors5223704 Ref: replication-sysvars-slaves5225797 Ref: sysvar_init_slave5226125 Ref: sysvar_relay_log_index5227227 Ref: sysvar_relay_log_info_file5228081 Ref: sysvar_rpl_recovery_rank5228940 Ref: sysvar_slave_compressed_protocol5229027 Ref: sysvar_slave_exec_mode5229859 Ref: sysvar_slave_load_tmpdir5231260 Ref: sysvar_slave_net_timeout5232121 Ref: sysvar_slave_skip_errors5233089 Ref: sysvar_slave_transaction_retries5233857 Ref: sysvar_slave_type_conversions5235512 Ref: sysvar_sql_slave_skip_counter5237195 Node: replication-options-binary-log5238020 Ref: replication-optvars-binlog5238662 Ref: option_mysqld_binlog-row-event-max-size5238879 Ref: option_mysqld_log-bin5240101 Ref: option_mysqld_log-bin-index5241360 Ref: option_mysqld_log-bin-trust-function-creators5242049 Ref: option_mysqld_binlog-do-db5243625 Ref: option_mysqld_binlog-ignore-db5249377 Ref: option_mysqld_max-binlog-dump-events5252559 Ref: option_mysqld_sporadic-binlog-dump-fail5253125 Ref: replication-sysvars-binlog5253694 Ref: sysvar_binlog_cache_size5254012 Ref: sysvar_binlog_direct_non_transactional_updates5255674 Ref: sysvar_binlog_format5258436 Ref: sysvar_max_binlog_cache_size5263172 Ref: sysvar_max_binlog_size5264846 Ref: sysvar_sync_binlog5266176 Node: replication-administration5268038 Node: replication-administration-status5268648 Node: replication-administration-pausing5275216 Node: replication-implementation5277306 Node: replication-implementation-details5279963 Node: slave-logs5285629 Node: slave-logs-relaylog5286869 Node: slave-logs-status5290267 Node: replication-rules5295763 Node: replication-rules-db-options5298905 Node: replication-rules-table-options5302591 Node: replication-rules-examples5305887 Node: replication-solutions5309069 Node: replication-solutions-backups5311302 Node: replication-solutions-backups-mysqldump5313336 Node: replication-solutions-backups-rawdata5316043 Node: replication-solutions-backups-read-only5318898 Node: replication-solutions-diffengines5323300 Node: replication-solutions-scaleout5327415 Ref: figure_replication-scaleout5328608 Node: replication-solutions-partitioning5330593 Ref: figure_replication-multi-db5331209 Node: replication-solutions-performance5333438 Ref: figure_replication-performance5334583 Node: replication-solutions-switch5336839 Ref: figure_replication-redundancy-before5338448 Ref: figure_replication-redundancy-after5341615 Node: replication-solutions-ssl5342957 Node: replication-notes5347079 Node: replication-features5347645 Node: replication-features-auto-increment5352366 Node: replication-features-charset5355623 Node: replication-features-create-if-not-exists5357875 Node: replication-features-create-select5359503 Node: replication-features-current-user5361862 Node: replication-features-drop-if-exists5363694 Node: replication-features-differing-tables5364629 Node: replication-features-more-columns5365893 Node: replication-features-different-data-types5370745 Ref: replication-features-attribute-promotion5376546 Node: replication-features-directory5383287 Node: replication-features-invoked5384282 Node: replication-features-floatvalues5389597 Node: replication-features-flush5390473 Node: replication-features-functions5391915 Node: replication-features-limit5399413 Node: replication-features-load-data5400521 Node: replication-features-logging5401513 Node: replication-features-repair-table5401957 Node: replication-features-shutdowns5402920 Node: replication-features-max-allowed-packet5405407 Node: replication-features-memory5406888 Node: replication-features-temptables5409201 Node: replication-features-mysqldb5411505 Node: replication-features-optimizer5412627 Node: replication-features-reserved-words5413389 Node: replication-features-set-password5415496 Node: replication-features-slaveerrors5416008 Node: replication-features-sql-mode5418355 Node: replication-features-timeout5419431 Node: replication-features-timestamp5420306 Node: replication-features-timezone5421239 Node: replication-features-transactions5422282 Node: replication-features-triggers5428207 Node: replication-features-views5430062 Node: replication-features-truncate5430692 Node: replication-features-variables5431892 Node: replication-compatibility5435638 Node: replication-upgrade5439704 Node: replication-faq5443672 Ref: qandaitem-16-4-4-1-15445453 Ref: qandaitem-16-4-4-1-25446293 Ref: qandaitem-16-4-4-1-35446644 Ref: qandaitem-16-4-4-1-45447811 Ref: qandaitem-16-4-4-1-55448814 Ref: qandaitem-16-4-4-1-65450200 Ref: qandaitem-16-4-4-1-75450788 Ref: qandaitem-16-4-4-1-85451012 Ref: qandaitem-16-4-4-1-95454051 Ref: qandaitem-16-4-4-1-105454777 Ref: qandaitem-16-4-4-1-115455280 Ref: qandaitem-16-4-4-1-125455399 Ref: qandaitem-16-4-4-1-135455664 Ref: qandaitem-16-4-4-1-145455820 Node: replication-problems5455987 Node: replication-bugs5461153 Node: mysql-cluster5463828 Node: mysql-cluster-overview5474841 Node: mysql-cluster-basics5479846 Node: mysql-cluster-nodes-groups5490750 Ref: mysql-cluster-nodes-groups-nodegroup5492003 Ref: mysql-cluster-nodes-groups-partition5493241 Ref: mysql-cluster-nodes-groups-user-partitioning5493628 Ref: mysql-cluster-nodes-groups-replica5495121 Node: mysql-cluster-overview-requirements5497765 Ref: mysql-cluster-network-latency-issues5500947 Node: mysql-cluster-development5504326 Node: mysql-cluster-development-5-1-ndb-7-25508392 Node: mysql-cluster-development-5-1-ndb-7-15512916 Node: mysql-cluster-development-5-1-ndb-7-05534990 Node: mysql-cluster-development-5-1-ndb-6-35564275 Node: mysql-cluster-development-5-1-ndb-6-25586896 Node: mysql-cluster-development-5-1-ndb-6-15596360 Node: mysql-cluster-development-5-15598262 Ref: mysql-cluster-development-5-1-distribution-awareness5602437 Node: mysql-cluster-compared5604208 Node: mysql-cluster-ndb-innodb-engines5608012 Node: mysql-cluster-ndb-innodb-workloads5616106 Node: mysql-cluster-ndb-innodb-usage5617989 Node: mysql-cluster-limitations5619895 Node: mysql-cluster-limitations-syntax5622388 Node: mysql-cluster-limitations-limits5629631 Node: mysql-cluster-limitations-transactions5634070 Node: mysql-cluster-limitations-error-handling5641737 Node: mysql-cluster-limitations-database-objects5642794 Node: mysql-cluster-limitations-unsupported5645259 Node: mysql-cluster-limitations-performance5647334 Node: mysql-cluster-limitations-exclusive-to-cluster5648541 Node: mysql-cluster-limitations-disk-data5650804 Node: mysql-cluster-limitations-multiple-nodes5652173 Node: mysql-cluster-limitations-resolved5654357 Node: mysql-cluster-installation5670311 Node: mysql-cluster-install-linux5676938 Node: mysql-cluster-install-linux-binary5679191 Node: mysql-cluster-install-linux-rpm5685171 Node: mysql-cluster-install-linux-source5691911 Node: mysql-cluster-install-windows5697333 Node: mysql-cluster-install-windows-binary5698656 Node: mysql-cluster-install-windows-source5711927 Node: mysql-cluster-install-windows-initial-start5714820 Node: mysql-cluster-install-windows-service5723761 Node: mysql-cluster-install-configuration5731207 Node: mysql-cluster-install-first-start5736945 Node: mysql-cluster-install-example-data5739875 Node: mysql-cluster-install-shutdown-restart5749590 Node: mysql-cluster-upgrade-downgrade5752556 Node: mysql-cluster-upgrade-downgrade-compatibility-7.x5755242 Node: mysql-cluster-upgrade-downgrade-compatibility-6.x5763278 Ref: mysql-cluster-upgrade-downgrade-compatibility-online-add-drop-column-6-x5765581 Node: mysql-cluster-upgrade-downgrade-compatibility-5.15768023 Ref: mysql-cluster-upgrade-downgrade-compatibility-online-add-drop-column5772590 Node: mysql-cluster-configuration5774667 Node: mysql-cluster-quick5776842 Node: mysql-cluster-config-file5782410 Node: mysql-cluster-config-example5788189 Ref: mysql-cluster-config-ini-sections5794353 Node: mysql-cluster-config-starting5796700 Node: mysql-cluster-connectstring5810341 Node: mysql-cluster-computer-definition5815302 Ref: ndbparam-computer-id5815763 Ref: ndbparam-computer-hostname5816522 Node: mysql-cluster-mgm-definition5816928 Ref: ndbparam-mgmd-id5817602 Ref: ndbparam-mgmd-nodeid5819109 Ref: ndbparam-mgmd-executeoncomputer5820538 Ref: ndbparam-mgmd-portnumber5821034 Ref: ndbparam-mgmd-hostname5821519 Ref: ndbparam-mgmd-logdestination5822104 Ref: ndbparam-mgmd-arbitrationrank5824243 Ref: ndbparam-mgmd-arbitrationdelay5825840 Ref: ndbparam-mgmd-datadir5826438 Ref: ndbparam-mgmd-heartbeatthreadpriority5827293 Ref: ndbparam-mgmd-totalsendbuffermemory5827940 Node: mysql-cluster-ndbd-definition5829013 Ref: mysql-cluster-identifying-data-nodes5831566 Ref: ndbparam-ndbd-id5831727 Ref: ndbparam-ndbd-nodeid5832751 Ref: ndbparam-ndbd-executeoncomputer5833681 Ref: ndbparam-ndbd-hostname5834152 Ref: ndbparam-ndbd-serverport5834734 Ref: ndbparam-ndbd-tcpbind_inaddr_any5836227 Ref: ndbparam-ndbd-nodegroup5836499 Ref: ndbparam-ndbd-noofreplicas5838031 Ref: ndbparam-ndbd-datadir5841430 Ref: ndbparam-ndbd-filesystempath5842004 Ref: ndbparam-ndbd-backupdatadir5843118 Ref: mysql-cluster-data-memory-index-memory-string-memory5844018 Ref: ndbparam-ndbd-datamemory5844399 Ref: ndbparam-ndbd-indexmemory5849986 Ref: ndbparam-ndbd-stringmemory5851018 Ref: mysql-cluster-transaction-parameters5855785 Ref: ndbparam-ndbd-maxnoofconcurrenttransactions5856635 Ref: ndbparam-ndbd-maxnoofconcurrentoperations5858596 Ref: ndbparam-ndbd-maxnooflocaloperations5861568 Ref: ndbparam-ndbd-maxdmloperationspertransaction5862334 Ref: mysql-cluster-transaction-temporary-storage5863605 Ref: ndbparam-ndbd-maxnoofconcurrentindexoperations5864225 Ref: ndbparam-ndbd-maxnooffiredtriggers5865484 Ref: ndbparam-ndbd-transactionbuffermemory5866738 Ref: mysql-cluster-scans-and-buffering5867977 Ref: ndbparam-ndbd-maxnoofconcurrentscans5868470 Ref: ndbparam-ndbd-maxnooflocalscans5870067 Ref: ndbparam-ndbd-batchsizeperlocalscan5870899 Ref: ndbparam-ndbd-longmessagebuffer5871513 Ref: ndbparam-ndbd-maxparallelscansperfragment5873052 Ref: mysql-cluster-memory-allocation5874661 Ref: ndbparam-ndbd-maxallocate5874684 Ref: mysql-cluster-logging-and-checkpointing5875328 Ref: ndbparam-ndbd-nooffragmentlogfiles5875432 Ref: ndbparam-ndbd-fragmentlogfilesize5878136 Ref: ndbparam-ndbd-initfragmentlogfiles5879305 Ref: ndbparam-ndbd-maxnoofopenfiles5880638 Ref: ndbparam-ndbd-initialnoofopenfiles5881695 Ref: ndbparam-ndbd-maxnoofsavedmessages5882289 Ref: ndbparam-ndbd-maxlcpstartdelay5882889 Ref: mysql-cluster-metadata-objects5885072 Ref: ndbparam-ndbd-maxnoofattributes5885428 Ref: ndbparam-ndbd-maxnooftables5888030 Ref: ndbparam-ndbd-maxnooforderedindexes5889703 Ref: ndbparam-ndbd-maxnoofuniquehashindexes5890766 Ref: ndbparam-ndbd-maxnooftriggers5891716 Ref: ndbparam-ndbd-maxnoofindexes5892604 Ref: ndbparam-ndbd-maxnoofsubscriptions5892995 Ref: ndbparam-ndbd-maxnoofsubscribers5894247 Ref: ndbparam-ndbd-maxnoofconcurrentsuboperations5896103 Ref: mysql-cluster-boolean-parameters5897332 Ref: ndbparam-ndbd-lockpagesinmainmemory5897579 Ref: ndbparam-ndbd-stoponerror5900234 Ref: ndbparam-ndbd-diskless5900825 Ref: ndbparam-ndbd-odirect5901961 Ref: ndbparam-ndbd-restartonerrorinsert5903444 Ref: ndbparam-ndbd-compressedbackup5904050 Ref: ndbparam-ndbd-compressedlcp5905147 Ref: mysql-cluster-timeouts-intervals-disk-paging5906254 Ref: ndbparam-ndbd-timebetweenwatchdogcheck5906550 Ref: ndbparam-ndbd-timebetweenwatchdogcheckinitial5907529 Ref: ndbparam-ndbd-startpartialtimeout5908400 Ref: ndbparam-ndbd-startpartitionedtimeout5909280 Ref: ndbparam-ndbd-startfailuretimeout5910121 Ref: ndbparam-ndbd-startnonodegrouptimeout5911123 Ref: ndbparam-ndbd-heartbeatintervaldbdb5912489 Ref: ndbparam-ndbd-heartbeatintervaldbapi5913870 Ref: ndbparam-ndbd-heartbeatorder5915099 Ref: ndbparam-ndbd-timebetweenlocalcheckpoints5919918 Ref: ndbparam-ndbd-timebetweenglobalcheckpoints5921397 Ref: ndbparam-ndbd-timebetweenepochs5922928 Ref: ndbparam-ndbd-timebetweenepochstimeout5924069 Ref: ndbparam-ndbd-maxbufferedepochs5927489 Ref: ndbparam-ndbd-timebetweeninactivetransactionabortcheck5928852 Ref: ndbparam-ndbd-transactioninactivetimeout5929592 Ref: ndbparam-ndbd-transactiondeadlockdetectiontimeout5930399 Ref: ndbparam-ndbd-disksyncsize5932111 Ref: ndbparam-ndbd-diskcheckpointspeed5933048 Ref: ndbparam-ndbd-diskcheckpointspeedinrestart5933955 Ref: ndbparam-ndbd-noofdiskpagestodiskafterrestarttup5934631 Ref: ndbparam-ndbd-noofdiskpagestodiskafterrestartacc5936584 Ref: ndbparam-ndbd-noofdiskpagestodiskduringrestarttup5937514 Ref: ndbparam-ndbd-noofdiskpagestodiskduringrestartacc5938786 Ref: ndbparam-ndbd-arbitrationtimeout5939858 Ref: ndbparam-ndbd-arbitration5940580 Ref: mysql-cluster-buffering-and-logging5942886 Ref: ndbparam-ndbd-undoindexbuffer5943394 Ref: ndbparam-ndbd-undodatabuffer5945480 Ref: ndbparam-ndbd-redobuffer5947107 Ref: mysql-cluster-controlling-log-messages5948387 Ref: ndbparam-ndbd-loglevelstartup5949172 Ref: ndbparam-ndbd-loglevelshutdown5949654 Ref: ndbparam-ndbd-loglevelstatistic5950147 Ref: ndbparam-ndbd-loglevelcheckpoint5950733 Ref: ndbparam-ndbd-loglevelnoderestart5951266 Ref: ndbparam-ndbd-loglevelconnection5951741 Ref: ndbparam-ndbd-loglevelerror5952236 Ref: ndbparam-ndbd-loglevelcongestion5952823 Ref: ndbparam-ndbd-loglevelinfo5953382 Ref: ndbparam-ndbd-memreportfrequency5953883 Ref: ndbparam-ndbd-startupstatusreportfrequency5955760 Ref: ndbparam-ndbd-dicttrace5957622 Ref: mysql-cluster-backup-parameters5958043 Ref: ndbparam-ndbd-backupdatabuffersize5958183 Ref: ndbparam-ndbd-backuplogbuffersize5959263 Ref: ndbparam-ndbd-backupmemory5960948 Ref: ndbparam-ndbd-backupreportfrequency5961796 Ref: ndbparam-ndbd-backupwritesize5962727 Ref: ndbparam-ndbd-backupmaxwritesize5963372 Ref: mysql-cluster-realtime-performance-parameters5964316 Ref: ndbparam-ndbd-lockexecutethreadtocpu5964663 Ref: ndbparam-ndbd-lockmaintthreadstocpu5966336 Ref: ndbparam-ndbd-realtimescheduler5967203 Ref: ndbparam-ndbd-schedulerexecutiontimer5967788 Ref: ndbparam-ndbd-schedulerspintimer5968716 Ref: ndbparam-ndbd-buildindexthreads5969294 Ref: ndbparam-ndbd-twopassinitialnoderestartcopy5971048 Ref: ndbparam-ndbd-numa5971419 Ref: mysql-cluster-ndbd-definition-disk-data-parameters5972453 Ref: ndbparam-ndbd-diskpagebuffermemory5972572 Ref: ndbparam-ndbd-sharedglobalmemory5973803 Ref: ndbparam-ndbd-diskiothreadpool5975241 Ref: mysql-cluster-ndbd-disk-data-filesystem-parameters5978082 Ref: ndbparam-ndbd-filesystempathdd5978368 Ref: ndbparam-ndbd-filesystempathdatafiles5980291 Ref: ndbparam-ndbd-filesystempathundofiles5981961 Ref: mysql-cluster-ndbd-disk-data-object-creation-parameters5983722 Ref: ndbparam-ndbd-initiallogfilegroup5983975 Ref: ndbparam-ndbd-initialtablespace5987190 Ref: mysql-cluster-ndbd-definition-gcp-stop-errors5990028 Ref: ndbparam-ndbd-totalsendbuffermemory5993523 Ref: ndbparam-ndbd-reservedsendbuffermemory5993887 Ref: mysql-cluster-redo-over-commit-handling5994804 Ref: ndbparam-ndbd-redoovercommitcounter5995603 Ref: ndbparam-ndbd-redoovercommitlimit5996629 Ref: ndbparam-ndbd-startfailretrydelay5998531 Ref: ndbparam-ndbd-maxstartfailretries6000281 Node: mysql-cluster-api-definition6002015 Ref: ndbparam-api-id6003242 Ref: ndbparam-api-nodeid6004715 Ref: ndbparam-api-executeoncomputer6006098 Ref: ndbparam-api-hostname6006602 Ref: ndbparam-api-arbitrationrank6007608 Ref: ndbparam-api-arbitrationdelay6008936 Ref: ndbparam-api-batchbytesize6009557 Ref: ndbparam-api-batchsize6010640 Ref: ndbparam-api-heartbeatthreadpriority6011109 Ref: ndbparam-api-maxscanbatchsize6011740 Ref: ndbparam-api-totalsendbuffermemory6012480 Ref: ndbparam-api-autoreconnect6013474 Ref: ndbparam-api-defaultoperationredoproblemaction6014829 Node: mysql-cluster-tcp-definition6017438 Ref: ndbparam-tcp-nodeid16018975 Ref: ndbparam-tcp-nodeid26019321 Ref: ndbparam-tcp-hostname16019968 Ref: ndbparam-tcp-hostname26020317 Ref: ndbparam-tcp-overloadlimit6020919 Ref: ndbparam-tcp-sendbuffermemory6021517 Ref: ndbparam-tcp-sendsignalid6023173 Ref: ndbparam-tcp-checksum6023957 Ref: ndbparam-tcp-portnumber6024704 Ref: ndbparam-tcp-receivebuffermemory6024979 Node: mysql-cluster-tcp-definition-direct6025679 Node: mysql-cluster-shm-definition6027570 Ref: ndbparam-shm-nodeid16028716 Ref: ndbparam-shm-nodeid26029063 Ref: ndbparam-shm-hostname16029568 Ref: ndbparam-shm-hostname26029917 Ref: ndbparam-shm-shmkey6030519 Ref: ndbparam-shm-shmsize6031073 Ref: ndbparam-shm-sendsignalid6031648 Ref: ndbparam-shm-checksum6032338 Ref: ndbparam-shm-signum6033063 Node: mysql-cluster-sci-definition6034071 Ref: ndbparam-sci-nodeid16035470 Ref: ndbparam-sci-nodeid26035817 Ref: ndbparam-sci-host1sciid06036322 Ref: ndbparam-sci-host1sciid16036778 Ref: ndbparam-sci-host2sciid06037377 Ref: ndbparam-sci-host2sciid16037834 Ref: ndbparam-sci-hostname16038328 Ref: ndbparam-sci-hostname26038677 Ref: ndbparam-sci-sharedbuffersize6039279 Ref: ndbparam-sci-sendlimit6040093 Ref: ndbparam-sci-sendsignalid6040779 Ref: ndbparam-sci-checksum6041415 Node: mysql-cluster-config-lcp-params6042130 Node: mysql-cluster-config-send-buffers6048754 Node: mysql-cluster-params-overview6052581 Node: mysql-cluster-params-ndbd6056004 Node: mysql-cluster-params-mgmd6067458 Node: mysql-cluster-params-api6070430 Node: mysql-cluster-params-other6073760 Node: mysql-cluster-options-variables6078774 Node: mysql-cluster-option-tables6079792 Node: mysql-cluster-program-options-mysqld6086007 Ref: option_mysqld_ndb-batch-size6087203 Ref: option_mysqld_ndb-cluster-connection-pool6087946 Ref: option_mysqld_ndb-blob-read-batch-bytes6090837 Ref: option_mysqld_ndb-blob-write-batch-bytes6092701 Ref: option_mysqld_ndb-connectstring6094585 Ref: option_mysqld_ndbcluster6095223 Ref: option_mysqld_ndb-log-apply-status6096151 Ref: option_mysqld_ndb-nodeid6098115 Ref: option_mysqld_server-id-bits6100417 Ref: option_mysqld_skip-ndbcluster6102643 Ref: option_mysqld_ndb-wait-connected6103237 Ref: option_mysqld_ndb-wait-setup6104192 Node: mysql-cluster-system-variables6105261 Ref: sysvar_have_ndbcluster6105872 Ref: sysvar_multi_range_count6106502 Ref: sysvar_ndb_autoincrement_prefetch_sz6107901 Ref: sysvar_ndb_cache_check_time6110019 Ref: sysvar_ndb_extra_logging6111288 Ref: sysvar_ndb_force_send6112870 Ref: sysvar_ndb_index_stat_cache_entries6113701 Ref: sysvar_ndb_index_stat_enable6114646 Ref: sysvar_ndb_index_stat_update_freq6115241 Ref: sysvar_ndb_join_pushdown6116155 Ref: sysvar_ndb_log_apply_status6121571 Ref: sysvar_ndb_log_bin6122576 Ref: sysvar_ndb_log_binlog_index6123620 Ref: sysvar_ndb_optimized_node_selection6124783 Ref: sysvar_ndb_report_thresh_binlog_epoch_slip6128410 Ref: sysvar_ndb_report_thresh_binlog_mem_usage6129323 Ref: sysvar_slave_allow_batching6130191 Ref: sysvar_ndb_table_no_logging6131318 Ref: sysvar_ndb_table_temporary6133453 Ref: sysvar_ndb_use_copying_alter_table6134293 Ref: sysvar_ndb_use_exact_count6134847 Ref: sysvar_ndb_use_transactions6135609 Ref: sysvar_ndbinfo_database6136713 Ref: sysvar_ndbinfo_max_bytes6137561 Ref: sysvar_ndbinfo_max_rows6138317 Ref: sysvar_ndbinfo_show_hidden6139068 Ref: sysvar_ndbinfo_table_prefix6139964 Ref: sysvar_ndbinfo_version6141147 Ref: sysvar_server_id_bits6141715 Node: mysql-cluster-status-variables6143035 Ref: statvar_Handler_discover6143563 Ref: statvar_Ndb_cluster_node_id6143865 Ref: statvar_Ndb_config_from_host6144109 Ref: statvar_Ndb_config_from_port6144520 Ref: statvar_Ndb_conflict_fn_max6144947 Ref: statvar_Ndb_conflict_fn_old6145417 Ref: statvar_Ndb_execute_count6145871 Ref: statvar_Ndb_number_of_data_nodes6146046 Ref: statvar_Ndb_pushed_queries_defined6146388 Ref: statvar_Ndb_pushed_queries_dropped6146685 Ref: statvar_Ndb_pushed_queries_executed6146863 Ref: statvar_Ndb_pushed_reads6147046 Ref: statvar_Slave_heartbeat_period6147379 Ref: statvar_Slave_received_heartbeats6147558 Ref: statvar_Ndb_pruned_scan_count6147890 Ref: statvar_Ndb_scan_count6148478 Node: mysql-cluster-interconnects6148751 Node: mysql-cluster-sci-sockets6151377 Node: mysql-cluster-interconnects-performance6153648 Node: mysql-cluster-programs6157879 Node: mysql-cluster-programs-mysqld6161373 Node: mysql-cluster-programs-ndbd6166432 Ref: option_ndbd_bind-address6170128 Ref: option_ndbd_daemon6170755 Ref: option_ndbd_initial6171530 Ref: option_ndbd_initial-start6173991 Ref: option_ndbd_nowait-nodes6175663 Ref: option_ndbd_nodaemon6177162 Ref: option_ndbd_nostart6178258 Ref: option_ndbd_install6179224 Ref: option_ndbd_remove6181064 Node: mysql-cluster-programs-ndbmtd6187558 Ref: ndbparam-ndbmtd-maxnoofexecutionthreads6191132 Node: mysql-cluster-programs-ndb-mgmd6196185 Ref: option_ndb_mgmd_bind-address6200574 Ref: option_ndb_mgmd_configdir6201614 Ref: option_ndb_mgmd_config-cache6203307 Ref: option_ndb_mgmd_config-file6206027 Ref: option_ndb_mgmd_daemon6207523 Ref: option_ndb_mgmd_initial6208177 Ref: option_ndb_mgmd_log-name6209613 Ref: option_ndb_mgmd_nodaemon6210150 Ref: option_ndb_mgmd_print-full-config6211063 Ref: option_ndb_mgmd_reload6211914 Ref: option_ndb_mgmd_nowait-nodes6213293 Ref: option_ndb_mgmd_install6220182 Ref: option_ndb_mgmd_remove6221955 Node: mysql-cluster-programs-ndb-mgm6222864 Ref: option_ndb_mgm_execute6224658 Ref: option_ndb_mgm_try-reconnect6225673 Node: mysql-cluster-programs-ndb-config6226508 Ref: option_ndb_config_usage6229404 Ref: option_ndb_config_version6229763 Ref: option_ndb_config_ndb-connectstring6230074 Ref: option_ndb_config_config-file6230977 Ref: option_ndb_config_query6231333 Ref: option_ndb_config_host6232428 Ref: option_ndb_config_id6233693 Ref: option_ndb_config_nodeid6233711 Ref: option_ndb_config_nodes6233917 Ref: option_ndb_config_type6234636 Ref: option_ndb_config_fields6235289 Ref: option_ndb_config_rows6235977 Ref: option_ndb_config_configinfo6236647 Ref: option_ndb_config_xml6238461 Node: mysql-cluster-programs-ndb-cpcd6246100 Node: mysql-cluster-programs-ndb-delete-all6246861 Node: mysql-cluster-programs-ndb-desc6247936 Ref: option_ndb_desc_extra-partition-info6254164 Ref: option_ndb_desc_blob-info6254267 Ref: option_ndb_desc_extra-node-info6254612 Node: mysql-cluster-programs-ndb-drop-index6255180 Node: mysql-cluster-programs-ndb-drop-table6257567 Node: mysql-cluster-programs-ndb-error-reporter6258429 Ref: option_ndb_error_reporter_fs6259647 Node: mysql-cluster-programs-ndb-print-backup-file6260271 Node: mysql-cluster-programs-ndb-print-schema-file6261894 Node: mysql-cluster-programs-ndb-print-sys-file6263289 Node: mysql-cluster-programs-ndbd-redo-log-reader6264967 Ref: option_ndbd_redo_log_reader_noprint6267601 Ref: option_ndbd_redo_log_reader_nocheck6267995 Node: mysql-cluster-programs-ndb-restore6268716 Ref: option_ndb_restore_connect6278191 Ref: option_ndb_restore_nodeid6279325 Ref: option_ndb_restore_skip-table-check6279972 Ref: option_ndb_restore_promote-attributes6281861 Ref: option_ndb_restore_lossy-conversions6283458 Ref: option_ndb_restore_preserve-trailing-spaces6284527 Ref: option_ndb_restore_backupid6285218 Ref: option_ndb_restore_restore_epoch6285753 Ref: option_ndb_restore_backup_path6286170 Ref: option_ndb_restore_no-upgrade6289131 Ref: option_ndb_restore_print_data6289699 Ref: option_ndb_restore_tab6290299 Ref: option_ndb_restore_fields-enclosed-by6290761 Ref: option_ndb_restore_fields-optionally-enclosed-by6291322 Ref: option_ndb_restore_fields-terminated-by6292034 Ref: option_ndb_restore_hex6292647 Ref: option_ndb_restore_lines-terminated-by6292901 Ref: option_ndb_restore_append6293511 Ref: option_ndb_restore_include-databases6294393 Ref: option_ndb_restore_include-tables6294833 Ref: option_ndb_restore_exclude-databases6298026 Ref: option_ndb_restore_exclude-tables6298466 Ref: option_ndb_restore_exclude-missing-columns6303503 Ref: option_ndb_restore_disable-indexes6304420 Ref: option_ndb_restore_rebuild-indexes6305153 Ref: option_ndb_restore_skip-broken-objects6305683 Ref: option_ndb_restore_skip-unknown-objects6306392 Ref: option_ndb_restore_rewrite-database6307084 Node: mysql-cluster-programs-ndb-select-all6310282 Ref: option_ndb_restore_order6311105 Node: mysql-cluster-programs-ndb-select-count6315003 Node: mysql-cluster-programs-ndb-show-tables6316108 Ref: option_ndb_show_tables_database6317811 Ref: option_ndb_show_tables_loops6317909 Ref: option_ndb_show_tables_parsable6318126 Ref: option_ndb_show_tables_show-temp-status6318276 Ref: option_ndb_show_tables_type6318370 Ref: option_ndb_show_tables_unqualified6318719 Node: mysql-cluster-programs-ndb-size-pl6319200 Ref: option_ndb_size_pl_options6323250 Ref: option_ndb_size_pl_debugging6327879 Ref: option_ndb_size_pl_format6328204 Node: mysql-cluster-programs-ndb-waiter6329503 Ref: mysql-cluster-programs-ndb-waiter-additional-options6331233 Ref: option_ndb_waiter_no-contact6331262 Ref: option_ndb_waiter_not-started6331485 Ref: option_ndb_waiter_timeout6331704 Ref: option_ndb_waiter_single-user6331913 Ref: option_ndb_waiter_nowait-nodes6332003 Ref: option_ndb_waiter_wait-nodes6332413 Node: mysql-cluster-program-options-common6334599 Ref: option_ndb_common_help6337439 Ref: option_ndb_common_character-sets-dir6337751 Ref: option_ndb_common_connect-string6338254 Ref: option_ndb_common_core-file6339023 Ref: option_ndb_common_debug6340083 Ref: option_ndb_common_mgmd-host6340669 Ref: option_ndb_common_ndb-nodeid6340801 Ref: option_ndb_common_ndb-optimized-node-selection6341422 Ref: option_ndb_common_version6341910 Node: mysql-cluster-management6342562 Node: mysql-cluster-start-phases6346810 Node: mysql-cluster-mgm-client-commands6354219 Node: mysql-cluster-backup6365600 Node: mysql-cluster-backup-concepts6366996 Node: mysql-cluster-backup-using-management-client6368847 Node: mysql-cluster-backup-configuration6377796 Node: mysql-cluster-backup-troubleshooting6378956 Node: mysql-cluster-rolling-restart6380100 Node: mysql-cluster-event-reports6388194 Node: mysql-cluster-logging-management-commands6393378 Node: mysql-cluster-log-events6396908 Node: mysql-cluster-log-statistics6407738 Node: mysql-cluster-logs-ndb-messages6416513 Node: mysql-cluster-logs-cluster-log6417147 Node: mysql-cluster-ndb-transporter-errors6463270 Node: mysql-cluster-single-user-mode6469373 Node: mysql-cluster-sql-statements6471782 Node: mysql-cluster-ndbinfo6479529 Node: mysql-cluster-ndbinfo-blocks6489499 Node: mysql-cluster-ndbinfo-config-params6490626 Node: mysql-cluster-ndbinfo-counters6491727 Node: mysql-cluster-ndbinfo-diskpagebuffer6494874 Node: mysql-cluster-ndbinfo-logbuffers6498244 Node: mysql-cluster-ndbinfo-logspaces6499293 Node: mysql-cluster-ndbinfo-memoryusage6500327 Node: mysql-cluster-ndbinfo-nodes6506674 Node: mysql-cluster-ndbinfo-pools6513437 Node: mysql-cluster-ndbinfo-resources6520099 Node: mysql-cluster-ndbinfo-transporters6521571 Node: mysql-cluster-security6525662 Node: mysql-cluster-security-networking-issues6526571 Node: mysql-cluster-security-mysql-privileges6536501 Node: mysql-cluster-security-mysql-security-procedures6545228 Node: mysql-cluster-disk-data6549506 Node: mysql-cluster-disk-data-objects6551249 Node: mysql-cluster-disk-data-symlinks6564595 Node: mysql-cluster-disk-data-storage-requirements6569622 Node: mysql-cluster-online-add-node6571686 Node: mysql-cluster-online-add-node-remarks6572774 Node: mysql-cluster-online-add-node-basics6582914 Node: mysql-cluster-online-add-node-example6587400 Node: mysql-cluster-privilege-distribution6609222 Node: mysql-cluster-replication6618896 Ref: mysql-cluster-replication-ndb-non-ndb6622529 Node: mysql-cluster-replication-abbreviations6623144 Node: mysql-cluster-replication-general6624734 Node: mysql-cluster-replication-issues6628419 Ref: mysql-cluster-replication-issues-filtering6643511 Node: mysql-cluster-replication-schema6648192 Node: mysql-cluster-replication-preparation6658037 Node: mysql-cluster-replication-starting6663838 Node: mysql-cluster-replication-two-channels6668732 Node: mysql-cluster-replication-failover6671579 Node: mysql-cluster-replication-backups6675045 Node: mysql-cluster-replication-auto-sync6683654 Node: mysql-cluster-replication-pitr6689785 Node: mysql-cluster-replication-multi-master6693306 Node: mysql-cluster-replication-conflict-resolution6700561 Ref: option_mysqld_ndb-log-updated-only6705154 Ref: option_mysqld_ndb-log-update-as-write6706403 Ref: mysql-cluster-ndb-replication-table6707407 Ref: mysql-cluster-replication-ndb-old6710445 Ref: mysql-cluster-replication-ndb-max6711371 Ref: mysql-cluster-replication-ndb-max-delete-win6712271 Node: mysql-cluster-news6720902 Node: mysql-cluster-news-7-26723077 Node: mysql-cluster-news-5-1-51-ndb-7-2-06723734 Node: mysql-cluster-news-7-16729175 Node: mysql-cluster-news-5-1-56-ndb-7-1-166731978 Node: mysql-cluster-news-5-1-56-ndb-7-1-156733473 Node: mysql-cluster-news-5-1-56-ndb-7-1-146738377 Node: mysql-cluster-news-5-1-56-ndb-7-1-136743917 Node: mysql-cluster-news-5-1-51-ndb-7-1-126748442 Node: mysql-cluster-news-5-1-51-ndb-7-1-116752829 Node: mysql-cluster-news-5-1-51-ndb-7-1-106759538 Node: mysql-cluster-news-5-1-51-ndb-7-1-9a6776699 Node: mysql-cluster-news-5-1-51-ndb-7-1-96778263 Node: mysql-cluster-news-5-1-47-ndb-7-1-86789849 Node: mysql-cluster-news-5-1-47-ndb-7-1-76801051 Node: mysql-cluster-news-5-1-47-ndb-7-1-66805231 Node: mysql-cluster-news-5-1-47-ndb-7-1-56811110 Node: mysql-cluster-news-5-1-44-ndb-7-1-4b6816814 Node: mysql-cluster-news-5-1-44-ndb-7-1-4a6818908 Node: mysql-cluster-news-5-1-44-ndb-7-1-46821462 Node: mysql-cluster-news-5-1-44-ndb-7-1-36832409 Node: mysql-cluster-news-5-1-41-ndb-7-1-26843018 Node: mysql-cluster-news-5-1-41-ndb-7-1-16853304 Node: mysql-cluster-news-5-1-39-ndb-7-1-06857259 Node: mysql-cluster-news-7-06860067 Node: mysql-cluster-news-5-1-56-ndb-7-0-276866372 Node: mysql-cluster-news-5-1-56-ndb-7-0-266867946 Node: mysql-cluster-news-5-1-56-ndb-7-0-256872929 Node: mysql-cluster-news-5-1-56-ndb-7-0-246877878 Node: mysql-cluster-news-5-1-51-ndb-7-0-236882482 Node: mysql-cluster-news-5-1-51-ndb-7-0-226886315 Node: mysql-cluster-news-5-1-51-ndb-7-0-216893118 Node: mysql-cluster-news-5-1-51-ndb-7-0-20a6910381 Node: mysql-cluster-news-5-1-51-ndb-7-0-206911768 Node: mysql-cluster-news-5-1-47-ndb-7-0-196923791 Node: mysql-cluster-news-5-1-47-ndb-7-0-186935081 Node: mysql-cluster-news-5-1-47-ndb-7-0-176939167 Node: mysql-cluster-news-5-1-47-ndb-7-0-166945137 Node: mysql-cluster-news-5-1-44-ndb-7-0-15b6951312 Node: mysql-cluster-news-5-1-44-ndb-7-0-15a6953029 Node: mysql-cluster-news-5-1-44-ndb-7-0-156955421 Node: mysql-cluster-news-5-1-44-ndb-7-0-146965407 Node: mysql-cluster-news-5-1-41-ndb-7-0-136978385 Node: mysql-cluster-news-5-1-41-ndb-7-0-12b6984841 Node: mysql-cluster-news-5-1-41-ndb-7-0-12a6987014 Node: mysql-cluster-news-5-1-41-ndb-7-0-126989104 Node: mysql-cluster-news-5-1-41-ndb-7-0-11b6991613 Node: mysql-cluster-news-5-1-41-ndb-7-0-11a6993336 Node: mysql-cluster-news-5-1-41-ndb-7-0-116995098 Node: mysql-cluster-news-5-1-39-ndb-7-0-107002784 Node: mysql-cluster-news-5-1-39-ndb-7-0-9b7019989 Node: mysql-cluster-news-5-1-39-ndb-7-0-9a7021882 Node: mysql-cluster-news-5-1-39-ndb-7-0-97023739 Node: mysql-cluster-news-5-1-37-ndb-7-0-8a7041738 Node: mysql-cluster-news-5-1-37-ndb-7-0-87043674 Node: mysql-cluster-news-5-1-35-ndb-7-0-77061886 Node: mysql-cluster-news-5-1-34-ndb-7-0-67076297 Node: mysql-cluster-news-5-1-32-ndb-7-0-57086175 Node: mysql-cluster-news-5-1-32-ndb-7-0-47094811 Node: mysql-cluster-news-5-1-32-ndb-6-4-37101102 Node: mysql-cluster-news-5-1-31-ndb-6-4-27112808 Node: mysql-cluster-news-5-1-31-ndb-6-4-17115185 Node: mysql-cluster-news-5-1-30-ndb-6-4-07120992 Node: mysql-cluster-news-6-37127377 Node: mysql-cluster-news-5-1-56-ndb-6-3-457133781 Node: mysql-cluster-news-5-1-56-ndb-6-3-447136866 Node: mysql-cluster-news-5-1-56-ndb-6-3-437138348 Node: mysql-cluster-news-5-1-51-ndb-6-3-427139779 Node: mysql-cluster-news-5-1-51-ndb-6-3-417142305 Node: mysql-cluster-news-5-1-51-ndb-6-3-407143907 Node: mysql-cluster-news-5-1-51-ndb-6-3-397152026 Node: mysql-cluster-news-5-1-47-ndb-6-3-387160313 Node: mysql-cluster-news-5-1-47-ndb-6-3-377168604 Node: mysql-cluster-news-5-1-47-ndb-6-3-367171558 Node: mysql-cluster-news-5-1-47-ndb-6-3-357176888 Node: mysql-cluster-news-5-1-44-ndb-6-3-347181536 Node: mysql-cluster-news-5-1-44-ndb-6-3-337187559 Node: mysql-cluster-news-5-1-41-ndb-6-3-327196429 Node: mysql-cluster-news-5-1-41-ndb-6-3-31b7201755 Node: mysql-cluster-news-5-1-41-ndb-6-3-31a7203480 Node: mysql-cluster-news-5-1-41-ndb-6-3-317205410 Node: mysql-cluster-news-5-1-39-ndb-6-3-307211483 Node: mysql-cluster-news-5-1-39-ndb-6-3-297212976 Node: mysql-cluster-news-5-1-39-ndb-6-3-28b7225466 Node: mysql-cluster-news-5-1-39-ndb-6-3-28a7227139 Node: mysql-cluster-news-5-1-39-ndb-6-3-287228988 Node: mysql-cluster-news-5-1-37-ndb-6-3-27a7240654 Node: mysql-cluster-news-5-1-37-ndb-6-3-277242359 Node: mysql-cluster-news-5-1-35-ndb-6-3-267255161 Node: mysql-cluster-news-5-1-34-ndb-6-3-257262735 Node: mysql-cluster-news-5-1-32-ndb-6-3-247269075 Node: mysql-cluster-news-5-1-32-ndb-6-3-237276451 Node: mysql-cluster-news-5-1-31-ndb-6-3-227284175 Node: mysql-cluster-news-5-1-31-ndb-6-3-217287192 Node: mysql-cluster-news-5-1-30-ndb-6-3-207292760 Node: mysql-cluster-news-5-1-29-ndb-6-3-197298070 Node: mysql-cluster-news-5-1-28-ndb-6-3-187307309 Node: mysql-cluster-news-5-1-27-ndb-6-3-177311962 Node: mysql-cluster-news-5-1-24-ndb-6-3-167317632 Node: mysql-cluster-news-5-1-24-ndb-6-3-157320843 Node: mysql-cluster-news-5-1-24-ndb-6-3-147325104 Node: mysql-cluster-news-5-1-24-ndb-6-3-137329164 Node: mysql-cluster-news-5-1-23-ndb-6-3-127336796 Node: mysql-cluster-news-5-1-23-ndb-6-3-117337577 Node: mysql-cluster-news-5-1-23-ndb-6-3-107338346 Node: mysql-cluster-news-5-1-23-ndb-6-3-97339903 Node: mysql-cluster-news-5-1-23-ndb-6-3-87344116 Node: mysql-cluster-news-5-1-23-ndb-6-3-77352219 Node: mysql-cluster-news-5-1-22-ndb-6-3-67357067 Node: mysql-cluster-news-5-1-22-ndb-6-3-57362182 Node: mysql-cluster-news-5-1-22-ndb-6-3-47363808 Node: mysql-cluster-news-5-1-22-ndb-6-3-37370756 Node: mysql-cluster-news-5-1-22-ndb-6-3-27373371 Node: mysql-cluster-news-5-1-19-ndb-6-3-17379052 Node: mysql-cluster-news-5-1-19-ndb-6-3-07380323 Node: mysql-cluster-news-6-27383086 Node: mysql-cluster-news-5-1-51-ndb-6-2-197385891 Node: mysql-cluster-news-5-1-34-ndb-6-2-187420706 Node: mysql-cluster-news-5-1-32-ndb-6-2-177428858 Node: mysql-cluster-news-5-1-28-ndb-6-2-167448345 Node: mysql-cluster-news-5-1-23-ndb-6-2-157456415 Node: mysql-cluster-news-5-1-23-ndb-6-2-147457102 Node: mysql-cluster-news-5-1-23-ndb-6-2-137472718 Node: mysql-cluster-news-5-1-23-ndb-6-2-127474006 Node: mysql-cluster-news-5-1-23-ndb-6-2-117477708 Node: mysql-cluster-news-5-1-23-ndb-6-2-107482227 Node: mysql-cluster-news-5-1-22-ndb-6-2-97484398 Node: mysql-cluster-news-5-1-22-ndb-6-2-87487558 Node: mysql-cluster-news-5-1-22-ndb-6-2-77491121 Node: mysql-cluster-news-5-1-22-ndb-6-2-67494338 Node: mysql-cluster-news-5-1-22-ndb-6-2-57497449 Node: mysql-cluster-news-5-1-19-ndb-6-2-47504385 Node: mysql-cluster-news-5-1-19-ndb-6-2-37506195 Node: mysql-cluster-news-5-1-18-ndb-6-2-27508005 Node: mysql-cluster-news-5-1-18-ndb-6-2-17509902 Node: mysql-cluster-news-5-1-16-ndb-6-2-07511686 Node: mysql-cluster-news-6-17514303 Node: mysql-cluster-news-5-1-15-ndb-6-1-237517891 Node: mysql-cluster-news-5-1-15-ndb-6-1-227519377 Node: mysql-cluster-news-5-1-15-ndb-6-1-217520871 Node: mysql-cluster-news-5-1-15-ndb-6-1-207522252 Node: mysql-cluster-news-5-1-15-ndb-6-1-197523649 Node: mysql-cluster-news-5-1-15-ndb-6-1-187525136 Node: mysql-cluster-news-5-1-15-ndb-6-1-177526862 Node: mysql-cluster-news-5-1-15-ndb-6-1-167528309 Node: mysql-cluster-news-5-1-15-ndb-6-1-157530226 Node: mysql-cluster-news-5-1-15-ndb-6-1-147531460 Node: mysql-cluster-news-5-1-15-ndb-6-1-137532883 Node: mysql-cluster-news-5-1-15-ndb-6-1-127534402 Node: mysql-cluster-news-5-1-15-ndb-6-1-117536223 Node: mysql-cluster-news-5-1-15-ndb-6-1-107538355 Node: mysql-cluster-news-5-1-15-ndb-6-1-97541057 Node: mysql-cluster-news-5-1-15-ndb-6-1-87542497 Node: mysql-cluster-news-5-1-15-ndb-6-1-77544458 Node: mysql-cluster-news-5-1-15-ndb-6-1-67549146 Node: mysql-cluster-news-5-1-15-ndb-6-1-57552795 Node: mysql-cluster-news-5-1-15-ndb-6-1-47555076 Node: mysql-cluster-news-5-1-15-ndb-6-1-37558387 Node: mysql-cluster-news-5-1-15-ndb-6-1-27562364 Node: mysql-cluster-news-5-1-15-ndb-6-1-17563657 Node: mysql-cluster-news-5-1-14-ndb-6-1-07565602 Node: mysql-cluster-news-series7569367 Node: mysql-cluster-news-7-1-series7570646 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.56-ndb-7.1.157572312 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.56-ndb-7.1.147576044 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.56-ndb-7.1.137579297 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.51-ndb-7.1.127583107 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.51-ndb-7.1.117585144 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.51-ndb-7.1.107591045 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.51-ndb-7.1.97608104 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.47-ndb-7.1.87617072 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.47-ndb-7.1.77625583 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.47-ndb-7.1.67628152 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.47-ndb-7.1.57632868 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.44-ndb-7.1.47637210 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.44-ndb-7.1.37646787 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.41-ndb-7.1.27655665 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.41-ndb-7.1.17665268 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.39-ndb-7.1.07667812 Node: mysql-cluster-news-7-0-series7668483 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.56-ndb-7.0.267670935 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.56-ndb-7.0.257674667 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.56-ndb-7.0.247677250 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.51-ndb-7.0.237681060 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.51-ndb-7.0.227683097 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.51-ndb-7.0.217688549 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.51-ndb-7.0.20a7704866 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.47-ndb-7.0.197705101 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.47-ndb-7.0.187713614 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.47-ndb-7.0.177716003 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.47-ndb-7.0.167720721 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.44-ndb-7.0.15b7725850 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.44-ndb-7.0.147726396 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.41-ndb-7.0.137737362 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.41-ndb-7.0.127742972 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.41-ndb-7.0.117744040 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.39-ndb-7.0.107748469 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.39-ndb-7.0.9a7763748 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.37-ndb-7.0.8a7764132 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.35-ndb-7.0.77764489 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.34-ndb-7.0.67775596 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.32-ndb-7.0.57784097 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.32-ndb-7.0.47791773 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.32-ndb-6.4.37796923 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.31-ndb-6.4.27806523 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.31-ndb-6.4.17807685 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.30-ndb-6.4.07811251 Node: mysql-cluster-news-6-3-series7815394 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.56-ndb-6.3.457818744 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.56-ndb-6.3.447820669 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.56-ndb-6.3.437820987 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.51-ndb-6.3.427821250 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.51-ndb-6.3.417822211 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.51-ndb-6.3.407822639 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.51-ndb-6.3.397829406 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.47-ndb-6.3.387835735 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.47-ndb-6.3.377841328 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.47-ndb-6.3.367842664 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.47-ndb-6.3.357846268 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.44-ndb-6.3.347849950 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.44-ndb-6.3.337855373 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.41-ndb-6.3.327861718 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.41-ndb-6.3.31a7866277 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.39-ndb-6.3.307866549 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.39-ndb-6.3.297866867 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.39-ndb-6.3.28a7878208 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.37-ndb-6.3.277878594 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.35-ndb-6.3.267887768 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.34-ndb-6.3.257894574 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.32-ndb-6.3.247900014 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.32-ndb-6.3.237906414 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.31-ndb-6.3.227912436 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.31-ndb-6.3.217914499 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.30-ndb-6.3.207918948 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.29-ndb-6.3.197921995 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.28-ndb-6.3.187930220 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.27-ndb-6.3.177933671 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.24-ndb-6.3.167937798 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.24-ndb-6.3.157939951 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.24-ndb-6.3.147942513 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.24-ndb-6.3.137944679 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.23-ndb-6.3.107949632 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.23-ndb-6.3.97950071 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.23-ndb-6.3.87952751 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.23-ndb-6.3.77958632 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.22-ndb-6.3.67961497 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.22-ndb-6.3.57964584 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.22-ndb-6.3.47964952 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.22-ndb-6.3.37967519 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.22-ndb-6.3.27968607 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.19-ndb-6.3.07971688 Node: mysql-cluster-news-6-2-series7973035 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.34-ndb-6.2.187974829 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.32-ndb-6.2.177982081 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.28-ndb-6.2.167998904 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.23-ndb-6.2.148005331 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.23-ndb-6.2.138006800 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.23-ndb-6.2.128007139 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.23-ndb-6.2.118009474 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.23-ndb-6.2.108012498 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.22-ndb-6.2.98013714 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.22-ndb-6.2.88015250 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.22-ndb-6.2.78017207 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.22-ndb-6.2.68018429 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.22-ndb-6.2.58020223 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.19-ndb-6.2.48025371 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.19-ndb-6.2.38026148 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.18-ndb-6.2.28033275 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.18-ndb-6.2.18034231 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.16-ndb-6.2.08034721 Node: mysql-cluster-news-6-1-series8035967 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.15-ndb-6.1.238038392 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.15-ndb-6.1.228038602 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.15-ndb-6.1.218038821 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.15-ndb-6.1.198039137 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.15-ndb-6.1.188039415 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.15-ndb-6.1.178039944 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.15-ndb-6.1.168040114 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.15-ndb-6.1.158040972 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.15-ndb-6.1.148041147 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.15-ndb-6.1.138041509 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.15-ndb-6.1.128041771 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.15-ndb-6.1.118042464 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.15-ndb-6.1.108043393 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.15-ndb-6.1.98044904 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.15-ndb-6.1.88045289 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.15-ndb-6.1.78045995 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.15-ndb-6.1.68048895 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.15-ndb-6.1.58051268 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.15-ndb-6.1.48052491 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.15-ndb-6.1.38054358 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.15-ndb-6.1.28057152 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.15-ndb-6.1.18057381 Ref: dynxml-auto-changelog-difflist-mysqld-5.1.14-ndb-6.1.08058480 Node: partitioning8061170 Node: partitioning-overview8068112 Node: partitioning-types8077553 Node: partitioning-range8083981 Node: partitioning-list8093561 Node: partitioning-hash8099535 Node: partitioning-linear-hash8106254 Node: partitioning-key8109126 Node: partitioning-subpartitions8114308 Node: partitioning-handling-nulls8123884 Node: partitioning-management8138483 Node: partitioning-management-range-list8142464 Node: partitioning-management-hash-key8159257 Node: partitioning-maintenance8162121 Node: partitioning-info8165536 Node: partitioning-pruning8171894 Node: partitioning-limitations8184515 Ref: partitioning-limitations-file-system-ops8191028 Ref: partitioning-limitations-max-partitions8193285 Ref: partitioning-limitations-subpartitions8196609 Node: partitioning-limitations-partitioning-keys-unique-keys8200807 Node: partitioning-limitations-storage-engines8209507 Node: partitioning-limitations-functions8212789 Ref: partitioning-limitations-ceiling-floor8214309 Ref: partitioning-limitations-extract8214905 Node: stored-programs-views8215394 Node: stored-programs-defining8217715 Node: stored-routines8220737 Node: stored-routines-syntax8224013 Node: stored-routines-privileges8227128 Node: stored-routines-metadata8228761 Node: stored-routines-last-insert-id8230015 Node: triggers8231011 Node: trigger-syntax8233173 Node: trigger-metadata8241146 Node: events8241555 Node: events-overview8243528 Node: events-configuration8247886 Ref: events-event-scheduler-option8248419 Node: events-syntax8255495 Node: events-metadata8256617 Node: events-status-info8260176 Node: events-privileges8262920 Node: views8271651 Node: view-syntax8272870 Node: view-algorithms8274221 Node: view-updatability8277862 Node: view-metadata8283892 Node: stored-programs-security8284289 Node: stored-programs-logging8290367 Node: information-schema8311678 Node: schemata-table8321958 Node: tables-table8322884 Node: columns-table8327430 Node: statistics-table8330026 Node: user-privileges-table8332015 Node: schema-privileges-table8333054 Node: table-privileges-table8334183 Node: column-privileges-table8335436 Node: character-sets-table8337187 Node: collations-table8338082 Node: collation-character-set-applicability-table8339726 Node: table-constraints-table8340539 Node: key-column-usage-table8341923 Node: routines-table8344556 Node: views-table8347358 Node: triggers-table8351772 Node: plugins-table8357462 Node: engines-table8360674 Node: partitions-table8361645 Node: events-table8373317 Node: files-table8384172 Node: processlist-table8400873 Node: referential-constraints-table8402883 Node: status-table8404816 Node: variables-table8406099 Node: profiling-table8407556 Node: other-information-schema-tables8410613 Node: extended-show8411001 Node: connectors-apis8417122 Ref: connectors-apis-summary8422457 Ref: connectors-apis-versions8427409 Node: connector-odbc8428764 Node: connector-odbc-versions8431877 Node: connector-odbc-introduction8434674 Node: connector-odbc-general-information8435587 Node: connector-odbc-architecture8436449 Node: connector-odbc-driver-manager8440267 Node: connector-odbc-installation8441987 Node: connector-odbc-installation-binary-windows8445737 Node: connector-odbc-installation-binary-windows-installer8447752 Node: connector-odbc-installation-binary-windows-dll8450000 Node: connector-odbc-installation-binary-unix8453241 Node: connector-odbc-installation-binary-unix-tarball8454149 Node: connector-odbc-installation-binary-unix-rpm8455236 Node: connector-odbc-installation-binary-macosx8456572 Node: connector-odbc-installation-source-windows8461127 Node: connector-odbc-installation-source-windows-3-51-building8462687 Node: connector-odbc-installation-source-windows-3-51-testing8465048 Node: connector-odbc-installation-source-unix8465527 Node: connector-odbc-installation-source-unix-configure-options8468523 Node: connector-odbc-installation-source-unix-otheroptions8471095 Node: connector-odbc-installation-source-unix-building8473266 Node: connector-odbc-installation-source-unix-shared-libraries8473845 Node: connector-odbc-installation-source-unix-installing8476391 Node: connector-odbc-installation-source-unix-testing8477389 Node: connector-odbc-installation-source-unix-macosx8478232 Node: connector-odbc-installation-source-unix-hpux8480205 Node: connector-odbc-installation-source-unix-aix8481563 Node: connector-odbc-installation-source-development8482370 Node: connector-odbc-configuration8484995 Node: connector-odbc-configuration-dsn8486441 Node: connector-odbc-configuration-connection-parameters8487870 Node: connector-odbc-configuration-dsn-windows8503651 Node: connector-odbc-configuration-dsn-windows-3-518507249 Node: connector-odbc-configuration-dsn-windows-5-18510715 Node: connector-odbc-configuration-dsn-windows-problems8514180 Node: connector-odbc-configuration-dsn-macosx8515521 Node: connector-odbc-configuration-dsn-unix8518390 Node: connector-odbc-configuration-connection-without-dsn8520367 Node: connector-odbc-configuration-connection-pooling8521890 Node: connector-odbc-configuration-trace8522661 Node: connector-odbc-configuration-trace-windows8523488 Node: connector-odbc-configuration-trace-macosx8524564 Node: connector-odbc-configuration-trace-unix8525296 Node: connector-odbc-configuration-trace-log8526335 Node: connector-odbc-examples8527433 Node: connector-odbc-examples-overview8528577 Node: connector-odbc-examples-walkthrough8529335 Node: connector-odbc-examples-tools8531489 Node: connector-odbc-examples-tools-with-access8534045 Node: connector-odbc-examples-tools-with-access-export8534908 Node: connector-odbc-examples-tools-with-access-import8536739 Node: connector-odbc-examples-tools-with-access-linked-tables8537987 Node: connector-odbc-examples-tools-with-wordexcel8541476 Node: connector-odbc-examples-tools-with-crystalreports8544700 Node: connector-odbc-examples-programming8549432 Node: connector-odbc-examples-programming-vb8550251 Node: connector-odbc-examples-programming-vb-ado8550976 Node: connector-odbc-examples-programming-vb-dao8553903 Node: connector-odbc-examples-programming-vb-rdo8556332 Node: connector-odbc-examples-programming-net8558518 Node: connector-odbc-examples-programming-net-csharp8559078 Node: connector-odbc-examples-programming-net-vb8565026 Node: connector-odbc-reference8569009 Node: connector-odbc-reference-api8569683 Node: connector-odbc-reference-datatypes8581196 Node: connector-odbc-reference-errorcodes8584176 Node: connector-odbc-usagenotes8587410 Node: connector-odbc-usagenotes-functionality8588084 Node: connector-odbc-usagenotes-functionality-last-insert-id8588845 Node: connector-odbc-usagenotes-functionality-dynamic-cursor8590452 Node: connector-odbc-usagenotes-functionality-performance8591141 Node: connector-odbc-usagenotes-functionality-query-timeout8592736 Node: connector-odbc-usagenotes-apptips8593261 Node: connector-odbc-usagenotes-apptips-microsoft8594767 Node: connector-odbc-usagenotes-apptips-microsoft-access8596017 Node: connector-odbc-usagenotes-apptips-microsoft-excel8600522 Node: connector-odbc-usagenotes-apptips-microsoft-visualbasic8601731 Node: connector-odbc-usagenotes-apptips-microsoft-visualinterdev8602502 Node: connector-odbc-usagenotes-apptips-microsoft-visualobjects8603096 Node: connector-odbc-usagenotes-apptips-microsoft-ado8603469 Node: connector-odbc-usagenotes-apptips-microsoft-asp8605070 Node: connector-odbc-usagenotes-apptips-microsoft-vb-asp8605993 Node: connector-odbc-usagenotes-apptips-borland8606727 Node: connector-odbc-usagenotes-apptips-borland-builder8607636 Node: connector-odbc-usagenotes-apptips-borland-delphi8608195 Node: connector-odbc-usagenotes-apptips-borland-cppbuilder8610184 Node: connector-odbc-usagenotes-apptips-coldfusion8610707 Node: connector-odbc-usagenotes-apptips-openoffice8612128 Node: connector-odbc-usagenotes-apptips-sambarserver8612673 Node: connector-odbc-usagenotes-apptips-datajunction8613135 Node: connector-odbc-usagenotes-apptips-vision8613645 Node: connector-odbc-errors8613973 Ref: qandaitem-21-1-7-3-1-18618320 Ref: qandaitem-21-1-7-3-1-28619282 Ref: qandaitem-21-1-7-3-1-38619631 Ref: qandaitem-21-1-7-3-1-48620413 Ref: qandaitem-21-1-7-3-1-58622413 Ref: qandaitem-21-1-7-3-1-68622811 Ref: qandaitem-21-1-7-3-1-78623069 Ref: qandaitem-21-1-7-3-1-88623361 Ref: qandaitem-21-1-7-3-1-98623624 Ref: qandaitem-21-1-7-3-1-108623946 Ref: qandaitem-21-1-7-3-1-118624410 Ref: qandaitem-21-1-7-3-1-128625133 Ref: qandaitem-21-1-7-3-1-138625440 Ref: qandaitem-21-1-7-3-1-148625819 Ref: qandaitem-21-1-7-3-1-158626218 Ref: qandaitem-21-1-7-3-1-168626629 Ref: qandaitem-21-1-7-3-1-178627178 Ref: qandaitem-21-1-7-3-1-188627530 Ref: qandaitem-21-1-7-3-1-198627930 Ref: qandaitem-21-1-7-3-1-208628487 Ref: qandaitem-21-1-7-3-1-218628895 Ref: qandaitem-21-1-7-3-1-228629450 Ref: qandaitem-21-1-7-3-1-238629748 Ref: qandaitem-21-1-7-3-1-248630318 Node: connector-odbc-support8630697 Node: connector-odbc-support-community8631499 Node: connector-odbc-support-bug-report8632415 Node: connector-odbc-support-patch-submission8634927 Node: connector-odbc-support-changehistory8635345 Node: connector-odbc-support-credits8635732 Node: connector-net8636083 Node: connector-net-versions8639028 Node: connector-net-installation8643767 Node: connector-net-installation-windows8644588 Node: connector-net-installation-binary-windows-installer8645343 Node: connector-net-installation-binary-windows-zip8649695 Node: connector-net-installation-unix8652330 Node: connector-net-installation-source8654548 Node: connector-net-visual-studio8656775 Node: connector-net-visual-studio-making-a-connection8659810 Ref: connector-net-visual-studio-add-connection8660638 Ref: connector-net-visual-studio-choose-data-source8660941 Ref: connector-net-visual-studio-add-connection-dialog8661275 Ref: connector-net-visual-studio-new-data-connection8661867 Node: connector-net-visual-studio-editing-tables8662482 Ref: connector-net-visual-studio-editing-new-table8663820 Ref: connector-net-visual-studio-choose-table-name8664898 Ref: connector-net-visual-studio-newly-created-table8664996 Ref: connector-net-visual-studio-table-desginer-menu-item8665167 Node: connector-net-visual-studio-editing-tables-column-editor8665211 Node: connector-net-visual-studio-editing-tables-indexes8666540 Ref: connector-net-visual-studio-indexes-dialog8667117 Node: connector-net-visual-studio-editing-tables-foreign-keys8667440 Ref: connector-net-visual-studio-foreign-key-relationships8668418 Node: connector-net-visual-studio-editing-tables-column-details8668470 Node: connector-net-visual-studio-editing-tables-table-properties8669047 Ref: connector-net-visual-studio-table-properties-menu8669477 Ref: connector-net-visual-studio-selecting-table-properties8669843 Node: connector-net-visual-studio-editing-views8669879 Ref: connector-net-visual-studio-views-edit-sql8670353 Ref: connector-net-visual-studio-views-sql-added8670432 Ref: connector-net-visual-studio-views-sql-saved8671269 Node: connector-net-visual-studio-editing-stored-procedures-and-functions8671303 Ref: connector-net-visual-studio-stored-procedure-edit8671860 Ref: connector-net-visual-studio-stored-procedure-saved8673385 Node: connector-net-visual-studio-editing-triggers8673431 Node: connector-net-visual-studio-editing-user-defined-functions-udf8675116 Node: connector-net-visual-studio-cloning-database-objects8676526 Node: connector-net-visual-studio-dropping-database-objects8677532 Node: connector-net-visual-studio-entity-framework8678190 Node: connector-net-website-config8679941 Ref: connector-net-website-config-tool8680740 Ref: connector-net-website-config-tool-membership8680889 Ref: connector-net-website-config-tool-string-editor8681289 Ref: connector-net-website-config-tool-options8682282 Ref: connector-net-website-config-tool-roles8682515 Ref: connector-net-website-config-tool-profiles8682740 Ref: connector-net-website-config-tool-session-state8682931 Ref: connector-net-website-config-tool-tables8683514 Node: connector-net-sql-editor8683575 Ref: connector-net-sql-editor-new-file-dialog8684001 Ref: connector-net-sql-editor-query8684780 Node: connector-net-ddl-t4-ef8684938 Ref: connector-net-ddl-t4-ef-properties8685589 Ref: connector-net-ddl-t4-ef-generate8685882 Node: connector-net-tutorials8685950 Node: connector-net-tutorials-intro8687102 Node: connector-net-tutorials-connection8688808 Node: connector-net-tutorials-sql-command8691129 Node: connector-net-tutorials-data-adapter8697077 Ref: connector-net-tutorials-18704146 Node: connector-net-tutorials-parameters8704192 Node: connector-net-tutorials-stored-procedures8707515 Node: connector-net-tutorials-asp-roles8711387 Ref: connector-net-tutorials-authentication-type8717229 Ref: connector-net-tutorials-select-provider8717559 Ref: connector-net-tutorials-tables8717856 Ref: connector-net-tutorials-security-tab8718536 Ref: connector-net-tutorials-create-user8718889 Ref: connector-net-tutorials-users-roles-tables8719082 Node: connector-net-tutorials-asp-provider-session-state8719283 Node: connector-net-tutorials-asp-provider-profile8725790 Ref: connector-net-tutorials-asp-provider-profile-simple-app8729090 Node: connector-net-tutorials-entity-framework-winform-data-source8731495 Ref: connector-net-visual-studio-entity-framework-add-entity-data-model8733056 Ref: connector-net-visual-studio-entity-framework-entity-data-model-wizard-18733313 Ref: connector-net-visual-studio-entity-framework-entity-data-model-wizard-28733709 Ref: connector-net-visual-studio-entity-framework-entity-data-model-wizard-38734370 Ref: connector-net-visual-studio-entity-framework-entity-data-model-diagram8734493 Ref: connector-net-visual-studio-entity-framework-data-source-configuration-wizard-18734971 Ref: connector-net-visual-studio-entity-framework-data-source-configuration-wizard-28735276 Ref: connector-net-visual-studio-entity-framework-data-source-configuration-wizard-38735437 Ref: connector-net-visual-studio-entity-framework-data-sources8735744 Ref: connector-net-visual-studio-entity-framework-data-form-design8736239 Ref: connector-net-visual-studio-entity-framework-form-add-code8736704 Ref: connector-net-visual-studio-entity-framework-app-running-18736882 Ref: connector-net-visual-studio-entity-framework-save-enabled8737509 Ref: connector-net-visual-studio-entity-framework-form-add-code-save8737760 Node: connector-net-tutorials-entity-framework-databinding-linq-entities8737965 Ref: connector-net-visual-studio-entity-framework-tutorial-linq-18739384 Ref: connector-net-visual-studio-entity-framework-tutorial-linq-28739663 Ref: connector-net-visual-studio-entity-framework-tutorial-linq-38739992 Ref: connector-net-visual-studio-entity-framework-tutorial-linq-48740090 Ref: connector-net-visual-studio-entity-framework-tutorial-linq-58740242 Ref: connector-net-visual-studio-entity-framework-tutorial-linq-68744283 Ref: connector-net-visual-studio-entity-framework-tutorial-linq-78744452 Node: connector-net-tutorials-ssl8744663 Node: connector-net-tutorials-mysqlscript8751318 Node: connector-net-tutorials-mysqlscript-delimiter8756978 Node: connector-net-tutorials-efmodel-ddl8760848 Node: connector-net-programming8763002 Node: connector-net-programming-connecting8765657 Node: connector-net-programming-connecting-connection-string8766398 Node: connector-net-programming-connecting-open8767977 Node: connector-net-programming-connecting-errors8770488 Node: connector-net-programming-getschema8773262 Node: connector-net-programming-getschema-collections8774817 Node: connector-net-programming-mysqlcommand8777527 Node: connector-net-programming-connection-pooling8780881 Node: connector-net-programming-prepared8783751 Node: connector-net-programming-prepared-preparing8784916 Node: connector-net-programming-stored8787548 Node: connector-net-programming-stored-using8789865 Node: connector-net-programming-blob8798232 Node: connector-net-programming-blob-serverprep8799353 Node: connector-net-programming-blob-writing8801497 Node: connector-net-programming-blob-reading8805041 Node: connector-net-programming-crystal8808865 Node: connector-net-programming-crystal-source8809588 Node: connector-net-programming-crystal-creating8813083 Node: connector-net-programming-crystal-displaying8814188 Node: connector-net-programming-datetime8821919 Node: connector-net-programming-datetime-problems8822909 Node: connector-net-programming-datetime-restricting8823606 Node: connector-net-programming-datetime-invalid8824656 Node: connector-net-programming-datetime-null8826402 Node: connector-net-programming-asp-provider8827445 Node: connector-net-programming-binary-issues8835389 Node: connector-using-character-sets8837313 Node: content-advanced-topics-medium-trust8838957 Node: connector-net-programming-tracing8840102 Node: connector-net-programming-tracing-mysql8845235 Node: connector-net-programming-tracing-mysql-custom-listeners8852514 Node: connector-net-programming-bulk-loader8856422 Node: connector-net-connection-options8859993 Node: connector-net-ref8883311 Node: connector-net-ref-mysqlclient8883795 Node: connector-net-ref-mysqlclienthierarchy8888914 Node: connector-net-ref-mysqlclient-mysqlcommand8889278 Node: connector-net-ref-mysqlclient-mysqlcommandmembers8890460 Node: connector-net-ref-mysqlclient-mysqlcommandconstructor8896185 Node: connector-net-ref-mysqlclient-mysqlcommandconstructor18897711 Node: connector-net-ref-mysqlclient-mysqlcommandconstructor28898521 Node: connector-net-ref-mysqlclient-mysqlcommandconstructor38899304 Node: connector-net-ref-mysqlclient-mysqlconnection8900233 Node: connector-net-ref-mysqlclient-mysqlconnectionmembers8901437 Node: connector-net-ref-mysqlclient-mysqlconnectionconstructor8907648 Node: connector-net-ref-mysqlclient-mysqlconnectionconstructor18908817 Node: connector-net-ref-mysqlclient-mysqlconnectionconstructor28909662 Node: connector-net-ref-mysqlclient-mysqlconnection-connectionstring8910414 Node: connector-net-ref-mysqlclient-mysqlconnection-connectiontimeout8911190 Node: connector-net-ref-mysqlclient-mysqlconnection-database8911972 Node: connector-net-ref-mysqlclient-mysqlconnection-datasource8912696 Node: connector-net-ref-mysqlclient-mysqlconnection-serverthread8913376 Node: connector-net-ref-mysqlclient-mysqlconnection-serverversion8914080 Node: connector-net-ref-mysqlclient-mysqlconnection-state8914716 Node: connector-net-ref-mysqlclient-mysqlconnection-usecompression8915449 Node: connector-net-ref-mysqlclient-mysqlconnection-begintransaction-overloads8916192 Node: connector-net-ref-mysqlclient-mysqlconnection-begintransaction-overload-18917277 Node: connector-net-ref-mysqlclient-mysqltransaction8918261 Node: connector-net-ref-mysqlclient-mysqltransactionmembers8919481 Node: connector-net-ref-mysqlclient-mysqltransaction-connection8921952 Node: connector-net-ref-mysqlclient-mysqltransaction-isolationlevel8923264 Node: connector-net-ref-mysqlclient-mysqltransaction-commit8924315 Node: connector-net-ref-mysqlclient-mysqltransaction-rollback8925034 Node: connector-net-ref-mysqlclient-mysqlconnection-begintransaction-overload-28925695 Node: connector-net-ref-mysqlclient-mysqlconnection-changedatabase8926586 Node: connector-net-ref-mysqlclient-mysqlconnection-close8927437 Node: connector-net-ref-mysqlclient-mysqlconnection-createcommand8928144 Node: connector-net-ref-mysqlclient-mysqlconnection-open8928805 Node: connector-net-ref-mysqlclient-mysqlconnection-ping8929495 Node: connector-net-ref-mysqlclient-mysqlconnection-infomessage8930126 Node: connector-net-ref-mysqlclient-mysqlinfomessageeventhandler8930926 Node: connector-net-ref-mysqlclient-mysqlinfomessageeventargs8932076 Node: connector-net-ref-mysqlclient-mysqlinfomessageeventargsmembers8933379 Node: connector-net-ref-mysqlclient-mysqlinfomessageeventargsconstructor8935880 Node: connector-net-ref-mysqlclient-mysqlinfomessageeventargs-errors8936704 Node: connector-net-ref-mysqlclient-mysqlerror8937406 Node: connector-net-ref-mysqlclient-mysqlerrormembers8938502 Node: connector-net-ref-mysqlclient-mysqlerrorconstructor8940909 Node: connector-net-ref-mysqlclient-mysqlerror-code8941688 Node: connector-net-ref-mysqlclient-mysqlerror-level8942257 Node: connector-net-ref-mysqlclient-mysqlerror-message8942830 Node: connector-net-ref-mysqlclient-mysqlconnection-statechange8943359 Node: connector-net-ref-mysqlclient-mysqlcommandconstructor48943976 Node: connector-net-ref-mysqlclient-mysqlcommand-commandtext8944842 Node: connector-net-ref-mysqlclient-mysqlcommand-commandtimeout8945556 Node: connector-net-ref-mysqlclient-mysqlcommand-commandtype8946287 Node: connector-net-ref-mysqlclient-mysqlcommand-connection8947023 Node: connector-net-ref-mysqlclient-mysqlcommand-isprepared8947644 Node: connector-net-ref-mysqlclient-mysqlcommand-parameters8948249 Node: connector-net-ref-mysqlclient-mysqlparametercollection8948995 Node: connector-net-ref-mysqlclient-mysqlparametercollectionmembers8950592 Node: connector-net-ref-mysqlclient-mysqlparametercollectionconstructor8956931 Node: connector-net-ref-mysqlclient-mysqlparametercollection-count8957743 Node: connector-net-ref-mysqlclient-mysqlparametercollectionitem8958542 Node: connector-net-ref-mysqlclient-mysqlparameter8960053 Node: connector-net-ref-mysqlclient-mysqlparametermembers8961556 Node: connector-net-ref-mysqlclient-mysqlparameterconstructor8967870 Node: connector-net-ref-mysqlclient-mysqlparameterconstructor18970979 Node: connector-net-ref-mysqlclient-mysqlparameterconstructor38971763 Node: connector-net-ref-mysqlclient-mysqldbtype8973037 Node: connector-net-ref-mysqlclient-mysqlparameterconstructor48979365 Node: connector-net-ref-mysqlclient-mysqlparameterconstructor68980767 Node: connector-net-ref-mysqlclient-mysqlparameter-value8983572 Node: connector-net-ref-mysqlclient-mysqlparameterconstructor58984244 Node: connector-net-ref-mysqlclient-mysqlparameterconstructor28985730 Node: connector-net-ref-mysqlclient-mysqlparameter-dbtype8986884 Node: connector-net-ref-mysqlclient-mysqlparameter-direction8987632 Node: connector-net-ref-mysqlclient-mysqlparameter-isnullable8988598 Node: connector-net-ref-mysqlclient-mysqlparameter-isunsigned8989395 Node: connector-net-ref-mysqlclient-mysqlparameter-mysqldbtype8990009 Node: connector-net-ref-mysqlclient-mysqlparameter-parametername8990693 Node: connector-net-ref-mysqlclient-mysqlparameter-precision8991483 Node: connector-net-ref-mysqlclient-mysqlparameter-scale8992338 Node: connector-net-ref-mysqlclient-mysqlparameter-size8993150 Node: connector-net-ref-mysqlclient-mysqlparameter-sourcecolumn8993903 Node: connector-net-ref-mysqlclient-mysqlparameter-sourceversion8994814 Node: connector-net-ref-mysqlclient-mysqlparameter-tostring8995704 Node: connector-net-ref-mysqlclient-mysqlparametercollection-item18996429 Node: connector-net-ref-mysqlclient-mysqlparametercollection-item28997374 Node: connector-net-ref-mysqlclient-mysqlparametercollection-add-overloads8998269 Node: connector-net-ref-mysqlclient-mysqlparametercollection-add-overload-29001797 Node: connector-net-ref-mysqlclient-mysqlparametercollection-add-overload-19003169 Node: connector-net-ref-mysqlclient-mysqlparametercollection-add-overload-49004590 Node: connector-net-ref-mysqlclient-mysqlparametercollection-add-overload-59006080 Node: connector-net-ref-mysqlclient-mysqlparametercollection-add-overload-69007676 Node: connector-net-ref-mysqlclient-mysqlparametercollection-add-overload-39009414 Node: connector-net-ref-mysqlclient-mysqlparametercollection-clear9010915 Node: connector-net-ref-mysqlclient-mysqlparametercollection-contains-overloads9011722 Node: connector-net-ref-mysqlclient-mysqlparametercollection-contains-overload-19013154 Node: connector-net-ref-mysqlclient-mysqlparametercollection-contains-overload-29014550 Node: connector-net-ref-mysqlclient-mysqlparametercollection-copyto9015920 Node: connector-net-ref-mysqlclient-mysqlparametercollection-indexof-overloads9016953 Node: connector-net-ref-mysqlclient-mysqlparametercollection-indexof-overload-19018372 Node: connector-net-ref-mysqlclient-mysqlparametercollection-indexof-overload-29019768 Node: connector-net-ref-mysqlclient-mysqlparametercollection-insert9021194 Node: connector-net-ref-mysqlclient-mysqlparametercollection-remove9022188 Node: connector-net-ref-mysqlclient-mysqlparametercollection-removeat-overloads9023108 Node: connector-net-ref-mysqlclient-mysqlparametercollection-removeat-overload-19024487 Node: connector-net-ref-mysqlclient-mysqlparametercollection-removeat-overload-29025711 Node: connector-net-ref-mysqlclient-mysqlcommand-transaction9026963 Node: connector-net-ref-mysqlclient-mysqlcommand-updatedrowsource9027598 Node: connector-net-ref-mysqlclient-mysqlcommand-cancel9028372 Node: connector-net-ref-mysqlclient-mysqlcommand-createparameter9029378 Node: connector-net-ref-mysqlclient-mysqlcommand-executenonquery9030316 Node: connector-net-ref-mysqlclient-mysqlcommand-executereader-overloads9031091 Node: connector-net-ref-mysqlclient-mysqlcommand-executereader-overload-19032108 Node: connector-net-ref-mysqlclient-mysqldatareader9033030 Node: connector-net-ref-mysqlclient-mysqldatareadermembers9034446 Node: connector-net-ref-mysqlclient-mysqldatareader-depth9045305 Node: connector-net-ref-mysqlclient-mysqldatareader-fieldcount9046121 Node: connector-net-ref-mysqlclient-mysqldatareader-hasrows9046888 Node: connector-net-ref-mysqlclient-mysqldatareader-isclosed9047576 Node: connector-net-ref-mysqlclient-mysqldatareaderitem9048340 Node: connector-net-ref-mysqlclient-mysqldatareader-item19049590 Node: connector-net-ref-mysqlclient-mysqldatareader-item29050620 Node: connector-net-ref-mysqlclient-mysqldatareader-recordsaffected9051591 Node: connector-net-ref-mysqlclient-mysqldatareader-close9052431 Node: connector-net-ref-mysqlclient-mysqldatareader-getboolean9053170 Node: connector-net-ref-mysqlclient-mysqldatareader-getbyte9054059 Node: connector-net-ref-mysqlclient-mysqldatareader-getbytes9054927 Node: connector-net-ref-mysqlclient-mysqldatareader-getchar9056441 Node: connector-net-ref-mysqlclient-mysqldatareader-getchars9057319 Node: connector-net-ref-mysqlclient-mysqldatareader-getdatatypename9058576 Node: connector-net-ref-mysqlclient-mysqldatareader-getdatetime9059494 Node: connector-net-ref-mysqlclient-mysqldatareader-getdecimal9060317 Node: connector-net-ref-mysqlclient-mysqldatareader-getdouble9061130 Node: connector-net-ref-mysqlclient-mysqldatareader-getfieldtype9061936 Node: connector-net-ref-mysqlclient-mysqldatareader-getfloat9062839 Node: connector-net-ref-mysqlclient-mysqldatareader-getguid9063634 Node: connector-net-ref-mysqlclient-mysqldatareader-getint169064416 Node: connector-net-ref-mysqlclient-mysqldatareader-getint329065206 Node: connector-net-ref-mysqlclient-mysqldatareader-getint649065997 Node: connector-net-ref-mysqlclient-mysqldatareader-getmysqldatetime9066794 Node: connector-net-ref-mysqlclient-mysqldatareader-getname9067541 Node: connector-net-ref-mysqlclient-mysqldatareader-getordinal9068410 Node: connector-net-ref-mysqlclient-mysqldatareader-getschematable9069320 Node: connector-net-ref-mysqlclient-mysqldatareader-getstring9070199 Node: connector-net-ref-mysqlclient-mysqldatareader-gettimespan9071008 Node: connector-net-ref-mysqlclient-mysqldatareader-getuint169071723 Node: connector-net-ref-mysqlclient-mysqldatareader-getuint329072426 Node: connector-net-ref-mysqlclient-mysqldatareader-getuint649073125 Node: connector-net-ref-mysqlclient-mysqldatareader-getvalue9073824 Node: connector-net-ref-mysqlclient-mysqldatareader-getvalues9074714 Node: connector-net-ref-mysqlclient-mysqldatareader-isdbnull9075633 Node: connector-net-ref-mysqlclient-mysqldatareader-nextresult9076546 Node: connector-net-ref-mysqlclient-mysqldatareader-read9077399 Node: connector-net-ref-mysqlclient-mysqlcommand-executereader-overload-29078107 Node: connector-net-ref-mysqlclient-mysqlcommand-executescalar9078956 Node: connector-net-ref-mysqlclient-mysqlcommand-prepare9079711 Node: connector-net-ref-mysqlclient-mysqlcommandbuilder9080338 Node: connector-net-ref-mysqlclient-mysqlcommandbuildermembers9081532 Node: connector-net-ref-mysqlclient-mysqlcommandbuilder-deriveparameters-overloads9086762 Node: connector-net-ref-mysqlclient-mysqlcommandbuilder-deriveparameters-overload-19088407 Node: connector-net-ref-mysqlclient-mysqlcommandbuilder-deriveparameters-overload-29090087 Node: connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor9091051 Node: connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor19092777 Node: connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor39093676 Node: connector-net-ref-mysqlclient-mysqldataadapter9094629 Node: connector-net-ref-mysqlclient-mysqldataadaptermembers9095796 Node: connector-net-ref-mysqlclient-mysqldataadapterconstructor9104512 Node: connector-net-ref-mysqlclient-mysqldataadapterconstructor19106144 Node: connector-net-ref-mysqlclient-mysqldataadapterconstructor29107004 Node: connector-net-ref-mysqlclient-mysqldataadapterconstructor39107841 Node: connector-net-ref-mysqlclient-mysqldataadapterconstructor49108753 Node: connector-net-ref-mysqlclient-mysqldataadapter-deletecommand19109592 Node: connector-net-ref-mysqlclient-mysqldataadapter-insertcommand19110266 Node: connector-net-ref-mysqlclient-mysqldataadapter-selectcommand19110944 Node: connector-net-ref-mysqlclient-mysqldataadapter-updatecommand19111622 Node: connector-net-ref-mysqlclient-mysqldataadapter-rowupdated9112296 Node: connector-net-ref-mysqlclient-mysqlrowupdatedeventhandler9114744 Node: connector-net-ref-mysqlclient-mysqlrowupdatedeventargs9115814 Node: connector-net-ref-mysqlclient-mysqlrowupdatedeventargsmembers9117147 Node: connector-net-ref-mysqlclient-mysqlrowupdatedeventargsconstructor9120394 Node: connector-net-ref-mysqlclient-mysqlrowupdatedeventargs-command19121729 Node: connector-net-ref-mysqlclient-mysqldataadapter-rowupdating9122410 Node: connector-net-ref-mysqlclient-mysqlrowupdatingeventhandler9124575 Node: 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connector-net-ref-mysqlclient-mysqlexception9138370 Node: connector-net-ref-mysqlclient-mysqlexceptionmembers9139616 Node: connector-net-ref-mysqlclient-mysqlexception-number9143067 Node: connector-net-ref-mysqlclient-mysqlhelper9143647 Node: connector-net-ref-mysqlclient-mysqlhelpermembers9144780 Node: connector-net-ref-mysqlclient-mysqlhelper-executedatarow9148378 Node: connector-net-ref-mysqlclient-mysqlhelper-executedataset-overloads9149665 Node: connector-net-ref-mysqlclient-mysqlhelper-executedataset-overload-39152177 Node: connector-net-ref-mysqlclient-mysqlhelper-executedataset-overload-49153597 Node: connector-net-ref-mysqlclient-mysqlhelper-executedataset-overload-19155189 Node: connector-net-ref-mysqlclient-mysqlhelper-executedataset-overload-29156494 Node: connector-net-ref-mysqlclient-mysqlhelper-executenonquery-overloads9157894 Node: connector-net-ref-mysqlclient-mysqlhelper-executenonquery-overload-19159637 Node: 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Ref: qandaitem-B-4-1-2110281601 Ref: qandaitem-B-4-1-2210281768 Ref: qandaitem-B-4-1-2310282076 Ref: qandaitem-B-4-1-2410282447 Ref: qandaitem-B-4-1-2510282866 Ref: qandaitem-B-4-1-2610283621 Ref: qandaitem-B-4-1-2710284951 Ref: qandaitem-B-4-1-2810285129 Node: faqs-triggers10285784 Ref: qandaitem-B-5-1-110286781 Ref: qandaitem-B-5-1-210286878 Ref: qandaitem-B-5-1-310287005 Ref: qandaitem-B-5-1-410287277 Ref: qandaitem-B-5-1-510287495 Ref: qandaitem-B-5-1-610287935 Ref: qandaitem-B-5-1-710288551 Ref: qandaitem-B-5-1-810288687 Ref: qandaitem-B-5-1-910288747 Ref: qandaitem-B-5-1-1010289041 Ref: qandaitem-B-5-1-1110289261 Ref: qandaitem-B-5-1-1210289471 Ref: qandaitem-B-5-1-1310290237 Node: faqs-views10292377 Ref: qandaitem-B-6-1-110292947 Ref: qandaitem-B-6-1-210293035 Ref: qandaitem-B-6-1-310293181 Ref: qandaitem-B-6-1-410293511 Ref: qandaitem-B-6-1-510293568 Ref: qandaitem-B-6-1-610293628 Node: faqs-information-schema10293910 Ref: qandaitem-B-7-1-110294603 Ref: qandaitem-B-7-1-210294726 Ref: qandaitem-B-7-1-310294877 Ref: qandaitem-B-7-1-410295270 Ref: qandaitem-B-7-1-510295648 Node: faqs-migration10295969 Ref: qandaitem-B-8-1-110296374 Ref: qandaitem-B-8-1-210296907 Node: faqs-security10297886 Ref: qandaitem-B-9-1-110298522 Ref: qandaitem-B-9-1-210299090 Ref: qandaitem-B-9-1-310299559 Ref: qandaitem-B-9-1-410299946 Ref: qandaitem-B-9-1-510300050 Node: faqs-mysql-cluster10300154 Ref: qandaitem-B-10-1-110304213 Ref: qandaitem-B-10-1-210305607 Ref: qandaitem-B-10-1-310306430 Ref: qandaitem-B-10-1-410306934 Ref: qandaitem-B-10-1-510308339 Ref: qandaitem-B-10-1-610308990 Ref: qandaitem-B-10-1-710309730 Ref: qandaitem-B-10-1-810312086 Ref: qandaitem-B-10-1-910314514 Ref: qandaitem-B-10-1-1010315080 Ref: qandaitem-B-10-1-1110316025 Ref: qandaitem-B-10-1-1210320026 Ref: qandaitem-B-10-1-1310321123 Ref: qandaitem-B-10-1-1410321737 Ref: qandaitem-B-10-1-1510322745 Ref: qandaitem-B-10-1-1610323825 Ref: qandaitem-B-10-1-1710324638 Ref: qandaitem-B-10-1-1810325035 Ref: qandaitem-B-10-1-1910325321 Ref: qandaitem-B-10-1-2010326039 Ref: qandaitem-B-10-1-2110326533 Ref: qandaitem-B-10-1-2210326805 Ref: qandaitem-B-10-1-2310328693 Ref: qandaitem-B-10-1-2410329234 Ref: qandaitem-B-10-1-2510331920 Ref: qandaitem-B-10-1-2610332822 Ref: qandaitem-B-10-1-2710333458 Ref: qandaitem-B-10-1-2810335264 Ref: qandaitem-B-10-1-2910336357 Ref: qandaitem-B-10-1-3010338691 Ref: qandaitem-B-10-1-3110338927 Ref: qandaitem-B-10-1-3210339403 Ref: qandaitem-B-10-1-3310339908 Ref: qandaitem-B-10-1-3410340610 Ref: qandaitem-B-10-1-3510340982 Ref: qandaitem-B-10-1-3610341442 Ref: qandaitem-B-10-1-3710342067 Ref: qandaitem-B-10-1-3810342342 Ref: qandaitem-B-10-1-3910342836 Node: faqs-cjk10344482 Ref: qandaitem-B-11-1-110346729 Ref: qandaitem-B-11-1-210349655 Ref: qandaitem-B-11-1-310355262 Ref: qandaitem-B-11-1-410356267 Ref: qandaitem-B-11-1-510359145 Ref: qandaitem-B-11-1-610359462 Ref: qandaitem-B-11-1-710359876 Ref: qandaitem-B-11-1-810360113 Ref: qandaitem-B-11-1-910361023 Ref: qandaitem-B-11-1-1010362777 Ref: qandaitem-B-11-1-1110365488 Ref: qandaitem-B-11-1-1210369968 Ref: qandaitem-B-11-1-1310371873 Ref: qandaitem-B-11-1-1410374725 Ref: qandaitem-B-11-1-1510378069 Ref: qandaitem-B-11-1-1610380014 Ref: qandaitem-B-11-1-1710381209 Ref: qandaitem-B-11-1-1810381681 Ref: qandaitem-B-11-1-1910382306 Ref: qandaitem-B-11-1-2010382626 Node: faqs-connectors-apis10383083 Node: faqs-replication10383611 Node: faqs-mysql-drbd-heartbeat10383905 Node: faqs-drbd10384674 Ref: qandaitem-B-14-1-1-110385414 Ref: qandaitem-B-14-1-1-210385871 Ref: qandaitem-B-14-1-1-310386370 Ref: qandaitem-B-14-1-1-410386443 Ref: qandaitem-B-14-1-1-510386542 Ref: qandaitem-B-14-1-1-610386714 Node: drbd-linux-heartbeat10386855 Ref: qandaitem-B-14-2-1-110387370 Ref: qandaitem-B-14-2-1-210387464 Ref: qandaitem-B-14-2-1-310387575 Node: drbd-architecture10387759 Ref: qandaitem-B-14-3-1-110388579 Ref: qandaitem-B-14-3-1-210388748 Ref: qandaitem-B-14-3-1-310388986 Ref: qandaitem-B-14-3-1-410389431 Ref: qandaitem-B-14-3-1-510389877 Ref: qandaitem-B-14-3-1-610390040 Ref: qandaitem-B-14-3-1-710390202 Node: drbd-mysql-replication-scale10390647 Ref: qandaitem-B-14-4-1-110391243 Ref: qandaitem-B-14-4-1-210391715 Ref: qandaitem-B-14-4-1-310392178 Node: drbd-file-systems10393266 Ref: qandaitem-B-14-5-1-110393656 Node: drbd-lvm10393770 Ref: qandaitem-B-14-6-1-110394279 Ref: qandaitem-B-14-6-1-210394529 Ref: qandaitem-B-14-6-1-310394846 Node: drbd-virtualization10395059 Ref: qandaitem-B-14-7-1-110395491 Ref: qandaitem-B-14-7-1-210395603 Node: drbd-security10395835 Ref: qandaitem-B-14-8-1-110396289 Ref: qandaitem-B-14-8-1-210396483 Node: drbd-system-requirements10396624 Ref: qandaitem-B-14-9-1-110397170 Ref: qandaitem-B-14-9-1-210398033 Ref: qandaitem-B-14-9-1-310398366 Node: drbd-support-consulting10398562 Ref: qandaitem-B-14-10-1-110399454 Ref: qandaitem-B-14-10-1-210399800 Ref: qandaitem-B-14-10-1-310400373 Ref: qandaitem-B-14-10-1-410400630 Ref: qandaitem-B-14-10-1-510400911 Ref: qandaitem-B-14-10-1-610401043 Node: error-handling10401259 Node: error-sources10402137 Node: error-types10403772 Node: error-messages-server10405335 Ref: error_er_hashchk10407638 Ref: error_er_nisamchk10407715 Ref: error_er_no10407793 Ref: error_er_yes10407860 Ref: error_er_cant_create_file10407929 Ref: error_er_cant_create_table10408042 Ref: error_er_cant_create_db10408157 Ref: error_er_db_create_exists10408272 Ref: error_er_db_drop_exists10408394 Ref: error_er_db_drop_delete10408519 Ref: error_er_db_drop_rmdir10408650 Ref: error_er_cant_delete_file10408779 Ref: error_er_cant_find_system_rec10408893 Ref: error_er_cant_get_stat10409009 Ref: error_er_cant_get_wd10409121 Ref: error_er_cant_lock10409234 Ref: error_er_cant_open_file10409333 Ref: error_er_file_not_found10409443 Ref: error_er_cant_read_dir10409553 Ref: error_er_cant_set_wd10409663 Ref: error_er_checkread10409773 Ref: error_er_disk_full10409893 Ref: error_er_dup_key10410022 Ref: error_er_error_on_close10410132 Ref: error_er_error_on_read10410243 Ref: error_er_error_on_rename10410354 Ref: error_er_error_on_write10410475 Ref: error_er_file_used10410587 Ref: error_er_filsort_abort10410688 Ref: error_er_form_not_found10410776 Ref: error_er_get_errno10410885 Ref: error_er_illegal_ha10410989 Ref: error_er_key_not_found10411116 Ref: error_er_not_form_file10411217 Ref: error_er_not_keyfile10411328 Ref: error_er_old_keyfile10411453 Ref: error_er_open_as_readonly10411566 Ref: error_er_outofmemory10411668 Ref: error_er_out_of_sortmemory10411808 Ref: error_er_unexpected_eof10411940 Ref: error_er_con_count_error10412072 Ref: error_er_out_of_resources10412170 Ref: error_er_bad_host_error10412441 Ref: error_er_handshake_error10412553 Ref: error_er_dbaccess_denied_error10412644 Ref: error_er_access_denied_error10412777 Ref: error_er_no_db_error10412912 Ref: error_er_unknown_com_error10413006 Ref: error_er_bad_null_error10413101 Ref: error_er_bad_db_error10413204 Ref: error_er_table_exists_error10413300 Ref: error_er_bad_table_error10413406 Ref: error_er_non_uniq_error10413502 Ref: error_er_server_shutdown10413609 Ref: error_er_bad_field_error10413714 Ref: error_er_wrong_field_with_group10413819 Ref: error_er_wrong_group_field10413926 Ref: error_er_wrong_sum_select10414025 Ref: error_er_wrong_value_count10414161 Ref: error_er_too_long_ident10414279 Ref: error_er_dup_fieldname10414388 Ref: error_er_dup_keyname10414490 Ref: error_er_dup_entry10414587 Ref: error_er_wrong_field_spec10414690 Ref: error_er_parse_error10414811 Ref: error_er_empty_query10414908 Ref: error_er_nonuniq_table10414997 Ref: error_er_invalid_default10415101 Ref: error_er_multiple_pri_key10415209 Ref: error_er_too_many_keys10415316 Ref: error_er_too_many_key_parts10415436 Ref: error_er_too_long_key10415567 Ref: error_er_key_column_does_not_exits10415696 Ref: error_er_blob_used_as_key10415822 Ref: error_er_too_big_fieldlength10415982 Ref: error_er_wrong_auto_key10416144 Ref: error_er_ready10416319 Ref: error_er_normal_shutdown10416454 Ref: error_er_got_signal10416551 Ref: error_er_shutdown_complete10416652 Ref: error_er_forcing_close10416753 Ref: error_er_ipsock_error10416871 Ref: error_er_no_such_index10416968 Ref: error_er_wrong_field_terminators10417126 Ref: error_er_blobs_and_no_terminated10417283 Ref: error_er_textfile_not_readable10417449 Ref: error_er_file_exists_error10417607 Ref: error_er_load_info10417711 Ref: error_er_alter_info10417835 Ref: error_er_wrong_sub_key10417936 Ref: error_er_cant_remove_all_fields10418179 Ref: error_er_cant_drop_field_or_key10418338 Ref: error_er_insert_info10418468 Ref: error_er_update_table_used10418584 Ref: error_er_no_such_thread10418730 Ref: error_er_kill_denied_error10418829 Ref: error_er_no_tables_used10418940 Ref: error_er_too_big_set10419031 Ref: error_er_no_unique_logfile10419143 Ref: error_er_table_not_locked_for_write10419270 Ref: error_er_table_not_locked10419423 Ref: error_er_blob_cant_have_default10419544 Ref: error_er_wrong_db_name10419677 Ref: error_er_wrong_table_name10419781 Ref: error_er_too_big_select10419885 Ref: error_er_unknown_error10420122 Ref: error_er_unknown_procedure10420211 Ref: error_er_wrong_paramcount_to_procedure10420313 Ref: error_er_wrong_parameters_to_procedure10420453 Ref: error_er_unknown_table10420588 Ref: error_er_field_specified_twice10420688 Ref: error_er_invalid_group_func_use10420799 Ref: error_er_unsupported_extension10420913 Ref: error_er_table_must_have_columns10421071 Ref: error_er_record_file_full10421192 Ref: error_er_unknown_character_set10421293 Ref: error_er_too_many_tables10421404 Ref: error_er_too_many_fields10421537 Ref: error_er_too_big_rowsize10421631 Ref: error_er_stack_overrun10421861 Ref: error_er_wrong_outer_join10422056 Ref: error_er_null_column_in_index10422204 Ref: error_er_cant_find_udf10422406 Ref: error_er_cant_initialize_udf10422506 Ref: error_er_udf_no_paths10422622 Ref: error_er_udf_exists10422732 Ref: error_er_cant_open_library10422833 Ref: error_er_cant_find_dl_entry10422958 Ref: error_er_function_not_defined10423072 Ref: error_er_host_is_blocked10423183 Ref: error_er_host_not_privileged10423359 Ref: error_er_password_anonymous_user10423497 Ref: error_er_password_not_allowed10423684 Ref: error_er_password_no_match10423877 Ref: error_er_update_info10424002 Ref: error_er_cant_create_thread10424120 Ref: error_er_wrong_value_count_on_row10424347 Ref: error_er_cant_reopen_table10424483 Ref: error_er_invalid_use_of_null10424587 Ref: error_er_regexp_error10424694 Ref: error_er_mix_of_group_func_and_fields10424795 Ref: error_er_nonexisting_grant10425009 Ref: error_er_tableaccess_denied_error10425146 Ref: error_er_columnaccess_denied_error10425283 Ref: error_er_illegal_grant_for_table10425441 Ref: error_er_grant_wrong_host_or_user10425623 Ref: error_er_no_such_table10425756 Ref: error_er_nonexisting_table_grant10425859 Ref: error_er_not_allowed_command10426021 Ref: error_er_syntax_error10426158 Ref: error_er_delayed_cant_change_lock10426371 Ref: error_er_too_many_delayed_threads10426525 Ref: error_er_aborting_connection10426643 Ref: error_er_net_packet_too_large10426775 Ref: error_er_net_read_error_from_pipe10426909 Ref: error_er_net_fcntl_error10427037 Ref: error_er_net_packets_out_of_order10427140 Ref: error_er_net_uncompress_error10427251 Ref: error_er_net_read_error10427374 Ref: error_er_net_read_interrupted10427493 Ref: error_er_net_error_on_write10427617 Ref: error_er_net_write_interrupted10427740 Ref: error_er_too_long_string10427865 Ref: error_er_table_cant_handle_blob10427998 Ref: error_er_table_cant_handle_auto_increment10428136 Ref: error_er_delayed_insert_table_locked10428294 Ref: error_er_wrong_column_name10428471 Ref: error_er_wrong_key_column10428577 Ref: error_er_wrong_mrg_table10428703 Ref: error_er_dup_unique10428885 Ref: error_er_blob_key_without_length10429014 Ref: error_er_primary_cant_have_null10429173 Ref: error_er_too_many_rows10429353 Ref: error_er_requires_primary_key10429466 Ref: error_er_no_raid_compiled10429587 Ref: error_er_update_without_key_in_safe_mode10429721 Ref: error_er_key_does_not_exits10429926 Ref: error_er_check_no_such_table10430043 Ref: error_er_check_not_implemented10430141 Ref: error_er_cant_do_this_during_an_transaction10430276 Ref: error_er_error_during_commit10430443 Ref: error_er_error_during_rollback10430551 Ref: error_er_error_during_flush_logs10430663 Ref: error_er_error_during_checkpoint10430779 Ref: error_er_new_aborting_connection10430895 Ref: error_er_dump_not_implemented10431047 Ref: error_er_flush_master_binlog_closed10431202 Ref: error_er_index_rebuild10431325 Ref: error_er_master10431449 Ref: error_er_master_net_read10431541 Ref: error_er_master_net_write10431648 Ref: error_er_ft_matching_key_not_found10431754 Ref: error_er_lock_or_active_transaction10431892 Ref: error_er_unknown_system_variable10432080 Ref: error_er_crashed_on_usage10432194 Ref: error_er_crashed_on_repair10432327 Ref: error_er_warning_not_complete_rollback10432479 Ref: error_er_trans_cache_full10432642 Ref: error_er_slave_must_stop10432863 Ref: error_er_slave_not_running10433023 Ref: error_er_bad_slave10433183 Ref: error_er_master_info10433342 Ref: error_er_slave_thread10433520 Ref: error_er_too_many_user_connections10433648 Ref: error_er_set_constants_only10433812 Ref: error_er_lock_wait_timeout10433939 Ref: error_er_lock_table_full10434073 Ref: error_er_read_only_transaction10434204 Ref: error_er_drop_db_with_read_lock10434362 Ref: error_er_create_db_with_read_lock10434518 Ref: error_er_wrong_arguments10434678 Ref: error_er_no_permission_to_create_user10434781 Ref: error_er_union_tables_in_different_dir10434921 Ref: error_er_lock_deadlock10435096 Ref: error_er_table_cant_handle_ft10435243 Ref: error_er_cannot_add_foreign10435378 Ref: error_er_no_referenced_row10435492 Ref: error_er_row_is_referenced10435641 Ref: error_er_connect_to_master10435794 Ref: error_er_query_on_master10435904 Ref: error_er_error_when_executing_command10436015 Ref: error_er_wrong_usage10436146 Ref: error_er_wrong_number_of_columns_in_select10436248 Ref: error_er_cant_update_with_readlock10436415 Ref: error_er_mixing_not_allowed10436572 Ref: error_er_dup_argument10436722 Ref: error_er_user_limit_reached10436832 Ref: error_er_specific_access_denied_error10436979 Ref: error_er_local_variable10437139 Ref: error_er_global_variable10437290 Ref: error_er_no_default10437441 Ref: error_er_wrong_value_for_var10437556 Ref: error_er_wrong_type_for_var10437685 Ref: error_er_var_cant_be_read10437806 Ref: error_er_cant_use_option_here10437924 Ref: error_er_not_supported_yet10438040 Ref: error_er_master_fatal_error_reading_binlog10438166 Ref: error_er_slave_ignored_table10438342 Ref: error_er_incorrect_global_local_var10438498 Ref: error_er_wrong_fk_def10438617 Ref: error_er_key_ref_do_not_match_table_ref10438737 Ref: error_er_operand_columns10438880 Ref: error_er_subquery_no_1_row10438993 Ref: error_er_unknown_stmt_handler10439105 Ref: error_er_corrupt_help_db10439241 Ref: error_er_cyclic_reference10439361 Ref: error_er_auto_convert10439470 Ref: error_er_illegal_reference10439581 Ref: error_er_derived_must_have_alias10439694 Ref: error_er_select_reduced10439823 Ref: error_er_tablename_not_allowed_here10439941 Ref: error_er_not_supported_auth_mode10440085 Ref: error_er_spatial_cant_have_null10440276 Ref: error_er_collation_charset_mismatch10440406 Ref: error_er_slave_was_running10440545 Ref: error_er_slave_was_not_running10440649 Ref: error_er_too_big_for_uncompress10440763 Ref: error_er_zlib_z_mem_error10440963 Ref: error_er_zlib_z_buf_error10441065 Ref: error_er_zlib_z_data_error10441245 Ref: error_er_cut_value_group_concat10441351 Ref: error_er_warn_too_few_records10441473 Ref: error_er_warn_too_many_records10441600 Ref: error_er_warn_null_to_notnull10441764 Ref: error_er_warn_data_out_of_range10441929 Ref: error_warn_data_truncated10442059 Ref: error_er_warn_using_other_handler10442179 Ref: error_er_cant_aggregate_2collations10442304 Ref: error_er_drop_user10442462 Ref: error_er_revoke_grants10442580 Ref: error_er_cant_aggregate_3collations10442727 Ref: error_er_cant_aggregate_ncollations10442891 Ref: error_er_variable_is_not_struct10443024 Ref: error_er_unknown_collation10443193 Ref: error_er_slave_ignored_ssl_params10443296 Ref: error_er_server_is_in_secure_auth_mode10443553 Ref: error_er_warn_field_resolved10443792 Ref: error_er_bad_slave_until_cond10443951 Ref: error_er_missing_skip_slave10444109 Ref: error_er_until_cond_ignored10444383 Ref: error_er_wrong_name_for_index10444529 Ref: error_er_wrong_name_for_catalog10444637 Ref: error_er_warn_qc_resize10444749 Ref: error_er_bad_ft_column10444894 Ref: error_er_unknown_key_cache10445014 Ref: error_er_warn_hostname_wont_work10445116 Ref: error_er_unknown_storage_engine10445314 Ref: error_er_warn_deprecated_syntax10445424 Ref: error_er_non_updatable_table10445595 Ref: error_er_feature_disabled10445723 Ref: error_er_option_prevents_statement10445886 Ref: error_er_duplicated_value_in_type10446061 Ref: error_er_truncated_wrong_value10446191 Ref: error_er_too_much_auto_timestamp_cols10446309 Ref: error_er_invalid_on_update10446535 Ref: error_er_unsupported_ps10446655 Ref: error_er_get_errmsg10446805 Ref: error_er_get_temporary_errmsg10446903 Ref: error_er_unknown_time_zone10447021 Ref: error_er_warn_invalid_timestamp10447137 Ref: error_er_invalid_character_string10447271 Ref: error_er_warn_allowed_packet_overflowed10447391 Ref: error_er_conflicting_declarations10447561 Ref: error_er_sp_no_recursive_create10447691 Ref: error_er_sp_already_exists10447828 Ref: error_er_sp_does_not_exist10447928 Ref: error_er_sp_drop_failed10448028 Ref: error_er_sp_store_failed10448125 Ref: error_er_sp_lilabel_mismatch10448225 Ref: error_er_sp_label_redefine10448336 Ref: error_er_sp_label_mismatch10448435 Ref: error_er_sp_uninit_var10448541 Ref: error_er_sp_badselect10448655 Ref: error_er_sp_badreturn10448794 Ref: error_er_sp_badstatement10448905 Ref: error_er_update_log_deprecated_ignored10449021 Ref: error_er_update_log_deprecated_translated10449267 Ref: error_er_query_interrupted10449538 Ref: error_er_sp_wrong_no_of_args10449649 Ref: error_er_sp_cond_mismatch10449796 Ref: error_er_sp_noreturn10449898 Ref: error_er_sp_noreturnend10450002 Ref: error_er_sp_bad_cursor_query10450111 Ref: error_er_sp_bad_cursor_select10450226 Ref: error_er_sp_cursor_mismatch10450341 Ref: error_er_sp_cursor_already_open10450442 Ref: error_er_sp_cursor_not_open10450549 Ref: error_er_sp_undeclared_var10450648 Ref: error_er_sp_wrong_no_of_fetch_args10450751 Ref: error_er_sp_fetch_no_data10450874 Ref: error_er_sp_dup_param10451004 Ref: error_er_sp_dup_var10451102 Ref: error_er_sp_dup_cond10451197 Ref: error_er_sp_dup_curs10451294 Ref: error_er_sp_cant_alter10451388 Ref: error_er_sp_subselect_nyi10451485 Ref: error_er_stmt_not_allowed_in_sf_or_trg10451592 Ref: error_er_sp_varcond_after_curshndlr10451736 Ref: error_er_sp_cursor_after_handler10451899 Ref: error_er_sp_case_not_found10452029 Ref: error_er_fparser_too_big_file10452142 Ref: error_er_fparser_bad_header10452259 Ref: error_er_fparser_eof_in_comment10452379 Ref: error_er_fparser_error_in_parameter10452513 Ref: error_er_fparser_eof_in_unknown_parameter10452649 Ref: error_er_view_no_explain10452814 Ref: error_er_frm_unknown_type10452968 Ref: error_er_wrong_object10453092 Ref: error_er_nonupdateable_column10453184 Ref: error_er_view_select_derived10453295 Ref: error_er_view_select_clause10453429 Ref: error_er_view_select_variable10453546 Ref: error_er_view_select_tmptable10453675 Ref: error_er_view_wrong_list10453804 Ref: error_er_warn_view_merge10453951 Ref: error_er_warn_view_without_key10454111 Ref: error_er_view_invalid10454271 Ref: error_er_sp_no_drop_sp10454470 Ref: error_er_sp_goto_in_hndlr10454610 Ref: error_er_trg_already_exists10454738 Ref: error_er_trg_does_not_exist10454841 Ref: error_er_trg_on_view_or_temp_table10454944 Ref: error_er_trg_cant_change_row10455073 Ref: error_er_trg_no_such_row_in_trg10455201 Ref: error_er_no_default_for_field10455318 Ref: error_er_division_by_zero10455440 Ref: error_er_truncated_wrong_value_for_field10455532 Ref: error_er_illegal_value_for_type10455682 Ref: error_er_view_nonupd_check10455809 Ref: error_er_view_check_failed10455931 Ref: error_er_procaccess_denied_error10456038 Ref: error_er_relay_log_fail10456176 Ref: error_er_passwd_length10456286 Ref: error_er_unknown_target_binlog10456415 Ref: error_er_io_err_log_index_read10456535 Ref: error_er_binlog_purge_prohibited10456651 Ref: error_er_fseek_fail10456786 Ref: error_er_binlog_purge_fatal_err10456876 Ref: error_er_log_in_use10456989 Ref: error_er_log_purge_unknown_err10457103 Ref: error_er_relay_log_init10457217 Ref: error_er_no_binary_logging10457336 Ref: error_er_reserved_syntax10457448 Ref: error_er_wsas_failed10457600 Ref: error_er_diff_groups_proc10457691 Ref: error_er_no_group_for_proc10457819 Ref: error_er_order_with_proc10457943 Ref: error_er_logging_prohibit_changing_of10458063 Ref: error_er_no_file_mapping10458231 Ref: error_er_wrong_magic10458338 Ref: error_er_ps_many_param10458429 Ref: error_er_key_part_010458554 Ref: error_er_view_checksum10458659 Ref: error_er_view_multiupdate10458760 Ref: error_er_view_no_insert_field_list10458911 Ref: error_er_view_delete_merge_view10459056 Ref: error_er_cannot_user10459178 Ref: error_er_xaer_nota10459278 Ref: error_er_xaer_inval10459372 Ref: error_er_xaer_rmfail10459499 Ref: error_er_xaer_outside10459664 Ref: error_er_xaer_rmerr10459797 Ref: error_er_xa_rbrollback10459967 Ref: error_er_nonexisting_proc_grant10460092 Ref: error_er_proc_auto_grant_fail10460255 Ref: error_er_proc_auto_revoke_fail10460390 Ref: error_er_data_too_long10460524 Ref: error_er_sp_bad_sqlstate10460640 Ref: error_er_startup10460736 Ref: error_er_load_from_fixed_size_rows_to_var10460876 Ref: error_er_cant_create_user_with_grant10461040 Ref: error_er_wrong_value_for_type10461177 Ref: error_er_table_def_changed10461300 Ref: error_er_sp_dup_handler10461434 Ref: error_er_sp_not_var_arg10461555 Ref: error_er_sp_no_retset10461735 Ref: error_er_cant_create_geometry_object10461854 Ref: error_er_failed_routine_break_binlog10462016 Ref: error_er_binlog_unsafe_routine10462310 Ref: error_er_binlog_create_routine_need_super10462605 Ref: error_er_exec_stmt_with_open_cursor10462861 Ref: error_er_stmt_has_no_open_cursor10463076 Ref: error_er_commit_not_allowed_in_sf_or_trg10463201 Ref: error_er_no_default_for_view_field10463378 Ref: error_er_sp_no_recursion10463538 Ref: error_er_too_big_scale10463672 Ref: error_er_too_big_precision10463812 Ref: error_er_m_bigger_than_d10463960 Ref: error_er_wrong_lock_of_system_table10464117 Ref: error_er_connect_to_foreign_data_source10464291 Ref: error_er_query_on_foreign_data_source10464433 Ref: error_er_foreign_data_source_doesnt_exist10464624 Ref: error_er_foreign_data_string_invalid_cant_create10464818 Ref: error_er_foreign_data_string_invalid10465027 Ref: error_er_cant_create_federated_table10465189 Ref: error_er_trg_in_wrong_schema10465335 Ref: error_er_stack_overrun_need_more10465440 Ref: error_er_too_long_body10465673 Ref: error_er_warn_cant_drop_default_keycache10465782 Ref: error_er_too_big_displaywidth10465909 Ref: error_er_xaer_dupid10466046 Ref: error_er_datetime_function_overflow10466153 Ref: error_er_cant_update_used_table_in_sf_or_trg10466278 Ref: error_er_view_prevent_update10466525 Ref: error_er_ps_no_recursion10466677 Ref: error_er_sp_cant_set_autocommit10466930 Ref: error_er_malformed_definer10467083 Ref: error_er_view_frm_no_user10467193 Ref: error_er_view_other_user10467397 Ref: error_er_no_such_user10467549 Ref: error_er_forbid_schema_change10467682 Ref: error_er_row_is_referenced_210467814 Ref: error_er_no_referenced_row_210467974 Ref: error_er_sp_bad_var_shadow10468130 Ref: error_er_trg_no_definer10468261 Ref: error_er_old_file_format10468530 Ref: error_er_sp_recursion_limit10468676 Ref: error_er_sp_proc_table_corrupt10468856 Ref: error_er_sp_wrong_name10469053 Ref: error_er_table_needs_upgrade10469156 Ref: error_er_sp_no_aggregate10469322 Ref: error_er_max_prepared_stmt_count_reached10469447 Ref: error_er_view_recursive10469629 Ref: error_er_non_grouping_field_used10469739 Ref: error_er_table_cant_handle_spkeys10469869 Ref: error_er_no_triggers_on_system_schema10470007 Ref: error_er_removed_spaces10470147 Ref: error_er_autoinc_read_failed10470265 Ref: error_er_username10470402 Ref: error_er_hostname10470482 Ref: error_er_wrong_string_length10470562 Ref: error_er_non_insertable_table10470709 Ref: error_er_admin_wrong_mrg_table10470844 Ref: error_er_too_high_level_of_nesting_for_select10471005 Ref: error_er_name_becomes_empty10471145 Ref: error_er_ambiguous_field_term10471248 Ref: error_er_foreign_server_exists10471454 Ref: error_er_foreign_server_doesnt_exist10471607 Ref: error_er_illegal_ha_create_option10471791 Ref: error_er_partition_requires_values_error10471948 Ref: error_er_partition_wrong_values_error10472133 Ref: error_er_partition_maxvalue_error10472296 Ref: error_er_partition_subpartition_error10472437 Ref: error_er_partition_subpart_mix_error10472585 Ref: error_er_partition_wrong_no_part_error10472743 Ref: error_er_partition_wrong_no_subpart_error10472911 Ref: error_er_wrong_expr_in_partition_func_error10473085 Ref: error_er_no_const_expr_in_range_or_list_error10473288 Ref: error_er_field_not_found_part_error10473440 Ref: error_er_list_of_fields_only_in_hash_error10473599 Ref: error_er_inconsistent_partition_info_error10473748 Ref: error_er_partition_func_not_allowed_error10473949 Ref: error_er_partitions_must_be_defined_error10474087 Ref: error_er_range_not_increasing_error10474235 Ref: error_er_inconsistent_type_of_functions_error10474398 Ref: error_er_multiple_def_const_in_list_part_error10474557 Ref: error_er_partition_entry_error10474719 Ref: error_er_mix_handler_error10474852 Ref: error_er_partition_not_defined_error10475014 Ref: error_er_too_many_partitions_error10475168 Ref: error_er_subpartition_error10475314 Ref: error_er_cant_create_handler_file10475497 Ref: error_er_blob_field_in_part_func_error10475622 Ref: error_er_unique_key_need_all_fields_in_pf10475768 Ref: error_er_no_parts_error10475939 Ref: error_er_partition_mgmt_on_nonpartitioned10476056 Ref: error_er_foreign_key_on_partitioned10476224 Ref: error_er_drop_partition_non_existent10476390 Ref: error_er_drop_last_partition10476513 Ref: error_er_coalesce_only_on_hash_partition10476647 Ref: error_er_reorg_hash_only_on_same_no10476804 Ref: error_er_reorg_no_param_error10476988 Ref: error_er_only_on_range_list_partition10477181 Ref: error_er_add_partition_subpart_error10477331 Ref: error_er_add_partition_no_new_partition10477487 Ref: error_er_coalesce_partition_no_partition10477621 Ref: error_er_reorg_partition_not_exist10477760 Ref: error_er_same_name_partition10477903 Ref: error_er_no_binlog_error10478012 Ref: error_er_consecutive_reorg_partitions10478142 Ref: error_er_reorg_outside_range10478314 Ref: error_er_partition_function_failure10478514 Ref: error_er_part_state_error10478673 Ref: error_er_limited_part_range10478809 Ref: error_er_plugin_is_not_loaded10478944 Ref: error_er_wrong_value10479052 Ref: error_er_no_partition_for_given_value10479150 Ref: error_er_filegroup_option_only_once10479281 Ref: error_er_create_filegroup_failed10479416 Ref: error_er_drop_filegroup_failed10479521 Ref: error_er_tablespace_auto_extend_error10479622 Ref: error_er_wrong_size_number10479771 Ref: error_er_size_overflow_error10479932 Ref: error_er_alter_filegroup_failed10480106 Ref: error_er_binlog_row_logging_failed10480210 Ref: error_er_binlog_row_wrong_table_def10480348 Ref: error_er_binlog_row_rbr_to_sbr10480492 Ref: error_er_event_already_exists10480704 Ref: error_er_event_store_failed10480812 Ref: error_er_event_does_not_exist10480958 Ref: error_er_event_cant_alter10481059 Ref: error_er_event_drop_failed10481164 Ref: error_er_event_interval_not_positive_or_too_big10481261 Ref: error_er_event_ends_before_starts10481409 Ref: error_er_event_exec_time_in_the_past10481535 Ref: error_er_event_open_table_failed10481690 Ref: error_er_event_neither_m_expr_nor_m_at10481802 Ref: error_er_col_count_doesnt_match_corrupted10481930 Ref: error_er_cannot_load_from_table10482124 Ref: error_er_event_cannot_delete10482267 Ref: error_er_event_compile_error10482392 Ref: error_er_event_same_name10482514 Ref: error_er_event_data_too_long10482619 Ref: error_er_drop_index_fk10482730 Ref: error_er_warn_deprecated_syntax_with_ver10482864 Ref: error_er_cant_write_lock_log_table10483052 Ref: error_er_cant_lock_log_table10483207 Ref: error_er_foreign_duplicate_key10483325 Ref: error_er_col_count_doesnt_match_please_update10483514 Ref: error_er_temp_table_prevents_switch_out_of_rbr10483768 Ref: error_er_stored_function_prevents_switch_binlog_format10483973 Ref: error_er_ndb_cant_switch_binlog_format10484166 Ref: error_er_partition_no_temporary10484349 Ref: error_er_partition_const_domain_error10484479 Ref: error_er_partition_function_is_not_allowed10484629 Ref: error_er_ddl_log_error10484768 Ref: error_er_null_in_values_less_than10484860 Ref: error_er_wrong_partition_name10484996 Ref: error_er_cant_change_tx_isolation10485103 Ref: error_er_dup_entry_autoincrement_case10485274 Ref: error_er_event_modify_queue_error10485469 Ref: error_er_event_set_var_error10485583 Ref: error_er_partition_merge_error10485732 Ref: error_er_cant_activate_log10485859 Ref: error_er_rbr_not_available10485963 Ref: error_er_base64_decode_error10486094 Ref: error_er_event_recursion_forbidden10486208 Ref: error_er_events_db_error10486368 Ref: error_er_only_integers_allowed10486546 Ref: error_er_unsuported_log_engine10486666 Ref: error_er_bad_log_statement10486800 Ref: error_er_cant_rename_log_table10486929 Ref: error_er_wrong_paramcount_to_native_fct10487178 Ref: error_er_wrong_parameters_to_native_fct10487342 Ref: error_er_wrong_parameters_to_stored_fct10487496 Ref: error_er_native_fct_name_collision10487650 Ref: error_er_dup_entry_with_key_name10487795 Ref: error_er_binlog_purge_emfile10487914 Ref: error_er_event_cannot_create_in_the_past10488051 Ref: error_er_event_cannot_alter_in_the_past10488279 Ref: error_er_slave_incident10488506 Ref: error_er_no_partition_for_given_value_silent10488633 Ref: error_er_binlog_unsafe_statement10488783 Ref: error_er_slave_fatal_error10488922 Ref: error_er_slave_relay_log_read_failure10489017 Ref: error_er_slave_relay_log_write_failure10489139 Ref: error_er_slave_create_event_failure10489263 Ref: error_er_slave_master_com_failure10489371 Ref: error_er_binlog_logging_impossible10489486 Ref: error_er_view_no_creation_ctx10489614 Ref: error_er_view_invalid_creation_ctx10489735 Ref: error_er_sr_invalid_creation_ctx10489868 Ref: error_er_trg_corrupted_file10490009 Ref: error_er_trg_no_creation_ctx10490128 Ref: error_er_trg_invalid_creation_ctx10490263 Ref: error_er_event_invalid_creation_ctx10490404 Ref: error_er_trg_cant_open_table10490539 Ref: error_er_cant_create_sroutine10490660 Ref: error_er_slave_ambigous_exec_mode10490792 Ref: error_er_no_format_description_event_before_binlog_statement10490916 Ref: error_er_slave_corrupt_event10491132 Ref: error_er_load_data_invalid_column10491254 Ref: error_er_log_purge_no_file10491383 Ref: error_er_xa_rbtimeout10491496 Ref: error_er_xa_rbdeadlock10491639 Ref: error_er_need_reprepare10491792 Ref: error_er_delayed_not_supported10491911 Ref: error_warn_no_master_info10492038 Ref: error_warn_option_ignored10492157 Ref: error_warn_plugin_delete_builtin10492255 Ref: error_warn_plugin_busy10492375 Ref: error_er_variable_is_readonly10492501 Ref: error_er_warn_engine_transaction_rollback10492650 Ref: error_er_slave_heartbeat_failure10492864 Ref: error_er_slave_heartbeat_value_out_of_range10492988 Ref: error_er_ndb_replication_schema_error10493140 Ref: error_er_conflict_fn_parse_error10493291 Ref: error_er_exceptions_write_error10493424 Ref: error_er_too_long_table_comment10493555 Ref: error_er_too_long_field_comment10493686 Ref: error_er_func_inexistent_name_collision10493817 Ref: error_er_database_name10494028 Ref: error_er_table_name10494112 Ref: error_er_partition_name10494190 Ref: error_er_subpartition_name10494276 Ref: error_er_temporary_name10494368 Ref: error_er_renamed_name10494454 Ref: error_er_too_many_concurrent_trxs10494536 Ref: error_warn_non_ascii_separator_not_implemented10494662 Ref: error_er_debug_sync_timeout10494820 Ref: error_er_debug_sync_hit_limit10494932 Node: error-messages-client10495044 Ref: error_cr_unknown_error10495804 Ref: error_cr_socket_create_error10495881 Ref: error_cr_connection_error10495974 Ref: error_cr_conn_host_error10496100 Ref: error_cr_ipsock_error10496202 Ref: error_cr_unknown_host10496290 Ref: error_cr_server_gone_error10496382 Ref: error_cr_version_error10496470 Ref: error_cr_out_of_memory10496592 Ref: error_cr_wrong_host_info10496680 Ref: error_cr_localhost_connection10496755 Ref: error_cr_tcp_connection10496845 Ref: error_cr_server_handshake_err10496917 Ref: error_cr_server_lost10497007 Ref: error_cr_commands_out_of_sync10497107 Ref: error_cr_namedpipe_connection10497224 Ref: error_cr_namedpipewait_error10497303 Ref: error_cr_namedpipeopen_error10497419 Ref: error_cr_namedpipesetstate_error10497531 Ref: error_cr_cant_read_charset10497655 Ref: error_cr_net_packet_too_large10497761 Ref: error_cr_embedded_connection10497875 Ref: error_cr_probe_slave_status10497954 Ref: error_cr_probe_slave_hosts10498044 Ref: error_cr_probe_slave_connect10498132 Ref: error_cr_probe_master_connect10498222 Ref: error_cr_ssl_connection_error10498314 Ref: error_cr_malformed_packet10498399 Ref: error_cr_wrong_license10498476 Ref: error_cr_null_pointer10498622 Ref: error_cr_no_prepare_stmt10498706 Ref: error_cr_params_not_bound10498788 Ref: error_cr_data_truncated10498902 Ref: error_cr_no_parameters_exists10498975 Ref: error_cr_invalid_parameter_no10499076 Ref: error_cr_invalid_buffer_use10499165 Ref: error_cr_unsupported_param_type10499306 Ref: error_cr_shared_memory_connection10499422 Ref: error_cr_shared_memory_connect_request_error10499508 Ref: error_cr_shared_memory_connect_answer_error10499662 Ref: error_cr_shared_memory_connect_file_map_error10499814 Ref: error_cr_shared_memory_connect_map_error10499970 Ref: error_cr_shared_memory_file_map_error10500127 Ref: error_cr_shared_memory_map_error10500275 Ref: error_cr_shared_memory_event_error10500424 Ref: error_cr_shared_memory_connect_abandoned_error10500563 Ref: error_cr_shared_memory_connect_set_error10500698 Ref: error_cr_conn_unknow_protocol10500846 Ref: error_cr_invalid_conn_handle10500936 Ref: error_cr_secure_auth10501025 Ref: error_cr_fetch_canceled10501188 Ref: error_cr_no_data10501300 Ref: error_cr_no_stmt_metadata10501398 Ref: error_cr_no_result_set10501498 Ref: error_cr_not_implemented10501641 Ref: error_cr_server_lost_extended10501736 Ref: error_cr_stmt_closed10501858 Ref: error_cr_new_stmt_metadata10501980 Node: problems10502221 Node: what-is-crashing10503059 Node: common-errors10507336 Node: error-access-denied10508996 Node: can-not-connect-to-server10509390 Node: can-not-connect-to-server-on-windows10517306 Node: error-lost-connection10521057 Node: old-client10522845 Node: password-too-long10526368 Node: blocked-host10527289 Node: too-many-connections10528706 Node: out-of-memory10530684 Node: gone-away10531648 Node: packet-too-large10538925 Node: communication-errors10541473 Node: full-table10544302 Node: cannot-create10544765 Node: commands-out-of-sync10546278 Node: ignoring-user10546991 Node: cannot-find-table10548420 Node: cannot-initialize-character-set10549422 Node: not-enough-file-handles10551156 Node: table-corruption10554242 Node: installation-issues10555015 Node: file-permissions10555274 Node: administration-issues10556538 Node: resetting-permissions10557136 Node: resetting-permissions-windows10558123 Node: resetting-permissions-unix10561419 Node: resetting-permissions-generic10564853 Node: crashing10566407 Node: full-disk10575358 Node: temporary-files10577482 Node: problems-with-mysql-sock10580242 Node: timezone-problems10582476 Node: query-issues10583411 Node: case-sensitivity10584130 Node: using-date10588627 Node: problems-with-null10593480 Node: problems-with-alias10596888 Node: non-transactional-tables10598655 Node: deleting-from-related-tables10600501 Node: no-matching-rows10601252 Node: problems-with-float10603422 Node: optimizer-issues10607804 Node: table-definition-issues10609588 Node: alter-table-problems10609902 Node: temporary-table-problems10611873 Node: bugs10613152 Node: news10623787 Node: news-5-1-x10625944 Node: news-5-1-5910631732 Node: news-5-1-5810633401 Node: news-5-1-5710638266 Node: news-5-1-5610645252 Node: news-5-1-5510650534 Node: news-5-1-5410662236 Node: news-5-1-5310667439 Node: news-5-1-52sp110673883 Node: news-5-1-5210677039 Node: news-5-1-5110685290 Node: news-5-1-5010697856 Node: news-5-1-49sp110704798 Node: news-5-1-4910705644 Node: news-5-1-4810716300 Node: news-5-1-4710726246 Node: news-5-1-46sp110737214 Node: news-5-1-4610741167 Node: news-5-1-4510758655 Node: news-5-1-4410766916 Node: news-5-1-43sp110773582 Node: news-5-1-4310775497 Node: news-5-1-4210787906 Node: news-5-1-4110800276 Node: news-5-1-40sp110823103 Node: news-5-1-4010828161 Node: news-5-1-3910840852 Node: news-5-1-3810853591 Node: news-5-1-37sp110869108 Node: news-5-1-3710871191 Node: news-5-1-3610883251 Node: news-5-1-3510902092 Node: news-5-1-34sp110915450 Node: news-5-1-3410918677 Node: news-5-1-3310925510 Node: news-5-1-3210942960 Node: news-5-1-31sp110956752 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